PK ]ZZZ��l��+ �+ isympy.py"""
Python shell for SymPy.
This is just a normal Python shell (IPython shell if you have the
IPython package installed), that executes the following commands for
the user:
>>> from __future__ import division
>>> from sympy import *
>>> x, y, z, t = symbols('x y z t')
>>> k, m, n = symbols('k m n', integer=True)
>>> f, g, h = symbols('f g h', cls=Function)
>>> init_printing()
So starting 'isympy' is equivalent to starting Python (or IPython) and
executing the above commands by hand. It is intended for easy and quick
experimentation with SymPy. isympy is a good way to use SymPy as an
interactive calculator. If you have IPython and Matplotlib installed, then
interactive plotting is enabled by default.
COMMAND LINE OPTIONS
--------------------
-c CONSOLE, --console=CONSOLE
Use the specified shell (Python or IPython) shell as the console
backend instead of the default one (IPython if present, Python
otherwise), e.g.:
$isympy -c python
CONSOLE must be one of 'ipython' or 'python'
-p PRETTY, --pretty PRETTY
Setup pretty-printing in SymPy. When pretty-printing is enabled,
expressions can be printed with Unicode or ASCII. The default is
to use pretty-printing (with Unicode if the terminal supports it).
When this option is 'no', expressions will not be pretty-printed
and ASCII will be used:
$isympy -p no
PRETTY must be one of 'unicode', 'ascii', or 'no'
-t TYPES, --types=TYPES
Setup the ground types for the polys. By default, gmpy ground types
are used if gmpy2 or gmpy is installed, otherwise it falls back to python
ground types, which are a little bit slower. You can manually
choose python ground types even if gmpy is installed (e.g., for
testing purposes):
$isympy -t python
TYPES must be one of 'gmpy', 'gmpy1' or 'python'
Note that the ground type gmpy1 is primarily intended for testing; it
forces the use of gmpy version 1 even if gmpy2 is available.
This is the same as setting the environment variable
SYMPY_GROUND_TYPES to the given ground type (e.g.,
SYMPY_GROUND_TYPES='gmpy')
The ground types can be determined interactively from the variable
sympy.polys.domains.GROUND_TYPES.
-o ORDER, --order ORDER
Setup the ordering of terms for printing. The default is lex, which
orders terms lexicographically (e.g., x**2 + x + 1). You can choose
other orderings, such as rev-lex, which will use reverse
lexicographic ordering (e.g., 1 + x + x**2):
$isympy -o rev-lex
ORDER must be one of 'lex', 'rev-lex', 'grlex', 'rev-grlex',
'grevlex', 'rev-grevlex', 'old', or 'none'.
Note that for very large expressions, ORDER='none' may speed up
printing considerably but the terms will have no canonical order.
-q, --quiet
Print only Python's and SymPy's versions to stdout at startup.
-d, --doctest
Use the same format that should be used for doctests. This is
equivalent to -c python -p no.
-C, --no-cache
Disable the caching mechanism. Disabling the cache may slow certain
operations down considerably. This is useful for testing the cache,
or for benchmarking, as the cache can result in deceptive timings.
This is equivalent to setting the environment variable
SYMPY_USE_CACHE to 'no'.
-a, --auto-symbols (requires at least IPython 0.11)
Automatically create missing symbols. Normally, typing a name of a
Symbol that has not been instantiated first would raise NameError,
but with this option enabled, any undefined name will be
automatically created as a Symbol.
Note that this is intended only for interactive, calculator style
usage. In a script that uses SymPy, Symbols should be instantiated
at the top, so that it's clear what they are.
This will not override any names that are already defined, which
includes the single character letters represented by the mnemonic
QCOSINE (see the "Gotchas and Pitfalls" document in the
documentation). You can delete existing names by executing "del
name". If a name is defined, typing "'name' in dir()" will return True.
The Symbols that are created using this have default assumptions.
If you want to place assumptions on symbols, you should create them
using symbols() or var().
Finally, this only works in the top level namespace. So, for
example, if you define a function in isympy with an undefined
Symbol, it will not work.
See also the -i and -I options.
-i, --int-to-Integer (requires at least IPython 0.11)
Automatically wrap int literals with Integer. This makes it so that
things like 1/2 will come out as Rational(1, 2), rather than 0.5. This
works by preprocessing the source and wrapping all int literals with
Integer. Note that this will not change the behavior of int literals
assigned to variables, and it also won't change the behavior of functions
that return int literals.
If you want an int, you can wrap the literal in int(), e.g. int(3)/int(2)
gives 1.5 (with division imported from __future__).
-I, --interactive (requires at least IPython 0.11)
This is equivalent to --auto-symbols --int-to-Integer. Future options
designed for ease of interactive use may be added to this.
-D, --debug
Enable debugging output. This is the same as setting the
environment variable SYMPY_DEBUG to 'True'. The debug status is set
in the variable SYMPY_DEBUG within isympy.
-- IPython options
Additionally you can pass command line options directly to the IPython
interpreter (the standard Python shell is not supported). However you
need to add the '--' separator between two types of options, e.g the
startup banner option and the colors option. You need to enter the
options as required by the version of IPython that you are using, too:
in IPython 0.11,
$isympy -q -- --colors=NoColor
or older versions of IPython,
$isympy -q -- -colors NoColor
See also isympy --help.
"""
import os
import sys
# DO NOT IMPORT SYMPY HERE! Or the setting of the sympy environment variables
# by the command line will break.
def main() -> None:
from argparse import ArgumentParser, RawDescriptionHelpFormatter
VERSION = None
if '--version' in sys.argv:
# We cannot import sympy before this is run, because flags like -C and
# -t set environment variables that must be set before SymPy is
# imported. The only thing we need to import it for is to get the
# version, which only matters with the --version flag.
import sympy
VERSION = sympy.__version__
usage = 'isympy [options] -- [ipython options]'
parser = ArgumentParser(
usage=usage,
description=__doc__,
formatter_class=RawDescriptionHelpFormatter,
)
parser.add_argument('--version', action='version', version=VERSION)
parser.add_argument(
'-c', '--console',
dest='console',
action='store',
default=None,
choices=['ipython', 'python'],
metavar='CONSOLE',
help='select type of interactive session: ipython | python; defaults '
'to ipython if IPython is installed, otherwise python')
parser.add_argument(
'-p', '--pretty',
dest='pretty',
action='store',
default=None,
metavar='PRETTY',
choices=['unicode', 'ascii', 'no'],
help='setup pretty printing: unicode | ascii | no; defaults to '
'unicode printing if the terminal supports it, otherwise ascii')
parser.add_argument(
'-t', '--types',
dest='types',
action='store',
default=None,
metavar='TYPES',
choices=['gmpy', 'gmpy1', 'python'],
help='setup ground types: gmpy | gmpy1 | python; defaults to gmpy if gmpy2 '
'or gmpy is installed, otherwise python')
parser.add_argument(
'-o', '--order',
dest='order',
action='store',
default=None,
metavar='ORDER',
choices=['lex', 'grlex', 'grevlex', 'rev-lex', 'rev-grlex', 'rev-grevlex', 'old', 'none'],
help='setup ordering of terms: [rev-]lex | [rev-]grlex | [rev-]grevlex | old | none; defaults to lex')
parser.add_argument(
'-q', '--quiet',
dest='quiet',
action='store_true',
default=False,
help='print only version information at startup')
parser.add_argument(
'-d', '--doctest',
dest='doctest',
action='store_true',
default=False,
help='use the doctest format for output (you can just copy and paste it)')
parser.add_argument(
'-C', '--no-cache',
dest='cache',
action='store_false',
default=True,
help='disable caching mechanism')
parser.add_argument(
'-a', '--auto-symbols',
dest='auto_symbols',
action='store_true',
default=False,
help='automatically construct missing symbols')
parser.add_argument(
'-i', '--int-to-Integer',
dest='auto_int_to_Integer',
action='store_true',
default=False,
help="automatically wrap int literals with Integer")
parser.add_argument(
'-I', '--interactive',
dest='interactive',
action='store_true',
default=False,
help="equivalent to -a -i")
parser.add_argument(
'-D', '--debug',
dest='debug',
action='store_true',
default=False,
help='enable debugging output')
(options, ipy_args) = parser.parse_known_args()
if '--' in ipy_args:
ipy_args.remove('--')
if not options.cache:
os.environ['SYMPY_USE_CACHE'] = 'no'
if options.types:
os.environ['SYMPY_GROUND_TYPES'] = options.types
if options.debug:
os.environ['SYMPY_DEBUG'] = str(options.debug)
if options.doctest:
options.pretty = 'no'
options.console = 'python'
session = options.console
if session is not None:
ipython = session == 'ipython'
else:
try:
import IPython
ipython = True
except ImportError:
if not options.quiet:
from sympy.interactive.session import no_ipython
print(no_ipython)
ipython = False
args = {
'pretty_print': True,
'use_unicode': None,
'use_latex': None,
'order': None,
'argv': ipy_args,
}
if options.pretty == 'unicode':
args['use_unicode'] = True
elif options.pretty == 'ascii':
args['use_unicode'] = False
elif options.pretty == 'no':
args['pretty_print'] = False
if options.order is not None:
args['order'] = options.order
args['quiet'] = options.quiet
args['auto_symbols'] = options.auto_symbols or options.interactive
args['auto_int_to_Integer'] = options.auto_int_to_Integer or options.interactive
from sympy.interactive import init_session
init_session(ipython, **args)
if __name__ == "__main__":
main()
PK ]ZZZ]��
Wr Wr sympy/__init__.py"""
SymPy is a Python library for symbolic mathematics. It aims to become a
full-featured computer algebra system (CAS) while keeping the code as simple
as possible in order to be comprehensible and easily extensible. SymPy is
written entirely in Python. It depends on mpmath, and other external libraries
may be optionally for things like plotting support.
See the webpage for more information and documentation:
https://sympy.org
"""
import sys
if sys.version_info < (3, 8):
raise ImportError("Python version 3.8 or above is required for SymPy.")
del sys
try:
import mpmath
except ImportError:
raise ImportError("SymPy now depends on mpmath as an external library. "
"See https://docs.sympy.org/latest/install.html#mpmath for more information.")
del mpmath
from sympy.release import __version__
from sympy.core.cache import lazy_function
if 'dev' in __version__:
def enable_warnings():
import warnings
warnings.filterwarnings('default', '.*', DeprecationWarning, module='sympy.*')
del warnings
enable_warnings()
del enable_warnings
def __sympy_debug():
# helper function so we don't import os globally
import os
debug_str = os.getenv('SYMPY_DEBUG', 'False')
if debug_str in ('True', 'False'):
return eval(debug_str)
else:
raise RuntimeError("unrecognized value for SYMPY_DEBUG: %s" %
debug_str)
SYMPY_DEBUG = __sympy_debug() # type: bool
from .core import (sympify, SympifyError, cacheit, Basic, Atom,
preorder_traversal, S, Expr, AtomicExpr, UnevaluatedExpr, Symbol,
Wild, Dummy, symbols, var, Number, Float, Rational, Integer,
NumberSymbol, RealNumber, igcd, ilcm, seterr, E, I, nan, oo, pi, zoo,
AlgebraicNumber, comp, mod_inverse, Pow, integer_nthroot, integer_log,
trailing, Mul, prod, Add, Mod, Rel, Eq, Ne, Lt, Le, Gt, Ge, Equality,
GreaterThan, LessThan, Unequality, StrictGreaterThan, StrictLessThan,
vectorize, Lambda, WildFunction, Derivative, diff, FunctionClass,
Function, Subs, expand, PoleError, count_ops, expand_mul, expand_log,
expand_func, expand_trig, expand_complex, expand_multinomial, nfloat,
expand_power_base, expand_power_exp, arity, PrecisionExhausted, N,
evalf, Tuple, Dict, gcd_terms, factor_terms, factor_nc, evaluate,
Catalan, EulerGamma, GoldenRatio, TribonacciConstant, bottom_up, use,
postorder_traversal, default_sort_key, ordered, num_digits)
from .logic import (to_cnf, to_dnf, to_nnf, And, Or, Not, Xor, Nand, Nor,
Implies, Equivalent, ITE, POSform, SOPform, simplify_logic, bool_map,
true, false, satisfiable)
from .assumptions import (AppliedPredicate, Predicate, AssumptionsContext,
assuming, Q, ask, register_handler, remove_handler, refine)
from .polys import (Poly, PurePoly, poly_from_expr, parallel_poly_from_expr,
degree, total_degree, degree_list, LC, LM, LT, pdiv, prem, pquo,
pexquo, div, rem, quo, exquo, half_gcdex, gcdex, invert,
subresultants, resultant, discriminant, cofactors, gcd_list, gcd,
lcm_list, lcm, terms_gcd, trunc, monic, content, primitive, compose,
decompose, sturm, gff_list, gff, sqf_norm, sqf_part, sqf_list, sqf,
factor_list, factor, intervals, refine_root, count_roots, all_roots,
real_roots, nroots, ground_roots, nth_power_roots_poly, cancel,
reduced, groebner, is_zero_dimensional, GroebnerBasis, poly,
symmetrize, horner, interpolate, rational_interpolate, viete, together,
BasePolynomialError, ExactQuotientFailed, PolynomialDivisionFailed,
OperationNotSupported, HeuristicGCDFailed, HomomorphismFailed,
IsomorphismFailed, ExtraneousFactors, EvaluationFailed,
RefinementFailed, CoercionFailed, NotInvertible, NotReversible,
NotAlgebraic, DomainError, PolynomialError, UnificationFailed,
GeneratorsError, GeneratorsNeeded, ComputationFailed,
UnivariatePolynomialError, MultivariatePolynomialError,
PolificationFailed, OptionError, FlagError, minpoly,
minimal_polynomial, primitive_element, field_isomorphism,
to_number_field, isolate, round_two, prime_decomp, prime_valuation,
galois_group, itermonomials, Monomial, lex, grlex,
grevlex, ilex, igrlex, igrevlex, CRootOf, rootof, RootOf,
ComplexRootOf, RootSum, roots, Domain, FiniteField, IntegerRing,
RationalField, RealField, ComplexField, PythonFiniteField,
GMPYFiniteField, PythonIntegerRing, GMPYIntegerRing, PythonRational,
GMPYRationalField, AlgebraicField, PolynomialRing, FractionField,
ExpressionDomain, FF_python, FF_gmpy, ZZ_python, ZZ_gmpy, QQ_python,
QQ_gmpy, GF, FF, ZZ, QQ, ZZ_I, QQ_I, RR, CC, EX, EXRAW,
construct_domain, swinnerton_dyer_poly, cyclotomic_poly,
symmetric_poly, random_poly, interpolating_poly, jacobi_poly,
chebyshevt_poly, chebyshevu_poly, hermite_poly, hermite_prob_poly,
legendre_poly, laguerre_poly, apart, apart_list, assemble_partfrac_list,
Options, ring, xring, vring, sring, field, xfield, vfield, sfield)
from .series import (Order, O, limit, Limit, gruntz, series, approximants,
residue, EmptySequence, SeqPer, SeqFormula, sequence, SeqAdd, SeqMul,
fourier_series, fps, difference_delta, limit_seq)
from .functions import (factorial, factorial2, rf, ff, binomial,
RisingFactorial, FallingFactorial, subfactorial, carmichael,
fibonacci, lucas, motzkin, tribonacci, harmonic, bernoulli, bell, euler,
catalan, genocchi, andre, partition, divisor_sigma, legendre_symbol,
jacobi_symbol, kronecker_symbol, mobius, primenu, primeomega,
totient, reduced_totient, primepi, sqrt, root, Min, Max, Id,
real_root, Rem, cbrt, re, im, sign, Abs, conjugate, arg, polar_lift,
periodic_argument, unbranched_argument, principal_branch, transpose,
adjoint, polarify, unpolarify, sin, cos, tan, sec, csc, cot, sinc,
asin, acos, atan, asec, acsc, acot, atan2, exp_polar, exp, ln, log,
LambertW, sinh, cosh, tanh, coth, sech, csch, asinh, acosh, atanh,
acoth, asech, acsch, floor, ceiling, frac, Piecewise, piecewise_fold,
piecewise_exclusive, erf, erfc, erfi, erf2, erfinv, erfcinv, erf2inv,
Ei, expint, E1, li, Li, Si, Ci, Shi, Chi, fresnels, fresnelc, gamma,
lowergamma, uppergamma, polygamma, loggamma, digamma, trigamma,
multigamma, dirichlet_eta, zeta, lerchphi, polylog, stieltjes, Eijk,
LeviCivita, KroneckerDelta, SingularityFunction, DiracDelta, Heaviside,
bspline_basis, bspline_basis_set, interpolating_spline, besselj,
bessely, besseli, besselk, hankel1, hankel2, jn, yn, jn_zeros, hn1,
hn2, airyai, airybi, airyaiprime, airybiprime, marcumq, hyper,
meijerg, appellf1, legendre, assoc_legendre, hermite, hermite_prob,
chebyshevt, chebyshevu, chebyshevu_root, chebyshevt_root, laguerre,
assoc_laguerre, gegenbauer, jacobi, jacobi_normalized, Ynm, Ynm_c,
Znm, elliptic_k, elliptic_f, elliptic_e, elliptic_pi, beta, mathieus,
mathieuc, mathieusprime, mathieucprime, riemann_xi, betainc, betainc_regularized)
from .ntheory import (nextprime, prevprime, prime, primerange,
randprime, Sieve, sieve, primorial, cycle_length, composite,
compositepi, isprime, divisors, proper_divisors, factorint,
multiplicity, perfect_power, pollard_pm1, pollard_rho, primefactors,
divisor_count, proper_divisor_count,
factorrat,
mersenne_prime_exponent, is_perfect, is_mersenne_prime, is_abundant,
is_deficient, is_amicable, is_carmichael, abundance, npartitions, is_primitive_root,
is_quad_residue, n_order, sqrt_mod,
quadratic_residues, primitive_root, nthroot_mod, is_nthpow_residue,
sqrt_mod_iter, discrete_log, quadratic_congruence,
binomial_coefficients, binomial_coefficients_list,
multinomial_coefficients, continued_fraction_periodic,
continued_fraction_iterator, continued_fraction_reduce,
continued_fraction_convergents, continued_fraction, egyptian_fraction)
from .concrete import product, Product, summation, Sum
from .discrete import (fft, ifft, ntt, intt, fwht, ifwht, mobius_transform,
inverse_mobius_transform, convolution, covering_product,
intersecting_product)
from .simplify import (simplify, hypersimp, hypersimilar, logcombine,
separatevars, posify, besselsimp, kroneckersimp, signsimp,
nsimplify, FU, fu, sqrtdenest, cse, epath, EPath, hyperexpand,
collect, rcollect, radsimp, collect_const, fraction, numer, denom,
trigsimp, exptrigsimp, powsimp, powdenest, combsimp, gammasimp,
ratsimp, ratsimpmodprime)
from .sets import (Set, Interval, Union, EmptySet, FiniteSet, ProductSet,
Intersection, DisjointUnion, imageset, Complement, SymmetricDifference, ImageSet,
Range, ComplexRegion, Complexes, Reals, Contains, ConditionSet, Ordinal,
OmegaPower, ord0, PowerSet, Naturals, Naturals0, UniversalSet,
Integers, Rationals)
from .solvers import (solve, solve_linear_system, solve_linear_system_LU,
solve_undetermined_coeffs, nsolve, solve_linear, checksol, det_quick,
inv_quick, check_assumptions, failing_assumptions, diophantine,
rsolve, rsolve_poly, rsolve_ratio, rsolve_hyper, checkodesol,
classify_ode, dsolve, homogeneous_order, solve_poly_system,
solve_triangulated, pde_separate, pde_separate_add, pde_separate_mul,
pdsolve, classify_pde, checkpdesol, ode_order, reduce_inequalities,
reduce_abs_inequality, reduce_abs_inequalities, solve_poly_inequality,
solve_rational_inequalities, solve_univariate_inequality, decompogen,
solveset, linsolve, linear_eq_to_matrix, nonlinsolve, substitution)
from .matrices import (ShapeError, NonSquareMatrixError, GramSchmidt,
casoratian, diag, eye, hessian, jordan_cell, list2numpy, matrix2numpy,
matrix_multiply_elementwise, ones, randMatrix, rot_axis1, rot_axis2,
rot_axis3, symarray, wronskian, zeros, MutableDenseMatrix,
DeferredVector, MatrixBase, Matrix, MutableMatrix,
MutableSparseMatrix, banded, ImmutableDenseMatrix,
ImmutableSparseMatrix, ImmutableMatrix, SparseMatrix, MatrixSlice,
BlockDiagMatrix, BlockMatrix, FunctionMatrix, Identity, Inverse,
MatAdd, MatMul, MatPow, MatrixExpr, MatrixSymbol, Trace, Transpose,
ZeroMatrix, OneMatrix, blockcut, block_collapse, matrix_symbols,
Adjoint, hadamard_product, HadamardProduct, HadamardPower,
Determinant, det, diagonalize_vector, DiagMatrix, DiagonalMatrix,
DiagonalOf, trace, DotProduct, kronecker_product, KroneckerProduct,
PermutationMatrix, MatrixPermute, Permanent, per, rot_ccw_axis1,
rot_ccw_axis2, rot_ccw_axis3, rot_givens)
from .geometry import (Point, Point2D, Point3D, Line, Ray, Segment, Line2D,
Segment2D, Ray2D, Line3D, Segment3D, Ray3D, Plane, Ellipse, Circle,
Polygon, RegularPolygon, Triangle, rad, deg, are_similar, centroid,
convex_hull, idiff, intersection, closest_points, farthest_points,
GeometryError, Curve, Parabola)
from .utilities import (flatten, group, take, subsets, variations,
numbered_symbols, cartes, capture, dict_merge, prefixes, postfixes,
sift, topological_sort, unflatten, has_dups, has_variety, reshape,
rotations, filldedent, lambdify,
threaded, xthreaded, public, memoize_property, timed)
from .integrals import (integrate, Integral, line_integrate, mellin_transform,
inverse_mellin_transform, MellinTransform, InverseMellinTransform,
laplace_transform, laplace_correspondence, laplace_initial_conds,
inverse_laplace_transform, LaplaceTransform,
InverseLaplaceTransform, fourier_transform, inverse_fourier_transform,
FourierTransform, InverseFourierTransform, sine_transform,
inverse_sine_transform, SineTransform, InverseSineTransform,
cosine_transform, inverse_cosine_transform, CosineTransform,
InverseCosineTransform, hankel_transform, inverse_hankel_transform,
HankelTransform, InverseHankelTransform, singularityintegrate)
from .tensor import (IndexedBase, Idx, Indexed, get_contraction_structure,
get_indices, shape, MutableDenseNDimArray, ImmutableDenseNDimArray,
MutableSparseNDimArray, ImmutableSparseNDimArray, NDimArray,
tensorproduct, tensorcontraction, tensordiagonal, derive_by_array,
permutedims, Array, DenseNDimArray, SparseNDimArray)
from .parsing import parse_expr
from .calculus import (euler_equations, singularities, is_increasing,
is_strictly_increasing, is_decreasing, is_strictly_decreasing,
is_monotonic, finite_diff_weights, apply_finite_diff,
differentiate_finite, periodicity, not_empty_in, AccumBounds,
is_convex, stationary_points, minimum, maximum)
from .algebras import Quaternion
from .printing import (pager_print, pretty, pretty_print, pprint,
pprint_use_unicode, pprint_try_use_unicode, latex, print_latex,
multiline_latex, mathml, print_mathml, python, print_python, pycode,
ccode, print_ccode, smtlib_code, glsl_code, print_glsl, cxxcode, fcode,
print_fcode, rcode, print_rcode, jscode, print_jscode, julia_code,
mathematica_code, octave_code, rust_code, print_gtk, preview, srepr,
print_tree, StrPrinter, sstr, sstrrepr, TableForm, dotprint,
maple_code, print_maple_code)
test = lazy_function('sympy.testing.runtests_pytest', 'test')
doctest = lazy_function('sympy.testing.runtests', 'doctest')
# This module causes conflicts with other modules:
# from .stats import *
# Adds about .04-.05 seconds of import time
# from combinatorics import *
# This module is slow to import:
#from physics import units
from .plotting import plot, textplot, plot_backends, plot_implicit, plot_parametric
from .interactive import init_session, init_printing, interactive_traversal
evalf._create_evalf_table()
__all__ = [
'__version__',
# sympy.core
'sympify', 'SympifyError', 'cacheit', 'Basic', 'Atom',
'preorder_traversal', 'S', 'Expr', 'AtomicExpr', 'UnevaluatedExpr',
'Symbol', 'Wild', 'Dummy', 'symbols', 'var', 'Number', 'Float',
'Rational', 'Integer', 'NumberSymbol', 'RealNumber', 'igcd', 'ilcm',
'seterr', 'E', 'I', 'nan', 'oo', 'pi', 'zoo', 'AlgebraicNumber', 'comp',
'mod_inverse', 'Pow', 'integer_nthroot', 'integer_log', 'trailing', 'Mul', 'prod',
'Add', 'Mod', 'Rel', 'Eq', 'Ne', 'Lt', 'Le', 'Gt', 'Ge', 'Equality',
'GreaterThan', 'LessThan', 'Unequality', 'StrictGreaterThan',
'StrictLessThan', 'vectorize', 'Lambda', 'WildFunction', 'Derivative',
'diff', 'FunctionClass', 'Function', 'Subs', 'expand', 'PoleError',
'count_ops', 'expand_mul', 'expand_log', 'expand_func', 'expand_trig',
'expand_complex', 'expand_multinomial', 'nfloat', 'expand_power_base',
'expand_power_exp', 'arity', 'PrecisionExhausted', 'N', 'evalf', 'Tuple',
'Dict', 'gcd_terms', 'factor_terms', 'factor_nc', 'evaluate', 'Catalan',
'EulerGamma', 'GoldenRatio', 'TribonacciConstant', 'bottom_up', 'use',
'postorder_traversal', 'default_sort_key', 'ordered', 'num_digits',
# sympy.logic
'to_cnf', 'to_dnf', 'to_nnf', 'And', 'Or', 'Not', 'Xor', 'Nand', 'Nor',
'Implies', 'Equivalent', 'ITE', 'POSform', 'SOPform', 'simplify_logic',
'bool_map', 'true', 'false', 'satisfiable',
# sympy.assumptions
'AppliedPredicate', 'Predicate', 'AssumptionsContext', 'assuming', 'Q',
'ask', 'register_handler', 'remove_handler', 'refine',
# sympy.polys
'Poly', 'PurePoly', 'poly_from_expr', 'parallel_poly_from_expr', 'degree',
'total_degree', 'degree_list', 'LC', 'LM', 'LT', 'pdiv', 'prem', 'pquo',
'pexquo', 'div', 'rem', 'quo', 'exquo', 'half_gcdex', 'gcdex', 'invert',
'subresultants', 'resultant', 'discriminant', 'cofactors', 'gcd_list',
'gcd', 'lcm_list', 'lcm', 'terms_gcd', 'trunc', 'monic', 'content',
'primitive', 'compose', 'decompose', 'sturm', 'gff_list', 'gff',
'sqf_norm', 'sqf_part', 'sqf_list', 'sqf', 'factor_list', 'factor',
'intervals', 'refine_root', 'count_roots', 'all_roots', 'real_roots',
'nroots', 'ground_roots', 'nth_power_roots_poly', 'cancel', 'reduced',
'groebner', 'is_zero_dimensional', 'GroebnerBasis', 'poly', 'symmetrize',
'horner', 'interpolate', 'rational_interpolate', 'viete', 'together',
'BasePolynomialError', 'ExactQuotientFailed', 'PolynomialDivisionFailed',
'OperationNotSupported', 'HeuristicGCDFailed', 'HomomorphismFailed',
'IsomorphismFailed', 'ExtraneousFactors', 'EvaluationFailed',
'RefinementFailed', 'CoercionFailed', 'NotInvertible', 'NotReversible',
'NotAlgebraic', 'DomainError', 'PolynomialError', 'UnificationFailed',
'GeneratorsError', 'GeneratorsNeeded', 'ComputationFailed',
'UnivariatePolynomialError', 'MultivariatePolynomialError',
'PolificationFailed', 'OptionError', 'FlagError', 'minpoly',
'minimal_polynomial', 'primitive_element', 'field_isomorphism',
'to_number_field', 'isolate', 'round_two', 'prime_decomp',
'prime_valuation', 'galois_group', 'itermonomials', 'Monomial', 'lex', 'grlex',
'grevlex', 'ilex', 'igrlex', 'igrevlex', 'CRootOf', 'rootof', 'RootOf',
'ComplexRootOf', 'RootSum', 'roots', 'Domain', 'FiniteField',
'IntegerRing', 'RationalField', 'RealField', 'ComplexField',
'PythonFiniteField', 'GMPYFiniteField', 'PythonIntegerRing',
'GMPYIntegerRing', 'PythonRational', 'GMPYRationalField',
'AlgebraicField', 'PolynomialRing', 'FractionField', 'ExpressionDomain',
'FF_python', 'FF_gmpy', 'ZZ_python', 'ZZ_gmpy', 'QQ_python', 'QQ_gmpy',
'GF', 'FF', 'ZZ', 'QQ', 'ZZ_I', 'QQ_I', 'RR', 'CC', 'EX', 'EXRAW',
'construct_domain', 'swinnerton_dyer_poly', 'cyclotomic_poly',
'symmetric_poly', 'random_poly', 'interpolating_poly', 'jacobi_poly',
'chebyshevt_poly', 'chebyshevu_poly', 'hermite_poly', 'hermite_prob_poly',
'legendre_poly', 'laguerre_poly', 'apart', 'apart_list', 'assemble_partfrac_list',
'Options', 'ring', 'xring', 'vring', 'sring', 'field', 'xfield', 'vfield',
'sfield',
# sympy.series
'Order', 'O', 'limit', 'Limit', 'gruntz', 'series', 'approximants',
'residue', 'EmptySequence', 'SeqPer', 'SeqFormula', 'sequence', 'SeqAdd',
'SeqMul', 'fourier_series', 'fps', 'difference_delta', 'limit_seq',
# sympy.functions
'factorial', 'factorial2', 'rf', 'ff', 'binomial', 'RisingFactorial',
'FallingFactorial', 'subfactorial', 'carmichael', 'fibonacci', 'lucas',
'motzkin', 'tribonacci', 'harmonic', 'bernoulli', 'bell', 'euler', 'catalan',
'genocchi', 'andre', 'partition', 'divisor_sigma', 'legendre_symbol', 'jacobi_symbol',
'kronecker_symbol', 'mobius', 'primenu', 'primeomega', 'totient', 'primepi',
'reduced_totient', 'sqrt', 'root', 'Min', 'Max', 'Id', 'real_root',
'Rem', 'cbrt', 're', 'im', 'sign', 'Abs', 'conjugate', 'arg', 'polar_lift',
'periodic_argument', 'unbranched_argument', 'principal_branch',
'transpose', 'adjoint', 'polarify', 'unpolarify', 'sin', 'cos', 'tan',
'sec', 'csc', 'cot', 'sinc', 'asin', 'acos', 'atan', 'asec', 'acsc',
'acot', 'atan2', 'exp_polar', 'exp', 'ln', 'log', 'LambertW', 'sinh',
'cosh', 'tanh', 'coth', 'sech', 'csch', 'asinh', 'acosh', 'atanh',
'acoth', 'asech', 'acsch', 'floor', 'ceiling', 'frac', 'Piecewise',
'piecewise_fold', 'piecewise_exclusive', 'erf', 'erfc', 'erfi', 'erf2',
'erfinv', 'erfcinv', 'erf2inv', 'Ei', 'expint', 'E1', 'li', 'Li', 'Si',
'Ci', 'Shi', 'Chi', 'fresnels', 'fresnelc', 'gamma', 'lowergamma',
'uppergamma', 'polygamma', 'loggamma', 'digamma', 'trigamma', 'multigamma',
'dirichlet_eta', 'zeta', 'lerchphi', 'polylog', 'stieltjes', 'Eijk', 'LeviCivita',
'KroneckerDelta', 'SingularityFunction', 'DiracDelta', 'Heaviside',
'bspline_basis', 'bspline_basis_set', 'interpolating_spline', 'besselj',
'bessely', 'besseli', 'besselk', 'hankel1', 'hankel2', 'jn', 'yn',
'jn_zeros', 'hn1', 'hn2', 'airyai', 'airybi', 'airyaiprime',
'airybiprime', 'marcumq', 'hyper', 'meijerg', 'appellf1', 'legendre',
'assoc_legendre', 'hermite', 'hermite_prob', 'chebyshevt', 'chebyshevu',
'chebyshevu_root', 'chebyshevt_root', 'laguerre', 'assoc_laguerre',
'gegenbauer', 'jacobi', 'jacobi_normalized', 'Ynm', 'Ynm_c', 'Znm',
'elliptic_k', 'elliptic_f', 'elliptic_e', 'elliptic_pi', 'beta',
'mathieus', 'mathieuc', 'mathieusprime', 'mathieucprime', 'riemann_xi','betainc',
'betainc_regularized',
# sympy.ntheory
'nextprime', 'prevprime', 'prime', 'primerange', 'randprime',
'Sieve', 'sieve', 'primorial', 'cycle_length', 'composite', 'compositepi',
'isprime', 'divisors', 'proper_divisors', 'factorint', 'multiplicity',
'perfect_power', 'pollard_pm1', 'pollard_rho', 'primefactors',
'divisor_count', 'proper_divisor_count',
'factorrat',
'mersenne_prime_exponent', 'is_perfect', 'is_mersenne_prime',
'is_abundant', 'is_deficient', 'is_amicable', 'is_carmichael', 'abundance',
'npartitions',
'is_primitive_root', 'is_quad_residue',
'n_order', 'sqrt_mod', 'quadratic_residues',
'primitive_root', 'nthroot_mod', 'is_nthpow_residue', 'sqrt_mod_iter',
'discrete_log', 'quadratic_congruence', 'binomial_coefficients',
'binomial_coefficients_list', 'multinomial_coefficients',
'continued_fraction_periodic', 'continued_fraction_iterator',
'continued_fraction_reduce', 'continued_fraction_convergents',
'continued_fraction', 'egyptian_fraction',
# sympy.concrete
'product', 'Product', 'summation', 'Sum',
# sympy.discrete
'fft', 'ifft', 'ntt', 'intt', 'fwht', 'ifwht', 'mobius_transform',
'inverse_mobius_transform', 'convolution', 'covering_product',
'intersecting_product',
# sympy.simplify
'simplify', 'hypersimp', 'hypersimilar', 'logcombine', 'separatevars',
'posify', 'besselsimp', 'kroneckersimp', 'signsimp',
'nsimplify', 'FU', 'fu', 'sqrtdenest', 'cse', 'epath', 'EPath',
'hyperexpand', 'collect', 'rcollect', 'radsimp', 'collect_const',
'fraction', 'numer', 'denom', 'trigsimp', 'exptrigsimp', 'powsimp',
'powdenest', 'combsimp', 'gammasimp', 'ratsimp', 'ratsimpmodprime',
# sympy.sets
'Set', 'Interval', 'Union', 'EmptySet', 'FiniteSet', 'ProductSet',
'Intersection', 'imageset', 'DisjointUnion', 'Complement', 'SymmetricDifference',
'ImageSet', 'Range', 'ComplexRegion', 'Reals', 'Contains', 'ConditionSet',
'Ordinal', 'OmegaPower', 'ord0', 'PowerSet', 'Naturals',
'Naturals0', 'UniversalSet', 'Integers', 'Rationals', 'Complexes',
# sympy.solvers
'solve', 'solve_linear_system', 'solve_linear_system_LU',
'solve_undetermined_coeffs', 'nsolve', 'solve_linear', 'checksol',
'det_quick', 'inv_quick', 'check_assumptions', 'failing_assumptions',
'diophantine', 'rsolve', 'rsolve_poly', 'rsolve_ratio', 'rsolve_hyper',
'checkodesol', 'classify_ode', 'dsolve', 'homogeneous_order',
'solve_poly_system', 'solve_triangulated', 'pde_separate',
'pde_separate_add', 'pde_separate_mul', 'pdsolve', 'classify_pde',
'checkpdesol', 'ode_order', 'reduce_inequalities',
'reduce_abs_inequality', 'reduce_abs_inequalities',
'solve_poly_inequality', 'solve_rational_inequalities',
'solve_univariate_inequality', 'decompogen', 'solveset', 'linsolve',
'linear_eq_to_matrix', 'nonlinsolve', 'substitution',
# sympy.matrices
'ShapeError', 'NonSquareMatrixError', 'GramSchmidt', 'casoratian', 'diag',
'eye', 'hessian', 'jordan_cell', 'list2numpy', 'matrix2numpy',
'matrix_multiply_elementwise', 'ones', 'randMatrix', 'rot_axis1',
'rot_axis2', 'rot_axis3', 'symarray', 'wronskian', 'zeros',
'MutableDenseMatrix', 'DeferredVector', 'MatrixBase', 'Matrix',
'MutableMatrix', 'MutableSparseMatrix', 'banded', 'ImmutableDenseMatrix',
'ImmutableSparseMatrix', 'ImmutableMatrix', 'SparseMatrix', 'MatrixSlice',
'BlockDiagMatrix', 'BlockMatrix', 'FunctionMatrix', 'Identity', 'Inverse',
'MatAdd', 'MatMul', 'MatPow', 'MatrixExpr', 'MatrixSymbol', 'Trace',
'Transpose', 'ZeroMatrix', 'OneMatrix', 'blockcut', 'block_collapse',
'matrix_symbols', 'Adjoint', 'hadamard_product', 'HadamardProduct',
'HadamardPower', 'Determinant', 'det', 'diagonalize_vector', 'DiagMatrix',
'DiagonalMatrix', 'DiagonalOf', 'trace', 'DotProduct',
'kronecker_product', 'KroneckerProduct', 'PermutationMatrix',
'MatrixPermute', 'Permanent', 'per', 'rot_ccw_axis1', 'rot_ccw_axis2',
'rot_ccw_axis3', 'rot_givens',
# sympy.geometry
'Point', 'Point2D', 'Point3D', 'Line', 'Ray', 'Segment', 'Line2D',
'Segment2D', 'Ray2D', 'Line3D', 'Segment3D', 'Ray3D', 'Plane', 'Ellipse',
'Circle', 'Polygon', 'RegularPolygon', 'Triangle', 'rad', 'deg',
'are_similar', 'centroid', 'convex_hull', 'idiff', 'intersection',
'closest_points', 'farthest_points', 'GeometryError', 'Curve', 'Parabola',
# sympy.utilities
'flatten', 'group', 'take', 'subsets', 'variations', 'numbered_symbols',
'cartes', 'capture', 'dict_merge', 'prefixes', 'postfixes', 'sift',
'topological_sort', 'unflatten', 'has_dups', 'has_variety', 'reshape',
'rotations', 'filldedent', 'lambdify', 'threaded', 'xthreaded',
'public', 'memoize_property', 'timed',
# sympy.integrals
'integrate', 'Integral', 'line_integrate', 'mellin_transform',
'inverse_mellin_transform', 'MellinTransform', 'InverseMellinTransform',
'laplace_transform', 'inverse_laplace_transform', 'LaplaceTransform',
'laplace_correspondence', 'laplace_initial_conds',
'InverseLaplaceTransform', 'fourier_transform',
'inverse_fourier_transform', 'FourierTransform',
'InverseFourierTransform', 'sine_transform', 'inverse_sine_transform',
'SineTransform', 'InverseSineTransform', 'cosine_transform',
'inverse_cosine_transform', 'CosineTransform', 'InverseCosineTransform',
'hankel_transform', 'inverse_hankel_transform', 'HankelTransform',
'InverseHankelTransform', 'singularityintegrate',
# sympy.tensor
'IndexedBase', 'Idx', 'Indexed', 'get_contraction_structure',
'get_indices', 'shape', 'MutableDenseNDimArray', 'ImmutableDenseNDimArray',
'MutableSparseNDimArray', 'ImmutableSparseNDimArray', 'NDimArray',
'tensorproduct', 'tensorcontraction', 'tensordiagonal', 'derive_by_array',
'permutedims', 'Array', 'DenseNDimArray', 'SparseNDimArray',
# sympy.parsing
'parse_expr',
# sympy.calculus
'euler_equations', 'singularities', 'is_increasing',
'is_strictly_increasing', 'is_decreasing', 'is_strictly_decreasing',
'is_monotonic', 'finite_diff_weights', 'apply_finite_diff',
'differentiate_finite', 'periodicity', 'not_empty_in',
'AccumBounds', 'is_convex', 'stationary_points', 'minimum', 'maximum',
# sympy.algebras
'Quaternion',
# sympy.printing
'pager_print', 'pretty', 'pretty_print', 'pprint', 'pprint_use_unicode',
'pprint_try_use_unicode', 'latex', 'print_latex', 'multiline_latex',
'mathml', 'print_mathml', 'python', 'print_python', 'pycode', 'ccode',
'print_ccode', 'smtlib_code', 'glsl_code', 'print_glsl', 'cxxcode', 'fcode',
'print_fcode', 'rcode', 'print_rcode', 'jscode', 'print_jscode',
'julia_code', 'mathematica_code', 'octave_code', 'rust_code', 'print_gtk',
'preview', 'srepr', 'print_tree', 'StrPrinter', 'sstr', 'sstrrepr',
'TableForm', 'dotprint', 'maple_code', 'print_maple_code',
# sympy.plotting
'plot', 'textplot', 'plot_backends', 'plot_implicit', 'plot_parametric',
# sympy.interactive
'init_session', 'init_printing', 'interactive_traversal',
# sympy.testing
'test', 'doctest',
]
#===========================================================================#
# #
# XXX: The names below were importable before SymPy 1.6 using #
# #
# from sympy import * #
# #
# This happened implicitly because there was no __all__ defined in this #
# __init__.py file. Not every package is imported. The list matches what #
# would have been imported before. It is possible that these packages will #
# not be imported by a star-import from sympy in future. #
# #
#===========================================================================#
__all__.extend((
'algebras',
'assumptions',
'calculus',
'concrete',
'discrete',
'external',
'functions',
'geometry',
'interactive',
'multipledispatch',
'ntheory',
'parsing',
'plotting',
'polys',
'printing',
'release',
'strategies',
'tensor',
'utilities',
))
PK ]ZZZ]�;ä � sympy/abc.py"""
This module exports all latin and greek letters as Symbols, so you can
conveniently do
>>> from sympy.abc import x, y
instead of the slightly more clunky-looking
>>> from sympy import symbols
>>> x, y = symbols('x y')
Caveats
=======
1. As of the time of writing this, the names ``O``, ``S``, ``I``, ``N``,
``E``, and ``Q`` are colliding with names defined in SymPy. If you import them
from both ``sympy.abc`` and ``sympy``, the second import will "win".
This is an issue only for * imports, which should only be used for short-lived
code such as interactive sessions and throwaway scripts that do not survive
until the next SymPy upgrade, where ``sympy`` may contain a different set of
names.
2. This module does not define symbol names on demand, i.e.
``from sympy.abc import foo`` will be reported as an error because
``sympy.abc`` does not contain the name ``foo``. To get a symbol named ``foo``,
you still need to use ``Symbol('foo')`` or ``symbols('foo')``.
You can freely mix usage of ``sympy.abc`` and ``Symbol``/``symbols``, though
sticking with one and only one way to get the symbols does tend to make the code
more readable.
The module also defines some special names to help detect which names clash
with the default SymPy namespace.
``_clash1`` defines all the single letter variables that clash with
SymPy objects; ``_clash2`` defines the multi-letter clashing symbols;
and ``_clash`` is the union of both. These can be passed for ``locals``
during sympification if one desires Symbols rather than the non-Symbol
objects for those names.
Examples
========
>>> from sympy import S
>>> from sympy.abc import _clash1, _clash2, _clash
>>> S("Q & C", locals=_clash1)
C & Q
>>> S('pi(x)', locals=_clash2)
pi(x)
>>> S('pi(C, Q)', locals=_clash)
pi(C, Q)
"""
from typing import Any, Dict as tDict
import string
from .core import Symbol, symbols
from .core.alphabets import greeks
from sympy.parsing.sympy_parser import null
##### Symbol definitions #####
# Implementation note: The easiest way to avoid typos in the symbols()
# parameter is to copy it from the left-hand side of the assignment.
a, b, c, d, e, f, g, h, i, j = symbols('a, b, c, d, e, f, g, h, i, j')
k, l, m, n, o, p, q, r, s, t = symbols('k, l, m, n, o, p, q, r, s, t')
u, v, w, x, y, z = symbols('u, v, w, x, y, z')
A, B, C, D, E, F, G, H, I, J = symbols('A, B, C, D, E, F, G, H, I, J')
K, L, M, N, O, P, Q, R, S, T = symbols('K, L, M, N, O, P, Q, R, S, T')
U, V, W, X, Y, Z = symbols('U, V, W, X, Y, Z')
alpha, beta, gamma, delta = symbols('alpha, beta, gamma, delta')
epsilon, zeta, eta, theta = symbols('epsilon, zeta, eta, theta')
iota, kappa, lamda, mu = symbols('iota, kappa, lamda, mu')
nu, xi, omicron, pi = symbols('nu, xi, omicron, pi')
rho, sigma, tau, upsilon = symbols('rho, sigma, tau, upsilon')
phi, chi, psi, omega = symbols('phi, chi, psi, omega')
##### Clashing-symbols diagnostics #####
# We want to know which names in SymPy collide with those in here.
# This is mostly for diagnosing SymPy's namespace during SymPy development.
_latin = list(string.ascii_letters)
# QOSINE should not be imported as they clash; gamma, pi and zeta clash, too
_greek = list(greeks) # make a copy, so we can mutate it
# Note: We import lamda since lambda is a reserved keyword in Python
_greek.remove("lambda")
_greek.append("lamda")
ns: tDict[str, Any] = {}
exec('from sympy import *', ns)
_clash1: tDict[str, Any] = {}
_clash2: tDict[str, Any] = {}
while ns:
_k, _ = ns.popitem()
if _k in _greek:
_clash2[_k] = null
_greek.remove(_k)
elif _k in _latin:
_clash1[_k] = null
_latin.remove(_k)
_clash = {}
_clash.update(_clash1)
_clash.update(_clash2)
del _latin, _greek, Symbol, _k, null
PK ]ZZZ�@��{ { sympy/galgebra.pyraise ImportError("""As of SymPy 1.0 the galgebra module is maintained separately at https://github.com/pygae/galgebra""")
PK ]ZZZ�q� sympy/release.py__version__ = "1.13.3"
PK ]ZZZ>��& &
sympy/this.py"""
The Zen of SymPy.
"""
s = """The Zen of SymPy
Unevaluated is better than evaluated.
The user interface matters.
Printing matters.
Pure Python can be fast enough.
If it's too slow, it's (probably) your fault.
Documentation matters.
Correctness is more important than speed.
Push it in now and improve upon it later.
Coverage by testing matters.
Smart tests are better than random tests.
But random tests sometimes find what your smartest test missed.
The Python way is probably the right way.
Community is more important than code."""
print(s)
PK ]ZZZB���> > sympy/algebras/__init__.pyfrom .quaternion import Quaternion
__all__ = ["Quaternion",]
PK ]ZZZ=/y�� �� sympy/algebras/quaternion.pyfrom sympy.core.numbers import Rational
from sympy.core.singleton import S
from sympy.core.relational import is_eq
from sympy.functions.elementary.complexes import (conjugate, im, re, sign)
from sympy.functions.elementary.exponential import (exp, log as ln)
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.elementary.trigonometric import (acos, asin, atan2)
from sympy.functions.elementary.trigonometric import (cos, sin)
from sympy.simplify.trigsimp import trigsimp
from sympy.integrals.integrals import integrate
from sympy.matrices.dense import MutableDenseMatrix as Matrix
from sympy.core.sympify import sympify, _sympify
from sympy.core.expr import Expr
from sympy.core.logic import fuzzy_not, fuzzy_or
from sympy.utilities.misc import as_int
from mpmath.libmp.libmpf import prec_to_dps
def _check_norm(elements, norm):
"""validate if input norm is consistent"""
if norm is not None and norm.is_number:
if norm.is_positive is False:
raise ValueError("Input norm must be positive.")
numerical = all(i.is_number and i.is_real is True for i in elements)
if numerical and is_eq(norm**2, sum(i**2 for i in elements)) is False:
raise ValueError("Incompatible value for norm.")
def _is_extrinsic(seq):
"""validate seq and return True if seq is lowercase and False if uppercase"""
if type(seq) != str:
raise ValueError('Expected seq to be a string.')
if len(seq) != 3:
raise ValueError("Expected 3 axes, got `{}`.".format(seq))
intrinsic = seq.isupper()
extrinsic = seq.islower()
if not (intrinsic or extrinsic):
raise ValueError("seq must either be fully uppercase (for extrinsic "
"rotations), or fully lowercase, for intrinsic "
"rotations).")
i, j, k = seq.lower()
if (i == j) or (j == k):
raise ValueError("Consecutive axes must be different")
bad = set(seq) - set('xyzXYZ')
if bad:
raise ValueError("Expected axes from `seq` to be from "
"['x', 'y', 'z'] or ['X', 'Y', 'Z'], "
"got {}".format(''.join(bad)))
return extrinsic
class Quaternion(Expr):
"""Provides basic quaternion operations.
Quaternion objects can be instantiated as ``Quaternion(a, b, c, d)``
as in $q = a + bi + cj + dk$.
Parameters
==========
norm : None or number
Pre-defined quaternion norm. If a value is given, Quaternion.norm
returns this pre-defined value instead of calculating the norm
Examples
========
>>> from sympy import Quaternion
>>> q = Quaternion(1, 2, 3, 4)
>>> q
1 + 2*i + 3*j + 4*k
Quaternions over complex fields can be defined as:
>>> from sympy import Quaternion
>>> from sympy import symbols, I
>>> x = symbols('x')
>>> q1 = Quaternion(x, x**3, x, x**2, real_field = False)
>>> q2 = Quaternion(3 + 4*I, 2 + 5*I, 0, 7 + 8*I, real_field = False)
>>> q1
x + x**3*i + x*j + x**2*k
>>> q2
(3 + 4*I) + (2 + 5*I)*i + 0*j + (7 + 8*I)*k
Defining symbolic unit quaternions:
>>> from sympy import Quaternion
>>> from sympy.abc import w, x, y, z
>>> q = Quaternion(w, x, y, z, norm=1)
>>> q
w + x*i + y*j + z*k
>>> q.norm()
1
References
==========
.. [1] https://www.euclideanspace.com/maths/algebra/realNormedAlgebra/quaternions/
.. [2] https://en.wikipedia.org/wiki/Quaternion
"""
_op_priority = 11.0
is_commutative = False
def __new__(cls, a=0, b=0, c=0, d=0, real_field=True, norm=None):
a, b, c, d = map(sympify, (a, b, c, d))
if any(i.is_commutative is False for i in [a, b, c, d]):
raise ValueError("arguments have to be commutative")
obj = super().__new__(cls, a, b, c, d)
obj._real_field = real_field
obj.set_norm(norm)
return obj
def set_norm(self, norm):
"""Sets norm of an already instantiated quaternion.
Parameters
==========
norm : None or number
Pre-defined quaternion norm. If a value is given, Quaternion.norm
returns this pre-defined value instead of calculating the norm
Examples
========
>>> from sympy import Quaternion
>>> from sympy.abc import a, b, c, d
>>> q = Quaternion(a, b, c, d)
>>> q.norm()
sqrt(a**2 + b**2 + c**2 + d**2)
Setting the norm:
>>> q.set_norm(1)
>>> q.norm()
1
Removing set norm:
>>> q.set_norm(None)
>>> q.norm()
sqrt(a**2 + b**2 + c**2 + d**2)
"""
norm = sympify(norm)
_check_norm(self.args, norm)
self._norm = norm
@property
def a(self):
return self.args[0]
@property
def b(self):
return self.args[1]
@property
def c(self):
return self.args[2]
@property
def d(self):
return self.args[3]
@property
def real_field(self):
return self._real_field
@property
def product_matrix_left(self):
r"""Returns 4 x 4 Matrix equivalent to a Hamilton product from the
left. This can be useful when treating quaternion elements as column
vectors. Given a quaternion $q = a + bi + cj + dk$ where a, b, c and d
are real numbers, the product matrix from the left is:
.. math::
M = \begin{bmatrix} a &-b &-c &-d \\
b & a &-d & c \\
c & d & a &-b \\
d &-c & b & a \end{bmatrix}
Examples
========
>>> from sympy import Quaternion
>>> from sympy.abc import a, b, c, d
>>> q1 = Quaternion(1, 0, 0, 1)
>>> q2 = Quaternion(a, b, c, d)
>>> q1.product_matrix_left
Matrix([
[1, 0, 0, -1],
[0, 1, -1, 0],
[0, 1, 1, 0],
[1, 0, 0, 1]])
>>> q1.product_matrix_left * q2.to_Matrix()
Matrix([
[a - d],
[b - c],
[b + c],
[a + d]])
This is equivalent to:
>>> (q1 * q2).to_Matrix()
Matrix([
[a - d],
[b - c],
[b + c],
[a + d]])
"""
return Matrix([
[self.a, -self.b, -self.c, -self.d],
[self.b, self.a, -self.d, self.c],
[self.c, self.d, self.a, -self.b],
[self.d, -self.c, self.b, self.a]])
@property
def product_matrix_right(self):
r"""Returns 4 x 4 Matrix equivalent to a Hamilton product from the
right. This can be useful when treating quaternion elements as column
vectors. Given a quaternion $q = a + bi + cj + dk$ where a, b, c and d
are real numbers, the product matrix from the left is:
.. math::
M = \begin{bmatrix} a &-b &-c &-d \\
b & a & d &-c \\
c &-d & a & b \\
d & c &-b & a \end{bmatrix}
Examples
========
>>> from sympy import Quaternion
>>> from sympy.abc import a, b, c, d
>>> q1 = Quaternion(a, b, c, d)
>>> q2 = Quaternion(1, 0, 0, 1)
>>> q2.product_matrix_right
Matrix([
[1, 0, 0, -1],
[0, 1, 1, 0],
[0, -1, 1, 0],
[1, 0, 0, 1]])
Note the switched arguments: the matrix represents the quaternion on
the right, but is still considered as a matrix multiplication from the
left.
>>> q2.product_matrix_right * q1.to_Matrix()
Matrix([
[ a - d],
[ b + c],
[-b + c],
[ a + d]])
This is equivalent to:
>>> (q1 * q2).to_Matrix()
Matrix([
[ a - d],
[ b + c],
[-b + c],
[ a + d]])
"""
return Matrix([
[self.a, -self.b, -self.c, -self.d],
[self.b, self.a, self.d, -self.c],
[self.c, -self.d, self.a, self.b],
[self.d, self.c, -self.b, self.a]])
def to_Matrix(self, vector_only=False):
"""Returns elements of quaternion as a column vector.
By default, a ``Matrix`` of length 4 is returned, with the real part as the
first element.
If ``vector_only`` is ``True``, returns only imaginary part as a Matrix of
length 3.
Parameters
==========
vector_only : bool
If True, only imaginary part is returned.
Default value: False
Returns
=======
Matrix
A column vector constructed by the elements of the quaternion.
Examples
========
>>> from sympy import Quaternion
>>> from sympy.abc import a, b, c, d
>>> q = Quaternion(a, b, c, d)
>>> q
a + b*i + c*j + d*k
>>> q.to_Matrix()
Matrix([
[a],
[b],
[c],
[d]])
>>> q.to_Matrix(vector_only=True)
Matrix([
[b],
[c],
[d]])
"""
if vector_only:
return Matrix(self.args[1:])
else:
return Matrix(self.args)
@classmethod
def from_Matrix(cls, elements):
"""Returns quaternion from elements of a column vector`.
If vector_only is True, returns only imaginary part as a Matrix of
length 3.
Parameters
==========
elements : Matrix, list or tuple of length 3 or 4. If length is 3,
assume real part is zero.
Default value: False
Returns
=======
Quaternion
A quaternion created from the input elements.
Examples
========
>>> from sympy import Quaternion
>>> from sympy.abc import a, b, c, d
>>> q = Quaternion.from_Matrix([a, b, c, d])
>>> q
a + b*i + c*j + d*k
>>> q = Quaternion.from_Matrix([b, c, d])
>>> q
0 + b*i + c*j + d*k
"""
length = len(elements)
if length != 3 and length != 4:
raise ValueError("Input elements must have length 3 or 4, got {} "
"elements".format(length))
if length == 3:
return Quaternion(0, *elements)
else:
return Quaternion(*elements)
@classmethod
def from_euler(cls, angles, seq):
"""Returns quaternion equivalent to rotation represented by the Euler
angles, in the sequence defined by ``seq``.
Parameters
==========
angles : list, tuple or Matrix of 3 numbers
The Euler angles (in radians).
seq : string of length 3
Represents the sequence of rotations.
For extrinsic rotations, seq must be all lowercase and its elements
must be from the set ``{'x', 'y', 'z'}``
For intrinsic rotations, seq must be all uppercase and its elements
must be from the set ``{'X', 'Y', 'Z'}``
Returns
=======
Quaternion
The normalized rotation quaternion calculated from the Euler angles
in the given sequence.
Examples
========
>>> from sympy import Quaternion
>>> from sympy import pi
>>> q = Quaternion.from_euler([pi/2, 0, 0], 'xyz')
>>> q
sqrt(2)/2 + sqrt(2)/2*i + 0*j + 0*k
>>> q = Quaternion.from_euler([0, pi/2, pi] , 'zyz')
>>> q
0 + (-sqrt(2)/2)*i + 0*j + sqrt(2)/2*k
>>> q = Quaternion.from_euler([0, pi/2, pi] , 'ZYZ')
>>> q
0 + sqrt(2)/2*i + 0*j + sqrt(2)/2*k
"""
if len(angles) != 3:
raise ValueError("3 angles must be given.")
extrinsic = _is_extrinsic(seq)
i, j, k = seq.lower()
# get elementary basis vectors
ei = [1 if n == i else 0 for n in 'xyz']
ej = [1 if n == j else 0 for n in 'xyz']
ek = [1 if n == k else 0 for n in 'xyz']
# calculate distinct quaternions
qi = cls.from_axis_angle(ei, angles[0])
qj = cls.from_axis_angle(ej, angles[1])
qk = cls.from_axis_angle(ek, angles[2])
if extrinsic:
return trigsimp(qk * qj * qi)
else:
return trigsimp(qi * qj * qk)
def to_euler(self, seq, angle_addition=True, avoid_square_root=False):
r"""Returns Euler angles representing same rotation as the quaternion,
in the sequence given by ``seq``. This implements the method described
in [1]_.
For degenerate cases (gymbal lock cases), the third angle is
set to zero.
Parameters
==========
seq : string of length 3
Represents the sequence of rotations.
For extrinsic rotations, seq must be all lowercase and its elements
must be from the set ``{'x', 'y', 'z'}``
For intrinsic rotations, seq must be all uppercase and its elements
must be from the set ``{'X', 'Y', 'Z'}``
angle_addition : bool
When True, first and third angles are given as an addition and
subtraction of two simpler ``atan2`` expressions. When False, the
first and third angles are each given by a single more complicated
``atan2`` expression. This equivalent expression is given by:
.. math::
\operatorname{atan_2} (b,a) \pm \operatorname{atan_2} (d,c) =
\operatorname{atan_2} (bc\pm ad, ac\mp bd)
Default value: True
avoid_square_root : bool
When True, the second angle is calculated with an expression based
on ``acos``, which is slightly more complicated but avoids a square
root. When False, second angle is calculated with ``atan2``, which
is simpler and can be better for numerical reasons (some
numerical implementations of ``acos`` have problems near zero).
Default value: False
Returns
=======
Tuple
The Euler angles calculated from the quaternion
Examples
========
>>> from sympy import Quaternion
>>> from sympy.abc import a, b, c, d
>>> euler = Quaternion(a, b, c, d).to_euler('zyz')
>>> euler
(-atan2(-b, c) + atan2(d, a),
2*atan2(sqrt(b**2 + c**2), sqrt(a**2 + d**2)),
atan2(-b, c) + atan2(d, a))
References
==========
.. [1] https://doi.org/10.1371/journal.pone.0276302
"""
if self.is_zero_quaternion():
raise ValueError('Cannot convert a quaternion with norm 0.')
angles = [0, 0, 0]
extrinsic = _is_extrinsic(seq)
i, j, k = seq.lower()
# get index corresponding to elementary basis vectors
i = 'xyz'.index(i) + 1
j = 'xyz'.index(j) + 1
k = 'xyz'.index(k) + 1
if not extrinsic:
i, k = k, i
# check if sequence is symmetric
symmetric = i == k
if symmetric:
k = 6 - i - j
# parity of the permutation
sign = (i - j) * (j - k) * (k - i) // 2
# permutate elements
elements = [self.a, self.b, self.c, self.d]
a = elements[0]
b = elements[i]
c = elements[j]
d = elements[k] * sign
if not symmetric:
a, b, c, d = a - c, b + d, c + a, d - b
if avoid_square_root:
if symmetric:
n2 = self.norm()**2
angles[1] = acos((a * a + b * b - c * c - d * d) / n2)
else:
n2 = 2 * self.norm()**2
angles[1] = asin((c * c + d * d - a * a - b * b) / n2)
else:
angles[1] = 2 * atan2(sqrt(c * c + d * d), sqrt(a * a + b * b))
if not symmetric:
angles[1] -= S.Pi / 2
# Check for singularities in numerical cases
case = 0
if is_eq(c, S.Zero) and is_eq(d, S.Zero):
case = 1
if is_eq(a, S.Zero) and is_eq(b, S.Zero):
case = 2
if case == 0:
if angle_addition:
angles[0] = atan2(b, a) + atan2(d, c)
angles[2] = atan2(b, a) - atan2(d, c)
else:
angles[0] = atan2(b*c + a*d, a*c - b*d)
angles[2] = atan2(b*c - a*d, a*c + b*d)
else: # any degenerate case
angles[2 * (not extrinsic)] = S.Zero
if case == 1:
angles[2 * extrinsic] = 2 * atan2(b, a)
else:
angles[2 * extrinsic] = 2 * atan2(d, c)
angles[2 * extrinsic] *= (-1 if extrinsic else 1)
# for Tait-Bryan angles
if not symmetric:
angles[0] *= sign
if extrinsic:
return tuple(angles[::-1])
else:
return tuple(angles)
@classmethod
def from_axis_angle(cls, vector, angle):
"""Returns a rotation quaternion given the axis and the angle of rotation.
Parameters
==========
vector : tuple of three numbers
The vector representation of the given axis.
angle : number
The angle by which axis is rotated (in radians).
Returns
=======
Quaternion
The normalized rotation quaternion calculated from the given axis and the angle of rotation.
Examples
========
>>> from sympy import Quaternion
>>> from sympy import pi, sqrt
>>> q = Quaternion.from_axis_angle((sqrt(3)/3, sqrt(3)/3, sqrt(3)/3), 2*pi/3)
>>> q
1/2 + 1/2*i + 1/2*j + 1/2*k
"""
(x, y, z) = vector
norm = sqrt(x**2 + y**2 + z**2)
(x, y, z) = (x / norm, y / norm, z / norm)
s = sin(angle * S.Half)
a = cos(angle * S.Half)
b = x * s
c = y * s
d = z * s
# note that this quaternion is already normalized by construction:
# c^2 + (s*x)^2 + (s*y)^2 + (s*z)^2 = c^2 + s^2*(x^2 + y^2 + z^2) = c^2 + s^2 * 1 = c^2 + s^2 = 1
# so, what we return is a normalized quaternion
return cls(a, b, c, d)
@classmethod
def from_rotation_matrix(cls, M):
"""Returns the equivalent quaternion of a matrix. The quaternion will be normalized
only if the matrix is special orthogonal (orthogonal and det(M) = 1).
Parameters
==========
M : Matrix
Input matrix to be converted to equivalent quaternion. M must be special
orthogonal (orthogonal and det(M) = 1) for the quaternion to be normalized.
Returns
=======
Quaternion
The quaternion equivalent to given matrix.
Examples
========
>>> from sympy import Quaternion
>>> from sympy import Matrix, symbols, cos, sin, trigsimp
>>> x = symbols('x')
>>> M = Matrix([[cos(x), -sin(x), 0], [sin(x), cos(x), 0], [0, 0, 1]])
>>> q = trigsimp(Quaternion.from_rotation_matrix(M))
>>> q
sqrt(2)*sqrt(cos(x) + 1)/2 + 0*i + 0*j + sqrt(2 - 2*cos(x))*sign(sin(x))/2*k
"""
absQ = M.det()**Rational(1, 3)
a = sqrt(absQ + M[0, 0] + M[1, 1] + M[2, 2]) / 2
b = sqrt(absQ + M[0, 0] - M[1, 1] - M[2, 2]) / 2
c = sqrt(absQ - M[0, 0] + M[1, 1] - M[2, 2]) / 2
d = sqrt(absQ - M[0, 0] - M[1, 1] + M[2, 2]) / 2
b = b * sign(M[2, 1] - M[1, 2])
c = c * sign(M[0, 2] - M[2, 0])
d = d * sign(M[1, 0] - M[0, 1])
return Quaternion(a, b, c, d)
def __add__(self, other):
return self.add(other)
def __radd__(self, other):
return self.add(other)
def __sub__(self, other):
return self.add(other*-1)
def __mul__(self, other):
return self._generic_mul(self, _sympify(other))
def __rmul__(self, other):
return self._generic_mul(_sympify(other), self)
def __pow__(self, p):
return self.pow(p)
def __neg__(self):
return Quaternion(-self.a, -self.b, -self.c, -self.d)
def __truediv__(self, other):
return self * sympify(other)**-1
def __rtruediv__(self, other):
return sympify(other) * self**-1
def _eval_Integral(self, *args):
return self.integrate(*args)
def diff(self, *symbols, **kwargs):
kwargs.setdefault('evaluate', True)
return self.func(*[a.diff(*symbols, **kwargs) for a in self.args])
def add(self, other):
"""Adds quaternions.
Parameters
==========
other : Quaternion
The quaternion to add to current (self) quaternion.
Returns
=======
Quaternion
The resultant quaternion after adding self to other
Examples
========
>>> from sympy import Quaternion
>>> from sympy import symbols
>>> q1 = Quaternion(1, 2, 3, 4)
>>> q2 = Quaternion(5, 6, 7, 8)
>>> q1.add(q2)
6 + 8*i + 10*j + 12*k
>>> q1 + 5
6 + 2*i + 3*j + 4*k
>>> x = symbols('x', real = True)
>>> q1.add(x)
(x + 1) + 2*i + 3*j + 4*k
Quaternions over complex fields :
>>> from sympy import Quaternion
>>> from sympy import I
>>> q3 = Quaternion(3 + 4*I, 2 + 5*I, 0, 7 + 8*I, real_field = False)
>>> q3.add(2 + 3*I)
(5 + 7*I) + (2 + 5*I)*i + 0*j + (7 + 8*I)*k
"""
q1 = self
q2 = sympify(other)
# If q2 is a number or a SymPy expression instead of a quaternion
if not isinstance(q2, Quaternion):
if q1.real_field and q2.is_complex:
return Quaternion(re(q2) + q1.a, im(q2) + q1.b, q1.c, q1.d)
elif q2.is_commutative:
return Quaternion(q1.a + q2, q1.b, q1.c, q1.d)
else:
raise ValueError("Only commutative expressions can be added with a Quaternion.")
return Quaternion(q1.a + q2.a, q1.b + q2.b, q1.c + q2.c, q1.d
+ q2.d)
def mul(self, other):
"""Multiplies quaternions.
Parameters
==========
other : Quaternion or symbol
The quaternion to multiply to current (self) quaternion.
Returns
=======
Quaternion
The resultant quaternion after multiplying self with other
Examples
========
>>> from sympy import Quaternion
>>> from sympy import symbols
>>> q1 = Quaternion(1, 2, 3, 4)
>>> q2 = Quaternion(5, 6, 7, 8)
>>> q1.mul(q2)
(-60) + 12*i + 30*j + 24*k
>>> q1.mul(2)
2 + 4*i + 6*j + 8*k
>>> x = symbols('x', real = True)
>>> q1.mul(x)
x + 2*x*i + 3*x*j + 4*x*k
Quaternions over complex fields :
>>> from sympy import Quaternion
>>> from sympy import I
>>> q3 = Quaternion(3 + 4*I, 2 + 5*I, 0, 7 + 8*I, real_field = False)
>>> q3.mul(2 + 3*I)
(2 + 3*I)*(3 + 4*I) + (2 + 3*I)*(2 + 5*I)*i + 0*j + (2 + 3*I)*(7 + 8*I)*k
"""
return self._generic_mul(self, _sympify(other))
@staticmethod
def _generic_mul(q1, q2):
"""Generic multiplication.
Parameters
==========
q1 : Quaternion or symbol
q2 : Quaternion or symbol
It is important to note that if neither q1 nor q2 is a Quaternion,
this function simply returns q1 * q2.
Returns
=======
Quaternion
The resultant quaternion after multiplying q1 and q2
Examples
========
>>> from sympy import Quaternion
>>> from sympy import Symbol, S
>>> q1 = Quaternion(1, 2, 3, 4)
>>> q2 = Quaternion(5, 6, 7, 8)
>>> Quaternion._generic_mul(q1, q2)
(-60) + 12*i + 30*j + 24*k
>>> Quaternion._generic_mul(q1, S(2))
2 + 4*i + 6*j + 8*k
>>> x = Symbol('x', real = True)
>>> Quaternion._generic_mul(q1, x)
x + 2*x*i + 3*x*j + 4*x*k
Quaternions over complex fields :
>>> from sympy import I
>>> q3 = Quaternion(3 + 4*I, 2 + 5*I, 0, 7 + 8*I, real_field = False)
>>> Quaternion._generic_mul(q3, 2 + 3*I)
(2 + 3*I)*(3 + 4*I) + (2 + 3*I)*(2 + 5*I)*i + 0*j + (2 + 3*I)*(7 + 8*I)*k
"""
# None is a Quaternion:
if not isinstance(q1, Quaternion) and not isinstance(q2, Quaternion):
return q1 * q2
# If q1 is a number or a SymPy expression instead of a quaternion
if not isinstance(q1, Quaternion):
if q2.real_field and q1.is_complex:
return Quaternion(re(q1), im(q1), 0, 0) * q2
elif q1.is_commutative:
return Quaternion(q1 * q2.a, q1 * q2.b, q1 * q2.c, q1 * q2.d)
else:
raise ValueError("Only commutative expressions can be multiplied with a Quaternion.")
# If q2 is a number or a SymPy expression instead of a quaternion
if not isinstance(q2, Quaternion):
if q1.real_field and q2.is_complex:
return q1 * Quaternion(re(q2), im(q2), 0, 0)
elif q2.is_commutative:
return Quaternion(q2 * q1.a, q2 * q1.b, q2 * q1.c, q2 * q1.d)
else:
raise ValueError("Only commutative expressions can be multiplied with a Quaternion.")
# If any of the quaternions has a fixed norm, pre-compute norm
if q1._norm is None and q2._norm is None:
norm = None
else:
norm = q1.norm() * q2.norm()
return Quaternion(-q1.b*q2.b - q1.c*q2.c - q1.d*q2.d + q1.a*q2.a,
q1.b*q2.a + q1.c*q2.d - q1.d*q2.c + q1.a*q2.b,
-q1.b*q2.d + q1.c*q2.a + q1.d*q2.b + q1.a*q2.c,
q1.b*q2.c - q1.c*q2.b + q1.d*q2.a + q1.a * q2.d,
norm=norm)
def _eval_conjugate(self):
"""Returns the conjugate of the quaternion."""
q = self
return Quaternion(q.a, -q.b, -q.c, -q.d, norm=q._norm)
def norm(self):
"""Returns the norm of the quaternion."""
if self._norm is None: # check if norm is pre-defined
q = self
# trigsimp is used to simplify sin(x)^2 + cos(x)^2 (these terms
# arise when from_axis_angle is used).
return sqrt(trigsimp(q.a**2 + q.b**2 + q.c**2 + q.d**2))
return self._norm
def normalize(self):
"""Returns the normalized form of the quaternion."""
q = self
return q * (1/q.norm())
def inverse(self):
"""Returns the inverse of the quaternion."""
q = self
if not q.norm():
raise ValueError("Cannot compute inverse for a quaternion with zero norm")
return conjugate(q) * (1/q.norm()**2)
def pow(self, p):
"""Finds the pth power of the quaternion.
Parameters
==========
p : int
Power to be applied on quaternion.
Returns
=======
Quaternion
Returns the p-th power of the current quaternion.
Returns the inverse if p = -1.
Examples
========
>>> from sympy import Quaternion
>>> q = Quaternion(1, 2, 3, 4)
>>> q.pow(4)
668 + (-224)*i + (-336)*j + (-448)*k
"""
try:
q, p = self, as_int(p)
except ValueError:
return NotImplemented
if p < 0:
q, p = q.inverse(), -p
if p == 1:
return q
res = Quaternion(1, 0, 0, 0)
while p > 0:
if p & 1:
res *= q
q *= q
p >>= 1
return res
def exp(self):
"""Returns the exponential of $q$, given by $e^q$.
Returns
=======
Quaternion
The exponential of the quaternion.
Examples
========
>>> from sympy import Quaternion
>>> q = Quaternion(1, 2, 3, 4)
>>> q.exp()
E*cos(sqrt(29))
+ 2*sqrt(29)*E*sin(sqrt(29))/29*i
+ 3*sqrt(29)*E*sin(sqrt(29))/29*j
+ 4*sqrt(29)*E*sin(sqrt(29))/29*k
"""
# exp(q) = e^a(cos||v|| + v/||v||*sin||v||)
q = self
vector_norm = sqrt(q.b**2 + q.c**2 + q.d**2)
a = exp(q.a) * cos(vector_norm)
b = exp(q.a) * sin(vector_norm) * q.b / vector_norm
c = exp(q.a) * sin(vector_norm) * q.c / vector_norm
d = exp(q.a) * sin(vector_norm) * q.d / vector_norm
return Quaternion(a, b, c, d)
def log(self):
r"""Returns the logarithm of the quaternion, given by $\log q$.
Examples
========
>>> from sympy import Quaternion
>>> q = Quaternion(1, 2, 3, 4)
>>> q.log()
log(sqrt(30))
+ 2*sqrt(29)*acos(sqrt(30)/30)/29*i
+ 3*sqrt(29)*acos(sqrt(30)/30)/29*j
+ 4*sqrt(29)*acos(sqrt(30)/30)/29*k
"""
# log(q) = log||q|| + v/||v||*arccos(a/||q||)
q = self
vector_norm = sqrt(q.b**2 + q.c**2 + q.d**2)
q_norm = q.norm()
a = ln(q_norm)
b = q.b * acos(q.a / q_norm) / vector_norm
c = q.c * acos(q.a / q_norm) / vector_norm
d = q.d * acos(q.a / q_norm) / vector_norm
return Quaternion(a, b, c, d)
def _eval_subs(self, *args):
elements = [i.subs(*args) for i in self.args]
norm = self._norm
if norm is not None:
norm = norm.subs(*args)
_check_norm(elements, norm)
return Quaternion(*elements, norm=norm)
def _eval_evalf(self, prec):
"""Returns the floating point approximations (decimal numbers) of the quaternion.
Returns
=======
Quaternion
Floating point approximations of quaternion(self)
Examples
========
>>> from sympy import Quaternion
>>> from sympy import sqrt
>>> q = Quaternion(1/sqrt(1), 1/sqrt(2), 1/sqrt(3), 1/sqrt(4))
>>> q.evalf()
1.00000000000000
+ 0.707106781186547*i
+ 0.577350269189626*j
+ 0.500000000000000*k
"""
nprec = prec_to_dps(prec)
return Quaternion(*[arg.evalf(n=nprec) for arg in self.args])
def pow_cos_sin(self, p):
"""Computes the pth power in the cos-sin form.
Parameters
==========
p : int
Power to be applied on quaternion.
Returns
=======
Quaternion
The p-th power in the cos-sin form.
Examples
========
>>> from sympy import Quaternion
>>> q = Quaternion(1, 2, 3, 4)
>>> q.pow_cos_sin(4)
900*cos(4*acos(sqrt(30)/30))
+ 1800*sqrt(29)*sin(4*acos(sqrt(30)/30))/29*i
+ 2700*sqrt(29)*sin(4*acos(sqrt(30)/30))/29*j
+ 3600*sqrt(29)*sin(4*acos(sqrt(30)/30))/29*k
"""
# q = ||q||*(cos(a) + u*sin(a))
# q^p = ||q||^p * (cos(p*a) + u*sin(p*a))
q = self
(v, angle) = q.to_axis_angle()
q2 = Quaternion.from_axis_angle(v, p * angle)
return q2 * (q.norm()**p)
def integrate(self, *args):
"""Computes integration of quaternion.
Returns
=======
Quaternion
Integration of the quaternion(self) with the given variable.
Examples
========
Indefinite Integral of quaternion :
>>> from sympy import Quaternion
>>> from sympy.abc import x
>>> q = Quaternion(1, 2, 3, 4)
>>> q.integrate(x)
x + 2*x*i + 3*x*j + 4*x*k
Definite integral of quaternion :
>>> from sympy import Quaternion
>>> from sympy.abc import x
>>> q = Quaternion(1, 2, 3, 4)
>>> q.integrate((x, 1, 5))
4 + 8*i + 12*j + 16*k
"""
# TODO: is this expression correct?
return Quaternion(integrate(self.a, *args), integrate(self.b, *args),
integrate(self.c, *args), integrate(self.d, *args))
@staticmethod
def rotate_point(pin, r):
"""Returns the coordinates of the point pin (a 3 tuple) after rotation.
Parameters
==========
pin : tuple
A 3-element tuple of coordinates of a point which needs to be
rotated.
r : Quaternion or tuple
Axis and angle of rotation.
It's important to note that when r is a tuple, it must be of the form
(axis, angle)
Returns
=======
tuple
The coordinates of the point after rotation.
Examples
========
>>> from sympy import Quaternion
>>> from sympy import symbols, trigsimp, cos, sin
>>> x = symbols('x')
>>> q = Quaternion(cos(x/2), 0, 0, sin(x/2))
>>> trigsimp(Quaternion.rotate_point((1, 1, 1), q))
(sqrt(2)*cos(x + pi/4), sqrt(2)*sin(x + pi/4), 1)
>>> (axis, angle) = q.to_axis_angle()
>>> trigsimp(Quaternion.rotate_point((1, 1, 1), (axis, angle)))
(sqrt(2)*cos(x + pi/4), sqrt(2)*sin(x + pi/4), 1)
"""
if isinstance(r, tuple):
# if r is of the form (vector, angle)
q = Quaternion.from_axis_angle(r[0], r[1])
else:
# if r is a quaternion
q = r.normalize()
pout = q * Quaternion(0, pin[0], pin[1], pin[2]) * conjugate(q)
return (pout.b, pout.c, pout.d)
def to_axis_angle(self):
"""Returns the axis and angle of rotation of a quaternion.
Returns
=======
tuple
Tuple of (axis, angle)
Examples
========
>>> from sympy import Quaternion
>>> q = Quaternion(1, 1, 1, 1)
>>> (axis, angle) = q.to_axis_angle()
>>> axis
(sqrt(3)/3, sqrt(3)/3, sqrt(3)/3)
>>> angle
2*pi/3
"""
q = self
if q.a.is_negative:
q = q * -1
q = q.normalize()
angle = trigsimp(2 * acos(q.a))
# Since quaternion is normalised, q.a is less than 1.
s = sqrt(1 - q.a*q.a)
x = trigsimp(q.b / s)
y = trigsimp(q.c / s)
z = trigsimp(q.d / s)
v = (x, y, z)
t = (v, angle)
return t
def to_rotation_matrix(self, v=None, homogeneous=True):
"""Returns the equivalent rotation transformation matrix of the quaternion
which represents rotation about the origin if ``v`` is not passed.
Parameters
==========
v : tuple or None
Default value: None
homogeneous : bool
When True, gives an expression that may be more efficient for
symbolic calculations but less so for direct evaluation. Both
formulas are mathematically equivalent.
Default value: True
Returns
=======
tuple
Returns the equivalent rotation transformation matrix of the quaternion
which represents rotation about the origin if v is not passed.
Examples
========
>>> from sympy import Quaternion
>>> from sympy import symbols, trigsimp, cos, sin
>>> x = symbols('x')
>>> q = Quaternion(cos(x/2), 0, 0, sin(x/2))
>>> trigsimp(q.to_rotation_matrix())
Matrix([
[cos(x), -sin(x), 0],
[sin(x), cos(x), 0],
[ 0, 0, 1]])
Generates a 4x4 transformation matrix (used for rotation about a point
other than the origin) if the point(v) is passed as an argument.
"""
q = self
s = q.norm()**-2
# diagonal elements are different according to parameter normal
if homogeneous:
m00 = s*(q.a**2 + q.b**2 - q.c**2 - q.d**2)
m11 = s*(q.a**2 - q.b**2 + q.c**2 - q.d**2)
m22 = s*(q.a**2 - q.b**2 - q.c**2 + q.d**2)
else:
m00 = 1 - 2*s*(q.c**2 + q.d**2)
m11 = 1 - 2*s*(q.b**2 + q.d**2)
m22 = 1 - 2*s*(q.b**2 + q.c**2)
m01 = 2*s*(q.b*q.c - q.d*q.a)
m02 = 2*s*(q.b*q.d + q.c*q.a)
m10 = 2*s*(q.b*q.c + q.d*q.a)
m12 = 2*s*(q.c*q.d - q.b*q.a)
m20 = 2*s*(q.b*q.d - q.c*q.a)
m21 = 2*s*(q.c*q.d + q.b*q.a)
if not v:
return Matrix([[m00, m01, m02], [m10, m11, m12], [m20, m21, m22]])
else:
(x, y, z) = v
m03 = x - x*m00 - y*m01 - z*m02
m13 = y - x*m10 - y*m11 - z*m12
m23 = z - x*m20 - y*m21 - z*m22
m30 = m31 = m32 = 0
m33 = 1
return Matrix([[m00, m01, m02, m03], [m10, m11, m12, m13],
[m20, m21, m22, m23], [m30, m31, m32, m33]])
def scalar_part(self):
r"""Returns scalar part($\mathbf{S}(q)$) of the quaternion q.
Explanation
===========
Given a quaternion $q = a + bi + cj + dk$, returns $\mathbf{S}(q) = a$.
Examples
========
>>> from sympy.algebras.quaternion import Quaternion
>>> q = Quaternion(4, 8, 13, 12)
>>> q.scalar_part()
4
"""
return self.a
def vector_part(self):
r"""
Returns $\mathbf{V}(q)$, the vector part of the quaternion $q$.
Explanation
===========
Given a quaternion $q = a + bi + cj + dk$, returns $\mathbf{V}(q) = bi + cj + dk$.
Examples
========
>>> from sympy.algebras.quaternion import Quaternion
>>> q = Quaternion(1, 1, 1, 1)
>>> q.vector_part()
0 + 1*i + 1*j + 1*k
>>> q = Quaternion(4, 8, 13, 12)
>>> q.vector_part()
0 + 8*i + 13*j + 12*k
"""
return Quaternion(0, self.b, self.c, self.d)
def axis(self):
r"""
Returns $\mathbf{Ax}(q)$, the axis of the quaternion $q$.
Explanation
===========
Given a quaternion $q = a + bi + cj + dk$, returns $\mathbf{Ax}(q)$ i.e., the versor of the vector part of that quaternion
equal to $\mathbf{U}[\mathbf{V}(q)]$.
The axis is always an imaginary unit with square equal to $-1 + 0i + 0j + 0k$.
Examples
========
>>> from sympy.algebras.quaternion import Quaternion
>>> q = Quaternion(1, 1, 1, 1)
>>> q.axis()
0 + sqrt(3)/3*i + sqrt(3)/3*j + sqrt(3)/3*k
See Also
========
vector_part
"""
axis = self.vector_part().normalize()
return Quaternion(0, axis.b, axis.c, axis.d)
def is_pure(self):
"""
Returns true if the quaternion is pure, false if the quaternion is not pure
or returns none if it is unknown.
Explanation
===========
A pure quaternion (also a vector quaternion) is a quaternion with scalar
part equal to 0.
Examples
========
>>> from sympy.algebras.quaternion import Quaternion
>>> q = Quaternion(0, 8, 13, 12)
>>> q.is_pure()
True
See Also
========
scalar_part
"""
return self.a.is_zero
def is_zero_quaternion(self):
"""
Returns true if the quaternion is a zero quaternion or false if it is not a zero quaternion
and None if the value is unknown.
Explanation
===========
A zero quaternion is a quaternion with both scalar part and
vector part equal to 0.
Examples
========
>>> from sympy.algebras.quaternion import Quaternion
>>> q = Quaternion(1, 0, 0, 0)
>>> q.is_zero_quaternion()
False
>>> q = Quaternion(0, 0, 0, 0)
>>> q.is_zero_quaternion()
True
See Also
========
scalar_part
vector_part
"""
return self.norm().is_zero
def angle(self):
r"""
Returns the angle of the quaternion measured in the real-axis plane.
Explanation
===========
Given a quaternion $q = a + bi + cj + dk$ where $a$, $b$, $c$ and $d$
are real numbers, returns the angle of the quaternion given by
.. math::
\theta := 2 \operatorname{atan_2}\left(\sqrt{b^2 + c^2 + d^2}, {a}\right)
Examples
========
>>> from sympy.algebras.quaternion import Quaternion
>>> q = Quaternion(1, 4, 4, 4)
>>> q.angle()
2*atan(4*sqrt(3))
"""
return 2 * atan2(self.vector_part().norm(), self.scalar_part())
def arc_coplanar(self, other):
"""
Returns True if the transformation arcs represented by the input quaternions happen in the same plane.
Explanation
===========
Two quaternions are said to be coplanar (in this arc sense) when their axes are parallel.
The plane of a quaternion is the one normal to its axis.
Parameters
==========
other : a Quaternion
Returns
=======
True : if the planes of the two quaternions are the same, apart from its orientation/sign.
False : if the planes of the two quaternions are not the same, apart from its orientation/sign.
None : if plane of either of the quaternion is unknown.
Examples
========
>>> from sympy.algebras.quaternion import Quaternion
>>> q1 = Quaternion(1, 4, 4, 4)
>>> q2 = Quaternion(3, 8, 8, 8)
>>> Quaternion.arc_coplanar(q1, q2)
True
>>> q1 = Quaternion(2, 8, 13, 12)
>>> Quaternion.arc_coplanar(q1, q2)
False
See Also
========
vector_coplanar
is_pure
"""
if (self.is_zero_quaternion()) or (other.is_zero_quaternion()):
raise ValueError('Neither of the given quaternions can be 0')
return fuzzy_or([(self.axis() - other.axis()).is_zero_quaternion(), (self.axis() + other.axis()).is_zero_quaternion()])
@classmethod
def vector_coplanar(cls, q1, q2, q3):
r"""
Returns True if the axis of the pure quaternions seen as 3D vectors
``q1``, ``q2``, and ``q3`` are coplanar.
Explanation
===========
Three pure quaternions are vector coplanar if the quaternions seen as 3D vectors are coplanar.
Parameters
==========
q1
A pure Quaternion.
q2
A pure Quaternion.
q3
A pure Quaternion.
Returns
=======
True : if the axis of the pure quaternions seen as 3D vectors
q1, q2, and q3 are coplanar.
False : if the axis of the pure quaternions seen as 3D vectors
q1, q2, and q3 are not coplanar.
None : if the axis of the pure quaternions seen as 3D vectors
q1, q2, and q3 are coplanar is unknown.
Examples
========
>>> from sympy.algebras.quaternion import Quaternion
>>> q1 = Quaternion(0, 4, 4, 4)
>>> q2 = Quaternion(0, 8, 8, 8)
>>> q3 = Quaternion(0, 24, 24, 24)
>>> Quaternion.vector_coplanar(q1, q2, q3)
True
>>> q1 = Quaternion(0, 8, 16, 8)
>>> q2 = Quaternion(0, 8, 3, 12)
>>> Quaternion.vector_coplanar(q1, q2, q3)
False
See Also
========
axis
is_pure
"""
if fuzzy_not(q1.is_pure()) or fuzzy_not(q2.is_pure()) or fuzzy_not(q3.is_pure()):
raise ValueError('The given quaternions must be pure')
M = Matrix([[q1.b, q1.c, q1.d], [q2.b, q2.c, q2.d], [q3.b, q3.c, q3.d]]).det()
return M.is_zero
def parallel(self, other):
"""
Returns True if the two pure quaternions seen as 3D vectors are parallel.
Explanation
===========
Two pure quaternions are called parallel when their vector product is commutative which
implies that the quaternions seen as 3D vectors have same direction.
Parameters
==========
other : a Quaternion
Returns
=======
True : if the two pure quaternions seen as 3D vectors are parallel.
False : if the two pure quaternions seen as 3D vectors are not parallel.
None : if the two pure quaternions seen as 3D vectors are parallel is unknown.
Examples
========
>>> from sympy.algebras.quaternion import Quaternion
>>> q = Quaternion(0, 4, 4, 4)
>>> q1 = Quaternion(0, 8, 8, 8)
>>> q.parallel(q1)
True
>>> q1 = Quaternion(0, 8, 13, 12)
>>> q.parallel(q1)
False
"""
if fuzzy_not(self.is_pure()) or fuzzy_not(other.is_pure()):
raise ValueError('The provided quaternions must be pure')
return (self*other - other*self).is_zero_quaternion()
def orthogonal(self, other):
"""
Returns the orthogonality of two quaternions.
Explanation
===========
Two pure quaternions are called orthogonal when their product is anti-commutative.
Parameters
==========
other : a Quaternion
Returns
=======
True : if the two pure quaternions seen as 3D vectors are orthogonal.
False : if the two pure quaternions seen as 3D vectors are not orthogonal.
None : if the two pure quaternions seen as 3D vectors are orthogonal is unknown.
Examples
========
>>> from sympy.algebras.quaternion import Quaternion
>>> q = Quaternion(0, 4, 4, 4)
>>> q1 = Quaternion(0, 8, 8, 8)
>>> q.orthogonal(q1)
False
>>> q1 = Quaternion(0, 2, 2, 0)
>>> q = Quaternion(0, 2, -2, 0)
>>> q.orthogonal(q1)
True
"""
if fuzzy_not(self.is_pure()) or fuzzy_not(other.is_pure()):
raise ValueError('The given quaternions must be pure')
return (self*other + other*self).is_zero_quaternion()
def index_vector(self):
r"""
Returns the index vector of the quaternion.
Explanation
===========
The index vector is given by $\mathbf{T}(q)$, the norm (or magnitude) of
the quaternion $q$, multiplied by $\mathbf{Ax}(q)$, the axis of $q$.
Returns
=======
Quaternion: representing index vector of the provided quaternion.
Examples
========
>>> from sympy.algebras.quaternion import Quaternion
>>> q = Quaternion(2, 4, 2, 4)
>>> q.index_vector()
0 + 4*sqrt(10)/3*i + 2*sqrt(10)/3*j + 4*sqrt(10)/3*k
See Also
========
axis
norm
"""
return self.norm() * self.axis()
def mensor(self):
"""
Returns the natural logarithm of the norm(magnitude) of the quaternion.
Examples
========
>>> from sympy.algebras.quaternion import Quaternion
>>> q = Quaternion(2, 4, 2, 4)
>>> q.mensor()
log(2*sqrt(10))
>>> q.norm()
2*sqrt(10)
See Also
========
norm
"""
return ln(self.norm())
PK ]ZZZg��& & sympy/assumptions/__init__.py"""
A module to implement logical predicates and assumption system.
"""
from .assume import (
AppliedPredicate, Predicate, AssumptionsContext, assuming,
global_assumptions
)
from .ask import Q, ask, register_handler, remove_handler
from .refine import refine
from .relation import BinaryRelation, AppliedBinaryRelation
__all__ = [
'AppliedPredicate', 'Predicate', 'AssumptionsContext', 'assuming',
'global_assumptions', 'Q', 'ask', 'register_handler', 'remove_handler',
'refine',
'BinaryRelation', 'AppliedBinaryRelation'
]
PK ]ZZZ�Si��K �K sympy/assumptions/ask.py"""Module for querying SymPy objects about assumptions."""
from sympy.assumptions.assume import (global_assumptions, Predicate,
AppliedPredicate)
from sympy.assumptions.cnf import CNF, EncodedCNF, Literal
from sympy.core import sympify
from sympy.core.kind import BooleanKind
from sympy.core.relational import Eq, Ne, Gt, Lt, Ge, Le
from sympy.logic.inference import satisfiable
from sympy.utilities.decorator import memoize_property
from sympy.utilities.exceptions import (sympy_deprecation_warning,
SymPyDeprecationWarning,
ignore_warnings)
# Memoization is necessary for the properties of AssumptionKeys to
# ensure that only one object of Predicate objects are created.
# This is because assumption handlers are registered on those objects.
class AssumptionKeys:
"""
This class contains all the supported keys by ``ask``.
It should be accessed via the instance ``sympy.Q``.
"""
# DO NOT add methods or properties other than predicate keys.
# SAT solver checks the properties of Q and use them to compute the
# fact system. Non-predicate attributes will break this.
@memoize_property
def hermitian(self):
from .handlers.sets import HermitianPredicate
return HermitianPredicate()
@memoize_property
def antihermitian(self):
from .handlers.sets import AntihermitianPredicate
return AntihermitianPredicate()
@memoize_property
def real(self):
from .handlers.sets import RealPredicate
return RealPredicate()
@memoize_property
def extended_real(self):
from .handlers.sets import ExtendedRealPredicate
return ExtendedRealPredicate()
@memoize_property
def imaginary(self):
from .handlers.sets import ImaginaryPredicate
return ImaginaryPredicate()
@memoize_property
def complex(self):
from .handlers.sets import ComplexPredicate
return ComplexPredicate()
@memoize_property
def algebraic(self):
from .handlers.sets import AlgebraicPredicate
return AlgebraicPredicate()
@memoize_property
def transcendental(self):
from .predicates.sets import TranscendentalPredicate
return TranscendentalPredicate()
@memoize_property
def integer(self):
from .handlers.sets import IntegerPredicate
return IntegerPredicate()
@memoize_property
def noninteger(self):
from .predicates.sets import NonIntegerPredicate
return NonIntegerPredicate()
@memoize_property
def rational(self):
from .handlers.sets import RationalPredicate
return RationalPredicate()
@memoize_property
def irrational(self):
from .handlers.sets import IrrationalPredicate
return IrrationalPredicate()
@memoize_property
def finite(self):
from .handlers.calculus import FinitePredicate
return FinitePredicate()
@memoize_property
def infinite(self):
from .handlers.calculus import InfinitePredicate
return InfinitePredicate()
@memoize_property
def positive_infinite(self):
from .handlers.calculus import PositiveInfinitePredicate
return PositiveInfinitePredicate()
@memoize_property
def negative_infinite(self):
from .handlers.calculus import NegativeInfinitePredicate
return NegativeInfinitePredicate()
@memoize_property
def positive(self):
from .handlers.order import PositivePredicate
return PositivePredicate()
@memoize_property
def negative(self):
from .handlers.order import NegativePredicate
return NegativePredicate()
@memoize_property
def zero(self):
from .handlers.order import ZeroPredicate
return ZeroPredicate()
@memoize_property
def extended_positive(self):
from .handlers.order import ExtendedPositivePredicate
return ExtendedPositivePredicate()
@memoize_property
def extended_negative(self):
from .handlers.order import ExtendedNegativePredicate
return ExtendedNegativePredicate()
@memoize_property
def nonzero(self):
from .handlers.order import NonZeroPredicate
return NonZeroPredicate()
@memoize_property
def nonpositive(self):
from .handlers.order import NonPositivePredicate
return NonPositivePredicate()
@memoize_property
def nonnegative(self):
from .handlers.order import NonNegativePredicate
return NonNegativePredicate()
@memoize_property
def extended_nonzero(self):
from .handlers.order import ExtendedNonZeroPredicate
return ExtendedNonZeroPredicate()
@memoize_property
def extended_nonpositive(self):
from .handlers.order import ExtendedNonPositivePredicate
return ExtendedNonPositivePredicate()
@memoize_property
def extended_nonnegative(self):
from .handlers.order import ExtendedNonNegativePredicate
return ExtendedNonNegativePredicate()
@memoize_property
def even(self):
from .handlers.ntheory import EvenPredicate
return EvenPredicate()
@memoize_property
def odd(self):
from .handlers.ntheory import OddPredicate
return OddPredicate()
@memoize_property
def prime(self):
from .handlers.ntheory import PrimePredicate
return PrimePredicate()
@memoize_property
def composite(self):
from .handlers.ntheory import CompositePredicate
return CompositePredicate()
@memoize_property
def commutative(self):
from .handlers.common import CommutativePredicate
return CommutativePredicate()
@memoize_property
def is_true(self):
from .handlers.common import IsTruePredicate
return IsTruePredicate()
@memoize_property
def symmetric(self):
from .handlers.matrices import SymmetricPredicate
return SymmetricPredicate()
@memoize_property
def invertible(self):
from .handlers.matrices import InvertiblePredicate
return InvertiblePredicate()
@memoize_property
def orthogonal(self):
from .handlers.matrices import OrthogonalPredicate
return OrthogonalPredicate()
@memoize_property
def unitary(self):
from .handlers.matrices import UnitaryPredicate
return UnitaryPredicate()
@memoize_property
def positive_definite(self):
from .handlers.matrices import PositiveDefinitePredicate
return PositiveDefinitePredicate()
@memoize_property
def upper_triangular(self):
from .handlers.matrices import UpperTriangularPredicate
return UpperTriangularPredicate()
@memoize_property
def lower_triangular(self):
from .handlers.matrices import LowerTriangularPredicate
return LowerTriangularPredicate()
@memoize_property
def diagonal(self):
from .handlers.matrices import DiagonalPredicate
return DiagonalPredicate()
@memoize_property
def fullrank(self):
from .handlers.matrices import FullRankPredicate
return FullRankPredicate()
@memoize_property
def square(self):
from .handlers.matrices import SquarePredicate
return SquarePredicate()
@memoize_property
def integer_elements(self):
from .handlers.matrices import IntegerElementsPredicate
return IntegerElementsPredicate()
@memoize_property
def real_elements(self):
from .handlers.matrices import RealElementsPredicate
return RealElementsPredicate()
@memoize_property
def complex_elements(self):
from .handlers.matrices import ComplexElementsPredicate
return ComplexElementsPredicate()
@memoize_property
def singular(self):
from .predicates.matrices import SingularPredicate
return SingularPredicate()
@memoize_property
def normal(self):
from .predicates.matrices import NormalPredicate
return NormalPredicate()
@memoize_property
def triangular(self):
from .predicates.matrices import TriangularPredicate
return TriangularPredicate()
@memoize_property
def unit_triangular(self):
from .predicates.matrices import UnitTriangularPredicate
return UnitTriangularPredicate()
@memoize_property
def eq(self):
from .relation.equality import EqualityPredicate
return EqualityPredicate()
@memoize_property
def ne(self):
from .relation.equality import UnequalityPredicate
return UnequalityPredicate()
@memoize_property
def gt(self):
from .relation.equality import StrictGreaterThanPredicate
return StrictGreaterThanPredicate()
@memoize_property
def ge(self):
from .relation.equality import GreaterThanPredicate
return GreaterThanPredicate()
@memoize_property
def lt(self):
from .relation.equality import StrictLessThanPredicate
return StrictLessThanPredicate()
@memoize_property
def le(self):
from .relation.equality import LessThanPredicate
return LessThanPredicate()
Q = AssumptionKeys()
def _extract_all_facts(assump, exprs):
"""
Extract all relevant assumptions from *assump* with respect to given *exprs*.
Parameters
==========
assump : sympy.assumptions.cnf.CNF
exprs : tuple of expressions
Returns
=======
sympy.assumptions.cnf.CNF
Examples
========
>>> from sympy import Q
>>> from sympy.assumptions.cnf import CNF
>>> from sympy.assumptions.ask import _extract_all_facts
>>> from sympy.abc import x, y
>>> assump = CNF.from_prop(Q.positive(x) & Q.integer(y))
>>> exprs = (x,)
>>> cnf = _extract_all_facts(assump, exprs)
>>> cnf.clauses
{frozenset({Literal(Q.positive, False)})}
"""
facts = set()
for clause in assump.clauses:
args = []
for literal in clause:
if isinstance(literal.lit, AppliedPredicate) and len(literal.lit.arguments) == 1:
if literal.lit.arg in exprs:
# Add literal if it has matching in it
args.append(Literal(literal.lit.function, literal.is_Not))
else:
# If any of the literals doesn't have matching expr don't add the whole clause.
break
else:
# If any of the literals aren't unary predicate don't add the whole clause.
break
else:
if args:
facts.add(frozenset(args))
return CNF(facts)
def ask(proposition, assumptions=True, context=global_assumptions):
"""
Function to evaluate the proposition with assumptions.
Explanation
===========
This function evaluates the proposition to ``True`` or ``False`` if
the truth value can be determined. If not, it returns ``None``.
It should be discerned from :func:`~.refine` which, when applied to a
proposition, simplifies the argument to symbolic ``Boolean`` instead of
Python built-in ``True``, ``False`` or ``None``.
**Syntax**
* ask(proposition)
Evaluate the *proposition* in global assumption context.
* ask(proposition, assumptions)
Evaluate the *proposition* with respect to *assumptions* in
global assumption context.
Parameters
==========
proposition : Boolean
Proposition which will be evaluated to boolean value. If this is
not ``AppliedPredicate``, it will be wrapped by ``Q.is_true``.
assumptions : Boolean, optional
Local assumptions to evaluate the *proposition*.
context : AssumptionsContext, optional
Default assumptions to evaluate the *proposition*. By default,
this is ``sympy.assumptions.global_assumptions`` variable.
Returns
=======
``True``, ``False``, or ``None``
Raises
======
TypeError : *proposition* or *assumptions* is not valid logical expression.
ValueError : assumptions are inconsistent.
Examples
========
>>> from sympy import ask, Q, pi
>>> from sympy.abc import x, y
>>> ask(Q.rational(pi))
False
>>> ask(Q.even(x*y), Q.even(x) & Q.integer(y))
True
>>> ask(Q.prime(4*x), Q.integer(x))
False
If the truth value cannot be determined, ``None`` will be returned.
>>> print(ask(Q.odd(3*x))) # cannot determine unless we know x
None
``ValueError`` is raised if assumptions are inconsistent.
>>> ask(Q.integer(x), Q.even(x) & Q.odd(x))
Traceback (most recent call last):
...
ValueError: inconsistent assumptions Q.even(x) & Q.odd(x)
Notes
=====
Relations in assumptions are not implemented (yet), so the following
will not give a meaningful result.
>>> ask(Q.positive(x), x > 0)
It is however a work in progress.
See Also
========
sympy.assumptions.refine.refine : Simplification using assumptions.
Proposition is not reduced to ``None`` if the truth value cannot
be determined.
"""
from sympy.assumptions.satask import satask
from sympy.assumptions.lra_satask import lra_satask
from sympy.logic.algorithms.lra_theory import UnhandledInput
proposition = sympify(proposition)
assumptions = sympify(assumptions)
if isinstance(proposition, Predicate) or proposition.kind is not BooleanKind:
raise TypeError("proposition must be a valid logical expression")
if isinstance(assumptions, Predicate) or assumptions.kind is not BooleanKind:
raise TypeError("assumptions must be a valid logical expression")
binrelpreds = {Eq: Q.eq, Ne: Q.ne, Gt: Q.gt, Lt: Q.lt, Ge: Q.ge, Le: Q.le}
if isinstance(proposition, AppliedPredicate):
key, args = proposition.function, proposition.arguments
elif proposition.func in binrelpreds:
key, args = binrelpreds[type(proposition)], proposition.args
else:
key, args = Q.is_true, (proposition,)
# convert local and global assumptions to CNF
assump_cnf = CNF.from_prop(assumptions)
assump_cnf.extend(context)
# extract the relevant facts from assumptions with respect to args
local_facts = _extract_all_facts(assump_cnf, args)
# convert default facts and assumed facts to encoded CNF
known_facts_cnf = get_all_known_facts()
enc_cnf = EncodedCNF()
enc_cnf.from_cnf(CNF(known_facts_cnf))
enc_cnf.add_from_cnf(local_facts)
# check the satisfiability of given assumptions
if local_facts.clauses and satisfiable(enc_cnf) is False:
raise ValueError("inconsistent assumptions %s" % assumptions)
# quick computation for single fact
res = _ask_single_fact(key, local_facts)
if res is not None:
return res
# direct resolution method, no logic
res = key(*args)._eval_ask(assumptions)
if res is not None:
return bool(res)
# using satask (still costly)
res = satask(proposition, assumptions=assumptions, context=context)
if res is not None:
return res
try:
res = lra_satask(proposition, assumptions=assumptions, context=context)
except UnhandledInput:
return None
return res
def _ask_single_fact(key, local_facts):
"""
Compute the truth value of single predicate using assumptions.
Parameters
==========
key : sympy.assumptions.assume.Predicate
Proposition predicate.
local_facts : sympy.assumptions.cnf.CNF
Local assumption in CNF form.
Returns
=======
``True``, ``False`` or ``None``
Examples
========
>>> from sympy import Q
>>> from sympy.assumptions.cnf import CNF
>>> from sympy.assumptions.ask import _ask_single_fact
If prerequisite of proposition is rejected by the assumption,
return ``False``.
>>> key, assump = Q.zero, ~Q.zero
>>> local_facts = CNF.from_prop(assump)
>>> _ask_single_fact(key, local_facts)
False
>>> key, assump = Q.zero, ~Q.even
>>> local_facts = CNF.from_prop(assump)
>>> _ask_single_fact(key, local_facts)
False
If assumption implies the proposition, return ``True``.
>>> key, assump = Q.even, Q.zero
>>> local_facts = CNF.from_prop(assump)
>>> _ask_single_fact(key, local_facts)
True
If proposition rejects the assumption, return ``False``.
>>> key, assump = Q.even, Q.odd
>>> local_facts = CNF.from_prop(assump)
>>> _ask_single_fact(key, local_facts)
False
"""
if local_facts.clauses:
known_facts_dict = get_known_facts_dict()
if len(local_facts.clauses) == 1:
cl, = local_facts.clauses
if len(cl) == 1:
f, = cl
prop_facts = known_facts_dict.get(key, None)
prop_req = prop_facts[0] if prop_facts is not None else set()
if f.is_Not and f.arg in prop_req:
# the prerequisite of proposition is rejected
return False
for clause in local_facts.clauses:
if len(clause) == 1:
f, = clause
prop_facts = known_facts_dict.get(f.arg, None) if not f.is_Not else None
if prop_facts is None:
continue
prop_req, prop_rej = prop_facts
if key in prop_req:
# assumption implies the proposition
return True
elif key in prop_rej:
# proposition rejects the assumption
return False
return None
def register_handler(key, handler):
"""
Register a handler in the ask system. key must be a string and handler a
class inheriting from AskHandler.
.. deprecated:: 1.8.
Use multipledispatch handler instead. See :obj:`~.Predicate`.
"""
sympy_deprecation_warning(
"""
The AskHandler system is deprecated. The register_handler() function
should be replaced with the multipledispatch handler of Predicate.
""",
deprecated_since_version="1.8",
active_deprecations_target='deprecated-askhandler',
)
if isinstance(key, Predicate):
key = key.name.name
Qkey = getattr(Q, key, None)
if Qkey is not None:
Qkey.add_handler(handler)
else:
setattr(Q, key, Predicate(key, handlers=[handler]))
def remove_handler(key, handler):
"""
Removes a handler from the ask system.
.. deprecated:: 1.8.
Use multipledispatch handler instead. See :obj:`~.Predicate`.
"""
sympy_deprecation_warning(
"""
The AskHandler system is deprecated. The remove_handler() function
should be replaced with the multipledispatch handler of Predicate.
""",
deprecated_since_version="1.8",
active_deprecations_target='deprecated-askhandler',
)
if isinstance(key, Predicate):
key = key.name.name
# Don't show the same warning again recursively
with ignore_warnings(SymPyDeprecationWarning):
getattr(Q, key).remove_handler(handler)
from sympy.assumptions.ask_generated import (get_all_known_facts,
get_known_facts_dict)
PK ]ZZZ�)��\ \ " sympy/assumptions/ask_generated.py"""
Do NOT manually edit this file.
Instead, run ./bin/ask_update.py.
"""
from sympy.assumptions.ask import Q
from sympy.assumptions.cnf import Literal
from sympy.core.cache import cacheit
@cacheit
def get_all_known_facts():
"""
Known facts between unary predicates as CNF clauses.
"""
return {
frozenset((Literal(Q.algebraic, False), Literal(Q.imaginary, True), Literal(Q.transcendental, False))),
frozenset((Literal(Q.algebraic, False), Literal(Q.negative, True), Literal(Q.transcendental, False))),
frozenset((Literal(Q.algebraic, False), Literal(Q.positive, True), Literal(Q.transcendental, False))),
frozenset((Literal(Q.algebraic, False), Literal(Q.rational, True))),
frozenset((Literal(Q.algebraic, False), Literal(Q.transcendental, False), Literal(Q.zero, True))),
frozenset((Literal(Q.algebraic, True), Literal(Q.finite, False))),
frozenset((Literal(Q.algebraic, True), Literal(Q.transcendental, True))),
frozenset((Literal(Q.antihermitian, False), Literal(Q.hermitian, False), Literal(Q.zero, True))),
frozenset((Literal(Q.antihermitian, False), Literal(Q.imaginary, True))),
frozenset((Literal(Q.commutative, False), Literal(Q.finite, True))),
frozenset((Literal(Q.commutative, False), Literal(Q.infinite, True))),
frozenset((Literal(Q.complex_elements, False), Literal(Q.real_elements, True))),
frozenset((Literal(Q.composite, False), Literal(Q.even, True), Literal(Q.positive, True), Literal(Q.prime, False))),
frozenset((Literal(Q.composite, True), Literal(Q.even, False), Literal(Q.odd, False))),
frozenset((Literal(Q.composite, True), Literal(Q.positive, False))),
frozenset((Literal(Q.composite, True), Literal(Q.prime, True))),
frozenset((Literal(Q.diagonal, False), Literal(Q.lower_triangular, True), Literal(Q.upper_triangular, True))),
frozenset((Literal(Q.diagonal, True), Literal(Q.lower_triangular, False))),
frozenset((Literal(Q.diagonal, True), Literal(Q.normal, False))),
frozenset((Literal(Q.diagonal, True), Literal(Q.symmetric, False))),
frozenset((Literal(Q.diagonal, True), Literal(Q.upper_triangular, False))),
frozenset((Literal(Q.even, False), Literal(Q.odd, False), Literal(Q.prime, True))),
frozenset((Literal(Q.even, False), Literal(Q.zero, True))),
frozenset((Literal(Q.even, True), Literal(Q.odd, True))),
frozenset((Literal(Q.even, True), Literal(Q.rational, False))),
frozenset((Literal(Q.finite, False), Literal(Q.transcendental, True))),
frozenset((Literal(Q.finite, True), Literal(Q.infinite, True))),
frozenset((Literal(Q.fullrank, False), Literal(Q.invertible, True))),
frozenset((Literal(Q.fullrank, True), Literal(Q.invertible, False), Literal(Q.square, True))),
frozenset((Literal(Q.hermitian, False), Literal(Q.negative, True))),
frozenset((Literal(Q.hermitian, False), Literal(Q.positive, True))),
frozenset((Literal(Q.hermitian, False), Literal(Q.zero, True))),
frozenset((Literal(Q.imaginary, True), Literal(Q.negative, True))),
frozenset((Literal(Q.imaginary, True), Literal(Q.positive, True))),
frozenset((Literal(Q.imaginary, True), Literal(Q.zero, True))),
frozenset((Literal(Q.infinite, False), Literal(Q.negative_infinite, True))),
frozenset((Literal(Q.infinite, False), Literal(Q.positive_infinite, True))),
frozenset((Literal(Q.integer_elements, True), Literal(Q.real_elements, False))),
frozenset((Literal(Q.invertible, False), Literal(Q.positive_definite, True))),
frozenset((Literal(Q.invertible, False), Literal(Q.singular, False))),
frozenset((Literal(Q.invertible, False), Literal(Q.unitary, True))),
frozenset((Literal(Q.invertible, True), Literal(Q.singular, True))),
frozenset((Literal(Q.invertible, True), Literal(Q.square, False))),
frozenset((Literal(Q.irrational, False), Literal(Q.negative, True), Literal(Q.rational, False))),
frozenset((Literal(Q.irrational, False), Literal(Q.positive, True), Literal(Q.rational, False))),
frozenset((Literal(Q.irrational, False), Literal(Q.rational, False), Literal(Q.zero, True))),
frozenset((Literal(Q.irrational, True), Literal(Q.negative, False), Literal(Q.positive, False), Literal(Q.zero, False))),
frozenset((Literal(Q.irrational, True), Literal(Q.rational, True))),
frozenset((Literal(Q.lower_triangular, False), Literal(Q.triangular, True), Literal(Q.upper_triangular, False))),
frozenset((Literal(Q.lower_triangular, True), Literal(Q.triangular, False))),
frozenset((Literal(Q.negative, False), Literal(Q.positive, False), Literal(Q.rational, True), Literal(Q.zero, False))),
frozenset((Literal(Q.negative, True), Literal(Q.negative_infinite, True))),
frozenset((Literal(Q.negative, True), Literal(Q.positive, True))),
frozenset((Literal(Q.negative, True), Literal(Q.positive_infinite, True))),
frozenset((Literal(Q.negative, True), Literal(Q.zero, True))),
frozenset((Literal(Q.negative_infinite, True), Literal(Q.positive, True))),
frozenset((Literal(Q.negative_infinite, True), Literal(Q.positive_infinite, True))),
frozenset((Literal(Q.negative_infinite, True), Literal(Q.zero, True))),
frozenset((Literal(Q.normal, False), Literal(Q.unitary, True))),
frozenset((Literal(Q.normal, True), Literal(Q.square, False))),
frozenset((Literal(Q.odd, True), Literal(Q.rational, False))),
frozenset((Literal(Q.orthogonal, False), Literal(Q.real_elements, True), Literal(Q.unitary, True))),
frozenset((Literal(Q.orthogonal, True), Literal(Q.positive_definite, False))),
frozenset((Literal(Q.orthogonal, True), Literal(Q.unitary, False))),
frozenset((Literal(Q.positive, False), Literal(Q.prime, True))),
frozenset((Literal(Q.positive, True), Literal(Q.positive_infinite, True))),
frozenset((Literal(Q.positive, True), Literal(Q.zero, True))),
frozenset((Literal(Q.positive_infinite, True), Literal(Q.zero, True))),
frozenset((Literal(Q.square, False), Literal(Q.symmetric, True))),
frozenset((Literal(Q.triangular, False), Literal(Q.unit_triangular, True))),
frozenset((Literal(Q.triangular, False), Literal(Q.upper_triangular, True)))
}
@cacheit
def get_all_known_matrix_facts():
"""
Known facts between unary predicates for matrices as CNF clauses.
"""
return {
frozenset((Literal(Q.complex_elements, False), Literal(Q.real_elements, True))),
frozenset((Literal(Q.diagonal, False), Literal(Q.lower_triangular, True), Literal(Q.upper_triangular, True))),
frozenset((Literal(Q.diagonal, True), Literal(Q.lower_triangular, False))),
frozenset((Literal(Q.diagonal, True), Literal(Q.normal, False))),
frozenset((Literal(Q.diagonal, True), Literal(Q.symmetric, False))),
frozenset((Literal(Q.diagonal, True), Literal(Q.upper_triangular, False))),
frozenset((Literal(Q.fullrank, False), Literal(Q.invertible, True))),
frozenset((Literal(Q.fullrank, True), Literal(Q.invertible, False), Literal(Q.square, True))),
frozenset((Literal(Q.integer_elements, True), Literal(Q.real_elements, False))),
frozenset((Literal(Q.invertible, False), Literal(Q.positive_definite, True))),
frozenset((Literal(Q.invertible, False), Literal(Q.singular, False))),
frozenset((Literal(Q.invertible, False), Literal(Q.unitary, True))),
frozenset((Literal(Q.invertible, True), Literal(Q.singular, True))),
frozenset((Literal(Q.invertible, True), Literal(Q.square, False))),
frozenset((Literal(Q.lower_triangular, False), Literal(Q.triangular, True), Literal(Q.upper_triangular, False))),
frozenset((Literal(Q.lower_triangular, True), Literal(Q.triangular, False))),
frozenset((Literal(Q.normal, False), Literal(Q.unitary, True))),
frozenset((Literal(Q.normal, True), Literal(Q.square, False))),
frozenset((Literal(Q.orthogonal, False), Literal(Q.real_elements, True), Literal(Q.unitary, True))),
frozenset((Literal(Q.orthogonal, True), Literal(Q.positive_definite, False))),
frozenset((Literal(Q.orthogonal, True), Literal(Q.unitary, False))),
frozenset((Literal(Q.square, False), Literal(Q.symmetric, True))),
frozenset((Literal(Q.triangular, False), Literal(Q.unit_triangular, True))),
frozenset((Literal(Q.triangular, False), Literal(Q.upper_triangular, True)))
}
@cacheit
def get_all_known_number_facts():
"""
Known facts between unary predicates for numbers as CNF clauses.
"""
return {
frozenset((Literal(Q.algebraic, False), Literal(Q.imaginary, True), Literal(Q.transcendental, False))),
frozenset((Literal(Q.algebraic, False), Literal(Q.negative, True), Literal(Q.transcendental, False))),
frozenset((Literal(Q.algebraic, False), Literal(Q.positive, True), Literal(Q.transcendental, False))),
frozenset((Literal(Q.algebraic, False), Literal(Q.rational, True))),
frozenset((Literal(Q.algebraic, False), Literal(Q.transcendental, False), Literal(Q.zero, True))),
frozenset((Literal(Q.algebraic, True), Literal(Q.finite, False))),
frozenset((Literal(Q.algebraic, True), Literal(Q.transcendental, True))),
frozenset((Literal(Q.antihermitian, False), Literal(Q.hermitian, False), Literal(Q.zero, True))),
frozenset((Literal(Q.antihermitian, False), Literal(Q.imaginary, True))),
frozenset((Literal(Q.commutative, False), Literal(Q.finite, True))),
frozenset((Literal(Q.commutative, False), Literal(Q.infinite, True))),
frozenset((Literal(Q.composite, False), Literal(Q.even, True), Literal(Q.positive, True), Literal(Q.prime, False))),
frozenset((Literal(Q.composite, True), Literal(Q.even, False), Literal(Q.odd, False))),
frozenset((Literal(Q.composite, True), Literal(Q.positive, False))),
frozenset((Literal(Q.composite, True), Literal(Q.prime, True))),
frozenset((Literal(Q.even, False), Literal(Q.odd, False), Literal(Q.prime, True))),
frozenset((Literal(Q.even, False), Literal(Q.zero, True))),
frozenset((Literal(Q.even, True), Literal(Q.odd, True))),
frozenset((Literal(Q.even, True), Literal(Q.rational, False))),
frozenset((Literal(Q.finite, False), Literal(Q.transcendental, True))),
frozenset((Literal(Q.finite, True), Literal(Q.infinite, True))),
frozenset((Literal(Q.hermitian, False), Literal(Q.negative, True))),
frozenset((Literal(Q.hermitian, False), Literal(Q.positive, True))),
frozenset((Literal(Q.hermitian, False), Literal(Q.zero, True))),
frozenset((Literal(Q.imaginary, True), Literal(Q.negative, True))),
frozenset((Literal(Q.imaginary, True), Literal(Q.positive, True))),
frozenset((Literal(Q.imaginary, True), Literal(Q.zero, True))),
frozenset((Literal(Q.infinite, False), Literal(Q.negative_infinite, True))),
frozenset((Literal(Q.infinite, False), Literal(Q.positive_infinite, True))),
frozenset((Literal(Q.irrational, False), Literal(Q.negative, True), Literal(Q.rational, False))),
frozenset((Literal(Q.irrational, False), Literal(Q.positive, True), Literal(Q.rational, False))),
frozenset((Literal(Q.irrational, False), Literal(Q.rational, False), Literal(Q.zero, True))),
frozenset((Literal(Q.irrational, True), Literal(Q.negative, False), Literal(Q.positive, False), Literal(Q.zero, False))),
frozenset((Literal(Q.irrational, True), Literal(Q.rational, True))),
frozenset((Literal(Q.negative, False), Literal(Q.positive, False), Literal(Q.rational, True), Literal(Q.zero, False))),
frozenset((Literal(Q.negative, True), Literal(Q.negative_infinite, True))),
frozenset((Literal(Q.negative, True), Literal(Q.positive, True))),
frozenset((Literal(Q.negative, True), Literal(Q.positive_infinite, True))),
frozenset((Literal(Q.negative, True), Literal(Q.zero, True))),
frozenset((Literal(Q.negative_infinite, True), Literal(Q.positive, True))),
frozenset((Literal(Q.negative_infinite, True), Literal(Q.positive_infinite, True))),
frozenset((Literal(Q.negative_infinite, True), Literal(Q.zero, True))),
frozenset((Literal(Q.odd, True), Literal(Q.rational, False))),
frozenset((Literal(Q.positive, False), Literal(Q.prime, True))),
frozenset((Literal(Q.positive, True), Literal(Q.positive_infinite, True))),
frozenset((Literal(Q.positive, True), Literal(Q.zero, True))),
frozenset((Literal(Q.positive_infinite, True), Literal(Q.zero, True)))
}
@cacheit
def get_known_facts_dict():
"""
Logical relations between unary predicates as dictionary.
Each key is a predicate, and item is two groups of predicates.
First group contains the predicates which are implied by the key, and
second group contains the predicates which are rejected by the key.
"""
return {
Q.algebraic: (set([Q.algebraic, Q.commutative, Q.complex, Q.finite]),
set([Q.infinite, Q.negative_infinite, Q.positive_infinite,
Q.transcendental])),
Q.antihermitian: (set([Q.antihermitian]), set([])),
Q.commutative: (set([Q.commutative]), set([])),
Q.complex: (set([Q.commutative, Q.complex, Q.finite]),
set([Q.infinite, Q.negative_infinite, Q.positive_infinite])),
Q.complex_elements: (set([Q.complex_elements]), set([])),
Q.composite: (set([Q.algebraic, Q.commutative, Q.complex, Q.composite,
Q.extended_nonnegative, Q.extended_nonzero,
Q.extended_positive, Q.extended_real, Q.finite, Q.hermitian,
Q.integer, Q.nonnegative, Q.nonzero, Q.positive, Q.rational,
Q.real]), set([Q.extended_negative, Q.extended_nonpositive,
Q.imaginary, Q.infinite, Q.irrational, Q.negative,
Q.negative_infinite, Q.nonpositive, Q.positive_infinite,
Q.prime, Q.transcendental, Q.zero])),
Q.diagonal: (set([Q.diagonal, Q.lower_triangular, Q.normal, Q.square,
Q.symmetric, Q.triangular, Q.upper_triangular]), set([])),
Q.even: (set([Q.algebraic, Q.commutative, Q.complex, Q.even,
Q.extended_real, Q.finite, Q.hermitian, Q.integer, Q.rational,
Q.real]), set([Q.imaginary, Q.infinite, Q.irrational,
Q.negative_infinite, Q.odd, Q.positive_infinite,
Q.transcendental])),
Q.extended_negative: (set([Q.commutative, Q.extended_negative,
Q.extended_nonpositive, Q.extended_nonzero, Q.extended_real]),
set([Q.composite, Q.extended_nonnegative, Q.extended_positive,
Q.imaginary, Q.nonnegative, Q.positive, Q.positive_infinite,
Q.prime, Q.zero])),
Q.extended_nonnegative: (set([Q.commutative, Q.extended_nonnegative,
Q.extended_real]), set([Q.extended_negative, Q.imaginary,
Q.negative, Q.negative_infinite])),
Q.extended_nonpositive: (set([Q.commutative, Q.extended_nonpositive,
Q.extended_real]), set([Q.composite, Q.extended_positive,
Q.imaginary, Q.positive, Q.positive_infinite, Q.prime])),
Q.extended_nonzero: (set([Q.commutative, Q.extended_nonzero,
Q.extended_real]), set([Q.imaginary, Q.zero])),
Q.extended_positive: (set([Q.commutative, Q.extended_nonnegative,
Q.extended_nonzero, Q.extended_positive, Q.extended_real]),
set([Q.extended_negative, Q.extended_nonpositive, Q.imaginary,
Q.negative, Q.negative_infinite, Q.nonpositive, Q.zero])),
Q.extended_real: (set([Q.commutative, Q.extended_real]),
set([Q.imaginary])),
Q.finite: (set([Q.commutative, Q.finite]), set([Q.infinite,
Q.negative_infinite, Q.positive_infinite])),
Q.fullrank: (set([Q.fullrank]), set([])),
Q.hermitian: (set([Q.hermitian]), set([])),
Q.imaginary: (set([Q.antihermitian, Q.commutative, Q.complex,
Q.finite, Q.imaginary]), set([Q.composite, Q.even,
Q.extended_negative, Q.extended_nonnegative,
Q.extended_nonpositive, Q.extended_nonzero,
Q.extended_positive, Q.extended_real, Q.infinite, Q.integer,
Q.irrational, Q.negative, Q.negative_infinite, Q.nonnegative,
Q.nonpositive, Q.nonzero, Q.odd, Q.positive,
Q.positive_infinite, Q.prime, Q.rational, Q.real, Q.zero])),
Q.infinite: (set([Q.commutative, Q.infinite]), set([Q.algebraic,
Q.complex, Q.composite, Q.even, Q.finite, Q.imaginary,
Q.integer, Q.irrational, Q.negative, Q.nonnegative,
Q.nonpositive, Q.nonzero, Q.odd, Q.positive, Q.prime,
Q.rational, Q.real, Q.transcendental, Q.zero])),
Q.integer: (set([Q.algebraic, Q.commutative, Q.complex,
Q.extended_real, Q.finite, Q.hermitian, Q.integer, Q.rational,
Q.real]), set([Q.imaginary, Q.infinite, Q.irrational,
Q.negative_infinite, Q.positive_infinite, Q.transcendental])),
Q.integer_elements: (set([Q.complex_elements, Q.integer_elements,
Q.real_elements]), set([])),
Q.invertible: (set([Q.fullrank, Q.invertible, Q.square]),
set([Q.singular])),
Q.irrational: (set([Q.commutative, Q.complex, Q.extended_nonzero,
Q.extended_real, Q.finite, Q.hermitian, Q.irrational,
Q.nonzero, Q.real]), set([Q.composite, Q.even, Q.imaginary,
Q.infinite, Q.integer, Q.negative_infinite, Q.odd,
Q.positive_infinite, Q.prime, Q.rational, Q.zero])),
Q.is_true: (set([Q.is_true]), set([])),
Q.lower_triangular: (set([Q.lower_triangular, Q.triangular]), set([])),
Q.negative: (set([Q.commutative, Q.complex, Q.extended_negative,
Q.extended_nonpositive, Q.extended_nonzero, Q.extended_real,
Q.finite, Q.hermitian, Q.negative, Q.nonpositive, Q.nonzero,
Q.real]), set([Q.composite, Q.extended_nonnegative,
Q.extended_positive, Q.imaginary, Q.infinite,
Q.negative_infinite, Q.nonnegative, Q.positive,
Q.positive_infinite, Q.prime, Q.zero])),
Q.negative_infinite: (set([Q.commutative, Q.extended_negative,
Q.extended_nonpositive, Q.extended_nonzero, Q.extended_real,
Q.infinite, Q.negative_infinite]), set([Q.algebraic,
Q.complex, Q.composite, Q.even, Q.extended_nonnegative,
Q.extended_positive, Q.finite, Q.imaginary, Q.integer,
Q.irrational, Q.negative, Q.nonnegative, Q.nonpositive,
Q.nonzero, Q.odd, Q.positive, Q.positive_infinite, Q.prime,
Q.rational, Q.real, Q.transcendental, Q.zero])),
Q.noninteger: (set([Q.noninteger]), set([])),
Q.nonnegative: (set([Q.commutative, Q.complex, Q.extended_nonnegative,
Q.extended_real, Q.finite, Q.hermitian, Q.nonnegative,
Q.real]), set([Q.extended_negative, Q.imaginary, Q.infinite,
Q.negative, Q.negative_infinite, Q.positive_infinite])),
Q.nonpositive: (set([Q.commutative, Q.complex, Q.extended_nonpositive,
Q.extended_real, Q.finite, Q.hermitian, Q.nonpositive,
Q.real]), set([Q.composite, Q.extended_positive, Q.imaginary,
Q.infinite, Q.negative_infinite, Q.positive,
Q.positive_infinite, Q.prime])),
Q.nonzero: (set([Q.commutative, Q.complex, Q.extended_nonzero,
Q.extended_real, Q.finite, Q.hermitian, Q.nonzero, Q.real]),
set([Q.imaginary, Q.infinite, Q.negative_infinite,
Q.positive_infinite, Q.zero])),
Q.normal: (set([Q.normal, Q.square]), set([])),
Q.odd: (set([Q.algebraic, Q.commutative, Q.complex,
Q.extended_nonzero, Q.extended_real, Q.finite, Q.hermitian,
Q.integer, Q.nonzero, Q.odd, Q.rational, Q.real]),
set([Q.even, Q.imaginary, Q.infinite, Q.irrational,
Q.negative_infinite, Q.positive_infinite, Q.transcendental,
Q.zero])),
Q.orthogonal: (set([Q.fullrank, Q.invertible, Q.normal, Q.orthogonal,
Q.positive_definite, Q.square, Q.unitary]), set([Q.singular])),
Q.positive: (set([Q.commutative, Q.complex, Q.extended_nonnegative,
Q.extended_nonzero, Q.extended_positive, Q.extended_real,
Q.finite, Q.hermitian, Q.nonnegative, Q.nonzero, Q.positive,
Q.real]), set([Q.extended_negative, Q.extended_nonpositive,
Q.imaginary, Q.infinite, Q.negative, Q.negative_infinite,
Q.nonpositive, Q.positive_infinite, Q.zero])),
Q.positive_definite: (set([Q.fullrank, Q.invertible,
Q.positive_definite, Q.square]), set([Q.singular])),
Q.positive_infinite: (set([Q.commutative, Q.extended_nonnegative,
Q.extended_nonzero, Q.extended_positive, Q.extended_real,
Q.infinite, Q.positive_infinite]), set([Q.algebraic,
Q.complex, Q.composite, Q.even, Q.extended_negative,
Q.extended_nonpositive, Q.finite, Q.imaginary, Q.integer,
Q.irrational, Q.negative, Q.negative_infinite, Q.nonnegative,
Q.nonpositive, Q.nonzero, Q.odd, Q.positive, Q.prime,
Q.rational, Q.real, Q.transcendental, Q.zero])),
Q.prime: (set([Q.algebraic, Q.commutative, Q.complex,
Q.extended_nonnegative, Q.extended_nonzero,
Q.extended_positive, Q.extended_real, Q.finite, Q.hermitian,
Q.integer, Q.nonnegative, Q.nonzero, Q.positive, Q.prime,
Q.rational, Q.real]), set([Q.composite, Q.extended_negative,
Q.extended_nonpositive, Q.imaginary, Q.infinite, Q.irrational,
Q.negative, Q.negative_infinite, Q.nonpositive,
Q.positive_infinite, Q.transcendental, Q.zero])),
Q.rational: (set([Q.algebraic, Q.commutative, Q.complex,
Q.extended_real, Q.finite, Q.hermitian, Q.rational, Q.real]),
set([Q.imaginary, Q.infinite, Q.irrational,
Q.negative_infinite, Q.positive_infinite, Q.transcendental])),
Q.real: (set([Q.commutative, Q.complex, Q.extended_real, Q.finite,
Q.hermitian, Q.real]), set([Q.imaginary, Q.infinite,
Q.negative_infinite, Q.positive_infinite])),
Q.real_elements: (set([Q.complex_elements, Q.real_elements]), set([])),
Q.singular: (set([Q.singular]), set([Q.invertible, Q.orthogonal,
Q.positive_definite, Q.unitary])),
Q.square: (set([Q.square]), set([])),
Q.symmetric: (set([Q.square, Q.symmetric]), set([])),
Q.transcendental: (set([Q.commutative, Q.complex, Q.finite,
Q.transcendental]), set([Q.algebraic, Q.composite, Q.even,
Q.infinite, Q.integer, Q.negative_infinite, Q.odd,
Q.positive_infinite, Q.prime, Q.rational, Q.zero])),
Q.triangular: (set([Q.triangular]), set([])),
Q.unit_triangular: (set([Q.triangular, Q.unit_triangular]), set([])),
Q.unitary: (set([Q.fullrank, Q.invertible, Q.normal, Q.square,
Q.unitary]), set([Q.singular])),
Q.upper_triangular: (set([Q.triangular, Q.upper_triangular]), set([])),
Q.zero: (set([Q.algebraic, Q.commutative, Q.complex, Q.even,
Q.extended_nonnegative, Q.extended_nonpositive,
Q.extended_real, Q.finite, Q.hermitian, Q.integer,
Q.nonnegative, Q.nonpositive, Q.rational, Q.real, Q.zero]),
set([Q.composite, Q.extended_negative, Q.extended_nonzero,
Q.extended_positive, Q.imaginary, Q.infinite, Q.irrational,
Q.negative, Q.negative_infinite, Q.nonzero, Q.odd, Q.positive,
Q.positive_infinite, Q.prime, Q.transcendental])),
}
PK ]ZZZ��� 9 9 sympy/assumptions/assume.py"""A module which implements predicates and assumption context."""
from contextlib import contextmanager
import inspect
from sympy.core.symbol import Str
from sympy.core.sympify import _sympify
from sympy.logic.boolalg import Boolean, false, true
from sympy.multipledispatch.dispatcher import Dispatcher, str_signature
from sympy.utilities.exceptions import sympy_deprecation_warning
from sympy.utilities.iterables import is_sequence
from sympy.utilities.source import get_class
class AssumptionsContext(set):
"""
Set containing default assumptions which are applied to the ``ask()``
function.
Explanation
===========
This is used to represent global assumptions, but you can also use this
class to create your own local assumptions contexts. It is basically a thin
wrapper to Python's set, so see its documentation for advanced usage.
Examples
========
The default assumption context is ``global_assumptions``, which is initially empty:
>>> from sympy import ask, Q
>>> from sympy.assumptions import global_assumptions
>>> global_assumptions
AssumptionsContext()
You can add default assumptions:
>>> from sympy.abc import x
>>> global_assumptions.add(Q.real(x))
>>> global_assumptions
AssumptionsContext({Q.real(x)})
>>> ask(Q.real(x))
True
And remove them:
>>> global_assumptions.remove(Q.real(x))
>>> print(ask(Q.real(x)))
None
The ``clear()`` method removes every assumption:
>>> global_assumptions.add(Q.positive(x))
>>> global_assumptions
AssumptionsContext({Q.positive(x)})
>>> global_assumptions.clear()
>>> global_assumptions
AssumptionsContext()
See Also
========
assuming
"""
def add(self, *assumptions):
"""Add assumptions."""
for a in assumptions:
super().add(a)
def _sympystr(self, printer):
if not self:
return "%s()" % self.__class__.__name__
return "{}({})".format(self.__class__.__name__, printer._print_set(self))
global_assumptions = AssumptionsContext()
class AppliedPredicate(Boolean):
"""
The class of expressions resulting from applying ``Predicate`` to
the arguments. ``AppliedPredicate`` merely wraps its argument and
remain unevaluated. To evaluate it, use the ``ask()`` function.
Examples
========
>>> from sympy import Q, ask
>>> Q.integer(1)
Q.integer(1)
The ``function`` attribute returns the predicate, and the ``arguments``
attribute returns the tuple of arguments.
>>> type(Q.integer(1))
<class 'sympy.assumptions.assume.AppliedPredicate'>
>>> Q.integer(1).function
Q.integer
>>> Q.integer(1).arguments
(1,)
Applied predicates can be evaluated to a boolean value with ``ask``:
>>> ask(Q.integer(1))
True
"""
__slots__ = ()
def __new__(cls, predicate, *args):
if not isinstance(predicate, Predicate):
raise TypeError("%s is not a Predicate." % predicate)
args = map(_sympify, args)
return super().__new__(cls, predicate, *args)
@property
def arg(self):
"""
Return the expression used by this assumption.
Examples
========
>>> from sympy import Q, Symbol
>>> x = Symbol('x')
>>> a = Q.integer(x + 1)
>>> a.arg
x + 1
"""
# Will be deprecated
args = self._args
if len(args) == 2:
# backwards compatibility
return args[1]
raise TypeError("'arg' property is allowed only for unary predicates.")
@property
def function(self):
"""
Return the predicate.
"""
# Will be changed to self.args[0] after args overriding is removed
return self._args[0]
@property
def arguments(self):
"""
Return the arguments which are applied to the predicate.
"""
# Will be changed to self.args[1:] after args overriding is removed
return self._args[1:]
def _eval_ask(self, assumptions):
return self.function.eval(self.arguments, assumptions)
@property
def binary_symbols(self):
from .ask import Q
if self.function == Q.is_true:
i = self.arguments[0]
if i.is_Boolean or i.is_Symbol:
return i.binary_symbols
if self.function in (Q.eq, Q.ne):
if true in self.arguments or false in self.arguments:
if self.arguments[0].is_Symbol:
return {self.arguments[0]}
elif self.arguments[1].is_Symbol:
return {self.arguments[1]}
return set()
class PredicateMeta(type):
def __new__(cls, clsname, bases, dct):
# If handler is not defined, assign empty dispatcher.
if "handler" not in dct:
name = f"Ask{clsname.capitalize()}Handler"
handler = Dispatcher(name, doc="Handler for key %s" % name)
dct["handler"] = handler
dct["_orig_doc"] = dct.get("__doc__", "")
return super().__new__(cls, clsname, bases, dct)
@property
def __doc__(cls):
handler = cls.handler
doc = cls._orig_doc
if cls is not Predicate and handler is not None:
doc += "Handler\n"
doc += " =======\n\n"
# Append the handler's doc without breaking sphinx documentation.
docs = [" Multiply dispatched method: %s" % handler.name]
if handler.doc:
for line in handler.doc.splitlines():
if not line:
continue
docs.append(" %s" % line)
other = []
for sig in handler.ordering[::-1]:
func = handler.funcs[sig]
if func.__doc__:
s = ' Inputs: <%s>' % str_signature(sig)
lines = []
for line in func.__doc__.splitlines():
lines.append(" %s" % line)
s += "\n".join(lines)
docs.append(s)
else:
other.append(str_signature(sig))
if other:
othersig = " Other signatures:"
for line in other:
othersig += "\n * %s" % line
docs.append(othersig)
doc += '\n\n'.join(docs)
return doc
class Predicate(Boolean, metaclass=PredicateMeta):
"""
Base class for mathematical predicates. It also serves as a
constructor for undefined predicate objects.
Explanation
===========
Predicate is a function that returns a boolean value [1].
Predicate function is object, and it is instance of predicate class.
When a predicate is applied to arguments, ``AppliedPredicate``
instance is returned. This merely wraps the argument and remain
unevaluated. To obtain the truth value of applied predicate, use the
function ``ask``.
Evaluation of predicate is done by multiple dispatching. You can
register new handler to the predicate to support new types.
Every predicate in SymPy can be accessed via the property of ``Q``.
For example, ``Q.even`` returns the predicate which checks if the
argument is even number.
To define a predicate which can be evaluated, you must subclass this
class, make an instance of it, and register it to ``Q``. After then,
dispatch the handler by argument types.
If you directly construct predicate using this class, you will get
``UndefinedPredicate`` which cannot be dispatched. This is useful
when you are building boolean expressions which do not need to be
evaluated.
Examples
========
Applying and evaluating to boolean value:
>>> from sympy import Q, ask
>>> ask(Q.prime(7))
True
You can define a new predicate by subclassing and dispatching. Here,
we define a predicate for sexy primes [2] as an example.
>>> from sympy import Predicate, Integer
>>> class SexyPrimePredicate(Predicate):
... name = "sexyprime"
>>> Q.sexyprime = SexyPrimePredicate()
>>> @Q.sexyprime.register(Integer, Integer)
... def _(int1, int2, assumptions):
... args = sorted([int1, int2])
... if not all(ask(Q.prime(a), assumptions) for a in args):
... return False
... return args[1] - args[0] == 6
>>> ask(Q.sexyprime(5, 11))
True
Direct constructing returns ``UndefinedPredicate``, which can be
applied but cannot be dispatched.
>>> from sympy import Predicate, Integer
>>> Q.P = Predicate("P")
>>> type(Q.P)
<class 'sympy.assumptions.assume.UndefinedPredicate'>
>>> Q.P(1)
Q.P(1)
>>> Q.P.register(Integer)(lambda expr, assump: True)
Traceback (most recent call last):
...
TypeError: <class 'sympy.assumptions.assume.UndefinedPredicate'> cannot be dispatched.
References
==========
.. [1] https://en.wikipedia.org/wiki/Predicate_%28mathematical_logic%29
.. [2] https://en.wikipedia.org/wiki/Sexy_prime
"""
is_Atom = True
def __new__(cls, *args, **kwargs):
if cls is Predicate:
return UndefinedPredicate(*args, **kwargs)
obj = super().__new__(cls, *args)
return obj
@property
def name(self):
# May be overridden
return type(self).__name__
@classmethod
def register(cls, *types, **kwargs):
"""
Register the signature to the handler.
"""
if cls.handler is None:
raise TypeError("%s cannot be dispatched." % type(cls))
return cls.handler.register(*types, **kwargs)
@classmethod
def register_many(cls, *types, **kwargs):
"""
Register multiple signatures to same handler.
"""
def _(func):
for t in types:
if not is_sequence(t):
t = (t,) # for convenience, allow passing `type` to mean `(type,)`
cls.register(*t, **kwargs)(func)
return _
def __call__(self, *args):
return AppliedPredicate(self, *args)
def eval(self, args, assumptions=True):
"""
Evaluate ``self(*args)`` under the given assumptions.
This uses only direct resolution methods, not logical inference.
"""
result = None
try:
result = self.handler(*args, assumptions=assumptions)
except NotImplementedError:
pass
return result
def _eval_refine(self, assumptions):
# When Predicate is no longer Boolean, delete this method
return self
class UndefinedPredicate(Predicate):
"""
Predicate without handler.
Explanation
===========
This predicate is generated by using ``Predicate`` directly for
construction. It does not have a handler, and evaluating this with
arguments is done by SAT solver.
Examples
========
>>> from sympy import Predicate, Q
>>> Q.P = Predicate('P')
>>> Q.P.func
<class 'sympy.assumptions.assume.UndefinedPredicate'>
>>> Q.P.name
Str('P')
"""
handler = None
def __new__(cls, name, handlers=None):
# "handlers" parameter supports old design
if not isinstance(name, Str):
name = Str(name)
obj = super(Boolean, cls).__new__(cls, name)
obj.handlers = handlers or []
return obj
@property
def name(self):
return self.args[0]
def _hashable_content(self):
return (self.name,)
def __getnewargs__(self):
return (self.name,)
def __call__(self, expr):
return AppliedPredicate(self, expr)
def add_handler(self, handler):
sympy_deprecation_warning(
"""
The AskHandler system is deprecated. Predicate.add_handler()
should be replaced with the multipledispatch handler of Predicate.
""",
deprecated_since_version="1.8",
active_deprecations_target='deprecated-askhandler',
)
self.handlers.append(handler)
def remove_handler(self, handler):
sympy_deprecation_warning(
"""
The AskHandler system is deprecated. Predicate.remove_handler()
should be replaced with the multipledispatch handler of Predicate.
""",
deprecated_since_version="1.8",
active_deprecations_target='deprecated-askhandler',
)
self.handlers.remove(handler)
def eval(self, args, assumptions=True):
# Support for deprecated design
# When old design is removed, this will always return None
sympy_deprecation_warning(
"""
The AskHandler system is deprecated. Evaluating UndefinedPredicate
objects should be replaced with the multipledispatch handler of
Predicate.
""",
deprecated_since_version="1.8",
active_deprecations_target='deprecated-askhandler',
stacklevel=5,
)
expr, = args
res, _res = None, None
mro = inspect.getmro(type(expr))
for handler in self.handlers:
cls = get_class(handler)
for subclass in mro:
eval_ = getattr(cls, subclass.__name__, None)
if eval_ is None:
continue
res = eval_(expr, assumptions)
# Do not stop if value returned is None
# Try to check for higher classes
if res is None:
continue
if _res is None:
_res = res
else:
# only check consistency if both resolutors have concluded
if _res != res:
raise ValueError('incompatible resolutors')
break
return res
@contextmanager
def assuming(*assumptions):
"""
Context manager for assumptions.
Examples
========
>>> from sympy import assuming, Q, ask
>>> from sympy.abc import x, y
>>> print(ask(Q.integer(x + y)))
None
>>> with assuming(Q.integer(x), Q.integer(y)):
... print(ask(Q.integer(x + y)))
True
"""
old_global_assumptions = global_assumptions.copy()
global_assumptions.update(assumptions)
try:
yield
finally:
global_assumptions.clear()
global_assumptions.update(old_global_assumptions)
PK ]ZZZ-A�S�0 �0 sympy/assumptions/cnf.py"""
The classes used here are for the internal use of assumptions system
only and should not be used anywhere else as these do not possess the
signatures common to SymPy objects. For general use of logic constructs
please refer to sympy.logic classes And, Or, Not, etc.
"""
from itertools import combinations, product, zip_longest
from sympy.assumptions.assume import AppliedPredicate, Predicate
from sympy.core.relational import Eq, Ne, Gt, Lt, Ge, Le
from sympy.core.singleton import S
from sympy.logic.boolalg import Or, And, Not, Xnor
from sympy.logic.boolalg import (Equivalent, ITE, Implies, Nand, Nor, Xor)
class Literal:
"""
The smallest element of a CNF object.
Parameters
==========
lit : Boolean expression
is_Not : bool
Examples
========
>>> from sympy import Q
>>> from sympy.assumptions.cnf import Literal
>>> from sympy.abc import x
>>> Literal(Q.even(x))
Literal(Q.even(x), False)
>>> Literal(~Q.even(x))
Literal(Q.even(x), True)
"""
def __new__(cls, lit, is_Not=False):
if isinstance(lit, Not):
lit = lit.args[0]
is_Not = True
elif isinstance(lit, (AND, OR, Literal)):
return ~lit if is_Not else lit
obj = super().__new__(cls)
obj.lit = lit
obj.is_Not = is_Not
return obj
@property
def arg(self):
return self.lit
def rcall(self, expr):
if callable(self.lit):
lit = self.lit(expr)
else:
lit = self.lit.apply(expr)
return type(self)(lit, self.is_Not)
def __invert__(self):
is_Not = not self.is_Not
return Literal(self.lit, is_Not)
def __str__(self):
return '{}({}, {})'.format(type(self).__name__, self.lit, self.is_Not)
__repr__ = __str__
def __eq__(self, other):
return self.arg == other.arg and self.is_Not == other.is_Not
def __hash__(self):
h = hash((type(self).__name__, self.arg, self.is_Not))
return h
class OR:
"""
A low-level implementation for Or
"""
def __init__(self, *args):
self._args = args
@property
def args(self):
return sorted(self._args, key=str)
def rcall(self, expr):
return type(self)(*[arg.rcall(expr)
for arg in self._args
])
def __invert__(self):
return AND(*[~arg for arg in self._args])
def __hash__(self):
return hash((type(self).__name__,) + tuple(self.args))
def __eq__(self, other):
return self.args == other.args
def __str__(self):
s = '(' + ' | '.join([str(arg) for arg in self.args]) + ')'
return s
__repr__ = __str__
class AND:
"""
A low-level implementation for And
"""
def __init__(self, *args):
self._args = args
def __invert__(self):
return OR(*[~arg for arg in self._args])
@property
def args(self):
return sorted(self._args, key=str)
def rcall(self, expr):
return type(self)(*[arg.rcall(expr)
for arg in self._args
])
def __hash__(self):
return hash((type(self).__name__,) + tuple(self.args))
def __eq__(self, other):
return self.args == other.args
def __str__(self):
s = '('+' & '.join([str(arg) for arg in self.args])+')'
return s
__repr__ = __str__
def to_NNF(expr, composite_map=None):
"""
Generates the Negation Normal Form of any boolean expression in terms
of AND, OR, and Literal objects.
Examples
========
>>> from sympy import Q, Eq
>>> from sympy.assumptions.cnf import to_NNF
>>> from sympy.abc import x, y
>>> expr = Q.even(x) & ~Q.positive(x)
>>> to_NNF(expr)
(Literal(Q.even(x), False) & Literal(Q.positive(x), True))
Supported boolean objects are converted to corresponding predicates.
>>> to_NNF(Eq(x, y))
Literal(Q.eq(x, y), False)
If ``composite_map`` argument is given, ``to_NNF`` decomposes the
specified predicate into a combination of primitive predicates.
>>> cmap = {Q.nonpositive: Q.negative | Q.zero}
>>> to_NNF(Q.nonpositive, cmap)
(Literal(Q.negative, False) | Literal(Q.zero, False))
>>> to_NNF(Q.nonpositive(x), cmap)
(Literal(Q.negative(x), False) | Literal(Q.zero(x), False))
"""
from sympy.assumptions.ask import Q
if composite_map is None:
composite_map = {}
binrelpreds = {Eq: Q.eq, Ne: Q.ne, Gt: Q.gt, Lt: Q.lt, Ge: Q.ge, Le: Q.le}
if type(expr) in binrelpreds:
pred = binrelpreds[type(expr)]
expr = pred(*expr.args)
if isinstance(expr, Not):
arg = expr.args[0]
tmp = to_NNF(arg, composite_map) # Strategy: negate the NNF of expr
return ~tmp
if isinstance(expr, Or):
return OR(*[to_NNF(x, composite_map) for x in Or.make_args(expr)])
if isinstance(expr, And):
return AND(*[to_NNF(x, composite_map) for x in And.make_args(expr)])
if isinstance(expr, Nand):
tmp = AND(*[to_NNF(x, composite_map) for x in expr.args])
return ~tmp
if isinstance(expr, Nor):
tmp = OR(*[to_NNF(x, composite_map) for x in expr.args])
return ~tmp
if isinstance(expr, Xor):
cnfs = []
for i in range(0, len(expr.args) + 1, 2):
for neg in combinations(expr.args, i):
clause = [~to_NNF(s, composite_map) if s in neg else to_NNF(s, composite_map)
for s in expr.args]
cnfs.append(OR(*clause))
return AND(*cnfs)
if isinstance(expr, Xnor):
cnfs = []
for i in range(0, len(expr.args) + 1, 2):
for neg in combinations(expr.args, i):
clause = [~to_NNF(s, composite_map) if s in neg else to_NNF(s, composite_map)
for s in expr.args]
cnfs.append(OR(*clause))
return ~AND(*cnfs)
if isinstance(expr, Implies):
L, R = to_NNF(expr.args[0], composite_map), to_NNF(expr.args[1], composite_map)
return OR(~L, R)
if isinstance(expr, Equivalent):
cnfs = []
for a, b in zip_longest(expr.args, expr.args[1:], fillvalue=expr.args[0]):
a = to_NNF(a, composite_map)
b = to_NNF(b, composite_map)
cnfs.append(OR(~a, b))
return AND(*cnfs)
if isinstance(expr, ITE):
L = to_NNF(expr.args[0], composite_map)
M = to_NNF(expr.args[1], composite_map)
R = to_NNF(expr.args[2], composite_map)
return AND(OR(~L, M), OR(L, R))
if isinstance(expr, AppliedPredicate):
pred, args = expr.function, expr.arguments
newpred = composite_map.get(pred, None)
if newpred is not None:
return to_NNF(newpred.rcall(*args), composite_map)
if isinstance(expr, Predicate):
newpred = composite_map.get(expr, None)
if newpred is not None:
return to_NNF(newpred, composite_map)
return Literal(expr)
def distribute_AND_over_OR(expr):
"""
Distributes AND over OR in the NNF expression.
Returns the result( Conjunctive Normal Form of expression)
as a CNF object.
"""
if not isinstance(expr, (AND, OR)):
tmp = set()
tmp.add(frozenset((expr,)))
return CNF(tmp)
if isinstance(expr, OR):
return CNF.all_or(*[distribute_AND_over_OR(arg)
for arg in expr._args])
if isinstance(expr, AND):
return CNF.all_and(*[distribute_AND_over_OR(arg)
for arg in expr._args])
class CNF:
"""
Class to represent CNF of a Boolean expression.
Consists of set of clauses, which themselves are stored as
frozenset of Literal objects.
Examples
========
>>> from sympy import Q
>>> from sympy.assumptions.cnf import CNF
>>> from sympy.abc import x
>>> cnf = CNF.from_prop(Q.real(x) & ~Q.zero(x))
>>> cnf.clauses
{frozenset({Literal(Q.zero(x), True)}),
frozenset({Literal(Q.negative(x), False),
Literal(Q.positive(x), False), Literal(Q.zero(x), False)})}
"""
def __init__(self, clauses=None):
if not clauses:
clauses = set()
self.clauses = clauses
def add(self, prop):
clauses = CNF.to_CNF(prop).clauses
self.add_clauses(clauses)
def __str__(self):
s = ' & '.join(
['(' + ' | '.join([str(lit) for lit in clause]) +')'
for clause in self.clauses]
)
return s
def extend(self, props):
for p in props:
self.add(p)
return self
def copy(self):
return CNF(set(self.clauses))
def add_clauses(self, clauses):
self.clauses |= clauses
@classmethod
def from_prop(cls, prop):
res = cls()
res.add(prop)
return res
def __iand__(self, other):
self.add_clauses(other.clauses)
return self
def all_predicates(self):
predicates = set()
for c in self.clauses:
predicates |= {arg.lit for arg in c}
return predicates
def _or(self, cnf):
clauses = set()
for a, b in product(self.clauses, cnf.clauses):
tmp = set(a)
tmp.update(b)
clauses.add(frozenset(tmp))
return CNF(clauses)
def _and(self, cnf):
clauses = self.clauses.union(cnf.clauses)
return CNF(clauses)
def _not(self):
clss = list(self.clauses)
ll = {frozenset((~x,)) for x in clss[-1]}
ll = CNF(ll)
for rest in clss[:-1]:
p = {frozenset((~x,)) for x in rest}
ll = ll._or(CNF(p))
return ll
def rcall(self, expr):
clause_list = []
for clause in self.clauses:
lits = [arg.rcall(expr) for arg in clause]
clause_list.append(OR(*lits))
expr = AND(*clause_list)
return distribute_AND_over_OR(expr)
@classmethod
def all_or(cls, *cnfs):
b = cnfs[0].copy()
for rest in cnfs[1:]:
b = b._or(rest)
return b
@classmethod
def all_and(cls, *cnfs):
b = cnfs[0].copy()
for rest in cnfs[1:]:
b = b._and(rest)
return b
@classmethod
def to_CNF(cls, expr):
from sympy.assumptions.facts import get_composite_predicates
expr = to_NNF(expr, get_composite_predicates())
expr = distribute_AND_over_OR(expr)
return expr
@classmethod
def CNF_to_cnf(cls, cnf):
"""
Converts CNF object to SymPy's boolean expression
retaining the form of expression.
"""
def remove_literal(arg):
return Not(arg.lit) if arg.is_Not else arg.lit
return And(*(Or(*(remove_literal(arg) for arg in clause)) for clause in cnf.clauses))
class EncodedCNF:
"""
Class for encoding the CNF expression.
"""
def __init__(self, data=None, encoding=None):
if not data and not encoding:
data = []
encoding = {}
self.data = data
self.encoding = encoding
self._symbols = list(encoding.keys())
def from_cnf(self, cnf):
self._symbols = list(cnf.all_predicates())
n = len(self._symbols)
self.encoding = dict(zip(self._symbols, range(1, n + 1)))
self.data = [self.encode(clause) for clause in cnf.clauses]
@property
def symbols(self):
return self._symbols
@property
def variables(self):
return range(1, len(self._symbols) + 1)
def copy(self):
new_data = [set(clause) for clause in self.data]
return EncodedCNF(new_data, dict(self.encoding))
def add_prop(self, prop):
cnf = CNF.from_prop(prop)
self.add_from_cnf(cnf)
def add_from_cnf(self, cnf):
clauses = [self.encode(clause) for clause in cnf.clauses]
self.data += clauses
def encode_arg(self, arg):
literal = arg.lit
value = self.encoding.get(literal, None)
if value is None:
n = len(self._symbols)
self._symbols.append(literal)
value = self.encoding[literal] = n + 1
if arg.is_Not:
return -value
else:
return value
def encode(self, clause):
return {self.encode_arg(arg) if not arg.lit == S.false else 0 for arg in clause}
PK ]ZZZ��� � sympy/assumptions/facts.py"""
Known facts in assumptions module.
This module defines the facts between unary predicates in ``get_known_facts()``,
and supports functions to generate the contents in
``sympy.assumptions.ask_generated`` file.
"""
from sympy.assumptions.ask import Q
from sympy.assumptions.assume import AppliedPredicate
from sympy.core.cache import cacheit
from sympy.core.symbol import Symbol
from sympy.logic.boolalg import (to_cnf, And, Not, Implies, Equivalent,
Exclusive,)
from sympy.logic.inference import satisfiable
@cacheit
def get_composite_predicates():
# To reduce the complexity of sat solver, these predicates are
# transformed into the combination of primitive predicates.
return {
Q.real : Q.negative | Q.zero | Q.positive,
Q.integer : Q.even | Q.odd,
Q.nonpositive : Q.negative | Q.zero,
Q.nonzero : Q.negative | Q.positive,
Q.nonnegative : Q.zero | Q.positive,
Q.extended_real : Q.negative_infinite | Q.negative | Q.zero | Q.positive | Q.positive_infinite,
Q.extended_positive: Q.positive | Q.positive_infinite,
Q.extended_negative: Q.negative | Q.negative_infinite,
Q.extended_nonzero: Q.negative_infinite | Q.negative | Q.positive | Q.positive_infinite,
Q.extended_nonpositive: Q.negative_infinite | Q.negative | Q.zero,
Q.extended_nonnegative: Q.zero | Q.positive | Q.positive_infinite,
Q.complex : Q.algebraic | Q.transcendental
}
@cacheit
def get_known_facts(x=None):
"""
Facts between unary predicates.
Parameters
==========
x : Symbol, optional
Placeholder symbol for unary facts. Default is ``Symbol('x')``.
Returns
=======
fact : Known facts in conjugated normal form.
"""
if x is None:
x = Symbol('x')
fact = And(
get_number_facts(x),
get_matrix_facts(x)
)
return fact
@cacheit
def get_number_facts(x = None):
"""
Facts between unary number predicates.
Parameters
==========
x : Symbol, optional
Placeholder symbol for unary facts. Default is ``Symbol('x')``.
Returns
=======
fact : Known facts in conjugated normal form.
"""
if x is None:
x = Symbol('x')
fact = And(
# primitive predicates for extended real exclude each other.
Exclusive(Q.negative_infinite(x), Q.negative(x), Q.zero(x),
Q.positive(x), Q.positive_infinite(x)),
# build complex plane
Exclusive(Q.real(x), Q.imaginary(x)),
Implies(Q.real(x) | Q.imaginary(x), Q.complex(x)),
# other subsets of complex
Exclusive(Q.transcendental(x), Q.algebraic(x)),
Equivalent(Q.real(x), Q.rational(x) | Q.irrational(x)),
Exclusive(Q.irrational(x), Q.rational(x)),
Implies(Q.rational(x), Q.algebraic(x)),
# integers
Exclusive(Q.even(x), Q.odd(x)),
Implies(Q.integer(x), Q.rational(x)),
Implies(Q.zero(x), Q.even(x)),
Exclusive(Q.composite(x), Q.prime(x)),
Implies(Q.composite(x) | Q.prime(x), Q.integer(x) & Q.positive(x)),
Implies(Q.even(x) & Q.positive(x) & ~Q.prime(x), Q.composite(x)),
# hermitian and antihermitian
Implies(Q.real(x), Q.hermitian(x)),
Implies(Q.imaginary(x), Q.antihermitian(x)),
Implies(Q.zero(x), Q.hermitian(x) | Q.antihermitian(x)),
# define finity and infinity, and build extended real line
Exclusive(Q.infinite(x), Q.finite(x)),
Implies(Q.complex(x), Q.finite(x)),
Implies(Q.negative_infinite(x) | Q.positive_infinite(x), Q.infinite(x)),
# commutativity
Implies(Q.finite(x) | Q.infinite(x), Q.commutative(x)),
)
return fact
@cacheit
def get_matrix_facts(x = None):
"""
Facts between unary matrix predicates.
Parameters
==========
x : Symbol, optional
Placeholder symbol for unary facts. Default is ``Symbol('x')``.
Returns
=======
fact : Known facts in conjugated normal form.
"""
if x is None:
x = Symbol('x')
fact = And(
# matrices
Implies(Q.orthogonal(x), Q.positive_definite(x)),
Implies(Q.orthogonal(x), Q.unitary(x)),
Implies(Q.unitary(x) & Q.real_elements(x), Q.orthogonal(x)),
Implies(Q.unitary(x), Q.normal(x)),
Implies(Q.unitary(x), Q.invertible(x)),
Implies(Q.normal(x), Q.square(x)),
Implies(Q.diagonal(x), Q.normal(x)),
Implies(Q.positive_definite(x), Q.invertible(x)),
Implies(Q.diagonal(x), Q.upper_triangular(x)),
Implies(Q.diagonal(x), Q.lower_triangular(x)),
Implies(Q.lower_triangular(x), Q.triangular(x)),
Implies(Q.upper_triangular(x), Q.triangular(x)),
Implies(Q.triangular(x), Q.upper_triangular(x) | Q.lower_triangular(x)),
Implies(Q.upper_triangular(x) & Q.lower_triangular(x), Q.diagonal(x)),
Implies(Q.diagonal(x), Q.symmetric(x)),
Implies(Q.unit_triangular(x), Q.triangular(x)),
Implies(Q.invertible(x), Q.fullrank(x)),
Implies(Q.invertible(x), Q.square(x)),
Implies(Q.symmetric(x), Q.square(x)),
Implies(Q.fullrank(x) & Q.square(x), Q.invertible(x)),
Equivalent(Q.invertible(x), ~Q.singular(x)),
Implies(Q.integer_elements(x), Q.real_elements(x)),
Implies(Q.real_elements(x), Q.complex_elements(x)),
)
return fact
def generate_known_facts_dict(keys, fact):
"""
Computes and returns a dictionary which contains the relations between
unary predicates.
Each key is a predicate, and item is two groups of predicates.
First group contains the predicates which are implied by the key, and
second group contains the predicates which are rejected by the key.
All predicates in *keys* and *fact* must be unary and have same placeholder
symbol.
Parameters
==========
keys : list of AppliedPredicate instances.
fact : Fact between predicates in conjugated normal form.
Examples
========
>>> from sympy import Q, And, Implies
>>> from sympy.assumptions.facts import generate_known_facts_dict
>>> from sympy.abc import x
>>> keys = [Q.even(x), Q.odd(x), Q.zero(x)]
>>> fact = And(Implies(Q.even(x), ~Q.odd(x)),
... Implies(Q.zero(x), Q.even(x)))
>>> generate_known_facts_dict(keys, fact)
{Q.even: ({Q.even}, {Q.odd}),
Q.odd: ({Q.odd}, {Q.even, Q.zero}),
Q.zero: ({Q.even, Q.zero}, {Q.odd})}
"""
fact_cnf = to_cnf(fact)
mapping = single_fact_lookup(keys, fact_cnf)
ret = {}
for key, value in mapping.items():
implied = set()
rejected = set()
for expr in value:
if isinstance(expr, AppliedPredicate):
implied.add(expr.function)
elif isinstance(expr, Not):
pred = expr.args[0]
rejected.add(pred.function)
ret[key.function] = (implied, rejected)
return ret
@cacheit
def get_known_facts_keys():
"""
Return every unary predicates registered to ``Q``.
This function is used to generate the keys for
``generate_known_facts_dict``.
"""
# exclude polyadic predicates
exclude = {Q.eq, Q.ne, Q.gt, Q.lt, Q.ge, Q.le}
result = []
for attr in Q.__class__.__dict__:
if attr.startswith('__'):
continue
pred = getattr(Q, attr)
if pred in exclude:
continue
result.append(pred)
return result
def single_fact_lookup(known_facts_keys, known_facts_cnf):
# Return the dictionary for quick lookup of single fact
mapping = {}
for key in known_facts_keys:
mapping[key] = {key}
for other_key in known_facts_keys:
if other_key != key:
if ask_full_inference(other_key, key, known_facts_cnf):
mapping[key].add(other_key)
if ask_full_inference(~other_key, key, known_facts_cnf):
mapping[key].add(~other_key)
return mapping
def ask_full_inference(proposition, assumptions, known_facts_cnf):
"""
Method for inferring properties about objects.
"""
if not satisfiable(And(known_facts_cnf, assumptions, proposition)):
return False
if not satisfiable(And(known_facts_cnf, assumptions, Not(proposition))):
return True
return None
PK ]ZZZ �n,[% [% sympy/assumptions/lra_satask.pyfrom sympy.assumptions.assume import global_assumptions
from sympy.assumptions.cnf import CNF, EncodedCNF
from sympy.assumptions.ask import Q
from sympy.logic.inference import satisfiable
from sympy.logic.algorithms.lra_theory import UnhandledInput, ALLOWED_PRED
from sympy.matrices.kind import MatrixKind
from sympy.core.kind import NumberKind
from sympy.assumptions.assume import AppliedPredicate
from sympy.core.mul import Mul
from sympy.core.singleton import S
def lra_satask(proposition, assumptions=True, context=global_assumptions):
"""
Function to evaluate the proposition with assumptions using SAT algorithm
in conjunction with an Linear Real Arithmetic theory solver.
Used to handle inequalities. Should eventually be depreciated and combined
into satask, but infinity handling and other things need to be implemented
before that can happen.
"""
props = CNF.from_prop(proposition)
_props = CNF.from_prop(~proposition)
cnf = CNF.from_prop(assumptions)
assumptions = EncodedCNF()
assumptions.from_cnf(cnf)
context_cnf = CNF()
if context:
context_cnf = context_cnf.extend(context)
assumptions.add_from_cnf(context_cnf)
return check_satisfiability(props, _props, assumptions)
# Some predicates such as Q.prime can't be handled by lra_satask.
# For example, (x > 0) & (x < 1) & Q.prime(x) is unsat but lra_satask would think it was sat.
# WHITE_LIST is a list of predicates that can always be handled.
WHITE_LIST = ALLOWED_PRED | {Q.positive, Q.negative, Q.zero, Q.nonzero, Q.nonpositive, Q.nonnegative,
Q.extended_positive, Q.extended_negative, Q.extended_nonpositive,
Q.extended_negative, Q.extended_nonzero, Q.negative_infinite,
Q.positive_infinite}
def check_satisfiability(prop, _prop, factbase):
sat_true = factbase.copy()
sat_false = factbase.copy()
sat_true.add_from_cnf(prop)
sat_false.add_from_cnf(_prop)
all_pred, all_exprs = get_all_pred_and_expr_from_enc_cnf(sat_true)
for pred in all_pred:
if pred.function not in WHITE_LIST and pred.function != Q.ne:
raise UnhandledInput(f"LRASolver: {pred} is an unhandled predicate")
for expr in all_exprs:
if expr.kind == MatrixKind(NumberKind):
raise UnhandledInput(f"LRASolver: {expr} is of MatrixKind")
if expr == S.NaN:
raise UnhandledInput("LRASolver: nan")
# convert old assumptions into predicates and add them to sat_true and sat_false
# also check for unhandled predicates
for assm in extract_pred_from_old_assum(all_exprs):
n = len(sat_true.encoding)
if assm not in sat_true.encoding:
sat_true.encoding[assm] = n+1
sat_true.data.append([sat_true.encoding[assm]])
n = len(sat_false.encoding)
if assm not in sat_false.encoding:
sat_false.encoding[assm] = n+1
sat_false.data.append([sat_false.encoding[assm]])
sat_true = _preprocess(sat_true)
sat_false = _preprocess(sat_false)
can_be_true = satisfiable(sat_true, use_lra_theory=True) is not False
can_be_false = satisfiable(sat_false, use_lra_theory=True) is not False
if can_be_true and can_be_false:
return None
if can_be_true and not can_be_false:
return True
if not can_be_true and can_be_false:
return False
if not can_be_true and not can_be_false:
raise ValueError("Inconsistent assumptions")
def _preprocess(enc_cnf):
"""
Returns an encoded cnf with only Q.eq, Q.gt, Q.lt,
Q.ge, and Q.le predicate.
Converts every unequality into a disjunction of strict
inequalities. For example, x != 3 would become
x < 3 OR x > 3.
Also converts all negated Q.ne predicates into
equalities.
"""
# loops through each literal in each clause
# to construct a new, preprocessed encodedCNF
enc_cnf = enc_cnf.copy()
cur_enc = 1
rev_encoding = {value: key for key, value in enc_cnf.encoding.items()}
new_encoding = {}
new_data = []
for clause in enc_cnf.data:
new_clause = []
for lit in clause:
if lit == 0:
new_clause.append(lit)
new_encoding[lit] = False
continue
prop = rev_encoding[abs(lit)]
negated = lit < 0
sign = (lit > 0) - (lit < 0)
prop = _pred_to_binrel(prop)
if not isinstance(prop, AppliedPredicate):
if prop not in new_encoding:
new_encoding[prop] = cur_enc
cur_enc += 1
lit = new_encoding[prop]
new_clause.append(sign*lit)
continue
if negated and prop.function == Q.eq:
negated = False
prop = Q.ne(*prop.arguments)
if prop.function == Q.ne:
arg1, arg2 = prop.arguments
if negated:
new_prop = Q.eq(arg1, arg2)
if new_prop not in new_encoding:
new_encoding[new_prop] = cur_enc
cur_enc += 1
new_enc = new_encoding[new_prop]
new_clause.append(new_enc)
continue
else:
new_props = (Q.gt(arg1, arg2), Q.lt(arg1, arg2))
for new_prop in new_props:
if new_prop not in new_encoding:
new_encoding[new_prop] = cur_enc
cur_enc += 1
new_enc = new_encoding[new_prop]
new_clause.append(new_enc)
continue
if prop.function == Q.eq and negated:
assert False
if prop not in new_encoding:
new_encoding[prop] = cur_enc
cur_enc += 1
new_clause.append(new_encoding[prop]*sign)
new_data.append(new_clause)
assert len(new_encoding) >= cur_enc - 1
enc_cnf = EncodedCNF(new_data, new_encoding)
return enc_cnf
def _pred_to_binrel(pred):
if not isinstance(pred, AppliedPredicate):
return pred
if pred.function in pred_to_pos_neg_zero:
f = pred_to_pos_neg_zero[pred.function]
if f is False:
return False
pred = f(pred.arguments[0])
if pred.function == Q.positive:
pred = Q.gt(pred.arguments[0], 0)
elif pred.function == Q.negative:
pred = Q.lt(pred.arguments[0], 0)
elif pred.function == Q.zero:
pred = Q.eq(pred.arguments[0], 0)
elif pred.function == Q.nonpositive:
pred = Q.le(pred.arguments[0], 0)
elif pred.function == Q.nonnegative:
pred = Q.ge(pred.arguments[0], 0)
elif pred.function == Q.nonzero:
pred = Q.ne(pred.arguments[0], 0)
return pred
pred_to_pos_neg_zero = {
Q.extended_positive: Q.positive,
Q.extended_negative: Q.negative,
Q.extended_nonpositive: Q.nonpositive,
Q.extended_negative: Q.negative,
Q.extended_nonzero: Q.nonzero,
Q.negative_infinite: False,
Q.positive_infinite: False
}
def get_all_pred_and_expr_from_enc_cnf(enc_cnf):
all_exprs = set()
all_pred = set()
for pred in enc_cnf.encoding.keys():
if isinstance(pred, AppliedPredicate):
all_pred.add(pred)
all_exprs.update(pred.arguments)
return all_pred, all_exprs
def extract_pred_from_old_assum(all_exprs):
"""
Returns a list of relevant new assumption predicate
based on any old assumptions.
Raises an UnhandledInput exception if any of the assumptions are
unhandled.
Ignored predicate:
- commutative
- complex
- algebraic
- transcendental
- extended_real
- real
- all matrix predicate
- rational
- irrational
Example
=======
>>> from sympy.assumptions.lra_satask import extract_pred_from_old_assum
>>> from sympy import symbols
>>> x, y = symbols("x y", positive=True)
>>> extract_pred_from_old_assum([x, y, 2])
[Q.positive(x), Q.positive(y)]
"""
ret = []
for expr in all_exprs:
if not hasattr(expr, "free_symbols"):
continue
if len(expr.free_symbols) == 0:
continue
if expr.is_real is not True:
raise UnhandledInput(f"LRASolver: {expr} must be real")
# test for I times imaginary variable; such expressions are considered real
if isinstance(expr, Mul) and any(arg.is_real is not True for arg in expr.args):
raise UnhandledInput(f"LRASolver: {expr} must be real")
if expr.is_integer == True and expr.is_zero != True:
raise UnhandledInput(f"LRASolver: {expr} is an integer")
if expr.is_integer == False:
raise UnhandledInput(f"LRASolver: {expr} can't be an integer")
if expr.is_rational == False:
raise UnhandledInput(f"LRASolver: {expr} is irational")
if expr.is_zero:
ret.append(Q.zero(expr))
elif expr.is_positive:
ret.append(Q.positive(expr))
elif expr.is_negative:
ret.append(Q.negative(expr))
elif expr.is_nonzero:
ret.append(Q.nonzero(expr))
elif expr.is_nonpositive:
ret.append(Q.nonpositive(expr))
elif expr.is_nonnegative:
ret.append(Q.nonnegative(expr))
return ret
PK ]ZZZ��q(�. �. sympy/assumptions/refine.pyfrom __future__ import annotations
from typing import Callable
from sympy.core import S, Add, Expr, Basic, Mul, Pow, Rational
from sympy.core.logic import fuzzy_not
from sympy.logic.boolalg import Boolean
from sympy.assumptions import ask, Q # type: ignore
def refine(expr, assumptions=True):
"""
Simplify an expression using assumptions.
Explanation
===========
Unlike :func:`~.simplify` which performs structural simplification
without any assumption, this function transforms the expression into
the form which is only valid under certain assumptions. Note that
``simplify()`` is generally not done in refining process.
Refining boolean expression involves reducing it to ``S.true`` or
``S.false``. Unlike :func:`~.ask`, the expression will not be reduced
if the truth value cannot be determined.
Examples
========
>>> from sympy import refine, sqrt, Q
>>> from sympy.abc import x
>>> refine(sqrt(x**2), Q.real(x))
Abs(x)
>>> refine(sqrt(x**2), Q.positive(x))
x
>>> refine(Q.real(x), Q.positive(x))
True
>>> refine(Q.positive(x), Q.real(x))
Q.positive(x)
See Also
========
sympy.simplify.simplify.simplify : Structural simplification without assumptions.
sympy.assumptions.ask.ask : Query for boolean expressions using assumptions.
"""
if not isinstance(expr, Basic):
return expr
if not expr.is_Atom:
args = [refine(arg, assumptions) for arg in expr.args]
# TODO: this will probably not work with Integral or Polynomial
expr = expr.func(*args)
if hasattr(expr, '_eval_refine'):
ref_expr = expr._eval_refine(assumptions)
if ref_expr is not None:
return ref_expr
name = expr.__class__.__name__
handler = handlers_dict.get(name, None)
if handler is None:
return expr
new_expr = handler(expr, assumptions)
if (new_expr is None) or (expr == new_expr):
return expr
if not isinstance(new_expr, Expr):
return new_expr
return refine(new_expr, assumptions)
def refine_abs(expr, assumptions):
"""
Handler for the absolute value.
Examples
========
>>> from sympy import Q, Abs
>>> from sympy.assumptions.refine import refine_abs
>>> from sympy.abc import x
>>> refine_abs(Abs(x), Q.real(x))
>>> refine_abs(Abs(x), Q.positive(x))
x
>>> refine_abs(Abs(x), Q.negative(x))
-x
"""
from sympy.functions.elementary.complexes import Abs
arg = expr.args[0]
if ask(Q.real(arg), assumptions) and \
fuzzy_not(ask(Q.negative(arg), assumptions)):
# if it's nonnegative
return arg
if ask(Q.negative(arg), assumptions):
return -arg
# arg is Mul
if isinstance(arg, Mul):
r = [refine(abs(a), assumptions) for a in arg.args]
non_abs = []
in_abs = []
for i in r:
if isinstance(i, Abs):
in_abs.append(i.args[0])
else:
non_abs.append(i)
return Mul(*non_abs) * Abs(Mul(*in_abs))
def refine_Pow(expr, assumptions):
"""
Handler for instances of Pow.
Examples
========
>>> from sympy import Q
>>> from sympy.assumptions.refine import refine_Pow
>>> from sympy.abc import x,y,z
>>> refine_Pow((-1)**x, Q.real(x))
>>> refine_Pow((-1)**x, Q.even(x))
1
>>> refine_Pow((-1)**x, Q.odd(x))
-1
For powers of -1, even parts of the exponent can be simplified:
>>> refine_Pow((-1)**(x+y), Q.even(x))
(-1)**y
>>> refine_Pow((-1)**(x+y+z), Q.odd(x) & Q.odd(z))
(-1)**y
>>> refine_Pow((-1)**(x+y+2), Q.odd(x))
(-1)**(y + 1)
>>> refine_Pow((-1)**(x+3), True)
(-1)**(x + 1)
"""
from sympy.functions.elementary.complexes import Abs
from sympy.functions import sign
if isinstance(expr.base, Abs):
if ask(Q.real(expr.base.args[0]), assumptions) and \
ask(Q.even(expr.exp), assumptions):
return expr.base.args[0] ** expr.exp
if ask(Q.real(expr.base), assumptions):
if expr.base.is_number:
if ask(Q.even(expr.exp), assumptions):
return abs(expr.base) ** expr.exp
if ask(Q.odd(expr.exp), assumptions):
return sign(expr.base) * abs(expr.base) ** expr.exp
if isinstance(expr.exp, Rational):
if isinstance(expr.base, Pow):
return abs(expr.base.base) ** (expr.base.exp * expr.exp)
if expr.base is S.NegativeOne:
if expr.exp.is_Add:
old = expr
# For powers of (-1) we can remove
# - even terms
# - pairs of odd terms
# - a single odd term + 1
# - A numerical constant N can be replaced with mod(N,2)
coeff, terms = expr.exp.as_coeff_add()
terms = set(terms)
even_terms = set()
odd_terms = set()
initial_number_of_terms = len(terms)
for t in terms:
if ask(Q.even(t), assumptions):
even_terms.add(t)
elif ask(Q.odd(t), assumptions):
odd_terms.add(t)
terms -= even_terms
if len(odd_terms) % 2:
terms -= odd_terms
new_coeff = (coeff + S.One) % 2
else:
terms -= odd_terms
new_coeff = coeff % 2
if new_coeff != coeff or len(terms) < initial_number_of_terms:
terms.add(new_coeff)
expr = expr.base**(Add(*terms))
# Handle (-1)**((-1)**n/2 + m/2)
e2 = 2*expr.exp
if ask(Q.even(e2), assumptions):
if e2.could_extract_minus_sign():
e2 *= expr.base
if e2.is_Add:
i, p = e2.as_two_terms()
if p.is_Pow and p.base is S.NegativeOne:
if ask(Q.integer(p.exp), assumptions):
i = (i + 1)/2
if ask(Q.even(i), assumptions):
return expr.base**p.exp
elif ask(Q.odd(i), assumptions):
return expr.base**(p.exp + 1)
else:
return expr.base**(p.exp + i)
if old != expr:
return expr
def refine_atan2(expr, assumptions):
"""
Handler for the atan2 function.
Examples
========
>>> from sympy import Q, atan2
>>> from sympy.assumptions.refine import refine_atan2
>>> from sympy.abc import x, y
>>> refine_atan2(atan2(y,x), Q.real(y) & Q.positive(x))
atan(y/x)
>>> refine_atan2(atan2(y,x), Q.negative(y) & Q.negative(x))
atan(y/x) - pi
>>> refine_atan2(atan2(y,x), Q.positive(y) & Q.negative(x))
atan(y/x) + pi
>>> refine_atan2(atan2(y,x), Q.zero(y) & Q.negative(x))
pi
>>> refine_atan2(atan2(y,x), Q.positive(y) & Q.zero(x))
pi/2
>>> refine_atan2(atan2(y,x), Q.negative(y) & Q.zero(x))
-pi/2
>>> refine_atan2(atan2(y,x), Q.zero(y) & Q.zero(x))
nan
"""
from sympy.functions.elementary.trigonometric import atan
y, x = expr.args
if ask(Q.real(y) & Q.positive(x), assumptions):
return atan(y / x)
elif ask(Q.negative(y) & Q.negative(x), assumptions):
return atan(y / x) - S.Pi
elif ask(Q.positive(y) & Q.negative(x), assumptions):
return atan(y / x) + S.Pi
elif ask(Q.zero(y) & Q.negative(x), assumptions):
return S.Pi
elif ask(Q.positive(y) & Q.zero(x), assumptions):
return S.Pi/2
elif ask(Q.negative(y) & Q.zero(x), assumptions):
return -S.Pi/2
elif ask(Q.zero(y) & Q.zero(x), assumptions):
return S.NaN
else:
return expr
def refine_re(expr, assumptions):
"""
Handler for real part.
Examples
========
>>> from sympy.assumptions.refine import refine_re
>>> from sympy import Q, re
>>> from sympy.abc import x
>>> refine_re(re(x), Q.real(x))
x
>>> refine_re(re(x), Q.imaginary(x))
0
"""
arg = expr.args[0]
if ask(Q.real(arg), assumptions):
return arg
if ask(Q.imaginary(arg), assumptions):
return S.Zero
return _refine_reim(expr, assumptions)
def refine_im(expr, assumptions):
"""
Handler for imaginary part.
Explanation
===========
>>> from sympy.assumptions.refine import refine_im
>>> from sympy import Q, im
>>> from sympy.abc import x
>>> refine_im(im(x), Q.real(x))
0
>>> refine_im(im(x), Q.imaginary(x))
-I*x
"""
arg = expr.args[0]
if ask(Q.real(arg), assumptions):
return S.Zero
if ask(Q.imaginary(arg), assumptions):
return - S.ImaginaryUnit * arg
return _refine_reim(expr, assumptions)
def refine_arg(expr, assumptions):
"""
Handler for complex argument
Explanation
===========
>>> from sympy.assumptions.refine import refine_arg
>>> from sympy import Q, arg
>>> from sympy.abc import x
>>> refine_arg(arg(x), Q.positive(x))
0
>>> refine_arg(arg(x), Q.negative(x))
pi
"""
rg = expr.args[0]
if ask(Q.positive(rg), assumptions):
return S.Zero
if ask(Q.negative(rg), assumptions):
return S.Pi
return None
def _refine_reim(expr, assumptions):
# Helper function for refine_re & refine_im
expanded = expr.expand(complex = True)
if expanded != expr:
refined = refine(expanded, assumptions)
if refined != expanded:
return refined
# Best to leave the expression as is
return None
def refine_sign(expr, assumptions):
"""
Handler for sign.
Examples
========
>>> from sympy.assumptions.refine import refine_sign
>>> from sympy import Symbol, Q, sign, im
>>> x = Symbol('x', real = True)
>>> expr = sign(x)
>>> refine_sign(expr, Q.positive(x) & Q.nonzero(x))
1
>>> refine_sign(expr, Q.negative(x) & Q.nonzero(x))
-1
>>> refine_sign(expr, Q.zero(x))
0
>>> y = Symbol('y', imaginary = True)
>>> expr = sign(y)
>>> refine_sign(expr, Q.positive(im(y)))
I
>>> refine_sign(expr, Q.negative(im(y)))
-I
"""
arg = expr.args[0]
if ask(Q.zero(arg), assumptions):
return S.Zero
if ask(Q.real(arg)):
if ask(Q.positive(arg), assumptions):
return S.One
if ask(Q.negative(arg), assumptions):
return S.NegativeOne
if ask(Q.imaginary(arg)):
arg_re, arg_im = arg.as_real_imag()
if ask(Q.positive(arg_im), assumptions):
return S.ImaginaryUnit
if ask(Q.negative(arg_im), assumptions):
return -S.ImaginaryUnit
return expr
def refine_matrixelement(expr, assumptions):
"""
Handler for symmetric part.
Examples
========
>>> from sympy.assumptions.refine import refine_matrixelement
>>> from sympy import MatrixSymbol, Q
>>> X = MatrixSymbol('X', 3, 3)
>>> refine_matrixelement(X[0, 1], Q.symmetric(X))
X[0, 1]
>>> refine_matrixelement(X[1, 0], Q.symmetric(X))
X[0, 1]
"""
from sympy.matrices.expressions.matexpr import MatrixElement
matrix, i, j = expr.args
if ask(Q.symmetric(matrix), assumptions):
if (i - j).could_extract_minus_sign():
return expr
return MatrixElement(matrix, j, i)
handlers_dict: dict[str, Callable[[Expr, Boolean], Expr]] = {
'Abs': refine_abs,
'Pow': refine_Pow,
'atan2': refine_atan2,
're': refine_re,
'im': refine_im,
'arg': refine_arg,
'sign': refine_sign,
'MatrixElement': refine_matrixelement
}
PK ]ZZZЭu��- �- sympy/assumptions/satask.py"""
Module to evaluate the proposition with assumptions using SAT algorithm.
"""
from sympy.core.singleton import S
from sympy.core.symbol import Symbol
from sympy.core.kind import NumberKind, UndefinedKind
from sympy.assumptions.ask_generated import get_all_known_matrix_facts, get_all_known_number_facts
from sympy.assumptions.assume import global_assumptions, AppliedPredicate
from sympy.assumptions.sathandlers import class_fact_registry
from sympy.core import oo
from sympy.logic.inference import satisfiable
from sympy.assumptions.cnf import CNF, EncodedCNF
from sympy.matrices.kind import MatrixKind
def satask(proposition, assumptions=True, context=global_assumptions,
use_known_facts=True, iterations=oo):
"""
Function to evaluate the proposition with assumptions using SAT algorithm.
This function extracts every fact relevant to the expressions composing
proposition and assumptions. For example, if a predicate containing
``Abs(x)`` is proposed, then ``Q.zero(Abs(x)) | Q.positive(Abs(x))``
will be found and passed to SAT solver because ``Q.nonnegative`` is
registered as a fact for ``Abs``.
Proposition is evaluated to ``True`` or ``False`` if the truth value can be
determined. If not, ``None`` is returned.
Parameters
==========
proposition : Any boolean expression.
Proposition which will be evaluated to boolean value.
assumptions : Any boolean expression, optional.
Local assumptions to evaluate the *proposition*.
context : AssumptionsContext, optional.
Default assumptions to evaluate the *proposition*. By default,
this is ``sympy.assumptions.global_assumptions`` variable.
use_known_facts : bool, optional.
If ``True``, facts from ``sympy.assumptions.ask_generated``
module are passed to SAT solver as well.
iterations : int, optional.
Number of times that relevant facts are recursively extracted.
Default is infinite times until no new fact is found.
Returns
=======
``True``, ``False``, or ``None``
Examples
========
>>> from sympy import Abs, Q
>>> from sympy.assumptions.satask import satask
>>> from sympy.abc import x
>>> satask(Q.zero(Abs(x)), Q.zero(x))
True
"""
props = CNF.from_prop(proposition)
_props = CNF.from_prop(~proposition)
assumptions = CNF.from_prop(assumptions)
context_cnf = CNF()
if context:
context_cnf = context_cnf.extend(context)
sat = get_all_relevant_facts(props, assumptions, context_cnf,
use_known_facts=use_known_facts, iterations=iterations)
sat.add_from_cnf(assumptions)
if context:
sat.add_from_cnf(context_cnf)
return check_satisfiability(props, _props, sat)
def check_satisfiability(prop, _prop, factbase):
sat_true = factbase.copy()
sat_false = factbase.copy()
sat_true.add_from_cnf(prop)
sat_false.add_from_cnf(_prop)
can_be_true = satisfiable(sat_true)
can_be_false = satisfiable(sat_false)
if can_be_true and can_be_false:
return None
if can_be_true and not can_be_false:
return True
if not can_be_true and can_be_false:
return False
if not can_be_true and not can_be_false:
# TODO: Run additional checks to see which combination of the
# assumptions, global_assumptions, and relevant_facts are
# inconsistent.
raise ValueError("Inconsistent assumptions")
def extract_predargs(proposition, assumptions=None, context=None):
"""
Extract every expression in the argument of predicates from *proposition*,
*assumptions* and *context*.
Parameters
==========
proposition : sympy.assumptions.cnf.CNF
assumptions : sympy.assumptions.cnf.CNF, optional.
context : sympy.assumptions.cnf.CNF, optional.
CNF generated from assumptions context.
Examples
========
>>> from sympy import Q, Abs
>>> from sympy.assumptions.cnf import CNF
>>> from sympy.assumptions.satask import extract_predargs
>>> from sympy.abc import x, y
>>> props = CNF.from_prop(Q.zero(Abs(x*y)))
>>> assump = CNF.from_prop(Q.zero(x) & Q.zero(y))
>>> extract_predargs(props, assump)
{x, y, Abs(x*y)}
"""
req_keys = find_symbols(proposition)
keys = proposition.all_predicates()
# XXX: We need this since True/False are not Basic
lkeys = set()
if assumptions:
lkeys |= assumptions.all_predicates()
if context:
lkeys |= context.all_predicates()
lkeys = lkeys - {S.true, S.false}
tmp_keys = None
while tmp_keys != set():
tmp = set()
for l in lkeys:
syms = find_symbols(l)
if (syms & req_keys) != set():
tmp |= syms
tmp_keys = tmp - req_keys
req_keys |= tmp_keys
keys |= {l for l in lkeys if find_symbols(l) & req_keys != set()}
exprs = set()
for key in keys:
if isinstance(key, AppliedPredicate):
exprs |= set(key.arguments)
else:
exprs.add(key)
return exprs
def find_symbols(pred):
"""
Find every :obj:`~.Symbol` in *pred*.
Parameters
==========
pred : sympy.assumptions.cnf.CNF, or any Expr.
"""
if isinstance(pred, CNF):
symbols = set()
for a in pred.all_predicates():
symbols |= find_symbols(a)
return symbols
return pred.atoms(Symbol)
def get_relevant_clsfacts(exprs, relevant_facts=None):
"""
Extract relevant facts from the items in *exprs*. Facts are defined in
``assumptions.sathandlers`` module.
This function is recursively called by ``get_all_relevant_facts()``.
Parameters
==========
exprs : set
Expressions whose relevant facts are searched.
relevant_facts : sympy.assumptions.cnf.CNF, optional.
Pre-discovered relevant facts.
Returns
=======
exprs : set
Candidates for next relevant fact searching.
relevant_facts : sympy.assumptions.cnf.CNF
Updated relevant facts.
Examples
========
Here, we will see how facts relevant to ``Abs(x*y)`` are recursively
extracted. On the first run, set containing the expression is passed
without pre-discovered relevant facts. The result is a set containing
candidates for next run, and ``CNF()`` instance containing facts
which are relevant to ``Abs`` and its argument.
>>> from sympy import Abs
>>> from sympy.assumptions.satask import get_relevant_clsfacts
>>> from sympy.abc import x, y
>>> exprs = {Abs(x*y)}
>>> exprs, facts = get_relevant_clsfacts(exprs)
>>> exprs
{x*y}
>>> facts.clauses #doctest: +SKIP
{frozenset({Literal(Q.odd(Abs(x*y)), False), Literal(Q.odd(x*y), True)}),
frozenset({Literal(Q.zero(Abs(x*y)), False), Literal(Q.zero(x*y), True)}),
frozenset({Literal(Q.even(Abs(x*y)), False), Literal(Q.even(x*y), True)}),
frozenset({Literal(Q.zero(Abs(x*y)), True), Literal(Q.zero(x*y), False)}),
frozenset({Literal(Q.even(Abs(x*y)), False),
Literal(Q.odd(Abs(x*y)), False),
Literal(Q.odd(x*y), True)}),
frozenset({Literal(Q.even(Abs(x*y)), False),
Literal(Q.even(x*y), True),
Literal(Q.odd(Abs(x*y)), False)}),
frozenset({Literal(Q.positive(Abs(x*y)), False),
Literal(Q.zero(Abs(x*y)), False)})}
We pass the first run's results to the second run, and get the expressions
for next run and updated facts.
>>> exprs, facts = get_relevant_clsfacts(exprs, relevant_facts=facts)
>>> exprs
{x, y}
On final run, no more candidate is returned thus we know that all
relevant facts are successfully retrieved.
>>> exprs, facts = get_relevant_clsfacts(exprs, relevant_facts=facts)
>>> exprs
set()
"""
if not relevant_facts:
relevant_facts = CNF()
newexprs = set()
for expr in exprs:
for fact in class_fact_registry(expr):
newfact = CNF.to_CNF(fact)
relevant_facts = relevant_facts._and(newfact)
for key in newfact.all_predicates():
if isinstance(key, AppliedPredicate):
newexprs |= set(key.arguments)
return newexprs - exprs, relevant_facts
def get_all_relevant_facts(proposition, assumptions, context,
use_known_facts=True, iterations=oo):
"""
Extract all relevant facts from *proposition* and *assumptions*.
This function extracts the facts by recursively calling
``get_relevant_clsfacts()``. Extracted facts are converted to
``EncodedCNF`` and returned.
Parameters
==========
proposition : sympy.assumptions.cnf.CNF
CNF generated from proposition expression.
assumptions : sympy.assumptions.cnf.CNF
CNF generated from assumption expression.
context : sympy.assumptions.cnf.CNF
CNF generated from assumptions context.
use_known_facts : bool, optional.
If ``True``, facts from ``sympy.assumptions.ask_generated``
module are encoded as well.
iterations : int, optional.
Number of times that relevant facts are recursively extracted.
Default is infinite times until no new fact is found.
Returns
=======
sympy.assumptions.cnf.EncodedCNF
Examples
========
>>> from sympy import Q
>>> from sympy.assumptions.cnf import CNF
>>> from sympy.assumptions.satask import get_all_relevant_facts
>>> from sympy.abc import x, y
>>> props = CNF.from_prop(Q.nonzero(x*y))
>>> assump = CNF.from_prop(Q.nonzero(x))
>>> context = CNF.from_prop(Q.nonzero(y))
>>> get_all_relevant_facts(props, assump, context) #doctest: +SKIP
<sympy.assumptions.cnf.EncodedCNF at 0x7f09faa6ccd0>
"""
# The relevant facts might introduce new keys, e.g., Q.zero(x*y) will
# introduce the keys Q.zero(x) and Q.zero(y), so we need to run it until
# we stop getting new things. Hopefully this strategy won't lead to an
# infinite loop in the future.
i = 0
relevant_facts = CNF()
all_exprs = set()
while True:
if i == 0:
exprs = extract_predargs(proposition, assumptions, context)
all_exprs |= exprs
exprs, relevant_facts = get_relevant_clsfacts(exprs, relevant_facts)
i += 1
if i >= iterations:
break
if not exprs:
break
if use_known_facts:
known_facts_CNF = CNF()
if any(expr.kind == MatrixKind(NumberKind) for expr in all_exprs):
known_facts_CNF.add_clauses(get_all_known_matrix_facts())
# check for undefinedKind since kind system isn't fully implemented
if any(((expr.kind == NumberKind) or (expr.kind == UndefinedKind)) for expr in all_exprs):
known_facts_CNF.add_clauses(get_all_known_number_facts())
kf_encoded = EncodedCNF()
kf_encoded.from_cnf(known_facts_CNF)
def translate_literal(lit, delta):
if lit > 0:
return lit + delta
else:
return lit - delta
def translate_data(data, delta):
return [{translate_literal(i, delta) for i in clause} for clause in data]
data = []
symbols = []
n_lit = len(kf_encoded.symbols)
for i, expr in enumerate(all_exprs):
symbols += [pred(expr) for pred in kf_encoded.symbols]
data += translate_data(kf_encoded.data, i * n_lit)
encoding = dict(list(zip(symbols, range(1, len(symbols)+1))))
ctx = EncodedCNF(data, encoding)
else:
ctx = EncodedCNF()
ctx.add_from_cnf(relevant_facts)
return ctx
PK ]ZZZ�9���$ �$ sympy/assumptions/sathandlers.pyfrom collections import defaultdict
from sympy.assumptions.ask import Q
from sympy.core import (Add, Mul, Pow, Number, NumberSymbol, Symbol)
from sympy.core.numbers import ImaginaryUnit
from sympy.functions.elementary.complexes import Abs
from sympy.logic.boolalg import (Equivalent, And, Or, Implies)
from sympy.matrices.expressions import MatMul
# APIs here may be subject to change
### Helper functions ###
def allargs(symbol, fact, expr):
"""
Apply all arguments of the expression to the fact structure.
Parameters
==========
symbol : Symbol
A placeholder symbol.
fact : Boolean
Resulting ``Boolean`` expression.
expr : Expr
Examples
========
>>> from sympy import Q
>>> from sympy.assumptions.sathandlers import allargs
>>> from sympy.abc import x, y
>>> allargs(x, Q.negative(x) | Q.positive(x), x*y)
(Q.negative(x) | Q.positive(x)) & (Q.negative(y) | Q.positive(y))
"""
return And(*[fact.subs(symbol, arg) for arg in expr.args])
def anyarg(symbol, fact, expr):
"""
Apply any argument of the expression to the fact structure.
Parameters
==========
symbol : Symbol
A placeholder symbol.
fact : Boolean
Resulting ``Boolean`` expression.
expr : Expr
Examples
========
>>> from sympy import Q
>>> from sympy.assumptions.sathandlers import anyarg
>>> from sympy.abc import x, y
>>> anyarg(x, Q.negative(x) & Q.positive(x), x*y)
(Q.negative(x) & Q.positive(x)) | (Q.negative(y) & Q.positive(y))
"""
return Or(*[fact.subs(symbol, arg) for arg in expr.args])
def exactlyonearg(symbol, fact, expr):
"""
Apply exactly one argument of the expression to the fact structure.
Parameters
==========
symbol : Symbol
A placeholder symbol.
fact : Boolean
Resulting ``Boolean`` expression.
expr : Expr
Examples
========
>>> from sympy import Q
>>> from sympy.assumptions.sathandlers import exactlyonearg
>>> from sympy.abc import x, y
>>> exactlyonearg(x, Q.positive(x), x*y)
(Q.positive(x) & ~Q.positive(y)) | (Q.positive(y) & ~Q.positive(x))
"""
pred_args = [fact.subs(symbol, arg) for arg in expr.args]
res = Or(*[And(pred_args[i], *[~lit for lit in pred_args[:i] +
pred_args[i+1:]]) for i in range(len(pred_args))])
return res
### Fact registry ###
class ClassFactRegistry:
"""
Register handlers against classes.
Explanation
===========
``register`` method registers the handler function for a class. Here,
handler function should return a single fact. ``multiregister`` method
registers the handler function for multiple classes. Here, handler function
should return a container of multiple facts.
``registry(expr)`` returns a set of facts for *expr*.
Examples
========
Here, we register the facts for ``Abs``.
>>> from sympy import Abs, Equivalent, Q
>>> from sympy.assumptions.sathandlers import ClassFactRegistry
>>> reg = ClassFactRegistry()
>>> @reg.register(Abs)
... def f1(expr):
... return Q.nonnegative(expr)
>>> @reg.register(Abs)
... def f2(expr):
... arg = expr.args[0]
... return Equivalent(~Q.zero(arg), ~Q.zero(expr))
Calling the registry with expression returns the defined facts for the
expression.
>>> from sympy.abc import x
>>> reg(Abs(x))
{Q.nonnegative(Abs(x)), Equivalent(~Q.zero(x), ~Q.zero(Abs(x)))}
Multiple facts can be registered at once by ``multiregister`` method.
>>> reg2 = ClassFactRegistry()
>>> @reg2.multiregister(Abs)
... def _(expr):
... arg = expr.args[0]
... return [Q.even(arg) >> Q.even(expr), Q.odd(arg) >> Q.odd(expr)]
>>> reg2(Abs(x))
{Implies(Q.even(x), Q.even(Abs(x))), Implies(Q.odd(x), Q.odd(Abs(x)))}
"""
def __init__(self):
self.singlefacts = defaultdict(frozenset)
self.multifacts = defaultdict(frozenset)
def register(self, cls):
def _(func):
self.singlefacts[cls] |= {func}
return func
return _
def multiregister(self, *classes):
def _(func):
for cls in classes:
self.multifacts[cls] |= {func}
return func
return _
def __getitem__(self, key):
ret1 = self.singlefacts[key]
for k in self.singlefacts:
if issubclass(key, k):
ret1 |= self.singlefacts[k]
ret2 = self.multifacts[key]
for k in self.multifacts:
if issubclass(key, k):
ret2 |= self.multifacts[k]
return ret1, ret2
def __call__(self, expr):
ret = set()
handlers1, handlers2 = self[type(expr)]
ret.update(h(expr) for h in handlers1)
for h in handlers2:
ret.update(h(expr))
return ret
class_fact_registry = ClassFactRegistry()
### Class fact registration ###
x = Symbol('x')
## Abs ##
@class_fact_registry.multiregister(Abs)
def _(expr):
arg = expr.args[0]
return [Q.nonnegative(expr),
Equivalent(~Q.zero(arg), ~Q.zero(expr)),
Q.even(arg) >> Q.even(expr),
Q.odd(arg) >> Q.odd(expr),
Q.integer(arg) >> Q.integer(expr),
]
### Add ##
@class_fact_registry.multiregister(Add)
def _(expr):
return [allargs(x, Q.positive(x), expr) >> Q.positive(expr),
allargs(x, Q.negative(x), expr) >> Q.negative(expr),
allargs(x, Q.real(x), expr) >> Q.real(expr),
allargs(x, Q.rational(x), expr) >> Q.rational(expr),
allargs(x, Q.integer(x), expr) >> Q.integer(expr),
exactlyonearg(x, ~Q.integer(x), expr) >> ~Q.integer(expr),
]
@class_fact_registry.register(Add)
def _(expr):
allargs_real = allargs(x, Q.real(x), expr)
onearg_irrational = exactlyonearg(x, Q.irrational(x), expr)
return Implies(allargs_real, Implies(onearg_irrational, Q.irrational(expr)))
### Mul ###
@class_fact_registry.multiregister(Mul)
def _(expr):
return [Equivalent(Q.zero(expr), anyarg(x, Q.zero(x), expr)),
allargs(x, Q.positive(x), expr) >> Q.positive(expr),
allargs(x, Q.real(x), expr) >> Q.real(expr),
allargs(x, Q.rational(x), expr) >> Q.rational(expr),
allargs(x, Q.integer(x), expr) >> Q.integer(expr),
exactlyonearg(x, ~Q.rational(x), expr) >> ~Q.integer(expr),
allargs(x, Q.commutative(x), expr) >> Q.commutative(expr),
]
@class_fact_registry.register(Mul)
def _(expr):
# Implicitly assumes Mul has more than one arg
# Would be allargs(x, Q.prime(x) | Q.composite(x)) except 1 is composite
# More advanced prime assumptions will require inequalities, as 1 provides
# a corner case.
allargs_prime = allargs(x, Q.prime(x), expr)
return Implies(allargs_prime, ~Q.prime(expr))
@class_fact_registry.register(Mul)
def _(expr):
# General Case: Odd number of imaginary args implies mul is imaginary(To be implemented)
allargs_imag_or_real = allargs(x, Q.imaginary(x) | Q.real(x), expr)
onearg_imaginary = exactlyonearg(x, Q.imaginary(x), expr)
return Implies(allargs_imag_or_real, Implies(onearg_imaginary, Q.imaginary(expr)))
@class_fact_registry.register(Mul)
def _(expr):
allargs_real = allargs(x, Q.real(x), expr)
onearg_irrational = exactlyonearg(x, Q.irrational(x), expr)
return Implies(allargs_real, Implies(onearg_irrational, Q.irrational(expr)))
@class_fact_registry.register(Mul)
def _(expr):
# Including the integer qualification means we don't need to add any facts
# for odd, since the assumptions already know that every integer is
# exactly one of even or odd.
allargs_integer = allargs(x, Q.integer(x), expr)
anyarg_even = anyarg(x, Q.even(x), expr)
return Implies(allargs_integer, Equivalent(anyarg_even, Q.even(expr)))
### MatMul ###
@class_fact_registry.register(MatMul)
def _(expr):
allargs_square = allargs(x, Q.square(x), expr)
allargs_invertible = allargs(x, Q.invertible(x), expr)
return Implies(allargs_square, Equivalent(Q.invertible(expr), allargs_invertible))
### Pow ###
@class_fact_registry.multiregister(Pow)
def _(expr):
base, exp = expr.base, expr.exp
return [
(Q.real(base) & Q.even(exp) & Q.nonnegative(exp)) >> Q.nonnegative(expr),
(Q.nonnegative(base) & Q.odd(exp) & Q.nonnegative(exp)) >> Q.nonnegative(expr),
(Q.nonpositive(base) & Q.odd(exp) & Q.nonnegative(exp)) >> Q.nonpositive(expr),
Equivalent(Q.zero(expr), Q.zero(base) & Q.positive(exp))
]
### Numbers ###
_old_assump_getters = {
Q.positive: lambda o: o.is_positive,
Q.zero: lambda o: o.is_zero,
Q.negative: lambda o: o.is_negative,
Q.rational: lambda o: o.is_rational,
Q.irrational: lambda o: o.is_irrational,
Q.even: lambda o: o.is_even,
Q.odd: lambda o: o.is_odd,
Q.imaginary: lambda o: o.is_imaginary,
Q.prime: lambda o: o.is_prime,
Q.composite: lambda o: o.is_composite,
}
@class_fact_registry.multiregister(Number, NumberSymbol, ImaginaryUnit)
def _(expr):
ret = []
for p, getter in _old_assump_getters.items():
pred = p(expr)
prop = getter(expr)
if prop is not None:
ret.append(Equivalent(pred, prop))
return ret
PK ]ZZZڕGi: : sympy/assumptions/wrapper.py"""
Functions and wrapper object to call assumption property and predicate
query with same syntax.
In SymPy, there are two assumption systems. Old assumption system is
defined in sympy/core/assumptions, and it can be accessed by attribute
such as ``x.is_even``. New assumption system is defined in
sympy/assumptions, and it can be accessed by predicates such as
``Q.even(x)``.
Old assumption is fast, while new assumptions can freely take local facts.
In general, old assumption is used in evaluation method and new assumption
is used in refinement method.
In most cases, both evaluation and refinement follow the same process, and
the only difference is which assumption system is used. This module provides
``is_[...]()`` functions and ``AssumptionsWrapper()`` class which allows
using two systems with same syntax so that parallel code implementation can be
avoided.
Examples
========
For multiple use, use ``AssumptionsWrapper()``.
>>> from sympy import Q, Symbol
>>> from sympy.assumptions.wrapper import AssumptionsWrapper
>>> x = Symbol('x')
>>> _x = AssumptionsWrapper(x, Q.even(x))
>>> _x.is_integer
True
>>> _x.is_odd
False
For single use, use ``is_[...]()`` functions.
>>> from sympy.assumptions.wrapper import is_infinite
>>> a = Symbol('a')
>>> print(is_infinite(a))
None
>>> is_infinite(a, Q.finite(a))
False
"""
from sympy.assumptions import ask, Q
from sympy.core.basic import Basic
from sympy.core.sympify import _sympify
def make_eval_method(fact):
def getit(self):
pred = getattr(Q, fact)
ret = ask(pred(self.expr), self.assumptions)
return ret
return getit
# we subclass Basic to use the fact deduction and caching
class AssumptionsWrapper(Basic):
"""
Wrapper over ``Basic`` instances to call predicate query by
``.is_[...]`` property
Parameters
==========
expr : Basic
assumptions : Boolean, optional
Examples
========
>>> from sympy import Q, Symbol
>>> from sympy.assumptions.wrapper import AssumptionsWrapper
>>> x = Symbol('x', even=True)
>>> AssumptionsWrapper(x).is_integer
True
>>> y = Symbol('y')
>>> AssumptionsWrapper(y, Q.even(y)).is_integer
True
With ``AssumptionsWrapper``, both evaluation and refinement can be supported
by single implementation.
>>> from sympy import Function
>>> class MyAbs(Function):
... @classmethod
... def eval(cls, x, assumptions=True):
... _x = AssumptionsWrapper(x, assumptions)
... if _x.is_nonnegative:
... return x
... if _x.is_negative:
... return -x
... def _eval_refine(self, assumptions):
... return MyAbs.eval(self.args[0], assumptions)
>>> MyAbs(x)
MyAbs(x)
>>> MyAbs(x).refine(Q.positive(x))
x
>>> MyAbs(Symbol('y', negative=True))
-y
"""
def __new__(cls, expr, assumptions=None):
if assumptions is None:
return expr
obj = super().__new__(cls, expr, _sympify(assumptions))
obj.expr = expr
obj.assumptions = assumptions
return obj
_eval_is_algebraic = make_eval_method("algebraic")
_eval_is_antihermitian = make_eval_method("antihermitian")
_eval_is_commutative = make_eval_method("commutative")
_eval_is_complex = make_eval_method("complex")
_eval_is_composite = make_eval_method("composite")
_eval_is_even = make_eval_method("even")
_eval_is_extended_negative = make_eval_method("extended_negative")
_eval_is_extended_nonnegative = make_eval_method("extended_nonnegative")
_eval_is_extended_nonpositive = make_eval_method("extended_nonpositive")
_eval_is_extended_nonzero = make_eval_method("extended_nonzero")
_eval_is_extended_positive = make_eval_method("extended_positive")
_eval_is_extended_real = make_eval_method("extended_real")
_eval_is_finite = make_eval_method("finite")
_eval_is_hermitian = make_eval_method("hermitian")
_eval_is_imaginary = make_eval_method("imaginary")
_eval_is_infinite = make_eval_method("infinite")
_eval_is_integer = make_eval_method("integer")
_eval_is_irrational = make_eval_method("irrational")
_eval_is_negative = make_eval_method("negative")
_eval_is_noninteger = make_eval_method("noninteger")
_eval_is_nonnegative = make_eval_method("nonnegative")
_eval_is_nonpositive = make_eval_method("nonpositive")
_eval_is_nonzero = make_eval_method("nonzero")
_eval_is_odd = make_eval_method("odd")
_eval_is_polar = make_eval_method("polar")
_eval_is_positive = make_eval_method("positive")
_eval_is_prime = make_eval_method("prime")
_eval_is_rational = make_eval_method("rational")
_eval_is_real = make_eval_method("real")
_eval_is_transcendental = make_eval_method("transcendental")
_eval_is_zero = make_eval_method("zero")
# one shot functions which are faster than AssumptionsWrapper
def is_infinite(obj, assumptions=None):
if assumptions is None:
return obj.is_infinite
return ask(Q.infinite(obj), assumptions)
def is_extended_real(obj, assumptions=None):
if assumptions is None:
return obj.is_extended_real
return ask(Q.extended_real(obj), assumptions)
def is_extended_nonnegative(obj, assumptions=None):
if assumptions is None:
return obj.is_extended_nonnegative
return ask(Q.extended_nonnegative(obj), assumptions)
PK ]ZZZ�yl�J J & sympy/assumptions/handlers/__init__.py"""
Multipledispatch handlers for ``Predicate`` are implemented here.
Handlers in this module are not directly imported to other modules in
order to avoid circular import problem.
"""
from .common import (AskHandler, CommonHandler,
test_closed_group)
__all__ = [
'AskHandler', 'CommonHandler',
'test_closed_group'
]
PK ]ZZZ���� & sympy/assumptions/handlers/calculus.py"""
This module contains query handlers responsible for calculus queries:
infinitesimal, finite, etc.
"""
from sympy.assumptions import Q, ask
from sympy.core import Add, Mul, Pow, Symbol
from sympy.core.numbers import (NegativeInfinity, GoldenRatio,
Infinity, Exp1, ComplexInfinity, ImaginaryUnit, NaN, Number, Pi, E,
TribonacciConstant)
from sympy.functions import cos, exp, log, sign, sin
from sympy.logic.boolalg import conjuncts
from ..predicates.calculus import (FinitePredicate, InfinitePredicate,
PositiveInfinitePredicate, NegativeInfinitePredicate)
# FinitePredicate
@FinitePredicate.register(Symbol)
def _(expr, assumptions):
"""
Handles Symbol.
"""
if expr.is_finite is not None:
return expr.is_finite
if Q.finite(expr) in conjuncts(assumptions):
return True
return None
@FinitePredicate.register(Add)
def _(expr, assumptions):
"""
Return True if expr is bounded, False if not and None if unknown.
Truth Table:
+-------+-----+-----------+-----------+
| | | | |
| | B | U | ? |
| | | | |
+-------+-----+---+---+---+---+---+---+
| | | | | | | | |
| | |'+'|'-'|'x'|'+'|'-'|'x'|
| | | | | | | | |
+-------+-----+---+---+---+---+---+---+
| | | | |
| B | B | U | ? |
| | | | |
+---+---+-----+---+---+---+---+---+---+
| | | | | | | | | |
| |'+'| | U | ? | ? | U | ? | ? |
| | | | | | | | | |
| +---+-----+---+---+---+---+---+---+
| | | | | | | | | |
| U |'-'| | ? | U | ? | ? | U | ? |
| | | | | | | | | |
| +---+-----+---+---+---+---+---+---+
| | | | | |
| |'x'| | ? | ? |
| | | | | |
+---+---+-----+---+---+---+---+---+---+
| | | | |
| ? | | | ? |
| | | | |
+-------+-----+-----------+---+---+---+
* 'B' = Bounded
* 'U' = Unbounded
* '?' = unknown boundedness
* '+' = positive sign
* '-' = negative sign
* 'x' = sign unknown
* All Bounded -> True
* 1 Unbounded and the rest Bounded -> False
* >1 Unbounded, all with same known sign -> False
* Any Unknown and unknown sign -> None
* Else -> None
When the signs are not the same you can have an undefined
result as in oo - oo, hence 'bounded' is also undefined.
"""
sign = -1 # sign of unknown or infinite
result = True
for arg in expr.args:
_bounded = ask(Q.finite(arg), assumptions)
if _bounded:
continue
s = ask(Q.extended_positive(arg), assumptions)
# if there has been more than one sign or if the sign of this arg
# is None and Bounded is None or there was already
# an unknown sign, return None
if sign != -1 and s != sign or \
s is None and None in (_bounded, sign):
return None
else:
sign = s
# once False, do not change
if result is not False:
result = _bounded
return result
@FinitePredicate.register(Mul)
def _(expr, assumptions):
"""
Return True if expr is bounded, False if not and None if unknown.
Truth Table:
+---+---+---+--------+
| | | | |
| | B | U | ? |
| | | | |
+---+---+---+---+----+
| | | | | |
| | | | s | /s |
| | | | | |
+---+---+---+---+----+
| | | | |
| B | B | U | ? |
| | | | |
+---+---+---+---+----+
| | | | | |
| U | | U | U | ? |
| | | | | |
+---+---+---+---+----+
| | | | |
| ? | | | ? |
| | | | |
+---+---+---+---+----+
* B = Bounded
* U = Unbounded
* ? = unknown boundedness
* s = signed (hence nonzero)
* /s = not signed
"""
result = True
for arg in expr.args:
_bounded = ask(Q.finite(arg), assumptions)
if _bounded:
continue
elif _bounded is None:
if result is None:
return None
if ask(Q.extended_nonzero(arg), assumptions) is None:
return None
if result is not False:
result = None
else:
result = False
return result
@FinitePredicate.register(Pow)
def _(expr, assumptions):
"""
* Unbounded ** NonZero -> Unbounded
* Bounded ** Bounded -> Bounded
* Abs()<=1 ** Positive -> Bounded
* Abs()>=1 ** Negative -> Bounded
* Otherwise unknown
"""
if expr.base == E:
return ask(Q.finite(expr.exp), assumptions)
base_bounded = ask(Q.finite(expr.base), assumptions)
exp_bounded = ask(Q.finite(expr.exp), assumptions)
if base_bounded is None and exp_bounded is None: # Common Case
return None
if base_bounded is False and ask(Q.extended_nonzero(expr.exp), assumptions):
return False
if base_bounded and exp_bounded:
return True
if (abs(expr.base) <= 1) == True and ask(Q.extended_positive(expr.exp), assumptions):
return True
if (abs(expr.base) >= 1) == True and ask(Q.extended_negative(expr.exp), assumptions):
return True
if (abs(expr.base) >= 1) == True and exp_bounded is False:
return False
return None
@FinitePredicate.register(exp)
def _(expr, assumptions):
return ask(Q.finite(expr.exp), assumptions)
@FinitePredicate.register(log)
def _(expr, assumptions):
# After complex -> finite fact is registered to new assumption system,
# querying Q.infinite may be removed.
if ask(Q.infinite(expr.args[0]), assumptions):
return False
return ask(~Q.zero(expr.args[0]), assumptions)
@FinitePredicate.register_many(cos, sin, Number, Pi, Exp1, GoldenRatio,
TribonacciConstant, ImaginaryUnit, sign)
def _(expr, assumptions):
return True
@FinitePredicate.register_many(ComplexInfinity, Infinity, NegativeInfinity)
def _(expr, assumptions):
return False
@FinitePredicate.register(NaN)
def _(expr, assumptions):
return None
# InfinitePredicate
@InfinitePredicate.register_many(ComplexInfinity, Infinity, NegativeInfinity)
def _(expr, assumptions):
return True
# PositiveInfinitePredicate
@PositiveInfinitePredicate.register(Infinity)
def _(expr, assumptions):
return True
@PositiveInfinitePredicate.register_many(NegativeInfinity, ComplexInfinity)
def _(expr, assumptions):
return False
# NegativeInfinitePredicate
@NegativeInfinitePredicate.register(NegativeInfinity)
def _(expr, assumptions):
return True
@NegativeInfinitePredicate.register_many(Infinity, ComplexInfinity)
def _(expr, assumptions):
return False
PK ]ZZZQ,=�� � $ sympy/assumptions/handlers/common.py"""
This module defines base class for handlers and some core handlers:
``Q.commutative`` and ``Q.is_true``.
"""
from sympy.assumptions import Q, ask, AppliedPredicate
from sympy.core import Basic, Symbol
from sympy.core.logic import _fuzzy_group
from sympy.core.numbers import NaN, Number
from sympy.logic.boolalg import (And, BooleanTrue, BooleanFalse, conjuncts,
Equivalent, Implies, Not, Or)
from sympy.utilities.exceptions import sympy_deprecation_warning
from ..predicates.common import CommutativePredicate, IsTruePredicate
class AskHandler:
"""Base class that all Ask Handlers must inherit."""
def __new__(cls, *args, **kwargs):
sympy_deprecation_warning(
"""
The AskHandler system is deprecated. The AskHandler class should
be replaced with the multipledispatch handler of Predicate
""",
deprecated_since_version="1.8",
active_deprecations_target='deprecated-askhandler',
)
return super().__new__(cls, *args, **kwargs)
class CommonHandler(AskHandler):
# Deprecated
"""Defines some useful methods common to most Handlers. """
@staticmethod
def AlwaysTrue(expr, assumptions):
return True
@staticmethod
def AlwaysFalse(expr, assumptions):
return False
@staticmethod
def AlwaysNone(expr, assumptions):
return None
NaN = AlwaysFalse
# CommutativePredicate
@CommutativePredicate.register(Symbol)
def _(expr, assumptions):
"""Objects are expected to be commutative unless otherwise stated"""
assumps = conjuncts(assumptions)
if expr.is_commutative is not None:
return expr.is_commutative and not ~Q.commutative(expr) in assumps
if Q.commutative(expr) in assumps:
return True
elif ~Q.commutative(expr) in assumps:
return False
return True
@CommutativePredicate.register(Basic)
def _(expr, assumptions):
for arg in expr.args:
if not ask(Q.commutative(arg), assumptions):
return False
return True
@CommutativePredicate.register(Number)
def _(expr, assumptions):
return True
@CommutativePredicate.register(NaN)
def _(expr, assumptions):
return True
# IsTruePredicate
@IsTruePredicate.register(bool)
def _(expr, assumptions):
return expr
@IsTruePredicate.register(BooleanTrue)
def _(expr, assumptions):
return True
@IsTruePredicate.register(BooleanFalse)
def _(expr, assumptions):
return False
@IsTruePredicate.register(AppliedPredicate)
def _(expr, assumptions):
return ask(expr, assumptions)
@IsTruePredicate.register(Not)
def _(expr, assumptions):
arg = expr.args[0]
if arg.is_Symbol:
# symbol used as abstract boolean object
return None
value = ask(arg, assumptions=assumptions)
if value in (True, False):
return not value
else:
return None
@IsTruePredicate.register(Or)
def _(expr, assumptions):
result = False
for arg in expr.args:
p = ask(arg, assumptions=assumptions)
if p is True:
return True
if p is None:
result = None
return result
@IsTruePredicate.register(And)
def _(expr, assumptions):
result = True
for arg in expr.args:
p = ask(arg, assumptions=assumptions)
if p is False:
return False
if p is None:
result = None
return result
@IsTruePredicate.register(Implies)
def _(expr, assumptions):
p, q = expr.args
return ask(~p | q, assumptions=assumptions)
@IsTruePredicate.register(Equivalent)
def _(expr, assumptions):
p, q = expr.args
pt = ask(p, assumptions=assumptions)
if pt is None:
return None
qt = ask(q, assumptions=assumptions)
if qt is None:
return None
return pt == qt
#### Helper methods
def test_closed_group(expr, assumptions, key):
"""
Test for membership in a group with respect
to the current operation.
"""
return _fuzzy_group(
(ask(key(a), assumptions) for a in expr.args), quick_exit=True)
PK ]ZZZK��1W 1W & sympy/assumptions/handlers/matrices.py"""
This module contains query handlers responsible for Matrices queries:
Square, Symmetric, Invertible etc.
"""
from sympy.logic.boolalg import conjuncts
from sympy.assumptions import Q, ask
from sympy.assumptions.handlers import test_closed_group
from sympy.matrices import MatrixBase
from sympy.matrices.expressions import (BlockMatrix, BlockDiagMatrix, Determinant,
DiagMatrix, DiagonalMatrix, HadamardProduct, Identity, Inverse, MatAdd, MatMul,
MatPow, MatrixExpr, MatrixSlice, MatrixSymbol, OneMatrix, Trace, Transpose,
ZeroMatrix)
from sympy.matrices.expressions.blockmatrix import reblock_2x2
from sympy.matrices.expressions.factorizations import Factorization
from sympy.matrices.expressions.fourier import DFT
from sympy.core.logic import fuzzy_and
from sympy.utilities.iterables import sift
from sympy.core import Basic
from ..predicates.matrices import (SquarePredicate, SymmetricPredicate,
InvertiblePredicate, OrthogonalPredicate, UnitaryPredicate,
FullRankPredicate, PositiveDefinitePredicate, UpperTriangularPredicate,
LowerTriangularPredicate, DiagonalPredicate, IntegerElementsPredicate,
RealElementsPredicate, ComplexElementsPredicate)
def _Factorization(predicate, expr, assumptions):
if predicate in expr.predicates:
return True
# SquarePredicate
@SquarePredicate.register(MatrixExpr)
def _(expr, assumptions):
return expr.shape[0] == expr.shape[1]
# SymmetricPredicate
@SymmetricPredicate.register(MatMul)
def _(expr, assumptions):
factor, mmul = expr.as_coeff_mmul()
if all(ask(Q.symmetric(arg), assumptions) for arg in mmul.args):
return True
# TODO: implement sathandlers system for the matrices.
# Now it duplicates the general fact: Implies(Q.diagonal, Q.symmetric).
if ask(Q.diagonal(expr), assumptions):
return True
if len(mmul.args) >= 2 and mmul.args[0] == mmul.args[-1].T:
if len(mmul.args) == 2:
return True
return ask(Q.symmetric(MatMul(*mmul.args[1:-1])), assumptions)
@SymmetricPredicate.register(MatPow)
def _(expr, assumptions):
# only for integer powers
base, exp = expr.args
int_exp = ask(Q.integer(exp), assumptions)
if not int_exp:
return None
non_negative = ask(~Q.negative(exp), assumptions)
if (non_negative or non_negative == False
and ask(Q.invertible(base), assumptions)):
return ask(Q.symmetric(base), assumptions)
return None
@SymmetricPredicate.register(MatAdd)
def _(expr, assumptions):
return all(ask(Q.symmetric(arg), assumptions) for arg in expr.args)
@SymmetricPredicate.register(MatrixSymbol)
def _(expr, assumptions):
if not expr.is_square:
return False
# TODO: implement sathandlers system for the matrices.
# Now it duplicates the general fact: Implies(Q.diagonal, Q.symmetric).
if ask(Q.diagonal(expr), assumptions):
return True
if Q.symmetric(expr) in conjuncts(assumptions):
return True
@SymmetricPredicate.register_many(OneMatrix, ZeroMatrix)
def _(expr, assumptions):
return ask(Q.square(expr), assumptions)
@SymmetricPredicate.register_many(Inverse, Transpose)
def _(expr, assumptions):
return ask(Q.symmetric(expr.arg), assumptions)
@SymmetricPredicate.register(MatrixSlice)
def _(expr, assumptions):
# TODO: implement sathandlers system for the matrices.
# Now it duplicates the general fact: Implies(Q.diagonal, Q.symmetric).
if ask(Q.diagonal(expr), assumptions):
return True
if not expr.on_diag:
return None
else:
return ask(Q.symmetric(expr.parent), assumptions)
@SymmetricPredicate.register(Identity)
def _(expr, assumptions):
return True
# InvertiblePredicate
@InvertiblePredicate.register(MatMul)
def _(expr, assumptions):
factor, mmul = expr.as_coeff_mmul()
if all(ask(Q.invertible(arg), assumptions) for arg in mmul.args):
return True
if any(ask(Q.invertible(arg), assumptions) is False
for arg in mmul.args):
return False
@InvertiblePredicate.register(MatPow)
def _(expr, assumptions):
# only for integer powers
base, exp = expr.args
int_exp = ask(Q.integer(exp), assumptions)
if not int_exp:
return None
if exp.is_negative == False:
return ask(Q.invertible(base), assumptions)
return None
@InvertiblePredicate.register(MatAdd)
def _(expr, assumptions):
return None
@InvertiblePredicate.register(MatrixSymbol)
def _(expr, assumptions):
if not expr.is_square:
return False
if Q.invertible(expr) in conjuncts(assumptions):
return True
@InvertiblePredicate.register_many(Identity, Inverse)
def _(expr, assumptions):
return True
@InvertiblePredicate.register(ZeroMatrix)
def _(expr, assumptions):
return False
@InvertiblePredicate.register(OneMatrix)
def _(expr, assumptions):
return expr.shape[0] == 1 and expr.shape[1] == 1
@InvertiblePredicate.register(Transpose)
def _(expr, assumptions):
return ask(Q.invertible(expr.arg), assumptions)
@InvertiblePredicate.register(MatrixSlice)
def _(expr, assumptions):
if not expr.on_diag:
return None
else:
return ask(Q.invertible(expr.parent), assumptions)
@InvertiblePredicate.register(MatrixBase)
def _(expr, assumptions):
if not expr.is_square:
return False
return expr.rank() == expr.rows
@InvertiblePredicate.register(MatrixExpr)
def _(expr, assumptions):
if not expr.is_square:
return False
return None
@InvertiblePredicate.register(BlockMatrix)
def _(expr, assumptions):
if not expr.is_square:
return False
if expr.blockshape == (1, 1):
return ask(Q.invertible(expr.blocks[0, 0]), assumptions)
expr = reblock_2x2(expr)
if expr.blockshape == (2, 2):
[[A, B], [C, D]] = expr.blocks.tolist()
if ask(Q.invertible(A), assumptions) == True:
invertible = ask(Q.invertible(D - C * A.I * B), assumptions)
if invertible is not None:
return invertible
if ask(Q.invertible(B), assumptions) == True:
invertible = ask(Q.invertible(C - D * B.I * A), assumptions)
if invertible is not None:
return invertible
if ask(Q.invertible(C), assumptions) == True:
invertible = ask(Q.invertible(B - A * C.I * D), assumptions)
if invertible is not None:
return invertible
if ask(Q.invertible(D), assumptions) == True:
invertible = ask(Q.invertible(A - B * D.I * C), assumptions)
if invertible is not None:
return invertible
return None
@InvertiblePredicate.register(BlockDiagMatrix)
def _(expr, assumptions):
if expr.rowblocksizes != expr.colblocksizes:
return None
return fuzzy_and([ask(Q.invertible(a), assumptions) for a in expr.diag])
# OrthogonalPredicate
@OrthogonalPredicate.register(MatMul)
def _(expr, assumptions):
factor, mmul = expr.as_coeff_mmul()
if (all(ask(Q.orthogonal(arg), assumptions) for arg in mmul.args) and
factor == 1):
return True
if any(ask(Q.invertible(arg), assumptions) is False
for arg in mmul.args):
return False
@OrthogonalPredicate.register(MatPow)
def _(expr, assumptions):
# only for integer powers
base, exp = expr.args
int_exp = ask(Q.integer(exp), assumptions)
if int_exp:
return ask(Q.orthogonal(base), assumptions)
return None
@OrthogonalPredicate.register(MatAdd)
def _(expr, assumptions):
if (len(expr.args) == 1 and
ask(Q.orthogonal(expr.args[0]), assumptions)):
return True
@OrthogonalPredicate.register(MatrixSymbol)
def _(expr, assumptions):
if (not expr.is_square or
ask(Q.invertible(expr), assumptions) is False):
return False
if Q.orthogonal(expr) in conjuncts(assumptions):
return True
@OrthogonalPredicate.register(Identity)
def _(expr, assumptions):
return True
@OrthogonalPredicate.register(ZeroMatrix)
def _(expr, assumptions):
return False
@OrthogonalPredicate.register_many(Inverse, Transpose)
def _(expr, assumptions):
return ask(Q.orthogonal(expr.arg), assumptions)
@OrthogonalPredicate.register(MatrixSlice)
def _(expr, assumptions):
if not expr.on_diag:
return None
else:
return ask(Q.orthogonal(expr.parent), assumptions)
@OrthogonalPredicate.register(Factorization)
def _(expr, assumptions):
return _Factorization(Q.orthogonal, expr, assumptions)
# UnitaryPredicate
@UnitaryPredicate.register(MatMul)
def _(expr, assumptions):
factor, mmul = expr.as_coeff_mmul()
if (all(ask(Q.unitary(arg), assumptions) for arg in mmul.args) and
abs(factor) == 1):
return True
if any(ask(Q.invertible(arg), assumptions) is False
for arg in mmul.args):
return False
@UnitaryPredicate.register(MatPow)
def _(expr, assumptions):
# only for integer powers
base, exp = expr.args
int_exp = ask(Q.integer(exp), assumptions)
if int_exp:
return ask(Q.unitary(base), assumptions)
return None
@UnitaryPredicate.register(MatrixSymbol)
def _(expr, assumptions):
if (not expr.is_square or
ask(Q.invertible(expr), assumptions) is False):
return False
if Q.unitary(expr) in conjuncts(assumptions):
return True
@UnitaryPredicate.register_many(Inverse, Transpose)
def _(expr, assumptions):
return ask(Q.unitary(expr.arg), assumptions)
@UnitaryPredicate.register(MatrixSlice)
def _(expr, assumptions):
if not expr.on_diag:
return None
else:
return ask(Q.unitary(expr.parent), assumptions)
@UnitaryPredicate.register_many(DFT, Identity)
def _(expr, assumptions):
return True
@UnitaryPredicate.register(ZeroMatrix)
def _(expr, assumptions):
return False
@UnitaryPredicate.register(Factorization)
def _(expr, assumptions):
return _Factorization(Q.unitary, expr, assumptions)
# FullRankPredicate
@FullRankPredicate.register(MatMul)
def _(expr, assumptions):
if all(ask(Q.fullrank(arg), assumptions) for arg in expr.args):
return True
@FullRankPredicate.register(MatPow)
def _(expr, assumptions):
# only for integer powers
base, exp = expr.args
int_exp = ask(Q.integer(exp), assumptions)
if int_exp and ask(~Q.negative(exp), assumptions):
return ask(Q.fullrank(base), assumptions)
return None
@FullRankPredicate.register(Identity)
def _(expr, assumptions):
return True
@FullRankPredicate.register(ZeroMatrix)
def _(expr, assumptions):
return False
@FullRankPredicate.register(OneMatrix)
def _(expr, assumptions):
return expr.shape[0] == 1 and expr.shape[1] == 1
@FullRankPredicate.register_many(Inverse, Transpose)
def _(expr, assumptions):
return ask(Q.fullrank(expr.arg), assumptions)
@FullRankPredicate.register(MatrixSlice)
def _(expr, assumptions):
if ask(Q.orthogonal(expr.parent), assumptions):
return True
# PositiveDefinitePredicate
@PositiveDefinitePredicate.register(MatMul)
def _(expr, assumptions):
factor, mmul = expr.as_coeff_mmul()
if (all(ask(Q.positive_definite(arg), assumptions)
for arg in mmul.args) and factor > 0):
return True
if (len(mmul.args) >= 2
and mmul.args[0] == mmul.args[-1].T
and ask(Q.fullrank(mmul.args[0]), assumptions)):
return ask(Q.positive_definite(
MatMul(*mmul.args[1:-1])), assumptions)
@PositiveDefinitePredicate.register(MatPow)
def _(expr, assumptions):
# a power of a positive definite matrix is positive definite
if ask(Q.positive_definite(expr.args[0]), assumptions):
return True
@PositiveDefinitePredicate.register(MatAdd)
def _(expr, assumptions):
if all(ask(Q.positive_definite(arg), assumptions)
for arg in expr.args):
return True
@PositiveDefinitePredicate.register(MatrixSymbol)
def _(expr, assumptions):
if not expr.is_square:
return False
if Q.positive_definite(expr) in conjuncts(assumptions):
return True
@PositiveDefinitePredicate.register(Identity)
def _(expr, assumptions):
return True
@PositiveDefinitePredicate.register(ZeroMatrix)
def _(expr, assumptions):
return False
@PositiveDefinitePredicate.register(OneMatrix)
def _(expr, assumptions):
return expr.shape[0] == 1 and expr.shape[1] == 1
@PositiveDefinitePredicate.register_many(Inverse, Transpose)
def _(expr, assumptions):
return ask(Q.positive_definite(expr.arg), assumptions)
@PositiveDefinitePredicate.register(MatrixSlice)
def _(expr, assumptions):
if not expr.on_diag:
return None
else:
return ask(Q.positive_definite(expr.parent), assumptions)
# UpperTriangularPredicate
@UpperTriangularPredicate.register(MatMul)
def _(expr, assumptions):
factor, matrices = expr.as_coeff_matrices()
if all(ask(Q.upper_triangular(m), assumptions) for m in matrices):
return True
@UpperTriangularPredicate.register(MatAdd)
def _(expr, assumptions):
if all(ask(Q.upper_triangular(arg), assumptions) for arg in expr.args):
return True
@UpperTriangularPredicate.register(MatPow)
def _(expr, assumptions):
# only for integer powers
base, exp = expr.args
int_exp = ask(Q.integer(exp), assumptions)
if not int_exp:
return None
non_negative = ask(~Q.negative(exp), assumptions)
if (non_negative or non_negative == False
and ask(Q.invertible(base), assumptions)):
return ask(Q.upper_triangular(base), assumptions)
return None
@UpperTriangularPredicate.register(MatrixSymbol)
def _(expr, assumptions):
if Q.upper_triangular(expr) in conjuncts(assumptions):
return True
@UpperTriangularPredicate.register_many(Identity, ZeroMatrix)
def _(expr, assumptions):
return True
@UpperTriangularPredicate.register(OneMatrix)
def _(expr, assumptions):
return expr.shape[0] == 1 and expr.shape[1] == 1
@UpperTriangularPredicate.register(Transpose)
def _(expr, assumptions):
return ask(Q.lower_triangular(expr.arg), assumptions)
@UpperTriangularPredicate.register(Inverse)
def _(expr, assumptions):
return ask(Q.upper_triangular(expr.arg), assumptions)
@UpperTriangularPredicate.register(MatrixSlice)
def _(expr, assumptions):
if not expr.on_diag:
return None
else:
return ask(Q.upper_triangular(expr.parent), assumptions)
@UpperTriangularPredicate.register(Factorization)
def _(expr, assumptions):
return _Factorization(Q.upper_triangular, expr, assumptions)
# LowerTriangularPredicate
@LowerTriangularPredicate.register(MatMul)
def _(expr, assumptions):
factor, matrices = expr.as_coeff_matrices()
if all(ask(Q.lower_triangular(m), assumptions) for m in matrices):
return True
@LowerTriangularPredicate.register(MatAdd)
def _(expr, assumptions):
if all(ask(Q.lower_triangular(arg), assumptions) for arg in expr.args):
return True
@LowerTriangularPredicate.register(MatPow)
def _(expr, assumptions):
# only for integer powers
base, exp = expr.args
int_exp = ask(Q.integer(exp), assumptions)
if not int_exp:
return None
non_negative = ask(~Q.negative(exp), assumptions)
if (non_negative or non_negative == False
and ask(Q.invertible(base), assumptions)):
return ask(Q.lower_triangular(base), assumptions)
return None
@LowerTriangularPredicate.register(MatrixSymbol)
def _(expr, assumptions):
if Q.lower_triangular(expr) in conjuncts(assumptions):
return True
@LowerTriangularPredicate.register_many(Identity, ZeroMatrix)
def _(expr, assumptions):
return True
@LowerTriangularPredicate.register(OneMatrix)
def _(expr, assumptions):
return expr.shape[0] == 1 and expr.shape[1] == 1
@LowerTriangularPredicate.register(Transpose)
def _(expr, assumptions):
return ask(Q.upper_triangular(expr.arg), assumptions)
@LowerTriangularPredicate.register(Inverse)
def _(expr, assumptions):
return ask(Q.lower_triangular(expr.arg), assumptions)
@LowerTriangularPredicate.register(MatrixSlice)
def _(expr, assumptions):
if not expr.on_diag:
return None
else:
return ask(Q.lower_triangular(expr.parent), assumptions)
@LowerTriangularPredicate.register(Factorization)
def _(expr, assumptions):
return _Factorization(Q.lower_triangular, expr, assumptions)
# DiagonalPredicate
def _is_empty_or_1x1(expr):
return expr.shape in ((0, 0), (1, 1))
@DiagonalPredicate.register(MatMul)
def _(expr, assumptions):
if _is_empty_or_1x1(expr):
return True
factor, matrices = expr.as_coeff_matrices()
if all(ask(Q.diagonal(m), assumptions) for m in matrices):
return True
@DiagonalPredicate.register(MatPow)
def _(expr, assumptions):
# only for integer powers
base, exp = expr.args
int_exp = ask(Q.integer(exp), assumptions)
if not int_exp:
return None
non_negative = ask(~Q.negative(exp), assumptions)
if (non_negative or non_negative == False
and ask(Q.invertible(base), assumptions)):
return ask(Q.diagonal(base), assumptions)
return None
@DiagonalPredicate.register(MatAdd)
def _(expr, assumptions):
if all(ask(Q.diagonal(arg), assumptions) for arg in expr.args):
return True
@DiagonalPredicate.register(MatrixSymbol)
def _(expr, assumptions):
if _is_empty_or_1x1(expr):
return True
if Q.diagonal(expr) in conjuncts(assumptions):
return True
@DiagonalPredicate.register(OneMatrix)
def _(expr, assumptions):
return expr.shape[0] == 1 and expr.shape[1] == 1
@DiagonalPredicate.register_many(Inverse, Transpose)
def _(expr, assumptions):
return ask(Q.diagonal(expr.arg), assumptions)
@DiagonalPredicate.register(MatrixSlice)
def _(expr, assumptions):
if _is_empty_or_1x1(expr):
return True
if not expr.on_diag:
return None
else:
return ask(Q.diagonal(expr.parent), assumptions)
@DiagonalPredicate.register_many(DiagonalMatrix, DiagMatrix, Identity, ZeroMatrix)
def _(expr, assumptions):
return True
@DiagonalPredicate.register(Factorization)
def _(expr, assumptions):
return _Factorization(Q.diagonal, expr, assumptions)
# IntegerElementsPredicate
def BM_elements(predicate, expr, assumptions):
""" Block Matrix elements. """
return all(ask(predicate(b), assumptions) for b in expr.blocks)
def MS_elements(predicate, expr, assumptions):
""" Matrix Slice elements. """
return ask(predicate(expr.parent), assumptions)
def MatMul_elements(matrix_predicate, scalar_predicate, expr, assumptions):
d = sift(expr.args, lambda x: isinstance(x, MatrixExpr))
factors, matrices = d[False], d[True]
return fuzzy_and([
test_closed_group(Basic(*factors), assumptions, scalar_predicate),
test_closed_group(Basic(*matrices), assumptions, matrix_predicate)])
@IntegerElementsPredicate.register_many(Determinant, HadamardProduct, MatAdd,
Trace, Transpose)
def _(expr, assumptions):
return test_closed_group(expr, assumptions, Q.integer_elements)
@IntegerElementsPredicate.register(MatPow)
def _(expr, assumptions):
# only for integer powers
base, exp = expr.args
int_exp = ask(Q.integer(exp), assumptions)
if not int_exp:
return None
if exp.is_negative == False:
return ask(Q.integer_elements(base), assumptions)
return None
@IntegerElementsPredicate.register_many(Identity, OneMatrix, ZeroMatrix)
def _(expr, assumptions):
return True
@IntegerElementsPredicate.register(MatMul)
def _(expr, assumptions):
return MatMul_elements(Q.integer_elements, Q.integer, expr, assumptions)
@IntegerElementsPredicate.register(MatrixSlice)
def _(expr, assumptions):
return MS_elements(Q.integer_elements, expr, assumptions)
@IntegerElementsPredicate.register(BlockMatrix)
def _(expr, assumptions):
return BM_elements(Q.integer_elements, expr, assumptions)
# RealElementsPredicate
@RealElementsPredicate.register_many(Determinant, Factorization, HadamardProduct,
MatAdd, Trace, Transpose)
def _(expr, assumptions):
return test_closed_group(expr, assumptions, Q.real_elements)
@RealElementsPredicate.register(MatPow)
def _(expr, assumptions):
# only for integer powers
base, exp = expr.args
int_exp = ask(Q.integer(exp), assumptions)
if not int_exp:
return None
non_negative = ask(~Q.negative(exp), assumptions)
if (non_negative or non_negative == False
and ask(Q.invertible(base), assumptions)):
return ask(Q.real_elements(base), assumptions)
return None
@RealElementsPredicate.register(MatMul)
def _(expr, assumptions):
return MatMul_elements(Q.real_elements, Q.real, expr, assumptions)
@RealElementsPredicate.register(MatrixSlice)
def _(expr, assumptions):
return MS_elements(Q.real_elements, expr, assumptions)
@RealElementsPredicate.register(BlockMatrix)
def _(expr, assumptions):
return BM_elements(Q.real_elements, expr, assumptions)
# ComplexElementsPredicate
@ComplexElementsPredicate.register_many(Determinant, Factorization, HadamardProduct,
Inverse, MatAdd, Trace, Transpose)
def _(expr, assumptions):
return test_closed_group(expr, assumptions, Q.complex_elements)
@ComplexElementsPredicate.register(MatPow)
def _(expr, assumptions):
# only for integer powers
base, exp = expr.args
int_exp = ask(Q.integer(exp), assumptions)
if not int_exp:
return None
non_negative = ask(~Q.negative(exp), assumptions)
if (non_negative or non_negative == False
and ask(Q.invertible(base), assumptions)):
return ask(Q.complex_elements(base), assumptions)
return None
@ComplexElementsPredicate.register(MatMul)
def _(expr, assumptions):
return MatMul_elements(Q.complex_elements, Q.complex, expr, assumptions)
@ComplexElementsPredicate.register(MatrixSlice)
def _(expr, assumptions):
return MS_elements(Q.complex_elements, expr, assumptions)
@ComplexElementsPredicate.register(BlockMatrix)
def _(expr, assumptions):
return BM_elements(Q.complex_elements, expr, assumptions)
@ComplexElementsPredicate.register(DFT)
def _(expr, assumptions):
return True
PK ]ZZZ�`c c % sympy/assumptions/handlers/ntheory.py"""
Handlers for keys related to number theory: prime, even, odd, etc.
"""
from sympy.assumptions import Q, ask
from sympy.core import Add, Basic, Expr, Float, Mul, Pow, S
from sympy.core.numbers import (ImaginaryUnit, Infinity, Integer, NaN,
NegativeInfinity, NumberSymbol, Rational, int_valued)
from sympy.functions import Abs, im, re
from sympy.ntheory import isprime
from sympy.multipledispatch import MDNotImplementedError
from ..predicates.ntheory import (PrimePredicate, CompositePredicate,
EvenPredicate, OddPredicate)
# PrimePredicate
def _PrimePredicate_number(expr, assumptions):
# helper method
exact = not expr.atoms(Float)
try:
i = int(expr.round())
if (expr - i).equals(0) is False:
raise TypeError
except TypeError:
return False
if exact:
return isprime(i)
# when not exact, we won't give a True or False
# since the number represents an approximate value
@PrimePredicate.register(Expr)
def _(expr, assumptions):
ret = expr.is_prime
if ret is None:
raise MDNotImplementedError
return ret
@PrimePredicate.register(Basic)
def _(expr, assumptions):
if expr.is_number:
return _PrimePredicate_number(expr, assumptions)
@PrimePredicate.register(Mul)
def _(expr, assumptions):
if expr.is_number:
return _PrimePredicate_number(expr, assumptions)
for arg in expr.args:
if not ask(Q.integer(arg), assumptions):
return None
for arg in expr.args:
if arg.is_number and arg.is_composite:
return False
@PrimePredicate.register(Pow)
def _(expr, assumptions):
"""
Integer**Integer -> !Prime
"""
if expr.is_number:
return _PrimePredicate_number(expr, assumptions)
if ask(Q.integer(expr.exp), assumptions) and \
ask(Q.integer(expr.base), assumptions):
return False
@PrimePredicate.register(Integer)
def _(expr, assumptions):
return isprime(expr)
@PrimePredicate.register_many(Rational, Infinity, NegativeInfinity, ImaginaryUnit)
def _(expr, assumptions):
return False
@PrimePredicate.register(Float)
def _(expr, assumptions):
return _PrimePredicate_number(expr, assumptions)
@PrimePredicate.register(NumberSymbol)
def _(expr, assumptions):
return _PrimePredicate_number(expr, assumptions)
@PrimePredicate.register(NaN)
def _(expr, assumptions):
return None
# CompositePredicate
@CompositePredicate.register(Expr)
def _(expr, assumptions):
ret = expr.is_composite
if ret is None:
raise MDNotImplementedError
return ret
@CompositePredicate.register(Basic)
def _(expr, assumptions):
_positive = ask(Q.positive(expr), assumptions)
if _positive:
_integer = ask(Q.integer(expr), assumptions)
if _integer:
_prime = ask(Q.prime(expr), assumptions)
if _prime is None:
return
# Positive integer which is not prime is not
# necessarily composite
if expr.equals(1):
return False
return not _prime
else:
return _integer
else:
return _positive
# EvenPredicate
def _EvenPredicate_number(expr, assumptions):
# helper method
if isinstance(expr, (float, Float)):
if int_valued(expr):
return None
return False
try:
i = int(expr.round())
except TypeError:
return False
if not (expr - i).equals(0):
return False
return i % 2 == 0
@EvenPredicate.register(Expr)
def _(expr, assumptions):
ret = expr.is_even
if ret is None:
raise MDNotImplementedError
return ret
@EvenPredicate.register(Basic)
def _(expr, assumptions):
if expr.is_number:
return _EvenPredicate_number(expr, assumptions)
@EvenPredicate.register(Mul)
def _(expr, assumptions):
"""
Even * Integer -> Even
Even * Odd -> Even
Integer * Odd -> ?
Odd * Odd -> Odd
Even * Even -> Even
Integer * Integer -> Even if Integer + Integer = Odd
otherwise -> ?
"""
if expr.is_number:
return _EvenPredicate_number(expr, assumptions)
even, odd, irrational, acc = False, 0, False, 1
for arg in expr.args:
# check for all integers and at least one even
if ask(Q.integer(arg), assumptions):
if ask(Q.even(arg), assumptions):
even = True
elif ask(Q.odd(arg), assumptions):
odd += 1
elif not even and acc != 1:
if ask(Q.odd(acc + arg), assumptions):
even = True
elif ask(Q.irrational(arg), assumptions):
# one irrational makes the result False
# two makes it undefined
if irrational:
break
irrational = True
else:
break
acc = arg
else:
if irrational:
return False
if even:
return True
if odd == len(expr.args):
return False
@EvenPredicate.register(Add)
def _(expr, assumptions):
"""
Even + Odd -> Odd
Even + Even -> Even
Odd + Odd -> Even
"""
if expr.is_number:
return _EvenPredicate_number(expr, assumptions)
_result = True
for arg in expr.args:
if ask(Q.even(arg), assumptions):
pass
elif ask(Q.odd(arg), assumptions):
_result = not _result
else:
break
else:
return _result
@EvenPredicate.register(Pow)
def _(expr, assumptions):
if expr.is_number:
return _EvenPredicate_number(expr, assumptions)
if ask(Q.integer(expr.exp), assumptions):
if ask(Q.positive(expr.exp), assumptions):
return ask(Q.even(expr.base), assumptions)
elif ask(~Q.negative(expr.exp) & Q.odd(expr.base), assumptions):
return False
elif expr.base is S.NegativeOne:
return False
@EvenPredicate.register(Integer)
def _(expr, assumptions):
return not bool(expr.p & 1)
@EvenPredicate.register_many(Rational, Infinity, NegativeInfinity, ImaginaryUnit)
def _(expr, assumptions):
return False
@EvenPredicate.register(NumberSymbol)
def _(expr, assumptions):
return _EvenPredicate_number(expr, assumptions)
@EvenPredicate.register(Abs)
def _(expr, assumptions):
if ask(Q.real(expr.args[0]), assumptions):
return ask(Q.even(expr.args[0]), assumptions)
@EvenPredicate.register(re)
def _(expr, assumptions):
if ask(Q.real(expr.args[0]), assumptions):
return ask(Q.even(expr.args[0]), assumptions)
@EvenPredicate.register(im)
def _(expr, assumptions):
if ask(Q.real(expr.args[0]), assumptions):
return True
@EvenPredicate.register(NaN)
def _(expr, assumptions):
return None
# OddPredicate
@OddPredicate.register(Expr)
def _(expr, assumptions):
ret = expr.is_odd
if ret is None:
raise MDNotImplementedError
return ret
@OddPredicate.register(Basic)
def _(expr, assumptions):
_integer = ask(Q.integer(expr), assumptions)
if _integer:
_even = ask(Q.even(expr), assumptions)
if _even is None:
return None
return not _even
return _integer
PK ]ZZZ�f^R�/ �/ # sympy/assumptions/handlers/order.py"""
Handlers related to order relations: positive, negative, etc.
"""
from sympy.assumptions import Q, ask
from sympy.core import Add, Basic, Expr, Mul, Pow
from sympy.core.logic import fuzzy_not, fuzzy_and, fuzzy_or
from sympy.core.numbers import E, ImaginaryUnit, NaN, I, pi
from sympy.functions import Abs, acos, acot, asin, atan, exp, factorial, log
from sympy.matrices import Determinant, Trace
from sympy.matrices.expressions.matexpr import MatrixElement
from sympy.multipledispatch import MDNotImplementedError
from ..predicates.order import (NegativePredicate, NonNegativePredicate,
NonZeroPredicate, ZeroPredicate, NonPositivePredicate, PositivePredicate,
ExtendedNegativePredicate, ExtendedNonNegativePredicate,
ExtendedNonPositivePredicate, ExtendedNonZeroPredicate,
ExtendedPositivePredicate,)
# NegativePredicate
def _NegativePredicate_number(expr, assumptions):
r, i = expr.as_real_imag()
# If the imaginary part can symbolically be shown to be zero then
# we just evaluate the real part; otherwise we evaluate the imaginary
# part to see if it actually evaluates to zero and if it does then
# we make the comparison between the real part and zero.
if not i:
r = r.evalf(2)
if r._prec != 1:
return r < 0
else:
i = i.evalf(2)
if i._prec != 1:
if i != 0:
return False
r = r.evalf(2)
if r._prec != 1:
return r < 0
@NegativePredicate.register(Basic)
def _(expr, assumptions):
if expr.is_number:
return _NegativePredicate_number(expr, assumptions)
@NegativePredicate.register(Expr)
def _(expr, assumptions):
ret = expr.is_negative
if ret is None:
raise MDNotImplementedError
return ret
@NegativePredicate.register(Add)
def _(expr, assumptions):
"""
Positive + Positive -> Positive,
Negative + Negative -> Negative
"""
if expr.is_number:
return _NegativePredicate_number(expr, assumptions)
r = ask(Q.real(expr), assumptions)
if r is not True:
return r
nonpos = 0
for arg in expr.args:
if ask(Q.negative(arg), assumptions) is not True:
if ask(Q.positive(arg), assumptions) is False:
nonpos += 1
else:
break
else:
if nonpos < len(expr.args):
return True
@NegativePredicate.register(Mul)
def _(expr, assumptions):
if expr.is_number:
return _NegativePredicate_number(expr, assumptions)
result = None
for arg in expr.args:
if result is None:
result = False
if ask(Q.negative(arg), assumptions):
result = not result
elif ask(Q.positive(arg), assumptions):
pass
else:
return
return result
@NegativePredicate.register(Pow)
def _(expr, assumptions):
"""
Real ** Even -> NonNegative
Real ** Odd -> same_as_base
NonNegative ** Positive -> NonNegative
"""
if expr.base == E:
# Exponential is always positive:
if ask(Q.real(expr.exp), assumptions):
return False
return
if expr.is_number:
return _NegativePredicate_number(expr, assumptions)
if ask(Q.real(expr.base), assumptions):
if ask(Q.positive(expr.base), assumptions):
if ask(Q.real(expr.exp), assumptions):
return False
if ask(Q.even(expr.exp), assumptions):
return False
if ask(Q.odd(expr.exp), assumptions):
return ask(Q.negative(expr.base), assumptions)
@NegativePredicate.register_many(Abs, ImaginaryUnit)
def _(expr, assumptions):
return False
@NegativePredicate.register(exp)
def _(expr, assumptions):
if ask(Q.real(expr.exp), assumptions):
return False
raise MDNotImplementedError
# NonNegativePredicate
@NonNegativePredicate.register(Basic)
def _(expr, assumptions):
if expr.is_number:
notnegative = fuzzy_not(_NegativePredicate_number(expr, assumptions))
if notnegative:
return ask(Q.real(expr), assumptions)
else:
return notnegative
@NonNegativePredicate.register(Expr)
def _(expr, assumptions):
ret = expr.is_nonnegative
if ret is None:
raise MDNotImplementedError
return ret
# NonZeroPredicate
@NonZeroPredicate.register(Expr)
def _(expr, assumptions):
ret = expr.is_nonzero
if ret is None:
raise MDNotImplementedError
return ret
@NonZeroPredicate.register(Basic)
def _(expr, assumptions):
if ask(Q.real(expr)) is False:
return False
if expr.is_number:
# if there are no symbols just evalf
i = expr.evalf(2)
def nonz(i):
if i._prec != 1:
return i != 0
return fuzzy_or(nonz(i) for i in i.as_real_imag())
@NonZeroPredicate.register(Add)
def _(expr, assumptions):
if all(ask(Q.positive(x), assumptions) for x in expr.args) \
or all(ask(Q.negative(x), assumptions) for x in expr.args):
return True
@NonZeroPredicate.register(Mul)
def _(expr, assumptions):
for arg in expr.args:
result = ask(Q.nonzero(arg), assumptions)
if result:
continue
return result
return True
@NonZeroPredicate.register(Pow)
def _(expr, assumptions):
return ask(Q.nonzero(expr.base), assumptions)
@NonZeroPredicate.register(Abs)
def _(expr, assumptions):
return ask(Q.nonzero(expr.args[0]), assumptions)
@NonZeroPredicate.register(NaN)
def _(expr, assumptions):
return None
# ZeroPredicate
@ZeroPredicate.register(Expr)
def _(expr, assumptions):
ret = expr.is_zero
if ret is None:
raise MDNotImplementedError
return ret
@ZeroPredicate.register(Basic)
def _(expr, assumptions):
return fuzzy_and([fuzzy_not(ask(Q.nonzero(expr), assumptions)),
ask(Q.real(expr), assumptions)])
@ZeroPredicate.register(Mul)
def _(expr, assumptions):
# TODO: This should be deducible from the nonzero handler
return fuzzy_or(ask(Q.zero(arg), assumptions) for arg in expr.args)
# NonPositivePredicate
@NonPositivePredicate.register(Expr)
def _(expr, assumptions):
ret = expr.is_nonpositive
if ret is None:
raise MDNotImplementedError
return ret
@NonPositivePredicate.register(Basic)
def _(expr, assumptions):
if expr.is_number:
notpositive = fuzzy_not(_PositivePredicate_number(expr, assumptions))
if notpositive:
return ask(Q.real(expr), assumptions)
else:
return notpositive
# PositivePredicate
def _PositivePredicate_number(expr, assumptions):
r, i = expr.as_real_imag()
# If the imaginary part can symbolically be shown to be zero then
# we just evaluate the real part; otherwise we evaluate the imaginary
# part to see if it actually evaluates to zero and if it does then
# we make the comparison between the real part and zero.
if not i:
r = r.evalf(2)
if r._prec != 1:
return r > 0
else:
i = i.evalf(2)
if i._prec != 1:
if i != 0:
return False
r = r.evalf(2)
if r._prec != 1:
return r > 0
@PositivePredicate.register(Expr)
def _(expr, assumptions):
ret = expr.is_positive
if ret is None:
raise MDNotImplementedError
return ret
@PositivePredicate.register(Basic)
def _(expr, assumptions):
if expr.is_number:
return _PositivePredicate_number(expr, assumptions)
@PositivePredicate.register(Mul)
def _(expr, assumptions):
if expr.is_number:
return _PositivePredicate_number(expr, assumptions)
result = True
for arg in expr.args:
if ask(Q.positive(arg), assumptions):
continue
elif ask(Q.negative(arg), assumptions):
result = result ^ True
else:
return
return result
@PositivePredicate.register(Add)
def _(expr, assumptions):
if expr.is_number:
return _PositivePredicate_number(expr, assumptions)
r = ask(Q.real(expr), assumptions)
if r is not True:
return r
nonneg = 0
for arg in expr.args:
if ask(Q.positive(arg), assumptions) is not True:
if ask(Q.negative(arg), assumptions) is False:
nonneg += 1
else:
break
else:
if nonneg < len(expr.args):
return True
@PositivePredicate.register(Pow)
def _(expr, assumptions):
if expr.base == E:
if ask(Q.real(expr.exp), assumptions):
return True
if ask(Q.imaginary(expr.exp), assumptions):
return ask(Q.even(expr.exp/(I*pi)), assumptions)
return
if expr.is_number:
return _PositivePredicate_number(expr, assumptions)
if ask(Q.positive(expr.base), assumptions):
if ask(Q.real(expr.exp), assumptions):
return True
if ask(Q.negative(expr.base), assumptions):
if ask(Q.even(expr.exp), assumptions):
return True
if ask(Q.odd(expr.exp), assumptions):
return False
@PositivePredicate.register(exp)
def _(expr, assumptions):
if ask(Q.real(expr.exp), assumptions):
return True
if ask(Q.imaginary(expr.exp), assumptions):
return ask(Q.even(expr.exp/(I*pi)), assumptions)
@PositivePredicate.register(log)
def _(expr, assumptions):
r = ask(Q.real(expr.args[0]), assumptions)
if r is not True:
return r
if ask(Q.positive(expr.args[0] - 1), assumptions):
return True
if ask(Q.negative(expr.args[0] - 1), assumptions):
return False
@PositivePredicate.register(factorial)
def _(expr, assumptions):
x = expr.args[0]
if ask(Q.integer(x) & Q.positive(x), assumptions):
return True
@PositivePredicate.register(ImaginaryUnit)
def _(expr, assumptions):
return False
@PositivePredicate.register(Abs)
def _(expr, assumptions):
return ask(Q.nonzero(expr), assumptions)
@PositivePredicate.register(Trace)
def _(expr, assumptions):
if ask(Q.positive_definite(expr.arg), assumptions):
return True
@PositivePredicate.register(Determinant)
def _(expr, assumptions):
if ask(Q.positive_definite(expr.arg), assumptions):
return True
@PositivePredicate.register(MatrixElement)
def _(expr, assumptions):
if (expr.i == expr.j
and ask(Q.positive_definite(expr.parent), assumptions)):
return True
@PositivePredicate.register(atan)
def _(expr, assumptions):
return ask(Q.positive(expr.args[0]), assumptions)
@PositivePredicate.register(asin)
def _(expr, assumptions):
x = expr.args[0]
if ask(Q.positive(x) & Q.nonpositive(x - 1), assumptions):
return True
if ask(Q.negative(x) & Q.nonnegative(x + 1), assumptions):
return False
@PositivePredicate.register(acos)
def _(expr, assumptions):
x = expr.args[0]
if ask(Q.nonpositive(x - 1) & Q.nonnegative(x + 1), assumptions):
return True
@PositivePredicate.register(acot)
def _(expr, assumptions):
return ask(Q.real(expr.args[0]), assumptions)
@PositivePredicate.register(NaN)
def _(expr, assumptions):
return None
# ExtendedNegativePredicate
@ExtendedNegativePredicate.register(object)
def _(expr, assumptions):
return ask(Q.negative(expr) | Q.negative_infinite(expr), assumptions)
# ExtendedPositivePredicate
@ExtendedPositivePredicate.register(object)
def _(expr, assumptions):
return ask(Q.positive(expr) | Q.positive_infinite(expr), assumptions)
# ExtendedNonZeroPredicate
@ExtendedNonZeroPredicate.register(object)
def _(expr, assumptions):
return ask(
Q.negative_infinite(expr) | Q.negative(expr) | Q.positive(expr) | Q.positive_infinite(expr),
assumptions)
# ExtendedNonPositivePredicate
@ExtendedNonPositivePredicate.register(object)
def _(expr, assumptions):
return ask(
Q.negative_infinite(expr) | Q.negative(expr) | Q.zero(expr),
assumptions)
# ExtendedNonNegativePredicate
@ExtendedNonNegativePredicate.register(object)
def _(expr, assumptions):
return ask(
Q.zero(expr) | Q.positive(expr) | Q.positive_infinite(expr),
assumptions)
PK ]ZZZ ?S�
]
] " sympy/assumptions/handlers/sets.py"""
Handlers for predicates related to set membership: integer, rational, etc.
"""
from sympy.assumptions import Q, ask
from sympy.core import Add, Basic, Expr, Mul, Pow, S
from sympy.core.numbers import (AlgebraicNumber, ComplexInfinity, Exp1, Float,
GoldenRatio, ImaginaryUnit, Infinity, Integer, NaN, NegativeInfinity,
Number, NumberSymbol, Pi, pi, Rational, TribonacciConstant, E)
from sympy.core.logic import fuzzy_bool
from sympy.functions import (Abs, acos, acot, asin, atan, cos, cot, exp, im,
log, re, sin, tan)
from sympy.core.numbers import I
from sympy.core.relational import Eq
from sympy.functions.elementary.complexes import conjugate
from sympy.matrices import Determinant, MatrixBase, Trace
from sympy.matrices.expressions.matexpr import MatrixElement
from sympy.multipledispatch import MDNotImplementedError
from .common import test_closed_group
from ..predicates.sets import (IntegerPredicate, RationalPredicate,
IrrationalPredicate, RealPredicate, ExtendedRealPredicate,
HermitianPredicate, ComplexPredicate, ImaginaryPredicate,
AntihermitianPredicate, AlgebraicPredicate)
# IntegerPredicate
def _IntegerPredicate_number(expr, assumptions):
# helper function
try:
i = int(expr.round())
if not (expr - i).equals(0):
raise TypeError
return True
except TypeError:
return False
@IntegerPredicate.register_many(int, Integer) # type:ignore
def _(expr, assumptions):
return True
@IntegerPredicate.register_many(Exp1, GoldenRatio, ImaginaryUnit, Infinity,
NegativeInfinity, Pi, Rational, TribonacciConstant)
def _(expr, assumptions):
return False
@IntegerPredicate.register(Expr)
def _(expr, assumptions):
ret = expr.is_integer
if ret is None:
raise MDNotImplementedError
return ret
@IntegerPredicate.register_many(Add, Pow)
def _(expr, assumptions):
"""
* Integer + Integer -> Integer
* Integer + !Integer -> !Integer
* !Integer + !Integer -> ?
"""
if expr.is_number:
return _IntegerPredicate_number(expr, assumptions)
return test_closed_group(expr, assumptions, Q.integer)
@IntegerPredicate.register(Mul)
def _(expr, assumptions):
"""
* Integer*Integer -> Integer
* Integer*Irrational -> !Integer
* Odd/Even -> !Integer
* Integer*Rational -> ?
"""
if expr.is_number:
return _IntegerPredicate_number(expr, assumptions)
_output = True
for arg in expr.args:
if not ask(Q.integer(arg), assumptions):
if arg.is_Rational:
if arg.q == 2:
return ask(Q.even(2*expr), assumptions)
if ~(arg.q & 1):
return None
elif ask(Q.irrational(arg), assumptions):
if _output:
_output = False
else:
return
else:
return
return _output
@IntegerPredicate.register(Abs)
def _(expr, assumptions):
return ask(Q.integer(expr.args[0]), assumptions)
@IntegerPredicate.register_many(Determinant, MatrixElement, Trace)
def _(expr, assumptions):
return ask(Q.integer_elements(expr.args[0]), assumptions)
# RationalPredicate
@RationalPredicate.register(Rational)
def _(expr, assumptions):
return True
@RationalPredicate.register(Float)
def _(expr, assumptions):
return None
@RationalPredicate.register_many(Exp1, GoldenRatio, ImaginaryUnit, Infinity,
NegativeInfinity, Pi, TribonacciConstant)
def _(expr, assumptions):
return False
@RationalPredicate.register(Expr)
def _(expr, assumptions):
ret = expr.is_rational
if ret is None:
raise MDNotImplementedError
return ret
@RationalPredicate.register_many(Add, Mul)
def _(expr, assumptions):
"""
* Rational + Rational -> Rational
* Rational + !Rational -> !Rational
* !Rational + !Rational -> ?
"""
if expr.is_number:
if expr.as_real_imag()[1]:
return False
return test_closed_group(expr, assumptions, Q.rational)
@RationalPredicate.register(Pow)
def _(expr, assumptions):
"""
* Rational ** Integer -> Rational
* Irrational ** Rational -> Irrational
* Rational ** Irrational -> ?
"""
if expr.base == E:
x = expr.exp
if ask(Q.rational(x), assumptions):
return ask(~Q.nonzero(x), assumptions)
return
if ask(Q.integer(expr.exp), assumptions):
return ask(Q.rational(expr.base), assumptions)
elif ask(Q.rational(expr.exp), assumptions):
if ask(Q.prime(expr.base), assumptions):
return False
@RationalPredicate.register_many(asin, atan, cos, sin, tan)
def _(expr, assumptions):
x = expr.args[0]
if ask(Q.rational(x), assumptions):
return ask(~Q.nonzero(x), assumptions)
@RationalPredicate.register(exp)
def _(expr, assumptions):
x = expr.exp
if ask(Q.rational(x), assumptions):
return ask(~Q.nonzero(x), assumptions)
@RationalPredicate.register_many(acot, cot)
def _(expr, assumptions):
x = expr.args[0]
if ask(Q.rational(x), assumptions):
return False
@RationalPredicate.register_many(acos, log)
def _(expr, assumptions):
x = expr.args[0]
if ask(Q.rational(x), assumptions):
return ask(~Q.nonzero(x - 1), assumptions)
# IrrationalPredicate
@IrrationalPredicate.register(Expr)
def _(expr, assumptions):
ret = expr.is_irrational
if ret is None:
raise MDNotImplementedError
return ret
@IrrationalPredicate.register(Basic)
def _(expr, assumptions):
_real = ask(Q.real(expr), assumptions)
if _real:
_rational = ask(Q.rational(expr), assumptions)
if _rational is None:
return None
return not _rational
else:
return _real
# RealPredicate
def _RealPredicate_number(expr, assumptions):
# let as_real_imag() work first since the expression may
# be simpler to evaluate
i = expr.as_real_imag()[1].evalf(2)
if i._prec != 1:
return not i
# allow None to be returned if we couldn't show for sure
# that i was 0
@RealPredicate.register_many(Abs, Exp1, Float, GoldenRatio, im, Pi, Rational,
re, TribonacciConstant)
def _(expr, assumptions):
return True
@RealPredicate.register_many(ImaginaryUnit, Infinity, NegativeInfinity)
def _(expr, assumptions):
return False
@RealPredicate.register(Expr)
def _(expr, assumptions):
ret = expr.is_real
if ret is None:
raise MDNotImplementedError
return ret
@RealPredicate.register(Add)
def _(expr, assumptions):
"""
* Real + Real -> Real
* Real + (Complex & !Real) -> !Real
"""
if expr.is_number:
return _RealPredicate_number(expr, assumptions)
return test_closed_group(expr, assumptions, Q.real)
@RealPredicate.register(Mul)
def _(expr, assumptions):
"""
* Real*Real -> Real
* Real*Imaginary -> !Real
* Imaginary*Imaginary -> Real
"""
if expr.is_number:
return _RealPredicate_number(expr, assumptions)
result = True
for arg in expr.args:
if ask(Q.real(arg), assumptions):
pass
elif ask(Q.imaginary(arg), assumptions):
result = result ^ True
else:
break
else:
return result
@RealPredicate.register(Pow)
def _(expr, assumptions):
"""
* Real**Integer -> Real
* Positive**Real -> Real
* Real**(Integer/Even) -> Real if base is nonnegative
* Real**(Integer/Odd) -> Real
* Imaginary**(Integer/Even) -> Real
* Imaginary**(Integer/Odd) -> not Real
* Imaginary**Real -> ? since Real could be 0 (giving real)
or 1 (giving imaginary)
* b**Imaginary -> Real if log(b) is imaginary and b != 0
and exponent != integer multiple of
I*pi/log(b)
* Real**Real -> ? e.g. sqrt(-1) is imaginary and
sqrt(2) is not
"""
if expr.is_number:
return _RealPredicate_number(expr, assumptions)
if expr.base == E:
return ask(
Q.integer(expr.exp/I/pi) | Q.real(expr.exp), assumptions
)
if expr.base.func == exp or (expr.base.is_Pow and expr.base.base == E):
if ask(Q.imaginary(expr.base.exp), assumptions):
if ask(Q.imaginary(expr.exp), assumptions):
return True
# If the i = (exp's arg)/(I*pi) is an integer or half-integer
# multiple of I*pi then 2*i will be an integer. In addition,
# exp(i*I*pi) = (-1)**i so the overall realness of the expr
# can be determined by replacing exp(i*I*pi) with (-1)**i.
i = expr.base.exp/I/pi
if ask(Q.integer(2*i), assumptions):
return ask(Q.real((S.NegativeOne**i)**expr.exp), assumptions)
return
if ask(Q.imaginary(expr.base), assumptions):
if ask(Q.integer(expr.exp), assumptions):
odd = ask(Q.odd(expr.exp), assumptions)
if odd is not None:
return not odd
return
if ask(Q.imaginary(expr.exp), assumptions):
imlog = ask(Q.imaginary(log(expr.base)), assumptions)
if imlog is not None:
# I**i -> real, log(I) is imag;
# (2*I)**i -> complex, log(2*I) is not imag
return imlog
if ask(Q.real(expr.base), assumptions):
if ask(Q.real(expr.exp), assumptions):
if expr.exp.is_Rational and \
ask(Q.even(expr.exp.q), assumptions):
return ask(Q.positive(expr.base), assumptions)
elif ask(Q.integer(expr.exp), assumptions):
return True
elif ask(Q.positive(expr.base), assumptions):
return True
elif ask(Q.negative(expr.base), assumptions):
return False
@RealPredicate.register_many(cos, sin)
def _(expr, assumptions):
if ask(Q.real(expr.args[0]), assumptions):
return True
@RealPredicate.register(exp)
def _(expr, assumptions):
return ask(
Q.integer(expr.exp/I/pi) | Q.real(expr.exp), assumptions
)
@RealPredicate.register(log)
def _(expr, assumptions):
return ask(Q.positive(expr.args[0]), assumptions)
@RealPredicate.register_many(Determinant, MatrixElement, Trace)
def _(expr, assumptions):
return ask(Q.real_elements(expr.args[0]), assumptions)
# ExtendedRealPredicate
@ExtendedRealPredicate.register(object)
def _(expr, assumptions):
return ask(Q.negative_infinite(expr)
| Q.negative(expr)
| Q.zero(expr)
| Q.positive(expr)
| Q.positive_infinite(expr),
assumptions)
@ExtendedRealPredicate.register_many(Infinity, NegativeInfinity)
def _(expr, assumptions):
return True
@ExtendedRealPredicate.register_many(Add, Mul, Pow) # type:ignore
def _(expr, assumptions):
return test_closed_group(expr, assumptions, Q.extended_real)
# HermitianPredicate
@HermitianPredicate.register(object) # type:ignore
def _(expr, assumptions):
if isinstance(expr, MatrixBase):
return None
return ask(Q.real(expr), assumptions)
@HermitianPredicate.register(Add) # type:ignore
def _(expr, assumptions):
"""
* Hermitian + Hermitian -> Hermitian
* Hermitian + !Hermitian -> !Hermitian
"""
if expr.is_number:
raise MDNotImplementedError
return test_closed_group(expr, assumptions, Q.hermitian)
@HermitianPredicate.register(Mul) # type:ignore
def _(expr, assumptions):
"""
As long as there is at most only one noncommutative term:
* Hermitian*Hermitian -> Hermitian
* Hermitian*Antihermitian -> !Hermitian
* Antihermitian*Antihermitian -> Hermitian
"""
if expr.is_number:
raise MDNotImplementedError
nccount = 0
result = True
for arg in expr.args:
if ask(Q.antihermitian(arg), assumptions):
result = result ^ True
elif not ask(Q.hermitian(arg), assumptions):
break
if ask(~Q.commutative(arg), assumptions):
nccount += 1
if nccount > 1:
break
else:
return result
@HermitianPredicate.register(Pow) # type:ignore
def _(expr, assumptions):
"""
* Hermitian**Integer -> Hermitian
"""
if expr.is_number:
raise MDNotImplementedError
if expr.base == E:
if ask(Q.hermitian(expr.exp), assumptions):
return True
raise MDNotImplementedError
if ask(Q.hermitian(expr.base), assumptions):
if ask(Q.integer(expr.exp), assumptions):
return True
raise MDNotImplementedError
@HermitianPredicate.register_many(cos, sin) # type:ignore
def _(expr, assumptions):
if ask(Q.hermitian(expr.args[0]), assumptions):
return True
raise MDNotImplementedError
@HermitianPredicate.register(exp) # type:ignore
def _(expr, assumptions):
if ask(Q.hermitian(expr.exp), assumptions):
return True
raise MDNotImplementedError
@HermitianPredicate.register(MatrixBase) # type:ignore
def _(mat, assumptions):
rows, cols = mat.shape
ret_val = True
for i in range(rows):
for j in range(i, cols):
cond = fuzzy_bool(Eq(mat[i, j], conjugate(mat[j, i])))
if cond is None:
ret_val = None
if cond == False:
return False
if ret_val is None:
raise MDNotImplementedError
return ret_val
# ComplexPredicate
@ComplexPredicate.register_many(Abs, cos, exp, im, ImaginaryUnit, log, Number, # type:ignore
NumberSymbol, re, sin)
def _(expr, assumptions):
return True
@ComplexPredicate.register_many(Infinity, NegativeInfinity) # type:ignore
def _(expr, assumptions):
return False
@ComplexPredicate.register(Expr) # type:ignore
def _(expr, assumptions):
ret = expr.is_complex
if ret is None:
raise MDNotImplementedError
return ret
@ComplexPredicate.register_many(Add, Mul) # type:ignore
def _(expr, assumptions):
return test_closed_group(expr, assumptions, Q.complex)
@ComplexPredicate.register(Pow) # type:ignore
def _(expr, assumptions):
if expr.base == E:
return True
return test_closed_group(expr, assumptions, Q.complex)
@ComplexPredicate.register_many(Determinant, MatrixElement, Trace) # type:ignore
def _(expr, assumptions):
return ask(Q.complex_elements(expr.args[0]), assumptions)
@ComplexPredicate.register(NaN) # type:ignore
def _(expr, assumptions):
return None
# ImaginaryPredicate
def _Imaginary_number(expr, assumptions):
# let as_real_imag() work first since the expression may
# be simpler to evaluate
r = expr.as_real_imag()[0].evalf(2)
if r._prec != 1:
return not r
# allow None to be returned if we couldn't show for sure
# that r was 0
@ImaginaryPredicate.register(ImaginaryUnit) # type:ignore
def _(expr, assumptions):
return True
@ImaginaryPredicate.register(Expr) # type:ignore
def _(expr, assumptions):
ret = expr.is_imaginary
if ret is None:
raise MDNotImplementedError
return ret
@ImaginaryPredicate.register(Add) # type:ignore
def _(expr, assumptions):
"""
* Imaginary + Imaginary -> Imaginary
* Imaginary + Complex -> ?
* Imaginary + Real -> !Imaginary
"""
if expr.is_number:
return _Imaginary_number(expr, assumptions)
reals = 0
for arg in expr.args:
if ask(Q.imaginary(arg), assumptions):
pass
elif ask(Q.real(arg), assumptions):
reals += 1
else:
break
else:
if reals == 0:
return True
if reals in (1, len(expr.args)):
# two reals could sum 0 thus giving an imaginary
return False
@ImaginaryPredicate.register(Mul) # type:ignore
def _(expr, assumptions):
"""
* Real*Imaginary -> Imaginary
* Imaginary*Imaginary -> Real
"""
if expr.is_number:
return _Imaginary_number(expr, assumptions)
result = False
reals = 0
for arg in expr.args:
if ask(Q.imaginary(arg), assumptions):
result = result ^ True
elif not ask(Q.real(arg), assumptions):
break
else:
if reals == len(expr.args):
return False
return result
@ImaginaryPredicate.register(Pow) # type:ignore
def _(expr, assumptions):
"""
* Imaginary**Odd -> Imaginary
* Imaginary**Even -> Real
* b**Imaginary -> !Imaginary if exponent is an integer
multiple of I*pi/log(b)
* Imaginary**Real -> ?
* Positive**Real -> Real
* Negative**Integer -> Real
* Negative**(Integer/2) -> Imaginary
* Negative**Real -> not Imaginary if exponent is not Rational
"""
if expr.is_number:
return _Imaginary_number(expr, assumptions)
if expr.base == E:
a = expr.exp/I/pi
return ask(Q.integer(2*a) & ~Q.integer(a), assumptions)
if expr.base.func == exp or (expr.base.is_Pow and expr.base.base == E):
if ask(Q.imaginary(expr.base.exp), assumptions):
if ask(Q.imaginary(expr.exp), assumptions):
return False
i = expr.base.exp/I/pi
if ask(Q.integer(2*i), assumptions):
return ask(Q.imaginary((S.NegativeOne**i)**expr.exp), assumptions)
if ask(Q.imaginary(expr.base), assumptions):
if ask(Q.integer(expr.exp), assumptions):
odd = ask(Q.odd(expr.exp), assumptions)
if odd is not None:
return odd
return
if ask(Q.imaginary(expr.exp), assumptions):
imlog = ask(Q.imaginary(log(expr.base)), assumptions)
if imlog is not None:
# I**i -> real; (2*I)**i -> complex ==> not imaginary
return False
if ask(Q.real(expr.base) & Q.real(expr.exp), assumptions):
if ask(Q.positive(expr.base), assumptions):
return False
else:
rat = ask(Q.rational(expr.exp), assumptions)
if not rat:
return rat
if ask(Q.integer(expr.exp), assumptions):
return False
else:
half = ask(Q.integer(2*expr.exp), assumptions)
if half:
return ask(Q.negative(expr.base), assumptions)
return half
@ImaginaryPredicate.register(log) # type:ignore
def _(expr, assumptions):
if ask(Q.real(expr.args[0]), assumptions):
if ask(Q.positive(expr.args[0]), assumptions):
return False
return
# XXX it should be enough to do
# return ask(Q.nonpositive(expr.args[0]), assumptions)
# but ask(Q.nonpositive(exp(x)), Q.imaginary(x)) -> None;
# it should return True since exp(x) will be either 0 or complex
if expr.args[0].func == exp or (expr.args[0].is_Pow and expr.args[0].base == E):
if expr.args[0].exp in [I, -I]:
return True
im = ask(Q.imaginary(expr.args[0]), assumptions)
if im is False:
return False
@ImaginaryPredicate.register(exp) # type:ignore
def _(expr, assumptions):
a = expr.exp/I/pi
return ask(Q.integer(2*a) & ~Q.integer(a), assumptions)
@ImaginaryPredicate.register_many(Number, NumberSymbol) # type:ignore
def _(expr, assumptions):
return not (expr.as_real_imag()[1] == 0)
@ImaginaryPredicate.register(NaN) # type:ignore
def _(expr, assumptions):
return None
# AntihermitianPredicate
@AntihermitianPredicate.register(object) # type:ignore
def _(expr, assumptions):
if isinstance(expr, MatrixBase):
return None
if ask(Q.zero(expr), assumptions):
return True
return ask(Q.imaginary(expr), assumptions)
@AntihermitianPredicate.register(Add) # type:ignore
def _(expr, assumptions):
"""
* Antihermitian + Antihermitian -> Antihermitian
* Antihermitian + !Antihermitian -> !Antihermitian
"""
if expr.is_number:
raise MDNotImplementedError
return test_closed_group(expr, assumptions, Q.antihermitian)
@AntihermitianPredicate.register(Mul) # type:ignore
def _(expr, assumptions):
"""
As long as there is at most only one noncommutative term:
* Hermitian*Hermitian -> !Antihermitian
* Hermitian*Antihermitian -> Antihermitian
* Antihermitian*Antihermitian -> !Antihermitian
"""
if expr.is_number:
raise MDNotImplementedError
nccount = 0
result = False
for arg in expr.args:
if ask(Q.antihermitian(arg), assumptions):
result = result ^ True
elif not ask(Q.hermitian(arg), assumptions):
break
if ask(~Q.commutative(arg), assumptions):
nccount += 1
if nccount > 1:
break
else:
return result
@AntihermitianPredicate.register(Pow) # type:ignore
def _(expr, assumptions):
"""
* Hermitian**Integer -> !Antihermitian
* Antihermitian**Even -> !Antihermitian
* Antihermitian**Odd -> Antihermitian
"""
if expr.is_number:
raise MDNotImplementedError
if ask(Q.hermitian(expr.base), assumptions):
if ask(Q.integer(expr.exp), assumptions):
return False
elif ask(Q.antihermitian(expr.base), assumptions):
if ask(Q.even(expr.exp), assumptions):
return False
elif ask(Q.odd(expr.exp), assumptions):
return True
raise MDNotImplementedError
@AntihermitianPredicate.register(MatrixBase) # type:ignore
def _(mat, assumptions):
rows, cols = mat.shape
ret_val = True
for i in range(rows):
for j in range(i, cols):
cond = fuzzy_bool(Eq(mat[i, j], -conjugate(mat[j, i])))
if cond is None:
ret_val = None
if cond == False:
return False
if ret_val is None:
raise MDNotImplementedError
return ret_val
# AlgebraicPredicate
@AlgebraicPredicate.register_many(AlgebraicNumber, Float, GoldenRatio, # type:ignore
ImaginaryUnit, TribonacciConstant)
def _(expr, assumptions):
return True
@AlgebraicPredicate.register_many(ComplexInfinity, Exp1, Infinity, # type:ignore
NegativeInfinity, Pi)
def _(expr, assumptions):
return False
@AlgebraicPredicate.register_many(Add, Mul) # type:ignore
def _(expr, assumptions):
return test_closed_group(expr, assumptions, Q.algebraic)
@AlgebraicPredicate.register(Pow) # type:ignore
def _(expr, assumptions):
if expr.base == E:
if ask(Q.algebraic(expr.exp), assumptions):
return ask(~Q.nonzero(expr.exp), assumptions)
return
return expr.exp.is_Rational and ask(Q.algebraic(expr.base), assumptions)
@AlgebraicPredicate.register(Rational) # type:ignore
def _(expr, assumptions):
return expr.q != 0
@AlgebraicPredicate.register_many(asin, atan, cos, sin, tan) # type:ignore
def _(expr, assumptions):
x = expr.args[0]
if ask(Q.algebraic(x), assumptions):
return ask(~Q.nonzero(x), assumptions)
@AlgebraicPredicate.register(exp) # type:ignore
def _(expr, assumptions):
x = expr.exp
if ask(Q.algebraic(x), assumptions):
return ask(~Q.nonzero(x), assumptions)
@AlgebraicPredicate.register_many(acot, cot) # type:ignore
def _(expr, assumptions):
x = expr.args[0]
if ask(Q.algebraic(x), assumptions):
return False
@AlgebraicPredicate.register_many(acos, log) # type:ignore
def _(expr, assumptions):
x = expr.args[0]
if ask(Q.algebraic(x), assumptions):
return ask(~Q.nonzero(x - 1), assumptions)
PK ]ZZZ����n n ( sympy/assumptions/predicates/__init__.py"""
Module to implement predicate classes.
Class of every predicate registered to ``Q`` is defined here.
"""
PK ]ZZZ� a a ( sympy/assumptions/predicates/calculus.pyfrom sympy.assumptions import Predicate
from sympy.multipledispatch import Dispatcher
class FinitePredicate(Predicate):
"""
Finite number predicate.
Explanation
===========
``Q.finite(x)`` is true if ``x`` is a number but neither an infinity
nor a ``NaN``. In other words, ``ask(Q.finite(x))`` is true for all
numerical ``x`` having a bounded absolute value.
Examples
========
>>> from sympy import Q, ask, S, oo, I, zoo
>>> from sympy.abc import x
>>> ask(Q.finite(oo))
False
>>> ask(Q.finite(-oo))
False
>>> ask(Q.finite(zoo))
False
>>> ask(Q.finite(1))
True
>>> ask(Q.finite(2 + 3*I))
True
>>> ask(Q.finite(x), Q.positive(x))
True
>>> print(ask(Q.finite(S.NaN)))
None
References
==========
.. [1] https://en.wikipedia.org/wiki/Finite
"""
name = 'finite'
handler = Dispatcher(
"FiniteHandler",
doc=("Handler for Q.finite. Test that an expression is bounded respect"
" to all its variables.")
)
class InfinitePredicate(Predicate):
"""
Infinite number predicate.
``Q.infinite(x)`` is true iff the absolute value of ``x`` is
infinity.
"""
# TODO: Add examples
name = 'infinite'
handler = Dispatcher(
"InfiniteHandler",
doc="""Handler for Q.infinite key."""
)
class PositiveInfinitePredicate(Predicate):
"""
Positive infinity predicate.
``Q.positive_infinite(x)`` is true iff ``x`` is positive infinity ``oo``.
"""
name = 'positive_infinite'
handler = Dispatcher("PositiveInfiniteHandler")
class NegativeInfinitePredicate(Predicate):
"""
Negative infinity predicate.
``Q.negative_infinite(x)`` is true iff ``x`` is negative infinity ``-oo``.
"""
name = 'negative_infinite'
handler = Dispatcher("NegativeInfiniteHandler")
PK ]ZZZp��� � & sympy/assumptions/predicates/common.pyfrom sympy.assumptions import Predicate, AppliedPredicate, Q
from sympy.core.relational import Eq, Ne, Gt, Lt, Ge, Le
from sympy.multipledispatch import Dispatcher
class CommutativePredicate(Predicate):
"""
Commutative predicate.
Explanation
===========
``ask(Q.commutative(x))`` is true iff ``x`` commutes with any other
object with respect to multiplication operation.
"""
# TODO: Add examples
name = 'commutative'
handler = Dispatcher("CommutativeHandler", doc="Handler for key 'commutative'.")
binrelpreds = {Eq: Q.eq, Ne: Q.ne, Gt: Q.gt, Lt: Q.lt, Ge: Q.ge, Le: Q.le}
class IsTruePredicate(Predicate):
"""
Generic predicate.
Explanation
===========
``ask(Q.is_true(x))`` is true iff ``x`` is true. This only makes
sense if ``x`` is a boolean object.
Examples
========
>>> from sympy import ask, Q
>>> from sympy.abc import x, y
>>> ask(Q.is_true(True))
True
Wrapping another applied predicate just returns the applied predicate.
>>> Q.is_true(Q.even(x))
Q.even(x)
Wrapping binary relation classes in SymPy core returns applied binary
relational predicates.
>>> from sympy import Eq, Gt
>>> Q.is_true(Eq(x, y))
Q.eq(x, y)
>>> Q.is_true(Gt(x, y))
Q.gt(x, y)
Notes
=====
This class is designed to wrap the boolean objects so that they can
behave as if they are applied predicates. Consequently, wrapping another
applied predicate is unnecessary and thus it just returns the argument.
Also, binary relation classes in SymPy core have binary predicates to
represent themselves and thus wrapping them with ``Q.is_true`` converts them
to these applied predicates.
"""
name = 'is_true'
handler = Dispatcher(
"IsTrueHandler",
doc="Wrapper allowing to query the truth value of a boolean expression."
)
def __call__(self, arg):
# No need to wrap another predicate
if isinstance(arg, AppliedPredicate):
return arg
# Convert relational predicates instead of wrapping them
if getattr(arg, "is_Relational", False):
pred = binrelpreds[type(arg)]
return pred(*arg.args)
return super().__call__(arg)
PK ]ZZZ�Ïn/ n/ ( sympy/assumptions/predicates/matrices.pyfrom sympy.assumptions import Predicate
from sympy.multipledispatch import Dispatcher
class SquarePredicate(Predicate):
"""
Square matrix predicate.
Explanation
===========
``Q.square(x)`` is true iff ``x`` is a square matrix. A square matrix
is a matrix with the same number of rows and columns.
Examples
========
>>> from sympy import Q, ask, MatrixSymbol, ZeroMatrix, Identity
>>> X = MatrixSymbol('X', 2, 2)
>>> Y = MatrixSymbol('X', 2, 3)
>>> ask(Q.square(X))
True
>>> ask(Q.square(Y))
False
>>> ask(Q.square(ZeroMatrix(3, 3)))
True
>>> ask(Q.square(Identity(3)))
True
References
==========
.. [1] https://en.wikipedia.org/wiki/Square_matrix
"""
name = 'square'
handler = Dispatcher("SquareHandler", doc="Handler for Q.square.")
class SymmetricPredicate(Predicate):
"""
Symmetric matrix predicate.
Explanation
===========
``Q.symmetric(x)`` is true iff ``x`` is a square matrix and is equal to
its transpose. Every square diagonal matrix is a symmetric matrix.
Examples
========
>>> from sympy import Q, ask, MatrixSymbol
>>> X = MatrixSymbol('X', 2, 2)
>>> Y = MatrixSymbol('Y', 2, 3)
>>> Z = MatrixSymbol('Z', 2, 2)
>>> ask(Q.symmetric(X*Z), Q.symmetric(X) & Q.symmetric(Z))
True
>>> ask(Q.symmetric(X + Z), Q.symmetric(X) & Q.symmetric(Z))
True
>>> ask(Q.symmetric(Y))
False
References
==========
.. [1] https://en.wikipedia.org/wiki/Symmetric_matrix
"""
# TODO: Add handlers to make these keys work with
# actual matrices and add more examples in the docstring.
name = 'symmetric'
handler = Dispatcher("SymmetricHandler", doc="Handler for Q.symmetric.")
class InvertiblePredicate(Predicate):
"""
Invertible matrix predicate.
Explanation
===========
``Q.invertible(x)`` is true iff ``x`` is an invertible matrix.
A square matrix is called invertible only if its determinant is 0.
Examples
========
>>> from sympy import Q, ask, MatrixSymbol
>>> X = MatrixSymbol('X', 2, 2)
>>> Y = MatrixSymbol('Y', 2, 3)
>>> Z = MatrixSymbol('Z', 2, 2)
>>> ask(Q.invertible(X*Y), Q.invertible(X))
False
>>> ask(Q.invertible(X*Z), Q.invertible(X) & Q.invertible(Z))
True
>>> ask(Q.invertible(X), Q.fullrank(X) & Q.square(X))
True
References
==========
.. [1] https://en.wikipedia.org/wiki/Invertible_matrix
"""
name = 'invertible'
handler = Dispatcher("InvertibleHandler", doc="Handler for Q.invertible.")
class OrthogonalPredicate(Predicate):
"""
Orthogonal matrix predicate.
Explanation
===========
``Q.orthogonal(x)`` is true iff ``x`` is an orthogonal matrix.
A square matrix ``M`` is an orthogonal matrix if it satisfies
``M^TM = MM^T = I`` where ``M^T`` is the transpose matrix of
``M`` and ``I`` is an identity matrix. Note that an orthogonal
matrix is necessarily invertible.
Examples
========
>>> from sympy import Q, ask, MatrixSymbol, Identity
>>> X = MatrixSymbol('X', 2, 2)
>>> Y = MatrixSymbol('Y', 2, 3)
>>> Z = MatrixSymbol('Z', 2, 2)
>>> ask(Q.orthogonal(Y))
False
>>> ask(Q.orthogonal(X*Z*X), Q.orthogonal(X) & Q.orthogonal(Z))
True
>>> ask(Q.orthogonal(Identity(3)))
True
>>> ask(Q.invertible(X), Q.orthogonal(X))
True
References
==========
.. [1] https://en.wikipedia.org/wiki/Orthogonal_matrix
"""
name = 'orthogonal'
handler = Dispatcher("OrthogonalHandler", doc="Handler for key 'orthogonal'.")
class UnitaryPredicate(Predicate):
"""
Unitary matrix predicate.
Explanation
===========
``Q.unitary(x)`` is true iff ``x`` is a unitary matrix.
Unitary matrix is an analogue to orthogonal matrix. A square
matrix ``M`` with complex elements is unitary if :math:``M^TM = MM^T= I``
where :math:``M^T`` is the conjugate transpose matrix of ``M``.
Examples
========
>>> from sympy import Q, ask, MatrixSymbol, Identity
>>> X = MatrixSymbol('X', 2, 2)
>>> Y = MatrixSymbol('Y', 2, 3)
>>> Z = MatrixSymbol('Z', 2, 2)
>>> ask(Q.unitary(Y))
False
>>> ask(Q.unitary(X*Z*X), Q.unitary(X) & Q.unitary(Z))
True
>>> ask(Q.unitary(Identity(3)))
True
References
==========
.. [1] https://en.wikipedia.org/wiki/Unitary_matrix
"""
name = 'unitary'
handler = Dispatcher("UnitaryHandler", doc="Handler for key 'unitary'.")
class FullRankPredicate(Predicate):
"""
Fullrank matrix predicate.
Explanation
===========
``Q.fullrank(x)`` is true iff ``x`` is a full rank matrix.
A matrix is full rank if all rows and columns of the matrix
are linearly independent. A square matrix is full rank iff
its determinant is nonzero.
Examples
========
>>> from sympy import Q, ask, MatrixSymbol, ZeroMatrix, Identity
>>> X = MatrixSymbol('X', 2, 2)
>>> ask(Q.fullrank(X.T), Q.fullrank(X))
True
>>> ask(Q.fullrank(ZeroMatrix(3, 3)))
False
>>> ask(Q.fullrank(Identity(3)))
True
"""
name = 'fullrank'
handler = Dispatcher("FullRankHandler", doc="Handler for key 'fullrank'.")
class PositiveDefinitePredicate(Predicate):
r"""
Positive definite matrix predicate.
Explanation
===========
If $M$ is a :math:`n \times n` symmetric real matrix, it is said
to be positive definite if :math:`Z^TMZ` is positive for
every non-zero column vector $Z$ of $n$ real numbers.
Examples
========
>>> from sympy import Q, ask, MatrixSymbol, Identity
>>> X = MatrixSymbol('X', 2, 2)
>>> Y = MatrixSymbol('Y', 2, 3)
>>> Z = MatrixSymbol('Z', 2, 2)
>>> ask(Q.positive_definite(Y))
False
>>> ask(Q.positive_definite(Identity(3)))
True
>>> ask(Q.positive_definite(X + Z), Q.positive_definite(X) &
... Q.positive_definite(Z))
True
References
==========
.. [1] https://en.wikipedia.org/wiki/Positive-definite_matrix
"""
name = "positive_definite"
handler = Dispatcher("PositiveDefiniteHandler", doc="Handler for key 'positive_definite'.")
class UpperTriangularPredicate(Predicate):
"""
Upper triangular matrix predicate.
Explanation
===========
A matrix $M$ is called upper triangular matrix if :math:`M_{ij}=0`
for :math:`i<j`.
Examples
========
>>> from sympy import Q, ask, ZeroMatrix, Identity
>>> ask(Q.upper_triangular(Identity(3)))
True
>>> ask(Q.upper_triangular(ZeroMatrix(3, 3)))
True
References
==========
.. [1] https://mathworld.wolfram.com/UpperTriangularMatrix.html
"""
name = "upper_triangular"
handler = Dispatcher("UpperTriangularHandler", doc="Handler for key 'upper_triangular'.")
class LowerTriangularPredicate(Predicate):
"""
Lower triangular matrix predicate.
Explanation
===========
A matrix $M$ is called lower triangular matrix if :math:`M_{ij}=0`
for :math:`i>j`.
Examples
========
>>> from sympy import Q, ask, ZeroMatrix, Identity
>>> ask(Q.lower_triangular(Identity(3)))
True
>>> ask(Q.lower_triangular(ZeroMatrix(3, 3)))
True
References
==========
.. [1] https://mathworld.wolfram.com/LowerTriangularMatrix.html
"""
name = "lower_triangular"
handler = Dispatcher("LowerTriangularHandler", doc="Handler for key 'lower_triangular'.")
class DiagonalPredicate(Predicate):
"""
Diagonal matrix predicate.
Explanation
===========
``Q.diagonal(x)`` is true iff ``x`` is a diagonal matrix. A diagonal
matrix is a matrix in which the entries outside the main diagonal
are all zero.
Examples
========
>>> from sympy import Q, ask, MatrixSymbol, ZeroMatrix
>>> X = MatrixSymbol('X', 2, 2)
>>> ask(Q.diagonal(ZeroMatrix(3, 3)))
True
>>> ask(Q.diagonal(X), Q.lower_triangular(X) &
... Q.upper_triangular(X))
True
References
==========
.. [1] https://en.wikipedia.org/wiki/Diagonal_matrix
"""
name = "diagonal"
handler = Dispatcher("DiagonalHandler", doc="Handler for key 'diagonal'.")
class IntegerElementsPredicate(Predicate):
"""
Integer elements matrix predicate.
Explanation
===========
``Q.integer_elements(x)`` is true iff all the elements of ``x``
are integers.
Examples
========
>>> from sympy import Q, ask, MatrixSymbol
>>> X = MatrixSymbol('X', 4, 4)
>>> ask(Q.integer(X[1, 2]), Q.integer_elements(X))
True
"""
name = "integer_elements"
handler = Dispatcher("IntegerElementsHandler", doc="Handler for key 'integer_elements'.")
class RealElementsPredicate(Predicate):
"""
Real elements matrix predicate.
Explanation
===========
``Q.real_elements(x)`` is true iff all the elements of ``x``
are real numbers.
Examples
========
>>> from sympy import Q, ask, MatrixSymbol
>>> X = MatrixSymbol('X', 4, 4)
>>> ask(Q.real(X[1, 2]), Q.real_elements(X))
True
"""
name = "real_elements"
handler = Dispatcher("RealElementsHandler", doc="Handler for key 'real_elements'.")
class ComplexElementsPredicate(Predicate):
"""
Complex elements matrix predicate.
Explanation
===========
``Q.complex_elements(x)`` is true iff all the elements of ``x``
are complex numbers.
Examples
========
>>> from sympy import Q, ask, MatrixSymbol
>>> X = MatrixSymbol('X', 4, 4)
>>> ask(Q.complex(X[1, 2]), Q.complex_elements(X))
True
>>> ask(Q.complex_elements(X), Q.integer_elements(X))
True
"""
name = "complex_elements"
handler = Dispatcher("ComplexElementsHandler", doc="Handler for key 'complex_elements'.")
class SingularPredicate(Predicate):
"""
Singular matrix predicate.
A matrix is singular iff the value of its determinant is 0.
Examples
========
>>> from sympy import Q, ask, MatrixSymbol
>>> X = MatrixSymbol('X', 4, 4)
>>> ask(Q.singular(X), Q.invertible(X))
False
>>> ask(Q.singular(X), ~Q.invertible(X))
True
References
==========
.. [1] https://mathworld.wolfram.com/SingularMatrix.html
"""
name = "singular"
handler = Dispatcher("SingularHandler", doc="Predicate fore key 'singular'.")
class NormalPredicate(Predicate):
"""
Normal matrix predicate.
A matrix is normal if it commutes with its conjugate transpose.
Examples
========
>>> from sympy import Q, ask, MatrixSymbol
>>> X = MatrixSymbol('X', 4, 4)
>>> ask(Q.normal(X), Q.unitary(X))
True
References
==========
.. [1] https://en.wikipedia.org/wiki/Normal_matrix
"""
name = "normal"
handler = Dispatcher("NormalHandler", doc="Predicate fore key 'normal'.")
class TriangularPredicate(Predicate):
"""
Triangular matrix predicate.
Explanation
===========
``Q.triangular(X)`` is true if ``X`` is one that is either lower
triangular or upper triangular.
Examples
========
>>> from sympy import Q, ask, MatrixSymbol
>>> X = MatrixSymbol('X', 4, 4)
>>> ask(Q.triangular(X), Q.upper_triangular(X))
True
>>> ask(Q.triangular(X), Q.lower_triangular(X))
True
References
==========
.. [1] https://en.wikipedia.org/wiki/Triangular_matrix
"""
name = "triangular"
handler = Dispatcher("TriangularHandler", doc="Predicate fore key 'triangular'.")
class UnitTriangularPredicate(Predicate):
"""
Unit triangular matrix predicate.
Explanation
===========
A unit triangular matrix is a triangular matrix with 1s
on the diagonal.
Examples
========
>>> from sympy import Q, ask, MatrixSymbol
>>> X = MatrixSymbol('X', 4, 4)
>>> ask(Q.triangular(X), Q.unit_triangular(X))
True
"""
name = "unit_triangular"
handler = Dispatcher("UnitTriangularHandler", doc="Predicate fore key 'unit_triangular'.")
PK ]ZZZ�dn� � ' sympy/assumptions/predicates/ntheory.pyfrom sympy.assumptions import Predicate
from sympy.multipledispatch import Dispatcher
class PrimePredicate(Predicate):
"""
Prime number predicate.
Explanation
===========
``ask(Q.prime(x))`` is true iff ``x`` is a natural number greater
than 1 that has no positive divisors other than ``1`` and the
number itself.
Examples
========
>>> from sympy import Q, ask
>>> ask(Q.prime(0))
False
>>> ask(Q.prime(1))
False
>>> ask(Q.prime(2))
True
>>> ask(Q.prime(20))
False
>>> ask(Q.prime(-3))
False
"""
name = 'prime'
handler = Dispatcher(
"PrimeHandler",
doc=("Handler for key 'prime'. Test that an expression represents a prime"
" number. When the expression is an exact number, the result (when True)"
" is subject to the limitations of isprime() which is used to return the "
"result.")
)
class CompositePredicate(Predicate):
"""
Composite number predicate.
Explanation
===========
``ask(Q.composite(x))`` is true iff ``x`` is a positive integer and has
at least one positive divisor other than ``1`` and the number itself.
Examples
========
>>> from sympy import Q, ask
>>> ask(Q.composite(0))
False
>>> ask(Q.composite(1))
False
>>> ask(Q.composite(2))
False
>>> ask(Q.composite(20))
True
"""
name = 'composite'
handler = Dispatcher("CompositeHandler", doc="Handler for key 'composite'.")
class EvenPredicate(Predicate):
"""
Even number predicate.
Explanation
===========
``ask(Q.even(x))`` is true iff ``x`` belongs to the set of even
integers.
Examples
========
>>> from sympy import Q, ask, pi
>>> ask(Q.even(0))
True
>>> ask(Q.even(2))
True
>>> ask(Q.even(3))
False
>>> ask(Q.even(pi))
False
"""
name = 'even'
handler = Dispatcher("EvenHandler", doc="Handler for key 'even'.")
class OddPredicate(Predicate):
"""
Odd number predicate.
Explanation
===========
``ask(Q.odd(x))`` is true iff ``x`` belongs to the set of odd numbers.
Examples
========
>>> from sympy import Q, ask, pi
>>> ask(Q.odd(0))
False
>>> ask(Q.odd(2))
False
>>> ask(Q.odd(3))
True
>>> ask(Q.odd(pi))
False
"""
name = 'odd'
handler = Dispatcher(
"OddHandler",
doc=("Handler for key 'odd'. Test that an expression represents an odd"
" number.")
)
PK ]ZZZ�Nx�'% '% % sympy/assumptions/predicates/order.pyfrom sympy.assumptions import Predicate
from sympy.multipledispatch import Dispatcher
class NegativePredicate(Predicate):
r"""
Negative number predicate.
Explanation
===========
``Q.negative(x)`` is true iff ``x`` is a real number and :math:`x < 0`, that is,
it is in the interval :math:`(-\infty, 0)`. Note in particular that negative
infinity is not negative.
A few important facts about negative numbers:
- Note that ``Q.nonnegative`` and ``~Q.negative`` are *not* the same
thing. ``~Q.negative(x)`` simply means that ``x`` is not negative,
whereas ``Q.nonnegative(x)`` means that ``x`` is real and not
negative, i.e., ``Q.nonnegative(x)`` is logically equivalent to
``Q.zero(x) | Q.positive(x)``. So for example, ``~Q.negative(I)`` is
true, whereas ``Q.nonnegative(I)`` is false.
- See the documentation of ``Q.real`` for more information about
related facts.
Examples
========
>>> from sympy import Q, ask, symbols, I
>>> x = symbols('x')
>>> ask(Q.negative(x), Q.real(x) & ~Q.positive(x) & ~Q.zero(x))
True
>>> ask(Q.negative(-1))
True
>>> ask(Q.nonnegative(I))
False
>>> ask(~Q.negative(I))
True
"""
name = 'negative'
handler = Dispatcher(
"NegativeHandler",
doc=("Handler for Q.negative. Test that an expression is strictly less"
" than zero.")
)
class NonNegativePredicate(Predicate):
"""
Nonnegative real number predicate.
Explanation
===========
``ask(Q.nonnegative(x))`` is true iff ``x`` belongs to the set of
positive numbers including zero.
- Note that ``Q.nonnegative`` and ``~Q.negative`` are *not* the same
thing. ``~Q.negative(x)`` simply means that ``x`` is not negative,
whereas ``Q.nonnegative(x)`` means that ``x`` is real and not
negative, i.e., ``Q.nonnegative(x)`` is logically equivalent to
``Q.zero(x) | Q.positive(x)``. So for example, ``~Q.negative(I)`` is
true, whereas ``Q.nonnegative(I)`` is false.
Examples
========
>>> from sympy import Q, ask, I
>>> ask(Q.nonnegative(1))
True
>>> ask(Q.nonnegative(0))
True
>>> ask(Q.nonnegative(-1))
False
>>> ask(Q.nonnegative(I))
False
>>> ask(Q.nonnegative(-I))
False
"""
name = 'nonnegative'
handler = Dispatcher(
"NonNegativeHandler",
doc=("Handler for Q.nonnegative.")
)
class NonZeroPredicate(Predicate):
"""
Nonzero real number predicate.
Explanation
===========
``ask(Q.nonzero(x))`` is true iff ``x`` is real and ``x`` is not zero. Note in
particular that ``Q.nonzero(x)`` is false if ``x`` is not real. Use
``~Q.zero(x)`` if you want the negation of being zero without any real
assumptions.
A few important facts about nonzero numbers:
- ``Q.nonzero`` is logically equivalent to ``Q.positive | Q.negative``.
- See the documentation of ``Q.real`` for more information about
related facts.
Examples
========
>>> from sympy import Q, ask, symbols, I, oo
>>> x = symbols('x')
>>> print(ask(Q.nonzero(x), ~Q.zero(x)))
None
>>> ask(Q.nonzero(x), Q.positive(x))
True
>>> ask(Q.nonzero(x), Q.zero(x))
False
>>> ask(Q.nonzero(0))
False
>>> ask(Q.nonzero(I))
False
>>> ask(~Q.zero(I))
True
>>> ask(Q.nonzero(oo))
False
"""
name = 'nonzero'
handler = Dispatcher(
"NonZeroHandler",
doc=("Handler for key 'nonzero'. Test that an expression is not identically"
" zero.")
)
class ZeroPredicate(Predicate):
"""
Zero number predicate.
Explanation
===========
``ask(Q.zero(x))`` is true iff the value of ``x`` is zero.
Examples
========
>>> from sympy import ask, Q, oo, symbols
>>> x, y = symbols('x, y')
>>> ask(Q.zero(0))
True
>>> ask(Q.zero(1/oo))
True
>>> print(ask(Q.zero(0*oo)))
None
>>> ask(Q.zero(1))
False
>>> ask(Q.zero(x*y), Q.zero(x) | Q.zero(y))
True
"""
name = 'zero'
handler = Dispatcher(
"ZeroHandler",
doc="Handler for key 'zero'."
)
class NonPositivePredicate(Predicate):
"""
Nonpositive real number predicate.
Explanation
===========
``ask(Q.nonpositive(x))`` is true iff ``x`` belongs to the set of
negative numbers including zero.
- Note that ``Q.nonpositive`` and ``~Q.positive`` are *not* the same
thing. ``~Q.positive(x)`` simply means that ``x`` is not positive,
whereas ``Q.nonpositive(x)`` means that ``x`` is real and not
positive, i.e., ``Q.nonpositive(x)`` is logically equivalent to
`Q.negative(x) | Q.zero(x)``. So for example, ``~Q.positive(I)`` is
true, whereas ``Q.nonpositive(I)`` is false.
Examples
========
>>> from sympy import Q, ask, I
>>> ask(Q.nonpositive(-1))
True
>>> ask(Q.nonpositive(0))
True
>>> ask(Q.nonpositive(1))
False
>>> ask(Q.nonpositive(I))
False
>>> ask(Q.nonpositive(-I))
False
"""
name = 'nonpositive'
handler = Dispatcher(
"NonPositiveHandler",
doc="Handler for key 'nonpositive'."
)
class PositivePredicate(Predicate):
r"""
Positive real number predicate.
Explanation
===========
``Q.positive(x)`` is true iff ``x`` is real and `x > 0`, that is if ``x``
is in the interval `(0, \infty)`. In particular, infinity is not
positive.
A few important facts about positive numbers:
- Note that ``Q.nonpositive`` and ``~Q.positive`` are *not* the same
thing. ``~Q.positive(x)`` simply means that ``x`` is not positive,
whereas ``Q.nonpositive(x)`` means that ``x`` is real and not
positive, i.e., ``Q.nonpositive(x)`` is logically equivalent to
`Q.negative(x) | Q.zero(x)``. So for example, ``~Q.positive(I)`` is
true, whereas ``Q.nonpositive(I)`` is false.
- See the documentation of ``Q.real`` for more information about
related facts.
Examples
========
>>> from sympy import Q, ask, symbols, I
>>> x = symbols('x')
>>> ask(Q.positive(x), Q.real(x) & ~Q.negative(x) & ~Q.zero(x))
True
>>> ask(Q.positive(1))
True
>>> ask(Q.nonpositive(I))
False
>>> ask(~Q.positive(I))
True
"""
name = 'positive'
handler = Dispatcher(
"PositiveHandler",
doc=("Handler for key 'positive'. Test that an expression is strictly"
" greater than zero.")
)
class ExtendedPositivePredicate(Predicate):
r"""
Positive extended real number predicate.
Explanation
===========
``Q.extended_positive(x)`` is true iff ``x`` is extended real and
`x > 0`, that is if ``x`` is in the interval `(0, \infty]`.
Examples
========
>>> from sympy import ask, I, oo, Q
>>> ask(Q.extended_positive(1))
True
>>> ask(Q.extended_positive(oo))
True
>>> ask(Q.extended_positive(I))
False
"""
name = 'extended_positive'
handler = Dispatcher("ExtendedPositiveHandler")
class ExtendedNegativePredicate(Predicate):
r"""
Negative extended real number predicate.
Explanation
===========
``Q.extended_negative(x)`` is true iff ``x`` is extended real and
`x < 0`, that is if ``x`` is in the interval `[-\infty, 0)`.
Examples
========
>>> from sympy import ask, I, oo, Q
>>> ask(Q.extended_negative(-1))
True
>>> ask(Q.extended_negative(-oo))
True
>>> ask(Q.extended_negative(-I))
False
"""
name = 'extended_negative'
handler = Dispatcher("ExtendedNegativeHandler")
class ExtendedNonZeroPredicate(Predicate):
"""
Nonzero extended real number predicate.
Explanation
===========
``ask(Q.extended_nonzero(x))`` is true iff ``x`` is extended real and
``x`` is not zero.
Examples
========
>>> from sympy import ask, I, oo, Q
>>> ask(Q.extended_nonzero(-1))
True
>>> ask(Q.extended_nonzero(oo))
True
>>> ask(Q.extended_nonzero(I))
False
"""
name = 'extended_nonzero'
handler = Dispatcher("ExtendedNonZeroHandler")
class ExtendedNonPositivePredicate(Predicate):
"""
Nonpositive extended real number predicate.
Explanation
===========
``ask(Q.extended_nonpositive(x))`` is true iff ``x`` is extended real and
``x`` is not positive.
Examples
========
>>> from sympy import ask, I, oo, Q
>>> ask(Q.extended_nonpositive(-1))
True
>>> ask(Q.extended_nonpositive(oo))
False
>>> ask(Q.extended_nonpositive(0))
True
>>> ask(Q.extended_nonpositive(I))
False
"""
name = 'extended_nonpositive'
handler = Dispatcher("ExtendedNonPositiveHandler")
class ExtendedNonNegativePredicate(Predicate):
"""
Nonnegative extended real number predicate.
Explanation
===========
``ask(Q.extended_nonnegative(x))`` is true iff ``x`` is extended real and
``x`` is not negative.
Examples
========
>>> from sympy import ask, I, oo, Q
>>> ask(Q.extended_nonnegative(-1))
False
>>> ask(Q.extended_nonnegative(oo))
True
>>> ask(Q.extended_nonnegative(0))
True
>>> ask(Q.extended_nonnegative(I))
False
"""
name = 'extended_nonnegative'
handler = Dispatcher("ExtendedNonNegativeHandler")
PK ]ZZZ��c$ $ $ sympy/assumptions/predicates/sets.pyfrom sympy.assumptions import Predicate
from sympy.multipledispatch import Dispatcher
class IntegerPredicate(Predicate):
"""
Integer predicate.
Explanation
===========
``Q.integer(x)`` is true iff ``x`` belongs to the set of integer
numbers.
Examples
========
>>> from sympy import Q, ask, S
>>> ask(Q.integer(5))
True
>>> ask(Q.integer(S(1)/2))
False
References
==========
.. [1] https://en.wikipedia.org/wiki/Integer
"""
name = 'integer'
handler = Dispatcher(
"IntegerHandler",
doc=("Handler for Q.integer.\n\n"
"Test that an expression belongs to the field of integer numbers.")
)
class NonIntegerPredicate(Predicate):
"""
Non-integer extended real predicate.
"""
name = 'noninteger'
handler = Dispatcher(
"NonIntegerHandler",
doc=("Handler for Q.noninteger.\n\n"
"Test that an expression is a non-integer extended real number.")
)
class RationalPredicate(Predicate):
"""
Rational number predicate.
Explanation
===========
``Q.rational(x)`` is true iff ``x`` belongs to the set of
rational numbers.
Examples
========
>>> from sympy import ask, Q, pi, S
>>> ask(Q.rational(0))
True
>>> ask(Q.rational(S(1)/2))
True
>>> ask(Q.rational(pi))
False
References
==========
.. [1] https://en.wikipedia.org/wiki/Rational_number
"""
name = 'rational'
handler = Dispatcher(
"RationalHandler",
doc=("Handler for Q.rational.\n\n"
"Test that an expression belongs to the field of rational numbers.")
)
class IrrationalPredicate(Predicate):
"""
Irrational number predicate.
Explanation
===========
``Q.irrational(x)`` is true iff ``x`` is any real number that
cannot be expressed as a ratio of integers.
Examples
========
>>> from sympy import ask, Q, pi, S, I
>>> ask(Q.irrational(0))
False
>>> ask(Q.irrational(S(1)/2))
False
>>> ask(Q.irrational(pi))
True
>>> ask(Q.irrational(I))
False
References
==========
.. [1] https://en.wikipedia.org/wiki/Irrational_number
"""
name = 'irrational'
handler = Dispatcher(
"IrrationalHandler",
doc=("Handler for Q.irrational.\n\n"
"Test that an expression is irrational numbers.")
)
class RealPredicate(Predicate):
r"""
Real number predicate.
Explanation
===========
``Q.real(x)`` is true iff ``x`` is a real number, i.e., it is in the
interval `(-\infty, \infty)`. Note that, in particular the
infinities are not real. Use ``Q.extended_real`` if you want to
consider those as well.
A few important facts about reals:
- Every real number is positive, negative, or zero. Furthermore,
because these sets are pairwise disjoint, each real number is
exactly one of those three.
- Every real number is also complex.
- Every real number is finite.
- Every real number is either rational or irrational.
- Every real number is either algebraic or transcendental.
- The facts ``Q.negative``, ``Q.zero``, ``Q.positive``,
``Q.nonnegative``, ``Q.nonpositive``, ``Q.nonzero``,
``Q.integer``, ``Q.rational``, and ``Q.irrational`` all imply
``Q.real``, as do all facts that imply those facts.
- The facts ``Q.algebraic``, and ``Q.transcendental`` do not imply
``Q.real``; they imply ``Q.complex``. An algebraic or
transcendental number may or may not be real.
- The "non" facts (i.e., ``Q.nonnegative``, ``Q.nonzero``,
``Q.nonpositive`` and ``Q.noninteger``) are not equivalent to
not the fact, but rather, not the fact *and* ``Q.real``.
For example, ``Q.nonnegative`` means ``~Q.negative & Q.real``.
So for example, ``I`` is not nonnegative, nonzero, or
nonpositive.
Examples
========
>>> from sympy import Q, ask, symbols
>>> x = symbols('x')
>>> ask(Q.real(x), Q.positive(x))
True
>>> ask(Q.real(0))
True
References
==========
.. [1] https://en.wikipedia.org/wiki/Real_number
"""
name = 'real'
handler = Dispatcher(
"RealHandler",
doc=("Handler for Q.real.\n\n"
"Test that an expression belongs to the field of real numbers.")
)
class ExtendedRealPredicate(Predicate):
r"""
Extended real predicate.
Explanation
===========
``Q.extended_real(x)`` is true iff ``x`` is a real number or
`\{-\infty, \infty\}`.
See documentation of ``Q.real`` for more information about related
facts.
Examples
========
>>> from sympy import ask, Q, oo, I
>>> ask(Q.extended_real(1))
True
>>> ask(Q.extended_real(I))
False
>>> ask(Q.extended_real(oo))
True
"""
name = 'extended_real'
handler = Dispatcher(
"ExtendedRealHandler",
doc=("Handler for Q.extended_real.\n\n"
"Test that an expression belongs to the field of extended real\n"
"numbers, that is real numbers union {Infinity, -Infinity}.")
)
class HermitianPredicate(Predicate):
"""
Hermitian predicate.
Explanation
===========
``ask(Q.hermitian(x))`` is true iff ``x`` belongs to the set of
Hermitian operators.
References
==========
.. [1] https://mathworld.wolfram.com/HermitianOperator.html
"""
# TODO: Add examples
name = 'hermitian'
handler = Dispatcher(
"HermitianHandler",
doc=("Handler for Q.hermitian.\n\n"
"Test that an expression belongs to the field of Hermitian operators.")
)
class ComplexPredicate(Predicate):
"""
Complex number predicate.
Explanation
===========
``Q.complex(x)`` is true iff ``x`` belongs to the set of complex
numbers. Note that every complex number is finite.
Examples
========
>>> from sympy import Q, Symbol, ask, I, oo
>>> x = Symbol('x')
>>> ask(Q.complex(0))
True
>>> ask(Q.complex(2 + 3*I))
True
>>> ask(Q.complex(oo))
False
References
==========
.. [1] https://en.wikipedia.org/wiki/Complex_number
"""
name = 'complex'
handler = Dispatcher(
"ComplexHandler",
doc=("Handler for Q.complex.\n\n"
"Test that an expression belongs to the field of complex numbers.")
)
class ImaginaryPredicate(Predicate):
"""
Imaginary number predicate.
Explanation
===========
``Q.imaginary(x)`` is true iff ``x`` can be written as a real
number multiplied by the imaginary unit ``I``. Please note that ``0``
is not considered to be an imaginary number.
Examples
========
>>> from sympy import Q, ask, I
>>> ask(Q.imaginary(3*I))
True
>>> ask(Q.imaginary(2 + 3*I))
False
>>> ask(Q.imaginary(0))
False
References
==========
.. [1] https://en.wikipedia.org/wiki/Imaginary_number
"""
name = 'imaginary'
handler = Dispatcher(
"ImaginaryHandler",
doc=("Handler for Q.imaginary.\n\n"
"Test that an expression belongs to the field of imaginary numbers,\n"
"that is, numbers in the form x*I, where x is real.")
)
class AntihermitianPredicate(Predicate):
"""
Antihermitian predicate.
Explanation
===========
``Q.antihermitian(x)`` is true iff ``x`` belongs to the field of
antihermitian operators, i.e., operators in the form ``x*I``, where
``x`` is Hermitian.
References
==========
.. [1] https://mathworld.wolfram.com/HermitianOperator.html
"""
# TODO: Add examples
name = 'antihermitian'
handler = Dispatcher(
"AntiHermitianHandler",
doc=("Handler for Q.antihermitian.\n\n"
"Test that an expression belongs to the field of anti-Hermitian\n"
"operators, that is, operators in the form x*I, where x is Hermitian.")
)
class AlgebraicPredicate(Predicate):
r"""
Algebraic number predicate.
Explanation
===========
``Q.algebraic(x)`` is true iff ``x`` belongs to the set of
algebraic numbers. ``x`` is algebraic if there is some polynomial
in ``p(x)\in \mathbb\{Q\}[x]`` such that ``p(x) = 0``.
Examples
========
>>> from sympy import ask, Q, sqrt, I, pi
>>> ask(Q.algebraic(sqrt(2)))
True
>>> ask(Q.algebraic(I))
True
>>> ask(Q.algebraic(pi))
False
References
==========
.. [1] https://en.wikipedia.org/wiki/Algebraic_number
"""
name = 'algebraic'
AlgebraicHandler = Dispatcher(
"AlgebraicHandler",
doc="""Handler for Q.algebraic key."""
)
class TranscendentalPredicate(Predicate):
"""
Transcedental number predicate.
Explanation
===========
``Q.transcendental(x)`` is true iff ``x`` belongs to the set of
transcendental numbers. A transcendental number is a real
or complex number that is not algebraic.
"""
# TODO: Add examples
name = 'transcendental'
handler = Dispatcher(
"Transcendental",
doc="""Handler for Q.transcendental key."""
)
PK ]ZZZ:�� & sympy/assumptions/relation/__init__.py"""
A module to implement finitary relations [1] as predicate.
References
==========
.. [1] https://en.wikipedia.org/wiki/Finitary_relation
"""
__all__ = ['BinaryRelation', 'AppliedBinaryRelation']
from .binrel import BinaryRelation, AppliedBinaryRelation
PK ]ZZZaSA � � $ sympy/assumptions/relation/binrel.py"""
General binary relations.
"""
from typing import Optional
from sympy.core.singleton import S
from sympy.assumptions import AppliedPredicate, ask, Predicate, Q # type: ignore
from sympy.core.kind import BooleanKind
from sympy.core.relational import Eq, Ne, Gt, Lt, Ge, Le
from sympy.logic.boolalg import conjuncts, Not
__all__ = ["BinaryRelation", "AppliedBinaryRelation"]
class BinaryRelation(Predicate):
"""
Base class for all binary relational predicates.
Explanation
===========
Binary relation takes two arguments and returns ``AppliedBinaryRelation``
instance. To evaluate it to boolean value, use :obj:`~.ask()` or
:obj:`~.refine()` function.
You can add support for new types by registering the handler to dispatcher.
See :obj:`~.Predicate()` for more information about predicate dispatching.
Examples
========
Applying and evaluating to boolean value:
>>> from sympy import Q, ask, sin, cos
>>> from sympy.abc import x
>>> Q.eq(sin(x)**2+cos(x)**2, 1)
Q.eq(sin(x)**2 + cos(x)**2, 1)
>>> ask(_)
True
You can define a new binary relation by subclassing and dispatching.
Here, we define a relation $R$ such that $x R y$ returns true if
$x = y + 1$.
>>> from sympy import ask, Number, Q
>>> from sympy.assumptions import BinaryRelation
>>> class MyRel(BinaryRelation):
... name = "R"
... is_reflexive = False
>>> Q.R = MyRel()
>>> @Q.R.register(Number, Number)
... def _(n1, n2, assumptions):
... return ask(Q.zero(n1 - n2 - 1), assumptions)
>>> Q.R(2, 1)
Q.R(2, 1)
Now, we can use ``ask()`` to evaluate it to boolean value.
>>> ask(Q.R(2, 1))
True
>>> ask(Q.R(1, 2))
False
``Q.R`` returns ``False`` with minimum cost if two arguments have same
structure because it is antireflexive relation [1] by
``is_reflexive = False``.
>>> ask(Q.R(x, x))
False
References
==========
.. [1] https://en.wikipedia.org/wiki/Reflexive_relation
"""
is_reflexive: Optional[bool] = None
is_symmetric: Optional[bool] = None
def __call__(self, *args):
if not len(args) == 2:
raise ValueError("Binary relation takes two arguments, but got %s." % len(args))
return AppliedBinaryRelation(self, *args)
@property
def reversed(self):
if self.is_symmetric:
return self
return None
@property
def negated(self):
return None
def _compare_reflexive(self, lhs, rhs):
# quick exit for structurally same arguments
# do not check != here because it cannot catch the
# equivalent arguments with different structures.
# reflexivity does not hold to NaN
if lhs is S.NaN or rhs is S.NaN:
return None
reflexive = self.is_reflexive
if reflexive is None:
pass
elif reflexive and (lhs == rhs):
return True
elif not reflexive and (lhs == rhs):
return False
return None
def eval(self, args, assumptions=True):
# quick exit for structurally same arguments
ret = self._compare_reflexive(*args)
if ret is not None:
return ret
# don't perform simplify on args here. (done by AppliedBinaryRelation._eval_ask)
# evaluate by multipledispatch
lhs, rhs = args
ret = self.handler(lhs, rhs, assumptions=assumptions)
if ret is not None:
return ret
# check reversed order if the relation is reflexive
if self.is_reflexive:
types = (type(lhs), type(rhs))
if self.handler.dispatch(*types) is not self.handler.dispatch(*reversed(types)):
ret = self.handler(rhs, lhs, assumptions=assumptions)
return ret
class AppliedBinaryRelation(AppliedPredicate):
"""
The class of expressions resulting from applying ``BinaryRelation``
to the arguments.
"""
@property
def lhs(self):
"""The left-hand side of the relation."""
return self.arguments[0]
@property
def rhs(self):
"""The right-hand side of the relation."""
return self.arguments[1]
@property
def reversed(self):
"""
Try to return the relationship with sides reversed.
"""
revfunc = self.function.reversed
if revfunc is None:
return self
return revfunc(self.rhs, self.lhs)
@property
def reversedsign(self):
"""
Try to return the relationship with signs reversed.
"""
revfunc = self.function.reversed
if revfunc is None:
return self
if not any(side.kind is BooleanKind for side in self.arguments):
return revfunc(-self.lhs, -self.rhs)
return self
@property
def negated(self):
neg_rel = self.function.negated
if neg_rel is None:
return Not(self, evaluate=False)
return neg_rel(*self.arguments)
def _eval_ask(self, assumptions):
conj_assumps = set()
binrelpreds = {Eq: Q.eq, Ne: Q.ne, Gt: Q.gt, Lt: Q.lt, Ge: Q.ge, Le: Q.le}
for a in conjuncts(assumptions):
if a.func in binrelpreds:
conj_assumps.add(binrelpreds[type(a)](*a.args))
else:
conj_assumps.add(a)
# After CNF in assumptions module is modified to take polyadic
# predicate, this will be removed
if any(rel in conj_assumps for rel in (self, self.reversed)):
return True
neg_rels = (self.negated, self.reversed.negated, Not(self, evaluate=False),
Not(self.reversed, evaluate=False))
if any(rel in conj_assumps for rel in neg_rels):
return False
# evaluation using multipledispatching
ret = self.function.eval(self.arguments, assumptions)
if ret is not None:
return ret
# simplify the args and try again
args = tuple(a.simplify() for a in self.arguments)
return self.function.eval(args, assumptions)
def __bool__(self):
ret = ask(self)
if ret is None:
raise TypeError("Cannot determine truth value of %s" % self)
return ret
PK ]ZZZ{�D� � & sympy/assumptions/relation/equality.py"""
Module for mathematical equality [1] and inequalities [2].
The purpose of this module is to provide the instances which represent the
binary predicates in order to combine the relationals into logical inference
system. Objects such as ``Q.eq``, ``Q.lt`` should remain internal to
assumptions module, and user must use the classes such as :obj:`~.Eq()`,
:obj:`~.Lt()` instead to construct the relational expressions.
References
==========
.. [1] https://en.wikipedia.org/wiki/Equality_(mathematics)
.. [2] https://en.wikipedia.org/wiki/Inequality_(mathematics)
"""
from sympy.assumptions import Q
from sympy.core.relational import is_eq, is_neq, is_gt, is_ge, is_lt, is_le
from .binrel import BinaryRelation
__all__ = ['EqualityPredicate', 'UnequalityPredicate', 'StrictGreaterThanPredicate',
'GreaterThanPredicate', 'StrictLessThanPredicate', 'LessThanPredicate']
class EqualityPredicate(BinaryRelation):
"""
Binary predicate for $=$.
The purpose of this class is to provide the instance which represent
the equality predicate in order to allow the logical inference.
This class must remain internal to assumptions module and user must
use :obj:`~.Eq()` instead to construct the equality expression.
Evaluating this predicate to ``True`` or ``False`` is done by
:func:`~.core.relational.is_eq`
Examples
========
>>> from sympy import ask, Q
>>> Q.eq(0, 0)
Q.eq(0, 0)
>>> ask(_)
True
See Also
========
sympy.core.relational.Eq
"""
is_reflexive = True
is_symmetric = True
name = 'eq'
handler = None # Do not allow dispatching by this predicate
@property
def negated(self):
return Q.ne
def eval(self, args, assumptions=True):
if assumptions == True:
# default assumptions for is_eq is None
assumptions = None
return is_eq(*args, assumptions)
class UnequalityPredicate(BinaryRelation):
r"""
Binary predicate for $\neq$.
The purpose of this class is to provide the instance which represent
the inequation predicate in order to allow the logical inference.
This class must remain internal to assumptions module and user must
use :obj:`~.Ne()` instead to construct the inequation expression.
Evaluating this predicate to ``True`` or ``False`` is done by
:func:`~.core.relational.is_neq`
Examples
========
>>> from sympy import ask, Q
>>> Q.ne(0, 0)
Q.ne(0, 0)
>>> ask(_)
False
See Also
========
sympy.core.relational.Ne
"""
is_reflexive = False
is_symmetric = True
name = 'ne'
handler = None
@property
def negated(self):
return Q.eq
def eval(self, args, assumptions=True):
if assumptions == True:
# default assumptions for is_neq is None
assumptions = None
return is_neq(*args, assumptions)
class StrictGreaterThanPredicate(BinaryRelation):
"""
Binary predicate for $>$.
The purpose of this class is to provide the instance which represent
the ">" predicate in order to allow the logical inference.
This class must remain internal to assumptions module and user must
use :obj:`~.Gt()` instead to construct the equality expression.
Evaluating this predicate to ``True`` or ``False`` is done by
:func:`~.core.relational.is_gt`
Examples
========
>>> from sympy import ask, Q
>>> Q.gt(0, 0)
Q.gt(0, 0)
>>> ask(_)
False
See Also
========
sympy.core.relational.Gt
"""
is_reflexive = False
is_symmetric = False
name = 'gt'
handler = None
@property
def reversed(self):
return Q.lt
@property
def negated(self):
return Q.le
def eval(self, args, assumptions=True):
if assumptions == True:
# default assumptions for is_gt is None
assumptions = None
return is_gt(*args, assumptions)
class GreaterThanPredicate(BinaryRelation):
"""
Binary predicate for $>=$.
The purpose of this class is to provide the instance which represent
the ">=" predicate in order to allow the logical inference.
This class must remain internal to assumptions module and user must
use :obj:`~.Ge()` instead to construct the equality expression.
Evaluating this predicate to ``True`` or ``False`` is done by
:func:`~.core.relational.is_ge`
Examples
========
>>> from sympy import ask, Q
>>> Q.ge(0, 0)
Q.ge(0, 0)
>>> ask(_)
True
See Also
========
sympy.core.relational.Ge
"""
is_reflexive = True
is_symmetric = False
name = 'ge'
handler = None
@property
def reversed(self):
return Q.le
@property
def negated(self):
return Q.lt
def eval(self, args, assumptions=True):
if assumptions == True:
# default assumptions for is_ge is None
assumptions = None
return is_ge(*args, assumptions)
class StrictLessThanPredicate(BinaryRelation):
"""
Binary predicate for $<$.
The purpose of this class is to provide the instance which represent
the "<" predicate in order to allow the logical inference.
This class must remain internal to assumptions module and user must
use :obj:`~.Lt()` instead to construct the equality expression.
Evaluating this predicate to ``True`` or ``False`` is done by
:func:`~.core.relational.is_lt`
Examples
========
>>> from sympy import ask, Q
>>> Q.lt(0, 0)
Q.lt(0, 0)
>>> ask(_)
False
See Also
========
sympy.core.relational.Lt
"""
is_reflexive = False
is_symmetric = False
name = 'lt'
handler = None
@property
def reversed(self):
return Q.gt
@property
def negated(self):
return Q.ge
def eval(self, args, assumptions=True):
if assumptions == True:
# default assumptions for is_lt is None
assumptions = None
return is_lt(*args, assumptions)
class LessThanPredicate(BinaryRelation):
"""
Binary predicate for $<=$.
The purpose of this class is to provide the instance which represent
the "<=" predicate in order to allow the logical inference.
This class must remain internal to assumptions module and user must
use :obj:`~.Le()` instead to construct the equality expression.
Evaluating this predicate to ``True`` or ``False`` is done by
:func:`~.core.relational.is_le`
Examples
========
>>> from sympy import ask, Q
>>> Q.le(0, 0)
Q.le(0, 0)
>>> ask(_)
True
See Also
========
sympy.core.relational.Le
"""
is_reflexive = True
is_symmetric = False
name = 'le'
handler = None
@property
def reversed(self):
return Q.ge
@property
def negated(self):
return Q.gt
def eval(self, args, assumptions=True):
if assumptions == True:
# default assumptions for is_le is None
assumptions = None
return is_le(*args, assumptions)
PK ]ZZZ sympy/benchmarks/__init__.pyPK ]ZZZg��֩ � & sympy/benchmarks/bench_discrete_log.pyimport sys
from time import time
from sympy.ntheory.residue_ntheory import (discrete_log,
_discrete_log_trial_mul, _discrete_log_shanks_steps,
_discrete_log_pollard_rho, _discrete_log_pohlig_hellman)
# Cyclic group (Z/pZ)* with p prime, order p - 1 and generator g
data_set_1 = [
# p, p - 1, g
[191, 190, 19],
[46639, 46638, 6],
[14789363, 14789362, 2],
[4254225211, 4254225210, 2],
[432751500361, 432751500360, 7],
[158505390797053, 158505390797052, 2],
[6575202655312007, 6575202655312006, 5],
[8430573471995353769, 8430573471995353768, 3],
[3938471339744997827267, 3938471339744997827266, 2],
[875260951364705563393093, 875260951364705563393092, 5],
]
# Cyclic sub-groups of (Z/nZ)* with prime order p and generator g
# (n, p are primes and n = 2 * p + 1)
data_set_2 = [
# n, p, g
[227, 113, 3],
[2447, 1223, 2],
[24527, 12263, 2],
[245639, 122819, 2],
[2456747, 1228373, 3],
[24567899, 12283949, 3],
[245679023, 122839511, 2],
[2456791307, 1228395653, 3],
[24567913439, 12283956719, 2],
[245679135407, 122839567703, 2],
[2456791354763, 1228395677381, 3],
[24567913550903, 12283956775451, 2],
[245679135509519, 122839567754759, 2],
]
# Cyclic sub-groups of (Z/nZ)* with smooth order o and generator g
data_set_3 = [
# n, o, g
[2**118, 2**116, 3],
]
def bench_discrete_log(data_set, algo=None):
if algo is None:
f = discrete_log
elif algo == 'trial':
f = _discrete_log_trial_mul
elif algo == 'shanks':
f = _discrete_log_shanks_steps
elif algo == 'rho':
f = _discrete_log_pollard_rho
elif algo == 'ph':
f = _discrete_log_pohlig_hellman
else:
raise ValueError("Argument 'algo' should be one"
" of ('trial', 'shanks', 'rho' or 'ph')")
for i, data in enumerate(data_set):
for j, (n, p, g) in enumerate(data):
t = time()
l = f(n, pow(g, p - 1, n), g, p)
t = time() - t
print('[%02d-%03d] %15.10f' % (i, j, t))
assert l == p - 1
if __name__ == '__main__':
algo = sys.argv[1] \
if len(sys.argv) > 1 else None
data_set = [
data_set_1,
data_set_2,
data_set_3,
]
bench_discrete_log(data_set, algo)
PK ]ZZZ�5�Z- Z- # sympy/benchmarks/bench_meijerint.py# conceal the implicit import from the code quality tester
from sympy.core.numbers import (oo, pi)
from sympy.core.symbol import (Symbol, symbols)
from sympy.functions.elementary.exponential import exp
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.special.bessel import besseli
from sympy.functions.special.gamma_functions import gamma
from sympy.integrals.integrals import integrate
from sympy.integrals.transforms import (mellin_transform,
inverse_fourier_transform, inverse_mellin_transform,
laplace_transform, inverse_laplace_transform, fourier_transform)
LT = laplace_transform
FT = fourier_transform
MT = mellin_transform
IFT = inverse_fourier_transform
ILT = inverse_laplace_transform
IMT = inverse_mellin_transform
from sympy.abc import x, y
nu, beta, rho = symbols('nu beta rho')
apos, bpos, cpos, dpos, posk, p = symbols('a b c d k p', positive=True)
k = Symbol('k', real=True)
negk = Symbol('k', negative=True)
mu1, mu2 = symbols('mu1 mu2', real=True, nonzero=True, finite=True)
sigma1, sigma2 = symbols('sigma1 sigma2', real=True, nonzero=True,
finite=True, positive=True)
rate = Symbol('lambda', positive=True)
def normal(x, mu, sigma):
return 1/sqrt(2*pi*sigma**2)*exp(-(x - mu)**2/2/sigma**2)
def exponential(x, rate):
return rate*exp(-rate*x)
alpha, beta = symbols('alpha beta', positive=True)
betadist = x**(alpha - 1)*(1 + x)**(-alpha - beta)*gamma(alpha + beta) \
/gamma(alpha)/gamma(beta)
kint = Symbol('k', integer=True, positive=True)
chi = 2**(1 - kint/2)*x**(kint - 1)*exp(-x**2/2)/gamma(kint/2)
chisquared = 2**(-k/2)/gamma(k/2)*x**(k/2 - 1)*exp(-x/2)
dagum = apos*p/x*(x/bpos)**(apos*p)/(1 + x**apos/bpos**apos)**(p + 1)
d1, d2 = symbols('d1 d2', positive=True)
f = sqrt(((d1*x)**d1 * d2**d2)/(d1*x + d2)**(d1 + d2))/x \
/gamma(d1/2)/gamma(d2/2)*gamma((d1 + d2)/2)
nupos, sigmapos = symbols('nu sigma', positive=True)
rice = x/sigmapos**2*exp(-(x**2 + nupos**2)/2/sigmapos**2)*besseli(0, x*
nupos/sigmapos**2)
mu = Symbol('mu', real=True)
laplace = exp(-abs(x - mu)/bpos)/2/bpos
u = Symbol('u', polar=True)
tpos = Symbol('t', positive=True)
def E(expr):
integrate(expr*exponential(x, rate)*normal(y, mu1, sigma1),
(x, 0, oo), (y, -oo, oo), meijerg=True)
integrate(expr*exponential(x, rate)*normal(y, mu1, sigma1),
(y, -oo, oo), (x, 0, oo), meijerg=True)
bench = [
'MT(x**nu*Heaviside(x - 1), x, s)',
'MT(x**nu*Heaviside(1 - x), x, s)',
'MT((1-x)**(beta - 1)*Heaviside(1-x), x, s)',
'MT((x-1)**(beta - 1)*Heaviside(x-1), x, s)',
'MT((1+x)**(-rho), x, s)',
'MT(abs(1-x)**(-rho), x, s)',
'MT((1-x)**(beta-1)*Heaviside(1-x) + a*(x-1)**(beta-1)*Heaviside(x-1), x, s)',
'MT((x**a-b**a)/(x-b), x, s)',
'MT((x**a-bpos**a)/(x-bpos), x, s)',
'MT(exp(-x), x, s)',
'MT(exp(-1/x), x, s)',
'MT(log(x)**4*Heaviside(1-x), x, s)',
'MT(log(x)**3*Heaviside(x-1), x, s)',
'MT(log(x + 1), x, s)',
'MT(log(1/x + 1), x, s)',
'MT(log(abs(1 - x)), x, s)',
'MT(log(abs(1 - 1/x)), x, s)',
'MT(log(x)/(x+1), x, s)',
'MT(log(x)**2/(x+1), x, s)',
'MT(log(x)/(x+1)**2, x, s)',
'MT(erf(sqrt(x)), x, s)',
'MT(besselj(a, 2*sqrt(x)), x, s)',
'MT(sin(sqrt(x))*besselj(a, sqrt(x)), x, s)',
'MT(cos(sqrt(x))*besselj(a, sqrt(x)), x, s)',
'MT(besselj(a, sqrt(x))**2, x, s)',
'MT(besselj(a, sqrt(x))*besselj(-a, sqrt(x)), x, s)',
'MT(besselj(a - 1, sqrt(x))*besselj(a, sqrt(x)), x, s)',
'MT(besselj(a, sqrt(x))*besselj(b, sqrt(x)), x, s)',
'MT(besselj(a, sqrt(x))**2 + besselj(-a, sqrt(x))**2, x, s)',
'MT(bessely(a, 2*sqrt(x)), x, s)',
'MT(sin(sqrt(x))*bessely(a, sqrt(x)), x, s)',
'MT(cos(sqrt(x))*bessely(a, sqrt(x)), x, s)',
'MT(besselj(a, sqrt(x))*bessely(a, sqrt(x)), x, s)',
'MT(besselj(a, sqrt(x))*bessely(b, sqrt(x)), x, s)',
'MT(bessely(a, sqrt(x))**2, x, s)',
'MT(besselk(a, 2*sqrt(x)), x, s)',
'MT(besselj(a, 2*sqrt(2*sqrt(x)))*besselk(a, 2*sqrt(2*sqrt(x))), x, s)',
'MT(besseli(a, sqrt(x))*besselk(a, sqrt(x)), x, s)',
'MT(besseli(b, sqrt(x))*besselk(a, sqrt(x)), x, s)',
'MT(exp(-x/2)*besselk(a, x/2), x, s)',
# later: ILT, IMT
'LT((t-apos)**bpos*exp(-cpos*(t-apos))*Heaviside(t-apos), t, s)',
'LT(t**apos, t, s)',
'LT(Heaviside(t), t, s)',
'LT(Heaviside(t - apos), t, s)',
'LT(1 - exp(-apos*t), t, s)',
'LT((exp(2*t)-1)*exp(-bpos - t)*Heaviside(t)/2, t, s, noconds=True)',
'LT(exp(t), t, s)',
'LT(exp(2*t), t, s)',
'LT(exp(apos*t), t, s)',
'LT(log(t/apos), t, s)',
'LT(erf(t), t, s)',
'LT(sin(apos*t), t, s)',
'LT(cos(apos*t), t, s)',
'LT(exp(-apos*t)*sin(bpos*t), t, s)',
'LT(exp(-apos*t)*cos(bpos*t), t, s)',
'LT(besselj(0, t), t, s, noconds=True)',
'LT(besselj(1, t), t, s, noconds=True)',
'FT(Heaviside(1 - abs(2*apos*x)), x, k)',
'FT(Heaviside(1-abs(apos*x))*(1-abs(apos*x)), x, k)',
'FT(exp(-apos*x)*Heaviside(x), x, k)',
'IFT(1/(apos + 2*pi*I*x), x, posk, noconds=False)',
'IFT(1/(apos + 2*pi*I*x), x, -posk, noconds=False)',
'IFT(1/(apos + 2*pi*I*x), x, negk)',
'FT(x*exp(-apos*x)*Heaviside(x), x, k)',
'FT(exp(-apos*x)*sin(bpos*x)*Heaviside(x), x, k)',
'FT(exp(-apos*x**2), x, k)',
'IFT(sqrt(pi/apos)*exp(-(pi*k)**2/apos), k, x)',
'FT(exp(-apos*abs(x)), x, k)',
'integrate(normal(x, mu1, sigma1), (x, -oo, oo), meijerg=True)',
'integrate(x*normal(x, mu1, sigma1), (x, -oo, oo), meijerg=True)',
'integrate(x**2*normal(x, mu1, sigma1), (x, -oo, oo), meijerg=True)',
'integrate(x**3*normal(x, mu1, sigma1), (x, -oo, oo), meijerg=True)',
'integrate(normal(x, mu1, sigma1)*normal(y, mu2, sigma2),'
' (x, -oo, oo), (y, -oo, oo), meijerg=True)',
'integrate(x*normal(x, mu1, sigma1)*normal(y, mu2, sigma2),'
' (x, -oo, oo), (y, -oo, oo), meijerg=True)',
'integrate(y*normal(x, mu1, sigma1)*normal(y, mu2, sigma2),'
' (x, -oo, oo), (y, -oo, oo), meijerg=True)',
'integrate(x*y*normal(x, mu1, sigma1)*normal(y, mu2, sigma2),'
' (x, -oo, oo), (y, -oo, oo), meijerg=True)',
'integrate((x+y+1)*normal(x, mu1, sigma1)*normal(y, mu2, sigma2),'
' (x, -oo, oo), (y, -oo, oo), meijerg=True)',
'integrate((x+y-1)*normal(x, mu1, sigma1)*normal(y, mu2, sigma2),'
' (x, -oo, oo), (y, -oo, oo), meijerg=True)',
'integrate(x**2*normal(x, mu1, sigma1)*normal(y, mu2, sigma2),'
' (x, -oo, oo), (y, -oo, oo), meijerg=True)',
'integrate(y**2*normal(x, mu1, sigma1)*normal(y, mu2, sigma2),'
' (x, -oo, oo), (y, -oo, oo), meijerg=True)',
'integrate(exponential(x, rate), (x, 0, oo), meijerg=True)',
'integrate(x*exponential(x, rate), (x, 0, oo), meijerg=True)',
'integrate(x**2*exponential(x, rate), (x, 0, oo), meijerg=True)',
'E(1)',
'E(x*y)',
'E(x*y**2)',
'E((x+y+1)**2)',
'E(x+y+1)',
'E((x+y-1)**2)',
'integrate(betadist, (x, 0, oo), meijerg=True)',
'integrate(x*betadist, (x, 0, oo), meijerg=True)',
'integrate(x**2*betadist, (x, 0, oo), meijerg=True)',
'integrate(chi, (x, 0, oo), meijerg=True)',
'integrate(x*chi, (x, 0, oo), meijerg=True)',
'integrate(x**2*chi, (x, 0, oo), meijerg=True)',
'integrate(chisquared, (x, 0, oo), meijerg=True)',
'integrate(x*chisquared, (x, 0, oo), meijerg=True)',
'integrate(x**2*chisquared, (x, 0, oo), meijerg=True)',
'integrate(((x-k)/sqrt(2*k))**3*chisquared, (x, 0, oo), meijerg=True)',
'integrate(dagum, (x, 0, oo), meijerg=True)',
'integrate(x*dagum, (x, 0, oo), meijerg=True)',
'integrate(x**2*dagum, (x, 0, oo), meijerg=True)',
'integrate(f, (x, 0, oo), meijerg=True)',
'integrate(x*f, (x, 0, oo), meijerg=True)',
'integrate(x**2*f, (x, 0, oo), meijerg=True)',
'integrate(rice, (x, 0, oo), meijerg=True)',
'integrate(laplace, (x, -oo, oo), meijerg=True)',
'integrate(x*laplace, (x, -oo, oo), meijerg=True)',
'integrate(x**2*laplace, (x, -oo, oo), meijerg=True)',
'integrate(log(x) * x**(k-1) * exp(-x) / gamma(k), (x, 0, oo))',
'integrate(sin(z*x)*(x**2-1)**(-(y+S(1)/2)), (x, 1, oo), meijerg=True)',
'integrate(besselj(0,x)*besselj(1,x)*exp(-x**2), (x, 0, oo), meijerg=True)',
'integrate(besselj(0,x)*besselj(1,x)*besselk(0,x), (x, 0, oo), meijerg=True)',
'integrate(besselj(0,x)*besselj(1,x)*exp(-x**2), (x, 0, oo), meijerg=True)',
'integrate(besselj(a,x)*besselj(b,x)/x, (x,0,oo), meijerg=True)',
'hyperexpand(meijerg((-s - a/2 + 1, -s + a/2 + 1), (-a/2 - S(1)/2, -s + a/2 + S(3)/2), (a/2, -a/2), (-a/2 - S(1)/2, -s + a/2 + S(3)/2), 1))',
"gammasimp(S('2**(2*s)*(-pi*gamma(-a + 1)*gamma(a + 1)*gamma(-a - s + 1)*gamma(-a + s - 1/2)*gamma(a - s + 3/2)*gamma(a + s + 1)/(a*(a + s)) - gamma(-a - 1/2)*gamma(-a + 1)*gamma(a + 1)*gamma(a + 3/2)*gamma(-s + 3/2)*gamma(s - 1/2)*gamma(-a + s + 1)*gamma(a - s + 1)/(a*(-a + s)))*gamma(-2*s + 1)*gamma(s + 1)/(pi*s*gamma(-a - 1/2)*gamma(a + 3/2)*gamma(-s + 1)*gamma(-s + 3/2)*gamma(s - 1/2)*gamma(-a - s + 1)*gamma(-a + s - 1/2)*gamma(a - s + 1)*gamma(a - s + 3/2))'))",
'mellin_transform(E1(x), x, s)',
'inverse_mellin_transform(gamma(s)/s, s, x, (0, oo))',
'mellin_transform(expint(a, x), x, s)',
'mellin_transform(Si(x), x, s)',
'inverse_mellin_transform(-2**s*sqrt(pi)*gamma((s + 1)/2)/(2*s*gamma(-s/2 + 1)), s, x, (-1, 0))',
'mellin_transform(Ci(sqrt(x)), x, s)',
'inverse_mellin_transform(-4**s*sqrt(pi)*gamma(s)/(2*s*gamma(-s + S(1)/2)),s, u, (0, 1))',
'laplace_transform(Ci(x), x, s)',
'laplace_transform(expint(a, x), x, s)',
'laplace_transform(expint(1, x), x, s)',
'laplace_transform(expint(2, x), x, s)',
'inverse_laplace_transform(-log(1 + s**2)/2/s, s, u)',
'inverse_laplace_transform(log(s + 1)/s, s, x)',
'inverse_laplace_transform((s - log(s + 1))/s**2, s, x)',
'laplace_transform(Chi(x), x, s)',
'laplace_transform(Shi(x), x, s)',
'integrate(exp(-z*x)/x, (x, 1, oo), meijerg=True, conds="none")',
'integrate(exp(-z*x)/x**2, (x, 1, oo), meijerg=True, conds="none")',
'integrate(exp(-z*x)/x**3, (x, 1, oo), meijerg=True,conds="none")',
'integrate(-cos(x)/x, (x, tpos, oo), meijerg=True)',
'integrate(-sin(x)/x, (x, tpos, oo), meijerg=True)',
'integrate(sin(x)/x, (x, 0, z), meijerg=True)',
'integrate(sinh(x)/x, (x, 0, z), meijerg=True)',
'integrate(exp(-x)/x, x, meijerg=True)',
'integrate(exp(-x)/x**2, x, meijerg=True)',
'integrate(cos(u)/u, u, meijerg=True)',
'integrate(cosh(u)/u, u, meijerg=True)',
'integrate(expint(1, x), x, meijerg=True)',
'integrate(expint(2, x), x, meijerg=True)',
'integrate(Si(x), x, meijerg=True)',
'integrate(Ci(u), u, meijerg=True)',
'integrate(Shi(x), x, meijerg=True)',
'integrate(Chi(u), u, meijerg=True)',
'integrate(Si(x)*exp(-x), (x, 0, oo), meijerg=True)',
'integrate(expint(1, x)*sin(x), (x, 0, oo), meijerg=True)'
]
from time import time
from sympy.core.cache import clear_cache
import sys
timings = []
if __name__ == '__main__':
for n, string in enumerate(bench):
clear_cache()
_t = time()
exec(string)
_t = time() - _t
timings += [(_t, string)]
sys.stdout.write('.')
sys.stdout.flush()
if n % (len(bench) // 10) == 0:
sys.stdout.write('%s' % (10*n // len(bench)))
print()
timings.sort(key=lambda x: -x[0])
for ti, string in timings:
print('%.2fs %s' % (ti, string))
PK ]ZZZ^IF[� � " sympy/benchmarks/bench_symbench.py#!/usr/bin/env python
from sympy.core.random import random
from sympy.core.numbers import (I, Integer, pi)
from sympy.core.symbol import Symbol
from sympy.core.sympify import sympify
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.elementary.trigonometric import sin
from sympy.polys.polytools import factor
from sympy.simplify.simplify import simplify
from sympy.abc import x, y, z
from timeit import default_timer as clock
def bench_R1():
"real(f(f(f(f(f(f(f(f(f(f(i/2)))))))))))"
def f(z):
return sqrt(Integer(1)/3)*z**2 + I/3
f(f(f(f(f(f(f(f(f(f(I/2)))))))))).as_real_imag()[0]
def bench_R2():
"Hermite polynomial hermite(15, y)"
def hermite(n, y):
if n == 1:
return 2*y
if n == 0:
return 1
return (2*y*hermite(n - 1, y) - 2*(n - 1)*hermite(n - 2, y)).expand()
hermite(15, y)
def bench_R3():
"a = [bool(f==f) for _ in range(10)]"
f = x + y + z
[bool(f == f) for _ in range(10)]
def bench_R4():
# we don't have Tuples
pass
def bench_R5():
"blowup(L, 8); L=uniq(L)"
def blowup(L, n):
for i in range(n):
L.append( (L[i] + L[i + 1]) * L[i + 2] )
def uniq(x):
v = set(x)
return v
L = [x, y, z]
blowup(L, 8)
L = uniq(L)
def bench_R6():
"sum(simplify((x+sin(i))/x+(x-sin(i))/x) for i in range(100))"
sum(simplify((x + sin(i))/x + (x - sin(i))/x) for i in range(100))
def bench_R7():
"[f.subs(x, random()) for _ in range(10**4)]"
f = x**24 + 34*x**12 + 45*x**3 + 9*x**18 + 34*x**10 + 32*x**21
[f.subs(x, random()) for _ in range(10**4)]
def bench_R8():
"right(x^2,0,5,10^4)"
def right(f, a, b, n):
a = sympify(a)
b = sympify(b)
n = sympify(n)
x = f.atoms(Symbol).pop()
Deltax = (b - a)/n
c = a
est = 0
for i in range(n):
c += Deltax
est += f.subs(x, c)
return est*Deltax
right(x**2, 0, 5, 10**4)
def _bench_R9():
"factor(x^20 - pi^5*y^20)"
factor(x**20 - pi**5*y**20)
def bench_R10():
"v = [-pi,-pi+1/10..,pi]"
def srange(min, max, step):
v = [min]
while (max - v[-1]).evalf() > 0:
v.append(v[-1] + step)
return v[:-1]
srange(-pi, pi, sympify(1)/10)
def bench_R11():
"a = [random() + random()*I for w in [0..1000]]"
[random() + random()*I for w in range(1000)]
def bench_S1():
"e=(x+y+z+1)**7;f=e*(e+1);f.expand()"
e = (x + y + z + 1)**7
f = e*(e + 1)
f.expand()
if __name__ == '__main__':
benchmarks = [
bench_R1,
bench_R2,
bench_R3,
bench_R5,
bench_R6,
bench_R7,
bench_R8,
#_bench_R9,
bench_R10,
bench_R11,
#bench_S1,
]
report = []
for b in benchmarks:
t = clock()
b()
t = clock() - t
print("%s%65s: %f" % (b.__name__, b.__doc__, t))
PK ]ZZZ3�~p< < sympy/calculus/__init__.py"""Calculus-related methods."""
from .euler import euler_equations
from .singularities import (singularities, is_increasing,
is_strictly_increasing, is_decreasing,
is_strictly_decreasing, is_monotonic)
from .finite_diff import finite_diff_weights, apply_finite_diff, differentiate_finite
from .util import (periodicity, not_empty_in, is_convex,
stationary_points, minimum, maximum)
from .accumulationbounds import AccumBounds
__all__ = [
'euler_equations',
'singularities', 'is_increasing',
'is_strictly_increasing', 'is_decreasing',
'is_strictly_decreasing', 'is_monotonic',
'finite_diff_weights', 'apply_finite_diff', 'differentiate_finite',
'periodicity', 'not_empty_in', 'is_convex', 'stationary_points',
'minimum', 'maximum',
'AccumBounds'
]
PK ]ZZZJ����o �o $ sympy/calculus/accumulationbounds.pyfrom sympy.core import Add, Mul, Pow, S
from sympy.core.basic import Basic
from sympy.core.expr import Expr
from sympy.core.numbers import _sympifyit, oo, zoo
from sympy.core.relational import is_le, is_lt, is_ge, is_gt
from sympy.core.sympify import _sympify
from sympy.functions.elementary.miscellaneous import Min, Max
from sympy.logic.boolalg import And
from sympy.multipledispatch import dispatch
from sympy.series.order import Order
from sympy.sets.sets import FiniteSet
class AccumulationBounds(Expr):
r"""An accumulation bounds.
# Note AccumulationBounds has an alias: AccumBounds
AccumulationBounds represent an interval `[a, b]`, which is always closed
at the ends. Here `a` and `b` can be any value from extended real numbers.
The intended meaning of AccummulationBounds is to give an approximate
location of the accumulation points of a real function at a limit point.
Let `a` and `b` be reals such that `a \le b`.
`\left\langle a, b\right\rangle = \{x \in \mathbb{R} \mid a \le x \le b\}`
`\left\langle -\infty, b\right\rangle = \{x \in \mathbb{R} \mid x \le b\} \cup \{-\infty, \infty\}`
`\left\langle a, \infty \right\rangle = \{x \in \mathbb{R} \mid a \le x\} \cup \{-\infty, \infty\}`
`\left\langle -\infty, \infty \right\rangle = \mathbb{R} \cup \{-\infty, \infty\}`
``oo`` and ``-oo`` are added to the second and third definition respectively,
since if either ``-oo`` or ``oo`` is an argument, then the other one should
be included (though not as an end point). This is forced, since we have,
for example, ``1/AccumBounds(0, 1) = AccumBounds(1, oo)``, and the limit at
`0` is not one-sided. As `x` tends to `0-`, then `1/x \rightarrow -\infty`, so `-\infty`
should be interpreted as belonging to ``AccumBounds(1, oo)`` though it need
not appear explicitly.
In many cases it suffices to know that the limit set is bounded.
However, in some other cases more exact information could be useful.
For example, all accumulation values of `\cos(x) + 1` are non-negative.
(``AccumBounds(-1, 1) + 1 = AccumBounds(0, 2)``)
A AccumulationBounds object is defined to be real AccumulationBounds,
if its end points are finite reals.
Let `X`, `Y` be real AccumulationBounds, then their sum, difference,
product are defined to be the following sets:
`X + Y = \{ x+y \mid x \in X \cap y \in Y\}`
`X - Y = \{ x-y \mid x \in X \cap y \in Y\}`
`X \times Y = \{ x \times y \mid x \in X \cap y \in Y\}`
When an AccumBounds is raised to a negative power, if 0 is contained
between the bounds then an infinite range is returned, otherwise if an
endpoint is 0 then a semi-infinite range with consistent sign will be returned.
AccumBounds in expressions behave a lot like Intervals but the
semantics are not necessarily the same. Division (or exponentiation
to a negative integer power) could be handled with *intervals* by
returning a union of the results obtained after splitting the
bounds between negatives and positives, but that is not done with
AccumBounds. In addition, bounds are assumed to be independent of
each other; if the same bound is used in more than one place in an
expression, the result may not be the supremum or infimum of the
expression (see below). Finally, when a boundary is ``1``,
exponentiation to the power of ``oo`` yields ``oo``, neither
``1`` nor ``nan``.
Examples
========
>>> from sympy import AccumBounds, sin, exp, log, pi, E, S, oo
>>> from sympy.abc import x
>>> AccumBounds(0, 1) + AccumBounds(1, 2)
AccumBounds(1, 3)
>>> AccumBounds(0, 1) - AccumBounds(0, 2)
AccumBounds(-2, 1)
>>> AccumBounds(-2, 3)*AccumBounds(-1, 1)
AccumBounds(-3, 3)
>>> AccumBounds(1, 2)*AccumBounds(3, 5)
AccumBounds(3, 10)
The exponentiation of AccumulationBounds is defined
as follows:
If 0 does not belong to `X` or `n > 0` then
`X^n = \{ x^n \mid x \in X\}`
>>> AccumBounds(1, 4)**(S(1)/2)
AccumBounds(1, 2)
otherwise, an infinite or semi-infinite result is obtained:
>>> 1/AccumBounds(-1, 1)
AccumBounds(-oo, oo)
>>> 1/AccumBounds(0, 2)
AccumBounds(1/2, oo)
>>> 1/AccumBounds(-oo, 0)
AccumBounds(-oo, 0)
A boundary of 1 will always generate all nonnegatives:
>>> AccumBounds(1, 2)**oo
AccumBounds(0, oo)
>>> AccumBounds(0, 1)**oo
AccumBounds(0, oo)
If the exponent is itself an AccumulationBounds or is not an
integer then unevaluated results will be returned unless the base
values are positive:
>>> AccumBounds(2, 3)**AccumBounds(-1, 2)
AccumBounds(1/3, 9)
>>> AccumBounds(-2, 3)**AccumBounds(-1, 2)
AccumBounds(-2, 3)**AccumBounds(-1, 2)
>>> AccumBounds(-2, -1)**(S(1)/2)
sqrt(AccumBounds(-2, -1))
Note: `\left\langle a, b\right\rangle^2` is not same as `\left\langle a, b\right\rangle \times \left\langle a, b\right\rangle`
>>> AccumBounds(-1, 1)**2
AccumBounds(0, 1)
>>> AccumBounds(1, 3) < 4
True
>>> AccumBounds(1, 3) < -1
False
Some elementary functions can also take AccumulationBounds as input.
A function `f` evaluated for some real AccumulationBounds `\left\langle a, b \right\rangle`
is defined as `f(\left\langle a, b\right\rangle) = \{ f(x) \mid a \le x \le b \}`
>>> sin(AccumBounds(pi/6, pi/3))
AccumBounds(1/2, sqrt(3)/2)
>>> exp(AccumBounds(0, 1))
AccumBounds(1, E)
>>> log(AccumBounds(1, E))
AccumBounds(0, 1)
Some symbol in an expression can be substituted for a AccumulationBounds
object. But it does not necessarily evaluate the AccumulationBounds for
that expression.
The same expression can be evaluated to different values depending upon
the form it is used for substitution since each instance of an
AccumulationBounds is considered independent. For example:
>>> (x**2 + 2*x + 1).subs(x, AccumBounds(-1, 1))
AccumBounds(-1, 4)
>>> ((x + 1)**2).subs(x, AccumBounds(-1, 1))
AccumBounds(0, 4)
References
==========
.. [1] https://en.wikipedia.org/wiki/Interval_arithmetic
.. [2] https://fab.cba.mit.edu/classes/S62.12/docs/Hickey_interval.pdf
Notes
=====
Do not use ``AccumulationBounds`` for floating point interval arithmetic
calculations, use ``mpmath.iv`` instead.
"""
is_extended_real = True
is_number = False
def __new__(cls, min, max):
min = _sympify(min)
max = _sympify(max)
# Only allow real intervals (use symbols with 'is_extended_real=True').
if not min.is_extended_real or not max.is_extended_real:
raise ValueError("Only real AccumulationBounds are supported")
if max == min:
return max
# Make sure that the created AccumBounds object will be valid.
if max.is_number and min.is_number:
bad = max.is_comparable and min.is_comparable and max < min
else:
bad = (max - min).is_extended_negative
if bad:
raise ValueError(
"Lower limit should be smaller than upper limit")
return Basic.__new__(cls, min, max)
# setting the operation priority
_op_priority = 11.0
def _eval_is_real(self):
if self.min.is_real and self.max.is_real:
return True
@property
def min(self):
"""
Returns the minimum possible value attained by AccumulationBounds
object.
Examples
========
>>> from sympy import AccumBounds
>>> AccumBounds(1, 3).min
1
"""
return self.args[0]
@property
def max(self):
"""
Returns the maximum possible value attained by AccumulationBounds
object.
Examples
========
>>> from sympy import AccumBounds
>>> AccumBounds(1, 3).max
3
"""
return self.args[1]
@property
def delta(self):
"""
Returns the difference of maximum possible value attained by
AccumulationBounds object and minimum possible value attained
by AccumulationBounds object.
Examples
========
>>> from sympy import AccumBounds
>>> AccumBounds(1, 3).delta
2
"""
return self.max - self.min
@property
def mid(self):
"""
Returns the mean of maximum possible value attained by
AccumulationBounds object and minimum possible value
attained by AccumulationBounds object.
Examples
========
>>> from sympy import AccumBounds
>>> AccumBounds(1, 3).mid
2
"""
return (self.min + self.max) / 2
@_sympifyit('other', NotImplemented)
def _eval_power(self, other):
return self.__pow__(other)
@_sympifyit('other', NotImplemented)
def __add__(self, other):
if isinstance(other, Expr):
if isinstance(other, AccumBounds):
return AccumBounds(
Add(self.min, other.min),
Add(self.max, other.max))
if other is S.Infinity and self.min is S.NegativeInfinity or \
other is S.NegativeInfinity and self.max is S.Infinity:
return AccumBounds(-oo, oo)
elif other.is_extended_real:
if self.min is S.NegativeInfinity and self.max is S.Infinity:
return AccumBounds(-oo, oo)
elif self.min is S.NegativeInfinity:
return AccumBounds(-oo, self.max + other)
elif self.max is S.Infinity:
return AccumBounds(self.min + other, oo)
else:
return AccumBounds(Add(self.min, other), Add(self.max, other))
return Add(self, other, evaluate=False)
return NotImplemented
__radd__ = __add__
def __neg__(self):
return AccumBounds(-self.max, -self.min)
@_sympifyit('other', NotImplemented)
def __sub__(self, other):
if isinstance(other, Expr):
if isinstance(other, AccumBounds):
return AccumBounds(
Add(self.min, -other.max),
Add(self.max, -other.min))
if other is S.NegativeInfinity and self.min is S.NegativeInfinity or \
other is S.Infinity and self.max is S.Infinity:
return AccumBounds(-oo, oo)
elif other.is_extended_real:
if self.min is S.NegativeInfinity and self.max is S.Infinity:
return AccumBounds(-oo, oo)
elif self.min is S.NegativeInfinity:
return AccumBounds(-oo, self.max - other)
elif self.max is S.Infinity:
return AccumBounds(self.min - other, oo)
else:
return AccumBounds(
Add(self.min, -other),
Add(self.max, -other))
return Add(self, -other, evaluate=False)
return NotImplemented
@_sympifyit('other', NotImplemented)
def __rsub__(self, other):
return self.__neg__() + other
@_sympifyit('other', NotImplemented)
def __mul__(self, other):
if self.args == (-oo, oo):
return self
if isinstance(other, Expr):
if isinstance(other, AccumBounds):
if other.args == (-oo, oo):
return other
v = set()
for a in self.args:
vi = other*a
v.update(vi.args or (vi,))
return AccumBounds(Min(*v), Max(*v))
if other is S.Infinity:
if self.min.is_zero:
return AccumBounds(0, oo)
if self.max.is_zero:
return AccumBounds(-oo, 0)
if other is S.NegativeInfinity:
if self.min.is_zero:
return AccumBounds(-oo, 0)
if self.max.is_zero:
return AccumBounds(0, oo)
if other.is_extended_real:
if other.is_zero:
if self.max is S.Infinity:
return AccumBounds(0, oo)
if self.min is S.NegativeInfinity:
return AccumBounds(-oo, 0)
return S.Zero
if other.is_extended_positive:
return AccumBounds(
Mul(self.min, other),
Mul(self.max, other))
elif other.is_extended_negative:
return AccumBounds(
Mul(self.max, other),
Mul(self.min, other))
if isinstance(other, Order):
return other
return Mul(self, other, evaluate=False)
return NotImplemented
__rmul__ = __mul__
@_sympifyit('other', NotImplemented)
def __truediv__(self, other):
if isinstance(other, Expr):
if isinstance(other, AccumBounds):
if other.min.is_positive or other.max.is_negative:
return self * AccumBounds(1/other.max, 1/other.min)
if (self.min.is_extended_nonpositive and self.max.is_extended_nonnegative and
other.min.is_extended_nonpositive and other.max.is_extended_nonnegative):
if self.min.is_zero and other.min.is_zero:
return AccumBounds(0, oo)
if self.max.is_zero and other.min.is_zero:
return AccumBounds(-oo, 0)
return AccumBounds(-oo, oo)
if self.max.is_extended_negative:
if other.min.is_extended_negative:
if other.max.is_zero:
return AccumBounds(self.max / other.min, oo)
if other.max.is_extended_positive:
# if we were dealing with intervals we would return
# Union(Interval(-oo, self.max/other.max),
# Interval(self.max/other.min, oo))
return AccumBounds(-oo, oo)
if other.min.is_zero and other.max.is_extended_positive:
return AccumBounds(-oo, self.max / other.max)
if self.min.is_extended_positive:
if other.min.is_extended_negative:
if other.max.is_zero:
return AccumBounds(-oo, self.min / other.min)
if other.max.is_extended_positive:
# if we were dealing with intervals we would return
# Union(Interval(-oo, self.min/other.min),
# Interval(self.min/other.max, oo))
return AccumBounds(-oo, oo)
if other.min.is_zero and other.max.is_extended_positive:
return AccumBounds(self.min / other.max, oo)
elif other.is_extended_real:
if other in (S.Infinity, S.NegativeInfinity):
if self == AccumBounds(-oo, oo):
return AccumBounds(-oo, oo)
if self.max is S.Infinity:
return AccumBounds(Min(0, other), Max(0, other))
if self.min is S.NegativeInfinity:
return AccumBounds(Min(0, -other), Max(0, -other))
if other.is_extended_positive:
return AccumBounds(self.min / other, self.max / other)
elif other.is_extended_negative:
return AccumBounds(self.max / other, self.min / other)
if (1 / other) is S.ComplexInfinity:
return Mul(self, 1 / other, evaluate=False)
else:
return Mul(self, 1 / other)
return NotImplemented
@_sympifyit('other', NotImplemented)
def __rtruediv__(self, other):
if isinstance(other, Expr):
if other.is_extended_real:
if other.is_zero:
return S.Zero
if (self.min.is_extended_nonpositive and self.max.is_extended_nonnegative):
if self.min.is_zero:
if other.is_extended_positive:
return AccumBounds(Mul(other, 1 / self.max), oo)
if other.is_extended_negative:
return AccumBounds(-oo, Mul(other, 1 / self.max))
if self.max.is_zero:
if other.is_extended_positive:
return AccumBounds(-oo, Mul(other, 1 / self.min))
if other.is_extended_negative:
return AccumBounds(Mul(other, 1 / self.min), oo)
return AccumBounds(-oo, oo)
else:
return AccumBounds(Min(other / self.min, other / self.max),
Max(other / self.min, other / self.max))
return Mul(other, 1 / self, evaluate=False)
else:
return NotImplemented
@_sympifyit('other', NotImplemented)
def __pow__(self, other):
if isinstance(other, Expr):
if other is S.Infinity:
if self.min.is_extended_nonnegative:
if self.max < 1:
return S.Zero
if self.min > 1:
return S.Infinity
return AccumBounds(0, oo)
elif self.max.is_extended_negative:
if self.min > -1:
return S.Zero
if self.max < -1:
return zoo
return S.NaN
else:
if self.min > -1:
if self.max < 1:
return S.Zero
return AccumBounds(0, oo)
return AccumBounds(-oo, oo)
if other is S.NegativeInfinity:
return (1/self)**oo
# generically true
if (self.max - self.min).is_nonnegative:
# well defined
if self.min.is_nonnegative:
# no 0 to worry about
if other.is_nonnegative:
# no infinity to worry about
return self.func(self.min**other, self.max**other)
if other.is_zero:
return S.One # x**0 = 1
if other.is_Integer or other.is_integer:
if self.min.is_extended_positive:
return AccumBounds(
Min(self.min**other, self.max**other),
Max(self.min**other, self.max**other))
elif self.max.is_extended_negative:
return AccumBounds(
Min(self.max**other, self.min**other),
Max(self.max**other, self.min**other))
if other % 2 == 0:
if other.is_extended_negative:
if self.min.is_zero:
return AccumBounds(self.max**other, oo)
if self.max.is_zero:
return AccumBounds(self.min**other, oo)
return (1/self)**(-other)
return AccumBounds(
S.Zero, Max(self.min**other, self.max**other))
elif other % 2 == 1:
if other.is_extended_negative:
if self.min.is_zero:
return AccumBounds(self.max**other, oo)
if self.max.is_zero:
return AccumBounds(-oo, self.min**other)
return (1/self)**(-other)
return AccumBounds(self.min**other, self.max**other)
# non-integer exponent
# 0**neg or neg**frac yields complex
if (other.is_number or other.is_rational) and (
self.min.is_extended_nonnegative or (
other.is_extended_nonnegative and
self.min.is_extended_nonnegative)):
num, den = other.as_numer_denom()
if num is S.One:
return AccumBounds(*[i**(1/den) for i in self.args])
elif den is not S.One: # e.g. if other is not Float
return (self**num)**(1/den) # ok for non-negative base
if isinstance(other, AccumBounds):
if (self.min.is_extended_positive or
self.min.is_extended_nonnegative and
other.min.is_extended_nonnegative):
p = [self**i for i in other.args]
if not any(i.is_Pow for i in p):
a = [j for i in p for j in i.args or (i,)]
try:
return self.func(min(a), max(a))
except TypeError: # can't sort
pass
return Pow(self, other, evaluate=False)
return NotImplemented
@_sympifyit('other', NotImplemented)
def __rpow__(self, other):
if other.is_real and other.is_extended_nonnegative and (
self.max - self.min).is_extended_positive:
if other is S.One:
return S.One
if other.is_extended_positive:
a, b = [other**i for i in self.args]
if min(a, b) != a:
a, b = b, a
return self.func(a, b)
if other.is_zero:
if self.min.is_zero:
return self.func(0, 1)
if self.min.is_extended_positive:
return S.Zero
return Pow(other, self, evaluate=False)
def __abs__(self):
if self.max.is_extended_negative:
return self.__neg__()
elif self.min.is_extended_negative:
return AccumBounds(S.Zero, Max(abs(self.min), self.max))
else:
return self
def __contains__(self, other):
"""
Returns ``True`` if other is contained in self, where other
belongs to extended real numbers, ``False`` if not contained,
otherwise TypeError is raised.
Examples
========
>>> from sympy import AccumBounds, oo
>>> 1 in AccumBounds(-1, 3)
True
-oo and oo go together as limits (in AccumulationBounds).
>>> -oo in AccumBounds(1, oo)
True
>>> oo in AccumBounds(-oo, 0)
True
"""
other = _sympify(other)
if other in (S.Infinity, S.NegativeInfinity):
if self.min is S.NegativeInfinity or self.max is S.Infinity:
return True
return False
rv = And(self.min <= other, self.max >= other)
if rv not in (True, False):
raise TypeError("input failed to evaluate")
return rv
def intersection(self, other):
"""
Returns the intersection of 'self' and 'other'.
Here other can be an instance of :py:class:`~.FiniteSet` or AccumulationBounds.
Parameters
==========
other : AccumulationBounds
Another AccumulationBounds object with which the intersection
has to be computed.
Returns
=======
AccumulationBounds
Intersection of ``self`` and ``other``.
Examples
========
>>> from sympy import AccumBounds, FiniteSet
>>> AccumBounds(1, 3).intersection(AccumBounds(2, 4))
AccumBounds(2, 3)
>>> AccumBounds(1, 3).intersection(AccumBounds(4, 6))
EmptySet
>>> AccumBounds(1, 4).intersection(FiniteSet(1, 2, 5))
{1, 2}
"""
if not isinstance(other, (AccumBounds, FiniteSet)):
raise TypeError(
"Input must be AccumulationBounds or FiniteSet object")
if isinstance(other, FiniteSet):
fin_set = S.EmptySet
for i in other:
if i in self:
fin_set = fin_set + FiniteSet(i)
return fin_set
if self.max < other.min or self.min > other.max:
return S.EmptySet
if self.min <= other.min:
if self.max <= other.max:
return AccumBounds(other.min, self.max)
if self.max > other.max:
return other
if other.min <= self.min:
if other.max < self.max:
return AccumBounds(self.min, other.max)
if other.max > self.max:
return self
def union(self, other):
# TODO : Devise a better method for Union of AccumBounds
# this method is not actually correct and
# can be made better
if not isinstance(other, AccumBounds):
raise TypeError(
"Input must be AccumulationBounds or FiniteSet object")
if self.min <= other.min and self.max >= other.min:
return AccumBounds(self.min, Max(self.max, other.max))
if other.min <= self.min and other.max >= self.min:
return AccumBounds(other.min, Max(self.max, other.max))
@dispatch(AccumulationBounds, AccumulationBounds) # type: ignore # noqa:F811
def _eval_is_le(lhs, rhs): # noqa:F811
if is_le(lhs.max, rhs.min):
return True
if is_gt(lhs.min, rhs.max):
return False
@dispatch(AccumulationBounds, Basic) # type: ignore # noqa:F811
def _eval_is_le(lhs, rhs): # noqa: F811
"""
Returns ``True `` if range of values attained by ``lhs`` AccumulationBounds
object is greater than the range of values attained by ``rhs``,
where ``rhs`` may be any value of type AccumulationBounds object or
extended real number value, ``False`` if ``rhs`` satisfies
the same property, else an unevaluated :py:class:`~.Relational`.
Examples
========
>>> from sympy import AccumBounds, oo
>>> AccumBounds(1, 3) > AccumBounds(4, oo)
False
>>> AccumBounds(1, 4) > AccumBounds(3, 4)
AccumBounds(1, 4) > AccumBounds(3, 4)
>>> AccumBounds(1, oo) > -1
True
"""
if not rhs.is_extended_real:
raise TypeError(
"Invalid comparison of %s %s" %
(type(rhs), rhs))
elif rhs.is_comparable:
if is_le(lhs.max, rhs):
return True
if is_gt(lhs.min, rhs):
return False
@dispatch(AccumulationBounds, AccumulationBounds)
def _eval_is_ge(lhs, rhs): # noqa:F811
if is_ge(lhs.min, rhs.max):
return True
if is_lt(lhs.max, rhs.min):
return False
@dispatch(AccumulationBounds, Expr) # type:ignore
def _eval_is_ge(lhs, rhs): # noqa: F811
"""
Returns ``True`` if range of values attained by ``lhs`` AccumulationBounds
object is less that the range of values attained by ``rhs``, where
other may be any value of type AccumulationBounds object or extended
real number value, ``False`` if ``rhs`` satisfies the same
property, else an unevaluated :py:class:`~.Relational`.
Examples
========
>>> from sympy import AccumBounds, oo
>>> AccumBounds(1, 3) >= AccumBounds(4, oo)
False
>>> AccumBounds(1, 4) >= AccumBounds(3, 4)
AccumBounds(1, 4) >= AccumBounds(3, 4)
>>> AccumBounds(1, oo) >= 1
True
"""
if not rhs.is_extended_real:
raise TypeError(
"Invalid comparison of %s %s" %
(type(rhs), rhs))
elif rhs.is_comparable:
if is_ge(lhs.min, rhs):
return True
if is_lt(lhs.max, rhs):
return False
@dispatch(Expr, AccumulationBounds) # type:ignore
def _eval_is_ge(lhs, rhs): # noqa:F811
if not lhs.is_extended_real:
raise TypeError(
"Invalid comparison of %s %s" %
(type(lhs), lhs))
elif lhs.is_comparable:
if is_le(rhs.max, lhs):
return True
if is_gt(rhs.min, lhs):
return False
@dispatch(AccumulationBounds, AccumulationBounds) # type:ignore
def _eval_is_ge(lhs, rhs): # noqa:F811
if is_ge(lhs.min, rhs.max):
return True
if is_lt(lhs.max, rhs.min):
return False
# setting an alias for AccumulationBounds
AccumBounds = AccumulationBounds
PK ]ZZZ�/�l
l
sympy/calculus/euler.py"""
This module implements a method to find
Euler-Lagrange Equations for given Lagrangian.
"""
from itertools import combinations_with_replacement
from sympy.core.function import (Derivative, Function, diff)
from sympy.core.relational import Eq
from sympy.core.singleton import S
from sympy.core.symbol import Symbol
from sympy.core.sympify import sympify
from sympy.utilities.iterables import iterable
def euler_equations(L, funcs=(), vars=()):
r"""
Find the Euler-Lagrange equations [1]_ for a given Lagrangian.
Parameters
==========
L : Expr
The Lagrangian that should be a function of the functions listed
in the second argument and their derivatives.
For example, in the case of two functions $f(x,y)$, $g(x,y)$ and
two independent variables $x$, $y$ the Lagrangian has the form:
.. math:: L\left(f(x,y),g(x,y),\frac{\partial f(x,y)}{\partial x},
\frac{\partial f(x,y)}{\partial y},
\frac{\partial g(x,y)}{\partial x},
\frac{\partial g(x,y)}{\partial y},x,y\right)
In many cases it is not necessary to provide anything, except the
Lagrangian, it will be auto-detected (and an error raised if this
cannot be done).
funcs : Function or an iterable of Functions
The functions that the Lagrangian depends on. The Euler equations
are differential equations for each of these functions.
vars : Symbol or an iterable of Symbols
The Symbols that are the independent variables of the functions.
Returns
=======
eqns : list of Eq
The list of differential equations, one for each function.
Examples
========
>>> from sympy import euler_equations, Symbol, Function
>>> x = Function('x')
>>> t = Symbol('t')
>>> L = (x(t).diff(t))**2/2 - x(t)**2/2
>>> euler_equations(L, x(t), t)
[Eq(-x(t) - Derivative(x(t), (t, 2)), 0)]
>>> u = Function('u')
>>> x = Symbol('x')
>>> L = (u(t, x).diff(t))**2/2 - (u(t, x).diff(x))**2/2
>>> euler_equations(L, u(t, x), [t, x])
[Eq(-Derivative(u(t, x), (t, 2)) + Derivative(u(t, x), (x, 2)), 0)]
References
==========
.. [1] https://en.wikipedia.org/wiki/Euler%E2%80%93Lagrange_equation
"""
funcs = tuple(funcs) if iterable(funcs) else (funcs,)
if not funcs:
funcs = tuple(L.atoms(Function))
else:
for f in funcs:
if not isinstance(f, Function):
raise TypeError('Function expected, got: %s' % f)
vars = tuple(vars) if iterable(vars) else (vars,)
if not vars:
vars = funcs[0].args
else:
vars = tuple(sympify(var) for var in vars)
if not all(isinstance(v, Symbol) for v in vars):
raise TypeError('Variables are not symbols, got %s' % vars)
for f in funcs:
if not vars == f.args:
raise ValueError("Variables %s do not match args: %s" % (vars, f))
order = max([len(d.variables) for d in L.atoms(Derivative)
if d.expr in funcs] + [0])
eqns = []
for f in funcs:
eq = diff(L, f)
for i in range(1, order + 1):
for p in combinations_with_replacement(vars, i):
eq = eq + S.NegativeOne**i*diff(L, diff(f, *p), *p)
new_eq = Eq(eq, 0)
if isinstance(new_eq, Eq):
eqns.append(new_eq)
return eqns
PK ]ZZZCРםB �B sympy/calculus/finite_diff.py"""
Finite difference weights
=========================
This module implements an algorithm for efficient generation of finite
difference weights for ordinary differentials of functions for
derivatives from 0 (interpolation) up to arbitrary order.
The core algorithm is provided in the finite difference weight generating
function (``finite_diff_weights``), and two convenience functions are provided
for:
- estimating a derivative (or interpolate) directly from a series of points
is also provided (``apply_finite_diff``).
- differentiating by using finite difference approximations
(``differentiate_finite``).
"""
from sympy.core.function import Derivative
from sympy.core.singleton import S
from sympy.core.function import Subs
from sympy.core.traversal import preorder_traversal
from sympy.utilities.exceptions import sympy_deprecation_warning
from sympy.utilities.iterables import iterable
def finite_diff_weights(order, x_list, x0=S.One):
"""
Calculates the finite difference weights for an arbitrarily spaced
one-dimensional grid (``x_list``) for derivatives at ``x0`` of order
0, 1, ..., up to ``order`` using a recursive formula. Order of accuracy
is at least ``len(x_list) - order``, if ``x_list`` is defined correctly.
Parameters
==========
order: int
Up to what derivative order weights should be calculated.
0 corresponds to interpolation.
x_list: sequence
Sequence of (unique) values for the independent variable.
It is useful (but not necessary) to order ``x_list`` from
nearest to furthest from ``x0``; see examples below.
x0: Number or Symbol
Root or value of the independent variable for which the finite
difference weights should be generated. Default is ``S.One``.
Returns
=======
list
A list of sublists, each corresponding to coefficients for
increasing derivative order, and each containing lists of
coefficients for increasing subsets of x_list.
Examples
========
>>> from sympy import finite_diff_weights, S
>>> res = finite_diff_weights(1, [-S(1)/2, S(1)/2, S(3)/2, S(5)/2], 0)
>>> res
[[[1, 0, 0, 0],
[1/2, 1/2, 0, 0],
[3/8, 3/4, -1/8, 0],
[5/16, 15/16, -5/16, 1/16]],
[[0, 0, 0, 0],
[-1, 1, 0, 0],
[-1, 1, 0, 0],
[-23/24, 7/8, 1/8, -1/24]]]
>>> res[0][-1] # FD weights for 0th derivative, using full x_list
[5/16, 15/16, -5/16, 1/16]
>>> res[1][-1] # FD weights for 1st derivative
[-23/24, 7/8, 1/8, -1/24]
>>> res[1][-2] # FD weights for 1st derivative, using x_list[:-1]
[-1, 1, 0, 0]
>>> res[1][-1][0] # FD weight for 1st deriv. for x_list[0]
-23/24
>>> res[1][-1][1] # FD weight for 1st deriv. for x_list[1], etc.
7/8
Each sublist contains the most accurate formula at the end.
Note, that in the above example ``res[1][1]`` is the same as ``res[1][2]``.
Since res[1][2] has an order of accuracy of
``len(x_list[:3]) - order = 3 - 1 = 2``, the same is true for ``res[1][1]``!
>>> res = finite_diff_weights(1, [S(0), S(1), -S(1), S(2), -S(2)], 0)[1]
>>> res
[[0, 0, 0, 0, 0],
[-1, 1, 0, 0, 0],
[0, 1/2, -1/2, 0, 0],
[-1/2, 1, -1/3, -1/6, 0],
[0, 2/3, -2/3, -1/12, 1/12]]
>>> res[0] # no approximation possible, using x_list[0] only
[0, 0, 0, 0, 0]
>>> res[1] # classic forward step approximation
[-1, 1, 0, 0, 0]
>>> res[2] # classic centered approximation
[0, 1/2, -1/2, 0, 0]
>>> res[3:] # higher order approximations
[[-1/2, 1, -1/3, -1/6, 0], [0, 2/3, -2/3, -1/12, 1/12]]
Let us compare this to a differently defined ``x_list``. Pay attention to
``foo[i][k]`` corresponding to the gridpoint defined by ``x_list[k]``.
>>> foo = finite_diff_weights(1, [-S(2), -S(1), S(0), S(1), S(2)], 0)[1]
>>> foo
[[0, 0, 0, 0, 0],
[-1, 1, 0, 0, 0],
[1/2, -2, 3/2, 0, 0],
[1/6, -1, 1/2, 1/3, 0],
[1/12, -2/3, 0, 2/3, -1/12]]
>>> foo[1] # not the same and of lower accuracy as res[1]!
[-1, 1, 0, 0, 0]
>>> foo[2] # classic double backward step approximation
[1/2, -2, 3/2, 0, 0]
>>> foo[4] # the same as res[4]
[1/12, -2/3, 0, 2/3, -1/12]
Note that, unless you plan on using approximations based on subsets of
``x_list``, the order of gridpoints does not matter.
The capability to generate weights at arbitrary points can be
used e.g. to minimize Runge's phenomenon by using Chebyshev nodes:
>>> from sympy import cos, symbols, pi, simplify
>>> N, (h, x) = 4, symbols('h x')
>>> x_list = [x+h*cos(i*pi/(N)) for i in range(N,-1,-1)] # chebyshev nodes
>>> print(x_list)
[-h + x, -sqrt(2)*h/2 + x, x, sqrt(2)*h/2 + x, h + x]
>>> mycoeffs = finite_diff_weights(1, x_list, 0)[1][4]
>>> [simplify(c) for c in mycoeffs] #doctest: +NORMALIZE_WHITESPACE
[(h**3/2 + h**2*x - 3*h*x**2 - 4*x**3)/h**4,
(-sqrt(2)*h**3 - 4*h**2*x + 3*sqrt(2)*h*x**2 + 8*x**3)/h**4,
(6*h**2*x - 8*x**3)/h**4,
(sqrt(2)*h**3 - 4*h**2*x - 3*sqrt(2)*h*x**2 + 8*x**3)/h**4,
(-h**3/2 + h**2*x + 3*h*x**2 - 4*x**3)/h**4]
Notes
=====
If weights for a finite difference approximation of 3rd order
derivative is wanted, weights for 0th, 1st and 2nd order are
calculated "for free", so are formulae using subsets of ``x_list``.
This is something one can take advantage of to save computational cost.
Be aware that one should define ``x_list`` from nearest to furthest from
``x0``. If not, subsets of ``x_list`` will yield poorer approximations,
which might not grand an order of accuracy of ``len(x_list) - order``.
See also
========
sympy.calculus.finite_diff.apply_finite_diff
References
==========
.. [1] Generation of Finite Difference Formulas on Arbitrarily Spaced
Grids, Bengt Fornberg; Mathematics of computation; 51; 184;
(1988); 699-706; doi:10.1090/S0025-5718-1988-0935077-0
"""
# The notation below closely corresponds to the one used in the paper.
order = S(order)
if not order.is_number:
raise ValueError("Cannot handle symbolic order.")
if order < 0:
raise ValueError("Negative derivative order illegal.")
if int(order) != order:
raise ValueError("Non-integer order illegal")
M = order
N = len(x_list) - 1
delta = [[[0 for nu in range(N+1)] for n in range(N+1)] for
m in range(M+1)]
delta[0][0][0] = S.One
c1 = S.One
for n in range(1, N+1):
c2 = S.One
for nu in range(n):
c3 = x_list[n] - x_list[nu]
c2 = c2 * c3
if n <= M:
delta[n][n-1][nu] = 0
for m in range(min(n, M)+1):
delta[m][n][nu] = (x_list[n]-x0)*delta[m][n-1][nu] -\
m*delta[m-1][n-1][nu]
delta[m][n][nu] /= c3
for m in range(min(n, M)+1):
delta[m][n][n] = c1/c2*(m*delta[m-1][n-1][n-1] -
(x_list[n-1]-x0)*delta[m][n-1][n-1])
c1 = c2
return delta
def apply_finite_diff(order, x_list, y_list, x0=S.Zero):
"""
Calculates the finite difference approximation of
the derivative of requested order at ``x0`` from points
provided in ``x_list`` and ``y_list``.
Parameters
==========
order: int
order of derivative to approximate. 0 corresponds to interpolation.
x_list: sequence
Sequence of (unique) values for the independent variable.
y_list: sequence
The function value at corresponding values for the independent
variable in x_list.
x0: Number or Symbol
At what value of the independent variable the derivative should be
evaluated. Defaults to 0.
Returns
=======
sympy.core.add.Add or sympy.core.numbers.Number
The finite difference expression approximating the requested
derivative order at ``x0``.
Examples
========
>>> from sympy import apply_finite_diff
>>> cube = lambda arg: (1.0*arg)**3
>>> xlist = range(-3,3+1)
>>> apply_finite_diff(2, xlist, map(cube, xlist), 2) - 12 # doctest: +SKIP
-3.55271367880050e-15
we see that the example above only contain rounding errors.
apply_finite_diff can also be used on more abstract objects:
>>> from sympy import IndexedBase, Idx
>>> x, y = map(IndexedBase, 'xy')
>>> i = Idx('i')
>>> x_list, y_list = zip(*[(x[i+j], y[i+j]) for j in range(-1,2)])
>>> apply_finite_diff(1, x_list, y_list, x[i])
((x[i + 1] - x[i])/(-x[i - 1] + x[i]) - 1)*y[i]/(x[i + 1] - x[i]) -
(x[i + 1] - x[i])*y[i - 1]/((x[i + 1] - x[i - 1])*(-x[i - 1] + x[i])) +
(-x[i - 1] + x[i])*y[i + 1]/((x[i + 1] - x[i - 1])*(x[i + 1] - x[i]))
Notes
=====
Order = 0 corresponds to interpolation.
Only supply so many points you think makes sense
to around x0 when extracting the derivative (the function
need to be well behaved within that region). Also beware
of Runge's phenomenon.
See also
========
sympy.calculus.finite_diff.finite_diff_weights
References
==========
Fortran 90 implementation with Python interface for numerics: finitediff_
.. _finitediff: https://github.com/bjodah/finitediff
"""
# In the original paper the following holds for the notation:
# M = order
# N = len(x_list) - 1
N = len(x_list) - 1
if len(x_list) != len(y_list):
raise ValueError("x_list and y_list not equal in length.")
delta = finite_diff_weights(order, x_list, x0)
derivative = 0
for nu in range(len(x_list)):
derivative += delta[order][N][nu]*y_list[nu]
return derivative
def _as_finite_diff(derivative, points=1, x0=None, wrt=None):
"""
Returns an approximation of a derivative of a function in
the form of a finite difference formula. The expression is a
weighted sum of the function at a number of discrete values of
(one of) the independent variable(s).
Parameters
==========
derivative: a Derivative instance
points: sequence or coefficient, optional
If sequence: discrete values (length >= order+1) of the
independent variable used for generating the finite
difference weights.
If it is a coefficient, it will be used as the step-size
for generating an equidistant sequence of length order+1
centered around ``x0``. default: 1 (step-size 1)
x0: number or Symbol, optional
the value of the independent variable (``wrt``) at which the
derivative is to be approximated. Default: same as ``wrt``.
wrt: Symbol, optional
"with respect to" the variable for which the (partial)
derivative is to be approximated for. If not provided it
is required that the Derivative is ordinary. Default: ``None``.
Examples
========
>>> from sympy import symbols, Function, exp, sqrt, Symbol
>>> from sympy.calculus.finite_diff import _as_finite_diff
>>> x, h = symbols('x h')
>>> f = Function('f')
>>> _as_finite_diff(f(x).diff(x))
-f(x - 1/2) + f(x + 1/2)
The default step size and number of points are 1 and ``order + 1``
respectively. We can change the step size by passing a symbol
as a parameter:
>>> _as_finite_diff(f(x).diff(x), h)
-f(-h/2 + x)/h + f(h/2 + x)/h
We can also specify the discretized values to be used in a sequence:
>>> _as_finite_diff(f(x).diff(x), [x, x+h, x+2*h])
-3*f(x)/(2*h) + 2*f(h + x)/h - f(2*h + x)/(2*h)
The algorithm is not restricted to use equidistant spacing, nor
do we need to make the approximation around ``x0``, but we can get
an expression estimating the derivative at an offset:
>>> e, sq2 = exp(1), sqrt(2)
>>> xl = [x-h, x+h, x+e*h]
>>> _as_finite_diff(f(x).diff(x, 1), xl, x+h*sq2)
2*h*((h + sqrt(2)*h)/(2*h) - (-sqrt(2)*h + h)/(2*h))*f(E*h + x)/((-h + E*h)*(h + E*h)) +
(-(-sqrt(2)*h + h)/(2*h) - (-sqrt(2)*h + E*h)/(2*h))*f(-h + x)/(h + E*h) +
(-(h + sqrt(2)*h)/(2*h) + (-sqrt(2)*h + E*h)/(2*h))*f(h + x)/(-h + E*h)
Partial derivatives are also supported:
>>> y = Symbol('y')
>>> d2fdxdy=f(x,y).diff(x,y)
>>> _as_finite_diff(d2fdxdy, wrt=x)
-Derivative(f(x - 1/2, y), y) + Derivative(f(x + 1/2, y), y)
See also
========
sympy.calculus.finite_diff.apply_finite_diff
sympy.calculus.finite_diff.finite_diff_weights
"""
if derivative.is_Derivative:
pass
elif derivative.is_Atom:
return derivative
else:
return derivative.fromiter(
[_as_finite_diff(ar, points, x0, wrt) for ar
in derivative.args], **derivative.assumptions0)
if wrt is None:
old = None
for v in derivative.variables:
if old is v:
continue
derivative = _as_finite_diff(derivative, points, x0, v)
old = v
return derivative
order = derivative.variables.count(wrt)
if x0 is None:
x0 = wrt
if not iterable(points):
if getattr(points, 'is_Function', False) and wrt in points.args:
points = points.subs(wrt, x0)
# points is simply the step-size, let's make it a
# equidistant sequence centered around x0
if order % 2 == 0:
# even order => odd number of points, grid point included
points = [x0 + points*i for i
in range(-order//2, order//2 + 1)]
else:
# odd order => even number of points, half-way wrt grid point
points = [x0 + points*S(i)/2 for i
in range(-order, order + 1, 2)]
others = [wrt, 0]
for v in set(derivative.variables):
if v == wrt:
continue
others += [v, derivative.variables.count(v)]
if len(points) < order+1:
raise ValueError("Too few points for order %d" % order)
return apply_finite_diff(order, points, [
Derivative(derivative.expr.subs({wrt: x}), *others) for
x in points], x0)
def differentiate_finite(expr, *symbols,
points=1, x0=None, wrt=None, evaluate=False):
r""" Differentiate expr and replace Derivatives with finite differences.
Parameters
==========
expr : expression
\*symbols : differentiate with respect to symbols
points: sequence, coefficient or undefined function, optional
see ``Derivative.as_finite_difference``
x0: number or Symbol, optional
see ``Derivative.as_finite_difference``
wrt: Symbol, optional
see ``Derivative.as_finite_difference``
Examples
========
>>> from sympy import sin, Function, differentiate_finite
>>> from sympy.abc import x, y, h
>>> f, g = Function('f'), Function('g')
>>> differentiate_finite(f(x)*g(x), x, points=[x-h, x+h])
-f(-h + x)*g(-h + x)/(2*h) + f(h + x)*g(h + x)/(2*h)
``differentiate_finite`` works on any expression, including the expressions
with embedded derivatives:
>>> differentiate_finite(f(x) + sin(x), x, 2)
-2*f(x) + f(x - 1) + f(x + 1) - 2*sin(x) + sin(x - 1) + sin(x + 1)
>>> differentiate_finite(f(x, y), x, y)
f(x - 1/2, y - 1/2) - f(x - 1/2, y + 1/2) - f(x + 1/2, y - 1/2) + f(x + 1/2, y + 1/2)
>>> differentiate_finite(f(x)*g(x).diff(x), x)
(-g(x) + g(x + 1))*f(x + 1/2) - (g(x) - g(x - 1))*f(x - 1/2)
To make finite difference with non-constant discretization step use
undefined functions:
>>> dx = Function('dx')
>>> differentiate_finite(f(x)*g(x).diff(x), points=dx(x))
-(-g(x - dx(x)/2 - dx(x - dx(x)/2)/2)/dx(x - dx(x)/2) +
g(x - dx(x)/2 + dx(x - dx(x)/2)/2)/dx(x - dx(x)/2))*f(x - dx(x)/2)/dx(x) +
(-g(x + dx(x)/2 - dx(x + dx(x)/2)/2)/dx(x + dx(x)/2) +
g(x + dx(x)/2 + dx(x + dx(x)/2)/2)/dx(x + dx(x)/2))*f(x + dx(x)/2)/dx(x)
"""
if any(term.is_Derivative for term in list(preorder_traversal(expr))):
evaluate = False
Dexpr = expr.diff(*symbols, evaluate=evaluate)
if evaluate:
sympy_deprecation_warning("""
The evaluate flag to differentiate_finite() is deprecated.
evaluate=True expands the intermediate derivatives before computing
differences, but this usually not what you want, as it does not
satisfy the product rule.
""",
deprecated_since_version="1.5",
active_deprecations_target="deprecated-differentiate_finite-evaluate",
)
return Dexpr.replace(
lambda arg: arg.is_Derivative,
lambda arg: arg.as_finite_difference(points=points, x0=x0, wrt=wrt))
else:
DFexpr = Dexpr.as_finite_difference(points=points, x0=x0, wrt=wrt)
return DFexpr.replace(
lambda arg: isinstance(arg, Subs),
lambda arg: arg.expr.as_finite_difference(
points=points, x0=arg.point[0], wrt=arg.variables[0]))
PK ]ZZZ��@И/ �/ sympy/calculus/singularities.py"""
Singularities
=============
This module implements algorithms for finding singularities for a function
and identifying types of functions.
The differential calculus methods in this module include methods to identify
the following function types in the given ``Interval``:
- Increasing
- Strictly Increasing
- Decreasing
- Strictly Decreasing
- Monotonic
"""
from sympy.core.power import Pow
from sympy.core.singleton import S
from sympy.core.symbol import Symbol
from sympy.core.sympify import sympify
from sympy.functions.elementary.exponential import log
from sympy.functions.elementary.trigonometric import sec, csc, cot, tan, cos
from sympy.functions.elementary.hyperbolic import (
sech, csch, coth, tanh, cosh, asech, acsch, atanh, acoth)
from sympy.utilities.misc import filldedent
def singularities(expression, symbol, domain=None):
"""
Find singularities of a given function.
Parameters
==========
expression : Expr
The target function in which singularities need to be found.
symbol : Symbol
The symbol over the values of which the singularity in
expression in being searched for.
Returns
=======
Set
A set of values for ``symbol`` for which ``expression`` has a
singularity. An ``EmptySet`` is returned if ``expression`` has no
singularities for any given value of ``Symbol``.
Raises
======
NotImplementedError
Methods for determining the singularities of this function have
not been developed.
Notes
=====
This function does not find non-isolated singularities
nor does it find branch points of the expression.
Currently supported functions are:
- univariate continuous (real or complex) functions
References
==========
.. [1] https://en.wikipedia.org/wiki/Mathematical_singularity
Examples
========
>>> from sympy import singularities, Symbol, log
>>> x = Symbol('x', real=True)
>>> y = Symbol('y', real=False)
>>> singularities(x**2 + x + 1, x)
EmptySet
>>> singularities(1/(x + 1), x)
{-1}
>>> singularities(1/(y**2 + 1), y)
{-I, I}
>>> singularities(1/(y**3 + 1), y)
{-1, 1/2 - sqrt(3)*I/2, 1/2 + sqrt(3)*I/2}
>>> singularities(log(x), x)
{0}
"""
from sympy.solvers.solveset import solveset
if domain is None:
domain = S.Reals if symbol.is_real else S.Complexes
try:
sings = S.EmptySet
e = expression.rewrite([sec, csc, cot, tan], cos)
e = e.rewrite([sech, csch, coth, tanh], cosh)
for i in e.atoms(Pow):
if i.exp.is_infinite:
raise NotImplementedError
if i.exp.is_negative:
# XXX: exponent of varying sign not handled
sings += solveset(i.base, symbol, domain)
for i in expression.atoms(log, asech, acsch):
sings += solveset(i.args[0], symbol, domain)
for i in expression.atoms(atanh, acoth):
sings += solveset(i.args[0] - 1, symbol, domain)
sings += solveset(i.args[0] + 1, symbol, domain)
return sings
except NotImplementedError:
raise NotImplementedError(filldedent('''
Methods for determining the singularities
of this function have not been developed.'''))
###########################################################################
# DIFFERENTIAL CALCULUS METHODS #
###########################################################################
def monotonicity_helper(expression, predicate, interval=S.Reals, symbol=None):
"""
Helper function for functions checking function monotonicity.
Parameters
==========
expression : Expr
The target function which is being checked
predicate : function
The property being tested for. The function takes in an integer
and returns a boolean. The integer input is the derivative and
the boolean result should be true if the property is being held,
and false otherwise.
interval : Set, optional
The range of values in which we are testing, defaults to all reals.
symbol : Symbol, optional
The symbol present in expression which gets varied over the given range.
It returns a boolean indicating whether the interval in which
the function's derivative satisfies given predicate is a superset
of the given interval.
Returns
=======
Boolean
True if ``predicate`` is true for all the derivatives when ``symbol``
is varied in ``range``, False otherwise.
"""
from sympy.solvers.solveset import solveset
expression = sympify(expression)
free = expression.free_symbols
if symbol is None:
if len(free) > 1:
raise NotImplementedError(
'The function has not yet been implemented'
' for all multivariate expressions.'
)
variable = symbol or (free.pop() if free else Symbol('x'))
derivative = expression.diff(variable)
predicate_interval = solveset(predicate(derivative), variable, S.Reals)
return interval.is_subset(predicate_interval)
def is_increasing(expression, interval=S.Reals, symbol=None):
"""
Return whether the function is increasing in the given interval.
Parameters
==========
expression : Expr
The target function which is being checked.
interval : Set, optional
The range of values in which we are testing (defaults to set of
all real numbers).
symbol : Symbol, optional
The symbol present in expression which gets varied over the given range.
Returns
=======
Boolean
True if ``expression`` is increasing (either strictly increasing or
constant) in the given ``interval``, False otherwise.
Examples
========
>>> from sympy import is_increasing
>>> from sympy.abc import x, y
>>> from sympy import S, Interval, oo
>>> is_increasing(x**3 - 3*x**2 + 4*x, S.Reals)
True
>>> is_increasing(-x**2, Interval(-oo, 0))
True
>>> is_increasing(-x**2, Interval(0, oo))
False
>>> is_increasing(4*x**3 - 6*x**2 - 72*x + 30, Interval(-2, 3))
False
>>> is_increasing(x**2 + y, Interval(1, 2), x)
True
"""
return monotonicity_helper(expression, lambda x: x >= 0, interval, symbol)
def is_strictly_increasing(expression, interval=S.Reals, symbol=None):
"""
Return whether the function is strictly increasing in the given interval.
Parameters
==========
expression : Expr
The target function which is being checked.
interval : Set, optional
The range of values in which we are testing (defaults to set of
all real numbers).
symbol : Symbol, optional
The symbol present in expression which gets varied over the given range.
Returns
=======
Boolean
True if ``expression`` is strictly increasing in the given ``interval``,
False otherwise.
Examples
========
>>> from sympy import is_strictly_increasing
>>> from sympy.abc import x, y
>>> from sympy import Interval, oo
>>> is_strictly_increasing(4*x**3 - 6*x**2 - 72*x + 30, Interval.Ropen(-oo, -2))
True
>>> is_strictly_increasing(4*x**3 - 6*x**2 - 72*x + 30, Interval.Lopen(3, oo))
True
>>> is_strictly_increasing(4*x**3 - 6*x**2 - 72*x + 30, Interval.open(-2, 3))
False
>>> is_strictly_increasing(-x**2, Interval(0, oo))
False
>>> is_strictly_increasing(-x**2 + y, Interval(-oo, 0), x)
False
"""
return monotonicity_helper(expression, lambda x: x > 0, interval, symbol)
def is_decreasing(expression, interval=S.Reals, symbol=None):
"""
Return whether the function is decreasing in the given interval.
Parameters
==========
expression : Expr
The target function which is being checked.
interval : Set, optional
The range of values in which we are testing (defaults to set of
all real numbers).
symbol : Symbol, optional
The symbol present in expression which gets varied over the given range.
Returns
=======
Boolean
True if ``expression`` is decreasing (either strictly decreasing or
constant) in the given ``interval``, False otherwise.
Examples
========
>>> from sympy import is_decreasing
>>> from sympy.abc import x, y
>>> from sympy import S, Interval, oo
>>> is_decreasing(1/(x**2 - 3*x), Interval.open(S(3)/2, 3))
True
>>> is_decreasing(1/(x**2 - 3*x), Interval.open(1.5, 3))
True
>>> is_decreasing(1/(x**2 - 3*x), Interval.Lopen(3, oo))
True
>>> is_decreasing(1/(x**2 - 3*x), Interval.Ropen(-oo, S(3)/2))
False
>>> is_decreasing(1/(x**2 - 3*x), Interval.Ropen(-oo, 1.5))
False
>>> is_decreasing(-x**2, Interval(-oo, 0))
False
>>> is_decreasing(-x**2 + y, Interval(-oo, 0), x)
False
"""
return monotonicity_helper(expression, lambda x: x <= 0, interval, symbol)
def is_strictly_decreasing(expression, interval=S.Reals, symbol=None):
"""
Return whether the function is strictly decreasing in the given interval.
Parameters
==========
expression : Expr
The target function which is being checked.
interval : Set, optional
The range of values in which we are testing (defaults to set of
all real numbers).
symbol : Symbol, optional
The symbol present in expression which gets varied over the given range.
Returns
=======
Boolean
True if ``expression`` is strictly decreasing in the given ``interval``,
False otherwise.
Examples
========
>>> from sympy import is_strictly_decreasing
>>> from sympy.abc import x, y
>>> from sympy import S, Interval, oo
>>> is_strictly_decreasing(1/(x**2 - 3*x), Interval.Lopen(3, oo))
True
>>> is_strictly_decreasing(1/(x**2 - 3*x), Interval.Ropen(-oo, S(3)/2))
False
>>> is_strictly_decreasing(1/(x**2 - 3*x), Interval.Ropen(-oo, 1.5))
False
>>> is_strictly_decreasing(-x**2, Interval(-oo, 0))
False
>>> is_strictly_decreasing(-x**2 + y, Interval(-oo, 0), x)
False
"""
return monotonicity_helper(expression, lambda x: x < 0, interval, symbol)
def is_monotonic(expression, interval=S.Reals, symbol=None):
"""
Return whether the function is monotonic in the given interval.
Parameters
==========
expression : Expr
The target function which is being checked.
interval : Set, optional
The range of values in which we are testing (defaults to set of
all real numbers).
symbol : Symbol, optional
The symbol present in expression which gets varied over the given range.
Returns
=======
Boolean
True if ``expression`` is monotonic in the given ``interval``,
False otherwise.
Raises
======
NotImplementedError
Monotonicity check has not been implemented for the queried function.
Examples
========
>>> from sympy import is_monotonic
>>> from sympy.abc import x, y
>>> from sympy import S, Interval, oo
>>> is_monotonic(1/(x**2 - 3*x), Interval.open(S(3)/2, 3))
True
>>> is_monotonic(1/(x**2 - 3*x), Interval.open(1.5, 3))
True
>>> is_monotonic(1/(x**2 - 3*x), Interval.Lopen(3, oo))
True
>>> is_monotonic(x**3 - 3*x**2 + 4*x, S.Reals)
True
>>> is_monotonic(-x**2, S.Reals)
False
>>> is_monotonic(x**2 + y + 1, Interval(1, 2), x)
True
"""
from sympy.solvers.solveset import solveset
expression = sympify(expression)
free = expression.free_symbols
if symbol is None and len(free) > 1:
raise NotImplementedError(
'is_monotonic has not yet been implemented'
' for all multivariate expressions.'
)
variable = symbol or (free.pop() if free else Symbol('x'))
turning_points = solveset(expression.diff(variable), variable, interval)
return interval.intersection(turning_points) is S.EmptySet
PK ]ZZZ� ��xq xq sympy/calculus/util.pyfrom .accumulationbounds import AccumBounds, AccumulationBounds # noqa: F401
from .singularities import singularities
from sympy.core import Pow, S
from sympy.core.function import diff, expand_mul, Function
from sympy.core.kind import NumberKind
from sympy.core.mod import Mod
from sympy.core.numbers import equal_valued
from sympy.core.relational import Relational
from sympy.core.symbol import Symbol, Dummy
from sympy.core.sympify import _sympify
from sympy.functions.elementary.complexes import Abs, im, re
from sympy.functions.elementary.exponential import exp, log
from sympy.functions.elementary.integers import frac
from sympy.functions.elementary.piecewise import Piecewise
from sympy.functions.elementary.trigonometric import (
TrigonometricFunction, sin, cos, tan, cot, csc, sec,
asin, acos, acot, atan, asec, acsc)
from sympy.functions.elementary.hyperbolic import (sinh, cosh, tanh, coth,
sech, csch, asinh, acosh, atanh, acoth, asech, acsch)
from sympy.polys.polytools import degree, lcm_list
from sympy.sets.sets import (Interval, Intersection, FiniteSet, Union,
Complement)
from sympy.sets.fancysets import ImageSet
from sympy.sets.conditionset import ConditionSet
from sympy.utilities import filldedent
from sympy.utilities.iterables import iterable
from sympy.matrices.dense import hessian
def continuous_domain(f, symbol, domain):
"""
Returns the domain on which the function expression f is continuous.
This function is limited by the ability to determine the various
singularities and discontinuities of the given function.
The result is either given as a union of intervals or constructed using
other set operations.
Parameters
==========
f : :py:class:`~.Expr`
The concerned function.
symbol : :py:class:`~.Symbol`
The variable for which the intervals are to be determined.
domain : :py:class:`~.Interval`
The domain over which the continuity of the symbol has to be checked.
Examples
========
>>> from sympy import Interval, Symbol, S, tan, log, pi, sqrt
>>> from sympy.calculus.util import continuous_domain
>>> x = Symbol('x')
>>> continuous_domain(1/x, x, S.Reals)
Union(Interval.open(-oo, 0), Interval.open(0, oo))
>>> continuous_domain(tan(x), x, Interval(0, pi))
Union(Interval.Ropen(0, pi/2), Interval.Lopen(pi/2, pi))
>>> continuous_domain(sqrt(x - 2), x, Interval(-5, 5))
Interval(2, 5)
>>> continuous_domain(log(2*x - 1), x, S.Reals)
Interval.open(1/2, oo)
Returns
=======
:py:class:`~.Interval`
Union of all intervals where the function is continuous.
Raises
======
NotImplementedError
If the method to determine continuity of such a function
has not yet been developed.
"""
from sympy.solvers.inequalities import solve_univariate_inequality
if not domain.is_subset(S.Reals):
raise NotImplementedError(filldedent('''
Domain must be a subset of S.Reals.
'''))
implemented = [Pow, exp, log, Abs, frac,
sin, cos, tan, cot, sec, csc,
asin, acos, atan, acot, asec, acsc,
sinh, cosh, tanh, coth, sech, csch,
asinh, acosh, atanh, acoth, asech, acsch]
used = [fct.func for fct in f.atoms(Function) if fct.has(symbol)]
if any(func not in implemented for func in used):
raise NotImplementedError(filldedent('''
Unable to determine the domain of the given function.
'''))
x = Symbol('x')
constraints = {
log: (x > 0,),
asin: (x >= -1, x <= 1),
acos: (x >= -1, x <= 1),
acosh: (x >= 1,),
atanh: (x > -1, x < 1),
asech: (x > 0, x <= 1)
}
constraints_union = {
asec: (x <= -1, x >= 1),
acsc: (x <= -1, x >= 1),
acoth: (x < -1, x > 1)
}
cont_domain = domain
for atom in f.atoms(Pow):
den = atom.exp.as_numer_denom()[1]
if atom.exp.is_rational and den.is_odd:
pass # 0**negative handled by singularities()
else:
constraint = solve_univariate_inequality(atom.base >= 0,
symbol).as_set()
cont_domain = Intersection(constraint, cont_domain)
for atom in f.atoms(Function):
if atom.func in constraints:
for c in constraints[atom.func]:
constraint_relational = c.subs(x, atom.args[0])
constraint_set = solve_univariate_inequality(
constraint_relational, symbol).as_set()
cont_domain = Intersection(constraint_set, cont_domain)
elif atom.func in constraints_union:
constraint_set = S.EmptySet
for c in constraints_union[atom.func]:
constraint_relational = c.subs(x, atom.args[0])
constraint_set += solve_univariate_inequality(
constraint_relational, symbol).as_set()
cont_domain = Intersection(constraint_set, cont_domain)
# XXX: the discontinuities below could be factored out in
# a new "discontinuities()".
elif atom.func == acot:
from sympy.solvers.solveset import solveset_real
# Sympy's acot() has a step discontinuity at 0. Since it's
# neither an essential singularity nor a pole, singularities()
# will not report it. But it's still relevant for determining
# the continuity of the function f.
cont_domain -= solveset_real(atom.args[0], symbol)
# Note that the above may introduce spurious discontinuities, e.g.
# for abs(acot(x)) at 0.
elif atom.func == frac:
from sympy.solvers.solveset import solveset_real
r = function_range(atom.args[0], symbol, domain)
r = Intersection(r, S.Integers)
if r.is_finite_set:
discont = S.EmptySet
for n in r:
discont += solveset_real(atom.args[0]-n, symbol)
else:
discont = ConditionSet(
symbol, S.Integers.contains(atom.args[0]), cont_domain)
cont_domain -= discont
return cont_domain - singularities(f, symbol, domain)
def function_range(f, symbol, domain):
"""
Finds the range of a function in a given domain.
This method is limited by the ability to determine the singularities and
determine limits.
Parameters
==========
f : :py:class:`~.Expr`
The concerned function.
symbol : :py:class:`~.Symbol`
The variable for which the range of function is to be determined.
domain : :py:class:`~.Interval`
The domain under which the range of the function has to be found.
Examples
========
>>> from sympy import Interval, Symbol, S, exp, log, pi, sqrt, sin, tan
>>> from sympy.calculus.util import function_range
>>> x = Symbol('x')
>>> function_range(sin(x), x, Interval(0, 2*pi))
Interval(-1, 1)
>>> function_range(tan(x), x, Interval(-pi/2, pi/2))
Interval(-oo, oo)
>>> function_range(1/x, x, S.Reals)
Union(Interval.open(-oo, 0), Interval.open(0, oo))
>>> function_range(exp(x), x, S.Reals)
Interval.open(0, oo)
>>> function_range(log(x), x, S.Reals)
Interval(-oo, oo)
>>> function_range(sqrt(x), x, Interval(-5, 9))
Interval(0, 3)
Returns
=======
:py:class:`~.Interval`
Union of all ranges for all intervals under domain where function is
continuous.
Raises
======
NotImplementedError
If any of the intervals, in the given domain, for which function
is continuous are not finite or real,
OR if the critical points of the function on the domain cannot be found.
"""
if domain is S.EmptySet:
return S.EmptySet
period = periodicity(f, symbol)
if period == S.Zero:
# the expression is constant wrt symbol
return FiniteSet(f.expand())
from sympy.series.limits import limit
from sympy.solvers.solveset import solveset
if period is not None:
if isinstance(domain, Interval):
if (domain.inf - domain.sup).is_infinite:
domain = Interval(0, period)
elif isinstance(domain, Union):
for sub_dom in domain.args:
if isinstance(sub_dom, Interval) and \
((sub_dom.inf - sub_dom.sup).is_infinite):
domain = Interval(0, period)
intervals = continuous_domain(f, symbol, domain)
range_int = S.EmptySet
if isinstance(intervals,(Interval, FiniteSet)):
interval_iter = (intervals,)
elif isinstance(intervals, Union):
interval_iter = intervals.args
else:
raise NotImplementedError(filldedent('''
Unable to find range for the given domain.
'''))
for interval in interval_iter:
if isinstance(interval, FiniteSet):
for singleton in interval:
if singleton in domain:
range_int += FiniteSet(f.subs(symbol, singleton))
elif isinstance(interval, Interval):
vals = S.EmptySet
critical_points = S.EmptySet
critical_values = S.EmptySet
bounds = ((interval.left_open, interval.inf, '+'),
(interval.right_open, interval.sup, '-'))
for is_open, limit_point, direction in bounds:
if is_open:
critical_values += FiniteSet(limit(f, symbol, limit_point, direction))
vals += critical_values
else:
vals += FiniteSet(f.subs(symbol, limit_point))
solution = solveset(f.diff(symbol), symbol, interval)
if not iterable(solution):
raise NotImplementedError(
'Unable to find critical points for {}'.format(f))
if isinstance(solution, ImageSet):
raise NotImplementedError(
'Infinite number of critical points for {}'.format(f))
critical_points += solution
for critical_point in critical_points:
vals += FiniteSet(f.subs(symbol, critical_point))
left_open, right_open = False, False
if critical_values is not S.EmptySet:
if critical_values.inf == vals.inf:
left_open = True
if critical_values.sup == vals.sup:
right_open = True
range_int += Interval(vals.inf, vals.sup, left_open, right_open)
else:
raise NotImplementedError(filldedent('''
Unable to find range for the given domain.
'''))
return range_int
def not_empty_in(finset_intersection, *syms):
"""
Finds the domain of the functions in ``finset_intersection`` in which the
``finite_set`` is not-empty.
Parameters
==========
finset_intersection : Intersection of FiniteSet
The unevaluated intersection of FiniteSet containing
real-valued functions with Union of Sets
syms : Tuple of symbols
Symbol for which domain is to be found
Raises
======
NotImplementedError
The algorithms to find the non-emptiness of the given FiniteSet are
not yet implemented.
ValueError
The input is not valid.
RuntimeError
It is a bug, please report it to the github issue tracker
(https://github.com/sympy/sympy/issues).
Examples
========
>>> from sympy import FiniteSet, Interval, not_empty_in, oo
>>> from sympy.abc import x
>>> not_empty_in(FiniteSet(x/2).intersect(Interval(0, 1)), x)
Interval(0, 2)
>>> not_empty_in(FiniteSet(x, x**2).intersect(Interval(1, 2)), x)
Union(Interval(1, 2), Interval(-sqrt(2), -1))
>>> not_empty_in(FiniteSet(x**2/(x + 2)).intersect(Interval(1, oo)), x)
Union(Interval.Lopen(-2, -1), Interval(2, oo))
"""
# TODO: handle piecewise defined functions
# TODO: handle transcendental functions
# TODO: handle multivariate functions
if len(syms) == 0:
raise ValueError("One or more symbols must be given in syms.")
if finset_intersection is S.EmptySet:
return S.EmptySet
if isinstance(finset_intersection, Union):
elm_in_sets = finset_intersection.args[0]
return Union(not_empty_in(finset_intersection.args[1], *syms),
elm_in_sets)
if isinstance(finset_intersection, FiniteSet):
finite_set = finset_intersection
_sets = S.Reals
else:
finite_set = finset_intersection.args[1]
_sets = finset_intersection.args[0]
if not isinstance(finite_set, FiniteSet):
raise ValueError('A FiniteSet must be given, not %s: %s' %
(type(finite_set), finite_set))
if len(syms) == 1:
symb = syms[0]
else:
raise NotImplementedError('more than one variables %s not handled' %
(syms,))
def elm_domain(expr, intrvl):
""" Finds the domain of an expression in any given interval """
from sympy.solvers.solveset import solveset
_start = intrvl.start
_end = intrvl.end
_singularities = solveset(expr.as_numer_denom()[1], symb,
domain=S.Reals)
if intrvl.right_open:
if _end is S.Infinity:
_domain1 = S.Reals
else:
_domain1 = solveset(expr < _end, symb, domain=S.Reals)
else:
_domain1 = solveset(expr <= _end, symb, domain=S.Reals)
if intrvl.left_open:
if _start is S.NegativeInfinity:
_domain2 = S.Reals
else:
_domain2 = solveset(expr > _start, symb, domain=S.Reals)
else:
_domain2 = solveset(expr >= _start, symb, domain=S.Reals)
# domain in the interval
expr_with_sing = Intersection(_domain1, _domain2)
expr_domain = Complement(expr_with_sing, _singularities)
return expr_domain
if isinstance(_sets, Interval):
return Union(*[elm_domain(element, _sets) for element in finite_set])
if isinstance(_sets, Union):
_domain = S.EmptySet
for intrvl in _sets.args:
_domain_element = Union(*[elm_domain(element, intrvl)
for element in finite_set])
_domain = Union(_domain, _domain_element)
return _domain
def periodicity(f, symbol, check=False):
"""
Tests the given function for periodicity in the given symbol.
Parameters
==========
f : :py:class:`~.Expr`
The concerned function.
symbol : :py:class:`~.Symbol`
The variable for which the period is to be determined.
check : bool, optional
The flag to verify whether the value being returned is a period or not.
Returns
=======
period
The period of the function is returned.
``None`` is returned when the function is aperiodic or has a complex period.
The value of $0$ is returned as the period of a constant function.
Raises
======
NotImplementedError
The value of the period computed cannot be verified.
Notes
=====
Currently, we do not support functions with a complex period.
The period of functions having complex periodic values such
as ``exp``, ``sinh`` is evaluated to ``None``.
The value returned might not be the "fundamental" period of the given
function i.e. it may not be the smallest periodic value of the function.
The verification of the period through the ``check`` flag is not reliable
due to internal simplification of the given expression. Hence, it is set
to ``False`` by default.
Examples
========
>>> from sympy import periodicity, Symbol, sin, cos, tan, exp
>>> x = Symbol('x')
>>> f = sin(x) + sin(2*x) + sin(3*x)
>>> periodicity(f, x)
2*pi
>>> periodicity(sin(x)*cos(x), x)
pi
>>> periodicity(exp(tan(2*x) - 1), x)
pi/2
>>> periodicity(sin(4*x)**cos(2*x), x)
pi
>>> periodicity(exp(x), x)
"""
if symbol.kind is not NumberKind:
raise NotImplementedError("Cannot use symbol of kind %s" % symbol.kind)
temp = Dummy('x', real=True)
f = f.subs(symbol, temp)
symbol = temp
def _check(orig_f, period):
'''Return the checked period or raise an error.'''
new_f = orig_f.subs(symbol, symbol + period)
if new_f.equals(orig_f):
return period
else:
raise NotImplementedError(filldedent('''
The period of the given function cannot be verified.
When `%s` was replaced with `%s + %s` in `%s`, the result
was `%s` which was not recognized as being the same as
the original function.
So either the period was wrong or the two forms were
not recognized as being equal.
Set check=False to obtain the value.''' %
(symbol, symbol, period, orig_f, new_f)))
orig_f = f
period = None
if isinstance(f, Relational):
f = f.lhs - f.rhs
f = f.simplify()
if symbol not in f.free_symbols:
return S.Zero
if isinstance(f, TrigonometricFunction):
try:
period = f.period(symbol)
except NotImplementedError:
pass
if isinstance(f, Abs):
arg = f.args[0]
if isinstance(arg, (sec, csc, cos)):
# all but tan and cot might have a
# a period that is half as large
# so recast as sin
arg = sin(arg.args[0])
period = periodicity(arg, symbol)
if period is not None and isinstance(arg, sin):
# the argument of Abs was a trigonometric other than
# cot or tan; test to see if the half-period
# is valid. Abs(arg) has behaviour equivalent to
# orig_f, so use that for test:
orig_f = Abs(arg)
try:
return _check(orig_f, period/2)
except NotImplementedError as err:
if check:
raise NotImplementedError(err)
# else let new orig_f and period be
# checked below
if isinstance(f, exp) or (f.is_Pow and f.base == S.Exp1):
f = Pow(S.Exp1, expand_mul(f.exp))
if im(f) != 0:
period_real = periodicity(re(f), symbol)
period_imag = periodicity(im(f), symbol)
if period_real is not None and period_imag is not None:
period = lcim([period_real, period_imag])
if f.is_Pow and f.base != S.Exp1:
base, expo = f.args
base_has_sym = base.has(symbol)
expo_has_sym = expo.has(symbol)
if base_has_sym and not expo_has_sym:
period = periodicity(base, symbol)
elif expo_has_sym and not base_has_sym:
period = periodicity(expo, symbol)
else:
period = _periodicity(f.args, symbol)
elif f.is_Mul:
coeff, g = f.as_independent(symbol, as_Add=False)
if isinstance(g, TrigonometricFunction) or not equal_valued(coeff, 1):
period = periodicity(g, symbol)
else:
period = _periodicity(g.args, symbol)
elif f.is_Add:
k, g = f.as_independent(symbol)
if k is not S.Zero:
return periodicity(g, symbol)
period = _periodicity(g.args, symbol)
elif isinstance(f, Mod):
a, n = f.args
if a == symbol:
period = n
elif isinstance(a, TrigonometricFunction):
period = periodicity(a, symbol)
#check if 'f' is linear in 'symbol'
elif (a.is_polynomial(symbol) and degree(a, symbol) == 1 and
symbol not in n.free_symbols):
period = Abs(n / a.diff(symbol))
elif isinstance(f, Piecewise):
pass # not handling Piecewise yet as the return type is not favorable
elif period is None:
from sympy.solvers.decompogen import compogen, decompogen
g_s = decompogen(f, symbol)
num_of_gs = len(g_s)
if num_of_gs > 1:
for index, g in enumerate(reversed(g_s)):
start_index = num_of_gs - 1 - index
g = compogen(g_s[start_index:], symbol)
if g not in (orig_f, f): # Fix for issue 12620
period = periodicity(g, symbol)
if period is not None:
break
if period is not None:
if check:
return _check(orig_f, period)
return period
return None
def _periodicity(args, symbol):
"""
Helper for `periodicity` to find the period of a list of simpler
functions.
It uses the `lcim` method to find the least common period of
all the functions.
Parameters
==========
args : Tuple of :py:class:`~.Symbol`
All the symbols present in a function.
symbol : :py:class:`~.Symbol`
The symbol over which the function is to be evaluated.
Returns
=======
period
The least common period of the function for all the symbols
of the function.
``None`` if for at least one of the symbols the function is aperiodic.
"""
periods = []
for f in args:
period = periodicity(f, symbol)
if period is None:
return None
if period is not S.Zero:
periods.append(period)
if len(periods) > 1:
return lcim(periods)
if periods:
return periods[0]
def lcim(numbers):
"""Returns the least common integral multiple of a list of numbers.
The numbers can be rational or irrational or a mixture of both.
`None` is returned for incommensurable numbers.
Parameters
==========
numbers : list
Numbers (rational and/or irrational) for which lcim is to be found.
Returns
=======
number
lcim if it exists, otherwise ``None`` for incommensurable numbers.
Examples
========
>>> from sympy.calculus.util import lcim
>>> from sympy import S, pi
>>> lcim([S(1)/2, S(3)/4, S(5)/6])
15/2
>>> lcim([2*pi, 3*pi, pi, pi/2])
6*pi
>>> lcim([S(1), 2*pi])
"""
result = None
if all(num.is_irrational for num in numbers):
factorized_nums = [num.factor() for num in numbers]
factors_num = [num.as_coeff_Mul() for num in factorized_nums]
term = factors_num[0][1]
if all(factor == term for coeff, factor in factors_num):
common_term = term
coeffs = [coeff for coeff, factor in factors_num]
result = lcm_list(coeffs) * common_term
elif all(num.is_rational for num in numbers):
result = lcm_list(numbers)
else:
pass
return result
def is_convex(f, *syms, domain=S.Reals):
r"""Determines the convexity of the function passed in the argument.
Parameters
==========
f : :py:class:`~.Expr`
The concerned function.
syms : Tuple of :py:class:`~.Symbol`
The variables with respect to which the convexity is to be determined.
domain : :py:class:`~.Interval`, optional
The domain over which the convexity of the function has to be checked.
If unspecified, S.Reals will be the default domain.
Returns
=======
bool
The method returns ``True`` if the function is convex otherwise it
returns ``False``.
Raises
======
NotImplementedError
The check for the convexity of multivariate functions is not implemented yet.
Notes
=====
To determine concavity of a function pass `-f` as the concerned function.
To determine logarithmic convexity of a function pass `\log(f)` as
concerned function.
To determine logarithmic concavity of a function pass `-\log(f)` as
concerned function.
Currently, convexity check of multivariate functions is not handled.
Examples
========
>>> from sympy import is_convex, symbols, exp, oo, Interval
>>> x = symbols('x')
>>> is_convex(exp(x), x)
True
>>> is_convex(x**3, x, domain = Interval(-1, oo))
False
>>> is_convex(1/x**2, x, domain=Interval.open(0, oo))
True
References
==========
.. [1] https://en.wikipedia.org/wiki/Convex_function
.. [2] http://www.ifp.illinois.edu/~angelia/L3_convfunc.pdf
.. [3] https://en.wikipedia.org/wiki/Logarithmically_convex_function
.. [4] https://en.wikipedia.org/wiki/Logarithmically_concave_function
.. [5] https://en.wikipedia.org/wiki/Concave_function
"""
if len(syms) > 1 :
return hessian(f, syms).is_positive_semidefinite
from sympy.solvers.inequalities import solve_univariate_inequality
f = _sympify(f)
var = syms[0]
if any(s in domain for s in singularities(f, var)):
return False
condition = f.diff(var, 2) < 0
if solve_univariate_inequality(condition, var, False, domain):
return False
return True
def stationary_points(f, symbol, domain=S.Reals):
"""
Returns the stationary points of a function (where derivative of the
function is 0) in the given domain.
Parameters
==========
f : :py:class:`~.Expr`
The concerned function.
symbol : :py:class:`~.Symbol`
The variable for which the stationary points are to be determined.
domain : :py:class:`~.Interval`
The domain over which the stationary points have to be checked.
If unspecified, ``S.Reals`` will be the default domain.
Returns
=======
Set
A set of stationary points for the function. If there are no
stationary point, an :py:class:`~.EmptySet` is returned.
Examples
========
>>> from sympy import Interval, Symbol, S, sin, pi, pprint, stationary_points
>>> x = Symbol('x')
>>> stationary_points(1/x, x, S.Reals)
EmptySet
>>> pprint(stationary_points(sin(x), x), use_unicode=False)
pi 3*pi
{2*n*pi + -- | n in Integers} U {2*n*pi + ---- | n in Integers}
2 2
>>> stationary_points(sin(x),x, Interval(0, 4*pi))
{pi/2, 3*pi/2, 5*pi/2, 7*pi/2}
"""
from sympy.solvers.solveset import solveset
if domain is S.EmptySet:
return S.EmptySet
domain = continuous_domain(f, symbol, domain)
set = solveset(diff(f, symbol), symbol, domain)
return set
def maximum(f, symbol, domain=S.Reals):
"""
Returns the maximum value of a function in the given domain.
Parameters
==========
f : :py:class:`~.Expr`
The concerned function.
symbol : :py:class:`~.Symbol`
The variable for maximum value needs to be determined.
domain : :py:class:`~.Interval`
The domain over which the maximum have to be checked.
If unspecified, then the global maximum is returned.
Returns
=======
number
Maximum value of the function in given domain.
Examples
========
>>> from sympy import Interval, Symbol, S, sin, cos, pi, maximum
>>> x = Symbol('x')
>>> f = -x**2 + 2*x + 5
>>> maximum(f, x, S.Reals)
6
>>> maximum(sin(x), x, Interval(-pi, pi/4))
sqrt(2)/2
>>> maximum(sin(x)*cos(x), x)
1/2
"""
if isinstance(symbol, Symbol):
if domain is S.EmptySet:
raise ValueError("Maximum value not defined for empty domain.")
return function_range(f, symbol, domain).sup
else:
raise ValueError("%s is not a valid symbol." % symbol)
def minimum(f, symbol, domain=S.Reals):
"""
Returns the minimum value of a function in the given domain.
Parameters
==========
f : :py:class:`~.Expr`
The concerned function.
symbol : :py:class:`~.Symbol`
The variable for minimum value needs to be determined.
domain : :py:class:`~.Interval`
The domain over which the minimum have to be checked.
If unspecified, then the global minimum is returned.
Returns
=======
number
Minimum value of the function in the given domain.
Examples
========
>>> from sympy import Interval, Symbol, S, sin, cos, minimum
>>> x = Symbol('x')
>>> f = x**2 + 2*x + 5
>>> minimum(f, x, S.Reals)
4
>>> minimum(sin(x), x, Interval(2, 3))
sin(3)
>>> minimum(sin(x)*cos(x), x)
-1/2
"""
if isinstance(symbol, Symbol):
if domain is S.EmptySet:
raise ValueError("Minimum value not defined for empty domain.")
return function_range(f, symbol, domain).inf
else:
raise ValueError("%s is not a valid symbol." % symbol)
PK ]ZZZ�k�� � sympy/categories/__init__.py"""
Category Theory module.
Provides some of the fundamental category-theory-related classes,
including categories, morphisms, diagrams. Functors are not
implemented yet.
The general reference work this module tries to follow is
[JoyOfCats] J. Adamek, H. Herrlich. G. E. Strecker: Abstract and
Concrete Categories. The Joy of Cats.
The latest version of this book should be available for free download
from
katmat.math.uni-bremen.de/acc/acc.pdf
"""
from .baseclasses import (Object, Morphism, IdentityMorphism,
NamedMorphism, CompositeMorphism, Category,
Diagram)
from .diagram_drawing import (DiagramGrid, XypicDiagramDrawer,
xypic_draw_diagram, preview_diagram)
__all__ = [
'Object', 'Morphism', 'IdentityMorphism', 'NamedMorphism',
'CompositeMorphism', 'Category', 'Diagram',
'DiagramGrid', 'XypicDiagramDrawer', 'xypic_draw_diagram',
'preview_diagram',
]
PK ]ZZZ�ݭ�z �z sympy/categories/baseclasses.pyfrom sympy.core import S, Basic, Dict, Symbol, Tuple, sympify
from sympy.core.symbol import Str
from sympy.sets import Set, FiniteSet, EmptySet
from sympy.utilities.iterables import iterable
class Class(Set):
r"""
The base class for any kind of class in the set-theoretic sense.
Explanation
===========
In axiomatic set theories, everything is a class. A class which
can be a member of another class is a set. A class which is not a
member of another class is a proper class. The class `\{1, 2\}`
is a set; the class of all sets is a proper class.
This class is essentially a synonym for :class:`sympy.core.Set`.
The goal of this class is to assure easier migration to the
eventual proper implementation of set theory.
"""
is_proper = False
class Object(Symbol):
"""
The base class for any kind of object in an abstract category.
Explanation
===========
While technically any instance of :class:`~.Basic` will do, this
class is the recommended way to create abstract objects in
abstract categories.
"""
class Morphism(Basic):
"""
The base class for any morphism in an abstract category.
Explanation
===========
In abstract categories, a morphism is an arrow between two
category objects. The object where the arrow starts is called the
domain, while the object where the arrow ends is called the
codomain.
Two morphisms between the same pair of objects are considered to
be the same morphisms. To distinguish between morphisms between
the same objects use :class:`NamedMorphism`.
It is prohibited to instantiate this class. Use one of the
derived classes instead.
See Also
========
IdentityMorphism, NamedMorphism, CompositeMorphism
"""
def __new__(cls, domain, codomain):
raise(NotImplementedError(
"Cannot instantiate Morphism. Use derived classes instead."))
@property
def domain(self):
"""
Returns the domain of the morphism.
Examples
========
>>> from sympy.categories import Object, NamedMorphism
>>> A = Object("A")
>>> B = Object("B")
>>> f = NamedMorphism(A, B, "f")
>>> f.domain
Object("A")
"""
return self.args[0]
@property
def codomain(self):
"""
Returns the codomain of the morphism.
Examples
========
>>> from sympy.categories import Object, NamedMorphism
>>> A = Object("A")
>>> B = Object("B")
>>> f = NamedMorphism(A, B, "f")
>>> f.codomain
Object("B")
"""
return self.args[1]
def compose(self, other):
r"""
Composes self with the supplied morphism.
The order of elements in the composition is the usual order,
i.e., to construct `g\circ f` use ``g.compose(f)``.
Examples
========
>>> from sympy.categories import Object, NamedMorphism
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> g * f
CompositeMorphism((NamedMorphism(Object("A"), Object("B"), "f"),
NamedMorphism(Object("B"), Object("C"), "g")))
>>> (g * f).domain
Object("A")
>>> (g * f).codomain
Object("C")
"""
return CompositeMorphism(other, self)
def __mul__(self, other):
r"""
Composes self with the supplied morphism.
The semantics of this operation is given by the following
equation: ``g * f == g.compose(f)`` for composable morphisms
``g`` and ``f``.
See Also
========
compose
"""
return self.compose(other)
class IdentityMorphism(Morphism):
"""
Represents an identity morphism.
Explanation
===========
An identity morphism is a morphism with equal domain and codomain,
which acts as an identity with respect to composition.
Examples
========
>>> from sympy.categories import Object, NamedMorphism, IdentityMorphism
>>> A = Object("A")
>>> B = Object("B")
>>> f = NamedMorphism(A, B, "f")
>>> id_A = IdentityMorphism(A)
>>> id_B = IdentityMorphism(B)
>>> f * id_A == f
True
>>> id_B * f == f
True
See Also
========
Morphism
"""
def __new__(cls, domain):
return Basic.__new__(cls, domain)
@property
def codomain(self):
return self.domain
class NamedMorphism(Morphism):
"""
Represents a morphism which has a name.
Explanation
===========
Names are used to distinguish between morphisms which have the
same domain and codomain: two named morphisms are equal if they
have the same domains, codomains, and names.
Examples
========
>>> from sympy.categories import Object, NamedMorphism
>>> A = Object("A")
>>> B = Object("B")
>>> f = NamedMorphism(A, B, "f")
>>> f
NamedMorphism(Object("A"), Object("B"), "f")
>>> f.name
'f'
See Also
========
Morphism
"""
def __new__(cls, domain, codomain, name):
if not name:
raise ValueError("Empty morphism names not allowed.")
if not isinstance(name, Str):
name = Str(name)
return Basic.__new__(cls, domain, codomain, name)
@property
def name(self):
"""
Returns the name of the morphism.
Examples
========
>>> from sympy.categories import Object, NamedMorphism
>>> A = Object("A")
>>> B = Object("B")
>>> f = NamedMorphism(A, B, "f")
>>> f.name
'f'
"""
return self.args[2].name
class CompositeMorphism(Morphism):
r"""
Represents a morphism which is a composition of other morphisms.
Explanation
===========
Two composite morphisms are equal if the morphisms they were
obtained from (components) are the same and were listed in the
same order.
The arguments to the constructor for this class should be listed
in diagram order: to obtain the composition `g\circ f` from the
instances of :class:`Morphism` ``g`` and ``f`` use
``CompositeMorphism(f, g)``.
Examples
========
>>> from sympy.categories import Object, NamedMorphism, CompositeMorphism
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> g * f
CompositeMorphism((NamedMorphism(Object("A"), Object("B"), "f"),
NamedMorphism(Object("B"), Object("C"), "g")))
>>> CompositeMorphism(f, g) == g * f
True
"""
@staticmethod
def _add_morphism(t, morphism):
"""
Intelligently adds ``morphism`` to tuple ``t``.
Explanation
===========
If ``morphism`` is a composite morphism, its components are
added to the tuple. If ``morphism`` is an identity, nothing
is added to the tuple.
No composability checks are performed.
"""
if isinstance(morphism, CompositeMorphism):
# ``morphism`` is a composite morphism; we have to
# denest its components.
return t + morphism.components
elif isinstance(morphism, IdentityMorphism):
# ``morphism`` is an identity. Nothing happens.
return t
else:
return t + Tuple(morphism)
def __new__(cls, *components):
if components and not isinstance(components[0], Morphism):
# Maybe the user has explicitly supplied a list of
# morphisms.
return CompositeMorphism.__new__(cls, *components[0])
normalised_components = Tuple()
for current, following in zip(components, components[1:]):
if not isinstance(current, Morphism) or \
not isinstance(following, Morphism):
raise TypeError("All components must be morphisms.")
if current.codomain != following.domain:
raise ValueError("Uncomposable morphisms.")
normalised_components = CompositeMorphism._add_morphism(
normalised_components, current)
# We haven't added the last morphism to the list of normalised
# components. Add it now.
normalised_components = CompositeMorphism._add_morphism(
normalised_components, components[-1])
if not normalised_components:
# If ``normalised_components`` is empty, only identities
# were supplied. Since they all were composable, they are
# all the same identities.
return components[0]
elif len(normalised_components) == 1:
# No sense to construct a whole CompositeMorphism.
return normalised_components[0]
return Basic.__new__(cls, normalised_components)
@property
def components(self):
"""
Returns the components of this composite morphism.
Examples
========
>>> from sympy.categories import Object, NamedMorphism
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> (g * f).components
(NamedMorphism(Object("A"), Object("B"), "f"),
NamedMorphism(Object("B"), Object("C"), "g"))
"""
return self.args[0]
@property
def domain(self):
"""
Returns the domain of this composite morphism.
The domain of the composite morphism is the domain of its
first component.
Examples
========
>>> from sympy.categories import Object, NamedMorphism
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> (g * f).domain
Object("A")
"""
return self.components[0].domain
@property
def codomain(self):
"""
Returns the codomain of this composite morphism.
The codomain of the composite morphism is the codomain of its
last component.
Examples
========
>>> from sympy.categories import Object, NamedMorphism
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> (g * f).codomain
Object("C")
"""
return self.components[-1].codomain
def flatten(self, new_name):
"""
Forgets the composite structure of this morphism.
Explanation
===========
If ``new_name`` is not empty, returns a :class:`NamedMorphism`
with the supplied name, otherwise returns a :class:`Morphism`.
In both cases the domain of the new morphism is the domain of
this composite morphism and the codomain of the new morphism
is the codomain of this composite morphism.
Examples
========
>>> from sympy.categories import Object, NamedMorphism
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> (g * f).flatten("h")
NamedMorphism(Object("A"), Object("C"), "h")
"""
return NamedMorphism(self.domain, self.codomain, new_name)
class Category(Basic):
r"""
An (abstract) category.
Explanation
===========
A category [JoyOfCats] is a quadruple `\mbox{K} = (O, \hom, id,
\circ)` consisting of
* a (set-theoretical) class `O`, whose members are called
`K`-objects,
* for each pair `(A, B)` of `K`-objects, a set `\hom(A, B)` whose
members are called `K`-morphisms from `A` to `B`,
* for a each `K`-object `A`, a morphism `id:A\rightarrow A`,
called the `K`-identity of `A`,
* a composition law `\circ` associating with every `K`-morphisms
`f:A\rightarrow B` and `g:B\rightarrow C` a `K`-morphism `g\circ
f:A\rightarrow C`, called the composite of `f` and `g`.
Composition is associative, `K`-identities are identities with
respect to composition, and the sets `\hom(A, B)` are pairwise
disjoint.
This class knows nothing about its objects and morphisms.
Concrete cases of (abstract) categories should be implemented as
classes derived from this one.
Certain instances of :class:`Diagram` can be asserted to be
commutative in a :class:`Category` by supplying the argument
``commutative_diagrams`` in the constructor.
Examples
========
>>> from sympy.categories import Object, NamedMorphism, Diagram, Category
>>> from sympy import FiniteSet
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> d = Diagram([f, g])
>>> K = Category("K", commutative_diagrams=[d])
>>> K.commutative_diagrams == FiniteSet(d)
True
See Also
========
Diagram
"""
def __new__(cls, name, objects=EmptySet, commutative_diagrams=EmptySet):
if not name:
raise ValueError("A Category cannot have an empty name.")
if not isinstance(name, Str):
name = Str(name)
if not isinstance(objects, Class):
objects = Class(objects)
new_category = Basic.__new__(cls, name, objects,
FiniteSet(*commutative_diagrams))
return new_category
@property
def name(self):
"""
Returns the name of this category.
Examples
========
>>> from sympy.categories import Category
>>> K = Category("K")
>>> K.name
'K'
"""
return self.args[0].name
@property
def objects(self):
"""
Returns the class of objects of this category.
Examples
========
>>> from sympy.categories import Object, Category
>>> from sympy import FiniteSet
>>> A = Object("A")
>>> B = Object("B")
>>> K = Category("K", FiniteSet(A, B))
>>> K.objects
Class({Object("A"), Object("B")})
"""
return self.args[1]
@property
def commutative_diagrams(self):
"""
Returns the :class:`~.FiniteSet` of diagrams which are known to
be commutative in this category.
Examples
========
>>> from sympy.categories import Object, NamedMorphism, Diagram, Category
>>> from sympy import FiniteSet
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> d = Diagram([f, g])
>>> K = Category("K", commutative_diagrams=[d])
>>> K.commutative_diagrams == FiniteSet(d)
True
"""
return self.args[2]
def hom(self, A, B):
raise NotImplementedError(
"hom-sets are not implemented in Category.")
def all_morphisms(self):
raise NotImplementedError(
"Obtaining the class of morphisms is not implemented in Category.")
class Diagram(Basic):
r"""
Represents a diagram in a certain category.
Explanation
===========
Informally, a diagram is a collection of objects of a category and
certain morphisms between them. A diagram is still a monoid with
respect to morphism composition; i.e., identity morphisms, as well
as all composites of morphisms included in the diagram belong to
the diagram. For a more formal approach to this notion see
[Pare1970].
The components of composite morphisms are also added to the
diagram. No properties are assigned to such morphisms by default.
A commutative diagram is often accompanied by a statement of the
following kind: "if such morphisms with such properties exist,
then such morphisms which such properties exist and the diagram is
commutative". To represent this, an instance of :class:`Diagram`
includes a collection of morphisms which are the premises and
another collection of conclusions. ``premises`` and
``conclusions`` associate morphisms belonging to the corresponding
categories with the :class:`~.FiniteSet`'s of their properties.
The set of properties of a composite morphism is the intersection
of the sets of properties of its components. The domain and
codomain of a conclusion morphism should be among the domains and
codomains of the morphisms listed as the premises of a diagram.
No checks are carried out of whether the supplied object and
morphisms do belong to one and the same category.
Examples
========
>>> from sympy.categories import Object, NamedMorphism, Diagram
>>> from sympy import pprint, default_sort_key
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> d = Diagram([f, g])
>>> premises_keys = sorted(d.premises.keys(), key=default_sort_key)
>>> pprint(premises_keys, use_unicode=False)
[g*f:A-->C, id:A-->A, id:B-->B, id:C-->C, f:A-->B, g:B-->C]
>>> pprint(d.premises, use_unicode=False)
{g*f:A-->C: EmptySet, id:A-->A: EmptySet, id:B-->B: EmptySet,
id:C-->C: EmptySet, f:A-->B: EmptySet, g:B-->C: EmptySet}
>>> d = Diagram([f, g], {g * f: "unique"})
>>> pprint(d.conclusions,use_unicode=False)
{g*f:A-->C: {unique}}
References
==========
[Pare1970] B. Pareigis: Categories and functors. Academic Press, 1970.
"""
@staticmethod
def _set_dict_union(dictionary, key, value):
"""
If ``key`` is in ``dictionary``, set the new value of ``key``
to be the union between the old value and ``value``.
Otherwise, set the value of ``key`` to ``value.
Returns ``True`` if the key already was in the dictionary and
``False`` otherwise.
"""
if key in dictionary:
dictionary[key] = dictionary[key] | value
return True
else:
dictionary[key] = value
return False
@staticmethod
def _add_morphism_closure(morphisms, morphism, props, add_identities=True,
recurse_composites=True):
"""
Adds a morphism and its attributes to the supplied dictionary
``morphisms``. If ``add_identities`` is True, also adds the
identity morphisms for the domain and the codomain of
``morphism``.
"""
if not Diagram._set_dict_union(morphisms, morphism, props):
# We have just added a new morphism.
if isinstance(morphism, IdentityMorphism):
if props:
# Properties for identity morphisms don't really
# make sense, because very much is known about
# identity morphisms already, so much that they
# are trivial. Having properties for identity
# morphisms would only be confusing.
raise ValueError(
"Instances of IdentityMorphism cannot have properties.")
return
if add_identities:
empty = EmptySet
id_dom = IdentityMorphism(morphism.domain)
id_cod = IdentityMorphism(morphism.codomain)
Diagram._set_dict_union(morphisms, id_dom, empty)
Diagram._set_dict_union(morphisms, id_cod, empty)
for existing_morphism, existing_props in list(morphisms.items()):
new_props = existing_props & props
if morphism.domain == existing_morphism.codomain:
left = morphism * existing_morphism
Diagram._set_dict_union(morphisms, left, new_props)
if morphism.codomain == existing_morphism.domain:
right = existing_morphism * morphism
Diagram._set_dict_union(morphisms, right, new_props)
if isinstance(morphism, CompositeMorphism) and recurse_composites:
# This is a composite morphism, add its components as
# well.
empty = EmptySet
for component in morphism.components:
Diagram._add_morphism_closure(morphisms, component, empty,
add_identities)
def __new__(cls, *args):
"""
Construct a new instance of Diagram.
Explanation
===========
If no arguments are supplied, an empty diagram is created.
If at least an argument is supplied, ``args[0]`` is
interpreted as the premises of the diagram. If ``args[0]`` is
a list, it is interpreted as a list of :class:`Morphism`'s, in
which each :class:`Morphism` has an empty set of properties.
If ``args[0]`` is a Python dictionary or a :class:`Dict`, it
is interpreted as a dictionary associating to some
:class:`Morphism`'s some properties.
If at least two arguments are supplied ``args[1]`` is
interpreted as the conclusions of the diagram. The type of
``args[1]`` is interpreted in exactly the same way as the type
of ``args[0]``. If only one argument is supplied, the diagram
has no conclusions.
Examples
========
>>> from sympy.categories import Object, NamedMorphism
>>> from sympy.categories import IdentityMorphism, Diagram
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> d = Diagram([f, g])
>>> IdentityMorphism(A) in d.premises.keys()
True
>>> g * f in d.premises.keys()
True
>>> d = Diagram([f, g], {g * f: "unique"})
>>> d.conclusions[g * f]
{unique}
"""
premises = {}
conclusions = {}
# Here we will keep track of the objects which appear in the
# premises.
objects = EmptySet
if len(args) >= 1:
# We've got some premises in the arguments.
premises_arg = args[0]
if isinstance(premises_arg, list):
# The user has supplied a list of morphisms, none of
# which have any attributes.
empty = EmptySet
for morphism in premises_arg:
objects |= FiniteSet(morphism.domain, morphism.codomain)
Diagram._add_morphism_closure(premises, morphism, empty)
elif isinstance(premises_arg, (dict, Dict)):
# The user has supplied a dictionary of morphisms and
# their properties.
for morphism, props in premises_arg.items():
objects |= FiniteSet(morphism.domain, morphism.codomain)
Diagram._add_morphism_closure(
premises, morphism, FiniteSet(*props) if iterable(props) else FiniteSet(props))
if len(args) >= 2:
# We also have some conclusions.
conclusions_arg = args[1]
if isinstance(conclusions_arg, list):
# The user has supplied a list of morphisms, none of
# which have any attributes.
empty = EmptySet
for morphism in conclusions_arg:
# Check that no new objects appear in conclusions.
if ((sympify(objects.contains(morphism.domain)) is S.true) and
(sympify(objects.contains(morphism.codomain)) is S.true)):
# No need to add identities and recurse
# composites this time.
Diagram._add_morphism_closure(
conclusions, morphism, empty, add_identities=False,
recurse_composites=False)
elif isinstance(conclusions_arg, (dict, Dict)):
# The user has supplied a dictionary of morphisms and
# their properties.
for morphism, props in conclusions_arg.items():
# Check that no new objects appear in conclusions.
if (morphism.domain in objects) and \
(morphism.codomain in objects):
# No need to add identities and recurse
# composites this time.
Diagram._add_morphism_closure(
conclusions, morphism, FiniteSet(*props) if iterable(props) else FiniteSet(props),
add_identities=False, recurse_composites=False)
return Basic.__new__(cls, Dict(premises), Dict(conclusions), objects)
@property
def premises(self):
"""
Returns the premises of this diagram.
Examples
========
>>> from sympy.categories import Object, NamedMorphism
>>> from sympy.categories import IdentityMorphism, Diagram
>>> from sympy import pretty
>>> A = Object("A")
>>> B = Object("B")
>>> f = NamedMorphism(A, B, "f")
>>> id_A = IdentityMorphism(A)
>>> id_B = IdentityMorphism(B)
>>> d = Diagram([f])
>>> print(pretty(d.premises, use_unicode=False))
{id:A-->A: EmptySet, id:B-->B: EmptySet, f:A-->B: EmptySet}
"""
return self.args[0]
@property
def conclusions(self):
"""
Returns the conclusions of this diagram.
Examples
========
>>> from sympy.categories import Object, NamedMorphism
>>> from sympy.categories import IdentityMorphism, Diagram
>>> from sympy import FiniteSet
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> d = Diagram([f, g])
>>> IdentityMorphism(A) in d.premises.keys()
True
>>> g * f in d.premises.keys()
True
>>> d = Diagram([f, g], {g * f: "unique"})
>>> d.conclusions[g * f] == FiniteSet("unique")
True
"""
return self.args[1]
@property
def objects(self):
"""
Returns the :class:`~.FiniteSet` of objects that appear in this
diagram.
Examples
========
>>> from sympy.categories import Object, NamedMorphism, Diagram
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> d = Diagram([f, g])
>>> d.objects
{Object("A"), Object("B"), Object("C")}
"""
return self.args[2]
def hom(self, A, B):
"""
Returns a 2-tuple of sets of morphisms between objects ``A`` and
``B``: one set of morphisms listed as premises, and the other set
of morphisms listed as conclusions.
Examples
========
>>> from sympy.categories import Object, NamedMorphism, Diagram
>>> from sympy import pretty
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> d = Diagram([f, g], {g * f: "unique"})
>>> print(pretty(d.hom(A, C), use_unicode=False))
({g*f:A-->C}, {g*f:A-->C})
See Also
========
Object, Morphism
"""
premises = EmptySet
conclusions = EmptySet
for morphism in self.premises.keys():
if (morphism.domain == A) and (morphism.codomain == B):
premises |= FiniteSet(morphism)
for morphism in self.conclusions.keys():
if (morphism.domain == A) and (morphism.codomain == B):
conclusions |= FiniteSet(morphism)
return (premises, conclusions)
def is_subdiagram(self, diagram):
"""
Checks whether ``diagram`` is a subdiagram of ``self``.
Diagram `D'` is a subdiagram of `D` if all premises
(conclusions) of `D'` are contained in the premises
(conclusions) of `D`. The morphisms contained
both in `D'` and `D` should have the same properties for `D'`
to be a subdiagram of `D`.
Examples
========
>>> from sympy.categories import Object, NamedMorphism, Diagram
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> d = Diagram([f, g], {g * f: "unique"})
>>> d1 = Diagram([f])
>>> d.is_subdiagram(d1)
True
>>> d1.is_subdiagram(d)
False
"""
premises = all((m in self.premises) and
(diagram.premises[m] == self.premises[m])
for m in diagram.premises)
if not premises:
return False
conclusions = all((m in self.conclusions) and
(diagram.conclusions[m] == self.conclusions[m])
for m in diagram.conclusions)
# Premises is surely ``True`` here.
return conclusions
def subdiagram_from_objects(self, objects):
"""
If ``objects`` is a subset of the objects of ``self``, returns
a diagram which has as premises all those premises of ``self``
which have a domains and codomains in ``objects``, likewise
for conclusions. Properties are preserved.
Examples
========
>>> from sympy.categories import Object, NamedMorphism, Diagram
>>> from sympy import FiniteSet
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> d = Diagram([f, g], {f: "unique", g*f: "veryunique"})
>>> d1 = d.subdiagram_from_objects(FiniteSet(A, B))
>>> d1 == Diagram([f], {f: "unique"})
True
"""
if not objects.is_subset(self.objects):
raise ValueError(
"Supplied objects should all belong to the diagram.")
new_premises = {}
for morphism, props in self.premises.items():
if ((sympify(objects.contains(morphism.domain)) is S.true) and
(sympify(objects.contains(morphism.codomain)) is S.true)):
new_premises[morphism] = props
new_conclusions = {}
for morphism, props in self.conclusions.items():
if ((sympify(objects.contains(morphism.domain)) is S.true) and
(sympify(objects.contains(morphism.codomain)) is S.true)):
new_conclusions[morphism] = props
return Diagram(new_premises, new_conclusions)
PK ]ZZZ�i�_�s �s # sympy/categories/diagram_drawing.pyr"""
This module contains the functionality to arrange the nodes of a
diagram on an abstract grid, and then to produce a graphical
representation of the grid.
The currently supported back-ends are Xy-pic [Xypic].
Layout Algorithm
================
This section provides an overview of the algorithms implemented in
:class:`DiagramGrid` to lay out diagrams.
The first step of the algorithm is the removal composite and identity
morphisms which do not have properties in the supplied diagram. The
premises and conclusions of the diagram are then merged.
The generic layout algorithm begins with the construction of the
"skeleton" of the diagram. The skeleton is an undirected graph which
has the objects of the diagram as vertices and has an (undirected)
edge between each pair of objects between which there exist morphisms.
The direction of the morphisms does not matter at this stage. The
skeleton also includes an edge between each pair of vertices `A` and
`C` such that there exists an object `B` which is connected via
a morphism to `A`, and via a morphism to `C`.
The skeleton constructed in this way has the property that every
object is a vertex of a triangle formed by three edges of the
skeleton. This property lies at the base of the generic layout
algorithm.
After the skeleton has been constructed, the algorithm lists all
triangles which can be formed. Note that some triangles will not have
all edges corresponding to morphisms which will actually be drawn.
Triangles which have only one edge or less which will actually be
drawn are immediately discarded.
The list of triangles is sorted according to the number of edges which
correspond to morphisms, then the triangle with the least number of such
edges is selected. One of such edges is picked and the corresponding
objects are placed horizontally, on a grid. This edge is recorded to
be in the fringe. The algorithm then finds a "welding" of a triangle
to the fringe. A welding is an edge in the fringe where a triangle
could be attached. If the algorithm succeeds in finding such a
welding, it adds to the grid that vertex of the triangle which was not
yet included in any edge in the fringe and records the two new edges in
the fringe. This process continues iteratively until all objects of
the diagram has been placed or until no more weldings can be found.
An edge is only removed from the fringe when a welding to this edge
has been found, and there is no room around this edge to place
another vertex.
When no more weldings can be found, but there are still triangles
left, the algorithm searches for a possibility of attaching one of the
remaining triangles to the existing structure by a vertex. If such a
possibility is found, the corresponding edge of the found triangle is
placed in the found space and the iterative process of welding
triangles restarts.
When logical groups are supplied, each of these groups is laid out
independently. Then a diagram is constructed in which groups are
objects and any two logical groups between which there exist morphisms
are connected via a morphism. This diagram is laid out. Finally,
the grid which includes all objects of the initial diagram is
constructed by replacing the cells which contain logical groups with
the corresponding laid out grids, and by correspondingly expanding the
rows and columns.
The sequential layout algorithm begins by constructing the
underlying undirected graph defined by the morphisms obtained after
simplifying premises and conclusions and merging them (see above).
The vertex with the minimal degree is then picked up and depth-first
search is started from it. All objects which are located at distance
`n` from the root in the depth-first search tree, are positioned in
the `n`-th column of the resulting grid. The sequential layout will
therefore attempt to lay the objects out along a line.
References
==========
.. [Xypic] https://xy-pic.sourceforge.net/
"""
from sympy.categories import (CompositeMorphism, IdentityMorphism,
NamedMorphism, Diagram)
from sympy.core import Dict, Symbol, default_sort_key
from sympy.printing.latex import latex
from sympy.sets import FiniteSet
from sympy.utilities.iterables import iterable
from sympy.utilities.decorator import doctest_depends_on
from itertools import chain
__doctest_requires__ = {('preview_diagram',): 'pyglet'}
class _GrowableGrid:
"""
Holds a growable grid of objects.
Explanation
===========
It is possible to append or prepend a row or a column to the grid
using the corresponding methods. Prepending rows or columns has
the effect of changing the coordinates of the already existing
elements.
This class currently represents a naive implementation of the
functionality with little attempt at optimisation.
"""
def __init__(self, width, height):
self._width = width
self._height = height
self._array = [[None for j in range(width)] for i in range(height)]
@property
def width(self):
return self._width
@property
def height(self):
return self._height
def __getitem__(self, i_j):
"""
Returns the element located at in the i-th line and j-th
column.
"""
i, j = i_j
return self._array[i][j]
def __setitem__(self, i_j, newvalue):
"""
Sets the element located at in the i-th line and j-th
column.
"""
i, j = i_j
self._array[i][j] = newvalue
def append_row(self):
"""
Appends an empty row to the grid.
"""
self._height += 1
self._array.append([None for j in range(self._width)])
def append_column(self):
"""
Appends an empty column to the grid.
"""
self._width += 1
for i in range(self._height):
self._array[i].append(None)
def prepend_row(self):
"""
Prepends the grid with an empty row.
"""
self._height += 1
self._array.insert(0, [None for j in range(self._width)])
def prepend_column(self):
"""
Prepends the grid with an empty column.
"""
self._width += 1
for i in range(self._height):
self._array[i].insert(0, None)
class DiagramGrid:
r"""
Constructs and holds the fitting of the diagram into a grid.
Explanation
===========
The mission of this class is to analyse the structure of the
supplied diagram and to place its objects on a grid such that,
when the objects and the morphisms are actually drawn, the diagram
would be "readable", in the sense that there will not be many
intersections of moprhisms. This class does not perform any
actual drawing. It does strive nevertheless to offer sufficient
metadata to draw a diagram.
Consider the following simple diagram.
>>> from sympy.categories import Object, NamedMorphism
>>> from sympy.categories import Diagram, DiagramGrid
>>> from sympy import pprint
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> diagram = Diagram([f, g])
The simplest way to have a diagram laid out is the following:
>>> grid = DiagramGrid(diagram)
>>> (grid.width, grid.height)
(2, 2)
>>> pprint(grid)
A B
<BLANKLINE>
C
Sometimes one sees the diagram as consisting of logical groups.
One can advise ``DiagramGrid`` as to such groups by employing the
``groups`` keyword argument.
Consider the following diagram:
>>> D = Object("D")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> h = NamedMorphism(D, A, "h")
>>> k = NamedMorphism(D, B, "k")
>>> diagram = Diagram([f, g, h, k])
Lay it out with generic layout:
>>> grid = DiagramGrid(diagram)
>>> pprint(grid)
A B D
<BLANKLINE>
C
Now, we can group the objects `A` and `D` to have them near one
another:
>>> grid = DiagramGrid(diagram, groups=[[A, D], B, C])
>>> pprint(grid)
B C
<BLANKLINE>
A D
Note how the positioning of the other objects changes.
Further indications can be supplied to the constructor of
:class:`DiagramGrid` using keyword arguments. The currently
supported hints are explained in the following paragraphs.
:class:`DiagramGrid` does not automatically guess which layout
would suit the supplied diagram better. Consider, for example,
the following linear diagram:
>>> E = Object("E")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> h = NamedMorphism(C, D, "h")
>>> i = NamedMorphism(D, E, "i")
>>> diagram = Diagram([f, g, h, i])
When laid out with the generic layout, it does not get to look
linear:
>>> grid = DiagramGrid(diagram)
>>> pprint(grid)
A B
<BLANKLINE>
C D
<BLANKLINE>
E
To get it laid out in a line, use ``layout="sequential"``:
>>> grid = DiagramGrid(diagram, layout="sequential")
>>> pprint(grid)
A B C D E
One may sometimes need to transpose the resulting layout. While
this can always be done by hand, :class:`DiagramGrid` provides a
hint for that purpose:
>>> grid = DiagramGrid(diagram, layout="sequential", transpose=True)
>>> pprint(grid)
A
<BLANKLINE>
B
<BLANKLINE>
C
<BLANKLINE>
D
<BLANKLINE>
E
Separate hints can also be provided for each group. For an
example, refer to ``tests/test_drawing.py``, and see the different
ways in which the five lemma [FiveLemma] can be laid out.
See Also
========
Diagram
References
==========
.. [FiveLemma] https://en.wikipedia.org/wiki/Five_lemma
"""
@staticmethod
def _simplify_morphisms(morphisms):
"""
Given a dictionary mapping morphisms to their properties,
returns a new dictionary in which there are no morphisms which
do not have properties, and which are compositions of other
morphisms included in the dictionary. Identities are dropped
as well.
"""
newmorphisms = {}
for morphism, props in morphisms.items():
if isinstance(morphism, CompositeMorphism) and not props:
continue
elif isinstance(morphism, IdentityMorphism):
continue
else:
newmorphisms[morphism] = props
return newmorphisms
@staticmethod
def _merge_premises_conclusions(premises, conclusions):
"""
Given two dictionaries of morphisms and their properties,
produces a single dictionary which includes elements from both
dictionaries. If a morphism has some properties in premises
and also in conclusions, the properties in conclusions take
priority.
"""
return dict(chain(premises.items(), conclusions.items()))
@staticmethod
def _juxtapose_edges(edge1, edge2):
"""
If ``edge1`` and ``edge2`` have precisely one common endpoint,
returns an edge which would form a triangle with ``edge1`` and
``edge2``.
If ``edge1`` and ``edge2`` do not have a common endpoint,
returns ``None``.
If ``edge1`` and ``edge`` are the same edge, returns ``None``.
"""
intersection = edge1 & edge2
if len(intersection) != 1:
# The edges either have no common points or are equal.
return None
# The edges have a common endpoint. Extract the different
# endpoints and set up the new edge.
return (edge1 - intersection) | (edge2 - intersection)
@staticmethod
def _add_edge_append(dictionary, edge, elem):
"""
If ``edge`` is not in ``dictionary``, adds ``edge`` to the
dictionary and sets its value to ``[elem]``. Otherwise
appends ``elem`` to the value of existing entry.
Note that edges are undirected, thus `(A, B) = (B, A)`.
"""
if edge in dictionary:
dictionary[edge].append(elem)
else:
dictionary[edge] = [elem]
@staticmethod
def _build_skeleton(morphisms):
"""
Creates a dictionary which maps edges to corresponding
morphisms. Thus for a morphism `f:A\rightarrow B`, the edge
`(A, B)` will be associated with `f`. This function also adds
to the list those edges which are formed by juxtaposition of
two edges already in the list. These new edges are not
associated with any morphism and are only added to assure that
the diagram can be decomposed into triangles.
"""
edges = {}
# Create edges for morphisms.
for morphism in morphisms:
DiagramGrid._add_edge_append(
edges, frozenset([morphism.domain, morphism.codomain]), morphism)
# Create new edges by juxtaposing existing edges.
edges1 = dict(edges)
for w in edges1:
for v in edges1:
wv = DiagramGrid._juxtapose_edges(w, v)
if wv and wv not in edges:
edges[wv] = []
return edges
@staticmethod
def _list_triangles(edges):
"""
Builds the set of triangles formed by the supplied edges. The
triangles are arbitrary and need not be commutative. A
triangle is a set that contains all three of its sides.
"""
triangles = set()
for w in edges:
for v in edges:
wv = DiagramGrid._juxtapose_edges(w, v)
if wv and wv in edges:
triangles.add(frozenset([w, v, wv]))
return triangles
@staticmethod
def _drop_redundant_triangles(triangles, skeleton):
"""
Returns a list which contains only those triangles who have
morphisms associated with at least two edges.
"""
return [tri for tri in triangles
if len([e for e in tri if skeleton[e]]) >= 2]
@staticmethod
def _morphism_length(morphism):
"""
Returns the length of a morphism. The length of a morphism is
the number of components it consists of. A non-composite
morphism is of length 1.
"""
if isinstance(morphism, CompositeMorphism):
return len(morphism.components)
else:
return 1
@staticmethod
def _compute_triangle_min_sizes(triangles, edges):
r"""
Returns a dictionary mapping triangles to their minimal sizes.
The minimal size of a triangle is the sum of maximal lengths
of morphisms associated to the sides of the triangle. The
length of a morphism is the number of components it consists
of. A non-composite morphism is of length 1.
Sorting triangles by this metric attempts to address two
aspects of layout. For triangles with only simple morphisms
in the edge, this assures that triangles with all three edges
visible will get typeset after triangles with less visible
edges, which sometimes minimizes the necessity in diagonal
arrows. For triangles with composite morphisms in the edges,
this assures that objects connected with shorter morphisms
will be laid out first, resulting the visual proximity of
those objects which are connected by shorter morphisms.
"""
triangle_sizes = {}
for triangle in triangles:
size = 0
for e in triangle:
morphisms = edges[e]
if morphisms:
size += max(DiagramGrid._morphism_length(m)
for m in morphisms)
triangle_sizes[triangle] = size
return triangle_sizes
@staticmethod
def _triangle_objects(triangle):
"""
Given a triangle, returns the objects included in it.
"""
# A triangle is a frozenset of three two-element frozensets
# (the edges). This chains the three edges together and
# creates a frozenset from the iterator, thus producing a
# frozenset of objects of the triangle.
return frozenset(chain(*tuple(triangle)))
@staticmethod
def _other_vertex(triangle, edge):
"""
Given a triangle and an edge of it, returns the vertex which
opposes the edge.
"""
# This gets the set of objects of the triangle and then
# subtracts the set of objects employed in ``edge`` to get the
# vertex opposite to ``edge``.
return list(DiagramGrid._triangle_objects(triangle) - set(edge))[0]
@staticmethod
def _empty_point(pt, grid):
"""
Checks if the cell at coordinates ``pt`` is either empty or
out of the bounds of the grid.
"""
if (pt[0] < 0) or (pt[1] < 0) or \
(pt[0] >= grid.height) or (pt[1] >= grid.width):
return True
return grid[pt] is None
@staticmethod
def _put_object(coords, obj, grid, fringe):
"""
Places an object at the coordinate ``cords`` in ``grid``,
growing the grid and updating ``fringe``, if necessary.
Returns (0, 0) if no row or column has been prepended, (1, 0)
if a row was prepended, (0, 1) if a column was prepended and
(1, 1) if both a column and a row were prepended.
"""
(i, j) = coords
offset = (0, 0)
if i == -1:
grid.prepend_row()
i = 0
offset = (1, 0)
for k in range(len(fringe)):
((i1, j1), (i2, j2)) = fringe[k]
fringe[k] = ((i1 + 1, j1), (i2 + 1, j2))
elif i == grid.height:
grid.append_row()
if j == -1:
j = 0
offset = (offset[0], 1)
grid.prepend_column()
for k in range(len(fringe)):
((i1, j1), (i2, j2)) = fringe[k]
fringe[k] = ((i1, j1 + 1), (i2, j2 + 1))
elif j == grid.width:
grid.append_column()
grid[i, j] = obj
return offset
@staticmethod
def _choose_target_cell(pt1, pt2, edge, obj, skeleton, grid):
"""
Given two points, ``pt1`` and ``pt2``, and the welding edge
``edge``, chooses one of the two points to place the opposing
vertex ``obj`` of the triangle. If neither of this points
fits, returns ``None``.
"""
pt1_empty = DiagramGrid._empty_point(pt1, grid)
pt2_empty = DiagramGrid._empty_point(pt2, grid)
if pt1_empty and pt2_empty:
# Both cells are empty. Of these two, choose that cell
# which will assure that a visible edge of the triangle
# will be drawn perpendicularly to the current welding
# edge.
A = grid[edge[0]]
if skeleton.get(frozenset([A, obj])):
return pt1
else:
return pt2
if pt1_empty:
return pt1
elif pt2_empty:
return pt2
else:
return None
@staticmethod
def _find_triangle_to_weld(triangles, fringe, grid):
"""
Finds, if possible, a triangle and an edge in the ``fringe`` to
which the triangle could be attached. Returns the tuple
containing the triangle and the index of the corresponding
edge in the ``fringe``.
This function relies on the fact that objects are unique in
the diagram.
"""
for triangle in triangles:
for (a, b) in fringe:
if frozenset([grid[a], grid[b]]) in triangle:
return (triangle, (a, b))
return None
@staticmethod
def _weld_triangle(tri, welding_edge, fringe, grid, skeleton):
"""
If possible, welds the triangle ``tri`` to ``fringe`` and
returns ``False``. If this method encounters a degenerate
situation in the fringe and corrects it such that a restart of
the search is required, it returns ``True`` (which means that
a restart in finding triangle weldings is required).
A degenerate situation is a situation when an edge listed in
the fringe does not belong to the visual boundary of the
diagram.
"""
a, b = welding_edge
target_cell = None
obj = DiagramGrid._other_vertex(tri, (grid[a], grid[b]))
# We now have a triangle and an edge where it can be welded to
# the fringe. Decide where to place the other vertex of the
# triangle and check for degenerate situations en route.
if (abs(a[0] - b[0]) == 1) and (abs(a[1] - b[1]) == 1):
# A diagonal edge.
target_cell = (a[0], b[1])
if grid[target_cell]:
# That cell is already occupied.
target_cell = (b[0], a[1])
if grid[target_cell]:
# Degenerate situation, this edge is not
# on the actual fringe. Correct the
# fringe and go on.
fringe.remove((a, b))
return True
elif a[0] == b[0]:
# A horizontal edge. We first attempt to build the
# triangle in the downward direction.
down_left = a[0] + 1, a[1]
down_right = a[0] + 1, b[1]
target_cell = DiagramGrid._choose_target_cell(
down_left, down_right, (a, b), obj, skeleton, grid)
if not target_cell:
# No room below this edge. Check above.
up_left = a[0] - 1, a[1]
up_right = a[0] - 1, b[1]
target_cell = DiagramGrid._choose_target_cell(
up_left, up_right, (a, b), obj, skeleton, grid)
if not target_cell:
# This edge is not in the fringe, remove it
# and restart.
fringe.remove((a, b))
return True
elif a[1] == b[1]:
# A vertical edge. We will attempt to place the other
# vertex of the triangle to the right of this edge.
right_up = a[0], a[1] + 1
right_down = b[0], a[1] + 1
target_cell = DiagramGrid._choose_target_cell(
right_up, right_down, (a, b), obj, skeleton, grid)
if not target_cell:
# No room to the left. See what's to the right.
left_up = a[0], a[1] - 1
left_down = b[0], a[1] - 1
target_cell = DiagramGrid._choose_target_cell(
left_up, left_down, (a, b), obj, skeleton, grid)
if not target_cell:
# This edge is not in the fringe, remove it
# and restart.
fringe.remove((a, b))
return True
# We now know where to place the other vertex of the
# triangle.
offset = DiagramGrid._put_object(target_cell, obj, grid, fringe)
# Take care of the displacement of coordinates if a row or
# a column was prepended.
target_cell = (target_cell[0] + offset[0],
target_cell[1] + offset[1])
a = (a[0] + offset[0], a[1] + offset[1])
b = (b[0] + offset[0], b[1] + offset[1])
fringe.extend([(a, target_cell), (b, target_cell)])
# No restart is required.
return False
@staticmethod
def _triangle_key(tri, triangle_sizes):
"""
Returns a key for the supplied triangle. It should be the
same independently of the hash randomisation.
"""
objects = sorted(
DiagramGrid._triangle_objects(tri), key=default_sort_key)
return (triangle_sizes[tri], default_sort_key(objects))
@staticmethod
def _pick_root_edge(tri, skeleton):
"""
For a given triangle always picks the same root edge. The
root edge is the edge that will be placed first on the grid.
"""
candidates = [sorted(e, key=default_sort_key)
for e in tri if skeleton[e]]
sorted_candidates = sorted(candidates, key=default_sort_key)
# Don't forget to assure the proper ordering of the vertices
# in this edge.
return tuple(sorted(sorted_candidates[0], key=default_sort_key))
@staticmethod
def _drop_irrelevant_triangles(triangles, placed_objects):
"""
Returns only those triangles whose set of objects is not
completely included in ``placed_objects``.
"""
return [tri for tri in triangles if not placed_objects.issuperset(
DiagramGrid._triangle_objects(tri))]
@staticmethod
def _grow_pseudopod(triangles, fringe, grid, skeleton, placed_objects):
"""
Starting from an object in the existing structure on the ``grid``,
adds an edge to which a triangle from ``triangles`` could be
welded. If this method has found a way to do so, it returns
the object it has just added.
This method should be applied when ``_weld_triangle`` cannot
find weldings any more.
"""
for i in range(grid.height):
for j in range(grid.width):
obj = grid[i, j]
if not obj:
continue
# Here we need to choose a triangle which has only
# ``obj`` in common with the existing structure. The
# situations when this is not possible should be
# handled elsewhere.
def good_triangle(tri):
objs = DiagramGrid._triangle_objects(tri)
return obj in objs and \
placed_objects & (objs - {obj}) == set()
tris = [tri for tri in triangles if good_triangle(tri)]
if not tris:
# This object is not interesting.
continue
# Pick the "simplest" of the triangles which could be
# attached. Remember that the list of triangles is
# sorted according to their "simplicity" (see
# _compute_triangle_min_sizes for the metric).
#
# Note that ``tris`` are sequentially built from
# ``triangles``, so we don't have to worry about hash
# randomisation.
tri = tris[0]
# We have found a triangle which could be attached to
# the existing structure by a vertex.
candidates = sorted([e for e in tri if skeleton[e]],
key=lambda e: FiniteSet(*e).sort_key())
edges = [e for e in candidates if obj in e]
# Note that a meaningful edge (i.e., and edge that is
# associated with a morphism) containing ``obj``
# always exists. That's because all triangles are
# guaranteed to have at least two meaningful edges.
# See _drop_redundant_triangles.
# Get the object at the other end of the edge.
edge = edges[0]
other_obj = tuple(edge - frozenset([obj]))[0]
# Now check for free directions. When checking for
# free directions, prefer the horizontal and vertical
# directions.
neighbours = [(i - 1, j), (i, j + 1), (i + 1, j), (i, j - 1),
(i - 1, j - 1), (i - 1, j + 1), (i + 1, j - 1), (i + 1, j + 1)]
for pt in neighbours:
if DiagramGrid._empty_point(pt, grid):
# We have a found a place to grow the
# pseudopod into.
offset = DiagramGrid._put_object(
pt, other_obj, grid, fringe)
i += offset[0]
j += offset[1]
pt = (pt[0] + offset[0], pt[1] + offset[1])
fringe.append(((i, j), pt))
return other_obj
# This diagram is actually cooler that I can handle. Fail cowardly.
return None
@staticmethod
def _handle_groups(diagram, groups, merged_morphisms, hints):
"""
Given the slightly preprocessed morphisms of the diagram,
produces a grid laid out according to ``groups``.
If a group has hints, it is laid out with those hints only,
without any influence from ``hints``. Otherwise, it is laid
out with ``hints``.
"""
def lay_out_group(group, local_hints):
"""
If ``group`` is a set of objects, uses a ``DiagramGrid``
to lay it out and returns the grid. Otherwise returns the
object (i.e., ``group``). If ``local_hints`` is not
empty, it is supplied to ``DiagramGrid`` as the dictionary
of hints. Otherwise, the ``hints`` argument of
``_handle_groups`` is used.
"""
if isinstance(group, FiniteSet):
# Set up the corresponding object-to-group
# mappings.
for obj in group:
obj_groups[obj] = group
# Lay out the current group.
if local_hints:
groups_grids[group] = DiagramGrid(
diagram.subdiagram_from_objects(group), **local_hints)
else:
groups_grids[group] = DiagramGrid(
diagram.subdiagram_from_objects(group), **hints)
else:
obj_groups[group] = group
def group_to_finiteset(group):
"""
Converts ``group`` to a :class:``FiniteSet`` if it is an
iterable.
"""
if iterable(group):
return FiniteSet(*group)
else:
return group
obj_groups = {}
groups_grids = {}
# We would like to support various containers to represent
# groups. To achieve that, before laying each group out, it
# should be converted to a FiniteSet, because that is what the
# following code expects.
if isinstance(groups, (dict, Dict)):
finiteset_groups = {}
for group, local_hints in groups.items():
finiteset_group = group_to_finiteset(group)
finiteset_groups[finiteset_group] = local_hints
lay_out_group(group, local_hints)
groups = finiteset_groups
else:
finiteset_groups = []
for group in groups:
finiteset_group = group_to_finiteset(group)
finiteset_groups.append(finiteset_group)
lay_out_group(finiteset_group, None)
groups = finiteset_groups
new_morphisms = []
for morphism in merged_morphisms:
dom = obj_groups[morphism.domain]
cod = obj_groups[morphism.codomain]
# Note that we are not really interested in morphisms
# which do not employ two different groups, because
# these do not influence the layout.
if dom != cod:
# These are essentially unnamed morphisms; they are
# not going to mess in the final layout. By giving
# them the same names, we avoid unnecessary
# duplicates.
new_morphisms.append(NamedMorphism(dom, cod, "dummy"))
# Lay out the new diagram. Since these are dummy morphisms,
# properties and conclusions are irrelevant.
top_grid = DiagramGrid(Diagram(new_morphisms))
# We now have to substitute the groups with the corresponding
# grids, laid out at the beginning of this function. Compute
# the size of each row and column in the grid, so that all
# nested grids fit.
def group_size(group):
"""
For the supplied group (or object, eventually), returns
the size of the cell that will hold this group (object).
"""
if group in groups_grids:
grid = groups_grids[group]
return (grid.height, grid.width)
else:
return (1, 1)
row_heights = [max(group_size(top_grid[i, j])[0]
for j in range(top_grid.width))
for i in range(top_grid.height)]
column_widths = [max(group_size(top_grid[i, j])[1]
for i in range(top_grid.height))
for j in range(top_grid.width)]
grid = _GrowableGrid(sum(column_widths), sum(row_heights))
real_row = 0
real_column = 0
for logical_row in range(top_grid.height):
for logical_column in range(top_grid.width):
obj = top_grid[logical_row, logical_column]
if obj in groups_grids:
# This is a group. Copy the corresponding grid in
# place.
local_grid = groups_grids[obj]
for i in range(local_grid.height):
for j in range(local_grid.width):
grid[real_row + i,
real_column + j] = local_grid[i, j]
else:
# This is an object. Just put it there.
grid[real_row, real_column] = obj
real_column += column_widths[logical_column]
real_column = 0
real_row += row_heights[logical_row]
return grid
@staticmethod
def _generic_layout(diagram, merged_morphisms):
"""
Produces the generic layout for the supplied diagram.
"""
all_objects = set(diagram.objects)
if len(all_objects) == 1:
# There only one object in the diagram, just put in on 1x1
# grid.
grid = _GrowableGrid(1, 1)
grid[0, 0] = tuple(all_objects)[0]
return grid
skeleton = DiagramGrid._build_skeleton(merged_morphisms)
grid = _GrowableGrid(2, 1)
if len(skeleton) == 1:
# This diagram contains only one morphism. Draw it
# horizontally.
objects = sorted(all_objects, key=default_sort_key)
grid[0, 0] = objects[0]
grid[0, 1] = objects[1]
return grid
triangles = DiagramGrid._list_triangles(skeleton)
triangles = DiagramGrid._drop_redundant_triangles(triangles, skeleton)
triangle_sizes = DiagramGrid._compute_triangle_min_sizes(
triangles, skeleton)
triangles = sorted(triangles, key=lambda tri:
DiagramGrid._triangle_key(tri, triangle_sizes))
# Place the first edge on the grid.
root_edge = DiagramGrid._pick_root_edge(triangles[0], skeleton)
grid[0, 0], grid[0, 1] = root_edge
fringe = [((0, 0), (0, 1))]
# Record which objects we now have on the grid.
placed_objects = set(root_edge)
while placed_objects != all_objects:
welding = DiagramGrid._find_triangle_to_weld(
triangles, fringe, grid)
if welding:
(triangle, welding_edge) = welding
restart_required = DiagramGrid._weld_triangle(
triangle, welding_edge, fringe, grid, skeleton)
if restart_required:
continue
placed_objects.update(
DiagramGrid._triangle_objects(triangle))
else:
# No more weldings found. Try to attach triangles by
# vertices.
new_obj = DiagramGrid._grow_pseudopod(
triangles, fringe, grid, skeleton, placed_objects)
if not new_obj:
# No more triangles can be attached, not even by
# the edge. We will set up a new diagram out of
# what has been left, laid it out independently,
# and then attach it to this one.
remaining_objects = all_objects - placed_objects
remaining_diagram = diagram.subdiagram_from_objects(
FiniteSet(*remaining_objects))
remaining_grid = DiagramGrid(remaining_diagram)
# Now, let's glue ``remaining_grid`` to ``grid``.
final_width = grid.width + remaining_grid.width
final_height = max(grid.height, remaining_grid.height)
final_grid = _GrowableGrid(final_width, final_height)
for i in range(grid.width):
for j in range(grid.height):
final_grid[i, j] = grid[i, j]
start_j = grid.width
for i in range(remaining_grid.height):
for j in range(remaining_grid.width):
final_grid[i, start_j + j] = remaining_grid[i, j]
return final_grid
placed_objects.add(new_obj)
triangles = DiagramGrid._drop_irrelevant_triangles(
triangles, placed_objects)
return grid
@staticmethod
def _get_undirected_graph(objects, merged_morphisms):
"""
Given the objects and the relevant morphisms of a diagram,
returns the adjacency lists of the underlying undirected
graph.
"""
adjlists = {}
for obj in objects:
adjlists[obj] = []
for morphism in merged_morphisms:
adjlists[morphism.domain].append(morphism.codomain)
adjlists[morphism.codomain].append(morphism.domain)
# Assure that the objects in the adjacency list are always in
# the same order.
for obj in adjlists.keys():
adjlists[obj].sort(key=default_sort_key)
return adjlists
@staticmethod
def _sequential_layout(diagram, merged_morphisms):
r"""
Lays out the diagram in "sequential" layout. This method
will attempt to produce a result as close to a line as
possible. For linear diagrams, the result will actually be a
line.
"""
objects = diagram.objects
sorted_objects = sorted(objects, key=default_sort_key)
# Set up the adjacency lists of the underlying undirected
# graph of ``merged_morphisms``.
adjlists = DiagramGrid._get_undirected_graph(objects, merged_morphisms)
root = min(sorted_objects, key=lambda x: len(adjlists[x]))
grid = _GrowableGrid(1, 1)
grid[0, 0] = root
placed_objects = {root}
def place_objects(pt, placed_objects):
"""
Does depth-first search in the underlying graph of the
diagram and places the objects en route.
"""
# We will start placing new objects from here.
new_pt = (pt[0], pt[1] + 1)
for adjacent_obj in adjlists[grid[pt]]:
if adjacent_obj in placed_objects:
# This object has already been placed.
continue
DiagramGrid._put_object(new_pt, adjacent_obj, grid, [])
placed_objects.add(adjacent_obj)
placed_objects.update(place_objects(new_pt, placed_objects))
new_pt = (new_pt[0] + 1, new_pt[1])
return placed_objects
place_objects((0, 0), placed_objects)
return grid
@staticmethod
def _drop_inessential_morphisms(merged_morphisms):
r"""
Removes those morphisms which should appear in the diagram,
but which have no relevance to object layout.
Currently this removes "loop" morphisms: the non-identity
morphisms with the same domains and codomains.
"""
morphisms = [m for m in merged_morphisms if m.domain != m.codomain]
return morphisms
@staticmethod
def _get_connected_components(objects, merged_morphisms):
"""
Given a container of morphisms, returns a list of connected
components formed by these morphisms. A connected component
is represented by a diagram consisting of the corresponding
morphisms.
"""
component_index = {}
for o in objects:
component_index[o] = None
# Get the underlying undirected graph of the diagram.
adjlist = DiagramGrid._get_undirected_graph(objects, merged_morphisms)
def traverse_component(object, current_index):
"""
Does a depth-first search traversal of the component
containing ``object``.
"""
component_index[object] = current_index
for o in adjlist[object]:
if component_index[o] is None:
traverse_component(o, current_index)
# Traverse all components.
current_index = 0
for o in adjlist:
if component_index[o] is None:
traverse_component(o, current_index)
current_index += 1
# List the objects of the components.
component_objects = [[] for i in range(current_index)]
for o, idx in component_index.items():
component_objects[idx].append(o)
# Finally, list the morphisms belonging to each component.
#
# Note: If some objects are isolated, they will not get any
# morphisms at this stage, and since the layout algorithm
# relies, we are essentially going to lose this object.
# Therefore, check if there are isolated objects and, for each
# of them, provide the trivial identity morphism. It will get
# discarded later, but the object will be there.
component_morphisms = []
for component in component_objects:
current_morphisms = {}
for m in merged_morphisms:
if (m.domain in component) and (m.codomain in component):
current_morphisms[m] = merged_morphisms[m]
if len(component) == 1:
# Let's add an identity morphism, for the sake of
# surely having morphisms in this component.
current_morphisms[IdentityMorphism(component[0])] = FiniteSet()
component_morphisms.append(Diagram(current_morphisms))
return component_morphisms
def __init__(self, diagram, groups=None, **hints):
premises = DiagramGrid._simplify_morphisms(diagram.premises)
conclusions = DiagramGrid._simplify_morphisms(diagram.conclusions)
all_merged_morphisms = DiagramGrid._merge_premises_conclusions(
premises, conclusions)
merged_morphisms = DiagramGrid._drop_inessential_morphisms(
all_merged_morphisms)
# Store the merged morphisms for later use.
self._morphisms = all_merged_morphisms
components = DiagramGrid._get_connected_components(
diagram.objects, all_merged_morphisms)
if groups and (groups != diagram.objects):
# Lay out the diagram according to the groups.
self._grid = DiagramGrid._handle_groups(
diagram, groups, merged_morphisms, hints)
elif len(components) > 1:
# Note that we check for connectedness _before_ checking
# the layout hints because the layout strategies don't
# know how to deal with disconnected diagrams.
# The diagram is disconnected. Lay out the components
# independently.
grids = []
# Sort the components to eventually get the grids arranged
# in a fixed, hash-independent order.
components = sorted(components, key=default_sort_key)
for component in components:
grid = DiagramGrid(component, **hints)
grids.append(grid)
# Throw the grids together, in a line.
total_width = sum(g.width for g in grids)
total_height = max(g.height for g in grids)
grid = _GrowableGrid(total_width, total_height)
start_j = 0
for g in grids:
for i in range(g.height):
for j in range(g.width):
grid[i, start_j + j] = g[i, j]
start_j += g.width
self._grid = grid
elif "layout" in hints:
if hints["layout"] == "sequential":
self._grid = DiagramGrid._sequential_layout(
diagram, merged_morphisms)
else:
self._grid = DiagramGrid._generic_layout(diagram, merged_morphisms)
if hints.get("transpose"):
# Transpose the resulting grid.
grid = _GrowableGrid(self._grid.height, self._grid.width)
for i in range(self._grid.height):
for j in range(self._grid.width):
grid[j, i] = self._grid[i, j]
self._grid = grid
@property
def width(self):
"""
Returns the number of columns in this diagram layout.
Examples
========
>>> from sympy.categories import Object, NamedMorphism
>>> from sympy.categories import Diagram, DiagramGrid
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> diagram = Diagram([f, g])
>>> grid = DiagramGrid(diagram)
>>> grid.width
2
"""
return self._grid.width
@property
def height(self):
"""
Returns the number of rows in this diagram layout.
Examples
========
>>> from sympy.categories import Object, NamedMorphism
>>> from sympy.categories import Diagram, DiagramGrid
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> diagram = Diagram([f, g])
>>> grid = DiagramGrid(diagram)
>>> grid.height
2
"""
return self._grid.height
def __getitem__(self, i_j):
"""
Returns the object placed in the row ``i`` and column ``j``.
The indices are 0-based.
Examples
========
>>> from sympy.categories import Object, NamedMorphism
>>> from sympy.categories import Diagram, DiagramGrid
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> diagram = Diagram([f, g])
>>> grid = DiagramGrid(diagram)
>>> (grid[0, 0], grid[0, 1])
(Object("A"), Object("B"))
>>> (grid[1, 0], grid[1, 1])
(None, Object("C"))
"""
i, j = i_j
return self._grid[i, j]
@property
def morphisms(self):
"""
Returns those morphisms (and their properties) which are
sufficiently meaningful to be drawn.
Examples
========
>>> from sympy.categories import Object, NamedMorphism
>>> from sympy.categories import Diagram, DiagramGrid
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> diagram = Diagram([f, g])
>>> grid = DiagramGrid(diagram)
>>> grid.morphisms
{NamedMorphism(Object("A"), Object("B"), "f"): EmptySet,
NamedMorphism(Object("B"), Object("C"), "g"): EmptySet}
"""
return self._morphisms
def __str__(self):
"""
Produces a string representation of this class.
This method returns a string representation of the underlying
list of lists of objects.
Examples
========
>>> from sympy.categories import Object, NamedMorphism
>>> from sympy.categories import Diagram, DiagramGrid
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> diagram = Diagram([f, g])
>>> grid = DiagramGrid(diagram)
>>> print(grid)
[[Object("A"), Object("B")],
[None, Object("C")]]
"""
return repr(self._grid._array)
class ArrowStringDescription:
r"""
Stores the information necessary for producing an Xy-pic
description of an arrow.
The principal goal of this class is to abstract away the string
representation of an arrow and to also provide the functionality
to produce the actual Xy-pic string.
``unit`` sets the unit which will be used to specify the amount of
curving and other distances. ``horizontal_direction`` should be a
string of ``"r"`` or ``"l"`` specifying the horizontal offset of the
target cell of the arrow relatively to the current one.
``vertical_direction`` should specify the vertical offset using a
series of either ``"d"`` or ``"u"``. ``label_position`` should be
either ``"^"``, ``"_"``, or ``"|"`` to specify that the label should
be positioned above the arrow, below the arrow or just over the arrow,
in a break. Note that the notions "above" and "below" are relative
to arrow direction. ``label`` stores the morphism label.
This works as follows (disregard the yet unexplained arguments):
>>> from sympy.categories.diagram_drawing import ArrowStringDescription
>>> astr = ArrowStringDescription(
... unit="mm", curving=None, curving_amount=None,
... looping_start=None, looping_end=None, horizontal_direction="d",
... vertical_direction="r", label_position="_", label="f")
>>> print(str(astr))
\ar[dr]_{f}
``curving`` should be one of ``"^"``, ``"_"`` to specify in which
direction the arrow is going to curve. ``curving_amount`` is a number
describing how many ``unit``'s the morphism is going to curve:
>>> astr = ArrowStringDescription(
... unit="mm", curving="^", curving_amount=12,
... looping_start=None, looping_end=None, horizontal_direction="d",
... vertical_direction="r", label_position="_", label="f")
>>> print(str(astr))
\ar@/^12mm/[dr]_{f}
``looping_start`` and ``looping_end`` are currently only used for
loop morphisms, those which have the same domain and codomain.
These two attributes should store a valid Xy-pic direction and
specify, correspondingly, the direction the arrow gets out into
and the direction the arrow gets back from:
>>> astr = ArrowStringDescription(
... unit="mm", curving=None, curving_amount=None,
... looping_start="u", looping_end="l", horizontal_direction="",
... vertical_direction="", label_position="_", label="f")
>>> print(str(astr))
\ar@(u,l)[]_{f}
``label_displacement`` controls how far the arrow label is from
the ends of the arrow. For example, to position the arrow label
near the arrow head, use ">":
>>> astr = ArrowStringDescription(
... unit="mm", curving="^", curving_amount=12,
... looping_start=None, looping_end=None, horizontal_direction="d",
... vertical_direction="r", label_position="_", label="f")
>>> astr.label_displacement = ">"
>>> print(str(astr))
\ar@/^12mm/[dr]_>{f}
Finally, ``arrow_style`` is used to specify the arrow style. To
get a dashed arrow, for example, use "{-->}" as arrow style:
>>> astr = ArrowStringDescription(
... unit="mm", curving="^", curving_amount=12,
... looping_start=None, looping_end=None, horizontal_direction="d",
... vertical_direction="r", label_position="_", label="f")
>>> astr.arrow_style = "{-->}"
>>> print(str(astr))
\ar@/^12mm/@{-->}[dr]_{f}
Notes
=====
Instances of :class:`ArrowStringDescription` will be constructed
by :class:`XypicDiagramDrawer` and provided for further use in
formatters. The user is not expected to construct instances of
:class:`ArrowStringDescription` themselves.
To be able to properly utilise this class, the reader is encouraged
to checkout the Xy-pic user guide, available at [Xypic].
See Also
========
XypicDiagramDrawer
References
==========
.. [Xypic] https://xy-pic.sourceforge.net/
"""
def __init__(self, unit, curving, curving_amount, looping_start,
looping_end, horizontal_direction, vertical_direction,
label_position, label):
self.unit = unit
self.curving = curving
self.curving_amount = curving_amount
self.looping_start = looping_start
self.looping_end = looping_end
self.horizontal_direction = horizontal_direction
self.vertical_direction = vertical_direction
self.label_position = label_position
self.label = label
self.label_displacement = ""
self.arrow_style = ""
# This flag shows that the position of the label of this
# morphism was set while typesetting a curved morphism and
# should not be modified later.
self.forced_label_position = False
def __str__(self):
if self.curving:
curving_str = "@/%s%d%s/" % (self.curving, self.curving_amount,
self.unit)
else:
curving_str = ""
if self.looping_start and self.looping_end:
looping_str = "@(%s,%s)" % (self.looping_start, self.looping_end)
else:
looping_str = ""
if self.arrow_style:
style_str = "@" + self.arrow_style
else:
style_str = ""
return "\\ar%s%s%s[%s%s]%s%s{%s}" % \
(curving_str, looping_str, style_str, self.horizontal_direction,
self.vertical_direction, self.label_position,
self.label_displacement, self.label)
class XypicDiagramDrawer:
r"""
Given a :class:`~.Diagram` and the corresponding
:class:`DiagramGrid`, produces the Xy-pic representation of the
diagram.
The most important method in this class is ``draw``. Consider the
following triangle diagram:
>>> from sympy.categories import Object, NamedMorphism, Diagram
>>> from sympy.categories import DiagramGrid, XypicDiagramDrawer
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> diagram = Diagram([f, g], {g * f: "unique"})
To draw this diagram, its objects need to be laid out with a
:class:`DiagramGrid`::
>>> grid = DiagramGrid(diagram)
Finally, the drawing:
>>> drawer = XypicDiagramDrawer()
>>> print(drawer.draw(diagram, grid))
\xymatrix{
A \ar[d]_{g\circ f} \ar[r]^{f} & B \ar[ld]^{g} \\
C &
}
For further details see the docstring of this method.
To control the appearance of the arrows, formatters are used. The
dictionary ``arrow_formatters`` maps morphisms to formatter
functions. A formatter is accepts an
:class:`ArrowStringDescription` and is allowed to modify any of
the arrow properties exposed thereby. For example, to have all
morphisms with the property ``unique`` appear as dashed arrows,
and to have their names prepended with `\exists !`, the following
should be done:
>>> def formatter(astr):
... astr.label = r"\exists !" + astr.label
... astr.arrow_style = "{-->}"
>>> drawer.arrow_formatters["unique"] = formatter
>>> print(drawer.draw(diagram, grid))
\xymatrix{
A \ar@{-->}[d]_{\exists !g\circ f} \ar[r]^{f} & B \ar[ld]^{g} \\
C &
}
To modify the appearance of all arrows in the diagram, set
``default_arrow_formatter``. For example, to place all morphism
labels a little bit farther from the arrow head so that they look
more centred, do as follows:
>>> def default_formatter(astr):
... astr.label_displacement = "(0.45)"
>>> drawer.default_arrow_formatter = default_formatter
>>> print(drawer.draw(diagram, grid))
\xymatrix{
A \ar@{-->}[d]_(0.45){\exists !g\circ f} \ar[r]^(0.45){f} & B \ar[ld]^(0.45){g} \\
C &
}
In some diagrams some morphisms are drawn as curved arrows.
Consider the following diagram:
>>> D = Object("D")
>>> E = Object("E")
>>> h = NamedMorphism(D, A, "h")
>>> k = NamedMorphism(D, B, "k")
>>> diagram = Diagram([f, g, h, k])
>>> grid = DiagramGrid(diagram)
>>> drawer = XypicDiagramDrawer()
>>> print(drawer.draw(diagram, grid))
\xymatrix{
A \ar[r]_{f} & B \ar[d]^{g} & D \ar[l]^{k} \ar@/_3mm/[ll]_{h} \\
& C &
}
To control how far the morphisms are curved by default, one can
use the ``unit`` and ``default_curving_amount`` attributes:
>>> drawer.unit = "cm"
>>> drawer.default_curving_amount = 1
>>> print(drawer.draw(diagram, grid))
\xymatrix{
A \ar[r]_{f} & B \ar[d]^{g} & D \ar[l]^{k} \ar@/_1cm/[ll]_{h} \\
& C &
}
In some diagrams, there are multiple curved morphisms between the
same two objects. To control by how much the curving changes
between two such successive morphisms, use
``default_curving_step``:
>>> drawer.default_curving_step = 1
>>> h1 = NamedMorphism(A, D, "h1")
>>> diagram = Diagram([f, g, h, k, h1])
>>> grid = DiagramGrid(diagram)
>>> print(drawer.draw(diagram, grid))
\xymatrix{
A \ar[r]_{f} \ar@/^1cm/[rr]^{h_{1}} & B \ar[d]^{g} & D \ar[l]^{k} \ar@/_2cm/[ll]_{h} \\
& C &
}
The default value of ``default_curving_step`` is 4 units.
See Also
========
draw, ArrowStringDescription
"""
def __init__(self):
self.unit = "mm"
self.default_curving_amount = 3
self.default_curving_step = 4
# This dictionary maps properties to the corresponding arrow
# formatters.
self.arrow_formatters = {}
# This is the default arrow formatter which will be applied to
# each arrow independently of its properties.
self.default_arrow_formatter = None
@staticmethod
def _process_loop_morphism(i, j, grid, morphisms_str_info, object_coords):
"""
Produces the information required for constructing the string
representation of a loop morphism. This function is invoked
from ``_process_morphism``.
See Also
========
_process_morphism
"""
curving = ""
label_pos = "^"
looping_start = ""
looping_end = ""
# This is a loop morphism. Count how many morphisms stick
# in each of the four quadrants. Note that straight
# vertical and horizontal morphisms count in two quadrants
# at the same time (i.e., a morphism going up counts both
# in the first and the second quadrants).
# The usual numbering (counterclockwise) of quadrants
# applies.
quadrant = [0, 0, 0, 0]
obj = grid[i, j]
for m, m_str_info in morphisms_str_info.items():
if (m.domain == obj) and (m.codomain == obj):
# That's another loop morphism. Check how it
# loops and mark the corresponding quadrants as
# busy.
(l_s, l_e) = (m_str_info.looping_start, m_str_info.looping_end)
if (l_s, l_e) == ("r", "u"):
quadrant[0] += 1
elif (l_s, l_e) == ("u", "l"):
quadrant[1] += 1
elif (l_s, l_e) == ("l", "d"):
quadrant[2] += 1
elif (l_s, l_e) == ("d", "r"):
quadrant[3] += 1
continue
if m.domain == obj:
(end_i, end_j) = object_coords[m.codomain]
goes_out = True
elif m.codomain == obj:
(end_i, end_j) = object_coords[m.domain]
goes_out = False
else:
continue
d_i = end_i - i
d_j = end_j - j
m_curving = m_str_info.curving
if (d_i != 0) and (d_j != 0):
# This is really a diagonal morphism. Detect the
# quadrant.
if (d_i > 0) and (d_j > 0):
quadrant[0] += 1
elif (d_i > 0) and (d_j < 0):
quadrant[1] += 1
elif (d_i < 0) and (d_j < 0):
quadrant[2] += 1
elif (d_i < 0) and (d_j > 0):
quadrant[3] += 1
elif d_i == 0:
# Knowing where the other end of the morphism is
# and which way it goes, we now have to decide
# which quadrant is now the upper one and which is
# the lower one.
if d_j > 0:
if goes_out:
upper_quadrant = 0
lower_quadrant = 3
else:
upper_quadrant = 3
lower_quadrant = 0
else:
if goes_out:
upper_quadrant = 2
lower_quadrant = 1
else:
upper_quadrant = 1
lower_quadrant = 2
if m_curving:
if m_curving == "^":
quadrant[upper_quadrant] += 1
elif m_curving == "_":
quadrant[lower_quadrant] += 1
else:
# This morphism counts in both upper and lower
# quadrants.
quadrant[upper_quadrant] += 1
quadrant[lower_quadrant] += 1
elif d_j == 0:
# Knowing where the other end of the morphism is
# and which way it goes, we now have to decide
# which quadrant is now the left one and which is
# the right one.
if d_i < 0:
if goes_out:
left_quadrant = 1
right_quadrant = 0
else:
left_quadrant = 0
right_quadrant = 1
else:
if goes_out:
left_quadrant = 3
right_quadrant = 2
else:
left_quadrant = 2
right_quadrant = 3
if m_curving:
if m_curving == "^":
quadrant[left_quadrant] += 1
elif m_curving == "_":
quadrant[right_quadrant] += 1
else:
# This morphism counts in both upper and lower
# quadrants.
quadrant[left_quadrant] += 1
quadrant[right_quadrant] += 1
# Pick the freest quadrant to curve our morphism into.
freest_quadrant = 0
for i in range(4):
if quadrant[i] < quadrant[freest_quadrant]:
freest_quadrant = i
# Now set up proper looping.
(looping_start, looping_end) = [("r", "u"), ("u", "l"), ("l", "d"),
("d", "r")][freest_quadrant]
return (curving, label_pos, looping_start, looping_end)
@staticmethod
def _process_horizontal_morphism(i, j, target_j, grid, morphisms_str_info,
object_coords):
"""
Produces the information required for constructing the string
representation of a horizontal morphism. This function is
invoked from ``_process_morphism``.
See Also
========
_process_morphism
"""
# The arrow is horizontal. Check if it goes from left to
# right (``backwards == False``) or from right to left
# (``backwards == True``).
backwards = False
start = j
end = target_j
if end < start:
(start, end) = (end, start)
backwards = True
# Let's see which objects are there between ``start`` and
# ``end``, and then count how many morphisms stick out
# upwards, and how many stick out downwards.
#
# For example, consider the situation:
#
# B1 C1
# | |
# A--B--C--D
# |
# B2
#
# Between the objects `A` and `D` there are two objects:
# `B` and `C`. Further, there are two morphisms which
# stick out upward (the ones between `B1` and `B` and
# between `C` and `C1`) and one morphism which sticks out
# downward (the one between `B and `B2`).
#
# We need this information to decide how to curve the
# arrow between `A` and `D`. First of all, since there
# are two objects between `A` and `D``, we must curve the
# arrow. Then, we will have it curve downward, because
# there is more space (less morphisms stick out downward
# than upward).
up = []
down = []
straight_horizontal = []
for k in range(start + 1, end):
obj = grid[i, k]
if not obj:
continue
for m in morphisms_str_info:
if m.domain == obj:
(end_i, end_j) = object_coords[m.codomain]
elif m.codomain == obj:
(end_i, end_j) = object_coords[m.domain]
else:
continue
if end_i > i:
down.append(m)
elif end_i < i:
up.append(m)
elif not morphisms_str_info[m].curving:
# This is a straight horizontal morphism,
# because it has no curving.
straight_horizontal.append(m)
if len(up) < len(down):
# More morphisms stick out downward than upward, let's
# curve the morphism up.
if backwards:
curving = "_"
label_pos = "_"
else:
curving = "^"
label_pos = "^"
# Assure that the straight horizontal morphisms have
# their labels on the lower side of the arrow.
for m in straight_horizontal:
(i1, j1) = object_coords[m.domain]
(i2, j2) = object_coords[m.codomain]
m_str_info = morphisms_str_info[m]
if j1 < j2:
m_str_info.label_position = "_"
else:
m_str_info.label_position = "^"
# Don't allow any further modifications of the
# position of this label.
m_str_info.forced_label_position = True
else:
# More morphisms stick out downward than upward, let's
# curve the morphism up.
if backwards:
curving = "^"
label_pos = "^"
else:
curving = "_"
label_pos = "_"
# Assure that the straight horizontal morphisms have
# their labels on the upper side of the arrow.
for m in straight_horizontal:
(i1, j1) = object_coords[m.domain]
(i2, j2) = object_coords[m.codomain]
m_str_info = morphisms_str_info[m]
if j1 < j2:
m_str_info.label_position = "^"
else:
m_str_info.label_position = "_"
# Don't allow any further modifications of the
# position of this label.
m_str_info.forced_label_position = True
return (curving, label_pos)
@staticmethod
def _process_vertical_morphism(i, j, target_i, grid, morphisms_str_info,
object_coords):
"""
Produces the information required for constructing the string
representation of a vertical morphism. This function is
invoked from ``_process_morphism``.
See Also
========
_process_morphism
"""
# This arrow is vertical. Check if it goes from top to
# bottom (``backwards == False``) or from bottom to top
# (``backwards == True``).
backwards = False
start = i
end = target_i
if end < start:
(start, end) = (end, start)
backwards = True
# Let's see which objects are there between ``start`` and
# ``end``, and then count how many morphisms stick out to
# the left, and how many stick out to the right.
#
# See the corresponding comment in the previous branch of
# this if-statement for more details.
left = []
right = []
straight_vertical = []
for k in range(start + 1, end):
obj = grid[k, j]
if not obj:
continue
for m in morphisms_str_info:
if m.domain == obj:
(end_i, end_j) = object_coords[m.codomain]
elif m.codomain == obj:
(end_i, end_j) = object_coords[m.domain]
else:
continue
if end_j > j:
right.append(m)
elif end_j < j:
left.append(m)
elif not morphisms_str_info[m].curving:
# This is a straight vertical morphism,
# because it has no curving.
straight_vertical.append(m)
if len(left) < len(right):
# More morphisms stick out to the left than to the
# right, let's curve the morphism to the right.
if backwards:
curving = "^"
label_pos = "^"
else:
curving = "_"
label_pos = "_"
# Assure that the straight vertical morphisms have
# their labels on the left side of the arrow.
for m in straight_vertical:
(i1, j1) = object_coords[m.domain]
(i2, j2) = object_coords[m.codomain]
m_str_info = morphisms_str_info[m]
if i1 < i2:
m_str_info.label_position = "^"
else:
m_str_info.label_position = "_"
# Don't allow any further modifications of the
# position of this label.
m_str_info.forced_label_position = True
else:
# More morphisms stick out to the right than to the
# left, let's curve the morphism to the left.
if backwards:
curving = "_"
label_pos = "_"
else:
curving = "^"
label_pos = "^"
# Assure that the straight vertical morphisms have
# their labels on the right side of the arrow.
for m in straight_vertical:
(i1, j1) = object_coords[m.domain]
(i2, j2) = object_coords[m.codomain]
m_str_info = morphisms_str_info[m]
if i1 < i2:
m_str_info.label_position = "_"
else:
m_str_info.label_position = "^"
# Don't allow any further modifications of the
# position of this label.
m_str_info.forced_label_position = True
return (curving, label_pos)
def _process_morphism(self, diagram, grid, morphism, object_coords,
morphisms, morphisms_str_info):
"""
Given the required information, produces the string
representation of ``morphism``.
"""
def repeat_string_cond(times, str_gt, str_lt):
"""
If ``times > 0``, repeats ``str_gt`` ``times`` times.
Otherwise, repeats ``str_lt`` ``-times`` times.
"""
if times > 0:
return str_gt * times
else:
return str_lt * (-times)
def count_morphisms_undirected(A, B):
"""
Counts how many processed morphisms there are between the
two supplied objects.
"""
return len([m for m in morphisms_str_info
if {m.domain, m.codomain} == {A, B}])
def count_morphisms_filtered(dom, cod, curving):
"""
Counts the processed morphisms which go out of ``dom``
into ``cod`` with curving ``curving``.
"""
return len([m for m, m_str_info in morphisms_str_info.items()
if (m.domain, m.codomain) == (dom, cod) and
(m_str_info.curving == curving)])
(i, j) = object_coords[morphism.domain]
(target_i, target_j) = object_coords[morphism.codomain]
# We now need to determine the direction of
# the arrow.
delta_i = target_i - i
delta_j = target_j - j
vertical_direction = repeat_string_cond(delta_i,
"d", "u")
horizontal_direction = repeat_string_cond(delta_j,
"r", "l")
curving = ""
label_pos = "^"
looping_start = ""
looping_end = ""
if (delta_i == 0) and (delta_j == 0):
# This is a loop morphism.
(curving, label_pos, looping_start,
looping_end) = XypicDiagramDrawer._process_loop_morphism(
i, j, grid, morphisms_str_info, object_coords)
elif (delta_i == 0) and (abs(j - target_j) > 1):
# This is a horizontal morphism.
(curving, label_pos) = XypicDiagramDrawer._process_horizontal_morphism(
i, j, target_j, grid, morphisms_str_info, object_coords)
elif (delta_j == 0) and (abs(i - target_i) > 1):
# This is a vertical morphism.
(curving, label_pos) = XypicDiagramDrawer._process_vertical_morphism(
i, j, target_i, grid, morphisms_str_info, object_coords)
count = count_morphisms_undirected(morphism.domain, morphism.codomain)
curving_amount = ""
if curving:
# This morphisms should be curved anyway.
curving_amount = self.default_curving_amount + count * \
self.default_curving_step
elif count:
# There are no objects between the domain and codomain of
# the current morphism, but this is not there already are
# some morphisms with the same domain and codomain, so we
# have to curve this one.
curving = "^"
filtered_morphisms = count_morphisms_filtered(
morphism.domain, morphism.codomain, curving)
curving_amount = self.default_curving_amount + \
filtered_morphisms * \
self.default_curving_step
# Let's now get the name of the morphism.
morphism_name = ""
if isinstance(morphism, IdentityMorphism):
morphism_name = "id_{%s}" + latex(grid[i, j])
elif isinstance(morphism, CompositeMorphism):
component_names = [latex(Symbol(component.name)) for
component in morphism.components]
component_names.reverse()
morphism_name = "\\circ ".join(component_names)
elif isinstance(morphism, NamedMorphism):
morphism_name = latex(Symbol(morphism.name))
return ArrowStringDescription(
self.unit, curving, curving_amount, looping_start,
looping_end, horizontal_direction, vertical_direction,
label_pos, morphism_name)
@staticmethod
def _check_free_space_horizontal(dom_i, dom_j, cod_j, grid):
"""
For a horizontal morphism, checks whether there is free space
(i.e., space not occupied by any objects) above the morphism
or below it.
"""
if dom_j < cod_j:
(start, end) = (dom_j, cod_j)
backwards = False
else:
(start, end) = (cod_j, dom_j)
backwards = True
# Check for free space above.
if dom_i == 0:
free_up = True
else:
free_up = all(grid[dom_i - 1, j] for j in
range(start, end + 1))
# Check for free space below.
if dom_i == grid.height - 1:
free_down = True
else:
free_down = not any(grid[dom_i + 1, j] for j in
range(start, end + 1))
return (free_up, free_down, backwards)
@staticmethod
def _check_free_space_vertical(dom_i, cod_i, dom_j, grid):
"""
For a vertical morphism, checks whether there is free space
(i.e., space not occupied by any objects) to the left of the
morphism or to the right of it.
"""
if dom_i < cod_i:
(start, end) = (dom_i, cod_i)
backwards = False
else:
(start, end) = (cod_i, dom_i)
backwards = True
# Check if there's space to the left.
if dom_j == 0:
free_left = True
else:
free_left = not any(grid[i, dom_j - 1] for i in
range(start, end + 1))
if dom_j == grid.width - 1:
free_right = True
else:
free_right = not any(grid[i, dom_j + 1] for i in
range(start, end + 1))
return (free_left, free_right, backwards)
@staticmethod
def _check_free_space_diagonal(dom_i, cod_i, dom_j, cod_j, grid):
"""
For a diagonal morphism, checks whether there is free space
(i.e., space not occupied by any objects) above the morphism
or below it.
"""
def abs_xrange(start, end):
if start < end:
return range(start, end + 1)
else:
return range(end, start + 1)
if dom_i < cod_i and dom_j < cod_j:
# This morphism goes from top-left to
# bottom-right.
(start_i, start_j) = (dom_i, dom_j)
(end_i, end_j) = (cod_i, cod_j)
backwards = False
elif dom_i > cod_i and dom_j > cod_j:
# This morphism goes from bottom-right to
# top-left.
(start_i, start_j) = (cod_i, cod_j)
(end_i, end_j) = (dom_i, dom_j)
backwards = True
if dom_i < cod_i and dom_j > cod_j:
# This morphism goes from top-right to
# bottom-left.
(start_i, start_j) = (dom_i, dom_j)
(end_i, end_j) = (cod_i, cod_j)
backwards = True
elif dom_i > cod_i and dom_j < cod_j:
# This morphism goes from bottom-left to
# top-right.
(start_i, start_j) = (cod_i, cod_j)
(end_i, end_j) = (dom_i, dom_j)
backwards = False
# This is an attempt at a fast and furious strategy to
# decide where there is free space on the two sides of
# a diagonal morphism. For a diagonal morphism
# starting at ``(start_i, start_j)`` and ending at
# ``(end_i, end_j)`` the rectangle defined by these
# two points is considered. The slope of the diagonal
# ``alpha`` is then computed. Then, for every cell
# ``(i, j)`` within the rectangle, the slope
# ``alpha1`` of the line through ``(start_i,
# start_j)`` and ``(i, j)`` is considered. If
# ``alpha1`` is between 0 and ``alpha``, the point
# ``(i, j)`` is above the diagonal, if ``alpha1`` is
# between ``alpha`` and infinity, the point is below
# the diagonal. Also note that, with some beforehand
# precautions, this trick works for both the main and
# the secondary diagonals of the rectangle.
# I have considered the possibility to only follow the
# shorter diagonals immediately above and below the
# main (or secondary) diagonal. This, however,
# wouldn't have resulted in much performance gain or
# better detection of outer edges, because of
# relatively small sizes of diagram grids, while the
# code would have become harder to understand.
alpha = float(end_i - start_i)/(end_j - start_j)
free_up = True
free_down = True
for i in abs_xrange(start_i, end_i):
if not free_up and not free_down:
break
for j in abs_xrange(start_j, end_j):
if not free_up and not free_down:
break
if (i, j) == (start_i, start_j):
continue
if j == start_j:
alpha1 = "inf"
else:
alpha1 = float(i - start_i)/(j - start_j)
if grid[i, j]:
if (alpha1 == "inf") or (abs(alpha1) > abs(alpha)):
free_down = False
elif abs(alpha1) < abs(alpha):
free_up = False
return (free_up, free_down, backwards)
def _push_labels_out(self, morphisms_str_info, grid, object_coords):
"""
For all straight morphisms which form the visual boundary of
the laid out diagram, puts their labels on their outer sides.
"""
def set_label_position(free1, free2, pos1, pos2, backwards, m_str_info):
"""
Given the information about room available to one side and
to the other side of a morphism (``free1`` and ``free2``),
sets the position of the morphism label in such a way that
it is on the freer side. This latter operations involves
choice between ``pos1`` and ``pos2``, taking ``backwards``
in consideration.
Thus this function will do nothing if either both ``free1
== True`` and ``free2 == True`` or both ``free1 == False``
and ``free2 == False``. In either case, choosing one side
over the other presents no advantage.
"""
if backwards:
(pos1, pos2) = (pos2, pos1)
if free1 and not free2:
m_str_info.label_position = pos1
elif free2 and not free1:
m_str_info.label_position = pos2
for m, m_str_info in morphisms_str_info.items():
if m_str_info.curving or m_str_info.forced_label_position:
# This is either a curved morphism, and curved
# morphisms have other magic, or the position of this
# label has already been fixed.
continue
if m.domain == m.codomain:
# This is a loop morphism, their labels, again have a
# different magic.
continue
(dom_i, dom_j) = object_coords[m.domain]
(cod_i, cod_j) = object_coords[m.codomain]
if dom_i == cod_i:
# Horizontal morphism.
(free_up, free_down,
backwards) = XypicDiagramDrawer._check_free_space_horizontal(
dom_i, dom_j, cod_j, grid)
set_label_position(free_up, free_down, "^", "_",
backwards, m_str_info)
elif dom_j == cod_j:
# Vertical morphism.
(free_left, free_right,
backwards) = XypicDiagramDrawer._check_free_space_vertical(
dom_i, cod_i, dom_j, grid)
set_label_position(free_left, free_right, "_", "^",
backwards, m_str_info)
else:
# A diagonal morphism.
(free_up, free_down,
backwards) = XypicDiagramDrawer._check_free_space_diagonal(
dom_i, cod_i, dom_j, cod_j, grid)
set_label_position(free_up, free_down, "^", "_",
backwards, m_str_info)
@staticmethod
def _morphism_sort_key(morphism, object_coords):
"""
Provides a morphism sorting key such that horizontal or
vertical morphisms between neighbouring objects come
first, then horizontal or vertical morphisms between more
far away objects, and finally, all other morphisms.
"""
(i, j) = object_coords[morphism.domain]
(target_i, target_j) = object_coords[morphism.codomain]
if morphism.domain == morphism.codomain:
# Loop morphisms should get after diagonal morphisms
# so that the proper direction in which to curve the
# loop can be determined.
return (3, 0, default_sort_key(morphism))
if target_i == i:
return (1, abs(target_j - j), default_sort_key(morphism))
if target_j == j:
return (1, abs(target_i - i), default_sort_key(morphism))
# Diagonal morphism.
return (2, 0, default_sort_key(morphism))
@staticmethod
def _build_xypic_string(diagram, grid, morphisms,
morphisms_str_info, diagram_format):
"""
Given a collection of :class:`ArrowStringDescription`
describing the morphisms of a diagram and the object layout
information of a diagram, produces the final Xy-pic picture.
"""
# Build the mapping between objects and morphisms which have
# them as domains.
object_morphisms = {}
for obj in diagram.objects:
object_morphisms[obj] = []
for morphism in morphisms:
object_morphisms[morphism.domain].append(morphism)
result = "\\xymatrix%s{\n" % diagram_format
for i in range(grid.height):
for j in range(grid.width):
obj = grid[i, j]
if obj:
result += latex(obj) + " "
morphisms_to_draw = object_morphisms[obj]
for morphism in morphisms_to_draw:
result += str(morphisms_str_info[morphism]) + " "
# Don't put the & after the last column.
if j < grid.width - 1:
result += "& "
# Don't put the line break after the last row.
if i < grid.height - 1:
result += "\\\\"
result += "\n"
result += "}\n"
return result
def draw(self, diagram, grid, masked=None, diagram_format=""):
r"""
Returns the Xy-pic representation of ``diagram`` laid out in
``grid``.
Consider the following simple triangle diagram.
>>> from sympy.categories import Object, NamedMorphism, Diagram
>>> from sympy.categories import DiagramGrid, XypicDiagramDrawer
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> diagram = Diagram([f, g], {g * f: "unique"})
To draw this diagram, its objects need to be laid out with a
:class:`DiagramGrid`::
>>> grid = DiagramGrid(diagram)
Finally, the drawing:
>>> drawer = XypicDiagramDrawer()
>>> print(drawer.draw(diagram, grid))
\xymatrix{
A \ar[d]_{g\circ f} \ar[r]^{f} & B \ar[ld]^{g} \\
C &
}
The argument ``masked`` can be used to skip morphisms in the
presentation of the diagram:
>>> print(drawer.draw(diagram, grid, masked=[g * f]))
\xymatrix{
A \ar[r]^{f} & B \ar[ld]^{g} \\
C &
}
Finally, the ``diagram_format`` argument can be used to
specify the format string of the diagram. For example, to
increase the spacing by 1 cm, proceeding as follows:
>>> print(drawer.draw(diagram, grid, diagram_format="@+1cm"))
\xymatrix@+1cm{
A \ar[d]_{g\circ f} \ar[r]^{f} & B \ar[ld]^{g} \\
C &
}
"""
# This method works in several steps. It starts by removing
# the masked morphisms, if necessary, and then maps objects to
# their positions in the grid (coordinate tuples). Remember
# that objects are unique in ``Diagram`` and in the layout
# produced by ``DiagramGrid``, so every object is mapped to a
# single coordinate pair.
#
# The next step is the central step and is concerned with
# analysing the morphisms of the diagram and deciding how to
# draw them. For example, how to curve the arrows is decided
# at this step. The bulk of the analysis is implemented in
# ``_process_morphism``, to the result of which the
# appropriate formatters are applied.
#
# The result of the previous step is a list of
# ``ArrowStringDescription``. After the analysis and
# application of formatters, some extra logic tries to assure
# better positioning of morphism labels (for example, an
# attempt is made to avoid the situations when arrows cross
# labels). This functionality constitutes the next step and
# is implemented in ``_push_labels_out``. Note that label
# positions which have been set via a formatter are not
# affected in this step.
#
# Finally, at the closing step, the array of
# ``ArrowStringDescription`` and the layout information
# incorporated in ``DiagramGrid`` are combined to produce the
# resulting Xy-pic picture. This part of code lies in
# ``_build_xypic_string``.
if not masked:
morphisms_props = grid.morphisms
else:
morphisms_props = {}
for m, props in grid.morphisms.items():
if m in masked:
continue
morphisms_props[m] = props
# Build the mapping between objects and their position in the
# grid.
object_coords = {}
for i in range(grid.height):
for j in range(grid.width):
if grid[i, j]:
object_coords[grid[i, j]] = (i, j)
morphisms = sorted(morphisms_props,
key=lambda m: XypicDiagramDrawer._morphism_sort_key(
m, object_coords))
# Build the tuples defining the string representations of
# morphisms.
morphisms_str_info = {}
for morphism in morphisms:
string_description = self._process_morphism(
diagram, grid, morphism, object_coords, morphisms,
morphisms_str_info)
if self.default_arrow_formatter:
self.default_arrow_formatter(string_description)
for prop in morphisms_props[morphism]:
# prop is a Symbol. TODO: Find out why.
if prop.name in self.arrow_formatters:
formatter = self.arrow_formatters[prop.name]
formatter(string_description)
morphisms_str_info[morphism] = string_description
# Reposition the labels a bit.
self._push_labels_out(morphisms_str_info, grid, object_coords)
return XypicDiagramDrawer._build_xypic_string(
diagram, grid, morphisms, morphisms_str_info, diagram_format)
def xypic_draw_diagram(diagram, masked=None, diagram_format="",
groups=None, **hints):
r"""
Provides a shortcut combining :class:`DiagramGrid` and
:class:`XypicDiagramDrawer`. Returns an Xy-pic presentation of
``diagram``. The argument ``masked`` is a list of morphisms which
will be not be drawn. The argument ``diagram_format`` is the
format string inserted after "\xymatrix". ``groups`` should be a
set of logical groups. The ``hints`` will be passed directly to
the constructor of :class:`DiagramGrid`.
For more information about the arguments, see the docstrings of
:class:`DiagramGrid` and ``XypicDiagramDrawer.draw``.
Examples
========
>>> from sympy.categories import Object, NamedMorphism, Diagram
>>> from sympy.categories import xypic_draw_diagram
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> diagram = Diagram([f, g], {g * f: "unique"})
>>> print(xypic_draw_diagram(diagram))
\xymatrix{
A \ar[d]_{g\circ f} \ar[r]^{f} & B \ar[ld]^{g} \\
C &
}
See Also
========
XypicDiagramDrawer, DiagramGrid
"""
grid = DiagramGrid(diagram, groups, **hints)
drawer = XypicDiagramDrawer()
return drawer.draw(diagram, grid, masked, diagram_format)
@doctest_depends_on(exe=('latex', 'dvipng'), modules=('pyglet',))
def preview_diagram(diagram, masked=None, diagram_format="", groups=None,
output='png', viewer=None, euler=True, **hints):
"""
Combines the functionality of ``xypic_draw_diagram`` and
``sympy.printing.preview``. The arguments ``masked``,
``diagram_format``, ``groups``, and ``hints`` are passed to
``xypic_draw_diagram``, while ``output``, ``viewer, and ``euler``
are passed to ``preview``.
Examples
========
>>> from sympy.categories import Object, NamedMorphism, Diagram
>>> from sympy.categories import preview_diagram
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> d = Diagram([f, g], {g * f: "unique"})
>>> preview_diagram(d)
See Also
========
XypicDiagramDrawer
"""
from sympy.printing import preview
latex_output = xypic_draw_diagram(diagram, masked, diagram_format,
groups, **hints)
preview(latex_output, output, viewer, euler, ("xypic",))
PK ]ZZZ�X�� � sympy/codegen/__init__.py""" The ``sympy.codegen`` module contains classes and functions for building
abstract syntax trees of algorithms. These trees may then be printed by the
code-printers in ``sympy.printing``.
There are several submodules available:
- ``sympy.codegen.ast``: AST nodes useful across multiple languages.
- ``sympy.codegen.cnodes``: AST nodes useful for the C family of languages.
- ``sympy.codegen.fnodes``: AST nodes useful for Fortran.
- ``sympy.codegen.cfunctions``: functions specific to C (C99 math functions)
- ``sympy.codegen.ffunctions``: functions specific to Fortran (e.g. ``kind``).
"""
from .ast import (
Assignment, aug_assign, CodeBlock, For, Attribute, Variable, Declaration,
While, Scope, Print, FunctionPrototype, FunctionDefinition, FunctionCall
)
__all__ = [
'Assignment', 'aug_assign', 'CodeBlock', 'For', 'Attribute', 'Variable',
'Declaration', 'While', 'Scope', 'Print', 'FunctionPrototype',
'FunctionDefinition', 'FunctionCall',
]
PK ]ZZZ٠J�� � sympy/codegen/abstract_nodes.py"""This module provides containers for python objects that are valid
printing targets but are not a subclass of SymPy's Printable.
"""
from sympy.core.containers import Tuple
class List(Tuple):
"""Represents a (frozen) (Python) list (for code printing purposes)."""
def __eq__(self, other):
if isinstance(other, list):
return self == List(*other)
else:
return self.args == other
def __hash__(self):
return super().__hash__()
PK ]ZZZ��]p� � sympy/codegen/algorithms.pyfrom sympy.core.containers import Tuple
from sympy.core.numbers import oo
from sympy.core.relational import (Gt, Lt)
from sympy.core.symbol import (Dummy, Symbol)
from sympy.functions.elementary.complexes import Abs
from sympy.functions.elementary.miscellaneous import Min, Max
from sympy.logic.boolalg import And
from sympy.codegen.ast import (
Assignment, AddAugmentedAssignment, break_, CodeBlock, Declaration, FunctionDefinition,
Print, Return, Scope, While, Variable, Pointer, real
)
from sympy.codegen.cfunctions import isnan
""" This module collects functions for constructing ASTs representing algorithms. """
def newtons_method(expr, wrt, atol=1e-12, delta=None, *, rtol=4e-16, debug=False,
itermax=None, counter=None, delta_fn=lambda e, x: -e/e.diff(x),
cse=False, handle_nan=None,
bounds=None):
""" Generates an AST for Newton-Raphson method (a root-finding algorithm).
Explanation
===========
Returns an abstract syntax tree (AST) based on ``sympy.codegen.ast`` for Netwon's
method of root-finding.
Parameters
==========
expr : expression
wrt : Symbol
With respect to, i.e. what is the variable.
atol : number or expression
Absolute tolerance (stopping criterion)
rtol : number or expression
Relative tolerance (stopping criterion)
delta : Symbol
Will be a ``Dummy`` if ``None``.
debug : bool
Whether to print convergence information during iterations
itermax : number or expr
Maximum number of iterations.
counter : Symbol
Will be a ``Dummy`` if ``None``.
delta_fn: Callable[[Expr, Symbol], Expr]
computes the step, default is newtons method. For e.g. Halley's method
use delta_fn=lambda e, x: -2*e*e.diff(x)/(2*e.diff(x)**2 - e*e.diff(x, 2))
cse: bool
Perform common sub-expression elimination on delta expression
handle_nan: Token
How to handle occurrence of not-a-number (NaN).
bounds: Optional[tuple[Expr, Expr]]
Perform optimization within bounds
Examples
========
>>> from sympy import symbols, cos
>>> from sympy.codegen.ast import Assignment
>>> from sympy.codegen.algorithms import newtons_method
>>> x, dx, atol = symbols('x dx atol')
>>> expr = cos(x) - x**3
>>> algo = newtons_method(expr, x, atol=atol, delta=dx)
>>> algo.has(Assignment(dx, -expr/expr.diff(x)))
True
References
==========
.. [1] https://en.wikipedia.org/wiki/Newton%27s_method
"""
if delta is None:
delta = Dummy()
Wrapper = Scope
name_d = 'delta'
else:
Wrapper = lambda x: x
name_d = delta.name
delta_expr = delta_fn(expr, wrt)
if cse:
from sympy.simplify.cse_main import cse
cses, (red,) = cse([delta_expr.factor()])
whl_bdy = [Assignment(dum, sub_e) for dum, sub_e in cses]
whl_bdy += [Assignment(delta, red)]
else:
whl_bdy = [Assignment(delta, delta_expr)]
if handle_nan is not None:
whl_bdy += [While(isnan(delta), CodeBlock(handle_nan, break_))]
whl_bdy += [AddAugmentedAssignment(wrt, delta)]
if bounds is not None:
whl_bdy += [Assignment(wrt, Min(Max(wrt, bounds[0]), bounds[1]))]
if debug:
prnt = Print([wrt, delta], r"{}=%12.5g {}=%12.5g\n".format(wrt.name, name_d))
whl_bdy += [prnt]
req = Gt(Abs(delta), atol + rtol*Abs(wrt))
declars = [Declaration(Variable(delta, type=real, value=oo))]
if itermax is not None:
counter = counter or Dummy(integer=True)
v_counter = Variable.deduced(counter, 0)
declars.append(Declaration(v_counter))
whl_bdy.append(AddAugmentedAssignment(counter, 1))
req = And(req, Lt(counter, itermax))
whl = While(req, CodeBlock(*whl_bdy))
blck = declars
if debug:
blck.append(Print([wrt], r"{}=%12.5g\n".format(wrt.name)))
blck += [whl]
return Wrapper(CodeBlock(*blck))
def _symbol_of(arg):
if isinstance(arg, Declaration):
arg = arg.variable.symbol
elif isinstance(arg, Variable):
arg = arg.symbol
return arg
def newtons_method_function(expr, wrt, params=None, func_name="newton", attrs=Tuple(), *, delta=None, **kwargs):
""" Generates an AST for a function implementing the Newton-Raphson method.
Parameters
==========
expr : expression
wrt : Symbol
With respect to, i.e. what is the variable
params : iterable of symbols
Symbols appearing in expr that are taken as constants during the iterations
(these will be accepted as parameters to the generated function).
func_name : str
Name of the generated function.
attrs : Tuple
Attribute instances passed as ``attrs`` to ``FunctionDefinition``.
\\*\\*kwargs :
Keyword arguments passed to :func:`sympy.codegen.algorithms.newtons_method`.
Examples
========
>>> from sympy import symbols, cos
>>> from sympy.codegen.algorithms import newtons_method_function
>>> from sympy.codegen.pyutils import render_as_module
>>> x = symbols('x')
>>> expr = cos(x) - x**3
>>> func = newtons_method_function(expr, x)
>>> py_mod = render_as_module(func) # source code as string
>>> namespace = {}
>>> exec(py_mod, namespace, namespace)
>>> res = eval('newton(0.5)', namespace)
>>> abs(res - 0.865474033102) < 1e-12
True
See Also
========
sympy.codegen.algorithms.newtons_method
"""
if params is None:
params = (wrt,)
pointer_subs = {p.symbol: Symbol('(*%s)' % p.symbol.name)
for p in params if isinstance(p, Pointer)}
if delta is None:
delta = Symbol('d_' + wrt.name)
if expr.has(delta):
delta = None # will use Dummy
algo = newtons_method(expr, wrt, delta=delta, **kwargs).xreplace(pointer_subs)
if isinstance(algo, Scope):
algo = algo.body
not_in_params = expr.free_symbols.difference({_symbol_of(p) for p in params})
if not_in_params:
raise ValueError("Missing symbols in params: %s" % ', '.join(map(str, not_in_params)))
declars = tuple(Variable(p, real) for p in params)
body = CodeBlock(algo, Return(wrt))
return FunctionDefinition(real, func_name, declars, body, attrs=attrs)
PK ]ZZZf0g5/ / sympy/codegen/approximations.pyimport math
from sympy.sets.sets import Interval
from sympy.calculus.singularities import is_increasing, is_decreasing
from sympy.codegen.rewriting import Optimization
from sympy.core.function import UndefinedFunction
"""
This module collects classes useful for approimate rewriting of expressions.
This can be beneficial when generating numeric code for which performance is
of greater importance than precision (e.g. for preconditioners used in iterative
methods).
"""
class SumApprox(Optimization):
"""
Approximates sum by neglecting small terms.
Explanation
===========
If terms are expressions which can be determined to be monotonic, then
bounds for those expressions are added.
Parameters
==========
bounds : dict
Mapping expressions to length 2 tuple of bounds (low, high).
reltol : number
Threshold for when to ignore a term. Taken relative to the largest
lower bound among bounds.
Examples
========
>>> from sympy import exp
>>> from sympy.abc import x, y, z
>>> from sympy.codegen.rewriting import optimize
>>> from sympy.codegen.approximations import SumApprox
>>> bounds = {x: (-1, 1), y: (1000, 2000), z: (-10, 3)}
>>> sum_approx3 = SumApprox(bounds, reltol=1e-3)
>>> sum_approx2 = SumApprox(bounds, reltol=1e-2)
>>> sum_approx1 = SumApprox(bounds, reltol=1e-1)
>>> expr = 3*(x + y + exp(z))
>>> optimize(expr, [sum_approx3])
3*(x + y + exp(z))
>>> optimize(expr, [sum_approx2])
3*y + 3*exp(z)
>>> optimize(expr, [sum_approx1])
3*y
"""
def __init__(self, bounds, reltol, **kwargs):
super().__init__(**kwargs)
self.bounds = bounds
self.reltol = reltol
def __call__(self, expr):
return expr.factor().replace(self.query, lambda arg: self.value(arg))
def query(self, expr):
return expr.is_Add
def value(self, add):
for term in add.args:
if term.is_number or term in self.bounds or len(term.free_symbols) != 1:
continue
fs, = term.free_symbols
if fs not in self.bounds:
continue
intrvl = Interval(*self.bounds[fs])
if is_increasing(term, intrvl, fs):
self.bounds[term] = (
term.subs({fs: self.bounds[fs][0]}),
term.subs({fs: self.bounds[fs][1]})
)
elif is_decreasing(term, intrvl, fs):
self.bounds[term] = (
term.subs({fs: self.bounds[fs][1]}),
term.subs({fs: self.bounds[fs][0]})
)
else:
return add
if all(term.is_number or term in self.bounds for term in add.args):
bounds = [(term, term) if term.is_number else self.bounds[term] for term in add.args]
largest_abs_guarantee = 0
for lo, hi in bounds:
if lo <= 0 <= hi:
continue
largest_abs_guarantee = max(largest_abs_guarantee,
min(abs(lo), abs(hi)))
new_terms = []
for term, (lo, hi) in zip(add.args, bounds):
if max(abs(lo), abs(hi)) >= largest_abs_guarantee*self.reltol:
new_terms.append(term)
return add.func(*new_terms)
else:
return add
class SeriesApprox(Optimization):
""" Approximates functions by expanding them as a series.
Parameters
==========
bounds : dict
Mapping expressions to length 2 tuple of bounds (low, high).
reltol : number
Threshold for when to ignore a term. Taken relative to the largest
lower bound among bounds.
max_order : int
Largest order to include in series expansion
n_point_checks : int (even)
The validity of an expansion (with respect to reltol) is checked at
discrete points (linearly spaced over the bounds of the variable). The
number of points used in this numerical check is given by this number.
Examples
========
>>> from sympy import sin, pi
>>> from sympy.abc import x, y
>>> from sympy.codegen.rewriting import optimize
>>> from sympy.codegen.approximations import SeriesApprox
>>> bounds = {x: (-.1, .1), y: (pi-1, pi+1)}
>>> series_approx2 = SeriesApprox(bounds, reltol=1e-2)
>>> series_approx3 = SeriesApprox(bounds, reltol=1e-3)
>>> series_approx8 = SeriesApprox(bounds, reltol=1e-8)
>>> expr = sin(x)*sin(y)
>>> optimize(expr, [series_approx2])
x*(-y + (y - pi)**3/6 + pi)
>>> optimize(expr, [series_approx3])
(-x**3/6 + x)*sin(y)
>>> optimize(expr, [series_approx8])
sin(x)*sin(y)
"""
def __init__(self, bounds, reltol, max_order=4, n_point_checks=4, **kwargs):
super().__init__(**kwargs)
self.bounds = bounds
self.reltol = reltol
self.max_order = max_order
if n_point_checks % 2 == 1:
raise ValueError("Checking the solution at expansion point is not helpful")
self.n_point_checks = n_point_checks
self._prec = math.ceil(-math.log10(self.reltol))
def __call__(self, expr):
return expr.factor().replace(self.query, lambda arg: self.value(arg))
def query(self, expr):
return (expr.is_Function and not isinstance(expr, UndefinedFunction)
and len(expr.args) == 1)
def value(self, fexpr):
free_symbols = fexpr.free_symbols
if len(free_symbols) != 1:
return fexpr
symb, = free_symbols
if symb not in self.bounds:
return fexpr
lo, hi = self.bounds[symb]
x0 = (lo + hi)/2
cheapest = None
for n in range(self.max_order+1, 0, -1):
fseri = fexpr.series(symb, x0=x0, n=n).removeO()
n_ok = True
for idx in range(self.n_point_checks):
x = lo + idx*(hi - lo)/(self.n_point_checks - 1)
val = fseri.xreplace({symb: x})
ref = fexpr.xreplace({symb: x})
if abs((1 - val/ref).evalf(self._prec)) > self.reltol:
n_ok = False
break
if n_ok:
cheapest = fseri
else:
break
if cheapest is None:
return fexpr
else:
return cheapest
PK ]ZZZb�"��� �� sympy/codegen/ast.py"""
Types used to represent a full function/module as an Abstract Syntax Tree.
Most types are small, and are merely used as tokens in the AST. A tree diagram
has been included below to illustrate the relationships between the AST types.
AST Type Tree
-------------
::
*Basic*
|
|
CodegenAST
|
|--->AssignmentBase
| |--->Assignment
| |--->AugmentedAssignment
| |--->AddAugmentedAssignment
| |--->SubAugmentedAssignment
| |--->MulAugmentedAssignment
| |--->DivAugmentedAssignment
| |--->ModAugmentedAssignment
|
|--->CodeBlock
|
|
|--->Token
|--->Attribute
|--->For
|--->String
| |--->QuotedString
| |--->Comment
|--->Type
| |--->IntBaseType
| | |--->_SizedIntType
| | |--->SignedIntType
| | |--->UnsignedIntType
| |--->FloatBaseType
| |--->FloatType
| |--->ComplexBaseType
| |--->ComplexType
|--->Node
| |--->Variable
| | |---> Pointer
| |--->FunctionPrototype
| |--->FunctionDefinition
|--->Element
|--->Declaration
|--->While
|--->Scope
|--->Stream
|--->Print
|--->FunctionCall
|--->BreakToken
|--->ContinueToken
|--->NoneToken
|--->Return
Predefined types
----------------
A number of ``Type`` instances are provided in the ``sympy.codegen.ast`` module
for convenience. Perhaps the two most common ones for code-generation (of numeric
codes) are ``float32`` and ``float64`` (known as single and double precision respectively).
There are also precision generic versions of Types (for which the codeprinters selects the
underlying data type at time of printing): ``real``, ``integer``, ``complex_``, ``bool_``.
The other ``Type`` instances defined are:
- ``intc``: Integer type used by C's "int".
- ``intp``: Integer type used by C's "unsigned".
- ``int8``, ``int16``, ``int32``, ``int64``: n-bit integers.
- ``uint8``, ``uint16``, ``uint32``, ``uint64``: n-bit unsigned integers.
- ``float80``: known as "extended precision" on modern x86/amd64 hardware.
- ``complex64``: Complex number represented by two ``float32`` numbers
- ``complex128``: Complex number represented by two ``float64`` numbers
Using the nodes
---------------
It is possible to construct simple algorithms using the AST nodes. Let's construct a loop applying
Newton's method::
>>> from sympy import symbols, cos
>>> from sympy.codegen.ast import While, Assignment, aug_assign, Print, QuotedString
>>> t, dx, x = symbols('tol delta val')
>>> expr = cos(x) - x**3
>>> whl = While(abs(dx) > t, [
... Assignment(dx, -expr/expr.diff(x)),
... aug_assign(x, '+', dx),
... Print([x])
... ])
>>> from sympy import pycode
>>> py_str = pycode(whl)
>>> print(py_str)
while (abs(delta) > tol):
delta = (val**3 - math.cos(val))/(-3*val**2 - math.sin(val))
val += delta
print(val)
>>> import math
>>> tol, val, delta = 1e-5, 0.5, float('inf')
>>> exec(py_str)
1.1121416371
0.909672693737
0.867263818209
0.865477135298
0.865474033111
>>> print('%3.1g' % (math.cos(val) - val**3))
-3e-11
If we want to generate Fortran code for the same while loop we simple call ``fcode``::
>>> from sympy import fcode
>>> print(fcode(whl, standard=2003, source_format='free'))
do while (abs(delta) > tol)
delta = (val**3 - cos(val))/(-3*val**2 - sin(val))
val = val + delta
print *, val
end do
There is a function constructing a loop (or a complete function) like this in
:mod:`sympy.codegen.algorithms`.
"""
from __future__ import annotations
from typing import Any
from collections import defaultdict
from sympy.core.relational import (Ge, Gt, Le, Lt)
from sympy.core import Symbol, Tuple, Dummy
from sympy.core.basic import Basic
from sympy.core.expr import Expr, Atom
from sympy.core.numbers import Float, Integer, oo
from sympy.core.sympify import _sympify, sympify, SympifyError
from sympy.utilities.iterables import (iterable, topological_sort,
numbered_symbols, filter_symbols)
def _mk_Tuple(args):
"""
Create a SymPy Tuple object from an iterable, converting Python strings to
AST strings.
Parameters
==========
args: iterable
Arguments to :class:`sympy.Tuple`.
Returns
=======
sympy.Tuple
"""
args = [String(arg) if isinstance(arg, str) else arg for arg in args]
return Tuple(*args)
class CodegenAST(Basic):
__slots__ = ()
class Token(CodegenAST):
""" Base class for the AST types.
Explanation
===========
Defining fields are set in ``_fields``. Attributes (defined in _fields)
are only allowed to contain instances of Basic (unless atomic, see
``String``). The arguments to ``__new__()`` correspond to the attributes in
the order defined in ``_fields`. The ``defaults`` class attribute is a
dictionary mapping attribute names to their default values.
Subclasses should not need to override the ``__new__()`` method. They may
define a class or static method named ``_construct_<attr>`` for each
attribute to process the value passed to ``__new__()``. Attributes listed
in the class attribute ``not_in_args`` are not passed to :class:`~.Basic`.
"""
__slots__: tuple[str, ...] = ()
_fields = __slots__
defaults: dict[str, Any] = {}
not_in_args: list[str] = []
indented_args = ['body']
@property
def is_Atom(self):
return len(self._fields) == 0
@classmethod
def _get_constructor(cls, attr):
""" Get the constructor function for an attribute by name. """
return getattr(cls, '_construct_%s' % attr, lambda x: x)
@classmethod
def _construct(cls, attr, arg):
""" Construct an attribute value from argument passed to ``__new__()``. """
# arg may be ``NoneToken()``, so comparison is done using == instead of ``is`` operator
if arg == None:
return cls.defaults.get(attr, none)
else:
if isinstance(arg, Dummy): # SymPy's replace uses Dummy instances
return arg
else:
return cls._get_constructor(attr)(arg)
def __new__(cls, *args, **kwargs):
# Pass through existing instances when given as sole argument
if len(args) == 1 and not kwargs and isinstance(args[0], cls):
return args[0]
if len(args) > len(cls._fields):
raise ValueError("Too many arguments (%d), expected at most %d" % (len(args), len(cls._fields)))
attrvals = []
# Process positional arguments
for attrname, argval in zip(cls._fields, args):
if attrname in kwargs:
raise TypeError('Got multiple values for attribute %r' % attrname)
attrvals.append(cls._construct(attrname, argval))
# Process keyword arguments
for attrname in cls._fields[len(args):]:
if attrname in kwargs:
argval = kwargs.pop(attrname)
elif attrname in cls.defaults:
argval = cls.defaults[attrname]
else:
raise TypeError('No value for %r given and attribute has no default' % attrname)
attrvals.append(cls._construct(attrname, argval))
if kwargs:
raise ValueError("Unknown keyword arguments: %s" % ' '.join(kwargs))
# Parent constructor
basic_args = [
val for attr, val in zip(cls._fields, attrvals)
if attr not in cls.not_in_args
]
obj = CodegenAST.__new__(cls, *basic_args)
# Set attributes
for attr, arg in zip(cls._fields, attrvals):
setattr(obj, attr, arg)
return obj
def __eq__(self, other):
if not isinstance(other, self.__class__):
return False
for attr in self._fields:
if getattr(self, attr) != getattr(other, attr):
return False
return True
def _hashable_content(self):
return tuple([getattr(self, attr) for attr in self._fields])
def __hash__(self):
return super().__hash__()
def _joiner(self, k, indent_level):
return (',\n' + ' '*indent_level) if k in self.indented_args else ', '
def _indented(self, printer, k, v, *args, **kwargs):
il = printer._context['indent_level']
def _print(arg):
if isinstance(arg, Token):
return printer._print(arg, *args, joiner=self._joiner(k, il), **kwargs)
else:
return printer._print(arg, *args, **kwargs)
if isinstance(v, Tuple):
joined = self._joiner(k, il).join([_print(arg) for arg in v.args])
if k in self.indented_args:
return '(\n' + ' '*il + joined + ',\n' + ' '*(il - 4) + ')'
else:
return ('({0},)' if len(v.args) == 1 else '({0})').format(joined)
else:
return _print(v)
def _sympyrepr(self, printer, *args, joiner=', ', **kwargs):
from sympy.printing.printer import printer_context
exclude = kwargs.get('exclude', ())
values = [getattr(self, k) for k in self._fields]
indent_level = printer._context.get('indent_level', 0)
arg_reprs = []
for i, (attr, value) in enumerate(zip(self._fields, values)):
if attr in exclude:
continue
# Skip attributes which have the default value
if attr in self.defaults and value == self.defaults[attr]:
continue
ilvl = indent_level + 4 if attr in self.indented_args else 0
with printer_context(printer, indent_level=ilvl):
indented = self._indented(printer, attr, value, *args, **kwargs)
arg_reprs.append(('{1}' if i == 0 else '{0}={1}').format(attr, indented.lstrip()))
return "{}({})".format(self.__class__.__name__, joiner.join(arg_reprs))
_sympystr = _sympyrepr
def __repr__(self): # sympy.core.Basic.__repr__ uses sstr
from sympy.printing import srepr
return srepr(self)
def kwargs(self, exclude=(), apply=None):
""" Get instance's attributes as dict of keyword arguments.
Parameters
==========
exclude : collection of str
Collection of keywords to exclude.
apply : callable, optional
Function to apply to all values.
"""
kwargs = {k: getattr(self, k) for k in self._fields if k not in exclude}
if apply is not None:
return {k: apply(v) for k, v in kwargs.items()}
else:
return kwargs
class BreakToken(Token):
""" Represents 'break' in C/Python ('exit' in Fortran).
Use the premade instance ``break_`` or instantiate manually.
Examples
========
>>> from sympy import ccode, fcode
>>> from sympy.codegen.ast import break_
>>> ccode(break_)
'break'
>>> fcode(break_, source_format='free')
'exit'
"""
break_ = BreakToken()
class ContinueToken(Token):
""" Represents 'continue' in C/Python ('cycle' in Fortran)
Use the premade instance ``continue_`` or instantiate manually.
Examples
========
>>> from sympy import ccode, fcode
>>> from sympy.codegen.ast import continue_
>>> ccode(continue_)
'continue'
>>> fcode(continue_, source_format='free')
'cycle'
"""
continue_ = ContinueToken()
class NoneToken(Token):
""" The AST equivalence of Python's NoneType
The corresponding instance of Python's ``None`` is ``none``.
Examples
========
>>> from sympy.codegen.ast import none, Variable
>>> from sympy import pycode
>>> print(pycode(Variable('x').as_Declaration(value=none)))
x = None
"""
def __eq__(self, other):
return other is None or isinstance(other, NoneToken)
def _hashable_content(self):
return ()
def __hash__(self):
return super().__hash__()
none = NoneToken()
class AssignmentBase(CodegenAST):
""" Abstract base class for Assignment and AugmentedAssignment.
Attributes:
===========
op : str
Symbol for assignment operator, e.g. "=", "+=", etc.
"""
def __new__(cls, lhs, rhs):
lhs = _sympify(lhs)
rhs = _sympify(rhs)
cls._check_args(lhs, rhs)
return super().__new__(cls, lhs, rhs)
@property
def lhs(self):
return self.args[0]
@property
def rhs(self):
return self.args[1]
@classmethod
def _check_args(cls, lhs, rhs):
""" Check arguments to __new__ and raise exception if any problems found.
Derived classes may wish to override this.
"""
from sympy.matrices.expressions.matexpr import (
MatrixElement, MatrixSymbol)
from sympy.tensor.indexed import Indexed
from sympy.tensor.array.expressions import ArrayElement
# Tuple of things that can be on the lhs of an assignment
assignable = (Symbol, MatrixSymbol, MatrixElement, Indexed, Element, Variable,
ArrayElement)
if not isinstance(lhs, assignable):
raise TypeError("Cannot assign to lhs of type %s." % type(lhs))
# Indexed types implement shape, but don't define it until later. This
# causes issues in assignment validation. For now, matrices are defined
# as anything with a shape that is not an Indexed
lhs_is_mat = hasattr(lhs, 'shape') and not isinstance(lhs, Indexed)
rhs_is_mat = hasattr(rhs, 'shape') and not isinstance(rhs, Indexed)
# If lhs and rhs have same structure, then this assignment is ok
if lhs_is_mat:
if not rhs_is_mat:
raise ValueError("Cannot assign a scalar to a matrix.")
elif lhs.shape != rhs.shape:
raise ValueError("Dimensions of lhs and rhs do not align.")
elif rhs_is_mat and not lhs_is_mat:
raise ValueError("Cannot assign a matrix to a scalar.")
class Assignment(AssignmentBase):
"""
Represents variable assignment for code generation.
Parameters
==========
lhs : Expr
SymPy object representing the lhs of the expression. These should be
singular objects, such as one would use in writing code. Notable types
include Symbol, MatrixSymbol, MatrixElement, and Indexed. Types that
subclass these types are also supported.
rhs : Expr
SymPy object representing the rhs of the expression. This can be any
type, provided its shape corresponds to that of the lhs. For example,
a Matrix type can be assigned to MatrixSymbol, but not to Symbol, as
the dimensions will not align.
Examples
========
>>> from sympy import symbols, MatrixSymbol, Matrix
>>> from sympy.codegen.ast import Assignment
>>> x, y, z = symbols('x, y, z')
>>> Assignment(x, y)
Assignment(x, y)
>>> Assignment(x, 0)
Assignment(x, 0)
>>> A = MatrixSymbol('A', 1, 3)
>>> mat = Matrix([x, y, z]).T
>>> Assignment(A, mat)
Assignment(A, Matrix([[x, y, z]]))
>>> Assignment(A[0, 1], x)
Assignment(A[0, 1], x)
"""
op = ':='
class AugmentedAssignment(AssignmentBase):
"""
Base class for augmented assignments.
Attributes:
===========
binop : str
Symbol for binary operation being applied in the assignment, such as "+",
"*", etc.
"""
binop = None # type: str
@property
def op(self):
return self.binop + '='
class AddAugmentedAssignment(AugmentedAssignment):
binop = '+'
class SubAugmentedAssignment(AugmentedAssignment):
binop = '-'
class MulAugmentedAssignment(AugmentedAssignment):
binop = '*'
class DivAugmentedAssignment(AugmentedAssignment):
binop = '/'
class ModAugmentedAssignment(AugmentedAssignment):
binop = '%'
# Mapping from binary op strings to AugmentedAssignment subclasses
augassign_classes = {
cls.binop: cls for cls in [
AddAugmentedAssignment, SubAugmentedAssignment, MulAugmentedAssignment,
DivAugmentedAssignment, ModAugmentedAssignment
]
}
def aug_assign(lhs, op, rhs):
"""
Create 'lhs op= rhs'.
Explanation
===========
Represents augmented variable assignment for code generation. This is a
convenience function. You can also use the AugmentedAssignment classes
directly, like AddAugmentedAssignment(x, y).
Parameters
==========
lhs : Expr
SymPy object representing the lhs of the expression. These should be
singular objects, such as one would use in writing code. Notable types
include Symbol, MatrixSymbol, MatrixElement, and Indexed. Types that
subclass these types are also supported.
op : str
Operator (+, -, /, \\*, %).
rhs : Expr
SymPy object representing the rhs of the expression. This can be any
type, provided its shape corresponds to that of the lhs. For example,
a Matrix type can be assigned to MatrixSymbol, but not to Symbol, as
the dimensions will not align.
Examples
========
>>> from sympy import symbols
>>> from sympy.codegen.ast import aug_assign
>>> x, y = symbols('x, y')
>>> aug_assign(x, '+', y)
AddAugmentedAssignment(x, y)
"""
if op not in augassign_classes:
raise ValueError("Unrecognized operator %s" % op)
return augassign_classes[op](lhs, rhs)
class CodeBlock(CodegenAST):
"""
Represents a block of code.
Explanation
===========
For now only assignments are supported. This restriction will be lifted in
the future.
Useful attributes on this object are:
``left_hand_sides``:
Tuple of left-hand sides of assignments, in order.
``left_hand_sides``:
Tuple of right-hand sides of assignments, in order.
``free_symbols``: Free symbols of the expressions in the right-hand sides
which do not appear in the left-hand side of an assignment.
Useful methods on this object are:
``topological_sort``:
Class method. Return a CodeBlock with assignments
sorted so that variables are assigned before they
are used.
``cse``:
Return a new CodeBlock with common subexpressions eliminated and
pulled out as assignments.
Examples
========
>>> from sympy import symbols, ccode
>>> from sympy.codegen.ast import CodeBlock, Assignment
>>> x, y = symbols('x y')
>>> c = CodeBlock(Assignment(x, 1), Assignment(y, x + 1))
>>> print(ccode(c))
x = 1;
y = x + 1;
"""
def __new__(cls, *args):
left_hand_sides = []
right_hand_sides = []
for i in args:
if isinstance(i, Assignment):
lhs, rhs = i.args
left_hand_sides.append(lhs)
right_hand_sides.append(rhs)
obj = CodegenAST.__new__(cls, *args)
obj.left_hand_sides = Tuple(*left_hand_sides)
obj.right_hand_sides = Tuple(*right_hand_sides)
return obj
def __iter__(self):
return iter(self.args)
def _sympyrepr(self, printer, *args, **kwargs):
il = printer._context.get('indent_level', 0)
joiner = ',\n' + ' '*il
joined = joiner.join(map(printer._print, self.args))
return ('{}(\n'.format(' '*(il-4) + self.__class__.__name__,) +
' '*il + joined + '\n' + ' '*(il - 4) + ')')
_sympystr = _sympyrepr
@property
def free_symbols(self):
return super().free_symbols - set(self.left_hand_sides)
@classmethod
def topological_sort(cls, assignments):
"""
Return a CodeBlock with topologically sorted assignments so that
variables are assigned before they are used.
Examples
========
The existing order of assignments is preserved as much as possible.
This function assumes that variables are assigned to only once.
This is a class constructor so that the default constructor for
CodeBlock can error when variables are used before they are assigned.
>>> from sympy import symbols
>>> from sympy.codegen.ast import CodeBlock, Assignment
>>> x, y, z = symbols('x y z')
>>> assignments = [
... Assignment(x, y + z),
... Assignment(y, z + 1),
... Assignment(z, 2),
... ]
>>> CodeBlock.topological_sort(assignments)
CodeBlock(
Assignment(z, 2),
Assignment(y, z + 1),
Assignment(x, y + z)
)
"""
if not all(isinstance(i, Assignment) for i in assignments):
# Will support more things later
raise NotImplementedError("CodeBlock.topological_sort only supports Assignments")
if any(isinstance(i, AugmentedAssignment) for i in assignments):
raise NotImplementedError("CodeBlock.topological_sort does not yet work with AugmentedAssignments")
# Create a graph where the nodes are assignments and there is a directed edge
# between nodes that use a variable and nodes that assign that
# variable, like
# [(x := 1, y := x + 1), (x := 1, z := y + z), (y := x + 1, z := y + z)]
# If we then topologically sort these nodes, they will be in
# assignment order, like
# x := 1
# y := x + 1
# z := y + z
# A = The nodes
#
# enumerate keeps nodes in the same order they are already in if
# possible. It will also allow us to handle duplicate assignments to
# the same variable when those are implemented.
A = list(enumerate(assignments))
# var_map = {variable: [nodes for which this variable is assigned to]}
# like {x: [(1, x := y + z), (4, x := 2 * w)], ...}
var_map = defaultdict(list)
for node in A:
i, a = node
var_map[a.lhs].append(node)
# E = Edges in the graph
E = []
for dst_node in A:
i, a = dst_node
for s in a.rhs.free_symbols:
for src_node in var_map[s]:
E.append((src_node, dst_node))
ordered_assignments = topological_sort([A, E])
# De-enumerate the result
return cls(*[a for i, a in ordered_assignments])
def cse(self, symbols=None, optimizations=None, postprocess=None,
order='canonical'):
"""
Return a new code block with common subexpressions eliminated.
Explanation
===========
See the docstring of :func:`sympy.simplify.cse_main.cse` for more
information.
Examples
========
>>> from sympy import symbols, sin
>>> from sympy.codegen.ast import CodeBlock, Assignment
>>> x, y, z = symbols('x y z')
>>> c = CodeBlock(
... Assignment(x, 1),
... Assignment(y, sin(x) + 1),
... Assignment(z, sin(x) - 1),
... )
...
>>> c.cse()
CodeBlock(
Assignment(x, 1),
Assignment(x0, sin(x)),
Assignment(y, x0 + 1),
Assignment(z, x0 - 1)
)
"""
from sympy.simplify.cse_main import cse
# Check that the CodeBlock only contains assignments to unique variables
if not all(isinstance(i, Assignment) for i in self.args):
# Will support more things later
raise NotImplementedError("CodeBlock.cse only supports Assignments")
if any(isinstance(i, AugmentedAssignment) for i in self.args):
raise NotImplementedError("CodeBlock.cse does not yet work with AugmentedAssignments")
for i, lhs in enumerate(self.left_hand_sides):
if lhs in self.left_hand_sides[:i]:
raise NotImplementedError("Duplicate assignments to the same "
"variable are not yet supported (%s)" % lhs)
# Ensure new symbols for subexpressions do not conflict with existing
existing_symbols = self.atoms(Symbol)
if symbols is None:
symbols = numbered_symbols()
symbols = filter_symbols(symbols, existing_symbols)
replacements, reduced_exprs = cse(list(self.right_hand_sides),
symbols=symbols, optimizations=optimizations, postprocess=postprocess,
order=order)
new_block = [Assignment(var, expr) for var, expr in
zip(self.left_hand_sides, reduced_exprs)]
new_assignments = [Assignment(var, expr) for var, expr in replacements]
return self.topological_sort(new_assignments + new_block)
class For(Token):
"""Represents a 'for-loop' in the code.
Expressions are of the form:
"for target in iter:
body..."
Parameters
==========
target : symbol
iter : iterable
body : CodeBlock or iterable
! When passed an iterable it is used to instantiate a CodeBlock.
Examples
========
>>> from sympy import symbols, Range
>>> from sympy.codegen.ast import aug_assign, For
>>> x, i, j, k = symbols('x i j k')
>>> for_i = For(i, Range(10), [aug_assign(x, '+', i*j*k)])
>>> for_i # doctest: -NORMALIZE_WHITESPACE
For(i, iterable=Range(0, 10, 1), body=CodeBlock(
AddAugmentedAssignment(x, i*j*k)
))
>>> for_ji = For(j, Range(7), [for_i])
>>> for_ji # doctest: -NORMALIZE_WHITESPACE
For(j, iterable=Range(0, 7, 1), body=CodeBlock(
For(i, iterable=Range(0, 10, 1), body=CodeBlock(
AddAugmentedAssignment(x, i*j*k)
))
))
>>> for_kji =For(k, Range(5), [for_ji])
>>> for_kji # doctest: -NORMALIZE_WHITESPACE
For(k, iterable=Range(0, 5, 1), body=CodeBlock(
For(j, iterable=Range(0, 7, 1), body=CodeBlock(
For(i, iterable=Range(0, 10, 1), body=CodeBlock(
AddAugmentedAssignment(x, i*j*k)
))
))
))
"""
__slots__ = _fields = ('target', 'iterable', 'body')
_construct_target = staticmethod(_sympify)
@classmethod
def _construct_body(cls, itr):
if isinstance(itr, CodeBlock):
return itr
else:
return CodeBlock(*itr)
@classmethod
def _construct_iterable(cls, itr):
if not iterable(itr):
raise TypeError("iterable must be an iterable")
if isinstance(itr, list): # _sympify errors on lists because they are mutable
itr = tuple(itr)
return _sympify(itr)
class String(Atom, Token):
""" SymPy object representing a string.
Atomic object which is not an expression (as opposed to Symbol).
Parameters
==========
text : str
Examples
========
>>> from sympy.codegen.ast import String
>>> f = String('foo')
>>> f
foo
>>> str(f)
'foo'
>>> f.text
'foo'
>>> print(repr(f))
String('foo')
"""
__slots__ = _fields = ('text',)
not_in_args = ['text']
is_Atom = True
@classmethod
def _construct_text(cls, text):
if not isinstance(text, str):
raise TypeError("Argument text is not a string type.")
return text
def _sympystr(self, printer, *args, **kwargs):
return self.text
def kwargs(self, exclude = (), apply = None):
return {}
#to be removed when Atom is given a suitable func
@property
def func(self):
return lambda: self
def _latex(self, printer):
from sympy.printing.latex import latex_escape
return r'\texttt{{"{}"}}'.format(latex_escape(self.text))
class QuotedString(String):
""" Represents a string which should be printed with quotes. """
class Comment(String):
""" Represents a comment. """
class Node(Token):
""" Subclass of Token, carrying the attribute 'attrs' (Tuple)
Examples
========
>>> from sympy.codegen.ast import Node, value_const, pointer_const
>>> n1 = Node([value_const])
>>> n1.attr_params('value_const') # get the parameters of attribute (by name)
()
>>> from sympy.codegen.fnodes import dimension
>>> n2 = Node([value_const, dimension(5, 3)])
>>> n2.attr_params(value_const) # get the parameters of attribute (by Attribute instance)
()
>>> n2.attr_params('dimension') # get the parameters of attribute (by name)
(5, 3)
>>> n2.attr_params(pointer_const) is None
True
"""
__slots__: tuple[str, ...] = ('attrs',)
_fields = __slots__
defaults: dict[str, Any] = {'attrs': Tuple()}
_construct_attrs = staticmethod(_mk_Tuple)
def attr_params(self, looking_for):
""" Returns the parameters of the Attribute with name ``looking_for`` in self.attrs """
for attr in self.attrs:
if str(attr.name) == str(looking_for):
return attr.parameters
class Type(Token):
""" Represents a type.
Explanation
===========
The naming is a super-set of NumPy naming. Type has a classmethod
``from_expr`` which offer type deduction. It also has a method
``cast_check`` which casts the argument to its type, possibly raising an
exception if rounding error is not within tolerances, or if the value is not
representable by the underlying data type (e.g. unsigned integers).
Parameters
==========
name : str
Name of the type, e.g. ``object``, ``int16``, ``float16`` (where the latter two
would use the ``Type`` sub-classes ``IntType`` and ``FloatType`` respectively).
If a ``Type`` instance is given, the said instance is returned.
Examples
========
>>> from sympy.codegen.ast import Type
>>> t = Type.from_expr(42)
>>> t
integer
>>> print(repr(t))
IntBaseType(String('integer'))
>>> from sympy.codegen.ast import uint8
>>> uint8.cast_check(-1) # doctest: +ELLIPSIS
Traceback (most recent call last):
...
ValueError: Minimum value for data type bigger than new value.
>>> from sympy.codegen.ast import float32
>>> v6 = 0.123456
>>> float32.cast_check(v6)
0.123456
>>> v10 = 12345.67894
>>> float32.cast_check(v10) # doctest: +ELLIPSIS
Traceback (most recent call last):
...
ValueError: Casting gives a significantly different value.
>>> boost_mp50 = Type('boost::multiprecision::cpp_dec_float_50')
>>> from sympy import cxxcode
>>> from sympy.codegen.ast import Declaration, Variable
>>> cxxcode(Declaration(Variable('x', type=boost_mp50)))
'boost::multiprecision::cpp_dec_float_50 x'
References
==========
.. [1] https://numpy.org/doc/stable/user/basics.types.html
"""
__slots__: tuple[str, ...] = ('name',)
_fields = __slots__
_construct_name = String
def _sympystr(self, printer, *args, **kwargs):
return str(self.name)
@classmethod
def from_expr(cls, expr):
""" Deduces type from an expression or a ``Symbol``.
Parameters
==========
expr : number or SymPy object
The type will be deduced from type or properties.
Examples
========
>>> from sympy.codegen.ast import Type, integer, complex_
>>> Type.from_expr(2) == integer
True
>>> from sympy import Symbol
>>> Type.from_expr(Symbol('z', complex=True)) == complex_
True
>>> Type.from_expr(sum) # doctest: +ELLIPSIS
Traceback (most recent call last):
...
ValueError: Could not deduce type from expr.
Raises
======
ValueError when type deduction fails.
"""
if isinstance(expr, (float, Float)):
return real
if isinstance(expr, (int, Integer)) or getattr(expr, 'is_integer', False):
return integer
if getattr(expr, 'is_real', False):
return real
if isinstance(expr, complex) or getattr(expr, 'is_complex', False):
return complex_
if isinstance(expr, bool) or getattr(expr, 'is_Relational', False):
return bool_
else:
raise ValueError("Could not deduce type from expr.")
def _check(self, value):
pass
def cast_check(self, value, rtol=None, atol=0, precision_targets=None):
""" Casts a value to the data type of the instance.
Parameters
==========
value : number
rtol : floating point number
Relative tolerance. (will be deduced if not given).
atol : floating point number
Absolute tolerance (in addition to ``rtol``).
type_aliases : dict
Maps substitutions for Type, e.g. {integer: int64, real: float32}
Examples
========
>>> from sympy.codegen.ast import integer, float32, int8
>>> integer.cast_check(3.0) == 3
True
>>> float32.cast_check(1e-40) # doctest: +ELLIPSIS
Traceback (most recent call last):
...
ValueError: Minimum value for data type bigger than new value.
>>> int8.cast_check(256) # doctest: +ELLIPSIS
Traceback (most recent call last):
...
ValueError: Maximum value for data type smaller than new value.
>>> v10 = 12345.67894
>>> float32.cast_check(v10) # doctest: +ELLIPSIS
Traceback (most recent call last):
...
ValueError: Casting gives a significantly different value.
>>> from sympy.codegen.ast import float64
>>> float64.cast_check(v10)
12345.67894
>>> from sympy import Float
>>> v18 = Float('0.123456789012345646')
>>> float64.cast_check(v18)
Traceback (most recent call last):
...
ValueError: Casting gives a significantly different value.
>>> from sympy.codegen.ast import float80
>>> float80.cast_check(v18)
0.123456789012345649
"""
val = sympify(value)
ten = Integer(10)
exp10 = getattr(self, 'decimal_dig', None)
if rtol is None:
rtol = 1e-15 if exp10 is None else 2.0*ten**(-exp10)
def tol(num):
return atol + rtol*abs(num)
new_val = self.cast_nocheck(value)
self._check(new_val)
delta = new_val - val
if abs(delta) > tol(val): # rounding, e.g. int(3.5) != 3.5
raise ValueError("Casting gives a significantly different value.")
return new_val
def _latex(self, printer):
from sympy.printing.latex import latex_escape
type_name = latex_escape(self.__class__.__name__)
name = latex_escape(self.name.text)
return r"\text{{{}}}\left(\texttt{{{}}}\right)".format(type_name, name)
class IntBaseType(Type):
""" Integer base type, contains no size information. """
__slots__ = ()
cast_nocheck = lambda self, i: Integer(int(i))
class _SizedIntType(IntBaseType):
__slots__ = ('nbits',)
_fields = Type._fields + __slots__
_construct_nbits = Integer
def _check(self, value):
if value < self.min:
raise ValueError("Value is too small: %d < %d" % (value, self.min))
if value > self.max:
raise ValueError("Value is too big: %d > %d" % (value, self.max))
class SignedIntType(_SizedIntType):
""" Represents a signed integer type. """
__slots__ = ()
@property
def min(self):
return -2**(self.nbits-1)
@property
def max(self):
return 2**(self.nbits-1) - 1
class UnsignedIntType(_SizedIntType):
""" Represents an unsigned integer type. """
__slots__ = ()
@property
def min(self):
return 0
@property
def max(self):
return 2**self.nbits - 1
two = Integer(2)
class FloatBaseType(Type):
""" Represents a floating point number type. """
__slots__ = ()
cast_nocheck = Float
class FloatType(FloatBaseType):
""" Represents a floating point type with fixed bit width.
Base 2 & one sign bit is assumed.
Parameters
==========
name : str
Name of the type.
nbits : integer
Number of bits used (storage).
nmant : integer
Number of bits used to represent the mantissa.
nexp : integer
Number of bits used to represent the mantissa.
Examples
========
>>> from sympy import S
>>> from sympy.codegen.ast import FloatType
>>> half_precision = FloatType('f16', nbits=16, nmant=10, nexp=5)
>>> half_precision.max
65504
>>> half_precision.tiny == S(2)**-14
True
>>> half_precision.eps == S(2)**-10
True
>>> half_precision.dig == 3
True
>>> half_precision.decimal_dig == 5
True
>>> half_precision.cast_check(1.0)
1.0
>>> half_precision.cast_check(1e5) # doctest: +ELLIPSIS
Traceback (most recent call last):
...
ValueError: Maximum value for data type smaller than new value.
"""
__slots__ = ('nbits', 'nmant', 'nexp',)
_fields = Type._fields + __slots__
_construct_nbits = _construct_nmant = _construct_nexp = Integer
@property
def max_exponent(self):
""" The largest positive number n, such that 2**(n - 1) is a representable finite value. """
# cf. C++'s ``std::numeric_limits::max_exponent``
return two**(self.nexp - 1)
@property
def min_exponent(self):
""" The lowest negative number n, such that 2**(n - 1) is a valid normalized number. """
# cf. C++'s ``std::numeric_limits::min_exponent``
return 3 - self.max_exponent
@property
def max(self):
""" Maximum value representable. """
return (1 - two**-(self.nmant+1))*two**self.max_exponent
@property
def tiny(self):
""" The minimum positive normalized value. """
# See C macros: FLT_MIN, DBL_MIN, LDBL_MIN
# or C++'s ``std::numeric_limits::min``
# or numpy.finfo(dtype).tiny
return two**(self.min_exponent - 1)
@property
def eps(self):
""" Difference between 1.0 and the next representable value. """
return two**(-self.nmant)
@property
def dig(self):
""" Number of decimal digits that are guaranteed to be preserved in text.
When converting text -> float -> text, you are guaranteed that at least ``dig``
number of digits are preserved with respect to rounding or overflow.
"""
from sympy.functions import floor, log
return floor(self.nmant * log(2)/log(10))
@property
def decimal_dig(self):
""" Number of digits needed to store & load without loss.
Explanation
===========
Number of decimal digits needed to guarantee that two consecutive conversions
(float -> text -> float) to be idempotent. This is useful when one do not want
to loose precision due to rounding errors when storing a floating point value
as text.
"""
from sympy.functions import ceiling, log
return ceiling((self.nmant + 1) * log(2)/log(10) + 1)
def cast_nocheck(self, value):
""" Casts without checking if out of bounds or subnormal. """
if value == oo: # float(oo) or oo
return float(oo)
elif value == -oo: # float(-oo) or -oo
return float(-oo)
return Float(str(sympify(value).evalf(self.decimal_dig)), self.decimal_dig)
def _check(self, value):
if value < -self.max:
raise ValueError("Value is too small: %d < %d" % (value, -self.max))
if value > self.max:
raise ValueError("Value is too big: %d > %d" % (value, self.max))
if abs(value) < self.tiny:
raise ValueError("Smallest (absolute) value for data type bigger than new value.")
class ComplexBaseType(FloatBaseType):
__slots__ = ()
def cast_nocheck(self, value):
""" Casts without checking if out of bounds or subnormal. """
from sympy.functions import re, im
return (
super().cast_nocheck(re(value)) +
super().cast_nocheck(im(value))*1j
)
def _check(self, value):
from sympy.functions import re, im
super()._check(re(value))
super()._check(im(value))
class ComplexType(ComplexBaseType, FloatType):
""" Represents a complex floating point number. """
__slots__ = ()
# NumPy types:
intc = IntBaseType('intc')
intp = IntBaseType('intp')
int8 = SignedIntType('int8', 8)
int16 = SignedIntType('int16', 16)
int32 = SignedIntType('int32', 32)
int64 = SignedIntType('int64', 64)
uint8 = UnsignedIntType('uint8', 8)
uint16 = UnsignedIntType('uint16', 16)
uint32 = UnsignedIntType('uint32', 32)
uint64 = UnsignedIntType('uint64', 64)
float16 = FloatType('float16', 16, nexp=5, nmant=10) # IEEE 754 binary16, Half precision
float32 = FloatType('float32', 32, nexp=8, nmant=23) # IEEE 754 binary32, Single precision
float64 = FloatType('float64', 64, nexp=11, nmant=52) # IEEE 754 binary64, Double precision
float80 = FloatType('float80', 80, nexp=15, nmant=63) # x86 extended precision (1 integer part bit), "long double"
float128 = FloatType('float128', 128, nexp=15, nmant=112) # IEEE 754 binary128, Quadruple precision
float256 = FloatType('float256', 256, nexp=19, nmant=236) # IEEE 754 binary256, Octuple precision
complex64 = ComplexType('complex64', nbits=64, **float32.kwargs(exclude=('name', 'nbits')))
complex128 = ComplexType('complex128', nbits=128, **float64.kwargs(exclude=('name', 'nbits')))
# Generic types (precision may be chosen by code printers):
untyped = Type('untyped')
real = FloatBaseType('real')
integer = IntBaseType('integer')
complex_ = ComplexBaseType('complex')
bool_ = Type('bool')
class Attribute(Token):
""" Attribute (possibly parametrized)
For use with :class:`sympy.codegen.ast.Node` (which takes instances of
``Attribute`` as ``attrs``).
Parameters
==========
name : str
parameters : Tuple
Examples
========
>>> from sympy.codegen.ast import Attribute
>>> volatile = Attribute('volatile')
>>> volatile
volatile
>>> print(repr(volatile))
Attribute(String('volatile'))
>>> a = Attribute('foo', [1, 2, 3])
>>> a
foo(1, 2, 3)
>>> a.parameters == (1, 2, 3)
True
"""
__slots__ = _fields = ('name', 'parameters')
defaults = {'parameters': Tuple()}
_construct_name = String
_construct_parameters = staticmethod(_mk_Tuple)
def _sympystr(self, printer, *args, **kwargs):
result = str(self.name)
if self.parameters:
result += '(%s)' % ', '.join((printer._print(
arg, *args, **kwargs) for arg in self.parameters))
return result
value_const = Attribute('value_const')
pointer_const = Attribute('pointer_const')
class Variable(Node):
""" Represents a variable.
Parameters
==========
symbol : Symbol
type : Type (optional)
Type of the variable.
attrs : iterable of Attribute instances
Will be stored as a Tuple.
Examples
========
>>> from sympy import Symbol
>>> from sympy.codegen.ast import Variable, float32, integer
>>> x = Symbol('x')
>>> v = Variable(x, type=float32)
>>> v.attrs
()
>>> v == Variable('x')
False
>>> v == Variable('x', type=float32)
True
>>> v
Variable(x, type=float32)
One may also construct a ``Variable`` instance with the type deduced from
assumptions about the symbol using the ``deduced`` classmethod:
>>> i = Symbol('i', integer=True)
>>> v = Variable.deduced(i)
>>> v.type == integer
True
>>> v == Variable('i')
False
>>> from sympy.codegen.ast import value_const
>>> value_const in v.attrs
False
>>> w = Variable('w', attrs=[value_const])
>>> w
Variable(w, attrs=(value_const,))
>>> value_const in w.attrs
True
>>> w.as_Declaration(value=42)
Declaration(Variable(w, value=42, attrs=(value_const,)))
"""
__slots__ = ('symbol', 'type', 'value')
_fields = __slots__ + Node._fields
defaults = Node.defaults.copy()
defaults.update({'type': untyped, 'value': none})
_construct_symbol = staticmethod(sympify)
_construct_value = staticmethod(sympify)
@classmethod
def deduced(cls, symbol, value=None, attrs=Tuple(), cast_check=True):
""" Alt. constructor with type deduction from ``Type.from_expr``.
Deduces type primarily from ``symbol``, secondarily from ``value``.
Parameters
==========
symbol : Symbol
value : expr
(optional) value of the variable.
attrs : iterable of Attribute instances
cast_check : bool
Whether to apply ``Type.cast_check`` on ``value``.
Examples
========
>>> from sympy import Symbol
>>> from sympy.codegen.ast import Variable, complex_
>>> n = Symbol('n', integer=True)
>>> str(Variable.deduced(n).type)
'integer'
>>> x = Symbol('x', real=True)
>>> v = Variable.deduced(x)
>>> v.type
real
>>> z = Symbol('z', complex=True)
>>> Variable.deduced(z).type == complex_
True
"""
if isinstance(symbol, Variable):
return symbol
try:
type_ = Type.from_expr(symbol)
except ValueError:
type_ = Type.from_expr(value)
if value is not None and cast_check:
value = type_.cast_check(value)
return cls(symbol, type=type_, value=value, attrs=attrs)
def as_Declaration(self, **kwargs):
""" Convenience method for creating a Declaration instance.
Explanation
===========
If the variable of the Declaration need to wrap a modified
variable keyword arguments may be passed (overriding e.g.
the ``value`` of the Variable instance).
Examples
========
>>> from sympy.codegen.ast import Variable, NoneToken
>>> x = Variable('x')
>>> decl1 = x.as_Declaration()
>>> # value is special NoneToken() which must be tested with == operator
>>> decl1.variable.value is None # won't work
False
>>> decl1.variable.value == None # not PEP-8 compliant
True
>>> decl1.variable.value == NoneToken() # OK
True
>>> decl2 = x.as_Declaration(value=42.0)
>>> decl2.variable.value == 42.0
True
"""
kw = self.kwargs()
kw.update(kwargs)
return Declaration(self.func(**kw))
def _relation(self, rhs, op):
try:
rhs = _sympify(rhs)
except SympifyError:
raise TypeError("Invalid comparison %s < %s" % (self, rhs))
return op(self, rhs, evaluate=False)
__lt__ = lambda self, other: self._relation(other, Lt)
__le__ = lambda self, other: self._relation(other, Le)
__ge__ = lambda self, other: self._relation(other, Ge)
__gt__ = lambda self, other: self._relation(other, Gt)
class Pointer(Variable):
""" Represents a pointer. See ``Variable``.
Examples
========
Can create instances of ``Element``:
>>> from sympy import Symbol
>>> from sympy.codegen.ast import Pointer
>>> i = Symbol('i', integer=True)
>>> p = Pointer('x')
>>> p[i+1]
Element(x, indices=(i + 1,))
"""
__slots__ = ()
def __getitem__(self, key):
try:
return Element(self.symbol, key)
except TypeError:
return Element(self.symbol, (key,))
class Element(Token):
""" Element in (a possibly N-dimensional) array.
Examples
========
>>> from sympy.codegen.ast import Element
>>> elem = Element('x', 'ijk')
>>> elem.symbol.name == 'x'
True
>>> elem.indices
(i, j, k)
>>> from sympy import ccode
>>> ccode(elem)
'x[i][j][k]'
>>> ccode(Element('x', 'ijk', strides='lmn', offset='o'))
'x[i*l + j*m + k*n + o]'
"""
__slots__ = _fields = ('symbol', 'indices', 'strides', 'offset')
defaults = {'strides': none, 'offset': none}
_construct_symbol = staticmethod(sympify)
_construct_indices = staticmethod(lambda arg: Tuple(*arg))
_construct_strides = staticmethod(lambda arg: Tuple(*arg))
_construct_offset = staticmethod(sympify)
class Declaration(Token):
""" Represents a variable declaration
Parameters
==========
variable : Variable
Examples
========
>>> from sympy.codegen.ast import Declaration, NoneToken, untyped
>>> z = Declaration('z')
>>> z.variable.type == untyped
True
>>> # value is special NoneToken() which must be tested with == operator
>>> z.variable.value is None # won't work
False
>>> z.variable.value == None # not PEP-8 compliant
True
>>> z.variable.value == NoneToken() # OK
True
"""
__slots__ = _fields = ('variable',)
_construct_variable = Variable
class While(Token):
""" Represents a 'for-loop' in the code.
Expressions are of the form:
"while condition:
body..."
Parameters
==========
condition : expression convertible to Boolean
body : CodeBlock or iterable
When passed an iterable it is used to instantiate a CodeBlock.
Examples
========
>>> from sympy import symbols, Gt, Abs
>>> from sympy.codegen import aug_assign, Assignment, While
>>> x, dx = symbols('x dx')
>>> expr = 1 - x**2
>>> whl = While(Gt(Abs(dx), 1e-9), [
... Assignment(dx, -expr/expr.diff(x)),
... aug_assign(x, '+', dx)
... ])
"""
__slots__ = _fields = ('condition', 'body')
_construct_condition = staticmethod(lambda cond: _sympify(cond))
@classmethod
def _construct_body(cls, itr):
if isinstance(itr, CodeBlock):
return itr
else:
return CodeBlock(*itr)
class Scope(Token):
""" Represents a scope in the code.
Parameters
==========
body : CodeBlock or iterable
When passed an iterable it is used to instantiate a CodeBlock.
"""
__slots__ = _fields = ('body',)
@classmethod
def _construct_body(cls, itr):
if isinstance(itr, CodeBlock):
return itr
else:
return CodeBlock(*itr)
class Stream(Token):
""" Represents a stream.
There are two predefined Stream instances ``stdout`` & ``stderr``.
Parameters
==========
name : str
Examples
========
>>> from sympy import pycode, Symbol
>>> from sympy.codegen.ast import Print, stderr, QuotedString
>>> print(pycode(Print(['x'], file=stderr)))
print(x, file=sys.stderr)
>>> x = Symbol('x')
>>> print(pycode(Print([QuotedString('x')], file=stderr))) # print literally "x"
print("x", file=sys.stderr)
"""
__slots__ = _fields = ('name',)
_construct_name = String
stdout = Stream('stdout')
stderr = Stream('stderr')
class Print(Token):
r""" Represents print command in the code.
Parameters
==========
formatstring : str
*args : Basic instances (or convertible to such through sympify)
Examples
========
>>> from sympy.codegen.ast import Print
>>> from sympy import pycode
>>> print(pycode(Print('x y'.split(), "coordinate: %12.5g %12.5g\\n")))
print("coordinate: %12.5g %12.5g\n" % (x, y), end="")
"""
__slots__ = _fields = ('print_args', 'format_string', 'file')
defaults = {'format_string': none, 'file': none}
_construct_print_args = staticmethod(_mk_Tuple)
_construct_format_string = QuotedString
_construct_file = Stream
class FunctionPrototype(Node):
""" Represents a function prototype
Allows the user to generate forward declaration in e.g. C/C++.
Parameters
==========
return_type : Type
name : str
parameters: iterable of Variable instances
attrs : iterable of Attribute instances
Examples
========
>>> from sympy import ccode, symbols
>>> from sympy.codegen.ast import real, FunctionPrototype
>>> x, y = symbols('x y', real=True)
>>> fp = FunctionPrototype(real, 'foo', [x, y])
>>> ccode(fp)
'double foo(double x, double y)'
"""
__slots__ = ('return_type', 'name', 'parameters')
_fields: tuple[str, ...] = __slots__ + Node._fields
_construct_return_type = Type
_construct_name = String
@staticmethod
def _construct_parameters(args):
def _var(arg):
if isinstance(arg, Declaration):
return arg.variable
elif isinstance(arg, Variable):
return arg
else:
return Variable.deduced(arg)
return Tuple(*map(_var, args))
@classmethod
def from_FunctionDefinition(cls, func_def):
if not isinstance(func_def, FunctionDefinition):
raise TypeError("func_def is not an instance of FunctionDefinition")
return cls(**func_def.kwargs(exclude=('body',)))
class FunctionDefinition(FunctionPrototype):
""" Represents a function definition in the code.
Parameters
==========
return_type : Type
name : str
parameters: iterable of Variable instances
body : CodeBlock or iterable
attrs : iterable of Attribute instances
Examples
========
>>> from sympy import ccode, symbols
>>> from sympy.codegen.ast import real, FunctionPrototype
>>> x, y = symbols('x y', real=True)
>>> fp = FunctionPrototype(real, 'foo', [x, y])
>>> ccode(fp)
'double foo(double x, double y)'
>>> from sympy.codegen.ast import FunctionDefinition, Return
>>> body = [Return(x*y)]
>>> fd = FunctionDefinition.from_FunctionPrototype(fp, body)
>>> print(ccode(fd))
double foo(double x, double y){
return x*y;
}
"""
__slots__ = ('body', )
_fields = FunctionPrototype._fields[:-1] + __slots__ + Node._fields
@classmethod
def _construct_body(cls, itr):
if isinstance(itr, CodeBlock):
return itr
else:
return CodeBlock(*itr)
@classmethod
def from_FunctionPrototype(cls, func_proto, body):
if not isinstance(func_proto, FunctionPrototype):
raise TypeError("func_proto is not an instance of FunctionPrototype")
return cls(body=body, **func_proto.kwargs())
class Return(Token):
""" Represents a return command in the code.
Parameters
==========
return : Basic
Examples
========
>>> from sympy.codegen.ast import Return
>>> from sympy.printing.pycode import pycode
>>> from sympy import Symbol
>>> x = Symbol('x')
>>> print(pycode(Return(x)))
return x
"""
__slots__ = _fields = ('return',)
_construct_return=staticmethod(_sympify)
class FunctionCall(Token, Expr):
""" Represents a call to a function in the code.
Parameters
==========
name : str
function_args : Tuple
Examples
========
>>> from sympy.codegen.ast import FunctionCall
>>> from sympy import pycode
>>> fcall = FunctionCall('foo', 'bar baz'.split())
>>> print(pycode(fcall))
foo(bar, baz)
"""
__slots__ = _fields = ('name', 'function_args')
_construct_name = String
_construct_function_args = staticmethod(lambda args: Tuple(*args))
class Raise(Token):
""" Prints as 'raise ...' in Python, 'throw ...' in C++"""
__slots__ = _fields = ('exception',)
class RuntimeError_(Token):
""" Represents 'std::runtime_error' in C++ and 'RuntimeError' in Python.
Note that the latter is uncommon, and you might want to use e.g. ValueError.
"""
__slots__ = _fields = ('message',)
_construct_message = String
PK ]ZZZ�w��K. K. sympy/codegen/cfunctions.py"""
This module contains SymPy functions mathcin corresponding to special math functions in the
C standard library (since C99, also available in C++11).
The functions defined in this module allows the user to express functions such as ``expm1``
as a SymPy function for symbolic manipulation.
"""
from sympy.core.function import ArgumentIndexError, Function
from sympy.core.numbers import Rational
from sympy.core.power import Pow
from sympy.core.singleton import S
from sympy.functions.elementary.exponential import exp, log
from sympy.functions.elementary.miscellaneous import sqrt
def _expm1(x):
return exp(x) - S.One
class expm1(Function):
"""
Represents the exponential function minus one.
Explanation
===========
The benefit of using ``expm1(x)`` over ``exp(x) - 1``
is that the latter is prone to cancellation under finite precision
arithmetic when x is close to zero.
Examples
========
>>> from sympy.abc import x
>>> from sympy.codegen.cfunctions import expm1
>>> '%.0e' % expm1(1e-99).evalf()
'1e-99'
>>> from math import exp
>>> exp(1e-99) - 1
0.0
>>> expm1(x).diff(x)
exp(x)
See Also
========
log1p
"""
nargs = 1
def fdiff(self, argindex=1):
"""
Returns the first derivative of this function.
"""
if argindex == 1:
return exp(*self.args)
else:
raise ArgumentIndexError(self, argindex)
def _eval_expand_func(self, **hints):
return _expm1(*self.args)
def _eval_rewrite_as_exp(self, arg, **kwargs):
return exp(arg) - S.One
_eval_rewrite_as_tractable = _eval_rewrite_as_exp
@classmethod
def eval(cls, arg):
exp_arg = exp.eval(arg)
if exp_arg is not None:
return exp_arg - S.One
def _eval_is_real(self):
return self.args[0].is_real
def _eval_is_finite(self):
return self.args[0].is_finite
def _log1p(x):
return log(x + S.One)
class log1p(Function):
"""
Represents the natural logarithm of a number plus one.
Explanation
===========
The benefit of using ``log1p(x)`` over ``log(x + 1)``
is that the latter is prone to cancellation under finite precision
arithmetic when x is close to zero.
Examples
========
>>> from sympy.abc import x
>>> from sympy.codegen.cfunctions import log1p
>>> from sympy import expand_log
>>> '%.0e' % expand_log(log1p(1e-99)).evalf()
'1e-99'
>>> from math import log
>>> log(1 + 1e-99)
0.0
>>> log1p(x).diff(x)
1/(x + 1)
See Also
========
expm1
"""
nargs = 1
def fdiff(self, argindex=1):
"""
Returns the first derivative of this function.
"""
if argindex == 1:
return S.One/(self.args[0] + S.One)
else:
raise ArgumentIndexError(self, argindex)
def _eval_expand_func(self, **hints):
return _log1p(*self.args)
def _eval_rewrite_as_log(self, arg, **kwargs):
return _log1p(arg)
_eval_rewrite_as_tractable = _eval_rewrite_as_log
@classmethod
def eval(cls, arg):
if arg.is_Rational:
return log(arg + S.One)
elif not arg.is_Float: # not safe to add 1 to Float
return log.eval(arg + S.One)
elif arg.is_number:
return log(Rational(arg) + S.One)
def _eval_is_real(self):
return (self.args[0] + S.One).is_nonnegative
def _eval_is_finite(self):
if (self.args[0] + S.One).is_zero:
return False
return self.args[0].is_finite
def _eval_is_positive(self):
return self.args[0].is_positive
def _eval_is_zero(self):
return self.args[0].is_zero
def _eval_is_nonnegative(self):
return self.args[0].is_nonnegative
_Two = S(2)
def _exp2(x):
return Pow(_Two, x)
class exp2(Function):
"""
Represents the exponential function with base two.
Explanation
===========
The benefit of using ``exp2(x)`` over ``2**x``
is that the latter is not as efficient under finite precision
arithmetic.
Examples
========
>>> from sympy.abc import x
>>> from sympy.codegen.cfunctions import exp2
>>> exp2(2).evalf() == 4.0
True
>>> exp2(x).diff(x)
log(2)*exp2(x)
See Also
========
log2
"""
nargs = 1
def fdiff(self, argindex=1):
"""
Returns the first derivative of this function.
"""
if argindex == 1:
return self*log(_Two)
else:
raise ArgumentIndexError(self, argindex)
def _eval_rewrite_as_Pow(self, arg, **kwargs):
return _exp2(arg)
_eval_rewrite_as_tractable = _eval_rewrite_as_Pow
def _eval_expand_func(self, **hints):
return _exp2(*self.args)
@classmethod
def eval(cls, arg):
if arg.is_number:
return _exp2(arg)
def _log2(x):
return log(x)/log(_Two)
class log2(Function):
"""
Represents the logarithm function with base two.
Explanation
===========
The benefit of using ``log2(x)`` over ``log(x)/log(2)``
is that the latter is not as efficient under finite precision
arithmetic.
Examples
========
>>> from sympy.abc import x
>>> from sympy.codegen.cfunctions import log2
>>> log2(4).evalf() == 2.0
True
>>> log2(x).diff(x)
1/(x*log(2))
See Also
========
exp2
log10
"""
nargs = 1
def fdiff(self, argindex=1):
"""
Returns the first derivative of this function.
"""
if argindex == 1:
return S.One/(log(_Two)*self.args[0])
else:
raise ArgumentIndexError(self, argindex)
@classmethod
def eval(cls, arg):
if arg.is_number:
result = log.eval(arg, base=_Two)
if result.is_Atom:
return result
elif arg.is_Pow and arg.base == _Two:
return arg.exp
def _eval_evalf(self, *args, **kwargs):
return self.rewrite(log).evalf(*args, **kwargs)
def _eval_expand_func(self, **hints):
return _log2(*self.args)
def _eval_rewrite_as_log(self, arg, **kwargs):
return _log2(arg)
_eval_rewrite_as_tractable = _eval_rewrite_as_log
def _fma(x, y, z):
return x*y + z
class fma(Function):
"""
Represents "fused multiply add".
Explanation
===========
The benefit of using ``fma(x, y, z)`` over ``x*y + z``
is that, under finite precision arithmetic, the former is
supported by special instructions on some CPUs.
Examples
========
>>> from sympy.abc import x, y, z
>>> from sympy.codegen.cfunctions import fma
>>> fma(x, y, z).diff(x)
y
"""
nargs = 3
def fdiff(self, argindex=1):
"""
Returns the first derivative of this function.
"""
if argindex in (1, 2):
return self.args[2 - argindex]
elif argindex == 3:
return S.One
else:
raise ArgumentIndexError(self, argindex)
def _eval_expand_func(self, **hints):
return _fma(*self.args)
def _eval_rewrite_as_tractable(self, arg, limitvar=None, **kwargs):
return _fma(arg)
_Ten = S(10)
def _log10(x):
return log(x)/log(_Ten)
class log10(Function):
"""
Represents the logarithm function with base ten.
Examples
========
>>> from sympy.abc import x
>>> from sympy.codegen.cfunctions import log10
>>> log10(100).evalf() == 2.0
True
>>> log10(x).diff(x)
1/(x*log(10))
See Also
========
log2
"""
nargs = 1
def fdiff(self, argindex=1):
"""
Returns the first derivative of this function.
"""
if argindex == 1:
return S.One/(log(_Ten)*self.args[0])
else:
raise ArgumentIndexError(self, argindex)
@classmethod
def eval(cls, arg):
if arg.is_number:
result = log.eval(arg, base=_Ten)
if result.is_Atom:
return result
elif arg.is_Pow and arg.base == _Ten:
return arg.exp
def _eval_expand_func(self, **hints):
return _log10(*self.args)
def _eval_rewrite_as_log(self, arg, **kwargs):
return _log10(arg)
_eval_rewrite_as_tractable = _eval_rewrite_as_log
def _Sqrt(x):
return Pow(x, S.Half)
class Sqrt(Function): # 'sqrt' already defined in sympy.functions.elementary.miscellaneous
"""
Represents the square root function.
Explanation
===========
The reason why one would use ``Sqrt(x)`` over ``sqrt(x)``
is that the latter is internally represented as ``Pow(x, S.Half)`` which
may not be what one wants when doing code-generation.
Examples
========
>>> from sympy.abc import x
>>> from sympy.codegen.cfunctions import Sqrt
>>> Sqrt(x)
Sqrt(x)
>>> Sqrt(x).diff(x)
1/(2*sqrt(x))
See Also
========
Cbrt
"""
nargs = 1
def fdiff(self, argindex=1):
"""
Returns the first derivative of this function.
"""
if argindex == 1:
return Pow(self.args[0], Rational(-1, 2))/_Two
else:
raise ArgumentIndexError(self, argindex)
def _eval_expand_func(self, **hints):
return _Sqrt(*self.args)
def _eval_rewrite_as_Pow(self, arg, **kwargs):
return _Sqrt(arg)
_eval_rewrite_as_tractable = _eval_rewrite_as_Pow
def _Cbrt(x):
return Pow(x, Rational(1, 3))
class Cbrt(Function): # 'cbrt' already defined in sympy.functions.elementary.miscellaneous
"""
Represents the cube root function.
Explanation
===========
The reason why one would use ``Cbrt(x)`` over ``cbrt(x)``
is that the latter is internally represented as ``Pow(x, Rational(1, 3))`` which
may not be what one wants when doing code-generation.
Examples
========
>>> from sympy.abc import x
>>> from sympy.codegen.cfunctions import Cbrt
>>> Cbrt(x)
Cbrt(x)
>>> Cbrt(x).diff(x)
1/(3*x**(2/3))
See Also
========
Sqrt
"""
nargs = 1
def fdiff(self, argindex=1):
"""
Returns the first derivative of this function.
"""
if argindex == 1:
return Pow(self.args[0], Rational(-_Two/3))/3
else:
raise ArgumentIndexError(self, argindex)
def _eval_expand_func(self, **hints):
return _Cbrt(*self.args)
def _eval_rewrite_as_Pow(self, arg, **kwargs):
return _Cbrt(arg)
_eval_rewrite_as_tractable = _eval_rewrite_as_Pow
def _hypot(x, y):
return sqrt(Pow(x, 2) + Pow(y, 2))
class hypot(Function):
"""
Represents the hypotenuse function.
Explanation
===========
The hypotenuse function is provided by e.g. the math library
in the C99 standard, hence one may want to represent the function
symbolically when doing code-generation.
Examples
========
>>> from sympy.abc import x, y
>>> from sympy.codegen.cfunctions import hypot
>>> hypot(3, 4).evalf() == 5.0
True
>>> hypot(x, y)
hypot(x, y)
>>> hypot(x, y).diff(x)
x/hypot(x, y)
"""
nargs = 2
def fdiff(self, argindex=1):
"""
Returns the first derivative of this function.
"""
if argindex in (1, 2):
return 2*self.args[argindex-1]/(_Two*self.func(*self.args))
else:
raise ArgumentIndexError(self, argindex)
def _eval_expand_func(self, **hints):
return _hypot(*self.args)
def _eval_rewrite_as_Pow(self, arg, **kwargs):
return _hypot(arg)
_eval_rewrite_as_tractable = _eval_rewrite_as_Pow
class isnan(Function):
nargs = 1
PK ]ZZZ8,1�Q
Q
sympy/codegen/cnodes.py"""
AST nodes specific to the C family of languages
"""
from sympy.codegen.ast import (
Attribute, Declaration, Node, String, Token, Type, none,
FunctionCall, CodeBlock
)
from sympy.core.basic import Basic
from sympy.core.containers import Tuple
from sympy.core.sympify import sympify
void = Type('void')
restrict = Attribute('restrict') # guarantees no pointer aliasing
volatile = Attribute('volatile')
static = Attribute('static')
def alignof(arg):
""" Generate of FunctionCall instance for calling 'alignof' """
return FunctionCall('alignof', [String(arg) if isinstance(arg, str) else arg])
def sizeof(arg):
""" Generate of FunctionCall instance for calling 'sizeof'
Examples
========
>>> from sympy.codegen.ast import real
>>> from sympy.codegen.cnodes import sizeof
>>> from sympy import ccode
>>> ccode(sizeof(real))
'sizeof(double)'
"""
return FunctionCall('sizeof', [String(arg) if isinstance(arg, str) else arg])
class CommaOperator(Basic):
""" Represents the comma operator in C """
def __new__(cls, *args):
return Basic.__new__(cls, *[sympify(arg) for arg in args])
class Label(Node):
""" Label for use with e.g. goto statement.
Examples
========
>>> from sympy import ccode, Symbol
>>> from sympy.codegen.cnodes import Label, PreIncrement
>>> print(ccode(Label('foo')))
foo:
>>> print(ccode(Label('bar', [PreIncrement(Symbol('a'))])))
bar:
++(a);
"""
__slots__ = _fields = ('name', 'body')
defaults = {'body': none}
_construct_name = String
@classmethod
def _construct_body(cls, itr):
if isinstance(itr, CodeBlock):
return itr
else:
return CodeBlock(*itr)
class goto(Token):
""" Represents goto in C """
__slots__ = _fields = ('label',)
_construct_label = Label
class PreDecrement(Basic):
""" Represents the pre-decrement operator
Examples
========
>>> from sympy.abc import x
>>> from sympy.codegen.cnodes import PreDecrement
>>> from sympy import ccode
>>> ccode(PreDecrement(x))
'--(x)'
"""
nargs = 1
class PostDecrement(Basic):
""" Represents the post-decrement operator
Examples
========
>>> from sympy.abc import x
>>> from sympy.codegen.cnodes import PostDecrement
>>> from sympy import ccode
>>> ccode(PostDecrement(x))
'(x)--'
"""
nargs = 1
class PreIncrement(Basic):
""" Represents the pre-increment operator
Examples
========
>>> from sympy.abc import x
>>> from sympy.codegen.cnodes import PreIncrement
>>> from sympy import ccode
>>> ccode(PreIncrement(x))
'++(x)'
"""
nargs = 1
class PostIncrement(Basic):
""" Represents the post-increment operator
Examples
========
>>> from sympy.abc import x
>>> from sympy.codegen.cnodes import PostIncrement
>>> from sympy import ccode
>>> ccode(PostIncrement(x))
'(x)++'
"""
nargs = 1
class struct(Node):
""" Represents a struct in C """
__slots__ = _fields = ('name', 'declarations')
defaults = {'name': none}
_construct_name = String
@classmethod
def _construct_declarations(cls, args):
return Tuple(*[Declaration(arg) for arg in args])
class union(struct):
""" Represents a union in C """
__slots__ = ()
PK ]ZZZA�J� sympy/codegen/cutils.pyfrom sympy.printing.c import C99CodePrinter
def render_as_source_file(content, Printer=C99CodePrinter, settings=None):
""" Renders a C source file (with required #include statements) """
printer = Printer(settings or {})
code_str = printer.doprint(content)
includes = '\n'.join(['#include <%s>' % h for h in printer.headers])
return includes + '\n\n' + code_str
PK ]ZZZtp��V V sympy/codegen/cxxnodes.py"""
AST nodes specific to C++.
"""
from sympy.codegen.ast import Attribute, String, Token, Type, none
class using(Token):
""" Represents a 'using' statement in C++ """
__slots__ = _fields = ('type', 'alias')
defaults = {'alias': none}
_construct_type = Type
_construct_alias = String
constexpr = Attribute('constexpr')
PK ]ZZZ�� ��I �I sympy/codegen/fnodes.py"""
AST nodes specific to Fortran.
The functions defined in this module allows the user to express functions such as ``dsign``
as a SymPy function for symbolic manipulation.
"""
from sympy.codegen.ast import (
Attribute, CodeBlock, FunctionCall, Node, none, String,
Token, _mk_Tuple, Variable
)
from sympy.core.basic import Basic
from sympy.core.containers import Tuple
from sympy.core.expr import Expr
from sympy.core.function import Function
from sympy.core.numbers import Float, Integer
from sympy.core.symbol import Str
from sympy.core.sympify import sympify
from sympy.logic import true, false
from sympy.utilities.iterables import iterable
pure = Attribute('pure')
elemental = Attribute('elemental') # (all elemental procedures are also pure)
intent_in = Attribute('intent_in')
intent_out = Attribute('intent_out')
intent_inout = Attribute('intent_inout')
allocatable = Attribute('allocatable')
class Program(Token):
""" Represents a 'program' block in Fortran.
Examples
========
>>> from sympy.codegen.ast import Print
>>> from sympy.codegen.fnodes import Program
>>> prog = Program('myprogram', [Print([42])])
>>> from sympy import fcode
>>> print(fcode(prog, source_format='free'))
program myprogram
print *, 42
end program
"""
__slots__ = _fields = ('name', 'body')
_construct_name = String
_construct_body = staticmethod(lambda body: CodeBlock(*body))
class use_rename(Token):
""" Represents a renaming in a use statement in Fortran.
Examples
========
>>> from sympy.codegen.fnodes import use_rename, use
>>> from sympy import fcode
>>> ren = use_rename("thingy", "convolution2d")
>>> print(fcode(ren, source_format='free'))
thingy => convolution2d
>>> full = use('signallib', only=['snr', ren])
>>> print(fcode(full, source_format='free'))
use signallib, only: snr, thingy => convolution2d
"""
__slots__ = _fields = ('local', 'original')
_construct_local = String
_construct_original = String
def _name(arg):
if hasattr(arg, 'name'):
return arg.name
else:
return String(arg)
class use(Token):
""" Represents a use statement in Fortran.
Examples
========
>>> from sympy.codegen.fnodes import use
>>> from sympy import fcode
>>> fcode(use('signallib'), source_format='free')
'use signallib'
>>> fcode(use('signallib', [('metric', 'snr')]), source_format='free')
'use signallib, metric => snr'
>>> fcode(use('signallib', only=['snr', 'convolution2d']), source_format='free')
'use signallib, only: snr, convolution2d'
"""
__slots__ = _fields = ('namespace', 'rename', 'only')
defaults = {'rename': none, 'only': none}
_construct_namespace = staticmethod(_name)
_construct_rename = staticmethod(lambda args: Tuple(*[arg if isinstance(arg, use_rename) else use_rename(*arg) for arg in args]))
_construct_only = staticmethod(lambda args: Tuple(*[arg if isinstance(arg, use_rename) else _name(arg) for arg in args]))
class Module(Token):
""" Represents a module in Fortran.
Examples
========
>>> from sympy.codegen.fnodes import Module
>>> from sympy import fcode
>>> print(fcode(Module('signallib', ['implicit none'], []), source_format='free'))
module signallib
implicit none
<BLANKLINE>
contains
<BLANKLINE>
<BLANKLINE>
end module
"""
__slots__ = _fields = ('name', 'declarations', 'definitions')
defaults = {'declarations': Tuple()}
_construct_name = String
@classmethod
def _construct_declarations(cls, args):
args = [Str(arg) if isinstance(arg, str) else arg for arg in args]
return CodeBlock(*args)
_construct_definitions = staticmethod(lambda arg: CodeBlock(*arg))
class Subroutine(Node):
""" Represents a subroutine in Fortran.
Examples
========
>>> from sympy import fcode, symbols
>>> from sympy.codegen.ast import Print
>>> from sympy.codegen.fnodes import Subroutine
>>> x, y = symbols('x y', real=True)
>>> sub = Subroutine('mysub', [x, y], [Print([x**2 + y**2, x*y])])
>>> print(fcode(sub, source_format='free', standard=2003))
subroutine mysub(x, y)
real*8 :: x
real*8 :: y
print *, x**2 + y**2, x*y
end subroutine
"""
__slots__ = ('name', 'parameters', 'body')
_fields = __slots__ + Node._fields
_construct_name = String
_construct_parameters = staticmethod(lambda params: Tuple(*map(Variable.deduced, params)))
@classmethod
def _construct_body(cls, itr):
if isinstance(itr, CodeBlock):
return itr
else:
return CodeBlock(*itr)
class SubroutineCall(Token):
""" Represents a call to a subroutine in Fortran.
Examples
========
>>> from sympy.codegen.fnodes import SubroutineCall
>>> from sympy import fcode
>>> fcode(SubroutineCall('mysub', 'x y'.split()))
' call mysub(x, y)'
"""
__slots__ = _fields = ('name', 'subroutine_args')
_construct_name = staticmethod(_name)
_construct_subroutine_args = staticmethod(_mk_Tuple)
class Do(Token):
""" Represents a Do loop in in Fortran.
Examples
========
>>> from sympy import fcode, symbols
>>> from sympy.codegen.ast import aug_assign, Print
>>> from sympy.codegen.fnodes import Do
>>> i, n = symbols('i n', integer=True)
>>> r = symbols('r', real=True)
>>> body = [aug_assign(r, '+', 1/i), Print([i, r])]
>>> do1 = Do(body, i, 1, n)
>>> print(fcode(do1, source_format='free'))
do i = 1, n
r = r + 1d0/i
print *, i, r
end do
>>> do2 = Do(body, i, 1, n, 2)
>>> print(fcode(do2, source_format='free'))
do i = 1, n, 2
r = r + 1d0/i
print *, i, r
end do
"""
__slots__ = _fields = ('body', 'counter', 'first', 'last', 'step', 'concurrent')
defaults = {'step': Integer(1), 'concurrent': false}
_construct_body = staticmethod(lambda body: CodeBlock(*body))
_construct_counter = staticmethod(sympify)
_construct_first = staticmethod(sympify)
_construct_last = staticmethod(sympify)
_construct_step = staticmethod(sympify)
_construct_concurrent = staticmethod(lambda arg: true if arg else false)
class ArrayConstructor(Token):
""" Represents an array constructor.
Examples
========
>>> from sympy import fcode
>>> from sympy.codegen.fnodes import ArrayConstructor
>>> ac = ArrayConstructor([1, 2, 3])
>>> fcode(ac, standard=95, source_format='free')
'(/1, 2, 3/)'
>>> fcode(ac, standard=2003, source_format='free')
'[1, 2, 3]'
"""
__slots__ = _fields = ('elements',)
_construct_elements = staticmethod(_mk_Tuple)
class ImpliedDoLoop(Token):
""" Represents an implied do loop in Fortran.
Examples
========
>>> from sympy import Symbol, fcode
>>> from sympy.codegen.fnodes import ImpliedDoLoop, ArrayConstructor
>>> i = Symbol('i', integer=True)
>>> idl = ImpliedDoLoop(i**3, i, -3, 3, 2) # -27, -1, 1, 27
>>> ac = ArrayConstructor([-28, idl, 28]) # -28, -27, -1, 1, 27, 28
>>> fcode(ac, standard=2003, source_format='free')
'[-28, (i**3, i = -3, 3, 2), 28]'
"""
__slots__ = _fields = ('expr', 'counter', 'first', 'last', 'step')
defaults = {'step': Integer(1)}
_construct_expr = staticmethod(sympify)
_construct_counter = staticmethod(sympify)
_construct_first = staticmethod(sympify)
_construct_last = staticmethod(sympify)
_construct_step = staticmethod(sympify)
class Extent(Basic):
""" Represents a dimension extent.
Examples
========
>>> from sympy.codegen.fnodes import Extent
>>> e = Extent(-3, 3) # -3, -2, -1, 0, 1, 2, 3
>>> from sympy import fcode
>>> fcode(e, source_format='free')
'-3:3'
>>> from sympy.codegen.ast import Variable, real
>>> from sympy.codegen.fnodes import dimension, intent_out
>>> dim = dimension(e, e)
>>> arr = Variable('x', real, attrs=[dim, intent_out])
>>> fcode(arr.as_Declaration(), source_format='free', standard=2003)
'real*8, dimension(-3:3, -3:3), intent(out) :: x'
"""
def __new__(cls, *args):
if len(args) == 2:
low, high = args
return Basic.__new__(cls, sympify(low), sympify(high))
elif len(args) == 0 or (len(args) == 1 and args[0] in (':', None)):
return Basic.__new__(cls) # assumed shape
else:
raise ValueError("Expected 0 or 2 args (or one argument == None or ':')")
def _sympystr(self, printer):
if len(self.args) == 0:
return ':'
return ":".join(str(arg) for arg in self.args)
assumed_extent = Extent() # or Extent(':'), Extent(None)
def dimension(*args):
""" Creates a 'dimension' Attribute with (up to 7) extents.
Examples
========
>>> from sympy import fcode
>>> from sympy.codegen.fnodes import dimension, intent_in
>>> dim = dimension('2', ':') # 2 rows, runtime determined number of columns
>>> from sympy.codegen.ast import Variable, integer
>>> arr = Variable('a', integer, attrs=[dim, intent_in])
>>> fcode(arr.as_Declaration(), source_format='free', standard=2003)
'integer*4, dimension(2, :), intent(in) :: a'
"""
if len(args) > 7:
raise ValueError("Fortran only supports up to 7 dimensional arrays")
parameters = []
for arg in args:
if isinstance(arg, Extent):
parameters.append(arg)
elif isinstance(arg, str):
if arg == ':':
parameters.append(Extent())
else:
parameters.append(String(arg))
elif iterable(arg):
parameters.append(Extent(*arg))
else:
parameters.append(sympify(arg))
if len(args) == 0:
raise ValueError("Need at least one dimension")
return Attribute('dimension', parameters)
assumed_size = dimension('*')
def array(symbol, dim, intent=None, *, attrs=(), value=None, type=None):
""" Convenience function for creating a Variable instance for a Fortran array.
Parameters
==========
symbol : symbol
dim : Attribute or iterable
If dim is an ``Attribute`` it need to have the name 'dimension'. If it is
not an ``Attribute``, then it is passed to :func:`dimension` as ``*dim``
intent : str
One of: 'in', 'out', 'inout' or None
\\*\\*kwargs:
Keyword arguments for ``Variable`` ('type' & 'value')
Examples
========
>>> from sympy import fcode
>>> from sympy.codegen.ast import integer, real
>>> from sympy.codegen.fnodes import array
>>> arr = array('a', '*', 'in', type=integer)
>>> print(fcode(arr.as_Declaration(), source_format='free', standard=2003))
integer*4, dimension(*), intent(in) :: a
>>> x = array('x', [3, ':', ':'], intent='out', type=real)
>>> print(fcode(x.as_Declaration(value=1), source_format='free', standard=2003))
real*8, dimension(3, :, :), intent(out) :: x = 1
"""
if isinstance(dim, Attribute):
if str(dim.name) != 'dimension':
raise ValueError("Got an unexpected Attribute argument as dim: %s" % str(dim))
else:
dim = dimension(*dim)
attrs = list(attrs) + [dim]
if intent is not None:
if intent not in (intent_in, intent_out, intent_inout):
intent = {'in': intent_in, 'out': intent_out, 'inout': intent_inout}[intent]
attrs.append(intent)
if type is None:
return Variable.deduced(symbol, value=value, attrs=attrs)
else:
return Variable(symbol, type, value=value, attrs=attrs)
def _printable(arg):
return String(arg) if isinstance(arg, str) else sympify(arg)
def allocated(array):
""" Creates an AST node for a function call to Fortran's "allocated(...)"
Examples
========
>>> from sympy import fcode
>>> from sympy.codegen.fnodes import allocated
>>> alloc = allocated('x')
>>> fcode(alloc, source_format='free')
'allocated(x)'
"""
return FunctionCall('allocated', [_printable(array)])
def lbound(array, dim=None, kind=None):
""" Creates an AST node for a function call to Fortran's "lbound(...)"
Parameters
==========
array : Symbol or String
dim : expr
kind : expr
Examples
========
>>> from sympy import fcode
>>> from sympy.codegen.fnodes import lbound
>>> lb = lbound('arr', dim=2)
>>> fcode(lb, source_format='free')
'lbound(arr, 2)'
"""
return FunctionCall(
'lbound',
[_printable(array)] +
([_printable(dim)] if dim else []) +
([_printable(kind)] if kind else [])
)
def ubound(array, dim=None, kind=None):
return FunctionCall(
'ubound',
[_printable(array)] +
([_printable(dim)] if dim else []) +
([_printable(kind)] if kind else [])
)
def shape(source, kind=None):
""" Creates an AST node for a function call to Fortran's "shape(...)"
Parameters
==========
source : Symbol or String
kind : expr
Examples
========
>>> from sympy import fcode
>>> from sympy.codegen.fnodes import shape
>>> shp = shape('x')
>>> fcode(shp, source_format='free')
'shape(x)'
"""
return FunctionCall(
'shape',
[_printable(source)] +
([_printable(kind)] if kind else [])
)
def size(array, dim=None, kind=None):
""" Creates an AST node for a function call to Fortran's "size(...)"
Examples
========
>>> from sympy import fcode, Symbol
>>> from sympy.codegen.ast import FunctionDefinition, real, Return
>>> from sympy.codegen.fnodes import array, sum_, size
>>> a = Symbol('a', real=True)
>>> body = [Return((sum_(a**2)/size(a))**.5)]
>>> arr = array(a, dim=[':'], intent='in')
>>> fd = FunctionDefinition(real, 'rms', [arr], body)
>>> print(fcode(fd, source_format='free', standard=2003))
real*8 function rms(a)
real*8, dimension(:), intent(in) :: a
rms = sqrt(sum(a**2)*1d0/size(a))
end function
"""
return FunctionCall(
'size',
[_printable(array)] +
([_printable(dim)] if dim else []) +
([_printable(kind)] if kind else [])
)
def reshape(source, shape, pad=None, order=None):
""" Creates an AST node for a function call to Fortran's "reshape(...)"
Parameters
==========
source : Symbol or String
shape : ArrayExpr
"""
return FunctionCall(
'reshape',
[_printable(source), _printable(shape)] +
([_printable(pad)] if pad else []) +
([_printable(order)] if pad else [])
)
def bind_C(name=None):
""" Creates an Attribute ``bind_C`` with a name.
Parameters
==========
name : str
Examples
========
>>> from sympy import fcode, Symbol
>>> from sympy.codegen.ast import FunctionDefinition, real, Return
>>> from sympy.codegen.fnodes import array, sum_, bind_C
>>> a = Symbol('a', real=True)
>>> s = Symbol('s', integer=True)
>>> arr = array(a, dim=[s], intent='in')
>>> body = [Return((sum_(a**2)/s)**.5)]
>>> fd = FunctionDefinition(real, 'rms', [arr, s], body, attrs=[bind_C('rms')])
>>> print(fcode(fd, source_format='free', standard=2003))
real*8 function rms(a, s) bind(C, name="rms")
real*8, dimension(s), intent(in) :: a
integer*4 :: s
rms = sqrt(sum(a**2)/s)
end function
"""
return Attribute('bind_C', [String(name)] if name else [])
class GoTo(Token):
""" Represents a goto statement in Fortran
Examples
========
>>> from sympy.codegen.fnodes import GoTo
>>> go = GoTo([10, 20, 30], 'i')
>>> from sympy import fcode
>>> fcode(go, source_format='free')
'go to (10, 20, 30), i'
"""
__slots__ = _fields = ('labels', 'expr')
defaults = {'expr': none}
_construct_labels = staticmethod(_mk_Tuple)
_construct_expr = staticmethod(sympify)
class FortranReturn(Token):
""" AST node explicitly mapped to a fortran "return".
Explanation
===========
Because a return statement in fortran is different from C, and
in order to aid reuse of our codegen ASTs the ordinary
``.codegen.ast.Return`` is interpreted as assignment to
the result variable of the function. If one for some reason needs
to generate a fortran RETURN statement, this node should be used.
Examples
========
>>> from sympy.codegen.fnodes import FortranReturn
>>> from sympy import fcode
>>> fcode(FortranReturn('x'))
' return x'
"""
__slots__ = _fields = ('return_value',)
defaults = {'return_value': none}
_construct_return_value = staticmethod(sympify)
class FFunction(Function):
_required_standard = 77
def _fcode(self, printer):
name = self.__class__.__name__
if printer._settings['standard'] < self._required_standard:
raise NotImplementedError("%s requires Fortran %d or newer" %
(name, self._required_standard))
return '{}({})'.format(name, ', '.join(map(printer._print, self.args)))
class F95Function(FFunction):
_required_standard = 95
class isign(FFunction):
""" Fortran sign intrinsic for integer arguments. """
nargs = 2
class dsign(FFunction):
""" Fortran sign intrinsic for double precision arguments. """
nargs = 2
class cmplx(FFunction):
""" Fortran complex conversion function. """
nargs = 2 # may be extended to (2, 3) at a later point
class kind(FFunction):
""" Fortran kind function. """
nargs = 1
class merge(F95Function):
""" Fortran merge function """
nargs = 3
class _literal(Float):
_token = None # type: str
_decimals = None # type: int
def _fcode(self, printer, *args, **kwargs):
mantissa, sgnd_ex = ('%.{}e'.format(self._decimals) % self).split('e')
mantissa = mantissa.strip('0').rstrip('.')
ex_sgn, ex_num = sgnd_ex[0], sgnd_ex[1:].lstrip('0')
ex_sgn = '' if ex_sgn == '+' else ex_sgn
return (mantissa or '0') + self._token + ex_sgn + (ex_num or '0')
class literal_sp(_literal):
""" Fortran single precision real literal """
_token = 'e'
_decimals = 9
class literal_dp(_literal):
""" Fortran double precision real literal """
_token = 'd'
_decimals = 17
class sum_(Token, Expr):
__slots__ = _fields = ('array', 'dim', 'mask')
defaults = {'dim': none, 'mask': none}
_construct_array = staticmethod(sympify)
_construct_dim = staticmethod(sympify)
class product_(Token, Expr):
__slots__ = _fields = ('array', 'dim', 'mask')
defaults = {'dim': none, 'mask': none}
_construct_array = staticmethod(sympify)
_construct_dim = staticmethod(sympify)
PK ]ZZZ]k� sympy/codegen/futils.pyfrom itertools import chain
from sympy.codegen.fnodes import Module
from sympy.core.symbol import Dummy
from sympy.printing.fortran import FCodePrinter
""" This module collects utilities for rendering Fortran code. """
def render_as_module(definitions, name, declarations=(), printer_settings=None):
""" Creates a ``Module`` instance and renders it as a string.
This generates Fortran source code for a module with the correct ``use`` statements.
Parameters
==========
definitions : iterable
Passed to :class:`sympy.codegen.fnodes.Module`.
name : str
Passed to :class:`sympy.codegen.fnodes.Module`.
declarations : iterable
Passed to :class:`sympy.codegen.fnodes.Module`. It will be extended with
use statements, 'implicit none' and public list generated from ``definitions``.
printer_settings : dict
Passed to ``FCodePrinter`` (default: ``{'standard': 2003, 'source_format': 'free'}``).
"""
printer_settings = printer_settings or {'standard': 2003, 'source_format': 'free'}
printer = FCodePrinter(printer_settings)
dummy = Dummy()
if isinstance(definitions, Module):
raise ValueError("This function expects to construct a module on its own.")
mod = Module(name, chain(declarations, [dummy]), definitions)
fstr = printer.doprint(mod)
module_use_str = ' %s\n' % ' \n'.join(['use %s, only: %s' % (k, ', '.join(v)) for
k, v in printer.module_uses.items()])
module_use_str += ' implicit none\n'
module_use_str += ' private\n'
module_use_str += ' public %s\n' % ', '.join([str(node.name) for node in definitions if getattr(node, 'name', None)])
return fstr.replace(printer.doprint(dummy), module_use_str)
PK ]ZZZk�3�� � sympy/codegen/matrix_nodes.py"""
Additional AST nodes for operations on matrices. The nodes in this module
are meant to represent optimization of matrix expressions within codegen's
target languages that cannot be represented by SymPy expressions.
As an example, we can use :meth:`sympy.codegen.rewriting.optimize` and the
``matin_opt`` optimization provided in :mod:`sympy.codegen.rewriting` to
transform matrix multiplication under certain assumptions:
>>> from sympy import symbols, MatrixSymbol
>>> n = symbols('n', integer=True)
>>> A = MatrixSymbol('A', n, n)
>>> x = MatrixSymbol('x', n, 1)
>>> expr = A**(-1) * x
>>> from sympy import assuming, Q
>>> from sympy.codegen.rewriting import matinv_opt, optimize
>>> with assuming(Q.fullrank(A)):
... optimize(expr, [matinv_opt])
MatrixSolve(A, vector=x)
"""
from .ast import Token
from sympy.matrices import MatrixExpr
from sympy.core.sympify import sympify
class MatrixSolve(Token, MatrixExpr):
"""Represents an operation to solve a linear matrix equation.
Parameters
==========
matrix : MatrixSymbol
Matrix representing the coefficients of variables in the linear
equation. This matrix must be square and full-rank (i.e. all columns must
be linearly independent) for the solving operation to be valid.
vector : MatrixSymbol
One-column matrix representing the solutions to the equations
represented in ``matrix``.
Examples
========
>>> from sympy import symbols, MatrixSymbol
>>> from sympy.codegen.matrix_nodes import MatrixSolve
>>> n = symbols('n', integer=True)
>>> A = MatrixSymbol('A', n, n)
>>> x = MatrixSymbol('x', n, 1)
>>> from sympy.printing.numpy import NumPyPrinter
>>> NumPyPrinter().doprint(MatrixSolve(A, x))
'numpy.linalg.solve(A, x)'
>>> from sympy import octave_code
>>> octave_code(MatrixSolve(A, x))
'A \\\\ x'
"""
__slots__ = _fields = ('matrix', 'vector')
_construct_matrix = staticmethod(sympify)
_construct_vector = staticmethod(sympify)
@property
def shape(self):
return self.vector.shape
def _eval_derivative(self, x):
A, b = self.matrix, self.vector
return MatrixSolve(A, b.diff(x) - A.diff(x) * MatrixSolve(A, b))
PK ]ZZZ��>A A sympy/codegen/numpy_nodes.pyfrom sympy.core.function import Add, ArgumentIndexError, Function
from sympy.core.power import Pow
from sympy.core.singleton import S
from sympy.core.sorting import default_sort_key
from sympy.functions.elementary.exponential import exp, log
def _logaddexp(x1, x2, *, evaluate=True):
return log(Add(exp(x1, evaluate=evaluate), exp(x2, evaluate=evaluate), evaluate=evaluate))
_two = S.One*2
_ln2 = log(_two)
def _lb(x, *, evaluate=True):
return log(x, evaluate=evaluate)/_ln2
def _exp2(x, *, evaluate=True):
return Pow(_two, x, evaluate=evaluate)
def _logaddexp2(x1, x2, *, evaluate=True):
return _lb(Add(_exp2(x1, evaluate=evaluate),
_exp2(x2, evaluate=evaluate), evaluate=evaluate))
class logaddexp(Function):
""" Logarithm of the sum of exponentiations of the inputs.
Helper class for use with e.g. numpy.logaddexp
See Also
========
https://numpy.org/doc/stable/reference/generated/numpy.logaddexp.html
"""
nargs = 2
def __new__(cls, *args):
return Function.__new__(cls, *sorted(args, key=default_sort_key))
def fdiff(self, argindex=1):
"""
Returns the first derivative of this function.
"""
if argindex == 1:
wrt, other = self.args
elif argindex == 2:
other, wrt = self.args
else:
raise ArgumentIndexError(self, argindex)
return S.One/(S.One + exp(other-wrt))
def _eval_rewrite_as_log(self, x1, x2, **kwargs):
return _logaddexp(x1, x2)
def _eval_evalf(self, *args, **kwargs):
return self.rewrite(log).evalf(*args, **kwargs)
def _eval_simplify(self, *args, **kwargs):
a, b = (x.simplify(**kwargs) for x in self.args)
candidate = _logaddexp(a, b)
if candidate != _logaddexp(a, b, evaluate=False):
return candidate
else:
return logaddexp(a, b)
class logaddexp2(Function):
""" Logarithm of the sum of exponentiations of the inputs in base-2.
Helper class for use with e.g. numpy.logaddexp2
See Also
========
https://numpy.org/doc/stable/reference/generated/numpy.logaddexp2.html
"""
nargs = 2
def __new__(cls, *args):
return Function.__new__(cls, *sorted(args, key=default_sort_key))
def fdiff(self, argindex=1):
"""
Returns the first derivative of this function.
"""
if argindex == 1:
wrt, other = self.args
elif argindex == 2:
other, wrt = self.args
else:
raise ArgumentIndexError(self, argindex)
return S.One/(S.One + _exp2(other-wrt))
def _eval_rewrite_as_log(self, x1, x2, **kwargs):
return _logaddexp2(x1, x2)
def _eval_evalf(self, *args, **kwargs):
return self.rewrite(log).evalf(*args, **kwargs)
def _eval_simplify(self, *args, **kwargs):
a, b = (x.simplify(**kwargs).factor() for x in self.args)
candidate = _logaddexp2(a, b)
if candidate != _logaddexp2(a, b, evaluate=False):
return candidate
else:
return logaddexp2(a, b)
PK ]ZZZ@�/�� � sympy/codegen/pynodes.pyfrom .abstract_nodes import List as AbstractList
from .ast import Token
class List(AbstractList):
pass
class NumExprEvaluate(Token):
"""represents a call to :class:`numexpr`s :func:`evaluate`"""
__slots__ = _fields = ('expr',)
PK ]ZZZ8�F F sympy/codegen/pyutils.pyfrom sympy.printing.pycode import PythonCodePrinter
""" This module collects utilities for rendering Python code. """
def render_as_module(content, standard='python3'):
"""Renders Python code as a module (with the required imports).
Parameters
==========
standard :
See the parameter ``standard`` in
:meth:`sympy.printing.pycode.pycode`
"""
printer = PythonCodePrinter({'standard':standard})
pystr = printer.doprint(content)
if printer._settings['fully_qualified_modules']:
module_imports_str = '\n'.join('import %s' % k for k in printer.module_imports)
else:
module_imports_str = '\n'.join(['from %s import %s' % (k, ', '.join(v)) for
k, v in printer.module_imports.items()])
return module_imports_str + '\n\n' + pystr
PK ]ZZZSHWA- A- sympy/codegen/rewriting.py"""
Classes and functions useful for rewriting expressions for optimized code
generation. Some languages (or standards thereof), e.g. C99, offer specialized
math functions for better performance and/or precision.
Using the ``optimize`` function in this module, together with a collection of
rules (represented as instances of ``Optimization``), one can rewrite the
expressions for this purpose::
>>> from sympy import Symbol, exp, log
>>> from sympy.codegen.rewriting import optimize, optims_c99
>>> x = Symbol('x')
>>> optimize(3*exp(2*x) - 3, optims_c99)
3*expm1(2*x)
>>> optimize(exp(2*x) - 1 - exp(-33), optims_c99)
expm1(2*x) - exp(-33)
>>> optimize(log(3*x + 3), optims_c99)
log1p(x) + log(3)
>>> optimize(log(2*x + 3), optims_c99)
log(2*x + 3)
The ``optims_c99`` imported above is tuple containing the following instances
(which may be imported from ``sympy.codegen.rewriting``):
- ``expm1_opt``
- ``log1p_opt``
- ``exp2_opt``
- ``log2_opt``
- ``log2const_opt``
"""
from sympy.core.function import expand_log
from sympy.core.singleton import S
from sympy.core.symbol import Wild
from sympy.functions.elementary.complexes import sign
from sympy.functions.elementary.exponential import (exp, log)
from sympy.functions.elementary.miscellaneous import (Max, Min)
from sympy.functions.elementary.trigonometric import (cos, sin, sinc)
from sympy.assumptions import Q, ask
from sympy.codegen.cfunctions import log1p, log2, exp2, expm1
from sympy.codegen.matrix_nodes import MatrixSolve
from sympy.core.expr import UnevaluatedExpr
from sympy.core.power import Pow
from sympy.codegen.numpy_nodes import logaddexp, logaddexp2
from sympy.codegen.scipy_nodes import cosm1, powm1
from sympy.core.mul import Mul
from sympy.matrices.expressions.matexpr import MatrixSymbol
from sympy.utilities.iterables import sift
class Optimization:
""" Abstract base class for rewriting optimization.
Subclasses should implement ``__call__`` taking an expression
as argument.
Parameters
==========
cost_function : callable returning number
priority : number
"""
def __init__(self, cost_function=None, priority=1):
self.cost_function = cost_function
self.priority=priority
def cheapest(self, *args):
return min(args, key=self.cost_function)
class ReplaceOptim(Optimization):
""" Rewriting optimization calling replace on expressions.
Explanation
===========
The instance can be used as a function on expressions for which
it will apply the ``replace`` method (see
:meth:`sympy.core.basic.Basic.replace`).
Parameters
==========
query :
First argument passed to replace.
value :
Second argument passed to replace.
Examples
========
>>> from sympy import Symbol
>>> from sympy.codegen.rewriting import ReplaceOptim
>>> from sympy.codegen.cfunctions import exp2
>>> x = Symbol('x')
>>> exp2_opt = ReplaceOptim(lambda p: p.is_Pow and p.base == 2,
... lambda p: exp2(p.exp))
>>> exp2_opt(2**x)
exp2(x)
"""
def __init__(self, query, value, **kwargs):
super().__init__(**kwargs)
self.query = query
self.value = value
def __call__(self, expr):
return expr.replace(self.query, self.value)
def optimize(expr, optimizations):
""" Apply optimizations to an expression.
Parameters
==========
expr : expression
optimizations : iterable of ``Optimization`` instances
The optimizations will be sorted with respect to ``priority`` (highest first).
Examples
========
>>> from sympy import log, Symbol
>>> from sympy.codegen.rewriting import optims_c99, optimize
>>> x = Symbol('x')
>>> optimize(log(x+3)/log(2) + log(x**2 + 1), optims_c99)
log1p(x**2) + log2(x + 3)
"""
for optim in sorted(optimizations, key=lambda opt: opt.priority, reverse=True):
new_expr = optim(expr)
if optim.cost_function is None:
expr = new_expr
else:
expr = optim.cheapest(expr, new_expr)
return expr
exp2_opt = ReplaceOptim(
lambda p: p.is_Pow and p.base == 2,
lambda p: exp2(p.exp)
)
_d = Wild('d', properties=[lambda x: x.is_Dummy])
_u = Wild('u', properties=[lambda x: not x.is_number and not x.is_Add])
_v = Wild('v')
_w = Wild('w')
_n = Wild('n', properties=[lambda x: x.is_number])
sinc_opt1 = ReplaceOptim(
sin(_w)/_w, sinc(_w)
)
sinc_opt2 = ReplaceOptim(
sin(_n*_w)/_w, _n*sinc(_n*_w)
)
sinc_opts = (sinc_opt1, sinc_opt2)
log2_opt = ReplaceOptim(_v*log(_w)/log(2), _v*log2(_w), cost_function=lambda expr: expr.count(
lambda e: ( # division & eval of transcendentals are expensive floating point operations...
e.is_Pow and e.exp.is_negative # division
or (isinstance(e, (log, log2)) and not e.args[0].is_number)) # transcendental
)
)
log2const_opt = ReplaceOptim(log(2)*log2(_w), log(_w))
logsumexp_2terms_opt = ReplaceOptim(
lambda l: (isinstance(l, log)
and l.args[0].is_Add
and len(l.args[0].args) == 2
and all(isinstance(t, exp) for t in l.args[0].args)),
lambda l: (
Max(*[e.args[0] for e in l.args[0].args]) +
log1p(exp(Min(*[e.args[0] for e in l.args[0].args])))
)
)
class FuncMinusOneOptim(ReplaceOptim):
"""Specialization of ReplaceOptim for functions evaluating "f(x) - 1".
Explanation
===========
Numerical functions which go toward one as x go toward zero is often best
implemented by a dedicated function in order to avoid catastrophic
cancellation. One such example is ``expm1(x)`` in the C standard library
which evaluates ``exp(x) - 1``. Such functions preserves many more
significant digits when its argument is much smaller than one, compared
to subtracting one afterwards.
Parameters
==========
func :
The function which is subtracted by one.
func_m_1 :
The specialized function evaluating ``func(x) - 1``.
opportunistic : bool
When ``True``, apply the transformation as long as the magnitude of the
remaining number terms decreases. When ``False``, only apply the
transformation if it completely eliminates the number term.
Examples
========
>>> from sympy import symbols, exp
>>> from sympy.codegen.rewriting import FuncMinusOneOptim
>>> from sympy.codegen.cfunctions import expm1
>>> x, y = symbols('x y')
>>> expm1_opt = FuncMinusOneOptim(exp, expm1)
>>> expm1_opt(exp(x) + 2*exp(5*y) - 3)
expm1(x) + 2*expm1(5*y)
"""
def __init__(self, func, func_m_1, opportunistic=True):
weight = 10 # <-- this is an arbitrary number (heuristic)
super().__init__(lambda e: e.is_Add, self.replace_in_Add,
cost_function=lambda expr: expr.count_ops() - weight*expr.count(func_m_1))
self.func = func
self.func_m_1 = func_m_1
self.opportunistic = opportunistic
def _group_Add_terms(self, add):
numbers, non_num = sift(add.args, lambda arg: arg.is_number, binary=True)
numsum = sum(numbers)
terms_with_func, other = sift(non_num, lambda arg: arg.has(self.func), binary=True)
return numsum, terms_with_func, other
def replace_in_Add(self, e):
""" passed as second argument to Basic.replace(...) """
numsum, terms_with_func, other_non_num_terms = self._group_Add_terms(e)
if numsum == 0:
return e
substituted, untouched = [], []
for with_func in terms_with_func:
if with_func.is_Mul:
func, coeff = sift(with_func.args, lambda arg: arg.func == self.func, binary=True)
if len(func) == 1 and len(coeff) == 1:
func, coeff = func[0], coeff[0]
else:
coeff = None
elif with_func.func == self.func:
func, coeff = with_func, S.One
else:
coeff = None
if coeff is not None and coeff.is_number and sign(coeff) == -sign(numsum):
if self.opportunistic:
do_substitute = abs(coeff+numsum) < abs(numsum)
else:
do_substitute = coeff+numsum == 0
if do_substitute: # advantageous substitution
numsum += coeff
substituted.append(coeff*self.func_m_1(*func.args))
continue
untouched.append(with_func)
return e.func(numsum, *substituted, *untouched, *other_non_num_terms)
def __call__(self, expr):
alt1 = super().__call__(expr)
alt2 = super().__call__(expr.factor())
return self.cheapest(alt1, alt2)
expm1_opt = FuncMinusOneOptim(exp, expm1)
cosm1_opt = FuncMinusOneOptim(cos, cosm1)
powm1_opt = FuncMinusOneOptim(Pow, powm1)
log1p_opt = ReplaceOptim(
lambda e: isinstance(e, log),
lambda l: expand_log(l.replace(
log, lambda arg: log(arg.factor())
)).replace(log(_u+1), log1p(_u))
)
def create_expand_pow_optimization(limit, *, base_req=lambda b: b.is_symbol):
""" Creates an instance of :class:`ReplaceOptim` for expanding ``Pow``.
Explanation
===========
The requirements for expansions are that the base needs to be a symbol
and the exponent needs to be an Integer (and be less than or equal to
``limit``).
Parameters
==========
limit : int
The highest power which is expanded into multiplication.
base_req : function returning bool
Requirement on base for expansion to happen, default is to return
the ``is_symbol`` attribute of the base.
Examples
========
>>> from sympy import Symbol, sin
>>> from sympy.codegen.rewriting import create_expand_pow_optimization
>>> x = Symbol('x')
>>> expand_opt = create_expand_pow_optimization(3)
>>> expand_opt(x**5 + x**3)
x**5 + x*x*x
>>> expand_opt(x**5 + x**3 + sin(x)**3)
x**5 + sin(x)**3 + x*x*x
>>> opt2 = create_expand_pow_optimization(3, base_req=lambda b: not b.is_Function)
>>> opt2((x+1)**2 + sin(x)**2)
sin(x)**2 + (x + 1)*(x + 1)
"""
return ReplaceOptim(
lambda e: e.is_Pow and base_req(e.base) and e.exp.is_Integer and abs(e.exp) <= limit,
lambda p: (
UnevaluatedExpr(Mul(*([p.base]*+p.exp), evaluate=False)) if p.exp > 0 else
1/UnevaluatedExpr(Mul(*([p.base]*-p.exp), evaluate=False))
))
# Optimization procedures for turning A**(-1) * x into MatrixSolve(A, x)
def _matinv_predicate(expr):
# TODO: We should be able to support more than 2 elements
if expr.is_MatMul and len(expr.args) == 2:
left, right = expr.args
if left.is_Inverse and right.shape[1] == 1:
inv_arg = left.arg
if isinstance(inv_arg, MatrixSymbol):
return bool(ask(Q.fullrank(left.arg)))
return False
def _matinv_transform(expr):
left, right = expr.args
inv_arg = left.arg
return MatrixSolve(inv_arg, right)
matinv_opt = ReplaceOptim(_matinv_predicate, _matinv_transform)
logaddexp_opt = ReplaceOptim(log(exp(_v)+exp(_w)), logaddexp(_v, _w))
logaddexp2_opt = ReplaceOptim(log(Pow(2, _v)+Pow(2, _w)), logaddexp2(_v, _w)*log(2))
# Collections of optimizations:
optims_c99 = (expm1_opt, log1p_opt, exp2_opt, log2_opt, log2const_opt)
optims_numpy = optims_c99 + (logaddexp_opt, logaddexp2_opt,) + sinc_opts
optims_scipy = (cosm1_opt, powm1_opt)
PK ]ZZZ�L�k� � sympy/codegen/scipy_nodes.pyfrom sympy.core.function import Add, ArgumentIndexError, Function
from sympy.core.power import Pow
from sympy.core.singleton import S
from sympy.functions.elementary.exponential import log
from sympy.functions.elementary.trigonometric import cos, sin
def _cosm1(x, *, evaluate=True):
return Add(cos(x, evaluate=evaluate), -S.One, evaluate=evaluate)
class cosm1(Function):
""" Minus one plus cosine of x, i.e. cos(x) - 1. For use when x is close to zero.
Helper class for use with e.g. scipy.special.cosm1
See: https://docs.scipy.org/doc/scipy/reference/generated/scipy.special.cosm1.html
"""
nargs = 1
def fdiff(self, argindex=1):
"""
Returns the first derivative of this function.
"""
if argindex == 1:
return -sin(*self.args)
else:
raise ArgumentIndexError(self, argindex)
def _eval_rewrite_as_cos(self, x, **kwargs):
return _cosm1(x)
def _eval_evalf(self, *args, **kwargs):
return self.rewrite(cos).evalf(*args, **kwargs)
def _eval_simplify(self, **kwargs):
x, = self.args
candidate = _cosm1(x.simplify(**kwargs))
if candidate != _cosm1(x, evaluate=False):
return candidate
else:
return cosm1(x)
def _powm1(x, y, *, evaluate=True):
return Add(Pow(x, y, evaluate=evaluate), -S.One, evaluate=evaluate)
class powm1(Function):
""" Minus one plus x to the power of y, i.e. x**y - 1. For use when x is close to one or y is close to zero.
Helper class for use with e.g. scipy.special.powm1
See: https://docs.scipy.org/doc/scipy/reference/generated/scipy.special.powm1.html
"""
nargs = 2
def fdiff(self, argindex=1):
"""
Returns the first derivative of this function.
"""
if argindex == 1:
return Pow(self.args[0], self.args[1])*self.args[1]/self.args[0]
elif argindex == 2:
return log(self.args[0])*Pow(*self.args)
else:
raise ArgumentIndexError(self, argindex)
def _eval_rewrite_as_Pow(self, x, y, **kwargs):
return _powm1(x, y)
def _eval_evalf(self, *args, **kwargs):
return self.rewrite(Pow).evalf(*args, **kwargs)
def _eval_simplify(self, **kwargs):
x, y = self.args
candidate = _powm1(x.simplify(**kwargs), y.simplify(**kwargs))
if candidate != _powm1(x, y, evaluate=False):
return candidate
else:
return powm1(x, y)
PK ]ZZZ�c��� � sympy/combinatorics/__init__.pyfrom sympy.combinatorics.permutations import Permutation, Cycle
from sympy.combinatorics.prufer import Prufer
from sympy.combinatorics.generators import cyclic, alternating, symmetric, dihedral
from sympy.combinatorics.subsets import Subset
from sympy.combinatorics.partitions import (Partition, IntegerPartition,
RGS_rank, RGS_unrank, RGS_enum)
from sympy.combinatorics.polyhedron import (Polyhedron, tetrahedron, cube,
octahedron, dodecahedron, icosahedron)
from sympy.combinatorics.perm_groups import PermutationGroup, Coset, SymmetricPermutationGroup
from sympy.combinatorics.group_constructs import DirectProduct
from sympy.combinatorics.graycode import GrayCode
from sympy.combinatorics.named_groups import (SymmetricGroup, DihedralGroup,
CyclicGroup, AlternatingGroup, AbelianGroup, RubikGroup)
from sympy.combinatorics.pc_groups import PolycyclicGroup, Collector
from sympy.combinatorics.free_groups import free_group
__all__ = [
'Permutation', 'Cycle',
'Prufer',
'cyclic', 'alternating', 'symmetric', 'dihedral',
'Subset',
'Partition', 'IntegerPartition', 'RGS_rank', 'RGS_unrank', 'RGS_enum',
'Polyhedron', 'tetrahedron', 'cube', 'octahedron', 'dodecahedron',
'icosahedron',
'PermutationGroup', 'Coset', 'SymmetricPermutationGroup',
'DirectProduct',
'GrayCode',
'SymmetricGroup', 'DihedralGroup', 'CyclicGroup', 'AlternatingGroup',
'AbelianGroup', 'RubikGroup',
'PolycyclicGroup', 'Collector',
'free_group',
]
PK ]ZZZ͝���� �� " sympy/combinatorics/coset_table.pyfrom sympy.combinatorics.free_groups import free_group
from sympy.printing.defaults import DefaultPrinting
from itertools import chain, product
from bisect import bisect_left
###############################################################################
# COSET TABLE #
###############################################################################
class CosetTable(DefaultPrinting):
# coset_table: Mathematically a coset table
# represented using a list of lists
# alpha: Mathematically a coset (precisely, a live coset)
# represented by an integer between i with 1 <= i <= n
# alpha in c
# x: Mathematically an element of "A" (set of generators and
# their inverses), represented using "FpGroupElement"
# fp_grp: Finitely Presented Group with < X|R > as presentation.
# H: subgroup of fp_grp.
# NOTE: We start with H as being only a list of words in generators
# of "fp_grp". Since `.subgroup` method has not been implemented.
r"""
Properties
==========
[1] `0 \in \Omega` and `\tau(1) = \epsilon`
[2] `\alpha^x = \beta \Leftrightarrow \beta^{x^{-1}} = \alpha`
[3] If `\alpha^x = \beta`, then `H \tau(\alpha)x = H \tau(\beta)`
[4] `\forall \alpha \in \Omega, 1^{\tau(\alpha)} = \alpha`
References
==========
.. [1] Holt, D., Eick, B., O'Brien, E.
"Handbook of Computational Group Theory"
.. [2] John J. Cannon; Lucien A. Dimino; George Havas; Jane M. Watson
Mathematics of Computation, Vol. 27, No. 123. (Jul., 1973), pp. 463-490.
"Implementation and Analysis of the Todd-Coxeter Algorithm"
"""
# default limit for the number of cosets allowed in a
# coset enumeration.
coset_table_max_limit = 4096000
# limit for the current instance
coset_table_limit = None
# maximum size of deduction stack above or equal to
# which it is emptied
max_stack_size = 100
def __init__(self, fp_grp, subgroup, max_cosets=None):
if not max_cosets:
max_cosets = CosetTable.coset_table_max_limit
self.fp_group = fp_grp
self.subgroup = subgroup
self.coset_table_limit = max_cosets
# "p" is setup independent of Omega and n
self.p = [0]
# a list of the form `[gen_1, gen_1^{-1}, ... , gen_k, gen_k^{-1}]`
self.A = list(chain.from_iterable((gen, gen**-1) \
for gen in self.fp_group.generators))
#P[alpha, x] Only defined when alpha^x is defined.
self.P = [[None]*len(self.A)]
# the mathematical coset table which is a list of lists
self.table = [[None]*len(self.A)]
self.A_dict = {x: self.A.index(x) for x in self.A}
self.A_dict_inv = {}
for x, index in self.A_dict.items():
if index % 2 == 0:
self.A_dict_inv[x] = self.A_dict[x] + 1
else:
self.A_dict_inv[x] = self.A_dict[x] - 1
# used in the coset-table based method of coset enumeration. Each of
# the element is called a "deduction" which is the form (alpha, x) whenever
# a value is assigned to alpha^x during a definition or "deduction process"
self.deduction_stack = []
# Attributes for modified methods.
H = self.subgroup
self._grp = free_group(', ' .join(["a_%d" % i for i in range(len(H))]))[0]
self.P = [[None]*len(self.A)]
self.p_p = {}
@property
def omega(self):
"""Set of live cosets. """
return [coset for coset in range(len(self.p)) if self.p[coset] == coset]
def copy(self):
"""
Return a shallow copy of Coset Table instance ``self``.
"""
self_copy = self.__class__(self.fp_group, self.subgroup)
self_copy.table = [list(perm_rep) for perm_rep in self.table]
self_copy.p = list(self.p)
self_copy.deduction_stack = list(self.deduction_stack)
return self_copy
def __str__(self):
return "Coset Table on %s with %s as subgroup generators" \
% (self.fp_group, self.subgroup)
__repr__ = __str__
@property
def n(self):
"""The number `n` represents the length of the sublist containing the
live cosets.
"""
if not self.table:
return 0
return max(self.omega) + 1
# Pg. 152 [1]
def is_complete(self):
r"""
The coset table is called complete if it has no undefined entries
on the live cosets; that is, `\alpha^x` is defined for all
`\alpha \in \Omega` and `x \in A`.
"""
return not any(None in self.table[coset] for coset in self.omega)
# Pg. 153 [1]
def define(self, alpha, x, modified=False):
r"""
This routine is used in the relator-based strategy of Todd-Coxeter
algorithm if some `\alpha^x` is undefined. We check whether there is
space available for defining a new coset. If there is enough space
then we remedy this by adjoining a new coset `\beta` to `\Omega`
(i.e to set of live cosets) and put that equal to `\alpha^x`, then
make an assignment satisfying Property[1]. If there is not enough space
then we halt the Coset Table creation. The maximum amount of space that
can be used by Coset Table can be manipulated using the class variable
``CosetTable.coset_table_max_limit``.
See Also
========
define_c
"""
A = self.A
table = self.table
len_table = len(table)
if len_table >= self.coset_table_limit:
# abort the further generation of cosets
raise ValueError("the coset enumeration has defined more than "
"%s cosets. Try with a greater value max number of cosets "
% self.coset_table_limit)
table.append([None]*len(A))
self.P.append([None]*len(self.A))
# beta is the new coset generated
beta = len_table
self.p.append(beta)
table[alpha][self.A_dict[x]] = beta
table[beta][self.A_dict_inv[x]] = alpha
# P[alpha][x] = epsilon, P[beta][x**-1] = epsilon
if modified:
self.P[alpha][self.A_dict[x]] = self._grp.identity
self.P[beta][self.A_dict_inv[x]] = self._grp.identity
self.p_p[beta] = self._grp.identity
def define_c(self, alpha, x):
r"""
A variation of ``define`` routine, described on Pg. 165 [1], used in
the coset table-based strategy of Todd-Coxeter algorithm. It differs
from ``define`` routine in that for each definition it also adds the
tuple `(\alpha, x)` to the deduction stack.
See Also
========
define
"""
A = self.A
table = self.table
len_table = len(table)
if len_table >= self.coset_table_limit:
# abort the further generation of cosets
raise ValueError("the coset enumeration has defined more than "
"%s cosets. Try with a greater value max number of cosets "
% self.coset_table_limit)
table.append([None]*len(A))
# beta is the new coset generated
beta = len_table
self.p.append(beta)
table[alpha][self.A_dict[x]] = beta
table[beta][self.A_dict_inv[x]] = alpha
# append to deduction stack
self.deduction_stack.append((alpha, x))
def scan_c(self, alpha, word):
"""
A variation of ``scan`` routine, described on pg. 165 of [1], which
puts at tuple, whenever a deduction occurs, to deduction stack.
See Also
========
scan, scan_check, scan_and_fill, scan_and_fill_c
"""
# alpha is an integer representing a "coset"
# since scanning can be in two cases
# 1. for alpha=0 and w in Y (i.e generating set of H)
# 2. alpha in Omega (set of live cosets), w in R (relators)
A_dict = self.A_dict
A_dict_inv = self.A_dict_inv
table = self.table
f = alpha
i = 0
r = len(word)
b = alpha
j = r - 1
# list of union of generators and their inverses
while i <= j and table[f][A_dict[word[i]]] is not None:
f = table[f][A_dict[word[i]]]
i += 1
if i > j:
if f != b:
self.coincidence_c(f, b)
return
while j >= i and table[b][A_dict_inv[word[j]]] is not None:
b = table[b][A_dict_inv[word[j]]]
j -= 1
if j < i:
# we have an incorrect completed scan with coincidence f ~ b
# run the "coincidence" routine
self.coincidence_c(f, b)
elif j == i:
# deduction process
table[f][A_dict[word[i]]] = b
table[b][A_dict_inv[word[i]]] = f
self.deduction_stack.append((f, word[i]))
# otherwise scan is incomplete and yields no information
# alpha, beta coincide, i.e. alpha, beta represent the pair of cosets where
# coincidence occurs
def coincidence_c(self, alpha, beta):
"""
A variation of ``coincidence`` routine used in the coset-table based
method of coset enumeration. The only difference being on addition of
a new coset in coset table(i.e new coset introduction), then it is
appended to ``deduction_stack``.
See Also
========
coincidence
"""
A_dict = self.A_dict
A_dict_inv = self.A_dict_inv
table = self.table
# behaves as a queue
q = []
self.merge(alpha, beta, q)
while len(q) > 0:
gamma = q.pop(0)
for x in A_dict:
delta = table[gamma][A_dict[x]]
if delta is not None:
table[delta][A_dict_inv[x]] = None
# only line of difference from ``coincidence`` routine
self.deduction_stack.append((delta, x**-1))
mu = self.rep(gamma)
nu = self.rep(delta)
if table[mu][A_dict[x]] is not None:
self.merge(nu, table[mu][A_dict[x]], q)
elif table[nu][A_dict_inv[x]] is not None:
self.merge(mu, table[nu][A_dict_inv[x]], q)
else:
table[mu][A_dict[x]] = nu
table[nu][A_dict_inv[x]] = mu
def scan(self, alpha, word, y=None, fill=False, modified=False):
r"""
``scan`` performs a scanning process on the input ``word``.
It first locates the largest prefix ``s`` of ``word`` for which
`\alpha^s` is defined (i.e is not ``None``), ``s`` may be empty. Let
``word=sv``, let ``t`` be the longest suffix of ``v`` for which
`\alpha^{t^{-1}}` is defined, and let ``v=ut``. Then three
possibilities are there:
1. If ``t=v``, then we say that the scan completes, and if, in addition
`\alpha^s = \alpha^{t^{-1}}`, then we say that the scan completes
correctly.
2. It can also happen that scan does not complete, but `|u|=1`; that
is, the word ``u`` consists of a single generator `x \in A`. In that
case, if `\alpha^s = \beta` and `\alpha^{t^{-1}} = \gamma`, then we can
set `\beta^x = \gamma` and `\gamma^{x^{-1}} = \beta`. These assignments
are known as deductions and enable the scan to complete correctly.
3. See ``coicidence`` routine for explanation of third condition.
Notes
=====
The code for the procedure of scanning `\alpha \in \Omega`
under `w \in A*` is defined on pg. 155 [1]
See Also
========
scan_c, scan_check, scan_and_fill, scan_and_fill_c
Scan and Fill
=============
Performed when the default argument fill=True.
Modified Scan
=============
Performed when the default argument modified=True
"""
# alpha is an integer representing a "coset"
# since scanning can be in two cases
# 1. for alpha=0 and w in Y (i.e generating set of H)
# 2. alpha in Omega (set of live cosets), w in R (relators)
A_dict = self.A_dict
A_dict_inv = self.A_dict_inv
table = self.table
f = alpha
i = 0
r = len(word)
b = alpha
j = r - 1
b_p = y
if modified:
f_p = self._grp.identity
flag = 0
while fill or flag == 0:
flag = 1
while i <= j and table[f][A_dict[word[i]]] is not None:
if modified:
f_p = f_p*self.P[f][A_dict[word[i]]]
f = table[f][A_dict[word[i]]]
i += 1
if i > j:
if f != b:
if modified:
self.modified_coincidence(f, b, f_p**-1*y)
else:
self.coincidence(f, b)
return
while j >= i and table[b][A_dict_inv[word[j]]] is not None:
if modified:
b_p = b_p*self.P[b][self.A_dict_inv[word[j]]]
b = table[b][A_dict_inv[word[j]]]
j -= 1
if j < i:
# we have an incorrect completed scan with coincidence f ~ b
# run the "coincidence" routine
if modified:
self.modified_coincidence(f, b, f_p**-1*b_p)
else:
self.coincidence(f, b)
elif j == i:
# deduction process
table[f][A_dict[word[i]]] = b
table[b][A_dict_inv[word[i]]] = f
if modified:
self.P[f][self.A_dict[word[i]]] = f_p**-1*b_p
self.P[b][self.A_dict_inv[word[i]]] = b_p**-1*f_p
return
elif fill:
self.define(f, word[i], modified=modified)
# otherwise scan is incomplete and yields no information
# used in the low-index subgroups algorithm
def scan_check(self, alpha, word):
r"""
Another version of ``scan`` routine, described on, it checks whether
`\alpha` scans correctly under `word`, it is a straightforward
modification of ``scan``. ``scan_check`` returns ``False`` (rather than
calling ``coincidence``) if the scan completes incorrectly; otherwise
it returns ``True``.
See Also
========
scan, scan_c, scan_and_fill, scan_and_fill_c
"""
# alpha is an integer representing a "coset"
# since scanning can be in two cases
# 1. for alpha=0 and w in Y (i.e generating set of H)
# 2. alpha in Omega (set of live cosets), w in R (relators)
A_dict = self.A_dict
A_dict_inv = self.A_dict_inv
table = self.table
f = alpha
i = 0
r = len(word)
b = alpha
j = r - 1
while i <= j and table[f][A_dict[word[i]]] is not None:
f = table[f][A_dict[word[i]]]
i += 1
if i > j:
return f == b
while j >= i and table[b][A_dict_inv[word[j]]] is not None:
b = table[b][A_dict_inv[word[j]]]
j -= 1
if j < i:
# we have an incorrect completed scan with coincidence f ~ b
# return False, instead of calling coincidence routine
return False
elif j == i:
# deduction process
table[f][A_dict[word[i]]] = b
table[b][A_dict_inv[word[i]]] = f
return True
def merge(self, k, lamda, q, w=None, modified=False):
"""
Merge two classes with representatives ``k`` and ``lamda``, described
on Pg. 157 [1] (for pseudocode), start by putting ``p[k] = lamda``.
It is more efficient to choose the new representative from the larger
of the two classes being merged, i.e larger among ``k`` and ``lamda``.
procedure ``merge`` performs the merging operation, adds the deleted
class representative to the queue ``q``.
Parameters
==========
'k', 'lamda' being the two class representatives to be merged.
Notes
=====
Pg. 86-87 [1] contains a description of this method.
See Also
========
coincidence, rep
"""
p = self.p
rep = self.rep
phi = rep(k, modified=modified)
psi = rep(lamda, modified=modified)
if phi != psi:
mu = min(phi, psi)
v = max(phi, psi)
p[v] = mu
if modified:
if v == phi:
self.p_p[phi] = self.p_p[k]**-1*w*self.p_p[lamda]
else:
self.p_p[psi] = self.p_p[lamda]**-1*w**-1*self.p_p[k]
q.append(v)
def rep(self, k, modified=False):
r"""
Parameters
==========
`k \in [0 \ldots n-1]`, as for ``self`` only array ``p`` is used
Returns
=======
Representative of the class containing ``k``.
Returns the representative of `\sim` class containing ``k``, it also
makes some modification to array ``p`` of ``self`` to ease further
computations, described on Pg. 157 [1].
The information on classes under `\sim` is stored in array `p` of
``self`` argument, which will always satisfy the property:
`p[\alpha] \sim \alpha` and `p[\alpha]=\alpha \iff \alpha=rep(\alpha)`
`\forall \in [0 \ldots n-1]`.
So, for `\alpha \in [0 \ldots n-1]`, we find `rep(self, \alpha)` by
continually replacing `\alpha` by `p[\alpha]` until it becomes
constant (i.e satisfies `p[\alpha] = \alpha`):w
To increase the efficiency of later ``rep`` calculations, whenever we
find `rep(self, \alpha)=\beta`, we set
`p[\gamma] = \beta \forall \gamma \in p-chain` from `\alpha` to `\beta`
Notes
=====
``rep`` routine is also described on Pg. 85-87 [1] in Atkinson's
algorithm, this results from the fact that ``coincidence`` routine
introduces functionality similar to that introduced by the
``minimal_block`` routine on Pg. 85-87 [1].
See Also
========
coincidence, merge
"""
p = self.p
lamda = k
rho = p[lamda]
if modified:
s = p[:]
while rho != lamda:
if modified:
s[rho] = lamda
lamda = rho
rho = p[lamda]
if modified:
rho = s[lamda]
while rho != k:
mu = rho
rho = s[mu]
p[rho] = lamda
self.p_p[rho] = self.p_p[rho]*self.p_p[mu]
else:
mu = k
rho = p[mu]
while rho != lamda:
p[mu] = lamda
mu = rho
rho = p[mu]
return lamda
# alpha, beta coincide, i.e. alpha, beta represent the pair of cosets
# where coincidence occurs
def coincidence(self, alpha, beta, w=None, modified=False):
r"""
The third situation described in ``scan`` routine is handled by this
routine, described on Pg. 156-161 [1].
The unfortunate situation when the scan completes but not correctly,
then ``coincidence`` routine is run. i.e when for some `i` with
`1 \le i \le r+1`, we have `w=st` with `s = x_1 x_2 \dots x_{i-1}`,
`t = x_i x_{i+1} \dots x_r`, and `\beta = \alpha^s` and
`\gamma = \alpha^{t-1}` are defined but unequal. This means that
`\beta` and `\gamma` represent the same coset of `H` in `G`. Described
on Pg. 156 [1]. ``rep``
See Also
========
scan
"""
A_dict = self.A_dict
A_dict_inv = self.A_dict_inv
table = self.table
# behaves as a queue
q = []
if modified:
self.modified_merge(alpha, beta, w, q)
else:
self.merge(alpha, beta, q)
while len(q) > 0:
gamma = q.pop(0)
for x in A_dict:
delta = table[gamma][A_dict[x]]
if delta is not None:
table[delta][A_dict_inv[x]] = None
mu = self.rep(gamma, modified=modified)
nu = self.rep(delta, modified=modified)
if table[mu][A_dict[x]] is not None:
if modified:
v = self.p_p[delta]**-1*self.P[gamma][self.A_dict[x]]**-1
v = v*self.p_p[gamma]*self.P[mu][self.A_dict[x]]
self.modified_merge(nu, table[mu][self.A_dict[x]], v, q)
else:
self.merge(nu, table[mu][A_dict[x]], q)
elif table[nu][A_dict_inv[x]] is not None:
if modified:
v = self.p_p[gamma]**-1*self.P[gamma][self.A_dict[x]]
v = v*self.p_p[delta]*self.P[mu][self.A_dict_inv[x]]
self.modified_merge(mu, table[nu][self.A_dict_inv[x]], v, q)
else:
self.merge(mu, table[nu][A_dict_inv[x]], q)
else:
table[mu][A_dict[x]] = nu
table[nu][A_dict_inv[x]] = mu
if modified:
v = self.p_p[gamma]**-1*self.P[gamma][self.A_dict[x]]*self.p_p[delta]
self.P[mu][self.A_dict[x]] = v
self.P[nu][self.A_dict_inv[x]] = v**-1
# method used in the HLT strategy
def scan_and_fill(self, alpha, word):
"""
A modified version of ``scan`` routine used in the relator-based
method of coset enumeration, described on pg. 162-163 [1], which
follows the idea that whenever the procedure is called and the scan
is incomplete then it makes new definitions to enable the scan to
complete; i.e it fills in the gaps in the scan of the relator or
subgroup generator.
"""
self.scan(alpha, word, fill=True)
def scan_and_fill_c(self, alpha, word):
"""
A modified version of ``scan`` routine, described on Pg. 165 second
para. [1], with modification similar to that of ``scan_anf_fill`` the
only difference being it calls the coincidence procedure used in the
coset-table based method i.e. the routine ``coincidence_c`` is used.
See Also
========
scan, scan_and_fill
"""
A_dict = self.A_dict
A_dict_inv = self.A_dict_inv
table = self.table
r = len(word)
f = alpha
i = 0
b = alpha
j = r - 1
# loop until it has filled the alpha row in the table.
while True:
# do the forward scanning
while i <= j and table[f][A_dict[word[i]]] is not None:
f = table[f][A_dict[word[i]]]
i += 1
if i > j:
if f != b:
self.coincidence_c(f, b)
return
# forward scan was incomplete, scan backwards
while j >= i and table[b][A_dict_inv[word[j]]] is not None:
b = table[b][A_dict_inv[word[j]]]
j -= 1
if j < i:
self.coincidence_c(f, b)
elif j == i:
table[f][A_dict[word[i]]] = b
table[b][A_dict_inv[word[i]]] = f
self.deduction_stack.append((f, word[i]))
else:
self.define_c(f, word[i])
# method used in the HLT strategy
def look_ahead(self):
"""
When combined with the HLT method this is known as HLT+Lookahead
method of coset enumeration, described on pg. 164 [1]. Whenever
``define`` aborts due to lack of space available this procedure is
executed. This routine helps in recovering space resulting from
"coincidence" of cosets.
"""
R = self.fp_group.relators
p = self.p
# complete scan all relators under all cosets(obviously live)
# without making new definitions
for beta in self.omega:
for w in R:
self.scan(beta, w)
if p[beta] < beta:
break
# Pg. 166
def process_deductions(self, R_c_x, R_c_x_inv):
"""
Processes the deductions that have been pushed onto ``deduction_stack``,
described on Pg. 166 [1] and is used in coset-table based enumeration.
See Also
========
deduction_stack
"""
p = self.p
table = self.table
while len(self.deduction_stack) > 0:
if len(self.deduction_stack) >= CosetTable.max_stack_size:
self.look_ahead()
del self.deduction_stack[:]
continue
else:
alpha, x = self.deduction_stack.pop()
if p[alpha] == alpha:
for w in R_c_x:
self.scan_c(alpha, w)
if p[alpha] < alpha:
break
beta = table[alpha][self.A_dict[x]]
if beta is not None and p[beta] == beta:
for w in R_c_x_inv:
self.scan_c(beta, w)
if p[beta] < beta:
break
def process_deductions_check(self, R_c_x, R_c_x_inv):
"""
A variation of ``process_deductions``, this calls ``scan_check``
wherever ``process_deductions`` calls ``scan``, described on Pg. [1].
See Also
========
process_deductions
"""
table = self.table
while len(self.deduction_stack) > 0:
alpha, x = self.deduction_stack.pop()
for w in R_c_x:
if not self.scan_check(alpha, w):
return False
beta = table[alpha][self.A_dict[x]]
if beta is not None:
for w in R_c_x_inv:
if not self.scan_check(beta, w):
return False
return True
def switch(self, beta, gamma):
r"""Switch the elements `\beta, \gamma \in \Omega` of ``self``, used
by the ``standardize`` procedure, described on Pg. 167 [1].
See Also
========
standardize
"""
A = self.A
A_dict = self.A_dict
table = self.table
for x in A:
z = table[gamma][A_dict[x]]
table[gamma][A_dict[x]] = table[beta][A_dict[x]]
table[beta][A_dict[x]] = z
for alpha in range(len(self.p)):
if self.p[alpha] == alpha:
if table[alpha][A_dict[x]] == beta:
table[alpha][A_dict[x]] = gamma
elif table[alpha][A_dict[x]] == gamma:
table[alpha][A_dict[x]] = beta
def standardize(self):
r"""
A coset table is standardized if when running through the cosets and
within each coset through the generator images (ignoring generator
inverses), the cosets appear in order of the integers
`0, 1, \dots, n`. "Standardize" reorders the elements of `\Omega`
such that, if we scan the coset table first by elements of `\Omega`
and then by elements of A, then the cosets occur in ascending order.
``standardize()`` is used at the end of an enumeration to permute the
cosets so that they occur in some sort of standard order.
Notes
=====
procedure is described on pg. 167-168 [1], it also makes use of the
``switch`` routine to replace by smaller integer value.
Examples
========
>>> from sympy.combinatorics import free_group
>>> from sympy.combinatorics.fp_groups import FpGroup, coset_enumeration_r
>>> F, x, y = free_group("x, y")
# Example 5.3 from [1]
>>> f = FpGroup(F, [x**2*y**2, x**3*y**5])
>>> C = coset_enumeration_r(f, [])
>>> C.compress()
>>> C.table
[[1, 3, 1, 3], [2, 0, 2, 0], [3, 1, 3, 1], [0, 2, 0, 2]]
>>> C.standardize()
>>> C.table
[[1, 2, 1, 2], [3, 0, 3, 0], [0, 3, 0, 3], [2, 1, 2, 1]]
"""
A = self.A
A_dict = self.A_dict
gamma = 1
for alpha, x in product(range(self.n), A):
beta = self.table[alpha][A_dict[x]]
if beta >= gamma:
if beta > gamma:
self.switch(gamma, beta)
gamma += 1
if gamma == self.n:
return
# Compression of a Coset Table
def compress(self):
"""Removes the non-live cosets from the coset table, described on
pg. 167 [1].
"""
gamma = -1
A = self.A
A_dict = self.A_dict
A_dict_inv = self.A_dict_inv
table = self.table
chi = tuple([i for i in range(len(self.p)) if self.p[i] != i])
for alpha in self.omega:
gamma += 1
if gamma != alpha:
# replace alpha by gamma in coset table
for x in A:
beta = table[alpha][A_dict[x]]
table[gamma][A_dict[x]] = beta
table[beta][A_dict_inv[x]] == gamma
# all the cosets in the table are live cosets
self.p = list(range(gamma + 1))
# delete the useless columns
del table[len(self.p):]
# re-define values
for row in table:
for j in range(len(self.A)):
row[j] -= bisect_left(chi, row[j])
def conjugates(self, R):
R_c = list(chain.from_iterable((rel.cyclic_conjugates(), \
(rel**-1).cyclic_conjugates()) for rel in R))
R_set = set()
for conjugate in R_c:
R_set = R_set.union(conjugate)
R_c_list = []
for x in self.A:
r = {word for word in R_set if word[0] == x}
R_c_list.append(r)
R_set.difference_update(r)
return R_c_list
def coset_representative(self, coset):
'''
Compute the coset representative of a given coset.
Examples
========
>>> from sympy.combinatorics import free_group
>>> from sympy.combinatorics.fp_groups import FpGroup, coset_enumeration_r
>>> F, x, y = free_group("x, y")
>>> f = FpGroup(F, [x**3, y**3, x**-1*y**-1*x*y])
>>> C = coset_enumeration_r(f, [x])
>>> C.compress()
>>> C.table
[[0, 0, 1, 2], [1, 1, 2, 0], [2, 2, 0, 1]]
>>> C.coset_representative(0)
<identity>
>>> C.coset_representative(1)
y
>>> C.coset_representative(2)
y**-1
'''
for x in self.A:
gamma = self.table[coset][self.A_dict[x]]
if coset == 0:
return self.fp_group.identity
if gamma < coset:
return self.coset_representative(gamma)*x**-1
##############################
# Modified Methods #
##############################
def modified_define(self, alpha, x):
r"""
Define a function p_p from from [1..n] to A* as
an additional component of the modified coset table.
Parameters
==========
\alpha \in \Omega
x \in A*
See Also
========
define
"""
self.define(alpha, x, modified=True)
def modified_scan(self, alpha, w, y, fill=False):
r"""
Parameters
==========
\alpha \in \Omega
w \in A*
y \in (YUY^-1)
fill -- `modified_scan_and_fill` when set to True.
See Also
========
scan
"""
self.scan(alpha, w, y=y, fill=fill, modified=True)
def modified_scan_and_fill(self, alpha, w, y):
self.modified_scan(alpha, w, y, fill=True)
def modified_merge(self, k, lamda, w, q):
r"""
Parameters
==========
'k', 'lamda' -- the two class representatives to be merged.
q -- queue of length l of elements to be deleted from `\Omega` *.
w -- Word in (YUY^-1)
See Also
========
merge
"""
self.merge(k, lamda, q, w=w, modified=True)
def modified_rep(self, k):
r"""
Parameters
==========
`k \in [0 \ldots n-1]`
See Also
========
rep
"""
self.rep(k, modified=True)
def modified_coincidence(self, alpha, beta, w):
r"""
Parameters
==========
A coincident pair `\alpha, \beta \in \Omega, w \in Y \cup Y^{-1}`
See Also
========
coincidence
"""
self.coincidence(alpha, beta, w=w, modified=True)
###############################################################################
# COSET ENUMERATION #
###############################################################################
# relator-based method
def coset_enumeration_r(fp_grp, Y, max_cosets=None, draft=None,
incomplete=False, modified=False):
"""
This is easier of the two implemented methods of coset enumeration.
and is often called the HLT method, after Hazelgrove, Leech, Trotter
The idea is that we make use of ``scan_and_fill`` makes new definitions
whenever the scan is incomplete to enable the scan to complete; this way
we fill in the gaps in the scan of the relator or subgroup generator,
that's why the name relator-based method.
An instance of `CosetTable` for `fp_grp` can be passed as the keyword
argument `draft` in which case the coset enumeration will start with
that instance and attempt to complete it.
When `incomplete` is `True` and the function is unable to complete for
some reason, the partially complete table will be returned.
# TODO: complete the docstring
See Also
========
scan_and_fill,
Examples
========
>>> from sympy.combinatorics.free_groups import free_group
>>> from sympy.combinatorics.fp_groups import FpGroup, coset_enumeration_r
>>> F, x, y = free_group("x, y")
# Example 5.1 from [1]
>>> f = FpGroup(F, [x**3, y**3, x**-1*y**-1*x*y])
>>> C = coset_enumeration_r(f, [x])
>>> for i in range(len(C.p)):
... if C.p[i] == i:
... print(C.table[i])
[0, 0, 1, 2]
[1, 1, 2, 0]
[2, 2, 0, 1]
>>> C.p
[0, 1, 2, 1, 1]
# Example from exercises Q2 [1]
>>> f = FpGroup(F, [x**2*y**2, y**-1*x*y*x**-3])
>>> C = coset_enumeration_r(f, [])
>>> C.compress(); C.standardize()
>>> C.table
[[1, 2, 3, 4],
[5, 0, 6, 7],
[0, 5, 7, 6],
[7, 6, 5, 0],
[6, 7, 0, 5],
[2, 1, 4, 3],
[3, 4, 2, 1],
[4, 3, 1, 2]]
# Example 5.2
>>> f = FpGroup(F, [x**2, y**3, (x*y)**3])
>>> Y = [x*y]
>>> C = coset_enumeration_r(f, Y)
>>> for i in range(len(C.p)):
... if C.p[i] == i:
... print(C.table[i])
[1, 1, 2, 1]
[0, 0, 0, 2]
[3, 3, 1, 0]
[2, 2, 3, 3]
# Example 5.3
>>> f = FpGroup(F, [x**2*y**2, x**3*y**5])
>>> Y = []
>>> C = coset_enumeration_r(f, Y)
>>> for i in range(len(C.p)):
... if C.p[i] == i:
... print(C.table[i])
[1, 3, 1, 3]
[2, 0, 2, 0]
[3, 1, 3, 1]
[0, 2, 0, 2]
# Example 5.4
>>> F, a, b, c, d, e = free_group("a, b, c, d, e")
>>> f = FpGroup(F, [a*b*c**-1, b*c*d**-1, c*d*e**-1, d*e*a**-1, e*a*b**-1])
>>> Y = [a]
>>> C = coset_enumeration_r(f, Y)
>>> for i in range(len(C.p)):
... if C.p[i] == i:
... print(C.table[i])
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
# example of "compress" method
>>> C.compress()
>>> C.table
[[0, 0, 0, 0, 0, 0, 0, 0, 0, 0]]
# Exercises Pg. 161, Q2.
>>> F, x, y = free_group("x, y")
>>> f = FpGroup(F, [x**2*y**2, y**-1*x*y*x**-3])
>>> Y = []
>>> C = coset_enumeration_r(f, Y)
>>> C.compress()
>>> C.standardize()
>>> C.table
[[1, 2, 3, 4],
[5, 0, 6, 7],
[0, 5, 7, 6],
[7, 6, 5, 0],
[6, 7, 0, 5],
[2, 1, 4, 3],
[3, 4, 2, 1],
[4, 3, 1, 2]]
# John J. Cannon; Lucien A. Dimino; George Havas; Jane M. Watson
# Mathematics of Computation, Vol. 27, No. 123. (Jul., 1973), pp. 463-490
# from 1973chwd.pdf
# Table 1. Ex. 1
>>> F, r, s, t = free_group("r, s, t")
>>> E1 = FpGroup(F, [t**-1*r*t*r**-2, r**-1*s*r*s**-2, s**-1*t*s*t**-2])
>>> C = coset_enumeration_r(E1, [r])
>>> for i in range(len(C.p)):
... if C.p[i] == i:
... print(C.table[i])
[0, 0, 0, 0, 0, 0]
Ex. 2
>>> F, a, b = free_group("a, b")
>>> Cox = FpGroup(F, [a**6, b**6, (a*b)**2, (a**2*b**2)**2, (a**3*b**3)**5])
>>> C = coset_enumeration_r(Cox, [a])
>>> index = 0
>>> for i in range(len(C.p)):
... if C.p[i] == i:
... index += 1
>>> index
500
# Ex. 3
>>> F, a, b = free_group("a, b")
>>> B_2_4 = FpGroup(F, [a**4, b**4, (a*b)**4, (a**-1*b)**4, (a**2*b)**4, \
(a*b**2)**4, (a**2*b**2)**4, (a**-1*b*a*b)**4, (a*b**-1*a*b)**4])
>>> C = coset_enumeration_r(B_2_4, [a])
>>> index = 0
>>> for i in range(len(C.p)):
... if C.p[i] == i:
... index += 1
>>> index
1024
References
==========
.. [1] Holt, D., Eick, B., O'Brien, E.
"Handbook of computational group theory"
"""
# 1. Initialize a coset table C for < X|R >
C = CosetTable(fp_grp, Y, max_cosets=max_cosets)
# Define coset table methods.
if modified:
_scan_and_fill = C.modified_scan_and_fill
_define = C.modified_define
else:
_scan_and_fill = C.scan_and_fill
_define = C.define
if draft:
C.table = draft.table[:]
C.p = draft.p[:]
R = fp_grp.relators
A_dict = C.A_dict
p = C.p
for i in range(len(Y)):
if modified:
_scan_and_fill(0, Y[i], C._grp.generators[i])
else:
_scan_and_fill(0, Y[i])
alpha = 0
while alpha < C.n:
if p[alpha] == alpha:
try:
for w in R:
if modified:
_scan_and_fill(alpha, w, C._grp.identity)
else:
_scan_and_fill(alpha, w)
# if alpha was eliminated during the scan then break
if p[alpha] < alpha:
break
if p[alpha] == alpha:
for x in A_dict:
if C.table[alpha][A_dict[x]] is None:
_define(alpha, x)
except ValueError as e:
if incomplete:
return C
raise e
alpha += 1
return C
def modified_coset_enumeration_r(fp_grp, Y, max_cosets=None, draft=None,
incomplete=False):
r"""
Introduce a new set of symbols y \in Y that correspond to the
generators of the subgroup. Store the elements of Y as a
word P[\alpha, x] and compute the coset table similar to that of
the regular coset enumeration methods.
Examples
========
>>> from sympy.combinatorics.free_groups import free_group
>>> from sympy.combinatorics.fp_groups import FpGroup
>>> from sympy.combinatorics.coset_table import modified_coset_enumeration_r
>>> F, x, y = free_group("x, y")
>>> f = FpGroup(F, [x**3, y**3, x**-1*y**-1*x*y])
>>> C = modified_coset_enumeration_r(f, [x])
>>> C.table
[[0, 0, 1, 2], [1, 1, 2, 0], [2, 2, 0, 1], [None, 1, None, None], [1, 3, None, None]]
See Also
========
coset_enumertation_r
References
==========
.. [1] Holt, D., Eick, B., O'Brien, E.,
"Handbook of Computational Group Theory",
Section 5.3.2
"""
return coset_enumeration_r(fp_grp, Y, max_cosets=max_cosets, draft=draft,
incomplete=incomplete, modified=True)
# Pg. 166
# coset-table based method
def coset_enumeration_c(fp_grp, Y, max_cosets=None, draft=None,
incomplete=False):
"""
>>> from sympy.combinatorics.free_groups import free_group
>>> from sympy.combinatorics.fp_groups import FpGroup, coset_enumeration_c
>>> F, x, y = free_group("x, y")
>>> f = FpGroup(F, [x**3, y**3, x**-1*y**-1*x*y])
>>> C = coset_enumeration_c(f, [x])
>>> C.table
[[0, 0, 1, 2], [1, 1, 2, 0], [2, 2, 0, 1]]
"""
# Initialize a coset table C for < X|R >
X = fp_grp.generators
R = fp_grp.relators
C = CosetTable(fp_grp, Y, max_cosets=max_cosets)
if draft:
C.table = draft.table[:]
C.p = draft.p[:]
C.deduction_stack = draft.deduction_stack
for alpha, x in product(range(len(C.table)), X):
if C.table[alpha][C.A_dict[x]] is not None:
C.deduction_stack.append((alpha, x))
A = C.A
# replace all the elements by cyclic reductions
R_cyc_red = [rel.identity_cyclic_reduction() for rel in R]
R_c = list(chain.from_iterable((rel.cyclic_conjugates(), (rel**-1).cyclic_conjugates()) \
for rel in R_cyc_red))
R_set = set()
for conjugate in R_c:
R_set = R_set.union(conjugate)
# a list of subsets of R_c whose words start with "x".
R_c_list = []
for x in C.A:
r = {word for word in R_set if word[0] == x}
R_c_list.append(r)
R_set.difference_update(r)
for w in Y:
C.scan_and_fill_c(0, w)
for x in A:
C.process_deductions(R_c_list[C.A_dict[x]], R_c_list[C.A_dict_inv[x]])
alpha = 0
while alpha < len(C.table):
if C.p[alpha] == alpha:
try:
for x in C.A:
if C.p[alpha] != alpha:
break
if C.table[alpha][C.A_dict[x]] is None:
C.define_c(alpha, x)
C.process_deductions(R_c_list[C.A_dict[x]], R_c_list[C.A_dict_inv[x]])
except ValueError as e:
if incomplete:
return C
raise e
alpha += 1
return C
PK ]ZZZ-��Vܺ ܺ sympy/combinatorics/fp_groups.py"""Finitely Presented Groups and its algorithms. """
from sympy.core.singleton import S
from sympy.core.symbol import symbols
from sympy.combinatorics.free_groups import (FreeGroup, FreeGroupElement,
free_group)
from sympy.combinatorics.rewritingsystem import RewritingSystem
from sympy.combinatorics.coset_table import (CosetTable,
coset_enumeration_r,
coset_enumeration_c)
from sympy.combinatorics import PermutationGroup
from sympy.matrices.normalforms import invariant_factors
from sympy.matrices import Matrix
from sympy.polys.polytools import gcd
from sympy.printing.defaults import DefaultPrinting
from sympy.utilities import public
from sympy.utilities.magic import pollute
from itertools import product
@public
def fp_group(fr_grp, relators=()):
_fp_group = FpGroup(fr_grp, relators)
return (_fp_group,) + tuple(_fp_group._generators)
@public
def xfp_group(fr_grp, relators=()):
_fp_group = FpGroup(fr_grp, relators)
return (_fp_group, _fp_group._generators)
# Does not work. Both symbols and pollute are undefined. Never tested.
@public
def vfp_group(fr_grpm, relators):
_fp_group = FpGroup(symbols, relators)
pollute([sym.name for sym in _fp_group.symbols], _fp_group.generators)
return _fp_group
def _parse_relators(rels):
"""Parse the passed relators."""
return rels
###############################################################################
# FINITELY PRESENTED GROUPS #
###############################################################################
class FpGroup(DefaultPrinting):
"""
The FpGroup would take a FreeGroup and a list/tuple of relators, the
relators would be specified in such a way that each of them be equal to the
identity of the provided free group.
"""
is_group = True
is_FpGroup = True
is_PermutationGroup = False
def __init__(self, fr_grp, relators):
relators = _parse_relators(relators)
self.free_group = fr_grp
self.relators = relators
self.generators = self._generators()
self.dtype = type("FpGroupElement", (FpGroupElement,), {"group": self})
# CosetTable instance on identity subgroup
self._coset_table = None
# returns whether coset table on identity subgroup
# has been standardized
self._is_standardized = False
self._order = None
self._center = None
self._rewriting_system = RewritingSystem(self)
self._perm_isomorphism = None
return
def _generators(self):
return self.free_group.generators
def make_confluent(self):
'''
Try to make the group's rewriting system confluent
'''
self._rewriting_system.make_confluent()
return
def reduce(self, word):
'''
Return the reduced form of `word` in `self` according to the group's
rewriting system. If it's confluent, the reduced form is the unique normal
form of the word in the group.
'''
return self._rewriting_system.reduce(word)
def equals(self, word1, word2):
'''
Compare `word1` and `word2` for equality in the group
using the group's rewriting system. If the system is
confluent, the returned answer is necessarily correct.
(If it is not, `False` could be returned in some cases
where in fact `word1 == word2`)
'''
if self.reduce(word1*word2**-1) == self.identity:
return True
elif self._rewriting_system.is_confluent:
return False
return None
@property
def identity(self):
return self.free_group.identity
def __contains__(self, g):
return g in self.free_group
def subgroup(self, gens, C=None, homomorphism=False):
'''
Return the subgroup generated by `gens` using the
Reidemeister-Schreier algorithm
homomorphism -- When set to True, return a dictionary containing the images
of the presentation generators in the original group.
Examples
========
>>> from sympy.combinatorics.fp_groups import FpGroup
>>> from sympy.combinatorics import free_group
>>> F, x, y = free_group("x, y")
>>> f = FpGroup(F, [x**3, y**5, (x*y)**2])
>>> H = [x*y, x**-1*y**-1*x*y*x]
>>> K, T = f.subgroup(H, homomorphism=True)
>>> T(K.generators)
[x*y, x**-1*y**2*x**-1]
'''
if not all(isinstance(g, FreeGroupElement) for g in gens):
raise ValueError("Generators must be `FreeGroupElement`s")
if not all(g.group == self.free_group for g in gens):
raise ValueError("Given generators are not members of the group")
if homomorphism:
g, rels, _gens = reidemeister_presentation(self, gens, C=C, homomorphism=True)
else:
g, rels = reidemeister_presentation(self, gens, C=C)
if g:
g = FpGroup(g[0].group, rels)
else:
g = FpGroup(free_group('')[0], [])
if homomorphism:
from sympy.combinatorics.homomorphisms import homomorphism
return g, homomorphism(g, self, g.generators, _gens, check=False)
return g
def coset_enumeration(self, H, strategy="relator_based", max_cosets=None,
draft=None, incomplete=False):
"""
Return an instance of ``coset table``, when Todd-Coxeter algorithm is
run over the ``self`` with ``H`` as subgroup, using ``strategy``
argument as strategy. The returned coset table is compressed but not
standardized.
An instance of `CosetTable` for `fp_grp` can be passed as the keyword
argument `draft` in which case the coset enumeration will start with
that instance and attempt to complete it.
When `incomplete` is `True` and the function is unable to complete for
some reason, the partially complete table will be returned.
"""
if not max_cosets:
max_cosets = CosetTable.coset_table_max_limit
if strategy == 'relator_based':
C = coset_enumeration_r(self, H, max_cosets=max_cosets,
draft=draft, incomplete=incomplete)
else:
C = coset_enumeration_c(self, H, max_cosets=max_cosets,
draft=draft, incomplete=incomplete)
if C.is_complete():
C.compress()
return C
def standardize_coset_table(self):
"""
Standardized the coset table ``self`` and makes the internal variable
``_is_standardized`` equal to ``True``.
"""
self._coset_table.standardize()
self._is_standardized = True
def coset_table(self, H, strategy="relator_based", max_cosets=None,
draft=None, incomplete=False):
"""
Return the mathematical coset table of ``self`` in ``H``.
"""
if not H:
if self._coset_table is not None:
if not self._is_standardized:
self.standardize_coset_table()
else:
C = self.coset_enumeration([], strategy, max_cosets=max_cosets,
draft=draft, incomplete=incomplete)
self._coset_table = C
self.standardize_coset_table()
return self._coset_table.table
else:
C = self.coset_enumeration(H, strategy, max_cosets=max_cosets,
draft=draft, incomplete=incomplete)
C.standardize()
return C.table
def order(self, strategy="relator_based"):
"""
Returns the order of the finitely presented group ``self``. It uses
the coset enumeration with identity group as subgroup, i.e ``H=[]``.
Examples
========
>>> from sympy.combinatorics import free_group
>>> from sympy.combinatorics.fp_groups import FpGroup
>>> F, x, y = free_group("x, y")
>>> f = FpGroup(F, [x, y**2])
>>> f.order(strategy="coset_table_based")
2
"""
if self._order is not None:
return self._order
if self._coset_table is not None:
self._order = len(self._coset_table.table)
elif len(self.relators) == 0:
self._order = self.free_group.order()
elif len(self.generators) == 1:
self._order = abs(gcd([r.array_form[0][1] for r in self.relators]))
elif self._is_infinite():
self._order = S.Infinity
else:
gens, C = self._finite_index_subgroup()
if C:
ind = len(C.table)
self._order = ind*self.subgroup(gens, C=C).order()
else:
self._order = self.index([])
return self._order
def _is_infinite(self):
'''
Test if the group is infinite. Return `True` if the test succeeds
and `None` otherwise
'''
used_gens = set()
for r in self.relators:
used_gens.update(r.contains_generators())
if not set(self.generators) <= used_gens:
return True
# Abelianisation test: check is the abelianisation is infinite
abelian_rels = []
for rel in self.relators:
abelian_rels.append([rel.exponent_sum(g) for g in self.generators])
m = Matrix(Matrix(abelian_rels))
if 0 in invariant_factors(m):
return True
else:
return None
def _finite_index_subgroup(self, s=None):
'''
Find the elements of `self` that generate a finite index subgroup
and, if found, return the list of elements and the coset table of `self` by
the subgroup, otherwise return `(None, None)`
'''
gen = self.most_frequent_generator()
rels = list(self.generators)
rels.extend(self.relators)
if not s:
if len(self.generators) == 2:
s = [gen] + [g for g in self.generators if g != gen]
else:
rand = self.free_group.identity
i = 0
while ((rand in rels or rand**-1 in rels or rand.is_identity)
and i<10):
rand = self.random()
i += 1
s = [gen, rand] + [g for g in self.generators if g != gen]
mid = (len(s)+1)//2
half1 = s[:mid]
half2 = s[mid:]
draft1 = None
draft2 = None
m = 200
C = None
while not C and (m/2 < CosetTable.coset_table_max_limit):
m = min(m, CosetTable.coset_table_max_limit)
draft1 = self.coset_enumeration(half1, max_cosets=m,
draft=draft1, incomplete=True)
if draft1.is_complete():
C = draft1
half = half1
else:
draft2 = self.coset_enumeration(half2, max_cosets=m,
draft=draft2, incomplete=True)
if draft2.is_complete():
C = draft2
half = half2
if not C:
m *= 2
if not C:
return None, None
C.compress()
return half, C
def most_frequent_generator(self):
gens = self.generators
rels = self.relators
freqs = [sum(r.generator_count(g) for r in rels) for g in gens]
return gens[freqs.index(max(freqs))]
def random(self):
import random
r = self.free_group.identity
for i in range(random.randint(2,3)):
r = r*random.choice(self.generators)**random.choice([1,-1])
return r
def index(self, H, strategy="relator_based"):
"""
Return the index of subgroup ``H`` in group ``self``.
Examples
========
>>> from sympy.combinatorics import free_group
>>> from sympy.combinatorics.fp_groups import FpGroup
>>> F, x, y = free_group("x, y")
>>> f = FpGroup(F, [x**5, y**4, y*x*y**3*x**3])
>>> f.index([x])
4
"""
# TODO: use |G:H| = |G|/|H| (currently H can't be made into a group)
# when we know |G| and |H|
if H == []:
return self.order()
else:
C = self.coset_enumeration(H, strategy)
return len(C.table)
def __str__(self):
if self.free_group.rank > 30:
str_form = "<fp group with %s generators>" % self.free_group.rank
else:
str_form = "<fp group on the generators %s>" % str(self.generators)
return str_form
__repr__ = __str__
#==============================================================================
# PERMUTATION GROUP METHODS
#==============================================================================
def _to_perm_group(self):
'''
Return an isomorphic permutation group and the isomorphism.
The implementation is dependent on coset enumeration so
will only terminate for finite groups.
'''
from sympy.combinatorics import Permutation
from sympy.combinatorics.homomorphisms import homomorphism
if self.order() is S.Infinity:
raise NotImplementedError("Permutation presentation of infinite "
"groups is not implemented")
if self._perm_isomorphism:
T = self._perm_isomorphism
P = T.image()
else:
C = self.coset_table([])
gens = self.generators
images = [[C[i][2*gens.index(g)] for i in range(len(C))] for g in gens]
images = [Permutation(i) for i in images]
P = PermutationGroup(images)
T = homomorphism(self, P, gens, images, check=False)
self._perm_isomorphism = T
return P, T
def _perm_group_list(self, method_name, *args):
'''
Given the name of a `PermutationGroup` method (returning a subgroup
or a list of subgroups) and (optionally) additional arguments it takes,
return a list or a list of lists containing the generators of this (or
these) subgroups in terms of the generators of `self`.
'''
P, T = self._to_perm_group()
perm_result = getattr(P, method_name)(*args)
single = False
if isinstance(perm_result, PermutationGroup):
perm_result, single = [perm_result], True
result = []
for group in perm_result:
gens = group.generators
result.append(T.invert(gens))
return result[0] if single else result
def derived_series(self):
'''
Return the list of lists containing the generators
of the subgroups in the derived series of `self`.
'''
return self._perm_group_list('derived_series')
def lower_central_series(self):
'''
Return the list of lists containing the generators
of the subgroups in the lower central series of `self`.
'''
return self._perm_group_list('lower_central_series')
def center(self):
'''
Return the list of generators of the center of `self`.
'''
return self._perm_group_list('center')
def derived_subgroup(self):
'''
Return the list of generators of the derived subgroup of `self`.
'''
return self._perm_group_list('derived_subgroup')
def centralizer(self, other):
'''
Return the list of generators of the centralizer of `other`
(a list of elements of `self`) in `self`.
'''
T = self._to_perm_group()[1]
other = T(other)
return self._perm_group_list('centralizer', other)
def normal_closure(self, other):
'''
Return the list of generators of the normal closure of `other`
(a list of elements of `self`) in `self`.
'''
T = self._to_perm_group()[1]
other = T(other)
return self._perm_group_list('normal_closure', other)
def _perm_property(self, attr):
'''
Given an attribute of a `PermutationGroup`, return
its value for a permutation group isomorphic to `self`.
'''
P = self._to_perm_group()[0]
return getattr(P, attr)
@property
def is_abelian(self):
'''
Check if `self` is abelian.
'''
return self._perm_property("is_abelian")
@property
def is_nilpotent(self):
'''
Check if `self` is nilpotent.
'''
return self._perm_property("is_nilpotent")
@property
def is_solvable(self):
'''
Check if `self` is solvable.
'''
return self._perm_property("is_solvable")
@property
def elements(self):
'''
List the elements of `self`.
'''
P, T = self._to_perm_group()
return T.invert(P.elements)
@property
def is_cyclic(self):
"""
Return ``True`` if group is Cyclic.
"""
if len(self.generators) <= 1:
return True
try:
P, T = self._to_perm_group()
except NotImplementedError:
raise NotImplementedError("Check for infinite Cyclic group "
"is not implemented")
return P.is_cyclic
def abelian_invariants(self):
"""
Return Abelian Invariants of a group.
"""
try:
P, T = self._to_perm_group()
except NotImplementedError:
raise NotImplementedError("abelian invariants is not implemented"
"for infinite group")
return P.abelian_invariants()
def composition_series(self):
"""
Return subnormal series of maximum length for a group.
"""
try:
P, T = self._to_perm_group()
except NotImplementedError:
raise NotImplementedError("composition series is not implemented"
"for infinite group")
return P.composition_series()
class FpSubgroup(DefaultPrinting):
'''
The class implementing a subgroup of an FpGroup or a FreeGroup
(only finite index subgroups are supported at this point). This
is to be used if one wishes to check if an element of the original
group belongs to the subgroup
'''
def __init__(self, G, gens, normal=False):
super().__init__()
self.parent = G
self.generators = list({g for g in gens if g != G.identity})
self._min_words = None #for use in __contains__
self.C = None
self.normal = normal
def __contains__(self, g):
if isinstance(self.parent, FreeGroup):
if self._min_words is None:
# make _min_words - a list of subwords such that
# g is in the subgroup if and only if it can be
# partitioned into these subwords. Infinite families of
# subwords are presented by tuples, e.g. (r, w)
# stands for the family of subwords r*w**n*r**-1
def _process(w):
# this is to be used before adding new words
# into _min_words; if the word w is not cyclically
# reduced, it will generate an infinite family of
# subwords so should be written as a tuple;
# if it is, w**-1 should be added to the list
# as well
p, r = w.cyclic_reduction(removed=True)
if not r.is_identity:
return [(r, p)]
else:
return [w, w**-1]
# make the initial list
gens = []
for w in self.generators:
if self.normal:
w = w.cyclic_reduction()
gens.extend(_process(w))
for w1 in gens:
for w2 in gens:
# if w1 and w2 are equal or are inverses, continue
if w1 == w2 or (not isinstance(w1, tuple)
and w1**-1 == w2):
continue
# if the start of one word is the inverse of the
# end of the other, their multiple should be added
# to _min_words because of cancellation
if isinstance(w1, tuple):
# start, end
s1, s2 = w1[0][0], w1[0][0]**-1
else:
s1, s2 = w1[0], w1[len(w1)-1]
if isinstance(w2, tuple):
# start, end
r1, r2 = w2[0][0], w2[0][0]**-1
else:
r1, r2 = w2[0], w2[len(w1)-1]
# p1 and p2 are w1 and w2 or, in case when
# w1 or w2 is an infinite family, a representative
p1, p2 = w1, w2
if isinstance(w1, tuple):
p1 = w1[0]*w1[1]*w1[0]**-1
if isinstance(w2, tuple):
p2 = w2[0]*w2[1]*w2[0]**-1
# add the product of the words to the list is necessary
if r1**-1 == s2 and not (p1*p2).is_identity:
new = _process(p1*p2)
if new not in gens:
gens.extend(new)
if r2**-1 == s1 and not (p2*p1).is_identity:
new = _process(p2*p1)
if new not in gens:
gens.extend(new)
self._min_words = gens
min_words = self._min_words
def _is_subword(w):
# check if w is a word in _min_words or one of
# the infinite families in it
w, r = w.cyclic_reduction(removed=True)
if r.is_identity or self.normal:
return w in min_words
else:
t = [s[1] for s in min_words if isinstance(s, tuple)
and s[0] == r]
return [s for s in t if w.power_of(s)] != []
# store the solution of words for which the result of
# _word_break (below) is known
known = {}
def _word_break(w):
# check if w can be written as a product of words
# in min_words
if len(w) == 0:
return True
i = 0
while i < len(w):
i += 1
prefix = w.subword(0, i)
if not _is_subword(prefix):
continue
rest = w.subword(i, len(w))
if rest not in known:
known[rest] = _word_break(rest)
if known[rest]:
return True
return False
if self.normal:
g = g.cyclic_reduction()
return _word_break(g)
else:
if self.C is None:
C = self.parent.coset_enumeration(self.generators)
self.C = C
i = 0
C = self.C
for j in range(len(g)):
i = C.table[i][C.A_dict[g[j]]]
return i == 0
def order(self):
if not self.generators:
return S.One
if isinstance(self.parent, FreeGroup):
return S.Infinity
if self.C is None:
C = self.parent.coset_enumeration(self.generators)
self.C = C
# This is valid because `len(self.C.table)` (the index of the subgroup)
# will always be finite - otherwise coset enumeration doesn't terminate
return self.parent.order()/len(self.C.table)
def to_FpGroup(self):
if isinstance(self.parent, FreeGroup):
gen_syms = [('x_%d'%i) for i in range(len(self.generators))]
return free_group(', '.join(gen_syms))[0]
return self.parent.subgroup(C=self.C)
def __str__(self):
if len(self.generators) > 30:
str_form = "<fp subgroup with %s generators>" % len(self.generators)
else:
str_form = "<fp subgroup on the generators %s>" % str(self.generators)
return str_form
__repr__ = __str__
###############################################################################
# LOW INDEX SUBGROUPS #
###############################################################################
def low_index_subgroups(G, N, Y=()):
"""
Implements the Low Index Subgroups algorithm, i.e find all subgroups of
``G`` upto a given index ``N``. This implements the method described in
[Sim94]. This procedure involves a backtrack search over incomplete Coset
Tables, rather than over forced coincidences.
Parameters
==========
G: An FpGroup < X|R >
N: positive integer, representing the maximum index value for subgroups
Y: (an optional argument) specifying a list of subgroup generators, such
that each of the resulting subgroup contains the subgroup generated by Y.
Examples
========
>>> from sympy.combinatorics import free_group
>>> from sympy.combinatorics.fp_groups import FpGroup, low_index_subgroups
>>> F, x, y = free_group("x, y")
>>> f = FpGroup(F, [x**2, y**3, (x*y)**4])
>>> L = low_index_subgroups(f, 4)
>>> for coset_table in L:
... print(coset_table.table)
[[0, 0, 0, 0]]
[[0, 0, 1, 2], [1, 1, 2, 0], [3, 3, 0, 1], [2, 2, 3, 3]]
[[0, 0, 1, 2], [2, 2, 2, 0], [1, 1, 0, 1]]
[[1, 1, 0, 0], [0, 0, 1, 1]]
References
==========
.. [1] Holt, D., Eick, B., O'Brien, E.
"Handbook of Computational Group Theory"
Section 5.4
.. [2] Marston Conder and Peter Dobcsanyi
"Applications and Adaptions of the Low Index Subgroups Procedure"
"""
C = CosetTable(G, [])
R = G.relators
# length chosen for the length of the short relators
len_short_rel = 5
# elements of R2 only checked at the last step for complete
# coset tables
R2 = {rel for rel in R if len(rel) > len_short_rel}
# elements of R1 are used in inner parts of the process to prune
# branches of the search tree,
R1 = {rel.identity_cyclic_reduction() for rel in set(R) - R2}
R1_c_list = C.conjugates(R1)
S = []
descendant_subgroups(S, C, R1_c_list, C.A[0], R2, N, Y)
return S
def descendant_subgroups(S, C, R1_c_list, x, R2, N, Y):
A_dict = C.A_dict
A_dict_inv = C.A_dict_inv
if C.is_complete():
# if C is complete then it only needs to test
# whether the relators in R2 are satisfied
for w, alpha in product(R2, C.omega):
if not C.scan_check(alpha, w):
return
# relators in R2 are satisfied, append the table to list
S.append(C)
else:
# find the first undefined entry in Coset Table
for alpha, x in product(range(len(C.table)), C.A):
if C.table[alpha][A_dict[x]] is None:
# this is "x" in pseudo-code (using "y" makes it clear)
undefined_coset, undefined_gen = alpha, x
break
# for filling up the undefine entry we try all possible values
# of beta in Omega or beta = n where beta^(undefined_gen^-1) is undefined
reach = C.omega + [C.n]
for beta in reach:
if beta < N:
if beta == C.n or C.table[beta][A_dict_inv[undefined_gen]] is None:
try_descendant(S, C, R1_c_list, R2, N, undefined_coset, \
undefined_gen, beta, Y)
def try_descendant(S, C, R1_c_list, R2, N, alpha, x, beta, Y):
r"""
Solves the problem of trying out each individual possibility
for `\alpha^x.
"""
D = C.copy()
if beta == D.n and beta < N:
D.table.append([None]*len(D.A))
D.p.append(beta)
D.table[alpha][D.A_dict[x]] = beta
D.table[beta][D.A_dict_inv[x]] = alpha
D.deduction_stack.append((alpha, x))
if not D.process_deductions_check(R1_c_list[D.A_dict[x]], \
R1_c_list[D.A_dict_inv[x]]):
return
for w in Y:
if not D.scan_check(0, w):
return
if first_in_class(D, Y):
descendant_subgroups(S, D, R1_c_list, x, R2, N, Y)
def first_in_class(C, Y=()):
"""
Checks whether the subgroup ``H=G1`` corresponding to the Coset Table
could possibly be the canonical representative of its conjugacy class.
Parameters
==========
C: CosetTable
Returns
=======
bool: True/False
If this returns False, then no descendant of C can have that property, and
so we can abandon C. If it returns True, then we need to process further
the node of the search tree corresponding to C, and so we call
``descendant_subgroups`` recursively on C.
Examples
========
>>> from sympy.combinatorics import free_group
>>> from sympy.combinatorics.fp_groups import FpGroup, CosetTable, first_in_class
>>> F, x, y = free_group("x, y")
>>> f = FpGroup(F, [x**2, y**3, (x*y)**4])
>>> C = CosetTable(f, [])
>>> C.table = [[0, 0, None, None]]
>>> first_in_class(C)
True
>>> C.table = [[1, 1, 1, None], [0, 0, None, 1]]; C.p = [0, 1]
>>> first_in_class(C)
True
>>> C.table = [[1, 1, 2, 1], [0, 0, 0, None], [None, None, None, 0]]
>>> C.p = [0, 1, 2]
>>> first_in_class(C)
False
>>> C.table = [[1, 1, 1, 2], [0, 0, 2, 0], [2, None, 0, 1]]
>>> first_in_class(C)
False
# TODO:: Sims points out in [Sim94] that performance can be improved by
# remembering some of the information computed by ``first_in_class``. If
# the ``continue alpha`` statement is executed at line 14, then the same thing
# will happen for that value of alpha in any descendant of the table C, and so
# the values the values of alpha for which this occurs could profitably be
# stored and passed through to the descendants of C. Of course this would
# make the code more complicated.
# The code below is taken directly from the function on page 208 of [Sim94]
# nu[alpha]
"""
n = C.n
# lamda is the largest numbered point in Omega_c_alpha which is currently defined
lamda = -1
# for alpha in Omega_c, nu[alpha] is the point in Omega_c_alpha corresponding to alpha
nu = [None]*n
# for alpha in Omega_c_alpha, mu[alpha] is the point in Omega_c corresponding to alpha
mu = [None]*n
# mutually nu and mu are the mutually-inverse equivalence maps between
# Omega_c_alpha and Omega_c
next_alpha = False
# For each 0!=alpha in [0 .. nc-1], we start by constructing the equivalent
# standardized coset table C_alpha corresponding to H_alpha
for alpha in range(1, n):
# reset nu to "None" after previous value of alpha
for beta in range(lamda+1):
nu[mu[beta]] = None
# we only want to reject our current table in favour of a preceding
# table in the ordering in which 1 is replaced by alpha, if the subgroup
# G_alpha corresponding to this preceding table definitely contains the
# given subgroup
for w in Y:
# TODO: this should support input of a list of general words
# not just the words which are in "A" (i.e gen and gen^-1)
if C.table[alpha][C.A_dict[w]] != alpha:
# continue with alpha
next_alpha = True
break
if next_alpha:
next_alpha = False
continue
# try alpha as the new point 0 in Omega_C_alpha
mu[0] = alpha
nu[alpha] = 0
# compare corresponding entries in C and C_alpha
lamda = 0
for beta in range(n):
for x in C.A:
gamma = C.table[beta][C.A_dict[x]]
delta = C.table[mu[beta]][C.A_dict[x]]
# if either of the entries is undefined,
# we move with next alpha
if gamma is None or delta is None:
# continue with alpha
next_alpha = True
break
if nu[delta] is None:
# delta becomes the next point in Omega_C_alpha
lamda += 1
nu[delta] = lamda
mu[lamda] = delta
if nu[delta] < gamma:
return False
if nu[delta] > gamma:
# continue with alpha
next_alpha = True
break
if next_alpha:
next_alpha = False
break
return True
#========================================================================
# Simplifying Presentation
#========================================================================
def simplify_presentation(*args, change_gens=False):
'''
For an instance of `FpGroup`, return a simplified isomorphic copy of
the group (e.g. remove redundant generators or relators). Alternatively,
a list of generators and relators can be passed in which case the
simplified lists will be returned.
By default, the generators of the group are unchanged. If you would
like to remove redundant generators, set the keyword argument
`change_gens = True`.
'''
if len(args) == 1:
if not isinstance(args[0], FpGroup):
raise TypeError("The argument must be an instance of FpGroup")
G = args[0]
gens, rels = simplify_presentation(G.generators, G.relators,
change_gens=change_gens)
if gens:
return FpGroup(gens[0].group, rels)
return FpGroup(FreeGroup([]), [])
elif len(args) == 2:
gens, rels = args[0][:], args[1][:]
if not gens:
return gens, rels
identity = gens[0].group.identity
else:
if len(args) == 0:
m = "Not enough arguments"
else:
m = "Too many arguments"
raise RuntimeError(m)
prev_gens = []
prev_rels = []
while not set(prev_rels) == set(rels):
prev_rels = rels
while change_gens and not set(prev_gens) == set(gens):
prev_gens = gens
gens, rels = elimination_technique_1(gens, rels, identity)
rels = _simplify_relators(rels)
if change_gens:
syms = [g.array_form[0][0] for g in gens]
F = free_group(syms)[0]
identity = F.identity
gens = F.generators
subs = dict(zip(syms, gens))
for j, r in enumerate(rels):
a = r.array_form
rel = identity
for sym, p in a:
rel = rel*subs[sym]**p
rels[j] = rel
return gens, rels
def _simplify_relators(rels):
"""
Simplifies a set of relators. All relators are checked to see if they are
of the form `gen^n`. If any such relators are found then all other relators
are processed for strings in the `gen` known order.
Examples
========
>>> from sympy.combinatorics import free_group
>>> from sympy.combinatorics.fp_groups import _simplify_relators
>>> F, x, y = free_group("x, y")
>>> w1 = [x**2*y**4, x**3]
>>> _simplify_relators(w1)
[x**3, x**-1*y**4]
>>> w2 = [x**2*y**-4*x**5, x**3, x**2*y**8, y**5]
>>> _simplify_relators(w2)
[x**-1*y**-2, x**-1*y*x**-1, x**3, y**5]
>>> w3 = [x**6*y**4, x**4]
>>> _simplify_relators(w3)
[x**4, x**2*y**4]
>>> w4 = [x**2, x**5, y**3]
>>> _simplify_relators(w4)
[x, y**3]
"""
rels = rels[:]
if not rels:
return []
identity = rels[0].group.identity
# build dictionary with "gen: n" where gen^n is one of the relators
exps = {}
for i in range(len(rels)):
rel = rels[i]
if rel.number_syllables() == 1:
g = rel[0]
exp = abs(rel.array_form[0][1])
if rel.array_form[0][1] < 0:
rels[i] = rels[i]**-1
g = g**-1
if g in exps:
exp = gcd(exp, exps[g].array_form[0][1])
exps[g] = g**exp
one_syllables_words = list(exps.values())
# decrease some of the exponents in relators, making use of the single
# syllable relators
for i, rel in enumerate(rels):
if rel in one_syllables_words:
continue
rel = rel.eliminate_words(one_syllables_words, _all = True)
# if rels[i] contains g**n where abs(n) is greater than half of the power p
# of g in exps, g**n can be replaced by g**(n-p) (or g**(p-n) if n<0)
for g in rel.contains_generators():
if g in exps:
exp = exps[g].array_form[0][1]
max_exp = (exp + 1)//2
rel = rel.eliminate_word(g**(max_exp), g**(max_exp-exp), _all = True)
rel = rel.eliminate_word(g**(-max_exp), g**(-(max_exp-exp)), _all = True)
rels[i] = rel
rels = [r.identity_cyclic_reduction() for r in rels]
rels += one_syllables_words # include one_syllable_words in the list of relators
rels = list(set(rels)) # get unique values in rels
rels.sort()
# remove <identity> entries in rels
try:
rels.remove(identity)
except ValueError:
pass
return rels
# Pg 350, section 2.5.1 from [2]
def elimination_technique_1(gens, rels, identity):
rels = rels[:]
# the shorter relators are examined first so that generators selected for
# elimination will have shorter strings as equivalent
rels.sort()
gens = gens[:]
redundant_gens = {}
redundant_rels = []
used_gens = set()
# examine each relator in relator list for any generator occurring exactly
# once
for rel in rels:
# don't look for a redundant generator in a relator which
# depends on previously found ones
contained_gens = rel.contains_generators()
if any(g in contained_gens for g in redundant_gens):
continue
contained_gens = list(contained_gens)
contained_gens.sort(reverse = True)
for gen in contained_gens:
if rel.generator_count(gen) == 1 and gen not in used_gens:
k = rel.exponent_sum(gen)
gen_index = rel.index(gen**k)
bk = rel.subword(gen_index + 1, len(rel))
fw = rel.subword(0, gen_index)
chi = bk*fw
redundant_gens[gen] = chi**(-1*k)
used_gens.update(chi.contains_generators())
redundant_rels.append(rel)
break
rels = [r for r in rels if r not in redundant_rels]
# eliminate the redundant generators from remaining relators
rels = [r.eliminate_words(redundant_gens, _all = True).identity_cyclic_reduction() for r in rels]
rels = list(set(rels))
try:
rels.remove(identity)
except ValueError:
pass
gens = [g for g in gens if g not in redundant_gens]
return gens, rels
###############################################################################
# SUBGROUP PRESENTATIONS #
###############################################################################
# Pg 175 [1]
def define_schreier_generators(C, homomorphism=False):
'''
Parameters
==========
C -- Coset table.
homomorphism -- When set to True, return a dictionary containing the images
of the presentation generators in the original group.
'''
y = []
gamma = 1
f = C.fp_group
X = f.generators
if homomorphism:
# `_gens` stores the elements of the parent group to
# to which the schreier generators correspond to.
_gens = {}
# compute the schreier Traversal
tau = {}
tau[0] = f.identity
C.P = [[None]*len(C.A) for i in range(C.n)]
for alpha, x in product(C.omega, C.A):
beta = C.table[alpha][C.A_dict[x]]
if beta == gamma:
C.P[alpha][C.A_dict[x]] = "<identity>"
C.P[beta][C.A_dict_inv[x]] = "<identity>"
gamma += 1
if homomorphism:
tau[beta] = tau[alpha]*x
elif x in X and C.P[alpha][C.A_dict[x]] is None:
y_alpha_x = '%s_%s' % (x, alpha)
y.append(y_alpha_x)
C.P[alpha][C.A_dict[x]] = y_alpha_x
if homomorphism:
_gens[y_alpha_x] = tau[alpha]*x*tau[beta]**-1
grp_gens = list(free_group(', '.join(y)))
C._schreier_free_group = grp_gens.pop(0)
C._schreier_generators = grp_gens
if homomorphism:
C._schreier_gen_elem = _gens
# replace all elements of P by, free group elements
for i, j in product(range(len(C.P)), range(len(C.A))):
# if equals "<identity>", replace by identity element
if C.P[i][j] == "<identity>":
C.P[i][j] = C._schreier_free_group.identity
elif isinstance(C.P[i][j], str):
r = C._schreier_generators[y.index(C.P[i][j])]
C.P[i][j] = r
beta = C.table[i][j]
C.P[beta][j + 1] = r**-1
def reidemeister_relators(C):
R = C.fp_group.relators
rels = [rewrite(C, coset, word) for word in R for coset in range(C.n)]
order_1_gens = {i for i in rels if len(i) == 1}
# remove all the order 1 generators from relators
rels = list(filter(lambda rel: rel not in order_1_gens, rels))
# replace order 1 generators by identity element in reidemeister relators
for i in range(len(rels)):
w = rels[i]
w = w.eliminate_words(order_1_gens, _all=True)
rels[i] = w
C._schreier_generators = [i for i in C._schreier_generators
if not (i in order_1_gens or i**-1 in order_1_gens)]
# Tietze transformation 1 i.e TT_1
# remove cyclic conjugate elements from relators
i = 0
while i < len(rels):
w = rels[i]
j = i + 1
while j < len(rels):
if w.is_cyclic_conjugate(rels[j]):
del rels[j]
else:
j += 1
i += 1
C._reidemeister_relators = rels
def rewrite(C, alpha, w):
"""
Parameters
==========
C: CosetTable
alpha: A live coset
w: A word in `A*`
Returns
=======
rho(tau(alpha), w)
Examples
========
>>> from sympy.combinatorics.fp_groups import FpGroup, CosetTable, define_schreier_generators, rewrite
>>> from sympy.combinatorics import free_group
>>> F, x, y = free_group("x, y")
>>> f = FpGroup(F, [x**2, y**3, (x*y)**6])
>>> C = CosetTable(f, [])
>>> C.table = [[1, 1, 2, 3], [0, 0, 4, 5], [4, 4, 3, 0], [5, 5, 0, 2], [2, 2, 5, 1], [3, 3, 1, 4]]
>>> C.p = [0, 1, 2, 3, 4, 5]
>>> define_schreier_generators(C)
>>> rewrite(C, 0, (x*y)**6)
x_4*y_2*x_3*x_1*x_2*y_4*x_5
"""
v = C._schreier_free_group.identity
for i in range(len(w)):
x_i = w[i]
v = v*C.P[alpha][C.A_dict[x_i]]
alpha = C.table[alpha][C.A_dict[x_i]]
return v
# Pg 350, section 2.5.2 from [2]
def elimination_technique_2(C):
"""
This technique eliminates one generator at a time. Heuristically this
seems superior in that we may select for elimination the generator with
shortest equivalent string at each stage.
>>> from sympy.combinatorics import free_group
>>> from sympy.combinatorics.fp_groups import FpGroup, coset_enumeration_r, \
reidemeister_relators, define_schreier_generators, elimination_technique_2
>>> F, x, y = free_group("x, y")
>>> f = FpGroup(F, [x**3, y**5, (x*y)**2]); H = [x*y, x**-1*y**-1*x*y*x]
>>> C = coset_enumeration_r(f, H)
>>> C.compress(); C.standardize()
>>> define_schreier_generators(C)
>>> reidemeister_relators(C)
>>> elimination_technique_2(C)
([y_1, y_2], [y_2**-3, y_2*y_1*y_2*y_1*y_2*y_1, y_1**2])
"""
rels = C._reidemeister_relators
rels.sort(reverse=True)
gens = C._schreier_generators
for i in range(len(gens) - 1, -1, -1):
rel = rels[i]
for j in range(len(gens) - 1, -1, -1):
gen = gens[j]
if rel.generator_count(gen) == 1:
k = rel.exponent_sum(gen)
gen_index = rel.index(gen**k)
bk = rel.subword(gen_index + 1, len(rel))
fw = rel.subword(0, gen_index)
rep_by = (bk*fw)**(-1*k)
del rels[i]; del gens[j]
for l in range(len(rels)):
rels[l] = rels[l].eliminate_word(gen, rep_by)
break
C._reidemeister_relators = rels
C._schreier_generators = gens
return C._schreier_generators, C._reidemeister_relators
def reidemeister_presentation(fp_grp, H, C=None, homomorphism=False):
"""
Parameters
==========
fp_group: A finitely presented group, an instance of FpGroup
H: A subgroup whose presentation is to be found, given as a list
of words in generators of `fp_grp`
homomorphism: When set to True, return a homomorphism from the subgroup
to the parent group
Examples
========
>>> from sympy.combinatorics import free_group
>>> from sympy.combinatorics.fp_groups import FpGroup, reidemeister_presentation
>>> F, x, y = free_group("x, y")
Example 5.6 Pg. 177 from [1]
>>> f = FpGroup(F, [x**3, y**5, (x*y)**2])
>>> H = [x*y, x**-1*y**-1*x*y*x]
>>> reidemeister_presentation(f, H)
((y_1, y_2), (y_1**2, y_2**3, y_2*y_1*y_2*y_1*y_2*y_1))
Example 5.8 Pg. 183 from [1]
>>> f = FpGroup(F, [x**3, y**3, (x*y)**3])
>>> H = [x*y, x*y**-1]
>>> reidemeister_presentation(f, H)
((x_0, y_0), (x_0**3, y_0**3, x_0*y_0*x_0*y_0*x_0*y_0))
Exercises Q2. Pg 187 from [1]
>>> f = FpGroup(F, [x**2*y**2, y**-1*x*y*x**-3])
>>> H = [x]
>>> reidemeister_presentation(f, H)
((x_0,), (x_0**4,))
Example 5.9 Pg. 183 from [1]
>>> f = FpGroup(F, [x**3*y**-3, (x*y)**3, (x*y**-1)**2])
>>> H = [x]
>>> reidemeister_presentation(f, H)
((x_0,), (x_0**6,))
"""
if not C:
C = coset_enumeration_r(fp_grp, H)
C.compress(); C.standardize()
define_schreier_generators(C, homomorphism=homomorphism)
reidemeister_relators(C)
gens, rels = C._schreier_generators, C._reidemeister_relators
gens, rels = simplify_presentation(gens, rels, change_gens=True)
C.schreier_generators = tuple(gens)
C.reidemeister_relators = tuple(rels)
if homomorphism:
_gens = []
for gen in gens:
_gens.append(C._schreier_gen_elem[str(gen)])
return C.schreier_generators, C.reidemeister_relators, _gens
return C.schreier_generators, C.reidemeister_relators
FpGroupElement = FreeGroupElement
PK ]ZZZ��P7� 7� " sympy/combinatorics/free_groups.pyfrom __future__ import annotations
from sympy.core import S
from sympy.core.expr import Expr
from sympy.core.symbol import Symbol, symbols as _symbols
from sympy.core.sympify import CantSympify
from sympy.printing.defaults import DefaultPrinting
from sympy.utilities import public
from sympy.utilities.iterables import flatten, is_sequence
from sympy.utilities.magic import pollute
from sympy.utilities.misc import as_int
@public
def free_group(symbols):
"""Construct a free group returning ``(FreeGroup, (f_0, f_1, ..., f_(n-1))``.
Parameters
==========
symbols : str, Symbol/Expr or sequence of str, Symbol/Expr (may be empty)
Examples
========
>>> from sympy.combinatorics import free_group
>>> F, x, y, z = free_group("x, y, z")
>>> F
<free group on the generators (x, y, z)>
>>> x**2*y**-1
x**2*y**-1
>>> type(_)
<class 'sympy.combinatorics.free_groups.FreeGroupElement'>
"""
_free_group = FreeGroup(symbols)
return (_free_group,) + tuple(_free_group.generators)
@public
def xfree_group(symbols):
"""Construct a free group returning ``(FreeGroup, (f_0, f_1, ..., f_(n-1)))``.
Parameters
==========
symbols : str, Symbol/Expr or sequence of str, Symbol/Expr (may be empty)
Examples
========
>>> from sympy.combinatorics.free_groups import xfree_group
>>> F, (x, y, z) = xfree_group("x, y, z")
>>> F
<free group on the generators (x, y, z)>
>>> y**2*x**-2*z**-1
y**2*x**-2*z**-1
>>> type(_)
<class 'sympy.combinatorics.free_groups.FreeGroupElement'>
"""
_free_group = FreeGroup(symbols)
return (_free_group, _free_group.generators)
@public
def vfree_group(symbols):
"""Construct a free group and inject ``f_0, f_1, ..., f_(n-1)`` as symbols
into the global namespace.
Parameters
==========
symbols : str, Symbol/Expr or sequence of str, Symbol/Expr (may be empty)
Examples
========
>>> from sympy.combinatorics.free_groups import vfree_group
>>> vfree_group("x, y, z")
<free group on the generators (x, y, z)>
>>> x**2*y**-2*z # noqa: F821
x**2*y**-2*z
>>> type(_)
<class 'sympy.combinatorics.free_groups.FreeGroupElement'>
"""
_free_group = FreeGroup(symbols)
pollute([sym.name for sym in _free_group.symbols], _free_group.generators)
return _free_group
def _parse_symbols(symbols):
if not symbols:
return ()
if isinstance(symbols, str):
return _symbols(symbols, seq=True)
elif isinstance(symbols, (Expr, FreeGroupElement)):
return (symbols,)
elif is_sequence(symbols):
if all(isinstance(s, str) for s in symbols):
return _symbols(symbols)
elif all(isinstance(s, Expr) for s in symbols):
return symbols
raise ValueError("The type of `symbols` must be one of the following: "
"a str, Symbol/Expr or a sequence of "
"one of these types")
##############################################################################
# FREE GROUP #
##############################################################################
_free_group_cache: dict[int, FreeGroup] = {}
class FreeGroup(DefaultPrinting):
"""
Free group with finite or infinite number of generators. Its input API
is that of a str, Symbol/Expr or a sequence of one of
these types (which may be empty)
See Also
========
sympy.polys.rings.PolyRing
References
==========
.. [1] https://www.gap-system.org/Manuals/doc/ref/chap37.html
.. [2] https://en.wikipedia.org/wiki/Free_group
"""
is_associative = True
is_group = True
is_FreeGroup = True
is_PermutationGroup = False
relators: list[Expr] = []
def __new__(cls, symbols):
symbols = tuple(_parse_symbols(symbols))
rank = len(symbols)
_hash = hash((cls.__name__, symbols, rank))
obj = _free_group_cache.get(_hash)
if obj is None:
obj = object.__new__(cls)
obj._hash = _hash
obj._rank = rank
# dtype method is used to create new instances of FreeGroupElement
obj.dtype = type("FreeGroupElement", (FreeGroupElement,), {"group": obj})
obj.symbols = symbols
obj.generators = obj._generators()
obj._gens_set = set(obj.generators)
for symbol, generator in zip(obj.symbols, obj.generators):
if isinstance(symbol, Symbol):
name = symbol.name
if hasattr(obj, name):
setattr(obj, name, generator)
_free_group_cache[_hash] = obj
return obj
def _generators(group):
"""Returns the generators of the FreeGroup.
Examples
========
>>> from sympy.combinatorics import free_group
>>> F, x, y, z = free_group("x, y, z")
>>> F.generators
(x, y, z)
"""
gens = []
for sym in group.symbols:
elm = ((sym, 1),)
gens.append(group.dtype(elm))
return tuple(gens)
def clone(self, symbols=None):
return self.__class__(symbols or self.symbols)
def __contains__(self, i):
"""Return True if ``i`` is contained in FreeGroup."""
if not isinstance(i, FreeGroupElement):
return False
group = i.group
return self == group
def __hash__(self):
return self._hash
def __len__(self):
return self.rank
def __str__(self):
if self.rank > 30:
str_form = "<free group with %s generators>" % self.rank
else:
str_form = "<free group on the generators "
gens = self.generators
str_form += str(gens) + ">"
return str_form
__repr__ = __str__
def __getitem__(self, index):
symbols = self.symbols[index]
return self.clone(symbols=symbols)
def __eq__(self, other):
"""No ``FreeGroup`` is equal to any "other" ``FreeGroup``.
"""
return self is other
def index(self, gen):
"""Return the index of the generator `gen` from ``(f_0, ..., f_(n-1))``.
Examples
========
>>> from sympy.combinatorics import free_group
>>> F, x, y = free_group("x, y")
>>> F.index(y)
1
>>> F.index(x)
0
"""
if isinstance(gen, self.dtype):
return self.generators.index(gen)
else:
raise ValueError("expected a generator of Free Group %s, got %s" % (self, gen))
def order(self):
"""Return the order of the free group.
Examples
========
>>> from sympy.combinatorics import free_group
>>> F, x, y = free_group("x, y")
>>> F.order()
oo
>>> free_group("")[0].order()
1
"""
if self.rank == 0:
return S.One
else:
return S.Infinity
@property
def elements(self):
"""
Return the elements of the free group.
Examples
========
>>> from sympy.combinatorics import free_group
>>> (z,) = free_group("")
>>> z.elements
{<identity>}
"""
if self.rank == 0:
# A set containing Identity element of `FreeGroup` self is returned
return {self.identity}
else:
raise ValueError("Group contains infinitely many elements"
", hence cannot be represented")
@property
def rank(self):
r"""
In group theory, the `rank` of a group `G`, denoted `G.rank`,
can refer to the smallest cardinality of a generating set
for G, that is
\operatorname{rank}(G)=\min\{ |X|: X\subseteq G, \left\langle X\right\rangle =G\}.
"""
return self._rank
@property
def is_abelian(self):
"""Returns if the group is Abelian.
Examples
========
>>> from sympy.combinatorics import free_group
>>> f, x, y, z = free_group("x y z")
>>> f.is_abelian
False
"""
return self.rank in (0, 1)
@property
def identity(self):
"""Returns the identity element of free group."""
return self.dtype()
def contains(self, g):
"""Tests if Free Group element ``g`` belong to self, ``G``.
In mathematical terms any linear combination of generators
of a Free Group is contained in it.
Examples
========
>>> from sympy.combinatorics import free_group
>>> f, x, y, z = free_group("x y z")
>>> f.contains(x**3*y**2)
True
"""
if not isinstance(g, FreeGroupElement):
return False
elif self != g.group:
return False
else:
return True
def center(self):
"""Returns the center of the free group `self`."""
return {self.identity}
############################################################################
# FreeGroupElement #
############################################################################
class FreeGroupElement(CantSympify, DefaultPrinting, tuple):
"""Used to create elements of FreeGroup. It cannot be used directly to
create a free group element. It is called by the `dtype` method of the
`FreeGroup` class.
"""
is_assoc_word = True
def new(self, init):
return self.__class__(init)
_hash = None
def __hash__(self):
_hash = self._hash
if _hash is None:
self._hash = _hash = hash((self.group, frozenset(tuple(self))))
return _hash
def copy(self):
return self.new(self)
@property
def is_identity(self):
if self.array_form == ():
return True
else:
return False
@property
def array_form(self):
"""
SymPy provides two different internal kinds of representation
of associative words. The first one is called the `array_form`
which is a tuple containing `tuples` as its elements, where the
size of each tuple is two. At the first position the tuple
contains the `symbol-generator`, while at the second position
of tuple contains the exponent of that generator at the position.
Since elements (i.e. words) do not commute, the indexing of tuple
makes that property to stay.
The structure in ``array_form`` of ``FreeGroupElement`` is of form:
``( ( symbol_of_gen, exponent ), ( , ), ... ( , ) )``
Examples
========
>>> from sympy.combinatorics import free_group
>>> f, x, y, z = free_group("x y z")
>>> (x*z).array_form
((x, 1), (z, 1))
>>> (x**2*z*y*x**2).array_form
((x, 2), (z, 1), (y, 1), (x, 2))
See Also
========
letter_repr
"""
return tuple(self)
@property
def letter_form(self):
"""
The letter representation of a ``FreeGroupElement`` is a tuple
of generator symbols, with each entry corresponding to a group
generator. Inverses of the generators are represented by
negative generator symbols.
Examples
========
>>> from sympy.combinatorics import free_group
>>> f, a, b, c, d = free_group("a b c d")
>>> (a**3).letter_form
(a, a, a)
>>> (a**2*d**-2*a*b**-4).letter_form
(a, a, -d, -d, a, -b, -b, -b, -b)
>>> (a**-2*b**3*d).letter_form
(-a, -a, b, b, b, d)
See Also
========
array_form
"""
return tuple(flatten([(i,)*j if j > 0 else (-i,)*(-j)
for i, j in self.array_form]))
def __getitem__(self, i):
group = self.group
r = self.letter_form[i]
if r.is_Symbol:
return group.dtype(((r, 1),))
else:
return group.dtype(((-r, -1),))
def index(self, gen):
if len(gen) != 1:
raise ValueError()
return (self.letter_form).index(gen.letter_form[0])
@property
def letter_form_elm(self):
"""
"""
group = self.group
r = self.letter_form
return [group.dtype(((elm,1),)) if elm.is_Symbol \
else group.dtype(((-elm,-1),)) for elm in r]
@property
def ext_rep(self):
"""This is called the External Representation of ``FreeGroupElement``
"""
return tuple(flatten(self.array_form))
def __contains__(self, gen):
return gen.array_form[0][0] in tuple([r[0] for r in self.array_form])
def __str__(self):
if self.is_identity:
return "<identity>"
str_form = ""
array_form = self.array_form
for i in range(len(array_form)):
if i == len(array_form) - 1:
if array_form[i][1] == 1:
str_form += str(array_form[i][0])
else:
str_form += str(array_form[i][0]) + \
"**" + str(array_form[i][1])
else:
if array_form[i][1] == 1:
str_form += str(array_form[i][0]) + "*"
else:
str_form += str(array_form[i][0]) + \
"**" + str(array_form[i][1]) + "*"
return str_form
__repr__ = __str__
def __pow__(self, n):
n = as_int(n)
result = self.group.identity
if n == 0:
return result
if n < 0:
n = -n
x = self.inverse()
else:
x = self
while True:
if n % 2:
result *= x
n >>= 1
if not n:
break
x *= x
return result
def __mul__(self, other):
"""Returns the product of elements belonging to the same ``FreeGroup``.
Examples
========
>>> from sympy.combinatorics import free_group
>>> f, x, y, z = free_group("x y z")
>>> x*y**2*y**-4
x*y**-2
>>> z*y**-2
z*y**-2
>>> x**2*y*y**-1*x**-2
<identity>
"""
group = self.group
if not isinstance(other, group.dtype):
raise TypeError("only FreeGroup elements of same FreeGroup can "
"be multiplied")
if self.is_identity:
return other
if other.is_identity:
return self
r = list(self.array_form + other.array_form)
zero_mul_simp(r, len(self.array_form) - 1)
return group.dtype(tuple(r))
def __truediv__(self, other):
group = self.group
if not isinstance(other, group.dtype):
raise TypeError("only FreeGroup elements of same FreeGroup can "
"be multiplied")
return self*(other.inverse())
def __rtruediv__(self, other):
group = self.group
if not isinstance(other, group.dtype):
raise TypeError("only FreeGroup elements of same FreeGroup can "
"be multiplied")
return other*(self.inverse())
def __add__(self, other):
return NotImplemented
def inverse(self):
"""
Returns the inverse of a ``FreeGroupElement`` element
Examples
========
>>> from sympy.combinatorics import free_group
>>> f, x, y, z = free_group("x y z")
>>> x.inverse()
x**-1
>>> (x*y).inverse()
y**-1*x**-1
"""
group = self.group
r = tuple([(i, -j) for i, j in self.array_form[::-1]])
return group.dtype(r)
def order(self):
"""Find the order of a ``FreeGroupElement``.
Examples
========
>>> from sympy.combinatorics import free_group
>>> f, x, y = free_group("x y")
>>> (x**2*y*y**-1*x**-2).order()
1
"""
if self.is_identity:
return S.One
else:
return S.Infinity
def commutator(self, other):
"""
Return the commutator of `self` and `x`: ``~x*~self*x*self``
"""
group = self.group
if not isinstance(other, group.dtype):
raise ValueError("commutator of only FreeGroupElement of the same "
"FreeGroup exists")
else:
return self.inverse()*other.inverse()*self*other
def eliminate_words(self, words, _all=False, inverse=True):
'''
Replace each subword from the dictionary `words` by words[subword].
If words is a list, replace the words by the identity.
'''
again = True
new = self
if isinstance(words, dict):
while again:
again = False
for sub in words:
prev = new
new = new.eliminate_word(sub, words[sub], _all=_all, inverse=inverse)
if new != prev:
again = True
else:
while again:
again = False
for sub in words:
prev = new
new = new.eliminate_word(sub, _all=_all, inverse=inverse)
if new != prev:
again = True
return new
def eliminate_word(self, gen, by=None, _all=False, inverse=True):
"""
For an associative word `self`, a subword `gen`, and an associative
word `by` (identity by default), return the associative word obtained by
replacing each occurrence of `gen` in `self` by `by`. If `_all = True`,
the occurrences of `gen` that may appear after the first substitution will
also be replaced and so on until no occurrences are found. This might not
always terminate (e.g. `(x).eliminate_word(x, x**2, _all=True)`).
Examples
========
>>> from sympy.combinatorics import free_group
>>> f, x, y = free_group("x y")
>>> w = x**5*y*x**2*y**-4*x
>>> w.eliminate_word( x, x**2 )
x**10*y*x**4*y**-4*x**2
>>> w.eliminate_word( x, y**-1 )
y**-11
>>> w.eliminate_word(x**5)
y*x**2*y**-4*x
>>> w.eliminate_word(x*y, y)
x**4*y*x**2*y**-4*x
See Also
========
substituted_word
"""
if by is None:
by = self.group.identity
if self.is_independent(gen) or gen == by:
return self
if gen == self:
return by
if gen**-1 == by:
_all = False
word = self
l = len(gen)
try:
i = word.subword_index(gen)
k = 1
except ValueError:
if not inverse:
return word
try:
i = word.subword_index(gen**-1)
k = -1
except ValueError:
return word
word = word.subword(0, i)*by**k*word.subword(i+l, len(word)).eliminate_word(gen, by)
if _all:
return word.eliminate_word(gen, by, _all=True, inverse=inverse)
else:
return word
def __len__(self):
"""
For an associative word `self`, returns the number of letters in it.
Examples
========
>>> from sympy.combinatorics import free_group
>>> f, a, b = free_group("a b")
>>> w = a**5*b*a**2*b**-4*a
>>> len(w)
13
>>> len(a**17)
17
>>> len(w**0)
0
"""
return sum(abs(j) for (i, j) in self)
def __eq__(self, other):
"""
Two associative words are equal if they are words over the
same alphabet and if they are sequences of the same letters.
This is equivalent to saying that the external representations
of the words are equal.
There is no "universal" empty word, every alphabet has its own
empty word.
Examples
========
>>> from sympy.combinatorics import free_group
>>> f, swapnil0, swapnil1 = free_group("swapnil0 swapnil1")
>>> f
<free group on the generators (swapnil0, swapnil1)>
>>> g, swap0, swap1 = free_group("swap0 swap1")
>>> g
<free group on the generators (swap0, swap1)>
>>> swapnil0 == swapnil1
False
>>> swapnil0*swapnil1 == swapnil1/swapnil1*swapnil0*swapnil1
True
>>> swapnil0*swapnil1 == swapnil1*swapnil0
False
>>> swapnil1**0 == swap0**0
False
"""
group = self.group
if not isinstance(other, group.dtype):
return False
return tuple.__eq__(self, other)
def __lt__(self, other):
"""
The ordering of associative words is defined by length and
lexicography (this ordering is called short-lex ordering), that
is, shorter words are smaller than longer words, and words of the
same length are compared w.r.t. the lexicographical ordering induced
by the ordering of generators. Generators are sorted according
to the order in which they were created. If the generators are
invertible then each generator `g` is larger than its inverse `g^{-1}`,
and `g^{-1}` is larger than every generator that is smaller than `g`.
Examples
========
>>> from sympy.combinatorics import free_group
>>> f, a, b = free_group("a b")
>>> b < a
False
>>> a < a.inverse()
False
"""
group = self.group
if not isinstance(other, group.dtype):
raise TypeError("only FreeGroup elements of same FreeGroup can "
"be compared")
l = len(self)
m = len(other)
# implement lenlex order
if l < m:
return True
elif l > m:
return False
for i in range(l):
a = self[i].array_form[0]
b = other[i].array_form[0]
p = group.symbols.index(a[0])
q = group.symbols.index(b[0])
if p < q:
return True
elif p > q:
return False
elif a[1] < b[1]:
return True
elif a[1] > b[1]:
return False
return False
def __le__(self, other):
return (self == other or self < other)
def __gt__(self, other):
"""
Examples
========
>>> from sympy.combinatorics import free_group
>>> f, x, y, z = free_group("x y z")
>>> y**2 > x**2
True
>>> y*z > z*y
False
>>> x > x.inverse()
True
"""
group = self.group
if not isinstance(other, group.dtype):
raise TypeError("only FreeGroup elements of same FreeGroup can "
"be compared")
return not self <= other
def __ge__(self, other):
return not self < other
def exponent_sum(self, gen):
"""
For an associative word `self` and a generator or inverse of generator
`gen`, ``exponent_sum`` returns the number of times `gen` appears in
`self` minus the number of times its inverse appears in `self`. If
neither `gen` nor its inverse occur in `self` then 0 is returned.
Examples
========
>>> from sympy.combinatorics import free_group
>>> F, x, y = free_group("x, y")
>>> w = x**2*y**3
>>> w.exponent_sum(x)
2
>>> w.exponent_sum(x**-1)
-2
>>> w = x**2*y**4*x**-3
>>> w.exponent_sum(x)
-1
See Also
========
generator_count
"""
if len(gen) != 1:
raise ValueError("gen must be a generator or inverse of a generator")
s = gen.array_form[0]
return s[1]*sum(i[1] for i in self.array_form if i[0] == s[0])
def generator_count(self, gen):
"""
For an associative word `self` and a generator `gen`,
``generator_count`` returns the multiplicity of generator
`gen` in `self`.
Examples
========
>>> from sympy.combinatorics import free_group
>>> F, x, y = free_group("x, y")
>>> w = x**2*y**3
>>> w.generator_count(x)
2
>>> w = x**2*y**4*x**-3
>>> w.generator_count(x)
5
See Also
========
exponent_sum
"""
if len(gen) != 1 or gen.array_form[0][1] < 0:
raise ValueError("gen must be a generator")
s = gen.array_form[0]
return s[1]*sum(abs(i[1]) for i in self.array_form if i[0] == s[0])
def subword(self, from_i, to_j, strict=True):
"""
For an associative word `self` and two positive integers `from_i` and
`to_j`, `subword` returns the subword of `self` that begins at position
`from_i` and ends at `to_j - 1`, indexing is done with origin 0.
Examples
========
>>> from sympy.combinatorics import free_group
>>> f, a, b = free_group("a b")
>>> w = a**5*b*a**2*b**-4*a
>>> w.subword(2, 6)
a**3*b
"""
group = self.group
if not strict:
from_i = max(from_i, 0)
to_j = min(len(self), to_j)
if from_i < 0 or to_j > len(self):
raise ValueError("`from_i`, `to_j` must be positive and no greater than "
"the length of associative word")
if to_j <= from_i:
return group.identity
else:
letter_form = self.letter_form[from_i: to_j]
array_form = letter_form_to_array_form(letter_form, group)
return group.dtype(array_form)
def subword_index(self, word, start = 0):
'''
Find the index of `word` in `self`.
Examples
========
>>> from sympy.combinatorics import free_group
>>> f, a, b = free_group("a b")
>>> w = a**2*b*a*b**3
>>> w.subword_index(a*b*a*b)
1
'''
l = len(word)
self_lf = self.letter_form
word_lf = word.letter_form
index = None
for i in range(start,len(self_lf)-l+1):
if self_lf[i:i+l] == word_lf:
index = i
break
if index is not None:
return index
else:
raise ValueError("The given word is not a subword of self")
def is_dependent(self, word):
"""
Examples
========
>>> from sympy.combinatorics import free_group
>>> F, x, y = free_group("x, y")
>>> (x**4*y**-3).is_dependent(x**4*y**-2)
True
>>> (x**2*y**-1).is_dependent(x*y)
False
>>> (x*y**2*x*y**2).is_dependent(x*y**2)
True
>>> (x**12).is_dependent(x**-4)
True
See Also
========
is_independent
"""
try:
return self.subword_index(word) is not None
except ValueError:
pass
try:
return self.subword_index(word**-1) is not None
except ValueError:
return False
def is_independent(self, word):
"""
See Also
========
is_dependent
"""
return not self.is_dependent(word)
def contains_generators(self):
"""
Examples
========
>>> from sympy.combinatorics import free_group
>>> F, x, y, z = free_group("x, y, z")
>>> (x**2*y**-1).contains_generators()
{x, y}
>>> (x**3*z).contains_generators()
{x, z}
"""
group = self.group
gens = {group.dtype(((syllable[0], 1),)) for syllable in self.array_form}
return gens
def cyclic_subword(self, from_i, to_j):
group = self.group
l = len(self)
letter_form = self.letter_form
period1 = int(from_i/l)
if from_i >= l:
from_i -= l*period1
to_j -= l*period1
diff = to_j - from_i
word = letter_form[from_i: to_j]
period2 = int(to_j/l) - 1
word += letter_form*period2 + letter_form[:diff-l+from_i-l*period2]
word = letter_form_to_array_form(word, group)
return group.dtype(word)
def cyclic_conjugates(self):
"""Returns a words which are cyclic to the word `self`.
Examples
========
>>> from sympy.combinatorics import free_group
>>> F, x, y = free_group("x, y")
>>> w = x*y*x*y*x
>>> w.cyclic_conjugates()
{x*y*x**2*y, x**2*y*x*y, y*x*y*x**2, y*x**2*y*x, x*y*x*y*x}
>>> s = x*y*x**2*y*x
>>> s.cyclic_conjugates()
{x**2*y*x**2*y, y*x**2*y*x**2, x*y*x**2*y*x}
References
==========
.. [1] https://planetmath.org/cyclicpermutation
"""
return {self.cyclic_subword(i, i+len(self)) for i in range(len(self))}
def is_cyclic_conjugate(self, w):
"""
Checks whether words ``self``, ``w`` are cyclic conjugates.
Examples
========
>>> from sympy.combinatorics import free_group
>>> F, x, y = free_group("x, y")
>>> w1 = x**2*y**5
>>> w2 = x*y**5*x
>>> w1.is_cyclic_conjugate(w2)
True
>>> w3 = x**-1*y**5*x**-1
>>> w3.is_cyclic_conjugate(w2)
False
"""
l1 = len(self)
l2 = len(w)
if l1 != l2:
return False
w1 = self.identity_cyclic_reduction()
w2 = w.identity_cyclic_reduction()
letter1 = w1.letter_form
letter2 = w2.letter_form
str1 = ' '.join(map(str, letter1))
str2 = ' '.join(map(str, letter2))
if len(str1) != len(str2):
return False
return str1 in str2 + ' ' + str2
def number_syllables(self):
"""Returns the number of syllables of the associative word `self`.
Examples
========
>>> from sympy.combinatorics import free_group
>>> f, swapnil0, swapnil1 = free_group("swapnil0 swapnil1")
>>> (swapnil1**3*swapnil0*swapnil1**-1).number_syllables()
3
"""
return len(self.array_form)
def exponent_syllable(self, i):
"""
Returns the exponent of the `i`-th syllable of the associative word
`self`.
Examples
========
>>> from sympy.combinatorics import free_group
>>> f, a, b = free_group("a b")
>>> w = a**5*b*a**2*b**-4*a
>>> w.exponent_syllable( 2 )
2
"""
return self.array_form[i][1]
def generator_syllable(self, i):
"""
Returns the symbol of the generator that is involved in the
i-th syllable of the associative word `self`.
Examples
========
>>> from sympy.combinatorics import free_group
>>> f, a, b = free_group("a b")
>>> w = a**5*b*a**2*b**-4*a
>>> w.generator_syllable( 3 )
b
"""
return self.array_form[i][0]
def sub_syllables(self, from_i, to_j):
"""
`sub_syllables` returns the subword of the associative word `self` that
consists of syllables from positions `from_to` to `to_j`, where
`from_to` and `to_j` must be positive integers and indexing is done
with origin 0.
Examples
========
>>> from sympy.combinatorics import free_group
>>> f, a, b = free_group("a, b")
>>> w = a**5*b*a**2*b**-4*a
>>> w.sub_syllables(1, 2)
b
>>> w.sub_syllables(3, 3)
<identity>
"""
if not isinstance(from_i, int) or not isinstance(to_j, int):
raise ValueError("both arguments should be integers")
group = self.group
if to_j <= from_i:
return group.identity
else:
r = tuple(self.array_form[from_i: to_j])
return group.dtype(r)
def substituted_word(self, from_i, to_j, by):
"""
Returns the associative word obtained by replacing the subword of
`self` that begins at position `from_i` and ends at position `to_j - 1`
by the associative word `by`. `from_i` and `to_j` must be positive
integers, indexing is done with origin 0. In other words,
`w.substituted_word(w, from_i, to_j, by)` is the product of the three
words: `w.subword(0, from_i)`, `by`, and
`w.subword(to_j len(w))`.
See Also
========
eliminate_word
"""
lw = len(self)
if from_i >= to_j or from_i > lw or to_j > lw:
raise ValueError("values should be within bounds")
# otherwise there are four possibilities
# first if from=1 and to=lw then
if from_i == 0 and to_j == lw:
return by
elif from_i == 0: # second if from_i=1 (and to_j < lw) then
return by*self.subword(to_j, lw)
elif to_j == lw: # third if to_j=1 (and from_i > 1) then
return self.subword(0, from_i)*by
else: # finally
return self.subword(0, from_i)*by*self.subword(to_j, lw)
def is_cyclically_reduced(self):
r"""Returns whether the word is cyclically reduced or not.
A word is cyclically reduced if by forming the cycle of the
word, the word is not reduced, i.e a word w = `a_1 ... a_n`
is called cyclically reduced if `a_1 \ne a_n^{-1}`.
Examples
========
>>> from sympy.combinatorics import free_group
>>> F, x, y = free_group("x, y")
>>> (x**2*y**-1*x**-1).is_cyclically_reduced()
False
>>> (y*x**2*y**2).is_cyclically_reduced()
True
"""
if not self:
return True
return self[0] != self[-1]**-1
def identity_cyclic_reduction(self):
"""Return a unique cyclically reduced version of the word.
Examples
========
>>> from sympy.combinatorics import free_group
>>> F, x, y = free_group("x, y")
>>> (x**2*y**2*x**-1).identity_cyclic_reduction()
x*y**2
>>> (x**-3*y**-1*x**5).identity_cyclic_reduction()
x**2*y**-1
References
==========
.. [1] https://planetmath.org/cyclicallyreduced
"""
word = self.copy()
group = self.group
while not word.is_cyclically_reduced():
exp1 = word.exponent_syllable(0)
exp2 = word.exponent_syllable(-1)
r = exp1 + exp2
if r == 0:
rep = word.array_form[1: word.number_syllables() - 1]
else:
rep = ((word.generator_syllable(0), exp1 + exp2),) + \
word.array_form[1: word.number_syllables() - 1]
word = group.dtype(rep)
return word
def cyclic_reduction(self, removed=False):
"""Return a cyclically reduced version of the word. Unlike
`identity_cyclic_reduction`, this will not cyclically permute
the reduced word - just remove the "unreduced" bits on either
side of it. Compare the examples with those of
`identity_cyclic_reduction`.
When `removed` is `True`, return a tuple `(word, r)` where
self `r` is such that before the reduction the word was either
`r*word*r**-1`.
Examples
========
>>> from sympy.combinatorics import free_group
>>> F, x, y = free_group("x, y")
>>> (x**2*y**2*x**-1).cyclic_reduction()
x*y**2
>>> (x**-3*y**-1*x**5).cyclic_reduction()
y**-1*x**2
>>> (x**-3*y**-1*x**5).cyclic_reduction(removed=True)
(y**-1*x**2, x**-3)
"""
word = self.copy()
g = self.group.identity
while not word.is_cyclically_reduced():
exp1 = abs(word.exponent_syllable(0))
exp2 = abs(word.exponent_syllable(-1))
exp = min(exp1, exp2)
start = word[0]**abs(exp)
end = word[-1]**abs(exp)
word = start**-1*word*end**-1
g = g*start
if removed:
return word, g
return word
def power_of(self, other):
'''
Check if `self == other**n` for some integer n.
Examples
========
>>> from sympy.combinatorics import free_group
>>> F, x, y = free_group("x, y")
>>> ((x*y)**2).power_of(x*y)
True
>>> (x**-3*y**-2*x**3).power_of(x**-3*y*x**3)
True
'''
if self.is_identity:
return True
l = len(other)
if l == 1:
# self has to be a power of one generator
gens = self.contains_generators()
s = other in gens or other**-1 in gens
return len(gens) == 1 and s
# if self is not cyclically reduced and it is a power of other,
# other isn't cyclically reduced and the parts removed during
# their reduction must be equal
reduced, r1 = self.cyclic_reduction(removed=True)
if not r1.is_identity:
other, r2 = other.cyclic_reduction(removed=True)
if r1 == r2:
return reduced.power_of(other)
return False
if len(self) < l or len(self) % l:
return False
prefix = self.subword(0, l)
if prefix == other or prefix**-1 == other:
rest = self.subword(l, len(self))
return rest.power_of(other)
return False
def letter_form_to_array_form(array_form, group):
"""
This method converts a list given with possible repetitions of elements in
it. It returns a new list such that repetitions of consecutive elements is
removed and replace with a tuple element of size two such that the first
index contains `value` and the second index contains the number of
consecutive repetitions of `value`.
"""
a = list(array_form[:])
new_array = []
n = 1
symbols = group.symbols
for i in range(len(a)):
if i == len(a) - 1:
if a[i] == a[i - 1]:
if (-a[i]) in symbols:
new_array.append((-a[i], -n))
else:
new_array.append((a[i], n))
else:
if (-a[i]) in symbols:
new_array.append((-a[i], -1))
else:
new_array.append((a[i], 1))
return new_array
elif a[i] == a[i + 1]:
n += 1
else:
if (-a[i]) in symbols:
new_array.append((-a[i], -n))
else:
new_array.append((a[i], n))
n = 1
def zero_mul_simp(l, index):
"""Used to combine two reduced words."""
while index >=0 and index < len(l) - 1 and l[index][0] == l[index + 1][0]:
exp = l[index][1] + l[index + 1][1]
base = l[index][0]
l[index] = (base, exp)
del l[index + 1]
if l[index][1] == 0:
del l[index]
index -= 1
PK ]ZZZH(~�E �E sympy/combinatorics/galois.pyr"""
Construct transitive subgroups of symmetric groups, useful in Galois theory.
Besides constructing instances of the :py:class:`~.PermutationGroup` class to
represent the transitive subgroups of $S_n$ for small $n$, this module provides
*names* for these groups.
In some applications, it may be preferable to know the name of a group,
rather than receive an instance of the :py:class:`~.PermutationGroup`
class, and then have to do extra work to determine which group it is, by
checking various properties.
Names are instances of ``Enum`` classes defined in this module. With a name in
hand, the name's ``get_perm_group`` method can then be used to retrieve a
:py:class:`~.PermutationGroup`.
The names used for groups in this module are taken from [1].
References
==========
.. [1] Cohen, H. *A Course in Computational Algebraic Number Theory*.
"""
from collections import defaultdict
from enum import Enum
import itertools
from sympy.combinatorics.named_groups import (
SymmetricGroup, AlternatingGroup, CyclicGroup, DihedralGroup,
set_symmetric_group_properties, set_alternating_group_properties,
)
from sympy.combinatorics.perm_groups import PermutationGroup
from sympy.combinatorics.permutations import Permutation
class S1TransitiveSubgroups(Enum):
"""
Names for the transitive subgroups of S1.
"""
S1 = "S1"
def get_perm_group(self):
return SymmetricGroup(1)
class S2TransitiveSubgroups(Enum):
"""
Names for the transitive subgroups of S2.
"""
S2 = "S2"
def get_perm_group(self):
return SymmetricGroup(2)
class S3TransitiveSubgroups(Enum):
"""
Names for the transitive subgroups of S3.
"""
A3 = "A3"
S3 = "S3"
def get_perm_group(self):
if self == S3TransitiveSubgroups.A3:
return AlternatingGroup(3)
elif self == S3TransitiveSubgroups.S3:
return SymmetricGroup(3)
class S4TransitiveSubgroups(Enum):
"""
Names for the transitive subgroups of S4.
"""
C4 = "C4"
V = "V"
D4 = "D4"
A4 = "A4"
S4 = "S4"
def get_perm_group(self):
if self == S4TransitiveSubgroups.C4:
return CyclicGroup(4)
elif self == S4TransitiveSubgroups.V:
return four_group()
elif self == S4TransitiveSubgroups.D4:
return DihedralGroup(4)
elif self == S4TransitiveSubgroups.A4:
return AlternatingGroup(4)
elif self == S4TransitiveSubgroups.S4:
return SymmetricGroup(4)
class S5TransitiveSubgroups(Enum):
"""
Names for the transitive subgroups of S5.
"""
C5 = "C5"
D5 = "D5"
M20 = "M20"
A5 = "A5"
S5 = "S5"
def get_perm_group(self):
if self == S5TransitiveSubgroups.C5:
return CyclicGroup(5)
elif self == S5TransitiveSubgroups.D5:
return DihedralGroup(5)
elif self == S5TransitiveSubgroups.M20:
return M20()
elif self == S5TransitiveSubgroups.A5:
return AlternatingGroup(5)
elif self == S5TransitiveSubgroups.S5:
return SymmetricGroup(5)
class S6TransitiveSubgroups(Enum):
"""
Names for the transitive subgroups of S6.
"""
C6 = "C6"
S3 = "S3"
D6 = "D6"
A4 = "A4"
G18 = "G18"
A4xC2 = "A4 x C2"
S4m = "S4-"
S4p = "S4+"
G36m = "G36-"
G36p = "G36+"
S4xC2 = "S4 x C2"
PSL2F5 = "PSL2(F5)"
G72 = "G72"
PGL2F5 = "PGL2(F5)"
A6 = "A6"
S6 = "S6"
def get_perm_group(self):
if self == S6TransitiveSubgroups.C6:
return CyclicGroup(6)
elif self == S6TransitiveSubgroups.S3:
return S3_in_S6()
elif self == S6TransitiveSubgroups.D6:
return DihedralGroup(6)
elif self == S6TransitiveSubgroups.A4:
return A4_in_S6()
elif self == S6TransitiveSubgroups.G18:
return G18()
elif self == S6TransitiveSubgroups.A4xC2:
return A4xC2()
elif self == S6TransitiveSubgroups.S4m:
return S4m()
elif self == S6TransitiveSubgroups.S4p:
return S4p()
elif self == S6TransitiveSubgroups.G36m:
return G36m()
elif self == S6TransitiveSubgroups.G36p:
return G36p()
elif self == S6TransitiveSubgroups.S4xC2:
return S4xC2()
elif self == S6TransitiveSubgroups.PSL2F5:
return PSL2F5()
elif self == S6TransitiveSubgroups.G72:
return G72()
elif self == S6TransitiveSubgroups.PGL2F5:
return PGL2F5()
elif self == S6TransitiveSubgroups.A6:
return AlternatingGroup(6)
elif self == S6TransitiveSubgroups.S6:
return SymmetricGroup(6)
def four_group():
"""
Return a representation of the Klein four-group as a transitive subgroup
of S4.
"""
return PermutationGroup(
Permutation(0, 1)(2, 3),
Permutation(0, 2)(1, 3)
)
def M20():
"""
Return a representation of the metacyclic group M20, a transitive subgroup
of S5 that is one of the possible Galois groups for polys of degree 5.
Notes
=====
See [1], Page 323.
"""
G = PermutationGroup(Permutation(0, 1, 2, 3, 4), Permutation(1, 2, 4, 3))
G._degree = 5
G._order = 20
G._is_transitive = True
G._is_sym = False
G._is_alt = False
G._is_cyclic = False
G._is_dihedral = False
return G
def S3_in_S6():
"""
Return a representation of S3 as a transitive subgroup of S6.
Notes
=====
The representation is found by viewing the group as the symmetries of a
triangular prism.
"""
G = PermutationGroup(Permutation(0, 1, 2)(3, 4, 5), Permutation(0, 3)(2, 4)(1, 5))
set_symmetric_group_properties(G, 3, 6)
return G
def A4_in_S6():
"""
Return a representation of A4 as a transitive subgroup of S6.
Notes
=====
This was computed using :py:func:`~.find_transitive_subgroups_of_S6`.
"""
G = PermutationGroup(Permutation(0, 4, 5)(1, 3, 2), Permutation(0, 1, 2)(3, 5, 4))
set_alternating_group_properties(G, 4, 6)
return G
def S4m():
"""
Return a representation of the S4- transitive subgroup of S6.
Notes
=====
This was computed using :py:func:`~.find_transitive_subgroups_of_S6`.
"""
G = PermutationGroup(Permutation(1, 4, 5, 3), Permutation(0, 4)(1, 5)(2, 3))
set_symmetric_group_properties(G, 4, 6)
return G
def S4p():
"""
Return a representation of the S4+ transitive subgroup of S6.
Notes
=====
This was computed using :py:func:`~.find_transitive_subgroups_of_S6`.
"""
G = PermutationGroup(Permutation(0, 2, 4, 1)(3, 5), Permutation(0, 3)(4, 5))
set_symmetric_group_properties(G, 4, 6)
return G
def A4xC2():
"""
Return a representation of the (A4 x C2) transitive subgroup of S6.
Notes
=====
This was computed using :py:func:`~.find_transitive_subgroups_of_S6`.
"""
return PermutationGroup(
Permutation(0, 4, 5)(1, 3, 2), Permutation(0, 1, 2)(3, 5, 4),
Permutation(5)(2, 4))
def S4xC2():
"""
Return a representation of the (S4 x C2) transitive subgroup of S6.
Notes
=====
This was computed using :py:func:`~.find_transitive_subgroups_of_S6`.
"""
return PermutationGroup(
Permutation(1, 4, 5, 3), Permutation(0, 4)(1, 5)(2, 3),
Permutation(1, 4)(3, 5))
def G18():
"""
Return a representation of the group G18, a transitive subgroup of S6
isomorphic to the semidirect product of C3^2 with C2.
Notes
=====
This was computed using :py:func:`~.find_transitive_subgroups_of_S6`.
"""
return PermutationGroup(
Permutation(5)(0, 1, 2), Permutation(3, 4, 5),
Permutation(0, 4)(1, 5)(2, 3))
def G36m():
"""
Return a representation of the group G36-, a transitive subgroup of S6
isomorphic to the semidirect product of C3^2 with C2^2.
Notes
=====
This was computed using :py:func:`~.find_transitive_subgroups_of_S6`.
"""
return PermutationGroup(
Permutation(5)(0, 1, 2), Permutation(3, 4, 5),
Permutation(1, 2)(3, 5), Permutation(0, 4)(1, 5)(2, 3))
def G36p():
"""
Return a representation of the group G36+, a transitive subgroup of S6
isomorphic to the semidirect product of C3^2 with C4.
Notes
=====
This was computed using :py:func:`~.find_transitive_subgroups_of_S6`.
"""
return PermutationGroup(
Permutation(5)(0, 1, 2), Permutation(3, 4, 5),
Permutation(0, 5, 2, 3)(1, 4))
def G72():
"""
Return a representation of the group G72, a transitive subgroup of S6
isomorphic to the semidirect product of C3^2 with D4.
Notes
=====
See [1], Page 325.
"""
return PermutationGroup(
Permutation(5)(0, 1, 2),
Permutation(0, 4, 1, 3)(2, 5), Permutation(0, 3)(1, 4)(2, 5))
def PSL2F5():
r"""
Return a representation of the group $PSL_2(\mathbb{F}_5)$, as a transitive
subgroup of S6, isomorphic to $A_5$.
Notes
=====
This was computed using :py:func:`~.find_transitive_subgroups_of_S6`.
"""
G = PermutationGroup(
Permutation(0, 4, 5)(1, 3, 2), Permutation(0, 4, 3, 1, 5))
set_alternating_group_properties(G, 5, 6)
return G
def PGL2F5():
r"""
Return a representation of the group $PGL_2(\mathbb{F}_5)$, as a transitive
subgroup of S6, isomorphic to $S_5$.
Notes
=====
See [1], Page 325.
"""
G = PermutationGroup(
Permutation(0, 1, 2, 3, 4), Permutation(0, 5)(1, 2)(3, 4))
set_symmetric_group_properties(G, 5, 6)
return G
def find_transitive_subgroups_of_S6(*targets, print_report=False):
r"""
Search for certain transitive subgroups of $S_6$.
The symmetric group $S_6$ has 16 different transitive subgroups, up to
conjugacy. Some are more easily constructed than others. For example, the
dihedral group $D_6$ is immediately found, but it is not at all obvious how
to realize $S_4$ or $S_5$ *transitively* within $S_6$.
In some cases there are well-known constructions that can be used. For
example, $S_5$ is isomorphic to $PGL_2(\mathbb{F}_5)$, which acts in a
natural way on the projective line $P^1(\mathbb{F}_5)$, a set of order 6.
In absence of such special constructions however, we can simply search for
generators. For example, transitive instances of $A_4$ and $S_4$ can be
found within $S_6$ in this way.
Once we are engaged in such searches, it may then be easier (if less
elegant) to find even those groups like $S_5$ that do have special
constructions, by mere search.
This function locates generators for transitive instances in $S_6$ of the
following subgroups:
* $A_4$
* $S_4^-$ ($S_4$ not contained within $A_6$)
* $S_4^+$ ($S_4$ contained within $A_6$)
* $A_4 \times C_2$
* $S_4 \times C_2$
* $G_{18} = C_3^2 \rtimes C_2$
* $G_{36}^- = C_3^2 \rtimes C_2^2$
* $G_{36}^+ = C_3^2 \rtimes C_4$
* $G_{72} = C_3^2 \rtimes D_4$
* $A_5$
* $S_5$
Note: Each of these groups also has a dedicated function in this module
that returns the group immediately, using generators that were found by
this search procedure.
The search procedure serves as a record of how these generators were
found. Also, due to randomness in the generation of the elements of
permutation groups, it can be called again, in order to (probably) get
different generators for the same groups.
Parameters
==========
targets : list of :py:class:`~.S6TransitiveSubgroups` values
The groups you want to find.
print_report : bool (default False)
If True, print to stdout the generators found for each group.
Returns
=======
dict
mapping each name in *targets* to the :py:class:`~.PermutationGroup`
that was found
References
==========
.. [2] https://en.wikipedia.org/wiki/Projective_linear_group#Exceptional_isomorphisms
.. [3] https://en.wikipedia.org/wiki/Automorphisms_of_the_symmetric_and_alternating_groups#PGL%282,5%29
"""
def elts_by_order(G):
"""Sort the elements of a group by their order. """
elts = defaultdict(list)
for g in G.elements:
elts[g.order()].append(g)
return elts
def order_profile(G, name=None):
"""Determine how many elements a group has, of each order. """
elts = elts_by_order(G)
profile = {o:len(e) for o, e in elts.items()}
if name:
print(f'{name}: ' + ' '.join(f'{len(profile[r])}@{r}' for r in sorted(profile.keys())))
return profile
S6 = SymmetricGroup(6)
A6 = AlternatingGroup(6)
S6_by_order = elts_by_order(S6)
def search(existing_gens, needed_gen_orders, order, alt=None, profile=None, anti_profile=None):
"""
Find a transitive subgroup of S6.
Parameters
==========
existing_gens : list of Permutation
Optionally empty list of generators that must be in the group.
needed_gen_orders : list of positive int
Nonempty list of the orders of the additional generators that are
to be found.
order: int
The order of the group being sought.
alt: bool, None
If True, require the group to be contained in A6.
If False, require the group not to be contained in A6.
profile : dict
If given, the group's order profile must equal this.
anti_profile : dict
If given, the group's order profile must *not* equal this.
"""
for gens in itertools.product(*[S6_by_order[n] for n in needed_gen_orders]):
if len(set(gens)) < len(gens):
continue
G = PermutationGroup(existing_gens + list(gens))
if G.order() == order and G.is_transitive():
if alt is not None and G.is_subgroup(A6) != alt:
continue
if profile and order_profile(G) != profile:
continue
if anti_profile and order_profile(G) == anti_profile:
continue
return G
def match_known_group(G, alt=None):
needed = [g.order() for g in G.generators]
return search([], needed, G.order(), alt=alt, profile=order_profile(G))
found = {}
def finish_up(name, G):
found[name] = G
if print_report:
print("=" * 40)
print(f"{name}:")
print(G.generators)
if S6TransitiveSubgroups.A4 in targets or S6TransitiveSubgroups.A4xC2 in targets:
A4_in_S6 = match_known_group(AlternatingGroup(4))
finish_up(S6TransitiveSubgroups.A4, A4_in_S6)
if S6TransitiveSubgroups.S4m in targets or S6TransitiveSubgroups.S4xC2 in targets:
S4m_in_S6 = match_known_group(SymmetricGroup(4), alt=False)
finish_up(S6TransitiveSubgroups.S4m, S4m_in_S6)
if S6TransitiveSubgroups.S4p in targets:
S4p_in_S6 = match_known_group(SymmetricGroup(4), alt=True)
finish_up(S6TransitiveSubgroups.S4p, S4p_in_S6)
if S6TransitiveSubgroups.A4xC2 in targets:
A4xC2_in_S6 = search(A4_in_S6.generators, [2], 24, anti_profile=order_profile(SymmetricGroup(4)))
finish_up(S6TransitiveSubgroups.A4xC2, A4xC2_in_S6)
if S6TransitiveSubgroups.S4xC2 in targets:
S4xC2_in_S6 = search(S4m_in_S6.generators, [2], 48)
finish_up(S6TransitiveSubgroups.S4xC2, S4xC2_in_S6)
# For the normal factor N = C3^2 in any of the G_n subgroups, we take one
# obvious instance of C3^2 in S6:
N_gens = [Permutation(5)(0, 1, 2), Permutation(5)(3, 4, 5)]
if S6TransitiveSubgroups.G18 in targets:
G18_in_S6 = search(N_gens, [2], 18)
finish_up(S6TransitiveSubgroups.G18, G18_in_S6)
if S6TransitiveSubgroups.G36m in targets:
G36m_in_S6 = search(N_gens, [2, 2], 36, alt=False)
finish_up(S6TransitiveSubgroups.G36m, G36m_in_S6)
if S6TransitiveSubgroups.G36p in targets:
G36p_in_S6 = search(N_gens, [4], 36, alt=True)
finish_up(S6TransitiveSubgroups.G36p, G36p_in_S6)
if S6TransitiveSubgroups.G72 in targets:
G72_in_S6 = search(N_gens, [4, 2], 72)
finish_up(S6TransitiveSubgroups.G72, G72_in_S6)
# The PSL2(F5) and PGL2(F5) subgroups are isomorphic to A5 and S5, resp.
if S6TransitiveSubgroups.PSL2F5 in targets:
PSL2F5_in_S6 = match_known_group(AlternatingGroup(5))
finish_up(S6TransitiveSubgroups.PSL2F5, PSL2F5_in_S6)
if S6TransitiveSubgroups.PGL2F5 in targets:
PGL2F5_in_S6 = match_known_group(SymmetricGroup(5))
finish_up(S6TransitiveSubgroups.PGL2F5, PGL2F5_in_S6)
# There is little need to "search" for any of the groups C6, S3, D6, A6,
# or S6, since they all have obvious realizations within S6. However, we
# support them here just in case a random representation is desired.
if S6TransitiveSubgroups.C6 in targets:
C6 = match_known_group(CyclicGroup(6))
finish_up(S6TransitiveSubgroups.C6, C6)
if S6TransitiveSubgroups.S3 in targets:
S3 = match_known_group(SymmetricGroup(3))
finish_up(S6TransitiveSubgroups.S3, S3)
if S6TransitiveSubgroups.D6 in targets:
D6 = match_known_group(DihedralGroup(6))
finish_up(S6TransitiveSubgroups.D6, D6)
if S6TransitiveSubgroups.A6 in targets:
A6 = match_known_group(A6)
finish_up(S6TransitiveSubgroups.A6, A6)
if S6TransitiveSubgroups.S6 in targets:
S6 = match_known_group(S6)
finish_up(S6TransitiveSubgroups.S6, S6)
return found
PK ]ZZZ�%�9 9 ! sympy/combinatorics/generators.pyfrom sympy.combinatorics.permutations import Permutation
from sympy.core.symbol import symbols
from sympy.matrices import Matrix
from sympy.utilities.iterables import variations, rotate_left
def symmetric(n):
"""
Generates the symmetric group of order n, Sn.
Examples
========
>>> from sympy.combinatorics.generators import symmetric
>>> list(symmetric(3))
[(2), (1 2), (2)(0 1), (0 1 2), (0 2 1), (0 2)]
"""
for perm in variations(range(n), n):
yield Permutation(perm)
def cyclic(n):
"""
Generates the cyclic group of order n, Cn.
Examples
========
>>> from sympy.combinatorics.generators import cyclic
>>> list(cyclic(5))
[(4), (0 1 2 3 4), (0 2 4 1 3),
(0 3 1 4 2), (0 4 3 2 1)]
See Also
========
dihedral
"""
gen = list(range(n))
for i in range(n):
yield Permutation(gen)
gen = rotate_left(gen, 1)
def alternating(n):
"""
Generates the alternating group of order n, An.
Examples
========
>>> from sympy.combinatorics.generators import alternating
>>> list(alternating(3))
[(2), (0 1 2), (0 2 1)]
"""
for perm in variations(range(n), n):
p = Permutation(perm)
if p.is_even:
yield p
def dihedral(n):
"""
Generates the dihedral group of order 2n, Dn.
The result is given as a subgroup of Sn, except for the special cases n=1
(the group S2) and n=2 (the Klein 4-group) where that's not possible
and embeddings in S2 and S4 respectively are given.
Examples
========
>>> from sympy.combinatorics.generators import dihedral
>>> list(dihedral(3))
[(2), (0 2), (0 1 2), (1 2), (0 2 1), (2)(0 1)]
See Also
========
cyclic
"""
if n == 1:
yield Permutation([0, 1])
yield Permutation([1, 0])
elif n == 2:
yield Permutation([0, 1, 2, 3])
yield Permutation([1, 0, 3, 2])
yield Permutation([2, 3, 0, 1])
yield Permutation([3, 2, 1, 0])
else:
gen = list(range(n))
for i in range(n):
yield Permutation(gen)
yield Permutation(gen[::-1])
gen = rotate_left(gen, 1)
def rubik_cube_generators():
"""Return the permutations of the 3x3 Rubik's cube, see
https://www.gap-system.org/Doc/Examples/rubik.html
"""
a = [
[(1, 3, 8, 6), (2, 5, 7, 4), (9, 33, 25, 17), (10, 34, 26, 18),
(11, 35, 27, 19)],
[(9, 11, 16, 14), (10, 13, 15, 12), (1, 17, 41, 40), (4, 20, 44, 37),
(6, 22, 46, 35)],
[(17, 19, 24, 22), (18, 21, 23, 20), (6, 25, 43, 16), (7, 28, 42, 13),
(8, 30, 41, 11)],
[(25, 27, 32, 30), (26, 29, 31, 28), (3, 38, 43, 19), (5, 36, 45, 21),
(8, 33, 48, 24)],
[(33, 35, 40, 38), (34, 37, 39, 36), (3, 9, 46, 32), (2, 12, 47, 29),
(1, 14, 48, 27)],
[(41, 43, 48, 46), (42, 45, 47, 44), (14, 22, 30, 38),
(15, 23, 31, 39), (16, 24, 32, 40)]
]
return [Permutation([[i - 1 for i in xi] for xi in x], size=48) for x in a]
def rubik(n):
"""Return permutations for an nxn Rubik's cube.
Permutations returned are for rotation of each of the slice
from the face up to the last face for each of the 3 sides (in this order):
front, right and bottom. Hence, the first n - 1 permutations are for the
slices from the front.
"""
if n < 2:
raise ValueError('dimension of cube must be > 1')
# 1-based reference to rows and columns in Matrix
def getr(f, i):
return faces[f].col(n - i)
def getl(f, i):
return faces[f].col(i - 1)
def getu(f, i):
return faces[f].row(i - 1)
def getd(f, i):
return faces[f].row(n - i)
def setr(f, i, s):
faces[f][:, n - i] = Matrix(n, 1, s)
def setl(f, i, s):
faces[f][:, i - 1] = Matrix(n, 1, s)
def setu(f, i, s):
faces[f][i - 1, :] = Matrix(1, n, s)
def setd(f, i, s):
faces[f][n - i, :] = Matrix(1, n, s)
# motion of a single face
def cw(F, r=1):
for _ in range(r):
face = faces[F]
rv = []
for c in range(n):
for r in range(n - 1, -1, -1):
rv.append(face[r, c])
faces[F] = Matrix(n, n, rv)
def ccw(F):
cw(F, 3)
# motion of plane i from the F side;
# fcw(0) moves the F face, fcw(1) moves the plane
# just behind the front face, etc...
def fcw(i, r=1):
for _ in range(r):
if i == 0:
cw(F)
i += 1
temp = getr(L, i)
setr(L, i, list(getu(D, i)))
setu(D, i, list(reversed(getl(R, i))))
setl(R, i, list(getd(U, i)))
setd(U, i, list(reversed(temp)))
i -= 1
def fccw(i):
fcw(i, 3)
# motion of the entire cube from the F side
def FCW(r=1):
for _ in range(r):
cw(F)
ccw(B)
cw(U)
t = faces[U]
cw(L)
faces[U] = faces[L]
cw(D)
faces[L] = faces[D]
cw(R)
faces[D] = faces[R]
faces[R] = t
def FCCW():
FCW(3)
# motion of the entire cube from the U side
def UCW(r=1):
for _ in range(r):
cw(U)
ccw(D)
t = faces[F]
faces[F] = faces[R]
faces[R] = faces[B]
faces[B] = faces[L]
faces[L] = t
def UCCW():
UCW(3)
# defining the permutations for the cube
U, F, R, B, L, D = names = symbols('U, F, R, B, L, D')
# the faces are represented by nxn matrices
faces = {}
count = 0
for fi in range(6):
f = []
for a in range(n**2):
f.append(count)
count += 1
faces[names[fi]] = Matrix(n, n, f)
# this will either return the value of the current permutation
# (show != 1) or else append the permutation to the group, g
def perm(show=0):
# add perm to the list of perms
p = []
for f in names:
p.extend(faces[f])
if show:
return p
g.append(Permutation(p))
g = [] # container for the group's permutations
I = list(range(6*n**2)) # the identity permutation used for checking
# define permutations corresponding to cw rotations of the planes
# up TO the last plane from that direction; by not including the
# last plane, the orientation of the cube is maintained.
# F slices
for i in range(n - 1):
fcw(i)
perm()
fccw(i) # restore
assert perm(1) == I
# R slices
# bring R to front
UCW()
for i in range(n - 1):
fcw(i)
# put it back in place
UCCW()
# record
perm()
# restore
# bring face to front
UCW()
fccw(i)
# restore
UCCW()
assert perm(1) == I
# D slices
# bring up bottom
FCW()
UCCW()
FCCW()
for i in range(n - 1):
# turn strip
fcw(i)
# put bottom back on the bottom
FCW()
UCW()
FCCW()
# record
perm()
# restore
# bring up bottom
FCW()
UCCW()
FCCW()
# turn strip
fccw(i)
# put bottom back on the bottom
FCW()
UCW()
FCCW()
assert perm(1) == I
return g
PK ]ZZZ��h��+ �+ sympy/combinatorics/graycode.pyfrom sympy.core import Basic, Integer
import random
class GrayCode(Basic):
"""
A Gray code is essentially a Hamiltonian walk on
a n-dimensional cube with edge length of one.
The vertices of the cube are represented by vectors
whose values are binary. The Hamilton walk visits
each vertex exactly once. The Gray code for a 3d
cube is ['000','100','110','010','011','111','101',
'001'].
A Gray code solves the problem of sequentially
generating all possible subsets of n objects in such
a way that each subset is obtained from the previous
one by either deleting or adding a single object.
In the above example, 1 indicates that the object is
present, and 0 indicates that its absent.
Gray codes have applications in statistics as well when
we want to compute various statistics related to subsets
in an efficient manner.
Examples
========
>>> from sympy.combinatorics import GrayCode
>>> a = GrayCode(3)
>>> list(a.generate_gray())
['000', '001', '011', '010', '110', '111', '101', '100']
>>> a = GrayCode(4)
>>> list(a.generate_gray())
['0000', '0001', '0011', '0010', '0110', '0111', '0101', '0100', \
'1100', '1101', '1111', '1110', '1010', '1011', '1001', '1000']
References
==========
.. [1] Nijenhuis,A. and Wilf,H.S.(1978).
Combinatorial Algorithms. Academic Press.
.. [2] Knuth, D. (2011). The Art of Computer Programming, Vol 4
Addison Wesley
"""
_skip = False
_current = 0
_rank = None
def __new__(cls, n, *args, **kw_args):
"""
Default constructor.
It takes a single argument ``n`` which gives the dimension of the Gray
code. The starting Gray code string (``start``) or the starting ``rank``
may also be given; the default is to start at rank = 0 ('0...0').
Examples
========
>>> from sympy.combinatorics import GrayCode
>>> a = GrayCode(3)
>>> a
GrayCode(3)
>>> a.n
3
>>> a = GrayCode(3, start='100')
>>> a.current
'100'
>>> a = GrayCode(4, rank=4)
>>> a.current
'0110'
>>> a.rank
4
"""
if n < 1 or int(n) != n:
raise ValueError(
'Gray code dimension must be a positive integer, not %i' % n)
n = Integer(n)
args = (n,) + args
obj = Basic.__new__(cls, *args)
if 'start' in kw_args:
obj._current = kw_args["start"]
if len(obj._current) > n:
raise ValueError('Gray code start has length %i but '
'should not be greater than %i' % (len(obj._current), n))
elif 'rank' in kw_args:
if int(kw_args["rank"]) != kw_args["rank"]:
raise ValueError('Gray code rank must be a positive integer, '
'not %i' % kw_args["rank"])
obj._rank = int(kw_args["rank"]) % obj.selections
obj._current = obj.unrank(n, obj._rank)
return obj
def next(self, delta=1):
"""
Returns the Gray code a distance ``delta`` (default = 1) from the
current value in canonical order.
Examples
========
>>> from sympy.combinatorics import GrayCode
>>> a = GrayCode(3, start='110')
>>> a.next().current
'111'
>>> a.next(-1).current
'010'
"""
return GrayCode(self.n, rank=(self.rank + delta) % self.selections)
@property
def selections(self):
"""
Returns the number of bit vectors in the Gray code.
Examples
========
>>> from sympy.combinatorics import GrayCode
>>> a = GrayCode(3)
>>> a.selections
8
"""
return 2**self.n
@property
def n(self):
"""
Returns the dimension of the Gray code.
Examples
========
>>> from sympy.combinatorics import GrayCode
>>> a = GrayCode(5)
>>> a.n
5
"""
return self.args[0]
def generate_gray(self, **hints):
"""
Generates the sequence of bit vectors of a Gray Code.
Examples
========
>>> from sympy.combinatorics import GrayCode
>>> a = GrayCode(3)
>>> list(a.generate_gray())
['000', '001', '011', '010', '110', '111', '101', '100']
>>> list(a.generate_gray(start='011'))
['011', '010', '110', '111', '101', '100']
>>> list(a.generate_gray(rank=4))
['110', '111', '101', '100']
See Also
========
skip
References
==========
.. [1] Knuth, D. (2011). The Art of Computer Programming,
Vol 4, Addison Wesley
"""
bits = self.n
start = None
if "start" in hints:
start = hints["start"]
elif "rank" in hints:
start = GrayCode.unrank(self.n, hints["rank"])
if start is not None:
self._current = start
current = self.current
graycode_bin = gray_to_bin(current)
if len(graycode_bin) > self.n:
raise ValueError('Gray code start has length %i but should '
'not be greater than %i' % (len(graycode_bin), bits))
self._current = int(current, 2)
graycode_int = int(''.join(graycode_bin), 2)
for i in range(graycode_int, 1 << bits):
if self._skip:
self._skip = False
else:
yield self.current
bbtc = (i ^ (i + 1))
gbtc = (bbtc ^ (bbtc >> 1))
self._current = (self._current ^ gbtc)
self._current = 0
def skip(self):
"""
Skips the bit generation.
Examples
========
>>> from sympy.combinatorics import GrayCode
>>> a = GrayCode(3)
>>> for i in a.generate_gray():
... if i == '010':
... a.skip()
... print(i)
...
000
001
011
010
111
101
100
See Also
========
generate_gray
"""
self._skip = True
@property
def rank(self):
"""
Ranks the Gray code.
A ranking algorithm determines the position (or rank)
of a combinatorial object among all the objects w.r.t.
a given order. For example, the 4 bit binary reflected
Gray code (BRGC) '0101' has a rank of 6 as it appears in
the 6th position in the canonical ordering of the family
of 4 bit Gray codes.
Examples
========
>>> from sympy.combinatorics import GrayCode
>>> a = GrayCode(3)
>>> list(a.generate_gray())
['000', '001', '011', '010', '110', '111', '101', '100']
>>> GrayCode(3, start='100').rank
7
>>> GrayCode(3, rank=7).current
'100'
See Also
========
unrank
References
==========
.. [1] https://web.archive.org/web/20200224064753/http://statweb.stanford.edu/~susan/courses/s208/node12.html
"""
if self._rank is None:
self._rank = int(gray_to_bin(self.current), 2)
return self._rank
@property
def current(self):
"""
Returns the currently referenced Gray code as a bit string.
Examples
========
>>> from sympy.combinatorics import GrayCode
>>> GrayCode(3, start='100').current
'100'
"""
rv = self._current or '0'
if not isinstance(rv, str):
rv = bin(rv)[2:]
return rv.rjust(self.n, '0')
@classmethod
def unrank(self, n, rank):
"""
Unranks an n-bit sized Gray code of rank k. This method exists
so that a derivative GrayCode class can define its own code of
a given rank.
The string here is generated in reverse order to allow for tail-call
optimization.
Examples
========
>>> from sympy.combinatorics import GrayCode
>>> GrayCode(5, rank=3).current
'00010'
>>> GrayCode.unrank(5, 3)
'00010'
See Also
========
rank
"""
def _unrank(k, n):
if n == 1:
return str(k % 2)
m = 2**(n - 1)
if k < m:
return '0' + _unrank(k, n - 1)
return '1' + _unrank(m - (k % m) - 1, n - 1)
return _unrank(rank, n)
def random_bitstring(n):
"""
Generates a random bitlist of length n.
Examples
========
>>> from sympy.combinatorics.graycode import random_bitstring
>>> random_bitstring(3) # doctest: +SKIP
100
"""
return ''.join([random.choice('01') for i in range(n)])
def gray_to_bin(bin_list):
"""
Convert from Gray coding to binary coding.
We assume big endian encoding.
Examples
========
>>> from sympy.combinatorics.graycode import gray_to_bin
>>> gray_to_bin('100')
'111'
See Also
========
bin_to_gray
"""
b = [bin_list[0]]
for i in range(1, len(bin_list)):
b += str(int(b[i - 1] != bin_list[i]))
return ''.join(b)
def bin_to_gray(bin_list):
"""
Convert from binary coding to gray coding.
We assume big endian encoding.
Examples
========
>>> from sympy.combinatorics.graycode import bin_to_gray
>>> bin_to_gray('111')
'100'
See Also
========
gray_to_bin
"""
b = [bin_list[0]]
for i in range(1, len(bin_list)):
b += str(int(bin_list[i]) ^ int(bin_list[i - 1]))
return ''.join(b)
def get_subset_from_bitstring(super_set, bitstring):
"""
Gets the subset defined by the bitstring.
Examples
========
>>> from sympy.combinatorics.graycode import get_subset_from_bitstring
>>> get_subset_from_bitstring(['a', 'b', 'c', 'd'], '0011')
['c', 'd']
>>> get_subset_from_bitstring(['c', 'a', 'c', 'c'], '1100')
['c', 'a']
See Also
========
graycode_subsets
"""
if len(super_set) != len(bitstring):
raise ValueError("The sizes of the lists are not equal")
return [super_set[i] for i, j in enumerate(bitstring)
if bitstring[i] == '1']
def graycode_subsets(gray_code_set):
"""
Generates the subsets as enumerated by a Gray code.
Examples
========
>>> from sympy.combinatorics.graycode import graycode_subsets
>>> list(graycode_subsets(['a', 'b', 'c']))
[[], ['c'], ['b', 'c'], ['b'], ['a', 'b'], ['a', 'b', 'c'], \
['a', 'c'], ['a']]
>>> list(graycode_subsets(['a', 'b', 'c', 'c']))
[[], ['c'], ['c', 'c'], ['c'], ['b', 'c'], ['b', 'c', 'c'], \
['b', 'c'], ['b'], ['a', 'b'], ['a', 'b', 'c'], ['a', 'b', 'c', 'c'], \
['a', 'b', 'c'], ['a', 'c'], ['a', 'c', 'c'], ['a', 'c'], ['a']]
See Also
========
get_subset_from_bitstring
"""
for bitstring in list(GrayCode(len(gray_code_set)).generate_gray()):
yield get_subset_from_bitstring(gray_code_set, bitstring)
PK ]ZZZ��o� � ' sympy/combinatorics/group_constructs.pyfrom sympy.combinatorics.perm_groups import PermutationGroup
from sympy.combinatorics.permutations import Permutation
from sympy.utilities.iterables import uniq
_af_new = Permutation._af_new
def DirectProduct(*groups):
"""
Returns the direct product of several groups as a permutation group.
Explanation
===========
This is implemented much like the __mul__ procedure for taking the direct
product of two permutation groups, but the idea of shifting the
generators is realized in the case of an arbitrary number of groups.
A call to DirectProduct(G1, G2, ..., Gn) is generally expected to be faster
than a call to G1*G2*...*Gn (and thus the need for this algorithm).
Examples
========
>>> from sympy.combinatorics.group_constructs import DirectProduct
>>> from sympy.combinatorics.named_groups import CyclicGroup
>>> C = CyclicGroup(4)
>>> G = DirectProduct(C, C, C)
>>> G.order()
64
See Also
========
sympy.combinatorics.perm_groups.PermutationGroup.__mul__
"""
degrees = []
gens_count = []
total_degree = 0
total_gens = 0
for group in groups:
current_deg = group.degree
current_num_gens = len(group.generators)
degrees.append(current_deg)
total_degree += current_deg
gens_count.append(current_num_gens)
total_gens += current_num_gens
array_gens = []
for i in range(total_gens):
array_gens.append(list(range(total_degree)))
current_gen = 0
current_deg = 0
for i in range(len(gens_count)):
for j in range(current_gen, current_gen + gens_count[i]):
gen = ((groups[i].generators)[j - current_gen]).array_form
array_gens[j][current_deg:current_deg + degrees[i]] = \
[x + current_deg for x in gen]
current_gen += gens_count[i]
current_deg += degrees[i]
perm_gens = list(uniq([_af_new(list(a)) for a in array_gens]))
return PermutationGroup(perm_gens, dups=False)
PK ]ZZZ����# �# $ sympy/combinatorics/group_numbers.pyfrom itertools import chain, combinations
from sympy.external.gmpy import gcd
from sympy.ntheory.factor_ import factorint
from sympy.utilities.misc import as_int
def _is_nilpotent_number(factors: dict) -> bool:
""" Check whether `n` is a nilpotent number.
Note that ``factors`` is a prime factorization of `n`.
This is a low-level helper for ``is_nilpotent_number``, for internal use.
"""
for p in factors.keys():
for q, e in factors.items():
# We want to calculate
# any(pow(q, k, p) == 1 for k in range(1, e + 1))
m = 1
for _ in range(e):
m = m*q % p
if m == 1:
return False
return True
def is_nilpotent_number(n) -> bool:
"""
Check whether `n` is a nilpotent number. A number `n` is said to be
nilpotent if and only if every finite group of order `n` is nilpotent.
For more information see [1]_.
Examples
========
>>> from sympy.combinatorics.group_numbers import is_nilpotent_number
>>> from sympy import randprime
>>> is_nilpotent_number(21)
False
>>> is_nilpotent_number(randprime(1, 30)**12)
True
References
==========
.. [1] Pakianathan, J., Shankar, K., Nilpotent Numbers,
The American Mathematical Monthly, 107(7), 631-634.
.. [2] https://oeis.org/A056867
"""
n = as_int(n)
if n <= 0:
raise ValueError("n must be a positive integer, not %i" % n)
return _is_nilpotent_number(factorint(n))
def is_abelian_number(n) -> bool:
"""
Check whether `n` is an abelian number. A number `n` is said to be abelian
if and only if every finite group of order `n` is abelian. For more
information see [1]_.
Examples
========
>>> from sympy.combinatorics.group_numbers import is_abelian_number
>>> from sympy import randprime
>>> is_abelian_number(4)
True
>>> is_abelian_number(randprime(1, 2000)**2)
True
>>> is_abelian_number(60)
False
References
==========
.. [1] Pakianathan, J., Shankar, K., Nilpotent Numbers,
The American Mathematical Monthly, 107(7), 631-634.
.. [2] https://oeis.org/A051532
"""
n = as_int(n)
if n <= 0:
raise ValueError("n must be a positive integer, not %i" % n)
factors = factorint(n)
return all(e < 3 for e in factors.values()) and _is_nilpotent_number(factors)
def is_cyclic_number(n) -> bool:
"""
Check whether `n` is a cyclic number. A number `n` is said to be cyclic
if and only if every finite group of order `n` is cyclic. For more
information see [1]_.
Examples
========
>>> from sympy.combinatorics.group_numbers import is_cyclic_number
>>> from sympy import randprime
>>> is_cyclic_number(15)
True
>>> is_cyclic_number(randprime(1, 2000)**2)
False
>>> is_cyclic_number(4)
False
References
==========
.. [1] Pakianathan, J., Shankar, K., Nilpotent Numbers,
The American Mathematical Monthly, 107(7), 631-634.
.. [2] https://oeis.org/A003277
"""
n = as_int(n)
if n <= 0:
raise ValueError("n must be a positive integer, not %i" % n)
factors = factorint(n)
return all(e == 1 for e in factors.values()) and _is_nilpotent_number(factors)
def _holder_formula(prime_factors):
r""" Number of groups of order `n`.
where `n` is squarefree and its prime factors are ``prime_factors``.
i.e., ``n == math.prod(prime_factors)``
Explanation
===========
When `n` is squarefree, the number of groups of order `n` is expressed by
.. math ::
\sum_{d \mid n} \prod_p \frac{p^{c(p, d)} - 1}{p - 1}
where `n=de`, `p` is the prime factor of `e`,
and `c(p, d)` is the number of prime factors `q` of `d` such that `q \equiv 1 \pmod{p}` [2]_.
The formula is elegant, but can be improved when implemented as an algorithm.
Since `n` is assumed to be squarefree, the divisor `d` of `n` can be identified with the power set of prime factors.
We let `N` be the set of prime factors of `n`.
`F = \{p \in N : \forall q \in N, q \not\equiv 1 \pmod{p} \}, M = N \setminus F`, we have the following.
.. math ::
\sum_{d \in 2^{M}} \prod_{p \in M \setminus d} \frac{p^{c(p, F \cup d)} - 1}{p - 1}
Practically, many prime factors are expected to be members of `F`, thus reducing computation time.
Parameters
==========
prime_factors : set
The set of prime factors of ``n``. where `n` is squarefree.
Returns
=======
int : Number of groups of order ``n``
Examples
========
>>> from sympy.combinatorics.group_numbers import _holder_formula
>>> _holder_formula({2}) # n = 2
1
>>> _holder_formula({2, 3}) # n = 2*3 = 6
2
See Also
========
groups_count
References
==========
.. [1] Otto Holder, Die Gruppen der Ordnungen p^3, pq^2, pqr, p^4,
Math. Ann. 43 pp. 301-412 (1893).
http://dx.doi.org/10.1007/BF01443651
.. [2] John H. Conway, Heiko Dietrich and E.A. O'Brien,
Counting groups: gnus, moas and other exotica
The Mathematical Intelligencer 30, 6-15 (2008)
https://doi.org/10.1007/BF02985731
"""
F = {p for p in prime_factors if all(q % p != 1 for q in prime_factors)}
M = prime_factors - F
s = 0
powerset = chain.from_iterable(combinations(M, r) for r in range(len(M)+1))
for ps in powerset:
ps = set(ps)
prod = 1
for p in M - ps:
c = len([q for q in F | ps if q % p == 1])
prod *= (p**c - 1) // (p - 1)
if not prod:
break
s += prod
return s
def groups_count(n):
r""" Number of groups of order `n`.
In [1]_, ``gnu(n)`` is given, so we follow this notation here as well.
Parameters
==========
n : Integer
``n`` is a positive integer
Returns
=======
int : ``gnu(n)``
Raises
======
ValueError
Number of groups of order ``n`` is unknown or not implemented.
For example, gnu(`2^{11}`) is not yet known.
On the other hand, gnu(12) is known to be 5,
but this has not yet been implemented in this function.
Examples
========
>>> from sympy.combinatorics.group_numbers import groups_count
>>> groups_count(3) # There is only one cyclic group of order 3
1
>>> # There are two groups of order 10: the cyclic group and the dihedral group
>>> groups_count(10)
2
See Also
========
is_cyclic_number
`n` is cyclic iff gnu(n) = 1
References
==========
.. [1] John H. Conway, Heiko Dietrich and E.A. O'Brien,
Counting groups: gnus, moas and other exotica
The Mathematical Intelligencer 30, 6-15 (2008)
https://doi.org/10.1007/BF02985731
.. [2] https://oeis.org/A000001
"""
n = as_int(n)
if n <= 0:
raise ValueError("n must be a positive integer, not %i" % n)
factors = factorint(n)
if len(factors) == 1:
(p, e) = list(factors.items())[0]
if p == 2:
A000679 = [1, 1, 2, 5, 14, 51, 267, 2328, 56092, 10494213, 49487367289]
if e < len(A000679):
return A000679[e]
if p == 3:
A090091 = [1, 1, 2, 5, 15, 67, 504, 9310, 1396077, 5937876645]
if e < len(A090091):
return A090091[e]
if e <= 2: # gnu(p) = 1, gnu(p**2) = 2
return e
if e == 3: # gnu(p**3) = 5
return 5
if e == 4: # if p is an odd prime, gnu(p**4) = 15
return 15
if e == 5: # if p >= 5, gnu(p**5) is expressed by the following equation
return 61 + 2*p + 2*gcd(p-1, 3) + gcd(p-1, 4)
if e == 6: # if p >= 6, gnu(p**6) is expressed by the following equation
return 3*p**2 + 39*p + 344 +\
24*gcd(p-1, 3) + 11*gcd(p-1, 4) + 2*gcd(p-1, 5)
if e == 7: # if p >= 7, gnu(p**7) is expressed by the following equation
if p == 5:
return 34297
return 3*p**5 + 12*p**4 + 44*p**3 + 170*p**2 + 707*p + 2455 +\
(4*p**2 + 44*p + 291)*gcd(p-1, 3) + (p**2 + 19*p + 135)*gcd(p-1, 4) + \
(3*p + 31)*gcd(p-1, 5) + 4*gcd(p-1, 7) + 5*gcd(p-1, 8) + gcd(p-1, 9)
if any(e > 1 for e in factors.values()): # n is not squarefree
# some known values for small n that have more than 1 factor and are not square free (https://oeis.org/A000001)
small = {12: 5, 18: 5, 20: 5, 24: 15, 28: 4, 36: 14, 40: 14, 44: 4, 45: 2, 48: 52,
50: 5, 52: 5, 54: 15, 56: 13, 60: 13, 63: 4, 68: 5, 72: 50, 75: 3, 76: 4,
80: 52, 84: 15, 88: 12, 90: 10, 92: 4}
if n in small:
return small[n]
raise ValueError("Number of groups of order n is unknown or not implemented")
if len(factors) == 2: # n is squarefree semiprime
p, q = list(factors.keys())
if p > q:
p, q = q, p
return 2 if q % p == 1 else 1
return _holder_formula(set(factors.keys()))
PK ]ZZZ�8��I �I $ sympy/combinatorics/homomorphisms.pyimport itertools
from sympy.combinatorics.fp_groups import FpGroup, FpSubgroup, simplify_presentation
from sympy.combinatorics.free_groups import FreeGroup
from sympy.combinatorics.perm_groups import PermutationGroup
from sympy.core.intfunc import igcd
from sympy.functions.combinatorial.numbers import totient
from sympy.core.singleton import S
class GroupHomomorphism:
'''
A class representing group homomorphisms. Instantiate using `homomorphism()`.
References
==========
.. [1] Holt, D., Eick, B. and O'Brien, E. (2005). Handbook of computational group theory.
'''
def __init__(self, domain, codomain, images):
self.domain = domain
self.codomain = codomain
self.images = images
self._inverses = None
self._kernel = None
self._image = None
def _invs(self):
'''
Return a dictionary with `{gen: inverse}` where `gen` is a rewriting
generator of `codomain` (e.g. strong generator for permutation groups)
and `inverse` is an element of its preimage
'''
image = self.image()
inverses = {}
for k in list(self.images.keys()):
v = self.images[k]
if not (v in inverses
or v.is_identity):
inverses[v] = k
if isinstance(self.codomain, PermutationGroup):
gens = image.strong_gens
else:
gens = image.generators
for g in gens:
if g in inverses or g.is_identity:
continue
w = self.domain.identity
if isinstance(self.codomain, PermutationGroup):
parts = image._strong_gens_slp[g][::-1]
else:
parts = g
for s in parts:
if s in inverses:
w = w*inverses[s]
else:
w = w*inverses[s**-1]**-1
inverses[g] = w
return inverses
def invert(self, g):
'''
Return an element of the preimage of ``g`` or of each element
of ``g`` if ``g`` is a list.
Explanation
===========
If the codomain is an FpGroup, the inverse for equal
elements might not always be the same unless the FpGroup's
rewriting system is confluent. However, making a system
confluent can be time-consuming. If it's important, try
`self.codomain.make_confluent()` first.
'''
from sympy.combinatorics import Permutation
from sympy.combinatorics.free_groups import FreeGroupElement
if isinstance(g, (Permutation, FreeGroupElement)):
if isinstance(self.codomain, FpGroup):
g = self.codomain.reduce(g)
if self._inverses is None:
self._inverses = self._invs()
image = self.image()
w = self.domain.identity
if isinstance(self.codomain, PermutationGroup):
gens = image.generator_product(g)[::-1]
else:
gens = g
# the following can't be "for s in gens:"
# because that would be equivalent to
# "for s in gens.array_form:" when g is
# a FreeGroupElement. On the other hand,
# when you call gens by index, the generator
# (or inverse) at position i is returned.
for i in range(len(gens)):
s = gens[i]
if s.is_identity:
continue
if s in self._inverses:
w = w*self._inverses[s]
else:
w = w*self._inverses[s**-1]**-1
return w
elif isinstance(g, list):
return [self.invert(e) for e in g]
def kernel(self):
'''
Compute the kernel of `self`.
'''
if self._kernel is None:
self._kernel = self._compute_kernel()
return self._kernel
def _compute_kernel(self):
G = self.domain
G_order = G.order()
if G_order is S.Infinity:
raise NotImplementedError(
"Kernel computation is not implemented for infinite groups")
gens = []
if isinstance(G, PermutationGroup):
K = PermutationGroup(G.identity)
else:
K = FpSubgroup(G, gens, normal=True)
i = self.image().order()
while K.order()*i != G_order:
r = G.random()
k = r*self.invert(self(r))**-1
if k not in K:
gens.append(k)
if isinstance(G, PermutationGroup):
K = PermutationGroup(gens)
else:
K = FpSubgroup(G, gens, normal=True)
return K
def image(self):
'''
Compute the image of `self`.
'''
if self._image is None:
values = list(set(self.images.values()))
if isinstance(self.codomain, PermutationGroup):
self._image = self.codomain.subgroup(values)
else:
self._image = FpSubgroup(self.codomain, values)
return self._image
def _apply(self, elem):
'''
Apply `self` to `elem`.
'''
if elem not in self.domain:
if isinstance(elem, (list, tuple)):
return [self._apply(e) for e in elem]
raise ValueError("The supplied element does not belong to the domain")
if elem.is_identity:
return self.codomain.identity
else:
images = self.images
value = self.codomain.identity
if isinstance(self.domain, PermutationGroup):
gens = self.domain.generator_product(elem, original=True)
for g in gens:
if g in self.images:
value = images[g]*value
else:
value = images[g**-1]**-1*value
else:
i = 0
for _, p in elem.array_form:
if p < 0:
g = elem[i]**-1
else:
g = elem[i]
value = value*images[g]**p
i += abs(p)
return value
def __call__(self, elem):
return self._apply(elem)
def is_injective(self):
'''
Check if the homomorphism is injective
'''
return self.kernel().order() == 1
def is_surjective(self):
'''
Check if the homomorphism is surjective
'''
im = self.image().order()
oth = self.codomain.order()
if im is S.Infinity and oth is S.Infinity:
return None
else:
return im == oth
def is_isomorphism(self):
'''
Check if `self` is an isomorphism.
'''
return self.is_injective() and self.is_surjective()
def is_trivial(self):
'''
Check is `self` is a trivial homomorphism, i.e. all elements
are mapped to the identity.
'''
return self.image().order() == 1
def compose(self, other):
'''
Return the composition of `self` and `other`, i.e.
the homomorphism phi such that for all g in the domain
of `other`, phi(g) = self(other(g))
'''
if not other.image().is_subgroup(self.domain):
raise ValueError("The image of `other` must be a subgroup of "
"the domain of `self`")
images = {g: self(other(g)) for g in other.images}
return GroupHomomorphism(other.domain, self.codomain, images)
def restrict_to(self, H):
'''
Return the restriction of the homomorphism to the subgroup `H`
of the domain.
'''
if not isinstance(H, PermutationGroup) or not H.is_subgroup(self.domain):
raise ValueError("Given H is not a subgroup of the domain")
domain = H
images = {g: self(g) for g in H.generators}
return GroupHomomorphism(domain, self.codomain, images)
def invert_subgroup(self, H):
'''
Return the subgroup of the domain that is the inverse image
of the subgroup ``H`` of the homomorphism image
'''
if not H.is_subgroup(self.image()):
raise ValueError("Given H is not a subgroup of the image")
gens = []
P = PermutationGroup(self.image().identity)
for h in H.generators:
h_i = self.invert(h)
if h_i not in P:
gens.append(h_i)
P = PermutationGroup(gens)
for k in self.kernel().generators:
if k*h_i not in P:
gens.append(k*h_i)
P = PermutationGroup(gens)
return P
def homomorphism(domain, codomain, gens, images=(), check=True):
'''
Create (if possible) a group homomorphism from the group ``domain``
to the group ``codomain`` defined by the images of the domain's
generators ``gens``. ``gens`` and ``images`` can be either lists or tuples
of equal sizes. If ``gens`` is a proper subset of the group's generators,
the unspecified generators will be mapped to the identity. If the
images are not specified, a trivial homomorphism will be created.
If the given images of the generators do not define a homomorphism,
an exception is raised.
If ``check`` is ``False``, do not check whether the given images actually
define a homomorphism.
'''
if not isinstance(domain, (PermutationGroup, FpGroup, FreeGroup)):
raise TypeError("The domain must be a group")
if not isinstance(codomain, (PermutationGroup, FpGroup, FreeGroup)):
raise TypeError("The codomain must be a group")
generators = domain.generators
if not all(g in generators for g in gens):
raise ValueError("The supplied generators must be a subset of the domain's generators")
if not all(g in codomain for g in images):
raise ValueError("The images must be elements of the codomain")
if images and len(images) != len(gens):
raise ValueError("The number of images must be equal to the number of generators")
gens = list(gens)
images = list(images)
images.extend([codomain.identity]*(len(generators)-len(images)))
gens.extend([g for g in generators if g not in gens])
images = dict(zip(gens,images))
if check and not _check_homomorphism(domain, codomain, images):
raise ValueError("The given images do not define a homomorphism")
return GroupHomomorphism(domain, codomain, images)
def _check_homomorphism(domain, codomain, images):
"""
Check that a given mapping of generators to images defines a homomorphism.
Parameters
==========
domain : PermutationGroup, FpGroup, FreeGroup
codomain : PermutationGroup, FpGroup, FreeGroup
images : dict
The set of keys must be equal to domain.generators.
The values must be elements of the codomain.
"""
pres = domain if hasattr(domain, 'relators') else domain.presentation()
rels = pres.relators
gens = pres.generators
symbols = [g.ext_rep[0] for g in gens]
symbols_to_domain_generators = dict(zip(symbols, domain.generators))
identity = codomain.identity
def _image(r):
w = identity
for symbol, power in r.array_form:
g = symbols_to_domain_generators[symbol]
w *= images[g]**power
return w
for r in rels:
if isinstance(codomain, FpGroup):
s = codomain.equals(_image(r), identity)
if s is None:
# only try to make the rewriting system
# confluent when it can't determine the
# truth of equality otherwise
success = codomain.make_confluent()
s = codomain.equals(_image(r), identity)
if s is None and not success:
raise RuntimeError("Can't determine if the images "
"define a homomorphism. Try increasing "
"the maximum number of rewriting rules "
"(group._rewriting_system.set_max(new_value); "
"the current value is stored in group._rewriting"
"_system.maxeqns)")
else:
s = _image(r).is_identity
if not s:
return False
return True
def orbit_homomorphism(group, omega):
'''
Return the homomorphism induced by the action of the permutation
group ``group`` on the set ``omega`` that is closed under the action.
'''
from sympy.combinatorics import Permutation
from sympy.combinatorics.named_groups import SymmetricGroup
codomain = SymmetricGroup(len(omega))
identity = codomain.identity
omega = list(omega)
images = {g: identity*Permutation([omega.index(o^g) for o in omega]) for g in group.generators}
group._schreier_sims(base=omega)
H = GroupHomomorphism(group, codomain, images)
if len(group.basic_stabilizers) > len(omega):
H._kernel = group.basic_stabilizers[len(omega)]
else:
H._kernel = PermutationGroup([group.identity])
return H
def block_homomorphism(group, blocks):
'''
Return the homomorphism induced by the action of the permutation
group ``group`` on the block system ``blocks``. The latter should be
of the same form as returned by the ``minimal_block`` method for
permutation groups, namely a list of length ``group.degree`` where
the i-th entry is a representative of the block i belongs to.
'''
from sympy.combinatorics import Permutation
from sympy.combinatorics.named_groups import SymmetricGroup
n = len(blocks)
# number the blocks; m is the total number,
# b is such that b[i] is the number of the block i belongs to,
# p is the list of length m such that p[i] is the representative
# of the i-th block
m = 0
p = []
b = [None]*n
for i in range(n):
if blocks[i] == i:
p.append(i)
b[i] = m
m += 1
for i in range(n):
b[i] = b[blocks[i]]
codomain = SymmetricGroup(m)
# the list corresponding to the identity permutation in codomain
identity = range(m)
images = {g: Permutation([b[p[i]^g] for i in identity]) for g in group.generators}
H = GroupHomomorphism(group, codomain, images)
return H
def group_isomorphism(G, H, isomorphism=True):
'''
Compute an isomorphism between 2 given groups.
Parameters
==========
G : A finite ``FpGroup`` or a ``PermutationGroup``.
First group.
H : A finite ``FpGroup`` or a ``PermutationGroup``
Second group.
isomorphism : bool
This is used to avoid the computation of homomorphism
when the user only wants to check if there exists
an isomorphism between the groups.
Returns
=======
If isomorphism = False -- Returns a boolean.
If isomorphism = True -- Returns a boolean and an isomorphism between `G` and `H`.
Examples
========
>>> from sympy.combinatorics import free_group, Permutation
>>> from sympy.combinatorics.perm_groups import PermutationGroup
>>> from sympy.combinatorics.fp_groups import FpGroup
>>> from sympy.combinatorics.homomorphisms import group_isomorphism
>>> from sympy.combinatorics.named_groups import DihedralGroup, AlternatingGroup
>>> D = DihedralGroup(8)
>>> p = Permutation(0, 1, 2, 3, 4, 5, 6, 7)
>>> P = PermutationGroup(p)
>>> group_isomorphism(D, P)
(False, None)
>>> F, a, b = free_group("a, b")
>>> G = FpGroup(F, [a**3, b**3, (a*b)**2])
>>> H = AlternatingGroup(4)
>>> (check, T) = group_isomorphism(G, H)
>>> check
True
>>> T(b*a*b**-1*a**-1*b**-1)
(0 2 3)
Notes
=====
Uses the approach suggested by Robert Tarjan to compute the isomorphism between two groups.
First, the generators of ``G`` are mapped to the elements of ``H`` and
we check if the mapping induces an isomorphism.
'''
if not isinstance(G, (PermutationGroup, FpGroup)):
raise TypeError("The group must be a PermutationGroup or an FpGroup")
if not isinstance(H, (PermutationGroup, FpGroup)):
raise TypeError("The group must be a PermutationGroup or an FpGroup")
if isinstance(G, FpGroup) and isinstance(H, FpGroup):
G = simplify_presentation(G)
H = simplify_presentation(H)
# Two infinite FpGroups with the same generators are isomorphic
# when the relators are same but are ordered differently.
if G.generators == H.generators and (G.relators).sort() == (H.relators).sort():
if not isomorphism:
return True
return (True, homomorphism(G, H, G.generators, H.generators))
# `_H` is the permutation group isomorphic to `H`.
_H = H
g_order = G.order()
h_order = H.order()
if g_order is S.Infinity:
raise NotImplementedError("Isomorphism methods are not implemented for infinite groups.")
if isinstance(H, FpGroup):
if h_order is S.Infinity:
raise NotImplementedError("Isomorphism methods are not implemented for infinite groups.")
_H, h_isomorphism = H._to_perm_group()
if (g_order != h_order) or (G.is_abelian != H.is_abelian):
if not isomorphism:
return False
return (False, None)
if not isomorphism:
# Two groups of the same cyclic numbered order
# are isomorphic to each other.
n = g_order
if (igcd(n, totient(n))) == 1:
return True
# Match the generators of `G` with subsets of `_H`
gens = list(G.generators)
for subset in itertools.permutations(_H, len(gens)):
images = list(subset)
images.extend([_H.identity]*(len(G.generators)-len(images)))
_images = dict(zip(gens,images))
if _check_homomorphism(G, _H, _images):
if isinstance(H, FpGroup):
images = h_isomorphism.invert(images)
T = homomorphism(G, H, G.generators, images, check=False)
if T.is_isomorphism():
# It is a valid isomorphism
if not isomorphism:
return True
return (True, T)
if not isomorphism:
return False
return (False, None)
def is_isomorphic(G, H):
'''
Check if the groups are isomorphic to each other
Parameters
==========
G : A finite ``FpGroup`` or a ``PermutationGroup``
First group.
H : A finite ``FpGroup`` or a ``PermutationGroup``
Second group.
Returns
=======
boolean
'''
return group_isomorphism(G, H, isomorphism=False)
PK ]ZZZl��O� � # sympy/combinatorics/named_groups.pyfrom sympy.combinatorics.group_constructs import DirectProduct
from sympy.combinatorics.perm_groups import PermutationGroup
from sympy.combinatorics.permutations import Permutation
_af_new = Permutation._af_new
def AbelianGroup(*cyclic_orders):
"""
Returns the direct product of cyclic groups with the given orders.
Explanation
===========
According to the structure theorem for finite abelian groups ([1]),
every finite abelian group can be written as the direct product of
finitely many cyclic groups.
Examples
========
>>> from sympy.combinatorics.named_groups import AbelianGroup
>>> AbelianGroup(3, 4)
PermutationGroup([
(6)(0 1 2),
(3 4 5 6)])
>>> _.is_group
True
See Also
========
DirectProduct
References
==========
.. [1] https://groupprops.subwiki.org/wiki/Structure_theorem_for_finitely_generated_abelian_groups
"""
groups = []
degree = 0
order = 1
for size in cyclic_orders:
degree += size
order *= size
groups.append(CyclicGroup(size))
G = DirectProduct(*groups)
G._is_abelian = True
G._degree = degree
G._order = order
return G
def AlternatingGroup(n):
"""
Generates the alternating group on ``n`` elements as a permutation group.
Explanation
===========
For ``n > 2``, the generators taken are ``(0 1 2), (0 1 2 ... n-1)`` for
``n`` odd
and ``(0 1 2), (1 2 ... n-1)`` for ``n`` even (See [1], p.31, ex.6.9.).
After the group is generated, some of its basic properties are set.
The cases ``n = 1, 2`` are handled separately.
Examples
========
>>> from sympy.combinatorics.named_groups import AlternatingGroup
>>> G = AlternatingGroup(4)
>>> G.is_group
True
>>> a = list(G.generate_dimino())
>>> len(a)
12
>>> all(perm.is_even for perm in a)
True
See Also
========
SymmetricGroup, CyclicGroup, DihedralGroup
References
==========
.. [1] Armstrong, M. "Groups and Symmetry"
"""
# small cases are special
if n in (1, 2):
return PermutationGroup([Permutation([0])])
a = list(range(n))
a[0], a[1], a[2] = a[1], a[2], a[0]
gen1 = a
if n % 2:
a = list(range(1, n))
a.append(0)
gen2 = a
else:
a = list(range(2, n))
a.append(1)
a.insert(0, 0)
gen2 = a
gens = [gen1, gen2]
if gen1 == gen2:
gens = gens[:1]
G = PermutationGroup([_af_new(a) for a in gens], dups=False)
set_alternating_group_properties(G, n, n)
G._is_alt = True
return G
def set_alternating_group_properties(G, n, degree):
"""Set known properties of an alternating group. """
if n < 4:
G._is_abelian = True
G._is_nilpotent = True
else:
G._is_abelian = False
G._is_nilpotent = False
if n < 5:
G._is_solvable = True
else:
G._is_solvable = False
G._degree = degree
G._is_transitive = True
G._is_dihedral = False
def CyclicGroup(n):
"""
Generates the cyclic group of order ``n`` as a permutation group.
Explanation
===========
The generator taken is the ``n``-cycle ``(0 1 2 ... n-1)``
(in cycle notation). After the group is generated, some of its basic
properties are set.
Examples
========
>>> from sympy.combinatorics.named_groups import CyclicGroup
>>> G = CyclicGroup(6)
>>> G.is_group
True
>>> G.order()
6
>>> list(G.generate_schreier_sims(af=True))
[[0, 1, 2, 3, 4, 5], [1, 2, 3, 4, 5, 0], [2, 3, 4, 5, 0, 1],
[3, 4, 5, 0, 1, 2], [4, 5, 0, 1, 2, 3], [5, 0, 1, 2, 3, 4]]
See Also
========
SymmetricGroup, DihedralGroup, AlternatingGroup
"""
a = list(range(1, n))
a.append(0)
gen = _af_new(a)
G = PermutationGroup([gen])
G._is_abelian = True
G._is_nilpotent = True
G._is_solvable = True
G._degree = n
G._is_transitive = True
G._order = n
G._is_dihedral = (n == 2)
return G
def DihedralGroup(n):
r"""
Generates the dihedral group `D_n` as a permutation group.
Explanation
===========
The dihedral group `D_n` is the group of symmetries of the regular
``n``-gon. The generators taken are the ``n``-cycle ``a = (0 1 2 ... n-1)``
(a rotation of the ``n``-gon) and ``b = (0 n-1)(1 n-2)...``
(a reflection of the ``n``-gon) in cycle rotation. It is easy to see that
these satisfy ``a**n = b**2 = 1`` and ``bab = ~a`` so they indeed generate
`D_n` (See [1]). After the group is generated, some of its basic properties
are set.
Examples
========
>>> from sympy.combinatorics.named_groups import DihedralGroup
>>> G = DihedralGroup(5)
>>> G.is_group
True
>>> a = list(G.generate_dimino())
>>> [perm.cyclic_form for perm in a]
[[], [[0, 1, 2, 3, 4]], [[0, 2, 4, 1, 3]],
[[0, 3, 1, 4, 2]], [[0, 4, 3, 2, 1]], [[0, 4], [1, 3]],
[[1, 4], [2, 3]], [[0, 1], [2, 4]], [[0, 2], [3, 4]],
[[0, 3], [1, 2]]]
See Also
========
SymmetricGroup, CyclicGroup, AlternatingGroup
References
==========
.. [1] https://en.wikipedia.org/wiki/Dihedral_group
"""
# small cases are special
if n == 1:
return PermutationGroup([Permutation([1, 0])])
if n == 2:
return PermutationGroup([Permutation([1, 0, 3, 2]),
Permutation([2, 3, 0, 1]), Permutation([3, 2, 1, 0])])
a = list(range(1, n))
a.append(0)
gen1 = _af_new(a)
a = list(range(n))
a.reverse()
gen2 = _af_new(a)
G = PermutationGroup([gen1, gen2])
# if n is a power of 2, group is nilpotent
if n & (n-1) == 0:
G._is_nilpotent = True
else:
G._is_nilpotent = False
G._is_dihedral = True
G._is_abelian = False
G._is_solvable = True
G._degree = n
G._is_transitive = True
G._order = 2*n
return G
def SymmetricGroup(n):
"""
Generates the symmetric group on ``n`` elements as a permutation group.
Explanation
===========
The generators taken are the ``n``-cycle
``(0 1 2 ... n-1)`` and the transposition ``(0 1)`` (in cycle notation).
(See [1]). After the group is generated, some of its basic properties
are set.
Examples
========
>>> from sympy.combinatorics.named_groups import SymmetricGroup
>>> G = SymmetricGroup(4)
>>> G.is_group
True
>>> G.order()
24
>>> list(G.generate_schreier_sims(af=True))
[[0, 1, 2, 3], [1, 2, 3, 0], [2, 3, 0, 1], [3, 1, 2, 0], [0, 2, 3, 1],
[1, 3, 0, 2], [2, 0, 1, 3], [3, 2, 0, 1], [0, 3, 1, 2], [1, 0, 2, 3],
[2, 1, 3, 0], [3, 0, 1, 2], [0, 1, 3, 2], [1, 2, 0, 3], [2, 3, 1, 0],
[3, 1, 0, 2], [0, 2, 1, 3], [1, 3, 2, 0], [2, 0, 3, 1], [3, 2, 1, 0],
[0, 3, 2, 1], [1, 0, 3, 2], [2, 1, 0, 3], [3, 0, 2, 1]]
See Also
========
CyclicGroup, DihedralGroup, AlternatingGroup
References
==========
.. [1] https://en.wikipedia.org/wiki/Symmetric_group#Generators_and_relations
"""
if n == 1:
G = PermutationGroup([Permutation([0])])
elif n == 2:
G = PermutationGroup([Permutation([1, 0])])
else:
a = list(range(1, n))
a.append(0)
gen1 = _af_new(a)
a = list(range(n))
a[0], a[1] = a[1], a[0]
gen2 = _af_new(a)
G = PermutationGroup([gen1, gen2])
set_symmetric_group_properties(G, n, n)
G._is_sym = True
return G
def set_symmetric_group_properties(G, n, degree):
"""Set known properties of a symmetric group. """
if n < 3:
G._is_abelian = True
G._is_nilpotent = True
else:
G._is_abelian = False
G._is_nilpotent = False
if n < 5:
G._is_solvable = True
else:
G._is_solvable = False
G._degree = degree
G._is_transitive = True
G._is_dihedral = (n in [2, 3]) # cf Landau's func and Stirling's approx
def RubikGroup(n):
"""Return a group of Rubik's cube generators
>>> from sympy.combinatorics.named_groups import RubikGroup
>>> RubikGroup(2).is_group
True
"""
from sympy.combinatorics.generators import rubik
if n <= 1:
raise ValueError("Invalid cube. n has to be greater than 1")
return PermutationGroup(rubik(n))
PK ]ZZZn9'�iQ iQ ! sympy/combinatorics/partitions.pyfrom sympy.core import Basic, Dict, sympify, Tuple
from sympy.core.numbers import Integer
from sympy.core.sorting import default_sort_key
from sympy.core.sympify import _sympify
from sympy.functions.combinatorial.numbers import bell
from sympy.matrices import zeros
from sympy.sets.sets import FiniteSet, Union
from sympy.utilities.iterables import flatten, group
from sympy.utilities.misc import as_int
from collections import defaultdict
class Partition(FiniteSet):
"""
This class represents an abstract partition.
A partition is a set of disjoint sets whose union equals a given set.
See Also
========
sympy.utilities.iterables.partitions,
sympy.utilities.iterables.multiset_partitions
"""
_rank = None
_partition = None
def __new__(cls, *partition):
"""
Generates a new partition object.
This method also verifies if the arguments passed are
valid and raises a ValueError if they are not.
Examples
========
Creating Partition from Python lists:
>>> from sympy.combinatorics import Partition
>>> a = Partition([1, 2], [3])
>>> a
Partition({3}, {1, 2})
>>> a.partition
[[1, 2], [3]]
>>> len(a)
2
>>> a.members
(1, 2, 3)
Creating Partition from Python sets:
>>> Partition({1, 2, 3}, {4, 5})
Partition({4, 5}, {1, 2, 3})
Creating Partition from SymPy finite sets:
>>> from sympy import FiniteSet
>>> a = FiniteSet(1, 2, 3)
>>> b = FiniteSet(4, 5)
>>> Partition(a, b)
Partition({4, 5}, {1, 2, 3})
"""
args = []
dups = False
for arg in partition:
if isinstance(arg, list):
as_set = set(arg)
if len(as_set) < len(arg):
dups = True
break # error below
arg = as_set
args.append(_sympify(arg))
if not all(isinstance(part, FiniteSet) for part in args):
raise ValueError(
"Each argument to Partition should be " \
"a list, set, or a FiniteSet")
# sort so we have a canonical reference for RGS
U = Union(*args)
if dups or len(U) < sum(len(arg) for arg in args):
raise ValueError("Partition contained duplicate elements.")
obj = FiniteSet.__new__(cls, *args)
obj.members = tuple(U)
obj.size = len(U)
return obj
def sort_key(self, order=None):
"""Return a canonical key that can be used for sorting.
Ordering is based on the size and sorted elements of the partition
and ties are broken with the rank.
Examples
========
>>> from sympy import default_sort_key
>>> from sympy.combinatorics import Partition
>>> from sympy.abc import x
>>> a = Partition([1, 2])
>>> b = Partition([3, 4])
>>> c = Partition([1, x])
>>> d = Partition(list(range(4)))
>>> l = [d, b, a + 1, a, c]
>>> l.sort(key=default_sort_key); l
[Partition({1, 2}), Partition({1}, {2}), Partition({1, x}), Partition({3, 4}), Partition({0, 1, 2, 3})]
"""
if order is None:
members = self.members
else:
members = tuple(sorted(self.members,
key=lambda w: default_sort_key(w, order)))
return tuple(map(default_sort_key, (self.size, members, self.rank)))
@property
def partition(self):
"""Return partition as a sorted list of lists.
Examples
========
>>> from sympy.combinatorics import Partition
>>> Partition([1], [2, 3]).partition
[[1], [2, 3]]
"""
if self._partition is None:
self._partition = sorted([sorted(p, key=default_sort_key)
for p in self.args])
return self._partition
def __add__(self, other):
"""
Return permutation whose rank is ``other`` greater than current rank,
(mod the maximum rank for the set).
Examples
========
>>> from sympy.combinatorics import Partition
>>> a = Partition([1, 2], [3])
>>> a.rank
1
>>> (a + 1).rank
2
>>> (a + 100).rank
1
"""
other = as_int(other)
offset = self.rank + other
result = RGS_unrank((offset) %
RGS_enum(self.size),
self.size)
return Partition.from_rgs(result, self.members)
def __sub__(self, other):
"""
Return permutation whose rank is ``other`` less than current rank,
(mod the maximum rank for the set).
Examples
========
>>> from sympy.combinatorics import Partition
>>> a = Partition([1, 2], [3])
>>> a.rank
1
>>> (a - 1).rank
0
>>> (a - 100).rank
1
"""
return self.__add__(-other)
def __le__(self, other):
"""
Checks if a partition is less than or equal to
the other based on rank.
Examples
========
>>> from sympy.combinatorics import Partition
>>> a = Partition([1, 2], [3, 4, 5])
>>> b = Partition([1], [2, 3], [4], [5])
>>> a.rank, b.rank
(9, 34)
>>> a <= a
True
>>> a <= b
True
"""
return self.sort_key() <= sympify(other).sort_key()
def __lt__(self, other):
"""
Checks if a partition is less than the other.
Examples
========
>>> from sympy.combinatorics import Partition
>>> a = Partition([1, 2], [3, 4, 5])
>>> b = Partition([1], [2, 3], [4], [5])
>>> a.rank, b.rank
(9, 34)
>>> a < b
True
"""
return self.sort_key() < sympify(other).sort_key()
@property
def rank(self):
"""
Gets the rank of a partition.
Examples
========
>>> from sympy.combinatorics import Partition
>>> a = Partition([1, 2], [3], [4, 5])
>>> a.rank
13
"""
if self._rank is not None:
return self._rank
self._rank = RGS_rank(self.RGS)
return self._rank
@property
def RGS(self):
"""
Returns the "restricted growth string" of the partition.
Explanation
===========
The RGS is returned as a list of indices, L, where L[i] indicates
the block in which element i appears. For example, in a partition
of 3 elements (a, b, c) into 2 blocks ([c], [a, b]) the RGS is
[1, 1, 0]: "a" is in block 1, "b" is in block 1 and "c" is in block 0.
Examples
========
>>> from sympy.combinatorics import Partition
>>> a = Partition([1, 2], [3], [4, 5])
>>> a.members
(1, 2, 3, 4, 5)
>>> a.RGS
(0, 0, 1, 2, 2)
>>> a + 1
Partition({3}, {4}, {5}, {1, 2})
>>> _.RGS
(0, 0, 1, 2, 3)
"""
rgs = {}
partition = self.partition
for i, part in enumerate(partition):
for j in part:
rgs[j] = i
return tuple([rgs[i] for i in sorted(
[i for p in partition for i in p], key=default_sort_key)])
@classmethod
def from_rgs(self, rgs, elements):
"""
Creates a set partition from a restricted growth string.
Explanation
===========
The indices given in rgs are assumed to be the index
of the element as given in elements *as provided* (the
elements are not sorted by this routine). Block numbering
starts from 0. If any block was not referenced in ``rgs``
an error will be raised.
Examples
========
>>> from sympy.combinatorics import Partition
>>> Partition.from_rgs([0, 1, 2, 0, 1], list('abcde'))
Partition({c}, {a, d}, {b, e})
>>> Partition.from_rgs([0, 1, 2, 0, 1], list('cbead'))
Partition({e}, {a, c}, {b, d})
>>> a = Partition([1, 4], [2], [3, 5])
>>> Partition.from_rgs(a.RGS, a.members)
Partition({2}, {1, 4}, {3, 5})
"""
if len(rgs) != len(elements):
raise ValueError('mismatch in rgs and element lengths')
max_elem = max(rgs) + 1
partition = [[] for i in range(max_elem)]
j = 0
for i in rgs:
partition[i].append(elements[j])
j += 1
if not all(p for p in partition):
raise ValueError('some blocks of the partition were empty.')
return Partition(*partition)
class IntegerPartition(Basic):
"""
This class represents an integer partition.
Explanation
===========
In number theory and combinatorics, a partition of a positive integer,
``n``, also called an integer partition, is a way of writing ``n`` as a
list of positive integers that sum to n. Two partitions that differ only
in the order of summands are considered to be the same partition; if order
matters then the partitions are referred to as compositions. For example,
4 has five partitions: [4], [3, 1], [2, 2], [2, 1, 1], and [1, 1, 1, 1];
the compositions [1, 2, 1] and [1, 1, 2] are the same as partition
[2, 1, 1].
See Also
========
sympy.utilities.iterables.partitions,
sympy.utilities.iterables.multiset_partitions
References
==========
.. [1] https://en.wikipedia.org/wiki/Partition_%28number_theory%29
"""
_dict = None
_keys = None
def __new__(cls, partition, integer=None):
"""
Generates a new IntegerPartition object from a list or dictionary.
Explanation
===========
The partition can be given as a list of positive integers or a
dictionary of (integer, multiplicity) items. If the partition is
preceded by an integer an error will be raised if the partition
does not sum to that given integer.
Examples
========
>>> from sympy.combinatorics.partitions import IntegerPartition
>>> a = IntegerPartition([5, 4, 3, 1, 1])
>>> a
IntegerPartition(14, (5, 4, 3, 1, 1))
>>> print(a)
[5, 4, 3, 1, 1]
>>> IntegerPartition({1:3, 2:1})
IntegerPartition(5, (2, 1, 1, 1))
If the value that the partition should sum to is given first, a check
will be made to see n error will be raised if there is a discrepancy:
>>> IntegerPartition(10, [5, 4, 3, 1])
Traceback (most recent call last):
...
ValueError: The partition is not valid
"""
if integer is not None:
integer, partition = partition, integer
if isinstance(partition, (dict, Dict)):
_ = []
for k, v in sorted(partition.items(), reverse=True):
if not v:
continue
k, v = as_int(k), as_int(v)
_.extend([k]*v)
partition = tuple(_)
else:
partition = tuple(sorted(map(as_int, partition), reverse=True))
sum_ok = False
if integer is None:
integer = sum(partition)
sum_ok = True
else:
integer = as_int(integer)
if not sum_ok and sum(partition) != integer:
raise ValueError("Partition did not add to %s" % integer)
if any(i < 1 for i in partition):
raise ValueError("All integer summands must be greater than one")
obj = Basic.__new__(cls, Integer(integer), Tuple(*partition))
obj.partition = list(partition)
obj.integer = integer
return obj
def prev_lex(self):
"""Return the previous partition of the integer, n, in lexical order,
wrapping around to [1, ..., 1] if the partition is [n].
Examples
========
>>> from sympy.combinatorics.partitions import IntegerPartition
>>> p = IntegerPartition([4])
>>> print(p.prev_lex())
[3, 1]
>>> p.partition > p.prev_lex().partition
True
"""
d = defaultdict(int)
d.update(self.as_dict())
keys = self._keys
if keys == [1]:
return IntegerPartition({self.integer: 1})
if keys[-1] != 1:
d[keys[-1]] -= 1
if keys[-1] == 2:
d[1] = 2
else:
d[keys[-1] - 1] = d[1] = 1
else:
d[keys[-2]] -= 1
left = d[1] + keys[-2]
new = keys[-2]
d[1] = 0
while left:
new -= 1
if left - new >= 0:
d[new] += left//new
left -= d[new]*new
return IntegerPartition(self.integer, d)
def next_lex(self):
"""Return the next partition of the integer, n, in lexical order,
wrapping around to [n] if the partition is [1, ..., 1].
Examples
========
>>> from sympy.combinatorics.partitions import IntegerPartition
>>> p = IntegerPartition([3, 1])
>>> print(p.next_lex())
[4]
>>> p.partition < p.next_lex().partition
True
"""
d = defaultdict(int)
d.update(self.as_dict())
key = self._keys
a = key[-1]
if a == self.integer:
d.clear()
d[1] = self.integer
elif a == 1:
if d[a] > 1:
d[a + 1] += 1
d[a] -= 2
else:
b = key[-2]
d[b + 1] += 1
d[1] = (d[b] - 1)*b
d[b] = 0
else:
if d[a] > 1:
if len(key) == 1:
d.clear()
d[a + 1] = 1
d[1] = self.integer - a - 1
else:
a1 = a + 1
d[a1] += 1
d[1] = d[a]*a - a1
d[a] = 0
else:
b = key[-2]
b1 = b + 1
d[b1] += 1
need = d[b]*b + d[a]*a - b1
d[a] = d[b] = 0
d[1] = need
return IntegerPartition(self.integer, d)
def as_dict(self):
"""Return the partition as a dictionary whose keys are the
partition integers and the values are the multiplicity of that
integer.
Examples
========
>>> from sympy.combinatorics.partitions import IntegerPartition
>>> IntegerPartition([1]*3 + [2] + [3]*4).as_dict()
{1: 3, 2: 1, 3: 4}
"""
if self._dict is None:
groups = group(self.partition, multiple=False)
self._keys = [g[0] for g in groups]
self._dict = dict(groups)
return self._dict
@property
def conjugate(self):
"""
Computes the conjugate partition of itself.
Examples
========
>>> from sympy.combinatorics.partitions import IntegerPartition
>>> a = IntegerPartition([6, 3, 3, 2, 1])
>>> a.conjugate
[5, 4, 3, 1, 1, 1]
"""
j = 1
temp_arr = list(self.partition) + [0]
k = temp_arr[0]
b = [0]*k
while k > 0:
while k > temp_arr[j]:
b[k - 1] = j
k -= 1
j += 1
return b
def __lt__(self, other):
"""Return True if self is less than other when the partition
is listed from smallest to biggest.
Examples
========
>>> from sympy.combinatorics.partitions import IntegerPartition
>>> a = IntegerPartition([3, 1])
>>> a < a
False
>>> b = a.next_lex()
>>> a < b
True
>>> a == b
False
"""
return list(reversed(self.partition)) < list(reversed(other.partition))
def __le__(self, other):
"""Return True if self is less than other when the partition
is listed from smallest to biggest.
Examples
========
>>> from sympy.combinatorics.partitions import IntegerPartition
>>> a = IntegerPartition([4])
>>> a <= a
True
"""
return list(reversed(self.partition)) <= list(reversed(other.partition))
def as_ferrers(self, char='#'):
"""
Prints the ferrer diagram of a partition.
Examples
========
>>> from sympy.combinatorics.partitions import IntegerPartition
>>> print(IntegerPartition([1, 1, 5]).as_ferrers())
#####
#
#
"""
return "\n".join([char*i for i in self.partition])
def __str__(self):
return str(list(self.partition))
def random_integer_partition(n, seed=None):
"""
Generates a random integer partition summing to ``n`` as a list
of reverse-sorted integers.
Examples
========
>>> from sympy.combinatorics.partitions import random_integer_partition
For the following, a seed is given so a known value can be shown; in
practice, the seed would not be given.
>>> random_integer_partition(100, seed=[1, 1, 12, 1, 2, 1, 85, 1])
[85, 12, 2, 1]
>>> random_integer_partition(10, seed=[1, 2, 3, 1, 5, 1])
[5, 3, 1, 1]
>>> random_integer_partition(1)
[1]
"""
from sympy.core.random import _randint
n = as_int(n)
if n < 1:
raise ValueError('n must be a positive integer')
randint = _randint(seed)
partition = []
while (n > 0):
k = randint(1, n)
mult = randint(1, n//k)
partition.append((k, mult))
n -= k*mult
partition.sort(reverse=True)
partition = flatten([[k]*m for k, m in partition])
return partition
def RGS_generalized(m):
"""
Computes the m + 1 generalized unrestricted growth strings
and returns them as rows in matrix.
Examples
========
>>> from sympy.combinatorics.partitions import RGS_generalized
>>> RGS_generalized(6)
Matrix([
[ 1, 1, 1, 1, 1, 1, 1],
[ 1, 2, 3, 4, 5, 6, 0],
[ 2, 5, 10, 17, 26, 0, 0],
[ 5, 15, 37, 77, 0, 0, 0],
[ 15, 52, 151, 0, 0, 0, 0],
[ 52, 203, 0, 0, 0, 0, 0],
[203, 0, 0, 0, 0, 0, 0]])
"""
d = zeros(m + 1)
for i in range(m + 1):
d[0, i] = 1
for i in range(1, m + 1):
for j in range(m):
if j <= m - i:
d[i, j] = j * d[i - 1, j] + d[i - 1, j + 1]
else:
d[i, j] = 0
return d
def RGS_enum(m):
"""
RGS_enum computes the total number of restricted growth strings
possible for a superset of size m.
Examples
========
>>> from sympy.combinatorics.partitions import RGS_enum
>>> from sympy.combinatorics import Partition
>>> RGS_enum(4)
15
>>> RGS_enum(5)
52
>>> RGS_enum(6)
203
We can check that the enumeration is correct by actually generating
the partitions. Here, the 15 partitions of 4 items are generated:
>>> a = Partition(list(range(4)))
>>> s = set()
>>> for i in range(20):
... s.add(a)
... a += 1
...
>>> assert len(s) == 15
"""
if (m < 1):
return 0
elif (m == 1):
return 1
else:
return bell(m)
def RGS_unrank(rank, m):
"""
Gives the unranked restricted growth string for a given
superset size.
Examples
========
>>> from sympy.combinatorics.partitions import RGS_unrank
>>> RGS_unrank(14, 4)
[0, 1, 2, 3]
>>> RGS_unrank(0, 4)
[0, 0, 0, 0]
"""
if m < 1:
raise ValueError("The superset size must be >= 1")
if rank < 0 or RGS_enum(m) <= rank:
raise ValueError("Invalid arguments")
L = [1] * (m + 1)
j = 1
D = RGS_generalized(m)
for i in range(2, m + 1):
v = D[m - i, j]
cr = j*v
if cr <= rank:
L[i] = j + 1
rank -= cr
j += 1
else:
L[i] = int(rank / v + 1)
rank %= v
return [x - 1 for x in L[1:]]
def RGS_rank(rgs):
"""
Computes the rank of a restricted growth string.
Examples
========
>>> from sympy.combinatorics.partitions import RGS_rank, RGS_unrank
>>> RGS_rank([0, 1, 2, 1, 3])
42
>>> RGS_rank(RGS_unrank(4, 7))
4
"""
rgs_size = len(rgs)
rank = 0
D = RGS_generalized(rgs_size)
for i in range(1, rgs_size):
n = len(rgs[(i + 1):])
m = max(rgs[0:i])
rank += D[n, m + 1] * rgs[i]
return rank
PK ]ZZZG�*gS gS sympy/combinatorics/pc_groups.pyfrom sympy.ntheory.primetest import isprime
from sympy.combinatorics.perm_groups import PermutationGroup
from sympy.printing.defaults import DefaultPrinting
from sympy.combinatorics.free_groups import free_group
class PolycyclicGroup(DefaultPrinting):
is_group = True
is_solvable = True
def __init__(self, pc_sequence, pc_series, relative_order, collector=None):
"""
Parameters
==========
pc_sequence : list
A sequence of elements whose classes generate the cyclic factor
groups of pc_series.
pc_series : list
A subnormal sequence of subgroups where each factor group is cyclic.
relative_order : list
The orders of factor groups of pc_series.
collector : Collector
By default, it is None. Collector class provides the
polycyclic presentation with various other functionalities.
"""
self.pcgs = pc_sequence
self.pc_series = pc_series
self.relative_order = relative_order
self.collector = Collector(self.pcgs, pc_series, relative_order) if not collector else collector
def is_prime_order(self):
return all(isprime(order) for order in self.relative_order)
def length(self):
return len(self.pcgs)
class Collector(DefaultPrinting):
"""
References
==========
.. [1] Holt, D., Eick, B., O'Brien, E.
"Handbook of Computational Group Theory"
Section 8.1.3
"""
def __init__(self, pcgs, pc_series, relative_order, free_group_=None, pc_presentation=None):
"""
Most of the parameters for the Collector class are the same as for PolycyclicGroup.
Others are described below.
Parameters
==========
free_group_ : tuple
free_group_ provides the mapping of polycyclic generating
sequence with the free group elements.
pc_presentation : dict
Provides the presentation of polycyclic groups with the
help of power and conjugate relators.
See Also
========
PolycyclicGroup
"""
self.pcgs = pcgs
self.pc_series = pc_series
self.relative_order = relative_order
self.free_group = free_group('x:{}'.format(len(pcgs)))[0] if not free_group_ else free_group_
self.index = {s: i for i, s in enumerate(self.free_group.symbols)}
self.pc_presentation = self.pc_relators()
def minimal_uncollected_subword(self, word):
r"""
Returns the minimal uncollected subwords.
Explanation
===========
A word ``v`` defined on generators in ``X`` is a minimal
uncollected subword of the word ``w`` if ``v`` is a subword
of ``w`` and it has one of the following form
* `v = {x_{i+1}}^{a_j}x_i`
* `v = {x_{i+1}}^{a_j}{x_i}^{-1}`
* `v = {x_i}^{a_j}`
for `a_j` not in `\{1, \ldots, s-1\}`. Where, ``s`` is the power
exponent of the corresponding generator.
Examples
========
>>> from sympy.combinatorics.named_groups import SymmetricGroup
>>> from sympy.combinatorics import free_group
>>> G = SymmetricGroup(4)
>>> PcGroup = G.polycyclic_group()
>>> collector = PcGroup.collector
>>> F, x1, x2 = free_group("x1, x2")
>>> word = x2**2*x1**7
>>> collector.minimal_uncollected_subword(word)
((x2, 2),)
"""
# To handle the case word = <identity>
if not word:
return None
array = word.array_form
re = self.relative_order
index = self.index
for i in range(len(array)):
s1, e1 = array[i]
if re[index[s1]] and (e1 < 0 or e1 > re[index[s1]]-1):
return ((s1, e1), )
for i in range(len(array)-1):
s1, e1 = array[i]
s2, e2 = array[i+1]
if index[s1] > index[s2]:
e = 1 if e2 > 0 else -1
return ((s1, e1), (s2, e))
return None
def relations(self):
"""
Separates the given relators of pc presentation in power and
conjugate relations.
Returns
=======
(power_rel, conj_rel)
Separates pc presentation into power and conjugate relations.
Examples
========
>>> from sympy.combinatorics.named_groups import SymmetricGroup
>>> G = SymmetricGroup(3)
>>> PcGroup = G.polycyclic_group()
>>> collector = PcGroup.collector
>>> power_rel, conj_rel = collector.relations()
>>> power_rel
{x0**2: (), x1**3: ()}
>>> conj_rel
{x0**-1*x1*x0: x1**2}
See Also
========
pc_relators
"""
power_relators = {}
conjugate_relators = {}
for key, value in self.pc_presentation.items():
if len(key.array_form) == 1:
power_relators[key] = value
else:
conjugate_relators[key] = value
return power_relators, conjugate_relators
def subword_index(self, word, w):
"""
Returns the start and ending index of a given
subword in a word.
Parameters
==========
word : FreeGroupElement
word defined on free group elements for a
polycyclic group.
w : FreeGroupElement
subword of a given word, whose starting and
ending index to be computed.
Returns
=======
(i, j)
A tuple containing starting and ending index of ``w``
in the given word.
Examples
========
>>> from sympy.combinatorics.named_groups import SymmetricGroup
>>> from sympy.combinatorics import free_group
>>> G = SymmetricGroup(4)
>>> PcGroup = G.polycyclic_group()
>>> collector = PcGroup.collector
>>> F, x1, x2 = free_group("x1, x2")
>>> word = x2**2*x1**7
>>> w = x2**2*x1
>>> collector.subword_index(word, w)
(0, 3)
>>> w = x1**7
>>> collector.subword_index(word, w)
(2, 9)
"""
low = -1
high = -1
for i in range(len(word)-len(w)+1):
if word.subword(i, i+len(w)) == w:
low = i
high = i+len(w)
break
if low == high == -1:
return -1, -1
return low, high
def map_relation(self, w):
"""
Return a conjugate relation.
Explanation
===========
Given a word formed by two free group elements, the
corresponding conjugate relation with those free
group elements is formed and mapped with the collected
word in the polycyclic presentation.
Examples
========
>>> from sympy.combinatorics.named_groups import SymmetricGroup
>>> from sympy.combinatorics import free_group
>>> G = SymmetricGroup(3)
>>> PcGroup = G.polycyclic_group()
>>> collector = PcGroup.collector
>>> F, x0, x1 = free_group("x0, x1")
>>> w = x1*x0
>>> collector.map_relation(w)
x1**2
See Also
========
pc_presentation
"""
array = w.array_form
s1 = array[0][0]
s2 = array[1][0]
key = ((s2, -1), (s1, 1), (s2, 1))
key = self.free_group.dtype(key)
return self.pc_presentation[key]
def collected_word(self, word):
r"""
Return the collected form of a word.
Explanation
===========
A word ``w`` is called collected, if `w = {x_{i_1}}^{a_1} * \ldots *
{x_{i_r}}^{a_r}` with `i_1 < i_2< \ldots < i_r` and `a_j` is in
`\{1, \ldots, {s_j}-1\}`.
Otherwise w is uncollected.
Parameters
==========
word : FreeGroupElement
An uncollected word.
Returns
=======
word
A collected word of form `w = {x_{i_1}}^{a_1}, \ldots,
{x_{i_r}}^{a_r}` with `i_1, i_2, \ldots, i_r` and `a_j \in
\{1, \ldots, {s_j}-1\}`.
Examples
========
>>> from sympy.combinatorics.named_groups import SymmetricGroup
>>> from sympy.combinatorics.perm_groups import PermutationGroup
>>> from sympy.combinatorics import free_group
>>> G = SymmetricGroup(4)
>>> PcGroup = G.polycyclic_group()
>>> collector = PcGroup.collector
>>> F, x0, x1, x2, x3 = free_group("x0, x1, x2, x3")
>>> word = x3*x2*x1*x0
>>> collected_word = collector.collected_word(word)
>>> free_to_perm = {}
>>> free_group = collector.free_group
>>> for sym, gen in zip(free_group.symbols, collector.pcgs):
... free_to_perm[sym] = gen
>>> G1 = PermutationGroup()
>>> for w in word:
... sym = w[0]
... perm = free_to_perm[sym]
... G1 = PermutationGroup([perm] + G1.generators)
>>> G2 = PermutationGroup()
>>> for w in collected_word:
... sym = w[0]
... perm = free_to_perm[sym]
... G2 = PermutationGroup([perm] + G2.generators)
The two are not identical, but they are equivalent:
>>> G1.equals(G2), G1 == G2
(True, False)
See Also
========
minimal_uncollected_subword
"""
free_group = self.free_group
while True:
w = self.minimal_uncollected_subword(word)
if not w:
break
low, high = self.subword_index(word, free_group.dtype(w))
if low == -1:
continue
s1, e1 = w[0]
if len(w) == 1:
re = self.relative_order[self.index[s1]]
q = e1 // re
r = e1-q*re
key = ((w[0][0], re), )
key = free_group.dtype(key)
if self.pc_presentation[key]:
presentation = self.pc_presentation[key].array_form
sym, exp = presentation[0]
word_ = ((w[0][0], r), (sym, q*exp))
word_ = free_group.dtype(word_)
else:
if r != 0:
word_ = ((w[0][0], r), )
word_ = free_group.dtype(word_)
else:
word_ = None
word = word.eliminate_word(free_group.dtype(w), word_)
if len(w) == 2 and w[1][1] > 0:
s2, e2 = w[1]
s2 = ((s2, 1), )
s2 = free_group.dtype(s2)
word_ = self.map_relation(free_group.dtype(w))
word_ = s2*word_**e1
word_ = free_group.dtype(word_)
word = word.substituted_word(low, high, word_)
elif len(w) == 2 and w[1][1] < 0:
s2, e2 = w[1]
s2 = ((s2, 1), )
s2 = free_group.dtype(s2)
word_ = self.map_relation(free_group.dtype(w))
word_ = s2**-1*word_**e1
word_ = free_group.dtype(word_)
word = word.substituted_word(low, high, word_)
return word
def pc_relators(self):
r"""
Return the polycyclic presentation.
Explanation
===========
There are two types of relations used in polycyclic
presentation.
* Power relations : Power relators are of the form `x_i^{re_i}`,
where `i \in \{0, \ldots, \mathrm{len(pcgs)}\}`, ``x`` represents polycyclic
generator and ``re`` is the corresponding relative order.
* Conjugate relations : Conjugate relators are of the form `x_j^-1x_ix_j`,
where `j < i \in \{0, \ldots, \mathrm{len(pcgs)}\}`.
Returns
=======
A dictionary with power and conjugate relations as key and
their collected form as corresponding values.
Notes
=====
Identity Permutation is mapped with empty ``()``.
Examples
========
>>> from sympy.combinatorics.named_groups import SymmetricGroup
>>> from sympy.combinatorics.permutations import Permutation
>>> S = SymmetricGroup(49).sylow_subgroup(7)
>>> der = S.derived_series()
>>> G = der[len(der)-2]
>>> PcGroup = G.polycyclic_group()
>>> collector = PcGroup.collector
>>> pcgs = PcGroup.pcgs
>>> len(pcgs)
6
>>> free_group = collector.free_group
>>> pc_resentation = collector.pc_presentation
>>> free_to_perm = {}
>>> for s, g in zip(free_group.symbols, pcgs):
... free_to_perm[s] = g
>>> for k, v in pc_resentation.items():
... k_array = k.array_form
... if v != ():
... v_array = v.array_form
... lhs = Permutation()
... for gen in k_array:
... s = gen[0]
... e = gen[1]
... lhs = lhs*free_to_perm[s]**e
... if v == ():
... assert lhs.is_identity
... continue
... rhs = Permutation()
... for gen in v_array:
... s = gen[0]
... e = gen[1]
... rhs = rhs*free_to_perm[s]**e
... assert lhs == rhs
"""
free_group = self.free_group
rel_order = self.relative_order
pc_relators = {}
perm_to_free = {}
pcgs = self.pcgs
for gen, s in zip(pcgs, free_group.generators):
perm_to_free[gen**-1] = s**-1
perm_to_free[gen] = s
pcgs = pcgs[::-1]
series = self.pc_series[::-1]
rel_order = rel_order[::-1]
collected_gens = []
for i, gen in enumerate(pcgs):
re = rel_order[i]
relation = perm_to_free[gen]**re
G = series[i]
l = G.generator_product(gen**re, original = True)
l.reverse()
word = free_group.identity
for g in l:
word = word*perm_to_free[g]
word = self.collected_word(word)
pc_relators[relation] = word if word else ()
self.pc_presentation = pc_relators
collected_gens.append(gen)
if len(collected_gens) > 1:
conj = collected_gens[len(collected_gens)-1]
conjugator = perm_to_free[conj]
for j in range(len(collected_gens)-1):
conjugated = perm_to_free[collected_gens[j]]
relation = conjugator**-1*conjugated*conjugator
gens = conj**-1*collected_gens[j]*conj
l = G.generator_product(gens, original = True)
l.reverse()
word = free_group.identity
for g in l:
word = word*perm_to_free[g]
word = self.collected_word(word)
pc_relators[relation] = word if word else ()
self.pc_presentation = pc_relators
return pc_relators
def exponent_vector(self, element):
r"""
Return the exponent vector of length equal to the
length of polycyclic generating sequence.
Explanation
===========
For a given generator/element ``g`` of the polycyclic group,
it can be represented as `g = {x_1}^{e_1}, \ldots, {x_n}^{e_n}`,
where `x_i` represents polycyclic generators and ``n`` is
the number of generators in the free_group equal to the length
of pcgs.
Parameters
==========
element : Permutation
Generator of a polycyclic group.
Examples
========
>>> from sympy.combinatorics.named_groups import SymmetricGroup
>>> from sympy.combinatorics.permutations import Permutation
>>> G = SymmetricGroup(4)
>>> PcGroup = G.polycyclic_group()
>>> collector = PcGroup.collector
>>> pcgs = PcGroup.pcgs
>>> collector.exponent_vector(G[0])
[1, 0, 0, 0]
>>> exp = collector.exponent_vector(G[1])
>>> g = Permutation()
>>> for i in range(len(exp)):
... g = g*pcgs[i]**exp[i] if exp[i] else g
>>> assert g == G[1]
References
==========
.. [1] Holt, D., Eick, B., O'Brien, E.
"Handbook of Computational Group Theory"
Section 8.1.1, Definition 8.4
"""
free_group = self.free_group
G = PermutationGroup()
for g in self.pcgs:
G = PermutationGroup([g] + G.generators)
gens = G.generator_product(element, original = True)
gens.reverse()
perm_to_free = {}
for sym, g in zip(free_group.generators, self.pcgs):
perm_to_free[g**-1] = sym**-1
perm_to_free[g] = sym
w = free_group.identity
for g in gens:
w = w*perm_to_free[g]
word = self.collected_word(w)
index = self.index
exp_vector = [0]*len(free_group)
word = word.array_form
for t in word:
exp_vector[index[t[0]]] = t[1]
return exp_vector
def depth(self, element):
r"""
Return the depth of a given element.
Explanation
===========
The depth of a given element ``g`` is defined by
`\mathrm{dep}[g] = i` if `e_1 = e_2 = \ldots = e_{i-1} = 0`
and `e_i != 0`, where ``e`` represents the exponent-vector.
Examples
========
>>> from sympy.combinatorics.named_groups import SymmetricGroup
>>> G = SymmetricGroup(3)
>>> PcGroup = G.polycyclic_group()
>>> collector = PcGroup.collector
>>> collector.depth(G[0])
2
>>> collector.depth(G[1])
1
References
==========
.. [1] Holt, D., Eick, B., O'Brien, E.
"Handbook of Computational Group Theory"
Section 8.1.1, Definition 8.5
"""
exp_vector = self.exponent_vector(element)
return next((i+1 for i, x in enumerate(exp_vector) if x), len(self.pcgs)+1)
def leading_exponent(self, element):
r"""
Return the leading non-zero exponent.
Explanation
===========
The leading exponent for a given element `g` is defined
by `\mathrm{leading\_exponent}[g]` `= e_i`, if `\mathrm{depth}[g] = i`.
Examples
========
>>> from sympy.combinatorics.named_groups import SymmetricGroup
>>> G = SymmetricGroup(3)
>>> PcGroup = G.polycyclic_group()
>>> collector = PcGroup.collector
>>> collector.leading_exponent(G[1])
1
"""
exp_vector = self.exponent_vector(element)
depth = self.depth(element)
if depth != len(self.pcgs)+1:
return exp_vector[depth-1]
return None
def _sift(self, z, g):
h = g
d = self.depth(h)
while d < len(self.pcgs) and z[d-1] != 1:
k = z[d-1]
e = self.leading_exponent(h)*(self.leading_exponent(k))**-1
e = e % self.relative_order[d-1]
h = k**-e*h
d = self.depth(h)
return h
def induced_pcgs(self, gens):
"""
Parameters
==========
gens : list
A list of generators on which polycyclic subgroup
is to be defined.
Examples
========
>>> from sympy.combinatorics.named_groups import SymmetricGroup
>>> S = SymmetricGroup(8)
>>> G = S.sylow_subgroup(2)
>>> PcGroup = G.polycyclic_group()
>>> collector = PcGroup.collector
>>> gens = [G[0], G[1]]
>>> ipcgs = collector.induced_pcgs(gens)
>>> [gen.order() for gen in ipcgs]
[2, 2, 2]
>>> G = S.sylow_subgroup(3)
>>> PcGroup = G.polycyclic_group()
>>> collector = PcGroup.collector
>>> gens = [G[0], G[1]]
>>> ipcgs = collector.induced_pcgs(gens)
>>> [gen.order() for gen in ipcgs]
[3]
"""
z = [1]*len(self.pcgs)
G = gens
while G:
g = G.pop(0)
h = self._sift(z, g)
d = self.depth(h)
if d < len(self.pcgs):
for gen in z:
if gen != 1:
G.append(h**-1*gen**-1*h*gen)
z[d-1] = h;
z = [gen for gen in z if gen != 1]
return z
def constructive_membership_test(self, ipcgs, g):
"""
Return the exponent vector for induced pcgs.
"""
e = [0]*len(ipcgs)
h = g
d = self.depth(h)
for i, gen in enumerate(ipcgs):
while self.depth(gen) == d:
f = self.leading_exponent(h)*self.leading_exponent(gen)
f = f % self.relative_order[d-1]
h = gen**(-f)*h
e[i] = f
d = self.depth(h)
if h == 1:
return e
return False
PK ]ZZZӝp�S� S� " sympy/combinatorics/perm_groups.pyfrom math import factorial as _factorial, log, prod
from itertools import chain, product
from sympy.combinatorics import Permutation
from sympy.combinatorics.permutations import (_af_commutes_with, _af_invert,
_af_rmul, _af_rmuln, _af_pow, Cycle)
from sympy.combinatorics.util import (_check_cycles_alt_sym,
_distribute_gens_by_base, _orbits_transversals_from_bsgs,
_handle_precomputed_bsgs, _base_ordering, _strong_gens_from_distr,
_strip, _strip_af)
from sympy.core import Basic
from sympy.core.random import _randrange, randrange, choice
from sympy.core.symbol import Symbol
from sympy.core.sympify import _sympify
from sympy.functions.combinatorial.factorials import factorial
from sympy.ntheory import primefactors, sieve
from sympy.ntheory.factor_ import (factorint, multiplicity)
from sympy.ntheory.primetest import isprime
from sympy.utilities.iterables import has_variety, is_sequence, uniq
rmul = Permutation.rmul_with_af
_af_new = Permutation._af_new
class PermutationGroup(Basic):
r"""The class defining a Permutation group.
Explanation
===========
``PermutationGroup([p1, p2, ..., pn])`` returns the permutation group
generated by the list of permutations. This group can be supplied
to Polyhedron if one desires to decorate the elements to which the
indices of the permutation refer.
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> from sympy.combinatorics import Polyhedron
The permutations corresponding to motion of the front, right and
bottom face of a $2 \times 2$ Rubik's cube are defined:
>>> F = Permutation(2, 19, 21, 8)(3, 17, 20, 10)(4, 6, 7, 5)
>>> R = Permutation(1, 5, 21, 14)(3, 7, 23, 12)(8, 10, 11, 9)
>>> D = Permutation(6, 18, 14, 10)(7, 19, 15, 11)(20, 22, 23, 21)
These are passed as permutations to PermutationGroup:
>>> G = PermutationGroup(F, R, D)
>>> G.order()
3674160
The group can be supplied to a Polyhedron in order to track the
objects being moved. An example involving the $2 \times 2$ Rubik's cube is
given there, but here is a simple demonstration:
>>> a = Permutation(2, 1)
>>> b = Permutation(1, 0)
>>> G = PermutationGroup(a, b)
>>> P = Polyhedron(list('ABC'), pgroup=G)
>>> P.corners
(A, B, C)
>>> P.rotate(0) # apply permutation 0
>>> P.corners
(A, C, B)
>>> P.reset()
>>> P.corners
(A, B, C)
Or one can make a permutation as a product of selected permutations
and apply them to an iterable directly:
>>> P10 = G.make_perm([0, 1])
>>> P10('ABC')
['C', 'A', 'B']
See Also
========
sympy.combinatorics.polyhedron.Polyhedron,
sympy.combinatorics.permutations.Permutation
References
==========
.. [1] Holt, D., Eick, B., O'Brien, E.
"Handbook of Computational Group Theory"
.. [2] Seress, A.
"Permutation Group Algorithms"
.. [3] https://en.wikipedia.org/wiki/Schreier_vector
.. [4] https://en.wikipedia.org/wiki/Nielsen_transformation#Product_replacement_algorithm
.. [5] Frank Celler, Charles R.Leedham-Green, Scott H.Murray,
Alice C.Niemeyer, and E.A.O'Brien. "Generating Random
Elements of a Finite Group"
.. [6] https://en.wikipedia.org/wiki/Block_%28permutation_group_theory%29
.. [7] https://algorithmist.com/wiki/Union_find
.. [8] https://en.wikipedia.org/wiki/Multiply_transitive_group#Multiply_transitive_groups
.. [9] https://en.wikipedia.org/wiki/Center_%28group_theory%29
.. [10] https://en.wikipedia.org/wiki/Centralizer_and_normalizer
.. [11] https://groupprops.subwiki.org/wiki/Derived_subgroup
.. [12] https://en.wikipedia.org/wiki/Nilpotent_group
.. [13] https://www.math.colostate.edu/~hulpke/CGT/cgtnotes.pdf
.. [14] https://docs.gap-system.org/doc/ref/manual.pdf
"""
is_group = True
def __new__(cls, *args, dups=True, **kwargs):
"""The default constructor. Accepts Cycle and Permutation forms.
Removes duplicates unless ``dups`` keyword is ``False``.
"""
if not args:
args = [Permutation()]
else:
args = list(args[0] if is_sequence(args[0]) else args)
if not args:
args = [Permutation()]
if any(isinstance(a, Cycle) for a in args):
args = [Permutation(a) for a in args]
if has_variety(a.size for a in args):
degree = kwargs.pop('degree', None)
if degree is None:
degree = max(a.size for a in args)
for i in range(len(args)):
if args[i].size != degree:
args[i] = Permutation(args[i], size=degree)
if dups:
args = list(uniq([_af_new(list(a)) for a in args]))
if len(args) > 1:
args = [g for g in args if not g.is_identity]
return Basic.__new__(cls, *args, **kwargs)
def __init__(self, *args, **kwargs):
self._generators = list(self.args)
self._order = None
self._elements = []
self._center = None
self._is_abelian = None
self._is_transitive = None
self._is_sym = None
self._is_alt = None
self._is_primitive = None
self._is_nilpotent = None
self._is_solvable = None
self._is_trivial = None
self._transitivity_degree = None
self._max_div = None
self._is_perfect = None
self._is_cyclic = None
self._is_dihedral = None
self._r = len(self._generators)
self._degree = self._generators[0].size
# these attributes are assigned after running schreier_sims
self._base = []
self._strong_gens = []
self._strong_gens_slp = []
self._basic_orbits = []
self._transversals = []
self._transversal_slp = []
# these attributes are assigned after running _random_pr_init
self._random_gens = []
# finite presentation of the group as an instance of `FpGroup`
self._fp_presentation = None
def __getitem__(self, i):
return self._generators[i]
def __contains__(self, i):
"""Return ``True`` if *i* is contained in PermutationGroup.
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> p = Permutation(1, 2, 3)
>>> Permutation(3) in PermutationGroup(p)
True
"""
if not isinstance(i, Permutation):
raise TypeError("A PermutationGroup contains only Permutations as "
"elements, not elements of type %s" % type(i))
return self.contains(i)
def __len__(self):
return len(self._generators)
def equals(self, other):
"""Return ``True`` if PermutationGroup generated by elements in the
group are same i.e they represent the same PermutationGroup.
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> p = Permutation(0, 1, 2, 3, 4, 5)
>>> G = PermutationGroup([p, p**2])
>>> H = PermutationGroup([p**2, p])
>>> G.generators == H.generators
False
>>> G.equals(H)
True
"""
if not isinstance(other, PermutationGroup):
return False
set_self_gens = set(self.generators)
set_other_gens = set(other.generators)
# before reaching the general case there are also certain
# optimisation and obvious cases requiring less or no actual
# computation.
if set_self_gens == set_other_gens:
return True
# in the most general case it will check that each generator of
# one group belongs to the other PermutationGroup and vice-versa
for gen1 in set_self_gens:
if not other.contains(gen1):
return False
for gen2 in set_other_gens:
if not self.contains(gen2):
return False
return True
def __mul__(self, other):
"""
Return the direct product of two permutation groups as a permutation
group.
Explanation
===========
This implementation realizes the direct product by shifting the index
set for the generators of the second group: so if we have ``G`` acting
on ``n1`` points and ``H`` acting on ``n2`` points, ``G*H`` acts on
``n1 + n2`` points.
Examples
========
>>> from sympy.combinatorics.named_groups import CyclicGroup
>>> G = CyclicGroup(5)
>>> H = G*G
>>> H
PermutationGroup([
(9)(0 1 2 3 4),
(5 6 7 8 9)])
>>> H.order()
25
"""
if isinstance(other, Permutation):
return Coset(other, self, dir='+')
gens1 = [perm._array_form for perm in self.generators]
gens2 = [perm._array_form for perm in other.generators]
n1 = self._degree
n2 = other._degree
start = list(range(n1))
end = list(range(n1, n1 + n2))
for i in range(len(gens2)):
gens2[i] = [x + n1 for x in gens2[i]]
gens2 = [start + gen for gen in gens2]
gens1 = [gen + end for gen in gens1]
together = gens1 + gens2
gens = [_af_new(x) for x in together]
return PermutationGroup(gens)
def _random_pr_init(self, r, n, _random_prec_n=None):
r"""Initialize random generators for the product replacement algorithm.
Explanation
===========
The implementation uses a modification of the original product
replacement algorithm due to Leedham-Green, as described in [1],
pp. 69-71; also, see [2], pp. 27-29 for a detailed theoretical
analysis of the original product replacement algorithm, and [4].
The product replacement algorithm is used for producing random,
uniformly distributed elements of a group `G` with a set of generators
`S`. For the initialization ``_random_pr_init``, a list ``R`` of
`\max\{r, |S|\}` group generators is created as the attribute
``G._random_gens``, repeating elements of `S` if necessary, and the
identity element of `G` is appended to ``R`` - we shall refer to this
last element as the accumulator. Then the function ``random_pr()``
is called ``n`` times, randomizing the list ``R`` while preserving
the generation of `G` by ``R``. The function ``random_pr()`` itself
takes two random elements ``g, h`` among all elements of ``R`` but
the accumulator and replaces ``g`` with a randomly chosen element
from `\{gh, g(~h), hg, (~h)g\}`. Then the accumulator is multiplied
by whatever ``g`` was replaced by. The new value of the accumulator is
then returned by ``random_pr()``.
The elements returned will eventually (for ``n`` large enough) become
uniformly distributed across `G` ([5]). For practical purposes however,
the values ``n = 50, r = 11`` are suggested in [1].
Notes
=====
THIS FUNCTION HAS SIDE EFFECTS: it changes the attribute
self._random_gens
See Also
========
random_pr
"""
deg = self.degree
random_gens = [x._array_form for x in self.generators]
k = len(random_gens)
if k < r:
for i in range(k, r):
random_gens.append(random_gens[i - k])
acc = list(range(deg))
random_gens.append(acc)
self._random_gens = random_gens
# handle randomized input for testing purposes
if _random_prec_n is None:
for i in range(n):
self.random_pr()
else:
for i in range(n):
self.random_pr(_random_prec=_random_prec_n[i])
def _union_find_merge(self, first, second, ranks, parents, not_rep):
"""Merges two classes in a union-find data structure.
Explanation
===========
Used in the implementation of Atkinson's algorithm as suggested in [1],
pp. 83-87. The class merging process uses union by rank as an
optimization. ([7])
Notes
=====
THIS FUNCTION HAS SIDE EFFECTS: the list of class representatives,
``parents``, the list of class sizes, ``ranks``, and the list of
elements that are not representatives, ``not_rep``, are changed due to
class merging.
See Also
========
minimal_block, _union_find_rep
References
==========
.. [1] Holt, D., Eick, B., O'Brien, E.
"Handbook of computational group theory"
.. [7] https://algorithmist.com/wiki/Union_find
"""
rep_first = self._union_find_rep(first, parents)
rep_second = self._union_find_rep(second, parents)
if rep_first != rep_second:
# union by rank
if ranks[rep_first] >= ranks[rep_second]:
new_1, new_2 = rep_first, rep_second
else:
new_1, new_2 = rep_second, rep_first
total_rank = ranks[new_1] + ranks[new_2]
if total_rank > self.max_div:
return -1
parents[new_2] = new_1
ranks[new_1] = total_rank
not_rep.append(new_2)
return 1
return 0
def _union_find_rep(self, num, parents):
"""Find representative of a class in a union-find data structure.
Explanation
===========
Used in the implementation of Atkinson's algorithm as suggested in [1],
pp. 83-87. After the representative of the class to which ``num``
belongs is found, path compression is performed as an optimization
([7]).
Notes
=====
THIS FUNCTION HAS SIDE EFFECTS: the list of class representatives,
``parents``, is altered due to path compression.
See Also
========
minimal_block, _union_find_merge
References
==========
.. [1] Holt, D., Eick, B., O'Brien, E.
"Handbook of computational group theory"
.. [7] https://algorithmist.com/wiki/Union_find
"""
rep, parent = num, parents[num]
while parent != rep:
rep = parent
parent = parents[rep]
# path compression
temp, parent = num, parents[num]
while parent != rep:
parents[temp] = rep
temp = parent
parent = parents[temp]
return rep
@property
def base(self):
r"""Return a base from the Schreier-Sims algorithm.
Explanation
===========
For a permutation group `G`, a base is a sequence of points
`B = (b_1, b_2, \dots, b_k)` such that no element of `G` apart
from the identity fixes all the points in `B`. The concepts of
a base and strong generating set and their applications are
discussed in depth in [1], pp. 87-89 and [2], pp. 55-57.
An alternative way to think of `B` is that it gives the
indices of the stabilizer cosets that contain more than the
identity permutation.
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> G = PermutationGroup([Permutation(0, 1, 3)(2, 4)])
>>> G.base
[0, 2]
See Also
========
strong_gens, basic_transversals, basic_orbits, basic_stabilizers
"""
if self._base == []:
self.schreier_sims()
return self._base
def baseswap(self, base, strong_gens, pos, randomized=False,
transversals=None, basic_orbits=None, strong_gens_distr=None):
r"""Swap two consecutive base points in base and strong generating set.
Explanation
===========
If a base for a group `G` is given by `(b_1, b_2, \dots, b_k)`, this
function returns a base `(b_1, b_2, \dots, b_{i+1}, b_i, \dots, b_k)`,
where `i` is given by ``pos``, and a strong generating set relative
to that base. The original base and strong generating set are not
modified.
The randomized version (default) is of Las Vegas type.
Parameters
==========
base, strong_gens
The base and strong generating set.
pos
The position at which swapping is performed.
randomized
A switch between randomized and deterministic version.
transversals
The transversals for the basic orbits, if known.
basic_orbits
The basic orbits, if known.
strong_gens_distr
The strong generators distributed by basic stabilizers, if known.
Returns
=======
(base, strong_gens)
``base`` is the new base, and ``strong_gens`` is a generating set
relative to it.
Examples
========
>>> from sympy.combinatorics.named_groups import SymmetricGroup
>>> from sympy.combinatorics.testutil import _verify_bsgs
>>> from sympy.combinatorics.perm_groups import PermutationGroup
>>> S = SymmetricGroup(4)
>>> S.schreier_sims()
>>> S.base
[0, 1, 2]
>>> base, gens = S.baseswap(S.base, S.strong_gens, 1, randomized=False)
>>> base, gens
([0, 2, 1],
[(0 1 2 3), (3)(0 1), (1 3 2),
(2 3), (1 3)])
check that base, gens is a BSGS
>>> S1 = PermutationGroup(gens)
>>> _verify_bsgs(S1, base, gens)
True
See Also
========
schreier_sims
Notes
=====
The deterministic version of the algorithm is discussed in
[1], pp. 102-103; the randomized version is discussed in [1], p.103, and
[2], p.98. It is of Las Vegas type.
Notice that [1] contains a mistake in the pseudocode and
discussion of BASESWAP: on line 3 of the pseudocode,
`|\beta_{i+1}^{\left\langle T\right\rangle}|` should be replaced by
`|\beta_{i}^{\left\langle T\right\rangle}|`, and the same for the
discussion of the algorithm.
"""
# construct the basic orbits, generators for the stabilizer chain
# and transversal elements from whatever was provided
transversals, basic_orbits, strong_gens_distr = \
_handle_precomputed_bsgs(base, strong_gens, transversals,
basic_orbits, strong_gens_distr)
base_len = len(base)
degree = self.degree
# size of orbit of base[pos] under the stabilizer we seek to insert
# in the stabilizer chain at position pos + 1
size = len(basic_orbits[pos])*len(basic_orbits[pos + 1]) \
//len(_orbit(degree, strong_gens_distr[pos], base[pos + 1]))
# initialize the wanted stabilizer by a subgroup
if pos + 2 > base_len - 1:
T = []
else:
T = strong_gens_distr[pos + 2][:]
# randomized version
if randomized is True:
stab_pos = PermutationGroup(strong_gens_distr[pos])
schreier_vector = stab_pos.schreier_vector(base[pos + 1])
# add random elements of the stabilizer until they generate it
while len(_orbit(degree, T, base[pos])) != size:
new = stab_pos.random_stab(base[pos + 1],
schreier_vector=schreier_vector)
T.append(new)
# deterministic version
else:
Gamma = set(basic_orbits[pos])
Gamma.remove(base[pos])
if base[pos + 1] in Gamma:
Gamma.remove(base[pos + 1])
# add elements of the stabilizer until they generate it by
# ruling out member of the basic orbit of base[pos] along the way
while len(_orbit(degree, T, base[pos])) != size:
gamma = next(iter(Gamma))
x = transversals[pos][gamma]
temp = x._array_form.index(base[pos + 1]) # (~x)(base[pos + 1])
if temp not in basic_orbits[pos + 1]:
Gamma = Gamma - _orbit(degree, T, gamma)
else:
y = transversals[pos + 1][temp]
el = rmul(x, y)
if el(base[pos]) not in _orbit(degree, T, base[pos]):
T.append(el)
Gamma = Gamma - _orbit(degree, T, base[pos])
# build the new base and strong generating set
strong_gens_new_distr = strong_gens_distr[:]
strong_gens_new_distr[pos + 1] = T
base_new = base[:]
base_new[pos], base_new[pos + 1] = base_new[pos + 1], base_new[pos]
strong_gens_new = _strong_gens_from_distr(strong_gens_new_distr)
for gen in T:
if gen not in strong_gens_new:
strong_gens_new.append(gen)
return base_new, strong_gens_new
@property
def basic_orbits(self):
r"""
Return the basic orbits relative to a base and strong generating set.
Explanation
===========
If `(b_1, b_2, \dots, b_k)` is a base for a group `G`, and
`G^{(i)} = G_{b_1, b_2, \dots, b_{i-1}}` is the ``i``-th basic stabilizer
(so that `G^{(1)} = G`), the ``i``-th basic orbit relative to this base
is the orbit of `b_i` under `G^{(i)}`. See [1], pp. 87-89 for more
information.
Examples
========
>>> from sympy.combinatorics.named_groups import SymmetricGroup
>>> S = SymmetricGroup(4)
>>> S.basic_orbits
[[0, 1, 2, 3], [1, 2, 3], [2, 3]]
See Also
========
base, strong_gens, basic_transversals, basic_stabilizers
"""
if self._basic_orbits == []:
self.schreier_sims()
return self._basic_orbits
@property
def basic_stabilizers(self):
r"""
Return a chain of stabilizers relative to a base and strong generating
set.
Explanation
===========
The ``i``-th basic stabilizer `G^{(i)}` relative to a base
`(b_1, b_2, \dots, b_k)` is `G_{b_1, b_2, \dots, b_{i-1}}`. For more
information, see [1], pp. 87-89.
Examples
========
>>> from sympy.combinatorics.named_groups import AlternatingGroup
>>> A = AlternatingGroup(4)
>>> A.schreier_sims()
>>> A.base
[0, 1]
>>> for g in A.basic_stabilizers:
... print(g)
...
PermutationGroup([
(3)(0 1 2),
(1 2 3)])
PermutationGroup([
(1 2 3)])
See Also
========
base, strong_gens, basic_orbits, basic_transversals
"""
if self._transversals == []:
self.schreier_sims()
strong_gens = self._strong_gens
base = self._base
if not base: # e.g. if self is trivial
return []
strong_gens_distr = _distribute_gens_by_base(base, strong_gens)
basic_stabilizers = []
for gens in strong_gens_distr:
basic_stabilizers.append(PermutationGroup(gens))
return basic_stabilizers
@property
def basic_transversals(self):
"""
Return basic transversals relative to a base and strong generating set.
Explanation
===========
The basic transversals are transversals of the basic orbits. They
are provided as a list of dictionaries, each dictionary having
keys - the elements of one of the basic orbits, and values - the
corresponding transversal elements. See [1], pp. 87-89 for more
information.
Examples
========
>>> from sympy.combinatorics.named_groups import AlternatingGroup
>>> A = AlternatingGroup(4)
>>> A.basic_transversals
[{0: (3), 1: (3)(0 1 2), 2: (3)(0 2 1), 3: (0 3 1)}, {1: (3), 2: (1 2 3), 3: (1 3 2)}]
See Also
========
strong_gens, base, basic_orbits, basic_stabilizers
"""
if self._transversals == []:
self.schreier_sims()
return self._transversals
def composition_series(self):
r"""
Return the composition series for a group as a list
of permutation groups.
Explanation
===========
The composition series for a group `G` is defined as a
subnormal series `G = H_0 > H_1 > H_2 \ldots` A composition
series is a subnormal series such that each factor group
`H(i+1) / H(i)` is simple.
A subnormal series is a composition series only if it is of
maximum length.
The algorithm works as follows:
Starting with the derived series the idea is to fill
the gap between `G = der[i]` and `H = der[i+1]` for each
`i` independently. Since, all subgroups of the abelian group
`G/H` are normal so, first step is to take the generators
`g` of `G` and add them to generators of `H` one by one.
The factor groups formed are not simple in general. Each
group is obtained from the previous one by adding one
generator `g`, if the previous group is denoted by `H`
then the next group `K` is generated by `g` and `H`.
The factor group `K/H` is cyclic and it's order is
`K.order()//G.order()`. The series is then extended between
`K` and `H` by groups generated by powers of `g` and `H`.
The series formed is then prepended to the already existing
series.
Examples
========
>>> from sympy.combinatorics.named_groups import SymmetricGroup
>>> from sympy.combinatorics.named_groups import CyclicGroup
>>> S = SymmetricGroup(12)
>>> G = S.sylow_subgroup(2)
>>> C = G.composition_series()
>>> [H.order() for H in C]
[1024, 512, 256, 128, 64, 32, 16, 8, 4, 2, 1]
>>> G = S.sylow_subgroup(3)
>>> C = G.composition_series()
>>> [H.order() for H in C]
[243, 81, 27, 9, 3, 1]
>>> G = CyclicGroup(12)
>>> C = G.composition_series()
>>> [H.order() for H in C]
[12, 6, 3, 1]
"""
der = self.derived_series()
if not all(g.is_identity for g in der[-1].generators):
raise NotImplementedError('Group should be solvable')
series = []
for i in range(len(der)-1):
H = der[i+1]
up_seg = []
for g in der[i].generators:
K = PermutationGroup([g] + H.generators)
order = K.order() // H.order()
down_seg = []
for p, e in factorint(order).items():
for _ in range(e):
down_seg.append(PermutationGroup([g] + H.generators))
g = g**p
up_seg = down_seg + up_seg
H = K
up_seg[0] = der[i]
series.extend(up_seg)
series.append(der[-1])
return series
def coset_transversal(self, H):
"""Return a transversal of the right cosets of self by its subgroup H
using the second method described in [1], Subsection 4.6.7
"""
if not H.is_subgroup(self):
raise ValueError("The argument must be a subgroup")
if H.order() == 1:
return self.elements
self._schreier_sims(base=H.base) # make G.base an extension of H.base
base = self.base
base_ordering = _base_ordering(base, self.degree)
identity = Permutation(self.degree - 1)
transversals = self.basic_transversals[:]
# transversals is a list of dictionaries. Get rid of the keys
# so that it is a list of lists and sort each list in
# the increasing order of base[l]^x
for l, t in enumerate(transversals):
transversals[l] = sorted(t.values(),
key = lambda x: base_ordering[base[l]^x])
orbits = H.basic_orbits
h_stabs = H.basic_stabilizers
g_stabs = self.basic_stabilizers
indices = [x.order()//y.order() for x, y in zip(g_stabs, h_stabs)]
# T^(l) should be a right transversal of H^(l) in G^(l) for
# 1<=l<=len(base). While H^(l) is the trivial group, T^(l)
# contains all the elements of G^(l) so we might just as well
# start with l = len(h_stabs)-1
if len(g_stabs) > len(h_stabs):
T = g_stabs[len(h_stabs)].elements
else:
T = [identity]
l = len(h_stabs)-1
t_len = len(T)
while l > -1:
T_next = []
for u in transversals[l]:
if u == identity:
continue
b = base_ordering[base[l]^u]
for t in T:
p = t*u
if all(base_ordering[h^p] >= b for h in orbits[l]):
T_next.append(p)
if t_len + len(T_next) == indices[l]:
break
if t_len + len(T_next) == indices[l]:
break
T += T_next
t_len += len(T_next)
l -= 1
T.remove(identity)
T = [identity] + T
return T
def _coset_representative(self, g, H):
"""Return the representative of Hg from the transversal that
would be computed by ``self.coset_transversal(H)``.
"""
if H.order() == 1:
return g
# The base of self must be an extension of H.base.
if not(self.base[:len(H.base)] == H.base):
self._schreier_sims(base=H.base)
orbits = H.basic_orbits[:]
h_transversals = [list(_.values()) for _ in H.basic_transversals]
transversals = [list(_.values()) for _ in self.basic_transversals]
base = self.base
base_ordering = _base_ordering(base, self.degree)
def step(l, x):
gamma = min(orbits[l], key = lambda y: base_ordering[y^x])
i = [base[l]^h for h in h_transversals[l]].index(gamma)
x = h_transversals[l][i]*x
if l < len(orbits)-1:
for u in transversals[l]:
if base[l]^u == base[l]^x:
break
x = step(l+1, x*u**-1)*u
return x
return step(0, g)
def coset_table(self, H):
"""Return the standardised (right) coset table of self in H as
a list of lists.
"""
# Maybe this should be made to return an instance of CosetTable
# from fp_groups.py but the class would need to be changed first
# to be compatible with PermutationGroups
if not H.is_subgroup(self):
raise ValueError("The argument must be a subgroup")
T = self.coset_transversal(H)
n = len(T)
A = list(chain.from_iterable((gen, gen**-1)
for gen in self.generators))
table = []
for i in range(n):
row = [self._coset_representative(T[i]*x, H) for x in A]
row = [T.index(r) for r in row]
table.append(row)
# standardize (this is the same as the algorithm used in coset_table)
# If CosetTable is made compatible with PermutationGroups, this
# should be replaced by table.standardize()
A = range(len(A))
gamma = 1
for alpha, a in product(range(n), A):
beta = table[alpha][a]
if beta >= gamma:
if beta > gamma:
for x in A:
z = table[gamma][x]
table[gamma][x] = table[beta][x]
table[beta][x] = z
for i in range(n):
if table[i][x] == beta:
table[i][x] = gamma
elif table[i][x] == gamma:
table[i][x] = beta
gamma += 1
if gamma >= n-1:
return table
def center(self):
r"""
Return the center of a permutation group.
Explanation
===========
The center for a group `G` is defined as
`Z(G) = \{z\in G | \forall g\in G, zg = gz \}`,
the set of elements of `G` that commute with all elements of `G`.
It is equal to the centralizer of `G` inside `G`, and is naturally a
subgroup of `G` ([9]).
Examples
========
>>> from sympy.combinatorics.named_groups import DihedralGroup
>>> D = DihedralGroup(4)
>>> G = D.center()
>>> G.order()
2
See Also
========
centralizer
Notes
=====
This is a naive implementation that is a straightforward application
of ``.centralizer()``
"""
if not self._center:
self._center = self.centralizer(self)
return self._center
def centralizer(self, other):
r"""
Return the centralizer of a group/set/element.
Explanation
===========
The centralizer of a set of permutations ``S`` inside
a group ``G`` is the set of elements of ``G`` that commute with all
elements of ``S``::
`C_G(S) = \{ g \in G | gs = sg \forall s \in S\}` ([10])
Usually, ``S`` is a subset of ``G``, but if ``G`` is a proper subgroup of
the full symmetric group, we allow for ``S`` to have elements outside
``G``.
It is naturally a subgroup of ``G``; the centralizer of a permutation
group is equal to the centralizer of any set of generators for that
group, since any element commuting with the generators commutes with
any product of the generators.
Parameters
==========
other
a permutation group/list of permutations/single permutation
Examples
========
>>> from sympy.combinatorics.named_groups import (SymmetricGroup,
... CyclicGroup)
>>> S = SymmetricGroup(6)
>>> C = CyclicGroup(6)
>>> H = S.centralizer(C)
>>> H.is_subgroup(C)
True
See Also
========
subgroup_search
Notes
=====
The implementation is an application of ``.subgroup_search()`` with
tests using a specific base for the group ``G``.
"""
if hasattr(other, 'generators'):
if other.is_trivial or self.is_trivial:
return self
degree = self.degree
identity = _af_new(list(range(degree)))
orbits = other.orbits()
num_orbits = len(orbits)
orbits.sort(key=lambda x: -len(x))
long_base = []
orbit_reps = [None]*num_orbits
orbit_reps_indices = [None]*num_orbits
orbit_descr = [None]*degree
for i in range(num_orbits):
orbit = list(orbits[i])
orbit_reps[i] = orbit[0]
orbit_reps_indices[i] = len(long_base)
for point in orbit:
orbit_descr[point] = i
long_base = long_base + orbit
base, strong_gens = self.schreier_sims_incremental(base=long_base)
strong_gens_distr = _distribute_gens_by_base(base, strong_gens)
i = 0
for i in range(len(base)):
if strong_gens_distr[i] == [identity]:
break
base = base[:i]
base_len = i
for j in range(num_orbits):
if base[base_len - 1] in orbits[j]:
break
rel_orbits = orbits[: j + 1]
num_rel_orbits = len(rel_orbits)
transversals = [None]*num_rel_orbits
for j in range(num_rel_orbits):
rep = orbit_reps[j]
transversals[j] = dict(
other.orbit_transversal(rep, pairs=True))
trivial_test = lambda x: True
tests = [None]*base_len
for l in range(base_len):
if base[l] in orbit_reps:
tests[l] = trivial_test
else:
def test(computed_words, l=l):
g = computed_words[l]
rep_orb_index = orbit_descr[base[l]]
rep = orbit_reps[rep_orb_index]
im = g._array_form[base[l]]
im_rep = g._array_form[rep]
tr_el = transversals[rep_orb_index][base[l]]
# using the definition of transversal,
# base[l]^g = rep^(tr_el*g);
# if g belongs to the centralizer, then
# base[l]^g = (rep^g)^tr_el
return im == tr_el._array_form[im_rep]
tests[l] = test
def prop(g):
return [rmul(g, gen) for gen in other.generators] == \
[rmul(gen, g) for gen in other.generators]
return self.subgroup_search(prop, base=base,
strong_gens=strong_gens, tests=tests)
elif hasattr(other, '__getitem__'):
gens = list(other)
return self.centralizer(PermutationGroup(gens))
elif hasattr(other, 'array_form'):
return self.centralizer(PermutationGroup([other]))
def commutator(self, G, H):
"""
Return the commutator of two subgroups.
Explanation
===========
For a permutation group ``K`` and subgroups ``G``, ``H``, the
commutator of ``G`` and ``H`` is defined as the group generated
by all the commutators `[g, h] = hgh^{-1}g^{-1}` for ``g`` in ``G`` and
``h`` in ``H``. It is naturally a subgroup of ``K`` ([1], p.27).
Examples
========
>>> from sympy.combinatorics.named_groups import (SymmetricGroup,
... AlternatingGroup)
>>> S = SymmetricGroup(5)
>>> A = AlternatingGroup(5)
>>> G = S.commutator(S, A)
>>> G.is_subgroup(A)
True
See Also
========
derived_subgroup
Notes
=====
The commutator of two subgroups `H, G` is equal to the normal closure
of the commutators of all the generators, i.e. `hgh^{-1}g^{-1}` for `h`
a generator of `H` and `g` a generator of `G` ([1], p.28)
"""
ggens = G.generators
hgens = H.generators
commutators = []
for ggen in ggens:
for hgen in hgens:
commutator = rmul(hgen, ggen, ~hgen, ~ggen)
if commutator not in commutators:
commutators.append(commutator)
res = self.normal_closure(commutators)
return res
def coset_factor(self, g, factor_index=False):
"""Return ``G``'s (self's) coset factorization of ``g``
Explanation
===========
If ``g`` is an element of ``G`` then it can be written as the product
of permutations drawn from the Schreier-Sims coset decomposition,
The permutations returned in ``f`` are those for which
the product gives ``g``: ``g = f[n]*...f[1]*f[0]`` where ``n = len(B)``
and ``B = G.base``. f[i] is one of the permutations in
``self._basic_orbits[i]``.
If factor_index==True,
returns a tuple ``[b[0],..,b[n]]``, where ``b[i]``
belongs to ``self._basic_orbits[i]``
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> a = Permutation(0, 1, 3, 7, 6, 4)(2, 5)
>>> b = Permutation(0, 1, 3, 2)(4, 5, 7, 6)
>>> G = PermutationGroup([a, b])
Define g:
>>> g = Permutation(7)(1, 2, 4)(3, 6, 5)
Confirm that it is an element of G:
>>> G.contains(g)
True
Thus, it can be written as a product of factors (up to
3) drawn from u. See below that a factor from u1 and u2
and the Identity permutation have been used:
>>> f = G.coset_factor(g)
>>> f[2]*f[1]*f[0] == g
True
>>> f1 = G.coset_factor(g, True); f1
[0, 4, 4]
>>> tr = G.basic_transversals
>>> f[0] == tr[0][f1[0]]
True
If g is not an element of G then [] is returned:
>>> c = Permutation(5, 6, 7)
>>> G.coset_factor(c)
[]
See Also
========
sympy.combinatorics.util._strip
"""
if isinstance(g, (Cycle, Permutation)):
g = g.list()
if len(g) != self._degree:
# this could either adjust the size or return [] immediately
# but we don't choose between the two and just signal a possible
# error
raise ValueError('g should be the same size as permutations of G')
I = list(range(self._degree))
basic_orbits = self.basic_orbits
transversals = self._transversals
factors = []
base = self.base
h = g
for i in range(len(base)):
beta = h[base[i]]
if beta == base[i]:
factors.append(beta)
continue
if beta not in basic_orbits[i]:
return []
u = transversals[i][beta]._array_form
h = _af_rmul(_af_invert(u), h)
factors.append(beta)
if h != I:
return []
if factor_index:
return factors
tr = self.basic_transversals
factors = [tr[i][factors[i]] for i in range(len(base))]
return factors
def generator_product(self, g, original=False):
r'''
Return a list of strong generators `[s1, \dots, sn]`
s.t `g = sn \times \dots \times s1`. If ``original=True``, make the
list contain only the original group generators
'''
product = []
if g.is_identity:
return []
if g in self.strong_gens:
if not original or g in self.generators:
return [g]
else:
slp = self._strong_gens_slp[g]
for s in slp:
product.extend(self.generator_product(s, original=True))
return product
elif g**-1 in self.strong_gens:
g = g**-1
if not original or g in self.generators:
return [g**-1]
else:
slp = self._strong_gens_slp[g]
for s in slp:
product.extend(self.generator_product(s, original=True))
l = len(product)
product = [product[l-i-1]**-1 for i in range(l)]
return product
f = self.coset_factor(g, True)
for i, j in enumerate(f):
slp = self._transversal_slp[i][j]
for s in slp:
if not original:
product.append(self.strong_gens[s])
else:
s = self.strong_gens[s]
product.extend(self.generator_product(s, original=True))
return product
def coset_rank(self, g):
"""rank using Schreier-Sims representation.
Explanation
===========
The coset rank of ``g`` is the ordering number in which
it appears in the lexicographic listing according to the
coset decomposition
The ordering is the same as in G.generate(method='coset').
If ``g`` does not belong to the group it returns None.
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> a = Permutation(0, 1, 3, 7, 6, 4)(2, 5)
>>> b = Permutation(0, 1, 3, 2)(4, 5, 7, 6)
>>> G = PermutationGroup([a, b])
>>> c = Permutation(7)(2, 4)(3, 5)
>>> G.coset_rank(c)
16
>>> G.coset_unrank(16)
(7)(2 4)(3 5)
See Also
========
coset_factor
"""
factors = self.coset_factor(g, True)
if not factors:
return None
rank = 0
b = 1
transversals = self._transversals
base = self._base
basic_orbits = self._basic_orbits
for i in range(len(base)):
k = factors[i]
j = basic_orbits[i].index(k)
rank += b*j
b = b*len(transversals[i])
return rank
def coset_unrank(self, rank, af=False):
"""unrank using Schreier-Sims representation
coset_unrank is the inverse operation of coset_rank
if 0 <= rank < order; otherwise it returns None.
"""
if rank < 0 or rank >= self.order():
return None
base = self.base
transversals = self.basic_transversals
basic_orbits = self.basic_orbits
m = len(base)
v = [0]*m
for i in range(m):
rank, c = divmod(rank, len(transversals[i]))
v[i] = basic_orbits[i][c]
a = [transversals[i][v[i]]._array_form for i in range(m)]
h = _af_rmuln(*a)
if af:
return h
else:
return _af_new(h)
@property
def degree(self):
"""Returns the size of the permutations in the group.
Explanation
===========
The number of permutations comprising the group is given by
``len(group)``; the number of permutations that can be generated
by the group is given by ``group.order()``.
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> a = Permutation([1, 0, 2])
>>> G = PermutationGroup([a])
>>> G.degree
3
>>> len(G)
1
>>> G.order()
2
>>> list(G.generate())
[(2), (2)(0 1)]
See Also
========
order
"""
return self._degree
@property
def identity(self):
'''
Return the identity element of the permutation group.
'''
return _af_new(list(range(self.degree)))
@property
def elements(self):
"""Returns all the elements of the permutation group as a list
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> p = PermutationGroup(Permutation(1, 3), Permutation(1, 2))
>>> p.elements
[(3), (3)(1 2), (1 3), (2 3), (1 2 3), (1 3 2)]
"""
if not self._elements:
self._elements = list(self.generate())
return self._elements
def derived_series(self):
r"""Return the derived series for the group.
Explanation
===========
The derived series for a group `G` is defined as
`G = G_0 > G_1 > G_2 > \ldots` where `G_i = [G_{i-1}, G_{i-1}]`,
i.e. `G_i` is the derived subgroup of `G_{i-1}`, for
`i\in\mathbb{N}`. When we have `G_k = G_{k-1}` for some
`k\in\mathbb{N}`, the series terminates.
Returns
=======
A list of permutation groups containing the members of the derived
series in the order `G = G_0, G_1, G_2, \ldots`.
Examples
========
>>> from sympy.combinatorics.named_groups import (SymmetricGroup,
... AlternatingGroup, DihedralGroup)
>>> A = AlternatingGroup(5)
>>> len(A.derived_series())
1
>>> S = SymmetricGroup(4)
>>> len(S.derived_series())
4
>>> S.derived_series()[1].is_subgroup(AlternatingGroup(4))
True
>>> S.derived_series()[2].is_subgroup(DihedralGroup(2))
True
See Also
========
derived_subgroup
"""
res = [self]
current = self
nxt = self.derived_subgroup()
while not current.is_subgroup(nxt):
res.append(nxt)
current = nxt
nxt = nxt.derived_subgroup()
return res
def derived_subgroup(self):
r"""Compute the derived subgroup.
Explanation
===========
The derived subgroup, or commutator subgroup is the subgroup generated
by all commutators `[g, h] = hgh^{-1}g^{-1}` for `g, h\in G` ; it is
equal to the normal closure of the set of commutators of the generators
([1], p.28, [11]).
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> a = Permutation([1, 0, 2, 4, 3])
>>> b = Permutation([0, 1, 3, 2, 4])
>>> G = PermutationGroup([a, b])
>>> C = G.derived_subgroup()
>>> list(C.generate(af=True))
[[0, 1, 2, 3, 4], [0, 1, 3, 4, 2], [0, 1, 4, 2, 3]]
See Also
========
derived_series
"""
r = self._r
gens = [p._array_form for p in self.generators]
set_commutators = set()
degree = self._degree
rng = list(range(degree))
for i in range(r):
for j in range(r):
p1 = gens[i]
p2 = gens[j]
c = list(range(degree))
for k in rng:
c[p2[p1[k]]] = p1[p2[k]]
ct = tuple(c)
if ct not in set_commutators:
set_commutators.add(ct)
cms = [_af_new(p) for p in set_commutators]
G2 = self.normal_closure(cms)
return G2
def generate(self, method="coset", af=False):
"""Return iterator to generate the elements of the group.
Explanation
===========
Iteration is done with one of these methods::
method='coset' using the Schreier-Sims coset representation
method='dimino' using the Dimino method
If ``af = True`` it yields the array form of the permutations
Examples
========
>>> from sympy.combinatorics import PermutationGroup
>>> from sympy.combinatorics.polyhedron import tetrahedron
The permutation group given in the tetrahedron object is also
true groups:
>>> G = tetrahedron.pgroup
>>> G.is_group
True
Also the group generated by the permutations in the tetrahedron
pgroup -- even the first two -- is a proper group:
>>> H = PermutationGroup(G[0], G[1])
>>> J = PermutationGroup(list(H.generate())); J
PermutationGroup([
(0 1)(2 3),
(1 2 3),
(1 3 2),
(0 3 1),
(0 2 3),
(0 3)(1 2),
(0 1 3),
(3)(0 2 1),
(0 3 2),
(3)(0 1 2),
(0 2)(1 3)])
>>> _.is_group
True
"""
if method == "coset":
return self.generate_schreier_sims(af)
elif method == "dimino":
return self.generate_dimino(af)
else:
raise NotImplementedError('No generation defined for %s' % method)
def generate_dimino(self, af=False):
"""Yield group elements using Dimino's algorithm.
If ``af == True`` it yields the array form of the permutations.
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> a = Permutation([0, 2, 1, 3])
>>> b = Permutation([0, 2, 3, 1])
>>> g = PermutationGroup([a, b])
>>> list(g.generate_dimino(af=True))
[[0, 1, 2, 3], [0, 2, 1, 3], [0, 2, 3, 1],
[0, 1, 3, 2], [0, 3, 2, 1], [0, 3, 1, 2]]
References
==========
.. [1] The Implementation of Various Algorithms for Permutation Groups in
the Computer Algebra System: AXIOM, N.J. Doye, M.Sc. Thesis
"""
idn = list(range(self.degree))
order = 0
element_list = [idn]
set_element_list = {tuple(idn)}
if af:
yield idn
else:
yield _af_new(idn)
gens = [p._array_form for p in self.generators]
for i in range(len(gens)):
# D elements of the subgroup G_i generated by gens[:i]
D = element_list[:]
N = [idn]
while N:
A = N
N = []
for a in A:
for g in gens[:i + 1]:
ag = _af_rmul(a, g)
if tuple(ag) not in set_element_list:
# produce G_i*g
for d in D:
order += 1
ap = _af_rmul(d, ag)
if af:
yield ap
else:
p = _af_new(ap)
yield p
element_list.append(ap)
set_element_list.add(tuple(ap))
N.append(ap)
self._order = len(element_list)
def generate_schreier_sims(self, af=False):
"""Yield group elements using the Schreier-Sims representation
in coset_rank order
If ``af = True`` it yields the array form of the permutations
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> a = Permutation([0, 2, 1, 3])
>>> b = Permutation([0, 2, 3, 1])
>>> g = PermutationGroup([a, b])
>>> list(g.generate_schreier_sims(af=True))
[[0, 1, 2, 3], [0, 2, 1, 3], [0, 3, 2, 1],
[0, 1, 3, 2], [0, 2, 3, 1], [0, 3, 1, 2]]
"""
n = self._degree
u = self.basic_transversals
basic_orbits = self._basic_orbits
if len(u) == 0:
for x in self.generators:
if af:
yield x._array_form
else:
yield x
return
if len(u) == 1:
for i in basic_orbits[0]:
if af:
yield u[0][i]._array_form
else:
yield u[0][i]
return
u = list(reversed(u))
basic_orbits = basic_orbits[::-1]
# stg stack of group elements
stg = [list(range(n))]
posmax = [len(x) for x in u]
n1 = len(posmax) - 1
pos = [0]*n1
h = 0
while 1:
# backtrack when finished iterating over coset
if pos[h] >= posmax[h]:
if h == 0:
return
pos[h] = 0
h -= 1
stg.pop()
continue
p = _af_rmul(u[h][basic_orbits[h][pos[h]]]._array_form, stg[-1])
pos[h] += 1
stg.append(p)
h += 1
if h == n1:
if af:
for i in basic_orbits[-1]:
p = _af_rmul(u[-1][i]._array_form, stg[-1])
yield p
else:
for i in basic_orbits[-1]:
p = _af_rmul(u[-1][i]._array_form, stg[-1])
p1 = _af_new(p)
yield p1
stg.pop()
h -= 1
@property
def generators(self):
"""Returns the generators of the group.
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> a = Permutation([0, 2, 1])
>>> b = Permutation([1, 0, 2])
>>> G = PermutationGroup([a, b])
>>> G.generators
[(1 2), (2)(0 1)]
"""
return self._generators
def contains(self, g, strict=True):
"""Test if permutation ``g`` belong to self, ``G``.
Explanation
===========
If ``g`` is an element of ``G`` it can be written as a product
of factors drawn from the cosets of ``G``'s stabilizers. To see
if ``g`` is one of the actual generators defining the group use
``G.has(g)``.
If ``strict`` is not ``True``, ``g`` will be resized, if necessary,
to match the size of permutations in ``self``.
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> a = Permutation(1, 2)
>>> b = Permutation(2, 3, 1)
>>> G = PermutationGroup(a, b, degree=5)
>>> G.contains(G[0]) # trivial check
True
>>> elem = Permutation([[2, 3]], size=5)
>>> G.contains(elem)
True
>>> G.contains(Permutation(4)(0, 1, 2, 3))
False
If strict is False, a permutation will be resized, if
necessary:
>>> H = PermutationGroup(Permutation(5))
>>> H.contains(Permutation(3))
False
>>> H.contains(Permutation(3), strict=False)
True
To test if a given permutation is present in the group:
>>> elem in G.generators
False
>>> G.has(elem)
False
See Also
========
coset_factor, sympy.core.basic.Basic.has, __contains__
"""
if not isinstance(g, Permutation):
return False
if g.size != self.degree:
if strict:
return False
g = Permutation(g, size=self.degree)
if g in self.generators:
return True
return bool(self.coset_factor(g.array_form, True))
@property
def is_perfect(self):
"""Return ``True`` if the group is perfect.
A group is perfect if it equals to its derived subgroup.
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> a = Permutation(1,2,3)(4,5)
>>> b = Permutation(1,2,3,4,5)
>>> G = PermutationGroup([a, b])
>>> G.is_perfect
False
"""
if self._is_perfect is None:
self._is_perfect = self.equals(self.derived_subgroup())
return self._is_perfect
@property
def is_abelian(self):
"""Test if the group is Abelian.
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> a = Permutation([0, 2, 1])
>>> b = Permutation([1, 0, 2])
>>> G = PermutationGroup([a, b])
>>> G.is_abelian
False
>>> a = Permutation([0, 2, 1])
>>> G = PermutationGroup([a])
>>> G.is_abelian
True
"""
if self._is_abelian is not None:
return self._is_abelian
self._is_abelian = True
gens = [p._array_form for p in self.generators]
for x in gens:
for y in gens:
if y <= x:
continue
if not _af_commutes_with(x, y):
self._is_abelian = False
return False
return True
def abelian_invariants(self):
"""
Returns the abelian invariants for the given group.
Let ``G`` be a nontrivial finite abelian group. Then G is isomorphic to
the direct product of finitely many nontrivial cyclic groups of
prime-power order.
Explanation
===========
The prime-powers that occur as the orders of the factors are uniquely
determined by G. More precisely, the primes that occur in the orders of the
factors in any such decomposition of ``G`` are exactly the primes that divide
``|G|`` and for any such prime ``p``, if the orders of the factors that are
p-groups in one such decomposition of ``G`` are ``p^{t_1} >= p^{t_2} >= ... p^{t_r}``,
then the orders of the factors that are p-groups in any such decomposition of ``G``
are ``p^{t_1} >= p^{t_2} >= ... p^{t_r}``.
The uniquely determined integers ``p^{t_1} >= p^{t_2} >= ... p^{t_r}``, taken
for all primes that divide ``|G|`` are called the invariants of the nontrivial
group ``G`` as suggested in ([14], p. 542).
Notes
=====
We adopt the convention that the invariants of a trivial group are [].
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> a = Permutation([0, 2, 1])
>>> b = Permutation([1, 0, 2])
>>> G = PermutationGroup([a, b])
>>> G.abelian_invariants()
[2]
>>> from sympy.combinatorics import CyclicGroup
>>> G = CyclicGroup(7)
>>> G.abelian_invariants()
[7]
"""
if self.is_trivial:
return []
gns = self.generators
inv = []
G = self
H = G.derived_subgroup()
Hgens = H.generators
for p in primefactors(G.order()):
ranks = []
while True:
pows = []
for g in gns:
elm = g**p
if not H.contains(elm):
pows.append(elm)
K = PermutationGroup(Hgens + pows) if pows else H
r = G.order()//K.order()
G = K
gns = pows
if r == 1:
break
ranks.append(multiplicity(p, r))
if ranks:
pows = [1]*ranks[0]
for i in ranks:
for j in range(i):
pows[j] = pows[j]*p
inv.extend(pows)
inv.sort()
return inv
def is_elementary(self, p):
"""Return ``True`` if the group is elementary abelian. An elementary
abelian group is a finite abelian group, where every nontrivial
element has order `p`, where `p` is a prime.
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> a = Permutation([0, 2, 1])
>>> G = PermutationGroup([a])
>>> G.is_elementary(2)
True
>>> a = Permutation([0, 2, 1, 3])
>>> b = Permutation([3, 1, 2, 0])
>>> G = PermutationGroup([a, b])
>>> G.is_elementary(2)
True
>>> G.is_elementary(3)
False
"""
return self.is_abelian and all(g.order() == p for g in self.generators)
def _eval_is_alt_sym_naive(self, only_sym=False, only_alt=False):
"""A naive test using the group order."""
if only_sym and only_alt:
raise ValueError(
"Both {} and {} cannot be set to True"
.format(only_sym, only_alt))
n = self.degree
sym_order = _factorial(n)
order = self.order()
if order == sym_order:
self._is_sym = True
self._is_alt = False
if only_alt:
return False
return True
elif 2*order == sym_order:
self._is_sym = False
self._is_alt = True
if only_sym:
return False
return True
return False
def _eval_is_alt_sym_monte_carlo(self, eps=0.05, perms=None):
"""A test using monte-carlo algorithm.
Parameters
==========
eps : float, optional
The criterion for the incorrect ``False`` return.
perms : list[Permutation], optional
If explicitly given, it tests over the given candidates
for testing.
If ``None``, it randomly computes ``N_eps`` and chooses
``N_eps`` sample of the permutation from the group.
See Also
========
_check_cycles_alt_sym
"""
if perms is None:
n = self.degree
if n < 17:
c_n = 0.34
else:
c_n = 0.57
d_n = (c_n*log(2))/log(n)
N_eps = int(-log(eps)/d_n)
perms = (self.random_pr() for i in range(N_eps))
return self._eval_is_alt_sym_monte_carlo(perms=perms)
for perm in perms:
if _check_cycles_alt_sym(perm):
return True
return False
def is_alt_sym(self, eps=0.05, _random_prec=None):
r"""Monte Carlo test for the symmetric/alternating group for degrees
>= 8.
Explanation
===========
More specifically, it is one-sided Monte Carlo with the
answer True (i.e., G is symmetric/alternating) guaranteed to be
correct, and the answer False being incorrect with probability eps.
For degree < 8, the order of the group is checked so the test
is deterministic.
Notes
=====
The algorithm itself uses some nontrivial results from group theory and
number theory:
1) If a transitive group ``G`` of degree ``n`` contains an element
with a cycle of length ``n/2 < p < n-2`` for ``p`` a prime, ``G`` is the
symmetric or alternating group ([1], pp. 81-82)
2) The proportion of elements in the symmetric/alternating group having
the property described in 1) is approximately `\log(2)/\log(n)`
([1], p.82; [2], pp. 226-227).
The helper function ``_check_cycles_alt_sym`` is used to
go over the cycles in a permutation and look for ones satisfying 1).
Examples
========
>>> from sympy.combinatorics.named_groups import DihedralGroup
>>> D = DihedralGroup(10)
>>> D.is_alt_sym()
False
See Also
========
_check_cycles_alt_sym
"""
if _random_prec is not None:
N_eps = _random_prec['N_eps']
perms= (_random_prec[i] for i in range(N_eps))
return self._eval_is_alt_sym_monte_carlo(perms=perms)
if self._is_sym or self._is_alt:
return True
if self._is_sym is False and self._is_alt is False:
return False
n = self.degree
if n < 8:
return self._eval_is_alt_sym_naive()
elif self.is_transitive():
return self._eval_is_alt_sym_monte_carlo(eps=eps)
self._is_sym, self._is_alt = False, False
return False
@property
def is_nilpotent(self):
"""Test if the group is nilpotent.
Explanation
===========
A group `G` is nilpotent if it has a central series of finite length.
Alternatively, `G` is nilpotent if its lower central series terminates
with the trivial group. Every nilpotent group is also solvable
([1], p.29, [12]).
Examples
========
>>> from sympy.combinatorics.named_groups import (SymmetricGroup,
... CyclicGroup)
>>> C = CyclicGroup(6)
>>> C.is_nilpotent
True
>>> S = SymmetricGroup(5)
>>> S.is_nilpotent
False
See Also
========
lower_central_series, is_solvable
"""
if self._is_nilpotent is None:
lcs = self.lower_central_series()
terminator = lcs[len(lcs) - 1]
gens = terminator.generators
degree = self.degree
identity = _af_new(list(range(degree)))
if all(g == identity for g in gens):
self._is_solvable = True
self._is_nilpotent = True
return True
else:
self._is_nilpotent = False
return False
else:
return self._is_nilpotent
def is_normal(self, gr, strict=True):
"""Test if ``G=self`` is a normal subgroup of ``gr``.
Explanation
===========
G is normal in gr if
for each g2 in G, g1 in gr, ``g = g1*g2*g1**-1`` belongs to G
It is sufficient to check this for each g1 in gr.generators and
g2 in G.generators.
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> a = Permutation([1, 2, 0])
>>> b = Permutation([1, 0, 2])
>>> G = PermutationGroup([a, b])
>>> G1 = PermutationGroup([a, Permutation([2, 0, 1])])
>>> G1.is_normal(G)
True
"""
if not self.is_subgroup(gr, strict=strict):
return False
d_self = self.degree
d_gr = gr.degree
if self.is_trivial and (d_self == d_gr or not strict):
return True
if self._is_abelian:
return True
new_self = self.copy()
if not strict and d_self != d_gr:
if d_self < d_gr:
new_self = PermGroup(new_self.generators + [Permutation(d_gr - 1)])
else:
gr = PermGroup(gr.generators + [Permutation(d_self - 1)])
gens2 = [p._array_form for p in new_self.generators]
gens1 = [p._array_form for p in gr.generators]
for g1 in gens1:
for g2 in gens2:
p = _af_rmuln(g1, g2, _af_invert(g1))
if not new_self.coset_factor(p, True):
return False
return True
def is_primitive(self, randomized=True):
r"""Test if a group is primitive.
Explanation
===========
A permutation group ``G`` acting on a set ``S`` is called primitive if
``S`` contains no nontrivial block under the action of ``G``
(a block is nontrivial if its cardinality is more than ``1``).
Notes
=====
The algorithm is described in [1], p.83, and uses the function
minimal_block to search for blocks of the form `\{0, k\}` for ``k``
ranging over representatives for the orbits of `G_0`, the stabilizer of
``0``. This algorithm has complexity `O(n^2)` where ``n`` is the degree
of the group, and will perform badly if `G_0` is small.
There are two implementations offered: one finds `G_0`
deterministically using the function ``stabilizer``, and the other
(default) produces random elements of `G_0` using ``random_stab``,
hoping that they generate a subgroup of `G_0` with not too many more
orbits than `G_0` (this is suggested in [1], p.83). Behavior is changed
by the ``randomized`` flag.
Examples
========
>>> from sympy.combinatorics.named_groups import DihedralGroup
>>> D = DihedralGroup(10)
>>> D.is_primitive()
False
See Also
========
minimal_block, random_stab
"""
if self._is_primitive is not None:
return self._is_primitive
if self.is_transitive() is False:
return False
if randomized:
random_stab_gens = []
v = self.schreier_vector(0)
for _ in range(len(self)):
random_stab_gens.append(self.random_stab(0, v))
stab = PermutationGroup(random_stab_gens)
else:
stab = self.stabilizer(0)
orbits = stab.orbits()
for orb in orbits:
x = orb.pop()
if x != 0 and any(e != 0 for e in self.minimal_block([0, x])):
self._is_primitive = False
return False
self._is_primitive = True
return True
def minimal_blocks(self, randomized=True):
'''
For a transitive group, return the list of all minimal
block systems. If a group is intransitive, return `False`.
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> from sympy.combinatorics.named_groups import DihedralGroup
>>> DihedralGroup(6).minimal_blocks()
[[0, 1, 0, 1, 0, 1], [0, 1, 2, 0, 1, 2]]
>>> G = PermutationGroup(Permutation(1,2,5))
>>> G.minimal_blocks()
False
See Also
========
minimal_block, is_transitive, is_primitive
'''
def _number_blocks(blocks):
# number the blocks of a block system
# in order and return the number of
# blocks and the tuple with the
# reordering
n = len(blocks)
appeared = {}
m = 0
b = [None]*n
for i in range(n):
if blocks[i] not in appeared:
appeared[blocks[i]] = m
b[i] = m
m += 1
else:
b[i] = appeared[blocks[i]]
return tuple(b), m
if not self.is_transitive():
return False
blocks = []
num_blocks = []
rep_blocks = []
if randomized:
random_stab_gens = []
v = self.schreier_vector(0)
for i in range(len(self)):
random_stab_gens.append(self.random_stab(0, v))
stab = PermutationGroup(random_stab_gens)
else:
stab = self.stabilizer(0)
orbits = stab.orbits()
for orb in orbits:
x = orb.pop()
if x != 0:
block = self.minimal_block([0, x])
num_block, _ = _number_blocks(block)
# a representative block (containing 0)
rep = {j for j in range(self.degree) if num_block[j] == 0}
# check if the system is minimal with
# respect to the already discovere ones
minimal = True
blocks_remove_mask = [False] * len(blocks)
for i, r in enumerate(rep_blocks):
if len(r) > len(rep) and rep.issubset(r):
# i-th block system is not minimal
blocks_remove_mask[i] = True
elif len(r) < len(rep) and r.issubset(rep):
# the system being checked is not minimal
minimal = False
break
# remove non-minimal representative blocks
blocks = [b for i, b in enumerate(blocks) if not blocks_remove_mask[i]]
num_blocks = [n for i, n in enumerate(num_blocks) if not blocks_remove_mask[i]]
rep_blocks = [r for i, r in enumerate(rep_blocks) if not blocks_remove_mask[i]]
if minimal and num_block not in num_blocks:
blocks.append(block)
num_blocks.append(num_block)
rep_blocks.append(rep)
return blocks
@property
def is_solvable(self):
"""Test if the group is solvable.
``G`` is solvable if its derived series terminates with the trivial
group ([1], p.29).
Examples
========
>>> from sympy.combinatorics.named_groups import SymmetricGroup
>>> S = SymmetricGroup(3)
>>> S.is_solvable
True
See Also
========
is_nilpotent, derived_series
"""
if self._is_solvable is None:
if self.order() % 2 != 0:
return True
ds = self.derived_series()
terminator = ds[len(ds) - 1]
gens = terminator.generators
degree = self.degree
identity = _af_new(list(range(degree)))
if all(g == identity for g in gens):
self._is_solvable = True
return True
else:
self._is_solvable = False
return False
else:
return self._is_solvable
def is_subgroup(self, G, strict=True):
"""Return ``True`` if all elements of ``self`` belong to ``G``.
If ``strict`` is ``False`` then if ``self``'s degree is smaller
than ``G``'s, the elements will be resized to have the same degree.
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> from sympy.combinatorics import SymmetricGroup, CyclicGroup
Testing is strict by default: the degree of each group must be the
same:
>>> p = Permutation(0, 1, 2, 3, 4, 5)
>>> G1 = PermutationGroup([Permutation(0, 1, 2), Permutation(0, 1)])
>>> G2 = PermutationGroup([Permutation(0, 2), Permutation(0, 1, 2)])
>>> G3 = PermutationGroup([p, p**2])
>>> assert G1.order() == G2.order() == G3.order() == 6
>>> G1.is_subgroup(G2)
True
>>> G1.is_subgroup(G3)
False
>>> G3.is_subgroup(PermutationGroup(G3[1]))
False
>>> G3.is_subgroup(PermutationGroup(G3[0]))
True
To ignore the size, set ``strict`` to ``False``:
>>> S3 = SymmetricGroup(3)
>>> S5 = SymmetricGroup(5)
>>> S3.is_subgroup(S5, strict=False)
True
>>> C7 = CyclicGroup(7)
>>> G = S5*C7
>>> S5.is_subgroup(G, False)
True
>>> C7.is_subgroup(G, 0)
False
"""
if isinstance(G, SymmetricPermutationGroup):
if self.degree != G.degree:
return False
return True
if not isinstance(G, PermutationGroup):
return False
if self == G or self.generators[0]==Permutation():
return True
if G.order() % self.order() != 0:
return False
if self.degree == G.degree or \
(self.degree < G.degree and not strict):
gens = self.generators
else:
return False
return all(G.contains(g, strict=strict) for g in gens)
@property
def is_polycyclic(self):
"""Return ``True`` if a group is polycyclic. A group is polycyclic if
it has a subnormal series with cyclic factors. For finite groups,
this is the same as if the group is solvable.
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> a = Permutation([0, 2, 1, 3])
>>> b = Permutation([2, 0, 1, 3])
>>> G = PermutationGroup([a, b])
>>> G.is_polycyclic
True
"""
return self.is_solvable
def is_transitive(self, strict=True):
"""Test if the group is transitive.
Explanation
===========
A group is transitive if it has a single orbit.
If ``strict`` is ``False`` the group is transitive if it has
a single orbit of length different from 1.
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> a = Permutation([0, 2, 1, 3])
>>> b = Permutation([2, 0, 1, 3])
>>> G1 = PermutationGroup([a, b])
>>> G1.is_transitive()
False
>>> G1.is_transitive(strict=False)
True
>>> c = Permutation([2, 3, 0, 1])
>>> G2 = PermutationGroup([a, c])
>>> G2.is_transitive()
True
>>> d = Permutation([1, 0, 2, 3])
>>> e = Permutation([0, 1, 3, 2])
>>> G3 = PermutationGroup([d, e])
>>> G3.is_transitive() or G3.is_transitive(strict=False)
False
"""
if self._is_transitive: # strict or not, if True then True
return self._is_transitive
if strict:
if self._is_transitive is not None: # we only store strict=True
return self._is_transitive
ans = len(self.orbit(0)) == self.degree
self._is_transitive = ans
return ans
got_orb = False
for x in self.orbits():
if len(x) > 1:
if got_orb:
return False
got_orb = True
return got_orb
@property
def is_trivial(self):
"""Test if the group is the trivial group.
This is true if the group contains only the identity permutation.
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> G = PermutationGroup([Permutation([0, 1, 2])])
>>> G.is_trivial
True
"""
if self._is_trivial is None:
self._is_trivial = len(self) == 1 and self[0].is_Identity
return self._is_trivial
def lower_central_series(self):
r"""Return the lower central series for the group.
The lower central series for a group `G` is the series
`G = G_0 > G_1 > G_2 > \ldots` where
`G_k = [G, G_{k-1}]`, i.e. every term after the first is equal to the
commutator of `G` and the previous term in `G1` ([1], p.29).
Returns
=======
A list of permutation groups in the order `G = G_0, G_1, G_2, \ldots`
Examples
========
>>> from sympy.combinatorics.named_groups import (AlternatingGroup,
... DihedralGroup)
>>> A = AlternatingGroup(4)
>>> len(A.lower_central_series())
2
>>> A.lower_central_series()[1].is_subgroup(DihedralGroup(2))
True
See Also
========
commutator, derived_series
"""
res = [self]
current = self
nxt = self.commutator(self, current)
while not current.is_subgroup(nxt):
res.append(nxt)
current = nxt
nxt = self.commutator(self, current)
return res
@property
def max_div(self):
"""Maximum proper divisor of the degree of a permutation group.
Explanation
===========
Obviously, this is the degree divided by its minimal proper divisor
(larger than ``1``, if one exists). As it is guaranteed to be prime,
the ``sieve`` from ``sympy.ntheory`` is used.
This function is also used as an optimization tool for the functions
``minimal_block`` and ``_union_find_merge``.
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> G = PermutationGroup([Permutation([0, 2, 1, 3])])
>>> G.max_div
2
See Also
========
minimal_block, _union_find_merge
"""
if self._max_div is not None:
return self._max_div
n = self.degree
if n == 1:
return 1
for x in sieve:
if n % x == 0:
d = n//x
self._max_div = d
return d
def minimal_block(self, points):
r"""For a transitive group, finds the block system generated by
``points``.
Explanation
===========
If a group ``G`` acts on a set ``S``, a nonempty subset ``B`` of ``S``
is called a block under the action of ``G`` if for all ``g`` in ``G``
we have ``gB = B`` (``g`` fixes ``B``) or ``gB`` and ``B`` have no
common points (``g`` moves ``B`` entirely). ([1], p.23; [6]).
The distinct translates ``gB`` of a block ``B`` for ``g`` in ``G``
partition the set ``S`` and this set of translates is known as a block
system. Moreover, we obviously have that all blocks in the partition
have the same size, hence the block size divides ``|S|`` ([1], p.23).
A ``G``-congruence is an equivalence relation ``~`` on the set ``S``
such that ``a ~ b`` implies ``g(a) ~ g(b)`` for all ``g`` in ``G``.
For a transitive group, the equivalence classes of a ``G``-congruence
and the blocks of a block system are the same thing ([1], p.23).
The algorithm below checks the group for transitivity, and then finds
the ``G``-congruence generated by the pairs ``(p_0, p_1), (p_0, p_2),
..., (p_0,p_{k-1})`` which is the same as finding the maximal block
system (i.e., the one with minimum block size) such that
``p_0, ..., p_{k-1}`` are in the same block ([1], p.83).
It is an implementation of Atkinson's algorithm, as suggested in [1],
and manipulates an equivalence relation on the set ``S`` using a
union-find data structure. The running time is just above
`O(|points||S|)`. ([1], pp. 83-87; [7]).
Examples
========
>>> from sympy.combinatorics.named_groups import DihedralGroup
>>> D = DihedralGroup(10)
>>> D.minimal_block([0, 5])
[0, 1, 2, 3, 4, 0, 1, 2, 3, 4]
>>> D.minimal_block([0, 1])
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
See Also
========
_union_find_rep, _union_find_merge, is_transitive, is_primitive
"""
if not self.is_transitive():
return False
n = self.degree
gens = self.generators
# initialize the list of equivalence class representatives
parents = list(range(n))
ranks = [1]*n
not_rep = []
k = len(points)
# the block size must divide the degree of the group
if k > self.max_div:
return [0]*n
for i in range(k - 1):
parents[points[i + 1]] = points[0]
not_rep.append(points[i + 1])
ranks[points[0]] = k
i = 0
len_not_rep = k - 1
while i < len_not_rep:
gamma = not_rep[i]
i += 1
for gen in gens:
# find has side effects: performs path compression on the list
# of representatives
delta = self._union_find_rep(gamma, parents)
# union has side effects: performs union by rank on the list
# of representatives
temp = self._union_find_merge(gen(gamma), gen(delta), ranks,
parents, not_rep)
if temp == -1:
return [0]*n
len_not_rep += temp
for i in range(n):
# force path compression to get the final state of the equivalence
# relation
self._union_find_rep(i, parents)
# rewrite result so that block representatives are minimal
new_reps = {}
return [new_reps.setdefault(r, i) for i, r in enumerate(parents)]
def conjugacy_class(self, x):
r"""Return the conjugacy class of an element in the group.
Explanation
===========
The conjugacy class of an element ``g`` in a group ``G`` is the set of
elements ``x`` in ``G`` that are conjugate with ``g``, i.e. for which
``g = xax^{-1}``
for some ``a`` in ``G``.
Note that conjugacy is an equivalence relation, and therefore that
conjugacy classes are partitions of ``G``. For a list of all the
conjugacy classes of the group, use the conjugacy_classes() method.
In a permutation group, each conjugacy class corresponds to a particular
`cycle structure': for example, in ``S_3``, the conjugacy classes are:
* the identity class, ``{()}``
* all transpositions, ``{(1 2), (1 3), (2 3)}``
* all 3-cycles, ``{(1 2 3), (1 3 2)}``
Examples
========
>>> from sympy.combinatorics import Permutation, SymmetricGroup
>>> S3 = SymmetricGroup(3)
>>> S3.conjugacy_class(Permutation(0, 1, 2))
{(0 1 2), (0 2 1)}
Notes
=====
This procedure computes the conjugacy class directly by finding the
orbit of the element under conjugation in G. This algorithm is only
feasible for permutation groups of relatively small order, but is like
the orbit() function itself in that respect.
"""
# Ref: "Computing the conjugacy classes of finite groups"; Butler, G.
# Groups '93 Galway/St Andrews; edited by Campbell, C. M.
new_class = {x}
last_iteration = new_class
while len(last_iteration) > 0:
this_iteration = set()
for y in last_iteration:
for s in self.generators:
conjugated = s * y * (~s)
if conjugated not in new_class:
this_iteration.add(conjugated)
new_class.update(last_iteration)
last_iteration = this_iteration
return new_class
def conjugacy_classes(self):
r"""Return the conjugacy classes of the group.
Explanation
===========
As described in the documentation for the .conjugacy_class() function,
conjugacy is an equivalence relation on a group G which partitions the
set of elements. This method returns a list of all these conjugacy
classes of G.
Examples
========
>>> from sympy.combinatorics import SymmetricGroup
>>> SymmetricGroup(3).conjugacy_classes()
[{(2)}, {(0 1 2), (0 2 1)}, {(0 2), (1 2), (2)(0 1)}]
"""
identity = _af_new(list(range(self.degree)))
known_elements = {identity}
classes = [known_elements.copy()]
for x in self.generate():
if x not in known_elements:
new_class = self.conjugacy_class(x)
classes.append(new_class)
known_elements.update(new_class)
return classes
def normal_closure(self, other, k=10):
r"""Return the normal closure of a subgroup/set of permutations.
Explanation
===========
If ``S`` is a subset of a group ``G``, the normal closure of ``A`` in ``G``
is defined as the intersection of all normal subgroups of ``G`` that
contain ``A`` ([1], p.14). Alternatively, it is the group generated by
the conjugates ``x^{-1}yx`` for ``x`` a generator of ``G`` and ``y`` a
generator of the subgroup ``\left\langle S\right\rangle`` generated by
``S`` (for some chosen generating set for ``\left\langle S\right\rangle``)
([1], p.73).
Parameters
==========
other
a subgroup/list of permutations/single permutation
k
an implementation-specific parameter that determines the number
of conjugates that are adjoined to ``other`` at once
Examples
========
>>> from sympy.combinatorics.named_groups import (SymmetricGroup,
... CyclicGroup, AlternatingGroup)
>>> S = SymmetricGroup(5)
>>> C = CyclicGroup(5)
>>> G = S.normal_closure(C)
>>> G.order()
60
>>> G.is_subgroup(AlternatingGroup(5))
True
See Also
========
commutator, derived_subgroup, random_pr
Notes
=====
The algorithm is described in [1], pp. 73-74; it makes use of the
generation of random elements for permutation groups by the product
replacement algorithm.
"""
if hasattr(other, 'generators'):
degree = self.degree
identity = _af_new(list(range(degree)))
if all(g == identity for g in other.generators):
return other
Z = PermutationGroup(other.generators[:])
base, strong_gens = Z.schreier_sims_incremental()
strong_gens_distr = _distribute_gens_by_base(base, strong_gens)
basic_orbits, basic_transversals = \
_orbits_transversals_from_bsgs(base, strong_gens_distr)
self._random_pr_init(r=10, n=20)
_loop = True
while _loop:
Z._random_pr_init(r=10, n=10)
for _ in range(k):
g = self.random_pr()
h = Z.random_pr()
conj = h^g
res = _strip(conj, base, basic_orbits, basic_transversals)
if res[0] != identity or res[1] != len(base) + 1:
gens = Z.generators
gens.append(conj)
Z = PermutationGroup(gens)
strong_gens.append(conj)
temp_base, temp_strong_gens = \
Z.schreier_sims_incremental(base, strong_gens)
base, strong_gens = temp_base, temp_strong_gens
strong_gens_distr = \
_distribute_gens_by_base(base, strong_gens)
basic_orbits, basic_transversals = \
_orbits_transversals_from_bsgs(base,
strong_gens_distr)
_loop = False
for g in self.generators:
for h in Z.generators:
conj = h^g
res = _strip(conj, base, basic_orbits,
basic_transversals)
if res[0] != identity or res[1] != len(base) + 1:
_loop = True
break
if _loop:
break
return Z
elif hasattr(other, '__getitem__'):
return self.normal_closure(PermutationGroup(other))
elif hasattr(other, 'array_form'):
return self.normal_closure(PermutationGroup([other]))
def orbit(self, alpha, action='tuples'):
r"""Compute the orbit of alpha `\{g(\alpha) | g \in G\}` as a set.
Explanation
===========
The time complexity of the algorithm used here is `O(|Orb|*r)` where
`|Orb|` is the size of the orbit and ``r`` is the number of generators of
the group. For a more detailed analysis, see [1], p.78, [2], pp. 19-21.
Here alpha can be a single point, or a list of points.
If alpha is a single point, the ordinary orbit is computed.
if alpha is a list of points, there are three available options:
'union' - computes the union of the orbits of the points in the list
'tuples' - computes the orbit of the list interpreted as an ordered
tuple under the group action ( i.e., g((1,2,3)) = (g(1), g(2), g(3)) )
'sets' - computes the orbit of the list interpreted as a sets
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> a = Permutation([1, 2, 0, 4, 5, 6, 3])
>>> G = PermutationGroup([a])
>>> G.orbit(0)
{0, 1, 2}
>>> G.orbit([0, 4], 'union')
{0, 1, 2, 3, 4, 5, 6}
See Also
========
orbit_transversal
"""
return _orbit(self.degree, self.generators, alpha, action)
def orbit_rep(self, alpha, beta, schreier_vector=None):
"""Return a group element which sends ``alpha`` to ``beta``.
Explanation
===========
If ``beta`` is not in the orbit of ``alpha``, the function returns
``False``. This implementation makes use of the schreier vector.
For a proof of correctness, see [1], p.80
Examples
========
>>> from sympy.combinatorics.named_groups import AlternatingGroup
>>> G = AlternatingGroup(5)
>>> G.orbit_rep(0, 4)
(0 4 1 2 3)
See Also
========
schreier_vector
"""
if schreier_vector is None:
schreier_vector = self.schreier_vector(alpha)
if schreier_vector[beta] is None:
return False
k = schreier_vector[beta]
gens = [x._array_form for x in self.generators]
a = []
while k != -1:
a.append(gens[k])
beta = gens[k].index(beta) # beta = (~gens[k])(beta)
k = schreier_vector[beta]
if a:
return _af_new(_af_rmuln(*a))
else:
return _af_new(list(range(self._degree)))
def orbit_transversal(self, alpha, pairs=False):
r"""Computes a transversal for the orbit of ``alpha`` as a set.
Explanation
===========
For a permutation group `G`, a transversal for the orbit
`Orb = \{g(\alpha) | g \in G\}` is a set
`\{g_\beta | g_\beta(\alpha) = \beta\}` for `\beta \in Orb`.
Note that there may be more than one possible transversal.
If ``pairs`` is set to ``True``, it returns the list of pairs
`(\beta, g_\beta)`. For a proof of correctness, see [1], p.79
Examples
========
>>> from sympy.combinatorics.named_groups import DihedralGroup
>>> G = DihedralGroup(6)
>>> G.orbit_transversal(0)
[(5), (0 1 2 3 4 5), (0 5)(1 4)(2 3), (0 2 4)(1 3 5), (5)(0 4)(1 3), (0 3)(1 4)(2 5)]
See Also
========
orbit
"""
return _orbit_transversal(self._degree, self.generators, alpha, pairs)
def orbits(self, rep=False):
"""Return the orbits of ``self``, ordered according to lowest element
in each orbit.
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> a = Permutation(1, 5)(2, 3)(4, 0, 6)
>>> b = Permutation(1, 5)(3, 4)(2, 6, 0)
>>> G = PermutationGroup([a, b])
>>> G.orbits()
[{0, 2, 3, 4, 6}, {1, 5}]
"""
return _orbits(self._degree, self._generators)
def order(self):
"""Return the order of the group: the number of permutations that
can be generated from elements of the group.
The number of permutations comprising the group is given by
``len(group)``; the length of each permutation in the group is
given by ``group.size``.
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> a = Permutation([1, 0, 2])
>>> G = PermutationGroup([a])
>>> G.degree
3
>>> len(G)
1
>>> G.order()
2
>>> list(G.generate())
[(2), (2)(0 1)]
>>> a = Permutation([0, 2, 1])
>>> b = Permutation([1, 0, 2])
>>> G = PermutationGroup([a, b])
>>> G.order()
6
See Also
========
degree
"""
if self._order is not None:
return self._order
if self._is_sym:
n = self._degree
self._order = factorial(n)
return self._order
if self._is_alt:
n = self._degree
self._order = factorial(n)/2
return self._order
m = prod([len(x) for x in self.basic_transversals])
self._order = m
return m
def index(self, H):
"""
Returns the index of a permutation group.
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> a = Permutation(1,2,3)
>>> b =Permutation(3)
>>> G = PermutationGroup([a])
>>> H = PermutationGroup([b])
>>> G.index(H)
3
"""
if H.is_subgroup(self):
return self.order()//H.order()
@property
def is_symmetric(self):
"""Return ``True`` if the group is symmetric.
Examples
========
>>> from sympy.combinatorics import SymmetricGroup
>>> g = SymmetricGroup(5)
>>> g.is_symmetric
True
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> g = PermutationGroup(
... Permutation(0, 1, 2, 3, 4),
... Permutation(2, 3))
>>> g.is_symmetric
True
Notes
=====
This uses a naive test involving the computation of the full
group order.
If you need more quicker taxonomy for large groups, you can use
:meth:`PermutationGroup.is_alt_sym`.
However, :meth:`PermutationGroup.is_alt_sym` may not be accurate
and is not able to distinguish between an alternating group and
a symmetric group.
See Also
========
is_alt_sym
"""
_is_sym = self._is_sym
if _is_sym is not None:
return _is_sym
n = self.degree
if n >= 8:
if self.is_transitive():
_is_alt_sym = self._eval_is_alt_sym_monte_carlo()
if _is_alt_sym:
if any(g.is_odd for g in self.generators):
self._is_sym, self._is_alt = True, False
return True
self._is_sym, self._is_alt = False, True
return False
return self._eval_is_alt_sym_naive(only_sym=True)
self._is_sym, self._is_alt = False, False
return False
return self._eval_is_alt_sym_naive(only_sym=True)
@property
def is_alternating(self):
"""Return ``True`` if the group is alternating.
Examples
========
>>> from sympy.combinatorics import AlternatingGroup
>>> g = AlternatingGroup(5)
>>> g.is_alternating
True
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> g = PermutationGroup(
... Permutation(0, 1, 2, 3, 4),
... Permutation(2, 3, 4))
>>> g.is_alternating
True
Notes
=====
This uses a naive test involving the computation of the full
group order.
If you need more quicker taxonomy for large groups, you can use
:meth:`PermutationGroup.is_alt_sym`.
However, :meth:`PermutationGroup.is_alt_sym` may not be accurate
and is not able to distinguish between an alternating group and
a symmetric group.
See Also
========
is_alt_sym
"""
_is_alt = self._is_alt
if _is_alt is not None:
return _is_alt
n = self.degree
if n >= 8:
if self.is_transitive():
_is_alt_sym = self._eval_is_alt_sym_monte_carlo()
if _is_alt_sym:
if all(g.is_even for g in self.generators):
self._is_sym, self._is_alt = False, True
return True
self._is_sym, self._is_alt = True, False
return False
return self._eval_is_alt_sym_naive(only_alt=True)
self._is_sym, self._is_alt = False, False
return False
return self._eval_is_alt_sym_naive(only_alt=True)
@classmethod
def _distinct_primes_lemma(cls, primes):
"""Subroutine to test if there is only one cyclic group for the
order."""
primes = sorted(primes)
l = len(primes)
for i in range(l):
for j in range(i+1, l):
if primes[j] % primes[i] == 1:
return None
return True
@property
def is_cyclic(self):
r"""
Return ``True`` if the group is Cyclic.
Examples
========
>>> from sympy.combinatorics.named_groups import AbelianGroup
>>> G = AbelianGroup(3, 4)
>>> G.is_cyclic
True
>>> G = AbelianGroup(4, 4)
>>> G.is_cyclic
False
Notes
=====
If the order of a group $n$ can be factored into the distinct
primes $p_1, p_2, \dots , p_s$ and if
.. math::
\forall i, j \in \{1, 2, \dots, s \}:
p_i \not \equiv 1 \pmod {p_j}
holds true, there is only one group of the order $n$ which
is a cyclic group [1]_. This is a generalization of the lemma
that the group of order $15, 35, \dots$ are cyclic.
And also, these additional lemmas can be used to test if a
group is cyclic if the order of the group is already found.
- If the group is abelian and the order of the group is
square-free, the group is cyclic.
- If the order of the group is less than $6$ and is not $4$, the
group is cyclic.
- If the order of the group is prime, the group is cyclic.
References
==========
.. [1] 1978: John S. Rose: A Course on Group Theory,
Introduction to Finite Group Theory: 1.4
"""
if self._is_cyclic is not None:
return self._is_cyclic
if len(self.generators) == 1:
self._is_cyclic = True
self._is_abelian = True
return True
if self._is_abelian is False:
self._is_cyclic = False
return False
order = self.order()
if order < 6:
self._is_abelian = True
if order != 4:
self._is_cyclic = True
return True
factors = factorint(order)
if all(v == 1 for v in factors.values()):
if self._is_abelian:
self._is_cyclic = True
return True
primes = list(factors.keys())
if PermutationGroup._distinct_primes_lemma(primes) is True:
self._is_cyclic = True
self._is_abelian = True
return True
if not self.is_abelian:
self._is_cyclic = False
return False
self._is_cyclic = all(
any(g**(order//p) != self.identity for g in self.generators)
for p, e in factors.items() if e > 1
)
return self._is_cyclic
@property
def is_dihedral(self):
r"""
Return ``True`` if the group is dihedral.
Examples
========
>>> from sympy.combinatorics.perm_groups import PermutationGroup
>>> from sympy.combinatorics.permutations import Permutation
>>> from sympy.combinatorics.named_groups import SymmetricGroup, CyclicGroup
>>> G = PermutationGroup(Permutation(1, 6)(2, 5)(3, 4), Permutation(0, 1, 2, 3, 4, 5, 6))
>>> G.is_dihedral
True
>>> G = SymmetricGroup(3)
>>> G.is_dihedral
True
>>> G = CyclicGroup(6)
>>> G.is_dihedral
False
References
==========
.. [Di1] https://math.stackexchange.com/questions/827230/given-a-cayley-table-is-there-an-algorithm-to-determine-if-it-is-a-dihedral-gro/827273#827273
.. [Di2] https://kconrad.math.uconn.edu/blurbs/grouptheory/dihedral.pdf
.. [Di3] https://kconrad.math.uconn.edu/blurbs/grouptheory/dihedral2.pdf
.. [Di4] https://en.wikipedia.org/wiki/Dihedral_group
"""
if self._is_dihedral is not None:
return self._is_dihedral
order = self.order()
if order % 2 == 1:
self._is_dihedral = False
return False
if order == 2:
self._is_dihedral = True
return True
if order == 4:
# The dihedral group of order 4 is the Klein 4-group.
self._is_dihedral = not self.is_cyclic
return self._is_dihedral
if self.is_abelian:
# The only abelian dihedral groups are the ones of orders 2 and 4.
self._is_dihedral = False
return False
# Now we know the group is of even order >= 6, and nonabelian.
n = order // 2
# Handle special cases where there are exactly two generators.
gens = self.generators
if len(gens) == 2:
x, y = gens
a, b = x.order(), y.order()
# Make a >= b
if a < b:
x, y, a, b = y, x, b, a
# Using Theorem 2.1 of [Di3]:
if a == 2 == b:
self._is_dihedral = True
return True
# Using Theorem 1.1 of [Di3]:
if a == n and b == 2 and y*x*y == ~x:
self._is_dihedral = True
return True
# Proceed with algorithm of [Di1]
# Find elements of orders 2 and n
order_2, order_n = [], []
for p in self.elements:
k = p.order()
if k == 2:
order_2.append(p)
elif k == n:
order_n.append(p)
if len(order_2) != n + 1 - (n % 2):
self._is_dihedral = False
return False
if not order_n:
self._is_dihedral = False
return False
x = order_n[0]
# Want an element y of order 2 that is not a power of x
# (i.e. that is not the 180-deg rotation, when n is even).
y = order_2[0]
if n % 2 == 0 and y == x**(n//2):
y = order_2[1]
self._is_dihedral = (y*x*y == ~x)
return self._is_dihedral
def pointwise_stabilizer(self, points, incremental=True):
r"""Return the pointwise stabilizer for a set of points.
Explanation
===========
For a permutation group `G` and a set of points
`\{p_1, p_2,\ldots, p_k\}`, the pointwise stabilizer of
`p_1, p_2, \ldots, p_k` is defined as
`G_{p_1,\ldots, p_k} =
\{g\in G | g(p_i) = p_i \forall i\in\{1, 2,\ldots,k\}\}` ([1],p20).
It is a subgroup of `G`.
Examples
========
>>> from sympy.combinatorics.named_groups import SymmetricGroup
>>> S = SymmetricGroup(7)
>>> Stab = S.pointwise_stabilizer([2, 3, 5])
>>> Stab.is_subgroup(S.stabilizer(2).stabilizer(3).stabilizer(5))
True
See Also
========
stabilizer, schreier_sims_incremental
Notes
=====
When incremental == True,
rather than the obvious implementation using successive calls to
``.stabilizer()``, this uses the incremental Schreier-Sims algorithm
to obtain a base with starting segment - the given points.
"""
if incremental:
base, strong_gens = self.schreier_sims_incremental(base=points)
stab_gens = []
degree = self.degree
for gen in strong_gens:
if [gen(point) for point in points] == points:
stab_gens.append(gen)
if not stab_gens:
stab_gens = _af_new(list(range(degree)))
return PermutationGroup(stab_gens)
else:
gens = self._generators
degree = self.degree
for x in points:
gens = _stabilizer(degree, gens, x)
return PermutationGroup(gens)
def make_perm(self, n, seed=None):
"""
Multiply ``n`` randomly selected permutations from
pgroup together, starting with the identity
permutation. If ``n`` is a list of integers, those
integers will be used to select the permutations and they
will be applied in L to R order: make_perm((A, B, C)) will
give CBA(I) where I is the identity permutation.
``seed`` is used to set the seed for the random selection
of permutations from pgroup. If this is a list of integers,
the corresponding permutations from pgroup will be selected
in the order give. This is mainly used for testing purposes.
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> a, b = [Permutation([1, 0, 3, 2]), Permutation([1, 3, 0, 2])]
>>> G = PermutationGroup([a, b])
>>> G.make_perm(1, [0])
(0 1)(2 3)
>>> G.make_perm(3, [0, 1, 0])
(0 2 3 1)
>>> G.make_perm([0, 1, 0])
(0 2 3 1)
See Also
========
random
"""
if is_sequence(n):
if seed is not None:
raise ValueError('If n is a sequence, seed should be None')
n, seed = len(n), n
else:
try:
n = int(n)
except TypeError:
raise ValueError('n must be an integer or a sequence.')
randomrange = _randrange(seed)
# start with the identity permutation
result = Permutation(list(range(self.degree)))
m = len(self)
for _ in range(n):
p = self[randomrange(m)]
result = rmul(result, p)
return result
def random(self, af=False):
"""Return a random group element
"""
rank = randrange(self.order())
return self.coset_unrank(rank, af)
def random_pr(self, gen_count=11, iterations=50, _random_prec=None):
"""Return a random group element using product replacement.
Explanation
===========
For the details of the product replacement algorithm, see
``_random_pr_init`` In ``random_pr`` the actual 'product replacement'
is performed. Notice that if the attribute ``_random_gens``
is empty, it needs to be initialized by ``_random_pr_init``.
See Also
========
_random_pr_init
"""
if self._random_gens == []:
self._random_pr_init(gen_count, iterations)
random_gens = self._random_gens
r = len(random_gens) - 1
# handle randomized input for testing purposes
if _random_prec is None:
s = randrange(r)
t = randrange(r - 1)
if t == s:
t = r - 1
x = choice([1, 2])
e = choice([-1, 1])
else:
s = _random_prec['s']
t = _random_prec['t']
if t == s:
t = r - 1
x = _random_prec['x']
e = _random_prec['e']
if x == 1:
random_gens[s] = _af_rmul(random_gens[s], _af_pow(random_gens[t], e))
random_gens[r] = _af_rmul(random_gens[r], random_gens[s])
else:
random_gens[s] = _af_rmul(_af_pow(random_gens[t], e), random_gens[s])
random_gens[r] = _af_rmul(random_gens[s], random_gens[r])
return _af_new(random_gens[r])
def random_stab(self, alpha, schreier_vector=None, _random_prec=None):
"""Random element from the stabilizer of ``alpha``.
The schreier vector for ``alpha`` is an optional argument used
for speeding up repeated calls. The algorithm is described in [1], p.81
See Also
========
random_pr, orbit_rep
"""
if schreier_vector is None:
schreier_vector = self.schreier_vector(alpha)
if _random_prec is None:
rand = self.random_pr()
else:
rand = _random_prec['rand']
beta = rand(alpha)
h = self.orbit_rep(alpha, beta, schreier_vector)
return rmul(~h, rand)
def schreier_sims(self):
"""Schreier-Sims algorithm.
Explanation
===========
It computes the generators of the chain of stabilizers
`G > G_{b_1} > .. > G_{b1,..,b_r} > 1`
in which `G_{b_1,..,b_i}` stabilizes `b_1,..,b_i`,
and the corresponding ``s`` cosets.
An element of the group can be written as the product
`h_1*..*h_s`.
We use the incremental Schreier-Sims algorithm.
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> a = Permutation([0, 2, 1])
>>> b = Permutation([1, 0, 2])
>>> G = PermutationGroup([a, b])
>>> G.schreier_sims()
>>> G.basic_transversals
[{0: (2)(0 1), 1: (2), 2: (1 2)},
{0: (2), 2: (0 2)}]
"""
if self._transversals:
return
self._schreier_sims()
return
def _schreier_sims(self, base=None):
schreier = self.schreier_sims_incremental(base=base, slp_dict=True)
base, strong_gens = schreier[:2]
self._base = base
self._strong_gens = strong_gens
self._strong_gens_slp = schreier[2]
if not base:
self._transversals = []
self._basic_orbits = []
return
strong_gens_distr = _distribute_gens_by_base(base, strong_gens)
basic_orbits, transversals, slps = _orbits_transversals_from_bsgs(base,\
strong_gens_distr, slp=True)
# rewrite the indices stored in slps in terms of strong_gens
for i, slp in enumerate(slps):
gens = strong_gens_distr[i]
for k in slp:
slp[k] = [strong_gens.index(gens[s]) for s in slp[k]]
self._transversals = transversals
self._basic_orbits = [sorted(x) for x in basic_orbits]
self._transversal_slp = slps
def schreier_sims_incremental(self, base=None, gens=None, slp_dict=False):
"""Extend a sequence of points and generating set to a base and strong
generating set.
Parameters
==========
base
The sequence of points to be extended to a base. Optional
parameter with default value ``[]``.
gens
The generating set to be extended to a strong generating set
relative to the base obtained. Optional parameter with default
value ``self.generators``.
slp_dict
If `True`, return a dictionary `{g: gens}` for each strong
generator `g` where `gens` is a list of strong generators
coming before `g` in `strong_gens`, such that the product
of the elements of `gens` is equal to `g`.
Returns
=======
(base, strong_gens)
``base`` is the base obtained, and ``strong_gens`` is the strong
generating set relative to it. The original parameters ``base``,
``gens`` remain unchanged.
Examples
========
>>> from sympy.combinatorics.named_groups import AlternatingGroup
>>> from sympy.combinatorics.testutil import _verify_bsgs
>>> A = AlternatingGroup(7)
>>> base = [2, 3]
>>> seq = [2, 3]
>>> base, strong_gens = A.schreier_sims_incremental(base=seq)
>>> _verify_bsgs(A, base, strong_gens)
True
>>> base[:2]
[2, 3]
Notes
=====
This version of the Schreier-Sims algorithm runs in polynomial time.
There are certain assumptions in the implementation - if the trivial
group is provided, ``base`` and ``gens`` are returned immediately,
as any sequence of points is a base for the trivial group. If the
identity is present in the generators ``gens``, it is removed as
it is a redundant generator.
The implementation is described in [1], pp. 90-93.
See Also
========
schreier_sims, schreier_sims_random
"""
if base is None:
base = []
if gens is None:
gens = self.generators[:]
degree = self.degree
id_af = list(range(degree))
# handle the trivial group
if len(gens) == 1 and gens[0].is_Identity:
if slp_dict:
return base, gens, {gens[0]: [gens[0]]}
return base, gens
# prevent side effects
_base, _gens = base[:], gens[:]
# remove the identity as a generator
_gens = [x for x in _gens if not x.is_Identity]
# make sure no generator fixes all base points
for gen in _gens:
if all(x == gen._array_form[x] for x in _base):
for new in id_af:
if gen._array_form[new] != new:
break
else:
assert None # can this ever happen?
_base.append(new)
# distribute generators according to basic stabilizers
strong_gens_distr = _distribute_gens_by_base(_base, _gens)
strong_gens_slp = []
# initialize the basic stabilizers, basic orbits and basic transversals
orbs = {}
transversals = {}
slps = {}
base_len = len(_base)
for i in range(base_len):
transversals[i], slps[i] = _orbit_transversal(degree, strong_gens_distr[i],
_base[i], pairs=True, af=True, slp=True)
transversals[i] = dict(transversals[i])
orbs[i] = list(transversals[i].keys())
# main loop: amend the stabilizer chain until we have generators
# for all stabilizers
i = base_len - 1
while i >= 0:
# this flag is used to continue with the main loop from inside
# a nested loop
continue_i = False
# test the generators for being a strong generating set
db = {}
for beta, u_beta in list(transversals[i].items()):
for j, gen in enumerate(strong_gens_distr[i]):
gb = gen._array_form[beta]
u1 = transversals[i][gb]
g1 = _af_rmul(gen._array_form, u_beta)
slp = [(i, g) for g in slps[i][beta]]
slp = [(i, j)] + slp
if g1 != u1:
# test if the schreier generator is in the i+1-th
# would-be basic stabilizer
y = True
try:
u1_inv = db[gb]
except KeyError:
u1_inv = db[gb] = _af_invert(u1)
schreier_gen = _af_rmul(u1_inv, g1)
u1_inv_slp = slps[i][gb][:]
u1_inv_slp.reverse()
u1_inv_slp = [(i, (g,)) for g in u1_inv_slp]
slp = u1_inv_slp + slp
h, j, slp = _strip_af(schreier_gen, _base, orbs, transversals, i, slp=slp, slps=slps)
if j <= base_len:
# new strong generator h at level j
y = False
elif h:
# h fixes all base points
y = False
moved = 0
while h[moved] == moved:
moved += 1
_base.append(moved)
base_len += 1
strong_gens_distr.append([])
if y is False:
# if a new strong generator is found, update the
# data structures and start over
h = _af_new(h)
strong_gens_slp.append((h, slp))
for l in range(i + 1, j):
strong_gens_distr[l].append(h)
transversals[l], slps[l] =\
_orbit_transversal(degree, strong_gens_distr[l],
_base[l], pairs=True, af=True, slp=True)
transversals[l] = dict(transversals[l])
orbs[l] = list(transversals[l].keys())
i = j - 1
# continue main loop using the flag
continue_i = True
if continue_i is True:
break
if continue_i is True:
break
if continue_i is True:
continue
i -= 1
strong_gens = _gens[:]
if slp_dict:
# create the list of the strong generators strong_gens and
# rewrite the indices of strong_gens_slp in terms of the
# elements of strong_gens
for k, slp in strong_gens_slp:
strong_gens.append(k)
for i in range(len(slp)):
s = slp[i]
if isinstance(s[1], tuple):
slp[i] = strong_gens_distr[s[0]][s[1][0]]**-1
else:
slp[i] = strong_gens_distr[s[0]][s[1]]
strong_gens_slp = dict(strong_gens_slp)
# add the original generators
for g in _gens:
strong_gens_slp[g] = [g]
return (_base, strong_gens, strong_gens_slp)
strong_gens.extend([k for k, _ in strong_gens_slp])
return _base, strong_gens
def schreier_sims_random(self, base=None, gens=None, consec_succ=10,
_random_prec=None):
r"""Randomized Schreier-Sims algorithm.
Explanation
===========
The randomized Schreier-Sims algorithm takes the sequence ``base``
and the generating set ``gens``, and extends ``base`` to a base, and
``gens`` to a strong generating set relative to that base with
probability of a wrong answer at most `2^{-consec\_succ}`,
provided the random generators are sufficiently random.
Parameters
==========
base
The sequence to be extended to a base.
gens
The generating set to be extended to a strong generating set.
consec_succ
The parameter defining the probability of a wrong answer.
_random_prec
An internal parameter used for testing purposes.
Returns
=======
(base, strong_gens)
``base`` is the base and ``strong_gens`` is the strong generating
set relative to it.
Examples
========
>>> from sympy.combinatorics.testutil import _verify_bsgs
>>> from sympy.combinatorics.named_groups import SymmetricGroup
>>> S = SymmetricGroup(5)
>>> base, strong_gens = S.schreier_sims_random(consec_succ=5)
>>> _verify_bsgs(S, base, strong_gens) #doctest: +SKIP
True
Notes
=====
The algorithm is described in detail in [1], pp. 97-98. It extends
the orbits ``orbs`` and the permutation groups ``stabs`` to
basic orbits and basic stabilizers for the base and strong generating
set produced in the end.
The idea of the extension process
is to "sift" random group elements through the stabilizer chain
and amend the stabilizers/orbits along the way when a sift
is not successful.
The helper function ``_strip`` is used to attempt
to decompose a random group element according to the current
state of the stabilizer chain and report whether the element was
fully decomposed (successful sift) or not (unsuccessful sift). In
the latter case, the level at which the sift failed is reported and
used to amend ``stabs``, ``base``, ``gens`` and ``orbs`` accordingly.
The halting condition is for ``consec_succ`` consecutive successful
sifts to pass. This makes sure that the current ``base`` and ``gens``
form a BSGS with probability at least `1 - 1/\text{consec\_succ}`.
See Also
========
schreier_sims
"""
if base is None:
base = []
if gens is None:
gens = self.generators
base_len = len(base)
n = self.degree
# make sure no generator fixes all base points
for gen in gens:
if all(gen(x) == x for x in base):
new = 0
while gen._array_form[new] == new:
new += 1
base.append(new)
base_len += 1
# distribute generators according to basic stabilizers
strong_gens_distr = _distribute_gens_by_base(base, gens)
# initialize the basic stabilizers, basic transversals and basic orbits
transversals = {}
orbs = {}
for i in range(base_len):
transversals[i] = dict(_orbit_transversal(n, strong_gens_distr[i],
base[i], pairs=True))
orbs[i] = list(transversals[i].keys())
# initialize the number of consecutive elements sifted
c = 0
# start sifting random elements while the number of consecutive sifts
# is less than consec_succ
while c < consec_succ:
if _random_prec is None:
g = self.random_pr()
else:
g = _random_prec['g'].pop()
h, j = _strip(g, base, orbs, transversals)
y = True
# determine whether a new base point is needed
if j <= base_len:
y = False
elif not h.is_Identity:
y = False
moved = 0
while h(moved) == moved:
moved += 1
base.append(moved)
base_len += 1
strong_gens_distr.append([])
# if the element doesn't sift, amend the strong generators and
# associated stabilizers and orbits
if y is False:
for l in range(1, j):
strong_gens_distr[l].append(h)
transversals[l] = dict(_orbit_transversal(n,
strong_gens_distr[l], base[l], pairs=True))
orbs[l] = list(transversals[l].keys())
c = 0
else:
c += 1
# build the strong generating set
strong_gens = strong_gens_distr[0][:]
for gen in strong_gens_distr[1]:
if gen not in strong_gens:
strong_gens.append(gen)
return base, strong_gens
def schreier_vector(self, alpha):
"""Computes the schreier vector for ``alpha``.
Explanation
===========
The Schreier vector efficiently stores information
about the orbit of ``alpha``. It can later be used to quickly obtain
elements of the group that send ``alpha`` to a particular element
in the orbit. Notice that the Schreier vector depends on the order
in which the group generators are listed. For a definition, see [3].
Since list indices start from zero, we adopt the convention to use
"None" instead of 0 to signify that an element does not belong
to the orbit.
For the algorithm and its correctness, see [2], pp.78-80.
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> a = Permutation([2, 4, 6, 3, 1, 5, 0])
>>> b = Permutation([0, 1, 3, 5, 4, 6, 2])
>>> G = PermutationGroup([a, b])
>>> G.schreier_vector(0)
[-1, None, 0, 1, None, 1, 0]
See Also
========
orbit
"""
n = self.degree
v = [None]*n
v[alpha] = -1
orb = [alpha]
used = [False]*n
used[alpha] = True
gens = self.generators
r = len(gens)
for b in orb:
for i in range(r):
temp = gens[i]._array_form[b]
if used[temp] is False:
orb.append(temp)
used[temp] = True
v[temp] = i
return v
def stabilizer(self, alpha):
r"""Return the stabilizer subgroup of ``alpha``.
Explanation
===========
The stabilizer of `\alpha` is the group `G_\alpha =
\{g \in G | g(\alpha) = \alpha\}`.
For a proof of correctness, see [1], p.79.
Examples
========
>>> from sympy.combinatorics.named_groups import DihedralGroup
>>> G = DihedralGroup(6)
>>> G.stabilizer(5)
PermutationGroup([
(5)(0 4)(1 3)])
See Also
========
orbit
"""
return PermGroup(_stabilizer(self._degree, self._generators, alpha))
@property
def strong_gens(self):
r"""Return a strong generating set from the Schreier-Sims algorithm.
Explanation
===========
A generating set `S = \{g_1, g_2, \dots, g_t\}` for a permutation group
`G` is a strong generating set relative to the sequence of points
(referred to as a "base") `(b_1, b_2, \dots, b_k)` if, for
`1 \leq i \leq k` we have that the intersection of the pointwise
stabilizer `G^{(i+1)} := G_{b_1, b_2, \dots, b_i}` with `S` generates
the pointwise stabilizer `G^{(i+1)}`. The concepts of a base and
strong generating set and their applications are discussed in depth
in [1], pp. 87-89 and [2], pp. 55-57.
Examples
========
>>> from sympy.combinatorics.named_groups import DihedralGroup
>>> D = DihedralGroup(4)
>>> D.strong_gens
[(0 1 2 3), (0 3)(1 2), (1 3)]
>>> D.base
[0, 1]
See Also
========
base, basic_transversals, basic_orbits, basic_stabilizers
"""
if self._strong_gens == []:
self.schreier_sims()
return self._strong_gens
def subgroup(self, gens):
"""
Return the subgroup generated by `gens` which is a list of
elements of the group
"""
if not all(g in self for g in gens):
raise ValueError("The group does not contain the supplied generators")
G = PermutationGroup(gens)
return G
def subgroup_search(self, prop, base=None, strong_gens=None, tests=None,
init_subgroup=None):
"""Find the subgroup of all elements satisfying the property ``prop``.
Explanation
===========
This is done by a depth-first search with respect to base images that
uses several tests to prune the search tree.
Parameters
==========
prop
The property to be used. Has to be callable on group elements
and always return ``True`` or ``False``. It is assumed that
all group elements satisfying ``prop`` indeed form a subgroup.
base
A base for the supergroup.
strong_gens
A strong generating set for the supergroup.
tests
A list of callables of length equal to the length of ``base``.
These are used to rule out group elements by partial base images,
so that ``tests[l](g)`` returns False if the element ``g`` is known
not to satisfy prop base on where g sends the first ``l + 1`` base
points.
init_subgroup
if a subgroup of the sought group is
known in advance, it can be passed to the function as this
parameter.
Returns
=======
res
The subgroup of all elements satisfying ``prop``. The generating
set for this group is guaranteed to be a strong generating set
relative to the base ``base``.
Examples
========
>>> from sympy.combinatorics.named_groups import (SymmetricGroup,
... AlternatingGroup)
>>> from sympy.combinatorics.testutil import _verify_bsgs
>>> S = SymmetricGroup(7)
>>> prop_even = lambda x: x.is_even
>>> base, strong_gens = S.schreier_sims_incremental()
>>> G = S.subgroup_search(prop_even, base=base, strong_gens=strong_gens)
>>> G.is_subgroup(AlternatingGroup(7))
True
>>> _verify_bsgs(G, base, G.generators)
True
Notes
=====
This function is extremely lengthy and complicated and will require
some careful attention. The implementation is described in
[1], pp. 114-117, and the comments for the code here follow the lines
of the pseudocode in the book for clarity.
The complexity is exponential in general, since the search process by
itself visits all members of the supergroup. However, there are a lot
of tests which are used to prune the search tree, and users can define
their own tests via the ``tests`` parameter, so in practice, and for
some computations, it's not terrible.
A crucial part in the procedure is the frequent base change performed
(this is line 11 in the pseudocode) in order to obtain a new basic
stabilizer. The book mentiones that this can be done by using
``.baseswap(...)``, however the current implementation uses a more
straightforward way to find the next basic stabilizer - calling the
function ``.stabilizer(...)`` on the previous basic stabilizer.
"""
# initialize BSGS and basic group properties
def get_reps(orbits):
# get the minimal element in the base ordering
return [min(orbit, key = lambda x: base_ordering[x]) \
for orbit in orbits]
def update_nu(l):
temp_index = len(basic_orbits[l]) + 1 -\
len(res_basic_orbits_init_base[l])
# this corresponds to the element larger than all points
if temp_index >= len(sorted_orbits[l]):
nu[l] = base_ordering[degree]
else:
nu[l] = sorted_orbits[l][temp_index]
if base is None:
base, strong_gens = self.schreier_sims_incremental()
base_len = len(base)
degree = self.degree
identity = _af_new(list(range(degree)))
base_ordering = _base_ordering(base, degree)
# add an element larger than all points
base_ordering.append(degree)
# add an element smaller than all points
base_ordering.append(-1)
# compute BSGS-related structures
strong_gens_distr = _distribute_gens_by_base(base, strong_gens)
basic_orbits, transversals = _orbits_transversals_from_bsgs(base,
strong_gens_distr)
# handle subgroup initialization and tests
if init_subgroup is None:
init_subgroup = PermutationGroup([identity])
if tests is None:
trivial_test = lambda x: True
tests = []
for i in range(base_len):
tests.append(trivial_test)
# line 1: more initializations.
res = init_subgroup
f = base_len - 1
l = base_len - 1
# line 2: set the base for K to the base for G
res_base = base[:]
# line 3: compute BSGS and related structures for K
res_base, res_strong_gens = res.schreier_sims_incremental(
base=res_base)
res_strong_gens_distr = _distribute_gens_by_base(res_base,
res_strong_gens)
res_generators = res.generators
res_basic_orbits_init_base = \
[_orbit(degree, res_strong_gens_distr[i], res_base[i])\
for i in range(base_len)]
# initialize orbit representatives
orbit_reps = [None]*base_len
# line 4: orbit representatives for f-th basic stabilizer of K
orbits = _orbits(degree, res_strong_gens_distr[f])
orbit_reps[f] = get_reps(orbits)
# line 5: remove the base point from the representatives to avoid
# getting the identity element as a generator for K
orbit_reps[f].remove(base[f])
# line 6: more initializations
c = [0]*base_len
u = [identity]*base_len
sorted_orbits = [None]*base_len
for i in range(base_len):
sorted_orbits[i] = basic_orbits[i][:]
sorted_orbits[i].sort(key=lambda point: base_ordering[point])
# line 7: initializations
mu = [None]*base_len
nu = [None]*base_len
# this corresponds to the element smaller than all points
mu[l] = degree + 1
update_nu(l)
# initialize computed words
computed_words = [identity]*base_len
# line 8: main loop
while True:
# apply all the tests
while l < base_len - 1 and \
computed_words[l](base[l]) in orbit_reps[l] and \
base_ordering[mu[l]] < \
base_ordering[computed_words[l](base[l])] < \
base_ordering[nu[l]] and \
tests[l](computed_words):
# line 11: change the (partial) base of K
new_point = computed_words[l](base[l])
res_base[l] = new_point
new_stab_gens = _stabilizer(degree, res_strong_gens_distr[l],
new_point)
res_strong_gens_distr[l + 1] = new_stab_gens
# line 12: calculate minimal orbit representatives for the
# l+1-th basic stabilizer
orbits = _orbits(degree, new_stab_gens)
orbit_reps[l + 1] = get_reps(orbits)
# line 13: amend sorted orbits
l += 1
temp_orbit = [computed_words[l - 1](point) for point
in basic_orbits[l]]
temp_orbit.sort(key=lambda point: base_ordering[point])
sorted_orbits[l] = temp_orbit
# lines 14 and 15: update variables used minimality tests
new_mu = degree + 1
for i in range(l):
if base[l] in res_basic_orbits_init_base[i]:
candidate = computed_words[i](base[i])
if base_ordering[candidate] > base_ordering[new_mu]:
new_mu = candidate
mu[l] = new_mu
update_nu(l)
# line 16: determine the new transversal element
c[l] = 0
temp_point = sorted_orbits[l][c[l]]
gamma = computed_words[l - 1]._array_form.index(temp_point)
u[l] = transversals[l][gamma]
# update computed words
computed_words[l] = rmul(computed_words[l - 1], u[l])
# lines 17 & 18: apply the tests to the group element found
g = computed_words[l]
temp_point = g(base[l])
if l == base_len - 1 and \
base_ordering[mu[l]] < \
base_ordering[temp_point] < base_ordering[nu[l]] and \
temp_point in orbit_reps[l] and \
tests[l](computed_words) and \
prop(g):
# line 19: reset the base of K
res_generators.append(g)
res_base = base[:]
# line 20: recalculate basic orbits (and transversals)
res_strong_gens.append(g)
res_strong_gens_distr = _distribute_gens_by_base(res_base,
res_strong_gens)
res_basic_orbits_init_base = \
[_orbit(degree, res_strong_gens_distr[i], res_base[i]) \
for i in range(base_len)]
# line 21: recalculate orbit representatives
# line 22: reset the search depth
orbit_reps[f] = get_reps(orbits)
l = f
# line 23: go up the tree until in the first branch not fully
# searched
while l >= 0 and c[l] == len(basic_orbits[l]) - 1:
l = l - 1
# line 24: if the entire tree is traversed, return K
if l == -1:
return PermutationGroup(res_generators)
# lines 25-27: update orbit representatives
if l < f:
# line 26
f = l
c[l] = 0
# line 27
temp_orbits = _orbits(degree, res_strong_gens_distr[f])
orbit_reps[f] = get_reps(temp_orbits)
# line 28: update variables used for minimality testing
mu[l] = degree + 1
temp_index = len(basic_orbits[l]) + 1 - \
len(res_basic_orbits_init_base[l])
if temp_index >= len(sorted_orbits[l]):
nu[l] = base_ordering[degree]
else:
nu[l] = sorted_orbits[l][temp_index]
# line 29: set the next element from the current branch and update
# accordingly
c[l] += 1
if l == 0:
gamma = sorted_orbits[l][c[l]]
else:
gamma = computed_words[l - 1]._array_form.index(sorted_orbits[l][c[l]])
u[l] = transversals[l][gamma]
if l == 0:
computed_words[l] = u[l]
else:
computed_words[l] = rmul(computed_words[l - 1], u[l])
@property
def transitivity_degree(self):
r"""Compute the degree of transitivity of the group.
Explanation
===========
A permutation group `G` acting on `\Omega = \{0, 1, \dots, n-1\}` is
``k``-fold transitive, if, for any `k` points
`(a_1, a_2, \dots, a_k) \in \Omega` and any `k` points
`(b_1, b_2, \dots, b_k) \in \Omega` there exists `g \in G` such that
`g(a_1) = b_1, g(a_2) = b_2, \dots, g(a_k) = b_k`
The degree of transitivity of `G` is the maximum ``k`` such that
`G` is ``k``-fold transitive. ([8])
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> a = Permutation([1, 2, 0])
>>> b = Permutation([1, 0, 2])
>>> G = PermutationGroup([a, b])
>>> G.transitivity_degree
3
See Also
========
is_transitive, orbit
"""
if self._transitivity_degree is None:
n = self.degree
G = self
# if G is k-transitive, a tuple (a_0,..,a_k)
# can be brought to (b_0,...,b_(k-1), b_k)
# where b_0,...,b_(k-1) are fixed points;
# consider the group G_k which stabilizes b_0,...,b_(k-1)
# if G_k is transitive on the subset excluding b_0,...,b_(k-1)
# then G is (k+1)-transitive
for i in range(n):
orb = G.orbit(i)
if len(orb) != n - i:
self._transitivity_degree = i
return i
G = G.stabilizer(i)
self._transitivity_degree = n
return n
else:
return self._transitivity_degree
def _p_elements_group(self, p):
'''
For an abelian p-group, return the subgroup consisting of
all elements of order p (and the identity)
'''
gens = self.generators[:]
gens = sorted(gens, key=lambda x: x.order(), reverse=True)
gens_p = [g**(g.order()/p) for g in gens]
gens_r = []
for i in range(len(gens)):
x = gens[i]
x_order = x.order()
# x_p has order p
x_p = x**(x_order/p)
if i > 0:
P = PermutationGroup(gens_p[:i])
else:
P = PermutationGroup(self.identity)
if x**(x_order/p) not in P:
gens_r.append(x**(x_order/p))
else:
# replace x by an element of order (x.order()/p)
# so that gens still generates G
g = P.generator_product(x_p, original=True)
for s in g:
x = x*s**-1
x_order = x_order/p
# insert x to gens so that the sorting is preserved
del gens[i]
del gens_p[i]
j = i - 1
while j < len(gens) and gens[j].order() >= x_order:
j += 1
gens = gens[:j] + [x] + gens[j:]
gens_p = gens_p[:j] + [x] + gens_p[j:]
return PermutationGroup(gens_r)
def _sylow_alt_sym(self, p):
'''
Return a p-Sylow subgroup of a symmetric or an
alternating group.
Explanation
===========
The algorithm for this is hinted at in [1], Chapter 4,
Exercise 4.
For Sym(n) with n = p^i, the idea is as follows. Partition
the interval [0..n-1] into p equal parts, each of length p^(i-1):
[0..p^(i-1)-1], [p^(i-1)..2*p^(i-1)-1]...[(p-1)*p^(i-1)..p^i-1].
Find a p-Sylow subgroup of Sym(p^(i-1)) (treated as a subgroup
of ``self``) acting on each of the parts. Call the subgroups
P_1, P_2...P_p. The generators for the subgroups P_2...P_p
can be obtained from those of P_1 by applying a "shifting"
permutation to them, that is, a permutation mapping [0..p^(i-1)-1]
to the second part (the other parts are obtained by using the shift
multiple times). The union of this permutation and the generators
of P_1 is a p-Sylow subgroup of ``self``.
For n not equal to a power of p, partition
[0..n-1] in accordance with how n would be written in base p.
E.g. for p=2 and n=11, 11 = 2^3 + 2^2 + 1 so the partition
is [[0..7], [8..9], {10}]. To generate a p-Sylow subgroup,
take the union of the generators for each of the parts.
For the above example, {(0 1), (0 2)(1 3), (0 4), (1 5)(2 7)}
from the first part, {(8 9)} from the second part and
nothing from the third. This gives 4 generators in total, and
the subgroup they generate is p-Sylow.
Alternating groups are treated the same except when p=2. In this
case, (0 1)(s s+1) should be added for an appropriate s (the start
of a part) for each part in the partitions.
See Also
========
sylow_subgroup, is_alt_sym
'''
n = self.degree
gens = []
identity = Permutation(n-1)
# the case of 2-sylow subgroups of alternating groups
# needs special treatment
alt = p == 2 and all(g.is_even for g in self.generators)
# find the presentation of n in base p
coeffs = []
m = n
while m > 0:
coeffs.append(m % p)
m = m // p
power = len(coeffs)-1
# for a symmetric group, gens[:i] is the generating
# set for a p-Sylow subgroup on [0..p**(i-1)-1]. For
# alternating groups, the same is given by gens[:2*(i-1)]
for i in range(1, power+1):
if i == 1 and alt:
# (0 1) shouldn't be added for alternating groups
continue
gen = Permutation([(j + p**(i-1)) % p**i for j in range(p**i)])
gens.append(identity*gen)
if alt:
gen = Permutation(0, 1)*gen*Permutation(0, 1)*gen
gens.append(gen)
# the first point in the current part (see the algorithm
# description in the docstring)
start = 0
while power > 0:
a = coeffs[power]
# make the permutation shifting the start of the first
# part ([0..p^i-1] for some i) to the current one
for _ in range(a):
shift = Permutation()
if start > 0:
for i in range(p**power):
shift = shift(i, start + i)
if alt:
gen = Permutation(0, 1)*shift*Permutation(0, 1)*shift
gens.append(gen)
j = 2*(power - 1)
else:
j = power
for i, gen in enumerate(gens[:j]):
if alt and i % 2 == 1:
continue
# shift the generator to the start of the
# partition part
gen = shift*gen*shift
gens.append(gen)
start += p**power
power = power-1
return gens
def sylow_subgroup(self, p):
'''
Return a p-Sylow subgroup of the group.
The algorithm is described in [1], Chapter 4, Section 7
Examples
========
>>> from sympy.combinatorics.named_groups import DihedralGroup
>>> from sympy.combinatorics.named_groups import SymmetricGroup
>>> from sympy.combinatorics.named_groups import AlternatingGroup
>>> D = DihedralGroup(6)
>>> S = D.sylow_subgroup(2)
>>> S.order()
4
>>> G = SymmetricGroup(6)
>>> S = G.sylow_subgroup(5)
>>> S.order()
5
>>> G1 = AlternatingGroup(3)
>>> G2 = AlternatingGroup(5)
>>> G3 = AlternatingGroup(9)
>>> S1 = G1.sylow_subgroup(3)
>>> S2 = G2.sylow_subgroup(3)
>>> S3 = G3.sylow_subgroup(3)
>>> len1 = len(S1.lower_central_series())
>>> len2 = len(S2.lower_central_series())
>>> len3 = len(S3.lower_central_series())
>>> len1 == len2
True
>>> len1 < len3
True
'''
from sympy.combinatorics.homomorphisms import (
orbit_homomorphism, block_homomorphism)
if not isprime(p):
raise ValueError("p must be a prime")
def is_p_group(G):
# check if the order of G is a power of p
# and return the power
m = G.order()
n = 0
while m % p == 0:
m = m/p
n += 1
if m == 1:
return True, n
return False, n
def _sylow_reduce(mu, nu):
# reduction based on two homomorphisms
# mu and nu with trivially intersecting
# kernels
Q = mu.image().sylow_subgroup(p)
Q = mu.invert_subgroup(Q)
nu = nu.restrict_to(Q)
R = nu.image().sylow_subgroup(p)
return nu.invert_subgroup(R)
order = self.order()
if order % p != 0:
return PermutationGroup([self.identity])
p_group, n = is_p_group(self)
if p_group:
return self
if self.is_alt_sym():
return PermutationGroup(self._sylow_alt_sym(p))
# if there is a non-trivial orbit with size not divisible
# by p, the sylow subgroup is contained in its stabilizer
# (by orbit-stabilizer theorem)
orbits = self.orbits()
non_p_orbits = [o for o in orbits if len(o) % p != 0 and len(o) != 1]
if non_p_orbits:
G = self.stabilizer(list(non_p_orbits[0]).pop())
return G.sylow_subgroup(p)
if not self.is_transitive():
# apply _sylow_reduce to orbit actions
orbits = sorted(orbits, key=len)
omega1 = orbits.pop()
omega2 = orbits[0].union(*orbits)
mu = orbit_homomorphism(self, omega1)
nu = orbit_homomorphism(self, omega2)
return _sylow_reduce(mu, nu)
blocks = self.minimal_blocks()
if len(blocks) > 1:
# apply _sylow_reduce to block system actions
mu = block_homomorphism(self, blocks[0])
nu = block_homomorphism(self, blocks[1])
return _sylow_reduce(mu, nu)
elif len(blocks) == 1:
block = list(blocks)[0]
if any(e != 0 for e in block):
# self is imprimitive
mu = block_homomorphism(self, block)
if not is_p_group(mu.image())[0]:
S = mu.image().sylow_subgroup(p)
return mu.invert_subgroup(S).sylow_subgroup(p)
# find an element of order p
g = self.random()
g_order = g.order()
while g_order % p != 0 or g_order == 0:
g = self.random()
g_order = g.order()
g = g**(g_order // p)
if order % p**2 != 0:
return PermutationGroup(g)
C = self.centralizer(g)
while C.order() % p**n != 0:
S = C.sylow_subgroup(p)
s_order = S.order()
Z = S.center()
P = Z._p_elements_group(p)
h = P.random()
C_h = self.centralizer(h)
while C_h.order() % p*s_order != 0:
h = P.random()
C_h = self.centralizer(h)
C = C_h
return C.sylow_subgroup(p)
def _block_verify(self, L, alpha):
delta = sorted(self.orbit(alpha))
# p[i] will be the number of the block
# delta[i] belongs to
p = [-1]*len(delta)
blocks = [-1]*len(delta)
B = [[]] # future list of blocks
u = [0]*len(delta) # u[i] in L s.t. alpha^u[i] = B[0][i]
t = L.orbit_transversal(alpha, pairs=True)
for a, beta in t:
B[0].append(a)
i_a = delta.index(a)
p[i_a] = 0
blocks[i_a] = alpha
u[i_a] = beta
rho = 0
m = 0 # number of blocks - 1
while rho <= m:
beta = B[rho][0]
for g in self.generators:
d = beta^g
i_d = delta.index(d)
sigma = p[i_d]
if sigma < 0:
# define a new block
m += 1
sigma = m
u[i_d] = u[delta.index(beta)]*g
p[i_d] = sigma
rep = d
blocks[i_d] = rep
newb = [rep]
for gamma in B[rho][1:]:
i_gamma = delta.index(gamma)
d = gamma^g
i_d = delta.index(d)
if p[i_d] < 0:
u[i_d] = u[i_gamma]*g
p[i_d] = sigma
blocks[i_d] = rep
newb.append(d)
else:
# B[rho] is not a block
s = u[i_gamma]*g*u[i_d]**(-1)
return False, s
B.append(newb)
else:
for h in B[rho][1:]:
if h^g not in B[sigma]:
# B[rho] is not a block
s = u[delta.index(beta)]*g*u[i_d]**(-1)
return False, s
rho += 1
return True, blocks
def _verify(H, K, phi, z, alpha):
'''
Return a list of relators ``rels`` in generators ``gens`_h` that
are mapped to ``H.generators`` by ``phi`` so that given a finite
presentation <gens_k | rels_k> of ``K`` on a subset of ``gens_h``
<gens_h | rels_k + rels> is a finite presentation of ``H``.
Explanation
===========
``H`` should be generated by the union of ``K.generators`` and ``z``
(a single generator), and ``H.stabilizer(alpha) == K``; ``phi`` is a
canonical injection from a free group into a permutation group
containing ``H``.
The algorithm is described in [1], Chapter 6.
Examples
========
>>> from sympy.combinatorics import free_group, Permutation, PermutationGroup
>>> from sympy.combinatorics.homomorphisms import homomorphism
>>> from sympy.combinatorics.fp_groups import FpGroup
>>> H = PermutationGroup(Permutation(0, 2), Permutation (1, 5))
>>> K = PermutationGroup(Permutation(5)(0, 2))
>>> F = free_group("x_0 x_1")[0]
>>> gens = F.generators
>>> phi = homomorphism(F, H, F.generators, H.generators)
>>> rels_k = [gens[0]**2] # relators for presentation of K
>>> z= Permutation(1, 5)
>>> check, rels_h = H._verify(K, phi, z, 1)
>>> check
True
>>> rels = rels_k + rels_h
>>> G = FpGroup(F, rels) # presentation of H
>>> G.order() == H.order()
True
See also
========
strong_presentation, presentation, stabilizer
'''
orbit = H.orbit(alpha)
beta = alpha^(z**-1)
K_beta = K.stabilizer(beta)
# orbit representatives of K_beta
gammas = [alpha, beta]
orbits = list({tuple(K_beta.orbit(o)) for o in orbit})
orbit_reps = [orb[0] for orb in orbits]
for rep in orbit_reps:
if rep not in gammas:
gammas.append(rep)
# orbit transversal of K
betas = [alpha, beta]
transversal = {alpha: phi.invert(H.identity), beta: phi.invert(z**-1)}
for s, g in K.orbit_transversal(beta, pairs=True):
if s not in transversal:
transversal[s] = transversal[beta]*phi.invert(g)
union = K.orbit(alpha).union(K.orbit(beta))
while (len(union) < len(orbit)):
for gamma in gammas:
if gamma in union:
r = gamma^z
if r not in union:
betas.append(r)
transversal[r] = transversal[gamma]*phi.invert(z)
for s, g in K.orbit_transversal(r, pairs=True):
if s not in transversal:
transversal[s] = transversal[r]*phi.invert(g)
union = union.union(K.orbit(r))
break
# compute relators
rels = []
for b in betas:
k_gens = K.stabilizer(b).generators
for y in k_gens:
new_rel = transversal[b]
gens = K.generator_product(y, original=True)
for g in gens[::-1]:
new_rel = new_rel*phi.invert(g)
new_rel = new_rel*transversal[b]**-1
perm = phi(new_rel)
try:
gens = K.generator_product(perm, original=True)
except ValueError:
return False, perm
for g in gens:
new_rel = new_rel*phi.invert(g)**-1
if new_rel not in rels:
rels.append(new_rel)
for gamma in gammas:
new_rel = transversal[gamma]*phi.invert(z)*transversal[gamma^z]**-1
perm = phi(new_rel)
try:
gens = K.generator_product(perm, original=True)
except ValueError:
return False, perm
for g in gens:
new_rel = new_rel*phi.invert(g)**-1
if new_rel not in rels:
rels.append(new_rel)
return True, rels
def strong_presentation(self):
'''
Return a strong finite presentation of group. The generators
of the returned group are in the same order as the strong
generators of group.
The algorithm is based on Sims' Verify algorithm described
in [1], Chapter 6.
Examples
========
>>> from sympy.combinatorics.named_groups import DihedralGroup
>>> P = DihedralGroup(4)
>>> G = P.strong_presentation()
>>> P.order() == G.order()
True
See Also
========
presentation, _verify
'''
from sympy.combinatorics.fp_groups import (FpGroup,
simplify_presentation)
from sympy.combinatorics.free_groups import free_group
from sympy.combinatorics.homomorphisms import (block_homomorphism,
homomorphism, GroupHomomorphism)
strong_gens = self.strong_gens[:]
stabs = self.basic_stabilizers[:]
base = self.base[:]
# injection from a free group on len(strong_gens)
# generators into G
gen_syms = [('x_%d'%i) for i in range(len(strong_gens))]
F = free_group(', '.join(gen_syms))[0]
phi = homomorphism(F, self, F.generators, strong_gens)
H = PermutationGroup(self.identity)
while stabs:
alpha = base.pop()
K = H
H = stabs.pop()
new_gens = [g for g in H.generators if g not in K]
if K.order() == 1:
z = new_gens.pop()
rels = [F.generators[-1]**z.order()]
intermediate_gens = [z]
K = PermutationGroup(intermediate_gens)
# add generators one at a time building up from K to H
while new_gens:
z = new_gens.pop()
intermediate_gens = [z] + intermediate_gens
K_s = PermutationGroup(intermediate_gens)
orbit = K_s.orbit(alpha)
orbit_k = K.orbit(alpha)
# split into cases based on the orbit of K_s
if orbit_k == orbit:
if z in K:
rel = phi.invert(z)
perm = z
else:
t = K.orbit_rep(alpha, alpha^z)
rel = phi.invert(z)*phi.invert(t)**-1
perm = z*t**-1
for g in K.generator_product(perm, original=True):
rel = rel*phi.invert(g)**-1
new_rels = [rel]
elif len(orbit_k) == 1:
# `success` is always true because `strong_gens`
# and `base` are already a verified BSGS. Later
# this could be changed to start with a randomly
# generated (potential) BSGS, and then new elements
# would have to be appended to it when `success`
# is false.
success, new_rels = K_s._verify(K, phi, z, alpha)
else:
# K.orbit(alpha) should be a block
# under the action of K_s on K_s.orbit(alpha)
check, block = K_s._block_verify(K, alpha)
if check:
# apply _verify to the action of K_s
# on the block system; for convenience,
# add the blocks as additional points
# that K_s should act on
t = block_homomorphism(K_s, block)
m = t.codomain.degree # number of blocks
d = K_s.degree
# conjugating with p will shift
# permutations in t.image() to
# higher numbers, e.g.
# p*(0 1)*p = (m m+1)
p = Permutation()
for i in range(m):
p *= Permutation(i, i+d)
t_img = t.images
# combine generators of K_s with their
# action on the block system
images = {g: g*p*t_img[g]*p for g in t_img}
for g in self.strong_gens[:-len(K_s.generators)]:
images[g] = g
K_s_act = PermutationGroup(list(images.values()))
f = GroupHomomorphism(self, K_s_act, images)
K_act = PermutationGroup([f(g) for g in K.generators])
success, new_rels = K_s_act._verify(K_act, f.compose(phi), f(z), d)
for n in new_rels:
if n not in rels:
rels.append(n)
K = K_s
group = FpGroup(F, rels)
return simplify_presentation(group)
def presentation(self, eliminate_gens=True):
'''
Return an `FpGroup` presentation of the group.
The algorithm is described in [1], Chapter 6.1.
'''
from sympy.combinatorics.fp_groups import (FpGroup,
simplify_presentation)
from sympy.combinatorics.coset_table import CosetTable
from sympy.combinatorics.free_groups import free_group
from sympy.combinatorics.homomorphisms import homomorphism
if self._fp_presentation:
return self._fp_presentation
def _factor_group_by_rels(G, rels):
if isinstance(G, FpGroup):
rels.extend(G.relators)
return FpGroup(G.free_group, list(set(rels)))
return FpGroup(G, rels)
gens = self.generators
len_g = len(gens)
if len_g == 1:
order = gens[0].order()
# handle the trivial group
if order == 1:
return free_group([])[0]
F, x = free_group('x')
return FpGroup(F, [x**order])
if self.order() > 20:
half_gens = self.generators[0:(len_g+1)//2]
else:
half_gens = []
H = PermutationGroup(half_gens)
H_p = H.presentation()
len_h = len(H_p.generators)
C = self.coset_table(H)
n = len(C) # subgroup index
gen_syms = [('x_%d'%i) for i in range(len(gens))]
F = free_group(', '.join(gen_syms))[0]
# mapping generators of H_p to those of F
images = [F.generators[i] for i in range(len_h)]
R = homomorphism(H_p, F, H_p.generators, images, check=False)
# rewrite relators
rels = R(H_p.relators)
G_p = FpGroup(F, rels)
# injective homomorphism from G_p into self
T = homomorphism(G_p, self, G_p.generators, gens)
C_p = CosetTable(G_p, [])
C_p.table = [[None]*(2*len_g) for i in range(n)]
# initiate the coset transversal
transversal = [None]*n
transversal[0] = G_p.identity
# fill in the coset table as much as possible
for i in range(2*len_h):
C_p.table[0][i] = 0
gamma = 1
for alpha, x in product(range(n), range(2*len_g)):
beta = C[alpha][x]
if beta == gamma:
gen = G_p.generators[x//2]**((-1)**(x % 2))
transversal[beta] = transversal[alpha]*gen
C_p.table[alpha][x] = beta
C_p.table[beta][x + (-1)**(x % 2)] = alpha
gamma += 1
if gamma == n:
break
C_p.p = list(range(n))
beta = x = 0
while not C_p.is_complete():
# find the first undefined entry
while C_p.table[beta][x] == C[beta][x]:
x = (x + 1) % (2*len_g)
if x == 0:
beta = (beta + 1) % n
# define a new relator
gen = G_p.generators[x//2]**((-1)**(x % 2))
new_rel = transversal[beta]*gen*transversal[C[beta][x]]**-1
perm = T(new_rel)
nxt = G_p.identity
for s in H.generator_product(perm, original=True):
nxt = nxt*T.invert(s)**-1
new_rel = new_rel*nxt
# continue coset enumeration
G_p = _factor_group_by_rels(G_p, [new_rel])
C_p.scan_and_fill(0, new_rel)
C_p = G_p.coset_enumeration([], strategy="coset_table",
draft=C_p, max_cosets=n, incomplete=True)
self._fp_presentation = simplify_presentation(G_p)
return self._fp_presentation
def polycyclic_group(self):
"""
Return the PolycyclicGroup instance with below parameters:
Explanation
===========
* pc_sequence : Polycyclic sequence is formed by collecting all
the missing generators between the adjacent groups in the
derived series of given permutation group.
* pc_series : Polycyclic series is formed by adding all the missing
generators of ``der[i+1]`` in ``der[i]``, where ``der`` represents
the derived series.
* relative_order : A list, computed by the ratio of adjacent groups in
pc_series.
"""
from sympy.combinatorics.pc_groups import PolycyclicGroup
if not self.is_polycyclic:
raise ValueError("The group must be solvable")
der = self.derived_series()
pc_series = []
pc_sequence = []
relative_order = []
pc_series.append(der[-1])
der.reverse()
for i in range(len(der)-1):
H = der[i]
for g in der[i+1].generators:
if g not in H:
H = PermutationGroup([g] + H.generators)
pc_series.insert(0, H)
pc_sequence.insert(0, g)
G1 = pc_series[0].order()
G2 = pc_series[1].order()
relative_order.insert(0, G1 // G2)
return PolycyclicGroup(pc_sequence, pc_series, relative_order, collector=None)
def _orbit(degree, generators, alpha, action='tuples'):
r"""Compute the orbit of alpha `\{g(\alpha) | g \in G\}` as a set.
Explanation
===========
The time complexity of the algorithm used here is `O(|Orb|*r)` where
`|Orb|` is the size of the orbit and ``r`` is the number of generators of
the group. For a more detailed analysis, see [1], p.78, [2], pp. 19-21.
Here alpha can be a single point, or a list of points.
If alpha is a single point, the ordinary orbit is computed.
if alpha is a list of points, there are three available options:
'union' - computes the union of the orbits of the points in the list
'tuples' - computes the orbit of the list interpreted as an ordered
tuple under the group action ( i.e., g((1, 2, 3)) = (g(1), g(2), g(3)) )
'sets' - computes the orbit of the list interpreted as a sets
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> from sympy.combinatorics.perm_groups import _orbit
>>> a = Permutation([1, 2, 0, 4, 5, 6, 3])
>>> G = PermutationGroup([a])
>>> _orbit(G.degree, G.generators, 0)
{0, 1, 2}
>>> _orbit(G.degree, G.generators, [0, 4], 'union')
{0, 1, 2, 3, 4, 5, 6}
See Also
========
orbit, orbit_transversal
"""
if not hasattr(alpha, '__getitem__'):
alpha = [alpha]
gens = [x._array_form for x in generators]
if len(alpha) == 1 or action == 'union':
orb = alpha
used = [False]*degree
for el in alpha:
used[el] = True
for b in orb:
for gen in gens:
temp = gen[b]
if used[temp] == False:
orb.append(temp)
used[temp] = True
return set(orb)
elif action == 'tuples':
alpha = tuple(alpha)
orb = [alpha]
used = {alpha}
for b in orb:
for gen in gens:
temp = tuple([gen[x] for x in b])
if temp not in used:
orb.append(temp)
used.add(temp)
return set(orb)
elif action == 'sets':
alpha = frozenset(alpha)
orb = [alpha]
used = {alpha}
for b in orb:
for gen in gens:
temp = frozenset([gen[x] for x in b])
if temp not in used:
orb.append(temp)
used.add(temp)
return {tuple(x) for x in orb}
def _orbits(degree, generators):
"""Compute the orbits of G.
If ``rep=False`` it returns a list of sets else it returns a list of
representatives of the orbits
Examples
========
>>> from sympy.combinatorics import Permutation
>>> from sympy.combinatorics.perm_groups import _orbits
>>> a = Permutation([0, 2, 1])
>>> b = Permutation([1, 0, 2])
>>> _orbits(a.size, [a, b])
[{0, 1, 2}]
"""
orbs = []
sorted_I = list(range(degree))
I = set(sorted_I)
while I:
i = sorted_I[0]
orb = _orbit(degree, generators, i)
orbs.append(orb)
# remove all indices that are in this orbit
I -= orb
sorted_I = [i for i in sorted_I if i not in orb]
return orbs
def _orbit_transversal(degree, generators, alpha, pairs, af=False, slp=False):
r"""Computes a transversal for the orbit of ``alpha`` as a set.
Explanation
===========
generators generators of the group ``G``
For a permutation group ``G``, a transversal for the orbit
`Orb = \{g(\alpha) | g \in G\}` is a set
`\{g_\beta | g_\beta(\alpha) = \beta\}` for `\beta \in Orb`.
Note that there may be more than one possible transversal.
If ``pairs`` is set to ``True``, it returns the list of pairs
`(\beta, g_\beta)`. For a proof of correctness, see [1], p.79
if ``af`` is ``True``, the transversal elements are given in
array form.
If `slp` is `True`, a dictionary `{beta: slp_beta}` is returned
for `\beta \in Orb` where `slp_beta` is a list of indices of the
generators in `generators` s.t. if `slp_beta = [i_1 \dots i_n]`
`g_\beta = generators[i_n] \times \dots \times generators[i_1]`.
Examples
========
>>> from sympy.combinatorics.named_groups import DihedralGroup
>>> from sympy.combinatorics.perm_groups import _orbit_transversal
>>> G = DihedralGroup(6)
>>> _orbit_transversal(G.degree, G.generators, 0, False)
[(5), (0 1 2 3 4 5), (0 5)(1 4)(2 3), (0 2 4)(1 3 5), (5)(0 4)(1 3), (0 3)(1 4)(2 5)]
"""
tr = [(alpha, list(range(degree)))]
slp_dict = {alpha: []}
used = [False]*degree
used[alpha] = True
gens = [x._array_form for x in generators]
for x, px in tr:
px_slp = slp_dict[x]
for gen in gens:
temp = gen[x]
if used[temp] == False:
slp_dict[temp] = [gens.index(gen)] + px_slp
tr.append((temp, _af_rmul(gen, px)))
used[temp] = True
if pairs:
if not af:
tr = [(x, _af_new(y)) for x, y in tr]
if not slp:
return tr
return tr, slp_dict
if af:
tr = [y for _, y in tr]
if not slp:
return tr
return tr, slp_dict
tr = [_af_new(y) for _, y in tr]
if not slp:
return tr
return tr, slp_dict
def _stabilizer(degree, generators, alpha):
r"""Return the stabilizer subgroup of ``alpha``.
Explanation
===========
The stabilizer of `\alpha` is the group `G_\alpha =
\{g \in G | g(\alpha) = \alpha\}`.
For a proof of correctness, see [1], p.79.
degree : degree of G
generators : generators of G
Examples
========
>>> from sympy.combinatorics.perm_groups import _stabilizer
>>> from sympy.combinatorics.named_groups import DihedralGroup
>>> G = DihedralGroup(6)
>>> _stabilizer(G.degree, G.generators, 5)
[(5)(0 4)(1 3), (5)]
See Also
========
orbit
"""
orb = [alpha]
table = {alpha: list(range(degree))}
table_inv = {alpha: list(range(degree))}
used = [False]*degree
used[alpha] = True
gens = [x._array_form for x in generators]
stab_gens = []
for b in orb:
for gen in gens:
temp = gen[b]
if used[temp] is False:
gen_temp = _af_rmul(gen, table[b])
orb.append(temp)
table[temp] = gen_temp
table_inv[temp] = _af_invert(gen_temp)
used[temp] = True
else:
schreier_gen = _af_rmuln(table_inv[temp], gen, table[b])
if schreier_gen not in stab_gens:
stab_gens.append(schreier_gen)
return [_af_new(x) for x in stab_gens]
PermGroup = PermutationGroup
class SymmetricPermutationGroup(Basic):
"""
The class defining the lazy form of SymmetricGroup.
deg : int
"""
def __new__(cls, deg):
deg = _sympify(deg)
obj = Basic.__new__(cls, deg)
return obj
def __init__(self, *args, **kwargs):
self._deg = self.args[0]
self._order = None
def __contains__(self, i):
"""Return ``True`` if *i* is contained in SymmetricPermutationGroup.
Examples
========
>>> from sympy.combinatorics import Permutation, SymmetricPermutationGroup
>>> G = SymmetricPermutationGroup(4)
>>> Permutation(1, 2, 3) in G
True
"""
if not isinstance(i, Permutation):
raise TypeError("A SymmetricPermutationGroup contains only Permutations as "
"elements, not elements of type %s" % type(i))
return i.size == self.degree
def order(self):
"""
Return the order of the SymmetricPermutationGroup.
Examples
========
>>> from sympy.combinatorics import SymmetricPermutationGroup
>>> G = SymmetricPermutationGroup(4)
>>> G.order()
24
"""
if self._order is not None:
return self._order
n = self._deg
self._order = factorial(n)
return self._order
@property
def degree(self):
"""
Return the degree of the SymmetricPermutationGroup.
Examples
========
>>> from sympy.combinatorics import SymmetricPermutationGroup
>>> G = SymmetricPermutationGroup(4)
>>> G.degree
4
"""
return self._deg
@property
def identity(self):
'''
Return the identity element of the SymmetricPermutationGroup.
Examples
========
>>> from sympy.combinatorics import SymmetricPermutationGroup
>>> G = SymmetricPermutationGroup(4)
>>> G.identity()
(3)
'''
return _af_new(list(range(self._deg)))
class Coset(Basic):
"""A left coset of a permutation group with respect to an element.
Parameters
==========
g : Permutation
H : PermutationGroup
dir : "+" or "-", If not specified by default it will be "+"
here ``dir`` specified the type of coset "+" represent the
right coset and "-" represent the left coset.
G : PermutationGroup, optional
The group which contains *H* as its subgroup and *g* as its
element.
If not specified, it would automatically become a symmetric
group ``SymmetricPermutationGroup(g.size)`` and
``SymmetricPermutationGroup(H.degree)`` if ``g.size`` and ``H.degree``
are matching.``SymmetricPermutationGroup`` is a lazy form of SymmetricGroup
used for representation purpose.
"""
def __new__(cls, g, H, G=None, dir="+"):
g = _sympify(g)
if not isinstance(g, Permutation):
raise NotImplementedError
H = _sympify(H)
if not isinstance(H, PermutationGroup):
raise NotImplementedError
if G is not None:
G = _sympify(G)
if not isinstance(G, (PermutationGroup, SymmetricPermutationGroup)):
raise NotImplementedError
if not H.is_subgroup(G):
raise ValueError("{} must be a subgroup of {}.".format(H, G))
if g not in G:
raise ValueError("{} must be an element of {}.".format(g, G))
else:
g_size = g.size
h_degree = H.degree
if g_size != h_degree:
raise ValueError(
"The size of the permutation {} and the degree of "
"the permutation group {} should be matching "
.format(g, H))
G = SymmetricPermutationGroup(g.size)
if isinstance(dir, str):
dir = Symbol(dir)
elif not isinstance(dir, Symbol):
raise TypeError("dir must be of type basestring or "
"Symbol, not %s" % type(dir))
if str(dir) not in ('+', '-'):
raise ValueError("dir must be one of '+' or '-' not %s" % dir)
obj = Basic.__new__(cls, g, H, G, dir)
return obj
def __init__(self, *args, **kwargs):
self._dir = self.args[3]
@property
def is_left_coset(self):
"""
Check if the coset is left coset that is ``gH``.
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup, Coset
>>> a = Permutation(1, 2)
>>> b = Permutation(0, 1)
>>> G = PermutationGroup([a, b])
>>> cst = Coset(a, G, dir="-")
>>> cst.is_left_coset
True
"""
return str(self._dir) == '-'
@property
def is_right_coset(self):
"""
Check if the coset is right coset that is ``Hg``.
Examples
========
>>> from sympy.combinatorics import Permutation, PermutationGroup, Coset
>>> a = Permutation(1, 2)
>>> b = Permutation(0, 1)
>>> G = PermutationGroup([a, b])
>>> cst = Coset(a, G, dir="+")
>>> cst.is_right_coset
True
"""
return str(self._dir) == '+'
def as_list(self):
"""
Return all the elements of coset in the form of list.
"""
g = self.args[0]
H = self.args[1]
cst = []
if str(self._dir) == '+':
for h in H.elements:
cst.append(h*g)
else:
for h in H.elements:
cst.append(g*h)
return cst
PK ]ZZZT@UD�V �V # sympy/combinatorics/permutations.pyimport random
from collections import defaultdict
from collections.abc import Iterable
from functools import reduce
from sympy.core.parameters import global_parameters
from sympy.core.basic import Atom
from sympy.core.expr import Expr
from sympy.core.numbers import int_valued
from sympy.core.numbers import Integer
from sympy.core.sympify import _sympify
from sympy.matrices import zeros
from sympy.polys.polytools import lcm
from sympy.printing.repr import srepr
from sympy.utilities.iterables import (flatten, has_variety, minlex,
has_dups, runs, is_sequence)
from sympy.utilities.misc import as_int
from mpmath.libmp.libintmath import ifac
from sympy.multipledispatch import dispatch
def _af_rmul(a, b):
"""
Return the product b*a; input and output are array forms. The ith value
is a[b[i]].
Examples
========
>>> from sympy.combinatorics.permutations import _af_rmul, Permutation
>>> a, b = [1, 0, 2], [0, 2, 1]
>>> _af_rmul(a, b)
[1, 2, 0]
>>> [a[b[i]] for i in range(3)]
[1, 2, 0]
This handles the operands in reverse order compared to the ``*`` operator:
>>> a = Permutation(a)
>>> b = Permutation(b)
>>> list(a*b)
[2, 0, 1]
>>> [b(a(i)) for i in range(3)]
[2, 0, 1]
See Also
========
rmul, _af_rmuln
"""
return [a[i] for i in b]
def _af_rmuln(*abc):
"""
Given [a, b, c, ...] return the product of ...*c*b*a using array forms.
The ith value is a[b[c[i]]].
Examples
========
>>> from sympy.combinatorics.permutations import _af_rmul, Permutation
>>> a, b = [1, 0, 2], [0, 2, 1]
>>> _af_rmul(a, b)
[1, 2, 0]
>>> [a[b[i]] for i in range(3)]
[1, 2, 0]
This handles the operands in reverse order compared to the ``*`` operator:
>>> a = Permutation(a); b = Permutation(b)
>>> list(a*b)
[2, 0, 1]
>>> [b(a(i)) for i in range(3)]
[2, 0, 1]
See Also
========
rmul, _af_rmul
"""
a = abc
m = len(a)
if m == 3:
p0, p1, p2 = a
return [p0[p1[i]] for i in p2]
if m == 4:
p0, p1, p2, p3 = a
return [p0[p1[p2[i]]] for i in p3]
if m == 5:
p0, p1, p2, p3, p4 = a
return [p0[p1[p2[p3[i]]]] for i in p4]
if m == 6:
p0, p1, p2, p3, p4, p5 = a
return [p0[p1[p2[p3[p4[i]]]]] for i in p5]
if m == 7:
p0, p1, p2, p3, p4, p5, p6 = a
return [p0[p1[p2[p3[p4[p5[i]]]]]] for i in p6]
if m == 8:
p0, p1, p2, p3, p4, p5, p6, p7 = a
return [p0[p1[p2[p3[p4[p5[p6[i]]]]]]] for i in p7]
if m == 1:
return a[0][:]
if m == 2:
a, b = a
return [a[i] for i in b]
if m == 0:
raise ValueError("String must not be empty")
p0 = _af_rmuln(*a[:m//2])
p1 = _af_rmuln(*a[m//2:])
return [p0[i] for i in p1]
def _af_parity(pi):
"""
Computes the parity of a permutation in array form.
Explanation
===========
The parity of a permutation reflects the parity of the
number of inversions in the permutation, i.e., the
number of pairs of x and y such that x > y but p[x] < p[y].
Examples
========
>>> from sympy.combinatorics.permutations import _af_parity
>>> _af_parity([0, 1, 2, 3])
0
>>> _af_parity([3, 2, 0, 1])
1
See Also
========
Permutation
"""
n = len(pi)
a = [0] * n
c = 0
for j in range(n):
if a[j] == 0:
c += 1
a[j] = 1
i = j
while pi[i] != j:
i = pi[i]
a[i] = 1
return (n - c) % 2
def _af_invert(a):
"""
Finds the inverse, ~A, of a permutation, A, given in array form.
Examples
========
>>> from sympy.combinatorics.permutations import _af_invert, _af_rmul
>>> A = [1, 2, 0, 3]
>>> _af_invert(A)
[2, 0, 1, 3]
>>> _af_rmul(_, A)
[0, 1, 2, 3]
See Also
========
Permutation, __invert__
"""
inv_form = [0] * len(a)
for i, ai in enumerate(a):
inv_form[ai] = i
return inv_form
def _af_pow(a, n):
"""
Routine for finding powers of a permutation.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> from sympy.combinatorics.permutations import _af_pow
>>> p = Permutation([2, 0, 3, 1])
>>> p.order()
4
>>> _af_pow(p._array_form, 4)
[0, 1, 2, 3]
"""
if n == 0:
return list(range(len(a)))
if n < 0:
return _af_pow(_af_invert(a), -n)
if n == 1:
return a[:]
elif n == 2:
b = [a[i] for i in a]
elif n == 3:
b = [a[a[i]] for i in a]
elif n == 4:
b = [a[a[a[i]]] for i in a]
else:
# use binary multiplication
b = list(range(len(a)))
while 1:
if n & 1:
b = [b[i] for i in a]
n -= 1
if not n:
break
if n % 4 == 0:
a = [a[a[a[i]]] for i in a]
n = n // 4
elif n % 2 == 0:
a = [a[i] for i in a]
n = n // 2
return b
def _af_commutes_with(a, b):
"""
Checks if the two permutations with array forms
given by ``a`` and ``b`` commute.
Examples
========
>>> from sympy.combinatorics.permutations import _af_commutes_with
>>> _af_commutes_with([1, 2, 0], [0, 2, 1])
False
See Also
========
Permutation, commutes_with
"""
return not any(a[b[i]] != b[a[i]] for i in range(len(a) - 1))
class Cycle(dict):
"""
Wrapper around dict which provides the functionality of a disjoint cycle.
Explanation
===========
A cycle shows the rule to use to move subsets of elements to obtain
a permutation. The Cycle class is more flexible than Permutation in
that 1) all elements need not be present in order to investigate how
multiple cycles act in sequence and 2) it can contain singletons:
>>> from sympy.combinatorics.permutations import Perm, Cycle
A Cycle will automatically parse a cycle given as a tuple on the rhs:
>>> Cycle(1, 2)(2, 3)
(1 3 2)
The identity cycle, Cycle(), can be used to start a product:
>>> Cycle()(1, 2)(2, 3)
(1 3 2)
The array form of a Cycle can be obtained by calling the list
method (or passing it to the list function) and all elements from
0 will be shown:
>>> a = Cycle(1, 2)
>>> a.list()
[0, 2, 1]
>>> list(a)
[0, 2, 1]
If a larger (or smaller) range is desired use the list method and
provide the desired size -- but the Cycle cannot be truncated to
a size smaller than the largest element that is out of place:
>>> b = Cycle(2, 4)(1, 2)(3, 1, 4)(1, 3)
>>> b.list()
[0, 2, 1, 3, 4]
>>> b.list(b.size + 1)
[0, 2, 1, 3, 4, 5]
>>> b.list(-1)
[0, 2, 1]
Singletons are not shown when printing with one exception: the largest
element is always shown -- as a singleton if necessary:
>>> Cycle(1, 4, 10)(4, 5)
(1 5 4 10)
>>> Cycle(1, 2)(4)(5)(10)
(1 2)(10)
The array form can be used to instantiate a Permutation so other
properties of the permutation can be investigated:
>>> Perm(Cycle(1, 2)(3, 4).list()).transpositions()
[(1, 2), (3, 4)]
Notes
=====
The underlying structure of the Cycle is a dictionary and although
the __iter__ method has been redefined to give the array form of the
cycle, the underlying dictionary items are still available with the
such methods as items():
>>> list(Cycle(1, 2).items())
[(1, 2), (2, 1)]
See Also
========
Permutation
"""
def __missing__(self, arg):
"""Enter arg into dictionary and return arg."""
return as_int(arg)
def __iter__(self):
yield from self.list()
def __call__(self, *other):
"""Return product of cycles processed from R to L.
Examples
========
>>> from sympy.combinatorics import Cycle
>>> Cycle(1, 2)(2, 3)
(1 3 2)
An instance of a Cycle will automatically parse list-like
objects and Permutations that are on the right. It is more
flexible than the Permutation in that all elements need not
be present:
>>> a = Cycle(1, 2)
>>> a(2, 3)
(1 3 2)
>>> a(2, 3)(4, 5)
(1 3 2)(4 5)
"""
rv = Cycle(*other)
for k, v in zip(list(self.keys()), [rv[self[k]] for k in self.keys()]):
rv[k] = v
return rv
def list(self, size=None):
"""Return the cycles as an explicit list starting from 0 up
to the greater of the largest value in the cycles and size.
Truncation of trailing unmoved items will occur when size
is less than the maximum element in the cycle; if this is
desired, setting ``size=-1`` will guarantee such trimming.
Examples
========
>>> from sympy.combinatorics import Cycle
>>> p = Cycle(2, 3)(4, 5)
>>> p.list()
[0, 1, 3, 2, 5, 4]
>>> p.list(10)
[0, 1, 3, 2, 5, 4, 6, 7, 8, 9]
Passing a length too small will trim trailing, unchanged elements
in the permutation:
>>> Cycle(2, 4)(1, 2, 4).list(-1)
[0, 2, 1]
"""
if not self and size is None:
raise ValueError('must give size for empty Cycle')
if size is not None:
big = max([i for i in self.keys() if self[i] != i] + [0])
size = max(size, big + 1)
else:
size = self.size
return [self[i] for i in range(size)]
def __repr__(self):
"""We want it to print as a Cycle, not as a dict.
Examples
========
>>> from sympy.combinatorics import Cycle
>>> Cycle(1, 2)
(1 2)
>>> print(_)
(1 2)
>>> list(Cycle(1, 2).items())
[(1, 2), (2, 1)]
"""
if not self:
return 'Cycle()'
cycles = Permutation(self).cyclic_form
s = ''.join(str(tuple(c)) for c in cycles)
big = self.size - 1
if not any(i == big for c in cycles for i in c):
s += '(%s)' % big
return 'Cycle%s' % s
def __str__(self):
"""We want it to be printed in a Cycle notation with no
comma in-between.
Examples
========
>>> from sympy.combinatorics import Cycle
>>> Cycle(1, 2)
(1 2)
>>> Cycle(1, 2, 4)(5, 6)
(1 2 4)(5 6)
"""
if not self:
return '()'
cycles = Permutation(self).cyclic_form
s = ''.join(str(tuple(c)) for c in cycles)
big = self.size - 1
if not any(i == big for c in cycles for i in c):
s += '(%s)' % big
s = s.replace(',', '')
return s
def __init__(self, *args):
"""Load up a Cycle instance with the values for the cycle.
Examples
========
>>> from sympy.combinatorics import Cycle
>>> Cycle(1, 2, 6)
(1 2 6)
"""
if not args:
return
if len(args) == 1:
if isinstance(args[0], Permutation):
for c in args[0].cyclic_form:
self.update(self(*c))
return
elif isinstance(args[0], Cycle):
for k, v in args[0].items():
self[k] = v
return
args = [as_int(a) for a in args]
if any(i < 0 for i in args):
raise ValueError('negative integers are not allowed in a cycle.')
if has_dups(args):
raise ValueError('All elements must be unique in a cycle.')
for i in range(-len(args), 0):
self[args[i]] = args[i + 1]
@property
def size(self):
if not self:
return 0
return max(self.keys()) + 1
def copy(self):
return Cycle(self)
class Permutation(Atom):
r"""
A permutation, alternatively known as an 'arrangement number' or 'ordering'
is an arrangement of the elements of an ordered list into a one-to-one
mapping with itself. The permutation of a given arrangement is given by
indicating the positions of the elements after re-arrangement [2]_. For
example, if one started with elements ``[x, y, a, b]`` (in that order) and
they were reordered as ``[x, y, b, a]`` then the permutation would be
``[0, 1, 3, 2]``. Notice that (in SymPy) the first element is always referred
to as 0 and the permutation uses the indices of the elements in the
original ordering, not the elements ``(a, b, ...)`` themselves.
>>> from sympy.combinatorics import Permutation
>>> from sympy import init_printing
>>> init_printing(perm_cyclic=False, pretty_print=False)
Permutations Notation
=====================
Permutations are commonly represented in disjoint cycle or array forms.
Array Notation and 2-line Form
------------------------------------
In the 2-line form, the elements and their final positions are shown
as a matrix with 2 rows:
[0 1 2 ... n-1]
[p(0) p(1) p(2) ... p(n-1)]
Since the first line is always ``range(n)``, where n is the size of p,
it is sufficient to represent the permutation by the second line,
referred to as the "array form" of the permutation. This is entered
in brackets as the argument to the Permutation class:
>>> p = Permutation([0, 2, 1]); p
Permutation([0, 2, 1])
Given i in range(p.size), the permutation maps i to i^p
>>> [i^p for i in range(p.size)]
[0, 2, 1]
The composite of two permutations p*q means first apply p, then q, so
i^(p*q) = (i^p)^q which is i^p^q according to Python precedence rules:
>>> q = Permutation([2, 1, 0])
>>> [i^p^q for i in range(3)]
[2, 0, 1]
>>> [i^(p*q) for i in range(3)]
[2, 0, 1]
One can use also the notation p(i) = i^p, but then the composition
rule is (p*q)(i) = q(p(i)), not p(q(i)):
>>> [(p*q)(i) for i in range(p.size)]
[2, 0, 1]
>>> [q(p(i)) for i in range(p.size)]
[2, 0, 1]
>>> [p(q(i)) for i in range(p.size)]
[1, 2, 0]
Disjoint Cycle Notation
-----------------------
In disjoint cycle notation, only the elements that have shifted are
indicated.
For example, [1, 3, 2, 0] can be represented as (0, 1, 3)(2).
This can be understood from the 2 line format of the given permutation.
In the 2-line form,
[0 1 2 3]
[1 3 2 0]
The element in the 0th position is 1, so 0 -> 1. The element in the 1st
position is three, so 1 -> 3. And the element in the third position is again
0, so 3 -> 0. Thus, 0 -> 1 -> 3 -> 0, and 2 -> 2. Thus, this can be represented
as 2 cycles: (0, 1, 3)(2).
In common notation, singular cycles are not explicitly written as they can be
inferred implicitly.
Only the relative ordering of elements in a cycle matter:
>>> Permutation(1,2,3) == Permutation(2,3,1) == Permutation(3,1,2)
True
The disjoint cycle notation is convenient when representing
permutations that have several cycles in them:
>>> Permutation(1, 2)(3, 5) == Permutation([[1, 2], [3, 5]])
True
It also provides some economy in entry when computing products of
permutations that are written in disjoint cycle notation:
>>> Permutation(1, 2)(1, 3)(2, 3)
Permutation([0, 3, 2, 1])
>>> _ == Permutation([[1, 2]])*Permutation([[1, 3]])*Permutation([[2, 3]])
True
Caution: when the cycles have common elements between them then the order
in which the permutations are applied matters. This module applies
the permutations from *left to right*.
>>> Permutation(1, 2)(2, 3) == Permutation([(1, 2), (2, 3)])
True
>>> Permutation(1, 2)(2, 3).list()
[0, 3, 1, 2]
In the above case, (1,2) is computed before (2,3).
As 0 -> 0, 0 -> 0, element in position 0 is 0.
As 1 -> 2, 2 -> 3, element in position 1 is 3.
As 2 -> 1, 1 -> 1, element in position 2 is 1.
As 3 -> 3, 3 -> 2, element in position 3 is 2.
If the first and second elements had been
swapped first, followed by the swapping of the second
and third, the result would have been [0, 2, 3, 1].
If, you want to apply the cycles in the conventional
right to left order, call the function with arguments in reverse order
as demonstrated below:
>>> Permutation([(1, 2), (2, 3)][::-1]).list()
[0, 2, 3, 1]
Entering a singleton in a permutation is a way to indicate the size of the
permutation. The ``size`` keyword can also be used.
Array-form entry:
>>> Permutation([[1, 2], [9]])
Permutation([0, 2, 1], size=10)
>>> Permutation([[1, 2]], size=10)
Permutation([0, 2, 1], size=10)
Cyclic-form entry:
>>> Permutation(1, 2, size=10)
Permutation([0, 2, 1], size=10)
>>> Permutation(9)(1, 2)
Permutation([0, 2, 1], size=10)
Caution: no singleton containing an element larger than the largest
in any previous cycle can be entered. This is an important difference
in how Permutation and Cycle handle the ``__call__`` syntax. A singleton
argument at the start of a Permutation performs instantiation of the
Permutation and is permitted:
>>> Permutation(5)
Permutation([], size=6)
A singleton entered after instantiation is a call to the permutation
-- a function call -- and if the argument is out of range it will
trigger an error. For this reason, it is better to start the cycle
with the singleton:
The following fails because there is no element 3:
>>> Permutation(1, 2)(3)
Traceback (most recent call last):
...
IndexError: list index out of range
This is ok: only the call to an out of range singleton is prohibited;
otherwise the permutation autosizes:
>>> Permutation(3)(1, 2)
Permutation([0, 2, 1, 3])
>>> Permutation(1, 2)(3, 4) == Permutation(3, 4)(1, 2)
True
Equality testing
----------------
The array forms must be the same in order for permutations to be equal:
>>> Permutation([1, 0, 2, 3]) == Permutation([1, 0])
False
Identity Permutation
--------------------
The identity permutation is a permutation in which no element is out of
place. It can be entered in a variety of ways. All the following create
an identity permutation of size 4:
>>> I = Permutation([0, 1, 2, 3])
>>> all(p == I for p in [
... Permutation(3),
... Permutation(range(4)),
... Permutation([], size=4),
... Permutation(size=4)])
True
Watch out for entering the range *inside* a set of brackets (which is
cycle notation):
>>> I == Permutation([range(4)])
False
Permutation Printing
====================
There are a few things to note about how Permutations are printed.
.. deprecated:: 1.6
Configuring Permutation printing by setting
``Permutation.print_cyclic`` is deprecated. Users should use the
``perm_cyclic`` flag to the printers, as described below.
1) If you prefer one form (array or cycle) over another, you can set
``init_printing`` with the ``perm_cyclic`` flag.
>>> from sympy import init_printing
>>> p = Permutation(1, 2)(4, 5)(3, 4)
>>> p
Permutation([0, 2, 1, 4, 5, 3])
>>> init_printing(perm_cyclic=True, pretty_print=False)
>>> p
(1 2)(3 4 5)
2) Regardless of the setting, a list of elements in the array for cyclic
form can be obtained and either of those can be copied and supplied as
the argument to Permutation:
>>> p.array_form
[0, 2, 1, 4, 5, 3]
>>> p.cyclic_form
[[1, 2], [3, 4, 5]]
>>> Permutation(_) == p
True
3) Printing is economical in that as little as possible is printed while
retaining all information about the size of the permutation:
>>> init_printing(perm_cyclic=False, pretty_print=False)
>>> Permutation([1, 0, 2, 3])
Permutation([1, 0, 2, 3])
>>> Permutation([1, 0, 2, 3], size=20)
Permutation([1, 0], size=20)
>>> Permutation([1, 0, 2, 4, 3, 5, 6], size=20)
Permutation([1, 0, 2, 4, 3], size=20)
>>> p = Permutation([1, 0, 2, 3])
>>> init_printing(perm_cyclic=True, pretty_print=False)
>>> p
(3)(0 1)
>>> init_printing(perm_cyclic=False, pretty_print=False)
The 2 was not printed but it is still there as can be seen with the
array_form and size methods:
>>> p.array_form
[1, 0, 2, 3]
>>> p.size
4
Short introduction to other methods
===================================
The permutation can act as a bijective function, telling what element is
located at a given position
>>> q = Permutation([5, 2, 3, 4, 1, 0])
>>> q.array_form[1] # the hard way
2
>>> q(1) # the easy way
2
>>> {i: q(i) for i in range(q.size)} # showing the bijection
{0: 5, 1: 2, 2: 3, 3: 4, 4: 1, 5: 0}
The full cyclic form (including singletons) can be obtained:
>>> p.full_cyclic_form
[[0, 1], [2], [3]]
Any permutation can be factored into transpositions of pairs of elements:
>>> Permutation([[1, 2], [3, 4, 5]]).transpositions()
[(1, 2), (3, 5), (3, 4)]
>>> Permutation.rmul(*[Permutation([ti], size=6) for ti in _]).cyclic_form
[[1, 2], [3, 4, 5]]
The number of permutations on a set of n elements is given by n! and is
called the cardinality.
>>> p.size
4
>>> p.cardinality
24
A given permutation has a rank among all the possible permutations of the
same elements, but what that rank is depends on how the permutations are
enumerated. (There are a number of different methods of doing so.) The
lexicographic rank is given by the rank method and this rank is used to
increment a permutation with addition/subtraction:
>>> p.rank()
6
>>> p + 1
Permutation([1, 0, 3, 2])
>>> p.next_lex()
Permutation([1, 0, 3, 2])
>>> _.rank()
7
>>> p.unrank_lex(p.size, rank=7)
Permutation([1, 0, 3, 2])
The product of two permutations p and q is defined as their composition as
functions, (p*q)(i) = q(p(i)) [6]_.
>>> p = Permutation([1, 0, 2, 3])
>>> q = Permutation([2, 3, 1, 0])
>>> list(q*p)
[2, 3, 0, 1]
>>> list(p*q)
[3, 2, 1, 0]
>>> [q(p(i)) for i in range(p.size)]
[3, 2, 1, 0]
The permutation can be 'applied' to any list-like object, not only
Permutations:
>>> p(['zero', 'one', 'four', 'two'])
['one', 'zero', 'four', 'two']
>>> p('zo42')
['o', 'z', '4', '2']
If you have a list of arbitrary elements, the corresponding permutation
can be found with the from_sequence method:
>>> Permutation.from_sequence('SymPy')
Permutation([1, 3, 2, 0, 4])
Checking if a Permutation is contained in a Group
=================================================
Generally if you have a group of permutations G on n symbols, and
you're checking if a permutation on less than n symbols is part
of that group, the check will fail.
Here is an example for n=5 and we check if the cycle
(1,2,3) is in G:
>>> from sympy import init_printing
>>> init_printing(perm_cyclic=True, pretty_print=False)
>>> from sympy.combinatorics import Cycle, Permutation
>>> from sympy.combinatorics.perm_groups import PermutationGroup
>>> G = PermutationGroup(Cycle(2, 3)(4, 5), Cycle(1, 2, 3, 4, 5))
>>> p1 = Permutation(Cycle(2, 5, 3))
>>> p2 = Permutation(Cycle(1, 2, 3))
>>> a1 = Permutation(Cycle(1, 2, 3).list(6))
>>> a2 = Permutation(Cycle(1, 2, 3)(5))
>>> a3 = Permutation(Cycle(1, 2, 3),size=6)
>>> for p in [p1,p2,a1,a2,a3]: p, G.contains(p)
((2 5 3), True)
((1 2 3), False)
((5)(1 2 3), True)
((5)(1 2 3), True)
((5)(1 2 3), True)
The check for p2 above will fail.
Checking if p1 is in G works because SymPy knows
G is a group on 5 symbols, and p1 is also on 5 symbols
(its largest element is 5).
For ``a1``, the ``.list(6)`` call will extend the permutation to 5
symbols, so the test will work as well. In the case of ``a2`` the
permutation is being extended to 5 symbols by using a singleton,
and in the case of ``a3`` it's extended through the constructor
argument ``size=6``.
There is another way to do this, which is to tell the ``contains``
method that the number of symbols the group is on does not need to
match perfectly the number of symbols for the permutation:
>>> G.contains(p2,strict=False)
True
This can be via the ``strict`` argument to the ``contains`` method,
and SymPy will try to extend the permutation on its own and then
perform the containment check.
See Also
========
Cycle
References
==========
.. [1] Skiena, S. 'Permutations.' 1.1 in Implementing Discrete Mathematics
Combinatorics and Graph Theory with Mathematica. Reading, MA:
Addison-Wesley, pp. 3-16, 1990.
.. [2] Knuth, D. E. The Art of Computer Programming, Vol. 4: Combinatorial
Algorithms, 1st ed. Reading, MA: Addison-Wesley, 2011.
.. [3] Wendy Myrvold and Frank Ruskey. 2001. Ranking and unranking
permutations in linear time. Inf. Process. Lett. 79, 6 (September 2001),
281-284. DOI=10.1016/S0020-0190(01)00141-7
.. [4] D. L. Kreher, D. R. Stinson 'Combinatorial Algorithms'
CRC Press, 1999
.. [5] Graham, R. L.; Knuth, D. E.; and Patashnik, O.
Concrete Mathematics: A Foundation for Computer Science, 2nd ed.
Reading, MA: Addison-Wesley, 1994.
.. [6] https://en.wikipedia.org/w/index.php?oldid=499948155#Product_and_inverse
.. [7] https://en.wikipedia.org/wiki/Lehmer_code
"""
is_Permutation = True
_array_form = None
_cyclic_form = None
_cycle_structure = None
_size = None
_rank = None
def __new__(cls, *args, size=None, **kwargs):
"""
Constructor for the Permutation object from a list or a
list of lists in which all elements of the permutation may
appear only once.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> from sympy import init_printing
>>> init_printing(perm_cyclic=False, pretty_print=False)
Permutations entered in array-form are left unaltered:
>>> Permutation([0, 2, 1])
Permutation([0, 2, 1])
Permutations entered in cyclic form are converted to array form;
singletons need not be entered, but can be entered to indicate the
largest element:
>>> Permutation([[4, 5, 6], [0, 1]])
Permutation([1, 0, 2, 3, 5, 6, 4])
>>> Permutation([[4, 5, 6], [0, 1], [19]])
Permutation([1, 0, 2, 3, 5, 6, 4], size=20)
All manipulation of permutations assumes that the smallest element
is 0 (in keeping with 0-based indexing in Python) so if the 0 is
missing when entering a permutation in array form, an error will be
raised:
>>> Permutation([2, 1])
Traceback (most recent call last):
...
ValueError: Integers 0 through 2 must be present.
If a permutation is entered in cyclic form, it can be entered without
singletons and the ``size`` specified so those values can be filled
in, otherwise the array form will only extend to the maximum value
in the cycles:
>>> Permutation([[1, 4], [3, 5, 2]], size=10)
Permutation([0, 4, 3, 5, 1, 2], size=10)
>>> _.array_form
[0, 4, 3, 5, 1, 2, 6, 7, 8, 9]
"""
if size is not None:
size = int(size)
#a) ()
#b) (1) = identity
#c) (1, 2) = cycle
#d) ([1, 2, 3]) = array form
#e) ([[1, 2]]) = cyclic form
#f) (Cycle) = conversion to permutation
#g) (Permutation) = adjust size or return copy
ok = True
if not args: # a
return cls._af_new(list(range(size or 0)))
elif len(args) > 1: # c
return cls._af_new(Cycle(*args).list(size))
if len(args) == 1:
a = args[0]
if isinstance(a, cls): # g
if size is None or size == a.size:
return a
return cls(a.array_form, size=size)
if isinstance(a, Cycle): # f
return cls._af_new(a.list(size))
if not is_sequence(a): # b
if size is not None and a + 1 > size:
raise ValueError('size is too small when max is %s' % a)
return cls._af_new(list(range(a + 1)))
if has_variety(is_sequence(ai) for ai in a):
ok = False
else:
ok = False
if not ok:
raise ValueError("Permutation argument must be a list of ints, "
"a list of lists, Permutation or Cycle.")
# safe to assume args are valid; this also makes a copy
# of the args
args = list(args[0])
is_cycle = args and is_sequence(args[0])
if is_cycle: # e
args = [[int(i) for i in c] for c in args]
else: # d
args = [int(i) for i in args]
# if there are n elements present, 0, 1, ..., n-1 should be present
# unless a cycle notation has been provided. A 0 will be added
# for convenience in case one wants to enter permutations where
# counting starts from 1.
temp = flatten(args)
if has_dups(temp) and not is_cycle:
raise ValueError('there were repeated elements.')
temp = set(temp)
if not is_cycle:
if temp != set(range(len(temp))):
raise ValueError('Integers 0 through %s must be present.' %
max(temp))
if size is not None and temp and max(temp) + 1 > size:
raise ValueError('max element should not exceed %s' % (size - 1))
if is_cycle:
# it's not necessarily canonical so we won't store
# it -- use the array form instead
c = Cycle()
for ci in args:
c = c(*ci)
aform = c.list()
else:
aform = list(args)
if size and size > len(aform):
# don't allow for truncation of permutation which
# might split a cycle and lead to an invalid aform
# but do allow the permutation size to be increased
aform.extend(list(range(len(aform), size)))
return cls._af_new(aform)
@classmethod
def _af_new(cls, perm):
"""A method to produce a Permutation object from a list;
the list is bound to the _array_form attribute, so it must
not be modified; this method is meant for internal use only;
the list ``a`` is supposed to be generated as a temporary value
in a method, so p = Perm._af_new(a) is the only object
to hold a reference to ``a``::
Examples
========
>>> from sympy.combinatorics.permutations import Perm
>>> from sympy import init_printing
>>> init_printing(perm_cyclic=False, pretty_print=False)
>>> a = [2, 1, 3, 0]
>>> p = Perm._af_new(a)
>>> p
Permutation([2, 1, 3, 0])
"""
p = super().__new__(cls)
p._array_form = perm
p._size = len(perm)
return p
def copy(self):
return self.__class__(self.array_form)
def __getnewargs__(self):
return (self.array_form,)
def _hashable_content(self):
# the array_form (a list) is the Permutation arg, so we need to
# return a tuple, instead
return tuple(self.array_form)
@property
def array_form(self):
"""
Return a copy of the attribute _array_form
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation([[2, 0], [3, 1]])
>>> p.array_form
[2, 3, 0, 1]
>>> Permutation([[2, 0, 3, 1]]).array_form
[3, 2, 0, 1]
>>> Permutation([2, 0, 3, 1]).array_form
[2, 0, 3, 1]
>>> Permutation([[1, 2], [4, 5]]).array_form
[0, 2, 1, 3, 5, 4]
"""
return self._array_form[:]
def list(self, size=None):
"""Return the permutation as an explicit list, possibly
trimming unmoved elements if size is less than the maximum
element in the permutation; if this is desired, setting
``size=-1`` will guarantee such trimming.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation(2, 3)(4, 5)
>>> p.list()
[0, 1, 3, 2, 5, 4]
>>> p.list(10)
[0, 1, 3, 2, 5, 4, 6, 7, 8, 9]
Passing a length too small will trim trailing, unchanged elements
in the permutation:
>>> Permutation(2, 4)(1, 2, 4).list(-1)
[0, 2, 1]
>>> Permutation(3).list(-1)
[]
"""
if not self and size is None:
raise ValueError('must give size for empty Cycle')
rv = self.array_form
if size is not None:
if size > self.size:
rv.extend(list(range(self.size, size)))
else:
# find first value from rhs where rv[i] != i
i = self.size - 1
while rv:
if rv[-1] != i:
break
rv.pop()
i -= 1
return rv
@property
def cyclic_form(self):
"""
This is used to convert to the cyclic notation
from the canonical notation. Singletons are omitted.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation([0, 3, 1, 2])
>>> p.cyclic_form
[[1, 3, 2]]
>>> Permutation([1, 0, 2, 4, 3, 5]).cyclic_form
[[0, 1], [3, 4]]
See Also
========
array_form, full_cyclic_form
"""
if self._cyclic_form is not None:
return list(self._cyclic_form)
array_form = self.array_form
unchecked = [True] * len(array_form)
cyclic_form = []
for i in range(len(array_form)):
if unchecked[i]:
cycle = []
cycle.append(i)
unchecked[i] = False
j = i
while unchecked[array_form[j]]:
j = array_form[j]
cycle.append(j)
unchecked[j] = False
if len(cycle) > 1:
cyclic_form.append(cycle)
assert cycle == list(minlex(cycle))
cyclic_form.sort()
self._cyclic_form = cyclic_form[:]
return cyclic_form
@property
def full_cyclic_form(self):
"""Return permutation in cyclic form including singletons.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> Permutation([0, 2, 1]).full_cyclic_form
[[0], [1, 2]]
"""
need = set(range(self.size)) - set(flatten(self.cyclic_form))
rv = self.cyclic_form + [[i] for i in need]
rv.sort()
return rv
@property
def size(self):
"""
Returns the number of elements in the permutation.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> Permutation([[3, 2], [0, 1]]).size
4
See Also
========
cardinality, length, order, rank
"""
return self._size
def support(self):
"""Return the elements in permutation, P, for which P[i] != i.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation([[3, 2], [0, 1], [4]])
>>> p.array_form
[1, 0, 3, 2, 4]
>>> p.support()
[0, 1, 2, 3]
"""
a = self.array_form
return [i for i, e in enumerate(a) if a[i] != i]
def __add__(self, other):
"""Return permutation that is other higher in rank than self.
The rank is the lexicographical rank, with the identity permutation
having rank of 0.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> I = Permutation([0, 1, 2, 3])
>>> a = Permutation([2, 1, 3, 0])
>>> I + a.rank() == a
True
See Also
========
__sub__, inversion_vector
"""
rank = (self.rank() + other) % self.cardinality
rv = self.unrank_lex(self.size, rank)
rv._rank = rank
return rv
def __sub__(self, other):
"""Return the permutation that is other lower in rank than self.
See Also
========
__add__
"""
return self.__add__(-other)
@staticmethod
def rmul(*args):
"""
Return product of Permutations [a, b, c, ...] as the Permutation whose
ith value is a(b(c(i))).
a, b, c, ... can be Permutation objects or tuples.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> a, b = [1, 0, 2], [0, 2, 1]
>>> a = Permutation(a); b = Permutation(b)
>>> list(Permutation.rmul(a, b))
[1, 2, 0]
>>> [a(b(i)) for i in range(3)]
[1, 2, 0]
This handles the operands in reverse order compared to the ``*`` operator:
>>> a = Permutation(a); b = Permutation(b)
>>> list(a*b)
[2, 0, 1]
>>> [b(a(i)) for i in range(3)]
[2, 0, 1]
Notes
=====
All items in the sequence will be parsed by Permutation as
necessary as long as the first item is a Permutation:
>>> Permutation.rmul(a, [0, 2, 1]) == Permutation.rmul(a, b)
True
The reverse order of arguments will raise a TypeError.
"""
rv = args[0]
for i in range(1, len(args)):
rv = args[i]*rv
return rv
@classmethod
def rmul_with_af(cls, *args):
"""
same as rmul, but the elements of args are Permutation objects
which have _array_form
"""
a = [x._array_form for x in args]
rv = cls._af_new(_af_rmuln(*a))
return rv
def mul_inv(self, other):
"""
other*~self, self and other have _array_form
"""
a = _af_invert(self._array_form)
b = other._array_form
return self._af_new(_af_rmul(a, b))
def __rmul__(self, other):
"""This is needed to coerce other to Permutation in rmul."""
cls = type(self)
return cls(other)*self
def __mul__(self, other):
"""
Return the product a*b as a Permutation; the ith value is b(a(i)).
Examples
========
>>> from sympy.combinatorics.permutations import _af_rmul, Permutation
>>> a, b = [1, 0, 2], [0, 2, 1]
>>> a = Permutation(a); b = Permutation(b)
>>> list(a*b)
[2, 0, 1]
>>> [b(a(i)) for i in range(3)]
[2, 0, 1]
This handles operands in reverse order compared to _af_rmul and rmul:
>>> al = list(a); bl = list(b)
>>> _af_rmul(al, bl)
[1, 2, 0]
>>> [al[bl[i]] for i in range(3)]
[1, 2, 0]
It is acceptable for the arrays to have different lengths; the shorter
one will be padded to match the longer one:
>>> from sympy import init_printing
>>> init_printing(perm_cyclic=False, pretty_print=False)
>>> b*Permutation([1, 0])
Permutation([1, 2, 0])
>>> Permutation([1, 0])*b
Permutation([2, 0, 1])
It is also acceptable to allow coercion to handle conversion of a
single list to the left of a Permutation:
>>> [0, 1]*a # no change: 2-element identity
Permutation([1, 0, 2])
>>> [[0, 1]]*a # exchange first two elements
Permutation([0, 1, 2])
You cannot use more than 1 cycle notation in a product of cycles
since coercion can only handle one argument to the left. To handle
multiple cycles it is convenient to use Cycle instead of Permutation:
>>> [[1, 2]]*[[2, 3]]*Permutation([]) # doctest: +SKIP
>>> from sympy.combinatorics.permutations import Cycle
>>> Cycle(1, 2)(2, 3)
(1 3 2)
"""
from sympy.combinatorics.perm_groups import PermutationGroup, Coset
if isinstance(other, PermutationGroup):
return Coset(self, other, dir='-')
a = self.array_form
# __rmul__ makes sure the other is a Permutation
b = other.array_form
if not b:
perm = a
else:
b.extend(list(range(len(b), len(a))))
perm = [b[i] for i in a] + b[len(a):]
return self._af_new(perm)
def commutes_with(self, other):
"""
Checks if the elements are commuting.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> a = Permutation([1, 4, 3, 0, 2, 5])
>>> b = Permutation([0, 1, 2, 3, 4, 5])
>>> a.commutes_with(b)
True
>>> b = Permutation([2, 3, 5, 4, 1, 0])
>>> a.commutes_with(b)
False
"""
a = self.array_form
b = other.array_form
return _af_commutes_with(a, b)
def __pow__(self, n):
"""
Routine for finding powers of a permutation.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> from sympy import init_printing
>>> init_printing(perm_cyclic=False, pretty_print=False)
>>> p = Permutation([2, 0, 3, 1])
>>> p.order()
4
>>> p**4
Permutation([0, 1, 2, 3])
"""
if isinstance(n, Permutation):
raise NotImplementedError(
'p**p is not defined; do you mean p^p (conjugate)?')
n = int(n)
return self._af_new(_af_pow(self.array_form, n))
def __rxor__(self, i):
"""Return self(i) when ``i`` is an int.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation(1, 2, 9)
>>> 2^p == p(2) == 9
True
"""
if int_valued(i):
return self(i)
else:
raise NotImplementedError(
"i^p = p(i) when i is an integer, not %s." % i)
def __xor__(self, h):
"""Return the conjugate permutation ``~h*self*h` `.
Explanation
===========
If ``a`` and ``b`` are conjugates, ``a = h*b*~h`` and
``b = ~h*a*h`` and both have the same cycle structure.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation(1, 2, 9)
>>> q = Permutation(6, 9, 8)
>>> p*q != q*p
True
Calculate and check properties of the conjugate:
>>> c = p^q
>>> c == ~q*p*q and p == q*c*~q
True
The expression q^p^r is equivalent to q^(p*r):
>>> r = Permutation(9)(4, 6, 8)
>>> q^p^r == q^(p*r)
True
If the term to the left of the conjugate operator, i, is an integer
then this is interpreted as selecting the ith element from the
permutation to the right:
>>> all(i^p == p(i) for i in range(p.size))
True
Note that the * operator as higher precedence than the ^ operator:
>>> q^r*p^r == q^(r*p)^r == Permutation(9)(1, 6, 4)
True
Notes
=====
In Python the precedence rule is p^q^r = (p^q)^r which differs
in general from p^(q^r)
>>> q^p^r
(9)(1 4 8)
>>> q^(p^r)
(9)(1 8 6)
For a given r and p, both of the following are conjugates of p:
~r*p*r and r*p*~r. But these are not necessarily the same:
>>> ~r*p*r == r*p*~r
True
>>> p = Permutation(1, 2, 9)(5, 6)
>>> ~r*p*r == r*p*~r
False
The conjugate ~r*p*r was chosen so that ``p^q^r`` would be equivalent
to ``p^(q*r)`` rather than ``p^(r*q)``. To obtain r*p*~r, pass ~r to
this method:
>>> p^~r == r*p*~r
True
"""
if self.size != h.size:
raise ValueError("The permutations must be of equal size.")
a = [None]*self.size
h = h._array_form
p = self._array_form
for i in range(self.size):
a[h[i]] = h[p[i]]
return self._af_new(a)
def transpositions(self):
"""
Return the permutation decomposed into a list of transpositions.
Explanation
===========
It is always possible to express a permutation as the product of
transpositions, see [1]
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation([[1, 2, 3], [0, 4, 5, 6, 7]])
>>> t = p.transpositions()
>>> t
[(0, 7), (0, 6), (0, 5), (0, 4), (1, 3), (1, 2)]
>>> print(''.join(str(c) for c in t))
(0, 7)(0, 6)(0, 5)(0, 4)(1, 3)(1, 2)
>>> Permutation.rmul(*[Permutation([ti], size=p.size) for ti in t]) == p
True
References
==========
.. [1] https://en.wikipedia.org/wiki/Transposition_%28mathematics%29#Properties
"""
a = self.cyclic_form
res = []
for x in a:
nx = len(x)
if nx == 2:
res.append(tuple(x))
elif nx > 2:
first = x[0]
for y in x[nx - 1:0:-1]:
res.append((first, y))
return res
@classmethod
def from_sequence(self, i, key=None):
"""Return the permutation needed to obtain ``i`` from the sorted
elements of ``i``. If custom sorting is desired, a key can be given.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> Permutation.from_sequence('SymPy')
(4)(0 1 3)
>>> _(sorted("SymPy"))
['S', 'y', 'm', 'P', 'y']
>>> Permutation.from_sequence('SymPy', key=lambda x: x.lower())
(4)(0 2)(1 3)
"""
ic = list(zip(i, list(range(len(i)))))
if key:
ic.sort(key=lambda x: key(x[0]))
else:
ic.sort()
return ~Permutation([i[1] for i in ic])
def __invert__(self):
"""
Return the inverse of the permutation.
A permutation multiplied by its inverse is the identity permutation.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> from sympy import init_printing
>>> init_printing(perm_cyclic=False, pretty_print=False)
>>> p = Permutation([[2, 0], [3, 1]])
>>> ~p
Permutation([2, 3, 0, 1])
>>> _ == p**-1
True
>>> p*~p == ~p*p == Permutation([0, 1, 2, 3])
True
"""
return self._af_new(_af_invert(self._array_form))
def __iter__(self):
"""Yield elements from array form.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> list(Permutation(range(3)))
[0, 1, 2]
"""
yield from self.array_form
def __repr__(self):
return srepr(self)
def __call__(self, *i):
"""
Allows applying a permutation instance as a bijective function.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation([[2, 0], [3, 1]])
>>> p.array_form
[2, 3, 0, 1]
>>> [p(i) for i in range(4)]
[2, 3, 0, 1]
If an array is given then the permutation selects the items
from the array (i.e. the permutation is applied to the array):
>>> from sympy.abc import x
>>> p([x, 1, 0, x**2])
[0, x**2, x, 1]
"""
# list indices can be Integer or int; leave this
# as it is (don't test or convert it) because this
# gets called a lot and should be fast
if len(i) == 1:
i = i[0]
if not isinstance(i, Iterable):
i = as_int(i)
if i < 0 or i > self.size:
raise TypeError(
"{} should be an integer between 0 and {}"
.format(i, self.size-1))
return self._array_form[i]
# P([a, b, c])
if len(i) != self.size:
raise TypeError(
"{} should have the length {}.".format(i, self.size))
return [i[j] for j in self._array_form]
# P(1, 2, 3)
return self*Permutation(Cycle(*i), size=self.size)
def atoms(self):
"""
Returns all the elements of a permutation
Examples
========
>>> from sympy.combinatorics import Permutation
>>> Permutation([0, 1, 2, 3, 4, 5]).atoms()
{0, 1, 2, 3, 4, 5}
>>> Permutation([[0, 1], [2, 3], [4, 5]]).atoms()
{0, 1, 2, 3, 4, 5}
"""
return set(self.array_form)
def apply(self, i):
r"""Apply the permutation to an expression.
Parameters
==========
i : Expr
It should be an integer between $0$ and $n-1$ where $n$
is the size of the permutation.
If it is a symbol or a symbolic expression that can
have integer values, an ``AppliedPermutation`` object
will be returned which can represent an unevaluated
function.
Notes
=====
Any permutation can be defined as a bijective function
$\sigma : \{ 0, 1, \dots, n-1 \} \rightarrow \{ 0, 1, \dots, n-1 \}$
where $n$ denotes the size of the permutation.
The definition may even be extended for any set with distinctive
elements, such that the permutation can even be applied for
real numbers or such, however, it is not implemented for now for
computational reasons and the integrity with the group theory
module.
This function is similar to the ``__call__`` magic, however,
``__call__`` magic already has some other applications like
permuting an array or attaching new cycles, which would
not always be mathematically consistent.
This also guarantees that the return type is a SymPy integer,
which guarantees the safety to use assumptions.
"""
i = _sympify(i)
if i.is_integer is False:
raise NotImplementedError("{} should be an integer.".format(i))
n = self.size
if (i < 0) == True or (i >= n) == True:
raise NotImplementedError(
"{} should be an integer between 0 and {}".format(i, n-1))
if i.is_Integer:
return Integer(self._array_form[i])
return AppliedPermutation(self, i)
def next_lex(self):
"""
Returns the next permutation in lexicographical order.
If self is the last permutation in lexicographical order
it returns None.
See [4] section 2.4.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation([2, 3, 1, 0])
>>> p = Permutation([2, 3, 1, 0]); p.rank()
17
>>> p = p.next_lex(); p.rank()
18
See Also
========
rank, unrank_lex
"""
perm = self.array_form[:]
n = len(perm)
i = n - 2
while perm[i + 1] < perm[i]:
i -= 1
if i == -1:
return None
else:
j = n - 1
while perm[j] < perm[i]:
j -= 1
perm[j], perm[i] = perm[i], perm[j]
i += 1
j = n - 1
while i < j:
perm[j], perm[i] = perm[i], perm[j]
i += 1
j -= 1
return self._af_new(perm)
@classmethod
def unrank_nonlex(self, n, r):
"""
This is a linear time unranking algorithm that does not
respect lexicographic order [3].
Examples
========
>>> from sympy.combinatorics import Permutation
>>> from sympy import init_printing
>>> init_printing(perm_cyclic=False, pretty_print=False)
>>> Permutation.unrank_nonlex(4, 5)
Permutation([2, 0, 3, 1])
>>> Permutation.unrank_nonlex(4, -1)
Permutation([0, 1, 2, 3])
See Also
========
next_nonlex, rank_nonlex
"""
def _unrank1(n, r, a):
if n > 0:
a[n - 1], a[r % n] = a[r % n], a[n - 1]
_unrank1(n - 1, r//n, a)
id_perm = list(range(n))
n = int(n)
r = r % ifac(n)
_unrank1(n, r, id_perm)
return self._af_new(id_perm)
def rank_nonlex(self, inv_perm=None):
"""
This is a linear time ranking algorithm that does not
enforce lexicographic order [3].
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation([0, 1, 2, 3])
>>> p.rank_nonlex()
23
See Also
========
next_nonlex, unrank_nonlex
"""
def _rank1(n, perm, inv_perm):
if n == 1:
return 0
s = perm[n - 1]
t = inv_perm[n - 1]
perm[n - 1], perm[t] = perm[t], s
inv_perm[n - 1], inv_perm[s] = inv_perm[s], t
return s + n*_rank1(n - 1, perm, inv_perm)
if inv_perm is None:
inv_perm = (~self).array_form
if not inv_perm:
return 0
perm = self.array_form[:]
r = _rank1(len(perm), perm, inv_perm)
return r
def next_nonlex(self):
"""
Returns the next permutation in nonlex order [3].
If self is the last permutation in this order it returns None.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> from sympy import init_printing
>>> init_printing(perm_cyclic=False, pretty_print=False)
>>> p = Permutation([2, 0, 3, 1]); p.rank_nonlex()
5
>>> p = p.next_nonlex(); p
Permutation([3, 0, 1, 2])
>>> p.rank_nonlex()
6
See Also
========
rank_nonlex, unrank_nonlex
"""
r = self.rank_nonlex()
if r == ifac(self.size) - 1:
return None
return self.unrank_nonlex(self.size, r + 1)
def rank(self):
"""
Returns the lexicographic rank of the permutation.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation([0, 1, 2, 3])
>>> p.rank()
0
>>> p = Permutation([3, 2, 1, 0])
>>> p.rank()
23
See Also
========
next_lex, unrank_lex, cardinality, length, order, size
"""
if self._rank is not None:
return self._rank
rank = 0
rho = self.array_form[:]
n = self.size - 1
size = n + 1
psize = int(ifac(n))
for j in range(size - 1):
rank += rho[j]*psize
for i in range(j + 1, size):
if rho[i] > rho[j]:
rho[i] -= 1
psize //= n
n -= 1
self._rank = rank
return rank
@property
def cardinality(self):
"""
Returns the number of all possible permutations.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation([0, 1, 2, 3])
>>> p.cardinality
24
See Also
========
length, order, rank, size
"""
return int(ifac(self.size))
def parity(self):
"""
Computes the parity of a permutation.
Explanation
===========
The parity of a permutation reflects the parity of the
number of inversions in the permutation, i.e., the
number of pairs of x and y such that ``x > y`` but ``p[x] < p[y]``.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation([0, 1, 2, 3])
>>> p.parity()
0
>>> p = Permutation([3, 2, 0, 1])
>>> p.parity()
1
See Also
========
_af_parity
"""
if self._cyclic_form is not None:
return (self.size - self.cycles) % 2
return _af_parity(self.array_form)
@property
def is_even(self):
"""
Checks if a permutation is even.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation([0, 1, 2, 3])
>>> p.is_even
True
>>> p = Permutation([3, 2, 1, 0])
>>> p.is_even
True
See Also
========
is_odd
"""
return not self.is_odd
@property
def is_odd(self):
"""
Checks if a permutation is odd.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation([0, 1, 2, 3])
>>> p.is_odd
False
>>> p = Permutation([3, 2, 0, 1])
>>> p.is_odd
True
See Also
========
is_even
"""
return bool(self.parity() % 2)
@property
def is_Singleton(self):
"""
Checks to see if the permutation contains only one number and is
thus the only possible permutation of this set of numbers
Examples
========
>>> from sympy.combinatorics import Permutation
>>> Permutation([0]).is_Singleton
True
>>> Permutation([0, 1]).is_Singleton
False
See Also
========
is_Empty
"""
return self.size == 1
@property
def is_Empty(self):
"""
Checks to see if the permutation is a set with zero elements
Examples
========
>>> from sympy.combinatorics import Permutation
>>> Permutation([]).is_Empty
True
>>> Permutation([0]).is_Empty
False
See Also
========
is_Singleton
"""
return self.size == 0
@property
def is_identity(self):
return self.is_Identity
@property
def is_Identity(self):
"""
Returns True if the Permutation is an identity permutation.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation([])
>>> p.is_Identity
True
>>> p = Permutation([[0], [1], [2]])
>>> p.is_Identity
True
>>> p = Permutation([0, 1, 2])
>>> p.is_Identity
True
>>> p = Permutation([0, 2, 1])
>>> p.is_Identity
False
See Also
========
order
"""
af = self.array_form
return not af or all(i == af[i] for i in range(self.size))
def ascents(self):
"""
Returns the positions of ascents in a permutation, ie, the location
where p[i] < p[i+1]
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation([4, 0, 1, 3, 2])
>>> p.ascents()
[1, 2]
See Also
========
descents, inversions, min, max
"""
a = self.array_form
pos = [i for i in range(len(a) - 1) if a[i] < a[i + 1]]
return pos
def descents(self):
"""
Returns the positions of descents in a permutation, ie, the location
where p[i] > p[i+1]
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation([4, 0, 1, 3, 2])
>>> p.descents()
[0, 3]
See Also
========
ascents, inversions, min, max
"""
a = self.array_form
pos = [i for i in range(len(a) - 1) if a[i] > a[i + 1]]
return pos
def max(self) -> int:
"""
The maximum element moved by the permutation.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation([1, 0, 2, 3, 4])
>>> p.max()
1
See Also
========
min, descents, ascents, inversions
"""
a = self.array_form
if not a:
return 0
return max(_a for i, _a in enumerate(a) if _a != i)
def min(self) -> int:
"""
The minimum element moved by the permutation.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation([0, 1, 4, 3, 2])
>>> p.min()
2
See Also
========
max, descents, ascents, inversions
"""
a = self.array_form
if not a:
return 0
return min(_a for i, _a in enumerate(a) if _a != i)
def inversions(self):
"""
Computes the number of inversions of a permutation.
Explanation
===========
An inversion is where i > j but p[i] < p[j].
For small length of p, it iterates over all i and j
values and calculates the number of inversions.
For large length of p, it uses a variation of merge
sort to calculate the number of inversions.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation([0, 1, 2, 3, 4, 5])
>>> p.inversions()
0
>>> Permutation([3, 2, 1, 0]).inversions()
6
See Also
========
descents, ascents, min, max
References
==========
.. [1] https://www.cp.eng.chula.ac.th/~prabhas//teaching/algo/algo2008/count-inv.htm
"""
inversions = 0
a = self.array_form
n = len(a)
if n < 130:
for i in range(n - 1):
b = a[i]
for c in a[i + 1:]:
if b > c:
inversions += 1
else:
k = 1
right = 0
arr = a[:]
temp = a[:]
while k < n:
i = 0
while i + k < n:
right = i + k * 2 - 1
if right >= n:
right = n - 1
inversions += _merge(arr, temp, i, i + k, right)
i = i + k * 2
k = k * 2
return inversions
def commutator(self, x):
"""Return the commutator of ``self`` and ``x``: ``~x*~self*x*self``
If f and g are part of a group, G, then the commutator of f and g
is the group identity iff f and g commute, i.e. fg == gf.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> from sympy import init_printing
>>> init_printing(perm_cyclic=False, pretty_print=False)
>>> p = Permutation([0, 2, 3, 1])
>>> x = Permutation([2, 0, 3, 1])
>>> c = p.commutator(x); c
Permutation([2, 1, 3, 0])
>>> c == ~x*~p*x*p
True
>>> I = Permutation(3)
>>> p = [I + i for i in range(6)]
>>> for i in range(len(p)):
... for j in range(len(p)):
... c = p[i].commutator(p[j])
... if p[i]*p[j] == p[j]*p[i]:
... assert c == I
... else:
... assert c != I
...
References
==========
.. [1] https://en.wikipedia.org/wiki/Commutator
"""
a = self.array_form
b = x.array_form
n = len(a)
if len(b) != n:
raise ValueError("The permutations must be of equal size.")
inva = [None]*n
for i in range(n):
inva[a[i]] = i
invb = [None]*n
for i in range(n):
invb[b[i]] = i
return self._af_new([a[b[inva[i]]] for i in invb])
def signature(self):
"""
Gives the signature of the permutation needed to place the
elements of the permutation in canonical order.
The signature is calculated as (-1)^<number of inversions>
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation([0, 1, 2])
>>> p.inversions()
0
>>> p.signature()
1
>>> q = Permutation([0,2,1])
>>> q.inversions()
1
>>> q.signature()
-1
See Also
========
inversions
"""
if self.is_even:
return 1
return -1
def order(self):
"""
Computes the order of a permutation.
When the permutation is raised to the power of its
order it equals the identity permutation.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> from sympy import init_printing
>>> init_printing(perm_cyclic=False, pretty_print=False)
>>> p = Permutation([3, 1, 5, 2, 4, 0])
>>> p.order()
4
>>> (p**(p.order()))
Permutation([], size=6)
See Also
========
identity, cardinality, length, rank, size
"""
return reduce(lcm, [len(cycle) for cycle in self.cyclic_form], 1)
def length(self):
"""
Returns the number of integers moved by a permutation.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> Permutation([0, 3, 2, 1]).length()
2
>>> Permutation([[0, 1], [2, 3]]).length()
4
See Also
========
min, max, support, cardinality, order, rank, size
"""
return len(self.support())
@property
def cycle_structure(self):
"""Return the cycle structure of the permutation as a dictionary
indicating the multiplicity of each cycle length.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> Permutation(3).cycle_structure
{1: 4}
>>> Permutation(0, 4, 3)(1, 2)(5, 6).cycle_structure
{2: 2, 3: 1}
"""
if self._cycle_structure:
rv = self._cycle_structure
else:
rv = defaultdict(int)
singletons = self.size
for c in self.cyclic_form:
rv[len(c)] += 1
singletons -= len(c)
if singletons:
rv[1] = singletons
self._cycle_structure = rv
return dict(rv) # make a copy
@property
def cycles(self):
"""
Returns the number of cycles contained in the permutation
(including singletons).
Examples
========
>>> from sympy.combinatorics import Permutation
>>> Permutation([0, 1, 2]).cycles
3
>>> Permutation([0, 1, 2]).full_cyclic_form
[[0], [1], [2]]
>>> Permutation(0, 1)(2, 3).cycles
2
See Also
========
sympy.functions.combinatorial.numbers.stirling
"""
return len(self.full_cyclic_form)
def index(self):
"""
Returns the index of a permutation.
The index of a permutation is the sum of all subscripts j such
that p[j] is greater than p[j+1].
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation([3, 0, 2, 1, 4])
>>> p.index()
2
"""
a = self.array_form
return sum(j for j in range(len(a) - 1) if a[j] > a[j + 1])
def runs(self):
"""
Returns the runs of a permutation.
An ascending sequence in a permutation is called a run [5].
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation([2, 5, 7, 3, 6, 0, 1, 4, 8])
>>> p.runs()
[[2, 5, 7], [3, 6], [0, 1, 4, 8]]
>>> q = Permutation([1,3,2,0])
>>> q.runs()
[[1, 3], [2], [0]]
"""
return runs(self.array_form)
def inversion_vector(self):
"""Return the inversion vector of the permutation.
The inversion vector consists of elements whose value
indicates the number of elements in the permutation
that are lesser than it and lie on its right hand side.
The inversion vector is the same as the Lehmer encoding of a
permutation.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation([4, 8, 0, 7, 1, 5, 3, 6, 2])
>>> p.inversion_vector()
[4, 7, 0, 5, 0, 2, 1, 1]
>>> p = Permutation([3, 2, 1, 0])
>>> p.inversion_vector()
[3, 2, 1]
The inversion vector increases lexicographically with the rank
of the permutation, the -ith element cycling through 0..i.
>>> p = Permutation(2)
>>> while p:
... print('%s %s %s' % (p, p.inversion_vector(), p.rank()))
... p = p.next_lex()
(2) [0, 0] 0
(1 2) [0, 1] 1
(2)(0 1) [1, 0] 2
(0 1 2) [1, 1] 3
(0 2 1) [2, 0] 4
(0 2) [2, 1] 5
See Also
========
from_inversion_vector
"""
self_array_form = self.array_form
n = len(self_array_form)
inversion_vector = [0] * (n - 1)
for i in range(n - 1):
val = 0
for j in range(i + 1, n):
if self_array_form[j] < self_array_form[i]:
val += 1
inversion_vector[i] = val
return inversion_vector
def rank_trotterjohnson(self):
"""
Returns the Trotter Johnson rank, which we get from the minimal
change algorithm. See [4] section 2.4.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation([0, 1, 2, 3])
>>> p.rank_trotterjohnson()
0
>>> p = Permutation([0, 2, 1, 3])
>>> p.rank_trotterjohnson()
7
See Also
========
unrank_trotterjohnson, next_trotterjohnson
"""
if self.array_form == [] or self.is_Identity:
return 0
if self.array_form == [1, 0]:
return 1
perm = self.array_form
n = self.size
rank = 0
for j in range(1, n):
k = 1
i = 0
while perm[i] != j:
if perm[i] < j:
k += 1
i += 1
j1 = j + 1
if rank % 2 == 0:
rank = j1*rank + j1 - k
else:
rank = j1*rank + k - 1
return rank
@classmethod
def unrank_trotterjohnson(cls, size, rank):
"""
Trotter Johnson permutation unranking. See [4] section 2.4.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> from sympy import init_printing
>>> init_printing(perm_cyclic=False, pretty_print=False)
>>> Permutation.unrank_trotterjohnson(5, 10)
Permutation([0, 3, 1, 2, 4])
See Also
========
rank_trotterjohnson, next_trotterjohnson
"""
perm = [0]*size
r2 = 0
n = ifac(size)
pj = 1
for j in range(2, size + 1):
pj *= j
r1 = (rank * pj) // n
k = r1 - j*r2
if r2 % 2 == 0:
for i in range(j - 1, j - k - 1, -1):
perm[i] = perm[i - 1]
perm[j - k - 1] = j - 1
else:
for i in range(j - 1, k, -1):
perm[i] = perm[i - 1]
perm[k] = j - 1
r2 = r1
return cls._af_new(perm)
def next_trotterjohnson(self):
"""
Returns the next permutation in Trotter-Johnson order.
If self is the last permutation it returns None.
See [4] section 2.4. If it is desired to generate all such
permutations, they can be generated in order more quickly
with the ``generate_bell`` function.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> from sympy import init_printing
>>> init_printing(perm_cyclic=False, pretty_print=False)
>>> p = Permutation([3, 0, 2, 1])
>>> p.rank_trotterjohnson()
4
>>> p = p.next_trotterjohnson(); p
Permutation([0, 3, 2, 1])
>>> p.rank_trotterjohnson()
5
See Also
========
rank_trotterjohnson, unrank_trotterjohnson, sympy.utilities.iterables.generate_bell
"""
pi = self.array_form[:]
n = len(pi)
st = 0
rho = pi[:]
done = False
m = n-1
while m > 0 and not done:
d = rho.index(m)
for i in range(d, m):
rho[i] = rho[i + 1]
par = _af_parity(rho[:m])
if par == 1:
if d == m:
m -= 1
else:
pi[st + d], pi[st + d + 1] = pi[st + d + 1], pi[st + d]
done = True
else:
if d == 0:
m -= 1
st += 1
else:
pi[st + d], pi[st + d - 1] = pi[st + d - 1], pi[st + d]
done = True
if m == 0:
return None
return self._af_new(pi)
def get_precedence_matrix(self):
"""
Gets the precedence matrix. This is used for computing the
distance between two permutations.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> from sympy import init_printing
>>> init_printing(perm_cyclic=False, pretty_print=False)
>>> p = Permutation.josephus(3, 6, 1)
>>> p
Permutation([2, 5, 3, 1, 4, 0])
>>> p.get_precedence_matrix()
Matrix([
[0, 0, 0, 0, 0, 0],
[1, 0, 0, 0, 1, 0],
[1, 1, 0, 1, 1, 1],
[1, 1, 0, 0, 1, 0],
[1, 0, 0, 0, 0, 0],
[1, 1, 0, 1, 1, 0]])
See Also
========
get_precedence_distance, get_adjacency_matrix, get_adjacency_distance
"""
m = zeros(self.size)
perm = self.array_form
for i in range(m.rows):
for j in range(i + 1, m.cols):
m[perm[i], perm[j]] = 1
return m
def get_precedence_distance(self, other):
"""
Computes the precedence distance between two permutations.
Explanation
===========
Suppose p and p' represent n jobs. The precedence metric
counts the number of times a job j is preceded by job i
in both p and p'. This metric is commutative.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation([2, 0, 4, 3, 1])
>>> q = Permutation([3, 1, 2, 4, 0])
>>> p.get_precedence_distance(q)
7
>>> q.get_precedence_distance(p)
7
See Also
========
get_precedence_matrix, get_adjacency_matrix, get_adjacency_distance
"""
if self.size != other.size:
raise ValueError("The permutations must be of equal size.")
self_prec_mat = self.get_precedence_matrix()
other_prec_mat = other.get_precedence_matrix()
n_prec = 0
for i in range(self.size):
for j in range(self.size):
if i == j:
continue
if self_prec_mat[i, j] * other_prec_mat[i, j] == 1:
n_prec += 1
d = self.size * (self.size - 1)//2 - n_prec
return d
def get_adjacency_matrix(self):
"""
Computes the adjacency matrix of a permutation.
Explanation
===========
If job i is adjacent to job j in a permutation p
then we set m[i, j] = 1 where m is the adjacency
matrix of p.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation.josephus(3, 6, 1)
>>> p.get_adjacency_matrix()
Matrix([
[0, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 1, 0],
[0, 0, 0, 0, 0, 1],
[0, 1, 0, 0, 0, 0],
[1, 0, 0, 0, 0, 0],
[0, 0, 0, 1, 0, 0]])
>>> q = Permutation([0, 1, 2, 3])
>>> q.get_adjacency_matrix()
Matrix([
[0, 1, 0, 0],
[0, 0, 1, 0],
[0, 0, 0, 1],
[0, 0, 0, 0]])
See Also
========
get_precedence_matrix, get_precedence_distance, get_adjacency_distance
"""
m = zeros(self.size)
perm = self.array_form
for i in range(self.size - 1):
m[perm[i], perm[i + 1]] = 1
return m
def get_adjacency_distance(self, other):
"""
Computes the adjacency distance between two permutations.
Explanation
===========
This metric counts the number of times a pair i,j of jobs is
adjacent in both p and p'. If n_adj is this quantity then
the adjacency distance is n - n_adj - 1 [1]
[1] Reeves, Colin R. Landscapes, Operators and Heuristic search, Annals
of Operational Research, 86, pp 473-490. (1999)
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation([0, 3, 1, 2, 4])
>>> q = Permutation.josephus(4, 5, 2)
>>> p.get_adjacency_distance(q)
3
>>> r = Permutation([0, 2, 1, 4, 3])
>>> p.get_adjacency_distance(r)
4
See Also
========
get_precedence_matrix, get_precedence_distance, get_adjacency_matrix
"""
if self.size != other.size:
raise ValueError("The permutations must be of the same size.")
self_adj_mat = self.get_adjacency_matrix()
other_adj_mat = other.get_adjacency_matrix()
n_adj = 0
for i in range(self.size):
for j in range(self.size):
if i == j:
continue
if self_adj_mat[i, j] * other_adj_mat[i, j] == 1:
n_adj += 1
d = self.size - n_adj - 1
return d
def get_positional_distance(self, other):
"""
Computes the positional distance between two permutations.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation([0, 3, 1, 2, 4])
>>> q = Permutation.josephus(4, 5, 2)
>>> r = Permutation([3, 1, 4, 0, 2])
>>> p.get_positional_distance(q)
12
>>> p.get_positional_distance(r)
12
See Also
========
get_precedence_distance, get_adjacency_distance
"""
a = self.array_form
b = other.array_form
if len(a) != len(b):
raise ValueError("The permutations must be of the same size.")
return sum(abs(a[i] - b[i]) for i in range(len(a)))
@classmethod
def josephus(cls, m, n, s=1):
"""Return as a permutation the shuffling of range(n) using the Josephus
scheme in which every m-th item is selected until all have been chosen.
The returned permutation has elements listed by the order in which they
were selected.
The parameter ``s`` stops the selection process when there are ``s``
items remaining and these are selected by continuing the selection,
counting by 1 rather than by ``m``.
Consider selecting every 3rd item from 6 until only 2 remain::
choices chosen
======== ======
012345
01 345 2
01 34 25
01 4 253
0 4 2531
0 25314
253140
Examples
========
>>> from sympy.combinatorics import Permutation
>>> Permutation.josephus(3, 6, 2).array_form
[2, 5, 3, 1, 4, 0]
References
==========
.. [1] https://en.wikipedia.org/wiki/Flavius_Josephus
.. [2] https://en.wikipedia.org/wiki/Josephus_problem
.. [3] https://web.archive.org/web/20171008094331/http://www.wou.edu/~burtonl/josephus.html
"""
from collections import deque
m -= 1
Q = deque(list(range(n)))
perm = []
while len(Q) > max(s, 1):
for dp in range(m):
Q.append(Q.popleft())
perm.append(Q.popleft())
perm.extend(list(Q))
return cls(perm)
@classmethod
def from_inversion_vector(cls, inversion):
"""
Calculates the permutation from the inversion vector.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> from sympy import init_printing
>>> init_printing(perm_cyclic=False, pretty_print=False)
>>> Permutation.from_inversion_vector([3, 2, 1, 0, 0])
Permutation([3, 2, 1, 0, 4, 5])
"""
size = len(inversion)
N = list(range(size + 1))
perm = []
try:
for k in range(size):
val = N[inversion[k]]
perm.append(val)
N.remove(val)
except IndexError:
raise ValueError("The inversion vector is not valid.")
perm.extend(N)
return cls._af_new(perm)
@classmethod
def random(cls, n):
"""
Generates a random permutation of length ``n``.
Uses the underlying Python pseudo-random number generator.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> Permutation.random(2) in (Permutation([1, 0]), Permutation([0, 1]))
True
"""
perm_array = list(range(n))
random.shuffle(perm_array)
return cls._af_new(perm_array)
@classmethod
def unrank_lex(cls, size, rank):
"""
Lexicographic permutation unranking.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> from sympy import init_printing
>>> init_printing(perm_cyclic=False, pretty_print=False)
>>> a = Permutation.unrank_lex(5, 10)
>>> a.rank()
10
>>> a
Permutation([0, 2, 4, 1, 3])
See Also
========
rank, next_lex
"""
perm_array = [0] * size
psize = 1
for i in range(size):
new_psize = psize*(i + 1)
d = (rank % new_psize) // psize
rank -= d*psize
perm_array[size - i - 1] = d
for j in range(size - i, size):
if perm_array[j] > d - 1:
perm_array[j] += 1
psize = new_psize
return cls._af_new(perm_array)
def resize(self, n):
"""Resize the permutation to the new size ``n``.
Parameters
==========
n : int
The new size of the permutation.
Raises
======
ValueError
If the permutation cannot be resized to the given size.
This may only happen when resized to a smaller size than
the original.
Examples
========
>>> from sympy.combinatorics import Permutation
Increasing the size of a permutation:
>>> p = Permutation(0, 1, 2)
>>> p = p.resize(5)
>>> p
(4)(0 1 2)
Decreasing the size of the permutation:
>>> p = p.resize(4)
>>> p
(3)(0 1 2)
If resizing to the specific size breaks the cycles:
>>> p.resize(2)
Traceback (most recent call last):
...
ValueError: The permutation cannot be resized to 2 because the
cycle (0, 1, 2) may break.
"""
aform = self.array_form
l = len(aform)
if n > l:
aform += list(range(l, n))
return Permutation._af_new(aform)
elif n < l:
cyclic_form = self.full_cyclic_form
new_cyclic_form = []
for cycle in cyclic_form:
cycle_min = min(cycle)
cycle_max = max(cycle)
if cycle_min <= n-1:
if cycle_max > n-1:
raise ValueError(
"The permutation cannot be resized to {} "
"because the cycle {} may break."
.format(n, tuple(cycle)))
new_cyclic_form.append(cycle)
return Permutation(new_cyclic_form)
return self
# XXX Deprecated flag
print_cyclic = None
def _merge(arr, temp, left, mid, right):
"""
Merges two sorted arrays and calculates the inversion count.
Helper function for calculating inversions. This method is
for internal use only.
"""
i = k = left
j = mid
inv_count = 0
while i < mid and j <= right:
if arr[i] < arr[j]:
temp[k] = arr[i]
k += 1
i += 1
else:
temp[k] = arr[j]
k += 1
j += 1
inv_count += (mid -i)
while i < mid:
temp[k] = arr[i]
k += 1
i += 1
if j <= right:
k += right - j + 1
j += right - j + 1
arr[left:k + 1] = temp[left:k + 1]
else:
arr[left:right + 1] = temp[left:right + 1]
return inv_count
Perm = Permutation
_af_new = Perm._af_new
class AppliedPermutation(Expr):
"""A permutation applied to a symbolic variable.
Parameters
==========
perm : Permutation
x : Expr
Examples
========
>>> from sympy import Symbol
>>> from sympy.combinatorics import Permutation
Creating a symbolic permutation function application:
>>> x = Symbol('x')
>>> p = Permutation(0, 1, 2)
>>> p.apply(x)
AppliedPermutation((0 1 2), x)
>>> _.subs(x, 1)
2
"""
def __new__(cls, perm, x, evaluate=None):
if evaluate is None:
evaluate = global_parameters.evaluate
perm = _sympify(perm)
x = _sympify(x)
if not isinstance(perm, Permutation):
raise ValueError("{} must be a Permutation instance."
.format(perm))
if evaluate:
if x.is_Integer:
return perm.apply(x)
obj = super().__new__(cls, perm, x)
return obj
@dispatch(Permutation, Permutation)
def _eval_is_eq(lhs, rhs):
if lhs._size != rhs._size:
return None
return lhs._array_form == rhs._array_form
PK ]ZZZ���X� X� ! sympy/combinatorics/polyhedron.pyfrom sympy.combinatorics import Permutation as Perm
from sympy.combinatorics.perm_groups import PermutationGroup
from sympy.core import Basic, Tuple, default_sort_key
from sympy.sets import FiniteSet
from sympy.utilities.iterables import (minlex, unflatten, flatten)
from sympy.utilities.misc import as_int
rmul = Perm.rmul
class Polyhedron(Basic):
"""
Represents the polyhedral symmetry group (PSG).
Explanation
===========
The PSG is one of the symmetry groups of the Platonic solids.
There are three polyhedral groups: the tetrahedral group
of order 12, the octahedral group of order 24, and the
icosahedral group of order 60.
All doctests have been given in the docstring of the
constructor of the object.
References
==========
.. [1] https://mathworld.wolfram.com/PolyhedralGroup.html
"""
_edges = None
def __new__(cls, corners, faces=(), pgroup=()):
"""
The constructor of the Polyhedron group object.
Explanation
===========
It takes up to three parameters: the corners, faces, and
allowed transformations.
The corners/vertices are entered as a list of arbitrary
expressions that are used to identify each vertex.
The faces are entered as a list of tuples of indices; a tuple
of indices identifies the vertices which define the face. They
should be entered in a cw or ccw order; they will be standardized
by reversal and rotation to be give the lowest lexical ordering.
If no faces are given then no edges will be computed.
>>> from sympy.combinatorics.polyhedron import Polyhedron
>>> Polyhedron(list('abc'), [(1, 2, 0)]).faces
{(0, 1, 2)}
>>> Polyhedron(list('abc'), [(1, 0, 2)]).faces
{(0, 1, 2)}
The allowed transformations are entered as allowable permutations
of the vertices for the polyhedron. Instance of Permutations
(as with faces) should refer to the supplied vertices by index.
These permutation are stored as a PermutationGroup.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> from sympy import init_printing
>>> from sympy.abc import w, x, y, z
>>> init_printing(pretty_print=False, perm_cyclic=False)
Here we construct the Polyhedron object for a tetrahedron.
>>> corners = [w, x, y, z]
>>> faces = [(0, 1, 2), (0, 2, 3), (0, 3, 1), (1, 2, 3)]
Next, allowed transformations of the polyhedron must be given. This
is given as permutations of vertices.
Although the vertices of a tetrahedron can be numbered in 24 (4!)
different ways, there are only 12 different orientations for a
physical tetrahedron. The following permutations, applied once or
twice, will generate all 12 of the orientations. (The identity
permutation, Permutation(range(4)), is not included since it does
not change the orientation of the vertices.)
>>> pgroup = [Permutation([[0, 1, 2], [3]]), \
Permutation([[0, 1, 3], [2]]), \
Permutation([[0, 2, 3], [1]]), \
Permutation([[1, 2, 3], [0]]), \
Permutation([[0, 1], [2, 3]]), \
Permutation([[0, 2], [1, 3]]), \
Permutation([[0, 3], [1, 2]])]
The Polyhedron is now constructed and demonstrated:
>>> tetra = Polyhedron(corners, faces, pgroup)
>>> tetra.size
4
>>> tetra.edges
{(0, 1), (0, 2), (0, 3), (1, 2), (1, 3), (2, 3)}
>>> tetra.corners
(w, x, y, z)
It can be rotated with an arbitrary permutation of vertices, e.g.
the following permutation is not in the pgroup:
>>> tetra.rotate(Permutation([0, 1, 3, 2]))
>>> tetra.corners
(w, x, z, y)
An allowed permutation of the vertices can be constructed by
repeatedly applying permutations from the pgroup to the vertices.
Here is a demonstration that applying p and p**2 for every p in
pgroup generates all the orientations of a tetrahedron and no others:
>>> all = ( (w, x, y, z), \
(x, y, w, z), \
(y, w, x, z), \
(w, z, x, y), \
(z, w, y, x), \
(w, y, z, x), \
(y, z, w, x), \
(x, z, y, w), \
(z, y, x, w), \
(y, x, z, w), \
(x, w, z, y), \
(z, x, w, y) )
>>> got = []
>>> for p in (pgroup + [p**2 for p in pgroup]):
... h = Polyhedron(corners)
... h.rotate(p)
... got.append(h.corners)
...
>>> set(got) == set(all)
True
The make_perm method of a PermutationGroup will randomly pick
permutations, multiply them together, and return the permutation that
can be applied to the polyhedron to give the orientation produced
by those individual permutations.
Here, 3 permutations are used:
>>> tetra.pgroup.make_perm(3) # doctest: +SKIP
Permutation([0, 3, 1, 2])
To select the permutations that should be used, supply a list
of indices to the permutations in pgroup in the order they should
be applied:
>>> use = [0, 0, 2]
>>> p002 = tetra.pgroup.make_perm(3, use)
>>> p002
Permutation([1, 0, 3, 2])
Apply them one at a time:
>>> tetra.reset()
>>> for i in use:
... tetra.rotate(pgroup[i])
...
>>> tetra.vertices
(x, w, z, y)
>>> sequentially = tetra.vertices
Apply the composite permutation:
>>> tetra.reset()
>>> tetra.rotate(p002)
>>> tetra.corners
(x, w, z, y)
>>> tetra.corners in all and tetra.corners == sequentially
True
Notes
=====
Defining permutation groups
---------------------------
It is not necessary to enter any permutations, nor is necessary to
enter a complete set of transformations. In fact, for a polyhedron,
all configurations can be constructed from just two permutations.
For example, the orientations of a tetrahedron can be generated from
an axis passing through a vertex and face and another axis passing
through a different vertex or from an axis passing through the
midpoints of two edges opposite of each other.
For simplicity of presentation, consider a square --
not a cube -- with vertices 1, 2, 3, and 4:
1-----2 We could think of axes of rotation being:
| | 1) through the face
| | 2) from midpoint 1-2 to 3-4 or 1-3 to 2-4
3-----4 3) lines 1-4 or 2-3
To determine how to write the permutations, imagine 4 cameras,
one at each corner, labeled A-D:
A B A B
1-----2 1-----3 vertex index:
| | | | 1 0
| | | | 2 1
3-----4 2-----4 3 2
C D C D 4 3
original after rotation
along 1-4
A diagonal and a face axis will be chosen for the "permutation group"
from which any orientation can be constructed.
>>> pgroup = []
Imagine a clockwise rotation when viewing 1-4 from camera A. The new
orientation is (in camera-order): 1, 3, 2, 4 so the permutation is
given using the *indices* of the vertices as:
>>> pgroup.append(Permutation((0, 2, 1, 3)))
Now imagine rotating clockwise when looking down an axis entering the
center of the square as viewed. The new camera-order would be
3, 1, 4, 2 so the permutation is (using indices):
>>> pgroup.append(Permutation((2, 0, 3, 1)))
The square can now be constructed:
** use real-world labels for the vertices, entering them in
camera order
** for the faces we use zero-based indices of the vertices
in *edge-order* as the face is traversed; neither the
direction nor the starting point matter -- the faces are
only used to define edges (if so desired).
>>> square = Polyhedron((1, 2, 3, 4), [(0, 1, 3, 2)], pgroup)
To rotate the square with a single permutation we can do:
>>> square.rotate(square.pgroup[0])
>>> square.corners
(1, 3, 2, 4)
To use more than one permutation (or to use one permutation more
than once) it is more convenient to use the make_perm method:
>>> p011 = square.pgroup.make_perm([0, 1, 1]) # diag flip + 2 rotations
>>> square.reset() # return to initial orientation
>>> square.rotate(p011)
>>> square.corners
(4, 2, 3, 1)
Thinking outside the box
------------------------
Although the Polyhedron object has a direct physical meaning, it
actually has broader application. In the most general sense it is
just a decorated PermutationGroup, allowing one to connect the
permutations to something physical. For example, a Rubik's cube is
not a proper polyhedron, but the Polyhedron class can be used to
represent it in a way that helps to visualize the Rubik's cube.
>>> from sympy import flatten, unflatten, symbols
>>> from sympy.combinatorics import RubikGroup
>>> facelets = flatten([symbols(s+'1:5') for s in 'UFRBLD'])
>>> def show():
... pairs = unflatten(r2.corners, 2)
... print(pairs[::2])
... print(pairs[1::2])
...
>>> r2 = Polyhedron(facelets, pgroup=RubikGroup(2))
>>> show()
[(U1, U2), (F1, F2), (R1, R2), (B1, B2), (L1, L2), (D1, D2)]
[(U3, U4), (F3, F4), (R3, R4), (B3, B4), (L3, L4), (D3, D4)]
>>> r2.rotate(0) # cw rotation of F
>>> show()
[(U1, U2), (F3, F1), (U3, R2), (B1, B2), (L1, D1), (R3, R1)]
[(L4, L2), (F4, F2), (U4, R4), (B3, B4), (L3, D2), (D3, D4)]
Predefined Polyhedra
====================
For convenience, the vertices and faces are defined for the following
standard solids along with a permutation group for transformations.
When the polyhedron is oriented as indicated below, the vertices in
a given horizontal plane are numbered in ccw direction, starting from
the vertex that will give the lowest indices in a given face. (In the
net of the vertices, indices preceded by "-" indicate replication of
the lhs index in the net.)
tetrahedron, tetrahedron_faces
------------------------------
4 vertices (vertex up) net:
0 0-0
1 2 3-1
4 faces:
(0, 1, 2) (0, 2, 3) (0, 3, 1) (1, 2, 3)
cube, cube_faces
----------------
8 vertices (face up) net:
0 1 2 3-0
4 5 6 7-4
6 faces:
(0, 1, 2, 3)
(0, 1, 5, 4) (1, 2, 6, 5) (2, 3, 7, 6) (0, 3, 7, 4)
(4, 5, 6, 7)
octahedron, octahedron_faces
----------------------------
6 vertices (vertex up) net:
0 0 0-0
1 2 3 4-1
5 5 5-5
8 faces:
(0, 1, 2) (0, 2, 3) (0, 3, 4) (0, 1, 4)
(1, 2, 5) (2, 3, 5) (3, 4, 5) (1, 4, 5)
dodecahedron, dodecahedron_faces
--------------------------------
20 vertices (vertex up) net:
0 1 2 3 4 -0
5 6 7 8 9 -5
14 10 11 12 13-14
15 16 17 18 19-15
12 faces:
(0, 1, 2, 3, 4) (0, 1, 6, 10, 5) (1, 2, 7, 11, 6)
(2, 3, 8, 12, 7) (3, 4, 9, 13, 8) (0, 4, 9, 14, 5)
(5, 10, 16, 15, 14) (6, 10, 16, 17, 11) (7, 11, 17, 18, 12)
(8, 12, 18, 19, 13) (9, 13, 19, 15, 14)(15, 16, 17, 18, 19)
icosahedron, icosahedron_faces
------------------------------
12 vertices (face up) net:
0 0 0 0 -0
1 2 3 4 5 -1
6 7 8 9 10 -6
11 11 11 11 -11
20 faces:
(0, 1, 2) (0, 2, 3) (0, 3, 4)
(0, 4, 5) (0, 1, 5) (1, 2, 6)
(2, 3, 7) (3, 4, 8) (4, 5, 9)
(1, 5, 10) (2, 6, 7) (3, 7, 8)
(4, 8, 9) (5, 9, 10) (1, 6, 10)
(6, 7, 11) (7, 8, 11) (8, 9, 11)
(9, 10, 11) (6, 10, 11)
>>> from sympy.combinatorics.polyhedron import cube
>>> cube.edges
{(0, 1), (0, 3), (0, 4), (1, 2), (1, 5), (2, 3), (2, 6), (3, 7), (4, 5), (4, 7), (5, 6), (6, 7)}
If you want to use letters or other names for the corners you
can still use the pre-calculated faces:
>>> corners = list('abcdefgh')
>>> Polyhedron(corners, cube.faces).corners
(a, b, c, d, e, f, g, h)
References
==========
.. [1] www.ocf.berkeley.edu/~wwu/articles/platonicsolids.pdf
"""
faces = [minlex(f, directed=False, key=default_sort_key) for f in faces]
corners, faces, pgroup = args = \
[Tuple(*a) for a in (corners, faces, pgroup)]
obj = Basic.__new__(cls, *args)
obj._corners = tuple(corners) # in order given
obj._faces = FiniteSet(*faces)
if pgroup and pgroup[0].size != len(corners):
raise ValueError("Permutation size unequal to number of corners.")
# use the identity permutation if none are given
obj._pgroup = PermutationGroup(
pgroup or [Perm(range(len(corners)))] )
return obj
@property
def corners(self):
"""
Get the corners of the Polyhedron.
The method ``vertices`` is an alias for ``corners``.
Examples
========
>>> from sympy.combinatorics import Polyhedron
>>> from sympy.abc import a, b, c, d
>>> p = Polyhedron(list('abcd'))
>>> p.corners == p.vertices == (a, b, c, d)
True
See Also
========
array_form, cyclic_form
"""
return self._corners
vertices = corners
@property
def array_form(self):
"""Return the indices of the corners.
The indices are given relative to the original position of corners.
Examples
========
>>> from sympy.combinatorics.polyhedron import tetrahedron
>>> tetrahedron = tetrahedron.copy()
>>> tetrahedron.array_form
[0, 1, 2, 3]
>>> tetrahedron.rotate(0)
>>> tetrahedron.array_form
[0, 2, 3, 1]
>>> tetrahedron.pgroup[0].array_form
[0, 2, 3, 1]
See Also
========
corners, cyclic_form
"""
corners = list(self.args[0])
return [corners.index(c) for c in self.corners]
@property
def cyclic_form(self):
"""Return the indices of the corners in cyclic notation.
The indices are given relative to the original position of corners.
See Also
========
corners, array_form
"""
return Perm._af_new(self.array_form).cyclic_form
@property
def size(self):
"""
Get the number of corners of the Polyhedron.
"""
return len(self._corners)
@property
def faces(self):
"""
Get the faces of the Polyhedron.
"""
return self._faces
@property
def pgroup(self):
"""
Get the permutations of the Polyhedron.
"""
return self._pgroup
@property
def edges(self):
"""
Given the faces of the polyhedra we can get the edges.
Examples
========
>>> from sympy.combinatorics import Polyhedron
>>> from sympy.abc import a, b, c
>>> corners = (a, b, c)
>>> faces = [(0, 1, 2)]
>>> Polyhedron(corners, faces).edges
{(0, 1), (0, 2), (1, 2)}
"""
if self._edges is None:
output = set()
for face in self.faces:
for i in range(len(face)):
edge = tuple(sorted([face[i], face[i - 1]]))
output.add(edge)
self._edges = FiniteSet(*output)
return self._edges
def rotate(self, perm):
"""
Apply a permutation to the polyhedron *in place*. The permutation
may be given as a Permutation instance or an integer indicating
which permutation from pgroup of the Polyhedron should be
applied.
This is an operation that is analogous to rotation about
an axis by a fixed increment.
Notes
=====
When a Permutation is applied, no check is done to see if that
is a valid permutation for the Polyhedron. For example, a cube
could be given a permutation which effectively swaps only 2
vertices. A valid permutation (that rotates the object in a
physical way) will be obtained if one only uses
permutations from the ``pgroup`` of the Polyhedron. On the other
hand, allowing arbitrary rotations (applications of permutations)
gives a way to follow named elements rather than indices since
Polyhedron allows vertices to be named while Permutation works
only with indices.
Examples
========
>>> from sympy.combinatorics import Polyhedron, Permutation
>>> from sympy.combinatorics.polyhedron import cube
>>> cube = cube.copy()
>>> cube.corners
(0, 1, 2, 3, 4, 5, 6, 7)
>>> cube.rotate(0)
>>> cube.corners
(1, 2, 3, 0, 5, 6, 7, 4)
A non-physical "rotation" that is not prohibited by this method:
>>> cube.reset()
>>> cube.rotate(Permutation([[1, 2]], size=8))
>>> cube.corners
(0, 2, 1, 3, 4, 5, 6, 7)
Polyhedron can be used to follow elements of set that are
identified by letters instead of integers:
>>> shadow = h5 = Polyhedron(list('abcde'))
>>> p = Permutation([3, 0, 1, 2, 4])
>>> h5.rotate(p)
>>> h5.corners
(d, a, b, c, e)
>>> _ == shadow.corners
True
>>> copy = h5.copy()
>>> h5.rotate(p)
>>> h5.corners == copy.corners
False
"""
if not isinstance(perm, Perm):
perm = self.pgroup[perm]
# and we know it's valid
else:
if perm.size != self.size:
raise ValueError('Polyhedron and Permutation sizes differ.')
a = perm.array_form
corners = [self.corners[a[i]] for i in range(len(self.corners))]
self._corners = tuple(corners)
def reset(self):
"""Return corners to their original positions.
Examples
========
>>> from sympy.combinatorics.polyhedron import tetrahedron as T
>>> T = T.copy()
>>> T.corners
(0, 1, 2, 3)
>>> T.rotate(0)
>>> T.corners
(0, 2, 3, 1)
>>> T.reset()
>>> T.corners
(0, 1, 2, 3)
"""
self._corners = self.args[0]
def _pgroup_calcs():
"""Return the permutation groups for each of the polyhedra and the face
definitions: tetrahedron, cube, octahedron, dodecahedron, icosahedron,
tetrahedron_faces, cube_faces, octahedron_faces, dodecahedron_faces,
icosahedron_faces
Explanation
===========
(This author did not find and did not know of a better way to do it though
there likely is such a way.)
Although only 2 permutations are needed for a polyhedron in order to
generate all the possible orientations, a group of permutations is
provided instead. A set of permutations is called a "group" if::
a*b = c (for any pair of permutations in the group, a and b, their
product, c, is in the group)
a*(b*c) = (a*b)*c (for any 3 permutations in the group associativity holds)
there is an identity permutation, I, such that I*a = a*I for all elements
in the group
a*b = I (the inverse of each permutation is also in the group)
None of the polyhedron groups defined follow these definitions of a group.
Instead, they are selected to contain those permutations whose powers
alone will construct all orientations of the polyhedron, i.e. for
permutations ``a``, ``b``, etc... in the group, ``a, a**2, ..., a**o_a``,
``b, b**2, ..., b**o_b``, etc... (where ``o_i`` is the order of
permutation ``i``) generate all permutations of the polyhedron instead of
mixed products like ``a*b``, ``a*b**2``, etc....
Note that for a polyhedron with n vertices, the valid permutations of the
vertices exclude those that do not maintain its faces. e.g. the
permutation BCDE of a square's four corners, ABCD, is a valid
permutation while CBDE is not (because this would twist the square).
Examples
========
The is_group checks for: closure, the presence of the Identity permutation,
and the presence of the inverse for each of the elements in the group. This
confirms that none of the polyhedra are true groups:
>>> from sympy.combinatorics.polyhedron import (
... tetrahedron, cube, octahedron, dodecahedron, icosahedron)
...
>>> polyhedra = (tetrahedron, cube, octahedron, dodecahedron, icosahedron)
>>> [h.pgroup.is_group for h in polyhedra]
...
[True, True, True, True, True]
Although tests in polyhedron's test suite check that powers of the
permutations in the groups generate all permutations of the vertices
of the polyhedron, here we also demonstrate the powers of the given
permutations create a complete group for the tetrahedron:
>>> from sympy.combinatorics import Permutation, PermutationGroup
>>> for h in polyhedra[:1]:
... G = h.pgroup
... perms = set()
... for g in G:
... for e in range(g.order()):
... p = tuple((g**e).array_form)
... perms.add(p)
...
... perms = [Permutation(p) for p in perms]
... assert PermutationGroup(perms).is_group
In addition to doing the above, the tests in the suite confirm that the
faces are all present after the application of each permutation.
References
==========
.. [1] https://dogschool.tripod.com/trianglegroup.html
"""
def _pgroup_of_double(polyh, ordered_faces, pgroup):
n = len(ordered_faces[0])
# the vertices of the double which sits inside a give polyhedron
# can be found by tracking the faces of the outer polyhedron.
# A map between face and the vertex of the double is made so that
# after rotation the position of the vertices can be located
fmap = dict(zip(ordered_faces,
range(len(ordered_faces))))
flat_faces = flatten(ordered_faces)
new_pgroup = []
for p in pgroup:
h = polyh.copy()
h.rotate(p)
c = h.corners
# reorder corners in the order they should appear when
# enumerating the faces
reorder = unflatten([c[j] for j in flat_faces], n)
# make them canonical
reorder = [tuple(map(as_int,
minlex(f, directed=False)))
for f in reorder]
# map face to vertex: the resulting list of vertices are the
# permutation that we seek for the double
new_pgroup.append(Perm([fmap[f] for f in reorder]))
return new_pgroup
tetrahedron_faces = [
(0, 1, 2), (0, 2, 3), (0, 3, 1), # upper 3
(1, 2, 3), # bottom
]
# cw from top
#
_t_pgroup = [
Perm([[1, 2, 3], [0]]), # cw from top
Perm([[0, 1, 2], [3]]), # cw from front face
Perm([[0, 3, 2], [1]]), # cw from back right face
Perm([[0, 3, 1], [2]]), # cw from back left face
Perm([[0, 1], [2, 3]]), # through front left edge
Perm([[0, 2], [1, 3]]), # through front right edge
Perm([[0, 3], [1, 2]]), # through back edge
]
tetrahedron = Polyhedron(
range(4),
tetrahedron_faces,
_t_pgroup)
cube_faces = [
(0, 1, 2, 3), # upper
(0, 1, 5, 4), (1, 2, 6, 5), (2, 3, 7, 6), (0, 3, 7, 4), # middle 4
(4, 5, 6, 7), # lower
]
# U, D, F, B, L, R = up, down, front, back, left, right
_c_pgroup = [Perm(p) for p in
[
[1, 2, 3, 0, 5, 6, 7, 4], # cw from top, U
[4, 0, 3, 7, 5, 1, 2, 6], # cw from F face
[4, 5, 1, 0, 7, 6, 2, 3], # cw from R face
[1, 0, 4, 5, 2, 3, 7, 6], # cw through UF edge
[6, 2, 1, 5, 7, 3, 0, 4], # cw through UR edge
[6, 7, 3, 2, 5, 4, 0, 1], # cw through UB edge
[3, 7, 4, 0, 2, 6, 5, 1], # cw through UL edge
[4, 7, 6, 5, 0, 3, 2, 1], # cw through FL edge
[6, 5, 4, 7, 2, 1, 0, 3], # cw through FR edge
[0, 3, 7, 4, 1, 2, 6, 5], # cw through UFL vertex
[5, 1, 0, 4, 6, 2, 3, 7], # cw through UFR vertex
[5, 6, 2, 1, 4, 7, 3, 0], # cw through UBR vertex
[7, 4, 0, 3, 6, 5, 1, 2], # cw through UBL
]]
cube = Polyhedron(
range(8),
cube_faces,
_c_pgroup)
octahedron_faces = [
(0, 1, 2), (0, 2, 3), (0, 3, 4), (0, 1, 4), # top 4
(1, 2, 5), (2, 3, 5), (3, 4, 5), (1, 4, 5), # bottom 4
]
octahedron = Polyhedron(
range(6),
octahedron_faces,
_pgroup_of_double(cube, cube_faces, _c_pgroup))
dodecahedron_faces = [
(0, 1, 2, 3, 4), # top
(0, 1, 6, 10, 5), (1, 2, 7, 11, 6), (2, 3, 8, 12, 7), # upper 5
(3, 4, 9, 13, 8), (0, 4, 9, 14, 5),
(5, 10, 16, 15, 14), (6, 10, 16, 17, 11), (7, 11, 17, 18,
12), # lower 5
(8, 12, 18, 19, 13), (9, 13, 19, 15, 14),
(15, 16, 17, 18, 19) # bottom
]
def _string_to_perm(s):
rv = [Perm(range(20))]
p = None
for si in s:
if si not in '01':
count = int(si) - 1
else:
count = 1
if si == '0':
p = _f0
elif si == '1':
p = _f1
rv.extend([p]*count)
return Perm.rmul(*rv)
# top face cw
_f0 = Perm([
1, 2, 3, 4, 0, 6, 7, 8, 9, 5, 11,
12, 13, 14, 10, 16, 17, 18, 19, 15])
# front face cw
_f1 = Perm([
5, 0, 4, 9, 14, 10, 1, 3, 13, 15,
6, 2, 8, 19, 16, 17, 11, 7, 12, 18])
# the strings below, like 0104 are shorthand for F0*F1*F0**4 and are
# the remaining 4 face rotations, 15 edge permutations, and the
# 10 vertex rotations.
_dodeca_pgroup = [_f0, _f1] + [_string_to_perm(s) for s in '''
0104 140 014 0410
010 1403 03104 04103 102
120 1304 01303 021302 03130
0412041 041204103 04120410 041204104 041204102
10 01 1402 0140 04102 0412 1204 1302 0130 03120'''.strip().split()]
dodecahedron = Polyhedron(
range(20),
dodecahedron_faces,
_dodeca_pgroup)
icosahedron_faces = [
(0, 1, 2), (0, 2, 3), (0, 3, 4), (0, 4, 5), (0, 1, 5),
(1, 6, 7), (1, 2, 7), (2, 7, 8), (2, 3, 8), (3, 8, 9),
(3, 4, 9), (4, 9, 10), (4, 5, 10), (5, 6, 10), (1, 5, 6),
(6, 7, 11), (7, 8, 11), (8, 9, 11), (9, 10, 11), (6, 10, 11)]
icosahedron = Polyhedron(
range(12),
icosahedron_faces,
_pgroup_of_double(
dodecahedron, dodecahedron_faces, _dodeca_pgroup))
return (tetrahedron, cube, octahedron, dodecahedron, icosahedron,
tetrahedron_faces, cube_faces, octahedron_faces,
dodecahedron_faces, icosahedron_faces)
# -----------------------------------------------------------------------
# Standard Polyhedron groups
#
# These are generated using _pgroup_calcs() above. However to save
# import time we encode them explicitly here.
# -----------------------------------------------------------------------
tetrahedron = Polyhedron(
Tuple(0, 1, 2, 3),
Tuple(
Tuple(0, 1, 2),
Tuple(0, 2, 3),
Tuple(0, 1, 3),
Tuple(1, 2, 3)),
Tuple(
Perm(1, 2, 3),
Perm(3)(0, 1, 2),
Perm(0, 3, 2),
Perm(0, 3, 1),
Perm(0, 1)(2, 3),
Perm(0, 2)(1, 3),
Perm(0, 3)(1, 2)
))
cube = Polyhedron(
Tuple(0, 1, 2, 3, 4, 5, 6, 7),
Tuple(
Tuple(0, 1, 2, 3),
Tuple(0, 1, 5, 4),
Tuple(1, 2, 6, 5),
Tuple(2, 3, 7, 6),
Tuple(0, 3, 7, 4),
Tuple(4, 5, 6, 7)),
Tuple(
Perm(0, 1, 2, 3)(4, 5, 6, 7),
Perm(0, 4, 5, 1)(2, 3, 7, 6),
Perm(0, 4, 7, 3)(1, 5, 6, 2),
Perm(0, 1)(2, 4)(3, 5)(6, 7),
Perm(0, 6)(1, 2)(3, 5)(4, 7),
Perm(0, 6)(1, 7)(2, 3)(4, 5),
Perm(0, 3)(1, 7)(2, 4)(5, 6),
Perm(0, 4)(1, 7)(2, 6)(3, 5),
Perm(0, 6)(1, 5)(2, 4)(3, 7),
Perm(1, 3, 4)(2, 7, 5),
Perm(7)(0, 5, 2)(3, 4, 6),
Perm(0, 5, 7)(1, 6, 3),
Perm(0, 7, 2)(1, 4, 6)))
octahedron = Polyhedron(
Tuple(0, 1, 2, 3, 4, 5),
Tuple(
Tuple(0, 1, 2),
Tuple(0, 2, 3),
Tuple(0, 3, 4),
Tuple(0, 1, 4),
Tuple(1, 2, 5),
Tuple(2, 3, 5),
Tuple(3, 4, 5),
Tuple(1, 4, 5)),
Tuple(
Perm(5)(1, 2, 3, 4),
Perm(0, 4, 5, 2),
Perm(0, 1, 5, 3),
Perm(0, 1)(2, 4)(3, 5),
Perm(0, 2)(1, 3)(4, 5),
Perm(0, 3)(1, 5)(2, 4),
Perm(0, 4)(1, 3)(2, 5),
Perm(0, 5)(1, 4)(2, 3),
Perm(0, 5)(1, 2)(3, 4),
Perm(0, 4, 1)(2, 3, 5),
Perm(0, 1, 2)(3, 4, 5),
Perm(0, 2, 3)(1, 5, 4),
Perm(0, 4, 3)(1, 5, 2)))
dodecahedron = Polyhedron(
Tuple(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19),
Tuple(
Tuple(0, 1, 2, 3, 4),
Tuple(0, 1, 6, 10, 5),
Tuple(1, 2, 7, 11, 6),
Tuple(2, 3, 8, 12, 7),
Tuple(3, 4, 9, 13, 8),
Tuple(0, 4, 9, 14, 5),
Tuple(5, 10, 16, 15, 14),
Tuple(6, 10, 16, 17, 11),
Tuple(7, 11, 17, 18, 12),
Tuple(8, 12, 18, 19, 13),
Tuple(9, 13, 19, 15, 14),
Tuple(15, 16, 17, 18, 19)),
Tuple(
Perm(0, 1, 2, 3, 4)(5, 6, 7, 8, 9)(10, 11, 12, 13, 14)(15, 16, 17, 18, 19),
Perm(0, 5, 10, 6, 1)(2, 4, 14, 16, 11)(3, 9, 15, 17, 7)(8, 13, 19, 18, 12),
Perm(0, 10, 17, 12, 3)(1, 6, 11, 7, 2)(4, 5, 16, 18, 8)(9, 14, 15, 19, 13),
Perm(0, 6, 17, 19, 9)(1, 11, 18, 13, 4)(2, 7, 12, 8, 3)(5, 10, 16, 15, 14),
Perm(0, 2, 12, 19, 14)(1, 7, 18, 15, 5)(3, 8, 13, 9, 4)(6, 11, 17, 16, 10),
Perm(0, 4, 9, 14, 5)(1, 3, 13, 15, 10)(2, 8, 19, 16, 6)(7, 12, 18, 17, 11),
Perm(0, 1)(2, 5)(3, 10)(4, 6)(7, 14)(8, 16)(9, 11)(12, 15)(13, 17)(18, 19),
Perm(0, 7)(1, 2)(3, 6)(4, 11)(5, 12)(8, 10)(9, 17)(13, 16)(14, 18)(15, 19),
Perm(0, 12)(1, 8)(2, 3)(4, 7)(5, 18)(6, 13)(9, 11)(10, 19)(14, 17)(15, 16),
Perm(0, 8)(1, 13)(2, 9)(3, 4)(5, 12)(6, 19)(7, 14)(10, 18)(11, 15)(16, 17),
Perm(0, 4)(1, 9)(2, 14)(3, 5)(6, 13)(7, 15)(8, 10)(11, 19)(12, 16)(17, 18),
Perm(0, 5)(1, 14)(2, 15)(3, 16)(4, 10)(6, 9)(7, 19)(8, 17)(11, 13)(12, 18),
Perm(0, 11)(1, 6)(2, 10)(3, 16)(4, 17)(5, 7)(8, 15)(9, 18)(12, 14)(13, 19),
Perm(0, 18)(1, 12)(2, 7)(3, 11)(4, 17)(5, 19)(6, 8)(9, 16)(10, 13)(14, 15),
Perm(0, 18)(1, 19)(2, 13)(3, 8)(4, 12)(5, 17)(6, 15)(7, 9)(10, 16)(11, 14),
Perm(0, 13)(1, 19)(2, 15)(3, 14)(4, 9)(5, 8)(6, 18)(7, 16)(10, 12)(11, 17),
Perm(0, 16)(1, 15)(2, 19)(3, 18)(4, 17)(5, 10)(6, 14)(7, 13)(8, 12)(9, 11),
Perm(0, 18)(1, 17)(2, 16)(3, 15)(4, 19)(5, 12)(6, 11)(7, 10)(8, 14)(9, 13),
Perm(0, 15)(1, 19)(2, 18)(3, 17)(4, 16)(5, 14)(6, 13)(7, 12)(8, 11)(9, 10),
Perm(0, 17)(1, 16)(2, 15)(3, 19)(4, 18)(5, 11)(6, 10)(7, 14)(8, 13)(9, 12),
Perm(0, 19)(1, 18)(2, 17)(3, 16)(4, 15)(5, 13)(6, 12)(7, 11)(8, 10)(9, 14),
Perm(1, 4, 5)(2, 9, 10)(3, 14, 6)(7, 13, 16)(8, 15, 11)(12, 19, 17),
Perm(19)(0, 6, 2)(3, 5, 11)(4, 10, 7)(8, 14, 17)(9, 16, 12)(13, 15, 18),
Perm(0, 11, 8)(1, 7, 3)(4, 6, 12)(5, 17, 13)(9, 10, 18)(14, 16, 19),
Perm(0, 7, 13)(1, 12, 9)(2, 8, 4)(5, 11, 19)(6, 18, 14)(10, 17, 15),
Perm(0, 3, 9)(1, 8, 14)(2, 13, 5)(6, 12, 15)(7, 19, 10)(11, 18, 16),
Perm(0, 14, 10)(1, 9, 16)(2, 13, 17)(3, 19, 11)(4, 15, 6)(7, 8, 18),
Perm(0, 16, 7)(1, 10, 11)(2, 5, 17)(3, 14, 18)(4, 15, 12)(8, 9, 19),
Perm(0, 16, 13)(1, 17, 8)(2, 11, 12)(3, 6, 18)(4, 10, 19)(5, 15, 9),
Perm(0, 11, 15)(1, 17, 14)(2, 18, 9)(3, 12, 13)(4, 7, 19)(5, 6, 16),
Perm(0, 8, 15)(1, 12, 16)(2, 18, 10)(3, 19, 5)(4, 13, 14)(6, 7, 17)))
icosahedron = Polyhedron(
Tuple(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11),
Tuple(
Tuple(0, 1, 2),
Tuple(0, 2, 3),
Tuple(0, 3, 4),
Tuple(0, 4, 5),
Tuple(0, 1, 5),
Tuple(1, 6, 7),
Tuple(1, 2, 7),
Tuple(2, 7, 8),
Tuple(2, 3, 8),
Tuple(3, 8, 9),
Tuple(3, 4, 9),
Tuple(4, 9, 10),
Tuple(4, 5, 10),
Tuple(5, 6, 10),
Tuple(1, 5, 6),
Tuple(6, 7, 11),
Tuple(7, 8, 11),
Tuple(8, 9, 11),
Tuple(9, 10, 11),
Tuple(6, 10, 11)),
Tuple(
Perm(11)(1, 2, 3, 4, 5)(6, 7, 8, 9, 10),
Perm(0, 5, 6, 7, 2)(3, 4, 10, 11, 8),
Perm(0, 1, 7, 8, 3)(4, 5, 6, 11, 9),
Perm(0, 2, 8, 9, 4)(1, 7, 11, 10, 5),
Perm(0, 3, 9, 10, 5)(1, 2, 8, 11, 6),
Perm(0, 4, 10, 6, 1)(2, 3, 9, 11, 7),
Perm(0, 1)(2, 5)(3, 6)(4, 7)(8, 10)(9, 11),
Perm(0, 2)(1, 3)(4, 7)(5, 8)(6, 9)(10, 11),
Perm(0, 3)(1, 9)(2, 4)(5, 8)(6, 11)(7, 10),
Perm(0, 4)(1, 9)(2, 10)(3, 5)(6, 8)(7, 11),
Perm(0, 5)(1, 4)(2, 10)(3, 6)(7, 9)(8, 11),
Perm(0, 6)(1, 5)(2, 10)(3, 11)(4, 7)(8, 9),
Perm(0, 7)(1, 2)(3, 6)(4, 11)(5, 8)(9, 10),
Perm(0, 8)(1, 9)(2, 3)(4, 7)(5, 11)(6, 10),
Perm(0, 9)(1, 11)(2, 10)(3, 4)(5, 8)(6, 7),
Perm(0, 10)(1, 9)(2, 11)(3, 6)(4, 5)(7, 8),
Perm(0, 11)(1, 6)(2, 10)(3, 9)(4, 8)(5, 7),
Perm(0, 11)(1, 8)(2, 7)(3, 6)(4, 10)(5, 9),
Perm(0, 11)(1, 10)(2, 9)(3, 8)(4, 7)(5, 6),
Perm(0, 11)(1, 7)(2, 6)(3, 10)(4, 9)(5, 8),
Perm(0, 11)(1, 9)(2, 8)(3, 7)(4, 6)(5, 10),
Perm(0, 5, 1)(2, 4, 6)(3, 10, 7)(8, 9, 11),
Perm(0, 1, 2)(3, 5, 7)(4, 6, 8)(9, 10, 11),
Perm(0, 2, 3)(1, 8, 4)(5, 7, 9)(6, 11, 10),
Perm(0, 3, 4)(1, 8, 10)(2, 9, 5)(6, 7, 11),
Perm(0, 4, 5)(1, 3, 10)(2, 9, 6)(7, 8, 11),
Perm(0, 10, 7)(1, 5, 6)(2, 4, 11)(3, 9, 8),
Perm(0, 6, 8)(1, 7, 2)(3, 5, 11)(4, 10, 9),
Perm(0, 7, 9)(1, 11, 4)(2, 8, 3)(5, 6, 10),
Perm(0, 8, 10)(1, 7, 6)(2, 11, 5)(3, 9, 4),
Perm(0, 9, 6)(1, 3, 11)(2, 8, 7)(4, 10, 5)))
tetrahedron_faces = [tuple(arg) for arg in tetrahedron.faces]
cube_faces = [tuple(arg) for arg in cube.faces]
octahedron_faces = [tuple(arg) for arg in octahedron.faces]
dodecahedron_faces = [tuple(arg) for arg in dodecahedron.faces]
icosahedron_faces = [tuple(arg) for arg in icosahedron.faces]
PK ]ZZZ�� / / sympy/combinatorics/prufer.pyfrom sympy.core import Basic
from sympy.core.containers import Tuple
from sympy.tensor.array import Array
from sympy.core.sympify import _sympify
from sympy.utilities.iterables import flatten, iterable
from sympy.utilities.misc import as_int
from collections import defaultdict
class Prufer(Basic):
"""
The Prufer correspondence is an algorithm that describes the
bijection between labeled trees and the Prufer code. A Prufer
code of a labeled tree is unique up to isomorphism and has
a length of n - 2.
Prufer sequences were first used by Heinz Prufer to give a
proof of Cayley's formula.
References
==========
.. [1] https://mathworld.wolfram.com/LabeledTree.html
"""
_prufer_repr = None
_tree_repr = None
_nodes = None
_rank = None
@property
def prufer_repr(self):
"""Returns Prufer sequence for the Prufer object.
This sequence is found by removing the highest numbered vertex,
recording the node it was attached to, and continuing until only
two vertices remain. The Prufer sequence is the list of recorded nodes.
Examples
========
>>> from sympy.combinatorics.prufer import Prufer
>>> Prufer([[0, 3], [1, 3], [2, 3], [3, 4], [4, 5]]).prufer_repr
[3, 3, 3, 4]
>>> Prufer([1, 0, 0]).prufer_repr
[1, 0, 0]
See Also
========
to_prufer
"""
if self._prufer_repr is None:
self._prufer_repr = self.to_prufer(self._tree_repr[:], self.nodes)
return self._prufer_repr
@property
def tree_repr(self):
"""Returns the tree representation of the Prufer object.
Examples
========
>>> from sympy.combinatorics.prufer import Prufer
>>> Prufer([[0, 3], [1, 3], [2, 3], [3, 4], [4, 5]]).tree_repr
[[0, 3], [1, 3], [2, 3], [3, 4], [4, 5]]
>>> Prufer([1, 0, 0]).tree_repr
[[1, 2], [0, 1], [0, 3], [0, 4]]
See Also
========
to_tree
"""
if self._tree_repr is None:
self._tree_repr = self.to_tree(self._prufer_repr[:])
return self._tree_repr
@property
def nodes(self):
"""Returns the number of nodes in the tree.
Examples
========
>>> from sympy.combinatorics.prufer import Prufer
>>> Prufer([[0, 3], [1, 3], [2, 3], [3, 4], [4, 5]]).nodes
6
>>> Prufer([1, 0, 0]).nodes
5
"""
return self._nodes
@property
def rank(self):
"""Returns the rank of the Prufer sequence.
Examples
========
>>> from sympy.combinatorics.prufer import Prufer
>>> p = Prufer([[0, 3], [1, 3], [2, 3], [3, 4], [4, 5]])
>>> p.rank
778
>>> p.next(1).rank
779
>>> p.prev().rank
777
See Also
========
prufer_rank, next, prev, size
"""
if self._rank is None:
self._rank = self.prufer_rank()
return self._rank
@property
def size(self):
"""Return the number of possible trees of this Prufer object.
Examples
========
>>> from sympy.combinatorics.prufer import Prufer
>>> Prufer([0]*4).size == Prufer([6]*4).size == 1296
True
See Also
========
prufer_rank, rank, next, prev
"""
return self.prev(self.rank).prev().rank + 1
@staticmethod
def to_prufer(tree, n):
"""Return the Prufer sequence for a tree given as a list of edges where
``n`` is the number of nodes in the tree.
Examples
========
>>> from sympy.combinatorics.prufer import Prufer
>>> a = Prufer([[0, 1], [0, 2], [0, 3]])
>>> a.prufer_repr
[0, 0]
>>> Prufer.to_prufer([[0, 1], [0, 2], [0, 3]], 4)
[0, 0]
See Also
========
prufer_repr: returns Prufer sequence of a Prufer object.
"""
d = defaultdict(int)
L = []
for edge in tree:
# Increment the value of the corresponding
# node in the degree list as we encounter an
# edge involving it.
d[edge[0]] += 1
d[edge[1]] += 1
for i in range(n - 2):
# find the smallest leaf
for x in range(n):
if d[x] == 1:
break
# find the node it was connected to
y = None
for edge in tree:
if x == edge[0]:
y = edge[1]
elif x == edge[1]:
y = edge[0]
if y is not None:
break
# record and update
L.append(y)
for j in (x, y):
d[j] -= 1
if not d[j]:
d.pop(j)
tree.remove(edge)
return L
@staticmethod
def to_tree(prufer):
"""Return the tree (as a list of edges) of the given Prufer sequence.
Examples
========
>>> from sympy.combinatorics.prufer import Prufer
>>> a = Prufer([0, 2], 4)
>>> a.tree_repr
[[0, 1], [0, 2], [2, 3]]
>>> Prufer.to_tree([0, 2])
[[0, 1], [0, 2], [2, 3]]
References
==========
.. [1] https://hamberg.no/erlend/posts/2010-11-06-prufer-sequence-compact-tree-representation.html
See Also
========
tree_repr: returns tree representation of a Prufer object.
"""
tree = []
last = []
n = len(prufer) + 2
d = defaultdict(lambda: 1)
for p in prufer:
d[p] += 1
for i in prufer:
for j in range(n):
# find the smallest leaf (degree = 1)
if d[j] == 1:
break
# (i, j) is the new edge that we append to the tree
# and remove from the degree dictionary
d[i] -= 1
d[j] -= 1
tree.append(sorted([i, j]))
last = [i for i in range(n) if d[i] == 1] or [0, 1]
tree.append(last)
return tree
@staticmethod
def edges(*runs):
"""Return a list of edges and the number of nodes from the given runs
that connect nodes in an integer-labelled tree.
All node numbers will be shifted so that the minimum node is 0. It is
not a problem if edges are repeated in the runs; only unique edges are
returned. There is no assumption made about what the range of the node
labels should be, but all nodes from the smallest through the largest
must be present.
Examples
========
>>> from sympy.combinatorics.prufer import Prufer
>>> Prufer.edges([1, 2, 3], [2, 4, 5]) # a T
([[0, 1], [1, 2], [1, 3], [3, 4]], 5)
Duplicate edges are removed:
>>> Prufer.edges([0, 1, 2, 3], [1, 4, 5], [1, 4, 6]) # a K
([[0, 1], [1, 2], [1, 4], [2, 3], [4, 5], [4, 6]], 7)
"""
e = set()
nmin = runs[0][0]
for r in runs:
for i in range(len(r) - 1):
a, b = r[i: i + 2]
if b < a:
a, b = b, a
e.add((a, b))
rv = []
got = set()
nmin = nmax = None
for ei in e:
got.update(ei)
nmin = min(ei[0], nmin) if nmin is not None else ei[0]
nmax = max(ei[1], nmax) if nmax is not None else ei[1]
rv.append(list(ei))
missing = set(range(nmin, nmax + 1)) - got
if missing:
missing = [i + nmin for i in missing]
if len(missing) == 1:
msg = 'Node %s is missing.' % missing.pop()
else:
msg = 'Nodes %s are missing.' % sorted(missing)
raise ValueError(msg)
if nmin != 0:
for i, ei in enumerate(rv):
rv[i] = [n - nmin for n in ei]
nmax -= nmin
return sorted(rv), nmax + 1
def prufer_rank(self):
"""Computes the rank of a Prufer sequence.
Examples
========
>>> from sympy.combinatorics.prufer import Prufer
>>> a = Prufer([[0, 1], [0, 2], [0, 3]])
>>> a.prufer_rank()
0
See Also
========
rank, next, prev, size
"""
r = 0
p = 1
for i in range(self.nodes - 3, -1, -1):
r += p*self.prufer_repr[i]
p *= self.nodes
return r
@classmethod
def unrank(self, rank, n):
"""Finds the unranked Prufer sequence.
Examples
========
>>> from sympy.combinatorics.prufer import Prufer
>>> Prufer.unrank(0, 4)
Prufer([0, 0])
"""
n, rank = as_int(n), as_int(rank)
L = defaultdict(int)
for i in range(n - 3, -1, -1):
L[i] = rank % n
rank = (rank - L[i])//n
return Prufer([L[i] for i in range(len(L))])
def __new__(cls, *args, **kw_args):
"""The constructor for the Prufer object.
Examples
========
>>> from sympy.combinatorics.prufer import Prufer
A Prufer object can be constructed from a list of edges:
>>> a = Prufer([[0, 1], [0, 2], [0, 3]])
>>> a.prufer_repr
[0, 0]
If the number of nodes is given, no checking of the nodes will
be performed; it will be assumed that nodes 0 through n - 1 are
present:
>>> Prufer([[0, 1], [0, 2], [0, 3]], 4)
Prufer([[0, 1], [0, 2], [0, 3]], 4)
A Prufer object can be constructed from a Prufer sequence:
>>> b = Prufer([1, 3])
>>> b.tree_repr
[[0, 1], [1, 3], [2, 3]]
"""
arg0 = Array(args[0]) if args[0] else Tuple()
args = (arg0,) + tuple(_sympify(arg) for arg in args[1:])
ret_obj = Basic.__new__(cls, *args, **kw_args)
args = [list(args[0])]
if args[0] and iterable(args[0][0]):
if not args[0][0]:
raise ValueError(
'Prufer expects at least one edge in the tree.')
if len(args) > 1:
nnodes = args[1]
else:
nodes = set(flatten(args[0]))
nnodes = max(nodes) + 1
if nnodes != len(nodes):
missing = set(range(nnodes)) - nodes
if len(missing) == 1:
msg = 'Node %s is missing.' % missing.pop()
else:
msg = 'Nodes %s are missing.' % sorted(missing)
raise ValueError(msg)
ret_obj._tree_repr = [list(i) for i in args[0]]
ret_obj._nodes = nnodes
else:
ret_obj._prufer_repr = args[0]
ret_obj._nodes = len(ret_obj._prufer_repr) + 2
return ret_obj
def next(self, delta=1):
"""Generates the Prufer sequence that is delta beyond the current one.
Examples
========
>>> from sympy.combinatorics.prufer import Prufer
>>> a = Prufer([[0, 1], [0, 2], [0, 3]])
>>> b = a.next(1) # == a.next()
>>> b.tree_repr
[[0, 2], [0, 1], [1, 3]]
>>> b.rank
1
See Also
========
prufer_rank, rank, prev, size
"""
return Prufer.unrank(self.rank + delta, self.nodes)
def prev(self, delta=1):
"""Generates the Prufer sequence that is -delta before the current one.
Examples
========
>>> from sympy.combinatorics.prufer import Prufer
>>> a = Prufer([[0, 1], [1, 2], [2, 3], [1, 4]])
>>> a.rank
36
>>> b = a.prev()
>>> b
Prufer([1, 2, 0])
>>> b.rank
35
See Also
========
prufer_rank, rank, next, size
"""
return Prufer.unrank(self.rank -delta, self.nodes)
PK ]ZZZϩfy�B �B & sympy/combinatorics/rewritingsystem.pyfrom collections import deque
from sympy.combinatorics.rewritingsystem_fsm import StateMachine
class RewritingSystem:
'''
A class implementing rewriting systems for `FpGroup`s.
References
==========
.. [1] Epstein, D., Holt, D. and Rees, S. (1991).
The use of Knuth-Bendix methods to solve the word problem in automatic groups.
Journal of Symbolic Computation, 12(4-5), pp.397-414.
.. [2] GAP's Manual on its KBMAG package
https://www.gap-system.org/Manuals/pkg/kbmag-1.5.3/doc/manual.pdf
'''
def __init__(self, group):
self.group = group
self.alphabet = group.generators
self._is_confluent = None
# these values are taken from [2]
self.maxeqns = 32767 # max rules
self.tidyint = 100 # rules before tidying
# _max_exceeded is True if maxeqns is exceeded
# at any point
self._max_exceeded = False
# Reduction automaton
self.reduction_automaton = None
self._new_rules = {}
# dictionary of reductions
self.rules = {}
self.rules_cache = deque([], 50)
self._init_rules()
# All the transition symbols in the automaton
generators = list(self.alphabet)
generators += [gen**-1 for gen in generators]
# Create a finite state machine as an instance of the StateMachine object
self.reduction_automaton = StateMachine('Reduction automaton for '+ repr(self.group), generators)
self.construct_automaton()
def set_max(self, n):
'''
Set the maximum number of rules that can be defined
'''
if n > self.maxeqns:
self._max_exceeded = False
self.maxeqns = n
return
@property
def is_confluent(self):
'''
Return `True` if the system is confluent
'''
if self._is_confluent is None:
self._is_confluent = self._check_confluence()
return self._is_confluent
def _init_rules(self):
identity = self.group.free_group.identity
for r in self.group.relators:
self.add_rule(r, identity)
self._remove_redundancies()
return
def _add_rule(self, r1, r2):
'''
Add the rule r1 -> r2 with no checking or further
deductions
'''
if len(self.rules) + 1 > self.maxeqns:
self._is_confluent = self._check_confluence()
self._max_exceeded = True
raise RuntimeError("Too many rules were defined.")
self.rules[r1] = r2
# Add the newly added rule to the `new_rules` dictionary.
if self.reduction_automaton:
self._new_rules[r1] = r2
def add_rule(self, w1, w2, check=False):
new_keys = set()
if w1 == w2:
return new_keys
if w1 < w2:
w1, w2 = w2, w1
if (w1, w2) in self.rules_cache:
return new_keys
self.rules_cache.append((w1, w2))
s1, s2 = w1, w2
# The following is the equivalent of checking
# s1 for overlaps with the implicit reductions
# {g*g**-1 -> <identity>} and {g**-1*g -> <identity>}
# for any generator g without installing the
# redundant rules that would result from processing
# the overlaps. See [1], Section 3 for details.
if len(s1) - len(s2) < 3:
if s1 not in self.rules:
new_keys.add(s1)
if not check:
self._add_rule(s1, s2)
if s2**-1 > s1**-1 and s2**-1 not in self.rules:
new_keys.add(s2**-1)
if not check:
self._add_rule(s2**-1, s1**-1)
# overlaps on the right
while len(s1) - len(s2) > -1:
g = s1[len(s1)-1]
s1 = s1.subword(0, len(s1)-1)
s2 = s2*g**-1
if len(s1) - len(s2) < 0:
if s2 not in self.rules:
if not check:
self._add_rule(s2, s1)
new_keys.add(s2)
elif len(s1) - len(s2) < 3:
new = self.add_rule(s1, s2, check)
new_keys.update(new)
# overlaps on the left
while len(w1) - len(w2) > -1:
g = w1[0]
w1 = w1.subword(1, len(w1))
w2 = g**-1*w2
if len(w1) - len(w2) < 0:
if w2 not in self.rules:
if not check:
self._add_rule(w2, w1)
new_keys.add(w2)
elif len(w1) - len(w2) < 3:
new = self.add_rule(w1, w2, check)
new_keys.update(new)
return new_keys
def _remove_redundancies(self, changes=False):
'''
Reduce left- and right-hand sides of reduction rules
and remove redundant equations (i.e. those for which
lhs == rhs). If `changes` is `True`, return a set
containing the removed keys and a set containing the
added keys
'''
removed = set()
added = set()
rules = self.rules.copy()
for r in rules:
v = self.reduce(r, exclude=r)
w = self.reduce(rules[r])
if v != r:
del self.rules[r]
removed.add(r)
if v > w:
added.add(v)
self.rules[v] = w
elif v < w:
added.add(w)
self.rules[w] = v
else:
self.rules[v] = w
if changes:
return removed, added
return
def make_confluent(self, check=False):
'''
Try to make the system confluent using the Knuth-Bendix
completion algorithm
'''
if self._max_exceeded:
return self._is_confluent
lhs = list(self.rules.keys())
def _overlaps(r1, r2):
len1 = len(r1)
len2 = len(r2)
result = []
for j in range(1, len1 + len2):
if (r1.subword(len1 - j, len1 + len2 - j, strict=False)
== r2.subword(j - len1, j, strict=False)):
a = r1.subword(0, len1-j, strict=False)
a = a*r2.subword(0, j-len1, strict=False)
b = r2.subword(j-len1, j, strict=False)
c = r2.subword(j, len2, strict=False)
c = c*r1.subword(len1 + len2 - j, len1, strict=False)
result.append(a*b*c)
return result
def _process_overlap(w, r1, r2, check):
s = w.eliminate_word(r1, self.rules[r1])
s = self.reduce(s)
t = w.eliminate_word(r2, self.rules[r2])
t = self.reduce(t)
if s != t:
if check:
# system not confluent
return [0]
try:
new_keys = self.add_rule(t, s, check)
return new_keys
except RuntimeError:
return False
return
added = 0
i = 0
while i < len(lhs):
r1 = lhs[i]
i += 1
# j could be i+1 to not
# check each pair twice but lhs
# is extended in the loop and the new
# elements have to be checked with the
# preceding ones. there is probably a better way
# to handle this
j = 0
while j < len(lhs):
r2 = lhs[j]
j += 1
if r1 == r2:
continue
overlaps = _overlaps(r1, r2)
overlaps.extend(_overlaps(r1**-1, r2))
if not overlaps:
continue
for w in overlaps:
new_keys = _process_overlap(w, r1, r2, check)
if new_keys:
if check:
return False
lhs.extend(new_keys)
added += len(new_keys)
elif new_keys == False:
# too many rules were added so the process
# couldn't complete
return self._is_confluent
if added > self.tidyint and not check:
# tidy up
r, a = self._remove_redundancies(changes=True)
added = 0
if r:
# reset i since some elements were removed
i = min(lhs.index(s) for s in r)
lhs = [l for l in lhs if l not in r]
lhs.extend(a)
if r1 in r:
# r1 was removed as redundant
break
self._is_confluent = True
if not check:
self._remove_redundancies()
return True
def _check_confluence(self):
return self.make_confluent(check=True)
def reduce(self, word, exclude=None):
'''
Apply reduction rules to `word` excluding the reduction rule
for the lhs equal to `exclude`
'''
rules = {r: self.rules[r] for r in self.rules if r != exclude}
# the following is essentially `eliminate_words()` code from the
# `FreeGroupElement` class, the only difference being the first
# "if" statement
again = True
new = word
while again:
again = False
for r in rules:
prev = new
if rules[r]**-1 > r**-1:
new = new.eliminate_word(r, rules[r], _all=True, inverse=False)
else:
new = new.eliminate_word(r, rules[r], _all=True)
if new != prev:
again = True
return new
def _compute_inverse_rules(self, rules):
'''
Compute the inverse rules for a given set of rules.
The inverse rules are used in the automaton for word reduction.
Arguments:
rules (dictionary): Rules for which the inverse rules are to computed.
Returns:
Dictionary of inverse_rules.
'''
inverse_rules = {}
for r in rules:
rule_key_inverse = r**-1
rule_value_inverse = (rules[r])**-1
if (rule_value_inverse < rule_key_inverse):
inverse_rules[rule_key_inverse] = rule_value_inverse
else:
inverse_rules[rule_value_inverse] = rule_key_inverse
return inverse_rules
def construct_automaton(self):
'''
Construct the automaton based on the set of reduction rules of the system.
Automata Design:
The accept states of the automaton are the proper prefixes of the left hand side of the rules.
The complete left hand side of the rules are the dead states of the automaton.
'''
self._add_to_automaton(self.rules)
def _add_to_automaton(self, rules):
'''
Add new states and transitions to the automaton.
Summary:
States corresponding to the new rules added to the system are computed and added to the automaton.
Transitions in the previously added states are also modified if necessary.
Arguments:
rules (dictionary) -- Dictionary of the newly added rules.
'''
# Automaton variables
automaton_alphabet = []
proper_prefixes = {}
# compute the inverses of all the new rules added
all_rules = rules
inverse_rules = self._compute_inverse_rules(all_rules)
all_rules.update(inverse_rules)
# Keep track of the accept_states.
accept_states = []
for rule in all_rules:
# The symbols present in the new rules are the symbols to be verified at each state.
# computes the automaton_alphabet, as the transitions solely depend upon the new states.
automaton_alphabet += rule.letter_form_elm
# Compute the proper prefixes for every rule.
proper_prefixes[rule] = []
letter_word_array = list(rule.letter_form_elm)
len_letter_word_array = len(letter_word_array)
for i in range (1, len_letter_word_array):
letter_word_array[i] = letter_word_array[i-1]*letter_word_array[i]
# Add accept states.
elem = letter_word_array[i-1]
if elem not in self.reduction_automaton.states:
self.reduction_automaton.add_state(elem, state_type='a')
accept_states.append(elem)
proper_prefixes[rule] = letter_word_array
# Check for overlaps between dead and accept states.
if rule in accept_states:
self.reduction_automaton.states[rule].state_type = 'd'
self.reduction_automaton.states[rule].rh_rule = all_rules[rule]
accept_states.remove(rule)
# Add dead states
if rule not in self.reduction_automaton.states:
self.reduction_automaton.add_state(rule, state_type='d', rh_rule=all_rules[rule])
automaton_alphabet = set(automaton_alphabet)
# Add new transitions for every state.
for state in self.reduction_automaton.states:
current_state_name = state
current_state_type = self.reduction_automaton.states[state].state_type
# Transitions will be modified only when suffixes of the current_state
# belongs to the proper_prefixes of the new rules.
# The rest are ignored if they cannot lead to a dead state after a finite number of transisitons.
if current_state_type == 's':
for letter in automaton_alphabet:
if letter in self.reduction_automaton.states:
self.reduction_automaton.states[state].add_transition(letter, letter)
else:
self.reduction_automaton.states[state].add_transition(letter, current_state_name)
elif current_state_type == 'a':
# Check if the transition to any new state in possible.
for letter in automaton_alphabet:
_next = current_state_name*letter
while len(_next) and _next not in self.reduction_automaton.states:
_next = _next.subword(1, len(_next))
if not len(_next):
_next = 'start'
self.reduction_automaton.states[state].add_transition(letter, _next)
# Add transitions for new states. All symbols used in the automaton are considered here.
# Ignore this if `reduction_automaton.automaton_alphabet` = `automaton_alphabet`.
if len(self.reduction_automaton.automaton_alphabet) != len(automaton_alphabet):
for state in accept_states:
current_state_name = state
for letter in self.reduction_automaton.automaton_alphabet:
_next = current_state_name*letter
while len(_next) and _next not in self.reduction_automaton.states:
_next = _next.subword(1, len(_next))
if not len(_next):
_next = 'start'
self.reduction_automaton.states[state].add_transition(letter, _next)
def reduce_using_automaton(self, word):
'''
Reduce a word using an automaton.
Summary:
All the symbols of the word are stored in an array and are given as the input to the automaton.
If the automaton reaches a dead state that subword is replaced and the automaton is run from the beginning.
The complete word has to be replaced when the word is read and the automaton reaches a dead state.
So, this process is repeated until the word is read completely and the automaton reaches the accept state.
Arguments:
word (instance of FreeGroupElement) -- Word that needs to be reduced.
'''
# Modify the automaton if new rules are found.
if self._new_rules:
self._add_to_automaton(self._new_rules)
self._new_rules = {}
flag = 1
while flag:
flag = 0
current_state = self.reduction_automaton.states['start']
for i, s in enumerate(word.letter_form_elm):
next_state_name = current_state.transitions[s]
next_state = self.reduction_automaton.states[next_state_name]
if next_state.state_type == 'd':
subst = next_state.rh_rule
word = word.substituted_word(i - len(next_state_name) + 1, i+1, subst)
flag = 1
break
current_state = next_state
return word
PK ]ZZZ����� � * sympy/combinatorics/rewritingsystem_fsm.pyclass State:
'''
A representation of a state managed by a ``StateMachine``.
Attributes:
name (instance of FreeGroupElement or string) -- State name which is also assigned to the Machine.
transisitons (OrderedDict) -- Represents all the transitions of the state object.
state_type (string) -- Denotes the type (accept/start/dead) of the state.
rh_rule (instance of FreeGroupElement) -- right hand rule for dead state.
state_machine (instance of StateMachine object) -- The finite state machine that the state belongs to.
'''
def __init__(self, name, state_machine, state_type=None, rh_rule=None):
self.name = name
self.transitions = {}
self.state_machine = state_machine
self.state_type = state_type[0]
self.rh_rule = rh_rule
def add_transition(self, letter, state):
'''
Add a transition from the current state to a new state.
Keyword Arguments:
letter -- The alphabet element the current state reads to make the state transition.
state -- This will be an instance of the State object which represents a new state after in the transition after the alphabet is read.
'''
self.transitions[letter] = state
class StateMachine:
'''
Representation of a finite state machine the manages the states and the transitions of the automaton.
Attributes:
states (dictionary) -- Collection of all registered `State` objects.
name (str) -- Name of the state machine.
'''
def __init__(self, name, automaton_alphabet):
self.name = name
self.automaton_alphabet = automaton_alphabet
self.states = {} # Contains all the states in the machine.
self.add_state('start', state_type='s')
def add_state(self, state_name, state_type=None, rh_rule=None):
'''
Instantiate a state object and stores it in the 'states' dictionary.
Arguments:
state_name (instance of FreeGroupElement or string) -- name of the new states.
state_type (string) -- Denotes the type (accept/start/dead) of the state added.
rh_rule (instance of FreeGroupElement) -- right hand rule for dead state.
'''
new_state = State(state_name, self, state_type, rh_rule)
self.states[state_name] = new_state
def __repr__(self):
return "%s" % (self.name)
PK ]ZZZ�u'U U # sympy/combinatorics/schur_number.py"""
The Schur number S(k) is the largest integer n for which the interval [1,n]
can be partitioned into k sum-free sets.(https://mathworld.wolfram.com/SchurNumber.html)
"""
import math
from sympy.core import S
from sympy.core.basic import Basic
from sympy.core.function import Function
from sympy.core.numbers import Integer
class SchurNumber(Function):
r"""
This function creates a SchurNumber object
which is evaluated for `k \le 5` otherwise only
the lower bound information can be retrieved.
Examples
========
>>> from sympy.combinatorics.schur_number import SchurNumber
Since S(3) = 13, hence the output is a number
>>> SchurNumber(3)
13
We do not know the Schur number for values greater than 5, hence
only the object is returned
>>> SchurNumber(6)
SchurNumber(6)
Now, the lower bound information can be retrieved using lower_bound()
method
>>> SchurNumber(6).lower_bound()
536
"""
@classmethod
def eval(cls, k):
if k.is_Number:
if k is S.Infinity:
return S.Infinity
if k.is_zero:
return S.Zero
if not k.is_integer or k.is_negative:
raise ValueError("k should be a positive integer")
first_known_schur_numbers = {1: 1, 2: 4, 3: 13, 4: 44, 5: 160}
if k <= 5:
return Integer(first_known_schur_numbers[k])
def lower_bound(self):
f_ = self.args[0]
# Improved lower bounds known for S(6) and S(7)
if f_ == 6:
return Integer(536)
if f_ == 7:
return Integer(1680)
# For other cases, use general expression
if f_.is_Integer:
return 3*self.func(f_ - 1).lower_bound() - 1
return (3**f_ - 1)/2
def _schur_subsets_number(n):
if n is S.Infinity:
raise ValueError("Input must be finite")
if n <= 0:
raise ValueError("n must be a non-zero positive integer.")
elif n <= 3:
min_k = 1
else:
min_k = math.ceil(math.log(2*n + 1, 3))
return Integer(min_k)
def schur_partition(n):
"""
This function returns the partition in the minimum number of sum-free subsets
according to the lower bound given by the Schur Number.
Parameters
==========
n: a number
n is the upper limit of the range [1, n] for which we need to find and
return the minimum number of free subsets according to the lower bound
of schur number
Returns
=======
List of lists
List of the minimum number of sum-free subsets
Notes
=====
It is possible for some n to make the partition into less
subsets since the only known Schur numbers are:
S(1) = 1, S(2) = 4, S(3) = 13, S(4) = 44.
e.g for n = 44 the lower bound from the function above is 5 subsets but it has been proven
that can be done with 4 subsets.
Examples
========
For n = 1, 2, 3 the answer is the set itself
>>> from sympy.combinatorics.schur_number import schur_partition
>>> schur_partition(2)
[[1, 2]]
For n > 3, the answer is the minimum number of sum-free subsets:
>>> schur_partition(5)
[[3, 2], [5], [1, 4]]
>>> schur_partition(8)
[[3, 2], [6, 5, 8], [1, 4, 7]]
"""
if isinstance(n, Basic) and not n.is_Number:
raise ValueError("Input value must be a number")
number_of_subsets = _schur_subsets_number(n)
if n == 1:
sum_free_subsets = [[1]]
elif n == 2:
sum_free_subsets = [[1, 2]]
elif n == 3:
sum_free_subsets = [[1, 2, 3]]
else:
sum_free_subsets = [[1, 4], [2, 3]]
while len(sum_free_subsets) < number_of_subsets:
sum_free_subsets = _generate_next_list(sum_free_subsets, n)
missed_elements = [3*k + 1 for k in range(len(sum_free_subsets), (n-1)//3 + 1)]
sum_free_subsets[-1] += missed_elements
return sum_free_subsets
def _generate_next_list(current_list, n):
new_list = []
for item in current_list:
temp_1 = [number*3 for number in item if number*3 <= n]
temp_2 = [number*3 - 1 for number in item if number*3 - 1 <= n]
new_item = temp_1 + temp_2
new_list.append(new_item)
last_list = [3*k + 1 for k in range(len(current_list)+1) if 3*k + 1 <= n]
new_list.append(last_list)
current_list = new_list
return current_list
PK ]ZZZ {�.�> �> sympy/combinatorics/subsets.pyfrom itertools import combinations
from sympy.combinatorics.graycode import GrayCode
class Subset():
"""
Represents a basic subset object.
Explanation
===========
We generate subsets using essentially two techniques,
binary enumeration and lexicographic enumeration.
The Subset class takes two arguments, the first one
describes the initial subset to consider and the second
describes the superset.
Examples
========
>>> from sympy.combinatorics import Subset
>>> a = Subset(['c', 'd'], ['a', 'b', 'c', 'd'])
>>> a.next_binary().subset
['b']
>>> a.prev_binary().subset
['c']
"""
_rank_binary = None
_rank_lex = None
_rank_graycode = None
_subset = None
_superset = None
def __new__(cls, subset, superset):
"""
Default constructor.
It takes the ``subset`` and its ``superset`` as its parameters.
Examples
========
>>> from sympy.combinatorics import Subset
>>> a = Subset(['c', 'd'], ['a', 'b', 'c', 'd'])
>>> a.subset
['c', 'd']
>>> a.superset
['a', 'b', 'c', 'd']
>>> a.size
2
"""
if len(subset) > len(superset):
raise ValueError('Invalid arguments have been provided. The '
'superset must be larger than the subset.')
for elem in subset:
if elem not in superset:
raise ValueError('The superset provided is invalid as it does '
'not contain the element {}'.format(elem))
obj = object.__new__(cls)
obj._subset = subset
obj._superset = superset
return obj
def __eq__(self, other):
"""Return a boolean indicating whether a == b on the basis of
whether both objects are of the class Subset and if the values
of the subset and superset attributes are the same.
"""
if not isinstance(other, Subset):
return NotImplemented
return self.subset == other.subset and self.superset == other.superset
def iterate_binary(self, k):
"""
This is a helper function. It iterates over the
binary subsets by ``k`` steps. This variable can be
both positive or negative.
Examples
========
>>> from sympy.combinatorics import Subset
>>> a = Subset(['c', 'd'], ['a', 'b', 'c', 'd'])
>>> a.iterate_binary(-2).subset
['d']
>>> a = Subset(['a', 'b', 'c'], ['a', 'b', 'c', 'd'])
>>> a.iterate_binary(2).subset
[]
See Also
========
next_binary, prev_binary
"""
bin_list = Subset.bitlist_from_subset(self.subset, self.superset)
n = (int(''.join(bin_list), 2) + k) % 2**self.superset_size
bits = bin(n)[2:].rjust(self.superset_size, '0')
return Subset.subset_from_bitlist(self.superset, bits)
def next_binary(self):
"""
Generates the next binary ordered subset.
Examples
========
>>> from sympy.combinatorics import Subset
>>> a = Subset(['c', 'd'], ['a', 'b', 'c', 'd'])
>>> a.next_binary().subset
['b']
>>> a = Subset(['a', 'b', 'c', 'd'], ['a', 'b', 'c', 'd'])
>>> a.next_binary().subset
[]
See Also
========
prev_binary, iterate_binary
"""
return self.iterate_binary(1)
def prev_binary(self):
"""
Generates the previous binary ordered subset.
Examples
========
>>> from sympy.combinatorics import Subset
>>> a = Subset([], ['a', 'b', 'c', 'd'])
>>> a.prev_binary().subset
['a', 'b', 'c', 'd']
>>> a = Subset(['c', 'd'], ['a', 'b', 'c', 'd'])
>>> a.prev_binary().subset
['c']
See Also
========
next_binary, iterate_binary
"""
return self.iterate_binary(-1)
def next_lexicographic(self):
"""
Generates the next lexicographically ordered subset.
Examples
========
>>> from sympy.combinatorics import Subset
>>> a = Subset(['c', 'd'], ['a', 'b', 'c', 'd'])
>>> a.next_lexicographic().subset
['d']
>>> a = Subset(['d'], ['a', 'b', 'c', 'd'])
>>> a.next_lexicographic().subset
[]
See Also
========
prev_lexicographic
"""
i = self.superset_size - 1
indices = Subset.subset_indices(self.subset, self.superset)
if i in indices:
if i - 1 in indices:
indices.remove(i - 1)
else:
indices.remove(i)
i = i - 1
while i >= 0 and i not in indices:
i = i - 1
if i >= 0:
indices.remove(i)
indices.append(i+1)
else:
while i not in indices and i >= 0:
i = i - 1
indices.append(i + 1)
ret_set = []
super_set = self.superset
for i in indices:
ret_set.append(super_set[i])
return Subset(ret_set, super_set)
def prev_lexicographic(self):
"""
Generates the previous lexicographically ordered subset.
Examples
========
>>> from sympy.combinatorics import Subset
>>> a = Subset([], ['a', 'b', 'c', 'd'])
>>> a.prev_lexicographic().subset
['d']
>>> a = Subset(['c','d'], ['a', 'b', 'c', 'd'])
>>> a.prev_lexicographic().subset
['c']
See Also
========
next_lexicographic
"""
i = self.superset_size - 1
indices = Subset.subset_indices(self.subset, self.superset)
while i >= 0 and i not in indices:
i = i - 1
if i == 0 or i - 1 in indices:
indices.remove(i)
else:
if i >= 0:
indices.remove(i)
indices.append(i - 1)
indices.append(self.superset_size - 1)
ret_set = []
super_set = self.superset
for i in indices:
ret_set.append(super_set[i])
return Subset(ret_set, super_set)
def iterate_graycode(self, k):
"""
Helper function used for prev_gray and next_gray.
It performs ``k`` step overs to get the respective Gray codes.
Examples
========
>>> from sympy.combinatorics import Subset
>>> a = Subset([1, 2, 3], [1, 2, 3, 4])
>>> a.iterate_graycode(3).subset
[1, 4]
>>> a.iterate_graycode(-2).subset
[1, 2, 4]
See Also
========
next_gray, prev_gray
"""
unranked_code = GrayCode.unrank(self.superset_size,
(self.rank_gray + k) % self.cardinality)
return Subset.subset_from_bitlist(self.superset,
unranked_code)
def next_gray(self):
"""
Generates the next Gray code ordered subset.
Examples
========
>>> from sympy.combinatorics import Subset
>>> a = Subset([1, 2, 3], [1, 2, 3, 4])
>>> a.next_gray().subset
[1, 3]
See Also
========
iterate_graycode, prev_gray
"""
return self.iterate_graycode(1)
def prev_gray(self):
"""
Generates the previous Gray code ordered subset.
Examples
========
>>> from sympy.combinatorics import Subset
>>> a = Subset([2, 3, 4], [1, 2, 3, 4, 5])
>>> a.prev_gray().subset
[2, 3, 4, 5]
See Also
========
iterate_graycode, next_gray
"""
return self.iterate_graycode(-1)
@property
def rank_binary(self):
"""
Computes the binary ordered rank.
Examples
========
>>> from sympy.combinatorics import Subset
>>> a = Subset([], ['a','b','c','d'])
>>> a.rank_binary
0
>>> a = Subset(['c', 'd'], ['a', 'b', 'c', 'd'])
>>> a.rank_binary
3
See Also
========
iterate_binary, unrank_binary
"""
if self._rank_binary is None:
self._rank_binary = int("".join(
Subset.bitlist_from_subset(self.subset,
self.superset)), 2)
return self._rank_binary
@property
def rank_lexicographic(self):
"""
Computes the lexicographic ranking of the subset.
Examples
========
>>> from sympy.combinatorics import Subset
>>> a = Subset(['c', 'd'], ['a', 'b', 'c', 'd'])
>>> a.rank_lexicographic
14
>>> a = Subset([2, 4, 5], [1, 2, 3, 4, 5, 6])
>>> a.rank_lexicographic
43
"""
if self._rank_lex is None:
def _ranklex(self, subset_index, i, n):
if subset_index == [] or i > n:
return 0
if i in subset_index:
subset_index.remove(i)
return 1 + _ranklex(self, subset_index, i + 1, n)
return 2**(n - i - 1) + _ranklex(self, subset_index, i + 1, n)
indices = Subset.subset_indices(self.subset, self.superset)
self._rank_lex = _ranklex(self, indices, 0, self.superset_size)
return self._rank_lex
@property
def rank_gray(self):
"""
Computes the Gray code ranking of the subset.
Examples
========
>>> from sympy.combinatorics import Subset
>>> a = Subset(['c','d'], ['a','b','c','d'])
>>> a.rank_gray
2
>>> a = Subset([2, 4, 5], [1, 2, 3, 4, 5, 6])
>>> a.rank_gray
27
See Also
========
iterate_graycode, unrank_gray
"""
if self._rank_graycode is None:
bits = Subset.bitlist_from_subset(self.subset, self.superset)
self._rank_graycode = GrayCode(len(bits), start=bits).rank
return self._rank_graycode
@property
def subset(self):
"""
Gets the subset represented by the current instance.
Examples
========
>>> from sympy.combinatorics import Subset
>>> a = Subset(['c', 'd'], ['a', 'b', 'c', 'd'])
>>> a.subset
['c', 'd']
See Also
========
superset, size, superset_size, cardinality
"""
return self._subset
@property
def size(self):
"""
Gets the size of the subset.
Examples
========
>>> from sympy.combinatorics import Subset
>>> a = Subset(['c', 'd'], ['a', 'b', 'c', 'd'])
>>> a.size
2
See Also
========
subset, superset, superset_size, cardinality
"""
return len(self.subset)
@property
def superset(self):
"""
Gets the superset of the subset.
Examples
========
>>> from sympy.combinatorics import Subset
>>> a = Subset(['c', 'd'], ['a', 'b', 'c', 'd'])
>>> a.superset
['a', 'b', 'c', 'd']
See Also
========
subset, size, superset_size, cardinality
"""
return self._superset
@property
def superset_size(self):
"""
Returns the size of the superset.
Examples
========
>>> from sympy.combinatorics import Subset
>>> a = Subset(['c', 'd'], ['a', 'b', 'c', 'd'])
>>> a.superset_size
4
See Also
========
subset, superset, size, cardinality
"""
return len(self.superset)
@property
def cardinality(self):
"""
Returns the number of all possible subsets.
Examples
========
>>> from sympy.combinatorics import Subset
>>> a = Subset(['c', 'd'], ['a', 'b', 'c', 'd'])
>>> a.cardinality
16
See Also
========
subset, superset, size, superset_size
"""
return 2**(self.superset_size)
@classmethod
def subset_from_bitlist(self, super_set, bitlist):
"""
Gets the subset defined by the bitlist.
Examples
========
>>> from sympy.combinatorics import Subset
>>> Subset.subset_from_bitlist(['a', 'b', 'c', 'd'], '0011').subset
['c', 'd']
See Also
========
bitlist_from_subset
"""
if len(super_set) != len(bitlist):
raise ValueError("The sizes of the lists are not equal")
ret_set = []
for i in range(len(bitlist)):
if bitlist[i] == '1':
ret_set.append(super_set[i])
return Subset(ret_set, super_set)
@classmethod
def bitlist_from_subset(self, subset, superset):
"""
Gets the bitlist corresponding to a subset.
Examples
========
>>> from sympy.combinatorics import Subset
>>> Subset.bitlist_from_subset(['c', 'd'], ['a', 'b', 'c', 'd'])
'0011'
See Also
========
subset_from_bitlist
"""
bitlist = ['0'] * len(superset)
if isinstance(subset, Subset):
subset = subset.subset
for i in Subset.subset_indices(subset, superset):
bitlist[i] = '1'
return ''.join(bitlist)
@classmethod
def unrank_binary(self, rank, superset):
"""
Gets the binary ordered subset of the specified rank.
Examples
========
>>> from sympy.combinatorics import Subset
>>> Subset.unrank_binary(4, ['a', 'b', 'c', 'd']).subset
['b']
See Also
========
iterate_binary, rank_binary
"""
bits = bin(rank)[2:].rjust(len(superset), '0')
return Subset.subset_from_bitlist(superset, bits)
@classmethod
def unrank_gray(self, rank, superset):
"""
Gets the Gray code ordered subset of the specified rank.
Examples
========
>>> from sympy.combinatorics import Subset
>>> Subset.unrank_gray(4, ['a', 'b', 'c']).subset
['a', 'b']
>>> Subset.unrank_gray(0, ['a', 'b', 'c']).subset
[]
See Also
========
iterate_graycode, rank_gray
"""
graycode_bitlist = GrayCode.unrank(len(superset), rank)
return Subset.subset_from_bitlist(superset, graycode_bitlist)
@classmethod
def subset_indices(self, subset, superset):
"""Return indices of subset in superset in a list; the list is empty
if all elements of ``subset`` are not in ``superset``.
Examples
========
>>> from sympy.combinatorics import Subset
>>> superset = [1, 3, 2, 5, 4]
>>> Subset.subset_indices([3, 2, 1], superset)
[1, 2, 0]
>>> Subset.subset_indices([1, 6], superset)
[]
>>> Subset.subset_indices([], superset)
[]
"""
a, b = superset, subset
sb = set(b)
d = {}
for i, ai in enumerate(a):
if ai in sb:
d[ai] = i
sb.remove(ai)
if not sb:
break
else:
return []
return [d[bi] for bi in b]
def ksubsets(superset, k):
"""
Finds the subsets of size ``k`` in lexicographic order.
This uses the itertools generator.
Examples
========
>>> from sympy.combinatorics.subsets import ksubsets
>>> list(ksubsets([1, 2, 3], 2))
[(1, 2), (1, 3), (2, 3)]
>>> list(ksubsets([1, 2, 3, 4, 5], 2))
[(1, 2), (1, 3), (1, 4), (1, 5), (2, 3), (2, 4), \
(2, 5), (3, 4), (3, 5), (4, 5)]
See Also
========
Subset
"""
return combinations(superset, k)
PK ]ZZZ�E �4� 4� ! sympy/combinatorics/tensor_can.pyfrom sympy.combinatorics.permutations import Permutation, _af_rmul, \
_af_invert, _af_new
from sympy.combinatorics.perm_groups import PermutationGroup, _orbit, \
_orbit_transversal
from sympy.combinatorics.util import _distribute_gens_by_base, \
_orbits_transversals_from_bsgs
"""
References for tensor canonicalization:
[1] R. Portugal "Algorithmic simplification of tensor expressions",
J. Phys. A 32 (1999) 7779-7789
[2] R. Portugal, B.F. Svaiter "Group-theoretic Approach for Symbolic
Tensor Manipulation: I. Free Indices"
arXiv:math-ph/0107031v1
[3] L.R.U. Manssur, R. Portugal "Group-theoretic Approach for Symbolic
Tensor Manipulation: II. Dummy Indices"
arXiv:math-ph/0107032v1
[4] xperm.c part of XPerm written by J. M. Martin-Garcia
http://www.xact.es/index.html
"""
def dummy_sgs(dummies, sym, n):
"""
Return the strong generators for dummy indices.
Parameters
==========
dummies : List of dummy indices.
`dummies[2k], dummies[2k+1]` are paired indices.
In base form, the dummy indices are always in
consecutive positions.
sym : symmetry under interchange of contracted dummies::
* None no symmetry
* 0 commuting
* 1 anticommuting
n : number of indices
Examples
========
>>> from sympy.combinatorics.tensor_can import dummy_sgs
>>> dummy_sgs(list(range(2, 8)), 0, 8)
[[0, 1, 3, 2, 4, 5, 6, 7, 8, 9], [0, 1, 2, 3, 5, 4, 6, 7, 8, 9],
[0, 1, 2, 3, 4, 5, 7, 6, 8, 9], [0, 1, 4, 5, 2, 3, 6, 7, 8, 9],
[0, 1, 2, 3, 6, 7, 4, 5, 8, 9]]
"""
if len(dummies) > n:
raise ValueError("List too large")
res = []
# exchange of contravariant and covariant indices
if sym is not None:
for j in dummies[::2]:
a = list(range(n + 2))
if sym == 1:
a[n] = n + 1
a[n + 1] = n
a[j], a[j + 1] = a[j + 1], a[j]
res.append(a)
# rename dummy indices
for j in dummies[:-3:2]:
a = list(range(n + 2))
a[j:j + 4] = a[j + 2], a[j + 3], a[j], a[j + 1]
res.append(a)
return res
def _min_dummies(dummies, sym, indices):
"""
Return list of minima of the orbits of indices in group of dummies.
See ``double_coset_can_rep`` for the description of ``dummies`` and ``sym``.
``indices`` is the initial list of dummy indices.
Examples
========
>>> from sympy.combinatorics.tensor_can import _min_dummies
>>> _min_dummies([list(range(2, 8))], [0], list(range(10)))
[0, 1, 2, 2, 2, 2, 2, 2, 8, 9]
"""
num_types = len(sym)
m = [min(dx) if dx else None for dx in dummies]
res = indices[:]
for i in range(num_types):
for c, i in enumerate(indices):
for j in range(num_types):
if i in dummies[j]:
res[c] = m[j]
break
return res
def _trace_S(s, j, b, S_cosets):
"""
Return the representative h satisfying s[h[b]] == j
If there is not such a representative return None
"""
for h in S_cosets[b]:
if s[h[b]] == j:
return h
return None
def _trace_D(gj, p_i, Dxtrav):
"""
Return the representative h satisfying h[gj] == p_i
If there is not such a representative return None
"""
for h in Dxtrav:
if h[gj] == p_i:
return h
return None
def _dumx_remove(dumx, dumx_flat, p0):
"""
remove p0 from dumx
"""
res = []
for dx in dumx:
if p0 not in dx:
res.append(dx)
continue
k = dx.index(p0)
if k % 2 == 0:
p0_paired = dx[k + 1]
else:
p0_paired = dx[k - 1]
dx.remove(p0)
dx.remove(p0_paired)
dumx_flat.remove(p0)
dumx_flat.remove(p0_paired)
res.append(dx)
def transversal2coset(size, base, transversal):
a = []
j = 0
for i in range(size):
if i in base:
a.append(sorted(transversal[j].values()))
j += 1
else:
a.append([list(range(size))])
j = len(a) - 1
while a[j] == [list(range(size))]:
j -= 1
return a[:j + 1]
def double_coset_can_rep(dummies, sym, b_S, sgens, S_transversals, g):
r"""
Butler-Portugal algorithm for tensor canonicalization with dummy indices.
Parameters
==========
dummies
list of lists of dummy indices,
one list for each type of index;
the dummy indices are put in order contravariant, covariant
[d0, -d0, d1, -d1, ...].
sym
list of the symmetries of the index metric for each type.
possible symmetries of the metrics
* 0 symmetric
* 1 antisymmetric
* None no symmetry
b_S
base of a minimal slot symmetry BSGS.
sgens
generators of the slot symmetry BSGS.
S_transversals
transversals for the slot BSGS.
g
permutation representing the tensor.
Returns
=======
Return 0 if the tensor is zero, else return the array form of
the permutation representing the canonical form of the tensor.
Notes
=====
A tensor with dummy indices can be represented in a number
of equivalent ways which typically grows exponentially with
the number of indices. To be able to establish if two tensors
with many indices are equal becomes computationally very slow
in absence of an efficient algorithm.
The Butler-Portugal algorithm [3] is an efficient algorithm to
put tensors in canonical form, solving the above problem.
Portugal observed that a tensor can be represented by a permutation,
and that the class of tensors equivalent to it under slot and dummy
symmetries is equivalent to the double coset `D*g*S`
(Note: in this documentation we use the conventions for multiplication
of permutations p, q with (p*q)(i) = p[q[i]] which is opposite
to the one used in the Permutation class)
Using the algorithm by Butler to find a representative of the
double coset one can find a canonical form for the tensor.
To see this correspondence,
let `g` be a permutation in array form; a tensor with indices `ind`
(the indices including both the contravariant and the covariant ones)
can be written as
`t = T(ind[g[0]], \dots, ind[g[n-1]])`,
where `n = len(ind)`;
`g` has size `n + 2`, the last two indices for the sign of the tensor
(trick introduced in [4]).
A slot symmetry transformation `s` is a permutation acting on the slots
`t \rightarrow T(ind[(g*s)[0]], \dots, ind[(g*s)[n-1]])`
A dummy symmetry transformation acts on `ind`
`t \rightarrow T(ind[(d*g)[0]], \dots, ind[(d*g)[n-1]])`
Being interested only in the transformations of the tensor under
these symmetries, one can represent the tensor by `g`, which transforms
as
`g -> d*g*s`, so it belongs to the coset `D*g*S`, or in other words
to the set of all permutations allowed by the slot and dummy symmetries.
Let us explain the conventions by an example.
Given a tensor `T^{d3 d2 d1}{}_{d1 d2 d3}` with the slot symmetries
`T^{a0 a1 a2 a3 a4 a5} = -T^{a2 a1 a0 a3 a4 a5}`
`T^{a0 a1 a2 a3 a4 a5} = -T^{a4 a1 a2 a3 a0 a5}`
and symmetric metric, find the tensor equivalent to it which
is the lowest under the ordering of indices:
lexicographic ordering `d1, d2, d3` and then contravariant
before covariant index; that is the canonical form of the tensor.
The canonical form is `-T^{d1 d2 d3}{}_{d1 d2 d3}`
obtained using `T^{a0 a1 a2 a3 a4 a5} = -T^{a2 a1 a0 a3 a4 a5}`.
To convert this problem in the input for this function,
use the following ordering of the index names
(- for covariant for short) `d1, -d1, d2, -d2, d3, -d3`
`T^{d3 d2 d1}{}_{d1 d2 d3}` corresponds to `g = [4, 2, 0, 1, 3, 5, 6, 7]`
where the last two indices are for the sign
`sgens = [Permutation(0, 2)(6, 7), Permutation(0, 4)(6, 7)]`
sgens[0] is the slot symmetry `-(0, 2)`
`T^{a0 a1 a2 a3 a4 a5} = -T^{a2 a1 a0 a3 a4 a5}`
sgens[1] is the slot symmetry `-(0, 4)`
`T^{a0 a1 a2 a3 a4 a5} = -T^{a4 a1 a2 a3 a0 a5}`
The dummy symmetry group D is generated by the strong base generators
`[(0, 1), (2, 3), (4, 5), (0, 2)(1, 3), (0, 4)(1, 5)]`
where the first three interchange covariant and contravariant
positions of the same index (d1 <-> -d1) and the last two interchange
the dummy indices themselves (d1 <-> d2).
The dummy symmetry acts from the left
`d = [1, 0, 2, 3, 4, 5, 6, 7]` exchange `d1 \leftrightarrow -d1`
`T^{d3 d2 d1}{}_{d1 d2 d3} == T^{d3 d2}{}_{d1}{}^{d1}{}_{d2 d3}`
`g=[4, 2, 0, 1, 3, 5, 6, 7] -> [4, 2, 1, 0, 3, 5, 6, 7] = _af_rmul(d, g)`
which differs from `_af_rmul(g, d)`.
The slot symmetry acts from the right
`s = [2, 1, 0, 3, 4, 5, 7, 6]` exchanges slots 0 and 2 and changes sign
`T^{d3 d2 d1}{}_{d1 d2 d3} == -T^{d1 d2 d3}{}_{d1 d2 d3}`
`g=[4,2,0,1,3,5,6,7] -> [0, 2, 4, 1, 3, 5, 7, 6] = _af_rmul(g, s)`
Example in which the tensor is zero, same slot symmetries as above:
`T^{d2}{}_{d1 d3}{}^{d1 d3}{}_{d2}`
`= -T^{d3}{}_{d1 d3}{}^{d1 d2}{}_{d2}` under slot symmetry `-(0,4)`;
`= T_{d3 d1}{}^{d3}{}^{d1 d2}{}_{d2}` under slot symmetry `-(0,2)`;
`= T^{d3}{}_{d1 d3}{}^{d1 d2}{}_{d2}` symmetric metric;
`= 0` since two of these lines have tensors differ only for the sign.
The double coset D*g*S consists of permutations `h = d*g*s` corresponding
to equivalent tensors; if there are two `h` which are the same apart
from the sign, return zero; otherwise
choose as representative the tensor with indices
ordered lexicographically according to `[d1, -d1, d2, -d2, d3, -d3]`
that is ``rep = min(D*g*S) = min([d*g*s for d in D for s in S])``
The indices are fixed one by one; first choose the lowest index
for slot 0, then the lowest remaining index for slot 1, etc.
Doing this one obtains a chain of stabilizers
`S \rightarrow S_{b0} \rightarrow S_{b0,b1} \rightarrow \dots` and
`D \rightarrow D_{p0} \rightarrow D_{p0,p1} \rightarrow \dots`
where ``[b0, b1, ...] = range(b)`` is a base of the symmetric group;
the strong base `b_S` of S is an ordered sublist of it;
therefore it is sufficient to compute once the
strong base generators of S using the Schreier-Sims algorithm;
the stabilizers of the strong base generators are the
strong base generators of the stabilizer subgroup.
``dbase = [p0, p1, ...]`` is not in general in lexicographic order,
so that one must recompute the strong base generators each time;
however this is trivial, there is no need to use the Schreier-Sims
algorithm for D.
The algorithm keeps a TAB of elements `(s_i, d_i, h_i)`
where `h_i = d_i \times g \times s_i` satisfying `h_i[j] = p_j` for `0 \le j < i`
starting from `s_0 = id, d_0 = id, h_0 = g`.
The equations `h_0[0] = p_0, h_1[1] = p_1, \dots` are solved in this order,
choosing each time the lowest possible value of p_i
For `j < i`
`d_i*g*s_i*S_{b_0, \dots, b_{i-1}}*b_j = D_{p_0, \dots, p_{i-1}}*p_j`
so that for dx in `D_{p_0,\dots,p_{i-1}}` and sx in
`S_{base[0], \dots, base[i-1]}` one has `dx*d_i*g*s_i*sx*b_j = p_j`
Search for dx, sx such that this equation holds for `j = i`;
it can be written as `s_i*sx*b_j = J, dx*d_i*g*J = p_j`
`sx*b_j = s_i**-1*J; sx = trace(s_i**-1, S_{b_0,...,b_{i-1}})`
`dx**-1*p_j = d_i*g*J; dx = trace(d_i*g*J, D_{p_0,...,p_{i-1}})`
`s_{i+1} = s_i*trace(s_i**-1*J, S_{b_0,...,b_{i-1}})`
`d_{i+1} = trace(d_i*g*J, D_{p_0,...,p_{i-1}})**-1*d_i`
`h_{i+1}*b_i = d_{i+1}*g*s_{i+1}*b_i = p_i`
`h_n*b_j = p_j` for all j, so that `h_n` is the solution.
Add the found `(s, d, h)` to TAB1.
At the end of the iteration sort TAB1 with respect to the `h`;
if there are two consecutive `h` in TAB1 which differ only for the
sign, the tensor is zero, so return 0;
if there are two consecutive `h` which are equal, keep only one.
Then stabilize the slot generators under `i` and the dummy generators
under `p_i`.
Assign `TAB = TAB1` at the end of the iteration step.
At the end `TAB` contains a unique `(s, d, h)`, since all the slots
of the tensor `h` have been fixed to have the minimum value according
to the symmetries. The algorithm returns `h`.
It is important that the slot BSGS has lexicographic minimal base,
otherwise there is an `i` which does not belong to the slot base
for which `p_i` is fixed by the dummy symmetry only, while `i`
is not invariant from the slot stabilizer, so `p_i` is not in
general the minimal value.
This algorithm differs slightly from the original algorithm [3]:
the canonical form is minimal lexicographically, and
the BSGS has minimal base under lexicographic order.
Equal tensors `h` are eliminated from TAB.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> from sympy.combinatorics.tensor_can import double_coset_can_rep, get_transversals
>>> gens = [Permutation(x) for x in [[2, 1, 0, 3, 4, 5, 7, 6], [4, 1, 2, 3, 0, 5, 7, 6]]]
>>> base = [0, 2]
>>> g = Permutation([4, 2, 0, 1, 3, 5, 6, 7])
>>> transversals = get_transversals(base, gens)
>>> double_coset_can_rep([list(range(6))], [0], base, gens, transversals, g)
[0, 1, 2, 3, 4, 5, 7, 6]
>>> g = Permutation([4, 1, 3, 0, 5, 2, 6, 7])
>>> double_coset_can_rep([list(range(6))], [0], base, gens, transversals, g)
0
"""
size = g.size
g = g.array_form
num_dummies = size - 2
indices = list(range(num_dummies))
all_metrics_with_sym = not any(_ is None for _ in sym)
num_types = len(sym)
dumx = dummies[:]
dumx_flat = []
for dx in dumx:
dumx_flat.extend(dx)
b_S = b_S[:]
sgensx = [h._array_form for h in sgens]
if b_S:
S_transversals = transversal2coset(size, b_S, S_transversals)
# strong generating set for D
dsgsx = []
for i in range(num_types):
dsgsx.extend(dummy_sgs(dumx[i], sym[i], num_dummies))
idn = list(range(size))
# TAB = list of entries (s, d, h) where h = _af_rmuln(d,g,s)
# for short, in the following d*g*s means _af_rmuln(d,g,s)
TAB = [(idn, idn, g)]
for i in range(size - 2):
b = i
testb = b in b_S and sgensx
if testb:
sgensx1 = [_af_new(_) for _ in sgensx]
deltab = _orbit(size, sgensx1, b)
else:
deltab = {b}
# p1 = min(IMAGES) = min(Union D_p*h*deltab for h in TAB)
if all_metrics_with_sym:
md = _min_dummies(dumx, sym, indices)
else:
md = [min(_orbit(size, [_af_new(
ddx) for ddx in dsgsx], ii)) for ii in range(size - 2)]
p_i = min(min(md[h[x]] for x in deltab) for s, d, h in TAB)
dsgsx1 = [_af_new(_) for _ in dsgsx]
Dxtrav = _orbit_transversal(size, dsgsx1, p_i, False, af=True) \
if dsgsx else None
if Dxtrav:
Dxtrav = [_af_invert(x) for x in Dxtrav]
# compute the orbit of p_i
for ii in range(num_types):
if p_i in dumx[ii]:
# the orbit is made by all the indices in dum[ii]
if sym[ii] is not None:
deltap = dumx[ii]
else:
# the orbit is made by all the even indices if p_i
# is even, by all the odd indices if p_i is odd
p_i_index = dumx[ii].index(p_i) % 2
deltap = dumx[ii][p_i_index::2]
break
else:
deltap = [p_i]
TAB1 = []
while TAB:
s, d, h = TAB.pop()
if min(md[h[x]] for x in deltab) != p_i:
continue
deltab1 = [x for x in deltab if md[h[x]] == p_i]
# NEXT = s*deltab1 intersection (d*g)**-1*deltap
dg = _af_rmul(d, g)
dginv = _af_invert(dg)
sdeltab = [s[x] for x in deltab1]
gdeltap = [dginv[x] for x in deltap]
NEXT = [x for x in sdeltab if x in gdeltap]
# d, s satisfy
# d*g*s*base[i-1] = p_{i-1}; using the stabilizers
# d*g*s*S_{base[0],...,base[i-1]}*base[i-1] =
# D_{p_0,...,p_{i-1}}*p_{i-1}
# so that to find d1, s1 satisfying d1*g*s1*b = p_i
# one can look for dx in D_{p_0,...,p_{i-1}} and
# sx in S_{base[0],...,base[i-1]}
# d1 = dx*d; s1 = s*sx
# d1*g*s1*b = dx*d*g*s*sx*b = p_i
for j in NEXT:
if testb:
# solve s1*b = j with s1 = s*sx for some element sx
# of the stabilizer of ..., base[i-1]
# sx*b = s**-1*j; sx = _trace_S(s, j,...)
# s1 = s*trace_S(s**-1*j,...)
s1 = _trace_S(s, j, b, S_transversals)
if not s1:
continue
else:
s1 = [s[ix] for ix in s1]
else:
s1 = s
# assert s1[b] == j # invariant
# solve d1*g*j = p_i with d1 = dx*d for some element dg
# of the stabilizer of ..., p_{i-1}
# dx**-1*p_i = d*g*j; dx**-1 = trace_D(d*g*j,...)
# d1 = trace_D(d*g*j,...)**-1*d
# to save an inversion in the inner loop; notice we did
# Dxtrav = [perm_af_invert(x) for x in Dxtrav] out of the loop
if Dxtrav:
d1 = _trace_D(dg[j], p_i, Dxtrav)
if not d1:
continue
else:
if p_i != dg[j]:
continue
d1 = idn
assert d1[dg[j]] == p_i # invariant
d1 = [d1[ix] for ix in d]
h1 = [d1[g[ix]] for ix in s1]
# assert h1[b] == p_i # invariant
TAB1.append((s1, d1, h1))
# if TAB contains equal permutations, keep only one of them;
# if TAB contains equal permutations up to the sign, return 0
TAB1.sort(key=lambda x: x[-1])
prev = [0] * size
while TAB1:
s, d, h = TAB1.pop()
if h[:-2] == prev[:-2]:
if h[-1] != prev[-1]:
return 0
else:
TAB.append((s, d, h))
prev = h
# stabilize the SGS
sgensx = [h for h in sgensx if h[b] == b]
if b in b_S:
b_S.remove(b)
_dumx_remove(dumx, dumx_flat, p_i)
dsgsx = []
for i in range(num_types):
dsgsx.extend(dummy_sgs(dumx[i], sym[i], num_dummies))
return TAB[0][-1]
def canonical_free(base, gens, g, num_free):
"""
Canonicalization of a tensor with respect to free indices
choosing the minimum with respect to lexicographical ordering
in the free indices.
Explanation
===========
``base``, ``gens`` BSGS for slot permutation group
``g`` permutation representing the tensor
``num_free`` number of free indices
The indices must be ordered with first the free indices
See explanation in double_coset_can_rep
The algorithm is a variation of the one given in [2].
Examples
========
>>> from sympy.combinatorics import Permutation
>>> from sympy.combinatorics.tensor_can import canonical_free
>>> gens = [[1, 0, 2, 3, 5, 4], [2, 3, 0, 1, 4, 5],[0, 1, 3, 2, 5, 4]]
>>> gens = [Permutation(h) for h in gens]
>>> base = [0, 2]
>>> g = Permutation([2, 1, 0, 3, 4, 5])
>>> canonical_free(base, gens, g, 4)
[0, 3, 1, 2, 5, 4]
Consider the product of Riemann tensors
``T = R^{a}_{d0}^{d1,d2}*R_{d2,d1}^{d0,b}``
The order of the indices is ``[a, b, d0, -d0, d1, -d1, d2, -d2]``
The permutation corresponding to the tensor is
``g = [0, 3, 4, 6, 7, 5, 2, 1, 8, 9]``
In particular ``a`` is position ``0``, ``b`` is in position ``9``.
Use the slot symmetries to get `T` is a form which is the minimal
in lexicographic order in the free indices ``a`` and ``b``, e.g.
``-R^{a}_{d0}^{d1,d2}*R^{b,d0}_{d2,d1}`` corresponding to
``[0, 3, 4, 6, 1, 2, 7, 5, 9, 8]``
>>> from sympy.combinatorics.tensor_can import riemann_bsgs, tensor_gens
>>> base, gens = riemann_bsgs
>>> size, sbase, sgens = tensor_gens(base, gens, [[], []], 0)
>>> g = Permutation([0, 3, 4, 6, 7, 5, 2, 1, 8, 9])
>>> canonical_free(sbase, [Permutation(h) for h in sgens], g, 2)
[0, 3, 4, 6, 1, 2, 7, 5, 9, 8]
"""
g = g.array_form
size = len(g)
if not base:
return g[:]
transversals = get_transversals(base, gens)
for x in sorted(g[:-2]):
if x not in base:
base.append(x)
h = g
for transv in transversals:
h_i = [size]*num_free
# find the element s in transversals[i] such that
# _af_rmul(h, s) has its free elements with the lowest position in h
s = None
for sk in transv.values():
h1 = _af_rmul(h, sk)
hi = [h1.index(ix) for ix in range(num_free)]
if hi < h_i:
h_i = hi
s = sk
if s:
h = _af_rmul(h, s)
return h
def _get_map_slots(size, fixed_slots):
res = list(range(size))
pos = 0
for i in range(size):
if i in fixed_slots:
continue
res[i] = pos
pos += 1
return res
def _lift_sgens(size, fixed_slots, free, s):
a = []
j = k = 0
fd = list(zip(fixed_slots, free))
fd = [y for x, y in sorted(fd)]
num_free = len(free)
for i in range(size):
if i in fixed_slots:
a.append(fd[k])
k += 1
else:
a.append(s[j] + num_free)
j += 1
return a
def canonicalize(g, dummies, msym, *v):
"""
canonicalize tensor formed by tensors
Parameters
==========
g : permutation representing the tensor
dummies : list representing the dummy indices
it can be a list of dummy indices of the same type
or a list of lists of dummy indices, one list for each
type of index;
the dummy indices must come after the free indices,
and put in order contravariant, covariant
[d0, -d0, d1,-d1,...]
msym : symmetry of the metric(s)
it can be an integer or a list;
in the first case it is the symmetry of the dummy index metric;
in the second case it is the list of the symmetries of the
index metric for each type
v : list, (base_i, gens_i, n_i, sym_i) for tensors of type `i`
base_i, gens_i : BSGS for tensors of this type.
The BSGS should have minimal base under lexicographic ordering;
if not, an attempt is made do get the minimal BSGS;
in case of failure,
canonicalize_naive is used, which is much slower.
n_i : number of tensors of type `i`.
sym_i : symmetry under exchange of component tensors of type `i`.
Both for msym and sym_i the cases are
* None no symmetry
* 0 commuting
* 1 anticommuting
Returns
=======
0 if the tensor is zero, else return the array form of
the permutation representing the canonical form of the tensor.
Algorithm
=========
First one uses canonical_free to get the minimum tensor under
lexicographic order, using only the slot symmetries.
If the component tensors have not minimal BSGS, it is attempted
to find it; if the attempt fails canonicalize_naive
is used instead.
Compute the residual slot symmetry keeping fixed the free indices
using tensor_gens(base, gens, list_free_indices, sym).
Reduce the problem eliminating the free indices.
Then use double_coset_can_rep and lift back the result reintroducing
the free indices.
Examples
========
one type of index with commuting metric;
`A_{a b}` and `B_{a b}` antisymmetric and commuting
`T = A_{d0 d1} * B^{d0}{}_{d2} * B^{d2 d1}`
`ord = [d0,-d0,d1,-d1,d2,-d2]` order of the indices
g = [1, 3, 0, 5, 4, 2, 6, 7]
`T_c = 0`
>>> from sympy.combinatorics.tensor_can import get_symmetric_group_sgs, canonicalize, bsgs_direct_product
>>> from sympy.combinatorics import Permutation
>>> base2a, gens2a = get_symmetric_group_sgs(2, 1)
>>> t0 = (base2a, gens2a, 1, 0)
>>> t1 = (base2a, gens2a, 2, 0)
>>> g = Permutation([1, 3, 0, 5, 4, 2, 6, 7])
>>> canonicalize(g, range(6), 0, t0, t1)
0
same as above, but with `B_{a b}` anticommuting
`T_c = -A^{d0 d1} * B_{d0}{}^{d2} * B_{d1 d2}`
can = [0,2,1,4,3,5,7,6]
>>> t1 = (base2a, gens2a, 2, 1)
>>> canonicalize(g, range(6), 0, t0, t1)
[0, 2, 1, 4, 3, 5, 7, 6]
two types of indices `[a,b,c,d,e,f]` and `[m,n]`, in this order,
both with commuting metric
`f^{a b c}` antisymmetric, commuting
`A_{m a}` no symmetry, commuting
`T = f^c{}_{d a} * f^f{}_{e b} * A_m{}^d * A^{m b} * A_n{}^a * A^{n e}`
ord = [c,f,a,-a,b,-b,d,-d,e,-e,m,-m,n,-n]
g = [0,7,3, 1,9,5, 11,6, 10,4, 13,2, 12,8, 14,15]
The canonical tensor is
`T_c = -f^{c a b} * f^{f d e} * A^m{}_a * A_{m d} * A^n{}_b * A_{n e}`
can = [0,2,4, 1,6,8, 10,3, 11,7, 12,5, 13,9, 15,14]
>>> base_f, gens_f = get_symmetric_group_sgs(3, 1)
>>> base1, gens1 = get_symmetric_group_sgs(1)
>>> base_A, gens_A = bsgs_direct_product(base1, gens1, base1, gens1)
>>> t0 = (base_f, gens_f, 2, 0)
>>> t1 = (base_A, gens_A, 4, 0)
>>> dummies = [range(2, 10), range(10, 14)]
>>> g = Permutation([0, 7, 3, 1, 9, 5, 11, 6, 10, 4, 13, 2, 12, 8, 14, 15])
>>> canonicalize(g, dummies, [0, 0], t0, t1)
[0, 2, 4, 1, 6, 8, 10, 3, 11, 7, 12, 5, 13, 9, 15, 14]
"""
from sympy.combinatorics.testutil import canonicalize_naive
if not isinstance(msym, list):
if msym not in (0, 1, None):
raise ValueError('msym must be 0, 1 or None')
num_types = 1
else:
num_types = len(msym)
if not all(msymx in (0, 1, None) for msymx in msym):
raise ValueError('msym entries must be 0, 1 or None')
if len(dummies) != num_types:
raise ValueError(
'dummies and msym must have the same number of elements')
size = g.size
num_tensors = 0
v1 = []
for base_i, gens_i, n_i, sym_i in v:
# check that the BSGS is minimal;
# this property is used in double_coset_can_rep;
# if it is not minimal use canonicalize_naive
if not _is_minimal_bsgs(base_i, gens_i):
mbsgs = get_minimal_bsgs(base_i, gens_i)
if not mbsgs:
can = canonicalize_naive(g, dummies, msym, *v)
return can
base_i, gens_i = mbsgs
v1.append((base_i, gens_i, [[]] * n_i, sym_i))
num_tensors += n_i
if num_types == 1 and not isinstance(msym, list):
dummies = [dummies]
msym = [msym]
flat_dummies = []
for dumx in dummies:
flat_dummies.extend(dumx)
if flat_dummies and flat_dummies != list(range(flat_dummies[0], flat_dummies[-1] + 1)):
raise ValueError('dummies is not valid')
# slot symmetry of the tensor
size1, sbase, sgens = gens_products(*v1)
if size != size1:
raise ValueError(
'g has size %d, generators have size %d' % (size, size1))
free = [i for i in range(size - 2) if i not in flat_dummies]
num_free = len(free)
# g1 minimal tensor under slot symmetry
g1 = canonical_free(sbase, sgens, g, num_free)
if not flat_dummies:
return g1
# save the sign of g1
sign = 0 if g1[-1] == size - 1 else 1
# the free indices are kept fixed.
# Determine free_i, the list of slots of tensors which are fixed
# since they are occupied by free indices, which are fixed.
start = 0
for i, (base_i, gens_i, n_i, sym_i) in enumerate(v):
free_i = []
len_tens = gens_i[0].size - 2
# for each component tensor get a list od fixed islots
for j in range(n_i):
# get the elements corresponding to the component tensor
h = g1[start:(start + len_tens)]
fr = []
# get the positions of the fixed elements in h
for k in free:
if k in h:
fr.append(h.index(k))
free_i.append(fr)
start += len_tens
v1[i] = (base_i, gens_i, free_i, sym_i)
# BSGS of the tensor with fixed free indices
# if tensor_gens fails in gens_product, use canonicalize_naive
size, sbase, sgens = gens_products(*v1)
# reduce the permutations getting rid of the free indices
pos_free = [g1.index(x) for x in range(num_free)]
size_red = size - num_free
g1_red = [x - num_free for x in g1 if x in flat_dummies]
if sign:
g1_red.extend([size_red - 1, size_red - 2])
else:
g1_red.extend([size_red - 2, size_red - 1])
map_slots = _get_map_slots(size, pos_free)
sbase_red = [map_slots[i] for i in sbase if i not in pos_free]
sgens_red = [_af_new([map_slots[i] for i in y._array_form if i not in pos_free]) for y in sgens]
dummies_red = [[x - num_free for x in y] for y in dummies]
transv_red = get_transversals(sbase_red, sgens_red)
g1_red = _af_new(g1_red)
g2 = double_coset_can_rep(
dummies_red, msym, sbase_red, sgens_red, transv_red, g1_red)
if g2 == 0:
return 0
# lift to the case with the free indices
g3 = _lift_sgens(size, pos_free, free, g2)
return g3
def perm_af_direct_product(gens1, gens2, signed=True):
"""
Direct products of the generators gens1 and gens2.
Examples
========
>>> from sympy.combinatorics.tensor_can import perm_af_direct_product
>>> gens1 = [[1, 0, 2, 3], [0, 1, 3, 2]]
>>> gens2 = [[1, 0]]
>>> perm_af_direct_product(gens1, gens2, False)
[[1, 0, 2, 3, 4, 5], [0, 1, 3, 2, 4, 5], [0, 1, 2, 3, 5, 4]]
>>> gens1 = [[1, 0, 2, 3, 5, 4], [0, 1, 3, 2, 4, 5]]
>>> gens2 = [[1, 0, 2, 3]]
>>> perm_af_direct_product(gens1, gens2, True)
[[1, 0, 2, 3, 4, 5, 7, 6], [0, 1, 3, 2, 4, 5, 6, 7], [0, 1, 2, 3, 5, 4, 6, 7]]
"""
gens1 = [list(x) for x in gens1]
gens2 = [list(x) for x in gens2]
s = 2 if signed else 0
n1 = len(gens1[0]) - s
n2 = len(gens2[0]) - s
start = list(range(n1))
end = list(range(n1, n1 + n2))
if signed:
gens1 = [gen[:-2] + end + [gen[-2] + n2, gen[-1] + n2]
for gen in gens1]
gens2 = [start + [x + n1 for x in gen] for gen in gens2]
else:
gens1 = [gen + end for gen in gens1]
gens2 = [start + [x + n1 for x in gen] for gen in gens2]
res = gens1 + gens2
return res
def bsgs_direct_product(base1, gens1, base2, gens2, signed=True):
"""
Direct product of two BSGS.
Parameters
==========
base1 : base of the first BSGS.
gens1 : strong generating sequence of the first BSGS.
base2, gens2 : similarly for the second BSGS.
signed : flag for signed permutations.
Examples
========
>>> from sympy.combinatorics.tensor_can import (get_symmetric_group_sgs, bsgs_direct_product)
>>> base1, gens1 = get_symmetric_group_sgs(1)
>>> base2, gens2 = get_symmetric_group_sgs(2)
>>> bsgs_direct_product(base1, gens1, base2, gens2)
([1], [(4)(1 2)])
"""
s = 2 if signed else 0
n1 = gens1[0].size - s
base = list(base1)
base += [x + n1 for x in base2]
gens1 = [h._array_form for h in gens1]
gens2 = [h._array_form for h in gens2]
gens = perm_af_direct_product(gens1, gens2, signed)
size = len(gens[0])
id_af = list(range(size))
gens = [h for h in gens if h != id_af]
if not gens:
gens = [id_af]
return base, [_af_new(h) for h in gens]
def get_symmetric_group_sgs(n, antisym=False):
"""
Return base, gens of the minimal BSGS for (anti)symmetric tensor
Parameters
==========
n : rank of the tensor
antisym : bool
``antisym = False`` symmetric tensor
``antisym = True`` antisymmetric tensor
Examples
========
>>> from sympy.combinatorics.tensor_can import get_symmetric_group_sgs
>>> get_symmetric_group_sgs(3)
([0, 1], [(4)(0 1), (4)(1 2)])
"""
if n == 1:
return [], [_af_new(list(range(3)))]
gens = [Permutation(n - 1)(i, i + 1)._array_form for i in range(n - 1)]
if antisym == 0:
gens = [x + [n, n + 1] for x in gens]
else:
gens = [x + [n + 1, n] for x in gens]
base = list(range(n - 1))
return base, [_af_new(h) for h in gens]
riemann_bsgs = [0, 2], [Permutation(0, 1)(4, 5), Permutation(2, 3)(4, 5),
Permutation(5)(0, 2)(1, 3)]
def get_transversals(base, gens):
"""
Return transversals for the group with BSGS base, gens
"""
if not base:
return []
stabs = _distribute_gens_by_base(base, gens)
orbits, transversals = _orbits_transversals_from_bsgs(base, stabs)
transversals = [{x: h._array_form for x, h in y.items()} for y in
transversals]
return transversals
def _is_minimal_bsgs(base, gens):
"""
Check if the BSGS has minimal base under lexigographic order.
base, gens BSGS
Examples
========
>>> from sympy.combinatorics import Permutation
>>> from sympy.combinatorics.tensor_can import riemann_bsgs, _is_minimal_bsgs
>>> _is_minimal_bsgs(*riemann_bsgs)
True
>>> riemann_bsgs1 = ([2, 0], ([Permutation(5)(0, 1)(4, 5), Permutation(5)(0, 2)(1, 3)]))
>>> _is_minimal_bsgs(*riemann_bsgs1)
False
"""
base1 = []
sgs1 = gens[:]
size = gens[0].size
for i in range(size):
if not all(h._array_form[i] == i for h in sgs1):
base1.append(i)
sgs1 = [h for h in sgs1 if h._array_form[i] == i]
return base1 == base
def get_minimal_bsgs(base, gens):
"""
Compute a minimal GSGS
base, gens BSGS
If base, gens is a minimal BSGS return it; else return a minimal BSGS
if it fails in finding one, it returns None
TODO: use baseswap in the case in which if it fails in finding a
minimal BSGS
Examples
========
>>> from sympy.combinatorics import Permutation
>>> from sympy.combinatorics.tensor_can import get_minimal_bsgs
>>> riemann_bsgs1 = ([2, 0], ([Permutation(5)(0, 1)(4, 5), Permutation(5)(0, 2)(1, 3)]))
>>> get_minimal_bsgs(*riemann_bsgs1)
([0, 2], [(0 1)(4 5), (5)(0 2)(1 3), (2 3)(4 5)])
"""
G = PermutationGroup(gens)
base, gens = G.schreier_sims_incremental()
if not _is_minimal_bsgs(base, gens):
return None
return base, gens
def tensor_gens(base, gens, list_free_indices, sym=0):
"""
Returns size, res_base, res_gens BSGS for n tensors of the
same type.
Explanation
===========
base, gens BSGS for tensors of this type
list_free_indices list of the slots occupied by fixed indices
for each of the tensors
sym symmetry under commutation of two tensors
sym None no symmetry
sym 0 commuting
sym 1 anticommuting
Examples
========
>>> from sympy.combinatorics.tensor_can import tensor_gens, get_symmetric_group_sgs
two symmetric tensors with 3 indices without free indices
>>> base, gens = get_symmetric_group_sgs(3)
>>> tensor_gens(base, gens, [[], []])
(8, [0, 1, 3, 4], [(7)(0 1), (7)(1 2), (7)(3 4), (7)(4 5), (7)(0 3)(1 4)(2 5)])
two symmetric tensors with 3 indices with free indices in slot 1 and 0
>>> tensor_gens(base, gens, [[1], [0]])
(8, [0, 4], [(7)(0 2), (7)(4 5)])
four symmetric tensors with 3 indices, two of which with free indices
"""
def _get_bsgs(G, base, gens, free_indices):
"""
return the BSGS for G.pointwise_stabilizer(free_indices)
"""
if not free_indices:
return base[:], gens[:]
else:
H = G.pointwise_stabilizer(free_indices)
base, sgs = H.schreier_sims_incremental()
return base, sgs
# if not base there is no slot symmetry for the component tensors
# if list_free_indices.count([]) < 2 there is no commutation symmetry
# so there is no resulting slot symmetry
if not base and list_free_indices.count([]) < 2:
n = len(list_free_indices)
size = gens[0].size
size = n * (size - 2) + 2
return size, [], [_af_new(list(range(size)))]
# if any(list_free_indices) one needs to compute the pointwise
# stabilizer, so G is needed
if any(list_free_indices):
G = PermutationGroup(gens)
else:
G = None
# no_free list of lists of indices for component tensors without fixed
# indices
no_free = []
size = gens[0].size
id_af = list(range(size))
num_indices = size - 2
if not list_free_indices[0]:
no_free.append(list(range(num_indices)))
res_base, res_gens = _get_bsgs(G, base, gens, list_free_indices[0])
for i in range(1, len(list_free_indices)):
base1, gens1 = _get_bsgs(G, base, gens, list_free_indices[i])
res_base, res_gens = bsgs_direct_product(res_base, res_gens,
base1, gens1, 1)
if not list_free_indices[i]:
no_free.append(list(range(size - 2, size - 2 + num_indices)))
size += num_indices
nr = size - 2
res_gens = [h for h in res_gens if h._array_form != id_af]
# if sym there are no commuting tensors stop here
if sym is None or not no_free:
if not res_gens:
res_gens = [_af_new(id_af)]
return size, res_base, res_gens
# if the component tensors have moinimal BSGS, so is their direct
# product P; the slot symmetry group is S = P*C, where C is the group
# to (anti)commute the component tensors with no free indices
# a stabilizer has the property S_i = P_i*C_i;
# the BSGS of P*C has SGS_P + SGS_C and the base is
# the ordered union of the bases of P and C.
# If P has minimal BSGS, so has S with this base.
base_comm = []
for i in range(len(no_free) - 1):
ind1 = no_free[i]
ind2 = no_free[i + 1]
a = list(range(ind1[0]))
a.extend(ind2)
a.extend(ind1)
base_comm.append(ind1[0])
a.extend(list(range(ind2[-1] + 1, nr)))
if sym == 0:
a.extend([nr, nr + 1])
else:
a.extend([nr + 1, nr])
res_gens.append(_af_new(a))
res_base = list(res_base)
# each base is ordered; order the union of the two bases
for i in base_comm:
if i not in res_base:
res_base.append(i)
res_base.sort()
if not res_gens:
res_gens = [_af_new(id_af)]
return size, res_base, res_gens
def gens_products(*v):
"""
Returns size, res_base, res_gens BSGS for n tensors of different types.
Explanation
===========
v is a sequence of (base_i, gens_i, free_i, sym_i)
where
base_i, gens_i BSGS of tensor of type `i`
free_i list of the fixed slots for each of the tensors
of type `i`; if there are `n_i` tensors of type `i`
and none of them have fixed slots, `free = [[]]*n_i`
sym 0 (1) if the tensors of type `i` (anti)commute among themselves
Examples
========
>>> from sympy.combinatorics.tensor_can import get_symmetric_group_sgs, gens_products
>>> base, gens = get_symmetric_group_sgs(2)
>>> gens_products((base, gens, [[], []], 0))
(6, [0, 2], [(5)(0 1), (5)(2 3), (5)(0 2)(1 3)])
>>> gens_products((base, gens, [[1], []], 0))
(6, [2], [(5)(2 3)])
"""
res_size, res_base, res_gens = tensor_gens(*v[0])
for i in range(1, len(v)):
size, base, gens = tensor_gens(*v[i])
res_base, res_gens = bsgs_direct_product(res_base, res_gens, base,
gens, 1)
res_size = res_gens[0].size
id_af = list(range(res_size))
res_gens = [h for h in res_gens if h != id_af]
if not res_gens:
res_gens = [id_af]
return res_size, res_base, res_gens
PK ]ZZZ�����+ �+ sympy/combinatorics/testutil.pyfrom sympy.combinatorics import Permutation
from sympy.combinatorics.util import _distribute_gens_by_base
rmul = Permutation.rmul
def _cmp_perm_lists(first, second):
"""
Compare two lists of permutations as sets.
Explanation
===========
This is used for testing purposes. Since the array form of a
permutation is currently a list, Permutation is not hashable
and cannot be put into a set.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> from sympy.combinatorics.testutil import _cmp_perm_lists
>>> a = Permutation([0, 2, 3, 4, 1])
>>> b = Permutation([1, 2, 0, 4, 3])
>>> c = Permutation([3, 4, 0, 1, 2])
>>> ls1 = [a, b, c]
>>> ls2 = [b, c, a]
>>> _cmp_perm_lists(ls1, ls2)
True
"""
return {tuple(a) for a in first} == \
{tuple(a) for a in second}
def _naive_list_centralizer(self, other, af=False):
from sympy.combinatorics.perm_groups import PermutationGroup
"""
Return a list of elements for the centralizer of a subgroup/set/element.
Explanation
===========
This is a brute force implementation that goes over all elements of the
group and checks for membership in the centralizer. It is used to
test ``.centralizer()`` from ``sympy.combinatorics.perm_groups``.
Examples
========
>>> from sympy.combinatorics.testutil import _naive_list_centralizer
>>> from sympy.combinatorics.named_groups import DihedralGroup
>>> D = DihedralGroup(4)
>>> _naive_list_centralizer(D, D)
[Permutation([0, 1, 2, 3]), Permutation([2, 3, 0, 1])]
See Also
========
sympy.combinatorics.perm_groups.centralizer
"""
from sympy.combinatorics.permutations import _af_commutes_with
if hasattr(other, 'generators'):
elements = list(self.generate_dimino(af=True))
gens = [x._array_form for x in other.generators]
commutes_with_gens = lambda x: all(_af_commutes_with(x, gen) for gen in gens)
centralizer_list = []
if not af:
for element in elements:
if commutes_with_gens(element):
centralizer_list.append(Permutation._af_new(element))
else:
for element in elements:
if commutes_with_gens(element):
centralizer_list.append(element)
return centralizer_list
elif hasattr(other, 'getitem'):
return _naive_list_centralizer(self, PermutationGroup(other), af)
elif hasattr(other, 'array_form'):
return _naive_list_centralizer(self, PermutationGroup([other]), af)
def _verify_bsgs(group, base, gens):
"""
Verify the correctness of a base and strong generating set.
Explanation
===========
This is a naive implementation using the definition of a base and a strong
generating set relative to it. There are other procedures for
verifying a base and strong generating set, but this one will
serve for more robust testing.
Examples
========
>>> from sympy.combinatorics.named_groups import AlternatingGroup
>>> from sympy.combinatorics.testutil import _verify_bsgs
>>> A = AlternatingGroup(4)
>>> A.schreier_sims()
>>> _verify_bsgs(A, A.base, A.strong_gens)
True
See Also
========
sympy.combinatorics.perm_groups.PermutationGroup.schreier_sims
"""
from sympy.combinatorics.perm_groups import PermutationGroup
strong_gens_distr = _distribute_gens_by_base(base, gens)
current_stabilizer = group
for i in range(len(base)):
candidate = PermutationGroup(strong_gens_distr[i])
if current_stabilizer.order() != candidate.order():
return False
current_stabilizer = current_stabilizer.stabilizer(base[i])
if current_stabilizer.order() != 1:
return False
return True
def _verify_centralizer(group, arg, centr=None):
"""
Verify the centralizer of a group/set/element inside another group.
This is used for testing ``.centralizer()`` from
``sympy.combinatorics.perm_groups``
Examples
========
>>> from sympy.combinatorics.named_groups import (SymmetricGroup,
... AlternatingGroup)
>>> from sympy.combinatorics.perm_groups import PermutationGroup
>>> from sympy.combinatorics.permutations import Permutation
>>> from sympy.combinatorics.testutil import _verify_centralizer
>>> S = SymmetricGroup(5)
>>> A = AlternatingGroup(5)
>>> centr = PermutationGroup([Permutation([0, 1, 2, 3, 4])])
>>> _verify_centralizer(S, A, centr)
True
See Also
========
_naive_list_centralizer,
sympy.combinatorics.perm_groups.PermutationGroup.centralizer,
_cmp_perm_lists
"""
if centr is None:
centr = group.centralizer(arg)
centr_list = list(centr.generate_dimino(af=True))
centr_list_naive = _naive_list_centralizer(group, arg, af=True)
return _cmp_perm_lists(centr_list, centr_list_naive)
def _verify_normal_closure(group, arg, closure=None):
from sympy.combinatorics.perm_groups import PermutationGroup
"""
Verify the normal closure of a subgroup/subset/element in a group.
This is used to test
sympy.combinatorics.perm_groups.PermutationGroup.normal_closure
Examples
========
>>> from sympy.combinatorics.named_groups import (SymmetricGroup,
... AlternatingGroup)
>>> from sympy.combinatorics.testutil import _verify_normal_closure
>>> S = SymmetricGroup(3)
>>> A = AlternatingGroup(3)
>>> _verify_normal_closure(S, A, closure=A)
True
See Also
========
sympy.combinatorics.perm_groups.PermutationGroup.normal_closure
"""
if closure is None:
closure = group.normal_closure(arg)
conjugates = set()
if hasattr(arg, 'generators'):
subgr_gens = arg.generators
elif hasattr(arg, '__getitem__'):
subgr_gens = arg
elif hasattr(arg, 'array_form'):
subgr_gens = [arg]
for el in group.generate_dimino():
conjugates.update(gen ^ el for gen in subgr_gens)
naive_closure = PermutationGroup(list(conjugates))
return closure.is_subgroup(naive_closure)
def canonicalize_naive(g, dummies, sym, *v):
"""
Canonicalize tensor formed by tensors of the different types.
Explanation
===========
sym_i symmetry under exchange of two component tensors of type `i`
None no symmetry
0 commuting
1 anticommuting
Parameters
==========
g : Permutation representing the tensor.
dummies : List of dummy indices.
msym : Symmetry of the metric.
v : A list of (base_i, gens_i, n_i, sym_i) for tensors of type `i`.
base_i, gens_i BSGS for tensors of this type
n_i number of tensors of type `i`
Returns
=======
Returns 0 if the tensor is zero, else returns the array form of
the permutation representing the canonical form of the tensor.
Examples
========
>>> from sympy.combinatorics.testutil import canonicalize_naive
>>> from sympy.combinatorics.tensor_can import get_symmetric_group_sgs
>>> from sympy.combinatorics import Permutation
>>> g = Permutation([1, 3, 2, 0, 4, 5])
>>> base2, gens2 = get_symmetric_group_sgs(2)
>>> canonicalize_naive(g, [2, 3], 0, (base2, gens2, 2, 0))
[0, 2, 1, 3, 4, 5]
"""
from sympy.combinatorics.perm_groups import PermutationGroup
from sympy.combinatorics.tensor_can import gens_products, dummy_sgs
from sympy.combinatorics.permutations import _af_rmul
v1 = []
for i in range(len(v)):
base_i, gens_i, n_i, sym_i = v[i]
v1.append((base_i, gens_i, [[]]*n_i, sym_i))
size, sbase, sgens = gens_products(*v1)
dgens = dummy_sgs(dummies, sym, size-2)
if isinstance(sym, int):
num_types = 1
dummies = [dummies]
sym = [sym]
else:
num_types = len(sym)
dgens = []
for i in range(num_types):
dgens.extend(dummy_sgs(dummies[i], sym[i], size - 2))
S = PermutationGroup(sgens)
D = PermutationGroup([Permutation(x) for x in dgens])
dlist = list(D.generate(af=True))
g = g.array_form
st = set()
for s in S.generate(af=True):
h = _af_rmul(g, s)
for d in dlist:
q = tuple(_af_rmul(d, h))
st.add(q)
a = list(st)
a.sort()
prev = (0,)*size
for h in a:
if h[:-2] == prev[:-2]:
if h[-1] != prev[-1]:
return 0
prev = h
return list(a[0])
def graph_certificate(gr):
"""
Return a certificate for the graph
Parameters
==========
gr : adjacency list
Explanation
===========
The graph is assumed to be unoriented and without
external lines.
Associate to each vertex of the graph a symmetric tensor with
number of indices equal to the degree of the vertex; indices
are contracted when they correspond to the same line of the graph.
The canonical form of the tensor gives a certificate for the graph.
This is not an efficient algorithm to get the certificate of a graph.
Examples
========
>>> from sympy.combinatorics.testutil import graph_certificate
>>> gr1 = {0:[1, 2, 3, 5], 1:[0, 2, 4], 2:[0, 1, 3, 4], 3:[0, 2, 4], 4:[1, 2, 3, 5], 5:[0, 4]}
>>> gr2 = {0:[1, 5], 1:[0, 2, 3, 4], 2:[1, 3, 5], 3:[1, 2, 4, 5], 4:[1, 3, 5], 5:[0, 2, 3, 4]}
>>> c1 = graph_certificate(gr1)
>>> c2 = graph_certificate(gr2)
>>> c1
[0, 2, 4, 6, 1, 8, 10, 12, 3, 14, 16, 18, 5, 9, 15, 7, 11, 17, 13, 19, 20, 21]
>>> c1 == c2
True
"""
from sympy.combinatorics.permutations import _af_invert
from sympy.combinatorics.tensor_can import get_symmetric_group_sgs, canonicalize
items = list(gr.items())
items.sort(key=lambda x: len(x[1]), reverse=True)
pvert = [x[0] for x in items]
pvert = _af_invert(pvert)
# the indices of the tensor are twice the number of lines of the graph
num_indices = 0
for v, neigh in items:
num_indices += len(neigh)
# associate to each vertex its indices; for each line
# between two vertices assign the
# even index to the vertex which comes first in items,
# the odd index to the other vertex
vertices = [[] for i in items]
i = 0
for v, neigh in items:
for v2 in neigh:
if pvert[v] < pvert[v2]:
vertices[pvert[v]].append(i)
vertices[pvert[v2]].append(i+1)
i += 2
g = []
for v in vertices:
g.extend(v)
assert len(g) == num_indices
g += [num_indices, num_indices + 1]
size = num_indices + 2
assert sorted(g) == list(range(size))
g = Permutation(g)
vlen = [0]*(len(vertices[0])+1)
for neigh in vertices:
vlen[len(neigh)] += 1
v = []
for i in range(len(vlen)):
n = vlen[i]
if n:
base, gens = get_symmetric_group_sgs(i)
v.append((base, gens, n, 0))
v.reverse()
dummies = list(range(num_indices))
can = canonicalize(g, dummies, 0, *v)
return can
PK ]ZZZ�gը? �? sympy/combinatorics/util.pyfrom sympy.combinatorics.permutations import Permutation, _af_invert, _af_rmul
from sympy.ntheory import isprime
rmul = Permutation.rmul
_af_new = Permutation._af_new
############################################
#
# Utilities for computational group theory
#
############################################
def _base_ordering(base, degree):
r"""
Order `\{0, 1, \dots, n-1\}` so that base points come first and in order.
Parameters
==========
base : the base
degree : the degree of the associated permutation group
Returns
=======
A list ``base_ordering`` such that ``base_ordering[point]`` is the
number of ``point`` in the ordering.
Examples
========
>>> from sympy.combinatorics import SymmetricGroup
>>> from sympy.combinatorics.util import _base_ordering
>>> S = SymmetricGroup(4)
>>> S.schreier_sims()
>>> _base_ordering(S.base, S.degree)
[0, 1, 2, 3]
Notes
=====
This is used in backtrack searches, when we define a relation `\ll` on
the underlying set for a permutation group of degree `n`,
`\{0, 1, \dots, n-1\}`, so that if `(b_1, b_2, \dots, b_k)` is a base we
have `b_i \ll b_j` whenever `i<j` and `b_i \ll a` for all
`i\in\{1,2, \dots, k\}` and `a` is not in the base. The idea is developed
and applied to backtracking algorithms in [1], pp.108-132. The points
that are not in the base are taken in increasing order.
References
==========
.. [1] Holt, D., Eick, B., O'Brien, E.
"Handbook of computational group theory"
"""
base_len = len(base)
ordering = [0]*degree
for i in range(base_len):
ordering[base[i]] = i
current = base_len
for i in range(degree):
if i not in base:
ordering[i] = current
current += 1
return ordering
def _check_cycles_alt_sym(perm):
"""
Checks for cycles of prime length p with n/2 < p < n-2.
Explanation
===========
Here `n` is the degree of the permutation. This is a helper function for
the function is_alt_sym from sympy.combinatorics.perm_groups.
Examples
========
>>> from sympy.combinatorics.util import _check_cycles_alt_sym
>>> from sympy.combinatorics import Permutation
>>> a = Permutation([[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10], [11, 12]])
>>> _check_cycles_alt_sym(a)
False
>>> b = Permutation([[0, 1, 2, 3, 4, 5, 6], [7, 8, 9, 10]])
>>> _check_cycles_alt_sym(b)
True
See Also
========
sympy.combinatorics.perm_groups.PermutationGroup.is_alt_sym
"""
n = perm.size
af = perm.array_form
current_len = 0
total_len = 0
used = set()
for i in range(n//2):
if i not in used and i < n//2 - total_len:
current_len = 1
used.add(i)
j = i
while af[j] != i:
current_len += 1
j = af[j]
used.add(j)
total_len += current_len
if current_len > n//2 and current_len < n - 2 and isprime(current_len):
return True
return False
def _distribute_gens_by_base(base, gens):
r"""
Distribute the group elements ``gens`` by membership in basic stabilizers.
Explanation
===========
Notice that for a base `(b_1, b_2, \dots, b_k)`, the basic stabilizers
are defined as `G^{(i)} = G_{b_1, \dots, b_{i-1}}` for
`i \in\{1, 2, \dots, k\}`.
Parameters
==========
base : a sequence of points in `\{0, 1, \dots, n-1\}`
gens : a list of elements of a permutation group of degree `n`.
Returns
=======
list
List of length `k`, where `k` is the length of *base*. The `i`-th entry
contains those elements in *gens* which fix the first `i` elements of
*base* (so that the `0`-th entry is equal to *gens* itself). If no
element fixes the first `i` elements of *base*, the `i`-th element is
set to a list containing the identity element.
Examples
========
>>> from sympy.combinatorics.named_groups import DihedralGroup
>>> from sympy.combinatorics.util import _distribute_gens_by_base
>>> D = DihedralGroup(3)
>>> D.schreier_sims()
>>> D.strong_gens
[(0 1 2), (0 2), (1 2)]
>>> D.base
[0, 1]
>>> _distribute_gens_by_base(D.base, D.strong_gens)
[[(0 1 2), (0 2), (1 2)],
[(1 2)]]
See Also
========
_strong_gens_from_distr, _orbits_transversals_from_bsgs,
_handle_precomputed_bsgs
"""
base_len = len(base)
degree = gens[0].size
stabs = [[] for _ in range(base_len)]
max_stab_index = 0
for gen in gens:
j = 0
while j < base_len - 1 and gen._array_form[base[j]] == base[j]:
j += 1
if j > max_stab_index:
max_stab_index = j
for k in range(j + 1):
stabs[k].append(gen)
for i in range(max_stab_index + 1, base_len):
stabs[i].append(_af_new(list(range(degree))))
return stabs
def _handle_precomputed_bsgs(base, strong_gens, transversals=None,
basic_orbits=None, strong_gens_distr=None):
"""
Calculate BSGS-related structures from those present.
Explanation
===========
The base and strong generating set must be provided; if any of the
transversals, basic orbits or distributed strong generators are not
provided, they will be calculated from the base and strong generating set.
Parameters
==========
base : the base
strong_gens : the strong generators
transversals : basic transversals
basic_orbits : basic orbits
strong_gens_distr : strong generators distributed by membership in basic stabilizers
Returns
=======
(transversals, basic_orbits, strong_gens_distr)
where *transversals* are the basic transversals, *basic_orbits* are the
basic orbits, and *strong_gens_distr* are the strong generators distributed
by membership in basic stabilizers.
Examples
========
>>> from sympy.combinatorics.named_groups import DihedralGroup
>>> from sympy.combinatorics.util import _handle_precomputed_bsgs
>>> D = DihedralGroup(3)
>>> D.schreier_sims()
>>> _handle_precomputed_bsgs(D.base, D.strong_gens,
... basic_orbits=D.basic_orbits)
([{0: (2), 1: (0 1 2), 2: (0 2)}, {1: (2), 2: (1 2)}], [[0, 1, 2], [1, 2]], [[(0 1 2), (0 2), (1 2)], [(1 2)]])
See Also
========
_orbits_transversals_from_bsgs, _distribute_gens_by_base
"""
if strong_gens_distr is None:
strong_gens_distr = _distribute_gens_by_base(base, strong_gens)
if transversals is None:
if basic_orbits is None:
basic_orbits, transversals = \
_orbits_transversals_from_bsgs(base, strong_gens_distr)
else:
transversals = \
_orbits_transversals_from_bsgs(base, strong_gens_distr,
transversals_only=True)
else:
if basic_orbits is None:
base_len = len(base)
basic_orbits = [None]*base_len
for i in range(base_len):
basic_orbits[i] = list(transversals[i].keys())
return transversals, basic_orbits, strong_gens_distr
def _orbits_transversals_from_bsgs(base, strong_gens_distr,
transversals_only=False, slp=False):
"""
Compute basic orbits and transversals from a base and strong generating set.
Explanation
===========
The generators are provided as distributed across the basic stabilizers.
If the optional argument ``transversals_only`` is set to True, only the
transversals are returned.
Parameters
==========
base : The base.
strong_gens_distr : Strong generators distributed by membership in basic stabilizers.
transversals_only : bool, default: False
A flag switching between returning only the
transversals and both orbits and transversals.
slp : bool, default: False
If ``True``, return a list of dictionaries containing the
generator presentations of the elements of the transversals,
i.e. the list of indices of generators from ``strong_gens_distr[i]``
such that their product is the relevant transversal element.
Examples
========
>>> from sympy.combinatorics import SymmetricGroup
>>> from sympy.combinatorics.util import _distribute_gens_by_base
>>> S = SymmetricGroup(3)
>>> S.schreier_sims()
>>> strong_gens_distr = _distribute_gens_by_base(S.base, S.strong_gens)
>>> (S.base, strong_gens_distr)
([0, 1], [[(0 1 2), (2)(0 1), (1 2)], [(1 2)]])
See Also
========
_distribute_gens_by_base, _handle_precomputed_bsgs
"""
from sympy.combinatorics.perm_groups import _orbit_transversal
base_len = len(base)
degree = strong_gens_distr[0][0].size
transversals = [None]*base_len
slps = [None]*base_len
if transversals_only is False:
basic_orbits = [None]*base_len
for i in range(base_len):
transversals[i], slps[i] = _orbit_transversal(degree, strong_gens_distr[i],
base[i], pairs=True, slp=True)
transversals[i] = dict(transversals[i])
if transversals_only is False:
basic_orbits[i] = list(transversals[i].keys())
if transversals_only:
return transversals
else:
if not slp:
return basic_orbits, transversals
return basic_orbits, transversals, slps
def _remove_gens(base, strong_gens, basic_orbits=None, strong_gens_distr=None):
"""
Remove redundant generators from a strong generating set.
Parameters
==========
base : a base
strong_gens : a strong generating set relative to *base*
basic_orbits : basic orbits
strong_gens_distr : strong generators distributed by membership in basic stabilizers
Returns
=======
A strong generating set with respect to ``base`` which is a subset of
``strong_gens``.
Examples
========
>>> from sympy.combinatorics import SymmetricGroup
>>> from sympy.combinatorics.util import _remove_gens
>>> from sympy.combinatorics.testutil import _verify_bsgs
>>> S = SymmetricGroup(15)
>>> base, strong_gens = S.schreier_sims_incremental()
>>> new_gens = _remove_gens(base, strong_gens)
>>> len(new_gens)
14
>>> _verify_bsgs(S, base, new_gens)
True
Notes
=====
This procedure is outlined in [1],p.95.
References
==========
.. [1] Holt, D., Eick, B., O'Brien, E.
"Handbook of computational group theory"
"""
from sympy.combinatorics.perm_groups import _orbit
base_len = len(base)
degree = strong_gens[0].size
if strong_gens_distr is None:
strong_gens_distr = _distribute_gens_by_base(base, strong_gens)
if basic_orbits is None:
basic_orbits = []
for i in range(base_len):
basic_orbit = _orbit(degree, strong_gens_distr[i], base[i])
basic_orbits.append(basic_orbit)
strong_gens_distr.append([])
res = strong_gens[:]
for i in range(base_len - 1, -1, -1):
gens_copy = strong_gens_distr[i][:]
for gen in strong_gens_distr[i]:
if gen not in strong_gens_distr[i + 1]:
temp_gens = gens_copy[:]
temp_gens.remove(gen)
if temp_gens == []:
continue
temp_orbit = _orbit(degree, temp_gens, base[i])
if temp_orbit == basic_orbits[i]:
gens_copy.remove(gen)
res.remove(gen)
return res
def _strip(g, base, orbits, transversals):
"""
Attempt to decompose a permutation using a (possibly partial) BSGS
structure.
Explanation
===========
This is done by treating the sequence ``base`` as an actual base, and
the orbits ``orbits`` and transversals ``transversals`` as basic orbits and
transversals relative to it.
This process is called "sifting". A sift is unsuccessful when a certain
orbit element is not found or when after the sift the decomposition
does not end with the identity element.
The argument ``transversals`` is a list of dictionaries that provides
transversal elements for the orbits ``orbits``.
Parameters
==========
g : permutation to be decomposed
base : sequence of points
orbits : list
A list in which the ``i``-th entry is an orbit of ``base[i]``
under some subgroup of the pointwise stabilizer of `
`base[0], base[1], ..., base[i - 1]``. The groups themselves are implicit
in this function since the only information we need is encoded in the orbits
and transversals
transversals : list
A list of orbit transversals associated with the orbits *orbits*.
Examples
========
>>> from sympy.combinatorics import Permutation, SymmetricGroup
>>> from sympy.combinatorics.util import _strip
>>> S = SymmetricGroup(5)
>>> S.schreier_sims()
>>> g = Permutation([0, 2, 3, 1, 4])
>>> _strip(g, S.base, S.basic_orbits, S.basic_transversals)
((4), 5)
Notes
=====
The algorithm is described in [1],pp.89-90. The reason for returning
both the current state of the element being decomposed and the level
at which the sifting ends is that they provide important information for
the randomized version of the Schreier-Sims algorithm.
References
==========
.. [1] Holt, D., Eick, B., O'Brien, E."Handbook of computational group theory"
See Also
========
sympy.combinatorics.perm_groups.PermutationGroup.schreier_sims
sympy.combinatorics.perm_groups.PermutationGroup.schreier_sims_random
"""
h = g._array_form
base_len = len(base)
for i in range(base_len):
beta = h[base[i]]
if beta == base[i]:
continue
if beta not in orbits[i]:
return _af_new(h), i + 1
u = transversals[i][beta]._array_form
h = _af_rmul(_af_invert(u), h)
return _af_new(h), base_len + 1
def _strip_af(h, base, orbits, transversals, j, slp=[], slps={}):
"""
optimized _strip, with h, transversals and result in array form
if the stripped elements is the identity, it returns False, base_len + 1
j h[base[i]] == base[i] for i <= j
"""
base_len = len(base)
for i in range(j+1, base_len):
beta = h[base[i]]
if beta == base[i]:
continue
if beta not in orbits[i]:
if not slp:
return h, i + 1
return h, i + 1, slp
u = transversals[i][beta]
if h == u:
if not slp:
return False, base_len + 1
return False, base_len + 1, slp
h = _af_rmul(_af_invert(u), h)
if slp:
u_slp = slps[i][beta][:]
u_slp.reverse()
u_slp = [(i, (g,)) for g in u_slp]
slp = u_slp + slp
if not slp:
return h, base_len + 1
return h, base_len + 1, slp
def _strong_gens_from_distr(strong_gens_distr):
"""
Retrieve strong generating set from generators of basic stabilizers.
This is just the union of the generators of the first and second basic
stabilizers.
Parameters
==========
strong_gens_distr : strong generators distributed by membership in basic stabilizers
Examples
========
>>> from sympy.combinatorics import SymmetricGroup
>>> from sympy.combinatorics.util import (_strong_gens_from_distr,
... _distribute_gens_by_base)
>>> S = SymmetricGroup(3)
>>> S.schreier_sims()
>>> S.strong_gens
[(0 1 2), (2)(0 1), (1 2)]
>>> strong_gens_distr = _distribute_gens_by_base(S.base, S.strong_gens)
>>> _strong_gens_from_distr(strong_gens_distr)
[(0 1 2), (2)(0 1), (1 2)]
See Also
========
_distribute_gens_by_base
"""
if len(strong_gens_distr) == 1:
return strong_gens_distr[0][:]
else:
result = strong_gens_distr[0]
for gen in strong_gens_distr[1]:
if gen not in result:
result.append(gen)
return result
PK ]ZZZ� -� � sympy/concrete/__init__.pyfrom .products import product, Product
from .summations import summation, Sum
__all__ = [
'product', 'Product',
'summation', 'Sum',
]
PK ]ZZZ{֨[�& �& sympy/concrete/delta.py"""
This module implements sums and products containing the Kronecker Delta function.
References
==========
.. [1] https://mathworld.wolfram.com/KroneckerDelta.html
"""
from .products import product
from .summations import Sum, summation
from sympy.core import Add, Mul, S, Dummy
from sympy.core.cache import cacheit
from sympy.core.sorting import default_sort_key
from sympy.functions import KroneckerDelta, Piecewise, piecewise_fold
from sympy.polys.polytools import factor
from sympy.sets.sets import Interval
from sympy.solvers.solvers import solve
@cacheit
def _expand_delta(expr, index):
"""
Expand the first Add containing a simple KroneckerDelta.
"""
if not expr.is_Mul:
return expr
delta = None
func = Add
terms = [S.One]
for h in expr.args:
if delta is None and h.is_Add and _has_simple_delta(h, index):
delta = True
func = h.func
terms = [terms[0]*t for t in h.args]
else:
terms = [t*h for t in terms]
return func(*terms)
@cacheit
def _extract_delta(expr, index):
"""
Extract a simple KroneckerDelta from the expression.
Explanation
===========
Returns the tuple ``(delta, newexpr)`` where:
- ``delta`` is a simple KroneckerDelta expression if one was found,
or ``None`` if no simple KroneckerDelta expression was found.
- ``newexpr`` is a Mul containing the remaining terms; ``expr`` is
returned unchanged if no simple KroneckerDelta expression was found.
Examples
========
>>> from sympy import KroneckerDelta
>>> from sympy.concrete.delta import _extract_delta
>>> from sympy.abc import x, y, i, j, k
>>> _extract_delta(4*x*y*KroneckerDelta(i, j), i)
(KroneckerDelta(i, j), 4*x*y)
>>> _extract_delta(4*x*y*KroneckerDelta(i, j), k)
(None, 4*x*y*KroneckerDelta(i, j))
See Also
========
sympy.functions.special.tensor_functions.KroneckerDelta
deltaproduct
deltasummation
"""
if not _has_simple_delta(expr, index):
return (None, expr)
if isinstance(expr, KroneckerDelta):
return (expr, S.One)
if not expr.is_Mul:
raise ValueError("Incorrect expr")
delta = None
terms = []
for arg in expr.args:
if delta is None and _is_simple_delta(arg, index):
delta = arg
else:
terms.append(arg)
return (delta, expr.func(*terms))
@cacheit
def _has_simple_delta(expr, index):
"""
Returns True if ``expr`` is an expression that contains a KroneckerDelta
that is simple in the index ``index``, meaning that this KroneckerDelta
is nonzero for a single value of the index ``index``.
"""
if expr.has(KroneckerDelta):
if _is_simple_delta(expr, index):
return True
if expr.is_Add or expr.is_Mul:
for arg in expr.args:
if _has_simple_delta(arg, index):
return True
return False
@cacheit
def _is_simple_delta(delta, index):
"""
Returns True if ``delta`` is a KroneckerDelta and is nonzero for a single
value of the index ``index``.
"""
if isinstance(delta, KroneckerDelta) and delta.has(index):
p = (delta.args[0] - delta.args[1]).as_poly(index)
if p:
return p.degree() == 1
return False
@cacheit
def _remove_multiple_delta(expr):
"""
Evaluate products of KroneckerDelta's.
"""
if expr.is_Add:
return expr.func(*list(map(_remove_multiple_delta, expr.args)))
if not expr.is_Mul:
return expr
eqs = []
newargs = []
for arg in expr.args:
if isinstance(arg, KroneckerDelta):
eqs.append(arg.args[0] - arg.args[1])
else:
newargs.append(arg)
if not eqs:
return expr
solns = solve(eqs, dict=True)
if len(solns) == 0:
return S.Zero
elif len(solns) == 1:
for key in solns[0].keys():
newargs.append(KroneckerDelta(key, solns[0][key]))
expr2 = expr.func(*newargs)
if expr != expr2:
return _remove_multiple_delta(expr2)
return expr
@cacheit
def _simplify_delta(expr):
"""
Rewrite a KroneckerDelta's indices in its simplest form.
"""
if isinstance(expr, KroneckerDelta):
try:
slns = solve(expr.args[0] - expr.args[1], dict=True)
if slns and len(slns) == 1:
return Mul(*[KroneckerDelta(*(key, value))
for key, value in slns[0].items()])
except NotImplementedError:
pass
return expr
@cacheit
def deltaproduct(f, limit):
"""
Handle products containing a KroneckerDelta.
See Also
========
deltasummation
sympy.functions.special.tensor_functions.KroneckerDelta
sympy.concrete.products.product
"""
if ((limit[2] - limit[1]) < 0) == True:
return S.One
if not f.has(KroneckerDelta):
return product(f, limit)
if f.is_Add:
# Identify the term in the Add that has a simple KroneckerDelta
delta = None
terms = []
for arg in sorted(f.args, key=default_sort_key):
if delta is None and _has_simple_delta(arg, limit[0]):
delta = arg
else:
terms.append(arg)
newexpr = f.func(*terms)
k = Dummy("kprime", integer=True)
if isinstance(limit[1], int) and isinstance(limit[2], int):
result = deltaproduct(newexpr, limit) + sum(deltaproduct(newexpr, (limit[0], limit[1], ik - 1)) *
delta.subs(limit[0], ik) *
deltaproduct(newexpr, (limit[0], ik + 1, limit[2])) for ik in range(int(limit[1]), int(limit[2] + 1))
)
else:
result = deltaproduct(newexpr, limit) + deltasummation(
deltaproduct(newexpr, (limit[0], limit[1], k - 1)) *
delta.subs(limit[0], k) *
deltaproduct(newexpr, (limit[0], k + 1, limit[2])),
(k, limit[1], limit[2]),
no_piecewise=_has_simple_delta(newexpr, limit[0])
)
return _remove_multiple_delta(result)
delta, _ = _extract_delta(f, limit[0])
if not delta:
g = _expand_delta(f, limit[0])
if f != g:
try:
return factor(deltaproduct(g, limit))
except AssertionError:
return deltaproduct(g, limit)
return product(f, limit)
return _remove_multiple_delta(f.subs(limit[0], limit[1])*KroneckerDelta(limit[2], limit[1])) + \
S.One*_simplify_delta(KroneckerDelta(limit[2], limit[1] - 1))
@cacheit
def deltasummation(f, limit, no_piecewise=False):
"""
Handle summations containing a KroneckerDelta.
Explanation
===========
The idea for summation is the following:
- If we are dealing with a KroneckerDelta expression, i.e. KroneckerDelta(g(x), j),
we try to simplify it.
If we could simplify it, then we sum the resulting expression.
We already know we can sum a simplified expression, because only
simple KroneckerDelta expressions are involved.
If we could not simplify it, there are two cases:
1) The expression is a simple expression: we return the summation,
taking care if we are dealing with a Derivative or with a proper
KroneckerDelta.
2) The expression is not simple (i.e. KroneckerDelta(cos(x))): we can do
nothing at all.
- If the expr is a multiplication expr having a KroneckerDelta term:
First we expand it.
If the expansion did work, then we try to sum the expansion.
If not, we try to extract a simple KroneckerDelta term, then we have two
cases:
1) We have a simple KroneckerDelta term, so we return the summation.
2) We did not have a simple term, but we do have an expression with
simplified KroneckerDelta terms, so we sum this expression.
Examples
========
>>> from sympy import oo, symbols
>>> from sympy.abc import k
>>> i, j = symbols('i, j', integer=True, finite=True)
>>> from sympy.concrete.delta import deltasummation
>>> from sympy import KroneckerDelta
>>> deltasummation(KroneckerDelta(i, k), (k, -oo, oo))
1
>>> deltasummation(KroneckerDelta(i, k), (k, 0, oo))
Piecewise((1, i >= 0), (0, True))
>>> deltasummation(KroneckerDelta(i, k), (k, 1, 3))
Piecewise((1, (i >= 1) & (i <= 3)), (0, True))
>>> deltasummation(k*KroneckerDelta(i, j)*KroneckerDelta(j, k), (k, -oo, oo))
j*KroneckerDelta(i, j)
>>> deltasummation(j*KroneckerDelta(i, j), (j, -oo, oo))
i
>>> deltasummation(i*KroneckerDelta(i, j), (i, -oo, oo))
j
See Also
========
deltaproduct
sympy.functions.special.tensor_functions.KroneckerDelta
sympy.concrete.sums.summation
"""
if ((limit[2] - limit[1]) < 0) == True:
return S.Zero
if not f.has(KroneckerDelta):
return summation(f, limit)
x = limit[0]
g = _expand_delta(f, x)
if g.is_Add:
return piecewise_fold(
g.func(*[deltasummation(h, limit, no_piecewise) for h in g.args]))
# try to extract a simple KroneckerDelta term
delta, expr = _extract_delta(g, x)
if (delta is not None) and (delta.delta_range is not None):
dinf, dsup = delta.delta_range
if (limit[1] - dinf <= 0) == True and (limit[2] - dsup >= 0) == True:
no_piecewise = True
if not delta:
return summation(f, limit)
solns = solve(delta.args[0] - delta.args[1], x)
if len(solns) == 0:
return S.Zero
elif len(solns) != 1:
return Sum(f, limit)
value = solns[0]
if no_piecewise:
return expr.subs(x, value)
return Piecewise(
(expr.subs(x, value), Interval(*limit[1:3]).as_relational(value)),
(S.Zero, True)
)
PK ]ZZZ�:�X, X, % sympy/concrete/expr_with_intlimits.pyfrom sympy.concrete.expr_with_limits import ExprWithLimits
from sympy.core.singleton import S
from sympy.core.relational import Eq
class ReorderError(NotImplementedError):
"""
Exception raised when trying to reorder dependent limits.
"""
def __init__(self, expr, msg):
super().__init__(
"%s could not be reordered: %s." % (expr, msg))
class ExprWithIntLimits(ExprWithLimits):
"""
Superclass for Product and Sum.
See Also
========
sympy.concrete.expr_with_limits.ExprWithLimits
sympy.concrete.products.Product
sympy.concrete.summations.Sum
"""
__slots__ = ()
def change_index(self, var, trafo, newvar=None):
r"""
Change index of a Sum or Product.
Perform a linear transformation `x \mapsto a x + b` on the index variable
`x`. For `a` the only values allowed are `\pm 1`. A new variable to be used
after the change of index can also be specified.
Explanation
===========
``change_index(expr, var, trafo, newvar=None)`` where ``var`` specifies the
index variable `x` to transform. The transformation ``trafo`` must be linear
and given in terms of ``var``. If the optional argument ``newvar`` is
provided then ``var`` gets replaced by ``newvar`` in the final expression.
Examples
========
>>> from sympy import Sum, Product, simplify
>>> from sympy.abc import x, y, a, b, c, d, u, v, i, j, k, l
>>> S = Sum(x, (x, a, b))
>>> S.doit()
-a**2/2 + a/2 + b**2/2 + b/2
>>> Sn = S.change_index(x, x + 1, y)
>>> Sn
Sum(y - 1, (y, a + 1, b + 1))
>>> Sn.doit()
-a**2/2 + a/2 + b**2/2 + b/2
>>> Sn = S.change_index(x, -x, y)
>>> Sn
Sum(-y, (y, -b, -a))
>>> Sn.doit()
-a**2/2 + a/2 + b**2/2 + b/2
>>> Sn = S.change_index(x, x+u)
>>> Sn
Sum(-u + x, (x, a + u, b + u))
>>> Sn.doit()
-a**2/2 - a*u + a/2 + b**2/2 + b*u + b/2 - u*(-a + b + 1) + u
>>> simplify(Sn.doit())
-a**2/2 + a/2 + b**2/2 + b/2
>>> Sn = S.change_index(x, -x - u, y)
>>> Sn
Sum(-u - y, (y, -b - u, -a - u))
>>> Sn.doit()
-a**2/2 - a*u + a/2 + b**2/2 + b*u + b/2 - u*(-a + b + 1) + u
>>> simplify(Sn.doit())
-a**2/2 + a/2 + b**2/2 + b/2
>>> P = Product(i*j**2, (i, a, b), (j, c, d))
>>> P
Product(i*j**2, (i, a, b), (j, c, d))
>>> P2 = P.change_index(i, i+3, k)
>>> P2
Product(j**2*(k - 3), (k, a + 3, b + 3), (j, c, d))
>>> P3 = P2.change_index(j, -j, l)
>>> P3
Product(l**2*(k - 3), (k, a + 3, b + 3), (l, -d, -c))
When dealing with symbols only, we can make a
general linear transformation:
>>> Sn = S.change_index(x, u*x+v, y)
>>> Sn
Sum((-v + y)/u, (y, b*u + v, a*u + v))
>>> Sn.doit()
-v*(a*u - b*u + 1)/u + (a**2*u**2/2 + a*u*v + a*u/2 - b**2*u**2/2 - b*u*v + b*u/2 + v)/u
>>> simplify(Sn.doit())
a**2*u/2 + a/2 - b**2*u/2 + b/2
However, the last result can be inconsistent with usual
summation where the index increment is always 1. This is
obvious as we get back the original value only for ``u``
equal +1 or -1.
See Also
========
sympy.concrete.expr_with_intlimits.ExprWithIntLimits.index,
reorder_limit,
sympy.concrete.expr_with_intlimits.ExprWithIntLimits.reorder,
sympy.concrete.summations.Sum.reverse_order,
sympy.concrete.products.Product.reverse_order
"""
if newvar is None:
newvar = var
limits = []
for limit in self.limits:
if limit[0] == var:
p = trafo.as_poly(var)
if p.degree() != 1:
raise ValueError("Index transformation is not linear")
alpha = p.coeff_monomial(var)
beta = p.coeff_monomial(S.One)
if alpha.is_number:
if alpha == S.One:
limits.append((newvar, alpha*limit[1] + beta, alpha*limit[2] + beta))
elif alpha == S.NegativeOne:
limits.append((newvar, alpha*limit[2] + beta, alpha*limit[1] + beta))
else:
raise ValueError("Linear transformation results in non-linear summation stepsize")
else:
# Note that the case of alpha being symbolic can give issues if alpha < 0.
limits.append((newvar, alpha*limit[2] + beta, alpha*limit[1] + beta))
else:
limits.append(limit)
function = self.function.subs(var, (var - beta)/alpha)
function = function.subs(var, newvar)
return self.func(function, *limits)
def index(expr, x):
"""
Return the index of a dummy variable in the list of limits.
Explanation
===========
``index(expr, x)`` returns the index of the dummy variable ``x`` in the
limits of ``expr``. Note that we start counting with 0 at the inner-most
limits tuple.
Examples
========
>>> from sympy.abc import x, y, a, b, c, d
>>> from sympy import Sum, Product
>>> Sum(x*y, (x, a, b), (y, c, d)).index(x)
0
>>> Sum(x*y, (x, a, b), (y, c, d)).index(y)
1
>>> Product(x*y, (x, a, b), (y, c, d)).index(x)
0
>>> Product(x*y, (x, a, b), (y, c, d)).index(y)
1
See Also
========
reorder_limit, reorder, sympy.concrete.summations.Sum.reverse_order,
sympy.concrete.products.Product.reverse_order
"""
variables = [limit[0] for limit in expr.limits]
if variables.count(x) != 1:
raise ValueError(expr, "Number of instances of variable not equal to one")
else:
return variables.index(x)
def reorder(expr, *arg):
"""
Reorder limits in a expression containing a Sum or a Product.
Explanation
===========
``expr.reorder(*arg)`` reorders the limits in the expression ``expr``
according to the list of tuples given by ``arg``. These tuples can
contain numerical indices or index variable names or involve both.
Examples
========
>>> from sympy import Sum, Product
>>> from sympy.abc import x, y, z, a, b, c, d, e, f
>>> Sum(x*y, (x, a, b), (y, c, d)).reorder((x, y))
Sum(x*y, (y, c, d), (x, a, b))
>>> Sum(x*y*z, (x, a, b), (y, c, d), (z, e, f)).reorder((x, y), (x, z), (y, z))
Sum(x*y*z, (z, e, f), (y, c, d), (x, a, b))
>>> P = Product(x*y*z, (x, a, b), (y, c, d), (z, e, f))
>>> P.reorder((x, y), (x, z), (y, z))
Product(x*y*z, (z, e, f), (y, c, d), (x, a, b))
We can also select the index variables by counting them, starting
with the inner-most one:
>>> Sum(x**2, (x, a, b), (x, c, d)).reorder((0, 1))
Sum(x**2, (x, c, d), (x, a, b))
And of course we can mix both schemes:
>>> Sum(x*y, (x, a, b), (y, c, d)).reorder((y, x))
Sum(x*y, (y, c, d), (x, a, b))
>>> Sum(x*y, (x, a, b), (y, c, d)).reorder((y, 0))
Sum(x*y, (y, c, d), (x, a, b))
See Also
========
reorder_limit, index, sympy.concrete.summations.Sum.reverse_order,
sympy.concrete.products.Product.reverse_order
"""
new_expr = expr
for r in arg:
if len(r) != 2:
raise ValueError(r, "Invalid number of arguments")
index1 = r[0]
index2 = r[1]
if not isinstance(r[0], int):
index1 = expr.index(r[0])
if not isinstance(r[1], int):
index2 = expr.index(r[1])
new_expr = new_expr.reorder_limit(index1, index2)
return new_expr
def reorder_limit(expr, x, y):
"""
Interchange two limit tuples of a Sum or Product expression.
Explanation
===========
``expr.reorder_limit(x, y)`` interchanges two limit tuples. The
arguments ``x`` and ``y`` are integers corresponding to the index
variables of the two limits which are to be interchanged. The
expression ``expr`` has to be either a Sum or a Product.
Examples
========
>>> from sympy.abc import x, y, z, a, b, c, d, e, f
>>> from sympy import Sum, Product
>>> Sum(x*y*z, (x, a, b), (y, c, d), (z, e, f)).reorder_limit(0, 2)
Sum(x*y*z, (z, e, f), (y, c, d), (x, a, b))
>>> Sum(x**2, (x, a, b), (x, c, d)).reorder_limit(1, 0)
Sum(x**2, (x, c, d), (x, a, b))
>>> Product(x*y*z, (x, a, b), (y, c, d), (z, e, f)).reorder_limit(0, 2)
Product(x*y*z, (z, e, f), (y, c, d), (x, a, b))
See Also
========
index, reorder, sympy.concrete.summations.Sum.reverse_order,
sympy.concrete.products.Product.reverse_order
"""
var = {limit[0] for limit in expr.limits}
limit_x = expr.limits[x]
limit_y = expr.limits[y]
if (len(set(limit_x[1].free_symbols).intersection(var)) == 0 and
len(set(limit_x[2].free_symbols).intersection(var)) == 0 and
len(set(limit_y[1].free_symbols).intersection(var)) == 0 and
len(set(limit_y[2].free_symbols).intersection(var)) == 0):
limits = []
for i, limit in enumerate(expr.limits):
if i == x:
limits.append(limit_y)
elif i == y:
limits.append(limit_x)
else:
limits.append(limit)
return type(expr)(expr.function, *limits)
else:
raise ReorderError(expr, "could not interchange the two limits specified")
@property
def has_empty_sequence(self):
"""
Returns True if the Sum or Product is computed for an empty sequence.
Examples
========
>>> from sympy import Sum, Product, Symbol
>>> m = Symbol('m')
>>> Sum(m, (m, 1, 0)).has_empty_sequence
True
>>> Sum(m, (m, 1, 1)).has_empty_sequence
False
>>> M = Symbol('M', integer=True, positive=True)
>>> Product(m, (m, 1, M)).has_empty_sequence
False
>>> Product(m, (m, 2, M)).has_empty_sequence
>>> Product(m, (m, M + 1, M)).has_empty_sequence
True
>>> N = Symbol('N', integer=True, positive=True)
>>> Sum(m, (m, N, M)).has_empty_sequence
>>> N = Symbol('N', integer=True, negative=True)
>>> Sum(m, (m, N, M)).has_empty_sequence
False
See Also
========
has_reversed_limits
has_finite_limits
"""
ret_None = False
for lim in self.limits:
dif = lim[1] - lim[2]
eq = Eq(dif, 1)
if eq == True:
return True
elif eq == False:
continue
else:
ret_None = True
if ret_None:
return None
return False
PK ]ZZZ(�e�JU JU " sympy/concrete/expr_with_limits.pyfrom sympy.core.add import Add
from sympy.core.containers import Tuple
from sympy.core.expr import Expr
from sympy.core.function import AppliedUndef, UndefinedFunction
from sympy.core.mul import Mul
from sympy.core.relational import Equality, Relational
from sympy.core.singleton import S
from sympy.core.symbol import Symbol, Dummy
from sympy.core.sympify import sympify
from sympy.functions.elementary.piecewise import (piecewise_fold,
Piecewise)
from sympy.logic.boolalg import BooleanFunction
from sympy.matrices.matrixbase import MatrixBase
from sympy.sets.sets import Interval, Set
from sympy.sets.fancysets import Range
from sympy.tensor.indexed import Idx
from sympy.utilities import flatten
from sympy.utilities.iterables import sift, is_sequence
from sympy.utilities.exceptions import sympy_deprecation_warning
def _common_new(cls, function, *symbols, discrete, **assumptions):
"""Return either a special return value or the tuple,
(function, limits, orientation). This code is common to
both ExprWithLimits and AddWithLimits."""
function = sympify(function)
if isinstance(function, Equality):
# This transforms e.g. Integral(Eq(x, y)) to Eq(Integral(x), Integral(y))
# but that is only valid for definite integrals.
limits, orientation = _process_limits(*symbols, discrete=discrete)
if not (limits and all(len(limit) == 3 for limit in limits)):
sympy_deprecation_warning(
"""
Creating a indefinite integral with an Eq() argument is
deprecated.
This is because indefinite integrals do not preserve equality
due to the arbitrary constants. If you want an equality of
indefinite integrals, use Eq(Integral(a, x), Integral(b, x))
explicitly.
""",
deprecated_since_version="1.6",
active_deprecations_target="deprecated-indefinite-integral-eq",
stacklevel=5,
)
lhs = function.lhs
rhs = function.rhs
return Equality(cls(lhs, *symbols, **assumptions), \
cls(rhs, *symbols, **assumptions))
if function is S.NaN:
return S.NaN
if symbols:
limits, orientation = _process_limits(*symbols, discrete=discrete)
for i, li in enumerate(limits):
if len(li) == 4:
function = function.subs(li[0], li[-1])
limits[i] = Tuple(*li[:-1])
else:
# symbol not provided -- we can still try to compute a general form
free = function.free_symbols
if len(free) != 1:
raise ValueError(
"specify dummy variables for %s" % function)
limits, orientation = [Tuple(s) for s in free], 1
# denest any nested calls
while cls == type(function):
limits = list(function.limits) + limits
function = function.function
# Any embedded piecewise functions need to be brought out to the
# top level. We only fold Piecewise that contain the integration
# variable.
reps = {}
symbols_of_integration = {i[0] for i in limits}
for p in function.atoms(Piecewise):
if not p.has(*symbols_of_integration):
reps[p] = Dummy()
# mask off those that don't
function = function.xreplace(reps)
# do the fold
function = piecewise_fold(function)
# remove the masking
function = function.xreplace({v: k for k, v in reps.items()})
return function, limits, orientation
def _process_limits(*symbols, discrete=None):
"""Process the list of symbols and convert them to canonical limits,
storing them as Tuple(symbol, lower, upper). The orientation of
the function is also returned when the upper limit is missing
so (x, 1, None) becomes (x, None, 1) and the orientation is changed.
In the case that a limit is specified as (symbol, Range), a list of
length 4 may be returned if a change of variables is needed; the
expression that should replace the symbol in the expression is
the fourth element in the list.
"""
limits = []
orientation = 1
if discrete is None:
err_msg = 'discrete must be True or False'
elif discrete:
err_msg = 'use Range, not Interval or Relational'
else:
err_msg = 'use Interval or Relational, not Range'
for V in symbols:
if isinstance(V, (Relational, BooleanFunction)):
if discrete:
raise TypeError(err_msg)
variable = V.atoms(Symbol).pop()
V = (variable, V.as_set())
elif isinstance(V, Symbol) or getattr(V, '_diff_wrt', False):
if isinstance(V, Idx):
if V.lower is None or V.upper is None:
limits.append(Tuple(V))
else:
limits.append(Tuple(V, V.lower, V.upper))
else:
limits.append(Tuple(V))
continue
if is_sequence(V) and not isinstance(V, Set):
if len(V) == 2 and isinstance(V[1], Set):
V = list(V)
if isinstance(V[1], Interval): # includes Reals
if discrete:
raise TypeError(err_msg)
V[1:] = V[1].inf, V[1].sup
elif isinstance(V[1], Range):
if not discrete:
raise TypeError(err_msg)
lo = V[1].inf
hi = V[1].sup
dx = abs(V[1].step) # direction doesn't matter
if dx == 1:
V[1:] = [lo, hi]
else:
if lo is not S.NegativeInfinity:
V = [V[0]] + [0, (hi - lo)//dx, dx*V[0] + lo]
else:
V = [V[0]] + [0, S.Infinity, -dx*V[0] + hi]
else:
# more complicated sets would require splitting, e.g.
# Union(Interval(1, 3), interval(6,10))
raise NotImplementedError(
'expecting Range' if discrete else
'Relational or single Interval' )
V = sympify(flatten(V)) # list of sympified elements/None
if isinstance(V[0], (Symbol, Idx)) or getattr(V[0], '_diff_wrt', False):
newsymbol = V[0]
if len(V) == 3:
# general case
if V[2] is None and V[1] is not None:
orientation *= -1
V = [newsymbol] + [i for i in V[1:] if i is not None]
lenV = len(V)
if not isinstance(newsymbol, Idx) or lenV == 3:
if lenV == 4:
limits.append(Tuple(*V))
continue
if lenV == 3:
if isinstance(newsymbol, Idx):
# Idx represents an integer which may have
# specified values it can take on; if it is
# given such a value, an error is raised here
# if the summation would try to give it a larger
# or smaller value than permitted. None and Symbolic
# values will not raise an error.
lo, hi = newsymbol.lower, newsymbol.upper
try:
if lo is not None and not bool(V[1] >= lo):
raise ValueError("Summation will set Idx value too low.")
except TypeError:
pass
try:
if hi is not None and not bool(V[2] <= hi):
raise ValueError("Summation will set Idx value too high.")
except TypeError:
pass
limits.append(Tuple(*V))
continue
if lenV == 1 or (lenV == 2 and V[1] is None):
limits.append(Tuple(newsymbol))
continue
elif lenV == 2:
limits.append(Tuple(newsymbol, V[1]))
continue
raise ValueError('Invalid limits given: %s' % str(symbols))
return limits, orientation
class ExprWithLimits(Expr):
__slots__ = ('is_commutative',)
def __new__(cls, function, *symbols, **assumptions):
from sympy.concrete.products import Product
pre = _common_new(cls, function, *symbols,
discrete=issubclass(cls, Product), **assumptions)
if isinstance(pre, tuple):
function, limits, _ = pre
else:
return pre
# limits must have upper and lower bounds; the indefinite form
# is not supported. This restriction does not apply to AddWithLimits
if any(len(l) != 3 or None in l for l in limits):
raise ValueError('ExprWithLimits requires values for lower and upper bounds.')
obj = Expr.__new__(cls, **assumptions)
arglist = [function]
arglist.extend(limits)
obj._args = tuple(arglist)
obj.is_commutative = function.is_commutative # limits already checked
return obj
@property
def function(self):
"""Return the function applied across limits.
Examples
========
>>> from sympy import Integral
>>> from sympy.abc import x
>>> Integral(x**2, (x,)).function
x**2
See Also
========
limits, variables, free_symbols
"""
return self._args[0]
@property
def kind(self):
return self.function.kind
@property
def limits(self):
"""Return the limits of expression.
Examples
========
>>> from sympy import Integral
>>> from sympy.abc import x, i
>>> Integral(x**i, (i, 1, 3)).limits
((i, 1, 3),)
See Also
========
function, variables, free_symbols
"""
return self._args[1:]
@property
def variables(self):
"""Return a list of the limit variables.
>>> from sympy import Sum
>>> from sympy.abc import x, i
>>> Sum(x**i, (i, 1, 3)).variables
[i]
See Also
========
function, limits, free_symbols
as_dummy : Rename dummy variables
sympy.integrals.integrals.Integral.transform : Perform mapping on the dummy variable
"""
return [l[0] for l in self.limits]
@property
def bound_symbols(self):
"""Return only variables that are dummy variables.
Examples
========
>>> from sympy import Integral
>>> from sympy.abc import x, i, j, k
>>> Integral(x**i, (i, 1, 3), (j, 2), k).bound_symbols
[i, j]
See Also
========
function, limits, free_symbols
as_dummy : Rename dummy variables
sympy.integrals.integrals.Integral.transform : Perform mapping on the dummy variable
"""
return [l[0] for l in self.limits if len(l) != 1]
@property
def free_symbols(self):
"""
This method returns the symbols in the object, excluding those
that take on a specific value (i.e. the dummy symbols).
Examples
========
>>> from sympy import Sum
>>> from sympy.abc import x, y
>>> Sum(x, (x, y, 1)).free_symbols
{y}
"""
# don't test for any special values -- nominal free symbols
# should be returned, e.g. don't return set() if the
# function is zero -- treat it like an unevaluated expression.
function, limits = self.function, self.limits
# mask off non-symbol integration variables that have
# more than themself as a free symbol
reps = {i[0]: i[0] if i[0].free_symbols == {i[0]} else Dummy()
for i in self.limits}
function = function.xreplace(reps)
isyms = function.free_symbols
for xab in limits:
v = reps[xab[0]]
if len(xab) == 1:
isyms.add(v)
continue
# take out the target symbol
if v in isyms:
isyms.remove(v)
# add in the new symbols
for i in xab[1:]:
isyms.update(i.free_symbols)
reps = {v: k for k, v in reps.items()}
return {reps.get(_, _) for _ in isyms}
@property
def is_number(self):
"""Return True if the Sum has no free symbols, else False."""
return not self.free_symbols
def _eval_interval(self, x, a, b):
limits = [(i if i[0] != x else (x, a, b)) for i in self.limits]
integrand = self.function
return self.func(integrand, *limits)
def _eval_subs(self, old, new):
"""
Perform substitutions over non-dummy variables
of an expression with limits. Also, can be used
to specify point-evaluation of an abstract antiderivative.
Examples
========
>>> from sympy import Sum, oo
>>> from sympy.abc import s, n
>>> Sum(1/n**s, (n, 1, oo)).subs(s, 2)
Sum(n**(-2), (n, 1, oo))
>>> from sympy import Integral
>>> from sympy.abc import x, a
>>> Integral(a*x**2, x).subs(x, 4)
Integral(a*x**2, (x, 4))
See Also
========
variables : Lists the integration variables
transform : Perform mapping on the dummy variable for integrals
change_index : Perform mapping on the sum and product dummy variables
"""
func, limits = self.function, list(self.limits)
# If one of the expressions we are replacing is used as a func index
# one of two things happens.
# - the old variable first appears as a free variable
# so we perform all free substitutions before it becomes
# a func index.
# - the old variable first appears as a func index, in
# which case we ignore. See change_index.
# Reorder limits to match standard mathematical practice for scoping
limits.reverse()
if not isinstance(old, Symbol) or \
old.free_symbols.intersection(self.free_symbols):
sub_into_func = True
for i, xab in enumerate(limits):
if 1 == len(xab) and old == xab[0]:
if new._diff_wrt:
xab = (new,)
else:
xab = (old, old)
limits[i] = Tuple(xab[0], *[l._subs(old, new) for l in xab[1:]])
if len(xab[0].free_symbols.intersection(old.free_symbols)) != 0:
sub_into_func = False
break
if isinstance(old, (AppliedUndef, UndefinedFunction)):
sy2 = set(self.variables).intersection(set(new.atoms(Symbol)))
sy1 = set(self.variables).intersection(set(old.args))
if not sy2.issubset(sy1):
raise ValueError(
"substitution cannot create dummy dependencies")
sub_into_func = True
if sub_into_func:
func = func.subs(old, new)
else:
# old is a Symbol and a dummy variable of some limit
for i, xab in enumerate(limits):
if len(xab) == 3:
limits[i] = Tuple(xab[0], *[l._subs(old, new) for l in xab[1:]])
if old == xab[0]:
break
# simplify redundant limits (x, x) to (x, )
for i, xab in enumerate(limits):
if len(xab) == 2 and (xab[0] - xab[1]).is_zero:
limits[i] = Tuple(xab[0], )
# Reorder limits back to representation-form
limits.reverse()
return self.func(func, *limits)
@property
def has_finite_limits(self):
"""
Returns True if the limits are known to be finite, either by the
explicit bounds, assumptions on the bounds, or assumptions on the
variables. False if known to be infinite, based on the bounds.
None if not enough information is available to determine.
Examples
========
>>> from sympy import Sum, Integral, Product, oo, Symbol
>>> x = Symbol('x')
>>> Sum(x, (x, 1, 8)).has_finite_limits
True
>>> Integral(x, (x, 1, oo)).has_finite_limits
False
>>> M = Symbol('M')
>>> Sum(x, (x, 1, M)).has_finite_limits
>>> N = Symbol('N', integer=True)
>>> Product(x, (x, 1, N)).has_finite_limits
True
See Also
========
has_reversed_limits
"""
ret_None = False
for lim in self.limits:
if len(lim) == 3:
if any(l.is_infinite for l in lim[1:]):
# Any of the bounds are +/-oo
return False
elif any(l.is_infinite is None for l in lim[1:]):
# Maybe there are assumptions on the variable?
if lim[0].is_infinite is None:
ret_None = True
else:
if lim[0].is_infinite is None:
ret_None = True
if ret_None:
return None
return True
@property
def has_reversed_limits(self):
"""
Returns True if the limits are known to be in reversed order, either
by the explicit bounds, assumptions on the bounds, or assumptions on the
variables. False if known to be in normal order, based on the bounds.
None if not enough information is available to determine.
Examples
========
>>> from sympy import Sum, Integral, Product, oo, Symbol
>>> x = Symbol('x')
>>> Sum(x, (x, 8, 1)).has_reversed_limits
True
>>> Sum(x, (x, 1, oo)).has_reversed_limits
False
>>> M = Symbol('M')
>>> Integral(x, (x, 1, M)).has_reversed_limits
>>> N = Symbol('N', integer=True, positive=True)
>>> Sum(x, (x, 1, N)).has_reversed_limits
False
>>> Product(x, (x, 2, N)).has_reversed_limits
>>> Product(x, (x, 2, N)).subs(N, N + 2).has_reversed_limits
False
See Also
========
sympy.concrete.expr_with_intlimits.ExprWithIntLimits.has_empty_sequence
"""
ret_None = False
for lim in self.limits:
if len(lim) == 3:
var, a, b = lim
dif = b - a
if dif.is_extended_negative:
return True
elif dif.is_extended_nonnegative:
continue
else:
ret_None = True
else:
return None
if ret_None:
return None
return False
class AddWithLimits(ExprWithLimits):
r"""Represents unevaluated oriented additions.
Parent class for Integral and Sum.
"""
__slots__ = ()
def __new__(cls, function, *symbols, **assumptions):
from sympy.concrete.summations import Sum
pre = _common_new(cls, function, *symbols,
discrete=issubclass(cls, Sum), **assumptions)
if isinstance(pre, tuple):
function, limits, orientation = pre
else:
return pre
obj = Expr.__new__(cls, **assumptions)
arglist = [orientation*function] # orientation not used in ExprWithLimits
arglist.extend(limits)
obj._args = tuple(arglist)
obj.is_commutative = function.is_commutative # limits already checked
return obj
def _eval_adjoint(self):
if all(x.is_real for x in flatten(self.limits)):
return self.func(self.function.adjoint(), *self.limits)
return None
def _eval_conjugate(self):
if all(x.is_real for x in flatten(self.limits)):
return self.func(self.function.conjugate(), *self.limits)
return None
def _eval_transpose(self):
if all(x.is_real for x in flatten(self.limits)):
return self.func(self.function.transpose(), *self.limits)
return None
def _eval_factor(self, **hints):
if 1 == len(self.limits):
summand = self.function.factor(**hints)
if summand.is_Mul:
out = sift(summand.args, lambda w: w.is_commutative \
and not set(self.variables) & w.free_symbols)
return Mul(*out[True])*self.func(Mul(*out[False]), \
*self.limits)
else:
summand = self.func(self.function, *self.limits[0:-1]).factor()
if not summand.has(self.variables[-1]):
return self.func(1, [self.limits[-1]]).doit()*summand
elif isinstance(summand, Mul):
return self.func(summand, self.limits[-1]).factor()
return self
def _eval_expand_basic(self, **hints):
summand = self.function.expand(**hints)
force = hints.get('force', False)
if (summand.is_Add and (force or summand.is_commutative and
self.has_finite_limits is not False)):
return Add(*[self.func(i, *self.limits) for i in summand.args])
elif isinstance(summand, MatrixBase):
return summand.applyfunc(lambda x: self.func(x, *self.limits))
elif summand != self.function:
return self.func(summand, *self.limits)
return self
PK ]ZZZ�|��� � sympy/concrete/gosper.py"""Gosper's algorithm for hypergeometric summation. """
from sympy.core import S, Dummy, symbols
from sympy.polys import Poly, parallel_poly_from_expr, factor
from sympy.utilities.iterables import is_sequence
def gosper_normal(f, g, n, polys=True):
r"""
Compute the Gosper's normal form of ``f`` and ``g``.
Explanation
===========
Given relatively prime univariate polynomials ``f`` and ``g``,
rewrite their quotient to a normal form defined as follows:
.. math::
\frac{f(n)}{g(n)} = Z \cdot \frac{A(n) C(n+1)}{B(n) C(n)}
where ``Z`` is an arbitrary constant and ``A``, ``B``, ``C`` are
monic polynomials in ``n`` with the following properties:
1. `\gcd(A(n), B(n+h)) = 1 \forall h \in \mathbb{N}`
2. `\gcd(B(n), C(n+1)) = 1`
3. `\gcd(A(n), C(n)) = 1`
This normal form, or rational factorization in other words, is a
crucial step in Gosper's algorithm and in solving of difference
equations. It can be also used to decide if two hypergeometric
terms are similar or not.
This procedure will return a tuple containing elements of this
factorization in the form ``(Z*A, B, C)``.
Examples
========
>>> from sympy.concrete.gosper import gosper_normal
>>> from sympy.abc import n
>>> gosper_normal(4*n+5, 2*(4*n+1)*(2*n+3), n, polys=False)
(1/4, n + 3/2, n + 1/4)
"""
(p, q), opt = parallel_poly_from_expr(
(f, g), n, field=True, extension=True)
a, A = p.LC(), p.monic()
b, B = q.LC(), q.monic()
C, Z = A.one, a/b
h = Dummy('h')
D = Poly(n + h, n, h, domain=opt.domain)
R = A.resultant(B.compose(D))
roots = set(R.ground_roots().keys())
for r in set(roots):
if not r.is_Integer or r < 0:
roots.remove(r)
for i in sorted(roots):
d = A.gcd(B.shift(+i))
A = A.quo(d)
B = B.quo(d.shift(-i))
for j in range(1, i + 1):
C *= d.shift(-j)
A = A.mul_ground(Z)
if not polys:
A = A.as_expr()
B = B.as_expr()
C = C.as_expr()
return A, B, C
def gosper_term(f, n):
r"""
Compute Gosper's hypergeometric term for ``f``.
Explanation
===========
Suppose ``f`` is a hypergeometric term such that:
.. math::
s_n = \sum_{k=0}^{n-1} f_k
and `f_k` does not depend on `n`. Returns a hypergeometric
term `g_n` such that `g_{n+1} - g_n = f_n`.
Examples
========
>>> from sympy.concrete.gosper import gosper_term
>>> from sympy import factorial
>>> from sympy.abc import n
>>> gosper_term((4*n + 1)*factorial(n)/factorial(2*n + 1), n)
(-n - 1/2)/(n + 1/4)
"""
from sympy.simplify import hypersimp
r = hypersimp(f, n)
if r is None:
return None # 'f' is *not* a hypergeometric term
p, q = r.as_numer_denom()
A, B, C = gosper_normal(p, q, n)
B = B.shift(-1)
N = S(A.degree())
M = S(B.degree())
K = S(C.degree())
if (N != M) or (A.LC() != B.LC()):
D = {K - max(N, M)}
elif not N:
D = {K - N + 1, S.Zero}
else:
D = {K - N + 1, (B.nth(N - 1) - A.nth(N - 1))/A.LC()}
for d in set(D):
if not d.is_Integer or d < 0:
D.remove(d)
if not D:
return None # 'f(n)' is *not* Gosper-summable
d = max(D)
coeffs = symbols('c:%s' % (d + 1), cls=Dummy)
domain = A.get_domain().inject(*coeffs)
x = Poly(coeffs, n, domain=domain)
H = A*x.shift(1) - B*x - C
from sympy.solvers.solvers import solve
solution = solve(H.coeffs(), coeffs)
if solution is None:
return None # 'f(n)' is *not* Gosper-summable
x = x.as_expr().subs(solution)
for coeff in coeffs:
if coeff not in solution:
x = x.subs(coeff, 0)
if x.is_zero:
return None # 'f(n)' is *not* Gosper-summable
else:
return B.as_expr()*x/C.as_expr()
def gosper_sum(f, k):
r"""
Gosper's hypergeometric summation algorithm.
Explanation
===========
Given a hypergeometric term ``f`` such that:
.. math ::
s_n = \sum_{k=0}^{n-1} f_k
and `f(n)` does not depend on `n`, returns `g_{n} - g(0)` where
`g_{n+1} - g_n = f_n`, or ``None`` if `s_n` cannot be expressed
in closed form as a sum of hypergeometric terms.
Examples
========
>>> from sympy.concrete.gosper import gosper_sum
>>> from sympy import factorial
>>> from sympy.abc import n, k
>>> f = (4*k + 1)*factorial(k)/factorial(2*k + 1)
>>> gosper_sum(f, (k, 0, n))
(-factorial(n) + 2*factorial(2*n + 1))/factorial(2*n + 1)
>>> _.subs(n, 2) == sum(f.subs(k, i) for i in [0, 1, 2])
True
>>> gosper_sum(f, (k, 3, n))
(-60*factorial(n) + factorial(2*n + 1))/(60*factorial(2*n + 1))
>>> _.subs(n, 5) == sum(f.subs(k, i) for i in [3, 4, 5])
True
References
==========
.. [1] Marko Petkovsek, Herbert S. Wilf, Doron Zeilberger, A = B,
AK Peters, Ltd., Wellesley, MA, USA, 1997, pp. 73--100
"""
indefinite = False
if is_sequence(k):
k, a, b = k
else:
indefinite = True
g = gosper_term(f, k)
if g is None:
return None
if indefinite:
result = f*g
else:
result = (f*(g + 1)).subs(k, b) - (f*g).subs(k, a)
if result is S.NaN:
try:
result = (f*(g + 1)).limit(k, b) - (f*g).limit(k, a)
except NotImplementedError:
result = None
return factor(result)
PK ]ZZZ;ͭ @D @D sympy/concrete/guess.py"""Various algorithms for helping identifying numbers and sequences."""
from sympy.concrete.products import (Product, product)
from sympy.core import Function, S
from sympy.core.add import Add
from sympy.core.numbers import Integer, Rational
from sympy.core.symbol import Symbol, symbols
from sympy.core.sympify import sympify
from sympy.functions.elementary.exponential import exp
from sympy.functions.elementary.integers import floor
from sympy.integrals.integrals import integrate
from sympy.polys.polyfuncs import rational_interpolate as rinterp
from sympy.polys.polytools import lcm
from sympy.simplify.radsimp import denom
from sympy.utilities import public
@public
def find_simple_recurrence_vector(l):
"""
This function is used internally by other functions from the
sympy.concrete.guess module. While most users may want to rather use the
function find_simple_recurrence when looking for recurrence relations
among rational numbers, the current function may still be useful when
some post-processing has to be done.
Explanation
===========
The function returns a vector of length n when a recurrence relation of
order n is detected in the sequence of rational numbers v.
If the returned vector has a length 1, then the returned value is always
the list [0], which means that no relation has been found.
While the functions is intended to be used with rational numbers, it should
work for other kinds of real numbers except for some cases involving
quadratic numbers; for that reason it should be used with some caution when
the argument is not a list of rational numbers.
Examples
========
>>> from sympy.concrete.guess import find_simple_recurrence_vector
>>> from sympy import fibonacci
>>> find_simple_recurrence_vector([fibonacci(k) for k in range(12)])
[1, -1, -1]
See Also
========
See the function sympy.concrete.guess.find_simple_recurrence which is more
user-friendly.
"""
q1 = [0]
q2 = [1]
b, z = 0, len(l) >> 1
while len(q2) <= z:
while l[b]==0:
b += 1
if b == len(l):
c = 1
for x in q2:
c = lcm(c, denom(x))
if q2[0]*c < 0: c = -c
for k in range(len(q2)):
q2[k] = int(q2[k]*c)
return q2
a = S.One/l[b]
m = [a]
for k in range(b+1, len(l)):
m.append(-sum(l[j+1]*m[b-j-1] for j in range(b, k))*a)
l, m = m, [0] * max(len(q2), b+len(q1))
for k, q in enumerate(q2):
m[k] = a*q
for k, q in enumerate(q1):
m[k+b] += q
while m[-1]==0: m.pop() # because trailing zeros can occur
q1, q2, b = q2, m, 1
return [0]
@public
def find_simple_recurrence(v, A=Function('a'), N=Symbol('n')):
"""
Detects and returns a recurrence relation from a sequence of several integer
(or rational) terms. The name of the function in the returned expression is
'a' by default; the main variable is 'n' by default. The smallest index in
the returned expression is always n (and never n-1, n-2, etc.).
Examples
========
>>> from sympy.concrete.guess import find_simple_recurrence
>>> from sympy import fibonacci
>>> find_simple_recurrence([fibonacci(k) for k in range(12)])
-a(n) - a(n + 1) + a(n + 2)
>>> from sympy import Function, Symbol
>>> a = [1, 1, 1]
>>> for k in range(15): a.append(5*a[-1]-3*a[-2]+8*a[-3])
>>> find_simple_recurrence(a, A=Function('f'), N=Symbol('i'))
-8*f(i) + 3*f(i + 1) - 5*f(i + 2) + f(i + 3)
"""
p = find_simple_recurrence_vector(v)
n = len(p)
if n <= 1: return S.Zero
return Add(*[A(N+n-1-k)*p[k] for k in range(n)])
@public
def rationalize(x, maxcoeff=10000):
"""
Helps identifying a rational number from a float (or mpmath.mpf) value by
using a continued fraction. The algorithm stops as soon as a large partial
quotient is detected (greater than 10000 by default).
Examples
========
>>> from sympy.concrete.guess import rationalize
>>> from mpmath import cos, pi
>>> rationalize(cos(pi/3))
1/2
>>> from mpmath import mpf
>>> rationalize(mpf("0.333333333333333"))
1/3
While the function is rather intended to help 'identifying' rational
values, it may be used in some cases for approximating real numbers.
(Though other functions may be more relevant in that case.)
>>> rationalize(pi, maxcoeff = 250)
355/113
See Also
========
Several other methods can approximate a real number as a rational, like:
* fractions.Fraction.from_decimal
* fractions.Fraction.from_float
* mpmath.identify
* mpmath.pslq by using the following syntax: mpmath.pslq([x, 1])
* mpmath.findpoly by using the following syntax: mpmath.findpoly(x, 1)
* sympy.simplify.nsimplify (which is a more general function)
The main difference between the current function and all these variants is
that control focuses on magnitude of partial quotients here rather than on
global precision of the approximation. If the real is "known to be" a
rational number, the current function should be able to detect it correctly
with the default settings even when denominator is great (unless its
expansion contains unusually big partial quotients) which may occur
when studying sequences of increasing numbers. If the user cares more
on getting simple fractions, other methods may be more convenient.
"""
p0, p1 = 0, 1
q0, q1 = 1, 0
a = floor(x)
while a < maxcoeff or q1==0:
p = a*p1 + p0
q = a*q1 + q0
p0, p1 = p1, p
q0, q1 = q1, q
if x==a: break
x = 1/(x-a)
a = floor(x)
return sympify(p) / q
@public
def guess_generating_function_rational(v, X=Symbol('x')):
"""
Tries to "guess" a rational generating function for a sequence of rational
numbers v.
Examples
========
>>> from sympy.concrete.guess import guess_generating_function_rational
>>> from sympy import fibonacci
>>> l = [fibonacci(k) for k in range(5,15)]
>>> guess_generating_function_rational(l)
(3*x + 5)/(-x**2 - x + 1)
See Also
========
sympy.series.approximants
mpmath.pade
"""
# a) compute the denominator as q
q = find_simple_recurrence_vector(v)
n = len(q)
if n <= 1: return None
# b) compute the numerator as p
p = [sum(v[i-k]*q[k] for k in range(min(i+1, n)))
for i in range(len(v)>>1)]
return (sum(p[k]*X**k for k in range(len(p)))
/ sum(q[k]*X**k for k in range(n)))
@public
def guess_generating_function(v, X=Symbol('x'), types=['all'], maxsqrtn=2):
"""
Tries to "guess" a generating function for a sequence of rational numbers v.
Only a few patterns are implemented yet.
Explanation
===========
The function returns a dictionary where keys are the name of a given type of
generating function. Six types are currently implemented:
type | formal definition
-------+----------------------------------------------------------------
ogf | f(x) = Sum( a_k * x^k , k: 0..infinity )
egf | f(x) = Sum( a_k * x^k / k! , k: 0..infinity )
lgf | f(x) = Sum( (-1)^(k+1) a_k * x^k / k , k: 1..infinity )
| (with initial index being hold as 1 rather than 0)
hlgf | f(x) = Sum( a_k * x^k / k , k: 1..infinity )
| (with initial index being hold as 1 rather than 0)
lgdogf | f(x) = derivate( log(Sum( a_k * x^k, k: 0..infinity )), x)
lgdegf | f(x) = derivate( log(Sum( a_k * x^k / k!, k: 0..infinity )), x)
In order to spare time, the user can select only some types of generating
functions (default being ['all']). While forgetting to use a list in the
case of a single type may seem to work most of the time as in: types='ogf'
this (convenient) syntax may lead to unexpected extra results in some cases.
Discarding a type when calling the function does not mean that the type will
not be present in the returned dictionary; it only means that no extra
computation will be performed for that type, but the function may still add
it in the result when it can be easily converted from another type.
Two generating functions (lgdogf and lgdegf) are not even computed if the
initial term of the sequence is 0; it may be useful in that case to try
again after having removed the leading zeros.
Examples
========
>>> from sympy.concrete.guess import guess_generating_function as ggf
>>> ggf([k+1 for k in range(12)], types=['ogf', 'lgf', 'hlgf'])
{'hlgf': 1/(1 - x), 'lgf': 1/(x + 1), 'ogf': 1/(x**2 - 2*x + 1)}
>>> from sympy import sympify
>>> l = sympify("[3/2, 11/2, 0, -121/2, -363/2, 121]")
>>> ggf(l)
{'ogf': (x + 3/2)/(11*x**2 - 3*x + 1)}
>>> from sympy import fibonacci
>>> ggf([fibonacci(k) for k in range(5, 15)], types=['ogf'])
{'ogf': (3*x + 5)/(-x**2 - x + 1)}
>>> from sympy import factorial
>>> ggf([factorial(k) for k in range(12)], types=['ogf', 'egf', 'lgf'])
{'egf': 1/(1 - x)}
>>> ggf([k+1 for k in range(12)], types=['egf'])
{'egf': (x + 1)*exp(x), 'lgdegf': (x + 2)/(x + 1)}
N-th root of a rational function can also be detected (below is an example
coming from the sequence A108626 from https://oeis.org).
The greatest n-th root to be tested is specified as maxsqrtn (default 2).
>>> ggf([1, 2, 5, 14, 41, 124, 383, 1200, 3799, 12122, 38919])['ogf']
sqrt(1/(x**4 + 2*x**2 - 4*x + 1))
References
==========
.. [1] "Concrete Mathematics", R.L. Graham, D.E. Knuth, O. Patashnik
.. [2] https://oeis.org/wiki/Generating_functions
"""
# List of all types of all g.f. known by the algorithm
if 'all' in types:
types = ('ogf', 'egf', 'lgf', 'hlgf', 'lgdogf', 'lgdegf')
result = {}
# Ordinary Generating Function (ogf)
if 'ogf' in types:
# Perform some convolutions of the sequence with itself
t = [1] + [0]*(len(v) - 1)
for d in range(max(1, maxsqrtn)):
t = [sum(t[n-i]*v[i] for i in range(n+1)) for n in range(len(v))]
g = guess_generating_function_rational(t, X=X)
if g:
result['ogf'] = g**Rational(1, d+1)
break
# Exponential Generating Function (egf)
if 'egf' in types:
# Transform sequence (division by factorial)
w, f = [], S.One
for i, k in enumerate(v):
f *= i if i else 1
w.append(k/f)
# Perform some convolutions of the sequence with itself
t = [1] + [0]*(len(w) - 1)
for d in range(max(1, maxsqrtn)):
t = [sum(t[n-i]*w[i] for i in range(n+1)) for n in range(len(w))]
g = guess_generating_function_rational(t, X=X)
if g:
result['egf'] = g**Rational(1, d+1)
break
# Logarithmic Generating Function (lgf)
if 'lgf' in types:
# Transform sequence (multiplication by (-1)^(n+1) / n)
w, f = [], S.NegativeOne
for i, k in enumerate(v):
f = -f
w.append(f*k/Integer(i+1))
# Perform some convolutions of the sequence with itself
t = [1] + [0]*(len(w) - 1)
for d in range(max(1, maxsqrtn)):
t = [sum(t[n-i]*w[i] for i in range(n+1)) for n in range(len(w))]
g = guess_generating_function_rational(t, X=X)
if g:
result['lgf'] = g**Rational(1, d+1)
break
# Hyperbolic logarithmic Generating Function (hlgf)
if 'hlgf' in types:
# Transform sequence (division by n+1)
w = []
for i, k in enumerate(v):
w.append(k/Integer(i+1))
# Perform some convolutions of the sequence with itself
t = [1] + [0]*(len(w) - 1)
for d in range(max(1, maxsqrtn)):
t = [sum(t[n-i]*w[i] for i in range(n+1)) for n in range(len(w))]
g = guess_generating_function_rational(t, X=X)
if g:
result['hlgf'] = g**Rational(1, d+1)
break
# Logarithmic derivative of ordinary generating Function (lgdogf)
if v[0] != 0 and ('lgdogf' in types
or ('ogf' in types and 'ogf' not in result)):
# Transform sequence by computing f'(x)/f(x)
# because log(f(x)) = integrate( f'(x)/f(x) )
a, w = sympify(v[0]), []
for n in range(len(v)-1):
w.append(
(v[n+1]*(n+1) - sum(w[-i-1]*v[i+1] for i in range(n)))/a)
# Perform some convolutions of the sequence with itself
t = [1] + [0]*(len(w) - 1)
for d in range(max(1, maxsqrtn)):
t = [sum(t[n-i]*w[i] for i in range(n+1)) for n in range(len(w))]
g = guess_generating_function_rational(t, X=X)
if g:
result['lgdogf'] = g**Rational(1, d+1)
if 'ogf' not in result:
result['ogf'] = exp(integrate(result['lgdogf'], X))
break
# Logarithmic derivative of exponential generating Function (lgdegf)
if v[0] != 0 and ('lgdegf' in types
or ('egf' in types and 'egf' not in result)):
# Transform sequence / step 1 (division by factorial)
z, f = [], S.One
for i, k in enumerate(v):
f *= i if i else 1
z.append(k/f)
# Transform sequence / step 2 by computing f'(x)/f(x)
# because log(f(x)) = integrate( f'(x)/f(x) )
a, w = z[0], []
for n in range(len(z)-1):
w.append(
(z[n+1]*(n+1) - sum(w[-i-1]*z[i+1] for i in range(n)))/a)
# Perform some convolutions of the sequence with itself
t = [1] + [0]*(len(w) - 1)
for d in range(max(1, maxsqrtn)):
t = [sum(t[n-i]*w[i] for i in range(n+1)) for n in range(len(w))]
g = guess_generating_function_rational(t, X=X)
if g:
result['lgdegf'] = g**Rational(1, d+1)
if 'egf' not in result:
result['egf'] = exp(integrate(result['lgdegf'], X))
break
return result
@public
def guess(l, all=False, evaluate=True, niter=2, variables=None):
"""
This function is adapted from the Rate.m package for Mathematica
written by Christian Krattenthaler.
It tries to guess a formula from a given sequence of rational numbers.
Explanation
===========
In order to speed up the process, the 'all' variable is set to False by
default, stopping the computation as some results are returned during an
iteration; the variable can be set to True if more iterations are needed
(other formulas may be found; however they may be equivalent to the first
ones).
Another option is the 'evaluate' variable (default is True); setting it
to False will leave the involved products unevaluated.
By default, the number of iterations is set to 2 but a greater value (up
to len(l)-1) can be specified with the optional 'niter' variable.
More and more convoluted results are found when the order of the
iteration gets higher:
* first iteration returns polynomial or rational functions;
* second iteration returns products of rising factorials and their
inverses;
* third iteration returns products of products of rising factorials
and their inverses;
* etc.
The returned formulas contain symbols i0, i1, i2, ... where the main
variables is i0 (and auxiliary variables are i1, i2, ...). A list of
other symbols can be provided in the 'variables' option; the length of
the least should be the value of 'niter' (more is acceptable but only
the first symbols will be used); in this case, the main variable will be
the first symbol in the list.
Examples
========
>>> from sympy.concrete.guess import guess
>>> guess([1,2,6,24,120], evaluate=False)
[Product(i1 + 1, (i1, 1, i0 - 1))]
>>> from sympy import symbols
>>> r = guess([1,2,7,42,429,7436,218348,10850216], niter=4)
>>> i0 = symbols("i0")
>>> [r[0].subs(i0,n).doit() for n in range(1,10)]
[1, 2, 7, 42, 429, 7436, 218348, 10850216, 911835460]
"""
if any(a==0 for a in l[:-1]):
return []
N = len(l)
niter = min(N-1, niter)
myprod = product if evaluate else Product
g = []
res = []
if variables is None:
symb = symbols('i:'+str(niter))
else:
symb = variables
for k, s in enumerate(symb):
g.append(l)
n, r = len(l), []
for i in range(n-2-1, -1, -1):
ri = rinterp(enumerate(g[k][:-1], start=1), i, X=s)
if ((denom(ri).subs({s:n}) != 0)
and (ri.subs({s:n}) - g[k][-1] == 0)
and ri not in r):
r.append(ri)
if r:
for i in range(k-1, -1, -1):
r = [g[i][0]
* myprod(v, (symb[i+1], 1, symb[i]-1)) for v in r]
if not all: return r
res += r
l = [Rational(l[i+1], l[i]) for i in range(N-k-1)]
return res
PK ]ZZZs�%��H �H sympy/concrete/products.pyfrom typing import Tuple as tTuple
from .expr_with_intlimits import ExprWithIntLimits
from .summations import Sum, summation, _dummy_with_inherited_properties_concrete
from sympy.core.expr import Expr
from sympy.core.exprtools import factor_terms
from sympy.core.function import Derivative
from sympy.core.mul import Mul
from sympy.core.singleton import S
from sympy.core.symbol import Dummy, Symbol
from sympy.functions.combinatorial.factorials import RisingFactorial
from sympy.functions.elementary.exponential import exp, log
from sympy.functions.special.tensor_functions import KroneckerDelta
from sympy.polys import quo, roots
class Product(ExprWithIntLimits):
r"""
Represents unevaluated products.
Explanation
===========
``Product`` represents a finite or infinite product, with the first
argument being the general form of terms in the series, and the second
argument being ``(dummy_variable, start, end)``, with ``dummy_variable``
taking all integer values from ``start`` through ``end``. In accordance
with long-standing mathematical convention, the end term is included in
the product.
Finite products
===============
For finite products (and products with symbolic limits assumed to be finite)
we follow the analogue of the summation convention described by Karr [1],
especially definition 3 of section 1.4. The product:
.. math::
\prod_{m \leq i < n} f(i)
has *the obvious meaning* for `m < n`, namely:
.. math::
\prod_{m \leq i < n} f(i) = f(m) f(m+1) \cdot \ldots \cdot f(n-2) f(n-1)
with the upper limit value `f(n)` excluded. The product over an empty set is
one if and only if `m = n`:
.. math::
\prod_{m \leq i < n} f(i) = 1 \quad \mathrm{for} \quad m = n
Finally, for all other products over empty sets we assume the following
definition:
.. math::
\prod_{m \leq i < n} f(i) = \frac{1}{\prod_{n \leq i < m} f(i)} \quad \mathrm{for} \quad m > n
It is important to note that above we define all products with the upper
limit being exclusive. This is in contrast to the usual mathematical notation,
but does not affect the product convention. Indeed we have:
.. math::
\prod_{m \leq i < n} f(i) = \prod_{i = m}^{n - 1} f(i)
where the difference in notation is intentional to emphasize the meaning,
with limits typeset on the top being inclusive.
Examples
========
>>> from sympy.abc import a, b, i, k, m, n, x
>>> from sympy import Product, oo
>>> Product(k, (k, 1, m))
Product(k, (k, 1, m))
>>> Product(k, (k, 1, m)).doit()
factorial(m)
>>> Product(k**2,(k, 1, m))
Product(k**2, (k, 1, m))
>>> Product(k**2,(k, 1, m)).doit()
factorial(m)**2
Wallis' product for pi:
>>> W = Product(2*i/(2*i-1) * 2*i/(2*i+1), (i, 1, oo))
>>> W
Product(4*i**2/((2*i - 1)*(2*i + 1)), (i, 1, oo))
Direct computation currently fails:
>>> W.doit()
Product(4*i**2/((2*i - 1)*(2*i + 1)), (i, 1, oo))
But we can approach the infinite product by a limit of finite products:
>>> from sympy import limit
>>> W2 = Product(2*i/(2*i-1)*2*i/(2*i+1), (i, 1, n))
>>> W2
Product(4*i**2/((2*i - 1)*(2*i + 1)), (i, 1, n))
>>> W2e = W2.doit()
>>> W2e
4**n*factorial(n)**2/(2**(2*n)*RisingFactorial(1/2, n)*RisingFactorial(3/2, n))
>>> limit(W2e, n, oo)
pi/2
By the same formula we can compute sin(pi/2):
>>> from sympy import combsimp, pi, gamma, simplify
>>> P = pi * x * Product(1 - x**2/k**2, (k, 1, n))
>>> P = P.subs(x, pi/2)
>>> P
pi**2*Product(1 - pi**2/(4*k**2), (k, 1, n))/2
>>> Pe = P.doit()
>>> Pe
pi**2*RisingFactorial(1 - pi/2, n)*RisingFactorial(1 + pi/2, n)/(2*factorial(n)**2)
>>> limit(Pe, n, oo).gammasimp()
sin(pi**2/2)
>>> Pe.rewrite(gamma)
(-1)**n*pi**2*gamma(pi/2)*gamma(n + 1 + pi/2)/(2*gamma(1 + pi/2)*gamma(-n + pi/2)*gamma(n + 1)**2)
Products with the lower limit being larger than the upper one:
>>> Product(1/i, (i, 6, 1)).doit()
120
>>> Product(i, (i, 2, 5)).doit()
120
The empty product:
>>> Product(i, (i, n, n-1)).doit()
1
An example showing that the symbolic result of a product is still
valid for seemingly nonsensical values of the limits. Then the Karr
convention allows us to give a perfectly valid interpretation to
those products by interchanging the limits according to the above rules:
>>> P = Product(2, (i, 10, n)).doit()
>>> P
2**(n - 9)
>>> P.subs(n, 5)
1/16
>>> Product(2, (i, 10, 5)).doit()
1/16
>>> 1/Product(2, (i, 6, 9)).doit()
1/16
An explicit example of the Karr summation convention applied to products:
>>> P1 = Product(x, (i, a, b)).doit()
>>> P1
x**(-a + b + 1)
>>> P2 = Product(x, (i, b+1, a-1)).doit()
>>> P2
x**(a - b - 1)
>>> simplify(P1 * P2)
1
And another one:
>>> P1 = Product(i, (i, b, a)).doit()
>>> P1
RisingFactorial(b, a - b + 1)
>>> P2 = Product(i, (i, a+1, b-1)).doit()
>>> P2
RisingFactorial(a + 1, -a + b - 1)
>>> P1 * P2
RisingFactorial(b, a - b + 1)*RisingFactorial(a + 1, -a + b - 1)
>>> combsimp(P1 * P2)
1
See Also
========
Sum, summation
product
References
==========
.. [1] Michael Karr, "Summation in Finite Terms", Journal of the ACM,
Volume 28 Issue 2, April 1981, Pages 305-350
https://dl.acm.org/doi/10.1145/322248.322255
.. [2] https://en.wikipedia.org/wiki/Multiplication#Capital_Pi_notation
.. [3] https://en.wikipedia.org/wiki/Empty_product
"""
__slots__ = ()
limits: tTuple[tTuple[Symbol, Expr, Expr]]
def __new__(cls, function, *symbols, **assumptions):
obj = ExprWithIntLimits.__new__(cls, function, *symbols, **assumptions)
return obj
def _eval_rewrite_as_Sum(self, *args, **kwargs):
return exp(Sum(log(self.function), *self.limits))
@property
def term(self):
return self._args[0]
function = term
def _eval_is_zero(self):
if self.has_empty_sequence:
return False
z = self.term.is_zero
if z is True:
return True
if self.has_finite_limits:
# A Product is zero only if its term is zero assuming finite limits.
return z
def _eval_is_extended_real(self):
if self.has_empty_sequence:
return True
return self.function.is_extended_real
def _eval_is_positive(self):
if self.has_empty_sequence:
return True
if self.function.is_positive and self.has_finite_limits:
return True
def _eval_is_nonnegative(self):
if self.has_empty_sequence:
return True
if self.function.is_nonnegative and self.has_finite_limits:
return True
def _eval_is_extended_nonnegative(self):
if self.has_empty_sequence:
return True
if self.function.is_extended_nonnegative:
return True
def _eval_is_extended_nonpositive(self):
if self.has_empty_sequence:
return True
def _eval_is_finite(self):
if self.has_finite_limits and self.function.is_finite:
return True
def doit(self, **hints):
# first make sure any definite limits have product
# variables with matching assumptions
reps = {}
for xab in self.limits:
d = _dummy_with_inherited_properties_concrete(xab)
if d:
reps[xab[0]] = d
if reps:
undo = {v: k for k, v in reps.items()}
did = self.xreplace(reps).doit(**hints)
if isinstance(did, tuple): # when separate=True
did = tuple([i.xreplace(undo) for i in did])
else:
did = did.xreplace(undo)
return did
from sympy.simplify.powsimp import powsimp
f = self.function
for index, limit in enumerate(self.limits):
i, a, b = limit
dif = b - a
if dif.is_integer and dif.is_negative:
a, b = b + 1, a - 1
f = 1 / f
g = self._eval_product(f, (i, a, b))
if g in (None, S.NaN):
return self.func(powsimp(f), *self.limits[index:])
else:
f = g
if hints.get('deep', True):
return f.doit(**hints)
else:
return powsimp(f)
def _eval_adjoint(self):
if self.is_commutative:
return self.func(self.function.adjoint(), *self.limits)
return None
def _eval_conjugate(self):
return self.func(self.function.conjugate(), *self.limits)
def _eval_product(self, term, limits):
(k, a, n) = limits
if k not in term.free_symbols:
if (term - 1).is_zero:
return S.One
return term**(n - a + 1)
if a == n:
return term.subs(k, a)
from .delta import deltaproduct, _has_simple_delta
if term.has(KroneckerDelta) and _has_simple_delta(term, limits[0]):
return deltaproduct(term, limits)
dif = n - a
definite = dif.is_Integer
if definite and (dif < 100):
return self._eval_product_direct(term, limits)
elif term.is_polynomial(k):
poly = term.as_poly(k)
A = B = Q = S.One
all_roots = roots(poly)
M = 0
for r, m in all_roots.items():
M += m
A *= RisingFactorial(a - r, n - a + 1)**m
Q *= (n - r)**m
if M < poly.degree():
arg = quo(poly, Q.as_poly(k))
B = self.func(arg, (k, a, n)).doit()
return poly.LC()**(n - a + 1) * A * B
elif term.is_Add:
factored = factor_terms(term, fraction=True)
if factored.is_Mul:
return self._eval_product(factored, (k, a, n))
elif term.is_Mul:
# Factor in part without the summation variable and part with
without_k, with_k = term.as_coeff_mul(k)
if len(with_k) >= 2:
# More than one term including k, so still a multiplication
exclude, include = [], []
for t in with_k:
p = self._eval_product(t, (k, a, n))
if p is not None:
exclude.append(p)
else:
include.append(t)
if not exclude:
return None
else:
arg = term._new_rawargs(*include)
A = Mul(*exclude)
B = self.func(arg, (k, a, n)).doit()
return without_k**(n - a + 1)*A * B
else:
# Just a single term
p = self._eval_product(with_k[0], (k, a, n))
if p is None:
p = self.func(with_k[0], (k, a, n)).doit()
return without_k**(n - a + 1)*p
elif term.is_Pow:
if not term.base.has(k):
s = summation(term.exp, (k, a, n))
return term.base**s
elif not term.exp.has(k):
p = self._eval_product(term.base, (k, a, n))
if p is not None:
return p**term.exp
elif isinstance(term, Product):
evaluated = term.doit()
f = self._eval_product(evaluated, limits)
if f is None:
return self.func(evaluated, limits)
else:
return f
if definite:
return self._eval_product_direct(term, limits)
def _eval_simplify(self, **kwargs):
from sympy.simplify.simplify import product_simplify
rv = product_simplify(self, **kwargs)
return rv.doit() if kwargs['doit'] else rv
def _eval_transpose(self):
if self.is_commutative:
return self.func(self.function.transpose(), *self.limits)
return None
def _eval_product_direct(self, term, limits):
(k, a, n) = limits
return Mul(*[term.subs(k, a + i) for i in range(n - a + 1)])
def _eval_derivative(self, x):
if isinstance(x, Symbol) and x not in self.free_symbols:
return S.Zero
f, limits = self.function, list(self.limits)
limit = limits.pop(-1)
if limits:
f = self.func(f, *limits)
i, a, b = limit
if x in a.free_symbols or x in b.free_symbols:
return None
h = Dummy()
rv = Sum( Product(f, (i, a, h - 1)) * Product(f, (i, h + 1, b)) * Derivative(f, x, evaluate=True).subs(i, h), (h, a, b))
return rv
def is_convergent(self):
r"""
See docs of :obj:`.Sum.is_convergent()` for explanation of convergence
in SymPy.
Explanation
===========
The infinite product:
.. math::
\prod_{1 \leq i < \infty} f(i)
is defined by the sequence of partial products:
.. math::
\prod_{i=1}^{n} f(i) = f(1) f(2) \cdots f(n)
as n increases without bound. The product converges to a non-zero
value if and only if the sum:
.. math::
\sum_{1 \leq i < \infty} \log{f(n)}
converges.
Examples
========
>>> from sympy import Product, Symbol, cos, pi, exp, oo
>>> n = Symbol('n', integer=True)
>>> Product(n/(n + 1), (n, 1, oo)).is_convergent()
False
>>> Product(1/n**2, (n, 1, oo)).is_convergent()
False
>>> Product(cos(pi/n), (n, 1, oo)).is_convergent()
True
>>> Product(exp(-n**2), (n, 1, oo)).is_convergent()
False
References
==========
.. [1] https://en.wikipedia.org/wiki/Infinite_product
"""
sequence_term = self.function
log_sum = log(sequence_term)
lim = self.limits
try:
is_conv = Sum(log_sum, *lim).is_convergent()
except NotImplementedError:
if Sum(sequence_term - 1, *lim).is_absolutely_convergent() is S.true:
return S.true
raise NotImplementedError("The algorithm to find the product convergence of %s "
"is not yet implemented" % (sequence_term))
return is_conv
def reverse_order(expr, *indices):
"""
Reverse the order of a limit in a Product.
Explanation
===========
``reverse_order(expr, *indices)`` reverses some limits in the expression
``expr`` which can be either a ``Sum`` or a ``Product``. The selectors in
the argument ``indices`` specify some indices whose limits get reversed.
These selectors are either variable names or numerical indices counted
starting from the inner-most limit tuple.
Examples
========
>>> from sympy import gamma, Product, simplify, Sum
>>> from sympy.abc import x, y, a, b, c, d
>>> P = Product(x, (x, a, b))
>>> Pr = P.reverse_order(x)
>>> Pr
Product(1/x, (x, b + 1, a - 1))
>>> Pr = Pr.doit()
>>> Pr
1/RisingFactorial(b + 1, a - b - 1)
>>> simplify(Pr.rewrite(gamma))
Piecewise((gamma(b + 1)/gamma(a), b > -1), ((-1)**(-a + b + 1)*gamma(1 - a)/gamma(-b), True))
>>> P = P.doit()
>>> P
RisingFactorial(a, -a + b + 1)
>>> simplify(P.rewrite(gamma))
Piecewise((gamma(b + 1)/gamma(a), a > 0), ((-1)**(-a + b + 1)*gamma(1 - a)/gamma(-b), True))
While one should prefer variable names when specifying which limits
to reverse, the index counting notation comes in handy in case there
are several symbols with the same name.
>>> S = Sum(x*y, (x, a, b), (y, c, d))
>>> S
Sum(x*y, (x, a, b), (y, c, d))
>>> S0 = S.reverse_order(0)
>>> S0
Sum(-x*y, (x, b + 1, a - 1), (y, c, d))
>>> S1 = S0.reverse_order(1)
>>> S1
Sum(x*y, (x, b + 1, a - 1), (y, d + 1, c - 1))
Of course we can mix both notations:
>>> Sum(x*y, (x, a, b), (y, 2, 5)).reverse_order(x, 1)
Sum(x*y, (x, b + 1, a - 1), (y, 6, 1))
>>> Sum(x*y, (x, a, b), (y, 2, 5)).reverse_order(y, x)
Sum(x*y, (x, b + 1, a - 1), (y, 6, 1))
See Also
========
sympy.concrete.expr_with_intlimits.ExprWithIntLimits.index,
reorder_limit,
sympy.concrete.expr_with_intlimits.ExprWithIntLimits.reorder
References
==========
.. [1] Michael Karr, "Summation in Finite Terms", Journal of the ACM,
Volume 28 Issue 2, April 1981, Pages 305-350
https://dl.acm.org/doi/10.1145/322248.322255
"""
l_indices = list(indices)
for i, indx in enumerate(l_indices):
if not isinstance(indx, int):
l_indices[i] = expr.index(indx)
e = 1
limits = []
for i, limit in enumerate(expr.limits):
l = limit
if i in l_indices:
e = -e
l = (limit[0], limit[2] + 1, limit[1] - 1)
limits.append(l)
return Product(expr.function ** e, *limits)
def product(*args, **kwargs):
r"""
Compute the product.
Explanation
===========
The notation for symbols is similar to the notation used in Sum or
Integral. product(f, (i, a, b)) computes the product of f with
respect to i from a to b, i.e.,
::
b
_____
product(f(n), (i, a, b)) = | | f(n)
| |
i = a
If it cannot compute the product, it returns an unevaluated Product object.
Repeated products can be computed by introducing additional symbols tuples::
Examples
========
>>> from sympy import product, symbols
>>> i, n, m, k = symbols('i n m k', integer=True)
>>> product(i, (i, 1, k))
factorial(k)
>>> product(m, (i, 1, k))
m**k
>>> product(i, (i, 1, k), (k, 1, n))
Product(factorial(k), (k, 1, n))
"""
prod = Product(*args, **kwargs)
if isinstance(prod, Product):
return prod.doit(deep=False)
else:
return prod
PK ]ZZZZ�7=� =� sympy/concrete/summations.pyfrom typing import Tuple as tTuple
from sympy.calculus.singularities import is_decreasing
from sympy.calculus.accumulationbounds import AccumulationBounds
from .expr_with_intlimits import ExprWithIntLimits
from .expr_with_limits import AddWithLimits
from .gosper import gosper_sum
from sympy.core.expr import Expr
from sympy.core.add import Add
from sympy.core.containers import Tuple
from sympy.core.function import Derivative, expand
from sympy.core.mul import Mul
from sympy.core.numbers import Float, _illegal
from sympy.core.relational import Eq
from sympy.core.singleton import S
from sympy.core.sorting import ordered
from sympy.core.symbol import Dummy, Wild, Symbol, symbols
from sympy.functions.combinatorial.factorials import factorial
from sympy.functions.combinatorial.numbers import bernoulli, harmonic
from sympy.functions.elementary.exponential import exp, log
from sympy.functions.elementary.piecewise import Piecewise
from sympy.functions.elementary.trigonometric import cot, csc
from sympy.functions.special.hyper import hyper
from sympy.functions.special.tensor_functions import KroneckerDelta
from sympy.functions.special.zeta_functions import zeta
from sympy.integrals.integrals import Integral
from sympy.logic.boolalg import And
from sympy.polys.partfrac import apart
from sympy.polys.polyerrors import PolynomialError, PolificationFailed
from sympy.polys.polytools import parallel_poly_from_expr, Poly, factor
from sympy.polys.rationaltools import together
from sympy.series.limitseq import limit_seq
from sympy.series.order import O
from sympy.series.residues import residue
from sympy.sets.sets import FiniteSet, Interval
from sympy.utilities.iterables import sift
import itertools
class Sum(AddWithLimits, ExprWithIntLimits):
r"""
Represents unevaluated summation.
Explanation
===========
``Sum`` represents a finite or infinite series, with the first argument
being the general form of terms in the series, and the second argument
being ``(dummy_variable, start, end)``, with ``dummy_variable`` taking
all integer values from ``start`` through ``end``. In accordance with
long-standing mathematical convention, the end term is included in the
summation.
Finite sums
===========
For finite sums (and sums with symbolic limits assumed to be finite) we
follow the summation convention described by Karr [1], especially
definition 3 of section 1.4. The sum:
.. math::
\sum_{m \leq i < n} f(i)
has *the obvious meaning* for `m < n`, namely:
.. math::
\sum_{m \leq i < n} f(i) = f(m) + f(m+1) + \ldots + f(n-2) + f(n-1)
with the upper limit value `f(n)` excluded. The sum over an empty set is
zero if and only if `m = n`:
.. math::
\sum_{m \leq i < n} f(i) = 0 \quad \mathrm{for} \quad m = n
Finally, for all other sums over empty sets we assume the following
definition:
.. math::
\sum_{m \leq i < n} f(i) = - \sum_{n \leq i < m} f(i) \quad \mathrm{for} \quad m > n
It is important to note that Karr defines all sums with the upper
limit being exclusive. This is in contrast to the usual mathematical notation,
but does not affect the summation convention. Indeed we have:
.. math::
\sum_{m \leq i < n} f(i) = \sum_{i = m}^{n - 1} f(i)
where the difference in notation is intentional to emphasize the meaning,
with limits typeset on the top being inclusive.
Examples
========
>>> from sympy.abc import i, k, m, n, x
>>> from sympy import Sum, factorial, oo, IndexedBase, Function
>>> Sum(k, (k, 1, m))
Sum(k, (k, 1, m))
>>> Sum(k, (k, 1, m)).doit()
m**2/2 + m/2
>>> Sum(k**2, (k, 1, m))
Sum(k**2, (k, 1, m))
>>> Sum(k**2, (k, 1, m)).doit()
m**3/3 + m**2/2 + m/6
>>> Sum(x**k, (k, 0, oo))
Sum(x**k, (k, 0, oo))
>>> Sum(x**k, (k, 0, oo)).doit()
Piecewise((1/(1 - x), Abs(x) < 1), (Sum(x**k, (k, 0, oo)), True))
>>> Sum(x**k/factorial(k), (k, 0, oo)).doit()
exp(x)
Here are examples to do summation with symbolic indices. You
can use either Function of IndexedBase classes:
>>> f = Function('f')
>>> Sum(f(n), (n, 0, 3)).doit()
f(0) + f(1) + f(2) + f(3)
>>> Sum(f(n), (n, 0, oo)).doit()
Sum(f(n), (n, 0, oo))
>>> f = IndexedBase('f')
>>> Sum(f[n]**2, (n, 0, 3)).doit()
f[0]**2 + f[1]**2 + f[2]**2 + f[3]**2
An example showing that the symbolic result of a summation is still
valid for seemingly nonsensical values of the limits. Then the Karr
convention allows us to give a perfectly valid interpretation to
those sums by interchanging the limits according to the above rules:
>>> S = Sum(i, (i, 1, n)).doit()
>>> S
n**2/2 + n/2
>>> S.subs(n, -4)
6
>>> Sum(i, (i, 1, -4)).doit()
6
>>> Sum(-i, (i, -3, 0)).doit()
6
An explicit example of the Karr summation convention:
>>> S1 = Sum(i**2, (i, m, m+n-1)).doit()
>>> S1
m**2*n + m*n**2 - m*n + n**3/3 - n**2/2 + n/6
>>> S2 = Sum(i**2, (i, m+n, m-1)).doit()
>>> S2
-m**2*n - m*n**2 + m*n - n**3/3 + n**2/2 - n/6
>>> S1 + S2
0
>>> S3 = Sum(i, (i, m, m-1)).doit()
>>> S3
0
See Also
========
summation
Product, sympy.concrete.products.product
References
==========
.. [1] Michael Karr, "Summation in Finite Terms", Journal of the ACM,
Volume 28 Issue 2, April 1981, Pages 305-350
https://dl.acm.org/doi/10.1145/322248.322255
.. [2] https://en.wikipedia.org/wiki/Summation#Capital-sigma_notation
.. [3] https://en.wikipedia.org/wiki/Empty_sum
"""
__slots__ = ()
limits: tTuple[tTuple[Symbol, Expr, Expr]]
def __new__(cls, function, *symbols, **assumptions):
obj = AddWithLimits.__new__(cls, function, *symbols, **assumptions)
if not hasattr(obj, 'limits'):
return obj
if any(len(l) != 3 or None in l for l in obj.limits):
raise ValueError('Sum requires values for lower and upper bounds.')
return obj
def _eval_is_zero(self):
# a Sum is only zero if its function is zero or if all terms
# cancel out. This only answers whether the summand is zero; if
# not then None is returned since we don't analyze whether all
# terms cancel out.
if self.function.is_zero or self.has_empty_sequence:
return True
def _eval_is_extended_real(self):
if self.has_empty_sequence:
return True
return self.function.is_extended_real
def _eval_is_positive(self):
if self.has_finite_limits and self.has_reversed_limits is False:
return self.function.is_positive
def _eval_is_negative(self):
if self.has_finite_limits and self.has_reversed_limits is False:
return self.function.is_negative
def _eval_is_finite(self):
if self.has_finite_limits and self.function.is_finite:
return True
def doit(self, **hints):
if hints.get('deep', True):
f = self.function.doit(**hints)
else:
f = self.function
# first make sure any definite limits have summation
# variables with matching assumptions
reps = {}
for xab in self.limits:
d = _dummy_with_inherited_properties_concrete(xab)
if d:
reps[xab[0]] = d
if reps:
undo = {v: k for k, v in reps.items()}
did = self.xreplace(reps).doit(**hints)
if isinstance(did, tuple): # when separate=True
did = tuple([i.xreplace(undo) for i in did])
elif did is not None:
did = did.xreplace(undo)
else:
did = self
return did
if self.function.is_Matrix:
expanded = self.expand()
if self != expanded:
return expanded.doit()
return _eval_matrix_sum(self)
for n, limit in enumerate(self.limits):
i, a, b = limit
dif = b - a
if dif == -1:
# Any summation over an empty set is zero
return S.Zero
if dif.is_integer and dif.is_negative:
a, b = b + 1, a - 1
f = -f
newf = eval_sum(f, (i, a, b))
if newf is None:
if f == self.function:
zeta_function = self.eval_zeta_function(f, (i, a, b))
if zeta_function is not None:
return zeta_function
return self
else:
return self.func(f, *self.limits[n:])
f = newf
if hints.get('deep', True):
# eval_sum could return partially unevaluated
# result with Piecewise. In this case we won't
# doit() recursively.
if not isinstance(f, Piecewise):
return f.doit(**hints)
return f
def eval_zeta_function(self, f, limits):
"""
Check whether the function matches with the zeta function.
If it matches, then return a `Piecewise` expression because
zeta function does not converge unless `s > 1` and `q > 0`
"""
i, a, b = limits
w, y, z = Wild('w', exclude=[i]), Wild('y', exclude=[i]), Wild('z', exclude=[i])
result = f.match((w * i + y) ** (-z))
if result is not None and b is S.Infinity:
coeff = 1 / result[w] ** result[z]
s = result[z]
q = result[y] / result[w] + a
return Piecewise((coeff * zeta(s, q), And(q > 0, s > 1)), (self, True))
def _eval_derivative(self, x):
"""
Differentiate wrt x as long as x is not in the free symbols of any of
the upper or lower limits.
Explanation
===========
Sum(a*b*x, (x, 1, a)) can be differentiated wrt x or b but not `a`
since the value of the sum is discontinuous in `a`. In a case
involving a limit variable, the unevaluated derivative is returned.
"""
# diff already confirmed that x is in the free symbols of self, but we
# don't want to differentiate wrt any free symbol in the upper or lower
# limits
# XXX remove this test for free_symbols when the default _eval_derivative is in
if isinstance(x, Symbol) and x not in self.free_symbols:
return S.Zero
# get limits and the function
f, limits = self.function, list(self.limits)
limit = limits.pop(-1)
if limits: # f is the argument to a Sum
f = self.func(f, *limits)
_, a, b = limit
if x in a.free_symbols or x in b.free_symbols:
return None
df = Derivative(f, x, evaluate=True)
rv = self.func(df, limit)
return rv
def _eval_difference_delta(self, n, step):
k, _, upper = self.args[-1]
new_upper = upper.subs(n, n + step)
if len(self.args) == 2:
f = self.args[0]
else:
f = self.func(*self.args[:-1])
return Sum(f, (k, upper + 1, new_upper)).doit()
def _eval_simplify(self, **kwargs):
function = self.function
if kwargs.get('deep', True):
function = function.simplify(**kwargs)
# split the function into adds
terms = Add.make_args(expand(function))
s_t = [] # Sum Terms
o_t = [] # Other Terms
for term in terms:
if term.has(Sum):
# if there is an embedded sum here
# it is of the form x * (Sum(whatever))
# hence we make a Mul out of it, and simplify all interior sum terms
subterms = Mul.make_args(expand(term))
out_terms = []
for subterm in subterms:
# go through each term
if isinstance(subterm, Sum):
# if it's a sum, simplify it
out_terms.append(subterm._eval_simplify(**kwargs))
else:
# otherwise, add it as is
out_terms.append(subterm)
# turn it back into a Mul
s_t.append(Mul(*out_terms))
else:
o_t.append(term)
# next try to combine any interior sums for further simplification
from sympy.simplify.simplify import factor_sum, sum_combine
result = Add(sum_combine(s_t), *o_t)
return factor_sum(result, limits=self.limits)
def is_convergent(self):
r"""
Checks for the convergence of a Sum.
Explanation
===========
We divide the study of convergence of infinite sums and products in
two parts.
First Part:
One part is the question whether all the terms are well defined, i.e.,
they are finite in a sum and also non-zero in a product. Zero
is the analogy of (minus) infinity in products as
:math:`e^{-\infty} = 0`.
Second Part:
The second part is the question of convergence after infinities,
and zeros in products, have been omitted assuming that their number
is finite. This means that we only consider the tail of the sum or
product, starting from some point after which all terms are well
defined.
For example, in a sum of the form:
.. math::
\sum_{1 \leq i < \infty} \frac{1}{n^2 + an + b}
where a and b are numbers. The routine will return true, even if there
are infinities in the term sequence (at most two). An analogous
product would be:
.. math::
\prod_{1 \leq i < \infty} e^{\frac{1}{n^2 + an + b}}
This is how convergence is interpreted. It is concerned with what
happens at the limit. Finding the bad terms is another independent
matter.
Note: It is responsibility of user to see that the sum or product
is well defined.
There are various tests employed to check the convergence like
divergence test, root test, integral test, alternating series test,
comparison tests, Dirichlet tests. It returns true if Sum is convergent
and false if divergent and NotImplementedError if it cannot be checked.
References
==========
.. [1] https://en.wikipedia.org/wiki/Convergence_tests
Examples
========
>>> from sympy import factorial, S, Sum, Symbol, oo
>>> n = Symbol('n', integer=True)
>>> Sum(n/(n - 1), (n, 4, 7)).is_convergent()
True
>>> Sum(n/(2*n + 1), (n, 1, oo)).is_convergent()
False
>>> Sum(factorial(n)/5**n, (n, 1, oo)).is_convergent()
False
>>> Sum(1/n**(S(6)/5), (n, 1, oo)).is_convergent()
True
See Also
========
Sum.is_absolutely_convergent
sympy.concrete.products.Product.is_convergent
"""
p, q, r = symbols('p q r', cls=Wild)
sym = self.limits[0][0]
lower_limit = self.limits[0][1]
upper_limit = self.limits[0][2]
sequence_term = self.function.simplify()
if len(sequence_term.free_symbols) > 1:
raise NotImplementedError("convergence checking for more than one symbol "
"containing series is not handled")
if lower_limit.is_finite and upper_limit.is_finite:
return S.true
# transform sym -> -sym and swap the upper_limit = S.Infinity
# and lower_limit = - upper_limit
if lower_limit is S.NegativeInfinity:
if upper_limit is S.Infinity:
return Sum(sequence_term, (sym, 0, S.Infinity)).is_convergent() and \
Sum(sequence_term, (sym, S.NegativeInfinity, 0)).is_convergent()
from sympy.simplify.simplify import simplify
sequence_term = simplify(sequence_term.xreplace({sym: -sym}))
lower_limit = -upper_limit
upper_limit = S.Infinity
sym_ = Dummy(sym.name, integer=True, positive=True)
sequence_term = sequence_term.xreplace({sym: sym_})
sym = sym_
interval = Interval(lower_limit, upper_limit)
# Piecewise function handle
if sequence_term.is_Piecewise:
for func, cond in sequence_term.args:
# see if it represents something going to oo
if cond == True or cond.as_set().sup is S.Infinity:
s = Sum(func, (sym, lower_limit, upper_limit))
return s.is_convergent()
return S.true
### -------- Divergence test ----------- ###
try:
lim_val = limit_seq(sequence_term, sym)
if lim_val is not None and lim_val.is_zero is False:
return S.false
except NotImplementedError:
pass
try:
lim_val_abs = limit_seq(abs(sequence_term), sym)
if lim_val_abs is not None and lim_val_abs.is_zero is False:
return S.false
except NotImplementedError:
pass
order = O(sequence_term, (sym, S.Infinity))
### --------- p-series test (1/n**p) ---------- ###
p_series_test = order.expr.match(sym**p)
if p_series_test is not None:
if p_series_test[p] < -1:
return S.true
if p_series_test[p] >= -1:
return S.false
### ------------- comparison test ------------- ###
# 1/(n**p*log(n)**q*log(log(n))**r) comparison
n_log_test = (order.expr.match(1/(sym**p*log(1/sym)**q*log(-log(1/sym))**r)) or
order.expr.match(1/(sym**p*(-log(1/sym))**q*log(-log(1/sym))**r)))
if n_log_test is not None:
if (n_log_test[p] > 1 or
(n_log_test[p] == 1 and n_log_test[q] > 1) or
(n_log_test[p] == n_log_test[q] == 1 and n_log_test[r] > 1)):
return S.true
return S.false
### ------------- Limit comparison test -----------###
# (1/n) comparison
try:
lim_comp = limit_seq(sym*sequence_term, sym)
if lim_comp is not None and lim_comp.is_number and lim_comp > 0:
return S.false
except NotImplementedError:
pass
### ----------- ratio test ---------------- ###
next_sequence_term = sequence_term.xreplace({sym: sym + 1})
from sympy.simplify.combsimp import combsimp
from sympy.simplify.powsimp import powsimp
ratio = combsimp(powsimp(next_sequence_term/sequence_term))
try:
lim_ratio = limit_seq(ratio, sym)
if lim_ratio is not None and lim_ratio.is_number:
if abs(lim_ratio) > 1:
return S.false
if abs(lim_ratio) < 1:
return S.true
except NotImplementedError:
lim_ratio = None
### ---------- Raabe's test -------------- ###
if lim_ratio == 1: # ratio test inconclusive
test_val = sym*(sequence_term/
sequence_term.subs(sym, sym + 1) - 1)
test_val = test_val.gammasimp()
try:
lim_val = limit_seq(test_val, sym)
if lim_val is not None and lim_val.is_number:
if lim_val > 1:
return S.true
if lim_val < 1:
return S.false
except NotImplementedError:
pass
### ----------- root test ---------------- ###
# lim = Limit(abs(sequence_term)**(1/sym), sym, S.Infinity)
try:
lim_evaluated = limit_seq(abs(sequence_term)**(1/sym), sym)
if lim_evaluated is not None and lim_evaluated.is_number:
if lim_evaluated < 1:
return S.true
if lim_evaluated > 1:
return S.false
except NotImplementedError:
pass
### ------------- alternating series test ----------- ###
dict_val = sequence_term.match(S.NegativeOne**(sym + p)*q)
if not dict_val[p].has(sym) and is_decreasing(dict_val[q], interval):
return S.true
### ------------- integral test -------------- ###
check_interval = None
from sympy.solvers.solveset import solveset
maxima = solveset(sequence_term.diff(sym), sym, interval)
if not maxima:
check_interval = interval
elif isinstance(maxima, FiniteSet) and maxima.sup.is_number:
check_interval = Interval(maxima.sup, interval.sup)
if (check_interval is not None and
(is_decreasing(sequence_term, check_interval) or
is_decreasing(-sequence_term, check_interval))):
integral_val = Integral(
sequence_term, (sym, lower_limit, upper_limit))
try:
integral_val_evaluated = integral_val.doit()
if integral_val_evaluated.is_number:
return S(integral_val_evaluated.is_finite)
except NotImplementedError:
pass
### ----- Dirichlet and bounded times convergent tests ----- ###
# TODO
#
# Dirichlet_test
# https://en.wikipedia.org/wiki/Dirichlet%27s_test
#
# Bounded times convergent test
# It is based on comparison theorems for series.
# In particular, if the general term of a series can
# be written as a product of two terms a_n and b_n
# and if a_n is bounded and if Sum(b_n) is absolutely
# convergent, then the original series Sum(a_n * b_n)
# is absolutely convergent and so convergent.
#
# The following code can grows like 2**n where n is the
# number of args in order.expr
# Possibly combined with the potentially slow checks
# inside the loop, could make this test extremely slow
# for larger summation expressions.
if order.expr.is_Mul:
args = order.expr.args
argset = set(args)
### -------------- Dirichlet tests -------------- ###
m = Dummy('m', integer=True)
def _dirichlet_test(g_n):
try:
ing_val = limit_seq(Sum(g_n, (sym, interval.inf, m)).doit(), m)
if ing_val is not None and ing_val.is_finite:
return S.true
except NotImplementedError:
pass
### -------- bounded times convergent test ---------###
def _bounded_convergent_test(g1_n, g2_n):
try:
lim_val = limit_seq(g1_n, sym)
if lim_val is not None and (lim_val.is_finite or (
isinstance(lim_val, AccumulationBounds)
and (lim_val.max - lim_val.min).is_finite)):
if Sum(g2_n, (sym, lower_limit, upper_limit)).is_absolutely_convergent():
return S.true
except NotImplementedError:
pass
for n in range(1, len(argset)):
for a_tuple in itertools.combinations(args, n):
b_set = argset - set(a_tuple)
a_n = Mul(*a_tuple)
b_n = Mul(*b_set)
if is_decreasing(a_n, interval):
dirich = _dirichlet_test(b_n)
if dirich is not None:
return dirich
bc_test = _bounded_convergent_test(a_n, b_n)
if bc_test is not None:
return bc_test
_sym = self.limits[0][0]
sequence_term = sequence_term.xreplace({sym: _sym})
raise NotImplementedError("The algorithm to find the Sum convergence of %s "
"is not yet implemented" % (sequence_term))
def is_absolutely_convergent(self):
"""
Checks for the absolute convergence of an infinite series.
Same as checking convergence of absolute value of sequence_term of
an infinite series.
References
==========
.. [1] https://en.wikipedia.org/wiki/Absolute_convergence
Examples
========
>>> from sympy import Sum, Symbol, oo
>>> n = Symbol('n', integer=True)
>>> Sum((-1)**n, (n, 1, oo)).is_absolutely_convergent()
False
>>> Sum((-1)**n/n**2, (n, 1, oo)).is_absolutely_convergent()
True
See Also
========
Sum.is_convergent
"""
return Sum(abs(self.function), self.limits).is_convergent()
def euler_maclaurin(self, m=0, n=0, eps=0, eval_integral=True):
"""
Return an Euler-Maclaurin approximation of self, where m is the
number of leading terms to sum directly and n is the number of
terms in the tail.
With m = n = 0, this is simply the corresponding integral
plus a first-order endpoint correction.
Returns (s, e) where s is the Euler-Maclaurin approximation
and e is the estimated error (taken to be the magnitude of
the first omitted term in the tail):
>>> from sympy.abc import k, a, b
>>> from sympy import Sum
>>> Sum(1/k, (k, 2, 5)).doit().evalf()
1.28333333333333
>>> s, e = Sum(1/k, (k, 2, 5)).euler_maclaurin()
>>> s
-log(2) + 7/20 + log(5)
>>> from sympy import sstr
>>> print(sstr((s.evalf(), e.evalf()), full_prec=True))
(1.26629073187415, 0.0175000000000000)
The endpoints may be symbolic:
>>> s, e = Sum(1/k, (k, a, b)).euler_maclaurin()
>>> s
-log(a) + log(b) + 1/(2*b) + 1/(2*a)
>>> e
Abs(1/(12*b**2) - 1/(12*a**2))
If the function is a polynomial of degree at most 2n+1, the
Euler-Maclaurin formula becomes exact (and e = 0 is returned):
>>> Sum(k, (k, 2, b)).euler_maclaurin()
(b**2/2 + b/2 - 1, 0)
>>> Sum(k, (k, 2, b)).doit()
b**2/2 + b/2 - 1
With a nonzero eps specified, the summation is ended
as soon as the remainder term is less than the epsilon.
"""
m = int(m)
n = int(n)
f = self.function
if len(self.limits) != 1:
raise ValueError("More than 1 limit")
i, a, b = self.limits[0]
if (a > b) == True:
if a - b == 1:
return S.Zero, S.Zero
a, b = b + 1, a - 1
f = -f
s = S.Zero
if m:
if b.is_Integer and a.is_Integer:
m = min(m, b - a + 1)
if not eps or f.is_polynomial(i):
s = Add(*[f.subs(i, a + k) for k in range(m)])
else:
term = f.subs(i, a)
if term:
test = abs(term.evalf(3)) < eps
if test == True:
return s, abs(term)
elif not (test == False):
# a symbolic Relational class, can't go further
return term, S.Zero
s = term
for k in range(1, m):
term = f.subs(i, a + k)
if abs(term.evalf(3)) < eps and term != 0:
return s, abs(term)
s += term
if b - a + 1 == m:
return s, S.Zero
a += m
x = Dummy('x')
I = Integral(f.subs(i, x), (x, a, b))
if eval_integral:
I = I.doit()
s += I
def fpoint(expr):
if b is S.Infinity:
return expr.subs(i, a), 0
return expr.subs(i, a), expr.subs(i, b)
fa, fb = fpoint(f)
iterm = (fa + fb)/2
g = f.diff(i)
for k in range(1, n + 2):
ga, gb = fpoint(g)
term = bernoulli(2*k)/factorial(2*k)*(gb - ga)
if k > n:
break
if eps and term:
term_evalf = term.evalf(3)
if term_evalf is S.NaN:
return S.NaN, S.NaN
if abs(term_evalf) < eps:
break
s += term
g = g.diff(i, 2, simplify=False)
return s + iterm, abs(term)
def reverse_order(self, *indices):
"""
Reverse the order of a limit in a Sum.
Explanation
===========
``reverse_order(self, *indices)`` reverses some limits in the expression
``self`` which can be either a ``Sum`` or a ``Product``. The selectors in
the argument ``indices`` specify some indices whose limits get reversed.
These selectors are either variable names or numerical indices counted
starting from the inner-most limit tuple.
Examples
========
>>> from sympy import Sum
>>> from sympy.abc import x, y, a, b, c, d
>>> Sum(x, (x, 0, 3)).reverse_order(x)
Sum(-x, (x, 4, -1))
>>> Sum(x*y, (x, 1, 5), (y, 0, 6)).reverse_order(x, y)
Sum(x*y, (x, 6, 0), (y, 7, -1))
>>> Sum(x, (x, a, b)).reverse_order(x)
Sum(-x, (x, b + 1, a - 1))
>>> Sum(x, (x, a, b)).reverse_order(0)
Sum(-x, (x, b + 1, a - 1))
While one should prefer variable names when specifying which limits
to reverse, the index counting notation comes in handy in case there
are several symbols with the same name.
>>> S = Sum(x**2, (x, a, b), (x, c, d))
>>> S
Sum(x**2, (x, a, b), (x, c, d))
>>> S0 = S.reverse_order(0)
>>> S0
Sum(-x**2, (x, b + 1, a - 1), (x, c, d))
>>> S1 = S0.reverse_order(1)
>>> S1
Sum(x**2, (x, b + 1, a - 1), (x, d + 1, c - 1))
Of course we can mix both notations:
>>> Sum(x*y, (x, a, b), (y, 2, 5)).reverse_order(x, 1)
Sum(x*y, (x, b + 1, a - 1), (y, 6, 1))
>>> Sum(x*y, (x, a, b), (y, 2, 5)).reverse_order(y, x)
Sum(x*y, (x, b + 1, a - 1), (y, 6, 1))
See Also
========
sympy.concrete.expr_with_intlimits.ExprWithIntLimits.index, reorder_limit,
sympy.concrete.expr_with_intlimits.ExprWithIntLimits.reorder
References
==========
.. [1] Michael Karr, "Summation in Finite Terms", Journal of the ACM,
Volume 28 Issue 2, April 1981, Pages 305-350
https://dl.acm.org/doi/10.1145/322248.322255
"""
l_indices = list(indices)
for i, indx in enumerate(l_indices):
if not isinstance(indx, int):
l_indices[i] = self.index(indx)
e = 1
limits = []
for i, limit in enumerate(self.limits):
l = limit
if i in l_indices:
e = -e
l = (limit[0], limit[2] + 1, limit[1] - 1)
limits.append(l)
return Sum(e * self.function, *limits)
def _eval_rewrite_as_Product(self, *args, **kwargs):
from sympy.concrete.products import Product
if self.function.is_extended_real:
return log(Product(exp(self.function), *self.limits))
def summation(f, *symbols, **kwargs):
r"""
Compute the summation of f with respect to symbols.
Explanation
===========
The notation for symbols is similar to the notation used in Integral.
summation(f, (i, a, b)) computes the sum of f with respect to i from a to b,
i.e.,
::
b
____
\ `
summation(f, (i, a, b)) = ) f
/___,
i = a
If it cannot compute the sum, it returns an unevaluated Sum object.
Repeated sums can be computed by introducing additional symbols tuples::
Examples
========
>>> from sympy import summation, oo, symbols, log
>>> i, n, m = symbols('i n m', integer=True)
>>> summation(2*i - 1, (i, 1, n))
n**2
>>> summation(1/2**i, (i, 0, oo))
2
>>> summation(1/log(n)**n, (n, 2, oo))
Sum(log(n)**(-n), (n, 2, oo))
>>> summation(i, (i, 0, n), (n, 0, m))
m**3/6 + m**2/2 + m/3
>>> from sympy.abc import x
>>> from sympy import factorial
>>> summation(x**n/factorial(n), (n, 0, oo))
exp(x)
See Also
========
Sum
Product, sympy.concrete.products.product
"""
return Sum(f, *symbols, **kwargs).doit(deep=False)
def telescopic_direct(L, R, n, limits):
"""
Returns the direct summation of the terms of a telescopic sum
Explanation
===========
L is the term with lower index
R is the term with higher index
n difference between the indexes of L and R
Examples
========
>>> from sympy.concrete.summations import telescopic_direct
>>> from sympy.abc import k, a, b
>>> telescopic_direct(1/k, -1/(k+2), 2, (k, a, b))
-1/(b + 2) - 1/(b + 1) + 1/(a + 1) + 1/a
"""
(i, a, b) = limits
return Add(*[L.subs(i, a + m) + R.subs(i, b - m) for m in range(n)])
def telescopic(L, R, limits):
'''
Tries to perform the summation using the telescopic property.
Return None if not possible.
'''
(i, a, b) = limits
if L.is_Add or R.is_Add:
return None
# We want to solve(L.subs(i, i + m) + R, m)
# First we try a simple match since this does things that
# solve doesn't do, e.g. solve(cos(k+m)-cos(k), m) gives
# a more complicated solution than m == 0.
k = Wild("k")
sol = (-R).match(L.subs(i, i + k))
s = None
if sol and k in sol:
s = sol[k]
if not (s.is_Integer and L.subs(i, i + s) + R == 0):
# invalid match or match didn't work
s = None
# But there are things that match doesn't do that solve
# can do, e.g. determine that 1/(x + m) = 1/(1 - x) when m = 1
if s is None:
m = Dummy('m')
try:
from sympy.solvers.solvers import solve
sol = solve(L.subs(i, i + m) + R, m) or []
except NotImplementedError:
return None
sol = [si for si in sol if si.is_Integer and
(L.subs(i, i + si) + R).expand().is_zero]
if len(sol) != 1:
return None
s = sol[0]
if s < 0:
return telescopic_direct(R, L, abs(s), (i, a, b))
elif s > 0:
return telescopic_direct(L, R, s, (i, a, b))
def eval_sum(f, limits):
(i, a, b) = limits
if f.is_zero:
return S.Zero
if i not in f.free_symbols:
return f*(b - a + 1)
if a == b:
return f.subs(i, a)
if isinstance(f, Piecewise):
if not any(i in arg.args[1].free_symbols for arg in f.args):
# Piecewise conditions do not depend on the dummy summation variable,
# therefore we can fold: Sum(Piecewise((e, c), ...), limits)
# --> Piecewise((Sum(e, limits), c), ...)
newargs = []
for arg in f.args:
newexpr = eval_sum(arg.expr, limits)
if newexpr is None:
return None
newargs.append((newexpr, arg.cond))
return f.func(*newargs)
if f.has(KroneckerDelta):
from .delta import deltasummation, _has_simple_delta
f = f.replace(
lambda x: isinstance(x, Sum),
lambda x: x.factor()
)
if _has_simple_delta(f, limits[0]):
return deltasummation(f, limits)
dif = b - a
definite = dif.is_Integer
# Doing it directly may be faster if there are very few terms.
if definite and (dif < 100):
return eval_sum_direct(f, (i, a, b))
if isinstance(f, Piecewise):
return None
# Try to do it symbolically. Even when the number of terms is
# known, this can save time when b-a is big.
value = eval_sum_symbolic(f.expand(), (i, a, b))
if value is not None:
return value
# Do it directly
if definite:
return eval_sum_direct(f, (i, a, b))
def eval_sum_direct(expr, limits):
"""
Evaluate expression directly, but perform some simple checks first
to possibly result in a smaller expression and faster execution.
"""
(i, a, b) = limits
dif = b - a
# Linearity
if expr.is_Mul:
# Try factor out everything not including i
without_i, with_i = expr.as_independent(i)
if without_i != 1:
s = eval_sum_direct(with_i, (i, a, b))
if s:
r = without_i*s
if r is not S.NaN:
return r
else:
# Try term by term
L, R = expr.as_two_terms()
if not L.has(i):
sR = eval_sum_direct(R, (i, a, b))
if sR:
return L*sR
if not R.has(i):
sL = eval_sum_direct(L, (i, a, b))
if sL:
return sL*R
# do this whether its an Add or Mul
# e.g. apart(1/(25*i**2 + 45*i + 14)) and
# apart(1/((5*i + 2)*(5*i + 7))) ->
# -1/(5*(5*i + 7)) + 1/(5*(5*i + 2))
try:
expr = apart(expr, i) # see if it becomes an Add
except PolynomialError:
pass
if expr.is_Add:
# Try factor out everything not including i
without_i, with_i = expr.as_independent(i)
if without_i != 0:
s = eval_sum_direct(with_i, (i, a, b))
if s:
r = without_i*(dif + 1) + s
if r is not S.NaN:
return r
else:
# Try term by term
L, R = expr.as_two_terms()
lsum = eval_sum_direct(L, (i, a, b))
rsum = eval_sum_direct(R, (i, a, b))
if None not in (lsum, rsum):
r = lsum + rsum
if r is not S.NaN:
return r
return Add(*[expr.subs(i, a + j) for j in range(dif + 1)])
def eval_sum_symbolic(f, limits):
f_orig = f
(i, a, b) = limits
if not f.has(i):
return f*(b - a + 1)
# Linearity
if f.is_Mul:
# Try factor out everything not including i
without_i, with_i = f.as_independent(i)
if without_i != 1:
s = eval_sum_symbolic(with_i, (i, a, b))
if s:
r = without_i*s
if r is not S.NaN:
return r
else:
# Try term by term
L, R = f.as_two_terms()
if not L.has(i):
sR = eval_sum_symbolic(R, (i, a, b))
if sR:
return L*sR
if not R.has(i):
sL = eval_sum_symbolic(L, (i, a, b))
if sL:
return sL*R
# do this whether its an Add or Mul
# e.g. apart(1/(25*i**2 + 45*i + 14)) and
# apart(1/((5*i + 2)*(5*i + 7))) ->
# -1/(5*(5*i + 7)) + 1/(5*(5*i + 2))
try:
f = apart(f, i)
except PolynomialError:
pass
if f.is_Add:
L, R = f.as_two_terms()
lrsum = telescopic(L, R, (i, a, b))
if lrsum:
return lrsum
# Try factor out everything not including i
without_i, with_i = f.as_independent(i)
if without_i != 0:
s = eval_sum_symbolic(with_i, (i, a, b))
if s:
r = without_i*(b - a + 1) + s
if r is not S.NaN:
return r
else:
# Try term by term
lsum = eval_sum_symbolic(L, (i, a, b))
rsum = eval_sum_symbolic(R, (i, a, b))
if None not in (lsum, rsum):
r = lsum + rsum
if r is not S.NaN:
return r
# Polynomial terms with Faulhaber's formula
n = Wild('n')
result = f.match(i**n)
if result is not None:
n = result[n]
if n.is_Integer:
if n >= 0:
if (b is S.Infinity and a is not S.NegativeInfinity) or \
(a is S.NegativeInfinity and b is not S.Infinity):
return S.Infinity
return ((bernoulli(n + 1, b + 1) - bernoulli(n + 1, a))/(n + 1)).expand()
elif a.is_Integer and a >= 1:
if n == -1:
return harmonic(b) - harmonic(a - 1)
else:
return harmonic(b, abs(n)) - harmonic(a - 1, abs(n))
if not (a.has(S.Infinity, S.NegativeInfinity) or
b.has(S.Infinity, S.NegativeInfinity)):
# Geometric terms
c1 = Wild('c1', exclude=[i])
c2 = Wild('c2', exclude=[i])
c3 = Wild('c3', exclude=[i])
wexp = Wild('wexp')
# Here we first attempt powsimp on f for easier matching with the
# exponential pattern, and attempt expansion on the exponent for easier
# matching with the linear pattern.
e = f.powsimp().match(c1 ** wexp)
if e is not None:
e_exp = e.pop(wexp).expand().match(c2*i + c3)
if e_exp is not None:
e.update(e_exp)
p = (c1**c3).subs(e)
q = (c1**c2).subs(e)
r = p*(q**a - q**(b + 1))/(1 - q)
l = p*(b - a + 1)
return Piecewise((l, Eq(q, S.One)), (r, True))
r = gosper_sum(f, (i, a, b))
if isinstance(r, (Mul,Add)):
from sympy.simplify.radsimp import denom
from sympy.solvers.solvers import solve
non_limit = r.free_symbols - Tuple(*limits[1:]).free_symbols
den = denom(together(r))
den_sym = non_limit & den.free_symbols
args = []
for v in ordered(den_sym):
try:
s = solve(den, v)
m = Eq(v, s[0]) if s else S.false
if m != False:
args.append((Sum(f_orig.subs(*m.args), limits).doit(), m))
break
except NotImplementedError:
continue
args.append((r, True))
return Piecewise(*args)
if r not in (None, S.NaN):
return r
h = eval_sum_hyper(f_orig, (i, a, b))
if h is not None:
return h
r = eval_sum_residue(f_orig, (i, a, b))
if r is not None:
return r
factored = f_orig.factor()
if factored != f_orig:
return eval_sum_symbolic(factored, (i, a, b))
def _eval_sum_hyper(f, i, a):
""" Returns (res, cond). Sums from a to oo. """
if a != 0:
return _eval_sum_hyper(f.subs(i, i + a), i, 0)
if f.subs(i, 0) == 0:
from sympy.simplify.simplify import simplify
if simplify(f.subs(i, Dummy('i', integer=True, positive=True))) == 0:
return S.Zero, True
return _eval_sum_hyper(f.subs(i, i + 1), i, 0)
from sympy.simplify.simplify import hypersimp
hs = hypersimp(f, i)
if hs is None:
return None
if isinstance(hs, Float):
from sympy.simplify.simplify import nsimplify
hs = nsimplify(hs)
from sympy.simplify.combsimp import combsimp
from sympy.simplify.hyperexpand import hyperexpand
from sympy.simplify.radsimp import fraction
numer, denom = fraction(factor(hs))
top, topl = numer.as_coeff_mul(i)
bot, botl = denom.as_coeff_mul(i)
ab = [top, bot]
factors = [topl, botl]
params = [[], []]
for k in range(2):
for fac in factors[k]:
mul = 1
if fac.is_Pow:
mul = fac.exp
fac = fac.base
if not mul.is_Integer:
return None
p = Poly(fac, i)
if p.degree() != 1:
return None
m, n = p.all_coeffs()
ab[k] *= m**mul
params[k] += [n/m]*mul
# Add "1" to numerator parameters, to account for implicit n! in
# hypergeometric series.
ap = params[0] + [1]
bq = params[1]
x = ab[0]/ab[1]
h = hyper(ap, bq, x)
f = combsimp(f)
return f.subs(i, 0)*hyperexpand(h), h.convergence_statement
def eval_sum_hyper(f, i_a_b):
i, a, b = i_a_b
if f.is_hypergeometric(i) is False:
return
if (b - a).is_Integer:
# We are never going to do better than doing the sum in the obvious way
return None
old_sum = Sum(f, (i, a, b))
if b != S.Infinity:
if a is S.NegativeInfinity:
res = _eval_sum_hyper(f.subs(i, -i), i, -b)
if res is not None:
return Piecewise(res, (old_sum, True))
else:
n_illegal = lambda x: sum(x.count(_) for _ in _illegal)
had = n_illegal(f)
# check that no extra illegals are introduced
res1 = _eval_sum_hyper(f, i, a)
if res1 is None or n_illegal(res1) > had:
return
res2 = _eval_sum_hyper(f, i, b + 1)
if res2 is None or n_illegal(res2) > had:
return
(res1, cond1), (res2, cond2) = res1, res2
cond = And(cond1, cond2)
if cond == False:
return None
return Piecewise((res1 - res2, cond), (old_sum, True))
if a is S.NegativeInfinity:
res1 = _eval_sum_hyper(f.subs(i, -i), i, 1)
res2 = _eval_sum_hyper(f, i, 0)
if res1 is None or res2 is None:
return None
res1, cond1 = res1
res2, cond2 = res2
cond = And(cond1, cond2)
if cond == False or cond.as_set() == S.EmptySet:
return None
return Piecewise((res1 + res2, cond), (old_sum, True))
# Now b == oo, a != -oo
res = _eval_sum_hyper(f, i, a)
if res is not None:
r, c = res
if c == False:
if r.is_number:
f = f.subs(i, Dummy('i', integer=True, positive=True) + a)
if f.is_positive or f.is_zero:
return S.Infinity
elif f.is_negative:
return S.NegativeInfinity
return None
return Piecewise(res, (old_sum, True))
def eval_sum_residue(f, i_a_b):
r"""Compute the infinite summation with residues
Notes
=====
If $f(n), g(n)$ are polynomials with $\deg(g(n)) - \deg(f(n)) \ge 2$,
some infinite summations can be computed by the following residue
evaluations.
.. math::
\sum_{n=-\infty, g(n) \ne 0}^{\infty} \frac{f(n)}{g(n)} =
-\pi \sum_{\alpha|g(\alpha)=0}
\text{Res}(\cot(\pi x) \frac{f(x)}{g(x)}, \alpha)
.. math::
\sum_{n=-\infty, g(n) \ne 0}^{\infty} (-1)^n \frac{f(n)}{g(n)} =
-\pi \sum_{\alpha|g(\alpha)=0}
\text{Res}(\csc(\pi x) \frac{f(x)}{g(x)}, \alpha)
Examples
========
>>> from sympy import Sum, oo, Symbol
>>> x = Symbol('x')
Doubly infinite series of rational functions.
>>> Sum(1 / (x**2 + 1), (x, -oo, oo)).doit()
pi/tanh(pi)
Doubly infinite alternating series of rational functions.
>>> Sum((-1)**x / (x**2 + 1), (x, -oo, oo)).doit()
pi/sinh(pi)
Infinite series of even rational functions.
>>> Sum(1 / (x**2 + 1), (x, 0, oo)).doit()
1/2 + pi/(2*tanh(pi))
Infinite series of alternating even rational functions.
>>> Sum((-1)**x / (x**2 + 1), (x, 0, oo)).doit()
pi/(2*sinh(pi)) + 1/2
This also have heuristics to transform arbitrarily shifted summand or
arbitrarily shifted summation range to the canonical problem the
formula can handle.
>>> Sum(1 / (x**2 + 2*x + 2), (x, -1, oo)).doit()
1/2 + pi/(2*tanh(pi))
>>> Sum(1 / (x**2 + 4*x + 5), (x, -2, oo)).doit()
1/2 + pi/(2*tanh(pi))
>>> Sum(1 / (x**2 + 1), (x, 1, oo)).doit()
-1/2 + pi/(2*tanh(pi))
>>> Sum(1 / (x**2 + 1), (x, 2, oo)).doit()
-1 + pi/(2*tanh(pi))
References
==========
.. [#] http://www.supermath.info/InfiniteSeriesandtheResidueTheorem.pdf
.. [#] Asmar N.H., Grafakos L. (2018) Residue Theory.
In: Complex Analysis with Applications.
Undergraduate Texts in Mathematics. Springer, Cham.
https://doi.org/10.1007/978-3-319-94063-2_5
"""
i, a, b = i_a_b
def is_even_function(numer, denom):
"""Test if the rational function is an even function"""
numer_even = all(i % 2 == 0 for (i,) in numer.monoms())
denom_even = all(i % 2 == 0 for (i,) in denom.monoms())
numer_odd = all(i % 2 == 1 for (i,) in numer.monoms())
denom_odd = all(i % 2 == 1 for (i,) in denom.monoms())
return (numer_even and denom_even) or (numer_odd and denom_odd)
def match_rational(f, i):
numer, denom = f.as_numer_denom()
try:
(numer, denom), opt = parallel_poly_from_expr((numer, denom), i)
except (PolificationFailed, PolynomialError):
return None
return numer, denom
def get_poles(denom):
roots = denom.sqf_part().all_roots()
roots = sift(roots, lambda x: x.is_integer)
if None in roots:
return None
int_roots, nonint_roots = roots[True], roots[False]
return int_roots, nonint_roots
def get_shift(denom):
n = denom.degree(i)
a = denom.coeff_monomial(i**n)
b = denom.coeff_monomial(i**(n-1))
shift = - b / a / n
return shift
#Need a dummy symbol with no assumptions set for get_residue_factor
z = Dummy('z')
def get_residue_factor(numer, denom, alternating):
residue_factor = (numer.as_expr() / denom.as_expr()).subs(i, z)
if not alternating:
residue_factor *= cot(S.Pi * z)
else:
residue_factor *= csc(S.Pi * z)
return residue_factor
# We don't know how to deal with symbolic constants in summand
if f.free_symbols - {i}:
return None
if not (a.is_Integer or a in (S.Infinity, S.NegativeInfinity)):
return None
if not (b.is_Integer or b in (S.Infinity, S.NegativeInfinity)):
return None
# Quick exit heuristic for the sums which doesn't have infinite range
if a != S.NegativeInfinity and b != S.Infinity:
return None
match = match_rational(f, i)
if match:
alternating = False
numer, denom = match
else:
match = match_rational(f / S.NegativeOne**i, i)
if match:
alternating = True
numer, denom = match
else:
return None
if denom.degree(i) - numer.degree(i) < 2:
return None
if (a, b) == (S.NegativeInfinity, S.Infinity):
poles = get_poles(denom)
if poles is None:
return None
int_roots, nonint_roots = poles
if int_roots:
return None
residue_factor = get_residue_factor(numer, denom, alternating)
residues = [residue(residue_factor, z, root) for root in nonint_roots]
return -S.Pi * sum(residues)
if not (a.is_finite and b is S.Infinity):
return None
if not is_even_function(numer, denom):
# Try shifting summation and check if the summand can be made
# and even function from the origin.
# Sum(f(n), (n, a, b)) => Sum(f(n + s), (n, a - s, b - s))
shift = get_shift(denom)
if not shift.is_Integer:
return None
if shift == 0:
return None
numer = numer.shift(shift)
denom = denom.shift(shift)
if not is_even_function(numer, denom):
return None
if alternating:
f = S.NegativeOne**i * (S.NegativeOne**shift * numer.as_expr() / denom.as_expr())
else:
f = numer.as_expr() / denom.as_expr()
return eval_sum_residue(f, (i, a-shift, b-shift))
poles = get_poles(denom)
if poles is None:
return None
int_roots, nonint_roots = poles
if int_roots:
int_roots = [int(root) for root in int_roots]
int_roots_max = max(int_roots)
int_roots_min = min(int_roots)
# Integer valued poles must be next to each other
# and also symmetric from origin (Because the function is even)
if not len(int_roots) == int_roots_max - int_roots_min + 1:
return None
# Check whether the summation indices contain poles
if a <= max(int_roots):
return None
residue_factor = get_residue_factor(numer, denom, alternating)
residues = [residue(residue_factor, z, root) for root in int_roots + nonint_roots]
full_sum = -S.Pi * sum(residues)
if not int_roots:
# Compute Sum(f, (i, 0, oo)) by adding a extraneous evaluation
# at the origin.
half_sum = (full_sum + f.xreplace({i: 0})) / 2
# Add and subtract extraneous evaluations
extraneous_neg = [f.xreplace({i: i0}) for i0 in range(int(a), 0)]
extraneous_pos = [f.xreplace({i: i0}) for i0 in range(0, int(a))]
result = half_sum + sum(extraneous_neg) - sum(extraneous_pos)
return result
# Compute Sum(f, (i, min(poles) + 1, oo))
half_sum = full_sum / 2
# Subtract extraneous evaluations
extraneous = [f.xreplace({i: i0}) for i0 in range(max(int_roots) + 1, int(a))]
result = half_sum - sum(extraneous)
return result
def _eval_matrix_sum(expression):
f = expression.function
for limit in expression.limits:
i, a, b = limit
dif = b - a
if dif.is_Integer:
if (dif < 0) == True:
a, b = b + 1, a - 1
f = -f
newf = eval_sum_direct(f, (i, a, b))
if newf is not None:
return newf.doit()
def _dummy_with_inherited_properties_concrete(limits):
"""
Return a Dummy symbol that inherits as many assumptions as possible
from the provided symbol and limits.
If the symbol already has all True assumption shared by the limits
then return None.
"""
x, a, b = limits
l = [a, b]
assumptions_to_consider = ['extended_nonnegative', 'nonnegative',
'extended_nonpositive', 'nonpositive',
'extended_positive', 'positive',
'extended_negative', 'negative',
'integer', 'rational', 'finite',
'zero', 'real', 'extended_real']
assumptions_to_keep = {}
assumptions_to_add = {}
for assum in assumptions_to_consider:
assum_true = x._assumptions.get(assum, None)
if assum_true:
assumptions_to_keep[assum] = True
elif all(getattr(i, 'is_' + assum) for i in l):
assumptions_to_add[assum] = True
if assumptions_to_add:
assumptions_to_keep.update(assumptions_to_add)
return Dummy('d', **assumptions_to_keep)
PK ]ZZZ��#�3 3 sympy/core/__init__.py"""Core module. Provides the basic operations needed in sympy.
"""
from .sympify import sympify, SympifyError
from .cache import cacheit
from .assumptions import assumptions, check_assumptions, failing_assumptions, common_assumptions
from .basic import Basic, Atom
from .singleton import S
from .expr import Expr, AtomicExpr, UnevaluatedExpr
from .symbol import Symbol, Wild, Dummy, symbols, var
from .numbers import Number, Float, Rational, Integer, NumberSymbol, \
RealNumber, igcd, ilcm, seterr, E, I, nan, oo, pi, zoo, \
AlgebraicNumber, comp, mod_inverse
from .power import Pow
from .intfunc import integer_nthroot, integer_log, num_digits, trailing
from .mul import Mul, prod
from .add import Add
from .mod import Mod
from .relational import ( Rel, Eq, Ne, Lt, Le, Gt, Ge,
Equality, GreaterThan, LessThan, Unequality, StrictGreaterThan,
StrictLessThan )
from .multidimensional import vectorize
from .function import Lambda, WildFunction, Derivative, diff, FunctionClass, \
Function, Subs, expand, PoleError, count_ops, \
expand_mul, expand_log, expand_func, \
expand_trig, expand_complex, expand_multinomial, nfloat, \
expand_power_base, expand_power_exp, arity
from .evalf import PrecisionExhausted, N
from .containers import Tuple, Dict
from .exprtools import gcd_terms, factor_terms, factor_nc
from .parameters import evaluate
from .kind import UndefinedKind, NumberKind, BooleanKind
from .traversal import preorder_traversal, bottom_up, use, postorder_traversal
from .sorting import default_sort_key, ordered
# expose singletons
Catalan = S.Catalan
EulerGamma = S.EulerGamma
GoldenRatio = S.GoldenRatio
TribonacciConstant = S.TribonacciConstant
__all__ = [
'sympify', 'SympifyError',
'cacheit',
'assumptions', 'check_assumptions', 'failing_assumptions',
'common_assumptions',
'Basic', 'Atom',
'S',
'Expr', 'AtomicExpr', 'UnevaluatedExpr',
'Symbol', 'Wild', 'Dummy', 'symbols', 'var',
'Number', 'Float', 'Rational', 'Integer', 'NumberSymbol', 'RealNumber',
'igcd', 'ilcm', 'seterr', 'E', 'I', 'nan', 'oo', 'pi', 'zoo',
'AlgebraicNumber', 'comp', 'mod_inverse',
'Pow',
'integer_nthroot', 'integer_log', 'num_digits', 'trailing',
'Mul', 'prod',
'Add',
'Mod',
'Rel', 'Eq', 'Ne', 'Lt', 'Le', 'Gt', 'Ge', 'Equality', 'GreaterThan',
'LessThan', 'Unequality', 'StrictGreaterThan', 'StrictLessThan',
'vectorize',
'Lambda', 'WildFunction', 'Derivative', 'diff', 'FunctionClass',
'Function', 'Subs', 'expand', 'PoleError', 'count_ops', 'expand_mul',
'expand_log', 'expand_func', 'expand_trig', 'expand_complex',
'expand_multinomial', 'nfloat', 'expand_power_base', 'expand_power_exp',
'arity',
'PrecisionExhausted', 'N',
'evalf', # The module?
'Tuple', 'Dict',
'gcd_terms', 'factor_terms', 'factor_nc',
'evaluate',
'Catalan',
'EulerGamma',
'GoldenRatio',
'TribonacciConstant',
'UndefinedKind', 'NumberKind', 'BooleanKind',
'preorder_traversal', 'bottom_up', 'use', 'postorder_traversal',
'default_sort_key', 'ordered',
]
PK ]ZZZ�.\(T T sympy/core/_print_helpers.py"""
Base class to provide str and repr hooks that `init_printing` can overwrite.
This is exposed publicly in the `printing.defaults` module,
but cannot be defined there without causing circular imports.
"""
class Printable:
"""
The default implementation of printing for SymPy classes.
This implements a hack that allows us to print elements of built-in
Python containers in a readable way. Natively Python uses ``repr()``
even if ``str()`` was explicitly requested. Mix in this trait into
a class to get proper default printing.
This also adds support for LaTeX printing in jupyter notebooks.
"""
# Since this class is used as a mixin we set empty slots. That means that
# instances of any subclasses that use slots will not need to have a
# __dict__.
__slots__ = ()
# Note, we always use the default ordering (lex) in __str__ and __repr__,
# regardless of the global setting. See issue 5487.
def __str__(self):
from sympy.printing.str import sstr
return sstr(self, order=None)
__repr__ = __str__
def _repr_disabled(self):
"""
No-op repr function used to disable jupyter display hooks.
When :func:`sympy.init_printing` is used to disable certain display
formats, this function is copied into the appropriate ``_repr_*_``
attributes.
While we could just set the attributes to `None``, doing it this way
allows derived classes to call `super()`.
"""
return None
# We don't implement _repr_png_ here because it would add a large amount of
# data to any notebook containing SymPy expressions, without adding
# anything useful to the notebook. It can still enabled manually, e.g.,
# for the qtconsole, with init_printing().
_repr_png_ = _repr_disabled
_repr_svg_ = _repr_disabled
def _repr_latex_(self):
"""
IPython/Jupyter LaTeX printing
To change the behavior of this (e.g., pass in some settings to LaTeX),
use init_printing(). init_printing() will also enable LaTeX printing
for built in numeric types like ints and container types that contain
SymPy objects, like lists and dictionaries of expressions.
"""
from sympy.printing.latex import latex
s = latex(self, mode='plain')
return "$\\displaystyle %s$" % s
PK ]ZZZ�� �� sympy/core/add.pyfrom typing import Tuple as tTuple
from collections import defaultdict
from functools import reduce
from operator import attrgetter
from .basic import _args_sortkey
from .parameters import global_parameters
from .logic import _fuzzy_group, fuzzy_or, fuzzy_not
from .singleton import S
from .operations import AssocOp, AssocOpDispatcher
from .cache import cacheit
from .numbers import equal_valued
from .intfunc import ilcm, igcd
from .expr import Expr
from .kind import UndefinedKind
from sympy.utilities.iterables import is_sequence, sift
def _could_extract_minus_sign(expr):
# assume expr is Add-like
# We choose the one with less arguments with minus signs
negative_args = sum(1 for i in expr.args
if i.could_extract_minus_sign())
positive_args = len(expr.args) - negative_args
if positive_args > negative_args:
return False
elif positive_args < negative_args:
return True
# choose based on .sort_key() to prefer
# x - 1 instead of 1 - x and
# 3 - sqrt(2) instead of -3 + sqrt(2)
return bool(expr.sort_key() < (-expr).sort_key())
def _addsort(args):
# in-place sorting of args
args.sort(key=_args_sortkey)
def _unevaluated_Add(*args):
"""Return a well-formed unevaluated Add: Numbers are collected and
put in slot 0 and args are sorted. Use this when args have changed
but you still want to return an unevaluated Add.
Examples
========
>>> from sympy.core.add import _unevaluated_Add as uAdd
>>> from sympy import S, Add
>>> from sympy.abc import x, y
>>> a = uAdd(*[S(1.0), x, S(2)])
>>> a.args[0]
3.00000000000000
>>> a.args[1]
x
Beyond the Number being in slot 0, there is no other assurance of
order for the arguments since they are hash sorted. So, for testing
purposes, output produced by this in some other function can only
be tested against the output of this function or as one of several
options:
>>> opts = (Add(x, y, evaluate=False), Add(y, x, evaluate=False))
>>> a = uAdd(x, y)
>>> assert a in opts and a == uAdd(x, y)
>>> uAdd(x + 1, x + 2)
x + x + 3
"""
args = list(args)
newargs = []
co = S.Zero
while args:
a = args.pop()
if a.is_Add:
# this will keep nesting from building up
# so that x + (x + 1) -> x + x + 1 (3 args)
args.extend(a.args)
elif a.is_Number:
co += a
else:
newargs.append(a)
_addsort(newargs)
if co:
newargs.insert(0, co)
return Add._from_args(newargs)
class Add(Expr, AssocOp):
"""
Expression representing addition operation for algebraic group.
.. deprecated:: 1.7
Using arguments that aren't subclasses of :class:`~.Expr` in core
operators (:class:`~.Mul`, :class:`~.Add`, and :class:`~.Pow`) is
deprecated. See :ref:`non-expr-args-deprecated` for details.
Every argument of ``Add()`` must be ``Expr``. Infix operator ``+``
on most scalar objects in SymPy calls this class.
Another use of ``Add()`` is to represent the structure of abstract
addition so that its arguments can be substituted to return different
class. Refer to examples section for this.
``Add()`` evaluates the argument unless ``evaluate=False`` is passed.
The evaluation logic includes:
1. Flattening
``Add(x, Add(y, z))`` -> ``Add(x, y, z)``
2. Identity removing
``Add(x, 0, y)`` -> ``Add(x, y)``
3. Coefficient collecting by ``.as_coeff_Mul()``
``Add(x, 2*x)`` -> ``Mul(3, x)``
4. Term sorting
``Add(y, x, 2)`` -> ``Add(2, x, y)``
If no argument is passed, identity element 0 is returned. If single
element is passed, that element is returned.
Note that ``Add(*args)`` is more efficient than ``sum(args)`` because
it flattens the arguments. ``sum(a, b, c, ...)`` recursively adds the
arguments as ``a + (b + (c + ...))``, which has quadratic complexity.
On the other hand, ``Add(a, b, c, d)`` does not assume nested
structure, making the complexity linear.
Since addition is group operation, every argument should have the
same :obj:`sympy.core.kind.Kind()`.
Examples
========
>>> from sympy import Add, I
>>> from sympy.abc import x, y
>>> Add(x, 1)
x + 1
>>> Add(x, x)
2*x
>>> 2*x**2 + 3*x + I*y + 2*y + 2*x/5 + 1.0*y + 1
2*x**2 + 17*x/5 + 3.0*y + I*y + 1
If ``evaluate=False`` is passed, result is not evaluated.
>>> Add(1, 2, evaluate=False)
1 + 2
>>> Add(x, x, evaluate=False)
x + x
``Add()`` also represents the general structure of addition operation.
>>> from sympy import MatrixSymbol
>>> A,B = MatrixSymbol('A', 2,2), MatrixSymbol('B', 2,2)
>>> expr = Add(x,y).subs({x:A, y:B})
>>> expr
A + B
>>> type(expr)
<class 'sympy.matrices.expressions.matadd.MatAdd'>
Note that the printers do not display in args order.
>>> Add(x, 1)
x + 1
>>> Add(x, 1).args
(1, x)
See Also
========
MatAdd
"""
__slots__ = ()
args: tTuple[Expr, ...]
is_Add = True
_args_type = Expr
@classmethod
def flatten(cls, seq):
"""
Takes the sequence "seq" of nested Adds and returns a flatten list.
Returns: (commutative_part, noncommutative_part, order_symbols)
Applies associativity, all terms are commutable with respect to
addition.
NB: the removal of 0 is already handled by AssocOp.__new__
See Also
========
sympy.core.mul.Mul.flatten
"""
from sympy.calculus.accumulationbounds import AccumBounds
from sympy.matrices.expressions import MatrixExpr
from sympy.tensor.tensor import TensExpr
rv = None
if len(seq) == 2:
a, b = seq
if b.is_Rational:
a, b = b, a
if a.is_Rational:
if b.is_Mul:
rv = [a, b], [], None
if rv:
if all(s.is_commutative for s in rv[0]):
return rv
return [], rv[0], None
terms = {} # term -> coeff
# e.g. x**2 -> 5 for ... + 5*x**2 + ...
coeff = S.Zero # coefficient (Number or zoo) to always be in slot 0
# e.g. 3 + ...
order_factors = []
extra = []
for o in seq:
# O(x)
if o.is_Order:
if o.expr.is_zero:
continue
for o1 in order_factors:
if o1.contains(o):
o = None
break
if o is None:
continue
order_factors = [o] + [
o1 for o1 in order_factors if not o.contains(o1)]
continue
# 3 or NaN
elif o.is_Number:
if (o is S.NaN or coeff is S.ComplexInfinity and
o.is_finite is False) and not extra:
# we know for sure the result will be nan
return [S.NaN], [], None
if coeff.is_Number or isinstance(coeff, AccumBounds):
coeff += o
if coeff is S.NaN and not extra:
# we know for sure the result will be nan
return [S.NaN], [], None
continue
elif isinstance(o, AccumBounds):
coeff = o.__add__(coeff)
continue
elif isinstance(o, MatrixExpr):
# can't add 0 to Matrix so make sure coeff is not 0
extra.append(o)
continue
elif isinstance(o, TensExpr):
coeff = o.__add__(coeff) if coeff else o
continue
elif o is S.ComplexInfinity:
if coeff.is_finite is False and not extra:
# we know for sure the result will be nan
return [S.NaN], [], None
coeff = S.ComplexInfinity
continue
# Add([...])
elif o.is_Add:
# NB: here we assume Add is always commutative
seq.extend(o.args) # TODO zerocopy?
continue
# Mul([...])
elif o.is_Mul:
c, s = o.as_coeff_Mul()
# check for unevaluated Pow, e.g. 2**3 or 2**(-1/2)
elif o.is_Pow:
b, e = o.as_base_exp()
if b.is_Number and (e.is_Integer or
(e.is_Rational and e.is_negative)):
seq.append(b**e)
continue
c, s = S.One, o
else:
# everything else
c = S.One
s = o
# now we have:
# o = c*s, where
#
# c is a Number
# s is an expression with number factor extracted
# let's collect terms with the same s, so e.g.
# 2*x**2 + 3*x**2 -> 5*x**2
if s in terms:
terms[s] += c
if terms[s] is S.NaN and not extra:
# we know for sure the result will be nan
return [S.NaN], [], None
else:
terms[s] = c
# now let's construct new args:
# [2*x**2, x**3, 7*x**4, pi, ...]
newseq = []
noncommutative = False
for s, c in terms.items():
# 0*s
if c.is_zero:
continue
# 1*s
elif c is S.One:
newseq.append(s)
# c*s
else:
if s.is_Mul:
# Mul, already keeps its arguments in perfect order.
# so we can simply put c in slot0 and go the fast way.
cs = s._new_rawargs(*((c,) + s.args))
newseq.append(cs)
elif s.is_Add:
# we just re-create the unevaluated Mul
newseq.append(Mul(c, s, evaluate=False))
else:
# alternatively we have to call all Mul's machinery (slow)
newseq.append(Mul(c, s))
noncommutative = noncommutative or not s.is_commutative
# oo, -oo
if coeff is S.Infinity:
newseq = [f for f in newseq if not (f.is_extended_nonnegative or f.is_real)]
elif coeff is S.NegativeInfinity:
newseq = [f for f in newseq if not (f.is_extended_nonpositive or f.is_real)]
if coeff is S.ComplexInfinity:
# zoo might be
# infinite_real + finite_im
# finite_real + infinite_im
# infinite_real + infinite_im
# addition of a finite real or imaginary number won't be able to
# change the zoo nature; adding an infinite qualtity would result
# in a NaN condition if it had sign opposite of the infinite
# portion of zoo, e.g., infinite_real - infinite_real.
newseq = [c for c in newseq if not (c.is_finite and
c.is_extended_real is not None)]
# process O(x)
if order_factors:
newseq2 = []
for t in newseq:
for o in order_factors:
# x + O(x) -> O(x)
if o.contains(t):
t = None
break
# x + O(x**2) -> x + O(x**2)
if t is not None:
newseq2.append(t)
newseq = newseq2 + order_factors
# 1 + O(1) -> O(1)
for o in order_factors:
if o.contains(coeff):
coeff = S.Zero
break
# order args canonically
_addsort(newseq)
# current code expects coeff to be first
if coeff is not S.Zero:
newseq.insert(0, coeff)
if extra:
newseq += extra
noncommutative = True
# we are done
if noncommutative:
return [], newseq, None
else:
return newseq, [], None
@classmethod
def class_key(cls):
return 3, 1, cls.__name__
@property
def kind(self):
k = attrgetter('kind')
kinds = map(k, self.args)
kinds = frozenset(kinds)
if len(kinds) != 1:
# Since addition is group operator, kind must be same.
# We know that this is unexpected signature, so return this.
result = UndefinedKind
else:
result, = kinds
return result
def could_extract_minus_sign(self):
return _could_extract_minus_sign(self)
@cacheit
def as_coeff_add(self, *deps):
"""
Returns a tuple (coeff, args) where self is treated as an Add and coeff
is the Number term and args is a tuple of all other terms.
Examples
========
>>> from sympy.abc import x
>>> (7 + 3*x).as_coeff_add()
(7, (3*x,))
>>> (7*x).as_coeff_add()
(0, (7*x,))
"""
if deps:
l1, l2 = sift(self.args, lambda x: x.has_free(*deps), binary=True)
return self._new_rawargs(*l2), tuple(l1)
coeff, notrat = self.args[0].as_coeff_add()
if coeff is not S.Zero:
return coeff, notrat + self.args[1:]
return S.Zero, self.args
def as_coeff_Add(self, rational=False, deps=None):
"""
Efficiently extract the coefficient of a summation.
"""
coeff, args = self.args[0], self.args[1:]
if coeff.is_Number and not rational or coeff.is_Rational:
return coeff, self._new_rawargs(*args)
return S.Zero, self
# Note, we intentionally do not implement Add.as_coeff_mul(). Rather, we
# let Expr.as_coeff_mul() just always return (S.One, self) for an Add. See
# issue 5524.
def _eval_power(self, e):
from .evalf import pure_complex
from .relational import is_eq
if len(self.args) == 2 and any(_.is_infinite for _ in self.args):
if e.is_zero is False and is_eq(e, S.One) is False:
# looking for literal a + I*b
a, b = self.args
if a.coeff(S.ImaginaryUnit):
a, b = b, a
ico = b.coeff(S.ImaginaryUnit)
if ico and ico.is_extended_real and a.is_extended_real:
if e.is_extended_negative:
return S.Zero
if e.is_extended_positive:
return S.ComplexInfinity
return
if e.is_Rational and self.is_number:
ri = pure_complex(self)
if ri:
r, i = ri
if e.q == 2:
from sympy.functions.elementary.miscellaneous import sqrt
D = sqrt(r**2 + i**2)
if D.is_Rational:
from .exprtools import factor_terms
from sympy.functions.elementary.complexes import sign
from .function import expand_multinomial
# (r, i, D) is a Pythagorean triple
root = sqrt(factor_terms((D - r)/2))**e.p
return root*expand_multinomial((
# principle value
(D + r)/abs(i) + sign(i)*S.ImaginaryUnit)**e.p)
elif e == -1:
return _unevaluated_Mul(
r - i*S.ImaginaryUnit,
1/(r**2 + i**2))
elif e.is_Number and abs(e) != 1:
# handle the Float case: (2.0 + 4*x)**e -> 4**e*(0.5 + x)**e
c, m = zip(*[i.as_coeff_Mul() for i in self.args])
if any(i.is_Float for i in c): # XXX should this always be done?
big = -1
for i in c:
if abs(i) >= big:
big = abs(i)
if big > 0 and not equal_valued(big, 1):
from sympy.functions.elementary.complexes import sign
bigs = (big, -big)
c = [sign(i) if i in bigs else i/big for i in c]
addpow = Add(*[c*m for c, m in zip(c, m)])**e
return big**e*addpow
@cacheit
def _eval_derivative(self, s):
return self.func(*[a.diff(s) for a in self.args])
def _eval_nseries(self, x, n, logx, cdir=0):
terms = [t.nseries(x, n=n, logx=logx, cdir=cdir) for t in self.args]
return self.func(*terms)
def _matches_simple(self, expr, repl_dict):
# handle (w+3).matches('x+5') -> {w: x+2}
coeff, terms = self.as_coeff_add()
if len(terms) == 1:
return terms[0].matches(expr - coeff, repl_dict)
return
def matches(self, expr, repl_dict=None, old=False):
return self._matches_commutative(expr, repl_dict, old)
@staticmethod
def _combine_inverse(lhs, rhs):
"""
Returns lhs - rhs, but treats oo like a symbol so oo - oo
returns 0, instead of a nan.
"""
from sympy.simplify.simplify import signsimp
inf = (S.Infinity, S.NegativeInfinity)
if lhs.has(*inf) or rhs.has(*inf):
from .symbol import Dummy
oo = Dummy('oo')
reps = {
S.Infinity: oo,
S.NegativeInfinity: -oo}
ireps = {v: k for k, v in reps.items()}
eq = lhs.xreplace(reps) - rhs.xreplace(reps)
if eq.has(oo):
eq = eq.replace(
lambda x: x.is_Pow and x.base is oo,
lambda x: x.base)
rv = eq.xreplace(ireps)
else:
rv = lhs - rhs
srv = signsimp(rv)
return srv if srv.is_Number else rv
@cacheit
def as_two_terms(self):
"""Return head and tail of self.
This is the most efficient way to get the head and tail of an
expression.
- if you want only the head, use self.args[0];
- if you want to process the arguments of the tail then use
self.as_coef_add() which gives the head and a tuple containing
the arguments of the tail when treated as an Add.
- if you want the coefficient when self is treated as a Mul
then use self.as_coeff_mul()[0]
>>> from sympy.abc import x, y
>>> (3*x - 2*y + 5).as_two_terms()
(5, 3*x - 2*y)
"""
return self.args[0], self._new_rawargs(*self.args[1:])
def as_numer_denom(self):
"""
Decomposes an expression to its numerator part and its
denominator part.
Examples
========
>>> from sympy.abc import x, y, z
>>> (x*y/z).as_numer_denom()
(x*y, z)
>>> (x*(y + 1)/y**7).as_numer_denom()
(x*(y + 1), y**7)
See Also
========
sympy.core.expr.Expr.as_numer_denom
"""
# clear rational denominator
content, expr = self.primitive()
if not isinstance(expr, Add):
return Mul(content, expr, evaluate=False).as_numer_denom()
ncon, dcon = content.as_numer_denom()
# collect numerators and denominators of the terms
nd = defaultdict(list)
for f in expr.args:
ni, di = f.as_numer_denom()
nd[di].append(ni)
# check for quick exit
if len(nd) == 1:
d, n = nd.popitem()
return self.func(
*[_keep_coeff(ncon, ni) for ni in n]), _keep_coeff(dcon, d)
# sum up the terms having a common denominator
for d, n in nd.items():
if len(n) == 1:
nd[d] = n[0]
else:
nd[d] = self.func(*n)
# assemble single numerator and denominator
denoms, numers = [list(i) for i in zip(*iter(nd.items()))]
n, d = self.func(*[Mul(*(denoms[:i] + [numers[i]] + denoms[i + 1:]))
for i in range(len(numers))]), Mul(*denoms)
return _keep_coeff(ncon, n), _keep_coeff(dcon, d)
def _eval_is_polynomial(self, syms):
return all(term._eval_is_polynomial(syms) for term in self.args)
def _eval_is_rational_function(self, syms):
return all(term._eval_is_rational_function(syms) for term in self.args)
def _eval_is_meromorphic(self, x, a):
return _fuzzy_group((arg.is_meromorphic(x, a) for arg in self.args),
quick_exit=True)
def _eval_is_algebraic_expr(self, syms):
return all(term._eval_is_algebraic_expr(syms) for term in self.args)
# assumption methods
_eval_is_real = lambda self: _fuzzy_group(
(a.is_real for a in self.args), quick_exit=True)
_eval_is_extended_real = lambda self: _fuzzy_group(
(a.is_extended_real for a in self.args), quick_exit=True)
_eval_is_complex = lambda self: _fuzzy_group(
(a.is_complex for a in self.args), quick_exit=True)
_eval_is_antihermitian = lambda self: _fuzzy_group(
(a.is_antihermitian for a in self.args), quick_exit=True)
_eval_is_finite = lambda self: _fuzzy_group(
(a.is_finite for a in self.args), quick_exit=True)
_eval_is_hermitian = lambda self: _fuzzy_group(
(a.is_hermitian for a in self.args), quick_exit=True)
_eval_is_integer = lambda self: _fuzzy_group(
(a.is_integer for a in self.args), quick_exit=True)
_eval_is_rational = lambda self: _fuzzy_group(
(a.is_rational for a in self.args), quick_exit=True)
_eval_is_algebraic = lambda self: _fuzzy_group(
(a.is_algebraic for a in self.args), quick_exit=True)
_eval_is_commutative = lambda self: _fuzzy_group(
a.is_commutative for a in self.args)
def _eval_is_infinite(self):
sawinf = False
for a in self.args:
ainf = a.is_infinite
if ainf is None:
return None
elif ainf is True:
# infinite+infinite might not be infinite
if sawinf is True:
return None
sawinf = True
return sawinf
def _eval_is_imaginary(self):
nz = []
im_I = []
for a in self.args:
if a.is_extended_real:
if a.is_zero:
pass
elif a.is_zero is False:
nz.append(a)
else:
return
elif a.is_imaginary:
im_I.append(a*S.ImaginaryUnit)
elif a.is_Mul and S.ImaginaryUnit in a.args:
coeff, ai = a.as_coeff_mul(S.ImaginaryUnit)
if ai == (S.ImaginaryUnit,) and coeff.is_extended_real:
im_I.append(-coeff)
else:
return
else:
return
b = self.func(*nz)
if b != self:
if b.is_zero:
return fuzzy_not(self.func(*im_I).is_zero)
elif b.is_zero is False:
return False
def _eval_is_zero(self):
if self.is_commutative is False:
# issue 10528: there is no way to know if a nc symbol
# is zero or not
return
nz = []
z = 0
im_or_z = False
im = 0
for a in self.args:
if a.is_extended_real:
if a.is_zero:
z += 1
elif a.is_zero is False:
nz.append(a)
else:
return
elif a.is_imaginary:
im += 1
elif a.is_Mul and S.ImaginaryUnit in a.args:
coeff, ai = a.as_coeff_mul(S.ImaginaryUnit)
if ai == (S.ImaginaryUnit,) and coeff.is_extended_real:
im_or_z = True
else:
return
else:
return
if z == len(self.args):
return True
if len(nz) in [0, len(self.args)]:
return None
b = self.func(*nz)
if b.is_zero:
if not im_or_z:
if im == 0:
return True
elif im == 1:
return False
if b.is_zero is False:
return False
def _eval_is_odd(self):
l = [f for f in self.args if not (f.is_even is True)]
if not l:
return False
if l[0].is_odd:
return self._new_rawargs(*l[1:]).is_even
def _eval_is_irrational(self):
for t in self.args:
a = t.is_irrational
if a:
others = list(self.args)
others.remove(t)
if all(x.is_rational is True for x in others):
return True
return None
if a is None:
return
return False
def _all_nonneg_or_nonppos(self):
nn = np = 0
for a in self.args:
if a.is_nonnegative:
if np:
return False
nn = 1
elif a.is_nonpositive:
if nn:
return False
np = 1
else:
break
else:
return True
def _eval_is_extended_positive(self):
if self.is_number:
return super()._eval_is_extended_positive()
c, a = self.as_coeff_Add()
if not c.is_zero:
from .exprtools import _monotonic_sign
v = _monotonic_sign(a)
if v is not None:
s = v + c
if s != self and s.is_extended_positive and a.is_extended_nonnegative:
return True
if len(self.free_symbols) == 1:
v = _monotonic_sign(self)
if v is not None and v != self and v.is_extended_positive:
return True
pos = nonneg = nonpos = unknown_sign = False
saw_INF = set()
args = [a for a in self.args if not a.is_zero]
if not args:
return False
for a in args:
ispos = a.is_extended_positive
infinite = a.is_infinite
if infinite:
saw_INF.add(fuzzy_or((ispos, a.is_extended_nonnegative)))
if True in saw_INF and False in saw_INF:
return
if ispos:
pos = True
continue
elif a.is_extended_nonnegative:
nonneg = True
continue
elif a.is_extended_nonpositive:
nonpos = True
continue
if infinite is None:
return
unknown_sign = True
if saw_INF:
if len(saw_INF) > 1:
return
return saw_INF.pop()
elif unknown_sign:
return
elif not nonpos and not nonneg and pos:
return True
elif not nonpos and pos:
return True
elif not pos and not nonneg:
return False
def _eval_is_extended_nonnegative(self):
if not self.is_number:
c, a = self.as_coeff_Add()
if not c.is_zero and a.is_extended_nonnegative:
from .exprtools import _monotonic_sign
v = _monotonic_sign(a)
if v is not None:
s = v + c
if s != self and s.is_extended_nonnegative:
return True
if len(self.free_symbols) == 1:
v = _monotonic_sign(self)
if v is not None and v != self and v.is_extended_nonnegative:
return True
def _eval_is_extended_nonpositive(self):
if not self.is_number:
c, a = self.as_coeff_Add()
if not c.is_zero and a.is_extended_nonpositive:
from .exprtools import _monotonic_sign
v = _monotonic_sign(a)
if v is not None:
s = v + c
if s != self and s.is_extended_nonpositive:
return True
if len(self.free_symbols) == 1:
v = _monotonic_sign(self)
if v is not None and v != self and v.is_extended_nonpositive:
return True
def _eval_is_extended_negative(self):
if self.is_number:
return super()._eval_is_extended_negative()
c, a = self.as_coeff_Add()
if not c.is_zero:
from .exprtools import _monotonic_sign
v = _monotonic_sign(a)
if v is not None:
s = v + c
if s != self and s.is_extended_negative and a.is_extended_nonpositive:
return True
if len(self.free_symbols) == 1:
v = _monotonic_sign(self)
if v is not None and v != self and v.is_extended_negative:
return True
neg = nonpos = nonneg = unknown_sign = False
saw_INF = set()
args = [a for a in self.args if not a.is_zero]
if not args:
return False
for a in args:
isneg = a.is_extended_negative
infinite = a.is_infinite
if infinite:
saw_INF.add(fuzzy_or((isneg, a.is_extended_nonpositive)))
if True in saw_INF and False in saw_INF:
return
if isneg:
neg = True
continue
elif a.is_extended_nonpositive:
nonpos = True
continue
elif a.is_extended_nonnegative:
nonneg = True
continue
if infinite is None:
return
unknown_sign = True
if saw_INF:
if len(saw_INF) > 1:
return
return saw_INF.pop()
elif unknown_sign:
return
elif not nonneg and not nonpos and neg:
return True
elif not nonneg and neg:
return True
elif not neg and not nonpos:
return False
def _eval_subs(self, old, new):
if not old.is_Add:
if old is S.Infinity and -old in self.args:
# foo - oo is foo + (-oo) internally
return self.xreplace({-old: -new})
return None
coeff_self, terms_self = self.as_coeff_Add()
coeff_old, terms_old = old.as_coeff_Add()
if coeff_self.is_Rational and coeff_old.is_Rational:
if terms_self == terms_old: # (2 + a).subs( 3 + a, y) -> -1 + y
return self.func(new, coeff_self, -coeff_old)
if terms_self == -terms_old: # (2 + a).subs(-3 - a, y) -> -1 - y
return self.func(-new, coeff_self, coeff_old)
if coeff_self.is_Rational and coeff_old.is_Rational \
or coeff_self == coeff_old:
args_old, args_self = self.func.make_args(
terms_old), self.func.make_args(terms_self)
if len(args_old) < len(args_self): # (a+b+c).subs(b+c,x) -> a+x
self_set = set(args_self)
old_set = set(args_old)
if old_set < self_set:
ret_set = self_set - old_set
return self.func(new, coeff_self, -coeff_old,
*[s._subs(old, new) for s in ret_set])
args_old = self.func.make_args(
-terms_old) # (a+b+c+d).subs(-b-c,x) -> a-x+d
old_set = set(args_old)
if old_set < self_set:
ret_set = self_set - old_set
return self.func(-new, coeff_self, coeff_old,
*[s._subs(old, new) for s in ret_set])
def removeO(self):
args = [a for a in self.args if not a.is_Order]
return self._new_rawargs(*args)
def getO(self):
args = [a for a in self.args if a.is_Order]
if args:
return self._new_rawargs(*args)
@cacheit
def extract_leading_order(self, symbols, point=None):
"""
Returns the leading term and its order.
Examples
========
>>> from sympy.abc import x
>>> (x + 1 + 1/x**5).extract_leading_order(x)
((x**(-5), O(x**(-5))),)
>>> (1 + x).extract_leading_order(x)
((1, O(1)),)
>>> (x + x**2).extract_leading_order(x)
((x, O(x)),)
"""
from sympy.series.order import Order
lst = []
symbols = list(symbols if is_sequence(symbols) else [symbols])
if not point:
point = [0]*len(symbols)
seq = [(f, Order(f, *zip(symbols, point))) for f in self.args]
for ef, of in seq:
for e, o in lst:
if o.contains(of) and o != of:
of = None
break
if of is None:
continue
new_lst = [(ef, of)]
for e, o in lst:
if of.contains(o) and o != of:
continue
new_lst.append((e, o))
lst = new_lst
return tuple(lst)
def as_real_imag(self, deep=True, **hints):
"""
Return a tuple representing a complex number.
Examples
========
>>> from sympy import I
>>> (7 + 9*I).as_real_imag()
(7, 9)
>>> ((1 + I)/(1 - I)).as_real_imag()
(0, 1)
>>> ((1 + 2*I)*(1 + 3*I)).as_real_imag()
(-5, 5)
"""
sargs = self.args
re_part, im_part = [], []
for term in sargs:
re, im = term.as_real_imag(deep=deep)
re_part.append(re)
im_part.append(im)
return (self.func(*re_part), self.func(*im_part))
def _eval_as_leading_term(self, x, logx=None, cdir=0):
from sympy.core.symbol import Dummy, Symbol
from sympy.series.order import Order
from sympy.functions.elementary.exponential import log
from sympy.functions.elementary.piecewise import Piecewise, piecewise_fold
from .function import expand_mul
o = self.getO()
if o is None:
o = Order(0)
old = self.removeO()
if old.has(Piecewise):
old = piecewise_fold(old)
# This expansion is the last part of expand_log. expand_log also calls
# expand_mul with factor=True, which would be more expensive
if any(isinstance(a, log) for a in self.args):
logflags = {"deep": True, "log": True, "mul": False, "power_exp": False,
"power_base": False, "multinomial": False, "basic": False, "force": False,
"factor": False}
old = old.expand(**logflags)
expr = expand_mul(old)
if not expr.is_Add:
return expr.as_leading_term(x, logx=logx, cdir=cdir)
infinite = [t for t in expr.args if t.is_infinite]
_logx = Dummy('logx') if logx is None else logx
leading_terms = [t.as_leading_term(x, logx=_logx, cdir=cdir) for t in expr.args]
min, new_expr = Order(0), 0
try:
for term in leading_terms:
order = Order(term, x)
if not min or order not in min:
min = order
new_expr = term
elif min in order:
new_expr += term
except TypeError:
return expr
if logx is None:
new_expr = new_expr.subs(_logx, log(x))
is_zero = new_expr.is_zero
if is_zero is None:
new_expr = new_expr.trigsimp().cancel()
is_zero = new_expr.is_zero
if is_zero is True:
# simple leading term analysis gave us cancelled terms but we have to send
# back a term, so compute the leading term (via series)
try:
n0 = min.getn()
except NotImplementedError:
n0 = S.One
if n0.has(Symbol):
n0 = S.One
res = Order(1)
incr = S.One
while res.is_Order:
res = old._eval_nseries(x, n=n0+incr, logx=logx, cdir=cdir).cancel().powsimp().trigsimp()
incr *= 2
return res.as_leading_term(x, logx=logx, cdir=cdir)
elif new_expr is S.NaN:
return old.func._from_args(infinite) + o
else:
return new_expr
def _eval_adjoint(self):
return self.func(*[t.adjoint() for t in self.args])
def _eval_conjugate(self):
return self.func(*[t.conjugate() for t in self.args])
def _eval_transpose(self):
return self.func(*[t.transpose() for t in self.args])
def primitive(self):
"""
Return ``(R, self/R)`` where ``R``` is the Rational GCD of ``self```.
``R`` is collected only from the leading coefficient of each term.
Examples
========
>>> from sympy.abc import x, y
>>> (2*x + 4*y).primitive()
(2, x + 2*y)
>>> (2*x/3 + 4*y/9).primitive()
(2/9, 3*x + 2*y)
>>> (2*x/3 + 4.2*y).primitive()
(1/3, 2*x + 12.6*y)
No subprocessing of term factors is performed:
>>> ((2 + 2*x)*x + 2).primitive()
(1, x*(2*x + 2) + 2)
Recursive processing can be done with the ``as_content_primitive()``
method:
>>> ((2 + 2*x)*x + 2).as_content_primitive()
(2, x*(x + 1) + 1)
See also: primitive() function in polytools.py
"""
terms = []
inf = False
for a in self.args:
c, m = a.as_coeff_Mul()
if not c.is_Rational:
c = S.One
m = a
inf = inf or m is S.ComplexInfinity
terms.append((c.p, c.q, m))
if not inf:
ngcd = reduce(igcd, [t[0] for t in terms], 0)
dlcm = reduce(ilcm, [t[1] for t in terms], 1)
else:
ngcd = reduce(igcd, [t[0] for t in terms if t[1]], 0)
dlcm = reduce(ilcm, [t[1] for t in terms if t[1]], 1)
if ngcd == dlcm == 1:
return S.One, self
if not inf:
for i, (p, q, term) in enumerate(terms):
terms[i] = _keep_coeff(Rational((p//ngcd)*(dlcm//q)), term)
else:
for i, (p, q, term) in enumerate(terms):
if q:
terms[i] = _keep_coeff(Rational((p//ngcd)*(dlcm//q)), term)
else:
terms[i] = _keep_coeff(Rational(p, q), term)
# we don't need a complete re-flattening since no new terms will join
# so we just use the same sort as is used in Add.flatten. When the
# coefficient changes, the ordering of terms may change, e.g.
# (3*x, 6*y) -> (2*y, x)
#
# We do need to make sure that term[0] stays in position 0, however.
#
if terms[0].is_Number or terms[0] is S.ComplexInfinity:
c = terms.pop(0)
else:
c = None
_addsort(terms)
if c:
terms.insert(0, c)
return Rational(ngcd, dlcm), self._new_rawargs(*terms)
def as_content_primitive(self, radical=False, clear=True):
"""Return the tuple (R, self/R) where R is the positive Rational
extracted from self. If radical is True (default is False) then
common radicals will be removed and included as a factor of the
primitive expression.
Examples
========
>>> from sympy import sqrt
>>> (3 + 3*sqrt(2)).as_content_primitive()
(3, 1 + sqrt(2))
Radical content can also be factored out of the primitive:
>>> (2*sqrt(2) + 4*sqrt(10)).as_content_primitive(radical=True)
(2, sqrt(2)*(1 + 2*sqrt(5)))
See docstring of Expr.as_content_primitive for more examples.
"""
con, prim = self.func(*[_keep_coeff(*a.as_content_primitive(
radical=radical, clear=clear)) for a in self.args]).primitive()
if not clear and not con.is_Integer and prim.is_Add:
con, d = con.as_numer_denom()
_p = prim/d
if any(a.as_coeff_Mul()[0].is_Integer for a in _p.args):
prim = _p
else:
con /= d
if radical and prim.is_Add:
# look for common radicals that can be removed
args = prim.args
rads = []
common_q = None
for m in args:
term_rads = defaultdict(list)
for ai in Mul.make_args(m):
if ai.is_Pow:
b, e = ai.as_base_exp()
if e.is_Rational and b.is_Integer:
term_rads[e.q].append(abs(int(b))**e.p)
if not term_rads:
break
if common_q is None:
common_q = set(term_rads.keys())
else:
common_q = common_q & set(term_rads.keys())
if not common_q:
break
rads.append(term_rads)
else:
# process rads
# keep only those in common_q
for r in rads:
for q in list(r.keys()):
if q not in common_q:
r.pop(q)
for q in r:
r[q] = Mul(*r[q])
# find the gcd of bases for each q
G = []
for q in common_q:
g = reduce(igcd, [r[q] for r in rads], 0)
if g != 1:
G.append(g**Rational(1, q))
if G:
G = Mul(*G)
args = [ai/G for ai in args]
prim = G*prim.func(*args)
return con, prim
@property
def _sorted_args(self):
from .sorting import default_sort_key
return tuple(sorted(self.args, key=default_sort_key))
def _eval_difference_delta(self, n, step):
from sympy.series.limitseq import difference_delta as dd
return self.func(*[dd(a, n, step) for a in self.args])
@property
def _mpc_(self):
"""
Convert self to an mpmath mpc if possible
"""
from .numbers import Float
re_part, rest = self.as_coeff_Add()
im_part, imag_unit = rest.as_coeff_Mul()
if not imag_unit == S.ImaginaryUnit:
# ValueError may seem more reasonable but since it's a @property,
# we need to use AttributeError to keep from confusing things like
# hasattr.
raise AttributeError("Cannot convert Add to mpc. Must be of the form Number + Number*I")
return (Float(re_part)._mpf_, Float(im_part)._mpf_)
def __neg__(self):
if not global_parameters.distribute:
return super().__neg__()
return Mul(S.NegativeOne, self)
add = AssocOpDispatcher('add')
from .mul import Mul, _keep_coeff, _unevaluated_Mul
from .numbers import Rational
PK ]ZZZ�y�
sympy/core/alphabets.pygreeks = ('alpha', 'beta', 'gamma', 'delta', 'epsilon', 'zeta',
'eta', 'theta', 'iota', 'kappa', 'lambda', 'mu', 'nu',
'xi', 'omicron', 'pi', 'rho', 'sigma', 'tau', 'upsilon',
'phi', 'chi', 'psi', 'omega')
PK ]ZZZ��+\ +\ sympy/core/assumptions.py"""
This module contains the machinery handling assumptions.
Do also consider the guide :ref:`assumptions-guide`.
All symbolic objects have assumption attributes that can be accessed via
``.is_<assumption name>`` attribute.
Assumptions determine certain properties of symbolic objects and can
have 3 possible values: ``True``, ``False``, ``None``. ``True`` is returned if the
object has the property and ``False`` is returned if it does not or cannot
(i.e. does not make sense):
>>> from sympy import I
>>> I.is_algebraic
True
>>> I.is_real
False
>>> I.is_prime
False
When the property cannot be determined (or when a method is not
implemented) ``None`` will be returned. For example, a generic symbol, ``x``,
may or may not be positive so a value of ``None`` is returned for ``x.is_positive``.
By default, all symbolic values are in the largest set in the given context
without specifying the property. For example, a symbol that has a property
being integer, is also real, complex, etc.
Here follows a list of possible assumption names:
.. glossary::
commutative
object commutes with any other object with
respect to multiplication operation. See [12]_.
complex
object can have only values from the set
of complex numbers. See [13]_.
imaginary
object value is a number that can be written as a real
number multiplied by the imaginary unit ``I``. See
[3]_. Please note that ``0`` is not considered to be an
imaginary number, see
`issue #7649 <https://github.com/sympy/sympy/issues/7649>`_.
real
object can have only values from the set
of real numbers.
extended_real
object can have only values from the set
of real numbers, ``oo`` and ``-oo``.
integer
object can have only values from the set
of integers.
odd
even
object can have only values from the set of
odd (even) integers [2]_.
prime
object is a natural number greater than 1 that has
no positive divisors other than 1 and itself. See [6]_.
composite
object is a positive integer that has at least one positive
divisor other than 1 or the number itself. See [4]_.
zero
object has the value of 0.
nonzero
object is a real number that is not zero.
rational
object can have only values from the set
of rationals.
algebraic
object can have only values from the set
of algebraic numbers [11]_.
transcendental
object can have only values from the set
of transcendental numbers [10]_.
irrational
object value cannot be represented exactly by :class:`~.Rational`, see [5]_.
finite
infinite
object absolute value is bounded (arbitrarily large).
See [7]_, [8]_, [9]_.
negative
nonnegative
object can have only negative (nonnegative)
values [1]_.
positive
nonpositive
object can have only positive (nonpositive) values.
extended_negative
extended_nonnegative
extended_positive
extended_nonpositive
extended_nonzero
as without the extended part, but also including infinity with
corresponding sign, e.g., extended_positive includes ``oo``
hermitian
antihermitian
object belongs to the field of Hermitian
(antihermitian) operators.
Examples
========
>>> from sympy import Symbol
>>> x = Symbol('x', real=True); x
x
>>> x.is_real
True
>>> x.is_complex
True
See Also
========
.. seealso::
:py:class:`sympy.core.numbers.ImaginaryUnit`
:py:class:`sympy.core.numbers.Zero`
:py:class:`sympy.core.numbers.One`
:py:class:`sympy.core.numbers.Infinity`
:py:class:`sympy.core.numbers.NegativeInfinity`
:py:class:`sympy.core.numbers.ComplexInfinity`
Notes
=====
The fully-resolved assumptions for any SymPy expression
can be obtained as follows:
>>> from sympy.core.assumptions import assumptions
>>> x = Symbol('x',positive=True)
>>> assumptions(x + I)
{'commutative': True, 'complex': True, 'composite': False, 'even':
False, 'extended_negative': False, 'extended_nonnegative': False,
'extended_nonpositive': False, 'extended_nonzero': False,
'extended_positive': False, 'extended_real': False, 'finite': True,
'imaginary': False, 'infinite': False, 'integer': False, 'irrational':
False, 'negative': False, 'noninteger': False, 'nonnegative': False,
'nonpositive': False, 'nonzero': False, 'odd': False, 'positive':
False, 'prime': False, 'rational': False, 'real': False, 'zero':
False}
Developers Notes
================
The current (and possibly incomplete) values are stored
in the ``obj._assumptions dictionary``; queries to getter methods
(with property decorators) or attributes of objects/classes
will return values and update the dictionary.
>>> eq = x**2 + I
>>> eq._assumptions
{}
>>> eq.is_finite
True
>>> eq._assumptions
{'finite': True, 'infinite': False}
For a :class:`~.Symbol`, there are two locations for assumptions that may
be of interest. The ``assumptions0`` attribute gives the full set of
assumptions derived from a given set of initial assumptions. The
latter assumptions are stored as ``Symbol._assumptions_orig``
>>> Symbol('x', prime=True, even=True)._assumptions_orig
{'even': True, 'prime': True}
The ``_assumptions_orig`` are not necessarily canonical nor are they filtered
in any way: they records the assumptions used to instantiate a Symbol and (for
storage purposes) represent a more compact representation of the assumptions
needed to recreate the full set in ``Symbol.assumptions0``.
References
==========
.. [1] https://en.wikipedia.org/wiki/Negative_number
.. [2] https://en.wikipedia.org/wiki/Parity_%28mathematics%29
.. [3] https://en.wikipedia.org/wiki/Imaginary_number
.. [4] https://en.wikipedia.org/wiki/Composite_number
.. [5] https://en.wikipedia.org/wiki/Irrational_number
.. [6] https://en.wikipedia.org/wiki/Prime_number
.. [7] https://en.wikipedia.org/wiki/Finite
.. [8] https://docs.python.org/3/library/math.html#math.isfinite
.. [9] https://numpy.org/doc/stable/reference/generated/numpy.isfinite.html
.. [10] https://en.wikipedia.org/wiki/Transcendental_number
.. [11] https://en.wikipedia.org/wiki/Algebraic_number
.. [12] https://en.wikipedia.org/wiki/Commutative_property
.. [13] https://en.wikipedia.org/wiki/Complex_number
"""
from sympy.utilities.exceptions import sympy_deprecation_warning
from .facts import FactRules, FactKB
from .sympify import sympify
from sympy.core.random import _assumptions_shuffle as shuffle
from sympy.core.assumptions_generated import generated_assumptions as _assumptions
def _load_pre_generated_assumption_rules() -> FactRules:
""" Load the assumption rules from pre-generated data
To update the pre-generated data, see :method::`_generate_assumption_rules`
"""
_assume_rules=FactRules._from_python(_assumptions)
return _assume_rules
def _generate_assumption_rules():
""" Generate the default assumption rules
This method should only be called to update the pre-generated
assumption rules.
To update the pre-generated assumptions run: bin/ask_update.py
"""
_assume_rules = FactRules([
'integer -> rational',
'rational -> real',
'rational -> algebraic',
'algebraic -> complex',
'transcendental == complex & !algebraic',
'real -> hermitian',
'imaginary -> complex',
'imaginary -> antihermitian',
'extended_real -> commutative',
'complex -> commutative',
'complex -> finite',
'odd == integer & !even',
'even == integer & !odd',
'real -> complex',
'extended_real -> real | infinite',
'real == extended_real & finite',
'extended_real == extended_negative | zero | extended_positive',
'extended_negative == extended_nonpositive & extended_nonzero',
'extended_positive == extended_nonnegative & extended_nonzero',
'extended_nonpositive == extended_real & !extended_positive',
'extended_nonnegative == extended_real & !extended_negative',
'real == negative | zero | positive',
'negative == nonpositive & nonzero',
'positive == nonnegative & nonzero',
'nonpositive == real & !positive',
'nonnegative == real & !negative',
'positive == extended_positive & finite',
'negative == extended_negative & finite',
'nonpositive == extended_nonpositive & finite',
'nonnegative == extended_nonnegative & finite',
'nonzero == extended_nonzero & finite',
'zero -> even & finite',
'zero == extended_nonnegative & extended_nonpositive',
'zero == nonnegative & nonpositive',
'nonzero -> real',
'prime -> integer & positive',
'composite -> integer & positive & !prime',
'!composite -> !positive | !even | prime',
'irrational == real & !rational',
'imaginary -> !extended_real',
'infinite == !finite',
'noninteger == extended_real & !integer',
'extended_nonzero == extended_real & !zero',
])
return _assume_rules
_assume_rules = _load_pre_generated_assumption_rules()
_assume_defined = _assume_rules.defined_facts.copy()
_assume_defined.add('polar')
_assume_defined = frozenset(_assume_defined)
def assumptions(expr, _check=None):
"""return the T/F assumptions of ``expr``"""
n = sympify(expr)
if n.is_Symbol:
rv = n.assumptions0 # are any important ones missing?
if _check is not None:
rv = {k: rv[k] for k in set(rv) & set(_check)}
return rv
rv = {}
for k in _assume_defined if _check is None else _check:
v = getattr(n, 'is_{}'.format(k))
if v is not None:
rv[k] = v
return rv
def common_assumptions(exprs, check=None):
"""return those assumptions which have the same True or False
value for all the given expressions.
Examples
========
>>> from sympy.core import common_assumptions
>>> from sympy import oo, pi, sqrt
>>> common_assumptions([-4, 0, sqrt(2), 2, pi, oo])
{'commutative': True, 'composite': False,
'extended_real': True, 'imaginary': False, 'odd': False}
By default, all assumptions are tested; pass an iterable of the
assumptions to limit those that are reported:
>>> common_assumptions([0, 1, 2], ['positive', 'integer'])
{'integer': True}
"""
check = _assume_defined if check is None else set(check)
if not check or not exprs:
return {}
# get all assumptions for each
assume = [assumptions(i, _check=check) for i in sympify(exprs)]
# focus on those of interest that are True
for i, e in enumerate(assume):
assume[i] = {k: e[k] for k in set(e) & check}
# what assumptions are in common?
common = set.intersection(*[set(i) for i in assume])
# which ones hold the same value
a = assume[0]
return {k: a[k] for k in common if all(a[k] == b[k]
for b in assume)}
def failing_assumptions(expr, **assumptions):
"""
Return a dictionary containing assumptions with values not
matching those of the passed assumptions.
Examples
========
>>> from sympy import failing_assumptions, Symbol
>>> x = Symbol('x', positive=True)
>>> y = Symbol('y')
>>> failing_assumptions(6*x + y, positive=True)
{'positive': None}
>>> failing_assumptions(x**2 - 1, positive=True)
{'positive': None}
If *expr* satisfies all of the assumptions, an empty dictionary is returned.
>>> failing_assumptions(x**2, positive=True)
{}
"""
expr = sympify(expr)
failed = {}
for k in assumptions:
test = getattr(expr, 'is_%s' % k, None)
if test is not assumptions[k]:
failed[k] = test
return failed # {} or {assumption: value != desired}
def check_assumptions(expr, against=None, **assume):
"""
Checks whether assumptions of ``expr`` match the T/F assumptions
given (or possessed by ``against``). True is returned if all
assumptions match; False is returned if there is a mismatch and
the assumption in ``expr`` is not None; else None is returned.
Explanation
===========
*assume* is a dict of assumptions with True or False values
Examples
========
>>> from sympy import Symbol, pi, I, exp, check_assumptions
>>> check_assumptions(-5, integer=True)
True
>>> check_assumptions(pi, real=True, integer=False)
True
>>> check_assumptions(pi, negative=True)
False
>>> check_assumptions(exp(I*pi/7), real=False)
True
>>> x = Symbol('x', positive=True)
>>> check_assumptions(2*x + 1, positive=True)
True
>>> check_assumptions(-2*x - 5, positive=True)
False
To check assumptions of *expr* against another variable or expression,
pass the expression or variable as ``against``.
>>> check_assumptions(2*x + 1, x)
True
To see if a number matches the assumptions of an expression, pass
the number as the first argument, else its specific assumptions
may not have a non-None value in the expression:
>>> check_assumptions(x, 3)
>>> check_assumptions(3, x)
True
``None`` is returned if ``check_assumptions()`` could not conclude.
>>> check_assumptions(2*x - 1, x)
>>> z = Symbol('z')
>>> check_assumptions(z, real=True)
See Also
========
failing_assumptions
"""
expr = sympify(expr)
if against is not None:
if assume:
raise ValueError(
'Expecting `against` or `assume`, not both.')
assume = assumptions(against)
known = True
for k, v in assume.items():
if v is None:
continue
e = getattr(expr, 'is_' + k, None)
if e is None:
known = None
elif v != e:
return False
return known
class StdFactKB(FactKB):
"""A FactKB specialized for the built-in rules
This is the only kind of FactKB that Basic objects should use.
"""
def __init__(self, facts=None):
super().__init__(_assume_rules)
# save a copy of the facts dict
if not facts:
self._generator = {}
elif not isinstance(facts, FactKB):
self._generator = facts.copy()
else:
self._generator = facts.generator
if facts:
self.deduce_all_facts(facts)
def copy(self):
return self.__class__(self)
@property
def generator(self):
return self._generator.copy()
def as_property(fact):
"""Convert a fact name to the name of the corresponding property"""
return 'is_%s' % fact
def make_property(fact):
"""Create the automagic property corresponding to a fact."""
def getit(self):
try:
return self._assumptions[fact]
except KeyError:
if self._assumptions is self.default_assumptions:
self._assumptions = self.default_assumptions.copy()
return _ask(fact, self)
getit.func_name = as_property(fact)
return property(getit)
def _ask(fact, obj):
"""
Find the truth value for a property of an object.
This function is called when a request is made to see what a fact
value is.
For this we use several techniques:
First, the fact-evaluation function is tried, if it exists (for
example _eval_is_integer). Then we try related facts. For example
rational --> integer
another example is joined rule:
integer & !odd --> even
so in the latter case if we are looking at what 'even' value is,
'integer' and 'odd' facts will be asked.
In all cases, when we settle on some fact value, its implications are
deduced, and the result is cached in ._assumptions.
"""
# FactKB which is dict-like and maps facts to their known values:
assumptions = obj._assumptions
# A dict that maps facts to their handlers:
handler_map = obj._prop_handler
# This is our queue of facts to check:
facts_to_check = [fact]
facts_queued = {fact}
# Loop over the queue as it extends
for fact_i in facts_to_check:
# If fact_i has already been determined then we don't need to rerun the
# handler. There is a potential race condition for multithreaded code
# though because it's possible that fact_i was checked in another
# thread. The main logic of the loop below would potentially skip
# checking assumptions[fact] in this case so we check it once after the
# loop to be sure.
if fact_i in assumptions:
continue
# Now we call the associated handler for fact_i if it exists.
fact_i_value = None
handler_i = handler_map.get(fact_i)
if handler_i is not None:
fact_i_value = handler_i(obj)
# If we get a new value for fact_i then we should update our knowledge
# of fact_i as well as any related facts that can be inferred using the
# inference rules connecting the fact_i and any other fact values that
# are already known.
if fact_i_value is not None:
assumptions.deduce_all_facts(((fact_i, fact_i_value),))
# Usually if assumptions[fact] is now not None then that is because of
# the call to deduce_all_facts above. The handler for fact_i returned
# True or False and knowing fact_i (which is equal to fact in the first
# iteration) implies knowing a value for fact. It is also possible
# though that independent code e.g. called indirectly by the handler or
# called in another thread in a multithreaded context might have
# resulted in assumptions[fact] being set. Either way we return it.
fact_value = assumptions.get(fact)
if fact_value is not None:
return fact_value
# Extend the queue with other facts that might determine fact_i. Here
# we randomise the order of the facts that are checked. This should not
# lead to any non-determinism if all handlers are logically consistent
# with the inference rules for the facts. Non-deterministic assumptions
# queries can result from bugs in the handlers that are exposed by this
# call to shuffle. These are pushed to the back of the queue meaning
# that the inference graph is traversed in breadth-first order.
new_facts_to_check = list(_assume_rules.prereq[fact_i] - facts_queued)
shuffle(new_facts_to_check)
facts_to_check.extend(new_facts_to_check)
facts_queued.update(new_facts_to_check)
# The above loop should be able to handle everything fine in a
# single-threaded context but in multithreaded code it is possible that
# this thread skipped computing a particular fact that was computed in
# another thread (due to the continue). In that case it is possible that
# fact was inferred and is now stored in the assumptions dict but it wasn't
# checked for in the body of the loop. This is an obscure case but to make
# sure we catch it we check once here at the end of the loop.
if fact in assumptions:
return assumptions[fact]
# This query can not be answered. It's possible that e.g. another thread
# has already stored None for fact but assumptions._tell does not mind if
# we call _tell twice setting the same value. If this raises
# InconsistentAssumptions then it probably means that another thread
# attempted to compute this and got a value of True or False rather than
# None. In that case there must be a bug in at least one of the handlers.
# If the handlers are all deterministic and are consistent with the
# inference rules then the same value should be computed for fact in all
# threads.
assumptions._tell(fact, None)
return None
def _prepare_class_assumptions(cls):
"""Precompute class level assumptions and generate handlers.
This is called by Basic.__init_subclass__ each time a Basic subclass is
defined.
"""
local_defs = {}
for k in _assume_defined:
attrname = as_property(k)
v = cls.__dict__.get(attrname, '')
if isinstance(v, (bool, int, type(None))):
if v is not None:
v = bool(v)
local_defs[k] = v
defs = {}
for base in reversed(cls.__bases__):
assumptions = getattr(base, '_explicit_class_assumptions', None)
if assumptions is not None:
defs.update(assumptions)
defs.update(local_defs)
cls._explicit_class_assumptions = defs
cls.default_assumptions = StdFactKB(defs)
cls._prop_handler = {}
for k in _assume_defined:
eval_is_meth = getattr(cls, '_eval_is_%s' % k, None)
if eval_is_meth is not None:
cls._prop_handler[k] = eval_is_meth
# Put definite results directly into the class dict, for speed
for k, v in cls.default_assumptions.items():
setattr(cls, as_property(k), v)
# protection e.g. for Integer.is_even=F <- (Rational.is_integer=F)
derived_from_bases = set()
for base in cls.__bases__:
default_assumptions = getattr(base, 'default_assumptions', None)
# is an assumption-aware class
if default_assumptions is not None:
derived_from_bases.update(default_assumptions)
for fact in derived_from_bases - set(cls.default_assumptions):
pname = as_property(fact)
if pname not in cls.__dict__:
setattr(cls, pname, make_property(fact))
# Finally, add any missing automagic property (e.g. for Basic)
for fact in _assume_defined:
pname = as_property(fact)
if not hasattr(cls, pname):
setattr(cls, pname, make_property(fact))
# XXX: ManagedProperties used to be the metaclass for Basic but now Basic does
# not use a metaclass. We leave this here for backwards compatibility for now
# in case someone has been using the ManagedProperties class in downstream
# code. The reason that it might have been used is that when subclassing a
# class and wanting to use a metaclass the metaclass must be a subclass of the
# metaclass for the class that is being subclassed. Anyone wanting to subclass
# Basic and use a metaclass in their subclass would have needed to subclass
# ManagedProperties. Here ManagedProperties is not the metaclass for Basic any
# more but it should still be usable as a metaclass for Basic subclasses since
# it is a subclass of type which is now the metaclass for Basic.
class ManagedProperties(type):
def __init__(cls, *args, **kwargs):
msg = ("The ManagedProperties metaclass. "
"Basic does not use metaclasses any more")
sympy_deprecation_warning(msg,
deprecated_since_version="1.12",
active_deprecations_target='managedproperties')
# Here we still call this function in case someone is using
# ManagedProperties for something that is not a Basic subclass. For
# Basic subclasses this function is now called by __init_subclass__ and
# so this metaclass is not needed any more.
_prepare_class_assumptions(cls)
PK ]ZZZ��A� A� # sympy/core/assumptions_generated.py"""
Do NOT manually edit this file.
Instead, run ./bin/ask_update.py.
"""
defined_facts = [
'algebraic',
'antihermitian',
'commutative',
'complex',
'composite',
'even',
'extended_negative',
'extended_nonnegative',
'extended_nonpositive',
'extended_nonzero',
'extended_positive',
'extended_real',
'finite',
'hermitian',
'imaginary',
'infinite',
'integer',
'irrational',
'negative',
'noninteger',
'nonnegative',
'nonpositive',
'nonzero',
'odd',
'positive',
'prime',
'rational',
'real',
'transcendental',
'zero',
] # defined_facts
full_implications = dict( [
# Implications of algebraic = True:
(('algebraic', True), set( (
('commutative', True),
('complex', True),
('finite', True),
('infinite', False),
('transcendental', False),
) ),
),
# Implications of algebraic = False:
(('algebraic', False), set( (
('composite', False),
('even', False),
('integer', False),
('odd', False),
('prime', False),
('rational', False),
('zero', False),
) ),
),
# Implications of antihermitian = True:
(('antihermitian', True), set( (
) ),
),
# Implications of antihermitian = False:
(('antihermitian', False), set( (
('imaginary', False),
) ),
),
# Implications of commutative = True:
(('commutative', True), set( (
) ),
),
# Implications of commutative = False:
(('commutative', False), set( (
('algebraic', False),
('complex', False),
('composite', False),
('even', False),
('extended_negative', False),
('extended_nonnegative', False),
('extended_nonpositive', False),
('extended_nonzero', False),
('extended_positive', False),
('extended_real', False),
('imaginary', False),
('integer', False),
('irrational', False),
('negative', False),
('noninteger', False),
('nonnegative', False),
('nonpositive', False),
('nonzero', False),
('odd', False),
('positive', False),
('prime', False),
('rational', False),
('real', False),
('transcendental', False),
('zero', False),
) ),
),
# Implications of complex = True:
(('complex', True), set( (
('commutative', True),
('finite', True),
('infinite', False),
) ),
),
# Implications of complex = False:
(('complex', False), set( (
('algebraic', False),
('composite', False),
('even', False),
('imaginary', False),
('integer', False),
('irrational', False),
('negative', False),
('nonnegative', False),
('nonpositive', False),
('nonzero', False),
('odd', False),
('positive', False),
('prime', False),
('rational', False),
('real', False),
('transcendental', False),
('zero', False),
) ),
),
# Implications of composite = True:
(('composite', True), set( (
('algebraic', True),
('commutative', True),
('complex', True),
('extended_negative', False),
('extended_nonnegative', True),
('extended_nonpositive', False),
('extended_nonzero', True),
('extended_positive', True),
('extended_real', True),
('finite', True),
('hermitian', True),
('imaginary', False),
('infinite', False),
('integer', True),
('irrational', False),
('negative', False),
('noninteger', False),
('nonnegative', True),
('nonpositive', False),
('nonzero', True),
('positive', True),
('prime', False),
('rational', True),
('real', True),
('transcendental', False),
('zero', False),
) ),
),
# Implications of composite = False:
(('composite', False), set( (
) ),
),
# Implications of even = True:
(('even', True), set( (
('algebraic', True),
('commutative', True),
('complex', True),
('extended_real', True),
('finite', True),
('hermitian', True),
('imaginary', False),
('infinite', False),
('integer', True),
('irrational', False),
('noninteger', False),
('odd', False),
('rational', True),
('real', True),
('transcendental', False),
) ),
),
# Implications of even = False:
(('even', False), set( (
('zero', False),
) ),
),
# Implications of extended_negative = True:
(('extended_negative', True), set( (
('commutative', True),
('composite', False),
('extended_nonnegative', False),
('extended_nonpositive', True),
('extended_nonzero', True),
('extended_positive', False),
('extended_real', True),
('imaginary', False),
('nonnegative', False),
('positive', False),
('prime', False),
('zero', False),
) ),
),
# Implications of extended_negative = False:
(('extended_negative', False), set( (
('negative', False),
) ),
),
# Implications of extended_nonnegative = True:
(('extended_nonnegative', True), set( (
('commutative', True),
('extended_negative', False),
('extended_real', True),
('imaginary', False),
('negative', False),
) ),
),
# Implications of extended_nonnegative = False:
(('extended_nonnegative', False), set( (
('composite', False),
('extended_positive', False),
('nonnegative', False),
('positive', False),
('prime', False),
('zero', False),
) ),
),
# Implications of extended_nonpositive = True:
(('extended_nonpositive', True), set( (
('commutative', True),
('composite', False),
('extended_positive', False),
('extended_real', True),
('imaginary', False),
('positive', False),
('prime', False),
) ),
),
# Implications of extended_nonpositive = False:
(('extended_nonpositive', False), set( (
('extended_negative', False),
('negative', False),
('nonpositive', False),
('zero', False),
) ),
),
# Implications of extended_nonzero = True:
(('extended_nonzero', True), set( (
('commutative', True),
('extended_real', True),
('imaginary', False),
('zero', False),
) ),
),
# Implications of extended_nonzero = False:
(('extended_nonzero', False), set( (
('composite', False),
('extended_negative', False),
('extended_positive', False),
('negative', False),
('nonzero', False),
('positive', False),
('prime', False),
) ),
),
# Implications of extended_positive = True:
(('extended_positive', True), set( (
('commutative', True),
('extended_negative', False),
('extended_nonnegative', True),
('extended_nonpositive', False),
('extended_nonzero', True),
('extended_real', True),
('imaginary', False),
('negative', False),
('nonpositive', False),
('zero', False),
) ),
),
# Implications of extended_positive = False:
(('extended_positive', False), set( (
('composite', False),
('positive', False),
('prime', False),
) ),
),
# Implications of extended_real = True:
(('extended_real', True), set( (
('commutative', True),
('imaginary', False),
) ),
),
# Implications of extended_real = False:
(('extended_real', False), set( (
('composite', False),
('even', False),
('extended_negative', False),
('extended_nonnegative', False),
('extended_nonpositive', False),
('extended_nonzero', False),
('extended_positive', False),
('integer', False),
('irrational', False),
('negative', False),
('noninteger', False),
('nonnegative', False),
('nonpositive', False),
('nonzero', False),
('odd', False),
('positive', False),
('prime', False),
('rational', False),
('real', False),
('zero', False),
) ),
),
# Implications of finite = True:
(('finite', True), set( (
('infinite', False),
) ),
),
# Implications of finite = False:
(('finite', False), set( (
('algebraic', False),
('complex', False),
('composite', False),
('even', False),
('imaginary', False),
('infinite', True),
('integer', False),
('irrational', False),
('negative', False),
('nonnegative', False),
('nonpositive', False),
('nonzero', False),
('odd', False),
('positive', False),
('prime', False),
('rational', False),
('real', False),
('transcendental', False),
('zero', False),
) ),
),
# Implications of hermitian = True:
(('hermitian', True), set( (
) ),
),
# Implications of hermitian = False:
(('hermitian', False), set( (
('composite', False),
('even', False),
('integer', False),
('irrational', False),
('negative', False),
('nonnegative', False),
('nonpositive', False),
('nonzero', False),
('odd', False),
('positive', False),
('prime', False),
('rational', False),
('real', False),
('zero', False),
) ),
),
# Implications of imaginary = True:
(('imaginary', True), set( (
('antihermitian', True),
('commutative', True),
('complex', True),
('composite', False),
('even', False),
('extended_negative', False),
('extended_nonnegative', False),
('extended_nonpositive', False),
('extended_nonzero', False),
('extended_positive', False),
('extended_real', False),
('finite', True),
('infinite', False),
('integer', False),
('irrational', False),
('negative', False),
('noninteger', False),
('nonnegative', False),
('nonpositive', False),
('nonzero', False),
('odd', False),
('positive', False),
('prime', False),
('rational', False),
('real', False),
('zero', False),
) ),
),
# Implications of imaginary = False:
(('imaginary', False), set( (
) ),
),
# Implications of infinite = True:
(('infinite', True), set( (
('algebraic', False),
('complex', False),
('composite', False),
('even', False),
('finite', False),
('imaginary', False),
('integer', False),
('irrational', False),
('negative', False),
('nonnegative', False),
('nonpositive', False),
('nonzero', False),
('odd', False),
('positive', False),
('prime', False),
('rational', False),
('real', False),
('transcendental', False),
('zero', False),
) ),
),
# Implications of infinite = False:
(('infinite', False), set( (
('finite', True),
) ),
),
# Implications of integer = True:
(('integer', True), set( (
('algebraic', True),
('commutative', True),
('complex', True),
('extended_real', True),
('finite', True),
('hermitian', True),
('imaginary', False),
('infinite', False),
('irrational', False),
('noninteger', False),
('rational', True),
('real', True),
('transcendental', False),
) ),
),
# Implications of integer = False:
(('integer', False), set( (
('composite', False),
('even', False),
('odd', False),
('prime', False),
('zero', False),
) ),
),
# Implications of irrational = True:
(('irrational', True), set( (
('commutative', True),
('complex', True),
('composite', False),
('even', False),
('extended_nonzero', True),
('extended_real', True),
('finite', True),
('hermitian', True),
('imaginary', False),
('infinite', False),
('integer', False),
('noninteger', True),
('nonzero', True),
('odd', False),
('prime', False),
('rational', False),
('real', True),
('zero', False),
) ),
),
# Implications of irrational = False:
(('irrational', False), set( (
) ),
),
# Implications of negative = True:
(('negative', True), set( (
('commutative', True),
('complex', True),
('composite', False),
('extended_negative', True),
('extended_nonnegative', False),
('extended_nonpositive', True),
('extended_nonzero', True),
('extended_positive', False),
('extended_real', True),
('finite', True),
('hermitian', True),
('imaginary', False),
('infinite', False),
('nonnegative', False),
('nonpositive', True),
('nonzero', True),
('positive', False),
('prime', False),
('real', True),
('zero', False),
) ),
),
# Implications of negative = False:
(('negative', False), set( (
) ),
),
# Implications of noninteger = True:
(('noninteger', True), set( (
('commutative', True),
('composite', False),
('even', False),
('extended_nonzero', True),
('extended_real', True),
('imaginary', False),
('integer', False),
('odd', False),
('prime', False),
('zero', False),
) ),
),
# Implications of noninteger = False:
(('noninteger', False), set( (
) ),
),
# Implications of nonnegative = True:
(('nonnegative', True), set( (
('commutative', True),
('complex', True),
('extended_negative', False),
('extended_nonnegative', True),
('extended_real', True),
('finite', True),
('hermitian', True),
('imaginary', False),
('infinite', False),
('negative', False),
('real', True),
) ),
),
# Implications of nonnegative = False:
(('nonnegative', False), set( (
('composite', False),
('positive', False),
('prime', False),
('zero', False),
) ),
),
# Implications of nonpositive = True:
(('nonpositive', True), set( (
('commutative', True),
('complex', True),
('composite', False),
('extended_nonpositive', True),
('extended_positive', False),
('extended_real', True),
('finite', True),
('hermitian', True),
('imaginary', False),
('infinite', False),
('positive', False),
('prime', False),
('real', True),
) ),
),
# Implications of nonpositive = False:
(('nonpositive', False), set( (
('negative', False),
('zero', False),
) ),
),
# Implications of nonzero = True:
(('nonzero', True), set( (
('commutative', True),
('complex', True),
('extended_nonzero', True),
('extended_real', True),
('finite', True),
('hermitian', True),
('imaginary', False),
('infinite', False),
('real', True),
('zero', False),
) ),
),
# Implications of nonzero = False:
(('nonzero', False), set( (
('composite', False),
('negative', False),
('positive', False),
('prime', False),
) ),
),
# Implications of odd = True:
(('odd', True), set( (
('algebraic', True),
('commutative', True),
('complex', True),
('even', False),
('extended_nonzero', True),
('extended_real', True),
('finite', True),
('hermitian', True),
('imaginary', False),
('infinite', False),
('integer', True),
('irrational', False),
('noninteger', False),
('nonzero', True),
('rational', True),
('real', True),
('transcendental', False),
('zero', False),
) ),
),
# Implications of odd = False:
(('odd', False), set( (
) ),
),
# Implications of positive = True:
(('positive', True), set( (
('commutative', True),
('complex', True),
('extended_negative', False),
('extended_nonnegative', True),
('extended_nonpositive', False),
('extended_nonzero', True),
('extended_positive', True),
('extended_real', True),
('finite', True),
('hermitian', True),
('imaginary', False),
('infinite', False),
('negative', False),
('nonnegative', True),
('nonpositive', False),
('nonzero', True),
('real', True),
('zero', False),
) ),
),
# Implications of positive = False:
(('positive', False), set( (
('composite', False),
('prime', False),
) ),
),
# Implications of prime = True:
(('prime', True), set( (
('algebraic', True),
('commutative', True),
('complex', True),
('composite', False),
('extended_negative', False),
('extended_nonnegative', True),
('extended_nonpositive', False),
('extended_nonzero', True),
('extended_positive', True),
('extended_real', True),
('finite', True),
('hermitian', True),
('imaginary', False),
('infinite', False),
('integer', True),
('irrational', False),
('negative', False),
('noninteger', False),
('nonnegative', True),
('nonpositive', False),
('nonzero', True),
('positive', True),
('rational', True),
('real', True),
('transcendental', False),
('zero', False),
) ),
),
# Implications of prime = False:
(('prime', False), set( (
) ),
),
# Implications of rational = True:
(('rational', True), set( (
('algebraic', True),
('commutative', True),
('complex', True),
('extended_real', True),
('finite', True),
('hermitian', True),
('imaginary', False),
('infinite', False),
('irrational', False),
('real', True),
('transcendental', False),
) ),
),
# Implications of rational = False:
(('rational', False), set( (
('composite', False),
('even', False),
('integer', False),
('odd', False),
('prime', False),
('zero', False),
) ),
),
# Implications of real = True:
(('real', True), set( (
('commutative', True),
('complex', True),
('extended_real', True),
('finite', True),
('hermitian', True),
('imaginary', False),
('infinite', False),
) ),
),
# Implications of real = False:
(('real', False), set( (
('composite', False),
('even', False),
('integer', False),
('irrational', False),
('negative', False),
('nonnegative', False),
('nonpositive', False),
('nonzero', False),
('odd', False),
('positive', False),
('prime', False),
('rational', False),
('zero', False),
) ),
),
# Implications of transcendental = True:
(('transcendental', True), set( (
('algebraic', False),
('commutative', True),
('complex', True),
('composite', False),
('even', False),
('finite', True),
('infinite', False),
('integer', False),
('odd', False),
('prime', False),
('rational', False),
('zero', False),
) ),
),
# Implications of transcendental = False:
(('transcendental', False), set( (
) ),
),
# Implications of zero = True:
(('zero', True), set( (
('algebraic', True),
('commutative', True),
('complex', True),
('composite', False),
('even', True),
('extended_negative', False),
('extended_nonnegative', True),
('extended_nonpositive', True),
('extended_nonzero', False),
('extended_positive', False),
('extended_real', True),
('finite', True),
('hermitian', True),
('imaginary', False),
('infinite', False),
('integer', True),
('irrational', False),
('negative', False),
('noninteger', False),
('nonnegative', True),
('nonpositive', True),
('nonzero', False),
('odd', False),
('positive', False),
('prime', False),
('rational', True),
('real', True),
('transcendental', False),
) ),
),
# Implications of zero = False:
(('zero', False), set( (
) ),
),
] ) # full_implications
prereq = {
# facts that could determine the value of algebraic
'algebraic': {
'commutative',
'complex',
'composite',
'even',
'finite',
'infinite',
'integer',
'odd',
'prime',
'rational',
'transcendental',
'zero',
},
# facts that could determine the value of antihermitian
'antihermitian': {
'imaginary',
},
# facts that could determine the value of commutative
'commutative': {
'algebraic',
'complex',
'composite',
'even',
'extended_negative',
'extended_nonnegative',
'extended_nonpositive',
'extended_nonzero',
'extended_positive',
'extended_real',
'imaginary',
'integer',
'irrational',
'negative',
'noninteger',
'nonnegative',
'nonpositive',
'nonzero',
'odd',
'positive',
'prime',
'rational',
'real',
'transcendental',
'zero',
},
# facts that could determine the value of complex
'complex': {
'algebraic',
'commutative',
'composite',
'even',
'finite',
'imaginary',
'infinite',
'integer',
'irrational',
'negative',
'nonnegative',
'nonpositive',
'nonzero',
'odd',
'positive',
'prime',
'rational',
'real',
'transcendental',
'zero',
},
# facts that could determine the value of composite
'composite': {
'algebraic',
'commutative',
'complex',
'extended_negative',
'extended_nonnegative',
'extended_nonpositive',
'extended_nonzero',
'extended_positive',
'extended_real',
'finite',
'hermitian',
'imaginary',
'infinite',
'integer',
'irrational',
'negative',
'noninteger',
'nonnegative',
'nonpositive',
'nonzero',
'positive',
'prime',
'rational',
'real',
'transcendental',
'zero',
},
# facts that could determine the value of even
'even': {
'algebraic',
'commutative',
'complex',
'extended_real',
'finite',
'hermitian',
'imaginary',
'infinite',
'integer',
'irrational',
'noninteger',
'odd',
'rational',
'real',
'transcendental',
'zero',
},
# facts that could determine the value of extended_negative
'extended_negative': {
'commutative',
'composite',
'extended_nonnegative',
'extended_nonpositive',
'extended_nonzero',
'extended_positive',
'extended_real',
'imaginary',
'negative',
'nonnegative',
'positive',
'prime',
'zero',
},
# facts that could determine the value of extended_nonnegative
'extended_nonnegative': {
'commutative',
'composite',
'extended_negative',
'extended_positive',
'extended_real',
'imaginary',
'negative',
'nonnegative',
'positive',
'prime',
'zero',
},
# facts that could determine the value of extended_nonpositive
'extended_nonpositive': {
'commutative',
'composite',
'extended_negative',
'extended_positive',
'extended_real',
'imaginary',
'negative',
'nonpositive',
'positive',
'prime',
'zero',
},
# facts that could determine the value of extended_nonzero
'extended_nonzero': {
'commutative',
'composite',
'extended_negative',
'extended_positive',
'extended_real',
'imaginary',
'irrational',
'negative',
'noninteger',
'nonzero',
'odd',
'positive',
'prime',
'zero',
},
# facts that could determine the value of extended_positive
'extended_positive': {
'commutative',
'composite',
'extended_negative',
'extended_nonnegative',
'extended_nonpositive',
'extended_nonzero',
'extended_real',
'imaginary',
'negative',
'nonpositive',
'positive',
'prime',
'zero',
},
# facts that could determine the value of extended_real
'extended_real': {
'commutative',
'composite',
'even',
'extended_negative',
'extended_nonnegative',
'extended_nonpositive',
'extended_nonzero',
'extended_positive',
'imaginary',
'integer',
'irrational',
'negative',
'noninteger',
'nonnegative',
'nonpositive',
'nonzero',
'odd',
'positive',
'prime',
'rational',
'real',
'zero',
},
# facts that could determine the value of finite
'finite': {
'algebraic',
'complex',
'composite',
'even',
'imaginary',
'infinite',
'integer',
'irrational',
'negative',
'nonnegative',
'nonpositive',
'nonzero',
'odd',
'positive',
'prime',
'rational',
'real',
'transcendental',
'zero',
},
# facts that could determine the value of hermitian
'hermitian': {
'composite',
'even',
'integer',
'irrational',
'negative',
'nonnegative',
'nonpositive',
'nonzero',
'odd',
'positive',
'prime',
'rational',
'real',
'zero',
},
# facts that could determine the value of imaginary
'imaginary': {
'antihermitian',
'commutative',
'complex',
'composite',
'even',
'extended_negative',
'extended_nonnegative',
'extended_nonpositive',
'extended_nonzero',
'extended_positive',
'extended_real',
'finite',
'infinite',
'integer',
'irrational',
'negative',
'noninteger',
'nonnegative',
'nonpositive',
'nonzero',
'odd',
'positive',
'prime',
'rational',
'real',
'zero',
},
# facts that could determine the value of infinite
'infinite': {
'algebraic',
'complex',
'composite',
'even',
'finite',
'imaginary',
'integer',
'irrational',
'negative',
'nonnegative',
'nonpositive',
'nonzero',
'odd',
'positive',
'prime',
'rational',
'real',
'transcendental',
'zero',
},
# facts that could determine the value of integer
'integer': {
'algebraic',
'commutative',
'complex',
'composite',
'even',
'extended_real',
'finite',
'hermitian',
'imaginary',
'infinite',
'irrational',
'noninteger',
'odd',
'prime',
'rational',
'real',
'transcendental',
'zero',
},
# facts that could determine the value of irrational
'irrational': {
'commutative',
'complex',
'composite',
'even',
'extended_real',
'finite',
'hermitian',
'imaginary',
'infinite',
'integer',
'odd',
'prime',
'rational',
'real',
'zero',
},
# facts that could determine the value of negative
'negative': {
'commutative',
'complex',
'composite',
'extended_negative',
'extended_nonnegative',
'extended_nonpositive',
'extended_nonzero',
'extended_positive',
'extended_real',
'finite',
'hermitian',
'imaginary',
'infinite',
'nonnegative',
'nonpositive',
'nonzero',
'positive',
'prime',
'real',
'zero',
},
# facts that could determine the value of noninteger
'noninteger': {
'commutative',
'composite',
'even',
'extended_real',
'imaginary',
'integer',
'irrational',
'odd',
'prime',
'zero',
},
# facts that could determine the value of nonnegative
'nonnegative': {
'commutative',
'complex',
'composite',
'extended_negative',
'extended_nonnegative',
'extended_real',
'finite',
'hermitian',
'imaginary',
'infinite',
'negative',
'positive',
'prime',
'real',
'zero',
},
# facts that could determine the value of nonpositive
'nonpositive': {
'commutative',
'complex',
'composite',
'extended_nonpositive',
'extended_positive',
'extended_real',
'finite',
'hermitian',
'imaginary',
'infinite',
'negative',
'positive',
'prime',
'real',
'zero',
},
# facts that could determine the value of nonzero
'nonzero': {
'commutative',
'complex',
'composite',
'extended_nonzero',
'extended_real',
'finite',
'hermitian',
'imaginary',
'infinite',
'irrational',
'negative',
'odd',
'positive',
'prime',
'real',
'zero',
},
# facts that could determine the value of odd
'odd': {
'algebraic',
'commutative',
'complex',
'even',
'extended_real',
'finite',
'hermitian',
'imaginary',
'infinite',
'integer',
'irrational',
'noninteger',
'rational',
'real',
'transcendental',
'zero',
},
# facts that could determine the value of positive
'positive': {
'commutative',
'complex',
'composite',
'extended_negative',
'extended_nonnegative',
'extended_nonpositive',
'extended_nonzero',
'extended_positive',
'extended_real',
'finite',
'hermitian',
'imaginary',
'infinite',
'negative',
'nonnegative',
'nonpositive',
'nonzero',
'prime',
'real',
'zero',
},
# facts that could determine the value of prime
'prime': {
'algebraic',
'commutative',
'complex',
'composite',
'extended_negative',
'extended_nonnegative',
'extended_nonpositive',
'extended_nonzero',
'extended_positive',
'extended_real',
'finite',
'hermitian',
'imaginary',
'infinite',
'integer',
'irrational',
'negative',
'noninteger',
'nonnegative',
'nonpositive',
'nonzero',
'positive',
'rational',
'real',
'transcendental',
'zero',
},
# facts that could determine the value of rational
'rational': {
'algebraic',
'commutative',
'complex',
'composite',
'even',
'extended_real',
'finite',
'hermitian',
'imaginary',
'infinite',
'integer',
'irrational',
'odd',
'prime',
'real',
'transcendental',
'zero',
},
# facts that could determine the value of real
'real': {
'commutative',
'complex',
'composite',
'even',
'extended_real',
'finite',
'hermitian',
'imaginary',
'infinite',
'integer',
'irrational',
'negative',
'nonnegative',
'nonpositive',
'nonzero',
'odd',
'positive',
'prime',
'rational',
'zero',
},
# facts that could determine the value of transcendental
'transcendental': {
'algebraic',
'commutative',
'complex',
'composite',
'even',
'finite',
'infinite',
'integer',
'odd',
'prime',
'rational',
'zero',
},
# facts that could determine the value of zero
'zero': {
'algebraic',
'commutative',
'complex',
'composite',
'even',
'extended_negative',
'extended_nonnegative',
'extended_nonpositive',
'extended_nonzero',
'extended_positive',
'extended_real',
'finite',
'hermitian',
'imaginary',
'infinite',
'integer',
'irrational',
'negative',
'noninteger',
'nonnegative',
'nonpositive',
'nonzero',
'odd',
'positive',
'prime',
'rational',
'real',
'transcendental',
},
} # prereq
# Note: the order of the beta rules is used in the beta_triggers
beta_rules = [
# Rules implying composite = True
({('even', True), ('positive', True), ('prime', False)},
('composite', True)),
# Rules implying even = False
({('composite', False), ('positive', True), ('prime', False)},
('even', False)),
# Rules implying even = True
({('integer', True), ('odd', False)},
('even', True)),
# Rules implying extended_negative = True
({('extended_positive', False), ('extended_real', True), ('zero', False)},
('extended_negative', True)),
({('extended_nonpositive', True), ('extended_nonzero', True)},
('extended_negative', True)),
# Rules implying extended_nonnegative = True
({('extended_negative', False), ('extended_real', True)},
('extended_nonnegative', True)),
# Rules implying extended_nonpositive = True
({('extended_positive', False), ('extended_real', True)},
('extended_nonpositive', True)),
# Rules implying extended_nonzero = True
({('extended_real', True), ('zero', False)},
('extended_nonzero', True)),
# Rules implying extended_positive = True
({('extended_negative', False), ('extended_real', True), ('zero', False)},
('extended_positive', True)),
({('extended_nonnegative', True), ('extended_nonzero', True)},
('extended_positive', True)),
# Rules implying extended_real = False
({('infinite', False), ('real', False)},
('extended_real', False)),
({('extended_negative', False), ('extended_positive', False), ('zero', False)},
('extended_real', False)),
# Rules implying infinite = True
({('extended_real', True), ('real', False)},
('infinite', True)),
# Rules implying irrational = True
({('rational', False), ('real', True)},
('irrational', True)),
# Rules implying negative = True
({('positive', False), ('real', True), ('zero', False)},
('negative', True)),
({('nonpositive', True), ('nonzero', True)},
('negative', True)),
({('extended_negative', True), ('finite', True)},
('negative', True)),
# Rules implying noninteger = True
({('extended_real', True), ('integer', False)},
('noninteger', True)),
# Rules implying nonnegative = True
({('negative', False), ('real', True)},
('nonnegative', True)),
({('extended_nonnegative', True), ('finite', True)},
('nonnegative', True)),
# Rules implying nonpositive = True
({('positive', False), ('real', True)},
('nonpositive', True)),
({('extended_nonpositive', True), ('finite', True)},
('nonpositive', True)),
# Rules implying nonzero = True
({('extended_nonzero', True), ('finite', True)},
('nonzero', True)),
# Rules implying odd = True
({('even', False), ('integer', True)},
('odd', True)),
# Rules implying positive = False
({('composite', False), ('even', True), ('prime', False)},
('positive', False)),
# Rules implying positive = True
({('negative', False), ('real', True), ('zero', False)},
('positive', True)),
({('nonnegative', True), ('nonzero', True)},
('positive', True)),
({('extended_positive', True), ('finite', True)},
('positive', True)),
# Rules implying prime = True
({('composite', False), ('even', True), ('positive', True)},
('prime', True)),
# Rules implying real = False
({('negative', False), ('positive', False), ('zero', False)},
('real', False)),
# Rules implying real = True
({('extended_real', True), ('infinite', False)},
('real', True)),
({('extended_real', True), ('finite', True)},
('real', True)),
# Rules implying transcendental = True
({('algebraic', False), ('complex', True)},
('transcendental', True)),
# Rules implying zero = True
({('extended_negative', False), ('extended_positive', False), ('extended_real', True)},
('zero', True)),
({('negative', False), ('positive', False), ('real', True)},
('zero', True)),
({('extended_nonnegative', True), ('extended_nonpositive', True)},
('zero', True)),
({('nonnegative', True), ('nonpositive', True)},
('zero', True)),
] # beta_rules
beta_triggers = {
('algebraic', False): [32, 11, 3, 8, 29, 14, 25, 13, 17, 7],
('algebraic', True): [10, 30, 31, 27, 16, 21, 19, 22],
('antihermitian', False): [],
('commutative', False): [],
('complex', False): [10, 12, 11, 3, 8, 17, 7],
('complex', True): [32, 10, 30, 31, 27, 16, 21, 19, 22],
('composite', False): [1, 28, 24],
('composite', True): [23, 2],
('even', False): [23, 11, 3, 8, 29, 14, 25, 7],
('even', True): [3, 33, 8, 6, 5, 14, 34, 25, 20, 18, 27, 16, 21, 19, 22, 0, 28, 24, 7],
('extended_negative', False): [11, 33, 8, 5, 29, 34, 25, 18],
('extended_negative', True): [30, 12, 31, 29, 14, 20, 16, 21, 22, 17],
('extended_nonnegative', False): [11, 3, 6, 29, 14, 20, 7],
('extended_nonnegative', True): [30, 12, 31, 33, 8, 9, 6, 29, 34, 25, 18, 19, 35, 17, 7],
('extended_nonpositive', False): [11, 8, 5, 29, 25, 18, 7],
('extended_nonpositive', True): [30, 12, 31, 3, 33, 4, 5, 29, 14, 34, 20, 21, 35, 17, 7],
('extended_nonzero', False): [11, 33, 6, 5, 29, 34, 20, 18],
('extended_nonzero', True): [30, 12, 31, 3, 8, 4, 9, 6, 5, 29, 14, 25, 22, 17],
('extended_positive', False): [11, 3, 33, 6, 29, 14, 34, 20],
('extended_positive', True): [30, 12, 31, 29, 25, 18, 27, 19, 22, 17],
('extended_real', False): [],
('extended_real', True): [30, 12, 31, 3, 33, 8, 6, 5, 17, 7],
('finite', False): [11, 3, 8, 17, 7],
('finite', True): [10, 30, 31, 27, 16, 21, 19, 22],
('hermitian', False): [10, 12, 11, 3, 8, 17, 7],
('imaginary', True): [32],
('infinite', False): [10, 30, 31, 27, 16, 21, 19, 22],
('infinite', True): [11, 3, 8, 17, 7],
('integer', False): [11, 3, 8, 29, 14, 25, 17, 7],
('integer', True): [23, 2, 3, 33, 8, 6, 5, 14, 34, 25, 20, 18, 27, 16, 21, 19, 22, 7],
('irrational', True): [32, 3, 8, 4, 9, 6, 5, 14, 25, 15, 26, 20, 18, 27, 16, 21, 19],
('negative', False): [29, 34, 25, 18],
('negative', True): [32, 13, 17],
('noninteger', True): [30, 12, 31, 3, 8, 4, 9, 6, 5, 29, 14, 25, 22],
('nonnegative', False): [11, 3, 8, 29, 14, 20, 7],
('nonnegative', True): [32, 33, 8, 9, 6, 34, 25, 26, 20, 27, 21, 22, 35, 36, 13, 17, 7],
('nonpositive', False): [11, 3, 8, 29, 25, 18, 7],
('nonpositive', True): [32, 3, 33, 4, 5, 14, 34, 15, 18, 16, 19, 22, 35, 36, 13, 17, 7],
('nonzero', False): [29, 34, 20, 18],
('nonzero', True): [32, 3, 8, 4, 9, 6, 5, 14, 25, 15, 26, 20, 18, 27, 16, 21, 19, 13, 17],
('odd', False): [2],
('odd', True): [3, 8, 4, 9, 6, 5, 14, 25, 15, 26, 20, 18, 27, 16, 21, 19],
('positive', False): [29, 14, 34, 20],
('positive', True): [32, 0, 1, 28, 13, 17],
('prime', False): [0, 1, 24],
('prime', True): [23, 2],
('rational', False): [11, 3, 8, 29, 14, 25, 13, 17, 7],
('rational', True): [3, 33, 8, 6, 5, 14, 34, 25, 20, 18, 27, 16, 21, 19, 22, 17, 7],
('real', False): [10, 12, 11, 3, 8, 17, 7],
('real', True): [32, 3, 33, 8, 6, 5, 14, 34, 25, 20, 18, 27, 16, 21, 19, 22, 13, 17, 7],
('transcendental', True): [10, 30, 31, 11, 3, 8, 29, 14, 25, 27, 16, 21, 19, 22, 13, 17, 7],
('zero', False): [11, 3, 8, 29, 14, 25, 7],
('zero', True): [],
} # beta_triggers
generated_assumptions = {'defined_facts': defined_facts, 'full_implications': full_implications,
'prereq': prereq, 'beta_rules': beta_rules, 'beta_triggers': beta_triggers}
PK ]ZZZ�C�� � sympy/core/backend.pyimport os
USE_SYMENGINE = os.getenv('USE_SYMENGINE', '0')
USE_SYMENGINE = USE_SYMENGINE.lower() in ('1', 't', 'true') # type: ignore
if USE_SYMENGINE:
from symengine import (Symbol, Integer, sympify as sympify_symengine, S,
SympifyError, exp, log, gamma, sqrt, I, E, pi, Matrix,
sin, cos, tan, cot, csc, sec, asin, acos, atan, acot, acsc, asec,
sinh, cosh, tanh, coth, asinh, acosh, atanh, acoth,
lambdify, symarray, diff, zeros, eye, diag, ones,
expand, Function, symbols, var, Add, Mul, Derivative,
ImmutableMatrix, MatrixBase, Rational, Basic)
from symengine.lib.symengine_wrapper import gcd as igcd
from symengine import AppliedUndef
def sympify(a, *, strict=False):
"""
Notes
=====
SymEngine's ``sympify`` does not accept keyword arguments and is
therefore not compatible with SymPy's ``sympify`` with ``strict=True``
(which ensures that only the types for which an explicit conversion has
been defined are converted). This wrapper adds an addiotional parameter
``strict`` (with default ``False``) that will raise a ``SympifyError``
if ``strict=True`` and the argument passed to the parameter ``a`` is a
string.
See Also
========
sympify: Converts an arbitrary expression to a type that can be used
inside SymPy.
"""
# The parameter ``a`` is used for this function to keep compatibility
# with the SymEngine docstring.
if strict and isinstance(a, str):
raise SympifyError(a)
return sympify_symengine(a)
# Keep the SymEngine docstring and append the additional "Notes" and "See
# Also" sections. Replacement of spaces is required to correctly format the
# indentation of the combined docstring.
sympify.__doc__ = (
sympify_symengine.__doc__
+ sympify.__doc__.replace(' ', ' ') # type: ignore
)
else:
from sympy.core.add import Add
from sympy.core.basic import Basic
from sympy.core.function import (diff, Function, AppliedUndef,
expand, Derivative)
from sympy.core.mul import Mul
from sympy.core.intfunc import igcd
from sympy.core.numbers import pi, I, Integer, Rational, E
from sympy.core.singleton import S
from sympy.core.symbol import Symbol, var, symbols
from sympy.core.sympify import SympifyError, sympify
from sympy.functions.elementary.exponential import log, exp
from sympy.functions.elementary.hyperbolic import (coth, sinh,
acosh, acoth, tanh, asinh, atanh, cosh)
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.elementary.trigonometric import (csc,
asec, cos, atan, sec, acot, asin, tan, sin, cot, acsc, acos)
from sympy.functions.special.gamma_functions import gamma
from sympy.matrices.dense import (eye, zeros, diag, Matrix,
ones, symarray)
from sympy.matrices.immutable import ImmutableMatrix
from sympy.matrices.matrixbase import MatrixBase
from sympy.utilities.lambdify import lambdify
#
# XXX: Handling of immutable and mutable matrices in SymEngine is inconsistent
# with SymPy's matrix classes in at least SymEngine version 0.7.0. Until that
# is fixed the function below is needed for consistent behaviour when
# attempting to simplify a matrix.
#
# Expected behaviour of a SymPy mutable/immutable matrix .simplify() method:
#
# Matrix.simplify() : works in place, returns None
# ImmutableMatrix.simplify() : returns a simplified copy
#
# In SymEngine both mutable and immutable matrices simplify in place and return
# None. This is inconsistent with the matrix being "immutable" and also the
# returned None leads to problems in the mechanics module.
#
# The simplify function should not be used because simplify(M) sympifies the
# matrix M and the SymEngine matrices all sympify to SymPy matrices. If we want
# to work with SymEngine matrices then we need to use their .simplify() method
# but that method does not work correctly with immutable matrices.
#
# The _simplify_matrix function can be removed when the SymEngine bug is fixed.
# Since this should be a temporary problem we do not make this function part of
# the public API.
#
# SymEngine issue: https://github.com/symengine/symengine.py/issues/363
#
def _simplify_matrix(M):
"""Return a simplified copy of the matrix M"""
if not isinstance(M, (Matrix, ImmutableMatrix)):
raise TypeError("The matrix M must be an instance of Matrix or ImmutableMatrix")
Mnew = M.as_mutable() # makes a copy if mutable
Mnew.simplify()
if isinstance(M, ImmutableMatrix):
Mnew = Mnew.as_immutable()
return Mnew
__all__ = [
'Symbol', 'Integer', 'sympify', 'S', 'SympifyError', 'exp', 'log',
'gamma', 'sqrt', 'I', 'E', 'pi', 'Matrix', 'sin', 'cos', 'tan', 'cot',
'csc', 'sec', 'asin', 'acos', 'atan', 'acot', 'acsc', 'asec', 'sinh',
'cosh', 'tanh', 'coth', 'asinh', 'acosh', 'atanh', 'acoth', 'lambdify',
'symarray', 'diff', 'zeros', 'eye', 'diag', 'ones', 'expand', 'Function',
'symbols', 'var', 'Add', 'Mul', 'Derivative', 'ImmutableMatrix',
'MatrixBase', 'Rational', 'Basic', 'igcd', 'AppliedUndef',
]
PK ]ZZZ�e�P�+ �+ sympy/core/basic.py"""Base class for all the objects in SymPy"""
from __future__ import annotations
from collections import defaultdict
from collections.abc import Mapping
from itertools import chain, zip_longest
from functools import cmp_to_key
from .assumptions import _prepare_class_assumptions
from .cache import cacheit
from .sympify import _sympify, sympify, SympifyError, _external_converter
from .sorting import ordered
from .kind import Kind, UndefinedKind
from ._print_helpers import Printable
from sympy.utilities.decorator import deprecated
from sympy.utilities.exceptions import sympy_deprecation_warning
from sympy.utilities.iterables import iterable, numbered_symbols
from sympy.utilities.misc import filldedent, func_name
from inspect import getmro
def as_Basic(expr):
"""Return expr as a Basic instance using strict sympify
or raise a TypeError; this is just a wrapper to _sympify,
raising a TypeError instead of a SympifyError."""
try:
return _sympify(expr)
except SympifyError:
raise TypeError(
'Argument must be a Basic object, not `%s`' % func_name(
expr))
# Key for sorting commutative args in canonical order
# by name. This is used for canonical ordering of the
# args for Add and Mul *if* the names of both classes
# being compared appear here. Some things in this list
# are not spelled the same as their name so they do not,
# in effect, appear here. See Basic.compare.
ordering_of_classes = [
# singleton numbers
'Zero', 'One', 'Half', 'Infinity', 'NaN', 'NegativeOne', 'NegativeInfinity',
# numbers
'Integer', 'Rational', 'Float',
# singleton symbols
'Exp1', 'Pi', 'ImaginaryUnit',
# symbols
'Symbol', 'Wild',
# arithmetic operations
'Pow', 'Mul', 'Add',
# function values
'Derivative', 'Integral',
# defined singleton functions
'Abs', 'Sign', 'Sqrt',
'Floor', 'Ceiling',
'Re', 'Im', 'Arg',
'Conjugate',
'Exp', 'Log',
'Sin', 'Cos', 'Tan', 'Cot', 'ASin', 'ACos', 'ATan', 'ACot',
'Sinh', 'Cosh', 'Tanh', 'Coth', 'ASinh', 'ACosh', 'ATanh', 'ACoth',
'RisingFactorial', 'FallingFactorial',
'factorial', 'binomial',
'Gamma', 'LowerGamma', 'UpperGamma', 'PolyGamma',
'Erf',
# special polynomials
'Chebyshev', 'Chebyshev2',
# undefined functions
'Function', 'WildFunction',
# anonymous functions
'Lambda',
# Landau O symbol
'Order',
# relational operations
'Equality', 'Unequality', 'StrictGreaterThan', 'StrictLessThan',
'GreaterThan', 'LessThan',
]
def _cmp_name(x: type, y: type) -> int:
"""return -1, 0, 1 if the name of x is before that of y.
A string comparison is done if either name does not appear
in `ordering_of_classes`. This is the helper for
``Basic.compare``
Examples
========
>>> from sympy import cos, tan, sin
>>> from sympy.core import basic
>>> save = basic.ordering_of_classes
>>> basic.ordering_of_classes = ()
>>> basic._cmp_name(cos, tan)
-1
>>> basic.ordering_of_classes = ["tan", "sin", "cos"]
>>> basic._cmp_name(cos, tan)
1
>>> basic._cmp_name(sin, cos)
-1
>>> basic.ordering_of_classes = save
"""
# If the other object is not a Basic subclass, then we are not equal to it.
if not issubclass(y, Basic):
return -1
n1 = x.__name__
n2 = y.__name__
if n1 == n2:
return 0
UNKNOWN = len(ordering_of_classes) + 1
try:
i1 = ordering_of_classes.index(n1)
except ValueError:
i1 = UNKNOWN
try:
i2 = ordering_of_classes.index(n2)
except ValueError:
i2 = UNKNOWN
if i1 == UNKNOWN and i2 == UNKNOWN:
return (n1 > n2) - (n1 < n2)
return (i1 > i2) - (i1 < i2)
class Basic(Printable):
"""
Base class for all SymPy objects.
Notes and conventions
=====================
1) Always use ``.args``, when accessing parameters of some instance:
>>> from sympy import cot
>>> from sympy.abc import x, y
>>> cot(x).args
(x,)
>>> cot(x).args[0]
x
>>> (x*y).args
(x, y)
>>> (x*y).args[1]
y
2) Never use internal methods or variables (the ones prefixed with ``_``):
>>> cot(x)._args # do not use this, use cot(x).args instead
(x,)
3) By "SymPy object" we mean something that can be returned by
``sympify``. But not all objects one encounters using SymPy are
subclasses of Basic. For example, mutable objects are not:
>>> from sympy import Basic, Matrix, sympify
>>> A = Matrix([[1, 2], [3, 4]]).as_mutable()
>>> isinstance(A, Basic)
False
>>> B = sympify(A)
>>> isinstance(B, Basic)
True
"""
__slots__ = ('_mhash', # hash value
'_args', # arguments
'_assumptions'
)
_args: tuple[Basic, ...]
_mhash: int | None
@property
def __sympy__(self):
return True
def __init_subclass__(cls):
# Initialize the default_assumptions FactKB and also any assumptions
# property methods. This method will only be called for subclasses of
# Basic but not for Basic itself so we call
# _prepare_class_assumptions(Basic) below the class definition.
super().__init_subclass__()
_prepare_class_assumptions(cls)
# To be overridden with True in the appropriate subclasses
is_number = False
is_Atom = False
is_Symbol = False
is_symbol = False
is_Indexed = False
is_Dummy = False
is_Wild = False
is_Function = False
is_Add = False
is_Mul = False
is_Pow = False
is_Number = False
is_Float = False
is_Rational = False
is_Integer = False
is_NumberSymbol = False
is_Order = False
is_Derivative = False
is_Piecewise = False
is_Poly = False
is_AlgebraicNumber = False
is_Relational = False
is_Equality = False
is_Boolean = False
is_Not = False
is_Matrix = False
is_Vector = False
is_Point = False
is_MatAdd = False
is_MatMul = False
is_real: bool | None
is_extended_real: bool | None
is_zero: bool | None
is_negative: bool | None
is_commutative: bool | None
kind: Kind = UndefinedKind
def __new__(cls, *args):
obj = object.__new__(cls)
obj._assumptions = cls.default_assumptions
obj._mhash = None # will be set by __hash__ method.
obj._args = args # all items in args must be Basic objects
return obj
def copy(self):
return self.func(*self.args)
def __getnewargs__(self):
return self.args
def __getstate__(self):
return None
def __setstate__(self, state):
for name, value in state.items():
setattr(self, name, value)
def __reduce_ex__(self, protocol):
if protocol < 2:
msg = "Only pickle protocol 2 or higher is supported by SymPy"
raise NotImplementedError(msg)
return super().__reduce_ex__(protocol)
def __hash__(self) -> int:
# hash cannot be cached using cache_it because infinite recurrence
# occurs as hash is needed for setting cache dictionary keys
h = self._mhash
if h is None:
h = hash((type(self).__name__,) + self._hashable_content())
self._mhash = h
return h
def _hashable_content(self):
"""Return a tuple of information about self that can be used to
compute the hash. If a class defines additional attributes,
like ``name`` in Symbol, then this method should be updated
accordingly to return such relevant attributes.
Defining more than _hashable_content is necessary if __eq__ has
been defined by a class. See note about this in Basic.__eq__."""
return self._args
@property
def assumptions0(self):
"""
Return object `type` assumptions.
For example:
Symbol('x', real=True)
Symbol('x', integer=True)
are different objects. In other words, besides Python type (Symbol in
this case), the initial assumptions are also forming their typeinfo.
Examples
========
>>> from sympy import Symbol
>>> from sympy.abc import x
>>> x.assumptions0
{'commutative': True}
>>> x = Symbol("x", positive=True)
>>> x.assumptions0
{'commutative': True, 'complex': True, 'extended_negative': False,
'extended_nonnegative': True, 'extended_nonpositive': False,
'extended_nonzero': True, 'extended_positive': True, 'extended_real':
True, 'finite': True, 'hermitian': True, 'imaginary': False,
'infinite': False, 'negative': False, 'nonnegative': True,
'nonpositive': False, 'nonzero': True, 'positive': True, 'real':
True, 'zero': False}
"""
return {}
def compare(self, other):
"""
Return -1, 0, 1 if the object is less than, equal,
or greater than other in a canonical sense.
Non-Basic are always greater than Basic.
If both names of the classes being compared appear
in the `ordering_of_classes` then the ordering will
depend on the appearance of the names there.
If either does not appear in that list, then the
comparison is based on the class name.
If the names are the same then a comparison is made
on the length of the hashable content.
Items of the equal-lengthed contents are then
successively compared using the same rules. If there
is never a difference then 0 is returned.
Examples
========
>>> from sympy.abc import x, y
>>> x.compare(y)
-1
>>> x.compare(x)
0
>>> y.compare(x)
1
"""
# all redefinitions of __cmp__ method should start with the
# following lines:
if self is other:
return 0
n1 = self.__class__
n2 = other.__class__
c = _cmp_name(n1, n2)
if c:
return c
#
st = self._hashable_content()
ot = other._hashable_content()
c = (len(st) > len(ot)) - (len(st) < len(ot))
if c:
return c
for l, r in zip(st, ot):
l = Basic(*l) if isinstance(l, frozenset) else l
r = Basic(*r) if isinstance(r, frozenset) else r
if isinstance(l, Basic):
c = l.compare(r)
else:
c = (l > r) - (l < r)
if c:
return c
return 0
@staticmethod
def _compare_pretty(a, b):
"""return -1, 0, 1 if a is canonically less, equal or
greater than b. This is used when 'order=old' is selected
for printing. This puts Order last, orders Rationals
according to value, puts terms in order wrt the power of
the last power appearing in a term. Ties are broken using
Basic.compare.
"""
from sympy.series.order import Order
if isinstance(a, Order) and not isinstance(b, Order):
return 1
if not isinstance(a, Order) and isinstance(b, Order):
return -1
if a.is_Rational and b.is_Rational:
l = a.p * b.q
r = b.p * a.q
return (l > r) - (l < r)
else:
from .symbol import Wild
p1, p2, p3 = Wild("p1"), Wild("p2"), Wild("p3")
r_a = a.match(p1 * p2**p3)
if r_a and p3 in r_a:
a3 = r_a[p3]
r_b = b.match(p1 * p2**p3)
if r_b and p3 in r_b:
b3 = r_b[p3]
c = Basic.compare(a3, b3)
if c != 0:
return c
# break ties
return Basic.compare(a, b)
@classmethod
def fromiter(cls, args, **assumptions):
"""
Create a new object from an iterable.
This is a convenience function that allows one to create objects from
any iterable, without having to convert to a list or tuple first.
Examples
========
>>> from sympy import Tuple
>>> Tuple.fromiter(i for i in range(5))
(0, 1, 2, 3, 4)
"""
return cls(*tuple(args), **assumptions)
@classmethod
def class_key(cls):
"""Nice order of classes."""
return 5, 0, cls.__name__
@cacheit
def sort_key(self, order=None):
"""
Return a sort key.
Examples
========
>>> from sympy import S, I
>>> sorted([S(1)/2, I, -I], key=lambda x: x.sort_key())
[1/2, -I, I]
>>> S("[x, 1/x, 1/x**2, x**2, x**(1/2), x**(1/4), x**(3/2)]")
[x, 1/x, x**(-2), x**2, sqrt(x), x**(1/4), x**(3/2)]
>>> sorted(_, key=lambda x: x.sort_key())
[x**(-2), 1/x, x**(1/4), sqrt(x), x, x**(3/2), x**2]
"""
# XXX: remove this when issue 5169 is fixed
def inner_key(arg):
if isinstance(arg, Basic):
return arg.sort_key(order)
else:
return arg
args = self._sorted_args
args = len(args), tuple([inner_key(arg) for arg in args])
return self.class_key(), args, S.One.sort_key(), S.One
def _do_eq_sympify(self, other):
"""Returns a boolean indicating whether a == b when either a
or b is not a Basic. This is only done for types that were either
added to `converter` by a 3rd party or when the object has `_sympy_`
defined. This essentially reuses the code in `_sympify` that is
specific for this use case. Non-user defined types that are meant
to work with SymPy should be handled directly in the __eq__ methods
of the `Basic` classes it could equate to and not be converted. Note
that after conversion, `==` is used again since it is not
necessarily clear whether `self` or `other`'s __eq__ method needs
to be used."""
for superclass in type(other).__mro__:
conv = _external_converter.get(superclass)
if conv is not None:
return self == conv(other)
if hasattr(other, '_sympy_'):
return self == other._sympy_()
return NotImplemented
def __eq__(self, other):
"""Return a boolean indicating whether a == b on the basis of
their symbolic trees.
This is the same as a.compare(b) == 0 but faster.
Notes
=====
If a class that overrides __eq__() needs to retain the
implementation of __hash__() from a parent class, the
interpreter must be told this explicitly by setting
__hash__ : Callable[[object], int] = <ParentClass>.__hash__.
Otherwise the inheritance of __hash__() will be blocked,
just as if __hash__ had been explicitly set to None.
References
==========
from https://docs.python.org/dev/reference/datamodel.html#object.__hash__
"""
if self is other:
return True
if not isinstance(other, Basic):
return self._do_eq_sympify(other)
# check for pure number expr
if not (self.is_Number and other.is_Number) and (
type(self) != type(other)):
return False
a, b = self._hashable_content(), other._hashable_content()
if a != b:
return False
# check number *in* an expression
for a, b in zip(a, b):
if not isinstance(a, Basic):
continue
if a.is_Number and type(a) != type(b):
return False
return True
def __ne__(self, other):
"""``a != b`` -> Compare two symbolic trees and see whether they are different
this is the same as:
``a.compare(b) != 0``
but faster
"""
return not self == other
def dummy_eq(self, other, symbol=None):
"""
Compare two expressions and handle dummy symbols.
Examples
========
>>> from sympy import Dummy
>>> from sympy.abc import x, y
>>> u = Dummy('u')
>>> (u**2 + 1).dummy_eq(x**2 + 1)
True
>>> (u**2 + 1) == (x**2 + 1)
False
>>> (u**2 + y).dummy_eq(x**2 + y, x)
True
>>> (u**2 + y).dummy_eq(x**2 + y, y)
False
"""
s = self.as_dummy()
o = _sympify(other)
o = o.as_dummy()
dummy_symbols = [i for i in s.free_symbols if i.is_Dummy]
if len(dummy_symbols) == 1:
dummy = dummy_symbols.pop()
else:
return s == o
if symbol is None:
symbols = o.free_symbols
if len(symbols) == 1:
symbol = symbols.pop()
else:
return s == o
tmp = dummy.__class__()
return s.xreplace({dummy: tmp}) == o.xreplace({symbol: tmp})
def atoms(self, *types):
"""Returns the atoms that form the current object.
By default, only objects that are truly atomic and cannot
be divided into smaller pieces are returned: symbols, numbers,
and number symbols like I and pi. It is possible to request
atoms of any type, however, as demonstrated below.
Examples
========
>>> from sympy import I, pi, sin
>>> from sympy.abc import x, y
>>> (1 + x + 2*sin(y + I*pi)).atoms()
{1, 2, I, pi, x, y}
If one or more types are given, the results will contain only
those types of atoms.
>>> from sympy import Number, NumberSymbol, Symbol
>>> (1 + x + 2*sin(y + I*pi)).atoms(Symbol)
{x, y}
>>> (1 + x + 2*sin(y + I*pi)).atoms(Number)
{1, 2}
>>> (1 + x + 2*sin(y + I*pi)).atoms(Number, NumberSymbol)
{1, 2, pi}
>>> (1 + x + 2*sin(y + I*pi)).atoms(Number, NumberSymbol, I)
{1, 2, I, pi}
Note that I (imaginary unit) and zoo (complex infinity) are special
types of number symbols and are not part of the NumberSymbol class.
The type can be given implicitly, too:
>>> (1 + x + 2*sin(y + I*pi)).atoms(x) # x is a Symbol
{x, y}
Be careful to check your assumptions when using the implicit option
since ``S(1).is_Integer = True`` but ``type(S(1))`` is ``One``, a special type
of SymPy atom, while ``type(S(2))`` is type ``Integer`` and will find all
integers in an expression:
>>> from sympy import S
>>> (1 + x + 2*sin(y + I*pi)).atoms(S(1))
{1}
>>> (1 + x + 2*sin(y + I*pi)).atoms(S(2))
{1, 2}
Finally, arguments to atoms() can select more than atomic atoms: any
SymPy type (loaded in core/__init__.py) can be listed as an argument
and those types of "atoms" as found in scanning the arguments of the
expression recursively:
>>> from sympy import Function, Mul
>>> from sympy.core.function import AppliedUndef
>>> f = Function('f')
>>> (1 + f(x) + 2*sin(y + I*pi)).atoms(Function)
{f(x), sin(y + I*pi)}
>>> (1 + f(x) + 2*sin(y + I*pi)).atoms(AppliedUndef)
{f(x)}
>>> (1 + x + 2*sin(y + I*pi)).atoms(Mul)
{I*pi, 2*sin(y + I*pi)}
"""
if types:
types = tuple(
[t if isinstance(t, type) else type(t) for t in types])
nodes = _preorder_traversal(self)
if types:
result = {node for node in nodes if isinstance(node, types)}
else:
result = {node for node in nodes if not node.args}
return result
@property
def free_symbols(self) -> set[Basic]:
"""Return from the atoms of self those which are free symbols.
Not all free symbols are ``Symbol``. Eg: IndexedBase('I')[0].free_symbols
For most expressions, all symbols are free symbols. For some classes
this is not true. e.g. Integrals use Symbols for the dummy variables
which are bound variables, so Integral has a method to return all
symbols except those. Derivative keeps track of symbols with respect
to which it will perform a derivative; those are
bound variables, too, so it has its own free_symbols method.
Any other method that uses bound variables should implement a
free_symbols method."""
empty: set[Basic] = set()
return empty.union(*(a.free_symbols for a in self.args))
@property
def expr_free_symbols(self):
sympy_deprecation_warning("""
The expr_free_symbols property is deprecated. Use free_symbols to get
the free symbols of an expression.
""",
deprecated_since_version="1.9",
active_deprecations_target="deprecated-expr-free-symbols")
return set()
def as_dummy(self):
"""Return the expression with any objects having structurally
bound symbols replaced with unique, canonical symbols within
the object in which they appear and having only the default
assumption for commutativity being True. When applied to a
symbol a new symbol having only the same commutativity will be
returned.
Examples
========
>>> from sympy import Integral, Symbol
>>> from sympy.abc import x
>>> r = Symbol('r', real=True)
>>> Integral(r, (r, x)).as_dummy()
Integral(_0, (_0, x))
>>> _.variables[0].is_real is None
True
>>> r.as_dummy()
_r
Notes
=====
Any object that has structurally bound variables should have
a property, `bound_symbols` that returns those symbols
appearing in the object.
"""
from .symbol import Dummy, Symbol
def can(x):
# mask free that shadow bound
free = x.free_symbols
bound = set(x.bound_symbols)
d = {i: Dummy() for i in bound & free}
x = x.subs(d)
# replace bound with canonical names
x = x.xreplace(x.canonical_variables)
# return after undoing masking
return x.xreplace({v: k for k, v in d.items()})
if not self.has(Symbol):
return self
return self.replace(
lambda x: hasattr(x, 'bound_symbols'),
can,
simultaneous=False)
@property
def canonical_variables(self):
"""Return a dictionary mapping any variable defined in
``self.bound_symbols`` to Symbols that do not clash
with any free symbols in the expression.
Examples
========
>>> from sympy import Lambda
>>> from sympy.abc import x
>>> Lambda(x, 2*x).canonical_variables
{x: _0}
"""
if not hasattr(self, 'bound_symbols'):
return {}
dums = numbered_symbols('_')
reps = {}
# watch out for free symbol that are not in bound symbols;
# those that are in bound symbols are about to get changed
bound = self.bound_symbols
names = {i.name for i in self.free_symbols - set(bound)}
for b in bound:
d = next(dums)
if b.is_Symbol:
while d.name in names:
d = next(dums)
reps[b] = d
return reps
def rcall(self, *args):
"""Apply on the argument recursively through the expression tree.
This method is used to simulate a common abuse of notation for
operators. For instance, in SymPy the following will not work:
``(x+Lambda(y, 2*y))(z) == x+2*z``,
however, you can use:
>>> from sympy import Lambda
>>> from sympy.abc import x, y, z
>>> (x + Lambda(y, 2*y)).rcall(z)
x + 2*z
"""
return Basic._recursive_call(self, args)
@staticmethod
def _recursive_call(expr_to_call, on_args):
"""Helper for rcall method."""
from .symbol import Symbol
def the_call_method_is_overridden(expr):
for cls in getmro(type(expr)):
if '__call__' in cls.__dict__:
return cls != Basic
if callable(expr_to_call) and the_call_method_is_overridden(expr_to_call):
if isinstance(expr_to_call, Symbol): # XXX When you call a Symbol it is
return expr_to_call # transformed into an UndefFunction
else:
return expr_to_call(*on_args)
elif expr_to_call.args:
args = [Basic._recursive_call(
sub, on_args) for sub in expr_to_call.args]
return type(expr_to_call)(*args)
else:
return expr_to_call
def is_hypergeometric(self, k):
from sympy.simplify.simplify import hypersimp
from sympy.functions.elementary.piecewise import Piecewise
if self.has(Piecewise):
return None
return hypersimp(self, k) is not None
@property
def is_comparable(self):
"""Return True if self can be computed to a real number
(or already is a real number) with precision, else False.
Examples
========
>>> from sympy import exp_polar, pi, I
>>> (I*exp_polar(I*pi/2)).is_comparable
True
>>> (I*exp_polar(I*pi*2)).is_comparable
False
A False result does not mean that `self` cannot be rewritten
into a form that would be comparable. For example, the
difference computed below is zero but without simplification
it does not evaluate to a zero with precision:
>>> e = 2**pi*(1 + 2**pi)
>>> dif = e - e.expand()
>>> dif.is_comparable
False
>>> dif.n(2)._prec
1
"""
is_extended_real = self.is_extended_real
if is_extended_real is False:
return False
if not self.is_number:
return False
# don't re-eval numbers that are already evaluated since
# this will create spurious precision
n, i = [p.evalf(2) if not p.is_Number else p
for p in self.as_real_imag()]
if not (i.is_Number and n.is_Number):
return False
if i:
# if _prec = 1 we can't decide and if not,
# the answer is False because numbers with
# imaginary parts can't be compared
# so return False
return False
else:
return n._prec != 1
@property
def func(self):
"""
The top-level function in an expression.
The following should hold for all objects::
>> x == x.func(*x.args)
Examples
========
>>> from sympy.abc import x
>>> a = 2*x
>>> a.func
<class 'sympy.core.mul.Mul'>
>>> a.args
(2, x)
>>> a.func(*a.args)
2*x
>>> a == a.func(*a.args)
True
"""
return self.__class__
@property
def args(self) -> tuple[Basic, ...]:
"""Returns a tuple of arguments of 'self'.
Examples
========
>>> from sympy import cot
>>> from sympy.abc import x, y
>>> cot(x).args
(x,)
>>> cot(x).args[0]
x
>>> (x*y).args
(x, y)
>>> (x*y).args[1]
y
Notes
=====
Never use self._args, always use self.args.
Only use _args in __new__ when creating a new function.
Do not override .args() from Basic (so that it is easy to
change the interface in the future if needed).
"""
return self._args
@property
def _sorted_args(self):
"""
The same as ``args``. Derived classes which do not fix an
order on their arguments should override this method to
produce the sorted representation.
"""
return self.args
def as_content_primitive(self, radical=False, clear=True):
"""A stub to allow Basic args (like Tuple) to be skipped when computing
the content and primitive components of an expression.
See Also
========
sympy.core.expr.Expr.as_content_primitive
"""
return S.One, self
def subs(self, *args, **kwargs):
"""
Substitutes old for new in an expression after sympifying args.
`args` is either:
- two arguments, e.g. foo.subs(old, new)
- one iterable argument, e.g. foo.subs(iterable). The iterable may be
o an iterable container with (old, new) pairs. In this case the
replacements are processed in the order given with successive
patterns possibly affecting replacements already made.
o a dict or set whose key/value items correspond to old/new pairs.
In this case the old/new pairs will be sorted by op count and in
case of a tie, by number of args and the default_sort_key. The
resulting sorted list is then processed as an iterable container
(see previous).
If the keyword ``simultaneous`` is True, the subexpressions will not be
evaluated until all the substitutions have been made.
Examples
========
>>> from sympy import pi, exp, limit, oo
>>> from sympy.abc import x, y
>>> (1 + x*y).subs(x, pi)
pi*y + 1
>>> (1 + x*y).subs({x:pi, y:2})
1 + 2*pi
>>> (1 + x*y).subs([(x, pi), (y, 2)])
1 + 2*pi
>>> reps = [(y, x**2), (x, 2)]
>>> (x + y).subs(reps)
6
>>> (x + y).subs(reversed(reps))
x**2 + 2
>>> (x**2 + x**4).subs(x**2, y)
y**2 + y
To replace only the x**2 but not the x**4, use xreplace:
>>> (x**2 + x**4).xreplace({x**2: y})
x**4 + y
To delay evaluation until all substitutions have been made,
set the keyword ``simultaneous`` to True:
>>> (x/y).subs([(x, 0), (y, 0)])
0
>>> (x/y).subs([(x, 0), (y, 0)], simultaneous=True)
nan
This has the added feature of not allowing subsequent substitutions
to affect those already made:
>>> ((x + y)/y).subs({x + y: y, y: x + y})
1
>>> ((x + y)/y).subs({x + y: y, y: x + y}, simultaneous=True)
y/(x + y)
In order to obtain a canonical result, unordered iterables are
sorted by count_op length, number of arguments and by the
default_sort_key to break any ties. All other iterables are left
unsorted.
>>> from sympy import sqrt, sin, cos
>>> from sympy.abc import a, b, c, d, e
>>> A = (sqrt(sin(2*x)), a)
>>> B = (sin(2*x), b)
>>> C = (cos(2*x), c)
>>> D = (x, d)
>>> E = (exp(x), e)
>>> expr = sqrt(sin(2*x))*sin(exp(x)*x)*cos(2*x) + sin(2*x)
>>> expr.subs(dict([A, B, C, D, E]))
a*c*sin(d*e) + b
The resulting expression represents a literal replacement of the
old arguments with the new arguments. This may not reflect the
limiting behavior of the expression:
>>> (x**3 - 3*x).subs({x: oo})
nan
>>> limit(x**3 - 3*x, x, oo)
oo
If the substitution will be followed by numerical
evaluation, it is better to pass the substitution to
evalf as
>>> (1/x).evalf(subs={x: 3.0}, n=21)
0.333333333333333333333
rather than
>>> (1/x).subs({x: 3.0}).evalf(21)
0.333333333333333314830
as the former will ensure that the desired level of precision is
obtained.
See Also
========
replace: replacement capable of doing wildcard-like matching,
parsing of match, and conditional replacements
xreplace: exact node replacement in expr tree; also capable of
using matching rules
sympy.core.evalf.EvalfMixin.evalf: calculates the given formula to a desired level of precision
"""
from .containers import Dict
from .symbol import Dummy, Symbol
from .numbers import _illegal
unordered = False
if len(args) == 1:
sequence = args[0]
if isinstance(sequence, set):
unordered = True
elif isinstance(sequence, (Dict, Mapping)):
unordered = True
sequence = sequence.items()
elif not iterable(sequence):
raise ValueError(filldedent("""
When a single argument is passed to subs
it should be a dictionary of old: new pairs or an iterable
of (old, new) tuples."""))
elif len(args) == 2:
sequence = [args]
else:
raise ValueError("subs accepts either 1 or 2 arguments")
def sympify_old(old):
if isinstance(old, str):
# Use Symbol rather than parse_expr for old
return Symbol(old)
elif isinstance(old, type):
# Allow a type e.g. Function('f') or sin
return sympify(old, strict=False)
else:
return sympify(old, strict=True)
def sympify_new(new):
if isinstance(new, (str, type)):
# Allow a type or parse a string input
return sympify(new, strict=False)
else:
return sympify(new, strict=True)
sequence = [(sympify_old(s1), sympify_new(s2)) for s1, s2 in sequence]
# skip if there is no change
sequence = [(s1, s2) for s1, s2 in sequence if not _aresame(s1, s2)]
simultaneous = kwargs.pop('simultaneous', False)
if unordered:
from .sorting import _nodes, default_sort_key
sequence = dict(sequence)
# order so more complex items are first and items
# of identical complexity are ordered so
# f(x) < f(y) < x < y
# \___ 2 __/ \_1_/ <- number of nodes
#
# For more complex ordering use an unordered sequence.
k = list(ordered(sequence, default=False, keys=(
lambda x: -_nodes(x),
default_sort_key,
)))
sequence = [(k, sequence[k]) for k in k]
# do infinities first
if not simultaneous:
redo = [i for i, seq in enumerate(sequence) if seq[1] in _illegal]
for i in reversed(redo):
sequence.insert(0, sequence.pop(i))
if simultaneous: # XXX should this be the default for dict subs?
reps = {}
rv = self
kwargs['hack2'] = True
m = Dummy('subs_m')
for old, new in sequence:
com = new.is_commutative
if com is None:
com = True
d = Dummy('subs_d', commutative=com)
# using d*m so Subs will be used on dummy variables
# in things like Derivative(f(x, y), x) in which x
# is both free and bound
rv = rv._subs(old, d*m, **kwargs)
if not isinstance(rv, Basic):
break
reps[d] = new
reps[m] = S.One # get rid of m
return rv.xreplace(reps)
else:
rv = self
for old, new in sequence:
rv = rv._subs(old, new, **kwargs)
if not isinstance(rv, Basic):
break
return rv
@cacheit
def _subs(self, old, new, **hints):
"""Substitutes an expression old -> new.
If self is not equal to old then _eval_subs is called.
If _eval_subs does not want to make any special replacement
then a None is received which indicates that the fallback
should be applied wherein a search for replacements is made
amongst the arguments of self.
>>> from sympy import Add
>>> from sympy.abc import x, y, z
Examples
========
Add's _eval_subs knows how to target x + y in the following
so it makes the change:
>>> (x + y + z).subs(x + y, 1)
z + 1
Add's _eval_subs does not need to know how to find x + y in
the following:
>>> Add._eval_subs(z*(x + y) + 3, x + y, 1) is None
True
The returned None will cause the fallback routine to traverse the args and
pass the z*(x + y) arg to Mul where the change will take place and the
substitution will succeed:
>>> (z*(x + y) + 3).subs(x + y, 1)
z + 3
** Developers Notes **
An _eval_subs routine for a class should be written if:
1) any arguments are not instances of Basic (e.g. bool, tuple);
2) some arguments should not be targeted (as in integration
variables);
3) if there is something other than a literal replacement
that should be attempted (as in Piecewise where the condition
may be updated without doing a replacement).
If it is overridden, here are some special cases that might arise:
1) If it turns out that no special change was made and all
the original sub-arguments should be checked for
replacements then None should be returned.
2) If it is necessary to do substitutions on a portion of
the expression then _subs should be called. _subs will
handle the case of any sub-expression being equal to old
(which usually would not be the case) while its fallback
will handle the recursion into the sub-arguments. For
example, after Add's _eval_subs removes some matching terms
it must process the remaining terms so it calls _subs
on each of the un-matched terms and then adds them
onto the terms previously obtained.
3) If the initial expression should remain unchanged then
the original expression should be returned. (Whenever an
expression is returned, modified or not, no further
substitution of old -> new is attempted.) Sum's _eval_subs
routine uses this strategy when a substitution is attempted
on any of its summation variables.
"""
def fallback(self, old, new):
"""
Try to replace old with new in any of self's arguments.
"""
hit = False
args = list(self.args)
for i, arg in enumerate(args):
if not hasattr(arg, '_eval_subs'):
continue
arg = arg._subs(old, new, **hints)
if not _aresame(arg, args[i]):
hit = True
args[i] = arg
if hit:
rv = self.func(*args)
hack2 = hints.get('hack2', False)
if hack2 and self.is_Mul and not rv.is_Mul: # 2-arg hack
coeff = S.One
nonnumber = []
for i in args:
if i.is_Number:
coeff *= i
else:
nonnumber.append(i)
nonnumber = self.func(*nonnumber)
if coeff is S.One:
return nonnumber
else:
return self.func(coeff, nonnumber, evaluate=False)
return rv
return self
if _aresame(self, old):
return new
rv = self._eval_subs(old, new)
if rv is None:
rv = fallback(self, old, new)
return rv
def _eval_subs(self, old, new):
"""Override this stub if you want to do anything more than
attempt a replacement of old with new in the arguments of self.
See also
========
_subs
"""
return None
def xreplace(self, rule):
"""
Replace occurrences of objects within the expression.
Parameters
==========
rule : dict-like
Expresses a replacement rule
Returns
=======
xreplace : the result of the replacement
Examples
========
>>> from sympy import symbols, pi, exp
>>> x, y, z = symbols('x y z')
>>> (1 + x*y).xreplace({x: pi})
pi*y + 1
>>> (1 + x*y).xreplace({x: pi, y: 2})
1 + 2*pi
Replacements occur only if an entire node in the expression tree is
matched:
>>> (x*y + z).xreplace({x*y: pi})
z + pi
>>> (x*y*z).xreplace({x*y: pi})
x*y*z
>>> (2*x).xreplace({2*x: y, x: z})
y
>>> (2*2*x).xreplace({2*x: y, x: z})
4*z
>>> (x + y + 2).xreplace({x + y: 2})
x + y + 2
>>> (x + 2 + exp(x + 2)).xreplace({x + 2: y})
x + exp(y) + 2
xreplace does not differentiate between free and bound symbols. In the
following, subs(x, y) would not change x since it is a bound symbol,
but xreplace does:
>>> from sympy import Integral
>>> Integral(x, (x, 1, 2*x)).xreplace({x: y})
Integral(y, (y, 1, 2*y))
Trying to replace x with an expression raises an error:
>>> Integral(x, (x, 1, 2*x)).xreplace({x: 2*y}) # doctest: +SKIP
ValueError: Invalid limits given: ((2*y, 1, 4*y),)
See Also
========
replace: replacement capable of doing wildcard-like matching,
parsing of match, and conditional replacements
subs: substitution of subexpressions as defined by the objects
themselves.
"""
value, _ = self._xreplace(rule)
return value
def _xreplace(self, rule):
"""
Helper for xreplace. Tracks whether a replacement actually occurred.
"""
if self in rule:
return rule[self], True
elif rule:
args = []
changed = False
for a in self.args:
_xreplace = getattr(a, '_xreplace', None)
if _xreplace is not None:
a_xr = _xreplace(rule)
args.append(a_xr[0])
changed |= a_xr[1]
else:
args.append(a)
args = tuple(args)
if changed:
return self.func(*args), True
return self, False
@cacheit
def has(self, *patterns):
"""
Test whether any subexpression matches any of the patterns.
Examples
========
>>> from sympy import sin
>>> from sympy.abc import x, y, z
>>> (x**2 + sin(x*y)).has(z)
False
>>> (x**2 + sin(x*y)).has(x, y, z)
True
>>> x.has(x)
True
Note ``has`` is a structural algorithm with no knowledge of
mathematics. Consider the following half-open interval:
>>> from sympy import Interval
>>> i = Interval.Lopen(0, 5); i
Interval.Lopen(0, 5)
>>> i.args
(0, 5, True, False)
>>> i.has(4) # there is no "4" in the arguments
False
>>> i.has(0) # there *is* a "0" in the arguments
True
Instead, use ``contains`` to determine whether a number is in the
interval or not:
>>> i.contains(4)
True
>>> i.contains(0)
False
Note that ``expr.has(*patterns)`` is exactly equivalent to
``any(expr.has(p) for p in patterns)``. In particular, ``False`` is
returned when the list of patterns is empty.
>>> x.has()
False
"""
return self._has(iterargs, *patterns)
def has_xfree(self, s: set[Basic]):
"""Return True if self has any of the patterns in s as a
free argument, else False. This is like `Basic.has_free`
but this will only report exact argument matches.
Examples
========
>>> from sympy import Function
>>> from sympy.abc import x, y
>>> f = Function('f')
>>> f(x).has_xfree({f})
False
>>> f(x).has_xfree({f(x)})
True
>>> f(x + 1).has_xfree({x})
True
>>> f(x + 1).has_xfree({x + 1})
True
>>> f(x + y + 1).has_xfree({x + 1})
False
"""
# protect O(1) containment check by requiring:
if type(s) is not set:
raise TypeError('expecting set argument')
return any(a in s for a in iterfreeargs(self))
@cacheit
def has_free(self, *patterns):
"""Return True if self has object(s) ``x`` as a free expression
else False.
Examples
========
>>> from sympy import Integral, Function
>>> from sympy.abc import x, y
>>> f = Function('f')
>>> g = Function('g')
>>> expr = Integral(f(x), (f(x), 1, g(y)))
>>> expr.free_symbols
{y}
>>> expr.has_free(g(y))
True
>>> expr.has_free(*(x, f(x)))
False
This works for subexpressions and types, too:
>>> expr.has_free(g)
True
>>> (x + y + 1).has_free(y + 1)
True
"""
if not patterns:
return False
p0 = patterns[0]
if len(patterns) == 1 and iterable(p0) and not isinstance(p0, Basic):
# Basic can contain iterables (though not non-Basic, ideally)
# but don't encourage mixed passing patterns
raise TypeError(filldedent('''
Expecting 1 or more Basic args, not a single
non-Basic iterable. Don't forget to unpack
iterables: `eq.has_free(*patterns)`'''))
# try quick test first
s = set(patterns)
rv = self.has_xfree(s)
if rv:
return rv
# now try matching through slower _has
return self._has(iterfreeargs, *patterns)
def _has(self, iterargs, *patterns):
# separate out types and unhashable objects
type_set = set() # only types
p_set = set() # hashable non-types
for p in patterns:
if isinstance(p, type) and issubclass(p, Basic):
type_set.add(p)
continue
if not isinstance(p, Basic):
try:
p = _sympify(p)
except SympifyError:
continue # Basic won't have this in it
p_set.add(p) # fails if object defines __eq__ but
# doesn't define __hash__
types = tuple(type_set) #
for i in iterargs(self): #
if i in p_set: # <--- here, too
return True
if isinstance(i, types):
return True
# use matcher if defined, e.g. operations defines
# matcher that checks for exact subset containment,
# (x + y + 1).has(x + 1) -> True
for i in p_set - type_set: # types don't have matchers
if not hasattr(i, '_has_matcher'):
continue
match = i._has_matcher()
if any(match(arg) for arg in iterargs(self)):
return True
# no success
return False
def replace(self, query, value, map=False, simultaneous=True, exact=None):
"""
Replace matching subexpressions of ``self`` with ``value``.
If ``map = True`` then also return the mapping {old: new} where ``old``
was a sub-expression found with query and ``new`` is the replacement
value for it. If the expression itself does not match the query, then
the returned value will be ``self.xreplace(map)`` otherwise it should
be ``self.subs(ordered(map.items()))``.
Traverses an expression tree and performs replacement of matching
subexpressions from the bottom to the top of the tree. The default
approach is to do the replacement in a simultaneous fashion so
changes made are targeted only once. If this is not desired or causes
problems, ``simultaneous`` can be set to False.
In addition, if an expression containing more than one Wild symbol
is being used to match subexpressions and the ``exact`` flag is None
it will be set to True so the match will only succeed if all non-zero
values are received for each Wild that appears in the match pattern.
Setting this to False accepts a match of 0; while setting it True
accepts all matches that have a 0 in them. See example below for
cautions.
The list of possible combinations of queries and replacement values
is listed below:
Examples
========
Initial setup
>>> from sympy import log, sin, cos, tan, Wild, Mul, Add
>>> from sympy.abc import x, y
>>> f = log(sin(x)) + tan(sin(x**2))
1.1. type -> type
obj.replace(type, newtype)
When object of type ``type`` is found, replace it with the
result of passing its argument(s) to ``newtype``.
>>> f.replace(sin, cos)
log(cos(x)) + tan(cos(x**2))
>>> sin(x).replace(sin, cos, map=True)
(cos(x), {sin(x): cos(x)})
>>> (x*y).replace(Mul, Add)
x + y
1.2. type -> func
obj.replace(type, func)
When object of type ``type`` is found, apply ``func`` to its
argument(s). ``func`` must be written to handle the number
of arguments of ``type``.
>>> f.replace(sin, lambda arg: sin(2*arg))
log(sin(2*x)) + tan(sin(2*x**2))
>>> (x*y).replace(Mul, lambda *args: sin(2*Mul(*args)))
sin(2*x*y)
2.1. pattern -> expr
obj.replace(pattern(wild), expr(wild))
Replace subexpressions matching ``pattern`` with the expression
written in terms of the Wild symbols in ``pattern``.
>>> a, b = map(Wild, 'ab')
>>> f.replace(sin(a), tan(a))
log(tan(x)) + tan(tan(x**2))
>>> f.replace(sin(a), tan(a/2))
log(tan(x/2)) + tan(tan(x**2/2))
>>> f.replace(sin(a), a)
log(x) + tan(x**2)
>>> (x*y).replace(a*x, a)
y
Matching is exact by default when more than one Wild symbol
is used: matching fails unless the match gives non-zero
values for all Wild symbols:
>>> (2*x + y).replace(a*x + b, b - a)
y - 2
>>> (2*x).replace(a*x + b, b - a)
2*x
When set to False, the results may be non-intuitive:
>>> (2*x).replace(a*x + b, b - a, exact=False)
2/x
2.2. pattern -> func
obj.replace(pattern(wild), lambda wild: expr(wild))
All behavior is the same as in 2.1 but now a function in terms of
pattern variables is used rather than an expression:
>>> f.replace(sin(a), lambda a: sin(2*a))
log(sin(2*x)) + tan(sin(2*x**2))
3.1. func -> func
obj.replace(filter, func)
Replace subexpression ``e`` with ``func(e)`` if ``filter(e)``
is True.
>>> g = 2*sin(x**3)
>>> g.replace(lambda expr: expr.is_Number, lambda expr: expr**2)
4*sin(x**9)
The expression itself is also targeted by the query but is done in
such a fashion that changes are not made twice.
>>> e = x*(x*y + 1)
>>> e.replace(lambda x: x.is_Mul, lambda x: 2*x)
2*x*(2*x*y + 1)
When matching a single symbol, `exact` will default to True, but
this may or may not be the behavior that is desired:
Here, we want `exact=False`:
>>> from sympy import Function
>>> f = Function('f')
>>> e = f(1) + f(0)
>>> q = f(a), lambda a: f(a + 1)
>>> e.replace(*q, exact=False)
f(1) + f(2)
>>> e.replace(*q, exact=True)
f(0) + f(2)
But here, the nature of matching makes selecting
the right setting tricky:
>>> e = x**(1 + y)
>>> (x**(1 + y)).replace(x**(1 + a), lambda a: x**-a, exact=False)
x
>>> (x**(1 + y)).replace(x**(1 + a), lambda a: x**-a, exact=True)
x**(-x - y + 1)
>>> (x**y).replace(x**(1 + a), lambda a: x**-a, exact=False)
x
>>> (x**y).replace(x**(1 + a), lambda a: x**-a, exact=True)
x**(1 - y)
It is probably better to use a different form of the query
that describes the target expression more precisely:
>>> (1 + x**(1 + y)).replace(
... lambda x: x.is_Pow and x.exp.is_Add and x.exp.args[0] == 1,
... lambda x: x.base**(1 - (x.exp - 1)))
...
x**(1 - y) + 1
See Also
========
subs: substitution of subexpressions as defined by the objects
themselves.
xreplace: exact node replacement in expr tree; also capable of
using matching rules
"""
try:
query = _sympify(query)
except SympifyError:
pass
try:
value = _sympify(value)
except SympifyError:
pass
if isinstance(query, type):
_query = lambda expr: isinstance(expr, query)
if isinstance(value, type):
_value = lambda expr, result: value(*expr.args)
elif callable(value):
_value = lambda expr, result: value(*expr.args)
else:
raise TypeError(
"given a type, replace() expects another "
"type or a callable")
elif isinstance(query, Basic):
_query = lambda expr: expr.match(query)
if exact is None:
from .symbol import Wild
exact = (len(query.atoms(Wild)) > 1)
if isinstance(value, Basic):
if exact:
_value = lambda expr, result: (value.subs(result)
if all(result.values()) else expr)
else:
_value = lambda expr, result: value.subs(result)
elif callable(value):
# match dictionary keys get the trailing underscore stripped
# from them and are then passed as keywords to the callable;
# if ``exact`` is True, only accept match if there are no null
# values amongst those matched.
if exact:
_value = lambda expr, result: (value(**
{str(k)[:-1]: v for k, v in result.items()})
if all(val for val in result.values()) else expr)
else:
_value = lambda expr, result: value(**
{str(k)[:-1]: v for k, v in result.items()})
else:
raise TypeError(
"given an expression, replace() expects "
"another expression or a callable")
elif callable(query):
_query = query
if callable(value):
_value = lambda expr, result: value(expr)
else:
raise TypeError(
"given a callable, replace() expects "
"another callable")
else:
raise TypeError(
"first argument to replace() must be a "
"type, an expression or a callable")
def walk(rv, F):
"""Apply ``F`` to args and then to result.
"""
args = getattr(rv, 'args', None)
if args is not None:
if args:
newargs = tuple([walk(a, F) for a in args])
if args != newargs:
rv = rv.func(*newargs)
if simultaneous:
# if rv is something that was already
# matched (that was changed) then skip
# applying F again
for i, e in enumerate(args):
if rv == e and e != newargs[i]:
return rv
rv = F(rv)
return rv
mapping = {} # changes that took place
def rec_replace(expr):
result = _query(expr)
if result or result == {}:
v = _value(expr, result)
if v is not None and v != expr:
if map:
mapping[expr] = v
expr = v
return expr
rv = walk(self, rec_replace)
return (rv, mapping) if map else rv
def find(self, query, group=False):
"""Find all subexpressions matching a query."""
query = _make_find_query(query)
results = list(filter(query, _preorder_traversal(self)))
if not group:
return set(results)
else:
groups = {}
for result in results:
if result in groups:
groups[result] += 1
else:
groups[result] = 1
return groups
def count(self, query):
"""Count the number of matching subexpressions."""
query = _make_find_query(query)
return sum(bool(query(sub)) for sub in _preorder_traversal(self))
def matches(self, expr, repl_dict=None, old=False):
"""
Helper method for match() that looks for a match between Wild symbols
in self and expressions in expr.
Examples
========
>>> from sympy import symbols, Wild, Basic
>>> a, b, c = symbols('a b c')
>>> x = Wild('x')
>>> Basic(a + x, x).matches(Basic(a + b, c)) is None
True
>>> Basic(a + x, x).matches(Basic(a + b + c, b + c))
{x_: b + c}
"""
expr = sympify(expr)
if not isinstance(expr, self.__class__):
return None
if repl_dict is None:
repl_dict = {}
else:
repl_dict = repl_dict.copy()
if self == expr:
return repl_dict
if len(self.args) != len(expr.args):
return None
d = repl_dict # already a copy
for arg, other_arg in zip(self.args, expr.args):
if arg == other_arg:
continue
if arg.is_Relational:
try:
d = arg.xreplace(d).matches(other_arg, d, old=old)
except TypeError: # Should be InvalidComparisonError when introduced
d = None
else:
d = arg.xreplace(d).matches(other_arg, d, old=old)
if d is None:
return None
return d
def match(self, pattern, old=False):
"""
Pattern matching.
Wild symbols match all.
Return ``None`` when expression (self) does not match
with pattern. Otherwise return a dictionary such that::
pattern.xreplace(self.match(pattern)) == self
Examples
========
>>> from sympy import Wild, Sum
>>> from sympy.abc import x, y
>>> p = Wild("p")
>>> q = Wild("q")
>>> r = Wild("r")
>>> e = (x+y)**(x+y)
>>> e.match(p**p)
{p_: x + y}
>>> e.match(p**q)
{p_: x + y, q_: x + y}
>>> e = (2*x)**2
>>> e.match(p*q**r)
{p_: 4, q_: x, r_: 2}
>>> (p*q**r).xreplace(e.match(p*q**r))
4*x**2
Structurally bound symbols are ignored during matching:
>>> Sum(x, (x, 1, 2)).match(Sum(y, (y, 1, p)))
{p_: 2}
But they can be identified if desired:
>>> Sum(x, (x, 1, 2)).match(Sum(q, (q, 1, p)))
{p_: 2, q_: x}
The ``old`` flag will give the old-style pattern matching where
expressions and patterns are essentially solved to give the
match. Both of the following give None unless ``old=True``:
>>> (x - 2).match(p - x, old=True)
{p_: 2*x - 2}
>>> (2/x).match(p*x, old=True)
{p_: 2/x**2}
"""
pattern = sympify(pattern)
# match non-bound symbols
canonical = lambda x: x if x.is_Symbol else x.as_dummy()
m = canonical(pattern).matches(canonical(self), old=old)
if m is None:
return m
from .symbol import Wild
from .function import WildFunction
from ..tensor.tensor import WildTensor, WildTensorIndex, WildTensorHead
wild = pattern.atoms(Wild, WildFunction, WildTensor, WildTensorIndex, WildTensorHead)
# sanity check
if set(m) - wild:
raise ValueError(filldedent('''
Some `matches` routine did not use a copy of repl_dict
and injected unexpected symbols. Report this as an
error at https://github.com/sympy/sympy/issues'''))
# now see if bound symbols were requested
bwild = wild - set(m)
if not bwild:
return m
# replace free-Wild symbols in pattern with match result
# so they will match but not be in the next match
wpat = pattern.xreplace(m)
# identify remaining bound wild
w = wpat.matches(self, old=old)
# add them to m
if w:
m.update(w)
# done
return m
def count_ops(self, visual=None):
"""Wrapper for count_ops that returns the operation count."""
from .function import count_ops
return count_ops(self, visual)
def doit(self, **hints):
"""Evaluate objects that are not evaluated by default like limits,
integrals, sums and products. All objects of this kind will be
evaluated recursively, unless some species were excluded via 'hints'
or unless the 'deep' hint was set to 'False'.
>>> from sympy import Integral
>>> from sympy.abc import x
>>> 2*Integral(x, x)
2*Integral(x, x)
>>> (2*Integral(x, x)).doit()
x**2
>>> (2*Integral(x, x)).doit(deep=False)
2*Integral(x, x)
"""
if hints.get('deep', True):
terms = [term.doit(**hints) if isinstance(term, Basic) else term
for term in self.args]
return self.func(*terms)
else:
return self
def simplify(self, **kwargs):
"""See the simplify function in sympy.simplify"""
from sympy.simplify.simplify import simplify
return simplify(self, **kwargs)
def refine(self, assumption=True):
"""See the refine function in sympy.assumptions"""
from sympy.assumptions.refine import refine
return refine(self, assumption)
def _eval_derivative_n_times(self, s, n):
# This is the default evaluator for derivatives (as called by `diff`
# and `Derivative`), it will attempt a loop to derive the expression
# `n` times by calling the corresponding `_eval_derivative` method,
# while leaving the derivative unevaluated if `n` is symbolic. This
# method should be overridden if the object has a closed form for its
# symbolic n-th derivative.
from .numbers import Integer
if isinstance(n, (int, Integer)):
obj = self
for i in range(n):
obj2 = obj._eval_derivative(s)
if obj == obj2 or obj2 is None:
break
obj = obj2
return obj2
else:
return None
def rewrite(self, *args, deep=True, **hints):
"""
Rewrite *self* using a defined rule.
Rewriting transforms an expression to another, which is mathematically
equivalent but structurally different. For example you can rewrite
trigonometric functions as complex exponentials or combinatorial
functions as gamma function.
This method takes a *pattern* and a *rule* as positional arguments.
*pattern* is optional parameter which defines the types of expressions
that will be transformed. If it is not passed, all possible expressions
will be rewritten. *rule* defines how the expression will be rewritten.
Parameters
==========
args : Expr
A *rule*, or *pattern* and *rule*.
- *pattern* is a type or an iterable of types.
- *rule* can be any object.
deep : bool, optional
If ``True``, subexpressions are recursively transformed. Default is
``True``.
Examples
========
If *pattern* is unspecified, all possible expressions are transformed.
>>> from sympy import cos, sin, exp, I
>>> from sympy.abc import x
>>> expr = cos(x) + I*sin(x)
>>> expr.rewrite(exp)
exp(I*x)
Pattern can be a type or an iterable of types.
>>> expr.rewrite(sin, exp)
exp(I*x)/2 + cos(x) - exp(-I*x)/2
>>> expr.rewrite([cos,], exp)
exp(I*x)/2 + I*sin(x) + exp(-I*x)/2
>>> expr.rewrite([cos, sin], exp)
exp(I*x)
Rewriting behavior can be implemented by defining ``_eval_rewrite()``
method.
>>> from sympy import Expr, sqrt, pi
>>> class MySin(Expr):
... def _eval_rewrite(self, rule, args, **hints):
... x, = args
... if rule == cos:
... return cos(pi/2 - x, evaluate=False)
... if rule == sqrt:
... return sqrt(1 - cos(x)**2)
>>> MySin(MySin(x)).rewrite(cos)
cos(-cos(-x + pi/2) + pi/2)
>>> MySin(x).rewrite(sqrt)
sqrt(1 - cos(x)**2)
Defining ``_eval_rewrite_as_[...]()`` method is supported for backwards
compatibility reason. This may be removed in the future and using it is
discouraged.
>>> class MySin(Expr):
... def _eval_rewrite_as_cos(self, *args, **hints):
... x, = args
... return cos(pi/2 - x, evaluate=False)
>>> MySin(x).rewrite(cos)
cos(-x + pi/2)
"""
if not args:
return self
hints.update(deep=deep)
pattern = args[:-1]
rule = args[-1]
# support old design by _eval_rewrite_as_[...] method
if isinstance(rule, str):
method = "_eval_rewrite_as_%s" % rule
elif hasattr(rule, "__name__"):
# rule is class or function
clsname = rule.__name__
method = "_eval_rewrite_as_%s" % clsname
else:
# rule is instance
clsname = rule.__class__.__name__
method = "_eval_rewrite_as_%s" % clsname
if pattern:
if iterable(pattern[0]):
pattern = pattern[0]
pattern = tuple(p for p in pattern if self.has(p))
if not pattern:
return self
# hereafter, empty pattern is interpreted as all pattern.
return self._rewrite(pattern, rule, method, **hints)
def _rewrite(self, pattern, rule, method, **hints):
deep = hints.pop('deep', True)
if deep:
args = [a._rewrite(pattern, rule, method, **hints)
for a in self.args]
else:
args = self.args
if not pattern or any(isinstance(self, p) for p in pattern):
meth = getattr(self, method, None)
if meth is not None:
rewritten = meth(*args, **hints)
else:
rewritten = self._eval_rewrite(rule, args, **hints)
if rewritten is not None:
return rewritten
if not args:
return self
return self.func(*args)
def _eval_rewrite(self, rule, args, **hints):
return None
_constructor_postprocessor_mapping = {} # type: ignore
@classmethod
def _exec_constructor_postprocessors(cls, obj):
# WARNING: This API is experimental.
# This is an experimental API that introduces constructor
# postprosessors for SymPy Core elements. If an argument of a SymPy
# expression has a `_constructor_postprocessor_mapping` attribute, it will
# be interpreted as a dictionary containing lists of postprocessing
# functions for matching expression node names.
clsname = obj.__class__.__name__
postprocessors = defaultdict(list)
for i in obj.args:
try:
postprocessor_mappings = (
Basic._constructor_postprocessor_mapping[cls].items()
for cls in type(i).mro()
if cls in Basic._constructor_postprocessor_mapping
)
for k, v in chain.from_iterable(postprocessor_mappings):
postprocessors[k].extend([j for j in v if j not in postprocessors[k]])
except TypeError:
pass
for f in postprocessors.get(clsname, []):
obj = f(obj)
return obj
def _sage_(self):
"""
Convert *self* to a symbolic expression of SageMath.
This version of the method is merely a placeholder.
"""
old_method = self._sage_
from sage.interfaces.sympy import sympy_init
sympy_init() # may monkey-patch _sage_ method into self's class or superclasses
if old_method == self._sage_:
raise NotImplementedError('conversion to SageMath is not implemented')
else:
# call the freshly monkey-patched method
return self._sage_()
def could_extract_minus_sign(self):
return False # see Expr.could_extract_minus_sign
def is_same(a, b, approx=None):
"""Return True if a and b are structurally the same, else False.
If `approx` is supplied, it will be used to test whether two
numbers are the same or not. By default, only numbers of the
same type will compare equal, so S.Half != Float(0.5).
Examples
========
In SymPy (unlike Python) two numbers do not compare the same if they are
not of the same type:
>>> from sympy import S
>>> 2.0 == S(2)
False
>>> 0.5 == S.Half
False
By supplying a function with which to compare two numbers, such
differences can be ignored. e.g. `equal_valued` will return True
for decimal numbers having a denominator that is a power of 2,
regardless of precision.
>>> from sympy import Float
>>> from sympy.core.numbers import equal_valued
>>> (S.Half/4).is_same(Float(0.125, 1), equal_valued)
True
>>> Float(1, 2).is_same(Float(1, 10), equal_valued)
True
But decimals without a power of 2 denominator will compare
as not being the same.
>>> Float(0.1, 9).is_same(Float(0.1, 10), equal_valued)
False
But arbitrary differences can be ignored by supplying a function
to test the equivalence of two numbers:
>>> import math
>>> Float(0.1, 9).is_same(Float(0.1, 10), math.isclose)
True
Other objects might compare the same even though types are not the
same. This routine will only return True if two expressions are
identical in terms of class types.
>>> from sympy import eye, Basic
>>> eye(1) == S(eye(1)) # mutable vs immutable
True
>>> Basic.is_same(eye(1), S(eye(1)))
False
"""
from .numbers import Number
from .traversal import postorder_traversal as pot
for t in zip_longest(pot(a), pot(b)):
if None in t:
return False
a, b = t
if isinstance(a, Number):
if not isinstance(b, Number):
return False
if approx:
return approx(a, b)
if not (a == b and a.__class__ == b.__class__):
return False
return True
_aresame = Basic.is_same # for sake of others importing this
# key used by Mul and Add to make canonical args
_args_sortkey = cmp_to_key(Basic.compare)
# For all Basic subclasses _prepare_class_assumptions is called by
# Basic.__init_subclass__ but that method is not called for Basic itself so we
# call the function here instead.
_prepare_class_assumptions(Basic)
class Atom(Basic):
"""
A parent class for atomic things. An atom is an expression with no subexpressions.
Examples
========
Symbol, Number, Rational, Integer, ...
But not: Add, Mul, Pow, ...
"""
is_Atom = True
__slots__ = ()
def matches(self, expr, repl_dict=None, old=False):
if self == expr:
if repl_dict is None:
return {}
return repl_dict.copy()
def xreplace(self, rule, hack2=False):
return rule.get(self, self)
def doit(self, **hints):
return self
@classmethod
def class_key(cls):
return 2, 0, cls.__name__
@cacheit
def sort_key(self, order=None):
return self.class_key(), (1, (str(self),)), S.One.sort_key(), S.One
def _eval_simplify(self, **kwargs):
return self
@property
def _sorted_args(self):
# this is here as a safeguard against accidentally using _sorted_args
# on Atoms -- they cannot be rebuilt as atom.func(*atom._sorted_args)
# since there are no args. So the calling routine should be checking
# to see that this property is not called for Atoms.
raise AttributeError('Atoms have no args. It might be necessary'
' to make a check for Atoms in the calling code.')
def _atomic(e, recursive=False):
"""Return atom-like quantities as far as substitution is
concerned: Derivatives, Functions and Symbols. Do not
return any 'atoms' that are inside such quantities unless
they also appear outside, too, unless `recursive` is True.
Examples
========
>>> from sympy import Derivative, Function, cos
>>> from sympy.abc import x, y
>>> from sympy.core.basic import _atomic
>>> f = Function('f')
>>> _atomic(x + y)
{x, y}
>>> _atomic(x + f(y))
{x, f(y)}
>>> _atomic(Derivative(f(x), x) + cos(x) + y)
{y, cos(x), Derivative(f(x), x)}
"""
pot = _preorder_traversal(e)
seen = set()
if isinstance(e, Basic):
free = getattr(e, "free_symbols", None)
if free is None:
return {e}
else:
return set()
from .symbol import Symbol
from .function import Derivative, Function
atoms = set()
for p in pot:
if p in seen:
pot.skip()
continue
seen.add(p)
if isinstance(p, Symbol) and p in free:
atoms.add(p)
elif isinstance(p, (Derivative, Function)):
if not recursive:
pot.skip()
atoms.add(p)
return atoms
def _make_find_query(query):
"""Convert the argument of Basic.find() into a callable"""
try:
query = _sympify(query)
except SympifyError:
pass
if isinstance(query, type):
return lambda expr: isinstance(expr, query)
elif isinstance(query, Basic):
return lambda expr: expr.match(query) is not None
return query
# Delayed to avoid cyclic import
from .singleton import S
from .traversal import (preorder_traversal as _preorder_traversal,
iterargs, iterfreeargs)
preorder_traversal = deprecated(
"""
Using preorder_traversal from the sympy.core.basic submodule is
deprecated.
Instead, use preorder_traversal from the top-level sympy namespace, like
sympy.preorder_traversal
""",
deprecated_since_version="1.10",
active_deprecations_target="deprecated-traversal-functions-moved",
)(_preorder_traversal)
PK ]ZZZ��V+ sympy/core/cache.py""" Caching facility for SymPy """
from importlib import import_module
from typing import Callable
class _cache(list):
""" List of cached functions """
def print_cache(self):
"""print cache info"""
for item in self:
name = item.__name__
myfunc = item
while hasattr(myfunc, '__wrapped__'):
if hasattr(myfunc, 'cache_info'):
info = myfunc.cache_info()
break
else:
myfunc = myfunc.__wrapped__
else:
info = None
print(name, info)
def clear_cache(self):
"""clear cache content"""
for item in self:
myfunc = item
while hasattr(myfunc, '__wrapped__'):
if hasattr(myfunc, 'cache_clear'):
myfunc.cache_clear()
break
else:
myfunc = myfunc.__wrapped__
# global cache registry:
CACHE = _cache()
# make clear and print methods available
print_cache = CACHE.print_cache
clear_cache = CACHE.clear_cache
from functools import lru_cache, wraps
def __cacheit(maxsize):
"""caching decorator.
important: the result of cached function must be *immutable*
Examples
========
>>> from sympy import cacheit
>>> @cacheit
... def f(a, b):
... return a+b
>>> @cacheit
... def f(a, b): # noqa: F811
... return [a, b] # <-- WRONG, returns mutable object
to force cacheit to check returned results mutability and consistency,
set environment variable SYMPY_USE_CACHE to 'debug'
"""
def func_wrapper(func):
cfunc = lru_cache(maxsize, typed=True)(func)
@wraps(func)
def wrapper(*args, **kwargs):
try:
retval = cfunc(*args, **kwargs)
except TypeError as e:
if not e.args or not e.args[0].startswith('unhashable type:'):
raise
retval = func(*args, **kwargs)
return retval
wrapper.cache_info = cfunc.cache_info
wrapper.cache_clear = cfunc.cache_clear
CACHE.append(wrapper)
return wrapper
return func_wrapper
########################################
def __cacheit_nocache(func):
return func
def __cacheit_debug(maxsize):
"""cacheit + code to check cache consistency"""
def func_wrapper(func):
cfunc = __cacheit(maxsize)(func)
@wraps(func)
def wrapper(*args, **kw_args):
# always call function itself and compare it with cached version
r1 = func(*args, **kw_args)
r2 = cfunc(*args, **kw_args)
# try to see if the result is immutable
#
# this works because:
#
# hash([1,2,3]) -> raise TypeError
# hash({'a':1, 'b':2}) -> raise TypeError
# hash((1,[2,3])) -> raise TypeError
#
# hash((1,2,3)) -> just computes the hash
hash(r1), hash(r2)
# also see if returned values are the same
if r1 != r2:
raise RuntimeError("Returned values are not the same")
return r1
return wrapper
return func_wrapper
def _getenv(key, default=None):
from os import getenv
return getenv(key, default)
# SYMPY_USE_CACHE=yes/no/debug
USE_CACHE = _getenv('SYMPY_USE_CACHE', 'yes').lower()
# SYMPY_CACHE_SIZE=some_integer/None
# special cases :
# SYMPY_CACHE_SIZE=0 -> No caching
# SYMPY_CACHE_SIZE=None -> Unbounded caching
scs = _getenv('SYMPY_CACHE_SIZE', '1000')
if scs.lower() == 'none':
SYMPY_CACHE_SIZE = None
else:
try:
SYMPY_CACHE_SIZE = int(scs)
except ValueError:
raise RuntimeError(
'SYMPY_CACHE_SIZE must be a valid integer or None. ' + \
'Got: %s' % SYMPY_CACHE_SIZE)
if USE_CACHE == 'no':
cacheit = __cacheit_nocache
elif USE_CACHE == 'yes':
cacheit = __cacheit(SYMPY_CACHE_SIZE)
elif USE_CACHE == 'debug':
cacheit = __cacheit_debug(SYMPY_CACHE_SIZE) # a lot slower
else:
raise RuntimeError(
'unrecognized value for SYMPY_USE_CACHE: %s' % USE_CACHE)
def cached_property(func):
'''Decorator to cache property method'''
attrname = '__' + func.__name__
_cached_property_sentinel = object()
def propfunc(self):
val = getattr(self, attrname, _cached_property_sentinel)
if val is _cached_property_sentinel:
val = func(self)
setattr(self, attrname, val)
return val
return property(propfunc)
def lazy_function(module : str, name : str) -> Callable:
"""Create a lazy proxy for a function in a module.
The module containing the function is not imported until the function is used.
"""
func = None
def _get_function():
nonlocal func
if func is None:
func = getattr(import_module(module), name)
return func
# The metaclass is needed so that help() shows the docstring
class LazyFunctionMeta(type):
@property
def __doc__(self):
docstring = _get_function().__doc__
docstring += f"\n\nNote: this is a {self.__class__.__name__} wrapper of '{module}.{name}'"
return docstring
class LazyFunction(metaclass=LazyFunctionMeta):
def __call__(self, *args, **kwargs):
# inline get of function for performance gh-23832
nonlocal func
if func is None:
func = getattr(import_module(module), name)
return func(*args, **kwargs)
@property
def __doc__(self):
docstring = _get_function().__doc__
docstring += f"\n\nNote: this is a {self.__class__.__name__} wrapper of '{module}.{name}'"
return docstring
def __str__(self):
return _get_function().__str__()
def __repr__(self):
return f"<{__class__.__name__} object at 0x{id(self):x}>: wrapping '{module}.{name}'"
return LazyFunction()
PK ]ZZZ�pʘy y sympy/core/compatibility.py"""
.. deprecated:: 1.10
``sympy.core.compatibility`` is deprecated. See
:ref:`sympy-core-compatibility`.
Reimplementations of constructs introduced in later versions of Python than
we support. Also some functions that are needed SymPy-wide and are located
here for easy import.
"""
from sympy.utilities.exceptions import sympy_deprecation_warning
sympy_deprecation_warning("""
The sympy.core.compatibility submodule is deprecated.
This module was only ever intended for internal use. Some of the functions
that were in this module are available from the top-level SymPy namespace,
i.e.,
from sympy import ordered, default_sort_key
The remaining were only intended for internal SymPy use and should not be used
by user code.
""",
deprecated_since_version="1.10",
active_deprecations_target="deprecated-sympy-core-compatibility",
)
from .sorting import ordered, _nodes, default_sort_key # noqa:F401
from sympy.utilities.misc import as_int as _as_int # noqa:F401
from sympy.utilities.iterables import iterable, is_sequence, NotIterable # noqa:F401
PK ]ZZZϥ(�1, 1, sympy/core/containers.py"""Module for SymPy containers
(SymPy objects that store other SymPy objects)
The containers implemented in this module are subclassed to Basic.
They are supposed to work seamlessly within the SymPy framework.
"""
from collections import OrderedDict
from collections.abc import MutableSet
from typing import Any, Callable
from .basic import Basic
from .sorting import default_sort_key, ordered
from .sympify import _sympify, sympify, _sympy_converter, SympifyError
from sympy.core.kind import Kind
from sympy.utilities.iterables import iterable
from sympy.utilities.misc import as_int
class Tuple(Basic):
"""
Wrapper around the builtin tuple object.
Explanation
===========
The Tuple is a subclass of Basic, so that it works well in the
SymPy framework. The wrapped tuple is available as self.args, but
you can also access elements or slices with [:] syntax.
Parameters
==========
sympify : bool
If ``False``, ``sympify`` is not called on ``args``. This
can be used for speedups for very large tuples where the
elements are known to already be SymPy objects.
Examples
========
>>> from sympy import Tuple, symbols
>>> a, b, c, d = symbols('a b c d')
>>> Tuple(a, b, c)[1:]
(b, c)
>>> Tuple(a, b, c).subs(a, d)
(d, b, c)
"""
def __new__(cls, *args, **kwargs):
if kwargs.get('sympify', True):
args = (sympify(arg) for arg in args)
obj = Basic.__new__(cls, *args)
return obj
def __getitem__(self, i):
if isinstance(i, slice):
indices = i.indices(len(self))
return Tuple(*(self.args[j] for j in range(*indices)))
return self.args[i]
def __len__(self):
return len(self.args)
def __contains__(self, item):
return item in self.args
def __iter__(self):
return iter(self.args)
def __add__(self, other):
if isinstance(other, Tuple):
return Tuple(*(self.args + other.args))
elif isinstance(other, tuple):
return Tuple(*(self.args + other))
else:
return NotImplemented
def __radd__(self, other):
if isinstance(other, Tuple):
return Tuple(*(other.args + self.args))
elif isinstance(other, tuple):
return Tuple(*(other + self.args))
else:
return NotImplemented
def __mul__(self, other):
try:
n = as_int(other)
except ValueError:
raise TypeError("Can't multiply sequence by non-integer of type '%s'" % type(other))
return self.func(*(self.args*n))
__rmul__ = __mul__
def __eq__(self, other):
if isinstance(other, Basic):
return super().__eq__(other)
return self.args == other
def __ne__(self, other):
if isinstance(other, Basic):
return super().__ne__(other)
return self.args != other
def __hash__(self):
return hash(self.args)
def _to_mpmath(self, prec):
return tuple(a._to_mpmath(prec) for a in self.args)
def __lt__(self, other):
return _sympify(self.args < other.args)
def __le__(self, other):
return _sympify(self.args <= other.args)
# XXX: Basic defines count() as something different, so we can't
# redefine it here. Originally this lead to cse() test failure.
def tuple_count(self, value) -> int:
"""Return number of occurrences of value."""
return self.args.count(value)
def index(self, value, start=None, stop=None):
"""Searches and returns the first index of the value."""
# XXX: One would expect:
#
# return self.args.index(value, start, stop)
#
# here. Any trouble with that? Yes:
#
# >>> (1,).index(1, None, None)
# Traceback (most recent call last):
# File "<stdin>", line 1, in <module>
# TypeError: slice indices must be integers or None or have an __index__ method
#
# See: http://bugs.python.org/issue13340
if start is None and stop is None:
return self.args.index(value)
elif stop is None:
return self.args.index(value, start)
else:
return self.args.index(value, start, stop)
@property
def kind(self):
"""
The kind of a Tuple instance.
The kind of a Tuple is always of :class:`TupleKind` but
parametrised by the number of elements and the kind of each element.
Examples
========
>>> from sympy import Tuple, Matrix
>>> Tuple(1, 2).kind
TupleKind(NumberKind, NumberKind)
>>> Tuple(Matrix([1, 2]), 1).kind
TupleKind(MatrixKind(NumberKind), NumberKind)
>>> Tuple(1, 2).kind.element_kind
(NumberKind, NumberKind)
See Also
========
sympy.matrices.kind.MatrixKind
sympy.core.kind.NumberKind
"""
return TupleKind(*(i.kind for i in self.args))
_sympy_converter[tuple] = lambda tup: Tuple(*tup)
def tuple_wrapper(method):
"""
Decorator that converts any tuple in the function arguments into a Tuple.
Explanation
===========
The motivation for this is to provide simple user interfaces. The user can
call a function with regular tuples in the argument, and the wrapper will
convert them to Tuples before handing them to the function.
Explanation
===========
>>> from sympy.core.containers import tuple_wrapper
>>> def f(*args):
... return args
>>> g = tuple_wrapper(f)
The decorated function g sees only the Tuple argument:
>>> g(0, (1, 2), 3)
(0, (1, 2), 3)
"""
def wrap_tuples(*args, **kw_args):
newargs = []
for arg in args:
if isinstance(arg, tuple):
newargs.append(Tuple(*arg))
else:
newargs.append(arg)
return method(*newargs, **kw_args)
return wrap_tuples
class Dict(Basic):
"""
Wrapper around the builtin dict object.
Explanation
===========
The Dict is a subclass of Basic, so that it works well in the
SymPy framework. Because it is immutable, it may be included
in sets, but its values must all be given at instantiation and
cannot be changed afterwards. Otherwise it behaves identically
to the Python dict.
Examples
========
>>> from sympy import Dict, Symbol
>>> D = Dict({1: 'one', 2: 'two'})
>>> for key in D:
... if key == 1:
... print('%s %s' % (key, D[key]))
1 one
The args are sympified so the 1 and 2 are Integers and the values
are Symbols. Queries automatically sympify args so the following work:
>>> 1 in D
True
>>> D.has(Symbol('one')) # searches keys and values
True
>>> 'one' in D # not in the keys
False
>>> D[1]
one
"""
def __new__(cls, *args):
if len(args) == 1 and isinstance(args[0], (dict, Dict)):
items = [Tuple(k, v) for k, v in args[0].items()]
elif iterable(args) and all(len(arg) == 2 for arg in args):
items = [Tuple(k, v) for k, v in args]
else:
raise TypeError('Pass Dict args as Dict((k1, v1), ...) or Dict({k1: v1, ...})')
elements = frozenset(items)
obj = Basic.__new__(cls, *ordered(items))
obj.elements = elements
obj._dict = dict(items) # In case Tuple decides it wants to sympify
return obj
def __getitem__(self, key):
"""x.__getitem__(y) <==> x[y]"""
try:
key = _sympify(key)
except SympifyError:
raise KeyError(key)
return self._dict[key]
def __setitem__(self, key, value):
raise NotImplementedError("SymPy Dicts are Immutable")
def items(self):
'''Returns a set-like object providing a view on dict's items.
'''
return self._dict.items()
def keys(self):
'''Returns the list of the dict's keys.'''
return self._dict.keys()
def values(self):
'''Returns the list of the dict's values.'''
return self._dict.values()
def __iter__(self):
'''x.__iter__() <==> iter(x)'''
return iter(self._dict)
def __len__(self):
'''x.__len__() <==> len(x)'''
return self._dict.__len__()
def get(self, key, default=None):
'''Returns the value for key if the key is in the dictionary.'''
try:
key = _sympify(key)
except SympifyError:
return default
return self._dict.get(key, default)
def __contains__(self, key):
'''D.__contains__(k) -> True if D has a key k, else False'''
try:
key = _sympify(key)
except SympifyError:
return False
return key in self._dict
def __lt__(self, other):
return _sympify(self.args < other.args)
@property
def _sorted_args(self):
return tuple(sorted(self.args, key=default_sort_key))
def __eq__(self, other):
if isinstance(other, dict):
return self == Dict(other)
return super().__eq__(other)
__hash__ : Callable[[Basic], Any] = Basic.__hash__
# this handles dict, defaultdict, OrderedDict
_sympy_converter[dict] = lambda d: Dict(*d.items())
class OrderedSet(MutableSet):
def __init__(self, iterable=None):
if iterable:
self.map = OrderedDict((item, None) for item in iterable)
else:
self.map = OrderedDict()
def __len__(self):
return len(self.map)
def __contains__(self, key):
return key in self.map
def add(self, key):
self.map[key] = None
def discard(self, key):
self.map.pop(key)
def pop(self, last=True):
return self.map.popitem(last=last)[0]
def __iter__(self):
yield from self.map.keys()
def __repr__(self):
if not self.map:
return '%s()' % (self.__class__.__name__,)
return '%s(%r)' % (self.__class__.__name__, list(self.map.keys()))
def intersection(self, other):
return self.__class__([val for val in self if val in other])
def difference(self, other):
return self.__class__([val for val in self if val not in other])
def update(self, iterable):
for val in iterable:
self.add(val)
class TupleKind(Kind):
"""
TupleKind is a subclass of Kind, which is used to define Kind of ``Tuple``.
Parameters of TupleKind will be kinds of all the arguments in Tuples, for
example
Parameters
==========
args : tuple(element_kind)
element_kind is kind of element.
args is tuple of kinds of element
Examples
========
>>> from sympy import Tuple
>>> Tuple(1, 2).kind
TupleKind(NumberKind, NumberKind)
>>> Tuple(1, 2).kind.element_kind
(NumberKind, NumberKind)
See Also
========
sympy.core.kind.NumberKind
MatrixKind
sympy.sets.sets.SetKind
"""
def __new__(cls, *args):
obj = super().__new__(cls, *args)
obj.element_kind = args
return obj
def __repr__(self):
return "TupleKind{}".format(self.element_kind)
PK ]ZZZ�l# # sympy/core/core.py""" The core's core. """
from __future__ import annotations
class Registry:
"""
Base class for registry objects.
Registries map a name to an object using attribute notation. Registry
classes behave singletonically: all their instances share the same state,
which is stored in the class object.
All subclasses should set `__slots__ = ()`.
"""
__slots__ = ()
def __setattr__(self, name, obj):
setattr(self.__class__, name, obj)
def __delattr__(self, name):
delattr(self.__class__, name)
PK ]ZZZ�o� sympy/core/coreerrors.py"""Definitions of common exceptions for :mod:`sympy.core` module. """
class BaseCoreError(Exception):
"""Base class for core related exceptions. """
class NonCommutativeExpression(BaseCoreError):
"""Raised when expression didn't have commutative property. """
PK ]ZZZT_ sympy/core/decorators.py"""
SymPy core decorators.
The purpose of this module is to expose decorators without any other
dependencies, so that they can be easily imported anywhere in sympy/core.
"""
from functools import wraps
from .sympify import SympifyError, sympify
def _sympifyit(arg, retval=None):
"""
decorator to smartly _sympify function arguments
Explanation
===========
@_sympifyit('other', NotImplemented)
def add(self, other):
...
In add, other can be thought of as already being a SymPy object.
If it is not, the code is likely to catch an exception, then other will
be explicitly _sympified, and the whole code restarted.
if _sympify(arg) fails, NotImplemented will be returned
See also
========
__sympifyit
"""
def deco(func):
return __sympifyit(func, arg, retval)
return deco
def __sympifyit(func, arg, retval=None):
"""Decorator to _sympify `arg` argument for function `func`.
Do not use directly -- use _sympifyit instead.
"""
# we support f(a,b) only
if not func.__code__.co_argcount:
raise LookupError("func not found")
# only b is _sympified
assert func.__code__.co_varnames[1] == arg
if retval is None:
@wraps(func)
def __sympifyit_wrapper(a, b):
return func(a, sympify(b, strict=True))
else:
@wraps(func)
def __sympifyit_wrapper(a, b):
try:
# If an external class has _op_priority, it knows how to deal
# with SymPy objects. Otherwise, it must be converted.
if not hasattr(b, '_op_priority'):
b = sympify(b, strict=True)
return func(a, b)
except SympifyError:
return retval
return __sympifyit_wrapper
def call_highest_priority(method_name):
"""A decorator for binary special methods to handle _op_priority.
Explanation
===========
Binary special methods in Expr and its subclasses use a special attribute
'_op_priority' to determine whose special method will be called to
handle the operation. In general, the object having the highest value of
'_op_priority' will handle the operation. Expr and subclasses that define
custom binary special methods (__mul__, etc.) should decorate those
methods with this decorator to add the priority logic.
The ``method_name`` argument is the name of the method of the other class
that will be called. Use this decorator in the following manner::
# Call other.__rmul__ if other._op_priority > self._op_priority
@call_highest_priority('__rmul__')
def __mul__(self, other):
...
# Call other.__mul__ if other._op_priority > self._op_priority
@call_highest_priority('__mul__')
def __rmul__(self, other):
...
"""
def priority_decorator(func):
@wraps(func)
def binary_op_wrapper(self, other):
if hasattr(other, '_op_priority'):
if other._op_priority > self._op_priority:
f = getattr(other, method_name, None)
if f is not None:
return f(self)
return func(self, other)
return binary_op_wrapper
return priority_decorator
def sympify_method_args(cls):
'''Decorator for a class with methods that sympify arguments.
Explanation
===========
The sympify_method_args decorator is to be used with the sympify_return
decorator for automatic sympification of method arguments. This is
intended for the common idiom of writing a class like :
Examples
========
>>> from sympy import Basic, SympifyError, S
>>> from sympy.core.sympify import _sympify
>>> class MyTuple(Basic):
... def __add__(self, other):
... try:
... other = _sympify(other)
... except SympifyError:
... return NotImplemented
... if not isinstance(other, MyTuple):
... return NotImplemented
... return MyTuple(*(self.args + other.args))
>>> MyTuple(S(1), S(2)) + MyTuple(S(3), S(4))
MyTuple(1, 2, 3, 4)
In the above it is important that we return NotImplemented when other is
not sympifiable and also when the sympified result is not of the expected
type. This allows the MyTuple class to be used cooperatively with other
classes that overload __add__ and want to do something else in combination
with instance of Tuple.
Using this decorator the above can be written as
>>> from sympy.core.decorators import sympify_method_args, sympify_return
>>> @sympify_method_args
... class MyTuple(Basic):
... @sympify_return([('other', 'MyTuple')], NotImplemented)
... def __add__(self, other):
... return MyTuple(*(self.args + other.args))
>>> MyTuple(S(1), S(2)) + MyTuple(S(3), S(4))
MyTuple(1, 2, 3, 4)
The idea here is that the decorators take care of the boiler-plate code
for making this happen in each method that potentially needs to accept
unsympified arguments. Then the body of e.g. the __add__ method can be
written without needing to worry about calling _sympify or checking the
type of the resulting object.
The parameters for sympify_return are a list of tuples of the form
(parameter_name, expected_type) and the value to return (e.g.
NotImplemented). The expected_type parameter can be a type e.g. Tuple or a
string 'Tuple'. Using a string is useful for specifying a Type within its
class body (as in the above example).
Notes: Currently sympify_return only works for methods that take a single
argument (not including self). Specifying an expected_type as a string
only works for the class in which the method is defined.
'''
# Extract the wrapped methods from each of the wrapper objects created by
# the sympify_return decorator. Doing this here allows us to provide the
# cls argument which is used for forward string referencing.
for attrname, obj in cls.__dict__.items():
if isinstance(obj, _SympifyWrapper):
setattr(cls, attrname, obj.make_wrapped(cls))
return cls
def sympify_return(*args):
'''Function/method decorator to sympify arguments automatically
See the docstring of sympify_method_args for explanation.
'''
# Store a wrapper object for the decorated method
def wrapper(func):
return _SympifyWrapper(func, args)
return wrapper
class _SympifyWrapper:
'''Internal class used by sympify_return and sympify_method_args'''
def __init__(self, func, args):
self.func = func
self.args = args
def make_wrapped(self, cls):
func = self.func
parameters, retval = self.args
# XXX: Handle more than one parameter?
[(parameter, expectedcls)] = parameters
# Handle forward references to the current class using strings
if expectedcls == cls.__name__:
expectedcls = cls
# Raise RuntimeError since this is a failure at import time and should
# not be recoverable.
nargs = func.__code__.co_argcount
# we support f(a, b) only
if nargs != 2:
raise RuntimeError('sympify_return can only be used with 2 argument functions')
# only b is _sympified
if func.__code__.co_varnames[1] != parameter:
raise RuntimeError('parameter name mismatch "%s" in %s' %
(parameter, func.__name__))
@wraps(func)
def _func(self, other):
# XXX: The check for _op_priority here should be removed. It is
# needed to stop mutable matrices from being sympified to
# immutable matrices which breaks things in quantum...
if not hasattr(other, '_op_priority'):
try:
other = sympify(other, strict=True)
except SympifyError:
return retval
if not isinstance(other, expectedcls):
return retval
return func(self, other)
return _func
PK ]ZZZᡮq�� �� sympy/core/evalf.py"""
Adaptive numerical evaluation of SymPy expressions, using mpmath
for mathematical functions.
"""
from __future__ import annotations
from typing import Tuple as tTuple, Optional, Union as tUnion, Callable, List, Dict as tDict, Type, TYPE_CHECKING, \
Any, overload
import math
import mpmath.libmp as libmp
from mpmath import (
make_mpc, make_mpf, mp, mpc, mpf, nsum, quadts, quadosc, workprec)
from mpmath import inf as mpmath_inf
from mpmath.libmp import (from_int, from_man_exp, from_rational, fhalf,
fnan, finf, fninf, fnone, fone, fzero, mpf_abs, mpf_add,
mpf_atan, mpf_atan2, mpf_cmp, mpf_cos, mpf_e, mpf_exp, mpf_log, mpf_lt,
mpf_mul, mpf_neg, mpf_pi, mpf_pow, mpf_pow_int, mpf_shift, mpf_sin,
mpf_sqrt, normalize, round_nearest, to_int, to_str)
from mpmath.libmp import bitcount as mpmath_bitcount
from mpmath.libmp.backend import MPZ
from mpmath.libmp.libmpc import _infs_nan
from mpmath.libmp.libmpf import dps_to_prec, prec_to_dps
from .sympify import sympify
from .singleton import S
from sympy.external.gmpy import SYMPY_INTS
from sympy.utilities.iterables import is_sequence
from sympy.utilities.lambdify import lambdify
from sympy.utilities.misc import as_int
if TYPE_CHECKING:
from sympy.core.expr import Expr
from sympy.core.add import Add
from sympy.core.mul import Mul
from sympy.core.power import Pow
from sympy.core.symbol import Symbol
from sympy.integrals.integrals import Integral
from sympy.concrete.summations import Sum
from sympy.concrete.products import Product
from sympy.functions.elementary.exponential import exp, log
from sympy.functions.elementary.complexes import Abs, re, im
from sympy.functions.elementary.integers import ceiling, floor
from sympy.functions.elementary.trigonometric import atan
from .numbers import Float, Rational, Integer, AlgebraicNumber, Number
LG10 = math.log2(10)
rnd = round_nearest
def bitcount(n):
"""Return smallest integer, b, such that |n|/2**b < 1.
"""
return mpmath_bitcount(abs(int(n)))
# Used in a few places as placeholder values to denote exponents and
# precision levels, e.g. of exact numbers. Must be careful to avoid
# passing these to mpmath functions or returning them in final results.
INF = float(mpmath_inf)
MINUS_INF = float(-mpmath_inf)
# ~= 100 digits. Real men set this to INF.
DEFAULT_MAXPREC = 333
class PrecisionExhausted(ArithmeticError):
pass
#----------------------------------------------------------------------------#
# #
# Helper functions for arithmetic and complex parts #
# #
#----------------------------------------------------------------------------#
"""
An mpf value tuple is a tuple of integers (sign, man, exp, bc)
representing a floating-point number: [1, -1][sign]*man*2**exp where
sign is 0 or 1 and bc should correspond to the number of bits used to
represent the mantissa (man) in binary notation, e.g.
"""
MPF_TUP = tTuple[int, int, int, int] # mpf value tuple
"""
Explanation
===========
>>> from sympy.core.evalf import bitcount
>>> sign, man, exp, bc = 0, 5, 1, 3
>>> n = [1, -1][sign]*man*2**exp
>>> n, bitcount(man)
(10, 3)
A temporary result is a tuple (re, im, re_acc, im_acc) where
re and im are nonzero mpf value tuples representing approximate
numbers, or None to denote exact zeros.
re_acc, im_acc are integers denoting log2(e) where e is the estimated
relative accuracy of the respective complex part, but may be anything
if the corresponding complex part is None.
"""
TMP_RES = Any # temporary result, should be some variant of
# tUnion[tTuple[Optional[MPF_TUP], Optional[MPF_TUP],
# Optional[int], Optional[int]],
# 'ComplexInfinity']
# but mypy reports error because it doesn't know as we know
# 1. re and re_acc are either both None or both MPF_TUP
# 2. sometimes the result can't be zoo
# type of the "options" parameter in internal evalf functions
OPT_DICT = tDict[str, Any]
def fastlog(x: Optional[MPF_TUP]) -> tUnion[int, Any]:
"""Fast approximation of log2(x) for an mpf value tuple x.
Explanation
===========
Calculated as exponent + width of mantissa. This is an
approximation for two reasons: 1) it gives the ceil(log2(abs(x)))
value and 2) it is too high by 1 in the case that x is an exact
power of 2. Although this is easy to remedy by testing to see if
the odd mpf mantissa is 1 (indicating that one was dealing with
an exact power of 2) that would decrease the speed and is not
necessary as this is only being used as an approximation for the
number of bits in x. The correct return value could be written as
"x[2] + (x[3] if x[1] != 1 else 0)".
Since mpf tuples always have an odd mantissa, no check is done
to see if the mantissa is a multiple of 2 (in which case the
result would be too large by 1).
Examples
========
>>> from sympy import log
>>> from sympy.core.evalf import fastlog, bitcount
>>> s, m, e = 0, 5, 1
>>> bc = bitcount(m)
>>> n = [1, -1][s]*m*2**e
>>> n, (log(n)/log(2)).evalf(2), fastlog((s, m, e, bc))
(10, 3.3, 4)
"""
if not x or x == fzero:
return MINUS_INF
return x[2] + x[3]
def pure_complex(v: 'Expr', or_real=False) -> tuple['Number', 'Number'] | None:
"""Return a and b if v matches a + I*b where b is not zero and
a and b are Numbers, else None. If `or_real` is True then 0 will
be returned for `b` if `v` is a real number.
Examples
========
>>> from sympy.core.evalf import pure_complex
>>> from sympy import sqrt, I, S
>>> a, b, surd = S(2), S(3), sqrt(2)
>>> pure_complex(a)
>>> pure_complex(a, or_real=True)
(2, 0)
>>> pure_complex(surd)
>>> pure_complex(a + b*I)
(2, 3)
>>> pure_complex(I)
(0, 1)
"""
h, t = v.as_coeff_Add()
if t:
c, i = t.as_coeff_Mul()
if i is S.ImaginaryUnit:
return h, c
elif or_real:
return h, S.Zero
return None
# I don't know what this is, see function scaled_zero below
SCALED_ZERO_TUP = tTuple[List[int], int, int, int]
@overload
def scaled_zero(mag: SCALED_ZERO_TUP, sign=1) -> MPF_TUP:
...
@overload
def scaled_zero(mag: int, sign=1) -> tTuple[SCALED_ZERO_TUP, int]:
...
def scaled_zero(mag: tUnion[SCALED_ZERO_TUP, int], sign=1) -> \
tUnion[MPF_TUP, tTuple[SCALED_ZERO_TUP, int]]:
"""Return an mpf representing a power of two with magnitude ``mag``
and -1 for precision. Or, if ``mag`` is a scaled_zero tuple, then just
remove the sign from within the list that it was initially wrapped
in.
Examples
========
>>> from sympy.core.evalf import scaled_zero
>>> from sympy import Float
>>> z, p = scaled_zero(100)
>>> z, p
(([0], 1, 100, 1), -1)
>>> ok = scaled_zero(z)
>>> ok
(0, 1, 100, 1)
>>> Float(ok)
1.26765060022823e+30
>>> Float(ok, p)
0.e+30
>>> ok, p = scaled_zero(100, -1)
>>> Float(scaled_zero(ok), p)
-0.e+30
"""
if isinstance(mag, tuple) and len(mag) == 4 and iszero(mag, scaled=True):
return (mag[0][0],) + mag[1:]
elif isinstance(mag, SYMPY_INTS):
if sign not in [-1, 1]:
raise ValueError('sign must be +/-1')
rv, p = mpf_shift(fone, mag), -1
s = 0 if sign == 1 else 1
rv = ([s],) + rv[1:]
return rv, p
else:
raise ValueError('scaled zero expects int or scaled_zero tuple.')
def iszero(mpf: tUnion[MPF_TUP, SCALED_ZERO_TUP, None], scaled=False) -> Optional[bool]:
if not scaled:
return not mpf or not mpf[1] and not mpf[-1]
return mpf and isinstance(mpf[0], list) and mpf[1] == mpf[-1] == 1
def complex_accuracy(result: TMP_RES) -> tUnion[int, Any]:
"""
Returns relative accuracy of a complex number with given accuracies
for the real and imaginary parts. The relative accuracy is defined
in the complex norm sense as ||z|+|error|| / |z| where error
is equal to (real absolute error) + (imag absolute error)*i.
The full expression for the (logarithmic) error can be approximated
easily by using the max norm to approximate the complex norm.
In the worst case (re and im equal), this is wrong by a factor
sqrt(2), or by log2(sqrt(2)) = 0.5 bit.
"""
if result is S.ComplexInfinity:
return INF
re, im, re_acc, im_acc = result
if not im:
if not re:
return INF
return re_acc
if not re:
return im_acc
re_size = fastlog(re)
im_size = fastlog(im)
absolute_error = max(re_size - re_acc, im_size - im_acc)
relative_error = absolute_error - max(re_size, im_size)
return -relative_error
def get_abs(expr: 'Expr', prec: int, options: OPT_DICT) -> TMP_RES:
result = evalf(expr, prec + 2, options)
if result is S.ComplexInfinity:
return finf, None, prec, None
re, im, re_acc, im_acc = result
if not re:
re, re_acc, im, im_acc = im, im_acc, re, re_acc
if im:
if expr.is_number:
abs_expr, _, acc, _ = evalf(abs(N(expr, prec + 2)),
prec + 2, options)
return abs_expr, None, acc, None
else:
if 'subs' in options:
return libmp.mpc_abs((re, im), prec), None, re_acc, None
return abs(expr), None, prec, None
elif re:
return mpf_abs(re), None, re_acc, None
else:
return None, None, None, None
def get_complex_part(expr: 'Expr', no: int, prec: int, options: OPT_DICT) -> TMP_RES:
"""no = 0 for real part, no = 1 for imaginary part"""
workprec = prec
i = 0
while 1:
res = evalf(expr, workprec, options)
if res is S.ComplexInfinity:
return fnan, None, prec, None
value, accuracy = res[no::2]
# XXX is the last one correct? Consider re((1+I)**2).n()
if (not value) or accuracy >= prec or -value[2] > prec:
return value, None, accuracy, None
workprec += max(30, 2**i)
i += 1
def evalf_abs(expr: 'Abs', prec: int, options: OPT_DICT) -> TMP_RES:
return get_abs(expr.args[0], prec, options)
def evalf_re(expr: 're', prec: int, options: OPT_DICT) -> TMP_RES:
return get_complex_part(expr.args[0], 0, prec, options)
def evalf_im(expr: 'im', prec: int, options: OPT_DICT) -> TMP_RES:
return get_complex_part(expr.args[0], 1, prec, options)
def finalize_complex(re: MPF_TUP, im: MPF_TUP, prec: int) -> TMP_RES:
if re == fzero and im == fzero:
raise ValueError("got complex zero with unknown accuracy")
elif re == fzero:
return None, im, None, prec
elif im == fzero:
return re, None, prec, None
size_re = fastlog(re)
size_im = fastlog(im)
if size_re > size_im:
re_acc = prec
im_acc = prec + min(-(size_re - size_im), 0)
else:
im_acc = prec
re_acc = prec + min(-(size_im - size_re), 0)
return re, im, re_acc, im_acc
def chop_parts(value: TMP_RES, prec: int) -> TMP_RES:
"""
Chop off tiny real or complex parts.
"""
if value is S.ComplexInfinity:
return value
re, im, re_acc, im_acc = value
# Method 1: chop based on absolute value
if re and re not in _infs_nan and (fastlog(re) < -prec + 4):
re, re_acc = None, None
if im and im not in _infs_nan and (fastlog(im) < -prec + 4):
im, im_acc = None, None
# Method 2: chop if inaccurate and relatively small
if re and im:
delta = fastlog(re) - fastlog(im)
if re_acc < 2 and (delta - re_acc <= -prec + 4):
re, re_acc = None, None
if im_acc < 2 and (delta - im_acc >= prec - 4):
im, im_acc = None, None
return re, im, re_acc, im_acc
def check_target(expr: 'Expr', result: TMP_RES, prec: int):
a = complex_accuracy(result)
if a < prec:
raise PrecisionExhausted("Failed to distinguish the expression: \n\n%s\n\n"
"from zero. Try simplifying the input, using chop=True, or providing "
"a higher maxn for evalf" % (expr))
def get_integer_part(expr: 'Expr', no: int, options: OPT_DICT, return_ints=False) -> \
tUnion[TMP_RES, tTuple[int, int]]:
"""
With no = 1, computes ceiling(expr)
With no = -1, computes floor(expr)
Note: this function either gives the exact result or signals failure.
"""
from sympy.functions.elementary.complexes import re, im
# The expression is likely less than 2^30 or so
assumed_size = 30
result = evalf(expr, assumed_size, options)
if result is S.ComplexInfinity:
raise ValueError("Cannot get integer part of Complex Infinity")
ire, iim, ire_acc, iim_acc = result
# We now know the size, so we can calculate how much extra precision
# (if any) is needed to get within the nearest integer
if ire and iim:
gap = max(fastlog(ire) - ire_acc, fastlog(iim) - iim_acc)
elif ire:
gap = fastlog(ire) - ire_acc
elif iim:
gap = fastlog(iim) - iim_acc
else:
# ... or maybe the expression was exactly zero
if return_ints:
return 0, 0
else:
return None, None, None, None
margin = 10
if gap >= -margin:
prec = margin + assumed_size + gap
ire, iim, ire_acc, iim_acc = evalf(
expr, prec, options)
else:
prec = assumed_size
# We can now easily find the nearest integer, but to find floor/ceil, we
# must also calculate whether the difference to the nearest integer is
# positive or negative (which may fail if very close).
def calc_part(re_im: 'Expr', nexpr: MPF_TUP):
from .add import Add
_, _, exponent, _ = nexpr
is_int = exponent == 0
nint = int(to_int(nexpr, rnd))
if is_int:
# make sure that we had enough precision to distinguish
# between nint and the re or im part (re_im) of expr that
# was passed to calc_part
ire, iim, ire_acc, iim_acc = evalf(
re_im - nint, 10, options) # don't need much precision
assert not iim
size = -fastlog(ire) + 2 # -ve b/c ire is less than 1
if size > prec:
ire, iim, ire_acc, iim_acc = evalf(
re_im, size, options)
assert not iim
nexpr = ire
nint = int(to_int(nexpr, rnd))
_, _, new_exp, _ = ire
is_int = new_exp == 0
if not is_int:
# if there are subs and they all contain integer re/im parts
# then we can (hopefully) safely substitute them into the
# expression
s = options.get('subs', False)
if s:
# use strict=False with as_int because we take
# 2.0 == 2
def is_int_reim(x):
"""Check for integer or integer + I*integer."""
try:
as_int(x, strict=False)
return True
except ValueError:
try:
[as_int(i, strict=False) for i in x.as_real_imag()]
return True
except ValueError:
return False
if all(is_int_reim(v) for v in s.values()):
re_im = re_im.subs(s)
re_im = Add(re_im, -nint, evaluate=False)
x, _, x_acc, _ = evalf(re_im, 10, options)
try:
check_target(re_im, (x, None, x_acc, None), 3)
except PrecisionExhausted:
if not re_im.equals(0):
raise PrecisionExhausted
x = fzero
nint += int(no*(mpf_cmp(x or fzero, fzero) == no))
nint = from_int(nint)
return nint, INF
re_, im_, re_acc, im_acc = None, None, None, None
if ire:
re_, re_acc = calc_part(re(expr, evaluate=False), ire)
if iim:
im_, im_acc = calc_part(im(expr, evaluate=False), iim)
if return_ints:
return int(to_int(re_ or fzero)), int(to_int(im_ or fzero))
return re_, im_, re_acc, im_acc
def evalf_ceiling(expr: 'ceiling', prec: int, options: OPT_DICT) -> TMP_RES:
return get_integer_part(expr.args[0], 1, options)
def evalf_floor(expr: 'floor', prec: int, options: OPT_DICT) -> TMP_RES:
return get_integer_part(expr.args[0], -1, options)
def evalf_float(expr: 'Float', prec: int, options: OPT_DICT) -> TMP_RES:
return expr._mpf_, None, prec, None
def evalf_rational(expr: 'Rational', prec: int, options: OPT_DICT) -> TMP_RES:
return from_rational(expr.p, expr.q, prec), None, prec, None
def evalf_integer(expr: 'Integer', prec: int, options: OPT_DICT) -> TMP_RES:
return from_int(expr.p, prec), None, prec, None
#----------------------------------------------------------------------------#
# #
# Arithmetic operations #
# #
#----------------------------------------------------------------------------#
def add_terms(terms: list, prec: int, target_prec: int) -> \
tTuple[tUnion[MPF_TUP, SCALED_ZERO_TUP, None], Optional[int]]:
"""
Helper for evalf_add. Adds a list of (mpfval, accuracy) terms.
Returns
=======
- None, None if there are no non-zero terms;
- terms[0] if there is only 1 term;
- scaled_zero if the sum of the terms produces a zero by cancellation
e.g. mpfs representing 1 and -1 would produce a scaled zero which need
special handling since they are not actually zero and they are purposely
malformed to ensure that they cannot be used in anything but accuracy
calculations;
- a tuple that is scaled to target_prec that corresponds to the
sum of the terms.
The returned mpf tuple will be normalized to target_prec; the input
prec is used to define the working precision.
XXX explain why this is needed and why one cannot just loop using mpf_add
"""
terms = [t for t in terms if not iszero(t[0])]
if not terms:
return None, None
elif len(terms) == 1:
return terms[0]
# see if any argument is NaN or oo and thus warrants a special return
special = []
from .numbers import Float
for t in terms:
arg = Float._new(t[0], 1)
if arg is S.NaN or arg.is_infinite:
special.append(arg)
if special:
from .add import Add
rv = evalf(Add(*special), prec + 4, {})
return rv[0], rv[2]
working_prec = 2*prec
sum_man, sum_exp = 0, 0
absolute_err: List[int] = []
for x, accuracy in terms:
sign, man, exp, bc = x
if sign:
man = -man
absolute_err.append(bc + exp - accuracy)
delta = exp - sum_exp
if exp >= sum_exp:
# x much larger than existing sum?
# first: quick test
if ((delta > working_prec) and
((not sum_man) or
delta - bitcount(abs(sum_man)) > working_prec)):
sum_man = man
sum_exp = exp
else:
sum_man += (man << delta)
else:
delta = -delta
# x much smaller than existing sum?
if delta - bc > working_prec:
if not sum_man:
sum_man, sum_exp = man, exp
else:
sum_man = (sum_man << delta) + man
sum_exp = exp
absolute_error = max(absolute_err)
if not sum_man:
return scaled_zero(absolute_error)
if sum_man < 0:
sum_sign = 1
sum_man = -sum_man
else:
sum_sign = 0
sum_bc = bitcount(sum_man)
sum_accuracy = sum_exp + sum_bc - absolute_error
r = normalize(sum_sign, sum_man, sum_exp, sum_bc, target_prec,
rnd), sum_accuracy
return r
def evalf_add(v: 'Add', prec: int, options: OPT_DICT) -> TMP_RES:
res = pure_complex(v)
if res:
h, c = res
re, _, re_acc, _ = evalf(h, prec, options)
im, _, im_acc, _ = evalf(c, prec, options)
return re, im, re_acc, im_acc
oldmaxprec = options.get('maxprec', DEFAULT_MAXPREC)
i = 0
target_prec = prec
while 1:
options['maxprec'] = min(oldmaxprec, 2*prec)
terms = [evalf(arg, prec + 10, options) for arg in v.args]
n = terms.count(S.ComplexInfinity)
if n >= 2:
return fnan, None, prec, None
re, re_acc = add_terms(
[a[0::2] for a in terms if isinstance(a, tuple) and a[0]], prec, target_prec)
im, im_acc = add_terms(
[a[1::2] for a in terms if isinstance(a, tuple) and a[1]], prec, target_prec)
if n == 1:
if re in (finf, fninf, fnan) or im in (finf, fninf, fnan):
return fnan, None, prec, None
return S.ComplexInfinity
acc = complex_accuracy((re, im, re_acc, im_acc))
if acc >= target_prec:
if options.get('verbose'):
print("ADD: wanted", target_prec, "accurate bits, got", re_acc, im_acc)
break
else:
if (prec - target_prec) > options['maxprec']:
break
prec = prec + max(10 + 2**i, target_prec - acc)
i += 1
if options.get('verbose'):
print("ADD: restarting with prec", prec)
options['maxprec'] = oldmaxprec
if iszero(re, scaled=True):
re = scaled_zero(re)
if iszero(im, scaled=True):
im = scaled_zero(im)
return re, im, re_acc, im_acc
def evalf_mul(v: 'Mul', prec: int, options: OPT_DICT) -> TMP_RES:
res = pure_complex(v)
if res:
# the only pure complex that is a mul is h*I
_, h = res
im, _, im_acc, _ = evalf(h, prec, options)
return None, im, None, im_acc
args = list(v.args)
# see if any argument is NaN or oo and thus warrants a special return
has_zero = False
special = []
from .numbers import Float
for arg in args:
result = evalf(arg, prec, options)
if result is S.ComplexInfinity:
special.append(result)
continue
if result[0] is None:
if result[1] is None:
has_zero = True
continue
num = Float._new(result[0], 1)
if num is S.NaN:
return fnan, None, prec, None
if num.is_infinite:
special.append(num)
if special:
if has_zero:
return fnan, None, prec, None
from .mul import Mul
return evalf(Mul(*special), prec + 4, {})
if has_zero:
return None, None, None, None
# With guard digits, multiplication in the real case does not destroy
# accuracy. This is also true in the complex case when considering the
# total accuracy; however accuracy for the real or imaginary parts
# separately may be lower.
acc = prec
# XXX: big overestimate
working_prec = prec + len(args) + 5
# Empty product is 1
start = man, exp, bc = MPZ(1), 0, 1
# First, we multiply all pure real or pure imaginary numbers.
# direction tells us that the result should be multiplied by
# I**direction; all other numbers get put into complex_factors
# to be multiplied out after the first phase.
last = len(args)
direction = 0
args.append(S.One)
complex_factors = []
for i, arg in enumerate(args):
if i != last and pure_complex(arg):
args[-1] = (args[-1]*arg).expand()
continue
elif i == last and arg is S.One:
continue
re, im, re_acc, im_acc = evalf(arg, working_prec, options)
if re and im:
complex_factors.append((re, im, re_acc, im_acc))
continue
elif re:
(s, m, e, b), w_acc = re, re_acc
elif im:
(s, m, e, b), w_acc = im, im_acc
direction += 1
else:
return None, None, None, None
direction += 2*s
man *= m
exp += e
bc += b
while bc > 3*working_prec:
man >>= working_prec
exp += working_prec
bc -= working_prec
acc = min(acc, w_acc)
sign = (direction & 2) >> 1
if not complex_factors:
v = normalize(sign, man, exp, bitcount(man), prec, rnd)
# multiply by i
if direction & 1:
return None, v, None, acc
else:
return v, None, acc, None
else:
# initialize with the first term
if (man, exp, bc) != start:
# there was a real part; give it an imaginary part
re, im = (sign, man, exp, bitcount(man)), (0, MPZ(0), 0, 0)
i0 = 0
else:
# there is no real part to start (other than the starting 1)
wre, wim, wre_acc, wim_acc = complex_factors[0]
acc = min(acc,
complex_accuracy((wre, wim, wre_acc, wim_acc)))
re = wre
im = wim
i0 = 1
for wre, wim, wre_acc, wim_acc in complex_factors[i0:]:
# acc is the overall accuracy of the product; we aren't
# computing exact accuracies of the product.
acc = min(acc,
complex_accuracy((wre, wim, wre_acc, wim_acc)))
use_prec = working_prec
A = mpf_mul(re, wre, use_prec)
B = mpf_mul(mpf_neg(im), wim, use_prec)
C = mpf_mul(re, wim, use_prec)
D = mpf_mul(im, wre, use_prec)
re = mpf_add(A, B, use_prec)
im = mpf_add(C, D, use_prec)
if options.get('verbose'):
print("MUL: wanted", prec, "accurate bits, got", acc)
# multiply by I
if direction & 1:
re, im = mpf_neg(im), re
return re, im, acc, acc
def evalf_pow(v: 'Pow', prec: int, options) -> TMP_RES:
target_prec = prec
base, exp = v.args
# We handle x**n separately. This has two purposes: 1) it is much
# faster, because we avoid calling evalf on the exponent, and 2) it
# allows better handling of real/imaginary parts that are exactly zero
if exp.is_Integer:
p: int = exp.p # type: ignore
# Exact
if not p:
return fone, None, prec, None
# Exponentiation by p magnifies relative error by |p|, so the
# base must be evaluated with increased precision if p is large
prec += int(math.log2(abs(p)))
result = evalf(base, prec + 5, options)
if result is S.ComplexInfinity:
if p < 0:
return None, None, None, None
return result
re, im, re_acc, im_acc = result
# Real to integer power
if re and not im:
return mpf_pow_int(re, p, target_prec), None, target_prec, None
# (x*I)**n = I**n * x**n
if im and not re:
z = mpf_pow_int(im, p, target_prec)
case = p % 4
if case == 0:
return z, None, target_prec, None
if case == 1:
return None, z, None, target_prec
if case == 2:
return mpf_neg(z), None, target_prec, None
if case == 3:
return None, mpf_neg(z), None, target_prec
# Zero raised to an integer power
if not re:
if p < 0:
return S.ComplexInfinity
return None, None, None, None
# General complex number to arbitrary integer power
re, im = libmp.mpc_pow_int((re, im), p, prec)
# Assumes full accuracy in input
return finalize_complex(re, im, target_prec)
result = evalf(base, prec + 5, options)
if result is S.ComplexInfinity:
if exp.is_Rational:
if exp < 0:
return None, None, None, None
return result
raise NotImplementedError
# Pure square root
if exp is S.Half:
xre, xim, _, _ = result
# General complex square root
if xim:
re, im = libmp.mpc_sqrt((xre or fzero, xim), prec)
return finalize_complex(re, im, prec)
if not xre:
return None, None, None, None
# Square root of a negative real number
if mpf_lt(xre, fzero):
return None, mpf_sqrt(mpf_neg(xre), prec), None, prec
# Positive square root
return mpf_sqrt(xre, prec), None, prec, None
# We first evaluate the exponent to find its magnitude
# This determines the working precision that must be used
prec += 10
result = evalf(exp, prec, options)
if result is S.ComplexInfinity:
return fnan, None, prec, None
yre, yim, _, _ = result
# Special cases: x**0
if not (yre or yim):
return fone, None, prec, None
ysize = fastlog(yre)
# Restart if too big
# XXX: prec + ysize might exceed maxprec
if ysize > 5:
prec += ysize
yre, yim, _, _ = evalf(exp, prec, options)
# Pure exponential function; no need to evalf the base
if base is S.Exp1:
if yim:
re, im = libmp.mpc_exp((yre or fzero, yim), prec)
return finalize_complex(re, im, target_prec)
return mpf_exp(yre, target_prec), None, target_prec, None
xre, xim, _, _ = evalf(base, prec + 5, options)
# 0**y
if not (xre or xim):
if yim:
return fnan, None, prec, None
if yre[0] == 1: # y < 0
return S.ComplexInfinity
return None, None, None, None
# (real ** complex) or (complex ** complex)
if yim:
re, im = libmp.mpc_pow(
(xre or fzero, xim or fzero), (yre or fzero, yim),
target_prec)
return finalize_complex(re, im, target_prec)
# complex ** real
if xim:
re, im = libmp.mpc_pow_mpf((xre or fzero, xim), yre, target_prec)
return finalize_complex(re, im, target_prec)
# negative ** real
elif mpf_lt(xre, fzero):
re, im = libmp.mpc_pow_mpf((xre, fzero), yre, target_prec)
return finalize_complex(re, im, target_prec)
# positive ** real
else:
return mpf_pow(xre, yre, target_prec), None, target_prec, None
#----------------------------------------------------------------------------#
# #
# Special functions #
# #
#----------------------------------------------------------------------------#
def evalf_exp(expr: 'exp', prec: int, options: OPT_DICT) -> TMP_RES:
from .power import Pow
return evalf_pow(Pow(S.Exp1, expr.exp, evaluate=False), prec, options)
def evalf_trig(v: 'Expr', prec: int, options: OPT_DICT) -> TMP_RES:
"""
This function handles sin and cos of complex arguments.
TODO: should also handle tan of complex arguments.
"""
from sympy.functions.elementary.trigonometric import cos, sin
if isinstance(v, cos):
func = mpf_cos
elif isinstance(v, sin):
func = mpf_sin
else:
raise NotImplementedError
arg = v.args[0]
# 20 extra bits is possibly overkill. It does make the need
# to restart very unlikely
xprec = prec + 20
re, im, re_acc, im_acc = evalf(arg, xprec, options)
if im:
if 'subs' in options:
v = v.subs(options['subs'])
return evalf(v._eval_evalf(prec), prec, options)
if not re:
if isinstance(v, cos):
return fone, None, prec, None
elif isinstance(v, sin):
return None, None, None, None
else:
raise NotImplementedError
# For trigonometric functions, we are interested in the
# fixed-point (absolute) accuracy of the argument.
xsize = fastlog(re)
# Magnitude <= 1.0. OK to compute directly, because there is no
# danger of hitting the first root of cos (with sin, magnitude
# <= 2.0 would actually be ok)
if xsize < 1:
return func(re, prec, rnd), None, prec, None
# Very large
if xsize >= 10:
xprec = prec + xsize
re, im, re_acc, im_acc = evalf(arg, xprec, options)
# Need to repeat in case the argument is very close to a
# multiple of pi (or pi/2), hitting close to a root
while 1:
y = func(re, prec, rnd)
ysize = fastlog(y)
gap = -ysize
accuracy = (xprec - xsize) - gap
if accuracy < prec:
if options.get('verbose'):
print("SIN/COS", accuracy, "wanted", prec, "gap", gap)
print(to_str(y, 10))
if xprec > options.get('maxprec', DEFAULT_MAXPREC):
return y, None, accuracy, None
xprec += gap
re, im, re_acc, im_acc = evalf(arg, xprec, options)
continue
else:
return y, None, prec, None
def evalf_log(expr: 'log', prec: int, options: OPT_DICT) -> TMP_RES:
if len(expr.args)>1:
expr = expr.doit()
return evalf(expr, prec, options)
arg = expr.args[0]
workprec = prec + 10
result = evalf(arg, workprec, options)
if result is S.ComplexInfinity:
return result
xre, xim, xacc, _ = result
# evalf can return NoneTypes if chop=True
# issue 18516, 19623
if xre is xim is None:
# Dear reviewer, I do not know what -inf is;
# it looks to be (1, 0, -789, -3)
# but I'm not sure in general,
# so we just let mpmath figure
# it out by taking log of 0 directly.
# It would be better to return -inf instead.
xre = fzero
if xim:
from sympy.functions.elementary.complexes import Abs
from sympy.functions.elementary.exponential import log
# XXX: use get_abs etc instead
re = evalf_log(
log(Abs(arg, evaluate=False), evaluate=False), prec, options)
im = mpf_atan2(xim, xre or fzero, prec)
return re[0], im, re[2], prec
imaginary_term = (mpf_cmp(xre, fzero) < 0)
re = mpf_log(mpf_abs(xre), prec, rnd)
size = fastlog(re)
if prec - size > workprec and re != fzero:
from .add import Add
# We actually need to compute 1+x accurately, not x
add = Add(S.NegativeOne, arg, evaluate=False)
xre, xim, _, _ = evalf_add(add, prec, options)
prec2 = workprec - fastlog(xre)
# xre is now x - 1 so we add 1 back here to calculate x
re = mpf_log(mpf_abs(mpf_add(xre, fone, prec2)), prec, rnd)
re_acc = prec
if imaginary_term:
return re, mpf_pi(prec), re_acc, prec
else:
return re, None, re_acc, None
def evalf_atan(v: 'atan', prec: int, options: OPT_DICT) -> TMP_RES:
arg = v.args[0]
xre, xim, reacc, imacc = evalf(arg, prec + 5, options)
if xre is xim is None:
return (None,)*4
if xim:
raise NotImplementedError
return mpf_atan(xre, prec, rnd), None, prec, None
def evalf_subs(prec: int, subs: dict) -> dict:
""" Change all Float entries in `subs` to have precision prec. """
newsubs = {}
for a, b in subs.items():
b = S(b)
if b.is_Float:
b = b._eval_evalf(prec)
newsubs[a] = b
return newsubs
def evalf_piecewise(expr: 'Expr', prec: int, options: OPT_DICT) -> TMP_RES:
from .numbers import Float, Integer
if 'subs' in options:
expr = expr.subs(evalf_subs(prec, options['subs']))
newopts = options.copy()
del newopts['subs']
if hasattr(expr, 'func'):
return evalf(expr, prec, newopts)
if isinstance(expr, float):
return evalf(Float(expr), prec, newopts)
if isinstance(expr, int):
return evalf(Integer(expr), prec, newopts)
# We still have undefined symbols
raise NotImplementedError
def evalf_alg_num(a: 'AlgebraicNumber', prec: int, options: OPT_DICT) -> TMP_RES:
return evalf(a.to_root(), prec, options)
#----------------------------------------------------------------------------#
# #
# High-level operations #
# #
#----------------------------------------------------------------------------#
def as_mpmath(x: Any, prec: int, options: OPT_DICT) -> tUnion[mpc, mpf]:
from .numbers import Infinity, NegativeInfinity, Zero
x = sympify(x)
if isinstance(x, Zero) or x == 0.0:
return mpf(0)
if isinstance(x, Infinity):
return mpf('inf')
if isinstance(x, NegativeInfinity):
return mpf('-inf')
# XXX
result = evalf(x, prec, options)
return quad_to_mpmath(result)
def do_integral(expr: 'Integral', prec: int, options: OPT_DICT) -> TMP_RES:
func = expr.args[0]
x, xlow, xhigh = expr.args[1]
if xlow == xhigh:
xlow = xhigh = 0
elif x not in func.free_symbols:
# only the difference in limits matters in this case
# so if there is a symbol in common that will cancel
# out when taking the difference, then use that
# difference
if xhigh.free_symbols & xlow.free_symbols:
diff = xhigh - xlow
if diff.is_number:
xlow, xhigh = 0, diff
oldmaxprec = options.get('maxprec', DEFAULT_MAXPREC)
options['maxprec'] = min(oldmaxprec, 2*prec)
with workprec(prec + 5):
xlow = as_mpmath(xlow, prec + 15, options)
xhigh = as_mpmath(xhigh, prec + 15, options)
# Integration is like summation, and we can phone home from
# the integrand function to update accuracy summation style
# Note that this accuracy is inaccurate, since it fails
# to account for the variable quadrature weights,
# but it is better than nothing
from sympy.functions.elementary.trigonometric import cos, sin
from .symbol import Wild
have_part = [False, False]
max_real_term: tUnion[float, int] = MINUS_INF
max_imag_term: tUnion[float, int] = MINUS_INF
def f(t: 'Expr') -> tUnion[mpc, mpf]:
nonlocal max_real_term, max_imag_term
re, im, re_acc, im_acc = evalf(func, mp.prec, {'subs': {x: t}})
have_part[0] = re or have_part[0]
have_part[1] = im or have_part[1]
max_real_term = max(max_real_term, fastlog(re))
max_imag_term = max(max_imag_term, fastlog(im))
if im:
return mpc(re or fzero, im)
return mpf(re or fzero)
if options.get('quad') == 'osc':
A = Wild('A', exclude=[x])
B = Wild('B', exclude=[x])
D = Wild('D')
m = func.match(cos(A*x + B)*D)
if not m:
m = func.match(sin(A*x + B)*D)
if not m:
raise ValueError("An integrand of the form sin(A*x+B)*f(x) "
"or cos(A*x+B)*f(x) is required for oscillatory quadrature")
period = as_mpmath(2*S.Pi/m[A], prec + 15, options)
result = quadosc(f, [xlow, xhigh], period=period)
# XXX: quadosc does not do error detection yet
quadrature_error = MINUS_INF
else:
result, quadrature_err = quadts(f, [xlow, xhigh], error=1)
quadrature_error = fastlog(quadrature_err._mpf_)
options['maxprec'] = oldmaxprec
if have_part[0]:
re: Optional[MPF_TUP] = result.real._mpf_
re_acc: Optional[int]
if re == fzero:
re_s, re_acc = scaled_zero(int(-max(prec, max_real_term, quadrature_error)))
re = scaled_zero(re_s) # handled ok in evalf_integral
else:
re_acc = int(-max(max_real_term - fastlog(re) - prec, quadrature_error))
else:
re, re_acc = None, None
if have_part[1]:
im: Optional[MPF_TUP] = result.imag._mpf_
im_acc: Optional[int]
if im == fzero:
im_s, im_acc = scaled_zero(int(-max(prec, max_imag_term, quadrature_error)))
im = scaled_zero(im_s) # handled ok in evalf_integral
else:
im_acc = int(-max(max_imag_term - fastlog(im) - prec, quadrature_error))
else:
im, im_acc = None, None
result = re, im, re_acc, im_acc
return result
def evalf_integral(expr: 'Integral', prec: int, options: OPT_DICT) -> TMP_RES:
limits = expr.limits
if len(limits) != 1 or len(limits[0]) != 3:
raise NotImplementedError
workprec = prec
i = 0
maxprec = options.get('maxprec', INF)
while 1:
result = do_integral(expr, workprec, options)
accuracy = complex_accuracy(result)
if accuracy >= prec: # achieved desired precision
break
if workprec >= maxprec: # can't increase accuracy any more
break
if accuracy == -1:
# maybe the answer really is zero and maybe we just haven't increased
# the precision enough. So increase by doubling to not take too long
# to get to maxprec.
workprec *= 2
else:
workprec += max(prec, 2**i)
workprec = min(workprec, maxprec)
i += 1
return result
def check_convergence(numer: 'Expr', denom: 'Expr', n: 'Symbol') -> tTuple[int, Any, Any]:
"""
Returns
=======
(h, g, p) where
-- h is:
> 0 for convergence of rate 1/factorial(n)**h
< 0 for divergence of rate factorial(n)**(-h)
= 0 for geometric or polynomial convergence or divergence
-- abs(g) is:
> 1 for geometric convergence of rate 1/h**n
< 1 for geometric divergence of rate h**n
= 1 for polynomial convergence or divergence
(g < 0 indicates an alternating series)
-- p is:
> 1 for polynomial convergence of rate 1/n**h
<= 1 for polynomial divergence of rate n**(-h)
"""
from sympy.polys.polytools import Poly
npol = Poly(numer, n)
dpol = Poly(denom, n)
p = npol.degree()
q = dpol.degree()
rate = q - p
if rate:
return rate, None, None
constant = dpol.LC() / npol.LC()
from .numbers import equal_valued
if not equal_valued(abs(constant), 1):
return rate, constant, None
if npol.degree() == dpol.degree() == 0:
return rate, constant, 0
pc = npol.all_coeffs()[1]
qc = dpol.all_coeffs()[1]
return rate, constant, (qc - pc)/dpol.LC()
def hypsum(expr: 'Expr', n: 'Symbol', start: int, prec: int) -> mpf:
"""
Sum a rapidly convergent infinite hypergeometric series with
given general term, e.g. e = hypsum(1/factorial(n), n). The
quotient between successive terms must be a quotient of integer
polynomials.
"""
from .numbers import Float, equal_valued
from sympy.simplify.simplify import hypersimp
if prec == float('inf'):
raise NotImplementedError('does not support inf prec')
if start:
expr = expr.subs(n, n + start)
hs = hypersimp(expr, n)
if hs is None:
raise NotImplementedError("a hypergeometric series is required")
num, den = hs.as_numer_denom()
func1 = lambdify(n, num)
func2 = lambdify(n, den)
h, g, p = check_convergence(num, den, n)
if h < 0:
raise ValueError("Sum diverges like (n!)^%i" % (-h))
term = expr.subs(n, 0)
if not term.is_Rational:
raise NotImplementedError("Non rational term functionality is not implemented.")
# Direct summation if geometric or faster
if h > 0 or (h == 0 and abs(g) > 1):
term = (MPZ(term.p) << prec) // term.q
s = term
k = 1
while abs(term) > 5:
term *= MPZ(func1(k - 1))
term //= MPZ(func2(k - 1))
s += term
k += 1
return from_man_exp(s, -prec)
else:
alt = g < 0
if abs(g) < 1:
raise ValueError("Sum diverges like (%i)^n" % abs(1/g))
if p < 1 or (equal_valued(p, 1) and not alt):
raise ValueError("Sum diverges like n^%i" % (-p))
# We have polynomial convergence: use Richardson extrapolation
vold = None
ndig = prec_to_dps(prec)
while True:
# Need to use at least quad precision because a lot of cancellation
# might occur in the extrapolation process; we check the answer to
# make sure that the desired precision has been reached, too.
prec2 = 4*prec
term0 = (MPZ(term.p) << prec2) // term.q
def summand(k, _term=[term0]):
if k:
k = int(k)
_term[0] *= MPZ(func1(k - 1))
_term[0] //= MPZ(func2(k - 1))
return make_mpf(from_man_exp(_term[0], -prec2))
with workprec(prec):
v = nsum(summand, [0, mpmath_inf], method='richardson')
vf = Float(v, ndig)
if vold is not None and vold == vf:
break
prec += prec # double precision each time
vold = vf
return v._mpf_
def evalf_prod(expr: 'Product', prec: int, options: OPT_DICT) -> TMP_RES:
if all((l[1] - l[2]).is_Integer for l in expr.limits):
result = evalf(expr.doit(), prec=prec, options=options)
else:
from sympy.concrete.summations import Sum
result = evalf(expr.rewrite(Sum), prec=prec, options=options)
return result
def evalf_sum(expr: 'Sum', prec: int, options: OPT_DICT) -> TMP_RES:
from .numbers import Float
if 'subs' in options:
expr = expr.subs(options['subs'])
func = expr.function
limits = expr.limits
if len(limits) != 1 or len(limits[0]) != 3:
raise NotImplementedError
if func.is_zero:
return None, None, prec, None
prec2 = prec + 10
try:
n, a, b = limits[0]
if b is not S.Infinity or a is S.NegativeInfinity or a != int(a):
raise NotImplementedError
# Use fast hypergeometric summation if possible
v = hypsum(func, n, int(a), prec2)
delta = prec - fastlog(v)
if fastlog(v) < -10:
v = hypsum(func, n, int(a), delta)
return v, None, min(prec, delta), None
except NotImplementedError:
# Euler-Maclaurin summation for general series
eps = Float(2.0)**(-prec)
for i in range(1, 5):
m = n = 2**i * prec
s, err = expr.euler_maclaurin(m=m, n=n, eps=eps,
eval_integral=False)
err = err.evalf()
if err is S.NaN:
raise NotImplementedError
if err <= eps:
break
err = fastlog(evalf(abs(err), 20, options)[0])
re, im, re_acc, im_acc = evalf(s, prec2, options)
if re_acc is None:
re_acc = -err
if im_acc is None:
im_acc = -err
return re, im, re_acc, im_acc
#----------------------------------------------------------------------------#
# #
# Symbolic interface #
# #
#----------------------------------------------------------------------------#
def evalf_symbol(x: 'Expr', prec: int, options: OPT_DICT) -> TMP_RES:
val = options['subs'][x]
if isinstance(val, mpf):
if not val:
return None, None, None, None
return val._mpf_, None, prec, None
else:
if '_cache' not in options:
options['_cache'] = {}
cache = options['_cache']
cached, cached_prec = cache.get(x, (None, MINUS_INF))
if cached_prec >= prec:
return cached
v = evalf(sympify(val), prec, options)
cache[x] = (v, prec)
return v
evalf_table: tDict[Type['Expr'], Callable[['Expr', int, OPT_DICT], TMP_RES]] = {}
def _create_evalf_table():
global evalf_table
from sympy.concrete.products import Product
from sympy.concrete.summations import Sum
from .add import Add
from .mul import Mul
from .numbers import Exp1, Float, Half, ImaginaryUnit, Integer, NaN, NegativeOne, One, Pi, Rational, \
Zero, ComplexInfinity, AlgebraicNumber
from .power import Pow
from .symbol import Dummy, Symbol
from sympy.functions.elementary.complexes import Abs, im, re
from sympy.functions.elementary.exponential import exp, log
from sympy.functions.elementary.integers import ceiling, floor
from sympy.functions.elementary.piecewise import Piecewise
from sympy.functions.elementary.trigonometric import atan, cos, sin
from sympy.integrals.integrals import Integral
evalf_table = {
Symbol: evalf_symbol,
Dummy: evalf_symbol,
Float: evalf_float,
Rational: evalf_rational,
Integer: evalf_integer,
Zero: lambda x, prec, options: (None, None, prec, None),
One: lambda x, prec, options: (fone, None, prec, None),
Half: lambda x, prec, options: (fhalf, None, prec, None),
Pi: lambda x, prec, options: (mpf_pi(prec), None, prec, None),
Exp1: lambda x, prec, options: (mpf_e(prec), None, prec, None),
ImaginaryUnit: lambda x, prec, options: (None, fone, None, prec),
NegativeOne: lambda x, prec, options: (fnone, None, prec, None),
ComplexInfinity: lambda x, prec, options: S.ComplexInfinity,
NaN: lambda x, prec, options: (fnan, None, prec, None),
exp: evalf_exp,
cos: evalf_trig,
sin: evalf_trig,
Add: evalf_add,
Mul: evalf_mul,
Pow: evalf_pow,
log: evalf_log,
atan: evalf_atan,
Abs: evalf_abs,
re: evalf_re,
im: evalf_im,
floor: evalf_floor,
ceiling: evalf_ceiling,
Integral: evalf_integral,
Sum: evalf_sum,
Product: evalf_prod,
Piecewise: evalf_piecewise,
AlgebraicNumber: evalf_alg_num,
}
def evalf(x: 'Expr', prec: int, options: OPT_DICT) -> TMP_RES:
"""
Evaluate the ``Expr`` instance, ``x``
to a binary precision of ``prec``. This
function is supposed to be used internally.
Parameters
==========
x : Expr
The formula to evaluate to a float.
prec : int
The binary precision that the output should have.
options : dict
A dictionary with the same entries as
``EvalfMixin.evalf`` and in addition,
``maxprec`` which is the maximum working precision.
Returns
=======
An optional tuple, ``(re, im, re_acc, im_acc)``
which are the real, imaginary, real accuracy
and imaginary accuracy respectively. ``re`` is
an mpf value tuple and so is ``im``. ``re_acc``
and ``im_acc`` are ints.
NB: all these return values can be ``None``.
If all values are ``None``, then that represents 0.
Note that 0 is also represented as ``fzero = (0, 0, 0, 0)``.
"""
from sympy.functions.elementary.complexes import re as re_, im as im_
try:
rf = evalf_table[type(x)]
r = rf(x, prec, options)
except KeyError:
# Fall back to ordinary evalf if possible
if 'subs' in options:
x = x.subs(evalf_subs(prec, options['subs']))
xe = x._eval_evalf(prec)
if xe is None:
raise NotImplementedError
as_real_imag = getattr(xe, "as_real_imag", None)
if as_real_imag is None:
raise NotImplementedError # e.g. FiniteSet(-1.0, 1.0).evalf()
re, im = as_real_imag()
if re.has(re_) or im.has(im_):
raise NotImplementedError
if not re:
re = None
reprec = None
elif re.is_number:
re = re._to_mpmath(prec, allow_ints=False)._mpf_
reprec = prec
else:
raise NotImplementedError
if not im:
im = None
imprec = None
elif im.is_number:
im = im._to_mpmath(prec, allow_ints=False)._mpf_
imprec = prec
else:
raise NotImplementedError
r = re, im, reprec, imprec
if options.get("verbose"):
print("### input", x)
print("### output", to_str(r[0] or fzero, 50) if isinstance(r, tuple) else r)
print("### raw", r) # r[0], r[2]
print()
chop = options.get('chop', False)
if chop:
if chop is True:
chop_prec = prec
else:
# convert (approximately) from given tolerance;
# the formula here will will make 1e-i rounds to 0 for
# i in the range +/-27 while 2e-i will not be chopped
chop_prec = int(round(-3.321*math.log10(chop) + 2.5))
if chop_prec == 3:
chop_prec -= 1
r = chop_parts(r, chop_prec)
if options.get("strict"):
check_target(x, r, prec)
return r
def quad_to_mpmath(q, ctx=None):
"""Turn the quad returned by ``evalf`` into an ``mpf`` or ``mpc``. """
mpc = make_mpc if ctx is None else ctx.make_mpc
mpf = make_mpf if ctx is None else ctx.make_mpf
if q is S.ComplexInfinity:
raise NotImplementedError
re, im, _, _ = q
if im:
if not re:
re = fzero
return mpc((re, im))
elif re:
return mpf(re)
else:
return mpf(fzero)
class EvalfMixin:
"""Mixin class adding evalf capability."""
__slots__ = () # type: tTuple[str, ...]
def evalf(self, n=15, subs=None, maxn=100, chop=False, strict=False, quad=None, verbose=False):
"""
Evaluate the given formula to an accuracy of *n* digits.
Parameters
==========
subs : dict, optional
Substitute numerical values for symbols, e.g.
``subs={x:3, y:1+pi}``. The substitutions must be given as a
dictionary.
maxn : int, optional
Allow a maximum temporary working precision of maxn digits.
chop : bool or number, optional
Specifies how to replace tiny real or imaginary parts in
subresults by exact zeros.
When ``True`` the chop value defaults to standard precision.
Otherwise the chop value is used to determine the
magnitude of "small" for purposes of chopping.
>>> from sympy import N
>>> x = 1e-4
>>> N(x, chop=True)
0.000100000000000000
>>> N(x, chop=1e-5)
0.000100000000000000
>>> N(x, chop=1e-4)
0
strict : bool, optional
Raise ``PrecisionExhausted`` if any subresult fails to
evaluate to full accuracy, given the available maxprec.
quad : str, optional
Choose algorithm for numerical quadrature. By default,
tanh-sinh quadrature is used. For oscillatory
integrals on an infinite interval, try ``quad='osc'``.
verbose : bool, optional
Print debug information.
Notes
=====
When Floats are naively substituted into an expression,
precision errors may adversely affect the result. For example,
adding 1e16 (a Float) to 1 will truncate to 1e16; if 1e16 is
then subtracted, the result will be 0.
That is exactly what happens in the following:
>>> from sympy.abc import x, y, z
>>> values = {x: 1e16, y: 1, z: 1e16}
>>> (x + y - z).subs(values)
0
Using the subs argument for evalf is the accurate way to
evaluate such an expression:
>>> (x + y - z).evalf(subs=values)
1.00000000000000
"""
from .numbers import Float, Number
n = n if n is not None else 15
if subs and is_sequence(subs):
raise TypeError('subs must be given as a dictionary')
# for sake of sage that doesn't like evalf(1)
if n == 1 and isinstance(self, Number):
from .expr import _mag
rv = self.evalf(2, subs, maxn, chop, strict, quad, verbose)
m = _mag(rv)
rv = rv.round(1 - m)
return rv
if not evalf_table:
_create_evalf_table()
prec = dps_to_prec(n)
options = {'maxprec': max(prec, int(maxn*LG10)), 'chop': chop,
'strict': strict, 'verbose': verbose}
if subs is not None:
options['subs'] = subs
if quad is not None:
options['quad'] = quad
try:
result = evalf(self, prec + 4, options)
except NotImplementedError:
# Fall back to the ordinary evalf
if hasattr(self, 'subs') and subs is not None: # issue 20291
v = self.subs(subs)._eval_evalf(prec)
else:
v = self._eval_evalf(prec)
if v is None:
return self
elif not v.is_number:
return v
try:
# If the result is numerical, normalize it
result = evalf(v, prec, options)
except NotImplementedError:
# Probably contains symbols or unknown functions
return v
if result is S.ComplexInfinity:
return result
re, im, re_acc, im_acc = result
if re is S.NaN or im is S.NaN:
return S.NaN
if re:
p = max(min(prec, re_acc), 1)
re = Float._new(re, p)
else:
re = S.Zero
if im:
p = max(min(prec, im_acc), 1)
im = Float._new(im, p)
return re + im*S.ImaginaryUnit
else:
return re
n = evalf
def _evalf(self, prec):
"""Helper for evalf. Does the same thing but takes binary precision"""
r = self._eval_evalf(prec)
if r is None:
r = self
return r
def _eval_evalf(self, prec):
return
def _to_mpmath(self, prec, allow_ints=True):
# mpmath functions accept ints as input
errmsg = "cannot convert to mpmath number"
if allow_ints and self.is_Integer:
return self.p
if hasattr(self, '_as_mpf_val'):
return make_mpf(self._as_mpf_val(prec))
try:
result = evalf(self, prec, {})
return quad_to_mpmath(result)
except NotImplementedError:
v = self._eval_evalf(prec)
if v is None:
raise ValueError(errmsg)
if v.is_Float:
return make_mpf(v._mpf_)
# Number + Number*I is also fine
re, im = v.as_real_imag()
if allow_ints and re.is_Integer:
re = from_int(re.p)
elif re.is_Float:
re = re._mpf_
else:
raise ValueError(errmsg)
if allow_ints and im.is_Integer:
im = from_int(im.p)
elif im.is_Float:
im = im._mpf_
else:
raise ValueError(errmsg)
return make_mpc((re, im))
def N(x, n=15, **options):
r"""
Calls x.evalf(n, \*\*options).
Explanations
============
Both .n() and N() are equivalent to .evalf(); use the one that you like better.
See also the docstring of .evalf() for information on the options.
Examples
========
>>> from sympy import Sum, oo, N
>>> from sympy.abc import k
>>> Sum(1/k**k, (k, 1, oo))
Sum(k**(-k), (k, 1, oo))
>>> N(_, 4)
1.291
"""
# by using rational=True, any evaluation of a string
# will be done using exact values for the Floats
return sympify(x, rational=True).evalf(n, **options)
def _evalf_with_bounded_error(x: 'Expr', eps: 'Optional[Expr]' = None,
m: int = 0,
options: Optional[OPT_DICT] = None) -> TMP_RES:
"""
Evaluate *x* to within a bounded absolute error.
Parameters
==========
x : Expr
The quantity to be evaluated.
eps : Expr, None, optional (default=None)
Positive real upper bound on the acceptable error.
m : int, optional (default=0)
If *eps* is None, then use 2**(-m) as the upper bound on the error.
options: OPT_DICT
As in the ``evalf`` function.
Returns
=======
A tuple ``(re, im, re_acc, im_acc)``, as returned by ``evalf``.
See Also
========
evalf
"""
if eps is not None:
if not (eps.is_Rational or eps.is_Float) or not eps > 0:
raise ValueError("eps must be positive")
r, _, _, _ = evalf(1/eps, 1, {})
m = fastlog(r)
c, d, _, _ = evalf(x, 1, {})
# Note: If x = a + b*I, then |a| <= 2|c| and |b| <= 2|d|, with equality
# only in the zero case.
# If a is non-zero, then |c| = 2**nc for some integer nc, and c has
# bitcount 1. Therefore 2**fastlog(c) = 2**(nc+1) = 2|c| is an upper bound
# on |a|. Likewise for b and d.
nr, ni = fastlog(c), fastlog(d)
n = max(nr, ni) + 1
# If x is 0, then n is MINUS_INF, and p will be 1. Otherwise,
# n - 1 bits get us past the integer parts of a and b, and +1 accounts for
# the factor of <= sqrt(2) that is |x|/max(|a|, |b|).
p = max(1, m + n + 1)
options = options or {}
return evalf(x, p, options)
PK ]ZZZ�� �g* g* sympy/core/expr.pyfrom __future__ import annotations
from typing import TYPE_CHECKING
from collections.abc import Iterable
from functools import reduce
import re
from .sympify import sympify, _sympify
from .basic import Basic, Atom
from .singleton import S
from .evalf import EvalfMixin, pure_complex, DEFAULT_MAXPREC
from .decorators import call_highest_priority, sympify_method_args, sympify_return
from .cache import cacheit
from .intfunc import mod_inverse
from .sorting import default_sort_key
from .kind import NumberKind
from sympy.utilities.exceptions import sympy_deprecation_warning
from sympy.utilities.misc import as_int, func_name, filldedent
from sympy.utilities.iterables import has_variety, sift
from mpmath.libmp import mpf_log, prec_to_dps
from mpmath.libmp.libintmath import giant_steps
if TYPE_CHECKING:
from .numbers import Number
from collections import defaultdict
def _corem(eq, c): # helper for extract_additively
# return co, diff from co*c + diff
co = []
non = []
for i in Add.make_args(eq):
ci = i.coeff(c)
if not ci:
non.append(i)
else:
co.append(ci)
return Add(*co), Add(*non)
@sympify_method_args
class Expr(Basic, EvalfMixin):
"""
Base class for algebraic expressions.
Explanation
===========
Everything that requires arithmetic operations to be defined
should subclass this class, instead of Basic (which should be
used only for argument storage and expression manipulation, i.e.
pattern matching, substitutions, etc).
If you want to override the comparisons of expressions:
Should use _eval_is_ge for inequality, or _eval_is_eq, with multiple dispatch.
_eval_is_ge return true if x >= y, false if x < y, and None if the two types
are not comparable or the comparison is indeterminate
See Also
========
sympy.core.basic.Basic
"""
__slots__: tuple[str, ...] = ()
is_scalar = True # self derivative is 1
@property
def _diff_wrt(self):
"""Return True if one can differentiate with respect to this
object, else False.
Explanation
===========
Subclasses such as Symbol, Function and Derivative return True
to enable derivatives wrt them. The implementation in Derivative
separates the Symbol and non-Symbol (_diff_wrt=True) variables and
temporarily converts the non-Symbols into Symbols when performing
the differentiation. By default, any object deriving from Expr
will behave like a scalar with self.diff(self) == 1. If this is
not desired then the object must also set `is_scalar = False` or
else define an _eval_derivative routine.
Note, see the docstring of Derivative for how this should work
mathematically. In particular, note that expr.subs(yourclass, Symbol)
should be well-defined on a structural level, or this will lead to
inconsistent results.
Examples
========
>>> from sympy import Expr
>>> e = Expr()
>>> e._diff_wrt
False
>>> class MyScalar(Expr):
... _diff_wrt = True
...
>>> MyScalar().diff(MyScalar())
1
>>> class MySymbol(Expr):
... _diff_wrt = True
... is_scalar = False
...
>>> MySymbol().diff(MySymbol())
Derivative(MySymbol(), MySymbol())
"""
return False
@cacheit
def sort_key(self, order=None):
coeff, expr = self.as_coeff_Mul()
if expr.is_Pow:
if expr.base is S.Exp1:
# If we remove this, many doctests will go crazy:
# (keeps E**x sorted like the exp(x) function,
# part of exp(x) to E**x transition)
expr, exp = Function("exp")(expr.exp), S.One
else:
expr, exp = expr.args
else:
exp = S.One
if expr.is_Dummy:
args = (expr.sort_key(),)
elif expr.is_Atom:
args = (str(expr),)
else:
if expr.is_Add:
args = expr.as_ordered_terms(order=order)
elif expr.is_Mul:
args = expr.as_ordered_factors(order=order)
else:
args = expr.args
args = tuple(
[ default_sort_key(arg, order=order) for arg in args ])
args = (len(args), tuple(args))
exp = exp.sort_key(order=order)
return expr.class_key(), args, exp, coeff
def _hashable_content(self):
"""Return a tuple of information about self that can be used to
compute the hash. If a class defines additional attributes,
like ``name`` in Symbol, then this method should be updated
accordingly to return such relevant attributes.
Defining more than _hashable_content is necessary if __eq__ has
been defined by a class. See note about this in Basic.__eq__."""
return self._args
# ***************
# * Arithmetics *
# ***************
# Expr and its subclasses use _op_priority to determine which object
# passed to a binary special method (__mul__, etc.) will handle the
# operation. In general, the 'call_highest_priority' decorator will choose
# the object with the highest _op_priority to handle the call.
# Custom subclasses that want to define their own binary special methods
# should set an _op_priority value that is higher than the default.
#
# **NOTE**:
# This is a temporary fix, and will eventually be replaced with
# something better and more powerful. See issue 5510.
_op_priority = 10.0
@property
def _add_handler(self):
return Add
@property
def _mul_handler(self):
return Mul
def __pos__(self):
return self
def __neg__(self):
# Mul has its own __neg__ routine, so we just
# create a 2-args Mul with the -1 in the canonical
# slot 0.
c = self.is_commutative
return Mul._from_args((S.NegativeOne, self), c)
def __abs__(self) -> Expr:
from sympy.functions.elementary.complexes import Abs
return Abs(self)
@sympify_return([('other', 'Expr')], NotImplemented)
@call_highest_priority('__radd__')
def __add__(self, other):
return Add(self, other)
@sympify_return([('other', 'Expr')], NotImplemented)
@call_highest_priority('__add__')
def __radd__(self, other):
return Add(other, self)
@sympify_return([('other', 'Expr')], NotImplemented)
@call_highest_priority('__rsub__')
def __sub__(self, other):
return Add(self, -other)
@sympify_return([('other', 'Expr')], NotImplemented)
@call_highest_priority('__sub__')
def __rsub__(self, other):
return Add(other, -self)
@sympify_return([('other', 'Expr')], NotImplemented)
@call_highest_priority('__rmul__')
def __mul__(self, other):
return Mul(self, other)
@sympify_return([('other', 'Expr')], NotImplemented)
@call_highest_priority('__mul__')
def __rmul__(self, other):
return Mul(other, self)
@sympify_return([('other', 'Expr')], NotImplemented)
@call_highest_priority('__rpow__')
def _pow(self, other):
return Pow(self, other)
def __pow__(self, other, mod=None) -> Expr:
if mod is None:
return self._pow(other)
try:
_self, other, mod = as_int(self), as_int(other), as_int(mod)
if other >= 0:
return _sympify(pow(_self, other, mod))
else:
return _sympify(mod_inverse(pow(_self, -other, mod), mod))
except ValueError:
power = self._pow(other)
try:
return power%mod
except TypeError:
return NotImplemented
@sympify_return([('other', 'Expr')], NotImplemented)
@call_highest_priority('__pow__')
def __rpow__(self, other):
return Pow(other, self)
@sympify_return([('other', 'Expr')], NotImplemented)
@call_highest_priority('__rtruediv__')
def __truediv__(self, other):
denom = Pow(other, S.NegativeOne)
if self is S.One:
return denom
else:
return Mul(self, denom)
@sympify_return([('other', 'Expr')], NotImplemented)
@call_highest_priority('__truediv__')
def __rtruediv__(self, other):
denom = Pow(self, S.NegativeOne)
if other is S.One:
return denom
else:
return Mul(other, denom)
@sympify_return([('other', 'Expr')], NotImplemented)
@call_highest_priority('__rmod__')
def __mod__(self, other):
return Mod(self, other)
@sympify_return([('other', 'Expr')], NotImplemented)
@call_highest_priority('__mod__')
def __rmod__(self, other):
return Mod(other, self)
@sympify_return([('other', 'Expr')], NotImplemented)
@call_highest_priority('__rfloordiv__')
def __floordiv__(self, other):
from sympy.functions.elementary.integers import floor
return floor(self / other)
@sympify_return([('other', 'Expr')], NotImplemented)
@call_highest_priority('__floordiv__')
def __rfloordiv__(self, other):
from sympy.functions.elementary.integers import floor
return floor(other / self)
@sympify_return([('other', 'Expr')], NotImplemented)
@call_highest_priority('__rdivmod__')
def __divmod__(self, other):
from sympy.functions.elementary.integers import floor
return floor(self / other), Mod(self, other)
@sympify_return([('other', 'Expr')], NotImplemented)
@call_highest_priority('__divmod__')
def __rdivmod__(self, other):
from sympy.functions.elementary.integers import floor
return floor(other / self), Mod(other, self)
def __int__(self):
if not self.is_number:
raise TypeError("Cannot convert symbols to int")
r = self.round(2)
if not r.is_Number:
raise TypeError("Cannot convert complex to int")
if r in (S.NaN, S.Infinity, S.NegativeInfinity):
raise TypeError("Cannot convert %s to int" % r)
i = int(r)
if not i:
return i
if int_valued(r):
# non-integer self should pass one of these tests
if (self > i) is S.true:
return i
if (self < i) is S.true:
return i - 1
ok = self.equals(i)
if ok is None:
raise TypeError('cannot compute int value accurately')
if ok:
return i
# off by one
return i - (1 if i > 0 else -1)
return i
def __float__(self):
# Don't bother testing if it's a number; if it's not this is going
# to fail, and if it is we still need to check that it evalf'ed to
# a number.
result = self.evalf()
if result.is_Number:
return float(result)
if result.is_number and result.as_real_imag()[1]:
raise TypeError("Cannot convert complex to float")
raise TypeError("Cannot convert expression to float")
def __complex__(self):
result = self.evalf()
re, im = result.as_real_imag()
return complex(float(re), float(im))
@sympify_return([('other', 'Expr')], NotImplemented)
def __ge__(self, other):
from .relational import GreaterThan
return GreaterThan(self, other)
@sympify_return([('other', 'Expr')], NotImplemented)
def __le__(self, other):
from .relational import LessThan
return LessThan(self, other)
@sympify_return([('other', 'Expr')], NotImplemented)
def __gt__(self, other):
from .relational import StrictGreaterThan
return StrictGreaterThan(self, other)
@sympify_return([('other', 'Expr')], NotImplemented)
def __lt__(self, other):
from .relational import StrictLessThan
return StrictLessThan(self, other)
def __trunc__(self):
if not self.is_number:
raise TypeError("Cannot truncate symbols and expressions")
else:
return Integer(self)
def __format__(self, format_spec: str):
if self.is_number:
mt = re.match(r'\+?\d*\.(\d+)f', format_spec)
if mt:
prec = int(mt.group(1))
rounded = self.round(prec)
if rounded.is_Integer:
return format(int(rounded), format_spec)
if rounded.is_Float:
return format(rounded, format_spec)
return super().__format__(format_spec)
@staticmethod
def _from_mpmath(x, prec):
if hasattr(x, "_mpf_"):
return Float._new(x._mpf_, prec)
elif hasattr(x, "_mpc_"):
re, im = x._mpc_
re = Float._new(re, prec)
im = Float._new(im, prec)*S.ImaginaryUnit
return re + im
else:
raise TypeError("expected mpmath number (mpf or mpc)")
@property
def is_number(self):
"""Returns True if ``self`` has no free symbols and no
undefined functions (AppliedUndef, to be precise). It will be
faster than ``if not self.free_symbols``, however, since
``is_number`` will fail as soon as it hits a free symbol
or undefined function.
Examples
========
>>> from sympy import Function, Integral, cos, sin, pi
>>> from sympy.abc import x
>>> f = Function('f')
>>> x.is_number
False
>>> f(1).is_number
False
>>> (2*x).is_number
False
>>> (2 + Integral(2, x)).is_number
False
>>> (2 + Integral(2, (x, 1, 2))).is_number
True
Not all numbers are Numbers in the SymPy sense:
>>> pi.is_number, pi.is_Number
(True, False)
If something is a number it should evaluate to a number with
real and imaginary parts that are Numbers; the result may not
be comparable, however, since the real and/or imaginary part
of the result may not have precision.
>>> cos(1).is_number and cos(1).is_comparable
True
>>> z = cos(1)**2 + sin(1)**2 - 1
>>> z.is_number
True
>>> z.is_comparable
False
See Also
========
sympy.core.basic.Basic.is_comparable
"""
return all(obj.is_number for obj in self.args)
def _random(self, n=None, re_min=-1, im_min=-1, re_max=1, im_max=1):
"""Return self evaluated, if possible, replacing free symbols with
random complex values, if necessary.
Explanation
===========
The random complex value for each free symbol is generated
by the random_complex_number routine giving real and imaginary
parts in the range given by the re_min, re_max, im_min, and im_max
values. The returned value is evaluated to a precision of n
(if given) else the maximum of 15 and the precision needed
to get more than 1 digit of precision. If the expression
could not be evaluated to a number, or could not be evaluated
to more than 1 digit of precision, then None is returned.
Examples
========
>>> from sympy import sqrt
>>> from sympy.abc import x, y
>>> x._random() # doctest: +SKIP
0.0392918155679172 + 0.916050214307199*I
>>> x._random(2) # doctest: +SKIP
-0.77 - 0.87*I
>>> (x + y/2)._random(2) # doctest: +SKIP
-0.57 + 0.16*I
>>> sqrt(2)._random(2)
1.4
See Also
========
sympy.core.random.random_complex_number
"""
free = self.free_symbols
prec = 1
if free:
from sympy.core.random import random_complex_number
a, c, b, d = re_min, re_max, im_min, im_max
reps = dict(list(zip(free, [random_complex_number(a, b, c, d, rational=True)
for zi in free])))
try:
nmag = abs(self.evalf(2, subs=reps))
except (ValueError, TypeError):
# if an out of range value resulted in evalf problems
# then return None -- XXX is there a way to know how to
# select a good random number for a given expression?
# e.g. when calculating n! negative values for n should not
# be used
return None
else:
reps = {}
nmag = abs(self.evalf(2))
if not hasattr(nmag, '_prec'):
# e.g. exp_polar(2*I*pi) doesn't evaluate but is_number is True
return None
if nmag._prec == 1:
# increase the precision up to the default maximum
# precision to see if we can get any significance
# evaluate
for prec in giant_steps(2, DEFAULT_MAXPREC):
nmag = abs(self.evalf(prec, subs=reps))
if nmag._prec != 1:
break
if nmag._prec != 1:
if n is None:
n = max(prec, 15)
return self.evalf(n, subs=reps)
# never got any significance
return None
def is_constant(self, *wrt, **flags):
"""Return True if self is constant, False if not, or None if
the constancy could not be determined conclusively.
Explanation
===========
If an expression has no free symbols then it is a constant. If
there are free symbols it is possible that the expression is a
constant, perhaps (but not necessarily) zero. To test such
expressions, a few strategies are tried:
1) numerical evaluation at two random points. If two such evaluations
give two different values and the values have a precision greater than
1 then self is not constant. If the evaluations agree or could not be
obtained with any precision, no decision is made. The numerical testing
is done only if ``wrt`` is different than the free symbols.
2) differentiation with respect to variables in 'wrt' (or all free
symbols if omitted) to see if the expression is constant or not. This
will not always lead to an expression that is zero even though an
expression is constant (see added test in test_expr.py). If
all derivatives are zero then self is constant with respect to the
given symbols.
3) finding out zeros of denominator expression with free_symbols.
It will not be constant if there are zeros. It gives more negative
answers for expression that are not constant.
If neither evaluation nor differentiation can prove the expression is
constant, None is returned unless two numerical values happened to be
the same and the flag ``failing_number`` is True -- in that case the
numerical value will be returned.
If flag simplify=False is passed, self will not be simplified;
the default is True since self should be simplified before testing.
Examples
========
>>> from sympy import cos, sin, Sum, S, pi
>>> from sympy.abc import a, n, x, y
>>> x.is_constant()
False
>>> S(2).is_constant()
True
>>> Sum(x, (x, 1, 10)).is_constant()
True
>>> Sum(x, (x, 1, n)).is_constant()
False
>>> Sum(x, (x, 1, n)).is_constant(y)
True
>>> Sum(x, (x, 1, n)).is_constant(n)
False
>>> Sum(x, (x, 1, n)).is_constant(x)
True
>>> eq = a*cos(x)**2 + a*sin(x)**2 - a
>>> eq.is_constant()
True
>>> eq.subs({x: pi, a: 2}) == eq.subs({x: pi, a: 3}) == 0
True
>>> (0**x).is_constant()
False
>>> x.is_constant()
False
>>> (x**x).is_constant()
False
>>> one = cos(x)**2 + sin(x)**2
>>> one.is_constant()
True
>>> ((one - 1)**(x + 1)).is_constant() in (True, False) # could be 0 or 1
True
"""
def check_denominator_zeros(expression):
from sympy.solvers.solvers import denoms
retNone = False
for den in denoms(expression):
z = den.is_zero
if z is True:
return True
if z is None:
retNone = True
if retNone:
return None
return False
simplify = flags.get('simplify', True)
if self.is_number:
return True
free = self.free_symbols
if not free:
return True # assume f(1) is some constant
# if we are only interested in some symbols and they are not in the
# free symbols then this expression is constant wrt those symbols
wrt = set(wrt)
if wrt and not wrt & free:
return True
wrt = wrt or free
# simplify unless this has already been done
expr = self
if simplify:
expr = expr.simplify()
# is_zero should be a quick assumptions check; it can be wrong for
# numbers (see test_is_not_constant test), giving False when it
# shouldn't, but hopefully it will never give True unless it is sure.
if expr.is_zero:
return True
# Don't attempt substitution or differentiation with non-number symbols
wrt_number = {sym for sym in wrt if sym.kind is NumberKind}
# try numerical evaluation to see if we get two different values
failing_number = None
if wrt_number == free:
# try 0 (for a) and 1 (for b)
try:
a = expr.subs(list(zip(free, [0]*len(free))),
simultaneous=True)
if a is S.NaN:
# evaluation may succeed when substitution fails
a = expr._random(None, 0, 0, 0, 0)
except ZeroDivisionError:
a = None
if a is not None and a is not S.NaN:
try:
b = expr.subs(list(zip(free, [1]*len(free))),
simultaneous=True)
if b is S.NaN:
# evaluation may succeed when substitution fails
b = expr._random(None, 1, 0, 1, 0)
except ZeroDivisionError:
b = None
if b is not None and b is not S.NaN and b.equals(a) is False:
return False
# try random real
b = expr._random(None, -1, 0, 1, 0)
if b is not None and b is not S.NaN and b.equals(a) is False:
return False
# try random complex
b = expr._random()
if b is not None and b is not S.NaN:
if b.equals(a) is False:
return False
failing_number = a if a.is_number else b
# now we will test each wrt symbol (or all free symbols) to see if the
# expression depends on them or not using differentiation. This is
# not sufficient for all expressions, however, so we don't return
# False if we get a derivative other than 0 with free symbols.
for w in wrt_number:
deriv = expr.diff(w)
if simplify:
deriv = deriv.simplify()
if deriv != 0:
if not (pure_complex(deriv, or_real=True)):
if flags.get('failing_number', False):
return failing_number
return False
cd = check_denominator_zeros(self)
if cd is True:
return False
elif cd is None:
return None
return True
def equals(self, other, failing_expression=False):
"""Return True if self == other, False if it does not, or None. If
failing_expression is True then the expression which did not simplify
to a 0 will be returned instead of None.
Explanation
===========
If ``self`` is a Number (or complex number) that is not zero, then
the result is False.
If ``self`` is a number and has not evaluated to zero, evalf will be
used to test whether the expression evaluates to zero. If it does so
and the result has significance (i.e. the precision is either -1, for
a Rational result, or is greater than 1) then the evalf value will be
used to return True or False.
"""
from sympy.simplify.simplify import nsimplify, simplify
from sympy.solvers.solvers import solve
from sympy.polys.polyerrors import NotAlgebraic
from sympy.polys.numberfields import minimal_polynomial
other = sympify(other)
if self == other:
return True
# they aren't the same so see if we can make the difference 0;
# don't worry about doing simplification steps one at a time
# because if the expression ever goes to 0 then the subsequent
# simplification steps that are done will be very fast.
diff = factor_terms(simplify(self - other), radical=True)
if not diff:
return True
if not diff.has(Add, Mod):
# if there is no expanding to be done after simplifying
# then this can't be a zero
return False
factors = diff.as_coeff_mul()[1]
if len(factors) > 1: # avoid infinity recursion
fac_zero = [fac.equals(0) for fac in factors]
if None not in fac_zero: # every part can be decided
return any(fac_zero)
constant = diff.is_constant(simplify=False, failing_number=True)
if constant is False:
return False
if not diff.is_number:
if constant is None:
# e.g. unless the right simplification is done, a symbolic
# zero is possible (see expression of issue 6829: without
# simplification constant will be None).
return
if constant is True:
# this gives a number whether there are free symbols or not
ndiff = diff._random()
# is_comparable will work whether the result is real
# or complex; it could be None, however.
if ndiff and ndiff.is_comparable:
return False
# sometimes we can use a simplified result to give a clue as to
# what the expression should be; if the expression is *not* zero
# then we should have been able to compute that and so now
# we can just consider the cases where the approximation appears
# to be zero -- we try to prove it via minimal_polynomial.
#
# removed
# ns = nsimplify(diff)
# if diff.is_number and (not ns or ns == diff):
#
# The thought was that if it nsimplifies to 0 that's a sure sign
# to try the following to prove it; or if it changed but wasn't
# zero that might be a sign that it's not going to be easy to
# prove. But tests seem to be working without that logic.
#
if diff.is_number:
# try to prove via self-consistency
surds = [s for s in diff.atoms(Pow) if s.args[0].is_Integer]
# it seems to work better to try big ones first
surds.sort(key=lambda x: -x.args[0])
for s in surds:
try:
# simplify is False here -- this expression has already
# been identified as being hard to identify as zero;
# we will handle the checking ourselves using nsimplify
# to see if we are in the right ballpark or not and if so
# *then* the simplification will be attempted.
sol = solve(diff, s, simplify=False)
if sol:
if s in sol:
# the self-consistent result is present
return True
if all(si.is_Integer for si in sol):
# perfect powers are removed at instantiation
# so surd s cannot be an integer
return False
if all(i.is_algebraic is False for i in sol):
# a surd is algebraic
return False
if any(si in surds for si in sol):
# it wasn't equal to s but it is in surds
# and different surds are not equal
return False
if any(nsimplify(s - si) == 0 and
simplify(s - si) == 0 for si in sol):
return True
if s.is_real:
if any(nsimplify(si, [s]) == s and simplify(si) == s
for si in sol):
return True
except NotImplementedError:
pass
# try to prove with minimal_polynomial but know when
# *not* to use this or else it can take a long time. e.g. issue 8354
if True: # change True to condition that assures non-hang
try:
mp = minimal_polynomial(diff)
if mp.is_Symbol:
return True
return False
except (NotAlgebraic, NotImplementedError):
pass
# diff has not simplified to zero; constant is either None, True
# or the number with significance (is_comparable) that was randomly
# calculated twice as the same value.
if constant not in (True, None) and constant != 0:
return False
if failing_expression:
return diff
return None
def _eval_is_extended_positive_negative(self, positive):
from sympy.polys.numberfields import minimal_polynomial
from sympy.polys.polyerrors import NotAlgebraic
if self.is_number:
# check to see that we can get a value
try:
n2 = self._eval_evalf(2)
# XXX: This shouldn't be caught here
# Catches ValueError: hypsum() failed to converge to the requested
# 34 bits of accuracy
except ValueError:
return None
if n2 is None:
return None
if getattr(n2, '_prec', 1) == 1: # no significance
return None
if n2 is S.NaN:
return None
f = self.evalf(2)
if f.is_Float:
match = f, S.Zero
else:
match = pure_complex(f)
if match is None:
return False
r, i = match
if not (i.is_Number and r.is_Number):
return False
if r._prec != 1 and i._prec != 1:
return bool(not i and ((r > 0) if positive else (r < 0)))
elif r._prec == 1 and (not i or i._prec == 1) and \
self._eval_is_algebraic() and not self.has(Function):
try:
if minimal_polynomial(self).is_Symbol:
return False
except (NotAlgebraic, NotImplementedError):
pass
def _eval_is_extended_positive(self):
return self._eval_is_extended_positive_negative(positive=True)
def _eval_is_extended_negative(self):
return self._eval_is_extended_positive_negative(positive=False)
def _eval_interval(self, x, a, b):
"""
Returns evaluation over an interval. For most functions this is:
self.subs(x, b) - self.subs(x, a),
possibly using limit() if NaN is returned from subs, or if
singularities are found between a and b.
If b or a is None, it only evaluates -self.subs(x, a) or self.subs(b, x),
respectively.
"""
from sympy.calculus.accumulationbounds import AccumBounds
from sympy.functions.elementary.exponential import log
from sympy.series.limits import limit, Limit
from sympy.sets.sets import Interval
from sympy.solvers.solveset import solveset
if (a is None and b is None):
raise ValueError('Both interval ends cannot be None.')
def _eval_endpoint(left):
c = a if left else b
if c is None:
return S.Zero
else:
C = self.subs(x, c)
if C.has(S.NaN, S.Infinity, S.NegativeInfinity,
S.ComplexInfinity, AccumBounds):
if (a < b) != False:
C = limit(self, x, c, "+" if left else "-")
else:
C = limit(self, x, c, "-" if left else "+")
if isinstance(C, Limit):
raise NotImplementedError("Could not compute limit")
return C
if a == b:
return S.Zero
A = _eval_endpoint(left=True)
if A is S.NaN:
return A
B = _eval_endpoint(left=False)
if (a and b) is None:
return B - A
value = B - A
if a.is_comparable and b.is_comparable:
if a < b:
domain = Interval(a, b)
else:
domain = Interval(b, a)
# check the singularities of self within the interval
# if singularities is a ConditionSet (not iterable), catch the exception and pass
singularities = solveset(self.cancel().as_numer_denom()[1], x,
domain=domain)
for logterm in self.atoms(log):
singularities = singularities | solveset(logterm.args[0], x,
domain=domain)
try:
for s in singularities:
if value is S.NaN:
# no need to keep adding, it will stay NaN
break
if not s.is_comparable:
continue
if (a < s) == (s < b) == True:
value += -limit(self, x, s, "+") + limit(self, x, s, "-")
elif (b < s) == (s < a) == True:
value += limit(self, x, s, "+") - limit(self, x, s, "-")
except TypeError:
pass
return value
def _eval_power(self, other):
# subclass to compute self**other for cases when
# other is not NaN, 0, or 1
return None
def _eval_conjugate(self):
if self.is_extended_real:
return self
elif self.is_imaginary:
return -self
def conjugate(self):
"""Returns the complex conjugate of 'self'."""
from sympy.functions.elementary.complexes import conjugate as c
return c(self)
def dir(self, x, cdir):
if self.is_zero:
return S.Zero
from sympy.functions.elementary.exponential import log
minexp = S.Zero
arg = self
while arg:
minexp += S.One
arg = arg.diff(x)
coeff = arg.subs(x, 0)
if coeff is S.NaN:
coeff = arg.limit(x, 0)
if coeff is S.ComplexInfinity:
try:
coeff, _ = arg.leadterm(x)
if coeff.has(log(x)):
raise ValueError()
except ValueError:
coeff = arg.limit(x, 0)
if coeff != S.Zero:
break
return coeff*cdir**minexp
def _eval_transpose(self):
from sympy.functions.elementary.complexes import conjugate
if (self.is_complex or self.is_infinite):
return self
elif self.is_hermitian:
return conjugate(self)
elif self.is_antihermitian:
return -conjugate(self)
def transpose(self):
from sympy.functions.elementary.complexes import transpose
return transpose(self)
def _eval_adjoint(self):
from sympy.functions.elementary.complexes import conjugate, transpose
if self.is_hermitian:
return self
elif self.is_antihermitian:
return -self
obj = self._eval_conjugate()
if obj is not None:
return transpose(obj)
obj = self._eval_transpose()
if obj is not None:
return conjugate(obj)
def adjoint(self):
from sympy.functions.elementary.complexes import adjoint
return adjoint(self)
@classmethod
def _parse_order(cls, order):
"""Parse and configure the ordering of terms. """
from sympy.polys.orderings import monomial_key
startswith = getattr(order, "startswith", None)
if startswith is None:
reverse = False
else:
reverse = startswith('rev-')
if reverse:
order = order[4:]
monom_key = monomial_key(order)
def neg(monom):
return tuple([neg(m) if isinstance(m, tuple) else -m for m in monom])
def key(term):
_, ((re, im), monom, ncpart) = term
monom = neg(monom_key(monom))
ncpart = tuple([e.sort_key(order=order) for e in ncpart])
coeff = ((bool(im), im), (re, im))
return monom, ncpart, coeff
return key, reverse
def as_ordered_factors(self, order=None):
"""Return list of ordered factors (if Mul) else [self]."""
return [self]
def as_poly(self, *gens, **args):
"""Converts ``self`` to a polynomial or returns ``None``.
Explanation
===========
>>> from sympy import sin
>>> from sympy.abc import x, y
>>> print((x**2 + x*y).as_poly())
Poly(x**2 + x*y, x, y, domain='ZZ')
>>> print((x**2 + x*y).as_poly(x, y))
Poly(x**2 + x*y, x, y, domain='ZZ')
>>> print((x**2 + sin(y)).as_poly(x, y))
None
"""
from sympy.polys.polyerrors import PolynomialError, GeneratorsNeeded
from sympy.polys.polytools import Poly
try:
poly = Poly(self, *gens, **args)
if not poly.is_Poly:
return None
else:
return poly
except (PolynomialError, GeneratorsNeeded):
# PolynomialError is caught for e.g. exp(x).as_poly(x)
# GeneratorsNeeded is caught for e.g. S(2).as_poly()
return None
def as_ordered_terms(self, order=None, data=False):
"""
Transform an expression to an ordered list of terms.
Examples
========
>>> from sympy import sin, cos
>>> from sympy.abc import x
>>> (sin(x)**2*cos(x) + sin(x)**2 + 1).as_ordered_terms()
[sin(x)**2*cos(x), sin(x)**2, 1]
"""
from .numbers import Number, NumberSymbol
if order is None and self.is_Add:
# Spot the special case of Add(Number, Mul(Number, expr)) with the
# first number positive and the second number negative
key = lambda x:not isinstance(x, (Number, NumberSymbol))
add_args = sorted(Add.make_args(self), key=key)
if (len(add_args) == 2
and isinstance(add_args[0], (Number, NumberSymbol))
and isinstance(add_args[1], Mul)):
mul_args = sorted(Mul.make_args(add_args[1]), key=key)
if (len(mul_args) == 2
and isinstance(mul_args[0], Number)
and add_args[0].is_positive
and mul_args[0].is_negative):
return add_args
key, reverse = self._parse_order(order)
terms, gens = self.as_terms()
if not any(term.is_Order for term, _ in terms):
ordered = sorted(terms, key=key, reverse=reverse)
else:
_terms, _order = [], []
for term, repr in terms:
if not term.is_Order:
_terms.append((term, repr))
else:
_order.append((term, repr))
ordered = sorted(_terms, key=key, reverse=True) \
+ sorted(_order, key=key, reverse=True)
if data:
return ordered, gens
else:
return [term for term, _ in ordered]
def as_terms(self):
"""Transform an expression to a list of terms. """
from .exprtools import decompose_power
gens, terms = set(), []
for term in Add.make_args(self):
coeff, _term = term.as_coeff_Mul()
coeff = complex(coeff)
cpart, ncpart = {}, []
if _term is not S.One:
for factor in Mul.make_args(_term):
if factor.is_number:
try:
coeff *= complex(factor)
except (TypeError, ValueError):
pass
else:
continue
if factor.is_commutative:
base, exp = decompose_power(factor)
cpart[base] = exp
gens.add(base)
else:
ncpart.append(factor)
coeff = coeff.real, coeff.imag
ncpart = tuple(ncpart)
terms.append((term, (coeff, cpart, ncpart)))
gens = sorted(gens, key=default_sort_key)
k, indices = len(gens), {}
for i, g in enumerate(gens):
indices[g] = i
result = []
for term, (coeff, cpart, ncpart) in terms:
monom = [0]*k
for base, exp in cpart.items():
monom[indices[base]] = exp
result.append((term, (coeff, tuple(monom), ncpart)))
return result, gens
def removeO(self):
"""Removes the additive O(..) symbol if there is one"""
return self
def getO(self):
"""Returns the additive O(..) symbol if there is one, else None."""
return None
def getn(self):
"""
Returns the order of the expression.
Explanation
===========
The order is determined either from the O(...) term. If there
is no O(...) term, it returns None.
Examples
========
>>> from sympy import O
>>> from sympy.abc import x
>>> (1 + x + O(x**2)).getn()
2
>>> (1 + x).getn()
"""
o = self.getO()
if o is None:
return None
elif o.is_Order:
o = o.expr
if o is S.One:
return S.Zero
if o.is_Symbol:
return S.One
if o.is_Pow:
return o.args[1]
if o.is_Mul: # x**n*log(x)**n or x**n/log(x)**n
for oi in o.args:
if oi.is_Symbol:
return S.One
if oi.is_Pow:
from .symbol import Dummy, Symbol
syms = oi.atoms(Symbol)
if len(syms) == 1:
x = syms.pop()
oi = oi.subs(x, Dummy('x', positive=True))
if oi.base.is_Symbol and oi.exp.is_Rational:
return abs(oi.exp)
raise NotImplementedError('not sure of order of %s' % o)
def count_ops(self, visual=None):
from .function import count_ops
return count_ops(self, visual)
def args_cnc(self, cset=False, warn=True, split_1=True):
"""Return [commutative factors, non-commutative factors] of self.
Explanation
===========
self is treated as a Mul and the ordering of the factors is maintained.
If ``cset`` is True the commutative factors will be returned in a set.
If there were repeated factors (as may happen with an unevaluated Mul)
then an error will be raised unless it is explicitly suppressed by
setting ``warn`` to False.
Note: -1 is always separated from a Number unless split_1 is False.
Examples
========
>>> from sympy import symbols, oo
>>> A, B = symbols('A B', commutative=0)
>>> x, y = symbols('x y')
>>> (-2*x*y).args_cnc()
[[-1, 2, x, y], []]
>>> (-2.5*x).args_cnc()
[[-1, 2.5, x], []]
>>> (-2*x*A*B*y).args_cnc()
[[-1, 2, x, y], [A, B]]
>>> (-2*x*A*B*y).args_cnc(split_1=False)
[[-2, x, y], [A, B]]
>>> (-2*x*y).args_cnc(cset=True)
[{-1, 2, x, y}, []]
The arg is always treated as a Mul:
>>> (-2 + x + A).args_cnc()
[[], [x - 2 + A]]
>>> (-oo).args_cnc() # -oo is a singleton
[[-1, oo], []]
"""
if self.is_Mul:
args = list(self.args)
else:
args = [self]
for i, mi in enumerate(args):
if not mi.is_commutative:
c = args[:i]
nc = args[i:]
break
else:
c = args
nc = []
if c and split_1 and (
c[0].is_Number and
c[0].is_extended_negative and
c[0] is not S.NegativeOne):
c[:1] = [S.NegativeOne, -c[0]]
if cset:
clen = len(c)
c = set(c)
if clen and warn and len(c) != clen:
raise ValueError('repeated commutative arguments: %s' %
[ci for ci in c if list(self.args).count(ci) > 1])
return [c, nc]
def coeff(self, x, n=1, right=False, _first=True):
"""
Returns the coefficient from the term(s) containing ``x**n``. If ``n``
is zero then all terms independent of ``x`` will be returned.
Explanation
===========
When ``x`` is noncommutative, the coefficient to the left (default) or
right of ``x`` can be returned. The keyword 'right' is ignored when
``x`` is commutative.
Examples
========
>>> from sympy import symbols
>>> from sympy.abc import x, y, z
You can select terms that have an explicit negative in front of them:
>>> (-x + 2*y).coeff(-1)
x
>>> (x - 2*y).coeff(-1)
2*y
You can select terms with no Rational coefficient:
>>> (x + 2*y).coeff(1)
x
>>> (3 + 2*x + 4*x**2).coeff(1)
0
You can select terms independent of x by making n=0; in this case
expr.as_independent(x)[0] is returned (and 0 will be returned instead
of None):
>>> (3 + 2*x + 4*x**2).coeff(x, 0)
3
>>> eq = ((x + 1)**3).expand() + 1
>>> eq
x**3 + 3*x**2 + 3*x + 2
>>> [eq.coeff(x, i) for i in reversed(range(4))]
[1, 3, 3, 2]
>>> eq -= 2
>>> [eq.coeff(x, i) for i in reversed(range(4))]
[1, 3, 3, 0]
You can select terms that have a numerical term in front of them:
>>> (-x - 2*y).coeff(2)
-y
>>> from sympy import sqrt
>>> (x + sqrt(2)*x).coeff(sqrt(2))
x
The matching is exact:
>>> (3 + 2*x + 4*x**2).coeff(x)
2
>>> (3 + 2*x + 4*x**2).coeff(x**2)
4
>>> (3 + 2*x + 4*x**2).coeff(x**3)
0
>>> (z*(x + y)**2).coeff((x + y)**2)
z
>>> (z*(x + y)**2).coeff(x + y)
0
In addition, no factoring is done, so 1 + z*(1 + y) is not obtained
from the following:
>>> (x + z*(x + x*y)).coeff(x)
1
If such factoring is desired, factor_terms can be used first:
>>> from sympy import factor_terms
>>> factor_terms(x + z*(x + x*y)).coeff(x)
z*(y + 1) + 1
>>> n, m, o = symbols('n m o', commutative=False)
>>> n.coeff(n)
1
>>> (3*n).coeff(n)
3
>>> (n*m + m*n*m).coeff(n) # = (1 + m)*n*m
1 + m
>>> (n*m + m*n*m).coeff(n, right=True) # = (1 + m)*n*m
m
If there is more than one possible coefficient 0 is returned:
>>> (n*m + m*n).coeff(n)
0
If there is only one possible coefficient, it is returned:
>>> (n*m + x*m*n).coeff(m*n)
x
>>> (n*m + x*m*n).coeff(m*n, right=1)
1
See Also
========
as_coefficient: separate the expression into a coefficient and factor
as_coeff_Add: separate the additive constant from an expression
as_coeff_Mul: separate the multiplicative constant from an expression
as_independent: separate x-dependent terms/factors from others
sympy.polys.polytools.Poly.coeff_monomial: efficiently find the single coefficient of a monomial in Poly
sympy.polys.polytools.Poly.nth: like coeff_monomial but powers of monomial terms are used
"""
x = sympify(x)
if not isinstance(x, Basic):
return S.Zero
n = as_int(n)
if not x:
return S.Zero
if x == self:
if n == 1:
return S.One
return S.Zero
if x is S.One:
co = [a for a in Add.make_args(self)
if a.as_coeff_Mul()[0] is S.One]
if not co:
return S.Zero
return Add(*co)
if n == 0:
if x.is_Add and self.is_Add:
c = self.coeff(x, right=right)
if not c:
return S.Zero
if not right:
return self - Add(*[a*x for a in Add.make_args(c)])
return self - Add(*[x*a for a in Add.make_args(c)])
return self.as_independent(x, as_Add=True)[0]
# continue with the full method, looking for this power of x:
x = x**n
def incommon(l1, l2):
if not l1 or not l2:
return []
n = min(len(l1), len(l2))
for i in range(n):
if l1[i] != l2[i]:
return l1[:i]
return l1[:]
def find(l, sub, first=True):
""" Find where list sub appears in list l. When ``first`` is True
the first occurrence from the left is returned, else the last
occurrence is returned. Return None if sub is not in l.
Examples
========
>> l = range(5)*2
>> find(l, [2, 3])
2
>> find(l, [2, 3], first=0)
7
>> find(l, [2, 4])
None
"""
if not sub or not l or len(sub) > len(l):
return None
n = len(sub)
if not first:
l.reverse()
sub.reverse()
for i in range(len(l) - n + 1):
if all(l[i + j] == sub[j] for j in range(n)):
break
else:
i = None
if not first:
l.reverse()
sub.reverse()
if i is not None and not first:
i = len(l) - (i + n)
return i
co = []
args = Add.make_args(self)
self_c = self.is_commutative
x_c = x.is_commutative
if self_c and not x_c:
return S.Zero
if _first and self.is_Add and not self_c and not x_c:
# get the part that depends on x exactly
xargs = Mul.make_args(x)
d = Add(*[i for i in Add.make_args(self.as_independent(x)[1])
if all(xi in Mul.make_args(i) for xi in xargs)])
rv = d.coeff(x, right=right, _first=False)
if not rv.is_Add or not right:
return rv
c_part, nc_part = zip(*[i.args_cnc() for i in rv.args])
if has_variety(c_part):
return rv
return Add(*[Mul._from_args(i) for i in nc_part])
one_c = self_c or x_c
xargs, nx = x.args_cnc(cset=True, warn=bool(not x_c))
# find the parts that pass the commutative terms
for a in args:
margs, nc = a.args_cnc(cset=True, warn=bool(not self_c))
if nc is None:
nc = []
if len(xargs) > len(margs):
continue
resid = margs.difference(xargs)
if len(resid) + len(xargs) == len(margs):
if one_c:
co.append(Mul(*(list(resid) + nc)))
else:
co.append((resid, nc))
if one_c:
if co == []:
return S.Zero
elif co:
return Add(*co)
else: # both nc
# now check the non-comm parts
if not co:
return S.Zero
if all(n == co[0][1] for r, n in co):
ii = find(co[0][1], nx, right)
if ii is not None:
if not right:
return Mul(Add(*[Mul(*r) for r, c in co]), Mul(*co[0][1][:ii]))
else:
return Mul(*co[0][1][ii + len(nx):])
beg = reduce(incommon, (n[1] for n in co))
if beg:
ii = find(beg, nx, right)
if ii is not None:
if not right:
gcdc = co[0][0]
for i in range(1, len(co)):
gcdc = gcdc.intersection(co[i][0])
if not gcdc:
break
return Mul(*(list(gcdc) + beg[:ii]))
else:
m = ii + len(nx)
return Add(*[Mul(*(list(r) + n[m:])) for r, n in co])
end = list(reversed(
reduce(incommon, (list(reversed(n[1])) for n in co))))
if end:
ii = find(end, nx, right)
if ii is not None:
if not right:
return Add(*[Mul(*(list(r) + n[:-len(end) + ii])) for r, n in co])
else:
return Mul(*end[ii + len(nx):])
# look for single match
hit = None
for i, (r, n) in enumerate(co):
ii = find(n, nx, right)
if ii is not None:
if not hit:
hit = ii, r, n
else:
break
else:
if hit:
ii, r, n = hit
if not right:
return Mul(*(list(r) + n[:ii]))
else:
return Mul(*n[ii + len(nx):])
return S.Zero
def as_expr(self, *gens):
"""
Convert a polynomial to a SymPy expression.
Examples
========
>>> from sympy import sin
>>> from sympy.abc import x, y
>>> f = (x**2 + x*y).as_poly(x, y)
>>> f.as_expr()
x**2 + x*y
>>> sin(x).as_expr()
sin(x)
"""
return self
def as_coefficient(self, expr):
"""
Extracts symbolic coefficient at the given expression. In
other words, this functions separates 'self' into the product
of 'expr' and 'expr'-free coefficient. If such separation
is not possible it will return None.
Examples
========
>>> from sympy import E, pi, sin, I, Poly
>>> from sympy.abc import x
>>> E.as_coefficient(E)
1
>>> (2*E).as_coefficient(E)
2
>>> (2*sin(E)*E).as_coefficient(E)
Two terms have E in them so a sum is returned. (If one were
desiring the coefficient of the term exactly matching E then
the constant from the returned expression could be selected.
Or, for greater precision, a method of Poly can be used to
indicate the desired term from which the coefficient is
desired.)
>>> (2*E + x*E).as_coefficient(E)
x + 2
>>> _.args[0] # just want the exact match
2
>>> p = Poly(2*E + x*E); p
Poly(x*E + 2*E, x, E, domain='ZZ')
>>> p.coeff_monomial(E)
2
>>> p.nth(0, 1)
2
Since the following cannot be written as a product containing
E as a factor, None is returned. (If the coefficient ``2*x`` is
desired then the ``coeff`` method should be used.)
>>> (2*E*x + x).as_coefficient(E)
>>> (2*E*x + x).coeff(E)
2*x
>>> (E*(x + 1) + x).as_coefficient(E)
>>> (2*pi*I).as_coefficient(pi*I)
2
>>> (2*I).as_coefficient(pi*I)
See Also
========
coeff: return sum of terms have a given factor
as_coeff_Add: separate the additive constant from an expression
as_coeff_Mul: separate the multiplicative constant from an expression
as_independent: separate x-dependent terms/factors from others
sympy.polys.polytools.Poly.coeff_monomial: efficiently find the single coefficient of a monomial in Poly
sympy.polys.polytools.Poly.nth: like coeff_monomial but powers of monomial terms are used
"""
r = self.extract_multiplicatively(expr)
if r and not r.has(expr):
return r
def as_independent(self, *deps, **hint) -> tuple[Expr, Expr]:
"""
A mostly naive separation of a Mul or Add into arguments that are not
are dependent on deps. To obtain as complete a separation of variables
as possible, use a separation method first, e.g.:
* separatevars() to change Mul, Add and Pow (including exp) into Mul
* .expand(mul=True) to change Add or Mul into Add
* .expand(log=True) to change log expr into an Add
The only non-naive thing that is done here is to respect noncommutative
ordering of variables and to always return (0, 0) for `self` of zero
regardless of hints.
For nonzero `self`, the returned tuple (i, d) has the
following interpretation:
* i will has no variable that appears in deps
* d will either have terms that contain variables that are in deps, or
be equal to 0 (when self is an Add) or 1 (when self is a Mul)
* if self is an Add then self = i + d
* if self is a Mul then self = i*d
* otherwise (self, S.One) or (S.One, self) is returned.
To force the expression to be treated as an Add, use the hint as_Add=True
Examples
========
-- self is an Add
>>> from sympy import sin, cos, exp
>>> from sympy.abc import x, y, z
>>> (x + x*y).as_independent(x)
(0, x*y + x)
>>> (x + x*y).as_independent(y)
(x, x*y)
>>> (2*x*sin(x) + y + x + z).as_independent(x)
(y + z, 2*x*sin(x) + x)
>>> (2*x*sin(x) + y + x + z).as_independent(x, y)
(z, 2*x*sin(x) + x + y)
-- self is a Mul
>>> (x*sin(x)*cos(y)).as_independent(x)
(cos(y), x*sin(x))
non-commutative terms cannot always be separated out when self is a Mul
>>> from sympy import symbols
>>> n1, n2, n3 = symbols('n1 n2 n3', commutative=False)
>>> (n1 + n1*n2).as_independent(n2)
(n1, n1*n2)
>>> (n2*n1 + n1*n2).as_independent(n2)
(0, n1*n2 + n2*n1)
>>> (n1*n2*n3).as_independent(n1)
(1, n1*n2*n3)
>>> (n1*n2*n3).as_independent(n2)
(n1, n2*n3)
>>> ((x-n1)*(x-y)).as_independent(x)
(1, (x - y)*(x - n1))
-- self is anything else:
>>> (sin(x)).as_independent(x)
(1, sin(x))
>>> (sin(x)).as_independent(y)
(sin(x), 1)
>>> exp(x+y).as_independent(x)
(1, exp(x + y))
-- force self to be treated as an Add:
>>> (3*x).as_independent(x, as_Add=True)
(0, 3*x)
-- force self to be treated as a Mul:
>>> (3+x).as_independent(x, as_Add=False)
(1, x + 3)
>>> (-3+x).as_independent(x, as_Add=False)
(1, x - 3)
Note how the below differs from the above in making the
constant on the dep term positive.
>>> (y*(-3+x)).as_independent(x)
(y, x - 3)
-- use .as_independent() for true independence testing instead
of .has(). The former considers only symbols in the free
symbols while the latter considers all symbols
>>> from sympy import Integral
>>> I = Integral(x, (x, 1, 2))
>>> I.has(x)
True
>>> x in I.free_symbols
False
>>> I.as_independent(x) == (I, 1)
True
>>> (I + x).as_independent(x) == (I, x)
True
Note: when trying to get independent terms, a separation method
might need to be used first. In this case, it is important to keep
track of what you send to this routine so you know how to interpret
the returned values
>>> from sympy import separatevars, log
>>> separatevars(exp(x+y)).as_independent(x)
(exp(y), exp(x))
>>> (x + x*y).as_independent(y)
(x, x*y)
>>> separatevars(x + x*y).as_independent(y)
(x, y + 1)
>>> (x*(1 + y)).as_independent(y)
(x, y + 1)
>>> (x*(1 + y)).expand(mul=True).as_independent(y)
(x, x*y)
>>> a, b=symbols('a b', positive=True)
>>> (log(a*b).expand(log=True)).as_independent(b)
(log(a), log(b))
See Also
========
separatevars
expand_log
sympy.core.add.Add.as_two_terms
sympy.core.mul.Mul.as_two_terms
as_coeff_mul
"""
from .symbol import Symbol
from .add import _unevaluated_Add
from .mul import _unevaluated_Mul
if self is S.Zero:
return (self, self)
func = self.func
if hint.get('as_Add', isinstance(self, Add) ):
want = Add
else:
want = Mul
# sift out deps into symbolic and other and ignore
# all symbols but those that are in the free symbols
sym = set()
other = []
for d in deps:
if isinstance(d, Symbol): # Symbol.is_Symbol is True
sym.add(d)
else:
other.append(d)
def has(e):
"""return the standard has() if there are no literal symbols, else
check to see that symbol-deps are in the free symbols."""
has_other = e.has(*other)
if not sym:
return has_other
return has_other or e.has(*(e.free_symbols & sym))
if (want is not func or
func is not Add and func is not Mul):
if has(self):
return (want.identity, self)
else:
return (self, want.identity)
else:
if func is Add:
args = list(self.args)
else:
args, nc = self.args_cnc()
d = sift(args, has)
depend = d[True]
indep = d[False]
if func is Add: # all terms were treated as commutative
return (Add(*indep), _unevaluated_Add(*depend))
else: # handle noncommutative by stopping at first dependent term
for i, n in enumerate(nc):
if has(n):
depend.extend(nc[i:])
break
indep.append(n)
return Mul(*indep), (
Mul(*depend, evaluate=False) if nc else
_unevaluated_Mul(*depend))
def as_real_imag(self, deep=True, **hints):
"""Performs complex expansion on 'self' and returns a tuple
containing collected both real and imaginary parts. This
method cannot be confused with re() and im() functions,
which does not perform complex expansion at evaluation.
However it is possible to expand both re() and im()
functions and get exactly the same results as with
a single call to this function.
>>> from sympy import symbols, I
>>> x, y = symbols('x,y', real=True)
>>> (x + y*I).as_real_imag()
(x, y)
>>> from sympy.abc import z, w
>>> (z + w*I).as_real_imag()
(re(z) - im(w), re(w) + im(z))
"""
if hints.get('ignore') == self:
return None
else:
from sympy.functions.elementary.complexes import im, re
return (re(self), im(self))
def as_powers_dict(self):
"""Return self as a dictionary of factors with each factor being
treated as a power. The keys are the bases of the factors and the
values, the corresponding exponents. The resulting dictionary should
be used with caution if the expression is a Mul and contains non-
commutative factors since the order that they appeared will be lost in
the dictionary.
See Also
========
as_ordered_factors: An alternative for noncommutative applications,
returning an ordered list of factors.
args_cnc: Similar to as_ordered_factors, but guarantees separation
of commutative and noncommutative factors.
"""
d = defaultdict(int)
d.update([self.as_base_exp()])
return d
def as_coefficients_dict(self, *syms):
"""Return a dictionary mapping terms to their Rational coefficient.
Since the dictionary is a defaultdict, inquiries about terms which
were not present will return a coefficient of 0.
If symbols ``syms`` are provided, any multiplicative terms
independent of them will be considered a coefficient and a
regular dictionary of syms-dependent generators as keys and
their corresponding coefficients as values will be returned.
Examples
========
>>> from sympy.abc import a, x, y
>>> (3*x + a*x + 4).as_coefficients_dict()
{1: 4, x: 3, a*x: 1}
>>> _[a]
0
>>> (3*a*x).as_coefficients_dict()
{a*x: 3}
>>> (3*a*x).as_coefficients_dict(x)
{x: 3*a}
>>> (3*a*x).as_coefficients_dict(y)
{1: 3*a*x}
"""
d = defaultdict(list)
if not syms:
for ai in Add.make_args(self):
c, m = ai.as_coeff_Mul()
d[m].append(c)
for k, v in d.items():
if len(v) == 1:
d[k] = v[0]
else:
d[k] = Add(*v)
else:
ind, dep = self.as_independent(*syms, as_Add=True)
for i in Add.make_args(dep):
if i.is_Mul:
c, x = i.as_coeff_mul(*syms)
if c is S.One:
d[i].append(c)
else:
d[i._new_rawargs(*x)].append(c)
elif i:
d[i].append(S.One)
d = {k: Add(*d[k]) for k in d}
if ind is not S.Zero:
d.update({S.One: ind})
di = defaultdict(int)
di.update(d)
return di
def as_base_exp(self) -> tuple[Expr, Expr]:
# a -> b ** e
return self, S.One
def as_coeff_mul(self, *deps, **kwargs) -> tuple[Expr, tuple[Expr, ...]]:
"""Return the tuple (c, args) where self is written as a Mul, ``m``.
c should be a Rational multiplied by any factors of the Mul that are
independent of deps.
args should be a tuple of all other factors of m; args is empty
if self is a Number or if self is independent of deps (when given).
This should be used when you do not know if self is a Mul or not but
you want to treat self as a Mul or if you want to process the
individual arguments of the tail of self as a Mul.
- if you know self is a Mul and want only the head, use self.args[0];
- if you do not want to process the arguments of the tail but need the
tail then use self.as_two_terms() which gives the head and tail;
- if you want to split self into an independent and dependent parts
use ``self.as_independent(*deps)``
>>> from sympy import S
>>> from sympy.abc import x, y
>>> (S(3)).as_coeff_mul()
(3, ())
>>> (3*x*y).as_coeff_mul()
(3, (x, y))
>>> (3*x*y).as_coeff_mul(x)
(3*y, (x,))
>>> (3*y).as_coeff_mul(x)
(3*y, ())
"""
if deps:
if not self.has(*deps):
return self, ()
return S.One, (self,)
def as_coeff_add(self, *deps) -> tuple[Expr, tuple[Expr, ...]]:
"""Return the tuple (c, args) where self is written as an Add, ``a``.
c should be a Rational added to any terms of the Add that are
independent of deps.
args should be a tuple of all other terms of ``a``; args is empty
if self is a Number or if self is independent of deps (when given).
This should be used when you do not know if self is an Add or not but
you want to treat self as an Add or if you want to process the
individual arguments of the tail of self as an Add.
- if you know self is an Add and want only the head, use self.args[0];
- if you do not want to process the arguments of the tail but need the
tail then use self.as_two_terms() which gives the head and tail.
- if you want to split self into an independent and dependent parts
use ``self.as_independent(*deps)``
>>> from sympy import S
>>> from sympy.abc import x, y
>>> (S(3)).as_coeff_add()
(3, ())
>>> (3 + x).as_coeff_add()
(3, (x,))
>>> (3 + x + y).as_coeff_add(x)
(y + 3, (x,))
>>> (3 + y).as_coeff_add(x)
(y + 3, ())
"""
if deps:
if not self.has_free(*deps):
return self, ()
return S.Zero, (self,)
def primitive(self):
"""Return the positive Rational that can be extracted non-recursively
from every term of self (i.e., self is treated like an Add). This is
like the as_coeff_Mul() method but primitive always extracts a positive
Rational (never a negative or a Float).
Examples
========
>>> from sympy.abc import x
>>> (3*(x + 1)**2).primitive()
(3, (x + 1)**2)
>>> a = (6*x + 2); a.primitive()
(2, 3*x + 1)
>>> b = (x/2 + 3); b.primitive()
(1/2, x + 6)
>>> (a*b).primitive() == (1, a*b)
True
"""
if not self:
return S.One, S.Zero
c, r = self.as_coeff_Mul(rational=True)
if c.is_negative:
c, r = -c, -r
return c, r
def as_content_primitive(self, radical=False, clear=True):
"""This method should recursively remove a Rational from all arguments
and return that (content) and the new self (primitive). The content
should always be positive and ``Mul(*foo.as_content_primitive()) == foo``.
The primitive need not be in canonical form and should try to preserve
the underlying structure if possible (i.e. expand_mul should not be
applied to self).
Examples
========
>>> from sympy import sqrt
>>> from sympy.abc import x, y, z
>>> eq = 2 + 2*x + 2*y*(3 + 3*y)
The as_content_primitive function is recursive and retains structure:
>>> eq.as_content_primitive()
(2, x + 3*y*(y + 1) + 1)
Integer powers will have Rationals extracted from the base:
>>> ((2 + 6*x)**2).as_content_primitive()
(4, (3*x + 1)**2)
>>> ((2 + 6*x)**(2*y)).as_content_primitive()
(1, (2*(3*x + 1))**(2*y))
Terms may end up joining once their as_content_primitives are added:
>>> ((5*(x*(1 + y)) + 2*x*(3 + 3*y))).as_content_primitive()
(11, x*(y + 1))
>>> ((3*(x*(1 + y)) + 2*x*(3 + 3*y))).as_content_primitive()
(9, x*(y + 1))
>>> ((3*(z*(1 + y)) + 2.0*x*(3 + 3*y))).as_content_primitive()
(1, 6.0*x*(y + 1) + 3*z*(y + 1))
>>> ((5*(x*(1 + y)) + 2*x*(3 + 3*y))**2).as_content_primitive()
(121, x**2*(y + 1)**2)
>>> ((x*(1 + y) + 0.4*x*(3 + 3*y))**2).as_content_primitive()
(1, 4.84*x**2*(y + 1)**2)
Radical content can also be factored out of the primitive:
>>> (2*sqrt(2) + 4*sqrt(10)).as_content_primitive(radical=True)
(2, sqrt(2)*(1 + 2*sqrt(5)))
If clear=False (default is True) then content will not be removed
from an Add if it can be distributed to leave one or more
terms with integer coefficients.
>>> (x/2 + y).as_content_primitive()
(1/2, x + 2*y)
>>> (x/2 + y).as_content_primitive(clear=False)
(1, x/2 + y)
"""
return S.One, self
def as_numer_denom(self):
"""Return the numerator and the denominator of an expression.
expression -> a/b -> a, b
This is just a stub that should be defined by
an object's class methods to get anything else.
See Also
========
normal: return ``a/b`` instead of ``(a, b)``
"""
return self, S.One
def normal(self):
"""Return the expression as a fraction.
expression -> a/b
See Also
========
as_numer_denom: return ``(a, b)`` instead of ``a/b``
"""
from .mul import _unevaluated_Mul
n, d = self.as_numer_denom()
if d is S.One:
return n
if d.is_Number:
return _unevaluated_Mul(n, 1/d)
else:
return n/d
def extract_multiplicatively(self, c):
"""Return None if it's not possible to make self in the form
c * something in a nice way, i.e. preserving the properties
of arguments of self.
Examples
========
>>> from sympy import symbols, Rational
>>> x, y = symbols('x,y', real=True)
>>> ((x*y)**3).extract_multiplicatively(x**2 * y)
x*y**2
>>> ((x*y)**3).extract_multiplicatively(x**4 * y)
>>> (2*x).extract_multiplicatively(2)
x
>>> (2*x).extract_multiplicatively(3)
>>> (Rational(1, 2)*x).extract_multiplicatively(3)
x/6
"""
from sympy.functions.elementary.exponential import exp
from .add import _unevaluated_Add
c = sympify(c)
if self is S.NaN:
return None
if c is S.One:
return self
elif c == self:
return S.One
if c.is_Add:
cc, pc = c.primitive()
if cc is not S.One:
c = Mul(cc, pc, evaluate=False)
if c.is_Mul:
a, b = c.as_two_terms()
x = self.extract_multiplicatively(a)
if x is not None:
return x.extract_multiplicatively(b)
else:
return x
quotient = self / c
if self.is_Number:
if self is S.Infinity:
if c.is_positive:
return S.Infinity
elif self is S.NegativeInfinity:
if c.is_negative:
return S.Infinity
elif c.is_positive:
return S.NegativeInfinity
elif self is S.ComplexInfinity:
if not c.is_zero:
return S.ComplexInfinity
elif self.is_Integer:
if not quotient.is_Integer:
return None
elif self.is_positive and quotient.is_negative:
return None
else:
return quotient
elif self.is_Rational:
if not quotient.is_Rational:
return None
elif self.is_positive and quotient.is_negative:
return None
else:
return quotient
elif self.is_Float:
if not quotient.is_Float:
return None
elif self.is_positive and quotient.is_negative:
return None
else:
return quotient
elif self.is_NumberSymbol or self.is_Symbol or self is S.ImaginaryUnit:
if quotient.is_Mul and len(quotient.args) == 2:
if quotient.args[0].is_Integer and quotient.args[0].is_positive and quotient.args[1] == self:
return quotient
elif quotient.is_Integer and c.is_Number:
return quotient
elif self.is_Add:
cs, ps = self.primitive()
# assert cs >= 1
if c.is_Number and c is not S.NegativeOne:
# assert c != 1 (handled at top)
if cs is not S.One:
if c.is_negative:
xc = -(cs.extract_multiplicatively(-c))
else:
xc = cs.extract_multiplicatively(c)
if xc is not None:
return xc*ps # rely on 2-arg Mul to restore Add
return # |c| != 1 can only be extracted from cs
if c == ps:
return cs
# check args of ps
newargs = []
for arg in ps.args:
newarg = arg.extract_multiplicatively(c)
if newarg is None:
return # all or nothing
newargs.append(newarg)
if cs is not S.One:
args = [cs*t for t in newargs]
# args may be in different order
return _unevaluated_Add(*args)
else:
return Add._from_args(newargs)
elif self.is_Mul:
args = list(self.args)
for i, arg in enumerate(args):
newarg = arg.extract_multiplicatively(c)
if newarg is not None:
args[i] = newarg
return Mul(*args)
elif self.is_Pow or isinstance(self, exp):
sb, se = self.as_base_exp()
cb, ce = c.as_base_exp()
if cb == sb:
new_exp = se.extract_additively(ce)
if new_exp is not None:
return Pow(sb, new_exp)
elif c == sb:
new_exp = self.exp.extract_additively(1)
if new_exp is not None:
return Pow(sb, new_exp)
def extract_additively(self, c):
"""Return self - c if it's possible to subtract c from self and
make all matching coefficients move towards zero, else return None.
Examples
========
>>> from sympy.abc import x, y
>>> e = 2*x + 3
>>> e.extract_additively(x + 1)
x + 2
>>> e.extract_additively(3*x)
>>> e.extract_additively(4)
>>> (y*(x + 1)).extract_additively(x + 1)
>>> ((x + 1)*(x + 2*y + 1) + 3).extract_additively(x + 1)
(x + 1)*(x + 2*y) + 3
See Also
========
extract_multiplicatively
coeff
as_coefficient
"""
c = sympify(c)
if self is S.NaN:
return None
if c.is_zero:
return self
elif c == self:
return S.Zero
elif self == S.Zero:
return None
if self.is_Number:
if not c.is_Number:
return None
co = self
diff = co - c
# XXX should we match types? i.e should 3 - .1 succeed?
if (co > 0 and diff >= 0 and diff < co or
co < 0 and diff <= 0 and diff > co):
return diff
return None
if c.is_Number:
co, t = self.as_coeff_Add()
xa = co.extract_additively(c)
if xa is None:
return None
return xa + t
# handle the args[0].is_Number case separately
# since we will have trouble looking for the coeff of
# a number.
if c.is_Add and c.args[0].is_Number:
# whole term as a term factor
co = self.coeff(c)
xa0 = (co.extract_additively(1) or 0)*c
if xa0:
diff = self - co*c
return (xa0 + (diff.extract_additively(c) or diff)) or None
# term-wise
h, t = c.as_coeff_Add()
sh, st = self.as_coeff_Add()
xa = sh.extract_additively(h)
if xa is None:
return None
xa2 = st.extract_additively(t)
if xa2 is None:
return None
return xa + xa2
# whole term as a term factor
co, diff = _corem(self, c)
xa0 = (co.extract_additively(1) or 0)*c
if xa0:
return (xa0 + (diff.extract_additively(c) or diff)) or None
# term-wise
coeffs = []
for a in Add.make_args(c):
ac, at = a.as_coeff_Mul()
co = self.coeff(at)
if not co:
return None
coc, cot = co.as_coeff_Add()
xa = coc.extract_additively(ac)
if xa is None:
return None
self -= co*at
coeffs.append((cot + xa)*at)
coeffs.append(self)
return Add(*coeffs)
@property
def expr_free_symbols(self):
"""
Like ``free_symbols``, but returns the free symbols only if
they are contained in an expression node.
Examples
========
>>> from sympy.abc import x, y
>>> (x + y).expr_free_symbols # doctest: +SKIP
{x, y}
If the expression is contained in a non-expression object, do not return
the free symbols. Compare:
>>> from sympy import Tuple
>>> t = Tuple(x + y)
>>> t.expr_free_symbols # doctest: +SKIP
set()
>>> t.free_symbols
{x, y}
"""
sympy_deprecation_warning("""
The expr_free_symbols property is deprecated. Use free_symbols to get
the free symbols of an expression.
""",
deprecated_since_version="1.9",
active_deprecations_target="deprecated-expr-free-symbols")
return {j for i in self.args for j in i.expr_free_symbols}
def could_extract_minus_sign(self):
"""Return True if self has -1 as a leading factor or has
more literal negative signs than positive signs in a sum,
otherwise False.
Examples
========
>>> from sympy.abc import x, y
>>> e = x - y
>>> {i.could_extract_minus_sign() for i in (e, -e)}
{False, True}
Though the ``y - x`` is considered like ``-(x - y)``, since it
is in a product without a leading factor of -1, the result is
false below:
>>> (x*(y - x)).could_extract_minus_sign()
False
To put something in canonical form wrt to sign, use `signsimp`:
>>> from sympy import signsimp
>>> signsimp(x*(y - x))
-x*(x - y)
>>> _.could_extract_minus_sign()
True
"""
return False
def extract_branch_factor(self, allow_half=False):
"""
Try to write self as ``exp_polar(2*pi*I*n)*z`` in a nice way.
Return (z, n).
>>> from sympy import exp_polar, I, pi
>>> from sympy.abc import x, y
>>> exp_polar(I*pi).extract_branch_factor()
(exp_polar(I*pi), 0)
>>> exp_polar(2*I*pi).extract_branch_factor()
(1, 1)
>>> exp_polar(-pi*I).extract_branch_factor()
(exp_polar(I*pi), -1)
>>> exp_polar(3*pi*I + x).extract_branch_factor()
(exp_polar(x + I*pi), 1)
>>> (y*exp_polar(-5*pi*I)*exp_polar(3*pi*I + 2*pi*x)).extract_branch_factor()
(y*exp_polar(2*pi*x), -1)
>>> exp_polar(-I*pi/2).extract_branch_factor()
(exp_polar(-I*pi/2), 0)
If allow_half is True, also extract exp_polar(I*pi):
>>> exp_polar(I*pi).extract_branch_factor(allow_half=True)
(1, 1/2)
>>> exp_polar(2*I*pi).extract_branch_factor(allow_half=True)
(1, 1)
>>> exp_polar(3*I*pi).extract_branch_factor(allow_half=True)
(1, 3/2)
>>> exp_polar(-I*pi).extract_branch_factor(allow_half=True)
(1, -1/2)
"""
from sympy.functions.elementary.exponential import exp_polar
from sympy.functions.elementary.integers import ceiling
n = S.Zero
res = S.One
args = Mul.make_args(self)
exps = []
for arg in args:
if isinstance(arg, exp_polar):
exps += [arg.exp]
else:
res *= arg
piimult = S.Zero
extras = []
ipi = S.Pi*S.ImaginaryUnit
while exps:
exp = exps.pop()
if exp.is_Add:
exps += exp.args
continue
if exp.is_Mul:
coeff = exp.as_coefficient(ipi)
if coeff is not None:
piimult += coeff
continue
extras += [exp]
if piimult.is_number:
coeff = piimult
tail = ()
else:
coeff, tail = piimult.as_coeff_add(*piimult.free_symbols)
# round down to nearest multiple of 2
branchfact = ceiling(coeff/2 - S.Half)*2
n += branchfact/2
c = coeff - branchfact
if allow_half:
nc = c.extract_additively(1)
if nc is not None:
n += S.Half
c = nc
newexp = ipi*Add(*((c, ) + tail)) + Add(*extras)
if newexp != 0:
res *= exp_polar(newexp)
return res, n
def is_polynomial(self, *syms):
r"""
Return True if self is a polynomial in syms and False otherwise.
This checks if self is an exact polynomial in syms. This function
returns False for expressions that are "polynomials" with symbolic
exponents. Thus, you should be able to apply polynomial algorithms to
expressions for which this returns True, and Poly(expr, \*syms) should
work if and only if expr.is_polynomial(\*syms) returns True. The
polynomial does not have to be in expanded form. If no symbols are
given, all free symbols in the expression will be used.
This is not part of the assumptions system. You cannot do
Symbol('z', polynomial=True).
Examples
========
>>> from sympy import Symbol, Function
>>> x = Symbol('x')
>>> ((x**2 + 1)**4).is_polynomial(x)
True
>>> ((x**2 + 1)**4).is_polynomial()
True
>>> (2**x + 1).is_polynomial(x)
False
>>> (2**x + 1).is_polynomial(2**x)
True
>>> f = Function('f')
>>> (f(x) + 1).is_polynomial(x)
False
>>> (f(x) + 1).is_polynomial(f(x))
True
>>> (1/f(x) + 1).is_polynomial(f(x))
False
>>> n = Symbol('n', nonnegative=True, integer=True)
>>> (x**n + 1).is_polynomial(x)
False
This function does not attempt any nontrivial simplifications that may
result in an expression that does not appear to be a polynomial to
become one.
>>> from sympy import sqrt, factor, cancel
>>> y = Symbol('y', positive=True)
>>> a = sqrt(y**2 + 2*y + 1)
>>> a.is_polynomial(y)
False
>>> factor(a)
y + 1
>>> factor(a).is_polynomial(y)
True
>>> b = (y**2 + 2*y + 1)/(y + 1)
>>> b.is_polynomial(y)
False
>>> cancel(b)
y + 1
>>> cancel(b).is_polynomial(y)
True
See also .is_rational_function()
"""
if syms:
syms = set(map(sympify, syms))
else:
syms = self.free_symbols
if not syms:
return True
return self._eval_is_polynomial(syms)
def _eval_is_polynomial(self, syms):
if self in syms:
return True
if not self.has_free(*syms):
# constant polynomial
return True
# subclasses should return True or False
def is_rational_function(self, *syms):
"""
Test whether function is a ratio of two polynomials in the given
symbols, syms. When syms is not given, all free symbols will be used.
The rational function does not have to be in expanded or in any kind of
canonical form.
This function returns False for expressions that are "rational
functions" with symbolic exponents. Thus, you should be able to call
.as_numer_denom() and apply polynomial algorithms to the result for
expressions for which this returns True.
This is not part of the assumptions system. You cannot do
Symbol('z', rational_function=True).
Examples
========
>>> from sympy import Symbol, sin
>>> from sympy.abc import x, y
>>> (x/y).is_rational_function()
True
>>> (x**2).is_rational_function()
True
>>> (x/sin(y)).is_rational_function(y)
False
>>> n = Symbol('n', integer=True)
>>> (x**n + 1).is_rational_function(x)
False
This function does not attempt any nontrivial simplifications that may
result in an expression that does not appear to be a rational function
to become one.
>>> from sympy import sqrt, factor
>>> y = Symbol('y', positive=True)
>>> a = sqrt(y**2 + 2*y + 1)/y
>>> a.is_rational_function(y)
False
>>> factor(a)
(y + 1)/y
>>> factor(a).is_rational_function(y)
True
See also is_algebraic_expr().
"""
if syms:
syms = set(map(sympify, syms))
else:
syms = self.free_symbols
if not syms:
return self not in _illegal
return self._eval_is_rational_function(syms)
def _eval_is_rational_function(self, syms):
if self in syms:
return True
if not self.has_xfree(syms):
return True
# subclasses should return True or False
def is_meromorphic(self, x, a):
"""
This tests whether an expression is meromorphic as
a function of the given symbol ``x`` at the point ``a``.
This method is intended as a quick test that will return
None if no decision can be made without simplification or
more detailed analysis.
Examples
========
>>> from sympy import zoo, log, sin, sqrt
>>> from sympy.abc import x
>>> f = 1/x**2 + 1 - 2*x**3
>>> f.is_meromorphic(x, 0)
True
>>> f.is_meromorphic(x, 1)
True
>>> f.is_meromorphic(x, zoo)
True
>>> g = x**log(3)
>>> g.is_meromorphic(x, 0)
False
>>> g.is_meromorphic(x, 1)
True
>>> g.is_meromorphic(x, zoo)
False
>>> h = sin(1/x)*x**2
>>> h.is_meromorphic(x, 0)
False
>>> h.is_meromorphic(x, 1)
True
>>> h.is_meromorphic(x, zoo)
True
Multivalued functions are considered meromorphic when their
branches are meromorphic. Thus most functions are meromorphic
everywhere except at essential singularities and branch points.
In particular, they will be meromorphic also on branch cuts
except at their endpoints.
>>> log(x).is_meromorphic(x, -1)
True
>>> log(x).is_meromorphic(x, 0)
False
>>> sqrt(x).is_meromorphic(x, -1)
True
>>> sqrt(x).is_meromorphic(x, 0)
False
"""
if not x.is_symbol:
raise TypeError("{} should be of symbol type".format(x))
a = sympify(a)
return self._eval_is_meromorphic(x, a)
def _eval_is_meromorphic(self, x, a):
if self == x:
return True
if not self.has_free(x):
return True
# subclasses should return True or False
def is_algebraic_expr(self, *syms):
"""
This tests whether a given expression is algebraic or not, in the
given symbols, syms. When syms is not given, all free symbols
will be used. The rational function does not have to be in expanded
or in any kind of canonical form.
This function returns False for expressions that are "algebraic
expressions" with symbolic exponents. This is a simple extension to the
is_rational_function, including rational exponentiation.
Examples
========
>>> from sympy import Symbol, sqrt
>>> x = Symbol('x', real=True)
>>> sqrt(1 + x).is_rational_function()
False
>>> sqrt(1 + x).is_algebraic_expr()
True
This function does not attempt any nontrivial simplifications that may
result in an expression that does not appear to be an algebraic
expression to become one.
>>> from sympy import exp, factor
>>> a = sqrt(exp(x)**2 + 2*exp(x) + 1)/(exp(x) + 1)
>>> a.is_algebraic_expr(x)
False
>>> factor(a).is_algebraic_expr()
True
See Also
========
is_rational_function
References
==========
.. [1] https://en.wikipedia.org/wiki/Algebraic_expression
"""
if syms:
syms = set(map(sympify, syms))
else:
syms = self.free_symbols
if not syms:
return True
return self._eval_is_algebraic_expr(syms)
def _eval_is_algebraic_expr(self, syms):
if self in syms:
return True
if not self.has_free(*syms):
return True
# subclasses should return True or False
###################################################################################
##################### SERIES, LEADING TERM, LIMIT, ORDER METHODS ##################
###################################################################################
def series(self, x=None, x0=0, n=6, dir="+", logx=None, cdir=0):
"""
Series expansion of "self" around ``x = x0`` yielding either terms of
the series one by one (the lazy series given when n=None), else
all the terms at once when n != None.
Returns the series expansion of "self" around the point ``x = x0``
with respect to ``x`` up to ``O((x - x0)**n, x, x0)`` (default n is 6).
If ``x=None`` and ``self`` is univariate, the univariate symbol will
be supplied, otherwise an error will be raised.
Parameters
==========
expr : Expression
The expression whose series is to be expanded.
x : Symbol
It is the variable of the expression to be calculated.
x0 : Value
The value around which ``x`` is calculated. Can be any value
from ``-oo`` to ``oo``.
n : Value
The value used to represent the order in terms of ``x**n``,
up to which the series is to be expanded.
dir : String, optional
The series-expansion can be bi-directional. If ``dir="+"``,
then (x->x0+). If ``dir="-", then (x->x0-). For infinite
``x0`` (``oo`` or ``-oo``), the ``dir`` argument is determined
from the direction of the infinity (i.e., ``dir="-"`` for
``oo``).
logx : optional
It is used to replace any log(x) in the returned series with a
symbolic value rather than evaluating the actual value.
cdir : optional
It stands for complex direction, and indicates the direction
from which the expansion needs to be evaluated.
Examples
========
>>> from sympy import cos, exp, tan
>>> from sympy.abc import x, y
>>> cos(x).series()
1 - x**2/2 + x**4/24 + O(x**6)
>>> cos(x).series(n=4)
1 - x**2/2 + O(x**4)
>>> cos(x).series(x, x0=1, n=2)
cos(1) - (x - 1)*sin(1) + O((x - 1)**2, (x, 1))
>>> e = cos(x + exp(y))
>>> e.series(y, n=2)
cos(x + 1) - y*sin(x + 1) + O(y**2)
>>> e.series(x, n=2)
cos(exp(y)) - x*sin(exp(y)) + O(x**2)
If ``n=None`` then a generator of the series terms will be returned.
>>> term=cos(x).series(n=None)
>>> [next(term) for i in range(2)]
[1, -x**2/2]
For ``dir=+`` (default) the series is calculated from the right and
for ``dir=-`` the series from the left. For smooth functions this
flag will not alter the results.
>>> abs(x).series(dir="+")
x
>>> abs(x).series(dir="-")
-x
>>> f = tan(x)
>>> f.series(x, 2, 6, "+")
tan(2) + (1 + tan(2)**2)*(x - 2) + (x - 2)**2*(tan(2)**3 + tan(2)) +
(x - 2)**3*(1/3 + 4*tan(2)**2/3 + tan(2)**4) + (x - 2)**4*(tan(2)**5 +
5*tan(2)**3/3 + 2*tan(2)/3) + (x - 2)**5*(2/15 + 17*tan(2)**2/15 +
2*tan(2)**4 + tan(2)**6) + O((x - 2)**6, (x, 2))
>>> f.series(x, 2, 3, "-")
tan(2) + (2 - x)*(-tan(2)**2 - 1) + (2 - x)**2*(tan(2)**3 + tan(2))
+ O((x - 2)**3, (x, 2))
For rational expressions this method may return original expression without the Order term.
>>> (1/x).series(x, n=8)
1/x
Returns
=======
Expr : Expression
Series expansion of the expression about x0
Raises
======
TypeError
If "n" and "x0" are infinity objects
PoleError
If "x0" is an infinity object
"""
if x is None:
syms = self.free_symbols
if not syms:
return self
elif len(syms) > 1:
raise ValueError('x must be given for multivariate functions.')
x = syms.pop()
from .symbol import Dummy, Symbol
if isinstance(x, Symbol):
dep = x in self.free_symbols
else:
d = Dummy()
dep = d in self.xreplace({x: d}).free_symbols
if not dep:
if n is None:
return (s for s in [self])
else:
return self
if len(dir) != 1 or dir not in '+-':
raise ValueError("Dir must be '+' or '-'")
x0 = sympify(x0)
cdir = sympify(cdir)
from sympy.functions.elementary.complexes import im, sign
if not cdir.is_zero:
if cdir.is_real:
dir = '+' if cdir.is_positive else '-'
else:
dir = '+' if im(cdir).is_positive else '-'
else:
if x0 and x0.is_infinite:
cdir = sign(x0).simplify()
elif str(dir) == "+":
cdir = S.One
elif str(dir) == "-":
cdir = S.NegativeOne
elif cdir == S.Zero:
cdir = S.One
cdir = cdir/abs(cdir)
if x0 and x0.is_infinite:
from .function import PoleError
try:
s = self.subs(x, cdir/x).series(x, n=n, dir='+', cdir=1)
if n is None:
return (si.subs(x, cdir/x) for si in s)
return s.subs(x, cdir/x)
except PoleError:
s = self.subs(x, cdir*x).aseries(x, n=n)
return s.subs(x, cdir*x)
# use rep to shift origin to x0 and change sign (if dir is negative)
# and undo the process with rep2
if x0 or cdir != 1:
s = self.subs({x: x0 + cdir*x}).series(x, x0=0, n=n, dir='+', logx=logx, cdir=1)
if n is None: # lseries...
return (si.subs({x: x/cdir - x0/cdir}) for si in s)
return s.subs({x: x/cdir - x0/cdir})
# from here on it's x0=0 and dir='+' handling
if x.is_positive is x.is_negative is None or x.is_Symbol is not True:
# replace x with an x that has a positive assumption
xpos = Dummy('x', positive=True)
rv = self.subs(x, xpos).series(xpos, x0, n, dir, logx=logx, cdir=cdir)
if n is None:
return (s.subs(xpos, x) for s in rv)
else:
return rv.subs(xpos, x)
from sympy.series.order import Order
if n is not None: # nseries handling
s1 = self._eval_nseries(x, n=n, logx=logx, cdir=cdir)
o = s1.getO() or S.Zero
if o:
# make sure the requested order is returned
ngot = o.getn()
if ngot > n:
# leave o in its current form (e.g. with x*log(x)) so
# it eats terms properly, then replace it below
if n != 0:
s1 += o.subs(x, x**Rational(n, ngot))
else:
s1 += Order(1, x)
elif ngot < n:
# increase the requested number of terms to get the desired
# number keep increasing (up to 9) until the received order
# is different than the original order and then predict how
# many additional terms are needed
from sympy.functions.elementary.integers import ceiling
for more in range(1, 9):
s1 = self._eval_nseries(x, n=n + more, logx=logx, cdir=cdir)
newn = s1.getn()
if newn != ngot:
ndo = n + ceiling((n - ngot)*more/(newn - ngot))
s1 = self._eval_nseries(x, n=ndo, logx=logx, cdir=cdir)
while s1.getn() < n:
s1 = self._eval_nseries(x, n=ndo, logx=logx, cdir=cdir)
ndo += 1
break
else:
raise ValueError('Could not calculate %s terms for %s'
% (str(n), self))
s1 += Order(x**n, x)
o = s1.getO()
s1 = s1.removeO()
elif s1.has(Order):
# asymptotic expansion
return s1
else:
o = Order(x**n, x)
s1done = s1.doit()
try:
if (s1done + o).removeO() == s1done:
o = S.Zero
except NotImplementedError:
return s1
try:
from sympy.simplify.radsimp import collect
return collect(s1, x) + o
except NotImplementedError:
return s1 + o
else: # lseries handling
def yield_lseries(s):
"""Return terms of lseries one at a time."""
for si in s:
if not si.is_Add:
yield si
continue
# yield terms 1 at a time if possible
# by increasing order until all the
# terms have been returned
yielded = 0
o = Order(si, x)*x
ndid = 0
ndo = len(si.args)
while 1:
do = (si - yielded + o).removeO()
o *= x
if not do or do.is_Order:
continue
if do.is_Add:
ndid += len(do.args)
else:
ndid += 1
yield do
if ndid == ndo:
break
yielded += do
return yield_lseries(self.removeO()._eval_lseries(x, logx=logx, cdir=cdir))
def aseries(self, x=None, n=6, bound=0, hir=False):
"""Asymptotic Series expansion of self.
This is equivalent to ``self.series(x, oo, n)``.
Parameters
==========
self : Expression
The expression whose series is to be expanded.
x : Symbol
It is the variable of the expression to be calculated.
n : Value
The value used to represent the order in terms of ``x**n``,
up to which the series is to be expanded.
hir : Boolean
Set this parameter to be True to produce hierarchical series.
It stops the recursion at an early level and may provide nicer
and more useful results.
bound : Value, Integer
Use the ``bound`` parameter to give limit on rewriting
coefficients in its normalised form.
Examples
========
>>> from sympy import sin, exp
>>> from sympy.abc import x
>>> e = sin(1/x + exp(-x)) - sin(1/x)
>>> e.aseries(x)
(1/(24*x**4) - 1/(2*x**2) + 1 + O(x**(-6), (x, oo)))*exp(-x)
>>> e.aseries(x, n=3, hir=True)
-exp(-2*x)*sin(1/x)/2 + exp(-x)*cos(1/x) + O(exp(-3*x), (x, oo))
>>> e = exp(exp(x)/(1 - 1/x))
>>> e.aseries(x)
exp(exp(x)/(1 - 1/x))
>>> e.aseries(x, bound=3) # doctest: +SKIP
exp(exp(x)/x**2)*exp(exp(x)/x)*exp(-exp(x) + exp(x)/(1 - 1/x) - exp(x)/x - exp(x)/x**2)*exp(exp(x))
For rational expressions this method may return original expression without the Order term.
>>> (1/x).aseries(x, n=8)
1/x
Returns
=======
Expr
Asymptotic series expansion of the expression.
Notes
=====
This algorithm is directly induced from the limit computational algorithm provided by Gruntz.
It majorly uses the mrv and rewrite sub-routines. The overall idea of this algorithm is first
to look for the most rapidly varying subexpression w of a given expression f and then expands f
in a series in w. Then same thing is recursively done on the leading coefficient
till we get constant coefficients.
If the most rapidly varying subexpression of a given expression f is f itself,
the algorithm tries to find a normalised representation of the mrv set and rewrites f
using this normalised representation.
If the expansion contains an order term, it will be either ``O(x ** (-n))`` or ``O(w ** (-n))``
where ``w`` belongs to the most rapidly varying expression of ``self``.
References
==========
.. [1] Gruntz, Dominik. A new algorithm for computing asymptotic series.
In: Proc. 1993 Int. Symp. Symbolic and Algebraic Computation. 1993.
pp. 239-244.
.. [2] Gruntz thesis - p90
.. [3] https://en.wikipedia.org/wiki/Asymptotic_expansion
See Also
========
Expr.aseries: See the docstring of this function for complete details of this wrapper.
"""
from .symbol import Dummy
if x.is_positive is x.is_negative is None:
xpos = Dummy('x', positive=True)
return self.subs(x, xpos).aseries(xpos, n, bound, hir).subs(xpos, x)
from .function import PoleError
from sympy.series.gruntz import mrv, rewrite
try:
om, exps = mrv(self, x)
except PoleError:
return self
# We move one level up by replacing `x` by `exp(x)`, and then
# computing the asymptotic series for f(exp(x)). Then asymptotic series
# can be obtained by moving one-step back, by replacing x by ln(x).
from sympy.functions.elementary.exponential import exp, log
from sympy.series.order import Order
if x in om:
s = self.subs(x, exp(x)).aseries(x, n, bound, hir).subs(x, log(x))
if s.getO():
return s + Order(1/x**n, (x, S.Infinity))
return s
k = Dummy('k', positive=True)
# f is rewritten in terms of omega
func, logw = rewrite(exps, om, x, k)
if self in om:
if bound <= 0:
return self
s = (self.exp).aseries(x, n, bound=bound)
s = s.func(*[t.removeO() for t in s.args])
try:
res = exp(s.subs(x, 1/x).as_leading_term(x).subs(x, 1/x))
except PoleError:
res = self
func = exp(self.args[0] - res.args[0]) / k
logw = log(1/res)
s = func.series(k, 0, n)
# Hierarchical series
if hir:
return s.subs(k, exp(logw))
o = s.getO()
terms = sorted(Add.make_args(s.removeO()), key=lambda i: int(i.as_coeff_exponent(k)[1]))
s = S.Zero
has_ord = False
# Then we recursively expand these coefficients one by one into
# their asymptotic series in terms of their most rapidly varying subexpressions.
for t in terms:
coeff, expo = t.as_coeff_exponent(k)
if coeff.has(x):
# Recursive step
snew = coeff.aseries(x, n, bound=bound-1)
if has_ord and snew.getO():
break
elif snew.getO():
has_ord = True
s += (snew * k**expo)
else:
s += t
if not o or has_ord:
return s.subs(k, exp(logw))
return (s + o).subs(k, exp(logw))
def taylor_term(self, n, x, *previous_terms):
"""General method for the taylor term.
This method is slow, because it differentiates n-times. Subclasses can
redefine it to make it faster by using the "previous_terms".
"""
from .symbol import Dummy
from sympy.functions.combinatorial.factorials import factorial
x = sympify(x)
_x = Dummy('x')
return self.subs(x, _x).diff(_x, n).subs(_x, x).subs(x, 0) * x**n / factorial(n)
def lseries(self, x=None, x0=0, dir='+', logx=None, cdir=0):
"""
Wrapper for series yielding an iterator of the terms of the series.
Note: an infinite series will yield an infinite iterator. The following,
for exaxmple, will never terminate. It will just keep printing terms
of the sin(x) series::
for term in sin(x).lseries(x):
print term
The advantage of lseries() over nseries() is that many times you are
just interested in the next term in the series (i.e. the first term for
example), but you do not know how many you should ask for in nseries()
using the "n" parameter.
See also nseries().
"""
return self.series(x, x0, n=None, dir=dir, logx=logx, cdir=cdir)
def _eval_lseries(self, x, logx=None, cdir=0):
# default implementation of lseries is using nseries(), and adaptively
# increasing the "n". As you can see, it is not very efficient, because
# we are calculating the series over and over again. Subclasses should
# override this method and implement much more efficient yielding of
# terms.
n = 0
series = self._eval_nseries(x, n=n, logx=logx, cdir=cdir)
while series.is_Order:
n += 1
series = self._eval_nseries(x, n=n, logx=logx, cdir=cdir)
e = series.removeO()
yield e
if e is S.Zero:
return
while 1:
while 1:
n += 1
series = self._eval_nseries(x, n=n, logx=logx, cdir=cdir).removeO()
if e != series:
break
if (series - self).cancel() is S.Zero:
return
yield series - e
e = series
def nseries(self, x=None, x0=0, n=6, dir='+', logx=None, cdir=0):
"""
Wrapper to _eval_nseries if assumptions allow, else to series.
If x is given, x0 is 0, dir='+', and self has x, then _eval_nseries is
called. This calculates "n" terms in the innermost expressions and
then builds up the final series just by "cross-multiplying" everything
out.
The optional ``logx`` parameter can be used to replace any log(x) in the
returned series with a symbolic value to avoid evaluating log(x) at 0. A
symbol to use in place of log(x) should be provided.
Advantage -- it's fast, because we do not have to determine how many
terms we need to calculate in advance.
Disadvantage -- you may end up with less terms than you may have
expected, but the O(x**n) term appended will always be correct and
so the result, though perhaps shorter, will also be correct.
If any of those assumptions is not met, this is treated like a
wrapper to series which will try harder to return the correct
number of terms.
See also lseries().
Examples
========
>>> from sympy import sin, log, Symbol
>>> from sympy.abc import x, y
>>> sin(x).nseries(x, 0, 6)
x - x**3/6 + x**5/120 + O(x**6)
>>> log(x+1).nseries(x, 0, 5)
x - x**2/2 + x**3/3 - x**4/4 + O(x**5)
Handling of the ``logx`` parameter --- in the following example the
expansion fails since ``sin`` does not have an asymptotic expansion
at -oo (the limit of log(x) as x approaches 0):
>>> e = sin(log(x))
>>> e.nseries(x, 0, 6)
Traceback (most recent call last):
...
PoleError: ...
...
>>> logx = Symbol('logx')
>>> e.nseries(x, 0, 6, logx=logx)
sin(logx)
In the following example, the expansion works but only returns self
unless the ``logx`` parameter is used:
>>> e = x**y
>>> e.nseries(x, 0, 2)
x**y
>>> e.nseries(x, 0, 2, logx=logx)
exp(logx*y)
"""
if x and x not in self.free_symbols:
return self
if x is None or x0 or dir != '+': # {see XPOS above} or (x.is_positive == x.is_negative == None):
return self.series(x, x0, n, dir, cdir=cdir)
else:
return self._eval_nseries(x, n=n, logx=logx, cdir=cdir)
def _eval_nseries(self, x, n, logx, cdir):
"""
Return terms of series for self up to O(x**n) at x=0
from the positive direction.
This is a method that should be overridden in subclasses. Users should
never call this method directly (use .nseries() instead), so you do not
have to write docstrings for _eval_nseries().
"""
raise NotImplementedError(filldedent("""
The _eval_nseries method should be added to
%s to give terms up to O(x**n) at x=0
from the positive direction so it is available when
nseries calls it.""" % self.func)
)
def limit(self, x, xlim, dir='+'):
""" Compute limit x->xlim.
"""
from sympy.series.limits import limit
return limit(self, x, xlim, dir)
def compute_leading_term(self, x, logx=None):
"""Deprecated function to compute the leading term of a series.
as_leading_term is only allowed for results of .series()
This is a wrapper to compute a series first.
"""
from sympy.utilities.exceptions import SymPyDeprecationWarning
SymPyDeprecationWarning(
feature="compute_leading_term",
useinstead="as_leading_term",
issue=21843,
deprecated_since_version="1.12"
).warn()
from sympy.functions.elementary.piecewise import Piecewise, piecewise_fold
if self.has(Piecewise):
expr = piecewise_fold(self)
else:
expr = self
if self.removeO() == 0:
return self
from .symbol import Dummy
from sympy.functions.elementary.exponential import log
from sympy.series.order import Order
_logx = logx
logx = Dummy('logx') if logx is None else logx
res = Order(1)
incr = S.One
while res.is_Order:
res = expr._eval_nseries(x, n=1+incr, logx=logx).cancel().powsimp().trigsimp()
incr *= 2
if _logx is None:
res = res.subs(logx, log(x))
return res.as_leading_term(x)
@cacheit
def as_leading_term(self, *symbols, logx=None, cdir=0):
"""
Returns the leading (nonzero) term of the series expansion of self.
The _eval_as_leading_term routines are used to do this, and they must
always return a non-zero value.
Examples
========
>>> from sympy.abc import x
>>> (1 + x + x**2).as_leading_term(x)
1
>>> (1/x**2 + x + x**2).as_leading_term(x)
x**(-2)
"""
if len(symbols) > 1:
c = self
for x in symbols:
c = c.as_leading_term(x, logx=logx, cdir=cdir)
return c
elif not symbols:
return self
x = sympify(symbols[0])
if not x.is_symbol:
raise ValueError('expecting a Symbol but got %s' % x)
if x not in self.free_symbols:
return self
obj = self._eval_as_leading_term(x, logx=logx, cdir=cdir)
if obj is not None:
from sympy.simplify.powsimp import powsimp
return powsimp(obj, deep=True, combine='exp')
raise NotImplementedError('as_leading_term(%s, %s)' % (self, x))
def _eval_as_leading_term(self, x, logx=None, cdir=0):
return self
def as_coeff_exponent(self, x) -> tuple[Expr, Expr]:
""" ``c*x**e -> c,e`` where x can be any symbolic expression.
"""
from sympy.simplify.radsimp import collect
s = collect(self, x)
c, p = s.as_coeff_mul(x)
if len(p) == 1:
b, e = p[0].as_base_exp()
if b == x:
return c, e
return s, S.Zero
def leadterm(self, x, logx=None, cdir=0):
"""
Returns the leading term a*x**b as a tuple (a, b).
Examples
========
>>> from sympy.abc import x
>>> (1+x+x**2).leadterm(x)
(1, 0)
>>> (1/x**2+x+x**2).leadterm(x)
(1, -2)
"""
from .symbol import Dummy
from sympy.functions.elementary.exponential import log
l = self.as_leading_term(x, logx=logx, cdir=cdir)
d = Dummy('logx')
if l.has(log(x)):
l = l.subs(log(x), d)
c, e = l.as_coeff_exponent(x)
if x in c.free_symbols:
raise ValueError(filldedent("""
cannot compute leadterm(%s, %s). The coefficient
should have been free of %s but got %s""" % (self, x, x, c)))
c = c.subs(d, log(x))
return c, e
def as_coeff_Mul(self, rational: bool = False) -> tuple['Number', Expr]:
"""Efficiently extract the coefficient of a product."""
return S.One, self
def as_coeff_Add(self, rational=False) -> tuple['Number', Expr]:
"""Efficiently extract the coefficient of a summation."""
return S.Zero, self
def fps(self, x=None, x0=0, dir=1, hyper=True, order=4, rational=True,
full=False):
"""
Compute formal power power series of self.
See the docstring of the :func:`fps` function in sympy.series.formal for
more information.
"""
from sympy.series.formal import fps
return fps(self, x, x0, dir, hyper, order, rational, full)
def fourier_series(self, limits=None):
"""Compute fourier sine/cosine series of self.
See the docstring of the :func:`fourier_series` in sympy.series.fourier
for more information.
"""
from sympy.series.fourier import fourier_series
return fourier_series(self, limits)
###################################################################################
##################### DERIVATIVE, INTEGRAL, FUNCTIONAL METHODS ####################
###################################################################################
def diff(self, *symbols, **assumptions):
assumptions.setdefault("evaluate", True)
return _derivative_dispatch(self, *symbols, **assumptions)
###########################################################################
###################### EXPRESSION EXPANSION METHODS #######################
###########################################################################
# Relevant subclasses should override _eval_expand_hint() methods. See
# the docstring of expand() for more info.
def _eval_expand_complex(self, **hints):
real, imag = self.as_real_imag(**hints)
return real + S.ImaginaryUnit*imag
@staticmethod
def _expand_hint(expr, hint, deep=True, **hints):
"""
Helper for ``expand()``. Recursively calls ``expr._eval_expand_hint()``.
Returns ``(expr, hit)``, where expr is the (possibly) expanded
``expr`` and ``hit`` is ``True`` if ``expr`` was truly expanded and
``False`` otherwise.
"""
hit = False
# XXX: Hack to support non-Basic args
# |
# V
if deep and getattr(expr, 'args', ()) and not expr.is_Atom:
sargs = []
for arg in expr.args:
arg, arghit = Expr._expand_hint(arg, hint, **hints)
hit |= arghit
sargs.append(arg)
if hit:
expr = expr.func(*sargs)
if hasattr(expr, hint):
newexpr = getattr(expr, hint)(**hints)
if newexpr != expr:
return (newexpr, True)
return (expr, hit)
@cacheit
def expand(self, deep=True, modulus=None, power_base=True, power_exp=True,
mul=True, log=True, multinomial=True, basic=True, **hints):
"""
Expand an expression using hints.
See the docstring of the expand() function in sympy.core.function for
more information.
"""
from sympy.simplify.radsimp import fraction
hints.update(power_base=power_base, power_exp=power_exp, mul=mul,
log=log, multinomial=multinomial, basic=basic)
expr = self
# default matches fraction's default
_fraction = lambda x: fraction(x, hints.get('exact', False))
if hints.pop('frac', False):
n, d = [a.expand(deep=deep, modulus=modulus, **hints)
for a in _fraction(self)]
return n/d
elif hints.pop('denom', False):
n, d = _fraction(self)
return n/d.expand(deep=deep, modulus=modulus, **hints)
elif hints.pop('numer', False):
n, d = _fraction(self)
return n.expand(deep=deep, modulus=modulus, **hints)/d
# Although the hints are sorted here, an earlier hint may get applied
# at a given node in the expression tree before another because of how
# the hints are applied. e.g. expand(log(x*(y + z))) -> log(x*y +
# x*z) because while applying log at the top level, log and mul are
# applied at the deeper level in the tree so that when the log at the
# upper level gets applied, the mul has already been applied at the
# lower level.
# Additionally, because hints are only applied once, the expression
# may not be expanded all the way. For example, if mul is applied
# before multinomial, x*(x + 1)**2 won't be expanded all the way. For
# now, we just use a special case to make multinomial run before mul,
# so that at least polynomials will be expanded all the way. In the
# future, smarter heuristics should be applied.
# TODO: Smarter heuristics
def _expand_hint_key(hint):
"""Make multinomial come before mul"""
if hint == 'mul':
return 'mulz'
return hint
for hint in sorted(hints.keys(), key=_expand_hint_key):
use_hint = hints[hint]
if use_hint:
hint = '_eval_expand_' + hint
expr, hit = Expr._expand_hint(expr, hint, deep=deep, **hints)
while True:
was = expr
if hints.get('multinomial', False):
expr, _ = Expr._expand_hint(
expr, '_eval_expand_multinomial', deep=deep, **hints)
if hints.get('mul', False):
expr, _ = Expr._expand_hint(
expr, '_eval_expand_mul', deep=deep, **hints)
if hints.get('log', False):
expr, _ = Expr._expand_hint(
expr, '_eval_expand_log', deep=deep, **hints)
if expr == was:
break
if modulus is not None:
modulus = sympify(modulus)
if not modulus.is_Integer or modulus <= 0:
raise ValueError(
"modulus must be a positive integer, got %s" % modulus)
terms = []
for term in Add.make_args(expr):
coeff, tail = term.as_coeff_Mul(rational=True)
coeff %= modulus
if coeff:
terms.append(coeff*tail)
expr = Add(*terms)
return expr
###########################################################################
################### GLOBAL ACTION VERB WRAPPER METHODS ####################
###########################################################################
def integrate(self, *args, **kwargs):
"""See the integrate function in sympy.integrals"""
from sympy.integrals.integrals import integrate
return integrate(self, *args, **kwargs)
def nsimplify(self, constants=(), tolerance=None, full=False):
"""See the nsimplify function in sympy.simplify"""
from sympy.simplify.simplify import nsimplify
return nsimplify(self, constants, tolerance, full)
def separate(self, deep=False, force=False):
"""See the separate function in sympy.simplify"""
from .function import expand_power_base
return expand_power_base(self, deep=deep, force=force)
def collect(self, syms, func=None, evaluate=True, exact=False, distribute_order_term=True):
"""See the collect function in sympy.simplify"""
from sympy.simplify.radsimp import collect
return collect(self, syms, func, evaluate, exact, distribute_order_term)
def together(self, *args, **kwargs):
"""See the together function in sympy.polys"""
from sympy.polys.rationaltools import together
return together(self, *args, **kwargs)
def apart(self, x=None, **args):
"""See the apart function in sympy.polys"""
from sympy.polys.partfrac import apart
return apart(self, x, **args)
def ratsimp(self):
"""See the ratsimp function in sympy.simplify"""
from sympy.simplify.ratsimp import ratsimp
return ratsimp(self)
def trigsimp(self, **args):
"""See the trigsimp function in sympy.simplify"""
from sympy.simplify.trigsimp import trigsimp
return trigsimp(self, **args)
def radsimp(self, **kwargs):
"""See the radsimp function in sympy.simplify"""
from sympy.simplify.radsimp import radsimp
return radsimp(self, **kwargs)
def powsimp(self, *args, **kwargs):
"""See the powsimp function in sympy.simplify"""
from sympy.simplify.powsimp import powsimp
return powsimp(self, *args, **kwargs)
def combsimp(self):
"""See the combsimp function in sympy.simplify"""
from sympy.simplify.combsimp import combsimp
return combsimp(self)
def gammasimp(self):
"""See the gammasimp function in sympy.simplify"""
from sympy.simplify.gammasimp import gammasimp
return gammasimp(self)
def factor(self, *gens, **args):
"""See the factor() function in sympy.polys.polytools"""
from sympy.polys.polytools import factor
return factor(self, *gens, **args)
def cancel(self, *gens, **args):
"""See the cancel function in sympy.polys"""
from sympy.polys.polytools import cancel
return cancel(self, *gens, **args)
def invert(self, g, *gens, **args):
"""Return the multiplicative inverse of ``self`` mod ``g``
where ``self`` (and ``g``) may be symbolic expressions).
See Also
========
sympy.core.intfunc.mod_inverse, sympy.polys.polytools.invert
"""
if self.is_number and getattr(g, 'is_number', True):
return mod_inverse(self, g)
from sympy.polys.polytools import invert
return invert(self, g, *gens, **args)
def round(self, n=None):
"""Return x rounded to the given decimal place.
If a complex number would results, apply round to the real
and imaginary components of the number.
Examples
========
>>> from sympy import pi, E, I, S, Number
>>> pi.round()
3
>>> pi.round(2)
3.14
>>> (2*pi + E*I).round()
6 + 3*I
The round method has a chopping effect:
>>> (2*pi + I/10).round()
6
>>> (pi/10 + 2*I).round()
2*I
>>> (pi/10 + E*I).round(2)
0.31 + 2.72*I
Notes
=====
The Python ``round`` function uses the SymPy ``round`` method so it
will always return a SymPy number (not a Python float or int):
>>> isinstance(round(S(123), -2), Number)
True
"""
x = self
if not x.is_number:
raise TypeError("Cannot round symbolic expression")
if not x.is_Atom:
if not pure_complex(x.n(2), or_real=True):
raise TypeError(
'Expected a number but got %s:' % func_name(x))
elif x in _illegal:
return x
if not (xr := x.is_extended_real):
r, i = x.as_real_imag()
if xr is False:
return r.round(n) + S.ImaginaryUnit*i.round(n)
if i.equals(0):
return r.round(n)
if not x:
return S.Zero if n is None else x
p = as_int(n or 0)
if x.is_Integer:
return Integer(round(int(x), p))
digits_to_decimal = _mag(x) # _mag(12) = 2, _mag(.012) = -1
allow = digits_to_decimal + p
precs = [f._prec for f in x.atoms(Float)]
dps = prec_to_dps(max(precs)) if precs else None
if dps is None:
# assume everything is exact so use the Python
# float default or whatever was requested
dps = max(15, allow)
else:
allow = min(allow, dps)
# this will shift all digits to right of decimal
# and give us dps to work with as an int
shift = -digits_to_decimal + dps
extra = 1 # how far we look past known digits
# NOTE
# mpmath will calculate the binary representation to
# an arbitrary number of digits but we must base our
# answer on a finite number of those digits, e.g.
# .575 2589569785738035/2**52 in binary.
# mpmath shows us that the first 18 digits are
# >>> Float(.575).n(18)
# 0.574999999999999956
# The default precision is 15 digits and if we ask
# for 15 we get
# >>> Float(.575).n(15)
# 0.575000000000000
# mpmath handles rounding at the 15th digit. But we
# need to be careful since the user might be asking
# for rounding at the last digit and our semantics
# are to round toward the even final digit when there
# is a tie. So the extra digit will be used to make
# that decision. In this case, the value is the same
# to 15 digits:
# >>> Float(.575).n(16)
# 0.5750000000000000
# Now converting this to the 15 known digits gives
# 575000000000000.0
# which rounds to integer
# 5750000000000000
# And now we can round to the desired digt, e.g. at
# the second from the left and we get
# 5800000000000000
# and rescaling that gives
# 0.58
# as the final result.
# If the value is made slightly less than 0.575 we might
# still obtain the same value:
# >>> Float(.575-1e-16).n(16)*10**15
# 574999999999999.8
# What 15 digits best represents the known digits (which are
# to the left of the decimal? 5750000000000000, the same as
# before. The only way we will round down (in this case) is
# if we declared that we had more than 15 digits of precision.
# For example, if we use 16 digits of precision, the integer
# we deal with is
# >>> Float(.575-1e-16).n(17)*10**16
# 5749999999999998.4
# and this now rounds to 5749999999999998 and (if we round to
# the 2nd digit from the left) we get 5700000000000000.
#
xf = x.n(dps + extra)*Pow(10, shift)
if xf.is_Number and xf._prec == 1: # xf.is_Add will raise below
# is x == 0?
if x.equals(0):
return Float(0)
raise ValueError('not computing with precision')
xi = Integer(xf)
# use the last digit to select the value of xi
# nearest to x before rounding at the desired digit
sign = 1 if x > 0 else -1
dif2 = sign*(xf - xi).n(extra)
if dif2 < 0:
raise NotImplementedError(
'not expecting int(x) to round away from 0')
if dif2 > .5:
xi += sign # round away from 0
elif dif2 == .5:
xi += sign if xi%2 else -sign # round toward even
# shift p to the new position
ip = p - shift
# let Python handle the int rounding then rescale
xr = round(xi.p, ip)
# restore scale
rv = Rational(xr, Pow(10, shift))
# return Float or Integer
if rv.is_Integer:
if n is None: # the single-arg case
return rv
# use str or else it won't be a float
return Float(str(rv), dps) # keep same precision
else:
if not allow and rv > self:
allow += 1
return Float(rv, allow)
__round__ = round
def _eval_derivative_matrix_lines(self, x):
from sympy.matrices.expressions.matexpr import _LeftRightArgs
return [_LeftRightArgs([S.One, S.One], higher=self._eval_derivative(x))]
class AtomicExpr(Atom, Expr):
"""
A parent class for object which are both atoms and Exprs.
For example: Symbol, Number, Rational, Integer, ...
But not: Add, Mul, Pow, ...
"""
is_number = False
is_Atom = True
__slots__ = ()
def _eval_derivative(self, s):
if self == s:
return S.One
return S.Zero
def _eval_derivative_n_times(self, s, n):
from .containers import Tuple
from sympy.matrices.expressions.matexpr import MatrixExpr
from sympy.matrices.matrixbase import MatrixBase
if isinstance(s, (MatrixBase, Tuple, Iterable, MatrixExpr)):
return super()._eval_derivative_n_times(s, n)
from .relational import Eq
from sympy.functions.elementary.piecewise import Piecewise
if self == s:
return Piecewise((self, Eq(n, 0)), (1, Eq(n, 1)), (0, True))
else:
return Piecewise((self, Eq(n, 0)), (0, True))
def _eval_is_polynomial(self, syms):
return True
def _eval_is_rational_function(self, syms):
return self not in _illegal
def _eval_is_meromorphic(self, x, a):
from sympy.calculus.accumulationbounds import AccumBounds
return (not self.is_Number or self.is_finite) and not isinstance(self, AccumBounds)
def _eval_is_algebraic_expr(self, syms):
return True
def _eval_nseries(self, x, n, logx, cdir=0):
return self
@property
def expr_free_symbols(self):
sympy_deprecation_warning("""
The expr_free_symbols property is deprecated. Use free_symbols to get
the free symbols of an expression.
""",
deprecated_since_version="1.9",
active_deprecations_target="deprecated-expr-free-symbols")
return {self}
def _mag(x):
r"""Return integer $i$ such that $0.1 \le x/10^i < 1$
Examples
========
>>> from sympy.core.expr import _mag
>>> from sympy import Float
>>> _mag(Float(.1))
0
>>> _mag(Float(.01))
-1
>>> _mag(Float(1234))
4
"""
from math import log10, ceil, log
xpos = abs(x.n())
if not xpos:
return S.Zero
try:
mag_first_dig = int(ceil(log10(xpos)))
except (ValueError, OverflowError):
mag_first_dig = int(ceil(Float(mpf_log(xpos._mpf_, 53))/log(10)))
# check that we aren't off by 1
if (xpos/10**mag_first_dig) >= 1:
assert 1 <= (xpos/10**mag_first_dig) < 10
mag_first_dig += 1
return mag_first_dig
class UnevaluatedExpr(Expr):
"""
Expression that is not evaluated unless released.
Examples
========
>>> from sympy import UnevaluatedExpr
>>> from sympy.abc import x
>>> x*(1/x)
1
>>> x*UnevaluatedExpr(1/x)
x*1/x
"""
def __new__(cls, arg, **kwargs):
arg = _sympify(arg)
obj = Expr.__new__(cls, arg, **kwargs)
return obj
def doit(self, **hints):
if hints.get("deep", True):
return self.args[0].doit(**hints)
else:
return self.args[0]
def unchanged(func, *args):
"""Return True if `func` applied to the `args` is unchanged.
Can be used instead of `assert foo == foo`.
Examples
========
>>> from sympy import Piecewise, cos, pi
>>> from sympy.core.expr import unchanged
>>> from sympy.abc import x
>>> unchanged(cos, 1) # instead of assert cos(1) == cos(1)
True
>>> unchanged(cos, pi)
False
Comparison of args uses the builtin capabilities of the object's
arguments to test for equality so args can be defined loosely. Here,
the ExprCondPair arguments of Piecewise compare as equal to the
tuples that can be used to create the Piecewise:
>>> unchanged(Piecewise, (x, x > 1), (0, True))
True
"""
f = func(*args)
return f.func == func and f.args == args
class ExprBuilder:
def __init__(self, op, args=None, validator=None, check=True):
if not hasattr(op, "__call__"):
raise TypeError("op {} needs to be callable".format(op))
self.op = op
if args is None:
self.args = []
else:
self.args = args
self.validator = validator
if (validator is not None) and check:
self.validate()
@staticmethod
def _build_args(args):
return [i.build() if isinstance(i, ExprBuilder) else i for i in args]
def validate(self):
if self.validator is None:
return
args = self._build_args(self.args)
self.validator(*args)
def build(self, check=True):
args = self._build_args(self.args)
if self.validator and check:
self.validator(*args)
return self.op(*args)
def append_argument(self, arg, check=True):
self.args.append(arg)
if self.validator and check:
self.validate(*self.args)
def __getitem__(self, item):
if item == 0:
return self.op
else:
return self.args[item-1]
def __repr__(self):
return str(self.build())
def search_element(self, elem):
for i, arg in enumerate(self.args):
if isinstance(arg, ExprBuilder):
ret = arg.search_index(elem)
if ret is not None:
return (i,) + ret
elif id(arg) == id(elem):
return (i,)
return None
from .mul import Mul
from .add import Add
from .power import Pow
from .function import Function, _derivative_dispatch
from .mod import Mod
from .exprtools import factor_terms
from .numbers import Float, Integer, Rational, _illegal, int_valued
PK ]ZZZvG�o� � sympy/core/exprtools.py"""Tools for manipulating of large commutative expressions. """
from .add import Add
from .mul import Mul, _keep_coeff
from .power import Pow
from .basic import Basic
from .expr import Expr
from .function import expand_power_exp
from .sympify import sympify
from .numbers import Rational, Integer, Number, I, equal_valued
from .singleton import S
from .sorting import default_sort_key, ordered
from .symbol import Dummy
from .traversal import preorder_traversal
from .coreerrors import NonCommutativeExpression
from .containers import Tuple, Dict
from sympy.external.gmpy import SYMPY_INTS
from sympy.utilities.iterables import (common_prefix, common_suffix,
variations, iterable, is_sequence)
from collections import defaultdict
from typing import Tuple as tTuple
_eps = Dummy(positive=True)
def _isnumber(i):
return isinstance(i, (SYMPY_INTS, float)) or i.is_Number
def _monotonic_sign(self):
"""Return the value closest to 0 that ``self`` may have if all symbols
are signed and the result is uniformly the same sign for all values of symbols.
If a symbol is only signed but not known to be an
integer or the result is 0 then a symbol representative of the sign of self
will be returned. Otherwise, None is returned if a) the sign could be positive
or negative or b) self is not in one of the following forms:
- L(x, y, ...) + A: a function linear in all symbols x, y, ... with an
additive constant; if A is zero then the function can be a monomial whose
sign is monotonic over the range of the variables, e.g. (x + 1)**3 if x is
nonnegative.
- A/L(x, y, ...) + B: the inverse of a function linear in all symbols x, y, ...
that does not have a sign change from positive to negative for any set
of values for the variables.
- M(x, y, ...) + A: a monomial M whose factors are all signed and a constant, A.
- A/M(x, y, ...) + B: the inverse of a monomial and constants A and B.
- P(x): a univariate polynomial
Examples
========
>>> from sympy.core.exprtools import _monotonic_sign as F
>>> from sympy import Dummy
>>> nn = Dummy(integer=True, nonnegative=True)
>>> p = Dummy(integer=True, positive=True)
>>> p2 = Dummy(integer=True, positive=True)
>>> F(nn + 1)
1
>>> F(p - 1)
_nneg
>>> F(nn*p + 1)
1
>>> F(p2*p + 1)
2
>>> F(nn - 1) # could be negative, zero or positive
"""
if not self.is_extended_real:
return
if (-self).is_Symbol:
rv = _monotonic_sign(-self)
return rv if rv is None else -rv
if not self.is_Add and self.as_numer_denom()[1].is_number:
s = self
if s.is_prime:
if s.is_odd:
return Integer(3)
else:
return Integer(2)
elif s.is_composite:
if s.is_odd:
return Integer(9)
else:
return Integer(4)
elif s.is_positive:
if s.is_even:
if s.is_prime is False:
return Integer(4)
else:
return Integer(2)
elif s.is_integer:
return S.One
else:
return _eps
elif s.is_extended_negative:
if s.is_even:
return Integer(-2)
elif s.is_integer:
return S.NegativeOne
else:
return -_eps
if s.is_zero or s.is_extended_nonpositive or s.is_extended_nonnegative:
return S.Zero
return None
# univariate polynomial
free = self.free_symbols
if len(free) == 1:
if self.is_polynomial():
from sympy.polys.polytools import real_roots
from sympy.polys.polyroots import roots
from sympy.polys.polyerrors import PolynomialError
x = free.pop()
x0 = _monotonic_sign(x)
if x0 in (_eps, -_eps):
x0 = S.Zero
if x0 is not None:
d = self.diff(x)
if d.is_number:
currentroots = []
else:
try:
currentroots = real_roots(d)
except (PolynomialError, NotImplementedError):
currentroots = [r for r in roots(d, x) if r.is_extended_real]
y = self.subs(x, x0)
if x.is_nonnegative and all(
(r - x0).is_nonpositive for r in currentroots):
if y.is_nonnegative and d.is_positive:
if y:
return y if y.is_positive else Dummy('pos', positive=True)
else:
return Dummy('nneg', nonnegative=True)
if y.is_nonpositive and d.is_negative:
if y:
return y if y.is_negative else Dummy('neg', negative=True)
else:
return Dummy('npos', nonpositive=True)
elif x.is_nonpositive and all(
(r - x0).is_nonnegative for r in currentroots):
if y.is_nonnegative and d.is_negative:
if y:
return Dummy('pos', positive=True)
else:
return Dummy('nneg', nonnegative=True)
if y.is_nonpositive and d.is_positive:
if y:
return Dummy('neg', negative=True)
else:
return Dummy('npos', nonpositive=True)
else:
n, d = self.as_numer_denom()
den = None
if n.is_number:
den = _monotonic_sign(d)
elif not d.is_number:
if _monotonic_sign(n) is not None:
den = _monotonic_sign(d)
if den is not None and (den.is_positive or den.is_negative):
v = n*den
if v.is_positive:
return Dummy('pos', positive=True)
elif v.is_nonnegative:
return Dummy('nneg', nonnegative=True)
elif v.is_negative:
return Dummy('neg', negative=True)
elif v.is_nonpositive:
return Dummy('npos', nonpositive=True)
return None
# multivariate
c, a = self.as_coeff_Add()
v = None
if not a.is_polynomial():
# F/A or A/F where A is a number and F is a signed, rational monomial
n, d = a.as_numer_denom()
if not (n.is_number or d.is_number):
return
if (
a.is_Mul or a.is_Pow) and \
a.is_rational and \
all(p.exp.is_Integer for p in a.atoms(Pow) if p.is_Pow) and \
(a.is_positive or a.is_negative):
v = S.One
for ai in Mul.make_args(a):
if ai.is_number:
v *= ai
continue
reps = {}
for x in ai.free_symbols:
reps[x] = _monotonic_sign(x)
if reps[x] is None:
return
v *= ai.subs(reps)
elif c:
# signed linear expression
if not any(p for p in a.atoms(Pow) if not p.is_number) and (a.is_nonpositive or a.is_nonnegative):
free = list(a.free_symbols)
p = {}
for i in free:
v = _monotonic_sign(i)
if v is None:
return
p[i] = v or (_eps if i.is_nonnegative else -_eps)
v = a.xreplace(p)
if v is not None:
rv = v + c
if v.is_nonnegative and rv.is_positive:
return rv.subs(_eps, 0)
if v.is_nonpositive and rv.is_negative:
return rv.subs(_eps, 0)
def decompose_power(expr: Expr) -> tTuple[Expr, int]:
"""
Decompose power into symbolic base and integer exponent.
Examples
========
>>> from sympy.core.exprtools import decompose_power
>>> from sympy.abc import x, y
>>> from sympy import exp
>>> decompose_power(x)
(x, 1)
>>> decompose_power(x**2)
(x, 2)
>>> decompose_power(exp(2*y/3))
(exp(y/3), 2)
"""
base, exp = expr.as_base_exp()
if exp.is_Number:
if exp.is_Rational:
if not exp.is_Integer:
base = Pow(base, Rational(1, exp.q)) # type: ignore
e = exp.p # type: ignore
else:
base, e = expr, 1
else:
exp, tail = exp.as_coeff_Mul(rational=True)
if exp is S.NegativeOne:
base, e = Pow(base, tail), -1
elif exp is not S.One:
# todo: after dropping python 3.7 support, use overload and Literal
# in as_coeff_Mul to make exp Rational, and remove these 2 ignores
tail = _keep_coeff(Rational(1, exp.q), tail) # type: ignore
base, e = Pow(base, tail), exp.p # type: ignore
else:
base, e = expr, 1
return base, e
def decompose_power_rat(expr: Expr) -> tTuple[Expr, Rational]:
"""
Decompose power into symbolic base and rational exponent;
if the exponent is not a Rational, then separate only the
integer coefficient.
Examples
========
>>> from sympy.core.exprtools import decompose_power_rat
>>> from sympy.abc import x
>>> from sympy import sqrt, exp
>>> decompose_power_rat(sqrt(x))
(x, 1/2)
>>> decompose_power_rat(exp(-3*x/2))
(exp(x/2), -3)
"""
_ = base, exp = expr.as_base_exp()
return _ if exp.is_Rational else decompose_power(expr)
class Factors:
"""Efficient representation of ``f_1*f_2*...*f_n``."""
__slots__ = ('factors', 'gens')
def __init__(self, factors=None): # Factors
"""Initialize Factors from dict or expr.
Examples
========
>>> from sympy.core.exprtools import Factors
>>> from sympy.abc import x
>>> from sympy import I
>>> e = 2*x**3
>>> Factors(e)
Factors({2: 1, x: 3})
>>> Factors(e.as_powers_dict())
Factors({2: 1, x: 3})
>>> f = _
>>> f.factors # underlying dictionary
{2: 1, x: 3}
>>> f.gens # base of each factor
frozenset({2, x})
>>> Factors(0)
Factors({0: 1})
>>> Factors(I)
Factors({I: 1})
Notes
=====
Although a dictionary can be passed, only minimal checking is
performed: powers of -1 and I are made canonical.
"""
if isinstance(factors, (SYMPY_INTS, float)):
factors = S(factors)
if isinstance(factors, Factors):
factors = factors.factors.copy()
elif factors in (None, S.One):
factors = {}
elif factors is S.Zero or factors == 0:
factors = {S.Zero: S.One}
elif isinstance(factors, Number):
n = factors
factors = {}
if n < 0:
factors[S.NegativeOne] = S.One
n = -n
if n is not S.One:
if n.is_Float or n.is_Integer or n is S.Infinity:
factors[n] = S.One
elif n.is_Rational:
# since we're processing Numbers, the denominator is
# stored with a negative exponent; all other factors
# are left .
if n.p != 1:
factors[Integer(n.p)] = S.One
factors[Integer(n.q)] = S.NegativeOne
else:
raise ValueError('Expected Float|Rational|Integer, not %s' % n)
elif isinstance(factors, Basic) and not factors.args:
factors = {factors: S.One}
elif isinstance(factors, Expr):
c, nc = factors.args_cnc()
i = c.count(I)
for _ in range(i):
c.remove(I)
factors = dict(Mul._from_args(c).as_powers_dict())
# Handle all rational Coefficients
for f in list(factors.keys()):
if isinstance(f, Rational) and not isinstance(f, Integer):
p, q = Integer(f.p), Integer(f.q)
factors[p] = (factors[p] if p in factors else S.Zero) + factors[f]
factors[q] = (factors[q] if q in factors else S.Zero) - factors[f]
factors.pop(f)
if i:
factors[I] = factors.get(I, S.Zero) + i
if nc:
factors[Mul(*nc, evaluate=False)] = S.One
else:
factors = factors.copy() # /!\ should be dict-like
# tidy up -/+1 and I exponents if Rational
handle = [k for k in factors if k is I or k in (-1, 1)]
if handle:
i1 = S.One
for k in handle:
if not _isnumber(factors[k]):
continue
i1 *= k**factors.pop(k)
if i1 is not S.One:
for a in i1.args if i1.is_Mul else [i1]: # at worst, -1.0*I*(-1)**e
if a is S.NegativeOne:
factors[a] = S.One
elif a is I:
factors[I] = S.One
elif a.is_Pow:
factors[a.base] = factors.get(a.base, S.Zero) + a.exp
elif equal_valued(a, 1):
factors[a] = S.One
elif equal_valued(a, -1):
factors[-a] = S.One
factors[S.NegativeOne] = S.One
else:
raise ValueError('unexpected factor in i1: %s' % a)
self.factors = factors
keys = getattr(factors, 'keys', None)
if keys is None:
raise TypeError('expecting Expr or dictionary')
self.gens = frozenset(keys())
def __hash__(self): # Factors
keys = tuple(ordered(self.factors.keys()))
values = [self.factors[k] for k in keys]
return hash((keys, values))
def __repr__(self): # Factors
return "Factors({%s})" % ', '.join(
['%s: %s' % (k, v) for k, v in ordered(self.factors.items())])
@property
def is_zero(self): # Factors
"""
>>> from sympy.core.exprtools import Factors
>>> Factors(0).is_zero
True
"""
f = self.factors
return len(f) == 1 and S.Zero in f
@property
def is_one(self): # Factors
"""
>>> from sympy.core.exprtools import Factors
>>> Factors(1).is_one
True
"""
return not self.factors
def as_expr(self): # Factors
"""Return the underlying expression.
Examples
========
>>> from sympy.core.exprtools import Factors
>>> from sympy.abc import x, y
>>> Factors((x*y**2).as_powers_dict()).as_expr()
x*y**2
"""
args = []
for factor, exp in self.factors.items():
if exp != 1:
if isinstance(exp, Integer):
b, e = factor.as_base_exp()
e = _keep_coeff(exp, e)
args.append(b**e)
else:
args.append(factor**exp)
else:
args.append(factor)
return Mul(*args)
def mul(self, other): # Factors
"""Return Factors of ``self * other``.
Examples
========
>>> from sympy.core.exprtools import Factors
>>> from sympy.abc import x, y, z
>>> a = Factors((x*y**2).as_powers_dict())
>>> b = Factors((x*y/z).as_powers_dict())
>>> a.mul(b)
Factors({x: 2, y: 3, z: -1})
>>> a*b
Factors({x: 2, y: 3, z: -1})
"""
if not isinstance(other, Factors):
other = Factors(other)
if any(f.is_zero for f in (self, other)):
return Factors(S.Zero)
factors = dict(self.factors)
for factor, exp in other.factors.items():
if factor in factors:
exp = factors[factor] + exp
if not exp:
del factors[factor]
continue
factors[factor] = exp
return Factors(factors)
def normal(self, other):
"""Return ``self`` and ``other`` with ``gcd`` removed from each.
The only differences between this and method ``div`` is that this
is 1) optimized for the case when there are few factors in common and
2) this does not raise an error if ``other`` is zero.
See Also
========
div
"""
if not isinstance(other, Factors):
other = Factors(other)
if other.is_zero:
return (Factors(), Factors(S.Zero))
if self.is_zero:
return (Factors(S.Zero), Factors())
self_factors = dict(self.factors)
other_factors = dict(other.factors)
for factor, self_exp in self.factors.items():
try:
other_exp = other.factors[factor]
except KeyError:
continue
exp = self_exp - other_exp
if not exp:
del self_factors[factor]
del other_factors[factor]
elif _isnumber(exp):
if exp > 0:
self_factors[factor] = exp
del other_factors[factor]
else:
del self_factors[factor]
other_factors[factor] = -exp
else:
r = self_exp.extract_additively(other_exp)
if r is not None:
if r:
self_factors[factor] = r
del other_factors[factor]
else: # should be handled already
del self_factors[factor]
del other_factors[factor]
else:
sc, sa = self_exp.as_coeff_Add()
if sc:
oc, oa = other_exp.as_coeff_Add()
diff = sc - oc
if diff > 0:
self_factors[factor] -= oc
other_exp = oa
elif diff < 0:
self_factors[factor] -= sc
other_factors[factor] -= sc
other_exp = oa - diff
else:
self_factors[factor] = sa
other_exp = oa
if other_exp:
other_factors[factor] = other_exp
else:
del other_factors[factor]
return Factors(self_factors), Factors(other_factors)
def div(self, other): # Factors
"""Return ``self`` and ``other`` with ``gcd`` removed from each.
This is optimized for the case when there are many factors in common.
Examples
========
>>> from sympy.core.exprtools import Factors
>>> from sympy.abc import x, y, z
>>> from sympy import S
>>> a = Factors((x*y**2).as_powers_dict())
>>> a.div(a)
(Factors({}), Factors({}))
>>> a.div(x*z)
(Factors({y: 2}), Factors({z: 1}))
The ``/`` operator only gives ``quo``:
>>> a/x
Factors({y: 2})
Factors treats its factors as though they are all in the numerator, so
if you violate this assumption the results will be correct but will
not strictly correspond to the numerator and denominator of the ratio:
>>> a.div(x/z)
(Factors({y: 2}), Factors({z: -1}))
Factors is also naive about bases: it does not attempt any denesting
of Rational-base terms, for example the following does not become
2**(2*x)/2.
>>> Factors(2**(2*x + 2)).div(S(8))
(Factors({2: 2*x + 2}), Factors({8: 1}))
factor_terms can clean up such Rational-bases powers:
>>> from sympy import factor_terms
>>> n, d = Factors(2**(2*x + 2)).div(S(8))
>>> n.as_expr()/d.as_expr()
2**(2*x + 2)/8
>>> factor_terms(_)
2**(2*x)/2
"""
quo, rem = dict(self.factors), {}
if not isinstance(other, Factors):
other = Factors(other)
if other.is_zero:
raise ZeroDivisionError
if self.is_zero:
return (Factors(S.Zero), Factors())
for factor, exp in other.factors.items():
if factor in quo:
d = quo[factor] - exp
if _isnumber(d):
if d <= 0:
del quo[factor]
if d >= 0:
if d:
quo[factor] = d
continue
exp = -d
else:
r = quo[factor].extract_additively(exp)
if r is not None:
if r:
quo[factor] = r
else: # should be handled already
del quo[factor]
else:
other_exp = exp
sc, sa = quo[factor].as_coeff_Add()
if sc:
oc, oa = other_exp.as_coeff_Add()
diff = sc - oc
if diff > 0:
quo[factor] -= oc
other_exp = oa
elif diff < 0:
quo[factor] -= sc
other_exp = oa - diff
else:
quo[factor] = sa
other_exp = oa
if other_exp:
rem[factor] = other_exp
else:
assert factor not in rem
continue
rem[factor] = exp
return Factors(quo), Factors(rem)
def quo(self, other): # Factors
"""Return numerator Factor of ``self / other``.
Examples
========
>>> from sympy.core.exprtools import Factors
>>> from sympy.abc import x, y, z
>>> a = Factors((x*y**2).as_powers_dict())
>>> b = Factors((x*y/z).as_powers_dict())
>>> a.quo(b) # same as a/b
Factors({y: 1})
"""
return self.div(other)[0]
def rem(self, other): # Factors
"""Return denominator Factors of ``self / other``.
Examples
========
>>> from sympy.core.exprtools import Factors
>>> from sympy.abc import x, y, z
>>> a = Factors((x*y**2).as_powers_dict())
>>> b = Factors((x*y/z).as_powers_dict())
>>> a.rem(b)
Factors({z: -1})
>>> a.rem(a)
Factors({})
"""
return self.div(other)[1]
def pow(self, other): # Factors
"""Return self raised to a non-negative integer power.
Examples
========
>>> from sympy.core.exprtools import Factors
>>> from sympy.abc import x, y
>>> a = Factors((x*y**2).as_powers_dict())
>>> a**2
Factors({x: 2, y: 4})
"""
if isinstance(other, Factors):
other = other.as_expr()
if other.is_Integer:
other = int(other)
if isinstance(other, SYMPY_INTS) and other >= 0:
factors = {}
if other:
for factor, exp in self.factors.items():
factors[factor] = exp*other
return Factors(factors)
else:
raise ValueError("expected non-negative integer, got %s" % other)
def gcd(self, other): # Factors
"""Return Factors of ``gcd(self, other)``. The keys are
the intersection of factors with the minimum exponent for
each factor.
Examples
========
>>> from sympy.core.exprtools import Factors
>>> from sympy.abc import x, y, z
>>> a = Factors((x*y**2).as_powers_dict())
>>> b = Factors((x*y/z).as_powers_dict())
>>> a.gcd(b)
Factors({x: 1, y: 1})
"""
if not isinstance(other, Factors):
other = Factors(other)
if other.is_zero:
return Factors(self.factors)
factors = {}
for factor, exp in self.factors.items():
factor, exp = sympify(factor), sympify(exp)
if factor in other.factors:
lt = (exp - other.factors[factor]).is_negative
if lt == True:
factors[factor] = exp
elif lt == False:
factors[factor] = other.factors[factor]
return Factors(factors)
def lcm(self, other): # Factors
"""Return Factors of ``lcm(self, other)`` which are
the union of factors with the maximum exponent for
each factor.
Examples
========
>>> from sympy.core.exprtools import Factors
>>> from sympy.abc import x, y, z
>>> a = Factors((x*y**2).as_powers_dict())
>>> b = Factors((x*y/z).as_powers_dict())
>>> a.lcm(b)
Factors({x: 1, y: 2, z: -1})
"""
if not isinstance(other, Factors):
other = Factors(other)
if any(f.is_zero for f in (self, other)):
return Factors(S.Zero)
factors = dict(self.factors)
for factor, exp in other.factors.items():
if factor in factors:
exp = max(exp, factors[factor])
factors[factor] = exp
return Factors(factors)
def __mul__(self, other): # Factors
return self.mul(other)
def __divmod__(self, other): # Factors
return self.div(other)
def __truediv__(self, other): # Factors
return self.quo(other)
def __mod__(self, other): # Factors
return self.rem(other)
def __pow__(self, other): # Factors
return self.pow(other)
def __eq__(self, other): # Factors
if not isinstance(other, Factors):
other = Factors(other)
return self.factors == other.factors
def __ne__(self, other): # Factors
return not self == other
class Term:
"""Efficient representation of ``coeff*(numer/denom)``. """
__slots__ = ('coeff', 'numer', 'denom')
def __init__(self, term, numer=None, denom=None): # Term
if numer is None and denom is None:
if not term.is_commutative:
raise NonCommutativeExpression(
'commutative expression expected')
coeff, factors = term.as_coeff_mul()
numer, denom = defaultdict(int), defaultdict(int)
for factor in factors:
base, exp = decompose_power(factor)
if base.is_Add:
cont, base = base.primitive()
coeff *= cont**exp
if exp > 0:
numer[base] += exp
else:
denom[base] += -exp
numer = Factors(numer)
denom = Factors(denom)
else:
coeff = term
if numer is None:
numer = Factors()
if denom is None:
denom = Factors()
self.coeff = coeff
self.numer = numer
self.denom = denom
def __hash__(self): # Term
return hash((self.coeff, self.numer, self.denom))
def __repr__(self): # Term
return "Term(%s, %s, %s)" % (self.coeff, self.numer, self.denom)
def as_expr(self): # Term
return self.coeff*(self.numer.as_expr()/self.denom.as_expr())
def mul(self, other): # Term
coeff = self.coeff*other.coeff
numer = self.numer.mul(other.numer)
denom = self.denom.mul(other.denom)
numer, denom = numer.normal(denom)
return Term(coeff, numer, denom)
def inv(self): # Term
return Term(1/self.coeff, self.denom, self.numer)
def quo(self, other): # Term
return self.mul(other.inv())
def pow(self, other): # Term
if other < 0:
return self.inv().pow(-other)
else:
return Term(self.coeff ** other,
self.numer.pow(other),
self.denom.pow(other))
def gcd(self, other): # Term
return Term(self.coeff.gcd(other.coeff),
self.numer.gcd(other.numer),
self.denom.gcd(other.denom))
def lcm(self, other): # Term
return Term(self.coeff.lcm(other.coeff),
self.numer.lcm(other.numer),
self.denom.lcm(other.denom))
def __mul__(self, other): # Term
if isinstance(other, Term):
return self.mul(other)
else:
return NotImplemented
def __truediv__(self, other): # Term
if isinstance(other, Term):
return self.quo(other)
else:
return NotImplemented
def __pow__(self, other): # Term
if isinstance(other, SYMPY_INTS):
return self.pow(other)
else:
return NotImplemented
def __eq__(self, other): # Term
return (self.coeff == other.coeff and
self.numer == other.numer and
self.denom == other.denom)
def __ne__(self, other): # Term
return not self == other
def _gcd_terms(terms, isprimitive=False, fraction=True):
"""Helper function for :func:`gcd_terms`.
Parameters
==========
isprimitive : boolean, optional
If ``isprimitive`` is True then the call to primitive
for an Add will be skipped. This is useful when the
content has already been extracted.
fraction : boolean, optional
If ``fraction`` is True then the expression will appear over a common
denominator, the lcm of all term denominators.
"""
if isinstance(terms, Basic) and not isinstance(terms, Tuple):
terms = Add.make_args(terms)
terms = list(map(Term, [t for t in terms if t]))
# there is some simplification that may happen if we leave this
# here rather than duplicate it before the mapping of Term onto
# the terms
if len(terms) == 0:
return S.Zero, S.Zero, S.One
if len(terms) == 1:
cont = terms[0].coeff
numer = terms[0].numer.as_expr()
denom = terms[0].denom.as_expr()
else:
cont = terms[0]
for term in terms[1:]:
cont = cont.gcd(term)
for i, term in enumerate(terms):
terms[i] = term.quo(cont)
if fraction:
denom = terms[0].denom
for term in terms[1:]:
denom = denom.lcm(term.denom)
numers = []
for term in terms:
numer = term.numer.mul(denom.quo(term.denom))
numers.append(term.coeff*numer.as_expr())
else:
numers = [t.as_expr() for t in terms]
denom = Term(S.One).numer
cont = cont.as_expr()
numer = Add(*numers)
denom = denom.as_expr()
if not isprimitive and numer.is_Add:
_cont, numer = numer.primitive()
cont *= _cont
return cont, numer, denom
def gcd_terms(terms, isprimitive=False, clear=True, fraction=True):
"""Compute the GCD of ``terms`` and put them together.
Parameters
==========
terms : Expr
Can be an expression or a non-Basic sequence of expressions
which will be handled as though they are terms from a sum.
isprimitive : bool, optional
If ``isprimitive`` is True the _gcd_terms will not run the primitive
method on the terms.
clear : bool, optional
It controls the removal of integers from the denominator of an Add
expression. When True (default), all numerical denominator will be cleared;
when False the denominators will be cleared only if all terms had numerical
denominators other than 1.
fraction : bool, optional
When True (default), will put the expression over a common
denominator.
Examples
========
>>> from sympy import gcd_terms
>>> from sympy.abc import x, y
>>> gcd_terms((x + 1)**2*y + (x + 1)*y**2)
y*(x + 1)*(x + y + 1)
>>> gcd_terms(x/2 + 1)
(x + 2)/2
>>> gcd_terms(x/2 + 1, clear=False)
x/2 + 1
>>> gcd_terms(x/2 + y/2, clear=False)
(x + y)/2
>>> gcd_terms(x/2 + 1/x)
(x**2 + 2)/(2*x)
>>> gcd_terms(x/2 + 1/x, fraction=False)
(x + 2/x)/2
>>> gcd_terms(x/2 + 1/x, fraction=False, clear=False)
x/2 + 1/x
>>> gcd_terms(x/2/y + 1/x/y)
(x**2 + 2)/(2*x*y)
>>> gcd_terms(x/2/y + 1/x/y, clear=False)
(x**2/2 + 1)/(x*y)
>>> gcd_terms(x/2/y + 1/x/y, clear=False, fraction=False)
(x/2 + 1/x)/y
The ``clear`` flag was ignored in this case because the returned
expression was a rational expression, not a simple sum.
See Also
========
factor_terms, sympy.polys.polytools.terms_gcd
"""
def mask(terms):
"""replace nc portions of each term with a unique Dummy symbols
and return the replacements to restore them"""
args = [(a, []) if a.is_commutative else a.args_cnc() for a in terms]
reps = []
for i, (c, nc) in enumerate(args):
if nc:
nc = Mul(*nc)
d = Dummy()
reps.append((d, nc))
c.append(d)
args[i] = Mul(*c)
else:
args[i] = c
return args, dict(reps)
isadd = isinstance(terms, Add)
addlike = isadd or not isinstance(terms, Basic) and \
is_sequence(terms, include=set) and \
not isinstance(terms, Dict)
if addlike:
if isadd: # i.e. an Add
terms = list(terms.args)
else:
terms = sympify(terms)
terms, reps = mask(terms)
cont, numer, denom = _gcd_terms(terms, isprimitive, fraction)
numer = numer.xreplace(reps)
coeff, factors = cont.as_coeff_Mul()
if not clear:
c, _coeff = coeff.as_coeff_Mul()
if not c.is_Integer and not clear and numer.is_Add:
n, d = c.as_numer_denom()
_numer = numer/d
if any(a.as_coeff_Mul()[0].is_Integer
for a in _numer.args):
numer = _numer
coeff = n*_coeff
return _keep_coeff(coeff, factors*numer/denom, clear=clear)
if not isinstance(terms, Basic):
return terms
if terms.is_Atom:
return terms
if terms.is_Mul:
c, args = terms.as_coeff_mul()
return _keep_coeff(c, Mul(*[gcd_terms(i, isprimitive, clear, fraction)
for i in args]), clear=clear)
def handle(a):
# don't treat internal args like terms of an Add
if not isinstance(a, Expr):
if isinstance(a, Basic):
if not a.args:
return a
return a.func(*[handle(i) for i in a.args])
return type(a)([handle(i) for i in a])
return gcd_terms(a, isprimitive, clear, fraction)
if isinstance(terms, Dict):
return Dict(*[(k, handle(v)) for k, v in terms.args])
return terms.func(*[handle(i) for i in terms.args])
def _factor_sum_int(expr, **kwargs):
"""Return Sum or Integral object with factors that are not
in the wrt variables removed. In cases where there are additive
terms in the function of the object that are independent, the
object will be separated into two objects.
Examples
========
>>> from sympy import Sum, factor_terms
>>> from sympy.abc import x, y
>>> factor_terms(Sum(x + y, (x, 1, 3)))
y*Sum(1, (x, 1, 3)) + Sum(x, (x, 1, 3))
>>> factor_terms(Sum(x*y, (x, 1, 3)))
y*Sum(x, (x, 1, 3))
Notes
=====
If a function in the summand or integrand is replaced
with a symbol, then this simplification should not be
done or else an incorrect result will be obtained when
the symbol is replaced with an expression that depends
on the variables of summation/integration:
>>> eq = Sum(y, (x, 1, 3))
>>> factor_terms(eq).subs(y, x).doit()
3*x
>>> eq.subs(y, x).doit()
6
"""
result = expr.function
if result == 0:
return S.Zero
limits = expr.limits
# get the wrt variables
wrt = {i.args[0] for i in limits}
# factor out any common terms that are independent of wrt
f = factor_terms(result, **kwargs)
i, d = f.as_independent(*wrt)
if isinstance(f, Add):
return i * expr.func(1, *limits) + expr.func(d, *limits)
else:
return i * expr.func(d, *limits)
def factor_terms(expr, radical=False, clear=False, fraction=False, sign=True):
"""Remove common factors from terms in all arguments without
changing the underlying structure of the expr. No expansion or
simplification (and no processing of non-commutatives) is performed.
Parameters
==========
radical: bool, optional
If radical=True then a radical common to all terms will be factored
out of any Add sub-expressions of the expr.
clear : bool, optional
If clear=False (default) then coefficients will not be separated
from a single Add if they can be distributed to leave one or more
terms with integer coefficients.
fraction : bool, optional
If fraction=True (default is False) then a common denominator will be
constructed for the expression.
sign : bool, optional
If sign=True (default) then even if the only factor in common is a -1,
it will be factored out of the expression.
Examples
========
>>> from sympy import factor_terms, Symbol
>>> from sympy.abc import x, y
>>> factor_terms(x + x*(2 + 4*y)**3)
x*(8*(2*y + 1)**3 + 1)
>>> A = Symbol('A', commutative=False)
>>> factor_terms(x*A + x*A + x*y*A)
x*(y*A + 2*A)
When ``clear`` is False, a rational will only be factored out of an
Add expression if all terms of the Add have coefficients that are
fractions:
>>> factor_terms(x/2 + 1, clear=False)
x/2 + 1
>>> factor_terms(x/2 + 1, clear=True)
(x + 2)/2
If a -1 is all that can be factored out, to *not* factor it out, the
flag ``sign`` must be False:
>>> factor_terms(-x - y)
-(x + y)
>>> factor_terms(-x - y, sign=False)
-x - y
>>> factor_terms(-2*x - 2*y, sign=False)
-2*(x + y)
See Also
========
gcd_terms, sympy.polys.polytools.terms_gcd
"""
def do(expr):
from sympy.concrete.summations import Sum
from sympy.integrals.integrals import Integral
is_iterable = iterable(expr)
if not isinstance(expr, Basic) or expr.is_Atom:
if is_iterable:
return type(expr)([do(i) for i in expr])
return expr
if expr.is_Pow or expr.is_Function or \
is_iterable or not hasattr(expr, 'args_cnc'):
args = expr.args
newargs = tuple([do(i) for i in args])
if newargs == args:
return expr
return expr.func(*newargs)
if isinstance(expr, (Sum, Integral)):
return _factor_sum_int(expr,
radical=radical, clear=clear,
fraction=fraction, sign=sign)
cont, p = expr.as_content_primitive(radical=radical, clear=clear)
if p.is_Add:
list_args = [do(a) for a in Add.make_args(p)]
# get a common negative (if there) which gcd_terms does not remove
if not any(a.as_coeff_Mul()[0].extract_multiplicatively(-1) is None
for a in list_args):
cont = -cont
list_args = [-a for a in list_args]
# watch out for exp(-(x+2)) which gcd_terms will change to exp(-x-2)
special = {}
for i, a in enumerate(list_args):
b, e = a.as_base_exp()
if e.is_Mul and e != Mul(*e.args):
list_args[i] = Dummy()
special[list_args[i]] = a
# rebuild p not worrying about the order which gcd_terms will fix
p = Add._from_args(list_args)
p = gcd_terms(p,
isprimitive=True,
clear=clear,
fraction=fraction).xreplace(special)
elif p.args:
p = p.func(
*[do(a) for a in p.args])
rv = _keep_coeff(cont, p, clear=clear, sign=sign)
return rv
expr = sympify(expr)
return do(expr)
def _mask_nc(eq, name=None):
"""
Return ``eq`` with non-commutative objects replaced with Dummy
symbols. A dictionary that can be used to restore the original
values is returned: if it is None, the expression is noncommutative
and cannot be made commutative. The third value returned is a list
of any non-commutative symbols that appear in the returned equation.
Explanation
===========
All non-commutative objects other than Symbols are replaced with
a non-commutative Symbol. Identical objects will be identified
by identical symbols.
If there is only 1 non-commutative object in an expression it will
be replaced with a commutative symbol. Otherwise, the non-commutative
entities are retained and the calling routine should handle
replacements in this case since some care must be taken to keep
track of the ordering of symbols when they occur within Muls.
Parameters
==========
name : str
``name``, if given, is the name that will be used with numbered Dummy
variables that will replace the non-commutative objects and is mainly
used for doctesting purposes.
Examples
========
>>> from sympy.physics.secondquant import Commutator, NO, F, Fd
>>> from sympy import symbols
>>> from sympy.core.exprtools import _mask_nc
>>> from sympy.abc import x, y
>>> A, B, C = symbols('A,B,C', commutative=False)
One nc-symbol:
>>> _mask_nc(A**2 - x**2, 'd')
(_d0**2 - x**2, {_d0: A}, [])
Multiple nc-symbols:
>>> _mask_nc(A**2 - B**2, 'd')
(A**2 - B**2, {}, [A, B])
An nc-object with nc-symbols but no others outside of it:
>>> _mask_nc(1 + x*Commutator(A, B), 'd')
(_d0*x + 1, {_d0: Commutator(A, B)}, [])
>>> _mask_nc(NO(Fd(x)*F(y)), 'd')
(_d0, {_d0: NO(CreateFermion(x)*AnnihilateFermion(y))}, [])
Multiple nc-objects:
>>> eq = x*Commutator(A, B) + x*Commutator(A, C)*Commutator(A, B)
>>> _mask_nc(eq, 'd')
(x*_d0 + x*_d1*_d0, {_d0: Commutator(A, B), _d1: Commutator(A, C)}, [_d0, _d1])
Multiple nc-objects and nc-symbols:
>>> eq = A*Commutator(A, B) + B*Commutator(A, C)
>>> _mask_nc(eq, 'd')
(A*_d0 + B*_d1, {_d0: Commutator(A, B), _d1: Commutator(A, C)}, [_d0, _d1, A, B])
"""
name = name or 'mask'
# Make Dummy() append sequential numbers to the name
def numbered_names():
i = 0
while True:
yield name + str(i)
i += 1
names = numbered_names()
def Dummy(*args, **kwargs):
from .symbol import Dummy
return Dummy(next(names), *args, **kwargs)
expr = eq
if expr.is_commutative:
return eq, {}, []
# identify nc-objects; symbols and other
rep = []
nc_obj = set()
nc_syms = set()
pot = preorder_traversal(expr, keys=default_sort_key)
for i, a in enumerate(pot):
if any(a == r[0] for r in rep):
pot.skip()
elif not a.is_commutative:
if a.is_symbol:
nc_syms.add(a)
pot.skip()
elif not (a.is_Add or a.is_Mul or a.is_Pow):
nc_obj.add(a)
pot.skip()
# If there is only one nc symbol or object, it can be factored regularly
# but polys is going to complain, so replace it with a Dummy.
if len(nc_obj) == 1 and not nc_syms:
rep.append((nc_obj.pop(), Dummy()))
elif len(nc_syms) == 1 and not nc_obj:
rep.append((nc_syms.pop(), Dummy()))
# Any remaining nc-objects will be replaced with an nc-Dummy and
# identified as an nc-Symbol to watch out for
nc_obj = sorted(nc_obj, key=default_sort_key)
for n in nc_obj:
nc = Dummy(commutative=False)
rep.append((n, nc))
nc_syms.add(nc)
expr = expr.subs(rep)
nc_syms = list(nc_syms)
nc_syms.sort(key=default_sort_key)
return expr, {v: k for k, v in rep}, nc_syms
def factor_nc(expr):
"""Return the factored form of ``expr`` while handling non-commutative
expressions.
Examples
========
>>> from sympy import factor_nc, Symbol
>>> from sympy.abc import x
>>> A = Symbol('A', commutative=False)
>>> B = Symbol('B', commutative=False)
>>> factor_nc((x**2 + 2*A*x + A**2).expand())
(x + A)**2
>>> factor_nc(((x + A)*(x + B)).expand())
(x + A)*(x + B)
"""
expr = sympify(expr)
if not isinstance(expr, Expr) or not expr.args:
return expr
if not expr.is_Add:
return expr.func(*[factor_nc(a) for a in expr.args])
expr = expr.func(*[expand_power_exp(i) for i in expr.args])
from sympy.polys.polytools import gcd, factor
expr, rep, nc_symbols = _mask_nc(expr)
if rep:
return factor(expr).subs(rep)
else:
args = [a.args_cnc() for a in Add.make_args(expr)]
c = g = l = r = S.One
hit = False
# find any commutative gcd term
for i, a in enumerate(args):
if i == 0:
c = Mul._from_args(a[0])
elif a[0]:
c = gcd(c, Mul._from_args(a[0]))
else:
c = S.One
if c is not S.One:
hit = True
c, g = c.as_coeff_Mul()
if g is not S.One:
for i, (cc, _) in enumerate(args):
cc = list(Mul.make_args(Mul._from_args(list(cc))/g))
args[i][0] = cc
for i, (cc, _) in enumerate(args):
if cc:
cc[0] = cc[0]/c
else:
cc = [1/c]
args[i][0] = cc
# find any noncommutative common prefix
for i, a in enumerate(args):
if i == 0:
n = a[1][:]
else:
n = common_prefix(n, a[1])
if not n:
# is there a power that can be extracted?
if not args[0][1]:
break
b, e = args[0][1][0].as_base_exp()
ok = False
if e.is_Integer:
for t in args:
if not t[1]:
break
bt, et = t[1][0].as_base_exp()
if et.is_Integer and bt == b:
e = min(e, et)
else:
break
else:
ok = hit = True
l = b**e
il = b**-e
for _ in args:
_[1][0] = il*_[1][0]
break
if not ok:
break
else:
hit = True
lenn = len(n)
l = Mul(*n)
for _ in args:
_[1] = _[1][lenn:]
# find any noncommutative common suffix
for i, a in enumerate(args):
if i == 0:
n = a[1][:]
else:
n = common_suffix(n, a[1])
if not n:
# is there a power that can be extracted?
if not args[0][1]:
break
b, e = args[0][1][-1].as_base_exp()
ok = False
if e.is_Integer:
for t in args:
if not t[1]:
break
bt, et = t[1][-1].as_base_exp()
if et.is_Integer and bt == b:
e = min(e, et)
else:
break
else:
ok = hit = True
r = b**e
il = b**-e
for _ in args:
_[1][-1] = _[1][-1]*il
break
if not ok:
break
else:
hit = True
lenn = len(n)
r = Mul(*n)
for _ in args:
_[1] = _[1][:len(_[1]) - lenn]
if hit:
mid = Add(*[Mul(*cc)*Mul(*nc) for cc, nc in args])
else:
mid = expr
from sympy.simplify.powsimp import powsimp
# sort the symbols so the Dummys would appear in the same
# order as the original symbols, otherwise you may introduce
# a factor of -1, e.g. A**2 - B**2) -- {A:y, B:x} --> y**2 - x**2
# and the former factors into two terms, (A - B)*(A + B) while the
# latter factors into 3 terms, (-1)*(x - y)*(x + y)
rep1 = [(n, Dummy()) for n in sorted(nc_symbols, key=default_sort_key)]
unrep1 = [(v, k) for k, v in rep1]
unrep1.reverse()
new_mid, r2, _ = _mask_nc(mid.subs(rep1))
new_mid = powsimp(factor(new_mid))
new_mid = new_mid.subs(r2).subs(unrep1)
if new_mid.is_Pow:
return _keep_coeff(c, g*l*new_mid*r)
if new_mid.is_Mul:
def _pemexpand(expr):
"Expand with the minimal set of hints necessary to check the result."
return expr.expand(deep=True, mul=True, power_exp=True,
power_base=False, basic=False, multinomial=True, log=False)
# XXX TODO there should be a way to inspect what order the terms
# must be in and just select the plausible ordering without
# checking permutations
cfac = []
ncfac = []
for f in new_mid.args:
if f.is_commutative:
cfac.append(f)
else:
b, e = f.as_base_exp()
if e.is_Integer:
ncfac.extend([b]*e)
else:
ncfac.append(f)
pre_mid = g*Mul(*cfac)*l
target = _pemexpand(expr/c)
for s in variations(ncfac, len(ncfac)):
ok = pre_mid*Mul(*s)*r
if _pemexpand(ok) == target:
return _keep_coeff(c, ok)
# mid was an Add that didn't factor successfully
return _keep_coeff(c, g*l*mid*r)
PK ]ZZZ9:�
ZL ZL sympy/core/facts.pyr"""This is rule-based deduction system for SymPy
The whole thing is split into two parts
- rules compilation and preparation of tables
- runtime inference
For rule-based inference engines, the classical work is RETE algorithm [1],
[2] Although we are not implementing it in full (or even significantly)
it's still worth a read to understand the underlying ideas.
In short, every rule in a system of rules is one of two forms:
- atom -> ... (alpha rule)
- And(atom1, atom2, ...) -> ... (beta rule)
The major complexity is in efficient beta-rules processing and usually for an
expert system a lot of effort goes into code that operates on beta-rules.
Here we take minimalistic approach to get something usable first.
- (preparation) of alpha- and beta- networks, everything except
- (runtime) FactRules.deduce_all_facts
_____________________________________
( Kirr: I've never thought that doing )
( logic stuff is that difficult... )
-------------------------------------
o ^__^
o (oo)\_______
(__)\ )\/\
||----w |
|| ||
Some references on the topic
----------------------------
[1] https://en.wikipedia.org/wiki/Rete_algorithm
[2] http://reports-archive.adm.cs.cmu.edu/anon/1995/CMU-CS-95-113.pdf
https://en.wikipedia.org/wiki/Propositional_formula
https://en.wikipedia.org/wiki/Inference_rule
https://en.wikipedia.org/wiki/List_of_rules_of_inference
"""
from collections import defaultdict
from typing import Iterator
from .logic import Logic, And, Or, Not
def _base_fact(atom):
"""Return the literal fact of an atom.
Effectively, this merely strips the Not around a fact.
"""
if isinstance(atom, Not):
return atom.arg
else:
return atom
def _as_pair(atom):
if isinstance(atom, Not):
return (atom.arg, False)
else:
return (atom, True)
# XXX this prepares forward-chaining rules for alpha-network
def transitive_closure(implications):
"""
Computes the transitive closure of a list of implications
Uses Warshall's algorithm, as described at
http://www.cs.hope.edu/~cusack/Notes/Notes/DiscreteMath/Warshall.pdf.
"""
full_implications = set(implications)
literals = set().union(*map(set, full_implications))
for k in literals:
for i in literals:
if (i, k) in full_implications:
for j in literals:
if (k, j) in full_implications:
full_implications.add((i, j))
return full_implications
def deduce_alpha_implications(implications):
"""deduce all implications
Description by example
----------------------
given set of logic rules:
a -> b
b -> c
we deduce all possible rules:
a -> b, c
b -> c
implications: [] of (a,b)
return: {} of a -> set([b, c, ...])
"""
implications = implications + [(Not(j), Not(i)) for (i, j) in implications]
res = defaultdict(set)
full_implications = transitive_closure(implications)
for a, b in full_implications:
if a == b:
continue # skip a->a cyclic input
res[a].add(b)
# Clean up tautologies and check consistency
for a, impl in res.items():
impl.discard(a)
na = Not(a)
if na in impl:
raise ValueError(
'implications are inconsistent: %s -> %s %s' % (a, na, impl))
return res
def apply_beta_to_alpha_route(alpha_implications, beta_rules):
"""apply additional beta-rules (And conditions) to already-built
alpha implication tables
TODO: write about
- static extension of alpha-chains
- attaching refs to beta-nodes to alpha chains
e.g.
alpha_implications:
a -> [b, !c, d]
b -> [d]
...
beta_rules:
&(b,d) -> e
then we'll extend a's rule to the following
a -> [b, !c, d, e]
"""
x_impl = {}
for x in alpha_implications.keys():
x_impl[x] = (set(alpha_implications[x]), [])
for bcond, bimpl in beta_rules:
for bk in bcond.args:
if bk in x_impl:
continue
x_impl[bk] = (set(), [])
# static extensions to alpha rules:
# A: x -> a,b B: &(a,b) -> c ==> A: x -> a,b,c
seen_static_extension = True
while seen_static_extension:
seen_static_extension = False
for bcond, bimpl in beta_rules:
if not isinstance(bcond, And):
raise TypeError("Cond is not And")
bargs = set(bcond.args)
for x, (ximpls, bb) in x_impl.items():
x_all = ximpls | {x}
# A: ... -> a B: &(...) -> a is non-informative
if bimpl not in x_all and bargs.issubset(x_all):
ximpls.add(bimpl)
# we introduced new implication - now we have to restore
# completeness of the whole set.
bimpl_impl = x_impl.get(bimpl)
if bimpl_impl is not None:
ximpls |= bimpl_impl[0]
seen_static_extension = True
# attach beta-nodes which can be possibly triggered by an alpha-chain
for bidx, (bcond, bimpl) in enumerate(beta_rules):
bargs = set(bcond.args)
for x, (ximpls, bb) in x_impl.items():
x_all = ximpls | {x}
# A: ... -> a B: &(...) -> a (non-informative)
if bimpl in x_all:
continue
# A: x -> a... B: &(!a,...) -> ... (will never trigger)
# A: x -> a... B: &(...) -> !a (will never trigger)
if any(Not(xi) in bargs or Not(xi) == bimpl for xi in x_all):
continue
if bargs & x_all:
bb.append(bidx)
return x_impl
def rules_2prereq(rules):
"""build prerequisites table from rules
Description by example
----------------------
given set of logic rules:
a -> b, c
b -> c
we build prerequisites (from what points something can be deduced):
b <- a
c <- a, b
rules: {} of a -> [b, c, ...]
return: {} of c <- [a, b, ...]
Note however, that this prerequisites may be *not* enough to prove a
fact. An example is 'a -> b' rule, where prereq(a) is b, and prereq(b)
is a. That's because a=T -> b=T, and b=F -> a=F, but a=F -> b=?
"""
prereq = defaultdict(set)
for (a, _), impl in rules.items():
if isinstance(a, Not):
a = a.args[0]
for (i, _) in impl:
if isinstance(i, Not):
i = i.args[0]
prereq[i].add(a)
return prereq
################
# RULES PROVER #
################
class TautologyDetected(Exception):
"""(internal) Prover uses it for reporting detected tautology"""
pass
class Prover:
"""ai - prover of logic rules
given a set of initial rules, Prover tries to prove all possible rules
which follow from given premises.
As a result proved_rules are always either in one of two forms: alpha or
beta:
Alpha rules
-----------
This are rules of the form::
a -> b & c & d & ...
Beta rules
----------
This are rules of the form::
&(a,b,...) -> c & d & ...
i.e. beta rules are join conditions that say that something follows when
*several* facts are true at the same time.
"""
def __init__(self):
self.proved_rules = []
self._rules_seen = set()
def split_alpha_beta(self):
"""split proved rules into alpha and beta chains"""
rules_alpha = [] # a -> b
rules_beta = [] # &(...) -> b
for a, b in self.proved_rules:
if isinstance(a, And):
rules_beta.append((a, b))
else:
rules_alpha.append((a, b))
return rules_alpha, rules_beta
@property
def rules_alpha(self):
return self.split_alpha_beta()[0]
@property
def rules_beta(self):
return self.split_alpha_beta()[1]
def process_rule(self, a, b):
"""process a -> b rule""" # TODO write more?
if (not a) or isinstance(b, bool):
return
if isinstance(a, bool):
return
if (a, b) in self._rules_seen:
return
else:
self._rules_seen.add((a, b))
# this is the core of processing
try:
self._process_rule(a, b)
except TautologyDetected:
pass
def _process_rule(self, a, b):
# right part first
# a -> b & c --> a -> b ; a -> c
# (?) FIXME this is only correct when b & c != null !
if isinstance(b, And):
sorted_bargs = sorted(b.args, key=str)
for barg in sorted_bargs:
self.process_rule(a, barg)
# a -> b | c --> !b & !c -> !a
# --> a & !b -> c
# --> a & !c -> b
elif isinstance(b, Or):
sorted_bargs = sorted(b.args, key=str)
# detect tautology first
if not isinstance(a, Logic): # Atom
# tautology: a -> a|c|...
if a in sorted_bargs:
raise TautologyDetected(a, b, 'a -> a|c|...')
self.process_rule(And(*[Not(barg) for barg in b.args]), Not(a))
for bidx in range(len(sorted_bargs)):
barg = sorted_bargs[bidx]
brest = sorted_bargs[:bidx] + sorted_bargs[bidx + 1:]
self.process_rule(And(a, Not(barg)), Or(*brest))
# left part
# a & b -> c --> IRREDUCIBLE CASE -- WE STORE IT AS IS
# (this will be the basis of beta-network)
elif isinstance(a, And):
sorted_aargs = sorted(a.args, key=str)
if b in sorted_aargs:
raise TautologyDetected(a, b, 'a & b -> a')
self.proved_rules.append((a, b))
# XXX NOTE at present we ignore !c -> !a | !b
elif isinstance(a, Or):
sorted_aargs = sorted(a.args, key=str)
if b in sorted_aargs:
raise TautologyDetected(a, b, 'a | b -> a')
for aarg in sorted_aargs:
self.process_rule(aarg, b)
else:
# both `a` and `b` are atoms
self.proved_rules.append((a, b)) # a -> b
self.proved_rules.append((Not(b), Not(a))) # !b -> !a
########################################
class FactRules:
"""Rules that describe how to deduce facts in logic space
When defined, these rules allow implications to quickly be determined
for a set of facts. For this precomputed deduction tables are used.
see `deduce_all_facts` (forward-chaining)
Also it is possible to gather prerequisites for a fact, which is tried
to be proven. (backward-chaining)
Definition Syntax
-----------------
a -> b -- a=T -> b=T (and automatically b=F -> a=F)
a -> !b -- a=T -> b=F
a == b -- a -> b & b -> a
a -> b & c -- a=T -> b=T & c=T
# TODO b | c
Internals
---------
.full_implications[k, v]: all the implications of fact k=v
.beta_triggers[k, v]: beta rules that might be triggered when k=v
.prereq -- {} k <- [] of k's prerequisites
.defined_facts -- set of defined fact names
"""
def __init__(self, rules):
"""Compile rules into internal lookup tables"""
if isinstance(rules, str):
rules = rules.splitlines()
# --- parse and process rules ---
P = Prover()
for rule in rules:
# XXX `a` is hardcoded to be always atom
a, op, b = rule.split(None, 2)
a = Logic.fromstring(a)
b = Logic.fromstring(b)
if op == '->':
P.process_rule(a, b)
elif op == '==':
P.process_rule(a, b)
P.process_rule(b, a)
else:
raise ValueError('unknown op %r' % op)
# --- build deduction networks ---
self.beta_rules = []
for bcond, bimpl in P.rules_beta:
self.beta_rules.append(
({_as_pair(a) for a in bcond.args}, _as_pair(bimpl)))
# deduce alpha implications
impl_a = deduce_alpha_implications(P.rules_alpha)
# now:
# - apply beta rules to alpha chains (static extension), and
# - further associate beta rules to alpha chain (for inference
# at runtime)
impl_ab = apply_beta_to_alpha_route(impl_a, P.rules_beta)
# extract defined fact names
self.defined_facts = {_base_fact(k) for k in impl_ab.keys()}
# build rels (forward chains)
full_implications = defaultdict(set)
beta_triggers = defaultdict(set)
for k, (impl, betaidxs) in impl_ab.items():
full_implications[_as_pair(k)] = {_as_pair(i) for i in impl}
beta_triggers[_as_pair(k)] = betaidxs
self.full_implications = full_implications
self.beta_triggers = beta_triggers
# build prereq (backward chains)
prereq = defaultdict(set)
rel_prereq = rules_2prereq(full_implications)
for k, pitems in rel_prereq.items():
prereq[k] |= pitems
self.prereq = prereq
def _to_python(self) -> str:
""" Generate a string with plain python representation of the instance """
return '\n'.join(self.print_rules())
@classmethod
def _from_python(cls, data : dict):
""" Generate an instance from the plain python representation """
self = cls('')
for key in ['full_implications', 'beta_triggers', 'prereq']:
d=defaultdict(set)
d.update(data[key])
setattr(self, key, d)
self.beta_rules = data['beta_rules']
self.defined_facts = set(data['defined_facts'])
return self
def _defined_facts_lines(self):
yield 'defined_facts = ['
for fact in sorted(self.defined_facts):
yield f' {fact!r},'
yield '] # defined_facts'
def _full_implications_lines(self):
yield 'full_implications = dict( ['
for fact in sorted(self.defined_facts):
for value in (True, False):
yield f' # Implications of {fact} = {value}:'
yield f' (({fact!r}, {value!r}), set( ('
implications = self.full_implications[(fact, value)]
for implied in sorted(implications):
yield f' {implied!r},'
yield ' ) ),'
yield ' ),'
yield ' ] ) # full_implications'
def _prereq_lines(self):
yield 'prereq = {'
yield ''
for fact in sorted(self.prereq):
yield f' # facts that could determine the value of {fact}'
yield f' {fact!r}: {{'
for pfact in sorted(self.prereq[fact]):
yield f' {pfact!r},'
yield ' },'
yield ''
yield '} # prereq'
def _beta_rules_lines(self):
reverse_implications = defaultdict(list)
for n, (pre, implied) in enumerate(self.beta_rules):
reverse_implications[implied].append((pre, n))
yield '# Note: the order of the beta rules is used in the beta_triggers'
yield 'beta_rules = ['
yield ''
m = 0
indices = {}
for implied in sorted(reverse_implications):
fact, value = implied
yield f' # Rules implying {fact} = {value}'
for pre, n in reverse_implications[implied]:
indices[n] = m
m += 1
setstr = ", ".join(map(str, sorted(pre)))
yield f' ({{{setstr}}},'
yield f' {implied!r}),'
yield ''
yield '] # beta_rules'
yield 'beta_triggers = {'
for query in sorted(self.beta_triggers):
fact, value = query
triggers = [indices[n] for n in self.beta_triggers[query]]
yield f' {query!r}: {triggers!r},'
yield '} # beta_triggers'
def print_rules(self) -> Iterator[str]:
""" Returns a generator with lines to represent the facts and rules """
yield from self._defined_facts_lines()
yield ''
yield ''
yield from self._full_implications_lines()
yield ''
yield ''
yield from self._prereq_lines()
yield ''
yield ''
yield from self._beta_rules_lines()
yield ''
yield ''
yield "generated_assumptions = {'defined_facts': defined_facts, 'full_implications': full_implications,"
yield " 'prereq': prereq, 'beta_rules': beta_rules, 'beta_triggers': beta_triggers}"
class InconsistentAssumptions(ValueError):
def __str__(self):
kb, fact, value = self.args
return "%s, %s=%s" % (kb, fact, value)
class FactKB(dict):
"""
A simple propositional knowledge base relying on compiled inference rules.
"""
def __str__(self):
return '{\n%s}' % ',\n'.join(
["\t%s: %s" % i for i in sorted(self.items())])
def __init__(self, rules):
self.rules = rules
def _tell(self, k, v):
"""Add fact k=v to the knowledge base.
Returns True if the KB has actually been updated, False otherwise.
"""
if k in self and self[k] is not None:
if self[k] == v:
return False
else:
raise InconsistentAssumptions(self, k, v)
else:
self[k] = v
return True
# *********************************************
# * This is the workhorse, so keep it *fast*. *
# *********************************************
def deduce_all_facts(self, facts):
"""
Update the KB with all the implications of a list of facts.
Facts can be specified as a dictionary or as a list of (key, value)
pairs.
"""
# keep frequently used attributes locally, so we'll avoid extra
# attribute access overhead
full_implications = self.rules.full_implications
beta_triggers = self.rules.beta_triggers
beta_rules = self.rules.beta_rules
if isinstance(facts, dict):
facts = facts.items()
while facts:
beta_maytrigger = set()
# --- alpha chains ---
for k, v in facts:
if not self._tell(k, v) or v is None:
continue
# lookup routing tables
for key, value in full_implications[k, v]:
self._tell(key, value)
beta_maytrigger.update(beta_triggers[k, v])
# --- beta chains ---
facts = []
for bidx in beta_maytrigger:
bcond, bimpl = beta_rules[bidx]
if all(self.get(k) is v for k, v in bcond):
facts.append(bimpl)
PK ]ZZZ�UnQ#� #� sympy/core/function.py"""
There are three types of functions implemented in SymPy:
1) defined functions (in the sense that they can be evaluated) like
exp or sin; they have a name and a body:
f = exp
2) undefined function which have a name but no body. Undefined
functions can be defined using a Function class as follows:
f = Function('f')
(the result will be a Function instance)
3) anonymous function (or lambda function) which have a body (defined
with dummy variables) but have no name:
f = Lambda(x, exp(x)*x)
f = Lambda((x, y), exp(x)*y)
The fourth type of functions are composites, like (sin + cos)(x); these work in
SymPy core, but are not yet part of SymPy.
Examples
========
>>> import sympy
>>> f = sympy.Function("f")
>>> from sympy.abc import x
>>> f(x)
f(x)
>>> print(sympy.srepr(f(x).func))
Function('f')
>>> f(x).args
(x,)
"""
from __future__ import annotations
from typing import Any
from collections.abc import Iterable
from .add import Add
from .basic import Basic, _atomic
from .cache import cacheit
from .containers import Tuple, Dict
from .decorators import _sympifyit
from .evalf import pure_complex
from .expr import Expr, AtomicExpr
from .logic import fuzzy_and, fuzzy_or, fuzzy_not, FuzzyBool
from .mul import Mul
from .numbers import Rational, Float, Integer
from .operations import LatticeOp
from .parameters import global_parameters
from .rules import Transform
from .singleton import S
from .sympify import sympify, _sympify
from .sorting import default_sort_key, ordered
from sympy.utilities.exceptions import (sympy_deprecation_warning,
SymPyDeprecationWarning, ignore_warnings)
from sympy.utilities.iterables import (has_dups, sift, iterable,
is_sequence, uniq, topological_sort)
from sympy.utilities.lambdify import MPMATH_TRANSLATIONS
from sympy.utilities.misc import as_int, filldedent, func_name
import mpmath
from mpmath.libmp.libmpf import prec_to_dps
import inspect
from collections import Counter
def _coeff_isneg(a):
"""Return True if the leading Number is negative.
Examples
========
>>> from sympy.core.function import _coeff_isneg
>>> from sympy import S, Symbol, oo, pi
>>> _coeff_isneg(-3*pi)
True
>>> _coeff_isneg(S(3))
False
>>> _coeff_isneg(-oo)
True
>>> _coeff_isneg(Symbol('n', negative=True)) # coeff is 1
False
For matrix expressions:
>>> from sympy import MatrixSymbol, sqrt
>>> A = MatrixSymbol("A", 3, 3)
>>> _coeff_isneg(-sqrt(2)*A)
True
>>> _coeff_isneg(sqrt(2)*A)
False
"""
if a.is_MatMul:
a = a.args[0]
if a.is_Mul:
a = a.args[0]
return a.is_Number and a.is_extended_negative
class PoleError(Exception):
pass
class ArgumentIndexError(ValueError):
def __str__(self):
return ("Invalid operation with argument number %s for Function %s" %
(self.args[1], self.args[0]))
class BadSignatureError(TypeError):
'''Raised when a Lambda is created with an invalid signature'''
pass
class BadArgumentsError(TypeError):
'''Raised when a Lambda is called with an incorrect number of arguments'''
pass
# Python 3 version that does not raise a Deprecation warning
def arity(cls):
"""Return the arity of the function if it is known, else None.
Explanation
===========
When default values are specified for some arguments, they are
optional and the arity is reported as a tuple of possible values.
Examples
========
>>> from sympy import arity, log
>>> arity(lambda x: x)
1
>>> arity(log)
(1, 2)
>>> arity(lambda *x: sum(x)) is None
True
"""
eval_ = getattr(cls, 'eval', cls)
parameters = inspect.signature(eval_).parameters.items()
if [p for _, p in parameters if p.kind == p.VAR_POSITIONAL]:
return
p_or_k = [p for _, p in parameters if p.kind == p.POSITIONAL_OR_KEYWORD]
# how many have no default and how many have a default value
no, yes = map(len, sift(p_or_k,
lambda p:p.default == p.empty, binary=True))
return no if not yes else tuple(range(no, no + yes + 1))
class FunctionClass(type):
"""
Base class for function classes. FunctionClass is a subclass of type.
Use Function('<function name>' [ , signature ]) to create
undefined function classes.
"""
_new = type.__new__
def __init__(cls, *args, **kwargs):
# honor kwarg value or class-defined value before using
# the number of arguments in the eval function (if present)
nargs = kwargs.pop('nargs', cls.__dict__.get('nargs', arity(cls)))
if nargs is None and 'nargs' not in cls.__dict__:
for supcls in cls.__mro__:
if hasattr(supcls, '_nargs'):
nargs = supcls._nargs
break
else:
continue
# Canonicalize nargs here; change to set in nargs.
if is_sequence(nargs):
if not nargs:
raise ValueError(filldedent('''
Incorrectly specified nargs as %s:
if there are no arguments, it should be
`nargs = 0`;
if there are any number of arguments,
it should be
`nargs = None`''' % str(nargs)))
nargs = tuple(ordered(set(nargs)))
elif nargs is not None:
nargs = (as_int(nargs),)
cls._nargs = nargs
# When __init__ is called from UndefinedFunction it is called with
# just one arg but when it is called from subclassing Function it is
# called with the usual (name, bases, namespace) type() signature.
if len(args) == 3:
namespace = args[2]
if 'eval' in namespace and not isinstance(namespace['eval'], classmethod):
raise TypeError("eval on Function subclasses should be a class method (defined with @classmethod)")
@property
def __signature__(self):
"""
Allow Python 3's inspect.signature to give a useful signature for
Function subclasses.
"""
# Python 3 only, but backports (like the one in IPython) still might
# call this.
try:
from inspect import signature
except ImportError:
return None
# TODO: Look at nargs
return signature(self.eval)
@property
def free_symbols(self):
return set()
@property
def xreplace(self):
# Function needs args so we define a property that returns
# a function that takes args...and then use that function
# to return the right value
return lambda rule, **_: rule.get(self, self)
@property
def nargs(self):
"""Return a set of the allowed number of arguments for the function.
Examples
========
>>> from sympy import Function
>>> f = Function('f')
If the function can take any number of arguments, the set of whole
numbers is returned:
>>> Function('f').nargs
Naturals0
If the function was initialized to accept one or more arguments, a
corresponding set will be returned:
>>> Function('f', nargs=1).nargs
{1}
>>> Function('f', nargs=(2, 1)).nargs
{1, 2}
The undefined function, after application, also has the nargs
attribute; the actual number of arguments is always available by
checking the ``args`` attribute:
>>> f = Function('f')
>>> f(1).nargs
Naturals0
>>> len(f(1).args)
1
"""
from sympy.sets.sets import FiniteSet
# XXX it would be nice to handle this in __init__ but there are import
# problems with trying to import FiniteSet there
return FiniteSet(*self._nargs) if self._nargs else S.Naturals0
def _valid_nargs(self, n : int) -> bool:
""" Return True if the specified integer is a valid number of arguments
The number of arguments n is guaranteed to be an integer and positive
"""
if self._nargs:
return n in self._nargs
nargs = self.nargs
return nargs is S.Naturals0 or n in nargs
def __repr__(cls):
return cls.__name__
class Application(Basic, metaclass=FunctionClass):
"""
Base class for applied functions.
Explanation
===========
Instances of Application represent the result of applying an application of
any type to any object.
"""
is_Function = True
@cacheit
def __new__(cls, *args, **options):
from sympy.sets.fancysets import Naturals0
from sympy.sets.sets import FiniteSet
args = list(map(sympify, args))
evaluate = options.pop('evaluate', global_parameters.evaluate)
# WildFunction (and anything else like it) may have nargs defined
# and we throw that value away here
options.pop('nargs', None)
if options:
raise ValueError("Unknown options: %s" % options)
if evaluate:
evaluated = cls.eval(*args)
if evaluated is not None:
return evaluated
obj = super().__new__(cls, *args, **options)
# make nargs uniform here
sentinel = object()
objnargs = getattr(obj, "nargs", sentinel)
if objnargs is not sentinel:
# things passing through here:
# - functions subclassed from Function (e.g. myfunc(1).nargs)
# - functions like cos(1).nargs
# - AppliedUndef with given nargs like Function('f', nargs=1)(1).nargs
# Canonicalize nargs here
if is_sequence(objnargs):
nargs = tuple(ordered(set(objnargs)))
elif objnargs is not None:
nargs = (as_int(objnargs),)
else:
nargs = None
else:
# things passing through here:
# - WildFunction('f').nargs
# - AppliedUndef with no nargs like Function('f')(1).nargs
nargs = obj._nargs # note the underscore here
# convert to FiniteSet
obj.nargs = FiniteSet(*nargs) if nargs else Naturals0()
return obj
@classmethod
def eval(cls, *args):
"""
Returns a canonical form of cls applied to arguments args.
Explanation
===========
The ``eval()`` method is called when the class ``cls`` is about to be
instantiated and it should return either some simplified instance
(possible of some other class), or if the class ``cls`` should be
unmodified, return None.
Examples of ``eval()`` for the function "sign"
.. code-block:: python
@classmethod
def eval(cls, arg):
if arg is S.NaN:
return S.NaN
if arg.is_zero: return S.Zero
if arg.is_positive: return S.One
if arg.is_negative: return S.NegativeOne
if isinstance(arg, Mul):
coeff, terms = arg.as_coeff_Mul(rational=True)
if coeff is not S.One:
return cls(coeff) * cls(terms)
"""
return
@property
def func(self):
return self.__class__
def _eval_subs(self, old, new):
if (old.is_Function and new.is_Function and
callable(old) and callable(new) and
old == self.func and len(self.args) in new.nargs):
return new(*[i._subs(old, new) for i in self.args])
class Function(Application, Expr):
r"""
Base class for applied mathematical functions.
It also serves as a constructor for undefined function classes.
See the :ref:`custom-functions` guide for details on how to subclass
``Function`` and what methods can be defined.
Examples
========
**Undefined Functions**
To create an undefined function, pass a string of the function name to
``Function``.
>>> from sympy import Function, Symbol
>>> x = Symbol('x')
>>> f = Function('f')
>>> g = Function('g')(x)
>>> f
f
>>> f(x)
f(x)
>>> g
g(x)
>>> f(x).diff(x)
Derivative(f(x), x)
>>> g.diff(x)
Derivative(g(x), x)
Assumptions can be passed to ``Function`` the same as with a
:class:`~.Symbol`. Alternatively, you can use a ``Symbol`` with
assumptions for the function name and the function will inherit the name
and assumptions associated with the ``Symbol``:
>>> f_real = Function('f', real=True)
>>> f_real(x).is_real
True
>>> f_real_inherit = Function(Symbol('f', real=True))
>>> f_real_inherit(x).is_real
True
Note that assumptions on a function are unrelated to the assumptions on
the variables it is called on. If you want to add a relationship, subclass
``Function`` and define custom assumptions handler methods. See the
:ref:`custom-functions-assumptions` section of the :ref:`custom-functions`
guide for more details.
**Custom Function Subclasses**
The :ref:`custom-functions` guide has several
:ref:`custom-functions-complete-examples` of how to subclass ``Function``
to create a custom function.
"""
@property
def _diff_wrt(self):
return False
@cacheit
def __new__(cls, *args, **options):
# Handle calls like Function('f')
if cls is Function:
return UndefinedFunction(*args, **options)
n = len(args)
if not cls._valid_nargs(n):
# XXX: exception message must be in exactly this format to
# make it work with NumPy's functions like vectorize(). See,
# for example, https://github.com/numpy/numpy/issues/1697.
# The ideal solution would be just to attach metadata to
# the exception and change NumPy to take advantage of this.
temp = ('%(name)s takes %(qual)s %(args)s '
'argument%(plural)s (%(given)s given)')
raise TypeError(temp % {
'name': cls,
'qual': 'exactly' if len(cls.nargs) == 1 else 'at least',
'args': min(cls.nargs),
'plural': 's'*(min(cls.nargs) != 1),
'given': n})
evaluate = options.get('evaluate', global_parameters.evaluate)
result = super().__new__(cls, *args, **options)
if evaluate and isinstance(result, cls) and result.args:
_should_evalf = [cls._should_evalf(a) for a in result.args]
pr2 = min(_should_evalf)
if pr2 > 0:
pr = max(_should_evalf)
result = result.evalf(prec_to_dps(pr))
return _sympify(result)
@classmethod
def _should_evalf(cls, arg):
"""
Decide if the function should automatically evalf().
Explanation
===========
By default (in this implementation), this happens if (and only if) the
ARG is a floating point number (including complex numbers).
This function is used by __new__.
Returns the precision to evalf to, or -1 if it should not evalf.
"""
if arg.is_Float:
return arg._prec
if not arg.is_Add:
return -1
m = pure_complex(arg)
if m is None:
return -1
# the elements of m are of type Number, so have a _prec
return max(m[0]._prec, m[1]._prec)
@classmethod
def class_key(cls):
from sympy.sets.fancysets import Naturals0
funcs = {
'exp': 10,
'log': 11,
'sin': 20,
'cos': 21,
'tan': 22,
'cot': 23,
'sinh': 30,
'cosh': 31,
'tanh': 32,
'coth': 33,
'conjugate': 40,
're': 41,
'im': 42,
'arg': 43,
}
name = cls.__name__
try:
i = funcs[name]
except KeyError:
i = 0 if isinstance(cls.nargs, Naturals0) else 10000
return 4, i, name
def _eval_evalf(self, prec):
def _get_mpmath_func(fname):
"""Lookup mpmath function based on name"""
if isinstance(self, AppliedUndef):
# Shouldn't lookup in mpmath but might have ._imp_
return None
if not hasattr(mpmath, fname):
fname = MPMATH_TRANSLATIONS.get(fname, None)
if fname is None:
return None
return getattr(mpmath, fname)
_eval_mpmath = getattr(self, '_eval_mpmath', None)
if _eval_mpmath is None:
func = _get_mpmath_func(self.func.__name__)
args = self.args
else:
func, args = _eval_mpmath()
# Fall-back evaluation
if func is None:
imp = getattr(self, '_imp_', None)
if imp is None:
return None
try:
return Float(imp(*[i.evalf(prec) for i in self.args]), prec)
except (TypeError, ValueError):
return None
# Convert all args to mpf or mpc
# Convert the arguments to *higher* precision than requested for the
# final result.
# XXX + 5 is a guess, it is similar to what is used in evalf.py. Should
# we be more intelligent about it?
try:
args = [arg._to_mpmath(prec + 5) for arg in args]
def bad(m):
from mpmath import mpf, mpc
# the precision of an mpf value is the last element
# if that is 1 (and m[1] is not 1 which would indicate a
# power of 2), then the eval failed; so check that none of
# the arguments failed to compute to a finite precision.
# Note: An mpc value has two parts, the re and imag tuple;
# check each of those parts, too. Anything else is allowed to
# pass
if isinstance(m, mpf):
m = m._mpf_
return m[1] !=1 and m[-1] == 1
elif isinstance(m, mpc):
m, n = m._mpc_
return m[1] !=1 and m[-1] == 1 and \
n[1] !=1 and n[-1] == 1
else:
return False
if any(bad(a) for a in args):
raise ValueError # one or more args failed to compute with significance
except ValueError:
return
with mpmath.workprec(prec):
v = func(*args)
return Expr._from_mpmath(v, prec)
def _eval_derivative(self, s):
# f(x).diff(s) -> x.diff(s) * f.fdiff(1)(s)
i = 0
l = []
for a in self.args:
i += 1
da = a.diff(s)
if da.is_zero:
continue
try:
df = self.fdiff(i)
except ArgumentIndexError:
df = Function.fdiff(self, i)
l.append(df * da)
return Add(*l)
def _eval_is_commutative(self):
return fuzzy_and(a.is_commutative for a in self.args)
def _eval_is_meromorphic(self, x, a):
if not self.args:
return True
if any(arg.has(x) for arg in self.args[1:]):
return False
arg = self.args[0]
if not arg._eval_is_meromorphic(x, a):
return None
return fuzzy_not(type(self).is_singular(arg.subs(x, a)))
_singularities: FuzzyBool | tuple[Expr, ...] = None
@classmethod
def is_singular(cls, a):
"""
Tests whether the argument is an essential singularity
or a branch point, or the functions is non-holomorphic.
"""
ss = cls._singularities
if ss in (True, None, False):
return ss
return fuzzy_or(a.is_infinite if s is S.ComplexInfinity
else (a - s).is_zero for s in ss)
def as_base_exp(self):
"""
Returns the method as the 2-tuple (base, exponent).
"""
return self, S.One
def _eval_aseries(self, n, args0, x, logx):
"""
Compute an asymptotic expansion around args0, in terms of self.args.
This function is only used internally by _eval_nseries and should not
be called directly; derived classes can overwrite this to implement
asymptotic expansions.
"""
raise PoleError(filldedent('''
Asymptotic expansion of %s around %s is
not implemented.''' % (type(self), args0)))
def _eval_nseries(self, x, n, logx, cdir=0):
"""
This function does compute series for multivariate functions,
but the expansion is always in terms of *one* variable.
Examples
========
>>> from sympy import atan2
>>> from sympy.abc import x, y
>>> atan2(x, y).series(x, n=2)
atan2(0, y) + x/y + O(x**2)
>>> atan2(x, y).series(y, n=2)
-y/x + atan2(x, 0) + O(y**2)
This function also computes asymptotic expansions, if necessary
and possible:
>>> from sympy import loggamma
>>> loggamma(1/x)._eval_nseries(x,0,None)
-1/x - log(x)/x + log(x)/2 + O(1)
"""
from .symbol import uniquely_named_symbol
from sympy.series.order import Order
from sympy.sets.sets import FiniteSet
args = self.args
args0 = [t.limit(x, 0) for t in args]
if any(t.is_finite is False for t in args0):
from .numbers import oo, zoo, nan
a = [t.as_leading_term(x, logx=logx) for t in args]
a0 = [t.limit(x, 0) for t in a]
if any(t.has(oo, -oo, zoo, nan) for t in a0):
return self._eval_aseries(n, args0, x, logx)
# Careful: the argument goes to oo, but only logarithmically so. We
# are supposed to do a power series expansion "around the
# logarithmic term". e.g.
# f(1+x+log(x))
# -> f(1+logx) + x*f'(1+logx) + O(x**2)
# where 'logx' is given in the argument
a = [t._eval_nseries(x, n, logx) for t in args]
z = [r - r0 for (r, r0) in zip(a, a0)]
p = [Dummy() for _ in z]
q = []
v = None
for ai, zi, pi in zip(a0, z, p):
if zi.has(x):
if v is not None:
raise NotImplementedError
q.append(ai + pi)
v = pi
else:
q.append(ai)
e1 = self.func(*q)
if v is None:
return e1
s = e1._eval_nseries(v, n, logx)
o = s.getO()
s = s.removeO()
s = s.subs(v, zi).expand() + Order(o.expr.subs(v, zi), x)
return s
if (self.func.nargs is S.Naturals0
or (self.func.nargs == FiniteSet(1) and args0[0])
or any(c > 1 for c in self.func.nargs)):
e = self
e1 = e.expand()
if e == e1:
#for example when e = sin(x+1) or e = sin(cos(x))
#let's try the general algorithm
if len(e.args) == 1:
# issue 14411
e = e.func(e.args[0].cancel())
term = e.subs(x, S.Zero)
if term.is_finite is False or term is S.NaN:
raise PoleError("Cannot expand %s around 0" % (self))
series = term
fact = S.One
_x = uniquely_named_symbol('xi', self)
e = e.subs(x, _x)
for i in range(1, n):
fact *= Rational(i)
e = e.diff(_x)
subs = e.subs(_x, S.Zero)
if subs is S.NaN:
# try to evaluate a limit if we have to
subs = e.limit(_x, S.Zero)
if subs.is_finite is False:
raise PoleError("Cannot expand %s around 0" % (self))
term = subs*(x**i)/fact
term = term.expand()
series += term
return series + Order(x**n, x)
return e1.nseries(x, n=n, logx=logx)
arg = self.args[0]
l = []
g = None
# try to predict a number of terms needed
nterms = n + 2
cf = Order(arg.as_leading_term(x), x).getn()
if cf != 0:
nterms = (n/cf).ceiling()
for i in range(nterms):
g = self.taylor_term(i, arg, g)
g = g.nseries(x, n=n, logx=logx)
l.append(g)
return Add(*l) + Order(x**n, x)
def fdiff(self, argindex=1):
"""
Returns the first derivative of the function.
"""
if not (1 <= argindex <= len(self.args)):
raise ArgumentIndexError(self, argindex)
ix = argindex - 1
A = self.args[ix]
if A._diff_wrt:
if len(self.args) == 1 or not A.is_Symbol:
return _derivative_dispatch(self, A)
for i, v in enumerate(self.args):
if i != ix and A in v.free_symbols:
# it can't be in any other argument's free symbols
# issue 8510
break
else:
return _derivative_dispatch(self, A)
# See issue 4624 and issue 4719, 5600 and 8510
D = Dummy('xi_%i' % argindex, dummy_index=hash(A))
args = self.args[:ix] + (D,) + self.args[ix + 1:]
return Subs(Derivative(self.func(*args), D), D, A)
def _eval_as_leading_term(self, x, logx=None, cdir=0):
"""Stub that should be overridden by new Functions to return
the first non-zero term in a series if ever an x-dependent
argument whose leading term vanishes as x -> 0 might be encountered.
See, for example, cos._eval_as_leading_term.
"""
from sympy.series.order import Order
args = [a.as_leading_term(x, logx=logx) for a in self.args]
o = Order(1, x)
if any(x in a.free_symbols and o.contains(a) for a in args):
# Whereas x and any finite number are contained in O(1, x),
# expressions like 1/x are not. If any arg simplified to a
# vanishing expression as x -> 0 (like x or x**2, but not
# 3, 1/x, etc...) then the _eval_as_leading_term is needed
# to supply the first non-zero term of the series,
#
# e.g. expression leading term
# ---------- ------------
# cos(1/x) cos(1/x)
# cos(cos(x)) cos(1)
# cos(x) 1 <- _eval_as_leading_term needed
# sin(x) x <- _eval_as_leading_term needed
#
raise NotImplementedError(
'%s has no _eval_as_leading_term routine' % self.func)
else:
return self
class AppliedUndef(Function):
"""
Base class for expressions resulting from the application of an undefined
function.
"""
is_number = False
def __new__(cls, *args, **options):
args = list(map(sympify, args))
u = [a.name for a in args if isinstance(a, UndefinedFunction)]
if u:
raise TypeError('Invalid argument: expecting an expression, not UndefinedFunction%s: %s' % (
's'*(len(u) > 1), ', '.join(u)))
obj = super().__new__(cls, *args, **options)
return obj
def _eval_as_leading_term(self, x, logx=None, cdir=0):
return self
@property
def _diff_wrt(self):
"""
Allow derivatives wrt to undefined functions.
Examples
========
>>> from sympy import Function, Symbol
>>> f = Function('f')
>>> x = Symbol('x')
>>> f(x)._diff_wrt
True
>>> f(x).diff(x)
Derivative(f(x), x)
"""
return True
class UndefSageHelper:
"""
Helper to facilitate Sage conversion.
"""
def __get__(self, ins, typ):
import sage.all as sage
if ins is None:
return lambda: sage.function(typ.__name__)
else:
args = [arg._sage_() for arg in ins.args]
return lambda : sage.function(ins.__class__.__name__)(*args)
_undef_sage_helper = UndefSageHelper()
class UndefinedFunction(FunctionClass):
"""
The (meta)class of undefined functions.
"""
def __new__(mcl, name, bases=(AppliedUndef,), __dict__=None, **kwargs):
from .symbol import _filter_assumptions
# Allow Function('f', real=True)
# and/or Function(Symbol('f', real=True))
assumptions, kwargs = _filter_assumptions(kwargs)
if isinstance(name, Symbol):
assumptions = name._merge(assumptions)
name = name.name
elif not isinstance(name, str):
raise TypeError('expecting string or Symbol for name')
else:
commutative = assumptions.get('commutative', None)
assumptions = Symbol(name, **assumptions).assumptions0
if commutative is None:
assumptions.pop('commutative')
__dict__ = __dict__ or {}
# put the `is_*` for into __dict__
__dict__.update({'is_%s' % k: v for k, v in assumptions.items()})
# You can add other attributes, although they do have to be hashable
# (but seriously, if you want to add anything other than assumptions,
# just subclass Function)
__dict__.update(kwargs)
# add back the sanitized assumptions without the is_ prefix
kwargs.update(assumptions)
# Save these for __eq__
__dict__.update({'_kwargs': kwargs})
# do this for pickling
__dict__['__module__'] = None
obj = super().__new__(mcl, name, bases, __dict__)
obj.name = name
obj._sage_ = _undef_sage_helper
return obj
def __instancecheck__(cls, instance):
return cls in type(instance).__mro__
_kwargs: dict[str, bool | None] = {}
def __hash__(self):
return hash((self.class_key(), frozenset(self._kwargs.items())))
def __eq__(self, other):
return (isinstance(other, self.__class__) and
self.class_key() == other.class_key() and
self._kwargs == other._kwargs)
def __ne__(self, other):
return not self == other
@property
def _diff_wrt(self):
return False
# XXX: The type: ignore on WildFunction is because mypy complains:
#
# sympy/core/function.py:939: error: Cannot determine type of 'sort_key' in
# base class 'Expr'
#
# Somehow this is because of the @cacheit decorator but it is not clear how to
# fix it.
class WildFunction(Function, AtomicExpr): # type: ignore
"""
A WildFunction function matches any function (with its arguments).
Examples
========
>>> from sympy import WildFunction, Function, cos
>>> from sympy.abc import x, y
>>> F = WildFunction('F')
>>> f = Function('f')
>>> F.nargs
Naturals0
>>> x.match(F)
>>> F.match(F)
{F_: F_}
>>> f(x).match(F)
{F_: f(x)}
>>> cos(x).match(F)
{F_: cos(x)}
>>> f(x, y).match(F)
{F_: f(x, y)}
To match functions with a given number of arguments, set ``nargs`` to the
desired value at instantiation:
>>> F = WildFunction('F', nargs=2)
>>> F.nargs
{2}
>>> f(x).match(F)
>>> f(x, y).match(F)
{F_: f(x, y)}
To match functions with a range of arguments, set ``nargs`` to a tuple
containing the desired number of arguments, e.g. if ``nargs = (1, 2)``
then functions with 1 or 2 arguments will be matched.
>>> F = WildFunction('F', nargs=(1, 2))
>>> F.nargs
{1, 2}
>>> f(x).match(F)
{F_: f(x)}
>>> f(x, y).match(F)
{F_: f(x, y)}
>>> f(x, y, 1).match(F)
"""
# XXX: What is this class attribute used for?
include: set[Any] = set()
def __init__(cls, name, **assumptions):
from sympy.sets.sets import Set, FiniteSet
cls.name = name
nargs = assumptions.pop('nargs', S.Naturals0)
if not isinstance(nargs, Set):
# Canonicalize nargs here. See also FunctionClass.
if is_sequence(nargs):
nargs = tuple(ordered(set(nargs)))
elif nargs is not None:
nargs = (as_int(nargs),)
nargs = FiniteSet(*nargs)
cls.nargs = nargs
def matches(self, expr, repl_dict=None, old=False):
if not isinstance(expr, (AppliedUndef, Function)):
return None
if len(expr.args) not in self.nargs:
return None
if repl_dict is None:
repl_dict = {}
else:
repl_dict = repl_dict.copy()
repl_dict[self] = expr
return repl_dict
class Derivative(Expr):
"""
Carries out differentiation of the given expression with respect to symbols.
Examples
========
>>> from sympy import Derivative, Function, symbols, Subs
>>> from sympy.abc import x, y
>>> f, g = symbols('f g', cls=Function)
>>> Derivative(x**2, x, evaluate=True)
2*x
Denesting of derivatives retains the ordering of variables:
>>> Derivative(Derivative(f(x, y), y), x)
Derivative(f(x, y), y, x)
Contiguously identical symbols are merged into a tuple giving
the symbol and the count:
>>> Derivative(f(x), x, x, y, x)
Derivative(f(x), (x, 2), y, x)
If the derivative cannot be performed, and evaluate is True, the
order of the variables of differentiation will be made canonical:
>>> Derivative(f(x, y), y, x, evaluate=True)
Derivative(f(x, y), x, y)
Derivatives with respect to undefined functions can be calculated:
>>> Derivative(f(x)**2, f(x), evaluate=True)
2*f(x)
Such derivatives will show up when the chain rule is used to
evalulate a derivative:
>>> f(g(x)).diff(x)
Derivative(f(g(x)), g(x))*Derivative(g(x), x)
Substitution is used to represent derivatives of functions with
arguments that are not symbols or functions:
>>> f(2*x + 3).diff(x) == 2*Subs(f(y).diff(y), y, 2*x + 3)
True
Notes
=====
Simplification of high-order derivatives:
Because there can be a significant amount of simplification that can be
done when multiple differentiations are performed, results will be
automatically simplified in a fairly conservative fashion unless the
keyword ``simplify`` is set to False.
>>> from sympy import sqrt, diff, Function, symbols
>>> from sympy.abc import x, y, z
>>> f, g = symbols('f,g', cls=Function)
>>> e = sqrt((x + 1)**2 + x)
>>> diff(e, (x, 5), simplify=False).count_ops()
136
>>> diff(e, (x, 5)).count_ops()
30
Ordering of variables:
If evaluate is set to True and the expression cannot be evaluated, the
list of differentiation symbols will be sorted, that is, the expression is
assumed to have continuous derivatives up to the order asked.
Derivative wrt non-Symbols:
For the most part, one may not differentiate wrt non-symbols.
For example, we do not allow differentiation wrt `x*y` because
there are multiple ways of structurally defining where x*y appears
in an expression: a very strict definition would make
(x*y*z).diff(x*y) == 0. Derivatives wrt defined functions (like
cos(x)) are not allowed, either:
>>> (x*y*z).diff(x*y)
Traceback (most recent call last):
...
ValueError: Can't calculate derivative wrt x*y.
To make it easier to work with variational calculus, however,
derivatives wrt AppliedUndef and Derivatives are allowed.
For example, in the Euler-Lagrange method one may write
F(t, u, v) where u = f(t) and v = f'(t). These variables can be
written explicitly as functions of time::
>>> from sympy.abc import t
>>> F = Function('F')
>>> U = f(t)
>>> V = U.diff(t)
The derivative wrt f(t) can be obtained directly:
>>> direct = F(t, U, V).diff(U)
When differentiation wrt a non-Symbol is attempted, the non-Symbol
is temporarily converted to a Symbol while the differentiation
is performed and the same answer is obtained:
>>> indirect = F(t, U, V).subs(U, x).diff(x).subs(x, U)
>>> assert direct == indirect
The implication of this non-symbol replacement is that all
functions are treated as independent of other functions and the
symbols are independent of the functions that contain them::
>>> x.diff(f(x))
0
>>> g(x).diff(f(x))
0
It also means that derivatives are assumed to depend only
on the variables of differentiation, not on anything contained
within the expression being differentiated::
>>> F = f(x)
>>> Fx = F.diff(x)
>>> Fx.diff(F) # derivative depends on x, not F
0
>>> Fxx = Fx.diff(x)
>>> Fxx.diff(Fx) # derivative depends on x, not Fx
0
The last example can be made explicit by showing the replacement
of Fx in Fxx with y:
>>> Fxx.subs(Fx, y)
Derivative(y, x)
Since that in itself will evaluate to zero, differentiating
wrt Fx will also be zero:
>>> _.doit()
0
Replacing undefined functions with concrete expressions
One must be careful to replace undefined functions with expressions
that contain variables consistent with the function definition and
the variables of differentiation or else insconsistent result will
be obtained. Consider the following example:
>>> eq = f(x)*g(y)
>>> eq.subs(f(x), x*y).diff(x, y).doit()
y*Derivative(g(y), y) + g(y)
>>> eq.diff(x, y).subs(f(x), x*y).doit()
y*Derivative(g(y), y)
The results differ because `f(x)` was replaced with an expression
that involved both variables of differentiation. In the abstract
case, differentiation of `f(x)` by `y` is 0; in the concrete case,
the presence of `y` made that derivative nonvanishing and produced
the extra `g(y)` term.
Defining differentiation for an object
An object must define ._eval_derivative(symbol) method that returns
the differentiation result. This function only needs to consider the
non-trivial case where expr contains symbol and it should call the diff()
method internally (not _eval_derivative); Derivative should be the only
one to call _eval_derivative.
Any class can allow derivatives to be taken with respect to
itself (while indicating its scalar nature). See the
docstring of Expr._diff_wrt.
See Also
========
_sort_variable_count
"""
is_Derivative = True
@property
def _diff_wrt(self):
"""An expression may be differentiated wrt a Derivative if
it is in elementary form.
Examples
========
>>> from sympy import Function, Derivative, cos
>>> from sympy.abc import x
>>> f = Function('f')
>>> Derivative(f(x), x)._diff_wrt
True
>>> Derivative(cos(x), x)._diff_wrt
False
>>> Derivative(x + 1, x)._diff_wrt
False
A Derivative might be an unevaluated form of what will not be
a valid variable of differentiation if evaluated. For example,
>>> Derivative(f(f(x)), x).doit()
Derivative(f(x), x)*Derivative(f(f(x)), f(x))
Such an expression will present the same ambiguities as arise
when dealing with any other product, like ``2*x``, so ``_diff_wrt``
is False:
>>> Derivative(f(f(x)), x)._diff_wrt
False
"""
return self.expr._diff_wrt and isinstance(self.doit(), Derivative)
def __new__(cls, expr, *variables, **kwargs):
expr = sympify(expr)
symbols_or_none = getattr(expr, "free_symbols", None)
has_symbol_set = isinstance(symbols_or_none, set)
if not has_symbol_set:
raise ValueError(filldedent('''
Since there are no variables in the expression %s,
it cannot be differentiated.''' % expr))
# determine value for variables if it wasn't given
if not variables:
variables = expr.free_symbols
if len(variables) != 1:
if expr.is_number:
return S.Zero
if len(variables) == 0:
raise ValueError(filldedent('''
Since there are no variables in the expression,
the variable(s) of differentiation must be supplied
to differentiate %s''' % expr))
else:
raise ValueError(filldedent('''
Since there is more than one variable in the
expression, the variable(s) of differentiation
must be supplied to differentiate %s''' % expr))
# Split the list of variables into a list of the variables we are diff
# wrt, where each element of the list has the form (s, count) where
# s is the entity to diff wrt and count is the order of the
# derivative.
variable_count = []
array_likes = (tuple, list, Tuple)
from sympy.tensor.array import Array, NDimArray
for i, v in enumerate(variables):
if isinstance(v, UndefinedFunction):
raise TypeError(
"cannot differentiate wrt "
"UndefinedFunction: %s" % v)
if isinstance(v, array_likes):
if len(v) == 0:
# Ignore empty tuples: Derivative(expr, ... , (), ... )
continue
if isinstance(v[0], array_likes):
# Derive by array: Derivative(expr, ... , [[x, y, z]], ... )
if len(v) == 1:
v = Array(v[0])
count = 1
else:
v, count = v
v = Array(v)
else:
v, count = v
if count == 0:
continue
variable_count.append(Tuple(v, count))
continue
v = sympify(v)
if isinstance(v, Integer):
if i == 0:
raise ValueError("First variable cannot be a number: %i" % v)
count = v
prev, prevcount = variable_count[-1]
if prevcount != 1:
raise TypeError("tuple {} followed by number {}".format((prev, prevcount), v))
if count == 0:
variable_count.pop()
else:
variable_count[-1] = Tuple(prev, count)
else:
count = 1
variable_count.append(Tuple(v, count))
# light evaluation of contiguous, identical
# items: (x, 1), (x, 1) -> (x, 2)
merged = []
for t in variable_count:
v, c = t
if c.is_negative:
raise ValueError(
'order of differentiation must be nonnegative')
if merged and merged[-1][0] == v:
c += merged[-1][1]
if not c:
merged.pop()
else:
merged[-1] = Tuple(v, c)
else:
merged.append(t)
variable_count = merged
# sanity check of variables of differentation; we waited
# until the counts were computed since some variables may
# have been removed because the count was 0
for v, c in variable_count:
# v must have _diff_wrt True
if not v._diff_wrt:
__ = '' # filler to make error message neater
raise ValueError(filldedent('''
Can't calculate derivative wrt %s.%s''' % (v,
__)))
# We make a special case for 0th derivative, because there is no
# good way to unambiguously print this.
if len(variable_count) == 0:
return expr
evaluate = kwargs.get('evaluate', False)
if evaluate:
if isinstance(expr, Derivative):
expr = expr.canonical
variable_count = [
(v.canonical if isinstance(v, Derivative) else v, c)
for v, c in variable_count]
# Look for a quick exit if there are symbols that don't appear in
# expression at all. Note, this cannot check non-symbols like
# Derivatives as those can be created by intermediate
# derivatives.
zero = False
free = expr.free_symbols
from sympy.matrices.expressions.matexpr import MatrixExpr
for v, c in variable_count:
vfree = v.free_symbols
if c.is_positive and vfree:
if isinstance(v, AppliedUndef):
# these match exactly since
# x.diff(f(x)) == g(x).diff(f(x)) == 0
# and are not created by differentiation
D = Dummy()
if not expr.xreplace({v: D}).has(D):
zero = True
break
elif isinstance(v, MatrixExpr):
zero = False
break
elif isinstance(v, Symbol) and v not in free:
zero = True
break
else:
if not free & vfree:
# e.g. v is IndexedBase or Matrix
zero = True
break
if zero:
return cls._get_zero_with_shape_like(expr)
# make the order of symbols canonical
#TODO: check if assumption of discontinuous derivatives exist
variable_count = cls._sort_variable_count(variable_count)
# denest
if isinstance(expr, Derivative):
variable_count = list(expr.variable_count) + variable_count
expr = expr.expr
return _derivative_dispatch(expr, *variable_count, **kwargs)
# we return here if evaluate is False or if there is no
# _eval_derivative method
if not evaluate or not hasattr(expr, '_eval_derivative'):
# return an unevaluated Derivative
if evaluate and variable_count == [(expr, 1)] and expr.is_scalar:
# special hack providing evaluation for classes
# that have defined is_scalar=True but have no
# _eval_derivative defined
return S.One
return Expr.__new__(cls, expr, *variable_count)
# evaluate the derivative by calling _eval_derivative method
# of expr for each variable
# -------------------------------------------------------------
nderivs = 0 # how many derivatives were performed
unhandled = []
from sympy.matrices.matrixbase import MatrixBase
for i, (v, count) in enumerate(variable_count):
old_expr = expr
old_v = None
is_symbol = v.is_symbol or isinstance(v,
(Iterable, Tuple, MatrixBase, NDimArray))
if not is_symbol:
old_v = v
v = Dummy('xi')
expr = expr.xreplace({old_v: v})
# Derivatives and UndefinedFunctions are independent
# of all others
clashing = not (isinstance(old_v, (Derivative, AppliedUndef)))
if v not in expr.free_symbols and not clashing:
return expr.diff(v) # expr's version of 0
if not old_v.is_scalar and not hasattr(
old_v, '_eval_derivative'):
# special hack providing evaluation for classes
# that have defined is_scalar=True but have no
# _eval_derivative defined
expr *= old_v.diff(old_v)
obj = cls._dispatch_eval_derivative_n_times(expr, v, count)
if obj is not None and obj.is_zero:
return obj
nderivs += count
if old_v is not None:
if obj is not None:
# remove the dummy that was used
obj = obj.subs(v, old_v)
# restore expr
expr = old_expr
if obj is None:
# we've already checked for quick-exit conditions
# that give 0 so the remaining variables
# are contained in the expression but the expression
# did not compute a derivative so we stop taking
# derivatives
unhandled = variable_count[i:]
break
expr = obj
# what we have so far can be made canonical
expr = expr.replace(
lambda x: isinstance(x, Derivative),
lambda x: x.canonical)
if unhandled:
if isinstance(expr, Derivative):
unhandled = list(expr.variable_count) + unhandled
expr = expr.expr
expr = Expr.__new__(cls, expr, *unhandled)
if (nderivs > 1) == True and kwargs.get('simplify', True):
from .exprtools import factor_terms
from sympy.simplify.simplify import signsimp
expr = factor_terms(signsimp(expr))
return expr
@property
def canonical(cls):
return cls.func(cls.expr,
*Derivative._sort_variable_count(cls.variable_count))
@classmethod
def _sort_variable_count(cls, vc):
"""
Sort (variable, count) pairs into canonical order while
retaining order of variables that do not commute during
differentiation:
* symbols and functions commute with each other
* derivatives commute with each other
* a derivative does not commute with anything it contains
* any other object is not allowed to commute if it has
free symbols in common with another object
Examples
========
>>> from sympy import Derivative, Function, symbols
>>> vsort = Derivative._sort_variable_count
>>> x, y, z = symbols('x y z')
>>> f, g, h = symbols('f g h', cls=Function)
Contiguous items are collapsed into one pair:
>>> vsort([(x, 1), (x, 1)])
[(x, 2)]
>>> vsort([(y, 1), (f(x), 1), (y, 1), (f(x), 1)])
[(y, 2), (f(x), 2)]
Ordering is canonical.
>>> def vsort0(*v):
... # docstring helper to
... # change vi -> (vi, 0), sort, and return vi vals
... return [i[0] for i in vsort([(i, 0) for i in v])]
>>> vsort0(y, x)
[x, y]
>>> vsort0(g(y), g(x), f(y))
[f(y), g(x), g(y)]
Symbols are sorted as far to the left as possible but never
move to the left of a derivative having the same symbol in
its variables; the same applies to AppliedUndef which are
always sorted after Symbols:
>>> dfx = f(x).diff(x)
>>> assert vsort0(dfx, y) == [y, dfx]
>>> assert vsort0(dfx, x) == [dfx, x]
"""
if not vc:
return []
vc = list(vc)
if len(vc) == 1:
return [Tuple(*vc[0])]
V = list(range(len(vc)))
E = []
v = lambda i: vc[i][0]
D = Dummy()
def _block(d, v, wrt=False):
# return True if v should not come before d else False
if d == v:
return wrt
if d.is_Symbol:
return False
if isinstance(d, Derivative):
# a derivative blocks if any of it's variables contain
# v; the wrt flag will return True for an exact match
# and will cause an AppliedUndef to block if v is in
# the arguments
if any(_block(k, v, wrt=True)
for k in d._wrt_variables):
return True
return False
if not wrt and isinstance(d, AppliedUndef):
return False
if v.is_Symbol:
return v in d.free_symbols
if isinstance(v, AppliedUndef):
return _block(d.xreplace({v: D}), D)
return d.free_symbols & v.free_symbols
for i in range(len(vc)):
for j in range(i):
if _block(v(j), v(i)):
E.append((j,i))
# this is the default ordering to use in case of ties
O = dict(zip(ordered(uniq([i for i, c in vc])), range(len(vc))))
ix = topological_sort((V, E), key=lambda i: O[v(i)])
# merge counts of contiguously identical items
merged = []
for v, c in [vc[i] for i in ix]:
if merged and merged[-1][0] == v:
merged[-1][1] += c
else:
merged.append([v, c])
return [Tuple(*i) for i in merged]
def _eval_is_commutative(self):
return self.expr.is_commutative
def _eval_derivative(self, v):
# If v (the variable of differentiation) is not in
# self.variables, we might be able to take the derivative.
if v not in self._wrt_variables:
dedv = self.expr.diff(v)
if isinstance(dedv, Derivative):
return dedv.func(dedv.expr, *(self.variable_count + dedv.variable_count))
# dedv (d(self.expr)/dv) could have simplified things such that the
# derivative wrt things in self.variables can now be done. Thus,
# we set evaluate=True to see if there are any other derivatives
# that can be done. The most common case is when dedv is a simple
# number so that the derivative wrt anything else will vanish.
return self.func(dedv, *self.variables, evaluate=True)
# In this case v was in self.variables so the derivative wrt v has
# already been attempted and was not computed, either because it
# couldn't be or evaluate=False originally.
variable_count = list(self.variable_count)
variable_count.append((v, 1))
return self.func(self.expr, *variable_count, evaluate=False)
def doit(self, **hints):
expr = self.expr
if hints.get('deep', True):
expr = expr.doit(**hints)
hints['evaluate'] = True
rv = self.func(expr, *self.variable_count, **hints)
if rv!= self and rv.has(Derivative):
rv = rv.doit(**hints)
return rv
@_sympifyit('z0', NotImplementedError)
def doit_numerically(self, z0):
"""
Evaluate the derivative at z numerically.
When we can represent derivatives at a point, this should be folded
into the normal evalf. For now, we need a special method.
"""
if len(self.free_symbols) != 1 or len(self.variables) != 1:
raise NotImplementedError('partials and higher order derivatives')
z = list(self.free_symbols)[0]
def eval(x):
f0 = self.expr.subs(z, Expr._from_mpmath(x, prec=mpmath.mp.prec))
f0 = f0.evalf(prec_to_dps(mpmath.mp.prec))
return f0._to_mpmath(mpmath.mp.prec)
return Expr._from_mpmath(mpmath.diff(eval,
z0._to_mpmath(mpmath.mp.prec)),
mpmath.mp.prec)
@property
def expr(self):
return self._args[0]
@property
def _wrt_variables(self):
# return the variables of differentiation without
# respect to the type of count (int or symbolic)
return [i[0] for i in self.variable_count]
@property
def variables(self):
# TODO: deprecate? YES, make this 'enumerated_variables' and
# name _wrt_variables as variables
# TODO: support for `d^n`?
rv = []
for v, count in self.variable_count:
if not count.is_Integer:
raise TypeError(filldedent('''
Cannot give expansion for symbolic count. If you just
want a list of all variables of differentiation, use
_wrt_variables.'''))
rv.extend([v]*count)
return tuple(rv)
@property
def variable_count(self):
return self._args[1:]
@property
def derivative_count(self):
return sum([count for _, count in self.variable_count], 0)
@property
def free_symbols(self):
ret = self.expr.free_symbols
# Add symbolic counts to free_symbols
for _, count in self.variable_count:
ret.update(count.free_symbols)
return ret
@property
def kind(self):
return self.args[0].kind
def _eval_subs(self, old, new):
# The substitution (old, new) cannot be done inside
# Derivative(expr, vars) for a variety of reasons
# as handled below.
if old in self._wrt_variables:
# first handle the counts
expr = self.func(self.expr, *[(v, c.subs(old, new))
for v, c in self.variable_count])
if expr != self:
return expr._eval_subs(old, new)
# quick exit case
if not getattr(new, '_diff_wrt', False):
# case (0): new is not a valid variable of
# differentiation
if isinstance(old, Symbol):
# don't introduce a new symbol if the old will do
return Subs(self, old, new)
else:
xi = Dummy('xi')
return Subs(self.xreplace({old: xi}), xi, new)
# If both are Derivatives with the same expr, check if old is
# equivalent to self or if old is a subderivative of self.
if old.is_Derivative and old.expr == self.expr:
if self.canonical == old.canonical:
return new
# collections.Counter doesn't have __le__
def _subset(a, b):
return all((a[i] <= b[i]) == True for i in a)
old_vars = Counter(dict(reversed(old.variable_count)))
self_vars = Counter(dict(reversed(self.variable_count)))
if _subset(old_vars, self_vars):
return _derivative_dispatch(new, *(self_vars - old_vars).items()).canonical
args = list(self.args)
newargs = [x._subs(old, new) for x in args]
if args[0] == old:
# complete replacement of self.expr
# we already checked that the new is valid so we know
# it won't be a problem should it appear in variables
return _derivative_dispatch(*newargs)
if newargs[0] != args[0]:
# case (1) can't change expr by introducing something that is in
# the _wrt_variables if it was already in the expr
# e.g.
# for Derivative(f(x, g(y)), y), x cannot be replaced with
# anything that has y in it; for f(g(x), g(y)).diff(g(y))
# g(x) cannot be replaced with anything that has g(y)
syms = {vi: Dummy() for vi in self._wrt_variables
if not vi.is_Symbol}
wrt = {syms.get(vi, vi) for vi in self._wrt_variables}
forbidden = args[0].xreplace(syms).free_symbols & wrt
nfree = new.xreplace(syms).free_symbols
ofree = old.xreplace(syms).free_symbols
if (nfree - ofree) & forbidden:
return Subs(self, old, new)
viter = ((i, j) for ((i, _), (j, _)) in zip(newargs[1:], args[1:]))
if any(i != j for i, j in viter): # a wrt-variable change
# case (2) can't change vars by introducing a variable
# that is contained in expr, e.g.
# for Derivative(f(z, g(h(x), y)), y), y cannot be changed to
# x, h(x), or g(h(x), y)
for a in _atomic(self.expr, recursive=True):
for i in range(1, len(newargs)):
vi, _ = newargs[i]
if a == vi and vi != args[i][0]:
return Subs(self, old, new)
# more arg-wise checks
vc = newargs[1:]
oldv = self._wrt_variables
newe = self.expr
subs = []
for i, (vi, ci) in enumerate(vc):
if not vi._diff_wrt:
# case (3) invalid differentiation expression so
# create a replacement dummy
xi = Dummy('xi_%i' % i)
# replace the old valid variable with the dummy
# in the expression
newe = newe.xreplace({oldv[i]: xi})
# and replace the bad variable with the dummy
vc[i] = (xi, ci)
# and record the dummy with the new (invalid)
# differentiation expression
subs.append((xi, vi))
if subs:
# handle any residual substitution in the expression
newe = newe._subs(old, new)
# return the Subs-wrapped derivative
return Subs(Derivative(newe, *vc), *zip(*subs))
# everything was ok
return _derivative_dispatch(*newargs)
def _eval_lseries(self, x, logx, cdir=0):
dx = self.variables
for term in self.expr.lseries(x, logx=logx, cdir=cdir):
yield self.func(term, *dx)
def _eval_nseries(self, x, n, logx, cdir=0):
arg = self.expr.nseries(x, n=n, logx=logx)
o = arg.getO()
dx = self.variables
rv = [self.func(a, *dx) for a in Add.make_args(arg.removeO())]
if o:
rv.append(o/x)
return Add(*rv)
def _eval_as_leading_term(self, x, logx=None, cdir=0):
series_gen = self.expr.lseries(x)
d = S.Zero
for leading_term in series_gen:
d = diff(leading_term, *self.variables)
if d != 0:
break
return d
def as_finite_difference(self, points=1, x0=None, wrt=None):
""" Expresses a Derivative instance as a finite difference.
Parameters
==========
points : sequence or coefficient, optional
If sequence: discrete values (length >= order+1) of the
independent variable used for generating the finite
difference weights.
If it is a coefficient, it will be used as the step-size
for generating an equidistant sequence of length order+1
centered around ``x0``. Default: 1 (step-size 1)
x0 : number or Symbol, optional
the value of the independent variable (``wrt``) at which the
derivative is to be approximated. Default: same as ``wrt``.
wrt : Symbol, optional
"with respect to" the variable for which the (partial)
derivative is to be approximated for. If not provided it
is required that the derivative is ordinary. Default: ``None``.
Examples
========
>>> from sympy import symbols, Function, exp, sqrt, Symbol
>>> x, h = symbols('x h')
>>> f = Function('f')
>>> f(x).diff(x).as_finite_difference()
-f(x - 1/2) + f(x + 1/2)
The default step size and number of points are 1 and
``order + 1`` respectively. We can change the step size by
passing a symbol as a parameter:
>>> f(x).diff(x).as_finite_difference(h)
-f(-h/2 + x)/h + f(h/2 + x)/h
We can also specify the discretized values to be used in a
sequence:
>>> f(x).diff(x).as_finite_difference([x, x+h, x+2*h])
-3*f(x)/(2*h) + 2*f(h + x)/h - f(2*h + x)/(2*h)
The algorithm is not restricted to use equidistant spacing, nor
do we need to make the approximation around ``x0``, but we can get
an expression estimating the derivative at an offset:
>>> e, sq2 = exp(1), sqrt(2)
>>> xl = [x-h, x+h, x+e*h]
>>> f(x).diff(x, 1).as_finite_difference(xl, x+h*sq2) # doctest: +ELLIPSIS
2*h*((h + sqrt(2)*h)/(2*h) - (-sqrt(2)*h + h)/(2*h))*f(E*h + x)/...
To approximate ``Derivative`` around ``x0`` using a non-equidistant
spacing step, the algorithm supports assignment of undefined
functions to ``points``:
>>> dx = Function('dx')
>>> f(x).diff(x).as_finite_difference(points=dx(x), x0=x-h)
-f(-h + x - dx(-h + x)/2)/dx(-h + x) + f(-h + x + dx(-h + x)/2)/dx(-h + x)
Partial derivatives are also supported:
>>> y = Symbol('y')
>>> d2fdxdy=f(x,y).diff(x,y)
>>> d2fdxdy.as_finite_difference(wrt=x)
-Derivative(f(x - 1/2, y), y) + Derivative(f(x + 1/2, y), y)
We can apply ``as_finite_difference`` to ``Derivative`` instances in
compound expressions using ``replace``:
>>> (1 + 42**f(x).diff(x)).replace(lambda arg: arg.is_Derivative,
... lambda arg: arg.as_finite_difference())
42**(-f(x - 1/2) + f(x + 1/2)) + 1
See also
========
sympy.calculus.finite_diff.apply_finite_diff
sympy.calculus.finite_diff.differentiate_finite
sympy.calculus.finite_diff.finite_diff_weights
"""
from sympy.calculus.finite_diff import _as_finite_diff
return _as_finite_diff(self, points, x0, wrt)
@classmethod
def _get_zero_with_shape_like(cls, expr):
return S.Zero
@classmethod
def _dispatch_eval_derivative_n_times(cls, expr, v, count):
# Evaluate the derivative `n` times. If
# `_eval_derivative_n_times` is not overridden by the current
# object, the default in `Basic` will call a loop over
# `_eval_derivative`:
return expr._eval_derivative_n_times(v, count)
def _derivative_dispatch(expr, *variables, **kwargs):
from sympy.matrices.matrixbase import MatrixBase
from sympy.matrices.expressions.matexpr import MatrixExpr
from sympy.tensor.array import NDimArray
array_types = (MatrixBase, MatrixExpr, NDimArray, list, tuple, Tuple)
if isinstance(expr, array_types) or any(isinstance(i[0], array_types) if isinstance(i, (tuple, list, Tuple)) else isinstance(i, array_types) for i in variables):
from sympy.tensor.array.array_derivatives import ArrayDerivative
return ArrayDerivative(expr, *variables, **kwargs)
return Derivative(expr, *variables, **kwargs)
class Lambda(Expr):
"""
Lambda(x, expr) represents a lambda function similar to Python's
'lambda x: expr'. A function of several variables is written as
Lambda((x, y, ...), expr).
Examples
========
A simple example:
>>> from sympy import Lambda
>>> from sympy.abc import x
>>> f = Lambda(x, x**2)
>>> f(4)
16
For multivariate functions, use:
>>> from sympy.abc import y, z, t
>>> f2 = Lambda((x, y, z, t), x + y**z + t**z)
>>> f2(1, 2, 3, 4)
73
It is also possible to unpack tuple arguments:
>>> f = Lambda(((x, y), z), x + y + z)
>>> f((1, 2), 3)
6
A handy shortcut for lots of arguments:
>>> p = x, y, z
>>> f = Lambda(p, x + y*z)
>>> f(*p)
x + y*z
"""
is_Function = True
def __new__(cls, signature, expr):
if iterable(signature) and not isinstance(signature, (tuple, Tuple)):
sympy_deprecation_warning(
"""
Using a non-tuple iterable as the first argument to Lambda
is deprecated. Use Lambda(tuple(args), expr) instead.
""",
deprecated_since_version="1.5",
active_deprecations_target="deprecated-non-tuple-lambda",
)
signature = tuple(signature)
sig = signature if iterable(signature) else (signature,)
sig = sympify(sig)
cls._check_signature(sig)
if len(sig) == 1 and sig[0] == expr:
return S.IdentityFunction
return Expr.__new__(cls, sig, sympify(expr))
@classmethod
def _check_signature(cls, sig):
syms = set()
def rcheck(args):
for a in args:
if a.is_symbol:
if a in syms:
raise BadSignatureError("Duplicate symbol %s" % a)
syms.add(a)
elif isinstance(a, Tuple):
rcheck(a)
else:
raise BadSignatureError("Lambda signature should be only tuples"
" and symbols, not %s" % a)
if not isinstance(sig, Tuple):
raise BadSignatureError("Lambda signature should be a tuple not %s" % sig)
# Recurse through the signature:
rcheck(sig)
@property
def signature(self):
"""The expected form of the arguments to be unpacked into variables"""
return self._args[0]
@property
def expr(self):
"""The return value of the function"""
return self._args[1]
@property
def variables(self):
"""The variables used in the internal representation of the function"""
def _variables(args):
if isinstance(args, Tuple):
for arg in args:
yield from _variables(arg)
else:
yield args
return tuple(_variables(self.signature))
@property
def nargs(self):
from sympy.sets.sets import FiniteSet
return FiniteSet(len(self.signature))
bound_symbols = variables
@property
def free_symbols(self):
return self.expr.free_symbols - set(self.variables)
def __call__(self, *args):
n = len(args)
if n not in self.nargs: # Lambda only ever has 1 value in nargs
# XXX: exception message must be in exactly this format to
# make it work with NumPy's functions like vectorize(). See,
# for example, https://github.com/numpy/numpy/issues/1697.
# The ideal solution would be just to attach metadata to
# the exception and change NumPy to take advantage of this.
## XXX does this apply to Lambda? If not, remove this comment.
temp = ('%(name)s takes exactly %(args)s '
'argument%(plural)s (%(given)s given)')
raise BadArgumentsError(temp % {
'name': self,
'args': list(self.nargs)[0],
'plural': 's'*(list(self.nargs)[0] != 1),
'given': n})
d = self._match_signature(self.signature, args)
return self.expr.xreplace(d)
def _match_signature(self, sig, args):
symargmap = {}
def rmatch(pars, args):
for par, arg in zip(pars, args):
if par.is_symbol:
symargmap[par] = arg
elif isinstance(par, Tuple):
if not isinstance(arg, (tuple, Tuple)) or len(args) != len(pars):
raise BadArgumentsError("Can't match %s and %s" % (args, pars))
rmatch(par, arg)
rmatch(sig, args)
return symargmap
@property
def is_identity(self):
"""Return ``True`` if this ``Lambda`` is an identity function. """
return self.signature == self.expr
def _eval_evalf(self, prec):
return self.func(self.args[0], self.args[1].evalf(n=prec_to_dps(prec)))
class Subs(Expr):
"""
Represents unevaluated substitutions of an expression.
``Subs(expr, x, x0)`` represents the expression resulting
from substituting x with x0 in expr.
Parameters
==========
expr : Expr
An expression.
x : tuple, variable
A variable or list of distinct variables.
x0 : tuple or list of tuples
A point or list of evaluation points
corresponding to those variables.
Examples
========
>>> from sympy import Subs, Function, sin, cos
>>> from sympy.abc import x, y, z
>>> f = Function('f')
Subs are created when a particular substitution cannot be made. The
x in the derivative cannot be replaced with 0 because 0 is not a
valid variables of differentiation:
>>> f(x).diff(x).subs(x, 0)
Subs(Derivative(f(x), x), x, 0)
Once f is known, the derivative and evaluation at 0 can be done:
>>> _.subs(f, sin).doit() == sin(x).diff(x).subs(x, 0) == cos(0)
True
Subs can also be created directly with one or more variables:
>>> Subs(f(x)*sin(y) + z, (x, y), (0, 1))
Subs(z + f(x)*sin(y), (x, y), (0, 1))
>>> _.doit()
z + f(0)*sin(1)
Notes
=====
``Subs`` objects are generally useful to represent unevaluated derivatives
calculated at a point.
The variables may be expressions, but they are subjected to the limitations
of subs(), so it is usually a good practice to use only symbols for
variables, since in that case there can be no ambiguity.
There's no automatic expansion - use the method .doit() to effect all
possible substitutions of the object and also of objects inside the
expression.
When evaluating derivatives at a point that is not a symbol, a Subs object
is returned. One is also able to calculate derivatives of Subs objects - in
this case the expression is always expanded (for the unevaluated form, use
Derivative()).
In order to allow expressions to combine before doit is done, a
representation of the Subs expression is used internally to make
expressions that are superficially different compare the same:
>>> a, b = Subs(x, x, 0), Subs(y, y, 0)
>>> a + b
2*Subs(x, x, 0)
This can lead to unexpected consequences when using methods
like `has` that are cached:
>>> s = Subs(x, x, 0)
>>> s.has(x), s.has(y)
(True, False)
>>> ss = s.subs(x, y)
>>> ss.has(x), ss.has(y)
(True, False)
>>> s, ss
(Subs(x, x, 0), Subs(y, y, 0))
"""
def __new__(cls, expr, variables, point, **assumptions):
if not is_sequence(variables, Tuple):
variables = [variables]
variables = Tuple(*variables)
if has_dups(variables):
repeated = [str(v) for v, i in Counter(variables).items() if i > 1]
__ = ', '.join(repeated)
raise ValueError(filldedent('''
The following expressions appear more than once: %s
''' % __))
point = Tuple(*(point if is_sequence(point, Tuple) else [point]))
if len(point) != len(variables):
raise ValueError('Number of point values must be the same as '
'the number of variables.')
if not point:
return sympify(expr)
# denest
if isinstance(expr, Subs):
variables = expr.variables + variables
point = expr.point + point
expr = expr.expr
else:
expr = sympify(expr)
# use symbols with names equal to the point value (with prepended _)
# to give a variable-independent expression
pre = "_"
pts = sorted(set(point), key=default_sort_key)
from sympy.printing.str import StrPrinter
class CustomStrPrinter(StrPrinter):
def _print_Dummy(self, expr):
return str(expr) + str(expr.dummy_index)
def mystr(expr, **settings):
p = CustomStrPrinter(settings)
return p.doprint(expr)
while 1:
s_pts = {p: Symbol(pre + mystr(p)) for p in pts}
reps = [(v, s_pts[p])
for v, p in zip(variables, point)]
# if any underscore-prepended symbol is already a free symbol
# and is a variable with a different point value, then there
# is a clash, e.g. _0 clashes in Subs(_0 + _1, (_0, _1), (1, 0))
# because the new symbol that would be created is _1 but _1
# is already mapped to 0 so __0 and __1 are used for the new
# symbols
if any(r in expr.free_symbols and
r in variables and
Symbol(pre + mystr(point[variables.index(r)])) != r
for _, r in reps):
pre += "_"
continue
break
obj = Expr.__new__(cls, expr, Tuple(*variables), point)
obj._expr = expr.xreplace(dict(reps))
return obj
def _eval_is_commutative(self):
return self.expr.is_commutative
def doit(self, **hints):
e, v, p = self.args
# remove self mappings
for i, (vi, pi) in enumerate(zip(v, p)):
if vi == pi:
v = v[:i] + v[i + 1:]
p = p[:i] + p[i + 1:]
if not v:
return self.expr
if isinstance(e, Derivative):
# apply functions first, e.g. f -> cos
undone = []
for i, vi in enumerate(v):
if isinstance(vi, FunctionClass):
e = e.subs(vi, p[i])
else:
undone.append((vi, p[i]))
if not isinstance(e, Derivative):
e = e.doit()
if isinstance(e, Derivative):
# do Subs that aren't related to differentiation
undone2 = []
D = Dummy()
arg = e.args[0]
for vi, pi in undone:
if D not in e.xreplace({vi: D}).free_symbols:
if arg.has(vi):
e = e.subs(vi, pi)
else:
undone2.append((vi, pi))
undone = undone2
# differentiate wrt variables that are present
wrt = []
D = Dummy()
expr = e.expr
free = expr.free_symbols
for vi, ci in e.variable_count:
if isinstance(vi, Symbol) and vi in free:
expr = expr.diff((vi, ci))
elif D in expr.subs(vi, D).free_symbols:
expr = expr.diff((vi, ci))
else:
wrt.append((vi, ci))
# inject remaining subs
rv = expr.subs(undone)
# do remaining differentiation *in order given*
for vc in wrt:
rv = rv.diff(vc)
else:
# inject remaining subs
rv = e.subs(undone)
else:
rv = e.doit(**hints).subs(list(zip(v, p)))
if hints.get('deep', True) and rv != self:
rv = rv.doit(**hints)
return rv
def evalf(self, prec=None, **options):
return self.doit().evalf(prec, **options)
n = evalf # type:ignore
@property
def variables(self):
"""The variables to be evaluated"""
return self._args[1]
bound_symbols = variables
@property
def expr(self):
"""The expression on which the substitution operates"""
return self._args[0]
@property
def point(self):
"""The values for which the variables are to be substituted"""
return self._args[2]
@property
def free_symbols(self):
return (self.expr.free_symbols - set(self.variables) |
set(self.point.free_symbols))
@property
def expr_free_symbols(self):
sympy_deprecation_warning("""
The expr_free_symbols property is deprecated. Use free_symbols to get
the free symbols of an expression.
""",
deprecated_since_version="1.9",
active_deprecations_target="deprecated-expr-free-symbols")
# Don't show the warning twice from the recursive call
with ignore_warnings(SymPyDeprecationWarning):
return (self.expr.expr_free_symbols - set(self.variables) |
set(self.point.expr_free_symbols))
def __eq__(self, other):
if not isinstance(other, Subs):
return False
return self._hashable_content() == other._hashable_content()
def __ne__(self, other):
return not(self == other)
def __hash__(self):
return super().__hash__()
def _hashable_content(self):
return (self._expr.xreplace(self.canonical_variables),
) + tuple(ordered([(v, p) for v, p in
zip(self.variables, self.point) if not self.expr.has(v)]))
def _eval_subs(self, old, new):
# Subs doit will do the variables in order; the semantics
# of subs for Subs is have the following invariant for
# Subs object foo:
# foo.doit().subs(reps) == foo.subs(reps).doit()
pt = list(self.point)
if old in self.variables:
if _atomic(new) == {new} and not any(
i.has(new) for i in self.args):
# the substitution is neutral
return self.xreplace({old: new})
# any occurrence of old before this point will get
# handled by replacements from here on
i = self.variables.index(old)
for j in range(i, len(self.variables)):
pt[j] = pt[j]._subs(old, new)
return self.func(self.expr, self.variables, pt)
v = [i._subs(old, new) for i in self.variables]
if v != list(self.variables):
return self.func(self.expr, self.variables + (old,), pt + [new])
expr = self.expr._subs(old, new)
pt = [i._subs(old, new) for i in self.point]
return self.func(expr, v, pt)
def _eval_derivative(self, s):
# Apply the chain rule of the derivative on the substitution variables:
f = self.expr
vp = V, P = self.variables, self.point
val = Add.fromiter(p.diff(s)*Subs(f.diff(v), *vp).doit()
for v, p in zip(V, P))
# these are all the free symbols in the expr
efree = f.free_symbols
# some symbols like IndexedBase include themselves and args
# as free symbols
compound = {i for i in efree if len(i.free_symbols) > 1}
# hide them and see what independent free symbols remain
dums = {Dummy() for i in compound}
masked = f.xreplace(dict(zip(compound, dums)))
ifree = masked.free_symbols - dums
# include the compound symbols
free = ifree | compound
# remove the variables already handled
free -= set(V)
# add back any free symbols of remaining compound symbols
free |= {i for j in free & compound for i in j.free_symbols}
# if symbols of s are in free then there is more to do
if free & s.free_symbols:
val += Subs(f.diff(s), self.variables, self.point).doit()
return val
def _eval_nseries(self, x, n, logx, cdir=0):
if x in self.point:
# x is the variable being substituted into
apos = self.point.index(x)
other = self.variables[apos]
else:
other = x
arg = self.expr.nseries(other, n=n, logx=logx)
o = arg.getO()
terms = Add.make_args(arg.removeO())
rv = Add(*[self.func(a, *self.args[1:]) for a in terms])
if o:
rv += o.subs(other, x)
return rv
def _eval_as_leading_term(self, x, logx=None, cdir=0):
if x in self.point:
ipos = self.point.index(x)
xvar = self.variables[ipos]
return self.expr.as_leading_term(xvar)
if x in self.variables:
# if `x` is a dummy variable, it means it won't exist after the
# substitution has been performed:
return self
# The variable is independent of the substitution:
return self.expr.as_leading_term(x)
def diff(f, *symbols, **kwargs):
"""
Differentiate f with respect to symbols.
Explanation
===========
This is just a wrapper to unify .diff() and the Derivative class; its
interface is similar to that of integrate(). You can use the same
shortcuts for multiple variables as with Derivative. For example,
diff(f(x), x, x, x) and diff(f(x), x, 3) both return the third derivative
of f(x).
You can pass evaluate=False to get an unevaluated Derivative class. Note
that if there are 0 symbols (such as diff(f(x), x, 0), then the result will
be the function (the zeroth derivative), even if evaluate=False.
Examples
========
>>> from sympy import sin, cos, Function, diff
>>> from sympy.abc import x, y
>>> f = Function('f')
>>> diff(sin(x), x)
cos(x)
>>> diff(f(x), x, x, x)
Derivative(f(x), (x, 3))
>>> diff(f(x), x, 3)
Derivative(f(x), (x, 3))
>>> diff(sin(x)*cos(y), x, 2, y, 2)
sin(x)*cos(y)
>>> type(diff(sin(x), x))
cos
>>> type(diff(sin(x), x, evaluate=False))
<class 'sympy.core.function.Derivative'>
>>> type(diff(sin(x), x, 0))
sin
>>> type(diff(sin(x), x, 0, evaluate=False))
sin
>>> diff(sin(x))
cos(x)
>>> diff(sin(x*y))
Traceback (most recent call last):
...
ValueError: specify differentiation variables to differentiate sin(x*y)
Note that ``diff(sin(x))`` syntax is meant only for convenience
in interactive sessions and should be avoided in library code.
References
==========
.. [1] https://reference.wolfram.com/legacy/v5_2/Built-inFunctions/AlgebraicComputation/Calculus/D.html
See Also
========
Derivative
idiff: computes the derivative implicitly
"""
if hasattr(f, 'diff'):
return f.diff(*symbols, **kwargs)
kwargs.setdefault('evaluate', True)
return _derivative_dispatch(f, *symbols, **kwargs)
def expand(e, deep=True, modulus=None, power_base=True, power_exp=True,
mul=True, log=True, multinomial=True, basic=True, **hints):
r"""
Expand an expression using methods given as hints.
Explanation
===========
Hints evaluated unless explicitly set to False are: ``basic``, ``log``,
``multinomial``, ``mul``, ``power_base``, and ``power_exp`` The following
hints are supported but not applied unless set to True: ``complex``,
``func``, and ``trig``. In addition, the following meta-hints are
supported by some or all of the other hints: ``frac``, ``numer``,
``denom``, ``modulus``, and ``force``. ``deep`` is supported by all
hints. Additionally, subclasses of Expr may define their own hints or
meta-hints.
The ``basic`` hint is used for any special rewriting of an object that
should be done automatically (along with the other hints like ``mul``)
when expand is called. This is a catch-all hint to handle any sort of
expansion that may not be described by the existing hint names. To use
this hint an object should override the ``_eval_expand_basic`` method.
Objects may also define their own expand methods, which are not run by
default. See the API section below.
If ``deep`` is set to ``True`` (the default), things like arguments of
functions are recursively expanded. Use ``deep=False`` to only expand on
the top level.
If the ``force`` hint is used, assumptions about variables will be ignored
in making the expansion.
Hints
=====
These hints are run by default
mul
---
Distributes multiplication over addition:
>>> from sympy import cos, exp, sin
>>> from sympy.abc import x, y, z
>>> (y*(x + z)).expand(mul=True)
x*y + y*z
multinomial
-----------
Expand (x + y + ...)**n where n is a positive integer.
>>> ((x + y + z)**2).expand(multinomial=True)
x**2 + 2*x*y + 2*x*z + y**2 + 2*y*z + z**2
power_exp
---------
Expand addition in exponents into multiplied bases.
>>> exp(x + y).expand(power_exp=True)
exp(x)*exp(y)
>>> (2**(x + y)).expand(power_exp=True)
2**x*2**y
power_base
----------
Split powers of multiplied bases.
This only happens by default if assumptions allow, or if the
``force`` meta-hint is used:
>>> ((x*y)**z).expand(power_base=True)
(x*y)**z
>>> ((x*y)**z).expand(power_base=True, force=True)
x**z*y**z
>>> ((2*y)**z).expand(power_base=True)
2**z*y**z
Note that in some cases where this expansion always holds, SymPy performs
it automatically:
>>> (x*y)**2
x**2*y**2
log
---
Pull out power of an argument as a coefficient and split logs products
into sums of logs.
Note that these only work if the arguments of the log function have the
proper assumptions--the arguments must be positive and the exponents must
be real--or else the ``force`` hint must be True:
>>> from sympy import log, symbols
>>> log(x**2*y).expand(log=True)
log(x**2*y)
>>> log(x**2*y).expand(log=True, force=True)
2*log(x) + log(y)
>>> x, y = symbols('x,y', positive=True)
>>> log(x**2*y).expand(log=True)
2*log(x) + log(y)
basic
-----
This hint is intended primarily as a way for custom subclasses to enable
expansion by default.
These hints are not run by default:
complex
-------
Split an expression into real and imaginary parts.
>>> x, y = symbols('x,y')
>>> (x + y).expand(complex=True)
re(x) + re(y) + I*im(x) + I*im(y)
>>> cos(x).expand(complex=True)
-I*sin(re(x))*sinh(im(x)) + cos(re(x))*cosh(im(x))
Note that this is just a wrapper around ``as_real_imag()``. Most objects
that wish to redefine ``_eval_expand_complex()`` should consider
redefining ``as_real_imag()`` instead.
func
----
Expand other functions.
>>> from sympy import gamma
>>> gamma(x + 1).expand(func=True)
x*gamma(x)
trig
----
Do trigonometric expansions.
>>> cos(x + y).expand(trig=True)
-sin(x)*sin(y) + cos(x)*cos(y)
>>> sin(2*x).expand(trig=True)
2*sin(x)*cos(x)
Note that the forms of ``sin(n*x)`` and ``cos(n*x)`` in terms of ``sin(x)``
and ``cos(x)`` are not unique, due to the identity `\sin^2(x) + \cos^2(x)
= 1`. The current implementation uses the form obtained from Chebyshev
polynomials, but this may change. See `this MathWorld article
<https://mathworld.wolfram.com/Multiple-AngleFormulas.html>`_ for more
information.
Notes
=====
- You can shut off unwanted methods::
>>> (exp(x + y)*(x + y)).expand()
x*exp(x)*exp(y) + y*exp(x)*exp(y)
>>> (exp(x + y)*(x + y)).expand(power_exp=False)
x*exp(x + y) + y*exp(x + y)
>>> (exp(x + y)*(x + y)).expand(mul=False)
(x + y)*exp(x)*exp(y)
- Use deep=False to only expand on the top level::
>>> exp(x + exp(x + y)).expand()
exp(x)*exp(exp(x)*exp(y))
>>> exp(x + exp(x + y)).expand(deep=False)
exp(x)*exp(exp(x + y))
- Hints are applied in an arbitrary, but consistent order (in the current
implementation, they are applied in alphabetical order, except
multinomial comes before mul, but this may change). Because of this,
some hints may prevent expansion by other hints if they are applied
first. For example, ``mul`` may distribute multiplications and prevent
``log`` and ``power_base`` from expanding them. Also, if ``mul`` is
applied before ``multinomial`, the expression might not be fully
distributed. The solution is to use the various ``expand_hint`` helper
functions or to use ``hint=False`` to this function to finely control
which hints are applied. Here are some examples::
>>> from sympy import expand, expand_mul, expand_power_base
>>> x, y, z = symbols('x,y,z', positive=True)
>>> expand(log(x*(y + z)))
log(x) + log(y + z)
Here, we see that ``log`` was applied before ``mul``. To get the mul
expanded form, either of the following will work::
>>> expand_mul(log(x*(y + z)))
log(x*y + x*z)
>>> expand(log(x*(y + z)), log=False)
log(x*y + x*z)
A similar thing can happen with the ``power_base`` hint::
>>> expand((x*(y + z))**x)
(x*y + x*z)**x
To get the ``power_base`` expanded form, either of the following will
work::
>>> expand((x*(y + z))**x, mul=False)
x**x*(y + z)**x
>>> expand_power_base((x*(y + z))**x)
x**x*(y + z)**x
>>> expand((x + y)*y/x)
y + y**2/x
The parts of a rational expression can be targeted::
>>> expand((x + y)*y/x/(x + 1), frac=True)
(x*y + y**2)/(x**2 + x)
>>> expand((x + y)*y/x/(x + 1), numer=True)
(x*y + y**2)/(x*(x + 1))
>>> expand((x + y)*y/x/(x + 1), denom=True)
y*(x + y)/(x**2 + x)
- The ``modulus`` meta-hint can be used to reduce the coefficients of an
expression post-expansion::
>>> expand((3*x + 1)**2)
9*x**2 + 6*x + 1
>>> expand((3*x + 1)**2, modulus=5)
4*x**2 + x + 1
- Either ``expand()`` the function or ``.expand()`` the method can be
used. Both are equivalent::
>>> expand((x + 1)**2)
x**2 + 2*x + 1
>>> ((x + 1)**2).expand()
x**2 + 2*x + 1
API
===
Objects can define their own expand hints by defining
``_eval_expand_hint()``. The function should take the form::
def _eval_expand_hint(self, **hints):
# Only apply the method to the top-level expression
...
See also the example below. Objects should define ``_eval_expand_hint()``
methods only if ``hint`` applies to that specific object. The generic
``_eval_expand_hint()`` method defined in Expr will handle the no-op case.
Each hint should be responsible for expanding that hint only.
Furthermore, the expansion should be applied to the top-level expression
only. ``expand()`` takes care of the recursion that happens when
``deep=True``.
You should only call ``_eval_expand_hint()`` methods directly if you are
100% sure that the object has the method, as otherwise you are liable to
get unexpected ``AttributeError``s. Note, again, that you do not need to
recursively apply the hint to args of your object: this is handled
automatically by ``expand()``. ``_eval_expand_hint()`` should
generally not be used at all outside of an ``_eval_expand_hint()`` method.
If you want to apply a specific expansion from within another method, use
the public ``expand()`` function, method, or ``expand_hint()`` functions.
In order for expand to work, objects must be rebuildable by their args,
i.e., ``obj.func(*obj.args) == obj`` must hold.
Expand methods are passed ``**hints`` so that expand hints may use
'metahints'--hints that control how different expand methods are applied.
For example, the ``force=True`` hint described above that causes
``expand(log=True)`` to ignore assumptions is such a metahint. The
``deep`` meta-hint is handled exclusively by ``expand()`` and is not
passed to ``_eval_expand_hint()`` methods.
Note that expansion hints should generally be methods that perform some
kind of 'expansion'. For hints that simply rewrite an expression, use the
.rewrite() API.
Examples
========
>>> from sympy import Expr, sympify
>>> class MyClass(Expr):
... def __new__(cls, *args):
... args = sympify(args)
... return Expr.__new__(cls, *args)
...
... def _eval_expand_double(self, *, force=False, **hints):
... '''
... Doubles the args of MyClass.
...
... If there more than four args, doubling is not performed,
... unless force=True is also used (False by default).
... '''
... if not force and len(self.args) > 4:
... return self
... return self.func(*(self.args + self.args))
...
>>> a = MyClass(1, 2, MyClass(3, 4))
>>> a
MyClass(1, 2, MyClass(3, 4))
>>> a.expand(double=True)
MyClass(1, 2, MyClass(3, 4, 3, 4), 1, 2, MyClass(3, 4, 3, 4))
>>> a.expand(double=True, deep=False)
MyClass(1, 2, MyClass(3, 4), 1, 2, MyClass(3, 4))
>>> b = MyClass(1, 2, 3, 4, 5)
>>> b.expand(double=True)
MyClass(1, 2, 3, 4, 5)
>>> b.expand(double=True, force=True)
MyClass(1, 2, 3, 4, 5, 1, 2, 3, 4, 5)
See Also
========
expand_log, expand_mul, expand_multinomial, expand_complex, expand_trig,
expand_power_base, expand_power_exp, expand_func, sympy.simplify.hyperexpand.hyperexpand
"""
# don't modify this; modify the Expr.expand method
hints['power_base'] = power_base
hints['power_exp'] = power_exp
hints['mul'] = mul
hints['log'] = log
hints['multinomial'] = multinomial
hints['basic'] = basic
return sympify(e).expand(deep=deep, modulus=modulus, **hints)
# This is a special application of two hints
def _mexpand(expr, recursive=False):
# expand multinomials and then expand products; this may not always
# be sufficient to give a fully expanded expression (see
# test_issue_8247_8354 in test_arit)
if expr is None:
return
was = None
while was != expr:
was, expr = expr, expand_mul(expand_multinomial(expr))
if not recursive:
break
return expr
# These are simple wrappers around single hints.
def expand_mul(expr, deep=True):
"""
Wrapper around expand that only uses the mul hint. See the expand
docstring for more information.
Examples
========
>>> from sympy import symbols, expand_mul, exp, log
>>> x, y = symbols('x,y', positive=True)
>>> expand_mul(exp(x+y)*(x+y)*log(x*y**2))
x*exp(x + y)*log(x*y**2) + y*exp(x + y)*log(x*y**2)
"""
return sympify(expr).expand(deep=deep, mul=True, power_exp=False,
power_base=False, basic=False, multinomial=False, log=False)
def expand_multinomial(expr, deep=True):
"""
Wrapper around expand that only uses the multinomial hint. See the expand
docstring for more information.
Examples
========
>>> from sympy import symbols, expand_multinomial, exp
>>> x, y = symbols('x y', positive=True)
>>> expand_multinomial((x + exp(x + 1))**2)
x**2 + 2*x*exp(x + 1) + exp(2*x + 2)
"""
return sympify(expr).expand(deep=deep, mul=False, power_exp=False,
power_base=False, basic=False, multinomial=True, log=False)
def expand_log(expr, deep=True, force=False, factor=False):
"""
Wrapper around expand that only uses the log hint. See the expand
docstring for more information.
Examples
========
>>> from sympy import symbols, expand_log, exp, log
>>> x, y = symbols('x,y', positive=True)
>>> expand_log(exp(x+y)*(x+y)*log(x*y**2))
(x + y)*(log(x) + 2*log(y))*exp(x + y)
"""
from sympy.functions.elementary.exponential import log
from sympy.simplify.radsimp import fraction
if factor is False:
def _handleMul(x):
# look for the simple case of expanded log(b**a)/log(b) -> a in args
n, d = fraction(x)
n = [i for i in n.atoms(log) if i.args[0].is_Integer]
d = [i for i in d.atoms(log) if i.args[0].is_Integer]
if len(n) == 1 and len(d) == 1:
n = n[0]
d = d[0]
from sympy import multiplicity
m = multiplicity(d.args[0], n.args[0])
if m:
r = m + log(n.args[0]//d.args[0]**m)/d
x = x.subs(n, d*r)
x1 = expand_mul(expand_log(x, deep=deep, force=force, factor=True))
if x1.count(log) <= x.count(log):
return x1
return x
expr = expr.replace(
lambda x: x.is_Mul and all(any(isinstance(i, log) and i.args[0].is_Rational
for i in Mul.make_args(j)) for j in x.as_numer_denom()),
_handleMul)
return sympify(expr).expand(deep=deep, log=True, mul=False,
power_exp=False, power_base=False, multinomial=False,
basic=False, force=force, factor=factor)
def expand_func(expr, deep=True):
"""
Wrapper around expand that only uses the func hint. See the expand
docstring for more information.
Examples
========
>>> from sympy import expand_func, gamma
>>> from sympy.abc import x
>>> expand_func(gamma(x + 2))
x*(x + 1)*gamma(x)
"""
return sympify(expr).expand(deep=deep, func=True, basic=False,
log=False, mul=False, power_exp=False, power_base=False, multinomial=False)
def expand_trig(expr, deep=True):
"""
Wrapper around expand that only uses the trig hint. See the expand
docstring for more information.
Examples
========
>>> from sympy import expand_trig, sin
>>> from sympy.abc import x, y
>>> expand_trig(sin(x+y)*(x+y))
(x + y)*(sin(x)*cos(y) + sin(y)*cos(x))
"""
return sympify(expr).expand(deep=deep, trig=True, basic=False,
log=False, mul=False, power_exp=False, power_base=False, multinomial=False)
def expand_complex(expr, deep=True):
"""
Wrapper around expand that only uses the complex hint. See the expand
docstring for more information.
Examples
========
>>> from sympy import expand_complex, exp, sqrt, I
>>> from sympy.abc import z
>>> expand_complex(exp(z))
I*exp(re(z))*sin(im(z)) + exp(re(z))*cos(im(z))
>>> expand_complex(sqrt(I))
sqrt(2)/2 + sqrt(2)*I/2
See Also
========
sympy.core.expr.Expr.as_real_imag
"""
return sympify(expr).expand(deep=deep, complex=True, basic=False,
log=False, mul=False, power_exp=False, power_base=False, multinomial=False)
def expand_power_base(expr, deep=True, force=False):
"""
Wrapper around expand that only uses the power_base hint.
A wrapper to expand(power_base=True) which separates a power with a base
that is a Mul into a product of powers, without performing any other
expansions, provided that assumptions about the power's base and exponent
allow.
deep=False (default is True) will only apply to the top-level expression.
force=True (default is False) will cause the expansion to ignore
assumptions about the base and exponent. When False, the expansion will
only happen if the base is non-negative or the exponent is an integer.
>>> from sympy.abc import x, y, z
>>> from sympy import expand_power_base, sin, cos, exp, Symbol
>>> (x*y)**2
x**2*y**2
>>> (2*x)**y
(2*x)**y
>>> expand_power_base(_)
2**y*x**y
>>> expand_power_base((x*y)**z)
(x*y)**z
>>> expand_power_base((x*y)**z, force=True)
x**z*y**z
>>> expand_power_base(sin((x*y)**z), deep=False)
sin((x*y)**z)
>>> expand_power_base(sin((x*y)**z), force=True)
sin(x**z*y**z)
>>> expand_power_base((2*sin(x))**y + (2*cos(x))**y)
2**y*sin(x)**y + 2**y*cos(x)**y
>>> expand_power_base((2*exp(y))**x)
2**x*exp(y)**x
>>> expand_power_base((2*cos(x))**y)
2**y*cos(x)**y
Notice that sums are left untouched. If this is not the desired behavior,
apply full ``expand()`` to the expression:
>>> expand_power_base(((x+y)*z)**2)
z**2*(x + y)**2
>>> (((x+y)*z)**2).expand()
x**2*z**2 + 2*x*y*z**2 + y**2*z**2
>>> expand_power_base((2*y)**(1+z))
2**(z + 1)*y**(z + 1)
>>> ((2*y)**(1+z)).expand()
2*2**z*y**(z + 1)
The power that is unexpanded can be expanded safely when
``y != 0``, otherwise different values might be obtained for the expression:
>>> prev = _
If we indicate that ``y`` is positive but then replace it with
a value of 0 after expansion, the expression becomes 0:
>>> p = Symbol('p', positive=True)
>>> prev.subs(y, p).expand().subs(p, 0)
0
But if ``z = -1`` the expression would not be zero:
>>> prev.subs(y, 0).subs(z, -1)
1
See Also
========
expand
"""
return sympify(expr).expand(deep=deep, log=False, mul=False,
power_exp=False, power_base=True, multinomial=False,
basic=False, force=force)
def expand_power_exp(expr, deep=True):
"""
Wrapper around expand that only uses the power_exp hint.
See the expand docstring for more information.
Examples
========
>>> from sympy import expand_power_exp, Symbol
>>> from sympy.abc import x, y
>>> expand_power_exp(3**(y + 2))
9*3**y
>>> expand_power_exp(x**(y + 2))
x**(y + 2)
If ``x = 0`` the value of the expression depends on the
value of ``y``; if the expression were expanded the result
would be 0. So expansion is only done if ``x != 0``:
>>> expand_power_exp(Symbol('x', zero=False)**(y + 2))
x**2*x**y
"""
return sympify(expr).expand(deep=deep, complex=False, basic=False,
log=False, mul=False, power_exp=True, power_base=False, multinomial=False)
def count_ops(expr, visual=False):
"""
Return a representation (integer or expression) of the operations in expr.
Parameters
==========
expr : Expr
If expr is an iterable, the sum of the op counts of the
items will be returned.
visual : bool, optional
If ``False`` (default) then the sum of the coefficients of the
visual expression will be returned.
If ``True`` then the number of each type of operation is shown
with the core class types (or their virtual equivalent) multiplied by the
number of times they occur.
Examples
========
>>> from sympy.abc import a, b, x, y
>>> from sympy import sin, count_ops
Although there is not a SUB object, minus signs are interpreted as
either negations or subtractions:
>>> (x - y).count_ops(visual=True)
SUB
>>> (-x).count_ops(visual=True)
NEG
Here, there are two Adds and a Pow:
>>> (1 + a + b**2).count_ops(visual=True)
2*ADD + POW
In the following, an Add, Mul, Pow and two functions:
>>> (sin(x)*x + sin(x)**2).count_ops(visual=True)
ADD + MUL + POW + 2*SIN
for a total of 5:
>>> (sin(x)*x + sin(x)**2).count_ops(visual=False)
5
Note that "what you type" is not always what you get. The expression
1/x/y is translated by sympy into 1/(x*y) so it gives a DIV and MUL rather
than two DIVs:
>>> (1/x/y).count_ops(visual=True)
DIV + MUL
The visual option can be used to demonstrate the difference in
operations for expressions in different forms. Here, the Horner
representation is compared with the expanded form of a polynomial:
>>> eq=x*(1 + x*(2 + x*(3 + x)))
>>> count_ops(eq.expand(), visual=True) - count_ops(eq, visual=True)
-MUL + 3*POW
The count_ops function also handles iterables:
>>> count_ops([x, sin(x), None, True, x + 2], visual=False)
2
>>> count_ops([x, sin(x), None, True, x + 2], visual=True)
ADD + SIN
>>> count_ops({x: sin(x), x + 2: y + 1}, visual=True)
2*ADD + SIN
"""
from .relational import Relational
from sympy.concrete.summations import Sum
from sympy.integrals.integrals import Integral
from sympy.logic.boolalg import BooleanFunction
from sympy.simplify.radsimp import fraction
expr = sympify(expr)
if isinstance(expr, Expr) and not expr.is_Relational:
ops = []
args = [expr]
NEG = Symbol('NEG')
DIV = Symbol('DIV')
SUB = Symbol('SUB')
ADD = Symbol('ADD')
EXP = Symbol('EXP')
while args:
a = args.pop()
# if the following fails because the object is
# not Basic type, then the object should be fixed
# since it is the intention that all args of Basic
# should themselves be Basic
if a.is_Rational:
#-1/3 = NEG + DIV
if a is not S.One:
if a.p < 0:
ops.append(NEG)
if a.q != 1:
ops.append(DIV)
continue
elif a.is_Mul or a.is_MatMul:
if _coeff_isneg(a):
ops.append(NEG)
if a.args[0] is S.NegativeOne:
a = a.as_two_terms()[1]
else:
a = -a
n, d = fraction(a)
if n.is_Integer:
ops.append(DIV)
if n < 0:
ops.append(NEG)
args.append(d)
continue # won't be -Mul but could be Add
elif d is not S.One:
if not d.is_Integer:
args.append(d)
ops.append(DIV)
args.append(n)
continue # could be -Mul
elif a.is_Add or a.is_MatAdd:
aargs = list(a.args)
negs = 0
for i, ai in enumerate(aargs):
if _coeff_isneg(ai):
negs += 1
args.append(-ai)
if i > 0:
ops.append(SUB)
else:
args.append(ai)
if i > 0:
ops.append(ADD)
if negs == len(aargs): # -x - y = NEG + SUB
ops.append(NEG)
elif _coeff_isneg(aargs[0]): # -x + y = SUB, but already recorded ADD
ops.append(SUB - ADD)
continue
if a.is_Pow and a.exp is S.NegativeOne:
ops.append(DIV)
args.append(a.base) # won't be -Mul but could be Add
continue
if a == S.Exp1:
ops.append(EXP)
continue
if a.is_Pow and a.base == S.Exp1:
ops.append(EXP)
args.append(a.exp)
continue
if a.is_Mul or isinstance(a, LatticeOp):
o = Symbol(a.func.__name__.upper())
# count the args
ops.append(o*(len(a.args) - 1))
elif a.args and (
a.is_Pow or a.is_Function or isinstance(a, (Derivative, Integral, Sum))):
# if it's not in the list above we don't
# consider a.func something to count, e.g.
# Tuple, MatrixSymbol, etc...
if isinstance(a.func, UndefinedFunction):
o = Symbol("FUNC_" + a.func.__name__.upper())
else:
o = Symbol(a.func.__name__.upper())
ops.append(o)
if not a.is_Symbol:
args.extend(a.args)
elif isinstance(expr, Dict):
ops = [count_ops(k, visual=visual) +
count_ops(v, visual=visual) for k, v in expr.items()]
elif iterable(expr):
ops = [count_ops(i, visual=visual) for i in expr]
elif isinstance(expr, (Relational, BooleanFunction)):
ops = []
for arg in expr.args:
ops.append(count_ops(arg, visual=True))
o = Symbol(func_name(expr, short=True).upper())
ops.append(o)
elif not isinstance(expr, Basic):
ops = []
else: # it's Basic not isinstance(expr, Expr):
if not isinstance(expr, Basic):
raise TypeError("Invalid type of expr")
else:
ops = []
args = [expr]
while args:
a = args.pop()
if a.args:
o = Symbol(type(a).__name__.upper())
if a.is_Boolean:
ops.append(o*(len(a.args)-1))
else:
ops.append(o)
args.extend(a.args)
if not ops:
if visual:
return S.Zero
return 0
ops = Add(*ops)
if visual:
return ops
if ops.is_Number:
return int(ops)
return sum(int((a.args or [1])[0]) for a in Add.make_args(ops))
def nfloat(expr, n=15, exponent=False, dkeys=False):
"""Make all Rationals in expr Floats except those in exponents
(unless the exponents flag is set to True) and those in undefined
functions. When processing dictionaries, do not modify the keys
unless ``dkeys=True``.
Examples
========
>>> from sympy import nfloat, cos, pi, sqrt
>>> from sympy.abc import x, y
>>> nfloat(x**4 + x/2 + cos(pi/3) + 1 + sqrt(y))
x**4 + 0.5*x + sqrt(y) + 1.5
>>> nfloat(x**4 + sqrt(y), exponent=True)
x**4.0 + y**0.5
Container types are not modified:
>>> type(nfloat((1, 2))) is tuple
True
"""
from sympy.matrices.matrixbase import MatrixBase
kw = {"n": n, "exponent": exponent, "dkeys": dkeys}
if isinstance(expr, MatrixBase):
return expr.applyfunc(lambda e: nfloat(e, **kw))
# handling of iterable containers
if iterable(expr, exclude=str):
if isinstance(expr, (dict, Dict)):
if dkeys:
args = [tuple((nfloat(i, **kw) for i in a))
for a in expr.items()]
else:
args = [(k, nfloat(v, **kw)) for k, v in expr.items()]
if isinstance(expr, dict):
return type(expr)(args)
else:
return expr.func(*args)
elif isinstance(expr, Basic):
return expr.func(*[nfloat(a, **kw) for a in expr.args])
return type(expr)([nfloat(a, **kw) for a in expr])
rv = sympify(expr)
if rv.is_Number:
return Float(rv, n)
elif rv.is_number:
# evalf doesn't always set the precision
rv = rv.n(n)
if rv.is_Number:
rv = Float(rv.n(n), n)
else:
pass # pure_complex(rv) is likely True
return rv
elif rv.is_Atom:
return rv
elif rv.is_Relational:
args_nfloat = (nfloat(arg, **kw) for arg in rv.args)
return rv.func(*args_nfloat)
# watch out for RootOf instances that don't like to have
# their exponents replaced with Dummies and also sometimes have
# problems with evaluating at low precision (issue 6393)
from sympy.polys.rootoftools import RootOf
rv = rv.xreplace({ro: ro.n(n) for ro in rv.atoms(RootOf)})
from .power import Pow
if not exponent:
reps = [(p, Pow(p.base, Dummy())) for p in rv.atoms(Pow)]
rv = rv.xreplace(dict(reps))
rv = rv.n(n)
if not exponent:
rv = rv.xreplace({d.exp: p.exp for p, d in reps})
else:
# Pow._eval_evalf special cases Integer exponents so if
# exponent is suppose to be handled we have to do so here
rv = rv.xreplace(Transform(
lambda x: Pow(x.base, Float(x.exp, n)),
lambda x: x.is_Pow and x.exp.is_Integer))
return rv.xreplace(Transform(
lambda x: x.func(*nfloat(x.args, n, exponent)),
lambda x: isinstance(x, Function) and not isinstance(x, AppliedUndef)))
from .symbol import Dummy, Symbol
PK ]ZZZ�.ߓ�7 �7 sympy/core/intfunc.py"""
The routines here were removed from numbers.py, power.py,
digits.py and factor_.py so they could be imported into core
without raising circular import errors.
Although the name 'intfunc' was chosen to represent functions that
work with integers, it can also be thought of as containing
internal/core functions that are needed by the classes of the core.
"""
import math
import sys
from functools import lru_cache
from .sympify import sympify
from .singleton import S
from sympy.external.gmpy import (gcd as number_gcd, lcm as number_lcm, sqrt,
iroot, bit_scan1, gcdext)
from sympy.utilities.misc import as_int, filldedent
def num_digits(n, base=10):
"""Return the number of digits needed to express n in give base.
Examples
========
>>> from sympy.core.intfunc import num_digits
>>> num_digits(10)
2
>>> num_digits(10, 2) # 1010 -> 4 digits
4
>>> num_digits(-100, 16) # -64 -> 2 digits
2
Parameters
==========
n: integer
The number whose digits are counted.
b: integer
The base in which digits are computed.
See Also
========
sympy.ntheory.digits.digits, sympy.ntheory.digits.count_digits
"""
if base < 0:
raise ValueError('base must be int greater than 1')
if not n:
return 1
e, t = integer_log(abs(n), base)
return 1 + e
def integer_log(n, b):
r"""
Returns ``(e, bool)`` where e is the largest nonnegative integer
such that :math:`|n| \geq |b^e|` and ``bool`` is True if $n = b^e$.
Examples
========
>>> from sympy import integer_log
>>> integer_log(125, 5)
(3, True)
>>> integer_log(17, 9)
(1, False)
If the base is positive and the number negative the
return value will always be the same except for 2:
>>> integer_log(-4, 2)
(2, False)
>>> integer_log(-16, 4)
(0, False)
When the base is negative, the returned value
will only be True if the parity of the exponent is
correct for the sign of the base:
>>> integer_log(4, -2)
(2, True)
>>> integer_log(8, -2)
(3, False)
>>> integer_log(-8, -2)
(3, True)
>>> integer_log(-4, -2)
(2, False)
See Also
========
integer_nthroot
sympy.ntheory.primetest.is_square
sympy.ntheory.factor_.multiplicity
sympy.ntheory.factor_.perfect_power
"""
n = as_int(n)
b = as_int(b)
if b < 0:
e, t = integer_log(abs(n), -b)
# (-2)**3 == -8
# (-2)**2 = 4
t = t and e % 2 == (n < 0)
return e, t
if b <= 1:
raise ValueError('base must be 2 or more')
if n < 0:
if b != 2:
return 0, False
e, t = integer_log(-n, b)
return e, False
if n == 0:
raise ValueError('n cannot be 0')
if n < b:
return 0, n == 1
if b == 2:
e = n.bit_length() - 1
return e, trailing(n) == e
t = trailing(b)
if 2**t == b:
e = int(n.bit_length() - 1)//t
n_ = 1 << (t*e)
return e, n_ == n
d = math.floor(math.log10(n) / math.log10(b))
n_ = b ** d
while n_ <= n: # this will iterate 0, 1 or 2 times
d += 1
n_ *= b
return d - (n_ > n), (n_ == n or n_//b == n)
def trailing(n):
"""Count the number of trailing zero digits in the binary
representation of n, i.e. determine the largest power of 2
that divides n.
Examples
========
>>> from sympy import trailing
>>> trailing(128)
7
>>> trailing(63)
0
See Also
========
sympy.ntheory.factor_.multiplicity
"""
if not n:
return 0
return bit_scan1(int(n))
@lru_cache(1024)
def igcd(*args):
"""Computes nonnegative integer greatest common divisor.
Explanation
===========
The algorithm is based on the well known Euclid's algorithm [1]_. To
improve speed, ``igcd()`` has its own caching mechanism.
If you do not need the cache mechanism, using ``sympy.external.gmpy.gcd``.
Examples
========
>>> from sympy import igcd
>>> igcd(2, 4)
2
>>> igcd(5, 10, 15)
5
References
==========
.. [1] https://en.wikipedia.org/wiki/Euclidean_algorithm
"""
if len(args) < 2:
raise TypeError("igcd() takes at least 2 arguments (%s given)" % len(args))
return int(number_gcd(*map(as_int, args)))
igcd2 = math.gcd
def igcd_lehmer(a, b):
r"""Computes greatest common divisor of two integers.
Explanation
===========
Euclid's algorithm for the computation of the greatest
common divisor ``gcd(a, b)`` of two (positive) integers
$a$ and $b$ is based on the division identity
$$ a = q \times b + r$$,
where the quotient $q$ and the remainder $r$ are integers
and $0 \le r < b$. Then each common divisor of $a$ and $b$
divides $r$, and it follows that ``gcd(a, b) == gcd(b, r)``.
The algorithm works by constructing the sequence
r0, r1, r2, ..., where r0 = a, r1 = b, and each rn
is the remainder from the division of the two preceding
elements.
In Python, ``q = a // b`` and ``r = a % b`` are obtained by the
floor division and the remainder operations, respectively.
These are the most expensive arithmetic operations, especially
for large a and b.
Lehmer's algorithm [1]_ is based on the observation that the quotients
``qn = r(n-1) // rn`` are in general small integers even
when a and b are very large. Hence the quotients can be
usually determined from a relatively small number of most
significant bits.
The efficiency of the algorithm is further enhanced by not
computing each long remainder in Euclid's sequence. The remainders
are linear combinations of a and b with integer coefficients
derived from the quotients. The coefficients can be computed
as far as the quotients can be determined from the chosen
most significant parts of a and b. Only then a new pair of
consecutive remainders is computed and the algorithm starts
anew with this pair.
References
==========
.. [1] https://en.wikipedia.org/wiki/Lehmer%27s_GCD_algorithm
"""
a, b = abs(as_int(a)), abs(as_int(b))
if a < b:
a, b = b, a
# The algorithm works by using one or two digit division
# whenever possible. The outer loop will replace the
# pair (a, b) with a pair of shorter consecutive elements
# of the Euclidean gcd sequence until a and b
# fit into two Python (long) int digits.
nbits = 2 * sys.int_info.bits_per_digit
while a.bit_length() > nbits and b != 0:
# Quotients are mostly small integers that can
# be determined from most significant bits.
n = a.bit_length() - nbits
x, y = int(a >> n), int(b >> n) # most significant bits
# Elements of the Euclidean gcd sequence are linear
# combinations of a and b with integer coefficients.
# Compute the coefficients of consecutive pairs
# a' = A*a + B*b, b' = C*a + D*b
# using small integer arithmetic as far as possible.
A, B, C, D = 1, 0, 0, 1 # initial values
while True:
# The coefficients alternate in sign while looping.
# The inner loop combines two steps to keep track
# of the signs.
# At this point we have
# A > 0, B <= 0, C <= 0, D > 0,
# x' = x + B <= x < x" = x + A,
# y' = y + C <= y < y" = y + D,
# and
# x'*N <= a' < x"*N, y'*N <= b' < y"*N,
# where N = 2**n.
# Now, if y' > 0, and x"//y' and x'//y" agree,
# then their common value is equal to q = a'//b'.
# In addition,
# x'%y" = x' - q*y" < x" - q*y' = x"%y',
# and
# (x'%y")*N < a'%b' < (x"%y')*N.
# On the other hand, we also have x//y == q,
# and therefore
# x'%y" = x + B - q*(y + D) = x%y + B',
# x"%y' = x + A - q*(y + C) = x%y + A',
# where
# B' = B - q*D < 0, A' = A - q*C > 0.
if y + C <= 0:
break
q = (x + A) // (y + C)
# Now x'//y" <= q, and equality holds if
# x' - q*y" = (x - q*y) + (B - q*D) >= 0.
# This is a minor optimization to avoid division.
x_qy, B_qD = x - q * y, B - q * D
if x_qy + B_qD < 0:
break
# Next step in the Euclidean sequence.
x, y = y, x_qy
A, B, C, D = C, D, A - q * C, B_qD
# At this point the signs of the coefficients
# change and their roles are interchanged.
# A <= 0, B > 0, C > 0, D < 0,
# x' = x + A <= x < x" = x + B,
# y' = y + D < y < y" = y + C.
if y + D <= 0:
break
q = (x + B) // (y + D)
x_qy, A_qC = x - q * y, A - q * C
if x_qy + A_qC < 0:
break
x, y = y, x_qy
A, B, C, D = C, D, A_qC, B - q * D
# Now the conditions on top of the loop
# are again satisfied.
# A > 0, B < 0, C < 0, D > 0.
if B == 0:
# This can only happen when y == 0 in the beginning
# and the inner loop does nothing.
# Long division is forced.
a, b = b, a % b
continue
# Compute new long arguments using the coefficients.
a, b = A * a + B * b, C * a + D * b
# Small divisors. Finish with the standard algorithm.
while b:
a, b = b, a % b
return a
def ilcm(*args):
"""Computes integer least common multiple.
Examples
========
>>> from sympy import ilcm
>>> ilcm(5, 10)
10
>>> ilcm(7, 3)
21
>>> ilcm(5, 10, 15)
30
"""
if len(args) < 2:
raise TypeError("ilcm() takes at least 2 arguments (%s given)" % len(args))
return int(number_lcm(*map(as_int, args)))
def igcdex(a, b):
"""Returns x, y, g such that g = x*a + y*b = gcd(a, b).
Examples
========
>>> from sympy.core.intfunc import igcdex
>>> igcdex(2, 3)
(-1, 1, 1)
>>> igcdex(10, 12)
(-1, 1, 2)
>>> x, y, g = igcdex(100, 2004)
>>> x, y, g
(-20, 1, 4)
>>> x*100 + y*2004
4
"""
if (not a) and (not b):
return (0, 1, 0)
g, x, y = gcdext(int(a), int(b))
return x, y, g
def mod_inverse(a, m):
r"""
Return the number $c$ such that, $a \times c = 1 \pmod{m}$
where $c$ has the same sign as $m$. If no such value exists,
a ValueError is raised.
Examples
========
>>> from sympy import mod_inverse, S
Suppose we wish to find multiplicative inverse $x$ of
3 modulo 11. This is the same as finding $x$ such
that $3x = 1 \pmod{11}$. One value of x that satisfies
this congruence is 4. Because $3 \times 4 = 12$ and $12 = 1 \pmod{11}$.
This is the value returned by ``mod_inverse``:
>>> mod_inverse(3, 11)
4
>>> mod_inverse(-3, 11)
7
When there is a common factor between the numerators of
`a` and `m` the inverse does not exist:
>>> mod_inverse(2, 4)
Traceback (most recent call last):
...
ValueError: inverse of 2 mod 4 does not exist
>>> mod_inverse(S(2)/7, S(5)/2)
7/2
References
==========
.. [1] https://en.wikipedia.org/wiki/Modular_multiplicative_inverse
.. [2] https://en.wikipedia.org/wiki/Extended_Euclidean_algorithm
"""
c = None
try:
a, m = as_int(a), as_int(m)
if m != 1 and m != -1:
x, _, g = igcdex(a, m)
if g == 1:
c = x % m
except ValueError:
a, m = sympify(a), sympify(m)
if not (a.is_number and m.is_number):
raise TypeError(
filldedent(
"""
Expected numbers for arguments; symbolic `mod_inverse`
is not implemented
but symbolic expressions can be handled with the
similar function,
sympy.polys.polytools.invert"""
)
)
big = m > 1
if big not in (S.true, S.false):
raise ValueError("m > 1 did not evaluate; try to simplify %s" % m)
elif big:
c = 1 / a
if c is None:
raise ValueError("inverse of %s (mod %s) does not exist" % (a, m))
return c
def isqrt(n):
r""" Return the largest integer less than or equal to `\sqrt{n}`.
Parameters
==========
n : non-negative integer
Returns
=======
int : `\left\lfloor\sqrt{n}\right\rfloor`
Raises
======
ValueError
If n is negative.
TypeError
If n is of a type that cannot be compared to ``int``.
Therefore, a TypeError is raised for ``str``, but not for ``float``.
Examples
========
>>> from sympy.core.intfunc import isqrt
>>> isqrt(0)
0
>>> isqrt(9)
3
>>> isqrt(10)
3
>>> isqrt("30")
Traceback (most recent call last):
...
TypeError: '<' not supported between instances of 'str' and 'int'
>>> from sympy.core.numbers import Rational
>>> isqrt(Rational(-1, 2))
Traceback (most recent call last):
...
ValueError: n must be nonnegative
"""
if n < 0:
raise ValueError("n must be nonnegative")
return int(sqrt(int(n)))
def integer_nthroot(y, n):
"""
Return a tuple containing x = floor(y**(1/n))
and a boolean indicating whether the result is exact (that is,
whether x**n == y).
Examples
========
>>> from sympy import integer_nthroot
>>> integer_nthroot(16, 2)
(4, True)
>>> integer_nthroot(26, 2)
(5, False)
To simply determine if a number is a perfect square, the is_square
function should be used:
>>> from sympy.ntheory.primetest import is_square
>>> is_square(26)
False
See Also
========
sympy.ntheory.primetest.is_square
integer_log
"""
x, b = iroot(as_int(y), as_int(n))
return int(x), b
PK ]ZZZgwj- - sympy/core/kind.py"""
Module to efficiently partition SymPy objects.
This system is introduced because class of SymPy object does not always
represent the mathematical classification of the entity. For example,
``Integral(1, x)`` and ``Integral(Matrix([1,2]), x)`` are both instance
of ``Integral`` class. However the former is number and the latter is
matrix.
One way to resolve this is defining subclass for each mathematical type,
such as ``MatAdd`` for the addition between matrices. Basic algebraic
operation such as addition or multiplication take this approach, but
defining every class for every mathematical object is not scalable.
Therefore, we define the "kind" of the object and let the expression
infer the kind of itself from its arguments. Function and class can
filter the arguments by their kind, and behave differently according to
the type of itself.
This module defines basic kinds for core objects. Other kinds such as
``ArrayKind`` or ``MatrixKind`` can be found in corresponding modules.
.. notes::
This approach is experimental, and can be replaced or deleted in the future.
See https://github.com/sympy/sympy/pull/20549.
"""
from collections import defaultdict
from .cache import cacheit
from sympy.multipledispatch.dispatcher import (Dispatcher,
ambiguity_warn, ambiguity_register_error_ignore_dup,
str_signature, RaiseNotImplementedError)
class KindMeta(type):
"""
Metaclass for ``Kind``.
Assigns empty ``dict`` as class attribute ``_inst`` for every class,
in order to endow singleton-like behavior.
"""
def __new__(cls, clsname, bases, dct):
dct['_inst'] = {}
return super().__new__(cls, clsname, bases, dct)
class Kind(object, metaclass=KindMeta):
"""
Base class for kinds.
Kind of the object represents the mathematical classification that
the entity falls into. It is expected that functions and classes
recognize and filter the argument by its kind.
Kind of every object must be carefully selected so that it shows the
intention of design. Expressions may have different kind according
to the kind of its arguments. For example, arguments of ``Add``
must have common kind since addition is group operator, and the
resulting ``Add()`` has the same kind.
For the performance, each kind is as broad as possible and is not
based on set theory. For example, ``NumberKind`` includes not only
complex number but expression containing ``S.Infinity`` or ``S.NaN``
which are not strictly number.
Kind may have arguments as parameter. For example, ``MatrixKind()``
may be constructed with one element which represents the kind of its
elements.
``Kind`` behaves in singleton-like fashion. Same signature will
return the same object.
"""
def __new__(cls, *args):
if args in cls._inst:
inst = cls._inst[args]
else:
inst = super().__new__(cls)
cls._inst[args] = inst
return inst
class _UndefinedKind(Kind):
"""
Default kind for all SymPy object. If the kind is not defined for
the object, or if the object cannot infer the kind from its
arguments, this will be returned.
Examples
========
>>> from sympy import Expr
>>> Expr().kind
UndefinedKind
"""
def __new__(cls):
return super().__new__(cls)
def __repr__(self):
return "UndefinedKind"
UndefinedKind = _UndefinedKind()
class _NumberKind(Kind):
"""
Kind for all numeric object.
This kind represents every number, including complex numbers,
infinity and ``S.NaN``. Other objects such as quaternions do not
have this kind.
Most ``Expr`` are initially designed to represent the number, so
this will be the most common kind in SymPy core. For example
``Symbol()``, which represents a scalar, has this kind as long as it
is commutative.
Numbers form a field. Any operation between number-kind objects will
result this kind as well.
Examples
========
>>> from sympy import S, oo, Symbol
>>> S.One.kind
NumberKind
>>> (-oo).kind
NumberKind
>>> S.NaN.kind
NumberKind
Commutative symbol are treated as number.
>>> x = Symbol('x')
>>> x.kind
NumberKind
>>> Symbol('y', commutative=False).kind
UndefinedKind
Operation between numbers results number.
>>> (x+1).kind
NumberKind
See Also
========
sympy.core.expr.Expr.is_Number : check if the object is strictly
subclass of ``Number`` class.
sympy.core.expr.Expr.is_number : check if the object is number
without any free symbol.
"""
def __new__(cls):
return super().__new__(cls)
def __repr__(self):
return "NumberKind"
NumberKind = _NumberKind()
class _BooleanKind(Kind):
"""
Kind for boolean objects.
SymPy's ``S.true``, ``S.false``, and built-in ``True`` and ``False``
have this kind. Boolean number ``1`` and ``0`` are not relevant.
Examples
========
>>> from sympy import S, Q
>>> S.true.kind
BooleanKind
>>> Q.even(3).kind
BooleanKind
"""
def __new__(cls):
return super().__new__(cls)
def __repr__(self):
return "BooleanKind"
BooleanKind = _BooleanKind()
class KindDispatcher:
"""
Dispatcher to select a kind from multiple kinds by binary dispatching.
.. notes::
This approach is experimental, and can be replaced or deleted in
the future.
Explanation
===========
SymPy object's :obj:`sympy.core.kind.Kind()` vaguely represents the
algebraic structure where the object belongs to. Therefore, with
given operation, we can always find a dominating kind among the
different kinds. This class selects the kind by recursive binary
dispatching. If the result cannot be determined, ``UndefinedKind``
is returned.
Examples
========
Multiplication between numbers return number.
>>> from sympy import NumberKind, Mul
>>> Mul._kind_dispatcher(NumberKind, NumberKind)
NumberKind
Multiplication between number and unknown-kind object returns unknown kind.
>>> from sympy import UndefinedKind
>>> Mul._kind_dispatcher(NumberKind, UndefinedKind)
UndefinedKind
Any number and order of kinds is allowed.
>>> Mul._kind_dispatcher(UndefinedKind, NumberKind)
UndefinedKind
>>> Mul._kind_dispatcher(NumberKind, UndefinedKind, NumberKind)
UndefinedKind
Since matrix forms a vector space over scalar field, multiplication
between matrix with numeric element and number returns matrix with
numeric element.
>>> from sympy.matrices import MatrixKind
>>> Mul._kind_dispatcher(MatrixKind(NumberKind), NumberKind)
MatrixKind(NumberKind)
If a matrix with number element and another matrix with unknown-kind
element are multiplied, we know that the result is matrix but the
kind of its elements is unknown.
>>> Mul._kind_dispatcher(MatrixKind(NumberKind), MatrixKind(UndefinedKind))
MatrixKind(UndefinedKind)
Parameters
==========
name : str
commutative : bool, optional
If True, binary dispatch will be automatically registered in
reversed order as well.
doc : str, optional
"""
def __init__(self, name, commutative=False, doc=None):
self.name = name
self.doc = doc
self.commutative = commutative
self._dispatcher = Dispatcher(name)
def __repr__(self):
return "<dispatched %s>" % self.name
def register(self, *types, **kwargs):
"""
Register the binary dispatcher for two kind classes.
If *self.commutative* is ``True``, signature in reversed order is
automatically registered as well.
"""
on_ambiguity = kwargs.pop("on_ambiguity", None)
if not on_ambiguity:
if self.commutative:
on_ambiguity = ambiguity_register_error_ignore_dup
else:
on_ambiguity = ambiguity_warn
kwargs.update(on_ambiguity=on_ambiguity)
if not len(types) == 2:
raise RuntimeError(
"Only binary dispatch is supported, but got %s types: <%s>." % (
len(types), str_signature(types)
))
def _(func):
self._dispatcher.add(types, func, **kwargs)
if self.commutative:
self._dispatcher.add(tuple(reversed(types)), func, **kwargs)
return _
def __call__(self, *args, **kwargs):
if self.commutative:
kinds = frozenset(args)
else:
kinds = []
prev = None
for a in args:
if prev is not a:
kinds.append(a)
prev = a
return self.dispatch_kinds(kinds, **kwargs)
@cacheit
def dispatch_kinds(self, kinds, **kwargs):
# Quick exit for the case where all kinds are same
if len(kinds) == 1:
result, = kinds
if not isinstance(result, Kind):
raise RuntimeError("%s is not a kind." % result)
return result
for i,kind in enumerate(kinds):
if not isinstance(kind, Kind):
raise RuntimeError("%s is not a kind." % kind)
if i == 0:
result = kind
else:
prev_kind = result
t1, t2 = type(prev_kind), type(kind)
k1, k2 = prev_kind, kind
func = self._dispatcher.dispatch(t1, t2)
if func is None and self.commutative:
# try reversed order
func = self._dispatcher.dispatch(t2, t1)
k1, k2 = k2, k1
if func is None:
# unregistered kind relation
result = UndefinedKind
else:
result = func(k1, k2)
if not isinstance(result, Kind):
raise RuntimeError(
"Dispatcher for {!r} and {!r} must return a Kind, but got {!r}".format(
prev_kind, kind, result
))
return result
@property
def __doc__(self):
docs = [
"Kind dispatcher : %s" % self.name,
"Note that support for this is experimental. See the docs for :class:`KindDispatcher` for details"
]
if self.doc:
docs.append(self.doc)
s = "Registered kind classes\n"
s += '=' * len(s)
docs.append(s)
amb_sigs = []
typ_sigs = defaultdict(list)
for sigs in self._dispatcher.ordering[::-1]:
key = self._dispatcher.funcs[sigs]
typ_sigs[key].append(sigs)
for func, sigs in typ_sigs.items():
sigs_str = ', '.join('<%s>' % str_signature(sig) for sig in sigs)
if isinstance(func, RaiseNotImplementedError):
amb_sigs.append(sigs_str)
continue
s = 'Inputs: %s\n' % sigs_str
s += '-' * len(s) + '\n'
if func.__doc__:
s += func.__doc__.strip()
else:
s += func.__name__
docs.append(s)
if amb_sigs:
s = "Ambiguous kind classes\n"
s += '=' * len(s)
docs.append(s)
s = '\n'.join(amb_sigs)
docs.append(s)
return '\n\n'.join(docs)
PK ]ZZZ�K��q* q* sympy/core/logic.py"""Logic expressions handling
NOTE
----
at present this is mainly needed for facts.py, feel free however to improve
this stuff for general purpose.
"""
from __future__ import annotations
from typing import Optional
# Type of a fuzzy bool
FuzzyBool = Optional[bool]
def _torf(args):
"""Return True if all args are True, False if they
are all False, else None.
>>> from sympy.core.logic import _torf
>>> _torf((True, True))
True
>>> _torf((False, False))
False
>>> _torf((True, False))
"""
sawT = sawF = False
for a in args:
if a is True:
if sawF:
return
sawT = True
elif a is False:
if sawT:
return
sawF = True
else:
return
return sawT
def _fuzzy_group(args, quick_exit=False):
"""Return True if all args are True, None if there is any None else False
unless ``quick_exit`` is True (then return None as soon as a second False
is seen.
``_fuzzy_group`` is like ``fuzzy_and`` except that it is more
conservative in returning a False, waiting to make sure that all
arguments are True or False and returning None if any arguments are
None. It also has the capability of permiting only a single False and
returning None if more than one is seen. For example, the presence of a
single transcendental amongst rationals would indicate that the group is
no longer rational; but a second transcendental in the group would make the
determination impossible.
Examples
========
>>> from sympy.core.logic import _fuzzy_group
By default, multiple Falses mean the group is broken:
>>> _fuzzy_group([False, False, True])
False
If multiple Falses mean the group status is unknown then set
`quick_exit` to True so None can be returned when the 2nd False is seen:
>>> _fuzzy_group([False, False, True], quick_exit=True)
But if only a single False is seen then the group is known to
be broken:
>>> _fuzzy_group([False, True, True], quick_exit=True)
False
"""
saw_other = False
for a in args:
if a is True:
continue
if a is None:
return
if quick_exit and saw_other:
return
saw_other = True
return not saw_other
def fuzzy_bool(x):
"""Return True, False or None according to x.
Whereas bool(x) returns True or False, fuzzy_bool allows
for the None value and non-false values (which become None), too.
Examples
========
>>> from sympy.core.logic import fuzzy_bool
>>> from sympy.abc import x
>>> fuzzy_bool(x), fuzzy_bool(None)
(None, None)
>>> bool(x), bool(None)
(True, False)
"""
if x is None:
return None
if x in (True, False):
return bool(x)
def fuzzy_and(args):
"""Return True (all True), False (any False) or None.
Examples
========
>>> from sympy.core.logic import fuzzy_and
>>> from sympy import Dummy
If you had a list of objects to test the commutivity of
and you want the fuzzy_and logic applied, passing an
iterator will allow the commutativity to only be computed
as many times as necessary. With this list, False can be
returned after analyzing the first symbol:
>>> syms = [Dummy(commutative=False), Dummy()]
>>> fuzzy_and(s.is_commutative for s in syms)
False
That False would require less work than if a list of pre-computed
items was sent:
>>> fuzzy_and([s.is_commutative for s in syms])
False
"""
rv = True
for ai in args:
ai = fuzzy_bool(ai)
if ai is False:
return False
if rv: # this will stop updating if a None is ever trapped
rv = ai
return rv
def fuzzy_not(v):
"""
Not in fuzzy logic
Return None if `v` is None else `not v`.
Examples
========
>>> from sympy.core.logic import fuzzy_not
>>> fuzzy_not(True)
False
>>> fuzzy_not(None)
>>> fuzzy_not(False)
True
"""
if v is None:
return v
else:
return not v
def fuzzy_or(args):
"""
Or in fuzzy logic. Returns True (any True), False (all False), or None
See the docstrings of fuzzy_and and fuzzy_not for more info. fuzzy_or is
related to the two by the standard De Morgan's law.
>>> from sympy.core.logic import fuzzy_or
>>> fuzzy_or([True, False])
True
>>> fuzzy_or([True, None])
True
>>> fuzzy_or([False, False])
False
>>> print(fuzzy_or([False, None]))
None
"""
rv = False
for ai in args:
ai = fuzzy_bool(ai)
if ai is True:
return True
if rv is False: # this will stop updating if a None is ever trapped
rv = ai
return rv
def fuzzy_xor(args):
"""Return None if any element of args is not True or False, else
True (if there are an odd number of True elements), else False."""
t = f = 0
for a in args:
ai = fuzzy_bool(a)
if ai:
t += 1
elif ai is False:
f += 1
else:
return
return t % 2 == 1
def fuzzy_nand(args):
"""Return False if all args are True, True if they are all False,
else None."""
return fuzzy_not(fuzzy_and(args))
class Logic:
"""Logical expression"""
# {} 'op' -> LogicClass
op_2class: dict[str, type[Logic]] = {}
def __new__(cls, *args):
obj = object.__new__(cls)
obj.args = args
return obj
def __getnewargs__(self):
return self.args
def __hash__(self):
return hash((type(self).__name__,) + tuple(self.args))
def __eq__(a, b):
if not isinstance(b, type(a)):
return False
else:
return a.args == b.args
def __ne__(a, b):
if not isinstance(b, type(a)):
return True
else:
return a.args != b.args
def __lt__(self, other):
if self.__cmp__(other) == -1:
return True
return False
def __cmp__(self, other):
if type(self) is not type(other):
a = str(type(self))
b = str(type(other))
else:
a = self.args
b = other.args
return (a > b) - (a < b)
def __str__(self):
return '%s(%s)' % (self.__class__.__name__,
', '.join(str(a) for a in self.args))
__repr__ = __str__
@staticmethod
def fromstring(text):
"""Logic from string with space around & and | but none after !.
e.g.
!a & b | c
"""
lexpr = None # current logical expression
schedop = None # scheduled operation
for term in text.split():
# operation symbol
if term in '&|':
if schedop is not None:
raise ValueError(
'double op forbidden: "%s %s"' % (term, schedop))
if lexpr is None:
raise ValueError(
'%s cannot be in the beginning of expression' % term)
schedop = term
continue
if '&' in term or '|' in term:
raise ValueError('& and | must have space around them')
if term[0] == '!':
if len(term) == 1:
raise ValueError('do not include space after "!"')
term = Not(term[1:])
# already scheduled operation, e.g. '&'
if schedop:
lexpr = Logic.op_2class[schedop](lexpr, term)
schedop = None
continue
# this should be atom
if lexpr is not None:
raise ValueError(
'missing op between "%s" and "%s"' % (lexpr, term))
lexpr = term
# let's check that we ended up in correct state
if schedop is not None:
raise ValueError('premature end-of-expression in "%s"' % text)
if lexpr is None:
raise ValueError('"%s" is empty' % text)
# everything looks good now
return lexpr
class AndOr_Base(Logic):
def __new__(cls, *args):
bargs = []
for a in args:
if a == cls.op_x_notx:
return a
elif a == (not cls.op_x_notx):
continue # skip this argument
bargs.append(a)
args = sorted(set(cls.flatten(bargs)), key=hash)
for a in args:
if Not(a) in args:
return cls.op_x_notx
if len(args) == 1:
return args.pop()
elif len(args) == 0:
return not cls.op_x_notx
return Logic.__new__(cls, *args)
@classmethod
def flatten(cls, args):
# quick-n-dirty flattening for And and Or
args_queue = list(args)
res = []
while True:
try:
arg = args_queue.pop(0)
except IndexError:
break
if isinstance(arg, Logic):
if isinstance(arg, cls):
args_queue.extend(arg.args)
continue
res.append(arg)
args = tuple(res)
return args
class And(AndOr_Base):
op_x_notx = False
def _eval_propagate_not(self):
# !(a&b&c ...) == !a | !b | !c ...
return Or(*[Not(a) for a in self.args])
# (a|b|...) & c == (a&c) | (b&c) | ...
def expand(self):
# first locate Or
for i, arg in enumerate(self.args):
if isinstance(arg, Or):
arest = self.args[:i] + self.args[i + 1:]
orterms = [And(*(arest + (a,))) for a in arg.args]
for j in range(len(orterms)):
if isinstance(orterms[j], Logic):
orterms[j] = orterms[j].expand()
res = Or(*orterms)
return res
return self
class Or(AndOr_Base):
op_x_notx = True
def _eval_propagate_not(self):
# !(a|b|c ...) == !a & !b & !c ...
return And(*[Not(a) for a in self.args])
class Not(Logic):
def __new__(cls, arg):
if isinstance(arg, str):
return Logic.__new__(cls, arg)
elif isinstance(arg, bool):
return not arg
elif isinstance(arg, Not):
return arg.args[0]
elif isinstance(arg, Logic):
# XXX this is a hack to expand right from the beginning
arg = arg._eval_propagate_not()
return arg
else:
raise ValueError('Not: unknown argument %r' % (arg,))
@property
def arg(self):
return self.args[0]
Logic.op_2class['&'] = And
Logic.op_2class['|'] = Or
Logic.op_2class['!'] = Not
PK ]ZZZ�f�� � sympy/core/mod.pyfrom .add import Add
from .exprtools import gcd_terms
from .function import Function
from .kind import NumberKind
from .logic import fuzzy_and, fuzzy_not
from .mul import Mul
from .numbers import equal_valued
from .singleton import S
class Mod(Function):
"""Represents a modulo operation on symbolic expressions.
Parameters
==========
p : Expr
Dividend.
q : Expr
Divisor.
Notes
=====
The convention used is the same as Python's: the remainder always has the
same sign as the divisor.
Many objects can be evaluated modulo ``n`` much faster than they can be
evaluated directly (or at all). For this, ``evaluate=False`` is
necessary to prevent eager evaluation:
>>> from sympy import binomial, factorial, Mod, Pow
>>> Mod(Pow(2, 10**16, evaluate=False), 97)
61
>>> Mod(factorial(10**9, evaluate=False), 10**9 + 9)
712524808
>>> Mod(binomial(10**18, 10**12, evaluate=False), (10**5 + 3)**2)
3744312326
Examples
========
>>> from sympy.abc import x, y
>>> x**2 % y
Mod(x**2, y)
>>> _.subs({x: 5, y: 6})
1
"""
kind = NumberKind
@classmethod
def eval(cls, p, q):
def number_eval(p, q):
"""Try to return p % q if both are numbers or +/-p is known
to be less than or equal q.
"""
if q.is_zero:
raise ZeroDivisionError("Modulo by zero")
if p is S.NaN or q is S.NaN or p.is_finite is False or q.is_finite is False:
return S.NaN
if p is S.Zero or p in (q, -q) or (p.is_integer and q == 1):
return S.Zero
if q.is_Number:
if p.is_Number:
return p%q
if q == 2:
if p.is_even:
return S.Zero
elif p.is_odd:
return S.One
if hasattr(p, '_eval_Mod'):
rv = getattr(p, '_eval_Mod')(q)
if rv is not None:
return rv
# by ratio
r = p/q
if r.is_integer:
return S.Zero
try:
d = int(r)
except TypeError:
pass
else:
if isinstance(d, int):
rv = p - d*q
if (rv*q < 0) == True:
rv += q
return rv
# by difference
# -2|q| < p < 2|q|
d = abs(p)
for _ in range(2):
d -= abs(q)
if d.is_negative:
if q.is_positive:
if p.is_positive:
return d + q
elif p.is_negative:
return -d
elif q.is_negative:
if p.is_positive:
return d
elif p.is_negative:
return -d + q
break
rv = number_eval(p, q)
if rv is not None:
return rv
# denest
if isinstance(p, cls):
qinner = p.args[1]
if qinner % q == 0:
return cls(p.args[0], q)
elif (qinner*(q - qinner)).is_nonnegative:
# |qinner| < |q| and have same sign
return p
elif isinstance(-p, cls):
qinner = (-p).args[1]
if qinner % q == 0:
return cls(-(-p).args[0], q)
elif (qinner*(q + qinner)).is_nonpositive:
# |qinner| < |q| and have different sign
return p
elif isinstance(p, Add):
# separating into modulus and non modulus
both_l = non_mod_l, mod_l = [], []
for arg in p.args:
both_l[isinstance(arg, cls)].append(arg)
# if q same for all
if mod_l and all(inner.args[1] == q for inner in mod_l):
net = Add(*non_mod_l) + Add(*[i.args[0] for i in mod_l])
return cls(net, q)
elif isinstance(p, Mul):
# separating into modulus and non modulus
both_l = non_mod_l, mod_l = [], []
for arg in p.args:
both_l[isinstance(arg, cls)].append(arg)
if mod_l and all(inner.args[1] == q for inner in mod_l) and all(t.is_integer for t in p.args) and q.is_integer:
# finding distributive term
non_mod_l = [cls(x, q) for x in non_mod_l]
mod = []
non_mod = []
for j in non_mod_l:
if isinstance(j, cls):
mod.append(j.args[0])
else:
non_mod.append(j)
prod_mod = Mul(*mod)
prod_non_mod = Mul(*non_mod)
prod_mod1 = Mul(*[i.args[0] for i in mod_l])
net = prod_mod1*prod_mod
return prod_non_mod*cls(net, q)
if q.is_Integer and q is not S.One:
if all(t.is_integer for t in p.args):
non_mod_l = [i % q if i.is_Integer else i for i in p.args]
if any(iq is S.Zero for iq in non_mod_l):
return S.Zero
p = Mul(*(non_mod_l + mod_l))
# XXX other possibilities?
from sympy.polys.polyerrors import PolynomialError
from sympy.polys.polytools import gcd
# extract gcd; any further simplification should be done by the user
try:
G = gcd(p, q)
if not equal_valued(G, 1):
p, q = [gcd_terms(i/G, clear=False, fraction=False)
for i in (p, q)]
except PolynomialError: # issue 21373
G = S.One
pwas, qwas = p, q
# simplify terms
# (x + y + 2) % x -> Mod(y + 2, x)
if p.is_Add:
args = []
for i in p.args:
a = cls(i, q)
if a.count(cls) > i.count(cls):
args.append(i)
else:
args.append(a)
if args != list(p.args):
p = Add(*args)
else:
# handle coefficients if they are not Rational
# since those are not handled by factor_terms
# e.g. Mod(.6*x, .3*y) -> 0.3*Mod(2*x, y)
cp, p = p.as_coeff_Mul()
cq, q = q.as_coeff_Mul()
ok = False
if not cp.is_Rational or not cq.is_Rational:
r = cp % cq
if equal_valued(r, 0):
G *= cq
p *= int(cp/cq)
ok = True
if not ok:
p = cp*p
q = cq*q
# simple -1 extraction
if p.could_extract_minus_sign() and q.could_extract_minus_sign():
G, p, q = [-i for i in (G, p, q)]
# check again to see if p and q can now be handled as numbers
rv = number_eval(p, q)
if rv is not None:
return rv*G
# put 1.0 from G on inside
if G.is_Float and equal_valued(G, 1):
p *= G
return cls(p, q, evaluate=False)
elif G.is_Mul and G.args[0].is_Float and equal_valued(G.args[0], 1):
p = G.args[0]*p
G = Mul._from_args(G.args[1:])
return G*cls(p, q, evaluate=(p, q) != (pwas, qwas))
def _eval_is_integer(self):
p, q = self.args
if fuzzy_and([p.is_integer, q.is_integer, fuzzy_not(q.is_zero)]):
return True
def _eval_is_nonnegative(self):
if self.args[1].is_positive:
return True
def _eval_is_nonpositive(self):
if self.args[1].is_negative:
return True
def _eval_rewrite_as_floor(self, a, b, **kwargs):
from sympy.functions.elementary.integers import floor
return a - b*floor(a/b)
def _eval_as_leading_term(self, x, logx=None, cdir=0):
from sympy.functions.elementary.integers import floor
return self.rewrite(floor)._eval_as_leading_term(x, logx=logx, cdir=cdir)
def _eval_nseries(self, x, n, logx, cdir=0):
from sympy.functions.elementary.integers import floor
return self.rewrite(floor)._eval_nseries(x, n, logx=logx, cdir=cdir)
PK ]ZZZG `)�2 �2 sympy/core/mul.pyfrom typing import Tuple as tTuple
from collections import defaultdict
from functools import reduce
from itertools import product
import operator
from .sympify import sympify
from .basic import Basic, _args_sortkey
from .singleton import S
from .operations import AssocOp, AssocOpDispatcher
from .cache import cacheit
from .intfunc import integer_nthroot, trailing
from .logic import fuzzy_not, _fuzzy_group
from .expr import Expr
from .parameters import global_parameters
from .kind import KindDispatcher
from .traversal import bottom_up
from sympy.utilities.iterables import sift
# internal marker to indicate:
# "there are still non-commutative objects -- don't forget to process them"
class NC_Marker:
is_Order = False
is_Mul = False
is_Number = False
is_Poly = False
is_commutative = False
def _mulsort(args):
# in-place sorting of args
args.sort(key=_args_sortkey)
def _unevaluated_Mul(*args):
"""Return a well-formed unevaluated Mul: Numbers are collected and
put in slot 0, any arguments that are Muls will be flattened, and args
are sorted. Use this when args have changed but you still want to return
an unevaluated Mul.
Examples
========
>>> from sympy.core.mul import _unevaluated_Mul as uMul
>>> from sympy import S, sqrt, Mul
>>> from sympy.abc import x
>>> a = uMul(*[S(3.0), x, S(2)])
>>> a.args[0]
6.00000000000000
>>> a.args[1]
x
Two unevaluated Muls with the same arguments will
always compare as equal during testing:
>>> m = uMul(sqrt(2), sqrt(3))
>>> m == uMul(sqrt(3), sqrt(2))
True
>>> u = Mul(sqrt(3), sqrt(2), evaluate=False)
>>> m == uMul(u)
True
>>> m == Mul(*m.args)
False
"""
args = list(args)
newargs = []
ncargs = []
co = S.One
while args:
a = args.pop()
if a.is_Mul:
c, nc = a.args_cnc()
args.extend(c)
if nc:
ncargs.append(Mul._from_args(nc))
elif a.is_Number:
co *= a
else:
newargs.append(a)
_mulsort(newargs)
if co is not S.One:
newargs.insert(0, co)
if ncargs:
newargs.append(Mul._from_args(ncargs))
return Mul._from_args(newargs)
class Mul(Expr, AssocOp):
"""
Expression representing multiplication operation for algebraic field.
.. deprecated:: 1.7
Using arguments that aren't subclasses of :class:`~.Expr` in core
operators (:class:`~.Mul`, :class:`~.Add`, and :class:`~.Pow`) is
deprecated. See :ref:`non-expr-args-deprecated` for details.
Every argument of ``Mul()`` must be ``Expr``. Infix operator ``*``
on most scalar objects in SymPy calls this class.
Another use of ``Mul()`` is to represent the structure of abstract
multiplication so that its arguments can be substituted to return
different class. Refer to examples section for this.
``Mul()`` evaluates the argument unless ``evaluate=False`` is passed.
The evaluation logic includes:
1. Flattening
``Mul(x, Mul(y, z))`` -> ``Mul(x, y, z)``
2. Identity removing
``Mul(x, 1, y)`` -> ``Mul(x, y)``
3. Exponent collecting by ``.as_base_exp()``
``Mul(x, x**2)`` -> ``Pow(x, 3)``
4. Term sorting
``Mul(y, x, 2)`` -> ``Mul(2, x, y)``
Since multiplication can be vector space operation, arguments may
have the different :obj:`sympy.core.kind.Kind()`. Kind of the
resulting object is automatically inferred.
Examples
========
>>> from sympy import Mul
>>> from sympy.abc import x, y
>>> Mul(x, 1)
x
>>> Mul(x, x)
x**2
If ``evaluate=False`` is passed, result is not evaluated.
>>> Mul(1, 2, evaluate=False)
1*2
>>> Mul(x, x, evaluate=False)
x*x
``Mul()`` also represents the general structure of multiplication
operation.
>>> from sympy import MatrixSymbol
>>> A = MatrixSymbol('A', 2,2)
>>> expr = Mul(x,y).subs({y:A})
>>> expr
x*A
>>> type(expr)
<class 'sympy.matrices.expressions.matmul.MatMul'>
See Also
========
MatMul
"""
__slots__ = ()
args: tTuple[Expr, ...]
is_Mul = True
_args_type = Expr
_kind_dispatcher = KindDispatcher("Mul_kind_dispatcher", commutative=True)
@property
def kind(self):
arg_kinds = (a.kind for a in self.args)
return self._kind_dispatcher(*arg_kinds)
def could_extract_minus_sign(self):
if self == (-self):
return False # e.g. zoo*x == -zoo*x
c = self.args[0]
return c.is_Number and c.is_extended_negative
def __neg__(self):
c, args = self.as_coeff_mul()
if args[0] is not S.ComplexInfinity:
c = -c
if c is not S.One:
if args[0].is_Number:
args = list(args)
if c is S.NegativeOne:
args[0] = -args[0]
else:
args[0] *= c
else:
args = (c,) + args
return self._from_args(args, self.is_commutative)
@classmethod
def flatten(cls, seq):
"""Return commutative, noncommutative and order arguments by
combining related terms.
Notes
=====
* In an expression like ``a*b*c``, Python process this through SymPy
as ``Mul(Mul(a, b), c)``. This can have undesirable consequences.
- Sometimes terms are not combined as one would like:
{c.f. https://github.com/sympy/sympy/issues/4596}
>>> from sympy import Mul, sqrt
>>> from sympy.abc import x, y, z
>>> 2*(x + 1) # this is the 2-arg Mul behavior
2*x + 2
>>> y*(x + 1)*2
2*y*(x + 1)
>>> 2*(x + 1)*y # 2-arg result will be obtained first
y*(2*x + 2)
>>> Mul(2, x + 1, y) # all 3 args simultaneously processed
2*y*(x + 1)
>>> 2*((x + 1)*y) # parentheses can control this behavior
2*y*(x + 1)
Powers with compound bases may not find a single base to
combine with unless all arguments are processed at once.
Post-processing may be necessary in such cases.
{c.f. https://github.com/sympy/sympy/issues/5728}
>>> a = sqrt(x*sqrt(y))
>>> a**3
(x*sqrt(y))**(3/2)
>>> Mul(a,a,a)
(x*sqrt(y))**(3/2)
>>> a*a*a
x*sqrt(y)*sqrt(x*sqrt(y))
>>> _.subs(a.base, z).subs(z, a.base)
(x*sqrt(y))**(3/2)
- If more than two terms are being multiplied then all the
previous terms will be re-processed for each new argument.
So if each of ``a``, ``b`` and ``c`` were :class:`Mul`
expression, then ``a*b*c`` (or building up the product
with ``*=``) will process all the arguments of ``a`` and
``b`` twice: once when ``a*b`` is computed and again when
``c`` is multiplied.
Using ``Mul(a, b, c)`` will process all arguments once.
* The results of Mul are cached according to arguments, so flatten
will only be called once for ``Mul(a, b, c)``. If you can
structure a calculation so the arguments are most likely to be
repeats then this can save time in computing the answer. For
example, say you had a Mul, M, that you wished to divide by ``d[i]``
and multiply by ``n[i]`` and you suspect there are many repeats
in ``n``. It would be better to compute ``M*n[i]/d[i]`` rather
than ``M/d[i]*n[i]`` since every time n[i] is a repeat, the
product, ``M*n[i]`` will be returned without flattening -- the
cached value will be returned. If you divide by the ``d[i]``
first (and those are more unique than the ``n[i]``) then that will
create a new Mul, ``M/d[i]`` the args of which will be traversed
again when it is multiplied by ``n[i]``.
{c.f. https://github.com/sympy/sympy/issues/5706}
This consideration is moot if the cache is turned off.
NB
--
The validity of the above notes depends on the implementation
details of Mul and flatten which may change at any time. Therefore,
you should only consider them when your code is highly performance
sensitive.
Removal of 1 from the sequence is already handled by AssocOp.__new__.
"""
from sympy.calculus.accumulationbounds import AccumBounds
from sympy.matrices.expressions import MatrixExpr
rv = None
if len(seq) == 2:
a, b = seq
if b.is_Rational:
a, b = b, a
seq = [a, b]
assert a is not S.One
if a.is_Rational and not a.is_zero:
r, b = b.as_coeff_Mul()
if b.is_Add:
if r is not S.One: # 2-arg hack
# leave the Mul as a Mul?
ar = a*r
if ar is S.One:
arb = b
else:
arb = cls(a*r, b, evaluate=False)
rv = [arb], [], None
elif global_parameters.distribute and b.is_commutative:
newb = Add(*[_keep_coeff(a, bi) for bi in b.args])
rv = [newb], [], None
if rv:
return rv
# apply associativity, separate commutative part of seq
c_part = [] # out: commutative factors
nc_part = [] # out: non-commutative factors
nc_seq = []
coeff = S.One # standalone term
# e.g. 3 * ...
c_powers = [] # (base,exp) n
# e.g. (x,n) for x
num_exp = [] # (num-base, exp) y
# e.g. (3, y) for ... * 3 * ...
neg1e = S.Zero # exponent on -1 extracted from Number-based Pow and I
pnum_rat = {} # (num-base, Rat-exp) 1/2
# e.g. (3, 1/2) for ... * 3 * ...
order_symbols = None
# --- PART 1 ---
#
# "collect powers and coeff":
#
# o coeff
# o c_powers
# o num_exp
# o neg1e
# o pnum_rat
#
# NOTE: this is optimized for all-objects-are-commutative case
for o in seq:
# O(x)
if o.is_Order:
o, order_symbols = o.as_expr_variables(order_symbols)
# Mul([...])
if o.is_Mul:
if o.is_commutative:
seq.extend(o.args) # XXX zerocopy?
else:
# NCMul can have commutative parts as well
for q in o.args:
if q.is_commutative:
seq.append(q)
else:
nc_seq.append(q)
# append non-commutative marker, so we don't forget to
# process scheduled non-commutative objects
seq.append(NC_Marker)
continue
# 3
elif o.is_Number:
if o is S.NaN or coeff is S.ComplexInfinity and o.is_zero:
# we know for sure the result will be nan
return [S.NaN], [], None
elif coeff.is_Number or isinstance(coeff, AccumBounds): # it could be zoo
coeff *= o
if coeff is S.NaN:
# we know for sure the result will be nan
return [S.NaN], [], None
continue
elif isinstance(o, AccumBounds):
coeff = o.__mul__(coeff)
continue
elif o is S.ComplexInfinity:
if not coeff:
# 0 * zoo = NaN
return [S.NaN], [], None
coeff = S.ComplexInfinity
continue
elif o is S.ImaginaryUnit:
neg1e += S.Half
continue
elif o.is_commutative:
# e
# o = b
b, e = o.as_base_exp()
# y
# 3
if o.is_Pow:
if b.is_Number:
# get all the factors with numeric base so they can be
# combined below, but don't combine negatives unless
# the exponent is an integer
if e.is_Rational:
if e.is_Integer:
coeff *= Pow(b, e) # it is an unevaluated power
continue
elif e.is_negative: # also a sign of an unevaluated power
seq.append(Pow(b, e))
continue
elif b.is_negative:
neg1e += e
b = -b
if b is not S.One:
pnum_rat.setdefault(b, []).append(e)
continue
elif b.is_positive or e.is_integer:
num_exp.append((b, e))
continue
c_powers.append((b, e))
# NON-COMMUTATIVE
# TODO: Make non-commutative exponents not combine automatically
else:
if o is not NC_Marker:
nc_seq.append(o)
# process nc_seq (if any)
while nc_seq:
o = nc_seq.pop(0)
if not nc_part:
nc_part.append(o)
continue
# b c b+c
# try to combine last terms: a * a -> a
o1 = nc_part.pop()
b1, e1 = o1.as_base_exp()
b2, e2 = o.as_base_exp()
new_exp = e1 + e2
# Only allow powers to combine if the new exponent is
# not an Add. This allow things like a**2*b**3 == a**5
# if a.is_commutative == False, but prohibits
# a**x*a**y and x**a*x**b from combining (x,y commute).
if b1 == b2 and (not new_exp.is_Add):
o12 = b1 ** new_exp
# now o12 could be a commutative object
if o12.is_commutative:
seq.append(o12)
continue
else:
nc_seq.insert(0, o12)
else:
nc_part.extend([o1, o])
# We do want a combined exponent if it would not be an Add, such as
# y 2y 3y
# x * x -> x
# We determine if two exponents have the same term by using
# as_coeff_Mul.
#
# Unfortunately, this isn't smart enough to consider combining into
# exponents that might already be adds, so things like:
# z - y y
# x * x will be left alone. This is because checking every possible
# combination can slow things down.
# gather exponents of common bases...
def _gather(c_powers):
common_b = {} # b:e
for b, e in c_powers:
co = e.as_coeff_Mul()
common_b.setdefault(b, {}).setdefault(
co[1], []).append(co[0])
for b, d in common_b.items():
for di, li in d.items():
d[di] = Add(*li)
new_c_powers = []
for b, e in common_b.items():
new_c_powers.extend([(b, c*t) for t, c in e.items()])
return new_c_powers
# in c_powers
c_powers = _gather(c_powers)
# and in num_exp
num_exp = _gather(num_exp)
# --- PART 2 ---
#
# o process collected powers (x**0 -> 1; x**1 -> x; otherwise Pow)
# o combine collected powers (2**x * 3**x -> 6**x)
# with numeric base
# ................................
# now we have:
# - coeff:
# - c_powers: (b, e)
# - num_exp: (2, e)
# - pnum_rat: {(1/3, [1/3, 2/3, 1/4])}
# 0 1
# x -> 1 x -> x
# this should only need to run twice; if it fails because
# it needs to be run more times, perhaps this should be
# changed to a "while True" loop -- the only reason it
# isn't such now is to allow a less-than-perfect result to
# be obtained rather than raising an error or entering an
# infinite loop
for i in range(2):
new_c_powers = []
changed = False
for b, e in c_powers:
if e.is_zero:
# canceling out infinities yields NaN
if (b.is_Add or b.is_Mul) and any(infty in b.args
for infty in (S.ComplexInfinity, S.Infinity,
S.NegativeInfinity)):
return [S.NaN], [], None
continue
if e is S.One:
if b.is_Number:
coeff *= b
continue
p = b
if e is not S.One:
p = Pow(b, e)
# check to make sure that the base doesn't change
# after exponentiation; to allow for unevaluated
# Pow, we only do so if b is not already a Pow
if p.is_Pow and not b.is_Pow:
bi = b
b, e = p.as_base_exp()
if b != bi:
changed = True
c_part.append(p)
new_c_powers.append((b, e))
# there might have been a change, but unless the base
# matches some other base, there is nothing to do
if changed and len({
b for b, e in new_c_powers}) != len(new_c_powers):
# start over again
c_part = []
c_powers = _gather(new_c_powers)
else:
break
# x x x
# 2 * 3 -> 6
inv_exp_dict = {} # exp:Mul(num-bases) x x
# e.g. x:6 for ... * 2 * 3 * ...
for b, e in num_exp:
inv_exp_dict.setdefault(e, []).append(b)
for e, b in inv_exp_dict.items():
inv_exp_dict[e] = cls(*b)
c_part.extend([Pow(b, e) for e, b in inv_exp_dict.items() if e])
# b, e -> e' = sum(e), b
# {(1/5, [1/3]), (1/2, [1/12, 1/4]} -> {(1/3, [1/5, 1/2])}
comb_e = {}
for b, e in pnum_rat.items():
comb_e.setdefault(Add(*e), []).append(b)
del pnum_rat
# process them, reducing exponents to values less than 1
# and updating coeff if necessary else adding them to
# num_rat for further processing
num_rat = []
for e, b in comb_e.items():
b = cls(*b)
if e.q == 1:
coeff *= Pow(b, e)
continue
if e.p > e.q:
e_i, ep = divmod(e.p, e.q)
coeff *= Pow(b, e_i)
e = Rational(ep, e.q)
num_rat.append((b, e))
del comb_e
# extract gcd of bases in num_rat
# 2**(1/3)*6**(1/4) -> 2**(1/3+1/4)*3**(1/4)
pnew = defaultdict(list)
i = 0 # steps through num_rat which may grow
while i < len(num_rat):
bi, ei = num_rat[i]
if bi == 1:
i += 1
continue
grow = []
for j in range(i + 1, len(num_rat)):
bj, ej = num_rat[j]
g = bi.gcd(bj)
if g is not S.One:
# 4**r1*6**r2 -> 2**(r1+r2) * 2**r1 * 3**r2
# this might have a gcd with something else
e = ei + ej
if e.q == 1:
coeff *= Pow(g, e)
else:
if e.p > e.q:
e_i, ep = divmod(e.p, e.q) # change e in place
coeff *= Pow(g, e_i)
e = Rational(ep, e.q)
grow.append((g, e))
# update the jth item
num_rat[j] = (bj/g, ej)
# update bi that we are checking with
bi = bi/g
if bi is S.One:
break
if bi is not S.One:
obj = Pow(bi, ei)
if obj.is_Number:
coeff *= obj
else:
# changes like sqrt(12) -> 2*sqrt(3)
for obj in Mul.make_args(obj):
if obj.is_Number:
coeff *= obj
else:
assert obj.is_Pow
bi, ei = obj.args
pnew[ei].append(bi)
num_rat.extend(grow)
i += 1
# combine bases of the new powers
for e, b in pnew.items():
pnew[e] = cls(*b)
# handle -1 and I
if neg1e:
# treat I as (-1)**(1/2) and compute -1's total exponent
p, q = neg1e.as_numer_denom()
# if the integer part is odd, extract -1
n, p = divmod(p, q)
if n % 2:
coeff = -coeff
# if it's a multiple of 1/2 extract I
if q == 2:
c_part.append(S.ImaginaryUnit)
elif p:
# see if there is any positive base this power of
# -1 can join
neg1e = Rational(p, q)
for e, b in pnew.items():
if e == neg1e and b.is_positive:
pnew[e] = -b
break
else:
# keep it separate; we've already evaluated it as
# much as possible so evaluate=False
c_part.append(Pow(S.NegativeOne, neg1e, evaluate=False))
# add all the pnew powers
c_part.extend([Pow(b, e) for e, b in pnew.items()])
# oo, -oo
if coeff in (S.Infinity, S.NegativeInfinity):
def _handle_for_oo(c_part, coeff_sign):
new_c_part = []
for t in c_part:
if t.is_extended_positive:
continue
if t.is_extended_negative:
coeff_sign *= -1
continue
new_c_part.append(t)
return new_c_part, coeff_sign
c_part, coeff_sign = _handle_for_oo(c_part, 1)
nc_part, coeff_sign = _handle_for_oo(nc_part, coeff_sign)
coeff *= coeff_sign
# zoo
if coeff is S.ComplexInfinity:
# zoo might be
# infinite_real + bounded_im
# bounded_real + infinite_im
# infinite_real + infinite_im
# and non-zero real or imaginary will not change that status.
c_part = [c for c in c_part if not (fuzzy_not(c.is_zero) and
c.is_extended_real is not None)]
nc_part = [c for c in nc_part if not (fuzzy_not(c.is_zero) and
c.is_extended_real is not None)]
# 0
elif coeff.is_zero:
# we know for sure the result will be 0 except the multiplicand
# is infinity or a matrix
if any(isinstance(c, MatrixExpr) for c in nc_part):
return [coeff], nc_part, order_symbols
if any(c.is_finite == False for c in c_part):
return [S.NaN], [], order_symbols
return [coeff], [], order_symbols
# check for straggling Numbers that were produced
_new = []
for i in c_part:
if i.is_Number:
coeff *= i
else:
_new.append(i)
c_part = _new
# order commutative part canonically
_mulsort(c_part)
# current code expects coeff to be always in slot-0
if coeff is not S.One:
c_part.insert(0, coeff)
# we are done
if (global_parameters.distribute and not nc_part and len(c_part) == 2 and
c_part[0].is_Number and c_part[0].is_finite and c_part[1].is_Add):
# 2*(1+a) -> 2 + 2 * a
coeff = c_part[0]
c_part = [Add(*[coeff*f for f in c_part[1].args])]
return c_part, nc_part, order_symbols
def _eval_power(self, e):
# don't break up NC terms: (A*B)**3 != A**3*B**3, it is A*B*A*B*A*B
cargs, nc = self.args_cnc(split_1=False)
if e.is_Integer:
return Mul(*[Pow(b, e, evaluate=False) for b in cargs]) * \
Pow(Mul._from_args(nc), e, evaluate=False)
if e.is_Rational and e.q == 2:
if self.is_imaginary:
a = self.as_real_imag()[1]
if a.is_Rational:
n, d = abs(a/2).as_numer_denom()
n, t = integer_nthroot(n, 2)
if t:
d, t = integer_nthroot(d, 2)
if t:
from sympy.functions.elementary.complexes import sign
r = sympify(n)/d
return _unevaluated_Mul(r**e.p, (1 + sign(a)*S.ImaginaryUnit)**e.p)
p = Pow(self, e, evaluate=False)
if e.is_Rational or e.is_Float:
return p._eval_expand_power_base()
return p
@classmethod
def class_key(cls):
return 3, 0, cls.__name__
def _eval_evalf(self, prec):
c, m = self.as_coeff_Mul()
if c is S.NegativeOne:
if m.is_Mul:
rv = -AssocOp._eval_evalf(m, prec)
else:
mnew = m._eval_evalf(prec)
if mnew is not None:
m = mnew
rv = -m
else:
rv = AssocOp._eval_evalf(self, prec)
if rv.is_number:
return rv.expand()
return rv
@property
def _mpc_(self):
"""
Convert self to an mpmath mpc if possible
"""
from .numbers import Float
im_part, imag_unit = self.as_coeff_Mul()
if imag_unit is not S.ImaginaryUnit:
# ValueError may seem more reasonable but since it's a @property,
# we need to use AttributeError to keep from confusing things like
# hasattr.
raise AttributeError("Cannot convert Mul to mpc. Must be of the form Number*I")
return (Float(0)._mpf_, Float(im_part)._mpf_)
@cacheit
def as_two_terms(self):
"""Return head and tail of self.
This is the most efficient way to get the head and tail of an
expression.
- if you want only the head, use self.args[0];
- if you want to process the arguments of the tail then use
self.as_coef_mul() which gives the head and a tuple containing
the arguments of the tail when treated as a Mul.
- if you want the coefficient when self is treated as an Add
then use self.as_coeff_add()[0]
Examples
========
>>> from sympy.abc import x, y
>>> (3*x*y).as_two_terms()
(3, x*y)
"""
args = self.args
if len(args) == 1:
return S.One, self
elif len(args) == 2:
return args
else:
return args[0], self._new_rawargs(*args[1:])
@cacheit
def as_coeff_mul(self, *deps, rational=True, **kwargs):
if deps:
l1, l2 = sift(self.args, lambda x: x.has(*deps), binary=True)
return self._new_rawargs(*l2), tuple(l1)
args = self.args
if args[0].is_Number:
if not rational or args[0].is_Rational:
return args[0], args[1:]
elif args[0].is_extended_negative:
return S.NegativeOne, (-args[0],) + args[1:]
return S.One, args
def as_coeff_Mul(self, rational=False):
"""
Efficiently extract the coefficient of a product.
"""
coeff, args = self.args[0], self.args[1:]
if coeff.is_Number:
if not rational or coeff.is_Rational:
if len(args) == 1:
return coeff, args[0]
else:
return coeff, self._new_rawargs(*args)
elif coeff.is_extended_negative:
return S.NegativeOne, self._new_rawargs(*((-coeff,) + args))
return S.One, self
def as_real_imag(self, deep=True, **hints):
from sympy.functions.elementary.complexes import Abs, im, re
other = []
coeffr = []
coeffi = []
addterms = S.One
for a in self.args:
r, i = a.as_real_imag()
if i.is_zero:
coeffr.append(r)
elif r.is_zero:
coeffi.append(i*S.ImaginaryUnit)
elif a.is_commutative:
aconj = a.conjugate() if other else None
# search for complex conjugate pairs:
for i, x in enumerate(other):
if x == aconj:
coeffr.append(Abs(x)**2)
del other[i]
break
else:
if a.is_Add:
addterms *= a
else:
other.append(a)
else:
other.append(a)
m = self.func(*other)
if hints.get('ignore') == m:
return
if len(coeffi) % 2:
imco = im(coeffi.pop(0))
# all other pairs make a real factor; they will be
# put into reco below
else:
imco = S.Zero
reco = self.func(*(coeffr + coeffi))
r, i = (reco*re(m), reco*im(m))
if addterms == 1:
if m == 1:
if imco.is_zero:
return (reco, S.Zero)
else:
return (S.Zero, reco*imco)
if imco is S.Zero:
return (r, i)
return (-imco*i, imco*r)
from .function import expand_mul
addre, addim = expand_mul(addterms, deep=False).as_real_imag()
if imco is S.Zero:
return (r*addre - i*addim, i*addre + r*addim)
else:
r, i = -imco*i, imco*r
return (r*addre - i*addim, r*addim + i*addre)
@staticmethod
def _expandsums(sums):
"""
Helper function for _eval_expand_mul.
sums must be a list of instances of Basic.
"""
L = len(sums)
if L == 1:
return sums[0].args
terms = []
left = Mul._expandsums(sums[:L//2])
right = Mul._expandsums(sums[L//2:])
terms = [Mul(a, b) for a in left for b in right]
added = Add(*terms)
return Add.make_args(added) # it may have collapsed down to one term
def _eval_expand_mul(self, **hints):
from sympy.simplify.radsimp import fraction
# Handle things like 1/(x*(x + 1)), which are automatically converted
# to 1/x*1/(x + 1)
expr = self
# default matches fraction's default
n, d = fraction(expr, hints.get('exact', False))
if d.is_Mul:
n, d = [i._eval_expand_mul(**hints) if i.is_Mul else i
for i in (n, d)]
expr = n/d
if not expr.is_Mul:
return expr
plain, sums, rewrite = [], [], False
for factor in expr.args:
if factor.is_Add:
sums.append(factor)
rewrite = True
else:
if factor.is_commutative:
plain.append(factor)
else:
sums.append(Basic(factor)) # Wrapper
if not rewrite:
return expr
else:
plain = self.func(*plain)
if sums:
deep = hints.get("deep", False)
terms = self.func._expandsums(sums)
args = []
for term in terms:
t = self.func(plain, term)
if t.is_Mul and any(a.is_Add for a in t.args) and deep:
t = t._eval_expand_mul()
args.append(t)
return Add(*args)
else:
return plain
@cacheit
def _eval_derivative(self, s):
args = list(self.args)
terms = []
for i in range(len(args)):
d = args[i].diff(s)
if d:
# Note: reduce is used in step of Mul as Mul is unable to
# handle subtypes and operation priority:
terms.append(reduce(lambda x, y: x*y, (args[:i] + [d] + args[i + 1:]), S.One))
return Add.fromiter(terms)
@cacheit
def _eval_derivative_n_times(self, s, n):
from .function import AppliedUndef
from .symbol import Symbol, symbols, Dummy
if not isinstance(s, (AppliedUndef, Symbol)):
# other types of s may not be well behaved, e.g.
# (cos(x)*sin(y)).diff([[x, y, z]])
return super()._eval_derivative_n_times(s, n)
from .numbers import Integer
args = self.args
m = len(args)
if isinstance(n, (int, Integer)):
# https://en.wikipedia.org/wiki/General_Leibniz_rule#More_than_two_factors
terms = []
from sympy.ntheory.multinomial import multinomial_coefficients_iterator
for kvals, c in multinomial_coefficients_iterator(m, n):
p = Mul(*[arg.diff((s, k)) for k, arg in zip(kvals, args)])
terms.append(c * p)
return Add(*terms)
from sympy.concrete.summations import Sum
from sympy.functions.combinatorial.factorials import factorial
from sympy.functions.elementary.miscellaneous import Max
kvals = symbols("k1:%i" % m, cls=Dummy)
klast = n - sum(kvals)
nfact = factorial(n)
e, l = (# better to use the multinomial?
nfact/prod(map(factorial, kvals))/factorial(klast)*\
Mul(*[args[t].diff((s, kvals[t])) for t in range(m-1)])*\
args[-1].diff((s, Max(0, klast))),
[(k, 0, n) for k in kvals])
return Sum(e, *l)
def _eval_difference_delta(self, n, step):
from sympy.series.limitseq import difference_delta as dd
arg0 = self.args[0]
rest = Mul(*self.args[1:])
return (arg0.subs(n, n + step) * dd(rest, n, step) + dd(arg0, n, step) *
rest)
def _matches_simple(self, expr, repl_dict):
# handle (w*3).matches('x*5') -> {w: x*5/3}
coeff, terms = self.as_coeff_Mul()
terms = Mul.make_args(terms)
if len(terms) == 1:
newexpr = self.__class__._combine_inverse(expr, coeff)
return terms[0].matches(newexpr, repl_dict)
return
def matches(self, expr, repl_dict=None, old=False):
expr = sympify(expr)
if self.is_commutative and expr.is_commutative:
return self._matches_commutative(expr, repl_dict, old)
elif self.is_commutative is not expr.is_commutative:
return None
# Proceed only if both both expressions are non-commutative
c1, nc1 = self.args_cnc()
c2, nc2 = expr.args_cnc()
c1, c2 = [c or [1] for c in [c1, c2]]
# TODO: Should these be self.func?
comm_mul_self = Mul(*c1)
comm_mul_expr = Mul(*c2)
repl_dict = comm_mul_self.matches(comm_mul_expr, repl_dict, old)
# If the commutative arguments didn't match and aren't equal, then
# then the expression as a whole doesn't match
if not repl_dict and c1 != c2:
return None
# Now match the non-commutative arguments, expanding powers to
# multiplications
nc1 = Mul._matches_expand_pows(nc1)
nc2 = Mul._matches_expand_pows(nc2)
repl_dict = Mul._matches_noncomm(nc1, nc2, repl_dict)
return repl_dict or None
@staticmethod
def _matches_expand_pows(arg_list):
new_args = []
for arg in arg_list:
if arg.is_Pow and arg.exp > 0:
new_args.extend([arg.base] * arg.exp)
else:
new_args.append(arg)
return new_args
@staticmethod
def _matches_noncomm(nodes, targets, repl_dict=None):
"""Non-commutative multiplication matcher.
`nodes` is a list of symbols within the matcher multiplication
expression, while `targets` is a list of arguments in the
multiplication expression being matched against.
"""
if repl_dict is None:
repl_dict = {}
else:
repl_dict = repl_dict.copy()
# List of possible future states to be considered
agenda = []
# The current matching state, storing index in nodes and targets
state = (0, 0)
node_ind, target_ind = state
# Mapping between wildcard indices and the index ranges they match
wildcard_dict = {}
while target_ind < len(targets) and node_ind < len(nodes):
node = nodes[node_ind]
if node.is_Wild:
Mul._matches_add_wildcard(wildcard_dict, state)
states_matches = Mul._matches_new_states(wildcard_dict, state,
nodes, targets)
if states_matches:
new_states, new_matches = states_matches
agenda.extend(new_states)
if new_matches:
for match in new_matches:
repl_dict[match] = new_matches[match]
if not agenda:
return None
else:
state = agenda.pop()
node_ind, target_ind = state
return repl_dict
@staticmethod
def _matches_add_wildcard(dictionary, state):
node_ind, target_ind = state
if node_ind in dictionary:
begin, end = dictionary[node_ind]
dictionary[node_ind] = (begin, target_ind)
else:
dictionary[node_ind] = (target_ind, target_ind)
@staticmethod
def _matches_new_states(dictionary, state, nodes, targets):
node_ind, target_ind = state
node = nodes[node_ind]
target = targets[target_ind]
# Don't advance at all if we've exhausted the targets but not the nodes
if target_ind >= len(targets) - 1 and node_ind < len(nodes) - 1:
return None
if node.is_Wild:
match_attempt = Mul._matches_match_wilds(dictionary, node_ind,
nodes, targets)
if match_attempt:
# If the same node has been matched before, don't return
# anything if the current match is diverging from the previous
# match
other_node_inds = Mul._matches_get_other_nodes(dictionary,
nodes, node_ind)
for ind in other_node_inds:
other_begin, other_end = dictionary[ind]
curr_begin, curr_end = dictionary[node_ind]
other_targets = targets[other_begin:other_end + 1]
current_targets = targets[curr_begin:curr_end + 1]
for curr, other in zip(current_targets, other_targets):
if curr != other:
return None
# A wildcard node can match more than one target, so only the
# target index is advanced
new_state = [(node_ind, target_ind + 1)]
# Only move on to the next node if there is one
if node_ind < len(nodes) - 1:
new_state.append((node_ind + 1, target_ind + 1))
return new_state, match_attempt
else:
# If we're not at a wildcard, then make sure we haven't exhausted
# nodes but not targets, since in this case one node can only match
# one target
if node_ind >= len(nodes) - 1 and target_ind < len(targets) - 1:
return None
match_attempt = node.matches(target)
if match_attempt:
return [(node_ind + 1, target_ind + 1)], match_attempt
elif node == target:
return [(node_ind + 1, target_ind + 1)], None
else:
return None
@staticmethod
def _matches_match_wilds(dictionary, wildcard_ind, nodes, targets):
"""Determine matches of a wildcard with sub-expression in `target`."""
wildcard = nodes[wildcard_ind]
begin, end = dictionary[wildcard_ind]
terms = targets[begin:end + 1]
# TODO: Should this be self.func?
mult = Mul(*terms) if len(terms) > 1 else terms[0]
return wildcard.matches(mult)
@staticmethod
def _matches_get_other_nodes(dictionary, nodes, node_ind):
"""Find other wildcards that may have already been matched."""
ind_node = nodes[node_ind]
return [ind for ind in dictionary if nodes[ind] == ind_node]
@staticmethod
def _combine_inverse(lhs, rhs):
"""
Returns lhs/rhs, but treats arguments like symbols, so things
like oo/oo return 1 (instead of a nan) and ``I`` behaves like
a symbol instead of sqrt(-1).
"""
from sympy.simplify.simplify import signsimp
from .symbol import Dummy
if lhs == rhs:
return S.One
def check(l, r):
if l.is_Float and r.is_comparable:
# if both objects are added to 0 they will share the same "normalization"
# and are more likely to compare the same. Since Add(foo, 0) will not allow
# the 0 to pass, we use __add__ directly.
return l.__add__(0) == r.evalf().__add__(0)
return False
if check(lhs, rhs) or check(rhs, lhs):
return S.One
if any(i.is_Pow or i.is_Mul for i in (lhs, rhs)):
# gruntz and limit wants a literal I to not combine
# with a power of -1
d = Dummy('I')
_i = {S.ImaginaryUnit: d}
i_ = {d: S.ImaginaryUnit}
a = lhs.xreplace(_i).as_powers_dict()
b = rhs.xreplace(_i).as_powers_dict()
blen = len(b)
for bi in tuple(b.keys()):
if bi in a:
a[bi] -= b.pop(bi)
if not a[bi]:
a.pop(bi)
if len(b) != blen:
lhs = Mul(*[k**v for k, v in a.items()]).xreplace(i_)
rhs = Mul(*[k**v for k, v in b.items()]).xreplace(i_)
rv = lhs/rhs
srv = signsimp(rv)
return srv if srv.is_Number else rv
def as_powers_dict(self):
d = defaultdict(int)
for term in self.args:
for b, e in term.as_powers_dict().items():
d[b] += e
return d
def as_numer_denom(self):
# don't use _from_args to rebuild the numerators and denominators
# as the order is not guaranteed to be the same once they have
# been separated from each other
numers, denoms = list(zip(*[f.as_numer_denom() for f in self.args]))
return self.func(*numers), self.func(*denoms)
def as_base_exp(self):
e1 = None
bases = []
nc = 0
for m in self.args:
b, e = m.as_base_exp()
if not b.is_commutative:
nc += 1
if e1 is None:
e1 = e
elif e != e1 or nc > 1:
return self, S.One
bases.append(b)
return self.func(*bases), e1
def _eval_is_polynomial(self, syms):
return all(term._eval_is_polynomial(syms) for term in self.args)
def _eval_is_rational_function(self, syms):
return all(term._eval_is_rational_function(syms) for term in self.args)
def _eval_is_meromorphic(self, x, a):
return _fuzzy_group((arg.is_meromorphic(x, a) for arg in self.args),
quick_exit=True)
def _eval_is_algebraic_expr(self, syms):
return all(term._eval_is_algebraic_expr(syms) for term in self.args)
_eval_is_commutative = lambda self: _fuzzy_group(
a.is_commutative for a in self.args)
def _eval_is_complex(self):
comp = _fuzzy_group(a.is_complex for a in self.args)
if comp is False:
if any(a.is_infinite for a in self.args):
if any(a.is_zero is not False for a in self.args):
return None
return False
return comp
def _eval_is_zero_infinite_helper(self):
#
# Helper used by _eval_is_zero and _eval_is_infinite.
#
# Three-valued logic is tricky so let us reason this carefully. It
# would be nice to say that we just check is_zero/is_infinite in all
# args but we need to be careful about the case that one arg is zero
# and another is infinite like Mul(0, oo) or more importantly a case
# where it is not known if the arguments are zero or infinite like
# Mul(y, 1/x). If either y or x could be zero then there is a
# *possibility* that we have Mul(0, oo) which should give None for both
# is_zero and is_infinite.
#
# We keep track of whether we have seen a zero or infinity but we also
# need to keep track of whether we have *possibly* seen one which
# would be indicated by None.
#
# For each argument there is the possibility that is_zero might give
# True, False or None and likewise that is_infinite might give True,
# False or None, giving 9 combinations. The True cases for is_zero and
# is_infinite are mutually exclusive though so there are 3 main cases:
#
# - is_zero = True
# - is_infinite = True
# - is_zero and is_infinite are both either False or None
#
# At the end seen_zero and seen_infinite can be any of 9 combinations
# of True/False/None. Unless one is False though we cannot return
# anything except None:
#
# - is_zero=True needs seen_zero=True and seen_infinite=False
# - is_zero=False needs seen_zero=False
# - is_infinite=True needs seen_infinite=True and seen_zero=False
# - is_infinite=False needs seen_infinite=False
# - anything else gives both is_zero=None and is_infinite=None
#
# The loop only sets the flags to True or None and never back to False.
# Hence as soon as neither flag is False we exit early returning None.
# In particular as soon as we encounter a single arg that has
# is_zero=is_infinite=None we exit. This is a common case since it is
# the default assumptions for a Symbol and also the case for most
# expressions containing such a symbol. The early exit gives a big
# speedup for something like Mul(*symbols('x:1000')).is_zero.
#
seen_zero = seen_infinite = False
for a in self.args:
if a.is_zero:
if seen_infinite is not False:
return None, None
seen_zero = True
elif a.is_infinite:
if seen_zero is not False:
return None, None
seen_infinite = True
else:
if seen_zero is False and a.is_zero is None:
if seen_infinite is not False:
return None, None
seen_zero = None
if seen_infinite is False and a.is_infinite is None:
if seen_zero is not False:
return None, None
seen_infinite = None
return seen_zero, seen_infinite
def _eval_is_zero(self):
# True iff any arg is zero and no arg is infinite but need to handle
# three valued logic carefully.
seen_zero, seen_infinite = self._eval_is_zero_infinite_helper()
if seen_zero is False:
return False
elif seen_zero is True and seen_infinite is False:
return True
else:
return None
def _eval_is_infinite(self):
# True iff any arg is infinite and no arg is zero but need to handle
# three valued logic carefully.
seen_zero, seen_infinite = self._eval_is_zero_infinite_helper()
if seen_infinite is True and seen_zero is False:
return True
elif seen_infinite is False:
return False
else:
return None
# We do not need to implement _eval_is_finite because the assumptions
# system can infer it from finite = not infinite.
def _eval_is_rational(self):
r = _fuzzy_group((a.is_rational for a in self.args), quick_exit=True)
if r:
return r
elif r is False:
# All args except one are rational
if all(a.is_zero is False for a in self.args):
return False
def _eval_is_algebraic(self):
r = _fuzzy_group((a.is_algebraic for a in self.args), quick_exit=True)
if r:
return r
elif r is False:
# All args except one are algebraic
if all(a.is_zero is False for a in self.args):
return False
# without involving odd/even checks this code would suffice:
#_eval_is_integer = lambda self: _fuzzy_group(
# (a.is_integer for a in self.args), quick_exit=True)
def _eval_is_integer(self):
is_rational = self._eval_is_rational()
if is_rational is False:
return False
numerators = []
denominators = []
unknown = False
for a in self.args:
hit = False
if a.is_integer:
if abs(a) is not S.One:
numerators.append(a)
elif a.is_Rational:
n, d = a.as_numer_denom()
if abs(n) is not S.One:
numerators.append(n)
if d is not S.One:
denominators.append(d)
elif a.is_Pow:
b, e = a.as_base_exp()
if not b.is_integer or not e.is_integer:
hit = unknown = True
if e.is_negative:
denominators.append(2 if a is S.Half else
Pow(a, S.NegativeOne))
elif not hit:
# int b and pos int e: a = b**e is integer
assert not e.is_positive
# for rational self and e equal to zero: a = b**e is 1
assert not e.is_zero
return # sign of e unknown -> self.is_integer unknown
else:
# x**2, 2**x, or x**y with x and y int-unknown -> unknown
return
else:
return
if not denominators and not unknown:
return True
allodd = lambda x: all(i.is_odd for i in x)
alleven = lambda x: all(i.is_even for i in x)
anyeven = lambda x: any(i.is_even for i in x)
from .relational import is_gt
if not numerators and denominators and all(
is_gt(_, S.One) for _ in denominators):
return False
elif unknown:
return
elif allodd(numerators) and anyeven(denominators):
return False
elif anyeven(numerators) and denominators == [2]:
return True
elif alleven(numerators) and allodd(denominators
) and (Mul(*denominators, evaluate=False) - 1
).is_positive:
return False
if len(denominators) == 1:
d = denominators[0]
if d.is_Integer and d.is_even:
# if minimal power of 2 in num vs den is not
# negative then we have an integer
if (Add(*[i.as_base_exp()[1] for i in
numerators if i.is_even]) - trailing(d.p)
).is_nonnegative:
return True
if len(numerators) == 1:
n = numerators[0]
if n.is_Integer and n.is_even:
# if minimal power of 2 in den vs num is positive
# then we have have a non-integer
if (Add(*[i.as_base_exp()[1] for i in
denominators if i.is_even]) - trailing(n.p)
).is_positive:
return False
def _eval_is_polar(self):
has_polar = any(arg.is_polar for arg in self.args)
return has_polar and \
all(arg.is_polar or arg.is_positive for arg in self.args)
def _eval_is_extended_real(self):
return self._eval_real_imag(True)
def _eval_real_imag(self, real):
zero = False
t_not_re_im = None
for t in self.args:
if (t.is_complex or t.is_infinite) is False and t.is_extended_real is False:
return False
elif t.is_imaginary: # I
real = not real
elif t.is_extended_real: # 2
if not zero:
z = t.is_zero
if not z and zero is False:
zero = z
elif z:
if all(a.is_finite for a in self.args):
return True
return
elif t.is_extended_real is False:
# symbolic or literal like `2 + I` or symbolic imaginary
if t_not_re_im:
return # complex terms might cancel
t_not_re_im = t
elif t.is_imaginary is False: # symbolic like `2` or `2 + I`
if t_not_re_im:
return # complex terms might cancel
t_not_re_im = t
else:
return
if t_not_re_im:
if t_not_re_im.is_extended_real is False:
if real: # like 3
return zero # 3*(smthng like 2 + I or i) is not real
if t_not_re_im.is_imaginary is False: # symbolic 2 or 2 + I
if not real: # like I
return zero # I*(smthng like 2 or 2 + I) is not real
elif zero is False:
return real # can't be trumped by 0
elif real:
return real # doesn't matter what zero is
def _eval_is_imaginary(self):
if all(a.is_zero is False and a.is_finite for a in self.args):
return self._eval_real_imag(False)
def _eval_is_hermitian(self):
return self._eval_herm_antiherm(True)
def _eval_is_antihermitian(self):
return self._eval_herm_antiherm(False)
def _eval_herm_antiherm(self, herm):
for t in self.args:
if t.is_hermitian is None or t.is_antihermitian is None:
return
if t.is_hermitian:
continue
elif t.is_antihermitian:
herm = not herm
else:
return
if herm is not False:
return herm
is_zero = self._eval_is_zero()
if is_zero:
return True
elif is_zero is False:
return herm
def _eval_is_irrational(self):
for t in self.args:
a = t.is_irrational
if a:
others = list(self.args)
others.remove(t)
if all((x.is_rational and fuzzy_not(x.is_zero)) is True for x in others):
return True
return
if a is None:
return
if all(x.is_real for x in self.args):
return False
def _eval_is_extended_positive(self):
"""Return True if self is positive, False if not, and None if it
cannot be determined.
Explanation
===========
This algorithm is non-recursive and works by keeping track of the
sign which changes when a negative or nonpositive is encountered.
Whether a nonpositive or nonnegative is seen is also tracked since
the presence of these makes it impossible to return True, but
possible to return False if the end result is nonpositive. e.g.
pos * neg * nonpositive -> pos or zero -> None is returned
pos * neg * nonnegative -> neg or zero -> False is returned
"""
return self._eval_pos_neg(1)
def _eval_pos_neg(self, sign):
saw_NON = saw_NOT = False
for t in self.args:
if t.is_extended_positive:
continue
elif t.is_extended_negative:
sign = -sign
elif t.is_zero:
if all(a.is_finite for a in self.args):
return False
return
elif t.is_extended_nonpositive:
sign = -sign
saw_NON = True
elif t.is_extended_nonnegative:
saw_NON = True
# FIXME: is_positive/is_negative is False doesn't take account of
# Symbol('x', infinite=True, extended_real=True) which has
# e.g. is_positive is False but has uncertain sign.
elif t.is_positive is False:
sign = -sign
if saw_NOT:
return
saw_NOT = True
elif t.is_negative is False:
if saw_NOT:
return
saw_NOT = True
else:
return
if sign == 1 and saw_NON is False and saw_NOT is False:
return True
if sign < 0:
return False
def _eval_is_extended_negative(self):
return self._eval_pos_neg(-1)
def _eval_is_odd(self):
is_integer = self._eval_is_integer()
if is_integer is not True:
return is_integer
from sympy.simplify.radsimp import fraction
n, d = fraction(self)
if d.is_Integer and d.is_even:
# if minimal power of 2 in num vs den is
# positive then we have an even number
if (Add(*[i.as_base_exp()[1] for i in
Mul.make_args(n) if i.is_even]) - trailing(d.p)
).is_positive:
return False
return
r, acc = True, 1
for t in self.args:
if abs(t) is S.One:
continue
if t.is_even:
return False
if r is False:
pass
elif acc != 1 and (acc + t).is_odd:
r = False
elif t.is_even is None:
r = None
acc = t
return r
def _eval_is_even(self):
from sympy.simplify.radsimp import fraction
n, d = fraction(self)
if n.is_Integer and n.is_even:
# if minimal power of 2 in den vs num is not
# negative then this is not an integer and
# can't be even
if (Add(*[i.as_base_exp()[1] for i in
Mul.make_args(d) if i.is_even]) - trailing(n.p)
).is_nonnegative:
return False
def _eval_is_composite(self):
"""
Here we count the number of arguments that have a minimum value
greater than two.
If there are more than one of such a symbol then the result is composite.
Else, the result cannot be determined.
"""
number_of_args = 0 # count of symbols with minimum value greater than one
for arg in self.args:
if not (arg.is_integer and arg.is_positive):
return None
if (arg-1).is_positive:
number_of_args += 1
if number_of_args > 1:
return True
def _eval_subs(self, old, new):
from sympy.functions.elementary.complexes import sign
from sympy.ntheory.factor_ import multiplicity
from sympy.simplify.powsimp import powdenest
from sympy.simplify.radsimp import fraction
if not old.is_Mul:
return None
# try keep replacement literal so -2*x doesn't replace 4*x
if old.args[0].is_Number and old.args[0] < 0:
if self.args[0].is_Number:
if self.args[0] < 0:
return self._subs(-old, -new)
return None
def base_exp(a):
# if I and -1 are in a Mul, they get both end up with
# a -1 base (see issue 6421); all we want here are the
# true Pow or exp separated into base and exponent
from sympy.functions.elementary.exponential import exp
if a.is_Pow or isinstance(a, exp):
return a.as_base_exp()
return a, S.One
def breakup(eq):
"""break up powers of eq when treated as a Mul:
b**(Rational*e) -> b**e, Rational
commutatives come back as a dictionary {b**e: Rational}
noncommutatives come back as a list [(b**e, Rational)]
"""
(c, nc) = (defaultdict(int), [])
for a in Mul.make_args(eq):
a = powdenest(a)
(b, e) = base_exp(a)
if e is not S.One:
(co, _) = e.as_coeff_mul()
b = Pow(b, e/co)
e = co
if a.is_commutative:
c[b] += e
else:
nc.append([b, e])
return (c, nc)
def rejoin(b, co):
"""
Put rational back with exponent; in general this is not ok, but
since we took it from the exponent for analysis, it's ok to put
it back.
"""
(b, e) = base_exp(b)
return Pow(b, e*co)
def ndiv(a, b):
"""if b divides a in an extractive way (like 1/4 divides 1/2
but not vice versa, and 2/5 does not divide 1/3) then return
the integer number of times it divides, else return 0.
"""
if not b.q % a.q or not a.q % b.q:
return int(a/b)
return 0
# give Muls in the denominator a chance to be changed (see issue 5651)
# rv will be the default return value
rv = None
n, d = fraction(self)
self2 = self
if d is not S.One:
self2 = n._subs(old, new)/d._subs(old, new)
if not self2.is_Mul:
return self2._subs(old, new)
if self2 != self:
rv = self2
# Now continue with regular substitution.
# handle the leading coefficient and use it to decide if anything
# should even be started; we always know where to find the Rational
# so it's a quick test
co_self = self2.args[0]
co_old = old.args[0]
co_xmul = None
if co_old.is_Rational and co_self.is_Rational:
# if coeffs are the same there will be no updating to do
# below after breakup() step; so skip (and keep co_xmul=None)
if co_old != co_self:
co_xmul = co_self.extract_multiplicatively(co_old)
elif co_old.is_Rational:
return rv
# break self and old into factors
(c, nc) = breakup(self2)
(old_c, old_nc) = breakup(old)
# update the coefficients if we had an extraction
# e.g. if co_self were 2*(3/35*x)**2 and co_old = 3/5
# then co_self in c is replaced by (3/5)**2 and co_residual
# is 2*(1/7)**2
if co_xmul and co_xmul.is_Rational and abs(co_old) != 1:
mult = S(multiplicity(abs(co_old), co_self))
c.pop(co_self)
if co_old in c:
c[co_old] += mult
else:
c[co_old] = mult
co_residual = co_self/co_old**mult
else:
co_residual = 1
# do quick tests to see if we can't succeed
ok = True
if len(old_nc) > len(nc):
# more non-commutative terms
ok = False
elif len(old_c) > len(c):
# more commutative terms
ok = False
elif {i[0] for i in old_nc}.difference({i[0] for i in nc}):
# unmatched non-commutative bases
ok = False
elif set(old_c).difference(set(c)):
# unmatched commutative terms
ok = False
elif any(sign(c[b]) != sign(old_c[b]) for b in old_c):
# differences in sign
ok = False
if not ok:
return rv
if not old_c:
cdid = None
else:
rat = []
for (b, old_e) in old_c.items():
c_e = c[b]
rat.append(ndiv(c_e, old_e))
if not rat[-1]:
return rv
cdid = min(rat)
if not old_nc:
ncdid = None
for i in range(len(nc)):
nc[i] = rejoin(*nc[i])
else:
ncdid = 0 # number of nc replacements we did
take = len(old_nc) # how much to look at each time
limit = cdid or S.Infinity # max number that we can take
failed = [] # failed terms will need subs if other terms pass
i = 0
while limit and i + take <= len(nc):
hit = False
# the bases must be equivalent in succession, and
# the powers must be extractively compatible on the
# first and last factor but equal in between.
rat = []
for j in range(take):
if nc[i + j][0] != old_nc[j][0]:
break
elif j == 0:
rat.append(ndiv(nc[i + j][1], old_nc[j][1]))
elif j == take - 1:
rat.append(ndiv(nc[i + j][1], old_nc[j][1]))
elif nc[i + j][1] != old_nc[j][1]:
break
else:
rat.append(1)
j += 1
else:
ndo = min(rat)
if ndo:
if take == 1:
if cdid:
ndo = min(cdid, ndo)
nc[i] = Pow(new, ndo)*rejoin(nc[i][0],
nc[i][1] - ndo*old_nc[0][1])
else:
ndo = 1
# the left residual
l = rejoin(nc[i][0], nc[i][1] - ndo*
old_nc[0][1])
# eliminate all middle terms
mid = new
# the right residual (which may be the same as the middle if take == 2)
ir = i + take - 1
r = (nc[ir][0], nc[ir][1] - ndo*
old_nc[-1][1])
if r[1]:
if i + take < len(nc):
nc[i:i + take] = [l*mid, r]
else:
r = rejoin(*r)
nc[i:i + take] = [l*mid*r]
else:
# there was nothing left on the right
nc[i:i + take] = [l*mid]
limit -= ndo
ncdid += ndo
hit = True
if not hit:
# do the subs on this failing factor
failed.append(i)
i += 1
else:
if not ncdid:
return rv
# although we didn't fail, certain nc terms may have
# failed so we rebuild them after attempting a partial
# subs on them
failed.extend(range(i, len(nc)))
for i in failed:
nc[i] = rejoin(*nc[i]).subs(old, new)
# rebuild the expression
if cdid is None:
do = ncdid
elif ncdid is None:
do = cdid
else:
do = min(ncdid, cdid)
margs = []
for b in c:
if b in old_c:
# calculate the new exponent
e = c[b] - old_c[b]*do
margs.append(rejoin(b, e))
else:
margs.append(rejoin(b.subs(old, new), c[b]))
if cdid and not ncdid:
# in case we are replacing commutative with non-commutative,
# we want the new term to come at the front just like the
# rest of this routine
margs = [Pow(new, cdid)] + margs
return co_residual*self2.func(*margs)*self2.func(*nc)
def _eval_nseries(self, x, n, logx, cdir=0):
from .function import PoleError
from sympy.functions.elementary.integers import ceiling
from sympy.series.order import Order
def coeff_exp(term, x):
lt = term.as_coeff_exponent(x)
if lt[0].has(x):
try:
lt = term.leadterm(x)
except ValueError:
return term, S.Zero
return lt
ords = []
try:
for t in self.args:
coeff, exp = t.leadterm(x)
if not coeff.has(x):
ords.append((t, exp))
else:
raise ValueError
n0 = sum(t[1] for t in ords if t[1].is_number)
facs = []
for t, m in ords:
n1 = ceiling(n - n0 + (m if m.is_number else 0))
s = t.nseries(x, n=n1, logx=logx, cdir=cdir)
ns = s.getn()
if ns is not None:
if ns < n1: # less than expected
n -= n1 - ns # reduce n
facs.append(s)
except (ValueError, NotImplementedError, TypeError, PoleError):
# XXX: Catching so many generic exceptions around a large block of
# code will mask bugs. Whatever purpose catching these exceptions
# serves should be handled in a different way.
n0 = sympify(sum(t[1] for t in ords if t[1].is_number))
if n0.is_nonnegative:
n0 = S.Zero
facs = [t.nseries(x, n=ceiling(n-n0), logx=logx, cdir=cdir) for t in self.args]
from sympy.simplify.powsimp import powsimp
res = powsimp(self.func(*facs).expand(), combine='exp', deep=True)
if res.has(Order):
res += Order(x**n, x)
return res
res = S.Zero
ords2 = [Add.make_args(factor) for factor in facs]
for fac in product(*ords2):
ords3 = [coeff_exp(term, x) for term in fac]
coeffs, powers = zip(*ords3)
power = sum(powers)
if (power - n).is_negative:
res += Mul(*coeffs)*(x**power)
def max_degree(e, x):
if e is x:
return S.One
if e.is_Atom:
return S.Zero
if e.is_Add:
return max(max_degree(a, x) for a in e.args)
if e.is_Mul:
return Add(*[max_degree(a, x) for a in e.args])
if e.is_Pow:
return max_degree(e.base, x)*e.exp
return S.Zero
if self.is_polynomial(x):
from sympy.polys.polyerrors import PolynomialError
from sympy.polys.polytools import degree
try:
if max_degree(self, x) >= n or degree(self, x) != degree(res, x):
res += Order(x**n, x)
except PolynomialError:
pass
else:
return res
if res != self:
if (self - res).subs(x, 0) == S.Zero and n > 0:
lt = self._eval_as_leading_term(x, logx=logx, cdir=cdir)
if lt == S.Zero:
return res
res += Order(x**n, x)
return res
def _eval_as_leading_term(self, x, logx=None, cdir=0):
return self.func(*[t.as_leading_term(x, logx=logx, cdir=cdir) for t in self.args])
def _eval_conjugate(self):
return self.func(*[t.conjugate() for t in self.args])
def _eval_transpose(self):
return self.func(*[t.transpose() for t in self.args[::-1]])
def _eval_adjoint(self):
return self.func(*[t.adjoint() for t in self.args[::-1]])
def as_content_primitive(self, radical=False, clear=True):
"""Return the tuple (R, self/R) where R is the positive Rational
extracted from self.
Examples
========
>>> from sympy import sqrt
>>> (-3*sqrt(2)*(2 - 2*sqrt(2))).as_content_primitive()
(6, -sqrt(2)*(1 - sqrt(2)))
See docstring of Expr.as_content_primitive for more examples.
"""
coef = S.One
args = []
for a in self.args:
c, p = a.as_content_primitive(radical=radical, clear=clear)
coef *= c
if p is not S.One:
args.append(p)
# don't use self._from_args here to reconstruct args
# since there may be identical args now that should be combined
# e.g. (2+2*x)*(3+3*x) should be (6, (1 + x)**2) not (6, (1+x)*(1+x))
return coef, self.func(*args)
def as_ordered_factors(self, order=None):
"""Transform an expression into an ordered list of factors.
Examples
========
>>> from sympy import sin, cos
>>> from sympy.abc import x, y
>>> (2*x*y*sin(x)*cos(x)).as_ordered_factors()
[2, x, y, sin(x), cos(x)]
"""
cpart, ncpart = self.args_cnc()
cpart.sort(key=lambda expr: expr.sort_key(order=order))
return cpart + ncpart
@property
def _sorted_args(self):
return tuple(self.as_ordered_factors())
mul = AssocOpDispatcher('mul')
def prod(a, start=1):
"""Return product of elements of a. Start with int 1 so if only
ints are included then an int result is returned.
Examples
========
>>> from sympy import prod, S
>>> prod(range(3))
0
>>> type(_) is int
True
>>> prod([S(2), 3])
6
>>> _.is_Integer
True
You can start the product at something other than 1:
>>> prod([1, 2], 3)
6
"""
return reduce(operator.mul, a, start)
def _keep_coeff(coeff, factors, clear=True, sign=False):
"""Return ``coeff*factors`` unevaluated if necessary.
If ``clear`` is False, do not keep the coefficient as a factor
if it can be distributed on a single factor such that one or
more terms will still have integer coefficients.
If ``sign`` is True, allow a coefficient of -1 to remain factored out.
Examples
========
>>> from sympy.core.mul import _keep_coeff
>>> from sympy.abc import x, y
>>> from sympy import S
>>> _keep_coeff(S.Half, x + 2)
(x + 2)/2
>>> _keep_coeff(S.Half, x + 2, clear=False)
x/2 + 1
>>> _keep_coeff(S.Half, (x + 2)*y, clear=False)
y*(x + 2)/2
>>> _keep_coeff(S(-1), x + y)
-x - y
>>> _keep_coeff(S(-1), x + y, sign=True)
-(x + y)
"""
if not coeff.is_Number:
if factors.is_Number:
factors, coeff = coeff, factors
else:
return coeff*factors
if factors is S.One:
return coeff
if coeff is S.One:
return factors
elif coeff is S.NegativeOne and not sign:
return -factors
elif factors.is_Add:
if not clear and coeff.is_Rational and coeff.q != 1:
args = [i.as_coeff_Mul() for i in factors.args]
args = [(_keep_coeff(c, coeff), m) for c, m in args]
if any(c.is_Integer for c, _ in args):
return Add._from_args([Mul._from_args(
i[1:] if i[0] == 1 else i) for i in args])
return Mul(coeff, factors, evaluate=False)
elif factors.is_Mul:
margs = list(factors.args)
if margs[0].is_Number:
margs[0] *= coeff
if margs[0] == 1:
margs.pop(0)
else:
margs.insert(0, coeff)
return Mul._from_args(margs)
else:
m = coeff*factors
if m.is_Number and not factors.is_Number:
m = Mul._from_args((coeff, factors))
return m
def expand_2arg(e):
def do(e):
if e.is_Mul:
c, r = e.as_coeff_Mul()
if c.is_Number and r.is_Add:
return _unevaluated_Add(*[c*ri for ri in r.args])
return e
return bottom_up(e, do)
from .numbers import Rational
from .power import Pow
from .add import Add, _unevaluated_Add
PK ]ZZZux�#� � sympy/core/multidimensional.py"""
Provides functionality for multidimensional usage of scalar-functions.
Read the vectorize docstring for more details.
"""
from functools import wraps
def apply_on_element(f, args, kwargs, n):
"""
Returns a structure with the same dimension as the specified argument,
where each basic element is replaced by the function f applied on it. All
other arguments stay the same.
"""
# Get the specified argument.
if isinstance(n, int):
structure = args[n]
is_arg = True
elif isinstance(n, str):
structure = kwargs[n]
is_arg = False
# Define reduced function that is only dependent on the specified argument.
def f_reduced(x):
if hasattr(x, "__iter__"):
return list(map(f_reduced, x))
else:
if is_arg:
args[n] = x
else:
kwargs[n] = x
return f(*args, **kwargs)
# f_reduced will call itself recursively so that in the end f is applied to
# all basic elements.
return list(map(f_reduced, structure))
def iter_copy(structure):
"""
Returns a copy of an iterable object (also copying all embedded iterables).
"""
return [iter_copy(i) if hasattr(i, "__iter__") else i for i in structure]
def structure_copy(structure):
"""
Returns a copy of the given structure (numpy-array, list, iterable, ..).
"""
if hasattr(structure, "copy"):
return structure.copy()
return iter_copy(structure)
class vectorize:
"""
Generalizes a function taking scalars to accept multidimensional arguments.
Examples
========
>>> from sympy import vectorize, diff, sin, symbols, Function
>>> x, y, z = symbols('x y z')
>>> f, g, h = list(map(Function, 'fgh'))
>>> @vectorize(0)
... def vsin(x):
... return sin(x)
>>> vsin([1, x, y])
[sin(1), sin(x), sin(y)]
>>> @vectorize(0, 1)
... def vdiff(f, y):
... return diff(f, y)
>>> vdiff([f(x, y, z), g(x, y, z), h(x, y, z)], [x, y, z])
[[Derivative(f(x, y, z), x), Derivative(f(x, y, z), y), Derivative(f(x, y, z), z)], [Derivative(g(x, y, z), x), Derivative(g(x, y, z), y), Derivative(g(x, y, z), z)], [Derivative(h(x, y, z), x), Derivative(h(x, y, z), y), Derivative(h(x, y, z), z)]]
"""
def __init__(self, *mdargs):
"""
The given numbers and strings characterize the arguments that will be
treated as data structures, where the decorated function will be applied
to every single element.
If no argument is given, everything is treated multidimensional.
"""
for a in mdargs:
if not isinstance(a, (int, str)):
raise TypeError("a is of invalid type")
self.mdargs = mdargs
def __call__(self, f):
"""
Returns a wrapper for the one-dimensional function that can handle
multidimensional arguments.
"""
@wraps(f)
def wrapper(*args, **kwargs):
# Get arguments that should be treated multidimensional
if self.mdargs:
mdargs = self.mdargs
else:
mdargs = range(len(args)) + kwargs.keys()
arglength = len(args)
for n in mdargs:
if isinstance(n, int):
if n >= arglength:
continue
entry = args[n]
is_arg = True
elif isinstance(n, str):
try:
entry = kwargs[n]
except KeyError:
continue
is_arg = False
if hasattr(entry, "__iter__"):
# Create now a copy of the given array and manipulate then
# the entries directly.
if is_arg:
args = list(args)
args[n] = structure_copy(entry)
else:
kwargs[n] = structure_copy(entry)
result = apply_on_element(wrapper, args, kwargs, n)
return result
return f(*args, **kwargs)
return wrapper
PK ]ZZZ�H0� sympy/core/numbers.pyfrom __future__ import annotations
import numbers
import decimal
import fractions
import math
from .containers import Tuple
from .sympify import (SympifyError, _sympy_converter, sympify, _convert_numpy_types,
_sympify, _is_numpy_instance)
from .singleton import S, Singleton
from .basic import Basic
from .expr import Expr, AtomicExpr
from .evalf import pure_complex
from .cache import cacheit, clear_cache
from .decorators import _sympifyit
from .intfunc import num_digits, igcd, ilcm, mod_inverse, integer_nthroot
from .logic import fuzzy_not
from .kind import NumberKind
from sympy.external.gmpy import SYMPY_INTS, gmpy, flint
from sympy.multipledispatch import dispatch
import mpmath
import mpmath.libmp as mlib
from mpmath.libmp import bitcount, round_nearest as rnd
from mpmath.libmp.backend import MPZ
from mpmath.libmp import mpf_pow, mpf_pi, mpf_e, phi_fixed
from mpmath.ctx_mp_python import mpnumeric
from mpmath.libmp.libmpf import (
finf as _mpf_inf, fninf as _mpf_ninf,
fnan as _mpf_nan, fzero, _normalize as mpf_normalize,
prec_to_dps, dps_to_prec)
from sympy.utilities.misc import debug
from .parameters import global_parameters
_LOG2 = math.log(2)
def comp(z1, z2, tol=None):
r"""Return a bool indicating whether the error between z1 and z2
is $\le$ ``tol``.
Examples
========
If ``tol`` is ``None`` then ``True`` will be returned if
:math:`|z1 - z2|\times 10^p \le 5` where $p$ is minimum value of the
decimal precision of each value.
>>> from sympy import comp, pi
>>> pi4 = pi.n(4); pi4
3.142
>>> comp(_, 3.142)
True
>>> comp(pi4, 3.141)
False
>>> comp(pi4, 3.143)
False
A comparison of strings will be made
if ``z1`` is a Number and ``z2`` is a string or ``tol`` is ''.
>>> comp(pi4, 3.1415)
True
>>> comp(pi4, 3.1415, '')
False
When ``tol`` is provided and $z2$ is non-zero and
:math:`|z1| > 1` the error is normalized by :math:`|z1|`:
>>> abs(pi4 - 3.14)/pi4
0.000509791731426756
>>> comp(pi4, 3.14, .001) # difference less than 0.1%
True
>>> comp(pi4, 3.14, .0005) # difference less than 0.1%
False
When :math:`|z1| \le 1` the absolute error is used:
>>> 1/pi4
0.3183
>>> abs(1/pi4 - 0.3183)/(1/pi4)
3.07371499106316e-5
>>> abs(1/pi4 - 0.3183)
9.78393554684764e-6
>>> comp(1/pi4, 0.3183, 1e-5)
True
To see if the absolute error between ``z1`` and ``z2`` is less
than or equal to ``tol``, call this as ``comp(z1 - z2, 0, tol)``
or ``comp(z1 - z2, tol=tol)``:
>>> abs(pi4 - 3.14)
0.00160156249999988
>>> comp(pi4 - 3.14, 0, .002)
True
>>> comp(pi4 - 3.14, 0, .001)
False
"""
if isinstance(z2, str):
if not pure_complex(z1, or_real=True):
raise ValueError('when z2 is a str z1 must be a Number')
return str(z1) == z2
if not z1:
z1, z2 = z2, z1
if not z1:
return True
if not tol:
a, b = z1, z2
if tol == '':
return str(a) == str(b)
if tol is None:
a, b = sympify(a), sympify(b)
if not all(i.is_number for i in (a, b)):
raise ValueError('expecting 2 numbers')
fa = a.atoms(Float)
fb = b.atoms(Float)
if not fa and not fb:
# no floats -- compare exactly
return a == b
# get a to be pure_complex
for _ in range(2):
ca = pure_complex(a, or_real=True)
if not ca:
if fa:
a = a.n(prec_to_dps(min(i._prec for i in fa)))
ca = pure_complex(a, or_real=True)
break
else:
fa, fb = fb, fa
a, b = b, a
cb = pure_complex(b)
if not cb and fb:
b = b.n(prec_to_dps(min(i._prec for i in fb)))
cb = pure_complex(b, or_real=True)
if ca and cb and (ca[1] or cb[1]):
return all(comp(i, j) for i, j in zip(ca, cb))
tol = 10**prec_to_dps(min(a._prec, getattr(b, '_prec', a._prec)))
return int(abs(a - b)*tol) <= 5
diff = abs(z1 - z2)
az1 = abs(z1)
if z2 and az1 > 1:
return diff/az1 <= tol
else:
return diff <= tol
def mpf_norm(mpf, prec):
"""Return the mpf tuple normalized appropriately for the indicated
precision after doing a check to see if zero should be returned or
not when the mantissa is 0. ``mpf_normlize`` always assumes that this
is zero, but it may not be since the mantissa for mpf's values "+inf",
"-inf" and "nan" have a mantissa of zero, too.
Note: this is not intended to validate a given mpf tuple, so sending
mpf tuples that were not created by mpmath may produce bad results. This
is only a wrapper to ``mpf_normalize`` which provides the check for non-
zero mpfs that have a 0 for the mantissa.
"""
sign, man, expt, bc = mpf
if not man:
# hack for mpf_normalize which does not do this;
# it assumes that if man is zero the result is 0
# (see issue 6639)
if not bc:
return fzero
else:
# don't change anything; this should already
# be a well formed mpf tuple
return mpf
# Necessary if mpmath is using the gmpy backend
from mpmath.libmp.backend import MPZ
rv = mpf_normalize(sign, MPZ(man), expt, bc, prec, rnd)
return rv
# TODO: we should use the warnings module
_errdict = {"divide": False}
def seterr(divide=False):
"""
Should SymPy raise an exception on 0/0 or return a nan?
divide == True .... raise an exception
divide == False ... return nan
"""
if _errdict["divide"] != divide:
clear_cache()
_errdict["divide"] = divide
def _as_integer_ratio(p):
neg_pow, man, expt, _ = getattr(p, '_mpf_', mpmath.mpf(p)._mpf_)
p = [1, -1][neg_pow % 2]*man
if expt < 0:
q = 2**-expt
else:
q = 1
p *= 2**expt
return int(p), int(q)
def _decimal_to_Rational_prec(dec):
"""Convert an ordinary decimal instance to a Rational."""
if not dec.is_finite():
raise TypeError("dec must be finite, got %s." % dec)
s, d, e = dec.as_tuple()
prec = len(d)
if e >= 0: # it's an integer
rv = Integer(int(dec))
else:
s = (-1)**s
d = sum(di*10**i for i, di in enumerate(reversed(d)))
rv = Rational(s*d, 10**-e)
return rv, prec
_dig = str.maketrans(dict.fromkeys('1234567890'))
def _literal_float(s):
"""return True if s is space-trimmed number literal else False
Python allows underscore as digit separators: there must be a
digit on each side. So neither a leading underscore nor a
double underscore are valid as part of a number. A number does
not have to precede the decimal point, but there must be a
digit before the optional "e" or "E" that begins the signs
exponent of the number which must be an integer, perhaps with
underscore separators.
SymPy allows space as a separator; if the calling routine replaces
them with underscores then the same semantics will be enforced
for them as for underscores: there can only be 1 *between* digits.
We don't check for error from float(s) because we don't know
whether s is malicious or not. A regex for this could maybe
be written but will it be understood by most who read it?
"""
# mantissa and exponent
parts = s.split('e')
if len(parts) > 2:
return False
if len(parts) == 2:
m, e = parts
if e.startswith(tuple('+-')):
e = e[1:]
if not e:
return False
else:
m, e = s, '1'
# integer and fraction of mantissa
parts = m.split('.')
if len(parts) > 2:
return False
elif len(parts) == 2:
i, f = parts
else:
i, f = m, '1'
if not i and not f:
return False
if i and i[0] in '+-':
i = i[1:]
if not i: # -.3e4 -> -0.3e4
i = '1'
f = f or '1'
# check that all groups contain only digits and are not null
for n in (i, f, e):
for g in n.split('_'):
if not g or g.translate(_dig):
return False
return True
# (a,b) -> gcd(a,b)
# TODO caching with decorator, but not to degrade performance
class Number(AtomicExpr):
"""Represents atomic numbers in SymPy.
Explanation
===========
Floating point numbers are represented by the Float class.
Rational numbers (of any size) are represented by the Rational class.
Integer numbers (of any size) are represented by the Integer class.
Float and Rational are subclasses of Number; Integer is a subclass
of Rational.
For example, ``2/3`` is represented as ``Rational(2, 3)`` which is
a different object from the floating point number obtained with
Python division ``2/3``. Even for numbers that are exactly
represented in binary, there is a difference between how two forms,
such as ``Rational(1, 2)`` and ``Float(0.5)``, are used in SymPy.
The rational form is to be preferred in symbolic computations.
Other kinds of numbers, such as algebraic numbers ``sqrt(2)`` or
complex numbers ``3 + 4*I``, are not instances of Number class as
they are not atomic.
See Also
========
Float, Integer, Rational
"""
is_commutative = True
is_number = True
is_Number = True
__slots__ = ()
# Used to make max(x._prec, y._prec) return x._prec when only x is a float
_prec = -1
kind = NumberKind
def __new__(cls, *obj):
if len(obj) == 1:
obj = obj[0]
if isinstance(obj, Number):
return obj
if isinstance(obj, SYMPY_INTS):
return Integer(obj)
if isinstance(obj, tuple) and len(obj) == 2:
return Rational(*obj)
if isinstance(obj, (float, mpmath.mpf, decimal.Decimal)):
return Float(obj)
if isinstance(obj, str):
_obj = obj.lower() # float('INF') == float('inf')
if _obj == 'nan':
return S.NaN
elif _obj == 'inf':
return S.Infinity
elif _obj == '+inf':
return S.Infinity
elif _obj == '-inf':
return S.NegativeInfinity
val = sympify(obj)
if isinstance(val, Number):
return val
else:
raise ValueError('String "%s" does not denote a Number' % obj)
msg = "expected str|int|long|float|Decimal|Number object but got %r"
raise TypeError(msg % type(obj).__name__)
def could_extract_minus_sign(self):
return bool(self.is_extended_negative)
def invert(self, other, *gens, **args):
from sympy.polys.polytools import invert
if getattr(other, 'is_number', True):
return mod_inverse(self, other)
return invert(self, other, *gens, **args)
def __divmod__(self, other):
from sympy.functions.elementary.complexes import sign
try:
other = Number(other)
if self.is_infinite or S.NaN in (self, other):
return (S.NaN, S.NaN)
except TypeError:
return NotImplemented
if not other:
raise ZeroDivisionError('modulo by zero')
if self.is_Integer and other.is_Integer:
return Tuple(*divmod(self.p, other.p))
elif isinstance(other, Float):
rat = self/Rational(other)
else:
rat = self/other
if other.is_finite:
w = int(rat) if rat >= 0 else int(rat) - 1
r = self - other*w
if r == Float(other):
w += 1
r = 0
if isinstance(self, Float) or isinstance(other, Float):
r = Float(r) # in case w or r is 0
else:
w = 0 if not self or (sign(self) == sign(other)) else -1
r = other if w else self
return Tuple(w, r)
def __rdivmod__(self, other):
try:
other = Number(other)
except TypeError:
return NotImplemented
return divmod(other, self)
def _as_mpf_val(self, prec):
"""Evaluation of mpf tuple accurate to at least prec bits."""
raise NotImplementedError('%s needs ._as_mpf_val() method' %
(self.__class__.__name__))
def _eval_evalf(self, prec):
return Float._new(self._as_mpf_val(prec), prec)
def _as_mpf_op(self, prec):
prec = max(prec, self._prec)
return self._as_mpf_val(prec), prec
def __float__(self):
return mlib.to_float(self._as_mpf_val(53))
def floor(self):
raise NotImplementedError('%s needs .floor() method' %
(self.__class__.__name__))
def ceiling(self):
raise NotImplementedError('%s needs .ceiling() method' %
(self.__class__.__name__))
def __floor__(self):
return self.floor()
def __ceil__(self):
return self.ceiling()
def _eval_conjugate(self):
return self
def _eval_order(self, *symbols):
from sympy.series.order import Order
# Order(5, x, y) -> Order(1,x,y)
return Order(S.One, *symbols)
def _eval_subs(self, old, new):
if old == -self:
return -new
return self # there is no other possibility
@classmethod
def class_key(cls):
return 1, 0, 'Number'
@cacheit
def sort_key(self, order=None):
return self.class_key(), (0, ()), (), self
@_sympifyit('other', NotImplemented)
def __add__(self, other):
if isinstance(other, Number) and global_parameters.evaluate:
if other is S.NaN:
return S.NaN
elif other is S.Infinity:
return S.Infinity
elif other is S.NegativeInfinity:
return S.NegativeInfinity
return AtomicExpr.__add__(self, other)
@_sympifyit('other', NotImplemented)
def __sub__(self, other):
if isinstance(other, Number) and global_parameters.evaluate:
if other is S.NaN:
return S.NaN
elif other is S.Infinity:
return S.NegativeInfinity
elif other is S.NegativeInfinity:
return S.Infinity
return AtomicExpr.__sub__(self, other)
@_sympifyit('other', NotImplemented)
def __mul__(self, other):
if isinstance(other, Number) and global_parameters.evaluate:
if other is S.NaN:
return S.NaN
elif other is S.Infinity:
if self.is_zero:
return S.NaN
elif self.is_positive:
return S.Infinity
else:
return S.NegativeInfinity
elif other is S.NegativeInfinity:
if self.is_zero:
return S.NaN
elif self.is_positive:
return S.NegativeInfinity
else:
return S.Infinity
elif isinstance(other, Tuple):
return NotImplemented
return AtomicExpr.__mul__(self, other)
@_sympifyit('other', NotImplemented)
def __truediv__(self, other):
if isinstance(other, Number) and global_parameters.evaluate:
if other is S.NaN:
return S.NaN
elif other in (S.Infinity, S.NegativeInfinity):
return S.Zero
return AtomicExpr.__truediv__(self, other)
def __eq__(self, other):
raise NotImplementedError('%s needs .__eq__() method' %
(self.__class__.__name__))
def __ne__(self, other):
raise NotImplementedError('%s needs .__ne__() method' %
(self.__class__.__name__))
def __lt__(self, other):
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s < %s" % (self, other))
raise NotImplementedError('%s needs .__lt__() method' %
(self.__class__.__name__))
def __le__(self, other):
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s <= %s" % (self, other))
raise NotImplementedError('%s needs .__le__() method' %
(self.__class__.__name__))
def __gt__(self, other):
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s > %s" % (self, other))
return _sympify(other).__lt__(self)
def __ge__(self, other):
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s >= %s" % (self, other))
return _sympify(other).__le__(self)
def __hash__(self):
return super().__hash__()
def is_constant(self, *wrt, **flags):
return True
def as_coeff_mul(self, *deps, rational=True, **kwargs):
# a -> c*t
if self.is_Rational or not rational:
return self, ()
elif self.is_negative:
return S.NegativeOne, (-self,)
return S.One, (self,)
def as_coeff_add(self, *deps):
# a -> c + t
if self.is_Rational:
return self, ()
return S.Zero, (self,)
def as_coeff_Mul(self, rational=False):
"""Efficiently extract the coefficient of a product."""
if not rational:
return self, S.One
return S.One, self
def as_coeff_Add(self, rational=False):
"""Efficiently extract the coefficient of a summation."""
if not rational:
return self, S.Zero
return S.Zero, self
def gcd(self, other):
"""Compute GCD of `self` and `other`. """
from sympy.polys.polytools import gcd
return gcd(self, other)
def lcm(self, other):
"""Compute LCM of `self` and `other`. """
from sympy.polys.polytools import lcm
return lcm(self, other)
def cofactors(self, other):
"""Compute GCD and cofactors of `self` and `other`. """
from sympy.polys.polytools import cofactors
return cofactors(self, other)
class Float(Number):
"""Represent a floating-point number of arbitrary precision.
Examples
========
>>> from sympy import Float
>>> Float(3.5)
3.50000000000000
>>> Float(3)
3.00000000000000
Creating Floats from strings (and Python ``int`` and ``long``
types) will give a minimum precision of 15 digits, but the
precision will automatically increase to capture all digits
entered.
>>> Float(1)
1.00000000000000
>>> Float(10**20)
100000000000000000000.
>>> Float('1e20')
100000000000000000000.
However, *floating-point* numbers (Python ``float`` types) retain
only 15 digits of precision:
>>> Float(1e20)
1.00000000000000e+20
>>> Float(1.23456789123456789)
1.23456789123457
It may be preferable to enter high-precision decimal numbers
as strings:
>>> Float('1.23456789123456789')
1.23456789123456789
The desired number of digits can also be specified:
>>> Float('1e-3', 3)
0.00100
>>> Float(100, 4)
100.0
Float can automatically count significant figures if a null string
is sent for the precision; spaces or underscores are also allowed. (Auto-
counting is only allowed for strings, ints and longs).
>>> Float('123 456 789.123_456', '')
123456789.123456
>>> Float('12e-3', '')
0.012
>>> Float(3, '')
3.
If a number is written in scientific notation, only the digits before the
exponent are considered significant if a decimal appears, otherwise the
"e" signifies only how to move the decimal:
>>> Float('60.e2', '') # 2 digits significant
6.0e+3
>>> Float('60e2', '') # 4 digits significant
6000.
>>> Float('600e-2', '') # 3 digits significant
6.00
Notes
=====
Floats are inexact by their nature unless their value is a binary-exact
value.
>>> approx, exact = Float(.1, 1), Float(.125, 1)
For calculation purposes, evalf needs to be able to change the precision
but this will not increase the accuracy of the inexact value. The
following is the most accurate 5-digit approximation of a value of 0.1
that had only 1 digit of precision:
>>> approx.evalf(5)
0.099609
By contrast, 0.125 is exact in binary (as it is in base 10) and so it
can be passed to Float or evalf to obtain an arbitrary precision with
matching accuracy:
>>> Float(exact, 5)
0.12500
>>> exact.evalf(20)
0.12500000000000000000
Trying to make a high-precision Float from a float is not disallowed,
but one must keep in mind that the *underlying float* (not the apparent
decimal value) is being obtained with high precision. For example, 0.3
does not have a finite binary representation. The closest rational is
the fraction 5404319552844595/2**54. So if you try to obtain a Float of
0.3 to 20 digits of precision you will not see the same thing as 0.3
followed by 19 zeros:
>>> Float(0.3, 20)
0.29999999999999998890
If you want a 20-digit value of the decimal 0.3 (not the floating point
approximation of 0.3) you should send the 0.3 as a string. The underlying
representation is still binary but a higher precision than Python's float
is used:
>>> Float('0.3', 20)
0.30000000000000000000
Although you can increase the precision of an existing Float using Float
it will not increase the accuracy -- the underlying value is not changed:
>>> def show(f): # binary rep of Float
... from sympy import Mul, Pow
... s, m, e, b = f._mpf_
... v = Mul(int(m), Pow(2, int(e), evaluate=False), evaluate=False)
... print('%s at prec=%s' % (v, f._prec))
...
>>> t = Float('0.3', 3)
>>> show(t)
4915/2**14 at prec=13
>>> show(Float(t, 20)) # higher prec, not higher accuracy
4915/2**14 at prec=70
>>> show(Float(t, 2)) # lower prec
307/2**10 at prec=10
The same thing happens when evalf is used on a Float:
>>> show(t.evalf(20))
4915/2**14 at prec=70
>>> show(t.evalf(2))
307/2**10 at prec=10
Finally, Floats can be instantiated with an mpf tuple (n, c, p) to
produce the number (-1)**n*c*2**p:
>>> n, c, p = 1, 5, 0
>>> (-1)**n*c*2**p
-5
>>> Float((1, 5, 0))
-5.00000000000000
An actual mpf tuple also contains the number of bits in c as the last
element of the tuple:
>>> _._mpf_
(1, 5, 0, 3)
This is not needed for instantiation and is not the same thing as the
precision. The mpf tuple and the precision are two separate quantities
that Float tracks.
In SymPy, a Float is a number that can be computed with arbitrary
precision. Although floating point 'inf' and 'nan' are not such
numbers, Float can create these numbers:
>>> Float('-inf')
-oo
>>> _.is_Float
False
Zero in Float only has a single value. Values are not separate for
positive and negative zeroes.
"""
__slots__ = ('_mpf_', '_prec')
_mpf_: tuple[int, int, int, int]
# A Float, though rational in form, does not behave like
# a rational in all Python expressions so we deal with
# exceptions (where we want to deal with the rational
# form of the Float as a rational) at the source rather
# than assigning a mathematically loaded category of 'rational'
is_rational = None
is_irrational = None
is_number = True
is_real = True
is_extended_real = True
is_Float = True
_remove_non_digits = str.maketrans(dict.fromkeys("-+_."))
def __new__(cls, num, dps=None, precision=None):
if dps is not None and precision is not None:
raise ValueError('Both decimal and binary precision supplied. '
'Supply only one. ')
if isinstance(num, str):
_num = num = num.strip() # Python ignores leading and trailing space
num = num.replace(' ', '_').lower() # Float treats spaces as digit sep; E -> e
if num.startswith('.') and len(num) > 1:
num = '0' + num
elif num.startswith('-.') and len(num) > 2:
num = '-0.' + num[2:]
elif num in ('inf', '+inf'):
return S.Infinity
elif num == '-inf':
return S.NegativeInfinity
elif num == 'nan':
return S.NaN
elif not _literal_float(num):
raise ValueError('string-float not recognized: %s' % _num)
elif isinstance(num, float) and num == 0:
num = '0'
elif isinstance(num, float) and num == float('inf'):
return S.Infinity
elif isinstance(num, float) and num == float('-inf'):
return S.NegativeInfinity
elif isinstance(num, float) and math.isnan(num):
return S.NaN
elif isinstance(num, (SYMPY_INTS, Integer)):
num = str(num)
elif num is S.Infinity:
return num
elif num is S.NegativeInfinity:
return num
elif num is S.NaN:
return num
elif _is_numpy_instance(num): # support for numpy datatypes
num = _convert_numpy_types(num)
elif isinstance(num, mpmath.mpf):
if precision is None:
if dps is None:
precision = num.context.prec
num = num._mpf_
if dps is None and precision is None:
dps = 15
if isinstance(num, Float):
return num
if isinstance(num, str):
try:
Num = decimal.Decimal(num)
except decimal.InvalidOperation:
pass
else:
isint = '.' not in num
num, dps = _decimal_to_Rational_prec(Num)
if num.is_Integer and isint:
# 12e3 is shorthand for int, not float;
# 12.e3 would be the float version
dps = max(dps, num_digits(num))
dps = max(15, dps)
precision = dps_to_prec(dps)
elif precision == '' and dps is None or precision is None and dps == '':
if not isinstance(num, str):
raise ValueError('The null string can only be used when '
'the number to Float is passed as a string or an integer.')
try:
Num = decimal.Decimal(num)
except decimal.InvalidOperation:
raise ValueError('string-float not recognized by Decimal: %s' % num)
else:
isint = '.' not in num
num, dps = _decimal_to_Rational_prec(Num)
if num.is_Integer and isint:
# without dec, e-notation is short for int
dps = max(dps, num_digits(num))
precision = dps_to_prec(dps)
# decimal precision(dps) is set and maybe binary precision(precision)
# as well.From here on binary precision is used to compute the Float.
# Hence, if supplied use binary precision else translate from decimal
# precision.
if precision is None or precision == '':
precision = dps_to_prec(dps)
precision = int(precision)
if isinstance(num, float):
_mpf_ = mlib.from_float(num, precision, rnd)
elif isinstance(num, str):
_mpf_ = mlib.from_str(num, precision, rnd)
elif isinstance(num, decimal.Decimal):
if num.is_finite():
_mpf_ = mlib.from_str(str(num), precision, rnd)
elif num.is_nan():
return S.NaN
elif num.is_infinite():
if num > 0:
return S.Infinity
return S.NegativeInfinity
else:
raise ValueError("unexpected decimal value %s" % str(num))
elif isinstance(num, tuple) and len(num) in (3, 4):
if isinstance(num[1], str):
# it's a hexadecimal (coming from a pickled object)
num = list(num)
# If we're loading an object pickled in Python 2 into
# Python 3, we may need to strip a tailing 'L' because
# of a shim for int on Python 3, see issue #13470.
if num[1].endswith('L'):
num[1] = num[1][:-1]
# Strip leading '0x' - gmpy2 only documents such inputs
# with base prefix as valid when the 2nd argument (base) is 0.
# When mpmath uses Sage as the backend, however, it
# ends up including '0x' when preparing the picklable tuple.
# See issue #19690.
if num[1].startswith('0x'):
num[1] = num[1][2:]
# Now we can assume that it is in standard form
num[1] = MPZ(num[1], 16)
_mpf_ = tuple(num)
else:
if len(num) == 4:
# handle normalization hack
return Float._new(num, precision)
else:
if not all((
num[0] in (0, 1),
num[1] >= 0,
all(type(i) in (int, int) for i in num)
)):
raise ValueError('malformed mpf: %s' % (num,))
# don't compute number or else it may
# over/underflow
return Float._new(
(num[0], num[1], num[2], bitcount(num[1])),
precision)
elif isinstance(num, (Number, NumberSymbol)):
_mpf_ = num._as_mpf_val(precision)
else:
_mpf_ = mpmath.mpf(num, prec=precision)._mpf_
return cls._new(_mpf_, precision, zero=False)
@classmethod
def _new(cls, _mpf_, _prec, zero=True):
# special cases
if zero and _mpf_ == fzero:
return S.Zero # Float(0) -> 0.0; Float._new((0,0,0,0)) -> 0
elif _mpf_ == _mpf_nan:
return S.NaN
elif _mpf_ == _mpf_inf:
return S.Infinity
elif _mpf_ == _mpf_ninf:
return S.NegativeInfinity
obj = Expr.__new__(cls)
obj._mpf_ = mpf_norm(_mpf_, _prec)
obj._prec = _prec
return obj
def __getnewargs_ex__(self):
sign, man, exp, bc = self._mpf_
arg = (sign, hex(man)[2:], exp, bc)
kwargs = {'precision': self._prec}
return ((arg,), kwargs)
def _hashable_content(self):
return (self._mpf_, self._prec)
def floor(self):
return Integer(int(mlib.to_int(
mlib.mpf_floor(self._mpf_, self._prec))))
def ceiling(self):
return Integer(int(mlib.to_int(
mlib.mpf_ceil(self._mpf_, self._prec))))
def __floor__(self):
return self.floor()
def __ceil__(self):
return self.ceiling()
@property
def num(self):
return mpmath.mpf(self._mpf_)
def _as_mpf_val(self, prec):
rv = mpf_norm(self._mpf_, prec)
if rv != self._mpf_ and self._prec == prec:
debug(self._mpf_, rv)
return rv
def _as_mpf_op(self, prec):
return self._mpf_, max(prec, self._prec)
def _eval_is_finite(self):
if self._mpf_ in (_mpf_inf, _mpf_ninf):
return False
return True
def _eval_is_infinite(self):
if self._mpf_ in (_mpf_inf, _mpf_ninf):
return True
return False
def _eval_is_integer(self):
if self._mpf_ == fzero:
return True
if not int_valued(self):
return False
def _eval_is_negative(self):
if self._mpf_ in (_mpf_ninf, _mpf_inf):
return False
return self.num < 0
def _eval_is_positive(self):
if self._mpf_ in (_mpf_ninf, _mpf_inf):
return False
return self.num > 0
def _eval_is_extended_negative(self):
if self._mpf_ == _mpf_ninf:
return True
if self._mpf_ == _mpf_inf:
return False
return self.num < 0
def _eval_is_extended_positive(self):
if self._mpf_ == _mpf_inf:
return True
if self._mpf_ == _mpf_ninf:
return False
return self.num > 0
def _eval_is_zero(self):
return self._mpf_ == fzero
def __bool__(self):
return self._mpf_ != fzero
def __neg__(self):
if not self:
return self
return Float._new(mlib.mpf_neg(self._mpf_), self._prec)
@_sympifyit('other', NotImplemented)
def __add__(self, other):
if isinstance(other, Number) and global_parameters.evaluate:
rhs, prec = other._as_mpf_op(self._prec)
return Float._new(mlib.mpf_add(self._mpf_, rhs, prec, rnd), prec)
return Number.__add__(self, other)
@_sympifyit('other', NotImplemented)
def __sub__(self, other):
if isinstance(other, Number) and global_parameters.evaluate:
rhs, prec = other._as_mpf_op(self._prec)
return Float._new(mlib.mpf_sub(self._mpf_, rhs, prec, rnd), prec)
return Number.__sub__(self, other)
@_sympifyit('other', NotImplemented)
def __mul__(self, other):
if isinstance(other, Number) and global_parameters.evaluate:
rhs, prec = other._as_mpf_op(self._prec)
return Float._new(mlib.mpf_mul(self._mpf_, rhs, prec, rnd), prec)
return Number.__mul__(self, other)
@_sympifyit('other', NotImplemented)
def __truediv__(self, other):
if isinstance(other, Number) and other != 0 and global_parameters.evaluate:
rhs, prec = other._as_mpf_op(self._prec)
return Float._new(mlib.mpf_div(self._mpf_, rhs, prec, rnd), prec)
return Number.__truediv__(self, other)
@_sympifyit('other', NotImplemented)
def __mod__(self, other):
if isinstance(other, Rational) and other.q != 1 and global_parameters.evaluate:
# calculate mod with Rationals, *then* round the result
return Float(Rational.__mod__(Rational(self), other),
precision=self._prec)
if isinstance(other, Float) and global_parameters.evaluate:
r = self/other
if int_valued(r):
return Float(0, precision=max(self._prec, other._prec))
if isinstance(other, Number) and global_parameters.evaluate:
rhs, prec = other._as_mpf_op(self._prec)
return Float._new(mlib.mpf_mod(self._mpf_, rhs, prec, rnd), prec)
return Number.__mod__(self, other)
@_sympifyit('other', NotImplemented)
def __rmod__(self, other):
if isinstance(other, Float) and global_parameters.evaluate:
return other.__mod__(self)
if isinstance(other, Number) and global_parameters.evaluate:
rhs, prec = other._as_mpf_op(self._prec)
return Float._new(mlib.mpf_mod(rhs, self._mpf_, prec, rnd), prec)
return Number.__rmod__(self, other)
def _eval_power(self, expt):
"""
expt is symbolic object but not equal to 0, 1
(-p)**r -> exp(r*log(-p)) -> exp(r*(log(p) + I*Pi)) ->
-> p**r*(sin(Pi*r) + cos(Pi*r)*I)
"""
if equal_valued(self, 0):
if expt.is_extended_positive:
return self
if expt.is_extended_negative:
return S.ComplexInfinity
if isinstance(expt, Number):
if isinstance(expt, Integer):
prec = self._prec
return Float._new(
mlib.mpf_pow_int(self._mpf_, expt.p, prec, rnd), prec)
elif isinstance(expt, Rational) and \
expt.p == 1 and expt.q % 2 and self.is_negative:
return Pow(S.NegativeOne, expt, evaluate=False)*(
-self)._eval_power(expt)
expt, prec = expt._as_mpf_op(self._prec)
mpfself = self._mpf_
try:
y = mpf_pow(mpfself, expt, prec, rnd)
return Float._new(y, prec)
except mlib.ComplexResult:
re, im = mlib.mpc_pow(
(mpfself, fzero), (expt, fzero), prec, rnd)
return Float._new(re, prec) + \
Float._new(im, prec)*S.ImaginaryUnit
def __abs__(self):
return Float._new(mlib.mpf_abs(self._mpf_), self._prec)
def __int__(self):
if self._mpf_ == fzero:
return 0
return int(mlib.to_int(self._mpf_)) # uses round_fast = round_down
def __eq__(self, other):
if isinstance(other, float):
other = Float(other)
return Basic.__eq__(self, other)
def __ne__(self, other):
eq = self.__eq__(other)
if eq is NotImplemented:
return eq
else:
return not eq
def __hash__(self):
float_val = float(self)
if not math.isinf(float_val):
return hash(float_val)
return Basic.__hash__(self)
def _Frel(self, other, op):
try:
other = _sympify(other)
except SympifyError:
return NotImplemented
if other.is_Rational:
# test self*other.q <?> other.p without losing precision
'''
>>> f = Float(.1,2)
>>> i = 1234567890
>>> (f*i)._mpf_
(0, 471, 18, 9)
>>> mlib.mpf_mul(f._mpf_, mlib.from_int(i))
(0, 505555550955, -12, 39)
'''
smpf = mlib.mpf_mul(self._mpf_, mlib.from_int(other.q))
ompf = mlib.from_int(other.p)
return _sympify(bool(op(smpf, ompf)))
elif other.is_Float:
return _sympify(bool(
op(self._mpf_, other._mpf_)))
elif other.is_comparable and other not in (
S.Infinity, S.NegativeInfinity):
other = other.evalf(prec_to_dps(self._prec))
if other._prec > 1:
if other.is_Number:
return _sympify(bool(
op(self._mpf_, other._as_mpf_val(self._prec))))
def __gt__(self, other):
if isinstance(other, NumberSymbol):
return other.__lt__(self)
rv = self._Frel(other, mlib.mpf_gt)
if rv is None:
return Expr.__gt__(self, other)
return rv
def __ge__(self, other):
if isinstance(other, NumberSymbol):
return other.__le__(self)
rv = self._Frel(other, mlib.mpf_ge)
if rv is None:
return Expr.__ge__(self, other)
return rv
def __lt__(self, other):
if isinstance(other, NumberSymbol):
return other.__gt__(self)
rv = self._Frel(other, mlib.mpf_lt)
if rv is None:
return Expr.__lt__(self, other)
return rv
def __le__(self, other):
if isinstance(other, NumberSymbol):
return other.__ge__(self)
rv = self._Frel(other, mlib.mpf_le)
if rv is None:
return Expr.__le__(self, other)
return rv
def epsilon_eq(self, other, epsilon="1e-15"):
return abs(self - other) < Float(epsilon)
def __format__(self, format_spec):
return format(decimal.Decimal(str(self)), format_spec)
# Add sympify converters
_sympy_converter[float] = _sympy_converter[decimal.Decimal] = Float
# this is here to work nicely in Sage
RealNumber = Float
class Rational(Number):
"""Represents rational numbers (p/q) of any size.
Examples
========
>>> from sympy import Rational, nsimplify, S, pi
>>> Rational(1, 2)
1/2
Rational is unprejudiced in accepting input. If a float is passed, the
underlying value of the binary representation will be returned:
>>> Rational(.5)
1/2
>>> Rational(.2)
3602879701896397/18014398509481984
If the simpler representation of the float is desired then consider
limiting the denominator to the desired value or convert the float to
a string (which is roughly equivalent to limiting the denominator to
10**12):
>>> Rational(str(.2))
1/5
>>> Rational(.2).limit_denominator(10**12)
1/5
An arbitrarily precise Rational is obtained when a string literal is
passed:
>>> Rational("1.23")
123/100
>>> Rational('1e-2')
1/100
>>> Rational(".1")
1/10
>>> Rational('1e-2/3.2')
1/320
The conversion of other types of strings can be handled by
the sympify() function, and conversion of floats to expressions
or simple fractions can be handled with nsimplify:
>>> S('.[3]') # repeating digits in brackets
1/3
>>> S('3**2/10') # general expressions
9/10
>>> nsimplify(.3) # numbers that have a simple form
3/10
But if the input does not reduce to a literal Rational, an error will
be raised:
>>> Rational(pi)
Traceback (most recent call last):
...
TypeError: invalid input: pi
Low-level
---------
Access numerator and denominator as .p and .q:
>>> r = Rational(3, 4)
>>> r
3/4
>>> r.p
3
>>> r.q
4
Note that p and q return integers (not SymPy Integers) so some care
is needed when using them in expressions:
>>> r.p/r.q
0.75
If an unevaluated Rational is desired, ``gcd=1`` can be passed and
this will keep common divisors of the numerator and denominator
from being eliminated. It is not possible, however, to leave a
negative value in the denominator.
>>> Rational(2, 4, gcd=1)
2/4
>>> Rational(2, -4, gcd=1).q
4
See Also
========
sympy.core.sympify.sympify, sympy.simplify.simplify.nsimplify
"""
is_real = True
is_integer = False
is_rational = True
is_number = True
__slots__ = ('p', 'q')
p: int
q: int
is_Rational = True
@cacheit
def __new__(cls, p, q=None, gcd=None):
if q is None:
if isinstance(p, Rational):
return p
if isinstance(p, SYMPY_INTS):
pass
else:
if isinstance(p, (float, Float)):
return Rational(*_as_integer_ratio(p))
if not isinstance(p, str):
try:
p = sympify(p)
except (SympifyError, SyntaxError):
pass # error will raise below
else:
if p.count('/') > 1:
raise TypeError('invalid input: %s' % p)
p = p.replace(' ', '')
pq = p.rsplit('/', 1)
if len(pq) == 2:
p, q = pq
fp = fractions.Fraction(p)
fq = fractions.Fraction(q)
p = fp/fq
try:
p = fractions.Fraction(p)
except ValueError:
pass # error will raise below
else:
return Rational(p.numerator, p.denominator, 1)
if not isinstance(p, Rational):
raise TypeError('invalid input: %s' % p)
q = 1
gcd = 1
Q = 1
if not isinstance(p, SYMPY_INTS):
p = Rational(p)
Q *= p.q
p = p.p
else:
p = int(p)
if not isinstance(q, SYMPY_INTS):
q = Rational(q)
p *= q.q
Q *= q.p
else:
Q *= int(q)
q = Q
# p and q are now ints
if q == 0:
if p == 0:
if _errdict["divide"]:
raise ValueError("Indeterminate 0/0")
else:
return S.NaN
return S.ComplexInfinity
if q < 0:
q = -q
p = -p
if not gcd:
gcd = igcd(abs(p), q)
if gcd > 1:
p //= gcd
q //= gcd
if q == 1:
return Integer(p)
if p == 1 and q == 2:
return S.Half
obj = Expr.__new__(cls)
obj.p = p
obj.q = q
return obj
def limit_denominator(self, max_denominator=1000000):
"""Closest Rational to self with denominator at most max_denominator.
Examples
========
>>> from sympy import Rational
>>> Rational('3.141592653589793').limit_denominator(10)
22/7
>>> Rational('3.141592653589793').limit_denominator(100)
311/99
"""
f = fractions.Fraction(self.p, self.q)
return Rational(f.limit_denominator(fractions.Fraction(int(max_denominator))))
def __getnewargs__(self):
return (self.p, self.q)
def _hashable_content(self):
return (self.p, self.q)
def _eval_is_positive(self):
return self.p > 0
def _eval_is_zero(self):
return self.p == 0
def __neg__(self):
return Rational(-self.p, self.q)
@_sympifyit('other', NotImplemented)
def __add__(self, other):
if global_parameters.evaluate:
if isinstance(other, Integer):
return Rational(self.p + self.q*other.p, self.q, 1)
elif isinstance(other, Rational):
#TODO: this can probably be optimized more
return Rational(self.p*other.q + self.q*other.p, self.q*other.q)
elif isinstance(other, Float):
return other + self
else:
return Number.__add__(self, other)
return Number.__add__(self, other)
__radd__ = __add__
@_sympifyit('other', NotImplemented)
def __sub__(self, other):
if global_parameters.evaluate:
if isinstance(other, Integer):
return Rational(self.p - self.q*other.p, self.q, 1)
elif isinstance(other, Rational):
return Rational(self.p*other.q - self.q*other.p, self.q*other.q)
elif isinstance(other, Float):
return -other + self
else:
return Number.__sub__(self, other)
return Number.__sub__(self, other)
@_sympifyit('other', NotImplemented)
def __rsub__(self, other):
if global_parameters.evaluate:
if isinstance(other, Integer):
return Rational(self.q*other.p - self.p, self.q, 1)
elif isinstance(other, Rational):
return Rational(self.q*other.p - self.p*other.q, self.q*other.q)
elif isinstance(other, Float):
return -self + other
else:
return Number.__rsub__(self, other)
return Number.__rsub__(self, other)
@_sympifyit('other', NotImplemented)
def __mul__(self, other):
if global_parameters.evaluate:
if isinstance(other, Integer):
return Rational(self.p*other.p, self.q, igcd(other.p, self.q))
elif isinstance(other, Rational):
return Rational(self.p*other.p, self.q*other.q, igcd(self.p, other.q)*igcd(self.q, other.p))
elif isinstance(other, Float):
return other*self
else:
return Number.__mul__(self, other)
return Number.__mul__(self, other)
__rmul__ = __mul__
@_sympifyit('other', NotImplemented)
def __truediv__(self, other):
if global_parameters.evaluate:
if isinstance(other, Integer):
if self.p and other.p == S.Zero:
return S.ComplexInfinity
else:
return Rational(self.p, self.q*other.p, igcd(self.p, other.p))
elif isinstance(other, Rational):
return Rational(self.p*other.q, self.q*other.p, igcd(self.p, other.p)*igcd(self.q, other.q))
elif isinstance(other, Float):
return self*(1/other)
else:
return Number.__truediv__(self, other)
return Number.__truediv__(self, other)
@_sympifyit('other', NotImplemented)
def __rtruediv__(self, other):
if global_parameters.evaluate:
if isinstance(other, Integer):
return Rational(other.p*self.q, self.p, igcd(self.p, other.p))
elif isinstance(other, Rational):
return Rational(other.p*self.q, other.q*self.p, igcd(self.p, other.p)*igcd(self.q, other.q))
elif isinstance(other, Float):
return other*(1/self)
else:
return Number.__rtruediv__(self, other)
return Number.__rtruediv__(self, other)
@_sympifyit('other', NotImplemented)
def __mod__(self, other):
if global_parameters.evaluate:
if isinstance(other, Rational):
n = (self.p*other.q) // (other.p*self.q)
return Rational(self.p*other.q - n*other.p*self.q, self.q*other.q)
if isinstance(other, Float):
# calculate mod with Rationals, *then* round the answer
return Float(self.__mod__(Rational(other)),
precision=other._prec)
return Number.__mod__(self, other)
return Number.__mod__(self, other)
@_sympifyit('other', NotImplemented)
def __rmod__(self, other):
if isinstance(other, Rational):
return Rational.__mod__(other, self)
return Number.__rmod__(self, other)
def _eval_power(self, expt):
if isinstance(expt, Number):
if isinstance(expt, Float):
return self._eval_evalf(expt._prec)**expt
if expt.is_extended_negative:
# (3/4)**-2 -> (4/3)**2
ne = -expt
if (ne is S.One):
return Rational(self.q, self.p)
if self.is_negative:
return S.NegativeOne**expt*Rational(self.q, -self.p)**ne
else:
return Rational(self.q, self.p)**ne
if expt is S.Infinity: # -oo already caught by test for negative
if self.p > self.q:
# (3/2)**oo -> oo
return S.Infinity
if self.p < -self.q:
# (-3/2)**oo -> oo + I*oo
return S.Infinity + S.Infinity*S.ImaginaryUnit
return S.Zero
if isinstance(expt, Integer):
# (4/3)**2 -> 4**2 / 3**2
return Rational(self.p**expt.p, self.q**expt.p, 1)
if isinstance(expt, Rational):
intpart = expt.p // expt.q
if intpart:
intpart += 1
remfracpart = intpart*expt.q - expt.p
ratfracpart = Rational(remfracpart, expt.q)
if self.p != 1:
return Integer(self.p)**expt*Integer(self.q)**ratfracpart*Rational(1, self.q**intpart, 1)
return Integer(self.q)**ratfracpart*Rational(1, self.q**intpart, 1)
else:
remfracpart = expt.q - expt.p
ratfracpart = Rational(remfracpart, expt.q)
if self.p != 1:
return Integer(self.p)**expt*Integer(self.q)**ratfracpart*Rational(1, self.q, 1)
return Integer(self.q)**ratfracpart*Rational(1, self.q, 1)
if self.is_extended_negative and expt.is_even:
return (-self)**expt
return
def _as_mpf_val(self, prec):
return mlib.from_rational(self.p, self.q, prec, rnd)
def _mpmath_(self, prec, rnd):
return mpmath.make_mpf(mlib.from_rational(self.p, self.q, prec, rnd))
def __abs__(self):
return Rational(abs(self.p), self.q)
def __int__(self):
p, q = self.p, self.q
if p < 0:
return -int(-p//q)
return int(p//q)
def floor(self):
return Integer(self.p // self.q)
def ceiling(self):
return -Integer(-self.p // self.q)
def __floor__(self):
return self.floor()
def __ceil__(self):
return self.ceiling()
def __eq__(self, other):
try:
other = _sympify(other)
except SympifyError:
return NotImplemented
if not isinstance(other, Number):
# S(0) == S.false is False
# S(0) == False is True
return False
if other.is_NumberSymbol:
if other.is_irrational:
return False
return other.__eq__(self)
if other.is_Rational:
# a Rational is always in reduced form so will never be 2/4
# so we can just check equivalence of args
return self.p == other.p and self.q == other.q
return False
def __ne__(self, other):
return not self == other
def _Rrel(self, other, attr):
# if you want self < other, pass self, other, __gt__
try:
other = _sympify(other)
except SympifyError:
return NotImplemented
if other.is_Number:
op = None
s, o = self, other
if other.is_NumberSymbol:
op = getattr(o, attr)
elif other.is_Float:
op = getattr(o, attr)
elif other.is_Rational:
s, o = Integer(s.p*o.q), Integer(s.q*o.p)
op = getattr(o, attr)
if op:
return op(s)
if o.is_number and o.is_extended_real:
return Integer(s.p), s.q*o
def __gt__(self, other):
rv = self._Rrel(other, '__lt__')
if rv is None:
rv = self, other
elif not isinstance(rv, tuple):
return rv
return Expr.__gt__(*rv)
def __ge__(self, other):
rv = self._Rrel(other, '__le__')
if rv is None:
rv = self, other
elif not isinstance(rv, tuple):
return rv
return Expr.__ge__(*rv)
def __lt__(self, other):
rv = self._Rrel(other, '__gt__')
if rv is None:
rv = self, other
elif not isinstance(rv, tuple):
return rv
return Expr.__lt__(*rv)
def __le__(self, other):
rv = self._Rrel(other, '__ge__')
if rv is None:
rv = self, other
elif not isinstance(rv, tuple):
return rv
return Expr.__le__(*rv)
def __hash__(self):
return super().__hash__()
def factors(self, limit=None, use_trial=True, use_rho=False,
use_pm1=False, verbose=False, visual=False):
"""A wrapper to factorint which return factors of self that are
smaller than limit (or cheap to compute). Special methods of
factoring are disabled by default so that only trial division is used.
"""
from sympy.ntheory.factor_ import factorrat
return factorrat(self, limit=limit, use_trial=use_trial,
use_rho=use_rho, use_pm1=use_pm1,
verbose=verbose).copy()
@property
def numerator(self):
return self.p
@property
def denominator(self):
return self.q
@_sympifyit('other', NotImplemented)
def gcd(self, other):
if isinstance(other, Rational):
if other == S.Zero:
return other
return Rational(
igcd(self.p, other.p),
ilcm(self.q, other.q))
return Number.gcd(self, other)
@_sympifyit('other', NotImplemented)
def lcm(self, other):
if isinstance(other, Rational):
return Rational(
self.p // igcd(self.p, other.p) * other.p,
igcd(self.q, other.q))
return Number.lcm(self, other)
def as_numer_denom(self):
return Integer(self.p), Integer(self.q)
def as_content_primitive(self, radical=False, clear=True):
"""Return the tuple (R, self/R) where R is the positive Rational
extracted from self.
Examples
========
>>> from sympy import S
>>> (S(-3)/2).as_content_primitive()
(3/2, -1)
See docstring of Expr.as_content_primitive for more examples.
"""
if self:
if self.is_positive:
return self, S.One
return -self, S.NegativeOne
return S.One, self
def as_coeff_Mul(self, rational=False):
"""Efficiently extract the coefficient of a product."""
return self, S.One
def as_coeff_Add(self, rational=False):
"""Efficiently extract the coefficient of a summation."""
return self, S.Zero
class Integer(Rational):
"""Represents integer numbers of any size.
Examples
========
>>> from sympy import Integer
>>> Integer(3)
3
If a float or a rational is passed to Integer, the fractional part
will be discarded; the effect is of rounding toward zero.
>>> Integer(3.8)
3
>>> Integer(-3.8)
-3
A string is acceptable input if it can be parsed as an integer:
>>> Integer("9" * 20)
99999999999999999999
It is rarely needed to explicitly instantiate an Integer, because
Python integers are automatically converted to Integer when they
are used in SymPy expressions.
"""
q = 1
is_integer = True
is_number = True
is_Integer = True
__slots__ = ()
def _as_mpf_val(self, prec):
return mlib.from_int(self.p, prec, rnd)
def _mpmath_(self, prec, rnd):
return mpmath.make_mpf(self._as_mpf_val(prec))
@cacheit
def __new__(cls, i):
if isinstance(i, str):
i = i.replace(' ', '')
# whereas we cannot, in general, make a Rational from an
# arbitrary expression, we can make an Integer unambiguously
# (except when a non-integer expression happens to round to
# an integer). So we proceed by taking int() of the input and
# let the int routines determine whether the expression can
# be made into an int or whether an error should be raised.
try:
ival = int(i)
except TypeError:
raise TypeError(
"Argument of Integer should be of numeric type, got %s." % i)
# We only work with well-behaved integer types. This converts, for
# example, numpy.int32 instances.
if ival == 1:
return S.One
if ival == -1:
return S.NegativeOne
if ival == 0:
return S.Zero
obj = Expr.__new__(cls)
obj.p = ival
return obj
def __getnewargs__(self):
return (self.p,)
# Arithmetic operations are here for efficiency
def __int__(self):
return self.p
def floor(self):
return Integer(self.p)
def ceiling(self):
return Integer(self.p)
def __floor__(self):
return self.floor()
def __ceil__(self):
return self.ceiling()
def __neg__(self):
return Integer(-self.p)
def __abs__(self):
if self.p >= 0:
return self
else:
return Integer(-self.p)
def __divmod__(self, other):
if isinstance(other, Integer) and global_parameters.evaluate:
return Tuple(*(divmod(self.p, other.p)))
else:
return Number.__divmod__(self, other)
def __rdivmod__(self, other):
if isinstance(other, int) and global_parameters.evaluate:
return Tuple(*(divmod(other, self.p)))
else:
try:
other = Number(other)
except TypeError:
msg = "unsupported operand type(s) for divmod(): '%s' and '%s'"
oname = type(other).__name__
sname = type(self).__name__
raise TypeError(msg % (oname, sname))
return Number.__divmod__(other, self)
# TODO make it decorator + bytecodehacks?
def __add__(self, other):
if global_parameters.evaluate:
if isinstance(other, int):
return Integer(self.p + other)
elif isinstance(other, Integer):
return Integer(self.p + other.p)
elif isinstance(other, Rational):
return Rational(self.p*other.q + other.p, other.q, 1)
return Rational.__add__(self, other)
else:
return Add(self, other)
def __radd__(self, other):
if global_parameters.evaluate:
if isinstance(other, int):
return Integer(other + self.p)
elif isinstance(other, Rational):
return Rational(other.p + self.p*other.q, other.q, 1)
return Rational.__radd__(self, other)
return Rational.__radd__(self, other)
def __sub__(self, other):
if global_parameters.evaluate:
if isinstance(other, int):
return Integer(self.p - other)
elif isinstance(other, Integer):
return Integer(self.p - other.p)
elif isinstance(other, Rational):
return Rational(self.p*other.q - other.p, other.q, 1)
return Rational.__sub__(self, other)
return Rational.__sub__(self, other)
def __rsub__(self, other):
if global_parameters.evaluate:
if isinstance(other, int):
return Integer(other - self.p)
elif isinstance(other, Rational):
return Rational(other.p - self.p*other.q, other.q, 1)
return Rational.__rsub__(self, other)
return Rational.__rsub__(self, other)
def __mul__(self, other):
if global_parameters.evaluate:
if isinstance(other, int):
return Integer(self.p*other)
elif isinstance(other, Integer):
return Integer(self.p*other.p)
elif isinstance(other, Rational):
return Rational(self.p*other.p, other.q, igcd(self.p, other.q))
return Rational.__mul__(self, other)
return Rational.__mul__(self, other)
def __rmul__(self, other):
if global_parameters.evaluate:
if isinstance(other, int):
return Integer(other*self.p)
elif isinstance(other, Rational):
return Rational(other.p*self.p, other.q, igcd(self.p, other.q))
return Rational.__rmul__(self, other)
return Rational.__rmul__(self, other)
def __mod__(self, other):
if global_parameters.evaluate:
if isinstance(other, int):
return Integer(self.p % other)
elif isinstance(other, Integer):
return Integer(self.p % other.p)
return Rational.__mod__(self, other)
return Rational.__mod__(self, other)
def __rmod__(self, other):
if global_parameters.evaluate:
if isinstance(other, int):
return Integer(other % self.p)
elif isinstance(other, Integer):
return Integer(other.p % self.p)
return Rational.__rmod__(self, other)
return Rational.__rmod__(self, other)
def __eq__(self, other):
if isinstance(other, int):
return (self.p == other)
elif isinstance(other, Integer):
return (self.p == other.p)
return Rational.__eq__(self, other)
def __ne__(self, other):
return not self == other
def __gt__(self, other):
try:
other = _sympify(other)
except SympifyError:
return NotImplemented
if other.is_Integer:
return _sympify(self.p > other.p)
return Rational.__gt__(self, other)
def __lt__(self, other):
try:
other = _sympify(other)
except SympifyError:
return NotImplemented
if other.is_Integer:
return _sympify(self.p < other.p)
return Rational.__lt__(self, other)
def __ge__(self, other):
try:
other = _sympify(other)
except SympifyError:
return NotImplemented
if other.is_Integer:
return _sympify(self.p >= other.p)
return Rational.__ge__(self, other)
def __le__(self, other):
try:
other = _sympify(other)
except SympifyError:
return NotImplemented
if other.is_Integer:
return _sympify(self.p <= other.p)
return Rational.__le__(self, other)
def __hash__(self):
return hash(self.p)
def __index__(self):
return self.p
########################################
def _eval_is_odd(self):
return bool(self.p % 2)
def _eval_power(self, expt):
"""
Tries to do some simplifications on self**expt
Returns None if no further simplifications can be done.
Explanation
===========
When exponent is a fraction (so we have for example a square root),
we try to find a simpler representation by factoring the argument
up to factors of 2**15, e.g.
- sqrt(4) becomes 2
- sqrt(-4) becomes 2*I
- (2**(3+7)*3**(6+7))**Rational(1,7) becomes 6*18**(3/7)
Further simplification would require a special call to factorint on
the argument which is not done here for sake of speed.
"""
from sympy.ntheory.factor_ import perfect_power
if expt is S.Infinity:
if self.p > S.One:
return S.Infinity
# cases -1, 0, 1 are done in their respective classes
return S.Infinity + S.ImaginaryUnit*S.Infinity
if expt is S.NegativeInfinity:
return Rational(1, self, 1)**S.Infinity
if not isinstance(expt, Number):
# simplify when expt is even
# (-2)**k --> 2**k
if self.is_negative and expt.is_even:
return (-self)**expt
if isinstance(expt, Float):
# Rational knows how to exponentiate by a Float
return super()._eval_power(expt)
if not isinstance(expt, Rational):
return
if expt is S.Half and self.is_negative:
# we extract I for this special case since everyone is doing so
return S.ImaginaryUnit*Pow(-self, expt)
if expt.is_negative:
# invert base and change sign on exponent
ne = -expt
if self.is_negative:
return S.NegativeOne**expt*Rational(1, -self, 1)**ne
else:
return Rational(1, self.p, 1)**ne
# see if base is a perfect root, sqrt(4) --> 2
x, xexact = integer_nthroot(abs(self.p), expt.q)
if xexact:
# if it's a perfect root we've finished
result = Integer(x**abs(expt.p))
if self.is_negative:
result *= S.NegativeOne**expt
return result
# The following is an algorithm where we collect perfect roots
# from the factors of base.
# if it's not an nth root, it still might be a perfect power
b_pos = int(abs(self.p))
p = perfect_power(b_pos)
if p is not False:
dict = {p[0]: p[1]}
else:
dict = Integer(b_pos).factors(limit=2**15)
# now process the dict of factors
out_int = 1 # integer part
out_rad = 1 # extracted radicals
sqr_int = 1
sqr_gcd = 0
sqr_dict = {}
for prime, exponent in dict.items():
exponent *= expt.p
# remove multiples of expt.q: (2**12)**(1/10) -> 2*(2**2)**(1/10)
div_e, div_m = divmod(exponent, expt.q)
if div_e > 0:
out_int *= prime**div_e
if div_m > 0:
# see if the reduced exponent shares a gcd with e.q
# (2**2)**(1/10) -> 2**(1/5)
g = igcd(div_m, expt.q)
if g != 1:
out_rad *= Pow(prime, Rational(div_m//g, expt.q//g, 1))
else:
sqr_dict[prime] = div_m
# identify gcd of remaining powers
for p, ex in sqr_dict.items():
if sqr_gcd == 0:
sqr_gcd = ex
else:
sqr_gcd = igcd(sqr_gcd, ex)
if sqr_gcd == 1:
break
for k, v in sqr_dict.items():
sqr_int *= k**(v//sqr_gcd)
if sqr_int == b_pos and out_int == 1 and out_rad == 1:
result = None
else:
result = out_int*out_rad*Pow(sqr_int, Rational(sqr_gcd, expt.q))
if self.is_negative:
result *= Pow(S.NegativeOne, expt)
return result
def _eval_is_prime(self):
from sympy.ntheory.primetest import isprime
return isprime(self)
def _eval_is_composite(self):
if self > 1:
return fuzzy_not(self.is_prime)
else:
return False
def as_numer_denom(self):
return self, S.One
@_sympifyit('other', NotImplemented)
def __floordiv__(self, other):
if not isinstance(other, Expr):
return NotImplemented
if isinstance(other, Integer):
return Integer(self.p // other)
return divmod(self, other)[0]
def __rfloordiv__(self, other):
return Integer(Integer(other).p // self.p)
# These bitwise operations (__lshift__, __rlshift__, ..., __invert__) are defined
# for Integer only and not for general SymPy expressions. This is to achieve
# compatibility with the numbers.Integral ABC which only defines these operations
# among instances of numbers.Integral. Therefore, these methods check explicitly for
# integer types rather than using sympify because they should not accept arbitrary
# symbolic expressions and there is no symbolic analogue of numbers.Integral's
# bitwise operations.
def __lshift__(self, other):
if isinstance(other, (int, Integer, numbers.Integral)):
return Integer(self.p << int(other))
else:
return NotImplemented
def __rlshift__(self, other):
if isinstance(other, (int, numbers.Integral)):
return Integer(int(other) << self.p)
else:
return NotImplemented
def __rshift__(self, other):
if isinstance(other, (int, Integer, numbers.Integral)):
return Integer(self.p >> int(other))
else:
return NotImplemented
def __rrshift__(self, other):
if isinstance(other, (int, numbers.Integral)):
return Integer(int(other) >> self.p)
else:
return NotImplemented
def __and__(self, other):
if isinstance(other, (int, Integer, numbers.Integral)):
return Integer(self.p & int(other))
else:
return NotImplemented
def __rand__(self, other):
if isinstance(other, (int, numbers.Integral)):
return Integer(int(other) & self.p)
else:
return NotImplemented
def __xor__(self, other):
if isinstance(other, (int, Integer, numbers.Integral)):
return Integer(self.p ^ int(other))
else:
return NotImplemented
def __rxor__(self, other):
if isinstance(other, (int, numbers.Integral)):
return Integer(int(other) ^ self.p)
else:
return NotImplemented
def __or__(self, other):
if isinstance(other, (int, Integer, numbers.Integral)):
return Integer(self.p | int(other))
else:
return NotImplemented
def __ror__(self, other):
if isinstance(other, (int, numbers.Integral)):
return Integer(int(other) | self.p)
else:
return NotImplemented
def __invert__(self):
return Integer(~self.p)
# Add sympify converters
_sympy_converter[int] = Integer
class AlgebraicNumber(Expr):
r"""
Class for representing algebraic numbers in SymPy.
Symbolically, an instance of this class represents an element
$\alpha \in \mathbb{Q}(\theta) \hookrightarrow \mathbb{C}$. That is, the
algebraic number $\alpha$ is represented as an element of a particular
number field $\mathbb{Q}(\theta)$, with a particular embedding of this
field into the complex numbers.
Formally, the primitive element $\theta$ is given by two data points: (1)
its minimal polynomial (which defines $\mathbb{Q}(\theta)$), and (2) a
particular complex number that is a root of this polynomial (which defines
the embedding $\mathbb{Q}(\theta) \hookrightarrow \mathbb{C}$). Finally,
the algebraic number $\alpha$ which we represent is then given by the
coefficients of a polynomial in $\theta$.
"""
__slots__ = ('rep', 'root', 'alias', 'minpoly', '_own_minpoly')
is_AlgebraicNumber = True
is_algebraic = True
is_number = True
kind = NumberKind
# Optional alias symbol is not free.
# Actually, alias should be a Str, but some methods
# expect that it be an instance of Expr.
free_symbols: set[Basic] = set()
def __new__(cls, expr, coeffs=None, alias=None, **args):
r"""
Construct a new algebraic number $\alpha$ belonging to a number field
$k = \mathbb{Q}(\theta)$.
There are four instance attributes to be determined:
=========== ============================================================================
Attribute Type/Meaning
=========== ============================================================================
``root`` :py:class:`~.Expr` for $\theta$ as a complex number
``minpoly`` :py:class:`~.Poly`, the minimal polynomial of $\theta$
``rep`` :py:class:`~sympy.polys.polyclasses.DMP` giving $\alpha$ as poly in $\theta$
``alias`` :py:class:`~.Symbol` for $\theta$, or ``None``
=========== ============================================================================
See Parameters section for how they are determined.
Parameters
==========
expr : :py:class:`~.Expr`, or pair $(m, r)$
There are three distinct modes of construction, depending on what
is passed as *expr*.
**(1)** *expr* is an :py:class:`~.AlgebraicNumber`:
In this case we begin by copying all four instance attributes from
*expr*. If *coeffs* were also given, we compose the two coeff
polynomials (see below). If an *alias* was given, it overrides.
**(2)** *expr* is any other type of :py:class:`~.Expr`:
Then ``root`` will equal *expr*. Therefore it
must express an algebraic quantity, and we will compute its
``minpoly``.
**(3)** *expr* is an ordered pair $(m, r)$ giving the
``minpoly`` $m$, and a ``root`` $r$ thereof, which together
define $\theta$. In this case $m$ may be either a univariate
:py:class:`~.Poly` or any :py:class:`~.Expr` which represents the
same, while $r$ must be some :py:class:`~.Expr` representing a
complex number that is a root of $m$, including both explicit
expressions in radicals, and instances of
:py:class:`~.ComplexRootOf` or :py:class:`~.AlgebraicNumber`.
coeffs : list, :py:class:`~.ANP`, None, optional (default=None)
This defines ``rep``, giving the algebraic number $\alpha$ as a
polynomial in $\theta$.
If a list, the elements should be integers or rational numbers.
If an :py:class:`~.ANP`, we take its coefficients (using its
:py:meth:`~.ANP.to_list()` method). If ``None``, then the list of
coefficients defaults to ``[1, 0]``, meaning that $\alpha = \theta$
is the primitive element of the field.
If *expr* was an :py:class:`~.AlgebraicNumber`, let $g(x)$ be its
``rep`` polynomial, and let $f(x)$ be the polynomial defined by
*coeffs*. Then ``self.rep`` will represent the composition
$(f \circ g)(x)$.
alias : str, :py:class:`~.Symbol`, None, optional (default=None)
This is a way to provide a name for the primitive element. We
described several ways in which the *expr* argument can define the
value of the primitive element, but none of these methods gave it
a name. Here, for example, *alias* could be set as
``Symbol('theta')``, in order to make this symbol appear when
$\alpha$ is printed, or rendered as a polynomial, using the
:py:meth:`~.as_poly()` method.
Examples
========
Recall that we are constructing an algebraic number as a field element
$\alpha \in \mathbb{Q}(\theta)$.
>>> from sympy import AlgebraicNumber, sqrt, CRootOf, S
>>> from sympy.abc import x
Example (1): $\alpha = \theta = \sqrt{2}$
>>> a1 = AlgebraicNumber(sqrt(2))
>>> a1.minpoly_of_element().as_expr(x)
x**2 - 2
>>> a1.evalf(10)
1.414213562
Example (2): $\alpha = 3 \sqrt{2} - 5$, $\theta = \sqrt{2}$. We can
either build on the last example:
>>> a2 = AlgebraicNumber(a1, [3, -5])
>>> a2.as_expr()
-5 + 3*sqrt(2)
or start from scratch:
>>> a2 = AlgebraicNumber(sqrt(2), [3, -5])
>>> a2.as_expr()
-5 + 3*sqrt(2)
Example (3): $\alpha = 6 \sqrt{2} - 11$, $\theta = \sqrt{2}$. Again we
can build on the previous example, and we see that the coeff polys are
composed:
>>> a3 = AlgebraicNumber(a2, [2, -1])
>>> a3.as_expr()
-11 + 6*sqrt(2)
reflecting the fact that $(2x - 1) \circ (3x - 5) = 6x - 11$.
Example (4): $\alpha = \sqrt{2}$, $\theta = \sqrt{2} + \sqrt{3}$. The
easiest way is to use the :py:func:`~.to_number_field()` function:
>>> from sympy import to_number_field
>>> a4 = to_number_field(sqrt(2), sqrt(2) + sqrt(3))
>>> a4.minpoly_of_element().as_expr(x)
x**2 - 2
>>> a4.to_root()
sqrt(2)
>>> a4.primitive_element()
sqrt(2) + sqrt(3)
>>> a4.coeffs()
[1/2, 0, -9/2, 0]
but if you already knew the right coefficients, you could construct it
directly:
>>> a4 = AlgebraicNumber(sqrt(2) + sqrt(3), [S(1)/2, 0, S(-9)/2, 0])
>>> a4.to_root()
sqrt(2)
>>> a4.primitive_element()
sqrt(2) + sqrt(3)
Example (5): Construct the Golden Ratio as an element of the 5th
cyclotomic field, supposing we already know its coefficients. This time
we introduce the alias $\zeta$ for the primitive element of the field:
>>> from sympy import cyclotomic_poly
>>> from sympy.abc import zeta
>>> a5 = AlgebraicNumber(CRootOf(cyclotomic_poly(5), -1),
... [-1, -1, 0, 0], alias=zeta)
>>> a5.as_poly().as_expr()
-zeta**3 - zeta**2
>>> a5.evalf()
1.61803398874989
(The index ``-1`` to ``CRootOf`` selects the complex root with the
largest real and imaginary parts, which in this case is
$\mathrm{e}^{2i\pi/5}$. See :py:class:`~.ComplexRootOf`.)
Example (6): Building on the last example, construct the number
$2 \phi \in \mathbb{Q}(\phi)$, where $\phi$ is the Golden Ratio:
>>> from sympy.abc import phi
>>> a6 = AlgebraicNumber(a5.to_root(), coeffs=[2, 0], alias=phi)
>>> a6.as_poly().as_expr()
2*phi
>>> a6.primitive_element().evalf()
1.61803398874989
Note that we needed to use ``a5.to_root()``, since passing ``a5`` as
the first argument would have constructed the number $2 \phi$ as an
element of the field $\mathbb{Q}(\zeta)$:
>>> a6_wrong = AlgebraicNumber(a5, coeffs=[2, 0])
>>> a6_wrong.as_poly().as_expr()
-2*zeta**3 - 2*zeta**2
>>> a6_wrong.primitive_element().evalf()
0.309016994374947 + 0.951056516295154*I
"""
from sympy.polys.polyclasses import ANP, DMP
from sympy.polys.numberfields import minimal_polynomial
expr = sympify(expr)
rep0 = None
alias0 = None
if isinstance(expr, (tuple, Tuple)):
minpoly, root = expr
if not minpoly.is_Poly:
from sympy.polys.polytools import Poly
minpoly = Poly(minpoly)
elif expr.is_AlgebraicNumber:
minpoly, root, rep0, alias0 = (expr.minpoly, expr.root,
expr.rep, expr.alias)
else:
minpoly, root = minimal_polynomial(
expr, args.get('gen'), polys=True), expr
dom = minpoly.get_domain()
if coeffs is not None:
if not isinstance(coeffs, ANP):
rep = DMP.from_sympy_list(sympify(coeffs), 0, dom)
scoeffs = Tuple(*coeffs)
else:
rep = DMP.from_list(coeffs.to_list(), 0, dom)
scoeffs = Tuple(*coeffs.to_list())
else:
rep = DMP.from_list([1, 0], 0, dom)
scoeffs = Tuple(1, 0)
if rep0 is not None:
from sympy.polys.densetools import dup_compose
c = dup_compose(rep.to_list(), rep0.to_list(), dom)
rep = DMP.from_list(c, 0, dom)
scoeffs = Tuple(*c)
if rep.degree() >= minpoly.degree():
rep = rep.rem(minpoly.rep)
sargs = (root, scoeffs)
alias = alias or alias0
if alias is not None:
from .symbol import Symbol
if not isinstance(alias, Symbol):
alias = Symbol(alias)
sargs = sargs + (alias,)
obj = Expr.__new__(cls, *sargs)
obj.rep = rep
obj.root = root
obj.alias = alias
obj.minpoly = minpoly
obj._own_minpoly = None
return obj
def __hash__(self):
return super().__hash__()
def _eval_evalf(self, prec):
return self.as_expr()._evalf(prec)
@property
def is_aliased(self):
"""Returns ``True`` if ``alias`` was set. """
return self.alias is not None
def as_poly(self, x=None):
"""Create a Poly instance from ``self``. """
from sympy.polys.polytools import Poly, PurePoly
if x is not None:
return Poly.new(self.rep, x)
else:
if self.alias is not None:
return Poly.new(self.rep, self.alias)
else:
from .symbol import Dummy
return PurePoly.new(self.rep, Dummy('x'))
def as_expr(self, x=None):
"""Create a Basic expression from ``self``. """
return self.as_poly(x or self.root).as_expr().expand()
def coeffs(self):
"""Returns all SymPy coefficients of an algebraic number. """
return [ self.rep.dom.to_sympy(c) for c in self.rep.all_coeffs() ]
def native_coeffs(self):
"""Returns all native coefficients of an algebraic number. """
return self.rep.all_coeffs()
def to_algebraic_integer(self):
"""Convert ``self`` to an algebraic integer. """
from sympy.polys.polytools import Poly
f = self.minpoly
if f.LC() == 1:
return self
coeff = f.LC()**(f.degree() - 1)
poly = f.compose(Poly(f.gen/f.LC()))
minpoly = poly*coeff
root = f.LC()*self.root
return AlgebraicNumber((minpoly, root), self.coeffs())
def _eval_simplify(self, **kwargs):
from sympy.polys.rootoftools import CRootOf
from sympy.polys import minpoly
measure, ratio = kwargs['measure'], kwargs['ratio']
for r in [r for r in self.minpoly.all_roots() if r.func != CRootOf]:
if minpoly(self.root - r).is_Symbol:
# use the matching root if it's simpler
if measure(r) < ratio*measure(self.root):
return AlgebraicNumber(r)
return self
def field_element(self, coeffs):
r"""
Form another element of the same number field.
Explanation
===========
If we represent $\alpha \in \mathbb{Q}(\theta)$, form another element
$\beta \in \mathbb{Q}(\theta)$ of the same number field.
Parameters
==========
coeffs : list, :py:class:`~.ANP`
Like the *coeffs* arg to the class
:py:meth:`constructor<.AlgebraicNumber.__new__>`, defines the
new element as a polynomial in the primitive element.
If a list, the elements should be integers or rational numbers.
If an :py:class:`~.ANP`, we take its coefficients (using its
:py:meth:`~.ANP.to_list()` method).
Examples
========
>>> from sympy import AlgebraicNumber, sqrt
>>> a = AlgebraicNumber(sqrt(5), [-1, 1])
>>> b = a.field_element([3, 2])
>>> print(a)
1 - sqrt(5)
>>> print(b)
2 + 3*sqrt(5)
>>> print(b.primitive_element() == a.primitive_element())
True
See Also
========
AlgebraicNumber
"""
return AlgebraicNumber(
(self.minpoly, self.root), coeffs=coeffs, alias=self.alias)
@property
def is_primitive_element(self):
r"""
Say whether this algebraic number $\alpha \in \mathbb{Q}(\theta)$ is
equal to the primitive element $\theta$ for its field.
"""
c = self.coeffs()
# Second case occurs if self.minpoly is linear:
return c == [1, 0] or c == [self.root]
def primitive_element(self):
r"""
Get the primitive element $\theta$ for the number field
$\mathbb{Q}(\theta)$ to which this algebraic number $\alpha$ belongs.
Returns
=======
AlgebraicNumber
"""
if self.is_primitive_element:
return self
return self.field_element([1, 0])
def to_primitive_element(self, radicals=True):
r"""
Convert ``self`` to an :py:class:`~.AlgebraicNumber` instance that is
equal to its own primitive element.
Explanation
===========
If we represent $\alpha \in \mathbb{Q}(\theta)$, $\alpha \neq \theta$,
construct a new :py:class:`~.AlgebraicNumber` that represents
$\alpha \in \mathbb{Q}(\alpha)$.
Examples
========
>>> from sympy import sqrt, to_number_field
>>> from sympy.abc import x
>>> a = to_number_field(sqrt(2), sqrt(2) + sqrt(3))
The :py:class:`~.AlgebraicNumber` ``a`` represents the number
$\sqrt{2}$ in the field $\mathbb{Q}(\sqrt{2} + \sqrt{3})$. Rendering
``a`` as a polynomial,
>>> a.as_poly().as_expr(x)
x**3/2 - 9*x/2
reflects the fact that $\sqrt{2} = \theta^3/2 - 9 \theta/2$, where
$\theta = \sqrt{2} + \sqrt{3}$.
``a`` is not equal to its own primitive element. Its minpoly
>>> a.minpoly.as_poly().as_expr(x)
x**4 - 10*x**2 + 1
is that of $\theta$.
Converting to a primitive element,
>>> a_prim = a.to_primitive_element()
>>> a_prim.minpoly.as_poly().as_expr(x)
x**2 - 2
we obtain an :py:class:`~.AlgebraicNumber` whose ``minpoly`` is that of
the number itself.
Parameters
==========
radicals : boolean, optional (default=True)
If ``True``, then we will try to return an
:py:class:`~.AlgebraicNumber` whose ``root`` is an expression
in radicals. If that is not possible (or if *radicals* is
``False``), ``root`` will be a :py:class:`~.ComplexRootOf`.
Returns
=======
AlgebraicNumber
See Also
========
is_primitive_element
"""
if self.is_primitive_element:
return self
m = self.minpoly_of_element()
r = self.to_root(radicals=radicals)
return AlgebraicNumber((m, r))
def minpoly_of_element(self):
r"""
Compute the minimal polynomial for this algebraic number.
Explanation
===========
Recall that we represent an element $\alpha \in \mathbb{Q}(\theta)$.
Our instance attribute ``self.minpoly`` is the minimal polynomial for
our primitive element $\theta$. This method computes the minimal
polynomial for $\alpha$.
"""
if self._own_minpoly is None:
if self.is_primitive_element:
self._own_minpoly = self.minpoly
else:
from sympy.polys.numberfields.minpoly import minpoly
theta = self.primitive_element()
self._own_minpoly = minpoly(self.as_expr(theta), polys=True)
return self._own_minpoly
def to_root(self, radicals=True, minpoly=None):
"""
Convert to an :py:class:`~.Expr` that is not an
:py:class:`~.AlgebraicNumber`, specifically, either a
:py:class:`~.ComplexRootOf`, or, optionally and where possible, an
expression in radicals.
Parameters
==========
radicals : boolean, optional (default=True)
If ``True``, then we will try to return the root as an expression
in radicals. If that is not possible, we will return a
:py:class:`~.ComplexRootOf`.
minpoly : :py:class:`~.Poly`
If the minimal polynomial for `self` has been pre-computed, it can
be passed in order to save time.
"""
if self.is_primitive_element and not isinstance(self.root, AlgebraicNumber):
return self.root
m = minpoly or self.minpoly_of_element()
roots = m.all_roots(radicals=radicals)
if len(roots) == 1:
return roots[0]
ex = self.as_expr()
for b in roots:
if m.same_root(b, ex):
return b
class RationalConstant(Rational):
"""
Abstract base class for rationals with specific behaviors
Derived classes must define class attributes p and q and should probably all
be singletons.
"""
__slots__ = ()
def __new__(cls):
return AtomicExpr.__new__(cls)
class IntegerConstant(Integer):
__slots__ = ()
def __new__(cls):
return AtomicExpr.__new__(cls)
class Zero(IntegerConstant, metaclass=Singleton):
"""The number zero.
Zero is a singleton, and can be accessed by ``S.Zero``
Examples
========
>>> from sympy import S, Integer
>>> Integer(0) is S.Zero
True
>>> 1/S.Zero
zoo
References
==========
.. [1] https://en.wikipedia.org/wiki/Zero
"""
p = 0
q = 1
is_positive = False
is_negative = False
is_zero = True
is_number = True
is_comparable = True
__slots__ = ()
def __getnewargs__(self):
return ()
@staticmethod
def __abs__():
return S.Zero
@staticmethod
def __neg__():
return S.Zero
def _eval_power(self, expt):
if expt.is_extended_positive:
return self
if expt.is_extended_negative:
return S.ComplexInfinity
if expt.is_extended_real is False:
return S.NaN
if expt.is_zero:
return S.One
# infinities are already handled with pos and neg
# tests above; now throw away leading numbers on Mul
# exponent since 0**-x = zoo**x even when x == 0
coeff, terms = expt.as_coeff_Mul()
if coeff.is_negative:
return S.ComplexInfinity**terms
if coeff is not S.One: # there is a Number to discard
return self**terms
def _eval_order(self, *symbols):
# Order(0,x) -> 0
return self
def __bool__(self):
return False
class One(IntegerConstant, metaclass=Singleton):
"""The number one.
One is a singleton, and can be accessed by ``S.One``.
Examples
========
>>> from sympy import S, Integer
>>> Integer(1) is S.One
True
References
==========
.. [1] https://en.wikipedia.org/wiki/1_%28number%29
"""
is_number = True
is_positive = True
p = 1
q = 1
__slots__ = ()
def __getnewargs__(self):
return ()
@staticmethod
def __abs__():
return S.One
@staticmethod
def __neg__():
return S.NegativeOne
def _eval_power(self, expt):
return self
def _eval_order(self, *symbols):
return
@staticmethod
def factors(limit=None, use_trial=True, use_rho=False, use_pm1=False,
verbose=False, visual=False):
if visual:
return S.One
else:
return {}
class NegativeOne(IntegerConstant, metaclass=Singleton):
"""The number negative one.
NegativeOne is a singleton, and can be accessed by ``S.NegativeOne``.
Examples
========
>>> from sympy import S, Integer
>>> Integer(-1) is S.NegativeOne
True
See Also
========
One
References
==========
.. [1] https://en.wikipedia.org/wiki/%E2%88%921_%28number%29
"""
is_number = True
p = -1
q = 1
__slots__ = ()
def __getnewargs__(self):
return ()
@staticmethod
def __abs__():
return S.One
@staticmethod
def __neg__():
return S.One
def _eval_power(self, expt):
if expt.is_odd:
return S.NegativeOne
if expt.is_even:
return S.One
if isinstance(expt, Number):
if isinstance(expt, Float):
return Float(-1.0)**expt
if expt is S.NaN:
return S.NaN
if expt in (S.Infinity, S.NegativeInfinity):
return S.NaN
if expt is S.Half:
return S.ImaginaryUnit
if isinstance(expt, Rational):
if expt.q == 2:
return S.ImaginaryUnit**Integer(expt.p)
i, r = divmod(expt.p, expt.q)
if i:
return self**i*self**Rational(r, expt.q)
return
class Half(RationalConstant, metaclass=Singleton):
"""The rational number 1/2.
Half is a singleton, and can be accessed by ``S.Half``.
Examples
========
>>> from sympy import S, Rational
>>> Rational(1, 2) is S.Half
True
References
==========
.. [1] https://en.wikipedia.org/wiki/One_half
"""
is_number = True
p = 1
q = 2
__slots__ = ()
def __getnewargs__(self):
return ()
@staticmethod
def __abs__():
return S.Half
class Infinity(Number, metaclass=Singleton):
r"""Positive infinite quantity.
Explanation
===========
In real analysis the symbol `\infty` denotes an unbounded
limit: `x\to\infty` means that `x` grows without bound.
Infinity is often used not only to define a limit but as a value
in the affinely extended real number system. Points labeled `+\infty`
and `-\infty` can be added to the topological space of the real numbers,
producing the two-point compactification of the real numbers. Adding
algebraic properties to this gives us the extended real numbers.
Infinity is a singleton, and can be accessed by ``S.Infinity``,
or can be imported as ``oo``.
Examples
========
>>> from sympy import oo, exp, limit, Symbol
>>> 1 + oo
oo
>>> 42/oo
0
>>> x = Symbol('x')
>>> limit(exp(x), x, oo)
oo
See Also
========
NegativeInfinity, NaN
References
==========
.. [1] https://en.wikipedia.org/wiki/Infinity
"""
is_commutative = True
is_number = True
is_complex = False
is_extended_real = True
is_infinite = True
is_comparable = True
is_extended_positive = True
is_prime = False
__slots__ = ()
def __new__(cls):
return AtomicExpr.__new__(cls)
def _latex(self, printer):
return r"\infty"
def _eval_subs(self, old, new):
if self == old:
return new
def _eval_evalf(self, prec=None):
return Float('inf')
def evalf(self, prec=None, **options):
return self._eval_evalf(prec)
@_sympifyit('other', NotImplemented)
def __add__(self, other):
if isinstance(other, Number) and global_parameters.evaluate:
if other in (S.NegativeInfinity, S.NaN):
return S.NaN
return self
return Number.__add__(self, other)
__radd__ = __add__
@_sympifyit('other', NotImplemented)
def __sub__(self, other):
if isinstance(other, Number) and global_parameters.evaluate:
if other in (S.Infinity, S.NaN):
return S.NaN
return self
return Number.__sub__(self, other)
@_sympifyit('other', NotImplemented)
def __rsub__(self, other):
return (-self).__add__(other)
@_sympifyit('other', NotImplemented)
def __mul__(self, other):
if isinstance(other, Number) and global_parameters.evaluate:
if other.is_zero or other is S.NaN:
return S.NaN
if other.is_extended_positive:
return self
return S.NegativeInfinity
return Number.__mul__(self, other)
__rmul__ = __mul__
@_sympifyit('other', NotImplemented)
def __truediv__(self, other):
if isinstance(other, Number) and global_parameters.evaluate:
if other is S.Infinity or \
other is S.NegativeInfinity or \
other is S.NaN:
return S.NaN
if other.is_extended_nonnegative:
return self
return S.NegativeInfinity
return Number.__truediv__(self, other)
def __abs__(self):
return S.Infinity
def __neg__(self):
return S.NegativeInfinity
def _eval_power(self, expt):
"""
``expt`` is symbolic object but not equal to 0 or 1.
================ ======= ==============================
Expression Result Notes
================ ======= ==============================
``oo ** nan`` ``nan``
``oo ** -p`` ``0`` ``p`` is number, ``oo``
================ ======= ==============================
See Also
========
Pow
NaN
NegativeInfinity
"""
if expt.is_extended_positive:
return S.Infinity
if expt.is_extended_negative:
return S.Zero
if expt is S.NaN:
return S.NaN
if expt is S.ComplexInfinity:
return S.NaN
if expt.is_extended_real is False and expt.is_number:
from sympy.functions.elementary.complexes import re
expt_real = re(expt)
if expt_real.is_positive:
return S.ComplexInfinity
if expt_real.is_negative:
return S.Zero
if expt_real.is_zero:
return S.NaN
return self**expt.evalf()
def _as_mpf_val(self, prec):
return mlib.finf
def __hash__(self):
return super().__hash__()
def __eq__(self, other):
return other is S.Infinity or other == float('inf')
def __ne__(self, other):
return other is not S.Infinity and other != float('inf')
__gt__ = Expr.__gt__
__ge__ = Expr.__ge__
__lt__ = Expr.__lt__
__le__ = Expr.__le__
@_sympifyit('other', NotImplemented)
def __mod__(self, other):
if not isinstance(other, Expr):
return NotImplemented
return S.NaN
__rmod__ = __mod__
def floor(self):
return self
def ceiling(self):
return self
oo = S.Infinity
class NegativeInfinity(Number, metaclass=Singleton):
"""Negative infinite quantity.
NegativeInfinity is a singleton, and can be accessed
by ``S.NegativeInfinity``.
See Also
========
Infinity
"""
is_extended_real = True
is_complex = False
is_commutative = True
is_infinite = True
is_comparable = True
is_extended_negative = True
is_number = True
is_prime = False
__slots__ = ()
def __new__(cls):
return AtomicExpr.__new__(cls)
def _latex(self, printer):
return r"-\infty"
def _eval_subs(self, old, new):
if self == old:
return new
def _eval_evalf(self, prec=None):
return Float('-inf')
def evalf(self, prec=None, **options):
return self._eval_evalf(prec)
@_sympifyit('other', NotImplemented)
def __add__(self, other):
if isinstance(other, Number) and global_parameters.evaluate:
if other in (S.Infinity, S.NaN):
return S.NaN
return self
return Number.__add__(self, other)
__radd__ = __add__
@_sympifyit('other', NotImplemented)
def __sub__(self, other):
if isinstance(other, Number) and global_parameters.evaluate:
if other in (S.NegativeInfinity, S.NaN):
return S.NaN
return self
return Number.__sub__(self, other)
@_sympifyit('other', NotImplemented)
def __rsub__(self, other):
return (-self).__add__(other)
@_sympifyit('other', NotImplemented)
def __mul__(self, other):
if isinstance(other, Number) and global_parameters.evaluate:
if other.is_zero or other is S.NaN:
return S.NaN
if other.is_extended_positive:
return self
return S.Infinity
return Number.__mul__(self, other)
__rmul__ = __mul__
@_sympifyit('other', NotImplemented)
def __truediv__(self, other):
if isinstance(other, Number) and global_parameters.evaluate:
if other is S.Infinity or \
other is S.NegativeInfinity or \
other is S.NaN:
return S.NaN
if other.is_extended_nonnegative:
return self
return S.Infinity
return Number.__truediv__(self, other)
def __abs__(self):
return S.Infinity
def __neg__(self):
return S.Infinity
def _eval_power(self, expt):
"""
``expt`` is symbolic object but not equal to 0 or 1.
================ ======= ==============================
Expression Result Notes
================ ======= ==============================
``(-oo) ** nan`` ``nan``
``(-oo) ** oo`` ``nan``
``(-oo) ** -oo`` ``nan``
``(-oo) ** e`` ``oo`` ``e`` is positive even integer
``(-oo) ** o`` ``-oo`` ``o`` is positive odd integer
================ ======= ==============================
See Also
========
Infinity
Pow
NaN
"""
if expt.is_number:
if expt is S.NaN or \
expt is S.Infinity or \
expt is S.NegativeInfinity:
return S.NaN
if isinstance(expt, Integer) and expt.is_extended_positive:
if expt.is_odd:
return S.NegativeInfinity
else:
return S.Infinity
inf_part = S.Infinity**expt
s_part = S.NegativeOne**expt
if inf_part == 0 and s_part.is_finite:
return inf_part
if (inf_part is S.ComplexInfinity and
s_part.is_finite and not s_part.is_zero):
return S.ComplexInfinity
return s_part*inf_part
def _as_mpf_val(self, prec):
return mlib.fninf
def __hash__(self):
return super().__hash__()
def __eq__(self, other):
return other is S.NegativeInfinity or other == float('-inf')
def __ne__(self, other):
return other is not S.NegativeInfinity and other != float('-inf')
__gt__ = Expr.__gt__
__ge__ = Expr.__ge__
__lt__ = Expr.__lt__
__le__ = Expr.__le__
@_sympifyit('other', NotImplemented)
def __mod__(self, other):
if not isinstance(other, Expr):
return NotImplemented
return S.NaN
__rmod__ = __mod__
def floor(self):
return self
def ceiling(self):
return self
def as_powers_dict(self):
return {S.NegativeOne: 1, S.Infinity: 1}
class NaN(Number, metaclass=Singleton):
"""
Not a Number.
Explanation
===========
This serves as a place holder for numeric values that are indeterminate.
Most operations on NaN, produce another NaN. Most indeterminate forms,
such as ``0/0`` or ``oo - oo` produce NaN. Two exceptions are ``0**0``
and ``oo**0``, which all produce ``1`` (this is consistent with Python's
float).
NaN is loosely related to floating point nan, which is defined in the
IEEE 754 floating point standard, and corresponds to the Python
``float('nan')``. Differences are noted below.
NaN is mathematically not equal to anything else, even NaN itself. This
explains the initially counter-intuitive results with ``Eq`` and ``==`` in
the examples below.
NaN is not comparable so inequalities raise a TypeError. This is in
contrast with floating point nan where all inequalities are false.
NaN is a singleton, and can be accessed by ``S.NaN``, or can be imported
as ``nan``.
Examples
========
>>> from sympy import nan, S, oo, Eq
>>> nan is S.NaN
True
>>> oo - oo
nan
>>> nan + 1
nan
>>> Eq(nan, nan) # mathematical equality
False
>>> nan == nan # structural equality
True
References
==========
.. [1] https://en.wikipedia.org/wiki/NaN
"""
is_commutative = True
is_extended_real = None
is_real = None
is_rational = None
is_algebraic = None
is_transcendental = None
is_integer = None
is_comparable = False
is_finite = None
is_zero = None
is_prime = None
is_positive = None
is_negative = None
is_number = True
__slots__ = ()
def __new__(cls):
return AtomicExpr.__new__(cls)
def _latex(self, printer):
return r"\text{NaN}"
def __neg__(self):
return self
@_sympifyit('other', NotImplemented)
def __add__(self, other):
return self
@_sympifyit('other', NotImplemented)
def __sub__(self, other):
return self
@_sympifyit('other', NotImplemented)
def __mul__(self, other):
return self
@_sympifyit('other', NotImplemented)
def __truediv__(self, other):
return self
def floor(self):
return self
def ceiling(self):
return self
def _as_mpf_val(self, prec):
return _mpf_nan
def __hash__(self):
return super().__hash__()
def __eq__(self, other):
# NaN is structurally equal to another NaN
return other is S.NaN
def __ne__(self, other):
return other is not S.NaN
# Expr will _sympify and raise TypeError
__gt__ = Expr.__gt__
__ge__ = Expr.__ge__
__lt__ = Expr.__lt__
__le__ = Expr.__le__
nan = S.NaN
@dispatch(NaN, Expr) # type:ignore
def _eval_is_eq(a, b): # noqa:F811
return False
class ComplexInfinity(AtomicExpr, metaclass=Singleton):
r"""Complex infinity.
Explanation
===========
In complex analysis the symbol `\tilde\infty`, called "complex
infinity", represents a quantity with infinite magnitude, but
undetermined complex phase.
ComplexInfinity is a singleton, and can be accessed by
``S.ComplexInfinity``, or can be imported as ``zoo``.
Examples
========
>>> from sympy import zoo
>>> zoo + 42
zoo
>>> 42/zoo
0
>>> zoo + zoo
nan
>>> zoo*zoo
zoo
See Also
========
Infinity
"""
is_commutative = True
is_infinite = True
is_number = True
is_prime = False
is_complex = False
is_extended_real = False
kind = NumberKind
__slots__ = ()
def __new__(cls):
return AtomicExpr.__new__(cls)
def _latex(self, printer):
return r"\tilde{\infty}"
@staticmethod
def __abs__():
return S.Infinity
def floor(self):
return self
def ceiling(self):
return self
@staticmethod
def __neg__():
return S.ComplexInfinity
def _eval_power(self, expt):
if expt is S.ComplexInfinity:
return S.NaN
if isinstance(expt, Number):
if expt.is_zero:
return S.NaN
else:
if expt.is_positive:
return S.ComplexInfinity
else:
return S.Zero
zoo = S.ComplexInfinity
class NumberSymbol(AtomicExpr):
is_commutative = True
is_finite = True
is_number = True
__slots__ = ()
is_NumberSymbol = True
kind = NumberKind
def __new__(cls):
return AtomicExpr.__new__(cls)
def approximation(self, number_cls):
""" Return an interval with number_cls endpoints
that contains the value of NumberSymbol.
If not implemented, then return None.
"""
def _eval_evalf(self, prec):
return Float._new(self._as_mpf_val(prec), prec)
def __eq__(self, other):
try:
other = _sympify(other)
except SympifyError:
return NotImplemented
if self is other:
return True
if other.is_Number and self.is_irrational:
return False
return False # NumberSymbol != non-(Number|self)
def __ne__(self, other):
return not self == other
def __le__(self, other):
if self is other:
return S.true
return Expr.__le__(self, other)
def __ge__(self, other):
if self is other:
return S.true
return Expr.__ge__(self, other)
def __int__(self):
# subclass with appropriate return value
raise NotImplementedError
def __hash__(self):
return super().__hash__()
class Exp1(NumberSymbol, metaclass=Singleton):
r"""The `e` constant.
Explanation
===========
The transcendental number `e = 2.718281828\ldots` is the base of the
natural logarithm and of the exponential function, `e = \exp(1)`.
Sometimes called Euler's number or Napier's constant.
Exp1 is a singleton, and can be accessed by ``S.Exp1``,
or can be imported as ``E``.
Examples
========
>>> from sympy import exp, log, E
>>> E is exp(1)
True
>>> log(E)
1
References
==========
.. [1] https://en.wikipedia.org/wiki/E_%28mathematical_constant%29
"""
is_real = True
is_positive = True
is_negative = False # XXX Forces is_negative/is_nonnegative
is_irrational = True
is_number = True
is_algebraic = False
is_transcendental = True
__slots__ = ()
def _latex(self, printer):
return r"e"
@staticmethod
def __abs__():
return S.Exp1
def __int__(self):
return 2
def _as_mpf_val(self, prec):
return mpf_e(prec)
def approximation_interval(self, number_cls):
if issubclass(number_cls, Integer):
return (Integer(2), Integer(3))
elif issubclass(number_cls, Rational):
pass
def _eval_power(self, expt):
if global_parameters.exp_is_pow:
return self._eval_power_exp_is_pow(expt)
else:
from sympy.functions.elementary.exponential import exp
return exp(expt)
def _eval_power_exp_is_pow(self, arg):
if arg.is_Number:
if arg is oo:
return oo
elif arg == -oo:
return S.Zero
from sympy.functions.elementary.exponential import log
if isinstance(arg, log):
return arg.args[0]
# don't autoexpand Pow or Mul (see the issue 3351):
elif not arg.is_Add:
Ioo = I*oo
if arg in [Ioo, -Ioo]:
return nan
coeff = arg.coeff(pi*I)
if coeff:
if (2*coeff).is_integer:
if coeff.is_even:
return S.One
elif coeff.is_odd:
return S.NegativeOne
elif (coeff + S.Half).is_even:
return -I
elif (coeff + S.Half).is_odd:
return I
elif coeff.is_Rational:
ncoeff = coeff % 2 # restrict to [0, 2pi)
if ncoeff > 1: # restrict to (-pi, pi]
ncoeff -= 2
if ncoeff != coeff:
return S.Exp1**(ncoeff*S.Pi*S.ImaginaryUnit)
# Warning: code in risch.py will be very sensitive to changes
# in this (see DifferentialExtension).
# look for a single log factor
coeff, terms = arg.as_coeff_Mul()
# but it can't be multiplied by oo
if coeff in (oo, -oo):
return
coeffs, log_term = [coeff], None
for term in Mul.make_args(terms):
if isinstance(term, log):
if log_term is None:
log_term = term.args[0]
else:
return
elif term.is_comparable:
coeffs.append(term)
else:
return
return log_term**Mul(*coeffs) if log_term else None
elif arg.is_Add:
out = []
add = []
argchanged = False
for a in arg.args:
if a is S.One:
add.append(a)
continue
newa = self**a
if isinstance(newa, Pow) and newa.base is self:
if newa.exp != a:
add.append(newa.exp)
argchanged = True
else:
add.append(a)
else:
out.append(newa)
if out or argchanged:
return Mul(*out)*Pow(self, Add(*add), evaluate=False)
elif arg.is_Matrix:
return arg.exp()
def _eval_rewrite_as_sin(self, **kwargs):
from sympy.functions.elementary.trigonometric import sin
return sin(I + S.Pi/2) - I*sin(I)
def _eval_rewrite_as_cos(self, **kwargs):
from sympy.functions.elementary.trigonometric import cos
return cos(I) + I*cos(I + S.Pi/2)
E = S.Exp1
class Pi(NumberSymbol, metaclass=Singleton):
r"""The `\pi` constant.
Explanation
===========
The transcendental number `\pi = 3.141592654\ldots` represents the ratio
of a circle's circumference to its diameter, the area of the unit circle,
the half-period of trigonometric functions, and many other things
in mathematics.
Pi is a singleton, and can be accessed by ``S.Pi``, or can
be imported as ``pi``.
Examples
========
>>> from sympy import S, pi, oo, sin, exp, integrate, Symbol
>>> S.Pi
pi
>>> pi > 3
True
>>> pi.is_irrational
True
>>> x = Symbol('x')
>>> sin(x + 2*pi)
sin(x)
>>> integrate(exp(-x**2), (x, -oo, oo))
sqrt(pi)
References
==========
.. [1] https://en.wikipedia.org/wiki/Pi
"""
is_real = True
is_positive = True
is_negative = False
is_irrational = True
is_number = True
is_algebraic = False
is_transcendental = True
__slots__ = ()
def _latex(self, printer):
return r"\pi"
@staticmethod
def __abs__():
return S.Pi
def __int__(self):
return 3
def _as_mpf_val(self, prec):
return mpf_pi(prec)
def approximation_interval(self, number_cls):
if issubclass(number_cls, Integer):
return (Integer(3), Integer(4))
elif issubclass(number_cls, Rational):
return (Rational(223, 71, 1), Rational(22, 7, 1))
pi = S.Pi
class GoldenRatio(NumberSymbol, metaclass=Singleton):
r"""The golden ratio, `\phi`.
Explanation
===========
`\phi = \frac{1 + \sqrt{5}}{2}` is an algebraic number. Two quantities
are in the golden ratio if their ratio is the same as the ratio of
their sum to the larger of the two quantities, i.e. their maximum.
GoldenRatio is a singleton, and can be accessed by ``S.GoldenRatio``.
Examples
========
>>> from sympy import S
>>> S.GoldenRatio > 1
True
>>> S.GoldenRatio.expand(func=True)
1/2 + sqrt(5)/2
>>> S.GoldenRatio.is_irrational
True
References
==========
.. [1] https://en.wikipedia.org/wiki/Golden_ratio
"""
is_real = True
is_positive = True
is_negative = False
is_irrational = True
is_number = True
is_algebraic = True
is_transcendental = False
__slots__ = ()
def _latex(self, printer):
return r"\phi"
def __int__(self):
return 1
def _as_mpf_val(self, prec):
# XXX track down why this has to be increased
rv = mlib.from_man_exp(phi_fixed(prec + 10), -prec - 10)
return mpf_norm(rv, prec)
def _eval_expand_func(self, **hints):
from sympy.functions.elementary.miscellaneous import sqrt
return S.Half + S.Half*sqrt(5)
def approximation_interval(self, number_cls):
if issubclass(number_cls, Integer):
return (S.One, Rational(2))
elif issubclass(number_cls, Rational):
pass
_eval_rewrite_as_sqrt = _eval_expand_func
class TribonacciConstant(NumberSymbol, metaclass=Singleton):
r"""The tribonacci constant.
Explanation
===========
The tribonacci numbers are like the Fibonacci numbers, but instead
of starting with two predetermined terms, the sequence starts with
three predetermined terms and each term afterwards is the sum of the
preceding three terms.
The tribonacci constant is the ratio toward which adjacent tribonacci
numbers tend. It is a root of the polynomial `x^3 - x^2 - x - 1 = 0`,
and also satisfies the equation `x + x^{-3} = 2`.
TribonacciConstant is a singleton, and can be accessed
by ``S.TribonacciConstant``.
Examples
========
>>> from sympy import S
>>> S.TribonacciConstant > 1
True
>>> S.TribonacciConstant.expand(func=True)
1/3 + (19 - 3*sqrt(33))**(1/3)/3 + (3*sqrt(33) + 19)**(1/3)/3
>>> S.TribonacciConstant.is_irrational
True
>>> S.TribonacciConstant.n(20)
1.8392867552141611326
References
==========
.. [1] https://en.wikipedia.org/wiki/Generalizations_of_Fibonacci_numbers#Tribonacci_numbers
"""
is_real = True
is_positive = True
is_negative = False
is_irrational = True
is_number = True
is_algebraic = True
is_transcendental = False
__slots__ = ()
def _latex(self, printer):
return r"\text{TribonacciConstant}"
def __int__(self):
return 1
def _as_mpf_val(self, prec):
return self._eval_evalf(prec)._mpf_
def _eval_evalf(self, prec):
rv = self._eval_expand_func(function=True)._eval_evalf(prec + 4)
return Float(rv, precision=prec)
def _eval_expand_func(self, **hints):
from sympy.functions.elementary.miscellaneous import cbrt, sqrt
return (1 + cbrt(19 - 3*sqrt(33)) + cbrt(19 + 3*sqrt(33))) / 3
def approximation_interval(self, number_cls):
if issubclass(number_cls, Integer):
return (S.One, Rational(2))
elif issubclass(number_cls, Rational):
pass
_eval_rewrite_as_sqrt = _eval_expand_func
class EulerGamma(NumberSymbol, metaclass=Singleton):
r"""The Euler-Mascheroni constant.
Explanation
===========
`\gamma = 0.5772157\ldots` (also called Euler's constant) is a mathematical
constant recurring in analysis and number theory. It is defined as the
limiting difference between the harmonic series and the
natural logarithm:
.. math:: \gamma = \lim\limits_{n\to\infty}
\left(\sum\limits_{k=1}^n\frac{1}{k} - \ln n\right)
EulerGamma is a singleton, and can be accessed by ``S.EulerGamma``.
Examples
========
>>> from sympy import S
>>> S.EulerGamma.is_irrational
>>> S.EulerGamma > 0
True
>>> S.EulerGamma > 1
False
References
==========
.. [1] https://en.wikipedia.org/wiki/Euler%E2%80%93Mascheroni_constant
"""
is_real = True
is_positive = True
is_negative = False
is_irrational = None
is_number = True
__slots__ = ()
def _latex(self, printer):
return r"\gamma"
def __int__(self):
return 0
def _as_mpf_val(self, prec):
# XXX track down why this has to be increased
v = mlib.libhyper.euler_fixed(prec + 10)
rv = mlib.from_man_exp(v, -prec - 10)
return mpf_norm(rv, prec)
def approximation_interval(self, number_cls):
if issubclass(number_cls, Integer):
return (S.Zero, S.One)
elif issubclass(number_cls, Rational):
return (S.Half, Rational(3, 5, 1))
class Catalan(NumberSymbol, metaclass=Singleton):
r"""Catalan's constant.
Explanation
===========
$G = 0.91596559\ldots$ is given by the infinite series
.. math:: G = \sum_{k=0}^{\infty} \frac{(-1)^k}{(2k+1)^2}
Catalan is a singleton, and can be accessed by ``S.Catalan``.
Examples
========
>>> from sympy import S
>>> S.Catalan.is_irrational
>>> S.Catalan > 0
True
>>> S.Catalan > 1
False
References
==========
.. [1] https://en.wikipedia.org/wiki/Catalan%27s_constant
"""
is_real = True
is_positive = True
is_negative = False
is_irrational = None
is_number = True
__slots__ = ()
def __int__(self):
return 0
def _as_mpf_val(self, prec):
# XXX track down why this has to be increased
v = mlib.catalan_fixed(prec + 10)
rv = mlib.from_man_exp(v, -prec - 10)
return mpf_norm(rv, prec)
def approximation_interval(self, number_cls):
if issubclass(number_cls, Integer):
return (S.Zero, S.One)
elif issubclass(number_cls, Rational):
return (Rational(9, 10, 1), S.One)
def _eval_rewrite_as_Sum(self, k_sym=None, symbols=None, **hints):
if (k_sym is not None) or (symbols is not None):
return self
from .symbol import Dummy
from sympy.concrete.summations import Sum
k = Dummy('k', integer=True, nonnegative=True)
return Sum(S.NegativeOne**k / (2*k+1)**2, (k, 0, S.Infinity))
def _latex(self, printer):
return "G"
class ImaginaryUnit(AtomicExpr, metaclass=Singleton):
r"""The imaginary unit, `i = \sqrt{-1}`.
I is a singleton, and can be accessed by ``S.I``, or can be
imported as ``I``.
Examples
========
>>> from sympy import I, sqrt
>>> sqrt(-1)
I
>>> I*I
-1
>>> 1/I
-I
References
==========
.. [1] https://en.wikipedia.org/wiki/Imaginary_unit
"""
is_commutative = True
is_imaginary = True
is_finite = True
is_number = True
is_algebraic = True
is_transcendental = False
kind = NumberKind
__slots__ = ()
def _latex(self, printer):
return printer._settings['imaginary_unit_latex']
@staticmethod
def __abs__():
return S.One
def _eval_evalf(self, prec):
return self
def _eval_conjugate(self):
return -S.ImaginaryUnit
def _eval_power(self, expt):
"""
b is I = sqrt(-1)
e is symbolic object but not equal to 0, 1
I**r -> (-1)**(r/2) -> exp(r/2*Pi*I) -> sin(Pi*r/2) + cos(Pi*r/2)*I, r is decimal
I**0 mod 4 -> 1
I**1 mod 4 -> I
I**2 mod 4 -> -1
I**3 mod 4 -> -I
"""
if isinstance(expt, Integer):
expt = expt % 4
if expt == 0:
return S.One
elif expt == 1:
return S.ImaginaryUnit
elif expt == 2:
return S.NegativeOne
elif expt == 3:
return -S.ImaginaryUnit
if isinstance(expt, Rational):
i, r = divmod(expt, 2)
rv = Pow(S.ImaginaryUnit, r, evaluate=False)
if i % 2:
return Mul(S.NegativeOne, rv, evaluate=False)
return rv
def as_base_exp(self):
return S.NegativeOne, S.Half
@property
def _mpc_(self):
return (Float(0)._mpf_, Float(1)._mpf_)
I = S.ImaginaryUnit
def int_valued(x):
"""return True only for a literal Number whose internal
representation as a fraction has a denominator of 1,
else False, i.e. integer, with no fractional part.
"""
if isinstance(x, (SYMPY_INTS, int)):
return True
if type(x) is float:
return x.is_integer()
if isinstance(x, Integer):
return True
if isinstance(x, Float):
# x = s*m*2**p; _mpf_ = s,m,e,p
return x._mpf_[2] >= 0
return False # or add new types to recognize
def equal_valued(x, y):
"""Compare expressions treating plain floats as rationals.
Examples
========
>>> from sympy import S, symbols, Rational, Float
>>> from sympy.core.numbers import equal_valued
>>> equal_valued(1, 2)
False
>>> equal_valued(1, 1)
True
In SymPy expressions with Floats compare unequal to corresponding
expressions with rationals:
>>> x = symbols('x')
>>> x**2 == x**2.0
False
However an individual Float compares equal to a Rational:
>>> Rational(1, 2) == Float(0.5)
False
In a future version of SymPy this might change so that Rational and Float
compare unequal. This function provides the behavior currently expected of
``==`` so that it could still be used if the behavior of ``==`` were to
change in future.
>>> equal_valued(1, 1.0) # Float vs Rational
True
>>> equal_valued(S(1).n(3), S(1).n(5)) # Floats of different precision
True
Explanation
===========
In future SymPy verions Float and Rational might compare unequal and floats
with different precisions might compare unequal. In that context a function
is needed that can check if a number is equal to 1 or 0 etc. The idea is
that instead of testing ``if x == 1:`` if we want to accept floats like
``1.0`` as well then the test can be written as ``if equal_valued(x, 1):``
or ``if equal_valued(x, 2):``. Since this function is intended to be used
in situations where one or both operands are expected to be concrete
numbers like 1 or 0 the function does not recurse through the args of any
compound expression to compare any nested floats.
References
==========
.. [1] https://github.com/sympy/sympy/pull/20033
"""
x = _sympify(x)
y = _sympify(y)
# Handle everything except Float/Rational first
if not x.is_Float and not y.is_Float:
return x == y
elif x.is_Float and y.is_Float:
# Compare values without regard for precision
return x._mpf_ == y._mpf_
elif x.is_Float:
x, y = y, x
if not x.is_Rational:
return False
# Now y is Float and x is Rational. A simple approach at this point would
# just be x == Rational(y) but if y has a large exponent creating a
# Rational could be prohibitively expensive.
sign, man, exp, _ = y._mpf_
p, q = x.p, x.q
if sign:
man = -man
if exp == 0:
# y odd integer
return q == 1 and man == p
elif exp > 0:
# y even integer
if q != 1:
return False
if p.bit_length() != man.bit_length() + exp:
return False
return man << exp == p
else:
# y non-integer. Need p == man and q == 2**-exp
if p != man:
return False
neg_exp = -exp
if q.bit_length() - 1 != neg_exp:
return False
return (1 << neg_exp) == q
def all_close(expr1, expr2, rtol=1e-5, atol=1e-8):
"""Return True if expr1 and expr2 are numerically close.
The expressions must have the same structure, but any Rational, Integer, or
Float numbers they contain are compared approximately using rtol and atol.
Any other parts of expressions are compared exactly.
Relative tolerance is measured with respect to expr2 so when used in
testing expr2 should be the expected correct answer.
Examples
========
>>> from sympy import exp
>>> from sympy.abc import x, y
>>> from sympy.core.numbers import all_close
>>> expr1 = 0.1*exp(x - y)
>>> expr2 = exp(x - y)/10
>>> expr1
0.1*exp(x - y)
>>> expr2
exp(x - y)/10
>>> expr1 == expr2
False
>>> all_close(expr1, expr2)
True
"""
NUM_TYPES = (Rational, Float)
def _all_close(expr1, expr2, rtol, atol):
num1 = isinstance(expr1, NUM_TYPES)
num2 = isinstance(expr2, NUM_TYPES)
if num1 != num2:
return False
elif num1:
return bool(abs(expr1 - expr2) <= atol + rtol*abs(expr2))
elif expr1.is_Atom:
return expr1 == expr2
elif expr1.func != expr2.func or len(expr1.args) != len(expr2.args):
return False
elif expr1.is_Add or expr1.is_Mul:
return _all_close_ac(expr1, expr2, rtol, atol)
else:
args = zip(expr1.args, expr2.args)
return all(_all_close(a1, a2, rtol, atol) for a1, a2 in args)
def _all_close_ac(expr1, expr2, rtol, atol):
# Compare expressions with associative commutative operators for
# approximate equality. This could be horribly inefficient for large
# expressions e.g. an Add with many terms.
args2 = list(expr2.args)
for arg1 in expr1.args:
for i, arg2 in enumerate(args2):
if _all_close(arg1, arg2, rtol, atol):
args2.pop(i)
break
else:
return False
return True
return _all_close(_sympify(expr1), _sympify(expr2), rtol, atol)
@dispatch(Tuple, Number) # type:ignore
def _eval_is_eq(self, other): # noqa: F811
return False
def sympify_fractions(f):
return Rational(f.numerator, f.denominator, 1)
_sympy_converter[fractions.Fraction] = sympify_fractions
if gmpy is not None:
def sympify_mpz(x):
return Integer(int(x))
def sympify_mpq(x):
return Rational(int(x.numerator), int(x.denominator))
_sympy_converter[type(gmpy.mpz(1))] = sympify_mpz
_sympy_converter[type(gmpy.mpq(1, 2))] = sympify_mpq
if flint is not None:
def sympify_fmpz(x):
return Integer(int(x))
def sympify_fmpq(x):
return Rational(int(x.numerator), int(x.denominator))
_sympy_converter[type(flint.fmpz(1))] = sympify_fmpz
_sympy_converter[type(flint.fmpq(1, 2))] = sympify_fmpq
def sympify_mpmath(x):
return Expr._from_mpmath(x, x.context.prec)
_sympy_converter[mpnumeric] = sympify_mpmath
def sympify_complex(a):
real, imag = list(map(sympify, (a.real, a.imag)))
return real + S.ImaginaryUnit*imag
_sympy_converter[complex] = sympify_complex
from .power import Pow
from .mul import Mul
Mul.identity = One()
from .add import Add
Add.identity = Zero()
def _register_classes():
numbers.Number.register(Number)
numbers.Real.register(Float)
numbers.Rational.register(Rational)
numbers.Integral.register(Integer)
_register_classes()
_illegal = (S.NaN, S.Infinity, S.NegativeInfinity, S.ComplexInfinity)
PK ]ZZZ�
��a �a sympy/core/operations.pyfrom __future__ import annotations
from operator import attrgetter
from collections import defaultdict
from sympy.utilities.exceptions import sympy_deprecation_warning
from .sympify import _sympify as _sympify_, sympify
from .basic import Basic
from .cache import cacheit
from .sorting import ordered
from .logic import fuzzy_and
from .parameters import global_parameters
from sympy.utilities.iterables import sift
from sympy.multipledispatch.dispatcher import (Dispatcher,
ambiguity_register_error_ignore_dup,
str_signature, RaiseNotImplementedError)
class AssocOp(Basic):
""" Associative operations, can separate noncommutative and
commutative parts.
(a op b) op c == a op (b op c) == a op b op c.
Base class for Add and Mul.
This is an abstract base class, concrete derived classes must define
the attribute `identity`.
.. deprecated:: 1.7
Using arguments that aren't subclasses of :class:`~.Expr` in core
operators (:class:`~.Mul`, :class:`~.Add`, and :class:`~.Pow`) is
deprecated. See :ref:`non-expr-args-deprecated` for details.
Parameters
==========
*args :
Arguments which are operated
evaluate : bool, optional
Evaluate the operation. If not passed, refer to ``global_parameters.evaluate``.
"""
# for performance reason, we don't let is_commutative go to assumptions,
# and keep it right here
__slots__: tuple[str, ...] = ('is_commutative',)
_args_type: type[Basic] | None = None
@cacheit
def __new__(cls, *args, evaluate=None, _sympify=True):
# Allow faster processing by passing ``_sympify=False``, if all arguments
# are already sympified.
if _sympify:
args = list(map(_sympify_, args))
# Disallow non-Expr args in Add/Mul
typ = cls._args_type
if typ is not None:
from .relational import Relational
if any(isinstance(arg, Relational) for arg in args):
raise TypeError("Relational cannot be used in %s" % cls.__name__)
# This should raise TypeError once deprecation period is over:
for arg in args:
if not isinstance(arg, typ):
sympy_deprecation_warning(
f"""
Using non-Expr arguments in {cls.__name__} is deprecated (in this case, one of
the arguments has type {type(arg).__name__!r}).
If you really did intend to use a multiplication or addition operation with
this object, use the * or + operator instead.
""",
deprecated_since_version="1.7",
active_deprecations_target="non-expr-args-deprecated",
stacklevel=4,
)
if evaluate is None:
evaluate = global_parameters.evaluate
if not evaluate:
obj = cls._from_args(args)
obj = cls._exec_constructor_postprocessors(obj)
return obj
args = [a for a in args if a is not cls.identity]
if len(args) == 0:
return cls.identity
if len(args) == 1:
return args[0]
c_part, nc_part, order_symbols = cls.flatten(args)
is_commutative = not nc_part
obj = cls._from_args(c_part + nc_part, is_commutative)
obj = cls._exec_constructor_postprocessors(obj)
if order_symbols is not None:
from sympy.series.order import Order
return Order(obj, *order_symbols)
return obj
@classmethod
def _from_args(cls, args, is_commutative=None):
"""Create new instance with already-processed args.
If the args are not in canonical order, then a non-canonical
result will be returned, so use with caution. The order of
args may change if the sign of the args is changed."""
if len(args) == 0:
return cls.identity
elif len(args) == 1:
return args[0]
obj = super().__new__(cls, *args)
if is_commutative is None:
is_commutative = fuzzy_and(a.is_commutative for a in args)
obj.is_commutative = is_commutative
return obj
def _new_rawargs(self, *args, reeval=True, **kwargs):
"""Create new instance of own class with args exactly as provided by
caller but returning the self class identity if args is empty.
Examples
========
This is handy when we want to optimize things, e.g.
>>> from sympy import Mul, S
>>> from sympy.abc import x, y
>>> e = Mul(3, x, y)
>>> e.args
(3, x, y)
>>> Mul(*e.args[1:])
x*y
>>> e._new_rawargs(*e.args[1:]) # the same as above, but faster
x*y
Note: use this with caution. There is no checking of arguments at
all. This is best used when you are rebuilding an Add or Mul after
simply removing one or more args. If, for example, modifications,
result in extra 1s being inserted they will show up in the result:
>>> m = (x*y)._new_rawargs(S.One, x); m
1*x
>>> m == x
False
>>> m.is_Mul
True
Another issue to be aware of is that the commutativity of the result
is based on the commutativity of self. If you are rebuilding the
terms that came from a commutative object then there will be no
problem, but if self was non-commutative then what you are
rebuilding may now be commutative.
Although this routine tries to do as little as possible with the
input, getting the commutativity right is important, so this level
of safety is enforced: commutativity will always be recomputed if
self is non-commutative and kwarg `reeval=False` has not been
passed.
"""
if reeval and self.is_commutative is False:
is_commutative = None
else:
is_commutative = self.is_commutative
return self._from_args(args, is_commutative)
@classmethod
def flatten(cls, seq):
"""Return seq so that none of the elements are of type `cls`. This is
the vanilla routine that will be used if a class derived from AssocOp
does not define its own flatten routine."""
# apply associativity, no commutativity property is used
new_seq = []
while seq:
o = seq.pop()
if o.__class__ is cls: # classes must match exactly
seq.extend(o.args)
else:
new_seq.append(o)
new_seq.reverse()
# c_part, nc_part, order_symbols
return [], new_seq, None
def _matches_commutative(self, expr, repl_dict=None, old=False):
"""
Matches Add/Mul "pattern" to an expression "expr".
repl_dict ... a dictionary of (wild: expression) pairs, that get
returned with the results
This function is the main workhorse for Add/Mul.
Examples
========
>>> from sympy import symbols, Wild, sin
>>> a = Wild("a")
>>> b = Wild("b")
>>> c = Wild("c")
>>> x, y, z = symbols("x y z")
>>> (a+sin(b)*c)._matches_commutative(x+sin(y)*z)
{a_: x, b_: y, c_: z}
In the example above, "a+sin(b)*c" is the pattern, and "x+sin(y)*z" is
the expression.
The repl_dict contains parts that were already matched. For example
here:
>>> (x+sin(b)*c)._matches_commutative(x+sin(y)*z, repl_dict={a: x})
{a_: x, b_: y, c_: z}
the only function of the repl_dict is to return it in the
result, e.g. if you omit it:
>>> (x+sin(b)*c)._matches_commutative(x+sin(y)*z)
{b_: y, c_: z}
the "a: x" is not returned in the result, but otherwise it is
equivalent.
"""
from .function import _coeff_isneg
# make sure expr is Expr if pattern is Expr
from .expr import Expr
if isinstance(self, Expr) and not isinstance(expr, Expr):
return None
if repl_dict is None:
repl_dict = {}
# handle simple patterns
if self == expr:
return repl_dict
d = self._matches_simple(expr, repl_dict)
if d is not None:
return d
# eliminate exact part from pattern: (2+a+w1+w2).matches(expr) -> (w1+w2).matches(expr-a-2)
from .function import WildFunction
from .symbol import Wild
wild_part, exact_part = sift(self.args, lambda p:
p.has(Wild, WildFunction) and not expr.has(p),
binary=True)
if not exact_part:
wild_part = list(ordered(wild_part))
if self.is_Add:
# in addition to normal ordered keys, impose
# sorting on Muls with leading Number to put
# them in order
wild_part = sorted(wild_part, key=lambda x:
x.args[0] if x.is_Mul and x.args[0].is_Number else
0)
else:
exact = self._new_rawargs(*exact_part)
free = expr.free_symbols
if free and (exact.free_symbols - free):
# there are symbols in the exact part that are not
# in the expr; but if there are no free symbols, let
# the matching continue
return None
newexpr = self._combine_inverse(expr, exact)
if not old and (expr.is_Add or expr.is_Mul):
check = newexpr
if _coeff_isneg(check):
check = -check
if check.count_ops() > expr.count_ops():
return None
newpattern = self._new_rawargs(*wild_part)
return newpattern.matches(newexpr, repl_dict)
# now to real work ;)
i = 0
saw = set()
while expr not in saw:
saw.add(expr)
args = tuple(ordered(self.make_args(expr)))
if self.is_Add and expr.is_Add:
# in addition to normal ordered keys, impose
# sorting on Muls with leading Number to put
# them in order
args = tuple(sorted(args, key=lambda x:
x.args[0] if x.is_Mul and x.args[0].is_Number else
0))
expr_list = (self.identity,) + args
for last_op in reversed(expr_list):
for w in reversed(wild_part):
d1 = w.matches(last_op, repl_dict)
if d1 is not None:
d2 = self.xreplace(d1).matches(expr, d1)
if d2 is not None:
return d2
if i == 0:
if self.is_Mul:
# make e**i look like Mul
if expr.is_Pow and expr.exp.is_Integer:
from .mul import Mul
if expr.exp > 0:
expr = Mul(*[expr.base, expr.base**(expr.exp - 1)], evaluate=False)
else:
expr = Mul(*[1/expr.base, expr.base**(expr.exp + 1)], evaluate=False)
i += 1
continue
elif self.is_Add:
# make i*e look like Add
c, e = expr.as_coeff_Mul()
if abs(c) > 1:
from .add import Add
if c > 0:
expr = Add(*[e, (c - 1)*e], evaluate=False)
else:
expr = Add(*[-e, (c + 1)*e], evaluate=False)
i += 1
continue
# try collection on non-Wild symbols
from sympy.simplify.radsimp import collect
was = expr
did = set()
for w in reversed(wild_part):
c, w = w.as_coeff_mul(Wild)
free = c.free_symbols - did
if free:
did.update(free)
expr = collect(expr, free)
if expr != was:
i += 0
continue
break # if we didn't continue, there is nothing more to do
return
def _has_matcher(self):
"""Helper for .has() that checks for containment of
subexpressions within an expr by using sets of args
of similar nodes, e.g. x + 1 in x + y + 1 checks
to see that {x, 1} & {x, y, 1} == {x, 1}
"""
def _ncsplit(expr):
# this is not the same as args_cnc because here
# we don't assume expr is a Mul -- hence deal with args --
# and always return a set.
cpart, ncpart = sift(expr.args,
lambda arg: arg.is_commutative is True, binary=True)
return set(cpart), ncpart
c, nc = _ncsplit(self)
cls = self.__class__
def is_in(expr):
if isinstance(expr, cls):
if expr == self:
return True
_c, _nc = _ncsplit(expr)
if (c & _c) == c:
if not nc:
return True
elif len(nc) <= len(_nc):
for i in range(len(_nc) - len(nc) + 1):
if _nc[i:i + len(nc)] == nc:
return True
return False
return is_in
def _eval_evalf(self, prec):
"""
Evaluate the parts of self that are numbers; if the whole thing
was a number with no functions it would have been evaluated, but
it wasn't so we must judiciously extract the numbers and reconstruct
the object. This is *not* simply replacing numbers with evaluated
numbers. Numbers should be handled in the largest pure-number
expression as possible. So the code below separates ``self`` into
number and non-number parts and evaluates the number parts and
walks the args of the non-number part recursively (doing the same
thing).
"""
from .add import Add
from .mul import Mul
from .symbol import Symbol
from .function import AppliedUndef
if isinstance(self, (Mul, Add)):
x, tail = self.as_independent(Symbol, AppliedUndef)
# if x is an AssocOp Function then the _evalf below will
# call _eval_evalf (here) so we must break the recursion
if not (tail is self.identity or
isinstance(x, AssocOp) and x.is_Function or
x is self.identity and isinstance(tail, AssocOp)):
# here, we have a number so we just call to _evalf with prec;
# prec is not the same as n, it is the binary precision so
# that's why we don't call to evalf.
x = x._evalf(prec) if x is not self.identity else self.identity
args = []
tail_args = tuple(self.func.make_args(tail))
for a in tail_args:
# here we call to _eval_evalf since we don't know what we
# are dealing with and all other _eval_evalf routines should
# be doing the same thing (i.e. taking binary prec and
# finding the evalf-able args)
newa = a._eval_evalf(prec)
if newa is None:
args.append(a)
else:
args.append(newa)
return self.func(x, *args)
# this is the same as above, but there were no pure-number args to
# deal with
args = []
for a in self.args:
newa = a._eval_evalf(prec)
if newa is None:
args.append(a)
else:
args.append(newa)
return self.func(*args)
@classmethod
def make_args(cls, expr):
"""
Return a sequence of elements `args` such that cls(*args) == expr
Examples
========
>>> from sympy import Symbol, Mul, Add
>>> x, y = map(Symbol, 'xy')
>>> Mul.make_args(x*y)
(x, y)
>>> Add.make_args(x*y)
(x*y,)
>>> set(Add.make_args(x*y + y)) == set([y, x*y])
True
"""
if isinstance(expr, cls):
return expr.args
else:
return (sympify(expr),)
def doit(self, **hints):
if hints.get('deep', True):
terms = [term.doit(**hints) for term in self.args]
else:
terms = self.args
return self.func(*terms, evaluate=True)
class ShortCircuit(Exception):
pass
class LatticeOp(AssocOp):
"""
Join/meet operations of an algebraic lattice[1].
Explanation
===========
These binary operations are associative (op(op(a, b), c) = op(a, op(b, c))),
commutative (op(a, b) = op(b, a)) and idempotent (op(a, a) = op(a) = a).
Common examples are AND, OR, Union, Intersection, max or min. They have an
identity element (op(identity, a) = a) and an absorbing element
conventionally called zero (op(zero, a) = zero).
This is an abstract base class, concrete derived classes must declare
attributes zero and identity. All defining properties are then respected.
Examples
========
>>> from sympy import Integer
>>> from sympy.core.operations import LatticeOp
>>> class my_join(LatticeOp):
... zero = Integer(0)
... identity = Integer(1)
>>> my_join(2, 3) == my_join(3, 2)
True
>>> my_join(2, my_join(3, 4)) == my_join(2, 3, 4)
True
>>> my_join(0, 1, 4, 2, 3, 4)
0
>>> my_join(1, 2)
2
References
==========
.. [1] https://en.wikipedia.org/wiki/Lattice_%28order%29
"""
is_commutative = True
def __new__(cls, *args, **options):
args = (_sympify_(arg) for arg in args)
try:
# /!\ args is a generator and _new_args_filter
# must be careful to handle as such; this
# is done so short-circuiting can be done
# without having to sympify all values
_args = frozenset(cls._new_args_filter(args))
except ShortCircuit:
return sympify(cls.zero)
if not _args:
return sympify(cls.identity)
elif len(_args) == 1:
return set(_args).pop()
else:
# XXX in almost every other case for __new__, *_args is
# passed along, but the expectation here is for _args
obj = super(AssocOp, cls).__new__(cls, *ordered(_args))
obj._argset = _args
return obj
@classmethod
def _new_args_filter(cls, arg_sequence, call_cls=None):
"""Generator filtering args"""
ncls = call_cls or cls
for arg in arg_sequence:
if arg == ncls.zero:
raise ShortCircuit(arg)
elif arg == ncls.identity:
continue
elif arg.func == ncls:
yield from arg.args
else:
yield arg
@classmethod
def make_args(cls, expr):
"""
Return a set of args such that cls(*arg_set) == expr.
"""
if isinstance(expr, cls):
return expr._argset
else:
return frozenset([sympify(expr)])
class AssocOpDispatcher:
"""
Handler dispatcher for associative operators
.. notes::
This approach is experimental, and can be replaced or deleted in the future.
See https://github.com/sympy/sympy/pull/19463.
Explanation
===========
If arguments of different types are passed, the classes which handle the operation for each type
are collected. Then, a class which performs the operation is selected by recursive binary dispatching.
Dispatching relation can be registered by ``register_handlerclass`` method.
Priority registration is unordered. You cannot make ``A*B`` and ``B*A`` refer to
different handler classes. All logic dealing with the order of arguments must be implemented
in the handler class.
Examples
========
>>> from sympy import Add, Expr, Symbol
>>> from sympy.core.add import add
>>> class NewExpr(Expr):
... @property
... def _add_handler(self):
... return NewAdd
>>> class NewAdd(NewExpr, Add):
... pass
>>> add.register_handlerclass((Add, NewAdd), NewAdd)
>>> a, b = Symbol('a'), NewExpr()
>>> add(a, b) == NewAdd(a, b)
True
"""
def __init__(self, name, doc=None):
self.name = name
self.doc = doc
self.handlerattr = "_%s_handler" % name
self._handlergetter = attrgetter(self.handlerattr)
self._dispatcher = Dispatcher(name)
def __repr__(self):
return "<dispatched %s>" % self.name
def register_handlerclass(self, classes, typ, on_ambiguity=ambiguity_register_error_ignore_dup):
"""
Register the handler class for two classes, in both straight and reversed order.
Paramteters
===========
classes : tuple of two types
Classes who are compared with each other.
typ:
Class which is registered to represent *cls1* and *cls2*.
Handler method of *self* must be implemented in this class.
"""
if not len(classes) == 2:
raise RuntimeError(
"Only binary dispatch is supported, but got %s types: <%s>." % (
len(classes), str_signature(classes)
))
if len(set(classes)) == 1:
raise RuntimeError(
"Duplicate types <%s> cannot be dispatched." % str_signature(classes)
)
self._dispatcher.add(tuple(classes), typ, on_ambiguity=on_ambiguity)
self._dispatcher.add(tuple(reversed(classes)), typ, on_ambiguity=on_ambiguity)
@cacheit
def __call__(self, *args, _sympify=True, **kwargs):
"""
Parameters
==========
*args :
Arguments which are operated
"""
if _sympify:
args = tuple(map(_sympify_, args))
handlers = frozenset(map(self._handlergetter, args))
# no need to sympify again
return self.dispatch(handlers)(*args, _sympify=False, **kwargs)
@cacheit
def dispatch(self, handlers):
"""
Select the handler class, and return its handler method.
"""
# Quick exit for the case where all handlers are same
if len(handlers) == 1:
h, = handlers
if not isinstance(h, type):
raise RuntimeError("Handler {!r} is not a type.".format(h))
return h
# Recursively select with registered binary priority
for i, typ in enumerate(handlers):
if not isinstance(typ, type):
raise RuntimeError("Handler {!r} is not a type.".format(typ))
if i == 0:
handler = typ
else:
prev_handler = handler
handler = self._dispatcher.dispatch(prev_handler, typ)
if not isinstance(handler, type):
raise RuntimeError(
"Dispatcher for {!r} and {!r} must return a type, but got {!r}".format(
prev_handler, typ, handler
))
# return handler class
return handler
@property
def __doc__(self):
docs = [
"Multiply dispatched associative operator: %s" % self.name,
"Note that support for this is experimental, see the docs for :class:`AssocOpDispatcher` for details"
]
if self.doc:
docs.append(self.doc)
s = "Registered handler classes\n"
s += '=' * len(s)
docs.append(s)
amb_sigs = []
typ_sigs = defaultdict(list)
for sigs in self._dispatcher.ordering[::-1]:
key = self._dispatcher.funcs[sigs]
typ_sigs[key].append(sigs)
for typ, sigs in typ_sigs.items():
sigs_str = ', '.join('<%s>' % str_signature(sig) for sig in sigs)
if isinstance(typ, RaiseNotImplementedError):
amb_sigs.append(sigs_str)
continue
s = 'Inputs: %s\n' % sigs_str
s += '-' * len(s) + '\n'
s += typ.__name__
docs.append(s)
if amb_sigs:
s = "Ambiguous handler classes\n"
s += '=' * len(s)
docs.append(s)
s = '\n'.join(amb_sigs)
docs.append(s)
return '\n\n'.join(docs)
PK ]ZZZ�߯ sympy/core/parameters.py"""Thread-safe global parameters"""
from .cache import clear_cache
from contextlib import contextmanager
from threading import local
class _global_parameters(local):
"""
Thread-local global parameters.
Explanation
===========
This class generates thread-local container for SymPy's global parameters.
Every global parameters must be passed as keyword argument when generating
its instance.
A variable, `global_parameters` is provided as default instance for this class.
WARNING! Although the global parameters are thread-local, SymPy's cache is not
by now.
This may lead to undesired result in multi-threading operations.
Examples
========
>>> from sympy.abc import x
>>> from sympy.core.cache import clear_cache
>>> from sympy.core.parameters import global_parameters as gp
>>> gp.evaluate
True
>>> x+x
2*x
>>> log = []
>>> def f():
... clear_cache()
... gp.evaluate = False
... log.append(x+x)
... clear_cache()
>>> import threading
>>> thread = threading.Thread(target=f)
>>> thread.start()
>>> thread.join()
>>> print(log)
[x + x]
>>> gp.evaluate
True
>>> x+x
2*x
References
==========
.. [1] https://docs.python.org/3/library/threading.html
"""
def __init__(self, **kwargs):
self.__dict__.update(kwargs)
def __setattr__(self, name, value):
if getattr(self, name) != value:
clear_cache()
return super().__setattr__(name, value)
global_parameters = _global_parameters(evaluate=True, distribute=True, exp_is_pow=False)
class evaluate:
""" Control automatic evaluation
Explanation
===========
This context manager controls whether or not all SymPy functions evaluate
by default.
Note that much of SymPy expects evaluated expressions. This functionality
is experimental and is unlikely to function as intended on large
expressions.
Examples
========
>>> from sympy import evaluate
>>> from sympy.abc import x
>>> print(x + x)
2*x
>>> with evaluate(False):
... print(x + x)
x + x
"""
def __init__(self, x):
self.x = x
self.old = []
def __enter__(self):
self.old.append(global_parameters.evaluate)
global_parameters.evaluate = self.x
def __exit__(self, exc_type, exc_val, exc_tb):
global_parameters.evaluate = self.old.pop()
@contextmanager
def distribute(x):
""" Control automatic distribution of Number over Add
Explanation
===========
This context manager controls whether or not Mul distribute Number over
Add. Plan is to avoid distributing Number over Add in all of sympy. Once
that is done, this contextmanager will be removed.
Examples
========
>>> from sympy.abc import x
>>> from sympy.core.parameters import distribute
>>> print(2*(x + 1))
2*x + 2
>>> with distribute(False):
... print(2*(x + 1))
2*(x + 1)
"""
old = global_parameters.distribute
try:
global_parameters.distribute = x
yield
finally:
global_parameters.distribute = old
@contextmanager
def _exp_is_pow(x):
"""
Control whether `e^x` should be represented as ``exp(x)`` or a ``Pow(E, x)``.
Examples
========
>>> from sympy import exp
>>> from sympy.abc import x
>>> from sympy.core.parameters import _exp_is_pow
>>> with _exp_is_pow(True): print(type(exp(x)))
<class 'sympy.core.power.Pow'>
>>> with _exp_is_pow(False): print(type(exp(x)))
exp
"""
old = global_parameters.exp_is_pow
clear_cache()
try:
global_parameters.exp_is_pow = x
yield
finally:
clear_cache()
global_parameters.exp_is_pow = old
PK ]ZZZ�-�� sympy/core/power.pyfrom __future__ import annotations
from typing import Callable
from itertools import product
from .sympify import _sympify
from .cache import cacheit
from .singleton import S
from .expr import Expr
from .evalf import PrecisionExhausted
from .function import (expand_complex, expand_multinomial,
expand_mul, _mexpand, PoleError)
from .logic import fuzzy_bool, fuzzy_not, fuzzy_and, fuzzy_or
from .parameters import global_parameters
from .relational import is_gt, is_lt
from .kind import NumberKind, UndefinedKind
from sympy.utilities.iterables import sift
from sympy.utilities.exceptions import sympy_deprecation_warning
from sympy.utilities.misc import as_int
from sympy.multipledispatch import Dispatcher
class Pow(Expr):
"""
Defines the expression x**y as "x raised to a power y"
.. deprecated:: 1.7
Using arguments that aren't subclasses of :class:`~.Expr` in core
operators (:class:`~.Mul`, :class:`~.Add`, and :class:`~.Pow`) is
deprecated. See :ref:`non-expr-args-deprecated` for details.
Singleton definitions involving (0, 1, -1, oo, -oo, I, -I):
+--------------+---------+-----------------------------------------------+
| expr | value | reason |
+==============+=========+===============================================+
| z**0 | 1 | Although arguments over 0**0 exist, see [2]. |
+--------------+---------+-----------------------------------------------+
| z**1 | z | |
+--------------+---------+-----------------------------------------------+
| (-oo)**(-1) | 0 | |
+--------------+---------+-----------------------------------------------+
| (-1)**-1 | -1 | |
+--------------+---------+-----------------------------------------------+
| S.Zero**-1 | zoo | This is not strictly true, as 0**-1 may be |
| | | undefined, but is convenient in some contexts |
| | | where the base is assumed to be positive. |
+--------------+---------+-----------------------------------------------+
| 1**-1 | 1 | |
+--------------+---------+-----------------------------------------------+
| oo**-1 | 0 | |
+--------------+---------+-----------------------------------------------+
| 0**oo | 0 | Because for all complex numbers z near |
| | | 0, z**oo -> 0. |
+--------------+---------+-----------------------------------------------+
| 0**-oo | zoo | This is not strictly true, as 0**oo may be |
| | | oscillating between positive and negative |
| | | values or rotating in the complex plane. |
| | | It is convenient, however, when the base |
| | | is positive. |
+--------------+---------+-----------------------------------------------+
| 1**oo | nan | Because there are various cases where |
| 1**-oo | | lim(x(t),t)=1, lim(y(t),t)=oo (or -oo), |
| | | but lim( x(t)**y(t), t) != 1. See [3]. |
+--------------+---------+-----------------------------------------------+
| b**zoo | nan | Because b**z has no limit as z -> zoo |
+--------------+---------+-----------------------------------------------+
| (-1)**oo | nan | Because of oscillations in the limit. |
| (-1)**(-oo) | | |
+--------------+---------+-----------------------------------------------+
| oo**oo | oo | |
+--------------+---------+-----------------------------------------------+
| oo**-oo | 0 | |
+--------------+---------+-----------------------------------------------+
| (-oo)**oo | nan | |
| (-oo)**-oo | | |
+--------------+---------+-----------------------------------------------+
| oo**I | nan | oo**e could probably be best thought of as |
| (-oo)**I | | the limit of x**e for real x as x tends to |
| | | oo. If e is I, then the limit does not exist |
| | | and nan is used to indicate that. |
+--------------+---------+-----------------------------------------------+
| oo**(1+I) | zoo | If the real part of e is positive, then the |
| (-oo)**(1+I) | | limit of abs(x**e) is oo. So the limit value |
| | | is zoo. |
+--------------+---------+-----------------------------------------------+
| oo**(-1+I) | 0 | If the real part of e is negative, then the |
| -oo**(-1+I) | | limit is 0. |
+--------------+---------+-----------------------------------------------+
Because symbolic computations are more flexible than floating point
calculations and we prefer to never return an incorrect answer,
we choose not to conform to all IEEE 754 conventions. This helps
us avoid extra test-case code in the calculation of limits.
See Also
========
sympy.core.numbers.Infinity
sympy.core.numbers.NegativeInfinity
sympy.core.numbers.NaN
References
==========
.. [1] https://en.wikipedia.org/wiki/Exponentiation
.. [2] https://en.wikipedia.org/wiki/Zero_to_the_power_of_zero
.. [3] https://en.wikipedia.org/wiki/Indeterminate_forms
"""
is_Pow = True
__slots__ = ('is_commutative',)
args: tuple[Expr, Expr]
_args: tuple[Expr, Expr]
@cacheit
def __new__(cls, b, e, evaluate=None):
if evaluate is None:
evaluate = global_parameters.evaluate
b = _sympify(b)
e = _sympify(e)
# XXX: This can be removed when non-Expr args are disallowed rather
# than deprecated.
from .relational import Relational
if isinstance(b, Relational) or isinstance(e, Relational):
raise TypeError('Relational cannot be used in Pow')
# XXX: This should raise TypeError once deprecation period is over:
for arg in [b, e]:
if not isinstance(arg, Expr):
sympy_deprecation_warning(
f"""
Using non-Expr arguments in Pow is deprecated (in this case, one of the
arguments is of type {type(arg).__name__!r}).
If you really did intend to construct a power with this base, use the **
operator instead.""",
deprecated_since_version="1.7",
active_deprecations_target="non-expr-args-deprecated",
stacklevel=4,
)
if evaluate:
if e is S.ComplexInfinity:
return S.NaN
if e is S.Infinity:
if is_gt(b, S.One):
return S.Infinity
if is_gt(b, S.NegativeOne) and is_lt(b, S.One):
return S.Zero
if is_lt(b, S.NegativeOne):
if b.is_finite:
return S.ComplexInfinity
if b.is_finite is False:
return S.NaN
if e is S.Zero:
return S.One
elif e is S.One:
return b
elif e == -1 and not b:
return S.ComplexInfinity
elif e.__class__.__name__ == "AccumulationBounds":
if b == S.Exp1:
from sympy.calculus.accumulationbounds import AccumBounds
return AccumBounds(Pow(b, e.min), Pow(b, e.max))
# autosimplification if base is a number and exp odd/even
# if base is Number then the base will end up positive; we
# do not do this with arbitrary expressions since symbolic
# cancellation might occur as in (x - 1)/(1 - x) -> -1. If
# we returned Piecewise((-1, Ne(x, 1))) for such cases then
# we could do this...but we don't
elif (e.is_Symbol and e.is_integer or e.is_Integer
) and (b.is_number and b.is_Mul or b.is_Number
) and b.could_extract_minus_sign():
if e.is_even:
b = -b
elif e.is_odd:
return -Pow(-b, e)
if S.NaN in (b, e): # XXX S.NaN**x -> S.NaN under assumption that x != 0
return S.NaN
elif b is S.One:
if abs(e).is_infinite:
return S.NaN
return S.One
else:
# recognize base as E
from sympy.functions.elementary.exponential import exp_polar
if not e.is_Atom and b is not S.Exp1 and not isinstance(b, exp_polar):
from .exprtools import factor_terms
from sympy.functions.elementary.exponential import log
from sympy.simplify.radsimp import fraction
c, ex = factor_terms(e, sign=False).as_coeff_Mul()
num, den = fraction(ex)
if isinstance(den, log) and den.args[0] == b:
return S.Exp1**(c*num)
elif den.is_Add:
from sympy.functions.elementary.complexes import sign, im
s = sign(im(b))
if s.is_Number and s and den == \
log(-factor_terms(b, sign=False)) + s*S.ImaginaryUnit*S.Pi:
return S.Exp1**(c*num)
obj = b._eval_power(e)
if obj is not None:
return obj
obj = Expr.__new__(cls, b, e)
obj = cls._exec_constructor_postprocessors(obj)
if not isinstance(obj, Pow):
return obj
obj.is_commutative = (b.is_commutative and e.is_commutative)
return obj
def inverse(self, argindex=1):
if self.base == S.Exp1:
from sympy.functions.elementary.exponential import log
return log
return None
@property
def base(self) -> Expr:
return self._args[0]
@property
def exp(self) -> Expr:
return self._args[1]
@property
def kind(self):
if self.exp.kind is NumberKind:
return self.base.kind
else:
return UndefinedKind
@classmethod
def class_key(cls):
return 3, 2, cls.__name__
def _eval_refine(self, assumptions):
from sympy.assumptions.ask import ask, Q
b, e = self.as_base_exp()
if ask(Q.integer(e), assumptions) and b.could_extract_minus_sign():
if ask(Q.even(e), assumptions):
return Pow(-b, e)
elif ask(Q.odd(e), assumptions):
return -Pow(-b, e)
def _eval_power(self, other):
b, e = self.as_base_exp()
if b is S.NaN:
return (b**e)**other # let __new__ handle it
s = None
if other.is_integer:
s = 1
elif b.is_polar: # e.g. exp_polar, besselj, var('p', polar=True)...
s = 1
elif e.is_extended_real is not None:
from sympy.functions.elementary.complexes import arg, im, re, sign
from sympy.functions.elementary.exponential import exp, log
from sympy.functions.elementary.integers import floor
# helper functions ===========================
def _half(e):
"""Return True if the exponent has a literal 2 as the
denominator, else None."""
if getattr(e, 'q', None) == 2:
return True
n, d = e.as_numer_denom()
if n.is_integer and d == 2:
return True
def _n2(e):
"""Return ``e`` evaluated to a Number with 2 significant
digits, else None."""
try:
rv = e.evalf(2, strict=True)
if rv.is_Number:
return rv
except PrecisionExhausted:
pass
# ===================================================
if e.is_extended_real:
# we need _half(other) with constant floor or
# floor(S.Half - e*arg(b)/2/pi) == 0
# handle -1 as special case
if e == -1:
# floor arg. is 1/2 + arg(b)/2/pi
if _half(other):
if b.is_negative is True:
return S.NegativeOne**other*Pow(-b, e*other)
elif b.is_negative is False: # XXX ok if im(b) != 0?
return Pow(b, -other)
elif e.is_even:
if b.is_extended_real:
b = abs(b)
if b.is_imaginary:
b = abs(im(b))*S.ImaginaryUnit
if (abs(e) < 1) == True or e == 1:
s = 1 # floor = 0
elif b.is_extended_nonnegative:
s = 1 # floor = 0
elif re(b).is_extended_nonnegative and (abs(e) < 2) == True:
s = 1 # floor = 0
elif _half(other):
s = exp(2*S.Pi*S.ImaginaryUnit*other*floor(
S.Half - e*arg(b)/(2*S.Pi)))
if s.is_extended_real and _n2(sign(s) - s) == 0:
s = sign(s)
else:
s = None
else:
# e.is_extended_real is False requires:
# _half(other) with constant floor or
# floor(S.Half - im(e*log(b))/2/pi) == 0
try:
s = exp(2*S.ImaginaryUnit*S.Pi*other*
floor(S.Half - im(e*log(b))/2/S.Pi))
# be careful to test that s is -1 or 1 b/c sign(I) == I:
# so check that s is real
if s.is_extended_real and _n2(sign(s) - s) == 0:
s = sign(s)
else:
s = None
except PrecisionExhausted:
s = None
if s is not None:
return s*Pow(b, e*other)
def _eval_Mod(self, q):
r"""A dispatched function to compute `b^e \bmod q`, dispatched
by ``Mod``.
Notes
=====
Algorithms:
1. For unevaluated integer power, use built-in ``pow`` function
with 3 arguments, if powers are not too large wrt base.
2. For very large powers, use totient reduction if $e \ge \log(m)$.
Bound on m, is for safe factorization memory wise i.e. $m^{1/4}$.
For pollard-rho to be faster than built-in pow $\log(e) > m^{1/4}$
check is added.
3. For any unevaluated power found in `b` or `e`, the step 2
will be recursed down to the base and the exponent
such that the $b \bmod q$ becomes the new base and
$\phi(q) + e \bmod \phi(q)$ becomes the new exponent, and then
the computation for the reduced expression can be done.
"""
base, exp = self.base, self.exp
if exp.is_integer and exp.is_positive:
if q.is_integer and base % q == 0:
return S.Zero
from sympy.functions.combinatorial.numbers import totient
if base.is_Integer and exp.is_Integer and q.is_Integer:
b, e, m = int(base), int(exp), int(q)
mb = m.bit_length()
if mb <= 80 and e >= mb and e.bit_length()**4 >= m:
phi = int(totient(m))
return Integer(pow(b, phi + e%phi, m))
return Integer(pow(b, e, m))
from .mod import Mod
if isinstance(base, Pow) and base.is_integer and base.is_number:
base = Mod(base, q)
return Mod(Pow(base, exp, evaluate=False), q)
if isinstance(exp, Pow) and exp.is_integer and exp.is_number:
bit_length = int(q).bit_length()
# XXX Mod-Pow actually attempts to do a hanging evaluation
# if this dispatched function returns None.
# May need some fixes in the dispatcher itself.
if bit_length <= 80:
phi = totient(q)
exp = phi + Mod(exp, phi)
return Mod(Pow(base, exp, evaluate=False), q)
def _eval_is_even(self):
if self.exp.is_integer and self.exp.is_positive:
return self.base.is_even
def _eval_is_negative(self):
ext_neg = Pow._eval_is_extended_negative(self)
if ext_neg is True:
return self.is_finite
return ext_neg
def _eval_is_extended_positive(self):
if self.base == self.exp:
if self.base.is_extended_nonnegative:
return True
elif self.base.is_positive:
if self.exp.is_real:
return True
elif self.base.is_extended_negative:
if self.exp.is_even:
return True
if self.exp.is_odd:
return False
elif self.base.is_zero:
if self.exp.is_extended_real:
return self.exp.is_zero
elif self.base.is_extended_nonpositive:
if self.exp.is_odd:
return False
elif self.base.is_imaginary:
if self.exp.is_integer:
m = self.exp % 4
if m.is_zero:
return True
if m.is_integer and m.is_zero is False:
return False
if self.exp.is_imaginary:
from sympy.functions.elementary.exponential import log
return log(self.base).is_imaginary
def _eval_is_extended_negative(self):
if self.exp is S.Half:
if self.base.is_complex or self.base.is_extended_real:
return False
if self.base.is_extended_negative:
if self.exp.is_odd and self.base.is_finite:
return True
if self.exp.is_even:
return False
elif self.base.is_extended_positive:
if self.exp.is_extended_real:
return False
elif self.base.is_zero:
if self.exp.is_extended_real:
return False
elif self.base.is_extended_nonnegative:
if self.exp.is_extended_nonnegative:
return False
elif self.base.is_extended_nonpositive:
if self.exp.is_even:
return False
elif self.base.is_extended_real:
if self.exp.is_even:
return False
def _eval_is_zero(self):
if self.base.is_zero:
if self.exp.is_extended_positive:
return True
elif self.exp.is_extended_nonpositive:
return False
elif self.base == S.Exp1:
return self.exp is S.NegativeInfinity
elif self.base.is_zero is False:
if self.base.is_finite and self.exp.is_finite:
return False
elif self.exp.is_negative:
return self.base.is_infinite
elif self.exp.is_nonnegative:
return False
elif self.exp.is_infinite and self.exp.is_extended_real:
if (1 - abs(self.base)).is_extended_positive:
return self.exp.is_extended_positive
elif (1 - abs(self.base)).is_extended_negative:
return self.exp.is_extended_negative
elif self.base.is_finite and self.exp.is_negative:
# when self.base.is_zero is None
return False
def _eval_is_integer(self):
b, e = self.args
if b.is_rational:
if b.is_integer is False and e.is_positive:
return False # rat**nonneg
if b.is_integer and e.is_integer:
if b is S.NegativeOne:
return True
if e.is_nonnegative or e.is_positive:
return True
if b.is_integer and e.is_negative and (e.is_finite or e.is_integer):
if fuzzy_not((b - 1).is_zero) and fuzzy_not((b + 1).is_zero):
return False
if b.is_Number and e.is_Number:
check = self.func(*self.args)
return check.is_Integer
if e.is_negative and b.is_positive and (b - 1).is_positive:
return False
if e.is_negative and b.is_negative and (b + 1).is_negative:
return False
def _eval_is_extended_real(self):
if self.base is S.Exp1:
if self.exp.is_extended_real:
return True
elif self.exp.is_imaginary:
return (2*S.ImaginaryUnit*self.exp/S.Pi).is_even
from sympy.functions.elementary.exponential import log, exp
real_b = self.base.is_extended_real
if real_b is None:
if self.base.func == exp and self.base.exp.is_imaginary:
return self.exp.is_imaginary
if self.base.func == Pow and self.base.base is S.Exp1 and self.base.exp.is_imaginary:
return self.exp.is_imaginary
return
real_e = self.exp.is_extended_real
if real_e is None:
return
if real_b and real_e:
if self.base.is_extended_positive:
return True
elif self.base.is_extended_nonnegative and self.exp.is_extended_nonnegative:
return True
elif self.exp.is_integer and self.base.is_extended_nonzero:
return True
elif self.exp.is_integer and self.exp.is_nonnegative:
return True
elif self.base.is_extended_negative:
if self.exp.is_Rational:
return False
if real_e and self.exp.is_extended_negative and self.base.is_zero is False:
return Pow(self.base, -self.exp).is_extended_real
im_b = self.base.is_imaginary
im_e = self.exp.is_imaginary
if im_b:
if self.exp.is_integer:
if self.exp.is_even:
return True
elif self.exp.is_odd:
return False
elif im_e and log(self.base).is_imaginary:
return True
elif self.exp.is_Add:
c, a = self.exp.as_coeff_Add()
if c and c.is_Integer:
return Mul(
self.base**c, self.base**a, evaluate=False).is_extended_real
elif self.base in (-S.ImaginaryUnit, S.ImaginaryUnit):
if (self.exp/2).is_integer is False:
return False
if real_b and im_e:
if self.base is S.NegativeOne:
return True
c = self.exp.coeff(S.ImaginaryUnit)
if c:
if self.base.is_rational and c.is_rational:
if self.base.is_nonzero and (self.base - 1).is_nonzero and c.is_nonzero:
return False
ok = (c*log(self.base)/S.Pi).is_integer
if ok is not None:
return ok
if real_b is False and real_e: # we already know it's not imag
if isinstance(self.exp, Rational) and self.exp.p == 1:
return False
from sympy.functions.elementary.complexes import arg
i = arg(self.base)*self.exp/S.Pi
if i.is_complex: # finite
return i.is_integer
def _eval_is_complex(self):
if self.base == S.Exp1:
return fuzzy_or([self.exp.is_complex, self.exp.is_extended_negative])
if all(a.is_complex for a in self.args) and self._eval_is_finite():
return True
def _eval_is_imaginary(self):
if self.base.is_commutative is False:
return False
if self.base.is_imaginary:
if self.exp.is_integer:
odd = self.exp.is_odd
if odd is not None:
return odd
return
if self.base == S.Exp1:
f = 2 * self.exp / (S.Pi*S.ImaginaryUnit)
# exp(pi*integer) = 1 or -1, so not imaginary
if f.is_even:
return False
# exp(pi*integer + pi/2) = I or -I, so it is imaginary
if f.is_odd:
return True
return None
if self.exp.is_imaginary:
from sympy.functions.elementary.exponential import log
imlog = log(self.base).is_imaginary
if imlog is not None:
return False # I**i -> real; (2*I)**i -> complex ==> not imaginary
if self.base.is_extended_real and self.exp.is_extended_real:
if self.base.is_positive:
return False
else:
rat = self.exp.is_rational
if not rat:
return rat
if self.exp.is_integer:
return False
else:
half = (2*self.exp).is_integer
if half:
return self.base.is_negative
return half
if self.base.is_extended_real is False: # we already know it's not imag
from sympy.functions.elementary.complexes import arg
i = arg(self.base)*self.exp/S.Pi
isodd = (2*i).is_odd
if isodd is not None:
return isodd
def _eval_is_odd(self):
if self.exp.is_integer:
if self.exp.is_positive:
return self.base.is_odd
elif self.exp.is_nonnegative and self.base.is_odd:
return True
elif self.base is S.NegativeOne:
return True
def _eval_is_finite(self):
if self.exp.is_negative:
if self.base.is_zero:
return False
if self.base.is_infinite or self.base.is_nonzero:
return True
c1 = self.base.is_finite
if c1 is None:
return
c2 = self.exp.is_finite
if c2 is None:
return
if c1 and c2:
if self.exp.is_nonnegative or fuzzy_not(self.base.is_zero):
return True
def _eval_is_prime(self):
'''
An integer raised to the n(>=2)-th power cannot be a prime.
'''
if self.base.is_integer and self.exp.is_integer and (self.exp - 1).is_positive:
return False
def _eval_is_composite(self):
"""
A power is composite if both base and exponent are greater than 1
"""
if (self.base.is_integer and self.exp.is_integer and
((self.base - 1).is_positive and (self.exp - 1).is_positive or
(self.base + 1).is_negative and self.exp.is_positive and self.exp.is_even)):
return True
def _eval_is_polar(self):
return self.base.is_polar
def _eval_subs(self, old, new):
from sympy.calculus.accumulationbounds import AccumBounds
if isinstance(self.exp, AccumBounds):
b = self.base.subs(old, new)
e = self.exp.subs(old, new)
if isinstance(e, AccumBounds):
return e.__rpow__(b)
return self.func(b, e)
from sympy.functions.elementary.exponential import exp, log
def _check(ct1, ct2, old):
"""Return (bool, pow, remainder_pow) where, if bool is True, then the
exponent of Pow `old` will combine with `pow` so the substitution
is valid, otherwise bool will be False.
For noncommutative objects, `pow` will be an integer, and a factor
`Pow(old.base, remainder_pow)` needs to be included. If there is
no such factor, None is returned. For commutative objects,
remainder_pow is always None.
cti are the coefficient and terms of an exponent of self or old
In this _eval_subs routine a change like (b**(2*x)).subs(b**x, y)
will give y**2 since (b**x)**2 == b**(2*x); if that equality does
not hold then the substitution should not occur so `bool` will be
False.
"""
coeff1, terms1 = ct1
coeff2, terms2 = ct2
if terms1 == terms2:
if old.is_commutative:
# Allow fractional powers for commutative objects
pow = coeff1/coeff2
try:
as_int(pow, strict=False)
combines = True
except ValueError:
b, e = old.as_base_exp()
# These conditions ensure that (b**e)**f == b**(e*f) for any f
combines = b.is_positive and e.is_real or b.is_nonnegative and e.is_nonnegative
return combines, pow, None
else:
# With noncommutative symbols, substitute only integer powers
if not isinstance(terms1, tuple):
terms1 = (terms1,)
if not all(term.is_integer for term in terms1):
return False, None, None
try:
# Round pow toward zero
pow, remainder = divmod(as_int(coeff1), as_int(coeff2))
if pow < 0 and remainder != 0:
pow += 1
remainder -= as_int(coeff2)
if remainder == 0:
remainder_pow = None
else:
remainder_pow = Mul(remainder, *terms1)
return True, pow, remainder_pow
except ValueError:
# Can't substitute
pass
return False, None, None
if old == self.base or (old == exp and self.base == S.Exp1):
if new.is_Function and isinstance(new, Callable):
return new(self.exp._subs(old, new))
else:
return new**self.exp._subs(old, new)
# issue 10829: (4**x - 3*y + 2).subs(2**x, y) -> y**2 - 3*y + 2
if isinstance(old, self.func) and self.exp == old.exp:
l = log(self.base, old.base)
if l.is_Number:
return Pow(new, l)
if isinstance(old, self.func) and self.base == old.base:
if self.exp.is_Add is False:
ct1 = self.exp.as_independent(Symbol, as_Add=False)
ct2 = old.exp.as_independent(Symbol, as_Add=False)
ok, pow, remainder_pow = _check(ct1, ct2, old)
if ok:
# issue 5180: (x**(6*y)).subs(x**(3*y),z)->z**2
result = self.func(new, pow)
if remainder_pow is not None:
result = Mul(result, Pow(old.base, remainder_pow))
return result
else: # b**(6*x + a).subs(b**(3*x), y) -> y**2 * b**a
# exp(exp(x) + exp(x**2)).subs(exp(exp(x)), w) -> w * exp(exp(x**2))
oarg = old.exp
new_l = []
o_al = []
ct2 = oarg.as_coeff_mul()
for a in self.exp.args:
newa = a._subs(old, new)
ct1 = newa.as_coeff_mul()
ok, pow, remainder_pow = _check(ct1, ct2, old)
if ok:
new_l.append(new**pow)
if remainder_pow is not None:
o_al.append(remainder_pow)
continue
elif not old.is_commutative and not newa.is_integer:
# If any term in the exponent is non-integer,
# we do not do any substitutions in the noncommutative case
return
o_al.append(newa)
if new_l:
expo = Add(*o_al)
new_l.append(Pow(self.base, expo, evaluate=False) if expo != 1 else self.base)
return Mul(*new_l)
if (isinstance(old, exp) or (old.is_Pow and old.base is S.Exp1)) and self.exp.is_extended_real and self.base.is_positive:
ct1 = old.exp.as_independent(Symbol, as_Add=False)
ct2 = (self.exp*log(self.base)).as_independent(
Symbol, as_Add=False)
ok, pow, remainder_pow = _check(ct1, ct2, old)
if ok:
result = self.func(new, pow) # (2**x).subs(exp(x*log(2)), z) -> z
if remainder_pow is not None:
result = Mul(result, Pow(old.base, remainder_pow))
return result
def as_base_exp(self):
"""Return base and exp of self.
Explanation
===========
If base a Rational less than 1, then return 1/Rational, -exp.
If this extra processing is not needed, the base and exp
properties will give the raw arguments.
Examples
========
>>> from sympy import Pow, S
>>> p = Pow(S.Half, 2, evaluate=False)
>>> p.as_base_exp()
(2, -2)
>>> p.args
(1/2, 2)
>>> p.base, p.exp
(1/2, 2)
"""
b, e = self.args
if b.is_Rational and b.p < b.q and b.p > 0:
return 1/b, -e
return b, e
def _eval_adjoint(self):
from sympy.functions.elementary.complexes import adjoint
i, p = self.exp.is_integer, self.base.is_positive
if i:
return adjoint(self.base)**self.exp
if p:
return self.base**adjoint(self.exp)
if i is False and p is False:
expanded = expand_complex(self)
if expanded != self:
return adjoint(expanded)
def _eval_conjugate(self):
from sympy.functions.elementary.complexes import conjugate as c
i, p = self.exp.is_integer, self.base.is_positive
if i:
return c(self.base)**self.exp
if p:
return self.base**c(self.exp)
if i is False and p is False:
expanded = expand_complex(self)
if expanded != self:
return c(expanded)
if self.is_extended_real:
return self
def _eval_transpose(self):
from sympy.functions.elementary.complexes import transpose
if self.base == S.Exp1:
return self.func(S.Exp1, self.exp.transpose())
i, p = self.exp.is_integer, (self.base.is_complex or self.base.is_infinite)
if p:
return self.base**self.exp
if i:
return transpose(self.base)**self.exp
if i is False and p is False:
expanded = expand_complex(self)
if expanded != self:
return transpose(expanded)
def _eval_expand_power_exp(self, **hints):
"""a**(n + m) -> a**n*a**m"""
b = self.base
e = self.exp
if b == S.Exp1:
from sympy.concrete.summations import Sum
if isinstance(e, Sum) and e.is_commutative:
from sympy.concrete.products import Product
return Product(self.func(b, e.function), *e.limits)
if e.is_Add and (hints.get('force', False) or
b.is_zero is False or e._all_nonneg_or_nonppos()):
if e.is_commutative:
return Mul(*[self.func(b, x) for x in e.args])
if b.is_commutative:
c, nc = sift(e.args, lambda x: x.is_commutative, binary=True)
if c:
return Mul(*[self.func(b, x) for x in c]
)*b**Add._from_args(nc)
return self
def _eval_expand_power_base(self, **hints):
"""(a*b)**n -> a**n * b**n"""
force = hints.get('force', False)
b = self.base
e = self.exp
if not b.is_Mul:
return self
cargs, nc = b.args_cnc(split_1=False)
# expand each term - this is top-level-only
# expansion but we have to watch out for things
# that don't have an _eval_expand method
if nc:
nc = [i._eval_expand_power_base(**hints)
if hasattr(i, '_eval_expand_power_base') else i
for i in nc]
if e.is_Integer:
if e.is_positive:
rv = Mul(*nc*e)
else:
rv = Mul(*[i**-1 for i in nc[::-1]]*-e)
if cargs:
rv *= Mul(*cargs)**e
return rv
if not cargs:
return self.func(Mul(*nc), e, evaluate=False)
nc = [Mul(*nc)]
# sift the commutative bases
other, maybe_real = sift(cargs, lambda x: x.is_extended_real is False,
binary=True)
def pred(x):
if x is S.ImaginaryUnit:
return S.ImaginaryUnit
polar = x.is_polar
if polar:
return True
if polar is None:
return fuzzy_bool(x.is_extended_nonnegative)
sifted = sift(maybe_real, pred)
nonneg = sifted[True]
other += sifted[None]
neg = sifted[False]
imag = sifted[S.ImaginaryUnit]
if imag:
I = S.ImaginaryUnit
i = len(imag) % 4
if i == 0:
pass
elif i == 1:
other.append(I)
elif i == 2:
if neg:
nonn = -neg.pop()
if nonn is not S.One:
nonneg.append(nonn)
else:
neg.append(S.NegativeOne)
else:
if neg:
nonn = -neg.pop()
if nonn is not S.One:
nonneg.append(nonn)
else:
neg.append(S.NegativeOne)
other.append(I)
del imag
# bring out the bases that can be separated from the base
if force or e.is_integer:
# treat all commutatives the same and put nc in other
cargs = nonneg + neg + other
other = nc
else:
# this is just like what is happening automatically, except
# that now we are doing it for an arbitrary exponent for which
# no automatic expansion is done
assert not e.is_Integer
# handle negatives by making them all positive and putting
# the residual -1 in other
if len(neg) > 1:
o = S.One
if not other and neg[0].is_Number:
o *= neg.pop(0)
if len(neg) % 2:
o = -o
for n in neg:
nonneg.append(-n)
if o is not S.One:
other.append(o)
elif neg and other:
if neg[0].is_Number and neg[0] is not S.NegativeOne:
other.append(S.NegativeOne)
nonneg.append(-neg[0])
else:
other.extend(neg)
else:
other.extend(neg)
del neg
cargs = nonneg
other += nc
rv = S.One
if cargs:
if e.is_Rational:
npow, cargs = sift(cargs, lambda x: x.is_Pow and
x.exp.is_Rational and x.base.is_number,
binary=True)
rv = Mul(*[self.func(b.func(*b.args), e) for b in npow])
rv *= Mul(*[self.func(b, e, evaluate=False) for b in cargs])
if other:
rv *= self.func(Mul(*other), e, evaluate=False)
return rv
def _eval_expand_multinomial(self, **hints):
"""(a + b + ..)**n -> a**n + n*a**(n-1)*b + .., n is nonzero integer"""
base, exp = self.args
result = self
if exp.is_Rational and exp.p > 0 and base.is_Add:
if not exp.is_Integer:
n = Integer(exp.p // exp.q)
if not n:
return result
else:
radical, result = self.func(base, exp - n), []
expanded_base_n = self.func(base, n)
if expanded_base_n.is_Pow:
expanded_base_n = \
expanded_base_n._eval_expand_multinomial()
for term in Add.make_args(expanded_base_n):
result.append(term*radical)
return Add(*result)
n = int(exp)
if base.is_commutative:
order_terms, other_terms = [], []
for b in base.args:
if b.is_Order:
order_terms.append(b)
else:
other_terms.append(b)
if order_terms:
# (f(x) + O(x^n))^m -> f(x)^m + m*f(x)^{m-1} *O(x^n)
f = Add(*other_terms)
o = Add(*order_terms)
if n == 2:
return expand_multinomial(f**n, deep=False) + n*f*o
else:
g = expand_multinomial(f**(n - 1), deep=False)
return expand_mul(f*g, deep=False) + n*g*o
if base.is_number:
# Efficiently expand expressions of the form (a + b*I)**n
# where 'a' and 'b' are real numbers and 'n' is integer.
a, b = base.as_real_imag()
if a.is_Rational and b.is_Rational:
if not a.is_Integer:
if not b.is_Integer:
k = self.func(a.q * b.q, n)
a, b = a.p*b.q, a.q*b.p
else:
k = self.func(a.q, n)
a, b = a.p, a.q*b
elif not b.is_Integer:
k = self.func(b.q, n)
a, b = a*b.q, b.p
else:
k = 1
a, b, c, d = int(a), int(b), 1, 0
while n:
if n & 1:
c, d = a*c - b*d, b*c + a*d
n -= 1
a, b = a*a - b*b, 2*a*b
n //= 2
I = S.ImaginaryUnit
if k == 1:
return c + I*d
else:
return Integer(c)/k + I*d/k
p = other_terms
# (x + y)**3 -> x**3 + 3*x**2*y + 3*x*y**2 + y**3
# in this particular example:
# p = [x,y]; n = 3
# so now it's easy to get the correct result -- we get the
# coefficients first:
from sympy.ntheory.multinomial import multinomial_coefficients
from sympy.polys.polyutils import basic_from_dict
expansion_dict = multinomial_coefficients(len(p), n)
# in our example: {(3, 0): 1, (1, 2): 3, (0, 3): 1, (2, 1): 3}
# and now construct the expression.
return basic_from_dict(expansion_dict, *p)
else:
if n == 2:
return Add(*[f*g for f in base.args for g in base.args])
else:
multi = (base**(n - 1))._eval_expand_multinomial()
if multi.is_Add:
return Add(*[f*g for f in base.args
for g in multi.args])
else:
# XXX can this ever happen if base was an Add?
return Add(*[f*multi for f in base.args])
elif (exp.is_Rational and exp.p < 0 and base.is_Add and
abs(exp.p) > exp.q):
return 1 / self.func(base, -exp)._eval_expand_multinomial()
elif exp.is_Add and base.is_Number and (hints.get('force', False) or
base.is_zero is False or exp._all_nonneg_or_nonppos()):
# a + b a b
# n --> n n, where n, a, b are Numbers
# XXX should be in expand_power_exp?
coeff, tail = [], []
for term in exp.args:
if term.is_Number:
coeff.append(self.func(base, term))
else:
tail.append(term)
return Mul(*(coeff + [self.func(base, Add._from_args(tail))]))
else:
return result
def as_real_imag(self, deep=True, **hints):
if self.exp.is_Integer:
from sympy.polys.polytools import poly
exp = self.exp
re_e, im_e = self.base.as_real_imag(deep=deep)
if not im_e:
return self, S.Zero
a, b = symbols('a b', cls=Dummy)
if exp >= 0:
if re_e.is_Number and im_e.is_Number:
# We can be more efficient in this case
expr = expand_multinomial(self.base**exp)
if expr != self:
return expr.as_real_imag()
expr = poly(
(a + b)**exp) # a = re, b = im; expr = (a + b*I)**exp
else:
mag = re_e**2 + im_e**2
re_e, im_e = re_e/mag, -im_e/mag
if re_e.is_Number and im_e.is_Number:
# We can be more efficient in this case
expr = expand_multinomial((re_e + im_e*S.ImaginaryUnit)**-exp)
if expr != self:
return expr.as_real_imag()
expr = poly((a + b)**-exp)
# Terms with even b powers will be real
r = [i for i in expr.terms() if not i[0][1] % 2]
re_part = Add(*[cc*a**aa*b**bb for (aa, bb), cc in r])
# Terms with odd b powers will be imaginary
r = [i for i in expr.terms() if i[0][1] % 4 == 1]
im_part1 = Add(*[cc*a**aa*b**bb for (aa, bb), cc in r])
r = [i for i in expr.terms() if i[0][1] % 4 == 3]
im_part3 = Add(*[cc*a**aa*b**bb for (aa, bb), cc in r])
return (re_part.subs({a: re_e, b: S.ImaginaryUnit*im_e}),
im_part1.subs({a: re_e, b: im_e}) + im_part3.subs({a: re_e, b: -im_e}))
from sympy.functions.elementary.trigonometric import atan2, cos, sin
if self.exp.is_Rational:
re_e, im_e = self.base.as_real_imag(deep=deep)
if im_e.is_zero and self.exp is S.Half:
if re_e.is_extended_nonnegative:
return self, S.Zero
if re_e.is_extended_nonpositive:
return S.Zero, (-self.base)**self.exp
# XXX: This is not totally correct since for x**(p/q) with
# x being imaginary there are actually q roots, but
# only a single one is returned from here.
r = self.func(self.func(re_e, 2) + self.func(im_e, 2), S.Half)
t = atan2(im_e, re_e)
rp, tp = self.func(r, self.exp), t*self.exp
return rp*cos(tp), rp*sin(tp)
elif self.base is S.Exp1:
from sympy.functions.elementary.exponential import exp
re_e, im_e = self.exp.as_real_imag()
if deep:
re_e = re_e.expand(deep, **hints)
im_e = im_e.expand(deep, **hints)
c, s = cos(im_e), sin(im_e)
return exp(re_e)*c, exp(re_e)*s
else:
from sympy.functions.elementary.complexes import im, re
if deep:
hints['complex'] = False
expanded = self.expand(deep, **hints)
if hints.get('ignore') == expanded:
return None
else:
return (re(expanded), im(expanded))
else:
return re(self), im(self)
def _eval_derivative(self, s):
from sympy.functions.elementary.exponential import log
dbase = self.base.diff(s)
dexp = self.exp.diff(s)
return self * (dexp * log(self.base) + dbase * self.exp/self.base)
def _eval_evalf(self, prec):
base, exp = self.as_base_exp()
if base == S.Exp1:
# Use mpmath function associated to class "exp":
from sympy.functions.elementary.exponential import exp as exp_function
return exp_function(self.exp, evaluate=False)._eval_evalf(prec)
base = base._evalf(prec)
if not exp.is_Integer:
exp = exp._evalf(prec)
if exp.is_negative and base.is_number and base.is_extended_real is False:
base = base.conjugate() / (base * base.conjugate())._evalf(prec)
exp = -exp
return self.func(base, exp).expand()
return self.func(base, exp)
def _eval_is_polynomial(self, syms):
if self.exp.has(*syms):
return False
if self.base.has(*syms):
return bool(self.base._eval_is_polynomial(syms) and
self.exp.is_Integer and (self.exp >= 0))
else:
return True
def _eval_is_rational(self):
# The evaluation of self.func below can be very expensive in the case
# of integer**integer if the exponent is large. We should try to exit
# before that if possible:
if (self.exp.is_integer and self.base.is_rational
and fuzzy_not(fuzzy_and([self.exp.is_negative, self.base.is_zero]))):
return True
p = self.func(*self.as_base_exp()) # in case it's unevaluated
if not p.is_Pow:
return p.is_rational
b, e = p.as_base_exp()
if e.is_Rational and b.is_Rational:
# we didn't check that e is not an Integer
# because Rational**Integer autosimplifies
return False
if e.is_integer:
if b.is_rational:
if fuzzy_not(b.is_zero) or e.is_nonnegative:
return True
if b == e: # always rational, even for 0**0
return True
elif b.is_irrational:
return e.is_zero
if b is S.Exp1:
if e.is_rational and e.is_nonzero:
return False
def _eval_is_algebraic(self):
def _is_one(expr):
try:
return (expr - 1).is_zero
except ValueError:
# when the operation is not allowed
return False
if self.base.is_zero or _is_one(self.base):
return True
elif self.base is S.Exp1:
s = self.func(*self.args)
if s.func == self.func:
if self.exp.is_nonzero:
if self.exp.is_algebraic:
return False
elif (self.exp/S.Pi).is_rational:
return False
elif (self.exp/(S.ImaginaryUnit*S.Pi)).is_rational:
return True
else:
return s.is_algebraic
elif self.exp.is_rational:
if self.base.is_algebraic is False:
return self.exp.is_zero
if self.base.is_zero is False:
if self.exp.is_nonzero:
return self.base.is_algebraic
elif self.base.is_algebraic:
return True
if self.exp.is_positive:
return self.base.is_algebraic
elif self.base.is_algebraic and self.exp.is_algebraic:
if ((fuzzy_not(self.base.is_zero)
and fuzzy_not(_is_one(self.base)))
or self.base.is_integer is False
or self.base.is_irrational):
return self.exp.is_rational
def _eval_is_rational_function(self, syms):
if self.exp.has(*syms):
return False
if self.base.has(*syms):
return self.base._eval_is_rational_function(syms) and \
self.exp.is_Integer
else:
return True
def _eval_is_meromorphic(self, x, a):
# f**g is meromorphic if g is an integer and f is meromorphic.
# E**(log(f)*g) is meromorphic if log(f)*g is meromorphic
# and finite.
base_merom = self.base._eval_is_meromorphic(x, a)
exp_integer = self.exp.is_Integer
if exp_integer:
return base_merom
exp_merom = self.exp._eval_is_meromorphic(x, a)
if base_merom is False:
# f**g = E**(log(f)*g) may be meromorphic if the
# singularities of log(f) and g cancel each other,
# for example, if g = 1/log(f). Hence,
return False if exp_merom else None
elif base_merom is None:
return None
b = self.base.subs(x, a)
# b is extended complex as base is meromorphic.
# log(base) is finite and meromorphic when b != 0, zoo.
b_zero = b.is_zero
if b_zero:
log_defined = False
else:
log_defined = fuzzy_and((b.is_finite, fuzzy_not(b_zero)))
if log_defined is False: # zero or pole of base
return exp_integer # False or None
elif log_defined is None:
return None
if not exp_merom:
return exp_merom # False or None
return self.exp.subs(x, a).is_finite
def _eval_is_algebraic_expr(self, syms):
if self.exp.has(*syms):
return False
if self.base.has(*syms):
return self.base._eval_is_algebraic_expr(syms) and \
self.exp.is_Rational
else:
return True
def _eval_rewrite_as_exp(self, base, expo, **kwargs):
from sympy.functions.elementary.exponential import exp, log
if base.is_zero or base.has(exp) or expo.has(exp):
return base**expo
evaluate = expo.has(Symbol)
if base.has(Symbol):
# delay evaluation if expo is non symbolic
# (as exp(x*log(5)) automatically reduces to x**5)
if global_parameters.exp_is_pow:
return Pow(S.Exp1, log(base)*expo, evaluate=evaluate)
else:
return exp(log(base)*expo, evaluate=evaluate)
else:
from sympy.functions.elementary.complexes import arg, Abs
return exp((log(Abs(base)) + S.ImaginaryUnit*arg(base))*expo)
def as_numer_denom(self):
if not self.is_commutative:
return self, S.One
base, exp = self.as_base_exp()
n, d = base.as_numer_denom()
# this should be the same as ExpBase.as_numer_denom wrt
# exponent handling
neg_exp = exp.is_negative
if exp.is_Mul and not neg_exp and not exp.is_positive:
neg_exp = exp.could_extract_minus_sign()
int_exp = exp.is_integer
# the denominator cannot be separated from the numerator if
# its sign is unknown unless the exponent is an integer, e.g.
# sqrt(a/b) != sqrt(a)/sqrt(b) when a=1 and b=-1. But if the
# denominator is negative the numerator and denominator can
# be negated and the denominator (now positive) separated.
if not (d.is_extended_real or int_exp):
n = base
d = S.One
dnonpos = d.is_nonpositive
if dnonpos:
n, d = -n, -d
elif dnonpos is None and not int_exp:
n = base
d = S.One
if neg_exp:
n, d = d, n
exp = -exp
if exp.is_infinite:
if n is S.One and d is not S.One:
return n, self.func(d, exp)
if n is not S.One and d is S.One:
return self.func(n, exp), d
return self.func(n, exp), self.func(d, exp)
def matches(self, expr, repl_dict=None, old=False):
expr = _sympify(expr)
if repl_dict is None:
repl_dict = {}
# special case, pattern = 1 and expr.exp can match to 0
if expr is S.One:
d = self.exp.matches(S.Zero, repl_dict)
if d is not None:
return d
# make sure the expression to be matched is an Expr
if not isinstance(expr, Expr):
return None
b, e = expr.as_base_exp()
# special case number
sb, se = self.as_base_exp()
if sb.is_Symbol and se.is_Integer and expr:
if e.is_rational:
return sb.matches(b**(e/se), repl_dict)
return sb.matches(expr**(1/se), repl_dict)
d = repl_dict.copy()
d = self.base.matches(b, d)
if d is None:
return None
d = self.exp.xreplace(d).matches(e, d)
if d is None:
return Expr.matches(self, expr, repl_dict)
return d
def _eval_nseries(self, x, n, logx, cdir=0):
# NOTE! This function is an important part of the gruntz algorithm
# for computing limits. It has to return a generalized power
# series with coefficients in C(log, log(x)). In more detail:
# It has to return an expression
# c_0*x**e_0 + c_1*x**e_1 + ... (finitely many terms)
# where e_i are numbers (not necessarily integers) and c_i are
# expressions involving only numbers, the log function, and log(x).
# The series expansion of b**e is computed as follows:
# 1) We express b as f*(1 + g) where f is the leading term of b.
# g has order O(x**d) where d is strictly positive.
# 2) Then b**e = (f**e)*((1 + g)**e).
# (1 + g)**e is computed using binomial series.
from sympy.functions.elementary.exponential import exp, log
from sympy.series.limits import limit
from sympy.series.order import Order
from sympy.core.sympify import sympify
if self.base is S.Exp1:
e_series = self.exp.nseries(x, n=n, logx=logx)
if e_series.is_Order:
return 1 + e_series
e0 = limit(e_series.removeO(), x, 0)
if e0 is S.NegativeInfinity:
return Order(x**n, x)
if e0 is S.Infinity:
return self
t = e_series - e0
exp_series = term = exp(e0)
# series of exp(e0 + t) in t
for i in range(1, n):
term *= t/i
term = term.nseries(x, n=n, logx=logx)
exp_series += term
exp_series += Order(t**n, x)
from sympy.simplify.powsimp import powsimp
return powsimp(exp_series, deep=True, combine='exp')
from sympy.simplify.powsimp import powdenest
from .numbers import _illegal
self = powdenest(self, force=True).trigsimp()
b, e = self.as_base_exp()
if e.has(*_illegal):
raise PoleError()
if e.has(x):
return exp(e*log(b))._eval_nseries(x, n=n, logx=logx, cdir=cdir)
if logx is not None and b.has(log):
from .symbol import Wild
c, ex = symbols('c, ex', cls=Wild, exclude=[x])
b = b.replace(log(c*x**ex), log(c) + ex*logx)
self = b**e
b = b.removeO()
try:
from sympy.functions.special.gamma_functions import polygamma
if b.has(polygamma, S.EulerGamma) and logx is not None:
raise ValueError()
_, m = b.leadterm(x)
except (ValueError, NotImplementedError, PoleError):
b = b._eval_nseries(x, n=max(2, n), logx=logx, cdir=cdir).removeO()
if b.has(S.NaN, S.ComplexInfinity):
raise NotImplementedError()
_, m = b.leadterm(x)
if e.has(log):
from sympy.simplify.simplify import logcombine
e = logcombine(e).cancel()
if not (m.is_zero or e.is_number and e.is_real):
if self == self._eval_as_leading_term(x, logx=logx, cdir=cdir):
res = exp(e*log(b))._eval_nseries(x, n=n, logx=logx, cdir=cdir)
if res == exp(e*log(b)):
return self
return res
f = b.as_leading_term(x, logx=logx)
g = (b/f - S.One).cancel(expand=False)
if not m.is_number:
raise NotImplementedError()
maxpow = n - m*e
if maxpow.has(Symbol):
maxpow = sympify(n)
if maxpow.is_negative:
return Order(x**(m*e), x)
if g.is_zero:
r = f**e
if r != self:
r += Order(x**n, x)
return r
def coeff_exp(term, x):
coeff, exp = S.One, S.Zero
for factor in Mul.make_args(term):
if factor.has(x):
base, exp = factor.as_base_exp()
if base != x:
try:
return term.leadterm(x)
except ValueError:
return term, S.Zero
else:
coeff *= factor
return coeff, exp
def mul(d1, d2):
res = {}
for e1, e2 in product(d1, d2):
ex = e1 + e2
if ex < maxpow:
res[ex] = res.get(ex, S.Zero) + d1[e1]*d2[e2]
return res
try:
c, d = g.leadterm(x, logx=logx)
except (ValueError, NotImplementedError):
if limit(g/x**maxpow, x, 0) == 0:
# g has higher order zero
return f**e + e*f**e*g # first term of binomial series
else:
raise NotImplementedError()
if c.is_Float and d == S.Zero:
# Convert floats like 0.5 to exact SymPy numbers like S.Half, to
# prevent rounding errors which can induce wrong values of d leading
# to a NotImplementedError being returned from the block below.
from sympy.simplify.simplify import nsimplify
_, d = nsimplify(g).leadterm(x, logx=logx)
if not d.is_positive:
g = g.simplify()
if g.is_zero:
return f**e
_, d = g.leadterm(x, logx=logx)
if not d.is_positive:
g = ((b - f)/f).expand()
_, d = g.leadterm(x, logx=logx)
if not d.is_positive:
raise NotImplementedError()
from sympy.functions.elementary.integers import ceiling
gpoly = g._eval_nseries(x, n=ceiling(maxpow), logx=logx, cdir=cdir).removeO()
gterms = {}
for term in Add.make_args(gpoly):
co1, e1 = coeff_exp(term, x)
gterms[e1] = gterms.get(e1, S.Zero) + co1
k = S.One
terms = {S.Zero: S.One}
tk = gterms
from sympy.functions.combinatorial.factorials import factorial, ff
while (k*d - maxpow).is_negative:
coeff = ff(e, k)/factorial(k)
for ex in tk:
terms[ex] = terms.get(ex, S.Zero) + coeff*tk[ex]
tk = mul(tk, gterms)
k += S.One
from sympy.functions.elementary.complexes import im
if not e.is_integer and m.is_zero and f.is_negative:
ndir = (b - f).dir(x, cdir)
if im(ndir).is_negative:
inco, inex = coeff_exp(f**e*(-1)**(-2*e), x)
elif im(ndir).is_zero:
inco, inex = coeff_exp(exp(e*log(b)).as_leading_term(x, logx=logx, cdir=cdir), x)
else:
inco, inex = coeff_exp(f**e, x)
else:
inco, inex = coeff_exp(f**e, x)
res = S.Zero
for e1 in terms:
ex = e1 + inex
res += terms[e1]*inco*x**(ex)
if not (e.is_integer and e.is_positive and (e*d - n).is_nonpositive and
res == _mexpand(self)):
try:
res += Order(x**n, x)
except NotImplementedError:
return exp(e*log(b))._eval_nseries(x, n=n, logx=logx, cdir=cdir)
return res
def _eval_as_leading_term(self, x, logx=None, cdir=0):
from sympy.functions.elementary.exponential import exp, log
e = self.exp
b = self.base
if self.base is S.Exp1:
arg = e.as_leading_term(x, logx=logx)
arg0 = arg.subs(x, 0)
if arg0 is S.NaN:
arg0 = arg.limit(x, 0)
if arg0.is_infinite is False:
return S.Exp1**arg0
raise PoleError("Cannot expand %s around 0" % (self))
elif e.has(x):
lt = exp(e * log(b))
return lt.as_leading_term(x, logx=logx, cdir=cdir)
else:
from sympy.functions.elementary.complexes import im
try:
f = b.as_leading_term(x, logx=logx, cdir=cdir)
except PoleError:
return self
if not e.is_integer and f.is_negative and not f.has(x):
ndir = (b - f).dir(x, cdir)
if im(ndir).is_negative:
# Normally, f**e would evaluate to exp(e*log(f)) but on branch cuts
# an other value is expected through the following computation
# exp(e*(log(f) - 2*pi*I)) == f**e*exp(-2*e*pi*I) == f**e*(-1)**(-2*e).
return self.func(f, e) * (-1)**(-2*e)
elif im(ndir).is_zero:
log_leadterm = log(b)._eval_as_leading_term(x, logx=logx, cdir=cdir)
if log_leadterm.is_infinite is False:
return exp(e*log_leadterm)
return self.func(f, e)
@cacheit
def _taylor_term(self, n, x, *previous_terms): # of (1 + x)**e
from sympy.functions.combinatorial.factorials import binomial
return binomial(self.exp, n) * self.func(x, n)
def taylor_term(self, n, x, *previous_terms):
if self.base is not S.Exp1:
return super().taylor_term(n, x, *previous_terms)
if n < 0:
return S.Zero
if n == 0:
return S.One
from .sympify import sympify
x = sympify(x)
if previous_terms:
p = previous_terms[-1]
if p is not None:
return p * x / n
from sympy.functions.combinatorial.factorials import factorial
return x**n/factorial(n)
def _eval_rewrite_as_sin(self, base, exp, **hints):
if self.base is S.Exp1:
from sympy.functions.elementary.trigonometric import sin
return sin(S.ImaginaryUnit*self.exp + S.Pi/2) - S.ImaginaryUnit*sin(S.ImaginaryUnit*self.exp)
def _eval_rewrite_as_cos(self, base, exp, **hints):
if self.base is S.Exp1:
from sympy.functions.elementary.trigonometric import cos
return cos(S.ImaginaryUnit*self.exp) + S.ImaginaryUnit*cos(S.ImaginaryUnit*self.exp + S.Pi/2)
def _eval_rewrite_as_tanh(self, base, exp, **hints):
if self.base is S.Exp1:
from sympy.functions.elementary.hyperbolic import tanh
return (1 + tanh(self.exp/2))/(1 - tanh(self.exp/2))
def _eval_rewrite_as_sqrt(self, base, exp, **kwargs):
from sympy.functions.elementary.trigonometric import sin, cos
if base is not S.Exp1:
return None
if exp.is_Mul:
coeff = exp.coeff(S.Pi * S.ImaginaryUnit)
if coeff and coeff.is_number:
cosine, sine = cos(S.Pi*coeff), sin(S.Pi*coeff)
if not isinstance(cosine, cos) and not isinstance (sine, sin):
return cosine + S.ImaginaryUnit*sine
def as_content_primitive(self, radical=False, clear=True):
"""Return the tuple (R, self/R) where R is the positive Rational
extracted from self.
Examples
========
>>> from sympy import sqrt
>>> sqrt(4 + 4*sqrt(2)).as_content_primitive()
(2, sqrt(1 + sqrt(2)))
>>> sqrt(3 + 3*sqrt(2)).as_content_primitive()
(1, sqrt(3)*sqrt(1 + sqrt(2)))
>>> from sympy import expand_power_base, powsimp, Mul
>>> from sympy.abc import x, y
>>> ((2*x + 2)**2).as_content_primitive()
(4, (x + 1)**2)
>>> (4**((1 + y)/2)).as_content_primitive()
(2, 4**(y/2))
>>> (3**((1 + y)/2)).as_content_primitive()
(1, 3**((y + 1)/2))
>>> (3**((5 + y)/2)).as_content_primitive()
(9, 3**((y + 1)/2))
>>> eq = 3**(2 + 2*x)
>>> powsimp(eq) == eq
True
>>> eq.as_content_primitive()
(9, 3**(2*x))
>>> powsimp(Mul(*_))
3**(2*x + 2)
>>> eq = (2 + 2*x)**y
>>> s = expand_power_base(eq); s.is_Mul, s
(False, (2*x + 2)**y)
>>> eq.as_content_primitive()
(1, (2*(x + 1))**y)
>>> s = expand_power_base(_[1]); s.is_Mul, s
(True, 2**y*(x + 1)**y)
See docstring of Expr.as_content_primitive for more examples.
"""
b, e = self.as_base_exp()
b = _keep_coeff(*b.as_content_primitive(radical=radical, clear=clear))
ce, pe = e.as_content_primitive(radical=radical, clear=clear)
if b.is_Rational:
#e
#= ce*pe
#= ce*(h + t)
#= ce*h + ce*t
#=> self
#= b**(ce*h)*b**(ce*t)
#= b**(cehp/cehq)*b**(ce*t)
#= b**(iceh + r/cehq)*b**(ce*t)
#= b**(iceh)*b**(r/cehq)*b**(ce*t)
#= b**(iceh)*b**(ce*t + r/cehq)
h, t = pe.as_coeff_Add()
if h.is_Rational and b != S.Zero:
ceh = ce*h
c = self.func(b, ceh)
r = S.Zero
if not c.is_Rational:
iceh, r = divmod(ceh.p, ceh.q)
c = self.func(b, iceh)
return c, self.func(b, _keep_coeff(ce, t + r/ce/ceh.q))
e = _keep_coeff(ce, pe)
# b**e = (h*t)**e = h**e*t**e = c*m*t**e
if e.is_Rational and b.is_Mul:
h, t = b.as_content_primitive(radical=radical, clear=clear) # h is positive
c, m = self.func(h, e).as_coeff_Mul() # so c is positive
m, me = m.as_base_exp()
if m is S.One or me == e: # probably always true
# return the following, not return c, m*Pow(t, e)
# which would change Pow into Mul; we let SymPy
# decide what to do by using the unevaluated Mul, e.g
# should it stay as sqrt(2 + 2*sqrt(5)) or become
# sqrt(2)*sqrt(1 + sqrt(5))
return c, self.func(_keep_coeff(m, t), e)
return S.One, self.func(b, e)
def is_constant(self, *wrt, **flags):
expr = self
if flags.get('simplify', True):
expr = expr.simplify()
b, e = expr.as_base_exp()
bz = b.equals(0)
if bz: # recalculate with assumptions in case it's unevaluated
new = b**e
if new != expr:
return new.is_constant()
econ = e.is_constant(*wrt)
bcon = b.is_constant(*wrt)
if bcon:
if econ:
return True
bz = b.equals(0)
if bz is False:
return False
elif bcon is None:
return None
return e.equals(0)
def _eval_difference_delta(self, n, step):
b, e = self.args
if e.has(n) and not b.has(n):
new_e = e.subs(n, n + step)
return (b**(new_e - e) - 1) * self
power = Dispatcher('power')
power.add((object, object), Pow)
from .add import Add
from .numbers import Integer, Rational
from .mul import Mul, _keep_coeff
from .symbol import Symbol, Dummy, symbols
PK ]ZZZe�К� � sympy/core/random.py"""
When you need to use random numbers in SymPy library code, import from here
so there is only one generator working for SymPy. Imports from here should
behave the same as if they were being imported from Python's random module.
But only the routines currently used in SymPy are included here. To use others
import ``rng`` and access the method directly. For example, to capture the
current state of the generator use ``rng.getstate()``.
There is intentionally no Random to import from here. If you want
to control the state of the generator, import ``seed`` and call it
with or without an argument to set the state.
Examples
========
>>> from sympy.core.random import random, seed
>>> assert random() < 1
>>> seed(1); a = random()
>>> b = random()
>>> seed(1); c = random()
>>> assert a == c
>>> assert a != b # remote possibility this will fail
"""
from sympy.utilities.iterables import is_sequence
from sympy.utilities.misc import as_int
import random as _random
rng = _random.Random()
choice = rng.choice
random = rng.random
randint = rng.randint
randrange = rng.randrange
sample = rng.sample
# seed = rng.seed
shuffle = rng.shuffle
uniform = rng.uniform
_assumptions_rng = _random.Random()
_assumptions_shuffle = _assumptions_rng.shuffle
def seed(a=None, version=2):
rng.seed(a=a, version=version)
_assumptions_rng.seed(a=a, version=version)
def random_complex_number(a=2, b=-1, c=3, d=1, rational=False, tolerance=None):
"""
Return a random complex number.
To reduce chance of hitting branch cuts or anything, we guarantee
b <= Im z <= d, a <= Re z <= c
When rational is True, a rational approximation to a random number
is obtained within specified tolerance, if any.
"""
from sympy.core.numbers import I
from sympy.simplify.simplify import nsimplify
A, B = uniform(a, c), uniform(b, d)
if not rational:
return A + I*B
return (nsimplify(A, rational=True, tolerance=tolerance) +
I*nsimplify(B, rational=True, tolerance=tolerance))
def verify_numerically(f, g, z=None, tol=1.0e-6, a=2, b=-1, c=3, d=1):
"""
Test numerically that f and g agree when evaluated in the argument z.
If z is None, all symbols will be tested. This routine does not test
whether there are Floats present with precision higher than 15 digits
so if there are, your results may not be what you expect due to round-
off errors.
Examples
========
>>> from sympy import sin, cos
>>> from sympy.abc import x
>>> from sympy.core.random import verify_numerically as tn
>>> tn(sin(x)**2 + cos(x)**2, 1, x)
True
"""
from sympy.core.symbol import Symbol
from sympy.core.sympify import sympify
from sympy.core.numbers import comp
f, g = (sympify(i) for i in (f, g))
if z is None:
z = f.free_symbols | g.free_symbols
elif isinstance(z, Symbol):
z = [z]
reps = list(zip(z, [random_complex_number(a, b, c, d) for _ in z]))
z1 = f.subs(reps).n()
z2 = g.subs(reps).n()
return comp(z1, z2, tol)
def test_derivative_numerically(f, z, tol=1.0e-6, a=2, b=-1, c=3, d=1):
"""
Test numerically that the symbolically computed derivative of f
with respect to z is correct.
This routine does not test whether there are Floats present with
precision higher than 15 digits so if there are, your results may
not be what you expect due to round-off errors.
Examples
========
>>> from sympy import sin
>>> from sympy.abc import x
>>> from sympy.core.random import test_derivative_numerically as td
>>> td(sin(x), x)
True
"""
from sympy.core.numbers import comp
from sympy.core.function import Derivative
z0 = random_complex_number(a, b, c, d)
f1 = f.diff(z).subs(z, z0)
f2 = Derivative(f, z).doit_numerically(z0)
return comp(f1.n(), f2.n(), tol)
def _randrange(seed=None):
"""Return a randrange generator.
``seed`` can be
* None - return randomly seeded generator
* int - return a generator seeded with the int
* list - the values to be returned will be taken from the list
in the order given; the provided list is not modified.
Examples
========
>>> from sympy.core.random import _randrange
>>> rr = _randrange()
>>> rr(1000) # doctest: +SKIP
999
>>> rr = _randrange(3)
>>> rr(1000) # doctest: +SKIP
238
>>> rr = _randrange([0, 5, 1, 3, 4])
>>> rr(3), rr(3)
(0, 1)
"""
if seed is None:
return randrange
elif isinstance(seed, int):
rng.seed(seed)
return randrange
elif is_sequence(seed):
seed = list(seed) # make a copy
seed.reverse()
def give(a, b=None, seq=seed):
if b is None:
a, b = 0, a
a, b = as_int(a), as_int(b)
w = b - a
if w < 1:
raise ValueError('_randrange got empty range')
try:
x = seq.pop()
except IndexError:
raise ValueError('_randrange sequence was too short')
if a <= x < b:
return x
else:
return give(a, b, seq)
return give
else:
raise ValueError('_randrange got an unexpected seed')
def _randint(seed=None):
"""Return a randint generator.
``seed`` can be
* None - return randomly seeded generator
* int - return a generator seeded with the int
* list - the values to be returned will be taken from the list
in the order given; the provided list is not modified.
Examples
========
>>> from sympy.core.random import _randint
>>> ri = _randint()
>>> ri(1, 1000) # doctest: +SKIP
999
>>> ri = _randint(3)
>>> ri(1, 1000) # doctest: +SKIP
238
>>> ri = _randint([0, 5, 1, 2, 4])
>>> ri(1, 3), ri(1, 3)
(1, 2)
"""
if seed is None:
return randint
elif isinstance(seed, int):
rng.seed(seed)
return randint
elif is_sequence(seed):
seed = list(seed) # make a copy
seed.reverse()
def give(a, b, seq=seed):
a, b = as_int(a), as_int(b)
w = b - a
if w < 0:
raise ValueError('_randint got empty range')
try:
x = seq.pop()
except IndexError:
raise ValueError('_randint sequence was too short')
if a <= x <= b:
return x
else:
return give(a, b, seq)
return give
else:
raise ValueError('_randint got an unexpected seed')
PK ]ZZZ(�T��� �� sympy/core/relational.pyfrom __future__ import annotations
from .basic import Atom, Basic
from .sorting import ordered
from .evalf import EvalfMixin
from .function import AppliedUndef
from .numbers import int_valued
from .singleton import S
from .sympify import _sympify, SympifyError
from .parameters import global_parameters
from .logic import fuzzy_bool, fuzzy_xor, fuzzy_and, fuzzy_not
from sympy.logic.boolalg import Boolean, BooleanAtom
from sympy.utilities.iterables import sift
from sympy.utilities.misc import filldedent
from sympy.utilities.exceptions import sympy_deprecation_warning
__all__ = (
'Rel', 'Eq', 'Ne', 'Lt', 'Le', 'Gt', 'Ge',
'Relational', 'Equality', 'Unequality', 'StrictLessThan', 'LessThan',
'StrictGreaterThan', 'GreaterThan',
)
from .expr import Expr
from sympy.multipledispatch import dispatch
from .containers import Tuple
from .symbol import Symbol
def _nontrivBool(side):
return isinstance(side, Boolean) and \
not isinstance(side, Atom)
# Note, see issue 4986. Ideally, we wouldn't want to subclass both Boolean
# and Expr.
# from .. import Expr
def _canonical(cond):
# return a condition in which all relationals are canonical
reps = {r: r.canonical for r in cond.atoms(Relational)}
return cond.xreplace(reps)
# XXX: AttributeError was being caught here but it wasn't triggered by any of
# the tests so I've removed it...
def _canonical_coeff(rel):
# return -2*x + 1 < 0 as x > 1/2
# XXX make this part of Relational.canonical?
rel = rel.canonical
if not rel.is_Relational or rel.rhs.is_Boolean:
return rel # Eq(x, True)
b, l = rel.lhs.as_coeff_Add(rational=True)
m, lhs = l.as_coeff_Mul(rational=True)
rhs = (rel.rhs - b)/m
if m < 0:
return rel.reversed.func(lhs, rhs)
return rel.func(lhs, rhs)
class Relational(Boolean, EvalfMixin):
"""Base class for all relation types.
Explanation
===========
Subclasses of Relational should generally be instantiated directly, but
Relational can be instantiated with a valid ``rop`` value to dispatch to
the appropriate subclass.
Parameters
==========
rop : str or None
Indicates what subclass to instantiate. Valid values can be found
in the keys of Relational.ValidRelationOperator.
Examples
========
>>> from sympy import Rel
>>> from sympy.abc import x, y
>>> Rel(y, x + x**2, '==')
Eq(y, x**2 + x)
A relation's type can be defined upon creation using ``rop``.
The relation type of an existing expression can be obtained
using its ``rel_op`` property.
Here is a table of all the relation types, along with their
``rop`` and ``rel_op`` values:
+---------------------+----------------------------+------------+
|Relation |``rop`` |``rel_op`` |
+=====================+============================+============+
|``Equality`` |``==`` or ``eq`` or ``None``|``==`` |
+---------------------+----------------------------+------------+
|``Unequality`` |``!=`` or ``ne`` |``!=`` |
+---------------------+----------------------------+------------+
|``GreaterThan`` |``>=`` or ``ge`` |``>=`` |
+---------------------+----------------------------+------------+
|``LessThan`` |``<=`` or ``le`` |``<=`` |
+---------------------+----------------------------+------------+
|``StrictGreaterThan``|``>`` or ``gt`` |``>`` |
+---------------------+----------------------------+------------+
|``StrictLessThan`` |``<`` or ``lt`` |``<`` |
+---------------------+----------------------------+------------+
For example, setting ``rop`` to ``==`` produces an
``Equality`` relation, ``Eq()``.
So does setting ``rop`` to ``eq``, or leaving ``rop`` unspecified.
That is, the first three ``Rel()`` below all produce the same result.
Using a ``rop`` from a different row in the table produces a
different relation type.
For example, the fourth ``Rel()`` below using ``lt`` for ``rop``
produces a ``StrictLessThan`` inequality:
>>> from sympy import Rel
>>> from sympy.abc import x, y
>>> Rel(y, x + x**2, '==')
Eq(y, x**2 + x)
>>> Rel(y, x + x**2, 'eq')
Eq(y, x**2 + x)
>>> Rel(y, x + x**2)
Eq(y, x**2 + x)
>>> Rel(y, x + x**2, 'lt')
y < x**2 + x
To obtain the relation type of an existing expression,
get its ``rel_op`` property.
For example, ``rel_op`` is ``==`` for the ``Equality`` relation above,
and ``<`` for the strict less than inequality above:
>>> from sympy import Rel
>>> from sympy.abc import x, y
>>> my_equality = Rel(y, x + x**2, '==')
>>> my_equality.rel_op
'=='
>>> my_inequality = Rel(y, x + x**2, 'lt')
>>> my_inequality.rel_op
'<'
"""
__slots__ = ()
ValidRelationOperator: dict[str | None, type[Relational]] = {}
is_Relational = True
# ValidRelationOperator - Defined below, because the necessary classes
# have not yet been defined
def __new__(cls, lhs, rhs, rop=None, **assumptions):
# If called by a subclass, do nothing special and pass on to Basic.
if cls is not Relational:
return Basic.__new__(cls, lhs, rhs, **assumptions)
# XXX: Why do this? There should be a separate function to make a
# particular subclass of Relational from a string.
#
# If called directly with an operator, look up the subclass
# corresponding to that operator and delegate to it
cls = cls.ValidRelationOperator.get(rop, None)
if cls is None:
raise ValueError("Invalid relational operator symbol: %r" % rop)
if not issubclass(cls, (Eq, Ne)):
# validate that Booleans are not being used in a relational
# other than Eq/Ne;
# Note: Symbol is a subclass of Boolean but is considered
# acceptable here.
if any(map(_nontrivBool, (lhs, rhs))):
raise TypeError(filldedent('''
A Boolean argument can only be used in
Eq and Ne; all other relationals expect
real expressions.
'''))
return cls(lhs, rhs, **assumptions)
@property
def lhs(self):
"""The left-hand side of the relation."""
return self._args[0]
@property
def rhs(self):
"""The right-hand side of the relation."""
return self._args[1]
@property
def reversed(self):
"""Return the relationship with sides reversed.
Examples
========
>>> from sympy import Eq
>>> from sympy.abc import x
>>> Eq(x, 1)
Eq(x, 1)
>>> _.reversed
Eq(1, x)
>>> x < 1
x < 1
>>> _.reversed
1 > x
"""
ops = {Eq: Eq, Gt: Lt, Ge: Le, Lt: Gt, Le: Ge, Ne: Ne}
a, b = self.args
return Relational.__new__(ops.get(self.func, self.func), b, a)
@property
def reversedsign(self):
"""Return the relationship with signs reversed.
Examples
========
>>> from sympy import Eq
>>> from sympy.abc import x
>>> Eq(x, 1)
Eq(x, 1)
>>> _.reversedsign
Eq(-x, -1)
>>> x < 1
x < 1
>>> _.reversedsign
-x > -1
"""
a, b = self.args
if not (isinstance(a, BooleanAtom) or isinstance(b, BooleanAtom)):
ops = {Eq: Eq, Gt: Lt, Ge: Le, Lt: Gt, Le: Ge, Ne: Ne}
return Relational.__new__(ops.get(self.func, self.func), -a, -b)
else:
return self
@property
def negated(self):
"""Return the negated relationship.
Examples
========
>>> from sympy import Eq
>>> from sympy.abc import x
>>> Eq(x, 1)
Eq(x, 1)
>>> _.negated
Ne(x, 1)
>>> x < 1
x < 1
>>> _.negated
x >= 1
Notes
=====
This works more or less identical to ``~``/``Not``. The difference is
that ``negated`` returns the relationship even if ``evaluate=False``.
Hence, this is useful in code when checking for e.g. negated relations
to existing ones as it will not be affected by the `evaluate` flag.
"""
ops = {Eq: Ne, Ge: Lt, Gt: Le, Le: Gt, Lt: Ge, Ne: Eq}
# If there ever will be new Relational subclasses, the following line
# will work until it is properly sorted out
# return ops.get(self.func, lambda a, b, evaluate=False: ~(self.func(a,
# b, evaluate=evaluate)))(*self.args, evaluate=False)
return Relational.__new__(ops.get(self.func), *self.args)
@property
def weak(self):
"""return the non-strict version of the inequality or self
EXAMPLES
========
>>> from sympy.abc import x
>>> (x < 1).weak
x <= 1
>>> _.weak
x <= 1
"""
return self
@property
def strict(self):
"""return the strict version of the inequality or self
EXAMPLES
========
>>> from sympy.abc import x
>>> (x <= 1).strict
x < 1
>>> _.strict
x < 1
"""
return self
def _eval_evalf(self, prec):
return self.func(*[s._evalf(prec) for s in self.args])
@property
def canonical(self):
"""Return a canonical form of the relational by putting a
number on the rhs, canonically removing a sign or else
ordering the args canonically. No other simplification is
attempted.
Examples
========
>>> from sympy.abc import x, y
>>> x < 2
x < 2
>>> _.reversed.canonical
x < 2
>>> (-y < x).canonical
x > -y
>>> (-y > x).canonical
x < -y
>>> (-y < -x).canonical
x < y
The canonicalization is recursively applied:
>>> from sympy import Eq
>>> Eq(x < y, y > x).canonical
True
"""
args = tuple([i.canonical if isinstance(i, Relational) else i for i in self.args])
if args != self.args:
r = self.func(*args)
if not isinstance(r, Relational):
return r
else:
r = self
if r.rhs.is_number:
if r.rhs.is_Number and r.lhs.is_Number and r.lhs > r.rhs:
r = r.reversed
elif r.lhs.is_number:
r = r.reversed
elif tuple(ordered(args)) != args:
r = r.reversed
LHS_CEMS = getattr(r.lhs, 'could_extract_minus_sign', None)
RHS_CEMS = getattr(r.rhs, 'could_extract_minus_sign', None)
if isinstance(r.lhs, BooleanAtom) or isinstance(r.rhs, BooleanAtom):
return r
# Check if first value has negative sign
if LHS_CEMS and LHS_CEMS():
return r.reversedsign
elif not r.rhs.is_number and RHS_CEMS and RHS_CEMS():
# Right hand side has a minus, but not lhs.
# How does the expression with reversed signs behave?
# This is so that expressions of the type
# Eq(x, -y) and Eq(-x, y)
# have the same canonical representation
expr1, _ = ordered([r.lhs, -r.rhs])
if expr1 != r.lhs:
return r.reversed.reversedsign
return r
def equals(self, other, failing_expression=False):
"""Return True if the sides of the relationship are mathematically
identical and the type of relationship is the same.
If failing_expression is True, return the expression whose truth value
was unknown."""
if isinstance(other, Relational):
if other in (self, self.reversed):
return True
a, b = self, other
if a.func in (Eq, Ne) or b.func in (Eq, Ne):
if a.func != b.func:
return False
left, right = [i.equals(j,
failing_expression=failing_expression)
for i, j in zip(a.args, b.args)]
if left is True:
return right
if right is True:
return left
lr, rl = [i.equals(j, failing_expression=failing_expression)
for i, j in zip(a.args, b.reversed.args)]
if lr is True:
return rl
if rl is True:
return lr
e = (left, right, lr, rl)
if all(i is False for i in e):
return False
for i in e:
if i not in (True, False):
return i
else:
if b.func != a.func:
b = b.reversed
if a.func != b.func:
return False
left = a.lhs.equals(b.lhs,
failing_expression=failing_expression)
if left is False:
return False
right = a.rhs.equals(b.rhs,
failing_expression=failing_expression)
if right is False:
return False
if left is True:
return right
return left
def _eval_simplify(self, **kwargs):
from .add import Add
from .expr import Expr
r = self
r = r.func(*[i.simplify(**kwargs) for i in r.args])
if r.is_Relational:
if not isinstance(r.lhs, Expr) or not isinstance(r.rhs, Expr):
return r
dif = r.lhs - r.rhs
# replace dif with a valid Number that will
# allow a definitive comparison with 0
v = None
if dif.is_comparable:
v = dif.n(2)
if any(i._prec == 1 for i in v.as_real_imag()):
rv, iv = [i.n(2) for i in dif.as_real_imag()]
v = rv + S.ImaginaryUnit*iv
elif dif.equals(0): # XXX this is expensive
v = S.Zero
if v is not None:
r = r.func._eval_relation(v, S.Zero)
r = r.canonical
# If there is only one symbol in the expression,
# try to write it on a simplified form
free = list(filter(lambda x: x.is_real is not False, r.free_symbols))
if len(free) == 1:
try:
from sympy.solvers.solveset import linear_coeffs
x = free.pop()
dif = r.lhs - r.rhs
m, b = linear_coeffs(dif, x)
if m.is_zero is False:
if m.is_negative:
# Dividing with a negative number, so change order of arguments
# canonical will put the symbol back on the lhs later
r = r.func(-b / m, x)
else:
r = r.func(x, -b / m)
else:
r = r.func(b, S.Zero)
except ValueError:
# maybe not a linear function, try polynomial
from sympy.polys.polyerrors import PolynomialError
from sympy.polys.polytools import gcd, Poly, poly
try:
p = poly(dif, x)
c = p.all_coeffs()
constant = c[-1]
c[-1] = 0
scale = gcd(c)
c = [ctmp / scale for ctmp in c]
r = r.func(Poly.from_list(c, x).as_expr(), -constant / scale)
except PolynomialError:
pass
elif len(free) >= 2:
try:
from sympy.solvers.solveset import linear_coeffs
from sympy.polys.polytools import gcd
free = list(ordered(free))
dif = r.lhs - r.rhs
m = linear_coeffs(dif, *free)
constant = m[-1]
del m[-1]
scale = gcd(m)
m = [mtmp / scale for mtmp in m]
nzm = list(filter(lambda f: f[0] != 0, list(zip(m, free))))
if scale.is_zero is False:
if constant != 0:
# lhs: expression, rhs: constant
newexpr = Add(*[i * j for i, j in nzm])
r = r.func(newexpr, -constant / scale)
else:
# keep first term on lhs
lhsterm = nzm[0][0] * nzm[0][1]
del nzm[0]
newexpr = Add(*[i * j for i, j in nzm])
r = r.func(lhsterm, -newexpr)
else:
r = r.func(constant, S.Zero)
except ValueError:
pass
# Did we get a simplified result?
r = r.canonical
measure = kwargs['measure']
if measure(r) < kwargs['ratio'] * measure(self):
return r
else:
return self
def _eval_trigsimp(self, **opts):
from sympy.simplify.trigsimp import trigsimp
return self.func(trigsimp(self.lhs, **opts), trigsimp(self.rhs, **opts))
def expand(self, **kwargs):
args = (arg.expand(**kwargs) for arg in self.args)
return self.func(*args)
def __bool__(self):
raise TypeError("cannot determine truth value of Relational")
def _eval_as_set(self):
# self is univariate and periodicity(self, x) in (0, None)
from sympy.solvers.inequalities import solve_univariate_inequality
from sympy.sets.conditionset import ConditionSet
syms = self.free_symbols
assert len(syms) == 1
x = syms.pop()
try:
xset = solve_univariate_inequality(self, x, relational=False)
except NotImplementedError:
# solve_univariate_inequality raises NotImplementedError for
# unsolvable equations/inequalities.
xset = ConditionSet(x, self, S.Reals)
return xset
@property
def binary_symbols(self):
# override where necessary
return set()
Rel = Relational
class Equality(Relational):
"""
An equal relation between two objects.
Explanation
===========
Represents that two objects are equal. If they can be easily shown
to be definitively equal (or unequal), this will reduce to True (or
False). Otherwise, the relation is maintained as an unevaluated
Equality object. Use the ``simplify`` function on this object for
more nontrivial evaluation of the equality relation.
As usual, the keyword argument ``evaluate=False`` can be used to
prevent any evaluation.
Examples
========
>>> from sympy import Eq, simplify, exp, cos
>>> from sympy.abc import x, y
>>> Eq(y, x + x**2)
Eq(y, x**2 + x)
>>> Eq(2, 5)
False
>>> Eq(2, 5, evaluate=False)
Eq(2, 5)
>>> _.doit()
False
>>> Eq(exp(x), exp(x).rewrite(cos))
Eq(exp(x), sinh(x) + cosh(x))
>>> simplify(_)
True
See Also
========
sympy.logic.boolalg.Equivalent : for representing equality between two
boolean expressions
Notes
=====
Python treats 1 and True (and 0 and False) as being equal; SymPy
does not. And integer will always compare as unequal to a Boolean:
>>> Eq(True, 1), True == 1
(False, True)
This class is not the same as the == operator. The == operator tests
for exact structural equality between two expressions; this class
compares expressions mathematically.
If either object defines an ``_eval_Eq`` method, it can be used in place of
the default algorithm. If ``lhs._eval_Eq(rhs)`` or ``rhs._eval_Eq(lhs)``
returns anything other than None, that return value will be substituted for
the Equality. If None is returned by ``_eval_Eq``, an Equality object will
be created as usual.
Since this object is already an expression, it does not respond to
the method ``as_expr`` if one tries to create `x - y` from ``Eq(x, y)``.
If ``eq = Eq(x, y)`` then write `eq.lhs - eq.rhs` to get ``x - y``.
.. deprecated:: 1.5
``Eq(expr)`` with a single argument is a shorthand for ``Eq(expr, 0)``,
but this behavior is deprecated and will be removed in a future version
of SymPy.
"""
rel_op = '=='
__slots__ = ()
is_Equality = True
def __new__(cls, lhs, rhs, **options):
evaluate = options.pop('evaluate', global_parameters.evaluate)
lhs = _sympify(lhs)
rhs = _sympify(rhs)
if evaluate:
val = is_eq(lhs, rhs)
if val is None:
return cls(lhs, rhs, evaluate=False)
else:
return _sympify(val)
return Relational.__new__(cls, lhs, rhs)
@classmethod
def _eval_relation(cls, lhs, rhs):
return _sympify(lhs == rhs)
def _eval_rewrite_as_Add(self, L, R, evaluate=True, **kwargs):
"""
return Eq(L, R) as L - R. To control the evaluation of
the result set pass `evaluate=True` to give L - R;
if `evaluate=None` then terms in L and R will not cancel
but they will be listed in canonical order; otherwise
non-canonical args will be returned. If one side is 0, the
non-zero side will be returned.
.. deprecated:: 1.13
The method ``Eq.rewrite(Add)`` is deprecated.
See :ref:`eq-rewrite-Add` for details.
Examples
========
>>> from sympy import Eq, Add
>>> from sympy.abc import b, x
>>> eq = Eq(x + b, x - b)
>>> eq.rewrite(Add) #doctest: +SKIP
2*b
>>> eq.rewrite(Add, evaluate=None).args #doctest: +SKIP
(b, b, x, -x)
>>> eq.rewrite(Add, evaluate=False).args #doctest: +SKIP
(b, x, b, -x)
"""
sympy_deprecation_warning("""
Eq.rewrite(Add) is deprecated.
For ``eq = Eq(a, b)`` use ``eq.lhs - eq.rhs`` to obtain
``a - b``.
""",
deprecated_since_version="1.13",
active_deprecations_target="eq-rewrite-Add",
stacklevel=5,
)
from .add import _unevaluated_Add, Add
if L == 0:
return R
if R == 0:
return L
if evaluate:
# allow cancellation of args
return L - R
args = Add.make_args(L) + Add.make_args(-R)
if evaluate is None:
# no cancellation, but canonical
return _unevaluated_Add(*args)
# no cancellation, not canonical
return Add._from_args(args)
@property
def binary_symbols(self):
if S.true in self.args or S.false in self.args:
if self.lhs.is_Symbol:
return {self.lhs}
elif self.rhs.is_Symbol:
return {self.rhs}
return set()
def _eval_simplify(self, **kwargs):
# standard simplify
e = super()._eval_simplify(**kwargs)
if not isinstance(e, Equality):
return e
from .expr import Expr
if not isinstance(e.lhs, Expr) or not isinstance(e.rhs, Expr):
return e
free = self.free_symbols
if len(free) == 1:
try:
from .add import Add
from sympy.solvers.solveset import linear_coeffs
x = free.pop()
m, b = linear_coeffs(
Add(e.lhs, -e.rhs, evaluate=False), x)
if m.is_zero is False:
enew = e.func(x, -b / m)
else:
enew = e.func(m * x, -b)
measure = kwargs['measure']
if measure(enew) <= kwargs['ratio'] * measure(e):
e = enew
except ValueError:
pass
return e.canonical
def integrate(self, *args, **kwargs):
"""See the integrate function in sympy.integrals"""
from sympy.integrals.integrals import integrate
return integrate(self, *args, **kwargs)
def as_poly(self, *gens, **kwargs):
'''Returns lhs-rhs as a Poly
Examples
========
>>> from sympy import Eq
>>> from sympy.abc import x
>>> Eq(x**2, 1).as_poly(x)
Poly(x**2 - 1, x, domain='ZZ')
'''
return (self.lhs - self.rhs).as_poly(*gens, **kwargs)
Eq = Equality
class Unequality(Relational):
"""An unequal relation between two objects.
Explanation
===========
Represents that two objects are not equal. If they can be shown to be
definitively equal, this will reduce to False; if definitively unequal,
this will reduce to True. Otherwise, the relation is maintained as an
Unequality object.
Examples
========
>>> from sympy import Ne
>>> from sympy.abc import x, y
>>> Ne(y, x+x**2)
Ne(y, x**2 + x)
See Also
========
Equality
Notes
=====
This class is not the same as the != operator. The != operator tests
for exact structural equality between two expressions; this class
compares expressions mathematically.
This class is effectively the inverse of Equality. As such, it uses the
same algorithms, including any available `_eval_Eq` methods.
"""
rel_op = '!='
__slots__ = ()
def __new__(cls, lhs, rhs, **options):
lhs = _sympify(lhs)
rhs = _sympify(rhs)
evaluate = options.pop('evaluate', global_parameters.evaluate)
if evaluate:
val = is_neq(lhs, rhs)
if val is None:
return cls(lhs, rhs, evaluate=False)
else:
return _sympify(val)
return Relational.__new__(cls, lhs, rhs, **options)
@classmethod
def _eval_relation(cls, lhs, rhs):
return _sympify(lhs != rhs)
@property
def binary_symbols(self):
if S.true in self.args or S.false in self.args:
if self.lhs.is_Symbol:
return {self.lhs}
elif self.rhs.is_Symbol:
return {self.rhs}
return set()
def _eval_simplify(self, **kwargs):
# simplify as an equality
eq = Equality(*self.args)._eval_simplify(**kwargs)
if isinstance(eq, Equality):
# send back Ne with the new args
return self.func(*eq.args)
return eq.negated # result of Ne is the negated Eq
Ne = Unequality
class _Inequality(Relational):
"""Internal base class for all *Than types.
Each subclass must implement _eval_relation to provide the method for
comparing two real numbers.
"""
__slots__ = ()
def __new__(cls, lhs, rhs, **options):
try:
lhs = _sympify(lhs)
rhs = _sympify(rhs)
except SympifyError:
return NotImplemented
evaluate = options.pop('evaluate', global_parameters.evaluate)
if evaluate:
for me in (lhs, rhs):
if me.is_extended_real is False:
raise TypeError("Invalid comparison of non-real %s" % me)
if me is S.NaN:
raise TypeError("Invalid NaN comparison")
# First we invoke the appropriate inequality method of `lhs`
# (e.g., `lhs.__lt__`). That method will try to reduce to
# boolean or raise an exception. It may keep calling
# superclasses until it reaches `Expr` (e.g., `Expr.__lt__`).
# In some cases, `Expr` will just invoke us again (if neither it
# nor a subclass was able to reduce to boolean or raise an
# exception). In that case, it must call us with
# `evaluate=False` to prevent infinite recursion.
return cls._eval_relation(lhs, rhs, **options)
# make a "non-evaluated" Expr for the inequality
return Relational.__new__(cls, lhs, rhs, **options)
@classmethod
def _eval_relation(cls, lhs, rhs, **options):
val = cls._eval_fuzzy_relation(lhs, rhs)
if val is None:
return cls(lhs, rhs, evaluate=False)
else:
return _sympify(val)
class _Greater(_Inequality):
"""Not intended for general use
_Greater is only used so that GreaterThan and StrictGreaterThan may
subclass it for the .gts and .lts properties.
"""
__slots__ = ()
@property
def gts(self):
return self._args[0]
@property
def lts(self):
return self._args[1]
class _Less(_Inequality):
"""Not intended for general use.
_Less is only used so that LessThan and StrictLessThan may subclass it for
the .gts and .lts properties.
"""
__slots__ = ()
@property
def gts(self):
return self._args[1]
@property
def lts(self):
return self._args[0]
class GreaterThan(_Greater):
r"""Class representations of inequalities.
Explanation
===========
The ``*Than`` classes represent inequal relationships, where the left-hand
side is generally bigger or smaller than the right-hand side. For example,
the GreaterThan class represents an inequal relationship where the
left-hand side is at least as big as the right side, if not bigger. In
mathematical notation:
lhs $\ge$ rhs
In total, there are four ``*Than`` classes, to represent the four
inequalities:
+-----------------+--------+
|Class Name | Symbol |
+=================+========+
|GreaterThan | ``>=`` |
+-----------------+--------+
|LessThan | ``<=`` |
+-----------------+--------+
|StrictGreaterThan| ``>`` |
+-----------------+--------+
|StrictLessThan | ``<`` |
+-----------------+--------+
All classes take two arguments, lhs and rhs.
+----------------------------+-----------------+
|Signature Example | Math Equivalent |
+============================+=================+
|GreaterThan(lhs, rhs) | lhs $\ge$ rhs |
+----------------------------+-----------------+
|LessThan(lhs, rhs) | lhs $\le$ rhs |
+----------------------------+-----------------+
|StrictGreaterThan(lhs, rhs) | lhs $>$ rhs |
+----------------------------+-----------------+
|StrictLessThan(lhs, rhs) | lhs $<$ rhs |
+----------------------------+-----------------+
In addition to the normal .lhs and .rhs of Relations, ``*Than`` inequality
objects also have the .lts and .gts properties, which represent the "less
than side" and "greater than side" of the operator. Use of .lts and .gts
in an algorithm rather than .lhs and .rhs as an assumption of inequality
direction will make more explicit the intent of a certain section of code,
and will make it similarly more robust to client code changes:
>>> from sympy import GreaterThan, StrictGreaterThan
>>> from sympy import LessThan, StrictLessThan
>>> from sympy import And, Ge, Gt, Le, Lt, Rel, S
>>> from sympy.abc import x, y, z
>>> from sympy.core.relational import Relational
>>> e = GreaterThan(x, 1)
>>> e
x >= 1
>>> '%s >= %s is the same as %s <= %s' % (e.gts, e.lts, e.lts, e.gts)
'x >= 1 is the same as 1 <= x'
Examples
========
One generally does not instantiate these classes directly, but uses various
convenience methods:
>>> for f in [Ge, Gt, Le, Lt]: # convenience wrappers
... print(f(x, 2))
x >= 2
x > 2
x <= 2
x < 2
Another option is to use the Python inequality operators (``>=``, ``>``,
``<=``, ``<``) directly. Their main advantage over the ``Ge``, ``Gt``,
``Le``, and ``Lt`` counterparts, is that one can write a more
"mathematical looking" statement rather than littering the math with
oddball function calls. However there are certain (minor) caveats of
which to be aware (search for 'gotcha', below).
>>> x >= 2
x >= 2
>>> _ == Ge(x, 2)
True
However, it is also perfectly valid to instantiate a ``*Than`` class less
succinctly and less conveniently:
>>> Rel(x, 1, ">")
x > 1
>>> Relational(x, 1, ">")
x > 1
>>> StrictGreaterThan(x, 1)
x > 1
>>> GreaterThan(x, 1)
x >= 1
>>> LessThan(x, 1)
x <= 1
>>> StrictLessThan(x, 1)
x < 1
Notes
=====
There are a couple of "gotchas" to be aware of when using Python's
operators.
The first is that what your write is not always what you get:
>>> 1 < x
x > 1
Due to the order that Python parses a statement, it may
not immediately find two objects comparable. When ``1 < x``
is evaluated, Python recognizes that the number 1 is a native
number and that x is *not*. Because a native Python number does
not know how to compare itself with a SymPy object
Python will try the reflective operation, ``x > 1`` and that is the
form that gets evaluated, hence returned.
If the order of the statement is important (for visual output to
the console, perhaps), one can work around this annoyance in a
couple ways:
(1) "sympify" the literal before comparison
>>> S(1) < x
1 < x
(2) use one of the wrappers or less succinct methods described
above
>>> Lt(1, x)
1 < x
>>> Relational(1, x, "<")
1 < x
The second gotcha involves writing equality tests between relationals
when one or both sides of the test involve a literal relational:
>>> e = x < 1; e
x < 1
>>> e == e # neither side is a literal
True
>>> e == x < 1 # expecting True, too
False
>>> e != x < 1 # expecting False
x < 1
>>> x < 1 != x < 1 # expecting False or the same thing as before
Traceback (most recent call last):
...
TypeError: cannot determine truth value of Relational
The solution for this case is to wrap literal relationals in
parentheses:
>>> e == (x < 1)
True
>>> e != (x < 1)
False
>>> (x < 1) != (x < 1)
False
The third gotcha involves chained inequalities not involving
``==`` or ``!=``. Occasionally, one may be tempted to write:
>>> e = x < y < z
Traceback (most recent call last):
...
TypeError: symbolic boolean expression has no truth value.
Due to an implementation detail or decision of Python [1]_,
there is no way for SymPy to create a chained inequality with
that syntax so one must use And:
>>> e = And(x < y, y < z)
>>> type( e )
And
>>> e
(x < y) & (y < z)
Although this can also be done with the '&' operator, it cannot
be done with the 'and' operarator:
>>> (x < y) & (y < z)
(x < y) & (y < z)
>>> (x < y) and (y < z)
Traceback (most recent call last):
...
TypeError: cannot determine truth value of Relational
.. [1] This implementation detail is that Python provides no reliable
method to determine that a chained inequality is being built.
Chained comparison operators are evaluated pairwise, using "and"
logic (see
https://docs.python.org/3/reference/expressions.html#not-in). This
is done in an efficient way, so that each object being compared
is only evaluated once and the comparison can short-circuit. For
example, ``1 > 2 > 3`` is evaluated by Python as ``(1 > 2) and (2
> 3)``. The ``and`` operator coerces each side into a bool,
returning the object itself when it short-circuits. The bool of
the --Than operators will raise TypeError on purpose, because
SymPy cannot determine the mathematical ordering of symbolic
expressions. Thus, if we were to compute ``x > y > z``, with
``x``, ``y``, and ``z`` being Symbols, Python converts the
statement (roughly) into these steps:
(1) x > y > z
(2) (x > y) and (y > z)
(3) (GreaterThanObject) and (y > z)
(4) (GreaterThanObject.__bool__()) and (y > z)
(5) TypeError
Because of the ``and`` added at step 2, the statement gets turned into a
weak ternary statement, and the first object's ``__bool__`` method will
raise TypeError. Thus, creating a chained inequality is not possible.
In Python, there is no way to override the ``and`` operator, or to
control how it short circuits, so it is impossible to make something
like ``x > y > z`` work. There was a PEP to change this,
:pep:`335`, but it was officially closed in March, 2012.
"""
__slots__ = ()
rel_op = '>='
@classmethod
def _eval_fuzzy_relation(cls, lhs, rhs):
return is_ge(lhs, rhs)
@property
def strict(self):
return Gt(*self.args)
Ge = GreaterThan
class LessThan(_Less):
__doc__ = GreaterThan.__doc__
__slots__ = ()
rel_op = '<='
@classmethod
def _eval_fuzzy_relation(cls, lhs, rhs):
return is_le(lhs, rhs)
@property
def strict(self):
return Lt(*self.args)
Le = LessThan
class StrictGreaterThan(_Greater):
__doc__ = GreaterThan.__doc__
__slots__ = ()
rel_op = '>'
@classmethod
def _eval_fuzzy_relation(cls, lhs, rhs):
return is_gt(lhs, rhs)
@property
def weak(self):
return Ge(*self.args)
Gt = StrictGreaterThan
class StrictLessThan(_Less):
__doc__ = GreaterThan.__doc__
__slots__ = ()
rel_op = '<'
@classmethod
def _eval_fuzzy_relation(cls, lhs, rhs):
return is_lt(lhs, rhs)
@property
def weak(self):
return Le(*self.args)
Lt = StrictLessThan
# A class-specific (not object-specific) data item used for a minor speedup.
# It is defined here, rather than directly in the class, because the classes
# that it references have not been defined until now (e.g. StrictLessThan).
Relational.ValidRelationOperator = {
None: Equality,
'==': Equality,
'eq': Equality,
'!=': Unequality,
'<>': Unequality,
'ne': Unequality,
'>=': GreaterThan,
'ge': GreaterThan,
'<=': LessThan,
'le': LessThan,
'>': StrictGreaterThan,
'gt': StrictGreaterThan,
'<': StrictLessThan,
'lt': StrictLessThan,
}
def _n2(a, b):
"""Return (a - b).evalf(2) if a and b are comparable, else None.
This should only be used when a and b are already sympified.
"""
# /!\ it is very important (see issue 8245) not to
# use a re-evaluated number in the calculation of dif
if a.is_comparable and b.is_comparable:
dif = (a - b).evalf(2)
if dif.is_comparable:
return dif
@dispatch(Expr, Expr)
def _eval_is_ge(lhs, rhs):
return None
@dispatch(Basic, Basic)
def _eval_is_eq(lhs, rhs):
return None
@dispatch(Tuple, Expr) # type: ignore
def _eval_is_eq(lhs, rhs): # noqa:F811
return False
@dispatch(Tuple, AppliedUndef) # type: ignore
def _eval_is_eq(lhs, rhs): # noqa:F811
return None
@dispatch(Tuple, Symbol) # type: ignore
def _eval_is_eq(lhs, rhs): # noqa:F811
return None
@dispatch(Tuple, Tuple) # type: ignore
def _eval_is_eq(lhs, rhs): # noqa:F811
if len(lhs) != len(rhs):
return False
return fuzzy_and(fuzzy_bool(is_eq(s, o)) for s, o in zip(lhs, rhs))
def is_lt(lhs, rhs, assumptions=None):
"""Fuzzy bool for lhs is strictly less than rhs.
See the docstring for :func:`~.is_ge` for more.
"""
return fuzzy_not(is_ge(lhs, rhs, assumptions))
def is_gt(lhs, rhs, assumptions=None):
"""Fuzzy bool for lhs is strictly greater than rhs.
See the docstring for :func:`~.is_ge` for more.
"""
return fuzzy_not(is_le(lhs, rhs, assumptions))
def is_le(lhs, rhs, assumptions=None):
"""Fuzzy bool for lhs is less than or equal to rhs.
See the docstring for :func:`~.is_ge` for more.
"""
return is_ge(rhs, lhs, assumptions)
def is_ge(lhs, rhs, assumptions=None):
"""
Fuzzy bool for *lhs* is greater than or equal to *rhs*.
Parameters
==========
lhs : Expr
The left-hand side of the expression, must be sympified,
and an instance of expression. Throws an exception if
lhs is not an instance of expression.
rhs : Expr
The right-hand side of the expression, must be sympified
and an instance of expression. Throws an exception if
lhs is not an instance of expression.
assumptions: Boolean, optional
Assumptions taken to evaluate the inequality.
Returns
=======
``True`` if *lhs* is greater than or equal to *rhs*, ``False`` if *lhs*
is less than *rhs*, and ``None`` if the comparison between *lhs* and
*rhs* is indeterminate.
Explanation
===========
This function is intended to give a relatively fast determination and
deliberately does not attempt slow calculations that might help in
obtaining a determination of True or False in more difficult cases.
The four comparison functions ``is_le``, ``is_lt``, ``is_ge``, and ``is_gt`` are
each implemented in terms of ``is_ge`` in the following way:
is_ge(x, y) := is_ge(x, y)
is_le(x, y) := is_ge(y, x)
is_lt(x, y) := fuzzy_not(is_ge(x, y))
is_gt(x, y) := fuzzy_not(is_ge(y, x))
Therefore, supporting new type with this function will ensure behavior for
other three functions as well.
To maintain these equivalences in fuzzy logic it is important that in cases where
either x or y is non-real all comparisons will give None.
Examples
========
>>> from sympy import S, Q
>>> from sympy.core.relational import is_ge, is_le, is_gt, is_lt
>>> from sympy.abc import x
>>> is_ge(S(2), S(0))
True
>>> is_ge(S(0), S(2))
False
>>> is_le(S(0), S(2))
True
>>> is_gt(S(0), S(2))
False
>>> is_lt(S(2), S(0))
False
Assumptions can be passed to evaluate the quality which is otherwise
indeterminate.
>>> print(is_ge(x, S(0)))
None
>>> is_ge(x, S(0), assumptions=Q.positive(x))
True
New types can be supported by dispatching to ``_eval_is_ge``.
>>> from sympy import Expr, sympify
>>> from sympy.multipledispatch import dispatch
>>> class MyExpr(Expr):
... def __new__(cls, arg):
... return super().__new__(cls, sympify(arg))
... @property
... def value(self):
... return self.args[0]
>>> @dispatch(MyExpr, MyExpr)
... def _eval_is_ge(a, b):
... return is_ge(a.value, b.value)
>>> a = MyExpr(1)
>>> b = MyExpr(2)
>>> is_ge(b, a)
True
>>> is_le(a, b)
True
"""
from sympy.assumptions.wrapper import AssumptionsWrapper, is_extended_nonnegative
if not (isinstance(lhs, Expr) and isinstance(rhs, Expr)):
raise TypeError("Can only compare inequalities with Expr")
retval = _eval_is_ge(lhs, rhs)
if retval is not None:
return retval
else:
n2 = _n2(lhs, rhs)
if n2 is not None:
# use float comparison for infinity.
# otherwise get stuck in infinite recursion
if n2 in (S.Infinity, S.NegativeInfinity):
n2 = float(n2)
return n2 >= 0
_lhs = AssumptionsWrapper(lhs, assumptions)
_rhs = AssumptionsWrapper(rhs, assumptions)
if _lhs.is_extended_real and _rhs.is_extended_real:
if (_lhs.is_infinite and _lhs.is_extended_positive) or (_rhs.is_infinite and _rhs.is_extended_negative):
return True
diff = lhs - rhs
if diff is not S.NaN:
rv = is_extended_nonnegative(diff, assumptions)
if rv is not None:
return rv
def is_neq(lhs, rhs, assumptions=None):
"""Fuzzy bool for lhs does not equal rhs.
See the docstring for :func:`~.is_eq` for more.
"""
return fuzzy_not(is_eq(lhs, rhs, assumptions))
def is_eq(lhs, rhs, assumptions=None):
"""
Fuzzy bool representing mathematical equality between *lhs* and *rhs*.
Parameters
==========
lhs : Expr
The left-hand side of the expression, must be sympified.
rhs : Expr
The right-hand side of the expression, must be sympified.
assumptions: Boolean, optional
Assumptions taken to evaluate the equality.
Returns
=======
``True`` if *lhs* is equal to *rhs*, ``False`` is *lhs* is not equal to *rhs*,
and ``None`` if the comparison between *lhs* and *rhs* is indeterminate.
Explanation
===========
This function is intended to give a relatively fast determination and
deliberately does not attempt slow calculations that might help in
obtaining a determination of True or False in more difficult cases.
:func:`~.is_neq` calls this function to return its value, so supporting
new type with this function will ensure correct behavior for ``is_neq``
as well.
Examples
========
>>> from sympy import Q, S
>>> from sympy.core.relational import is_eq, is_neq
>>> from sympy.abc import x
>>> is_eq(S(0), S(0))
True
>>> is_neq(S(0), S(0))
False
>>> is_eq(S(0), S(2))
False
>>> is_neq(S(0), S(2))
True
Assumptions can be passed to evaluate the equality which is otherwise
indeterminate.
>>> print(is_eq(x, S(0)))
None
>>> is_eq(x, S(0), assumptions=Q.zero(x))
True
New types can be supported by dispatching to ``_eval_is_eq``.
>>> from sympy import Basic, sympify
>>> from sympy.multipledispatch import dispatch
>>> class MyBasic(Basic):
... def __new__(cls, arg):
... return Basic.__new__(cls, sympify(arg))
... @property
... def value(self):
... return self.args[0]
...
>>> @dispatch(MyBasic, MyBasic)
... def _eval_is_eq(a, b):
... return is_eq(a.value, b.value)
...
>>> a = MyBasic(1)
>>> b = MyBasic(1)
>>> is_eq(a, b)
True
>>> is_neq(a, b)
False
"""
# here, _eval_Eq is only called for backwards compatibility
# new code should use is_eq with multiple dispatch as
# outlined in the docstring
for side1, side2 in (lhs, rhs), (rhs, lhs):
eval_func = getattr(side1, '_eval_Eq', None)
if eval_func is not None:
retval = eval_func(side2)
if retval is not None:
return retval
retval = _eval_is_eq(lhs, rhs)
if retval is not None:
return retval
if dispatch(type(lhs), type(rhs)) != dispatch(type(rhs), type(lhs)):
retval = _eval_is_eq(rhs, lhs)
if retval is not None:
return retval
# retval is still None, so go through the equality logic
# If expressions have the same structure, they must be equal.
if lhs == rhs:
return True # e.g. True == True
elif all(isinstance(i, BooleanAtom) for i in (rhs, lhs)):
return False # True != False
elif not (lhs.is_Symbol or rhs.is_Symbol) and (
isinstance(lhs, Boolean) !=
isinstance(rhs, Boolean)):
return False # only Booleans can equal Booleans
from sympy.assumptions.wrapper import (AssumptionsWrapper,
is_infinite, is_extended_real)
from .add import Add
_lhs = AssumptionsWrapper(lhs, assumptions)
_rhs = AssumptionsWrapper(rhs, assumptions)
if _lhs.is_infinite or _rhs.is_infinite:
if fuzzy_xor([_lhs.is_infinite, _rhs.is_infinite]):
return False
if fuzzy_xor([_lhs.is_extended_real, _rhs.is_extended_real]):
return False
if fuzzy_and([_lhs.is_extended_real, _rhs.is_extended_real]):
return fuzzy_xor([_lhs.is_extended_positive, fuzzy_not(_rhs.is_extended_positive)])
# Try to split real/imaginary parts and equate them
I = S.ImaginaryUnit
def split_real_imag(expr):
real_imag = lambda t: (
'real' if is_extended_real(t, assumptions) else
'imag' if is_extended_real(I*t, assumptions) else None)
return sift(Add.make_args(expr), real_imag)
lhs_ri = split_real_imag(lhs)
if not lhs_ri[None]:
rhs_ri = split_real_imag(rhs)
if not rhs_ri[None]:
eq_real = is_eq(Add(*lhs_ri['real']), Add(*rhs_ri['real']), assumptions)
eq_imag = is_eq(I * Add(*lhs_ri['imag']), I * Add(*rhs_ri['imag']), assumptions)
return fuzzy_and(map(fuzzy_bool, [eq_real, eq_imag]))
from sympy.functions.elementary.complexes import arg
# Compare e.g. zoo with 1+I*oo by comparing args
arglhs = arg(lhs)
argrhs = arg(rhs)
# Guard against Eq(nan, nan) -> False
if not (arglhs == S.NaN and argrhs == S.NaN):
return fuzzy_bool(is_eq(arglhs, argrhs, assumptions))
if all(isinstance(i, Expr) for i in (lhs, rhs)):
# see if the difference evaluates
dif = lhs - rhs
_dif = AssumptionsWrapper(dif, assumptions)
z = _dif.is_zero
if z is not None:
if z is False and _dif.is_commutative: # issue 10728
return False
if z:
return True
# is_zero cannot help decide integer/rational with Float
c, t = dif.as_coeff_Add()
if c.is_Float:
if int_valued(c):
if t.is_integer is False:
return False
elif t.is_rational is False:
return False
n2 = _n2(lhs, rhs)
if n2 is not None:
return _sympify(n2 == 0)
# see if the ratio evaluates
n, d = dif.as_numer_denom()
rv = None
_n = AssumptionsWrapper(n, assumptions)
_d = AssumptionsWrapper(d, assumptions)
if _n.is_zero:
rv = _d.is_nonzero
elif _n.is_finite:
if _d.is_infinite:
rv = True
elif _n.is_zero is False:
rv = _d.is_infinite
if rv is None:
# if the condition that makes the denominator
# infinite does not make the original expression
# True then False can be returned
from sympy.simplify.simplify import clear_coefficients
l, r = clear_coefficients(d, S.Infinity)
args = [_.subs(l, r) for _ in (lhs, rhs)]
if args != [lhs, rhs]:
rv = fuzzy_bool(is_eq(*args, assumptions))
if rv is True:
rv = None
elif any(is_infinite(a, assumptions) for a in Add.make_args(n)):
# (inf or nan)/x != 0
rv = False
if rv is not None:
return rv
PK ]ZZZ�� �� � sympy/core/rules.py"""
Replacement rules.
"""
class Transform:
"""
Immutable mapping that can be used as a generic transformation rule.
Parameters
==========
transform : callable
Computes the value corresponding to any key.
filter : callable, optional
If supplied, specifies which objects are in the mapping.
Examples
========
>>> from sympy.core.rules import Transform
>>> from sympy.abc import x
This Transform will return, as a value, one more than the key:
>>> add1 = Transform(lambda x: x + 1)
>>> add1[1]
2
>>> add1[x]
x + 1
By default, all values are considered to be in the dictionary. If a filter
is supplied, only the objects for which it returns True are considered as
being in the dictionary:
>>> add1_odd = Transform(lambda x: x + 1, lambda x: x%2 == 1)
>>> 2 in add1_odd
False
>>> add1_odd.get(2, 0)
0
>>> 3 in add1_odd
True
>>> add1_odd[3]
4
>>> add1_odd.get(3, 0)
4
"""
def __init__(self, transform, filter=lambda x: True):
self._transform = transform
self._filter = filter
def __contains__(self, item):
return self._filter(item)
def __getitem__(self, key):
if self._filter(key):
return self._transform(key)
else:
raise KeyError(key)
def get(self, item, default=None):
if item in self:
return self[item]
else:
return default
PK ]ZZZ�w� � sympy/core/singleton.py"""Singleton mechanism"""
from .core import Registry
from .sympify import sympify
class SingletonRegistry(Registry):
"""
The registry for the singleton classes (accessible as ``S``).
Explanation
===========
This class serves as two separate things.
The first thing it is is the ``SingletonRegistry``. Several classes in
SymPy appear so often that they are singletonized, that is, using some
metaprogramming they are made so that they can only be instantiated once
(see the :class:`sympy.core.singleton.Singleton` class for details). For
instance, every time you create ``Integer(0)``, this will return the same
instance, :class:`sympy.core.numbers.Zero`. All singleton instances are
attributes of the ``S`` object, so ``Integer(0)`` can also be accessed as
``S.Zero``.
Singletonization offers two advantages: it saves memory, and it allows
fast comparison. It saves memory because no matter how many times the
singletonized objects appear in expressions in memory, they all point to
the same single instance in memory. The fast comparison comes from the
fact that you can use ``is`` to compare exact instances in Python
(usually, you need to use ``==`` to compare things). ``is`` compares
objects by memory address, and is very fast.
Examples
========
>>> from sympy import S, Integer
>>> a = Integer(0)
>>> a is S.Zero
True
For the most part, the fact that certain objects are singletonized is an
implementation detail that users should not need to worry about. In SymPy
library code, ``is`` comparison is often used for performance purposes
The primary advantage of ``S`` for end users is the convenient access to
certain instances that are otherwise difficult to type, like ``S.Half``
(instead of ``Rational(1, 2)``).
When using ``is`` comparison, make sure the argument is sympified. For
instance,
>>> x = 0
>>> x is S.Zero
False
This problem is not an issue when using ``==``, which is recommended for
most use-cases:
>>> 0 == S.Zero
True
The second thing ``S`` is is a shortcut for
:func:`sympy.core.sympify.sympify`. :func:`sympy.core.sympify.sympify` is
the function that converts Python objects such as ``int(1)`` into SymPy
objects such as ``Integer(1)``. It also converts the string form of an
expression into a SymPy expression, like ``sympify("x**2")`` ->
``Symbol("x")**2``. ``S(1)`` is the same thing as ``sympify(1)``
(basically, ``S.__call__`` has been defined to call ``sympify``).
This is for convenience, since ``S`` is a single letter. It's mostly
useful for defining rational numbers. Consider an expression like ``x +
1/2``. If you enter this directly in Python, it will evaluate the ``1/2``
and give ``0.5``, because both arguments are ints (see also
:ref:`tutorial-gotchas-final-notes`). However, in SymPy, you usually want
the quotient of two integers to give an exact rational number. The way
Python's evaluation works, at least one side of an operator needs to be a
SymPy object for the SymPy evaluation to take over. You could write this
as ``x + Rational(1, 2)``, but this is a lot more typing. A shorter
version is ``x + S(1)/2``. Since ``S(1)`` returns ``Integer(1)``, the
division will return a ``Rational`` type, since it will call
``Integer.__truediv__``, which knows how to return a ``Rational``.
"""
__slots__ = ()
# Also allow things like S(5)
__call__ = staticmethod(sympify)
def __init__(self):
self._classes_to_install = {}
# Dict of classes that have been registered, but that have not have been
# installed as an attribute of this SingletonRegistry.
# Installation automatically happens at the first attempt to access the
# attribute.
# The purpose of this is to allow registration during class
# initialization during import, but not trigger object creation until
# actual use (which should not happen until after all imports are
# finished).
def register(self, cls):
# Make sure a duplicate class overwrites the old one
if hasattr(self, cls.__name__):
delattr(self, cls.__name__)
self._classes_to_install[cls.__name__] = cls
def __getattr__(self, name):
"""Python calls __getattr__ if no attribute of that name was installed
yet.
Explanation
===========
This __getattr__ checks whether a class with the requested name was
already registered but not installed; if no, raises an AttributeError.
Otherwise, retrieves the class, calculates its singleton value, installs
it as an attribute of the given name, and unregisters the class."""
if name not in self._classes_to_install:
raise AttributeError(
"Attribute '%s' was not installed on SymPy registry %s" % (
name, self))
class_to_install = self._classes_to_install[name]
value_to_install = class_to_install()
self.__setattr__(name, value_to_install)
del self._classes_to_install[name]
return value_to_install
def __repr__(self):
return "S"
S = SingletonRegistry()
class Singleton(type):
"""
Metaclass for singleton classes.
Explanation
===========
A singleton class has only one instance which is returned every time the
class is instantiated. Additionally, this instance can be accessed through
the global registry object ``S`` as ``S.<class_name>``.
Examples
========
>>> from sympy import S, Basic
>>> from sympy.core.singleton import Singleton
>>> class MySingleton(Basic, metaclass=Singleton):
... pass
>>> Basic() is Basic()
False
>>> MySingleton() is MySingleton()
True
>>> S.MySingleton is MySingleton()
True
Notes
=====
Instance creation is delayed until the first time the value is accessed.
(SymPy versions before 1.0 would create the instance during class
creation time, which would be prone to import cycles.)
"""
def __init__(cls, *args, **kwargs):
cls._instance = obj = Basic.__new__(cls)
cls.__new__ = lambda cls: obj
cls.__getnewargs__ = lambda obj: ()
cls.__getstate__ = lambda obj: None
S.register(cls)
# Delayed to avoid cyclic import
from .basic import Basic
PK ]ZZZ�.�K* K* sympy/core/sorting.pyfrom collections import defaultdict
from .sympify import sympify, SympifyError
from sympy.utilities.iterables import iterable, uniq
__all__ = ['default_sort_key', 'ordered']
def default_sort_key(item, order=None):
"""Return a key that can be used for sorting.
The key has the structure:
(class_key, (len(args), args), exponent.sort_key(), coefficient)
This key is supplied by the sort_key routine of Basic objects when
``item`` is a Basic object or an object (other than a string) that
sympifies to a Basic object. Otherwise, this function produces the
key.
The ``order`` argument is passed along to the sort_key routine and is
used to determine how the terms *within* an expression are ordered.
(See examples below) ``order`` options are: 'lex', 'grlex', 'grevlex',
and reversed values of the same (e.g. 'rev-lex'). The default order
value is None (which translates to 'lex').
Examples
========
>>> from sympy import S, I, default_sort_key, sin, cos, sqrt
>>> from sympy.core.function import UndefinedFunction
>>> from sympy.abc import x
The following are equivalent ways of getting the key for an object:
>>> x.sort_key() == default_sort_key(x)
True
Here are some examples of the key that is produced:
>>> default_sort_key(UndefinedFunction('f'))
((0, 0, 'UndefinedFunction'), (1, ('f',)), ((1, 0, 'Number'),
(0, ()), (), 1), 1)
>>> default_sort_key('1')
((0, 0, 'str'), (1, ('1',)), ((1, 0, 'Number'), (0, ()), (), 1), 1)
>>> default_sort_key(S.One)
((1, 0, 'Number'), (0, ()), (), 1)
>>> default_sort_key(2)
((1, 0, 'Number'), (0, ()), (), 2)
While sort_key is a method only defined for SymPy objects,
default_sort_key will accept anything as an argument so it is
more robust as a sorting key. For the following, using key=
lambda i: i.sort_key() would fail because 2 does not have a sort_key
method; that's why default_sort_key is used. Note, that it also
handles sympification of non-string items likes ints:
>>> a = [2, I, -I]
>>> sorted(a, key=default_sort_key)
[2, -I, I]
The returned key can be used anywhere that a key can be specified for
a function, e.g. sort, min, max, etc...:
>>> a.sort(key=default_sort_key); a[0]
2
>>> min(a, key=default_sort_key)
2
Notes
=====
The key returned is useful for getting items into a canonical order
that will be the same across platforms. It is not directly useful for
sorting lists of expressions:
>>> a, b = x, 1/x
Since ``a`` has only 1 term, its value of sort_key is unaffected by
``order``:
>>> a.sort_key() == a.sort_key('rev-lex')
True
If ``a`` and ``b`` are combined then the key will differ because there
are terms that can be ordered:
>>> eq = a + b
>>> eq.sort_key() == eq.sort_key('rev-lex')
False
>>> eq.as_ordered_terms()
[x, 1/x]
>>> eq.as_ordered_terms('rev-lex')
[1/x, x]
But since the keys for each of these terms are independent of ``order``'s
value, they do not sort differently when they appear separately in a list:
>>> sorted(eq.args, key=default_sort_key)
[1/x, x]
>>> sorted(eq.args, key=lambda i: default_sort_key(i, order='rev-lex'))
[1/x, x]
The order of terms obtained when using these keys is the order that would
be obtained if those terms were *factors* in a product.
Although it is useful for quickly putting expressions in canonical order,
it does not sort expressions based on their complexity defined by the
number of operations, power of variables and others:
>>> sorted([sin(x)*cos(x), sin(x)], key=default_sort_key)
[sin(x)*cos(x), sin(x)]
>>> sorted([x, x**2, sqrt(x), x**3], key=default_sort_key)
[sqrt(x), x, x**2, x**3]
See Also
========
ordered, sympy.core.expr.Expr.as_ordered_factors, sympy.core.expr.Expr.as_ordered_terms
"""
from .basic import Basic
from .singleton import S
if isinstance(item, Basic):
return item.sort_key(order=order)
if iterable(item, exclude=str):
if isinstance(item, dict):
args = item.items()
unordered = True
elif isinstance(item, set):
args = item
unordered = True
else:
# e.g. tuple, list
args = list(item)
unordered = False
args = [default_sort_key(arg, order=order) for arg in args]
if unordered:
# e.g. dict, set
args = sorted(args)
cls_index, args = 10, (len(args), tuple(args))
else:
if not isinstance(item, str):
try:
item = sympify(item, strict=True)
except SympifyError:
# e.g. lambda x: x
pass
else:
if isinstance(item, Basic):
# e.g int -> Integer
return default_sort_key(item)
# e.g. UndefinedFunction
# e.g. str
cls_index, args = 0, (1, (str(item),))
return (cls_index, 0, item.__class__.__name__
), args, S.One.sort_key(), S.One
def _node_count(e):
# this not only counts nodes, it affirms that the
# args are Basic (i.e. have an args property). If
# some object has a non-Basic arg, it needs to be
# fixed since it is intended that all Basic args
# are of Basic type (though this is not easy to enforce).
if e.is_Float:
return 0.5
return 1 + sum(map(_node_count, e.args))
def _nodes(e):
"""
A helper for ordered() which returns the node count of ``e`` which
for Basic objects is the number of Basic nodes in the expression tree
but for other objects is 1 (unless the object is an iterable or dict
for which the sum of nodes is returned).
"""
from .basic import Basic
from .function import Derivative
if isinstance(e, Basic):
if isinstance(e, Derivative):
return _nodes(e.expr) + sum(i[1] if i[1].is_Number else
_nodes(i[1]) for i in e.variable_count)
return _node_count(e)
elif iterable(e):
return 1 + sum(_nodes(ei) for ei in e)
elif isinstance(e, dict):
return 1 + sum(_nodes(k) + _nodes(v) for k, v in e.items())
else:
return 1
def ordered(seq, keys=None, default=True, warn=False):
"""Return an iterator of the seq where keys are used to break ties
in a conservative fashion: if, after applying a key, there are no
ties then no other keys will be computed.
Two default keys will be applied if 1) keys are not provided or
2) the given keys do not resolve all ties (but only if ``default``
is True). The two keys are ``_nodes`` (which places smaller
expressions before large) and ``default_sort_key`` which (if the
``sort_key`` for an object is defined properly) should resolve
any ties. This strategy is similar to sorting done by
``Basic.compare``, but differs in that ``ordered`` never makes a
decision based on an objects name.
If ``warn`` is True then an error will be raised if there were no
keys remaining to break ties. This can be used if it was expected that
there should be no ties between items that are not identical.
Examples
========
>>> from sympy import ordered, count_ops
>>> from sympy.abc import x, y
The count_ops is not sufficient to break ties in this list and the first
two items appear in their original order (i.e. the sorting is stable):
>>> list(ordered([y + 2, x + 2, x**2 + y + 3],
... count_ops, default=False, warn=False))
...
[y + 2, x + 2, x**2 + y + 3]
The default_sort_key allows the tie to be broken:
>>> list(ordered([y + 2, x + 2, x**2 + y + 3]))
...
[x + 2, y + 2, x**2 + y + 3]
Here, sequences are sorted by length, then sum:
>>> seq, keys = [[[1, 2, 1], [0, 3, 1], [1, 1, 3], [2], [1]], [
... lambda x: len(x),
... lambda x: sum(x)]]
...
>>> list(ordered(seq, keys, default=False, warn=False))
[[1], [2], [1, 2, 1], [0, 3, 1], [1, 1, 3]]
If ``warn`` is True, an error will be raised if there were not
enough keys to break ties:
>>> list(ordered(seq, keys, default=False, warn=True))
Traceback (most recent call last):
...
ValueError: not enough keys to break ties
Notes
=====
The decorated sort is one of the fastest ways to sort a sequence for
which special item comparison is desired: the sequence is decorated,
sorted on the basis of the decoration (e.g. making all letters lower
case) and then undecorated. If one wants to break ties for items that
have the same decorated value, a second key can be used. But if the
second key is expensive to compute then it is inefficient to decorate
all items with both keys: only those items having identical first key
values need to be decorated. This function applies keys successively
only when needed to break ties. By yielding an iterator, use of the
tie-breaker is delayed as long as possible.
This function is best used in cases when use of the first key is
expected to be a good hashing function; if there are no unique hashes
from application of a key, then that key should not have been used. The
exception, however, is that even if there are many collisions, if the
first group is small and one does not need to process all items in the
list then time will not be wasted sorting what one was not interested
in. For example, if one were looking for the minimum in a list and
there were several criteria used to define the sort order, then this
function would be good at returning that quickly if the first group
of candidates is small relative to the number of items being processed.
"""
d = defaultdict(list)
if keys:
if isinstance(keys, (list, tuple)):
keys = list(keys)
f = keys.pop(0)
else:
f = keys
keys = []
for a in seq:
d[f(a)].append(a)
else:
if not default:
raise ValueError('if default=False then keys must be provided')
d[None].extend(seq)
for k, value in sorted(d.items()):
if len(value) > 1:
if keys:
value = ordered(value, keys, default, warn)
elif default:
value = ordered(value, (_nodes, default_sort_key,),
default=False, warn=warn)
elif warn:
u = list(uniq(value))
if len(u) > 1:
raise ValueError(
'not enough keys to break ties: %s' % u)
yield from value
PK ]ZZZw��#)s )s sympy/core/symbol.pyfrom __future__ import annotations
from .assumptions import StdFactKB, _assume_defined
from .basic import Basic, Atom
from .cache import cacheit
from .containers import Tuple
from .expr import Expr, AtomicExpr
from .function import AppliedUndef, FunctionClass
from .kind import NumberKind, UndefinedKind
from .logic import fuzzy_bool
from .singleton import S
from .sorting import ordered
from .sympify import sympify
from sympy.logic.boolalg import Boolean
from sympy.utilities.iterables import sift, is_sequence
from sympy.utilities.misc import filldedent
import string
import re as _re
import random
from itertools import product
from typing import Any
class Str(Atom):
"""
Represents string in SymPy.
Explanation
===========
Previously, ``Symbol`` was used where string is needed in ``args`` of SymPy
objects, e.g. denoting the name of the instance. However, since ``Symbol``
represents mathematical scalar, this class should be used instead.
"""
__slots__ = ('name',)
def __new__(cls, name, **kwargs):
if not isinstance(name, str):
raise TypeError("name should be a string, not %s" % repr(type(name)))
obj = Expr.__new__(cls, **kwargs)
obj.name = name
return obj
def __getnewargs__(self):
return (self.name,)
def _hashable_content(self):
return (self.name,)
def _filter_assumptions(kwargs):
"""Split the given dict into assumptions and non-assumptions.
Keys are taken as assumptions if they correspond to an
entry in ``_assume_defined``.
"""
assumptions, nonassumptions = map(dict, sift(kwargs.items(),
lambda i: i[0] in _assume_defined,
binary=True))
Symbol._sanitize(assumptions)
return assumptions, nonassumptions
def _symbol(s, matching_symbol=None, **assumptions):
"""Return s if s is a Symbol, else if s is a string, return either
the matching_symbol if the names are the same or else a new symbol
with the same assumptions as the matching symbol (or the
assumptions as provided).
Examples
========
>>> from sympy import Symbol
>>> from sympy.core.symbol import _symbol
>>> _symbol('y')
y
>>> _.is_real is None
True
>>> _symbol('y', real=True).is_real
True
>>> x = Symbol('x')
>>> _symbol(x, real=True)
x
>>> _.is_real is None # ignore attribute if s is a Symbol
True
Below, the variable sym has the name 'foo':
>>> sym = Symbol('foo', real=True)
Since 'x' is not the same as sym's name, a new symbol is created:
>>> _symbol('x', sym).name
'x'
It will acquire any assumptions give:
>>> _symbol('x', sym, real=False).is_real
False
Since 'foo' is the same as sym's name, sym is returned
>>> _symbol('foo', sym)
foo
Any assumptions given are ignored:
>>> _symbol('foo', sym, real=False).is_real
True
NB: the symbol here may not be the same as a symbol with the same
name defined elsewhere as a result of different assumptions.
See Also
========
sympy.core.symbol.Symbol
"""
if isinstance(s, str):
if matching_symbol and matching_symbol.name == s:
return matching_symbol
return Symbol(s, **assumptions)
elif isinstance(s, Symbol):
return s
else:
raise ValueError('symbol must be string for symbol name or Symbol')
def uniquely_named_symbol(xname, exprs=(), compare=str, modify=None, **assumptions):
"""
Return a symbol whose name is derivated from *xname* but is unique
from any other symbols in *exprs*.
*xname* and symbol names in *exprs* are passed to *compare* to be
converted to comparable forms. If ``compare(xname)`` is not unique,
it is recursively passed to *modify* until unique name is acquired.
Parameters
==========
xname : str or Symbol
Base name for the new symbol.
exprs : Expr or iterable of Expr
Expressions whose symbols are compared to *xname*.
compare : function
Unary function which transforms *xname* and symbol names from
*exprs* to comparable form.
modify : function
Unary function which modifies the string. Default is appending
the number, or increasing the number if exists.
Examples
========
By default, a number is appended to *xname* to generate unique name.
If the number already exists, it is recursively increased.
>>> from sympy.core.symbol import uniquely_named_symbol, Symbol
>>> uniquely_named_symbol('x', Symbol('x'))
x0
>>> uniquely_named_symbol('x', (Symbol('x'), Symbol('x0')))
x1
>>> uniquely_named_symbol('x0', (Symbol('x1'), Symbol('x0')))
x2
Name generation can be controlled by passing *modify* parameter.
>>> from sympy.abc import x
>>> uniquely_named_symbol('x', x, modify=lambda s: 2*s)
xx
"""
def numbered_string_incr(s, start=0):
if not s:
return str(start)
i = len(s) - 1
while i != -1:
if not s[i].isdigit():
break
i -= 1
n = str(int(s[i + 1:] or start - 1) + 1)
return s[:i + 1] + n
default = None
if is_sequence(xname):
xname, default = xname
x = compare(xname)
if not exprs:
return _symbol(x, default, **assumptions)
if not is_sequence(exprs):
exprs = [exprs]
names = set().union(
[i.name for e in exprs for i in e.atoms(Symbol)] +
[i.func.name for e in exprs for i in e.atoms(AppliedUndef)])
if modify is None:
modify = numbered_string_incr
while any(x == compare(s) for s in names):
x = modify(x)
return _symbol(x, default, **assumptions)
_uniquely_named_symbol = uniquely_named_symbol
class Symbol(AtomicExpr, Boolean):
"""
Symbol class is used to create symbolic variables.
Explanation
===========
Symbolic variables are placeholders for mathematical symbols that can represent numbers, constants, or any other mathematical entities and can be used in mathematical expressions and to perform symbolic computations.
Assumptions:
commutative = True
positive = True
real = True
imaginary = True
complex = True
complete list of more assumptions- :ref:`predicates`
You can override the default assumptions in the constructor.
Examples
========
>>> from sympy import Symbol
>>> x = Symbol("x", positive=True)
>>> x.is_positive
True
>>> x.is_negative
False
passing in greek letters:
>>> from sympy import Symbol
>>> alpha = Symbol('alpha')
>>> alpha #doctest: +SKIP
α
Trailing digits are automatically treated like subscripts of what precedes them in the name.
General format to add subscript to a symbol :
``<var_name> = Symbol('<symbol_name>_<subscript>')``
>>> from sympy import Symbol
>>> alpha_i = Symbol('alpha_i')
>>> alpha_i #doctest: +SKIP
αᵢ
Parameters
==========
AtomicExpr: variable name
Boolean: Assumption with a boolean value(True or False)
"""
is_comparable = False
__slots__ = ('name', '_assumptions_orig', '_assumptions0')
name: str
is_Symbol = True
is_symbol = True
@property
def kind(self):
if self.is_commutative:
return NumberKind
return UndefinedKind
@property
def _diff_wrt(self):
"""Allow derivatives wrt Symbols.
Examples
========
>>> from sympy import Symbol
>>> x = Symbol('x')
>>> x._diff_wrt
True
"""
return True
@staticmethod
def _sanitize(assumptions, obj=None):
"""Remove None, convert values to bool, check commutativity *in place*.
"""
# be strict about commutativity: cannot be None
is_commutative = fuzzy_bool(assumptions.get('commutative', True))
if is_commutative is None:
whose = '%s ' % obj.__name__ if obj else ''
raise ValueError(
'%scommutativity must be True or False.' % whose)
# sanitize other assumptions so 1 -> True and 0 -> False
for key in list(assumptions.keys()):
v = assumptions[key]
if v is None:
assumptions.pop(key)
continue
assumptions[key] = bool(v)
def _merge(self, assumptions):
base = self.assumptions0
for k in set(assumptions) & set(base):
if assumptions[k] != base[k]:
raise ValueError(filldedent('''
non-matching assumptions for %s: existing value
is %s and new value is %s''' % (
k, base[k], assumptions[k])))
base.update(assumptions)
return base
def __new__(cls, name, **assumptions):
"""Symbols are identified by name and assumptions::
>>> from sympy import Symbol
>>> Symbol("x") == Symbol("x")
True
>>> Symbol("x", real=True) == Symbol("x", real=False)
False
"""
cls._sanitize(assumptions, cls)
return Symbol.__xnew_cached_(cls, name, **assumptions)
@staticmethod
def __xnew__(cls, name, **assumptions): # never cached (e.g. dummy)
if not isinstance(name, str):
raise TypeError("name should be a string, not %s" % repr(type(name)))
# This is retained purely so that srepr can include commutative=True if
# that was explicitly specified but not if it was not. Ideally srepr
# should not distinguish these cases because the symbols otherwise
# compare equal and are considered equivalent.
#
# See https://github.com/sympy/sympy/issues/8873
#
assumptions_orig = assumptions.copy()
# The only assumption that is assumed by default is comutative=True:
assumptions.setdefault('commutative', True)
assumptions_kb = StdFactKB(assumptions)
assumptions0 = dict(assumptions_kb)
obj = Expr.__new__(cls)
obj.name = name
obj._assumptions = assumptions_kb
obj._assumptions_orig = assumptions_orig
obj._assumptions0 = assumptions0
# The three assumptions dicts are all a little different:
#
# >>> from sympy import Symbol
# >>> x = Symbol('x', finite=True)
# >>> x.is_positive # query an assumption
# >>> x._assumptions
# {'finite': True, 'infinite': False, 'commutative': True, 'positive': None}
# >>> x._assumptions0
# {'finite': True, 'infinite': False, 'commutative': True}
# >>> x._assumptions_orig
# {'finite': True}
#
# Two symbols with the same name are equal if their _assumptions0 are
# the same. Arguably it should be _assumptions_orig that is being
# compared because that is more transparent to the user (it is
# what was passed to the constructor modulo changes made by _sanitize).
return obj
@staticmethod
@cacheit
def __xnew_cached_(cls, name, **assumptions): # symbols are always cached
return Symbol.__xnew__(cls, name, **assumptions)
def __getnewargs_ex__(self):
return ((self.name,), self._assumptions_orig)
# NOTE: __setstate__ is not needed for pickles created by __getnewargs_ex__
# but was used before Symbol was changed to use __getnewargs_ex__ in v1.9.
# Pickles created in previous SymPy versions will still need __setstate__
# so that they can be unpickled in SymPy > v1.9.
def __setstate__(self, state):
for name, value in state.items():
setattr(self, name, value)
def _hashable_content(self):
# Note: user-specified assumptions not hashed, just derived ones
return (self.name,) + tuple(sorted(self.assumptions0.items()))
def _eval_subs(self, old, new):
if old.is_Pow:
from sympy.core.power import Pow
return Pow(self, S.One, evaluate=False)._eval_subs(old, new)
def _eval_refine(self, assumptions):
return self
@property
def assumptions0(self):
return self._assumptions0.copy()
@cacheit
def sort_key(self, order=None):
return self.class_key(), (1, (self.name,)), S.One.sort_key(), S.One
def as_dummy(self):
# only put commutativity in explicitly if it is False
return Dummy(self.name) if self.is_commutative is not False \
else Dummy(self.name, commutative=self.is_commutative)
def as_real_imag(self, deep=True, **hints):
if hints.get('ignore') == self:
return None
else:
from sympy.functions.elementary.complexes import im, re
return (re(self), im(self))
def is_constant(self, *wrt, **flags):
if not wrt:
return False
return self not in wrt
@property
def free_symbols(self):
return {self}
binary_symbols = free_symbols # in this case, not always
def as_set(self):
return S.UniversalSet
class Dummy(Symbol):
"""Dummy symbols are each unique, even if they have the same name:
Examples
========
>>> from sympy import Dummy
>>> Dummy("x") == Dummy("x")
False
If a name is not supplied then a string value of an internal count will be
used. This is useful when a temporary variable is needed and the name
of the variable used in the expression is not important.
>>> Dummy() #doctest: +SKIP
_Dummy_10
"""
# In the rare event that a Dummy object needs to be recreated, both the
# `name` and `dummy_index` should be passed. This is used by `srepr` for
# example:
# >>> d1 = Dummy()
# >>> d2 = eval(srepr(d1))
# >>> d2 == d1
# True
#
# If a new session is started between `srepr` and `eval`, there is a very
# small chance that `d2` will be equal to a previously-created Dummy.
_count = 0
_prng = random.Random()
_base_dummy_index = _prng.randint(10**6, 9*10**6)
__slots__ = ('dummy_index',)
is_Dummy = True
def __new__(cls, name=None, dummy_index=None, **assumptions):
if dummy_index is not None:
assert name is not None, "If you specify a dummy_index, you must also provide a name"
if name is None:
name = "Dummy_" + str(Dummy._count)
if dummy_index is None:
dummy_index = Dummy._base_dummy_index + Dummy._count
Dummy._count += 1
cls._sanitize(assumptions, cls)
obj = Symbol.__xnew__(cls, name, **assumptions)
obj.dummy_index = dummy_index
return obj
def __getnewargs_ex__(self):
return ((self.name, self.dummy_index), self._assumptions_orig)
@cacheit
def sort_key(self, order=None):
return self.class_key(), (
2, (self.name, self.dummy_index)), S.One.sort_key(), S.One
def _hashable_content(self):
return Symbol._hashable_content(self) + (self.dummy_index,)
class Wild(Symbol):
"""
A Wild symbol matches anything, or anything
without whatever is explicitly excluded.
Parameters
==========
name : str
Name of the Wild instance.
exclude : iterable, optional
Instances in ``exclude`` will not be matched.
properties : iterable of functions, optional
Functions, each taking an expressions as input
and returns a ``bool``. All functions in ``properties``
need to return ``True`` in order for the Wild instance
to match the expression.
Examples
========
>>> from sympy import Wild, WildFunction, cos, pi
>>> from sympy.abc import x, y, z
>>> a = Wild('a')
>>> x.match(a)
{a_: x}
>>> pi.match(a)
{a_: pi}
>>> (3*x**2).match(a*x)
{a_: 3*x}
>>> cos(x).match(a)
{a_: cos(x)}
>>> b = Wild('b', exclude=[x])
>>> (3*x**2).match(b*x)
>>> b.match(a)
{a_: b_}
>>> A = WildFunction('A')
>>> A.match(a)
{a_: A_}
Tips
====
When using Wild, be sure to use the exclude
keyword to make the pattern more precise.
Without the exclude pattern, you may get matches
that are technically correct, but not what you
wanted. For example, using the above without
exclude:
>>> from sympy import symbols
>>> a, b = symbols('a b', cls=Wild)
>>> (2 + 3*y).match(a*x + b*y)
{a_: 2/x, b_: 3}
This is technically correct, because
(2/x)*x + 3*y == 2 + 3*y, but you probably
wanted it to not match at all. The issue is that
you really did not want a and b to include x and y,
and the exclude parameter lets you specify exactly
this. With the exclude parameter, the pattern will
not match.
>>> a = Wild('a', exclude=[x, y])
>>> b = Wild('b', exclude=[x, y])
>>> (2 + 3*y).match(a*x + b*y)
Exclude also helps remove ambiguity from matches.
>>> E = 2*x**3*y*z
>>> a, b = symbols('a b', cls=Wild)
>>> E.match(a*b)
{a_: 2*y*z, b_: x**3}
>>> a = Wild('a', exclude=[x, y])
>>> E.match(a*b)
{a_: z, b_: 2*x**3*y}
>>> a = Wild('a', exclude=[x, y, z])
>>> E.match(a*b)
{a_: 2, b_: x**3*y*z}
Wild also accepts a ``properties`` parameter:
>>> a = Wild('a', properties=[lambda k: k.is_Integer])
>>> E.match(a*b)
{a_: 2, b_: x**3*y*z}
"""
is_Wild = True
__slots__ = ('exclude', 'properties')
def __new__(cls, name, exclude=(), properties=(), **assumptions):
exclude = tuple([sympify(x) for x in exclude])
properties = tuple(properties)
cls._sanitize(assumptions, cls)
return Wild.__xnew__(cls, name, exclude, properties, **assumptions)
def __getnewargs__(self):
return (self.name, self.exclude, self.properties)
@staticmethod
@cacheit
def __xnew__(cls, name, exclude, properties, **assumptions):
obj = Symbol.__xnew__(cls, name, **assumptions)
obj.exclude = exclude
obj.properties = properties
return obj
def _hashable_content(self):
return super()._hashable_content() + (self.exclude, self.properties)
# TODO add check against another Wild
def matches(self, expr, repl_dict=None, old=False):
if any(expr.has(x) for x in self.exclude):
return None
if not all(f(expr) for f in self.properties):
return None
if repl_dict is None:
repl_dict = {}
else:
repl_dict = repl_dict.copy()
repl_dict[self] = expr
return repl_dict
_range = _re.compile('([0-9]*:[0-9]+|[a-zA-Z]?:[a-zA-Z])')
def symbols(names, *, cls=Symbol, **args) -> Any:
r"""
Transform strings into instances of :class:`Symbol` class.
:func:`symbols` function returns a sequence of symbols with names taken
from ``names`` argument, which can be a comma or whitespace delimited
string, or a sequence of strings::
>>> from sympy import symbols, Function
>>> x, y, z = symbols('x,y,z')
>>> a, b, c = symbols('a b c')
The type of output is dependent on the properties of input arguments::
>>> symbols('x')
x
>>> symbols('x,')
(x,)
>>> symbols('x,y')
(x, y)
>>> symbols(('a', 'b', 'c'))
(a, b, c)
>>> symbols(['a', 'b', 'c'])
[a, b, c]
>>> symbols({'a', 'b', 'c'})
{a, b, c}
If an iterable container is needed for a single symbol, set the ``seq``
argument to ``True`` or terminate the symbol name with a comma::
>>> symbols('x', seq=True)
(x,)
To reduce typing, range syntax is supported to create indexed symbols.
Ranges are indicated by a colon and the type of range is determined by
the character to the right of the colon. If the character is a digit
then all contiguous digits to the left are taken as the nonnegative
starting value (or 0 if there is no digit left of the colon) and all
contiguous digits to the right are taken as 1 greater than the ending
value::
>>> symbols('x:10')
(x0, x1, x2, x3, x4, x5, x6, x7, x8, x9)
>>> symbols('x5:10')
(x5, x6, x7, x8, x9)
>>> symbols('x5(:2)')
(x50, x51)
>>> symbols('x5:10,y:5')
(x5, x6, x7, x8, x9, y0, y1, y2, y3, y4)
>>> symbols(('x5:10', 'y:5'))
((x5, x6, x7, x8, x9), (y0, y1, y2, y3, y4))
If the character to the right of the colon is a letter, then the single
letter to the left (or 'a' if there is none) is taken as the start
and all characters in the lexicographic range *through* the letter to
the right are used as the range::
>>> symbols('x:z')
(x, y, z)
>>> symbols('x:c') # null range
()
>>> symbols('x(:c)')
(xa, xb, xc)
>>> symbols(':c')
(a, b, c)
>>> symbols('a:d, x:z')
(a, b, c, d, x, y, z)
>>> symbols(('a:d', 'x:z'))
((a, b, c, d), (x, y, z))
Multiple ranges are supported; contiguous numerical ranges should be
separated by parentheses to disambiguate the ending number of one
range from the starting number of the next::
>>> symbols('x:2(1:3)')
(x01, x02, x11, x12)
>>> symbols(':3:2') # parsing is from left to right
(00, 01, 10, 11, 20, 21)
Only one pair of parentheses surrounding ranges are removed, so to
include parentheses around ranges, double them. And to include spaces,
commas, or colons, escape them with a backslash::
>>> symbols('x((a:b))')
(x(a), x(b))
>>> symbols(r'x(:1\,:2)') # or r'x((:1)\,(:2))'
(x(0,0), x(0,1))
All newly created symbols have assumptions set according to ``args``::
>>> a = symbols('a', integer=True)
>>> a.is_integer
True
>>> x, y, z = symbols('x,y,z', real=True)
>>> x.is_real and y.is_real and z.is_real
True
Despite its name, :func:`symbols` can create symbol-like objects like
instances of Function or Wild classes. To achieve this, set ``cls``
keyword argument to the desired type::
>>> symbols('f,g,h', cls=Function)
(f, g, h)
>>> type(_[0])
<class 'sympy.core.function.UndefinedFunction'>
"""
result = []
if isinstance(names, str):
marker = 0
splitters = r'\,', r'\:', r'\ '
literals: list[tuple[str, str]] = []
for splitter in splitters:
if splitter in names:
while chr(marker) in names:
marker += 1
lit_char = chr(marker)
marker += 1
names = names.replace(splitter, lit_char)
literals.append((lit_char, splitter[1:]))
def literal(s):
if literals:
for c, l in literals:
s = s.replace(c, l)
return s
names = names.strip()
as_seq = names.endswith(',')
if as_seq:
names = names[:-1].rstrip()
if not names:
raise ValueError('no symbols given')
# split on commas
names = [n.strip() for n in names.split(',')]
if not all(n for n in names):
raise ValueError('missing symbol between commas')
# split on spaces
for i in range(len(names) - 1, -1, -1):
names[i: i + 1] = names[i].split()
seq = args.pop('seq', as_seq)
for name in names:
if not name:
raise ValueError('missing symbol')
if ':' not in name:
symbol = cls(literal(name), **args)
result.append(symbol)
continue
split: list[str] = _range.split(name)
split_list: list[list[str]] = []
# remove 1 layer of bounding parentheses around ranges
for i in range(len(split) - 1):
if i and ':' in split[i] and split[i] != ':' and \
split[i - 1].endswith('(') and \
split[i + 1].startswith(')'):
split[i - 1] = split[i - 1][:-1]
split[i + 1] = split[i + 1][1:]
for s in split:
if ':' in s:
if s.endswith(':'):
raise ValueError('missing end range')
a, b = s.split(':')
if b[-1] in string.digits:
a_i = 0 if not a else int(a)
b_i = int(b)
split_list.append([str(c) for c in range(a_i, b_i)])
else:
a = a or 'a'
split_list.append([string.ascii_letters[c] for c in range(
string.ascii_letters.index(a),
string.ascii_letters.index(b) + 1)]) # inclusive
if not split_list[-1]:
break
else:
split_list.append([s])
else:
seq = True
if len(split_list) == 1:
names = split_list[0]
else:
names = [''.join(s) for s in product(*split_list)]
if literals:
result.extend([cls(literal(s), **args) for s in names])
else:
result.extend([cls(s, **args) for s in names])
if not seq and len(result) <= 1:
if not result:
return ()
return result[0]
return tuple(result)
else:
for name in names:
result.append(symbols(name, cls=cls, **args))
return type(names)(result)
def var(names, **args):
"""
Create symbols and inject them into the global namespace.
Explanation
===========
This calls :func:`symbols` with the same arguments and puts the results
into the *global* namespace. It's recommended not to use :func:`var` in
library code, where :func:`symbols` has to be used::
Examples
========
>>> from sympy import var
>>> var('x')
x
>>> x # noqa: F821
x
>>> var('a,ab,abc')
(a, ab, abc)
>>> abc # noqa: F821
abc
>>> var('x,y', real=True)
(x, y)
>>> x.is_real and y.is_real # noqa: F821
True
See :func:`symbols` documentation for more details on what kinds of
arguments can be passed to :func:`var`.
"""
def traverse(symbols, frame):
"""Recursively inject symbols to the global namespace. """
for symbol in symbols:
if isinstance(symbol, Basic):
frame.f_globals[symbol.name] = symbol
elif isinstance(symbol, FunctionClass):
frame.f_globals[symbol.__name__] = symbol
else:
traverse(symbol, frame)
from inspect import currentframe
frame = currentframe().f_back
try:
syms = symbols(names, **args)
if syms is not None:
if isinstance(syms, Basic):
frame.f_globals[syms.name] = syms
elif isinstance(syms, FunctionClass):
frame.f_globals[syms.__name__] = syms
else:
traverse(syms, frame)
finally:
del frame # break cyclic dependencies as stated in inspect docs
return syms
def disambiguate(*iter):
"""
Return a Tuple containing the passed expressions with symbols
that appear the same when printed replaced with numerically
subscripted symbols, and all Dummy symbols replaced with Symbols.
Parameters
==========
iter: list of symbols or expressions.
Examples
========
>>> from sympy.core.symbol import disambiguate
>>> from sympy import Dummy, Symbol, Tuple
>>> from sympy.abc import y
>>> tup = Symbol('_x'), Dummy('x'), Dummy('x')
>>> disambiguate(*tup)
(x_2, x, x_1)
>>> eqs = Tuple(Symbol('x')/y, Dummy('x')/y)
>>> disambiguate(*eqs)
(x_1/y, x/y)
>>> ix = Symbol('x', integer=True)
>>> vx = Symbol('x')
>>> disambiguate(vx + ix)
(x + x_1,)
To make your own mapping of symbols to use, pass only the free symbols
of the expressions and create a dictionary:
>>> free = eqs.free_symbols
>>> mapping = dict(zip(free, disambiguate(*free)))
>>> eqs.xreplace(mapping)
(x_1/y, x/y)
"""
new_iter = Tuple(*iter)
key = lambda x:tuple(sorted(x.assumptions0.items()))
syms = ordered(new_iter.free_symbols, keys=key)
mapping = {}
for s in syms:
mapping.setdefault(str(s).lstrip('_'), []).append(s)
reps = {}
for k in mapping:
# the first or only symbol doesn't get subscripted but make
# sure that it's a Symbol, not a Dummy
mapk0 = Symbol("%s" % (k), **mapping[k][0].assumptions0)
if mapping[k][0] != mapk0:
reps[mapping[k][0]] = mapk0
# the others get subscripts (and are made into Symbols)
skip = 0
for i in range(1, len(mapping[k])):
while True:
name = "%s_%i" % (k, i + skip)
if name not in mapping:
break
skip += 1
ki = mapping[k][i]
reps[ki] = Symbol(name, **ki.assumptions0)
return new_iter.xreplace(reps)
PK ]ZZZ{��GQM QM sympy/core/sympify.py"""sympify -- convert objects SymPy internal format"""
from __future__ import annotations
from typing import Any, Callable
import mpmath.libmp as mlib
from inspect import getmro
import string
from sympy.core.random import choice
from .parameters import global_parameters
from sympy.utilities.iterables import iterable
class SympifyError(ValueError):
def __init__(self, expr, base_exc=None):
self.expr = expr
self.base_exc = base_exc
def __str__(self):
if self.base_exc is None:
return "SympifyError: %r" % (self.expr,)
return ("Sympify of expression '%s' failed, because of exception being "
"raised:\n%s: %s" % (self.expr, self.base_exc.__class__.__name__,
str(self.base_exc)))
converter: dict[type[Any], Callable[[Any], Basic]] = {}
#holds the conversions defined in SymPy itself, i.e. non-user defined conversions
_sympy_converter: dict[type[Any], Callable[[Any], Basic]] = {}
#alias for clearer use in the library
_external_converter = converter
class CantSympify:
"""
Mix in this trait to a class to disallow sympification of its instances.
Examples
========
>>> from sympy import sympify
>>> from sympy.core.sympify import CantSympify
>>> class Something(dict):
... pass
...
>>> sympify(Something())
{}
>>> class Something(dict, CantSympify):
... pass
...
>>> sympify(Something())
Traceback (most recent call last):
...
SympifyError: SympifyError: {}
"""
__slots__ = ()
def _is_numpy_instance(a):
"""
Checks if an object is an instance of a type from the numpy module.
"""
# This check avoids unnecessarily importing NumPy. We check the whole
# __mro__ in case any base type is a numpy type.
return any(type_.__module__ == 'numpy'
for type_ in type(a).__mro__)
def _convert_numpy_types(a, **sympify_args):
"""
Converts a numpy datatype input to an appropriate SymPy type.
"""
import numpy as np
if not isinstance(a, np.floating):
if np.iscomplex(a):
return _sympy_converter[complex](a.item())
else:
return sympify(a.item(), **sympify_args)
else:
from .numbers import Float
prec = np.finfo(a).nmant + 1
# E.g. double precision means prec=53 but nmant=52
# Leading bit of mantissa is always 1, so is not stored
p, q = a.as_integer_ratio()
a = mlib.from_rational(p, q, prec)
return Float(a, precision=prec)
def sympify(a, locals=None, convert_xor=True, strict=False, rational=False,
evaluate=None):
"""
Converts an arbitrary expression to a type that can be used inside SymPy.
Explanation
===========
It will convert Python ints into instances of :class:`~.Integer`, floats
into instances of :class:`~.Float`, etc. It is also able to coerce
symbolic expressions which inherit from :class:`~.Basic`. This can be
useful in cooperation with SAGE.
.. warning::
Note that this function uses ``eval``, and thus shouldn't be used on
unsanitized input.
If the argument is already a type that SymPy understands, it will do
nothing but return that value. This can be used at the beginning of a
function to ensure you are working with the correct type.
Examples
========
>>> from sympy import sympify
>>> sympify(2).is_integer
True
>>> sympify(2).is_real
True
>>> sympify(2.0).is_real
True
>>> sympify("2.0").is_real
True
>>> sympify("2e-45").is_real
True
If the expression could not be converted, a SympifyError is raised.
>>> sympify("x***2")
Traceback (most recent call last):
...
SympifyError: SympifyError: "could not parse 'x***2'"
When attempting to parse non-Python syntax using ``sympify``, it raises a
``SympifyError``:
>>> sympify("2x+1")
Traceback (most recent call last):
...
SympifyError: Sympify of expression 'could not parse '2x+1'' failed
To parse non-Python syntax, use ``parse_expr`` from ``sympy.parsing.sympy_parser``.
>>> from sympy.parsing.sympy_parser import parse_expr
>>> parse_expr("2x+1", transformations="all")
2*x + 1
For more details about ``transformations``: see :func:`~sympy.parsing.sympy_parser.parse_expr`
Locals
------
The sympification happens with access to everything that is loaded
by ``from sympy import *``; anything used in a string that is not
defined by that import will be converted to a symbol. In the following,
the ``bitcount`` function is treated as a symbol and the ``O`` is
interpreted as the :class:`~.Order` object (used with series) and it raises
an error when used improperly:
>>> s = 'bitcount(42)'
>>> sympify(s)
bitcount(42)
>>> sympify("O(x)")
O(x)
>>> sympify("O + 1")
Traceback (most recent call last):
...
TypeError: unbound method...
In order to have ``bitcount`` be recognized it can be imported into a
namespace dictionary and passed as locals:
>>> ns = {}
>>> exec('from sympy.core.evalf import bitcount', ns)
>>> sympify(s, locals=ns)
6
In order to have the ``O`` interpreted as a Symbol, identify it as such
in the namespace dictionary. This can be done in a variety of ways; all
three of the following are possibilities:
>>> from sympy import Symbol
>>> ns["O"] = Symbol("O") # method 1
>>> exec('from sympy.abc import O', ns) # method 2
>>> ns.update(dict(O=Symbol("O"))) # method 3
>>> sympify("O + 1", locals=ns)
O + 1
If you want *all* single-letter and Greek-letter variables to be symbols
then you can use the clashing-symbols dictionaries that have been defined
there as private variables: ``_clash1`` (single-letter variables),
``_clash2`` (the multi-letter Greek names) or ``_clash`` (both single and
multi-letter names that are defined in ``abc``).
>>> from sympy.abc import _clash1
>>> set(_clash1) # if this fails, see issue #23903
{'E', 'I', 'N', 'O', 'Q', 'S'}
>>> sympify('I & Q', _clash1)
I & Q
Strict
------
If the option ``strict`` is set to ``True``, only the types for which an
explicit conversion has been defined are converted. In the other
cases, a SympifyError is raised.
>>> print(sympify(None))
None
>>> sympify(None, strict=True)
Traceback (most recent call last):
...
SympifyError: SympifyError: None
.. deprecated:: 1.6
``sympify(obj)`` automatically falls back to ``str(obj)`` when all
other conversion methods fail, but this is deprecated. ``strict=True``
will disable this deprecated behavior. See
:ref:`deprecated-sympify-string-fallback`.
Evaluation
----------
If the option ``evaluate`` is set to ``False``, then arithmetic and
operators will be converted into their SymPy equivalents and the
``evaluate=False`` option will be added. Nested ``Add`` or ``Mul`` will
be denested first. This is done via an AST transformation that replaces
operators with their SymPy equivalents, so if an operand redefines any
of those operations, the redefined operators will not be used. If
argument a is not a string, the mathematical expression is evaluated
before being passed to sympify, so adding ``evaluate=False`` will still
return the evaluated result of expression.
>>> sympify('2**2 / 3 + 5')
19/3
>>> sympify('2**2 / 3 + 5', evaluate=False)
2**2/3 + 5
>>> sympify('4/2+7', evaluate=True)
9
>>> sympify('4/2+7', evaluate=False)
4/2 + 7
>>> sympify(4/2+7, evaluate=False)
9.00000000000000
Extending
---------
To extend ``sympify`` to convert custom objects (not derived from ``Basic``),
just define a ``_sympy_`` method to your class. You can do that even to
classes that you do not own by subclassing or adding the method at runtime.
>>> from sympy import Matrix
>>> class MyList1(object):
... def __iter__(self):
... yield 1
... yield 2
... return
... def __getitem__(self, i): return list(self)[i]
... def _sympy_(self): return Matrix(self)
>>> sympify(MyList1())
Matrix([
[1],
[2]])
If you do not have control over the class definition you could also use the
``converter`` global dictionary. The key is the class and the value is a
function that takes a single argument and returns the desired SymPy
object, e.g. ``converter[MyList] = lambda x: Matrix(x)``.
>>> class MyList2(object): # XXX Do not do this if you control the class!
... def __iter__(self): # Use _sympy_!
... yield 1
... yield 2
... return
... def __getitem__(self, i): return list(self)[i]
>>> from sympy.core.sympify import converter
>>> converter[MyList2] = lambda x: Matrix(x)
>>> sympify(MyList2())
Matrix([
[1],
[2]])
Notes
=====
The keywords ``rational`` and ``convert_xor`` are only used
when the input is a string.
convert_xor
-----------
>>> sympify('x^y',convert_xor=True)
x**y
>>> sympify('x^y',convert_xor=False)
x ^ y
rational
--------
>>> sympify('0.1',rational=False)
0.1
>>> sympify('0.1',rational=True)
1/10
Sometimes autosimplification during sympification results in expressions
that are very different in structure than what was entered. Until such
autosimplification is no longer done, the ``kernS`` function might be of
some use. In the example below you can see how an expression reduces to
$-1$ by autosimplification, but does not do so when ``kernS`` is used.
>>> from sympy.core.sympify import kernS
>>> from sympy.abc import x
>>> -2*(-(-x + 1/x)/(x*(x - 1/x)**2) - 1/(x*(x - 1/x))) - 1
-1
>>> s = '-2*(-(-x + 1/x)/(x*(x - 1/x)**2) - 1/(x*(x - 1/x))) - 1'
>>> sympify(s)
-1
>>> kernS(s)
-2*(-(-x + 1/x)/(x*(x - 1/x)**2) - 1/(x*(x - 1/x))) - 1
Parameters
==========
a :
- any object defined in SymPy
- standard numeric Python types: ``int``, ``long``, ``float``, ``Decimal``
- strings (like ``"0.09"``, ``"2e-19"`` or ``'sin(x)'``)
- booleans, including ``None`` (will leave ``None`` unchanged)
- dicts, lists, sets or tuples containing any of the above
convert_xor : bool, optional
If true, treats ``^`` as exponentiation.
If False, treats ``^`` as XOR itself.
Used only when input is a string.
locals : any object defined in SymPy, optional
In order to have strings be recognized it can be imported
into a namespace dictionary and passed as locals.
strict : bool, optional
If the option strict is set to ``True``, only the types for which
an explicit conversion has been defined are converted. In the
other cases, a SympifyError is raised.
rational : bool, optional
If ``True``, converts floats into :class:`~.Rational`.
If ``False``, it lets floats remain as it is.
Used only when input is a string.
evaluate : bool, optional
If False, then arithmetic and operators will be converted into
their SymPy equivalents. If True the expression will be evaluated
and the result will be returned.
"""
# XXX: If a is a Basic subclass rather than instance (e.g. sin rather than
# sin(x)) then a.__sympy__ will be the property. Only on the instance will
# a.__sympy__ give the *value* of the property (True). Since sympify(sin)
# was used for a long time we allow it to pass. However if strict=True as
# is the case in internal calls to _sympify then we only allow
# is_sympy=True.
#
# https://github.com/sympy/sympy/issues/20124
is_sympy = getattr(a, '__sympy__', None)
if is_sympy is True:
return a
elif is_sympy is not None:
if not strict:
return a
else:
raise SympifyError(a)
if isinstance(a, CantSympify):
raise SympifyError(a)
cls = getattr(a, "__class__", None)
#Check if there exists a converter for any of the types in the mro
for superclass in getmro(cls):
#First check for user defined converters
conv = _external_converter.get(superclass)
if conv is None:
#if none exists, check for SymPy defined converters
conv = _sympy_converter.get(superclass)
if conv is not None:
return conv(a)
if cls is type(None):
if strict:
raise SympifyError(a)
else:
return a
if evaluate is None:
evaluate = global_parameters.evaluate
# Support for basic numpy datatypes
if _is_numpy_instance(a):
import numpy as np
if np.isscalar(a):
return _convert_numpy_types(a, locals=locals,
convert_xor=convert_xor, strict=strict, rational=rational,
evaluate=evaluate)
_sympy_ = getattr(a, "_sympy_", None)
if _sympy_ is not None:
return a._sympy_()
if not strict:
# Put numpy array conversion _before_ float/int, see
# <https://github.com/sympy/sympy/issues/13924>.
flat = getattr(a, "flat", None)
if flat is not None:
shape = getattr(a, "shape", None)
if shape is not None:
from sympy.tensor.array import Array
return Array(a.flat, a.shape) # works with e.g. NumPy arrays
if not isinstance(a, str):
if _is_numpy_instance(a):
import numpy as np
assert not isinstance(a, np.number)
if isinstance(a, np.ndarray):
# Scalar arrays (those with zero dimensions) have sympify
# called on the scalar element.
if a.ndim == 0:
try:
return sympify(a.item(),
locals=locals,
convert_xor=convert_xor,
strict=strict,
rational=rational,
evaluate=evaluate)
except SympifyError:
pass
elif hasattr(a, '__float__'):
# float and int can coerce size-one numpy arrays to their lone
# element. See issue https://github.com/numpy/numpy/issues/10404.
return sympify(float(a))
elif hasattr(a, '__int__'):
return sympify(int(a))
if strict:
raise SympifyError(a)
if iterable(a):
try:
return type(a)([sympify(x, locals=locals, convert_xor=convert_xor,
rational=rational, evaluate=evaluate) for x in a])
except TypeError:
# Not all iterables are rebuildable with their type.
pass
if not isinstance(a, str):
raise SympifyError('cannot sympify object of type %r' % type(a))
from sympy.parsing.sympy_parser import (parse_expr, TokenError,
standard_transformations)
from sympy.parsing.sympy_parser import convert_xor as t_convert_xor
from sympy.parsing.sympy_parser import rationalize as t_rationalize
transformations = standard_transformations
if rational:
transformations += (t_rationalize,)
if convert_xor:
transformations += (t_convert_xor,)
try:
a = a.replace('\n', '')
expr = parse_expr(a, local_dict=locals, transformations=transformations, evaluate=evaluate)
except (TokenError, SyntaxError) as exc:
raise SympifyError('could not parse %r' % a, exc)
return expr
def _sympify(a):
"""
Short version of :func:`~.sympify` for internal usage for ``__add__`` and
``__eq__`` methods where it is ok to allow some things (like Python
integers and floats) in the expression. This excludes things (like strings)
that are unwise to allow into such an expression.
>>> from sympy import Integer
>>> Integer(1) == 1
True
>>> Integer(1) == '1'
False
>>> from sympy.abc import x
>>> x + 1
x + 1
>>> x + '1'
Traceback (most recent call last):
...
TypeError: unsupported operand type(s) for +: 'Symbol' and 'str'
see: sympify
"""
return sympify(a, strict=True)
def kernS(s):
"""Use a hack to try keep autosimplification from distributing a
a number into an Add; this modification does not
prevent the 2-arg Mul from becoming an Add, however.
Examples
========
>>> from sympy.core.sympify import kernS
>>> from sympy.abc import x, y
The 2-arg Mul distributes a number (or minus sign) across the terms
of an expression, but kernS will prevent that:
>>> 2*(x + y), -(x + 1)
(2*x + 2*y, -x - 1)
>>> kernS('2*(x + y)')
2*(x + y)
>>> kernS('-(x + 1)')
-(x + 1)
If use of the hack fails, the un-hacked string will be passed to sympify...
and you get what you get.
XXX This hack should not be necessary once issue 4596 has been resolved.
"""
hit = False
quoted = '"' in s or "'" in s
if '(' in s and not quoted:
if s.count('(') != s.count(")"):
raise SympifyError('unmatched left parenthesis')
# strip all space from s
s = ''.join(s.split())
olds = s
# now use space to represent a symbol that
# will
# step 1. turn potential 2-arg Muls into 3-arg versions
# 1a. *( -> * *(
s = s.replace('*(', '* *(')
# 1b. close up exponentials
s = s.replace('** *', '**')
# 2. handle the implied multiplication of a negated
# parenthesized expression in two steps
# 2a: -(...) --> -( *(...)
target = '-( *('
s = s.replace('-(', target)
# 2b: double the matching closing parenthesis
# -( *(...) --> -( *(...))
i = nest = 0
assert target.endswith('(') # assumption below
while True:
j = s.find(target, i)
if j == -1:
break
j += len(target) - 1
for j in range(j, len(s)):
if s[j] == "(":
nest += 1
elif s[j] == ")":
nest -= 1
if nest == 0:
break
s = s[:j] + ")" + s[j:]
i = j + 2 # the first char after 2nd )
if ' ' in s:
# get a unique kern
kern = '_'
while kern in s:
kern += choice(string.ascii_letters + string.digits)
s = s.replace(' ', kern)
hit = kern in s
else:
hit = False
for i in range(2):
try:
expr = sympify(s)
break
except TypeError: # the kern might cause unknown errors...
if hit:
s = olds # maybe it didn't like the kern; use un-kerned s
hit = False
continue
expr = sympify(s) # let original error raise
if not hit:
return expr
from .symbol import Symbol
rep = {Symbol(kern): 1}
def _clear(expr):
if isinstance(expr, (list, tuple, set)):
return type(expr)([_clear(e) for e in expr])
if hasattr(expr, 'subs'):
return expr.subs(rep, hack2=True)
return expr
expr = _clear(expr)
# hope that kern is not there anymore
return expr
# Avoid circular import
from .basic import Basic
PK ]ZZZ���\ \ sympy/core/trace.pyfrom sympy.utilities.exceptions import sympy_deprecation_warning
sympy_deprecation_warning(
"""
sympy.core.trace is deprecated. Use sympy.physics.quantum.trace
instead.
""",
deprecated_since_version="1.10",
active_deprecations_target="sympy-core-trace-deprecated",
)
from sympy.physics.quantum.trace import Tr # noqa:F401
PK ]ZZZ$��H" H" sympy/core/traversal.pyfrom .basic import Basic
from .sorting import ordered
from .sympify import sympify
from sympy.utilities.iterables import iterable
def iterargs(expr):
"""Yield the args of a Basic object in a breadth-first traversal.
Depth-traversal stops if `arg.args` is either empty or is not
an iterable.
Examples
========
>>> from sympy import Integral, Function
>>> from sympy.abc import x
>>> f = Function('f')
>>> from sympy.core.traversal import iterargs
>>> list(iterargs(Integral(f(x), (f(x), 1))))
[Integral(f(x), (f(x), 1)), f(x), (f(x), 1), x, f(x), 1, x]
See Also
========
iterfreeargs, preorder_traversal
"""
args = [expr]
for i in args:
yield i
args.extend(i.args)
def iterfreeargs(expr, _first=True):
"""Yield the args of a Basic object in a breadth-first traversal.
Depth-traversal stops if `arg.args` is either empty or is not
an iterable. The bound objects of an expression will be returned
as canonical variables.
Examples
========
>>> from sympy import Integral, Function
>>> from sympy.abc import x
>>> f = Function('f')
>>> from sympy.core.traversal import iterfreeargs
>>> list(iterfreeargs(Integral(f(x), (f(x), 1))))
[Integral(f(x), (f(x), 1)), 1]
See Also
========
iterargs, preorder_traversal
"""
args = [expr]
for i in args:
yield i
if _first and hasattr(i, 'bound_symbols'):
void = i.canonical_variables.values()
for i in iterfreeargs(i.as_dummy(), _first=False):
if not i.has(*void):
yield i
args.extend(i.args)
class preorder_traversal:
"""
Do a pre-order traversal of a tree.
This iterator recursively yields nodes that it has visited in a pre-order
fashion. That is, it yields the current node then descends through the
tree breadth-first to yield all of a node's children's pre-order
traversal.
For an expression, the order of the traversal depends on the order of
.args, which in many cases can be arbitrary.
Parameters
==========
node : SymPy expression
The expression to traverse.
keys : (default None) sort key(s)
The key(s) used to sort args of Basic objects. When None, args of Basic
objects are processed in arbitrary order. If key is defined, it will
be passed along to ordered() as the only key(s) to use to sort the
arguments; if ``key`` is simply True then the default keys of ordered
will be used.
Yields
======
subtree : SymPy expression
All of the subtrees in the tree.
Examples
========
>>> from sympy import preorder_traversal, symbols
>>> x, y, z = symbols('x y z')
The nodes are returned in the order that they are encountered unless key
is given; simply passing key=True will guarantee that the traversal is
unique.
>>> list(preorder_traversal((x + y)*z, keys=None)) # doctest: +SKIP
[z*(x + y), z, x + y, y, x]
>>> list(preorder_traversal((x + y)*z, keys=True))
[z*(x + y), z, x + y, x, y]
"""
def __init__(self, node, keys=None):
self._skip_flag = False
self._pt = self._preorder_traversal(node, keys)
def _preorder_traversal(self, node, keys):
yield node
if self._skip_flag:
self._skip_flag = False
return
if isinstance(node, Basic):
if not keys and hasattr(node, '_argset'):
# LatticeOp keeps args as a set. We should use this if we
# don't care about the order, to prevent unnecessary sorting.
args = node._argset
else:
args = node.args
if keys:
if keys != True:
args = ordered(args, keys, default=False)
else:
args = ordered(args)
for arg in args:
yield from self._preorder_traversal(arg, keys)
elif iterable(node):
for item in node:
yield from self._preorder_traversal(item, keys)
def skip(self):
"""
Skip yielding current node's (last yielded node's) subtrees.
Examples
========
>>> from sympy import preorder_traversal, symbols
>>> x, y, z = symbols('x y z')
>>> pt = preorder_traversal((x + y*z)*z)
>>> for i in pt:
... print(i)
... if i == x + y*z:
... pt.skip()
z*(x + y*z)
z
x + y*z
"""
self._skip_flag = True
def __next__(self):
return next(self._pt)
def __iter__(self):
return self
def use(expr, func, level=0, args=(), kwargs={}):
"""
Use ``func`` to transform ``expr`` at the given level.
Examples
========
>>> from sympy import use, expand
>>> from sympy.abc import x, y
>>> f = (x + y)**2*x + 1
>>> use(f, expand, level=2)
x*(x**2 + 2*x*y + y**2) + 1
>>> expand(f)
x**3 + 2*x**2*y + x*y**2 + 1
"""
def _use(expr, level):
if not level:
return func(expr, *args, **kwargs)
else:
if expr.is_Atom:
return expr
else:
level -= 1
_args = [_use(arg, level) for arg in expr.args]
return expr.__class__(*_args)
return _use(sympify(expr), level)
def walk(e, *target):
"""Iterate through the args that are the given types (target) and
return a list of the args that were traversed; arguments
that are not of the specified types are not traversed.
Examples
========
>>> from sympy.core.traversal import walk
>>> from sympy import Min, Max
>>> from sympy.abc import x, y, z
>>> list(walk(Min(x, Max(y, Min(1, z))), Min))
[Min(x, Max(y, Min(1, z)))]
>>> list(walk(Min(x, Max(y, Min(1, z))), Min, Max))
[Min(x, Max(y, Min(1, z))), Max(y, Min(1, z)), Min(1, z)]
See Also
========
bottom_up
"""
if isinstance(e, target):
yield e
for i in e.args:
yield from walk(i, *target)
def bottom_up(rv, F, atoms=False, nonbasic=False):
"""Apply ``F`` to all expressions in an expression tree from the
bottom up. If ``atoms`` is True, apply ``F`` even if there are no args;
if ``nonbasic`` is True, try to apply ``F`` to non-Basic objects.
"""
args = getattr(rv, 'args', None)
if args is not None:
if args:
args = tuple([bottom_up(a, F, atoms, nonbasic) for a in args])
if args != rv.args:
rv = rv.func(*args)
rv = F(rv)
elif atoms:
rv = F(rv)
else:
if nonbasic:
try:
rv = F(rv)
except TypeError:
pass
return rv
def postorder_traversal(node, keys=None):
"""
Do a postorder traversal of a tree.
This generator recursively yields nodes that it has visited in a postorder
fashion. That is, it descends through the tree depth-first to yield all of
a node's children's postorder traversal before yielding the node itself.
Parameters
==========
node : SymPy expression
The expression to traverse.
keys : (default None) sort key(s)
The key(s) used to sort args of Basic objects. When None, args of Basic
objects are processed in arbitrary order. If key is defined, it will
be passed along to ordered() as the only key(s) to use to sort the
arguments; if ``key`` is simply True then the default keys of
``ordered`` will be used (node count and default_sort_key).
Yields
======
subtree : SymPy expression
All of the subtrees in the tree.
Examples
========
>>> from sympy import postorder_traversal
>>> from sympy.abc import w, x, y, z
The nodes are returned in the order that they are encountered unless key
is given; simply passing key=True will guarantee that the traversal is
unique.
>>> list(postorder_traversal(w + (x + y)*z)) # doctest: +SKIP
[z, y, x, x + y, z*(x + y), w, w + z*(x + y)]
>>> list(postorder_traversal(w + (x + y)*z, keys=True))
[w, z, x, y, x + y, z*(x + y), w + z*(x + y)]
"""
if isinstance(node, Basic):
args = node.args
if keys:
if keys != True:
args = ordered(args, keys, default=False)
else:
args = ordered(args)
for arg in args:
yield from postorder_traversal(arg, keys)
elif iterable(node):
for item in node:
yield from postorder_traversal(item, keys)
yield node
PK ]ZZZ ! sympy/core/benchmarks/__init__.pyPK ]ZZZ�"��� � # sympy/core/benchmarks/bench_arit.pyfrom sympy.core import Add, Mul, symbols
x, y, z = symbols('x,y,z')
def timeit_neg():
-x
def timeit_Add_x1():
x + 1
def timeit_Add_1x():
1 + x
def timeit_Add_x05():
x + 0.5
def timeit_Add_xy():
x + y
def timeit_Add_xyz():
Add(*[x, y, z])
def timeit_Mul_xy():
x*y
def timeit_Mul_xyz():
Mul(*[x, y, z])
def timeit_Div_xy():
x/y
def timeit_Div_2y():
2/y
PK ]ZZZ���_� � * sympy/core/benchmarks/bench_assumptions.pyfrom sympy.core import Symbol, Integer
x = Symbol('x')
i3 = Integer(3)
def timeit_x_is_integer():
x.is_integer
def timeit_Integer_is_irrational():
i3.is_irrational
PK ]ZZZg�l� � $ sympy/core/benchmarks/bench_basic.pyfrom sympy.core import symbols, S
x, y = symbols('x,y')
def timeit_Symbol_meth_lookup():
x.diff # no call, just method lookup
def timeit_S_lookup():
S.Exp1
def timeit_Symbol_eq_xy():
x == y
PK ]ZZZb��7� � % sympy/core/benchmarks/bench_expand.pyfrom sympy.core import symbols, I
x, y, z = symbols('x,y,z')
p = 3*x**2*y*z**7 + 7*x*y*z**2 + 4*x + x*y**4
e = (x + y + z + 1)**32
def timeit_expand_nothing_todo():
p.expand()
def bench_expand_32():
"""(x+y+z+1)**32 -> expand"""
e.expand()
def timeit_expand_complex_number_1():
((2 + 3*I)**1000).expand(complex=True)
def timeit_expand_complex_number_2():
((2 + 3*I/4)**1000).expand(complex=True)
PK ]ZZZO4"�o o & sympy/core/benchmarks/bench_numbers.pyfrom sympy.core.numbers import Integer, Rational, pi, oo
from sympy.core.intfunc import integer_nthroot, igcd
from sympy.core.singleton import S
i3 = Integer(3)
i4 = Integer(4)
r34 = Rational(3, 4)
q45 = Rational(4, 5)
def timeit_Integer_create():
Integer(2)
def timeit_Integer_int():
int(i3)
def timeit_neg_one():
-S.One
def timeit_Integer_neg():
-i3
def timeit_Integer_abs():
abs(i3)
def timeit_Integer_sub():
i3 - i3
def timeit_abs_pi():
abs(pi)
def timeit_neg_oo():
-oo
def timeit_Integer_add_i1():
i3 + 1
def timeit_Integer_add_ij():
i3 + i4
def timeit_Integer_add_Rational():
i3 + r34
def timeit_Integer_mul_i4():
i3*4
def timeit_Integer_mul_ij():
i3*i4
def timeit_Integer_mul_Rational():
i3*r34
def timeit_Integer_eq_i3():
i3 == 3
def timeit_Integer_ed_Rational():
i3 == r34
def timeit_integer_nthroot():
integer_nthroot(100, 2)
def timeit_number_igcd_23_17():
igcd(23, 17)
def timeit_number_igcd_60_3600():
igcd(60, 3600)
def timeit_Rational_add_r1():
r34 + 1
def timeit_Rational_add_rq():
r34 + q45
PK ]ZZZ�fA�� � & sympy/core/benchmarks/bench_sympify.pyfrom sympy.core import sympify, Symbol
x = Symbol('x')
def timeit_sympify_1():
sympify(1)
def timeit_sympify_x():
sympify(x)
PK ]ZZZy��n n sympy/crypto/__init__.pyfrom sympy.crypto.crypto import (cycle_list,
encipher_shift, encipher_affine, encipher_substitution,
check_and_join, encipher_vigenere, decipher_vigenere, bifid5_square,
bifid6_square, encipher_hill, decipher_hill,
encipher_bifid5, encipher_bifid6, decipher_bifid5,
decipher_bifid6, encipher_kid_rsa, decipher_kid_rsa,
kid_rsa_private_key, kid_rsa_public_key, decipher_rsa, rsa_private_key,
rsa_public_key, encipher_rsa, lfsr_connection_polynomial,
lfsr_autocorrelation, lfsr_sequence, encode_morse, decode_morse,
elgamal_private_key, elgamal_public_key, decipher_elgamal,
encipher_elgamal, dh_private_key, dh_public_key, dh_shared_key,
padded_key, encipher_bifid, decipher_bifid, bifid_square, bifid5,
bifid6, bifid10, decipher_gm, encipher_gm, gm_public_key,
gm_private_key, bg_private_key, bg_public_key, encipher_bg, decipher_bg,
encipher_rot13, decipher_rot13, encipher_atbash, decipher_atbash,
encipher_railfence, decipher_railfence)
__all__ = [
'cycle_list', 'encipher_shift', 'encipher_affine',
'encipher_substitution', 'check_and_join', 'encipher_vigenere',
'decipher_vigenere', 'bifid5_square', 'bifid6_square', 'encipher_hill',
'decipher_hill', 'encipher_bifid5', 'encipher_bifid6', 'decipher_bifid5',
'decipher_bifid6', 'encipher_kid_rsa', 'decipher_kid_rsa',
'kid_rsa_private_key', 'kid_rsa_public_key', 'decipher_rsa',
'rsa_private_key', 'rsa_public_key', 'encipher_rsa',
'lfsr_connection_polynomial', 'lfsr_autocorrelation', 'lfsr_sequence',
'encode_morse', 'decode_morse', 'elgamal_private_key',
'elgamal_public_key', 'decipher_elgamal', 'encipher_elgamal',
'dh_private_key', 'dh_public_key', 'dh_shared_key', 'padded_key',
'encipher_bifid', 'decipher_bifid', 'bifid_square', 'bifid5', 'bifid6',
'bifid10', 'decipher_gm', 'encipher_gm', 'gm_public_key',
'gm_private_key', 'bg_private_key', 'bg_public_key', 'encipher_bg',
'decipher_bg', 'encipher_rot13', 'decipher_rot13', 'encipher_atbash',
'decipher_atbash', 'encipher_railfence', 'decipher_railfence',
]
PK ]ZZZ���C^ C^ sympy/crypto/crypto.py"""
This file contains some classical ciphers and routines
implementing a linear-feedback shift register (LFSR)
and the Diffie-Hellman key exchange.
.. warning::
This module is intended for educational purposes only. Do not use the
functions in this module for real cryptographic applications. If you wish
to encrypt real data, we recommend using something like the `cryptography
<https://cryptography.io/en/latest/>`_ module.
"""
from string import whitespace, ascii_uppercase as uppercase, printable
from functools import reduce
import warnings
from itertools import cycle
from sympy.external.gmpy import GROUND_TYPES
from sympy.core import Symbol
from sympy.core.numbers import Rational
from sympy.core.random import _randrange, _randint
from sympy.external.gmpy import gcd, invert
from sympy.functions.combinatorial.numbers import (totient as _euler,
reduced_totient as _carmichael)
from sympy.matrices import Matrix
from sympy.ntheory import isprime, primitive_root, factorint
from sympy.ntheory.generate import nextprime
from sympy.ntheory.modular import crt
from sympy.polys.domains import FF
from sympy.polys.polytools import Poly
from sympy.utilities.misc import as_int, filldedent, translate
from sympy.utilities.iterables import uniq, multiset
from sympy.utilities.decorator import doctest_depends_on
if GROUND_TYPES == 'flint':
__doctest_skip__ = ['lfsr_sequence']
class NonInvertibleCipherWarning(RuntimeWarning):
"""A warning raised if the cipher is not invertible."""
def __init__(self, msg):
self.fullMessage = msg
def __str__(self):
return '\n\t' + self.fullMessage
def warn(self, stacklevel=3):
warnings.warn(self, stacklevel=stacklevel)
def AZ(s=None):
"""Return the letters of ``s`` in uppercase. In case more than
one string is passed, each of them will be processed and a list
of upper case strings will be returned.
Examples
========
>>> from sympy.crypto.crypto import AZ
>>> AZ('Hello, world!')
'HELLOWORLD'
>>> AZ('Hello, world!'.split())
['HELLO', 'WORLD']
See Also
========
check_and_join
"""
if not s:
return uppercase
t = isinstance(s, str)
if t:
s = [s]
rv = [check_and_join(i.upper().split(), uppercase, filter=True)
for i in s]
if t:
return rv[0]
return rv
bifid5 = AZ().replace('J', '')
bifid6 = AZ() + '0123456789'
bifid10 = printable
def padded_key(key, symbols):
"""Return a string of the distinct characters of ``symbols`` with
those of ``key`` appearing first. A ValueError is raised if
a) there are duplicate characters in ``symbols`` or
b) there are characters in ``key`` that are not in ``symbols``.
Examples
========
>>> from sympy.crypto.crypto import padded_key
>>> padded_key('PUPPY', 'OPQRSTUVWXY')
'PUYOQRSTVWX'
>>> padded_key('RSA', 'ARTIST')
Traceback (most recent call last):
...
ValueError: duplicate characters in symbols: T
"""
syms = list(uniq(symbols))
if len(syms) != len(symbols):
extra = ''.join(sorted({
i for i in symbols if symbols.count(i) > 1}))
raise ValueError('duplicate characters in symbols: %s' % extra)
extra = set(key) - set(syms)
if extra:
raise ValueError(
'characters in key but not symbols: %s' % ''.join(
sorted(extra)))
key0 = ''.join(list(uniq(key)))
# remove from syms characters in key0
return key0 + translate(''.join(syms), None, key0)
def check_and_join(phrase, symbols=None, filter=None):
"""
Joins characters of ``phrase`` and if ``symbols`` is given, raises
an error if any character in ``phrase`` is not in ``symbols``.
Parameters
==========
phrase
String or list of strings to be returned as a string.
symbols
Iterable of characters allowed in ``phrase``.
If ``symbols`` is ``None``, no checking is performed.
Examples
========
>>> from sympy.crypto.crypto import check_and_join
>>> check_and_join('a phrase')
'a phrase'
>>> check_and_join('a phrase'.upper().split())
'APHRASE'
>>> check_and_join('a phrase!'.upper().split(), 'ARE', filter=True)
'ARAE'
>>> check_and_join('a phrase!'.upper().split(), 'ARE')
Traceback (most recent call last):
...
ValueError: characters in phrase but not symbols: "!HPS"
"""
rv = ''.join(''.join(phrase))
if symbols is not None:
symbols = check_and_join(symbols)
missing = ''.join(sorted(set(rv) - set(symbols)))
if missing:
if not filter:
raise ValueError(
'characters in phrase but not symbols: "%s"' % missing)
rv = translate(rv, None, missing)
return rv
def _prep(msg, key, alp, default=None):
if not alp:
if not default:
alp = AZ()
msg = AZ(msg)
key = AZ(key)
else:
alp = default
else:
alp = ''.join(alp)
key = check_and_join(key, alp, filter=True)
msg = check_and_join(msg, alp, filter=True)
return msg, key, alp
def cycle_list(k, n):
"""
Returns the elements of the list ``range(n)`` shifted to the
left by ``k`` (so the list starts with ``k`` (mod ``n``)).
Examples
========
>>> from sympy.crypto.crypto import cycle_list
>>> cycle_list(3, 10)
[3, 4, 5, 6, 7, 8, 9, 0, 1, 2]
"""
k = k % n
return list(range(k, n)) + list(range(k))
######## shift cipher examples ############
def encipher_shift(msg, key, symbols=None):
"""
Performs shift cipher encryption on plaintext msg, and returns the
ciphertext.
Parameters
==========
key : int
The secret key.
msg : str
Plaintext of upper-case letters.
Returns
=======
str
Ciphertext of upper-case letters.
Examples
========
>>> from sympy.crypto.crypto import encipher_shift, decipher_shift
>>> msg = "GONAVYBEATARMY"
>>> ct = encipher_shift(msg, 1); ct
'HPOBWZCFBUBSNZ'
To decipher the shifted text, change the sign of the key:
>>> encipher_shift(ct, -1)
'GONAVYBEATARMY'
There is also a convenience function that does this with the
original key:
>>> decipher_shift(ct, 1)
'GONAVYBEATARMY'
Notes
=====
ALGORITHM:
STEPS:
0. Number the letters of the alphabet from 0, ..., N
1. Compute from the string ``msg`` a list ``L1`` of
corresponding integers.
2. Compute from the list ``L1`` a new list ``L2``, given by
adding ``(k mod 26)`` to each element in ``L1``.
3. Compute from the list ``L2`` a string ``ct`` of
corresponding letters.
The shift cipher is also called the Caesar cipher, after
Julius Caesar, who, according to Suetonius, used it with a
shift of three to protect messages of military significance.
Caesar's nephew Augustus reportedly used a similar cipher, but
with a right shift of 1.
References
==========
.. [1] https://en.wikipedia.org/wiki/Caesar_cipher
.. [2] https://mathworld.wolfram.com/CaesarsMethod.html
See Also
========
decipher_shift
"""
msg, _, A = _prep(msg, '', symbols)
shift = len(A) - key % len(A)
key = A[shift:] + A[:shift]
return translate(msg, key, A)
def decipher_shift(msg, key, symbols=None):
"""
Return the text by shifting the characters of ``msg`` to the
left by the amount given by ``key``.
Examples
========
>>> from sympy.crypto.crypto import encipher_shift, decipher_shift
>>> msg = "GONAVYBEATARMY"
>>> ct = encipher_shift(msg, 1); ct
'HPOBWZCFBUBSNZ'
To decipher the shifted text, change the sign of the key:
>>> encipher_shift(ct, -1)
'GONAVYBEATARMY'
Or use this function with the original key:
>>> decipher_shift(ct, 1)
'GONAVYBEATARMY'
"""
return encipher_shift(msg, -key, symbols)
def encipher_rot13(msg, symbols=None):
"""
Performs the ROT13 encryption on a given plaintext ``msg``.
Explanation
===========
ROT13 is a substitution cipher which substitutes each letter
in the plaintext message for the letter furthest away from it
in the English alphabet.
Equivalently, it is just a Caeser (shift) cipher with a shift
key of 13 (midway point of the alphabet).
References
==========
.. [1] https://en.wikipedia.org/wiki/ROT13
See Also
========
decipher_rot13
encipher_shift
"""
return encipher_shift(msg, 13, symbols)
def decipher_rot13(msg, symbols=None):
"""
Performs the ROT13 decryption on a given plaintext ``msg``.
Explanation
============
``decipher_rot13`` is equivalent to ``encipher_rot13`` as both
``decipher_shift`` with a key of 13 and ``encipher_shift`` key with a
key of 13 will return the same results. Nonetheless,
``decipher_rot13`` has nonetheless been explicitly defined here for
consistency.
Examples
========
>>> from sympy.crypto.crypto import encipher_rot13, decipher_rot13
>>> msg = 'GONAVYBEATARMY'
>>> ciphertext = encipher_rot13(msg);ciphertext
'TBANILORNGNEZL'
>>> decipher_rot13(ciphertext)
'GONAVYBEATARMY'
>>> encipher_rot13(msg) == decipher_rot13(msg)
True
>>> msg == decipher_rot13(ciphertext)
True
"""
return decipher_shift(msg, 13, symbols)
######## affine cipher examples ############
def encipher_affine(msg, key, symbols=None, _inverse=False):
r"""
Performs the affine cipher encryption on plaintext ``msg``, and
returns the ciphertext.
Explanation
===========
Encryption is based on the map `x \rightarrow ax+b` (mod `N`)
where ``N`` is the number of characters in the alphabet.
Decryption is based on the map `x \rightarrow cx+d` (mod `N`),
where `c = a^{-1}` (mod `N`) and `d = -a^{-1}b` (mod `N`).
In particular, for the map to be invertible, we need
`\mathrm{gcd}(a, N) = 1` and an error will be raised if this is
not true.
Parameters
==========
msg : str
Characters that appear in ``symbols``.
a, b : int, int
A pair integers, with ``gcd(a, N) = 1`` (the secret key).
symbols
String of characters (default = uppercase letters).
When no symbols are given, ``msg`` is converted to upper case
letters and all other characters are ignored.
Returns
=======
ct
String of characters (the ciphertext message)
Notes
=====
ALGORITHM:
STEPS:
0. Number the letters of the alphabet from 0, ..., N
1. Compute from the string ``msg`` a list ``L1`` of
corresponding integers.
2. Compute from the list ``L1`` a new list ``L2``, given by
replacing ``x`` by ``a*x + b (mod N)``, for each element
``x`` in ``L1``.
3. Compute from the list ``L2`` a string ``ct`` of
corresponding letters.
This is a straightforward generalization of the shift cipher with
the added complexity of requiring 2 characters to be deciphered in
order to recover the key.
References
==========
.. [1] https://en.wikipedia.org/wiki/Affine_cipher
See Also
========
decipher_affine
"""
msg, _, A = _prep(msg, '', symbols)
N = len(A)
a, b = key
assert gcd(a, N) == 1
if _inverse:
c = invert(a, N)
d = -b*c
a, b = c, d
B = ''.join([A[(a*i + b) % N] for i in range(N)])
return translate(msg, A, B)
def decipher_affine(msg, key, symbols=None):
r"""
Return the deciphered text that was made from the mapping,
`x \rightarrow ax+b` (mod `N`), where ``N`` is the
number of characters in the alphabet. Deciphering is done by
reciphering with a new key: `x \rightarrow cx+d` (mod `N`),
where `c = a^{-1}` (mod `N`) and `d = -a^{-1}b` (mod `N`).
Examples
========
>>> from sympy.crypto.crypto import encipher_affine, decipher_affine
>>> msg = "GO NAVY BEAT ARMY"
>>> key = (3, 1)
>>> encipher_affine(msg, key)
'TROBMVENBGBALV'
>>> decipher_affine(_, key)
'GONAVYBEATARMY'
See Also
========
encipher_affine
"""
return encipher_affine(msg, key, symbols, _inverse=True)
def encipher_atbash(msg, symbols=None):
r"""
Enciphers a given ``msg`` into its Atbash ciphertext and returns it.
Explanation
===========
Atbash is a substitution cipher originally used to encrypt the Hebrew
alphabet. Atbash works on the principle of mapping each alphabet to its
reverse / counterpart (i.e. a would map to z, b to y etc.)
Atbash is functionally equivalent to the affine cipher with ``a = 25``
and ``b = 25``
See Also
========
decipher_atbash
"""
return encipher_affine(msg, (25, 25), symbols)
def decipher_atbash(msg, symbols=None):
r"""
Deciphers a given ``msg`` using Atbash cipher and returns it.
Explanation
===========
``decipher_atbash`` is functionally equivalent to ``encipher_atbash``.
However, it has still been added as a separate function to maintain
consistency.
Examples
========
>>> from sympy.crypto.crypto import encipher_atbash, decipher_atbash
>>> msg = 'GONAVYBEATARMY'
>>> encipher_atbash(msg)
'TLMZEBYVZGZINB'
>>> decipher_atbash(msg)
'TLMZEBYVZGZINB'
>>> encipher_atbash(msg) == decipher_atbash(msg)
True
>>> msg == encipher_atbash(encipher_atbash(msg))
True
References
==========
.. [1] https://en.wikipedia.org/wiki/Atbash
See Also
========
encipher_atbash
"""
return decipher_affine(msg, (25, 25), symbols)
#################### substitution cipher ###########################
def encipher_substitution(msg, old, new=None):
r"""
Returns the ciphertext obtained by replacing each character that
appears in ``old`` with the corresponding character in ``new``.
If ``old`` is a mapping, then new is ignored and the replacements
defined by ``old`` are used.
Explanation
===========
This is a more general than the affine cipher in that the key can
only be recovered by determining the mapping for each symbol.
Though in practice, once a few symbols are recognized the mappings
for other characters can be quickly guessed.
Examples
========
>>> from sympy.crypto.crypto import encipher_substitution, AZ
>>> old = 'OEYAG'
>>> new = '034^6'
>>> msg = AZ("go navy! beat army!")
>>> ct = encipher_substitution(msg, old, new); ct
'60N^V4B3^T^RM4'
To decrypt a substitution, reverse the last two arguments:
>>> encipher_substitution(ct, new, old)
'GONAVYBEATARMY'
In the special case where ``old`` and ``new`` are a permutation of
order 2 (representing a transposition of characters) their order
is immaterial:
>>> old = 'NAVY'
>>> new = 'ANYV'
>>> encipher = lambda x: encipher_substitution(x, old, new)
>>> encipher('NAVY')
'ANYV'
>>> encipher(_)
'NAVY'
The substitution cipher, in general, is a method
whereby "units" (not necessarily single characters) of plaintext
are replaced with ciphertext according to a regular system.
>>> ords = dict(zip('abc', ['\\%i' % ord(i) for i in 'abc']))
>>> print(encipher_substitution('abc', ords))
\97\98\99
References
==========
.. [1] https://en.wikipedia.org/wiki/Substitution_cipher
"""
return translate(msg, old, new)
######################################################################
#################### Vigenere cipher examples ########################
######################################################################
def encipher_vigenere(msg, key, symbols=None):
"""
Performs the Vigenere cipher encryption on plaintext ``msg``, and
returns the ciphertext.
Examples
========
>>> from sympy.crypto.crypto import encipher_vigenere, AZ
>>> key = "encrypt"
>>> msg = "meet me on monday"
>>> encipher_vigenere(msg, key)
'QRGKKTHRZQEBPR'
Section 1 of the Kryptos sculpture at the CIA headquarters
uses this cipher and also changes the order of the
alphabet [2]_. Here is the first line of that section of
the sculpture:
>>> from sympy.crypto.crypto import decipher_vigenere, padded_key
>>> alp = padded_key('KRYPTOS', AZ())
>>> key = 'PALIMPSEST'
>>> msg = 'EMUFPHZLRFAXYUSDJKZLDKRNSHGNFIVJ'
>>> decipher_vigenere(msg, key, alp)
'BETWEENSUBTLESHADINGANDTHEABSENC'
Explanation
===========
The Vigenere cipher is named after Blaise de Vigenere, a sixteenth
century diplomat and cryptographer, by a historical accident.
Vigenere actually invented a different and more complicated cipher.
The so-called *Vigenere cipher* was actually invented
by Giovan Batista Belaso in 1553.
This cipher was used in the 1800's, for example, during the American
Civil War. The Confederacy used a brass cipher disk to implement the
Vigenere cipher (now on display in the NSA Museum in Fort
Meade) [1]_.
The Vigenere cipher is a generalization of the shift cipher.
Whereas the shift cipher shifts each letter by the same amount
(that amount being the key of the shift cipher) the Vigenere
cipher shifts a letter by an amount determined by the key (which is
a word or phrase known only to the sender and receiver).
For example, if the key was a single letter, such as "C", then the
so-called Vigenere cipher is actually a shift cipher with a
shift of `2` (since "C" is the 2nd letter of the alphabet, if
you start counting at `0`). If the key was a word with two
letters, such as "CA", then the so-called Vigenere cipher will
shift letters in even positions by `2` and letters in odd positions
are left alone (shifted by `0`, since "A" is the 0th letter, if
you start counting at `0`).
ALGORITHM:
INPUT:
``msg``: string of characters that appear in ``symbols``
(the plaintext)
``key``: a string of characters that appear in ``symbols``
(the secret key)
``symbols``: a string of letters defining the alphabet
OUTPUT:
``ct``: string of characters (the ciphertext message)
STEPS:
0. Number the letters of the alphabet from 0, ..., N
1. Compute from the string ``key`` a list ``L1`` of
corresponding integers. Let ``n1 = len(L1)``.
2. Compute from the string ``msg`` a list ``L2`` of
corresponding integers. Let ``n2 = len(L2)``.
3. Break ``L2`` up sequentially into sublists of size
``n1``; the last sublist may be smaller than ``n1``
4. For each of these sublists ``L`` of ``L2``, compute a
new list ``C`` given by ``C[i] = L[i] + L1[i] (mod N)``
to the ``i``-th element in the sublist, for each ``i``.
5. Assemble these lists ``C`` by concatenation into a new
list of length ``n2``.
6. Compute from the new list a string ``ct`` of
corresponding letters.
Once it is known that the key is, say, `n` characters long,
frequency analysis can be applied to every `n`-th letter of
the ciphertext to determine the plaintext. This method is
called *Kasiski examination* (although it was first discovered
by Babbage). If they key is as long as the message and is
comprised of randomly selected characters -- a one-time pad -- the
message is theoretically unbreakable.
The cipher Vigenere actually discovered is an "auto-key" cipher
described as follows.
ALGORITHM:
INPUT:
``key``: a string of letters (the secret key)
``msg``: string of letters (the plaintext message)
OUTPUT:
``ct``: string of upper-case letters (the ciphertext message)
STEPS:
0. Number the letters of the alphabet from 0, ..., N
1. Compute from the string ``msg`` a list ``L2`` of
corresponding integers. Let ``n2 = len(L2)``.
2. Let ``n1`` be the length of the key. Append to the
string ``key`` the first ``n2 - n1`` characters of
the plaintext message. Compute from this string (also of
length ``n2``) a list ``L1`` of integers corresponding
to the letter numbers in the first step.
3. Compute a new list ``C`` given by
``C[i] = L1[i] + L2[i] (mod N)``.
4. Compute from the new list a string ``ct`` of letters
corresponding to the new integers.
To decipher the auto-key ciphertext, the key is used to decipher
the first ``n1`` characters and then those characters become the
key to decipher the next ``n1`` characters, etc...:
>>> m = AZ('go navy, beat army! yes you can'); m
'GONAVYBEATARMYYESYOUCAN'
>>> key = AZ('gold bug'); n1 = len(key); n2 = len(m)
>>> auto_key = key + m[:n2 - n1]; auto_key
'GOLDBUGGONAVYBEATARMYYE'
>>> ct = encipher_vigenere(m, auto_key); ct
'MCYDWSHKOGAMKZCELYFGAYR'
>>> n1 = len(key)
>>> pt = []
>>> while ct:
... part, ct = ct[:n1], ct[n1:]
... pt.append(decipher_vigenere(part, key))
... key = pt[-1]
...
>>> ''.join(pt) == m
True
References
==========
.. [1] https://en.wikipedia.org/wiki/Vigenere_cipher
.. [2] https://web.archive.org/web/20071116100808/https://filebox.vt.edu/users/batman/kryptos.html
(short URL: https://goo.gl/ijr22d)
"""
msg, key, A = _prep(msg, key, symbols)
map = {c: i for i, c in enumerate(A)}
key = [map[c] for c in key]
N = len(map)
k = len(key)
rv = []
for i, m in enumerate(msg):
rv.append(A[(map[m] + key[i % k]) % N])
rv = ''.join(rv)
return rv
def decipher_vigenere(msg, key, symbols=None):
"""
Decode using the Vigenere cipher.
Examples
========
>>> from sympy.crypto.crypto import decipher_vigenere
>>> key = "encrypt"
>>> ct = "QRGK kt HRZQE BPR"
>>> decipher_vigenere(ct, key)
'MEETMEONMONDAY'
"""
msg, key, A = _prep(msg, key, symbols)
map = {c: i for i, c in enumerate(A)}
N = len(A) # normally, 26
K = [map[c] for c in key]
n = len(K)
C = [map[c] for c in msg]
rv = ''.join([A[(-K[i % n] + c) % N] for i, c in enumerate(C)])
return rv
#################### Hill cipher ########################
def encipher_hill(msg, key, symbols=None, pad="Q"):
r"""
Return the Hill cipher encryption of ``msg``.
Explanation
===========
The Hill cipher [1]_, invented by Lester S. Hill in the 1920's [2]_,
was the first polygraphic cipher in which it was practical
(though barely) to operate on more than three symbols at once.
The following discussion assumes an elementary knowledge of
matrices.
First, each letter is first encoded as a number starting with 0.
Suppose your message `msg` consists of `n` capital letters, with no
spaces. This may be regarded an `n`-tuple M of elements of
`Z_{26}` (if the letters are those of the English alphabet). A key
in the Hill cipher is a `k x k` matrix `K`, all of whose entries
are in `Z_{26}`, such that the matrix `K` is invertible (i.e., the
linear transformation `K: Z_{N}^k \rightarrow Z_{N}^k`
is one-to-one).
Parameters
==========
msg
Plaintext message of `n` upper-case letters.
key
A `k \times k` invertible matrix `K`, all of whose entries are
in `Z_{26}` (or whatever number of symbols are being used).
pad
Character (default "Q") to use to make length of text be a
multiple of ``k``.
Returns
=======
ct
Ciphertext of upper-case letters.
Notes
=====
ALGORITHM:
STEPS:
0. Number the letters of the alphabet from 0, ..., N
1. Compute from the string ``msg`` a list ``L`` of
corresponding integers. Let ``n = len(L)``.
2. Break the list ``L`` up into ``t = ceiling(n/k)``
sublists ``L_1``, ..., ``L_t`` of size ``k`` (with
the last list "padded" to ensure its size is
``k``).
3. Compute new list ``C_1``, ..., ``C_t`` given by
``C[i] = K*L_i`` (arithmetic is done mod N), for each
``i``.
4. Concatenate these into a list ``C = C_1 + ... + C_t``.
5. Compute from ``C`` a string ``ct`` of corresponding
letters. This has length ``k*t``.
References
==========
.. [1] https://en.wikipedia.org/wiki/Hill_cipher
.. [2] Lester S. Hill, Cryptography in an Algebraic Alphabet,
The American Mathematical Monthly Vol.36, June-July 1929,
pp.306-312.
See Also
========
decipher_hill
"""
assert key.is_square
assert len(pad) == 1
msg, pad, A = _prep(msg, pad, symbols)
map = {c: i for i, c in enumerate(A)}
P = [map[c] for c in msg]
N = len(A)
k = key.cols
n = len(P)
m, r = divmod(n, k)
if r:
P = P + [map[pad]]*(k - r)
m += 1
rv = ''.join([A[c % N] for j in range(m) for c in
list(key*Matrix(k, 1, [P[i]
for i in range(k*j, k*(j + 1))]))])
return rv
def decipher_hill(msg, key, symbols=None):
"""
Deciphering is the same as enciphering but using the inverse of the
key matrix.
Examples
========
>>> from sympy.crypto.crypto import encipher_hill, decipher_hill
>>> from sympy import Matrix
>>> key = Matrix([[1, 2], [3, 5]])
>>> encipher_hill("meet me on monday", key)
'UEQDUEODOCTCWQ'
>>> decipher_hill(_, key)
'MEETMEONMONDAY'
When the length of the plaintext (stripped of invalid characters)
is not a multiple of the key dimension, extra characters will
appear at the end of the enciphered and deciphered text. In order to
decipher the text, those characters must be included in the text to
be deciphered. In the following, the key has a dimension of 4 but
the text is 2 short of being a multiple of 4 so two characters will
be added.
>>> key = Matrix([[1, 1, 1, 2], [0, 1, 1, 0],
... [2, 2, 3, 4], [1, 1, 0, 1]])
>>> msg = "ST"
>>> encipher_hill(msg, key)
'HJEB'
>>> decipher_hill(_, key)
'STQQ'
>>> encipher_hill(msg, key, pad="Z")
'ISPK'
>>> decipher_hill(_, key)
'STZZ'
If the last two characters of the ciphertext were ignored in
either case, the wrong plaintext would be recovered:
>>> decipher_hill("HD", key)
'ORMV'
>>> decipher_hill("IS", key)
'UIKY'
See Also
========
encipher_hill
"""
assert key.is_square
msg, _, A = _prep(msg, '', symbols)
map = {c: i for i, c in enumerate(A)}
C = [map[c] for c in msg]
N = len(A)
k = key.cols
n = len(C)
m, r = divmod(n, k)
if r:
C = C + [0]*(k - r)
m += 1
key_inv = key.inv_mod(N)
rv = ''.join([A[p % N] for j in range(m) for p in
list(key_inv*Matrix(
k, 1, [C[i] for i in range(k*j, k*(j + 1))]))])
return rv
#################### Bifid cipher ########################
def encipher_bifid(msg, key, symbols=None):
r"""
Performs the Bifid cipher encryption on plaintext ``msg``, and
returns the ciphertext.
This is the version of the Bifid cipher that uses an `n \times n`
Polybius square.
Parameters
==========
msg
Plaintext string.
key
Short string for key.
Duplicate characters are ignored and then it is padded with the
characters in ``symbols`` that were not in the short key.
symbols
`n \times n` characters defining the alphabet.
(default is string.printable)
Returns
=======
ciphertext
Ciphertext using Bifid5 cipher without spaces.
See Also
========
decipher_bifid, encipher_bifid5, encipher_bifid6
References
==========
.. [1] https://en.wikipedia.org/wiki/Bifid_cipher
"""
msg, key, A = _prep(msg, key, symbols, bifid10)
long_key = ''.join(uniq(key)) or A
n = len(A)**.5
if n != int(n):
raise ValueError(
'Length of alphabet (%s) is not a square number.' % len(A))
N = int(n)
if len(long_key) < N**2:
long_key = list(long_key) + [x for x in A if x not in long_key]
# the fractionalization
row_col = {ch: divmod(i, N) for i, ch in enumerate(long_key)}
r, c = zip(*[row_col[x] for x in msg])
rc = r + c
ch = {i: ch for ch, i in row_col.items()}
rv = ''.join(ch[i] for i in zip(rc[::2], rc[1::2]))
return rv
def decipher_bifid(msg, key, symbols=None):
r"""
Performs the Bifid cipher decryption on ciphertext ``msg``, and
returns the plaintext.
This is the version of the Bifid cipher that uses the `n \times n`
Polybius square.
Parameters
==========
msg
Ciphertext string.
key
Short string for key.
Duplicate characters are ignored and then it is padded with the
characters in symbols that were not in the short key.
symbols
`n \times n` characters defining the alphabet.
(default=string.printable, a `10 \times 10` matrix)
Returns
=======
deciphered
Deciphered text.
Examples
========
>>> from sympy.crypto.crypto import (
... encipher_bifid, decipher_bifid, AZ)
Do an encryption using the bifid5 alphabet:
>>> alp = AZ().replace('J', '')
>>> ct = AZ("meet me on monday!")
>>> key = AZ("gold bug")
>>> encipher_bifid(ct, key, alp)
'IEILHHFSTSFQYE'
When entering the text or ciphertext, spaces are ignored so it
can be formatted as desired. Re-entering the ciphertext from the
preceding, putting 4 characters per line and padding with an extra
J, does not cause problems for the deciphering:
>>> decipher_bifid('''
... IEILH
... HFSTS
... FQYEJ''', key, alp)
'MEETMEONMONDAY'
When no alphabet is given, all 100 printable characters will be
used:
>>> key = ''
>>> encipher_bifid('hello world!', key)
'bmtwmg-bIo*w'
>>> decipher_bifid(_, key)
'hello world!'
If the key is changed, a different encryption is obtained:
>>> key = 'gold bug'
>>> encipher_bifid('hello world!', 'gold_bug')
'hg2sfuei7t}w'
And if the key used to decrypt the message is not exact, the
original text will not be perfectly obtained:
>>> decipher_bifid(_, 'gold pug')
'heldo~wor6d!'
"""
msg, _, A = _prep(msg, '', symbols, bifid10)
long_key = ''.join(uniq(key)) or A
n = len(A)**.5
if n != int(n):
raise ValueError(
'Length of alphabet (%s) is not a square number.' % len(A))
N = int(n)
if len(long_key) < N**2:
long_key = list(long_key) + [x for x in A if x not in long_key]
# the reverse fractionalization
row_col = {
ch: divmod(i, N) for i, ch in enumerate(long_key)}
rc = [i for c in msg for i in row_col[c]]
n = len(msg)
rc = zip(*(rc[:n], rc[n:]))
ch = {i: ch for ch, i in row_col.items()}
rv = ''.join(ch[i] for i in rc)
return rv
def bifid_square(key):
"""Return characters of ``key`` arranged in a square.
Examples
========
>>> from sympy.crypto.crypto import (
... bifid_square, AZ, padded_key, bifid5)
>>> bifid_square(AZ().replace('J', ''))
Matrix([
[A, B, C, D, E],
[F, G, H, I, K],
[L, M, N, O, P],
[Q, R, S, T, U],
[V, W, X, Y, Z]])
>>> bifid_square(padded_key(AZ('gold bug!'), bifid5))
Matrix([
[G, O, L, D, B],
[U, A, C, E, F],
[H, I, K, M, N],
[P, Q, R, S, T],
[V, W, X, Y, Z]])
See Also
========
padded_key
"""
A = ''.join(uniq(''.join(key)))
n = len(A)**.5
if n != int(n):
raise ValueError(
'Length of alphabet (%s) is not a square number.' % len(A))
n = int(n)
f = lambda i, j: Symbol(A[n*i + j])
rv = Matrix(n, n, f)
return rv
def encipher_bifid5(msg, key):
r"""
Performs the Bifid cipher encryption on plaintext ``msg``, and
returns the ciphertext.
Explanation
===========
This is the version of the Bifid cipher that uses the `5 \times 5`
Polybius square. The letter "J" is ignored so it must be replaced
with something else (traditionally an "I") before encryption.
ALGORITHM: (5x5 case)
STEPS:
0. Create the `5 \times 5` Polybius square ``S`` associated
to ``key`` as follows:
a) moving from left-to-right, top-to-bottom,
place the letters of the key into a `5 \times 5`
matrix,
b) if the key has less than 25 letters, add the
letters of the alphabet not in the key until the
`5 \times 5` square is filled.
1. Create a list ``P`` of pairs of numbers which are the
coordinates in the Polybius square of the letters in
``msg``.
2. Let ``L1`` be the list of all first coordinates of ``P``
(length of ``L1 = n``), let ``L2`` be the list of all
second coordinates of ``P`` (so the length of ``L2``
is also ``n``).
3. Let ``L`` be the concatenation of ``L1`` and ``L2``
(length ``L = 2*n``), except that consecutive numbers
are paired ``(L[2*i], L[2*i + 1])``. You can regard
``L`` as a list of pairs of length ``n``.
4. Let ``C`` be the list of all letters which are of the
form ``S[i, j]``, for all ``(i, j)`` in ``L``. As a
string, this is the ciphertext of ``msg``.
Parameters
==========
msg : str
Plaintext string.
Converted to upper case and filtered of anything but all letters
except J.
key
Short string for key; non-alphabetic letters, J and duplicated
characters are ignored and then, if the length is less than 25
characters, it is padded with other letters of the alphabet
(in alphabetical order).
Returns
=======
ct
Ciphertext (all caps, no spaces).
Examples
========
>>> from sympy.crypto.crypto import (
... encipher_bifid5, decipher_bifid5)
"J" will be omitted unless it is replaced with something else:
>>> round_trip = lambda m, k: \
... decipher_bifid5(encipher_bifid5(m, k), k)
>>> key = 'a'
>>> msg = "JOSIE"
>>> round_trip(msg, key)
'OSIE'
>>> round_trip(msg.replace("J", "I"), key)
'IOSIE'
>>> j = "QIQ"
>>> round_trip(msg.replace("J", j), key).replace(j, "J")
'JOSIE'
Notes
=====
The Bifid cipher was invented around 1901 by Felix Delastelle.
It is a *fractional substitution* cipher, where letters are
replaced by pairs of symbols from a smaller alphabet. The
cipher uses a `5 \times 5` square filled with some ordering of the
alphabet, except that "J" is replaced with "I" (this is a so-called
Polybius square; there is a `6 \times 6` analog if you add back in
"J" and also append onto the usual 26 letter alphabet, the digits
0, 1, ..., 9).
According to Helen Gaines' book *Cryptanalysis*, this type of cipher
was used in the field by the German Army during World War I.
See Also
========
decipher_bifid5, encipher_bifid
"""
msg, key, _ = _prep(msg.upper(), key.upper(), None, bifid5)
key = padded_key(key, bifid5)
return encipher_bifid(msg, '', key)
def decipher_bifid5(msg, key):
r"""
Return the Bifid cipher decryption of ``msg``.
Explanation
===========
This is the version of the Bifid cipher that uses the `5 \times 5`
Polybius square; the letter "J" is ignored unless a ``key`` of
length 25 is used.
Parameters
==========
msg
Ciphertext string.
key
Short string for key; duplicated characters are ignored and if
the length is less then 25 characters, it will be padded with
other letters from the alphabet omitting "J".
Non-alphabetic characters are ignored.
Returns
=======
plaintext
Plaintext from Bifid5 cipher (all caps, no spaces).
Examples
========
>>> from sympy.crypto.crypto import encipher_bifid5, decipher_bifid5
>>> key = "gold bug"
>>> encipher_bifid5('meet me on friday', key)
'IEILEHFSTSFXEE'
>>> encipher_bifid5('meet me on monday', key)
'IEILHHFSTSFQYE'
>>> decipher_bifid5(_, key)
'MEETMEONMONDAY'
"""
msg, key, _ = _prep(msg.upper(), key.upper(), None, bifid5)
key = padded_key(key, bifid5)
return decipher_bifid(msg, '', key)
def bifid5_square(key=None):
r"""
5x5 Polybius square.
Produce the Polybius square for the `5 \times 5` Bifid cipher.
Examples
========
>>> from sympy.crypto.crypto import bifid5_square
>>> bifid5_square("gold bug")
Matrix([
[G, O, L, D, B],
[U, A, C, E, F],
[H, I, K, M, N],
[P, Q, R, S, T],
[V, W, X, Y, Z]])
"""
if not key:
key = bifid5
else:
_, key, _ = _prep('', key.upper(), None, bifid5)
key = padded_key(key, bifid5)
return bifid_square(key)
def encipher_bifid6(msg, key):
r"""
Performs the Bifid cipher encryption on plaintext ``msg``, and
returns the ciphertext.
This is the version of the Bifid cipher that uses the `6 \times 6`
Polybius square.
Parameters
==========
msg
Plaintext string (digits okay).
key
Short string for key (digits okay).
If ``key`` is less than 36 characters long, the square will be
filled with letters A through Z and digits 0 through 9.
Returns
=======
ciphertext
Ciphertext from Bifid cipher (all caps, no spaces).
See Also
========
decipher_bifid6, encipher_bifid
"""
msg, key, _ = _prep(msg.upper(), key.upper(), None, bifid6)
key = padded_key(key, bifid6)
return encipher_bifid(msg, '', key)
def decipher_bifid6(msg, key):
r"""
Performs the Bifid cipher decryption on ciphertext ``msg``, and
returns the plaintext.
This is the version of the Bifid cipher that uses the `6 \times 6`
Polybius square.
Parameters
==========
msg
Ciphertext string (digits okay); converted to upper case
key
Short string for key (digits okay).
If ``key`` is less than 36 characters long, the square will be
filled with letters A through Z and digits 0 through 9.
All letters are converted to uppercase.
Returns
=======
plaintext
Plaintext from Bifid cipher (all caps, no spaces).
Examples
========
>>> from sympy.crypto.crypto import encipher_bifid6, decipher_bifid6
>>> key = "gold bug"
>>> encipher_bifid6('meet me on monday at 8am', key)
'KFKLJJHF5MMMKTFRGPL'
>>> decipher_bifid6(_, key)
'MEETMEONMONDAYAT8AM'
"""
msg, key, _ = _prep(msg.upper(), key.upper(), None, bifid6)
key = padded_key(key, bifid6)
return decipher_bifid(msg, '', key)
def bifid6_square(key=None):
r"""
6x6 Polybius square.
Produces the Polybius square for the `6 \times 6` Bifid cipher.
Assumes alphabet of symbols is "A", ..., "Z", "0", ..., "9".
Examples
========
>>> from sympy.crypto.crypto import bifid6_square
>>> key = "gold bug"
>>> bifid6_square(key)
Matrix([
[G, O, L, D, B, U],
[A, C, E, F, H, I],
[J, K, M, N, P, Q],
[R, S, T, V, W, X],
[Y, Z, 0, 1, 2, 3],
[4, 5, 6, 7, 8, 9]])
"""
if not key:
key = bifid6
else:
_, key, _ = _prep('', key.upper(), None, bifid6)
key = padded_key(key, bifid6)
return bifid_square(key)
#################### RSA #############################
def _decipher_rsa_crt(i, d, factors):
"""Decipher RSA using chinese remainder theorem from the information
of the relatively-prime factors of the modulus.
Parameters
==========
i : integer
Ciphertext
d : integer
The exponent component.
factors : list of relatively-prime integers
The integers given must be coprime and the product must equal
the modulus component of the original RSA key.
Examples
========
How to decrypt RSA with CRT:
>>> from sympy.crypto.crypto import rsa_public_key, rsa_private_key
>>> primes = [61, 53]
>>> e = 17
>>> args = primes + [e]
>>> puk = rsa_public_key(*args)
>>> prk = rsa_private_key(*args)
>>> from sympy.crypto.crypto import encipher_rsa, _decipher_rsa_crt
>>> msg = 65
>>> crt_primes = primes
>>> encrypted = encipher_rsa(msg, puk)
>>> decrypted = _decipher_rsa_crt(encrypted, prk[1], primes)
>>> decrypted
65
"""
moduluses = [pow(i, d, p) for p in factors]
result = crt(factors, moduluses)
if not result:
raise ValueError("CRT failed")
return result[0]
def _rsa_key(*args, public=True, private=True, totient='Euler', index=None, multipower=None):
r"""A private subroutine to generate RSA key
Parameters
==========
public, private : bool, optional
Flag to generate either a public key, a private key.
totient : 'Euler' or 'Carmichael'
Different notation used for totient.
multipower : bool, optional
Flag to bypass warning for multipower RSA.
"""
if len(args) < 2:
return False
if totient not in ('Euler', 'Carmichael'):
raise ValueError(
"The argument totient={} should either be " \
"'Euler', 'Carmichalel'." \
.format(totient))
if totient == 'Euler':
_totient = _euler
else:
_totient = _carmichael
if index is not None:
index = as_int(index)
if totient != 'Carmichael':
raise ValueError(
"Setting the 'index' keyword argument requires totient"
"notation to be specified as 'Carmichael'.")
primes, e = args[:-1], args[-1]
if not all(isprime(p) for p in primes):
new_primes = []
for i in primes:
new_primes.extend(factorint(i, multiple=True))
primes = new_primes
n = reduce(lambda i, j: i*j, primes)
tally = multiset(primes)
if all(v == 1 for v in tally.values()):
phi = int(_totient(tally))
else:
if not multipower:
NonInvertibleCipherWarning(
'Non-distinctive primes found in the factors {}. '
'The cipher may not be decryptable for some numbers '
'in the complete residue system Z[{}], but the cipher '
'can still be valid if you restrict the domain to be '
'the reduced residue system Z*[{}]. You can pass '
'the flag multipower=True if you want to suppress this '
'warning.'
.format(primes, n, n)
# stacklevel=4 because most users will call a function that
# calls this function
).warn(stacklevel=4)
phi = int(_totient(tally))
if gcd(e, phi) == 1:
if public and not private:
if isinstance(index, int):
e = e % phi
e += index * phi
return n, e
if private and not public:
d = invert(e, phi)
if isinstance(index, int):
d += index * phi
return n, d
return False
def rsa_public_key(*args, **kwargs):
r"""Return the RSA *public key* pair, `(n, e)`
Parameters
==========
args : naturals
If specified as `p, q, e` where `p` and `q` are distinct primes
and `e` is a desired public exponent of the RSA, `n = p q` and
`e` will be verified against the totient
`\phi(n)` (Euler totient) or `\lambda(n)` (Carmichael totient)
to be `\gcd(e, \phi(n)) = 1` or `\gcd(e, \lambda(n)) = 1`.
If specified as `p_1, p_2, \dots, p_n, e` where
`p_1, p_2, \dots, p_n` are specified as primes,
and `e` is specified as a desired public exponent of the RSA,
it will be able to form a multi-prime RSA, which is a more
generalized form of the popular 2-prime RSA.
It can also be possible to form a single-prime RSA by specifying
the argument as `p, e`, which can be considered a trivial case
of a multiprime RSA.
Furthermore, it can be possible to form a multi-power RSA by
specifying two or more pairs of the primes to be same.
However, unlike the two-distinct prime RSA or multi-prime
RSA, not every numbers in the complete residue system
(`\mathbb{Z}_n`) will be decryptable since the mapping
`\mathbb{Z}_{n} \rightarrow \mathbb{Z}_{n}`
will not be bijective.
(Only except for the trivial case when
`e = 1`
or more generally,
.. math::
e \in \left \{ 1 + k \lambda(n)
\mid k \in \mathbb{Z} \land k \geq 0 \right \}
when RSA reduces to the identity.)
However, the RSA can still be decryptable for the numbers in the
reduced residue system (`\mathbb{Z}_n^{\times}`), since the
mapping
`\mathbb{Z}_{n}^{\times} \rightarrow \mathbb{Z}_{n}^{\times}`
can still be bijective.
If you pass a non-prime integer to the arguments
`p_1, p_2, \dots, p_n`, the particular number will be
prime-factored and it will become either a multi-prime RSA or a
multi-power RSA in its canonical form, depending on whether the
product equals its radical or not.
`p_1 p_2 \dots p_n = \text{rad}(p_1 p_2 \dots p_n)`
totient : bool, optional
If ``'Euler'``, it uses Euler's totient `\phi(n)` which is
:meth:`sympy.functions.combinatorial.numbers.totient` in SymPy.
If ``'Carmichael'``, it uses Carmichael's totient `\lambda(n)`
which is :meth:`sympy.functions.combinatorial.numbers.reduced_totient` in SymPy.
Unlike private key generation, this is a trivial keyword for
public key generation because
`\gcd(e, \phi(n)) = 1 \iff \gcd(e, \lambda(n)) = 1`.
index : nonnegative integer, optional
Returns an arbitrary solution of a RSA public key at the index
specified at `0, 1, 2, \dots`. This parameter needs to be
specified along with ``totient='Carmichael'``.
Similarly to the non-uniquenss of a RSA private key as described
in the ``index`` parameter documentation in
:meth:`rsa_private_key`, RSA public key is also not unique and
there is an infinite number of RSA public exponents which
can behave in the same manner.
From any given RSA public exponent `e`, there are can be an
another RSA public exponent `e + k \lambda(n)` where `k` is an
integer, `\lambda` is a Carmichael's totient function.
However, considering only the positive cases, there can be
a principal solution of a RSA public exponent `e_0` in
`0 < e_0 < \lambda(n)`, and all the other solutions
can be canonicalzed in a form of `e_0 + k \lambda(n)`.
``index`` specifies the `k` notation to yield any possible value
an RSA public key can have.
An example of computing any arbitrary RSA public key:
>>> from sympy.crypto.crypto import rsa_public_key
>>> rsa_public_key(61, 53, 17, totient='Carmichael', index=0)
(3233, 17)
>>> rsa_public_key(61, 53, 17, totient='Carmichael', index=1)
(3233, 797)
>>> rsa_public_key(61, 53, 17, totient='Carmichael', index=2)
(3233, 1577)
multipower : bool, optional
Any pair of non-distinct primes found in the RSA specification
will restrict the domain of the cryptosystem, as noted in the
explanation of the parameter ``args``.
SymPy RSA key generator may give a warning before dispatching it
as a multi-power RSA, however, you can disable the warning if
you pass ``True`` to this keyword.
Returns
=======
(n, e) : int, int
`n` is a product of any arbitrary number of primes given as
the argument.
`e` is relatively prime (coprime) to the Euler totient
`\phi(n)`.
False
Returned if less than two arguments are given, or `e` is
not relatively prime to the modulus.
Examples
========
>>> from sympy.crypto.crypto import rsa_public_key
A public key of a two-prime RSA:
>>> p, q, e = 3, 5, 7
>>> rsa_public_key(p, q, e)
(15, 7)
>>> rsa_public_key(p, q, 30)
False
A public key of a multiprime RSA:
>>> primes = [2, 3, 5, 7, 11, 13]
>>> e = 7
>>> args = primes + [e]
>>> rsa_public_key(*args)
(30030, 7)
Notes
=====
Although the RSA can be generalized over any modulus `n`, using
two large primes had became the most popular specification because a
product of two large primes is usually the hardest to factor
relatively to the digits of `n` can have.
However, it may need further understanding of the time complexities
of each prime-factoring algorithms to verify the claim.
See Also
========
rsa_private_key
encipher_rsa
decipher_rsa
References
==========
.. [1] https://en.wikipedia.org/wiki/RSA_%28cryptosystem%29
.. [2] https://cacr.uwaterloo.ca/techreports/2006/cacr2006-16.pdf
.. [3] https://link.springer.com/content/pdf/10.1007/BFb0055738.pdf
.. [4] https://www.itiis.org/digital-library/manuscript/1381
"""
return _rsa_key(*args, public=True, private=False, **kwargs)
def rsa_private_key(*args, **kwargs):
r"""Return the RSA *private key* pair, `(n, d)`
Parameters
==========
args : naturals
The keyword is identical to the ``args`` in
:meth:`rsa_public_key`.
totient : bool, optional
If ``'Euler'``, it uses Euler's totient convention `\phi(n)`
which is :meth:`sympy.functions.combinatorial.numbers.totient` in SymPy.
If ``'Carmichael'``, it uses Carmichael's totient convention
`\lambda(n)` which is
:meth:`sympy.functions.combinatorial.numbers.reduced_totient` in SymPy.
There can be some output differences for private key generation
as examples below.
Example using Euler's totient:
>>> from sympy.crypto.crypto import rsa_private_key
>>> rsa_private_key(61, 53, 17, totient='Euler')
(3233, 2753)
Example using Carmichael's totient:
>>> from sympy.crypto.crypto import rsa_private_key
>>> rsa_private_key(61, 53, 17, totient='Carmichael')
(3233, 413)
index : nonnegative integer, optional
Returns an arbitrary solution of a RSA private key at the index
specified at `0, 1, 2, \dots`. This parameter needs to be
specified along with ``totient='Carmichael'``.
RSA private exponent is a non-unique solution of
`e d \mod \lambda(n) = 1` and it is possible in any form of
`d + k \lambda(n)`, where `d` is an another
already-computed private exponent, and `\lambda` is a
Carmichael's totient function, and `k` is any integer.
However, considering only the positive cases, there can be
a principal solution of a RSA private exponent `d_0` in
`0 < d_0 < \lambda(n)`, and all the other solutions
can be canonicalzed in a form of `d_0 + k \lambda(n)`.
``index`` specifies the `k` notation to yield any possible value
an RSA private key can have.
An example of computing any arbitrary RSA private key:
>>> from sympy.crypto.crypto import rsa_private_key
>>> rsa_private_key(61, 53, 17, totient='Carmichael', index=0)
(3233, 413)
>>> rsa_private_key(61, 53, 17, totient='Carmichael', index=1)
(3233, 1193)
>>> rsa_private_key(61, 53, 17, totient='Carmichael', index=2)
(3233, 1973)
multipower : bool, optional
The keyword is identical to the ``multipower`` in
:meth:`rsa_public_key`.
Returns
=======
(n, d) : int, int
`n` is a product of any arbitrary number of primes given as
the argument.
`d` is the inverse of `e` (mod `\phi(n)`) where `e` is the
exponent given, and `\phi` is a Euler totient.
False
Returned if less than two arguments are given, or `e` is
not relatively prime to the totient of the modulus.
Examples
========
>>> from sympy.crypto.crypto import rsa_private_key
A private key of a two-prime RSA:
>>> p, q, e = 3, 5, 7
>>> rsa_private_key(p, q, e)
(15, 7)
>>> rsa_private_key(p, q, 30)
False
A private key of a multiprime RSA:
>>> primes = [2, 3, 5, 7, 11, 13]
>>> e = 7
>>> args = primes + [e]
>>> rsa_private_key(*args)
(30030, 823)
See Also
========
rsa_public_key
encipher_rsa
decipher_rsa
References
==========
.. [1] https://en.wikipedia.org/wiki/RSA_%28cryptosystem%29
.. [2] https://cacr.uwaterloo.ca/techreports/2006/cacr2006-16.pdf
.. [3] https://link.springer.com/content/pdf/10.1007/BFb0055738.pdf
.. [4] https://www.itiis.org/digital-library/manuscript/1381
"""
return _rsa_key(*args, public=False, private=True, **kwargs)
def _encipher_decipher_rsa(i, key, factors=None):
n, d = key
if not factors:
return pow(i, d, n)
def _is_coprime_set(l):
is_coprime_set = True
for i in range(len(l)):
for j in range(i+1, len(l)):
if gcd(l[i], l[j]) != 1:
is_coprime_set = False
break
return is_coprime_set
prod = reduce(lambda i, j: i*j, factors)
if prod == n and _is_coprime_set(factors):
return _decipher_rsa_crt(i, d, factors)
return _encipher_decipher_rsa(i, key, factors=None)
def encipher_rsa(i, key, factors=None):
r"""Encrypt the plaintext with RSA.
Parameters
==========
i : integer
The plaintext to be encrypted for.
key : (n, e) where n, e are integers
`n` is the modulus of the key and `e` is the exponent of the
key. The encryption is computed by `i^e \bmod n`.
The key can either be a public key or a private key, however,
the message encrypted by a public key can only be decrypted by
a private key, and vice versa, as RSA is an asymmetric
cryptography system.
factors : list of coprime integers
This is identical to the keyword ``factors`` in
:meth:`decipher_rsa`.
Notes
=====
Some specifications may make the RSA not cryptographically
meaningful.
For example, `0`, `1` will remain always same after taking any
number of exponentiation, thus, should be avoided.
Furthermore, if `i^e < n`, `i` may easily be figured out by taking
`e` th root.
And also, specifying the exponent as `1` or in more generalized form
as `1 + k \lambda(n)` where `k` is an nonnegative integer,
`\lambda` is a carmichael totient, the RSA becomes an identity
mapping.
Examples
========
>>> from sympy.crypto.crypto import encipher_rsa
>>> from sympy.crypto.crypto import rsa_public_key, rsa_private_key
Public Key Encryption:
>>> p, q, e = 3, 5, 7
>>> puk = rsa_public_key(p, q, e)
>>> msg = 12
>>> encipher_rsa(msg, puk)
3
Private Key Encryption:
>>> p, q, e = 3, 5, 7
>>> prk = rsa_private_key(p, q, e)
>>> msg = 12
>>> encipher_rsa(msg, prk)
3
Encryption using chinese remainder theorem:
>>> encipher_rsa(msg, prk, factors=[p, q])
3
"""
return _encipher_decipher_rsa(i, key, factors=factors)
def decipher_rsa(i, key, factors=None):
r"""Decrypt the ciphertext with RSA.
Parameters
==========
i : integer
The ciphertext to be decrypted for.
key : (n, d) where n, d are integers
`n` is the modulus of the key and `d` is the exponent of the
key. The decryption is computed by `i^d \bmod n`.
The key can either be a public key or a private key, however,
the message encrypted by a public key can only be decrypted by
a private key, and vice versa, as RSA is an asymmetric
cryptography system.
factors : list of coprime integers
As the modulus `n` created from RSA key generation is composed
of arbitrary prime factors
`n = {p_1}^{k_1}{p_2}^{k_2}\dots{p_n}^{k_n}` where
`p_1, p_2, \dots, p_n` are distinct primes and
`k_1, k_2, \dots, k_n` are positive integers, chinese remainder
theorem can be used to compute `i^d \bmod n` from the
fragmented modulo operations like
.. math::
i^d \bmod {p_1}^{k_1}, i^d \bmod {p_2}^{k_2}, \dots,
i^d \bmod {p_n}^{k_n}
or like
.. math::
i^d \bmod {p_1}^{k_1}{p_2}^{k_2},
i^d \bmod {p_3}^{k_3}, \dots ,
i^d \bmod {p_n}^{k_n}
as long as every moduli does not share any common divisor each
other.
The raw primes used in generating the RSA key pair can be a good
option.
Note that the speed advantage of using this is only viable for
very large cases (Like 2048-bit RSA keys) since the
overhead of using pure Python implementation of
:meth:`sympy.ntheory.modular.crt` may overcompensate the
theoretical speed advantage.
Notes
=====
See the ``Notes`` section in the documentation of
:meth:`encipher_rsa`
Examples
========
>>> from sympy.crypto.crypto import decipher_rsa, encipher_rsa
>>> from sympy.crypto.crypto import rsa_public_key, rsa_private_key
Public Key Encryption and Decryption:
>>> p, q, e = 3, 5, 7
>>> prk = rsa_private_key(p, q, e)
>>> puk = rsa_public_key(p, q, e)
>>> msg = 12
>>> new_msg = encipher_rsa(msg, prk)
>>> new_msg
3
>>> decipher_rsa(new_msg, puk)
12
Private Key Encryption and Decryption:
>>> p, q, e = 3, 5, 7
>>> prk = rsa_private_key(p, q, e)
>>> puk = rsa_public_key(p, q, e)
>>> msg = 12
>>> new_msg = encipher_rsa(msg, puk)
>>> new_msg
3
>>> decipher_rsa(new_msg, prk)
12
Decryption using chinese remainder theorem:
>>> decipher_rsa(new_msg, prk, factors=[p, q])
12
See Also
========
encipher_rsa
"""
return _encipher_decipher_rsa(i, key, factors=factors)
#################### kid krypto (kid RSA) #############################
def kid_rsa_public_key(a, b, A, B):
r"""
Kid RSA is a version of RSA useful to teach grade school children
since it does not involve exponentiation.
Explanation
===========
Alice wants to talk to Bob. Bob generates keys as follows.
Key generation:
* Select positive integers `a, b, A, B` at random.
* Compute `M = a b - 1`, `e = A M + a`, `d = B M + b`,
`n = (e d - 1)//M`.
* The *public key* is `(n, e)`. Bob sends these to Alice.
* The *private key* is `(n, d)`, which Bob keeps secret.
Encryption: If `p` is the plaintext message then the
ciphertext is `c = p e \pmod n`.
Decryption: If `c` is the ciphertext message then the
plaintext is `p = c d \pmod n`.
Examples
========
>>> from sympy.crypto.crypto import kid_rsa_public_key
>>> a, b, A, B = 3, 4, 5, 6
>>> kid_rsa_public_key(a, b, A, B)
(369, 58)
"""
M = a*b - 1
e = A*M + a
d = B*M + b
n = (e*d - 1)//M
return n, e
def kid_rsa_private_key(a, b, A, B):
"""
Compute `M = a b - 1`, `e = A M + a`, `d = B M + b`,
`n = (e d - 1) / M`. The *private key* is `d`, which Bob
keeps secret.
Examples
========
>>> from sympy.crypto.crypto import kid_rsa_private_key
>>> a, b, A, B = 3, 4, 5, 6
>>> kid_rsa_private_key(a, b, A, B)
(369, 70)
"""
M = a*b - 1
e = A*M + a
d = B*M + b
n = (e*d - 1)//M
return n, d
def encipher_kid_rsa(msg, key):
"""
Here ``msg`` is the plaintext and ``key`` is the public key.
Examples
========
>>> from sympy.crypto.crypto import (
... encipher_kid_rsa, kid_rsa_public_key)
>>> msg = 200
>>> a, b, A, B = 3, 4, 5, 6
>>> key = kid_rsa_public_key(a, b, A, B)
>>> encipher_kid_rsa(msg, key)
161
"""
n, e = key
return (msg*e) % n
def decipher_kid_rsa(msg, key):
"""
Here ``msg`` is the plaintext and ``key`` is the private key.
Examples
========
>>> from sympy.crypto.crypto import (
... kid_rsa_public_key, kid_rsa_private_key,
... decipher_kid_rsa, encipher_kid_rsa)
>>> a, b, A, B = 3, 4, 5, 6
>>> d = kid_rsa_private_key(a, b, A, B)
>>> msg = 200
>>> pub = kid_rsa_public_key(a, b, A, B)
>>> pri = kid_rsa_private_key(a, b, A, B)
>>> ct = encipher_kid_rsa(msg, pub)
>>> decipher_kid_rsa(ct, pri)
200
"""
n, d = key
return (msg*d) % n
#################### Morse Code ######################################
morse_char = {
".-": "A", "-...": "B",
"-.-.": "C", "-..": "D",
".": "E", "..-.": "F",
"--.": "G", "....": "H",
"..": "I", ".---": "J",
"-.-": "K", ".-..": "L",
"--": "M", "-.": "N",
"---": "O", ".--.": "P",
"--.-": "Q", ".-.": "R",
"...": "S", "-": "T",
"..-": "U", "...-": "V",
".--": "W", "-..-": "X",
"-.--": "Y", "--..": "Z",
"-----": "0", ".----": "1",
"..---": "2", "...--": "3",
"....-": "4", ".....": "5",
"-....": "6", "--...": "7",
"---..": "8", "----.": "9",
".-.-.-": ".", "--..--": ",",
"---...": ":", "-.-.-.": ";",
"..--..": "?", "-....-": "-",
"..--.-": "_", "-.--.": "(",
"-.--.-": ")", ".----.": "'",
"-...-": "=", ".-.-.": "+",
"-..-.": "/", ".--.-.": "@",
"...-..-": "$", "-.-.--": "!"}
char_morse = {v: k for k, v in morse_char.items()}
def encode_morse(msg, sep='|', mapping=None):
"""
Encodes a plaintext into popular Morse Code with letters
separated by ``sep`` and words by a double ``sep``.
Examples
========
>>> from sympy.crypto.crypto import encode_morse
>>> msg = 'ATTACK RIGHT FLANK'
>>> encode_morse(msg)
'.-|-|-|.-|-.-.|-.-||.-.|..|--.|....|-||..-.|.-..|.-|-.|-.-'
References
==========
.. [1] https://en.wikipedia.org/wiki/Morse_code
"""
mapping = mapping or char_morse
assert sep not in mapping
word_sep = 2*sep
mapping[" "] = word_sep
suffix = msg and msg[-1] in whitespace
# normalize whitespace
msg = (' ' if word_sep else '').join(msg.split())
# omit unmapped chars
chars = set(''.join(msg.split()))
ok = set(mapping.keys())
msg = translate(msg, None, ''.join(chars - ok))
morsestring = []
words = msg.split()
for word in words:
morseword = []
for letter in word:
morseletter = mapping[letter]
morseword.append(morseletter)
word = sep.join(morseword)
morsestring.append(word)
return word_sep.join(morsestring) + (word_sep if suffix else '')
def decode_morse(msg, sep='|', mapping=None):
"""
Decodes a Morse Code with letters separated by ``sep``
(default is '|') and words by `word_sep` (default is '||)
into plaintext.
Examples
========
>>> from sympy.crypto.crypto import decode_morse
>>> mc = '--|---|...-|.||.|.-|...|-'
>>> decode_morse(mc)
'MOVE EAST'
References
==========
.. [1] https://en.wikipedia.org/wiki/Morse_code
"""
mapping = mapping or morse_char
word_sep = 2*sep
characterstring = []
words = msg.strip(word_sep).split(word_sep)
for word in words:
letters = word.split(sep)
chars = [mapping[c] for c in letters]
word = ''.join(chars)
characterstring.append(word)
rv = " ".join(characterstring)
return rv
#################### LFSRs ##########################################
@doctest_depends_on(ground_types=['python', 'gmpy'])
def lfsr_sequence(key, fill, n):
r"""
This function creates an LFSR sequence.
Parameters
==========
key : list
A list of finite field elements, `[c_0, c_1, \ldots, c_k].`
fill : list
The list of the initial terms of the LFSR sequence,
`[x_0, x_1, \ldots, x_k].`
n
Number of terms of the sequence that the function returns.
Returns
=======
L
The LFSR sequence defined by
`x_{n+1} = c_k x_n + \ldots + c_0 x_{n-k}`, for
`n \leq k`.
Notes
=====
S. Golomb [G]_ gives a list of three statistical properties a
sequence of numbers `a = \{a_n\}_{n=1}^\infty`,
`a_n \in \{0,1\}`, should display to be considered
"random". Define the autocorrelation of `a` to be
.. math::
C(k) = C(k,a) = \lim_{N\rightarrow \infty} {1\over N}\sum_{n=1}^N (-1)^{a_n + a_{n+k}}.
In the case where `a` is periodic with period
`P` then this reduces to
.. math::
C(k) = {1\over P}\sum_{n=1}^P (-1)^{a_n + a_{n+k}}.
Assume `a` is periodic with period `P`.
- balance:
.. math::
\left|\sum_{n=1}^P(-1)^{a_n}\right| \leq 1.
- low autocorrelation:
.. math::
C(k) = \left\{ \begin{array}{cc} 1,& k = 0,\\ \epsilon, & k \ne 0. \end{array} \right.
(For sequences satisfying these first two properties, it is known
that `\epsilon = -1/P` must hold.)
- proportional runs property: In each period, half the runs have
length `1`, one-fourth have length `2`, etc.
Moreover, there are as many runs of `1`'s as there are of
`0`'s.
Examples
========
>>> from sympy.crypto.crypto import lfsr_sequence
>>> from sympy.polys.domains import FF
>>> F = FF(2)
>>> fill = [F(1), F(1), F(0), F(1)]
>>> key = [F(1), F(0), F(0), F(1)]
>>> lfsr_sequence(key, fill, 10)
[1 mod 2, 1 mod 2, 0 mod 2, 1 mod 2, 0 mod 2,
1 mod 2, 1 mod 2, 0 mod 2, 0 mod 2, 1 mod 2]
References
==========
.. [G] Solomon Golomb, Shift register sequences, Aegean Park Press,
Laguna Hills, Ca, 1967
"""
if not isinstance(key, list):
raise TypeError("key must be a list")
if not isinstance(fill, list):
raise TypeError("fill must be a list")
p = key[0].modulus()
F = FF(p)
s = fill
k = len(fill)
L = []
for i in range(n):
s0 = s[:]
L.append(s[0])
s = s[1:k]
x = sum(int(key[i]*s0[i]) for i in range(k))
s.append(F(x))
return L # use [int(x) for x in L] for int version
def lfsr_autocorrelation(L, P, k):
"""
This function computes the LFSR autocorrelation function.
Parameters
==========
L
A periodic sequence of elements of `GF(2)`.
L must have length larger than P.
P
The period of L.
k : int
An integer `k` (`0 < k < P`).
Returns
=======
autocorrelation
The k-th value of the autocorrelation of the LFSR L.
Examples
========
>>> from sympy.crypto.crypto import (
... lfsr_sequence, lfsr_autocorrelation)
>>> from sympy.polys.domains import FF
>>> F = FF(2)
>>> fill = [F(1), F(1), F(0), F(1)]
>>> key = [F(1), F(0), F(0), F(1)]
>>> s = lfsr_sequence(key, fill, 20)
>>> lfsr_autocorrelation(s, 15, 7)
-1/15
>>> lfsr_autocorrelation(s, 15, 0)
1
"""
if not isinstance(L, list):
raise TypeError("L (=%s) must be a list" % L)
P = int(P)
k = int(k)
L0 = L[:P] # slices makes a copy
L1 = L0 + L0[:k]
L2 = [(-1)**(int(L1[i]) + int(L1[i + k])) for i in range(P)]
tot = sum(L2)
return Rational(tot, P)
def lfsr_connection_polynomial(s):
"""
This function computes the LFSR connection polynomial.
Parameters
==========
s
A sequence of elements of even length, with entries in a finite
field.
Returns
=======
C(x)
The connection polynomial of a minimal LFSR yielding s.
This implements the algorithm in section 3 of J. L. Massey's
article [M]_.
Examples
========
>>> from sympy.crypto.crypto import (
... lfsr_sequence, lfsr_connection_polynomial)
>>> from sympy.polys.domains import FF
>>> F = FF(2)
>>> fill = [F(1), F(1), F(0), F(1)]
>>> key = [F(1), F(0), F(0), F(1)]
>>> s = lfsr_sequence(key, fill, 20)
>>> lfsr_connection_polynomial(s)
x**4 + x + 1
>>> fill = [F(1), F(0), F(0), F(1)]
>>> key = [F(1), F(1), F(0), F(1)]
>>> s = lfsr_sequence(key, fill, 20)
>>> lfsr_connection_polynomial(s)
x**3 + 1
>>> fill = [F(1), F(0), F(1)]
>>> key = [F(1), F(1), F(0)]
>>> s = lfsr_sequence(key, fill, 20)
>>> lfsr_connection_polynomial(s)
x**3 + x**2 + 1
>>> fill = [F(1), F(0), F(1)]
>>> key = [F(1), F(0), F(1)]
>>> s = lfsr_sequence(key, fill, 20)
>>> lfsr_connection_polynomial(s)
x**3 + x + 1
References
==========
.. [M] James L. Massey, "Shift-Register Synthesis and BCH Decoding."
IEEE Trans. on Information Theory, vol. 15(1), pp. 122-127,
Jan 1969.
"""
# Initialization:
p = s[0].modulus()
x = Symbol("x")
C = 1*x**0
B = 1*x**0
m = 1
b = 1*x**0
L = 0
N = 0
while N < len(s):
if L > 0:
dC = Poly(C).degree()
r = min(L + 1, dC + 1)
coeffsC = [C.subs(x, 0)] + [C.coeff(x**i)
for i in range(1, dC + 1)]
d = (int(s[N]) + sum(coeffsC[i]*int(s[N - i])
for i in range(1, r))) % p
if L == 0:
d = int(s[N])*x**0
if d == 0:
m += 1
N += 1
if d > 0:
if 2*L > N:
C = (C - d*((b**(p - 2)) % p)*x**m*B).expand()
m += 1
N += 1
else:
T = C
C = (C - d*((b**(p - 2)) % p)*x**m*B).expand()
L = N + 1 - L
m = 1
b = d
B = T
N += 1
dC = Poly(C).degree()
coeffsC = [C.subs(x, 0)] + [C.coeff(x**i) for i in range(1, dC + 1)]
return sum(coeffsC[i] % p*x**i for i in range(dC + 1)
if coeffsC[i] is not None)
#################### ElGamal #############################
def elgamal_private_key(digit=10, seed=None):
r"""
Return three number tuple as private key.
Explanation
===========
Elgamal encryption is based on the mathematical problem
called the Discrete Logarithm Problem (DLP). For example,
`a^{b} \equiv c \pmod p`
In general, if ``a`` and ``b`` are known, ``ct`` is easily
calculated. If ``b`` is unknown, it is hard to use
``a`` and ``ct`` to get ``b``.
Parameters
==========
digit : int
Minimum number of binary digits for key.
Returns
=======
tuple : (p, r, d)
p = prime number.
r = primitive root.
d = random number.
Notes
=====
For testing purposes, the ``seed`` parameter may be set to control
the output of this routine. See sympy.core.random._randrange.
Examples
========
>>> from sympy.crypto.crypto import elgamal_private_key
>>> from sympy.ntheory import is_primitive_root, isprime
>>> a, b, _ = elgamal_private_key()
>>> isprime(a)
True
>>> is_primitive_root(b, a)
True
"""
randrange = _randrange(seed)
p = nextprime(2**digit)
return p, primitive_root(p), randrange(2, p)
def elgamal_public_key(key):
r"""
Return three number tuple as public key.
Parameters
==========
key : (p, r, e)
Tuple generated by ``elgamal_private_key``.
Returns
=======
tuple : (p, r, e)
`e = r**d \bmod p`
`d` is a random number in private key.
Examples
========
>>> from sympy.crypto.crypto import elgamal_public_key
>>> elgamal_public_key((1031, 14, 636))
(1031, 14, 212)
"""
p, r, e = key
return p, r, pow(r, e, p)
def encipher_elgamal(i, key, seed=None):
r"""
Encrypt message with public key.
Explanation
===========
``i`` is a plaintext message expressed as an integer.
``key`` is public key (p, r, e). In order to encrypt
a message, a random number ``a`` in ``range(2, p)``
is generated and the encryped message is returned as
`c_{1}` and `c_{2}` where:
`c_{1} \equiv r^{a} \pmod p`
`c_{2} \equiv m e^{a} \pmod p`
Parameters
==========
msg
int of encoded message.
key
Public key.
Returns
=======
tuple : (c1, c2)
Encipher into two number.
Notes
=====
For testing purposes, the ``seed`` parameter may be set to control
the output of this routine. See sympy.core.random._randrange.
Examples
========
>>> from sympy.crypto.crypto import encipher_elgamal, elgamal_private_key, elgamal_public_key
>>> pri = elgamal_private_key(5, seed=[3]); pri
(37, 2, 3)
>>> pub = elgamal_public_key(pri); pub
(37, 2, 8)
>>> msg = 36
>>> encipher_elgamal(msg, pub, seed=[3])
(8, 6)
"""
p, r, e = key
if i < 0 or i >= p:
raise ValueError(
'Message (%s) should be in range(%s)' % (i, p))
randrange = _randrange(seed)
a = randrange(2, p)
return pow(r, a, p), i*pow(e, a, p) % p
def decipher_elgamal(msg, key):
r"""
Decrypt message with private key.
`msg = (c_{1}, c_{2})`
`key = (p, r, d)`
According to extended Eucliden theorem,
`u c_{1}^{d} + p n = 1`
`u \equiv 1/{{c_{1}}^d} \pmod p`
`u c_{2} \equiv \frac{1}{c_{1}^d} c_{2} \equiv \frac{1}{r^{ad}} c_{2} \pmod p`
`\frac{1}{r^{ad}} m e^a \equiv \frac{1}{r^{ad}} m {r^{d a}} \equiv m \pmod p`
Examples
========
>>> from sympy.crypto.crypto import decipher_elgamal
>>> from sympy.crypto.crypto import encipher_elgamal
>>> from sympy.crypto.crypto import elgamal_private_key
>>> from sympy.crypto.crypto import elgamal_public_key
>>> pri = elgamal_private_key(5, seed=[3])
>>> pub = elgamal_public_key(pri); pub
(37, 2, 8)
>>> msg = 17
>>> decipher_elgamal(encipher_elgamal(msg, pub), pri) == msg
True
"""
p, _, d = key
c1, c2 = msg
u = pow(c1, -d, p)
return u * c2 % p
################ Diffie-Hellman Key Exchange #########################
def dh_private_key(digit=10, seed=None):
r"""
Return three integer tuple as private key.
Explanation
===========
Diffie-Hellman key exchange is based on the mathematical problem
called the Discrete Logarithm Problem (see ElGamal).
Diffie-Hellman key exchange is divided into the following steps:
* Alice and Bob agree on a base that consist of a prime ``p``
and a primitive root of ``p`` called ``g``
* Alice choses a number ``a`` and Bob choses a number ``b`` where
``a`` and ``b`` are random numbers in range `[2, p)`. These are
their private keys.
* Alice then publicly sends Bob `g^{a} \pmod p` while Bob sends
Alice `g^{b} \pmod p`
* They both raise the received value to their secretly chosen
number (``a`` or ``b``) and now have both as their shared key
`g^{ab} \pmod p`
Parameters
==========
digit
Minimum number of binary digits required in key.
Returns
=======
tuple : (p, g, a)
p = prime number.
g = primitive root of p.
a = random number from 2 through p - 1.
Notes
=====
For testing purposes, the ``seed`` parameter may be set to control
the output of this routine. See sympy.core.random._randrange.
Examples
========
>>> from sympy.crypto.crypto import dh_private_key
>>> from sympy.ntheory import isprime, is_primitive_root
>>> p, g, _ = dh_private_key()
>>> isprime(p)
True
>>> is_primitive_root(g, p)
True
>>> p, g, _ = dh_private_key(5)
>>> isprime(p)
True
>>> is_primitive_root(g, p)
True
"""
p = nextprime(2**digit)
g = primitive_root(p)
randrange = _randrange(seed)
a = randrange(2, p)
return p, g, a
def dh_public_key(key):
r"""
Return three number tuple as public key.
This is the tuple that Alice sends to Bob.
Parameters
==========
key : (p, g, a)
A tuple generated by ``dh_private_key``.
Returns
=======
tuple : int, int, int
A tuple of `(p, g, g^a \mod p)` with `p`, `g` and `a` given as
parameters.s
Examples
========
>>> from sympy.crypto.crypto import dh_private_key, dh_public_key
>>> p, g, a = dh_private_key();
>>> _p, _g, x = dh_public_key((p, g, a))
>>> p == _p and g == _g
True
>>> x == pow(g, a, p)
True
"""
p, g, a = key
return p, g, pow(g, a, p)
def dh_shared_key(key, b):
"""
Return an integer that is the shared key.
This is what Bob and Alice can both calculate using the public
keys they received from each other and their private keys.
Parameters
==========
key : (p, g, x)
Tuple `(p, g, x)` generated by ``dh_public_key``.
b
Random number in the range of `2` to `p - 1`
(Chosen by second key exchange member (Bob)).
Returns
=======
int
A shared key.
Examples
========
>>> from sympy.crypto.crypto import (
... dh_private_key, dh_public_key, dh_shared_key)
>>> prk = dh_private_key();
>>> p, g, x = dh_public_key(prk);
>>> sk = dh_shared_key((p, g, x), 1000)
>>> sk == pow(x, 1000, p)
True
"""
p, _, x = key
if 1 >= b or b >= p:
raise ValueError(filldedent('''
Value of b should be greater 1 and less
than prime %s.''' % p))
return pow(x, b, p)
################ Goldwasser-Micali Encryption #########################
def _legendre(a, p):
"""
Returns the legendre symbol of a and p
assuming that p is a prime.
i.e. 1 if a is a quadratic residue mod p
-1 if a is not a quadratic residue mod p
0 if a is divisible by p
Parameters
==========
a : int
The number to test.
p : prime
The prime to test ``a`` against.
Returns
=======
int
Legendre symbol (a / p).
"""
sig = pow(a, (p - 1)//2, p)
if sig == 1:
return 1
elif sig == 0:
return 0
else:
return -1
def _random_coprime_stream(n, seed=None):
randrange = _randrange(seed)
while True:
y = randrange(n)
if gcd(y, n) == 1:
yield y
def gm_private_key(p, q, a=None):
r"""
Check if ``p`` and ``q`` can be used as private keys for
the Goldwasser-Micali encryption. The method works
roughly as follows.
Explanation
===========
#. Pick two large primes $p$ and $q$.
#. Call their product $N$.
#. Given a message as an integer $i$, write $i$ in its bit representation $b_0, \dots, b_n$.
#. For each $k$,
if $b_k = 0$:
let $a_k$ be a random square
(quadratic residue) modulo $p q$
such that ``jacobi_symbol(a, p*q) = 1``
if $b_k = 1$:
let $a_k$ be a random non-square
(non-quadratic residue) modulo $p q$
such that ``jacobi_symbol(a, p*q) = 1``
returns $\left[a_1, a_2, \dots\right]$
$b_k$ can be recovered by checking whether or not
$a_k$ is a residue. And from the $b_k$'s, the message
can be reconstructed.
The idea is that, while ``jacobi_symbol(a, p*q)``
can be easily computed (and when it is equal to $-1$ will
tell you that $a$ is not a square mod $p q$), quadratic
residuosity modulo a composite number is hard to compute
without knowing its factorization.
Moreover, approximately half the numbers coprime to $p q$ have
:func:`~.jacobi_symbol` equal to $1$ . And among those, approximately half
are residues and approximately half are not. This maximizes the
entropy of the code.
Parameters
==========
p, q, a
Initialization variables.
Returns
=======
tuple : (p, q)
The input value ``p`` and ``q``.
Raises
======
ValueError
If ``p`` and ``q`` are not distinct odd primes.
"""
if p == q:
raise ValueError("expected distinct primes, "
"got two copies of %i" % p)
elif not isprime(p) or not isprime(q):
raise ValueError("first two arguments must be prime, "
"got %i of %i" % (p, q))
elif p == 2 or q == 2:
raise ValueError("first two arguments must not be even, "
"got %i of %i" % (p, q))
return p, q
def gm_public_key(p, q, a=None, seed=None):
"""
Compute public keys for ``p`` and ``q``.
Note that in Goldwasser-Micali Encryption,
public keys are randomly selected.
Parameters
==========
p, q, a : int, int, int
Initialization variables.
Returns
=======
tuple : (a, N)
``a`` is the input ``a`` if it is not ``None`` otherwise
some random integer coprime to ``p`` and ``q``.
``N`` is the product of ``p`` and ``q``.
"""
p, q = gm_private_key(p, q)
N = p * q
if a is None:
randrange = _randrange(seed)
while True:
a = randrange(N)
if _legendre(a, p) == _legendre(a, q) == -1:
break
else:
if _legendre(a, p) != -1 or _legendre(a, q) != -1:
return False
return (a, N)
def encipher_gm(i, key, seed=None):
"""
Encrypt integer 'i' using public_key 'key'
Note that gm uses random encryption.
Parameters
==========
i : int
The message to encrypt.
key : (a, N)
The public key.
Returns
=======
list : list of int
The randomized encrypted message.
"""
if i < 0:
raise ValueError(
"message must be a non-negative "
"integer: got %d instead" % i)
a, N = key
bits = []
while i > 0:
bits.append(i % 2)
i //= 2
gen = _random_coprime_stream(N, seed)
rev = reversed(bits)
encode = lambda b: next(gen)**2*pow(a, b) % N
return [ encode(b) for b in rev ]
def decipher_gm(message, key):
"""
Decrypt message 'message' using public_key 'key'.
Parameters
==========
message : list of int
The randomized encrypted message.
key : (p, q)
The private key.
Returns
=======
int
The encrypted message.
"""
p, q = key
res = lambda m, p: _legendre(m, p) > 0
bits = [res(m, p) * res(m, q) for m in message]
m = 0
for b in bits:
m <<= 1
m += not b
return m
########### RailFence Cipher #############
def encipher_railfence(message,rails):
"""
Performs Railfence Encryption on plaintext and returns ciphertext
Examples
========
>>> from sympy.crypto.crypto import encipher_railfence
>>> message = "hello world"
>>> encipher_railfence(message,3)
'horel ollwd'
Parameters
==========
message : string, the message to encrypt.
rails : int, the number of rails.
Returns
=======
The Encrypted string message.
References
==========
.. [1] https://en.wikipedia.org/wiki/Rail_fence_cipher
"""
r = list(range(rails))
p = cycle(r + r[-2:0:-1])
return ''.join(sorted(message, key=lambda i: next(p)))
def decipher_railfence(ciphertext,rails):
"""
Decrypt the message using the given rails
Examples
========
>>> from sympy.crypto.crypto import decipher_railfence
>>> decipher_railfence("horel ollwd",3)
'hello world'
Parameters
==========
message : string, the message to encrypt.
rails : int, the number of rails.
Returns
=======
The Decrypted string message.
"""
r = list(range(rails))
p = cycle(r + r[-2:0:-1])
idx = sorted(range(len(ciphertext)), key=lambda i: next(p))
res = [''] * len(ciphertext)
for i, c in zip(idx, ciphertext):
res[i] = c
return ''.join(res)
################ Blum-Goldwasser cryptosystem #########################
def bg_private_key(p, q):
"""
Check if p and q can be used as private keys for
the Blum-Goldwasser cryptosystem.
Explanation
===========
The three necessary checks for p and q to pass
so that they can be used as private keys:
1. p and q must both be prime
2. p and q must be distinct
3. p and q must be congruent to 3 mod 4
Parameters
==========
p, q
The keys to be checked.
Returns
=======
p, q
Input values.
Raises
======
ValueError
If p and q do not pass the above conditions.
"""
if not isprime(p) or not isprime(q):
raise ValueError("the two arguments must be prime, "
"got %i and %i" %(p, q))
elif p == q:
raise ValueError("the two arguments must be distinct, "
"got two copies of %i. " %p)
elif (p - 3) % 4 != 0 or (q - 3) % 4 != 0:
raise ValueError("the two arguments must be congruent to 3 mod 4, "
"got %i and %i" %(p, q))
return p, q
def bg_public_key(p, q):
"""
Calculates public keys from private keys.
Explanation
===========
The function first checks the validity of
private keys passed as arguments and
then returns their product.
Parameters
==========
p, q
The private keys.
Returns
=======
N
The public key.
"""
p, q = bg_private_key(p, q)
N = p * q
return N
def encipher_bg(i, key, seed=None):
"""
Encrypts the message using public key and seed.
Explanation
===========
ALGORITHM:
1. Encodes i as a string of L bits, m.
2. Select a random element r, where 1 < r < key, and computes
x = r^2 mod key.
3. Use BBS pseudo-random number generator to generate L random bits, b,
using the initial seed as x.
4. Encrypted message, c_i = m_i XOR b_i, 1 <= i <= L.
5. x_L = x^(2^L) mod key.
6. Return (c, x_L)
Parameters
==========
i
Message, a non-negative integer
key
The public key
Returns
=======
Tuple
(encrypted_message, x_L)
Raises
======
ValueError
If i is negative.
"""
if i < 0:
raise ValueError(
"message must be a non-negative "
"integer: got %d instead" % i)
enc_msg = []
while i > 0:
enc_msg.append(i % 2)
i //= 2
enc_msg.reverse()
L = len(enc_msg)
r = _randint(seed)(2, key - 1)
x = r**2 % key
x_L = pow(int(x), int(2**L), int(key))
rand_bits = []
for _ in range(L):
rand_bits.append(x % 2)
x = x**2 % key
encrypt_msg = [m ^ b for (m, b) in zip(enc_msg, rand_bits)]
return (encrypt_msg, x_L)
def decipher_bg(message, key):
"""
Decrypts the message using private keys.
Explanation
===========
ALGORITHM:
1. Let, c be the encrypted message, y the second number received,
and p and q be the private keys.
2. Compute, r_p = y^((p+1)/4 ^ L) mod p and
r_q = y^((q+1)/4 ^ L) mod q.
3. Compute x_0 = (q(q^-1 mod p)r_p + p(p^-1 mod q)r_q) mod N.
4. From, recompute the bits using the BBS generator, as in the
encryption algorithm.
5. Compute original message by XORing c and b.
Parameters
==========
message
Tuple of encrypted message and a non-negative integer.
key
Tuple of private keys.
Returns
=======
orig_msg
The original message
"""
p, q = key
encrypt_msg, y = message
public_key = p * q
L = len(encrypt_msg)
p_t = ((p + 1)/4)**L
q_t = ((q + 1)/4)**L
r_p = pow(int(y), int(p_t), int(p))
r_q = pow(int(y), int(q_t), int(q))
x = (q * invert(q, p) * r_p + p * invert(p, q) * r_q) % public_key
orig_bits = []
for _ in range(L):
orig_bits.append(x % 2)
x = x**2 % public_key
orig_msg = 0
for (m, b) in zip(encrypt_msg, orig_bits):
orig_msg = orig_msg * 2
orig_msg += (m ^ b)
return orig_msg
PK ]ZZZ���� � sympy/diffgeom/__init__.pyfrom .diffgeom import (
BaseCovarDerivativeOp, BaseScalarField, BaseVectorField, Commutator,
contravariant_order, CoordSystem, CoordinateSymbol,
CovarDerivativeOp, covariant_order, Differential, intcurve_diffequ,
intcurve_series, LieDerivative, Manifold, metric_to_Christoffel_1st,
metric_to_Christoffel_2nd, metric_to_Ricci_components,
metric_to_Riemann_components, Patch, Point, TensorProduct, twoform_to_matrix,
vectors_in_basis, WedgeProduct,
)
__all__ = [
'BaseCovarDerivativeOp', 'BaseScalarField', 'BaseVectorField', 'Commutator',
'contravariant_order', 'CoordSystem', 'CoordinateSymbol',
'CovarDerivativeOp', 'covariant_order', 'Differential', 'intcurve_diffequ',
'intcurve_series', 'LieDerivative', 'Manifold', 'metric_to_Christoffel_1st',
'metric_to_Christoffel_2nd', 'metric_to_Ricci_components',
'metric_to_Riemann_components', 'Patch', 'Point', 'TensorProduct',
'twoform_to_matrix', 'vectors_in_basis', 'WedgeProduct',
]
PK ]ZZZ�h��Q Q sympy/diffgeom/diffgeom.pyfrom __future__ import annotations
from typing import Any
from functools import reduce
from itertools import permutations
from sympy.combinatorics import Permutation
from sympy.core import (
Basic, Expr, Function, diff,
Pow, Mul, Add, Lambda, S, Tuple, Dict
)
from sympy.core.cache import cacheit
from sympy.core.symbol import Symbol, Dummy
from sympy.core.symbol import Str
from sympy.core.sympify import _sympify
from sympy.functions import factorial
from sympy.matrices import ImmutableDenseMatrix as Matrix
from sympy.solvers import solve
from sympy.utilities.exceptions import (sympy_deprecation_warning,
SymPyDeprecationWarning,
ignore_warnings)
# TODO you are a bit excessive in the use of Dummies
# TODO dummy point, literal field
# TODO too often one needs to call doit or simplify on the output, check the
# tests and find out why
from sympy.tensor.array import ImmutableDenseNDimArray
class Manifold(Basic):
"""
A mathematical manifold.
Explanation
===========
A manifold is a topological space that locally resembles
Euclidean space near each point [1].
This class does not provide any means to study the topological
characteristics of the manifold that it represents, though.
Parameters
==========
name : str
The name of the manifold.
dim : int
The dimension of the manifold.
Examples
========
>>> from sympy.diffgeom import Manifold
>>> m = Manifold('M', 2)
>>> m
M
>>> m.dim
2
References
==========
.. [1] https://en.wikipedia.org/wiki/Manifold
"""
def __new__(cls, name, dim, **kwargs):
if not isinstance(name, Str):
name = Str(name)
dim = _sympify(dim)
obj = super().__new__(cls, name, dim)
obj.patches = _deprecated_list(
"""
Manifold.patches is deprecated. The Manifold object is now
immutable. Instead use a separate list to keep track of the
patches.
""", [])
return obj
@property
def name(self):
return self.args[0]
@property
def dim(self):
return self.args[1]
class Patch(Basic):
"""
A patch on a manifold.
Explanation
===========
Coordinate patch, or patch in short, is a simply-connected open set around
a point in the manifold [1]. On a manifold one can have many patches that
do not always include the whole manifold. On these patches coordinate
charts can be defined that permit the parameterization of any point on the
patch in terms of a tuple of real numbers (the coordinates).
This class does not provide any means to study the topological
characteristics of the patch that it represents.
Parameters
==========
name : str
The name of the patch.
manifold : Manifold
The manifold on which the patch is defined.
Examples
========
>>> from sympy.diffgeom import Manifold, Patch
>>> m = Manifold('M', 2)
>>> p = Patch('P', m)
>>> p
P
>>> p.dim
2
References
==========
.. [1] G. Sussman, J. Wisdom, W. Farr, Functional Differential Geometry
(2013)
"""
def __new__(cls, name, manifold, **kwargs):
if not isinstance(name, Str):
name = Str(name)
obj = super().__new__(cls, name, manifold)
obj.manifold.patches.append(obj) # deprecated
obj.coord_systems = _deprecated_list(
"""
Patch.coord_systms is deprecated. The Patch class is now
immutable. Instead use a separate list to keep track of coordinate
systems.
""", [])
return obj
@property
def name(self):
return self.args[0]
@property
def manifold(self):
return self.args[1]
@property
def dim(self):
return self.manifold.dim
class CoordSystem(Basic):
"""
A coordinate system defined on the patch.
Explanation
===========
Coordinate system is a system that uses one or more coordinates to uniquely
determine the position of the points or other geometric elements on a
manifold [1].
By passing ``Symbols`` to *symbols* parameter, user can define the name and
assumptions of coordinate symbols of the coordinate system. If not passed,
these symbols are generated automatically and are assumed to be real valued.
By passing *relations* parameter, user can define the transform relations of
coordinate systems. Inverse transformation and indirect transformation can
be found automatically. If this parameter is not passed, coordinate
transformation cannot be done.
Parameters
==========
name : str
The name of the coordinate system.
patch : Patch
The patch where the coordinate system is defined.
symbols : list of Symbols, optional
Defines the names and assumptions of coordinate symbols.
relations : dict, optional
Key is a tuple of two strings, who are the names of the systems where
the coordinates transform from and transform to.
Value is a tuple of the symbols before transformation and a tuple of
the expressions after transformation.
Examples
========
We define two-dimensional Cartesian coordinate system and polar coordinate
system.
>>> from sympy import symbols, pi, sqrt, atan2, cos, sin
>>> from sympy.diffgeom import Manifold, Patch, CoordSystem
>>> m = Manifold('M', 2)
>>> p = Patch('P', m)
>>> x, y = symbols('x y', real=True)
>>> r, theta = symbols('r theta', nonnegative=True)
>>> relation_dict = {
... ('Car2D', 'Pol'): [(x, y), (sqrt(x**2 + y**2), atan2(y, x))],
... ('Pol', 'Car2D'): [(r, theta), (r*cos(theta), r*sin(theta))]
... }
>>> Car2D = CoordSystem('Car2D', p, (x, y), relation_dict)
>>> Pol = CoordSystem('Pol', p, (r, theta), relation_dict)
``symbols`` property returns ``CoordinateSymbol`` instances. These symbols
are not same with the symbols used to construct the coordinate system.
>>> Car2D
Car2D
>>> Car2D.dim
2
>>> Car2D.symbols
(x, y)
>>> _[0].func
<class 'sympy.diffgeom.diffgeom.CoordinateSymbol'>
``transformation()`` method returns the transformation function from
one coordinate system to another. ``transform()`` method returns the
transformed coordinates.
>>> Car2D.transformation(Pol)
Lambda((x, y), Matrix([
[sqrt(x**2 + y**2)],
[ atan2(y, x)]]))
>>> Car2D.transform(Pol)
Matrix([
[sqrt(x**2 + y**2)],
[ atan2(y, x)]])
>>> Car2D.transform(Pol, [1, 2])
Matrix([
[sqrt(5)],
[atan(2)]])
``jacobian()`` method returns the Jacobian matrix of coordinate
transformation between two systems. ``jacobian_determinant()`` method
returns the Jacobian determinant of coordinate transformation between two
systems.
>>> Pol.jacobian(Car2D)
Matrix([
[cos(theta), -r*sin(theta)],
[sin(theta), r*cos(theta)]])
>>> Pol.jacobian(Car2D, [1, pi/2])
Matrix([
[0, -1],
[1, 0]])
>>> Car2D.jacobian_determinant(Pol)
1/sqrt(x**2 + y**2)
>>> Car2D.jacobian_determinant(Pol, [1,0])
1
References
==========
.. [1] https://en.wikipedia.org/wiki/Coordinate_system
"""
def __new__(cls, name, patch, symbols=None, relations={}, **kwargs):
if not isinstance(name, Str):
name = Str(name)
# canonicallize the symbols
if symbols is None:
names = kwargs.get('names', None)
if names is None:
symbols = Tuple(
*[Symbol('%s_%s' % (name.name, i), real=True)
for i in range(patch.dim)]
)
else:
sympy_deprecation_warning(
f"""
The 'names' argument to CoordSystem is deprecated. Use 'symbols' instead. That
is, replace
CoordSystem(..., names={names})
with
CoordSystem(..., symbols=[{', '.join(["Symbol(" + repr(n) + ", real=True)" for n in names])}])
""",
deprecated_since_version="1.7",
active_deprecations_target="deprecated-diffgeom-mutable",
)
symbols = Tuple(
*[Symbol(n, real=True) for n in names]
)
else:
syms = []
for s in symbols:
if isinstance(s, Symbol):
syms.append(Symbol(s.name, **s._assumptions.generator))
elif isinstance(s, str):
sympy_deprecation_warning(
f"""
Passing a string as the coordinate symbol name to CoordSystem is deprecated.
Pass a Symbol with the appropriate name and assumptions instead.
That is, replace {s} with Symbol({s!r}, real=True).
""",
deprecated_since_version="1.7",
active_deprecations_target="deprecated-diffgeom-mutable",
)
syms.append(Symbol(s, real=True))
symbols = Tuple(*syms)
# canonicallize the relations
rel_temp = {}
for k,v in relations.items():
s1, s2 = k
if not isinstance(s1, Str):
s1 = Str(s1)
if not isinstance(s2, Str):
s2 = Str(s2)
key = Tuple(s1, s2)
# Old version used Lambda as a value.
if isinstance(v, Lambda):
v = (tuple(v.signature), tuple(v.expr))
else:
v = (tuple(v[0]), tuple(v[1]))
rel_temp[key] = v
relations = Dict(rel_temp)
# construct the object
obj = super().__new__(cls, name, patch, symbols, relations)
# Add deprecated attributes
obj.transforms = _deprecated_dict(
"""
CoordSystem.transforms is deprecated. The CoordSystem class is now
immutable. Use the 'relations' keyword argument to the
CoordSystems() constructor to specify relations.
""", {})
obj._names = [str(n) for n in symbols]
obj.patch.coord_systems.append(obj) # deprecated
obj._dummies = [Dummy(str(n)) for n in symbols] # deprecated
obj._dummy = Dummy()
return obj
@property
def name(self):
return self.args[0]
@property
def patch(self):
return self.args[1]
@property
def manifold(self):
return self.patch.manifold
@property
def symbols(self):
return tuple(CoordinateSymbol(self, i, **s._assumptions.generator)
for i,s in enumerate(self.args[2]))
@property
def relations(self):
return self.args[3]
@property
def dim(self):
return self.patch.dim
##########################################################################
# Finding transformation relation
##########################################################################
def transformation(self, sys):
"""
Return coordinate transformation function from *self* to *sys*.
Parameters
==========
sys : CoordSystem
Returns
=======
sympy.Lambda
Examples
========
>>> from sympy.diffgeom.rn import R2_r, R2_p
>>> R2_r.transformation(R2_p)
Lambda((x, y), Matrix([
[sqrt(x**2 + y**2)],
[ atan2(y, x)]]))
"""
signature = self.args[2]
key = Tuple(self.name, sys.name)
if self == sys:
expr = Matrix(self.symbols)
elif key in self.relations:
expr = Matrix(self.relations[key][1])
elif key[::-1] in self.relations:
expr = Matrix(self._inverse_transformation(sys, self))
else:
expr = Matrix(self._indirect_transformation(self, sys))
return Lambda(signature, expr)
@staticmethod
def _solve_inverse(sym1, sym2, exprs, sys1_name, sys2_name):
ret = solve(
[t[0] - t[1] for t in zip(sym2, exprs)],
list(sym1), dict=True)
if len(ret) == 0:
temp = "Cannot solve inverse relation from {} to {}."
raise NotImplementedError(temp.format(sys1_name, sys2_name))
elif len(ret) > 1:
temp = "Obtained multiple inverse relation from {} to {}."
raise ValueError(temp.format(sys1_name, sys2_name))
return ret[0]
@classmethod
def _inverse_transformation(cls, sys1, sys2):
# Find the transformation relation from sys2 to sys1
forward = sys1.transform(sys2)
inv_results = cls._solve_inverse(sys1.symbols, sys2.symbols, forward,
sys1.name, sys2.name)
signature = tuple(sys1.symbols)
return [inv_results[s] for s in signature]
@classmethod
@cacheit
def _indirect_transformation(cls, sys1, sys2):
# Find the transformation relation between two indirectly connected
# coordinate systems
rel = sys1.relations
path = cls._dijkstra(sys1, sys2)
transforms = []
for s1, s2 in zip(path, path[1:]):
if (s1, s2) in rel:
transforms.append(rel[(s1, s2)])
else:
sym2, inv_exprs = rel[(s2, s1)]
sym1 = tuple(Dummy() for i in sym2)
ret = cls._solve_inverse(sym2, sym1, inv_exprs, s2, s1)
ret = tuple(ret[s] for s in sym2)
transforms.append((sym1, ret))
syms = sys1.args[2]
exprs = syms
for newsyms, newexprs in transforms:
exprs = tuple(e.subs(zip(newsyms, exprs)) for e in newexprs)
return exprs
@staticmethod
def _dijkstra(sys1, sys2):
# Use Dijkstra algorithm to find the shortest path between two indirectly-connected
# coordinate systems
# return value is the list of the names of the systems.
relations = sys1.relations
graph = {}
for s1, s2 in relations.keys():
if s1 not in graph:
graph[s1] = {s2}
else:
graph[s1].add(s2)
if s2 not in graph:
graph[s2] = {s1}
else:
graph[s2].add(s1)
path_dict = {sys:[0, [], 0] for sys in graph} # minimum distance, path, times of visited
def visit(sys):
path_dict[sys][2] = 1
for newsys in graph[sys]:
distance = path_dict[sys][0] + 1
if path_dict[newsys][0] >= distance or not path_dict[newsys][1]:
path_dict[newsys][0] = distance
path_dict[newsys][1] = list(path_dict[sys][1])
path_dict[newsys][1].append(sys)
visit(sys1.name)
while True:
min_distance = max(path_dict.values(), key=lambda x:x[0])[0]
newsys = None
for sys, lst in path_dict.items():
if 0 < lst[0] <= min_distance and not lst[2]:
min_distance = lst[0]
newsys = sys
if newsys is None:
break
visit(newsys)
result = path_dict[sys2.name][1]
result.append(sys2.name)
if result == [sys2.name]:
raise KeyError("Two coordinate systems are not connected.")
return result
def connect_to(self, to_sys, from_coords, to_exprs, inverse=True, fill_in_gaps=False):
sympy_deprecation_warning(
"""
The CoordSystem.connect_to() method is deprecated. Instead,
generate a new instance of CoordSystem with the 'relations'
keyword argument (CoordSystem classes are now immutable).
""",
deprecated_since_version="1.7",
active_deprecations_target="deprecated-diffgeom-mutable",
)
from_coords, to_exprs = dummyfy(from_coords, to_exprs)
self.transforms[to_sys] = Matrix(from_coords), Matrix(to_exprs)
if inverse:
to_sys.transforms[self] = self._inv_transf(from_coords, to_exprs)
if fill_in_gaps:
self._fill_gaps_in_transformations()
@staticmethod
def _inv_transf(from_coords, to_exprs):
# Will be removed when connect_to is removed
inv_from = [i.as_dummy() for i in from_coords]
inv_to = solve(
[t[0] - t[1] for t in zip(inv_from, to_exprs)],
list(from_coords), dict=True)[0]
inv_to = [inv_to[fc] for fc in from_coords]
return Matrix(inv_from), Matrix(inv_to)
@staticmethod
def _fill_gaps_in_transformations():
# Will be removed when connect_to is removed
raise NotImplementedError
##########################################################################
# Coordinate transformations
##########################################################################
def transform(self, sys, coordinates=None):
"""
Return the result of coordinate transformation from *self* to *sys*.
If coordinates are not given, coordinate symbols of *self* are used.
Parameters
==========
sys : CoordSystem
coordinates : Any iterable, optional.
Returns
=======
sympy.ImmutableDenseMatrix containing CoordinateSymbol
Examples
========
>>> from sympy.diffgeom.rn import R2_r, R2_p
>>> R2_r.transform(R2_p)
Matrix([
[sqrt(x**2 + y**2)],
[ atan2(y, x)]])
>>> R2_r.transform(R2_p, [0, 1])
Matrix([
[ 1],
[pi/2]])
"""
if coordinates is None:
coordinates = self.symbols
if self != sys:
transf = self.transformation(sys)
coordinates = transf(*coordinates)
else:
coordinates = Matrix(coordinates)
return coordinates
def coord_tuple_transform_to(self, to_sys, coords):
"""Transform ``coords`` to coord system ``to_sys``."""
sympy_deprecation_warning(
"""
The CoordSystem.coord_tuple_transform_to() method is deprecated.
Use the CoordSystem.transform() method instead.
""",
deprecated_since_version="1.7",
active_deprecations_target="deprecated-diffgeom-mutable",
)
coords = Matrix(coords)
if self != to_sys:
with ignore_warnings(SymPyDeprecationWarning):
transf = self.transforms[to_sys]
coords = transf[1].subs(list(zip(transf[0], coords)))
return coords
def jacobian(self, sys, coordinates=None):
"""
Return the jacobian matrix of a transformation on given coordinates.
If coordinates are not given, coordinate symbols of *self* are used.
Parameters
==========
sys : CoordSystem
coordinates : Any iterable, optional.
Returns
=======
sympy.ImmutableDenseMatrix
Examples
========
>>> from sympy.diffgeom.rn import R2_r, R2_p
>>> R2_p.jacobian(R2_r)
Matrix([
[cos(theta), -rho*sin(theta)],
[sin(theta), rho*cos(theta)]])
>>> R2_p.jacobian(R2_r, [1, 0])
Matrix([
[1, 0],
[0, 1]])
"""
result = self.transform(sys).jacobian(self.symbols)
if coordinates is not None:
result = result.subs(list(zip(self.symbols, coordinates)))
return result
jacobian_matrix = jacobian
def jacobian_determinant(self, sys, coordinates=None):
"""
Return the jacobian determinant of a transformation on given
coordinates. If coordinates are not given, coordinate symbols of *self*
are used.
Parameters
==========
sys : CoordSystem
coordinates : Any iterable, optional.
Returns
=======
sympy.Expr
Examples
========
>>> from sympy.diffgeom.rn import R2_r, R2_p
>>> R2_r.jacobian_determinant(R2_p)
1/sqrt(x**2 + y**2)
>>> R2_r.jacobian_determinant(R2_p, [1, 0])
1
"""
return self.jacobian(sys, coordinates).det()
##########################################################################
# Points
##########################################################################
def point(self, coords):
"""Create a ``Point`` with coordinates given in this coord system."""
return Point(self, coords)
def point_to_coords(self, point):
"""Calculate the coordinates of a point in this coord system."""
return point.coords(self)
##########################################################################
# Base fields.
##########################################################################
def base_scalar(self, coord_index):
"""Return ``BaseScalarField`` that takes a point and returns one of the coordinates."""
return BaseScalarField(self, coord_index)
coord_function = base_scalar
def base_scalars(self):
"""Returns a list of all coordinate functions.
For more details see the ``base_scalar`` method of this class."""
return [self.base_scalar(i) for i in range(self.dim)]
coord_functions = base_scalars
def base_vector(self, coord_index):
"""Return a basis vector field.
The basis vector field for this coordinate system. It is also an
operator on scalar fields."""
return BaseVectorField(self, coord_index)
def base_vectors(self):
"""Returns a list of all base vectors.
For more details see the ``base_vector`` method of this class."""
return [self.base_vector(i) for i in range(self.dim)]
def base_oneform(self, coord_index):
"""Return a basis 1-form field.
The basis one-form field for this coordinate system. It is also an
operator on vector fields."""
return Differential(self.coord_function(coord_index))
def base_oneforms(self):
"""Returns a list of all base oneforms.
For more details see the ``base_oneform`` method of this class."""
return [self.base_oneform(i) for i in range(self.dim)]
class CoordinateSymbol(Symbol):
"""A symbol which denotes an abstract value of i-th coordinate of
the coordinate system with given context.
Explanation
===========
Each coordinates in coordinate system are represented by unique symbol,
such as x, y, z in Cartesian coordinate system.
You may not construct this class directly. Instead, use `symbols` method
of CoordSystem.
Parameters
==========
coord_sys : CoordSystem
index : integer
Examples
========
>>> from sympy import symbols, Lambda, Matrix, sqrt, atan2, cos, sin
>>> from sympy.diffgeom import Manifold, Patch, CoordSystem
>>> m = Manifold('M', 2)
>>> p = Patch('P', m)
>>> x, y = symbols('x y', real=True)
>>> r, theta = symbols('r theta', nonnegative=True)
>>> relation_dict = {
... ('Car2D', 'Pol'): Lambda((x, y), Matrix([sqrt(x**2 + y**2), atan2(y, x)])),
... ('Pol', 'Car2D'): Lambda((r, theta), Matrix([r*cos(theta), r*sin(theta)]))
... }
>>> Car2D = CoordSystem('Car2D', p, [x, y], relation_dict)
>>> Pol = CoordSystem('Pol', p, [r, theta], relation_dict)
>>> x, y = Car2D.symbols
``CoordinateSymbol`` contains its coordinate symbol and index.
>>> x.name
'x'
>>> x.coord_sys == Car2D
True
>>> x.index
0
>>> x.is_real
True
You can transform ``CoordinateSymbol`` into other coordinate system using
``rewrite()`` method.
>>> x.rewrite(Pol)
r*cos(theta)
>>> sqrt(x**2 + y**2).rewrite(Pol).simplify()
r
"""
def __new__(cls, coord_sys, index, **assumptions):
name = coord_sys.args[2][index].name
obj = super().__new__(cls, name, **assumptions)
obj.coord_sys = coord_sys
obj.index = index
return obj
def __getnewargs__(self):
return (self.coord_sys, self.index)
def _hashable_content(self):
return (
self.coord_sys, self.index
) + tuple(sorted(self.assumptions0.items()))
def _eval_rewrite(self, rule, args, **hints):
if isinstance(rule, CoordSystem):
return rule.transform(self.coord_sys)[self.index]
return super()._eval_rewrite(rule, args, **hints)
class Point(Basic):
"""Point defined in a coordinate system.
Explanation
===========
Mathematically, point is defined in the manifold and does not have any coordinates
by itself. Coordinate system is what imbues the coordinates to the point by coordinate
chart. However, due to the difficulty of realizing such logic, you must supply
a coordinate system and coordinates to define a Point here.
The usage of this object after its definition is independent of the
coordinate system that was used in order to define it, however due to
limitations in the simplification routines you can arrive at complicated
expressions if you use inappropriate coordinate systems.
Parameters
==========
coord_sys : CoordSystem
coords : list
The coordinates of the point.
Examples
========
>>> from sympy import pi
>>> from sympy.diffgeom import Point
>>> from sympy.diffgeom.rn import R2, R2_r, R2_p
>>> rho, theta = R2_p.symbols
>>> p = Point(R2_p, [rho, 3*pi/4])
>>> p.manifold == R2
True
>>> p.coords()
Matrix([
[ rho],
[3*pi/4]])
>>> p.coords(R2_r)
Matrix([
[-sqrt(2)*rho/2],
[ sqrt(2)*rho/2]])
"""
def __new__(cls, coord_sys, coords, **kwargs):
coords = Matrix(coords)
obj = super().__new__(cls, coord_sys, coords)
obj._coord_sys = coord_sys
obj._coords = coords
return obj
@property
def patch(self):
return self._coord_sys.patch
@property
def manifold(self):
return self._coord_sys.manifold
@property
def dim(self):
return self.manifold.dim
def coords(self, sys=None):
"""
Coordinates of the point in given coordinate system. If coordinate system
is not passed, it returns the coordinates in the coordinate system in which
the poin was defined.
"""
if sys is None:
return self._coords
else:
return self._coord_sys.transform(sys, self._coords)
@property
def free_symbols(self):
return self._coords.free_symbols
class BaseScalarField(Expr):
"""Base scalar field over a manifold for a given coordinate system.
Explanation
===========
A scalar field takes a point as an argument and returns a scalar.
A base scalar field of a coordinate system takes a point and returns one of
the coordinates of that point in the coordinate system in question.
To define a scalar field you need to choose the coordinate system and the
index of the coordinate.
The use of the scalar field after its definition is independent of the
coordinate system in which it was defined, however due to limitations in
the simplification routines you may arrive at more complicated
expression if you use unappropriate coordinate systems.
You can build complicated scalar fields by just building up SymPy
expressions containing ``BaseScalarField`` instances.
Parameters
==========
coord_sys : CoordSystem
index : integer
Examples
========
>>> from sympy import Function, pi
>>> from sympy.diffgeom import BaseScalarField
>>> from sympy.diffgeom.rn import R2_r, R2_p
>>> rho, _ = R2_p.symbols
>>> point = R2_p.point([rho, 0])
>>> fx, fy = R2_r.base_scalars()
>>> ftheta = BaseScalarField(R2_r, 1)
>>> fx(point)
rho
>>> fy(point)
0
>>> (fx**2+fy**2).rcall(point)
rho**2
>>> g = Function('g')
>>> fg = g(ftheta-pi)
>>> fg.rcall(point)
g(-pi)
"""
is_commutative = True
def __new__(cls, coord_sys, index, **kwargs):
index = _sympify(index)
obj = super().__new__(cls, coord_sys, index)
obj._coord_sys = coord_sys
obj._index = index
return obj
@property
def coord_sys(self):
return self.args[0]
@property
def index(self):
return self.args[1]
@property
def patch(self):
return self.coord_sys.patch
@property
def manifold(self):
return self.coord_sys.manifold
@property
def dim(self):
return self.manifold.dim
def __call__(self, *args):
"""Evaluating the field at a point or doing nothing.
If the argument is a ``Point`` instance, the field is evaluated at that
point. The field is returned itself if the argument is any other
object. It is so in order to have working recursive calling mechanics
for all fields (check the ``__call__`` method of ``Expr``).
"""
point = args[0]
if len(args) != 1 or not isinstance(point, Point):
return self
coords = point.coords(self._coord_sys)
# XXX Calling doit is necessary with all the Subs expressions
# XXX Calling simplify is necessary with all the trig expressions
return simplify(coords[self._index]).doit()
# XXX Workaround for limitations on the content of args
free_symbols: set[Any] = set()
class BaseVectorField(Expr):
r"""Base vector field over a manifold for a given coordinate system.
Explanation
===========
A vector field is an operator taking a scalar field and returning a
directional derivative (which is also a scalar field).
A base vector field is the same type of operator, however the derivation is
specifically done with respect to a chosen coordinate.
To define a base vector field you need to choose the coordinate system and
the index of the coordinate.
The use of the vector field after its definition is independent of the
coordinate system in which it was defined, however due to limitations in the
simplification routines you may arrive at more complicated expression if you
use unappropriate coordinate systems.
Parameters
==========
coord_sys : CoordSystem
index : integer
Examples
========
>>> from sympy import Function
>>> from sympy.diffgeom.rn import R2_p, R2_r
>>> from sympy.diffgeom import BaseVectorField
>>> from sympy import pprint
>>> x, y = R2_r.symbols
>>> rho, theta = R2_p.symbols
>>> fx, fy = R2_r.base_scalars()
>>> point_p = R2_p.point([rho, theta])
>>> point_r = R2_r.point([x, y])
>>> g = Function('g')
>>> s_field = g(fx, fy)
>>> v = BaseVectorField(R2_r, 1)
>>> pprint(v(s_field))
/ d \|
|---(g(x, xi))||
\dxi /|xi=y
>>> pprint(v(s_field).rcall(point_r).doit())
d
--(g(x, y))
dy
>>> pprint(v(s_field).rcall(point_p))
/ d \|
|---(g(rho*cos(theta), xi))||
\dxi /|xi=rho*sin(theta)
"""
is_commutative = False
def __new__(cls, coord_sys, index, **kwargs):
index = _sympify(index)
obj = super().__new__(cls, coord_sys, index)
obj._coord_sys = coord_sys
obj._index = index
return obj
@property
def coord_sys(self):
return self.args[0]
@property
def index(self):
return self.args[1]
@property
def patch(self):
return self.coord_sys.patch
@property
def manifold(self):
return self.coord_sys.manifold
@property
def dim(self):
return self.manifold.dim
def __call__(self, scalar_field):
"""Apply on a scalar field.
The action of a vector field on a scalar field is a directional
differentiation.
If the argument is not a scalar field an error is raised.
"""
if covariant_order(scalar_field) or contravariant_order(scalar_field):
raise ValueError('Only scalar fields can be supplied as arguments to vector fields.')
if scalar_field is None:
return self
base_scalars = list(scalar_field.atoms(BaseScalarField))
# First step: e_x(x+r**2) -> e_x(x) + 2*r*e_x(r)
d_var = self._coord_sys._dummy
# TODO: you need a real dummy function for the next line
d_funcs = [Function('_#_%s' % i)(d_var) for i,
b in enumerate(base_scalars)]
d_result = scalar_field.subs(list(zip(base_scalars, d_funcs)))
d_result = d_result.diff(d_var)
# Second step: e_x(x) -> 1 and e_x(r) -> cos(atan2(x, y))
coords = self._coord_sys.symbols
d_funcs_deriv = [f.diff(d_var) for f in d_funcs]
d_funcs_deriv_sub = []
for b in base_scalars:
jac = self._coord_sys.jacobian(b._coord_sys, coords)
d_funcs_deriv_sub.append(jac[b._index, self._index])
d_result = d_result.subs(list(zip(d_funcs_deriv, d_funcs_deriv_sub)))
# Remove the dummies
result = d_result.subs(list(zip(d_funcs, base_scalars)))
result = result.subs(list(zip(coords, self._coord_sys.coord_functions())))
return result.doit()
def _find_coords(expr):
# Finds CoordinateSystems existing in expr
fields = expr.atoms(BaseScalarField, BaseVectorField)
return {f._coord_sys for f in fields}
class Commutator(Expr):
r"""Commutator of two vector fields.
Explanation
===========
The commutator of two vector fields `v_1` and `v_2` is defined as the
vector field `[v_1, v_2]` that evaluated on each scalar field `f` is equal
to `v_1(v_2(f)) - v_2(v_1(f))`.
Examples
========
>>> from sympy.diffgeom.rn import R2_p, R2_r
>>> from sympy.diffgeom import Commutator
>>> from sympy import simplify
>>> fx, fy = R2_r.base_scalars()
>>> e_x, e_y = R2_r.base_vectors()
>>> e_r = R2_p.base_vector(0)
>>> c_xy = Commutator(e_x, e_y)
>>> c_xr = Commutator(e_x, e_r)
>>> c_xy
0
Unfortunately, the current code is not able to compute everything:
>>> c_xr
Commutator(e_x, e_rho)
>>> simplify(c_xr(fy**2))
-2*cos(theta)*y**2/(x**2 + y**2)
"""
def __new__(cls, v1, v2):
if (covariant_order(v1) or contravariant_order(v1) != 1
or covariant_order(v2) or contravariant_order(v2) != 1):
raise ValueError(
'Only commutators of vector fields are supported.')
if v1 == v2:
return S.Zero
coord_sys = set().union(*[_find_coords(v) for v in (v1, v2)])
if len(coord_sys) == 1:
# Only one coordinate systems is used, hence it is easy enough to
# actually evaluate the commutator.
if all(isinstance(v, BaseVectorField) for v in (v1, v2)):
return S.Zero
bases_1, bases_2 = [list(v.atoms(BaseVectorField))
for v in (v1, v2)]
coeffs_1 = [v1.expand().coeff(b) for b in bases_1]
coeffs_2 = [v2.expand().coeff(b) for b in bases_2]
res = 0
for c1, b1 in zip(coeffs_1, bases_1):
for c2, b2 in zip(coeffs_2, bases_2):
res += c1*b1(c2)*b2 - c2*b2(c1)*b1
return res
else:
obj = super().__new__(cls, v1, v2)
obj._v1 = v1 # deprecated assignment
obj._v2 = v2 # deprecated assignment
return obj
@property
def v1(self):
return self.args[0]
@property
def v2(self):
return self.args[1]
def __call__(self, scalar_field):
"""Apply on a scalar field.
If the argument is not a scalar field an error is raised.
"""
return self.v1(self.v2(scalar_field)) - self.v2(self.v1(scalar_field))
class Differential(Expr):
r"""Return the differential (exterior derivative) of a form field.
Explanation
===========
The differential of a form (i.e. the exterior derivative) has a complicated
definition in the general case.
The differential `df` of the 0-form `f` is defined for any vector field `v`
as `df(v) = v(f)`.
Examples
========
>>> from sympy import Function
>>> from sympy.diffgeom.rn import R2_r
>>> from sympy.diffgeom import Differential
>>> from sympy import pprint
>>> fx, fy = R2_r.base_scalars()
>>> e_x, e_y = R2_r.base_vectors()
>>> g = Function('g')
>>> s_field = g(fx, fy)
>>> dg = Differential(s_field)
>>> dg
d(g(x, y))
>>> pprint(dg(e_x))
/ d \|
|---(g(xi, y))||
\dxi /|xi=x
>>> pprint(dg(e_y))
/ d \|
|---(g(x, xi))||
\dxi /|xi=y
Applying the exterior derivative operator twice always results in:
>>> Differential(dg)
0
"""
is_commutative = False
def __new__(cls, form_field):
if contravariant_order(form_field):
raise ValueError(
'A vector field was supplied as an argument to Differential.')
if isinstance(form_field, Differential):
return S.Zero
else:
obj = super().__new__(cls, form_field)
obj._form_field = form_field # deprecated assignment
return obj
@property
def form_field(self):
return self.args[0]
def __call__(self, *vector_fields):
"""Apply on a list of vector_fields.
Explanation
===========
If the number of vector fields supplied is not equal to 1 + the order of
the form field inside the differential the result is undefined.
For 1-forms (i.e. differentials of scalar fields) the evaluation is
done as `df(v)=v(f)`. However if `v` is ``None`` instead of a vector
field, the differential is returned unchanged. This is done in order to
permit partial contractions for higher forms.
In the general case the evaluation is done by applying the form field
inside the differential on a list with one less elements than the number
of elements in the original list. Lowering the number of vector fields
is achieved through replacing each pair of fields by their
commutator.
If the arguments are not vectors or ``None``s an error is raised.
"""
if any((contravariant_order(a) != 1 or covariant_order(a)) and a is not None
for a in vector_fields):
raise ValueError('The arguments supplied to Differential should be vector fields or Nones.')
k = len(vector_fields)
if k == 1:
if vector_fields[0]:
return vector_fields[0].rcall(self._form_field)
return self
else:
# For higher form it is more complicated:
# Invariant formula:
# https://en.wikipedia.org/wiki/Exterior_derivative#Invariant_formula
# df(v1, ... vn) = +/- vi(f(v1..no i..vn))
# +/- f([vi,vj],v1..no i, no j..vn)
f = self._form_field
v = vector_fields
ret = 0
for i in range(k):
t = v[i].rcall(f.rcall(*v[:i] + v[i + 1:]))
ret += (-1)**i*t
for j in range(i + 1, k):
c = Commutator(v[i], v[j])
if c: # TODO this is ugly - the Commutator can be Zero and
# this causes the next line to fail
t = f.rcall(*(c,) + v[:i] + v[i + 1:j] + v[j + 1:])
ret += (-1)**(i + j)*t
return ret
class TensorProduct(Expr):
"""Tensor product of forms.
Explanation
===========
The tensor product permits the creation of multilinear functionals (i.e.
higher order tensors) out of lower order fields (e.g. 1-forms and vector
fields). However, the higher tensors thus created lack the interesting
features provided by the other type of product, the wedge product, namely
they are not antisymmetric and hence are not form fields.
Examples
========
>>> from sympy.diffgeom.rn import R2_r
>>> from sympy.diffgeom import TensorProduct
>>> fx, fy = R2_r.base_scalars()
>>> e_x, e_y = R2_r.base_vectors()
>>> dx, dy = R2_r.base_oneforms()
>>> TensorProduct(dx, dy)(e_x, e_y)
1
>>> TensorProduct(dx, dy)(e_y, e_x)
0
>>> TensorProduct(dx, fx*dy)(fx*e_x, e_y)
x**2
>>> TensorProduct(e_x, e_y)(fx**2, fy**2)
4*x*y
>>> TensorProduct(e_y, dx)(fy)
dx
You can nest tensor products.
>>> tp1 = TensorProduct(dx, dy)
>>> TensorProduct(tp1, dx)(e_x, e_y, e_x)
1
You can make partial contraction for instance when 'raising an index'.
Putting ``None`` in the second argument of ``rcall`` means that the
respective position in the tensor product is left as it is.
>>> TP = TensorProduct
>>> metric = TP(dx, dx) + 3*TP(dy, dy)
>>> metric.rcall(e_y, None)
3*dy
Or automatically pad the args with ``None`` without specifying them.
>>> metric.rcall(e_y)
3*dy
"""
def __new__(cls, *args):
scalar = Mul(*[m for m in args if covariant_order(m) + contravariant_order(m) == 0])
multifields = [m for m in args if covariant_order(m) + contravariant_order(m)]
if multifields:
if len(multifields) == 1:
return scalar*multifields[0]
return scalar*super().__new__(cls, *multifields)
else:
return scalar
def __call__(self, *fields):
"""Apply on a list of fields.
If the number of input fields supplied is not equal to the order of
the tensor product field, the list of arguments is padded with ``None``'s.
The list of arguments is divided in sublists depending on the order of
the forms inside the tensor product. The sublists are provided as
arguments to these forms and the resulting expressions are given to the
constructor of ``TensorProduct``.
"""
tot_order = covariant_order(self) + contravariant_order(self)
tot_args = len(fields)
if tot_args != tot_order:
fields = list(fields) + [None]*(tot_order - tot_args)
orders = [covariant_order(f) + contravariant_order(f) for f in self._args]
indices = [sum(orders[:i + 1]) for i in range(len(orders) - 1)]
fields = [fields[i:j] for i, j in zip([0] + indices, indices + [None])]
multipliers = [t[0].rcall(*t[1]) for t in zip(self._args, fields)]
return TensorProduct(*multipliers)
class WedgeProduct(TensorProduct):
"""Wedge product of forms.
Explanation
===========
In the context of integration only completely antisymmetric forms make
sense. The wedge product permits the creation of such forms.
Examples
========
>>> from sympy.diffgeom.rn import R2_r
>>> from sympy.diffgeom import WedgeProduct
>>> fx, fy = R2_r.base_scalars()
>>> e_x, e_y = R2_r.base_vectors()
>>> dx, dy = R2_r.base_oneforms()
>>> WedgeProduct(dx, dy)(e_x, e_y)
1
>>> WedgeProduct(dx, dy)(e_y, e_x)
-1
>>> WedgeProduct(dx, fx*dy)(fx*e_x, e_y)
x**2
>>> WedgeProduct(e_x, e_y)(fy, None)
-e_x
You can nest wedge products.
>>> wp1 = WedgeProduct(dx, dy)
>>> WedgeProduct(wp1, dx)(e_x, e_y, e_x)
0
"""
# TODO the calculation of signatures is slow
# TODO you do not need all these permutations (neither the prefactor)
def __call__(self, *fields):
"""Apply on a list of vector_fields.
The expression is rewritten internally in terms of tensor products and evaluated."""
orders = (covariant_order(e) + contravariant_order(e) for e in self.args)
mul = 1/Mul(*(factorial(o) for o in orders))
perms = permutations(fields)
perms_par = (Permutation(
p).signature() for p in permutations(range(len(fields))))
tensor_prod = TensorProduct(*self.args)
return mul*Add(*[tensor_prod(*p[0])*p[1] for p in zip(perms, perms_par)])
class LieDerivative(Expr):
"""Lie derivative with respect to a vector field.
Explanation
===========
The transport operator that defines the Lie derivative is the pushforward of
the field to be derived along the integral curve of the field with respect
to which one derives.
Examples
========
>>> from sympy.diffgeom.rn import R2_r, R2_p
>>> from sympy.diffgeom import (LieDerivative, TensorProduct)
>>> fx, fy = R2_r.base_scalars()
>>> e_x, e_y = R2_r.base_vectors()
>>> e_rho, e_theta = R2_p.base_vectors()
>>> dx, dy = R2_r.base_oneforms()
>>> LieDerivative(e_x, fy)
0
>>> LieDerivative(e_x, fx)
1
>>> LieDerivative(e_x, e_x)
0
The Lie derivative of a tensor field by another tensor field is equal to
their commutator:
>>> LieDerivative(e_x, e_rho)
Commutator(e_x, e_rho)
>>> LieDerivative(e_x + e_y, fx)
1
>>> tp = TensorProduct(dx, dy)
>>> LieDerivative(e_x, tp)
LieDerivative(e_x, TensorProduct(dx, dy))
>>> LieDerivative(e_x, tp)
LieDerivative(e_x, TensorProduct(dx, dy))
"""
def __new__(cls, v_field, expr):
expr_form_ord = covariant_order(expr)
if contravariant_order(v_field) != 1 or covariant_order(v_field):
raise ValueError('Lie derivatives are defined only with respect to'
' vector fields. The supplied argument was not a '
'vector field.')
if expr_form_ord > 0:
obj = super().__new__(cls, v_field, expr)
# deprecated assignments
obj._v_field = v_field
obj._expr = expr
return obj
if expr.atoms(BaseVectorField):
return Commutator(v_field, expr)
else:
return v_field.rcall(expr)
@property
def v_field(self):
return self.args[0]
@property
def expr(self):
return self.args[1]
def __call__(self, *args):
v = self.v_field
expr = self.expr
lead_term = v(expr(*args))
rest = Add(*[Mul(*args[:i] + (Commutator(v, args[i]),) + args[i + 1:])
for i in range(len(args))])
return lead_term - rest
class BaseCovarDerivativeOp(Expr):
"""Covariant derivative operator with respect to a base vector.
Examples
========
>>> from sympy.diffgeom.rn import R2_r
>>> from sympy.diffgeom import BaseCovarDerivativeOp
>>> from sympy.diffgeom import metric_to_Christoffel_2nd, TensorProduct
>>> TP = TensorProduct
>>> fx, fy = R2_r.base_scalars()
>>> e_x, e_y = R2_r.base_vectors()
>>> dx, dy = R2_r.base_oneforms()
>>> ch = metric_to_Christoffel_2nd(TP(dx, dx) + TP(dy, dy))
>>> ch
[[[0, 0], [0, 0]], [[0, 0], [0, 0]]]
>>> cvd = BaseCovarDerivativeOp(R2_r, 0, ch)
>>> cvd(fx)
1
>>> cvd(fx*e_x)
e_x
"""
def __new__(cls, coord_sys, index, christoffel):
index = _sympify(index)
christoffel = ImmutableDenseNDimArray(christoffel)
obj = super().__new__(cls, coord_sys, index, christoffel)
# deprecated assignments
obj._coord_sys = coord_sys
obj._index = index
obj._christoffel = christoffel
return obj
@property
def coord_sys(self):
return self.args[0]
@property
def index(self):
return self.args[1]
@property
def christoffel(self):
return self.args[2]
def __call__(self, field):
"""Apply on a scalar field.
The action of a vector field on a scalar field is a directional
differentiation.
If the argument is not a scalar field the behaviour is undefined.
"""
if covariant_order(field) != 0:
raise NotImplementedError()
field = vectors_in_basis(field, self._coord_sys)
wrt_vector = self._coord_sys.base_vector(self._index)
wrt_scalar = self._coord_sys.coord_function(self._index)
vectors = list(field.atoms(BaseVectorField))
# First step: replace all vectors with something susceptible to
# derivation and do the derivation
# TODO: you need a real dummy function for the next line
d_funcs = [Function('_#_%s' % i)(wrt_scalar) for i,
b in enumerate(vectors)]
d_result = field.subs(list(zip(vectors, d_funcs)))
d_result = wrt_vector(d_result)
# Second step: backsubstitute the vectors in
d_result = d_result.subs(list(zip(d_funcs, vectors)))
# Third step: evaluate the derivatives of the vectors
derivs = []
for v in vectors:
d = Add(*[(self._christoffel[k, wrt_vector._index, v._index]
*v._coord_sys.base_vector(k))
for k in range(v._coord_sys.dim)])
derivs.append(d)
to_subs = [wrt_vector(d) for d in d_funcs]
# XXX: This substitution can fail when there are Dummy symbols and the
# cache is disabled: https://github.com/sympy/sympy/issues/17794
result = d_result.subs(list(zip(to_subs, derivs)))
# Remove the dummies
result = result.subs(list(zip(d_funcs, vectors)))
return result.doit()
class CovarDerivativeOp(Expr):
"""Covariant derivative operator.
Examples
========
>>> from sympy.diffgeom.rn import R2_r
>>> from sympy.diffgeom import CovarDerivativeOp
>>> from sympy.diffgeom import metric_to_Christoffel_2nd, TensorProduct
>>> TP = TensorProduct
>>> fx, fy = R2_r.base_scalars()
>>> e_x, e_y = R2_r.base_vectors()
>>> dx, dy = R2_r.base_oneforms()
>>> ch = metric_to_Christoffel_2nd(TP(dx, dx) + TP(dy, dy))
>>> ch
[[[0, 0], [0, 0]], [[0, 0], [0, 0]]]
>>> cvd = CovarDerivativeOp(fx*e_x, ch)
>>> cvd(fx)
x
>>> cvd(fx*e_x)
x*e_x
"""
def __new__(cls, wrt, christoffel):
if len({v._coord_sys for v in wrt.atoms(BaseVectorField)}) > 1:
raise NotImplementedError()
if contravariant_order(wrt) != 1 or covariant_order(wrt):
raise ValueError('Covariant derivatives are defined only with '
'respect to vector fields. The supplied argument '
'was not a vector field.')
christoffel = ImmutableDenseNDimArray(christoffel)
obj = super().__new__(cls, wrt, christoffel)
# deprecated assignments
obj._wrt = wrt
obj._christoffel = christoffel
return obj
@property
def wrt(self):
return self.args[0]
@property
def christoffel(self):
return self.args[1]
def __call__(self, field):
vectors = list(self._wrt.atoms(BaseVectorField))
base_ops = [BaseCovarDerivativeOp(v._coord_sys, v._index, self._christoffel)
for v in vectors]
return self._wrt.subs(list(zip(vectors, base_ops))).rcall(field)
###############################################################################
# Integral curves on vector fields
###############################################################################
def intcurve_series(vector_field, param, start_point, n=6, coord_sys=None, coeffs=False):
r"""Return the series expansion for an integral curve of the field.
Explanation
===========
Integral curve is a function `\gamma` taking a parameter in `R` to a point
in the manifold. It verifies the equation:
`V(f)\big(\gamma(t)\big) = \frac{d}{dt}f\big(\gamma(t)\big)`
where the given ``vector_field`` is denoted as `V`. This holds for any
value `t` for the parameter and any scalar field `f`.
This equation can also be decomposed of a basis of coordinate functions
`V(f_i)\big(\gamma(t)\big) = \frac{d}{dt}f_i\big(\gamma(t)\big) \quad \forall i`
This function returns a series expansion of `\gamma(t)` in terms of the
coordinate system ``coord_sys``. The equations and expansions are necessarily
done in coordinate-system-dependent way as there is no other way to
represent movement between points on the manifold (i.e. there is no such
thing as a difference of points for a general manifold).
Parameters
==========
vector_field
the vector field for which an integral curve will be given
param
the argument of the function `\gamma` from R to the curve
start_point
the point which corresponds to `\gamma(0)`
n
the order to which to expand
coord_sys
the coordinate system in which to expand
coeffs (default False) - if True return a list of elements of the expansion
Examples
========
Use the predefined R2 manifold:
>>> from sympy.abc import t, x, y
>>> from sympy.diffgeom.rn import R2_p, R2_r
>>> from sympy.diffgeom import intcurve_series
Specify a starting point and a vector field:
>>> start_point = R2_r.point([x, y])
>>> vector_field = R2_r.e_x
Calculate the series:
>>> intcurve_series(vector_field, t, start_point, n=3)
Matrix([
[t + x],
[ y]])
Or get the elements of the expansion in a list:
>>> series = intcurve_series(vector_field, t, start_point, n=3, coeffs=True)
>>> series[0]
Matrix([
[x],
[y]])
>>> series[1]
Matrix([
[t],
[0]])
>>> series[2]
Matrix([
[0],
[0]])
The series in the polar coordinate system:
>>> series = intcurve_series(vector_field, t, start_point,
... n=3, coord_sys=R2_p, coeffs=True)
>>> series[0]
Matrix([
[sqrt(x**2 + y**2)],
[ atan2(y, x)]])
>>> series[1]
Matrix([
[t*x/sqrt(x**2 + y**2)],
[ -t*y/(x**2 + y**2)]])
>>> series[2]
Matrix([
[t**2*(-x**2/(x**2 + y**2)**(3/2) + 1/sqrt(x**2 + y**2))/2],
[ t**2*x*y/(x**2 + y**2)**2]])
See Also
========
intcurve_diffequ
"""
if contravariant_order(vector_field) != 1 or covariant_order(vector_field):
raise ValueError('The supplied field was not a vector field.')
def iter_vfield(scalar_field, i):
"""Return ``vector_field`` called `i` times on ``scalar_field``."""
return reduce(lambda s, v: v.rcall(s), [vector_field, ]*i, scalar_field)
def taylor_terms_per_coord(coord_function):
"""Return the series for one of the coordinates."""
return [param**i*iter_vfield(coord_function, i).rcall(start_point)/factorial(i)
for i in range(n)]
coord_sys = coord_sys if coord_sys else start_point._coord_sys
coord_functions = coord_sys.coord_functions()
taylor_terms = [taylor_terms_per_coord(f) for f in coord_functions]
if coeffs:
return [Matrix(t) for t in zip(*taylor_terms)]
else:
return Matrix([sum(c) for c in taylor_terms])
def intcurve_diffequ(vector_field, param, start_point, coord_sys=None):
r"""Return the differential equation for an integral curve of the field.
Explanation
===========
Integral curve is a function `\gamma` taking a parameter in `R` to a point
in the manifold. It verifies the equation:
`V(f)\big(\gamma(t)\big) = \frac{d}{dt}f\big(\gamma(t)\big)`
where the given ``vector_field`` is denoted as `V`. This holds for any
value `t` for the parameter and any scalar field `f`.
This function returns the differential equation of `\gamma(t)` in terms of the
coordinate system ``coord_sys``. The equations and expansions are necessarily
done in coordinate-system-dependent way as there is no other way to
represent movement between points on the manifold (i.e. there is no such
thing as a difference of points for a general manifold).
Parameters
==========
vector_field
the vector field for which an integral curve will be given
param
the argument of the function `\gamma` from R to the curve
start_point
the point which corresponds to `\gamma(0)`
coord_sys
the coordinate system in which to give the equations
Returns
=======
a tuple of (equations, initial conditions)
Examples
========
Use the predefined R2 manifold:
>>> from sympy.abc import t
>>> from sympy.diffgeom.rn import R2, R2_p, R2_r
>>> from sympy.diffgeom import intcurve_diffequ
Specify a starting point and a vector field:
>>> start_point = R2_r.point([0, 1])
>>> vector_field = -R2.y*R2.e_x + R2.x*R2.e_y
Get the equation:
>>> equations, init_cond = intcurve_diffequ(vector_field, t, start_point)
>>> equations
[f_1(t) + Derivative(f_0(t), t), -f_0(t) + Derivative(f_1(t), t)]
>>> init_cond
[f_0(0), f_1(0) - 1]
The series in the polar coordinate system:
>>> equations, init_cond = intcurve_diffequ(vector_field, t, start_point, R2_p)
>>> equations
[Derivative(f_0(t), t), Derivative(f_1(t), t) - 1]
>>> init_cond
[f_0(0) - 1, f_1(0) - pi/2]
See Also
========
intcurve_series
"""
if contravariant_order(vector_field) != 1 or covariant_order(vector_field):
raise ValueError('The supplied field was not a vector field.')
coord_sys = coord_sys if coord_sys else start_point._coord_sys
gammas = [Function('f_%d' % i)(param) for i in range(
start_point._coord_sys.dim)]
arbitrary_p = Point(coord_sys, gammas)
coord_functions = coord_sys.coord_functions()
equations = [simplify(diff(cf.rcall(arbitrary_p), param) - vector_field.rcall(cf).rcall(arbitrary_p))
for cf in coord_functions]
init_cond = [simplify(cf.rcall(arbitrary_p).subs(param, 0) - cf.rcall(start_point))
for cf in coord_functions]
return equations, init_cond
###############################################################################
# Helpers
###############################################################################
def dummyfy(args, exprs):
# TODO Is this a good idea?
d_args = Matrix([s.as_dummy() for s in args])
reps = dict(zip(args, d_args))
d_exprs = Matrix([_sympify(expr).subs(reps) for expr in exprs])
return d_args, d_exprs
###############################################################################
# Helpers
###############################################################################
def contravariant_order(expr, _strict=False):
"""Return the contravariant order of an expression.
Examples
========
>>> from sympy.diffgeom import contravariant_order
>>> from sympy.diffgeom.rn import R2
>>> from sympy.abc import a
>>> contravariant_order(a)
0
>>> contravariant_order(a*R2.x + 2)
0
>>> contravariant_order(a*R2.x*R2.e_y + R2.e_x)
1
"""
# TODO move some of this to class methods.
# TODO rewrite using the .as_blah_blah methods
if isinstance(expr, Add):
orders = [contravariant_order(e) for e in expr.args]
if len(set(orders)) != 1:
raise ValueError('Misformed expression containing contravariant fields of varying order.')
return orders[0]
elif isinstance(expr, Mul):
orders = [contravariant_order(e) for e in expr.args]
not_zero = [o for o in orders if o != 0]
if len(not_zero) > 1:
raise ValueError('Misformed expression containing multiplication between vectors.')
return 0 if not not_zero else not_zero[0]
elif isinstance(expr, Pow):
if covariant_order(expr.base) or covariant_order(expr.exp):
raise ValueError(
'Misformed expression containing a power of a vector.')
return 0
elif isinstance(expr, BaseVectorField):
return 1
elif isinstance(expr, TensorProduct):
return sum(contravariant_order(a) for a in expr.args)
elif not _strict or expr.atoms(BaseScalarField):
return 0
else: # If it does not contain anything related to the diffgeom module and it is _strict
return -1
def covariant_order(expr, _strict=False):
"""Return the covariant order of an expression.
Examples
========
>>> from sympy.diffgeom import covariant_order
>>> from sympy.diffgeom.rn import R2
>>> from sympy.abc import a
>>> covariant_order(a)
0
>>> covariant_order(a*R2.x + 2)
0
>>> covariant_order(a*R2.x*R2.dy + R2.dx)
1
"""
# TODO move some of this to class methods.
# TODO rewrite using the .as_blah_blah methods
if isinstance(expr, Add):
orders = [covariant_order(e) for e in expr.args]
if len(set(orders)) != 1:
raise ValueError('Misformed expression containing form fields of varying order.')
return orders[0]
elif isinstance(expr, Mul):
orders = [covariant_order(e) for e in expr.args]
not_zero = [o for o in orders if o != 0]
if len(not_zero) > 1:
raise ValueError('Misformed expression containing multiplication between forms.')
return 0 if not not_zero else not_zero[0]
elif isinstance(expr, Pow):
if covariant_order(expr.base) or covariant_order(expr.exp):
raise ValueError(
'Misformed expression containing a power of a form.')
return 0
elif isinstance(expr, Differential):
return covariant_order(*expr.args) + 1
elif isinstance(expr, TensorProduct):
return sum(covariant_order(a) for a in expr.args)
elif not _strict or expr.atoms(BaseScalarField):
return 0
else: # If it does not contain anything related to the diffgeom module and it is _strict
return -1
###############################################################################
# Coordinate transformation functions
###############################################################################
def vectors_in_basis(expr, to_sys):
"""Transform all base vectors in base vectors of a specified coord basis.
While the new base vectors are in the new coordinate system basis, any
coefficients are kept in the old system.
Examples
========
>>> from sympy.diffgeom import vectors_in_basis
>>> from sympy.diffgeom.rn import R2_r, R2_p
>>> vectors_in_basis(R2_r.e_x, R2_p)
-y*e_theta/(x**2 + y**2) + x*e_rho/sqrt(x**2 + y**2)
>>> vectors_in_basis(R2_p.e_r, R2_r)
sin(theta)*e_y + cos(theta)*e_x
"""
vectors = list(expr.atoms(BaseVectorField))
new_vectors = []
for v in vectors:
cs = v._coord_sys
jac = cs.jacobian(to_sys, cs.coord_functions())
new = (jac.T*Matrix(to_sys.base_vectors()))[v._index]
new_vectors.append(new)
return expr.subs(list(zip(vectors, new_vectors)))
###############################################################################
# Coordinate-dependent functions
###############################################################################
def twoform_to_matrix(expr):
"""Return the matrix representing the twoform.
For the twoform `w` return the matrix `M` such that `M[i,j]=w(e_i, e_j)`,
where `e_i` is the i-th base vector field for the coordinate system in
which the expression of `w` is given.
Examples
========
>>> from sympy.diffgeom.rn import R2
>>> from sympy.diffgeom import twoform_to_matrix, TensorProduct
>>> TP = TensorProduct
>>> twoform_to_matrix(TP(R2.dx, R2.dx) + TP(R2.dy, R2.dy))
Matrix([
[1, 0],
[0, 1]])
>>> twoform_to_matrix(R2.x*TP(R2.dx, R2.dx) + TP(R2.dy, R2.dy))
Matrix([
[x, 0],
[0, 1]])
>>> twoform_to_matrix(TP(R2.dx, R2.dx) + TP(R2.dy, R2.dy) - TP(R2.dx, R2.dy)/2)
Matrix([
[ 1, 0],
[-1/2, 1]])
"""
if covariant_order(expr) != 2 or contravariant_order(expr):
raise ValueError('The input expression is not a two-form.')
coord_sys = _find_coords(expr)
if len(coord_sys) != 1:
raise ValueError('The input expression concerns more than one '
'coordinate systems, hence there is no unambiguous '
'way to choose a coordinate system for the matrix.')
coord_sys = coord_sys.pop()
vectors = coord_sys.base_vectors()
expr = expr.expand()
matrix_content = [[expr.rcall(v1, v2) for v1 in vectors]
for v2 in vectors]
return Matrix(matrix_content)
def metric_to_Christoffel_1st(expr):
"""Return the nested list of Christoffel symbols for the given metric.
This returns the Christoffel symbol of first kind that represents the
Levi-Civita connection for the given metric.
Examples
========
>>> from sympy.diffgeom.rn import R2
>>> from sympy.diffgeom import metric_to_Christoffel_1st, TensorProduct
>>> TP = TensorProduct
>>> metric_to_Christoffel_1st(TP(R2.dx, R2.dx) + TP(R2.dy, R2.dy))
[[[0, 0], [0, 0]], [[0, 0], [0, 0]]]
>>> metric_to_Christoffel_1st(R2.x*TP(R2.dx, R2.dx) + TP(R2.dy, R2.dy))
[[[1/2, 0], [0, 0]], [[0, 0], [0, 0]]]
"""
matrix = twoform_to_matrix(expr)
if not matrix.is_symmetric():
raise ValueError(
'The two-form representing the metric is not symmetric.')
coord_sys = _find_coords(expr).pop()
deriv_matrices = [matrix.applyfunc(d) for d in coord_sys.base_vectors()]
indices = list(range(coord_sys.dim))
christoffel = [[[(deriv_matrices[k][i, j] + deriv_matrices[j][i, k] - deriv_matrices[i][j, k])/2
for k in indices]
for j in indices]
for i in indices]
return ImmutableDenseNDimArray(christoffel)
def metric_to_Christoffel_2nd(expr):
"""Return the nested list of Christoffel symbols for the given metric.
This returns the Christoffel symbol of second kind that represents the
Levi-Civita connection for the given metric.
Examples
========
>>> from sympy.diffgeom.rn import R2
>>> from sympy.diffgeom import metric_to_Christoffel_2nd, TensorProduct
>>> TP = TensorProduct
>>> metric_to_Christoffel_2nd(TP(R2.dx, R2.dx) + TP(R2.dy, R2.dy))
[[[0, 0], [0, 0]], [[0, 0], [0, 0]]]
>>> metric_to_Christoffel_2nd(R2.x*TP(R2.dx, R2.dx) + TP(R2.dy, R2.dy))
[[[1/(2*x), 0], [0, 0]], [[0, 0], [0, 0]]]
"""
ch_1st = metric_to_Christoffel_1st(expr)
coord_sys = _find_coords(expr).pop()
indices = list(range(coord_sys.dim))
# XXX workaround, inverting a matrix does not work if it contains non
# symbols
#matrix = twoform_to_matrix(expr).inv()
matrix = twoform_to_matrix(expr)
s_fields = set()
for e in matrix:
s_fields.update(e.atoms(BaseScalarField))
s_fields = list(s_fields)
dums = coord_sys.symbols
matrix = matrix.subs(list(zip(s_fields, dums))).inv().subs(list(zip(dums, s_fields)))
# XXX end of workaround
christoffel = [[[Add(*[matrix[i, l]*ch_1st[l, j, k] for l in indices])
for k in indices]
for j in indices]
for i in indices]
return ImmutableDenseNDimArray(christoffel)
def metric_to_Riemann_components(expr):
"""Return the components of the Riemann tensor expressed in a given basis.
Given a metric it calculates the components of the Riemann tensor in the
canonical basis of the coordinate system in which the metric expression is
given.
Examples
========
>>> from sympy import exp
>>> from sympy.diffgeom.rn import R2
>>> from sympy.diffgeom import metric_to_Riemann_components, TensorProduct
>>> TP = TensorProduct
>>> metric_to_Riemann_components(TP(R2.dx, R2.dx) + TP(R2.dy, R2.dy))
[[[[0, 0], [0, 0]], [[0, 0], [0, 0]]], [[[0, 0], [0, 0]], [[0, 0], [0, 0]]]]
>>> non_trivial_metric = exp(2*R2.r)*TP(R2.dr, R2.dr) + \
R2.r**2*TP(R2.dtheta, R2.dtheta)
>>> non_trivial_metric
exp(2*rho)*TensorProduct(drho, drho) + rho**2*TensorProduct(dtheta, dtheta)
>>> riemann = metric_to_Riemann_components(non_trivial_metric)
>>> riemann[0, :, :, :]
[[[0, 0], [0, 0]], [[0, exp(-2*rho)*rho], [-exp(-2*rho)*rho, 0]]]
>>> riemann[1, :, :, :]
[[[0, -1/rho], [1/rho, 0]], [[0, 0], [0, 0]]]
"""
ch_2nd = metric_to_Christoffel_2nd(expr)
coord_sys = _find_coords(expr).pop()
indices = list(range(coord_sys.dim))
deriv_ch = [[[[d(ch_2nd[i, j, k])
for d in coord_sys.base_vectors()]
for k in indices]
for j in indices]
for i in indices]
riemann_a = [[[[deriv_ch[rho][sig][nu][mu] - deriv_ch[rho][sig][mu][nu]
for nu in indices]
for mu in indices]
for sig in indices]
for rho in indices]
riemann_b = [[[[Add(*[ch_2nd[rho, l, mu]*ch_2nd[l, sig, nu] - ch_2nd[rho, l, nu]*ch_2nd[l, sig, mu] for l in indices])
for nu in indices]
for mu in indices]
for sig in indices]
for rho in indices]
riemann = [[[[riemann_a[rho][sig][mu][nu] + riemann_b[rho][sig][mu][nu]
for nu in indices]
for mu in indices]
for sig in indices]
for rho in indices]
return ImmutableDenseNDimArray(riemann)
def metric_to_Ricci_components(expr):
"""Return the components of the Ricci tensor expressed in a given basis.
Given a metric it calculates the components of the Ricci tensor in the
canonical basis of the coordinate system in which the metric expression is
given.
Examples
========
>>> from sympy import exp
>>> from sympy.diffgeom.rn import R2
>>> from sympy.diffgeom import metric_to_Ricci_components, TensorProduct
>>> TP = TensorProduct
>>> metric_to_Ricci_components(TP(R2.dx, R2.dx) + TP(R2.dy, R2.dy))
[[0, 0], [0, 0]]
>>> non_trivial_metric = exp(2*R2.r)*TP(R2.dr, R2.dr) + \
R2.r**2*TP(R2.dtheta, R2.dtheta)
>>> non_trivial_metric
exp(2*rho)*TensorProduct(drho, drho) + rho**2*TensorProduct(dtheta, dtheta)
>>> metric_to_Ricci_components(non_trivial_metric)
[[1/rho, 0], [0, exp(-2*rho)*rho]]
"""
riemann = metric_to_Riemann_components(expr)
coord_sys = _find_coords(expr).pop()
indices = list(range(coord_sys.dim))
ricci = [[Add(*[riemann[k, i, k, j] for k in indices])
for j in indices]
for i in indices]
return ImmutableDenseNDimArray(ricci)
###############################################################################
# Classes for deprecation
###############################################################################
class _deprecated_container:
# This class gives deprecation warning.
# When deprecated features are completely deleted, this should be removed as well.
# See https://github.com/sympy/sympy/pull/19368
def __init__(self, message, data):
super().__init__(data)
self.message = message
def warn(self):
sympy_deprecation_warning(
self.message,
deprecated_since_version="1.7",
active_deprecations_target="deprecated-diffgeom-mutable",
stacklevel=4
)
def __iter__(self):
self.warn()
return super().__iter__()
def __getitem__(self, key):
self.warn()
return super().__getitem__(key)
def __contains__(self, key):
self.warn()
return super().__contains__(key)
class _deprecated_list(_deprecated_container, list):
pass
class _deprecated_dict(_deprecated_container, dict):
pass
# Import at end to avoid cyclic imports
from sympy.simplify.simplify import simplify
PK ]ZZZ�7\�x x sympy/diffgeom/rn.py"""Predefined R^n manifolds together with common coord. systems.
Coordinate systems are predefined as well as the transformation laws between
them.
Coordinate functions can be accessed as attributes of the manifold (eg `R2.x`),
as attributes of the coordinate systems (eg `R2_r.x` and `R2_p.theta`), or by
using the usual `coord_sys.coord_function(index, name)` interface.
"""
from typing import Any
import warnings
from sympy.core.symbol import (Dummy, symbols)
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.elementary.trigonometric import (acos, atan2, cos, sin)
from .diffgeom import Manifold, Patch, CoordSystem
__all__ = [
'R2', 'R2_origin', 'relations_2d', 'R2_r', 'R2_p',
'R3', 'R3_origin', 'relations_3d', 'R3_r', 'R3_c', 'R3_s'
]
###############################################################################
# R2
###############################################################################
R2: Any = Manifold('R^2', 2)
R2_origin: Any = Patch('origin', R2)
x, y = symbols('x y', real=True)
r, theta = symbols('rho theta', nonnegative=True)
relations_2d = {
('rectangular', 'polar'): [(x, y), (sqrt(x**2 + y**2), atan2(y, x))],
('polar', 'rectangular'): [(r, theta), (r*cos(theta), r*sin(theta))],
}
R2_r: Any = CoordSystem('rectangular', R2_origin, (x, y), relations_2d)
R2_p: Any = CoordSystem('polar', R2_origin, (r, theta), relations_2d)
# support deprecated feature
with warnings.catch_warnings():
warnings.simplefilter("ignore")
x, y, r, theta = symbols('x y r theta', cls=Dummy)
R2_r.connect_to(R2_p, [x, y],
[sqrt(x**2 + y**2), atan2(y, x)],
inverse=False, fill_in_gaps=False)
R2_p.connect_to(R2_r, [r, theta],
[r*cos(theta), r*sin(theta)],
inverse=False, fill_in_gaps=False)
# Defining the basis coordinate functions and adding shortcuts for them to the
# manifold and the patch.
R2.x, R2.y = R2_origin.x, R2_origin.y = R2_r.x, R2_r.y = R2_r.coord_functions()
R2.r, R2.theta = R2_origin.r, R2_origin.theta = R2_p.r, R2_p.theta = R2_p.coord_functions()
# Defining the basis vector fields and adding shortcuts for them to the
# manifold and the patch.
R2.e_x, R2.e_y = R2_origin.e_x, R2_origin.e_y = R2_r.e_x, R2_r.e_y = R2_r.base_vectors()
R2.e_r, R2.e_theta = R2_origin.e_r, R2_origin.e_theta = R2_p.e_r, R2_p.e_theta = R2_p.base_vectors()
# Defining the basis oneform fields and adding shortcuts for them to the
# manifold and the patch.
R2.dx, R2.dy = R2_origin.dx, R2_origin.dy = R2_r.dx, R2_r.dy = R2_r.base_oneforms()
R2.dr, R2.dtheta = R2_origin.dr, R2_origin.dtheta = R2_p.dr, R2_p.dtheta = R2_p.base_oneforms()
###############################################################################
# R3
###############################################################################
R3: Any = Manifold('R^3', 3)
R3_origin: Any = Patch('origin', R3)
x, y, z = symbols('x y z', real=True)
rho, psi, r, theta, phi = symbols('rho psi r theta phi', nonnegative=True)
relations_3d = {
('rectangular', 'cylindrical'): [(x, y, z),
(sqrt(x**2 + y**2), atan2(y, x), z)],
('cylindrical', 'rectangular'): [(rho, psi, z),
(rho*cos(psi), rho*sin(psi), z)],
('rectangular', 'spherical'): [(x, y, z),
(sqrt(x**2 + y**2 + z**2),
acos(z/sqrt(x**2 + y**2 + z**2)),
atan2(y, x))],
('spherical', 'rectangular'): [(r, theta, phi),
(r*sin(theta)*cos(phi),
r*sin(theta)*sin(phi),
r*cos(theta))],
('cylindrical', 'spherical'): [(rho, psi, z),
(sqrt(rho**2 + z**2),
acos(z/sqrt(rho**2 + z**2)),
psi)],
('spherical', 'cylindrical'): [(r, theta, phi),
(r*sin(theta), phi, r*cos(theta))],
}
R3_r: Any = CoordSystem('rectangular', R3_origin, (x, y, z), relations_3d)
R3_c: Any = CoordSystem('cylindrical', R3_origin, (rho, psi, z), relations_3d)
R3_s: Any = CoordSystem('spherical', R3_origin, (r, theta, phi), relations_3d)
# support deprecated feature
with warnings.catch_warnings():
warnings.simplefilter("ignore")
x, y, z, rho, psi, r, theta, phi = symbols('x y z rho psi r theta phi', cls=Dummy)
R3_r.connect_to(R3_c, [x, y, z],
[sqrt(x**2 + y**2), atan2(y, x), z],
inverse=False, fill_in_gaps=False)
R3_c.connect_to(R3_r, [rho, psi, z],
[rho*cos(psi), rho*sin(psi), z],
inverse=False, fill_in_gaps=False)
## rectangular <-> spherical
R3_r.connect_to(R3_s, [x, y, z],
[sqrt(x**2 + y**2 + z**2), acos(z/
sqrt(x**2 + y**2 + z**2)), atan2(y, x)],
inverse=False, fill_in_gaps=False)
R3_s.connect_to(R3_r, [r, theta, phi],
[r*sin(theta)*cos(phi), r*sin(
theta)*sin(phi), r*cos(theta)],
inverse=False, fill_in_gaps=False)
## cylindrical <-> spherical
R3_c.connect_to(R3_s, [rho, psi, z],
[sqrt(rho**2 + z**2), acos(z/sqrt(rho**2 + z**2)), psi],
inverse=False, fill_in_gaps=False)
R3_s.connect_to(R3_c, [r, theta, phi],
[r*sin(theta), phi, r*cos(theta)],
inverse=False, fill_in_gaps=False)
# Defining the basis coordinate functions.
R3_r.x, R3_r.y, R3_r.z = R3_r.coord_functions()
R3_c.rho, R3_c.psi, R3_c.z = R3_c.coord_functions()
R3_s.r, R3_s.theta, R3_s.phi = R3_s.coord_functions()
# Defining the basis vector fields.
R3_r.e_x, R3_r.e_y, R3_r.e_z = R3_r.base_vectors()
R3_c.e_rho, R3_c.e_psi, R3_c.e_z = R3_c.base_vectors()
R3_s.e_r, R3_s.e_theta, R3_s.e_phi = R3_s.base_vectors()
# Defining the basis oneform fields.
R3_r.dx, R3_r.dy, R3_r.dz = R3_r.base_oneforms()
R3_c.drho, R3_c.dpsi, R3_c.dz = R3_c.base_oneforms()
R3_s.dr, R3_s.dtheta, R3_s.dphi = R3_s.base_oneforms()
PK ]ZZZ�g� sympy/discrete/__init__.py"""This module contains functions which operate on discrete sequences.
Transforms - ``fft``, ``ifft``, ``ntt``, ``intt``, ``fwht``, ``ifwht``,
``mobius_transform``, ``inverse_mobius_transform``
Convolutions - ``convolution``, ``convolution_fft``, ``convolution_ntt``,
``convolution_fwht``, ``convolution_subset``,
``covering_product``, ``intersecting_product``
"""
from .transforms import (fft, ifft, ntt, intt, fwht, ifwht,
mobius_transform, inverse_mobius_transform)
from .convolutions import convolution, covering_product, intersecting_product
__all__ = [
'fft', 'ifft', 'ntt', 'intt', 'fwht', 'ifwht', 'mobius_transform',
'inverse_mobius_transform',
'convolution', 'covering_product', 'intersecting_product',
]
PK ]ZZZ��m?�G �G sympy/discrete/convolutions.py"""
Convolution (using **FFT**, **NTT**, **FWHT**), Subset Convolution,
Covering Product, Intersecting Product
"""
from sympy.core import S, sympify, Rational
from sympy.core.function import expand_mul
from sympy.discrete.transforms import (
fft, ifft, ntt, intt, fwht, ifwht,
mobius_transform, inverse_mobius_transform)
from sympy.external.gmpy import MPZ, lcm
from sympy.utilities.iterables import iterable
from sympy.utilities.misc import as_int
def convolution(a, b, cycle=0, dps=None, prime=None, dyadic=None, subset=None):
"""
Performs convolution by determining the type of desired
convolution using hints.
Exactly one of ``dps``, ``prime``, ``dyadic``, ``subset`` arguments
should be specified explicitly for identifying the type of convolution,
and the argument ``cycle`` can be specified optionally.
For the default arguments, linear convolution is performed using **FFT**.
Parameters
==========
a, b : iterables
The sequences for which convolution is performed.
cycle : Integer
Specifies the length for doing cyclic convolution.
dps : Integer
Specifies the number of decimal digits for precision for
performing **FFT** on the sequence.
prime : Integer
Prime modulus of the form `(m 2^k + 1)` to be used for
performing **NTT** on the sequence.
dyadic : bool
Identifies the convolution type as dyadic (*bitwise-XOR*)
convolution, which is performed using **FWHT**.
subset : bool
Identifies the convolution type as subset convolution.
Examples
========
>>> from sympy import convolution, symbols, S, I
>>> u, v, w, x, y, z = symbols('u v w x y z')
>>> convolution([1 + 2*I, 4 + 3*I], [S(5)/4, 6], dps=3)
[1.25 + 2.5*I, 11.0 + 15.8*I, 24.0 + 18.0*I]
>>> convolution([1, 2, 3], [4, 5, 6], cycle=3)
[31, 31, 28]
>>> convolution([111, 777], [888, 444], prime=19*2**10 + 1)
[1283, 19351, 14219]
>>> convolution([111, 777], [888, 444], prime=19*2**10 + 1, cycle=2)
[15502, 19351]
>>> convolution([u, v], [x, y, z], dyadic=True)
[u*x + v*y, u*y + v*x, u*z, v*z]
>>> convolution([u, v], [x, y, z], dyadic=True, cycle=2)
[u*x + u*z + v*y, u*y + v*x + v*z]
>>> convolution([u, v, w], [x, y, z], subset=True)
[u*x, u*y + v*x, u*z + w*x, v*z + w*y]
>>> convolution([u, v, w], [x, y, z], subset=True, cycle=3)
[u*x + v*z + w*y, u*y + v*x, u*z + w*x]
"""
c = as_int(cycle)
if c < 0:
raise ValueError("The length for cyclic convolution "
"must be non-negative")
dyadic = True if dyadic else None
subset = True if subset else None
if sum(x is not None for x in (prime, dps, dyadic, subset)) > 1:
raise TypeError("Ambiguity in determining the type of convolution")
if prime is not None:
ls = convolution_ntt(a, b, prime=prime)
return ls if not c else [sum(ls[i::c]) % prime for i in range(c)]
if dyadic:
ls = convolution_fwht(a, b)
elif subset:
ls = convolution_subset(a, b)
else:
def loop(a):
dens = []
for i in a:
if isinstance(i, Rational) and i.q - 1:
dens.append(i.q)
elif not isinstance(i, int):
return
if dens:
l = lcm(*dens)
return [i*l if type(i) is int else i.p*(l//i.q) for i in a], l
# no lcm of den to deal with
return a, 1
ls = None
da = loop(a)
if da is not None:
db = loop(b)
if db is not None:
(ia, ma), (ib, mb) = da, db
den = ma*mb
ls = convolution_int(ia, ib)
if den != 1:
ls = [Rational(i, den) for i in ls]
if ls is None:
ls = convolution_fft(a, b, dps)
return ls if not c else [sum(ls[i::c]) for i in range(c)]
#----------------------------------------------------------------------------#
# #
# Convolution for Complex domain #
# #
#----------------------------------------------------------------------------#
def convolution_fft(a, b, dps=None):
"""
Performs linear convolution using Fast Fourier Transform.
Parameters
==========
a, b : iterables
The sequences for which convolution is performed.
dps : Integer
Specifies the number of decimal digits for precision.
Examples
========
>>> from sympy import S, I
>>> from sympy.discrete.convolutions import convolution_fft
>>> convolution_fft([2, 3], [4, 5])
[8, 22, 15]
>>> convolution_fft([2, 5], [6, 7, 3])
[12, 44, 41, 15]
>>> convolution_fft([1 + 2*I, 4 + 3*I], [S(5)/4, 6])
[5/4 + 5*I/2, 11 + 63*I/4, 24 + 18*I]
References
==========
.. [1] https://en.wikipedia.org/wiki/Convolution_theorem
.. [2] https://en.wikipedia.org/wiki/Discrete_Fourier_transform_(general%29
"""
a, b = a[:], b[:]
n = m = len(a) + len(b) - 1 # convolution size
if n > 0 and n&(n - 1): # not a power of 2
n = 2**n.bit_length()
# padding with zeros
a += [S.Zero]*(n - len(a))
b += [S.Zero]*(n - len(b))
a, b = fft(a, dps), fft(b, dps)
a = [expand_mul(x*y) for x, y in zip(a, b)]
a = ifft(a, dps)[:m]
return a
#----------------------------------------------------------------------------#
# #
# Convolution for GF(p) #
# #
#----------------------------------------------------------------------------#
def convolution_ntt(a, b, prime):
"""
Performs linear convolution using Number Theoretic Transform.
Parameters
==========
a, b : iterables
The sequences for which convolution is performed.
prime : Integer
Prime modulus of the form `(m 2^k + 1)` to be used for performing
**NTT** on the sequence.
Examples
========
>>> from sympy.discrete.convolutions import convolution_ntt
>>> convolution_ntt([2, 3], [4, 5], prime=19*2**10 + 1)
[8, 22, 15]
>>> convolution_ntt([2, 5], [6, 7, 3], prime=19*2**10 + 1)
[12, 44, 41, 15]
>>> convolution_ntt([333, 555], [222, 666], prime=19*2**10 + 1)
[15555, 14219, 19404]
References
==========
.. [1] https://en.wikipedia.org/wiki/Convolution_theorem
.. [2] https://en.wikipedia.org/wiki/Discrete_Fourier_transform_(general%29
"""
a, b, p = a[:], b[:], as_int(prime)
n = m = len(a) + len(b) - 1 # convolution size
if n > 0 and n&(n - 1): # not a power of 2
n = 2**n.bit_length()
# padding with zeros
a += [0]*(n - len(a))
b += [0]*(n - len(b))
a, b = ntt(a, p), ntt(b, p)
a = [x*y % p for x, y in zip(a, b)]
a = intt(a, p)[:m]
return a
#----------------------------------------------------------------------------#
# #
# Convolution for 2**n-group #
# #
#----------------------------------------------------------------------------#
def convolution_fwht(a, b):
"""
Performs dyadic (*bitwise-XOR*) convolution using Fast Walsh Hadamard
Transform.
The convolution is automatically padded to the right with zeros, as the
*radix-2 FWHT* requires the number of sample points to be a power of 2.
Parameters
==========
a, b : iterables
The sequences for which convolution is performed.
Examples
========
>>> from sympy import symbols, S, I
>>> from sympy.discrete.convolutions import convolution_fwht
>>> u, v, x, y = symbols('u v x y')
>>> convolution_fwht([u, v], [x, y])
[u*x + v*y, u*y + v*x]
>>> convolution_fwht([2, 3], [4, 5])
[23, 22]
>>> convolution_fwht([2, 5 + 4*I, 7], [6*I, 7, 3 + 4*I])
[56 + 68*I, -10 + 30*I, 6 + 50*I, 48 + 32*I]
>>> convolution_fwht([S(33)/7, S(55)/6, S(7)/4], [S(2)/3, 5])
[2057/42, 1870/63, 7/6, 35/4]
References
==========
.. [1] https://www.radioeng.cz/fulltexts/2002/02_03_40_42.pdf
.. [2] https://en.wikipedia.org/wiki/Hadamard_transform
"""
if not a or not b:
return []
a, b = a[:], b[:]
n = max(len(a), len(b))
if n&(n - 1): # not a power of 2
n = 2**n.bit_length()
# padding with zeros
a += [S.Zero]*(n - len(a))
b += [S.Zero]*(n - len(b))
a, b = fwht(a), fwht(b)
a = [expand_mul(x*y) for x, y in zip(a, b)]
a = ifwht(a)
return a
#----------------------------------------------------------------------------#
# #
# Subset Convolution #
# #
#----------------------------------------------------------------------------#
def convolution_subset(a, b):
"""
Performs Subset Convolution of given sequences.
The indices of each argument, considered as bit strings, correspond to
subsets of a finite set.
The sequence is automatically padded to the right with zeros, as the
definition of subset based on bitmasks (indices) requires the size of
sequence to be a power of 2.
Parameters
==========
a, b : iterables
The sequences for which convolution is performed.
Examples
========
>>> from sympy import symbols, S
>>> from sympy.discrete.convolutions import convolution_subset
>>> u, v, x, y, z = symbols('u v x y z')
>>> convolution_subset([u, v], [x, y])
[u*x, u*y + v*x]
>>> convolution_subset([u, v, x], [y, z])
[u*y, u*z + v*y, x*y, x*z]
>>> convolution_subset([1, S(2)/3], [3, 4])
[3, 6]
>>> convolution_subset([1, 3, S(5)/7], [7])
[7, 21, 5, 0]
References
==========
.. [1] https://people.csail.mit.edu/rrw/presentations/subset-conv.pdf
"""
if not a or not b:
return []
if not iterable(a) or not iterable(b):
raise TypeError("Expected a sequence of coefficients for convolution")
a = [sympify(arg) for arg in a]
b = [sympify(arg) for arg in b]
n = max(len(a), len(b))
if n&(n - 1): # not a power of 2
n = 2**n.bit_length()
# padding with zeros
a += [S.Zero]*(n - len(a))
b += [S.Zero]*(n - len(b))
c = [S.Zero]*n
for mask in range(n):
smask = mask
while smask > 0:
c[mask] += expand_mul(a[smask] * b[mask^smask])
smask = (smask - 1)&mask
c[mask] += expand_mul(a[smask] * b[mask^smask])
return c
#----------------------------------------------------------------------------#
# #
# Covering Product #
# #
#----------------------------------------------------------------------------#
def covering_product(a, b):
"""
Returns the covering product of given sequences.
The indices of each argument, considered as bit strings, correspond to
subsets of a finite set.
The covering product of given sequences is a sequence which contains
the sum of products of the elements of the given sequences grouped by
the *bitwise-OR* of the corresponding indices.
The sequence is automatically padded to the right with zeros, as the
definition of subset based on bitmasks (indices) requires the size of
sequence to be a power of 2.
Parameters
==========
a, b : iterables
The sequences for which covering product is to be obtained.
Examples
========
>>> from sympy import symbols, S, I, covering_product
>>> u, v, x, y, z = symbols('u v x y z')
>>> covering_product([u, v], [x, y])
[u*x, u*y + v*x + v*y]
>>> covering_product([u, v, x], [y, z])
[u*y, u*z + v*y + v*z, x*y, x*z]
>>> covering_product([1, S(2)/3], [3, 4 + 5*I])
[3, 26/3 + 25*I/3]
>>> covering_product([1, 3, S(5)/7], [7, 8])
[7, 53, 5, 40/7]
References
==========
.. [1] https://people.csail.mit.edu/rrw/presentations/subset-conv.pdf
"""
if not a or not b:
return []
a, b = a[:], b[:]
n = max(len(a), len(b))
if n&(n - 1): # not a power of 2
n = 2**n.bit_length()
# padding with zeros
a += [S.Zero]*(n - len(a))
b += [S.Zero]*(n - len(b))
a, b = mobius_transform(a), mobius_transform(b)
a = [expand_mul(x*y) for x, y in zip(a, b)]
a = inverse_mobius_transform(a)
return a
#----------------------------------------------------------------------------#
# #
# Intersecting Product #
# #
#----------------------------------------------------------------------------#
def intersecting_product(a, b):
"""
Returns the intersecting product of given sequences.
The indices of each argument, considered as bit strings, correspond to
subsets of a finite set.
The intersecting product of given sequences is the sequence which
contains the sum of products of the elements of the given sequences
grouped by the *bitwise-AND* of the corresponding indices.
The sequence is automatically padded to the right with zeros, as the
definition of subset based on bitmasks (indices) requires the size of
sequence to be a power of 2.
Parameters
==========
a, b : iterables
The sequences for which intersecting product is to be obtained.
Examples
========
>>> from sympy import symbols, S, I, intersecting_product
>>> u, v, x, y, z = symbols('u v x y z')
>>> intersecting_product([u, v], [x, y])
[u*x + u*y + v*x, v*y]
>>> intersecting_product([u, v, x], [y, z])
[u*y + u*z + v*y + x*y + x*z, v*z, 0, 0]
>>> intersecting_product([1, S(2)/3], [3, 4 + 5*I])
[9 + 5*I, 8/3 + 10*I/3]
>>> intersecting_product([1, 3, S(5)/7], [7, 8])
[327/7, 24, 0, 0]
References
==========
.. [1] https://people.csail.mit.edu/rrw/presentations/subset-conv.pdf
"""
if not a or not b:
return []
a, b = a[:], b[:]
n = max(len(a), len(b))
if n&(n - 1): # not a power of 2
n = 2**n.bit_length()
# padding with zeros
a += [S.Zero]*(n - len(a))
b += [S.Zero]*(n - len(b))
a, b = mobius_transform(a, subset=False), mobius_transform(b, subset=False)
a = [expand_mul(x*y) for x, y in zip(a, b)]
a = inverse_mobius_transform(a, subset=False)
return a
#----------------------------------------------------------------------------#
# #
# Integer Convolutions #
# #
#----------------------------------------------------------------------------#
def convolution_int(a, b):
"""Return the convolution of two sequences as a list.
The iterables must consist solely of integers.
Parameters
==========
a, b : Sequence
The sequences for which convolution is performed.
Explanation
===========
This function performs the convolution of ``a`` and ``b`` by packing
each into a single integer, multiplying them together, and then
unpacking the result from the product. The intuition behind this is
that if we evaluate some polynomial [1]:
.. math ::
1156x^6 + 3808x^5 + 8440x^4 + 14856x^3 + 16164x^2 + 14040x + 8100
at say $x = 10^5$ we obtain $1156038080844014856161641404008100$.
Note we can read of the coefficients for each term every five digits.
If the $x$ we chose to evaluate at is large enough, the same will hold
for the product.
The idea now is since big integer multiplication in libraries such
as GMP is highly optimised, this will be reasonably fast.
Examples
========
>>> from sympy.discrete.convolutions import convolution_int
>>> convolution_int([2, 3], [4, 5])
[8, 22, 15]
>>> convolution_int([1, 1, -1], [1, 1])
[1, 2, 0, -1]
References
==========
.. [1] Fateman, Richard J.
Can you save time in multiplying polynomials by encoding them as integers?
University of California, Berkeley, California (2004).
https://people.eecs.berkeley.edu/~fateman/papers/polysbyGMP.pdf
"""
# An upper bound on the largest coefficient in p(x)q(x) is given by (1 + min(dp, dq))N(p)N(q)
# where dp = deg(p), dq = deg(q), N(f) denotes the coefficient of largest modulus in f [1]
B = max(abs(c) for c in a)*max(abs(c) for c in b)*(1 + min(len(a) - 1, len(b) - 1))
x, power = MPZ(1), 0
while x <= (2*B): # multiply by two for negative coefficients, see [1]
x <<= 1
power += 1
def to_integer(poly):
n, mul = MPZ(0), 0
for c in reversed(poly):
if c and not mul: mul = -1 if c < 0 else 1
n <<= power
n += mul*int(c)
return mul, n
# Perform packing and multiplication
(a_mul, a_packed), (b_mul, b_packed) = to_integer(a), to_integer(b)
result = a_packed * b_packed
# Perform unpacking
mul = a_mul * b_mul
mask, half, borrow, poly = x - 1, x >> 1, 0, []
while result or borrow:
coeff = (result & mask) + borrow
result >>= power
borrow = coeff >= half
poly.append(mul * int(coeff if coeff < half else coeff - x))
return poly or [0]
PK ]ZZZs��� sympy/discrete/recurrences.py"""
Recurrences
"""
from sympy.core import S, sympify
from sympy.utilities.iterables import iterable
from sympy.utilities.misc import as_int
def linrec(coeffs, init, n):
r"""
Evaluation of univariate linear recurrences of homogeneous type
having coefficients independent of the recurrence variable.
Parameters
==========
coeffs : iterable
Coefficients of the recurrence
init : iterable
Initial values of the recurrence
n : Integer
Point of evaluation for the recurrence
Notes
=====
Let `y(n)` be the recurrence of given type, ``c`` be the sequence
of coefficients, ``b`` be the sequence of initial/base values of the
recurrence and ``k`` (equal to ``len(c)``) be the order of recurrence.
Then,
.. math :: y(n) = \begin{cases} b_n & 0 \le n < k \\
c_0 y(n-1) + c_1 y(n-2) + \cdots + c_{k-1} y(n-k) & n \ge k
\end{cases}
Let `x_0, x_1, \ldots, x_n` be a sequence and consider the transformation
that maps each polynomial `f(x)` to `T(f(x))` where each power `x^i` is
replaced by the corresponding value `x_i`. The sequence is then a solution
of the recurrence if and only if `T(x^i p(x)) = 0` for each `i \ge 0` where
`p(x) = x^k - c_0 x^(k-1) - \cdots - c_{k-1}` is the characteristic
polynomial.
Then `T(f(x)p(x)) = 0` for each polynomial `f(x)` (as it is a linear
combination of powers `x^i`). Now, if `x^n` is congruent to
`g(x) = a_0 x^0 + a_1 x^1 + \cdots + a_{k-1} x^{k-1}` modulo `p(x)`, then
`T(x^n) = x_n` is equal to
`T(g(x)) = a_0 x_0 + a_1 x_1 + \cdots + a_{k-1} x_{k-1}`.
Computation of `x^n`,
given `x^k = c_0 x^{k-1} + c_1 x^{k-2} + \cdots + c_{k-1}`
is performed using exponentiation by squaring (refer to [1_]) with
an additional reduction step performed to retain only first `k` powers
of `x` in the representation of `x^n`.
Examples
========
>>> from sympy.discrete.recurrences import linrec
>>> from sympy.abc import x, y, z
>>> linrec(coeffs=[1, 1], init=[0, 1], n=10)
55
>>> linrec(coeffs=[1, 1], init=[x, y], n=10)
34*x + 55*y
>>> linrec(coeffs=[x, y], init=[0, 1], n=5)
x**2*y + x*(x**3 + 2*x*y) + y**2
>>> linrec(coeffs=[1, 2, 3, 0, 0, 4], init=[x, y, z], n=16)
13576*x + 5676*y + 2356*z
References
==========
.. [1] https://en.wikipedia.org/wiki/Exponentiation_by_squaring
.. [2] https://en.wikipedia.org/w/index.php?title=Modular_exponentiation§ion=6#Matrices
See Also
========
sympy.polys.agca.extensions.ExtensionElement.__pow__
"""
if not coeffs:
return S.Zero
if not iterable(coeffs):
raise TypeError("Expected a sequence of coefficients for"
" the recurrence")
if not iterable(init):
raise TypeError("Expected a sequence of values for the initialization"
" of the recurrence")
n = as_int(n)
if n < 0:
raise ValueError("Point of evaluation of recurrence must be a "
"non-negative integer")
c = [sympify(arg) for arg in coeffs]
b = [sympify(arg) for arg in init]
k = len(c)
if len(b) > k:
raise TypeError("Count of initial values should not exceed the "
"order of the recurrence")
else:
b += [S.Zero]*(k - len(b)) # remaining initial values default to zero
if n < k:
return b[n]
terms = [u*v for u, v in zip(linrec_coeffs(c, n), b)]
return sum(terms[:-1], terms[-1])
def linrec_coeffs(c, n):
r"""
Compute the coefficients of n'th term in linear recursion
sequence defined by c.
`x^k = c_0 x^{k-1} + c_1 x^{k-2} + \cdots + c_{k-1}`.
It computes the coefficients by using binary exponentiation.
This function is used by `linrec` and `_eval_pow_by_cayley`.
Parameters
==========
c = coefficients of the divisor polynomial
n = exponent of x, so dividend is x^n
"""
k = len(c)
def _square_and_reduce(u, offset):
# squares `(u_0 + u_1 x + u_2 x^2 + \cdots + u_{k-1} x^k)` (and
# multiplies by `x` if offset is 1) and reduces the above result of
# length upto `2k` to `k` using the characteristic equation of the
# recurrence given by, `x^k = c_0 x^{k-1} + c_1 x^{k-2} + \cdots + c_{k-1}`
w = [S.Zero]*(2*len(u) - 1 + offset)
for i, p in enumerate(u):
for j, q in enumerate(u):
w[offset + i + j] += p*q
for j in range(len(w) - 1, k - 1, -1):
for i in range(k):
w[j - i - 1] += w[j]*c[i]
return w[:k]
def _final_coeffs(n):
# computes the final coefficient list - `cf` corresponding to the
# point at which recurrence is to be evalauted - `n`, such that,
# `y(n) = cf_0 y(k-1) + cf_1 y(k-2) + \cdots + cf_{k-1} y(0)`
if n < k:
return [S.Zero]*n + [S.One] + [S.Zero]*(k - n - 1)
else:
return _square_and_reduce(_final_coeffs(n // 2), n % 2)
return _final_coeffs(n)
PK ]ZZZ|��S�- �- sympy/discrete/transforms.py"""
Discrete Fourier Transform, Number Theoretic Transform,
Walsh Hadamard Transform, Mobius Transform
"""
from sympy.core import S, Symbol, sympify
from sympy.core.function import expand_mul
from sympy.core.numbers import pi, I
from sympy.functions.elementary.trigonometric import sin, cos
from sympy.ntheory import isprime, primitive_root
from sympy.utilities.iterables import ibin, iterable
from sympy.utilities.misc import as_int
#----------------------------------------------------------------------------#
# #
# Discrete Fourier Transform #
# #
#----------------------------------------------------------------------------#
def _fourier_transform(seq, dps, inverse=False):
"""Utility function for the Discrete Fourier Transform"""
if not iterable(seq):
raise TypeError("Expected a sequence of numeric coefficients "
"for Fourier Transform")
a = [sympify(arg) for arg in seq]
if any(x.has(Symbol) for x in a):
raise ValueError("Expected non-symbolic coefficients")
n = len(a)
if n < 2:
return a
b = n.bit_length() - 1
if n&(n - 1): # not a power of 2
b += 1
n = 2**b
a += [S.Zero]*(n - len(a))
for i in range(1, n):
j = int(ibin(i, b, str=True)[::-1], 2)
if i < j:
a[i], a[j] = a[j], a[i]
ang = -2*pi/n if inverse else 2*pi/n
if dps is not None:
ang = ang.evalf(dps + 2)
w = [cos(ang*i) + I*sin(ang*i) for i in range(n // 2)]
h = 2
while h <= n:
hf, ut = h // 2, n // h
for i in range(0, n, h):
for j in range(hf):
u, v = a[i + j], expand_mul(a[i + j + hf]*w[ut * j])
a[i + j], a[i + j + hf] = u + v, u - v
h *= 2
if inverse:
a = [(x/n).evalf(dps) for x in a] if dps is not None \
else [x/n for x in a]
return a
def fft(seq, dps=None):
r"""
Performs the Discrete Fourier Transform (**DFT**) in the complex domain.
The sequence is automatically padded to the right with zeros, as the
*radix-2 FFT* requires the number of sample points to be a power of 2.
This method should be used with default arguments only for short sequences
as the complexity of expressions increases with the size of the sequence.
Parameters
==========
seq : iterable
The sequence on which **DFT** is to be applied.
dps : Integer
Specifies the number of decimal digits for precision.
Examples
========
>>> from sympy import fft, ifft
>>> fft([1, 2, 3, 4])
[10, -2 - 2*I, -2, -2 + 2*I]
>>> ifft(_)
[1, 2, 3, 4]
>>> ifft([1, 2, 3, 4])
[5/2, -1/2 + I/2, -1/2, -1/2 - I/2]
>>> fft(_)
[1, 2, 3, 4]
>>> ifft([1, 7, 3, 4], dps=15)
[3.75, -0.5 - 0.75*I, -1.75, -0.5 + 0.75*I]
>>> fft(_)
[1.0, 7.0, 3.0, 4.0]
References
==========
.. [1] https://en.wikipedia.org/wiki/Cooley%E2%80%93Tukey_FFT_algorithm
.. [2] https://mathworld.wolfram.com/FastFourierTransform.html
"""
return _fourier_transform(seq, dps=dps)
def ifft(seq, dps=None):
return _fourier_transform(seq, dps=dps, inverse=True)
ifft.__doc__ = fft.__doc__
#----------------------------------------------------------------------------#
# #
# Number Theoretic Transform #
# #
#----------------------------------------------------------------------------#
def _number_theoretic_transform(seq, prime, inverse=False):
"""Utility function for the Number Theoretic Transform"""
if not iterable(seq):
raise TypeError("Expected a sequence of integer coefficients "
"for Number Theoretic Transform")
p = as_int(prime)
if not isprime(p):
raise ValueError("Expected prime modulus for "
"Number Theoretic Transform")
a = [as_int(x) % p for x in seq]
n = len(a)
if n < 1:
return a
b = n.bit_length() - 1
if n&(n - 1):
b += 1
n = 2**b
if (p - 1) % n:
raise ValueError("Expected prime modulus of the form (m*2**k + 1)")
a += [0]*(n - len(a))
for i in range(1, n):
j = int(ibin(i, b, str=True)[::-1], 2)
if i < j:
a[i], a[j] = a[j], a[i]
pr = primitive_root(p)
rt = pow(pr, (p - 1) // n, p)
if inverse:
rt = pow(rt, p - 2, p)
w = [1]*(n // 2)
for i in range(1, n // 2):
w[i] = w[i - 1]*rt % p
h = 2
while h <= n:
hf, ut = h // 2, n // h
for i in range(0, n, h):
for j in range(hf):
u, v = a[i + j], a[i + j + hf]*w[ut * j]
a[i + j], a[i + j + hf] = (u + v) % p, (u - v) % p
h *= 2
if inverse:
rv = pow(n, p - 2, p)
a = [x*rv % p for x in a]
return a
def ntt(seq, prime):
r"""
Performs the Number Theoretic Transform (**NTT**), which specializes the
Discrete Fourier Transform (**DFT**) over quotient ring `Z/pZ` for prime
`p` instead of complex numbers `C`.
The sequence is automatically padded to the right with zeros, as the
*radix-2 NTT* requires the number of sample points to be a power of 2.
Parameters
==========
seq : iterable
The sequence on which **DFT** is to be applied.
prime : Integer
Prime modulus of the form `(m 2^k + 1)` to be used for performing
**NTT** on the sequence.
Examples
========
>>> from sympy import ntt, intt
>>> ntt([1, 2, 3, 4], prime=3*2**8 + 1)
[10, 643, 767, 122]
>>> intt(_, 3*2**8 + 1)
[1, 2, 3, 4]
>>> intt([1, 2, 3, 4], prime=3*2**8 + 1)
[387, 415, 384, 353]
>>> ntt(_, prime=3*2**8 + 1)
[1, 2, 3, 4]
References
==========
.. [1] http://www.apfloat.org/ntt.html
.. [2] https://mathworld.wolfram.com/NumberTheoreticTransform.html
.. [3] https://en.wikipedia.org/wiki/Discrete_Fourier_transform_(general%29
"""
return _number_theoretic_transform(seq, prime=prime)
def intt(seq, prime):
return _number_theoretic_transform(seq, prime=prime, inverse=True)
intt.__doc__ = ntt.__doc__
#----------------------------------------------------------------------------#
# #
# Walsh Hadamard Transform #
# #
#----------------------------------------------------------------------------#
def _walsh_hadamard_transform(seq, inverse=False):
"""Utility function for the Walsh Hadamard Transform"""
if not iterable(seq):
raise TypeError("Expected a sequence of coefficients "
"for Walsh Hadamard Transform")
a = [sympify(arg) for arg in seq]
n = len(a)
if n < 2:
return a
if n&(n - 1):
n = 2**n.bit_length()
a += [S.Zero]*(n - len(a))
h = 2
while h <= n:
hf = h // 2
for i in range(0, n, h):
for j in range(hf):
u, v = a[i + j], a[i + j + hf]
a[i + j], a[i + j + hf] = u + v, u - v
h *= 2
if inverse:
a = [x/n for x in a]
return a
def fwht(seq):
r"""
Performs the Walsh Hadamard Transform (**WHT**), and uses Hadamard
ordering for the sequence.
The sequence is automatically padded to the right with zeros, as the
*radix-2 FWHT* requires the number of sample points to be a power of 2.
Parameters
==========
seq : iterable
The sequence on which WHT is to be applied.
Examples
========
>>> from sympy import fwht, ifwht
>>> fwht([4, 2, 2, 0, 0, 2, -2, 0])
[8, 0, 8, 0, 8, 8, 0, 0]
>>> ifwht(_)
[4, 2, 2, 0, 0, 2, -2, 0]
>>> ifwht([19, -1, 11, -9, -7, 13, -15, 5])
[2, 0, 4, 0, 3, 10, 0, 0]
>>> fwht(_)
[19, -1, 11, -9, -7, 13, -15, 5]
References
==========
.. [1] https://en.wikipedia.org/wiki/Hadamard_transform
.. [2] https://en.wikipedia.org/wiki/Fast_Walsh%E2%80%93Hadamard_transform
"""
return _walsh_hadamard_transform(seq)
def ifwht(seq):
return _walsh_hadamard_transform(seq, inverse=True)
ifwht.__doc__ = fwht.__doc__
#----------------------------------------------------------------------------#
# #
# Mobius Transform for Subset Lattice #
# #
#----------------------------------------------------------------------------#
def _mobius_transform(seq, sgn, subset):
r"""Utility function for performing Mobius Transform using
Yate's Dynamic Programming method"""
if not iterable(seq):
raise TypeError("Expected a sequence of coefficients")
a = [sympify(arg) for arg in seq]
n = len(a)
if n < 2:
return a
if n&(n - 1):
n = 2**n.bit_length()
a += [S.Zero]*(n - len(a))
if subset:
i = 1
while i < n:
for j in range(n):
if j & i:
a[j] += sgn*a[j ^ i]
i *= 2
else:
i = 1
while i < n:
for j in range(n):
if j & i:
continue
a[j] += sgn*a[j ^ i]
i *= 2
return a
def mobius_transform(seq, subset=True):
r"""
Performs the Mobius Transform for subset lattice with indices of
sequence as bitmasks.
The indices of each argument, considered as bit strings, correspond
to subsets of a finite set.
The sequence is automatically padded to the right with zeros, as the
definition of subset/superset based on bitmasks (indices) requires
the size of sequence to be a power of 2.
Parameters
==========
seq : iterable
The sequence on which Mobius Transform is to be applied.
subset : bool
Specifies if Mobius Transform is applied by enumerating subsets
or supersets of the given set.
Examples
========
>>> from sympy import symbols
>>> from sympy import mobius_transform, inverse_mobius_transform
>>> x, y, z = symbols('x y z')
>>> mobius_transform([x, y, z])
[x, x + y, x + z, x + y + z]
>>> inverse_mobius_transform(_)
[x, y, z, 0]
>>> mobius_transform([x, y, z], subset=False)
[x + y + z, y, z, 0]
>>> inverse_mobius_transform(_, subset=False)
[x, y, z, 0]
>>> mobius_transform([1, 2, 3, 4])
[1, 3, 4, 10]
>>> inverse_mobius_transform(_)
[1, 2, 3, 4]
>>> mobius_transform([1, 2, 3, 4], subset=False)
[10, 6, 7, 4]
>>> inverse_mobius_transform(_, subset=False)
[1, 2, 3, 4]
References
==========
.. [1] https://en.wikipedia.org/wiki/M%C3%B6bius_inversion_formula
.. [2] https://people.csail.mit.edu/rrw/presentations/subset-conv.pdf
.. [3] https://arxiv.org/pdf/1211.0189.pdf
"""
return _mobius_transform(seq, sgn=+1, subset=subset)
def inverse_mobius_transform(seq, subset=True):
return _mobius_transform(seq, sgn=-1, subset=subset)
inverse_mobius_transform.__doc__ = mobius_transform.__doc__
PK ]ZZZțu�B B sympy/external/__init__.py"""
Unified place for determining if external dependencies are installed or not.
You should import all external modules using the import_module() function.
For example
>>> from sympy.external import import_module
>>> numpy = import_module('numpy')
If the resulting library is not installed, or if the installed version
is less than a given minimum version, the function will return None.
Otherwise, it will return the library. See the docstring of
import_module() for more information.
"""
from sympy.external.importtools import import_module
__all__ = ['import_module']
PK ]ZZZg�P& & sympy/external/gmpy.pyimport os
from ctypes import c_long, sizeof
from functools import reduce
from typing import Tuple as tTuple, Type
from warnings import warn
from sympy.external import import_module
from .pythonmpq import PythonMPQ
from .ntheory import (
bit_scan1 as python_bit_scan1,
bit_scan0 as python_bit_scan0,
remove as python_remove,
factorial as python_factorial,
sqrt as python_sqrt,
sqrtrem as python_sqrtrem,
gcd as python_gcd,
lcm as python_lcm,
gcdext as python_gcdext,
is_square as python_is_square,
invert as python_invert,
legendre as python_legendre,
jacobi as python_jacobi,
kronecker as python_kronecker,
iroot as python_iroot,
is_fermat_prp as python_is_fermat_prp,
is_euler_prp as python_is_euler_prp,
is_strong_prp as python_is_strong_prp,
is_fibonacci_prp as python_is_fibonacci_prp,
is_lucas_prp as python_is_lucas_prp,
is_selfridge_prp as python_is_selfridge_prp,
is_strong_lucas_prp as python_is_strong_lucas_prp,
is_strong_selfridge_prp as python_is_strong_selfridge_prp,
is_bpsw_prp as python_is_bpsw_prp,
is_strong_bpsw_prp as python_is_strong_bpsw_prp,
)
__all__ = [
# GROUND_TYPES is either 'gmpy' or 'python' depending on which is used. If
# gmpy is installed then it will be used unless the environment variable
# SYMPY_GROUND_TYPES is set to something other than 'auto', 'gmpy', or
# 'gmpy2'.
'GROUND_TYPES',
# If HAS_GMPY is 0, no supported version of gmpy is available. Otherwise,
# HAS_GMPY will be 2 for gmpy2 if GROUND_TYPES is 'gmpy'. It used to be
# possible for HAS_GMPY to be 1 for gmpy but gmpy is no longer supported.
'HAS_GMPY',
# SYMPY_INTS is a tuple containing the base types for valid integer types.
# This is either (int,) or (int, type(mpz(0))) depending on GROUND_TYPES.
'SYMPY_INTS',
# MPQ is either gmpy.mpq or the Python equivalent from
# sympy.external.pythonmpq
'MPQ',
# MPZ is either gmpy.mpz or int.
'MPZ',
'bit_scan1',
'bit_scan0',
'remove',
'factorial',
'sqrt',
'is_square',
'sqrtrem',
'gcd',
'lcm',
'gcdext',
'invert',
'legendre',
'jacobi',
'kronecker',
'iroot',
'is_fermat_prp',
'is_euler_prp',
'is_strong_prp',
'is_fibonacci_prp',
'is_lucas_prp',
'is_selfridge_prp',
'is_strong_lucas_prp',
'is_strong_selfridge_prp',
'is_bpsw_prp',
'is_strong_bpsw_prp',
]
#
# Tested python-flint version. Future versions might work but we will only use
# them if explicitly requested by SYMPY_GROUND_TYPES=flint.
#
_PYTHON_FLINT_VERSION_NEEDED = ["0.6", "0.7", "0.8", "0.9"]
def _flint_version_okay(flint_version):
major, minor = flint_version.split('.')[:2]
flint_ver = f'{major}.{minor}'
return flint_ver in _PYTHON_FLINT_VERSION_NEEDED
#
# We will only use gmpy2 >= 2.0.0
#
_GMPY2_MIN_VERSION = '2.0.0'
def _get_flint(sympy_ground_types):
if sympy_ground_types not in ('auto', 'flint'):
return None
try:
import flint
# Earlier versions of python-flint may not have __version__.
from flint import __version__ as _flint_version
except ImportError:
if sympy_ground_types == 'flint':
warn("SYMPY_GROUND_TYPES was set to flint but python-flint is not "
"installed. Falling back to other ground types.")
return None
if _flint_version_okay(_flint_version):
return flint
elif sympy_ground_types == 'auto':
return None
else:
warn(f"Using python-flint {_flint_version} because SYMPY_GROUND_TYPES "
f"is set to flint but this version of SymPy is only tested "
f"with python-flint versions {_PYTHON_FLINT_VERSION_NEEDED}.")
return flint
def _get_gmpy2(sympy_ground_types):
if sympy_ground_types not in ('auto', 'gmpy', 'gmpy2'):
return None
gmpy = import_module('gmpy2', min_module_version=_GMPY2_MIN_VERSION,
module_version_attr='version', module_version_attr_call_args=())
if sympy_ground_types != 'auto' and gmpy is None:
warn("gmpy2 library is not installed, switching to 'python' ground types")
return gmpy
#
# SYMPY_GROUND_TYPES can be flint, gmpy, gmpy2, python or auto (default)
#
_SYMPY_GROUND_TYPES = os.environ.get('SYMPY_GROUND_TYPES', 'auto').lower()
_flint = None
_gmpy = None
#
# First handle auto-detection of flint/gmpy2. We will prefer flint if available
# or otherwise gmpy2 if available and then lastly the python types.
#
if _SYMPY_GROUND_TYPES in ('auto', 'flint'):
_flint = _get_flint(_SYMPY_GROUND_TYPES)
if _flint is not None:
_SYMPY_GROUND_TYPES = 'flint'
else:
_SYMPY_GROUND_TYPES = 'auto'
if _SYMPY_GROUND_TYPES in ('auto', 'gmpy', 'gmpy2'):
_gmpy = _get_gmpy2(_SYMPY_GROUND_TYPES)
if _gmpy is not None:
_SYMPY_GROUND_TYPES = 'gmpy'
else:
_SYMPY_GROUND_TYPES = 'python'
if _SYMPY_GROUND_TYPES not in ('flint', 'gmpy', 'python'):
warn("SYMPY_GROUND_TYPES environment variable unrecognised. "
"Should be 'auto', 'flint', 'gmpy', 'gmpy2' or 'python'.")
_SYMPY_GROUND_TYPES = 'python'
#
# At this point _SYMPY_GROUND_TYPES is either flint, gmpy or python. The blocks
# below define the values exported by this module in each case.
#
#
# In gmpy2 and flint, there are functions that take a long (or unsigned long)
# argument. That is, it is not possible to input a value larger than that.
#
LONG_MAX = (1 << (8*sizeof(c_long) - 1)) - 1
#
# Type checkers are confused by what SYMPY_INTS is. There may be a better type
# hint for this like Type[Integral] or something.
#
SYMPY_INTS: tTuple[Type, ...]
if _SYMPY_GROUND_TYPES == 'gmpy':
assert _gmpy is not None
flint = None
gmpy = _gmpy
HAS_GMPY = 2
GROUND_TYPES = 'gmpy'
SYMPY_INTS = (int, type(gmpy.mpz(0)))
MPZ = gmpy.mpz
MPQ = gmpy.mpq
bit_scan1 = gmpy.bit_scan1
bit_scan0 = gmpy.bit_scan0
remove = gmpy.remove
factorial = gmpy.fac
sqrt = gmpy.isqrt
is_square = gmpy.is_square
sqrtrem = gmpy.isqrt_rem
gcd = gmpy.gcd
lcm = gmpy.lcm
gcdext = gmpy.gcdext
invert = gmpy.invert
legendre = gmpy.legendre
jacobi = gmpy.jacobi
kronecker = gmpy.kronecker
def iroot(x, n):
# In the latest gmpy2, the threshold for n is ULONG_MAX,
# but adjust to the older one.
if n <= LONG_MAX:
return gmpy.iroot(x, n)
return python_iroot(x, n)
is_fermat_prp = gmpy.is_fermat_prp
is_euler_prp = gmpy.is_euler_prp
is_strong_prp = gmpy.is_strong_prp
is_fibonacci_prp = gmpy.is_fibonacci_prp
is_lucas_prp = gmpy.is_lucas_prp
is_selfridge_prp = gmpy.is_selfridge_prp
is_strong_lucas_prp = gmpy.is_strong_lucas_prp
is_strong_selfridge_prp = gmpy.is_strong_selfridge_prp
is_bpsw_prp = gmpy.is_bpsw_prp
is_strong_bpsw_prp = gmpy.is_strong_bpsw_prp
elif _SYMPY_GROUND_TYPES == 'flint':
assert _flint is not None
flint = _flint
gmpy = None
HAS_GMPY = 0
GROUND_TYPES = 'flint'
SYMPY_INTS = (int, flint.fmpz) # type: ignore
MPZ = flint.fmpz # type: ignore
MPQ = flint.fmpq # type: ignore
bit_scan1 = python_bit_scan1
bit_scan0 = python_bit_scan0
remove = python_remove
factorial = python_factorial
def sqrt(x):
return flint.fmpz(x).isqrt()
def is_square(x):
if x < 0:
return False
return flint.fmpz(x).sqrtrem()[1] == 0
def sqrtrem(x):
return flint.fmpz(x).sqrtrem()
def gcd(*args):
return reduce(flint.fmpz.gcd, args, flint.fmpz(0))
def lcm(*args):
return reduce(flint.fmpz.lcm, args, flint.fmpz(1))
gcdext = python_gcdext
invert = python_invert
legendre = python_legendre
def jacobi(x, y):
if y <= 0 or not y % 2:
raise ValueError("y should be an odd positive integer")
return flint.fmpz(x).jacobi(y)
kronecker = python_kronecker
def iroot(x, n):
if n <= LONG_MAX:
y = flint.fmpz(x).root(n)
return y, y**n == x
return python_iroot(x, n)
is_fermat_prp = python_is_fermat_prp
is_euler_prp = python_is_euler_prp
is_strong_prp = python_is_strong_prp
is_fibonacci_prp = python_is_fibonacci_prp
is_lucas_prp = python_is_lucas_prp
is_selfridge_prp = python_is_selfridge_prp
is_strong_lucas_prp = python_is_strong_lucas_prp
is_strong_selfridge_prp = python_is_strong_selfridge_prp
is_bpsw_prp = python_is_bpsw_prp
is_strong_bpsw_prp = python_is_strong_bpsw_prp
elif _SYMPY_GROUND_TYPES == 'python':
flint = None
gmpy = None
HAS_GMPY = 0
GROUND_TYPES = 'python'
SYMPY_INTS = (int,)
MPZ = int
MPQ = PythonMPQ
bit_scan1 = python_bit_scan1
bit_scan0 = python_bit_scan0
remove = python_remove
factorial = python_factorial
sqrt = python_sqrt
is_square = python_is_square
sqrtrem = python_sqrtrem
gcd = python_gcd
lcm = python_lcm
gcdext = python_gcdext
invert = python_invert
legendre = python_legendre
jacobi = python_jacobi
kronecker = python_kronecker
iroot = python_iroot
is_fermat_prp = python_is_fermat_prp
is_euler_prp = python_is_euler_prp
is_strong_prp = python_is_strong_prp
is_fibonacci_prp = python_is_fibonacci_prp
is_lucas_prp = python_is_lucas_prp
is_selfridge_prp = python_is_selfridge_prp
is_strong_lucas_prp = python_is_strong_lucas_prp
is_strong_selfridge_prp = python_is_strong_selfridge_prp
is_bpsw_prp = python_is_bpsw_prp
is_strong_bpsw_prp = python_is_strong_bpsw_prp
else:
assert False
PK ]ZZZ��C� � sympy/external/importtools.py"""Tools to assist importing optional external modules."""
import sys
import re
# Override these in the module to change the default warning behavior.
# For example, you might set both to False before running the tests so that
# warnings are not printed to the console, or set both to True for debugging.
WARN_NOT_INSTALLED = None # Default is False
WARN_OLD_VERSION = None # Default is True
def __sympy_debug():
# helper function from sympy/__init__.py
# We don't just import SYMPY_DEBUG from that file because we don't want to
# import all of SymPy just to use this module.
import os
debug_str = os.getenv('SYMPY_DEBUG', 'False')
if debug_str in ('True', 'False'):
return eval(debug_str)
else:
raise RuntimeError("unrecognized value for SYMPY_DEBUG: %s" %
debug_str)
if __sympy_debug():
WARN_OLD_VERSION = True
WARN_NOT_INSTALLED = True
_component_re = re.compile(r'(\d+ | [a-z]+ | \.)', re.VERBOSE)
def version_tuple(vstring):
# Parse a version string to a tuple e.g. '1.2' -> (1, 2)
# Simplified from distutils.version.LooseVersion which was deprecated in
# Python 3.10.
components = []
for x in _component_re.split(vstring):
if x and x != '.':
try:
x = int(x)
except ValueError:
pass
components.append(x)
return tuple(components)
def import_module(module, min_module_version=None, min_python_version=None,
warn_not_installed=None, warn_old_version=None,
module_version_attr='__version__', module_version_attr_call_args=None,
import_kwargs={}, catch=()):
"""
Import and return a module if it is installed.
If the module is not installed, it returns None.
A minimum version for the module can be given as the keyword argument
min_module_version. This should be comparable against the module version.
By default, module.__version__ is used to get the module version. To
override this, set the module_version_attr keyword argument. If the
attribute of the module to get the version should be called (e.g.,
module.version()), then set module_version_attr_call_args to the args such
that module.module_version_attr(*module_version_attr_call_args) returns the
module's version.
If the module version is less than min_module_version using the Python <
comparison, None will be returned, even if the module is installed. You can
use this to keep from importing an incompatible older version of a module.
You can also specify a minimum Python version by using the
min_python_version keyword argument. This should be comparable against
sys.version_info.
If the keyword argument warn_not_installed is set to True, the function will
emit a UserWarning when the module is not installed.
If the keyword argument warn_old_version is set to True, the function will
emit a UserWarning when the library is installed, but cannot be imported
because of the min_module_version or min_python_version options.
Note that because of the way warnings are handled, a warning will be
emitted for each module only once. You can change the default warning
behavior by overriding the values of WARN_NOT_INSTALLED and WARN_OLD_VERSION
in sympy.external.importtools. By default, WARN_NOT_INSTALLED is False and
WARN_OLD_VERSION is True.
This function uses __import__() to import the module. To pass additional
options to __import__(), use the import_kwargs keyword argument. For
example, to import a submodule A.B, you must pass a nonempty fromlist option
to __import__. See the docstring of __import__().
This catches ImportError to determine if the module is not installed. To
catch additional errors, pass them as a tuple to the catch keyword
argument.
Examples
========
>>> from sympy.external import import_module
>>> numpy = import_module('numpy')
>>> numpy = import_module('numpy', min_python_version=(2, 7),
... warn_old_version=False)
>>> numpy = import_module('numpy', min_module_version='1.5',
... warn_old_version=False) # numpy.__version__ is a string
>>> # gmpy does not have __version__, but it does have gmpy.version()
>>> gmpy = import_module('gmpy', min_module_version='1.14',
... module_version_attr='version', module_version_attr_call_args=(),
... warn_old_version=False)
>>> # To import a submodule, you must pass a nonempty fromlist to
>>> # __import__(). The values do not matter.
>>> p3 = import_module('mpl_toolkits.mplot3d',
... import_kwargs={'fromlist':['something']})
>>> # matplotlib.pyplot can raise RuntimeError when the display cannot be opened
>>> matplotlib = import_module('matplotlib',
... import_kwargs={'fromlist':['pyplot']}, catch=(RuntimeError,))
"""
# keyword argument overrides default, and global variable overrides
# keyword argument.
warn_old_version = (WARN_OLD_VERSION if WARN_OLD_VERSION is not None
else warn_old_version or True)
warn_not_installed = (WARN_NOT_INSTALLED if WARN_NOT_INSTALLED is not None
else warn_not_installed or False)
import warnings
# Check Python first so we don't waste time importing a module we can't use
if min_python_version:
if sys.version_info < min_python_version:
if warn_old_version:
warnings.warn("Python version is too old to use %s "
"(%s or newer required)" % (
module, '.'.join(map(str, min_python_version))),
UserWarning, stacklevel=2)
return
try:
mod = __import__(module, **import_kwargs)
## there's something funny about imports with matplotlib and py3k. doing
## from matplotlib import collections
## gives python's stdlib collections module. explicitly re-importing
## the module fixes this.
from_list = import_kwargs.get('fromlist', ())
for submod in from_list:
if submod == 'collections' and mod.__name__ == 'matplotlib':
__import__(module + '.' + submod)
except ImportError:
if warn_not_installed:
warnings.warn("%s module is not installed" % module, UserWarning,
stacklevel=2)
return
except catch as e:
if warn_not_installed:
warnings.warn(
"%s module could not be used (%s)" % (module, repr(e)),
stacklevel=2)
return
if min_module_version:
modversion = getattr(mod, module_version_attr)
if module_version_attr_call_args is not None:
modversion = modversion(*module_version_attr_call_args)
if version_tuple(modversion) < version_tuple(min_module_version):
if warn_old_version:
# Attempt to create a pretty string version of the version
if isinstance(min_module_version, str):
verstr = min_module_version
elif isinstance(min_module_version, (tuple, list)):
verstr = '.'.join(map(str, min_module_version))
else:
# Either don't know what this is. Hopefully
# it's something that has a nice str version, like an int.
verstr = str(min_module_version)
warnings.warn("%s version is too old to use "
"(%s or newer required)" % (module, verstr),
UserWarning, stacklevel=2)
return
return mod
PK ]ZZZn��B �B sympy/external/ntheory.py# sympy.external.ntheory
#
# This module provides pure Python implementations of some number theory
# functions that are alternately used from gmpy2 if it is installed.
import sys
import math
import mpmath.libmp as mlib
_small_trailing = [0] * 256
for j in range(1, 8):
_small_trailing[1 << j :: 1 << (j + 1)] = [j] * (1 << (7 - j))
def bit_scan1(x, n=0):
if not x:
return
x = abs(x >> n)
low_byte = x & 0xFF
if low_byte:
return _small_trailing[low_byte] + n
t = 8 + n
x >>= 8
# 2**m is quick for z up through 2**30
z = x.bit_length() - 1
if x == 1 << z:
return z + t
if z < 300:
# fixed 8-byte reduction
while not x & 0xFF:
x >>= 8
t += 8
else:
# binary reduction important when there might be a large
# number of trailing 0s
p = z >> 1
while not x & 0xFF:
while x & ((1 << p) - 1):
p >>= 1
x >>= p
t += p
return t + _small_trailing[x & 0xFF]
def bit_scan0(x, n=0):
return bit_scan1(x + (1 << n), n)
def remove(x, f):
if f < 2:
raise ValueError("factor must be > 1")
if x == 0:
return 0, 0
if f == 2:
b = bit_scan1(x)
return x >> b, b
m = 0
y, rem = divmod(x, f)
while not rem:
x = y
m += 1
if m > 5:
pow_list = [f**2]
while pow_list:
_f = pow_list[-1]
y, rem = divmod(x, _f)
if not rem:
m += 1 << len(pow_list)
x = y
pow_list.append(_f**2)
else:
pow_list.pop()
y, rem = divmod(x, f)
return x, m
def factorial(x):
"""Return x!."""
return int(mlib.ifac(int(x)))
def sqrt(x):
"""Integer square root of x."""
return int(mlib.isqrt(int(x)))
def sqrtrem(x):
"""Integer square root of x and remainder."""
s, r = mlib.sqrtrem(int(x))
return (int(s), int(r))
if sys.version_info[:2] >= (3, 9):
# As of Python 3.9 these can take multiple arguments
gcd = math.gcd
lcm = math.lcm
else:
# Until python 3.8 is no longer supported
from functools import reduce
def gcd(*args):
"""gcd of multiple integers."""
return reduce(math.gcd, args, 0)
def lcm(*args):
"""lcm of multiple integers."""
if 0 in args:
return 0
return reduce(lambda x, y: x*y//math.gcd(x, y), args, 1)
def _sign(n):
if n < 0:
return -1, -n
return 1, n
def gcdext(a, b):
if not a or not b:
g = abs(a) or abs(b)
if not g:
return (0, 0, 0)
return (g, a // g, b // g)
x_sign, a = _sign(a)
y_sign, b = _sign(b)
x, r = 1, 0
y, s = 0, 1
while b:
q, c = divmod(a, b)
a, b = b, c
x, r = r, x - q*r
y, s = s, y - q*s
return (a, x * x_sign, y * y_sign)
def is_square(x):
"""Return True if x is a square number."""
if x < 0:
return False
# Note that the possible values of y**2 % n for a given n are limited.
# For example, when n=4, y**2 % n can only take 0 or 1.
# In other words, if x % 4 is 2 or 3, then x is not a square number.
# Mathematically, it determines if it belongs to the set {y**2 % n},
# but implementationally, it can be realized as a logical conjunction
# with an n-bit integer.
# see https://mersenneforum.org/showpost.php?p=110896
# def magic(n):
# s = {y**2 % n for y in range(n)}
# s = set(range(n)) - s
# return sum(1 << bit for bit in s)
# >>> print(hex(magic(128)))
# 0xfdfdfdedfdfdfdecfdfdfdedfdfcfdec
# >>> print(hex(magic(99)))
# 0x5f6f9ffb6fb7ddfcb75befdec
# >>> print(hex(magic(91)))
# 0x6fd1bfcfed5f3679d3ebdec
# >>> print(hex(magic(85)))
# 0xdef9ae771ffe3b9d67dec
if 0xfdfdfdedfdfdfdecfdfdfdedfdfcfdec & (1 << (x & 127)):
return False # e.g. 2, 3
m = x % 765765 # 765765 = 99 * 91 * 85
if 0x5f6f9ffb6fb7ddfcb75befdec & (1 << (m % 99)):
return False # e.g. 17, 68
if 0x6fd1bfcfed5f3679d3ebdec & (1 << (m % 91)):
return False # e.g. 97, 388
if 0xdef9ae771ffe3b9d67dec & (1 << (m % 85)):
return False # e.g. 793, 1408
return mlib.sqrtrem(int(x))[1] == 0
def invert(x, m):
"""Modular inverse of x modulo m.
Returns y such that x*y == 1 mod m.
Uses ``math.pow`` but reproduces the behaviour of ``gmpy2.invert``
which raises ZeroDivisionError if no inverse exists.
"""
try:
return pow(x, -1, m)
except ValueError:
raise ZeroDivisionError("invert() no inverse exists")
def legendre(x, y):
"""Legendre symbol (x / y).
Following the implementation of gmpy2,
the error is raised only when y is an even number.
"""
if y <= 0 or not y % 2:
raise ValueError("y should be an odd prime")
x %= y
if not x:
return 0
if pow(x, (y - 1) // 2, y) == 1:
return 1
return -1
def jacobi(x, y):
"""Jacobi symbol (x / y)."""
if y <= 0 or not y % 2:
raise ValueError("y should be an odd positive integer")
x %= y
if not x:
return int(y == 1)
if y == 1 or x == 1:
return 1
if gcd(x, y) != 1:
return 0
j = 1
while x != 0:
while x % 2 == 0 and x > 0:
x >>= 1
if y % 8 in [3, 5]:
j = -j
x, y = y, x
if x % 4 == y % 4 == 3:
j = -j
x %= y
return j
def kronecker(x, y):
"""Kronecker symbol (x / y)."""
if gcd(x, y) != 1:
return 0
if y == 0:
return 1
sign = -1 if y < 0 and x < 0 else 1
y = abs(y)
s = bit_scan1(y)
y >>= s
if s % 2 and x % 8 in [3, 5]:
sign = -sign
return sign * jacobi(x, y)
def iroot(y, n):
if y < 0:
raise ValueError("y must be nonnegative")
if n < 1:
raise ValueError("n must be positive")
if y in (0, 1):
return y, True
if n == 1:
return y, True
if n == 2:
x, rem = mlib.sqrtrem(y)
return int(x), not rem
if n >= y.bit_length():
return 1, False
# Get initial estimate for Newton's method. Care must be taken to
# avoid overflow
try:
guess = int(y**(1./n) + 0.5)
except OverflowError:
exp = math.log2(y)/n
if exp > 53:
shift = int(exp - 53)
guess = int(2.0**(exp - shift) + 1) << shift
else:
guess = int(2.0**exp)
if guess > 2**50:
# Newton iteration
xprev, x = -1, guess
while 1:
t = x**(n - 1)
xprev, x = x, ((n - 1)*x + y//t)//n
if abs(x - xprev) < 2:
break
else:
x = guess
# Compensate
t = x**n
while t < y:
x += 1
t = x**n
while t > y:
x -= 1
t = x**n
return x, t == y
def is_fermat_prp(n, a):
if a < 2:
raise ValueError("is_fermat_prp() requires 'a' greater than or equal to 2")
if n < 1:
raise ValueError("is_fermat_prp() requires 'n' be greater than 0")
if n == 1:
return False
if n % 2 == 0:
return n == 2
a %= n
if gcd(n, a) != 1:
raise ValueError("is_fermat_prp() requires gcd(n,a) == 1")
return pow(a, n - 1, n) == 1
def is_euler_prp(n, a):
if a < 2:
raise ValueError("is_euler_prp() requires 'a' greater than or equal to 2")
if n < 1:
raise ValueError("is_euler_prp() requires 'n' be greater than 0")
if n == 1:
return False
if n % 2 == 0:
return n == 2
a %= n
if gcd(n, a) != 1:
raise ValueError("is_euler_prp() requires gcd(n,a) == 1")
return pow(a, n >> 1, n) == jacobi(a, n) % n
def _is_strong_prp(n, a):
s = bit_scan1(n - 1)
a = pow(a, n >> s, n)
if a == 1 or a == n - 1:
return True
for _ in range(s - 1):
a = pow(a, 2, n)
if a == n - 1:
return True
if a == 1:
return False
return False
def is_strong_prp(n, a):
if a < 2:
raise ValueError("is_strong_prp() requires 'a' greater than or equal to 2")
if n < 1:
raise ValueError("is_strong_prp() requires 'n' be greater than 0")
if n == 1:
return False
if n % 2 == 0:
return n == 2
a %= n
if gcd(n, a) != 1:
raise ValueError("is_strong_prp() requires gcd(n,a) == 1")
return _is_strong_prp(n, a)
def _lucas_sequence(n, P, Q, k):
r"""Return the modular Lucas sequence (U_k, V_k, Q_k).
Explanation
===========
Given a Lucas sequence defined by P, Q, returns the kth values for
U and V, along with Q^k, all modulo n. This is intended for use with
possibly very large values of n and k, where the combinatorial functions
would be completely unusable.
.. math ::
U_k = \begin{cases}
0 & \text{if } k = 0\\
1 & \text{if } k = 1\\
PU_{k-1} - QU_{k-2} & \text{if } k > 1
\end{cases}\\
V_k = \begin{cases}
2 & \text{if } k = 0\\
P & \text{if } k = 1\\
PV_{k-1} - QV_{k-2} & \text{if } k > 1
\end{cases}
The modular Lucas sequences are used in numerous places in number theory,
especially in the Lucas compositeness tests and the various n + 1 proofs.
Parameters
==========
n : int
n is an odd number greater than or equal to 3
P : int
Q : int
D determined by D = P**2 - 4*Q is non-zero
k : int
k is a nonnegative integer
Returns
=======
U, V, Qk : (int, int, int)
`(U_k \bmod{n}, V_k \bmod{n}, Q^k \bmod{n})`
Examples
========
>>> from sympy.external.ntheory import _lucas_sequence
>>> N = 10**2000 + 4561
>>> sol = U, V, Qk = _lucas_sequence(N, 3, 1, N//2); sol
(0, 2, 1)
References
==========
.. [1] https://en.wikipedia.org/wiki/Lucas_sequence
"""
if k == 0:
return (0, 2, 1)
D = P**2 - 4*Q
U = 1
V = P
Qk = Q % n
if Q == 1:
# Optimization for extra strong tests.
for b in bin(k)[3:]:
U = (U*V) % n
V = (V*V - 2) % n
if b == "1":
U, V = U*P + V, V*P + U*D
if U & 1:
U += n
if V & 1:
V += n
U, V = U >> 1, V >> 1
elif P == 1 and Q == -1:
# Small optimization for 50% of Selfridge parameters.
for b in bin(k)[3:]:
U = (U*V) % n
if Qk == 1:
V = (V*V - 2) % n
else:
V = (V*V + 2) % n
Qk = 1
if b == "1":
# new_U = (U + V) // 2
# new_V = (5*U + V) // 2 = 2*U + new_U
U, V = U + V, U << 1
if U & 1:
U += n
U >>= 1
V += U
Qk = -1
Qk %= n
elif P == 1:
for b in bin(k)[3:]:
U = (U*V) % n
V = (V*V - 2*Qk) % n
Qk *= Qk
if b == "1":
# new_U = (U + V) // 2
# new_V = new_U - 2*Q*U
U, V = U + V, (Q*U) << 1
if U & 1:
U += n
U >>= 1
V = U - V
Qk *= Q
Qk %= n
else:
# The general case with any P and Q.
for b in bin(k)[3:]:
U = (U*V) % n
V = (V*V - 2*Qk) % n
Qk *= Qk
if b == "1":
U, V = U*P + V, V*P + U*D
if U & 1:
U += n
if V & 1:
V += n
U, V = U >> 1, V >> 1
Qk *= Q
Qk %= n
return (U % n, V % n, Qk)
def is_fibonacci_prp(n, p, q):
d = p**2 - 4*q
if d == 0 or p <= 0 or q not in [1, -1]:
raise ValueError("invalid values for p,q in is_fibonacci_prp()")
if n < 1:
raise ValueError("is_fibonacci_prp() requires 'n' be greater than 0")
if n == 1:
return False
if n % 2 == 0:
return n == 2
return _lucas_sequence(n, p, q, n)[1] == p % n
def is_lucas_prp(n, p, q):
d = p**2 - 4*q
if d == 0:
raise ValueError("invalid values for p,q in is_lucas_prp()")
if n < 1:
raise ValueError("is_lucas_prp() requires 'n' be greater than 0")
if n == 1:
return False
if n % 2 == 0:
return n == 2
if gcd(n, q*d) not in [1, n]:
raise ValueError("is_lucas_prp() requires gcd(n,2*q*D) == 1")
return _lucas_sequence(n, p, q, n - jacobi(d, n))[0] == 0
def _is_selfridge_prp(n):
"""Lucas compositeness test with the Selfridge parameters for n.
Explanation
===========
The Lucas compositeness test checks whether n is a prime number.
The test can be run with arbitrary parameters ``P`` and ``Q``, which also change the performance of the test.
So, which parameters are most effective for running the Lucas compositeness test?
As an algorithm for determining ``P`` and ``Q``, Selfridge proposed method A [1]_ page 1401
(Since two methods were proposed, referred to simply as A and B in the paper,
we will refer to one of them as "method A").
method A fixes ``P = 1``. Then, ``D`` defined by ``D = P**2 - 4Q`` is varied from 5, -7, 9, -11, 13, and so on,
with the first ``D`` being ``jacobi(D, n) == -1``. Once ``D`` is determined,
``Q`` is determined to be ``(P**2 - D)//4``.
References
==========
.. [1] Robert Baillie, Samuel S. Wagstaff, Lucas Pseudoprimes,
Math. Comp. Vol 35, Number 152 (1980), pp. 1391-1417,
https://doi.org/10.1090%2FS0025-5718-1980-0583518-6
http://mpqs.free.fr/LucasPseudoprimes.pdf
"""
for D in range(5, 1_000_000, 2):
if D & 2: # if D % 4 == 3
D = -D
j = jacobi(D, n)
if j == -1:
return _lucas_sequence(n, 1, (1-D) // 4, n + 1)[0] == 0
if j == 0 and D % n:
return False
# When j == -1 is hard to find, suspect a square number
if D == 13 and is_square(n):
return False
raise ValueError("appropriate value for D cannot be found in is_selfridge_prp()")
def is_selfridge_prp(n):
if n < 1:
raise ValueError("is_selfridge_prp() requires 'n' be greater than 0")
if n == 1:
return False
if n % 2 == 0:
return n == 2
return _is_selfridge_prp(n)
def is_strong_lucas_prp(n, p, q):
D = p**2 - 4*q
if D == 0:
raise ValueError("invalid values for p,q in is_strong_lucas_prp()")
if n < 1:
raise ValueError("is_selfridge_prp() requires 'n' be greater than 0")
if n == 1:
return False
if n % 2 == 0:
return n == 2
if gcd(n, q*D) not in [1, n]:
raise ValueError("is_strong_lucas_prp() requires gcd(n,2*q*D) == 1")
j = jacobi(D, n)
s = bit_scan1(n - j)
U, V, Qk = _lucas_sequence(n, p, q, (n - j) >> s)
if U == 0 or V == 0:
return True
for _ in range(s - 1):
V = (V*V - 2*Qk) % n
if V == 0:
return True
Qk = pow(Qk, 2, n)
return False
def _is_strong_selfridge_prp(n):
for D in range(5, 1_000_000, 2):
if D & 2: # if D % 4 == 3
D = -D
j = jacobi(D, n)
if j == -1:
s = bit_scan1(n + 1)
U, V, Qk = _lucas_sequence(n, 1, (1-D) // 4, (n + 1) >> s)
if U == 0 or V == 0:
return True
for _ in range(s - 1):
V = (V*V - 2*Qk) % n
if V == 0:
return True
Qk = pow(Qk, 2, n)
return False
if j == 0 and D % n:
return False
# When j == -1 is hard to find, suspect a square number
if D == 13 and is_square(n):
return False
raise ValueError("appropriate value for D cannot be found in is_strong_selfridge_prp()")
def is_strong_selfridge_prp(n):
if n < 1:
raise ValueError("is_strong_selfridge_prp() requires 'n' be greater than 0")
if n == 1:
return False
if n % 2 == 0:
return n == 2
return _is_strong_selfridge_prp(n)
def is_bpsw_prp(n):
if n < 1:
raise ValueError("is_bpsw_prp() requires 'n' be greater than 0")
if n == 1:
return False
if n % 2 == 0:
return n == 2
return _is_strong_prp(n, 2) and _is_selfridge_prp(n)
def is_strong_bpsw_prp(n):
if n < 1:
raise ValueError("is_strong_bpsw_prp() requires 'n' be greater than 0")
if n == 1:
return False
if n % 2 == 0:
return n == 2
return _is_strong_prp(n, 2) and _is_strong_selfridge_prp(n)
PK ]ZZZ����+ �+ sympy/external/pythonmpq.py"""
PythonMPQ: Rational number type based on Python integers.
This class is intended as a pure Python fallback for when gmpy2 is not
installed. If gmpy2 is installed then its mpq type will be used instead. The
mpq type is around 20x faster. We could just use the stdlib Fraction class
here but that is slower:
from fractions import Fraction
from sympy.external.pythonmpq import PythonMPQ
nums = range(1000)
dens = range(5, 1005)
rats = [Fraction(n, d) for n, d in zip(nums, dens)]
sum(rats) # <--- 24 milliseconds
rats = [PythonMPQ(n, d) for n, d in zip(nums, dens)]
sum(rats) # <--- 7 milliseconds
Both mpq and Fraction have some awkward features like the behaviour of
division with // and %:
>>> from fractions import Fraction
>>> Fraction(2, 3) % Fraction(1, 4)
1/6
For the QQ domain we do not want this behaviour because there should be no
remainder when dividing rational numbers. SymPy does not make use of this
aspect of mpq when gmpy2 is installed. Since this class is a fallback for that
case we do not bother implementing e.g. __mod__ so that we can be sure we
are not using it when gmpy2 is installed either.
"""
import operator
from math import gcd
from decimal import Decimal
from fractions import Fraction
import sys
from typing import Tuple as tTuple, Type
# Used for __hash__
_PyHASH_MODULUS = sys.hash_info.modulus
_PyHASH_INF = sys.hash_info.inf
class PythonMPQ:
"""Rational number implementation that is intended to be compatible with
gmpy2's mpq.
Also slightly faster than fractions.Fraction.
PythonMPQ should be treated as immutable although no effort is made to
prevent mutation (since that might slow down calculations).
"""
__slots__ = ('numerator', 'denominator')
def __new__(cls, numerator, denominator=None):
"""Construct PythonMPQ with gcd computation and checks"""
if denominator is not None:
#
# PythonMPQ(n, d): require n and d to be int and d != 0
#
if isinstance(numerator, int) and isinstance(denominator, int):
# This is the slow part:
divisor = gcd(numerator, denominator)
numerator //= divisor
denominator //= divisor
return cls._new_check(numerator, denominator)
else:
#
# PythonMPQ(q)
#
# Here q can be PythonMPQ, int, Decimal, float, Fraction or str
#
if isinstance(numerator, int):
return cls._new(numerator, 1)
elif isinstance(numerator, PythonMPQ):
return cls._new(numerator.numerator, numerator.denominator)
# Let Fraction handle Decimal/float conversion and str parsing
if isinstance(numerator, (Decimal, float, str)):
numerator = Fraction(numerator)
if isinstance(numerator, Fraction):
return cls._new(numerator.numerator, numerator.denominator)
#
# Reject everything else. This is more strict than mpq which allows
# things like mpq(Fraction, Fraction) or mpq(Decimal, any). The mpq
# behaviour is somewhat inconsistent so we choose to accept only a
# more strict subset of what mpq allows.
#
raise TypeError("PythonMPQ() requires numeric or string argument")
@classmethod
def _new_check(cls, numerator, denominator):
"""Construct PythonMPQ, check divide by zero and canonicalize signs"""
if not denominator:
raise ZeroDivisionError(f'Zero divisor {numerator}/{denominator}')
elif denominator < 0:
numerator = -numerator
denominator = -denominator
return cls._new(numerator, denominator)
@classmethod
def _new(cls, numerator, denominator):
"""Construct PythonMPQ efficiently (no checks)"""
obj = super().__new__(cls)
obj.numerator = numerator
obj.denominator = denominator
return obj
def __int__(self):
"""Convert to int (truncates towards zero)"""
p, q = self.numerator, self.denominator
if p < 0:
return -(-p//q)
return p//q
def __float__(self):
"""Convert to float (approximately)"""
return self.numerator / self.denominator
def __bool__(self):
"""True/False if nonzero/zero"""
return bool(self.numerator)
def __eq__(self, other):
"""Compare equal with PythonMPQ, int, float, Decimal or Fraction"""
if isinstance(other, PythonMPQ):
return (self.numerator == other.numerator
and self.denominator == other.denominator)
elif isinstance(other, self._compatible_types):
return self.__eq__(PythonMPQ(other))
else:
return NotImplemented
def __hash__(self):
"""hash - same as mpq/Fraction"""
try:
dinv = pow(self.denominator, -1, _PyHASH_MODULUS)
except ValueError:
hash_ = _PyHASH_INF
else:
hash_ = hash(hash(abs(self.numerator)) * dinv)
result = hash_ if self.numerator >= 0 else -hash_
return -2 if result == -1 else result
def __reduce__(self):
"""Deconstruct for pickling"""
return type(self), (self.numerator, self.denominator)
def __str__(self):
"""Convert to string"""
if self.denominator != 1:
return f"{self.numerator}/{self.denominator}"
else:
return f"{self.numerator}"
def __repr__(self):
"""Convert to string"""
return f"MPQ({self.numerator},{self.denominator})"
def _cmp(self, other, op):
"""Helper for lt/le/gt/ge"""
if not isinstance(other, self._compatible_types):
return NotImplemented
lhs = self.numerator * other.denominator
rhs = other.numerator * self.denominator
return op(lhs, rhs)
def __lt__(self, other):
"""self < other"""
return self._cmp(other, operator.lt)
def __le__(self, other):
"""self <= other"""
return self._cmp(other, operator.le)
def __gt__(self, other):
"""self > other"""
return self._cmp(other, operator.gt)
def __ge__(self, other):
"""self >= other"""
return self._cmp(other, operator.ge)
def __abs__(self):
"""abs(q)"""
return self._new(abs(self.numerator), self.denominator)
def __pos__(self):
"""+q"""
return self
def __neg__(self):
"""-q"""
return self._new(-self.numerator, self.denominator)
def __add__(self, other):
"""q1 + q2"""
if isinstance(other, PythonMPQ):
#
# This is much faster than the naive method used in the stdlib
# fractions module. Not sure where this method comes from
# though...
#
# Compare timings for something like:
# nums = range(1000)
# rats = [PythonMPQ(n, d) for n, d in zip(nums[:-5], nums[5:])]
# sum(rats) # <-- time this
#
ap, aq = self.numerator, self.denominator
bp, bq = other.numerator, other.denominator
g = gcd(aq, bq)
if g == 1:
p = ap*bq + aq*bp
q = bq*aq
else:
q1, q2 = aq//g, bq//g
p, q = ap*q2 + bp*q1, q1*q2
g2 = gcd(p, g)
p, q = (p // g2), q * (g // g2)
elif isinstance(other, int):
p = self.numerator + self.denominator * other
q = self.denominator
else:
return NotImplemented
return self._new(p, q)
def __radd__(self, other):
"""z1 + q2"""
if isinstance(other, int):
p = self.numerator + self.denominator * other
q = self.denominator
return self._new(p, q)
else:
return NotImplemented
def __sub__(self ,other):
"""q1 - q2"""
if isinstance(other, PythonMPQ):
ap, aq = self.numerator, self.denominator
bp, bq = other.numerator, other.denominator
g = gcd(aq, bq)
if g == 1:
p = ap*bq - aq*bp
q = bq*aq
else:
q1, q2 = aq//g, bq//g
p, q = ap*q2 - bp*q1, q1*q2
g2 = gcd(p, g)
p, q = (p // g2), q * (g // g2)
elif isinstance(other, int):
p = self.numerator - self.denominator*other
q = self.denominator
else:
return NotImplemented
return self._new(p, q)
def __rsub__(self, other):
"""z1 - q2"""
if isinstance(other, int):
p = self.denominator * other - self.numerator
q = self.denominator
return self._new(p, q)
else:
return NotImplemented
def __mul__(self, other):
"""q1 * q2"""
if isinstance(other, PythonMPQ):
ap, aq = self.numerator, self.denominator
bp, bq = other.numerator, other.denominator
x1 = gcd(ap, bq)
x2 = gcd(bp, aq)
p, q = ((ap//x1)*(bp//x2), (aq//x2)*(bq//x1))
elif isinstance(other, int):
x = gcd(other, self.denominator)
p = self.numerator*(other//x)
q = self.denominator//x
else:
return NotImplemented
return self._new(p, q)
def __rmul__(self, other):
"""z1 * q2"""
if isinstance(other, int):
x = gcd(self.denominator, other)
p = self.numerator*(other//x)
q = self.denominator//x
return self._new(p, q)
else:
return NotImplemented
def __pow__(self, exp):
"""q ** z"""
p, q = self.numerator, self.denominator
if exp < 0:
p, q, exp = q, p, -exp
return self._new_check(p**exp, q**exp)
def __truediv__(self, other):
"""q1 / q2"""
if isinstance(other, PythonMPQ):
ap, aq = self.numerator, self.denominator
bp, bq = other.numerator, other.denominator
x1 = gcd(ap, bp)
x2 = gcd(bq, aq)
p, q = ((ap//x1)*(bq//x2), (aq//x2)*(bp//x1))
elif isinstance(other, int):
x = gcd(other, self.numerator)
p = self.numerator//x
q = self.denominator*(other//x)
else:
return NotImplemented
return self._new_check(p, q)
def __rtruediv__(self, other):
"""z / q"""
if isinstance(other, int):
x = gcd(self.numerator, other)
p = self.denominator*(other//x)
q = self.numerator//x
return self._new_check(p, q)
else:
return NotImplemented
_compatible_types: tTuple[Type, ...] = ()
#
# These are the types that PythonMPQ will interoperate with for operations
# and comparisons such as ==, + etc. We define this down here so that we can
# include PythonMPQ in the list as well.
#
PythonMPQ._compatible_types = (PythonMPQ, int, Decimal, Fraction)
PK ]ZZZ� �Ľ � sympy/functions/__init__.py"""A functions module, includes all the standard functions.
Combinatorial - factorial, fibonacci, harmonic, bernoulli...
Elementary - hyperbolic, trigonometric, exponential, floor and ceiling, sqrt...
Special - gamma, zeta,spherical harmonics...
"""
from sympy.functions.combinatorial.factorials import (factorial, factorial2,
rf, ff, binomial, RisingFactorial, FallingFactorial, subfactorial)
from sympy.functions.combinatorial.numbers import (carmichael, fibonacci, lucas, tribonacci,
harmonic, bernoulli, bell, euler, catalan, genocchi, andre, partition, divisor_sigma,
udivisor_sigma, legendre_symbol, jacobi_symbol, kronecker_symbol, mobius,
primenu, primeomega, totient, reduced_totient, primepi, motzkin)
from sympy.functions.elementary.miscellaneous import (sqrt, root, Min, Max,
Id, real_root, cbrt, Rem)
from sympy.functions.elementary.complexes import (re, im, sign, Abs,
conjugate, arg, polar_lift, periodic_argument, unbranched_argument,
principal_branch, transpose, adjoint, polarify, unpolarify)
from sympy.functions.elementary.trigonometric import (sin, cos, tan,
sec, csc, cot, sinc, asin, acos, atan, asec, acsc, acot, atan2)
from sympy.functions.elementary.exponential import (exp_polar, exp, log,
LambertW)
from sympy.functions.elementary.hyperbolic import (sinh, cosh, tanh, coth,
sech, csch, asinh, acosh, atanh, acoth, asech, acsch)
from sympy.functions.elementary.integers import floor, ceiling, frac
from sympy.functions.elementary.piecewise import (Piecewise, piecewise_fold,
piecewise_exclusive)
from sympy.functions.special.error_functions import (erf, erfc, erfi, erf2,
erfinv, erfcinv, erf2inv, Ei, expint, E1, li, Li, Si, Ci, Shi, Chi,
fresnels, fresnelc)
from sympy.functions.special.gamma_functions import (gamma, lowergamma,
uppergamma, polygamma, loggamma, digamma, trigamma, multigamma)
from sympy.functions.special.zeta_functions import (dirichlet_eta, zeta,
lerchphi, polylog, stieltjes, riemann_xi)
from sympy.functions.special.tensor_functions import (Eijk, LeviCivita,
KroneckerDelta)
from sympy.functions.special.singularity_functions import SingularityFunction
from sympy.functions.special.delta_functions import DiracDelta, Heaviside
from sympy.functions.special.bsplines import bspline_basis, bspline_basis_set, interpolating_spline
from sympy.functions.special.bessel import (besselj, bessely, besseli, besselk,
hankel1, hankel2, jn, yn, jn_zeros, hn1, hn2, airyai, airybi, airyaiprime, airybiprime, marcumq)
from sympy.functions.special.hyper import hyper, meijerg, appellf1
from sympy.functions.special.polynomials import (legendre, assoc_legendre,
hermite, hermite_prob, chebyshevt, chebyshevu, chebyshevu_root,
chebyshevt_root, laguerre, assoc_laguerre, gegenbauer, jacobi, jacobi_normalized)
from sympy.functions.special.spherical_harmonics import Ynm, Ynm_c, Znm
from sympy.functions.special.elliptic_integrals import (elliptic_k,
elliptic_f, elliptic_e, elliptic_pi)
from sympy.functions.special.beta_functions import beta, betainc, betainc_regularized
from sympy.functions.special.mathieu_functions import (mathieus, mathieuc,
mathieusprime, mathieucprime)
ln = log
__all__ = [
'factorial', 'factorial2', 'rf', 'ff', 'binomial', 'RisingFactorial',
'FallingFactorial', 'subfactorial',
'carmichael', 'fibonacci', 'lucas', 'motzkin', 'tribonacci', 'harmonic',
'bernoulli', 'bell', 'euler', 'catalan', 'genocchi', 'andre', 'partition',
'divisor_sigma', 'udivisor_sigma', 'legendre_symbol', 'jacobi_symbol', 'kronecker_symbol',
'mobius', 'primenu', 'primeomega', 'totient', 'reduced_totient', 'primepi',
'sqrt', 'root', 'Min', 'Max', 'Id', 'real_root', 'cbrt', 'Rem',
're', 'im', 'sign', 'Abs', 'conjugate', 'arg', 'polar_lift',
'periodic_argument', 'unbranched_argument', 'principal_branch',
'transpose', 'adjoint', 'polarify', 'unpolarify',
'sin', 'cos', 'tan', 'sec', 'csc', 'cot', 'sinc', 'asin', 'acos', 'atan',
'asec', 'acsc', 'acot', 'atan2',
'exp_polar', 'exp', 'ln', 'log', 'LambertW',
'sinh', 'cosh', 'tanh', 'coth', 'sech', 'csch', 'asinh', 'acosh', 'atanh',
'acoth', 'asech', 'acsch',
'floor', 'ceiling', 'frac',
'Piecewise', 'piecewise_fold', 'piecewise_exclusive',
'erf', 'erfc', 'erfi', 'erf2', 'erfinv', 'erfcinv', 'erf2inv', 'Ei',
'expint', 'E1', 'li', 'Li', 'Si', 'Ci', 'Shi', 'Chi', 'fresnels',
'fresnelc',
'gamma', 'lowergamma', 'uppergamma', 'polygamma', 'loggamma', 'digamma',
'trigamma', 'multigamma',
'dirichlet_eta', 'zeta', 'lerchphi', 'polylog', 'stieltjes', 'riemann_xi',
'Eijk', 'LeviCivita', 'KroneckerDelta',
'SingularityFunction',
'DiracDelta', 'Heaviside',
'bspline_basis', 'bspline_basis_set', 'interpolating_spline',
'besselj', 'bessely', 'besseli', 'besselk', 'hankel1', 'hankel2', 'jn',
'yn', 'jn_zeros', 'hn1', 'hn2', 'airyai', 'airybi', 'airyaiprime',
'airybiprime', 'marcumq',
'hyper', 'meijerg', 'appellf1',
'legendre', 'assoc_legendre', 'hermite', 'hermite_prob', 'chebyshevt',
'chebyshevu', 'chebyshevu_root', 'chebyshevt_root', 'laguerre',
'assoc_laguerre', 'gegenbauer', 'jacobi', 'jacobi_normalized',
'Ynm', 'Ynm_c', 'Znm',
'elliptic_k', 'elliptic_f', 'elliptic_e', 'elliptic_pi',
'beta', 'betainc', 'betainc_regularized',
'mathieus', 'mathieuc', 'mathieusprime', 'mathieucprime',
]
PK ]ZZZ@��d5 5 ) sympy/functions/combinatorial/__init__.py# Stub __init__.py for sympy.functions.combinatorial
PK ]ZZZY�E� � + sympy/functions/combinatorial/factorials.pyfrom __future__ import annotations
from functools import reduce
from sympy.core import S, sympify, Dummy, Mod
from sympy.core.cache import cacheit
from sympy.core.function import Function, ArgumentIndexError, PoleError
from sympy.core.logic import fuzzy_and
from sympy.core.numbers import Integer, pi, I
from sympy.core.relational import Eq
from sympy.external.gmpy import gmpy as _gmpy
from sympy.ntheory import sieve
from sympy.ntheory.residue_ntheory import binomial_mod
from sympy.polys.polytools import Poly
from math import factorial as _factorial, prod, sqrt as _sqrt
class CombinatorialFunction(Function):
"""Base class for combinatorial functions. """
def _eval_simplify(self, **kwargs):
from sympy.simplify.combsimp import combsimp
# combinatorial function with non-integer arguments is
# automatically passed to gammasimp
expr = combsimp(self)
measure = kwargs['measure']
if measure(expr) <= kwargs['ratio']*measure(self):
return expr
return self
###############################################################################
######################## FACTORIAL and MULTI-FACTORIAL ########################
###############################################################################
class factorial(CombinatorialFunction):
r"""Implementation of factorial function over nonnegative integers.
By convention (consistent with the gamma function and the binomial
coefficients), factorial of a negative integer is complex infinity.
The factorial is very important in combinatorics where it gives
the number of ways in which `n` objects can be permuted. It also
arises in calculus, probability, number theory, etc.
There is strict relation of factorial with gamma function. In
fact `n! = gamma(n+1)` for nonnegative integers. Rewrite of this
kind is very useful in case of combinatorial simplification.
Computation of the factorial is done using two algorithms. For
small arguments a precomputed look up table is used. However for bigger
input algorithm Prime-Swing is used. It is the fastest algorithm
known and computes `n!` via prime factorization of special class
of numbers, called here the 'Swing Numbers'.
Examples
========
>>> from sympy import Symbol, factorial, S
>>> n = Symbol('n', integer=True)
>>> factorial(0)
1
>>> factorial(7)
5040
>>> factorial(-2)
zoo
>>> factorial(n)
factorial(n)
>>> factorial(2*n)
factorial(2*n)
>>> factorial(S(1)/2)
factorial(1/2)
See Also
========
factorial2, RisingFactorial, FallingFactorial
"""
def fdiff(self, argindex=1):
from sympy.functions.special.gamma_functions import (gamma, polygamma)
if argindex == 1:
return gamma(self.args[0] + 1)*polygamma(0, self.args[0] + 1)
else:
raise ArgumentIndexError(self, argindex)
_small_swing = [
1, 1, 1, 3, 3, 15, 5, 35, 35, 315, 63, 693, 231, 3003, 429, 6435, 6435, 109395,
12155, 230945, 46189, 969969, 88179, 2028117, 676039, 16900975, 1300075,
35102025, 5014575, 145422675, 9694845, 300540195, 300540195
]
_small_factorials: list[int] = []
@classmethod
def _swing(cls, n):
if n < 33:
return cls._small_swing[n]
else:
N, primes = int(_sqrt(n)), []
for prime in sieve.primerange(3, N + 1):
p, q = 1, n
while True:
q //= prime
if q > 0:
if q & 1 == 1:
p *= prime
else:
break
if p > 1:
primes.append(p)
for prime in sieve.primerange(N + 1, n//3 + 1):
if (n // prime) & 1 == 1:
primes.append(prime)
L_product = prod(sieve.primerange(n//2 + 1, n + 1))
R_product = prod(primes)
return L_product*R_product
@classmethod
def _recursive(cls, n):
if n < 2:
return 1
else:
return (cls._recursive(n//2)**2)*cls._swing(n)
@classmethod
def eval(cls, n):
n = sympify(n)
if n.is_Number:
if n.is_zero:
return S.One
elif n is S.Infinity:
return S.Infinity
elif n.is_Integer:
if n.is_negative:
return S.ComplexInfinity
else:
n = n.p
if n < 20:
if not cls._small_factorials:
result = 1
for i in range(1, 20):
result *= i
cls._small_factorials.append(result)
result = cls._small_factorials[n-1]
# GMPY factorial is faster, use it when available
#
# XXX: There is a sympy.external.gmpy.factorial function
# which provides gmpy.fac if available or the flint version
# if flint is used. It could be used here to avoid the
# conditional logic but it needs to be checked whether the
# pure Python fallback used there is as fast as the
# fallback used here (perhaps the fallback here should be
# moved to sympy.external.ntheory).
elif _gmpy is not None:
result = _gmpy.fac(n)
else:
bits = bin(n).count('1')
result = cls._recursive(n)*2**(n - bits)
return Integer(result)
def _facmod(self, n, q):
res, N = 1, int(_sqrt(n))
# Exponent of prime p in n! is e_p(n) = [n/p] + [n/p**2] + ...
# for p > sqrt(n), e_p(n) < sqrt(n), the primes with [n/p] = m,
# occur consecutively and are grouped together in pw[m] for
# simultaneous exponentiation at a later stage
pw = [1]*N
m = 2 # to initialize the if condition below
for prime in sieve.primerange(2, n + 1):
if m > 1:
m, y = 0, n // prime
while y:
m += y
y //= prime
if m < N:
pw[m] = pw[m]*prime % q
else:
res = res*pow(prime, m, q) % q
for ex, bs in enumerate(pw):
if ex == 0 or bs == 1:
continue
if bs == 0:
return 0
res = res*pow(bs, ex, q) % q
return res
def _eval_Mod(self, q):
n = self.args[0]
if n.is_integer and n.is_nonnegative and q.is_integer:
aq = abs(q)
d = aq - n
if d.is_nonpositive:
return S.Zero
else:
isprime = aq.is_prime
if d == 1:
# Apply Wilson's theorem (if a natural number n > 1
# is a prime number, then (n-1)! = -1 mod n) and
# its inverse (if n > 4 is a composite number, then
# (n-1)! = 0 mod n)
if isprime:
return -1 % q
elif isprime is False and (aq - 6).is_nonnegative:
return S.Zero
elif n.is_Integer and q.is_Integer:
n, d, aq = map(int, (n, d, aq))
if isprime and (d - 1 < n):
fc = self._facmod(d - 1, aq)
fc = pow(fc, aq - 2, aq)
if d%2:
fc = -fc
else:
fc = self._facmod(n, aq)
return fc % q
def _eval_rewrite_as_gamma(self, n, piecewise=True, **kwargs):
from sympy.functions.special.gamma_functions import gamma
return gamma(n + 1)
def _eval_rewrite_as_Product(self, n, **kwargs):
from sympy.concrete.products import Product
if n.is_nonnegative and n.is_integer:
i = Dummy('i', integer=True)
return Product(i, (i, 1, n))
def _eval_is_integer(self):
if self.args[0].is_integer and self.args[0].is_nonnegative:
return True
def _eval_is_positive(self):
if self.args[0].is_integer and self.args[0].is_nonnegative:
return True
def _eval_is_even(self):
x = self.args[0]
if x.is_integer and x.is_nonnegative:
return (x - 2).is_nonnegative
def _eval_is_composite(self):
x = self.args[0]
if x.is_integer and x.is_nonnegative:
return (x - 3).is_nonnegative
def _eval_is_real(self):
x = self.args[0]
if x.is_nonnegative or x.is_noninteger:
return True
def _eval_as_leading_term(self, x, logx=None, cdir=0):
arg = self.args[0].as_leading_term(x)
arg0 = arg.subs(x, 0)
if arg0.is_zero:
return S.One
elif not arg0.is_infinite:
return self.func(arg)
raise PoleError("Cannot expand %s around 0" % (self))
class MultiFactorial(CombinatorialFunction):
pass
class subfactorial(CombinatorialFunction):
r"""The subfactorial counts the derangements of $n$ items and is
defined for non-negative integers as:
.. math:: !n = \begin{cases} 1 & n = 0 \\ 0 & n = 1 \\
(n-1)(!(n-1) + !(n-2)) & n > 1 \end{cases}
It can also be written as ``int(round(n!/exp(1)))`` but the
recursive definition with caching is implemented for this function.
An interesting analytic expression is the following [2]_
.. math:: !x = \Gamma(x + 1, -1)/e
which is valid for non-negative integers `x`. The above formula
is not very useful in case of non-integers. `\Gamma(x + 1, -1)` is
single-valued only for integral arguments `x`, elsewhere on the positive
real axis it has an infinite number of branches none of which are real.
References
==========
.. [1] https://en.wikipedia.org/wiki/Subfactorial
.. [2] https://mathworld.wolfram.com/Subfactorial.html
Examples
========
>>> from sympy import subfactorial
>>> from sympy.abc import n
>>> subfactorial(n + 1)
subfactorial(n + 1)
>>> subfactorial(5)
44
See Also
========
factorial, uppergamma,
sympy.utilities.iterables.generate_derangements
"""
@classmethod
@cacheit
def _eval(self, n):
if not n:
return S.One
elif n == 1:
return S.Zero
else:
z1, z2 = 1, 0
for i in range(2, n + 1):
z1, z2 = z2, (i - 1)*(z2 + z1)
return z2
@classmethod
def eval(cls, arg):
if arg.is_Number:
if arg.is_Integer and arg.is_nonnegative:
return cls._eval(arg)
elif arg is S.NaN:
return S.NaN
elif arg is S.Infinity:
return S.Infinity
def _eval_is_even(self):
if self.args[0].is_odd and self.args[0].is_nonnegative:
return True
def _eval_is_integer(self):
if self.args[0].is_integer and self.args[0].is_nonnegative:
return True
def _eval_rewrite_as_factorial(self, arg, **kwargs):
from sympy.concrete.summations import summation
i = Dummy('i')
f = S.NegativeOne**i / factorial(i)
return factorial(arg) * summation(f, (i, 0, arg))
def _eval_rewrite_as_gamma(self, arg, piecewise=True, **kwargs):
from sympy.functions.elementary.exponential import exp
from sympy.functions.special.gamma_functions import (gamma, lowergamma)
return (S.NegativeOne**(arg + 1)*exp(-I*pi*arg)*lowergamma(arg + 1, -1)
+ gamma(arg + 1))*exp(-1)
def _eval_rewrite_as_uppergamma(self, arg, **kwargs):
from sympy.functions.special.gamma_functions import uppergamma
return uppergamma(arg + 1, -1)/S.Exp1
def _eval_is_nonnegative(self):
if self.args[0].is_integer and self.args[0].is_nonnegative:
return True
def _eval_is_odd(self):
if self.args[0].is_even and self.args[0].is_nonnegative:
return True
class factorial2(CombinatorialFunction):
r"""The double factorial `n!!`, not to be confused with `(n!)!`
The double factorial is defined for nonnegative integers and for odd
negative integers as:
.. math:: n!! = \begin{cases} 1 & n = 0 \\
n(n-2)(n-4) \cdots 1 & n\ \text{positive odd} \\
n(n-2)(n-4) \cdots 2 & n\ \text{positive even} \\
(n+2)!!/(n+2) & n\ \text{negative odd} \end{cases}
References
==========
.. [1] https://en.wikipedia.org/wiki/Double_factorial
Examples
========
>>> from sympy import factorial2, var
>>> n = var('n')
>>> n
n
>>> factorial2(n + 1)
factorial2(n + 1)
>>> factorial2(5)
15
>>> factorial2(-1)
1
>>> factorial2(-5)
1/3
See Also
========
factorial, RisingFactorial, FallingFactorial
"""
@classmethod
def eval(cls, arg):
# TODO: extend this to complex numbers?
if arg.is_Number:
if not arg.is_Integer:
raise ValueError("argument must be nonnegative integer "
"or negative odd integer")
# This implementation is faster than the recursive one
# It also avoids "maximum recursion depth exceeded" runtime error
if arg.is_nonnegative:
if arg.is_even:
k = arg / 2
return 2**k * factorial(k)
return factorial(arg) / factorial2(arg - 1)
if arg.is_odd:
return arg*(S.NegativeOne)**((1 - arg)/2) / factorial2(-arg)
raise ValueError("argument must be nonnegative integer "
"or negative odd integer")
def _eval_is_even(self):
# Double factorial is even for every positive even input
n = self.args[0]
if n.is_integer:
if n.is_odd:
return False
if n.is_even:
if n.is_positive:
return True
if n.is_zero:
return False
def _eval_is_integer(self):
# Double factorial is an integer for every nonnegative input, and for
# -1 and -3
n = self.args[0]
if n.is_integer:
if (n + 1).is_nonnegative:
return True
if n.is_odd:
return (n + 3).is_nonnegative
def _eval_is_odd(self):
# Double factorial is odd for every odd input not smaller than -3, and
# for 0
n = self.args[0]
if n.is_odd:
return (n + 3).is_nonnegative
if n.is_even:
if n.is_positive:
return False
if n.is_zero:
return True
def _eval_is_positive(self):
# Double factorial is positive for every nonnegative input, and for
# every odd negative input which is of the form -1-4k for an
# nonnegative integer k
n = self.args[0]
if n.is_integer:
if (n + 1).is_nonnegative:
return True
if n.is_odd:
return ((n + 1) / 2).is_even
def _eval_rewrite_as_gamma(self, n, piecewise=True, **kwargs):
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.elementary.piecewise import Piecewise
from sympy.functions.special.gamma_functions import gamma
return 2**(n/2)*gamma(n/2 + 1) * Piecewise((1, Eq(Mod(n, 2), 0)),
(sqrt(2/pi), Eq(Mod(n, 2), 1)))
###############################################################################
######################## RISING and FALLING FACTORIALS ########################
###############################################################################
class RisingFactorial(CombinatorialFunction):
r"""
Rising factorial (also called Pochhammer symbol [1]_) is a double valued
function arising in concrete mathematics, hypergeometric functions
and series expansions. It is defined by:
.. math:: \texttt{rf(y, k)} = (x)^k = x \cdot (x+1) \cdots (x+k-1)
where `x` can be arbitrary expression and `k` is an integer. For
more information check "Concrete mathematics" by Graham, pp. 66
or visit https://mathworld.wolfram.com/RisingFactorial.html page.
When `x` is a `~.Poly` instance of degree $\ge 1$ with a single variable,
`(x)^k = x(y) \cdot x(y+1) \cdots x(y+k-1)`, where `y` is the
variable of `x`. This is as described in [2]_.
Examples
========
>>> from sympy import rf, Poly
>>> from sympy.abc import x
>>> rf(x, 0)
1
>>> rf(1, 5)
120
>>> rf(x, 5) == x*(1 + x)*(2 + x)*(3 + x)*(4 + x)
True
>>> rf(Poly(x**3, x), 2)
Poly(x**6 + 3*x**5 + 3*x**4 + x**3, x, domain='ZZ')
Rewriting is complicated unless the relationship between
the arguments is known, but rising factorial can
be rewritten in terms of gamma, factorial, binomial,
and falling factorial.
>>> from sympy import Symbol, factorial, ff, binomial, gamma
>>> n = Symbol('n', integer=True, positive=True)
>>> R = rf(n, n + 2)
>>> for i in (rf, ff, factorial, binomial, gamma):
... R.rewrite(i)
...
RisingFactorial(n, n + 2)
FallingFactorial(2*n + 1, n + 2)
factorial(2*n + 1)/factorial(n - 1)
binomial(2*n + 1, n + 2)*factorial(n + 2)
gamma(2*n + 2)/gamma(n)
See Also
========
factorial, factorial2, FallingFactorial
References
==========
.. [1] https://en.wikipedia.org/wiki/Pochhammer_symbol
.. [2] Peter Paule, "Greatest Factorial Factorization and Symbolic
Summation", Journal of Symbolic Computation, vol. 20, pp. 235-268,
1995.
"""
@classmethod
def eval(cls, x, k):
x = sympify(x)
k = sympify(k)
if x is S.NaN or k is S.NaN:
return S.NaN
elif x is S.One:
return factorial(k)
elif k.is_Integer:
if k.is_zero:
return S.One
else:
if k.is_positive:
if x is S.Infinity:
return S.Infinity
elif x is S.NegativeInfinity:
if k.is_odd:
return S.NegativeInfinity
else:
return S.Infinity
else:
if isinstance(x, Poly):
gens = x.gens
if len(gens)!= 1:
raise ValueError("rf only defined for "
"polynomials on one generator")
else:
return reduce(lambda r, i:
r*(x.shift(i)),
range(int(k)), 1)
else:
return reduce(lambda r, i: r*(x + i),
range(int(k)), 1)
else:
if x is S.Infinity:
return S.Infinity
elif x is S.NegativeInfinity:
return S.Infinity
else:
if isinstance(x, Poly):
gens = x.gens
if len(gens)!= 1:
raise ValueError("rf only defined for "
"polynomials on one generator")
else:
return 1/reduce(lambda r, i:
r*(x.shift(-i)),
range(1, abs(int(k)) + 1), 1)
else:
return 1/reduce(lambda r, i:
r*(x - i),
range(1, abs(int(k)) + 1), 1)
if k.is_integer == False:
if x.is_integer and x.is_negative:
return S.Zero
def _eval_rewrite_as_gamma(self, x, k, piecewise=True, **kwargs):
from sympy.functions.elementary.piecewise import Piecewise
from sympy.functions.special.gamma_functions import gamma
if not piecewise:
if (x <= 0) == True:
return S.NegativeOne**k*gamma(1 - x) / gamma(-k - x + 1)
return gamma(x + k) / gamma(x)
return Piecewise(
(gamma(x + k) / gamma(x), x > 0),
(S.NegativeOne**k*gamma(1 - x) / gamma(-k - x + 1), True))
def _eval_rewrite_as_FallingFactorial(self, x, k, **kwargs):
return FallingFactorial(x + k - 1, k)
def _eval_rewrite_as_factorial(self, x, k, **kwargs):
from sympy.functions.elementary.piecewise import Piecewise
if x.is_integer and k.is_integer:
return Piecewise(
(factorial(k + x - 1)/factorial(x - 1), x > 0),
(S.NegativeOne**k*factorial(-x)/factorial(-k - x), True))
def _eval_rewrite_as_binomial(self, x, k, **kwargs):
if k.is_integer:
return factorial(k) * binomial(x + k - 1, k)
def _eval_rewrite_as_tractable(self, x, k, limitvar=None, **kwargs):
from sympy.functions.special.gamma_functions import gamma
if limitvar:
k_lim = k.subs(limitvar, S.Infinity)
if k_lim is S.Infinity:
return (gamma(x + k).rewrite('tractable', deep=True) / gamma(x))
elif k_lim is S.NegativeInfinity:
return (S.NegativeOne**k*gamma(1 - x) / gamma(-k - x + 1).rewrite('tractable', deep=True))
return self.rewrite(gamma).rewrite('tractable', deep=True)
def _eval_is_integer(self):
return fuzzy_and((self.args[0].is_integer, self.args[1].is_integer,
self.args[1].is_nonnegative))
class FallingFactorial(CombinatorialFunction):
r"""
Falling factorial (related to rising factorial) is a double valued
function arising in concrete mathematics, hypergeometric functions
and series expansions. It is defined by
.. math:: \texttt{ff(x, k)} = (x)_k = x \cdot (x-1) \cdots (x-k+1)
where `x` can be arbitrary expression and `k` is an integer. For
more information check "Concrete mathematics" by Graham, pp. 66
or [1]_.
When `x` is a `~.Poly` instance of degree $\ge 1$ with single variable,
`(x)_k = x(y) \cdot x(y-1) \cdots x(y-k+1)`, where `y` is the
variable of `x`. This is as described in
>>> from sympy import ff, Poly, Symbol
>>> from sympy.abc import x
>>> n = Symbol('n', integer=True)
>>> ff(x, 0)
1
>>> ff(5, 5)
120
>>> ff(x, 5) == x*(x - 1)*(x - 2)*(x - 3)*(x - 4)
True
>>> ff(Poly(x**2, x), 2)
Poly(x**4 - 2*x**3 + x**2, x, domain='ZZ')
>>> ff(n, n)
factorial(n)
Rewriting is complicated unless the relationship between
the arguments is known, but falling factorial can
be rewritten in terms of gamma, factorial and binomial
and rising factorial.
>>> from sympy import factorial, rf, gamma, binomial, Symbol
>>> n = Symbol('n', integer=True, positive=True)
>>> F = ff(n, n - 2)
>>> for i in (rf, ff, factorial, binomial, gamma):
... F.rewrite(i)
...
RisingFactorial(3, n - 2)
FallingFactorial(n, n - 2)
factorial(n)/2
binomial(n, n - 2)*factorial(n - 2)
gamma(n + 1)/2
See Also
========
factorial, factorial2, RisingFactorial
References
==========
.. [1] https://mathworld.wolfram.com/FallingFactorial.html
.. [2] Peter Paule, "Greatest Factorial Factorization and Symbolic
Summation", Journal of Symbolic Computation, vol. 20, pp. 235-268,
1995.
"""
@classmethod
def eval(cls, x, k):
x = sympify(x)
k = sympify(k)
if x is S.NaN or k is S.NaN:
return S.NaN
elif k.is_integer and x == k:
return factorial(x)
elif k.is_Integer:
if k.is_zero:
return S.One
else:
if k.is_positive:
if x is S.Infinity:
return S.Infinity
elif x is S.NegativeInfinity:
if k.is_odd:
return S.NegativeInfinity
else:
return S.Infinity
else:
if isinstance(x, Poly):
gens = x.gens
if len(gens)!= 1:
raise ValueError("ff only defined for "
"polynomials on one generator")
else:
return reduce(lambda r, i:
r*(x.shift(-i)),
range(int(k)), 1)
else:
return reduce(lambda r, i: r*(x - i),
range(int(k)), 1)
else:
if x is S.Infinity:
return S.Infinity
elif x is S.NegativeInfinity:
return S.Infinity
else:
if isinstance(x, Poly):
gens = x.gens
if len(gens)!= 1:
raise ValueError("rf only defined for "
"polynomials on one generator")
else:
return 1/reduce(lambda r, i:
r*(x.shift(i)),
range(1, abs(int(k)) + 1), 1)
else:
return 1/reduce(lambda r, i: r*(x + i),
range(1, abs(int(k)) + 1), 1)
def _eval_rewrite_as_gamma(self, x, k, piecewise=True, **kwargs):
from sympy.functions.elementary.piecewise import Piecewise
from sympy.functions.special.gamma_functions import gamma
if not piecewise:
if (x < 0) == True:
return S.NegativeOne**k*gamma(k - x) / gamma(-x)
return gamma(x + 1) / gamma(x - k + 1)
return Piecewise(
(gamma(x + 1) / gamma(x - k + 1), x >= 0),
(S.NegativeOne**k*gamma(k - x) / gamma(-x), True))
def _eval_rewrite_as_RisingFactorial(self, x, k, **kwargs):
return rf(x - k + 1, k)
def _eval_rewrite_as_binomial(self, x, k, **kwargs):
if k.is_integer:
return factorial(k) * binomial(x, k)
def _eval_rewrite_as_factorial(self, x, k, **kwargs):
from sympy.functions.elementary.piecewise import Piecewise
if x.is_integer and k.is_integer:
return Piecewise(
(factorial(x)/factorial(-k + x), x >= 0),
(S.NegativeOne**k*factorial(k - x - 1)/factorial(-x - 1), True))
def _eval_rewrite_as_tractable(self, x, k, limitvar=None, **kwargs):
from sympy.functions.special.gamma_functions import gamma
if limitvar:
k_lim = k.subs(limitvar, S.Infinity)
if k_lim is S.Infinity:
return (S.NegativeOne**k*gamma(k - x).rewrite('tractable', deep=True) / gamma(-x))
elif k_lim is S.NegativeInfinity:
return (gamma(x + 1) / gamma(x - k + 1).rewrite('tractable', deep=True))
return self.rewrite(gamma).rewrite('tractable', deep=True)
def _eval_is_integer(self):
return fuzzy_and((self.args[0].is_integer, self.args[1].is_integer,
self.args[1].is_nonnegative))
rf = RisingFactorial
ff = FallingFactorial
###############################################################################
########################### BINOMIAL COEFFICIENTS #############################
###############################################################################
class binomial(CombinatorialFunction):
r"""Implementation of the binomial coefficient. It can be defined
in two ways depending on its desired interpretation:
.. math:: \binom{n}{k} = \frac{n!}{k!(n-k)!}\ \text{or}\
\binom{n}{k} = \frac{(n)_k}{k!}
First, in a strict combinatorial sense it defines the
number of ways we can choose `k` elements from a set of
`n` elements. In this case both arguments are nonnegative
integers and binomial is computed using an efficient
algorithm based on prime factorization.
The other definition is generalization for arbitrary `n`,
however `k` must also be nonnegative. This case is very
useful when evaluating summations.
For the sake of convenience, for negative integer `k` this function
will return zero no matter the other argument.
To expand the binomial when `n` is a symbol, use either
``expand_func()`` or ``expand(func=True)``. The former will keep
the polynomial in factored form while the latter will expand the
polynomial itself. See examples for details.
Examples
========
>>> from sympy import Symbol, Rational, binomial, expand_func
>>> n = Symbol('n', integer=True, positive=True)
>>> binomial(15, 8)
6435
>>> binomial(n, -1)
0
Rows of Pascal's triangle can be generated with the binomial function:
>>> for N in range(8):
... print([binomial(N, i) for i in range(N + 1)])
...
[1]
[1, 1]
[1, 2, 1]
[1, 3, 3, 1]
[1, 4, 6, 4, 1]
[1, 5, 10, 10, 5, 1]
[1, 6, 15, 20, 15, 6, 1]
[1, 7, 21, 35, 35, 21, 7, 1]
As can a given diagonal, e.g. the 4th diagonal:
>>> N = -4
>>> [binomial(N, i) for i in range(1 - N)]
[1, -4, 10, -20, 35]
>>> binomial(Rational(5, 4), 3)
-5/128
>>> binomial(Rational(-5, 4), 3)
-195/128
>>> binomial(n, 3)
binomial(n, 3)
>>> binomial(n, 3).expand(func=True)
n**3/6 - n**2/2 + n/3
>>> expand_func(binomial(n, 3))
n*(n - 2)*(n - 1)/6
In many cases, we can also compute binomial coefficients modulo a
prime p quickly using Lucas' Theorem [2]_, though we need to include
`evaluate=False` to postpone evaluation:
>>> from sympy import Mod
>>> Mod(binomial(156675, 4433, evaluate=False), 10**5 + 3)
28625
Using a generalisation of Lucas's Theorem given by Granville [3]_,
we can extend this to arbitrary n:
>>> Mod(binomial(10**18, 10**12, evaluate=False), (10**5 + 3)**2)
3744312326
References
==========
.. [1] https://www.johndcook.com/blog/binomial_coefficients/
.. [2] https://en.wikipedia.org/wiki/Lucas%27s_theorem
.. [3] Binomial coefficients modulo prime powers, Andrew Granville,
Available: https://web.archive.org/web/20170202003812/http://www.dms.umontreal.ca/~andrew/PDF/BinCoeff.pdf
"""
def fdiff(self, argindex=1):
from sympy.functions.special.gamma_functions import polygamma
if argindex == 1:
# https://functions.wolfram.com/GammaBetaErf/Binomial/20/01/01/
n, k = self.args
return binomial(n, k)*(polygamma(0, n + 1) - \
polygamma(0, n - k + 1))
elif argindex == 2:
# https://functions.wolfram.com/GammaBetaErf/Binomial/20/01/02/
n, k = self.args
return binomial(n, k)*(polygamma(0, n - k + 1) - \
polygamma(0, k + 1))
else:
raise ArgumentIndexError(self, argindex)
@classmethod
def _eval(self, n, k):
# n.is_Number and k.is_Integer and k != 1 and n != k
if k.is_Integer:
if n.is_Integer and n >= 0:
n, k = int(n), int(k)
if k > n:
return S.Zero
elif k > n // 2:
k = n - k
# XXX: This conditional logic should be moved to
# sympy.external.gmpy and the pure Python version of bincoef
# should be moved to sympy.external.ntheory.
if _gmpy is not None:
return Integer(_gmpy.bincoef(n, k))
d, result = n - k, 1
for i in range(1, k + 1):
d += 1
result = result * d // i
return Integer(result)
else:
d, result = n - k, 1
for i in range(1, k + 1):
d += 1
result *= d
return result / _factorial(k)
@classmethod
def eval(cls, n, k):
n, k = map(sympify, (n, k))
d = n - k
n_nonneg, n_isint = n.is_nonnegative, n.is_integer
if k.is_zero or ((n_nonneg or n_isint is False)
and d.is_zero):
return S.One
if (k - 1).is_zero or ((n_nonneg or n_isint is False)
and (d - 1).is_zero):
return n
if k.is_integer:
if k.is_negative or (n_nonneg and n_isint and d.is_negative):
return S.Zero
elif n.is_number:
res = cls._eval(n, k)
return res.expand(basic=True) if res else res
elif n_nonneg is False and n_isint:
# a special case when binomial evaluates to complex infinity
return S.ComplexInfinity
elif k.is_number:
from sympy.functions.special.gamma_functions import gamma
return gamma(n + 1)/(gamma(k + 1)*gamma(n - k + 1))
def _eval_Mod(self, q):
n, k = self.args
if any(x.is_integer is False for x in (n, k, q)):
raise ValueError("Integers expected for binomial Mod")
if all(x.is_Integer for x in (n, k, q)):
n, k = map(int, (n, k))
aq, res = abs(q), 1
# handle negative integers k or n
if k < 0:
return S.Zero
if n < 0:
n = -n + k - 1
res = -1 if k%2 else 1
# non negative integers k and n
if k > n:
return S.Zero
isprime = aq.is_prime
aq = int(aq)
if isprime:
if aq < n:
# use Lucas Theorem
N, K = n, k
while N or K:
res = res*binomial(N % aq, K % aq) % aq
N, K = N // aq, K // aq
else:
# use Factorial Modulo
d = n - k
if k > d:
k, d = d, k
kf = 1
for i in range(2, k + 1):
kf = kf*i % aq
df = kf
for i in range(k + 1, d + 1):
df = df*i % aq
res *= df
for i in range(d + 1, n + 1):
res = res*i % aq
res *= pow(kf*df % aq, aq - 2, aq)
res %= aq
elif _sqrt(q) < k and q != 1:
res = binomial_mod(n, k, q)
else:
# Binomial Factorization is performed by calculating the
# exponents of primes <= n in `n! /(k! (n - k)!)`,
# for non-negative integers n and k. As the exponent of
# prime in n! is e_p(n) = [n/p] + [n/p**2] + ...
# the exponent of prime in binomial(n, k) would be
# e_p(n) - e_p(k) - e_p(n - k)
M = int(_sqrt(n))
for prime in sieve.primerange(2, n + 1):
if prime > n - k:
res = res*prime % aq
elif prime > n // 2:
continue
elif prime > M:
if n % prime < k % prime:
res = res*prime % aq
else:
N, K = n, k
exp = a = 0
while N > 0:
a = int((N % prime) < (K % prime + a))
N, K = N // prime, K // prime
exp += a
if exp > 0:
res *= pow(prime, exp, aq)
res %= aq
return S(res % q)
def _eval_expand_func(self, **hints):
"""
Function to expand binomial(n, k) when m is positive integer
Also,
n is self.args[0] and k is self.args[1] while using binomial(n, k)
"""
n = self.args[0]
if n.is_Number:
return binomial(*self.args)
k = self.args[1]
if (n-k).is_Integer:
k = n - k
if k.is_Integer:
if k.is_zero:
return S.One
elif k.is_negative:
return S.Zero
else:
n, result = self.args[0], 1
for i in range(1, k + 1):
result *= n - k + i
return result / _factorial(k)
else:
return binomial(*self.args)
def _eval_rewrite_as_factorial(self, n, k, **kwargs):
return factorial(n)/(factorial(k)*factorial(n - k))
def _eval_rewrite_as_gamma(self, n, k, piecewise=True, **kwargs):
from sympy.functions.special.gamma_functions import gamma
return gamma(n + 1)/(gamma(k + 1)*gamma(n - k + 1))
def _eval_rewrite_as_tractable(self, n, k, limitvar=None, **kwargs):
return self._eval_rewrite_as_gamma(n, k).rewrite('tractable')
def _eval_rewrite_as_FallingFactorial(self, n, k, **kwargs):
if k.is_integer:
return ff(n, k) / factorial(k)
def _eval_is_integer(self):
n, k = self.args
if n.is_integer and k.is_integer:
return True
elif k.is_integer is False:
return False
def _eval_is_nonnegative(self):
n, k = self.args
if n.is_integer and k.is_integer:
if n.is_nonnegative or k.is_negative or k.is_even:
return True
elif k.is_even is False:
return False
def _eval_as_leading_term(self, x, logx=None, cdir=0):
from sympy.functions.special.gamma_functions import gamma
return self.rewrite(gamma)._eval_as_leading_term(x, logx=logx, cdir=cdir)
PK ]ZZZ Z6�o� o� ( sympy/functions/combinatorial/numbers.py"""
This module implements some special functions that commonly appear in
combinatorial contexts (e.g. in power series); in particular,
sequences of rational numbers such as Bernoulli and Fibonacci numbers.
Factorials, binomial coefficients and related functions are located in
the separate 'factorials' module.
"""
from math import prod
from collections import defaultdict
from typing import Tuple as tTuple
from sympy.core import S, Symbol, Add, Dummy
from sympy.core.cache import cacheit
from sympy.core.containers import Dict
from sympy.core.expr import Expr
from sympy.core.function import ArgumentIndexError, Function, expand_mul
from sympy.core.logic import fuzzy_not
from sympy.core.mul import Mul
from sympy.core.numbers import E, I, pi, oo, Rational, Integer
from sympy.core.relational import Eq, is_le, is_gt, is_lt
from sympy.external.gmpy import SYMPY_INTS, remove, lcm, legendre, jacobi, kronecker
from sympy.functions.combinatorial.factorials import (binomial,
factorial, subfactorial)
from sympy.functions.elementary.exponential import log
from sympy.functions.elementary.piecewise import Piecewise
from sympy.ntheory.factor_ import (factorint, _divisor_sigma, is_carmichael,
find_carmichael_numbers_in_range, find_first_n_carmichaels)
from sympy.ntheory.generate import _primepi
from sympy.ntheory.partitions_ import _partition, _partition_rec
from sympy.ntheory.primetest import isprime, is_square
from sympy.polys.appellseqs import bernoulli_poly, euler_poly, genocchi_poly
from sympy.polys.polytools import cancel
from sympy.utilities.enumerative import MultisetPartitionTraverser
from sympy.utilities.exceptions import sympy_deprecation_warning
from sympy.utilities.iterables import multiset, multiset_derangements, iterable
from sympy.utilities.memoization import recurrence_memo
from sympy.utilities.misc import as_int
from mpmath import mp, workprec
from mpmath.libmp import ifib as _ifib
def _product(a, b):
return prod(range(a, b + 1))
# Dummy symbol used for computing polynomial sequences
_sym = Symbol('x')
#----------------------------------------------------------------------------#
# #
# Carmichael numbers #
# #
#----------------------------------------------------------------------------#
class carmichael(Function):
r"""
Carmichael Numbers:
Certain cryptographic algorithms make use of big prime numbers.
However, checking whether a big number is prime is not so easy.
Randomized prime number checking tests exist that offer a high degree of
confidence of accurate determination at low cost, such as the Fermat test.
Let 'a' be a random number between $2$ and $n - 1$, where $n$ is the
number whose primality we are testing. Then, $n$ is probably prime if it
satisfies the modular arithmetic congruence relation:
.. math :: a^{n-1} = 1 \pmod{n}
(where mod refers to the modulo operation)
If a number passes the Fermat test several times, then it is prime with a
high probability.
Unfortunately, certain composite numbers (non-primes) still pass the Fermat
test with every number smaller than themselves.
These numbers are called Carmichael numbers.
A Carmichael number will pass a Fermat primality test to every base $b$
relatively prime to the number, even though it is not actually prime.
This makes tests based on Fermat's Little Theorem less effective than
strong probable prime tests such as the Baillie-PSW primality test and
the Miller-Rabin primality test.
Examples
========
>>> from sympy.ntheory.factor_ import find_first_n_carmichaels, find_carmichael_numbers_in_range
>>> find_first_n_carmichaels(5)
[561, 1105, 1729, 2465, 2821]
>>> find_carmichael_numbers_in_range(0, 562)
[561]
>>> find_carmichael_numbers_in_range(0,1000)
[561]
>>> find_carmichael_numbers_in_range(0,2000)
[561, 1105, 1729]
References
==========
.. [1] https://en.wikipedia.org/wiki/Carmichael_number
.. [2] https://en.wikipedia.org/wiki/Fermat_primality_test
.. [3] https://www.jstor.org/stable/23248683?seq=1#metadata_info_tab_contents
"""
@staticmethod
def is_perfect_square(n):
sympy_deprecation_warning(
"""
is_perfect_square is just a wrapper around sympy.ntheory.primetest.is_square
so use that directly instead.
""",
deprecated_since_version="1.11",
active_deprecations_target='deprecated-carmichael-static-methods',
)
return is_square(n)
@staticmethod
def divides(p, n):
sympy_deprecation_warning(
"""
divides can be replaced by directly testing n % p == 0.
""",
deprecated_since_version="1.11",
active_deprecations_target='deprecated-carmichael-static-methods',
)
return n % p == 0
@staticmethod
def is_prime(n):
sympy_deprecation_warning(
"""
is_prime is just a wrapper around sympy.ntheory.primetest.isprime so use that
directly instead.
""",
deprecated_since_version="1.11",
active_deprecations_target='deprecated-carmichael-static-methods',
)
return isprime(n)
@staticmethod
def is_carmichael(n):
sympy_deprecation_warning(
"""
is_carmichael is just a wrapper around sympy.ntheory.factor_.is_carmichael so use that
directly instead.
""",
deprecated_since_version="1.13",
active_deprecations_target='deprecated-ntheory-symbolic-functions',
)
return is_carmichael(n)
@staticmethod
def find_carmichael_numbers_in_range(x, y):
sympy_deprecation_warning(
"""
find_carmichael_numbers_in_range is just a wrapper around sympy.ntheory.factor_.find_carmichael_numbers_in_range so use that
directly instead.
""",
deprecated_since_version="1.13",
active_deprecations_target='deprecated-ntheory-symbolic-functions',
)
return find_carmichael_numbers_in_range(x, y)
@staticmethod
def find_first_n_carmichaels(n):
sympy_deprecation_warning(
"""
find_first_n_carmichaels is just a wrapper around sympy.ntheory.factor_.find_first_n_carmichaels so use that
directly instead.
""",
deprecated_since_version="1.13",
active_deprecations_target='deprecated-ntheory-symbolic-functions',
)
return find_first_n_carmichaels(n)
#----------------------------------------------------------------------------#
# #
# Fibonacci numbers #
# #
#----------------------------------------------------------------------------#
class fibonacci(Function):
r"""
Fibonacci numbers / Fibonacci polynomials
The Fibonacci numbers are the integer sequence defined by the
initial terms `F_0 = 0`, `F_1 = 1` and the two-term recurrence
relation `F_n = F_{n-1} + F_{n-2}`. This definition
extended to arbitrary real and complex arguments using
the formula
.. math :: F_z = \frac{\phi^z - \cos(\pi z) \phi^{-z}}{\sqrt 5}
The Fibonacci polynomials are defined by `F_1(x) = 1`,
`F_2(x) = x`, and `F_n(x) = x*F_{n-1}(x) + F_{n-2}(x)` for `n > 2`.
For all positive integers `n`, `F_n(1) = F_n`.
* ``fibonacci(n)`` gives the `n^{th}` Fibonacci number, `F_n`
* ``fibonacci(n, x)`` gives the `n^{th}` Fibonacci polynomial in `x`, `F_n(x)`
Examples
========
>>> from sympy import fibonacci, Symbol
>>> [fibonacci(x) for x in range(11)]
[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55]
>>> fibonacci(5, Symbol('t'))
t**4 + 3*t**2 + 1
See Also
========
bell, bernoulli, catalan, euler, harmonic, lucas, genocchi, partition, tribonacci
References
==========
.. [1] https://en.wikipedia.org/wiki/Fibonacci_number
.. [2] https://mathworld.wolfram.com/FibonacciNumber.html
"""
@staticmethod
def _fib(n):
return _ifib(n)
@staticmethod
@recurrence_memo([None, S.One, _sym])
def _fibpoly(n, prev):
return (prev[-2] + _sym*prev[-1]).expand()
@classmethod
def eval(cls, n, sym=None):
if n is S.Infinity:
return S.Infinity
if n.is_Integer:
if sym is None:
n = int(n)
if n < 0:
return S.NegativeOne**(n + 1) * fibonacci(-n)
else:
return Integer(cls._fib(n))
else:
if n < 1:
raise ValueError("Fibonacci polynomials are defined "
"only for positive integer indices.")
return cls._fibpoly(n).subs(_sym, sym)
def _eval_rewrite_as_tractable(self, n, **kwargs):
from sympy.functions import sqrt, cos
return (S.GoldenRatio**n - cos(S.Pi*n)/S.GoldenRatio**n)/sqrt(5)
def _eval_rewrite_as_sqrt(self, n, **kwargs):
from sympy.functions.elementary.miscellaneous import sqrt
return 2**(-n)*sqrt(5)*((1 + sqrt(5))**n - (-sqrt(5) + 1)**n) / 5
def _eval_rewrite_as_GoldenRatio(self,n, **kwargs):
return (S.GoldenRatio**n - 1/(-S.GoldenRatio)**n)/(2*S.GoldenRatio-1)
#----------------------------------------------------------------------------#
# #
# Lucas numbers #
# #
#----------------------------------------------------------------------------#
class lucas(Function):
"""
Lucas numbers
Lucas numbers satisfy a recurrence relation similar to that of
the Fibonacci sequence, in which each term is the sum of the
preceding two. They are generated by choosing the initial
values `L_0 = 2` and `L_1 = 1`.
* ``lucas(n)`` gives the `n^{th}` Lucas number
Examples
========
>>> from sympy import lucas
>>> [lucas(x) for x in range(11)]
[2, 1, 3, 4, 7, 11, 18, 29, 47, 76, 123]
See Also
========
bell, bernoulli, catalan, euler, fibonacci, harmonic, genocchi, partition, tribonacci
References
==========
.. [1] https://en.wikipedia.org/wiki/Lucas_number
.. [2] https://mathworld.wolfram.com/LucasNumber.html
"""
@classmethod
def eval(cls, n):
if n is S.Infinity:
return S.Infinity
if n.is_Integer:
return fibonacci(n + 1) + fibonacci(n - 1)
def _eval_rewrite_as_sqrt(self, n, **kwargs):
from sympy.functions.elementary.miscellaneous import sqrt
return 2**(-n)*((1 + sqrt(5))**n + (-sqrt(5) + 1)**n)
#----------------------------------------------------------------------------#
# #
# Tribonacci numbers #
# #
#----------------------------------------------------------------------------#
class tribonacci(Function):
r"""
Tribonacci numbers / Tribonacci polynomials
The Tribonacci numbers are the integer sequence defined by the
initial terms `T_0 = 0`, `T_1 = 1`, `T_2 = 1` and the three-term
recurrence relation `T_n = T_{n-1} + T_{n-2} + T_{n-3}`.
The Tribonacci polynomials are defined by `T_0(x) = 0`, `T_1(x) = 1`,
`T_2(x) = x^2`, and `T_n(x) = x^2 T_{n-1}(x) + x T_{n-2}(x) + T_{n-3}(x)`
for `n > 2`. For all positive integers `n`, `T_n(1) = T_n`.
* ``tribonacci(n)`` gives the `n^{th}` Tribonacci number, `T_n`
* ``tribonacci(n, x)`` gives the `n^{th}` Tribonacci polynomial in `x`, `T_n(x)`
Examples
========
>>> from sympy import tribonacci, Symbol
>>> [tribonacci(x) for x in range(11)]
[0, 1, 1, 2, 4, 7, 13, 24, 44, 81, 149]
>>> tribonacci(5, Symbol('t'))
t**8 + 3*t**5 + 3*t**2
See Also
========
bell, bernoulli, catalan, euler, fibonacci, harmonic, lucas, genocchi, partition
References
==========
.. [1] https://en.wikipedia.org/wiki/Generalizations_of_Fibonacci_numbers#Tribonacci_numbers
.. [2] https://mathworld.wolfram.com/TribonacciNumber.html
.. [3] https://oeis.org/A000073
"""
@staticmethod
@recurrence_memo([S.Zero, S.One, S.One])
def _trib(n, prev):
return (prev[-3] + prev[-2] + prev[-1])
@staticmethod
@recurrence_memo([S.Zero, S.One, _sym**2])
def _tribpoly(n, prev):
return (prev[-3] + _sym*prev[-2] + _sym**2*prev[-1]).expand()
@classmethod
def eval(cls, n, sym=None):
if n is S.Infinity:
return S.Infinity
if n.is_Integer:
n = int(n)
if n < 0:
raise ValueError("Tribonacci polynomials are defined "
"only for non-negative integer indices.")
if sym is None:
return Integer(cls._trib(n))
else:
return cls._tribpoly(n).subs(_sym, sym)
def _eval_rewrite_as_sqrt(self, n, **kwargs):
from sympy.functions.elementary.miscellaneous import cbrt, sqrt
w = (-1 + S.ImaginaryUnit * sqrt(3)) / 2
a = (1 + cbrt(19 + 3*sqrt(33)) + cbrt(19 - 3*sqrt(33))) / 3
b = (1 + w*cbrt(19 + 3*sqrt(33)) + w**2*cbrt(19 - 3*sqrt(33))) / 3
c = (1 + w**2*cbrt(19 + 3*sqrt(33)) + w*cbrt(19 - 3*sqrt(33))) / 3
Tn = (a**(n + 1)/((a - b)*(a - c))
+ b**(n + 1)/((b - a)*(b - c))
+ c**(n + 1)/((c - a)*(c - b)))
return Tn
def _eval_rewrite_as_TribonacciConstant(self, n, **kwargs):
from sympy.functions.elementary.integers import floor
from sympy.functions.elementary.miscellaneous import cbrt, sqrt
b = cbrt(586 + 102*sqrt(33))
Tn = 3 * b * S.TribonacciConstant**n / (b**2 - 2*b + 4)
return floor(Tn + S.Half)
#----------------------------------------------------------------------------#
# #
# Bernoulli numbers #
# #
#----------------------------------------------------------------------------#
class bernoulli(Function):
r"""
Bernoulli numbers / Bernoulli polynomials / Bernoulli function
The Bernoulli numbers are a sequence of rational numbers
defined by `B_0 = 1` and the recursive relation (`n > 0`):
.. math :: n+1 = \sum_{k=0}^n \binom{n+1}{k} B_k
They are also commonly defined by their exponential generating
function, which is `\frac{x}{1 - e^{-x}}`. For odd indices > 1,
the Bernoulli numbers are zero.
The Bernoulli polynomials satisfy the analogous formula:
.. math :: B_n(x) = \sum_{k=0}^n (-1)^k \binom{n}{k} B_k x^{n-k}
Bernoulli numbers and Bernoulli polynomials are related as
`B_n(1) = B_n`.
The generalized Bernoulli function `\operatorname{B}(s, a)`
is defined for any complex `s` and `a`, except where `a` is a
nonpositive integer and `s` is not a nonnegative integer. It is
an entire function of `s` for fixed `a`, related to the Hurwitz
zeta function by
.. math:: \operatorname{B}(s, a) = \begin{cases}
-s \zeta(1-s, a) & s \ne 0 \\ 1 & s = 0 \end{cases}
When `s` is a nonnegative integer this function reduces to the
Bernoulli polynomials: `\operatorname{B}(n, x) = B_n(x)`. When
`a` is omitted it is assumed to be 1, yielding the (ordinary)
Bernoulli function which interpolates the Bernoulli numbers and is
related to the Riemann zeta function.
We compute Bernoulli numbers using Ramanujan's formula:
.. math :: B_n = \frac{A(n) - S(n)}{\binom{n+3}{n}}
where:
.. math :: A(n) = \begin{cases} \frac{n+3}{3} &
n \equiv 0\ \text{or}\ 2 \pmod{6} \\
-\frac{n+3}{6} & n \equiv 4 \pmod{6} \end{cases}
and:
.. math :: S(n) = \sum_{k=1}^{[n/6]} \binom{n+3}{n-6k} B_{n-6k}
This formula is similar to the sum given in the definition, but
cuts `\frac{2}{3}` of the terms. For Bernoulli polynomials, we use
Appell sequences.
For `n` a nonnegative integer and `s`, `a`, `x` arbitrary complex numbers,
* ``bernoulli(n)`` gives the nth Bernoulli number, `B_n`
* ``bernoulli(s)`` gives the Bernoulli function `\operatorname{B}(s)`
* ``bernoulli(n, x)`` gives the nth Bernoulli polynomial in `x`, `B_n(x)`
* ``bernoulli(s, a)`` gives the generalized Bernoulli function
`\operatorname{B}(s, a)`
.. versionchanged:: 1.12
``bernoulli(1)`` gives `+\frac{1}{2}` instead of `-\frac{1}{2}`.
This choice of value confers several theoretical advantages [5]_,
including the extension to complex parameters described above
which this function now implements. The previous behavior, defined
only for nonnegative integers `n`, can be obtained with
``(-1)**n*bernoulli(n)``.
Examples
========
>>> from sympy import bernoulli
>>> from sympy.abc import x
>>> [bernoulli(n) for n in range(11)]
[1, 1/2, 1/6, 0, -1/30, 0, 1/42, 0, -1/30, 0, 5/66]
>>> bernoulli(1000001)
0
>>> bernoulli(3, x)
x**3 - 3*x**2/2 + x/2
See Also
========
andre, bell, catalan, euler, fibonacci, harmonic, lucas, genocchi,
partition, tribonacci, sympy.polys.appellseqs.bernoulli_poly
References
==========
.. [1] https://en.wikipedia.org/wiki/Bernoulli_number
.. [2] https://en.wikipedia.org/wiki/Bernoulli_polynomial
.. [3] https://mathworld.wolfram.com/BernoulliNumber.html
.. [4] https://mathworld.wolfram.com/BernoulliPolynomial.html
.. [5] Peter Luschny, "The Bernoulli Manifesto",
https://luschny.de/math/zeta/The-Bernoulli-Manifesto.html
.. [6] Peter Luschny, "An introduction to the Bernoulli function",
https://arxiv.org/abs/2009.06743
"""
args: tTuple[Integer]
# Calculates B_n for positive even n
@staticmethod
def _calc_bernoulli(n):
s = 0
a = int(binomial(n + 3, n - 6))
for j in range(1, n//6 + 1):
s += a * bernoulli(n - 6*j)
# Avoid computing each binomial coefficient from scratch
a *= _product(n - 6 - 6*j + 1, n - 6*j)
a //= _product(6*j + 4, 6*j + 9)
if n % 6 == 4:
s = -Rational(n + 3, 6) - s
else:
s = Rational(n + 3, 3) - s
return s / binomial(n + 3, n)
# We implement a specialized memoization scheme to handle each
# case modulo 6 separately
_cache = {0: S.One, 1: Rational(1, 2), 2: Rational(1, 6), 4: Rational(-1, 30)}
_highest = {0: 0, 1: 1, 2: 2, 4: 4}
@classmethod
def eval(cls, n, x=None):
if x is S.One:
return cls(n)
elif n.is_zero:
return S.One
elif n.is_integer is False or n.is_nonnegative is False:
if x is not None and x.is_Integer and x.is_nonpositive:
return S.NaN
return
# Bernoulli numbers
elif x is None:
if n is S.One:
return S.Half
elif n.is_odd and (n-1).is_positive:
return S.Zero
elif n.is_Number:
n = int(n)
# Use mpmath for enormous Bernoulli numbers
if n > 500:
p, q = mp.bernfrac(n)
return Rational(int(p), int(q))
case = n % 6
highest_cached = cls._highest[case]
if n <= highest_cached:
return cls._cache[n]
# To avoid excessive recursion when, say, bernoulli(1000) is
# requested, calculate and cache the entire sequence ... B_988,
# B_994, B_1000 in increasing order
for i in range(highest_cached + 6, n + 6, 6):
b = cls._calc_bernoulli(i)
cls._cache[i] = b
cls._highest[case] = i
return b
# Bernoulli polynomials
elif n.is_Number:
return bernoulli_poly(n, x)
def _eval_rewrite_as_zeta(self, n, x=1, **kwargs):
from sympy.functions.special.zeta_functions import zeta
return Piecewise((1, Eq(n, 0)), (-n * zeta(1-n, x), True))
def _eval_evalf(self, prec):
if not all(x.is_number for x in self.args):
return
n = self.args[0]._to_mpmath(prec)
x = (self.args[1] if len(self.args) > 1 else S.One)._to_mpmath(prec)
with workprec(prec):
if n == 0:
res = mp.mpf(1)
elif n == 1:
res = x - mp.mpf(0.5)
elif mp.isint(n) and n >= 0:
res = mp.bernoulli(n) if x == 1 else mp.bernpoly(n, x)
else:
res = -n * mp.zeta(1-n, x)
return Expr._from_mpmath(res, prec)
#----------------------------------------------------------------------------#
# #
# Bell numbers #
# #
#----------------------------------------------------------------------------#
class bell(Function):
r"""
Bell numbers / Bell polynomials
The Bell numbers satisfy `B_0 = 1` and
.. math:: B_n = \sum_{k=0}^{n-1} \binom{n-1}{k} B_k.
They are also given by:
.. math:: B_n = \frac{1}{e} \sum_{k=0}^{\infty} \frac{k^n}{k!}.
The Bell polynomials are given by `B_0(x) = 1` and
.. math:: B_n(x) = x \sum_{k=1}^{n-1} \binom{n-1}{k-1} B_{k-1}(x).
The second kind of Bell polynomials (are sometimes called "partial" Bell
polynomials or incomplete Bell polynomials) are defined as
.. math:: B_{n,k}(x_1, x_2,\dotsc x_{n-k+1}) =
\sum_{j_1+j_2+j_2+\dotsb=k \atop j_1+2j_2+3j_2+\dotsb=n}
\frac{n!}{j_1!j_2!\dotsb j_{n-k+1}!}
\left(\frac{x_1}{1!} \right)^{j_1}
\left(\frac{x_2}{2!} \right)^{j_2} \dotsb
\left(\frac{x_{n-k+1}}{(n-k+1)!} \right) ^{j_{n-k+1}}.
* ``bell(n)`` gives the `n^{th}` Bell number, `B_n`.
* ``bell(n, x)`` gives the `n^{th}` Bell polynomial, `B_n(x)`.
* ``bell(n, k, (x1, x2, ...))`` gives Bell polynomials of the second kind,
`B_{n,k}(x_1, x_2, \dotsc, x_{n-k+1})`.
Notes
=====
Not to be confused with Bernoulli numbers and Bernoulli polynomials,
which use the same notation.
Examples
========
>>> from sympy import bell, Symbol, symbols
>>> [bell(n) for n in range(11)]
[1, 1, 2, 5, 15, 52, 203, 877, 4140, 21147, 115975]
>>> bell(30)
846749014511809332450147
>>> bell(4, Symbol('t'))
t**4 + 6*t**3 + 7*t**2 + t
>>> bell(6, 2, symbols('x:6')[1:])
6*x1*x5 + 15*x2*x4 + 10*x3**2
See Also
========
bernoulli, catalan, euler, fibonacci, harmonic, lucas, genocchi, partition, tribonacci
References
==========
.. [1] https://en.wikipedia.org/wiki/Bell_number
.. [2] https://mathworld.wolfram.com/BellNumber.html
.. [3] https://mathworld.wolfram.com/BellPolynomial.html
"""
@staticmethod
@recurrence_memo([1, 1])
def _bell(n, prev):
s = 1
a = 1
for k in range(1, n):
a = a * (n - k) // k
s += a * prev[k]
return s
@staticmethod
@recurrence_memo([S.One, _sym])
def _bell_poly(n, prev):
s = 1
a = 1
for k in range(2, n + 1):
a = a * (n - k + 1) // (k - 1)
s += a * prev[k - 1]
return expand_mul(_sym * s)
@staticmethod
def _bell_incomplete_poly(n, k, symbols):
r"""
The second kind of Bell polynomials (incomplete Bell polynomials).
Calculated by recurrence formula:
.. math:: B_{n,k}(x_1, x_2, \dotsc, x_{n-k+1}) =
\sum_{m=1}^{n-k+1}
\x_m \binom{n-1}{m-1} B_{n-m,k-1}(x_1, x_2, \dotsc, x_{n-m-k})
where
`B_{0,0} = 1;`
`B_{n,0} = 0; for n \ge 1`
`B_{0,k} = 0; for k \ge 1`
"""
if (n == 0) and (k == 0):
return S.One
elif (n == 0) or (k == 0):
return S.Zero
s = S.Zero
a = S.One
for m in range(1, n - k + 2):
s += a * bell._bell_incomplete_poly(
n - m, k - 1, symbols) * symbols[m - 1]
a = a * (n - m) / m
return expand_mul(s)
@classmethod
def eval(cls, n, k_sym=None, symbols=None):
if n is S.Infinity:
if k_sym is None:
return S.Infinity
else:
raise ValueError("Bell polynomial is not defined")
if n.is_negative or n.is_integer is False:
raise ValueError("a non-negative integer expected")
if n.is_Integer and n.is_nonnegative:
if k_sym is None:
return Integer(cls._bell(int(n)))
elif symbols is None:
return cls._bell_poly(int(n)).subs(_sym, k_sym)
else:
r = cls._bell_incomplete_poly(int(n), int(k_sym), symbols)
return r
def _eval_rewrite_as_Sum(self, n, k_sym=None, symbols=None, **kwargs):
from sympy.concrete.summations import Sum
if (k_sym is not None) or (symbols is not None):
return self
# Dobinski's formula
if not n.is_nonnegative:
return self
k = Dummy('k', integer=True, nonnegative=True)
return 1 / E * Sum(k**n / factorial(k), (k, 0, S.Infinity))
#----------------------------------------------------------------------------#
# #
# Harmonic numbers #
# #
#----------------------------------------------------------------------------#
class harmonic(Function):
r"""
Harmonic numbers
The nth harmonic number is given by `\operatorname{H}_{n} =
1 + \frac{1}{2} + \frac{1}{3} + \ldots + \frac{1}{n}`.
More generally:
.. math:: \operatorname{H}_{n,m} = \sum_{k=1}^{n} \frac{1}{k^m}
As `n \rightarrow \infty`, `\operatorname{H}_{n,m} \rightarrow \zeta(m)`,
the Riemann zeta function.
* ``harmonic(n)`` gives the nth harmonic number, `\operatorname{H}_n`
* ``harmonic(n, m)`` gives the nth generalized harmonic number
of order `m`, `\operatorname{H}_{n,m}`, where
``harmonic(n) == harmonic(n, 1)``
This function can be extended to complex `n` and `m` where `n` is not a
negative integer or `m` is a nonpositive integer as
.. math:: \operatorname{H}_{n,m} = \begin{cases} \zeta(m) - \zeta(m, n+1)
& m \ne 1 \\ \psi(n+1) + \gamma & m = 1 \end{cases}
Examples
========
>>> from sympy import harmonic, oo
>>> [harmonic(n) for n in range(6)]
[0, 1, 3/2, 11/6, 25/12, 137/60]
>>> [harmonic(n, 2) for n in range(6)]
[0, 1, 5/4, 49/36, 205/144, 5269/3600]
>>> harmonic(oo, 2)
pi**2/6
>>> from sympy import Symbol, Sum
>>> n = Symbol("n")
>>> harmonic(n).rewrite(Sum)
Sum(1/_k, (_k, 1, n))
We can evaluate harmonic numbers for all integral and positive
rational arguments:
>>> from sympy import S, expand_func, simplify
>>> harmonic(8)
761/280
>>> harmonic(11)
83711/27720
>>> H = harmonic(1/S(3))
>>> H
harmonic(1/3)
>>> He = expand_func(H)
>>> He
-log(6) - sqrt(3)*pi/6 + 2*Sum(log(sin(_k*pi/3))*cos(2*_k*pi/3), (_k, 1, 1))
+ 3*Sum(1/(3*_k + 1), (_k, 0, 0))
>>> He.doit()
-log(6) - sqrt(3)*pi/6 - log(sqrt(3)/2) + 3
>>> H = harmonic(25/S(7))
>>> He = simplify(expand_func(H).doit())
>>> He
log(sin(2*pi/7)**(2*cos(16*pi/7))/(14*sin(pi/7)**(2*cos(pi/7))*cos(pi/14)**(2*sin(pi/14)))) + pi*tan(pi/14)/2 + 30247/9900
>>> He.n(40)
1.983697455232980674869851942390639915940
>>> harmonic(25/S(7)).n(40)
1.983697455232980674869851942390639915940
We can rewrite harmonic numbers in terms of polygamma functions:
>>> from sympy import digamma, polygamma
>>> m = Symbol("m", integer=True, positive=True)
>>> harmonic(n).rewrite(digamma)
polygamma(0, n + 1) + EulerGamma
>>> harmonic(n).rewrite(polygamma)
polygamma(0, n + 1) + EulerGamma
>>> harmonic(n,3).rewrite(polygamma)
polygamma(2, n + 1)/2 + zeta(3)
>>> simplify(harmonic(n,m).rewrite(polygamma))
Piecewise((polygamma(0, n + 1) + EulerGamma, Eq(m, 1)),
(-(-1)**m*polygamma(m - 1, n + 1)/factorial(m - 1) + zeta(m), True))
Integer offsets in the argument can be pulled out:
>>> from sympy import expand_func
>>> expand_func(harmonic(n+4))
harmonic(n) + 1/(n + 4) + 1/(n + 3) + 1/(n + 2) + 1/(n + 1)
>>> expand_func(harmonic(n-4))
harmonic(n) - 1/(n - 1) - 1/(n - 2) - 1/(n - 3) - 1/n
Some limits can be computed as well:
>>> from sympy import limit, oo
>>> limit(harmonic(n), n, oo)
oo
>>> limit(harmonic(n, 2), n, oo)
pi**2/6
>>> limit(harmonic(n, 3), n, oo)
zeta(3)
For `m > 1`, `H_{n,m}` tends to `\zeta(m)` in the limit of infinite `n`:
>>> m = Symbol("m", positive=True)
>>> limit(harmonic(n, m+1), n, oo)
zeta(m + 1)
See Also
========
bell, bernoulli, catalan, euler, fibonacci, lucas, genocchi, partition, tribonacci
References
==========
.. [1] https://en.wikipedia.org/wiki/Harmonic_number
.. [2] https://functions.wolfram.com/GammaBetaErf/HarmonicNumber/
.. [3] https://functions.wolfram.com/GammaBetaErf/HarmonicNumber2/
"""
@classmethod
def eval(cls, n, m=None):
from sympy.functions.special.zeta_functions import zeta
if m is S.One:
return cls(n)
if m is None:
m = S.One
if n.is_zero:
return S.Zero
elif m.is_zero:
return n
elif n is S.Infinity:
if m.is_negative:
return S.NaN
elif is_le(m, S.One):
return S.Infinity
elif is_gt(m, S.One):
return zeta(m)
elif m.is_Integer and m.is_nonpositive:
return (bernoulli(1-m, n+1) - bernoulli(1-m)) / (1-m)
elif n.is_Integer:
if n.is_negative and (m.is_integer is False or m.is_nonpositive is False):
return S.ComplexInfinity if m is S.One else S.NaN
if n.is_nonnegative:
return Add(*(k**(-m) for k in range(1, int(n)+1)))
def _eval_rewrite_as_polygamma(self, n, m=S.One, **kwargs):
from sympy.functions.special.gamma_functions import gamma, polygamma
if m.is_integer and m.is_positive:
return Piecewise((polygamma(0, n+1) + S.EulerGamma, Eq(m, 1)),
(S.NegativeOne**m * (polygamma(m-1, 1) - polygamma(m-1, n+1)) /
gamma(m), True))
def _eval_rewrite_as_digamma(self, n, m=1, **kwargs):
from sympy.functions.special.gamma_functions import polygamma
return self.rewrite(polygamma)
def _eval_rewrite_as_trigamma(self, n, m=1, **kwargs):
from sympy.functions.special.gamma_functions import polygamma
return self.rewrite(polygamma)
def _eval_rewrite_as_Sum(self, n, m=None, **kwargs):
from sympy.concrete.summations import Sum
k = Dummy("k", integer=True)
if m is None:
m = S.One
return Sum(k**(-m), (k, 1, n))
def _eval_rewrite_as_zeta(self, n, m=S.One, **kwargs):
from sympy.functions.special.zeta_functions import zeta
from sympy.functions.special.gamma_functions import digamma
return Piecewise((digamma(n + 1) + S.EulerGamma, Eq(m, 1)),
(zeta(m) - zeta(m, n+1), True))
def _eval_expand_func(self, **hints):
from sympy.concrete.summations import Sum
n = self.args[0]
m = self.args[1] if len(self.args) == 2 else 1
if m == S.One:
if n.is_Add:
off = n.args[0]
nnew = n - off
if off.is_Integer and off.is_positive:
result = [S.One/(nnew + i) for i in range(off, 0, -1)] + [harmonic(nnew)]
return Add(*result)
elif off.is_Integer and off.is_negative:
result = [-S.One/(nnew + i) for i in range(0, off, -1)] + [harmonic(nnew)]
return Add(*result)
if n.is_Rational:
# Expansions for harmonic numbers at general rational arguments (u + p/q)
# Split n as u + p/q with p < q
p, q = n.as_numer_denom()
u = p // q
p = p - u * q
if u.is_nonnegative and p.is_positive and q.is_positive and p < q:
from sympy.functions.elementary.exponential import log
from sympy.functions.elementary.integers import floor
from sympy.functions.elementary.trigonometric import sin, cos, cot
k = Dummy("k")
t1 = q * Sum(1 / (q * k + p), (k, 0, u))
t2 = 2 * Sum(cos((2 * pi * p * k) / S(q)) *
log(sin((pi * k) / S(q))),
(k, 1, floor((q - 1) / S(2))))
t3 = (pi / 2) * cot((pi * p) / q) + log(2 * q)
return t1 + t2 - t3
return self
def _eval_rewrite_as_tractable(self, n, m=1, limitvar=None, **kwargs):
from sympy.functions.special.zeta_functions import zeta
from sympy.functions.special.gamma_functions import polygamma
pg = self.rewrite(polygamma)
if not isinstance(pg, harmonic):
return pg.rewrite("tractable", deep=True)
arg = m - S.One
if arg.is_nonzero:
return (zeta(m) - zeta(m, n+1)).rewrite("tractable", deep=True)
def _eval_evalf(self, prec):
if not all(x.is_number for x in self.args):
return
n = self.args[0]._to_mpmath(prec)
m = (self.args[1] if len(self.args) > 1 else S.One)._to_mpmath(prec)
if mp.isint(n) and n < 0:
return S.NaN
with workprec(prec):
if m == 1:
res = mp.harmonic(n)
else:
res = mp.zeta(m) - mp.zeta(m, n+1)
return Expr._from_mpmath(res, prec)
def fdiff(self, argindex=1):
from sympy.functions.special.zeta_functions import zeta
if len(self.args) == 2:
n, m = self.args
else:
n, m = self.args + (1,)
if argindex == 1:
return m * zeta(m+1, n+1)
else:
raise ArgumentIndexError
#----------------------------------------------------------------------------#
# #
# Euler numbers #
# #
#----------------------------------------------------------------------------#
class euler(Function):
r"""
Euler numbers / Euler polynomials / Euler function
The Euler numbers are given by:
.. math:: E_{2n} = I \sum_{k=1}^{2n+1} \sum_{j=0}^k \binom{k}{j}
\frac{(-1)^j (k-2j)^{2n+1}}{2^k I^k k}
.. math:: E_{2n+1} = 0
Euler numbers and Euler polynomials are related by
.. math:: E_n = 2^n E_n\left(\frac{1}{2}\right).
We compute symbolic Euler polynomials using Appell sequences,
but numerical evaluation of the Euler polynomial is computed
more efficiently (and more accurately) using the mpmath library.
The Euler polynomials are special cases of the generalized Euler function,
related to the Genocchi function as
.. math:: \operatorname{E}(s, a) = -\frac{\operatorname{G}(s+1, a)}{s+1}
with the limit of `\psi\left(\frac{a+1}{2}\right) - \psi\left(\frac{a}{2}\right)`
being taken when `s = -1`. The (ordinary) Euler function interpolating
the Euler numbers is then obtained as
`\operatorname{E}(s) = 2^s \operatorname{E}\left(s, \frac{1}{2}\right)`.
* ``euler(n)`` gives the nth Euler number `E_n`.
* ``euler(s)`` gives the Euler function `\operatorname{E}(s)`.
* ``euler(n, x)`` gives the nth Euler polynomial `E_n(x)`.
* ``euler(s, a)`` gives the generalized Euler function `\operatorname{E}(s, a)`.
Examples
========
>>> from sympy import euler, Symbol, S
>>> [euler(n) for n in range(10)]
[1, 0, -1, 0, 5, 0, -61, 0, 1385, 0]
>>> [2**n*euler(n,1) for n in range(10)]
[1, 1, 0, -2, 0, 16, 0, -272, 0, 7936]
>>> n = Symbol("n")
>>> euler(n + 2*n)
euler(3*n)
>>> x = Symbol("x")
>>> euler(n, x)
euler(n, x)
>>> euler(0, x)
1
>>> euler(1, x)
x - 1/2
>>> euler(2, x)
x**2 - x
>>> euler(3, x)
x**3 - 3*x**2/2 + 1/4
>>> euler(4, x)
x**4 - 2*x**3 + x
>>> euler(12, S.Half)
2702765/4096
>>> euler(12)
2702765
See Also
========
andre, bell, bernoulli, catalan, fibonacci, harmonic, lucas, genocchi,
partition, tribonacci, sympy.polys.appellseqs.euler_poly
References
==========
.. [1] https://en.wikipedia.org/wiki/Euler_numbers
.. [2] https://mathworld.wolfram.com/EulerNumber.html
.. [3] https://en.wikipedia.org/wiki/Alternating_permutation
.. [4] https://mathworld.wolfram.com/AlternatingPermutation.html
"""
@classmethod
def eval(cls, n, x=None):
if n.is_zero:
return S.One
elif n is S.NegativeOne:
if x is None:
return S.Pi/2
from sympy.functions.special.gamma_functions import digamma
return digamma((x+1)/2) - digamma(x/2)
elif n.is_integer is False or n.is_nonnegative is False:
return
# Euler numbers
elif x is None:
if n.is_odd and n.is_positive:
return S.Zero
elif n.is_Number:
from mpmath import mp
n = n._to_mpmath(mp.prec)
res = mp.eulernum(n, exact=True)
return Integer(res)
# Euler polynomials
elif n.is_Number:
return euler_poly(n, x)
def _eval_rewrite_as_Sum(self, n, x=None, **kwargs):
from sympy.concrete.summations import Sum
if x is None and n.is_even:
k = Dummy("k", integer=True)
j = Dummy("j", integer=True)
n = n / 2
Em = (S.ImaginaryUnit * Sum(Sum(binomial(k, j) * (S.NegativeOne**j *
(k - 2*j)**(2*n + 1)) /
(2**k*S.ImaginaryUnit**k * k), (j, 0, k)), (k, 1, 2*n + 1)))
return Em
if x:
k = Dummy("k", integer=True)
return Sum(binomial(n, k)*euler(k)/2**k*(x - S.Half)**(n - k), (k, 0, n))
def _eval_rewrite_as_genocchi(self, n, x=None, **kwargs):
if x is None:
return Piecewise((S.Pi/2, Eq(n, -1)),
(-2**n * genocchi(n+1, S.Half) / (n+1), True))
from sympy.functions.special.gamma_functions import digamma
return Piecewise((digamma((x+1)/2) - digamma(x/2), Eq(n, -1)),
(-genocchi(n+1, x) / (n+1), True))
def _eval_evalf(self, prec):
if not all(i.is_number for i in self.args):
return
from mpmath import mp
m, x = (self.args[0], None) if len(self.args) == 1 else self.args
m = m._to_mpmath(prec)
if x is not None:
x = x._to_mpmath(prec)
with workprec(prec):
if mp.isint(m) and m >= 0:
res = mp.eulernum(m) if x is None else mp.eulerpoly(m, x)
else:
if m == -1:
res = mp.pi if x is None else mp.digamma((x+1)/2) - mp.digamma(x/2)
else:
y = 0.5 if x is None else x
res = 2 * (mp.zeta(-m, y) - 2**(m+1) * mp.zeta(-m, (y+1)/2))
if x is None:
res *= 2**m
return Expr._from_mpmath(res, prec)
#----------------------------------------------------------------------------#
# #
# Catalan numbers #
# #
#----------------------------------------------------------------------------#
class catalan(Function):
r"""
Catalan numbers
The `n^{th}` catalan number is given by:
.. math :: C_n = \frac{1}{n+1} \binom{2n}{n}
* ``catalan(n)`` gives the `n^{th}` Catalan number, `C_n`
Examples
========
>>> from sympy import (Symbol, binomial, gamma, hyper,
... catalan, diff, combsimp, Rational, I)
>>> [catalan(i) for i in range(1,10)]
[1, 2, 5, 14, 42, 132, 429, 1430, 4862]
>>> n = Symbol("n", integer=True)
>>> catalan(n)
catalan(n)
Catalan numbers can be transformed into several other, identical
expressions involving other mathematical functions
>>> catalan(n).rewrite(binomial)
binomial(2*n, n)/(n + 1)
>>> catalan(n).rewrite(gamma)
4**n*gamma(n + 1/2)/(sqrt(pi)*gamma(n + 2))
>>> catalan(n).rewrite(hyper)
hyper((-n, 1 - n), (2,), 1)
For some non-integer values of n we can get closed form
expressions by rewriting in terms of gamma functions:
>>> catalan(Rational(1, 2)).rewrite(gamma)
8/(3*pi)
We can differentiate the Catalan numbers C(n) interpreted as a
continuous real function in n:
>>> diff(catalan(n), n)
(polygamma(0, n + 1/2) - polygamma(0, n + 2) + log(4))*catalan(n)
As a more advanced example consider the following ratio
between consecutive numbers:
>>> combsimp((catalan(n + 1)/catalan(n)).rewrite(binomial))
2*(2*n + 1)/(n + 2)
The Catalan numbers can be generalized to complex numbers:
>>> catalan(I).rewrite(gamma)
4**I*gamma(1/2 + I)/(sqrt(pi)*gamma(2 + I))
and evaluated with arbitrary precision:
>>> catalan(I).evalf(20)
0.39764993382373624267 - 0.020884341620842555705*I
See Also
========
andre, bell, bernoulli, euler, fibonacci, harmonic, lucas, genocchi,
partition, tribonacci, sympy.functions.combinatorial.factorials.binomial
References
==========
.. [1] https://en.wikipedia.org/wiki/Catalan_number
.. [2] https://mathworld.wolfram.com/CatalanNumber.html
.. [3] https://functions.wolfram.com/GammaBetaErf/CatalanNumber/
.. [4] http://geometer.org/mathcircles/catalan.pdf
"""
@classmethod
def eval(cls, n):
from sympy.functions.special.gamma_functions import gamma
if (n.is_Integer and n.is_nonnegative) or \
(n.is_noninteger and n.is_negative):
return 4**n*gamma(n + S.Half)/(gamma(S.Half)*gamma(n + 2))
if (n.is_integer and n.is_negative):
if (n + 1).is_negative:
return S.Zero
if (n + 1).is_zero:
return Rational(-1, 2)
def fdiff(self, argindex=1):
from sympy.functions.elementary.exponential import log
from sympy.functions.special.gamma_functions import polygamma
n = self.args[0]
return catalan(n)*(polygamma(0, n + S.Half) - polygamma(0, n + 2) + log(4))
def _eval_rewrite_as_binomial(self, n, **kwargs):
return binomial(2*n, n)/(n + 1)
def _eval_rewrite_as_factorial(self, n, **kwargs):
return factorial(2*n) / (factorial(n+1) * factorial(n))
def _eval_rewrite_as_gamma(self, n, piecewise=True, **kwargs):
from sympy.functions.special.gamma_functions import gamma
# The gamma function allows to generalize Catalan numbers to complex n
return 4**n*gamma(n + S.Half)/(gamma(S.Half)*gamma(n + 2))
def _eval_rewrite_as_hyper(self, n, **kwargs):
from sympy.functions.special.hyper import hyper
return hyper([1 - n, -n], [2], 1)
def _eval_rewrite_as_Product(self, n, **kwargs):
from sympy.concrete.products import Product
if not (n.is_integer and n.is_nonnegative):
return self
k = Dummy('k', integer=True, positive=True)
return Product((n + k) / k, (k, 2, n))
def _eval_is_integer(self):
if self.args[0].is_integer and self.args[0].is_nonnegative:
return True
def _eval_is_positive(self):
if self.args[0].is_nonnegative:
return True
def _eval_is_composite(self):
if self.args[0].is_integer and (self.args[0] - 3).is_positive:
return True
def _eval_evalf(self, prec):
from sympy.functions.special.gamma_functions import gamma
if self.args[0].is_number:
return self.rewrite(gamma)._eval_evalf(prec)
#----------------------------------------------------------------------------#
# #
# Genocchi numbers #
# #
#----------------------------------------------------------------------------#
class genocchi(Function):
r"""
Genocchi numbers / Genocchi polynomials / Genocchi function
The Genocchi numbers are a sequence of integers `G_n` that satisfy the
relation:
.. math:: \frac{-2t}{1 + e^{-t}} = \sum_{n=0}^\infty \frac{G_n t^n}{n!}
They are related to the Bernoulli numbers by
.. math:: G_n = 2 (1 - 2^n) B_n
and generalize like the Bernoulli numbers to the Genocchi polynomials and
function as
.. math:: \operatorname{G}(s, a) = 2 \left(\operatorname{B}(s, a) -
2^s \operatorname{B}\left(s, \frac{a+1}{2}\right)\right)
.. versionchanged:: 1.12
``genocchi(1)`` gives `-1` instead of `1`.
Examples
========
>>> from sympy import genocchi, Symbol
>>> [genocchi(n) for n in range(9)]
[0, -1, -1, 0, 1, 0, -3, 0, 17]
>>> n = Symbol('n', integer=True, positive=True)
>>> genocchi(2*n + 1)
0
>>> x = Symbol('x')
>>> genocchi(4, x)
-4*x**3 + 6*x**2 - 1
See Also
========
bell, bernoulli, catalan, euler, fibonacci, harmonic, lucas, partition, tribonacci
sympy.polys.appellseqs.genocchi_poly
References
==========
.. [1] https://en.wikipedia.org/wiki/Genocchi_number
.. [2] https://mathworld.wolfram.com/GenocchiNumber.html
.. [3] Peter Luschny, "An introduction to the Bernoulli function",
https://arxiv.org/abs/2009.06743
"""
@classmethod
def eval(cls, n, x=None):
if x is S.One:
return cls(n)
elif n.is_integer is False or n.is_nonnegative is False:
return
# Genocchi numbers
elif x is None:
if n.is_odd and (n-1).is_positive:
return S.Zero
elif n.is_Number:
return 2 * (1-S(2)**n) * bernoulli(n)
# Genocchi polynomials
elif n.is_Number:
return genocchi_poly(n, x)
def _eval_rewrite_as_bernoulli(self, n, x=1, **kwargs):
if x == 1 and n.is_integer and n.is_nonnegative:
return 2 * (1-S(2)**n) * bernoulli(n)
return 2 * (bernoulli(n, x) - 2**n * bernoulli(n, (x+1) / 2))
def _eval_rewrite_as_dirichlet_eta(self, n, x=1, **kwargs):
from sympy.functions.special.zeta_functions import dirichlet_eta
return -2*n * dirichlet_eta(1-n, x)
def _eval_is_integer(self):
if len(self.args) > 1 and self.args[1] != 1:
return
n = self.args[0]
if n.is_integer and n.is_nonnegative:
return True
def _eval_is_negative(self):
if len(self.args) > 1 and self.args[1] != 1:
return
n = self.args[0]
if n.is_integer and n.is_nonnegative:
if n.is_odd:
return fuzzy_not((n-1).is_positive)
return (n/2).is_odd
def _eval_is_positive(self):
if len(self.args) > 1 and self.args[1] != 1:
return
n = self.args[0]
if n.is_integer and n.is_nonnegative:
if n.is_zero or n.is_odd:
return False
return (n/2).is_even
def _eval_is_even(self):
if len(self.args) > 1 and self.args[1] != 1:
return
n = self.args[0]
if n.is_integer and n.is_nonnegative:
if n.is_even:
return n.is_zero
return (n-1).is_positive
def _eval_is_odd(self):
if len(self.args) > 1 and self.args[1] != 1:
return
n = self.args[0]
if n.is_integer and n.is_nonnegative:
if n.is_even:
return fuzzy_not(n.is_zero)
return fuzzy_not((n-1).is_positive)
def _eval_is_prime(self):
if len(self.args) > 1 and self.args[1] != 1:
return
n = self.args[0]
# only G_6 = -3 and G_8 = 17 are prime,
# but SymPy does not consider negatives as prime
# so only n=8 is tested
return (n-8).is_zero
def _eval_evalf(self, prec):
if all(i.is_number for i in self.args):
return self.rewrite(bernoulli)._eval_evalf(prec)
#----------------------------------------------------------------------------#
# #
# Andre numbers #
# #
#----------------------------------------------------------------------------#
class andre(Function):
r"""
Andre numbers / Andre function
The Andre number `\mathcal{A}_n` is Luschny's name for half the number of
*alternating permutations* on `n` elements, where a permutation is alternating
if adjacent elements alternately compare "greater" and "smaller" going from
left to right. For example, `2 < 3 > 1 < 4` is an alternating permutation.
This sequence is A000111 in the OEIS, which assigns the names *up/down numbers*
and *Euler zigzag numbers*. It satisfies a recurrence relation similar to that
for the Catalan numbers, with `\mathcal{A}_0 = 1` and
.. math:: 2 \mathcal{A}_{n+1} = \sum_{k=0}^n \binom{n}{k} \mathcal{A}_k \mathcal{A}_{n-k}
The Bernoulli and Euler numbers are signed transformations of the odd- and
even-indexed elements of this sequence respectively:
.. math :: \operatorname{B}_{2k} = \frac{2k \mathcal{A}_{2k-1}}{(-4)^k - (-16)^k}
.. math :: \operatorname{E}_{2k} = (-1)^k \mathcal{A}_{2k}
Like the Bernoulli and Euler numbers, the Andre numbers are interpolated by the
entire Andre function:
.. math :: \mathcal{A}(s) = (-i)^{s+1} \operatorname{Li}_{-s}(i) +
i^{s+1} \operatorname{Li}_{-s}(-i) = \\ \frac{2 \Gamma(s+1)}{(2\pi)^{s+1}}
(\zeta(s+1, 1/4) - \zeta(s+1, 3/4) \cos{\pi s})
Examples
========
>>> from sympy import andre, euler, bernoulli
>>> [andre(n) for n in range(11)]
[1, 1, 1, 2, 5, 16, 61, 272, 1385, 7936, 50521]
>>> [(-1)**k * andre(2*k) for k in range(7)]
[1, -1, 5, -61, 1385, -50521, 2702765]
>>> [euler(2*k) for k in range(7)]
[1, -1, 5, -61, 1385, -50521, 2702765]
>>> [andre(2*k-1) * (2*k) / ((-4)**k - (-16)**k) for k in range(1, 8)]
[1/6, -1/30, 1/42, -1/30, 5/66, -691/2730, 7/6]
>>> [bernoulli(2*k) for k in range(1, 8)]
[1/6, -1/30, 1/42, -1/30, 5/66, -691/2730, 7/6]
See Also
========
bernoulli, catalan, euler, sympy.polys.appellseqs.andre_poly
References
==========
.. [1] https://en.wikipedia.org/wiki/Alternating_permutation
.. [2] https://mathworld.wolfram.com/EulerZigzagNumber.html
.. [3] Peter Luschny, "An introduction to the Bernoulli function",
https://arxiv.org/abs/2009.06743
"""
@classmethod
def eval(cls, n):
if n is S.NaN:
return S.NaN
elif n is S.Infinity:
return S.Infinity
if n.is_zero:
return S.One
elif n == -1:
return -log(2)
elif n == -2:
return -2*S.Catalan
elif n.is_Integer:
if n.is_nonnegative and n.is_even:
return abs(euler(n))
elif n.is_odd:
from sympy.functions.special.zeta_functions import zeta
m = -n-1
return I**m * Rational(1-2**m, 4**m) * zeta(-n)
def _eval_rewrite_as_zeta(self, s, **kwargs):
from sympy.functions.elementary.trigonometric import cos
from sympy.functions.special.gamma_functions import gamma
from sympy.functions.special.zeta_functions import zeta
return 2 * gamma(s+1) / (2*pi)**(s+1) * \
(zeta(s+1, S.One/4) - cos(pi*s) * zeta(s+1, S(3)/4))
def _eval_rewrite_as_polylog(self, s, **kwargs):
from sympy.functions.special.zeta_functions import polylog
return (-I)**(s+1) * polylog(-s, I) + I**(s+1) * polylog(-s, -I)
def _eval_is_integer(self):
n = self.args[0]
if n.is_integer and n.is_nonnegative:
return True
def _eval_is_positive(self):
if self.args[0].is_nonnegative:
return True
def _eval_evalf(self, prec):
if not self.args[0].is_number:
return
s = self.args[0]._to_mpmath(prec+12)
with workprec(prec+12):
sp, cp = mp.sinpi(s/2), mp.cospi(s/2)
res = 2*mp.dirichlet(-s, (-sp, cp, sp, -cp))
return Expr._from_mpmath(res, prec)
#----------------------------------------------------------------------------#
# #
# Partition numbers #
# #
#----------------------------------------------------------------------------#
class partition(Function):
r"""
Partition numbers
The Partition numbers are a sequence of integers `p_n` that represent the
number of distinct ways of representing `n` as a sum of natural numbers
(with order irrelevant). The generating function for `p_n` is given by:
.. math:: \sum_{n=0}^\infty p_n x^n = \prod_{k=1}^\infty (1 - x^k)^{-1}
Examples
========
>>> from sympy import partition, Symbol
>>> [partition(n) for n in range(9)]
[1, 1, 2, 3, 5, 7, 11, 15, 22]
>>> n = Symbol('n', integer=True, negative=True)
>>> partition(n)
0
See Also
========
bell, bernoulli, catalan, euler, fibonacci, harmonic, lucas, genocchi, tribonacci
References
==========
.. [1] https://en.wikipedia.org/wiki/Partition_(number_theory%29
.. [2] https://en.wikipedia.org/wiki/Pentagonal_number_theorem
"""
is_integer = True
is_nonnegative = True
@classmethod
def eval(cls, n):
if n.is_integer is False:
raise TypeError("n should be an integer")
if n.is_negative is True:
return S.Zero
if n.is_zero is True or n is S.One:
return S.One
if n.is_Integer is True:
return S(_partition(as_int(n)))
def _eval_is_positive(self):
if self.args[0].is_nonnegative is True:
return True
class divisor_sigma(Function):
r"""
Calculate the divisor function `\sigma_k(n)` for positive integer n
``divisor_sigma(n, k)`` is equal to ``sum([x**k for x in divisors(n)])``
If n's prime factorization is:
.. math ::
n = \prod_{i=1}^\omega p_i^{m_i},
then
.. math ::
\sigma_k(n) = \prod_{i=1}^\omega (1+p_i^k+p_i^{2k}+\cdots
+ p_i^{m_ik}).
Examples
========
>>> from sympy.functions.combinatorial.numbers import divisor_sigma
>>> divisor_sigma(18, 0)
6
>>> divisor_sigma(39, 1)
56
>>> divisor_sigma(12, 2)
210
>>> divisor_sigma(37)
38
See Also
========
sympy.ntheory.factor_.divisor_count, totient, sympy.ntheory.factor_.divisors, sympy.ntheory.factor_.factorint
References
==========
.. [1] https://en.wikipedia.org/wiki/Divisor_function
"""
is_integer = True
is_positive = True
@classmethod
def eval(cls, n, k=S.One):
if n.is_integer is False:
raise TypeError("n should be an integer")
if n.is_positive is False:
raise ValueError("n should be a positive integer")
if k.is_integer is False:
raise TypeError("k should be an integer")
if k.is_nonnegative is False:
raise ValueError("k should be a nonnegative integer")
if n.is_prime is True:
return 1 + n**k
if n is S.One:
return S.One
if n.is_Integer is True:
if k.is_zero is True:
return Mul(*[e + 1 for e in factorint(n).values()])
if k.is_Integer is True:
return S(_divisor_sigma(as_int(n), as_int(k)))
if k.is_zero is False:
return Mul(*[cancel((p**(k*(e + 1)) - 1) / (p**k - 1)) for p, e in factorint(n).items()])
class udivisor_sigma(Function):
r"""
Calculate the unitary divisor function `\sigma_k^*(n)` for positive integer n
``udivisor_sigma(n, k)`` is equal to ``sum([x**k for x in udivisors(n)])``
If n's prime factorization is:
.. math ::
n = \prod_{i=1}^\omega p_i^{m_i},
then
.. math ::
\sigma_k^*(n) = \prod_{i=1}^\omega (1+ p_i^{m_ik}).
Parameters
==========
k : power of divisors in the sum
for k = 0, 1:
``udivisor_sigma(n, 0)`` is equal to ``udivisor_count(n)``
``udivisor_sigma(n, 1)`` is equal to ``sum(udivisors(n))``
Default for k is 1.
Examples
========
>>> from sympy.functions.combinatorial.numbers import udivisor_sigma
>>> udivisor_sigma(18, 0)
4
>>> udivisor_sigma(74, 1)
114
>>> udivisor_sigma(36, 3)
47450
>>> udivisor_sigma(111)
152
See Also
========
sympy.ntheory.factor_.divisor_count, totient, sympy.ntheory.factor_.divisors,
sympy.ntheory.factor_.udivisors, sympy.ntheory.factor_.udivisor_count, divisor_sigma,
sympy.ntheory.factor_.factorint
References
==========
.. [1] https://mathworld.wolfram.com/UnitaryDivisorFunction.html
"""
is_integer = True
is_positive = True
@classmethod
def eval(cls, n, k=S.One):
if n.is_integer is False:
raise TypeError("n should be an integer")
if n.is_positive is False:
raise ValueError("n should be a positive integer")
if k.is_integer is False:
raise TypeError("k should be an integer")
if k.is_nonnegative is False:
raise ValueError("k should be a nonnegative integer")
if n.is_prime is True:
return 1 + n**k
if n.is_Integer:
return Mul(*[1+p**(k*e) for p, e in factorint(n).items()])
class legendre_symbol(Function):
r"""
Returns the Legendre symbol `(a / p)`.
For an integer ``a`` and an odd prime ``p``, the Legendre symbol is
defined as
.. math ::
\genfrac(){}{}{a}{p} = \begin{cases}
0 & \text{if } p \text{ divides } a\\
1 & \text{if } a \text{ is a quadratic residue modulo } p\\
-1 & \text{if } a \text{ is a quadratic nonresidue modulo } p
\end{cases}
Examples
========
>>> from sympy.functions.combinatorial.numbers import legendre_symbol
>>> [legendre_symbol(i, 7) for i in range(7)]
[0, 1, 1, -1, 1, -1, -1]
>>> sorted(set([i**2 % 7 for i in range(7)]))
[0, 1, 2, 4]
See Also
========
sympy.ntheory.residue_ntheory.is_quad_residue, jacobi_symbol
"""
is_integer = True
is_prime = False
@classmethod
def eval(cls, a, p):
if a.is_integer is False:
raise TypeError("a should be an integer")
if p.is_integer is False:
raise TypeError("p should be an integer")
if p.is_prime is False or p.is_odd is False:
raise ValueError("p should be an odd prime integer")
if (a % p).is_zero is True:
return S.Zero
if a is S.One:
return S.One
if a.is_Integer is True and p.is_Integer is True:
return S(legendre(as_int(a), as_int(p)))
class jacobi_symbol(Function):
r"""
Returns the Jacobi symbol `(m / n)`.
For any integer ``m`` and any positive odd integer ``n`` the Jacobi symbol
is defined as the product of the Legendre symbols corresponding to the
prime factors of ``n``:
.. math ::
\genfrac(){}{}{m}{n} =
\genfrac(){}{}{m}{p^{1}}^{\alpha_1}
\genfrac(){}{}{m}{p^{2}}^{\alpha_2}
...
\genfrac(){}{}{m}{p^{k}}^{\alpha_k}
\text{ where } n =
p_1^{\alpha_1}
p_2^{\alpha_2}
...
p_k^{\alpha_k}
Like the Legendre symbol, if the Jacobi symbol `\genfrac(){}{}{m}{n} = -1`
then ``m`` is a quadratic nonresidue modulo ``n``.
But, unlike the Legendre symbol, if the Jacobi symbol
`\genfrac(){}{}{m}{n} = 1` then ``m`` may or may not be a quadratic residue
modulo ``n``.
Examples
========
>>> from sympy.functions.combinatorial.numbers import jacobi_symbol, legendre_symbol
>>> from sympy import S
>>> jacobi_symbol(45, 77)
-1
>>> jacobi_symbol(60, 121)
1
The relationship between the ``jacobi_symbol`` and ``legendre_symbol`` can
be demonstrated as follows:
>>> L = legendre_symbol
>>> S(45).factors()
{3: 2, 5: 1}
>>> jacobi_symbol(7, 45) == L(7, 3)**2 * L(7, 5)**1
True
See Also
========
sympy.ntheory.residue_ntheory.is_quad_residue, legendre_symbol
"""
is_integer = True
is_prime = False
@classmethod
def eval(cls, m, n):
if m.is_integer is False:
raise TypeError("m should be an integer")
if n.is_integer is False:
raise TypeError("n should be an integer")
if n.is_positive is False or n.is_odd is False:
raise ValueError("n should be an odd positive integer")
if m is S.One or n is S.One:
return S.One
if (m % n).is_zero is True:
return S.Zero
if m.is_Integer is True and n.is_Integer is True:
return S(jacobi(as_int(m), as_int(n)))
class kronecker_symbol(Function):
r"""
Returns the Kronecker symbol `(a / n)`.
Examples
========
>>> from sympy.functions.combinatorial.numbers import kronecker_symbol
>>> kronecker_symbol(45, 77)
-1
>>> kronecker_symbol(13, -120)
1
See Also
========
jacobi_symbol, legendre_symbol
References
==========
.. [1] https://en.wikipedia.org/wiki/Kronecker_symbol
"""
is_integer = True
is_prime = False
@classmethod
def eval(cls, a, n):
if a.is_integer is False:
raise TypeError("a should be an integer")
if n.is_integer is False:
raise TypeError("n should be an integer")
if a is S.One or n is S.One:
return S.One
if a.is_Integer is True and n.is_Integer is True:
return S(kronecker(as_int(a), as_int(n)))
class mobius(Function):
"""
Mobius function maps natural number to {-1, 0, 1}
It is defined as follows:
1) `1` if `n = 1`.
2) `0` if `n` has a squared prime factor.
3) `(-1)^k` if `n` is a square-free positive integer with `k`
number of prime factors.
It is an important multiplicative function in number theory
and combinatorics. It has applications in mathematical series,
algebraic number theory and also physics (Fermion operator has very
concrete realization with Mobius Function model).
Examples
========
>>> from sympy.functions.combinatorial.numbers import mobius
>>> mobius(13*7)
1
>>> mobius(1)
1
>>> mobius(13*7*5)
-1
>>> mobius(13**2)
0
Even in the case of a symbol, if it clearly contains a squared prime factor, it will be zero.
>>> from sympy import Symbol
>>> n = Symbol("n", integer=True, positive=True)
>>> mobius(4*n)
0
>>> mobius(n**2)
0
References
==========
.. [1] https://en.wikipedia.org/wiki/M%C3%B6bius_function
.. [2] Thomas Koshy "Elementary Number Theory with Applications"
.. [3] https://oeis.org/A008683
"""
is_integer = True
is_prime = False
@classmethod
def eval(cls, n):
if n.is_integer is False:
raise TypeError("n should be an integer")
if n.is_positive is False:
raise ValueError("n should be a positive integer")
if n.is_prime is True:
return S.NegativeOne
if n is S.One:
return S.One
result = None
for m, e in (_.as_base_exp() for _ in Mul.make_args(n)):
if m.is_integer is True and m.is_positive is True and \
e.is_integer is True and e.is_positive is True:
lt = is_lt(S.One, e) # 1 < e
if lt is True:
result = S.Zero
elif m.is_Integer is True:
factors = factorint(m)
if any(v > 1 for v in factors.values()):
result = S.Zero
elif lt is False:
s = S.NegativeOne if len(factors) % 2 else S.One
if result is None:
result = s
else:
result *= s
else:
return
return result
class primenu(Function):
r"""
Calculate the number of distinct prime factors for a positive integer n.
If n's prime factorization is:
.. math ::
n = \prod_{i=1}^k p_i^{m_i},
then ``primenu(n)`` or `\nu(n)` is:
.. math ::
\nu(n) = k.
Examples
========
>>> from sympy.functions.combinatorial.numbers import primenu
>>> primenu(1)
0
>>> primenu(30)
3
See Also
========
sympy.ntheory.factor_.factorint
References
==========
.. [1] https://mathworld.wolfram.com/PrimeFactor.html
.. [2] https://oeis.org/A001221
"""
is_integer = True
is_nonnegative = True
@classmethod
def eval(cls, n):
if n.is_integer is False:
raise TypeError("n should be an integer")
if n.is_positive is False:
raise ValueError("n should be a positive integer")
if n.is_prime is True:
return S.One
if n is S.One:
return S.Zero
if n.is_Integer is True:
return S(len(factorint(n)))
class primeomega(Function):
r"""
Calculate the number of prime factors counting multiplicities for a
positive integer n.
If n's prime factorization is:
.. math ::
n = \prod_{i=1}^k p_i^{m_i},
then ``primeomega(n)`` or `\Omega(n)` is:
.. math ::
\Omega(n) = \sum_{i=1}^k m_i.
Examples
========
>>> from sympy.functions.combinatorial.numbers import primeomega
>>> primeomega(1)
0
>>> primeomega(20)
3
See Also
========
sympy.ntheory.factor_.factorint
References
==========
.. [1] https://mathworld.wolfram.com/PrimeFactor.html
.. [2] https://oeis.org/A001222
"""
is_integer = True
is_nonnegative = True
@classmethod
def eval(cls, n):
if n.is_integer is False:
raise TypeError("n should be an integer")
if n.is_positive is False:
raise ValueError("n should be a positive integer")
if n.is_prime is True:
return S.One
if n is S.One:
return S.Zero
if n.is_Integer is True:
return S(sum(factorint(n).values()))
class totient(Function):
r"""
Calculate the Euler totient function phi(n)
``totient(n)`` or `\phi(n)` is the number of positive integers `\leq` n
that are relatively prime to n.
Examples
========
>>> from sympy.functions.combinatorial.numbers import totient
>>> totient(1)
1
>>> totient(25)
20
>>> totient(45) == totient(5)*totient(9)
True
See Also
========
sympy.ntheory.factor_.divisor_count
References
==========
.. [1] https://en.wikipedia.org/wiki/Euler%27s_totient_function
.. [2] https://mathworld.wolfram.com/TotientFunction.html
.. [3] https://oeis.org/A000010
"""
is_integer = True
is_positive = True
@classmethod
def eval(cls, n):
if n.is_integer is False:
raise TypeError("n should be an integer")
if n.is_positive is False:
raise ValueError("n should be a positive integer")
if n is S.One:
return S.One
if n.is_prime is True:
return n - 1
if isinstance(n, Dict):
return S(prod(p**(k-1)*(p-1) for p, k in n.items()))
if n.is_Integer is True:
return S(prod(p**(k-1)*(p-1) for p, k in factorint(n).items()))
class reduced_totient(Function):
r"""
Calculate the Carmichael reduced totient function lambda(n)
``reduced_totient(n)`` or `\lambda(n)` is the smallest m > 0 such that
`k^m \equiv 1 \mod n` for all k relatively prime to n.
Examples
========
>>> from sympy.functions.combinatorial.numbers import reduced_totient
>>> reduced_totient(1)
1
>>> reduced_totient(8)
2
>>> reduced_totient(30)
4
See Also
========
totient
References
==========
.. [1] https://en.wikipedia.org/wiki/Carmichael_function
.. [2] https://mathworld.wolfram.com/CarmichaelFunction.html
.. [3] https://oeis.org/A002322
"""
is_integer = True
is_positive = True
@classmethod
def eval(cls, n):
if n.is_integer is False:
raise TypeError("n should be an integer")
if n.is_positive is False:
raise ValueError("n should be a positive integer")
if n is S.One:
return S.One
if n.is_prime is True:
return n - 1
if isinstance(n, Dict):
t = 1
if 2 in n:
t = (1 << (n[2] - 2)) if 2 < n[2] else n[2]
return S(lcm(int(t), *(int(p-1)*int(p)**int(k-1) for p, k in n.items() if p != 2)))
if n.is_Integer is True:
n, t = remove(int(n), 2)
if not t:
t = 1
elif 2 < t:
t = 1 << (t - 2)
return S(lcm(t, *((p-1)*p**(k-1) for p, k in factorint(n).items())))
class primepi(Function):
r""" Represents the prime counting function pi(n) = the number
of prime numbers less than or equal to n.
Examples
========
>>> from sympy.functions.combinatorial.numbers import primepi
>>> from sympy import prime, prevprime, isprime
>>> primepi(25)
9
So there are 9 primes less than or equal to 25. Is 25 prime?
>>> isprime(25)
False
It is not. So the first prime less than 25 must be the
9th prime:
>>> prevprime(25) == prime(9)
True
See Also
========
sympy.ntheory.primetest.isprime : Test if n is prime
sympy.ntheory.generate.primerange : Generate all primes in a given range
sympy.ntheory.generate.prime : Return the nth prime
References
==========
.. [1] https://oeis.org/A000720
"""
is_integer = True
is_nonnegative = True
@classmethod
def eval(cls, n):
if n is S.Infinity:
return S.Infinity
if n is S.NegativeInfinity:
return S.Zero
if n.is_real is False:
raise TypeError("n should be a real")
if is_lt(n, S(2)) is True:
return S.Zero
try:
n = int(n)
except TypeError:
return
return S(_primepi(n))
#######################################################################
###
### Functions for enumerating partitions, permutations and combinations
###
#######################################################################
class _MultisetHistogram(tuple):
pass
_N = -1
_ITEMS = -2
_M = slice(None, _ITEMS)
def _multiset_histogram(n):
"""Return tuple used in permutation and combination counting. Input
is a dictionary giving items with counts as values or a sequence of
items (which need not be sorted).
The data is stored in a class deriving from tuple so it is easily
recognized and so it can be converted easily to a list.
"""
if isinstance(n, dict): # item: count
if not all(isinstance(v, int) and v >= 0 for v in n.values()):
raise ValueError
tot = sum(n.values())
items = sum(1 for k in n if n[k] > 0)
return _MultisetHistogram([n[k] for k in n if n[k] > 0] + [items, tot])
else:
n = list(n)
s = set(n)
lens = len(s)
lenn = len(n)
if lens == lenn:
n = [1]*lenn + [lenn, lenn]
return _MultisetHistogram(n)
m = dict(zip(s, range(lens)))
d = dict(zip(range(lens), (0,)*lens))
for i in n:
d[m[i]] += 1
return _multiset_histogram(d)
def nP(n, k=None, replacement=False):
"""Return the number of permutations of ``n`` items taken ``k`` at a time.
Possible values for ``n``:
integer - set of length ``n``
sequence - converted to a multiset internally
multiset - {element: multiplicity}
If ``k`` is None then the total of all permutations of length 0
through the number of items represented by ``n`` will be returned.
If ``replacement`` is True then a given item can appear more than once
in the ``k`` items. (For example, for 'ab' permutations of 2 would
include 'aa', 'ab', 'ba' and 'bb'.) The multiplicity of elements in
``n`` is ignored when ``replacement`` is True but the total number
of elements is considered since no element can appear more times than
the number of elements in ``n``.
Examples
========
>>> from sympy.functions.combinatorial.numbers import nP
>>> from sympy.utilities.iterables import multiset_permutations, multiset
>>> nP(3, 2)
6
>>> nP('abc', 2) == nP(multiset('abc'), 2) == 6
True
>>> nP('aab', 2)
3
>>> nP([1, 2, 2], 2)
3
>>> [nP(3, i) for i in range(4)]
[1, 3, 6, 6]
>>> nP(3) == sum(_)
True
When ``replacement`` is True, each item can have multiplicity
equal to the length represented by ``n``:
>>> nP('aabc', replacement=True)
121
>>> [len(list(multiset_permutations('aaaabbbbcccc', i))) for i in range(5)]
[1, 3, 9, 27, 81]
>>> sum(_)
121
See Also
========
sympy.utilities.iterables.multiset_permutations
References
==========
.. [1] https://en.wikipedia.org/wiki/Permutation
"""
try:
n = as_int(n)
except ValueError:
return Integer(_nP(_multiset_histogram(n), k, replacement))
return Integer(_nP(n, k, replacement))
@cacheit
def _nP(n, k=None, replacement=False):
if k == 0:
return 1
if isinstance(n, SYMPY_INTS): # n different items
# assert n >= 0
if k is None:
return sum(_nP(n, i, replacement) for i in range(n + 1))
elif replacement:
return n**k
elif k > n:
return 0
elif k == n:
return factorial(k)
elif k == 1:
return n
else:
# assert k >= 0
return _product(n - k + 1, n)
elif isinstance(n, _MultisetHistogram):
if k is None:
return sum(_nP(n, i, replacement) for i in range(n[_N] + 1))
elif replacement:
return n[_ITEMS]**k
elif k == n[_N]:
return factorial(k)/prod([factorial(i) for i in n[_M] if i > 1])
elif k > n[_N]:
return 0
elif k == 1:
return n[_ITEMS]
else:
# assert k >= 0
tot = 0
n = list(n)
for i in range(len(n[_M])):
if not n[i]:
continue
n[_N] -= 1
if n[i] == 1:
n[i] = 0
n[_ITEMS] -= 1
tot += _nP(_MultisetHistogram(n), k - 1)
n[_ITEMS] += 1
n[i] = 1
else:
n[i] -= 1
tot += _nP(_MultisetHistogram(n), k - 1)
n[i] += 1
n[_N] += 1
return tot
@cacheit
def _AOP_product(n):
"""for n = (m1, m2, .., mk) return the coefficients of the polynomial,
prod(sum(x**i for i in range(nj + 1)) for nj in n); i.e. the coefficients
of the product of AOPs (all-one polynomials) or order given in n. The
resulting coefficient corresponding to x**r is the number of r-length
combinations of sum(n) elements with multiplicities given in n.
The coefficients are given as a default dictionary (so if a query is made
for a key that is not present, 0 will be returned).
Examples
========
>>> from sympy.functions.combinatorial.numbers import _AOP_product
>>> from sympy.abc import x
>>> n = (2, 2, 3) # e.g. aabbccc
>>> prod = ((x**2 + x + 1)*(x**2 + x + 1)*(x**3 + x**2 + x + 1)).expand()
>>> c = _AOP_product(n); dict(c)
{0: 1, 1: 3, 2: 6, 3: 8, 4: 8, 5: 6, 6: 3, 7: 1}
>>> [c[i] for i in range(8)] == [prod.coeff(x, i) for i in range(8)]
True
The generating poly used here is the same as that listed in
https://tinyurl.com/cep849r, but in a refactored form.
"""
n = list(n)
ord = sum(n)
need = (ord + 2)//2
rv = [1]*(n.pop() + 1)
rv.extend((0,) * (need - len(rv)))
rv = rv[:need]
while n:
ni = n.pop()
N = ni + 1
was = rv[:]
for i in range(1, min(N, len(rv))):
rv[i] += rv[i - 1]
for i in range(N, need):
rv[i] += rv[i - 1] - was[i - N]
rev = list(reversed(rv))
if ord % 2:
rv = rv + rev
else:
rv[-1:] = rev
d = defaultdict(int)
for i, r in enumerate(rv):
d[i] = r
return d
def nC(n, k=None, replacement=False):
"""Return the number of combinations of ``n`` items taken ``k`` at a time.
Possible values for ``n``:
integer - set of length ``n``
sequence - converted to a multiset internally
multiset - {element: multiplicity}
If ``k`` is None then the total of all combinations of length 0
through the number of items represented in ``n`` will be returned.
If ``replacement`` is True then a given item can appear more than once
in the ``k`` items. (For example, for 'ab' sets of 2 would include 'aa',
'ab', and 'bb'.) The multiplicity of elements in ``n`` is ignored when
``replacement`` is True but the total number of elements is considered
since no element can appear more times than the number of elements in
``n``.
Examples
========
>>> from sympy.functions.combinatorial.numbers import nC
>>> from sympy.utilities.iterables import multiset_combinations
>>> nC(3, 2)
3
>>> nC('abc', 2)
3
>>> nC('aab', 2)
2
When ``replacement`` is True, each item can have multiplicity
equal to the length represented by ``n``:
>>> nC('aabc', replacement=True)
35
>>> [len(list(multiset_combinations('aaaabbbbcccc', i))) for i in range(5)]
[1, 3, 6, 10, 15]
>>> sum(_)
35
If there are ``k`` items with multiplicities ``m_1, m_2, ..., m_k``
then the total of all combinations of length 0 through ``k`` is the
product, ``(m_1 + 1)*(m_2 + 1)*...*(m_k + 1)``. When the multiplicity
of each item is 1 (i.e., k unique items) then there are 2**k
combinations. For example, if there are 4 unique items, the total number
of combinations is 16:
>>> sum(nC(4, i) for i in range(5))
16
See Also
========
sympy.utilities.iterables.multiset_combinations
References
==========
.. [1] https://en.wikipedia.org/wiki/Combination
.. [2] https://tinyurl.com/cep849r
"""
if isinstance(n, SYMPY_INTS):
if k is None:
if not replacement:
return 2**n
return sum(nC(n, i, replacement) for i in range(n + 1))
if k < 0:
raise ValueError("k cannot be negative")
if replacement:
return binomial(n + k - 1, k)
return binomial(n, k)
if isinstance(n, _MultisetHistogram):
N = n[_N]
if k is None:
if not replacement:
return prod(m + 1 for m in n[_M])
return sum(nC(n, i, replacement) for i in range(N + 1))
elif replacement:
return nC(n[_ITEMS], k, replacement)
# assert k >= 0
elif k in (1, N - 1):
return n[_ITEMS]
elif k in (0, N):
return 1
return _AOP_product(tuple(n[_M]))[k]
else:
return nC(_multiset_histogram(n), k, replacement)
def _eval_stirling1(n, k):
if n == k == 0:
return S.One
if 0 in (n, k):
return S.Zero
# some special values
if n == k:
return S.One
elif k == n - 1:
return binomial(n, 2)
elif k == n - 2:
return (3*n - 1)*binomial(n, 3)/4
elif k == n - 3:
return binomial(n, 2)*binomial(n, 4)
return _stirling1(n, k)
@cacheit
def _stirling1(n, k):
row = [0, 1]+[0]*(k-1) # for n = 1
for i in range(2, n+1):
for j in range(min(k,i), 0, -1):
row[j] = (i-1) * row[j] + row[j-1]
return Integer(row[k])
def _eval_stirling2(n, k):
if n == k == 0:
return S.One
if 0 in (n, k):
return S.Zero
# some special values
if n == k:
return S.One
elif k == n - 1:
return binomial(n, 2)
elif k == 1:
return S.One
elif k == 2:
return Integer(2**(n - 1) - 1)
return _stirling2(n, k)
@cacheit
def _stirling2(n, k):
row = [0, 1]+[0]*(k-1) # for n = 1
for i in range(2, n+1):
for j in range(min(k,i), 0, -1):
row[j] = j * row[j] + row[j-1]
return Integer(row[k])
def stirling(n, k, d=None, kind=2, signed=False):
r"""Return Stirling number $S(n, k)$ of the first or second (default) kind.
The sum of all Stirling numbers of the second kind for $k = 1$
through $n$ is ``bell(n)``. The recurrence relationship for these numbers
is:
.. math :: {0 \brace 0} = 1; {n \brace 0} = {0 \brace k} = 0;
.. math :: {{n+1} \brace k} = j {n \brace k} + {n \brace {k-1}}
where $j$ is:
$n$ for Stirling numbers of the first kind,
$-n$ for signed Stirling numbers of the first kind,
$k$ for Stirling numbers of the second kind.
The first kind of Stirling number counts the number of permutations of
``n`` distinct items that have ``k`` cycles; the second kind counts the
ways in which ``n`` distinct items can be partitioned into ``k`` parts.
If ``d`` is given, the "reduced Stirling number of the second kind" is
returned: $S^{d}(n, k) = S(n - d + 1, k - d + 1)$ with $n \ge k \ge d$.
(This counts the ways to partition $n$ consecutive integers into $k$
groups with no pairwise difference less than $d$. See example below.)
To obtain the signed Stirling numbers of the first kind, use keyword
``signed=True``. Using this keyword automatically sets ``kind`` to 1.
Examples
========
>>> from sympy.functions.combinatorial.numbers import stirling, bell
>>> from sympy.combinatorics import Permutation
>>> from sympy.utilities.iterables import multiset_partitions, permutations
First kind (unsigned by default):
>>> [stirling(6, i, kind=1) for i in range(7)]
[0, 120, 274, 225, 85, 15, 1]
>>> perms = list(permutations(range(4)))
>>> [sum(Permutation(p).cycles == i for p in perms) for i in range(5)]
[0, 6, 11, 6, 1]
>>> [stirling(4, i, kind=1) for i in range(5)]
[0, 6, 11, 6, 1]
First kind (signed):
>>> [stirling(4, i, signed=True) for i in range(5)]
[0, -6, 11, -6, 1]
Second kind:
>>> [stirling(10, i) for i in range(12)]
[0, 1, 511, 9330, 34105, 42525, 22827, 5880, 750, 45, 1, 0]
>>> sum(_) == bell(10)
True
>>> len(list(multiset_partitions(range(4), 2))) == stirling(4, 2)
True
Reduced second kind:
>>> from sympy import subsets, oo
>>> def delta(p):
... if len(p) == 1:
... return oo
... return min(abs(i[0] - i[1]) for i in subsets(p, 2))
>>> parts = multiset_partitions(range(5), 3)
>>> d = 2
>>> sum(1 for p in parts if all(delta(i) >= d for i in p))
7
>>> stirling(5, 3, 2)
7
See Also
========
sympy.utilities.iterables.multiset_partitions
References
==========
.. [1] https://en.wikipedia.org/wiki/Stirling_numbers_of_the_first_kind
.. [2] https://en.wikipedia.org/wiki/Stirling_numbers_of_the_second_kind
"""
# TODO: make this a class like bell()
n = as_int(n)
k = as_int(k)
if n < 0:
raise ValueError('n must be nonnegative')
if k > n:
return S.Zero
if d:
# assert k >= d
# kind is ignored -- only kind=2 is supported
return _eval_stirling2(n - d + 1, k - d + 1)
elif signed:
# kind is ignored -- only kind=1 is supported
return S.NegativeOne**(n - k)*_eval_stirling1(n, k)
if kind == 1:
return _eval_stirling1(n, k)
elif kind == 2:
return _eval_stirling2(n, k)
else:
raise ValueError('kind must be 1 or 2, not %s' % k)
@cacheit
def _nT(n, k):
"""Return the partitions of ``n`` items into ``k`` parts. This
is used by ``nT`` for the case when ``n`` is an integer."""
# really quick exits
if k > n or k < 0:
return 0
if k in (1, n):
return 1
if k == 0:
return 0
# exits that could be done below but this is quicker
if k == 2:
return n//2
d = n - k
if d <= 3:
return d
# quick exit
if 3*k >= n: # or, equivalently, 2*k >= d
# all the information needed in this case
# will be in the cache needed to calculate
# partition(d), so...
# update cache
tot = _partition_rec(d)
# and correct for values not needed
if d - k > 0:
tot -= sum(_partition_rec.fetch_item(slice(d - k)))
return tot
# regular exit
# nT(n, k) = Sum(nT(n - k, m), (m, 1, k));
# calculate needed nT(i, j) values
p = [1]*d
for i in range(2, k + 1):
for m in range(i + 1, d):
p[m] += p[m - i]
d -= 1
# if p[0] were appended to the end of p then the last
# k values of p are the nT(n, j) values for 0 < j < k in reverse
# order p[-1] = nT(n, 1), p[-2] = nT(n, 2), etc.... Instead of
# putting the 1 from p[0] there, however, it is simply added to
# the sum below which is valid for 1 < k <= n//2
return (1 + sum(p[1 - k:]))
def nT(n, k=None):
"""Return the number of ``k``-sized partitions of ``n`` items.
Possible values for ``n``:
integer - ``n`` identical items
sequence - converted to a multiset internally
multiset - {element: multiplicity}
Note: the convention for ``nT`` is different than that of ``nC`` and
``nP`` in that
here an integer indicates ``n`` *identical* items instead of a set of
length ``n``; this is in keeping with the ``partitions`` function which
treats its integer-``n`` input like a list of ``n`` 1s. One can use
``range(n)`` for ``n`` to indicate ``n`` distinct items.
If ``k`` is None then the total number of ways to partition the elements
represented in ``n`` will be returned.
Examples
========
>>> from sympy.functions.combinatorial.numbers import nT
Partitions of the given multiset:
>>> [nT('aabbc', i) for i in range(1, 7)]
[1, 8, 11, 5, 1, 0]
>>> nT('aabbc') == sum(_)
True
>>> [nT("mississippi", i) for i in range(1, 12)]
[1, 74, 609, 1521, 1768, 1224, 579, 197, 50, 9, 1]
Partitions when all items are identical:
>>> [nT(5, i) for i in range(1, 6)]
[1, 2, 2, 1, 1]
>>> nT('1'*5) == sum(_)
True
When all items are different:
>>> [nT(range(5), i) for i in range(1, 6)]
[1, 15, 25, 10, 1]
>>> nT(range(5)) == sum(_)
True
Partitions of an integer expressed as a sum of positive integers:
>>> from sympy import partition
>>> partition(4)
5
>>> nT(4, 1) + nT(4, 2) + nT(4, 3) + nT(4, 4)
5
>>> nT('1'*4)
5
See Also
========
sympy.utilities.iterables.partitions
sympy.utilities.iterables.multiset_partitions
sympy.functions.combinatorial.numbers.partition
References
==========
.. [1] https://web.archive.org/web/20210507012732/https://teaching.csse.uwa.edu.au/units/CITS7209/partition.pdf
"""
if isinstance(n, SYMPY_INTS):
# n identical items
if k is None:
return partition(n)
if isinstance(k, SYMPY_INTS):
n = as_int(n)
k = as_int(k)
return Integer(_nT(n, k))
if not isinstance(n, _MultisetHistogram):
try:
# if n contains hashable items there is some
# quick handling that can be done
u = len(set(n))
if u <= 1:
return nT(len(n), k)
elif u == len(n):
n = range(u)
raise TypeError
except TypeError:
n = _multiset_histogram(n)
N = n[_N]
if k is None and N == 1:
return 1
if k in (1, N):
return 1
if k == 2 or N == 2 and k is None:
m, r = divmod(N, 2)
rv = sum(nC(n, i) for i in range(1, m + 1))
if not r:
rv -= nC(n, m)//2
if k is None:
rv += 1 # for k == 1
return rv
if N == n[_ITEMS]:
# all distinct
if k is None:
return bell(N)
return stirling(N, k)
m = MultisetPartitionTraverser()
if k is None:
return m.count_partitions(n[_M])
# MultisetPartitionTraverser does not have a range-limited count
# method, so need to enumerate and count
tot = 0
for discard in m.enum_range(n[_M], k-1, k):
tot += 1
return tot
#-----------------------------------------------------------------------------#
# #
# Motzkin numbers #
# #
#-----------------------------------------------------------------------------#
class motzkin(Function):
"""
The nth Motzkin number is the number
of ways of drawing non-intersecting chords
between n points on a circle (not necessarily touching
every point by a chord). The Motzkin numbers are named
after Theodore Motzkin and have diverse applications
in geometry, combinatorics and number theory.
Motzkin numbers are the integer sequence defined by the
initial terms `M_0 = 1`, `M_1 = 1` and the two-term recurrence relation
`M_n = \frac{2*n + 1}{n + 2} * M_{n-1} + \frac{3n - 3}{n + 2} * M_{n-2}`.
Examples
========
>>> from sympy import motzkin
>>> motzkin.is_motzkin(5)
False
>>> motzkin.find_motzkin_numbers_in_range(2,300)
[2, 4, 9, 21, 51, 127]
>>> motzkin.find_motzkin_numbers_in_range(2,900)
[2, 4, 9, 21, 51, 127, 323, 835]
>>> motzkin.find_first_n_motzkins(10)
[1, 1, 2, 4, 9, 21, 51, 127, 323, 835]
References
==========
.. [1] https://en.wikipedia.org/wiki/Motzkin_number
.. [2] https://mathworld.wolfram.com/MotzkinNumber.html
"""
@staticmethod
def is_motzkin(n):
try:
n = as_int(n)
except ValueError:
return False
if n > 0:
if n in (1, 2):
return True
tn1 = 1
tn = 2
i = 3
while tn < n:
a = ((2*i + 1)*tn + (3*i - 3)*tn1)/(i + 2)
i += 1
tn1 = tn
tn = a
if tn == n:
return True
else:
return False
else:
return False
@staticmethod
def find_motzkin_numbers_in_range(x, y):
if 0 <= x <= y:
motzkins = []
if x <= 1 <= y:
motzkins.append(1)
tn1 = 1
tn = 2
i = 3
while tn <= y:
if tn >= x:
motzkins.append(tn)
a = ((2*i + 1)*tn + (3*i - 3)*tn1)/(i + 2)
i += 1
tn1 = tn
tn = int(a)
return motzkins
else:
raise ValueError('The provided range is not valid. This condition should satisfy x <= y')
@staticmethod
def find_first_n_motzkins(n):
try:
n = as_int(n)
except ValueError:
raise ValueError('The provided number must be a positive integer')
if n < 0:
raise ValueError('The provided number must be a positive integer')
motzkins = [1]
if n >= 1:
motzkins.append(1)
tn1 = 1
tn = 2
i = 3
while i <= n:
motzkins.append(tn)
a = ((2*i + 1)*tn + (3*i - 3)*tn1)/(i + 2)
i += 1
tn1 = tn
tn = int(a)
return motzkins
@staticmethod
@recurrence_memo([S.One, S.One])
def _motzkin(n, prev):
return ((2*n + 1)*prev[-1] + (3*n - 3)*prev[-2]) // (n + 2)
@classmethod
def eval(cls, n):
try:
n = as_int(n)
except ValueError:
raise ValueError('The provided number must be a positive integer')
if n < 0:
raise ValueError('The provided number must be a positive integer')
return Integer(cls._motzkin(n - 1))
def nD(i=None, brute=None, *, n=None, m=None):
"""return the number of derangements for: ``n`` unique items, ``i``
items (as a sequence or multiset), or multiplicities, ``m`` given
as a sequence or multiset.
Examples
========
>>> from sympy.utilities.iterables import generate_derangements as enum
>>> from sympy.functions.combinatorial.numbers import nD
A derangement ``d`` of sequence ``s`` has all ``d[i] != s[i]``:
>>> set([''.join(i) for i in enum('abc')])
{'bca', 'cab'}
>>> nD('abc')
2
Input as iterable or dictionary (multiset form) is accepted:
>>> assert nD([1, 2, 2, 3, 3, 3]) == nD({1: 1, 2: 2, 3: 3})
By default, a brute-force enumeration and count of multiset permutations
is only done if there are fewer than 9 elements. There may be cases when
there is high multiplicity with few unique elements that will benefit
from a brute-force enumeration, too. For this reason, the `brute`
keyword (default None) is provided. When False, the brute-force
enumeration will never be used. When True, it will always be used.
>>> nD('1111222233', brute=True)
44
For convenience, one may specify ``n`` distinct items using the
``n`` keyword:
>>> assert nD(n=3) == nD('abc') == 2
Since the number of derangments depends on the multiplicity of the
elements and not the elements themselves, it may be more convenient
to give a list or multiset of multiplicities using keyword ``m``:
>>> assert nD('abc') == nD(m=(1,1,1)) == nD(m={1:3}) == 2
"""
from sympy.integrals.integrals import integrate
from sympy.functions.special.polynomials import laguerre
from sympy.abc import x
def ok(x):
if not isinstance(x, SYMPY_INTS):
raise TypeError('expecting integer values')
if x < 0:
raise ValueError('value must not be negative')
return True
if (i, n, m).count(None) != 2:
raise ValueError('enter only 1 of i, n, or m')
if i is not None:
if isinstance(i, SYMPY_INTS):
raise TypeError('items must be a list or dictionary')
if not i:
return S.Zero
if type(i) is not dict:
s = list(i)
ms = multiset(s)
elif type(i) is dict:
all(ok(_) for _ in i.values())
ms = {k: v for k, v in i.items() if v}
s = None
if not ms:
return S.Zero
N = sum(ms.values())
counts = multiset(ms.values())
nkey = len(ms)
elif n is not None:
ok(n)
if not n:
return S.Zero
return subfactorial(n)
elif m is not None:
if isinstance(m, dict):
all(ok(i) and ok(j) for i, j in m.items())
counts = {k: v for k, v in m.items() if k*v}
elif iterable(m) or isinstance(m, str):
m = list(m)
all(ok(i) for i in m)
counts = multiset([i for i in m if i])
else:
raise TypeError('expecting iterable')
if not counts:
return S.Zero
N = sum(k*v for k, v in counts.items())
nkey = sum(counts.values())
s = None
big = int(max(counts))
if big == 1: # no repetition
return subfactorial(nkey)
nval = len(counts)
if big*2 > N:
return S.Zero
if big*2 == N:
if nkey == 2 and nval == 1:
return S.One # aaabbb
if nkey - 1 == big: # one element repeated
return factorial(big) # e.g. abc part of abcddd
if N < 9 and brute is None or brute:
# for all possibilities, this was found to be faster
if s is None:
s = []
i = 0
for m, v in counts.items():
for j in range(v):
s.extend([i]*m)
i += 1
return Integer(sum(1 for i in multiset_derangements(s)))
from sympy.functions.elementary.exponential import exp
return Integer(abs(integrate(exp(-x)*Mul(*[
laguerre(i, x)**m for i, m in counts.items()]), (x, 0, oo))))
PK ]ZZZ��A2 2 & sympy/functions/elementary/__init__.py# Stub __init__.py for sympy.functions.elementary
PK ]ZZZԴ]g g 4 sympy/functions/elementary/_trigonometric_special.pyr"""A module for special angle formulas for trigonometric functions
TODO
====
This module should be developed in the future to contain direct square root
representation of
.. math
F(\frac{n}{m} \pi)
for every
- $m \in \{ 3, 5, 17, 257, 65537 \}$
- $n \in \mathbb{N}$, $0 \le n < m$
- $F \in \{\sin, \cos, \tan, \csc, \sec, \cot\}$
Without multi-step rewrites
(e.g. $\tan \to \cos/\sin \to \cos/\sqrt \to \ sqrt$)
or using chebyshev identities
(e.g. $\cos \to \cos + \cos^2 + \cdots \to \sqrt{} + \sqrt{}^2 + \cdots $),
which are trivial to implement in sympy,
and had used to give overly complicated expressions.
The reference can be found below, if anyone may need help implementing them.
References
==========
.. [*] Gottlieb, Christian. (1999). The Simple and straightforward construction
of the regular 257-gon. The Mathematical Intelligencer. 21. 31-37.
10.1007/BF03024829.
.. [*] https://resources.wolframcloud.com/FunctionRepository/resources/Cos2PiOverFermatPrime
"""
from __future__ import annotations
from typing import Callable
from functools import reduce
from sympy.core.expr import Expr
from sympy.core.singleton import S
from sympy.core.intfunc import igcdex
from sympy.core.numbers import Integer
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.core.cache import cacheit
def migcdex(*x: int) -> tuple[tuple[int, ...], int]:
r"""Compute extended gcd for multiple integers.
Explanation
===========
Given the integers $x_1, \cdots, x_n$ and
an extended gcd for multiple arguments are defined as a solution
$(y_1, \cdots, y_n), g$ for the diophantine equation
$x_1 y_1 + \cdots + x_n y_n = g$ such that
$g = \gcd(x_1, \cdots, x_n)$.
Examples
========
>>> from sympy.functions.elementary._trigonometric_special import migcdex
>>> migcdex()
((), 0)
>>> migcdex(4)
((1,), 4)
>>> migcdex(4, 6)
((-1, 1), 2)
>>> migcdex(6, 10, 15)
((1, 1, -1), 1)
"""
if not x:
return (), 0
if len(x) == 1:
return (1,), x[0]
if len(x) == 2:
u, v, h = igcdex(x[0], x[1])
return (u, v), h
y, g = migcdex(*x[1:])
u, v, h = igcdex(x[0], g)
return (u, *(v * i for i in y)), h
def ipartfrac(*denoms: int) -> tuple[int, ...]:
r"""Compute the partial fraction decomposition.
Explanation
===========
Given a rational number $\frac{1}{q_1 \cdots q_n}$ where all
$q_1, \cdots, q_n$ are pairwise coprime,
A partial fraction decomposition is defined as
.. math::
\frac{1}{q_1 \cdots q_n} = \frac{p_1}{q_1} + \cdots + \frac{p_n}{q_n}
And it can be derived from solving the following diophantine equation for
the $p_1, \cdots, p_n$
.. math::
1 = p_1 \prod_{i \ne 1}q_i + \cdots + p_n \prod_{i \ne n}q_i
Where $q_1, \cdots, q_n$ being pairwise coprime implies
$\gcd(\prod_{i \ne 1}q_i, \cdots, \prod_{i \ne n}q_i) = 1$,
which guarantees the existence of the solution.
It is sufficient to compute partial fraction decomposition only
for numerator $1$ because partial fraction decomposition for any
$\frac{n}{q_1 \cdots q_n}$ can be easily computed by multiplying
the result by $n$ afterwards.
Parameters
==========
denoms : int
The pairwise coprime integer denominators $q_i$ which defines the
rational number $\frac{1}{q_1 \cdots q_n}$
Returns
=======
tuple[int, ...]
The list of numerators which semantically corresponds to $p_i$ of the
partial fraction decomposition
$\frac{1}{q_1 \cdots q_n} = \frac{p_1}{q_1} + \cdots + \frac{p_n}{q_n}$
Examples
========
>>> from sympy import Rational, Mul
>>> from sympy.functions.elementary._trigonometric_special import ipartfrac
>>> denoms = 2, 3, 5
>>> numers = ipartfrac(2, 3, 5)
>>> numers
(1, 7, -14)
>>> Rational(1, Mul(*denoms))
1/30
>>> out = 0
>>> for n, d in zip(numers, denoms):
... out += Rational(n, d)
>>> out
1/30
"""
if not denoms:
return ()
def mul(x: int, y: int) -> int:
return x * y
denom = reduce(mul, denoms)
a = [denom // x for x in denoms]
h, _ = migcdex(*a)
return h
def fermat_coords(n: int) -> list[int] | None:
"""If n can be factored in terms of Fermat primes with
multiplicity of each being 1, return those primes, else
None
"""
primes = []
for p in [3, 5, 17, 257, 65537]:
quotient, remainder = divmod(n, p)
if remainder == 0:
n = quotient
primes.append(p)
if n == 1:
return primes
return None
@cacheit
def cos_3() -> Expr:
r"""Computes $\cos \frac{\pi}{3}$ in square roots"""
return S.Half
@cacheit
def cos_5() -> Expr:
r"""Computes $\cos \frac{\pi}{5}$ in square roots"""
return (sqrt(5) + 1) / 4
@cacheit
def cos_17() -> Expr:
r"""Computes $\cos \frac{\pi}{17}$ in square roots"""
return sqrt(
(15 + sqrt(17)) / 32 + sqrt(2) * (sqrt(17 - sqrt(17)) +
sqrt(sqrt(2) * (-8 * sqrt(17 + sqrt(17)) - (1 - sqrt(17))
* sqrt(17 - sqrt(17))) + 6 * sqrt(17) + 34)) / 32)
@cacheit
def cos_257() -> Expr:
r"""Computes $\cos \frac{\pi}{257}$ in square roots
References
==========
.. [*] https://math.stackexchange.com/questions/516142/how-does-cos2-pi-257-look-like-in-real-radicals
.. [*] https://r-knott.surrey.ac.uk/Fibonacci/simpleTrig.html
"""
def f1(a: Expr, b: Expr) -> tuple[Expr, Expr]:
return (a + sqrt(a**2 + b)) / 2, (a - sqrt(a**2 + b)) / 2
def f2(a: Expr, b: Expr) -> Expr:
return (a - sqrt(a**2 + b))/2
t1, t2 = f1(S.NegativeOne, Integer(256))
z1, z3 = f1(t1, Integer(64))
z2, z4 = f1(t2, Integer(64))
y1, y5 = f1(z1, 4*(5 + t1 + 2*z1))
y6, y2 = f1(z2, 4*(5 + t2 + 2*z2))
y3, y7 = f1(z3, 4*(5 + t1 + 2*z3))
y8, y4 = f1(z4, 4*(5 + t2 + 2*z4))
x1, x9 = f1(y1, -4*(t1 + y1 + y3 + 2*y6))
x2, x10 = f1(y2, -4*(t2 + y2 + y4 + 2*y7))
x3, x11 = f1(y3, -4*(t1 + y3 + y5 + 2*y8))
x4, x12 = f1(y4, -4*(t2 + y4 + y6 + 2*y1))
x5, x13 = f1(y5, -4*(t1 + y5 + y7 + 2*y2))
x6, x14 = f1(y6, -4*(t2 + y6 + y8 + 2*y3))
x15, x7 = f1(y7, -4*(t1 + y7 + y1 + 2*y4))
x8, x16 = f1(y8, -4*(t2 + y8 + y2 + 2*y5))
v1 = f2(x1, -4*(x1 + x2 + x3 + x6))
v2 = f2(x2, -4*(x2 + x3 + x4 + x7))
v3 = f2(x8, -4*(x8 + x9 + x10 + x13))
v4 = f2(x9, -4*(x9 + x10 + x11 + x14))
v5 = f2(x10, -4*(x10 + x11 + x12 + x15))
v6 = f2(x16, -4*(x16 + x1 + x2 + x5))
u1 = -f2(-v1, -4*(v2 + v3))
u2 = -f2(-v4, -4*(v5 + v6))
w1 = -2*f2(-u1, -4*u2)
return sqrt(sqrt(2)*sqrt(w1 + 4)/8 + S.Half)
def cos_table() -> dict[int, Callable[[], Expr]]:
r"""Lazily evaluated table for $\cos \frac{\pi}{n}$ in square roots for
$n \in \{3, 5, 17, 257, 65537\}$.
Notes
=====
65537 is the only other known Fermat prime and it is nearly impossible to
build in the current SymPy due to performance issues.
References
==========
https://r-knott.surrey.ac.uk/Fibonacci/simpleTrig.html
"""
return {
3: cos_3,
5: cos_5,
17: cos_17,
257: cos_257
}
PK ]ZZZM�� � ' sympy/functions/elementary/complexes.pyfrom typing import Tuple as tTuple
from sympy.core import S, Add, Mul, sympify, Symbol, Dummy, Basic
from sympy.core.expr import Expr
from sympy.core.exprtools import factor_terms
from sympy.core.function import (Function, Derivative, ArgumentIndexError,
AppliedUndef, expand_mul)
from sympy.core.logic import fuzzy_not, fuzzy_or
from sympy.core.numbers import pi, I, oo
from sympy.core.power import Pow
from sympy.core.relational import Eq
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.elementary.piecewise import Piecewise
###############################################################################
######################### REAL and IMAGINARY PARTS ############################
###############################################################################
class re(Function):
"""
Returns real part of expression. This function performs only
elementary analysis and so it will fail to decompose properly
more complicated expressions. If completely simplified result
is needed then use ``Basic.as_real_imag()`` or perform complex
expansion on instance of this function.
Examples
========
>>> from sympy import re, im, I, E, symbols
>>> x, y = symbols('x y', real=True)
>>> re(2*E)
2*E
>>> re(2*I + 17)
17
>>> re(2*I)
0
>>> re(im(x) + x*I + 2)
2
>>> re(5 + I + 2)
7
Parameters
==========
arg : Expr
Real or complex expression.
Returns
=======
expr : Expr
Real part of expression.
See Also
========
im
"""
args: tTuple[Expr]
is_extended_real = True
unbranched = True # implicitly works on the projection to C
_singularities = True # non-holomorphic
@classmethod
def eval(cls, arg):
if arg is S.NaN:
return S.NaN
elif arg is S.ComplexInfinity:
return S.NaN
elif arg.is_extended_real:
return arg
elif arg.is_imaginary or (I*arg).is_extended_real:
return S.Zero
elif arg.is_Matrix:
return arg.as_real_imag()[0]
elif arg.is_Function and isinstance(arg, conjugate):
return re(arg.args[0])
else:
included, reverted, excluded = [], [], []
args = Add.make_args(arg)
for term in args:
coeff = term.as_coefficient(I)
if coeff is not None:
if not coeff.is_extended_real:
reverted.append(coeff)
elif not term.has(I) and term.is_extended_real:
excluded.append(term)
else:
# Try to do some advanced expansion. If
# impossible, don't try to do re(arg) again
# (because this is what we are trying to do now).
real_imag = term.as_real_imag(ignore=arg)
if real_imag:
excluded.append(real_imag[0])
else:
included.append(term)
if len(args) != len(included):
a, b, c = (Add(*xs) for xs in [included, reverted, excluded])
return cls(a) - im(b) + c
def as_real_imag(self, deep=True, **hints):
"""
Returns the real number with a zero imaginary part.
"""
return (self, S.Zero)
def _eval_derivative(self, x):
if x.is_extended_real or self.args[0].is_extended_real:
return re(Derivative(self.args[0], x, evaluate=True))
if x.is_imaginary or self.args[0].is_imaginary:
return -I \
* im(Derivative(self.args[0], x, evaluate=True))
def _eval_rewrite_as_im(self, arg, **kwargs):
return self.args[0] - I*im(self.args[0])
def _eval_is_algebraic(self):
return self.args[0].is_algebraic
def _eval_is_zero(self):
# is_imaginary implies nonzero
return fuzzy_or([self.args[0].is_imaginary, self.args[0].is_zero])
def _eval_is_finite(self):
if self.args[0].is_finite:
return True
def _eval_is_complex(self):
if self.args[0].is_finite:
return True
class im(Function):
"""
Returns imaginary part of expression. This function performs only
elementary analysis and so it will fail to decompose properly more
complicated expressions. If completely simplified result is needed then
use ``Basic.as_real_imag()`` or perform complex expansion on instance of
this function.
Examples
========
>>> from sympy import re, im, E, I
>>> from sympy.abc import x, y
>>> im(2*E)
0
>>> im(2*I + 17)
2
>>> im(x*I)
re(x)
>>> im(re(x) + y)
im(y)
>>> im(2 + 3*I)
3
Parameters
==========
arg : Expr
Real or complex expression.
Returns
=======
expr : Expr
Imaginary part of expression.
See Also
========
re
"""
args: tTuple[Expr]
is_extended_real = True
unbranched = True # implicitly works on the projection to C
_singularities = True # non-holomorphic
@classmethod
def eval(cls, arg):
if arg is S.NaN:
return S.NaN
elif arg is S.ComplexInfinity:
return S.NaN
elif arg.is_extended_real:
return S.Zero
elif arg.is_imaginary or (I*arg).is_extended_real:
return -I * arg
elif arg.is_Matrix:
return arg.as_real_imag()[1]
elif arg.is_Function and isinstance(arg, conjugate):
return -im(arg.args[0])
else:
included, reverted, excluded = [], [], []
args = Add.make_args(arg)
for term in args:
coeff = term.as_coefficient(I)
if coeff is not None:
if not coeff.is_extended_real:
reverted.append(coeff)
else:
excluded.append(coeff)
elif term.has(I) or not term.is_extended_real:
# Try to do some advanced expansion. If
# impossible, don't try to do im(arg) again
# (because this is what we are trying to do now).
real_imag = term.as_real_imag(ignore=arg)
if real_imag:
excluded.append(real_imag[1])
else:
included.append(term)
if len(args) != len(included):
a, b, c = (Add(*xs) for xs in [included, reverted, excluded])
return cls(a) + re(b) + c
def as_real_imag(self, deep=True, **hints):
"""
Return the imaginary part with a zero real part.
"""
return (self, S.Zero)
def _eval_derivative(self, x):
if x.is_extended_real or self.args[0].is_extended_real:
return im(Derivative(self.args[0], x, evaluate=True))
if x.is_imaginary or self.args[0].is_imaginary:
return -I \
* re(Derivative(self.args[0], x, evaluate=True))
def _eval_rewrite_as_re(self, arg, **kwargs):
return -I*(self.args[0] - re(self.args[0]))
def _eval_is_algebraic(self):
return self.args[0].is_algebraic
def _eval_is_zero(self):
return self.args[0].is_extended_real
def _eval_is_finite(self):
if self.args[0].is_finite:
return True
def _eval_is_complex(self):
if self.args[0].is_finite:
return True
###############################################################################
############### SIGN, ABSOLUTE VALUE, ARGUMENT and CONJUGATION ################
###############################################################################
class sign(Function):
"""
Returns the complex sign of an expression:
Explanation
===========
If the expression is real the sign will be:
* $1$ if expression is positive
* $0$ if expression is equal to zero
* $-1$ if expression is negative
If the expression is imaginary the sign will be:
* $I$ if im(expression) is positive
* $-I$ if im(expression) is negative
Otherwise an unevaluated expression will be returned. When evaluated, the
result (in general) will be ``cos(arg(expr)) + I*sin(arg(expr))``.
Examples
========
>>> from sympy import sign, I
>>> sign(-1)
-1
>>> sign(0)
0
>>> sign(-3*I)
-I
>>> sign(1 + I)
sign(1 + I)
>>> _.evalf()
0.707106781186548 + 0.707106781186548*I
Parameters
==========
arg : Expr
Real or imaginary expression.
Returns
=======
expr : Expr
Complex sign of expression.
See Also
========
Abs, conjugate
"""
is_complex = True
_singularities = True
def doit(self, **hints):
s = super().doit()
if s == self and self.args[0].is_zero is False:
return self.args[0] / Abs(self.args[0])
return s
@classmethod
def eval(cls, arg):
# handle what we can
if arg.is_Mul:
c, args = arg.as_coeff_mul()
unk = []
s = sign(c)
for a in args:
if a.is_extended_negative:
s = -s
elif a.is_extended_positive:
pass
else:
if a.is_imaginary:
ai = im(a)
if ai.is_comparable: # i.e. a = I*real
s *= I
if ai.is_extended_negative:
# can't use sign(ai) here since ai might not be
# a Number
s = -s
else:
unk.append(a)
else:
unk.append(a)
if c is S.One and len(unk) == len(args):
return None
return s * cls(arg._new_rawargs(*unk))
if arg is S.NaN:
return S.NaN
if arg.is_zero: # it may be an Expr that is zero
return S.Zero
if arg.is_extended_positive:
return S.One
if arg.is_extended_negative:
return S.NegativeOne
if arg.is_Function:
if isinstance(arg, sign):
return arg
if arg.is_imaginary:
if arg.is_Pow and arg.exp is S.Half:
# we catch this because non-trivial sqrt args are not expanded
# e.g. sqrt(1-sqrt(2)) --x--> to I*sqrt(sqrt(2) - 1)
return I
arg2 = -I * arg
if arg2.is_extended_positive:
return I
if arg2.is_extended_negative:
return -I
def _eval_Abs(self):
if fuzzy_not(self.args[0].is_zero):
return S.One
def _eval_conjugate(self):
return sign(conjugate(self.args[0]))
def _eval_derivative(self, x):
if self.args[0].is_extended_real:
from sympy.functions.special.delta_functions import DiracDelta
return 2 * Derivative(self.args[0], x, evaluate=True) \
* DiracDelta(self.args[0])
elif self.args[0].is_imaginary:
from sympy.functions.special.delta_functions import DiracDelta
return 2 * Derivative(self.args[0], x, evaluate=True) \
* DiracDelta(-I * self.args[0])
def _eval_is_nonnegative(self):
if self.args[0].is_nonnegative:
return True
def _eval_is_nonpositive(self):
if self.args[0].is_nonpositive:
return True
def _eval_is_imaginary(self):
return self.args[0].is_imaginary
def _eval_is_integer(self):
return self.args[0].is_extended_real
def _eval_is_zero(self):
return self.args[0].is_zero
def _eval_power(self, other):
if (
fuzzy_not(self.args[0].is_zero) and
other.is_integer and
other.is_even
):
return S.One
def _eval_nseries(self, x, n, logx, cdir=0):
arg0 = self.args[0]
x0 = arg0.subs(x, 0)
if x0 != 0:
return self.func(x0)
if cdir != 0:
cdir = arg0.dir(x, cdir)
return -S.One if re(cdir) < 0 else S.One
def _eval_rewrite_as_Piecewise(self, arg, **kwargs):
if arg.is_extended_real:
return Piecewise((1, arg > 0), (-1, arg < 0), (0, True))
def _eval_rewrite_as_Heaviside(self, arg, **kwargs):
from sympy.functions.special.delta_functions import Heaviside
if arg.is_extended_real:
return Heaviside(arg) * 2 - 1
def _eval_rewrite_as_Abs(self, arg, **kwargs):
return Piecewise((0, Eq(arg, 0)), (arg / Abs(arg), True))
def _eval_simplify(self, **kwargs):
return self.func(factor_terms(self.args[0])) # XXX include doit?
class Abs(Function):
"""
Return the absolute value of the argument.
Explanation
===========
This is an extension of the built-in function ``abs()`` to accept symbolic
values. If you pass a SymPy expression to the built-in ``abs()``, it will
pass it automatically to ``Abs()``.
Examples
========
>>> from sympy import Abs, Symbol, S, I
>>> Abs(-1)
1
>>> x = Symbol('x', real=True)
>>> Abs(-x)
Abs(x)
>>> Abs(x**2)
x**2
>>> abs(-x) # The Python built-in
Abs(x)
>>> Abs(3*x + 2*I)
sqrt(9*x**2 + 4)
>>> Abs(8*I)
8
Note that the Python built-in will return either an Expr or int depending on
the argument::
>>> type(abs(-1))
<... 'int'>
>>> type(abs(S.NegativeOne))
<class 'sympy.core.numbers.One'>
Abs will always return a SymPy object.
Parameters
==========
arg : Expr
Real or complex expression.
Returns
=======
expr : Expr
Absolute value returned can be an expression or integer depending on
input arg.
See Also
========
sign, conjugate
"""
args: tTuple[Expr]
is_extended_real = True
is_extended_negative = False
is_extended_nonnegative = True
unbranched = True
_singularities = True # non-holomorphic
def fdiff(self, argindex=1):
"""
Get the first derivative of the argument to Abs().
"""
if argindex == 1:
return sign(self.args[0])
else:
raise ArgumentIndexError(self, argindex)
@classmethod
def eval(cls, arg):
from sympy.simplify.simplify import signsimp
if hasattr(arg, '_eval_Abs'):
obj = arg._eval_Abs()
if obj is not None:
return obj
if not isinstance(arg, Expr):
raise TypeError("Bad argument type for Abs(): %s" % type(arg))
# handle what we can
arg = signsimp(arg, evaluate=False)
n, d = arg.as_numer_denom()
if d.free_symbols and not n.free_symbols:
return cls(n)/cls(d)
if arg.is_Mul:
known = []
unk = []
for t in arg.args:
if t.is_Pow and t.exp.is_integer and t.exp.is_negative:
bnew = cls(t.base)
if isinstance(bnew, cls):
unk.append(t)
else:
known.append(Pow(bnew, t.exp))
else:
tnew = cls(t)
if isinstance(tnew, cls):
unk.append(t)
else:
known.append(tnew)
known = Mul(*known)
unk = cls(Mul(*unk), evaluate=False) if unk else S.One
return known*unk
if arg is S.NaN:
return S.NaN
if arg is S.ComplexInfinity:
return oo
from sympy.functions.elementary.exponential import exp, log
if arg.is_Pow:
base, exponent = arg.as_base_exp()
if base.is_extended_real:
if exponent.is_integer:
if exponent.is_even:
return arg
if base is S.NegativeOne:
return S.One
return Abs(base)**exponent
if base.is_extended_nonnegative:
return base**re(exponent)
if base.is_extended_negative:
return (-base)**re(exponent)*exp(-pi*im(exponent))
return
elif not base.has(Symbol): # complex base
# express base**exponent as exp(exponent*log(base))
a, b = log(base).as_real_imag()
z = a + I*b
return exp(re(exponent*z))
if isinstance(arg, exp):
return exp(re(arg.args[0]))
if isinstance(arg, AppliedUndef):
if arg.is_positive:
return arg
elif arg.is_negative:
return -arg
return
if arg.is_Add and arg.has(oo, S.NegativeInfinity):
if any(a.is_infinite for a in arg.as_real_imag()):
return oo
if arg.is_zero:
return S.Zero
if arg.is_extended_nonnegative:
return arg
if arg.is_extended_nonpositive:
return -arg
if arg.is_imaginary:
arg2 = -I * arg
if arg2.is_extended_nonnegative:
return arg2
if arg.is_extended_real:
return
# reject result if all new conjugates are just wrappers around
# an expression that was already in the arg
conj = signsimp(arg.conjugate(), evaluate=False)
new_conj = conj.atoms(conjugate) - arg.atoms(conjugate)
if new_conj and all(arg.has(i.args[0]) for i in new_conj):
return
if arg != conj and arg != -conj:
ignore = arg.atoms(Abs)
abs_free_arg = arg.xreplace({i: Dummy(real=True) for i in ignore})
unk = [a for a in abs_free_arg.free_symbols if a.is_extended_real is None]
if not unk or not all(conj.has(conjugate(u)) for u in unk):
return sqrt(expand_mul(arg*conj))
def _eval_is_real(self):
if self.args[0].is_finite:
return True
def _eval_is_integer(self):
if self.args[0].is_extended_real:
return self.args[0].is_integer
def _eval_is_extended_nonzero(self):
return fuzzy_not(self._args[0].is_zero)
def _eval_is_zero(self):
return self._args[0].is_zero
def _eval_is_extended_positive(self):
return fuzzy_not(self._args[0].is_zero)
def _eval_is_rational(self):
if self.args[0].is_extended_real:
return self.args[0].is_rational
def _eval_is_even(self):
if self.args[0].is_extended_real:
return self.args[0].is_even
def _eval_is_odd(self):
if self.args[0].is_extended_real:
return self.args[0].is_odd
def _eval_is_algebraic(self):
return self.args[0].is_algebraic
def _eval_power(self, exponent):
if self.args[0].is_extended_real and exponent.is_integer:
if exponent.is_even:
return self.args[0]**exponent
elif exponent is not S.NegativeOne and exponent.is_Integer:
return self.args[0]**(exponent - 1)*self
return
def _eval_nseries(self, x, n, logx, cdir=0):
from sympy.functions.elementary.exponential import log
direction = self.args[0].leadterm(x)[0]
if direction.has(log(x)):
direction = direction.subs(log(x), logx)
s = self.args[0]._eval_nseries(x, n=n, logx=logx)
return (sign(direction)*s).expand()
def _eval_derivative(self, x):
if self.args[0].is_extended_real or self.args[0].is_imaginary:
return Derivative(self.args[0], x, evaluate=True) \
* sign(conjugate(self.args[0]))
rv = (re(self.args[0]) * Derivative(re(self.args[0]), x,
evaluate=True) + im(self.args[0]) * Derivative(im(self.args[0]),
x, evaluate=True)) / Abs(self.args[0])
return rv.rewrite(sign)
def _eval_rewrite_as_Heaviside(self, arg, **kwargs):
# Note this only holds for real arg (since Heaviside is not defined
# for complex arguments).
from sympy.functions.special.delta_functions import Heaviside
if arg.is_extended_real:
return arg*(Heaviside(arg) - Heaviside(-arg))
def _eval_rewrite_as_Piecewise(self, arg, **kwargs):
if arg.is_extended_real:
return Piecewise((arg, arg >= 0), (-arg, True))
elif arg.is_imaginary:
return Piecewise((I*arg, I*arg >= 0), (-I*arg, True))
def _eval_rewrite_as_sign(self, arg, **kwargs):
return arg/sign(arg)
def _eval_rewrite_as_conjugate(self, arg, **kwargs):
return sqrt(arg*conjugate(arg))
class arg(Function):
r"""
Returns the argument (in radians) of a complex number. The argument is
evaluated in consistent convention with ``atan2`` where the branch-cut is
taken along the negative real axis and ``arg(z)`` is in the interval
$(-\pi,\pi]$. For a positive number, the argument is always 0; the
argument of a negative number is $\pi$; and the argument of 0
is undefined and returns ``nan``. So the ``arg`` function will never nest
greater than 3 levels since at the 4th application, the result must be
nan; for a real number, nan is returned on the 3rd application.
Examples
========
>>> from sympy import arg, I, sqrt, Dummy
>>> from sympy.abc import x
>>> arg(2.0)
0
>>> arg(I)
pi/2
>>> arg(sqrt(2) + I*sqrt(2))
pi/4
>>> arg(sqrt(3)/2 + I/2)
pi/6
>>> arg(4 + 3*I)
atan(3/4)
>>> arg(0.8 + 0.6*I)
0.643501108793284
>>> arg(arg(arg(arg(x))))
nan
>>> real = Dummy(real=True)
>>> arg(arg(arg(real)))
nan
Parameters
==========
arg : Expr
Real or complex expression.
Returns
=======
value : Expr
Returns arc tangent of arg measured in radians.
"""
is_extended_real = True
is_real = True
is_finite = True
_singularities = True # non-holomorphic
@classmethod
def eval(cls, arg):
a = arg
for i in range(3):
if isinstance(a, cls):
a = a.args[0]
else:
if i == 2 and a.is_extended_real:
return S.NaN
break
else:
return S.NaN
from sympy.functions.elementary.exponential import exp, exp_polar
if isinstance(arg, exp_polar):
return periodic_argument(arg, oo)
elif isinstance(arg, exp):
i_ = im(arg.args[0])
if i_.is_comparable:
i_ %= 2*S.Pi
if i_ > S.Pi:
i_ -= 2*S.Pi
return i_
if not arg.is_Atom:
c, arg_ = factor_terms(arg).as_coeff_Mul()
if arg_.is_Mul:
arg_ = Mul(*[a if (sign(a) not in (-1, 1)) else
sign(a) for a in arg_.args])
arg_ = sign(c)*arg_
else:
arg_ = arg
if any(i.is_extended_positive is None for i in arg_.atoms(AppliedUndef)):
return
from sympy.functions.elementary.trigonometric import atan2
x, y = arg_.as_real_imag()
rv = atan2(y, x)
if rv.is_number:
return rv
if arg_ != arg:
return cls(arg_, evaluate=False)
def _eval_derivative(self, t):
x, y = self.args[0].as_real_imag()
return (x * Derivative(y, t, evaluate=True) - y *
Derivative(x, t, evaluate=True)) / (x**2 + y**2)
def _eval_rewrite_as_atan2(self, arg, **kwargs):
from sympy.functions.elementary.trigonometric import atan2
x, y = self.args[0].as_real_imag()
return atan2(y, x)
class conjugate(Function):
"""
Returns the *complex conjugate* [1]_ of an argument.
In mathematics, the complex conjugate of a complex number
is given by changing the sign of the imaginary part.
Thus, the conjugate of the complex number
:math:`a + ib` (where $a$ and $b$ are real numbers) is :math:`a - ib`
Examples
========
>>> from sympy import conjugate, I
>>> conjugate(2)
2
>>> conjugate(I)
-I
>>> conjugate(3 + 2*I)
3 - 2*I
>>> conjugate(5 - I)
5 + I
Parameters
==========
arg : Expr
Real or complex expression.
Returns
=======
arg : Expr
Complex conjugate of arg as real, imaginary or mixed expression.
See Also
========
sign, Abs
References
==========
.. [1] https://en.wikipedia.org/wiki/Complex_conjugation
"""
_singularities = True # non-holomorphic
@classmethod
def eval(cls, arg):
obj = arg._eval_conjugate()
if obj is not None:
return obj
def inverse(self):
return conjugate
def _eval_Abs(self):
return Abs(self.args[0], evaluate=True)
def _eval_adjoint(self):
return transpose(self.args[0])
def _eval_conjugate(self):
return self.args[0]
def _eval_derivative(self, x):
if x.is_real:
return conjugate(Derivative(self.args[0], x, evaluate=True))
elif x.is_imaginary:
return -conjugate(Derivative(self.args[0], x, evaluate=True))
def _eval_transpose(self):
return adjoint(self.args[0])
def _eval_is_algebraic(self):
return self.args[0].is_algebraic
class transpose(Function):
"""
Linear map transposition.
Examples
========
>>> from sympy import transpose, Matrix, MatrixSymbol
>>> A = MatrixSymbol('A', 25, 9)
>>> transpose(A)
A.T
>>> B = MatrixSymbol('B', 9, 22)
>>> transpose(B)
B.T
>>> transpose(A*B)
B.T*A.T
>>> M = Matrix([[4, 5], [2, 1], [90, 12]])
>>> M
Matrix([
[ 4, 5],
[ 2, 1],
[90, 12]])
>>> transpose(M)
Matrix([
[4, 2, 90],
[5, 1, 12]])
Parameters
==========
arg : Matrix
Matrix or matrix expression to take the transpose of.
Returns
=======
value : Matrix
Transpose of arg.
"""
@classmethod
def eval(cls, arg):
obj = arg._eval_transpose()
if obj is not None:
return obj
def _eval_adjoint(self):
return conjugate(self.args[0])
def _eval_conjugate(self):
return adjoint(self.args[0])
def _eval_transpose(self):
return self.args[0]
class adjoint(Function):
"""
Conjugate transpose or Hermite conjugation.
Examples
========
>>> from sympy import adjoint, MatrixSymbol
>>> A = MatrixSymbol('A', 10, 5)
>>> adjoint(A)
Adjoint(A)
Parameters
==========
arg : Matrix
Matrix or matrix expression to take the adjoint of.
Returns
=======
value : Matrix
Represents the conjugate transpose or Hermite
conjugation of arg.
"""
@classmethod
def eval(cls, arg):
obj = arg._eval_adjoint()
if obj is not None:
return obj
obj = arg._eval_transpose()
if obj is not None:
return conjugate(obj)
def _eval_adjoint(self):
return self.args[0]
def _eval_conjugate(self):
return transpose(self.args[0])
def _eval_transpose(self):
return conjugate(self.args[0])
def _latex(self, printer, exp=None, *args):
arg = printer._print(self.args[0])
tex = r'%s^{\dagger}' % arg
if exp:
tex = r'\left(%s\right)^{%s}' % (tex, exp)
return tex
def _pretty(self, printer, *args):
from sympy.printing.pretty.stringpict import prettyForm
pform = printer._print(self.args[0], *args)
if printer._use_unicode:
pform = pform**prettyForm('\N{DAGGER}')
else:
pform = pform**prettyForm('+')
return pform
###############################################################################
############### HANDLING OF POLAR NUMBERS #####################################
###############################################################################
class polar_lift(Function):
"""
Lift argument to the Riemann surface of the logarithm, using the
standard branch.
Examples
========
>>> from sympy import Symbol, polar_lift, I
>>> p = Symbol('p', polar=True)
>>> x = Symbol('x')
>>> polar_lift(4)
4*exp_polar(0)
>>> polar_lift(-4)
4*exp_polar(I*pi)
>>> polar_lift(-I)
exp_polar(-I*pi/2)
>>> polar_lift(I + 2)
polar_lift(2 + I)
>>> polar_lift(4*x)
4*polar_lift(x)
>>> polar_lift(4*p)
4*p
Parameters
==========
arg : Expr
Real or complex expression.
See Also
========
sympy.functions.elementary.exponential.exp_polar
periodic_argument
"""
is_polar = True
is_comparable = False # Cannot be evalf'd.
@classmethod
def eval(cls, arg):
from sympy.functions.elementary.complexes import arg as argument
if arg.is_number:
ar = argument(arg)
# In general we want to affirm that something is known,
# e.g. `not ar.has(argument) and not ar.has(atan)`
# but for now we will just be more restrictive and
# see that it has evaluated to one of the known values.
if ar in (0, pi/2, -pi/2, pi):
from sympy.functions.elementary.exponential import exp_polar
return exp_polar(I*ar)*abs(arg)
if arg.is_Mul:
args = arg.args
else:
args = [arg]
included = []
excluded = []
positive = []
for arg in args:
if arg.is_polar:
included += [arg]
elif arg.is_positive:
positive += [arg]
else:
excluded += [arg]
if len(excluded) < len(args):
if excluded:
return Mul(*(included + positive))*polar_lift(Mul(*excluded))
elif included:
return Mul(*(included + positive))
else:
from sympy.functions.elementary.exponential import exp_polar
return Mul(*positive)*exp_polar(0)
def _eval_evalf(self, prec):
""" Careful! any evalf of polar numbers is flaky """
return self.args[0]._eval_evalf(prec)
def _eval_Abs(self):
return Abs(self.args[0], evaluate=True)
class periodic_argument(Function):
r"""
Represent the argument on a quotient of the Riemann surface of the
logarithm. That is, given a period $P$, always return a value in
$(-P/2, P/2]$, by using $\exp(PI) = 1$.
Examples
========
>>> from sympy import exp_polar, periodic_argument
>>> from sympy import I, pi
>>> periodic_argument(exp_polar(10*I*pi), 2*pi)
0
>>> periodic_argument(exp_polar(5*I*pi), 4*pi)
pi
>>> from sympy import exp_polar, periodic_argument
>>> from sympy import I, pi
>>> periodic_argument(exp_polar(5*I*pi), 2*pi)
pi
>>> periodic_argument(exp_polar(5*I*pi), 3*pi)
-pi
>>> periodic_argument(exp_polar(5*I*pi), pi)
0
Parameters
==========
ar : Expr
A polar number.
period : Expr
The period $P$.
See Also
========
sympy.functions.elementary.exponential.exp_polar
polar_lift : Lift argument to the Riemann surface of the logarithm
principal_branch
"""
@classmethod
def _getunbranched(cls, ar):
from sympy.functions.elementary.exponential import exp_polar, log
if ar.is_Mul:
args = ar.args
else:
args = [ar]
unbranched = 0
for a in args:
if not a.is_polar:
unbranched += arg(a)
elif isinstance(a, exp_polar):
unbranched += a.exp.as_real_imag()[1]
elif a.is_Pow:
re, im = a.exp.as_real_imag()
unbranched += re*unbranched_argument(
a.base) + im*log(abs(a.base))
elif isinstance(a, polar_lift):
unbranched += arg(a.args[0])
else:
return None
return unbranched
@classmethod
def eval(cls, ar, period):
# Our strategy is to evaluate the argument on the Riemann surface of the
# logarithm, and then reduce.
# NOTE evidently this means it is a rather bad idea to use this with
# period != 2*pi and non-polar numbers.
if not period.is_extended_positive:
return None
if period == oo and isinstance(ar, principal_branch):
return periodic_argument(*ar.args)
if isinstance(ar, polar_lift) and period >= 2*pi:
return periodic_argument(ar.args[0], period)
if ar.is_Mul:
newargs = [x for x in ar.args if not x.is_positive]
if len(newargs) != len(ar.args):
return periodic_argument(Mul(*newargs), period)
unbranched = cls._getunbranched(ar)
if unbranched is None:
return None
from sympy.functions.elementary.trigonometric import atan, atan2
if unbranched.has(periodic_argument, atan2, atan):
return None
if period == oo:
return unbranched
if period != oo:
from sympy.functions.elementary.integers import ceiling
n = ceiling(unbranched/period - S.Half)*period
if not n.has(ceiling):
return unbranched - n
def _eval_evalf(self, prec):
z, period = self.args
if period == oo:
unbranched = periodic_argument._getunbranched(z)
if unbranched is None:
return self
return unbranched._eval_evalf(prec)
ub = periodic_argument(z, oo)._eval_evalf(prec)
from sympy.functions.elementary.integers import ceiling
return (ub - ceiling(ub/period - S.Half)*period)._eval_evalf(prec)
def unbranched_argument(arg):
'''
Returns periodic argument of arg with period as infinity.
Examples
========
>>> from sympy import exp_polar, unbranched_argument
>>> from sympy import I, pi
>>> unbranched_argument(exp_polar(15*I*pi))
15*pi
>>> unbranched_argument(exp_polar(7*I*pi))
7*pi
See also
========
periodic_argument
'''
return periodic_argument(arg, oo)
class principal_branch(Function):
"""
Represent a polar number reduced to its principal branch on a quotient
of the Riemann surface of the logarithm.
Explanation
===========
This is a function of two arguments. The first argument is a polar
number `z`, and the second one a positive real number or infinity, `p`.
The result is ``z mod exp_polar(I*p)``.
Examples
========
>>> from sympy import exp_polar, principal_branch, oo, I, pi
>>> from sympy.abc import z
>>> principal_branch(z, oo)
z
>>> principal_branch(exp_polar(2*pi*I)*3, 2*pi)
3*exp_polar(0)
>>> principal_branch(exp_polar(2*pi*I)*3*z, 2*pi)
3*principal_branch(z, 2*pi)
Parameters
==========
x : Expr
A polar number.
period : Expr
Positive real number or infinity.
See Also
========
sympy.functions.elementary.exponential.exp_polar
polar_lift : Lift argument to the Riemann surface of the logarithm
periodic_argument
"""
is_polar = True
is_comparable = False # cannot always be evalf'd
@classmethod
def eval(self, x, period):
from sympy.functions.elementary.exponential import exp_polar
if isinstance(x, polar_lift):
return principal_branch(x.args[0], period)
if period == oo:
return x
ub = periodic_argument(x, oo)
barg = periodic_argument(x, period)
if ub != barg and not ub.has(periodic_argument) \
and not barg.has(periodic_argument):
pl = polar_lift(x)
def mr(expr):
if not isinstance(expr, Symbol):
return polar_lift(expr)
return expr
pl = pl.replace(polar_lift, mr)
# Recompute unbranched argument
ub = periodic_argument(pl, oo)
if not pl.has(polar_lift):
if ub != barg:
res = exp_polar(I*(barg - ub))*pl
else:
res = pl
if not res.is_polar and not res.has(exp_polar):
res *= exp_polar(0)
return res
if not x.free_symbols:
c, m = x, ()
else:
c, m = x.as_coeff_mul(*x.free_symbols)
others = []
for y in m:
if y.is_positive:
c *= y
else:
others += [y]
m = tuple(others)
arg = periodic_argument(c, period)
if arg.has(periodic_argument):
return None
if arg.is_number and (unbranched_argument(c) != arg or
(arg == 0 and m != () and c != 1)):
if arg == 0:
return abs(c)*principal_branch(Mul(*m), period)
return principal_branch(exp_polar(I*arg)*Mul(*m), period)*abs(c)
if arg.is_number and ((abs(arg) < period/2) == True or arg == period/2) \
and m == ():
return exp_polar(arg*I)*abs(c)
def _eval_evalf(self, prec):
z, period = self.args
p = periodic_argument(z, period)._eval_evalf(prec)
if abs(p) > pi or p == -pi:
return self # Cannot evalf for this argument.
from sympy.functions.elementary.exponential import exp
return (abs(z)*exp(I*p))._eval_evalf(prec)
def _polarify(eq, lift, pause=False):
from sympy.integrals.integrals import Integral
if eq.is_polar:
return eq
if eq.is_number and not pause:
return polar_lift(eq)
if isinstance(eq, Symbol) and not pause and lift:
return polar_lift(eq)
elif eq.is_Atom:
return eq
elif eq.is_Add:
r = eq.func(*[_polarify(arg, lift, pause=True) for arg in eq.args])
if lift:
return polar_lift(r)
return r
elif eq.is_Pow and eq.base == S.Exp1:
return eq.func(S.Exp1, _polarify(eq.exp, lift, pause=False))
elif eq.is_Function:
return eq.func(*[_polarify(arg, lift, pause=False) for arg in eq.args])
elif isinstance(eq, Integral):
# Don't lift the integration variable
func = _polarify(eq.function, lift, pause=pause)
limits = []
for limit in eq.args[1:]:
var = _polarify(limit[0], lift=False, pause=pause)
rest = _polarify(limit[1:], lift=lift, pause=pause)
limits.append((var,) + rest)
return Integral(*((func,) + tuple(limits)))
else:
return eq.func(*[_polarify(arg, lift, pause=pause)
if isinstance(arg, Expr) else arg for arg in eq.args])
def polarify(eq, subs=True, lift=False):
"""
Turn all numbers in eq into their polar equivalents (under the standard
choice of argument).
Note that no attempt is made to guess a formal convention of adding
polar numbers, expressions like $1 + x$ will generally not be altered.
Note also that this function does not promote ``exp(x)`` to ``exp_polar(x)``.
If ``subs`` is ``True``, all symbols which are not already polar will be
substituted for polar dummies; in this case the function behaves much
like :func:`~.posify`.
If ``lift`` is ``True``, both addition statements and non-polar symbols are
changed to their ``polar_lift()``ed versions.
Note that ``lift=True`` implies ``subs=False``.
Examples
========
>>> from sympy import polarify, sin, I
>>> from sympy.abc import x, y
>>> expr = (-x)**y
>>> expr.expand()
(-x)**y
>>> polarify(expr)
((_x*exp_polar(I*pi))**_y, {_x: x, _y: y})
>>> polarify(expr)[0].expand()
_x**_y*exp_polar(_y*I*pi)
>>> polarify(x, lift=True)
polar_lift(x)
>>> polarify(x*(1+y), lift=True)
polar_lift(x)*polar_lift(y + 1)
Adds are treated carefully:
>>> polarify(1 + sin((1 + I)*x))
(sin(_x*polar_lift(1 + I)) + 1, {_x: x})
"""
if lift:
subs = False
eq = _polarify(sympify(eq), lift)
if not subs:
return eq
reps = {s: Dummy(s.name, polar=True) for s in eq.free_symbols}
eq = eq.subs(reps)
return eq, {r: s for s, r in reps.items()}
def _unpolarify(eq, exponents_only, pause=False):
if not isinstance(eq, Basic) or eq.is_Atom:
return eq
if not pause:
from sympy.functions.elementary.exponential import exp, exp_polar
if isinstance(eq, exp_polar):
return exp(_unpolarify(eq.exp, exponents_only))
if isinstance(eq, principal_branch) and eq.args[1] == 2*pi:
return _unpolarify(eq.args[0], exponents_only)
if (
eq.is_Add or eq.is_Mul or eq.is_Boolean or
eq.is_Relational and (
eq.rel_op in ('==', '!=') and 0 in eq.args or
eq.rel_op not in ('==', '!='))
):
return eq.func(*[_unpolarify(x, exponents_only) for x in eq.args])
if isinstance(eq, polar_lift):
return _unpolarify(eq.args[0], exponents_only)
if eq.is_Pow:
expo = _unpolarify(eq.exp, exponents_only)
base = _unpolarify(eq.base, exponents_only,
not (expo.is_integer and not pause))
return base**expo
if eq.is_Function and getattr(eq.func, 'unbranched', False):
return eq.func(*[_unpolarify(x, exponents_only, exponents_only)
for x in eq.args])
return eq.func(*[_unpolarify(x, exponents_only, True) for x in eq.args])
def unpolarify(eq, subs=None, exponents_only=False):
"""
If `p` denotes the projection from the Riemann surface of the logarithm to
the complex line, return a simplified version `eq'` of `eq` such that
`p(eq') = p(eq)`.
Also apply the substitution subs in the end. (This is a convenience, since
``unpolarify``, in a certain sense, undoes :func:`polarify`.)
Examples
========
>>> from sympy import unpolarify, polar_lift, sin, I
>>> unpolarify(polar_lift(I + 2))
2 + I
>>> unpolarify(sin(polar_lift(I + 7)))
sin(7 + I)
"""
if isinstance(eq, bool):
return eq
eq = sympify(eq)
if subs is not None:
return unpolarify(eq.subs(subs))
changed = True
pause = False
if exponents_only:
pause = True
while changed:
changed = False
res = _unpolarify(eq, exponents_only, pause)
if res != eq:
changed = True
eq = res
if isinstance(res, bool):
return res
# Finally, replacing Exp(0) by 1 is always correct.
# So is polar_lift(0) -> 0.
from sympy.functions.elementary.exponential import exp_polar
return res.subs({exp_polar(0): 1, polar_lift(0): 0})
PK ]ZZZ.�B� � ) sympy/functions/elementary/exponential.pyfrom itertools import product
from typing import Tuple as tTuple
from sympy.core.add import Add
from sympy.core.cache import cacheit
from sympy.core.expr import Expr
from sympy.core.function import (Function, ArgumentIndexError, expand_log,
expand_mul, FunctionClass, PoleError, expand_multinomial, expand_complex)
from sympy.core.logic import fuzzy_and, fuzzy_not, fuzzy_or
from sympy.core.mul import Mul
from sympy.core.numbers import Integer, Rational, pi, I
from sympy.core.parameters import global_parameters
from sympy.core.power import Pow
from sympy.core.singleton import S
from sympy.core.symbol import Wild, Dummy
from sympy.core.sympify import sympify
from sympy.functions.combinatorial.factorials import factorial
from sympy.functions.elementary.complexes import arg, unpolarify, im, re, Abs
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.ntheory import multiplicity, perfect_power
from sympy.ntheory.factor_ import factorint
# NOTE IMPORTANT
# The series expansion code in this file is an important part of the gruntz
# algorithm for determining limits. _eval_nseries has to return a generalized
# power series with coefficients in C(log(x), log).
# In more detail, the result of _eval_nseries(self, x, n) must be
# c_0*x**e_0 + ... (finitely many terms)
# where e_i are numbers (not necessarily integers) and c_i involve only
# numbers, the function log, and log(x). [This also means it must not contain
# log(x(1+p)), this *has* to be expanded to log(x)+log(1+p) if x.is_positive and
# p.is_positive.]
class ExpBase(Function):
unbranched = True
_singularities = (S.ComplexInfinity,)
@property
def kind(self):
return self.exp.kind
def inverse(self, argindex=1):
"""
Returns the inverse function of ``exp(x)``.
"""
return log
def as_numer_denom(self):
"""
Returns this with a positive exponent as a 2-tuple (a fraction).
Examples
========
>>> from sympy import exp
>>> from sympy.abc import x
>>> exp(-x).as_numer_denom()
(1, exp(x))
>>> exp(x).as_numer_denom()
(exp(x), 1)
"""
# this should be the same as Pow.as_numer_denom wrt
# exponent handling
if not self.is_commutative:
return self, S.One
exp = self.exp
neg_exp = exp.is_negative
if not neg_exp and not (-exp).is_negative:
neg_exp = exp.could_extract_minus_sign()
if neg_exp:
return S.One, self.func(-exp)
return self, S.One
@property
def exp(self):
"""
Returns the exponent of the function.
"""
return self.args[0]
def as_base_exp(self):
"""
Returns the 2-tuple (base, exponent).
"""
return self.func(1), Mul(*self.args)
def _eval_adjoint(self):
return self.func(self.exp.adjoint())
def _eval_conjugate(self):
return self.func(self.exp.conjugate())
def _eval_transpose(self):
return self.func(self.exp.transpose())
def _eval_is_finite(self):
arg = self.exp
if arg.is_infinite:
if arg.is_extended_negative:
return True
if arg.is_extended_positive:
return False
if arg.is_finite:
return True
def _eval_is_rational(self):
s = self.func(*self.args)
if s.func == self.func:
z = s.exp.is_zero
if z:
return True
elif s.exp.is_rational and fuzzy_not(z):
return False
else:
return s.is_rational
def _eval_is_zero(self):
return self.exp is S.NegativeInfinity
def _eval_power(self, other):
"""exp(arg)**e -> exp(arg*e) if assumptions allow it.
"""
b, e = self.as_base_exp()
return Pow._eval_power(Pow(b, e, evaluate=False), other)
def _eval_expand_power_exp(self, **hints):
from sympy.concrete.products import Product
from sympy.concrete.summations import Sum
arg = self.args[0]
if arg.is_Add and arg.is_commutative:
return Mul.fromiter(self.func(x) for x in arg.args)
elif isinstance(arg, Sum) and arg.is_commutative:
return Product(self.func(arg.function), *arg.limits)
return self.func(arg)
class exp_polar(ExpBase):
r"""
Represent a *polar number* (see g-function Sphinx documentation).
Explanation
===========
``exp_polar`` represents the function
`Exp: \mathbb{C} \rightarrow \mathcal{S}`, sending the complex number
`z = a + bi` to the polar number `r = exp(a), \theta = b`. It is one of
the main functions to construct polar numbers.
Examples
========
>>> from sympy import exp_polar, pi, I, exp
The main difference is that polar numbers do not "wrap around" at `2 \pi`:
>>> exp(2*pi*I)
1
>>> exp_polar(2*pi*I)
exp_polar(2*I*pi)
apart from that they behave mostly like classical complex numbers:
>>> exp_polar(2)*exp_polar(3)
exp_polar(5)
See Also
========
sympy.simplify.powsimp.powsimp
polar_lift
periodic_argument
principal_branch
"""
is_polar = True
is_comparable = False # cannot be evalf'd
def _eval_Abs(self): # Abs is never a polar number
return exp(re(self.args[0]))
def _eval_evalf(self, prec):
""" Careful! any evalf of polar numbers is flaky """
i = im(self.args[0])
try:
bad = (i <= -pi or i > pi)
except TypeError:
bad = True
if bad:
return self # cannot evalf for this argument
res = exp(self.args[0])._eval_evalf(prec)
if i > 0 and im(res) < 0:
# i ~ pi, but exp(I*i) evaluated to argument slightly bigger than pi
return re(res)
return res
def _eval_power(self, other):
return self.func(self.args[0]*other)
def _eval_is_extended_real(self):
if self.args[0].is_extended_real:
return True
def as_base_exp(self):
# XXX exp_polar(0) is special!
if self.args[0] == 0:
return self, S.One
return ExpBase.as_base_exp(self)
class ExpMeta(FunctionClass):
def __instancecheck__(cls, instance):
if exp in instance.__class__.__mro__:
return True
return isinstance(instance, Pow) and instance.base is S.Exp1
class exp(ExpBase, metaclass=ExpMeta):
"""
The exponential function, :math:`e^x`.
Examples
========
>>> from sympy import exp, I, pi
>>> from sympy.abc import x
>>> exp(x)
exp(x)
>>> exp(x).diff(x)
exp(x)
>>> exp(I*pi)
-1
Parameters
==========
arg : Expr
See Also
========
log
"""
def fdiff(self, argindex=1):
"""
Returns the first derivative of this function.
"""
if argindex == 1:
return self
else:
raise ArgumentIndexError(self, argindex)
def _eval_refine(self, assumptions):
from sympy.assumptions import ask, Q
arg = self.args[0]
if arg.is_Mul:
Ioo = I*S.Infinity
if arg in [Ioo, -Ioo]:
return S.NaN
coeff = arg.as_coefficient(pi*I)
if coeff:
if ask(Q.integer(2*coeff)):
if ask(Q.even(coeff)):
return S.One
elif ask(Q.odd(coeff)):
return S.NegativeOne
elif ask(Q.even(coeff + S.Half)):
return -I
elif ask(Q.odd(coeff + S.Half)):
return I
@classmethod
def eval(cls, arg):
from sympy.calculus import AccumBounds
from sympy.matrices.matrixbase import MatrixBase
from sympy.sets.setexpr import SetExpr
from sympy.simplify.simplify import logcombine
if isinstance(arg, MatrixBase):
return arg.exp()
elif global_parameters.exp_is_pow:
return Pow(S.Exp1, arg)
elif arg.is_Number:
if arg is S.NaN:
return S.NaN
elif arg.is_zero:
return S.One
elif arg is S.One:
return S.Exp1
elif arg is S.Infinity:
return S.Infinity
elif arg is S.NegativeInfinity:
return S.Zero
elif arg is S.ComplexInfinity:
return S.NaN
elif isinstance(arg, log):
return arg.args[0]
elif isinstance(arg, AccumBounds):
return AccumBounds(exp(arg.min), exp(arg.max))
elif isinstance(arg, SetExpr):
return arg._eval_func(cls)
elif arg.is_Mul:
coeff = arg.as_coefficient(pi*I)
if coeff:
if (2*coeff).is_integer:
if coeff.is_even:
return S.One
elif coeff.is_odd:
return S.NegativeOne
elif (coeff + S.Half).is_even:
return -I
elif (coeff + S.Half).is_odd:
return I
elif coeff.is_Rational:
ncoeff = coeff % 2 # restrict to [0, 2pi)
if ncoeff > 1: # restrict to (-pi, pi]
ncoeff -= 2
if ncoeff != coeff:
return cls(ncoeff*pi*I)
# Warning: code in risch.py will be very sensitive to changes
# in this (see DifferentialExtension).
# look for a single log factor
coeff, terms = arg.as_coeff_Mul()
# but it can't be multiplied by oo
if coeff in [S.NegativeInfinity, S.Infinity]:
if terms.is_number:
if coeff is S.NegativeInfinity:
terms = -terms
if re(terms).is_zero and terms is not S.Zero:
return S.NaN
if re(terms).is_positive and im(terms) is not S.Zero:
return S.ComplexInfinity
if re(terms).is_negative:
return S.Zero
return None
coeffs, log_term = [coeff], None
for term in Mul.make_args(terms):
term_ = logcombine(term)
if isinstance(term_, log):
if log_term is None:
log_term = term_.args[0]
else:
return None
elif term.is_comparable:
coeffs.append(term)
else:
return None
return log_term**Mul(*coeffs) if log_term else None
elif arg.is_Add:
out = []
add = []
argchanged = False
for a in arg.args:
if a is S.One:
add.append(a)
continue
newa = cls(a)
if isinstance(newa, cls):
if newa.args[0] != a:
add.append(newa.args[0])
argchanged = True
else:
add.append(a)
else:
out.append(newa)
if out or argchanged:
return Mul(*out)*cls(Add(*add), evaluate=False)
if arg.is_zero:
return S.One
@property
def base(self):
"""
Returns the base of the exponential function.
"""
return S.Exp1
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
"""
Calculates the next term in the Taylor series expansion.
"""
if n < 0:
return S.Zero
if n == 0:
return S.One
x = sympify(x)
if previous_terms:
p = previous_terms[-1]
if p is not None:
return p * x / n
return x**n/factorial(n)
def as_real_imag(self, deep=True, **hints):
"""
Returns this function as a 2-tuple representing a complex number.
Examples
========
>>> from sympy import exp, I
>>> from sympy.abc import x
>>> exp(x).as_real_imag()
(exp(re(x))*cos(im(x)), exp(re(x))*sin(im(x)))
>>> exp(1).as_real_imag()
(E, 0)
>>> exp(I).as_real_imag()
(cos(1), sin(1))
>>> exp(1+I).as_real_imag()
(E*cos(1), E*sin(1))
See Also
========
sympy.functions.elementary.complexes.re
sympy.functions.elementary.complexes.im
"""
from sympy.functions.elementary.trigonometric import cos, sin
re, im = self.args[0].as_real_imag()
if deep:
re = re.expand(deep, **hints)
im = im.expand(deep, **hints)
cos, sin = cos(im), sin(im)
return (exp(re)*cos, exp(re)*sin)
def _eval_subs(self, old, new):
# keep processing of power-like args centralized in Pow
if old.is_Pow: # handle (exp(3*log(x))).subs(x**2, z) -> z**(3/2)
old = exp(old.exp*log(old.base))
elif old is S.Exp1 and new.is_Function:
old = exp
if isinstance(old, exp) or old is S.Exp1:
f = lambda a: Pow(*a.as_base_exp(), evaluate=False) if (
a.is_Pow or isinstance(a, exp)) else a
return Pow._eval_subs(f(self), f(old), new)
if old is exp and not new.is_Function:
return new**self.exp._subs(old, new)
return Function._eval_subs(self, old, new)
def _eval_is_extended_real(self):
if self.args[0].is_extended_real:
return True
elif self.args[0].is_imaginary:
arg2 = -S(2) * I * self.args[0] / pi
return arg2.is_even
def _eval_is_complex(self):
def complex_extended_negative(arg):
yield arg.is_complex
yield arg.is_extended_negative
return fuzzy_or(complex_extended_negative(self.args[0]))
def _eval_is_algebraic(self):
if (self.exp / pi / I).is_rational:
return True
if fuzzy_not(self.exp.is_zero):
if self.exp.is_algebraic:
return False
elif (self.exp / pi).is_rational:
return False
def _eval_is_extended_positive(self):
if self.exp.is_extended_real:
return self.args[0] is not S.NegativeInfinity
elif self.exp.is_imaginary:
arg2 = -I * self.args[0] / pi
return arg2.is_even
def _eval_nseries(self, x, n, logx, cdir=0):
# NOTE Please see the comment at the beginning of this file, labelled
# IMPORTANT.
from sympy.functions.elementary.complexes import sign
from sympy.functions.elementary.integers import ceiling
from sympy.series.limits import limit
from sympy.series.order import Order
from sympy.simplify.powsimp import powsimp
arg = self.exp
arg_series = arg._eval_nseries(x, n=n, logx=logx)
if arg_series.is_Order:
return 1 + arg_series
arg0 = limit(arg_series.removeO(), x, 0)
if arg0 is S.NegativeInfinity:
return Order(x**n, x)
if arg0 is S.Infinity:
return self
if arg0.is_infinite:
raise PoleError("Cannot expand %s around 0" % (self))
# checking for indecisiveness/ sign terms in arg0
if any(isinstance(arg, sign) for arg in arg0.args):
return self
t = Dummy("t")
nterms = n
try:
cf = Order(arg.as_leading_term(x, logx=logx), x).getn()
except (NotImplementedError, PoleError):
cf = 0
if cf and cf > 0:
nterms = ceiling(n/cf)
exp_series = exp(t)._taylor(t, nterms)
r = exp(arg0)*exp_series.subs(t, arg_series - arg0)
rep = {logx: log(x)} if logx is not None else {}
if r.subs(rep) == self:
return r
if cf and cf > 1:
r += Order((arg_series - arg0)**n, x)/x**((cf-1)*n)
else:
r += Order((arg_series - arg0)**n, x)
r = r.expand()
r = powsimp(r, deep=True, combine='exp')
# powsimp may introduce unexpanded (-1)**Rational; see PR #17201
simplerat = lambda x: x.is_Rational and x.q in [3, 4, 6]
w = Wild('w', properties=[simplerat])
r = r.replace(S.NegativeOne**w, expand_complex(S.NegativeOne**w))
return r
def _taylor(self, x, n):
l = []
g = None
for i in range(n):
g = self.taylor_term(i, self.args[0], g)
g = g.nseries(x, n=n)
l.append(g.removeO())
return Add(*l)
def _eval_as_leading_term(self, x, logx=None, cdir=0):
from sympy.calculus.util import AccumBounds
arg = self.args[0].cancel().as_leading_term(x, logx=logx)
arg0 = arg.subs(x, 0)
if arg is S.NaN:
return S.NaN
if isinstance(arg0, AccumBounds):
# This check addresses a corner case involving AccumBounds.
# if isinstance(arg, AccumBounds) is True, then arg0 can either be 0,
# AccumBounds(-oo, 0) or AccumBounds(-oo, oo).
# Check out function: test_issue_18473() in test_exponential.py and
# test_limits.py for more information.
if re(cdir) < S.Zero:
return exp(-arg0)
return exp(arg0)
if arg0 is S.NaN:
arg0 = arg.limit(x, 0)
if arg0.is_infinite is False:
return exp(arg0)
raise PoleError("Cannot expand %s around 0" % (self))
def _eval_rewrite_as_sin(self, arg, **kwargs):
from sympy.functions.elementary.trigonometric import sin
return sin(I*arg + pi/2) - I*sin(I*arg)
def _eval_rewrite_as_cos(self, arg, **kwargs):
from sympy.functions.elementary.trigonometric import cos
return cos(I*arg) + I*cos(I*arg + pi/2)
def _eval_rewrite_as_tanh(self, arg, **kwargs):
from sympy.functions.elementary.hyperbolic import tanh
return (1 + tanh(arg/2))/(1 - tanh(arg/2))
def _eval_rewrite_as_sqrt(self, arg, **kwargs):
from sympy.functions.elementary.trigonometric import sin, cos
if arg.is_Mul:
coeff = arg.coeff(pi*I)
if coeff and coeff.is_number:
cosine, sine = cos(pi*coeff), sin(pi*coeff)
if not isinstance(cosine, cos) and not isinstance (sine, sin):
return cosine + I*sine
def _eval_rewrite_as_Pow(self, arg, **kwargs):
if arg.is_Mul:
logs = [a for a in arg.args if isinstance(a, log) and len(a.args) == 1]
if logs:
return Pow(logs[0].args[0], arg.coeff(logs[0]))
def match_real_imag(expr):
r"""
Try to match expr with $a + Ib$ for real $a$ and $b$.
``match_real_imag`` returns a tuple containing the real and imaginary
parts of expr or ``(None, None)`` if direct matching is not possible. Contrary
to :func:`~.re`, :func:`~.im``, and ``as_real_imag()``, this helper will not force things
by returning expressions themselves containing ``re()`` or ``im()`` and it
does not expand its argument either.
"""
r_, i_ = expr.as_independent(I, as_Add=True)
if i_ == 0 and r_.is_real:
return (r_, i_)
i_ = i_.as_coefficient(I)
if i_ and i_.is_real and r_.is_real:
return (r_, i_)
else:
return (None, None) # simpler to check for than None
class log(Function):
r"""
The natural logarithm function `\ln(x)` or `\log(x)`.
Explanation
===========
Logarithms are taken with the natural base, `e`. To get
a logarithm of a different base ``b``, use ``log(x, b)``,
which is essentially short-hand for ``log(x)/log(b)``.
``log`` represents the principal branch of the natural
logarithm. As such it has a branch cut along the negative
real axis and returns values having a complex argument in
`(-\pi, \pi]`.
Examples
========
>>> from sympy import log, sqrt, S, I
>>> log(8, 2)
3
>>> log(S(8)/3, 2)
-log(3)/log(2) + 3
>>> log(-1 + I*sqrt(3))
log(2) + 2*I*pi/3
See Also
========
exp
"""
args: tTuple[Expr]
_singularities = (S.Zero, S.ComplexInfinity)
def fdiff(self, argindex=1):
"""
Returns the first derivative of the function.
"""
if argindex == 1:
return 1/self.args[0]
else:
raise ArgumentIndexError(self, argindex)
def inverse(self, argindex=1):
r"""
Returns `e^x`, the inverse function of `\log(x)`.
"""
return exp
@classmethod
def eval(cls, arg, base=None):
from sympy.calculus import AccumBounds
from sympy.sets.setexpr import SetExpr
arg = sympify(arg)
if base is not None:
base = sympify(base)
if base == 1:
if arg == 1:
return S.NaN
else:
return S.ComplexInfinity
try:
# handle extraction of powers of the base now
# or else expand_log in Mul would have to handle this
n = multiplicity(base, arg)
if n:
return n + log(arg / base**n) / log(base)
else:
return log(arg)/log(base)
except ValueError:
pass
if base is not S.Exp1:
return cls(arg)/cls(base)
else:
return cls(arg)
if arg.is_Number:
if arg.is_zero:
return S.ComplexInfinity
elif arg is S.One:
return S.Zero
elif arg is S.Infinity:
return S.Infinity
elif arg is S.NegativeInfinity:
return S.Infinity
elif arg is S.NaN:
return S.NaN
elif arg.is_Rational and arg.p == 1:
return -cls(arg.q)
if arg.is_Pow and arg.base is S.Exp1 and arg.exp.is_extended_real:
return arg.exp
if isinstance(arg, exp) and arg.exp.is_extended_real:
return arg.exp
elif isinstance(arg, exp) and arg.exp.is_number:
r_, i_ = match_real_imag(arg.exp)
if i_ and i_.is_comparable:
i_ %= 2*pi
if i_ > pi:
i_ -= 2*pi
return r_ + expand_mul(i_ * I, deep=False)
elif isinstance(arg, exp_polar):
return unpolarify(arg.exp)
elif isinstance(arg, AccumBounds):
if arg.min.is_positive:
return AccumBounds(log(arg.min), log(arg.max))
elif arg.min.is_zero:
return AccumBounds(S.NegativeInfinity, log(arg.max))
else:
return S.NaN
elif isinstance(arg, SetExpr):
return arg._eval_func(cls)
if arg.is_number:
if arg.is_negative:
return pi * I + cls(-arg)
elif arg is S.ComplexInfinity:
return S.ComplexInfinity
elif arg is S.Exp1:
return S.One
if arg.is_zero:
return S.ComplexInfinity
# don't autoexpand Pow or Mul (see the issue 3351):
if not arg.is_Add:
coeff = arg.as_coefficient(I)
if coeff is not None:
if coeff is S.Infinity:
return S.Infinity
elif coeff is S.NegativeInfinity:
return S.Infinity
elif coeff.is_Rational:
if coeff.is_nonnegative:
return pi * I * S.Half + cls(coeff)
else:
return -pi * I * S.Half + cls(-coeff)
if arg.is_number and arg.is_algebraic:
# Match arg = coeff*(r_ + i_*I) with coeff>0, r_ and i_ real.
coeff, arg_ = arg.as_independent(I, as_Add=False)
if coeff.is_negative:
coeff *= -1
arg_ *= -1
arg_ = expand_mul(arg_, deep=False)
r_, i_ = arg_.as_independent(I, as_Add=True)
i_ = i_.as_coefficient(I)
if coeff.is_real and i_ and i_.is_real and r_.is_real:
if r_.is_zero:
if i_.is_positive:
return pi * I * S.Half + cls(coeff * i_)
elif i_.is_negative:
return -pi * I * S.Half + cls(coeff * -i_)
else:
from sympy.simplify import ratsimp
# Check for arguments involving rational multiples of pi
t = (i_/r_).cancel()
t1 = (-t).cancel()
atan_table = _log_atan_table()
if t in atan_table:
modulus = ratsimp(coeff * Abs(arg_))
if r_.is_positive:
return cls(modulus) + I * atan_table[t]
else:
return cls(modulus) + I * (atan_table[t] - pi)
elif t1 in atan_table:
modulus = ratsimp(coeff * Abs(arg_))
if r_.is_positive:
return cls(modulus) + I * (-atan_table[t1])
else:
return cls(modulus) + I * (pi - atan_table[t1])
def as_base_exp(self):
"""
Returns this function in the form (base, exponent).
"""
return self, S.One
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms): # of log(1+x)
r"""
Returns the next term in the Taylor series expansion of `\log(1+x)`.
"""
from sympy.simplify.powsimp import powsimp
if n < 0:
return S.Zero
x = sympify(x)
if n == 0:
return x
if previous_terms:
p = previous_terms[-1]
if p is not None:
return powsimp((-n) * p * x / (n + 1), deep=True, combine='exp')
return (1 - 2*(n % 2)) * x**(n + 1)/(n + 1)
def _eval_expand_log(self, deep=True, **hints):
from sympy.concrete import Sum, Product
force = hints.get('force', False)
factor = hints.get('factor', False)
if (len(self.args) == 2):
return expand_log(self.func(*self.args), deep=deep, force=force)
arg = self.args[0]
if arg.is_Integer:
# remove perfect powers
p = perfect_power(arg)
logarg = None
coeff = 1
if p is not False:
arg, coeff = p
logarg = self.func(arg)
# expand as product of its prime factors if factor=True
if factor:
p = factorint(arg)
if arg not in p.keys():
logarg = sum(n*log(val) for val, n in p.items())
if logarg is not None:
return coeff*logarg
elif arg.is_Rational:
return log(arg.p) - log(arg.q)
elif arg.is_Mul:
expr = []
nonpos = []
for x in arg.args:
if force or x.is_positive or x.is_polar:
a = self.func(x)
if isinstance(a, log):
expr.append(self.func(x)._eval_expand_log(**hints))
else:
expr.append(a)
elif x.is_negative:
a = self.func(-x)
expr.append(a)
nonpos.append(S.NegativeOne)
else:
nonpos.append(x)
return Add(*expr) + log(Mul(*nonpos))
elif arg.is_Pow or isinstance(arg, exp):
if force or (arg.exp.is_extended_real and (arg.base.is_positive or ((arg.exp+1)
.is_positive and (arg.exp-1).is_nonpositive))) or arg.base.is_polar:
b = arg.base
e = arg.exp
a = self.func(b)
if isinstance(a, log):
return unpolarify(e) * a._eval_expand_log(**hints)
else:
return unpolarify(e) * a
elif isinstance(arg, Product):
if force or arg.function.is_positive:
return Sum(log(arg.function), *arg.limits)
return self.func(arg)
def _eval_simplify(self, **kwargs):
from sympy.simplify.simplify import expand_log, simplify, inversecombine
if len(self.args) == 2: # it's unevaluated
return simplify(self.func(*self.args), **kwargs)
expr = self.func(simplify(self.args[0], **kwargs))
if kwargs['inverse']:
expr = inversecombine(expr)
expr = expand_log(expr, deep=True)
return min([expr, self], key=kwargs['measure'])
def as_real_imag(self, deep=True, **hints):
"""
Returns this function as a complex coordinate.
Examples
========
>>> from sympy import I, log
>>> from sympy.abc import x
>>> log(x).as_real_imag()
(log(Abs(x)), arg(x))
>>> log(I).as_real_imag()
(0, pi/2)
>>> log(1 + I).as_real_imag()
(log(sqrt(2)), pi/4)
>>> log(I*x).as_real_imag()
(log(Abs(x)), arg(I*x))
"""
sarg = self.args[0]
if deep:
sarg = self.args[0].expand(deep, **hints)
sarg_abs = Abs(sarg)
if sarg_abs == sarg:
return self, S.Zero
sarg_arg = arg(sarg)
if hints.get('log', False): # Expand the log
hints['complex'] = False
return (log(sarg_abs).expand(deep, **hints), sarg_arg)
else:
return log(sarg_abs), sarg_arg
def _eval_is_rational(self):
s = self.func(*self.args)
if s.func == self.func:
if (self.args[0] - 1).is_zero:
return True
if s.args[0].is_rational and fuzzy_not((self.args[0] - 1).is_zero):
return False
else:
return s.is_rational
def _eval_is_algebraic(self):
s = self.func(*self.args)
if s.func == self.func:
if (self.args[0] - 1).is_zero:
return True
elif fuzzy_not((self.args[0] - 1).is_zero):
if self.args[0].is_algebraic:
return False
else:
return s.is_algebraic
def _eval_is_extended_real(self):
return self.args[0].is_extended_positive
def _eval_is_complex(self):
z = self.args[0]
return fuzzy_and([z.is_complex, fuzzy_not(z.is_zero)])
def _eval_is_finite(self):
arg = self.args[0]
if arg.is_zero:
return False
return arg.is_finite
def _eval_is_extended_positive(self):
return (self.args[0] - 1).is_extended_positive
def _eval_is_zero(self):
return (self.args[0] - 1).is_zero
def _eval_is_extended_nonnegative(self):
return (self.args[0] - 1).is_extended_nonnegative
def _eval_nseries(self, x, n, logx, cdir=0):
# NOTE Please see the comment at the beginning of this file, labelled
# IMPORTANT.
from sympy.series.order import Order
from sympy.simplify.simplify import logcombine
from sympy.core.symbol import Dummy
if self.args[0] == x:
return log(x) if logx is None else logx
arg = self.args[0]
t = Dummy('t', positive=True)
if cdir == 0:
cdir = 1
z = arg.subs(x, cdir*t)
k, l = Wild("k"), Wild("l")
r = z.match(k*t**l)
if r is not None:
k, l = r[k], r[l]
if l != 0 and not l.has(t) and not k.has(t):
r = l*log(x) if logx is None else l*logx
r += log(k) - l*log(cdir) # XXX true regardless of assumptions?
return r
def coeff_exp(term, x):
coeff, exp = S.One, S.Zero
for factor in Mul.make_args(term):
if factor.has(x):
base, exp = factor.as_base_exp()
if base != x:
try:
return term.leadterm(x)
except ValueError:
return term, S.Zero
else:
coeff *= factor
return coeff, exp
# TODO new and probably slow
try:
a, b = z.leadterm(t, logx=logx, cdir=1)
except (ValueError, NotImplementedError, PoleError):
s = z._eval_nseries(t, n=n, logx=logx, cdir=1)
while s.is_Order:
n += 1
s = z._eval_nseries(t, n=n, logx=logx, cdir=1)
try:
a, b = s.removeO().leadterm(t, cdir=1)
except ValueError:
a, b = s.removeO().as_leading_term(t, cdir=1), S.Zero
p = (z/(a*t**b) - 1)._eval_nseries(t, n=n, logx=logx, cdir=1)
if p.has(exp):
p = logcombine(p)
if isinstance(p, Order):
n = p.getn()
_, d = coeff_exp(p, t)
logx = log(x) if logx is None else logx
if not d.is_positive:
res = log(a) - b*log(cdir) + b*logx
_res = res
logflags = {"deep": True, "log": True, "mul": False, "power_exp": False,
"power_base": False, "multinomial": False, "basic": False, "force": True,
"factor": False}
expr = self.expand(**logflags)
if (not a.could_extract_minus_sign() and
logx.could_extract_minus_sign()):
_res = _res.subs(-logx, -log(x)).expand(**logflags)
else:
_res = _res.subs(logx, log(x)).expand(**logflags)
if _res == expr:
return res
return res + Order(x**n, x)
def mul(d1, d2):
res = {}
for e1, e2 in product(d1, d2):
ex = e1 + e2
if ex < n:
res[ex] = res.get(ex, S.Zero) + d1[e1]*d2[e2]
return res
pterms = {}
for term in Add.make_args(p.removeO()):
co1, e1 = coeff_exp(term, t)
pterms[e1] = pterms.get(e1, S.Zero) + co1
k = S.One
terms = {}
pk = pterms
while k*d < n:
coeff = -S.NegativeOne**k/k
for ex in pk:
_ = terms.get(ex, S.Zero) + coeff*pk[ex]
terms[ex] = _.nsimplify()
pk = mul(pk, pterms)
k += S.One
res = log(a) - b*log(cdir) + b*logx
for ex in terms:
res += terms[ex]*t**(ex)
if a.is_negative and im(z) != 0:
from sympy.functions.special.delta_functions import Heaviside
for i, term in enumerate(z.lseries(t)):
if not term.is_real or i == 5:
break
if i < 5:
coeff, _ = term.as_coeff_exponent(t)
res += -2*I*pi*Heaviside(-im(coeff), 0)
res = res.subs(t, x/cdir)
return res + Order(x**n, x)
def _eval_as_leading_term(self, x, logx=None, cdir=0):
# NOTE
# Refer https://github.com/sympy/sympy/pull/23592 for more information
# on each of the following steps involved in this method.
arg0 = self.args[0].together()
# STEP 1
t = Dummy('t', positive=True)
if cdir == 0:
cdir = 1
z = arg0.subs(x, cdir*t)
# STEP 2
try:
c, e = z.leadterm(t, logx=logx, cdir=1)
except ValueError:
arg = arg0.as_leading_term(x, logx=logx, cdir=cdir)
return log(arg)
if c.has(t):
c = c.subs(t, x/cdir)
if e != 0:
raise PoleError("Cannot expand %s around 0" % (self))
return log(c)
# STEP 3
if c == S.One and e == S.Zero:
return (arg0 - S.One).as_leading_term(x, logx=logx)
# STEP 4
res = log(c) - e*log(cdir)
logx = log(x) if logx is None else logx
res += e*logx
# STEP 5
if c.is_negative and im(z) != 0:
from sympy.functions.special.delta_functions import Heaviside
for i, term in enumerate(z.lseries(t)):
if not term.is_real or i == 5:
break
if i < 5:
coeff, _ = term.as_coeff_exponent(t)
res += -2*I*pi*Heaviside(-im(coeff), 0)
return res
class LambertW(Function):
r"""
The Lambert W function $W(z)$ is defined as the inverse
function of $w \exp(w)$ [1]_.
Explanation
===========
In other words, the value of $W(z)$ is such that $z = W(z) \exp(W(z))$
for any complex number $z$. The Lambert W function is a multivalued
function with infinitely many branches $W_k(z)$, indexed by
$k \in \mathbb{Z}$. Each branch gives a different solution $w$
of the equation $z = w \exp(w)$.
The Lambert W function has two partially real branches: the
principal branch ($k = 0$) is real for real $z > -1/e$, and the
$k = -1$ branch is real for $-1/e < z < 0$. All branches except
$k = 0$ have a logarithmic singularity at $z = 0$.
Examples
========
>>> from sympy import LambertW
>>> LambertW(1.2)
0.635564016364870
>>> LambertW(1.2, -1).n()
-1.34747534407696 - 4.41624341514535*I
>>> LambertW(-1).is_real
False
References
==========
.. [1] https://en.wikipedia.org/wiki/Lambert_W_function
"""
_singularities = (-Pow(S.Exp1, -1, evaluate=False), S.ComplexInfinity)
@classmethod
def eval(cls, x, k=None):
if k == S.Zero:
return cls(x)
elif k is None:
k = S.Zero
if k.is_zero:
if x.is_zero:
return S.Zero
if x is S.Exp1:
return S.One
if x == -1/S.Exp1:
return S.NegativeOne
if x == -log(2)/2:
return -log(2)
if x == 2*log(2):
return log(2)
if x == -pi/2:
return I*pi/2
if x == exp(1 + S.Exp1):
return S.Exp1
if x is S.Infinity:
return S.Infinity
if fuzzy_not(k.is_zero):
if x.is_zero:
return S.NegativeInfinity
if k is S.NegativeOne:
if x == -pi/2:
return -I*pi/2
elif x == -1/S.Exp1:
return S.NegativeOne
elif x == -2*exp(-2):
return -Integer(2)
def fdiff(self, argindex=1):
"""
Return the first derivative of this function.
"""
x = self.args[0]
if len(self.args) == 1:
if argindex == 1:
return LambertW(x)/(x*(1 + LambertW(x)))
else:
k = self.args[1]
if argindex == 1:
return LambertW(x, k)/(x*(1 + LambertW(x, k)))
raise ArgumentIndexError(self, argindex)
def _eval_is_extended_real(self):
x = self.args[0]
if len(self.args) == 1:
k = S.Zero
else:
k = self.args[1]
if k.is_zero:
if (x + 1/S.Exp1).is_positive:
return True
elif (x + 1/S.Exp1).is_nonpositive:
return False
elif (k + 1).is_zero:
if x.is_negative and (x + 1/S.Exp1).is_positive:
return True
elif x.is_nonpositive or (x + 1/S.Exp1).is_nonnegative:
return False
elif fuzzy_not(k.is_zero) and fuzzy_not((k + 1).is_zero):
if x.is_extended_real:
return False
def _eval_is_finite(self):
return self.args[0].is_finite
def _eval_is_algebraic(self):
s = self.func(*self.args)
if s.func == self.func:
if fuzzy_not(self.args[0].is_zero) and self.args[0].is_algebraic:
return False
else:
return s.is_algebraic
def _eval_as_leading_term(self, x, logx=None, cdir=0):
if len(self.args) == 1:
arg = self.args[0]
arg0 = arg.subs(x, 0).cancel()
if not arg0.is_zero:
return self.func(arg0)
return arg.as_leading_term(x)
def _eval_nseries(self, x, n, logx, cdir=0):
if len(self.args) == 1:
from sympy.functions.elementary.integers import ceiling
from sympy.series.order import Order
arg = self.args[0].nseries(x, n=n, logx=logx)
lt = arg.as_leading_term(x, logx=logx)
lte = 1
if lt.is_Pow:
lte = lt.exp
if ceiling(n/lte) >= 1:
s = Add(*[(-S.One)**(k - 1)*Integer(k)**(k - 2)/
factorial(k - 1)*arg**k for k in range(1, ceiling(n/lte))])
s = expand_multinomial(s)
else:
s = S.Zero
return s + Order(x**n, x)
return super()._eval_nseries(x, n, logx)
def _eval_is_zero(self):
x = self.args[0]
if len(self.args) == 1:
return x.is_zero
else:
return fuzzy_and([x.is_zero, self.args[1].is_zero])
@cacheit
def _log_atan_table():
return {
# first quadrant only
sqrt(3): pi / 3,
1: pi / 4,
sqrt(5 - 2 * sqrt(5)): pi / 5,
sqrt(2) * sqrt(5 - sqrt(5)) / (1 + sqrt(5)): pi / 5,
sqrt(5 + 2 * sqrt(5)): pi * Rational(2, 5),
sqrt(2) * sqrt(sqrt(5) + 5) / (-1 + sqrt(5)): pi * Rational(2, 5),
sqrt(3) / 3: pi / 6,
sqrt(2) - 1: pi / 8,
sqrt(2 - sqrt(2)) / sqrt(sqrt(2) + 2): pi / 8,
sqrt(2) + 1: pi * Rational(3, 8),
sqrt(sqrt(2) + 2) / sqrt(2 - sqrt(2)): pi * Rational(3, 8),
sqrt(1 - 2 * sqrt(5) / 5): pi / 10,
(-sqrt(2) + sqrt(10)) / (2 * sqrt(sqrt(5) + 5)): pi / 10,
sqrt(1 + 2 * sqrt(5) / 5): pi * Rational(3, 10),
(sqrt(2) + sqrt(10)) / (2 * sqrt(5 - sqrt(5))): pi * Rational(3, 10),
2 - sqrt(3): pi / 12,
(-1 + sqrt(3)) / (1 + sqrt(3)): pi / 12,
2 + sqrt(3): pi * Rational(5, 12),
(1 + sqrt(3)) / (-1 + sqrt(3)): pi * Rational(5, 12)
}
PK ]ZZZ�G\zS S ( sympy/functions/elementary/hyperbolic.pyfrom sympy.core import S, sympify, cacheit
from sympy.core.add import Add
from sympy.core.function import Function, ArgumentIndexError
from sympy.core.logic import fuzzy_or, fuzzy_and, fuzzy_not, FuzzyBool
from sympy.core.numbers import I, pi, Rational
from sympy.core.symbol import Dummy
from sympy.functions.combinatorial.factorials import (binomial, factorial,
RisingFactorial)
from sympy.functions.combinatorial.numbers import bernoulli, euler, nC
from sympy.functions.elementary.complexes import Abs, im, re
from sympy.functions.elementary.exponential import exp, log, match_real_imag
from sympy.functions.elementary.integers import floor
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.elementary.trigonometric import (
acos, acot, asin, atan, cos, cot, csc, sec, sin, tan,
_imaginary_unit_as_coefficient)
from sympy.polys.specialpolys import symmetric_poly
def _rewrite_hyperbolics_as_exp(expr):
return expr.xreplace({h: h.rewrite(exp)
for h in expr.atoms(HyperbolicFunction)})
@cacheit
def _acosh_table():
return {
I: log(I*(1 + sqrt(2))),
-I: log(-I*(1 + sqrt(2))),
S.Half: pi/3,
Rational(-1, 2): pi*Rational(2, 3),
sqrt(2)/2: pi/4,
-sqrt(2)/2: pi*Rational(3, 4),
1/sqrt(2): pi/4,
-1/sqrt(2): pi*Rational(3, 4),
sqrt(3)/2: pi/6,
-sqrt(3)/2: pi*Rational(5, 6),
(sqrt(3) - 1)/sqrt(2**3): pi*Rational(5, 12),
-(sqrt(3) - 1)/sqrt(2**3): pi*Rational(7, 12),
sqrt(2 + sqrt(2))/2: pi/8,
-sqrt(2 + sqrt(2))/2: pi*Rational(7, 8),
sqrt(2 - sqrt(2))/2: pi*Rational(3, 8),
-sqrt(2 - sqrt(2))/2: pi*Rational(5, 8),
(1 + sqrt(3))/(2*sqrt(2)): pi/12,
-(1 + sqrt(3))/(2*sqrt(2)): pi*Rational(11, 12),
(sqrt(5) + 1)/4: pi/5,
-(sqrt(5) + 1)/4: pi*Rational(4, 5)
}
@cacheit
def _acsch_table():
return {
I: -pi / 2,
I*(sqrt(2) + sqrt(6)): -pi / 12,
I*(1 + sqrt(5)): -pi / 10,
I*2 / sqrt(2 - sqrt(2)): -pi / 8,
I*2: -pi / 6,
I*sqrt(2 + 2/sqrt(5)): -pi / 5,
I*sqrt(2): -pi / 4,
I*(sqrt(5)-1): -3*pi / 10,
I*2 / sqrt(3): -pi / 3,
I*2 / sqrt(2 + sqrt(2)): -3*pi / 8,
I*sqrt(2 - 2/sqrt(5)): -2*pi / 5,
I*(sqrt(6) - sqrt(2)): -5*pi / 12,
S(2): -I*log((1+sqrt(5))/2),
}
@cacheit
def _asech_table():
return {
I: - (pi*I / 2) + log(1 + sqrt(2)),
-I: (pi*I / 2) + log(1 + sqrt(2)),
(sqrt(6) - sqrt(2)): pi / 12,
(sqrt(2) - sqrt(6)): 11*pi / 12,
sqrt(2 - 2/sqrt(5)): pi / 10,
-sqrt(2 - 2/sqrt(5)): 9*pi / 10,
2 / sqrt(2 + sqrt(2)): pi / 8,
-2 / sqrt(2 + sqrt(2)): 7*pi / 8,
2 / sqrt(3): pi / 6,
-2 / sqrt(3): 5*pi / 6,
(sqrt(5) - 1): pi / 5,
(1 - sqrt(5)): 4*pi / 5,
sqrt(2): pi / 4,
-sqrt(2): 3*pi / 4,
sqrt(2 + 2/sqrt(5)): 3*pi / 10,
-sqrt(2 + 2/sqrt(5)): 7*pi / 10,
S(2): pi / 3,
-S(2): 2*pi / 3,
sqrt(2*(2 + sqrt(2))): 3*pi / 8,
-sqrt(2*(2 + sqrt(2))): 5*pi / 8,
(1 + sqrt(5)): 2*pi / 5,
(-1 - sqrt(5)): 3*pi / 5,
(sqrt(6) + sqrt(2)): 5*pi / 12,
(-sqrt(6) - sqrt(2)): 7*pi / 12,
I*S.Infinity: -pi*I / 2,
I*S.NegativeInfinity: pi*I / 2,
}
###############################################################################
########################### HYPERBOLIC FUNCTIONS ##############################
###############################################################################
class HyperbolicFunction(Function):
"""
Base class for hyperbolic functions.
See Also
========
sinh, cosh, tanh, coth
"""
unbranched = True
def _peeloff_ipi(arg):
r"""
Split ARG into two parts, a "rest" and a multiple of $I\pi$.
This assumes ARG to be an ``Add``.
The multiple of $I\pi$ returned in the second position is always a ``Rational``.
Examples
========
>>> from sympy.functions.elementary.hyperbolic import _peeloff_ipi as peel
>>> from sympy import pi, I
>>> from sympy.abc import x, y
>>> peel(x + I*pi/2)
(x, 1/2)
>>> peel(x + I*2*pi/3 + I*pi*y)
(x + I*pi*y + I*pi/6, 1/2)
"""
ipi = pi*I
for a in Add.make_args(arg):
if a == ipi:
K = S.One
break
elif a.is_Mul:
K, p = a.as_two_terms()
if p == ipi and K.is_Rational:
break
else:
return arg, S.Zero
m1 = (K % S.Half)
m2 = K - m1
return arg - m2*ipi, m2
class sinh(HyperbolicFunction):
r"""
``sinh(x)`` is the hyperbolic sine of ``x``.
The hyperbolic sine function is $\frac{e^x - e^{-x}}{2}$.
Examples
========
>>> from sympy import sinh
>>> from sympy.abc import x
>>> sinh(x)
sinh(x)
See Also
========
cosh, tanh, asinh
"""
def fdiff(self, argindex=1):
"""
Returns the first derivative of this function.
"""
if argindex == 1:
return cosh(self.args[0])
else:
raise ArgumentIndexError(self, argindex)
def inverse(self, argindex=1):
"""
Returns the inverse of this function.
"""
return asinh
@classmethod
def eval(cls, arg):
if arg.is_Number:
if arg is S.NaN:
return S.NaN
elif arg is S.Infinity:
return S.Infinity
elif arg is S.NegativeInfinity:
return S.NegativeInfinity
elif arg.is_zero:
return S.Zero
elif arg.is_negative:
return -cls(-arg)
else:
if arg is S.ComplexInfinity:
return S.NaN
i_coeff = _imaginary_unit_as_coefficient(arg)
if i_coeff is not None:
return I * sin(i_coeff)
else:
if arg.could_extract_minus_sign():
return -cls(-arg)
if arg.is_Add:
x, m = _peeloff_ipi(arg)
if m:
m = m*pi*I
return sinh(m)*cosh(x) + cosh(m)*sinh(x)
if arg.is_zero:
return S.Zero
if arg.func == asinh:
return arg.args[0]
if arg.func == acosh:
x = arg.args[0]
return sqrt(x - 1) * sqrt(x + 1)
if arg.func == atanh:
x = arg.args[0]
return x/sqrt(1 - x**2)
if arg.func == acoth:
x = arg.args[0]
return 1/(sqrt(x - 1) * sqrt(x + 1))
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
"""
Returns the next term in the Taylor series expansion.
"""
if n < 0 or n % 2 == 0:
return S.Zero
else:
x = sympify(x)
if len(previous_terms) > 2:
p = previous_terms[-2]
return p * x**2 / (n*(n - 1))
else:
return x**(n) / factorial(n)
def _eval_conjugate(self):
return self.func(self.args[0].conjugate())
def as_real_imag(self, deep=True, **hints):
"""
Returns this function as a complex coordinate.
"""
if self.args[0].is_extended_real:
if deep:
hints['complex'] = False
return (self.expand(deep, **hints), S.Zero)
else:
return (self, S.Zero)
if deep:
re, im = self.args[0].expand(deep, **hints).as_real_imag()
else:
re, im = self.args[0].as_real_imag()
return (sinh(re)*cos(im), cosh(re)*sin(im))
def _eval_expand_complex(self, deep=True, **hints):
re_part, im_part = self.as_real_imag(deep=deep, **hints)
return re_part + im_part*I
def _eval_expand_trig(self, deep=True, **hints):
if deep:
arg = self.args[0].expand(deep, **hints)
else:
arg = self.args[0]
x = None
if arg.is_Add: # TODO, implement more if deep stuff here
x, y = arg.as_two_terms()
else:
coeff, terms = arg.as_coeff_Mul(rational=True)
if coeff is not S.One and coeff.is_Integer and terms is not S.One:
x = terms
y = (coeff - 1)*x
if x is not None:
return (sinh(x)*cosh(y) + sinh(y)*cosh(x)).expand(trig=True)
return sinh(arg)
def _eval_rewrite_as_tractable(self, arg, limitvar=None, **kwargs):
return (exp(arg) - exp(-arg)) / 2
def _eval_rewrite_as_exp(self, arg, **kwargs):
return (exp(arg) - exp(-arg)) / 2
def _eval_rewrite_as_sin(self, arg, **kwargs):
return -I * sin(I * arg)
def _eval_rewrite_as_csc(self, arg, **kwargs):
return -I / csc(I * arg)
def _eval_rewrite_as_cosh(self, arg, **kwargs):
return -I*cosh(arg + pi*I/2)
def _eval_rewrite_as_tanh(self, arg, **kwargs):
tanh_half = tanh(S.Half*arg)
return 2*tanh_half/(1 - tanh_half**2)
def _eval_rewrite_as_coth(self, arg, **kwargs):
coth_half = coth(S.Half*arg)
return 2*coth_half/(coth_half**2 - 1)
def _eval_rewrite_as_csch(self, arg, **kwargs):
return 1 / csch(arg)
def _eval_as_leading_term(self, x, logx=None, cdir=0):
arg = self.args[0].as_leading_term(x, logx=logx, cdir=cdir)
arg0 = arg.subs(x, 0)
if arg0 is S.NaN:
arg0 = arg.limit(x, 0, dir='-' if cdir.is_negative else '+')
if arg0.is_zero:
return arg
elif arg0.is_finite:
return self.func(arg0)
else:
return self
def _eval_is_real(self):
arg = self.args[0]
if arg.is_real:
return True
# if `im` is of the form n*pi
# else, check if it is a number
re, im = arg.as_real_imag()
return (im%pi).is_zero
def _eval_is_extended_real(self):
if self.args[0].is_extended_real:
return True
def _eval_is_positive(self):
if self.args[0].is_extended_real:
return self.args[0].is_positive
def _eval_is_negative(self):
if self.args[0].is_extended_real:
return self.args[0].is_negative
def _eval_is_finite(self):
arg = self.args[0]
return arg.is_finite
def _eval_is_zero(self):
rest, ipi_mult = _peeloff_ipi(self.args[0])
if rest.is_zero:
return ipi_mult.is_integer
class cosh(HyperbolicFunction):
r"""
``cosh(x)`` is the hyperbolic cosine of ``x``.
The hyperbolic cosine function is $\frac{e^x + e^{-x}}{2}$.
Examples
========
>>> from sympy import cosh
>>> from sympy.abc import x
>>> cosh(x)
cosh(x)
See Also
========
sinh, tanh, acosh
"""
def fdiff(self, argindex=1):
if argindex == 1:
return sinh(self.args[0])
else:
raise ArgumentIndexError(self, argindex)
@classmethod
def eval(cls, arg):
from sympy.functions.elementary.trigonometric import cos
if arg.is_Number:
if arg is S.NaN:
return S.NaN
elif arg is S.Infinity:
return S.Infinity
elif arg is S.NegativeInfinity:
return S.Infinity
elif arg.is_zero:
return S.One
elif arg.is_negative:
return cls(-arg)
else:
if arg is S.ComplexInfinity:
return S.NaN
i_coeff = _imaginary_unit_as_coefficient(arg)
if i_coeff is not None:
return cos(i_coeff)
else:
if arg.could_extract_minus_sign():
return cls(-arg)
if arg.is_Add:
x, m = _peeloff_ipi(arg)
if m:
m = m*pi*I
return cosh(m)*cosh(x) + sinh(m)*sinh(x)
if arg.is_zero:
return S.One
if arg.func == asinh:
return sqrt(1 + arg.args[0]**2)
if arg.func == acosh:
return arg.args[0]
if arg.func == atanh:
return 1/sqrt(1 - arg.args[0]**2)
if arg.func == acoth:
x = arg.args[0]
return x/(sqrt(x - 1) * sqrt(x + 1))
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
if n < 0 or n % 2 == 1:
return S.Zero
else:
x = sympify(x)
if len(previous_terms) > 2:
p = previous_terms[-2]
return p * x**2 / (n*(n - 1))
else:
return x**(n)/factorial(n)
def _eval_conjugate(self):
return self.func(self.args[0].conjugate())
def as_real_imag(self, deep=True, **hints):
if self.args[0].is_extended_real:
if deep:
hints['complex'] = False
return (self.expand(deep, **hints), S.Zero)
else:
return (self, S.Zero)
if deep:
re, im = self.args[0].expand(deep, **hints).as_real_imag()
else:
re, im = self.args[0].as_real_imag()
return (cosh(re)*cos(im), sinh(re)*sin(im))
def _eval_expand_complex(self, deep=True, **hints):
re_part, im_part = self.as_real_imag(deep=deep, **hints)
return re_part + im_part*I
def _eval_expand_trig(self, deep=True, **hints):
if deep:
arg = self.args[0].expand(deep, **hints)
else:
arg = self.args[0]
x = None
if arg.is_Add: # TODO, implement more if deep stuff here
x, y = arg.as_two_terms()
else:
coeff, terms = arg.as_coeff_Mul(rational=True)
if coeff is not S.One and coeff.is_Integer and terms is not S.One:
x = terms
y = (coeff - 1)*x
if x is not None:
return (cosh(x)*cosh(y) + sinh(x)*sinh(y)).expand(trig=True)
return cosh(arg)
def _eval_rewrite_as_tractable(self, arg, limitvar=None, **kwargs):
return (exp(arg) + exp(-arg)) / 2
def _eval_rewrite_as_exp(self, arg, **kwargs):
return (exp(arg) + exp(-arg)) / 2
def _eval_rewrite_as_cos(self, arg, **kwargs):
return cos(I * arg, evaluate=False)
def _eval_rewrite_as_sec(self, arg, **kwargs):
return 1 / sec(I * arg, evaluate=False)
def _eval_rewrite_as_sinh(self, arg, **kwargs):
return -I*sinh(arg + pi*I/2, evaluate=False)
def _eval_rewrite_as_tanh(self, arg, **kwargs):
tanh_half = tanh(S.Half*arg)**2
return (1 + tanh_half)/(1 - tanh_half)
def _eval_rewrite_as_coth(self, arg, **kwargs):
coth_half = coth(S.Half*arg)**2
return (coth_half + 1)/(coth_half - 1)
def _eval_rewrite_as_sech(self, arg, **kwargs):
return 1 / sech(arg)
def _eval_as_leading_term(self, x, logx=None, cdir=0):
arg = self.args[0].as_leading_term(x, logx=logx, cdir=cdir)
arg0 = arg.subs(x, 0)
if arg0 is S.NaN:
arg0 = arg.limit(x, 0, dir='-' if cdir.is_negative else '+')
if arg0.is_zero:
return S.One
elif arg0.is_finite:
return self.func(arg0)
else:
return self
def _eval_is_real(self):
arg = self.args[0]
# `cosh(x)` is real for real OR purely imaginary `x`
if arg.is_real or arg.is_imaginary:
return True
# cosh(a+ib) = cos(b)*cosh(a) + i*sin(b)*sinh(a)
# the imaginary part can be an expression like n*pi
# if not, check if the imaginary part is a number
re, im = arg.as_real_imag()
return (im%pi).is_zero
def _eval_is_positive(self):
# cosh(x+I*y) = cos(y)*cosh(x) + I*sin(y)*sinh(x)
# cosh(z) is positive iff it is real and the real part is positive.
# So we need sin(y)*sinh(x) = 0 which gives x=0 or y=n*pi
# Case 1 (y=n*pi): cosh(z) = (-1)**n * cosh(x) -> positive for n even
# Case 2 (x=0): cosh(z) = cos(y) -> positive when cos(y) is positive
z = self.args[0]
x, y = z.as_real_imag()
ymod = y % (2*pi)
yzero = ymod.is_zero
# shortcut if ymod is zero
if yzero:
return True
xzero = x.is_zero
# shortcut x is not zero
if xzero is False:
return yzero
return fuzzy_or([
# Case 1:
yzero,
# Case 2:
fuzzy_and([
xzero,
fuzzy_or([ymod < pi/2, ymod > 3*pi/2])
])
])
def _eval_is_nonnegative(self):
z = self.args[0]
x, y = z.as_real_imag()
ymod = y % (2*pi)
yzero = ymod.is_zero
# shortcut if ymod is zero
if yzero:
return True
xzero = x.is_zero
# shortcut x is not zero
if xzero is False:
return yzero
return fuzzy_or([
# Case 1:
yzero,
# Case 2:
fuzzy_and([
xzero,
fuzzy_or([ymod <= pi/2, ymod >= 3*pi/2])
])
])
def _eval_is_finite(self):
arg = self.args[0]
return arg.is_finite
def _eval_is_zero(self):
rest, ipi_mult = _peeloff_ipi(self.args[0])
if ipi_mult and rest.is_zero:
return (ipi_mult - S.Half).is_integer
class tanh(HyperbolicFunction):
r"""
``tanh(x)`` is the hyperbolic tangent of ``x``.
The hyperbolic tangent function is $\frac{\sinh(x)}{\cosh(x)}$.
Examples
========
>>> from sympy import tanh
>>> from sympy.abc import x
>>> tanh(x)
tanh(x)
See Also
========
sinh, cosh, atanh
"""
def fdiff(self, argindex=1):
if argindex == 1:
return S.One - tanh(self.args[0])**2
else:
raise ArgumentIndexError(self, argindex)
def inverse(self, argindex=1):
"""
Returns the inverse of this function.
"""
return atanh
@classmethod
def eval(cls, arg):
if arg.is_Number:
if arg is S.NaN:
return S.NaN
elif arg is S.Infinity:
return S.One
elif arg is S.NegativeInfinity:
return S.NegativeOne
elif arg.is_zero:
return S.Zero
elif arg.is_negative:
return -cls(-arg)
else:
if arg is S.ComplexInfinity:
return S.NaN
i_coeff = _imaginary_unit_as_coefficient(arg)
if i_coeff is not None:
if i_coeff.could_extract_minus_sign():
return -I * tan(-i_coeff)
return I * tan(i_coeff)
else:
if arg.could_extract_minus_sign():
return -cls(-arg)
if arg.is_Add:
x, m = _peeloff_ipi(arg)
if m:
tanhm = tanh(m*pi*I)
if tanhm is S.ComplexInfinity:
return coth(x)
else: # tanhm == 0
return tanh(x)
if arg.is_zero:
return S.Zero
if arg.func == asinh:
x = arg.args[0]
return x/sqrt(1 + x**2)
if arg.func == acosh:
x = arg.args[0]
return sqrt(x - 1) * sqrt(x + 1) / x
if arg.func == atanh:
return arg.args[0]
if arg.func == acoth:
return 1/arg.args[0]
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
if n < 0 or n % 2 == 0:
return S.Zero
else:
x = sympify(x)
a = 2**(n + 1)
B = bernoulli(n + 1)
F = factorial(n + 1)
return a*(a - 1) * B/F * x**n
def _eval_conjugate(self):
return self.func(self.args[0].conjugate())
def as_real_imag(self, deep=True, **hints):
if self.args[0].is_extended_real:
if deep:
hints['complex'] = False
return (self.expand(deep, **hints), S.Zero)
else:
return (self, S.Zero)
if deep:
re, im = self.args[0].expand(deep, **hints).as_real_imag()
else:
re, im = self.args[0].as_real_imag()
denom = sinh(re)**2 + cos(im)**2
return (sinh(re)*cosh(re)/denom, sin(im)*cos(im)/denom)
def _eval_expand_trig(self, **hints):
arg = self.args[0]
if arg.is_Add:
n = len(arg.args)
TX = [tanh(x, evaluate=False)._eval_expand_trig()
for x in arg.args]
p = [0, 0] # [den, num]
for i in range(n + 1):
p[i % 2] += symmetric_poly(i, TX)
return p[1]/p[0]
elif arg.is_Mul:
coeff, terms = arg.as_coeff_Mul()
if coeff.is_Integer and coeff > 1:
T = tanh(terms)
n = [nC(range(coeff), k)*T**k for k in range(1, coeff + 1, 2)]
d = [nC(range(coeff), k)*T**k for k in range(0, coeff + 1, 2)]
return Add(*n)/Add(*d)
return tanh(arg)
def _eval_rewrite_as_tractable(self, arg, limitvar=None, **kwargs):
neg_exp, pos_exp = exp(-arg), exp(arg)
return (pos_exp - neg_exp)/(pos_exp + neg_exp)
def _eval_rewrite_as_exp(self, arg, **kwargs):
neg_exp, pos_exp = exp(-arg), exp(arg)
return (pos_exp - neg_exp)/(pos_exp + neg_exp)
def _eval_rewrite_as_tan(self, arg, **kwargs):
return -I * tan(I * arg, evaluate=False)
def _eval_rewrite_as_cot(self, arg, **kwargs):
return -I / cot(I * arg, evaluate=False)
def _eval_rewrite_as_sinh(self, arg, **kwargs):
return I*sinh(arg)/sinh(pi*I/2 - arg, evaluate=False)
def _eval_rewrite_as_cosh(self, arg, **kwargs):
return I*cosh(pi*I/2 - arg, evaluate=False)/cosh(arg)
def _eval_rewrite_as_coth(self, arg, **kwargs):
return 1/coth(arg)
def _eval_as_leading_term(self, x, logx=None, cdir=0):
from sympy.series.order import Order
arg = self.args[0].as_leading_term(x)
if x in arg.free_symbols and Order(1, x).contains(arg):
return arg
else:
return self.func(arg)
def _eval_is_real(self):
arg = self.args[0]
if arg.is_real:
return True
re, im = arg.as_real_imag()
# if denom = 0, tanh(arg) = zoo
if re == 0 and im % pi == pi/2:
return None
# check if im is of the form n*pi/2 to make sin(2*im) = 0
# if not, im could be a number, return False in that case
return (im % (pi/2)).is_zero
def _eval_is_extended_real(self):
if self.args[0].is_extended_real:
return True
def _eval_is_positive(self):
if self.args[0].is_extended_real:
return self.args[0].is_positive
def _eval_is_negative(self):
if self.args[0].is_extended_real:
return self.args[0].is_negative
def _eval_is_finite(self):
arg = self.args[0]
re, im = arg.as_real_imag()
denom = cos(im)**2 + sinh(re)**2
if denom == 0:
return False
elif denom.is_number:
return True
if arg.is_extended_real:
return True
def _eval_is_zero(self):
arg = self.args[0]
if arg.is_zero:
return True
class coth(HyperbolicFunction):
r"""
``coth(x)`` is the hyperbolic cotangent of ``x``.
The hyperbolic cotangent function is $\frac{\cosh(x)}{\sinh(x)}$.
Examples
========
>>> from sympy import coth
>>> from sympy.abc import x
>>> coth(x)
coth(x)
See Also
========
sinh, cosh, acoth
"""
def fdiff(self, argindex=1):
if argindex == 1:
return -1/sinh(self.args[0])**2
else:
raise ArgumentIndexError(self, argindex)
def inverse(self, argindex=1):
"""
Returns the inverse of this function.
"""
return acoth
@classmethod
def eval(cls, arg):
if arg.is_Number:
if arg is S.NaN:
return S.NaN
elif arg is S.Infinity:
return S.One
elif arg is S.NegativeInfinity:
return S.NegativeOne
elif arg.is_zero:
return S.ComplexInfinity
elif arg.is_negative:
return -cls(-arg)
else:
if arg is S.ComplexInfinity:
return S.NaN
i_coeff = _imaginary_unit_as_coefficient(arg)
if i_coeff is not None:
if i_coeff.could_extract_minus_sign():
return I * cot(-i_coeff)
return -I * cot(i_coeff)
else:
if arg.could_extract_minus_sign():
return -cls(-arg)
if arg.is_Add:
x, m = _peeloff_ipi(arg)
if m:
cothm = coth(m*pi*I)
if cothm is S.ComplexInfinity:
return coth(x)
else: # cothm == 0
return tanh(x)
if arg.is_zero:
return S.ComplexInfinity
if arg.func == asinh:
x = arg.args[0]
return sqrt(1 + x**2)/x
if arg.func == acosh:
x = arg.args[0]
return x/(sqrt(x - 1) * sqrt(x + 1))
if arg.func == atanh:
return 1/arg.args[0]
if arg.func == acoth:
return arg.args[0]
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
if n == 0:
return 1 / sympify(x)
elif n < 0 or n % 2 == 0:
return S.Zero
else:
x = sympify(x)
B = bernoulli(n + 1)
F = factorial(n + 1)
return 2**(n + 1) * B/F * x**n
def _eval_conjugate(self):
return self.func(self.args[0].conjugate())
def as_real_imag(self, deep=True, **hints):
from sympy.functions.elementary.trigonometric import (cos, sin)
if self.args[0].is_extended_real:
if deep:
hints['complex'] = False
return (self.expand(deep, **hints), S.Zero)
else:
return (self, S.Zero)
if deep:
re, im = self.args[0].expand(deep, **hints).as_real_imag()
else:
re, im = self.args[0].as_real_imag()
denom = sinh(re)**2 + sin(im)**2
return (sinh(re)*cosh(re)/denom, -sin(im)*cos(im)/denom)
def _eval_rewrite_as_tractable(self, arg, limitvar=None, **kwargs):
neg_exp, pos_exp = exp(-arg), exp(arg)
return (pos_exp + neg_exp)/(pos_exp - neg_exp)
def _eval_rewrite_as_exp(self, arg, **kwargs):
neg_exp, pos_exp = exp(-arg), exp(arg)
return (pos_exp + neg_exp)/(pos_exp - neg_exp)
def _eval_rewrite_as_sinh(self, arg, **kwargs):
return -I*sinh(pi*I/2 - arg, evaluate=False)/sinh(arg)
def _eval_rewrite_as_cosh(self, arg, **kwargs):
return -I*cosh(arg)/cosh(pi*I/2 - arg, evaluate=False)
def _eval_rewrite_as_tanh(self, arg, **kwargs):
return 1/tanh(arg)
def _eval_is_positive(self):
if self.args[0].is_extended_real:
return self.args[0].is_positive
def _eval_is_negative(self):
if self.args[0].is_extended_real:
return self.args[0].is_negative
def _eval_as_leading_term(self, x, logx=None, cdir=0):
from sympy.series.order import Order
arg = self.args[0].as_leading_term(x)
if x in arg.free_symbols and Order(1, x).contains(arg):
return 1/arg
else:
return self.func(arg)
def _eval_expand_trig(self, **hints):
arg = self.args[0]
if arg.is_Add:
CX = [coth(x, evaluate=False)._eval_expand_trig() for x in arg.args]
p = [[], []]
n = len(arg.args)
for i in range(n, -1, -1):
p[(n - i) % 2].append(symmetric_poly(i, CX))
return Add(*p[0])/Add(*p[1])
elif arg.is_Mul:
coeff, x = arg.as_coeff_Mul(rational=True)
if coeff.is_Integer and coeff > 1:
c = coth(x, evaluate=False)
p = [[], []]
for i in range(coeff, -1, -1):
p[(coeff - i) % 2].append(binomial(coeff, i)*c**i)
return Add(*p[0])/Add(*p[1])
return coth(arg)
class ReciprocalHyperbolicFunction(HyperbolicFunction):
"""Base class for reciprocal functions of hyperbolic functions. """
#To be defined in class
_reciprocal_of = None
_is_even: FuzzyBool = None
_is_odd: FuzzyBool = None
@classmethod
def eval(cls, arg):
if arg.could_extract_minus_sign():
if cls._is_even:
return cls(-arg)
if cls._is_odd:
return -cls(-arg)
t = cls._reciprocal_of.eval(arg)
if hasattr(arg, 'inverse') and arg.inverse() == cls:
return arg.args[0]
return 1/t if t is not None else t
def _call_reciprocal(self, method_name, *args, **kwargs):
# Calls method_name on _reciprocal_of
o = self._reciprocal_of(self.args[0])
return getattr(o, method_name)(*args, **kwargs)
def _calculate_reciprocal(self, method_name, *args, **kwargs):
# If calling method_name on _reciprocal_of returns a value != None
# then return the reciprocal of that value
t = self._call_reciprocal(method_name, *args, **kwargs)
return 1/t if t is not None else t
def _rewrite_reciprocal(self, method_name, arg):
# Special handling for rewrite functions. If reciprocal rewrite returns
# unmodified expression, then return None
t = self._call_reciprocal(method_name, arg)
if t is not None and t != self._reciprocal_of(arg):
return 1/t
def _eval_rewrite_as_exp(self, arg, **kwargs):
return self._rewrite_reciprocal("_eval_rewrite_as_exp", arg)
def _eval_rewrite_as_tractable(self, arg, limitvar=None, **kwargs):
return self._rewrite_reciprocal("_eval_rewrite_as_tractable", arg)
def _eval_rewrite_as_tanh(self, arg, **kwargs):
return self._rewrite_reciprocal("_eval_rewrite_as_tanh", arg)
def _eval_rewrite_as_coth(self, arg, **kwargs):
return self._rewrite_reciprocal("_eval_rewrite_as_coth", arg)
def as_real_imag(self, deep = True, **hints):
return (1 / self._reciprocal_of(self.args[0])).as_real_imag(deep, **hints)
def _eval_conjugate(self):
return self.func(self.args[0].conjugate())
def _eval_expand_complex(self, deep=True, **hints):
re_part, im_part = self.as_real_imag(deep=True, **hints)
return re_part + I*im_part
def _eval_expand_trig(self, **hints):
return self._calculate_reciprocal("_eval_expand_trig", **hints)
def _eval_as_leading_term(self, x, logx=None, cdir=0):
return (1/self._reciprocal_of(self.args[0]))._eval_as_leading_term(x)
def _eval_is_extended_real(self):
return self._reciprocal_of(self.args[0]).is_extended_real
def _eval_is_finite(self):
return (1/self._reciprocal_of(self.args[0])).is_finite
class csch(ReciprocalHyperbolicFunction):
r"""
``csch(x)`` is the hyperbolic cosecant of ``x``.
The hyperbolic cosecant function is $\frac{2}{e^x - e^{-x}}$
Examples
========
>>> from sympy import csch
>>> from sympy.abc import x
>>> csch(x)
csch(x)
See Also
========
sinh, cosh, tanh, sech, asinh, acosh
"""
_reciprocal_of = sinh
_is_odd = True
def fdiff(self, argindex=1):
"""
Returns the first derivative of this function
"""
if argindex == 1:
return -coth(self.args[0]) * csch(self.args[0])
else:
raise ArgumentIndexError(self, argindex)
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
"""
Returns the next term in the Taylor series expansion
"""
if n == 0:
return 1/sympify(x)
elif n < 0 or n % 2 == 0:
return S.Zero
else:
x = sympify(x)
B = bernoulli(n + 1)
F = factorial(n + 1)
return 2 * (1 - 2**n) * B/F * x**n
def _eval_rewrite_as_sin(self, arg, **kwargs):
return I / sin(I * arg, evaluate=False)
def _eval_rewrite_as_csc(self, arg, **kwargs):
return I * csc(I * arg, evaluate=False)
def _eval_rewrite_as_cosh(self, arg, **kwargs):
return I / cosh(arg + I * pi / 2, evaluate=False)
def _eval_rewrite_as_sinh(self, arg, **kwargs):
return 1 / sinh(arg)
def _eval_is_positive(self):
if self.args[0].is_extended_real:
return self.args[0].is_positive
def _eval_is_negative(self):
if self.args[0].is_extended_real:
return self.args[0].is_negative
class sech(ReciprocalHyperbolicFunction):
r"""
``sech(x)`` is the hyperbolic secant of ``x``.
The hyperbolic secant function is $\frac{2}{e^x + e^{-x}}$
Examples
========
>>> from sympy import sech
>>> from sympy.abc import x
>>> sech(x)
sech(x)
See Also
========
sinh, cosh, tanh, coth, csch, asinh, acosh
"""
_reciprocal_of = cosh
_is_even = True
def fdiff(self, argindex=1):
if argindex == 1:
return - tanh(self.args[0])*sech(self.args[0])
else:
raise ArgumentIndexError(self, argindex)
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
if n < 0 or n % 2 == 1:
return S.Zero
else:
x = sympify(x)
return euler(n) / factorial(n) * x**(n)
def _eval_rewrite_as_cos(self, arg, **kwargs):
return 1 / cos(I * arg, evaluate=False)
def _eval_rewrite_as_sec(self, arg, **kwargs):
return sec(I * arg, evaluate=False)
def _eval_rewrite_as_sinh(self, arg, **kwargs):
return I / sinh(arg + I * pi /2, evaluate=False)
def _eval_rewrite_as_cosh(self, arg, **kwargs):
return 1 / cosh(arg)
def _eval_is_positive(self):
if self.args[0].is_extended_real:
return True
###############################################################################
############################# HYPERBOLIC INVERSES #############################
###############################################################################
class InverseHyperbolicFunction(Function):
"""Base class for inverse hyperbolic functions."""
pass
class asinh(InverseHyperbolicFunction):
"""
``asinh(x)`` is the inverse hyperbolic sine of ``x``.
The inverse hyperbolic sine function.
Examples
========
>>> from sympy import asinh
>>> from sympy.abc import x
>>> asinh(x).diff(x)
1/sqrt(x**2 + 1)
>>> asinh(1)
log(1 + sqrt(2))
See Also
========
acosh, atanh, sinh
"""
def fdiff(self, argindex=1):
if argindex == 1:
return 1/sqrt(self.args[0]**2 + 1)
else:
raise ArgumentIndexError(self, argindex)
@classmethod
def eval(cls, arg):
if arg.is_Number:
if arg is S.NaN:
return S.NaN
elif arg is S.Infinity:
return S.Infinity
elif arg is S.NegativeInfinity:
return S.NegativeInfinity
elif arg.is_zero:
return S.Zero
elif arg is S.One:
return log(sqrt(2) + 1)
elif arg is S.NegativeOne:
return log(sqrt(2) - 1)
elif arg.is_negative:
return -cls(-arg)
else:
if arg is S.ComplexInfinity:
return S.ComplexInfinity
if arg.is_zero:
return S.Zero
i_coeff = _imaginary_unit_as_coefficient(arg)
if i_coeff is not None:
return I * asin(i_coeff)
else:
if arg.could_extract_minus_sign():
return -cls(-arg)
if isinstance(arg, sinh) and arg.args[0].is_number:
z = arg.args[0]
if z.is_real:
return z
r, i = match_real_imag(z)
if r is not None and i is not None:
f = floor((i + pi/2)/pi)
m = z - I*pi*f
even = f.is_even
if even is True:
return m
elif even is False:
return -m
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
if n < 0 or n % 2 == 0:
return S.Zero
else:
x = sympify(x)
if len(previous_terms) >= 2 and n > 2:
p = previous_terms[-2]
return -p * (n - 2)**2/(n*(n - 1)) * x**2
else:
k = (n - 1) // 2
R = RisingFactorial(S.Half, k)
F = factorial(k)
return S.NegativeOne**k * R / F * x**n / n
def _eval_as_leading_term(self, x, logx=None, cdir=0): # asinh
arg = self.args[0]
x0 = arg.subs(x, 0).cancel()
if x0.is_zero:
return arg.as_leading_term(x)
if x0 is S.NaN:
expr = self.func(arg.as_leading_term(x))
if expr.is_finite:
return expr
else:
return self
# Handling branch points
if x0 in (-I, I, S.ComplexInfinity):
return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir)
# Handling points lying on branch cuts (-I*oo, -I) U (I, I*oo)
if (1 + x0**2).is_negative:
ndir = arg.dir(x, cdir if cdir else 1)
if re(ndir).is_positive:
if im(x0).is_negative:
return -self.func(x0) - I*pi
elif re(ndir).is_negative:
if im(x0).is_positive:
return -self.func(x0) + I*pi
else:
return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir)
return self.func(x0)
def _eval_nseries(self, x, n, logx, cdir=0): # asinh
arg = self.args[0]
arg0 = arg.subs(x, 0)
# Handling branch points
if arg0 in (I, -I):
return self.rewrite(log)._eval_nseries(x, n, logx=logx, cdir=cdir)
res = Function._eval_nseries(self, x, n=n, logx=logx)
if arg0 is S.ComplexInfinity:
return res
# Handling points lying on branch cuts (-I*oo, -I) U (I, I*oo)
if (1 + arg0**2).is_negative:
ndir = arg.dir(x, cdir if cdir else 1)
if re(ndir).is_positive:
if im(arg0).is_negative:
return -res - I*pi
elif re(ndir).is_negative:
if im(arg0).is_positive:
return -res + I*pi
else:
return self.rewrite(log)._eval_nseries(x, n, logx=logx, cdir=cdir)
return res
def _eval_rewrite_as_log(self, x, **kwargs):
return log(x + sqrt(x**2 + 1))
_eval_rewrite_as_tractable = _eval_rewrite_as_log
def _eval_rewrite_as_atanh(self, x, **kwargs):
return atanh(x/sqrt(1 + x**2))
def _eval_rewrite_as_acosh(self, x, **kwargs):
ix = I*x
return I*(sqrt(1 - ix)/sqrt(ix - 1) * acosh(ix) - pi/2)
def _eval_rewrite_as_asin(self, x, **kwargs):
return -I * asin(I * x, evaluate=False)
def _eval_rewrite_as_acos(self, x, **kwargs):
return I * acos(I * x, evaluate=False) - I*pi/2
def inverse(self, argindex=1):
"""
Returns the inverse of this function.
"""
return sinh
def _eval_is_zero(self):
return self.args[0].is_zero
def _eval_is_extended_real(self):
return self.args[0].is_extended_real
def _eval_is_finite(self):
return self.args[0].is_finite
class acosh(InverseHyperbolicFunction):
"""
``acosh(x)`` is the inverse hyperbolic cosine of ``x``.
The inverse hyperbolic cosine function.
Examples
========
>>> from sympy import acosh
>>> from sympy.abc import x
>>> acosh(x).diff(x)
1/(sqrt(x - 1)*sqrt(x + 1))
>>> acosh(1)
0
See Also
========
asinh, atanh, cosh
"""
def fdiff(self, argindex=1):
if argindex == 1:
arg = self.args[0]
return 1/(sqrt(arg - 1)*sqrt(arg + 1))
else:
raise ArgumentIndexError(self, argindex)
@classmethod
def eval(cls, arg):
if arg.is_Number:
if arg is S.NaN:
return S.NaN
elif arg is S.Infinity:
return S.Infinity
elif arg is S.NegativeInfinity:
return S.Infinity
elif arg.is_zero:
return pi*I / 2
elif arg is S.One:
return S.Zero
elif arg is S.NegativeOne:
return pi*I
if arg.is_number:
cst_table = _acosh_table()
if arg in cst_table:
if arg.is_extended_real:
return cst_table[arg]*I
return cst_table[arg]
if arg is S.ComplexInfinity:
return S.ComplexInfinity
if arg == I*S.Infinity:
return S.Infinity + I*pi/2
if arg == -I*S.Infinity:
return S.Infinity - I*pi/2
if arg.is_zero:
return pi*I*S.Half
if isinstance(arg, cosh) and arg.args[0].is_number:
z = arg.args[0]
if z.is_real:
return Abs(z)
r, i = match_real_imag(z)
if r is not None and i is not None:
f = floor(i/pi)
m = z - I*pi*f
even = f.is_even
if even is True:
if r.is_nonnegative:
return m
elif r.is_negative:
return -m
elif even is False:
m -= I*pi
if r.is_nonpositive:
return -m
elif r.is_positive:
return m
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
if n == 0:
return I*pi/2
elif n < 0 or n % 2 == 0:
return S.Zero
else:
x = sympify(x)
if len(previous_terms) >= 2 and n > 2:
p = previous_terms[-2]
return p * (n - 2)**2/(n*(n - 1)) * x**2
else:
k = (n - 1) // 2
R = RisingFactorial(S.Half, k)
F = factorial(k)
return -R / F * I * x**n / n
def _eval_as_leading_term(self, x, logx=None, cdir=0): # acosh
arg = self.args[0]
x0 = arg.subs(x, 0).cancel()
# Handling branch points
if x0 in (-S.One, S.Zero, S.One, S.ComplexInfinity):
return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir)
if x0 is S.NaN:
expr = self.func(arg.as_leading_term(x))
if expr.is_finite:
return expr
else:
return self
# Handling points lying on branch cuts (-oo, 1)
if (x0 - 1).is_negative:
ndir = arg.dir(x, cdir if cdir else 1)
if im(ndir).is_negative:
if (x0 + 1).is_negative:
return self.func(x0) - 2*I*pi
return -self.func(x0)
elif not im(ndir).is_positive:
return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir)
return self.func(x0)
def _eval_nseries(self, x, n, logx, cdir=0): # acosh
arg = self.args[0]
arg0 = arg.subs(x, 0)
# Handling branch points
if arg0 in (S.One, S.NegativeOne):
return self.rewrite(log)._eval_nseries(x, n, logx=logx, cdir=cdir)
res = Function._eval_nseries(self, x, n=n, logx=logx)
if arg0 is S.ComplexInfinity:
return res
# Handling points lying on branch cuts (-oo, 1)
if (arg0 - 1).is_negative:
ndir = arg.dir(x, cdir if cdir else 1)
if im(ndir).is_negative:
if (arg0 + 1).is_negative:
return res - 2*I*pi
return -res
elif not im(ndir).is_positive:
return self.rewrite(log)._eval_nseries(x, n, logx=logx, cdir=cdir)
return res
def _eval_rewrite_as_log(self, x, **kwargs):
return log(x + sqrt(x + 1) * sqrt(x - 1))
_eval_rewrite_as_tractable = _eval_rewrite_as_log
def _eval_rewrite_as_acos(self, x, **kwargs):
return sqrt(x - 1)/sqrt(1 - x) * acos(x)
def _eval_rewrite_as_asin(self, x, **kwargs):
return sqrt(x - 1)/sqrt(1 - x) * (pi/2 - asin(x))
def _eval_rewrite_as_asinh(self, x, **kwargs):
return sqrt(x - 1)/sqrt(1 - x) * (pi/2 + I*asinh(I*x, evaluate=False))
def _eval_rewrite_as_atanh(self, x, **kwargs):
sxm1 = sqrt(x - 1)
s1mx = sqrt(1 - x)
sx2m1 = sqrt(x**2 - 1)
return (pi/2*sxm1/s1mx*(1 - x * sqrt(1/x**2)) +
sxm1*sqrt(x + 1)/sx2m1 * atanh(sx2m1/x))
def inverse(self, argindex=1):
"""
Returns the inverse of this function.
"""
return cosh
def _eval_is_zero(self):
if (self.args[0] - 1).is_zero:
return True
def _eval_is_extended_real(self):
return fuzzy_and([self.args[0].is_extended_real, (self.args[0] - 1).is_extended_nonnegative])
def _eval_is_finite(self):
return self.args[0].is_finite
class atanh(InverseHyperbolicFunction):
"""
``atanh(x)`` is the inverse hyperbolic tangent of ``x``.
The inverse hyperbolic tangent function.
Examples
========
>>> from sympy import atanh
>>> from sympy.abc import x
>>> atanh(x).diff(x)
1/(1 - x**2)
See Also
========
asinh, acosh, tanh
"""
def fdiff(self, argindex=1):
if argindex == 1:
return 1/(1 - self.args[0]**2)
else:
raise ArgumentIndexError(self, argindex)
@classmethod
def eval(cls, arg):
if arg.is_Number:
if arg is S.NaN:
return S.NaN
elif arg.is_zero:
return S.Zero
elif arg is S.One:
return S.Infinity
elif arg is S.NegativeOne:
return S.NegativeInfinity
elif arg is S.Infinity:
return -I * atan(arg)
elif arg is S.NegativeInfinity:
return I * atan(-arg)
elif arg.is_negative:
return -cls(-arg)
else:
if arg is S.ComplexInfinity:
from sympy.calculus.accumulationbounds import AccumBounds
return I*AccumBounds(-pi/2, pi/2)
i_coeff = _imaginary_unit_as_coefficient(arg)
if i_coeff is not None:
return I * atan(i_coeff)
else:
if arg.could_extract_minus_sign():
return -cls(-arg)
if arg.is_zero:
return S.Zero
if isinstance(arg, tanh) and arg.args[0].is_number:
z = arg.args[0]
if z.is_real:
return z
r, i = match_real_imag(z)
if r is not None and i is not None:
f = floor(2*i/pi)
even = f.is_even
m = z - I*f*pi/2
if even is True:
return m
elif even is False:
return m - I*pi/2
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
if n < 0 or n % 2 == 0:
return S.Zero
else:
x = sympify(x)
return x**n / n
def _eval_as_leading_term(self, x, logx=None, cdir=0): # atanh
arg = self.args[0]
x0 = arg.subs(x, 0).cancel()
if x0.is_zero:
return arg.as_leading_term(x)
if x0 is S.NaN:
expr = self.func(arg.as_leading_term(x))
if expr.is_finite:
return expr
else:
return self
# Handling branch points
if x0 in (-S.One, S.One, S.ComplexInfinity):
return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir)
# Handling points lying on branch cuts (-oo, -1] U [1, oo)
if (1 - x0**2).is_negative:
ndir = arg.dir(x, cdir if cdir else 1)
if im(ndir).is_negative:
if x0.is_negative:
return self.func(x0) - I*pi
elif im(ndir).is_positive:
if x0.is_positive:
return self.func(x0) + I*pi
else:
return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir)
return self.func(x0)
def _eval_nseries(self, x, n, logx, cdir=0): # atanh
arg = self.args[0]
arg0 = arg.subs(x, 0)
# Handling branch points
if arg0 in (S.One, S.NegativeOne):
return self.rewrite(log)._eval_nseries(x, n, logx=logx, cdir=cdir)
res = Function._eval_nseries(self, x, n=n, logx=logx)
if arg0 is S.ComplexInfinity:
return res
# Handling points lying on branch cuts (-oo, -1] U [1, oo)
if (1 - arg0**2).is_negative:
ndir = arg.dir(x, cdir if cdir else 1)
if im(ndir).is_negative:
if arg0.is_negative:
return res - I*pi
elif im(ndir).is_positive:
if arg0.is_positive:
return res + I*pi
else:
return self.rewrite(log)._eval_nseries(x, n, logx=logx, cdir=cdir)
return res
def _eval_rewrite_as_log(self, x, **kwargs):
return (log(1 + x) - log(1 - x)) / 2
_eval_rewrite_as_tractable = _eval_rewrite_as_log
def _eval_rewrite_as_asinh(self, x, **kwargs):
f = sqrt(1/(x**2 - 1))
return (pi*x/(2*sqrt(-x**2)) -
sqrt(-x)*sqrt(1 - x**2)/sqrt(x)*f*asinh(f))
def _eval_is_zero(self):
if self.args[0].is_zero:
return True
def _eval_is_extended_real(self):
return fuzzy_and([self.args[0].is_extended_real, (1 - self.args[0]).is_nonnegative, (self.args[0] + 1).is_nonnegative])
def _eval_is_finite(self):
return fuzzy_not(fuzzy_or([(self.args[0] - 1).is_zero, (self.args[0] + 1).is_zero]))
def _eval_is_imaginary(self):
return self.args[0].is_imaginary
def inverse(self, argindex=1):
"""
Returns the inverse of this function.
"""
return tanh
class acoth(InverseHyperbolicFunction):
"""
``acoth(x)`` is the inverse hyperbolic cotangent of ``x``.
The inverse hyperbolic cotangent function.
Examples
========
>>> from sympy import acoth
>>> from sympy.abc import x
>>> acoth(x).diff(x)
1/(1 - x**2)
See Also
========
asinh, acosh, coth
"""
def fdiff(self, argindex=1):
if argindex == 1:
return 1/(1 - self.args[0]**2)
else:
raise ArgumentIndexError(self, argindex)
@classmethod
def eval(cls, arg):
if arg.is_Number:
if arg is S.NaN:
return S.NaN
elif arg is S.Infinity:
return S.Zero
elif arg is S.NegativeInfinity:
return S.Zero
elif arg.is_zero:
return pi*I / 2
elif arg is S.One:
return S.Infinity
elif arg is S.NegativeOne:
return S.NegativeInfinity
elif arg.is_negative:
return -cls(-arg)
else:
if arg is S.ComplexInfinity:
return S.Zero
i_coeff = _imaginary_unit_as_coefficient(arg)
if i_coeff is not None:
return -I * acot(i_coeff)
else:
if arg.could_extract_minus_sign():
return -cls(-arg)
if arg.is_zero:
return pi*I*S.Half
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
if n == 0:
return -I*pi/2
elif n < 0 or n % 2 == 0:
return S.Zero
else:
x = sympify(x)
return x**n / n
def _eval_as_leading_term(self, x, logx=None, cdir=0): # acoth
arg = self.args[0]
x0 = arg.subs(x, 0).cancel()
if x0 is S.ComplexInfinity:
return (1/arg).as_leading_term(x)
if x0 is S.NaN:
expr = self.func(arg.as_leading_term(x))
if expr.is_finite:
return expr
else:
return self
# Handling branch points
if x0 in (-S.One, S.One, S.Zero):
return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir)
# Handling points lying on branch cuts [-1, 1]
if x0.is_real and (1 - x0**2).is_positive:
ndir = arg.dir(x, cdir if cdir else 1)
if im(ndir).is_negative:
if x0.is_positive:
return self.func(x0) + I*pi
elif im(ndir).is_positive:
if x0.is_negative:
return self.func(x0) - I*pi
else:
return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir)
return self.func(x0)
def _eval_nseries(self, x, n, logx, cdir=0): # acoth
arg = self.args[0]
arg0 = arg.subs(x, 0)
# Handling branch points
if arg0 in (S.One, S.NegativeOne):
return self.rewrite(log)._eval_nseries(x, n, logx=logx, cdir=cdir)
res = Function._eval_nseries(self, x, n=n, logx=logx)
if arg0 is S.ComplexInfinity:
return res
# Handling points lying on branch cuts [-1, 1]
if arg0.is_real and (1 - arg0**2).is_positive:
ndir = arg.dir(x, cdir if cdir else 1)
if im(ndir).is_negative:
if arg0.is_positive:
return res + I*pi
elif im(ndir).is_positive:
if arg0.is_negative:
return res - I*pi
else:
return self.rewrite(log)._eval_nseries(x, n, logx=logx, cdir=cdir)
return res
def _eval_rewrite_as_log(self, x, **kwargs):
return (log(1 + 1/x) - log(1 - 1/x)) / 2
_eval_rewrite_as_tractable = _eval_rewrite_as_log
def _eval_rewrite_as_atanh(self, x, **kwargs):
return atanh(1/x)
def _eval_rewrite_as_asinh(self, x, **kwargs):
return (pi*I/2*(sqrt((x - 1)/x)*sqrt(x/(x - 1)) - sqrt(1 + 1/x)*sqrt(x/(x + 1))) +
x*sqrt(1/x**2)*asinh(sqrt(1/(x**2 - 1))))
def inverse(self, argindex=1):
"""
Returns the inverse of this function.
"""
return coth
def _eval_is_extended_real(self):
return fuzzy_and([self.args[0].is_extended_real, fuzzy_or([(self.args[0] - 1).is_extended_nonnegative, (self.args[0] + 1).is_extended_nonpositive])])
def _eval_is_finite(self):
return fuzzy_not(fuzzy_or([(self.args[0] - 1).is_zero, (self.args[0] + 1).is_zero]))
class asech(InverseHyperbolicFunction):
"""
``asech(x)`` is the inverse hyperbolic secant of ``x``.
The inverse hyperbolic secant function.
Examples
========
>>> from sympy import asech, sqrt, S
>>> from sympy.abc import x
>>> asech(x).diff(x)
-1/(x*sqrt(1 - x**2))
>>> asech(1).diff(x)
0
>>> asech(1)
0
>>> asech(S(2))
I*pi/3
>>> asech(-sqrt(2))
3*I*pi/4
>>> asech((sqrt(6) - sqrt(2)))
I*pi/12
See Also
========
asinh, atanh, cosh, acoth
References
==========
.. [1] https://en.wikipedia.org/wiki/Hyperbolic_function
.. [2] https://dlmf.nist.gov/4.37
.. [3] https://functions.wolfram.com/ElementaryFunctions/ArcSech/
"""
def fdiff(self, argindex=1):
if argindex == 1:
z = self.args[0]
return -1/(z*sqrt(1 - z**2))
else:
raise ArgumentIndexError(self, argindex)
@classmethod
def eval(cls, arg):
if arg.is_Number:
if arg is S.NaN:
return S.NaN
elif arg is S.Infinity:
return pi*I / 2
elif arg is S.NegativeInfinity:
return pi*I / 2
elif arg.is_zero:
return S.Infinity
elif arg is S.One:
return S.Zero
elif arg is S.NegativeOne:
return pi*I
if arg.is_number:
cst_table = _asech_table()
if arg in cst_table:
if arg.is_extended_real:
return cst_table[arg]*I
return cst_table[arg]
if arg is S.ComplexInfinity:
from sympy.calculus.accumulationbounds import AccumBounds
return I*AccumBounds(-pi/2, pi/2)
if arg.is_zero:
return S.Infinity
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
if n == 0:
return log(2 / x)
elif n < 0 or n % 2 == 1:
return S.Zero
else:
x = sympify(x)
if len(previous_terms) > 2 and n > 2:
p = previous_terms[-2]
return p * ((n - 1)*(n-2)) * x**2/(4 * (n//2)**2)
else:
k = n // 2
R = RisingFactorial(S.Half, k) * n
F = factorial(k) * n // 2 * n // 2
return -1 * R / F * x**n / 4
def _eval_as_leading_term(self, x, logx=None, cdir=0): # asech
arg = self.args[0]
x0 = arg.subs(x, 0).cancel()
# Handling branch points
if x0 in (-S.One, S.Zero, S.One, S.ComplexInfinity):
return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir)
if x0 is S.NaN:
expr = self.func(arg.as_leading_term(x))
if expr.is_finite:
return expr
else:
return self
# Handling points lying on branch cuts (-oo, 0] U (1, oo)
if x0.is_negative or (1 - x0).is_negative:
ndir = arg.dir(x, cdir if cdir else 1)
if im(ndir).is_positive:
if x0.is_positive or (x0 + 1).is_negative:
return -self.func(x0)
return self.func(x0) - 2*I*pi
elif not im(ndir).is_negative:
return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir)
return self.func(x0)
def _eval_nseries(self, x, n, logx, cdir=0): # asech
from sympy.series.order import O
arg = self.args[0]
arg0 = arg.subs(x, 0)
# Handling branch points
if arg0 is S.One:
t = Dummy('t', positive=True)
ser = asech(S.One - t**2).rewrite(log).nseries(t, 0, 2*n)
arg1 = S.One - self.args[0]
f = arg1.as_leading_term(x)
g = (arg1 - f)/ f
if not g.is_meromorphic(x, 0): # cannot be expanded
return O(1) if n == 0 else O(sqrt(x))
res1 = sqrt(S.One + g)._eval_nseries(x, n=n, logx=logx)
res = (res1.removeO()*sqrt(f)).expand()
return ser.removeO().subs(t, res).expand().powsimp() + O(x**n, x)
if arg0 is S.NegativeOne:
t = Dummy('t', positive=True)
ser = asech(S.NegativeOne + t**2).rewrite(log).nseries(t, 0, 2*n)
arg1 = S.One + self.args[0]
f = arg1.as_leading_term(x)
g = (arg1 - f)/ f
if not g.is_meromorphic(x, 0): # cannot be expanded
return O(1) if n == 0 else I*pi + O(sqrt(x))
res1 = sqrt(S.One + g)._eval_nseries(x, n=n, logx=logx)
res = (res1.removeO()*sqrt(f)).expand()
return ser.removeO().subs(t, res).expand().powsimp() + O(x**n, x)
res = Function._eval_nseries(self, x, n=n, logx=logx)
if arg0 is S.ComplexInfinity:
return res
# Handling points lying on branch cuts (-oo, 0] U (1, oo)
if arg0.is_negative or (1 - arg0).is_negative:
ndir = arg.dir(x, cdir if cdir else 1)
if im(ndir).is_positive:
if arg0.is_positive or (arg0 + 1).is_negative:
return -res
return res - 2*I*pi
elif not im(ndir).is_negative:
return self.rewrite(log)._eval_nseries(x, n, logx=logx, cdir=cdir)
return res
def inverse(self, argindex=1):
"""
Returns the inverse of this function.
"""
return sech
def _eval_rewrite_as_log(self, arg, **kwargs):
return log(1/arg + sqrt(1/arg - 1) * sqrt(1/arg + 1))
_eval_rewrite_as_tractable = _eval_rewrite_as_log
def _eval_rewrite_as_acosh(self, arg, **kwargs):
return acosh(1/arg)
def _eval_rewrite_as_asinh(self, arg, **kwargs):
return sqrt(1/arg - 1)/sqrt(1 - 1/arg)*(I*asinh(I/arg, evaluate=False)
+ pi*S.Half)
def _eval_rewrite_as_atanh(self, x, **kwargs):
return (I*pi*(1 - sqrt(x)*sqrt(1/x) - I/2*sqrt(-x)/sqrt(x) - I/2*sqrt(x**2)/sqrt(-x**2))
+ sqrt(1/(x + 1))*sqrt(x + 1)*atanh(sqrt(1 - x**2)))
def _eval_rewrite_as_acsch(self, x, **kwargs):
return sqrt(1/x - 1)/sqrt(1 - 1/x)*(pi/2 - I*acsch(I*x, evaluate=False))
def _eval_is_extended_real(self):
return fuzzy_and([self.args[0].is_extended_real, self.args[0].is_nonnegative, (1 - self.args[0]).is_nonnegative])
def _eval_is_finite(self):
return fuzzy_not(self.args[0].is_zero)
class acsch(InverseHyperbolicFunction):
"""
``acsch(x)`` is the inverse hyperbolic cosecant of ``x``.
The inverse hyperbolic cosecant function.
Examples
========
>>> from sympy import acsch, sqrt, I
>>> from sympy.abc import x
>>> acsch(x).diff(x)
-1/(x**2*sqrt(1 + x**(-2)))
>>> acsch(1).diff(x)
0
>>> acsch(1)
log(1 + sqrt(2))
>>> acsch(I)
-I*pi/2
>>> acsch(-2*I)
I*pi/6
>>> acsch(I*(sqrt(6) - sqrt(2)))
-5*I*pi/12
See Also
========
asinh
References
==========
.. [1] https://en.wikipedia.org/wiki/Hyperbolic_function
.. [2] https://dlmf.nist.gov/4.37
.. [3] https://functions.wolfram.com/ElementaryFunctions/ArcCsch/
"""
def fdiff(self, argindex=1):
if argindex == 1:
z = self.args[0]
return -1/(z**2*sqrt(1 + 1/z**2))
else:
raise ArgumentIndexError(self, argindex)
@classmethod
def eval(cls, arg):
if arg.is_Number:
if arg is S.NaN:
return S.NaN
elif arg is S.Infinity:
return S.Zero
elif arg is S.NegativeInfinity:
return S.Zero
elif arg.is_zero:
return S.ComplexInfinity
elif arg is S.One:
return log(1 + sqrt(2))
elif arg is S.NegativeOne:
return - log(1 + sqrt(2))
if arg.is_number:
cst_table = _acsch_table()
if arg in cst_table:
return cst_table[arg]*I
if arg is S.ComplexInfinity:
return S.Zero
if arg.is_infinite:
return S.Zero
if arg.is_zero:
return S.ComplexInfinity
if arg.could_extract_minus_sign():
return -cls(-arg)
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
if n == 0:
return log(2 / x)
elif n < 0 or n % 2 == 1:
return S.Zero
else:
x = sympify(x)
if len(previous_terms) > 2 and n > 2:
p = previous_terms[-2]
return -p * ((n - 1)*(n-2)) * x**2/(4 * (n//2)**2)
else:
k = n // 2
R = RisingFactorial(S.Half, k) * n
F = factorial(k) * n // 2 * n // 2
return S.NegativeOne**(k +1) * R / F * x**n / 4
def _eval_as_leading_term(self, x, logx=None, cdir=0): # acsch
arg = self.args[0]
x0 = arg.subs(x, 0).cancel()
# Handling branch points
if x0 in (-I, I, S.Zero):
return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir)
if x0 is S.NaN:
expr = self.func(arg.as_leading_term(x))
if expr.is_finite:
return expr
else:
return self
if x0 is S.ComplexInfinity:
return (1/arg).as_leading_term(x)
# Handling points lying on branch cuts (-I, I)
if x0.is_imaginary and (1 + x0**2).is_positive:
ndir = arg.dir(x, cdir if cdir else 1)
if re(ndir).is_positive:
if im(x0).is_positive:
return -self.func(x0) - I*pi
elif re(ndir).is_negative:
if im(x0).is_negative:
return -self.func(x0) + I*pi
else:
return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir)
return self.func(x0)
def _eval_nseries(self, x, n, logx, cdir=0): # acsch
from sympy.series.order import O
arg = self.args[0]
arg0 = arg.subs(x, 0)
# Handling branch points
if arg0 is I:
t = Dummy('t', positive=True)
ser = acsch(I + t**2).rewrite(log).nseries(t, 0, 2*n)
arg1 = -I + self.args[0]
f = arg1.as_leading_term(x)
g = (arg1 - f)/ f
if not g.is_meromorphic(x, 0): # cannot be expanded
return O(1) if n == 0 else -I*pi/2 + O(sqrt(x))
res1 = sqrt(S.One + g)._eval_nseries(x, n=n, logx=logx)
res = (res1.removeO()*sqrt(f)).expand()
res = ser.removeO().subs(t, res).expand().powsimp() + O(x**n, x)
return res
if arg0 == S.NegativeOne*I:
t = Dummy('t', positive=True)
ser = acsch(-I + t**2).rewrite(log).nseries(t, 0, 2*n)
arg1 = I + self.args[0]
f = arg1.as_leading_term(x)
g = (arg1 - f)/ f
if not g.is_meromorphic(x, 0): # cannot be expanded
return O(1) if n == 0 else I*pi/2 + O(sqrt(x))
res1 = sqrt(S.One + g)._eval_nseries(x, n=n, logx=logx)
res = (res1.removeO()*sqrt(f)).expand()
return ser.removeO().subs(t, res).expand().powsimp() + O(x**n, x)
res = Function._eval_nseries(self, x, n=n, logx=logx)
if arg0 is S.ComplexInfinity:
return res
# Handling points lying on branch cuts (-I, I)
if arg0.is_imaginary and (1 + arg0**2).is_positive:
ndir = self.args[0].dir(x, cdir if cdir else 1)
if re(ndir).is_positive:
if im(arg0).is_positive:
return -res - I*pi
elif re(ndir).is_negative:
if im(arg0).is_negative:
return -res + I*pi
else:
return self.rewrite(log)._eval_nseries(x, n, logx=logx, cdir=cdir)
return res
def inverse(self, argindex=1):
"""
Returns the inverse of this function.
"""
return csch
def _eval_rewrite_as_log(self, arg, **kwargs):
return log(1/arg + sqrt(1/arg**2 + 1))
_eval_rewrite_as_tractable = _eval_rewrite_as_log
def _eval_rewrite_as_asinh(self, arg, **kwargs):
return asinh(1/arg)
def _eval_rewrite_as_acosh(self, arg, **kwargs):
return I*(sqrt(1 - I/arg)/sqrt(I/arg - 1)*
acosh(I/arg, evaluate=False) - pi*S.Half)
def _eval_rewrite_as_atanh(self, arg, **kwargs):
arg2 = arg**2
arg2p1 = arg2 + 1
return sqrt(-arg2)/arg*(pi*S.Half -
sqrt(-arg2p1**2)/arg2p1*atanh(sqrt(arg2p1)))
def _eval_is_zero(self):
return self.args[0].is_infinite
def _eval_is_extended_real(self):
return self.args[0].is_extended_real
def _eval_is_finite(self):
return fuzzy_not(self.args[0].is_zero)
PK ]ZZZ�� ��M �M & sympy/functions/elementary/integers.pyfrom typing import Tuple as tTuple
from sympy.core.basic import Basic
from sympy.core.expr import Expr
from sympy.core import Add, S
from sympy.core.evalf import get_integer_part, PrecisionExhausted
from sympy.core.function import Function
from sympy.core.logic import fuzzy_or
from sympy.core.numbers import Integer, int_valued
from sympy.core.relational import Gt, Lt, Ge, Le, Relational, is_eq
from sympy.core.sympify import _sympify
from sympy.functions.elementary.complexes import im, re
from sympy.multipledispatch import dispatch
###############################################################################
######################### FLOOR and CEILING FUNCTIONS #########################
###############################################################################
class RoundFunction(Function):
"""Abstract base class for rounding functions."""
args: tTuple[Expr]
@classmethod
def eval(cls, arg):
v = cls._eval_number(arg)
if v is not None:
return v
if arg.is_integer or arg.is_finite is False:
return arg
if arg.is_imaginary or (S.ImaginaryUnit*arg).is_real:
i = im(arg)
if not i.has(S.ImaginaryUnit):
return cls(i)*S.ImaginaryUnit
return cls(arg, evaluate=False)
# Integral, numerical, symbolic part
ipart = npart = spart = S.Zero
# Extract integral (or complex integral) terms
intof = lambda x: int(x) if int_valued(x) else (
x if x.is_integer else None)
for t in Add.make_args(arg):
if t.is_imaginary and (i := intof(im(t))) is not None:
ipart += i*S.ImaginaryUnit
elif (i := intof(t)) is not None:
ipart += i
elif t.is_number:
npart += t
else:
spart += t
if not (npart or spart):
return ipart
# Evaluate npart numerically if independent of spart
if npart and (
not spart or
npart.is_real and (spart.is_imaginary or (S.ImaginaryUnit*spart).is_real) or
npart.is_imaginary and spart.is_real):
try:
r, i = get_integer_part(
npart, cls._dir, {}, return_ints=True)
ipart += Integer(r) + Integer(i)*S.ImaginaryUnit
npart = S.Zero
except (PrecisionExhausted, NotImplementedError):
pass
spart += npart
if not spart:
return ipart
elif spart.is_imaginary or (S.ImaginaryUnit*spart).is_real:
return ipart + cls(im(spart), evaluate=False)*S.ImaginaryUnit
elif isinstance(spart, (floor, ceiling)):
return ipart + spart
else:
return ipart + cls(spart, evaluate=False)
@classmethod
def _eval_number(cls, arg):
raise NotImplementedError()
def _eval_is_finite(self):
return self.args[0].is_finite
def _eval_is_real(self):
return self.args[0].is_real
def _eval_is_integer(self):
return self.args[0].is_real
class floor(RoundFunction):
"""
Floor is a univariate function which returns the largest integer
value not greater than its argument. This implementation
generalizes floor to complex numbers by taking the floor of the
real and imaginary parts separately.
Examples
========
>>> from sympy import floor, E, I, S, Float, Rational
>>> floor(17)
17
>>> floor(Rational(23, 10))
2
>>> floor(2*E)
5
>>> floor(-Float(0.567))
-1
>>> floor(-I/2)
-I
>>> floor(S(5)/2 + 5*I/2)
2 + 2*I
See Also
========
sympy.functions.elementary.integers.ceiling
References
==========
.. [1] "Concrete mathematics" by Graham, pp. 87
.. [2] https://mathworld.wolfram.com/FloorFunction.html
"""
_dir = -1
@classmethod
def _eval_number(cls, arg):
if arg.is_Number:
return arg.floor()
elif any(isinstance(i, j)
for i in (arg, -arg) for j in (floor, ceiling)):
return arg
if arg.is_NumberSymbol:
return arg.approximation_interval(Integer)[0]
def _eval_as_leading_term(self, x, logx=None, cdir=0):
from sympy.calculus.accumulationbounds import AccumBounds
arg = self.args[0]
arg0 = arg.subs(x, 0)
r = self.subs(x, 0)
if arg0 is S.NaN or isinstance(arg0, AccumBounds):
arg0 = arg.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
r = floor(arg0)
if arg0.is_finite:
if arg0 == r:
ndir = arg.dir(x, cdir=cdir if cdir != 0 else 1)
if ndir.is_negative:
return r - 1
elif ndir.is_positive:
return r
else:
raise NotImplementedError("Not sure of sign of %s" % ndir)
else:
return r
return arg.as_leading_term(x, logx=logx, cdir=cdir)
def _eval_nseries(self, x, n, logx, cdir=0):
arg = self.args[0]
arg0 = arg.subs(x, 0)
r = self.subs(x, 0)
if arg0 is S.NaN:
arg0 = arg.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
r = floor(arg0)
if arg0.is_infinite:
from sympy.calculus.accumulationbounds import AccumBounds
from sympy.series.order import Order
s = arg._eval_nseries(x, n, logx, cdir)
o = Order(1, (x, 0)) if n <= 0 else AccumBounds(-1, 0)
return s + o
if arg0 == r:
ndir = arg.dir(x, cdir=cdir if cdir != 0 else 1)
if ndir.is_negative:
return r - 1
elif ndir.is_positive:
return r
else:
raise NotImplementedError("Not sure of sign of %s" % ndir)
else:
return r
def _eval_is_negative(self):
return self.args[0].is_negative
def _eval_is_nonnegative(self):
return self.args[0].is_nonnegative
def _eval_rewrite_as_ceiling(self, arg, **kwargs):
return -ceiling(-arg)
def _eval_rewrite_as_frac(self, arg, **kwargs):
return arg - frac(arg)
def __le__(self, other):
other = S(other)
if self.args[0].is_real:
if other.is_integer:
return self.args[0] < other + 1
if other.is_number and other.is_real:
return self.args[0] < ceiling(other)
if self.args[0] == other and other.is_real:
return S.true
if other is S.Infinity and self.is_finite:
return S.true
return Le(self, other, evaluate=False)
def __ge__(self, other):
other = S(other)
if self.args[0].is_real:
if other.is_integer:
return self.args[0] >= other
if other.is_number and other.is_real:
return self.args[0] >= ceiling(other)
if self.args[0] == other and other.is_real:
return S.false
if other is S.NegativeInfinity and self.is_finite:
return S.true
return Ge(self, other, evaluate=False)
def __gt__(self, other):
other = S(other)
if self.args[0].is_real:
if other.is_integer:
return self.args[0] >= other + 1
if other.is_number and other.is_real:
return self.args[0] >= ceiling(other)
if self.args[0] == other and other.is_real:
return S.false
if other is S.NegativeInfinity and self.is_finite:
return S.true
return Gt(self, other, evaluate=False)
def __lt__(self, other):
other = S(other)
if self.args[0].is_real:
if other.is_integer:
return self.args[0] < other
if other.is_number and other.is_real:
return self.args[0] < ceiling(other)
if self.args[0] == other and other.is_real:
return S.false
if other is S.Infinity and self.is_finite:
return S.true
return Lt(self, other, evaluate=False)
@dispatch(floor, Expr)
def _eval_is_eq(lhs, rhs): # noqa:F811
return is_eq(lhs.rewrite(ceiling), rhs) or \
is_eq(lhs.rewrite(frac),rhs)
class ceiling(RoundFunction):
"""
Ceiling is a univariate function which returns the smallest integer
value not less than its argument. This implementation
generalizes ceiling to complex numbers by taking the ceiling of the
real and imaginary parts separately.
Examples
========
>>> from sympy import ceiling, E, I, S, Float, Rational
>>> ceiling(17)
17
>>> ceiling(Rational(23, 10))
3
>>> ceiling(2*E)
6
>>> ceiling(-Float(0.567))
0
>>> ceiling(I/2)
I
>>> ceiling(S(5)/2 + 5*I/2)
3 + 3*I
See Also
========
sympy.functions.elementary.integers.floor
References
==========
.. [1] "Concrete mathematics" by Graham, pp. 87
.. [2] https://mathworld.wolfram.com/CeilingFunction.html
"""
_dir = 1
@classmethod
def _eval_number(cls, arg):
if arg.is_Number:
return arg.ceiling()
elif any(isinstance(i, j)
for i in (arg, -arg) for j in (floor, ceiling)):
return arg
if arg.is_NumberSymbol:
return arg.approximation_interval(Integer)[1]
def _eval_as_leading_term(self, x, logx=None, cdir=0):
from sympy.calculus.accumulationbounds import AccumBounds
arg = self.args[0]
arg0 = arg.subs(x, 0)
r = self.subs(x, 0)
if arg0 is S.NaN or isinstance(arg0, AccumBounds):
arg0 = arg.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
r = ceiling(arg0)
if arg0.is_finite:
if arg0 == r:
ndir = arg.dir(x, cdir=cdir if cdir != 0 else 1)
if ndir.is_negative:
return r
elif ndir.is_positive:
return r + 1
else:
raise NotImplementedError("Not sure of sign of %s" % ndir)
else:
return r
return arg.as_leading_term(x, logx=logx, cdir=cdir)
def _eval_nseries(self, x, n, logx, cdir=0):
arg = self.args[0]
arg0 = arg.subs(x, 0)
r = self.subs(x, 0)
if arg0 is S.NaN:
arg0 = arg.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
r = ceiling(arg0)
if arg0.is_infinite:
from sympy.calculus.accumulationbounds import AccumBounds
from sympy.series.order import Order
s = arg._eval_nseries(x, n, logx, cdir)
o = Order(1, (x, 0)) if n <= 0 else AccumBounds(0, 1)
return s + o
if arg0 == r:
ndir = arg.dir(x, cdir=cdir if cdir != 0 else 1)
if ndir.is_negative:
return r
elif ndir.is_positive:
return r + 1
else:
raise NotImplementedError("Not sure of sign of %s" % ndir)
else:
return r
def _eval_rewrite_as_floor(self, arg, **kwargs):
return -floor(-arg)
def _eval_rewrite_as_frac(self, arg, **kwargs):
return arg + frac(-arg)
def _eval_is_positive(self):
return self.args[0].is_positive
def _eval_is_nonpositive(self):
return self.args[0].is_nonpositive
def __lt__(self, other):
other = S(other)
if self.args[0].is_real:
if other.is_integer:
return self.args[0] <= other - 1
if other.is_number and other.is_real:
return self.args[0] <= floor(other)
if self.args[0] == other and other.is_real:
return S.false
if other is S.Infinity and self.is_finite:
return S.true
return Lt(self, other, evaluate=False)
def __gt__(self, other):
other = S(other)
if self.args[0].is_real:
if other.is_integer:
return self.args[0] > other
if other.is_number and other.is_real:
return self.args[0] > floor(other)
if self.args[0] == other and other.is_real:
return S.false
if other is S.NegativeInfinity and self.is_finite:
return S.true
return Gt(self, other, evaluate=False)
def __ge__(self, other):
other = S(other)
if self.args[0].is_real:
if other.is_integer:
return self.args[0] > other - 1
if other.is_number and other.is_real:
return self.args[0] > floor(other)
if self.args[0] == other and other.is_real:
return S.true
if other is S.NegativeInfinity and self.is_finite:
return S.true
return Ge(self, other, evaluate=False)
def __le__(self, other):
other = S(other)
if self.args[0].is_real:
if other.is_integer:
return self.args[0] <= other
if other.is_number and other.is_real:
return self.args[0] <= floor(other)
if self.args[0] == other and other.is_real:
return S.false
if other is S.Infinity and self.is_finite:
return S.true
return Le(self, other, evaluate=False)
@dispatch(ceiling, Basic) # type:ignore
def _eval_is_eq(lhs, rhs): # noqa:F811
return is_eq(lhs.rewrite(floor), rhs) or is_eq(lhs.rewrite(frac),rhs)
class frac(Function):
r"""Represents the fractional part of x
For real numbers it is defined [1]_ as
.. math::
x - \left\lfloor{x}\right\rfloor
Examples
========
>>> from sympy import Symbol, frac, Rational, floor, I
>>> frac(Rational(4, 3))
1/3
>>> frac(-Rational(4, 3))
2/3
returns zero for integer arguments
>>> n = Symbol('n', integer=True)
>>> frac(n)
0
rewrite as floor
>>> x = Symbol('x')
>>> frac(x).rewrite(floor)
x - floor(x)
for complex arguments
>>> r = Symbol('r', real=True)
>>> t = Symbol('t', real=True)
>>> frac(t + I*r)
I*frac(r) + frac(t)
See Also
========
sympy.functions.elementary.integers.floor
sympy.functions.elementary.integers.ceiling
References
===========
.. [1] https://en.wikipedia.org/wiki/Fractional_part
.. [2] https://mathworld.wolfram.com/FractionalPart.html
"""
@classmethod
def eval(cls, arg):
from sympy.calculus.accumulationbounds import AccumBounds
def _eval(arg):
if arg in (S.Infinity, S.NegativeInfinity):
return AccumBounds(0, 1)
if arg.is_integer:
return S.Zero
if arg.is_number:
if arg is S.NaN:
return S.NaN
elif arg is S.ComplexInfinity:
return S.NaN
else:
return arg - floor(arg)
return cls(arg, evaluate=False)
real, imag = S.Zero, S.Zero
for t in Add.make_args(arg):
# Two checks are needed for complex arguments
# see issue-7649 for details
if t.is_imaginary or (S.ImaginaryUnit*t).is_real:
i = im(t)
if not i.has(S.ImaginaryUnit):
imag += i
else:
real += t
else:
real += t
real = _eval(real)
imag = _eval(imag)
return real + S.ImaginaryUnit*imag
def _eval_rewrite_as_floor(self, arg, **kwargs):
return arg - floor(arg)
def _eval_rewrite_as_ceiling(self, arg, **kwargs):
return arg + ceiling(-arg)
def _eval_is_finite(self):
return True
def _eval_is_real(self):
return self.args[0].is_extended_real
def _eval_is_imaginary(self):
return self.args[0].is_imaginary
def _eval_is_integer(self):
return self.args[0].is_integer
def _eval_is_zero(self):
return fuzzy_or([self.args[0].is_zero, self.args[0].is_integer])
def _eval_is_negative(self):
return False
def __ge__(self, other):
if self.is_extended_real:
other = _sympify(other)
# Check if other <= 0
if other.is_extended_nonpositive:
return S.true
# Check if other >= 1
res = self._value_one_or_more(other)
if res is not None:
return not(res)
return Ge(self, other, evaluate=False)
def __gt__(self, other):
if self.is_extended_real:
other = _sympify(other)
# Check if other < 0
res = self._value_one_or_more(other)
if res is not None:
return not(res)
# Check if other >= 1
if other.is_extended_negative:
return S.true
return Gt(self, other, evaluate=False)
def __le__(self, other):
if self.is_extended_real:
other = _sympify(other)
# Check if other < 0
if other.is_extended_negative:
return S.false
# Check if other >= 1
res = self._value_one_or_more(other)
if res is not None:
return res
return Le(self, other, evaluate=False)
def __lt__(self, other):
if self.is_extended_real:
other = _sympify(other)
# Check if other <= 0
if other.is_extended_nonpositive:
return S.false
# Check if other >= 1
res = self._value_one_or_more(other)
if res is not None:
return res
return Lt(self, other, evaluate=False)
def _value_one_or_more(self, other):
if other.is_extended_real:
if other.is_number:
res = other >= 1
if res and not isinstance(res, Relational):
return S.true
if other.is_integer and other.is_positive:
return S.true
def _eval_as_leading_term(self, x, logx=None, cdir=0):
from sympy.calculus.accumulationbounds import AccumBounds
arg = self.args[0]
arg0 = arg.subs(x, 0)
r = self.subs(x, 0)
if arg0.is_finite:
if r.is_zero:
ndir = arg.dir(x, cdir=cdir)
if ndir.is_negative:
return S.One
return (arg - arg0).as_leading_term(x, logx=logx, cdir=cdir)
else:
return r
elif arg0 in (S.ComplexInfinity, S.Infinity, S.NegativeInfinity):
return AccumBounds(0, 1)
return arg.as_leading_term(x, logx=logx, cdir=cdir)
def _eval_nseries(self, x, n, logx, cdir=0):
from sympy.series.order import Order
arg = self.args[0]
arg0 = arg.subs(x, 0)
r = self.subs(x, 0)
if arg0.is_infinite:
from sympy.calculus.accumulationbounds import AccumBounds
o = Order(1, (x, 0)) if n <= 0 else AccumBounds(0, 1) + Order(x**n, (x, 0))
return o
else:
res = (arg - arg0)._eval_nseries(x, n, logx=logx, cdir=cdir)
if r.is_zero:
ndir = arg.dir(x, cdir=cdir)
res += S.One if ndir.is_negative else S.Zero
else:
res += r
return res
@dispatch(frac, Basic) # type:ignore
def _eval_is_eq(lhs, rhs): # noqa:F811
if (lhs.rewrite(floor) == rhs) or \
(lhs.rewrite(ceiling) == rhs):
return True
# Check if other < 0
if rhs.is_extended_negative:
return False
# Check if other >= 1
res = lhs._value_one_or_more(rhs)
if res is not None:
return False
PK ]ZZZ �2�!m !m + sympy/functions/elementary/miscellaneous.pyfrom sympy.core import Function, S, sympify, NumberKind
from sympy.utilities.iterables import sift
from sympy.core.add import Add
from sympy.core.containers import Tuple
from sympy.core.operations import LatticeOp, ShortCircuit
from sympy.core.function import (Application, Lambda,
ArgumentIndexError)
from sympy.core.expr import Expr
from sympy.core.exprtools import factor_terms
from sympy.core.mod import Mod
from sympy.core.mul import Mul
from sympy.core.numbers import Rational
from sympy.core.power import Pow
from sympy.core.relational import Eq, Relational
from sympy.core.singleton import Singleton
from sympy.core.sorting import ordered
from sympy.core.symbol import Dummy
from sympy.core.rules import Transform
from sympy.core.logic import fuzzy_and, fuzzy_or, _torf
from sympy.core.traversal import walk
from sympy.core.numbers import Integer
from sympy.logic.boolalg import And, Or
def _minmax_as_Piecewise(op, *args):
# helper for Min/Max rewrite as Piecewise
from sympy.functions.elementary.piecewise import Piecewise
ec = []
for i, a in enumerate(args):
c = [Relational(a, args[j], op) for j in range(i + 1, len(args))]
ec.append((a, And(*c)))
return Piecewise(*ec)
class IdentityFunction(Lambda, metaclass=Singleton):
"""
The identity function
Examples
========
>>> from sympy import Id, Symbol
>>> x = Symbol('x')
>>> Id(x)
x
"""
_symbol = Dummy('x')
@property
def signature(self):
return Tuple(self._symbol)
@property
def expr(self):
return self._symbol
Id = S.IdentityFunction
###############################################################################
############################# ROOT and SQUARE ROOT FUNCTION ###################
###############################################################################
def sqrt(arg, evaluate=None):
"""Returns the principal square root.
Parameters
==========
evaluate : bool, optional
The parameter determines if the expression should be evaluated.
If ``None``, its value is taken from
``global_parameters.evaluate``.
Examples
========
>>> from sympy import sqrt, Symbol, S
>>> x = Symbol('x')
>>> sqrt(x)
sqrt(x)
>>> sqrt(x)**2
x
Note that sqrt(x**2) does not simplify to x.
>>> sqrt(x**2)
sqrt(x**2)
This is because the two are not equal to each other in general.
For example, consider x == -1:
>>> from sympy import Eq
>>> Eq(sqrt(x**2), x).subs(x, -1)
False
This is because sqrt computes the principal square root, so the square may
put the argument in a different branch. This identity does hold if x is
positive:
>>> y = Symbol('y', positive=True)
>>> sqrt(y**2)
y
You can force this simplification by using the powdenest() function with
the force option set to True:
>>> from sympy import powdenest
>>> sqrt(x**2)
sqrt(x**2)
>>> powdenest(sqrt(x**2), force=True)
x
To get both branches of the square root you can use the rootof function:
>>> from sympy import rootof
>>> [rootof(x**2-3,i) for i in (0,1)]
[-sqrt(3), sqrt(3)]
Although ``sqrt`` is printed, there is no ``sqrt`` function so looking for
``sqrt`` in an expression will fail:
>>> from sympy.utilities.misc import func_name
>>> func_name(sqrt(x))
'Pow'
>>> sqrt(x).has(sqrt)
False
To find ``sqrt`` look for ``Pow`` with an exponent of ``1/2``:
>>> (x + 1/sqrt(x)).find(lambda i: i.is_Pow and abs(i.exp) is S.Half)
{1/sqrt(x)}
See Also
========
sympy.polys.rootoftools.rootof, root, real_root
References
==========
.. [1] https://en.wikipedia.org/wiki/Square_root
.. [2] https://en.wikipedia.org/wiki/Principal_value
"""
# arg = sympify(arg) is handled by Pow
return Pow(arg, S.Half, evaluate=evaluate)
def cbrt(arg, evaluate=None):
"""Returns the principal cube root.
Parameters
==========
evaluate : bool, optional
The parameter determines if the expression should be evaluated.
If ``None``, its value is taken from
``global_parameters.evaluate``.
Examples
========
>>> from sympy import cbrt, Symbol
>>> x = Symbol('x')
>>> cbrt(x)
x**(1/3)
>>> cbrt(x)**3
x
Note that cbrt(x**3) does not simplify to x.
>>> cbrt(x**3)
(x**3)**(1/3)
This is because the two are not equal to each other in general.
For example, consider `x == -1`:
>>> from sympy import Eq
>>> Eq(cbrt(x**3), x).subs(x, -1)
False
This is because cbrt computes the principal cube root, this
identity does hold if `x` is positive:
>>> y = Symbol('y', positive=True)
>>> cbrt(y**3)
y
See Also
========
sympy.polys.rootoftools.rootof, root, real_root
References
==========
.. [1] https://en.wikipedia.org/wiki/Cube_root
.. [2] https://en.wikipedia.org/wiki/Principal_value
"""
return Pow(arg, Rational(1, 3), evaluate=evaluate)
def root(arg, n, k=0, evaluate=None):
r"""Returns the *k*-th *n*-th root of ``arg``.
Parameters
==========
k : int, optional
Should be an integer in $\{0, 1, ..., n-1\}$.
Defaults to the principal root if $0$.
evaluate : bool, optional
The parameter determines if the expression should be evaluated.
If ``None``, its value is taken from
``global_parameters.evaluate``.
Examples
========
>>> from sympy import root, Rational
>>> from sympy.abc import x, n
>>> root(x, 2)
sqrt(x)
>>> root(x, 3)
x**(1/3)
>>> root(x, n)
x**(1/n)
>>> root(x, -Rational(2, 3))
x**(-3/2)
To get the k-th n-th root, specify k:
>>> root(-2, 3, 2)
-(-1)**(2/3)*2**(1/3)
To get all n n-th roots you can use the rootof function.
The following examples show the roots of unity for n
equal 2, 3 and 4:
>>> from sympy import rootof
>>> [rootof(x**2 - 1, i) for i in range(2)]
[-1, 1]
>>> [rootof(x**3 - 1,i) for i in range(3)]
[1, -1/2 - sqrt(3)*I/2, -1/2 + sqrt(3)*I/2]
>>> [rootof(x**4 - 1,i) for i in range(4)]
[-1, 1, -I, I]
SymPy, like other symbolic algebra systems, returns the
complex root of negative numbers. This is the principal
root and differs from the text-book result that one might
be expecting. For example, the cube root of -8 does not
come back as -2:
>>> root(-8, 3)
2*(-1)**(1/3)
The real_root function can be used to either make the principal
result real (or simply to return the real root directly):
>>> from sympy import real_root
>>> real_root(_)
-2
>>> real_root(-32, 5)
-2
Alternatively, the n//2-th n-th root of a negative number can be
computed with root:
>>> root(-32, 5, 5//2)
-2
See Also
========
sympy.polys.rootoftools.rootof
sympy.core.intfunc.integer_nthroot
sqrt, real_root
References
==========
.. [1] https://en.wikipedia.org/wiki/Square_root
.. [2] https://en.wikipedia.org/wiki/Real_root
.. [3] https://en.wikipedia.org/wiki/Root_of_unity
.. [4] https://en.wikipedia.org/wiki/Principal_value
.. [5] https://mathworld.wolfram.com/CubeRoot.html
"""
n = sympify(n)
if k:
return Mul(Pow(arg, S.One/n, evaluate=evaluate), S.NegativeOne**(2*k/n), evaluate=evaluate)
return Pow(arg, 1/n, evaluate=evaluate)
def real_root(arg, n=None, evaluate=None):
r"""Return the real *n*'th-root of *arg* if possible.
Parameters
==========
n : int or None, optional
If *n* is ``None``, then all instances of
$(-n)^{1/\text{odd}}$ will be changed to $-n^{1/\text{odd}}$.
This will only create a real root of a principal root.
The presence of other factors may cause the result to not be
real.
evaluate : bool, optional
The parameter determines if the expression should be evaluated.
If ``None``, its value is taken from
``global_parameters.evaluate``.
Examples
========
>>> from sympy import root, real_root
>>> real_root(-8, 3)
-2
>>> root(-8, 3)
2*(-1)**(1/3)
>>> real_root(_)
-2
If one creates a non-principal root and applies real_root, the
result will not be real (so use with caution):
>>> root(-8, 3, 2)
-2*(-1)**(2/3)
>>> real_root(_)
-2*(-1)**(2/3)
See Also
========
sympy.polys.rootoftools.rootof
sympy.core.intfunc.integer_nthroot
root, sqrt
"""
from sympy.functions.elementary.complexes import Abs, im, sign
from sympy.functions.elementary.piecewise import Piecewise
if n is not None:
return Piecewise(
(root(arg, n, evaluate=evaluate), Or(Eq(n, S.One), Eq(n, S.NegativeOne))),
(Mul(sign(arg), root(Abs(arg), n, evaluate=evaluate), evaluate=evaluate),
And(Eq(im(arg), S.Zero), Eq(Mod(n, 2), S.One))),
(root(arg, n, evaluate=evaluate), True))
rv = sympify(arg)
n1pow = Transform(lambda x: -(-x.base)**x.exp,
lambda x:
x.is_Pow and
x.base.is_negative and
x.exp.is_Rational and
x.exp.p == 1 and x.exp.q % 2)
return rv.xreplace(n1pow)
###############################################################################
############################# MINIMUM and MAXIMUM #############################
###############################################################################
class MinMaxBase(Expr, LatticeOp):
def __new__(cls, *args, **assumptions):
from sympy.core.parameters import global_parameters
evaluate = assumptions.pop('evaluate', global_parameters.evaluate)
args = (sympify(arg) for arg in args)
# first standard filter, for cls.zero and cls.identity
# also reshape Max(a, Max(b, c)) to Max(a, b, c)
if evaluate:
try:
args = frozenset(cls._new_args_filter(args))
except ShortCircuit:
return cls.zero
# remove redundant args that are easily identified
args = cls._collapse_arguments(args, **assumptions)
# find local zeros
args = cls._find_localzeros(args, **assumptions)
args = frozenset(args)
if not args:
return cls.identity
if len(args) == 1:
return list(args).pop()
# base creation
obj = Expr.__new__(cls, *ordered(args), **assumptions)
obj._argset = args
return obj
@classmethod
def _collapse_arguments(cls, args, **assumptions):
"""Remove redundant args.
Examples
========
>>> from sympy import Min, Max
>>> from sympy.abc import a, b, c, d, e
Any arg in parent that appears in any
parent-like function in any of the flat args
of parent can be removed from that sub-arg:
>>> Min(a, Max(b, Min(a, c, d)))
Min(a, Max(b, Min(c, d)))
If the arg of parent appears in an opposite-than parent
function in any of the flat args of parent that function
can be replaced with the arg:
>>> Min(a, Max(b, Min(c, d, Max(a, e))))
Min(a, Max(b, Min(a, c, d)))
"""
if not args:
return args
args = list(ordered(args))
if cls == Min:
other = Max
else:
other = Min
# find global comparable max of Max and min of Min if a new
# value is being introduced in these args at position 0 of
# the ordered args
if args[0].is_number:
sifted = mins, maxs = [], []
for i in args:
for v in walk(i, Min, Max):
if v.args[0].is_comparable:
sifted[isinstance(v, Max)].append(v)
small = Min.identity
for i in mins:
v = i.args[0]
if v.is_number and (v < small) == True:
small = v
big = Max.identity
for i in maxs:
v = i.args[0]
if v.is_number and (v > big) == True:
big = v
# at the point when this function is called from __new__,
# there may be more than one numeric arg present since
# local zeros have not been handled yet, so look through
# more than the first arg
if cls == Min:
for arg in args:
if not arg.is_number:
break
if (arg < small) == True:
small = arg
elif cls == Max:
for arg in args:
if not arg.is_number:
break
if (arg > big) == True:
big = arg
T = None
if cls == Min:
if small != Min.identity:
other = Max
T = small
elif big != Max.identity:
other = Min
T = big
if T is not None:
# remove numerical redundancy
for i in range(len(args)):
a = args[i]
if isinstance(a, other):
a0 = a.args[0]
if ((a0 > T) if other == Max else (a0 < T)) == True:
args[i] = cls.identity
# remove redundant symbolic args
def do(ai, a):
if not isinstance(ai, (Min, Max)):
return ai
cond = a in ai.args
if not cond:
return ai.func(*[do(i, a) for i in ai.args],
evaluate=False)
if isinstance(ai, cls):
return ai.func(*[do(i, a) for i in ai.args if i != a],
evaluate=False)
return a
for i, a in enumerate(args):
args[i + 1:] = [do(ai, a) for ai in args[i + 1:]]
# factor out common elements as for
# Min(Max(x, y), Max(x, z)) -> Max(x, Min(y, z))
# and vice versa when swapping Min/Max -- do this only for the
# easy case where all functions contain something in common;
# trying to find some optimal subset of args to modify takes
# too long
def factor_minmax(args):
is_other = lambda arg: isinstance(arg, other)
other_args, remaining_args = sift(args, is_other, binary=True)
if not other_args:
return args
# Min(Max(x, y, z), Max(x, y, u, v)) -> {x,y}, ({z}, {u,v})
arg_sets = [set(arg.args) for arg in other_args]
common = set.intersection(*arg_sets)
if not common:
return args
new_other_args = list(common)
arg_sets_diff = [arg_set - common for arg_set in arg_sets]
# If any set is empty after removing common then all can be
# discarded e.g. Min(Max(a, b, c), Max(a, b)) -> Max(a, b)
if all(arg_sets_diff):
other_args_diff = [other(*s, evaluate=False) for s in arg_sets_diff]
new_other_args.append(cls(*other_args_diff, evaluate=False))
other_args_factored = other(*new_other_args, evaluate=False)
return remaining_args + [other_args_factored]
if len(args) > 1:
args = factor_minmax(args)
return args
@classmethod
def _new_args_filter(cls, arg_sequence):
"""
Generator filtering args.
first standard filter, for cls.zero and cls.identity.
Also reshape ``Max(a, Max(b, c))`` to ``Max(a, b, c)``,
and check arguments for comparability
"""
for arg in arg_sequence:
# pre-filter, checking comparability of arguments
if not isinstance(arg, Expr) or arg.is_extended_real is False or (
arg.is_number and
not arg.is_comparable):
raise ValueError("The argument '%s' is not comparable." % arg)
if arg == cls.zero:
raise ShortCircuit(arg)
elif arg == cls.identity:
continue
elif arg.func == cls:
yield from arg.args
else:
yield arg
@classmethod
def _find_localzeros(cls, values, **options):
"""
Sequentially allocate values to localzeros.
When a value is identified as being more extreme than another member it
replaces that member; if this is never true, then the value is simply
appended to the localzeros.
"""
localzeros = set()
for v in values:
is_newzero = True
localzeros_ = list(localzeros)
for z in localzeros_:
if id(v) == id(z):
is_newzero = False
else:
con = cls._is_connected(v, z)
if con:
is_newzero = False
if con is True or con == cls:
localzeros.remove(z)
localzeros.update([v])
if is_newzero:
localzeros.update([v])
return localzeros
@classmethod
def _is_connected(cls, x, y):
"""
Check if x and y are connected somehow.
"""
for i in range(2):
if x == y:
return True
t, f = Max, Min
for op in "><":
for j in range(2):
try:
if op == ">":
v = x >= y
else:
v = x <= y
except TypeError:
return False # non-real arg
if not v.is_Relational:
return t if v else f
t, f = f, t
x, y = y, x
x, y = y, x # run next pass with reversed order relative to start
# simplification can be expensive, so be conservative
# in what is attempted
x = factor_terms(x - y)
y = S.Zero
return False
def _eval_derivative(self, s):
# f(x).diff(s) -> x.diff(s) * f.fdiff(1)(s)
i = 0
l = []
for a in self.args:
i += 1
da = a.diff(s)
if da.is_zero:
continue
try:
df = self.fdiff(i)
except ArgumentIndexError:
df = Function.fdiff(self, i)
l.append(df * da)
return Add(*l)
def _eval_rewrite_as_Abs(self, *args, **kwargs):
from sympy.functions.elementary.complexes import Abs
s = (args[0] + self.func(*args[1:]))/2
d = abs(args[0] - self.func(*args[1:]))/2
return (s + d if isinstance(self, Max) else s - d).rewrite(Abs)
def evalf(self, n=15, **options):
return self.func(*[a.evalf(n, **options) for a in self.args])
def n(self, *args, **kwargs):
return self.evalf(*args, **kwargs)
_eval_is_algebraic = lambda s: _torf(i.is_algebraic for i in s.args)
_eval_is_antihermitian = lambda s: _torf(i.is_antihermitian for i in s.args)
_eval_is_commutative = lambda s: _torf(i.is_commutative for i in s.args)
_eval_is_complex = lambda s: _torf(i.is_complex for i in s.args)
_eval_is_composite = lambda s: _torf(i.is_composite for i in s.args)
_eval_is_even = lambda s: _torf(i.is_even for i in s.args)
_eval_is_finite = lambda s: _torf(i.is_finite for i in s.args)
_eval_is_hermitian = lambda s: _torf(i.is_hermitian for i in s.args)
_eval_is_imaginary = lambda s: _torf(i.is_imaginary for i in s.args)
_eval_is_infinite = lambda s: _torf(i.is_infinite for i in s.args)
_eval_is_integer = lambda s: _torf(i.is_integer for i in s.args)
_eval_is_irrational = lambda s: _torf(i.is_irrational for i in s.args)
_eval_is_negative = lambda s: _torf(i.is_negative for i in s.args)
_eval_is_noninteger = lambda s: _torf(i.is_noninteger for i in s.args)
_eval_is_nonnegative = lambda s: _torf(i.is_nonnegative for i in s.args)
_eval_is_nonpositive = lambda s: _torf(i.is_nonpositive for i in s.args)
_eval_is_nonzero = lambda s: _torf(i.is_nonzero for i in s.args)
_eval_is_odd = lambda s: _torf(i.is_odd for i in s.args)
_eval_is_polar = lambda s: _torf(i.is_polar for i in s.args)
_eval_is_positive = lambda s: _torf(i.is_positive for i in s.args)
_eval_is_prime = lambda s: _torf(i.is_prime for i in s.args)
_eval_is_rational = lambda s: _torf(i.is_rational for i in s.args)
_eval_is_real = lambda s: _torf(i.is_real for i in s.args)
_eval_is_extended_real = lambda s: _torf(i.is_extended_real for i in s.args)
_eval_is_transcendental = lambda s: _torf(i.is_transcendental for i in s.args)
_eval_is_zero = lambda s: _torf(i.is_zero for i in s.args)
class Max(MinMaxBase, Application):
r"""
Return, if possible, the maximum value of the list.
When number of arguments is equal one, then
return this argument.
When number of arguments is equal two, then
return, if possible, the value from (a, b) that is $\ge$ the other.
In common case, when the length of list greater than 2, the task
is more complicated. Return only the arguments, which are greater
than others, if it is possible to determine directional relation.
If is not possible to determine such a relation, return a partially
evaluated result.
Assumptions are used to make the decision too.
Also, only comparable arguments are permitted.
It is named ``Max`` and not ``max`` to avoid conflicts
with the built-in function ``max``.
Examples
========
>>> from sympy import Max, Symbol, oo
>>> from sympy.abc import x, y, z
>>> p = Symbol('p', positive=True)
>>> n = Symbol('n', negative=True)
>>> Max(x, -2)
Max(-2, x)
>>> Max(x, -2).subs(x, 3)
3
>>> Max(p, -2)
p
>>> Max(x, y)
Max(x, y)
>>> Max(x, y) == Max(y, x)
True
>>> Max(x, Max(y, z))
Max(x, y, z)
>>> Max(n, 8, p, 7, -oo)
Max(8, p)
>>> Max (1, x, oo)
oo
* Algorithm
The task can be considered as searching of supremums in the
directed complete partial orders [1]_.
The source values are sequentially allocated by the isolated subsets
in which supremums are searched and result as Max arguments.
If the resulted supremum is single, then it is returned.
The isolated subsets are the sets of values which are only the comparable
with each other in the current set. E.g. natural numbers are comparable with
each other, but not comparable with the `x` symbol. Another example: the
symbol `x` with negative assumption is comparable with a natural number.
Also there are "least" elements, which are comparable with all others,
and have a zero property (maximum or minimum for all elements).
For example, in case of $\infty$, the allocation operation is terminated
and only this value is returned.
Assumption:
- if $A > B > C$ then $A > C$
- if $A = B$ then $B$ can be removed
References
==========
.. [1] https://en.wikipedia.org/wiki/Directed_complete_partial_order
.. [2] https://en.wikipedia.org/wiki/Lattice_%28order%29
See Also
========
Min : find minimum values
"""
zero = S.Infinity
identity = S.NegativeInfinity
def fdiff( self, argindex ):
from sympy.functions.special.delta_functions import Heaviside
n = len(self.args)
if 0 < argindex and argindex <= n:
argindex -= 1
if n == 2:
return Heaviside(self.args[argindex] - self.args[1 - argindex])
newargs = tuple([self.args[i] for i in range(n) if i != argindex])
return Heaviside(self.args[argindex] - Max(*newargs))
else:
raise ArgumentIndexError(self, argindex)
def _eval_rewrite_as_Heaviside(self, *args, **kwargs):
from sympy.functions.special.delta_functions import Heaviside
return Add(*[j*Mul(*[Heaviside(j - i) for i in args if i!=j]) \
for j in args])
def _eval_rewrite_as_Piecewise(self, *args, **kwargs):
return _minmax_as_Piecewise('>=', *args)
def _eval_is_positive(self):
return fuzzy_or(a.is_positive for a in self.args)
def _eval_is_nonnegative(self):
return fuzzy_or(a.is_nonnegative for a in self.args)
def _eval_is_negative(self):
return fuzzy_and(a.is_negative for a in self.args)
class Min(MinMaxBase, Application):
"""
Return, if possible, the minimum value of the list.
It is named ``Min`` and not ``min`` to avoid conflicts
with the built-in function ``min``.
Examples
========
>>> from sympy import Min, Symbol, oo
>>> from sympy.abc import x, y
>>> p = Symbol('p', positive=True)
>>> n = Symbol('n', negative=True)
>>> Min(x, -2)
Min(-2, x)
>>> Min(x, -2).subs(x, 3)
-2
>>> Min(p, -3)
-3
>>> Min(x, y)
Min(x, y)
>>> Min(n, 8, p, -7, p, oo)
Min(-7, n)
See Also
========
Max : find maximum values
"""
zero = S.NegativeInfinity
identity = S.Infinity
def fdiff( self, argindex ):
from sympy.functions.special.delta_functions import Heaviside
n = len(self.args)
if 0 < argindex and argindex <= n:
argindex -= 1
if n == 2:
return Heaviside( self.args[1-argindex] - self.args[argindex] )
newargs = tuple([ self.args[i] for i in range(n) if i != argindex])
return Heaviside( Min(*newargs) - self.args[argindex] )
else:
raise ArgumentIndexError(self, argindex)
def _eval_rewrite_as_Heaviside(self, *args, **kwargs):
from sympy.functions.special.delta_functions import Heaviside
return Add(*[j*Mul(*[Heaviside(i-j) for i in args if i!=j]) \
for j in args])
def _eval_rewrite_as_Piecewise(self, *args, **kwargs):
return _minmax_as_Piecewise('<=', *args)
def _eval_is_positive(self):
return fuzzy_and(a.is_positive for a in self.args)
def _eval_is_nonnegative(self):
return fuzzy_and(a.is_nonnegative for a in self.args)
def _eval_is_negative(self):
return fuzzy_or(a.is_negative for a in self.args)
class Rem(Function):
"""Returns the remainder when ``p`` is divided by ``q`` where ``p`` is finite
and ``q`` is not equal to zero. The result, ``p - int(p/q)*q``, has the same sign
as the divisor.
Parameters
==========
p : Expr
Dividend.
q : Expr
Divisor.
Notes
=====
``Rem`` corresponds to the ``%`` operator in C.
Examples
========
>>> from sympy.abc import x, y
>>> from sympy import Rem
>>> Rem(x**3, y)
Rem(x**3, y)
>>> Rem(x**3, y).subs({x: -5, y: 3})
-2
See Also
========
Mod
"""
kind = NumberKind
@classmethod
def eval(cls, p, q):
"""Return the function remainder if both p, q are numbers and q is not
zero.
"""
if q.is_zero:
raise ZeroDivisionError("Division by zero")
if p is S.NaN or q is S.NaN or p.is_finite is False or q.is_finite is False:
return S.NaN
if p is S.Zero or p in (q, -q) or (p.is_integer and q == 1):
return S.Zero
if q.is_Number:
if p.is_Number:
return p - Integer(p/q)*q
PK ]ZZZ��3�� �� ' sympy/functions/elementary/piecewise.pyfrom sympy.core import S, Function, diff, Tuple, Dummy, Mul
from sympy.core.basic import Basic, as_Basic
from sympy.core.numbers import Rational, NumberSymbol, _illegal
from sympy.core.parameters import global_parameters
from sympy.core.relational import (Lt, Gt, Eq, Ne, Relational,
_canonical, _canonical_coeff)
from sympy.core.sorting import ordered
from sympy.functions.elementary.miscellaneous import Max, Min
from sympy.logic.boolalg import (And, Boolean, distribute_and_over_or, Not,
true, false, Or, ITE, simplify_logic, to_cnf, distribute_or_over_and)
from sympy.utilities.iterables import uniq, sift, common_prefix
from sympy.utilities.misc import filldedent, func_name
from itertools import product
Undefined = S.NaN # Piecewise()
class ExprCondPair(Tuple):
"""Represents an expression, condition pair."""
def __new__(cls, expr, cond):
expr = as_Basic(expr)
if cond == True:
return Tuple.__new__(cls, expr, true)
elif cond == False:
return Tuple.__new__(cls, expr, false)
elif isinstance(cond, Basic) and cond.has(Piecewise):
cond = piecewise_fold(cond)
if isinstance(cond, Piecewise):
cond = cond.rewrite(ITE)
if not isinstance(cond, Boolean):
raise TypeError(filldedent('''
Second argument must be a Boolean,
not `%s`''' % func_name(cond)))
return Tuple.__new__(cls, expr, cond)
@property
def expr(self):
"""
Returns the expression of this pair.
"""
return self.args[0]
@property
def cond(self):
"""
Returns the condition of this pair.
"""
return self.args[1]
@property
def is_commutative(self):
return self.expr.is_commutative
def __iter__(self):
yield self.expr
yield self.cond
def _eval_simplify(self, **kwargs):
return self.func(*[a.simplify(**kwargs) for a in self.args])
class Piecewise(Function):
"""
Represents a piecewise function.
Usage:
Piecewise( (expr,cond), (expr,cond), ... )
- Each argument is a 2-tuple defining an expression and condition
- The conds are evaluated in turn returning the first that is True.
If any of the evaluated conds are not explicitly False,
e.g. ``x < 1``, the function is returned in symbolic form.
- If the function is evaluated at a place where all conditions are False,
nan will be returned.
- Pairs where the cond is explicitly False, will be removed and no pair
appearing after a True condition will ever be retained. If a single
pair with a True condition remains, it will be returned, even when
evaluation is False.
Examples
========
>>> from sympy import Piecewise, log, piecewise_fold
>>> from sympy.abc import x, y
>>> f = x**2
>>> g = log(x)
>>> p = Piecewise((0, x < -1), (f, x <= 1), (g, True))
>>> p.subs(x,1)
1
>>> p.subs(x,5)
log(5)
Booleans can contain Piecewise elements:
>>> cond = (x < y).subs(x, Piecewise((2, x < 0), (3, True))); cond
Piecewise((2, x < 0), (3, True)) < y
The folded version of this results in a Piecewise whose
expressions are Booleans:
>>> folded_cond = piecewise_fold(cond); folded_cond
Piecewise((2 < y, x < 0), (3 < y, True))
When a Boolean containing Piecewise (like cond) or a Piecewise
with Boolean expressions (like folded_cond) is used as a condition,
it is converted to an equivalent :class:`~.ITE` object:
>>> Piecewise((1, folded_cond))
Piecewise((1, ITE(x < 0, y > 2, y > 3)))
When a condition is an ``ITE``, it will be converted to a simplified
Boolean expression:
>>> piecewise_fold(_)
Piecewise((1, ((x >= 0) | (y > 2)) & ((y > 3) | (x < 0))))
See Also
========
piecewise_fold
piecewise_exclusive
ITE
"""
nargs = None
is_Piecewise = True
def __new__(cls, *args, **options):
if len(args) == 0:
raise TypeError("At least one (expr, cond) pair expected.")
# (Try to) sympify args first
newargs = []
for ec in args:
# ec could be a ExprCondPair or a tuple
pair = ExprCondPair(*getattr(ec, 'args', ec))
cond = pair.cond
if cond is false:
continue
newargs.append(pair)
if cond is true:
break
eval = options.pop('evaluate', global_parameters.evaluate)
if eval:
r = cls.eval(*newargs)
if r is not None:
return r
elif len(newargs) == 1 and newargs[0].cond == True:
return newargs[0].expr
return Basic.__new__(cls, *newargs, **options)
@classmethod
def eval(cls, *_args):
"""Either return a modified version of the args or, if no
modifications were made, return None.
Modifications that are made here:
1. relationals are made canonical
2. any False conditions are dropped
3. any repeat of a previous condition is ignored
4. any args past one with a true condition are dropped
If there are no args left, nan will be returned.
If there is a single arg with a True condition, its
corresponding expression will be returned.
EXAMPLES
========
>>> from sympy import Piecewise
>>> from sympy.abc import x
>>> cond = -x < -1
>>> args = [(1, cond), (4, cond), (3, False), (2, True), (5, x < 1)]
>>> Piecewise(*args, evaluate=False)
Piecewise((1, -x < -1), (4, -x < -1), (2, True))
>>> Piecewise(*args)
Piecewise((1, x > 1), (2, True))
"""
if not _args:
return Undefined
if len(_args) == 1 and _args[0][-1] == True:
return _args[0][0]
newargs = _piecewise_collapse_arguments(_args)
# some conditions may have been redundant
missing = len(newargs) != len(_args)
# some conditions may have changed
same = all(a == b for a, b in zip(newargs, _args))
# if either change happened we return the expr with the
# updated args
if not newargs:
raise ValueError(filldedent('''
There are no conditions (or none that
are not trivially false) to define an
expression.'''))
if missing or not same:
return cls(*newargs)
def doit(self, **hints):
"""
Evaluate this piecewise function.
"""
newargs = []
for e, c in self.args:
if hints.get('deep', True):
if isinstance(e, Basic):
newe = e.doit(**hints)
if newe != self:
e = newe
if isinstance(c, Basic):
c = c.doit(**hints)
newargs.append((e, c))
return self.func(*newargs)
def _eval_simplify(self, **kwargs):
return piecewise_simplify(self, **kwargs)
def _eval_as_leading_term(self, x, logx=None, cdir=0):
for e, c in self.args:
if c == True or c.subs(x, 0) == True:
return e.as_leading_term(x)
def _eval_adjoint(self):
return self.func(*[(e.adjoint(), c) for e, c in self.args])
def _eval_conjugate(self):
return self.func(*[(e.conjugate(), c) for e, c in self.args])
def _eval_derivative(self, x):
return self.func(*[(diff(e, x), c) for e, c in self.args])
def _eval_evalf(self, prec):
return self.func(*[(e._evalf(prec), c) for e, c in self.args])
def _eval_is_meromorphic(self, x, a):
# Conditions often implicitly assume that the argument is real.
# Hence, there needs to be some check for as_set.
if not a.is_real:
return None
# Then, scan ExprCondPairs in the given order to find a piece that would contain a,
# possibly as a boundary point.
for e, c in self.args:
cond = c.subs(x, a)
if cond.is_Relational:
return None
if a in c.as_set().boundary:
return None
# Apply expression if a is an interior point of the domain of e.
if cond:
return e._eval_is_meromorphic(x, a)
def piecewise_integrate(self, x, **kwargs):
"""Return the Piecewise with each expression being
replaced with its antiderivative. To obtain a continuous
antiderivative, use the :func:`~.integrate` function or method.
Examples
========
>>> from sympy import Piecewise
>>> from sympy.abc import x
>>> p = Piecewise((0, x < 0), (1, x < 1), (2, True))
>>> p.piecewise_integrate(x)
Piecewise((0, x < 0), (x, x < 1), (2*x, True))
Note that this does not give a continuous function, e.g.
at x = 1 the 3rd condition applies and the antiderivative
there is 2*x so the value of the antiderivative is 2:
>>> anti = _
>>> anti.subs(x, 1)
2
The continuous derivative accounts for the integral *up to*
the point of interest, however:
>>> p.integrate(x)
Piecewise((0, x < 0), (x, x < 1), (2*x - 1, True))
>>> _.subs(x, 1)
1
See Also
========
Piecewise._eval_integral
"""
from sympy.integrals import integrate
return self.func(*[(integrate(e, x, **kwargs), c) for e, c in self.args])
def _handle_irel(self, x, handler):
"""Return either None (if the conditions of self depend only on x) else
a Piecewise expression whose expressions (handled by the handler that
was passed) are paired with the governing x-independent relationals,
e.g. Piecewise((A, a(x) & b(y)), (B, c(x) | c(y)) ->
Piecewise(
(handler(Piecewise((A, a(x) & True), (B, c(x) | True)), b(y) & c(y)),
(handler(Piecewise((A, a(x) & True), (B, c(x) | False)), b(y)),
(handler(Piecewise((A, a(x) & False), (B, c(x) | True)), c(y)),
(handler(Piecewise((A, a(x) & False), (B, c(x) | False)), True))
"""
# identify governing relationals
rel = self.atoms(Relational)
irel = list(ordered([r for r in rel if x not in r.free_symbols
and r not in (S.true, S.false)]))
if irel:
args = {}
exprinorder = []
for truth in product((1, 0), repeat=len(irel)):
reps = dict(zip(irel, truth))
# only store the true conditions since the false are implied
# when they appear lower in the Piecewise args
if 1 not in truth:
cond = None # flag this one so it doesn't get combined
else:
andargs = Tuple(*[i for i in reps if reps[i]])
free = list(andargs.free_symbols)
if len(free) == 1:
from sympy.solvers.inequalities import (
reduce_inequalities, _solve_inequality)
try:
t = reduce_inequalities(andargs, free[0])
# ValueError when there are potentially
# nonvanishing imaginary parts
except (ValueError, NotImplementedError):
# at least isolate free symbol on left
t = And(*[_solve_inequality(
a, free[0], linear=True)
for a in andargs])
else:
t = And(*andargs)
if t is S.false:
continue # an impossible combination
cond = t
expr = handler(self.xreplace(reps))
if isinstance(expr, self.func) and len(expr.args) == 1:
expr, econd = expr.args[0]
cond = And(econd, True if cond is None else cond)
# the ec pairs are being collected since all possibilities
# are being enumerated, but don't put the last one in since
# its expr might match a previous expression and it
# must appear last in the args
if cond is not None:
args.setdefault(expr, []).append(cond)
# but since we only store the true conditions we must maintain
# the order so that the expression with the most true values
# comes first
exprinorder.append(expr)
# convert collected conditions as args of Or
for k in args:
args[k] = Or(*args[k])
# take them in the order obtained
args = [(e, args[e]) for e in uniq(exprinorder)]
# add in the last arg
args.append((expr, True))
return Piecewise(*args)
def _eval_integral(self, x, _first=True, **kwargs):
"""Return the indefinite integral of the
Piecewise such that subsequent substitution of x with a
value will give the value of the integral (not including
the constant of integration) up to that point. To only
integrate the individual parts of Piecewise, use the
``piecewise_integrate`` method.
Examples
========
>>> from sympy import Piecewise
>>> from sympy.abc import x
>>> p = Piecewise((0, x < 0), (1, x < 1), (2, True))
>>> p.integrate(x)
Piecewise((0, x < 0), (x, x < 1), (2*x - 1, True))
>>> p.piecewise_integrate(x)
Piecewise((0, x < 0), (x, x < 1), (2*x, True))
See Also
========
Piecewise.piecewise_integrate
"""
from sympy.integrals.integrals import integrate
if _first:
def handler(ipw):
if isinstance(ipw, self.func):
return ipw._eval_integral(x, _first=False, **kwargs)
else:
return ipw.integrate(x, **kwargs)
irv = self._handle_irel(x, handler)
if irv is not None:
return irv
# handle a Piecewise from -oo to oo with and no x-independent relationals
# -----------------------------------------------------------------------
ok, abei = self._intervals(x)
if not ok:
from sympy.integrals.integrals import Integral
return Integral(self, x) # unevaluated
pieces = [(a, b) for a, b, _, _ in abei]
oo = S.Infinity
done = [(-oo, oo, -1)]
for k, p in enumerate(pieces):
if p == (-oo, oo):
# all undone intervals will get this key
for j, (a, b, i) in enumerate(done):
if i == -1:
done[j] = a, b, k
break # nothing else to consider
N = len(done) - 1
for j, (a, b, i) in enumerate(reversed(done)):
if i == -1:
j = N - j
done[j: j + 1] = _clip(p, (a, b), k)
done = [(a, b, i) for a, b, i in done if a != b]
# append an arg if there is a hole so a reference to
# argument -1 will give Undefined
if any(i == -1 for (a, b, i) in done):
abei.append((-oo, oo, Undefined, -1))
# return the sum of the intervals
args = []
sum = None
for a, b, i in done:
anti = integrate(abei[i][-2], x, **kwargs)
if sum is None:
sum = anti
else:
sum = sum.subs(x, a)
e = anti._eval_interval(x, a, x)
if sum.has(*_illegal) or e.has(*_illegal):
sum = anti
else:
sum += e
# see if we know whether b is contained in original
# condition
if b is S.Infinity:
cond = True
elif self.args[abei[i][-1]].cond.subs(x, b) == False:
cond = (x < b)
else:
cond = (x <= b)
args.append((sum, cond))
return Piecewise(*args)
def _eval_interval(self, sym, a, b, _first=True):
"""Evaluates the function along the sym in a given interval [a, b]"""
# FIXME: Currently complex intervals are not supported. A possible
# replacement algorithm, discussed in issue 5227, can be found in the
# following papers;
# http://portal.acm.org/citation.cfm?id=281649
# http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.70.4127&rep=rep1&type=pdf
if a is None or b is None:
# In this case, it is just simple substitution
return super()._eval_interval(sym, a, b)
else:
x, lo, hi = map(as_Basic, (sym, a, b))
if _first: # get only x-dependent relationals
def handler(ipw):
if isinstance(ipw, self.func):
return ipw._eval_interval(x, lo, hi, _first=None)
else:
return ipw._eval_interval(x, lo, hi)
irv = self._handle_irel(x, handler)
if irv is not None:
return irv
if (lo < hi) is S.false or (
lo is S.Infinity or hi is S.NegativeInfinity):
rv = self._eval_interval(x, hi, lo, _first=False)
if isinstance(rv, Piecewise):
rv = Piecewise(*[(-e, c) for e, c in rv.args])
else:
rv = -rv
return rv
if (lo < hi) is S.true or (
hi is S.Infinity or lo is S.NegativeInfinity):
pass
else:
_a = Dummy('lo')
_b = Dummy('hi')
a = lo if lo.is_comparable else _a
b = hi if hi.is_comparable else _b
pos = self._eval_interval(x, a, b, _first=False)
if a == _a and b == _b:
# it's purely symbolic so just swap lo and hi and
# change the sign to get the value for when lo > hi
neg, pos = (-pos.xreplace({_a: hi, _b: lo}),
pos.xreplace({_a: lo, _b: hi}))
else:
# at least one of the bounds was comparable, so allow
# _eval_interval to use that information when computing
# the interval with lo and hi reversed
neg, pos = (-self._eval_interval(x, hi, lo, _first=False),
pos.xreplace({_a: lo, _b: hi}))
# allow simplification based on ordering of lo and hi
p = Dummy('', positive=True)
if lo.is_Symbol:
pos = pos.xreplace({lo: hi - p}).xreplace({p: hi - lo})
neg = neg.xreplace({lo: hi + p}).xreplace({p: lo - hi})
elif hi.is_Symbol:
pos = pos.xreplace({hi: lo + p}).xreplace({p: hi - lo})
neg = neg.xreplace({hi: lo - p}).xreplace({p: lo - hi})
# evaluate limits that may have unevaluate Min/Max
touch = lambda _: _.replace(
lambda x: isinstance(x, (Min, Max)),
lambda x: x.func(*x.args))
neg = touch(neg)
pos = touch(pos)
# assemble return expression; make the first condition be Lt
# b/c then the first expression will look the same whether
# the lo or hi limit is symbolic
if a == _a: # the lower limit was symbolic
rv = Piecewise(
(pos,
lo < hi),
(neg,
True))
else:
rv = Piecewise(
(neg,
hi < lo),
(pos,
True))
if rv == Undefined:
raise ValueError("Can't integrate across undefined region.")
if any(isinstance(i, Piecewise) for i in (pos, neg)):
rv = piecewise_fold(rv)
return rv
# handle a Piecewise with lo <= hi and no x-independent relationals
# -----------------------------------------------------------------
ok, abei = self._intervals(x)
if not ok:
from sympy.integrals.integrals import Integral
# not being able to do the interval of f(x) can
# be stated as not being able to do the integral
# of f'(x) over the same range
return Integral(self.diff(x), (x, lo, hi)) # unevaluated
pieces = [(a, b) for a, b, _, _ in abei]
done = [(lo, hi, -1)]
oo = S.Infinity
for k, p in enumerate(pieces):
if p[:2] == (-oo, oo):
# all undone intervals will get this key
for j, (a, b, i) in enumerate(done):
if i == -1:
done[j] = a, b, k
break # nothing else to consider
N = len(done) - 1
for j, (a, b, i) in enumerate(reversed(done)):
if i == -1:
j = N - j
done[j: j + 1] = _clip(p, (a, b), k)
done = [(a, b, i) for a, b, i in done if a != b]
# return the sum of the intervals
sum = S.Zero
upto = None
for a, b, i in done:
if i == -1:
if upto is None:
return Undefined
# TODO simplify hi <= upto
return Piecewise((sum, hi <= upto), (Undefined, True))
sum += abei[i][-2]._eval_interval(x, a, b)
upto = b
return sum
def _intervals(self, sym, err_on_Eq=False):
r"""Return a bool and a message (when bool is False), else a
list of unique tuples, (a, b, e, i), where a and b
are the lower and upper bounds in which the expression e of
argument i in self is defined and $a < b$ (when involving
numbers) or $a \le b$ when involving symbols.
If there are any relationals not involving sym, or any
relational cannot be solved for sym, the bool will be False
a message be given as the second return value. The calling
routine should have removed such relationals before calling
this routine.
The evaluated conditions will be returned as ranges.
Discontinuous ranges will be returned separately with
identical expressions. The first condition that evaluates to
True will be returned as the last tuple with a, b = -oo, oo.
"""
from sympy.solvers.inequalities import _solve_inequality
assert isinstance(self, Piecewise)
def nonsymfail(cond):
return False, filldedent('''
A condition not involving
%s appeared: %s''' % (sym, cond))
def _solve_relational(r):
if sym not in r.free_symbols:
return nonsymfail(r)
try:
rv = _solve_inequality(r, sym)
except NotImplementedError:
return False, 'Unable to solve relational %s for %s.' % (r, sym)
if isinstance(rv, Relational):
free = rv.args[1].free_symbols
if rv.args[0] != sym or sym in free:
return False, 'Unable to solve relational %s for %s.' % (r, sym)
if rv.rel_op == '==':
# this equality has been affirmed to have the form
# Eq(sym, rhs) where rhs is sym-free; it represents
# a zero-width interval which will be ignored
# whether it is an isolated condition or contained
# within an And or an Or
rv = S.false
elif rv.rel_op == '!=':
try:
rv = Or(sym < rv.rhs, sym > rv.rhs)
except TypeError:
# e.g. x != I ==> all real x satisfy
rv = S.true
elif rv == (S.NegativeInfinity < sym) & (sym < S.Infinity):
rv = S.true
return True, rv
args = list(self.args)
# make self canonical wrt Relationals
keys = self.atoms(Relational)
reps = {}
for r in keys:
ok, s = _solve_relational(r)
if ok != True:
return False, ok
reps[r] = s
# process args individually so if any evaluate, their position
# in the original Piecewise will be known
args = [i.xreplace(reps) for i in self.args]
# precondition args
expr_cond = []
default = idefault = None
for i, (expr, cond) in enumerate(args):
if cond is S.false:
continue
if cond is S.true:
default = expr
idefault = i
break
if isinstance(cond, Eq):
# unanticipated condition, but it is here in case a
# replacement caused an Eq to appear
if err_on_Eq:
return False, 'encountered Eq condition: %s' % cond
continue # zero width interval
cond = to_cnf(cond)
if isinstance(cond, And):
cond = distribute_or_over_and(cond)
if isinstance(cond, Or):
expr_cond.extend(
[(i, expr, o) for o in cond.args
if not isinstance(o, Eq)])
elif cond is not S.false:
expr_cond.append((i, expr, cond))
elif cond is S.true:
default = expr
idefault = i
break
# determine intervals represented by conditions
int_expr = []
for iarg, expr, cond in expr_cond:
if isinstance(cond, And):
lower = S.NegativeInfinity
upper = S.Infinity
exclude = []
for cond2 in cond.args:
if not isinstance(cond2, Relational):
return False, 'expecting only Relationals'
if isinstance(cond2, Eq):
lower = upper # ignore
if err_on_Eq:
return False, 'encountered secondary Eq condition'
break
elif isinstance(cond2, Ne):
l, r = cond2.args
if l == sym:
exclude.append(r)
elif r == sym:
exclude.append(l)
else:
return nonsymfail(cond2)
continue
elif cond2.lts == sym:
upper = Min(cond2.gts, upper)
elif cond2.gts == sym:
lower = Max(cond2.lts, lower)
else:
return nonsymfail(cond2) # should never get here
if exclude:
exclude = list(ordered(exclude))
newcond = []
for i, e in enumerate(exclude):
if e < lower == True or e > upper == True:
continue
if not newcond:
newcond.append((None, lower)) # add a primer
newcond.append((newcond[-1][1], e))
newcond.append((newcond[-1][1], upper))
newcond.pop(0) # remove the primer
expr_cond.extend([(iarg, expr, And(i[0] < sym, sym < i[1])) for i in newcond])
continue
elif isinstance(cond, Relational) and cond.rel_op != '!=':
lower, upper = cond.lts, cond.gts # part 1: initialize with givens
if cond.lts == sym: # part 1a: expand the side ...
lower = S.NegativeInfinity # e.g. x <= 0 ---> -oo <= 0
elif cond.gts == sym: # part 1a: ... that can be expanded
upper = S.Infinity # e.g. x >= 0 ---> oo >= 0
else:
return nonsymfail(cond)
else:
return False, 'unrecognized condition: %s' % cond
lower, upper = lower, Max(lower, upper)
if err_on_Eq and lower == upper:
return False, 'encountered Eq condition'
if (lower >= upper) is not S.true:
int_expr.append((lower, upper, expr, iarg))
if default is not None:
int_expr.append(
(S.NegativeInfinity, S.Infinity, default, idefault))
return True, list(uniq(int_expr))
def _eval_nseries(self, x, n, logx, cdir=0):
args = [(ec.expr._eval_nseries(x, n, logx), ec.cond) for ec in self.args]
return self.func(*args)
def _eval_power(self, s):
return self.func(*[(e**s, c) for e, c in self.args])
def _eval_subs(self, old, new):
# this is strictly not necessary, but we can keep track
# of whether True or False conditions arise and be
# somewhat more efficient by avoiding other substitutions
# and avoiding invalid conditions that appear after a
# True condition
args = list(self.args)
args_exist = False
for i, (e, c) in enumerate(args):
c = c._subs(old, new)
if c != False:
args_exist = True
e = e._subs(old, new)
args[i] = (e, c)
if c == True:
break
if not args_exist:
args = ((Undefined, True),)
return self.func(*args)
def _eval_transpose(self):
return self.func(*[(e.transpose(), c) for e, c in self.args])
def _eval_template_is_attr(self, is_attr):
b = None
for expr, _ in self.args:
a = getattr(expr, is_attr)
if a is None:
return
if b is None:
b = a
elif b is not a:
return
return b
_eval_is_finite = lambda self: self._eval_template_is_attr(
'is_finite')
_eval_is_complex = lambda self: self._eval_template_is_attr('is_complex')
_eval_is_even = lambda self: self._eval_template_is_attr('is_even')
_eval_is_imaginary = lambda self: self._eval_template_is_attr(
'is_imaginary')
_eval_is_integer = lambda self: self._eval_template_is_attr('is_integer')
_eval_is_irrational = lambda self: self._eval_template_is_attr(
'is_irrational')
_eval_is_negative = lambda self: self._eval_template_is_attr('is_negative')
_eval_is_nonnegative = lambda self: self._eval_template_is_attr(
'is_nonnegative')
_eval_is_nonpositive = lambda self: self._eval_template_is_attr(
'is_nonpositive')
_eval_is_nonzero = lambda self: self._eval_template_is_attr(
'is_nonzero')
_eval_is_odd = lambda self: self._eval_template_is_attr('is_odd')
_eval_is_polar = lambda self: self._eval_template_is_attr('is_polar')
_eval_is_positive = lambda self: self._eval_template_is_attr('is_positive')
_eval_is_extended_real = lambda self: self._eval_template_is_attr(
'is_extended_real')
_eval_is_extended_positive = lambda self: self._eval_template_is_attr(
'is_extended_positive')
_eval_is_extended_negative = lambda self: self._eval_template_is_attr(
'is_extended_negative')
_eval_is_extended_nonzero = lambda self: self._eval_template_is_attr(
'is_extended_nonzero')
_eval_is_extended_nonpositive = lambda self: self._eval_template_is_attr(
'is_extended_nonpositive')
_eval_is_extended_nonnegative = lambda self: self._eval_template_is_attr(
'is_extended_nonnegative')
_eval_is_real = lambda self: self._eval_template_is_attr('is_real')
_eval_is_zero = lambda self: self._eval_template_is_attr(
'is_zero')
@classmethod
def __eval_cond(cls, cond):
"""Return the truth value of the condition."""
if cond == True:
return True
if isinstance(cond, Eq):
try:
diff = cond.lhs - cond.rhs
if diff.is_commutative:
return diff.is_zero
except TypeError:
pass
def as_expr_set_pairs(self, domain=None):
"""Return tuples for each argument of self that give
the expression and the interval in which it is valid
which is contained within the given domain.
If a condition cannot be converted to a set, an error
will be raised. The variable of the conditions is
assumed to be real; sets of real values are returned.
Examples
========
>>> from sympy import Piecewise, Interval
>>> from sympy.abc import x
>>> p = Piecewise(
... (1, x < 2),
... (2,(x > 0) & (x < 4)),
... (3, True))
>>> p.as_expr_set_pairs()
[(1, Interval.open(-oo, 2)),
(2, Interval.Ropen(2, 4)),
(3, Interval(4, oo))]
>>> p.as_expr_set_pairs(Interval(0, 3))
[(1, Interval.Ropen(0, 2)),
(2, Interval(2, 3))]
"""
if domain is None:
domain = S.Reals
exp_sets = []
U = domain
complex = not domain.is_subset(S.Reals)
cond_free = set()
for expr, cond in self.args:
cond_free |= cond.free_symbols
if len(cond_free) > 1:
raise NotImplementedError(filldedent('''
multivariate conditions are not handled.'''))
if complex:
for i in cond.atoms(Relational):
if not isinstance(i, (Eq, Ne)):
raise ValueError(filldedent('''
Inequalities in the complex domain are
not supported. Try the real domain by
setting domain=S.Reals'''))
cond_int = U.intersect(cond.as_set())
U = U - cond_int
if cond_int != S.EmptySet:
exp_sets.append((expr, cond_int))
return exp_sets
def _eval_rewrite_as_ITE(self, *args, **kwargs):
byfree = {}
args = list(args)
default = any(c == True for b, c in args)
for i, (b, c) in enumerate(args):
if not isinstance(b, Boolean) and b != True:
raise TypeError(filldedent('''
Expecting Boolean or bool but got `%s`
''' % func_name(b)))
if c == True:
break
# loop over independent conditions for this b
for c in c.args if isinstance(c, Or) else [c]:
free = c.free_symbols
x = free.pop()
try:
byfree[x] = byfree.setdefault(
x, S.EmptySet).union(c.as_set())
except NotImplementedError:
if not default:
raise NotImplementedError(filldedent('''
A method to determine whether a multivariate
conditional is consistent with a complete coverage
of all variables has not been implemented so the
rewrite is being stopped after encountering `%s`.
This error would not occur if a default expression
like `(foo, True)` were given.
''' % c))
if byfree[x] in (S.UniversalSet, S.Reals):
# collapse the ith condition to True and break
args[i] = list(args[i])
c = args[i][1] = True
break
if c == True:
break
if c != True:
raise ValueError(filldedent('''
Conditions must cover all reals or a final default
condition `(foo, True)` must be given.
'''))
last, _ = args[i] # ignore all past ith arg
for a, c in reversed(args[:i]):
last = ITE(c, a, last)
return _canonical(last)
def _eval_rewrite_as_KroneckerDelta(self, *args, **kwargs):
from sympy.functions.special.tensor_functions import KroneckerDelta
rules = {
And: [False, False],
Or: [True, True],
Not: [True, False],
Eq: [None, None],
Ne: [None, None]
}
class UnrecognizedCondition(Exception):
pass
def rewrite(cond):
if isinstance(cond, Eq):
return KroneckerDelta(*cond.args)
if isinstance(cond, Ne):
return 1 - KroneckerDelta(*cond.args)
cls, args = type(cond), cond.args
if cls not in rules:
raise UnrecognizedCondition(cls)
b1, b2 = rules[cls]
k = Mul(*[1 - rewrite(c) for c in args]) if b1 else Mul(*[rewrite(c) for c in args])
if b2:
return 1 - k
return k
conditions = []
true_value = None
for value, cond in args:
if type(cond) in rules:
conditions.append((value, cond))
elif cond is S.true:
if true_value is None:
true_value = value
else:
return
if true_value is not None:
result = true_value
for value, cond in conditions[::-1]:
try:
k = rewrite(cond)
result = k * value + (1 - k) * result
except UnrecognizedCondition:
return
return result
def piecewise_fold(expr, evaluate=True):
"""
Takes an expression containing a piecewise function and returns the
expression in piecewise form. In addition, any ITE conditions are
rewritten in negation normal form and simplified.
The final Piecewise is evaluated (default) but if the raw form
is desired, send ``evaluate=False``; if trivial evaluation is
desired, send ``evaluate=None`` and duplicate conditions and
processing of True and False will be handled.
Examples
========
>>> from sympy import Piecewise, piecewise_fold, S
>>> from sympy.abc import x
>>> p = Piecewise((x, x < 1), (1, S(1) <= x))
>>> piecewise_fold(x*p)
Piecewise((x**2, x < 1), (x, True))
See Also
========
Piecewise
piecewise_exclusive
"""
if not isinstance(expr, Basic) or not expr.has(Piecewise):
return expr
new_args = []
if isinstance(expr, (ExprCondPair, Piecewise)):
for e, c in expr.args:
if not isinstance(e, Piecewise):
e = piecewise_fold(e)
# we don't keep Piecewise in condition because
# it has to be checked to see that it's complete
# and we convert it to ITE at that time
assert not c.has(Piecewise) # pragma: no cover
if isinstance(c, ITE):
c = c.to_nnf()
c = simplify_logic(c, form='cnf')
if isinstance(e, Piecewise):
new_args.extend([(piecewise_fold(ei), And(ci, c))
for ei, ci in e.args])
else:
new_args.append((e, c))
else:
# Given
# P1 = Piecewise((e11, c1), (e12, c2), A)
# P2 = Piecewise((e21, c1), (e22, c2), B)
# ...
# the folding of f(P1, P2) is trivially
# Piecewise(
# (f(e11, e21), c1),
# (f(e12, e22), c2),
# (f(Piecewise(A), Piecewise(B)), True))
# Certain objects end up rewriting themselves as thus, so
# we do that grouping before the more generic folding.
# The following applies this idea when f = Add or f = Mul
# (and the expression is commutative).
if expr.is_Add or expr.is_Mul and expr.is_commutative:
p, args = sift(expr.args, lambda x: x.is_Piecewise, binary=True)
pc = sift(p, lambda x: tuple([c for e,c in x.args]))
for c in list(ordered(pc)):
if len(pc[c]) > 1:
pargs = [list(i.args) for i in pc[c]]
# the first one is the same; there may be more
com = common_prefix(*[
[i.cond for i in j] for j in pargs])
n = len(com)
collected = []
for i in range(n):
collected.append((
expr.func(*[ai[i].expr for ai in pargs]),
com[i]))
remains = []
for a in pargs:
if n == len(a): # no more args
continue
if a[n].cond == True: # no longer Piecewise
remains.append(a[n].expr)
else: # restore the remaining Piecewise
remains.append(
Piecewise(*a[n:], evaluate=False))
if remains:
collected.append((expr.func(*remains), True))
args.append(Piecewise(*collected, evaluate=False))
continue
args.extend(pc[c])
else:
args = expr.args
# fold
folded = list(map(piecewise_fold, args))
for ec in product(*[
(i.args if isinstance(i, Piecewise) else
[(i, true)]) for i in folded]):
e, c = zip(*ec)
new_args.append((expr.func(*e), And(*c)))
if evaluate is None:
# don't return duplicate conditions, otherwise don't evaluate
new_args = list(reversed([(e, c) for c, e in {
c: e for e, c in reversed(new_args)}.items()]))
rv = Piecewise(*new_args, evaluate=evaluate)
if evaluate is None and len(rv.args) == 1 and rv.args[0].cond == True:
return rv.args[0].expr
if any(s.expr.has(Piecewise) for p in rv.atoms(Piecewise) for s in p.args):
return piecewise_fold(rv)
return rv
def _clip(A, B, k):
"""Return interval B as intervals that are covered by A (keyed
to k) and all other intervals of B not covered by A keyed to -1.
The reference point of each interval is the rhs; if the lhs is
greater than the rhs then an interval of zero width interval will
result, e.g. (4, 1) is treated like (1, 1).
Examples
========
>>> from sympy.functions.elementary.piecewise import _clip
>>> from sympy import Tuple
>>> A = Tuple(1, 3)
>>> B = Tuple(2, 4)
>>> _clip(A, B, 0)
[(2, 3, 0), (3, 4, -1)]
Interpretation: interval portion (2, 3) of interval (2, 4) is
covered by interval (1, 3) and is keyed to 0 as requested;
interval (3, 4) was not covered by (1, 3) and is keyed to -1.
"""
a, b = B
c, d = A
c, d = Min(Max(c, a), b), Min(Max(d, a), b)
a, b = Min(a, b), b
p = []
if a != c:
p.append((a, c, -1))
else:
pass
if c != d:
p.append((c, d, k))
else:
pass
if b != d:
if d == c and p and p[-1][-1] == -1:
p[-1] = p[-1][0], b, -1
else:
p.append((d, b, -1))
else:
pass
return p
def piecewise_simplify_arguments(expr, **kwargs):
from sympy.simplify.simplify import simplify
# simplify conditions
f1 = expr.args[0].cond.free_symbols
args = None
if len(f1) == 1 and not expr.atoms(Eq):
x = f1.pop()
# this won't return intervals involving Eq
# and it won't handle symbols treated as
# booleans
ok, abe_ = expr._intervals(x, err_on_Eq=True)
def include(c, x, a):
"return True if c.subs(x, a) is True, else False"
try:
return c.subs(x, a) == True
except TypeError:
return False
if ok:
args = []
covered = S.EmptySet
from sympy.sets.sets import Interval
for a, b, e, i in abe_:
c = expr.args[i].cond
incl_a = include(c, x, a)
incl_b = include(c, x, b)
iv = Interval(a, b, not incl_a, not incl_b)
cset = iv - covered
if not cset:
continue
try:
a = cset.inf
except NotImplementedError:
pass # continue with the given `a`
else:
incl_a = include(c, x, a)
if incl_a and incl_b:
if a.is_infinite and b.is_infinite:
c = S.true
elif b.is_infinite:
c = (x > a) if a in covered else (x >= a)
elif a.is_infinite:
c = (x <= b)
elif a in covered:
c = And(a < x, x <= b)
else:
c = And(a <= x, x <= b)
elif incl_a:
if a.is_infinite:
c = (x < b)
elif a in covered:
c = And(a < x, x < b)
else:
c = And(a <= x, x < b)
elif incl_b:
if b.is_infinite:
c = (x > a)
else:
c = And(a < x, x <= b)
else:
if a in covered:
c = (x < b)
else:
c = And(a < x, x < b)
covered |= iv
if a is S.NegativeInfinity and incl_a:
covered |= {S.NegativeInfinity}
if b is S.Infinity and incl_b:
covered |= {S.Infinity}
args.append((e, c))
if not S.Reals.is_subset(covered):
args.append((Undefined, True))
if args is None:
args = list(expr.args)
for i in range(len(args)):
e, c = args[i]
if isinstance(c, Basic):
c = simplify(c, **kwargs)
args[i] = (e, c)
# simplify expressions
doit = kwargs.pop('doit', None)
for i in range(len(args)):
e, c = args[i]
if isinstance(e, Basic):
# Skip doit to avoid growth at every call for some integrals
# and sums, see sympy/sympy#17165
newe = simplify(e, doit=False, **kwargs)
if newe != e:
e = newe
args[i] = (e, c)
# restore kwargs flag
if doit is not None:
kwargs['doit'] = doit
return Piecewise(*args)
def _piecewise_collapse_arguments(_args):
newargs = [] # the unevaluated conditions
current_cond = set() # the conditions up to a given e, c pair
for expr, cond in _args:
cond = cond.replace(
lambda _: _.is_Relational, _canonical_coeff)
# Check here if expr is a Piecewise and collapse if one of
# the conds in expr matches cond. This allows the collapsing
# of Piecewise((Piecewise((x,x<0)),x<0)) to Piecewise((x,x<0)).
# This is important when using piecewise_fold to simplify
# multiple Piecewise instances having the same conds.
# Eventually, this code should be able to collapse Piecewise's
# having different intervals, but this will probably require
# using the new assumptions.
if isinstance(expr, Piecewise):
unmatching = []
for i, (e, c) in enumerate(expr.args):
if c in current_cond:
# this would already have triggered
continue
if c == cond:
if c != True:
# nothing past this condition will ever
# trigger and only those args before this
# that didn't match a previous condition
# could possibly trigger
if unmatching:
expr = Piecewise(*(
unmatching + [(e, c)]))
else:
expr = e
break
else:
unmatching.append((e, c))
# check for condition repeats
got = False
# -- if an And contains a condition that was
# already encountered, then the And will be
# False: if the previous condition was False
# then the And will be False and if the previous
# condition is True then then we wouldn't get to
# this point. In either case, we can skip this condition.
for i in ([cond] +
(list(cond.args) if isinstance(cond, And) else
[])):
if i in current_cond:
got = True
break
if got:
continue
# -- if not(c) is already in current_cond then c is
# a redundant condition in an And. This does not
# apply to Or, however: (e1, c), (e2, Or(~c, d))
# is not (e1, c), (e2, d) because if c and d are
# both False this would give no results when the
# true answer should be (e2, True)
if isinstance(cond, And):
nonredundant = []
for c in cond.args:
if isinstance(c, Relational):
if c.negated.canonical in current_cond:
continue
# if a strict inequality appears after
# a non-strict one, then the condition is
# redundant
if isinstance(c, (Lt, Gt)) and (
c.weak in current_cond):
cond = False
break
nonredundant.append(c)
else:
cond = cond.func(*nonredundant)
elif isinstance(cond, Relational):
if cond.negated.canonical in current_cond:
cond = S.true
current_cond.add(cond)
# collect successive e,c pairs when exprs or cond match
if newargs:
if newargs[-1].expr == expr:
orcond = Or(cond, newargs[-1].cond)
if isinstance(orcond, (And, Or)):
orcond = distribute_and_over_or(orcond)
newargs[-1] = ExprCondPair(expr, orcond)
continue
elif newargs[-1].cond == cond:
continue
newargs.append(ExprCondPair(expr, cond))
return newargs
_blessed = lambda e: getattr(e.lhs, '_diff_wrt', False) and (
getattr(e.rhs, '_diff_wrt', None) or
isinstance(e.rhs, (Rational, NumberSymbol)))
def piecewise_simplify(expr, **kwargs):
expr = piecewise_simplify_arguments(expr, **kwargs)
if not isinstance(expr, Piecewise):
return expr
args = list(expr.args)
args = _piecewise_simplify_eq_and(args)
args = _piecewise_simplify_equal_to_next_segment(args)
return Piecewise(*args)
def _piecewise_simplify_equal_to_next_segment(args):
"""
See if expressions valid for an Equal expression happens to evaluate
to the same function as in the next piecewise segment, see:
https://github.com/sympy/sympy/issues/8458
"""
prevexpr = None
for i, (expr, cond) in reversed(list(enumerate(args))):
if prevexpr is not None:
if isinstance(cond, And):
eqs, other = sift(cond.args,
lambda i: isinstance(i, Eq), binary=True)
elif isinstance(cond, Eq):
eqs, other = [cond], []
else:
eqs = other = []
_prevexpr = prevexpr
_expr = expr
if eqs and not other:
eqs = list(ordered(eqs))
for e in eqs:
# allow 2 args to collapse into 1 for any e
# otherwise limit simplification to only simple-arg
# Eq instances
if len(args) == 2 or _blessed(e):
_prevexpr = _prevexpr.subs(*e.args)
_expr = _expr.subs(*e.args)
# Did it evaluate to the same?
if _prevexpr == _expr:
# Set the expression for the Not equal section to the same
# as the next. These will be merged when creating the new
# Piecewise
args[i] = args[i].func(args[i + 1][0], cond)
else:
# Update the expression that we compare against
prevexpr = expr
else:
prevexpr = expr
return args
def _piecewise_simplify_eq_and(args):
"""
Try to simplify conditions and the expression for
equalities that are part of the condition, e.g.
Piecewise((n, And(Eq(n,0), Eq(n + m, 0))), (1, True))
-> Piecewise((0, And(Eq(n, 0), Eq(m, 0))), (1, True))
"""
for i, (expr, cond) in enumerate(args):
if isinstance(cond, And):
eqs, other = sift(cond.args,
lambda i: isinstance(i, Eq), binary=True)
elif isinstance(cond, Eq):
eqs, other = [cond], []
else:
eqs = other = []
if eqs:
eqs = list(ordered(eqs))
for j, e in enumerate(eqs):
# these blessed lhs objects behave like Symbols
# and the rhs are simple replacements for the "symbols"
if _blessed(e):
expr = expr.subs(*e.args)
eqs[j + 1:] = [ei.subs(*e.args) for ei in eqs[j + 1:]]
other = [ei.subs(*e.args) for ei in other]
cond = And(*(eqs + other))
args[i] = args[i].func(expr, cond)
return args
def piecewise_exclusive(expr, *, skip_nan=False, deep=True):
"""
Rewrite :class:`Piecewise` with mutually exclusive conditions.
Explanation
===========
SymPy represents the conditions of a :class:`Piecewise` in an
"if-elif"-fashion, allowing more than one condition to be simultaneously
True. The interpretation is that the first condition that is True is the
case that holds. While this is a useful representation computationally it
is not how a piecewise formula is typically shown in a mathematical text.
The :func:`piecewise_exclusive` function can be used to rewrite any
:class:`Piecewise` with more typical mutually exclusive conditions.
Note that further manipulation of the resulting :class:`Piecewise`, e.g.
simplifying it, will most likely make it non-exclusive. Hence, this is
primarily a function to be used in conjunction with printing the Piecewise
or if one would like to reorder the expression-condition pairs.
If it is not possible to determine that all possibilities are covered by
the different cases of the :class:`Piecewise` then a final
:class:`~sympy.core.numbers.NaN` case will be included explicitly. This
can be prevented by passing ``skip_nan=True``.
Examples
========
>>> from sympy import piecewise_exclusive, Symbol, Piecewise, S
>>> x = Symbol('x', real=True)
>>> p = Piecewise((0, x < 0), (S.Half, x <= 0), (1, True))
>>> piecewise_exclusive(p)
Piecewise((0, x < 0), (1/2, Eq(x, 0)), (1, x > 0))
>>> piecewise_exclusive(Piecewise((2, x > 1)))
Piecewise((2, x > 1), (nan, x <= 1))
>>> piecewise_exclusive(Piecewise((2, x > 1)), skip_nan=True)
Piecewise((2, x > 1))
Parameters
==========
expr: a SymPy expression.
Any :class:`Piecewise` in the expression will be rewritten.
skip_nan: ``bool`` (default ``False``)
If ``skip_nan`` is set to ``True`` then a final
:class:`~sympy.core.numbers.NaN` case will not be included.
deep: ``bool`` (default ``True``)
If ``deep`` is ``True`` then :func:`piecewise_exclusive` will rewrite
any :class:`Piecewise` subexpressions in ``expr`` rather than just
rewriting ``expr`` itself.
Returns
=======
An expression equivalent to ``expr`` but where all :class:`Piecewise` have
been rewritten with mutually exclusive conditions.
See Also
========
Piecewise
piecewise_fold
"""
def make_exclusive(*pwargs):
cumcond = false
newargs = []
# Handle the first n-1 cases
for expr_i, cond_i in pwargs[:-1]:
cancond = And(cond_i, Not(cumcond)).simplify()
cumcond = Or(cond_i, cumcond).simplify()
newargs.append((expr_i, cancond))
# For the nth case defer simplification of cumcond
expr_n, cond_n = pwargs[-1]
cancond_n = And(cond_n, Not(cumcond)).simplify()
newargs.append((expr_n, cancond_n))
if not skip_nan:
cumcond = Or(cond_n, cumcond).simplify()
if cumcond is not true:
newargs.append((Undefined, Not(cumcond).simplify()))
return Piecewise(*newargs, evaluate=False)
if deep:
return expr.replace(Piecewise, make_exclusive)
elif isinstance(expr, Piecewise):
return make_exclusive(*expr.args)
else:
return expr
PK ]ZZZ�e�ְ� �� + sympy/functions/elementary/trigonometric.pyfrom typing import Tuple as tTuple, Union as tUnion
from sympy.core.add import Add
from sympy.core.cache import cacheit
from sympy.core.expr import Expr
from sympy.core.function import Function, ArgumentIndexError, PoleError, expand_mul
from sympy.core.logic import fuzzy_not, fuzzy_or, FuzzyBool, fuzzy_and
from sympy.core.mod import Mod
from sympy.core.numbers import Rational, pi, Integer, Float, equal_valued
from sympy.core.relational import Ne, Eq
from sympy.core.singleton import S
from sympy.core.symbol import Symbol, Dummy
from sympy.core.sympify import sympify
from sympy.functions.combinatorial.factorials import factorial, RisingFactorial
from sympy.functions.combinatorial.numbers import bernoulli, euler
from sympy.functions.elementary.complexes import arg as arg_f, im, re
from sympy.functions.elementary.exponential import log, exp
from sympy.functions.elementary.integers import floor
from sympy.functions.elementary.miscellaneous import sqrt, Min, Max
from sympy.functions.elementary.piecewise import Piecewise
from sympy.functions.elementary._trigonometric_special import (
cos_table, ipartfrac, fermat_coords)
from sympy.logic.boolalg import And
from sympy.ntheory import factorint
from sympy.polys.specialpolys import symmetric_poly
from sympy.utilities.iterables import numbered_symbols
###############################################################################
########################## UTILITIES ##########################################
###############################################################################
def _imaginary_unit_as_coefficient(arg):
""" Helper to extract symbolic coefficient for imaginary unit """
if isinstance(arg, Float):
return None
else:
return arg.as_coefficient(S.ImaginaryUnit)
###############################################################################
########################## TRIGONOMETRIC FUNCTIONS ############################
###############################################################################
class TrigonometricFunction(Function):
"""Base class for trigonometric functions. """
unbranched = True
_singularities = (S.ComplexInfinity,)
def _eval_is_rational(self):
s = self.func(*self.args)
if s.func == self.func:
if s.args[0].is_rational and fuzzy_not(s.args[0].is_zero):
return False
else:
return s.is_rational
def _eval_is_algebraic(self):
s = self.func(*self.args)
if s.func == self.func:
if fuzzy_not(self.args[0].is_zero) and self.args[0].is_algebraic:
return False
pi_coeff = _pi_coeff(self.args[0])
if pi_coeff is not None and pi_coeff.is_rational:
return True
else:
return s.is_algebraic
def _eval_expand_complex(self, deep=True, **hints):
re_part, im_part = self.as_real_imag(deep=deep, **hints)
return re_part + im_part*S.ImaginaryUnit
def _as_real_imag(self, deep=True, **hints):
if self.args[0].is_extended_real:
if deep:
hints['complex'] = False
return (self.args[0].expand(deep, **hints), S.Zero)
else:
return (self.args[0], S.Zero)
if deep:
re, im = self.args[0].expand(deep, **hints).as_real_imag()
else:
re, im = self.args[0].as_real_imag()
return (re, im)
def _period(self, general_period, symbol=None):
f = expand_mul(self.args[0])
if symbol is None:
symbol = tuple(f.free_symbols)[0]
if not f.has(symbol):
return S.Zero
if f == symbol:
return general_period
if symbol in f.free_symbols:
if f.is_Mul:
g, h = f.as_independent(symbol)
if h == symbol:
return general_period/abs(g)
if f.is_Add:
a, h = f.as_independent(symbol)
g, h = h.as_independent(symbol, as_Add=False)
if h == symbol:
return general_period/abs(g)
raise NotImplementedError("Use the periodicity function instead.")
@cacheit
def _table2():
# If nested sqrt's are worse than un-evaluation
# you can require q to be in (1, 2, 3, 4, 6, 12)
# q <= 12, q=15, q=20, q=24, q=30, q=40, q=60, q=120 return
# expressions with 2 or fewer sqrt nestings.
return {
12: (3, 4),
20: (4, 5),
30: (5, 6),
15: (6, 10),
24: (6, 8),
40: (8, 10),
60: (20, 30),
120: (40, 60)
}
def _peeloff_pi(arg):
r"""
Split ARG into two parts, a "rest" and a multiple of $\pi$.
This assumes ARG to be an Add.
The multiple of $\pi$ returned in the second position is always a Rational.
Examples
========
>>> from sympy.functions.elementary.trigonometric import _peeloff_pi
>>> from sympy import pi
>>> from sympy.abc import x, y
>>> _peeloff_pi(x + pi/2)
(x, 1/2)
>>> _peeloff_pi(x + 2*pi/3 + pi*y)
(x + pi*y + pi/6, 1/2)
"""
pi_coeff = S.Zero
rest_terms = []
for a in Add.make_args(arg):
K = a.coeff(pi)
if K and K.is_rational:
pi_coeff += K
else:
rest_terms.append(a)
if pi_coeff is S.Zero:
return arg, S.Zero
m1 = (pi_coeff % S.Half)
m2 = pi_coeff - m1
if m2.is_integer or ((2*m2).is_integer and m2.is_even is False):
return Add(*(rest_terms + [m1*pi])), m2
return arg, S.Zero
def _pi_coeff(arg: Expr, cycles: int = 1) -> tUnion[Expr, None]:
r"""
When arg is a Number times $\pi$ (e.g. $3\pi/2$) then return the Number
normalized to be in the range $[0, 2]$, else `None`.
When an even multiple of $\pi$ is encountered, if it is multiplying
something with known parity then the multiple is returned as 0 otherwise
as 2.
Examples
========
>>> from sympy.functions.elementary.trigonometric import _pi_coeff
>>> from sympy import pi, Dummy
>>> from sympy.abc import x
>>> _pi_coeff(3*x*pi)
3*x
>>> _pi_coeff(11*pi/7)
11/7
>>> _pi_coeff(-11*pi/7)
3/7
>>> _pi_coeff(4*pi)
0
>>> _pi_coeff(5*pi)
1
>>> _pi_coeff(5.0*pi)
1
>>> _pi_coeff(5.5*pi)
3/2
>>> _pi_coeff(2 + pi)
>>> _pi_coeff(2*Dummy(integer=True)*pi)
2
>>> _pi_coeff(2*Dummy(even=True)*pi)
0
"""
if arg is pi:
return S.One
elif not arg:
return S.Zero
elif arg.is_Mul:
cx = arg.coeff(pi)
if cx:
c, x = cx.as_coeff_Mul() # pi is not included as coeff
if c.is_Float:
# recast exact binary fractions to Rationals
f = abs(c) % 1
if f != 0:
p = -int(round(log(f, 2).evalf()))
m = 2**p
cm = c*m
i = int(cm)
if equal_valued(i, cm):
c = Rational(i, m)
cx = c*x
else:
c = Rational(int(c))
cx = c*x
if x.is_integer:
c2 = c % 2
if c2 == 1:
return x
elif not c2:
if x.is_even is not None: # known parity
return S.Zero
return Integer(2)
else:
return c2*x
return cx
elif arg.is_zero:
return S.Zero
return None
class sin(TrigonometricFunction):
r"""
The sine function.
Returns the sine of x (measured in radians).
Explanation
===========
This function will evaluate automatically in the
case $x/\pi$ is some rational number [4]_. For example,
if $x$ is a multiple of $\pi$, $\pi/2$, $\pi/3$, $\pi/4$, and $\pi/6$.
Examples
========
>>> from sympy import sin, pi
>>> from sympy.abc import x
>>> sin(x**2).diff(x)
2*x*cos(x**2)
>>> sin(1).diff(x)
0
>>> sin(pi)
0
>>> sin(pi/2)
1
>>> sin(pi/6)
1/2
>>> sin(pi/12)
-sqrt(2)/4 + sqrt(6)/4
See Also
========
csc, cos, sec, tan, cot
asin, acsc, acos, asec, atan, acot, atan2
References
==========
.. [1] https://en.wikipedia.org/wiki/Trigonometric_functions
.. [2] https://dlmf.nist.gov/4.14
.. [3] https://functions.wolfram.com/ElementaryFunctions/Sin
.. [4] https://mathworld.wolfram.com/TrigonometryAngles.html
"""
def period(self, symbol=None):
return self._period(2*pi, symbol)
def fdiff(self, argindex=1):
if argindex == 1:
return cos(self.args[0])
else:
raise ArgumentIndexError(self, argindex)
@classmethod
def eval(cls, arg):
from sympy.calculus.accumulationbounds import AccumBounds
from sympy.sets.setexpr import SetExpr
if arg.is_Number:
if arg is S.NaN:
return S.NaN
elif arg.is_zero:
return S.Zero
elif arg in (S.Infinity, S.NegativeInfinity):
return AccumBounds(-1, 1)
if arg is S.ComplexInfinity:
return S.NaN
if isinstance(arg, AccumBounds):
from sympy.sets.sets import FiniteSet
min, max = arg.min, arg.max
d = floor(min/(2*pi))
if min is not S.NegativeInfinity:
min = min - d*2*pi
if max is not S.Infinity:
max = max - d*2*pi
if AccumBounds(min, max).intersection(FiniteSet(pi/2, pi*Rational(5, 2))) \
is not S.EmptySet and \
AccumBounds(min, max).intersection(FiniteSet(pi*Rational(3, 2),
pi*Rational(7, 2))) is not S.EmptySet:
return AccumBounds(-1, 1)
elif AccumBounds(min, max).intersection(FiniteSet(pi/2, pi*Rational(5, 2))) \
is not S.EmptySet:
return AccumBounds(Min(sin(min), sin(max)), 1)
elif AccumBounds(min, max).intersection(FiniteSet(pi*Rational(3, 2), pi*Rational(8, 2))) \
is not S.EmptySet:
return AccumBounds(-1, Max(sin(min), sin(max)))
else:
return AccumBounds(Min(sin(min), sin(max)),
Max(sin(min), sin(max)))
elif isinstance(arg, SetExpr):
return arg._eval_func(cls)
if arg.could_extract_minus_sign():
return -cls(-arg)
i_coeff = _imaginary_unit_as_coefficient(arg)
if i_coeff is not None:
from sympy.functions.elementary.hyperbolic import sinh
return S.ImaginaryUnit*sinh(i_coeff)
pi_coeff = _pi_coeff(arg)
if pi_coeff is not None:
if pi_coeff.is_integer:
return S.Zero
if (2*pi_coeff).is_integer:
# is_even-case handled above as then pi_coeff.is_integer,
# so check if known to be not even
if pi_coeff.is_even is False:
return S.NegativeOne**(pi_coeff - S.Half)
if not pi_coeff.is_Rational:
narg = pi_coeff*pi
if narg != arg:
return cls(narg)
return None
# https://github.com/sympy/sympy/issues/6048
# transform a sine to a cosine, to avoid redundant code
if pi_coeff.is_Rational:
x = pi_coeff % 2
if x > 1:
return -cls((x % 1)*pi)
if 2*x > 1:
return cls((1 - x)*pi)
narg = ((pi_coeff + Rational(3, 2)) % 2)*pi
result = cos(narg)
if not isinstance(result, cos):
return result
if pi_coeff*pi != arg:
return cls(pi_coeff*pi)
return None
if arg.is_Add:
x, m = _peeloff_pi(arg)
if m:
m = m*pi
return sin(m)*cos(x) + cos(m)*sin(x)
if arg.is_zero:
return S.Zero
if isinstance(arg, asin):
return arg.args[0]
if isinstance(arg, atan):
x = arg.args[0]
return x/sqrt(1 + x**2)
if isinstance(arg, atan2):
y, x = arg.args
return y/sqrt(x**2 + y**2)
if isinstance(arg, acos):
x = arg.args[0]
return sqrt(1 - x**2)
if isinstance(arg, acot):
x = arg.args[0]
return 1/(sqrt(1 + 1/x**2)*x)
if isinstance(arg, acsc):
x = arg.args[0]
return 1/x
if isinstance(arg, asec):
x = arg.args[0]
return sqrt(1 - 1/x**2)
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
if n < 0 or n % 2 == 0:
return S.Zero
else:
x = sympify(x)
if len(previous_terms) > 2:
p = previous_terms[-2]
return -p*x**2/(n*(n - 1))
else:
return S.NegativeOne**(n//2)*x**n/factorial(n)
def _eval_nseries(self, x, n, logx, cdir=0):
arg = self.args[0]
if logx is not None:
arg = arg.subs(log(x), logx)
if arg.subs(x, 0).has(S.NaN, S.ComplexInfinity):
raise PoleError("Cannot expand %s around 0" % (self))
return Function._eval_nseries(self, x, n=n, logx=logx, cdir=cdir)
def _eval_rewrite_as_exp(self, arg, **kwargs):
from sympy.functions.elementary.hyperbolic import HyperbolicFunction
I = S.ImaginaryUnit
if isinstance(arg, (TrigonometricFunction, HyperbolicFunction)):
arg = arg.func(arg.args[0]).rewrite(exp)
return (exp(arg*I) - exp(-arg*I))/(2*I)
def _eval_rewrite_as_Pow(self, arg, **kwargs):
if isinstance(arg, log):
I = S.ImaginaryUnit
x = arg.args[0]
return I*x**-I/2 - I*x**I /2
def _eval_rewrite_as_cos(self, arg, **kwargs):
return cos(arg - pi/2, evaluate=False)
def _eval_rewrite_as_tan(self, arg, **kwargs):
tan_half = tan(S.Half*arg)
return 2*tan_half/(1 + tan_half**2)
def _eval_rewrite_as_sincos(self, arg, **kwargs):
return sin(arg)*cos(arg)/cos(arg)
def _eval_rewrite_as_cot(self, arg, **kwargs):
cot_half = cot(S.Half*arg)
return Piecewise((0, And(Eq(im(arg), 0), Eq(Mod(arg, pi), 0))),
(2*cot_half/(1 + cot_half**2), True))
def _eval_rewrite_as_pow(self, arg, **kwargs):
return self.rewrite(cos, **kwargs).rewrite(pow, **kwargs)
def _eval_rewrite_as_sqrt(self, arg, **kwargs):
return self.rewrite(cos, **kwargs).rewrite(sqrt, **kwargs)
def _eval_rewrite_as_csc(self, arg, **kwargs):
return 1/csc(arg)
def _eval_rewrite_as_sec(self, arg, **kwargs):
return 1/sec(arg - pi/2, evaluate=False)
def _eval_rewrite_as_sinc(self, arg, **kwargs):
return arg*sinc(arg)
def _eval_rewrite_as_besselj(self, arg, **kwargs):
from sympy.functions.special.bessel import besselj
return sqrt(pi*arg/2)*besselj(S.Half, arg)
def _eval_conjugate(self):
return self.func(self.args[0].conjugate())
def as_real_imag(self, deep=True, **hints):
from sympy.functions.elementary.hyperbolic import cosh, sinh
re, im = self._as_real_imag(deep=deep, **hints)
return (sin(re)*cosh(im), cos(re)*sinh(im))
def _eval_expand_trig(self, **hints):
from sympy.functions.special.polynomials import chebyshevt, chebyshevu
arg = self.args[0]
x = None
if arg.is_Add: # TODO, implement more if deep stuff here
# TODO: Do this more efficiently for more than two terms
x, y = arg.as_two_terms()
sx = sin(x, evaluate=False)._eval_expand_trig()
sy = sin(y, evaluate=False)._eval_expand_trig()
cx = cos(x, evaluate=False)._eval_expand_trig()
cy = cos(y, evaluate=False)._eval_expand_trig()
return sx*cy + sy*cx
elif arg.is_Mul:
n, x = arg.as_coeff_Mul(rational=True)
if n.is_Integer: # n will be positive because of .eval
# canonicalization
# See https://mathworld.wolfram.com/Multiple-AngleFormulas.html
if n.is_odd:
return S.NegativeOne**((n - 1)/2)*chebyshevt(n, sin(x))
else:
return expand_mul(S.NegativeOne**(n/2 - 1)*cos(x)*
chebyshevu(n - 1, sin(x)), deep=False)
return sin(arg)
def _eval_as_leading_term(self, x, logx=None, cdir=0):
from sympy.calculus.accumulationbounds import AccumBounds
arg = self.args[0]
x0 = arg.subs(x, 0).cancel()
n = x0/pi
if n.is_integer:
lt = (arg - n*pi).as_leading_term(x)
return (S.NegativeOne**n)*lt
if x0 is S.ComplexInfinity:
x0 = arg.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
if x0 in [S.Infinity, S.NegativeInfinity]:
return AccumBounds(-1, 1)
return self.func(x0) if x0.is_finite else self
def _eval_is_extended_real(self):
if self.args[0].is_extended_real:
return True
def _eval_is_finite(self):
arg = self.args[0]
if arg.is_extended_real:
return True
def _eval_is_zero(self):
rest, pi_mult = _peeloff_pi(self.args[0])
if rest.is_zero:
return pi_mult.is_integer
def _eval_is_complex(self):
if self.args[0].is_extended_real \
or self.args[0].is_complex:
return True
class cos(TrigonometricFunction):
"""
The cosine function.
Returns the cosine of x (measured in radians).
Explanation
===========
See :func:`sin` for notes about automatic evaluation.
Examples
========
>>> from sympy import cos, pi
>>> from sympy.abc import x
>>> cos(x**2).diff(x)
-2*x*sin(x**2)
>>> cos(1).diff(x)
0
>>> cos(pi)
-1
>>> cos(pi/2)
0
>>> cos(2*pi/3)
-1/2
>>> cos(pi/12)
sqrt(2)/4 + sqrt(6)/4
See Also
========
sin, csc, sec, tan, cot
asin, acsc, acos, asec, atan, acot, atan2
References
==========
.. [1] https://en.wikipedia.org/wiki/Trigonometric_functions
.. [2] https://dlmf.nist.gov/4.14
.. [3] https://functions.wolfram.com/ElementaryFunctions/Cos
"""
def period(self, symbol=None):
return self._period(2*pi, symbol)
def fdiff(self, argindex=1):
if argindex == 1:
return -sin(self.args[0])
else:
raise ArgumentIndexError(self, argindex)
@classmethod
def eval(cls, arg):
from sympy.functions.special.polynomials import chebyshevt
from sympy.calculus.accumulationbounds import AccumBounds
from sympy.sets.setexpr import SetExpr
if arg.is_Number:
if arg is S.NaN:
return S.NaN
elif arg.is_zero:
return S.One
elif arg in (S.Infinity, S.NegativeInfinity):
# In this case it is better to return AccumBounds(-1, 1)
# rather than returning S.NaN, since AccumBounds(-1, 1)
# preserves the information that sin(oo) is between
# -1 and 1, where S.NaN does not do that.
return AccumBounds(-1, 1)
if arg is S.ComplexInfinity:
return S.NaN
if isinstance(arg, AccumBounds):
return sin(arg + pi/2)
elif isinstance(arg, SetExpr):
return arg._eval_func(cls)
if arg.is_extended_real and arg.is_finite is False:
return AccumBounds(-1, 1)
if arg.could_extract_minus_sign():
return cls(-arg)
i_coeff = _imaginary_unit_as_coefficient(arg)
if i_coeff is not None:
from sympy.functions.elementary.hyperbolic import cosh
return cosh(i_coeff)
pi_coeff = _pi_coeff(arg)
if pi_coeff is not None:
if pi_coeff.is_integer:
return (S.NegativeOne)**pi_coeff
if (2*pi_coeff).is_integer:
# is_even-case handled above as then pi_coeff.is_integer,
# so check if known to be not even
if pi_coeff.is_even is False:
return S.Zero
if not pi_coeff.is_Rational:
narg = pi_coeff*pi
if narg != arg:
return cls(narg)
return None
# cosine formula #####################
# https://github.com/sympy/sympy/issues/6048
# explicit calculations are performed for
# cos(k pi/n) for n = 8,10,12,15,20,24,30,40,60,120
# Some other exact values like cos(k pi/240) can be
# calculated using a partial-fraction decomposition
# by calling cos( X ).rewrite(sqrt)
if pi_coeff.is_Rational:
q = pi_coeff.q
p = pi_coeff.p % (2*q)
if p > q:
narg = (pi_coeff - 1)*pi
return -cls(narg)
if 2*p > q:
narg = (1 - pi_coeff)*pi
return -cls(narg)
# If nested sqrt's are worse than un-evaluation
# you can require q to be in (1, 2, 3, 4, 6, 12)
# q <= 12, q=15, q=20, q=24, q=30, q=40, q=60, q=120 return
# expressions with 2 or fewer sqrt nestings.
table2 = _table2()
if q in table2:
a, b = table2[q]
a, b = p*pi/a, p*pi/b
nvala, nvalb = cls(a), cls(b)
if None in (nvala, nvalb):
return None
return nvala*nvalb + cls(pi/2 - a)*cls(pi/2 - b)
if q > 12:
return None
cst_table_some = {
3: S.Half,
5: (sqrt(5) + 1) / 4,
}
if q in cst_table_some:
cts = cst_table_some[pi_coeff.q]
return chebyshevt(pi_coeff.p, cts).expand()
if 0 == q % 2:
narg = (pi_coeff*2)*pi
nval = cls(narg)
if None == nval:
return None
x = (2*pi_coeff + 1)/2
sign_cos = (-1)**((-1 if x < 0 else 1)*int(abs(x)))
return sign_cos*sqrt( (1 + nval)/2 )
return None
if arg.is_Add:
x, m = _peeloff_pi(arg)
if m:
m = m*pi
return cos(m)*cos(x) - sin(m)*sin(x)
if arg.is_zero:
return S.One
if isinstance(arg, acos):
return arg.args[0]
if isinstance(arg, atan):
x = arg.args[0]
return 1/sqrt(1 + x**2)
if isinstance(arg, atan2):
y, x = arg.args
return x/sqrt(x**2 + y**2)
if isinstance(arg, asin):
x = arg.args[0]
return sqrt(1 - x ** 2)
if isinstance(arg, acot):
x = arg.args[0]
return 1/sqrt(1 + 1/x**2)
if isinstance(arg, acsc):
x = arg.args[0]
return sqrt(1 - 1/x**2)
if isinstance(arg, asec):
x = arg.args[0]
return 1/x
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
if n < 0 or n % 2 == 1:
return S.Zero
else:
x = sympify(x)
if len(previous_terms) > 2:
p = previous_terms[-2]
return -p*x**2/(n*(n - 1))
else:
return S.NegativeOne**(n//2)*x**n/factorial(n)
def _eval_nseries(self, x, n, logx, cdir=0):
arg = self.args[0]
if logx is not None:
arg = arg.subs(log(x), logx)
if arg.subs(x, 0).has(S.NaN, S.ComplexInfinity):
raise PoleError("Cannot expand %s around 0" % (self))
return Function._eval_nseries(self, x, n=n, logx=logx, cdir=cdir)
def _eval_rewrite_as_exp(self, arg, **kwargs):
I = S.ImaginaryUnit
from sympy.functions.elementary.hyperbolic import HyperbolicFunction
if isinstance(arg, (TrigonometricFunction, HyperbolicFunction)):
arg = arg.func(arg.args[0]).rewrite(exp, **kwargs)
return (exp(arg*I) + exp(-arg*I))/2
def _eval_rewrite_as_Pow(self, arg, **kwargs):
if isinstance(arg, log):
I = S.ImaginaryUnit
x = arg.args[0]
return x**I/2 + x**-I/2
def _eval_rewrite_as_sin(self, arg, **kwargs):
return sin(arg + pi/2, evaluate=False)
def _eval_rewrite_as_tan(self, arg, **kwargs):
tan_half = tan(S.Half*arg)**2
return (1 - tan_half)/(1 + tan_half)
def _eval_rewrite_as_sincos(self, arg, **kwargs):
return sin(arg)*cos(arg)/sin(arg)
def _eval_rewrite_as_cot(self, arg, **kwargs):
cot_half = cot(S.Half*arg)**2
return Piecewise((1, And(Eq(im(arg), 0), Eq(Mod(arg, 2*pi), 0))),
((cot_half - 1)/(cot_half + 1), True))
def _eval_rewrite_as_pow(self, arg, **kwargs):
return self._eval_rewrite_as_sqrt(arg, **kwargs)
def _eval_rewrite_as_sqrt(self, arg: Expr, **kwargs):
from sympy.functions.special.polynomials import chebyshevt
pi_coeff = _pi_coeff(arg)
if pi_coeff is None:
return None
if isinstance(pi_coeff, Integer):
return None
if not isinstance(pi_coeff, Rational):
return None
cst_table_some = cos_table()
if pi_coeff.q in cst_table_some:
rv = chebyshevt(pi_coeff.p, cst_table_some[pi_coeff.q]())
if pi_coeff.q < 257:
rv = rv.expand()
return rv
if not pi_coeff.q % 2: # recursively remove factors of 2
pico2 = pi_coeff * 2
nval = cos(pico2 * pi).rewrite(sqrt, **kwargs)
x = (pico2 + 1) / 2
sign_cos = -1 if int(x) % 2 else 1
return sign_cos * sqrt((1 + nval) / 2)
FC = fermat_coords(pi_coeff.q)
if FC:
denoms = FC
else:
denoms = [b**e for b, e in factorint(pi_coeff.q).items()]
apart = ipartfrac(*denoms)
decomp = (pi_coeff.p * Rational(n, d) for n, d in zip(apart, denoms))
X = [(x[1], x[0]*pi) for x in zip(decomp, numbered_symbols('z'))]
pcls = cos(sum(x[0] for x in X))._eval_expand_trig().subs(X)
if not FC or len(FC) == 1:
return pcls
return pcls.rewrite(sqrt, **kwargs)
def _eval_rewrite_as_sec(self, arg, **kwargs):
return 1/sec(arg)
def _eval_rewrite_as_csc(self, arg, **kwargs):
return 1/sec(arg).rewrite(csc, **kwargs)
def _eval_rewrite_as_besselj(self, arg, **kwargs):
from sympy.functions.special.bessel import besselj
return Piecewise(
(sqrt(pi*arg/2)*besselj(-S.Half, arg), Ne(arg, 0)),
(1, True)
)
def _eval_conjugate(self):
return self.func(self.args[0].conjugate())
def as_real_imag(self, deep=True, **hints):
from sympy.functions.elementary.hyperbolic import cosh, sinh
re, im = self._as_real_imag(deep=deep, **hints)
return (cos(re)*cosh(im), -sin(re)*sinh(im))
def _eval_expand_trig(self, **hints):
from sympy.functions.special.polynomials import chebyshevt
arg = self.args[0]
x = None
if arg.is_Add: # TODO: Do this more efficiently for more than two terms
x, y = arg.as_two_terms()
sx = sin(x, evaluate=False)._eval_expand_trig()
sy = sin(y, evaluate=False)._eval_expand_trig()
cx = cos(x, evaluate=False)._eval_expand_trig()
cy = cos(y, evaluate=False)._eval_expand_trig()
return cx*cy - sx*sy
elif arg.is_Mul:
coeff, terms = arg.as_coeff_Mul(rational=True)
if coeff.is_Integer:
return chebyshevt(coeff, cos(terms))
return cos(arg)
def _eval_as_leading_term(self, x, logx=None, cdir=0):
from sympy.calculus.accumulationbounds import AccumBounds
arg = self.args[0]
x0 = arg.subs(x, 0).cancel()
n = (x0 + pi/2)/pi
if n.is_integer:
lt = (arg - n*pi + pi/2).as_leading_term(x)
return (S.NegativeOne**n)*lt
if x0 is S.ComplexInfinity:
x0 = arg.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
if x0 in [S.Infinity, S.NegativeInfinity]:
return AccumBounds(-1, 1)
return self.func(x0) if x0.is_finite else self
def _eval_is_extended_real(self):
if self.args[0].is_extended_real:
return True
def _eval_is_finite(self):
arg = self.args[0]
if arg.is_extended_real:
return True
def _eval_is_complex(self):
if self.args[0].is_extended_real \
or self.args[0].is_complex:
return True
def _eval_is_zero(self):
rest, pi_mult = _peeloff_pi(self.args[0])
if rest.is_zero and pi_mult:
return (pi_mult - S.Half).is_integer
class tan(TrigonometricFunction):
"""
The tangent function.
Returns the tangent of x (measured in radians).
Explanation
===========
See :class:`sin` for notes about automatic evaluation.
Examples
========
>>> from sympy import tan, pi
>>> from sympy.abc import x
>>> tan(x**2).diff(x)
2*x*(tan(x**2)**2 + 1)
>>> tan(1).diff(x)
0
>>> tan(pi/8).expand()
-1 + sqrt(2)
See Also
========
sin, csc, cos, sec, cot
asin, acsc, acos, asec, atan, acot, atan2
References
==========
.. [1] https://en.wikipedia.org/wiki/Trigonometric_functions
.. [2] https://dlmf.nist.gov/4.14
.. [3] https://functions.wolfram.com/ElementaryFunctions/Tan
"""
def period(self, symbol=None):
return self._period(pi, symbol)
def fdiff(self, argindex=1):
if argindex == 1:
return S.One + self**2
else:
raise ArgumentIndexError(self, argindex)
def inverse(self, argindex=1):
"""
Returns the inverse of this function.
"""
return atan
@classmethod
def eval(cls, arg):
from sympy.calculus.accumulationbounds import AccumBounds
if arg.is_Number:
if arg is S.NaN:
return S.NaN
elif arg.is_zero:
return S.Zero
elif arg in (S.Infinity, S.NegativeInfinity):
return AccumBounds(S.NegativeInfinity, S.Infinity)
if arg is S.ComplexInfinity:
return S.NaN
if isinstance(arg, AccumBounds):
min, max = arg.min, arg.max
d = floor(min/pi)
if min is not S.NegativeInfinity:
min = min - d*pi
if max is not S.Infinity:
max = max - d*pi
from sympy.sets.sets import FiniteSet
if AccumBounds(min, max).intersection(FiniteSet(pi/2, pi*Rational(3, 2))):
return AccumBounds(S.NegativeInfinity, S.Infinity)
else:
return AccumBounds(tan(min), tan(max))
if arg.could_extract_minus_sign():
return -cls(-arg)
i_coeff = _imaginary_unit_as_coefficient(arg)
if i_coeff is not None:
from sympy.functions.elementary.hyperbolic import tanh
return S.ImaginaryUnit*tanh(i_coeff)
pi_coeff = _pi_coeff(arg, 2)
if pi_coeff is not None:
if pi_coeff.is_integer:
return S.Zero
if not pi_coeff.is_Rational:
narg = pi_coeff*pi
if narg != arg:
return cls(narg)
return None
if pi_coeff.is_Rational:
q = pi_coeff.q
p = pi_coeff.p % q
# ensure simplified results are returned for n*pi/5, n*pi/10
table10 = {
1: sqrt(1 - 2*sqrt(5)/5),
2: sqrt(5 - 2*sqrt(5)),
3: sqrt(1 + 2*sqrt(5)/5),
4: sqrt(5 + 2*sqrt(5))
}
if q in (5, 10):
n = 10*p/q
if n > 5:
n = 10 - n
return -table10[n]
else:
return table10[n]
if not pi_coeff.q % 2:
narg = pi_coeff*pi*2
cresult, sresult = cos(narg), cos(narg - pi/2)
if not isinstance(cresult, cos) \
and not isinstance(sresult, cos):
if sresult == 0:
return S.ComplexInfinity
return 1/sresult - cresult/sresult
table2 = _table2()
if q in table2:
a, b = table2[q]
nvala, nvalb = cls(p*pi/a), cls(p*pi/b)
if None in (nvala, nvalb):
return None
return (nvala - nvalb)/(1 + nvala*nvalb)
narg = ((pi_coeff + S.Half) % 1 - S.Half)*pi
# see cos() to specify which expressions should be
# expanded automatically in terms of radicals
cresult, sresult = cos(narg), cos(narg - pi/2)
if not isinstance(cresult, cos) \
and not isinstance(sresult, cos):
if cresult == 0:
return S.ComplexInfinity
return (sresult/cresult)
if narg != arg:
return cls(narg)
if arg.is_Add:
x, m = _peeloff_pi(arg)
if m:
tanm = tan(m*pi)
if tanm is S.ComplexInfinity:
return -cot(x)
else: # tanm == 0
return tan(x)
if arg.is_zero:
return S.Zero
if isinstance(arg, atan):
return arg.args[0]
if isinstance(arg, atan2):
y, x = arg.args
return y/x
if isinstance(arg, asin):
x = arg.args[0]
return x/sqrt(1 - x**2)
if isinstance(arg, acos):
x = arg.args[0]
return sqrt(1 - x**2)/x
if isinstance(arg, acot):
x = arg.args[0]
return 1/x
if isinstance(arg, acsc):
x = arg.args[0]
return 1/(sqrt(1 - 1/x**2)*x)
if isinstance(arg, asec):
x = arg.args[0]
return sqrt(1 - 1/x**2)*x
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
if n < 0 or n % 2 == 0:
return S.Zero
else:
x = sympify(x)
a, b = ((n - 1)//2), 2**(n + 1)
B = bernoulli(n + 1)
F = factorial(n + 1)
return S.NegativeOne**a*b*(b - 1)*B/F*x**n
def _eval_nseries(self, x, n, logx, cdir=0):
i = self.args[0].limit(x, 0)*2/pi
if i and i.is_Integer:
return self.rewrite(cos)._eval_nseries(x, n=n, logx=logx)
return Function._eval_nseries(self, x, n=n, logx=logx)
def _eval_rewrite_as_Pow(self, arg, **kwargs):
if isinstance(arg, log):
I = S.ImaginaryUnit
x = arg.args[0]
return I*(x**-I - x**I)/(x**-I + x**I)
def _eval_conjugate(self):
return self.func(self.args[0].conjugate())
def as_real_imag(self, deep=True, **hints):
re, im = self._as_real_imag(deep=deep, **hints)
if im:
from sympy.functions.elementary.hyperbolic import cosh, sinh
denom = cos(2*re) + cosh(2*im)
return (sin(2*re)/denom, sinh(2*im)/denom)
else:
return (self.func(re), S.Zero)
def _eval_expand_trig(self, **hints):
arg = self.args[0]
x = None
if arg.is_Add:
n = len(arg.args)
TX = []
for x in arg.args:
tx = tan(x, evaluate=False)._eval_expand_trig()
TX.append(tx)
Yg = numbered_symbols('Y')
Y = [ next(Yg) for i in range(n) ]
p = [0, 0]
for i in range(n + 1):
p[1 - i % 2] += symmetric_poly(i, Y)*(-1)**((i % 4)//2)
return (p[0]/p[1]).subs(list(zip(Y, TX)))
elif arg.is_Mul:
coeff, terms = arg.as_coeff_Mul(rational=True)
if coeff.is_Integer and coeff > 1:
I = S.ImaginaryUnit
z = Symbol('dummy', real=True)
P = ((1 + I*z)**coeff).expand()
return (im(P)/re(P)).subs([(z, tan(terms))])
return tan(arg)
def _eval_rewrite_as_exp(self, arg, **kwargs):
I = S.ImaginaryUnit
from sympy.functions.elementary.hyperbolic import HyperbolicFunction
if isinstance(arg, (TrigonometricFunction, HyperbolicFunction)):
arg = arg.func(arg.args[0]).rewrite(exp)
neg_exp, pos_exp = exp(-arg*I), exp(arg*I)
return I*(neg_exp - pos_exp)/(neg_exp + pos_exp)
def _eval_rewrite_as_sin(self, x, **kwargs):
return 2*sin(x)**2/sin(2*x)
def _eval_rewrite_as_cos(self, x, **kwargs):
return cos(x - pi/2, evaluate=False)/cos(x)
def _eval_rewrite_as_sincos(self, arg, **kwargs):
return sin(arg)/cos(arg)
def _eval_rewrite_as_cot(self, arg, **kwargs):
return 1/cot(arg)
def _eval_rewrite_as_sec(self, arg, **kwargs):
sin_in_sec_form = sin(arg).rewrite(sec, **kwargs)
cos_in_sec_form = cos(arg).rewrite(sec, **kwargs)
return sin_in_sec_form/cos_in_sec_form
def _eval_rewrite_as_csc(self, arg, **kwargs):
sin_in_csc_form = sin(arg).rewrite(csc, **kwargs)
cos_in_csc_form = cos(arg).rewrite(csc, **kwargs)
return sin_in_csc_form/cos_in_csc_form
def _eval_rewrite_as_pow(self, arg, **kwargs):
y = self.rewrite(cos, **kwargs).rewrite(pow, **kwargs)
if y.has(cos):
return None
return y
def _eval_rewrite_as_sqrt(self, arg, **kwargs):
y = self.rewrite(cos, **kwargs).rewrite(sqrt, **kwargs)
if y.has(cos):
return None
return y
def _eval_rewrite_as_besselj(self, arg, **kwargs):
from sympy.functions.special.bessel import besselj
return besselj(S.Half, arg)/besselj(-S.Half, arg)
def _eval_as_leading_term(self, x, logx=None, cdir=0):
from sympy.calculus.accumulationbounds import AccumBounds
from sympy.functions.elementary.complexes import re
arg = self.args[0]
x0 = arg.subs(x, 0).cancel()
n = 2*x0/pi
if n.is_integer:
lt = (arg - n*pi/2).as_leading_term(x)
return lt if n.is_even else -1/lt
if x0 is S.ComplexInfinity:
x0 = arg.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
if x0 in (S.Infinity, S.NegativeInfinity):
return AccumBounds(S.NegativeInfinity, S.Infinity)
return self.func(x0) if x0.is_finite else self
def _eval_is_extended_real(self):
# FIXME: currently tan(pi/2) return zoo
return self.args[0].is_extended_real
def _eval_is_real(self):
arg = self.args[0]
if arg.is_real and (arg/pi - S.Half).is_integer is False:
return True
def _eval_is_finite(self):
arg = self.args[0]
if arg.is_real and (arg/pi - S.Half).is_integer is False:
return True
if arg.is_imaginary:
return True
def _eval_is_zero(self):
rest, pi_mult = _peeloff_pi(self.args[0])
if rest.is_zero:
return pi_mult.is_integer
def _eval_is_complex(self):
arg = self.args[0]
if arg.is_real and (arg/pi - S.Half).is_integer is False:
return True
class cot(TrigonometricFunction):
"""
The cotangent function.
Returns the cotangent of x (measured in radians).
Explanation
===========
See :class:`sin` for notes about automatic evaluation.
Examples
========
>>> from sympy import cot, pi
>>> from sympy.abc import x
>>> cot(x**2).diff(x)
2*x*(-cot(x**2)**2 - 1)
>>> cot(1).diff(x)
0
>>> cot(pi/12)
sqrt(3) + 2
See Also
========
sin, csc, cos, sec, tan
asin, acsc, acos, asec, atan, acot, atan2
References
==========
.. [1] https://en.wikipedia.org/wiki/Trigonometric_functions
.. [2] https://dlmf.nist.gov/4.14
.. [3] https://functions.wolfram.com/ElementaryFunctions/Cot
"""
def period(self, symbol=None):
return self._period(pi, symbol)
def fdiff(self, argindex=1):
if argindex == 1:
return S.NegativeOne - self**2
else:
raise ArgumentIndexError(self, argindex)
def inverse(self, argindex=1):
"""
Returns the inverse of this function.
"""
return acot
@classmethod
def eval(cls, arg):
from sympy.calculus.accumulationbounds import AccumBounds
if arg.is_Number:
if arg is S.NaN:
return S.NaN
if arg.is_zero:
return S.ComplexInfinity
elif arg in (S.Infinity, S.NegativeInfinity):
return AccumBounds(S.NegativeInfinity, S.Infinity)
if arg is S.ComplexInfinity:
return S.NaN
if isinstance(arg, AccumBounds):
return -tan(arg + pi/2)
if arg.could_extract_minus_sign():
return -cls(-arg)
i_coeff = _imaginary_unit_as_coefficient(arg)
if i_coeff is not None:
from sympy.functions.elementary.hyperbolic import coth
return -S.ImaginaryUnit*coth(i_coeff)
pi_coeff = _pi_coeff(arg, 2)
if pi_coeff is not None:
if pi_coeff.is_integer:
return S.ComplexInfinity
if not pi_coeff.is_Rational:
narg = pi_coeff*pi
if narg != arg:
return cls(narg)
return None
if pi_coeff.is_Rational:
if pi_coeff.q in (5, 10):
return tan(pi/2 - arg)
if pi_coeff.q > 2 and not pi_coeff.q % 2:
narg = pi_coeff*pi*2
cresult, sresult = cos(narg), cos(narg - pi/2)
if not isinstance(cresult, cos) \
and not isinstance(sresult, cos):
return 1/sresult + cresult/sresult
q = pi_coeff.q
p = pi_coeff.p % q
table2 = _table2()
if q in table2:
a, b = table2[q]
nvala, nvalb = cls(p*pi/a), cls(p*pi/b)
if None in (nvala, nvalb):
return None
return (1 + nvala*nvalb)/(nvalb - nvala)
narg = (((pi_coeff + S.Half) % 1) - S.Half)*pi
# see cos() to specify which expressions should be
# expanded automatically in terms of radicals
cresult, sresult = cos(narg), cos(narg - pi/2)
if not isinstance(cresult, cos) \
and not isinstance(sresult, cos):
if sresult == 0:
return S.ComplexInfinity
return cresult/sresult
if narg != arg:
return cls(narg)
if arg.is_Add:
x, m = _peeloff_pi(arg)
if m:
cotm = cot(m*pi)
if cotm is S.ComplexInfinity:
return cot(x)
else: # cotm == 0
return -tan(x)
if arg.is_zero:
return S.ComplexInfinity
if isinstance(arg, acot):
return arg.args[0]
if isinstance(arg, atan):
x = arg.args[0]
return 1/x
if isinstance(arg, atan2):
y, x = arg.args
return x/y
if isinstance(arg, asin):
x = arg.args[0]
return sqrt(1 - x**2)/x
if isinstance(arg, acos):
x = arg.args[0]
return x/sqrt(1 - x**2)
if isinstance(arg, acsc):
x = arg.args[0]
return sqrt(1 - 1/x**2)*x
if isinstance(arg, asec):
x = arg.args[0]
return 1/(sqrt(1 - 1/x**2)*x)
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
if n == 0:
return 1/sympify(x)
elif n < 0 or n % 2 == 0:
return S.Zero
else:
x = sympify(x)
B = bernoulli(n + 1)
F = factorial(n + 1)
return S.NegativeOne**((n + 1)//2)*2**(n + 1)*B/F*x**n
def _eval_nseries(self, x, n, logx, cdir=0):
i = self.args[0].limit(x, 0)/pi
if i and i.is_Integer:
return self.rewrite(cos)._eval_nseries(x, n=n, logx=logx)
return self.rewrite(tan)._eval_nseries(x, n=n, logx=logx)
def _eval_conjugate(self):
return self.func(self.args[0].conjugate())
def as_real_imag(self, deep=True, **hints):
re, im = self._as_real_imag(deep=deep, **hints)
if im:
from sympy.functions.elementary.hyperbolic import cosh, sinh
denom = cos(2*re) - cosh(2*im)
return (-sin(2*re)/denom, sinh(2*im)/denom)
else:
return (self.func(re), S.Zero)
def _eval_rewrite_as_exp(self, arg, **kwargs):
from sympy.functions.elementary.hyperbolic import HyperbolicFunction
I = S.ImaginaryUnit
if isinstance(arg, (TrigonometricFunction, HyperbolicFunction)):
arg = arg.func(arg.args[0]).rewrite(exp, **kwargs)
neg_exp, pos_exp = exp(-arg*I), exp(arg*I)
return I*(pos_exp + neg_exp)/(pos_exp - neg_exp)
def _eval_rewrite_as_Pow(self, arg, **kwargs):
if isinstance(arg, log):
I = S.ImaginaryUnit
x = arg.args[0]
return -I*(x**-I + x**I)/(x**-I - x**I)
def _eval_rewrite_as_sin(self, x, **kwargs):
return sin(2*x)/(2*(sin(x)**2))
def _eval_rewrite_as_cos(self, x, **kwargs):
return cos(x)/cos(x - pi/2, evaluate=False)
def _eval_rewrite_as_sincos(self, arg, **kwargs):
return cos(arg)/sin(arg)
def _eval_rewrite_as_tan(self, arg, **kwargs):
return 1/tan(arg)
def _eval_rewrite_as_sec(self, arg, **kwargs):
cos_in_sec_form = cos(arg).rewrite(sec, **kwargs)
sin_in_sec_form = sin(arg).rewrite(sec, **kwargs)
return cos_in_sec_form/sin_in_sec_form
def _eval_rewrite_as_csc(self, arg, **kwargs):
cos_in_csc_form = cos(arg).rewrite(csc, **kwargs)
sin_in_csc_form = sin(arg).rewrite(csc, **kwargs)
return cos_in_csc_form/sin_in_csc_form
def _eval_rewrite_as_pow(self, arg, **kwargs):
y = self.rewrite(cos, **kwargs).rewrite(pow, **kwargs)
if y.has(cos):
return None
return y
def _eval_rewrite_as_sqrt(self, arg, **kwargs):
y = self.rewrite(cos, **kwargs).rewrite(sqrt, **kwargs)
if y.has(cos):
return None
return y
def _eval_rewrite_as_besselj(self, arg, **kwargs):
from sympy.functions.special.bessel import besselj
return besselj(-S.Half, arg)/besselj(S.Half, arg)
def _eval_as_leading_term(self, x, logx=None, cdir=0):
from sympy.calculus.accumulationbounds import AccumBounds
from sympy.functions.elementary.complexes import re
arg = self.args[0]
x0 = arg.subs(x, 0).cancel()
n = 2*x0/pi
if n.is_integer:
lt = (arg - n*pi/2).as_leading_term(x)
return 1/lt if n.is_even else -lt
if x0 is S.ComplexInfinity:
x0 = arg.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
if x0 in (S.Infinity, S.NegativeInfinity):
return AccumBounds(S.NegativeInfinity, S.Infinity)
return self.func(x0) if x0.is_finite else self
def _eval_is_extended_real(self):
return self.args[0].is_extended_real
def _eval_expand_trig(self, **hints):
arg = self.args[0]
x = None
if arg.is_Add:
n = len(arg.args)
CX = []
for x in arg.args:
cx = cot(x, evaluate=False)._eval_expand_trig()
CX.append(cx)
Yg = numbered_symbols('Y')
Y = [ next(Yg) for i in range(n) ]
p = [0, 0]
for i in range(n, -1, -1):
p[(n - i) % 2] += symmetric_poly(i, Y)*(-1)**(((n - i) % 4)//2)
return (p[0]/p[1]).subs(list(zip(Y, CX)))
elif arg.is_Mul:
coeff, terms = arg.as_coeff_Mul(rational=True)
if coeff.is_Integer and coeff > 1:
I = S.ImaginaryUnit
z = Symbol('dummy', real=True)
P = ((z + I)**coeff).expand()
return (re(P)/im(P)).subs([(z, cot(terms))])
return cot(arg) # XXX sec and csc return 1/cos and 1/sin
def _eval_is_finite(self):
arg = self.args[0]
if arg.is_real and (arg/pi).is_integer is False:
return True
if arg.is_imaginary:
return True
def _eval_is_real(self):
arg = self.args[0]
if arg.is_real and (arg/pi).is_integer is False:
return True
def _eval_is_complex(self):
arg = self.args[0]
if arg.is_real and (arg/pi).is_integer is False:
return True
def _eval_is_zero(self):
rest, pimult = _peeloff_pi(self.args[0])
if pimult and rest.is_zero:
return (pimult - S.Half).is_integer
def _eval_subs(self, old, new):
arg = self.args[0]
argnew = arg.subs(old, new)
if arg != argnew and (argnew/pi).is_integer:
return S.ComplexInfinity
return cot(argnew)
class ReciprocalTrigonometricFunction(TrigonometricFunction):
"""Base class for reciprocal functions of trigonometric functions. """
_reciprocal_of = None # mandatory, to be defined in subclass
_singularities = (S.ComplexInfinity,)
# _is_even and _is_odd are used for correct evaluation of csc(-x), sec(-x)
# TODO refactor into TrigonometricFunction common parts of
# trigonometric functions eval() like even/odd, func(x+2*k*pi), etc.
# optional, to be defined in subclasses:
_is_even: FuzzyBool = None
_is_odd: FuzzyBool = None
@classmethod
def eval(cls, arg):
if arg.could_extract_minus_sign():
if cls._is_even:
return cls(-arg)
if cls._is_odd:
return -cls(-arg)
pi_coeff = _pi_coeff(arg)
if (pi_coeff is not None
and not (2*pi_coeff).is_integer
and pi_coeff.is_Rational):
q = pi_coeff.q
p = pi_coeff.p % (2*q)
if p > q:
narg = (pi_coeff - 1)*pi
return -cls(narg)
if 2*p > q:
narg = (1 - pi_coeff)*pi
if cls._is_odd:
return cls(narg)
elif cls._is_even:
return -cls(narg)
if hasattr(arg, 'inverse') and arg.inverse() == cls:
return arg.args[0]
t = cls._reciprocal_of.eval(arg)
if t is None:
return t
elif any(isinstance(i, cos) for i in (t, -t)):
return (1/t).rewrite(sec)
elif any(isinstance(i, sin) for i in (t, -t)):
return (1/t).rewrite(csc)
else:
return 1/t
def _call_reciprocal(self, method_name, *args, **kwargs):
# Calls method_name on _reciprocal_of
o = self._reciprocal_of(self.args[0])
return getattr(o, method_name)(*args, **kwargs)
def _calculate_reciprocal(self, method_name, *args, **kwargs):
# If calling method_name on _reciprocal_of returns a value != None
# then return the reciprocal of that value
t = self._call_reciprocal(method_name, *args, **kwargs)
return 1/t if t is not None else t
def _rewrite_reciprocal(self, method_name, arg):
# Special handling for rewrite functions. If reciprocal rewrite returns
# unmodified expression, then return None
t = self._call_reciprocal(method_name, arg)
if t is not None and t != self._reciprocal_of(arg):
return 1/t
def _period(self, symbol):
f = expand_mul(self.args[0])
return self._reciprocal_of(f).period(symbol)
def fdiff(self, argindex=1):
return -self._calculate_reciprocal("fdiff", argindex)/self**2
def _eval_rewrite_as_exp(self, arg, **kwargs):
return self._rewrite_reciprocal("_eval_rewrite_as_exp", arg)
def _eval_rewrite_as_Pow(self, arg, **kwargs):
return self._rewrite_reciprocal("_eval_rewrite_as_Pow", arg)
def _eval_rewrite_as_sin(self, arg, **kwargs):
return self._rewrite_reciprocal("_eval_rewrite_as_sin", arg)
def _eval_rewrite_as_cos(self, arg, **kwargs):
return self._rewrite_reciprocal("_eval_rewrite_as_cos", arg)
def _eval_rewrite_as_tan(self, arg, **kwargs):
return self._rewrite_reciprocal("_eval_rewrite_as_tan", arg)
def _eval_rewrite_as_pow(self, arg, **kwargs):
return self._rewrite_reciprocal("_eval_rewrite_as_pow", arg)
def _eval_rewrite_as_sqrt(self, arg, **kwargs):
return self._rewrite_reciprocal("_eval_rewrite_as_sqrt", arg)
def _eval_conjugate(self):
return self.func(self.args[0].conjugate())
def as_real_imag(self, deep=True, **hints):
return (1/self._reciprocal_of(self.args[0])).as_real_imag(deep,
**hints)
def _eval_expand_trig(self, **hints):
return self._calculate_reciprocal("_eval_expand_trig", **hints)
def _eval_is_extended_real(self):
return self._reciprocal_of(self.args[0])._eval_is_extended_real()
def _eval_as_leading_term(self, x, logx=None, cdir=0):
return (1/self._reciprocal_of(self.args[0]))._eval_as_leading_term(x)
def _eval_is_finite(self):
return (1/self._reciprocal_of(self.args[0])).is_finite
def _eval_nseries(self, x, n, logx, cdir=0):
return (1/self._reciprocal_of(self.args[0]))._eval_nseries(x, n, logx)
class sec(ReciprocalTrigonometricFunction):
"""
The secant function.
Returns the secant of x (measured in radians).
Explanation
===========
See :class:`sin` for notes about automatic evaluation.
Examples
========
>>> from sympy import sec
>>> from sympy.abc import x
>>> sec(x**2).diff(x)
2*x*tan(x**2)*sec(x**2)
>>> sec(1).diff(x)
0
See Also
========
sin, csc, cos, tan, cot
asin, acsc, acos, asec, atan, acot, atan2
References
==========
.. [1] https://en.wikipedia.org/wiki/Trigonometric_functions
.. [2] https://dlmf.nist.gov/4.14
.. [3] https://functions.wolfram.com/ElementaryFunctions/Sec
"""
_reciprocal_of = cos
_is_even = True
def period(self, symbol=None):
return self._period(symbol)
def _eval_rewrite_as_cot(self, arg, **kwargs):
cot_half_sq = cot(arg/2)**2
return (cot_half_sq + 1)/(cot_half_sq - 1)
def _eval_rewrite_as_cos(self, arg, **kwargs):
return (1/cos(arg))
def _eval_rewrite_as_sincos(self, arg, **kwargs):
return sin(arg)/(cos(arg)*sin(arg))
def _eval_rewrite_as_sin(self, arg, **kwargs):
return (1/cos(arg).rewrite(sin, **kwargs))
def _eval_rewrite_as_tan(self, arg, **kwargs):
return (1/cos(arg).rewrite(tan, **kwargs))
def _eval_rewrite_as_csc(self, arg, **kwargs):
return csc(pi/2 - arg, evaluate=False)
def fdiff(self, argindex=1):
if argindex == 1:
return tan(self.args[0])*sec(self.args[0])
else:
raise ArgumentIndexError(self, argindex)
def _eval_rewrite_as_besselj(self, arg, **kwargs):
from sympy.functions.special.bessel import besselj
return Piecewise(
(1/(sqrt(pi*arg)/(sqrt(2))*besselj(-S.Half, arg)), Ne(arg, 0)),
(1, True)
)
def _eval_is_complex(self):
arg = self.args[0]
if arg.is_complex and (arg/pi - S.Half).is_integer is False:
return True
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
# Reference Formula:
# https://functions.wolfram.com/ElementaryFunctions/Sec/06/01/02/01/
if n < 0 or n % 2 == 1:
return S.Zero
else:
x = sympify(x)
k = n//2
return S.NegativeOne**k*euler(2*k)/factorial(2*k)*x**(2*k)
def _eval_as_leading_term(self, x, logx=None, cdir=0):
from sympy.calculus.accumulationbounds import AccumBounds
from sympy.functions.elementary.complexes import re
arg = self.args[0]
x0 = arg.subs(x, 0).cancel()
n = (x0 + pi/2)/pi
if n.is_integer:
lt = (arg - n*pi + pi/2).as_leading_term(x)
return (S.NegativeOne**n)/lt
if x0 is S.ComplexInfinity:
x0 = arg.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
if x0 in (S.Infinity, S.NegativeInfinity):
return AccumBounds(S.NegativeInfinity, S.Infinity)
return self.func(x0) if x0.is_finite else self
class csc(ReciprocalTrigonometricFunction):
"""
The cosecant function.
Returns the cosecant of x (measured in radians).
Explanation
===========
See :func:`sin` for notes about automatic evaluation.
Examples
========
>>> from sympy import csc
>>> from sympy.abc import x
>>> csc(x**2).diff(x)
-2*x*cot(x**2)*csc(x**2)
>>> csc(1).diff(x)
0
See Also
========
sin, cos, sec, tan, cot
asin, acsc, acos, asec, atan, acot, atan2
References
==========
.. [1] https://en.wikipedia.org/wiki/Trigonometric_functions
.. [2] https://dlmf.nist.gov/4.14
.. [3] https://functions.wolfram.com/ElementaryFunctions/Csc
"""
_reciprocal_of = sin
_is_odd = True
def period(self, symbol=None):
return self._period(symbol)
def _eval_rewrite_as_sin(self, arg, **kwargs):
return (1/sin(arg))
def _eval_rewrite_as_sincos(self, arg, **kwargs):
return cos(arg)/(sin(arg)*cos(arg))
def _eval_rewrite_as_cot(self, arg, **kwargs):
cot_half = cot(arg/2)
return (1 + cot_half**2)/(2*cot_half)
def _eval_rewrite_as_cos(self, arg, **kwargs):
return 1/sin(arg).rewrite(cos, **kwargs)
def _eval_rewrite_as_sec(self, arg, **kwargs):
return sec(pi/2 - arg, evaluate=False)
def _eval_rewrite_as_tan(self, arg, **kwargs):
return (1/sin(arg).rewrite(tan, **kwargs))
def _eval_rewrite_as_besselj(self, arg, **kwargs):
from sympy.functions.special.bessel import besselj
return sqrt(2/pi)*(1/(sqrt(arg)*besselj(S.Half, arg)))
def fdiff(self, argindex=1):
if argindex == 1:
return -cot(self.args[0])*csc(self.args[0])
else:
raise ArgumentIndexError(self, argindex)
def _eval_is_complex(self):
arg = self.args[0]
if arg.is_real and (arg/pi).is_integer is False:
return True
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
if n == 0:
return 1/sympify(x)
elif n < 0 or n % 2 == 0:
return S.Zero
else:
x = sympify(x)
k = n//2 + 1
return (S.NegativeOne**(k - 1)*2*(2**(2*k - 1) - 1)*
bernoulli(2*k)*x**(2*k - 1)/factorial(2*k))
def _eval_as_leading_term(self, x, logx=None, cdir=0):
from sympy.calculus.accumulationbounds import AccumBounds
from sympy.functions.elementary.complexes import re
arg = self.args[0]
x0 = arg.subs(x, 0).cancel()
n = x0/pi
if n.is_integer:
lt = (arg - n*pi).as_leading_term(x)
return (S.NegativeOne**n)/lt
if x0 is S.ComplexInfinity:
x0 = arg.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
if x0 in (S.Infinity, S.NegativeInfinity):
return AccumBounds(S.NegativeInfinity, S.Infinity)
return self.func(x0) if x0.is_finite else self
class sinc(Function):
r"""
Represents an unnormalized sinc function:
.. math::
\operatorname{sinc}(x) =
\begin{cases}
\frac{\sin x}{x} & \qquad x \neq 0 \\
1 & \qquad x = 0
\end{cases}
Examples
========
>>> from sympy import sinc, oo, jn
>>> from sympy.abc import x
>>> sinc(x)
sinc(x)
* Automated Evaluation
>>> sinc(0)
1
>>> sinc(oo)
0
* Differentiation
>>> sinc(x).diff()
cos(x)/x - sin(x)/x**2
* Series Expansion
>>> sinc(x).series()
1 - x**2/6 + x**4/120 + O(x**6)
* As zero'th order spherical Bessel Function
>>> sinc(x).rewrite(jn)
jn(0, x)
See also
========
sin
References
==========
.. [1] https://en.wikipedia.org/wiki/Sinc_function
"""
_singularities = (S.ComplexInfinity,)
def fdiff(self, argindex=1):
x = self.args[0]
if argindex == 1:
# We would like to return the Piecewise here, but Piecewise.diff
# currently can't handle removable singularities, meaning things
# like sinc(x).diff(x, 2) give the wrong answer at x = 0. See
# https://github.com/sympy/sympy/issues/11402.
#
# return Piecewise(((x*cos(x) - sin(x))/x**2, Ne(x, S.Zero)), (S.Zero, S.true))
return cos(x)/x - sin(x)/x**2
else:
raise ArgumentIndexError(self, argindex)
@classmethod
def eval(cls, arg):
if arg.is_zero:
return S.One
if arg.is_Number:
if arg in [S.Infinity, S.NegativeInfinity]:
return S.Zero
elif arg is S.NaN:
return S.NaN
if arg is S.ComplexInfinity:
return S.NaN
if arg.could_extract_minus_sign():
return cls(-arg)
pi_coeff = _pi_coeff(arg)
if pi_coeff is not None:
if pi_coeff.is_integer:
if fuzzy_not(arg.is_zero):
return S.Zero
elif (2*pi_coeff).is_integer:
return S.NegativeOne**(pi_coeff - S.Half)/arg
def _eval_nseries(self, x, n, logx, cdir=0):
x = self.args[0]
return (sin(x)/x)._eval_nseries(x, n, logx)
def _eval_rewrite_as_jn(self, arg, **kwargs):
from sympy.functions.special.bessel import jn
return jn(0, arg)
def _eval_rewrite_as_sin(self, arg, **kwargs):
return Piecewise((sin(arg)/arg, Ne(arg, S.Zero)), (S.One, S.true))
def _eval_is_zero(self):
if self.args[0].is_infinite:
return True
rest, pi_mult = _peeloff_pi(self.args[0])
if rest.is_zero:
return fuzzy_and([pi_mult.is_integer, pi_mult.is_nonzero])
if rest.is_Number and pi_mult.is_integer:
return False
def _eval_is_real(self):
if self.args[0].is_extended_real or self.args[0].is_imaginary:
return True
_eval_is_finite = _eval_is_real
###############################################################################
########################### TRIGONOMETRIC INVERSES ############################
###############################################################################
class InverseTrigonometricFunction(Function):
"""Base class for inverse trigonometric functions."""
_singularities = (S.One, S.NegativeOne, S.Zero, S.ComplexInfinity) # type: tTuple[Expr, ...]
@staticmethod
@cacheit
def _asin_table():
# Only keys with could_extract_minus_sign() == False
# are actually needed.
return {
sqrt(3)/2: pi/3,
sqrt(2)/2: pi/4,
1/sqrt(2): pi/4,
sqrt((5 - sqrt(5))/8): pi/5,
sqrt(2)*sqrt(5 - sqrt(5))/4: pi/5,
sqrt((5 + sqrt(5))/8): pi*Rational(2, 5),
sqrt(2)*sqrt(5 + sqrt(5))/4: pi*Rational(2, 5),
S.Half: pi/6,
sqrt(2 - sqrt(2))/2: pi/8,
sqrt(S.Half - sqrt(2)/4): pi/8,
sqrt(2 + sqrt(2))/2: pi*Rational(3, 8),
sqrt(S.Half + sqrt(2)/4): pi*Rational(3, 8),
(sqrt(5) - 1)/4: pi/10,
(1 - sqrt(5))/4: -pi/10,
(sqrt(5) + 1)/4: pi*Rational(3, 10),
sqrt(6)/4 - sqrt(2)/4: pi/12,
-sqrt(6)/4 + sqrt(2)/4: -pi/12,
(sqrt(3) - 1)/sqrt(8): pi/12,
(1 - sqrt(3))/sqrt(8): -pi/12,
sqrt(6)/4 + sqrt(2)/4: pi*Rational(5, 12),
(1 + sqrt(3))/sqrt(8): pi*Rational(5, 12)
}
@staticmethod
@cacheit
def _atan_table():
# Only keys with could_extract_minus_sign() == False
# are actually needed.
return {
sqrt(3)/3: pi/6,
1/sqrt(3): pi/6,
sqrt(3): pi/3,
sqrt(2) - 1: pi/8,
1 - sqrt(2): -pi/8,
1 + sqrt(2): pi*Rational(3, 8),
sqrt(5 - 2*sqrt(5)): pi/5,
sqrt(5 + 2*sqrt(5)): pi*Rational(2, 5),
sqrt(1 - 2*sqrt(5)/5): pi/10,
sqrt(1 + 2*sqrt(5)/5): pi*Rational(3, 10),
2 - sqrt(3): pi/12,
-2 + sqrt(3): -pi/12,
2 + sqrt(3): pi*Rational(5, 12)
}
@staticmethod
@cacheit
def _acsc_table():
# Keys for which could_extract_minus_sign()
# will obviously return True are omitted.
return {
2*sqrt(3)/3: pi/3,
sqrt(2): pi/4,
sqrt(2 + 2*sqrt(5)/5): pi/5,
1/sqrt(Rational(5, 8) - sqrt(5)/8): pi/5,
sqrt(2 - 2*sqrt(5)/5): pi*Rational(2, 5),
1/sqrt(Rational(5, 8) + sqrt(5)/8): pi*Rational(2, 5),
2: pi/6,
sqrt(4 + 2*sqrt(2)): pi/8,
2/sqrt(2 - sqrt(2)): pi/8,
sqrt(4 - 2*sqrt(2)): pi*Rational(3, 8),
2/sqrt(2 + sqrt(2)): pi*Rational(3, 8),
1 + sqrt(5): pi/10,
sqrt(5) - 1: pi*Rational(3, 10),
-(sqrt(5) - 1): pi*Rational(-3, 10),
sqrt(6) + sqrt(2): pi/12,
sqrt(6) - sqrt(2): pi*Rational(5, 12),
-(sqrt(6) - sqrt(2)): pi*Rational(-5, 12)
}
class asin(InverseTrigonometricFunction):
r"""
The inverse sine function.
Returns the arcsine of x in radians.
Explanation
===========
``asin(x)`` will evaluate automatically in the cases
$x \in \{\infty, -\infty, 0, 1, -1\}$ and for some instances when the
result is a rational multiple of $\pi$ (see the ``eval`` class method).
A purely imaginary argument will lead to an asinh expression.
Examples
========
>>> from sympy import asin, oo
>>> asin(1)
pi/2
>>> asin(-1)
-pi/2
>>> asin(-oo)
oo*I
>>> asin(oo)
-oo*I
See Also
========
sin, csc, cos, sec, tan, cot
acsc, acos, asec, atan, acot, atan2
References
==========
.. [1] https://en.wikipedia.org/wiki/Inverse_trigonometric_functions
.. [2] https://dlmf.nist.gov/4.23
.. [3] https://functions.wolfram.com/ElementaryFunctions/ArcSin
"""
def fdiff(self, argindex=1):
if argindex == 1:
return 1/sqrt(1 - self.args[0]**2)
else:
raise ArgumentIndexError(self, argindex)
def _eval_is_rational(self):
s = self.func(*self.args)
if s.func == self.func:
if s.args[0].is_rational:
return False
else:
return s.is_rational
def _eval_is_positive(self):
return self._eval_is_extended_real() and self.args[0].is_positive
def _eval_is_negative(self):
return self._eval_is_extended_real() and self.args[0].is_negative
@classmethod
def eval(cls, arg):
if arg.is_Number:
if arg is S.NaN:
return S.NaN
elif arg is S.Infinity:
return S.NegativeInfinity*S.ImaginaryUnit
elif arg is S.NegativeInfinity:
return S.Infinity*S.ImaginaryUnit
elif arg.is_zero:
return S.Zero
elif arg is S.One:
return pi/2
elif arg is S.NegativeOne:
return -pi/2
if arg is S.ComplexInfinity:
return S.ComplexInfinity
if arg.could_extract_minus_sign():
return -cls(-arg)
if arg.is_number:
asin_table = cls._asin_table()
if arg in asin_table:
return asin_table[arg]
i_coeff = _imaginary_unit_as_coefficient(arg)
if i_coeff is not None:
from sympy.functions.elementary.hyperbolic import asinh
return S.ImaginaryUnit*asinh(i_coeff)
if arg.is_zero:
return S.Zero
if isinstance(arg, sin):
ang = arg.args[0]
if ang.is_comparable:
ang %= 2*pi # restrict to [0,2*pi)
if ang > pi: # restrict to (-pi,pi]
ang = pi - ang
# restrict to [-pi/2,pi/2]
if ang > pi/2:
ang = pi - ang
if ang < -pi/2:
ang = -pi - ang
return ang
if isinstance(arg, cos): # acos(x) + asin(x) = pi/2
ang = arg.args[0]
if ang.is_comparable:
return pi/2 - acos(arg)
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
if n < 0 or n % 2 == 0:
return S.Zero
else:
x = sympify(x)
if len(previous_terms) >= 2 and n > 2:
p = previous_terms[-2]
return p*(n - 2)**2/(n*(n - 1))*x**2
else:
k = (n - 1) // 2
R = RisingFactorial(S.Half, k)
F = factorial(k)
return R/F*x**n/n
def _eval_as_leading_term(self, x, logx=None, cdir=0): # asin
arg = self.args[0]
x0 = arg.subs(x, 0).cancel()
if x0 is S.NaN:
return self.func(arg.as_leading_term(x))
if x0.is_zero:
return arg.as_leading_term(x)
# Handling branch points
if x0 in (-S.One, S.One, S.ComplexInfinity):
return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir).expand()
# Handling points lying on branch cuts (-oo, -1) U (1, oo)
if (1 - x0**2).is_negative:
ndir = arg.dir(x, cdir if cdir else 1)
if im(ndir).is_negative:
if x0.is_negative:
return -pi - self.func(x0)
elif im(ndir).is_positive:
if x0.is_positive:
return pi - self.func(x0)
else:
return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir).expand()
return self.func(x0)
def _eval_nseries(self, x, n, logx, cdir=0): # asin
from sympy.series.order import O
arg0 = self.args[0].subs(x, 0)
# Handling branch points
if arg0 is S.One:
t = Dummy('t', positive=True)
ser = asin(S.One - t**2).rewrite(log).nseries(t, 0, 2*n)
arg1 = S.One - self.args[0]
f = arg1.as_leading_term(x)
g = (arg1 - f)/ f
if not g.is_meromorphic(x, 0): # cannot be expanded
return O(1) if n == 0 else pi/2 + O(sqrt(x))
res1 = sqrt(S.One + g)._eval_nseries(x, n=n, logx=logx)
res = (res1.removeO()*sqrt(f)).expand()
return ser.removeO().subs(t, res).expand().powsimp() + O(x**n, x)
if arg0 is S.NegativeOne:
t = Dummy('t', positive=True)
ser = asin(S.NegativeOne + t**2).rewrite(log).nseries(t, 0, 2*n)
arg1 = S.One + self.args[0]
f = arg1.as_leading_term(x)
g = (arg1 - f)/ f
if not g.is_meromorphic(x, 0): # cannot be expanded
return O(1) if n == 0 else -pi/2 + O(sqrt(x))
res1 = sqrt(S.One + g)._eval_nseries(x, n=n, logx=logx)
res = (res1.removeO()*sqrt(f)).expand()
return ser.removeO().subs(t, res).expand().powsimp() + O(x**n, x)
res = Function._eval_nseries(self, x, n=n, logx=logx)
if arg0 is S.ComplexInfinity:
return res
# Handling points lying on branch cuts (-oo, -1) U (1, oo)
if (1 - arg0**2).is_negative:
ndir = self.args[0].dir(x, cdir if cdir else 1)
if im(ndir).is_negative:
if arg0.is_negative:
return -pi - res
elif im(ndir).is_positive:
if arg0.is_positive:
return pi - res
else:
return self.rewrite(log)._eval_nseries(x, n, logx=logx, cdir=cdir)
return res
def _eval_rewrite_as_acos(self, x, **kwargs):
return pi/2 - acos(x)
def _eval_rewrite_as_atan(self, x, **kwargs):
return 2*atan(x/(1 + sqrt(1 - x**2)))
def _eval_rewrite_as_log(self, x, **kwargs):
return -S.ImaginaryUnit*log(S.ImaginaryUnit*x + sqrt(1 - x**2))
_eval_rewrite_as_tractable = _eval_rewrite_as_log
def _eval_rewrite_as_acot(self, arg, **kwargs):
return 2*acot((1 + sqrt(1 - arg**2))/arg)
def _eval_rewrite_as_asec(self, arg, **kwargs):
return pi/2 - asec(1/arg)
def _eval_rewrite_as_acsc(self, arg, **kwargs):
return acsc(1/arg)
def _eval_is_extended_real(self):
x = self.args[0]
return x.is_extended_real and (1 - abs(x)).is_nonnegative
def inverse(self, argindex=1):
"""
Returns the inverse of this function.
"""
return sin
class acos(InverseTrigonometricFunction):
r"""
The inverse cosine function.
Explanation
===========
Returns the arc cosine of x (measured in radians).
``acos(x)`` will evaluate automatically in the cases
$x \in \{\infty, -\infty, 0, 1, -1\}$ and for some instances when
the result is a rational multiple of $\pi$ (see the eval class method).
``acos(zoo)`` evaluates to ``zoo``
(see note in :class:`sympy.functions.elementary.trigonometric.asec`)
A purely imaginary argument will be rewritten to asinh.
Examples
========
>>> from sympy import acos, oo
>>> acos(1)
0
>>> acos(0)
pi/2
>>> acos(oo)
oo*I
See Also
========
sin, csc, cos, sec, tan, cot
asin, acsc, asec, atan, acot, atan2
References
==========
.. [1] https://en.wikipedia.org/wiki/Inverse_trigonometric_functions
.. [2] https://dlmf.nist.gov/4.23
.. [3] https://functions.wolfram.com/ElementaryFunctions/ArcCos
"""
def fdiff(self, argindex=1):
if argindex == 1:
return -1/sqrt(1 - self.args[0]**2)
else:
raise ArgumentIndexError(self, argindex)
def _eval_is_rational(self):
s = self.func(*self.args)
if s.func == self.func:
if s.args[0].is_rational:
return False
else:
return s.is_rational
@classmethod
def eval(cls, arg):
if arg.is_Number:
if arg is S.NaN:
return S.NaN
elif arg is S.Infinity:
return S.Infinity*S.ImaginaryUnit
elif arg is S.NegativeInfinity:
return S.NegativeInfinity*S.ImaginaryUnit
elif arg.is_zero:
return pi/2
elif arg is S.One:
return S.Zero
elif arg is S.NegativeOne:
return pi
if arg is S.ComplexInfinity:
return S.ComplexInfinity
if arg.is_number:
asin_table = cls._asin_table()
if arg in asin_table:
return pi/2 - asin_table[arg]
elif -arg in asin_table:
return pi/2 + asin_table[-arg]
i_coeff = _imaginary_unit_as_coefficient(arg)
if i_coeff is not None:
return pi/2 - asin(arg)
if isinstance(arg, cos):
ang = arg.args[0]
if ang.is_comparable:
ang %= 2*pi # restrict to [0,2*pi)
if ang > pi: # restrict to [0,pi]
ang = 2*pi - ang
return ang
if isinstance(arg, sin): # acos(x) + asin(x) = pi/2
ang = arg.args[0]
if ang.is_comparable:
return pi/2 - asin(arg)
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
if n == 0:
return pi/2
elif n < 0 or n % 2 == 0:
return S.Zero
else:
x = sympify(x)
if len(previous_terms) >= 2 and n > 2:
p = previous_terms[-2]
return p*(n - 2)**2/(n*(n - 1))*x**2
else:
k = (n - 1) // 2
R = RisingFactorial(S.Half, k)
F = factorial(k)
return -R/F*x**n/n
def _eval_as_leading_term(self, x, logx=None, cdir=0): # acos
arg = self.args[0]
x0 = arg.subs(x, 0).cancel()
if x0 is S.NaN:
return self.func(arg.as_leading_term(x))
# Handling branch points
if x0 == 1:
return sqrt(2)*sqrt((S.One - arg).as_leading_term(x))
if x0 in (-S.One, S.ComplexInfinity):
return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir)
# Handling points lying on branch cuts (-oo, -1) U (1, oo)
if (1 - x0**2).is_negative:
ndir = arg.dir(x, cdir if cdir else 1)
if im(ndir).is_negative:
if x0.is_negative:
return 2*pi - self.func(x0)
elif im(ndir).is_positive:
if x0.is_positive:
return -self.func(x0)
else:
return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir).expand()
return self.func(x0)
def _eval_is_extended_real(self):
x = self.args[0]
return x.is_extended_real and (1 - abs(x)).is_nonnegative
def _eval_is_nonnegative(self):
return self._eval_is_extended_real()
def _eval_nseries(self, x, n, logx, cdir=0): # acos
from sympy.series.order import O
arg0 = self.args[0].subs(x, 0)
# Handling branch points
if arg0 is S.One:
t = Dummy('t', positive=True)
ser = acos(S.One - t**2).rewrite(log).nseries(t, 0, 2*n)
arg1 = S.One - self.args[0]
f = arg1.as_leading_term(x)
g = (arg1 - f)/ f
if not g.is_meromorphic(x, 0): # cannot be expanded
return O(1) if n == 0 else O(sqrt(x))
res1 = sqrt(S.One + g)._eval_nseries(x, n=n, logx=logx)
res = (res1.removeO()*sqrt(f)).expand()
return ser.removeO().subs(t, res).expand().powsimp() + O(x**n, x)
if arg0 is S.NegativeOne:
t = Dummy('t', positive=True)
ser = acos(S.NegativeOne + t**2).rewrite(log).nseries(t, 0, 2*n)
arg1 = S.One + self.args[0]
f = arg1.as_leading_term(x)
g = (arg1 - f)/ f
if not g.is_meromorphic(x, 0): # cannot be expanded
return O(1) if n == 0 else pi + O(sqrt(x))
res1 = sqrt(S.One + g)._eval_nseries(x, n=n, logx=logx)
res = (res1.removeO()*sqrt(f)).expand()
return ser.removeO().subs(t, res).expand().powsimp() + O(x**n, x)
res = Function._eval_nseries(self, x, n=n, logx=logx)
if arg0 is S.ComplexInfinity:
return res
# Handling points lying on branch cuts (-oo, -1) U (1, oo)
if (1 - arg0**2).is_negative:
ndir = self.args[0].dir(x, cdir if cdir else 1)
if im(ndir).is_negative:
if arg0.is_negative:
return 2*pi - res
elif im(ndir).is_positive:
if arg0.is_positive:
return -res
else:
return self.rewrite(log)._eval_nseries(x, n, logx=logx, cdir=cdir)
return res
def _eval_rewrite_as_log(self, x, **kwargs):
return pi/2 + S.ImaginaryUnit*\
log(S.ImaginaryUnit*x + sqrt(1 - x**2))
_eval_rewrite_as_tractable = _eval_rewrite_as_log
def _eval_rewrite_as_asin(self, x, **kwargs):
return pi/2 - asin(x)
def _eval_rewrite_as_atan(self, x, **kwargs):
return atan(sqrt(1 - x**2)/x) + (pi/2)*(1 - x*sqrt(1/x**2))
def inverse(self, argindex=1):
"""
Returns the inverse of this function.
"""
return cos
def _eval_rewrite_as_acot(self, arg, **kwargs):
return pi/2 - 2*acot((1 + sqrt(1 - arg**2))/arg)
def _eval_rewrite_as_asec(self, arg, **kwargs):
return asec(1/arg)
def _eval_rewrite_as_acsc(self, arg, **kwargs):
return pi/2 - acsc(1/arg)
def _eval_conjugate(self):
z = self.args[0]
r = self.func(self.args[0].conjugate())
if z.is_extended_real is False:
return r
elif z.is_extended_real and (z + 1).is_nonnegative and (z - 1).is_nonpositive:
return r
class atan(InverseTrigonometricFunction):
r"""
The inverse tangent function.
Returns the arc tangent of x (measured in radians).
Explanation
===========
``atan(x)`` will evaluate automatically in the cases
$x \in \{\infty, -\infty, 0, 1, -1\}$ and for some instances when the
result is a rational multiple of $\pi$ (see the eval class method).
Examples
========
>>> from sympy import atan, oo
>>> atan(0)
0
>>> atan(1)
pi/4
>>> atan(oo)
pi/2
See Also
========
sin, csc, cos, sec, tan, cot
asin, acsc, acos, asec, acot, atan2
References
==========
.. [1] https://en.wikipedia.org/wiki/Inverse_trigonometric_functions
.. [2] https://dlmf.nist.gov/4.23
.. [3] https://functions.wolfram.com/ElementaryFunctions/ArcTan
"""
args: tTuple[Expr]
_singularities = (S.ImaginaryUnit, -S.ImaginaryUnit)
def fdiff(self, argindex=1):
if argindex == 1:
return 1/(1 + self.args[0]**2)
else:
raise ArgumentIndexError(self, argindex)
def _eval_is_rational(self):
s = self.func(*self.args)
if s.func == self.func:
if s.args[0].is_rational:
return False
else:
return s.is_rational
def _eval_is_positive(self):
return self.args[0].is_extended_positive
def _eval_is_nonnegative(self):
return self.args[0].is_extended_nonnegative
def _eval_is_zero(self):
return self.args[0].is_zero
def _eval_is_real(self):
return self.args[0].is_extended_real
@classmethod
def eval(cls, arg):
if arg.is_Number:
if arg is S.NaN:
return S.NaN
elif arg is S.Infinity:
return pi/2
elif arg is S.NegativeInfinity:
return -pi/2
elif arg.is_zero:
return S.Zero
elif arg is S.One:
return pi/4
elif arg is S.NegativeOne:
return -pi/4
if arg is S.ComplexInfinity:
from sympy.calculus.accumulationbounds import AccumBounds
return AccumBounds(-pi/2, pi/2)
if arg.could_extract_minus_sign():
return -cls(-arg)
if arg.is_number:
atan_table = cls._atan_table()
if arg in atan_table:
return atan_table[arg]
i_coeff = _imaginary_unit_as_coefficient(arg)
if i_coeff is not None:
from sympy.functions.elementary.hyperbolic import atanh
return S.ImaginaryUnit*atanh(i_coeff)
if arg.is_zero:
return S.Zero
if isinstance(arg, tan):
ang = arg.args[0]
if ang.is_comparable:
ang %= pi # restrict to [0,pi)
if ang > pi/2: # restrict to [-pi/2,pi/2]
ang -= pi
return ang
if isinstance(arg, cot): # atan(x) + acot(x) = pi/2
ang = arg.args[0]
if ang.is_comparable:
ang = pi/2 - acot(arg)
if ang > pi/2: # restrict to [-pi/2,pi/2]
ang -= pi
return ang
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
if n < 0 or n % 2 == 0:
return S.Zero
else:
x = sympify(x)
return S.NegativeOne**((n - 1)//2)*x**n/n
def _eval_as_leading_term(self, x, logx=None, cdir=0): # atan
arg = self.args[0]
x0 = arg.subs(x, 0).cancel()
if x0 is S.NaN:
return self.func(arg.as_leading_term(x))
if x0.is_zero:
return arg.as_leading_term(x)
# Handling branch points
if x0 in (-S.ImaginaryUnit, S.ImaginaryUnit, S.ComplexInfinity):
return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir).expand()
# Handling points lying on branch cuts (-I*oo, -I) U (I, I*oo)
if (1 + x0**2).is_negative:
ndir = arg.dir(x, cdir if cdir else 1)
if re(ndir).is_negative:
if im(x0).is_positive:
return self.func(x0) - pi
elif re(ndir).is_positive:
if im(x0).is_negative:
return self.func(x0) + pi
else:
return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir).expand()
return self.func(x0)
def _eval_nseries(self, x, n, logx, cdir=0): # atan
arg0 = self.args[0].subs(x, 0)
# Handling branch points
if arg0 in (S.ImaginaryUnit, S.NegativeOne*S.ImaginaryUnit):
return self.rewrite(log)._eval_nseries(x, n, logx=logx, cdir=cdir)
res = Function._eval_nseries(self, x, n=n, logx=logx)
ndir = self.args[0].dir(x, cdir if cdir else 1)
if arg0 is S.ComplexInfinity:
if re(ndir) > 0:
return res - pi
return res
# Handling points lying on branch cuts (-I*oo, -I) U (I, I*oo)
if (1 + arg0**2).is_negative:
if re(ndir).is_negative:
if im(arg0).is_positive:
return res - pi
elif re(ndir).is_positive:
if im(arg0).is_negative:
return res + pi
else:
return self.rewrite(log)._eval_nseries(x, n, logx=logx, cdir=cdir)
return res
def _eval_rewrite_as_log(self, x, **kwargs):
return S.ImaginaryUnit/2*(log(S.One - S.ImaginaryUnit*x)
- log(S.One + S.ImaginaryUnit*x))
_eval_rewrite_as_tractable = _eval_rewrite_as_log
def _eval_aseries(self, n, args0, x, logx):
if args0[0] in [S.Infinity, S.NegativeInfinity]:
return (pi/2 - atan(1/self.args[0]))._eval_nseries(x, n, logx)
else:
return super()._eval_aseries(n, args0, x, logx)
def inverse(self, argindex=1):
"""
Returns the inverse of this function.
"""
return tan
def _eval_rewrite_as_asin(self, arg, **kwargs):
return sqrt(arg**2)/arg*(pi/2 - asin(1/sqrt(1 + arg**2)))
def _eval_rewrite_as_acos(self, arg, **kwargs):
return sqrt(arg**2)/arg*acos(1/sqrt(1 + arg**2))
def _eval_rewrite_as_acot(self, arg, **kwargs):
return acot(1/arg)
def _eval_rewrite_as_asec(self, arg, **kwargs):
return sqrt(arg**2)/arg*asec(sqrt(1 + arg**2))
def _eval_rewrite_as_acsc(self, arg, **kwargs):
return sqrt(arg**2)/arg*(pi/2 - acsc(sqrt(1 + arg**2)))
class acot(InverseTrigonometricFunction):
r"""
The inverse cotangent function.
Returns the arc cotangent of x (measured in radians).
Explanation
===========
``acot(x)`` will evaluate automatically in the cases
$x \in \{\infty, -\infty, \tilde{\infty}, 0, 1, -1\}$
and for some instances when the result is a rational multiple of $\pi$
(see the eval class method).
A purely imaginary argument will lead to an ``acoth`` expression.
``acot(x)`` has a branch cut along $(-i, i)$, hence it is discontinuous
at 0. Its range for real $x$ is $(-\frac{\pi}{2}, \frac{\pi}{2}]$.
Examples
========
>>> from sympy import acot, sqrt
>>> acot(0)
pi/2
>>> acot(1)
pi/4
>>> acot(sqrt(3) - 2)
-5*pi/12
See Also
========
sin, csc, cos, sec, tan, cot
asin, acsc, acos, asec, atan, atan2
References
==========
.. [1] https://dlmf.nist.gov/4.23
.. [2] https://functions.wolfram.com/ElementaryFunctions/ArcCot
"""
_singularities = (S.ImaginaryUnit, -S.ImaginaryUnit)
def fdiff(self, argindex=1):
if argindex == 1:
return -1/(1 + self.args[0]**2)
else:
raise ArgumentIndexError(self, argindex)
def _eval_is_rational(self):
s = self.func(*self.args)
if s.func == self.func:
if s.args[0].is_rational:
return False
else:
return s.is_rational
def _eval_is_positive(self):
return self.args[0].is_nonnegative
def _eval_is_negative(self):
return self.args[0].is_negative
def _eval_is_extended_real(self):
return self.args[0].is_extended_real
@classmethod
def eval(cls, arg):
if arg.is_Number:
if arg is S.NaN:
return S.NaN
elif arg is S.Infinity:
return S.Zero
elif arg is S.NegativeInfinity:
return S.Zero
elif arg.is_zero:
return pi/ 2
elif arg is S.One:
return pi/4
elif arg is S.NegativeOne:
return -pi/4
if arg is S.ComplexInfinity:
return S.Zero
if arg.could_extract_minus_sign():
return -cls(-arg)
if arg.is_number:
atan_table = cls._atan_table()
if arg in atan_table:
ang = pi/2 - atan_table[arg]
if ang > pi/2: # restrict to (-pi/2,pi/2]
ang -= pi
return ang
i_coeff = _imaginary_unit_as_coefficient(arg)
if i_coeff is not None:
from sympy.functions.elementary.hyperbolic import acoth
return -S.ImaginaryUnit*acoth(i_coeff)
if arg.is_zero:
return pi*S.Half
if isinstance(arg, cot):
ang = arg.args[0]
if ang.is_comparable:
ang %= pi # restrict to [0,pi)
if ang > pi/2: # restrict to (-pi/2,pi/2]
ang -= pi;
return ang
if isinstance(arg, tan): # atan(x) + acot(x) = pi/2
ang = arg.args[0]
if ang.is_comparable:
ang = pi/2 - atan(arg)
if ang > pi/2: # restrict to (-pi/2,pi/2]
ang -= pi
return ang
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
if n == 0:
return pi/2 # FIX THIS
elif n < 0 or n % 2 == 0:
return S.Zero
else:
x = sympify(x)
return S.NegativeOne**((n + 1)//2)*x**n/n
def _eval_as_leading_term(self, x, logx=None, cdir=0): # acot
arg = self.args[0]
x0 = arg.subs(x, 0).cancel()
if x0 is S.NaN:
return self.func(arg.as_leading_term(x))
if x0 is S.ComplexInfinity:
return (1/arg).as_leading_term(x)
# Handling branch points
if x0 in (-S.ImaginaryUnit, S.ImaginaryUnit, S.Zero):
return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir).expand()
# Handling points lying on branch cuts [-I, I]
if x0.is_imaginary and (1 + x0**2).is_positive:
ndir = arg.dir(x, cdir if cdir else 1)
if re(ndir).is_positive:
if im(x0).is_positive:
return self.func(x0) + pi
elif re(ndir).is_negative:
if im(x0).is_negative:
return self.func(x0) - pi
else:
return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir).expand()
return self.func(x0)
def _eval_nseries(self, x, n, logx, cdir=0): # acot
arg0 = self.args[0].subs(x, 0)
# Handling branch points
if arg0 in (S.ImaginaryUnit, S.NegativeOne*S.ImaginaryUnit):
return self.rewrite(log)._eval_nseries(x, n, logx=logx, cdir=cdir)
res = Function._eval_nseries(self, x, n=n, logx=logx)
if arg0 is S.ComplexInfinity:
return res
ndir = self.args[0].dir(x, cdir if cdir else 1)
if arg0.is_zero:
if re(ndir) < 0:
return res - pi
return res
# Handling points lying on branch cuts [-I, I]
if arg0.is_imaginary and (1 + arg0**2).is_positive:
if re(ndir).is_positive:
if im(arg0).is_positive:
return res + pi
elif re(ndir).is_negative:
if im(arg0).is_negative:
return res - pi
else:
return self.rewrite(log)._eval_nseries(x, n, logx=logx, cdir=cdir)
return res
def _eval_aseries(self, n, args0, x, logx):
if args0[0] in [S.Infinity, S.NegativeInfinity]:
return atan(1/self.args[0])._eval_nseries(x, n, logx)
else:
return super()._eval_aseries(n, args0, x, logx)
def _eval_rewrite_as_log(self, x, **kwargs):
return S.ImaginaryUnit/2*(log(1 - S.ImaginaryUnit/x)
- log(1 + S.ImaginaryUnit/x))
_eval_rewrite_as_tractable = _eval_rewrite_as_log
def inverse(self, argindex=1):
"""
Returns the inverse of this function.
"""
return cot
def _eval_rewrite_as_asin(self, arg, **kwargs):
return (arg*sqrt(1/arg**2)*
(pi/2 - asin(sqrt(-arg**2)/sqrt(-arg**2 - 1))))
def _eval_rewrite_as_acos(self, arg, **kwargs):
return arg*sqrt(1/arg**2)*acos(sqrt(-arg**2)/sqrt(-arg**2 - 1))
def _eval_rewrite_as_atan(self, arg, **kwargs):
return atan(1/arg)
def _eval_rewrite_as_asec(self, arg, **kwargs):
return arg*sqrt(1/arg**2)*asec(sqrt((1 + arg**2)/arg**2))
def _eval_rewrite_as_acsc(self, arg, **kwargs):
return arg*sqrt(1/arg**2)*(pi/2 - acsc(sqrt((1 + arg**2)/arg**2)))
class asec(InverseTrigonometricFunction):
r"""
The inverse secant function.
Returns the arc secant of x (measured in radians).
Explanation
===========
``asec(x)`` will evaluate automatically in the cases
$x \in \{\infty, -\infty, 0, 1, -1\}$ and for some instances when the
result is a rational multiple of $\pi$ (see the eval class method).
``asec(x)`` has branch cut in the interval $[-1, 1]$. For complex arguments,
it can be defined [4]_ as
.. math::
\operatorname{sec^{-1}}(z) = -i\frac{\log\left(\sqrt{1 - z^2} + 1\right)}{z}
At ``x = 0``, for positive branch cut, the limit evaluates to ``zoo``. For
negative branch cut, the limit
.. math::
\lim_{z \to 0}-i\frac{\log\left(-\sqrt{1 - z^2} + 1\right)}{z}
simplifies to :math:`-i\log\left(z/2 + O\left(z^3\right)\right)` which
ultimately evaluates to ``zoo``.
As ``acos(x) = asec(1/x)``, a similar argument can be given for
``acos(x)``.
Examples
========
>>> from sympy import asec, oo
>>> asec(1)
0
>>> asec(-1)
pi
>>> asec(0)
zoo
>>> asec(-oo)
pi/2
See Also
========
sin, csc, cos, sec, tan, cot
asin, acsc, acos, atan, acot, atan2
References
==========
.. [1] https://en.wikipedia.org/wiki/Inverse_trigonometric_functions
.. [2] https://dlmf.nist.gov/4.23
.. [3] https://functions.wolfram.com/ElementaryFunctions/ArcSec
.. [4] https://reference.wolfram.com/language/ref/ArcSec.html
"""
@classmethod
def eval(cls, arg):
if arg.is_zero:
return S.ComplexInfinity
if arg.is_Number:
if arg is S.NaN:
return S.NaN
elif arg is S.One:
return S.Zero
elif arg is S.NegativeOne:
return pi
if arg in [S.Infinity, S.NegativeInfinity, S.ComplexInfinity]:
return pi/2
if arg.is_number:
acsc_table = cls._acsc_table()
if arg in acsc_table:
return pi/2 - acsc_table[arg]
elif -arg in acsc_table:
return pi/2 + acsc_table[-arg]
if arg.is_infinite:
return pi/2
if isinstance(arg, sec):
ang = arg.args[0]
if ang.is_comparable:
ang %= 2*pi # restrict to [0,2*pi)
if ang > pi: # restrict to [0,pi]
ang = 2*pi - ang
return ang
if isinstance(arg, csc): # asec(x) + acsc(x) = pi/2
ang = arg.args[0]
if ang.is_comparable:
return pi/2 - acsc(arg)
def fdiff(self, argindex=1):
if argindex == 1:
return 1/(self.args[0]**2*sqrt(1 - 1/self.args[0]**2))
else:
raise ArgumentIndexError(self, argindex)
def inverse(self, argindex=1):
"""
Returns the inverse of this function.
"""
return sec
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
if n == 0:
return S.ImaginaryUnit*log(2 / x)
elif n < 0 or n % 2 == 1:
return S.Zero
else:
x = sympify(x)
if len(previous_terms) > 2 and n > 2:
p = previous_terms[-2]
return p * ((n - 1)*(n-2)) * x**2/(4 * (n//2)**2)
else:
k = n // 2
R = RisingFactorial(S.Half, k) * n
F = factorial(k) * n // 2 * n // 2
return -S.ImaginaryUnit * R / F * x**n / 4
def _eval_as_leading_term(self, x, logx=None, cdir=0): # asec
arg = self.args[0]
x0 = arg.subs(x, 0).cancel()
if x0 is S.NaN:
return self.func(arg.as_leading_term(x))
# Handling branch points
if x0 == 1:
return sqrt(2)*sqrt((arg - S.One).as_leading_term(x))
if x0 in (-S.One, S.Zero):
return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir)
# Handling points lying on branch cuts (-1, 1)
if x0.is_real and (1 - x0**2).is_positive:
ndir = arg.dir(x, cdir if cdir else 1)
if im(ndir).is_negative:
if x0.is_positive:
return -self.func(x0)
elif im(ndir).is_positive:
if x0.is_negative:
return 2*pi - self.func(x0)
else:
return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir).expand()
return self.func(x0)
def _eval_nseries(self, x, n, logx, cdir=0): # asec
from sympy.series.order import O
arg0 = self.args[0].subs(x, 0)
# Handling branch points
if arg0 is S.One:
t = Dummy('t', positive=True)
ser = asec(S.One + t**2).rewrite(log).nseries(t, 0, 2*n)
arg1 = S.NegativeOne + self.args[0]
f = arg1.as_leading_term(x)
g = (arg1 - f)/ f
res1 = sqrt(S.One + g)._eval_nseries(x, n=n, logx=logx)
res = (res1.removeO()*sqrt(f)).expand()
return ser.removeO().subs(t, res).expand().powsimp() + O(x**n, x)
if arg0 is S.NegativeOne:
t = Dummy('t', positive=True)
ser = asec(S.NegativeOne - t**2).rewrite(log).nseries(t, 0, 2*n)
arg1 = S.NegativeOne - self.args[0]
f = arg1.as_leading_term(x)
g = (arg1 - f)/ f
res1 = sqrt(S.One + g)._eval_nseries(x, n=n, logx=logx)
res = (res1.removeO()*sqrt(f)).expand()
return ser.removeO().subs(t, res).expand().powsimp() + O(x**n, x)
res = Function._eval_nseries(self, x, n=n, logx=logx)
if arg0 is S.ComplexInfinity:
return res
# Handling points lying on branch cuts (-1, 1)
if arg0.is_real and (1 - arg0**2).is_positive:
ndir = self.args[0].dir(x, cdir if cdir else 1)
if im(ndir).is_negative:
if arg0.is_positive:
return -res
elif im(ndir).is_positive:
if arg0.is_negative:
return 2*pi - res
else:
return self.rewrite(log)._eval_nseries(x, n, logx=logx, cdir=cdir)
return res
def _eval_is_extended_real(self):
x = self.args[0]
if x.is_extended_real is False:
return False
return fuzzy_or(((x - 1).is_nonnegative, (-x - 1).is_nonnegative))
def _eval_rewrite_as_log(self, arg, **kwargs):
return pi/2 + S.ImaginaryUnit*log(S.ImaginaryUnit/arg + sqrt(1 - 1/arg**2))
_eval_rewrite_as_tractable = _eval_rewrite_as_log
def _eval_rewrite_as_asin(self, arg, **kwargs):
return pi/2 - asin(1/arg)
def _eval_rewrite_as_acos(self, arg, **kwargs):
return acos(1/arg)
def _eval_rewrite_as_atan(self, x, **kwargs):
sx2x = sqrt(x**2)/x
return pi/2*(1 - sx2x) + sx2x*atan(sqrt(x**2 - 1))
def _eval_rewrite_as_acot(self, x, **kwargs):
sx2x = sqrt(x**2)/x
return pi/2*(1 - sx2x) + sx2x*acot(1/sqrt(x**2 - 1))
def _eval_rewrite_as_acsc(self, arg, **kwargs):
return pi/2 - acsc(arg)
class acsc(InverseTrigonometricFunction):
r"""
The inverse cosecant function.
Returns the arc cosecant of x (measured in radians).
Explanation
===========
``acsc(x)`` will evaluate automatically in the cases
$x \in \{\infty, -\infty, 0, 1, -1\}$` and for some instances when the
result is a rational multiple of $\pi$ (see the ``eval`` class method).
Examples
========
>>> from sympy import acsc, oo
>>> acsc(1)
pi/2
>>> acsc(-1)
-pi/2
>>> acsc(oo)
0
>>> acsc(-oo) == acsc(oo)
True
>>> acsc(0)
zoo
See Also
========
sin, csc, cos, sec, tan, cot
asin, acos, asec, atan, acot, atan2
References
==========
.. [1] https://en.wikipedia.org/wiki/Inverse_trigonometric_functions
.. [2] https://dlmf.nist.gov/4.23
.. [3] https://functions.wolfram.com/ElementaryFunctions/ArcCsc
"""
@classmethod
def eval(cls, arg):
if arg.is_zero:
return S.ComplexInfinity
if arg.is_Number:
if arg is S.NaN:
return S.NaN
elif arg is S.One:
return pi/2
elif arg is S.NegativeOne:
return -pi/2
if arg in [S.Infinity, S.NegativeInfinity, S.ComplexInfinity]:
return S.Zero
if arg.could_extract_minus_sign():
return -cls(-arg)
if arg.is_infinite:
return S.Zero
if arg.is_number:
acsc_table = cls._acsc_table()
if arg in acsc_table:
return acsc_table[arg]
if isinstance(arg, csc):
ang = arg.args[0]
if ang.is_comparable:
ang %= 2*pi # restrict to [0,2*pi)
if ang > pi: # restrict to (-pi,pi]
ang = pi - ang
# restrict to [-pi/2,pi/2]
if ang > pi/2:
ang = pi - ang
if ang < -pi/2:
ang = -pi - ang
return ang
if isinstance(arg, sec): # asec(x) + acsc(x) = pi/2
ang = arg.args[0]
if ang.is_comparable:
return pi/2 - asec(arg)
def fdiff(self, argindex=1):
if argindex == 1:
return -1/(self.args[0]**2*sqrt(1 - 1/self.args[0]**2))
else:
raise ArgumentIndexError(self, argindex)
def inverse(self, argindex=1):
"""
Returns the inverse of this function.
"""
return csc
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
if n == 0:
return pi/2 - S.ImaginaryUnit*log(2) + S.ImaginaryUnit*log(x)
elif n < 0 or n % 2 == 1:
return S.Zero
else:
x = sympify(x)
if len(previous_terms) > 2 and n > 2:
p = previous_terms[-2]
return p * ((n - 1)*(n-2)) * x**2/(4 * (n//2)**2)
else:
k = n // 2
R = RisingFactorial(S.Half, k) * n
F = factorial(k) * n // 2 * n // 2
return S.ImaginaryUnit * R / F * x**n / 4
def _eval_as_leading_term(self, x, logx=None, cdir=0): # acsc
arg = self.args[0]
x0 = arg.subs(x, 0).cancel()
if x0 is S.NaN:
return self.func(arg.as_leading_term(x))
# Handling branch points
if x0 in (-S.One, S.One, S.Zero):
return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir).expand()
if x0 is S.ComplexInfinity:
return (1/arg).as_leading_term(x)
# Handling points lying on branch cuts (-1, 1)
if x0.is_real and (1 - x0**2).is_positive:
ndir = arg.dir(x, cdir if cdir else 1)
if im(ndir).is_negative:
if x0.is_positive:
return pi - self.func(x0)
elif im(ndir).is_positive:
if x0.is_negative:
return -pi - self.func(x0)
else:
return self.rewrite(log)._eval_as_leading_term(x, logx=logx, cdir=cdir).expand()
return self.func(x0)
def _eval_nseries(self, x, n, logx, cdir=0): # acsc
from sympy.series.order import O
arg0 = self.args[0].subs(x, 0)
# Handling branch points
if arg0 is S.One:
t = Dummy('t', positive=True)
ser = acsc(S.One + t**2).rewrite(log).nseries(t, 0, 2*n)
arg1 = S.NegativeOne + self.args[0]
f = arg1.as_leading_term(x)
g = (arg1 - f)/ f
res1 = sqrt(S.One + g)._eval_nseries(x, n=n, logx=logx)
res = (res1.removeO()*sqrt(f)).expand()
return ser.removeO().subs(t, res).expand().powsimp() + O(x**n, x)
if arg0 is S.NegativeOne:
t = Dummy('t', positive=True)
ser = acsc(S.NegativeOne - t**2).rewrite(log).nseries(t, 0, 2*n)
arg1 = S.NegativeOne - self.args[0]
f = arg1.as_leading_term(x)
g = (arg1 - f)/ f
res1 = sqrt(S.One + g)._eval_nseries(x, n=n, logx=logx)
res = (res1.removeO()*sqrt(f)).expand()
return ser.removeO().subs(t, res).expand().powsimp() + O(x**n, x)
res = Function._eval_nseries(self, x, n=n, logx=logx)
if arg0 is S.ComplexInfinity:
return res
# Handling points lying on branch cuts (-1, 1)
if arg0.is_real and (1 - arg0**2).is_positive:
ndir = self.args[0].dir(x, cdir if cdir else 1)
if im(ndir).is_negative:
if arg0.is_positive:
return pi - res
elif im(ndir).is_positive:
if arg0.is_negative:
return -pi - res
else:
return self.rewrite(log)._eval_nseries(x, n, logx=logx, cdir=cdir)
return res
def _eval_rewrite_as_log(self, arg, **kwargs):
return -S.ImaginaryUnit*log(S.ImaginaryUnit/arg + sqrt(1 - 1/arg**2))
_eval_rewrite_as_tractable = _eval_rewrite_as_log
def _eval_rewrite_as_asin(self, arg, **kwargs):
return asin(1/arg)
def _eval_rewrite_as_acos(self, arg, **kwargs):
return pi/2 - acos(1/arg)
def _eval_rewrite_as_atan(self, x, **kwargs):
return sqrt(x**2)/x*(pi/2 - atan(sqrt(x**2 - 1)))
def _eval_rewrite_as_acot(self, arg, **kwargs):
return sqrt(arg**2)/arg*(pi/2 - acot(1/sqrt(arg**2 - 1)))
def _eval_rewrite_as_asec(self, arg, **kwargs):
return pi/2 - asec(arg)
class atan2(InverseTrigonometricFunction):
r"""
The function ``atan2(y, x)`` computes `\operatorname{atan}(y/x)` taking
two arguments `y` and `x`. Signs of both `y` and `x` are considered to
determine the appropriate quadrant of `\operatorname{atan}(y/x)`.
The range is `(-\pi, \pi]`. The complete definition reads as follows:
.. math::
\operatorname{atan2}(y, x) =
\begin{cases}
\arctan\left(\frac y x\right) & \qquad x > 0 \\
\arctan\left(\frac y x\right) + \pi& \qquad y \ge 0, x < 0 \\
\arctan\left(\frac y x\right) - \pi& \qquad y < 0, x < 0 \\
+\frac{\pi}{2} & \qquad y > 0, x = 0 \\
-\frac{\pi}{2} & \qquad y < 0, x = 0 \\
\text{undefined} & \qquad y = 0, x = 0
\end{cases}
Attention: Note the role reversal of both arguments. The `y`-coordinate
is the first argument and the `x`-coordinate the second.
If either `x` or `y` is complex:
.. math::
\operatorname{atan2}(y, x) =
-i\log\left(\frac{x + iy}{\sqrt{x^2 + y^2}}\right)
Examples
========
Going counter-clock wise around the origin we find the
following angles:
>>> from sympy import atan2
>>> atan2(0, 1)
0
>>> atan2(1, 1)
pi/4
>>> atan2(1, 0)
pi/2
>>> atan2(1, -1)
3*pi/4
>>> atan2(0, -1)
pi
>>> atan2(-1, -1)
-3*pi/4
>>> atan2(-1, 0)
-pi/2
>>> atan2(-1, 1)
-pi/4
which are all correct. Compare this to the results of the ordinary
`\operatorname{atan}` function for the point `(x, y) = (-1, 1)`
>>> from sympy import atan, S
>>> atan(S(1)/-1)
-pi/4
>>> atan2(1, -1)
3*pi/4
where only the `\operatorname{atan2}` function reurns what we expect.
We can differentiate the function with respect to both arguments:
>>> from sympy import diff
>>> from sympy.abc import x, y
>>> diff(atan2(y, x), x)
-y/(x**2 + y**2)
>>> diff(atan2(y, x), y)
x/(x**2 + y**2)
We can express the `\operatorname{atan2}` function in terms of
complex logarithms:
>>> from sympy import log
>>> atan2(y, x).rewrite(log)
-I*log((x + I*y)/sqrt(x**2 + y**2))
and in terms of `\operatorname(atan)`:
>>> from sympy import atan
>>> atan2(y, x).rewrite(atan)
Piecewise((2*atan(y/(x + sqrt(x**2 + y**2))), Ne(y, 0)), (pi, re(x) < 0), (0, Ne(x, 0)), (nan, True))
but note that this form is undefined on the negative real axis.
See Also
========
sin, csc, cos, sec, tan, cot
asin, acsc, acos, asec, atan, acot
References
==========
.. [1] https://en.wikipedia.org/wiki/Inverse_trigonometric_functions
.. [2] https://en.wikipedia.org/wiki/Atan2
.. [3] https://functions.wolfram.com/ElementaryFunctions/ArcTan2
"""
@classmethod
def eval(cls, y, x):
from sympy.functions.special.delta_functions import Heaviside
if x is S.NegativeInfinity:
if y.is_zero:
# Special case y = 0 because we define Heaviside(0) = 1/2
return pi
return 2*pi*(Heaviside(re(y))) - pi
elif x is S.Infinity:
return S.Zero
elif x.is_imaginary and y.is_imaginary and x.is_number and y.is_number:
x = im(x)
y = im(y)
if x.is_extended_real and y.is_extended_real:
if x.is_positive:
return atan(y/x)
elif x.is_negative:
if y.is_negative:
return atan(y/x) - pi
elif y.is_nonnegative:
return atan(y/x) + pi
elif x.is_zero:
if y.is_positive:
return pi/2
elif y.is_negative:
return -pi/2
elif y.is_zero:
return S.NaN
if y.is_zero:
if x.is_extended_nonzero:
return pi*(S.One - Heaviside(x))
if x.is_number:
return Piecewise((pi, re(x) < 0),
(0, Ne(x, 0)),
(S.NaN, True))
if x.is_number and y.is_number:
return -S.ImaginaryUnit*log(
(x + S.ImaginaryUnit*y)/sqrt(x**2 + y**2))
def _eval_rewrite_as_log(self, y, x, **kwargs):
return -S.ImaginaryUnit*log((x + S.ImaginaryUnit*y)/sqrt(x**2 + y**2))
def _eval_rewrite_as_atan(self, y, x, **kwargs):
return Piecewise((2*atan(y/(x + sqrt(x**2 + y**2))), Ne(y, 0)),
(pi, re(x) < 0),
(0, Ne(x, 0)),
(S.NaN, True))
def _eval_rewrite_as_arg(self, y, x, **kwargs):
if x.is_extended_real and y.is_extended_real:
return arg_f(x + y*S.ImaginaryUnit)
n = x + S.ImaginaryUnit*y
d = x**2 + y**2
return arg_f(n/sqrt(d)) - S.ImaginaryUnit*log(abs(n)/sqrt(abs(d)))
def _eval_is_extended_real(self):
return self.args[0].is_extended_real and self.args[1].is_extended_real
def _eval_conjugate(self):
return self.func(self.args[0].conjugate(), self.args[1].conjugate())
def fdiff(self, argindex):
y, x = self.args
if argindex == 1:
# Diff wrt y
return x/(x**2 + y**2)
elif argindex == 2:
# Diff wrt x
return -y/(x**2 + y**2)
else:
raise ArgumentIndexError(self, argindex)
def _eval_evalf(self, prec):
y, x = self.args
if x.is_extended_real and y.is_extended_real:
return super()._eval_evalf(prec)
PK ]ZZZ 1 sympy/functions/elementary/benchmarks/__init__.pyPK ]ZZZ�2W� � 2 sympy/functions/elementary/benchmarks/bench_exp.pyfrom sympy.core.symbol import symbols
from sympy.functions.elementary.exponential import exp
x, y = symbols('x,y')
e = exp(2*x)
q = exp(3*x)
def timeit_exp_subs():
e.subs(q, y)
PK ]ZZZ��H�; ; # sympy/functions/special/__init__.py# Stub __init__.py for the sympy.functions.special package
PK ]ZZZ�4�� �� ! sympy/functions/special/bessel.pyfrom functools import wraps
from sympy.core import S
from sympy.core.add import Add
from sympy.core.cache import cacheit
from sympy.core.expr import Expr
from sympy.core.function import Function, ArgumentIndexError, _mexpand
from sympy.core.logic import fuzzy_or, fuzzy_not
from sympy.core.numbers import Rational, pi, I
from sympy.core.power import Pow
from sympy.core.symbol import Dummy, uniquely_named_symbol, Wild
from sympy.core.sympify import sympify
from sympy.functions.combinatorial.factorials import factorial
from sympy.functions.elementary.trigonometric import sin, cos, csc, cot
from sympy.functions.elementary.integers import ceiling
from sympy.functions.elementary.exponential import exp, log
from sympy.functions.elementary.miscellaneous import cbrt, sqrt, root
from sympy.functions.elementary.complexes import (Abs, re, im, polar_lift, unpolarify)
from sympy.functions.special.gamma_functions import gamma, digamma, uppergamma
from sympy.functions.special.hyper import hyper
from sympy.polys.orthopolys import spherical_bessel_fn
from mpmath import mp, workprec
# TODO
# o Scorer functions G1 and G2
# o Asymptotic expansions
# These are possible, e.g. for fixed order, but since the bessel type
# functions are oscillatory they are not actually tractable at
# infinity, so this is not particularly useful right now.
# o Nicer series expansions.
# o More rewriting.
# o Add solvers to ode.py (or rather add solvers for the hypergeometric equation).
class BesselBase(Function):
"""
Abstract base class for Bessel-type functions.
This class is meant to reduce code duplication.
All Bessel-type functions can 1) be differentiated, with the derivatives
expressed in terms of similar functions, and 2) be rewritten in terms
of other Bessel-type functions.
Here, Bessel-type functions are assumed to have one complex parameter.
To use this base class, define class attributes ``_a`` and ``_b`` such that
``2*F_n' = -_a*F_{n+1} + b*F_{n-1}``.
"""
@property
def order(self):
""" The order of the Bessel-type function. """
return self.args[0]
@property
def argument(self):
""" The argument of the Bessel-type function. """
return self.args[1]
@classmethod
def eval(cls, nu, z):
return
def fdiff(self, argindex=2):
if argindex != 2:
raise ArgumentIndexError(self, argindex)
return (self._b/2 * self.__class__(self.order - 1, self.argument) -
self._a/2 * self.__class__(self.order + 1, self.argument))
def _eval_conjugate(self):
z = self.argument
if z.is_extended_negative is False:
return self.__class__(self.order.conjugate(), z.conjugate())
def _eval_is_meromorphic(self, x, a):
nu, z = self.order, self.argument
if nu.has(x):
return False
if not z._eval_is_meromorphic(x, a):
return None
z0 = z.subs(x, a)
if nu.is_integer:
if isinstance(self, (besselj, besseli, hn1, hn2, jn, yn)) or not nu.is_zero:
return fuzzy_not(z0.is_infinite)
return fuzzy_not(fuzzy_or([z0.is_zero, z0.is_infinite]))
def _eval_expand_func(self, **hints):
nu, z, f = self.order, self.argument, self.__class__
if nu.is_real:
if (nu - 1).is_positive:
return (-self._a*self._b*f(nu - 2, z)._eval_expand_func() +
2*self._a*(nu - 1)*f(nu - 1, z)._eval_expand_func()/z)
elif (nu + 1).is_negative:
return (2*self._b*(nu + 1)*f(nu + 1, z)._eval_expand_func()/z -
self._a*self._b*f(nu + 2, z)._eval_expand_func())
return self
def _eval_simplify(self, **kwargs):
from sympy.simplify.simplify import besselsimp
return besselsimp(self)
class besselj(BesselBase):
r"""
Bessel function of the first kind.
Explanation
===========
The Bessel $J$ function of order $\nu$ is defined to be the function
satisfying Bessel's differential equation
.. math ::
z^2 \frac{\mathrm{d}^2 w}{\mathrm{d}z^2}
+ z \frac{\mathrm{d}w}{\mathrm{d}z} + (z^2 - \nu^2) w = 0,
with Laurent expansion
.. math ::
J_\nu(z) = z^\nu \left(\frac{1}{\Gamma(\nu + 1) 2^\nu} + O(z^2) \right),
if $\nu$ is not a negative integer. If $\nu=-n \in \mathbb{Z}_{<0}$
*is* a negative integer, then the definition is
.. math ::
J_{-n}(z) = (-1)^n J_n(z).
Examples
========
Create a Bessel function object:
>>> from sympy import besselj, jn
>>> from sympy.abc import z, n
>>> b = besselj(n, z)
Differentiate it:
>>> b.diff(z)
besselj(n - 1, z)/2 - besselj(n + 1, z)/2
Rewrite in terms of spherical Bessel functions:
>>> b.rewrite(jn)
sqrt(2)*sqrt(z)*jn(n - 1/2, z)/sqrt(pi)
Access the parameter and argument:
>>> b.order
n
>>> b.argument
z
See Also
========
bessely, besseli, besselk
References
==========
.. [1] Abramowitz, Milton; Stegun, Irene A., eds. (1965), "Chapter 9",
Handbook of Mathematical Functions with Formulas, Graphs, and
Mathematical Tables
.. [2] Luke, Y. L. (1969), The Special Functions and Their
Approximations, Volume 1
.. [3] https://en.wikipedia.org/wiki/Bessel_function
.. [4] https://functions.wolfram.com/Bessel-TypeFunctions/BesselJ/
"""
_a = S.One
_b = S.One
@classmethod
def eval(cls, nu, z):
if z.is_zero:
if nu.is_zero:
return S.One
elif (nu.is_integer and nu.is_zero is False) or re(nu).is_positive:
return S.Zero
elif re(nu).is_negative and not (nu.is_integer is True):
return S.ComplexInfinity
elif nu.is_imaginary:
return S.NaN
if z in (S.Infinity, S.NegativeInfinity):
return S.Zero
if z.could_extract_minus_sign():
return (z)**nu*(-z)**(-nu)*besselj(nu, -z)
if nu.is_integer:
if nu.could_extract_minus_sign():
return S.NegativeOne**(-nu)*besselj(-nu, z)
newz = z.extract_multiplicatively(I)
if newz: # NOTE we don't want to change the function if z==0
return I**(nu)*besseli(nu, newz)
# branch handling:
if nu.is_integer:
newz = unpolarify(z)
if newz != z:
return besselj(nu, newz)
else:
newz, n = z.extract_branch_factor()
if n != 0:
return exp(2*n*pi*nu*I)*besselj(nu, newz)
nnu = unpolarify(nu)
if nu != nnu:
return besselj(nnu, z)
def _eval_rewrite_as_besseli(self, nu, z, **kwargs):
return exp(I*pi*nu/2)*besseli(nu, polar_lift(-I)*z)
def _eval_rewrite_as_bessely(self, nu, z, **kwargs):
if nu.is_integer is False:
return csc(pi*nu)*bessely(-nu, z) - cot(pi*nu)*bessely(nu, z)
def _eval_rewrite_as_jn(self, nu, z, **kwargs):
return sqrt(2*z/pi)*jn(nu - S.Half, self.argument)
def _eval_as_leading_term(self, x, logx=None, cdir=0):
nu, z = self.args
try:
arg = z.as_leading_term(x)
except NotImplementedError:
return self
c, e = arg.as_coeff_exponent(x)
if e.is_positive:
return arg**nu/(2**nu*gamma(nu + 1))
elif e.is_negative:
cdir = 1 if cdir == 0 else cdir
sign = c*cdir**e
if not sign.is_negative:
# Refer Abramowitz and Stegun 1965, p. 364 for more information on
# asymptotic approximation of besselj function.
return sqrt(2)*cos(z - pi*(2*nu + 1)/4)/sqrt(pi*z)
return self
return super(besselj, self)._eval_as_leading_term(x, logx, cdir)
def _eval_is_extended_real(self):
nu, z = self.args
if nu.is_integer and z.is_extended_real:
return True
def _eval_nseries(self, x, n, logx, cdir=0):
# Refer https://functions.wolfram.com/Bessel-TypeFunctions/BesselJ/06/01/04/01/01/0003/
# for more information on nseries expansion of besselj function.
from sympy.series.order import Order
nu, z = self.args
# In case of powers less than 1, number of terms need to be computed
# separately to avoid repeated callings of _eval_nseries with wrong n
try:
_, exp = z.leadterm(x)
except (ValueError, NotImplementedError):
return self
if exp.is_positive:
newn = ceiling(n/exp)
o = Order(x**n, x)
r = (z/2)._eval_nseries(x, n, logx, cdir).removeO()
if r is S.Zero:
return o
t = (_mexpand(r**2) + o).removeO()
term = r**nu/gamma(nu + 1)
s = [term]
for k in range(1, (newn + 1)//2):
term *= -t/(k*(nu + k))
term = (_mexpand(term) + o).removeO()
s.append(term)
return Add(*s) + o
return super(besselj, self)._eval_nseries(x, n, logx, cdir)
class bessely(BesselBase):
r"""
Bessel function of the second kind.
Explanation
===========
The Bessel $Y$ function of order $\nu$ is defined as
.. math ::
Y_\nu(z) = \lim_{\mu \to \nu} \frac{J_\mu(z) \cos(\pi \mu)
- J_{-\mu}(z)}{\sin(\pi \mu)},
where $J_\mu(z)$ is the Bessel function of the first kind.
It is a solution to Bessel's equation, and linearly independent from
$J_\nu$.
Examples
========
>>> from sympy import bessely, yn
>>> from sympy.abc import z, n
>>> b = bessely(n, z)
>>> b.diff(z)
bessely(n - 1, z)/2 - bessely(n + 1, z)/2
>>> b.rewrite(yn)
sqrt(2)*sqrt(z)*yn(n - 1/2, z)/sqrt(pi)
See Also
========
besselj, besseli, besselk
References
==========
.. [1] https://functions.wolfram.com/Bessel-TypeFunctions/BesselY/
"""
_a = S.One
_b = S.One
@classmethod
def eval(cls, nu, z):
if z.is_zero:
if nu.is_zero:
return S.NegativeInfinity
elif re(nu).is_zero is False:
return S.ComplexInfinity
elif re(nu).is_zero:
return S.NaN
if z in (S.Infinity, S.NegativeInfinity):
return S.Zero
if z == I*S.Infinity:
return exp(I*pi*(nu + 1)/2) * S.Infinity
if z == I*S.NegativeInfinity:
return exp(-I*pi*(nu + 1)/2) * S.Infinity
if nu.is_integer:
if nu.could_extract_minus_sign():
return S.NegativeOne**(-nu)*bessely(-nu, z)
def _eval_rewrite_as_besselj(self, nu, z, **kwargs):
if nu.is_integer is False:
return csc(pi*nu)*(cos(pi*nu)*besselj(nu, z) - besselj(-nu, z))
def _eval_rewrite_as_besseli(self, nu, z, **kwargs):
aj = self._eval_rewrite_as_besselj(*self.args)
if aj:
return aj.rewrite(besseli)
def _eval_rewrite_as_yn(self, nu, z, **kwargs):
return sqrt(2*z/pi) * yn(nu - S.Half, self.argument)
def _eval_as_leading_term(self, x, logx=None, cdir=0):
nu, z = self.args
try:
arg = z.as_leading_term(x)
except NotImplementedError:
return self
c, e = arg.as_coeff_exponent(x)
if e.is_positive:
term_one = ((2/pi)*log(z/2)*besselj(nu, z))
term_two = -(z/2)**(-nu)*factorial(nu - 1)/pi if (nu).is_positive else S.Zero
term_three = -(z/2)**nu/(pi*factorial(nu))*(digamma(nu + 1) - S.EulerGamma)
arg = Add(*[term_one, term_two, term_three]).as_leading_term(x, logx=logx)
return arg
elif e.is_negative:
cdir = 1 if cdir == 0 else cdir
sign = c*cdir**e
if not sign.is_negative:
# Refer Abramowitz and Stegun 1965, p. 364 for more information on
# asymptotic approximation of bessely function.
return sqrt(2)*(-sin(pi*nu/2 - z + pi/4) + 3*cos(pi*nu/2 - z + pi/4)/(8*z))*sqrt(1/z)/sqrt(pi)
return self
return super(bessely, self)._eval_as_leading_term(x, logx, cdir)
def _eval_is_extended_real(self):
nu, z = self.args
if nu.is_integer and z.is_positive:
return True
def _eval_nseries(self, x, n, logx, cdir=0):
# Refer https://functions.wolfram.com/Bessel-TypeFunctions/BesselY/06/01/04/01/02/0008/
# for more information on nseries expansion of bessely function.
from sympy.series.order import Order
nu, z = self.args
# In case of powers less than 1, number of terms need to be computed
# separately to avoid repeated callings of _eval_nseries with wrong n
try:
_, exp = z.leadterm(x)
except (ValueError, NotImplementedError):
return self
if exp.is_positive and nu.is_integer:
newn = ceiling(n/exp)
bn = besselj(nu, z)
a = ((2/pi)*log(z/2)*bn)._eval_nseries(x, n, logx, cdir)
b, c = [], []
o = Order(x**n, x)
r = (z/2)._eval_nseries(x, n, logx, cdir).removeO()
if r is S.Zero:
return o
t = (_mexpand(r**2) + o).removeO()
if nu > S.Zero:
term = r**(-nu)*factorial(nu - 1)/pi
b.append(term)
for k in range(1, nu):
denom = (nu - k)*k
if denom == S.Zero:
term *= t/k
else:
term *= t/denom
term = (_mexpand(term) + o).removeO()
b.append(term)
p = r**nu/(pi*factorial(nu))
term = p*(digamma(nu + 1) - S.EulerGamma)
c.append(term)
for k in range(1, (newn + 1)//2):
p *= -t/(k*(k + nu))
p = (_mexpand(p) + o).removeO()
term = p*(digamma(k + nu + 1) + digamma(k + 1))
c.append(term)
return a - Add(*b) - Add(*c) # Order term comes from a
return super(bessely, self)._eval_nseries(x, n, logx, cdir)
class besseli(BesselBase):
r"""
Modified Bessel function of the first kind.
Explanation
===========
The Bessel $I$ function is a solution to the modified Bessel equation
.. math ::
z^2 \frac{\mathrm{d}^2 w}{\mathrm{d}z^2}
+ z \frac{\mathrm{d}w}{\mathrm{d}z} + (z^2 + \nu^2)^2 w = 0.
It can be defined as
.. math ::
I_\nu(z) = i^{-\nu} J_\nu(iz),
where $J_\nu(z)$ is the Bessel function of the first kind.
Examples
========
>>> from sympy import besseli
>>> from sympy.abc import z, n
>>> besseli(n, z).diff(z)
besseli(n - 1, z)/2 + besseli(n + 1, z)/2
See Also
========
besselj, bessely, besselk
References
==========
.. [1] https://functions.wolfram.com/Bessel-TypeFunctions/BesselI/
"""
_a = -S.One
_b = S.One
@classmethod
def eval(cls, nu, z):
if z.is_zero:
if nu.is_zero:
return S.One
elif (nu.is_integer and nu.is_zero is False) or re(nu).is_positive:
return S.Zero
elif re(nu).is_negative and not (nu.is_integer is True):
return S.ComplexInfinity
elif nu.is_imaginary:
return S.NaN
if im(z) in (S.Infinity, S.NegativeInfinity):
return S.Zero
if z is S.Infinity:
return S.Infinity
if z is S.NegativeInfinity:
return (-1)**nu*S.Infinity
if z.could_extract_minus_sign():
return (z)**nu*(-z)**(-nu)*besseli(nu, -z)
if nu.is_integer:
if nu.could_extract_minus_sign():
return besseli(-nu, z)
newz = z.extract_multiplicatively(I)
if newz: # NOTE we don't want to change the function if z==0
return I**(-nu)*besselj(nu, -newz)
# branch handling:
if nu.is_integer:
newz = unpolarify(z)
if newz != z:
return besseli(nu, newz)
else:
newz, n = z.extract_branch_factor()
if n != 0:
return exp(2*n*pi*nu*I)*besseli(nu, newz)
nnu = unpolarify(nu)
if nu != nnu:
return besseli(nnu, z)
def _eval_rewrite_as_besselj(self, nu, z, **kwargs):
return exp(-I*pi*nu/2)*besselj(nu, polar_lift(I)*z)
def _eval_rewrite_as_bessely(self, nu, z, **kwargs):
aj = self._eval_rewrite_as_besselj(*self.args)
if aj:
return aj.rewrite(bessely)
def _eval_rewrite_as_jn(self, nu, z, **kwargs):
return self._eval_rewrite_as_besselj(*self.args).rewrite(jn)
def _eval_is_extended_real(self):
nu, z = self.args
if nu.is_integer and z.is_extended_real:
return True
def _eval_as_leading_term(self, x, logx=None, cdir=0):
nu, z = self.args
try:
arg = z.as_leading_term(x)
except NotImplementedError:
return self
c, e = arg.as_coeff_exponent(x)
if e.is_positive:
return arg**nu/(2**nu*gamma(nu + 1))
elif e.is_negative:
cdir = 1 if cdir == 0 else cdir
sign = c*cdir**e
if not sign.is_negative:
# Refer Abramowitz and Stegun 1965, p. 377 for more information on
# asymptotic approximation of besseli function.
return exp(z)/sqrt(2*pi*z)
return self
return super(besseli, self)._eval_as_leading_term(x, logx, cdir)
def _eval_nseries(self, x, n, logx, cdir=0):
# Refer https://functions.wolfram.com/Bessel-TypeFunctions/BesselI/06/01/04/01/01/0003/
# for more information on nseries expansion of besseli function.
from sympy.series.order import Order
nu, z = self.args
# In case of powers less than 1, number of terms need to be computed
# separately to avoid repeated callings of _eval_nseries with wrong n
try:
_, exp = z.leadterm(x)
except (ValueError, NotImplementedError):
return self
if exp.is_positive:
newn = ceiling(n/exp)
o = Order(x**n, x)
r = (z/2)._eval_nseries(x, n, logx, cdir).removeO()
if r is S.Zero:
return o
t = (_mexpand(r**2) + o).removeO()
term = r**nu/gamma(nu + 1)
s = [term]
for k in range(1, (newn + 1)//2):
term *= t/(k*(nu + k))
term = (_mexpand(term) + o).removeO()
s.append(term)
return Add(*s) + o
return super(besseli, self)._eval_nseries(x, n, logx, cdir)
class besselk(BesselBase):
r"""
Modified Bessel function of the second kind.
Explanation
===========
The Bessel $K$ function of order $\nu$ is defined as
.. math ::
K_\nu(z) = \lim_{\mu \to \nu} \frac{\pi}{2}
\frac{I_{-\mu}(z) -I_\mu(z)}{\sin(\pi \mu)},
where $I_\mu(z)$ is the modified Bessel function of the first kind.
It is a solution of the modified Bessel equation, and linearly independent
from $Y_\nu$.
Examples
========
>>> from sympy import besselk
>>> from sympy.abc import z, n
>>> besselk(n, z).diff(z)
-besselk(n - 1, z)/2 - besselk(n + 1, z)/2
See Also
========
besselj, besseli, bessely
References
==========
.. [1] https://functions.wolfram.com/Bessel-TypeFunctions/BesselK/
"""
_a = S.One
_b = -S.One
@classmethod
def eval(cls, nu, z):
if z.is_zero:
if nu.is_zero:
return S.Infinity
elif re(nu).is_zero is False:
return S.ComplexInfinity
elif re(nu).is_zero:
return S.NaN
if z in (S.Infinity, I*S.Infinity, I*S.NegativeInfinity):
return S.Zero
if nu.is_integer:
if nu.could_extract_minus_sign():
return besselk(-nu, z)
def _eval_rewrite_as_besseli(self, nu, z, **kwargs):
if nu.is_integer is False:
return pi*csc(pi*nu)*(besseli(-nu, z) - besseli(nu, z))/2
def _eval_rewrite_as_besselj(self, nu, z, **kwargs):
ai = self._eval_rewrite_as_besseli(*self.args)
if ai:
return ai.rewrite(besselj)
def _eval_rewrite_as_bessely(self, nu, z, **kwargs):
aj = self._eval_rewrite_as_besselj(*self.args)
if aj:
return aj.rewrite(bessely)
def _eval_rewrite_as_yn(self, nu, z, **kwargs):
ay = self._eval_rewrite_as_bessely(*self.args)
if ay:
return ay.rewrite(yn)
def _eval_is_extended_real(self):
nu, z = self.args
if nu.is_integer and z.is_positive:
return True
def _eval_as_leading_term(self, x, logx=None, cdir=0):
nu, z = self.args
try:
arg = z.as_leading_term(x)
except NotImplementedError:
return self
_, e = arg.as_coeff_exponent(x)
if e.is_positive:
term_one = ((-1)**(nu -1)*log(z/2)*besseli(nu, z))
term_two = (z/2)**(-nu)*factorial(nu - 1)/2 if (nu).is_positive else S.Zero
term_three = (-1)**nu*(z/2)**nu/(2*factorial(nu))*(digamma(nu + 1) - S.EulerGamma)
arg = Add(*[term_one, term_two, term_three]).as_leading_term(x, logx=logx)
return arg
elif e.is_negative:
# Refer Abramowitz and Stegun 1965, p. 378 for more information on
# asymptotic approximation of besselk function.
return sqrt(pi)*exp(-z)/sqrt(2*z)
return super(besselk, self)._eval_as_leading_term(x, logx, cdir)
def _eval_nseries(self, x, n, logx, cdir=0):
# Refer https://functions.wolfram.com/Bessel-TypeFunctions/BesselK/06/01/04/01/02/0008/
# for more information on nseries expansion of besselk function.
from sympy.series.order import Order
nu, z = self.args
# In case of powers less than 1, number of terms need to be computed
# separately to avoid repeated callings of _eval_nseries with wrong n
try:
_, exp = z.leadterm(x)
except (ValueError, NotImplementedError):
return self
if exp.is_positive and nu.is_integer:
newn = ceiling(n/exp)
bn = besseli(nu, z)
a = ((-1)**(nu - 1)*log(z/2)*bn)._eval_nseries(x, n, logx, cdir)
b, c = [], []
o = Order(x**n, x)
r = (z/2)._eval_nseries(x, n, logx, cdir).removeO()
if r is S.Zero:
return o
t = (_mexpand(r**2) + o).removeO()
if nu > S.Zero:
term = r**(-nu)*factorial(nu - 1)/2
b.append(term)
for k in range(1, nu):
denom = (k - nu)*k
if denom == S.Zero:
term *= t/k
else:
term *= t/denom
term = (_mexpand(term) + o).removeO()
b.append(term)
p = r**nu*(-1)**nu/(2*factorial(nu))
term = p*(digamma(nu + 1) - S.EulerGamma)
c.append(term)
for k in range(1, (newn + 1)//2):
p *= t/(k*(k + nu))
p = (_mexpand(p) + o).removeO()
term = p*(digamma(k + nu + 1) + digamma(k + 1))
c.append(term)
return a + Add(*b) + Add(*c) # Order term comes from a
return super(besselk, self)._eval_nseries(x, n, logx, cdir)
class hankel1(BesselBase):
r"""
Hankel function of the first kind.
Explanation
===========
This function is defined as
.. math ::
H_\nu^{(1)} = J_\nu(z) + iY_\nu(z),
where $J_\nu(z)$ is the Bessel function of the first kind, and
$Y_\nu(z)$ is the Bessel function of the second kind.
It is a solution to Bessel's equation.
Examples
========
>>> from sympy import hankel1
>>> from sympy.abc import z, n
>>> hankel1(n, z).diff(z)
hankel1(n - 1, z)/2 - hankel1(n + 1, z)/2
See Also
========
hankel2, besselj, bessely
References
==========
.. [1] https://functions.wolfram.com/Bessel-TypeFunctions/HankelH1/
"""
_a = S.One
_b = S.One
def _eval_conjugate(self):
z = self.argument
if z.is_extended_negative is False:
return hankel2(self.order.conjugate(), z.conjugate())
class hankel2(BesselBase):
r"""
Hankel function of the second kind.
Explanation
===========
This function is defined as
.. math ::
H_\nu^{(2)} = J_\nu(z) - iY_\nu(z),
where $J_\nu(z)$ is the Bessel function of the first kind, and
$Y_\nu(z)$ is the Bessel function of the second kind.
It is a solution to Bessel's equation, and linearly independent from
$H_\nu^{(1)}$.
Examples
========
>>> from sympy import hankel2
>>> from sympy.abc import z, n
>>> hankel2(n, z).diff(z)
hankel2(n - 1, z)/2 - hankel2(n + 1, z)/2
See Also
========
hankel1, besselj, bessely
References
==========
.. [1] https://functions.wolfram.com/Bessel-TypeFunctions/HankelH2/
"""
_a = S.One
_b = S.One
def _eval_conjugate(self):
z = self.argument
if z.is_extended_negative is False:
return hankel1(self.order.conjugate(), z.conjugate())
def assume_integer_order(fn):
@wraps(fn)
def g(self, nu, z):
if nu.is_integer:
return fn(self, nu, z)
return g
class SphericalBesselBase(BesselBase):
"""
Base class for spherical Bessel functions.
These are thin wrappers around ordinary Bessel functions,
since spherical Bessel functions differ from the ordinary
ones just by a slight change in order.
To use this class, define the ``_eval_evalf()`` and ``_expand()`` methods.
"""
def _expand(self, **hints):
""" Expand self into a polynomial. Nu is guaranteed to be Integer. """
raise NotImplementedError('expansion')
def _eval_expand_func(self, **hints):
if self.order.is_Integer:
return self._expand(**hints)
return self
def fdiff(self, argindex=2):
if argindex != 2:
raise ArgumentIndexError(self, argindex)
return self.__class__(self.order - 1, self.argument) - \
self * (self.order + 1)/self.argument
def _jn(n, z):
return (spherical_bessel_fn(n, z)*sin(z) +
S.NegativeOne**(n + 1)*spherical_bessel_fn(-n - 1, z)*cos(z))
def _yn(n, z):
# (-1)**(n + 1) * _jn(-n - 1, z)
return (S.NegativeOne**(n + 1) * spherical_bessel_fn(-n - 1, z)*sin(z) -
spherical_bessel_fn(n, z)*cos(z))
class jn(SphericalBesselBase):
r"""
Spherical Bessel function of the first kind.
Explanation
===========
This function is a solution to the spherical Bessel equation
.. math ::
z^2 \frac{\mathrm{d}^2 w}{\mathrm{d}z^2}
+ 2z \frac{\mathrm{d}w}{\mathrm{d}z} + (z^2 - \nu(\nu + 1)) w = 0.
It can be defined as
.. math ::
j_\nu(z) = \sqrt{\frac{\pi}{2z}} J_{\nu + \frac{1}{2}}(z),
where $J_\nu(z)$ is the Bessel function of the first kind.
The spherical Bessel functions of integral order are
calculated using the formula:
.. math:: j_n(z) = f_n(z) \sin{z} + (-1)^{n+1} f_{-n-1}(z) \cos{z},
where the coefficients $f_n(z)$ are available as
:func:`sympy.polys.orthopolys.spherical_bessel_fn`.
Examples
========
>>> from sympy import Symbol, jn, sin, cos, expand_func, besselj, bessely
>>> z = Symbol("z")
>>> nu = Symbol("nu", integer=True)
>>> print(expand_func(jn(0, z)))
sin(z)/z
>>> expand_func(jn(1, z)) == sin(z)/z**2 - cos(z)/z
True
>>> expand_func(jn(3, z))
(-6/z**2 + 15/z**4)*sin(z) + (1/z - 15/z**3)*cos(z)
>>> jn(nu, z).rewrite(besselj)
sqrt(2)*sqrt(pi)*sqrt(1/z)*besselj(nu + 1/2, z)/2
>>> jn(nu, z).rewrite(bessely)
(-1)**nu*sqrt(2)*sqrt(pi)*sqrt(1/z)*bessely(-nu - 1/2, z)/2
>>> jn(2, 5.2+0.3j).evalf(20)
0.099419756723640344491 - 0.054525080242173562897*I
See Also
========
besselj, bessely, besselk, yn
References
==========
.. [1] https://dlmf.nist.gov/10.47
"""
@classmethod
def eval(cls, nu, z):
if z.is_zero:
if nu.is_zero:
return S.One
elif nu.is_integer:
if nu.is_positive:
return S.Zero
else:
return S.ComplexInfinity
if z in (S.NegativeInfinity, S.Infinity):
return S.Zero
def _eval_rewrite_as_besselj(self, nu, z, **kwargs):
return sqrt(pi/(2*z)) * besselj(nu + S.Half, z)
def _eval_rewrite_as_bessely(self, nu, z, **kwargs):
return S.NegativeOne**nu * sqrt(pi/(2*z)) * bessely(-nu - S.Half, z)
def _eval_rewrite_as_yn(self, nu, z, **kwargs):
return S.NegativeOne**(nu) * yn(-nu - 1, z)
def _expand(self, **hints):
return _jn(self.order, self.argument)
def _eval_evalf(self, prec):
if self.order.is_Integer:
return self.rewrite(besselj)._eval_evalf(prec)
class yn(SphericalBesselBase):
r"""
Spherical Bessel function of the second kind.
Explanation
===========
This function is another solution to the spherical Bessel equation, and
linearly independent from $j_n$. It can be defined as
.. math ::
y_\nu(z) = \sqrt{\frac{\pi}{2z}} Y_{\nu + \frac{1}{2}}(z),
where $Y_\nu(z)$ is the Bessel function of the second kind.
For integral orders $n$, $y_n$ is calculated using the formula:
.. math:: y_n(z) = (-1)^{n+1} j_{-n-1}(z)
Examples
========
>>> from sympy import Symbol, yn, sin, cos, expand_func, besselj, bessely
>>> z = Symbol("z")
>>> nu = Symbol("nu", integer=True)
>>> print(expand_func(yn(0, z)))
-cos(z)/z
>>> expand_func(yn(1, z)) == -cos(z)/z**2-sin(z)/z
True
>>> yn(nu, z).rewrite(besselj)
(-1)**(nu + 1)*sqrt(2)*sqrt(pi)*sqrt(1/z)*besselj(-nu - 1/2, z)/2
>>> yn(nu, z).rewrite(bessely)
sqrt(2)*sqrt(pi)*sqrt(1/z)*bessely(nu + 1/2, z)/2
>>> yn(2, 5.2+0.3j).evalf(20)
0.18525034196069722536 + 0.014895573969924817587*I
See Also
========
besselj, bessely, besselk, jn
References
==========
.. [1] https://dlmf.nist.gov/10.47
"""
@assume_integer_order
def _eval_rewrite_as_besselj(self, nu, z, **kwargs):
return S.NegativeOne**(nu+1) * sqrt(pi/(2*z)) * besselj(-nu - S.Half, z)
@assume_integer_order
def _eval_rewrite_as_bessely(self, nu, z, **kwargs):
return sqrt(pi/(2*z)) * bessely(nu + S.Half, z)
def _eval_rewrite_as_jn(self, nu, z, **kwargs):
return S.NegativeOne**(nu + 1) * jn(-nu - 1, z)
def _expand(self, **hints):
return _yn(self.order, self.argument)
def _eval_evalf(self, prec):
if self.order.is_Integer:
return self.rewrite(bessely)._eval_evalf(prec)
class SphericalHankelBase(SphericalBesselBase):
@assume_integer_order
def _eval_rewrite_as_besselj(self, nu, z, **kwargs):
# jn +- I*yn
# jn as beeselj: sqrt(pi/(2*z)) * besselj(nu + S.Half, z)
# yn as besselj: (-1)**(nu+1) * sqrt(pi/(2*z)) * besselj(-nu - S.Half, z)
hks = self._hankel_kind_sign
return sqrt(pi/(2*z))*(besselj(nu + S.Half, z) +
hks*I*S.NegativeOne**(nu+1)*besselj(-nu - S.Half, z))
@assume_integer_order
def _eval_rewrite_as_bessely(self, nu, z, **kwargs):
# jn +- I*yn
# jn as bessely: (-1)**nu * sqrt(pi/(2*z)) * bessely(-nu - S.Half, z)
# yn as bessely: sqrt(pi/(2*z)) * bessely(nu + S.Half, z)
hks = self._hankel_kind_sign
return sqrt(pi/(2*z))*(S.NegativeOne**nu*bessely(-nu - S.Half, z) +
hks*I*bessely(nu + S.Half, z))
def _eval_rewrite_as_yn(self, nu, z, **kwargs):
hks = self._hankel_kind_sign
return jn(nu, z).rewrite(yn) + hks*I*yn(nu, z)
def _eval_rewrite_as_jn(self, nu, z, **kwargs):
hks = self._hankel_kind_sign
return jn(nu, z) + hks*I*yn(nu, z).rewrite(jn)
def _eval_expand_func(self, **hints):
if self.order.is_Integer:
return self._expand(**hints)
else:
nu = self.order
z = self.argument
hks = self._hankel_kind_sign
return jn(nu, z) + hks*I*yn(nu, z)
def _expand(self, **hints):
n = self.order
z = self.argument
hks = self._hankel_kind_sign
# fully expanded version
# return ((fn(n, z) * sin(z) +
# (-1)**(n + 1) * fn(-n - 1, z) * cos(z)) + # jn
# (hks * I * (-1)**(n + 1) *
# (fn(-n - 1, z) * hk * I * sin(z) +
# (-1)**(-n) * fn(n, z) * I * cos(z))) # +-I*yn
# )
return (_jn(n, z) + hks*I*_yn(n, z)).expand()
def _eval_evalf(self, prec):
if self.order.is_Integer:
return self.rewrite(besselj)._eval_evalf(prec)
class hn1(SphericalHankelBase):
r"""
Spherical Hankel function of the first kind.
Explanation
===========
This function is defined as
.. math:: h_\nu^(1)(z) = j_\nu(z) + i y_\nu(z),
where $j_\nu(z)$ and $y_\nu(z)$ are the spherical
Bessel function of the first and second kinds.
For integral orders $n$, $h_n^(1)$ is calculated using the formula:
.. math:: h_n^(1)(z) = j_{n}(z) + i (-1)^{n+1} j_{-n-1}(z)
Examples
========
>>> from sympy import Symbol, hn1, hankel1, expand_func, yn, jn
>>> z = Symbol("z")
>>> nu = Symbol("nu", integer=True)
>>> print(expand_func(hn1(nu, z)))
jn(nu, z) + I*yn(nu, z)
>>> print(expand_func(hn1(0, z)))
sin(z)/z - I*cos(z)/z
>>> print(expand_func(hn1(1, z)))
-I*sin(z)/z - cos(z)/z + sin(z)/z**2 - I*cos(z)/z**2
>>> hn1(nu, z).rewrite(jn)
(-1)**(nu + 1)*I*jn(-nu - 1, z) + jn(nu, z)
>>> hn1(nu, z).rewrite(yn)
(-1)**nu*yn(-nu - 1, z) + I*yn(nu, z)
>>> hn1(nu, z).rewrite(hankel1)
sqrt(2)*sqrt(pi)*sqrt(1/z)*hankel1(nu, z)/2
See Also
========
hn2, jn, yn, hankel1, hankel2
References
==========
.. [1] https://dlmf.nist.gov/10.47
"""
_hankel_kind_sign = S.One
@assume_integer_order
def _eval_rewrite_as_hankel1(self, nu, z, **kwargs):
return sqrt(pi/(2*z))*hankel1(nu, z)
class hn2(SphericalHankelBase):
r"""
Spherical Hankel function of the second kind.
Explanation
===========
This function is defined as
.. math:: h_\nu^(2)(z) = j_\nu(z) - i y_\nu(z),
where $j_\nu(z)$ and $y_\nu(z)$ are the spherical
Bessel function of the first and second kinds.
For integral orders $n$, $h_n^(2)$ is calculated using the formula:
.. math:: h_n^(2)(z) = j_{n} - i (-1)^{n+1} j_{-n-1}(z)
Examples
========
>>> from sympy import Symbol, hn2, hankel2, expand_func, jn, yn
>>> z = Symbol("z")
>>> nu = Symbol("nu", integer=True)
>>> print(expand_func(hn2(nu, z)))
jn(nu, z) - I*yn(nu, z)
>>> print(expand_func(hn2(0, z)))
sin(z)/z + I*cos(z)/z
>>> print(expand_func(hn2(1, z)))
I*sin(z)/z - cos(z)/z + sin(z)/z**2 + I*cos(z)/z**2
>>> hn2(nu, z).rewrite(hankel2)
sqrt(2)*sqrt(pi)*sqrt(1/z)*hankel2(nu, z)/2
>>> hn2(nu, z).rewrite(jn)
-(-1)**(nu + 1)*I*jn(-nu - 1, z) + jn(nu, z)
>>> hn2(nu, z).rewrite(yn)
(-1)**nu*yn(-nu - 1, z) - I*yn(nu, z)
See Also
========
hn1, jn, yn, hankel1, hankel2
References
==========
.. [1] https://dlmf.nist.gov/10.47
"""
_hankel_kind_sign = -S.One
@assume_integer_order
def _eval_rewrite_as_hankel2(self, nu, z, **kwargs):
return sqrt(pi/(2*z))*hankel2(nu, z)
def jn_zeros(n, k, method="sympy", dps=15):
"""
Zeros of the spherical Bessel function of the first kind.
Explanation
===========
This returns an array of zeros of $jn$ up to the $k$-th zero.
* method = "sympy": uses `mpmath.besseljzero
<https://mpmath.org/doc/current/functions/bessel.html#mpmath.besseljzero>`_
* method = "scipy": uses the
`SciPy's sph_jn <https://docs.scipy.org/doc/scipy/reference/generated/scipy.special.jn_zeros.html>`_
and
`newton <https://docs.scipy.org/doc/scipy/reference/generated/scipy.optimize.newton.html>`_
to find all
roots, which is faster than computing the zeros using a general
numerical solver, but it requires SciPy and only works with low
precision floating point numbers. (The function used with
method="sympy" is a recent addition to mpmath; before that a general
solver was used.)
Examples
========
>>> from sympy import jn_zeros
>>> jn_zeros(2, 4, dps=5)
[5.7635, 9.095, 12.323, 15.515]
See Also
========
jn, yn, besselj, besselk, bessely
Parameters
==========
n : integer
order of Bessel function
k : integer
number of zeros to return
"""
from math import pi as math_pi
if method == "sympy":
from mpmath import besseljzero
from mpmath.libmp.libmpf import dps_to_prec
prec = dps_to_prec(dps)
return [Expr._from_mpmath(besseljzero(S(n + 0.5)._to_mpmath(prec),
int(l)), prec)
for l in range(1, k + 1)]
elif method == "scipy":
from scipy.optimize import newton
try:
from scipy.special import spherical_jn
f = lambda x: spherical_jn(n, x)
except ImportError:
from scipy.special import sph_jn
f = lambda x: sph_jn(n, x)[0][-1]
else:
raise NotImplementedError("Unknown method.")
def solver(f, x):
if method == "scipy":
root = newton(f, x)
else:
raise NotImplementedError("Unknown method.")
return root
# we need to approximate the position of the first root:
root = n + math_pi
# determine the first root exactly:
root = solver(f, root)
roots = [root]
for i in range(k - 1):
# estimate the position of the next root using the last root + pi:
root = solver(f, root + math_pi)
roots.append(root)
return roots
class AiryBase(Function):
"""
Abstract base class for Airy functions.
This class is meant to reduce code duplication.
"""
def _eval_conjugate(self):
return self.func(self.args[0].conjugate())
def _eval_is_extended_real(self):
return self.args[0].is_extended_real
def as_real_imag(self, deep=True, **hints):
z = self.args[0]
zc = z.conjugate()
f = self.func
u = (f(z)+f(zc))/2
v = I*(f(zc)-f(z))/2
return u, v
def _eval_expand_complex(self, deep=True, **hints):
re_part, im_part = self.as_real_imag(deep=deep, **hints)
return re_part + im_part*I
class airyai(AiryBase):
r"""
The Airy function $\operatorname{Ai}$ of the first kind.
Explanation
===========
The Airy function $\operatorname{Ai}(z)$ is defined to be the function
satisfying Airy's differential equation
.. math::
\frac{\mathrm{d}^2 w(z)}{\mathrm{d}z^2} - z w(z) = 0.
Equivalently, for real $z$
.. math::
\operatorname{Ai}(z) := \frac{1}{\pi}
\int_0^\infty \cos\left(\frac{t^3}{3} + z t\right) \mathrm{d}t.
Examples
========
Create an Airy function object:
>>> from sympy import airyai
>>> from sympy.abc import z
>>> airyai(z)
airyai(z)
Several special values are known:
>>> airyai(0)
3**(1/3)/(3*gamma(2/3))
>>> from sympy import oo
>>> airyai(oo)
0
>>> airyai(-oo)
0
The Airy function obeys the mirror symmetry:
>>> from sympy import conjugate
>>> conjugate(airyai(z))
airyai(conjugate(z))
Differentiation with respect to $z$ is supported:
>>> from sympy import diff
>>> diff(airyai(z), z)
airyaiprime(z)
>>> diff(airyai(z), z, 2)
z*airyai(z)
Series expansion is also supported:
>>> from sympy import series
>>> series(airyai(z), z, 0, 3)
3**(5/6)*gamma(1/3)/(6*pi) - 3**(1/6)*z*gamma(2/3)/(2*pi) + O(z**3)
We can numerically evaluate the Airy function to arbitrary precision
on the whole complex plane:
>>> airyai(-2).evalf(50)
0.22740742820168557599192443603787379946077222541710
Rewrite $\operatorname{Ai}(z)$ in terms of hypergeometric functions:
>>> from sympy import hyper
>>> airyai(z).rewrite(hyper)
-3**(2/3)*z*hyper((), (4/3,), z**3/9)/(3*gamma(1/3)) + 3**(1/3)*hyper((), (2/3,), z**3/9)/(3*gamma(2/3))
See Also
========
airybi: Airy function of the second kind.
airyaiprime: Derivative of the Airy function of the first kind.
airybiprime: Derivative of the Airy function of the second kind.
References
==========
.. [1] https://en.wikipedia.org/wiki/Airy_function
.. [2] https://dlmf.nist.gov/9
.. [3] https://encyclopediaofmath.org/wiki/Airy_functions
.. [4] https://mathworld.wolfram.com/AiryFunctions.html
"""
nargs = 1
unbranched = True
@classmethod
def eval(cls, arg):
if arg.is_Number:
if arg is S.NaN:
return S.NaN
elif arg is S.Infinity:
return S.Zero
elif arg is S.NegativeInfinity:
return S.Zero
elif arg.is_zero:
return S.One / (3**Rational(2, 3) * gamma(Rational(2, 3)))
if arg.is_zero:
return S.One / (3**Rational(2, 3) * gamma(Rational(2, 3)))
def fdiff(self, argindex=1):
if argindex == 1:
return airyaiprime(self.args[0])
else:
raise ArgumentIndexError(self, argindex)
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
if n < 0:
return S.Zero
else:
x = sympify(x)
if len(previous_terms) > 1:
p = previous_terms[-1]
return ((cbrt(3)*x)**(-n)*(cbrt(3)*x)**(n + 1)*sin(pi*(n*Rational(2, 3) + Rational(4, 3)))*factorial(n) *
gamma(n/3 + Rational(2, 3))/(sin(pi*(n*Rational(2, 3) + Rational(2, 3)))*factorial(n + 1)*gamma(n/3 + Rational(1, 3))) * p)
else:
return (S.One/(3**Rational(2, 3)*pi) * gamma((n+S.One)/S(3)) * sin(Rational(2, 3)*pi*(n+S.One)) /
factorial(n) * (cbrt(3)*x)**n)
def _eval_rewrite_as_besselj(self, z, **kwargs):
ot = Rational(1, 3)
tt = Rational(2, 3)
a = Pow(-z, Rational(3, 2))
if re(z).is_negative:
return ot*sqrt(-z) * (besselj(-ot, tt*a) + besselj(ot, tt*a))
def _eval_rewrite_as_besseli(self, z, **kwargs):
ot = Rational(1, 3)
tt = Rational(2, 3)
a = Pow(z, Rational(3, 2))
if re(z).is_positive:
return ot*sqrt(z) * (besseli(-ot, tt*a) - besseli(ot, tt*a))
else:
return ot*(Pow(a, ot)*besseli(-ot, tt*a) - z*Pow(a, -ot)*besseli(ot, tt*a))
def _eval_rewrite_as_hyper(self, z, **kwargs):
pf1 = S.One / (3**Rational(2, 3)*gamma(Rational(2, 3)))
pf2 = z / (root(3, 3)*gamma(Rational(1, 3)))
return pf1 * hyper([], [Rational(2, 3)], z**3/9) - pf2 * hyper([], [Rational(4, 3)], z**3/9)
def _eval_expand_func(self, **hints):
arg = self.args[0]
symbs = arg.free_symbols
if len(symbs) == 1:
z = symbs.pop()
c = Wild("c", exclude=[z])
d = Wild("d", exclude=[z])
m = Wild("m", exclude=[z])
n = Wild("n", exclude=[z])
M = arg.match(c*(d*z**n)**m)
if M is not None:
m = M[m]
# The transformation is given by 03.05.16.0001.01
# https://functions.wolfram.com/Bessel-TypeFunctions/AiryAi/16/01/01/0001/
if (3*m).is_integer:
c = M[c]
d = M[d]
n = M[n]
pf = (d * z**n)**m / (d**m * z**(m*n))
newarg = c * d**m * z**(m*n)
return S.Half * ((pf + S.One)*airyai(newarg) - (pf - S.One)/sqrt(3)*airybi(newarg))
class airybi(AiryBase):
r"""
The Airy function $\operatorname{Bi}$ of the second kind.
Explanation
===========
The Airy function $\operatorname{Bi}(z)$ is defined to be the function
satisfying Airy's differential equation
.. math::
\frac{\mathrm{d}^2 w(z)}{\mathrm{d}z^2} - z w(z) = 0.
Equivalently, for real $z$
.. math::
\operatorname{Bi}(z) := \frac{1}{\pi}
\int_0^\infty
\exp\left(-\frac{t^3}{3} + z t\right)
+ \sin\left(\frac{t^3}{3} + z t\right) \mathrm{d}t.
Examples
========
Create an Airy function object:
>>> from sympy import airybi
>>> from sympy.abc import z
>>> airybi(z)
airybi(z)
Several special values are known:
>>> airybi(0)
3**(5/6)/(3*gamma(2/3))
>>> from sympy import oo
>>> airybi(oo)
oo
>>> airybi(-oo)
0
The Airy function obeys the mirror symmetry:
>>> from sympy import conjugate
>>> conjugate(airybi(z))
airybi(conjugate(z))
Differentiation with respect to $z$ is supported:
>>> from sympy import diff
>>> diff(airybi(z), z)
airybiprime(z)
>>> diff(airybi(z), z, 2)
z*airybi(z)
Series expansion is also supported:
>>> from sympy import series
>>> series(airybi(z), z, 0, 3)
3**(1/3)*gamma(1/3)/(2*pi) + 3**(2/3)*z*gamma(2/3)/(2*pi) + O(z**3)
We can numerically evaluate the Airy function to arbitrary precision
on the whole complex plane:
>>> airybi(-2).evalf(50)
-0.41230258795639848808323405461146104203453483447240
Rewrite $\operatorname{Bi}(z)$ in terms of hypergeometric functions:
>>> from sympy import hyper
>>> airybi(z).rewrite(hyper)
3**(1/6)*z*hyper((), (4/3,), z**3/9)/gamma(1/3) + 3**(5/6)*hyper((), (2/3,), z**3/9)/(3*gamma(2/3))
See Also
========
airyai: Airy function of the first kind.
airyaiprime: Derivative of the Airy function of the first kind.
airybiprime: Derivative of the Airy function of the second kind.
References
==========
.. [1] https://en.wikipedia.org/wiki/Airy_function
.. [2] https://dlmf.nist.gov/9
.. [3] https://encyclopediaofmath.org/wiki/Airy_functions
.. [4] https://mathworld.wolfram.com/AiryFunctions.html
"""
nargs = 1
unbranched = True
@classmethod
def eval(cls, arg):
if arg.is_Number:
if arg is S.NaN:
return S.NaN
elif arg is S.Infinity:
return S.Infinity
elif arg is S.NegativeInfinity:
return S.Zero
elif arg.is_zero:
return S.One / (3**Rational(1, 6) * gamma(Rational(2, 3)))
if arg.is_zero:
return S.One / (3**Rational(1, 6) * gamma(Rational(2, 3)))
def fdiff(self, argindex=1):
if argindex == 1:
return airybiprime(self.args[0])
else:
raise ArgumentIndexError(self, argindex)
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
if n < 0:
return S.Zero
else:
x = sympify(x)
if len(previous_terms) > 1:
p = previous_terms[-1]
return (cbrt(3)*x * Abs(sin(Rational(2, 3)*pi*(n + S.One))) * factorial((n - S.One)/S(3)) /
((n + S.One) * Abs(cos(Rational(2, 3)*pi*(n + S.Half))) * factorial((n - 2)/S(3))) * p)
else:
return (S.One/(root(3, 6)*pi) * gamma((n + S.One)/S(3)) * Abs(sin(Rational(2, 3)*pi*(n + S.One))) /
factorial(n) * (cbrt(3)*x)**n)
def _eval_rewrite_as_besselj(self, z, **kwargs):
ot = Rational(1, 3)
tt = Rational(2, 3)
a = Pow(-z, Rational(3, 2))
if re(z).is_negative:
return sqrt(-z/3) * (besselj(-ot, tt*a) - besselj(ot, tt*a))
def _eval_rewrite_as_besseli(self, z, **kwargs):
ot = Rational(1, 3)
tt = Rational(2, 3)
a = Pow(z, Rational(3, 2))
if re(z).is_positive:
return sqrt(z)/sqrt(3) * (besseli(-ot, tt*a) + besseli(ot, tt*a))
else:
b = Pow(a, ot)
c = Pow(a, -ot)
return sqrt(ot)*(b*besseli(-ot, tt*a) + z*c*besseli(ot, tt*a))
def _eval_rewrite_as_hyper(self, z, **kwargs):
pf1 = S.One / (root(3, 6)*gamma(Rational(2, 3)))
pf2 = z*root(3, 6) / gamma(Rational(1, 3))
return pf1 * hyper([], [Rational(2, 3)], z**3/9) + pf2 * hyper([], [Rational(4, 3)], z**3/9)
def _eval_expand_func(self, **hints):
arg = self.args[0]
symbs = arg.free_symbols
if len(symbs) == 1:
z = symbs.pop()
c = Wild("c", exclude=[z])
d = Wild("d", exclude=[z])
m = Wild("m", exclude=[z])
n = Wild("n", exclude=[z])
M = arg.match(c*(d*z**n)**m)
if M is not None:
m = M[m]
# The transformation is given by 03.06.16.0001.01
# https://functions.wolfram.com/Bessel-TypeFunctions/AiryBi/16/01/01/0001/
if (3*m).is_integer:
c = M[c]
d = M[d]
n = M[n]
pf = (d * z**n)**m / (d**m * z**(m*n))
newarg = c * d**m * z**(m*n)
return S.Half * (sqrt(3)*(S.One - pf)*airyai(newarg) + (S.One + pf)*airybi(newarg))
class airyaiprime(AiryBase):
r"""
The derivative $\operatorname{Ai}^\prime$ of the Airy function of the first
kind.
Explanation
===========
The Airy function $\operatorname{Ai}^\prime(z)$ is defined to be the
function
.. math::
\operatorname{Ai}^\prime(z) := \frac{\mathrm{d} \operatorname{Ai}(z)}{\mathrm{d} z}.
Examples
========
Create an Airy function object:
>>> from sympy import airyaiprime
>>> from sympy.abc import z
>>> airyaiprime(z)
airyaiprime(z)
Several special values are known:
>>> airyaiprime(0)
-3**(2/3)/(3*gamma(1/3))
>>> from sympy import oo
>>> airyaiprime(oo)
0
The Airy function obeys the mirror symmetry:
>>> from sympy import conjugate
>>> conjugate(airyaiprime(z))
airyaiprime(conjugate(z))
Differentiation with respect to $z$ is supported:
>>> from sympy import diff
>>> diff(airyaiprime(z), z)
z*airyai(z)
>>> diff(airyaiprime(z), z, 2)
z*airyaiprime(z) + airyai(z)
Series expansion is also supported:
>>> from sympy import series
>>> series(airyaiprime(z), z, 0, 3)
-3**(2/3)/(3*gamma(1/3)) + 3**(1/3)*z**2/(6*gamma(2/3)) + O(z**3)
We can numerically evaluate the Airy function to arbitrary precision
on the whole complex plane:
>>> airyaiprime(-2).evalf(50)
0.61825902074169104140626429133247528291577794512415
Rewrite $\operatorname{Ai}^\prime(z)$ in terms of hypergeometric functions:
>>> from sympy import hyper
>>> airyaiprime(z).rewrite(hyper)
3**(1/3)*z**2*hyper((), (5/3,), z**3/9)/(6*gamma(2/3)) - 3**(2/3)*hyper((), (1/3,), z**3/9)/(3*gamma(1/3))
See Also
========
airyai: Airy function of the first kind.
airybi: Airy function of the second kind.
airybiprime: Derivative of the Airy function of the second kind.
References
==========
.. [1] https://en.wikipedia.org/wiki/Airy_function
.. [2] https://dlmf.nist.gov/9
.. [3] https://encyclopediaofmath.org/wiki/Airy_functions
.. [4] https://mathworld.wolfram.com/AiryFunctions.html
"""
nargs = 1
unbranched = True
@classmethod
def eval(cls, arg):
if arg.is_Number:
if arg is S.NaN:
return S.NaN
elif arg is S.Infinity:
return S.Zero
if arg.is_zero:
return S.NegativeOne / (3**Rational(1, 3) * gamma(Rational(1, 3)))
def fdiff(self, argindex=1):
if argindex == 1:
return self.args[0]*airyai(self.args[0])
else:
raise ArgumentIndexError(self, argindex)
def _eval_evalf(self, prec):
z = self.args[0]._to_mpmath(prec)
with workprec(prec):
res = mp.airyai(z, derivative=1)
return Expr._from_mpmath(res, prec)
def _eval_rewrite_as_besselj(self, z, **kwargs):
tt = Rational(2, 3)
a = Pow(-z, Rational(3, 2))
if re(z).is_negative:
return z/3 * (besselj(-tt, tt*a) - besselj(tt, tt*a))
def _eval_rewrite_as_besseli(self, z, **kwargs):
ot = Rational(1, 3)
tt = Rational(2, 3)
a = tt * Pow(z, Rational(3, 2))
if re(z).is_positive:
return z/3 * (besseli(tt, a) - besseli(-tt, a))
else:
a = Pow(z, Rational(3, 2))
b = Pow(a, tt)
c = Pow(a, -tt)
return ot * (z**2*c*besseli(tt, tt*a) - b*besseli(-ot, tt*a))
def _eval_rewrite_as_hyper(self, z, **kwargs):
pf1 = z**2 / (2*3**Rational(2, 3)*gamma(Rational(2, 3)))
pf2 = 1 / (root(3, 3)*gamma(Rational(1, 3)))
return pf1 * hyper([], [Rational(5, 3)], z**3/9) - pf2 * hyper([], [Rational(1, 3)], z**3/9)
def _eval_expand_func(self, **hints):
arg = self.args[0]
symbs = arg.free_symbols
if len(symbs) == 1:
z = symbs.pop()
c = Wild("c", exclude=[z])
d = Wild("d", exclude=[z])
m = Wild("m", exclude=[z])
n = Wild("n", exclude=[z])
M = arg.match(c*(d*z**n)**m)
if M is not None:
m = M[m]
# The transformation is in principle
# given by 03.07.16.0001.01 but note
# that there is an error in this formula.
# https://functions.wolfram.com/Bessel-TypeFunctions/AiryAiPrime/16/01/01/0001/
if (3*m).is_integer:
c = M[c]
d = M[d]
n = M[n]
pf = (d**m * z**(n*m)) / (d * z**n)**m
newarg = c * d**m * z**(n*m)
return S.Half * ((pf + S.One)*airyaiprime(newarg) + (pf - S.One)/sqrt(3)*airybiprime(newarg))
class airybiprime(AiryBase):
r"""
The derivative $\operatorname{Bi}^\prime$ of the Airy function of the first
kind.
Explanation
===========
The Airy function $\operatorname{Bi}^\prime(z)$ is defined to be the
function
.. math::
\operatorname{Bi}^\prime(z) := \frac{\mathrm{d} \operatorname{Bi}(z)}{\mathrm{d} z}.
Examples
========
Create an Airy function object:
>>> from sympy import airybiprime
>>> from sympy.abc import z
>>> airybiprime(z)
airybiprime(z)
Several special values are known:
>>> airybiprime(0)
3**(1/6)/gamma(1/3)
>>> from sympy import oo
>>> airybiprime(oo)
oo
>>> airybiprime(-oo)
0
The Airy function obeys the mirror symmetry:
>>> from sympy import conjugate
>>> conjugate(airybiprime(z))
airybiprime(conjugate(z))
Differentiation with respect to $z$ is supported:
>>> from sympy import diff
>>> diff(airybiprime(z), z)
z*airybi(z)
>>> diff(airybiprime(z), z, 2)
z*airybiprime(z) + airybi(z)
Series expansion is also supported:
>>> from sympy import series
>>> series(airybiprime(z), z, 0, 3)
3**(1/6)/gamma(1/3) + 3**(5/6)*z**2/(6*gamma(2/3)) + O(z**3)
We can numerically evaluate the Airy function to arbitrary precision
on the whole complex plane:
>>> airybiprime(-2).evalf(50)
0.27879516692116952268509756941098324140300059345163
Rewrite $\operatorname{Bi}^\prime(z)$ in terms of hypergeometric functions:
>>> from sympy import hyper
>>> airybiprime(z).rewrite(hyper)
3**(5/6)*z**2*hyper((), (5/3,), z**3/9)/(6*gamma(2/3)) + 3**(1/6)*hyper((), (1/3,), z**3/9)/gamma(1/3)
See Also
========
airyai: Airy function of the first kind.
airybi: Airy function of the second kind.
airyaiprime: Derivative of the Airy function of the first kind.
References
==========
.. [1] https://en.wikipedia.org/wiki/Airy_function
.. [2] https://dlmf.nist.gov/9
.. [3] https://encyclopediaofmath.org/wiki/Airy_functions
.. [4] https://mathworld.wolfram.com/AiryFunctions.html
"""
nargs = 1
unbranched = True
@classmethod
def eval(cls, arg):
if arg.is_Number:
if arg is S.NaN:
return S.NaN
elif arg is S.Infinity:
return S.Infinity
elif arg is S.NegativeInfinity:
return S.Zero
elif arg.is_zero:
return 3**Rational(1, 6) / gamma(Rational(1, 3))
if arg.is_zero:
return 3**Rational(1, 6) / gamma(Rational(1, 3))
def fdiff(self, argindex=1):
if argindex == 1:
return self.args[0]*airybi(self.args[0])
else:
raise ArgumentIndexError(self, argindex)
def _eval_evalf(self, prec):
z = self.args[0]._to_mpmath(prec)
with workprec(prec):
res = mp.airybi(z, derivative=1)
return Expr._from_mpmath(res, prec)
def _eval_rewrite_as_besselj(self, z, **kwargs):
tt = Rational(2, 3)
a = tt * Pow(-z, Rational(3, 2))
if re(z).is_negative:
return -z/sqrt(3) * (besselj(-tt, a) + besselj(tt, a))
def _eval_rewrite_as_besseli(self, z, **kwargs):
ot = Rational(1, 3)
tt = Rational(2, 3)
a = tt * Pow(z, Rational(3, 2))
if re(z).is_positive:
return z/sqrt(3) * (besseli(-tt, a) + besseli(tt, a))
else:
a = Pow(z, Rational(3, 2))
b = Pow(a, tt)
c = Pow(a, -tt)
return sqrt(ot) * (b*besseli(-tt, tt*a) + z**2*c*besseli(tt, tt*a))
def _eval_rewrite_as_hyper(self, z, **kwargs):
pf1 = z**2 / (2*root(3, 6)*gamma(Rational(2, 3)))
pf2 = root(3, 6) / gamma(Rational(1, 3))
return pf1 * hyper([], [Rational(5, 3)], z**3/9) + pf2 * hyper([], [Rational(1, 3)], z**3/9)
def _eval_expand_func(self, **hints):
arg = self.args[0]
symbs = arg.free_symbols
if len(symbs) == 1:
z = symbs.pop()
c = Wild("c", exclude=[z])
d = Wild("d", exclude=[z])
m = Wild("m", exclude=[z])
n = Wild("n", exclude=[z])
M = arg.match(c*(d*z**n)**m)
if M is not None:
m = M[m]
# The transformation is in principle
# given by 03.08.16.0001.01 but note
# that there is an error in this formula.
# https://functions.wolfram.com/Bessel-TypeFunctions/AiryBiPrime/16/01/01/0001/
if (3*m).is_integer:
c = M[c]
d = M[d]
n = M[n]
pf = (d**m * z**(n*m)) / (d * z**n)**m
newarg = c * d**m * z**(n*m)
return S.Half * (sqrt(3)*(pf - S.One)*airyaiprime(newarg) + (pf + S.One)*airybiprime(newarg))
class marcumq(Function):
r"""
The Marcum Q-function.
Explanation
===========
The Marcum Q-function is defined by the meromorphic continuation of
.. math::
Q_m(a, b) = a^{- m + 1} \int_{b}^{\infty} x^{m} e^{- \frac{a^{2}}{2} - \frac{x^{2}}{2}} I_{m - 1}\left(a x\right)\, dx
Examples
========
>>> from sympy import marcumq
>>> from sympy.abc import m, a, b
>>> marcumq(m, a, b)
marcumq(m, a, b)
Special values:
>>> marcumq(m, 0, b)
uppergamma(m, b**2/2)/gamma(m)
>>> marcumq(0, 0, 0)
0
>>> marcumq(0, a, 0)
1 - exp(-a**2/2)
>>> marcumq(1, a, a)
1/2 + exp(-a**2)*besseli(0, a**2)/2
>>> marcumq(2, a, a)
1/2 + exp(-a**2)*besseli(0, a**2)/2 + exp(-a**2)*besseli(1, a**2)
Differentiation with respect to $a$ and $b$ is supported:
>>> from sympy import diff
>>> diff(marcumq(m, a, b), a)
a*(-marcumq(m, a, b) + marcumq(m + 1, a, b))
>>> diff(marcumq(m, a, b), b)
-a**(1 - m)*b**m*exp(-a**2/2 - b**2/2)*besseli(m - 1, a*b)
References
==========
.. [1] https://en.wikipedia.org/wiki/Marcum_Q-function
.. [2] https://mathworld.wolfram.com/MarcumQ-Function.html
"""
@classmethod
def eval(cls, m, a, b):
if a is S.Zero:
if m is S.Zero and b is S.Zero:
return S.Zero
return uppergamma(m, b**2 * S.Half) / gamma(m)
if m is S.Zero and b is S.Zero:
return 1 - 1 / exp(a**2 * S.Half)
if a == b:
if m is S.One:
return (1 + exp(-a**2) * besseli(0, a**2))*S.Half
if m == 2:
return S.Half + S.Half * exp(-a**2) * besseli(0, a**2) + exp(-a**2) * besseli(1, a**2)
if a.is_zero:
if m.is_zero and b.is_zero:
return S.Zero
return uppergamma(m, b**2*S.Half) / gamma(m)
if m.is_zero and b.is_zero:
return 1 - 1 / exp(a**2*S.Half)
def fdiff(self, argindex=2):
m, a, b = self.args
if argindex == 2:
return a * (-marcumq(m, a, b) + marcumq(1+m, a, b))
elif argindex == 3:
return (-b**m / a**(m-1)) * exp(-(a**2 + b**2)/2) * besseli(m-1, a*b)
else:
raise ArgumentIndexError(self, argindex)
def _eval_rewrite_as_Integral(self, m, a, b, **kwargs):
from sympy.integrals.integrals import Integral
x = kwargs.get('x', Dummy(uniquely_named_symbol('x').name))
return a ** (1 - m) * \
Integral(x**m * exp(-(x**2 + a**2)/2) * besseli(m-1, a*x), [x, b, S.Infinity])
def _eval_rewrite_as_Sum(self, m, a, b, **kwargs):
from sympy.concrete.summations import Sum
k = kwargs.get('k', Dummy('k'))
return exp(-(a**2 + b**2) / 2) * Sum((a/b)**k * besseli(k, a*b), [k, 1-m, S.Infinity])
def _eval_rewrite_as_besseli(self, m, a, b, **kwargs):
if a == b:
if m == 1:
return (1 + exp(-a**2) * besseli(0, a**2)) / 2
if m.is_Integer and m >= 2:
s = sum(besseli(i, a**2) for i in range(1, m))
return S.Half + exp(-a**2) * besseli(0, a**2) / 2 + exp(-a**2) * s
def _eval_is_zero(self):
if all(arg.is_zero for arg in self.args):
return True
PK ]ZZZX�1 �1 ) sympy/functions/special/beta_functions.pyfrom sympy.core import S
from sympy.core.function import Function, ArgumentIndexError
from sympy.core.symbol import Dummy, uniquely_named_symbol
from sympy.functions.special.gamma_functions import gamma, digamma
from sympy.functions.combinatorial.numbers import catalan
from sympy.functions.elementary.complexes import conjugate
# See mpmath #569 and SymPy #20569
def betainc_mpmath_fix(a, b, x1, x2, reg=0):
from mpmath import betainc, mpf
if x1 == x2:
return mpf(0)
else:
return betainc(a, b, x1, x2, reg)
###############################################################################
############################ COMPLETE BETA FUNCTION ##########################
###############################################################################
class beta(Function):
r"""
The beta integral is called the Eulerian integral of the first kind by
Legendre:
.. math::
\mathrm{B}(x,y) \int^{1}_{0} t^{x-1} (1-t)^{y-1} \mathrm{d}t.
Explanation
===========
The Beta function or Euler's first integral is closely associated
with the gamma function. The Beta function is often used in probability
theory and mathematical statistics. It satisfies properties like:
.. math::
\mathrm{B}(a,1) = \frac{1}{a} \\
\mathrm{B}(a,b) = \mathrm{B}(b,a) \\
\mathrm{B}(a,b) = \frac{\Gamma(a) \Gamma(b)}{\Gamma(a+b)}
Therefore for integral values of $a$ and $b$:
.. math::
\mathrm{B} = \frac{(a-1)! (b-1)!}{(a+b-1)!}
A special case of the Beta function when `x = y` is the
Central Beta function. It satisfies properties like:
.. math::
\mathrm{B}(x) = 2^{1 - 2x}\mathrm{B}(x, \frac{1}{2})
\mathrm{B}(x) = 2^{1 - 2x} cos(\pi x) \mathrm{B}(\frac{1}{2} - x, x)
\mathrm{B}(x) = \int_{0}^{1} \frac{t^x}{(1 + t)^{2x}} dt
\mathrm{B}(x) = \frac{2}{x} \prod_{n = 1}^{\infty} \frac{n(n + 2x)}{(n + x)^2}
Examples
========
>>> from sympy import I, pi
>>> from sympy.abc import x, y
The Beta function obeys the mirror symmetry:
>>> from sympy import beta, conjugate
>>> conjugate(beta(x, y))
beta(conjugate(x), conjugate(y))
Differentiation with respect to both $x$ and $y$ is supported:
>>> from sympy import beta, diff
>>> diff(beta(x, y), x)
(polygamma(0, x) - polygamma(0, x + y))*beta(x, y)
>>> diff(beta(x, y), y)
(polygamma(0, y) - polygamma(0, x + y))*beta(x, y)
>>> diff(beta(x), x)
2*(polygamma(0, x) - polygamma(0, 2*x))*beta(x, x)
We can numerically evaluate the Beta function to
arbitrary precision for any complex numbers x and y:
>>> from sympy import beta
>>> beta(pi).evalf(40)
0.02671848900111377452242355235388489324562
>>> beta(1 + I).evalf(20)
-0.2112723729365330143 - 0.7655283165378005676*I
See Also
========
gamma: Gamma function.
uppergamma: Upper incomplete gamma function.
lowergamma: Lower incomplete gamma function.
polygamma: Polygamma function.
loggamma: Log Gamma function.
digamma: Digamma function.
trigamma: Trigamma function.
References
==========
.. [1] https://en.wikipedia.org/wiki/Beta_function
.. [2] https://mathworld.wolfram.com/BetaFunction.html
.. [3] https://dlmf.nist.gov/5.12
"""
unbranched = True
def fdiff(self, argindex):
x, y = self.args
if argindex == 1:
# Diff wrt x
return beta(x, y)*(digamma(x) - digamma(x + y))
elif argindex == 2:
# Diff wrt y
return beta(x, y)*(digamma(y) - digamma(x + y))
else:
raise ArgumentIndexError(self, argindex)
@classmethod
def eval(cls, x, y=None):
if y is None:
return beta(x, x)
if x.is_Number and y.is_Number:
return beta(x, y, evaluate=False).doit()
def doit(self, **hints):
x = xold = self.args[0]
# Deal with unevaluated single argument beta
single_argument = len(self.args) == 1
y = yold = self.args[0] if single_argument else self.args[1]
if hints.get('deep', True):
x = x.doit(**hints)
y = y.doit(**hints)
if y.is_zero or x.is_zero:
return S.ComplexInfinity
if y is S.One:
return 1/x
if x is S.One:
return 1/y
if y == x + 1:
return 1/(x*y*catalan(x))
s = x + y
if (s.is_integer and s.is_negative and x.is_integer is False and
y.is_integer is False):
return S.Zero
if x == xold and y == yold and not single_argument:
return self
return beta(x, y)
def _eval_expand_func(self, **hints):
x, y = self.args
return gamma(x)*gamma(y) / gamma(x + y)
def _eval_is_real(self):
return self.args[0].is_real and self.args[1].is_real
def _eval_conjugate(self):
return self.func(self.args[0].conjugate(), self.args[1].conjugate())
def _eval_rewrite_as_gamma(self, x, y, piecewise=True, **kwargs):
return self._eval_expand_func(**kwargs)
def _eval_rewrite_as_Integral(self, x, y, **kwargs):
from sympy.integrals.integrals import Integral
t = Dummy(uniquely_named_symbol('t', [x, y]).name)
return Integral(t**(x - 1)*(1 - t)**(y - 1), (t, 0, 1))
###############################################################################
########################## INCOMPLETE BETA FUNCTION ###########################
###############################################################################
class betainc(Function):
r"""
The Generalized Incomplete Beta function is defined as
.. math::
\mathrm{B}_{(x_1, x_2)}(a, b) = \int_{x_1}^{x_2} t^{a - 1} (1 - t)^{b - 1} dt
The Incomplete Beta function is a special case
of the Generalized Incomplete Beta function :
.. math:: \mathrm{B}_z (a, b) = \mathrm{B}_{(0, z)}(a, b)
The Incomplete Beta function satisfies :
.. math:: \mathrm{B}_z (a, b) = (-1)^a \mathrm{B}_{\frac{z}{z - 1}} (a, 1 - a - b)
The Beta function is a special case of the Incomplete Beta function :
.. math:: \mathrm{B}(a, b) = \mathrm{B}_{1}(a, b)
Examples
========
>>> from sympy import betainc, symbols, conjugate
>>> a, b, x, x1, x2 = symbols('a b x x1 x2')
The Generalized Incomplete Beta function is given by:
>>> betainc(a, b, x1, x2)
betainc(a, b, x1, x2)
The Incomplete Beta function can be obtained as follows:
>>> betainc(a, b, 0, x)
betainc(a, b, 0, x)
The Incomplete Beta function obeys the mirror symmetry:
>>> conjugate(betainc(a, b, x1, x2))
betainc(conjugate(a), conjugate(b), conjugate(x1), conjugate(x2))
We can numerically evaluate the Incomplete Beta function to
arbitrary precision for any complex numbers a, b, x1 and x2:
>>> from sympy import betainc, I
>>> betainc(2, 3, 4, 5).evalf(10)
56.08333333
>>> betainc(0.75, 1 - 4*I, 0, 2 + 3*I).evalf(25)
0.2241657956955709603655887 + 0.3619619242700451992411724*I
The Generalized Incomplete Beta function can be expressed
in terms of the Generalized Hypergeometric function.
>>> from sympy import hyper
>>> betainc(a, b, x1, x2).rewrite(hyper)
(-x1**a*hyper((a, 1 - b), (a + 1,), x1) + x2**a*hyper((a, 1 - b), (a + 1,), x2))/a
See Also
========
beta: Beta function
hyper: Generalized Hypergeometric function
References
==========
.. [1] https://en.wikipedia.org/wiki/Beta_function#Incomplete_beta_function
.. [2] https://dlmf.nist.gov/8.17
.. [3] https://functions.wolfram.com/GammaBetaErf/Beta4/
.. [4] https://functions.wolfram.com/GammaBetaErf/BetaRegularized4/02/
"""
nargs = 4
unbranched = True
def fdiff(self, argindex):
a, b, x1, x2 = self.args
if argindex == 3:
# Diff wrt x1
return -(1 - x1)**(b - 1)*x1**(a - 1)
elif argindex == 4:
# Diff wrt x2
return (1 - x2)**(b - 1)*x2**(a - 1)
else:
raise ArgumentIndexError(self, argindex)
def _eval_mpmath(self):
return betainc_mpmath_fix, self.args
def _eval_is_real(self):
if all(arg.is_real for arg in self.args):
return True
def _eval_conjugate(self):
return self.func(*map(conjugate, self.args))
def _eval_rewrite_as_Integral(self, a, b, x1, x2, **kwargs):
from sympy.integrals.integrals import Integral
t = Dummy(uniquely_named_symbol('t', [a, b, x1, x2]).name)
return Integral(t**(a - 1)*(1 - t)**(b - 1), (t, x1, x2))
def _eval_rewrite_as_hyper(self, a, b, x1, x2, **kwargs):
from sympy.functions.special.hyper import hyper
return (x2**a * hyper((a, 1 - b), (a + 1,), x2) - x1**a * hyper((a, 1 - b), (a + 1,), x1)) / a
###############################################################################
#################### REGULARIZED INCOMPLETE BETA FUNCTION #####################
###############################################################################
class betainc_regularized(Function):
r"""
The Generalized Regularized Incomplete Beta function is given by
.. math::
\mathrm{I}_{(x_1, x_2)}(a, b) = \frac{\mathrm{B}_{(x_1, x_2)}(a, b)}{\mathrm{B}(a, b)}
The Regularized Incomplete Beta function is a special case
of the Generalized Regularized Incomplete Beta function :
.. math:: \mathrm{I}_z (a, b) = \mathrm{I}_{(0, z)}(a, b)
The Regularized Incomplete Beta function is the cumulative distribution
function of the beta distribution.
Examples
========
>>> from sympy import betainc_regularized, symbols, conjugate
>>> a, b, x, x1, x2 = symbols('a b x x1 x2')
The Generalized Regularized Incomplete Beta
function is given by:
>>> betainc_regularized(a, b, x1, x2)
betainc_regularized(a, b, x1, x2)
The Regularized Incomplete Beta function
can be obtained as follows:
>>> betainc_regularized(a, b, 0, x)
betainc_regularized(a, b, 0, x)
The Regularized Incomplete Beta function
obeys the mirror symmetry:
>>> conjugate(betainc_regularized(a, b, x1, x2))
betainc_regularized(conjugate(a), conjugate(b), conjugate(x1), conjugate(x2))
We can numerically evaluate the Regularized Incomplete Beta function
to arbitrary precision for any complex numbers a, b, x1 and x2:
>>> from sympy import betainc_regularized, pi, E
>>> betainc_regularized(1, 2, 0, 0.25).evalf(10)
0.4375000000
>>> betainc_regularized(pi, E, 0, 1).evalf(5)
1.00000
The Generalized Regularized Incomplete Beta function can be
expressed in terms of the Generalized Hypergeometric function.
>>> from sympy import hyper
>>> betainc_regularized(a, b, x1, x2).rewrite(hyper)
(-x1**a*hyper((a, 1 - b), (a + 1,), x1) + x2**a*hyper((a, 1 - b), (a + 1,), x2))/(a*beta(a, b))
See Also
========
beta: Beta function
hyper: Generalized Hypergeometric function
References
==========
.. [1] https://en.wikipedia.org/wiki/Beta_function#Incomplete_beta_function
.. [2] https://dlmf.nist.gov/8.17
.. [3] https://functions.wolfram.com/GammaBetaErf/Beta4/
.. [4] https://functions.wolfram.com/GammaBetaErf/BetaRegularized4/02/
"""
nargs = 4
unbranched = True
def __new__(cls, a, b, x1, x2):
return Function.__new__(cls, a, b, x1, x2)
def _eval_mpmath(self):
return betainc_mpmath_fix, (*self.args, S(1))
def fdiff(self, argindex):
a, b, x1, x2 = self.args
if argindex == 3:
# Diff wrt x1
return -(1 - x1)**(b - 1)*x1**(a - 1) / beta(a, b)
elif argindex == 4:
# Diff wrt x2
return (1 - x2)**(b - 1)*x2**(a - 1) / beta(a, b)
else:
raise ArgumentIndexError(self, argindex)
def _eval_is_real(self):
if all(arg.is_real for arg in self.args):
return True
def _eval_conjugate(self):
return self.func(*map(conjugate, self.args))
def _eval_rewrite_as_Integral(self, a, b, x1, x2, **kwargs):
from sympy.integrals.integrals import Integral
t = Dummy(uniquely_named_symbol('t', [a, b, x1, x2]).name)
integrand = t**(a - 1)*(1 - t)**(b - 1)
expr = Integral(integrand, (t, x1, x2))
return expr / Integral(integrand, (t, 0, 1))
def _eval_rewrite_as_hyper(self, a, b, x1, x2, **kwargs):
from sympy.functions.special.hyper import hyper
expr = (x2**a * hyper((a, 1 - b), (a + 1,), x2) - x1**a * hyper((a, 1 - b), (a + 1,), x1)) / a
return expr / beta(a, b)
PK ]ZZZPXl�' �' # sympy/functions/special/bsplines.pyfrom sympy.core import S, sympify
from sympy.core.symbol import (Dummy, symbols)
from sympy.functions import Piecewise, piecewise_fold
from sympy.logic.boolalg import And
from sympy.sets.sets import Interval
from functools import lru_cache
def _ivl(cond, x):
"""return the interval corresponding to the condition
Conditions in spline's Piecewise give the range over
which an expression is valid like (lo <= x) & (x <= hi).
This function returns (lo, hi).
"""
if isinstance(cond, And) and len(cond.args) == 2:
a, b = cond.args
if a.lts == x:
a, b = b, a
return a.lts, b.gts
raise TypeError('unexpected cond type: %s' % cond)
def _add_splines(c, b1, d, b2, x):
"""Construct c*b1 + d*b2."""
if S.Zero in (b1, c):
rv = piecewise_fold(d * b2)
elif S.Zero in (b2, d):
rv = piecewise_fold(c * b1)
else:
new_args = []
# Just combining the Piecewise without any fancy optimization
p1 = piecewise_fold(c * b1)
p2 = piecewise_fold(d * b2)
# Search all Piecewise arguments except (0, True)
p2args = list(p2.args[:-1])
# This merging algorithm assumes the conditions in
# p1 and p2 are sorted
for arg in p1.args[:-1]:
expr = arg.expr
cond = arg.cond
lower = _ivl(cond, x)[0]
# Check p2 for matching conditions that can be merged
for i, arg2 in enumerate(p2args):
expr2 = arg2.expr
cond2 = arg2.cond
lower_2, upper_2 = _ivl(cond2, x)
if cond2 == cond:
# Conditions match, join expressions
expr += expr2
# Remove matching element
del p2args[i]
# No need to check the rest
break
elif lower_2 < lower and upper_2 <= lower:
# Check if arg2 condition smaller than arg1,
# add to new_args by itself (no match expected
# in p1)
new_args.append(arg2)
del p2args[i]
break
# Checked all, add expr and cond
new_args.append((expr, cond))
# Add remaining items from p2args
new_args.extend(p2args)
# Add final (0, True)
new_args.append((0, True))
rv = Piecewise(*new_args, evaluate=False)
return rv.expand()
@lru_cache(maxsize=128)
def bspline_basis(d, knots, n, x):
"""
The $n$-th B-spline at $x$ of degree $d$ with knots.
Explanation
===========
B-Splines are piecewise polynomials of degree $d$. They are defined on a
set of knots, which is a sequence of integers or floats.
Examples
========
The 0th degree splines have a value of 1 on a single interval:
>>> from sympy import bspline_basis
>>> from sympy.abc import x
>>> d = 0
>>> knots = tuple(range(5))
>>> bspline_basis(d, knots, 0, x)
Piecewise((1, (x >= 0) & (x <= 1)), (0, True))
For a given ``(d, knots)`` there are ``len(knots)-d-1`` B-splines
defined, that are indexed by ``n`` (starting at 0).
Here is an example of a cubic B-spline:
>>> bspline_basis(3, tuple(range(5)), 0, x)
Piecewise((x**3/6, (x >= 0) & (x <= 1)),
(-x**3/2 + 2*x**2 - 2*x + 2/3,
(x >= 1) & (x <= 2)),
(x**3/2 - 4*x**2 + 10*x - 22/3,
(x >= 2) & (x <= 3)),
(-x**3/6 + 2*x**2 - 8*x + 32/3,
(x >= 3) & (x <= 4)),
(0, True))
By repeating knot points, you can introduce discontinuities in the
B-splines and their derivatives:
>>> d = 1
>>> knots = (0, 0, 2, 3, 4)
>>> bspline_basis(d, knots, 0, x)
Piecewise((1 - x/2, (x >= 0) & (x <= 2)), (0, True))
It is quite time consuming to construct and evaluate B-splines. If
you need to evaluate a B-spline many times, it is best to lambdify them
first:
>>> from sympy import lambdify
>>> d = 3
>>> knots = tuple(range(10))
>>> b0 = bspline_basis(d, knots, 0, x)
>>> f = lambdify(x, b0)
>>> y = f(0.5)
Parameters
==========
d : integer
degree of bspline
knots : list of integer values
list of knots points of bspline
n : integer
$n$-th B-spline
x : symbol
See Also
========
bspline_basis_set
References
==========
.. [1] https://en.wikipedia.org/wiki/B-spline
"""
# make sure x has no assumptions so conditions don't evaluate
xvar = x
x = Dummy()
knots = tuple(sympify(k) for k in knots)
d = int(d)
n = int(n)
n_knots = len(knots)
n_intervals = n_knots - 1
if n + d + 1 > n_intervals:
raise ValueError("n + d + 1 must not exceed len(knots) - 1")
if d == 0:
result = Piecewise(
(S.One, Interval(knots[n], knots[n + 1]).contains(x)), (0, True)
)
elif d > 0:
denom = knots[n + d + 1] - knots[n + 1]
if denom != S.Zero:
B = (knots[n + d + 1] - x) / denom
b2 = bspline_basis(d - 1, knots, n + 1, x)
else:
b2 = B = S.Zero
denom = knots[n + d] - knots[n]
if denom != S.Zero:
A = (x - knots[n]) / denom
b1 = bspline_basis(d - 1, knots, n, x)
else:
b1 = A = S.Zero
result = _add_splines(A, b1, B, b2, x)
else:
raise ValueError("degree must be non-negative: %r" % n)
# return result with user-given x
return result.xreplace({x: xvar})
def bspline_basis_set(d, knots, x):
"""
Return the ``len(knots)-d-1`` B-splines at *x* of degree *d*
with *knots*.
Explanation
===========
This function returns a list of piecewise polynomials that are the
``len(knots)-d-1`` B-splines of degree *d* for the given knots.
This function calls ``bspline_basis(d, knots, n, x)`` for different
values of *n*.
Examples
========
>>> from sympy import bspline_basis_set
>>> from sympy.abc import x
>>> d = 2
>>> knots = range(5)
>>> splines = bspline_basis_set(d, knots, x)
>>> splines
[Piecewise((x**2/2, (x >= 0) & (x <= 1)),
(-x**2 + 3*x - 3/2, (x >= 1) & (x <= 2)),
(x**2/2 - 3*x + 9/2, (x >= 2) & (x <= 3)),
(0, True)),
Piecewise((x**2/2 - x + 1/2, (x >= 1) & (x <= 2)),
(-x**2 + 5*x - 11/2, (x >= 2) & (x <= 3)),
(x**2/2 - 4*x + 8, (x >= 3) & (x <= 4)),
(0, True))]
Parameters
==========
d : integer
degree of bspline
knots : list of integers
list of knots points of bspline
x : symbol
See Also
========
bspline_basis
"""
n_splines = len(knots) - d - 1
return [bspline_basis(d, tuple(knots), i, x) for i in range(n_splines)]
def interpolating_spline(d, x, X, Y):
"""
Return spline of degree *d*, passing through the given *X*
and *Y* values.
Explanation
===========
This function returns a piecewise function such that each part is
a polynomial of degree not greater than *d*. The value of *d*
must be 1 or greater and the values of *X* must be strictly
increasing.
Examples
========
>>> from sympy import interpolating_spline
>>> from sympy.abc import x
>>> interpolating_spline(1, x, [1, 2, 4, 7], [3, 6, 5, 7])
Piecewise((3*x, (x >= 1) & (x <= 2)),
(7 - x/2, (x >= 2) & (x <= 4)),
(2*x/3 + 7/3, (x >= 4) & (x <= 7)))
>>> interpolating_spline(3, x, [-2, 0, 1, 3, 4], [4, 2, 1, 1, 3])
Piecewise((7*x**3/117 + 7*x**2/117 - 131*x/117 + 2, (x >= -2) & (x <= 1)),
(10*x**3/117 - 2*x**2/117 - 122*x/117 + 77/39, (x >= 1) & (x <= 4)))
Parameters
==========
d : integer
Degree of Bspline strictly greater than equal to one
x : symbol
X : list of strictly increasing real values
list of X coordinates through which the spline passes
Y : list of real values
list of corresponding Y coordinates through which the spline passes
See Also
========
bspline_basis_set, interpolating_poly
"""
from sympy.solvers.solveset import linsolve
from sympy.matrices.dense import Matrix
# Input sanitization
d = sympify(d)
if not (d.is_Integer and d.is_positive):
raise ValueError("Spline degree must be a positive integer, not %s." % d)
if len(X) != len(Y):
raise ValueError("Number of X and Y coordinates must be the same.")
if len(X) < d + 1:
raise ValueError("Degree must be less than the number of control points.")
if not all(a < b for a, b in zip(X, X[1:])):
raise ValueError("The x-coordinates must be strictly increasing.")
X = [sympify(i) for i in X]
# Evaluating knots value
if d.is_odd:
j = (d + 1) // 2
interior_knots = X[j:-j]
else:
j = d // 2
interior_knots = [
(a + b)/2 for a, b in zip(X[j : -j - 1], X[j + 1 : -j])
]
knots = [X[0]] * (d + 1) + list(interior_knots) + [X[-1]] * (d + 1)
basis = bspline_basis_set(d, knots, x)
A = [[b.subs(x, v) for b in basis] for v in X]
coeff = linsolve((Matrix(A), Matrix(Y)), symbols("c0:{}".format(len(X)), cls=Dummy))
coeff = list(coeff)[0]
intervals = {c for b in basis for (e, c) in b.args if c != True}
# Sorting the intervals
# ival contains the end-points of each interval
ival = [_ivl(c, x) for c in intervals]
com = zip(ival, intervals)
com = sorted(com, key=lambda x: x[0])
intervals = [y for x, y in com]
basis_dicts = [{c: e for (e, c) in b.args} for b in basis]
spline = []
for i in intervals:
piece = sum(
[c * d.get(i, S.Zero) for (c, d) in zip(coeff, basis_dicts)], S.Zero
)
spline.append((piece, i))
return Piecewise(*spline)
PK ]ZZZ=v
��M �M * sympy/functions/special/delta_functions.pyfrom sympy.core import S, diff
from sympy.core.function import Function, ArgumentIndexError
from sympy.core.logic import fuzzy_not
from sympy.core.relational import Eq, Ne
from sympy.functions.elementary.complexes import im, sign
from sympy.functions.elementary.piecewise import Piecewise
from sympy.polys.polyerrors import PolynomialError
from sympy.polys.polyroots import roots
from sympy.utilities.misc import filldedent
###############################################################################
################################ DELTA FUNCTION ###############################
###############################################################################
class DiracDelta(Function):
r"""
The DiracDelta function and its derivatives.
Explanation
===========
DiracDelta is not an ordinary function. It can be rigorously defined either
as a distribution or as a measure.
DiracDelta only makes sense in definite integrals, and in particular,
integrals of the form ``Integral(f(x)*DiracDelta(x - x0), (x, a, b))``,
where it equals ``f(x0)`` if ``a <= x0 <= b`` and ``0`` otherwise. Formally,
DiracDelta acts in some ways like a function that is ``0`` everywhere except
at ``0``, but in many ways it also does not. It can often be useful to treat
DiracDelta in formal ways, building up and manipulating expressions with
delta functions (which may eventually be integrated), but care must be taken
to not treat it as a real function. SymPy's ``oo`` is similar. It only
truly makes sense formally in certain contexts (such as integration limits),
but SymPy allows its use everywhere, and it tries to be consistent with
operations on it (like ``1/oo``), but it is easy to get into trouble and get
wrong results if ``oo`` is treated too much like a number. Similarly, if
DiracDelta is treated too much like a function, it is easy to get wrong or
nonsensical results.
DiracDelta function has the following properties:
1) $\frac{d}{d x} \theta(x) = \delta(x)$
2) $\int_{-\infty}^\infty \delta(x - a)f(x)\, dx = f(a)$ and $\int_{a-
\epsilon}^{a+\epsilon} \delta(x - a)f(x)\, dx = f(a)$
3) $\delta(x) = 0$ for all $x \neq 0$
4) $\delta(g(x)) = \sum_i \frac{\delta(x - x_i)}{\|g'(x_i)\|}$ where $x_i$
are the roots of $g$
5) $\delta(-x) = \delta(x)$
Derivatives of ``k``-th order of DiracDelta have the following properties:
6) $\delta(x, k) = 0$ for all $x \neq 0$
7) $\delta(-x, k) = -\delta(x, k)$ for odd $k$
8) $\delta(-x, k) = \delta(x, k)$ for even $k$
Examples
========
>>> from sympy import DiracDelta, diff, pi
>>> from sympy.abc import x, y
>>> DiracDelta(x)
DiracDelta(x)
>>> DiracDelta(1)
0
>>> DiracDelta(-1)
0
>>> DiracDelta(pi)
0
>>> DiracDelta(x - 4).subs(x, 4)
DiracDelta(0)
>>> diff(DiracDelta(x))
DiracDelta(x, 1)
>>> diff(DiracDelta(x - 1), x, 2)
DiracDelta(x - 1, 2)
>>> diff(DiracDelta(x**2 - 1), x, 2)
2*(2*x**2*DiracDelta(x**2 - 1, 2) + DiracDelta(x**2 - 1, 1))
>>> DiracDelta(3*x).is_simple(x)
True
>>> DiracDelta(x**2).is_simple(x)
False
>>> DiracDelta((x**2 - 1)*y).expand(diracdelta=True, wrt=x)
DiracDelta(x - 1)/(2*Abs(y)) + DiracDelta(x + 1)/(2*Abs(y))
See Also
========
Heaviside
sympy.simplify.simplify.simplify, is_simple
sympy.functions.special.tensor_functions.KroneckerDelta
References
==========
.. [1] https://mathworld.wolfram.com/DeltaFunction.html
"""
is_real = True
def fdiff(self, argindex=1):
"""
Returns the first derivative of a DiracDelta Function.
Explanation
===========
The difference between ``diff()`` and ``fdiff()`` is: ``diff()`` is the
user-level function and ``fdiff()`` is an object method. ``fdiff()`` is
a convenience method available in the ``Function`` class. It returns
the derivative of the function without considering the chain rule.
``diff(function, x)`` calls ``Function._eval_derivative`` which in turn
calls ``fdiff()`` internally to compute the derivative of the function.
Examples
========
>>> from sympy import DiracDelta, diff
>>> from sympy.abc import x
>>> DiracDelta(x).fdiff()
DiracDelta(x, 1)
>>> DiracDelta(x, 1).fdiff()
DiracDelta(x, 2)
>>> DiracDelta(x**2 - 1).fdiff()
DiracDelta(x**2 - 1, 1)
>>> diff(DiracDelta(x, 1)).fdiff()
DiracDelta(x, 3)
Parameters
==========
argindex : integer
degree of derivative
"""
if argindex == 1:
#I didn't know if there is a better way to handle default arguments
k = 0
if len(self.args) > 1:
k = self.args[1]
return self.func(self.args[0], k + 1)
else:
raise ArgumentIndexError(self, argindex)
@classmethod
def eval(cls, arg, k=S.Zero):
"""
Returns a simplified form or a value of DiracDelta depending on the
argument passed by the DiracDelta object.
Explanation
===========
The ``eval()`` method is automatically called when the ``DiracDelta``
class is about to be instantiated and it returns either some simplified
instance or the unevaluated instance depending on the argument passed.
In other words, ``eval()`` method is not needed to be called explicitly,
it is being called and evaluated once the object is called.
Examples
========
>>> from sympy import DiracDelta, S
>>> from sympy.abc import x
>>> DiracDelta(x)
DiracDelta(x)
>>> DiracDelta(-x, 1)
-DiracDelta(x, 1)
>>> DiracDelta(1)
0
>>> DiracDelta(5, 1)
0
>>> DiracDelta(0)
DiracDelta(0)
>>> DiracDelta(-1)
0
>>> DiracDelta(S.NaN)
nan
>>> DiracDelta(x - 100).subs(x, 5)
0
>>> DiracDelta(x - 100).subs(x, 100)
DiracDelta(0)
Parameters
==========
k : integer
order of derivative
arg : argument passed to DiracDelta
"""
if not k.is_Integer or k.is_negative:
raise ValueError("Error: the second argument of DiracDelta must be \
a non-negative integer, %s given instead." % (k,))
if arg is S.NaN:
return S.NaN
if arg.is_nonzero:
return S.Zero
if fuzzy_not(im(arg).is_zero):
raise ValueError(filldedent('''
Function defined only for Real Values.
Complex part: %s found in %s .''' % (
repr(im(arg)), repr(arg))))
c, nc = arg.args_cnc()
if c and c[0] is S.NegativeOne:
# keep this fast and simple instead of using
# could_extract_minus_sign
if k.is_odd:
return -cls(-arg, k)
elif k.is_even:
return cls(-arg, k) if k else cls(-arg)
elif k.is_zero:
return cls(arg, evaluate=False)
def _eval_expand_diracdelta(self, **hints):
"""
Compute a simplified representation of the function using
property number 4. Pass ``wrt`` as a hint to expand the expression
with respect to a particular variable.
Explanation
===========
``wrt`` is:
- a variable with respect to which a DiracDelta expression will
get expanded.
Examples
========
>>> from sympy import DiracDelta
>>> from sympy.abc import x, y
>>> DiracDelta(x*y).expand(diracdelta=True, wrt=x)
DiracDelta(x)/Abs(y)
>>> DiracDelta(x*y).expand(diracdelta=True, wrt=y)
DiracDelta(y)/Abs(x)
>>> DiracDelta(x**2 + x - 2).expand(diracdelta=True, wrt=x)
DiracDelta(x - 1)/3 + DiracDelta(x + 2)/3
See Also
========
is_simple, Diracdelta
"""
wrt = hints.get('wrt', None)
if wrt is None:
free = self.free_symbols
if len(free) == 1:
wrt = free.pop()
else:
raise TypeError(filldedent('''
When there is more than 1 free symbol or variable in the expression,
the 'wrt' keyword is required as a hint to expand when using the
DiracDelta hint.'''))
if not self.args[0].has(wrt) or (len(self.args) > 1 and self.args[1] != 0 ):
return self
try:
argroots = roots(self.args[0], wrt)
result = 0
valid = True
darg = abs(diff(self.args[0], wrt))
for r, m in argroots.items():
if r.is_real is not False and m == 1:
result += self.func(wrt - r)/darg.subs(wrt, r)
else:
# don't handle non-real and if m != 1 then
# a polynomial will have a zero in the derivative (darg)
# at r
valid = False
break
if valid:
return result
except PolynomialError:
pass
return self
def is_simple(self, x):
"""
Tells whether the argument(args[0]) of DiracDelta is a linear
expression in *x*.
Examples
========
>>> from sympy import DiracDelta, cos
>>> from sympy.abc import x, y
>>> DiracDelta(x*y).is_simple(x)
True
>>> DiracDelta(x*y).is_simple(y)
True
>>> DiracDelta(x**2 + x - 2).is_simple(x)
False
>>> DiracDelta(cos(x)).is_simple(x)
False
Parameters
==========
x : can be a symbol
See Also
========
sympy.simplify.simplify.simplify, DiracDelta
"""
p = self.args[0].as_poly(x)
if p:
return p.degree() == 1
return False
def _eval_rewrite_as_Piecewise(self, *args, **kwargs):
"""
Represents DiracDelta in a piecewise form.
Examples
========
>>> from sympy import DiracDelta, Piecewise, Symbol
>>> x = Symbol('x')
>>> DiracDelta(x).rewrite(Piecewise)
Piecewise((DiracDelta(0), Eq(x, 0)), (0, True))
>>> DiracDelta(x - 5).rewrite(Piecewise)
Piecewise((DiracDelta(0), Eq(x, 5)), (0, True))
>>> DiracDelta(x**2 - 5).rewrite(Piecewise)
Piecewise((DiracDelta(0), Eq(x**2, 5)), (0, True))
>>> DiracDelta(x - 5, 4).rewrite(Piecewise)
DiracDelta(x - 5, 4)
"""
if len(args) == 1:
return Piecewise((DiracDelta(0), Eq(args[0], 0)), (0, True))
def _eval_rewrite_as_SingularityFunction(self, *args, **kwargs):
"""
Returns the DiracDelta expression written in the form of Singularity
Functions.
"""
from sympy.solvers import solve
from sympy.functions.special.singularity_functions import SingularityFunction
if self == DiracDelta(0):
return SingularityFunction(0, 0, -1)
if self == DiracDelta(0, 1):
return SingularityFunction(0, 0, -2)
free = self.free_symbols
if len(free) == 1:
x = (free.pop())
if len(args) == 1:
return SingularityFunction(x, solve(args[0], x)[0], -1)
return SingularityFunction(x, solve(args[0], x)[0], -args[1] - 1)
else:
# I don't know how to handle the case for DiracDelta expressions
# having arguments with more than one variable.
raise TypeError(filldedent('''
rewrite(SingularityFunction) does not support
arguments with more that one variable.'''))
###############################################################################
############################## HEAVISIDE FUNCTION #############################
###############################################################################
class Heaviside(Function):
r"""
Heaviside step function.
Explanation
===========
The Heaviside step function has the following properties:
1) $\frac{d}{d x} \theta(x) = \delta(x)$
2) $\theta(x) = \begin{cases} 0 & \text{for}\: x < 0 \\ \frac{1}{2} &
\text{for}\: x = 0 \\1 & \text{for}\: x > 0 \end{cases}$
3) $\frac{d}{d x} \max(x, 0) = \theta(x)$
Heaviside(x) is printed as $\theta(x)$ with the SymPy LaTeX printer.
The value at 0 is set differently in different fields. SymPy uses 1/2,
which is a convention from electronics and signal processing, and is
consistent with solving improper integrals by Fourier transform and
convolution.
To specify a different value of Heaviside at ``x=0``, a second argument
can be given. Using ``Heaviside(x, nan)`` gives an expression that will
evaluate to nan for x=0.
.. versionchanged:: 1.9 ``Heaviside(0)`` now returns 1/2 (before: undefined)
Examples
========
>>> from sympy import Heaviside, nan
>>> from sympy.abc import x
>>> Heaviside(9)
1
>>> Heaviside(-9)
0
>>> Heaviside(0)
1/2
>>> Heaviside(0, nan)
nan
>>> (Heaviside(x) + 1).replace(Heaviside(x), Heaviside(x, 1))
Heaviside(x, 1) + 1
See Also
========
DiracDelta
References
==========
.. [1] https://mathworld.wolfram.com/HeavisideStepFunction.html
.. [2] https://dlmf.nist.gov/1.16#iv
"""
is_real = True
def fdiff(self, argindex=1):
"""
Returns the first derivative of a Heaviside Function.
Examples
========
>>> from sympy import Heaviside, diff
>>> from sympy.abc import x
>>> Heaviside(x).fdiff()
DiracDelta(x)
>>> Heaviside(x**2 - 1).fdiff()
DiracDelta(x**2 - 1)
>>> diff(Heaviside(x)).fdiff()
DiracDelta(x, 1)
Parameters
==========
argindex : integer
order of derivative
"""
if argindex == 1:
return DiracDelta(self.args[0])
else:
raise ArgumentIndexError(self, argindex)
def __new__(cls, arg, H0=S.Half, **options):
if isinstance(H0, Heaviside) and len(H0.args) == 1:
H0 = S.Half
return super(cls, cls).__new__(cls, arg, H0, **options)
@property
def pargs(self):
"""Args without default S.Half"""
args = self.args
if args[1] is S.Half:
args = args[:1]
return args
@classmethod
def eval(cls, arg, H0=S.Half):
"""
Returns a simplified form or a value of Heaviside depending on the
argument passed by the Heaviside object.
Explanation
===========
The ``eval()`` method is automatically called when the ``Heaviside``
class is about to be instantiated and it returns either some simplified
instance or the unevaluated instance depending on the argument passed.
In other words, ``eval()`` method is not needed to be called explicitly,
it is being called and evaluated once the object is called.
Examples
========
>>> from sympy import Heaviside, S
>>> from sympy.abc import x
>>> Heaviside(x)
Heaviside(x)
>>> Heaviside(19)
1
>>> Heaviside(0)
1/2
>>> Heaviside(0, 1)
1
>>> Heaviside(-5)
0
>>> Heaviside(S.NaN)
nan
>>> Heaviside(x - 100).subs(x, 5)
0
>>> Heaviside(x - 100).subs(x, 105)
1
Parameters
==========
arg : argument passed by Heaviside object
H0 : value of Heaviside(0)
"""
if arg.is_extended_negative:
return S.Zero
elif arg.is_extended_positive:
return S.One
elif arg.is_zero:
return H0
elif arg is S.NaN:
return S.NaN
elif fuzzy_not(im(arg).is_zero):
raise ValueError("Function defined only for Real Values. Complex part: %s found in %s ." % (repr(im(arg)), repr(arg)) )
def _eval_rewrite_as_Piecewise(self, arg, H0=None, **kwargs):
"""
Represents Heaviside in a Piecewise form.
Examples
========
>>> from sympy import Heaviside, Piecewise, Symbol, nan
>>> x = Symbol('x')
>>> Heaviside(x).rewrite(Piecewise)
Piecewise((0, x < 0), (1/2, Eq(x, 0)), (1, True))
>>> Heaviside(x,nan).rewrite(Piecewise)
Piecewise((0, x < 0), (nan, Eq(x, 0)), (1, True))
>>> Heaviside(x - 5).rewrite(Piecewise)
Piecewise((0, x < 5), (1/2, Eq(x, 5)), (1, True))
>>> Heaviside(x**2 - 1).rewrite(Piecewise)
Piecewise((0, x**2 < 1), (1/2, Eq(x**2, 1)), (1, True))
"""
if H0 == 0:
return Piecewise((0, arg <= 0), (1, True))
if H0 == 1:
return Piecewise((0, arg < 0), (1, True))
return Piecewise((0, arg < 0), (H0, Eq(arg, 0)), (1, True))
def _eval_rewrite_as_sign(self, arg, H0=S.Half, **kwargs):
"""
Represents the Heaviside function in the form of sign function.
Explanation
===========
The value of Heaviside(0) must be 1/2 for rewriting as sign to be
strictly equivalent. For easier usage, we also allow this rewriting
when Heaviside(0) is undefined.
Examples
========
>>> from sympy import Heaviside, Symbol, sign, nan
>>> x = Symbol('x', real=True)
>>> y = Symbol('y')
>>> Heaviside(x).rewrite(sign)
sign(x)/2 + 1/2
>>> Heaviside(x, 0).rewrite(sign)
Piecewise((sign(x)/2 + 1/2, Ne(x, 0)), (0, True))
>>> Heaviside(x, nan).rewrite(sign)
Piecewise((sign(x)/2 + 1/2, Ne(x, 0)), (nan, True))
>>> Heaviside(x - 2).rewrite(sign)
sign(x - 2)/2 + 1/2
>>> Heaviside(x**2 - 2*x + 1).rewrite(sign)
sign(x**2 - 2*x + 1)/2 + 1/2
>>> Heaviside(y).rewrite(sign)
Heaviside(y)
>>> Heaviside(y**2 - 2*y + 1).rewrite(sign)
Heaviside(y**2 - 2*y + 1)
See Also
========
sign
"""
if arg.is_extended_real:
pw1 = Piecewise(
((sign(arg) + 1)/2, Ne(arg, 0)),
(Heaviside(0, H0=H0), True))
pw2 = Piecewise(
((sign(arg) + 1)/2, Eq(Heaviside(0, H0=H0), S.Half)),
(pw1, True))
return pw2
def _eval_rewrite_as_SingularityFunction(self, args, H0=S.Half, **kwargs):
"""
Returns the Heaviside expression written in the form of Singularity
Functions.
"""
from sympy.solvers import solve
from sympy.functions.special.singularity_functions import SingularityFunction
if self == Heaviside(0):
return SingularityFunction(0, 0, 0)
free = self.free_symbols
if len(free) == 1:
x = (free.pop())
return SingularityFunction(x, solve(args, x)[0], 0)
# TODO
# ((x - 5)**3*Heaviside(x - 5)).rewrite(SingularityFunction) should output
# SingularityFunction(x, 5, 0) instead of (x - 5)**3*SingularityFunction(x, 5, 0)
else:
# I don't know how to handle the case for Heaviside expressions
# having arguments with more than one variable.
raise TypeError(filldedent('''
rewrite(SingularityFunction) does not
support arguments with more that one variable.'''))
PK ]ZZZ=D�,: ,: - sympy/functions/special/elliptic_integrals.py""" Elliptic Integrals. """
from sympy.core import S, pi, I, Rational
from sympy.core.function import Function, ArgumentIndexError
from sympy.core.symbol import Dummy,uniquely_named_symbol
from sympy.functions.elementary.complexes import sign
from sympy.functions.elementary.hyperbolic import atanh
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.elementary.trigonometric import sin, tan
from sympy.functions.special.gamma_functions import gamma
from sympy.functions.special.hyper import hyper, meijerg
class elliptic_k(Function):
r"""
The complete elliptic integral of the first kind, defined by
.. math:: K(m) = F\left(\tfrac{\pi}{2}\middle| m\right)
where $F\left(z\middle| m\right)$ is the Legendre incomplete
elliptic integral of the first kind.
Explanation
===========
The function $K(m)$ is a single-valued function on the complex
plane with branch cut along the interval $(1, \infty)$.
Note that our notation defines the incomplete elliptic integral
in terms of the parameter $m$ instead of the elliptic modulus
(eccentricity) $k$.
In this case, the parameter $m$ is defined as $m=k^2$.
Examples
========
>>> from sympy import elliptic_k, I
>>> from sympy.abc import m
>>> elliptic_k(0)
pi/2
>>> elliptic_k(1.0 + I)
1.50923695405127 + 0.625146415202697*I
>>> elliptic_k(m).series(n=3)
pi/2 + pi*m/8 + 9*pi*m**2/128 + O(m**3)
See Also
========
elliptic_f
References
==========
.. [1] https://en.wikipedia.org/wiki/Elliptic_integrals
.. [2] https://functions.wolfram.com/EllipticIntegrals/EllipticK
"""
@classmethod
def eval(cls, m):
if m.is_zero:
return pi*S.Half
elif m is S.Half:
return 8*pi**Rational(3, 2)/gamma(Rational(-1, 4))**2
elif m is S.One:
return S.ComplexInfinity
elif m is S.NegativeOne:
return gamma(Rational(1, 4))**2/(4*sqrt(2*pi))
elif m in (S.Infinity, S.NegativeInfinity, I*S.Infinity,
I*S.NegativeInfinity, S.ComplexInfinity):
return S.Zero
def fdiff(self, argindex=1):
m = self.args[0]
return (elliptic_e(m) - (1 - m)*elliptic_k(m))/(2*m*(1 - m))
def _eval_conjugate(self):
m = self.args[0]
if (m.is_real and (m - 1).is_positive) is False:
return self.func(m.conjugate())
def _eval_nseries(self, x, n, logx, cdir=0):
from sympy.simplify import hyperexpand
return hyperexpand(self.rewrite(hyper)._eval_nseries(x, n=n, logx=logx))
def _eval_rewrite_as_hyper(self, m, **kwargs):
return pi*S.Half*hyper((S.Half, S.Half), (S.One,), m)
def _eval_rewrite_as_meijerg(self, m, **kwargs):
return meijerg(((S.Half, S.Half), []), ((S.Zero,), (S.Zero,)), -m)/2
def _eval_is_zero(self):
m = self.args[0]
if m.is_infinite:
return True
def _eval_rewrite_as_Integral(self, *args, **kwargs):
from sympy.integrals.integrals import Integral
t = Dummy(uniquely_named_symbol('t', args).name)
m = self.args[0]
return Integral(1/sqrt(1 - m*sin(t)**2), (t, 0, pi/2))
class elliptic_f(Function):
r"""
The Legendre incomplete elliptic integral of the first
kind, defined by
.. math:: F\left(z\middle| m\right) =
\int_0^z \frac{dt}{\sqrt{1 - m \sin^2 t}}
Explanation
===========
This function reduces to a complete elliptic integral of
the first kind, $K(m)$, when $z = \pi/2$.
Note that our notation defines the incomplete elliptic integral
in terms of the parameter $m$ instead of the elliptic modulus
(eccentricity) $k$.
In this case, the parameter $m$ is defined as $m=k^2$.
Examples
========
>>> from sympy import elliptic_f, I
>>> from sympy.abc import z, m
>>> elliptic_f(z, m).series(z)
z + z**5*(3*m**2/40 - m/30) + m*z**3/6 + O(z**6)
>>> elliptic_f(3.0 + I/2, 1.0 + I)
2.909449841483 + 1.74720545502474*I
See Also
========
elliptic_k
References
==========
.. [1] https://en.wikipedia.org/wiki/Elliptic_integrals
.. [2] https://functions.wolfram.com/EllipticIntegrals/EllipticF
"""
@classmethod
def eval(cls, z, m):
if z.is_zero:
return S.Zero
if m.is_zero:
return z
k = 2*z/pi
if k.is_integer:
return k*elliptic_k(m)
elif m in (S.Infinity, S.NegativeInfinity):
return S.Zero
elif z.could_extract_minus_sign():
return -elliptic_f(-z, m)
def fdiff(self, argindex=1):
z, m = self.args
fm = sqrt(1 - m*sin(z)**2)
if argindex == 1:
return 1/fm
elif argindex == 2:
return (elliptic_e(z, m)/(2*m*(1 - m)) - elliptic_f(z, m)/(2*m) -
sin(2*z)/(4*(1 - m)*fm))
raise ArgumentIndexError(self, argindex)
def _eval_conjugate(self):
z, m = self.args
if (m.is_real and (m - 1).is_positive) is False:
return self.func(z.conjugate(), m.conjugate())
def _eval_rewrite_as_Integral(self, *args, **kwargs):
from sympy.integrals.integrals import Integral
t = Dummy(uniquely_named_symbol('t', args).name)
z, m = self.args[0], self.args[1]
return Integral(1/(sqrt(1 - m*sin(t)**2)), (t, 0, z))
def _eval_is_zero(self):
z, m = self.args
if z.is_zero:
return True
if m.is_extended_real and m.is_infinite:
return True
class elliptic_e(Function):
r"""
Called with two arguments $z$ and $m$, evaluates the
incomplete elliptic integral of the second kind, defined by
.. math:: E\left(z\middle| m\right) = \int_0^z \sqrt{1 - m \sin^2 t} dt
Called with a single argument $m$, evaluates the Legendre complete
elliptic integral of the second kind
.. math:: E(m) = E\left(\tfrac{\pi}{2}\middle| m\right)
Explanation
===========
The function $E(m)$ is a single-valued function on the complex
plane with branch cut along the interval $(1, \infty)$.
Note that our notation defines the incomplete elliptic integral
in terms of the parameter $m$ instead of the elliptic modulus
(eccentricity) $k$.
In this case, the parameter $m$ is defined as $m=k^2$.
Examples
========
>>> from sympy import elliptic_e, I
>>> from sympy.abc import z, m
>>> elliptic_e(z, m).series(z)
z + z**5*(-m**2/40 + m/30) - m*z**3/6 + O(z**6)
>>> elliptic_e(m).series(n=4)
pi/2 - pi*m/8 - 3*pi*m**2/128 - 5*pi*m**3/512 + O(m**4)
>>> elliptic_e(1 + I, 2 - I/2).n()
1.55203744279187 + 0.290764986058437*I
>>> elliptic_e(0)
pi/2
>>> elliptic_e(2.0 - I)
0.991052601328069 + 0.81879421395609*I
References
==========
.. [1] https://en.wikipedia.org/wiki/Elliptic_integrals
.. [2] https://functions.wolfram.com/EllipticIntegrals/EllipticE2
.. [3] https://functions.wolfram.com/EllipticIntegrals/EllipticE
"""
@classmethod
def eval(cls, m, z=None):
if z is not None:
z, m = m, z
k = 2*z/pi
if m.is_zero:
return z
if z.is_zero:
return S.Zero
elif k.is_integer:
return k*elliptic_e(m)
elif m in (S.Infinity, S.NegativeInfinity):
return S.ComplexInfinity
elif z.could_extract_minus_sign():
return -elliptic_e(-z, m)
else:
if m.is_zero:
return pi/2
elif m is S.One:
return S.One
elif m is S.Infinity:
return I*S.Infinity
elif m is S.NegativeInfinity:
return S.Infinity
elif m is S.ComplexInfinity:
return S.ComplexInfinity
def fdiff(self, argindex=1):
if len(self.args) == 2:
z, m = self.args
if argindex == 1:
return sqrt(1 - m*sin(z)**2)
elif argindex == 2:
return (elliptic_e(z, m) - elliptic_f(z, m))/(2*m)
else:
m = self.args[0]
if argindex == 1:
return (elliptic_e(m) - elliptic_k(m))/(2*m)
raise ArgumentIndexError(self, argindex)
def _eval_conjugate(self):
if len(self.args) == 2:
z, m = self.args
if (m.is_real and (m - 1).is_positive) is False:
return self.func(z.conjugate(), m.conjugate())
else:
m = self.args[0]
if (m.is_real and (m - 1).is_positive) is False:
return self.func(m.conjugate())
def _eval_nseries(self, x, n, logx, cdir=0):
from sympy.simplify import hyperexpand
if len(self.args) == 1:
return hyperexpand(self.rewrite(hyper)._eval_nseries(x, n=n, logx=logx))
return super()._eval_nseries(x, n=n, logx=logx)
def _eval_rewrite_as_hyper(self, *args, **kwargs):
if len(args) == 1:
m = args[0]
return (pi/2)*hyper((Rational(-1, 2), S.Half), (S.One,), m)
def _eval_rewrite_as_meijerg(self, *args, **kwargs):
if len(args) == 1:
m = args[0]
return -meijerg(((S.Half, Rational(3, 2)), []), \
((S.Zero,), (S.Zero,)), -m)/4
def _eval_rewrite_as_Integral(self, *args, **kwargs):
from sympy.integrals.integrals import Integral
z, m = (pi/2, self.args[0]) if len(self.args) == 1 else self.args
t = Dummy(uniquely_named_symbol('t', args).name)
return Integral(sqrt(1 - m*sin(t)**2), (t, 0, z))
class elliptic_pi(Function):
r"""
Called with three arguments $n$, $z$ and $m$, evaluates the
Legendre incomplete elliptic integral of the third kind, defined by
.. math:: \Pi\left(n; z\middle| m\right) = \int_0^z \frac{dt}
{\left(1 - n \sin^2 t\right) \sqrt{1 - m \sin^2 t}}
Called with two arguments $n$ and $m$, evaluates the complete
elliptic integral of the third kind:
.. math:: \Pi\left(n\middle| m\right) =
\Pi\left(n; \tfrac{\pi}{2}\middle| m\right)
Explanation
===========
Note that our notation defines the incomplete elliptic integral
in terms of the parameter $m$ instead of the elliptic modulus
(eccentricity) $k$.
In this case, the parameter $m$ is defined as $m=k^2$.
Examples
========
>>> from sympy import elliptic_pi, I
>>> from sympy.abc import z, n, m
>>> elliptic_pi(n, z, m).series(z, n=4)
z + z**3*(m/6 + n/3) + O(z**4)
>>> elliptic_pi(0.5 + I, 1.0 - I, 1.2)
2.50232379629182 - 0.760939574180767*I
>>> elliptic_pi(0, 0)
pi/2
>>> elliptic_pi(1.0 - I/3, 2.0 + I)
3.29136443417283 + 0.32555634906645*I
References
==========
.. [1] https://en.wikipedia.org/wiki/Elliptic_integrals
.. [2] https://functions.wolfram.com/EllipticIntegrals/EllipticPi3
.. [3] https://functions.wolfram.com/EllipticIntegrals/EllipticPi
"""
@classmethod
def eval(cls, n, m, z=None):
if z is not None:
n, z, m = n, m, z
if n.is_zero:
return elliptic_f(z, m)
elif n is S.One:
return (elliptic_f(z, m) +
(sqrt(1 - m*sin(z)**2)*tan(z) -
elliptic_e(z, m))/(1 - m))
k = 2*z/pi
if k.is_integer:
return k*elliptic_pi(n, m)
elif m.is_zero:
return atanh(sqrt(n - 1)*tan(z))/sqrt(n - 1)
elif n == m:
return (elliptic_f(z, n) - elliptic_pi(1, z, n) +
tan(z)/sqrt(1 - n*sin(z)**2))
elif n in (S.Infinity, S.NegativeInfinity):
return S.Zero
elif m in (S.Infinity, S.NegativeInfinity):
return S.Zero
elif z.could_extract_minus_sign():
return -elliptic_pi(n, -z, m)
if n.is_zero:
return elliptic_f(z, m)
if m.is_extended_real and m.is_infinite or \
n.is_extended_real and n.is_infinite:
return S.Zero
else:
if n.is_zero:
return elliptic_k(m)
elif n is S.One:
return S.ComplexInfinity
elif m.is_zero:
return pi/(2*sqrt(1 - n))
elif m == S.One:
return S.NegativeInfinity/sign(n - 1)
elif n == m:
return elliptic_e(n)/(1 - n)
elif n in (S.Infinity, S.NegativeInfinity):
return S.Zero
elif m in (S.Infinity, S.NegativeInfinity):
return S.Zero
if n.is_zero:
return elliptic_k(m)
if m.is_extended_real and m.is_infinite or \
n.is_extended_real and n.is_infinite:
return S.Zero
def _eval_conjugate(self):
if len(self.args) == 3:
n, z, m = self.args
if (n.is_real and (n - 1).is_positive) is False and \
(m.is_real and (m - 1).is_positive) is False:
return self.func(n.conjugate(), z.conjugate(), m.conjugate())
else:
n, m = self.args
return self.func(n.conjugate(), m.conjugate())
def fdiff(self, argindex=1):
if len(self.args) == 3:
n, z, m = self.args
fm, fn = sqrt(1 - m*sin(z)**2), 1 - n*sin(z)**2
if argindex == 1:
return (elliptic_e(z, m) + (m - n)*elliptic_f(z, m)/n +
(n**2 - m)*elliptic_pi(n, z, m)/n -
n*fm*sin(2*z)/(2*fn))/(2*(m - n)*(n - 1))
elif argindex == 2:
return 1/(fm*fn)
elif argindex == 3:
return (elliptic_e(z, m)/(m - 1) +
elliptic_pi(n, z, m) -
m*sin(2*z)/(2*(m - 1)*fm))/(2*(n - m))
else:
n, m = self.args
if argindex == 1:
return (elliptic_e(m) + (m - n)*elliptic_k(m)/n +
(n**2 - m)*elliptic_pi(n, m)/n)/(2*(m - n)*(n - 1))
elif argindex == 2:
return (elliptic_e(m)/(m - 1) + elliptic_pi(n, m))/(2*(n - m))
raise ArgumentIndexError(self, argindex)
def _eval_rewrite_as_Integral(self, *args, **kwargs):
from sympy.integrals.integrals import Integral
if len(self.args) == 2:
n, m, z = self.args[0], self.args[1], pi/2
else:
n, z, m = self.args
t = Dummy(uniquely_named_symbol('t', args).name)
return Integral(1/((1 - n*sin(t)**2)*sqrt(1 - m*sin(t)**2)), (t, 0, z))
PK ]ZZZ�]˺3 �3 * sympy/functions/special/error_functions.py""" This module contains various functions that are special cases
of incomplete gamma functions. It should probably be renamed. """
from sympy.core import EulerGamma # Must be imported from core, not core.numbers
from sympy.core.add import Add
from sympy.core.cache import cacheit
from sympy.core.function import Function, ArgumentIndexError, expand_mul
from sympy.core.numbers import I, pi, Rational
from sympy.core.relational import is_eq
from sympy.core.power import Pow
from sympy.core.singleton import S
from sympy.core.symbol import Dummy, uniquely_named_symbol
from sympy.core.sympify import sympify
from sympy.functions.combinatorial.factorials import factorial, factorial2, RisingFactorial
from sympy.functions.elementary.complexes import polar_lift, re, unpolarify
from sympy.functions.elementary.integers import ceiling, floor
from sympy.functions.elementary.miscellaneous import sqrt, root
from sympy.functions.elementary.exponential import exp, log, exp_polar
from sympy.functions.elementary.hyperbolic import cosh, sinh
from sympy.functions.elementary.trigonometric import cos, sin, sinc
from sympy.functions.special.hyper import hyper, meijerg
# TODO series expansions
# TODO see the "Note:" in Ei
# Helper function
def real_to_real_as_real_imag(self, deep=True, **hints):
if self.args[0].is_extended_real:
if deep:
hints['complex'] = False
return (self.expand(deep, **hints), S.Zero)
else:
return (self, S.Zero)
if deep:
x, y = self.args[0].expand(deep, **hints).as_real_imag()
else:
x, y = self.args[0].as_real_imag()
re = (self.func(x + I*y) + self.func(x - I*y))/2
im = (self.func(x + I*y) - self.func(x - I*y))/(2*I)
return (re, im)
###############################################################################
################################ ERROR FUNCTION ###############################
###############################################################################
class erf(Function):
r"""
The Gauss error function.
Explanation
===========
This function is defined as:
.. math ::
\mathrm{erf}(x) = \frac{2}{\sqrt{\pi}} \int_0^x e^{-t^2} \mathrm{d}t.
Examples
========
>>> from sympy import I, oo, erf
>>> from sympy.abc import z
Several special values are known:
>>> erf(0)
0
>>> erf(oo)
1
>>> erf(-oo)
-1
>>> erf(I*oo)
oo*I
>>> erf(-I*oo)
-oo*I
In general one can pull out factors of -1 and $I$ from the argument:
>>> erf(-z)
-erf(z)
The error function obeys the mirror symmetry:
>>> from sympy import conjugate
>>> conjugate(erf(z))
erf(conjugate(z))
Differentiation with respect to $z$ is supported:
>>> from sympy import diff
>>> diff(erf(z), z)
2*exp(-z**2)/sqrt(pi)
We can numerically evaluate the error function to arbitrary precision
on the whole complex plane:
>>> erf(4).evalf(30)
0.999999984582742099719981147840
>>> erf(-4*I).evalf(30)
-1296959.73071763923152794095062*I
See Also
========
erfc: Complementary error function.
erfi: Imaginary error function.
erf2: Two-argument error function.
erfinv: Inverse error function.
erfcinv: Inverse Complementary error function.
erf2inv: Inverse two-argument error function.
References
==========
.. [1] https://en.wikipedia.org/wiki/Error_function
.. [2] https://dlmf.nist.gov/7
.. [3] https://mathworld.wolfram.com/Erf.html
.. [4] https://functions.wolfram.com/GammaBetaErf/Erf
"""
unbranched = True
def fdiff(self, argindex=1):
if argindex == 1:
return 2*exp(-self.args[0]**2)/sqrt(pi)
else:
raise ArgumentIndexError(self, argindex)
def inverse(self, argindex=1):
"""
Returns the inverse of this function.
"""
return erfinv
@classmethod
def eval(cls, arg):
if arg.is_Number:
if arg is S.NaN:
return S.NaN
elif arg is S.Infinity:
return S.One
elif arg is S.NegativeInfinity:
return S.NegativeOne
elif arg.is_zero:
return S.Zero
if isinstance(arg, erfinv):
return arg.args[0]
if isinstance(arg, erfcinv):
return S.One - arg.args[0]
if arg.is_zero:
return S.Zero
# Only happens with unevaluated erf2inv
if isinstance(arg, erf2inv) and arg.args[0].is_zero:
return arg.args[1]
# Try to pull out factors of I
t = arg.extract_multiplicatively(I)
if t in (S.Infinity, S.NegativeInfinity):
return arg
# Try to pull out factors of -1
if arg.could_extract_minus_sign():
return -cls(-arg)
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
if n < 0 or n % 2 == 0:
return S.Zero
else:
x = sympify(x)
k = floor((n - 1)/S(2))
if len(previous_terms) > 2:
return -previous_terms[-2] * x**2 * (n - 2)/(n*k)
else:
return 2*S.NegativeOne**k * x**n/(n*factorial(k)*sqrt(pi))
def _eval_conjugate(self):
return self.func(self.args[0].conjugate())
def _eval_is_real(self):
return self.args[0].is_extended_real
def _eval_is_finite(self):
if self.args[0].is_finite:
return True
else:
return self.args[0].is_extended_real
def _eval_is_zero(self):
return self.args[0].is_zero
def _eval_rewrite_as_uppergamma(self, z, **kwargs):
from sympy.functions.special.gamma_functions import uppergamma
return sqrt(z**2)/z*(S.One - uppergamma(S.Half, z**2)/sqrt(pi))
def _eval_rewrite_as_fresnels(self, z, **kwargs):
arg = (S.One - I)*z/sqrt(pi)
return (S.One + I)*(fresnelc(arg) - I*fresnels(arg))
def _eval_rewrite_as_fresnelc(self, z, **kwargs):
arg = (S.One - I)*z/sqrt(pi)
return (S.One + I)*(fresnelc(arg) - I*fresnels(arg))
def _eval_rewrite_as_meijerg(self, z, **kwargs):
return z/sqrt(pi)*meijerg([S.Half], [], [0], [Rational(-1, 2)], z**2)
def _eval_rewrite_as_hyper(self, z, **kwargs):
return 2*z/sqrt(pi)*hyper([S.Half], [3*S.Half], -z**2)
def _eval_rewrite_as_expint(self, z, **kwargs):
return sqrt(z**2)/z - z*expint(S.Half, z**2)/sqrt(pi)
def _eval_rewrite_as_tractable(self, z, limitvar=None, **kwargs):
from sympy.series.limits import limit
if limitvar:
lim = limit(z, limitvar, S.Infinity)
if lim is S.NegativeInfinity:
return S.NegativeOne + _erfs(-z)*exp(-z**2)
return S.One - _erfs(z)*exp(-z**2)
def _eval_rewrite_as_erfc(self, z, **kwargs):
return S.One - erfc(z)
def _eval_rewrite_as_erfi(self, z, **kwargs):
return -I*erfi(I*z)
def _eval_as_leading_term(self, x, logx=None, cdir=0):
arg = self.args[0].as_leading_term(x, logx=logx, cdir=cdir)
arg0 = arg.subs(x, 0)
if arg0 is S.ComplexInfinity:
arg0 = arg.limit(x, 0, dir='-' if cdir == -1 else '+')
if x in arg.free_symbols and arg0.is_zero:
return 2*arg/sqrt(pi)
else:
return self.func(arg0)
def _eval_aseries(self, n, args0, x, logx):
from sympy.series.order import Order
point = args0[0]
if point in [S.Infinity, S.NegativeInfinity]:
z = self.args[0]
try:
_, ex = z.leadterm(x)
except (ValueError, NotImplementedError):
return self
ex = -ex # as x->1/x for aseries
if ex.is_positive:
newn = ceiling(n/ex)
s = [S.NegativeOne**k * factorial2(2*k - 1) / (z**(2*k + 1) * 2**k)
for k in range(newn)] + [Order(1/z**newn, x)]
return S.One - (exp(-z**2)/sqrt(pi)) * Add(*s)
return super(erf, self)._eval_aseries(n, args0, x, logx)
as_real_imag = real_to_real_as_real_imag
class erfc(Function):
r"""
Complementary Error Function.
Explanation
===========
The function is defined as:
.. math ::
\mathrm{erfc}(x) = \frac{2}{\sqrt{\pi}} \int_x^\infty e^{-t^2} \mathrm{d}t
Examples
========
>>> from sympy import I, oo, erfc
>>> from sympy.abc import z
Several special values are known:
>>> erfc(0)
1
>>> erfc(oo)
0
>>> erfc(-oo)
2
>>> erfc(I*oo)
-oo*I
>>> erfc(-I*oo)
oo*I
The error function obeys the mirror symmetry:
>>> from sympy import conjugate
>>> conjugate(erfc(z))
erfc(conjugate(z))
Differentiation with respect to $z$ is supported:
>>> from sympy import diff
>>> diff(erfc(z), z)
-2*exp(-z**2)/sqrt(pi)
It also follows
>>> erfc(-z)
2 - erfc(z)
We can numerically evaluate the complementary error function to arbitrary
precision on the whole complex plane:
>>> erfc(4).evalf(30)
0.0000000154172579002800188521596734869
>>> erfc(4*I).evalf(30)
1.0 - 1296959.73071763923152794095062*I
See Also
========
erf: Gaussian error function.
erfi: Imaginary error function.
erf2: Two-argument error function.
erfinv: Inverse error function.
erfcinv: Inverse Complementary error function.
erf2inv: Inverse two-argument error function.
References
==========
.. [1] https://en.wikipedia.org/wiki/Error_function
.. [2] https://dlmf.nist.gov/7
.. [3] https://mathworld.wolfram.com/Erfc.html
.. [4] https://functions.wolfram.com/GammaBetaErf/Erfc
"""
unbranched = True
def fdiff(self, argindex=1):
if argindex == 1:
return -2*exp(-self.args[0]**2)/sqrt(pi)
else:
raise ArgumentIndexError(self, argindex)
def inverse(self, argindex=1):
"""
Returns the inverse of this function.
"""
return erfcinv
@classmethod
def eval(cls, arg):
if arg.is_Number:
if arg is S.NaN:
return S.NaN
elif arg is S.Infinity:
return S.Zero
elif arg.is_zero:
return S.One
if isinstance(arg, erfinv):
return S.One - arg.args[0]
if isinstance(arg, erfcinv):
return arg.args[0]
if arg.is_zero:
return S.One
# Try to pull out factors of I
t = arg.extract_multiplicatively(I)
if t in (S.Infinity, S.NegativeInfinity):
return -arg
# Try to pull out factors of -1
if arg.could_extract_minus_sign():
return 2 - cls(-arg)
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
if n == 0:
return S.One
elif n < 0 or n % 2 == 0:
return S.Zero
else:
x = sympify(x)
k = floor((n - 1)/S(2))
if len(previous_terms) > 2:
return -previous_terms[-2] * x**2 * (n - 2)/(n*k)
else:
return -2*S.NegativeOne**k * x**n/(n*factorial(k)*sqrt(pi))
def _eval_conjugate(self):
return self.func(self.args[0].conjugate())
def _eval_is_real(self):
return self.args[0].is_extended_real
def _eval_rewrite_as_tractable(self, z, limitvar=None, **kwargs):
return self.rewrite(erf).rewrite("tractable", deep=True, limitvar=limitvar)
def _eval_rewrite_as_erf(self, z, **kwargs):
return S.One - erf(z)
def _eval_rewrite_as_erfi(self, z, **kwargs):
return S.One + I*erfi(I*z)
def _eval_rewrite_as_fresnels(self, z, **kwargs):
arg = (S.One - I)*z/sqrt(pi)
return S.One - (S.One + I)*(fresnelc(arg) - I*fresnels(arg))
def _eval_rewrite_as_fresnelc(self, z, **kwargs):
arg = (S.One-I)*z/sqrt(pi)
return S.One - (S.One + I)*(fresnelc(arg) - I*fresnels(arg))
def _eval_rewrite_as_meijerg(self, z, **kwargs):
return S.One - z/sqrt(pi)*meijerg([S.Half], [], [0], [Rational(-1, 2)], z**2)
def _eval_rewrite_as_hyper(self, z, **kwargs):
return S.One - 2*z/sqrt(pi)*hyper([S.Half], [3*S.Half], -z**2)
def _eval_rewrite_as_uppergamma(self, z, **kwargs):
from sympy.functions.special.gamma_functions import uppergamma
return S.One - sqrt(z**2)/z*(S.One - uppergamma(S.Half, z**2)/sqrt(pi))
def _eval_rewrite_as_expint(self, z, **kwargs):
return S.One - sqrt(z**2)/z + z*expint(S.Half, z**2)/sqrt(pi)
def _eval_expand_func(self, **hints):
return self.rewrite(erf)
def _eval_as_leading_term(self, x, logx=None, cdir=0):
arg = self.args[0].as_leading_term(x, logx=logx, cdir=cdir)
arg0 = arg.subs(x, 0)
if arg0 is S.ComplexInfinity:
arg0 = arg.limit(x, 0, dir='-' if cdir == -1 else '+')
if arg0.is_zero:
return S.One
else:
return self.func(arg0)
as_real_imag = real_to_real_as_real_imag
def _eval_aseries(self, n, args0, x, logx):
return S.One - erf(*self.args)._eval_aseries(n, args0, x, logx)
class erfi(Function):
r"""
Imaginary error function.
Explanation
===========
The function erfi is defined as:
.. math ::
\mathrm{erfi}(x) = \frac{2}{\sqrt{\pi}} \int_0^x e^{t^2} \mathrm{d}t
Examples
========
>>> from sympy import I, oo, erfi
>>> from sympy.abc import z
Several special values are known:
>>> erfi(0)
0
>>> erfi(oo)
oo
>>> erfi(-oo)
-oo
>>> erfi(I*oo)
I
>>> erfi(-I*oo)
-I
In general one can pull out factors of -1 and $I$ from the argument:
>>> erfi(-z)
-erfi(z)
>>> from sympy import conjugate
>>> conjugate(erfi(z))
erfi(conjugate(z))
Differentiation with respect to $z$ is supported:
>>> from sympy import diff
>>> diff(erfi(z), z)
2*exp(z**2)/sqrt(pi)
We can numerically evaluate the imaginary error function to arbitrary
precision on the whole complex plane:
>>> erfi(2).evalf(30)
18.5648024145755525987042919132
>>> erfi(-2*I).evalf(30)
-0.995322265018952734162069256367*I
See Also
========
erf: Gaussian error function.
erfc: Complementary error function.
erf2: Two-argument error function.
erfinv: Inverse error function.
erfcinv: Inverse Complementary error function.
erf2inv: Inverse two-argument error function.
References
==========
.. [1] https://en.wikipedia.org/wiki/Error_function
.. [2] https://mathworld.wolfram.com/Erfi.html
.. [3] https://functions.wolfram.com/GammaBetaErf/Erfi
"""
unbranched = True
def fdiff(self, argindex=1):
if argindex == 1:
return 2*exp(self.args[0]**2)/sqrt(pi)
else:
raise ArgumentIndexError(self, argindex)
@classmethod
def eval(cls, z):
if z.is_Number:
if z is S.NaN:
return S.NaN
elif z.is_zero:
return S.Zero
elif z is S.Infinity:
return S.Infinity
if z.is_zero:
return S.Zero
# Try to pull out factors of -1
if z.could_extract_minus_sign():
return -cls(-z)
# Try to pull out factors of I
nz = z.extract_multiplicatively(I)
if nz is not None:
if nz is S.Infinity:
return I
if isinstance(nz, erfinv):
return I*nz.args[0]
if isinstance(nz, erfcinv):
return I*(S.One - nz.args[0])
# Only happens with unevaluated erf2inv
if isinstance(nz, erf2inv) and nz.args[0].is_zero:
return I*nz.args[1]
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
if n < 0 or n % 2 == 0:
return S.Zero
else:
x = sympify(x)
k = floor((n - 1)/S(2))
if len(previous_terms) > 2:
return previous_terms[-2] * x**2 * (n - 2)/(n*k)
else:
return 2 * x**n/(n*factorial(k)*sqrt(pi))
def _eval_conjugate(self):
return self.func(self.args[0].conjugate())
def _eval_is_extended_real(self):
return self.args[0].is_extended_real
def _eval_is_zero(self):
return self.args[0].is_zero
def _eval_rewrite_as_tractable(self, z, limitvar=None, **kwargs):
return self.rewrite(erf).rewrite("tractable", deep=True, limitvar=limitvar)
def _eval_rewrite_as_erf(self, z, **kwargs):
return -I*erf(I*z)
def _eval_rewrite_as_erfc(self, z, **kwargs):
return I*erfc(I*z) - I
def _eval_rewrite_as_fresnels(self, z, **kwargs):
arg = (S.One + I)*z/sqrt(pi)
return (S.One - I)*(fresnelc(arg) - I*fresnels(arg))
def _eval_rewrite_as_fresnelc(self, z, **kwargs):
arg = (S.One + I)*z/sqrt(pi)
return (S.One - I)*(fresnelc(arg) - I*fresnels(arg))
def _eval_rewrite_as_meijerg(self, z, **kwargs):
return z/sqrt(pi)*meijerg([S.Half], [], [0], [Rational(-1, 2)], -z**2)
def _eval_rewrite_as_hyper(self, z, **kwargs):
return 2*z/sqrt(pi)*hyper([S.Half], [3*S.Half], z**2)
def _eval_rewrite_as_uppergamma(self, z, **kwargs):
from sympy.functions.special.gamma_functions import uppergamma
return sqrt(-z**2)/z*(uppergamma(S.Half, -z**2)/sqrt(pi) - S.One)
def _eval_rewrite_as_expint(self, z, **kwargs):
return sqrt(-z**2)/z - z*expint(S.Half, -z**2)/sqrt(pi)
def _eval_expand_func(self, **hints):
return self.rewrite(erf)
as_real_imag = real_to_real_as_real_imag
def _eval_as_leading_term(self, x, logx=None, cdir=0):
arg = self.args[0].as_leading_term(x, logx=logx, cdir=cdir)
arg0 = arg.subs(x, 0)
if x in arg.free_symbols and arg0.is_zero:
return 2*arg/sqrt(pi)
elif arg0.is_finite:
return self.func(arg0)
return self.func(arg)
def _eval_aseries(self, n, args0, x, logx):
from sympy.series.order import Order
point = args0[0]
if point is S.Infinity:
z = self.args[0]
s = [factorial2(2*k - 1) / (2**k * z**(2*k + 1))
for k in range(n)] + [Order(1/z**n, x)]
return -I + (exp(z**2)/sqrt(pi)) * Add(*s)
return super(erfi, self)._eval_aseries(n, args0, x, logx)
class erf2(Function):
r"""
Two-argument error function.
Explanation
===========
This function is defined as:
.. math ::
\mathrm{erf2}(x, y) = \frac{2}{\sqrt{\pi}} \int_x^y e^{-t^2} \mathrm{d}t
Examples
========
>>> from sympy import oo, erf2
>>> from sympy.abc import x, y
Several special values are known:
>>> erf2(0, 0)
0
>>> erf2(x, x)
0
>>> erf2(x, oo)
1 - erf(x)
>>> erf2(x, -oo)
-erf(x) - 1
>>> erf2(oo, y)
erf(y) - 1
>>> erf2(-oo, y)
erf(y) + 1
In general one can pull out factors of -1:
>>> erf2(-x, -y)
-erf2(x, y)
The error function obeys the mirror symmetry:
>>> from sympy import conjugate
>>> conjugate(erf2(x, y))
erf2(conjugate(x), conjugate(y))
Differentiation with respect to $x$, $y$ is supported:
>>> from sympy import diff
>>> diff(erf2(x, y), x)
-2*exp(-x**2)/sqrt(pi)
>>> diff(erf2(x, y), y)
2*exp(-y**2)/sqrt(pi)
See Also
========
erf: Gaussian error function.
erfc: Complementary error function.
erfi: Imaginary error function.
erfinv: Inverse error function.
erfcinv: Inverse Complementary error function.
erf2inv: Inverse two-argument error function.
References
==========
.. [1] https://functions.wolfram.com/GammaBetaErf/Erf2/
"""
def fdiff(self, argindex):
x, y = self.args
if argindex == 1:
return -2*exp(-x**2)/sqrt(pi)
elif argindex == 2:
return 2*exp(-y**2)/sqrt(pi)
else:
raise ArgumentIndexError(self, argindex)
@classmethod
def eval(cls, x, y):
chk = (S.Infinity, S.NegativeInfinity, S.Zero)
if x is S.NaN or y is S.NaN:
return S.NaN
elif x == y:
return S.Zero
elif x in chk or y in chk:
return erf(y) - erf(x)
if isinstance(y, erf2inv) and y.args[0] == x:
return y.args[1]
if x.is_zero or y.is_zero or x.is_extended_real and x.is_infinite or \
y.is_extended_real and y.is_infinite:
return erf(y) - erf(x)
#Try to pull out -1 factor
sign_x = x.could_extract_minus_sign()
sign_y = y.could_extract_minus_sign()
if (sign_x and sign_y):
return -cls(-x, -y)
elif (sign_x or sign_y):
return erf(y)-erf(x)
def _eval_conjugate(self):
return self.func(self.args[0].conjugate(), self.args[1].conjugate())
def _eval_is_extended_real(self):
return self.args[0].is_extended_real and self.args[1].is_extended_real
def _eval_rewrite_as_erf(self, x, y, **kwargs):
return erf(y) - erf(x)
def _eval_rewrite_as_erfc(self, x, y, **kwargs):
return erfc(x) - erfc(y)
def _eval_rewrite_as_erfi(self, x, y, **kwargs):
return I*(erfi(I*x)-erfi(I*y))
def _eval_rewrite_as_fresnels(self, x, y, **kwargs):
return erf(y).rewrite(fresnels) - erf(x).rewrite(fresnels)
def _eval_rewrite_as_fresnelc(self, x, y, **kwargs):
return erf(y).rewrite(fresnelc) - erf(x).rewrite(fresnelc)
def _eval_rewrite_as_meijerg(self, x, y, **kwargs):
return erf(y).rewrite(meijerg) - erf(x).rewrite(meijerg)
def _eval_rewrite_as_hyper(self, x, y, **kwargs):
return erf(y).rewrite(hyper) - erf(x).rewrite(hyper)
def _eval_rewrite_as_uppergamma(self, x, y, **kwargs):
from sympy.functions.special.gamma_functions import uppergamma
return (sqrt(y**2)/y*(S.One - uppergamma(S.Half, y**2)/sqrt(pi)) -
sqrt(x**2)/x*(S.One - uppergamma(S.Half, x**2)/sqrt(pi)))
def _eval_rewrite_as_expint(self, x, y, **kwargs):
return erf(y).rewrite(expint) - erf(x).rewrite(expint)
def _eval_expand_func(self, **hints):
return self.rewrite(erf)
def _eval_is_zero(self):
return is_eq(*self.args)
class erfinv(Function):
r"""
Inverse Error Function. The erfinv function is defined as:
.. math ::
\mathrm{erf}(x) = y \quad \Rightarrow \quad \mathrm{erfinv}(y) = x
Examples
========
>>> from sympy import erfinv
>>> from sympy.abc import x
Several special values are known:
>>> erfinv(0)
0
>>> erfinv(1)
oo
Differentiation with respect to $x$ is supported:
>>> from sympy import diff
>>> diff(erfinv(x), x)
sqrt(pi)*exp(erfinv(x)**2)/2
We can numerically evaluate the inverse error function to arbitrary
precision on [-1, 1]:
>>> erfinv(0.2).evalf(30)
0.179143454621291692285822705344
See Also
========
erf: Gaussian error function.
erfc: Complementary error function.
erfi: Imaginary error function.
erf2: Two-argument error function.
erfcinv: Inverse Complementary error function.
erf2inv: Inverse two-argument error function.
References
==========
.. [1] https://en.wikipedia.org/wiki/Error_function#Inverse_functions
.. [2] https://functions.wolfram.com/GammaBetaErf/InverseErf/
"""
def fdiff(self, argindex =1):
if argindex == 1:
return sqrt(pi)*exp(self.func(self.args[0])**2)*S.Half
else :
raise ArgumentIndexError(self, argindex)
def inverse(self, argindex=1):
"""
Returns the inverse of this function.
"""
return erf
@classmethod
def eval(cls, z):
if z is S.NaN:
return S.NaN
elif z is S.NegativeOne:
return S.NegativeInfinity
elif z.is_zero:
return S.Zero
elif z is S.One:
return S.Infinity
if isinstance(z, erf) and z.args[0].is_extended_real:
return z.args[0]
if z.is_zero:
return S.Zero
# Try to pull out factors of -1
nz = z.extract_multiplicatively(-1)
if nz is not None and (isinstance(nz, erf) and (nz.args[0]).is_extended_real):
return -nz.args[0]
def _eval_rewrite_as_erfcinv(self, z, **kwargs):
return erfcinv(1-z)
def _eval_is_zero(self):
return self.args[0].is_zero
class erfcinv (Function):
r"""
Inverse Complementary Error Function. The erfcinv function is defined as:
.. math ::
\mathrm{erfc}(x) = y \quad \Rightarrow \quad \mathrm{erfcinv}(y) = x
Examples
========
>>> from sympy import erfcinv
>>> from sympy.abc import x
Several special values are known:
>>> erfcinv(1)
0
>>> erfcinv(0)
oo
Differentiation with respect to $x$ is supported:
>>> from sympy import diff
>>> diff(erfcinv(x), x)
-sqrt(pi)*exp(erfcinv(x)**2)/2
See Also
========
erf: Gaussian error function.
erfc: Complementary error function.
erfi: Imaginary error function.
erf2: Two-argument error function.
erfinv: Inverse error function.
erf2inv: Inverse two-argument error function.
References
==========
.. [1] https://en.wikipedia.org/wiki/Error_function#Inverse_functions
.. [2] https://functions.wolfram.com/GammaBetaErf/InverseErfc/
"""
def fdiff(self, argindex =1):
if argindex == 1:
return -sqrt(pi)*exp(self.func(self.args[0])**2)*S.Half
else:
raise ArgumentIndexError(self, argindex)
def inverse(self, argindex=1):
"""
Returns the inverse of this function.
"""
return erfc
@classmethod
def eval(cls, z):
if z is S.NaN:
return S.NaN
elif z.is_zero:
return S.Infinity
elif z is S.One:
return S.Zero
elif z == 2:
return S.NegativeInfinity
if z.is_zero:
return S.Infinity
def _eval_rewrite_as_erfinv(self, z, **kwargs):
return erfinv(1-z)
def _eval_is_zero(self):
return (self.args[0] - 1).is_zero
def _eval_is_infinite(self):
return self.args[0].is_zero
class erf2inv(Function):
r"""
Two-argument Inverse error function. The erf2inv function is defined as:
.. math ::
\mathrm{erf2}(x, w) = y \quad \Rightarrow \quad \mathrm{erf2inv}(x, y) = w
Examples
========
>>> from sympy import erf2inv, oo
>>> from sympy.abc import x, y
Several special values are known:
>>> erf2inv(0, 0)
0
>>> erf2inv(1, 0)
1
>>> erf2inv(0, 1)
oo
>>> erf2inv(0, y)
erfinv(y)
>>> erf2inv(oo, y)
erfcinv(-y)
Differentiation with respect to $x$ and $y$ is supported:
>>> from sympy import diff
>>> diff(erf2inv(x, y), x)
exp(-x**2 + erf2inv(x, y)**2)
>>> diff(erf2inv(x, y), y)
sqrt(pi)*exp(erf2inv(x, y)**2)/2
See Also
========
erf: Gaussian error function.
erfc: Complementary error function.
erfi: Imaginary error function.
erf2: Two-argument error function.
erfinv: Inverse error function.
erfcinv: Inverse complementary error function.
References
==========
.. [1] https://functions.wolfram.com/GammaBetaErf/InverseErf2/
"""
def fdiff(self, argindex):
x, y = self.args
if argindex == 1:
return exp(self.func(x,y)**2-x**2)
elif argindex == 2:
return sqrt(pi)*S.Half*exp(self.func(x,y)**2)
else:
raise ArgumentIndexError(self, argindex)
@classmethod
def eval(cls, x, y):
if x is S.NaN or y is S.NaN:
return S.NaN
elif x.is_zero and y.is_zero:
return S.Zero
elif x.is_zero and y is S.One:
return S.Infinity
elif x is S.One and y.is_zero:
return S.One
elif x.is_zero:
return erfinv(y)
elif x is S.Infinity:
return erfcinv(-y)
elif y.is_zero:
return x
elif y is S.Infinity:
return erfinv(x)
if x.is_zero:
if y.is_zero:
return S.Zero
else:
return erfinv(y)
if y.is_zero:
return x
def _eval_is_zero(self):
x, y = self.args
if x.is_zero and y.is_zero:
return True
###############################################################################
#################### EXPONENTIAL INTEGRALS ####################################
###############################################################################
class Ei(Function):
r"""
The classical exponential integral.
Explanation
===========
For use in SymPy, this function is defined as
.. math:: \operatorname{Ei}(x) = \sum_{n=1}^\infty \frac{x^n}{n\, n!}
+ \log(x) + \gamma,
where $\gamma$ is the Euler-Mascheroni constant.
If $x$ is a polar number, this defines an analytic function on the
Riemann surface of the logarithm. Otherwise this defines an analytic
function in the cut plane $\mathbb{C} \setminus (-\infty, 0]$.
**Background**
The name exponential integral comes from the following statement:
.. math:: \operatorname{Ei}(x) = \int_{-\infty}^x \frac{e^t}{t} \mathrm{d}t
If the integral is interpreted as a Cauchy principal value, this statement
holds for $x > 0$ and $\operatorname{Ei}(x)$ as defined above.
Examples
========
>>> from sympy import Ei, polar_lift, exp_polar, I, pi
>>> from sympy.abc import x
>>> Ei(-1)
Ei(-1)
This yields a real value:
>>> Ei(-1).n(chop=True)
-0.219383934395520
On the other hand the analytic continuation is not real:
>>> Ei(polar_lift(-1)).n(chop=True)
-0.21938393439552 + 3.14159265358979*I
The exponential integral has a logarithmic branch point at the origin:
>>> Ei(x*exp_polar(2*I*pi))
Ei(x) + 2*I*pi
Differentiation is supported:
>>> Ei(x).diff(x)
exp(x)/x
The exponential integral is related to many other special functions.
For example:
>>> from sympy import expint, Shi
>>> Ei(x).rewrite(expint)
-expint(1, x*exp_polar(I*pi)) - I*pi
>>> Ei(x).rewrite(Shi)
Chi(x) + Shi(x)
See Also
========
expint: Generalised exponential integral.
E1: Special case of the generalised exponential integral.
li: Logarithmic integral.
Li: Offset logarithmic integral.
Si: Sine integral.
Ci: Cosine integral.
Shi: Hyperbolic sine integral.
Chi: Hyperbolic cosine integral.
uppergamma: Upper incomplete gamma function.
References
==========
.. [1] https://dlmf.nist.gov/6.6
.. [2] https://en.wikipedia.org/wiki/Exponential_integral
.. [3] Abramowitz & Stegun, section 5: https://web.archive.org/web/20201128173312/http://people.math.sfu.ca/~cbm/aands/page_228.htm
"""
@classmethod
def eval(cls, z):
if z.is_zero:
return S.NegativeInfinity
elif z is S.Infinity:
return S.Infinity
elif z is S.NegativeInfinity:
return S.Zero
if z.is_zero:
return S.NegativeInfinity
nz, n = z.extract_branch_factor()
if n:
return Ei(nz) + 2*I*pi*n
def fdiff(self, argindex=1):
arg = unpolarify(self.args[0])
if argindex == 1:
return exp(arg)/arg
else:
raise ArgumentIndexError(self, argindex)
def _eval_evalf(self, prec):
if (self.args[0]/polar_lift(-1)).is_positive:
return Function._eval_evalf(self, prec) + (I*pi)._eval_evalf(prec)
return Function._eval_evalf(self, prec)
def _eval_rewrite_as_uppergamma(self, z, **kwargs):
from sympy.functions.special.gamma_functions import uppergamma
# XXX this does not currently work usefully because uppergamma
# immediately turns into expint
return -uppergamma(0, polar_lift(-1)*z) - I*pi
def _eval_rewrite_as_expint(self, z, **kwargs):
return -expint(1, polar_lift(-1)*z) - I*pi
def _eval_rewrite_as_li(self, z, **kwargs):
if isinstance(z, log):
return li(z.args[0])
# TODO:
# Actually it only holds that:
# Ei(z) = li(exp(z))
# for -pi < imag(z) <= pi
return li(exp(z))
def _eval_rewrite_as_Si(self, z, **kwargs):
if z.is_negative:
return Shi(z) + Chi(z) - I*pi
else:
return Shi(z) + Chi(z)
_eval_rewrite_as_Ci = _eval_rewrite_as_Si
_eval_rewrite_as_Chi = _eval_rewrite_as_Si
_eval_rewrite_as_Shi = _eval_rewrite_as_Si
def _eval_rewrite_as_tractable(self, z, limitvar=None, **kwargs):
return exp(z) * _eis(z)
def _eval_rewrite_as_Integral(self, z, **kwargs):
from sympy.integrals.integrals import Integral
t = Dummy(uniquely_named_symbol('t', [z]).name)
return Integral(S.Exp1**t/t, (t, S.NegativeInfinity, z))
def _eval_as_leading_term(self, x, logx=None, cdir=0):
from sympy import re
x0 = self.args[0].limit(x, 0)
arg = self.args[0].as_leading_term(x, cdir=cdir)
cdir = arg.dir(x, cdir)
if x0.is_zero:
c, e = arg.as_coeff_exponent(x)
logx = log(x) if logx is None else logx
return log(c) + e*logx + EulerGamma - (
I*pi if re(cdir).is_negative else S.Zero)
return super()._eval_as_leading_term(x, logx=logx, cdir=cdir)
def _eval_nseries(self, x, n, logx, cdir=0):
x0 = self.args[0].limit(x, 0)
if x0.is_zero:
f = self._eval_rewrite_as_Si(*self.args)
return f._eval_nseries(x, n, logx)
return super()._eval_nseries(x, n, logx)
def _eval_aseries(self, n, args0, x, logx):
from sympy.series.order import Order
point = args0[0]
if point is S.Infinity:
z = self.args[0]
s = [factorial(k) / (z)**k for k in range(n)] + \
[Order(1/z**n, x)]
return (exp(z)/z) * Add(*s)
return super(Ei, self)._eval_aseries(n, args0, x, logx)
class expint(Function):
r"""
Generalized exponential integral.
Explanation
===========
This function is defined as
.. math:: \operatorname{E}_\nu(z) = z^{\nu - 1} \Gamma(1 - \nu, z),
where $\Gamma(1 - \nu, z)$ is the upper incomplete gamma function
(``uppergamma``).
Hence for $z$ with positive real part we have
.. math:: \operatorname{E}_\nu(z)
= \int_1^\infty \frac{e^{-zt}}{t^\nu} \mathrm{d}t,
which explains the name.
The representation as an incomplete gamma function provides an analytic
continuation for $\operatorname{E}_\nu(z)$. If $\nu$ is a
non-positive integer, the exponential integral is thus an unbranched
function of $z$, otherwise there is a branch point at the origin.
Refer to the incomplete gamma function documentation for details of the
branching behavior.
Examples
========
>>> from sympy import expint, S
>>> from sympy.abc import nu, z
Differentiation is supported. Differentiation with respect to $z$ further
explains the name: for integral orders, the exponential integral is an
iterated integral of the exponential function.
>>> expint(nu, z).diff(z)
-expint(nu - 1, z)
Differentiation with respect to $\nu$ has no classical expression:
>>> expint(nu, z).diff(nu)
-z**(nu - 1)*meijerg(((), (1, 1)), ((0, 0, 1 - nu), ()), z)
At non-postive integer orders, the exponential integral reduces to the
exponential function:
>>> expint(0, z)
exp(-z)/z
>>> expint(-1, z)
exp(-z)/z + exp(-z)/z**2
At half-integers it reduces to error functions:
>>> expint(S(1)/2, z)
sqrt(pi)*erfc(sqrt(z))/sqrt(z)
At positive integer orders it can be rewritten in terms of exponentials
and ``expint(1, z)``. Use ``expand_func()`` to do this:
>>> from sympy import expand_func
>>> expand_func(expint(5, z))
z**4*expint(1, z)/24 + (-z**3 + z**2 - 2*z + 6)*exp(-z)/24
The generalised exponential integral is essentially equivalent to the
incomplete gamma function:
>>> from sympy import uppergamma
>>> expint(nu, z).rewrite(uppergamma)
z**(nu - 1)*uppergamma(1 - nu, z)
As such it is branched at the origin:
>>> from sympy import exp_polar, pi, I
>>> expint(4, z*exp_polar(2*pi*I))
I*pi*z**3/3 + expint(4, z)
>>> expint(nu, z*exp_polar(2*pi*I))
z**(nu - 1)*(exp(2*I*pi*nu) - 1)*gamma(1 - nu) + expint(nu, z)
See Also
========
Ei: Another related function called exponential integral.
E1: The classical case, returns expint(1, z).
li: Logarithmic integral.
Li: Offset logarithmic integral.
Si: Sine integral.
Ci: Cosine integral.
Shi: Hyperbolic sine integral.
Chi: Hyperbolic cosine integral.
uppergamma
References
==========
.. [1] https://dlmf.nist.gov/8.19
.. [2] https://functions.wolfram.com/GammaBetaErf/ExpIntegralE/
.. [3] https://en.wikipedia.org/wiki/Exponential_integral
"""
@classmethod
def eval(cls, nu, z):
from sympy.functions.special.gamma_functions import (gamma, uppergamma)
nu2 = unpolarify(nu)
if nu != nu2:
return expint(nu2, z)
if nu.is_Integer and nu <= 0 or (not nu.is_Integer and (2*nu).is_Integer):
return unpolarify(expand_mul(z**(nu - 1)*uppergamma(1 - nu, z)))
# Extract branching information. This can be deduced from what is
# explained in lowergamma.eval().
z, n = z.extract_branch_factor()
if n is S.Zero:
return
if nu.is_integer:
if not nu > 0:
return
return expint(nu, z) \
- 2*pi*I*n*S.NegativeOne**(nu - 1)/factorial(nu - 1)*unpolarify(z)**(nu - 1)
else:
return (exp(2*I*pi*nu*n) - 1)*z**(nu - 1)*gamma(1 - nu) + expint(nu, z)
def fdiff(self, argindex):
nu, z = self.args
if argindex == 1:
return -z**(nu - 1)*meijerg([], [1, 1], [0, 0, 1 - nu], [], z)
elif argindex == 2:
return -expint(nu - 1, z)
else:
raise ArgumentIndexError(self, argindex)
def _eval_rewrite_as_uppergamma(self, nu, z, **kwargs):
from sympy.functions.special.gamma_functions import uppergamma
return z**(nu - 1)*uppergamma(1 - nu, z)
def _eval_rewrite_as_Ei(self, nu, z, **kwargs):
if nu == 1:
return -Ei(z*exp_polar(-I*pi)) - I*pi
elif nu.is_Integer and nu > 1:
# DLMF, 8.19.7
x = -unpolarify(z)
return x**(nu - 1)/factorial(nu - 1)*E1(z).rewrite(Ei) + \
exp(x)/factorial(nu - 1) * \
Add(*[factorial(nu - k - 2)*x**k for k in range(nu - 1)])
else:
return self
def _eval_expand_func(self, **hints):
return self.rewrite(Ei).rewrite(expint, **hints)
def _eval_rewrite_as_Si(self, nu, z, **kwargs):
if nu != 1:
return self
return Shi(z) - Chi(z)
_eval_rewrite_as_Ci = _eval_rewrite_as_Si
_eval_rewrite_as_Chi = _eval_rewrite_as_Si
_eval_rewrite_as_Shi = _eval_rewrite_as_Si
def _eval_nseries(self, x, n, logx, cdir=0):
if not self.args[0].has(x):
nu = self.args[0]
if nu == 1:
f = self._eval_rewrite_as_Si(*self.args)
return f._eval_nseries(x, n, logx)
elif nu.is_Integer and nu > 1:
f = self._eval_rewrite_as_Ei(*self.args)
return f._eval_nseries(x, n, logx)
return super()._eval_nseries(x, n, logx)
def _eval_aseries(self, n, args0, x, logx):
from sympy.series.order import Order
point = args0[1]
nu = self.args[0]
if point is S.Infinity:
z = self.args[1]
s = [S.NegativeOne**k * RisingFactorial(nu, k) / z**k for k in range(n)] + [Order(1/z**n, x)]
return (exp(-z)/z) * Add(*s)
return super(expint, self)._eval_aseries(n, args0, x, logx)
def _eval_rewrite_as_Integral(self, *args, **kwargs):
from sympy.integrals.integrals import Integral
n, x = self.args
t = Dummy(uniquely_named_symbol('t', args).name)
return Integral(t**-n * exp(-t*x), (t, 1, S.Infinity))
def E1(z):
"""
Classical case of the generalized exponential integral.
Explanation
===========
This is equivalent to ``expint(1, z)``.
Examples
========
>>> from sympy import E1
>>> E1(0)
expint(1, 0)
>>> E1(5)
expint(1, 5)
See Also
========
Ei: Exponential integral.
expint: Generalised exponential integral.
li: Logarithmic integral.
Li: Offset logarithmic integral.
Si: Sine integral.
Ci: Cosine integral.
Shi: Hyperbolic sine integral.
Chi: Hyperbolic cosine integral.
"""
return expint(1, z)
class li(Function):
r"""
The classical logarithmic integral.
Explanation
===========
For use in SymPy, this function is defined as
.. math:: \operatorname{li}(x) = \int_0^x \frac{1}{\log(t)} \mathrm{d}t \,.
Examples
========
>>> from sympy import I, oo, li
>>> from sympy.abc import z
Several special values are known:
>>> li(0)
0
>>> li(1)
-oo
>>> li(oo)
oo
Differentiation with respect to $z$ is supported:
>>> from sympy import diff
>>> diff(li(z), z)
1/log(z)
Defining the ``li`` function via an integral:
>>> from sympy import integrate
>>> integrate(li(z))
z*li(z) - Ei(2*log(z))
>>> integrate(li(z),z)
z*li(z) - Ei(2*log(z))
The logarithmic integral can also be defined in terms of ``Ei``:
>>> from sympy import Ei
>>> li(z).rewrite(Ei)
Ei(log(z))
>>> diff(li(z).rewrite(Ei), z)
1/log(z)
We can numerically evaluate the logarithmic integral to arbitrary precision
on the whole complex plane (except the singular points):
>>> li(2).evalf(30)
1.04516378011749278484458888919
>>> li(2*I).evalf(30)
1.0652795784357498247001125598 + 3.08346052231061726610939702133*I
We can even compute Soldner's constant by the help of mpmath:
>>> from mpmath import findroot
>>> findroot(li, 2)
1.45136923488338
Further transformations include rewriting ``li`` in terms of
the trigonometric integrals ``Si``, ``Ci``, ``Shi`` and ``Chi``:
>>> from sympy import Si, Ci, Shi, Chi
>>> li(z).rewrite(Si)
-log(I*log(z)) - log(1/log(z))/2 + log(log(z))/2 + Ci(I*log(z)) + Shi(log(z))
>>> li(z).rewrite(Ci)
-log(I*log(z)) - log(1/log(z))/2 + log(log(z))/2 + Ci(I*log(z)) + Shi(log(z))
>>> li(z).rewrite(Shi)
-log(1/log(z))/2 + log(log(z))/2 + Chi(log(z)) - Shi(log(z))
>>> li(z).rewrite(Chi)
-log(1/log(z))/2 + log(log(z))/2 + Chi(log(z)) - Shi(log(z))
See Also
========
Li: Offset logarithmic integral.
Ei: Exponential integral.
expint: Generalised exponential integral.
E1: Special case of the generalised exponential integral.
Si: Sine integral.
Ci: Cosine integral.
Shi: Hyperbolic sine integral.
Chi: Hyperbolic cosine integral.
References
==========
.. [1] https://en.wikipedia.org/wiki/Logarithmic_integral
.. [2] https://mathworld.wolfram.com/LogarithmicIntegral.html
.. [3] https://dlmf.nist.gov/6
.. [4] https://mathworld.wolfram.com/SoldnersConstant.html
"""
@classmethod
def eval(cls, z):
if z.is_zero:
return S.Zero
elif z is S.One:
return S.NegativeInfinity
elif z is S.Infinity:
return S.Infinity
if z.is_zero:
return S.Zero
def fdiff(self, argindex=1):
arg = self.args[0]
if argindex == 1:
return S.One / log(arg)
else:
raise ArgumentIndexError(self, argindex)
def _eval_conjugate(self):
z = self.args[0]
# Exclude values on the branch cut (-oo, 0)
if not z.is_extended_negative:
return self.func(z.conjugate())
def _eval_rewrite_as_Li(self, z, **kwargs):
return Li(z) + li(2)
def _eval_rewrite_as_Ei(self, z, **kwargs):
return Ei(log(z))
def _eval_rewrite_as_uppergamma(self, z, **kwargs):
from sympy.functions.special.gamma_functions import uppergamma
return (-uppergamma(0, -log(z)) +
S.Half*(log(log(z)) - log(S.One/log(z))) - log(-log(z)))
def _eval_rewrite_as_Si(self, z, **kwargs):
return (Ci(I*log(z)) - I*Si(I*log(z)) -
S.Half*(log(S.One/log(z)) - log(log(z))) - log(I*log(z)))
_eval_rewrite_as_Ci = _eval_rewrite_as_Si
def _eval_rewrite_as_Shi(self, z, **kwargs):
return (Chi(log(z)) - Shi(log(z)) - S.Half*(log(S.One/log(z)) - log(log(z))))
_eval_rewrite_as_Chi = _eval_rewrite_as_Shi
def _eval_rewrite_as_hyper(self, z, **kwargs):
return (log(z)*hyper((1, 1), (2, 2), log(z)) +
S.Half*(log(log(z)) - log(S.One/log(z))) + EulerGamma)
def _eval_rewrite_as_meijerg(self, z, **kwargs):
return (-log(-log(z)) - S.Half*(log(S.One/log(z)) - log(log(z)))
- meijerg(((), (1,)), ((0, 0), ()), -log(z)))
def _eval_rewrite_as_tractable(self, z, limitvar=None, **kwargs):
return z * _eis(log(z))
def _eval_nseries(self, x, n, logx, cdir=0):
z = self.args[0]
s = [(log(z))**k / (factorial(k) * k) for k in range(1, n)]
return EulerGamma + log(log(z)) + Add(*s)
def _eval_is_zero(self):
z = self.args[0]
if z.is_zero:
return True
class Li(Function):
r"""
The offset logarithmic integral.
Explanation
===========
For use in SymPy, this function is defined as
.. math:: \operatorname{Li}(x) = \operatorname{li}(x) - \operatorname{li}(2)
Examples
========
>>> from sympy import Li
>>> from sympy.abc import z
The following special value is known:
>>> Li(2)
0
Differentiation with respect to $z$ is supported:
>>> from sympy import diff
>>> diff(Li(z), z)
1/log(z)
The shifted logarithmic integral can be written in terms of $li(z)$:
>>> from sympy import li
>>> Li(z).rewrite(li)
li(z) - li(2)
We can numerically evaluate the logarithmic integral to arbitrary precision
on the whole complex plane (except the singular points):
>>> Li(2).evalf(30)
0
>>> Li(4).evalf(30)
1.92242131492155809316615998938
See Also
========
li: Logarithmic integral.
Ei: Exponential integral.
expint: Generalised exponential integral.
E1: Special case of the generalised exponential integral.
Si: Sine integral.
Ci: Cosine integral.
Shi: Hyperbolic sine integral.
Chi: Hyperbolic cosine integral.
References
==========
.. [1] https://en.wikipedia.org/wiki/Logarithmic_integral
.. [2] https://mathworld.wolfram.com/LogarithmicIntegral.html
.. [3] https://dlmf.nist.gov/6
"""
@classmethod
def eval(cls, z):
if z is S.Infinity:
return S.Infinity
elif z == S(2):
return S.Zero
def fdiff(self, argindex=1):
arg = self.args[0]
if argindex == 1:
return S.One / log(arg)
else:
raise ArgumentIndexError(self, argindex)
def _eval_evalf(self, prec):
return self.rewrite(li).evalf(prec)
def _eval_rewrite_as_li(self, z, **kwargs):
return li(z) - li(2)
def _eval_rewrite_as_tractable(self, z, limitvar=None, **kwargs):
return self.rewrite(li).rewrite("tractable", deep=True)
def _eval_nseries(self, x, n, logx, cdir=0):
f = self._eval_rewrite_as_li(*self.args)
return f._eval_nseries(x, n, logx)
###############################################################################
#################### TRIGONOMETRIC INTEGRALS ##################################
###############################################################################
class TrigonometricIntegral(Function):
""" Base class for trigonometric integrals. """
@classmethod
def eval(cls, z):
if z is S.Zero:
return cls._atzero
elif z is S.Infinity:
return cls._atinf()
elif z is S.NegativeInfinity:
return cls._atneginf()
if z.is_zero:
return cls._atzero
nz = z.extract_multiplicatively(polar_lift(I))
if nz is None and cls._trigfunc(0) == 0:
nz = z.extract_multiplicatively(I)
if nz is not None:
return cls._Ifactor(nz, 1)
nz = z.extract_multiplicatively(polar_lift(-I))
if nz is not None:
return cls._Ifactor(nz, -1)
nz = z.extract_multiplicatively(polar_lift(-1))
if nz is None and cls._trigfunc(0) == 0:
nz = z.extract_multiplicatively(-1)
if nz is not None:
return cls._minusfactor(nz)
nz, n = z.extract_branch_factor()
if n == 0 and nz == z:
return
return 2*pi*I*n*cls._trigfunc(0) + cls(nz)
def fdiff(self, argindex=1):
arg = unpolarify(self.args[0])
if argindex == 1:
return self._trigfunc(arg)/arg
else:
raise ArgumentIndexError(self, argindex)
def _eval_rewrite_as_Ei(self, z, **kwargs):
return self._eval_rewrite_as_expint(z).rewrite(Ei)
def _eval_rewrite_as_uppergamma(self, z, **kwargs):
from sympy.functions.special.gamma_functions import uppergamma
return self._eval_rewrite_as_expint(z).rewrite(uppergamma)
def _eval_nseries(self, x, n, logx, cdir=0):
# NOTE this is fairly inefficient
if self.args[0].subs(x, 0) != 0:
return super()._eval_nseries(x, n, logx)
baseseries = self._trigfunc(x)._eval_nseries(x, n, logx)
if self._trigfunc(0) != 0:
baseseries -= 1
baseseries = baseseries.replace(Pow, lambda t, n: t**n/n, simultaneous=False)
if self._trigfunc(0) != 0:
baseseries += EulerGamma + log(x)
return baseseries.subs(x, self.args[0])._eval_nseries(x, n, logx)
class Si(TrigonometricIntegral):
r"""
Sine integral.
Explanation
===========
This function is defined by
.. math:: \operatorname{Si}(z) = \int_0^z \frac{\sin{t}}{t} \mathrm{d}t.
It is an entire function.
Examples
========
>>> from sympy import Si
>>> from sympy.abc import z
The sine integral is an antiderivative of $sin(z)/z$:
>>> Si(z).diff(z)
sin(z)/z
It is unbranched:
>>> from sympy import exp_polar, I, pi
>>> Si(z*exp_polar(2*I*pi))
Si(z)
Sine integral behaves much like ordinary sine under multiplication by ``I``:
>>> Si(I*z)
I*Shi(z)
>>> Si(-z)
-Si(z)
It can also be expressed in terms of exponential integrals, but beware
that the latter is branched:
>>> from sympy import expint
>>> Si(z).rewrite(expint)
-I*(-expint(1, z*exp_polar(-I*pi/2))/2 +
expint(1, z*exp_polar(I*pi/2))/2) + pi/2
It can be rewritten in the form of sinc function (by definition):
>>> from sympy import sinc
>>> Si(z).rewrite(sinc)
Integral(sinc(_t), (_t, 0, z))
See Also
========
Ci: Cosine integral.
Shi: Hyperbolic sine integral.
Chi: Hyperbolic cosine integral.
Ei: Exponential integral.
expint: Generalised exponential integral.
sinc: unnormalized sinc function
E1: Special case of the generalised exponential integral.
li: Logarithmic integral.
Li: Offset logarithmic integral.
References
==========
.. [1] https://en.wikipedia.org/wiki/Trigonometric_integral
"""
_trigfunc = sin
_atzero = S.Zero
@classmethod
def _atinf(cls):
return pi*S.Half
@classmethod
def _atneginf(cls):
return -pi*S.Half
@classmethod
def _minusfactor(cls, z):
return -Si(z)
@classmethod
def _Ifactor(cls, z, sign):
return I*Shi(z)*sign
def _eval_rewrite_as_expint(self, z, **kwargs):
# XXX should we polarify z?
return pi/2 + (E1(polar_lift(I)*z) - E1(polar_lift(-I)*z))/2/I
def _eval_rewrite_as_Integral(self, z, **kwargs):
from sympy.integrals.integrals import Integral
t = Dummy(uniquely_named_symbol('t', [z]).name)
return Integral(sinc(t), (t, 0, z))
_eval_rewrite_as_sinc = _eval_rewrite_as_Integral
def _eval_as_leading_term(self, x, logx=None, cdir=0):
arg = self.args[0].as_leading_term(x, logx=logx, cdir=cdir)
arg0 = arg.subs(x, 0)
if arg0 is S.NaN:
arg0 = arg.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
if arg0.is_zero:
return arg
elif not arg0.is_infinite:
return self.func(arg0)
else:
return self
def _eval_aseries(self, n, args0, x, logx):
from sympy.series.order import Order
point = args0[0]
# Expansion at oo
if point is S.Infinity:
z = self.args[0]
p = [S.NegativeOne**k * factorial(2*k) / z**(2*k + 1)
for k in range(n//2 + 1)] + [Order(1/z**n, x)]
q = [S.NegativeOne**k * factorial(2*k + 1) / z**(2*(k + 1))
for k in range(n//2)] + [Order(1/z**n, x)]
return pi/2 - cos(z)*Add(*p) - sin(z)*Add(*q)
# All other points are not handled
return super(Si, self)._eval_aseries(n, args0, x, logx)
def _eval_is_zero(self):
z = self.args[0]
if z.is_zero:
return True
class Ci(TrigonometricIntegral):
r"""
Cosine integral.
Explanation
===========
This function is defined for positive $x$ by
.. math:: \operatorname{Ci}(x) = \gamma + \log{x}
+ \int_0^x \frac{\cos{t} - 1}{t} \mathrm{d}t
= -\int_x^\infty \frac{\cos{t}}{t} \mathrm{d}t,
where $\gamma$ is the Euler-Mascheroni constant.
We have
.. math:: \operatorname{Ci}(z) =
-\frac{\operatorname{E}_1\left(e^{i\pi/2} z\right)
+ \operatorname{E}_1\left(e^{-i \pi/2} z\right)}{2}
which holds for all polar $z$ and thus provides an analytic
continuation to the Riemann surface of the logarithm.
The formula also holds as stated
for $z \in \mathbb{C}$ with $\Re(z) > 0$.
By lifting to the principal branch, we obtain an analytic function on the
cut complex plane.
Examples
========
>>> from sympy import Ci
>>> from sympy.abc import z
The cosine integral is a primitive of $\cos(z)/z$:
>>> Ci(z).diff(z)
cos(z)/z
It has a logarithmic branch point at the origin:
>>> from sympy import exp_polar, I, pi
>>> Ci(z*exp_polar(2*I*pi))
Ci(z) + 2*I*pi
The cosine integral behaves somewhat like ordinary $\cos$ under
multiplication by $i$:
>>> from sympy import polar_lift
>>> Ci(polar_lift(I)*z)
Chi(z) + I*pi/2
>>> Ci(polar_lift(-1)*z)
Ci(z) + I*pi
It can also be expressed in terms of exponential integrals:
>>> from sympy import expint
>>> Ci(z).rewrite(expint)
-expint(1, z*exp_polar(-I*pi/2))/2 - expint(1, z*exp_polar(I*pi/2))/2
See Also
========
Si: Sine integral.
Shi: Hyperbolic sine integral.
Chi: Hyperbolic cosine integral.
Ei: Exponential integral.
expint: Generalised exponential integral.
E1: Special case of the generalised exponential integral.
li: Logarithmic integral.
Li: Offset logarithmic integral.
References
==========
.. [1] https://en.wikipedia.org/wiki/Trigonometric_integral
"""
_trigfunc = cos
_atzero = S.ComplexInfinity
@classmethod
def _atinf(cls):
return S.Zero
@classmethod
def _atneginf(cls):
return I*pi
@classmethod
def _minusfactor(cls, z):
return Ci(z) + I*pi
@classmethod
def _Ifactor(cls, z, sign):
return Chi(z) + I*pi/2*sign
def _eval_rewrite_as_expint(self, z, **kwargs):
return -(E1(polar_lift(I)*z) + E1(polar_lift(-I)*z))/2
def _eval_rewrite_as_Integral(self, z, **kwargs):
from sympy.integrals.integrals import Integral
t = Dummy(uniquely_named_symbol('t', [z]).name)
return S.EulerGamma + log(z) - Integral((1-cos(t))/t, (t, 0, z))
def _eval_as_leading_term(self, x, logx=None, cdir=0):
arg = self.args[0].as_leading_term(x, logx=logx, cdir=cdir)
arg0 = arg.subs(x, 0)
if arg0 is S.NaN:
arg0 = arg.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
if arg0.is_zero:
c, e = arg.as_coeff_exponent(x)
logx = log(x) if logx is None else logx
return log(c) + e*logx + EulerGamma
elif arg0.is_finite:
return self.func(arg0)
else:
return self
def _eval_aseries(self, n, args0, x, logx):
from sympy.series.order import Order
point = args0[0]
if point in (S.Infinity, S.NegativeInfinity):
z = self.args[0]
p = [S.NegativeOne**k * factorial(2*k) / z**(2*k + 1)
for k in range(n//2 + 1)] + [Order(1/z**n, x)]
q = [S.NegativeOne**k * factorial(2*k + 1) / z**(2*(k + 1))
for k in range(n//2)] + [Order(1/z**n, x)]
result = sin(z)*(Add(*p)) - cos(z)*(Add(*q))
if point is S.NegativeInfinity:
result += I*pi
return result
return super(Ci, self)._eval_aseries(n, args0, x, logx)
class Shi(TrigonometricIntegral):
r"""
Sinh integral.
Explanation
===========
This function is defined by
.. math:: \operatorname{Shi}(z) = \int_0^z \frac{\sinh{t}}{t} \mathrm{d}t.
It is an entire function.
Examples
========
>>> from sympy import Shi
>>> from sympy.abc import z
The Sinh integral is a primitive of $\sinh(z)/z$:
>>> Shi(z).diff(z)
sinh(z)/z
It is unbranched:
>>> from sympy import exp_polar, I, pi
>>> Shi(z*exp_polar(2*I*pi))
Shi(z)
The $\sinh$ integral behaves much like ordinary $\sinh$ under
multiplication by $i$:
>>> Shi(I*z)
I*Si(z)
>>> Shi(-z)
-Shi(z)
It can also be expressed in terms of exponential integrals, but beware
that the latter is branched:
>>> from sympy import expint
>>> Shi(z).rewrite(expint)
expint(1, z)/2 - expint(1, z*exp_polar(I*pi))/2 - I*pi/2
See Also
========
Si: Sine integral.
Ci: Cosine integral.
Chi: Hyperbolic cosine integral.
Ei: Exponential integral.
expint: Generalised exponential integral.
E1: Special case of the generalised exponential integral.
li: Logarithmic integral.
Li: Offset logarithmic integral.
References
==========
.. [1] https://en.wikipedia.org/wiki/Trigonometric_integral
"""
_trigfunc = sinh
_atzero = S.Zero
@classmethod
def _atinf(cls):
return S.Infinity
@classmethod
def _atneginf(cls):
return S.NegativeInfinity
@classmethod
def _minusfactor(cls, z):
return -Shi(z)
@classmethod
def _Ifactor(cls, z, sign):
return I*Si(z)*sign
def _eval_rewrite_as_expint(self, z, **kwargs):
# XXX should we polarify z?
return (E1(z) - E1(exp_polar(I*pi)*z))/2 - I*pi/2
def _eval_is_zero(self):
z = self.args[0]
if z.is_zero:
return True
def _eval_as_leading_term(self, x, logx=None, cdir=0):
arg = self.args[0].as_leading_term(x)
arg0 = arg.subs(x, 0)
if arg0 is S.NaN:
arg0 = arg.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
if arg0.is_zero:
return arg
elif not arg0.is_infinite:
return self.func(arg0)
else:
return self
class Chi(TrigonometricIntegral):
r"""
Cosh integral.
Explanation
===========
This function is defined for positive $x$ by
.. math:: \operatorname{Chi}(x) = \gamma + \log{x}
+ \int_0^x \frac{\cosh{t} - 1}{t} \mathrm{d}t,
where $\gamma$ is the Euler-Mascheroni constant.
We have
.. math:: \operatorname{Chi}(z) = \operatorname{Ci}\left(e^{i \pi/2}z\right)
- i\frac{\pi}{2},
which holds for all polar $z$ and thus provides an analytic
continuation to the Riemann surface of the logarithm.
By lifting to the principal branch we obtain an analytic function on the
cut complex plane.
Examples
========
>>> from sympy import Chi
>>> from sympy.abc import z
The $\cosh$ integral is a primitive of $\cosh(z)/z$:
>>> Chi(z).diff(z)
cosh(z)/z
It has a logarithmic branch point at the origin:
>>> from sympy import exp_polar, I, pi
>>> Chi(z*exp_polar(2*I*pi))
Chi(z) + 2*I*pi
The $\cosh$ integral behaves somewhat like ordinary $\cosh$ under
multiplication by $i$:
>>> from sympy import polar_lift
>>> Chi(polar_lift(I)*z)
Ci(z) + I*pi/2
>>> Chi(polar_lift(-1)*z)
Chi(z) + I*pi
It can also be expressed in terms of exponential integrals:
>>> from sympy import expint
>>> Chi(z).rewrite(expint)
-expint(1, z)/2 - expint(1, z*exp_polar(I*pi))/2 - I*pi/2
See Also
========
Si: Sine integral.
Ci: Cosine integral.
Shi: Hyperbolic sine integral.
Ei: Exponential integral.
expint: Generalised exponential integral.
E1: Special case of the generalised exponential integral.
li: Logarithmic integral.
Li: Offset logarithmic integral.
References
==========
.. [1] https://en.wikipedia.org/wiki/Trigonometric_integral
"""
_trigfunc = cosh
_atzero = S.ComplexInfinity
@classmethod
def _atinf(cls):
return S.Infinity
@classmethod
def _atneginf(cls):
return S.Infinity
@classmethod
def _minusfactor(cls, z):
return Chi(z) + I*pi
@classmethod
def _Ifactor(cls, z, sign):
return Ci(z) + I*pi/2*sign
def _eval_rewrite_as_expint(self, z, **kwargs):
return -I*pi/2 - (E1(z) + E1(exp_polar(I*pi)*z))/2
def _eval_as_leading_term(self, x, logx=None, cdir=0):
arg = self.args[0].as_leading_term(x, logx=logx, cdir=cdir)
arg0 = arg.subs(x, 0)
if arg0 is S.NaN:
arg0 = arg.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
if arg0.is_zero:
c, e = arg.as_coeff_exponent(x)
logx = log(x) if logx is None else logx
return log(c) + e*logx + EulerGamma
elif arg0.is_finite:
return self.func(arg0)
else:
return self
###############################################################################
#################### FRESNEL INTEGRALS ########################################
###############################################################################
class FresnelIntegral(Function):
""" Base class for the Fresnel integrals."""
unbranched = True
@classmethod
def eval(cls, z):
# Values at positive infinities signs
# if any were extracted automatically
if z is S.Infinity:
return S.Half
# Value at zero
if z.is_zero:
return S.Zero
# Try to pull out factors of -1 and I
prefact = S.One
newarg = z
changed = False
nz = newarg.extract_multiplicatively(-1)
if nz is not None:
prefact = -prefact
newarg = nz
changed = True
nz = newarg.extract_multiplicatively(I)
if nz is not None:
prefact = cls._sign*I*prefact
newarg = nz
changed = True
if changed:
return prefact*cls(newarg)
def fdiff(self, argindex=1):
if argindex == 1:
return self._trigfunc(S.Half*pi*self.args[0]**2)
else:
raise ArgumentIndexError(self, argindex)
def _eval_is_extended_real(self):
return self.args[0].is_extended_real
_eval_is_finite = _eval_is_extended_real
def _eval_is_zero(self):
return self.args[0].is_zero
def _eval_conjugate(self):
return self.func(self.args[0].conjugate())
as_real_imag = real_to_real_as_real_imag
class fresnels(FresnelIntegral):
r"""
Fresnel integral S.
Explanation
===========
This function is defined by
.. math:: \operatorname{S}(z) = \int_0^z \sin{\frac{\pi}{2} t^2} \mathrm{d}t.
It is an entire function.
Examples
========
>>> from sympy import I, oo, fresnels
>>> from sympy.abc import z
Several special values are known:
>>> fresnels(0)
0
>>> fresnels(oo)
1/2
>>> fresnels(-oo)
-1/2
>>> fresnels(I*oo)
-I/2
>>> fresnels(-I*oo)
I/2
In general one can pull out factors of -1 and $i$ from the argument:
>>> fresnels(-z)
-fresnels(z)
>>> fresnels(I*z)
-I*fresnels(z)
The Fresnel S integral obeys the mirror symmetry
$\overline{S(z)} = S(\bar{z})$:
>>> from sympy import conjugate
>>> conjugate(fresnels(z))
fresnels(conjugate(z))
Differentiation with respect to $z$ is supported:
>>> from sympy import diff
>>> diff(fresnels(z), z)
sin(pi*z**2/2)
Defining the Fresnel functions via an integral:
>>> from sympy import integrate, pi, sin, expand_func
>>> integrate(sin(pi*z**2/2), z)
3*fresnels(z)*gamma(3/4)/(4*gamma(7/4))
>>> expand_func(integrate(sin(pi*z**2/2), z))
fresnels(z)
We can numerically evaluate the Fresnel integral to arbitrary precision
on the whole complex plane:
>>> fresnels(2).evalf(30)
0.343415678363698242195300815958
>>> fresnels(-2*I).evalf(30)
0.343415678363698242195300815958*I
See Also
========
fresnelc: Fresnel cosine integral.
References
==========
.. [1] https://en.wikipedia.org/wiki/Fresnel_integral
.. [2] https://dlmf.nist.gov/7
.. [3] https://mathworld.wolfram.com/FresnelIntegrals.html
.. [4] https://functions.wolfram.com/GammaBetaErf/FresnelS
.. [5] The converging factors for the fresnel integrals
by John W. Wrench Jr. and Vicki Alley
"""
_trigfunc = sin
_sign = -S.One
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
if n < 0:
return S.Zero
else:
x = sympify(x)
if len(previous_terms) > 1:
p = previous_terms[-1]
return (-pi**2*x**4*(4*n - 1)/(8*n*(2*n + 1)*(4*n + 3))) * p
else:
return x**3 * (-x**4)**n * (S(2)**(-2*n - 1)*pi**(2*n + 1)) / ((4*n + 3)*factorial(2*n + 1))
def _eval_rewrite_as_erf(self, z, **kwargs):
return (S.One + I)/4 * (erf((S.One + I)/2*sqrt(pi)*z) - I*erf((S.One - I)/2*sqrt(pi)*z))
def _eval_rewrite_as_hyper(self, z, **kwargs):
return pi*z**3/6 * hyper([Rational(3, 4)], [Rational(3, 2), Rational(7, 4)], -pi**2*z**4/16)
def _eval_rewrite_as_meijerg(self, z, **kwargs):
return (pi*z**Rational(9, 4) / (sqrt(2)*(z**2)**Rational(3, 4)*(-z)**Rational(3, 4))
* meijerg([], [1], [Rational(3, 4)], [Rational(1, 4), 0], -pi**2*z**4/16))
def _eval_rewrite_as_Integral(self, z, **kwargs):
from sympy.integrals.integrals import Integral
t = Dummy(uniquely_named_symbol('t', [z]).name)
return Integral(sin(pi*t**2/2), (t, 0, z))
def _eval_as_leading_term(self, x, logx=None, cdir=0):
from sympy.series.order import Order
arg = self.args[0].as_leading_term(x, logx=logx, cdir=cdir)
arg0 = arg.subs(x, 0)
if arg0 is S.ComplexInfinity:
arg0 = arg.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
if arg0.is_zero:
return pi*arg**3/6
elif arg0 in [S.Infinity, S.NegativeInfinity]:
s = 1 if arg0 is S.Infinity else -1
return s*S.Half + Order(x, x)
else:
return self.func(arg0)
def _eval_aseries(self, n, args0, x, logx):
from sympy.series.order import Order
point = args0[0]
# Expansion at oo and -oo
if point in [S.Infinity, -S.Infinity]:
z = self.args[0]
# expansion of S(x) = S1(x*sqrt(pi/2)), see reference[5] page 1-8
# as only real infinities are dealt with, sin and cos are O(1)
p = [S.NegativeOne**k * factorial(4*k + 1) /
(2**(2*k + 2) * z**(4*k + 3) * 2**(2*k)*factorial(2*k))
for k in range(0, n) if 4*k + 3 < n]
q = [1/(2*z)] + [S.NegativeOne**k * factorial(4*k - 1) /
(2**(2*k + 1) * z**(4*k + 1) * 2**(2*k - 1)*factorial(2*k - 1))
for k in range(1, n) if 4*k + 1 < n]
p = [-sqrt(2/pi)*t for t in p]
q = [-sqrt(2/pi)*t for t in q]
s = 1 if point is S.Infinity else -1
# The expansion at oo is 1/2 + some odd powers of z
# To get the expansion at -oo, replace z by -z and flip the sign
# The result -1/2 + the same odd powers of z as before.
return s*S.Half + (sin(z**2)*Add(*p) + cos(z**2)*Add(*q)
).subs(x, sqrt(2/pi)*x) + Order(1/z**n, x)
# All other points are not handled
return super()._eval_aseries(n, args0, x, logx)
class fresnelc(FresnelIntegral):
r"""
Fresnel integral C.
Explanation
===========
This function is defined by
.. math:: \operatorname{C}(z) = \int_0^z \cos{\frac{\pi}{2} t^2} \mathrm{d}t.
It is an entire function.
Examples
========
>>> from sympy import I, oo, fresnelc
>>> from sympy.abc import z
Several special values are known:
>>> fresnelc(0)
0
>>> fresnelc(oo)
1/2
>>> fresnelc(-oo)
-1/2
>>> fresnelc(I*oo)
I/2
>>> fresnelc(-I*oo)
-I/2
In general one can pull out factors of -1 and $i$ from the argument:
>>> fresnelc(-z)
-fresnelc(z)
>>> fresnelc(I*z)
I*fresnelc(z)
The Fresnel C integral obeys the mirror symmetry
$\overline{C(z)} = C(\bar{z})$:
>>> from sympy import conjugate
>>> conjugate(fresnelc(z))
fresnelc(conjugate(z))
Differentiation with respect to $z$ is supported:
>>> from sympy import diff
>>> diff(fresnelc(z), z)
cos(pi*z**2/2)
Defining the Fresnel functions via an integral:
>>> from sympy import integrate, pi, cos, expand_func
>>> integrate(cos(pi*z**2/2), z)
fresnelc(z)*gamma(1/4)/(4*gamma(5/4))
>>> expand_func(integrate(cos(pi*z**2/2), z))
fresnelc(z)
We can numerically evaluate the Fresnel integral to arbitrary precision
on the whole complex plane:
>>> fresnelc(2).evalf(30)
0.488253406075340754500223503357
>>> fresnelc(-2*I).evalf(30)
-0.488253406075340754500223503357*I
See Also
========
fresnels: Fresnel sine integral.
References
==========
.. [1] https://en.wikipedia.org/wiki/Fresnel_integral
.. [2] https://dlmf.nist.gov/7
.. [3] https://mathworld.wolfram.com/FresnelIntegrals.html
.. [4] https://functions.wolfram.com/GammaBetaErf/FresnelC
.. [5] The converging factors for the fresnel integrals
by John W. Wrench Jr. and Vicki Alley
"""
_trigfunc = cos
_sign = S.One
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
if n < 0:
return S.Zero
else:
x = sympify(x)
if len(previous_terms) > 1:
p = previous_terms[-1]
return (-pi**2*x**4*(4*n - 3)/(8*n*(2*n - 1)*(4*n + 1))) * p
else:
return x * (-x**4)**n * (S(2)**(-2*n)*pi**(2*n)) / ((4*n + 1)*factorial(2*n))
def _eval_rewrite_as_erf(self, z, **kwargs):
return (S.One - I)/4 * (erf((S.One + I)/2*sqrt(pi)*z) + I*erf((S.One - I)/2*sqrt(pi)*z))
def _eval_rewrite_as_hyper(self, z, **kwargs):
return z * hyper([Rational(1, 4)], [S.Half, Rational(5, 4)], -pi**2*z**4/16)
def _eval_rewrite_as_meijerg(self, z, **kwargs):
return (pi*z**Rational(3, 4) / (sqrt(2)*root(z**2, 4)*root(-z, 4))
* meijerg([], [1], [Rational(1, 4)], [Rational(3, 4), 0], -pi**2*z**4/16))
def _eval_rewrite_as_Integral(self, z, **kwargs):
from sympy.integrals.integrals import Integral
t = Dummy(uniquely_named_symbol('t', [z]).name)
return Integral(cos(pi*t**2/2), (t, 0, z))
def _eval_as_leading_term(self, x, logx=None, cdir=0):
from sympy.series.order import Order
arg = self.args[0].as_leading_term(x, logx=logx, cdir=cdir)
arg0 = arg.subs(x, 0)
if arg0 is S.ComplexInfinity:
arg0 = arg.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
if arg0.is_zero:
return arg
elif arg0 in [S.Infinity, S.NegativeInfinity]:
s = 1 if arg0 is S.Infinity else -1
return s*S.Half + Order(x, x)
else:
return self.func(arg0)
def _eval_aseries(self, n, args0, x, logx):
from sympy.series.order import Order
point = args0[0]
# Expansion at oo
if point in [S.Infinity, -S.Infinity]:
z = self.args[0]
# expansion of C(x) = C1(x*sqrt(pi/2)), see reference[5] page 1-8
# as only real infinities are dealt with, sin and cos are O(1)
p = [S.NegativeOne**k * factorial(4*k + 1) /
(2**(2*k + 2) * z**(4*k + 3) * 2**(2*k)*factorial(2*k))
for k in range(n) if 4*k + 3 < n]
q = [1/(2*z)] + [S.NegativeOne**k * factorial(4*k - 1) /
(2**(2*k + 1) * z**(4*k + 1) * 2**(2*k - 1)*factorial(2*k - 1))
for k in range(1, n) if 4*k + 1 < n]
p = [-sqrt(2/pi)*t for t in p]
q = [ sqrt(2/pi)*t for t in q]
s = 1 if point is S.Infinity else -1
# The expansion at oo is 1/2 + some odd powers of z
# To get the expansion at -oo, replace z by -z and flip the sign
# The result -1/2 + the same odd powers of z as before.
return s*S.Half + (cos(z**2)*Add(*p) + sin(z**2)*Add(*q)
).subs(x, sqrt(2/pi)*x) + Order(1/z**n, x)
# All other points are not handled
return super()._eval_aseries(n, args0, x, logx)
###############################################################################
#################### HELPER FUNCTIONS #########################################
###############################################################################
class _erfs(Function):
"""
Helper function to make the $\\mathrm{erf}(z)$ function
tractable for the Gruntz algorithm.
"""
@classmethod
def eval(cls, arg):
if arg.is_zero:
return S.One
def _eval_aseries(self, n, args0, x, logx):
from sympy.series.order import Order
point = args0[0]
# Expansion at oo
if point is S.Infinity:
z = self.args[0]
l = [1/sqrt(pi) * factorial(2*k)*(-S(
4))**(-k)/factorial(k) * (1/z)**(2*k + 1) for k in range(n)]
o = Order(1/z**(2*n + 1), x)
# It is very inefficient to first add the order and then do the nseries
return (Add(*l))._eval_nseries(x, n, logx) + o
# Expansion at I*oo
t = point.extract_multiplicatively(I)
if t is S.Infinity:
z = self.args[0]
# TODO: is the series really correct?
l = [1/sqrt(pi) * factorial(2*k)*(-S(
4))**(-k)/factorial(k) * (1/z)**(2*k + 1) for k in range(n)]
o = Order(1/z**(2*n + 1), x)
# It is very inefficient to first add the order and then do the nseries
return (Add(*l))._eval_nseries(x, n, logx) + o
# All other points are not handled
return super()._eval_aseries(n, args0, x, logx)
def fdiff(self, argindex=1):
if argindex == 1:
z = self.args[0]
return -2/sqrt(pi) + 2*z*_erfs(z)
else:
raise ArgumentIndexError(self, argindex)
def _eval_rewrite_as_intractable(self, z, **kwargs):
return (S.One - erf(z))*exp(z**2)
class _eis(Function):
"""
Helper function to make the $\\mathrm{Ei}(z)$ and $\\mathrm{li}(z)$
functions tractable for the Gruntz algorithm.
"""
def _eval_aseries(self, n, args0, x, logx):
from sympy.series.order import Order
if args0[0] != S.Infinity:
return super(_erfs, self)._eval_aseries(n, args0, x, logx)
z = self.args[0]
l = [factorial(k) * (1/z)**(k + 1) for k in range(n)]
o = Order(1/z**(n + 1), x)
# It is very inefficient to first add the order and then do the nseries
return (Add(*l))._eval_nseries(x, n, logx) + o
def fdiff(self, argindex=1):
if argindex == 1:
z = self.args[0]
return S.One / z - _eis(z)
else:
raise ArgumentIndexError(self, argindex)
def _eval_rewrite_as_intractable(self, z, **kwargs):
return exp(-z)*Ei(z)
def _eval_as_leading_term(self, x, logx=None, cdir=0):
x0 = self.args[0].limit(x, 0)
if x0.is_zero:
f = self._eval_rewrite_as_intractable(*self.args)
return f._eval_as_leading_term(x, logx=logx, cdir=cdir)
return super()._eval_as_leading_term(x, logx=logx, cdir=cdir)
def _eval_nseries(self, x, n, logx, cdir=0):
x0 = self.args[0].limit(x, 0)
if x0.is_zero:
f = self._eval_rewrite_as_intractable(*self.args)
return f._eval_nseries(x, n, logx)
return super()._eval_nseries(x, n, logx)
PK ]ZZZQתB�� �� * sympy/functions/special/gamma_functions.pyfrom math import prod
from sympy.core import Add, S, Dummy, expand_func
from sympy.core.expr import Expr
from sympy.core.function import Function, ArgumentIndexError, PoleError
from sympy.core.logic import fuzzy_and, fuzzy_not
from sympy.core.numbers import Rational, pi, oo, I
from sympy.core.power import Pow
from sympy.functions.special.zeta_functions import zeta
from sympy.functions.special.error_functions import erf, erfc, Ei
from sympy.functions.elementary.complexes import re, unpolarify
from sympy.functions.elementary.exponential import exp, log
from sympy.functions.elementary.integers import ceiling, floor
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.elementary.trigonometric import sin, cos, cot
from sympy.functions.combinatorial.numbers import bernoulli, harmonic
from sympy.functions.combinatorial.factorials import factorial, rf, RisingFactorial
from sympy.utilities.misc import as_int
from mpmath import mp, workprec
from mpmath.libmp.libmpf import prec_to_dps
def intlike(n):
try:
as_int(n, strict=False)
return True
except ValueError:
return False
###############################################################################
############################ COMPLETE GAMMA FUNCTION ##########################
###############################################################################
class gamma(Function):
r"""
The gamma function
.. math::
\Gamma(x) := \int^{\infty}_{0} t^{x-1} e^{-t} \mathrm{d}t.
Explanation
===========
The ``gamma`` function implements the function which passes through the
values of the factorial function (i.e., $\Gamma(n) = (n - 1)!$ when n is
an integer). More generally, $\Gamma(z)$ is defined in the whole complex
plane except at the negative integers where there are simple poles.
Examples
========
>>> from sympy import S, I, pi, gamma
>>> from sympy.abc import x
Several special values are known:
>>> gamma(1)
1
>>> gamma(4)
6
>>> gamma(S(3)/2)
sqrt(pi)/2
The ``gamma`` function obeys the mirror symmetry:
>>> from sympy import conjugate
>>> conjugate(gamma(x))
gamma(conjugate(x))
Differentiation with respect to $x$ is supported:
>>> from sympy import diff
>>> diff(gamma(x), x)
gamma(x)*polygamma(0, x)
Series expansion is also supported:
>>> from sympy import series
>>> series(gamma(x), x, 0, 3)
1/x - EulerGamma + x*(EulerGamma**2/2 + pi**2/12) + x**2*(-EulerGamma*pi**2/12 - zeta(3)/3 - EulerGamma**3/6) + O(x**3)
We can numerically evaluate the ``gamma`` function to arbitrary precision
on the whole complex plane:
>>> gamma(pi).evalf(40)
2.288037795340032417959588909060233922890
>>> gamma(1+I).evalf(20)
0.49801566811835604271 - 0.15494982830181068512*I
See Also
========
lowergamma: Lower incomplete gamma function.
uppergamma: Upper incomplete gamma function.
polygamma: Polygamma function.
loggamma: Log Gamma function.
digamma: Digamma function.
trigamma: Trigamma function.
sympy.functions.special.beta_functions.beta: Euler Beta function.
References
==========
.. [1] https://en.wikipedia.org/wiki/Gamma_function
.. [2] https://dlmf.nist.gov/5
.. [3] https://mathworld.wolfram.com/GammaFunction.html
.. [4] https://functions.wolfram.com/GammaBetaErf/Gamma/
"""
unbranched = True
_singularities = (S.ComplexInfinity,)
def fdiff(self, argindex=1):
if argindex == 1:
return self.func(self.args[0])*polygamma(0, self.args[0])
else:
raise ArgumentIndexError(self, argindex)
@classmethod
def eval(cls, arg):
if arg.is_Number:
if arg is S.NaN:
return S.NaN
elif arg is oo:
return oo
elif intlike(arg):
if arg.is_positive:
return factorial(arg - 1)
else:
return S.ComplexInfinity
elif arg.is_Rational:
if arg.q == 2:
n = abs(arg.p) // arg.q
if arg.is_positive:
k, coeff = n, S.One
else:
n = k = n + 1
if n & 1 == 0:
coeff = S.One
else:
coeff = S.NegativeOne
coeff *= prod(range(3, 2*k, 2))
if arg.is_positive:
return coeff*sqrt(pi) / 2**n
else:
return 2**n*sqrt(pi) / coeff
def _eval_expand_func(self, **hints):
arg = self.args[0]
if arg.is_Rational:
if abs(arg.p) > arg.q:
x = Dummy('x')
n = arg.p // arg.q
p = arg.p - n*arg.q
return self.func(x + n)._eval_expand_func().subs(x, Rational(p, arg.q))
if arg.is_Add:
coeff, tail = arg.as_coeff_add()
if coeff and coeff.q != 1:
intpart = floor(coeff)
tail = (coeff - intpart,) + tail
coeff = intpart
tail = arg._new_rawargs(*tail, reeval=False)
return self.func(tail)*RisingFactorial(tail, coeff)
return self.func(*self.args)
def _eval_conjugate(self):
return self.func(self.args[0].conjugate())
def _eval_is_real(self):
x = self.args[0]
if x.is_nonpositive and x.is_integer:
return False
if intlike(x) and x <= 0:
return False
if x.is_positive or x.is_noninteger:
return True
def _eval_is_positive(self):
x = self.args[0]
if x.is_positive:
return True
elif x.is_noninteger:
return floor(x).is_even
def _eval_rewrite_as_tractable(self, z, limitvar=None, **kwargs):
return exp(loggamma(z))
def _eval_rewrite_as_factorial(self, z, **kwargs):
return factorial(z - 1)
def _eval_nseries(self, x, n, logx, cdir=0):
x0 = self.args[0].limit(x, 0)
if not (x0.is_Integer and x0 <= 0):
return super()._eval_nseries(x, n, logx)
t = self.args[0] - x0
return (self.func(t + 1)/rf(self.args[0], -x0 + 1))._eval_nseries(x, n, logx)
def _eval_as_leading_term(self, x, logx=None, cdir=0):
arg = self.args[0]
x0 = arg.subs(x, 0)
if x0.is_integer and x0.is_nonpositive:
n = -x0
res = S.NegativeOne**n/self.func(n + 1)
return res/(arg + n).as_leading_term(x)
elif not x0.is_infinite:
return self.func(x0)
raise PoleError()
###############################################################################
################## LOWER and UPPER INCOMPLETE GAMMA FUNCTIONS #################
###############################################################################
class lowergamma(Function):
r"""
The lower incomplete gamma function.
Explanation
===========
It can be defined as the meromorphic continuation of
.. math::
\gamma(s, x) := \int_0^x t^{s-1} e^{-t} \mathrm{d}t = \Gamma(s) - \Gamma(s, x).
This can be shown to be the same as
.. math::
\gamma(s, x) = \frac{x^s}{s} {}_1F_1\left({s \atop s+1} \middle| -x\right),
where ${}_1F_1$ is the (confluent) hypergeometric function.
Examples
========
>>> from sympy import lowergamma, S
>>> from sympy.abc import s, x
>>> lowergamma(s, x)
lowergamma(s, x)
>>> lowergamma(3, x)
-2*(x**2/2 + x + 1)*exp(-x) + 2
>>> lowergamma(-S(1)/2, x)
-2*sqrt(pi)*erf(sqrt(x)) - 2*exp(-x)/sqrt(x)
See Also
========
gamma: Gamma function.
uppergamma: Upper incomplete gamma function.
polygamma: Polygamma function.
loggamma: Log Gamma function.
digamma: Digamma function.
trigamma: Trigamma function.
sympy.functions.special.beta_functions.beta: Euler Beta function.
References
==========
.. [1] https://en.wikipedia.org/wiki/Incomplete_gamma_function#Lower_incomplete_gamma_function
.. [2] Abramowitz, Milton; Stegun, Irene A., eds. (1965), Chapter 6,
Section 5, Handbook of Mathematical Functions with Formulas, Graphs,
and Mathematical Tables
.. [3] https://dlmf.nist.gov/8
.. [4] https://functions.wolfram.com/GammaBetaErf/Gamma2/
.. [5] https://functions.wolfram.com/GammaBetaErf/Gamma3/
"""
def fdiff(self, argindex=2):
from sympy.functions.special.hyper import meijerg
if argindex == 2:
a, z = self.args
return exp(-unpolarify(z))*z**(a - 1)
elif argindex == 1:
a, z = self.args
return gamma(a)*digamma(a) - log(z)*uppergamma(a, z) \
- meijerg([], [1, 1], [0, 0, a], [], z)
else:
raise ArgumentIndexError(self, argindex)
@classmethod
def eval(cls, a, x):
# For lack of a better place, we use this one to extract branching
# information. The following can be
# found in the literature (c/f references given above), albeit scattered:
# 1) For fixed x != 0, lowergamma(s, x) is an entire function of s
# 2) For fixed positive integers s, lowergamma(s, x) is an entire
# function of x.
# 3) For fixed non-positive integers s,
# lowergamma(s, exp(I*2*pi*n)*x) =
# 2*pi*I*n*(-1)**(-s)/factorial(-s) + lowergamma(s, x)
# (this follows from lowergamma(s, x).diff(x) = x**(s-1)*exp(-x)).
# 4) For fixed non-integral s,
# lowergamma(s, x) = x**s*gamma(s)*lowergamma_unbranched(s, x),
# where lowergamma_unbranched(s, x) is an entire function (in fact
# of both s and x), i.e.
# lowergamma(s, exp(2*I*pi*n)*x) = exp(2*pi*I*n*a)*lowergamma(a, x)
if x is S.Zero:
return S.Zero
nx, n = x.extract_branch_factor()
if a.is_integer and a.is_positive:
nx = unpolarify(x)
if nx != x:
return lowergamma(a, nx)
elif a.is_integer and a.is_nonpositive:
if n != 0:
return 2*pi*I*n*S.NegativeOne**(-a)/factorial(-a) + lowergamma(a, nx)
elif n != 0:
return exp(2*pi*I*n*a)*lowergamma(a, nx)
# Special values.
if a.is_Number:
if a is S.One:
return S.One - exp(-x)
elif a is S.Half:
return sqrt(pi)*erf(sqrt(x))
elif a.is_Integer or (2*a).is_Integer:
b = a - 1
if b.is_positive:
if a.is_integer:
return factorial(b) - exp(-x) * factorial(b) * Add(*[x ** k / factorial(k) for k in range(a)])
else:
return gamma(a)*(lowergamma(S.Half, x)/sqrt(pi) - exp(-x)*Add(*[x**(k - S.Half)/gamma(S.Half + k) for k in range(1, a + S.Half)]))
if not a.is_Integer:
return S.NegativeOne**(S.Half - a)*pi*erf(sqrt(x))/gamma(1 - a) + exp(-x)*Add(*[x**(k + a - 1)*gamma(a)/gamma(a + k) for k in range(1, Rational(3, 2) - a)])
if x.is_zero:
return S.Zero
def _eval_evalf(self, prec):
if all(x.is_number for x in self.args):
a = self.args[0]._to_mpmath(prec)
z = self.args[1]._to_mpmath(prec)
with workprec(prec):
res = mp.gammainc(a, 0, z)
return Expr._from_mpmath(res, prec)
else:
return self
def _eval_conjugate(self):
x = self.args[1]
if x not in (S.Zero, S.NegativeInfinity):
return self.func(self.args[0].conjugate(), x.conjugate())
def _eval_is_meromorphic(self, x, a):
# By https://en.wikipedia.org/wiki/Incomplete_gamma_function#Holomorphic_extension,
# lowergamma(s, z) = z**s*gamma(s)*gammastar(s, z),
# where gammastar(s, z) is holomorphic for all s and z.
# Hence the singularities of lowergamma are z = 0 (branch
# point) and nonpositive integer values of s (poles of gamma(s)).
s, z = self.args
args_merom = fuzzy_and([z._eval_is_meromorphic(x, a),
s._eval_is_meromorphic(x, a)])
if not args_merom:
return args_merom
z0 = z.subs(x, a)
if s.is_integer:
return fuzzy_and([s.is_positive, z0.is_finite])
s0 = s.subs(x, a)
return fuzzy_and([s0.is_finite, z0.is_finite, fuzzy_not(z0.is_zero)])
def _eval_aseries(self, n, args0, x, logx):
from sympy.series.order import O
s, z = self.args
if args0[0] is oo and not z.has(x):
coeff = z**s*exp(-z)
sum_expr = sum(z**k/rf(s, k + 1) for k in range(n - 1))
o = O(z**s*s**(-n))
return coeff*sum_expr + o
return super()._eval_aseries(n, args0, x, logx)
def _eval_rewrite_as_uppergamma(self, s, x, **kwargs):
return gamma(s) - uppergamma(s, x)
def _eval_rewrite_as_expint(self, s, x, **kwargs):
from sympy.functions.special.error_functions import expint
if s.is_integer and s.is_nonpositive:
return self
return self.rewrite(uppergamma).rewrite(expint)
def _eval_is_zero(self):
x = self.args[1]
if x.is_zero:
return True
class uppergamma(Function):
r"""
The upper incomplete gamma function.
Explanation
===========
It can be defined as the meromorphic continuation of
.. math::
\Gamma(s, x) := \int_x^\infty t^{s-1} e^{-t} \mathrm{d}t = \Gamma(s) - \gamma(s, x).
where $\gamma(s, x)$ is the lower incomplete gamma function,
:class:`lowergamma`. This can be shown to be the same as
.. math::
\Gamma(s, x) = \Gamma(s) - \frac{x^s}{s} {}_1F_1\left({s \atop s+1} \middle| -x\right),
where ${}_1F_1$ is the (confluent) hypergeometric function.
The upper incomplete gamma function is also essentially equivalent to the
generalized exponential integral:
.. math::
\operatorname{E}_{n}(x) = \int_{1}^{\infty}{\frac{e^{-xt}}{t^n} \, dt} = x^{n-1}\Gamma(1-n,x).
Examples
========
>>> from sympy import uppergamma, S
>>> from sympy.abc import s, x
>>> uppergamma(s, x)
uppergamma(s, x)
>>> uppergamma(3, x)
2*(x**2/2 + x + 1)*exp(-x)
>>> uppergamma(-S(1)/2, x)
-2*sqrt(pi)*erfc(sqrt(x)) + 2*exp(-x)/sqrt(x)
>>> uppergamma(-2, x)
expint(3, x)/x**2
See Also
========
gamma: Gamma function.
lowergamma: Lower incomplete gamma function.
polygamma: Polygamma function.
loggamma: Log Gamma function.
digamma: Digamma function.
trigamma: Trigamma function.
sympy.functions.special.beta_functions.beta: Euler Beta function.
References
==========
.. [1] https://en.wikipedia.org/wiki/Incomplete_gamma_function#Upper_incomplete_gamma_function
.. [2] Abramowitz, Milton; Stegun, Irene A., eds. (1965), Chapter 6,
Section 5, Handbook of Mathematical Functions with Formulas, Graphs,
and Mathematical Tables
.. [3] https://dlmf.nist.gov/8
.. [4] https://functions.wolfram.com/GammaBetaErf/Gamma2/
.. [5] https://functions.wolfram.com/GammaBetaErf/Gamma3/
.. [6] https://en.wikipedia.org/wiki/Exponential_integral#Relation_with_other_functions
"""
def fdiff(self, argindex=2):
from sympy.functions.special.hyper import meijerg
if argindex == 2:
a, z = self.args
return -exp(-unpolarify(z))*z**(a - 1)
elif argindex == 1:
a, z = self.args
return uppergamma(a, z)*log(z) + meijerg([], [1, 1], [0, 0, a], [], z)
else:
raise ArgumentIndexError(self, argindex)
def _eval_evalf(self, prec):
if all(x.is_number for x in self.args):
a = self.args[0]._to_mpmath(prec)
z = self.args[1]._to_mpmath(prec)
with workprec(prec):
res = mp.gammainc(a, z, mp.inf)
return Expr._from_mpmath(res, prec)
return self
@classmethod
def eval(cls, a, z):
from sympy.functions.special.error_functions import expint
if z.is_Number:
if z is S.NaN:
return S.NaN
elif z is oo:
return S.Zero
elif z.is_zero:
if re(a).is_positive:
return gamma(a)
# We extract branching information here. C/f lowergamma.
nx, n = z.extract_branch_factor()
if a.is_integer and a.is_positive:
nx = unpolarify(z)
if z != nx:
return uppergamma(a, nx)
elif a.is_integer and a.is_nonpositive:
if n != 0:
return -2*pi*I*n*S.NegativeOne**(-a)/factorial(-a) + uppergamma(a, nx)
elif n != 0:
return gamma(a)*(1 - exp(2*pi*I*n*a)) + exp(2*pi*I*n*a)*uppergamma(a, nx)
# Special values.
if a.is_Number:
if a is S.Zero and z.is_positive:
return -Ei(-z)
elif a is S.One:
return exp(-z)
elif a is S.Half:
return sqrt(pi)*erfc(sqrt(z))
elif a.is_Integer or (2*a).is_Integer:
b = a - 1
if b.is_positive:
if a.is_integer:
return exp(-z) * factorial(b) * Add(*[z**k / factorial(k)
for k in range(a)])
else:
return (gamma(a) * erfc(sqrt(z)) +
S.NegativeOne**(a - S(3)/2) * exp(-z) * sqrt(z)
* Add(*[gamma(-S.Half - k) * (-z)**k / gamma(1-a)
for k in range(a - S.Half)]))
elif b.is_Integer:
return expint(-b, z)*unpolarify(z)**(b + 1)
if not a.is_Integer:
return (S.NegativeOne**(S.Half - a) * pi*erfc(sqrt(z))/gamma(1-a)
- z**a * exp(-z) * Add(*[z**k * gamma(a) / gamma(a+k+1)
for k in range(S.Half - a)]))
if a.is_zero and z.is_positive:
return -Ei(-z)
if z.is_zero and re(a).is_positive:
return gamma(a)
def _eval_conjugate(self):
z = self.args[1]
if z not in (S.Zero, S.NegativeInfinity):
return self.func(self.args[0].conjugate(), z.conjugate())
def _eval_is_meromorphic(self, x, a):
return lowergamma._eval_is_meromorphic(self, x, a)
def _eval_rewrite_as_lowergamma(self, s, x, **kwargs):
return gamma(s) - lowergamma(s, x)
def _eval_rewrite_as_tractable(self, s, x, **kwargs):
return exp(loggamma(s)) - lowergamma(s, x)
def _eval_rewrite_as_expint(self, s, x, **kwargs):
from sympy.functions.special.error_functions import expint
return expint(1 - s, x)*x**s
###############################################################################
###################### POLYGAMMA and LOGGAMMA FUNCTIONS #######################
###############################################################################
class polygamma(Function):
r"""
The function ``polygamma(n, z)`` returns ``log(gamma(z)).diff(n + 1)``.
Explanation
===========
It is a meromorphic function on $\mathbb{C}$ and defined as the $(n+1)$-th
derivative of the logarithm of the gamma function:
.. math::
\psi^{(n)} (z) := \frac{\mathrm{d}^{n+1}}{\mathrm{d} z^{n+1}} \log\Gamma(z).
For `n` not a nonnegative integer the generalization by Espinosa and Moll [5]_
is used:
.. math:: \psi(s,z) = \frac{\zeta'(s+1, z) + (\gamma + \psi(-s)) \zeta(s+1, z)}
{\Gamma(-s)}
Examples
========
Several special values are known:
>>> from sympy import S, polygamma
>>> polygamma(0, 1)
-EulerGamma
>>> polygamma(0, 1/S(2))
-2*log(2) - EulerGamma
>>> polygamma(0, 1/S(3))
-log(3) - sqrt(3)*pi/6 - EulerGamma - log(sqrt(3))
>>> polygamma(0, 1/S(4))
-pi/2 - log(4) - log(2) - EulerGamma
>>> polygamma(0, 2)
1 - EulerGamma
>>> polygamma(0, 23)
19093197/5173168 - EulerGamma
>>> from sympy import oo, I
>>> polygamma(0, oo)
oo
>>> polygamma(0, -oo)
oo
>>> polygamma(0, I*oo)
oo
>>> polygamma(0, -I*oo)
oo
Differentiation with respect to $x$ is supported:
>>> from sympy import Symbol, diff
>>> x = Symbol("x")
>>> diff(polygamma(0, x), x)
polygamma(1, x)
>>> diff(polygamma(0, x), x, 2)
polygamma(2, x)
>>> diff(polygamma(0, x), x, 3)
polygamma(3, x)
>>> diff(polygamma(1, x), x)
polygamma(2, x)
>>> diff(polygamma(1, x), x, 2)
polygamma(3, x)
>>> diff(polygamma(2, x), x)
polygamma(3, x)
>>> diff(polygamma(2, x), x, 2)
polygamma(4, x)
>>> n = Symbol("n")
>>> diff(polygamma(n, x), x)
polygamma(n + 1, x)
>>> diff(polygamma(n, x), x, 2)
polygamma(n + 2, x)
We can rewrite ``polygamma`` functions in terms of harmonic numbers:
>>> from sympy import harmonic
>>> polygamma(0, x).rewrite(harmonic)
harmonic(x - 1) - EulerGamma
>>> polygamma(2, x).rewrite(harmonic)
2*harmonic(x - 1, 3) - 2*zeta(3)
>>> ni = Symbol("n", integer=True)
>>> polygamma(ni, x).rewrite(harmonic)
(-1)**(n + 1)*(-harmonic(x - 1, n + 1) + zeta(n + 1))*factorial(n)
See Also
========
gamma: Gamma function.
lowergamma: Lower incomplete gamma function.
uppergamma: Upper incomplete gamma function.
loggamma: Log Gamma function.
digamma: Digamma function.
trigamma: Trigamma function.
sympy.functions.special.beta_functions.beta: Euler Beta function.
References
==========
.. [1] https://en.wikipedia.org/wiki/Polygamma_function
.. [2] https://mathworld.wolfram.com/PolygammaFunction.html
.. [3] https://functions.wolfram.com/GammaBetaErf/PolyGamma/
.. [4] https://functions.wolfram.com/GammaBetaErf/PolyGamma2/
.. [5] O. Espinosa and V. Moll, "A generalized polygamma function",
*Integral Transforms and Special Functions* (2004), 101-115.
"""
@classmethod
def eval(cls, n, z):
if n is S.NaN or z is S.NaN:
return S.NaN
elif z is oo:
return oo if n.is_zero else S.Zero
elif z.is_Integer and z.is_nonpositive:
return S.ComplexInfinity
elif n is S.NegativeOne:
return loggamma(z) - log(2*pi) / 2
elif n.is_zero:
if z is -oo or z.extract_multiplicatively(I) in (oo, -oo):
return oo
elif z.is_Integer:
return harmonic(z-1) - S.EulerGamma
elif z.is_Rational:
# TODO n == 1 also can do some rational z
p, q = z.as_numer_denom()
# only expand for small denominators to avoid creating long expressions
if q <= 6:
return expand_func(polygamma(S.Zero, z, evaluate=False))
elif n.is_integer and n.is_nonnegative:
nz = unpolarify(z)
if z != nz:
return polygamma(n, nz)
if z.is_Integer:
return S.NegativeOne**(n+1) * factorial(n) * zeta(n+1, z)
elif z is S.Half:
return S.NegativeOne**(n+1) * factorial(n) * (2**(n+1)-1) * zeta(n+1)
def _eval_is_real(self):
if self.args[0].is_positive and self.args[1].is_positive:
return True
def _eval_is_complex(self):
z = self.args[1]
is_negative_integer = fuzzy_and([z.is_negative, z.is_integer])
return fuzzy_and([z.is_complex, fuzzy_not(is_negative_integer)])
def _eval_is_positive(self):
n, z = self.args
if n.is_positive:
if n.is_odd and z.is_real:
return True
if n.is_even and z.is_positive:
return False
def _eval_is_negative(self):
n, z = self.args
if n.is_positive:
if n.is_even and z.is_positive:
return True
if n.is_odd and z.is_real:
return False
def _eval_expand_func(self, **hints):
n, z = self.args
if n.is_Integer and n.is_nonnegative:
if z.is_Add:
coeff = z.args[0]
if coeff.is_Integer:
e = -(n + 1)
if coeff > 0:
tail = Add(*[Pow(
z - i, e) for i in range(1, int(coeff) + 1)])
else:
tail = -Add(*[Pow(
z + i, e) for i in range(int(-coeff))])
return polygamma(n, z - coeff) + S.NegativeOne**n*factorial(n)*tail
elif z.is_Mul:
coeff, z = z.as_two_terms()
if coeff.is_Integer and coeff.is_positive:
tail = [polygamma(n, z + Rational(
i, coeff)) for i in range(int(coeff))]
if n == 0:
return Add(*tail)/coeff + log(coeff)
else:
return Add(*tail)/coeff**(n + 1)
z *= coeff
if n == 0 and z.is_Rational:
p, q = z.as_numer_denom()
# Reference:
# Values of the polygamma functions at rational arguments, J. Choi, 2007
part_1 = -S.EulerGamma - pi * cot(p * pi / q) / 2 - log(q) + Add(
*[cos(2 * k * pi * p / q) * log(2 * sin(k * pi / q)) for k in range(1, q)])
if z > 0:
n = floor(z)
z0 = z - n
return part_1 + Add(*[1 / (z0 + k) for k in range(n)])
elif z < 0:
n = floor(1 - z)
z0 = z + n
return part_1 - Add(*[1 / (z0 - 1 - k) for k in range(n)])
if n == -1:
return loggamma(z) - log(2*pi) / 2
if n.is_integer is False or n.is_nonnegative is False:
s = Dummy("s")
dzt = zeta(s, z).diff(s).subs(s, n+1)
return (dzt + (S.EulerGamma + digamma(-n)) * zeta(n+1, z)) / gamma(-n)
return polygamma(n, z)
def _eval_rewrite_as_zeta(self, n, z, **kwargs):
if n.is_integer and n.is_positive:
return S.NegativeOne**(n + 1)*factorial(n)*zeta(n + 1, z)
def _eval_rewrite_as_harmonic(self, n, z, **kwargs):
if n.is_integer:
if n.is_zero:
return harmonic(z - 1) - S.EulerGamma
else:
return S.NegativeOne**(n+1) * factorial(n) * (zeta(n+1) - harmonic(z-1, n+1))
def _eval_as_leading_term(self, x, logx=None, cdir=0):
from sympy.series.order import Order
n, z = [a.as_leading_term(x) for a in self.args]
o = Order(z, x)
if n == 0 and o.contains(1/x):
logx = log(x) if logx is None else logx
return o.getn() * logx
else:
return self.func(n, z)
def fdiff(self, argindex=2):
if argindex == 2:
n, z = self.args[:2]
return polygamma(n + 1, z)
else:
raise ArgumentIndexError(self, argindex)
def _eval_aseries(self, n, args0, x, logx):
from sympy.series.order import Order
if args0[1] != oo or not \
(self.args[0].is_Integer and self.args[0].is_nonnegative):
return super()._eval_aseries(n, args0, x, logx)
z = self.args[1]
N = self.args[0]
if N == 0:
# digamma function series
# Abramowitz & Stegun, p. 259, 6.3.18
r = log(z) - 1/(2*z)
o = None
if n < 2:
o = Order(1/z, x)
else:
m = ceiling((n + 1)//2)
l = [bernoulli(2*k) / (2*k*z**(2*k)) for k in range(1, m)]
r -= Add(*l)
o = Order(1/z**n, x)
return r._eval_nseries(x, n, logx) + o
else:
# proper polygamma function
# Abramowitz & Stegun, p. 260, 6.4.10
# We return terms to order higher than O(x**n) on purpose
# -- otherwise we would not be able to return any terms for
# quite a long time!
fac = gamma(N)
e0 = fac + N*fac/(2*z)
m = ceiling((n + 1)//2)
for k in range(1, m):
fac = fac*(2*k + N - 1)*(2*k + N - 2) / ((2*k)*(2*k - 1))
e0 += bernoulli(2*k)*fac/z**(2*k)
o = Order(1/z**(2*m), x)
if n == 0:
o = Order(1/z, x)
elif n == 1:
o = Order(1/z**2, x)
r = e0._eval_nseries(z, n, logx) + o
return (-1 * (-1/z)**N * r)._eval_nseries(x, n, logx)
def _eval_evalf(self, prec):
if not all(i.is_number for i in self.args):
return
s = self.args[0]._to_mpmath(prec+12)
z = self.args[1]._to_mpmath(prec+12)
if mp.isint(z) and z <= 0:
return S.ComplexInfinity
with workprec(prec+12):
if mp.isint(s) and s >= 0:
res = mp.polygamma(s, z)
else:
zt = mp.zeta(s+1, z)
dzt = mp.zeta(s+1, z, 1)
res = (dzt + (mp.euler + mp.digamma(-s)) * zt) * mp.rgamma(-s)
return Expr._from_mpmath(res, prec)
class loggamma(Function):
r"""
The ``loggamma`` function implements the logarithm of the
gamma function (i.e., $\log\Gamma(x)$).
Examples
========
Several special values are known. For numerical integral
arguments we have:
>>> from sympy import loggamma
>>> loggamma(-2)
oo
>>> loggamma(0)
oo
>>> loggamma(1)
0
>>> loggamma(2)
0
>>> loggamma(3)
log(2)
And for symbolic values:
>>> from sympy import Symbol
>>> n = Symbol("n", integer=True, positive=True)
>>> loggamma(n)
log(gamma(n))
>>> loggamma(-n)
oo
For half-integral values:
>>> from sympy import S
>>> loggamma(S(5)/2)
log(3*sqrt(pi)/4)
>>> loggamma(n/2)
log(2**(1 - n)*sqrt(pi)*gamma(n)/gamma(n/2 + 1/2))
And general rational arguments:
>>> from sympy import expand_func
>>> L = loggamma(S(16)/3)
>>> expand_func(L).doit()
-5*log(3) + loggamma(1/3) + log(4) + log(7) + log(10) + log(13)
>>> L = loggamma(S(19)/4)
>>> expand_func(L).doit()
-4*log(4) + loggamma(3/4) + log(3) + log(7) + log(11) + log(15)
>>> L = loggamma(S(23)/7)
>>> expand_func(L).doit()
-3*log(7) + log(2) + loggamma(2/7) + log(9) + log(16)
The ``loggamma`` function has the following limits towards infinity:
>>> from sympy import oo
>>> loggamma(oo)
oo
>>> loggamma(-oo)
zoo
The ``loggamma`` function obeys the mirror symmetry
if $x \in \mathbb{C} \setminus \{-\infty, 0\}$:
>>> from sympy.abc import x
>>> from sympy import conjugate
>>> conjugate(loggamma(x))
loggamma(conjugate(x))
Differentiation with respect to $x$ is supported:
>>> from sympy import diff
>>> diff(loggamma(x), x)
polygamma(0, x)
Series expansion is also supported:
>>> from sympy import series
>>> series(loggamma(x), x, 0, 4).cancel()
-log(x) - EulerGamma*x + pi**2*x**2/12 - x**3*zeta(3)/3 + O(x**4)
We can numerically evaluate the ``loggamma`` function
to arbitrary precision on the whole complex plane:
>>> from sympy import I
>>> loggamma(5).evalf(30)
3.17805383034794561964694160130
>>> loggamma(I).evalf(20)
-0.65092319930185633889 - 1.8724366472624298171*I
See Also
========
gamma: Gamma function.
lowergamma: Lower incomplete gamma function.
uppergamma: Upper incomplete gamma function.
polygamma: Polygamma function.
digamma: Digamma function.
trigamma: Trigamma function.
sympy.functions.special.beta_functions.beta: Euler Beta function.
References
==========
.. [1] https://en.wikipedia.org/wiki/Gamma_function
.. [2] https://dlmf.nist.gov/5
.. [3] https://mathworld.wolfram.com/LogGammaFunction.html
.. [4] https://functions.wolfram.com/GammaBetaErf/LogGamma/
"""
@classmethod
def eval(cls, z):
if z.is_integer:
if z.is_nonpositive:
return oo
elif z.is_positive:
return log(gamma(z))
elif z.is_rational:
p, q = z.as_numer_denom()
# Half-integral values:
if p.is_positive and q == 2:
return log(sqrt(pi) * 2**(1 - p) * gamma(p) / gamma((p + 1)*S.Half))
if z is oo:
return oo
elif abs(z) is oo:
return S.ComplexInfinity
if z is S.NaN:
return S.NaN
def _eval_expand_func(self, **hints):
from sympy.concrete.summations import Sum
z = self.args[0]
if z.is_Rational:
p, q = z.as_numer_denom()
# General rational arguments (u + p/q)
# Split z as n + p/q with p < q
n = p // q
p = p - n*q
if p.is_positive and q.is_positive and p < q:
k = Dummy("k")
if n.is_positive:
return loggamma(p / q) - n*log(q) + Sum(log((k - 1)*q + p), (k, 1, n))
elif n.is_negative:
return loggamma(p / q) - n*log(q) + pi*I*n - Sum(log(k*q - p), (k, 1, -n))
elif n.is_zero:
return loggamma(p / q)
return self
def _eval_nseries(self, x, n, logx=None, cdir=0):
x0 = self.args[0].limit(x, 0)
if x0.is_zero:
f = self._eval_rewrite_as_intractable(*self.args)
return f._eval_nseries(x, n, logx)
return super()._eval_nseries(x, n, logx)
def _eval_aseries(self, n, args0, x, logx):
from sympy.series.order import Order
if args0[0] != oo:
return super()._eval_aseries(n, args0, x, logx)
z = self.args[0]
r = log(z)*(z - S.Half) - z + log(2*pi)/2
l = [bernoulli(2*k) / (2*k*(2*k - 1)*z**(2*k - 1)) for k in range(1, n)]
o = None
if n == 0:
o = Order(1, x)
else:
o = Order(1/z**n, x)
# It is very inefficient to first add the order and then do the nseries
return (r + Add(*l))._eval_nseries(x, n, logx) + o
def _eval_rewrite_as_intractable(self, z, **kwargs):
return log(gamma(z))
def _eval_is_real(self):
z = self.args[0]
if z.is_positive:
return True
elif z.is_nonpositive:
return False
def _eval_conjugate(self):
z = self.args[0]
if z not in (S.Zero, S.NegativeInfinity):
return self.func(z.conjugate())
def fdiff(self, argindex=1):
if argindex == 1:
return polygamma(0, self.args[0])
else:
raise ArgumentIndexError(self, argindex)
class digamma(Function):
r"""
The ``digamma`` function is the first derivative of the ``loggamma``
function
.. math::
\psi(x) := \frac{\mathrm{d}}{\mathrm{d} z} \log\Gamma(z)
= \frac{\Gamma'(z)}{\Gamma(z) }.
In this case, ``digamma(z) = polygamma(0, z)``.
Examples
========
>>> from sympy import digamma
>>> digamma(0)
zoo
>>> from sympy import Symbol
>>> z = Symbol('z')
>>> digamma(z)
polygamma(0, z)
To retain ``digamma`` as it is:
>>> digamma(0, evaluate=False)
digamma(0)
>>> digamma(z, evaluate=False)
digamma(z)
See Also
========
gamma: Gamma function.
lowergamma: Lower incomplete gamma function.
uppergamma: Upper incomplete gamma function.
polygamma: Polygamma function.
loggamma: Log Gamma function.
trigamma: Trigamma function.
sympy.functions.special.beta_functions.beta: Euler Beta function.
References
==========
.. [1] https://en.wikipedia.org/wiki/Digamma_function
.. [2] https://mathworld.wolfram.com/DigammaFunction.html
.. [3] https://functions.wolfram.com/GammaBetaErf/PolyGamma2/
"""
def _eval_evalf(self, prec):
z = self.args[0]
nprec = prec_to_dps(prec)
return polygamma(0, z).evalf(n=nprec)
def fdiff(self, argindex=1):
z = self.args[0]
return polygamma(0, z).fdiff()
def _eval_is_real(self):
z = self.args[0]
return polygamma(0, z).is_real
def _eval_is_positive(self):
z = self.args[0]
return polygamma(0, z).is_positive
def _eval_is_negative(self):
z = self.args[0]
return polygamma(0, z).is_negative
def _eval_aseries(self, n, args0, x, logx):
as_polygamma = self.rewrite(polygamma)
args0 = [S.Zero,] + args0
return as_polygamma._eval_aseries(n, args0, x, logx)
@classmethod
def eval(cls, z):
return polygamma(0, z)
def _eval_expand_func(self, **hints):
z = self.args[0]
return polygamma(0, z).expand(func=True)
def _eval_rewrite_as_harmonic(self, z, **kwargs):
return harmonic(z - 1) - S.EulerGamma
def _eval_rewrite_as_polygamma(self, z, **kwargs):
return polygamma(0, z)
def _eval_as_leading_term(self, x, logx=None, cdir=0):
z = self.args[0]
return polygamma(0, z).as_leading_term(x)
class trigamma(Function):
r"""
The ``trigamma`` function is the second derivative of the ``loggamma``
function
.. math::
\psi^{(1)}(z) := \frac{\mathrm{d}^{2}}{\mathrm{d} z^{2}} \log\Gamma(z).
In this case, ``trigamma(z) = polygamma(1, z)``.
Examples
========
>>> from sympy import trigamma
>>> trigamma(0)
zoo
>>> from sympy import Symbol
>>> z = Symbol('z')
>>> trigamma(z)
polygamma(1, z)
To retain ``trigamma`` as it is:
>>> trigamma(0, evaluate=False)
trigamma(0)
>>> trigamma(z, evaluate=False)
trigamma(z)
See Also
========
gamma: Gamma function.
lowergamma: Lower incomplete gamma function.
uppergamma: Upper incomplete gamma function.
polygamma: Polygamma function.
loggamma: Log Gamma function.
digamma: Digamma function.
sympy.functions.special.beta_functions.beta: Euler Beta function.
References
==========
.. [1] https://en.wikipedia.org/wiki/Trigamma_function
.. [2] https://mathworld.wolfram.com/TrigammaFunction.html
.. [3] https://functions.wolfram.com/GammaBetaErf/PolyGamma2/
"""
def _eval_evalf(self, prec):
z = self.args[0]
nprec = prec_to_dps(prec)
return polygamma(1, z).evalf(n=nprec)
def fdiff(self, argindex=1):
z = self.args[0]
return polygamma(1, z).fdiff()
def _eval_is_real(self):
z = self.args[0]
return polygamma(1, z).is_real
def _eval_is_positive(self):
z = self.args[0]
return polygamma(1, z).is_positive
def _eval_is_negative(self):
z = self.args[0]
return polygamma(1, z).is_negative
def _eval_aseries(self, n, args0, x, logx):
as_polygamma = self.rewrite(polygamma)
args0 = [S.One,] + args0
return as_polygamma._eval_aseries(n, args0, x, logx)
@classmethod
def eval(cls, z):
return polygamma(1, z)
def _eval_expand_func(self, **hints):
z = self.args[0]
return polygamma(1, z).expand(func=True)
def _eval_rewrite_as_zeta(self, z, **kwargs):
return zeta(2, z)
def _eval_rewrite_as_polygamma(self, z, **kwargs):
return polygamma(1, z)
def _eval_rewrite_as_harmonic(self, z, **kwargs):
return -harmonic(z - 1, 2) + pi**2 / 6
def _eval_as_leading_term(self, x, logx=None, cdir=0):
z = self.args[0]
return polygamma(1, z).as_leading_term(x)
###############################################################################
##################### COMPLETE MULTIVARIATE GAMMA FUNCTION ####################
###############################################################################
class multigamma(Function):
r"""
The multivariate gamma function is a generalization of the gamma function
.. math::
\Gamma_p(z) = \pi^{p(p-1)/4}\prod_{k=1}^p \Gamma[z + (1 - k)/2].
In a special case, ``multigamma(x, 1) = gamma(x)``.
Examples
========
>>> from sympy import S, multigamma
>>> from sympy import Symbol
>>> x = Symbol('x')
>>> p = Symbol('p', positive=True, integer=True)
>>> multigamma(x, p)
pi**(p*(p - 1)/4)*Product(gamma(-_k/2 + x + 1/2), (_k, 1, p))
Several special values are known:
>>> multigamma(1, 1)
1
>>> multigamma(4, 1)
6
>>> multigamma(S(3)/2, 1)
sqrt(pi)/2
Writing ``multigamma`` in terms of the ``gamma`` function:
>>> multigamma(x, 1)
gamma(x)
>>> multigamma(x, 2)
sqrt(pi)*gamma(x)*gamma(x - 1/2)
>>> multigamma(x, 3)
pi**(3/2)*gamma(x)*gamma(x - 1)*gamma(x - 1/2)
Parameters
==========
p : order or dimension of the multivariate gamma function
See Also
========
gamma, lowergamma, uppergamma, polygamma, loggamma, digamma, trigamma,
sympy.functions.special.beta_functions.beta
References
==========
.. [1] https://en.wikipedia.org/wiki/Multivariate_gamma_function
"""
unbranched = True
def fdiff(self, argindex=2):
from sympy.concrete.summations import Sum
if argindex == 2:
x, p = self.args
k = Dummy("k")
return self.func(x, p)*Sum(polygamma(0, x + (1 - k)/2), (k, 1, p))
else:
raise ArgumentIndexError(self, argindex)
@classmethod
def eval(cls, x, p):
from sympy.concrete.products import Product
if p.is_positive is False or p.is_integer is False:
raise ValueError('Order parameter p must be positive integer.')
k = Dummy("k")
return (pi**(p*(p - 1)/4)*Product(gamma(x + (1 - k)/2),
(k, 1, p))).doit()
def _eval_conjugate(self):
x, p = self.args
return self.func(x.conjugate(), p)
def _eval_is_real(self):
x, p = self.args
y = 2*x
if y.is_integer and (y <= (p - 1)) is True:
return False
if intlike(y) and (y <= (p - 1)):
return False
if y > (p - 1) or y.is_noninteger:
return True
PK ]ZZZ�U�ǡ� �� sympy/functions/special/hyper.py"""Hypergeometric and Meijer G-functions"""
from collections import Counter
from sympy.core import S, Mod
from sympy.core.add import Add
from sympy.core.expr import Expr
from sympy.core.function import Function, Derivative, ArgumentIndexError
from sympy.core.containers import Tuple
from sympy.core.mul import Mul
from sympy.core.numbers import I, pi, oo, zoo
from sympy.core.parameters import global_parameters
from sympy.core.relational import Ne
from sympy.core.sorting import default_sort_key
from sympy.core.symbol import Dummy
from sympy.external.gmpy import lcm
from sympy.functions import (sqrt, exp, log, sin, cos, asin, atan,
sinh, cosh, asinh, acosh, atanh, acoth)
from sympy.functions import factorial, RisingFactorial
from sympy.functions.elementary.complexes import Abs, re, unpolarify
from sympy.functions.elementary.exponential import exp_polar
from sympy.functions.elementary.integers import ceiling
from sympy.functions.elementary.piecewise import Piecewise
from sympy.logic.boolalg import (And, Or)
from sympy import ordered
class TupleArg(Tuple):
# This method is only needed because hyper._eval_as_leading_term falls back
# (via super()) on using Function._eval_as_leading_term, which in turn
# calls as_leading_term on the args of the hyper. Ideally hyper should just
# have an _eval_as_leading_term method that handles all cases and this
# method should be removed because leading terms of tuples don't make
# sense.
def as_leading_term(self, *x, logx=None, cdir=0):
return TupleArg(*[f.as_leading_term(*x, logx=logx, cdir=cdir) for f in self.args])
def limit(self, x, xlim, dir='+'):
""" Compute limit x->xlim.
"""
from sympy.series.limits import limit
return TupleArg(*[limit(f, x, xlim, dir) for f in self.args])
# TODO should __new__ accept **options?
# TODO should constructors should check if parameters are sensible?
def _prep_tuple(v):
"""
Turn an iterable argument *v* into a tuple and unpolarify, since both
hypergeometric and meijer g-functions are unbranched in their parameters.
Examples
========
>>> from sympy.functions.special.hyper import _prep_tuple
>>> _prep_tuple([1, 2, 3])
(1, 2, 3)
>>> _prep_tuple((4, 5))
(4, 5)
>>> _prep_tuple((7, 8, 9))
(7, 8, 9)
"""
return TupleArg(*[unpolarify(x) for x in v])
class TupleParametersBase(Function):
""" Base class that takes care of differentiation, when some of
the arguments are actually tuples. """
# This is not deduced automatically since there are Tuples as arguments.
is_commutative = True
def _eval_derivative(self, s):
try:
res = 0
if self.args[0].has(s) or self.args[1].has(s):
for i, p in enumerate(self._diffargs):
m = self._diffargs[i].diff(s)
if m != 0:
res += self.fdiff((1, i))*m
return res + self.fdiff(3)*self.args[2].diff(s)
except (ArgumentIndexError, NotImplementedError):
return Derivative(self, s)
class hyper(TupleParametersBase):
r"""
The generalized hypergeometric function is defined by a series where
the ratios of successive terms are a rational function of the summation
index. When convergent, it is continued analytically to the largest
possible domain.
Explanation
===========
The hypergeometric function depends on two vectors of parameters, called
the numerator parameters $a_p$, and the denominator parameters
$b_q$. It also has an argument $z$. The series definition is
.. math ::
{}_pF_q\left(\begin{matrix} a_1, \cdots, a_p \\ b_1, \cdots, b_q \end{matrix}
\middle| z \right)
= \sum_{n=0}^\infty \frac{(a_1)_n \cdots (a_p)_n}{(b_1)_n \cdots (b_q)_n}
\frac{z^n}{n!},
where $(a)_n = (a)(a+1)\cdots(a+n-1)$ denotes the rising factorial.
If one of the $b_q$ is a non-positive integer then the series is
undefined unless one of the $a_p$ is a larger (i.e., smaller in
magnitude) non-positive integer. If none of the $b_q$ is a
non-positive integer and one of the $a_p$ is a non-positive
integer, then the series reduces to a polynomial. To simplify the
following discussion, we assume that none of the $a_p$ or
$b_q$ is a non-positive integer. For more details, see the
references.
The series converges for all $z$ if $p \le q$, and thus
defines an entire single-valued function in this case. If $p =
q+1$ the series converges for $|z| < 1$, and can be continued
analytically into a half-plane. If $p > q+1$ the series is
divergent for all $z$.
Please note the hypergeometric function constructor currently does *not*
check if the parameters actually yield a well-defined function.
Examples
========
The parameters $a_p$ and $b_q$ can be passed as arbitrary
iterables, for example:
>>> from sympy import hyper
>>> from sympy.abc import x, n, a
>>> h = hyper((1, 2, 3), [3, 4], x); h
hyper((1, 2), (4,), x)
>>> hyper((3, 1, 2), [3, 4], x, evaluate=False) # don't remove duplicates
hyper((1, 2, 3), (3, 4), x)
There is also pretty printing (it looks better using Unicode):
>>> from sympy import pprint
>>> pprint(h, use_unicode=False)
_
|_ /1, 2 | \
| | | x|
2 1 \ 4 | /
The parameters must always be iterables, even if they are vectors of
length one or zero:
>>> hyper((1, ), [], x)
hyper((1,), (), x)
But of course they may be variables (but if they depend on $x$ then you
should not expect much implemented functionality):
>>> hyper((n, a), (n**2,), x)
hyper((a, n), (n**2,), x)
The hypergeometric function generalizes many named special functions.
The function ``hyperexpand()`` tries to express a hypergeometric function
using named special functions. For example:
>>> from sympy import hyperexpand
>>> hyperexpand(hyper([], [], x))
exp(x)
You can also use ``expand_func()``:
>>> from sympy import expand_func
>>> expand_func(x*hyper([1, 1], [2], -x))
log(x + 1)
More examples:
>>> from sympy import S
>>> hyperexpand(hyper([], [S(1)/2], -x**2/4))
cos(x)
>>> hyperexpand(x*hyper([S(1)/2, S(1)/2], [S(3)/2], x**2))
asin(x)
We can also sometimes ``hyperexpand()`` parametric functions:
>>> from sympy.abc import a
>>> hyperexpand(hyper([-a], [], x))
(1 - x)**a
See Also
========
sympy.simplify.hyperexpand
gamma
meijerg
References
==========
.. [1] Luke, Y. L. (1969), The Special Functions and Their Approximations,
Volume 1
.. [2] https://en.wikipedia.org/wiki/Generalized_hypergeometric_function
"""
def __new__(cls, ap, bq, z, **kwargs):
# TODO should we check convergence conditions?
if kwargs.pop('evaluate', global_parameters.evaluate):
ca = Counter(Tuple(*ap))
cb = Counter(Tuple(*bq))
common = ca & cb
arg = ap, bq = [], []
for i, c in enumerate((ca, cb)):
c -= common
for k in ordered(c):
arg[i].extend([k]*c[k])
else:
ap = list(ordered(ap))
bq = list(ordered(bq))
return Function.__new__(cls, _prep_tuple(ap), _prep_tuple(bq), z, **kwargs)
@classmethod
def eval(cls, ap, bq, z):
if len(ap) <= len(bq) or (len(ap) == len(bq) + 1 and (Abs(z) <= 1) == True):
nz = unpolarify(z)
if z != nz:
return hyper(ap, bq, nz)
def fdiff(self, argindex=3):
if argindex != 3:
raise ArgumentIndexError(self, argindex)
nap = Tuple(*[a + 1 for a in self.ap])
nbq = Tuple(*[b + 1 for b in self.bq])
fac = Mul(*self.ap)/Mul(*self.bq)
return fac*hyper(nap, nbq, self.argument)
def _eval_expand_func(self, **hints):
from sympy.functions.special.gamma_functions import gamma
from sympy.simplify.hyperexpand import hyperexpand
if len(self.ap) == 2 and len(self.bq) == 1 and self.argument == 1:
a, b = self.ap
c = self.bq[0]
return gamma(c)*gamma(c - a - b)/gamma(c - a)/gamma(c - b)
return hyperexpand(self)
def _eval_rewrite_as_Sum(self, ap, bq, z, **kwargs):
from sympy.concrete.summations import Sum
n = Dummy("n", integer=True)
rfap = [RisingFactorial(a, n) for a in ap]
rfbq = [RisingFactorial(b, n) for b in bq]
coeff = Mul(*rfap) / Mul(*rfbq)
return Piecewise((Sum(coeff * z**n / factorial(n), (n, 0, oo)),
self.convergence_statement), (self, True))
def _eval_as_leading_term(self, x, logx=None, cdir=0):
arg = self.args[2]
x0 = arg.subs(x, 0)
if x0 is S.NaN:
x0 = arg.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
if x0 is S.Zero:
return S.One
return super()._eval_as_leading_term(x, logx=logx, cdir=cdir)
def _eval_nseries(self, x, n, logx, cdir=0):
from sympy.series.order import Order
arg = self.args[2]
x0 = arg.limit(x, 0)
ap = self.args[0]
bq = self.args[1]
if not (arg == x and x0 == 0):
# It would be better to do something with arg.nseries here, rather
# than falling back on Function._eval_nseries. The code below
# though is not sufficient if arg is something like x/(x+1).
from sympy.simplify.hyperexpand import hyperexpand
return hyperexpand(super()._eval_nseries(x, n, logx))
terms = []
for i in range(n):
num = Mul(*[RisingFactorial(a, i) for a in ap])
den = Mul(*[RisingFactorial(b, i) for b in bq])
terms.append(((num/den) * (arg**i)) / factorial(i))
return (Add(*terms) + Order(x**n,x))
@property
def argument(self):
""" Argument of the hypergeometric function. """
return self.args[2]
@property
def ap(self):
""" Numerator parameters of the hypergeometric function. """
return Tuple(*self.args[0])
@property
def bq(self):
""" Denominator parameters of the hypergeometric function. """
return Tuple(*self.args[1])
@property
def _diffargs(self):
return self.ap + self.bq
@property
def eta(self):
""" A quantity related to the convergence of the series. """
return sum(self.ap) - sum(self.bq)
@property
def radius_of_convergence(self):
"""
Compute the radius of convergence of the defining series.
Explanation
===========
Note that even if this is not ``oo``, the function may still be
evaluated outside of the radius of convergence by analytic
continuation. But if this is zero, then the function is not actually
defined anywhere else.
Examples
========
>>> from sympy import hyper
>>> from sympy.abc import z
>>> hyper((1, 2), [3], z).radius_of_convergence
1
>>> hyper((1, 2, 3), [4], z).radius_of_convergence
0
>>> hyper((1, 2), (3, 4), z).radius_of_convergence
oo
"""
if any(a.is_integer and (a <= 0) == True for a in self.ap + self.bq):
aints = [a for a in self.ap if a.is_Integer and (a <= 0) == True]
bints = [a for a in self.bq if a.is_Integer and (a <= 0) == True]
if len(aints) < len(bints):
return S.Zero
popped = False
for b in bints:
cancelled = False
while aints:
a = aints.pop()
if a >= b:
cancelled = True
break
popped = True
if not cancelled:
return S.Zero
if aints or popped:
# There are still non-positive numerator parameters.
# This is a polynomial.
return oo
if len(self.ap) == len(self.bq) + 1:
return S.One
elif len(self.ap) <= len(self.bq):
return oo
else:
return S.Zero
@property
def convergence_statement(self):
""" Return a condition on z under which the series converges. """
R = self.radius_of_convergence
if R == 0:
return False
if R == oo:
return True
# The special functions and their approximations, page 44
e = self.eta
z = self.argument
c1 = And(re(e) < 0, abs(z) <= 1)
c2 = And(0 <= re(e), re(e) < 1, abs(z) <= 1, Ne(z, 1))
c3 = And(re(e) >= 1, abs(z) < 1)
return Or(c1, c2, c3)
def _eval_simplify(self, **kwargs):
from sympy.simplify.hyperexpand import hyperexpand
return hyperexpand(self)
class meijerg(TupleParametersBase):
r"""
The Meijer G-function is defined by a Mellin-Barnes type integral that
resembles an inverse Mellin transform. It generalizes the hypergeometric
functions.
Explanation
===========
The Meijer G-function depends on four sets of parameters. There are
"*numerator parameters*"
$a_1, \ldots, a_n$ and $a_{n+1}, \ldots, a_p$, and there are
"*denominator parameters*"
$b_1, \ldots, b_m$ and $b_{m+1}, \ldots, b_q$.
Confusingly, it is traditionally denoted as follows (note the position
of $m$, $n$, $p$, $q$, and how they relate to the lengths of the four
parameter vectors):
.. math ::
G_{p,q}^{m,n} \left(\begin{matrix}a_1, \cdots, a_n & a_{n+1}, \cdots, a_p \\
b_1, \cdots, b_m & b_{m+1}, \cdots, b_q
\end{matrix} \middle| z \right).
However, in SymPy the four parameter vectors are always available
separately (see examples), so that there is no need to keep track of the
decorating sub- and super-scripts on the G symbol.
The G function is defined as the following integral:
.. math ::
\frac{1}{2 \pi i} \int_L \frac{\prod_{j=1}^m \Gamma(b_j - s)
\prod_{j=1}^n \Gamma(1 - a_j + s)}{\prod_{j=m+1}^q \Gamma(1- b_j +s)
\prod_{j=n+1}^p \Gamma(a_j - s)} z^s \mathrm{d}s,
where $\Gamma(z)$ is the gamma function. There are three possible
contours which we will not describe in detail here (see the references).
If the integral converges along more than one of them, the definitions
agree. The contours all separate the poles of $\Gamma(1-a_j+s)$
from the poles of $\Gamma(b_k-s)$, so in particular the G function
is undefined if $a_j - b_k \in \mathbb{Z}_{>0}$ for some
$j \le n$ and $k \le m$.
The conditions under which one of the contours yields a convergent integral
are complicated and we do not state them here, see the references.
Please note currently the Meijer G-function constructor does *not* check any
convergence conditions.
Examples
========
You can pass the parameters either as four separate vectors:
>>> from sympy import meijerg, Tuple, pprint
>>> from sympy.abc import x, a
>>> pprint(meijerg((1, 2), (a, 4), (5,), [], x), use_unicode=False)
__1, 2 /1, 2 4, a | \
/__ | | x|
\_|4, 1 \ 5 | /
Or as two nested vectors:
>>> pprint(meijerg([(1, 2), (3, 4)], ([5], Tuple()), x), use_unicode=False)
__1, 2 /1, 2 3, 4 | \
/__ | | x|
\_|4, 1 \ 5 | /
As with the hypergeometric function, the parameters may be passed as
arbitrary iterables. Vectors of length zero and one also have to be
passed as iterables. The parameters need not be constants, but if they
depend on the argument then not much implemented functionality should be
expected.
All the subvectors of parameters are available:
>>> from sympy import pprint
>>> g = meijerg([1], [2], [3], [4], x)
>>> pprint(g, use_unicode=False)
__1, 1 /1 2 | \
/__ | | x|
\_|2, 2 \3 4 | /
>>> g.an
(1,)
>>> g.ap
(1, 2)
>>> g.aother
(2,)
>>> g.bm
(3,)
>>> g.bq
(3, 4)
>>> g.bother
(4,)
The Meijer G-function generalizes the hypergeometric functions.
In some cases it can be expressed in terms of hypergeometric functions,
using Slater's theorem. For example:
>>> from sympy import hyperexpand
>>> from sympy.abc import a, b, c
>>> hyperexpand(meijerg([a], [], [c], [b], x), allow_hyper=True)
x**c*gamma(-a + c + 1)*hyper((-a + c + 1,),
(-b + c + 1,), -x)/gamma(-b + c + 1)
Thus the Meijer G-function also subsumes many named functions as special
cases. You can use ``expand_func()`` or ``hyperexpand()`` to (try to)
rewrite a Meijer G-function in terms of named special functions. For
example:
>>> from sympy import expand_func, S
>>> expand_func(meijerg([[],[]], [[0],[]], -x))
exp(x)
>>> hyperexpand(meijerg([[],[]], [[S(1)/2],[0]], (x/2)**2))
sin(x)/sqrt(pi)
See Also
========
hyper
sympy.simplify.hyperexpand
References
==========
.. [1] Luke, Y. L. (1969), The Special Functions and Their Approximations,
Volume 1
.. [2] https://en.wikipedia.org/wiki/Meijer_G-function
"""
def __new__(cls, *args, **kwargs):
if len(args) == 5:
args = [(args[0], args[1]), (args[2], args[3]), args[4]]
if len(args) != 3:
raise TypeError("args must be either as, as', bs, bs', z or "
"as, bs, z")
def tr(p):
if len(p) != 2:
raise TypeError("wrong argument")
p = [list(ordered(i)) for i in p]
return TupleArg(_prep_tuple(p[0]), _prep_tuple(p[1]))
arg0, arg1 = tr(args[0]), tr(args[1])
if Tuple(arg0, arg1).has(oo, zoo, -oo):
raise ValueError("G-function parameters must be finite")
if any((a - b).is_Integer and a - b > 0
for a in arg0[0] for b in arg1[0]):
raise ValueError("no parameter a1, ..., an may differ from "
"any b1, ..., bm by a positive integer")
# TODO should we check convergence conditions?
return Function.__new__(cls, arg0, arg1, args[2], **kwargs)
def fdiff(self, argindex=3):
if argindex != 3:
return self._diff_wrt_parameter(argindex[1])
if len(self.an) >= 1:
a = list(self.an)
a[0] -= 1
G = meijerg(a, self.aother, self.bm, self.bother, self.argument)
return 1/self.argument * ((self.an[0] - 1)*self + G)
elif len(self.bm) >= 1:
b = list(self.bm)
b[0] += 1
G = meijerg(self.an, self.aother, b, self.bother, self.argument)
return 1/self.argument * (self.bm[0]*self - G)
else:
return S.Zero
def _diff_wrt_parameter(self, idx):
# Differentiation wrt a parameter can only be done in very special
# cases. In particular, if we want to differentiate with respect to
# `a`, all other gamma factors have to reduce to rational functions.
#
# Let MT denote mellin transform. Suppose T(-s) is the gamma factor
# appearing in the definition of G. Then
#
# MT(log(z)G(z)) = d/ds T(s) = d/da T(s) + ...
#
# Thus d/da G(z) = log(z)G(z) - ...
# The ... can be evaluated as a G function under the above conditions,
# the formula being most easily derived by using
#
# d Gamma(s + n) Gamma(s + n) / 1 1 1 \
# -- ------------ = ------------ | - + ---- + ... + --------- |
# ds Gamma(s) Gamma(s) \ s s + 1 s + n - 1 /
#
# which follows from the difference equation of the digamma function.
# (There is a similar equation for -n instead of +n).
# We first figure out how to pair the parameters.
an = list(self.an)
ap = list(self.aother)
bm = list(self.bm)
bq = list(self.bother)
if idx < len(an):
an.pop(idx)
else:
idx -= len(an)
if idx < len(ap):
ap.pop(idx)
else:
idx -= len(ap)
if idx < len(bm):
bm.pop(idx)
else:
bq.pop(idx - len(bm))
pairs1 = []
pairs2 = []
for l1, l2, pairs in [(an, bq, pairs1), (ap, bm, pairs2)]:
while l1:
x = l1.pop()
found = None
for i, y in enumerate(l2):
if not Mod((x - y).simplify(), 1):
found = i
break
if found is None:
raise NotImplementedError('Derivative not expressible '
'as G-function?')
y = l2[i]
l2.pop(i)
pairs.append((x, y))
# Now build the result.
res = log(self.argument)*self
for a, b in pairs1:
sign = 1
n = a - b
base = b
if n < 0:
sign = -1
n = b - a
base = a
for k in range(n):
res -= sign*meijerg(self.an + (base + k + 1,), self.aother,
self.bm, self.bother + (base + k + 0,),
self.argument)
for a, b in pairs2:
sign = 1
n = b - a
base = a
if n < 0:
sign = -1
n = a - b
base = b
for k in range(n):
res -= sign*meijerg(self.an, self.aother + (base + k + 1,),
self.bm + (base + k + 0,), self.bother,
self.argument)
return res
def get_period(self):
"""
Return a number $P$ such that $G(x*exp(I*P)) == G(x)$.
Examples
========
>>> from sympy import meijerg, pi, S
>>> from sympy.abc import z
>>> meijerg([1], [], [], [], z).get_period()
2*pi
>>> meijerg([pi], [], [], [], z).get_period()
oo
>>> meijerg([1, 2], [], [], [], z).get_period()
oo
>>> meijerg([1,1], [2], [1, S(1)/2, S(1)/3], [1], z).get_period()
12*pi
"""
# This follows from slater's theorem.
def compute(l):
# first check that no two differ by an integer
for i, b in enumerate(l):
if not b.is_Rational:
return oo
for j in range(i + 1, len(l)):
if not Mod((b - l[j]).simplify(), 1):
return oo
return lcm(*(x.q for x in l))
beta = compute(self.bm)
alpha = compute(self.an)
p, q = len(self.ap), len(self.bq)
if p == q:
if oo in (alpha, beta):
return oo
return 2*pi*lcm(alpha, beta)
elif p < q:
return 2*pi*beta
else:
return 2*pi*alpha
def _eval_expand_func(self, **hints):
from sympy.simplify.hyperexpand import hyperexpand
return hyperexpand(self)
def _eval_evalf(self, prec):
# The default code is insufficient for polar arguments.
# mpmath provides an optional argument "r", which evaluates
# G(z**(1/r)). I am not sure what its intended use is, but we hijack it
# here in the following way: to evaluate at a number z of |argument|
# less than (say) n*pi, we put r=1/n, compute z' = root(z, n)
# (carefully so as not to loose the branch information), and evaluate
# G(z'**(1/r)) = G(z'**n) = G(z).
import mpmath
znum = self.argument._eval_evalf(prec)
if znum.has(exp_polar):
znum, branch = znum.as_coeff_mul(exp_polar)
if len(branch) != 1:
return
branch = branch[0].args[0]/I
else:
branch = S.Zero
n = ceiling(abs(branch/pi)) + 1
znum = znum**(S.One/n)*exp(I*branch / n)
# Convert all args to mpf or mpc
try:
[z, r, ap, bq] = [arg._to_mpmath(prec)
for arg in [znum, 1/n, self.args[0], self.args[1]]]
except ValueError:
return
with mpmath.workprec(prec):
v = mpmath.meijerg(ap, bq, z, r)
return Expr._from_mpmath(v, prec)
def _eval_as_leading_term(self, x, logx=None, cdir=0):
from sympy.simplify.hyperexpand import hyperexpand
return hyperexpand(self).as_leading_term(x, logx=logx, cdir=cdir)
def integrand(self, s):
""" Get the defining integrand D(s). """
from sympy.functions.special.gamma_functions import gamma
return self.argument**s \
* Mul(*(gamma(b - s) for b in self.bm)) \
* Mul(*(gamma(1 - a + s) for a in self.an)) \
/ Mul(*(gamma(1 - b + s) for b in self.bother)) \
/ Mul(*(gamma(a - s) for a in self.aother))
@property
def argument(self):
""" Argument of the Meijer G-function. """
return self.args[2]
@property
def an(self):
""" First set of numerator parameters. """
return Tuple(*self.args[0][0])
@property
def ap(self):
""" Combined numerator parameters. """
return Tuple(*(self.args[0][0] + self.args[0][1]))
@property
def aother(self):
""" Second set of numerator parameters. """
return Tuple(*self.args[0][1])
@property
def bm(self):
""" First set of denominator parameters. """
return Tuple(*self.args[1][0])
@property
def bq(self):
""" Combined denominator parameters. """
return Tuple(*(self.args[1][0] + self.args[1][1]))
@property
def bother(self):
""" Second set of denominator parameters. """
return Tuple(*self.args[1][1])
@property
def _diffargs(self):
return self.ap + self.bq
@property
def nu(self):
""" A quantity related to the convergence region of the integral,
c.f. references. """
return sum(self.bq) - sum(self.ap)
@property
def delta(self):
""" A quantity related to the convergence region of the integral,
c.f. references. """
return len(self.bm) + len(self.an) - S(len(self.ap) + len(self.bq))/2
@property
def is_number(self):
""" Returns true if expression has numeric data only. """
return not self.free_symbols
class HyperRep(Function):
"""
A base class for "hyper representation functions".
This is used exclusively in ``hyperexpand()``, but fits more logically here.
pFq is branched at 1 if p == q+1. For use with slater-expansion, we want
define an "analytic continuation" to all polar numbers, which is
continuous on circles and on the ray t*exp_polar(I*pi). Moreover, we want
a "nice" expression for the various cases.
This base class contains the core logic, concrete derived classes only
supply the actual functions.
"""
@classmethod
def eval(cls, *args):
newargs = tuple(map(unpolarify, args[:-1])) + args[-1:]
if args != newargs:
return cls(*newargs)
@classmethod
def _expr_small(cls, x):
""" An expression for F(x) which holds for |x| < 1. """
raise NotImplementedError
@classmethod
def _expr_small_minus(cls, x):
""" An expression for F(-x) which holds for |x| < 1. """
raise NotImplementedError
@classmethod
def _expr_big(cls, x, n):
""" An expression for F(exp_polar(2*I*pi*n)*x), |x| > 1. """
raise NotImplementedError
@classmethod
def _expr_big_minus(cls, x, n):
""" An expression for F(exp_polar(2*I*pi*n + pi*I)*x), |x| > 1. """
raise NotImplementedError
def _eval_rewrite_as_nonrep(self, *args, **kwargs):
x, n = self.args[-1].extract_branch_factor(allow_half=True)
minus = False
newargs = self.args[:-1] + (x,)
if not n.is_Integer:
minus = True
n -= S.Half
newerargs = newargs + (n,)
if minus:
small = self._expr_small_minus(*newargs)
big = self._expr_big_minus(*newerargs)
else:
small = self._expr_small(*newargs)
big = self._expr_big(*newerargs)
if big == small:
return small
return Piecewise((big, abs(x) > 1), (small, True))
def _eval_rewrite_as_nonrepsmall(self, *args, **kwargs):
x, n = self.args[-1].extract_branch_factor(allow_half=True)
args = self.args[:-1] + (x,)
if not n.is_Integer:
return self._expr_small_minus(*args)
return self._expr_small(*args)
class HyperRep_power1(HyperRep):
""" Return a representative for hyper([-a], [], z) == (1 - z)**a. """
@classmethod
def _expr_small(cls, a, x):
return (1 - x)**a
@classmethod
def _expr_small_minus(cls, a, x):
return (1 + x)**a
@classmethod
def _expr_big(cls, a, x, n):
if a.is_integer:
return cls._expr_small(a, x)
return (x - 1)**a*exp((2*n - 1)*pi*I*a)
@classmethod
def _expr_big_minus(cls, a, x, n):
if a.is_integer:
return cls._expr_small_minus(a, x)
return (1 + x)**a*exp(2*n*pi*I*a)
class HyperRep_power2(HyperRep):
""" Return a representative for hyper([a, a - 1/2], [2*a], z). """
@classmethod
def _expr_small(cls, a, x):
return 2**(2*a - 1)*(1 + sqrt(1 - x))**(1 - 2*a)
@classmethod
def _expr_small_minus(cls, a, x):
return 2**(2*a - 1)*(1 + sqrt(1 + x))**(1 - 2*a)
@classmethod
def _expr_big(cls, a, x, n):
sgn = -1
if n.is_odd:
sgn = 1
n -= 1
return 2**(2*a - 1)*(1 + sgn*I*sqrt(x - 1))**(1 - 2*a) \
*exp(-2*n*pi*I*a)
@classmethod
def _expr_big_minus(cls, a, x, n):
sgn = 1
if n.is_odd:
sgn = -1
return sgn*2**(2*a - 1)*(sqrt(1 + x) + sgn)**(1 - 2*a)*exp(-2*pi*I*a*n)
class HyperRep_log1(HyperRep):
""" Represent -z*hyper([1, 1], [2], z) == log(1 - z). """
@classmethod
def _expr_small(cls, x):
return log(1 - x)
@classmethod
def _expr_small_minus(cls, x):
return log(1 + x)
@classmethod
def _expr_big(cls, x, n):
return log(x - 1) + (2*n - 1)*pi*I
@classmethod
def _expr_big_minus(cls, x, n):
return log(1 + x) + 2*n*pi*I
class HyperRep_atanh(HyperRep):
""" Represent hyper([1/2, 1], [3/2], z) == atanh(sqrt(z))/sqrt(z). """
@classmethod
def _expr_small(cls, x):
return atanh(sqrt(x))/sqrt(x)
def _expr_small_minus(cls, x):
return atan(sqrt(x))/sqrt(x)
def _expr_big(cls, x, n):
if n.is_even:
return (acoth(sqrt(x)) + I*pi/2)/sqrt(x)
else:
return (acoth(sqrt(x)) - I*pi/2)/sqrt(x)
def _expr_big_minus(cls, x, n):
if n.is_even:
return atan(sqrt(x))/sqrt(x)
else:
return (atan(sqrt(x)) - pi)/sqrt(x)
class HyperRep_asin1(HyperRep):
""" Represent hyper([1/2, 1/2], [3/2], z) == asin(sqrt(z))/sqrt(z). """
@classmethod
def _expr_small(cls, z):
return asin(sqrt(z))/sqrt(z)
@classmethod
def _expr_small_minus(cls, z):
return asinh(sqrt(z))/sqrt(z)
@classmethod
def _expr_big(cls, z, n):
return S.NegativeOne**n*((S.Half - n)*pi/sqrt(z) + I*acosh(sqrt(z))/sqrt(z))
@classmethod
def _expr_big_minus(cls, z, n):
return S.NegativeOne**n*(asinh(sqrt(z))/sqrt(z) + n*pi*I/sqrt(z))
class HyperRep_asin2(HyperRep):
""" Represent hyper([1, 1], [3/2], z) == asin(sqrt(z))/sqrt(z)/sqrt(1-z). """
# TODO this can be nicer
@classmethod
def _expr_small(cls, z):
return HyperRep_asin1._expr_small(z) \
/HyperRep_power1._expr_small(S.Half, z)
@classmethod
def _expr_small_minus(cls, z):
return HyperRep_asin1._expr_small_minus(z) \
/HyperRep_power1._expr_small_minus(S.Half, z)
@classmethod
def _expr_big(cls, z, n):
return HyperRep_asin1._expr_big(z, n) \
/HyperRep_power1._expr_big(S.Half, z, n)
@classmethod
def _expr_big_minus(cls, z, n):
return HyperRep_asin1._expr_big_minus(z, n) \
/HyperRep_power1._expr_big_minus(S.Half, z, n)
class HyperRep_sqrts1(HyperRep):
""" Return a representative for hyper([-a, 1/2 - a], [1/2], z). """
@classmethod
def _expr_small(cls, a, z):
return ((1 - sqrt(z))**(2*a) + (1 + sqrt(z))**(2*a))/2
@classmethod
def _expr_small_minus(cls, a, z):
return (1 + z)**a*cos(2*a*atan(sqrt(z)))
@classmethod
def _expr_big(cls, a, z, n):
if n.is_even:
return ((sqrt(z) + 1)**(2*a)*exp(2*pi*I*n*a) +
(sqrt(z) - 1)**(2*a)*exp(2*pi*I*(n - 1)*a))/2
else:
n -= 1
return ((sqrt(z) - 1)**(2*a)*exp(2*pi*I*a*(n + 1)) +
(sqrt(z) + 1)**(2*a)*exp(2*pi*I*a*n))/2
@classmethod
def _expr_big_minus(cls, a, z, n):
if n.is_even:
return (1 + z)**a*exp(2*pi*I*n*a)*cos(2*a*atan(sqrt(z)))
else:
return (1 + z)**a*exp(2*pi*I*n*a)*cos(2*a*atan(sqrt(z)) - 2*pi*a)
class HyperRep_sqrts2(HyperRep):
""" Return a representative for
sqrt(z)/2*[(1-sqrt(z))**2a - (1 + sqrt(z))**2a]
== -2*z/(2*a+1) d/dz hyper([-a - 1/2, -a], [1/2], z)"""
@classmethod
def _expr_small(cls, a, z):
return sqrt(z)*((1 - sqrt(z))**(2*a) - (1 + sqrt(z))**(2*a))/2
@classmethod
def _expr_small_minus(cls, a, z):
return sqrt(z)*(1 + z)**a*sin(2*a*atan(sqrt(z)))
@classmethod
def _expr_big(cls, a, z, n):
if n.is_even:
return sqrt(z)/2*((sqrt(z) - 1)**(2*a)*exp(2*pi*I*a*(n - 1)) -
(sqrt(z) + 1)**(2*a)*exp(2*pi*I*a*n))
else:
n -= 1
return sqrt(z)/2*((sqrt(z) - 1)**(2*a)*exp(2*pi*I*a*(n + 1)) -
(sqrt(z) + 1)**(2*a)*exp(2*pi*I*a*n))
def _expr_big_minus(cls, a, z, n):
if n.is_even:
return (1 + z)**a*exp(2*pi*I*n*a)*sqrt(z)*sin(2*a*atan(sqrt(z)))
else:
return (1 + z)**a*exp(2*pi*I*n*a)*sqrt(z) \
*sin(2*a*atan(sqrt(z)) - 2*pi*a)
class HyperRep_log2(HyperRep):
""" Represent log(1/2 + sqrt(1 - z)/2) == -z/4*hyper([3/2, 1, 1], [2, 2], z) """
@classmethod
def _expr_small(cls, z):
return log(S.Half + sqrt(1 - z)/2)
@classmethod
def _expr_small_minus(cls, z):
return log(S.Half + sqrt(1 + z)/2)
@classmethod
def _expr_big(cls, z, n):
if n.is_even:
return (n - S.Half)*pi*I + log(sqrt(z)/2) + I*asin(1/sqrt(z))
else:
return (n - S.Half)*pi*I + log(sqrt(z)/2) - I*asin(1/sqrt(z))
def _expr_big_minus(cls, z, n):
if n.is_even:
return pi*I*n + log(S.Half + sqrt(1 + z)/2)
else:
return pi*I*n + log(sqrt(1 + z)/2 - S.Half)
class HyperRep_cosasin(HyperRep):
""" Represent hyper([a, -a], [1/2], z) == cos(2*a*asin(sqrt(z))). """
# Note there are many alternative expressions, e.g. as powers of a sum of
# square roots.
@classmethod
def _expr_small(cls, a, z):
return cos(2*a*asin(sqrt(z)))
@classmethod
def _expr_small_minus(cls, a, z):
return cosh(2*a*asinh(sqrt(z)))
@classmethod
def _expr_big(cls, a, z, n):
return cosh(2*a*acosh(sqrt(z)) + a*pi*I*(2*n - 1))
@classmethod
def _expr_big_minus(cls, a, z, n):
return cosh(2*a*asinh(sqrt(z)) + 2*a*pi*I*n)
class HyperRep_sinasin(HyperRep):
""" Represent 2*a*z*hyper([1 - a, 1 + a], [3/2], z)
== sqrt(z)/sqrt(1-z)*sin(2*a*asin(sqrt(z))) """
@classmethod
def _expr_small(cls, a, z):
return sqrt(z)/sqrt(1 - z)*sin(2*a*asin(sqrt(z)))
@classmethod
def _expr_small_minus(cls, a, z):
return -sqrt(z)/sqrt(1 + z)*sinh(2*a*asinh(sqrt(z)))
@classmethod
def _expr_big(cls, a, z, n):
return -1/sqrt(1 - 1/z)*sinh(2*a*acosh(sqrt(z)) + a*pi*I*(2*n - 1))
@classmethod
def _expr_big_minus(cls, a, z, n):
return -1/sqrt(1 + 1/z)*sinh(2*a*asinh(sqrt(z)) + 2*a*pi*I*n)
class appellf1(Function):
r"""
This is the Appell hypergeometric function of two variables as:
.. math ::
F_1(a,b_1,b_2,c,x,y) = \sum_{m=0}^{\infty} \sum_{n=0}^{\infty}
\frac{(a)_{m+n} (b_1)_m (b_2)_n}{(c)_{m+n}}
\frac{x^m y^n}{m! n!}.
Examples
========
>>> from sympy import appellf1, symbols
>>> x, y, a, b1, b2, c = symbols('x y a b1 b2 c')
>>> appellf1(2., 1., 6., 4., 5., 6.)
0.0063339426292673
>>> appellf1(12., 12., 6., 4., 0.5, 0.12)
172870711.659936
>>> appellf1(40, 2, 6, 4, 15, 60)
appellf1(40, 2, 6, 4, 15, 60)
>>> appellf1(20., 12., 10., 3., 0.5, 0.12)
15605338197184.4
>>> appellf1(40, 2, 6, 4, x, y)
appellf1(40, 2, 6, 4, x, y)
>>> appellf1(a, b1, b2, c, x, y)
appellf1(a, b1, b2, c, x, y)
References
==========
.. [1] https://en.wikipedia.org/wiki/Appell_series
.. [2] https://functions.wolfram.com/HypergeometricFunctions/AppellF1/
"""
@classmethod
def eval(cls, a, b1, b2, c, x, y):
if default_sort_key(b1) > default_sort_key(b2):
b1, b2 = b2, b1
x, y = y, x
return cls(a, b1, b2, c, x, y)
elif b1 == b2 and default_sort_key(x) > default_sort_key(y):
x, y = y, x
return cls(a, b1, b2, c, x, y)
if x == 0 and y == 0:
return S.One
def fdiff(self, argindex=5):
a, b1, b2, c, x, y = self.args
if argindex == 5:
return (a*b1/c)*appellf1(a + 1, b1 + 1, b2, c + 1, x, y)
elif argindex == 6:
return (a*b2/c)*appellf1(a + 1, b1, b2 + 1, c + 1, x, y)
elif argindex in (1, 2, 3, 4):
return Derivative(self, self.args[argindex-1])
else:
raise ArgumentIndexError(self, argindex)
PK ]ZZZ�}1�� � , sympy/functions/special/mathieu_functions.py""" This module contains the Mathieu functions.
"""
from sympy.core.function import Function, ArgumentIndexError
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.elementary.trigonometric import sin, cos
class MathieuBase(Function):
"""
Abstract base class for Mathieu functions.
This class is meant to reduce code duplication.
"""
unbranched = True
def _eval_conjugate(self):
a, q, z = self.args
return self.func(a.conjugate(), q.conjugate(), z.conjugate())
class mathieus(MathieuBase):
r"""
The Mathieu Sine function $S(a,q,z)$.
Explanation
===========
This function is one solution of the Mathieu differential equation:
.. math ::
y(x)^{\prime\prime} + (a - 2 q \cos(2 x)) y(x) = 0
The other solution is the Mathieu Cosine function.
Examples
========
>>> from sympy import diff, mathieus
>>> from sympy.abc import a, q, z
>>> mathieus(a, q, z)
mathieus(a, q, z)
>>> mathieus(a, 0, z)
sin(sqrt(a)*z)
>>> diff(mathieus(a, q, z), z)
mathieusprime(a, q, z)
See Also
========
mathieuc: Mathieu cosine function.
mathieusprime: Derivative of Mathieu sine function.
mathieucprime: Derivative of Mathieu cosine function.
References
==========
.. [1] https://en.wikipedia.org/wiki/Mathieu_function
.. [2] https://dlmf.nist.gov/28
.. [3] https://mathworld.wolfram.com/MathieuFunction.html
.. [4] https://functions.wolfram.com/MathieuandSpheroidalFunctions/MathieuS/
"""
def fdiff(self, argindex=1):
if argindex == 3:
a, q, z = self.args
return mathieusprime(a, q, z)
else:
raise ArgumentIndexError(self, argindex)
@classmethod
def eval(cls, a, q, z):
if q.is_Number and q.is_zero:
return sin(sqrt(a)*z)
# Try to pull out factors of -1
if z.could_extract_minus_sign():
return -cls(a, q, -z)
class mathieuc(MathieuBase):
r"""
The Mathieu Cosine function $C(a,q,z)$.
Explanation
===========
This function is one solution of the Mathieu differential equation:
.. math ::
y(x)^{\prime\prime} + (a - 2 q \cos(2 x)) y(x) = 0
The other solution is the Mathieu Sine function.
Examples
========
>>> from sympy import diff, mathieuc
>>> from sympy.abc import a, q, z
>>> mathieuc(a, q, z)
mathieuc(a, q, z)
>>> mathieuc(a, 0, z)
cos(sqrt(a)*z)
>>> diff(mathieuc(a, q, z), z)
mathieucprime(a, q, z)
See Also
========
mathieus: Mathieu sine function
mathieusprime: Derivative of Mathieu sine function
mathieucprime: Derivative of Mathieu cosine function
References
==========
.. [1] https://en.wikipedia.org/wiki/Mathieu_function
.. [2] https://dlmf.nist.gov/28
.. [3] https://mathworld.wolfram.com/MathieuFunction.html
.. [4] https://functions.wolfram.com/MathieuandSpheroidalFunctions/MathieuC/
"""
def fdiff(self, argindex=1):
if argindex == 3:
a, q, z = self.args
return mathieucprime(a, q, z)
else:
raise ArgumentIndexError(self, argindex)
@classmethod
def eval(cls, a, q, z):
if q.is_Number and q.is_zero:
return cos(sqrt(a)*z)
# Try to pull out factors of -1
if z.could_extract_minus_sign():
return cls(a, q, -z)
class mathieusprime(MathieuBase):
r"""
The derivative $S^{\prime}(a,q,z)$ of the Mathieu Sine function.
Explanation
===========
This function is one solution of the Mathieu differential equation:
.. math ::
y(x)^{\prime\prime} + (a - 2 q \cos(2 x)) y(x) = 0
The other solution is the Mathieu Cosine function.
Examples
========
>>> from sympy import diff, mathieusprime
>>> from sympy.abc import a, q, z
>>> mathieusprime(a, q, z)
mathieusprime(a, q, z)
>>> mathieusprime(a, 0, z)
sqrt(a)*cos(sqrt(a)*z)
>>> diff(mathieusprime(a, q, z), z)
(-a + 2*q*cos(2*z))*mathieus(a, q, z)
See Also
========
mathieus: Mathieu sine function
mathieuc: Mathieu cosine function
mathieucprime: Derivative of Mathieu cosine function
References
==========
.. [1] https://en.wikipedia.org/wiki/Mathieu_function
.. [2] https://dlmf.nist.gov/28
.. [3] https://mathworld.wolfram.com/MathieuFunction.html
.. [4] https://functions.wolfram.com/MathieuandSpheroidalFunctions/MathieuSPrime/
"""
def fdiff(self, argindex=1):
if argindex == 3:
a, q, z = self.args
return (2*q*cos(2*z) - a)*mathieus(a, q, z)
else:
raise ArgumentIndexError(self, argindex)
@classmethod
def eval(cls, a, q, z):
if q.is_Number and q.is_zero:
return sqrt(a)*cos(sqrt(a)*z)
# Try to pull out factors of -1
if z.could_extract_minus_sign():
return cls(a, q, -z)
class mathieucprime(MathieuBase):
r"""
The derivative $C^{\prime}(a,q,z)$ of the Mathieu Cosine function.
Explanation
===========
This function is one solution of the Mathieu differential equation:
.. math ::
y(x)^{\prime\prime} + (a - 2 q \cos(2 x)) y(x) = 0
The other solution is the Mathieu Sine function.
Examples
========
>>> from sympy import diff, mathieucprime
>>> from sympy.abc import a, q, z
>>> mathieucprime(a, q, z)
mathieucprime(a, q, z)
>>> mathieucprime(a, 0, z)
-sqrt(a)*sin(sqrt(a)*z)
>>> diff(mathieucprime(a, q, z), z)
(-a + 2*q*cos(2*z))*mathieuc(a, q, z)
See Also
========
mathieus: Mathieu sine function
mathieuc: Mathieu cosine function
mathieusprime: Derivative of Mathieu sine function
References
==========
.. [1] https://en.wikipedia.org/wiki/Mathieu_function
.. [2] https://dlmf.nist.gov/28
.. [3] https://mathworld.wolfram.com/MathieuFunction.html
.. [4] https://functions.wolfram.com/MathieuandSpheroidalFunctions/MathieuCPrime/
"""
def fdiff(self, argindex=1):
if argindex == 3:
a, q, z = self.args
return (2*q*cos(2*z) - a)*mathieuc(a, q, z)
else:
raise ArgumentIndexError(self, argindex)
@classmethod
def eval(cls, a, q, z):
if q.is_Number and q.is_zero:
return -sqrt(a)*sin(sqrt(a)*z)
# Try to pull out factors of -1
if z.could_extract_minus_sign():
return -cls(a, q, -z)
PK ]ZZZ��,~� ~� & sympy/functions/special/polynomials.py"""
This module mainly implements special orthogonal polynomials.
See also functions.combinatorial.numbers which contains some
combinatorial polynomials.
"""
from sympy.core import Rational
from sympy.core.function import Function, ArgumentIndexError
from sympy.core.singleton import S
from sympy.core.symbol import Dummy
from sympy.functions.combinatorial.factorials import binomial, factorial, RisingFactorial
from sympy.functions.elementary.complexes import re
from sympy.functions.elementary.exponential import exp
from sympy.functions.elementary.integers import floor
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.elementary.trigonometric import cos, sec
from sympy.functions.special.gamma_functions import gamma
from sympy.functions.special.hyper import hyper
from sympy.polys.orthopolys import (chebyshevt_poly, chebyshevu_poly,
gegenbauer_poly, hermite_poly, hermite_prob_poly,
jacobi_poly, laguerre_poly, legendre_poly)
_x = Dummy('x')
class OrthogonalPolynomial(Function):
"""Base class for orthogonal polynomials.
"""
@classmethod
def _eval_at_order(cls, n, x):
if n.is_integer and n >= 0:
return cls._ortho_poly(int(n), _x).subs(_x, x)
def _eval_conjugate(self):
return self.func(self.args[0], self.args[1].conjugate())
#----------------------------------------------------------------------------
# Jacobi polynomials
#
class jacobi(OrthogonalPolynomial):
r"""
Jacobi polynomial $P_n^{\left(\alpha, \beta\right)}(x)$.
Explanation
===========
``jacobi(n, alpha, beta, x)`` gives the $n$th Jacobi polynomial
in $x$, $P_n^{\left(\alpha, \beta\right)}(x)$.
The Jacobi polynomials are orthogonal on $[-1, 1]$ with respect
to the weight $\left(1-x\right)^\alpha \left(1+x\right)^\beta$.
Examples
========
>>> from sympy import jacobi, S, conjugate, diff
>>> from sympy.abc import a, b, n, x
>>> jacobi(0, a, b, x)
1
>>> jacobi(1, a, b, x)
a/2 - b/2 + x*(a/2 + b/2 + 1)
>>> jacobi(2, a, b, x)
a**2/8 - a*b/4 - a/8 + b**2/8 - b/8 + x**2*(a**2/8 + a*b/4 + 7*a/8 + b**2/8 + 7*b/8 + 3/2) + x*(a**2/4 + 3*a/4 - b**2/4 - 3*b/4) - 1/2
>>> jacobi(n, a, b, x)
jacobi(n, a, b, x)
>>> jacobi(n, a, a, x)
RisingFactorial(a + 1, n)*gegenbauer(n,
a + 1/2, x)/RisingFactorial(2*a + 1, n)
>>> jacobi(n, 0, 0, x)
legendre(n, x)
>>> jacobi(n, S(1)/2, S(1)/2, x)
RisingFactorial(3/2, n)*chebyshevu(n, x)/factorial(n + 1)
>>> jacobi(n, -S(1)/2, -S(1)/2, x)
RisingFactorial(1/2, n)*chebyshevt(n, x)/factorial(n)
>>> jacobi(n, a, b, -x)
(-1)**n*jacobi(n, b, a, x)
>>> jacobi(n, a, b, 0)
gamma(a + n + 1)*hyper((-n, -b - n), (a + 1,), -1)/(2**n*factorial(n)*gamma(a + 1))
>>> jacobi(n, a, b, 1)
RisingFactorial(a + 1, n)/factorial(n)
>>> conjugate(jacobi(n, a, b, x))
jacobi(n, conjugate(a), conjugate(b), conjugate(x))
>>> diff(jacobi(n,a,b,x), x)
(a/2 + b/2 + n/2 + 1/2)*jacobi(n - 1, a + 1, b + 1, x)
See Also
========
gegenbauer,
chebyshevt_root, chebyshevu, chebyshevu_root,
legendre, assoc_legendre,
hermite, hermite_prob,
laguerre, assoc_laguerre,
sympy.polys.orthopolys.jacobi_poly,
sympy.polys.orthopolys.gegenbauer_poly
sympy.polys.orthopolys.chebyshevt_poly
sympy.polys.orthopolys.chebyshevu_poly
sympy.polys.orthopolys.hermite_poly
sympy.polys.orthopolys.legendre_poly
sympy.polys.orthopolys.laguerre_poly
References
==========
.. [1] https://en.wikipedia.org/wiki/Jacobi_polynomials
.. [2] https://mathworld.wolfram.com/JacobiPolynomial.html
.. [3] https://functions.wolfram.com/Polynomials/JacobiP/
"""
@classmethod
def eval(cls, n, a, b, x):
# Simplify to other polynomials
# P^{a, a}_n(x)
if a == b:
if a == Rational(-1, 2):
return RisingFactorial(S.Half, n) / factorial(n) * chebyshevt(n, x)
elif a.is_zero:
return legendre(n, x)
elif a == S.Half:
return RisingFactorial(3*S.Half, n) / factorial(n + 1) * chebyshevu(n, x)
else:
return RisingFactorial(a + 1, n) / RisingFactorial(2*a + 1, n) * gegenbauer(n, a + S.Half, x)
elif b == -a:
# P^{a, -a}_n(x)
return gamma(n + a + 1) / gamma(n + 1) * (1 + x)**(a/2) / (1 - x)**(a/2) * assoc_legendre(n, -a, x)
if not n.is_Number:
# Symbolic result P^{a,b}_n(x)
# P^{a,b}_n(-x) ---> (-1)**n * P^{b,a}_n(-x)
if x.could_extract_minus_sign():
return S.NegativeOne**n * jacobi(n, b, a, -x)
# We can evaluate for some special values of x
if x.is_zero:
return (2**(-n) * gamma(a + n + 1) / (gamma(a + 1) * factorial(n)) *
hyper([-b - n, -n], [a + 1], -1))
if x == S.One:
return RisingFactorial(a + 1, n) / factorial(n)
elif x is S.Infinity:
if n.is_positive:
# Make sure a+b+2*n \notin Z
if (a + b + 2*n).is_integer:
raise ValueError("Error. a + b + 2*n should not be an integer.")
return RisingFactorial(a + b + n + 1, n) * S.Infinity
else:
# n is a given fixed integer, evaluate into polynomial
return jacobi_poly(n, a, b, x)
def fdiff(self, argindex=4):
from sympy.concrete.summations import Sum
if argindex == 1:
# Diff wrt n
raise ArgumentIndexError(self, argindex)
elif argindex == 2:
# Diff wrt a
n, a, b, x = self.args
k = Dummy("k")
f1 = 1 / (a + b + n + k + 1)
f2 = ((a + b + 2*k + 1) * RisingFactorial(b + k + 1, n - k) /
((n - k) * RisingFactorial(a + b + k + 1, n - k)))
return Sum(f1 * (jacobi(n, a, b, x) + f2*jacobi(k, a, b, x)), (k, 0, n - 1))
elif argindex == 3:
# Diff wrt b
n, a, b, x = self.args
k = Dummy("k")
f1 = 1 / (a + b + n + k + 1)
f2 = (-1)**(n - k) * ((a + b + 2*k + 1) * RisingFactorial(a + k + 1, n - k) /
((n - k) * RisingFactorial(a + b + k + 1, n - k)))
return Sum(f1 * (jacobi(n, a, b, x) + f2*jacobi(k, a, b, x)), (k, 0, n - 1))
elif argindex == 4:
# Diff wrt x
n, a, b, x = self.args
return S.Half * (a + b + n + 1) * jacobi(n - 1, a + 1, b + 1, x)
else:
raise ArgumentIndexError(self, argindex)
def _eval_rewrite_as_Sum(self, n, a, b, x, **kwargs):
from sympy.concrete.summations import Sum
# Make sure n \in N
if n.is_negative or n.is_integer is False:
raise ValueError("Error: n should be a non-negative integer.")
k = Dummy("k")
kern = (RisingFactorial(-n, k) * RisingFactorial(a + b + n + 1, k) * RisingFactorial(a + k + 1, n - k) /
factorial(k) * ((1 - x)/2)**k)
return 1 / factorial(n) * Sum(kern, (k, 0, n))
def _eval_rewrite_as_polynomial(self, n, a, b, x, **kwargs):
# This function is just kept for backwards compatibility
# but should not be used
return self._eval_rewrite_as_Sum(n, a, b, x, **kwargs)
def _eval_conjugate(self):
n, a, b, x = self.args
return self.func(n, a.conjugate(), b.conjugate(), x.conjugate())
def jacobi_normalized(n, a, b, x):
r"""
Jacobi polynomial $P_n^{\left(\alpha, \beta\right)}(x)$.
Explanation
===========
``jacobi_normalized(n, alpha, beta, x)`` gives the $n$th
Jacobi polynomial in $x$, $P_n^{\left(\alpha, \beta\right)}(x)$.
The Jacobi polynomials are orthogonal on $[-1, 1]$ with respect
to the weight $\left(1-x\right)^\alpha \left(1+x\right)^\beta$.
This functions returns the polynomials normilzed:
.. math::
\int_{-1}^{1}
P_m^{\left(\alpha, \beta\right)}(x)
P_n^{\left(\alpha, \beta\right)}(x)
(1-x)^{\alpha} (1+x)^{\beta} \mathrm{d}x
= \delta_{m,n}
Examples
========
>>> from sympy import jacobi_normalized
>>> from sympy.abc import n,a,b,x
>>> jacobi_normalized(n, a, b, x)
jacobi(n, a, b, x)/sqrt(2**(a + b + 1)*gamma(a + n + 1)*gamma(b + n + 1)/((a + b + 2*n + 1)*factorial(n)*gamma(a + b + n + 1)))
Parameters
==========
n : integer degree of polynomial
a : alpha value
b : beta value
x : symbol
See Also
========
gegenbauer,
chebyshevt_root, chebyshevu, chebyshevu_root,
legendre, assoc_legendre,
hermite, hermite_prob,
laguerre, assoc_laguerre,
sympy.polys.orthopolys.jacobi_poly,
sympy.polys.orthopolys.gegenbauer_poly
sympy.polys.orthopolys.chebyshevt_poly
sympy.polys.orthopolys.chebyshevu_poly
sympy.polys.orthopolys.hermite_poly
sympy.polys.orthopolys.legendre_poly
sympy.polys.orthopolys.laguerre_poly
References
==========
.. [1] https://en.wikipedia.org/wiki/Jacobi_polynomials
.. [2] https://mathworld.wolfram.com/JacobiPolynomial.html
.. [3] https://functions.wolfram.com/Polynomials/JacobiP/
"""
nfactor = (S(2)**(a + b + 1) * (gamma(n + a + 1) * gamma(n + b + 1))
/ (2*n + a + b + 1) / (factorial(n) * gamma(n + a + b + 1)))
return jacobi(n, a, b, x) / sqrt(nfactor)
#----------------------------------------------------------------------------
# Gegenbauer polynomials
#
class gegenbauer(OrthogonalPolynomial):
r"""
Gegenbauer polynomial $C_n^{\left(\alpha\right)}(x)$.
Explanation
===========
``gegenbauer(n, alpha, x)`` gives the $n$th Gegenbauer polynomial
in $x$, $C_n^{\left(\alpha\right)}(x)$.
The Gegenbauer polynomials are orthogonal on $[-1, 1]$ with
respect to the weight $\left(1-x^2\right)^{\alpha-\frac{1}{2}}$.
Examples
========
>>> from sympy import gegenbauer, conjugate, diff
>>> from sympy.abc import n,a,x
>>> gegenbauer(0, a, x)
1
>>> gegenbauer(1, a, x)
2*a*x
>>> gegenbauer(2, a, x)
-a + x**2*(2*a**2 + 2*a)
>>> gegenbauer(3, a, x)
x**3*(4*a**3/3 + 4*a**2 + 8*a/3) + x*(-2*a**2 - 2*a)
>>> gegenbauer(n, a, x)
gegenbauer(n, a, x)
>>> gegenbauer(n, a, -x)
(-1)**n*gegenbauer(n, a, x)
>>> gegenbauer(n, a, 0)
2**n*sqrt(pi)*gamma(a + n/2)/(gamma(a)*gamma(1/2 - n/2)*gamma(n + 1))
>>> gegenbauer(n, a, 1)
gamma(2*a + n)/(gamma(2*a)*gamma(n + 1))
>>> conjugate(gegenbauer(n, a, x))
gegenbauer(n, conjugate(a), conjugate(x))
>>> diff(gegenbauer(n, a, x), x)
2*a*gegenbauer(n - 1, a + 1, x)
See Also
========
jacobi,
chebyshevt_root, chebyshevu, chebyshevu_root,
legendre, assoc_legendre,
hermite, hermite_prob,
laguerre, assoc_laguerre,
sympy.polys.orthopolys.jacobi_poly
sympy.polys.orthopolys.gegenbauer_poly
sympy.polys.orthopolys.chebyshevt_poly
sympy.polys.orthopolys.chebyshevu_poly
sympy.polys.orthopolys.hermite_poly
sympy.polys.orthopolys.hermite_prob_poly
sympy.polys.orthopolys.legendre_poly
sympy.polys.orthopolys.laguerre_poly
References
==========
.. [1] https://en.wikipedia.org/wiki/Gegenbauer_polynomials
.. [2] https://mathworld.wolfram.com/GegenbauerPolynomial.html
.. [3] https://functions.wolfram.com/Polynomials/GegenbauerC3/
"""
@classmethod
def eval(cls, n, a, x):
# For negative n the polynomials vanish
# See https://functions.wolfram.com/Polynomials/GegenbauerC3/03/01/03/0012/
if n.is_negative:
return S.Zero
# Some special values for fixed a
if a == S.Half:
return legendre(n, x)
elif a == S.One:
return chebyshevu(n, x)
elif a == S.NegativeOne:
return S.Zero
if not n.is_Number:
# Handle this before the general sign extraction rule
if x == S.NegativeOne:
if (re(a) > S.Half) == True:
return S.ComplexInfinity
else:
return (cos(S.Pi*(a+n)) * sec(S.Pi*a) * gamma(2*a+n) /
(gamma(2*a) * gamma(n+1)))
# Symbolic result C^a_n(x)
# C^a_n(-x) ---> (-1)**n * C^a_n(x)
if x.could_extract_minus_sign():
return S.NegativeOne**n * gegenbauer(n, a, -x)
# We can evaluate for some special values of x
if x.is_zero:
return (2**n * sqrt(S.Pi) * gamma(a + S.Half*n) /
(gamma((1 - n)/2) * gamma(n + 1) * gamma(a)) )
if x == S.One:
return gamma(2*a + n) / (gamma(2*a) * gamma(n + 1))
elif x is S.Infinity:
if n.is_positive:
return RisingFactorial(a, n) * S.Infinity
else:
# n is a given fixed integer, evaluate into polynomial
return gegenbauer_poly(n, a, x)
def fdiff(self, argindex=3):
from sympy.concrete.summations import Sum
if argindex == 1:
# Diff wrt n
raise ArgumentIndexError(self, argindex)
elif argindex == 2:
# Diff wrt a
n, a, x = self.args
k = Dummy("k")
factor1 = 2 * (1 + (-1)**(n - k)) * (k + a) / ((k +
n + 2*a) * (n - k))
factor2 = 2*(k + 1) / ((k + 2*a) * (2*k + 2*a + 1)) + \
2 / (k + n + 2*a)
kern = factor1*gegenbauer(k, a, x) + factor2*gegenbauer(n, a, x)
return Sum(kern, (k, 0, n - 1))
elif argindex == 3:
# Diff wrt x
n, a, x = self.args
return 2*a*gegenbauer(n - 1, a + 1, x)
else:
raise ArgumentIndexError(self, argindex)
def _eval_rewrite_as_Sum(self, n, a, x, **kwargs):
from sympy.concrete.summations import Sum
k = Dummy("k")
kern = ((-1)**k * RisingFactorial(a, n - k) * (2*x)**(n - 2*k) /
(factorial(k) * factorial(n - 2*k)))
return Sum(kern, (k, 0, floor(n/2)))
def _eval_rewrite_as_polynomial(self, n, a, x, **kwargs):
# This function is just kept for backwards compatibility
# but should not be used
return self._eval_rewrite_as_Sum(n, a, x, **kwargs)
def _eval_conjugate(self):
n, a, x = self.args
return self.func(n, a.conjugate(), x.conjugate())
#----------------------------------------------------------------------------
# Chebyshev polynomials of first and second kind
#
class chebyshevt(OrthogonalPolynomial):
r"""
Chebyshev polynomial of the first kind, $T_n(x)$.
Explanation
===========
``chebyshevt(n, x)`` gives the $n$th Chebyshev polynomial (of the first
kind) in $x$, $T_n(x)$.
The Chebyshev polynomials of the first kind are orthogonal on
$[-1, 1]$ with respect to the weight $\frac{1}{\sqrt{1-x^2}}$.
Examples
========
>>> from sympy import chebyshevt, diff
>>> from sympy.abc import n,x
>>> chebyshevt(0, x)
1
>>> chebyshevt(1, x)
x
>>> chebyshevt(2, x)
2*x**2 - 1
>>> chebyshevt(n, x)
chebyshevt(n, x)
>>> chebyshevt(n, -x)
(-1)**n*chebyshevt(n, x)
>>> chebyshevt(-n, x)
chebyshevt(n, x)
>>> chebyshevt(n, 0)
cos(pi*n/2)
>>> chebyshevt(n, -1)
(-1)**n
>>> diff(chebyshevt(n, x), x)
n*chebyshevu(n - 1, x)
See Also
========
jacobi, gegenbauer,
chebyshevt_root, chebyshevu, chebyshevu_root,
legendre, assoc_legendre,
hermite, hermite_prob,
laguerre, assoc_laguerre,
sympy.polys.orthopolys.jacobi_poly
sympy.polys.orthopolys.gegenbauer_poly
sympy.polys.orthopolys.chebyshevt_poly
sympy.polys.orthopolys.chebyshevu_poly
sympy.polys.orthopolys.hermite_poly
sympy.polys.orthopolys.hermite_prob_poly
sympy.polys.orthopolys.legendre_poly
sympy.polys.orthopolys.laguerre_poly
References
==========
.. [1] https://en.wikipedia.org/wiki/Chebyshev_polynomial
.. [2] https://mathworld.wolfram.com/ChebyshevPolynomialoftheFirstKind.html
.. [3] https://mathworld.wolfram.com/ChebyshevPolynomialoftheSecondKind.html
.. [4] https://functions.wolfram.com/Polynomials/ChebyshevT/
.. [5] https://functions.wolfram.com/Polynomials/ChebyshevU/
"""
_ortho_poly = staticmethod(chebyshevt_poly)
@classmethod
def eval(cls, n, x):
if not n.is_Number:
# Symbolic result T_n(x)
# T_n(-x) ---> (-1)**n * T_n(x)
if x.could_extract_minus_sign():
return S.NegativeOne**n * chebyshevt(n, -x)
# T_{-n}(x) ---> T_n(x)
if n.could_extract_minus_sign():
return chebyshevt(-n, x)
# We can evaluate for some special values of x
if x.is_zero:
return cos(S.Half * S.Pi * n)
if x == S.One:
return S.One
elif x is S.Infinity:
return S.Infinity
else:
# n is a given fixed integer, evaluate into polynomial
if n.is_negative:
# T_{-n}(x) == T_n(x)
return cls._eval_at_order(-n, x)
else:
return cls._eval_at_order(n, x)
def fdiff(self, argindex=2):
if argindex == 1:
# Diff wrt n
raise ArgumentIndexError(self, argindex)
elif argindex == 2:
# Diff wrt x
n, x = self.args
return n * chebyshevu(n - 1, x)
else:
raise ArgumentIndexError(self, argindex)
def _eval_rewrite_as_Sum(self, n, x, **kwargs):
from sympy.concrete.summations import Sum
k = Dummy("k")
kern = binomial(n, 2*k) * (x**2 - 1)**k * x**(n - 2*k)
return Sum(kern, (k, 0, floor(n/2)))
def _eval_rewrite_as_polynomial(self, n, x, **kwargs):
# This function is just kept for backwards compatibility
# but should not be used
return self._eval_rewrite_as_Sum(n, x, **kwargs)
class chebyshevu(OrthogonalPolynomial):
r"""
Chebyshev polynomial of the second kind, $U_n(x)$.
Explanation
===========
``chebyshevu(n, x)`` gives the $n$th Chebyshev polynomial of the second
kind in x, $U_n(x)$.
The Chebyshev polynomials of the second kind are orthogonal on
$[-1, 1]$ with respect to the weight $\sqrt{1-x^2}$.
Examples
========
>>> from sympy import chebyshevu, diff
>>> from sympy.abc import n,x
>>> chebyshevu(0, x)
1
>>> chebyshevu(1, x)
2*x
>>> chebyshevu(2, x)
4*x**2 - 1
>>> chebyshevu(n, x)
chebyshevu(n, x)
>>> chebyshevu(n, -x)
(-1)**n*chebyshevu(n, x)
>>> chebyshevu(-n, x)
-chebyshevu(n - 2, x)
>>> chebyshevu(n, 0)
cos(pi*n/2)
>>> chebyshevu(n, 1)
n + 1
>>> diff(chebyshevu(n, x), x)
(-x*chebyshevu(n, x) + (n + 1)*chebyshevt(n + 1, x))/(x**2 - 1)
See Also
========
jacobi, gegenbauer,
chebyshevt, chebyshevt_root, chebyshevu_root,
legendre, assoc_legendre,
hermite, hermite_prob,
laguerre, assoc_laguerre,
sympy.polys.orthopolys.jacobi_poly
sympy.polys.orthopolys.gegenbauer_poly
sympy.polys.orthopolys.chebyshevt_poly
sympy.polys.orthopolys.chebyshevu_poly
sympy.polys.orthopolys.hermite_poly
sympy.polys.orthopolys.hermite_prob_poly
sympy.polys.orthopolys.legendre_poly
sympy.polys.orthopolys.laguerre_poly
References
==========
.. [1] https://en.wikipedia.org/wiki/Chebyshev_polynomial
.. [2] https://mathworld.wolfram.com/ChebyshevPolynomialoftheFirstKind.html
.. [3] https://mathworld.wolfram.com/ChebyshevPolynomialoftheSecondKind.html
.. [4] https://functions.wolfram.com/Polynomials/ChebyshevT/
.. [5] https://functions.wolfram.com/Polynomials/ChebyshevU/
"""
_ortho_poly = staticmethod(chebyshevu_poly)
@classmethod
def eval(cls, n, x):
if not n.is_Number:
# Symbolic result U_n(x)
# U_n(-x) ---> (-1)**n * U_n(x)
if x.could_extract_minus_sign():
return S.NegativeOne**n * chebyshevu(n, -x)
# U_{-n}(x) ---> -U_{n-2}(x)
if n.could_extract_minus_sign():
if n == S.NegativeOne:
# n can not be -1 here
return S.Zero
elif not (-n - 2).could_extract_minus_sign():
return -chebyshevu(-n - 2, x)
# We can evaluate for some special values of x
if x.is_zero:
return cos(S.Half * S.Pi * n)
if x == S.One:
return S.One + n
elif x is S.Infinity:
return S.Infinity
else:
# n is a given fixed integer, evaluate into polynomial
if n.is_negative:
# U_{-n}(x) ---> -U_{n-2}(x)
if n == S.NegativeOne:
return S.Zero
else:
return -cls._eval_at_order(-n - 2, x)
else:
return cls._eval_at_order(n, x)
def fdiff(self, argindex=2):
if argindex == 1:
# Diff wrt n
raise ArgumentIndexError(self, argindex)
elif argindex == 2:
# Diff wrt x
n, x = self.args
return ((n + 1) * chebyshevt(n + 1, x) - x * chebyshevu(n, x)) / (x**2 - 1)
else:
raise ArgumentIndexError(self, argindex)
def _eval_rewrite_as_Sum(self, n, x, **kwargs):
from sympy.concrete.summations import Sum
k = Dummy("k")
kern = S.NegativeOne**k * factorial(
n - k) * (2*x)**(n - 2*k) / (factorial(k) * factorial(n - 2*k))
return Sum(kern, (k, 0, floor(n/2)))
def _eval_rewrite_as_polynomial(self, n, x, **kwargs):
# This function is just kept for backwards compatibility
# but should not be used
return self._eval_rewrite_as_Sum(n, x, **kwargs)
class chebyshevt_root(Function):
r"""
``chebyshev_root(n, k)`` returns the $k$th root (indexed from zero) of
the $n$th Chebyshev polynomial of the first kind; that is, if
$0 \le k < n$, ``chebyshevt(n, chebyshevt_root(n, k)) == 0``.
Examples
========
>>> from sympy import chebyshevt, chebyshevt_root
>>> chebyshevt_root(3, 2)
-sqrt(3)/2
>>> chebyshevt(3, chebyshevt_root(3, 2))
0
See Also
========
jacobi, gegenbauer,
chebyshevt, chebyshevu, chebyshevu_root,
legendre, assoc_legendre,
hermite, hermite_prob,
laguerre, assoc_laguerre,
sympy.polys.orthopolys.jacobi_poly
sympy.polys.orthopolys.gegenbauer_poly
sympy.polys.orthopolys.chebyshevt_poly
sympy.polys.orthopolys.chebyshevu_poly
sympy.polys.orthopolys.hermite_poly
sympy.polys.orthopolys.hermite_prob_poly
sympy.polys.orthopolys.legendre_poly
sympy.polys.orthopolys.laguerre_poly
"""
@classmethod
def eval(cls, n, k):
if not ((0 <= k) and (k < n)):
raise ValueError("must have 0 <= k < n, "
"got k = %s and n = %s" % (k, n))
return cos(S.Pi*(2*k + 1)/(2*n))
class chebyshevu_root(Function):
r"""
``chebyshevu_root(n, k)`` returns the $k$th root (indexed from zero) of the
$n$th Chebyshev polynomial of the second kind; that is, if $0 \le k < n$,
``chebyshevu(n, chebyshevu_root(n, k)) == 0``.
Examples
========
>>> from sympy import chebyshevu, chebyshevu_root
>>> chebyshevu_root(3, 2)
-sqrt(2)/2
>>> chebyshevu(3, chebyshevu_root(3, 2))
0
See Also
========
chebyshevt, chebyshevt_root, chebyshevu,
legendre, assoc_legendre,
hermite, hermite_prob,
laguerre, assoc_laguerre,
sympy.polys.orthopolys.jacobi_poly
sympy.polys.orthopolys.gegenbauer_poly
sympy.polys.orthopolys.chebyshevt_poly
sympy.polys.orthopolys.chebyshevu_poly
sympy.polys.orthopolys.hermite_poly
sympy.polys.orthopolys.hermite_prob_poly
sympy.polys.orthopolys.legendre_poly
sympy.polys.orthopolys.laguerre_poly
"""
@classmethod
def eval(cls, n, k):
if not ((0 <= k) and (k < n)):
raise ValueError("must have 0 <= k < n, "
"got k = %s and n = %s" % (k, n))
return cos(S.Pi*(k + 1)/(n + 1))
#----------------------------------------------------------------------------
# Legendre polynomials and Associated Legendre polynomials
#
class legendre(OrthogonalPolynomial):
r"""
``legendre(n, x)`` gives the $n$th Legendre polynomial of $x$, $P_n(x)$
Explanation
===========
The Legendre polynomials are orthogonal on $[-1, 1]$ with respect to
the constant weight 1. They satisfy $P_n(1) = 1$ for all $n$; further,
$P_n$ is odd for odd $n$ and even for even $n$.
Examples
========
>>> from sympy import legendre, diff
>>> from sympy.abc import x, n
>>> legendre(0, x)
1
>>> legendre(1, x)
x
>>> legendre(2, x)
3*x**2/2 - 1/2
>>> legendre(n, x)
legendre(n, x)
>>> diff(legendre(n,x), x)
n*(x*legendre(n, x) - legendre(n - 1, x))/(x**2 - 1)
See Also
========
jacobi, gegenbauer,
chebyshevt, chebyshevt_root, chebyshevu, chebyshevu_root,
assoc_legendre,
hermite, hermite_prob,
laguerre, assoc_laguerre,
sympy.polys.orthopolys.jacobi_poly
sympy.polys.orthopolys.gegenbauer_poly
sympy.polys.orthopolys.chebyshevt_poly
sympy.polys.orthopolys.chebyshevu_poly
sympy.polys.orthopolys.hermite_poly
sympy.polys.orthopolys.hermite_prob_poly
sympy.polys.orthopolys.legendre_poly
sympy.polys.orthopolys.laguerre_poly
References
==========
.. [1] https://en.wikipedia.org/wiki/Legendre_polynomial
.. [2] https://mathworld.wolfram.com/LegendrePolynomial.html
.. [3] https://functions.wolfram.com/Polynomials/LegendreP/
.. [4] https://functions.wolfram.com/Polynomials/LegendreP2/
"""
_ortho_poly = staticmethod(legendre_poly)
@classmethod
def eval(cls, n, x):
if not n.is_Number:
# Symbolic result L_n(x)
# L_n(-x) ---> (-1)**n * L_n(x)
if x.could_extract_minus_sign():
return S.NegativeOne**n * legendre(n, -x)
# L_{-n}(x) ---> L_{n-1}(x)
if n.could_extract_minus_sign() and not(-n - 1).could_extract_minus_sign():
return legendre(-n - S.One, x)
# We can evaluate for some special values of x
if x.is_zero:
return sqrt(S.Pi)/(gamma(S.Half - n/2)*gamma(S.One + n/2))
elif x == S.One:
return S.One
elif x is S.Infinity:
return S.Infinity
else:
# n is a given fixed integer, evaluate into polynomial;
# L_{-n}(x) ---> L_{n-1}(x)
if n.is_negative:
n = -n - S.One
return cls._eval_at_order(n, x)
def fdiff(self, argindex=2):
if argindex == 1:
# Diff wrt n
raise ArgumentIndexError(self, argindex)
elif argindex == 2:
# Diff wrt x
# Find better formula, this is unsuitable for x = +/-1
# https://www.autodiff.org/ad16/Oral/Buecker_Legendre.pdf says
# at x = 1:
# n*(n + 1)/2 , m = 0
# oo , m = 1
# -(n-1)*n*(n+1)*(n+2)/4 , m = 2
# 0 , m = 3, 4, ..., n
#
# at x = -1
# (-1)**(n+1)*n*(n + 1)/2 , m = 0
# (-1)**n*oo , m = 1
# (-1)**n*(n-1)*n*(n+1)*(n+2)/4 , m = 2
# 0 , m = 3, 4, ..., n
n, x = self.args
return n/(x**2 - 1)*(x*legendre(n, x) - legendre(n - 1, x))
else:
raise ArgumentIndexError(self, argindex)
def _eval_rewrite_as_Sum(self, n, x, **kwargs):
from sympy.concrete.summations import Sum
k = Dummy("k")
kern = S.NegativeOne**k*binomial(n, k)**2*((1 + x)/2)**(n - k)*((1 - x)/2)**k
return Sum(kern, (k, 0, n))
def _eval_rewrite_as_polynomial(self, n, x, **kwargs):
# This function is just kept for backwards compatibility
# but should not be used
return self._eval_rewrite_as_Sum(n, x, **kwargs)
class assoc_legendre(Function):
r"""
``assoc_legendre(n, m, x)`` gives $P_n^m(x)$, where $n$ and $m$ are
the degree and order or an expression which is related to the nth
order Legendre polynomial, $P_n(x)$ in the following manner:
.. math::
P_n^m(x) = (-1)^m (1 - x^2)^{\frac{m}{2}}
\frac{\mathrm{d}^m P_n(x)}{\mathrm{d} x^m}
Explanation
===========
Associated Legendre polynomials are orthogonal on $[-1, 1]$ with:
- weight $= 1$ for the same $m$ and different $n$.
- weight $= \frac{1}{1-x^2}$ for the same $n$ and different $m$.
Examples
========
>>> from sympy import assoc_legendre
>>> from sympy.abc import x, m, n
>>> assoc_legendre(0,0, x)
1
>>> assoc_legendre(1,0, x)
x
>>> assoc_legendre(1,1, x)
-sqrt(1 - x**2)
>>> assoc_legendre(n,m,x)
assoc_legendre(n, m, x)
See Also
========
jacobi, gegenbauer,
chebyshevt, chebyshevt_root, chebyshevu, chebyshevu_root,
legendre,
hermite, hermite_prob,
laguerre, assoc_laguerre,
sympy.polys.orthopolys.jacobi_poly
sympy.polys.orthopolys.gegenbauer_poly
sympy.polys.orthopolys.chebyshevt_poly
sympy.polys.orthopolys.chebyshevu_poly
sympy.polys.orthopolys.hermite_poly
sympy.polys.orthopolys.hermite_prob_poly
sympy.polys.orthopolys.legendre_poly
sympy.polys.orthopolys.laguerre_poly
References
==========
.. [1] https://en.wikipedia.org/wiki/Associated_Legendre_polynomials
.. [2] https://mathworld.wolfram.com/LegendrePolynomial.html
.. [3] https://functions.wolfram.com/Polynomials/LegendreP/
.. [4] https://functions.wolfram.com/Polynomials/LegendreP2/
"""
@classmethod
def _eval_at_order(cls, n, m):
P = legendre_poly(n, _x, polys=True).diff((_x, m))
return S.NegativeOne**m * (1 - _x**2)**Rational(m, 2) * P.as_expr()
@classmethod
def eval(cls, n, m, x):
if m.could_extract_minus_sign():
# P^{-m}_n ---> F * P^m_n
return S.NegativeOne**(-m) * (factorial(m + n)/factorial(n - m)) * assoc_legendre(n, -m, x)
if m == 0:
# P^0_n ---> L_n
return legendre(n, x)
if x == 0:
return 2**m*sqrt(S.Pi) / (gamma((1 - m - n)/2)*gamma(1 - (m - n)/2))
if n.is_Number and m.is_Number and n.is_integer and m.is_integer:
if n.is_negative:
raise ValueError("%s : 1st index must be nonnegative integer (got %r)" % (cls, n))
if abs(m) > n:
raise ValueError("%s : abs('2nd index') must be <= '1st index' (got %r, %r)" % (cls, n, m))
return cls._eval_at_order(int(n), abs(int(m))).subs(_x, x)
def fdiff(self, argindex=3):
if argindex == 1:
# Diff wrt n
raise ArgumentIndexError(self, argindex)
elif argindex == 2:
# Diff wrt m
raise ArgumentIndexError(self, argindex)
elif argindex == 3:
# Diff wrt x
# Find better formula, this is unsuitable for x = 1
n, m, x = self.args
return 1/(x**2 - 1)*(x*n*assoc_legendre(n, m, x) - (m + n)*assoc_legendre(n - 1, m, x))
else:
raise ArgumentIndexError(self, argindex)
def _eval_rewrite_as_Sum(self, n, m, x, **kwargs):
from sympy.concrete.summations import Sum
k = Dummy("k")
kern = factorial(2*n - 2*k)/(2**n*factorial(n - k)*factorial(
k)*factorial(n - 2*k - m))*S.NegativeOne**k*x**(n - m - 2*k)
return (1 - x**2)**(m/2) * Sum(kern, (k, 0, floor((n - m)*S.Half)))
def _eval_rewrite_as_polynomial(self, n, m, x, **kwargs):
# This function is just kept for backwards compatibility
# but should not be used
return self._eval_rewrite_as_Sum(n, m, x, **kwargs)
def _eval_conjugate(self):
n, m, x = self.args
return self.func(n, m.conjugate(), x.conjugate())
#----------------------------------------------------------------------------
# Hermite polynomials
#
class hermite(OrthogonalPolynomial):
r"""
``hermite(n, x)`` gives the $n$th Hermite polynomial in $x$, $H_n(x)$.
Explanation
===========
The Hermite polynomials are orthogonal on $(-\infty, \infty)$
with respect to the weight $\exp\left(-x^2\right)$.
Examples
========
>>> from sympy import hermite, diff
>>> from sympy.abc import x, n
>>> hermite(0, x)
1
>>> hermite(1, x)
2*x
>>> hermite(2, x)
4*x**2 - 2
>>> hermite(n, x)
hermite(n, x)
>>> diff(hermite(n,x), x)
2*n*hermite(n - 1, x)
>>> hermite(n, -x)
(-1)**n*hermite(n, x)
See Also
========
jacobi, gegenbauer,
chebyshevt, chebyshevt_root, chebyshevu, chebyshevu_root,
legendre, assoc_legendre,
hermite_prob,
laguerre, assoc_laguerre,
sympy.polys.orthopolys.jacobi_poly
sympy.polys.orthopolys.gegenbauer_poly
sympy.polys.orthopolys.chebyshevt_poly
sympy.polys.orthopolys.chebyshevu_poly
sympy.polys.orthopolys.hermite_poly
sympy.polys.orthopolys.hermite_prob_poly
sympy.polys.orthopolys.legendre_poly
sympy.polys.orthopolys.laguerre_poly
References
==========
.. [1] https://en.wikipedia.org/wiki/Hermite_polynomial
.. [2] https://mathworld.wolfram.com/HermitePolynomial.html
.. [3] https://functions.wolfram.com/Polynomials/HermiteH/
"""
_ortho_poly = staticmethod(hermite_poly)
@classmethod
def eval(cls, n, x):
if not n.is_Number:
# Symbolic result H_n(x)
# H_n(-x) ---> (-1)**n * H_n(x)
if x.could_extract_minus_sign():
return S.NegativeOne**n * hermite(n, -x)
# We can evaluate for some special values of x
if x.is_zero:
return 2**n * sqrt(S.Pi) / gamma((S.One - n)/2)
elif x is S.Infinity:
return S.Infinity
else:
# n is a given fixed integer, evaluate into polynomial
if n.is_negative:
raise ValueError(
"The index n must be nonnegative integer (got %r)" % n)
else:
return cls._eval_at_order(n, x)
def fdiff(self, argindex=2):
if argindex == 1:
# Diff wrt n
raise ArgumentIndexError(self, argindex)
elif argindex == 2:
# Diff wrt x
n, x = self.args
return 2*n*hermite(n - 1, x)
else:
raise ArgumentIndexError(self, argindex)
def _eval_rewrite_as_Sum(self, n, x, **kwargs):
from sympy.concrete.summations import Sum
k = Dummy("k")
kern = S.NegativeOne**k / (factorial(k)*factorial(n - 2*k)) * (2*x)**(n - 2*k)
return factorial(n)*Sum(kern, (k, 0, floor(n/2)))
def _eval_rewrite_as_polynomial(self, n, x, **kwargs):
# This function is just kept for backwards compatibility
# but should not be used
return self._eval_rewrite_as_Sum(n, x, **kwargs)
def _eval_rewrite_as_hermite_prob(self, n, x, **kwargs):
return sqrt(2)**n * hermite_prob(n, x*sqrt(2))
class hermite_prob(OrthogonalPolynomial):
r"""
``hermite_prob(n, x)`` gives the $n$th probabilist's Hermite polynomial
in $x$, $He_n(x)$.
Explanation
===========
The probabilist's Hermite polynomials are orthogonal on $(-\infty, \infty)$
with respect to the weight $\exp\left(-\frac{x^2}{2}\right)$. They are monic
polynomials, related to the plain Hermite polynomials (:py:class:`~.hermite`) by
.. math :: He_n(x) = 2^{-n/2} H_n(x/\sqrt{2})
Examples
========
>>> from sympy import hermite_prob, diff, I
>>> from sympy.abc import x, n
>>> hermite_prob(1, x)
x
>>> hermite_prob(5, x)
x**5 - 10*x**3 + 15*x
>>> diff(hermite_prob(n,x), x)
n*hermite_prob(n - 1, x)
>>> hermite_prob(n, -x)
(-1)**n*hermite_prob(n, x)
The sum of absolute values of coefficients of $He_n(x)$ is the number of
matchings in the complete graph $K_n$ or telephone number, A000085 in the OEIS:
>>> [hermite_prob(n,I) / I**n for n in range(11)]
[1, 1, 2, 4, 10, 26, 76, 232, 764, 2620, 9496]
See Also
========
jacobi, gegenbauer,
chebyshevt, chebyshevt_root, chebyshevu, chebyshevu_root,
legendre, assoc_legendre,
hermite,
laguerre, assoc_laguerre,
sympy.polys.orthopolys.jacobi_poly
sympy.polys.orthopolys.gegenbauer_poly
sympy.polys.orthopolys.chebyshevt_poly
sympy.polys.orthopolys.chebyshevu_poly
sympy.polys.orthopolys.hermite_poly
sympy.polys.orthopolys.hermite_prob_poly
sympy.polys.orthopolys.legendre_poly
sympy.polys.orthopolys.laguerre_poly
References
==========
.. [1] https://en.wikipedia.org/wiki/Hermite_polynomial
.. [2] https://mathworld.wolfram.com/HermitePolynomial.html
"""
_ortho_poly = staticmethod(hermite_prob_poly)
@classmethod
def eval(cls, n, x):
if not n.is_Number:
if x.could_extract_minus_sign():
return S.NegativeOne**n * hermite_prob(n, -x)
if x.is_zero:
return sqrt(S.Pi) / gamma((S.One-n) / 2)
elif x is S.Infinity:
return S.Infinity
else:
if n.is_negative:
ValueError("n must be a nonnegative integer, not %r" % n)
else:
return cls._eval_at_order(n, x)
def fdiff(self, argindex=2):
if argindex == 2:
n, x = self.args
return n*hermite_prob(n-1, x)
else:
raise ArgumentIndexError(self, argindex)
def _eval_rewrite_as_Sum(self, n, x, **kwargs):
from sympy.concrete.summations import Sum
k = Dummy("k")
kern = (-S.Half)**k * x**(n-2*k) / (factorial(k) * factorial(n-2*k))
return factorial(n)*Sum(kern, (k, 0, floor(n/2)))
def _eval_rewrite_as_polynomial(self, n, x, **kwargs):
# This function is just kept for backwards compatibility
# but should not be used
return self._eval_rewrite_as_Sum(n, x, **kwargs)
def _eval_rewrite_as_hermite(self, n, x, **kwargs):
return sqrt(2)**(-n) * hermite(n, x/sqrt(2))
#----------------------------------------------------------------------------
# Laguerre polynomials
#
class laguerre(OrthogonalPolynomial):
r"""
Returns the $n$th Laguerre polynomial in $x$, $L_n(x)$.
Examples
========
>>> from sympy import laguerre, diff
>>> from sympy.abc import x, n
>>> laguerre(0, x)
1
>>> laguerre(1, x)
1 - x
>>> laguerre(2, x)
x**2/2 - 2*x + 1
>>> laguerre(3, x)
-x**3/6 + 3*x**2/2 - 3*x + 1
>>> laguerre(n, x)
laguerre(n, x)
>>> diff(laguerre(n, x), x)
-assoc_laguerre(n - 1, 1, x)
Parameters
==========
n : int
Degree of Laguerre polynomial. Must be `n \ge 0`.
See Also
========
jacobi, gegenbauer,
chebyshevt, chebyshevt_root, chebyshevu, chebyshevu_root,
legendre, assoc_legendre,
hermite, hermite_prob,
assoc_laguerre,
sympy.polys.orthopolys.jacobi_poly
sympy.polys.orthopolys.gegenbauer_poly
sympy.polys.orthopolys.chebyshevt_poly
sympy.polys.orthopolys.chebyshevu_poly
sympy.polys.orthopolys.hermite_poly
sympy.polys.orthopolys.hermite_prob_poly
sympy.polys.orthopolys.legendre_poly
sympy.polys.orthopolys.laguerre_poly
References
==========
.. [1] https://en.wikipedia.org/wiki/Laguerre_polynomial
.. [2] https://mathworld.wolfram.com/LaguerrePolynomial.html
.. [3] https://functions.wolfram.com/Polynomials/LaguerreL/
.. [4] https://functions.wolfram.com/Polynomials/LaguerreL3/
"""
_ortho_poly = staticmethod(laguerre_poly)
@classmethod
def eval(cls, n, x):
if n.is_integer is False:
raise ValueError("Error: n should be an integer.")
if not n.is_Number:
# Symbolic result L_n(x)
# L_{n}(-x) ---> exp(-x) * L_{-n-1}(x)
# L_{-n}(x) ---> exp(x) * L_{n-1}(-x)
if n.could_extract_minus_sign() and not(-n - 1).could_extract_minus_sign():
return exp(x)*laguerre(-n - 1, -x)
# We can evaluate for some special values of x
if x.is_zero:
return S.One
elif x is S.NegativeInfinity:
return S.Infinity
elif x is S.Infinity:
return S.NegativeOne**n * S.Infinity
else:
if n.is_negative:
return exp(x)*laguerre(-n - 1, -x)
else:
return cls._eval_at_order(n, x)
def fdiff(self, argindex=2):
if argindex == 1:
# Diff wrt n
raise ArgumentIndexError(self, argindex)
elif argindex == 2:
# Diff wrt x
n, x = self.args
return -assoc_laguerre(n - 1, 1, x)
else:
raise ArgumentIndexError(self, argindex)
def _eval_rewrite_as_Sum(self, n, x, **kwargs):
from sympy.concrete.summations import Sum
# Make sure n \in N_0
if n.is_negative:
return exp(x) * self._eval_rewrite_as_Sum(-n - 1, -x, **kwargs)
if n.is_integer is False:
raise ValueError("Error: n should be an integer.")
k = Dummy("k")
kern = RisingFactorial(-n, k) / factorial(k)**2 * x**k
return Sum(kern, (k, 0, n))
def _eval_rewrite_as_polynomial(self, n, x, **kwargs):
# This function is just kept for backwards compatibility
# but should not be used
return self._eval_rewrite_as_Sum(n, x, **kwargs)
class assoc_laguerre(OrthogonalPolynomial):
r"""
Returns the $n$th generalized Laguerre polynomial in $x$, $L_n(x)$.
Examples
========
>>> from sympy import assoc_laguerre, diff
>>> from sympy.abc import x, n, a
>>> assoc_laguerre(0, a, x)
1
>>> assoc_laguerre(1, a, x)
a - x + 1
>>> assoc_laguerre(2, a, x)
a**2/2 + 3*a/2 + x**2/2 + x*(-a - 2) + 1
>>> assoc_laguerre(3, a, x)
a**3/6 + a**2 + 11*a/6 - x**3/6 + x**2*(a/2 + 3/2) +
x*(-a**2/2 - 5*a/2 - 3) + 1
>>> assoc_laguerre(n, a, 0)
binomial(a + n, a)
>>> assoc_laguerre(n, a, x)
assoc_laguerre(n, a, x)
>>> assoc_laguerre(n, 0, x)
laguerre(n, x)
>>> diff(assoc_laguerre(n, a, x), x)
-assoc_laguerre(n - 1, a + 1, x)
>>> diff(assoc_laguerre(n, a, x), a)
Sum(assoc_laguerre(_k, a, x)/(-a + n), (_k, 0, n - 1))
Parameters
==========
n : int
Degree of Laguerre polynomial. Must be `n \ge 0`.
alpha : Expr
Arbitrary expression. For ``alpha=0`` regular Laguerre
polynomials will be generated.
See Also
========
jacobi, gegenbauer,
chebyshevt, chebyshevt_root, chebyshevu, chebyshevu_root,
legendre, assoc_legendre,
hermite, hermite_prob,
laguerre,
sympy.polys.orthopolys.jacobi_poly
sympy.polys.orthopolys.gegenbauer_poly
sympy.polys.orthopolys.chebyshevt_poly
sympy.polys.orthopolys.chebyshevu_poly
sympy.polys.orthopolys.hermite_poly
sympy.polys.orthopolys.hermite_prob_poly
sympy.polys.orthopolys.legendre_poly
sympy.polys.orthopolys.laguerre_poly
References
==========
.. [1] https://en.wikipedia.org/wiki/Laguerre_polynomial#Generalized_Laguerre_polynomials
.. [2] https://mathworld.wolfram.com/AssociatedLaguerrePolynomial.html
.. [3] https://functions.wolfram.com/Polynomials/LaguerreL/
.. [4] https://functions.wolfram.com/Polynomials/LaguerreL3/
"""
@classmethod
def eval(cls, n, alpha, x):
# L_{n}^{0}(x) ---> L_{n}(x)
if alpha.is_zero:
return laguerre(n, x)
if not n.is_Number:
# We can evaluate for some special values of x
if x.is_zero:
return binomial(n + alpha, alpha)
elif x is S.Infinity and n > 0:
return S.NegativeOne**n * S.Infinity
elif x is S.NegativeInfinity and n > 0:
return S.Infinity
else:
# n is a given fixed integer, evaluate into polynomial
if n.is_negative:
raise ValueError(
"The index n must be nonnegative integer (got %r)" % n)
else:
return laguerre_poly(n, x, alpha)
def fdiff(self, argindex=3):
from sympy.concrete.summations import Sum
if argindex == 1:
# Diff wrt n
raise ArgumentIndexError(self, argindex)
elif argindex == 2:
# Diff wrt alpha
n, alpha, x = self.args
k = Dummy("k")
return Sum(assoc_laguerre(k, alpha, x) / (n - alpha), (k, 0, n - 1))
elif argindex == 3:
# Diff wrt x
n, alpha, x = self.args
return -assoc_laguerre(n - 1, alpha + 1, x)
else:
raise ArgumentIndexError(self, argindex)
def _eval_rewrite_as_Sum(self, n, alpha, x, **kwargs):
from sympy.concrete.summations import Sum
# Make sure n \in N_0
if n.is_negative or n.is_integer is False:
raise ValueError("Error: n should be a non-negative integer.")
k = Dummy("k")
kern = RisingFactorial(
-n, k) / (gamma(k + alpha + 1) * factorial(k)) * x**k
return gamma(n + alpha + 1) / factorial(n) * Sum(kern, (k, 0, n))
def _eval_rewrite_as_polynomial(self, n, alpha, x, **kwargs):
# This function is just kept for backwards compatibility
# but should not be used
return self._eval_rewrite_as_Sum(n, alpha, x, **kwargs)
def _eval_conjugate(self):
n, alpha, x = self.args
return self.func(n, alpha.conjugate(), x.conjugate())
PK ]ZZZ�kJ � � 0 sympy/functions/special/singularity_functions.pyfrom sympy.core import S, oo, diff
from sympy.core.function import Function, ArgumentIndexError
from sympy.core.logic import fuzzy_not
from sympy.core.relational import Eq
from sympy.functions.elementary.complexes import im
from sympy.functions.elementary.piecewise import Piecewise
from sympy.functions.special.delta_functions import Heaviside
###############################################################################
############################# SINGULARITY FUNCTION ############################
###############################################################################
class SingularityFunction(Function):
r"""
Singularity functions are a class of discontinuous functions.
Explanation
===========
Singularity functions take a variable, an offset, and an exponent as
arguments. These functions are represented using Macaulay brackets as:
SingularityFunction(x, a, n) := <x - a>^n
The singularity function will automatically evaluate to
``Derivative(DiracDelta(x - a), x, -n - 1)`` if ``n < 0``
and ``(x - a)**n*Heaviside(x - a, 1)`` if ``n >= 0``.
Examples
========
>>> from sympy import SingularityFunction, diff, Piecewise, DiracDelta, Heaviside, Symbol
>>> from sympy.abc import x, a, n
>>> SingularityFunction(x, a, n)
SingularityFunction(x, a, n)
>>> y = Symbol('y', positive=True)
>>> n = Symbol('n', nonnegative=True)
>>> SingularityFunction(y, -10, n)
(y + 10)**n
>>> y = Symbol('y', negative=True)
>>> SingularityFunction(y, 10, n)
0
>>> SingularityFunction(x, 4, -1).subs(x, 4)
oo
>>> SingularityFunction(x, 10, -2).subs(x, 10)
oo
>>> SingularityFunction(4, 1, 5)
243
>>> diff(SingularityFunction(x, 1, 5) + SingularityFunction(x, 1, 4), x)
4*SingularityFunction(x, 1, 3) + 5*SingularityFunction(x, 1, 4)
>>> diff(SingularityFunction(x, 4, 0), x, 2)
SingularityFunction(x, 4, -2)
>>> SingularityFunction(x, 4, 5).rewrite(Piecewise)
Piecewise(((x - 4)**5, x >= 4), (0, True))
>>> expr = SingularityFunction(x, a, n)
>>> y = Symbol('y', positive=True)
>>> n = Symbol('n', nonnegative=True)
>>> expr.subs({x: y, a: -10, n: n})
(y + 10)**n
The methods ``rewrite(DiracDelta)``, ``rewrite(Heaviside)``, and
``rewrite('HeavisideDiracDelta')`` returns the same output. One can use any
of these methods according to their choice.
>>> expr = SingularityFunction(x, 4, 5) + SingularityFunction(x, -3, -1) - SingularityFunction(x, 0, -2)
>>> expr.rewrite(Heaviside)
(x - 4)**5*Heaviside(x - 4, 1) + DiracDelta(x + 3) - DiracDelta(x, 1)
>>> expr.rewrite(DiracDelta)
(x - 4)**5*Heaviside(x - 4, 1) + DiracDelta(x + 3) - DiracDelta(x, 1)
>>> expr.rewrite('HeavisideDiracDelta')
(x - 4)**5*Heaviside(x - 4, 1) + DiracDelta(x + 3) - DiracDelta(x, 1)
See Also
========
DiracDelta, Heaviside
References
==========
.. [1] https://en.wikipedia.org/wiki/Singularity_function
"""
is_real = True
def fdiff(self, argindex=1):
"""
Returns the first derivative of a DiracDelta Function.
Explanation
===========
The difference between ``diff()`` and ``fdiff()`` is: ``diff()`` is the
user-level function and ``fdiff()`` is an object method. ``fdiff()`` is
a convenience method available in the ``Function`` class. It returns
the derivative of the function without considering the chain rule.
``diff(function, x)`` calls ``Function._eval_derivative`` which in turn
calls ``fdiff()`` internally to compute the derivative of the function.
"""
if argindex == 1:
x, a, n = self.args
if n in (S.Zero, S.NegativeOne, S(-2), S(-3)):
return self.func(x, a, n-1)
elif n.is_positive:
return n*self.func(x, a, n-1)
else:
raise ArgumentIndexError(self, argindex)
@classmethod
def eval(cls, variable, offset, exponent):
"""
Returns a simplified form or a value of Singularity Function depending
on the argument passed by the object.
Explanation
===========
The ``eval()`` method is automatically called when the
``SingularityFunction`` class is about to be instantiated and it
returns either some simplified instance or the unevaluated instance
depending on the argument passed. In other words, ``eval()`` method is
not needed to be called explicitly, it is being called and evaluated
once the object is called.
Examples
========
>>> from sympy import SingularityFunction, Symbol, nan
>>> from sympy.abc import x, a, n
>>> SingularityFunction(x, a, n)
SingularityFunction(x, a, n)
>>> SingularityFunction(5, 3, 2)
4
>>> SingularityFunction(x, a, nan)
nan
>>> SingularityFunction(x, 3, 0).subs(x, 3)
1
>>> SingularityFunction(4, 1, 5)
243
>>> x = Symbol('x', positive = True)
>>> a = Symbol('a', negative = True)
>>> n = Symbol('n', nonnegative = True)
>>> SingularityFunction(x, a, n)
(-a + x)**n
>>> x = Symbol('x', negative = True)
>>> a = Symbol('a', positive = True)
>>> SingularityFunction(x, a, n)
0
"""
x = variable
a = offset
n = exponent
shift = (x - a)
if fuzzy_not(im(shift).is_zero):
raise ValueError("Singularity Functions are defined only for Real Numbers.")
if fuzzy_not(im(n).is_zero):
raise ValueError("Singularity Functions are not defined for imaginary exponents.")
if shift is S.NaN or n is S.NaN:
return S.NaN
if (n + 4).is_negative:
raise ValueError("Singularity Functions are not defined for exponents less than -4.")
if shift.is_extended_negative:
return S.Zero
if n.is_nonnegative:
if shift.is_zero: # use literal 0 in case of Symbol('z', zero=True)
return S.Zero**n
if shift.is_extended_nonnegative:
return shift**n
if n in (S.NegativeOne, -2, -3, -4):
if shift.is_negative or shift.is_extended_positive:
return S.Zero
if shift.is_zero:
return oo
def _eval_rewrite_as_Piecewise(self, *args, **kwargs):
'''
Converts a Singularity Function expression into its Piecewise form.
'''
x, a, n = self.args
if n in (S.NegativeOne, S(-2), S(-3), S(-4)):
return Piecewise((oo, Eq(x - a, 0)), (0, True))
elif n.is_nonnegative:
return Piecewise(((x - a)**n, x - a >= 0), (0, True))
def _eval_rewrite_as_Heaviside(self, *args, **kwargs):
'''
Rewrites a Singularity Function expression using Heavisides and DiracDeltas.
'''
x, a, n = self.args
if n == -4:
return diff(Heaviside(x - a), x.free_symbols.pop(), 4)
if n == -3:
return diff(Heaviside(x - a), x.free_symbols.pop(), 3)
if n == -2:
return diff(Heaviside(x - a), x.free_symbols.pop(), 2)
if n == -1:
return diff(Heaviside(x - a), x.free_symbols.pop(), 1)
if n.is_nonnegative:
return (x - a)**n*Heaviside(x - a, 1)
def _eval_as_leading_term(self, x, logx=None, cdir=0):
z, a, n = self.args
shift = (z - a).subs(x, 0)
if n < 0:
return S.Zero
elif n.is_zero and shift.is_zero:
return S.Zero if cdir == -1 else S.One
elif shift.is_positive:
return shift**n
return S.Zero
def _eval_nseries(self, x, n, logx=None, cdir=0):
z, a, n = self.args
shift = (z - a).subs(x, 0)
if n < 0:
return S.Zero
elif n.is_zero and shift.is_zero:
return S.Zero if cdir == -1 else S.One
elif shift.is_positive:
return ((z - a)**n)._eval_nseries(x, n, logx=logx, cdir=cdir)
return S.Zero
_eval_rewrite_as_DiracDelta = _eval_rewrite_as_Heaviside
_eval_rewrite_as_HeavisideDiracDelta = _eval_rewrite_as_Heaviside
PK ]ZZZ����* �* . sympy/functions/special/spherical_harmonics.pyfrom sympy.core.expr import Expr
from sympy.core.function import Function, ArgumentIndexError
from sympy.core.numbers import I, pi
from sympy.core.singleton import S
from sympy.core.symbol import Dummy
from sympy.functions import assoc_legendre
from sympy.functions.combinatorial.factorials import factorial
from sympy.functions.elementary.complexes import Abs, conjugate
from sympy.functions.elementary.exponential import exp
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.elementary.trigonometric import sin, cos, cot
_x = Dummy("x")
class Ynm(Function):
r"""
Spherical harmonics defined as
.. math::
Y_n^m(\theta, \varphi) := \sqrt{\frac{(2n+1)(n-m)!}{4\pi(n+m)!}}
\exp(i m \varphi)
\mathrm{P}_n^m\left(\cos(\theta)\right)
Explanation
===========
``Ynm()`` gives the spherical harmonic function of order $n$ and $m$
in $\theta$ and $\varphi$, $Y_n^m(\theta, \varphi)$. The four
parameters are as follows: $n \geq 0$ an integer and $m$ an integer
such that $-n \leq m \leq n$ holds. The two angles are real-valued
with $\theta \in [0, \pi]$ and $\varphi \in [0, 2\pi]$.
Examples
========
>>> from sympy import Ynm, Symbol, simplify
>>> from sympy.abc import n,m
>>> theta = Symbol("theta")
>>> phi = Symbol("phi")
>>> Ynm(n, m, theta, phi)
Ynm(n, m, theta, phi)
Several symmetries are known, for the order:
>>> Ynm(n, -m, theta, phi)
(-1)**m*exp(-2*I*m*phi)*Ynm(n, m, theta, phi)
As well as for the angles:
>>> Ynm(n, m, -theta, phi)
Ynm(n, m, theta, phi)
>>> Ynm(n, m, theta, -phi)
exp(-2*I*m*phi)*Ynm(n, m, theta, phi)
For specific integers $n$ and $m$ we can evaluate the harmonics
to more useful expressions:
>>> simplify(Ynm(0, 0, theta, phi).expand(func=True))
1/(2*sqrt(pi))
>>> simplify(Ynm(1, -1, theta, phi).expand(func=True))
sqrt(6)*exp(-I*phi)*sin(theta)/(4*sqrt(pi))
>>> simplify(Ynm(1, 0, theta, phi).expand(func=True))
sqrt(3)*cos(theta)/(2*sqrt(pi))
>>> simplify(Ynm(1, 1, theta, phi).expand(func=True))
-sqrt(6)*exp(I*phi)*sin(theta)/(4*sqrt(pi))
>>> simplify(Ynm(2, -2, theta, phi).expand(func=True))
sqrt(30)*exp(-2*I*phi)*sin(theta)**2/(8*sqrt(pi))
>>> simplify(Ynm(2, -1, theta, phi).expand(func=True))
sqrt(30)*exp(-I*phi)*sin(2*theta)/(8*sqrt(pi))
>>> simplify(Ynm(2, 0, theta, phi).expand(func=True))
sqrt(5)*(3*cos(theta)**2 - 1)/(4*sqrt(pi))
>>> simplify(Ynm(2, 1, theta, phi).expand(func=True))
-sqrt(30)*exp(I*phi)*sin(2*theta)/(8*sqrt(pi))
>>> simplify(Ynm(2, 2, theta, phi).expand(func=True))
sqrt(30)*exp(2*I*phi)*sin(theta)**2/(8*sqrt(pi))
We can differentiate the functions with respect
to both angles:
>>> from sympy import Ynm, Symbol, diff
>>> from sympy.abc import n,m
>>> theta = Symbol("theta")
>>> phi = Symbol("phi")
>>> diff(Ynm(n, m, theta, phi), theta)
m*cot(theta)*Ynm(n, m, theta, phi) + sqrt((-m + n)*(m + n + 1))*exp(-I*phi)*Ynm(n, m + 1, theta, phi)
>>> diff(Ynm(n, m, theta, phi), phi)
I*m*Ynm(n, m, theta, phi)
Further we can compute the complex conjugation:
>>> from sympy import Ynm, Symbol, conjugate
>>> from sympy.abc import n,m
>>> theta = Symbol("theta")
>>> phi = Symbol("phi")
>>> conjugate(Ynm(n, m, theta, phi))
(-1)**(2*m)*exp(-2*I*m*phi)*Ynm(n, m, theta, phi)
To get back the well known expressions in spherical
coordinates, we use full expansion:
>>> from sympy import Ynm, Symbol, expand_func
>>> from sympy.abc import n,m
>>> theta = Symbol("theta")
>>> phi = Symbol("phi")
>>> expand_func(Ynm(n, m, theta, phi))
sqrt((2*n + 1)*factorial(-m + n)/factorial(m + n))*exp(I*m*phi)*assoc_legendre(n, m, cos(theta))/(2*sqrt(pi))
See Also
========
Ynm_c, Znm
References
==========
.. [1] https://en.wikipedia.org/wiki/Spherical_harmonics
.. [2] https://mathworld.wolfram.com/SphericalHarmonic.html
.. [3] https://functions.wolfram.com/Polynomials/SphericalHarmonicY/
.. [4] https://dlmf.nist.gov/14.30
"""
@classmethod
def eval(cls, n, m, theta, phi):
# Handle negative index m and arguments theta, phi
if m.could_extract_minus_sign():
m = -m
return S.NegativeOne**m * exp(-2*I*m*phi) * Ynm(n, m, theta, phi)
if theta.could_extract_minus_sign():
theta = -theta
return Ynm(n, m, theta, phi)
if phi.could_extract_minus_sign():
phi = -phi
return exp(-2*I*m*phi) * Ynm(n, m, theta, phi)
# TODO Add more simplififcation here
def _eval_expand_func(self, **hints):
n, m, theta, phi = self.args
rv = (sqrt((2*n + 1)/(4*pi) * factorial(n - m)/factorial(n + m)) *
exp(I*m*phi) * assoc_legendre(n, m, cos(theta)))
# We can do this because of the range of theta
return rv.subs(sqrt(-cos(theta)**2 + 1), sin(theta))
def fdiff(self, argindex=4):
if argindex == 1:
# Diff wrt n
raise ArgumentIndexError(self, argindex)
elif argindex == 2:
# Diff wrt m
raise ArgumentIndexError(self, argindex)
elif argindex == 3:
# Diff wrt theta
n, m, theta, phi = self.args
return (m * cot(theta) * Ynm(n, m, theta, phi) +
sqrt((n - m)*(n + m + 1)) * exp(-I*phi) * Ynm(n, m + 1, theta, phi))
elif argindex == 4:
# Diff wrt phi
n, m, theta, phi = self.args
return I * m * Ynm(n, m, theta, phi)
else:
raise ArgumentIndexError(self, argindex)
def _eval_rewrite_as_polynomial(self, n, m, theta, phi, **kwargs):
# TODO: Make sure n \in N
# TODO: Assert |m| <= n ortherwise we should return 0
return self.expand(func=True)
def _eval_rewrite_as_sin(self, n, m, theta, phi, **kwargs):
return self.rewrite(cos)
def _eval_rewrite_as_cos(self, n, m, theta, phi, **kwargs):
# This method can be expensive due to extensive use of simplification!
from sympy.simplify import simplify, trigsimp
# TODO: Make sure n \in N
# TODO: Assert |m| <= n ortherwise we should return 0
term = simplify(self.expand(func=True))
# We can do this because of the range of theta
term = term.xreplace({Abs(sin(theta)):sin(theta)})
return simplify(trigsimp(term))
def _eval_conjugate(self):
# TODO: Make sure theta \in R and phi \in R
n, m, theta, phi = self.args
return S.NegativeOne**m * self.func(n, -m, theta, phi)
def as_real_imag(self, deep=True, **hints):
# TODO: Handle deep and hints
n, m, theta, phi = self.args
re = (sqrt((2*n + 1)/(4*pi) * factorial(n - m)/factorial(n + m)) *
cos(m*phi) * assoc_legendre(n, m, cos(theta)))
im = (sqrt((2*n + 1)/(4*pi) * factorial(n - m)/factorial(n + m)) *
sin(m*phi) * assoc_legendre(n, m, cos(theta)))
return (re, im)
def _eval_evalf(self, prec):
# Note: works without this function by just calling
# mpmath for Legendre polynomials. But using
# the dedicated function directly is cleaner.
from mpmath import mp, workprec
n = self.args[0]._to_mpmath(prec)
m = self.args[1]._to_mpmath(prec)
theta = self.args[2]._to_mpmath(prec)
phi = self.args[3]._to_mpmath(prec)
with workprec(prec):
res = mp.spherharm(n, m, theta, phi)
return Expr._from_mpmath(res, prec)
def Ynm_c(n, m, theta, phi):
r"""
Conjugate spherical harmonics defined as
.. math::
\overline{Y_n^m(\theta, \varphi)} := (-1)^m Y_n^{-m}(\theta, \varphi).
Examples
========
>>> from sympy import Ynm_c, Symbol, simplify
>>> from sympy.abc import n,m
>>> theta = Symbol("theta")
>>> phi = Symbol("phi")
>>> Ynm_c(n, m, theta, phi)
(-1)**(2*m)*exp(-2*I*m*phi)*Ynm(n, m, theta, phi)
>>> Ynm_c(n, m, -theta, phi)
(-1)**(2*m)*exp(-2*I*m*phi)*Ynm(n, m, theta, phi)
For specific integers $n$ and $m$ we can evaluate the harmonics
to more useful expressions:
>>> simplify(Ynm_c(0, 0, theta, phi).expand(func=True))
1/(2*sqrt(pi))
>>> simplify(Ynm_c(1, -1, theta, phi).expand(func=True))
sqrt(6)*exp(I*(-phi + 2*conjugate(phi)))*sin(theta)/(4*sqrt(pi))
See Also
========
Ynm, Znm
References
==========
.. [1] https://en.wikipedia.org/wiki/Spherical_harmonics
.. [2] https://mathworld.wolfram.com/SphericalHarmonic.html
.. [3] https://functions.wolfram.com/Polynomials/SphericalHarmonicY/
"""
return conjugate(Ynm(n, m, theta, phi))
class Znm(Function):
r"""
Real spherical harmonics defined as
.. math::
Z_n^m(\theta, \varphi) :=
\begin{cases}
\frac{Y_n^m(\theta, \varphi) + \overline{Y_n^m(\theta, \varphi)}}{\sqrt{2}} &\quad m > 0 \\
Y_n^m(\theta, \varphi) &\quad m = 0 \\
\frac{Y_n^m(\theta, \varphi) - \overline{Y_n^m(\theta, \varphi)}}{i \sqrt{2}} &\quad m < 0 \\
\end{cases}
which gives in simplified form
.. math::
Z_n^m(\theta, \varphi) =
\begin{cases}
\frac{Y_n^m(\theta, \varphi) + (-1)^m Y_n^{-m}(\theta, \varphi)}{\sqrt{2}} &\quad m > 0 \\
Y_n^m(\theta, \varphi) &\quad m = 0 \\
\frac{Y_n^m(\theta, \varphi) - (-1)^m Y_n^{-m}(\theta, \varphi)}{i \sqrt{2}} &\quad m < 0 \\
\end{cases}
Examples
========
>>> from sympy import Znm, Symbol, simplify
>>> from sympy.abc import n, m
>>> theta = Symbol("theta")
>>> phi = Symbol("phi")
>>> Znm(n, m, theta, phi)
Znm(n, m, theta, phi)
For specific integers n and m we can evaluate the harmonics
to more useful expressions:
>>> simplify(Znm(0, 0, theta, phi).expand(func=True))
1/(2*sqrt(pi))
>>> simplify(Znm(1, 1, theta, phi).expand(func=True))
-sqrt(3)*sin(theta)*cos(phi)/(2*sqrt(pi))
>>> simplify(Znm(2, 1, theta, phi).expand(func=True))
-sqrt(15)*sin(2*theta)*cos(phi)/(4*sqrt(pi))
See Also
========
Ynm, Ynm_c
References
==========
.. [1] https://en.wikipedia.org/wiki/Spherical_harmonics
.. [2] https://mathworld.wolfram.com/SphericalHarmonic.html
.. [3] https://functions.wolfram.com/Polynomials/SphericalHarmonicY/
"""
@classmethod
def eval(cls, n, m, theta, phi):
if m.is_positive:
zz = (Ynm(n, m, theta, phi) + Ynm_c(n, m, theta, phi)) / sqrt(2)
return zz
elif m.is_zero:
return Ynm(n, m, theta, phi)
elif m.is_negative:
zz = (Ynm(n, m, theta, phi) - Ynm_c(n, m, theta, phi)) / (sqrt(2)*I)
return zz
PK ]ZZZ�����/ �/ + sympy/functions/special/tensor_functions.pyfrom math import prod
from sympy.core import S, Integer
from sympy.core.function import Function
from sympy.core.logic import fuzzy_not
from sympy.core.relational import Ne
from sympy.core.sorting import default_sort_key
from sympy.external.gmpy import SYMPY_INTS
from sympy.functions.combinatorial.factorials import factorial
from sympy.functions.elementary.piecewise import Piecewise
from sympy.utilities.iterables import has_dups
###############################################################################
###################### Kronecker Delta, Levi-Civita etc. ######################
###############################################################################
def Eijk(*args, **kwargs):
"""
Represent the Levi-Civita symbol.
This is a compatibility wrapper to ``LeviCivita()``.
See Also
========
LeviCivita
"""
return LeviCivita(*args, **kwargs)
def eval_levicivita(*args):
"""Evaluate Levi-Civita symbol."""
n = len(args)
return prod(
prod(args[j] - args[i] for j in range(i + 1, n))
/ factorial(i) for i in range(n))
# converting factorial(i) to int is slightly faster
class LeviCivita(Function):
"""
Represent the Levi-Civita symbol.
Explanation
===========
For even permutations of indices it returns 1, for odd permutations -1, and
for everything else (a repeated index) it returns 0.
Thus it represents an alternating pseudotensor.
Examples
========
>>> from sympy import LeviCivita
>>> from sympy.abc import i, j, k
>>> LeviCivita(1, 2, 3)
1
>>> LeviCivita(1, 3, 2)
-1
>>> LeviCivita(1, 2, 2)
0
>>> LeviCivita(i, j, k)
LeviCivita(i, j, k)
>>> LeviCivita(i, j, i)
0
See Also
========
Eijk
"""
is_integer = True
@classmethod
def eval(cls, *args):
if all(isinstance(a, (SYMPY_INTS, Integer)) for a in args):
return eval_levicivita(*args)
if has_dups(args):
return S.Zero
def doit(self, **hints):
return eval_levicivita(*self.args)
class KroneckerDelta(Function):
"""
The discrete, or Kronecker, delta function.
Explanation
===========
A function that takes in two integers $i$ and $j$. It returns $0$ if $i$
and $j$ are not equal, or it returns $1$ if $i$ and $j$ are equal.
Examples
========
An example with integer indices:
>>> from sympy import KroneckerDelta
>>> KroneckerDelta(1, 2)
0
>>> KroneckerDelta(3, 3)
1
Symbolic indices:
>>> from sympy.abc import i, j, k
>>> KroneckerDelta(i, j)
KroneckerDelta(i, j)
>>> KroneckerDelta(i, i)
1
>>> KroneckerDelta(i, i + 1)
0
>>> KroneckerDelta(i, i + 1 + k)
KroneckerDelta(i, i + k + 1)
Parameters
==========
i : Number, Symbol
The first index of the delta function.
j : Number, Symbol
The second index of the delta function.
See Also
========
eval
DiracDelta
References
==========
.. [1] https://en.wikipedia.org/wiki/Kronecker_delta
"""
is_integer = True
@classmethod
def eval(cls, i, j, delta_range=None):
"""
Evaluates the discrete delta function.
Examples
========
>>> from sympy import KroneckerDelta
>>> from sympy.abc import i, j, k
>>> KroneckerDelta(i, j)
KroneckerDelta(i, j)
>>> KroneckerDelta(i, i)
1
>>> KroneckerDelta(i, i + 1)
0
>>> KroneckerDelta(i, i + 1 + k)
KroneckerDelta(i, i + k + 1)
# indirect doctest
"""
if delta_range is not None:
dinf, dsup = delta_range
if (dinf - i > 0) == True:
return S.Zero
if (dinf - j > 0) == True:
return S.Zero
if (dsup - i < 0) == True:
return S.Zero
if (dsup - j < 0) == True:
return S.Zero
diff = i - j
if diff.is_zero:
return S.One
elif fuzzy_not(diff.is_zero):
return S.Zero
if i.assumptions0.get("below_fermi") and \
j.assumptions0.get("above_fermi"):
return S.Zero
if j.assumptions0.get("below_fermi") and \
i.assumptions0.get("above_fermi"):
return S.Zero
# to make KroneckerDelta canonical
# following lines will check if inputs are in order
# if not, will return KroneckerDelta with correct order
if default_sort_key(j) < default_sort_key(i):
if delta_range:
return cls(j, i, delta_range)
else:
return cls(j, i)
@property
def delta_range(self):
if len(self.args) > 2:
return self.args[2]
def _eval_power(self, expt):
if expt.is_positive:
return self
if expt.is_negative and expt is not S.NegativeOne:
return 1/self
@property
def is_above_fermi(self):
"""
True if Delta can be non-zero above fermi.
Examples
========
>>> from sympy import KroneckerDelta, Symbol
>>> a = Symbol('a', above_fermi=True)
>>> i = Symbol('i', below_fermi=True)
>>> p = Symbol('p')
>>> q = Symbol('q')
>>> KroneckerDelta(p, a).is_above_fermi
True
>>> KroneckerDelta(p, i).is_above_fermi
False
>>> KroneckerDelta(p, q).is_above_fermi
True
See Also
========
is_below_fermi, is_only_below_fermi, is_only_above_fermi
"""
if self.args[0].assumptions0.get("below_fermi"):
return False
if self.args[1].assumptions0.get("below_fermi"):
return False
return True
@property
def is_below_fermi(self):
"""
True if Delta can be non-zero below fermi.
Examples
========
>>> from sympy import KroneckerDelta, Symbol
>>> a = Symbol('a', above_fermi=True)
>>> i = Symbol('i', below_fermi=True)
>>> p = Symbol('p')
>>> q = Symbol('q')
>>> KroneckerDelta(p, a).is_below_fermi
False
>>> KroneckerDelta(p, i).is_below_fermi
True
>>> KroneckerDelta(p, q).is_below_fermi
True
See Also
========
is_above_fermi, is_only_above_fermi, is_only_below_fermi
"""
if self.args[0].assumptions0.get("above_fermi"):
return False
if self.args[1].assumptions0.get("above_fermi"):
return False
return True
@property
def is_only_above_fermi(self):
"""
True if Delta is restricted to above fermi.
Examples
========
>>> from sympy import KroneckerDelta, Symbol
>>> a = Symbol('a', above_fermi=True)
>>> i = Symbol('i', below_fermi=True)
>>> p = Symbol('p')
>>> q = Symbol('q')
>>> KroneckerDelta(p, a).is_only_above_fermi
True
>>> KroneckerDelta(p, q).is_only_above_fermi
False
>>> KroneckerDelta(p, i).is_only_above_fermi
False
See Also
========
is_above_fermi, is_below_fermi, is_only_below_fermi
"""
return ( self.args[0].assumptions0.get("above_fermi")
or
self.args[1].assumptions0.get("above_fermi")
) or False
@property
def is_only_below_fermi(self):
"""
True if Delta is restricted to below fermi.
Examples
========
>>> from sympy import KroneckerDelta, Symbol
>>> a = Symbol('a', above_fermi=True)
>>> i = Symbol('i', below_fermi=True)
>>> p = Symbol('p')
>>> q = Symbol('q')
>>> KroneckerDelta(p, i).is_only_below_fermi
True
>>> KroneckerDelta(p, q).is_only_below_fermi
False
>>> KroneckerDelta(p, a).is_only_below_fermi
False
See Also
========
is_above_fermi, is_below_fermi, is_only_above_fermi
"""
return ( self.args[0].assumptions0.get("below_fermi")
or
self.args[1].assumptions0.get("below_fermi")
) or False
@property
def indices_contain_equal_information(self):
"""
Returns True if indices are either both above or below fermi.
Examples
========
>>> from sympy import KroneckerDelta, Symbol
>>> a = Symbol('a', above_fermi=True)
>>> i = Symbol('i', below_fermi=True)
>>> p = Symbol('p')
>>> q = Symbol('q')
>>> KroneckerDelta(p, q).indices_contain_equal_information
True
>>> KroneckerDelta(p, q+1).indices_contain_equal_information
True
>>> KroneckerDelta(i, p).indices_contain_equal_information
False
"""
if (self.args[0].assumptions0.get("below_fermi") and
self.args[1].assumptions0.get("below_fermi")):
return True
if (self.args[0].assumptions0.get("above_fermi")
and self.args[1].assumptions0.get("above_fermi")):
return True
# if both indices are general we are True, else false
return self.is_below_fermi and self.is_above_fermi
@property
def preferred_index(self):
"""
Returns the index which is preferred to keep in the final expression.
Explanation
===========
The preferred index is the index with more information regarding fermi
level. If indices contain the same information, 'a' is preferred before
'b'.
Examples
========
>>> from sympy import KroneckerDelta, Symbol
>>> a = Symbol('a', above_fermi=True)
>>> i = Symbol('i', below_fermi=True)
>>> j = Symbol('j', below_fermi=True)
>>> p = Symbol('p')
>>> KroneckerDelta(p, i).preferred_index
i
>>> KroneckerDelta(p, a).preferred_index
a
>>> KroneckerDelta(i, j).preferred_index
i
See Also
========
killable_index
"""
if self._get_preferred_index():
return self.args[1]
else:
return self.args[0]
@property
def killable_index(self):
"""
Returns the index which is preferred to substitute in the final
expression.
Explanation
===========
The index to substitute is the index with less information regarding
fermi level. If indices contain the same information, 'a' is preferred
before 'b'.
Examples
========
>>> from sympy import KroneckerDelta, Symbol
>>> a = Symbol('a', above_fermi=True)
>>> i = Symbol('i', below_fermi=True)
>>> j = Symbol('j', below_fermi=True)
>>> p = Symbol('p')
>>> KroneckerDelta(p, i).killable_index
p
>>> KroneckerDelta(p, a).killable_index
p
>>> KroneckerDelta(i, j).killable_index
j
See Also
========
preferred_index
"""
if self._get_preferred_index():
return self.args[0]
else:
return self.args[1]
def _get_preferred_index(self):
"""
Returns the index which is preferred to keep in the final expression.
The preferred index is the index with more information regarding fermi
level. If indices contain the same information, index 0 is returned.
"""
if not self.is_above_fermi:
if self.args[0].assumptions0.get("below_fermi"):
return 0
else:
return 1
elif not self.is_below_fermi:
if self.args[0].assumptions0.get("above_fermi"):
return 0
else:
return 1
else:
return 0
@property
def indices(self):
return self.args[0:2]
def _eval_rewrite_as_Piecewise(self, *args, **kwargs):
i, j = args
return Piecewise((0, Ne(i, j)), (1, True))
PK ]ZZZk��: ^ ^ ) sympy/functions/special/zeta_functions.py""" Riemann zeta and related function. """
from sympy.core.add import Add
from sympy.core.cache import cacheit
from sympy.core.function import ArgumentIndexError, expand_mul, Function
from sympy.core.numbers import pi, I, Integer
from sympy.core.relational import Eq
from sympy.core.singleton import S
from sympy.core.symbol import Dummy
from sympy.core.sympify import sympify
from sympy.functions.combinatorial.numbers import bernoulli, factorial, genocchi, harmonic
from sympy.functions.elementary.complexes import re, unpolarify, Abs, polar_lift
from sympy.functions.elementary.exponential import log, exp_polar, exp
from sympy.functions.elementary.integers import ceiling, floor
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.elementary.piecewise import Piecewise
from sympy.polys.polytools import Poly
###############################################################################
###################### LERCH TRANSCENDENT #####################################
###############################################################################
class lerchphi(Function):
r"""
Lerch transcendent (Lerch phi function).
Explanation
===========
For $\operatorname{Re}(a) > 0$, $|z| < 1$ and $s \in \mathbb{C}$, the
Lerch transcendent is defined as
.. math :: \Phi(z, s, a) = \sum_{n=0}^\infty \frac{z^n}{(n + a)^s},
where the standard branch of the argument is used for $n + a$,
and by analytic continuation for other values of the parameters.
A commonly used related function is the Lerch zeta function, defined by
.. math:: L(q, s, a) = \Phi(e^{2\pi i q}, s, a).
**Analytic Continuation and Branching Behavior**
It can be shown that
.. math:: \Phi(z, s, a) = z\Phi(z, s, a+1) + a^{-s}.
This provides the analytic continuation to $\operatorname{Re}(a) \le 0$.
Assume now $\operatorname{Re}(a) > 0$. The integral representation
.. math:: \Phi_0(z, s, a) = \int_0^\infty \frac{t^{s-1} e^{-at}}{1 - ze^{-t}}
\frac{\mathrm{d}t}{\Gamma(s)}
provides an analytic continuation to $\mathbb{C} - [1, \infty)$.
Finally, for $x \in (1, \infty)$ we find
.. math:: \lim_{\epsilon \to 0^+} \Phi_0(x + i\epsilon, s, a)
-\lim_{\epsilon \to 0^+} \Phi_0(x - i\epsilon, s, a)
= \frac{2\pi i \log^{s-1}{x}}{x^a \Gamma(s)},
using the standard branch for both $\log{x}$ and
$\log{\log{x}}$ (a branch of $\log{\log{x}}$ is needed to
evaluate $\log{x}^{s-1}$).
This concludes the analytic continuation. The Lerch transcendent is thus
branched at $z \in \{0, 1, \infty\}$ and
$a \in \mathbb{Z}_{\le 0}$. For fixed $z, a$ outside these
branch points, it is an entire function of $s$.
Examples
========
The Lerch transcendent is a fairly general function, for this reason it does
not automatically evaluate to simpler functions. Use ``expand_func()`` to
achieve this.
If $z=1$, the Lerch transcendent reduces to the Hurwitz zeta function:
>>> from sympy import lerchphi, expand_func
>>> from sympy.abc import z, s, a
>>> expand_func(lerchphi(1, s, a))
zeta(s, a)
More generally, if $z$ is a root of unity, the Lerch transcendent
reduces to a sum of Hurwitz zeta functions:
>>> expand_func(lerchphi(-1, s, a))
zeta(s, a/2)/2**s - zeta(s, a/2 + 1/2)/2**s
If $a=1$, the Lerch transcendent reduces to the polylogarithm:
>>> expand_func(lerchphi(z, s, 1))
polylog(s, z)/z
More generally, if $a$ is rational, the Lerch transcendent reduces
to a sum of polylogarithms:
>>> from sympy import S
>>> expand_func(lerchphi(z, s, S(1)/2))
2**(s - 1)*(polylog(s, sqrt(z))/sqrt(z) -
polylog(s, sqrt(z)*exp_polar(I*pi))/sqrt(z))
>>> expand_func(lerchphi(z, s, S(3)/2))
-2**s/z + 2**(s - 1)*(polylog(s, sqrt(z))/sqrt(z) -
polylog(s, sqrt(z)*exp_polar(I*pi))/sqrt(z))/z
The derivatives with respect to $z$ and $a$ can be computed in
closed form:
>>> lerchphi(z, s, a).diff(z)
(-a*lerchphi(z, s, a) + lerchphi(z, s - 1, a))/z
>>> lerchphi(z, s, a).diff(a)
-s*lerchphi(z, s + 1, a)
See Also
========
polylog, zeta
References
==========
.. [1] Bateman, H.; Erdelyi, A. (1953), Higher Transcendental Functions,
Vol. I, New York: McGraw-Hill. Section 1.11.
.. [2] https://dlmf.nist.gov/25.14
.. [3] https://en.wikipedia.org/wiki/Lerch_transcendent
"""
def _eval_expand_func(self, **hints):
z, s, a = self.args
if z == 1:
return zeta(s, a)
if s.is_Integer and s <= 0:
t = Dummy('t')
p = Poly((t + a)**(-s), t)
start = 1/(1 - t)
res = S.Zero
for c in reversed(p.all_coeffs()):
res += c*start
start = t*start.diff(t)
return res.subs(t, z)
if a.is_Rational:
# See section 18 of
# Kelly B. Roach. Hypergeometric Function Representations.
# In: Proceedings of the 1997 International Symposium on Symbolic and
# Algebraic Computation, pages 205-211, New York, 1997. ACM.
# TODO should something be polarified here?
add = S.Zero
mul = S.One
# First reduce a to the interaval (0, 1]
if a > 1:
n = floor(a)
if n == a:
n -= 1
a -= n
mul = z**(-n)
add = Add(*[-z**(k - n)/(a + k)**s for k in range(n)])
elif a <= 0:
n = floor(-a) + 1
a += n
mul = z**n
add = Add(*[z**(n - 1 - k)/(a - k - 1)**s for k in range(n)])
m, n = S([a.p, a.q])
zet = exp_polar(2*pi*I/n)
root = z**(1/n)
up_zet = unpolarify(zet)
addargs = []
for k in range(n):
p = polylog(s, zet**k*root)
if isinstance(p, polylog):
p = p._eval_expand_func(**hints)
addargs.append(p/(up_zet**k*root)**m)
return add + mul*n**(s - 1)*Add(*addargs)
# TODO use minpoly instead of ad-hoc methods when issue 5888 is fixed
if isinstance(z, exp) and (z.args[0]/(pi*I)).is_Rational or z in [-1, I, -I]:
# TODO reference?
if z == -1:
p, q = S([1, 2])
elif z == I:
p, q = S([1, 4])
elif z == -I:
p, q = S([-1, 4])
else:
arg = z.args[0]/(2*pi*I)
p, q = S([arg.p, arg.q])
return Add(*[exp(2*pi*I*k*p/q)/q**s*zeta(s, (k + a)/q)
for k in range(q)])
return lerchphi(z, s, a)
def fdiff(self, argindex=1):
z, s, a = self.args
if argindex == 3:
return -s*lerchphi(z, s + 1, a)
elif argindex == 1:
return (lerchphi(z, s - 1, a) - a*lerchphi(z, s, a))/z
else:
raise ArgumentIndexError
def _eval_rewrite_helper(self, target):
res = self._eval_expand_func()
if res.has(target):
return res
else:
return self
def _eval_rewrite_as_zeta(self, z, s, a, **kwargs):
return self._eval_rewrite_helper(zeta)
def _eval_rewrite_as_polylog(self, z, s, a, **kwargs):
return self._eval_rewrite_helper(polylog)
###############################################################################
###################### POLYLOGARITHM ##########################################
###############################################################################
class polylog(Function):
r"""
Polylogarithm function.
Explanation
===========
For $|z| < 1$ and $s \in \mathbb{C}$, the polylogarithm is
defined by
.. math:: \operatorname{Li}_s(z) = \sum_{n=1}^\infty \frac{z^n}{n^s},
where the standard branch of the argument is used for $n$. It admits
an analytic continuation which is branched at $z=1$ (notably not on the
sheet of initial definition), $z=0$ and $z=\infty$.
The name polylogarithm comes from the fact that for $s=1$, the
polylogarithm is related to the ordinary logarithm (see examples), and that
.. math:: \operatorname{Li}_{s+1}(z) =
\int_0^z \frac{\operatorname{Li}_s(t)}{t} \mathrm{d}t.
The polylogarithm is a special case of the Lerch transcendent:
.. math:: \operatorname{Li}_{s}(z) = z \Phi(z, s, 1).
Examples
========
For $z \in \{0, 1, -1\}$, the polylogarithm is automatically expressed
using other functions:
>>> from sympy import polylog
>>> from sympy.abc import s
>>> polylog(s, 0)
0
>>> polylog(s, 1)
zeta(s)
>>> polylog(s, -1)
-dirichlet_eta(s)
If $s$ is a negative integer, $0$ or $1$, the polylogarithm can be
expressed using elementary functions. This can be done using
``expand_func()``:
>>> from sympy import expand_func
>>> from sympy.abc import z
>>> expand_func(polylog(1, z))
-log(1 - z)
>>> expand_func(polylog(0, z))
z/(1 - z)
The derivative with respect to $z$ can be computed in closed form:
>>> polylog(s, z).diff(z)
polylog(s - 1, z)/z
The polylogarithm can be expressed in terms of the lerch transcendent:
>>> from sympy import lerchphi
>>> polylog(s, z).rewrite(lerchphi)
z*lerchphi(z, s, 1)
See Also
========
zeta, lerchphi
"""
@classmethod
def eval(cls, s, z):
if z.is_number:
if z is S.One:
return zeta(s)
elif z is S.NegativeOne:
return -dirichlet_eta(s)
elif z is S.Zero:
return S.Zero
elif s == 2:
dilogtable = _dilogtable()
if z in dilogtable:
return dilogtable[z]
if z.is_zero:
return S.Zero
# Make an effort to determine if z is 1 to avoid replacing into
# expression with singularity
zone = z.equals(S.One)
if zone:
return zeta(s)
elif zone is False:
# For s = 0 or -1 use explicit formulas to evaluate, but
# automatically expanding polylog(1, z) to -log(1-z) seems
# undesirable for summation methods based on hypergeometric
# functions
if s is S.Zero:
return z/(1 - z)
elif s is S.NegativeOne:
return z/(1 - z)**2
if s.is_zero:
return z/(1 - z)
# polylog is branched, but not over the unit disk
if z.has(exp_polar, polar_lift) and (zone or (Abs(z) <= S.One) == True):
return cls(s, unpolarify(z))
def fdiff(self, argindex=1):
s, z = self.args
if argindex == 2:
return polylog(s - 1, z)/z
raise ArgumentIndexError
def _eval_rewrite_as_lerchphi(self, s, z, **kwargs):
return z*lerchphi(z, s, 1)
def _eval_expand_func(self, **hints):
s, z = self.args
if s == 1:
return -log(1 - z)
if s.is_Integer and s <= 0:
u = Dummy('u')
start = u/(1 - u)
for _ in range(-s):
start = u*start.diff(u)
return expand_mul(start).subs(u, z)
return polylog(s, z)
def _eval_is_zero(self):
z = self.args[1]
if z.is_zero:
return True
def _eval_nseries(self, x, n, logx, cdir=0):
from sympy.series.order import Order
nu, z = self.args
z0 = z.subs(x, 0)
if z0 is S.NaN:
z0 = z.limit(x, 0, dir='-' if re(cdir).is_negative else '+')
if z0.is_zero:
# In case of powers less than 1, number of terms need to be computed
# separately to avoid repeated callings of _eval_nseries with wrong n
try:
_, exp = z.leadterm(x)
except (ValueError, NotImplementedError):
return self
if exp.is_positive:
newn = ceiling(n/exp)
o = Order(x**n, x)
r = z._eval_nseries(x, n, logx, cdir).removeO()
if r is S.Zero:
return o
term = r
s = [term]
for k in range(2, newn):
term *= r
s.append(term/k**nu)
return Add(*s) + o
return super(polylog, self)._eval_nseries(x, n, logx, cdir)
###############################################################################
###################### HURWITZ GENERALIZED ZETA FUNCTION ######################
###############################################################################
class zeta(Function):
r"""
Hurwitz zeta function (or Riemann zeta function).
Explanation
===========
For $\operatorname{Re}(a) > 0$ and $\operatorname{Re}(s) > 1$, this
function is defined as
.. math:: \zeta(s, a) = \sum_{n=0}^\infty \frac{1}{(n + a)^s},
where the standard choice of argument for $n + a$ is used. For fixed
$a$ not a nonpositive integer the Hurwitz zeta function admits a
meromorphic continuation to all of $\mathbb{C}$; it is an unbranched
function with a simple pole at $s = 1$.
The Hurwitz zeta function is a special case of the Lerch transcendent:
.. math:: \zeta(s, a) = \Phi(1, s, a).
This formula defines an analytic continuation for all possible values of
$s$ and $a$ (also $\operatorname{Re}(a) < 0$), see the documentation of
:class:`lerchphi` for a description of the branching behavior.
If no value is passed for $a$ a default value of $a = 1$ is assumed,
yielding the Riemann zeta function.
Examples
========
For $a = 1$ the Hurwitz zeta function reduces to the famous Riemann
zeta function:
.. math:: \zeta(s, 1) = \zeta(s) = \sum_{n=1}^\infty \frac{1}{n^s}.
>>> from sympy import zeta
>>> from sympy.abc import s
>>> zeta(s, 1)
zeta(s)
>>> zeta(s)
zeta(s)
The Riemann zeta function can also be expressed using the Dirichlet eta
function:
>>> from sympy import dirichlet_eta
>>> zeta(s).rewrite(dirichlet_eta)
dirichlet_eta(s)/(1 - 2**(1 - s))
The Riemann zeta function at nonnegative even and negative integer
values is related to the Bernoulli numbers and polynomials:
>>> zeta(2)
pi**2/6
>>> zeta(4)
pi**4/90
>>> zeta(0)
-1/2
>>> zeta(-1)
-1/12
>>> zeta(-4)
0
The specific formulae are:
.. math:: \zeta(2n) = -\frac{(2\pi i)^{2n} B_{2n}}{2(2n)!}
.. math:: \zeta(-n,a) = -\frac{B_{n+1}(a)}{n+1}
No closed-form expressions are known at positive odd integers, but
numerical evaluation is possible:
>>> zeta(3).n()
1.20205690315959
The derivative of $\zeta(s, a)$ with respect to $a$ can be computed:
>>> from sympy.abc import a
>>> zeta(s, a).diff(a)
-s*zeta(s + 1, a)
However the derivative with respect to $s$ has no useful closed form
expression:
>>> zeta(s, a).diff(s)
Derivative(zeta(s, a), s)
The Hurwitz zeta function can be expressed in terms of the Lerch
transcendent, :class:`~.lerchphi`:
>>> from sympy import lerchphi
>>> zeta(s, a).rewrite(lerchphi)
lerchphi(1, s, a)
See Also
========
dirichlet_eta, lerchphi, polylog
References
==========
.. [1] https://dlmf.nist.gov/25.11
.. [2] https://en.wikipedia.org/wiki/Hurwitz_zeta_function
"""
@classmethod
def eval(cls, s, a=None):
if a is S.One:
return cls(s)
elif s is S.NaN or a is S.NaN:
return S.NaN
elif s is S.One:
return S.ComplexInfinity
elif s is S.Infinity:
return S.One
elif a is S.Infinity:
return S.Zero
sint = s.is_Integer
if a is None:
a = S.One
if sint and s.is_nonpositive:
return bernoulli(1-s, a) / (s-1)
elif a is S.One:
if sint and s.is_even:
return -(2*pi*I)**s * bernoulli(s) / (2*factorial(s))
elif sint and a.is_Integer and a.is_positive:
return cls(s) - harmonic(a-1, s)
elif a.is_Integer and a.is_nonpositive and \
(s.is_integer is False or s.is_nonpositive is False):
return S.NaN
def _eval_rewrite_as_bernoulli(self, s, a=1, **kwargs):
if a == 1 and s.is_integer and s.is_nonnegative and s.is_even:
return -(2*pi*I)**s * bernoulli(s) / (2*factorial(s))
return bernoulli(1-s, a) / (s-1)
def _eval_rewrite_as_dirichlet_eta(self, s, a=1, **kwargs):
if a != 1:
return self
s = self.args[0]
return dirichlet_eta(s)/(1 - 2**(1 - s))
def _eval_rewrite_as_lerchphi(self, s, a=1, **kwargs):
return lerchphi(1, s, a)
def _eval_is_finite(self):
arg_is_one = (self.args[0] - 1).is_zero
if arg_is_one is not None:
return not arg_is_one
def _eval_expand_func(self, **hints):
s = self.args[0]
a = self.args[1] if len(self.args) > 1 else S.One
if a.is_integer:
if a.is_positive:
return zeta(s) - harmonic(a-1, s)
if a.is_nonpositive and (s.is_integer is False or
s.is_nonpositive is False):
return S.NaN
return self
def fdiff(self, argindex=1):
if len(self.args) == 2:
s, a = self.args
else:
s, a = self.args + (1,)
if argindex == 2:
return -s*zeta(s + 1, a)
else:
raise ArgumentIndexError
def _eval_as_leading_term(self, x, logx=None, cdir=0):
if len(self.args) == 2:
s, a = self.args
else:
s, a = self.args + (S.One,)
try:
c, e = a.leadterm(x)
except NotImplementedError:
return self
if e.is_negative and not s.is_positive:
raise NotImplementedError
return super(zeta, self)._eval_as_leading_term(x, logx, cdir)
class dirichlet_eta(Function):
r"""
Dirichlet eta function.
Explanation
===========
For $\operatorname{Re}(s) > 0$ and $0 < x \le 1$, this function is defined as
.. math:: \eta(s, a) = \sum_{n=0}^\infty \frac{(-1)^n}{(n+a)^s}.
It admits a unique analytic continuation to all of $\mathbb{C}$ for any
fixed $a$ not a nonpositive integer. It is an entire, unbranched function.
It can be expressed using the Hurwitz zeta function as
.. math:: \eta(s, a) = \zeta(s,a) - 2^{1-s} \zeta\left(s, \frac{a+1}{2}\right)
and using the generalized Genocchi function as
.. math:: \eta(s, a) = \frac{G(1-s, a)}{2(s-1)}.
In both cases the limiting value of $\log2 - \psi(a) + \psi\left(\frac{a+1}{2}\right)$
is used when $s = 1$.
Examples
========
>>> from sympy import dirichlet_eta, zeta
>>> from sympy.abc import s
>>> dirichlet_eta(s).rewrite(zeta)
Piecewise((log(2), Eq(s, 1)), ((1 - 2**(1 - s))*zeta(s), True))
See Also
========
zeta
References
==========
.. [1] https://en.wikipedia.org/wiki/Dirichlet_eta_function
.. [2] Peter Luschny, "An introduction to the Bernoulli function",
https://arxiv.org/abs/2009.06743
"""
@classmethod
def eval(cls, s, a=None):
if a is S.One:
return cls(s)
if a is None:
if s == 1:
return log(2)
z = zeta(s)
if not z.has(zeta):
return (1 - 2**(1-s)) * z
return
elif s == 1:
from sympy.functions.special.gamma_functions import digamma
return log(2) - digamma(a) + digamma((a+1)/2)
z1 = zeta(s, a)
z2 = zeta(s, (a+1)/2)
if not z1.has(zeta) and not z2.has(zeta):
return z1 - 2**(1-s) * z2
def _eval_rewrite_as_zeta(self, s, a=1, **kwargs):
from sympy.functions.special.gamma_functions import digamma
if a == 1:
return Piecewise((log(2), Eq(s, 1)), ((1 - 2**(1-s)) * zeta(s), True))
return Piecewise((log(2) - digamma(a) + digamma((a+1)/2), Eq(s, 1)),
(zeta(s, a) - 2**(1-s) * zeta(s, (a+1)/2), True))
def _eval_rewrite_as_genocchi(self, s, a=S.One, **kwargs):
from sympy.functions.special.gamma_functions import digamma
return Piecewise((log(2) - digamma(a) + digamma((a+1)/2), Eq(s, 1)),
(genocchi(1-s, a) / (2 * (s-1)), True))
def _eval_evalf(self, prec):
if all(i.is_number for i in self.args):
return self.rewrite(zeta)._eval_evalf(prec)
class riemann_xi(Function):
r"""
Riemann Xi function.
Examples
========
The Riemann Xi function is closely related to the Riemann zeta function.
The zeros of Riemann Xi function are precisely the non-trivial zeros
of the zeta function.
>>> from sympy import riemann_xi, zeta
>>> from sympy.abc import s
>>> riemann_xi(s).rewrite(zeta)
s*(s - 1)*gamma(s/2)*zeta(s)/(2*pi**(s/2))
References
==========
.. [1] https://en.wikipedia.org/wiki/Riemann_Xi_function
"""
@classmethod
def eval(cls, s):
from sympy.functions.special.gamma_functions import gamma
z = zeta(s)
if s in (S.Zero, S.One):
return S.Half
if not isinstance(z, zeta):
return s*(s - 1)*gamma(s/2)*z/(2*pi**(s/2))
def _eval_rewrite_as_zeta(self, s, **kwargs):
from sympy.functions.special.gamma_functions import gamma
return s*(s - 1)*gamma(s/2)*zeta(s)/(2*pi**(s/2))
class stieltjes(Function):
r"""
Represents Stieltjes constants, $\gamma_{k}$ that occur in
Laurent Series expansion of the Riemann zeta function.
Examples
========
>>> from sympy import stieltjes
>>> from sympy.abc import n, m
>>> stieltjes(n)
stieltjes(n)
The zero'th stieltjes constant:
>>> stieltjes(0)
EulerGamma
>>> stieltjes(0, 1)
EulerGamma
For generalized stieltjes constants:
>>> stieltjes(n, m)
stieltjes(n, m)
Constants are only defined for integers >= 0:
>>> stieltjes(-1)
zoo
References
==========
.. [1] https://en.wikipedia.org/wiki/Stieltjes_constants
"""
@classmethod
def eval(cls, n, a=None):
if a is not None:
a = sympify(a)
if a is S.NaN:
return S.NaN
if a.is_Integer and a.is_nonpositive:
return S.ComplexInfinity
if n.is_Number:
if n is S.NaN:
return S.NaN
elif n < 0:
return S.ComplexInfinity
elif not n.is_Integer:
return S.ComplexInfinity
elif n is S.Zero and a in [None, 1]:
return S.EulerGamma
if n.is_extended_negative:
return S.ComplexInfinity
if n.is_zero and a in [None, 1]:
return S.EulerGamma
if n.is_integer == False:
return S.ComplexInfinity
@cacheit
def _dilogtable():
return {
S.Half: pi**2/12 - log(2)**2/2,
Integer(2) : pi**2/4 - I*pi*log(2),
-(sqrt(5) - 1)/2 : -pi**2/15 + log((sqrt(5)-1)/2)**2/2,
-(sqrt(5) + 1)/2 : -pi**2/10 - log((sqrt(5)+1)/2)**2,
(3 - sqrt(5))/2 : pi**2/15 - log((sqrt(5)-1)/2)**2,
(sqrt(5) - 1)/2 : pi**2/10 - log((sqrt(5)-1)/2)**2,
I : I*S.Catalan - pi**2/48,
-I : -I*S.Catalan - pi**2/48,
1 - I : pi**2/16 - I*S.Catalan - pi*I/4*log(2),
1 + I : pi**2/16 + I*S.Catalan + pi*I/4*log(2),
(1 - I)/2 : -log(2)**2/8 + pi*I*log(2)/8 + 5*pi**2/96 - I*S.Catalan
}
PK ]ZZZ . sympy/functions/special/benchmarks/__init__.pyPK ]ZZZ��\� � 3 sympy/functions/special/benchmarks/bench_special.pyfrom sympy.core.symbol import symbols
from sympy.functions.special.spherical_harmonics import Ynm
x, y = symbols('x,y')
def timeit_Ynm_xy():
Ynm(1, 1, x, y)
PK ]ZZZ���V� � sympy/geometry/__init__.py"""
A geometry module for the SymPy library. This module contains all of the
entities and functions needed to construct basic geometrical data and to
perform simple informational queries.
Usage:
======
Examples
========
"""
from sympy.geometry.point import Point, Point2D, Point3D
from sympy.geometry.line import Line, Ray, Segment, Line2D, Segment2D, Ray2D, \
Line3D, Segment3D, Ray3D
from sympy.geometry.plane import Plane
from sympy.geometry.ellipse import Ellipse, Circle
from sympy.geometry.polygon import Polygon, RegularPolygon, Triangle, rad, deg
from sympy.geometry.util import are_similar, centroid, convex_hull, idiff, \
intersection, closest_points, farthest_points
from sympy.geometry.exceptions import GeometryError
from sympy.geometry.curve import Curve
from sympy.geometry.parabola import Parabola
__all__ = [
'Point', 'Point2D', 'Point3D',
'Line', 'Ray', 'Segment', 'Line2D', 'Segment2D', 'Ray2D', 'Line3D',
'Segment3D', 'Ray3D',
'Plane',
'Ellipse', 'Circle',
'Polygon', 'RegularPolygon', 'Triangle', 'rad', 'deg',
'are_similar', 'centroid', 'convex_hull', 'idiff', 'intersection',
'closest_points', 'farthest_points',
'GeometryError',
'Curve',
'Parabola',
]
PK ]ZZZ���' �' sympy/geometry/curve.py"""Curves in 2-dimensional Euclidean space.
Contains
========
Curve
"""
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.core import diff
from sympy.core.containers import Tuple
from sympy.core.symbol import _symbol
from sympy.geometry.entity import GeometryEntity, GeometrySet
from sympy.geometry.point import Point
from sympy.integrals import integrate
from sympy.matrices import Matrix, rot_axis3
from sympy.utilities.iterables import is_sequence
from mpmath.libmp.libmpf import prec_to_dps
class Curve(GeometrySet):
"""A curve in space.
A curve is defined by parametric functions for the coordinates, a
parameter and the lower and upper bounds for the parameter value.
Parameters
==========
function : list of functions
limits : 3-tuple
Function parameter and lower and upper bounds.
Attributes
==========
functions
parameter
limits
Raises
======
ValueError
When `functions` are specified incorrectly.
When `limits` are specified incorrectly.
Examples
========
>>> from sympy import Curve, sin, cos, interpolate
>>> from sympy.abc import t, a
>>> C = Curve((sin(t), cos(t)), (t, 0, 2))
>>> C.functions
(sin(t), cos(t))
>>> C.limits
(t, 0, 2)
>>> C.parameter
t
>>> C = Curve((t, interpolate([1, 4, 9, 16], t)), (t, 0, 1)); C
Curve((t, t**2), (t, 0, 1))
>>> C.subs(t, 4)
Point2D(4, 16)
>>> C.arbitrary_point(a)
Point2D(a, a**2)
See Also
========
sympy.core.function.Function
sympy.polys.polyfuncs.interpolate
"""
def __new__(cls, function, limits):
if not is_sequence(function) or len(function) != 2:
raise ValueError("Function argument should be (x(t), y(t)) "
"but got %s" % str(function))
if not is_sequence(limits) or len(limits) != 3:
raise ValueError("Limit argument should be (t, tmin, tmax) "
"but got %s" % str(limits))
return GeometryEntity.__new__(cls, Tuple(*function), Tuple(*limits))
def __call__(self, f):
return self.subs(self.parameter, f)
def _eval_subs(self, old, new):
if old == self.parameter:
return Point(*[f.subs(old, new) for f in self.functions])
def _eval_evalf(self, prec=15, **options):
f, (t, a, b) = self.args
dps = prec_to_dps(prec)
f = tuple([i.evalf(n=dps, **options) for i in f])
a, b = [i.evalf(n=dps, **options) for i in (a, b)]
return self.func(f, (t, a, b))
def arbitrary_point(self, parameter='t'):
"""A parameterized point on the curve.
Parameters
==========
parameter : str or Symbol, optional
Default value is 't'.
The Curve's parameter is selected with None or self.parameter
otherwise the provided symbol is used.
Returns
=======
Point :
Returns a point in parametric form.
Raises
======
ValueError
When `parameter` already appears in the functions.
Examples
========
>>> from sympy import Curve, Symbol
>>> from sympy.abc import s
>>> C = Curve([2*s, s**2], (s, 0, 2))
>>> C.arbitrary_point()
Point2D(2*t, t**2)
>>> C.arbitrary_point(C.parameter)
Point2D(2*s, s**2)
>>> C.arbitrary_point(None)
Point2D(2*s, s**2)
>>> C.arbitrary_point(Symbol('a'))
Point2D(2*a, a**2)
See Also
========
sympy.geometry.point.Point
"""
if parameter is None:
return Point(*self.functions)
tnew = _symbol(parameter, self.parameter, real=True)
t = self.parameter
if (tnew.name != t.name and
tnew.name in (f.name for f in self.free_symbols)):
raise ValueError('Symbol %s already appears in object '
'and cannot be used as a parameter.' % tnew.name)
return Point(*[w.subs(t, tnew) for w in self.functions])
@property
def free_symbols(self):
"""Return a set of symbols other than the bound symbols used to
parametrically define the Curve.
Returns
=======
set :
Set of all non-parameterized symbols.
Examples
========
>>> from sympy.abc import t, a
>>> from sympy import Curve
>>> Curve((t, t**2), (t, 0, 2)).free_symbols
set()
>>> Curve((t, t**2), (t, a, 2)).free_symbols
{a}
"""
free = set()
for a in self.functions + self.limits[1:]:
free |= a.free_symbols
free = free.difference({self.parameter})
return free
@property
def ambient_dimension(self):
"""The dimension of the curve.
Returns
=======
int :
the dimension of curve.
Examples
========
>>> from sympy.abc import t
>>> from sympy import Curve
>>> C = Curve((t, t**2), (t, 0, 2))
>>> C.ambient_dimension
2
"""
return len(self.args[0])
@property
def functions(self):
"""The functions specifying the curve.
Returns
=======
functions :
list of parameterized coordinate functions.
Examples
========
>>> from sympy.abc import t
>>> from sympy import Curve
>>> C = Curve((t, t**2), (t, 0, 2))
>>> C.functions
(t, t**2)
See Also
========
parameter
"""
return self.args[0]
@property
def limits(self):
"""The limits for the curve.
Returns
=======
limits : tuple
Contains parameter and lower and upper limits.
Examples
========
>>> from sympy.abc import t
>>> from sympy import Curve
>>> C = Curve([t, t**3], (t, -2, 2))
>>> C.limits
(t, -2, 2)
See Also
========
plot_interval
"""
return self.args[1]
@property
def parameter(self):
"""The curve function variable.
Returns
=======
Symbol :
returns a bound symbol.
Examples
========
>>> from sympy.abc import t
>>> from sympy import Curve
>>> C = Curve([t, t**2], (t, 0, 2))
>>> C.parameter
t
See Also
========
functions
"""
return self.args[1][0]
@property
def length(self):
"""The curve length.
Examples
========
>>> from sympy import Curve
>>> from sympy.abc import t
>>> Curve((t, t), (t, 0, 1)).length
sqrt(2)
"""
integrand = sqrt(sum(diff(func, self.limits[0])**2 for func in self.functions))
return integrate(integrand, self.limits)
def plot_interval(self, parameter='t'):
"""The plot interval for the default geometric plot of the curve.
Parameters
==========
parameter : str or Symbol, optional
Default value is 't';
otherwise the provided symbol is used.
Returns
=======
List :
the plot interval as below:
[parameter, lower_bound, upper_bound]
Examples
========
>>> from sympy import Curve, sin
>>> from sympy.abc import x, s
>>> Curve((x, sin(x)), (x, 1, 2)).plot_interval()
[t, 1, 2]
>>> Curve((x, sin(x)), (x, 1, 2)).plot_interval(s)
[s, 1, 2]
See Also
========
limits : Returns limits of the parameter interval
"""
t = _symbol(parameter, self.parameter, real=True)
return [t] + list(self.limits[1:])
def rotate(self, angle=0, pt=None):
"""This function is used to rotate a curve along given point ``pt`` at given angle(in radian).
Parameters
==========
angle :
the angle at which the curve will be rotated(in radian) in counterclockwise direction.
default value of angle is 0.
pt : Point
the point along which the curve will be rotated.
If no point given, the curve will be rotated around origin.
Returns
=======
Curve :
returns a curve rotated at given angle along given point.
Examples
========
>>> from sympy import Curve, pi
>>> from sympy.abc import x
>>> Curve((x, x), (x, 0, 1)).rotate(pi/2)
Curve((-x, x), (x, 0, 1))
"""
if pt:
pt = -Point(pt, dim=2)
else:
pt = Point(0,0)
rv = self.translate(*pt.args)
f = list(rv.functions)
f.append(0)
f = Matrix(1, 3, f)
f *= rot_axis3(angle)
rv = self.func(f[0, :2].tolist()[0], self.limits)
pt = -pt
return rv.translate(*pt.args)
def scale(self, x=1, y=1, pt=None):
"""Override GeometryEntity.scale since Curve is not made up of Points.
Returns
=======
Curve :
returns scaled curve.
Examples
========
>>> from sympy import Curve
>>> from sympy.abc import x
>>> Curve((x, x), (x, 0, 1)).scale(2)
Curve((2*x, x), (x, 0, 1))
"""
if pt:
pt = Point(pt, dim=2)
return self.translate(*(-pt).args).scale(x, y).translate(*pt.args)
fx, fy = self.functions
return self.func((fx*x, fy*y), self.limits)
def translate(self, x=0, y=0):
"""Translate the Curve by (x, y).
Returns
=======
Curve :
returns a translated curve.
Examples
========
>>> from sympy import Curve
>>> from sympy.abc import x
>>> Curve((x, x), (x, 0, 1)).translate(1, 2)
Curve((x + 1, x + 2), (x, 0, 1))
"""
fx, fy = self.functions
return self.func((fx + x, fy + y), self.limits)
PK ]ZZZ��EyW� W� sympy/geometry/ellipse.py"""Elliptical geometrical entities.
Contains
* Ellipse
* Circle
"""
from sympy.core.expr import Expr
from sympy.core.relational import Eq
from sympy.core import S, pi, sympify
from sympy.core.evalf import N
from sympy.core.parameters import global_parameters
from sympy.core.logic import fuzzy_bool
from sympy.core.numbers import Rational, oo
from sympy.core.sorting import ordered
from sympy.core.symbol import Dummy, uniquely_named_symbol, _symbol
from sympy.simplify import simplify, trigsimp
from sympy.functions.elementary.miscellaneous import sqrt, Max
from sympy.functions.elementary.trigonometric import cos, sin
from sympy.functions.special.elliptic_integrals import elliptic_e
from .entity import GeometryEntity, GeometrySet
from .exceptions import GeometryError
from .line import Line, Segment, Ray2D, Segment2D, Line2D, LinearEntity3D
from .point import Point, Point2D, Point3D
from .util import idiff, find
from sympy.polys import DomainError, Poly, PolynomialError
from sympy.polys.polyutils import _not_a_coeff, _nsort
from sympy.solvers import solve
from sympy.solvers.solveset import linear_coeffs
from sympy.utilities.misc import filldedent, func_name
from mpmath.libmp.libmpf import prec_to_dps
import random
x, y = [Dummy('ellipse_dummy', real=True) for i in range(2)]
class Ellipse(GeometrySet):
"""An elliptical GeometryEntity.
Parameters
==========
center : Point, optional
Default value is Point(0, 0)
hradius : number or SymPy expression, optional
vradius : number or SymPy expression, optional
eccentricity : number or SymPy expression, optional
Two of `hradius`, `vradius` and `eccentricity` must be supplied to
create an Ellipse. The third is derived from the two supplied.
Attributes
==========
center
hradius
vradius
area
circumference
eccentricity
periapsis
apoapsis
focus_distance
foci
Raises
======
GeometryError
When `hradius`, `vradius` and `eccentricity` are incorrectly supplied
as parameters.
TypeError
When `center` is not a Point.
See Also
========
Circle
Notes
-----
Constructed from a center and two radii, the first being the horizontal
radius (along the x-axis) and the second being the vertical radius (along
the y-axis).
When symbolic value for hradius and vradius are used, any calculation that
refers to the foci or the major or minor axis will assume that the ellipse
has its major radius on the x-axis. If this is not true then a manual
rotation is necessary.
Examples
========
>>> from sympy import Ellipse, Point, Rational
>>> e1 = Ellipse(Point(0, 0), 5, 1)
>>> e1.hradius, e1.vradius
(5, 1)
>>> e2 = Ellipse(Point(3, 1), hradius=3, eccentricity=Rational(4, 5))
>>> e2
Ellipse(Point2D(3, 1), 3, 9/5)
"""
def __contains__(self, o):
if isinstance(o, Point):
res = self.equation(x, y).subs({x: o.x, y: o.y})
return trigsimp(simplify(res)) is S.Zero
elif isinstance(o, Ellipse):
return self == o
return False
def __eq__(self, o):
"""Is the other GeometryEntity the same as this ellipse?"""
return isinstance(o, Ellipse) and (self.center == o.center and
self.hradius == o.hradius and
self.vradius == o.vradius)
def __hash__(self):
return super().__hash__()
def __new__(
cls, center=None, hradius=None, vradius=None, eccentricity=None, **kwargs):
hradius = sympify(hradius)
vradius = sympify(vradius)
if center is None:
center = Point(0, 0)
else:
if len(center) != 2:
raise ValueError('The center of "{}" must be a two dimensional point'.format(cls))
center = Point(center, dim=2)
if len(list(filter(lambda x: x is not None, (hradius, vradius, eccentricity)))) != 2:
raise ValueError(filldedent('''
Exactly two arguments of "hradius", "vradius", and
"eccentricity" must not be None.'''))
if eccentricity is not None:
eccentricity = sympify(eccentricity)
if eccentricity.is_negative:
raise GeometryError("Eccentricity of ellipse/circle should lie between [0, 1)")
elif hradius is None:
hradius = vradius / sqrt(1 - eccentricity**2)
elif vradius is None:
vradius = hradius * sqrt(1 - eccentricity**2)
if hradius == vradius:
return Circle(center, hradius, **kwargs)
if S.Zero in (hradius, vradius):
return Segment(Point(center[0] - hradius, center[1] - vradius), Point(center[0] + hradius, center[1] + vradius))
if hradius.is_real is False or vradius.is_real is False:
raise GeometryError("Invalid value encountered when computing hradius / vradius.")
return GeometryEntity.__new__(cls, center, hradius, vradius, **kwargs)
def _svg(self, scale_factor=1., fill_color="#66cc99"):
"""Returns SVG ellipse element for the Ellipse.
Parameters
==========
scale_factor : float
Multiplication factor for the SVG stroke-width. Default is 1.
fill_color : str, optional
Hex string for fill color. Default is "#66cc99".
"""
c = N(self.center)
h, v = N(self.hradius), N(self.vradius)
return (
'<ellipse fill="{1}" stroke="#555555" '
'stroke-width="{0}" opacity="0.6" cx="{2}" cy="{3}" rx="{4}" ry="{5}"/>'
).format(2. * scale_factor, fill_color, c.x, c.y, h, v)
@property
def ambient_dimension(self):
return 2
@property
def apoapsis(self):
"""The apoapsis of the ellipse.
The greatest distance between the focus and the contour.
Returns
=======
apoapsis : number
See Also
========
periapsis : Returns shortest distance between foci and contour
Examples
========
>>> from sympy import Point, Ellipse
>>> p1 = Point(0, 0)
>>> e1 = Ellipse(p1, 3, 1)
>>> e1.apoapsis
2*sqrt(2) + 3
"""
return self.major * (1 + self.eccentricity)
def arbitrary_point(self, parameter='t'):
"""A parameterized point on the ellipse.
Parameters
==========
parameter : str, optional
Default value is 't'.
Returns
=======
arbitrary_point : Point
Raises
======
ValueError
When `parameter` already appears in the functions.
See Also
========
sympy.geometry.point.Point
Examples
========
>>> from sympy import Point, Ellipse
>>> e1 = Ellipse(Point(0, 0), 3, 2)
>>> e1.arbitrary_point()
Point2D(3*cos(t), 2*sin(t))
"""
t = _symbol(parameter, real=True)
if t.name in (f.name for f in self.free_symbols):
raise ValueError(filldedent('Symbol %s already appears in object '
'and cannot be used as a parameter.' % t.name))
return Point(self.center.x + self.hradius*cos(t),
self.center.y + self.vradius*sin(t))
@property
def area(self):
"""The area of the ellipse.
Returns
=======
area : number
Examples
========
>>> from sympy import Point, Ellipse
>>> p1 = Point(0, 0)
>>> e1 = Ellipse(p1, 3, 1)
>>> e1.area
3*pi
"""
return simplify(S.Pi * self.hradius * self.vradius)
@property
def bounds(self):
"""Return a tuple (xmin, ymin, xmax, ymax) representing the bounding
rectangle for the geometric figure.
"""
h, v = self.hradius, self.vradius
return (self.center.x - h, self.center.y - v, self.center.x + h, self.center.y + v)
@property
def center(self):
"""The center of the ellipse.
Returns
=======
center : number
See Also
========
sympy.geometry.point.Point
Examples
========
>>> from sympy import Point, Ellipse
>>> p1 = Point(0, 0)
>>> e1 = Ellipse(p1, 3, 1)
>>> e1.center
Point2D(0, 0)
"""
return self.args[0]
@property
def circumference(self):
"""The circumference of the ellipse.
Examples
========
>>> from sympy import Point, Ellipse
>>> p1 = Point(0, 0)
>>> e1 = Ellipse(p1, 3, 1)
>>> e1.circumference
12*elliptic_e(8/9)
"""
if self.eccentricity == 1:
# degenerate
return 4*self.major
elif self.eccentricity == 0:
# circle
return 2*pi*self.hradius
else:
return 4*self.major*elliptic_e(self.eccentricity**2)
@property
def eccentricity(self):
"""The eccentricity of the ellipse.
Returns
=======
eccentricity : number
Examples
========
>>> from sympy import Point, Ellipse, sqrt
>>> p1 = Point(0, 0)
>>> e1 = Ellipse(p1, 3, sqrt(2))
>>> e1.eccentricity
sqrt(7)/3
"""
return self.focus_distance / self.major
def encloses_point(self, p):
"""
Return True if p is enclosed by (is inside of) self.
Notes
-----
Being on the border of self is considered False.
Parameters
==========
p : Point
Returns
=======
encloses_point : True, False or None
See Also
========
sympy.geometry.point.Point
Examples
========
>>> from sympy import Ellipse, S
>>> from sympy.abc import t
>>> e = Ellipse((0, 0), 3, 2)
>>> e.encloses_point((0, 0))
True
>>> e.encloses_point(e.arbitrary_point(t).subs(t, S.Half))
False
>>> e.encloses_point((4, 0))
False
"""
p = Point(p, dim=2)
if p in self:
return False
if len(self.foci) == 2:
# if the combined distance from the foci to p (h1 + h2) is less
# than the combined distance from the foci to the minor axis
# (which is the same as the major axis length) then p is inside
# the ellipse
h1, h2 = [f.distance(p) for f in self.foci]
test = 2*self.major - (h1 + h2)
else:
test = self.radius - self.center.distance(p)
return fuzzy_bool(test.is_positive)
def equation(self, x='x', y='y', _slope=None):
"""
Returns the equation of an ellipse aligned with the x and y axes;
when slope is given, the equation returned corresponds to an ellipse
with a major axis having that slope.
Parameters
==========
x : str, optional
Label for the x-axis. Default value is 'x'.
y : str, optional
Label for the y-axis. Default value is 'y'.
_slope : Expr, optional
The slope of the major axis. Ignored when 'None'.
Returns
=======
equation : SymPy expression
See Also
========
arbitrary_point : Returns parameterized point on ellipse
Examples
========
>>> from sympy import Point, Ellipse, pi
>>> from sympy.abc import x, y
>>> e1 = Ellipse(Point(1, 0), 3, 2)
>>> eq1 = e1.equation(x, y); eq1
y**2/4 + (x/3 - 1/3)**2 - 1
>>> eq2 = e1.equation(x, y, _slope=1); eq2
(-x + y + 1)**2/8 + (x + y - 1)**2/18 - 1
A point on e1 satisfies eq1. Let's use one on the x-axis:
>>> p1 = e1.center + Point(e1.major, 0)
>>> assert eq1.subs(x, p1.x).subs(y, p1.y) == 0
When rotated the same as the rotated ellipse, about the center
point of the ellipse, it will satisfy the rotated ellipse's
equation, too:
>>> r1 = p1.rotate(pi/4, e1.center)
>>> assert eq2.subs(x, r1.x).subs(y, r1.y) == 0
References
==========
.. [1] https://math.stackexchange.com/questions/108270/what-is-the-equation-of-an-ellipse-that-is-not-aligned-with-the-axis
.. [2] https://en.wikipedia.org/wiki/Ellipse#Shifted_ellipse
"""
x = _symbol(x, real=True)
y = _symbol(y, real=True)
dx = x - self.center.x
dy = y - self.center.y
if _slope is not None:
L = (dy - _slope*dx)**2
l = (_slope*dy + dx)**2
h = 1 + _slope**2
b = h*self.major**2
a = h*self.minor**2
return l/b + L/a - 1
else:
t1 = (dx/self.hradius)**2
t2 = (dy/self.vradius)**2
return t1 + t2 - 1
def evolute(self, x='x', y='y'):
"""The equation of evolute of the ellipse.
Parameters
==========
x : str, optional
Label for the x-axis. Default value is 'x'.
y : str, optional
Label for the y-axis. Default value is 'y'.
Returns
=======
equation : SymPy expression
Examples
========
>>> from sympy import Point, Ellipse
>>> e1 = Ellipse(Point(1, 0), 3, 2)
>>> e1.evolute()
2**(2/3)*y**(2/3) + (3*x - 3)**(2/3) - 5**(2/3)
"""
if len(self.args) != 3:
raise NotImplementedError('Evolute of arbitrary Ellipse is not supported.')
x = _symbol(x, real=True)
y = _symbol(y, real=True)
t1 = (self.hradius*(x - self.center.x))**Rational(2, 3)
t2 = (self.vradius*(y - self.center.y))**Rational(2, 3)
return t1 + t2 - (self.hradius**2 - self.vradius**2)**Rational(2, 3)
@property
def foci(self):
"""The foci of the ellipse.
Notes
-----
The foci can only be calculated if the major/minor axes are known.
Raises
======
ValueError
When the major and minor axis cannot be determined.
See Also
========
sympy.geometry.point.Point
focus_distance : Returns the distance between focus and center
Examples
========
>>> from sympy import Point, Ellipse
>>> p1 = Point(0, 0)
>>> e1 = Ellipse(p1, 3, 1)
>>> e1.foci
(Point2D(-2*sqrt(2), 0), Point2D(2*sqrt(2), 0))
"""
c = self.center
hr, vr = self.hradius, self.vradius
if hr == vr:
return (c, c)
# calculate focus distance manually, since focus_distance calls this
# routine
fd = sqrt(self.major**2 - self.minor**2)
if hr == self.minor:
# foci on the y-axis
return (c + Point(0, -fd), c + Point(0, fd))
elif hr == self.major:
# foci on the x-axis
return (c + Point(-fd, 0), c + Point(fd, 0))
@property
def focus_distance(self):
"""The focal distance of the ellipse.
The distance between the center and one focus.
Returns
=======
focus_distance : number
See Also
========
foci
Examples
========
>>> from sympy import Point, Ellipse
>>> p1 = Point(0, 0)
>>> e1 = Ellipse(p1, 3, 1)
>>> e1.focus_distance
2*sqrt(2)
"""
return Point.distance(self.center, self.foci[0])
@property
def hradius(self):
"""The horizontal radius of the ellipse.
Returns
=======
hradius : number
See Also
========
vradius, major, minor
Examples
========
>>> from sympy import Point, Ellipse
>>> p1 = Point(0, 0)
>>> e1 = Ellipse(p1, 3, 1)
>>> e1.hradius
3
"""
return self.args[1]
def intersection(self, o):
"""The intersection of this ellipse and another geometrical entity
`o`.
Parameters
==========
o : GeometryEntity
Returns
=======
intersection : list of GeometryEntity objects
Notes
-----
Currently supports intersections with Point, Line, Segment, Ray,
Circle and Ellipse types.
See Also
========
sympy.geometry.entity.GeometryEntity
Examples
========
>>> from sympy import Ellipse, Point, Line
>>> e = Ellipse(Point(0, 0), 5, 7)
>>> e.intersection(Point(0, 0))
[]
>>> e.intersection(Point(5, 0))
[Point2D(5, 0)]
>>> e.intersection(Line(Point(0,0), Point(0, 1)))
[Point2D(0, -7), Point2D(0, 7)]
>>> e.intersection(Line(Point(5,0), Point(5, 1)))
[Point2D(5, 0)]
>>> e.intersection(Line(Point(6,0), Point(6, 1)))
[]
>>> e = Ellipse(Point(-1, 0), 4, 3)
>>> e.intersection(Ellipse(Point(1, 0), 4, 3))
[Point2D(0, -3*sqrt(15)/4), Point2D(0, 3*sqrt(15)/4)]
>>> e.intersection(Ellipse(Point(5, 0), 4, 3))
[Point2D(2, -3*sqrt(7)/4), Point2D(2, 3*sqrt(7)/4)]
>>> e.intersection(Ellipse(Point(100500, 0), 4, 3))
[]
>>> e.intersection(Ellipse(Point(0, 0), 3, 4))
[Point2D(3, 0), Point2D(-363/175, -48*sqrt(111)/175), Point2D(-363/175, 48*sqrt(111)/175)]
>>> e.intersection(Ellipse(Point(-1, 0), 3, 4))
[Point2D(-17/5, -12/5), Point2D(-17/5, 12/5), Point2D(7/5, -12/5), Point2D(7/5, 12/5)]
"""
# TODO: Replace solve with nonlinsolve, when nonlinsolve will be able to solve in real domain
if isinstance(o, Point):
if o in self:
return [o]
else:
return []
elif isinstance(o, (Segment2D, Ray2D)):
ellipse_equation = self.equation(x, y)
result = solve([ellipse_equation, Line(
o.points[0], o.points[1]).equation(x, y)], [x, y],
set=True)[1]
return list(ordered([Point(i) for i in result if i in o]))
elif isinstance(o, Polygon):
return o.intersection(self)
elif isinstance(o, (Ellipse, Line2D)):
if o == self:
return self
else:
ellipse_equation = self.equation(x, y)
return list(ordered([Point(i) for i in solve(
[ellipse_equation, o.equation(x, y)], [x, y],
set=True)[1]]))
elif isinstance(o, LinearEntity3D):
raise TypeError('Entity must be two dimensional, not three dimensional')
else:
raise TypeError('Intersection not handled for %s' % func_name(o))
def is_tangent(self, o):
"""Is `o` tangent to the ellipse?
Parameters
==========
o : GeometryEntity
An Ellipse, LinearEntity or Polygon
Raises
======
NotImplementedError
When the wrong type of argument is supplied.
Returns
=======
is_tangent: boolean
True if o is tangent to the ellipse, False otherwise.
See Also
========
tangent_lines
Examples
========
>>> from sympy import Point, Ellipse, Line
>>> p0, p1, p2 = Point(0, 0), Point(3, 0), Point(3, 3)
>>> e1 = Ellipse(p0, 3, 2)
>>> l1 = Line(p1, p2)
>>> e1.is_tangent(l1)
True
"""
if isinstance(o, Point2D):
return False
elif isinstance(o, Ellipse):
intersect = self.intersection(o)
if isinstance(intersect, Ellipse):
return True
elif intersect:
return all((self.tangent_lines(i)[0]).equals(o.tangent_lines(i)[0]) for i in intersect)
else:
return False
elif isinstance(o, Line2D):
hit = self.intersection(o)
if not hit:
return False
if len(hit) == 1:
return True
# might return None if it can't decide
return hit[0].equals(hit[1])
elif isinstance(o, (Segment2D, Ray2D)):
intersect = self.intersection(o)
if len(intersect) == 1:
return o in self.tangent_lines(intersect[0])[0]
else:
return False
elif isinstance(o, Polygon):
return all(self.is_tangent(s) for s in o.sides)
elif isinstance(o, (LinearEntity3D, Point3D)):
raise TypeError('Entity must be two dimensional, not three dimensional')
else:
raise TypeError('Is_tangent not handled for %s' % func_name(o))
@property
def major(self):
"""Longer axis of the ellipse (if it can be determined) else hradius.
Returns
=======
major : number or expression
See Also
========
hradius, vradius, minor
Examples
========
>>> from sympy import Point, Ellipse, Symbol
>>> p1 = Point(0, 0)
>>> e1 = Ellipse(p1, 3, 1)
>>> e1.major
3
>>> a = Symbol('a')
>>> b = Symbol('b')
>>> Ellipse(p1, a, b).major
a
>>> Ellipse(p1, b, a).major
b
>>> m = Symbol('m')
>>> M = m + 1
>>> Ellipse(p1, m, M).major
m + 1
"""
ab = self.args[1:3]
if len(ab) == 1:
return ab[0]
a, b = ab
o = b - a < 0
if o == True:
return a
elif o == False:
return b
return self.hradius
@property
def minor(self):
"""Shorter axis of the ellipse (if it can be determined) else vradius.
Returns
=======
minor : number or expression
See Also
========
hradius, vradius, major
Examples
========
>>> from sympy import Point, Ellipse, Symbol
>>> p1 = Point(0, 0)
>>> e1 = Ellipse(p1, 3, 1)
>>> e1.minor
1
>>> a = Symbol('a')
>>> b = Symbol('b')
>>> Ellipse(p1, a, b).minor
b
>>> Ellipse(p1, b, a).minor
a
>>> m = Symbol('m')
>>> M = m + 1
>>> Ellipse(p1, m, M).minor
m
"""
ab = self.args[1:3]
if len(ab) == 1:
return ab[0]
a, b = ab
o = a - b < 0
if o == True:
return a
elif o == False:
return b
return self.vradius
def normal_lines(self, p, prec=None):
"""Normal lines between `p` and the ellipse.
Parameters
==========
p : Point
Returns
=======
normal_lines : list with 1, 2 or 4 Lines
Examples
========
>>> from sympy import Point, Ellipse
>>> e = Ellipse((0, 0), 2, 3)
>>> c = e.center
>>> e.normal_lines(c + Point(1, 0))
[Line2D(Point2D(0, 0), Point2D(1, 0))]
>>> e.normal_lines(c)
[Line2D(Point2D(0, 0), Point2D(0, 1)), Line2D(Point2D(0, 0), Point2D(1, 0))]
Off-axis points require the solution of a quartic equation. This
often leads to very large expressions that may be of little practical
use. An approximate solution of `prec` digits can be obtained by
passing in the desired value:
>>> e.normal_lines((3, 3), prec=2)
[Line2D(Point2D(-0.81, -2.7), Point2D(0.19, -1.2)),
Line2D(Point2D(1.5, -2.0), Point2D(2.5, -2.7))]
Whereas the above solution has an operation count of 12, the exact
solution has an operation count of 2020.
"""
p = Point(p, dim=2)
# XXX change True to something like self.angle == 0 if the arbitrarily
# rotated ellipse is introduced.
# https://github.com/sympy/sympy/issues/2815)
if True:
rv = []
if p.x == self.center.x:
rv.append(Line(self.center, slope=oo))
if p.y == self.center.y:
rv.append(Line(self.center, slope=0))
if rv:
# at these special orientations of p either 1 or 2 normals
# exist and we are done
return rv
# find the 4 normal points and construct lines through them with
# the corresponding slope
eq = self.equation(x, y)
dydx = idiff(eq, y, x)
norm = -1/dydx
slope = Line(p, (x, y)).slope
seq = slope - norm
# TODO: Replace solve with solveset, when this line is tested
yis = solve(seq, y)[0]
xeq = eq.subs(y, yis).as_numer_denom()[0].expand()
if len(xeq.free_symbols) == 1:
try:
# this is so much faster, it's worth a try
xsol = Poly(xeq, x).real_roots()
except (DomainError, PolynomialError, NotImplementedError):
# TODO: Replace solve with solveset, when these lines are tested
xsol = _nsort(solve(xeq, x), separated=True)[0]
points = [Point(i, solve(eq.subs(x, i), y)[0]) for i in xsol]
else:
raise NotImplementedError(
'intersections for the general ellipse are not supported')
slopes = [norm.subs(zip((x, y), pt.args)) for pt in points]
if prec is not None:
points = [pt.n(prec) for pt in points]
slopes = [i if _not_a_coeff(i) else i.n(prec) for i in slopes]
return [Line(pt, slope=s) for pt, s in zip(points, slopes)]
@property
def periapsis(self):
"""The periapsis of the ellipse.
The shortest distance between the focus and the contour.
Returns
=======
periapsis : number
See Also
========
apoapsis : Returns greatest distance between focus and contour
Examples
========
>>> from sympy import Point, Ellipse
>>> p1 = Point(0, 0)
>>> e1 = Ellipse(p1, 3, 1)
>>> e1.periapsis
3 - 2*sqrt(2)
"""
return self.major * (1 - self.eccentricity)
@property
def semilatus_rectum(self):
"""
Calculates the semi-latus rectum of the Ellipse.
Semi-latus rectum is defined as one half of the chord through a
focus parallel to the conic section directrix of a conic section.
Returns
=======
semilatus_rectum : number
See Also
========
apoapsis : Returns greatest distance between focus and contour
periapsis : The shortest distance between the focus and the contour
Examples
========
>>> from sympy import Point, Ellipse
>>> p1 = Point(0, 0)
>>> e1 = Ellipse(p1, 3, 1)
>>> e1.semilatus_rectum
1/3
References
==========
.. [1] https://mathworld.wolfram.com/SemilatusRectum.html
.. [2] https://en.wikipedia.org/wiki/Ellipse#Semi-latus_rectum
"""
return self.major * (1 - self.eccentricity ** 2)
def auxiliary_circle(self):
"""Returns a Circle whose diameter is the major axis of the ellipse.
Examples
========
>>> from sympy import Ellipse, Point, symbols
>>> c = Point(1, 2)
>>> Ellipse(c, 8, 7).auxiliary_circle()
Circle(Point2D(1, 2), 8)
>>> a, b = symbols('a b')
>>> Ellipse(c, a, b).auxiliary_circle()
Circle(Point2D(1, 2), Max(a, b))
"""
return Circle(self.center, Max(self.hradius, self.vradius))
def director_circle(self):
"""
Returns a Circle consisting of all points where two perpendicular
tangent lines to the ellipse cross each other.
Returns
=======
Circle
A director circle returned as a geometric object.
Examples
========
>>> from sympy import Ellipse, Point, symbols
>>> c = Point(3,8)
>>> Ellipse(c, 7, 9).director_circle()
Circle(Point2D(3, 8), sqrt(130))
>>> a, b = symbols('a b')
>>> Ellipse(c, a, b).director_circle()
Circle(Point2D(3, 8), sqrt(a**2 + b**2))
References
==========
.. [1] https://en.wikipedia.org/wiki/Director_circle
"""
return Circle(self.center, sqrt(self.hradius**2 + self.vradius**2))
def plot_interval(self, parameter='t'):
"""The plot interval for the default geometric plot of the Ellipse.
Parameters
==========
parameter : str, optional
Default value is 't'.
Returns
=======
plot_interval : list
[parameter, lower_bound, upper_bound]
Examples
========
>>> from sympy import Point, Ellipse
>>> e1 = Ellipse(Point(0, 0), 3, 2)
>>> e1.plot_interval()
[t, -pi, pi]
"""
t = _symbol(parameter, real=True)
return [t, -S.Pi, S.Pi]
def random_point(self, seed=None):
"""A random point on the ellipse.
Returns
=======
point : Point
Examples
========
>>> from sympy import Point, Ellipse
>>> e1 = Ellipse(Point(0, 0), 3, 2)
>>> e1.random_point() # gives some random point
Point2D(...)
>>> p1 = e1.random_point(seed=0); p1.n(2)
Point2D(2.1, 1.4)
Notes
=====
When creating a random point, one may simply replace the
parameter with a random number. When doing so, however, the
random number should be made a Rational or else the point
may not test as being in the ellipse:
>>> from sympy.abc import t
>>> from sympy import Rational
>>> arb = e1.arbitrary_point(t); arb
Point2D(3*cos(t), 2*sin(t))
>>> arb.subs(t, .1) in e1
False
>>> arb.subs(t, Rational(.1)) in e1
True
>>> arb.subs(t, Rational('.1')) in e1
True
See Also
========
sympy.geometry.point.Point
arbitrary_point : Returns parameterized point on ellipse
"""
t = _symbol('t', real=True)
x, y = self.arbitrary_point(t).args
# get a random value in [-1, 1) corresponding to cos(t)
# and confirm that it will test as being in the ellipse
if seed is not None:
rng = random.Random(seed)
else:
rng = random
# simplify this now or else the Float will turn s into a Float
r = Rational(rng.random())
c = 2*r - 1
s = sqrt(1 - c**2)
return Point(x.subs(cos(t), c), y.subs(sin(t), s))
def reflect(self, line):
"""Override GeometryEntity.reflect since the radius
is not a GeometryEntity.
Examples
========
>>> from sympy import Circle, Line
>>> Circle((0, 1), 1).reflect(Line((0, 0), (1, 1)))
Circle(Point2D(1, 0), -1)
>>> from sympy import Ellipse, Line, Point
>>> Ellipse(Point(3, 4), 1, 3).reflect(Line(Point(0, -4), Point(5, 0)))
Traceback (most recent call last):
...
NotImplementedError:
General Ellipse is not supported but the equation of the reflected
Ellipse is given by the zeros of: f(x, y) = (9*x/41 + 40*y/41 +
37/41)**2 + (40*x/123 - 3*y/41 - 364/123)**2 - 1
Notes
=====
Until the general ellipse (with no axis parallel to the x-axis) is
supported a NotImplemented error is raised and the equation whose
zeros define the rotated ellipse is given.
"""
if line.slope in (0, oo):
c = self.center
c = c.reflect(line)
return self.func(c, -self.hradius, self.vradius)
else:
x, y = [uniquely_named_symbol(
name, (self, line), modify=lambda s: '_' + s, real=True)
for name in 'xy']
expr = self.equation(x, y)
p = Point(x, y).reflect(line)
result = expr.subs(zip((x, y), p.args
), simultaneous=True)
raise NotImplementedError(filldedent(
'General Ellipse is not supported but the equation '
'of the reflected Ellipse is given by the zeros of: ' +
"f(%s, %s) = %s" % (str(x), str(y), str(result))))
def rotate(self, angle=0, pt=None):
"""Rotate ``angle`` radians counterclockwise about Point ``pt``.
Note: since the general ellipse is not supported, only rotations that
are integer multiples of pi/2 are allowed.
Examples
========
>>> from sympy import Ellipse, pi
>>> Ellipse((1, 0), 2, 1).rotate(pi/2)
Ellipse(Point2D(0, 1), 1, 2)
>>> Ellipse((1, 0), 2, 1).rotate(pi)
Ellipse(Point2D(-1, 0), 2, 1)
"""
if self.hradius == self.vradius:
return self.func(self.center.rotate(angle, pt), self.hradius)
if (angle/S.Pi).is_integer:
return super().rotate(angle, pt)
if (2*angle/S.Pi).is_integer:
return self.func(self.center.rotate(angle, pt), self.vradius, self.hradius)
# XXX see https://github.com/sympy/sympy/issues/2815 for general ellipes
raise NotImplementedError('Only rotations of pi/2 are currently supported for Ellipse.')
def scale(self, x=1, y=1, pt=None):
"""Override GeometryEntity.scale since it is the major and minor
axes which must be scaled and they are not GeometryEntities.
Examples
========
>>> from sympy import Ellipse
>>> Ellipse((0, 0), 2, 1).scale(2, 4)
Circle(Point2D(0, 0), 4)
>>> Ellipse((0, 0), 2, 1).scale(2)
Ellipse(Point2D(0, 0), 4, 1)
"""
c = self.center
if pt:
pt = Point(pt, dim=2)
return self.translate(*(-pt).args).scale(x, y).translate(*pt.args)
h = self.hradius
v = self.vradius
return self.func(c.scale(x, y), hradius=h*x, vradius=v*y)
def tangent_lines(self, p):
"""Tangent lines between `p` and the ellipse.
If `p` is on the ellipse, returns the tangent line through point `p`.
Otherwise, returns the tangent line(s) from `p` to the ellipse, or
None if no tangent line is possible (e.g., `p` inside ellipse).
Parameters
==========
p : Point
Returns
=======
tangent_lines : list with 1 or 2 Lines
Raises
======
NotImplementedError
Can only find tangent lines for a point, `p`, on the ellipse.
See Also
========
sympy.geometry.point.Point, sympy.geometry.line.Line
Examples
========
>>> from sympy import Point, Ellipse
>>> e1 = Ellipse(Point(0, 0), 3, 2)
>>> e1.tangent_lines(Point(3, 0))
[Line2D(Point2D(3, 0), Point2D(3, -12))]
"""
p = Point(p, dim=2)
if self.encloses_point(p):
return []
if p in self:
delta = self.center - p
rise = (self.vradius**2)*delta.x
run = -(self.hradius**2)*delta.y
p2 = Point(simplify(p.x + run),
simplify(p.y + rise))
return [Line(p, p2)]
else:
if len(self.foci) == 2:
f1, f2 = self.foci
maj = self.hradius
test = (2*maj -
Point.distance(f1, p) -
Point.distance(f2, p))
else:
test = self.radius - Point.distance(self.center, p)
if test.is_number and test.is_positive:
return []
# else p is outside the ellipse or we can't tell. In case of the
# latter, the solutions returned will only be valid if
# the point is not inside the ellipse; if it is, nan will result.
eq = self.equation(x, y)
dydx = idiff(eq, y, x)
slope = Line(p, Point(x, y)).slope
# TODO: Replace solve with solveset, when this line is tested
tangent_points = solve([slope - dydx, eq], [x, y])
# handle horizontal and vertical tangent lines
if len(tangent_points) == 1:
if tangent_points[0][
0] == p.x or tangent_points[0][1] == p.y:
return [Line(p, p + Point(1, 0)), Line(p, p + Point(0, 1))]
else:
return [Line(p, p + Point(0, 1)), Line(p, tangent_points[0])]
# others
return [Line(p, tangent_points[0]), Line(p, tangent_points[1])]
@property
def vradius(self):
"""The vertical radius of the ellipse.
Returns
=======
vradius : number
See Also
========
hradius, major, minor
Examples
========
>>> from sympy import Point, Ellipse
>>> p1 = Point(0, 0)
>>> e1 = Ellipse(p1, 3, 1)
>>> e1.vradius
1
"""
return self.args[2]
def second_moment_of_area(self, point=None):
"""Returns the second moment and product moment area of an ellipse.
Parameters
==========
point : Point, two-tuple of sympifiable objects, or None(default=None)
point is the point about which second moment of area is to be found.
If "point=None" it will be calculated about the axis passing through the
centroid of the ellipse.
Returns
=======
I_xx, I_yy, I_xy : number or SymPy expression
I_xx, I_yy are second moment of area of an ellise.
I_xy is product moment of area of an ellipse.
Examples
========
>>> from sympy import Point, Ellipse
>>> p1 = Point(0, 0)
>>> e1 = Ellipse(p1, 3, 1)
>>> e1.second_moment_of_area()
(3*pi/4, 27*pi/4, 0)
References
==========
.. [1] https://en.wikipedia.org/wiki/List_of_second_moments_of_area
"""
I_xx = (S.Pi*(self.hradius)*(self.vradius**3))/4
I_yy = (S.Pi*(self.hradius**3)*(self.vradius))/4
I_xy = 0
if point is None:
return I_xx, I_yy, I_xy
# parallel axis theorem
I_xx = I_xx + self.area*((point[1] - self.center.y)**2)
I_yy = I_yy + self.area*((point[0] - self.center.x)**2)
I_xy = I_xy + self.area*(point[0] - self.center.x)*(point[1] - self.center.y)
return I_xx, I_yy, I_xy
def polar_second_moment_of_area(self):
"""Returns the polar second moment of area of an Ellipse
It is a constituent of the second moment of area, linked through
the perpendicular axis theorem. While the planar second moment of
area describes an object's resistance to deflection (bending) when
subjected to a force applied to a plane parallel to the central
axis, the polar second moment of area describes an object's
resistance to deflection when subjected to a moment applied in a
plane perpendicular to the object's central axis (i.e. parallel to
the cross-section)
Examples
========
>>> from sympy import symbols, Circle, Ellipse
>>> c = Circle((5, 5), 4)
>>> c.polar_second_moment_of_area()
128*pi
>>> a, b = symbols('a, b')
>>> e = Ellipse((0, 0), a, b)
>>> e.polar_second_moment_of_area()
pi*a**3*b/4 + pi*a*b**3/4
References
==========
.. [1] https://en.wikipedia.org/wiki/Polar_moment_of_inertia
"""
second_moment = self.second_moment_of_area()
return second_moment[0] + second_moment[1]
def section_modulus(self, point=None):
"""Returns a tuple with the section modulus of an ellipse
Section modulus is a geometric property of an ellipse defined as the
ratio of second moment of area to the distance of the extreme end of
the ellipse from the centroidal axis.
Parameters
==========
point : Point, two-tuple of sympifyable objects, or None(default=None)
point is the point at which section modulus is to be found.
If "point=None" section modulus will be calculated for the
point farthest from the centroidal axis of the ellipse.
Returns
=======
S_x, S_y: numbers or SymPy expressions
S_x is the section modulus with respect to the x-axis
S_y is the section modulus with respect to the y-axis
A negative sign indicates that the section modulus is
determined for a point below the centroidal axis.
Examples
========
>>> from sympy import Symbol, Ellipse, Circle, Point2D
>>> d = Symbol('d', positive=True)
>>> c = Circle((0, 0), d/2)
>>> c.section_modulus()
(pi*d**3/32, pi*d**3/32)
>>> e = Ellipse(Point2D(0, 0), 2, 4)
>>> e.section_modulus()
(8*pi, 4*pi)
>>> e.section_modulus((2, 2))
(16*pi, 4*pi)
References
==========
.. [1] https://en.wikipedia.org/wiki/Section_modulus
"""
x_c, y_c = self.center
if point is None:
# taking x and y as maximum distances from centroid
x_min, y_min, x_max, y_max = self.bounds
y = max(y_c - y_min, y_max - y_c)
x = max(x_c - x_min, x_max - x_c)
else:
# taking x and y as distances of the given point from the center
point = Point2D(point)
y = point.y - y_c
x = point.x - x_c
second_moment = self.second_moment_of_area()
S_x = second_moment[0]/y
S_y = second_moment[1]/x
return S_x, S_y
class Circle(Ellipse):
"""A circle in space.
Constructed simply from a center and a radius, from three
non-collinear points, or the equation of a circle.
Parameters
==========
center : Point
radius : number or SymPy expression
points : sequence of three Points
equation : equation of a circle
Attributes
==========
radius (synonymous with hradius, vradius, major and minor)
circumference
equation
Raises
======
GeometryError
When the given equation is not that of a circle.
When trying to construct circle from incorrect parameters.
See Also
========
Ellipse, sympy.geometry.point.Point
Examples
========
>>> from sympy import Point, Circle, Eq
>>> from sympy.abc import x, y, a, b
A circle constructed from a center and radius:
>>> c1 = Circle(Point(0, 0), 5)
>>> c1.hradius, c1.vradius, c1.radius
(5, 5, 5)
A circle constructed from three points:
>>> c2 = Circle(Point(0, 0), Point(1, 1), Point(1, 0))
>>> c2.hradius, c2.vradius, c2.radius, c2.center
(sqrt(2)/2, sqrt(2)/2, sqrt(2)/2, Point2D(1/2, 1/2))
A circle can be constructed from an equation in the form
`a*x**2 + by**2 + gx + hy + c = 0`, too:
>>> Circle(x**2 + y**2 - 25)
Circle(Point2D(0, 0), 5)
If the variables corresponding to x and y are named something
else, their name or symbol can be supplied:
>>> Circle(Eq(a**2 + b**2, 25), x='a', y=b)
Circle(Point2D(0, 0), 5)
"""
def __new__(cls, *args, **kwargs):
evaluate = kwargs.get('evaluate', global_parameters.evaluate)
if len(args) == 1 and isinstance(args[0], (Expr, Eq)):
x = kwargs.get('x', 'x')
y = kwargs.get('y', 'y')
equation = args[0].expand()
if isinstance(equation, Eq):
equation = equation.lhs - equation.rhs
x = find(x, equation)
y = find(y, equation)
try:
a, b, c, d, e = linear_coeffs(equation, x**2, y**2, x, y)
except ValueError:
raise GeometryError("The given equation is not that of a circle.")
if S.Zero in (a, b) or a != b:
raise GeometryError("The given equation is not that of a circle.")
center_x = -c/a/2
center_y = -d/b/2
r2 = (center_x**2) + (center_y**2) - e/a
return Circle((center_x, center_y), sqrt(r2), evaluate=evaluate)
else:
c, r = None, None
if len(args) == 3:
args = [Point(a, dim=2, evaluate=evaluate) for a in args]
t = Triangle(*args)
if not isinstance(t, Triangle):
return t
c = t.circumcenter
r = t.circumradius
elif len(args) == 2:
# Assume (center, radius) pair
c = Point(args[0], dim=2, evaluate=evaluate)
r = args[1]
# this will prohibit imaginary radius
try:
r = Point(r, 0, evaluate=evaluate).x
except ValueError:
raise GeometryError("Circle with imaginary radius is not permitted")
if not (c is None or r is None):
if r == 0:
return c
return GeometryEntity.__new__(cls, c, r, **kwargs)
raise GeometryError("Circle.__new__ received unknown arguments")
def _eval_evalf(self, prec=15, **options):
pt, r = self.args
dps = prec_to_dps(prec)
pt = pt.evalf(n=dps, **options)
r = r.evalf(n=dps, **options)
return self.func(pt, r, evaluate=False)
@property
def circumference(self):
"""The circumference of the circle.
Returns
=======
circumference : number or SymPy expression
Examples
========
>>> from sympy import Point, Circle
>>> c1 = Circle(Point(3, 4), 6)
>>> c1.circumference
12*pi
"""
return 2 * S.Pi * self.radius
def equation(self, x='x', y='y'):
"""The equation of the circle.
Parameters
==========
x : str or Symbol, optional
Default value is 'x'.
y : str or Symbol, optional
Default value is 'y'.
Returns
=======
equation : SymPy expression
Examples
========
>>> from sympy import Point, Circle
>>> c1 = Circle(Point(0, 0), 5)
>>> c1.equation()
x**2 + y**2 - 25
"""
x = _symbol(x, real=True)
y = _symbol(y, real=True)
t1 = (x - self.center.x)**2
t2 = (y - self.center.y)**2
return t1 + t2 - self.major**2
def intersection(self, o):
"""The intersection of this circle with another geometrical entity.
Parameters
==========
o : GeometryEntity
Returns
=======
intersection : list of GeometryEntities
Examples
========
>>> from sympy import Point, Circle, Line, Ray
>>> p1, p2, p3 = Point(0, 0), Point(5, 5), Point(6, 0)
>>> p4 = Point(5, 0)
>>> c1 = Circle(p1, 5)
>>> c1.intersection(p2)
[]
>>> c1.intersection(p4)
[Point2D(5, 0)]
>>> c1.intersection(Ray(p1, p2))
[Point2D(5*sqrt(2)/2, 5*sqrt(2)/2)]
>>> c1.intersection(Line(p2, p3))
[]
"""
return Ellipse.intersection(self, o)
@property
def radius(self):
"""The radius of the circle.
Returns
=======
radius : number or SymPy expression
See Also
========
Ellipse.major, Ellipse.minor, Ellipse.hradius, Ellipse.vradius
Examples
========
>>> from sympy import Point, Circle
>>> c1 = Circle(Point(3, 4), 6)
>>> c1.radius
6
"""
return self.args[1]
def reflect(self, line):
"""Override GeometryEntity.reflect since the radius
is not a GeometryEntity.
Examples
========
>>> from sympy import Circle, Line
>>> Circle((0, 1), 1).reflect(Line((0, 0), (1, 1)))
Circle(Point2D(1, 0), -1)
"""
c = self.center
c = c.reflect(line)
return self.func(c, -self.radius)
def scale(self, x=1, y=1, pt=None):
"""Override GeometryEntity.scale since the radius
is not a GeometryEntity.
Examples
========
>>> from sympy import Circle
>>> Circle((0, 0), 1).scale(2, 2)
Circle(Point2D(0, 0), 2)
>>> Circle((0, 0), 1).scale(2, 4)
Ellipse(Point2D(0, 0), 2, 4)
"""
c = self.center
if pt:
pt = Point(pt, dim=2)
return self.translate(*(-pt).args).scale(x, y).translate(*pt.args)
c = c.scale(x, y)
x, y = [abs(i) for i in (x, y)]
if x == y:
return self.func(c, x*self.radius)
h = v = self.radius
return Ellipse(c, hradius=h*x, vradius=v*y)
@property
def vradius(self):
"""
This Ellipse property is an alias for the Circle's radius.
Whereas hradius, major and minor can use Ellipse's conventions,
the vradius does not exist for a circle. It is always a positive
value in order that the Circle, like Polygons, will have an
area that can be positive or negative as determined by the sign
of the hradius.
Examples
========
>>> from sympy import Point, Circle
>>> c1 = Circle(Point(3, 4), 6)
>>> c1.vradius
6
"""
return abs(self.radius)
from .polygon import Polygon, Triangle
PK ]ZZZ�t���P �P sympy/geometry/entity.py"""The definition of the base geometrical entity with attributes common to
all derived geometrical entities.
Contains
========
GeometryEntity
GeometricSet
Notes
=====
A GeometryEntity is any object that has special geometric properties.
A GeometrySet is a superclass of any GeometryEntity that can also
be viewed as a sympy.sets.Set. In particular, points are the only
GeometryEntity not considered a Set.
Rn is a GeometrySet representing n-dimensional Euclidean space. R2 and
R3 are currently the only ambient spaces implemented.
"""
from __future__ import annotations
from sympy.core.basic import Basic
from sympy.core.containers import Tuple
from sympy.core.evalf import EvalfMixin, N
from sympy.core.numbers import oo
from sympy.core.symbol import Dummy
from sympy.core.sympify import sympify
from sympy.functions.elementary.trigonometric import cos, sin, atan
from sympy.matrices import eye
from sympy.multipledispatch import dispatch
from sympy.printing import sstr
from sympy.sets import Set, Union, FiniteSet
from sympy.sets.handlers.intersection import intersection_sets
from sympy.sets.handlers.union import union_sets
from sympy.solvers.solvers import solve
from sympy.utilities.misc import func_name
from sympy.utilities.iterables import is_sequence
# How entities are ordered; used by __cmp__ in GeometryEntity
ordering_of_classes = [
"Point2D",
"Point3D",
"Point",
"Segment2D",
"Ray2D",
"Line2D",
"Segment3D",
"Line3D",
"Ray3D",
"Segment",
"Ray",
"Line",
"Plane",
"Triangle",
"RegularPolygon",
"Polygon",
"Circle",
"Ellipse",
"Curve",
"Parabola"
]
x, y = [Dummy('entity_dummy') for i in range(2)]
T = Dummy('entity_dummy', real=True)
class GeometryEntity(Basic, EvalfMixin):
"""The base class for all geometrical entities.
This class does not represent any particular geometric entity, it only
provides the implementation of some methods common to all subclasses.
"""
__slots__: tuple[str, ...] = ()
def __cmp__(self, other):
"""Comparison of two GeometryEntities."""
n1 = self.__class__.__name__
n2 = other.__class__.__name__
c = (n1 > n2) - (n1 < n2)
if not c:
return 0
i1 = -1
for cls in self.__class__.__mro__:
try:
i1 = ordering_of_classes.index(cls.__name__)
break
except ValueError:
i1 = -1
if i1 == -1:
return c
i2 = -1
for cls in other.__class__.__mro__:
try:
i2 = ordering_of_classes.index(cls.__name__)
break
except ValueError:
i2 = -1
if i2 == -1:
return c
return (i1 > i2) - (i1 < i2)
def __contains__(self, other):
"""Subclasses should implement this method for anything more complex than equality."""
if type(self) is type(other):
return self == other
raise NotImplementedError()
def __getnewargs__(self):
"""Returns a tuple that will be passed to __new__ on unpickling."""
return tuple(self.args)
def __ne__(self, o):
"""Test inequality of two geometrical entities."""
return not self == o
def __new__(cls, *args, **kwargs):
# Points are sequences, but they should not
# be converted to Tuples, so use this detection function instead.
def is_seq_and_not_point(a):
# we cannot use isinstance(a, Point) since we cannot import Point
if hasattr(a, 'is_Point') and a.is_Point:
return False
return is_sequence(a)
args = [Tuple(*a) if is_seq_and_not_point(a) else sympify(a) for a in args]
return Basic.__new__(cls, *args)
def __radd__(self, a):
"""Implementation of reverse add method."""
return a.__add__(self)
def __rtruediv__(self, a):
"""Implementation of reverse division method."""
return a.__truediv__(self)
def __repr__(self):
"""String representation of a GeometryEntity that can be evaluated
by sympy."""
return type(self).__name__ + repr(self.args)
def __rmul__(self, a):
"""Implementation of reverse multiplication method."""
return a.__mul__(self)
def __rsub__(self, a):
"""Implementation of reverse subtraction method."""
return a.__sub__(self)
def __str__(self):
"""String representation of a GeometryEntity."""
return type(self).__name__ + sstr(self.args)
def _eval_subs(self, old, new):
from sympy.geometry.point import Point, Point3D
if is_sequence(old) or is_sequence(new):
if isinstance(self, Point3D):
old = Point3D(old)
new = Point3D(new)
else:
old = Point(old)
new = Point(new)
return self._subs(old, new)
def _repr_svg_(self):
"""SVG representation of a GeometryEntity suitable for IPython"""
try:
bounds = self.bounds
except (NotImplementedError, TypeError):
# if we have no SVG representation, return None so IPython
# will fall back to the next representation
return None
if not all(x.is_number and x.is_finite for x in bounds):
return None
svg_top = '''<svg xmlns="http://www.w3.org/2000/svg"
xmlns:xlink="http://www.w3.org/1999/xlink"
width="{1}" height="{2}" viewBox="{0}"
preserveAspectRatio="xMinYMin meet">
<defs>
<marker id="markerCircle" markerWidth="8" markerHeight="8"
refx="5" refy="5" markerUnits="strokeWidth">
<circle cx="5" cy="5" r="1.5" style="stroke: none; fill:#000000;"/>
</marker>
<marker id="markerArrow" markerWidth="13" markerHeight="13" refx="2" refy="4"
orient="auto" markerUnits="strokeWidth">
<path d="M2,2 L2,6 L6,4" style="fill: #000000;" />
</marker>
<marker id="markerReverseArrow" markerWidth="13" markerHeight="13" refx="6" refy="4"
orient="auto" markerUnits="strokeWidth">
<path d="M6,2 L6,6 L2,4" style="fill: #000000;" />
</marker>
</defs>'''
# Establish SVG canvas that will fit all the data + small space
xmin, ymin, xmax, ymax = map(N, bounds)
if xmin == xmax and ymin == ymax:
# This is a point; buffer using an arbitrary size
xmin, ymin, xmax, ymax = xmin - .5, ymin -.5, xmax + .5, ymax + .5
else:
# Expand bounds by a fraction of the data ranges
expand = 0.1 # or 10%; this keeps arrowheads in view (R plots use 4%)
widest_part = max([xmax - xmin, ymax - ymin])
expand_amount = widest_part * expand
xmin -= expand_amount
ymin -= expand_amount
xmax += expand_amount
ymax += expand_amount
dx = xmax - xmin
dy = ymax - ymin
width = min([max([100., dx]), 300])
height = min([max([100., dy]), 300])
scale_factor = 1. if max(width, height) == 0 else max(dx, dy) / max(width, height)
try:
svg = self._svg(scale_factor)
except (NotImplementedError, TypeError):
# if we have no SVG representation, return None so IPython
# will fall back to the next representation
return None
view_box = "{} {} {} {}".format(xmin, ymin, dx, dy)
transform = "matrix(1,0,0,-1,0,{})".format(ymax + ymin)
svg_top = svg_top.format(view_box, width, height)
return svg_top + (
'<g transform="{}">{}</g></svg>'
).format(transform, svg)
def _svg(self, scale_factor=1., fill_color="#66cc99"):
"""Returns SVG path element for the GeometryEntity.
Parameters
==========
scale_factor : float
Multiplication factor for the SVG stroke-width. Default is 1.
fill_color : str, optional
Hex string for fill color. Default is "#66cc99".
"""
raise NotImplementedError()
def _sympy_(self):
return self
@property
def ambient_dimension(self):
"""What is the dimension of the space that the object is contained in?"""
raise NotImplementedError()
@property
def bounds(self):
"""Return a tuple (xmin, ymin, xmax, ymax) representing the bounding
rectangle for the geometric figure.
"""
raise NotImplementedError()
def encloses(self, o):
"""
Return True if o is inside (not on or outside) the boundaries of self.
The object will be decomposed into Points and individual Entities need
only define an encloses_point method for their class.
See Also
========
sympy.geometry.ellipse.Ellipse.encloses_point
sympy.geometry.polygon.Polygon.encloses_point
Examples
========
>>> from sympy import RegularPolygon, Point, Polygon
>>> t = Polygon(*RegularPolygon(Point(0, 0), 1, 3).vertices)
>>> t2 = Polygon(*RegularPolygon(Point(0, 0), 2, 3).vertices)
>>> t2.encloses(t)
True
>>> t.encloses(t2)
False
"""
from sympy.geometry.point import Point
from sympy.geometry.line import Segment, Ray, Line
from sympy.geometry.ellipse import Ellipse
from sympy.geometry.polygon import Polygon, RegularPolygon
if isinstance(o, Point):
return self.encloses_point(o)
elif isinstance(o, Segment):
return all(self.encloses_point(x) for x in o.points)
elif isinstance(o, (Ray, Line)):
return False
elif isinstance(o, Ellipse):
return self.encloses_point(o.center) and \
self.encloses_point(
Point(o.center.x + o.hradius, o.center.y)) and \
not self.intersection(o)
elif isinstance(o, Polygon):
if isinstance(o, RegularPolygon):
if not self.encloses_point(o.center):
return False
return all(self.encloses_point(v) for v in o.vertices)
raise NotImplementedError()
def equals(self, o):
return self == o
def intersection(self, o):
"""
Returns a list of all of the intersections of self with o.
Notes
=====
An entity is not required to implement this method.
If two different types of entities can intersect, the item with
higher index in ordering_of_classes should implement
intersections with anything having a lower index.
See Also
========
sympy.geometry.util.intersection
"""
raise NotImplementedError()
def is_similar(self, other):
"""Is this geometrical entity similar to another geometrical entity?
Two entities are similar if a uniform scaling (enlarging or
shrinking) of one of the entities will allow one to obtain the other.
Notes
=====
This method is not intended to be used directly but rather
through the `are_similar` function found in util.py.
An entity is not required to implement this method.
If two different types of entities can be similar, it is only
required that one of them be able to determine this.
See Also
========
scale
"""
raise NotImplementedError()
def reflect(self, line):
"""
Reflects an object across a line.
Parameters
==========
line: Line
Examples
========
>>> from sympy import pi, sqrt, Line, RegularPolygon
>>> l = Line((0, pi), slope=sqrt(2))
>>> pent = RegularPolygon((1, 2), 1, 5)
>>> rpent = pent.reflect(l)
>>> rpent
RegularPolygon(Point2D(-2*sqrt(2)*pi/3 - 1/3 + 4*sqrt(2)/3, 2/3 + 2*sqrt(2)/3 + 2*pi/3), -1, 5, -atan(2*sqrt(2)) + 3*pi/5)
>>> from sympy import pi, Line, Circle, Point
>>> l = Line((0, pi), slope=1)
>>> circ = Circle(Point(0, 0), 5)
>>> rcirc = circ.reflect(l)
>>> rcirc
Circle(Point2D(-pi, pi), -5)
"""
from sympy.geometry.point import Point
g = self
l = line
o = Point(0, 0)
if l.slope.is_zero:
v = l.args[0].y
if not v: # x-axis
return g.scale(y=-1)
reps = [(p, p.translate(y=2*(v - p.y))) for p in g.atoms(Point)]
elif l.slope is oo:
v = l.args[0].x
if not v: # y-axis
return g.scale(x=-1)
reps = [(p, p.translate(x=2*(v - p.x))) for p in g.atoms(Point)]
else:
if not hasattr(g, 'reflect') and not all(
isinstance(arg, Point) for arg in g.args):
raise NotImplementedError(
'reflect undefined or non-Point args in %s' % g)
a = atan(l.slope)
c = l.coefficients
d = -c[-1]/c[1] # y-intercept
# apply the transform to a single point
xf = Point(x, y)
xf = xf.translate(y=-d).rotate(-a, o).scale(y=-1
).rotate(a, o).translate(y=d)
# replace every point using that transform
reps = [(p, xf.xreplace({x: p.x, y: p.y})) for p in g.atoms(Point)]
return g.xreplace(dict(reps))
def rotate(self, angle, pt=None):
"""Rotate ``angle`` radians counterclockwise about Point ``pt``.
The default pt is the origin, Point(0, 0)
See Also
========
scale, translate
Examples
========
>>> from sympy import Point, RegularPolygon, Polygon, pi
>>> t = Polygon(*RegularPolygon(Point(0, 0), 1, 3).vertices)
>>> t # vertex on x axis
Triangle(Point2D(1, 0), Point2D(-1/2, sqrt(3)/2), Point2D(-1/2, -sqrt(3)/2))
>>> t.rotate(pi/2) # vertex on y axis now
Triangle(Point2D(0, 1), Point2D(-sqrt(3)/2, -1/2), Point2D(sqrt(3)/2, -1/2))
"""
newargs = []
for a in self.args:
if isinstance(a, GeometryEntity):
newargs.append(a.rotate(angle, pt))
else:
newargs.append(a)
return type(self)(*newargs)
def scale(self, x=1, y=1, pt=None):
"""Scale the object by multiplying the x,y-coordinates by x and y.
If pt is given, the scaling is done relative to that point; the
object is shifted by -pt, scaled, and shifted by pt.
See Also
========
rotate, translate
Examples
========
>>> from sympy import RegularPolygon, Point, Polygon
>>> t = Polygon(*RegularPolygon(Point(0, 0), 1, 3).vertices)
>>> t
Triangle(Point2D(1, 0), Point2D(-1/2, sqrt(3)/2), Point2D(-1/2, -sqrt(3)/2))
>>> t.scale(2)
Triangle(Point2D(2, 0), Point2D(-1, sqrt(3)/2), Point2D(-1, -sqrt(3)/2))
>>> t.scale(2, 2)
Triangle(Point2D(2, 0), Point2D(-1, sqrt(3)), Point2D(-1, -sqrt(3)))
"""
from sympy.geometry.point import Point
if pt:
pt = Point(pt, dim=2)
return self.translate(*(-pt).args).scale(x, y).translate(*pt.args)
return type(self)(*[a.scale(x, y) for a in self.args]) # if this fails, override this class
def translate(self, x=0, y=0):
"""Shift the object by adding to the x,y-coordinates the values x and y.
See Also
========
rotate, scale
Examples
========
>>> from sympy import RegularPolygon, Point, Polygon
>>> t = Polygon(*RegularPolygon(Point(0, 0), 1, 3).vertices)
>>> t
Triangle(Point2D(1, 0), Point2D(-1/2, sqrt(3)/2), Point2D(-1/2, -sqrt(3)/2))
>>> t.translate(2)
Triangle(Point2D(3, 0), Point2D(3/2, sqrt(3)/2), Point2D(3/2, -sqrt(3)/2))
>>> t.translate(2, 2)
Triangle(Point2D(3, 2), Point2D(3/2, sqrt(3)/2 + 2), Point2D(3/2, 2 - sqrt(3)/2))
"""
newargs = []
for a in self.args:
if isinstance(a, GeometryEntity):
newargs.append(a.translate(x, y))
else:
newargs.append(a)
return self.func(*newargs)
def parameter_value(self, other, t):
"""Return the parameter corresponding to the given point.
Evaluating an arbitrary point of the entity at this parameter
value will return the given point.
Examples
========
>>> from sympy import Line, Point
>>> from sympy.abc import t
>>> a = Point(0, 0)
>>> b = Point(2, 2)
>>> Line(a, b).parameter_value((1, 1), t)
{t: 1/2}
>>> Line(a, b).arbitrary_point(t).subs(_)
Point2D(1, 1)
"""
from sympy.geometry.point import Point
if not isinstance(other, GeometryEntity):
other = Point(other, dim=self.ambient_dimension)
if not isinstance(other, Point):
raise ValueError("other must be a point")
sol = solve(self.arbitrary_point(T) - other, T, dict=True)
if not sol:
raise ValueError("Given point is not on %s" % func_name(self))
return {t: sol[0][T]}
class GeometrySet(GeometryEntity, Set):
"""Parent class of all GeometryEntity that are also Sets
(compatible with sympy.sets)
"""
__slots__ = ()
def _contains(self, other):
"""sympy.sets uses the _contains method, so include it for compatibility."""
if isinstance(other, Set) and other.is_FiniteSet:
return all(self.__contains__(i) for i in other)
return self.__contains__(other)
@dispatch(GeometrySet, Set) # type:ignore # noqa:F811
def union_sets(self, o): # noqa:F811
""" Returns the union of self and o
for use with sympy.sets.Set, if possible. """
# if its a FiniteSet, merge any points
# we contain and return a union with the rest
if o.is_FiniteSet:
other_points = [p for p in o if not self._contains(p)]
if len(other_points) == len(o):
return None
return Union(self, FiniteSet(*other_points))
if self._contains(o):
return self
return None
@dispatch(GeometrySet, Set) # type: ignore # noqa:F811
def intersection_sets(self, o): # noqa:F811
""" Returns a sympy.sets.Set of intersection objects,
if possible. """
from sympy.geometry.point import Point
try:
# if o is a FiniteSet, find the intersection directly
# to avoid infinite recursion
if o.is_FiniteSet:
inter = FiniteSet(*(p for p in o if self.contains(p)))
else:
inter = self.intersection(o)
except NotImplementedError:
# sympy.sets.Set.reduce expects None if an object
# doesn't know how to simplify
return None
# put the points in a FiniteSet
points = FiniteSet(*[p for p in inter if isinstance(p, Point)])
non_points = [p for p in inter if not isinstance(p, Point)]
return Union(*(non_points + [points]))
def translate(x, y):
"""Return the matrix to translate a 2-D point by x and y."""
rv = eye(3)
rv[2, 0] = x
rv[2, 1] = y
return rv
def scale(x, y, pt=None):
"""Return the matrix to multiply a 2-D point's coordinates by x and y.
If pt is given, the scaling is done relative to that point."""
rv = eye(3)
rv[0, 0] = x
rv[1, 1] = y
if pt:
from sympy.geometry.point import Point
pt = Point(pt, dim=2)
tr1 = translate(*(-pt).args)
tr2 = translate(*pt.args)
return tr1*rv*tr2
return rv
def rotate(th):
"""Return the matrix to rotate a 2-D point about the origin by ``angle``.
The angle is measured in radians. To Point a point about a point other
then the origin, translate the Point, do the rotation, and
translate it back:
>>> from sympy.geometry.entity import rotate, translate
>>> from sympy import Point, pi
>>> rot_about_11 = translate(-1, -1)*rotate(pi/2)*translate(1, 1)
>>> Point(1, 1).transform(rot_about_11)
Point2D(1, 1)
>>> Point(0, 0).transform(rot_about_11)
Point2D(2, 0)
"""
s = sin(th)
rv = eye(3)*cos(th)
rv[0, 1] = s
rv[1, 0] = -s
rv[2, 2] = 1
return rv
PK ]ZZZM���� � sympy/geometry/exceptions.py"""Geometry Errors."""
class GeometryError(ValueError):
"""An exception raised by classes in the geometry module."""
pass
PK ]ZZZ�2¯: : sympy/geometry/line.py"""Line-like geometrical entities.
Contains
========
LinearEntity
Line
Ray
Segment
LinearEntity2D
Line2D
Ray2D
Segment2D
LinearEntity3D
Line3D
Ray3D
Segment3D
"""
from sympy.core.containers import Tuple
from sympy.core.evalf import N
from sympy.core.expr import Expr
from sympy.core.numbers import Rational, oo, Float
from sympy.core.relational import Eq
from sympy.core.singleton import S
from sympy.core.sorting import ordered
from sympy.core.symbol import _symbol, Dummy, uniquely_named_symbol
from sympy.core.sympify import sympify
from sympy.functions.elementary.piecewise import Piecewise
from sympy.functions.elementary.trigonometric import (_pi_coeff, acos, tan, atan2)
from .entity import GeometryEntity, GeometrySet
from .exceptions import GeometryError
from .point import Point, Point3D
from .util import find, intersection
from sympy.logic.boolalg import And
from sympy.matrices import Matrix
from sympy.sets.sets import Intersection
from sympy.simplify.simplify import simplify
from sympy.solvers.solvers import solve
from sympy.solvers.solveset import linear_coeffs
from sympy.utilities.misc import Undecidable, filldedent
import random
t, u = [Dummy('line_dummy') for i in range(2)]
class LinearEntity(GeometrySet):
"""A base class for all linear entities (Line, Ray and Segment)
in n-dimensional Euclidean space.
Attributes
==========
ambient_dimension
direction
length
p1
p2
points
Notes
=====
This is an abstract class and is not meant to be instantiated.
See Also
========
sympy.geometry.entity.GeometryEntity
"""
def __new__(cls, p1, p2=None, **kwargs):
p1, p2 = Point._normalize_dimension(p1, p2)
if p1 == p2:
# sometimes we return a single point if we are not given two unique
# points. This is done in the specific subclass
raise ValueError(
"%s.__new__ requires two unique Points." % cls.__name__)
if len(p1) != len(p2):
raise ValueError(
"%s.__new__ requires two Points of equal dimension." % cls.__name__)
return GeometryEntity.__new__(cls, p1, p2, **kwargs)
def __contains__(self, other):
"""Return a definitive answer or else raise an error if it cannot
be determined that other is on the boundaries of self."""
result = self.contains(other)
if result is not None:
return result
else:
raise Undecidable(
"Cannot decide whether '%s' contains '%s'" % (self, other))
def _span_test(self, other):
"""Test whether the point `other` lies in the positive span of `self`.
A point x is 'in front' of a point y if x.dot(y) >= 0. Return
-1 if `other` is behind `self.p1`, 0 if `other` is `self.p1` and
and 1 if `other` is in front of `self.p1`."""
if self.p1 == other:
return 0
rel_pos = other - self.p1
d = self.direction
if d.dot(rel_pos) > 0:
return 1
return -1
@property
def ambient_dimension(self):
"""A property method that returns the dimension of LinearEntity
object.
Parameters
==========
p1 : LinearEntity
Returns
=======
dimension : integer
Examples
========
>>> from sympy import Point, Line
>>> p1, p2 = Point(0, 0), Point(1, 1)
>>> l1 = Line(p1, p2)
>>> l1.ambient_dimension
2
>>> from sympy import Point, Line
>>> p1, p2 = Point(0, 0, 0), Point(1, 1, 1)
>>> l1 = Line(p1, p2)
>>> l1.ambient_dimension
3
"""
return len(self.p1)
def angle_between(l1, l2):
"""Return the non-reflex angle formed by rays emanating from
the origin with directions the same as the direction vectors
of the linear entities.
Parameters
==========
l1 : LinearEntity
l2 : LinearEntity
Returns
=======
angle : angle in radians
Notes
=====
From the dot product of vectors v1 and v2 it is known that:
``dot(v1, v2) = |v1|*|v2|*cos(A)``
where A is the angle formed between the two vectors. We can
get the directional vectors of the two lines and readily
find the angle between the two using the above formula.
See Also
========
is_perpendicular, Ray2D.closing_angle
Examples
========
>>> from sympy import Line
>>> e = Line((0, 0), (1, 0))
>>> ne = Line((0, 0), (1, 1))
>>> sw = Line((1, 1), (0, 0))
>>> ne.angle_between(e)
pi/4
>>> sw.angle_between(e)
3*pi/4
To obtain the non-obtuse angle at the intersection of lines, use
the ``smallest_angle_between`` method:
>>> sw.smallest_angle_between(e)
pi/4
>>> from sympy import Point3D, Line3D
>>> p1, p2, p3 = Point3D(0, 0, 0), Point3D(1, 1, 1), Point3D(-1, 2, 0)
>>> l1, l2 = Line3D(p1, p2), Line3D(p2, p3)
>>> l1.angle_between(l2)
acos(-sqrt(2)/3)
>>> l1.smallest_angle_between(l2)
acos(sqrt(2)/3)
"""
if not isinstance(l1, LinearEntity) and not isinstance(l2, LinearEntity):
raise TypeError('Must pass only LinearEntity objects')
v1, v2 = l1.direction, l2.direction
return acos(v1.dot(v2)/(abs(v1)*abs(v2)))
def smallest_angle_between(l1, l2):
"""Return the smallest angle formed at the intersection of the
lines containing the linear entities.
Parameters
==========
l1 : LinearEntity
l2 : LinearEntity
Returns
=======
angle : angle in radians
Examples
========
>>> from sympy import Point, Line
>>> p1, p2, p3 = Point(0, 0), Point(0, 4), Point(2, -2)
>>> l1, l2 = Line(p1, p2), Line(p1, p3)
>>> l1.smallest_angle_between(l2)
pi/4
See Also
========
angle_between, is_perpendicular, Ray2D.closing_angle
"""
if not isinstance(l1, LinearEntity) and not isinstance(l2, LinearEntity):
raise TypeError('Must pass only LinearEntity objects')
v1, v2 = l1.direction, l2.direction
return acos(abs(v1.dot(v2))/(abs(v1)*abs(v2)))
def arbitrary_point(self, parameter='t'):
"""A parameterized point on the Line.
Parameters
==========
parameter : str, optional
The name of the parameter which will be used for the parametric
point. The default value is 't'. When this parameter is 0, the
first point used to define the line will be returned, and when
it is 1 the second point will be returned.
Returns
=======
point : Point
Raises
======
ValueError
When ``parameter`` already appears in the Line's definition.
See Also
========
sympy.geometry.point.Point
Examples
========
>>> from sympy import Point, Line
>>> p1, p2 = Point(1, 0), Point(5, 3)
>>> l1 = Line(p1, p2)
>>> l1.arbitrary_point()
Point2D(4*t + 1, 3*t)
>>> from sympy import Point3D, Line3D
>>> p1, p2 = Point3D(1, 0, 0), Point3D(5, 3, 1)
>>> l1 = Line3D(p1, p2)
>>> l1.arbitrary_point()
Point3D(4*t + 1, 3*t, t)
"""
t = _symbol(parameter, real=True)
if t.name in (f.name for f in self.free_symbols):
raise ValueError(filldedent('''
Symbol %s already appears in object
and cannot be used as a parameter.
''' % t.name))
# multiply on the right so the variable gets
# combined with the coordinates of the point
return self.p1 + (self.p2 - self.p1)*t
@staticmethod
def are_concurrent(*lines):
"""Is a sequence of linear entities concurrent?
Two or more linear entities are concurrent if they all
intersect at a single point.
Parameters
==========
lines
A sequence of linear entities.
Returns
=======
True : if the set of linear entities intersect in one point
False : otherwise.
See Also
========
sympy.geometry.util.intersection
Examples
========
>>> from sympy import Point, Line
>>> p1, p2 = Point(0, 0), Point(3, 5)
>>> p3, p4 = Point(-2, -2), Point(0, 2)
>>> l1, l2, l3 = Line(p1, p2), Line(p1, p3), Line(p1, p4)
>>> Line.are_concurrent(l1, l2, l3)
True
>>> l4 = Line(p2, p3)
>>> Line.are_concurrent(l2, l3, l4)
False
>>> from sympy import Point3D, Line3D
>>> p1, p2 = Point3D(0, 0, 0), Point3D(3, 5, 2)
>>> p3, p4 = Point3D(-2, -2, -2), Point3D(0, 2, 1)
>>> l1, l2, l3 = Line3D(p1, p2), Line3D(p1, p3), Line3D(p1, p4)
>>> Line3D.are_concurrent(l1, l2, l3)
True
>>> l4 = Line3D(p2, p3)
>>> Line3D.are_concurrent(l2, l3, l4)
False
"""
common_points = Intersection(*lines)
if common_points.is_FiniteSet and len(common_points) == 1:
return True
return False
def contains(self, other):
"""Subclasses should implement this method and should return
True if other is on the boundaries of self;
False if not on the boundaries of self;
None if a determination cannot be made."""
raise NotImplementedError()
@property
def direction(self):
"""The direction vector of the LinearEntity.
Returns
=======
p : a Point; the ray from the origin to this point is the
direction of `self`
Examples
========
>>> from sympy import Line
>>> a, b = (1, 1), (1, 3)
>>> Line(a, b).direction
Point2D(0, 2)
>>> Line(b, a).direction
Point2D(0, -2)
This can be reported so the distance from the origin is 1:
>>> Line(b, a).direction.unit
Point2D(0, -1)
See Also
========
sympy.geometry.point.Point.unit
"""
return self.p2 - self.p1
def intersection(self, other):
"""The intersection with another geometrical entity.
Parameters
==========
o : Point or LinearEntity
Returns
=======
intersection : list of geometrical entities
See Also
========
sympy.geometry.point.Point
Examples
========
>>> from sympy import Point, Line, Segment
>>> p1, p2, p3 = Point(0, 0), Point(1, 1), Point(7, 7)
>>> l1 = Line(p1, p2)
>>> l1.intersection(p3)
[Point2D(7, 7)]
>>> p4, p5 = Point(5, 0), Point(0, 3)
>>> l2 = Line(p4, p5)
>>> l1.intersection(l2)
[Point2D(15/8, 15/8)]
>>> p6, p7 = Point(0, 5), Point(2, 6)
>>> s1 = Segment(p6, p7)
>>> l1.intersection(s1)
[]
>>> from sympy import Point3D, Line3D, Segment3D
>>> p1, p2, p3 = Point3D(0, 0, 0), Point3D(1, 1, 1), Point3D(7, 7, 7)
>>> l1 = Line3D(p1, p2)
>>> l1.intersection(p3)
[Point3D(7, 7, 7)]
>>> l1 = Line3D(Point3D(4,19,12), Point3D(5,25,17))
>>> l2 = Line3D(Point3D(-3, -15, -19), direction_ratio=[2,8,8])
>>> l1.intersection(l2)
[Point3D(1, 1, -3)]
>>> p6, p7 = Point3D(0, 5, 2), Point3D(2, 6, 3)
>>> s1 = Segment3D(p6, p7)
>>> l1.intersection(s1)
[]
"""
def intersect_parallel_rays(ray1, ray2):
if ray1.direction.dot(ray2.direction) > 0:
# rays point in the same direction
# so return the one that is "in front"
return [ray2] if ray1._span_test(ray2.p1) >= 0 else [ray1]
else:
# rays point in opposite directions
st = ray1._span_test(ray2.p1)
if st < 0:
return []
elif st == 0:
return [ray2.p1]
return [Segment(ray1.p1, ray2.p1)]
def intersect_parallel_ray_and_segment(ray, seg):
st1, st2 = ray._span_test(seg.p1), ray._span_test(seg.p2)
if st1 < 0 and st2 < 0:
return []
elif st1 >= 0 and st2 >= 0:
return [seg]
elif st1 >= 0: # st2 < 0:
return [Segment(ray.p1, seg.p1)]
else: # st1 < 0 and st2 >= 0:
return [Segment(ray.p1, seg.p2)]
def intersect_parallel_segments(seg1, seg2):
if seg1.contains(seg2):
return [seg2]
if seg2.contains(seg1):
return [seg1]
# direct the segments so they're oriented the same way
if seg1.direction.dot(seg2.direction) < 0:
seg2 = Segment(seg2.p2, seg2.p1)
# order the segments so seg1 is "behind" seg2
if seg1._span_test(seg2.p1) < 0:
seg1, seg2 = seg2, seg1
if seg2._span_test(seg1.p2) < 0:
return []
return [Segment(seg2.p1, seg1.p2)]
if not isinstance(other, GeometryEntity):
other = Point(other, dim=self.ambient_dimension)
if other.is_Point:
if self.contains(other):
return [other]
else:
return []
elif isinstance(other, LinearEntity):
# break into cases based on whether
# the lines are parallel, non-parallel intersecting, or skew
pts = Point._normalize_dimension(self.p1, self.p2, other.p1, other.p2)
rank = Point.affine_rank(*pts)
if rank == 1:
# we're collinear
if isinstance(self, Line):
return [other]
if isinstance(other, Line):
return [self]
if isinstance(self, Ray) and isinstance(other, Ray):
return intersect_parallel_rays(self, other)
if isinstance(self, Ray) and isinstance(other, Segment):
return intersect_parallel_ray_and_segment(self, other)
if isinstance(self, Segment) and isinstance(other, Ray):
return intersect_parallel_ray_and_segment(other, self)
if isinstance(self, Segment) and isinstance(other, Segment):
return intersect_parallel_segments(self, other)
elif rank == 2:
# we're in the same plane
l1 = Line(*pts[:2])
l2 = Line(*pts[2:])
# check to see if we're parallel. If we are, we can't
# be intersecting, since the collinear case was already
# handled
if l1.direction.is_scalar_multiple(l2.direction):
return []
# find the intersection as if everything were lines
# by solving the equation t*d + p1 == s*d' + p1'
m = Matrix([l1.direction, -l2.direction]).transpose()
v = Matrix([l2.p1 - l1.p1]).transpose()
# we cannot use m.solve(v) because that only works for square matrices
m_rref, pivots = m.col_insert(2, v).rref(simplify=True)
# rank == 2 ensures we have 2 pivots, but let's check anyway
if len(pivots) != 2:
raise GeometryError("Failed when solving Mx=b when M={} and b={}".format(m, v))
coeff = m_rref[0, 2]
line_intersection = l1.direction*coeff + self.p1
# if both are lines, skip a containment check
if isinstance(self, Line) and isinstance(other, Line):
return [line_intersection]
if ((isinstance(self, Line) or
self.contains(line_intersection)) and
other.contains(line_intersection)):
return [line_intersection]
if not self.atoms(Float) and not other.atoms(Float):
# if it can fail when there are no Floats then
# maybe the following parametric check should be
# done
return []
# floats may fail exact containment so check that the
# arbitrary points, when equal, both give a
# non-negative parameter when the arbitrary point
# coordinates are equated
tu = solve(self.arbitrary_point(t) - other.arbitrary_point(u),
t, u, dict=True)[0]
def ok(p, l):
if isinstance(l, Line):
# p > -oo
return True
if isinstance(l, Ray):
# p >= 0
return p.is_nonnegative
if isinstance(l, Segment):
# 0 <= p <= 1
return p.is_nonnegative and (1 - p).is_nonnegative
raise ValueError("unexpected line type")
if ok(tu[t], self) and ok(tu[u], other):
return [line_intersection]
return []
else:
# we're skew
return []
return other.intersection(self)
def is_parallel(l1, l2):
"""Are two linear entities parallel?
Parameters
==========
l1 : LinearEntity
l2 : LinearEntity
Returns
=======
True : if l1 and l2 are parallel,
False : otherwise.
See Also
========
coefficients
Examples
========
>>> from sympy import Point, Line
>>> p1, p2 = Point(0, 0), Point(1, 1)
>>> p3, p4 = Point(3, 4), Point(6, 7)
>>> l1, l2 = Line(p1, p2), Line(p3, p4)
>>> Line.is_parallel(l1, l2)
True
>>> p5 = Point(6, 6)
>>> l3 = Line(p3, p5)
>>> Line.is_parallel(l1, l3)
False
>>> from sympy import Point3D, Line3D
>>> p1, p2 = Point3D(0, 0, 0), Point3D(3, 4, 5)
>>> p3, p4 = Point3D(2, 1, 1), Point3D(8, 9, 11)
>>> l1, l2 = Line3D(p1, p2), Line3D(p3, p4)
>>> Line3D.is_parallel(l1, l2)
True
>>> p5 = Point3D(6, 6, 6)
>>> l3 = Line3D(p3, p5)
>>> Line3D.is_parallel(l1, l3)
False
"""
if not isinstance(l1, LinearEntity) and not isinstance(l2, LinearEntity):
raise TypeError('Must pass only LinearEntity objects')
return l1.direction.is_scalar_multiple(l2.direction)
def is_perpendicular(l1, l2):
"""Are two linear entities perpendicular?
Parameters
==========
l1 : LinearEntity
l2 : LinearEntity
Returns
=======
True : if l1 and l2 are perpendicular,
False : otherwise.
See Also
========
coefficients
Examples
========
>>> from sympy import Point, Line
>>> p1, p2, p3 = Point(0, 0), Point(1, 1), Point(-1, 1)
>>> l1, l2 = Line(p1, p2), Line(p1, p3)
>>> l1.is_perpendicular(l2)
True
>>> p4 = Point(5, 3)
>>> l3 = Line(p1, p4)
>>> l1.is_perpendicular(l3)
False
>>> from sympy import Point3D, Line3D
>>> p1, p2, p3 = Point3D(0, 0, 0), Point3D(1, 1, 1), Point3D(-1, 2, 0)
>>> l1, l2 = Line3D(p1, p2), Line3D(p2, p3)
>>> l1.is_perpendicular(l2)
False
>>> p4 = Point3D(5, 3, 7)
>>> l3 = Line3D(p1, p4)
>>> l1.is_perpendicular(l3)
False
"""
if not isinstance(l1, LinearEntity) and not isinstance(l2, LinearEntity):
raise TypeError('Must pass only LinearEntity objects')
return S.Zero.equals(l1.direction.dot(l2.direction))
def is_similar(self, other):
"""
Return True if self and other are contained in the same line.
Examples
========
>>> from sympy import Point, Line
>>> p1, p2, p3 = Point(0, 1), Point(3, 4), Point(2, 3)
>>> l1 = Line(p1, p2)
>>> l2 = Line(p1, p3)
>>> l1.is_similar(l2)
True
"""
l = Line(self.p1, self.p2)
return l.contains(other)
@property
def length(self):
"""
The length of the line.
Examples
========
>>> from sympy import Point, Line
>>> p1, p2 = Point(0, 0), Point(3, 5)
>>> l1 = Line(p1, p2)
>>> l1.length
oo
"""
return S.Infinity
@property
def p1(self):
"""The first defining point of a linear entity.
See Also
========
sympy.geometry.point.Point
Examples
========
>>> from sympy import Point, Line
>>> p1, p2 = Point(0, 0), Point(5, 3)
>>> l = Line(p1, p2)
>>> l.p1
Point2D(0, 0)
"""
return self.args[0]
@property
def p2(self):
"""The second defining point of a linear entity.
See Also
========
sympy.geometry.point.Point
Examples
========
>>> from sympy import Point, Line
>>> p1, p2 = Point(0, 0), Point(5, 3)
>>> l = Line(p1, p2)
>>> l.p2
Point2D(5, 3)
"""
return self.args[1]
def parallel_line(self, p):
"""Create a new Line parallel to this linear entity which passes
through the point `p`.
Parameters
==========
p : Point
Returns
=======
line : Line
See Also
========
is_parallel
Examples
========
>>> from sympy import Point, Line
>>> p1, p2, p3 = Point(0, 0), Point(2, 3), Point(-2, 2)
>>> l1 = Line(p1, p2)
>>> l2 = l1.parallel_line(p3)
>>> p3 in l2
True
>>> l1.is_parallel(l2)
True
>>> from sympy import Point3D, Line3D
>>> p1, p2, p3 = Point3D(0, 0, 0), Point3D(2, 3, 4), Point3D(-2, 2, 0)
>>> l1 = Line3D(p1, p2)
>>> l2 = l1.parallel_line(p3)
>>> p3 in l2
True
>>> l1.is_parallel(l2)
True
"""
p = Point(p, dim=self.ambient_dimension)
return Line(p, p + self.direction)
def perpendicular_line(self, p):
"""Create a new Line perpendicular to this linear entity which passes
through the point `p`.
Parameters
==========
p : Point
Returns
=======
line : Line
See Also
========
sympy.geometry.line.LinearEntity.is_perpendicular, perpendicular_segment
Examples
========
>>> from sympy import Point3D, Line3D
>>> p1, p2, p3 = Point3D(0, 0, 0), Point3D(2, 3, 4), Point3D(-2, 2, 0)
>>> L = Line3D(p1, p2)
>>> P = L.perpendicular_line(p3); P
Line3D(Point3D(-2, 2, 0), Point3D(4/29, 6/29, 8/29))
>>> L.is_perpendicular(P)
True
In 3D the, the first point used to define the line is the point
through which the perpendicular was required to pass; the
second point is (arbitrarily) contained in the given line:
>>> P.p2 in L
True
"""
p = Point(p, dim=self.ambient_dimension)
if p in self:
p = p + self.direction.orthogonal_direction
return Line(p, self.projection(p))
def perpendicular_segment(self, p):
"""Create a perpendicular line segment from `p` to this line.
The endpoints of the segment are ``p`` and the closest point in
the line containing self. (If self is not a line, the point might
not be in self.)
Parameters
==========
p : Point
Returns
=======
segment : Segment
Notes
=====
Returns `p` itself if `p` is on this linear entity.
See Also
========
perpendicular_line
Examples
========
>>> from sympy import Point, Line
>>> p1, p2, p3 = Point(0, 0), Point(1, 1), Point(0, 2)
>>> l1 = Line(p1, p2)
>>> s1 = l1.perpendicular_segment(p3)
>>> l1.is_perpendicular(s1)
True
>>> p3 in s1
True
>>> l1.perpendicular_segment(Point(4, 0))
Segment2D(Point2D(4, 0), Point2D(2, 2))
>>> from sympy import Point3D, Line3D
>>> p1, p2, p3 = Point3D(0, 0, 0), Point3D(1, 1, 1), Point3D(0, 2, 0)
>>> l1 = Line3D(p1, p2)
>>> s1 = l1.perpendicular_segment(p3)
>>> l1.is_perpendicular(s1)
True
>>> p3 in s1
True
>>> l1.perpendicular_segment(Point3D(4, 0, 0))
Segment3D(Point3D(4, 0, 0), Point3D(4/3, 4/3, 4/3))
"""
p = Point(p, dim=self.ambient_dimension)
if p in self:
return p
l = self.perpendicular_line(p)
# The intersection should be unique, so unpack the singleton
p2, = Intersection(Line(self.p1, self.p2), l)
return Segment(p, p2)
@property
def points(self):
"""The two points used to define this linear entity.
Returns
=======
points : tuple of Points
See Also
========
sympy.geometry.point.Point
Examples
========
>>> from sympy import Point, Line
>>> p1, p2 = Point(0, 0), Point(5, 11)
>>> l1 = Line(p1, p2)
>>> l1.points
(Point2D(0, 0), Point2D(5, 11))
"""
return (self.p1, self.p2)
def projection(self, other):
"""Project a point, line, ray, or segment onto this linear entity.
Parameters
==========
other : Point or LinearEntity (Line, Ray, Segment)
Returns
=======
projection : Point or LinearEntity (Line, Ray, Segment)
The return type matches the type of the parameter ``other``.
Raises
======
GeometryError
When method is unable to perform projection.
Notes
=====
A projection involves taking the two points that define
the linear entity and projecting those points onto a
Line and then reforming the linear entity using these
projections.
A point P is projected onto a line L by finding the point
on L that is closest to P. This point is the intersection
of L and the line perpendicular to L that passes through P.
See Also
========
sympy.geometry.point.Point, perpendicular_line
Examples
========
>>> from sympy import Point, Line, Segment, Rational
>>> p1, p2, p3 = Point(0, 0), Point(1, 1), Point(Rational(1, 2), 0)
>>> l1 = Line(p1, p2)
>>> l1.projection(p3)
Point2D(1/4, 1/4)
>>> p4, p5 = Point(10, 0), Point(12, 1)
>>> s1 = Segment(p4, p5)
>>> l1.projection(s1)
Segment2D(Point2D(5, 5), Point2D(13/2, 13/2))
>>> p1, p2, p3 = Point(0, 0, 1), Point(1, 1, 2), Point(2, 0, 1)
>>> l1 = Line(p1, p2)
>>> l1.projection(p3)
Point3D(2/3, 2/3, 5/3)
>>> p4, p5 = Point(10, 0, 1), Point(12, 1, 3)
>>> s1 = Segment(p4, p5)
>>> l1.projection(s1)
Segment3D(Point3D(10/3, 10/3, 13/3), Point3D(5, 5, 6))
"""
if not isinstance(other, GeometryEntity):
other = Point(other, dim=self.ambient_dimension)
def proj_point(p):
return Point.project(p - self.p1, self.direction) + self.p1
if isinstance(other, Point):
return proj_point(other)
elif isinstance(other, LinearEntity):
p1, p2 = proj_point(other.p1), proj_point(other.p2)
# test to see if we're degenerate
if p1 == p2:
return p1
projected = other.__class__(p1, p2)
projected = Intersection(self, projected)
if projected.is_empty:
return projected
# if we happen to have intersected in only a point, return that
if projected.is_FiniteSet and len(projected) == 1:
# projected is a set of size 1, so unpack it in `a`
a, = projected
return a
# order args so projection is in the same direction as self
if self.direction.dot(projected.direction) < 0:
p1, p2 = projected.args
projected = projected.func(p2, p1)
return projected
raise GeometryError(
"Do not know how to project %s onto %s" % (other, self))
def random_point(self, seed=None):
"""A random point on a LinearEntity.
Returns
=======
point : Point
See Also
========
sympy.geometry.point.Point
Examples
========
>>> from sympy import Point, Line, Ray, Segment
>>> p1, p2 = Point(0, 0), Point(5, 3)
>>> line = Line(p1, p2)
>>> r = line.random_point(seed=42) # seed value is optional
>>> r.n(3)
Point2D(-0.72, -0.432)
>>> r in line
True
>>> Ray(p1, p2).random_point(seed=42).n(3)
Point2D(0.72, 0.432)
>>> Segment(p1, p2).random_point(seed=42).n(3)
Point2D(3.2, 1.92)
"""
if seed is not None:
rng = random.Random(seed)
else:
rng = random
pt = self.arbitrary_point(t)
if isinstance(self, Ray):
v = abs(rng.gauss(0, 1))
elif isinstance(self, Segment):
v = rng.random()
elif isinstance(self, Line):
v = rng.gauss(0, 1)
else:
raise NotImplementedError('unhandled line type')
return pt.subs(t, Rational(v))
def bisectors(self, other):
"""Returns the perpendicular lines which pass through the intersections
of self and other that are in the same plane.
Parameters
==========
line : Line3D
Returns
=======
list: two Line instances
Examples
========
>>> from sympy import Point3D, Line3D
>>> r1 = Line3D(Point3D(0, 0, 0), Point3D(1, 0, 0))
>>> r2 = Line3D(Point3D(0, 0, 0), Point3D(0, 1, 0))
>>> r1.bisectors(r2)
[Line3D(Point3D(0, 0, 0), Point3D(1, 1, 0)), Line3D(Point3D(0, 0, 0), Point3D(1, -1, 0))]
"""
if not isinstance(other, LinearEntity):
raise GeometryError("Expecting LinearEntity, not %s" % other)
l1, l2 = self, other
# make sure dimensions match or else a warning will rise from
# intersection calculation
if l1.p1.ambient_dimension != l2.p1.ambient_dimension:
if isinstance(l1, Line2D):
l1, l2 = l2, l1
_, p1 = Point._normalize_dimension(l1.p1, l2.p1, on_morph='ignore')
_, p2 = Point._normalize_dimension(l1.p2, l2.p2, on_morph='ignore')
l2 = Line(p1, p2)
point = intersection(l1, l2)
# Three cases: Lines may intersect in a point, may be equal or may not intersect.
if not point:
raise GeometryError("The lines do not intersect")
else:
pt = point[0]
if isinstance(pt, Line):
# Intersection is a line because both lines are coincident
return [self]
d1 = l1.direction.unit
d2 = l2.direction.unit
bis1 = Line(pt, pt + d1 + d2)
bis2 = Line(pt, pt + d1 - d2)
return [bis1, bis2]
class Line(LinearEntity):
"""An infinite line in space.
A 2D line is declared with two distinct points, point and slope, or
an equation. A 3D line may be defined with a point and a direction ratio.
Parameters
==========
p1 : Point
p2 : Point
slope : SymPy expression
direction_ratio : list
equation : equation of a line
Notes
=====
`Line` will automatically subclass to `Line2D` or `Line3D` based
on the dimension of `p1`. The `slope` argument is only relevant
for `Line2D` and the `direction_ratio` argument is only relevant
for `Line3D`.
The order of the points will define the direction of the line
which is used when calculating the angle between lines.
See Also
========
sympy.geometry.point.Point
sympy.geometry.line.Line2D
sympy.geometry.line.Line3D
Examples
========
>>> from sympy import Line, Segment, Point, Eq
>>> from sympy.abc import x, y, a, b
>>> L = Line(Point(2,3), Point(3,5))
>>> L
Line2D(Point2D(2, 3), Point2D(3, 5))
>>> L.points
(Point2D(2, 3), Point2D(3, 5))
>>> L.equation()
-2*x + y + 1
>>> L.coefficients
(-2, 1, 1)
Instantiate with keyword ``slope``:
>>> Line(Point(0, 0), slope=0)
Line2D(Point2D(0, 0), Point2D(1, 0))
Instantiate with another linear object
>>> s = Segment((0, 0), (0, 1))
>>> Line(s).equation()
x
The line corresponding to an equation in the for `ax + by + c = 0`,
can be entered:
>>> Line(3*x + y + 18)
Line2D(Point2D(0, -18), Point2D(1, -21))
If `x` or `y` has a different name, then they can be specified, too,
as a string (to match the name) or symbol:
>>> Line(Eq(3*a + b, -18), x='a', y=b)
Line2D(Point2D(0, -18), Point2D(1, -21))
"""
def __new__(cls, *args, **kwargs):
if len(args) == 1 and isinstance(args[0], (Expr, Eq)):
missing = uniquely_named_symbol('?', args)
if not kwargs:
x = 'x'
y = 'y'
else:
x = kwargs.pop('x', missing)
y = kwargs.pop('y', missing)
if kwargs:
raise ValueError('expecting only x and y as keywords')
equation = args[0]
if isinstance(equation, Eq):
equation = equation.lhs - equation.rhs
def find_or_missing(x):
try:
return find(x, equation)
except ValueError:
return missing
x = find_or_missing(x)
y = find_or_missing(y)
a, b, c = linear_coeffs(equation, x, y)
if b:
return Line((0, -c/b), slope=-a/b)
if a:
return Line((-c/a, 0), slope=oo)
raise ValueError('not found in equation: %s' % (set('xy') - {x, y}))
else:
if len(args) > 0:
p1 = args[0]
if len(args) > 1:
p2 = args[1]
else:
p2 = None
if isinstance(p1, LinearEntity):
if p2:
raise ValueError('If p1 is a LinearEntity, p2 must be None.')
dim = len(p1.p1)
else:
p1 = Point(p1)
dim = len(p1)
if p2 is not None or isinstance(p2, Point) and p2.ambient_dimension != dim:
p2 = Point(p2)
if dim == 2:
return Line2D(p1, p2, **kwargs)
elif dim == 3:
return Line3D(p1, p2, **kwargs)
return LinearEntity.__new__(cls, p1, p2, **kwargs)
def contains(self, other):
"""
Return True if `other` is on this Line, or False otherwise.
Examples
========
>>> from sympy import Line,Point
>>> p1, p2 = Point(0, 1), Point(3, 4)
>>> l = Line(p1, p2)
>>> l.contains(p1)
True
>>> l.contains((0, 1))
True
>>> l.contains((0, 0))
False
>>> a = (0, 0, 0)
>>> b = (1, 1, 1)
>>> c = (2, 2, 2)
>>> l1 = Line(a, b)
>>> l2 = Line(b, a)
>>> l1 == l2
False
>>> l1 in l2
True
"""
if not isinstance(other, GeometryEntity):
other = Point(other, dim=self.ambient_dimension)
if isinstance(other, Point):
return Point.is_collinear(other, self.p1, self.p2)
if isinstance(other, LinearEntity):
return Point.is_collinear(self.p1, self.p2, other.p1, other.p2)
return False
def distance(self, other):
"""
Finds the shortest distance between a line and a point.
Raises
======
NotImplementedError is raised if `other` is not a Point
Examples
========
>>> from sympy import Point, Line
>>> p1, p2 = Point(0, 0), Point(1, 1)
>>> s = Line(p1, p2)
>>> s.distance(Point(-1, 1))
sqrt(2)
>>> s.distance((-1, 2))
3*sqrt(2)/2
>>> p1, p2 = Point(0, 0, 0), Point(1, 1, 1)
>>> s = Line(p1, p2)
>>> s.distance(Point(-1, 1, 1))
2*sqrt(6)/3
>>> s.distance((-1, 1, 1))
2*sqrt(6)/3
"""
if not isinstance(other, GeometryEntity):
other = Point(other, dim=self.ambient_dimension)
if self.contains(other):
return S.Zero
return self.perpendicular_segment(other).length
def equals(self, other):
"""Returns True if self and other are the same mathematical entities"""
if not isinstance(other, Line):
return False
return Point.is_collinear(self.p1, other.p1, self.p2, other.p2)
def plot_interval(self, parameter='t'):
"""The plot interval for the default geometric plot of line. Gives
values that will produce a line that is +/- 5 units long (where a
unit is the distance between the two points that define the line).
Parameters
==========
parameter : str, optional
Default value is 't'.
Returns
=======
plot_interval : list (plot interval)
[parameter, lower_bound, upper_bound]
Examples
========
>>> from sympy import Point, Line
>>> p1, p2 = Point(0, 0), Point(5, 3)
>>> l1 = Line(p1, p2)
>>> l1.plot_interval()
[t, -5, 5]
"""
t = _symbol(parameter, real=True)
return [t, -5, 5]
class Ray(LinearEntity):
"""A Ray is a semi-line in the space with a source point and a direction.
Parameters
==========
p1 : Point
The source of the Ray
p2 : Point or radian value
This point determines the direction in which the Ray propagates.
If given as an angle it is interpreted in radians with the positive
direction being ccw.
Attributes
==========
source
See Also
========
sympy.geometry.line.Ray2D
sympy.geometry.line.Ray3D
sympy.geometry.point.Point
sympy.geometry.line.Line
Notes
=====
`Ray` will automatically subclass to `Ray2D` or `Ray3D` based on the
dimension of `p1`.
Examples
========
>>> from sympy import Ray, Point, pi
>>> r = Ray(Point(2, 3), Point(3, 5))
>>> r
Ray2D(Point2D(2, 3), Point2D(3, 5))
>>> r.points
(Point2D(2, 3), Point2D(3, 5))
>>> r.source
Point2D(2, 3)
>>> r.xdirection
oo
>>> r.ydirection
oo
>>> r.slope
2
>>> Ray(Point(0, 0), angle=pi/4).slope
1
"""
def __new__(cls, p1, p2=None, **kwargs):
p1 = Point(p1)
if p2 is not None:
p1, p2 = Point._normalize_dimension(p1, Point(p2))
dim = len(p1)
if dim == 2:
return Ray2D(p1, p2, **kwargs)
elif dim == 3:
return Ray3D(p1, p2, **kwargs)
return LinearEntity.__new__(cls, p1, p2, **kwargs)
def _svg(self, scale_factor=1., fill_color="#66cc99"):
"""Returns SVG path element for the LinearEntity.
Parameters
==========
scale_factor : float
Multiplication factor for the SVG stroke-width. Default is 1.
fill_color : str, optional
Hex string for fill color. Default is "#66cc99".
"""
verts = (N(self.p1), N(self.p2))
coords = ["{},{}".format(p.x, p.y) for p in verts]
path = "M {} L {}".format(coords[0], " L ".join(coords[1:]))
return (
'<path fill-rule="evenodd" fill="{2}" stroke="#555555" '
'stroke-width="{0}" opacity="0.6" d="{1}" '
'marker-start="url(#markerCircle)" marker-end="url(#markerArrow)"/>'
).format(2.*scale_factor, path, fill_color)
def contains(self, other):
"""
Is other GeometryEntity contained in this Ray?
Examples
========
>>> from sympy import Ray,Point,Segment
>>> p1, p2 = Point(0, 0), Point(4, 4)
>>> r = Ray(p1, p2)
>>> r.contains(p1)
True
>>> r.contains((1, 1))
True
>>> r.contains((1, 3))
False
>>> s = Segment((1, 1), (2, 2))
>>> r.contains(s)
True
>>> s = Segment((1, 2), (2, 5))
>>> r.contains(s)
False
>>> r1 = Ray((2, 2), (3, 3))
>>> r.contains(r1)
True
>>> r1 = Ray((2, 2), (3, 5))
>>> r.contains(r1)
False
"""
if not isinstance(other, GeometryEntity):
other = Point(other, dim=self.ambient_dimension)
if isinstance(other, Point):
if Point.is_collinear(self.p1, self.p2, other):
# if we're in the direction of the ray, our
# direction vector dot the ray's direction vector
# should be non-negative
return bool((self.p2 - self.p1).dot(other - self.p1) >= S.Zero)
return False
elif isinstance(other, Ray):
if Point.is_collinear(self.p1, self.p2, other.p1, other.p2):
return bool((self.p2 - self.p1).dot(other.p2 - other.p1) > S.Zero)
return False
elif isinstance(other, Segment):
return other.p1 in self and other.p2 in self
# No other known entity can be contained in a Ray
return False
def distance(self, other):
"""
Finds the shortest distance between the ray and a point.
Raises
======
NotImplementedError is raised if `other` is not a Point
Examples
========
>>> from sympy import Point, Ray
>>> p1, p2 = Point(0, 0), Point(1, 1)
>>> s = Ray(p1, p2)
>>> s.distance(Point(-1, -1))
sqrt(2)
>>> s.distance((-1, 2))
3*sqrt(2)/2
>>> p1, p2 = Point(0, 0, 0), Point(1, 1, 2)
>>> s = Ray(p1, p2)
>>> s
Ray3D(Point3D(0, 0, 0), Point3D(1, 1, 2))
>>> s.distance(Point(-1, -1, 2))
4*sqrt(3)/3
>>> s.distance((-1, -1, 2))
4*sqrt(3)/3
"""
if not isinstance(other, GeometryEntity):
other = Point(other, dim=self.ambient_dimension)
if self.contains(other):
return S.Zero
proj = Line(self.p1, self.p2).projection(other)
if self.contains(proj):
return abs(other - proj)
else:
return abs(other - self.source)
def equals(self, other):
"""Returns True if self and other are the same mathematical entities"""
if not isinstance(other, Ray):
return False
return self.source == other.source and other.p2 in self
def plot_interval(self, parameter='t'):
"""The plot interval for the default geometric plot of the Ray. Gives
values that will produce a ray that is 10 units long (where a unit is
the distance between the two points that define the ray).
Parameters
==========
parameter : str, optional
Default value is 't'.
Returns
=======
plot_interval : list
[parameter, lower_bound, upper_bound]
Examples
========
>>> from sympy import Ray, pi
>>> r = Ray((0, 0), angle=pi/4)
>>> r.plot_interval()
[t, 0, 10]
"""
t = _symbol(parameter, real=True)
return [t, 0, 10]
@property
def source(self):
"""The point from which the ray emanates.
See Also
========
sympy.geometry.point.Point
Examples
========
>>> from sympy import Point, Ray
>>> p1, p2 = Point(0, 0), Point(4, 1)
>>> r1 = Ray(p1, p2)
>>> r1.source
Point2D(0, 0)
>>> p1, p2 = Point(0, 0, 0), Point(4, 1, 5)
>>> r1 = Ray(p2, p1)
>>> r1.source
Point3D(4, 1, 5)
"""
return self.p1
class Segment(LinearEntity):
"""A line segment in space.
Parameters
==========
p1 : Point
p2 : Point
Attributes
==========
length : number or SymPy expression
midpoint : Point
See Also
========
sympy.geometry.line.Segment2D
sympy.geometry.line.Segment3D
sympy.geometry.point.Point
sympy.geometry.line.Line
Notes
=====
If 2D or 3D points are used to define `Segment`, it will
be automatically subclassed to `Segment2D` or `Segment3D`.
Examples
========
>>> from sympy import Point, Segment
>>> Segment((1, 0), (1, 1)) # tuples are interpreted as pts
Segment2D(Point2D(1, 0), Point2D(1, 1))
>>> s = Segment(Point(4, 3), Point(1, 1))
>>> s.points
(Point2D(4, 3), Point2D(1, 1))
>>> s.slope
2/3
>>> s.length
sqrt(13)
>>> s.midpoint
Point2D(5/2, 2)
>>> Segment((1, 0, 0), (1, 1, 1)) # tuples are interpreted as pts
Segment3D(Point3D(1, 0, 0), Point3D(1, 1, 1))
>>> s = Segment(Point(4, 3, 9), Point(1, 1, 7)); s
Segment3D(Point3D(4, 3, 9), Point3D(1, 1, 7))
>>> s.points
(Point3D(4, 3, 9), Point3D(1, 1, 7))
>>> s.length
sqrt(17)
>>> s.midpoint
Point3D(5/2, 2, 8)
"""
def __new__(cls, p1, p2, **kwargs):
p1, p2 = Point._normalize_dimension(Point(p1), Point(p2))
dim = len(p1)
if dim == 2:
return Segment2D(p1, p2, **kwargs)
elif dim == 3:
return Segment3D(p1, p2, **kwargs)
return LinearEntity.__new__(cls, p1, p2, **kwargs)
def contains(self, other):
"""
Is the other GeometryEntity contained within this Segment?
Examples
========
>>> from sympy import Point, Segment
>>> p1, p2 = Point(0, 1), Point(3, 4)
>>> s = Segment(p1, p2)
>>> s2 = Segment(p2, p1)
>>> s.contains(s2)
True
>>> from sympy import Point3D, Segment3D
>>> p1, p2 = Point3D(0, 1, 1), Point3D(3, 4, 5)
>>> s = Segment3D(p1, p2)
>>> s2 = Segment3D(p2, p1)
>>> s.contains(s2)
True
>>> s.contains((p1 + p2)/2)
True
"""
if not isinstance(other, GeometryEntity):
other = Point(other, dim=self.ambient_dimension)
if isinstance(other, Point):
if Point.is_collinear(other, self.p1, self.p2):
if isinstance(self, Segment2D):
# if it is collinear and is in the bounding box of the
# segment then it must be on the segment
vert = (1/self.slope).equals(0)
if vert is False:
isin = (self.p1.x - other.x)*(self.p2.x - other.x) <= 0
if isin in (True, False):
return isin
if vert is True:
isin = (self.p1.y - other.y)*(self.p2.y - other.y) <= 0
if isin in (True, False):
return isin
# use the triangle inequality
d1, d2 = other - self.p1, other - self.p2
d = self.p2 - self.p1
# without the call to simplify, SymPy cannot tell that an expression
# like (a+b)*(a/2+b/2) is always non-negative. If it cannot be
# determined, raise an Undecidable error
try:
# the triangle inequality says that |d1|+|d2| >= |d| and is strict
# only if other lies in the line segment
return bool(simplify(Eq(abs(d1) + abs(d2) - abs(d), 0)))
except TypeError:
raise Undecidable("Cannot determine if {} is in {}".format(other, self))
if isinstance(other, Segment):
return other.p1 in self and other.p2 in self
return False
def equals(self, other):
"""Returns True if self and other are the same mathematical entities"""
return isinstance(other, self.func) and list(
ordered(self.args)) == list(ordered(other.args))
def distance(self, other):
"""
Finds the shortest distance between a line segment and a point.
Raises
======
NotImplementedError is raised if `other` is not a Point
Examples
========
>>> from sympy import Point, Segment
>>> p1, p2 = Point(0, 1), Point(3, 4)
>>> s = Segment(p1, p2)
>>> s.distance(Point(10, 15))
sqrt(170)
>>> s.distance((0, 12))
sqrt(73)
>>> from sympy import Point3D, Segment3D
>>> p1, p2 = Point3D(0, 0, 3), Point3D(1, 1, 4)
>>> s = Segment3D(p1, p2)
>>> s.distance(Point3D(10, 15, 12))
sqrt(341)
>>> s.distance((10, 15, 12))
sqrt(341)
"""
if not isinstance(other, GeometryEntity):
other = Point(other, dim=self.ambient_dimension)
if isinstance(other, Point):
vp1 = other - self.p1
vp2 = other - self.p2
dot_prod_sign_1 = self.direction.dot(vp1) >= 0
dot_prod_sign_2 = self.direction.dot(vp2) <= 0
if dot_prod_sign_1 and dot_prod_sign_2:
return Line(self.p1, self.p2).distance(other)
if dot_prod_sign_1 and not dot_prod_sign_2:
return abs(vp2)
if not dot_prod_sign_1 and dot_prod_sign_2:
return abs(vp1)
raise NotImplementedError()
@property
def length(self):
"""The length of the line segment.
See Also
========
sympy.geometry.point.Point.distance
Examples
========
>>> from sympy import Point, Segment
>>> p1, p2 = Point(0, 0), Point(4, 3)
>>> s1 = Segment(p1, p2)
>>> s1.length
5
>>> from sympy import Point3D, Segment3D
>>> p1, p2 = Point3D(0, 0, 0), Point3D(4, 3, 3)
>>> s1 = Segment3D(p1, p2)
>>> s1.length
sqrt(34)
"""
return Point.distance(self.p1, self.p2)
@property
def midpoint(self):
"""The midpoint of the line segment.
See Also
========
sympy.geometry.point.Point.midpoint
Examples
========
>>> from sympy import Point, Segment
>>> p1, p2 = Point(0, 0), Point(4, 3)
>>> s1 = Segment(p1, p2)
>>> s1.midpoint
Point2D(2, 3/2)
>>> from sympy import Point3D, Segment3D
>>> p1, p2 = Point3D(0, 0, 0), Point3D(4, 3, 3)
>>> s1 = Segment3D(p1, p2)
>>> s1.midpoint
Point3D(2, 3/2, 3/2)
"""
return Point.midpoint(self.p1, self.p2)
def perpendicular_bisector(self, p=None):
"""The perpendicular bisector of this segment.
If no point is specified or the point specified is not on the
bisector then the bisector is returned as a Line. Otherwise a
Segment is returned that joins the point specified and the
intersection of the bisector and the segment.
Parameters
==========
p : Point
Returns
=======
bisector : Line or Segment
See Also
========
LinearEntity.perpendicular_segment
Examples
========
>>> from sympy import Point, Segment
>>> p1, p2, p3 = Point(0, 0), Point(6, 6), Point(5, 1)
>>> s1 = Segment(p1, p2)
>>> s1.perpendicular_bisector()
Line2D(Point2D(3, 3), Point2D(-3, 9))
>>> s1.perpendicular_bisector(p3)
Segment2D(Point2D(5, 1), Point2D(3, 3))
"""
l = self.perpendicular_line(self.midpoint)
if p is not None:
p2 = Point(p, dim=self.ambient_dimension)
if p2 in l:
return Segment(p2, self.midpoint)
return l
def plot_interval(self, parameter='t'):
"""The plot interval for the default geometric plot of the Segment gives
values that will produce the full segment in a plot.
Parameters
==========
parameter : str, optional
Default value is 't'.
Returns
=======
plot_interval : list
[parameter, lower_bound, upper_bound]
Examples
========
>>> from sympy import Point, Segment
>>> p1, p2 = Point(0, 0), Point(5, 3)
>>> s1 = Segment(p1, p2)
>>> s1.plot_interval()
[t, 0, 1]
"""
t = _symbol(parameter, real=True)
return [t, 0, 1]
class LinearEntity2D(LinearEntity):
"""A base class for all linear entities (line, ray and segment)
in a 2-dimensional Euclidean space.
Attributes
==========
p1
p2
coefficients
slope
points
Notes
=====
This is an abstract class and is not meant to be instantiated.
See Also
========
sympy.geometry.entity.GeometryEntity
"""
@property
def bounds(self):
"""Return a tuple (xmin, ymin, xmax, ymax) representing the bounding
rectangle for the geometric figure.
"""
verts = self.points
xs = [p.x for p in verts]
ys = [p.y for p in verts]
return (min(xs), min(ys), max(xs), max(ys))
def perpendicular_line(self, p):
"""Create a new Line perpendicular to this linear entity which passes
through the point `p`.
Parameters
==========
p : Point
Returns
=======
line : Line
See Also
========
sympy.geometry.line.LinearEntity.is_perpendicular, perpendicular_segment
Examples
========
>>> from sympy import Point, Line
>>> p1, p2, p3 = Point(0, 0), Point(2, 3), Point(-2, 2)
>>> L = Line(p1, p2)
>>> P = L.perpendicular_line(p3); P
Line2D(Point2D(-2, 2), Point2D(-5, 4))
>>> L.is_perpendicular(P)
True
In 2D, the first point of the perpendicular line is the
point through which was required to pass; the second
point is arbitrarily chosen. To get a line that explicitly
uses a point in the line, create a line from the perpendicular
segment from the line to the point:
>>> Line(L.perpendicular_segment(p3))
Line2D(Point2D(-2, 2), Point2D(4/13, 6/13))
"""
p = Point(p, dim=self.ambient_dimension)
# any two lines in R^2 intersect, so blindly making
# a line through p in an orthogonal direction will work
# and is faster than finding the projection point as in 3D
return Line(p, p + self.direction.orthogonal_direction)
@property
def slope(self):
"""The slope of this linear entity, or infinity if vertical.
Returns
=======
slope : number or SymPy expression
See Also
========
coefficients
Examples
========
>>> from sympy import Point, Line
>>> p1, p2 = Point(0, 0), Point(3, 5)
>>> l1 = Line(p1, p2)
>>> l1.slope
5/3
>>> p3 = Point(0, 4)
>>> l2 = Line(p1, p3)
>>> l2.slope
oo
"""
d1, d2 = (self.p1 - self.p2).args
if d1 == 0:
return S.Infinity
return simplify(d2/d1)
class Line2D(LinearEntity2D, Line):
"""An infinite line in space 2D.
A line is declared with two distinct points or a point and slope
as defined using keyword `slope`.
Parameters
==========
p1 : Point
pt : Point
slope : SymPy expression
See Also
========
sympy.geometry.point.Point
Examples
========
>>> from sympy import Line, Segment, Point
>>> L = Line(Point(2,3), Point(3,5))
>>> L
Line2D(Point2D(2, 3), Point2D(3, 5))
>>> L.points
(Point2D(2, 3), Point2D(3, 5))
>>> L.equation()
-2*x + y + 1
>>> L.coefficients
(-2, 1, 1)
Instantiate with keyword ``slope``:
>>> Line(Point(0, 0), slope=0)
Line2D(Point2D(0, 0), Point2D(1, 0))
Instantiate with another linear object
>>> s = Segment((0, 0), (0, 1))
>>> Line(s).equation()
x
"""
def __new__(cls, p1, pt=None, slope=None, **kwargs):
if isinstance(p1, LinearEntity):
if pt is not None:
raise ValueError('When p1 is a LinearEntity, pt should be None')
p1, pt = Point._normalize_dimension(*p1.args, dim=2)
else:
p1 = Point(p1, dim=2)
if pt is not None and slope is None:
try:
p2 = Point(pt, dim=2)
except (NotImplementedError, TypeError, ValueError):
raise ValueError(filldedent('''
The 2nd argument was not a valid Point.
If it was a slope, enter it with keyword "slope".
'''))
elif slope is not None and pt is None:
slope = sympify(slope)
if slope.is_finite is False:
# when infinite slope, don't change x
dx = 0
dy = 1
else:
# go over 1 up slope
dx = 1
dy = slope
# XXX avoiding simplification by adding to coords directly
p2 = Point(p1.x + dx, p1.y + dy, evaluate=False)
else:
raise ValueError('A 2nd Point or keyword "slope" must be used.')
return LinearEntity2D.__new__(cls, p1, p2, **kwargs)
def _svg(self, scale_factor=1., fill_color="#66cc99"):
"""Returns SVG path element for the LinearEntity.
Parameters
==========
scale_factor : float
Multiplication factor for the SVG stroke-width. Default is 1.
fill_color : str, optional
Hex string for fill color. Default is "#66cc99".
"""
verts = (N(self.p1), N(self.p2))
coords = ["{},{}".format(p.x, p.y) for p in verts]
path = "M {} L {}".format(coords[0], " L ".join(coords[1:]))
return (
'<path fill-rule="evenodd" fill="{2}" stroke="#555555" '
'stroke-width="{0}" opacity="0.6" d="{1}" '
'marker-start="url(#markerReverseArrow)" marker-end="url(#markerArrow)"/>'
).format(2.*scale_factor, path, fill_color)
@property
def coefficients(self):
"""The coefficients (`a`, `b`, `c`) for `ax + by + c = 0`.
See Also
========
sympy.geometry.line.Line2D.equation
Examples
========
>>> from sympy import Point, Line
>>> from sympy.abc import x, y
>>> p1, p2 = Point(0, 0), Point(5, 3)
>>> l = Line(p1, p2)
>>> l.coefficients
(-3, 5, 0)
>>> p3 = Point(x, y)
>>> l2 = Line(p1, p3)
>>> l2.coefficients
(-y, x, 0)
"""
p1, p2 = self.points
if p1.x == p2.x:
return (S.One, S.Zero, -p1.x)
elif p1.y == p2.y:
return (S.Zero, S.One, -p1.y)
return tuple([simplify(i) for i in
(self.p1.y - self.p2.y,
self.p2.x - self.p1.x,
self.p1.x*self.p2.y - self.p1.y*self.p2.x)])
def equation(self, x='x', y='y'):
"""The equation of the line: ax + by + c.
Parameters
==========
x : str, optional
The name to use for the x-axis, default value is 'x'.
y : str, optional
The name to use for the y-axis, default value is 'y'.
Returns
=======
equation : SymPy expression
See Also
========
sympy.geometry.line.Line2D.coefficients
Examples
========
>>> from sympy import Point, Line
>>> p1, p2 = Point(1, 0), Point(5, 3)
>>> l1 = Line(p1, p2)
>>> l1.equation()
-3*x + 4*y + 3
"""
x = _symbol(x, real=True)
y = _symbol(y, real=True)
p1, p2 = self.points
if p1.x == p2.x:
return x - p1.x
elif p1.y == p2.y:
return y - p1.y
a, b, c = self.coefficients
return a*x + b*y + c
class Ray2D(LinearEntity2D, Ray):
"""
A Ray is a semi-line in the space with a source point and a direction.
Parameters
==========
p1 : Point
The source of the Ray
p2 : Point or radian value
This point determines the direction in which the Ray propagates.
If given as an angle it is interpreted in radians with the positive
direction being ccw.
Attributes
==========
source
xdirection
ydirection
See Also
========
sympy.geometry.point.Point, Line
Examples
========
>>> from sympy import Point, pi, Ray
>>> r = Ray(Point(2, 3), Point(3, 5))
>>> r
Ray2D(Point2D(2, 3), Point2D(3, 5))
>>> r.points
(Point2D(2, 3), Point2D(3, 5))
>>> r.source
Point2D(2, 3)
>>> r.xdirection
oo
>>> r.ydirection
oo
>>> r.slope
2
>>> Ray(Point(0, 0), angle=pi/4).slope
1
"""
def __new__(cls, p1, pt=None, angle=None, **kwargs):
p1 = Point(p1, dim=2)
if pt is not None and angle is None:
try:
p2 = Point(pt, dim=2)
except (NotImplementedError, TypeError, ValueError):
raise ValueError(filldedent('''
The 2nd argument was not a valid Point; if
it was meant to be an angle it should be
given with keyword "angle".'''))
if p1 == p2:
raise ValueError('A Ray requires two distinct points.')
elif angle is not None and pt is None:
# we need to know if the angle is an odd multiple of pi/2
angle = sympify(angle)
c = _pi_coeff(angle)
p2 = None
if c is not None:
if c.is_Rational:
if c.q == 2:
if c.p == 1:
p2 = p1 + Point(0, 1)
elif c.p == 3:
p2 = p1 + Point(0, -1)
elif c.q == 1:
if c.p == 0:
p2 = p1 + Point(1, 0)
elif c.p == 1:
p2 = p1 + Point(-1, 0)
if p2 is None:
c *= S.Pi
else:
c = angle % (2*S.Pi)
if not p2:
m = 2*c/S.Pi
left = And(1 < m, m < 3) # is it in quadrant 2 or 3?
x = Piecewise((-1, left), (Piecewise((0, Eq(m % 1, 0)), (1, True)), True))
y = Piecewise((-tan(c), left), (Piecewise((1, Eq(m, 1)), (-1, Eq(m, 3)), (tan(c), True)), True))
p2 = p1 + Point(x, y)
else:
raise ValueError('A 2nd point or keyword "angle" must be used.')
return LinearEntity2D.__new__(cls, p1, p2, **kwargs)
@property
def xdirection(self):
"""The x direction of the ray.
Positive infinity if the ray points in the positive x direction,
negative infinity if the ray points in the negative x direction,
or 0 if the ray is vertical.
See Also
========
ydirection
Examples
========
>>> from sympy import Point, Ray
>>> p1, p2, p3 = Point(0, 0), Point(1, 1), Point(0, -1)
>>> r1, r2 = Ray(p1, p2), Ray(p1, p3)
>>> r1.xdirection
oo
>>> r2.xdirection
0
"""
if self.p1.x < self.p2.x:
return S.Infinity
elif self.p1.x == self.p2.x:
return S.Zero
else:
return S.NegativeInfinity
@property
def ydirection(self):
"""The y direction of the ray.
Positive infinity if the ray points in the positive y direction,
negative infinity if the ray points in the negative y direction,
or 0 if the ray is horizontal.
See Also
========
xdirection
Examples
========
>>> from sympy import Point, Ray
>>> p1, p2, p3 = Point(0, 0), Point(-1, -1), Point(-1, 0)
>>> r1, r2 = Ray(p1, p2), Ray(p1, p3)
>>> r1.ydirection
-oo
>>> r2.ydirection
0
"""
if self.p1.y < self.p2.y:
return S.Infinity
elif self.p1.y == self.p2.y:
return S.Zero
else:
return S.NegativeInfinity
def closing_angle(r1, r2):
"""Return the angle by which r2 must be rotated so it faces the same
direction as r1.
Parameters
==========
r1 : Ray2D
r2 : Ray2D
Returns
=======
angle : angle in radians (ccw angle is positive)
See Also
========
LinearEntity.angle_between
Examples
========
>>> from sympy import Ray, pi
>>> r1 = Ray((0, 0), (1, 0))
>>> r2 = r1.rotate(-pi/2)
>>> angle = r1.closing_angle(r2); angle
pi/2
>>> r2.rotate(angle).direction.unit == r1.direction.unit
True
>>> r2.closing_angle(r1)
-pi/2
"""
if not all(isinstance(r, Ray2D) for r in (r1, r2)):
# although the direction property is defined for
# all linear entities, only the Ray is truly a
# directed object
raise TypeError('Both arguments must be Ray2D objects.')
a1 = atan2(*list(reversed(r1.direction.args)))
a2 = atan2(*list(reversed(r2.direction.args)))
if a1*a2 < 0:
a1 = 2*S.Pi + a1 if a1 < 0 else a1
a2 = 2*S.Pi + a2 if a2 < 0 else a2
return a1 - a2
class Segment2D(LinearEntity2D, Segment):
"""A line segment in 2D space.
Parameters
==========
p1 : Point
p2 : Point
Attributes
==========
length : number or SymPy expression
midpoint : Point
See Also
========
sympy.geometry.point.Point, Line
Examples
========
>>> from sympy import Point, Segment
>>> Segment((1, 0), (1, 1)) # tuples are interpreted as pts
Segment2D(Point2D(1, 0), Point2D(1, 1))
>>> s = Segment(Point(4, 3), Point(1, 1)); s
Segment2D(Point2D(4, 3), Point2D(1, 1))
>>> s.points
(Point2D(4, 3), Point2D(1, 1))
>>> s.slope
2/3
>>> s.length
sqrt(13)
>>> s.midpoint
Point2D(5/2, 2)
"""
def __new__(cls, p1, p2, **kwargs):
p1 = Point(p1, dim=2)
p2 = Point(p2, dim=2)
if p1 == p2:
return p1
return LinearEntity2D.__new__(cls, p1, p2, **kwargs)
def _svg(self, scale_factor=1., fill_color="#66cc99"):
"""Returns SVG path element for the LinearEntity.
Parameters
==========
scale_factor : float
Multiplication factor for the SVG stroke-width. Default is 1.
fill_color : str, optional
Hex string for fill color. Default is "#66cc99".
"""
verts = (N(self.p1), N(self.p2))
coords = ["{},{}".format(p.x, p.y) for p in verts]
path = "M {} L {}".format(coords[0], " L ".join(coords[1:]))
return (
'<path fill-rule="evenodd" fill="{2}" stroke="#555555" '
'stroke-width="{0}" opacity="0.6" d="{1}" />'
).format(2.*scale_factor, path, fill_color)
class LinearEntity3D(LinearEntity):
"""An base class for all linear entities (line, ray and segment)
in a 3-dimensional Euclidean space.
Attributes
==========
p1
p2
direction_ratio
direction_cosine
points
Notes
=====
This is a base class and is not meant to be instantiated.
"""
def __new__(cls, p1, p2, **kwargs):
p1 = Point3D(p1, dim=3)
p2 = Point3D(p2, dim=3)
if p1 == p2:
# if it makes sense to return a Point, handle in subclass
raise ValueError(
"%s.__new__ requires two unique Points." % cls.__name__)
return GeometryEntity.__new__(cls, p1, p2, **kwargs)
ambient_dimension = 3
@property
def direction_ratio(self):
"""The direction ratio of a given line in 3D.
See Also
========
sympy.geometry.line.Line3D.equation
Examples
========
>>> from sympy import Point3D, Line3D
>>> p1, p2 = Point3D(0, 0, 0), Point3D(5, 3, 1)
>>> l = Line3D(p1, p2)
>>> l.direction_ratio
[5, 3, 1]
"""
p1, p2 = self.points
return p1.direction_ratio(p2)
@property
def direction_cosine(self):
"""The normalized direction ratio of a given line in 3D.
See Also
========
sympy.geometry.line.Line3D.equation
Examples
========
>>> from sympy import Point3D, Line3D
>>> p1, p2 = Point3D(0, 0, 0), Point3D(5, 3, 1)
>>> l = Line3D(p1, p2)
>>> l.direction_cosine
[sqrt(35)/7, 3*sqrt(35)/35, sqrt(35)/35]
>>> sum(i**2 for i in _)
1
"""
p1, p2 = self.points
return p1.direction_cosine(p2)
class Line3D(LinearEntity3D, Line):
"""An infinite 3D line in space.
A line is declared with two distinct points or a point and direction_ratio
as defined using keyword `direction_ratio`.
Parameters
==========
p1 : Point3D
pt : Point3D
direction_ratio : list
See Also
========
sympy.geometry.point.Point3D
sympy.geometry.line.Line
sympy.geometry.line.Line2D
Examples
========
>>> from sympy import Line3D, Point3D
>>> L = Line3D(Point3D(2, 3, 4), Point3D(3, 5, 1))
>>> L
Line3D(Point3D(2, 3, 4), Point3D(3, 5, 1))
>>> L.points
(Point3D(2, 3, 4), Point3D(3, 5, 1))
"""
def __new__(cls, p1, pt=None, direction_ratio=(), **kwargs):
if isinstance(p1, LinearEntity3D):
if pt is not None:
raise ValueError('if p1 is a LinearEntity, pt must be None.')
p1, pt = p1.args
else:
p1 = Point(p1, dim=3)
if pt is not None and len(direction_ratio) == 0:
pt = Point(pt, dim=3)
elif len(direction_ratio) == 3 and pt is None:
pt = Point3D(p1.x + direction_ratio[0], p1.y + direction_ratio[1],
p1.z + direction_ratio[2])
else:
raise ValueError('A 2nd Point or keyword "direction_ratio" must '
'be used.')
return LinearEntity3D.__new__(cls, p1, pt, **kwargs)
def equation(self, x='x', y='y', z='z'):
"""Return the equations that define the line in 3D.
Parameters
==========
x : str, optional
The name to use for the x-axis, default value is 'x'.
y : str, optional
The name to use for the y-axis, default value is 'y'.
z : str, optional
The name to use for the z-axis, default value is 'z'.
Returns
=======
equation : Tuple of simultaneous equations
Examples
========
>>> from sympy import Point3D, Line3D, solve
>>> from sympy.abc import x, y, z
>>> p1, p2 = Point3D(1, 0, 0), Point3D(5, 3, 0)
>>> l1 = Line3D(p1, p2)
>>> eq = l1.equation(x, y, z); eq
(-3*x + 4*y + 3, z)
>>> solve(eq.subs(z, 0), (x, y, z))
{x: 4*y/3 + 1}
"""
x, y, z, k = [_symbol(i, real=True) for i in (x, y, z, 'k')]
p1, p2 = self.points
d1, d2, d3 = p1.direction_ratio(p2)
x1, y1, z1 = p1
eqs = [-d1*k + x - x1, -d2*k + y - y1, -d3*k + z - z1]
# eliminate k from equations by solving first eq with k for k
for i, e in enumerate(eqs):
if e.has(k):
kk = solve(eqs[i], k)[0]
eqs.pop(i)
break
return Tuple(*[i.subs(k, kk).as_numer_denom()[0] for i in eqs])
def distance(self, other):
"""
Finds the shortest distance between a line and another object.
Parameters
==========
Point3D, Line3D, Plane, tuple, list
Returns
=======
distance
Notes
=====
This method accepts only 3D entities as it's parameter
Tuples and lists are converted to Point3D and therefore must be of
length 3, 2 or 1.
NotImplementedError is raised if `other` is not an instance of one
of the specified classes: Point3D, Line3D, or Plane.
Examples
========
>>> from sympy.geometry import Line3D
>>> l1 = Line3D((0, 0, 0), (0, 0, 1))
>>> l2 = Line3D((0, 1, 0), (1, 1, 1))
>>> l1.distance(l2)
1
The computed distance may be symbolic, too:
>>> from sympy.abc import x, y
>>> l1 = Line3D((0, 0, 0), (0, 0, 1))
>>> l2 = Line3D((0, x, 0), (y, x, 1))
>>> l1.distance(l2)
Abs(x*y)/Abs(sqrt(y**2))
"""
from .plane import Plane # Avoid circular import
if isinstance(other, (tuple, list)):
try:
other = Point3D(other)
except ValueError:
pass
if isinstance(other, Point3D):
return super().distance(other)
if isinstance(other, Line3D):
if self == other:
return S.Zero
if self.is_parallel(other):
return super().distance(other.p1)
# Skew lines
self_direction = Matrix(self.direction_ratio)
other_direction = Matrix(other.direction_ratio)
normal = self_direction.cross(other_direction)
plane_through_self = Plane(p1=self.p1, normal_vector=normal)
return other.p1.distance(plane_through_self)
if isinstance(other, Plane):
return other.distance(self)
msg = f"{other} has type {type(other)}, which is unsupported"
raise NotImplementedError(msg)
class Ray3D(LinearEntity3D, Ray):
"""
A Ray is a semi-line in the space with a source point and a direction.
Parameters
==========
p1 : Point3D
The source of the Ray
p2 : Point or a direction vector
direction_ratio: Determines the direction in which the Ray propagates.
Attributes
==========
source
xdirection
ydirection
zdirection
See Also
========
sympy.geometry.point.Point3D, Line3D
Examples
========
>>> from sympy import Point3D, Ray3D
>>> r = Ray3D(Point3D(2, 3, 4), Point3D(3, 5, 0))
>>> r
Ray3D(Point3D(2, 3, 4), Point3D(3, 5, 0))
>>> r.points
(Point3D(2, 3, 4), Point3D(3, 5, 0))
>>> r.source
Point3D(2, 3, 4)
>>> r.xdirection
oo
>>> r.ydirection
oo
>>> r.direction_ratio
[1, 2, -4]
"""
def __new__(cls, p1, pt=None, direction_ratio=(), **kwargs):
if isinstance(p1, LinearEntity3D):
if pt is not None:
raise ValueError('If p1 is a LinearEntity, pt must be None')
p1, pt = p1.args
else:
p1 = Point(p1, dim=3)
if pt is not None and len(direction_ratio) == 0:
pt = Point(pt, dim=3)
elif len(direction_ratio) == 3 and pt is None:
pt = Point3D(p1.x + direction_ratio[0], p1.y + direction_ratio[1],
p1.z + direction_ratio[2])
else:
raise ValueError(filldedent('''
A 2nd Point or keyword "direction_ratio" must be used.
'''))
return LinearEntity3D.__new__(cls, p1, pt, **kwargs)
@property
def xdirection(self):
"""The x direction of the ray.
Positive infinity if the ray points in the positive x direction,
negative infinity if the ray points in the negative x direction,
or 0 if the ray is vertical.
See Also
========
ydirection
Examples
========
>>> from sympy import Point3D, Ray3D
>>> p1, p2, p3 = Point3D(0, 0, 0), Point3D(1, 1, 1), Point3D(0, -1, 0)
>>> r1, r2 = Ray3D(p1, p2), Ray3D(p1, p3)
>>> r1.xdirection
oo
>>> r2.xdirection
0
"""
if self.p1.x < self.p2.x:
return S.Infinity
elif self.p1.x == self.p2.x:
return S.Zero
else:
return S.NegativeInfinity
@property
def ydirection(self):
"""The y direction of the ray.
Positive infinity if the ray points in the positive y direction,
negative infinity if the ray points in the negative y direction,
or 0 if the ray is horizontal.
See Also
========
xdirection
Examples
========
>>> from sympy import Point3D, Ray3D
>>> p1, p2, p3 = Point3D(0, 0, 0), Point3D(-1, -1, -1), Point3D(-1, 0, 0)
>>> r1, r2 = Ray3D(p1, p2), Ray3D(p1, p3)
>>> r1.ydirection
-oo
>>> r2.ydirection
0
"""
if self.p1.y < self.p2.y:
return S.Infinity
elif self.p1.y == self.p2.y:
return S.Zero
else:
return S.NegativeInfinity
@property
def zdirection(self):
"""The z direction of the ray.
Positive infinity if the ray points in the positive z direction,
negative infinity if the ray points in the negative z direction,
or 0 if the ray is horizontal.
See Also
========
xdirection
Examples
========
>>> from sympy import Point3D, Ray3D
>>> p1, p2, p3 = Point3D(0, 0, 0), Point3D(-1, -1, -1), Point3D(-1, 0, 0)
>>> r1, r2 = Ray3D(p1, p2), Ray3D(p1, p3)
>>> r1.ydirection
-oo
>>> r2.ydirection
0
>>> r2.zdirection
0
"""
if self.p1.z < self.p2.z:
return S.Infinity
elif self.p1.z == self.p2.z:
return S.Zero
else:
return S.NegativeInfinity
class Segment3D(LinearEntity3D, Segment):
"""A line segment in a 3D space.
Parameters
==========
p1 : Point3D
p2 : Point3D
Attributes
==========
length : number or SymPy expression
midpoint : Point3D
See Also
========
sympy.geometry.point.Point3D, Line3D
Examples
========
>>> from sympy import Point3D, Segment3D
>>> Segment3D((1, 0, 0), (1, 1, 1)) # tuples are interpreted as pts
Segment3D(Point3D(1, 0, 0), Point3D(1, 1, 1))
>>> s = Segment3D(Point3D(4, 3, 9), Point3D(1, 1, 7)); s
Segment3D(Point3D(4, 3, 9), Point3D(1, 1, 7))
>>> s.points
(Point3D(4, 3, 9), Point3D(1, 1, 7))
>>> s.length
sqrt(17)
>>> s.midpoint
Point3D(5/2, 2, 8)
"""
def __new__(cls, p1, p2, **kwargs):
p1 = Point(p1, dim=3)
p2 = Point(p2, dim=3)
if p1 == p2:
return p1
return LinearEntity3D.__new__(cls, p1, p2, **kwargs)
PK ]ZZZg����) �) sympy/geometry/parabola.py"""Parabolic geometrical entity.
Contains
* Parabola
"""
from sympy.core import S
from sympy.core.sorting import ordered
from sympy.core.symbol import _symbol, symbols
from sympy.geometry.entity import GeometryEntity, GeometrySet
from sympy.geometry.point import Point, Point2D
from sympy.geometry.line import Line, Line2D, Ray2D, Segment2D, LinearEntity3D
from sympy.geometry.ellipse import Ellipse
from sympy.functions import sign
from sympy.simplify import simplify
from sympy.solvers.solvers import solve
class Parabola(GeometrySet):
"""A parabolic GeometryEntity.
A parabola is declared with a point, that is called 'focus', and
a line, that is called 'directrix'.
Only vertical or horizontal parabolas are currently supported.
Parameters
==========
focus : Point
Default value is Point(0, 0)
directrix : Line
Attributes
==========
focus
directrix
axis of symmetry
focal length
p parameter
vertex
eccentricity
Raises
======
ValueError
When `focus` is not a two dimensional point.
When `focus` is a point of directrix.
NotImplementedError
When `directrix` is neither horizontal nor vertical.
Examples
========
>>> from sympy import Parabola, Point, Line
>>> p1 = Parabola(Point(0, 0), Line(Point(5, 8), Point(7,8)))
>>> p1.focus
Point2D(0, 0)
>>> p1.directrix
Line2D(Point2D(5, 8), Point2D(7, 8))
"""
def __new__(cls, focus=None, directrix=None, **kwargs):
if focus:
focus = Point(focus, dim=2)
else:
focus = Point(0, 0)
directrix = Line(directrix)
if directrix.contains(focus):
raise ValueError('The focus must not be a point of directrix')
return GeometryEntity.__new__(cls, focus, directrix, **kwargs)
@property
def ambient_dimension(self):
"""Returns the ambient dimension of parabola.
Returns
=======
ambient_dimension : integer
Examples
========
>>> from sympy import Parabola, Point, Line
>>> f1 = Point(0, 0)
>>> p1 = Parabola(f1, Line(Point(5, 8), Point(7, 8)))
>>> p1.ambient_dimension
2
"""
return 2
@property
def axis_of_symmetry(self):
"""Return the axis of symmetry of the parabola: a line
perpendicular to the directrix passing through the focus.
Returns
=======
axis_of_symmetry : Line
See Also
========
sympy.geometry.line.Line
Examples
========
>>> from sympy import Parabola, Point, Line
>>> p1 = Parabola(Point(0, 0), Line(Point(5, 8), Point(7, 8)))
>>> p1.axis_of_symmetry
Line2D(Point2D(0, 0), Point2D(0, 1))
"""
return self.directrix.perpendicular_line(self.focus)
@property
def directrix(self):
"""The directrix of the parabola.
Returns
=======
directrix : Line
See Also
========
sympy.geometry.line.Line
Examples
========
>>> from sympy import Parabola, Point, Line
>>> l1 = Line(Point(5, 8), Point(7, 8))
>>> p1 = Parabola(Point(0, 0), l1)
>>> p1.directrix
Line2D(Point2D(5, 8), Point2D(7, 8))
"""
return self.args[1]
@property
def eccentricity(self):
"""The eccentricity of the parabola.
Returns
=======
eccentricity : number
A parabola may also be characterized as a conic section with an
eccentricity of 1. As a consequence of this, all parabolas are
similar, meaning that while they can be different sizes,
they are all the same shape.
See Also
========
https://en.wikipedia.org/wiki/Parabola
Examples
========
>>> from sympy import Parabola, Point, Line
>>> p1 = Parabola(Point(0, 0), Line(Point(5, 8), Point(7, 8)))
>>> p1.eccentricity
1
Notes
-----
The eccentricity for every Parabola is 1 by definition.
"""
return S.One
def equation(self, x='x', y='y'):
"""The equation of the parabola.
Parameters
==========
x : str, optional
Label for the x-axis. Default value is 'x'.
y : str, optional
Label for the y-axis. Default value is 'y'.
Returns
=======
equation : SymPy expression
Examples
========
>>> from sympy import Parabola, Point, Line
>>> p1 = Parabola(Point(0, 0), Line(Point(5, 8), Point(7, 8)))
>>> p1.equation()
-x**2 - 16*y + 64
>>> p1.equation('f')
-f**2 - 16*y + 64
>>> p1.equation(y='z')
-x**2 - 16*z + 64
"""
x = _symbol(x, real=True)
y = _symbol(y, real=True)
m = self.directrix.slope
if m is S.Infinity:
t1 = 4 * (self.p_parameter) * (x - self.vertex.x)
t2 = (y - self.vertex.y)**2
elif m == 0:
t1 = 4 * (self.p_parameter) * (y - self.vertex.y)
t2 = (x - self.vertex.x)**2
else:
a, b = self.focus
c, d = self.directrix.coefficients[:2]
t1 = (x - a)**2 + (y - b)**2
t2 = self.directrix.equation(x, y)**2/(c**2 + d**2)
return t1 - t2
@property
def focal_length(self):
"""The focal length of the parabola.
Returns
=======
focal_lenght : number or symbolic expression
Notes
=====
The distance between the vertex and the focus
(or the vertex and directrix), measured along the axis
of symmetry, is the "focal length".
See Also
========
https://en.wikipedia.org/wiki/Parabola
Examples
========
>>> from sympy import Parabola, Point, Line
>>> p1 = Parabola(Point(0, 0), Line(Point(5, 8), Point(7, 8)))
>>> p1.focal_length
4
"""
distance = self.directrix.distance(self.focus)
focal_length = distance/2
return focal_length
@property
def focus(self):
"""The focus of the parabola.
Returns
=======
focus : Point
See Also
========
sympy.geometry.point.Point
Examples
========
>>> from sympy import Parabola, Point, Line
>>> f1 = Point(0, 0)
>>> p1 = Parabola(f1, Line(Point(5, 8), Point(7, 8)))
>>> p1.focus
Point2D(0, 0)
"""
return self.args[0]
def intersection(self, o):
"""The intersection of the parabola and another geometrical entity `o`.
Parameters
==========
o : GeometryEntity, LinearEntity
Returns
=======
intersection : list of GeometryEntity objects
Examples
========
>>> from sympy import Parabola, Point, Ellipse, Line, Segment
>>> p1 = Point(0,0)
>>> l1 = Line(Point(1, -2), Point(-1,-2))
>>> parabola1 = Parabola(p1, l1)
>>> parabola1.intersection(Ellipse(Point(0, 0), 2, 5))
[Point2D(-2, 0), Point2D(2, 0)]
>>> parabola1.intersection(Line(Point(-7, 3), Point(12, 3)))
[Point2D(-4, 3), Point2D(4, 3)]
>>> parabola1.intersection(Segment((-12, -65), (14, -68)))
[]
"""
x, y = symbols('x y', real=True)
parabola_eq = self.equation()
if isinstance(o, Parabola):
if o in self:
return [o]
else:
return list(ordered([Point(i) for i in solve(
[parabola_eq, o.equation()], [x, y], set=True)[1]]))
elif isinstance(o, Point2D):
if simplify(parabola_eq.subs([(x, o._args[0]), (y, o._args[1])])) == 0:
return [o]
else:
return []
elif isinstance(o, (Segment2D, Ray2D)):
result = solve([parabola_eq,
Line2D(o.points[0], o.points[1]).equation()],
[x, y], set=True)[1]
return list(ordered([Point2D(i) for i in result if i in o]))
elif isinstance(o, (Line2D, Ellipse)):
return list(ordered([Point2D(i) for i in solve(
[parabola_eq, o.equation()], [x, y], set=True)[1]]))
elif isinstance(o, LinearEntity3D):
raise TypeError('Entity must be two dimensional, not three dimensional')
else:
raise TypeError('Wrong type of argument were put')
@property
def p_parameter(self):
"""P is a parameter of parabola.
Returns
=======
p : number or symbolic expression
Notes
=====
The absolute value of p is the focal length. The sign on p tells
which way the parabola faces. Vertical parabolas that open up
and horizontal that open right, give a positive value for p.
Vertical parabolas that open down and horizontal that open left,
give a negative value for p.
See Also
========
https://www.sparknotes.com/math/precalc/conicsections/section2/
Examples
========
>>> from sympy import Parabola, Point, Line
>>> p1 = Parabola(Point(0, 0), Line(Point(5, 8), Point(7, 8)))
>>> p1.p_parameter
-4
"""
m = self.directrix.slope
if m is S.Infinity:
x = self.directrix.coefficients[2]
p = sign(self.focus.args[0] + x)
elif m == 0:
y = self.directrix.coefficients[2]
p = sign(self.focus.args[1] + y)
else:
d = self.directrix.projection(self.focus)
p = sign(self.focus.x - d.x)
return p * self.focal_length
@property
def vertex(self):
"""The vertex of the parabola.
Returns
=======
vertex : Point
See Also
========
sympy.geometry.point.Point
Examples
========
>>> from sympy import Parabola, Point, Line
>>> p1 = Parabola(Point(0, 0), Line(Point(5, 8), Point(7, 8)))
>>> p1.vertex
Point2D(0, 4)
"""
focus = self.focus
m = self.directrix.slope
if m is S.Infinity:
vertex = Point(focus.args[0] - self.p_parameter, focus.args[1])
elif m == 0:
vertex = Point(focus.args[0], focus.args[1] - self.p_parameter)
else:
vertex = self.axis_of_symmetry.intersection(self)[0]
return vertex
PK ]ZZZ��V�*i *i sympy/geometry/plane.py"""Geometrical Planes.
Contains
========
Plane
"""
from sympy.core import Dummy, Rational, S, Symbol
from sympy.core.symbol import _symbol
from sympy.functions.elementary.trigonometric import cos, sin, acos, asin, sqrt
from .entity import GeometryEntity
from .line import (Line, Ray, Segment, Line3D, LinearEntity, LinearEntity3D,
Ray3D, Segment3D)
from .point import Point, Point3D
from sympy.matrices import Matrix
from sympy.polys.polytools import cancel
from sympy.solvers import solve, linsolve
from sympy.utilities.iterables import uniq, is_sequence
from sympy.utilities.misc import filldedent, func_name, Undecidable
from mpmath.libmp.libmpf import prec_to_dps
import random
x, y, z, t = [Dummy('plane_dummy') for i in range(4)]
class Plane(GeometryEntity):
"""
A plane is a flat, two-dimensional surface. A plane is the two-dimensional
analogue of a point (zero-dimensions), a line (one-dimension) and a solid
(three-dimensions). A plane can generally be constructed by two types of
inputs. They are:
- three non-collinear points
- a point and the plane's normal vector
Attributes
==========
p1
normal_vector
Examples
========
>>> from sympy import Plane, Point3D
>>> Plane(Point3D(1, 1, 1), Point3D(2, 3, 4), Point3D(2, 2, 2))
Plane(Point3D(1, 1, 1), (-1, 2, -1))
>>> Plane((1, 1, 1), (2, 3, 4), (2, 2, 2))
Plane(Point3D(1, 1, 1), (-1, 2, -1))
>>> Plane(Point3D(1, 1, 1), normal_vector=(1,4,7))
Plane(Point3D(1, 1, 1), (1, 4, 7))
"""
def __new__(cls, p1, a=None, b=None, **kwargs):
p1 = Point3D(p1, dim=3)
if a and b:
p2 = Point(a, dim=3)
p3 = Point(b, dim=3)
if Point3D.are_collinear(p1, p2, p3):
raise ValueError('Enter three non-collinear points')
a = p1.direction_ratio(p2)
b = p1.direction_ratio(p3)
normal_vector = tuple(Matrix(a).cross(Matrix(b)))
else:
a = kwargs.pop('normal_vector', a)
evaluate = kwargs.get('evaluate', True)
if is_sequence(a) and len(a) == 3:
normal_vector = Point3D(a).args if evaluate else a
else:
raise ValueError(filldedent('''
Either provide 3 3D points or a point with a
normal vector expressed as a sequence of length 3'''))
if all(coord.is_zero for coord in normal_vector):
raise ValueError('Normal vector cannot be zero vector')
return GeometryEntity.__new__(cls, p1, normal_vector, **kwargs)
def __contains__(self, o):
k = self.equation(x, y, z)
if isinstance(o, (LinearEntity, LinearEntity3D)):
d = Point3D(o.arbitrary_point(t))
e = k.subs([(x, d.x), (y, d.y), (z, d.z)])
return e.equals(0)
try:
o = Point(o, dim=3, strict=True)
d = k.xreplace(dict(zip((x, y, z), o.args)))
return d.equals(0)
except TypeError:
return False
def _eval_evalf(self, prec=15, **options):
pt, tup = self.args
dps = prec_to_dps(prec)
pt = pt.evalf(n=dps, **options)
tup = tuple([i.evalf(n=dps, **options) for i in tup])
return self.func(pt, normal_vector=tup, evaluate=False)
def angle_between(self, o):
"""Angle between the plane and other geometric entity.
Parameters
==========
LinearEntity3D, Plane.
Returns
=======
angle : angle in radians
Notes
=====
This method accepts only 3D entities as it's parameter, but if you want
to calculate the angle between a 2D entity and a plane you should
first convert to a 3D entity by projecting onto a desired plane and
then proceed to calculate the angle.
Examples
========
>>> from sympy import Point3D, Line3D, Plane
>>> a = Plane(Point3D(1, 2, 2), normal_vector=(1, 2, 3))
>>> b = Line3D(Point3D(1, 3, 4), Point3D(2, 2, 2))
>>> a.angle_between(b)
-asin(sqrt(21)/6)
"""
if isinstance(o, LinearEntity3D):
a = Matrix(self.normal_vector)
b = Matrix(o.direction_ratio)
c = a.dot(b)
d = sqrt(sum(i**2 for i in self.normal_vector))
e = sqrt(sum(i**2 for i in o.direction_ratio))
return asin(c/(d*e))
if isinstance(o, Plane):
a = Matrix(self.normal_vector)
b = Matrix(o.normal_vector)
c = a.dot(b)
d = sqrt(sum(i**2 for i in self.normal_vector))
e = sqrt(sum(i**2 for i in o.normal_vector))
return acos(c/(d*e))
def arbitrary_point(self, u=None, v=None):
""" Returns an arbitrary point on the Plane. If given two
parameters, the point ranges over the entire plane. If given 1
or no parameters, returns a point with one parameter which,
when varying from 0 to 2*pi, moves the point in a circle of
radius 1 about p1 of the Plane.
Examples
========
>>> from sympy import Plane, Ray
>>> from sympy.abc import u, v, t, r
>>> p = Plane((1, 1, 1), normal_vector=(1, 0, 0))
>>> p.arbitrary_point(u, v)
Point3D(1, u + 1, v + 1)
>>> p.arbitrary_point(t)
Point3D(1, cos(t) + 1, sin(t) + 1)
While arbitrary values of u and v can move the point anywhere in
the plane, the single-parameter point can be used to construct a
ray whose arbitrary point can be located at angle t and radius
r from p.p1:
>>> Ray(p.p1, _).arbitrary_point(r)
Point3D(1, r*cos(t) + 1, r*sin(t) + 1)
Returns
=======
Point3D
"""
circle = v is None
if circle:
u = _symbol(u or 't', real=True)
else:
u = _symbol(u or 'u', real=True)
v = _symbol(v or 'v', real=True)
x, y, z = self.normal_vector
a, b, c = self.p1.args
# x1, y1, z1 is a nonzero vector parallel to the plane
if x.is_zero and y.is_zero:
x1, y1, z1 = S.One, S.Zero, S.Zero
else:
x1, y1, z1 = -y, x, S.Zero
# x2, y2, z2 is also parallel to the plane, and orthogonal to x1, y1, z1
x2, y2, z2 = tuple(Matrix((x, y, z)).cross(Matrix((x1, y1, z1))))
if circle:
x1, y1, z1 = (w/sqrt(x1**2 + y1**2 + z1**2) for w in (x1, y1, z1))
x2, y2, z2 = (w/sqrt(x2**2 + y2**2 + z2**2) for w in (x2, y2, z2))
p = Point3D(a + x1*cos(u) + x2*sin(u), \
b + y1*cos(u) + y2*sin(u), \
c + z1*cos(u) + z2*sin(u))
else:
p = Point3D(a + x1*u + x2*v, b + y1*u + y2*v, c + z1*u + z2*v)
return p
@staticmethod
def are_concurrent(*planes):
"""Is a sequence of Planes concurrent?
Two or more Planes are concurrent if their intersections
are a common line.
Parameters
==========
planes: list
Returns
=======
Boolean
Examples
========
>>> from sympy import Plane, Point3D
>>> a = Plane(Point3D(5, 0, 0), normal_vector=(1, -1, 1))
>>> b = Plane(Point3D(0, -2, 0), normal_vector=(3, 1, 1))
>>> c = Plane(Point3D(0, -1, 0), normal_vector=(5, -1, 9))
>>> Plane.are_concurrent(a, b)
True
>>> Plane.are_concurrent(a, b, c)
False
"""
planes = list(uniq(planes))
for i in planes:
if not isinstance(i, Plane):
raise ValueError('All objects should be Planes but got %s' % i.func)
if len(planes) < 2:
return False
planes = list(planes)
first = planes.pop(0)
sol = first.intersection(planes[0])
if sol == []:
return False
else:
line = sol[0]
for i in planes[1:]:
l = first.intersection(i)
if not l or l[0] not in line:
return False
return True
def distance(self, o):
"""Distance between the plane and another geometric entity.
Parameters
==========
Point3D, LinearEntity3D, Plane.
Returns
=======
distance
Notes
=====
This method accepts only 3D entities as it's parameter, but if you want
to calculate the distance between a 2D entity and a plane you should
first convert to a 3D entity by projecting onto a desired plane and
then proceed to calculate the distance.
Examples
========
>>> from sympy import Point3D, Line3D, Plane
>>> a = Plane(Point3D(1, 1, 1), normal_vector=(1, 1, 1))
>>> b = Point3D(1, 2, 3)
>>> a.distance(b)
sqrt(3)
>>> c = Line3D(Point3D(2, 3, 1), Point3D(1, 2, 2))
>>> a.distance(c)
0
"""
if self.intersection(o) != []:
return S.Zero
if isinstance(o, (Segment3D, Ray3D)):
a, b = o.p1, o.p2
pi, = self.intersection(Line3D(a, b))
if pi in o:
return self.distance(pi)
elif a in Segment3D(pi, b):
return self.distance(a)
else:
assert isinstance(o, Segment3D) is True
return self.distance(b)
# following code handles `Point3D`, `LinearEntity3D`, `Plane`
a = o if isinstance(o, Point3D) else o.p1
n = Point3D(self.normal_vector).unit
d = (a - self.p1).dot(n)
return abs(d)
def equals(self, o):
"""
Returns True if self and o are the same mathematical entities.
Examples
========
>>> from sympy import Plane, Point3D
>>> a = Plane(Point3D(1, 2, 3), normal_vector=(1, 1, 1))
>>> b = Plane(Point3D(1, 2, 3), normal_vector=(2, 2, 2))
>>> c = Plane(Point3D(1, 2, 3), normal_vector=(-1, 4, 6))
>>> a.equals(a)
True
>>> a.equals(b)
True
>>> a.equals(c)
False
"""
if isinstance(o, Plane):
a = self.equation()
b = o.equation()
return cancel(a/b).is_constant()
else:
return False
def equation(self, x=None, y=None, z=None):
"""The equation of the Plane.
Examples
========
>>> from sympy import Point3D, Plane
>>> a = Plane(Point3D(1, 1, 2), Point3D(2, 4, 7), Point3D(3, 5, 1))
>>> a.equation()
-23*x + 11*y - 2*z + 16
>>> a = Plane(Point3D(1, 4, 2), normal_vector=(6, 6, 6))
>>> a.equation()
6*x + 6*y + 6*z - 42
"""
x, y, z = [i if i else Symbol(j, real=True) for i, j in zip((x, y, z), 'xyz')]
a = Point3D(x, y, z)
b = self.p1.direction_ratio(a)
c = self.normal_vector
return (sum(i*j for i, j in zip(b, c)))
def intersection(self, o):
""" The intersection with other geometrical entity.
Parameters
==========
Point, Point3D, LinearEntity, LinearEntity3D, Plane
Returns
=======
List
Examples
========
>>> from sympy import Point3D, Line3D, Plane
>>> a = Plane(Point3D(1, 2, 3), normal_vector=(1, 1, 1))
>>> b = Point3D(1, 2, 3)
>>> a.intersection(b)
[Point3D(1, 2, 3)]
>>> c = Line3D(Point3D(1, 4, 7), Point3D(2, 2, 2))
>>> a.intersection(c)
[Point3D(2, 2, 2)]
>>> d = Plane(Point3D(6, 0, 0), normal_vector=(2, -5, 3))
>>> e = Plane(Point3D(2, 0, 0), normal_vector=(3, 4, -3))
>>> d.intersection(e)
[Line3D(Point3D(78/23, -24/23, 0), Point3D(147/23, 321/23, 23))]
"""
if not isinstance(o, GeometryEntity):
o = Point(o, dim=3)
if isinstance(o, Point):
if o in self:
return [o]
else:
return []
if isinstance(o, (LinearEntity, LinearEntity3D)):
# recast to 3D
p1, p2 = o.p1, o.p2
if isinstance(o, Segment):
o = Segment3D(p1, p2)
elif isinstance(o, Ray):
o = Ray3D(p1, p2)
elif isinstance(o, Line):
o = Line3D(p1, p2)
else:
raise ValueError('unhandled linear entity: %s' % o.func)
if o in self:
return [o]
else:
a = Point3D(o.arbitrary_point(t))
p1, n = self.p1, Point3D(self.normal_vector)
# TODO: Replace solve with solveset, when this line is tested
c = solve((a - p1).dot(n), t)
if not c:
return []
else:
c = [i for i in c if i.is_real is not False]
if len(c) > 1:
c = [i for i in c if i.is_real]
if len(c) != 1:
raise Undecidable("not sure which point is real")
p = a.subs(t, c[0])
if p not in o:
return [] # e.g. a segment might not intersect a plane
return [p]
if isinstance(o, Plane):
if self.equals(o):
return [self]
if self.is_parallel(o):
return []
else:
x, y, z = map(Dummy, 'xyz')
a, b = Matrix([self.normal_vector]), Matrix([o.normal_vector])
c = list(a.cross(b))
d = self.equation(x, y, z)
e = o.equation(x, y, z)
result = list(linsolve([d, e], x, y, z))[0]
for i in (x, y, z): result = result.subs(i, 0)
return [Line3D(Point3D(result), direction_ratio=c)]
def is_coplanar(self, o):
""" Returns True if `o` is coplanar with self, else False.
Examples
========
>>> from sympy import Plane
>>> o = (0, 0, 0)
>>> p = Plane(o, (1, 1, 1))
>>> p2 = Plane(o, (2, 2, 2))
>>> p == p2
False
>>> p.is_coplanar(p2)
True
"""
if isinstance(o, Plane):
return not cancel(self.equation(x, y, z)/o.equation(x, y, z)).has(x, y, z)
if isinstance(o, Point3D):
return o in self
elif isinstance(o, LinearEntity3D):
return all(i in self for i in self)
elif isinstance(o, GeometryEntity): # XXX should only be handling 2D objects now
return all(i == 0 for i in self.normal_vector[:2])
def is_parallel(self, l):
"""Is the given geometric entity parallel to the plane?
Parameters
==========
LinearEntity3D or Plane
Returns
=======
Boolean
Examples
========
>>> from sympy import Plane, Point3D
>>> a = Plane(Point3D(1,4,6), normal_vector=(2, 4, 6))
>>> b = Plane(Point3D(3,1,3), normal_vector=(4, 8, 12))
>>> a.is_parallel(b)
True
"""
if isinstance(l, LinearEntity3D):
a = l.direction_ratio
b = self.normal_vector
c = sum(i*j for i, j in zip(a, b))
if c == 0:
return True
else:
return False
elif isinstance(l, Plane):
a = Matrix(l.normal_vector)
b = Matrix(self.normal_vector)
if a.cross(b).is_zero_matrix:
return True
else:
return False
def is_perpendicular(self, l):
"""Is the given geometric entity perpendicualar to the given plane?
Parameters
==========
LinearEntity3D or Plane
Returns
=======
Boolean
Examples
========
>>> from sympy import Plane, Point3D
>>> a = Plane(Point3D(1,4,6), normal_vector=(2, 4, 6))
>>> b = Plane(Point3D(2, 2, 2), normal_vector=(-1, 2, -1))
>>> a.is_perpendicular(b)
True
"""
if isinstance(l, LinearEntity3D):
a = Matrix(l.direction_ratio)
b = Matrix(self.normal_vector)
if a.cross(b).is_zero_matrix:
return True
else:
return False
elif isinstance(l, Plane):
a = Matrix(l.normal_vector)
b = Matrix(self.normal_vector)
if a.dot(b) == 0:
return True
else:
return False
else:
return False
@property
def normal_vector(self):
"""Normal vector of the given plane.
Examples
========
>>> from sympy import Point3D, Plane
>>> a = Plane(Point3D(1, 1, 1), Point3D(2, 3, 4), Point3D(2, 2, 2))
>>> a.normal_vector
(-1, 2, -1)
>>> a = Plane(Point3D(1, 1, 1), normal_vector=(1, 4, 7))
>>> a.normal_vector
(1, 4, 7)
"""
return self.args[1]
@property
def p1(self):
"""The only defining point of the plane. Others can be obtained from the
arbitrary_point method.
See Also
========
sympy.geometry.point.Point3D
Examples
========
>>> from sympy import Point3D, Plane
>>> a = Plane(Point3D(1, 1, 1), Point3D(2, 3, 4), Point3D(2, 2, 2))
>>> a.p1
Point3D(1, 1, 1)
"""
return self.args[0]
def parallel_plane(self, pt):
"""
Plane parallel to the given plane and passing through the point pt.
Parameters
==========
pt: Point3D
Returns
=======
Plane
Examples
========
>>> from sympy import Plane, Point3D
>>> a = Plane(Point3D(1, 4, 6), normal_vector=(2, 4, 6))
>>> a.parallel_plane(Point3D(2, 3, 5))
Plane(Point3D(2, 3, 5), (2, 4, 6))
"""
a = self.normal_vector
return Plane(pt, normal_vector=a)
def perpendicular_line(self, pt):
"""A line perpendicular to the given plane.
Parameters
==========
pt: Point3D
Returns
=======
Line3D
Examples
========
>>> from sympy import Plane, Point3D
>>> a = Plane(Point3D(1,4,6), normal_vector=(2, 4, 6))
>>> a.perpendicular_line(Point3D(9, 8, 7))
Line3D(Point3D(9, 8, 7), Point3D(11, 12, 13))
"""
a = self.normal_vector
return Line3D(pt, direction_ratio=a)
def perpendicular_plane(self, *pts):
"""
Return a perpendicular passing through the given points. If the
direction ratio between the points is the same as the Plane's normal
vector then, to select from the infinite number of possible planes,
a third point will be chosen on the z-axis (or the y-axis
if the normal vector is already parallel to the z-axis). If less than
two points are given they will be supplied as follows: if no point is
given then pt1 will be self.p1; if a second point is not given it will
be a point through pt1 on a line parallel to the z-axis (if the normal
is not already the z-axis, otherwise on the line parallel to the
y-axis).
Parameters
==========
pts: 0, 1 or 2 Point3D
Returns
=======
Plane
Examples
========
>>> from sympy import Plane, Point3D
>>> a, b = Point3D(0, 0, 0), Point3D(0, 1, 0)
>>> Z = (0, 0, 1)
>>> p = Plane(a, normal_vector=Z)
>>> p.perpendicular_plane(a, b)
Plane(Point3D(0, 0, 0), (1, 0, 0))
"""
if len(pts) > 2:
raise ValueError('No more than 2 pts should be provided.')
pts = list(pts)
if len(pts) == 0:
pts.append(self.p1)
if len(pts) == 1:
x, y, z = self.normal_vector
if x == y == 0:
dir = (0, 1, 0)
else:
dir = (0, 0, 1)
pts.append(pts[0] + Point3D(*dir))
p1, p2 = [Point(i, dim=3) for i in pts]
l = Line3D(p1, p2)
n = Line3D(p1, direction_ratio=self.normal_vector)
if l in n: # XXX should an error be raised instead?
# there are infinitely many perpendicular planes;
x, y, z = self.normal_vector
if x == y == 0:
# the z axis is the normal so pick a pt on the y-axis
p3 = Point3D(0, 1, 0) # case 1
else:
# else pick a pt on the z axis
p3 = Point3D(0, 0, 1) # case 2
# in case that point is already given, move it a bit
if p3 in l:
p3 *= 2 # case 3
else:
p3 = p1 + Point3D(*self.normal_vector) # case 4
return Plane(p1, p2, p3)
def projection_line(self, line):
"""Project the given line onto the plane through the normal plane
containing the line.
Parameters
==========
LinearEntity or LinearEntity3D
Returns
=======
Point3D, Line3D, Ray3D or Segment3D
Notes
=====
For the interaction between 2D and 3D lines(segments, rays), you should
convert the line to 3D by using this method. For example for finding the
intersection between a 2D and a 3D line, convert the 2D line to a 3D line
by projecting it on a required plane and then proceed to find the
intersection between those lines.
Examples
========
>>> from sympy import Plane, Line, Line3D, Point3D
>>> a = Plane(Point3D(1, 1, 1), normal_vector=(1, 1, 1))
>>> b = Line(Point3D(1, 1), Point3D(2, 2))
>>> a.projection_line(b)
Line3D(Point3D(4/3, 4/3, 1/3), Point3D(5/3, 5/3, -1/3))
>>> c = Line3D(Point3D(1, 1, 1), Point3D(2, 2, 2))
>>> a.projection_line(c)
Point3D(1, 1, 1)
"""
if not isinstance(line, (LinearEntity, LinearEntity3D)):
raise NotImplementedError('Enter a linear entity only')
a, b = self.projection(line.p1), self.projection(line.p2)
if a == b:
# projection does not imply intersection so for
# this case (line parallel to plane's normal) we
# return the projection point
return a
if isinstance(line, (Line, Line3D)):
return Line3D(a, b)
if isinstance(line, (Ray, Ray3D)):
return Ray3D(a, b)
if isinstance(line, (Segment, Segment3D)):
return Segment3D(a, b)
def projection(self, pt):
"""Project the given point onto the plane along the plane normal.
Parameters
==========
Point or Point3D
Returns
=======
Point3D
Examples
========
>>> from sympy import Plane, Point3D
>>> A = Plane(Point3D(1, 1, 2), normal_vector=(1, 1, 1))
The projection is along the normal vector direction, not the z
axis, so (1, 1) does not project to (1, 1, 2) on the plane A:
>>> b = Point3D(1, 1)
>>> A.projection(b)
Point3D(5/3, 5/3, 2/3)
>>> _ in A
True
But the point (1, 1, 2) projects to (1, 1) on the XY-plane:
>>> XY = Plane((0, 0, 0), (0, 0, 1))
>>> XY.projection((1, 1, 2))
Point3D(1, 1, 0)
"""
rv = Point(pt, dim=3)
if rv in self:
return rv
return self.intersection(Line3D(rv, rv + Point3D(self.normal_vector)))[0]
def random_point(self, seed=None):
""" Returns a random point on the Plane.
Returns
=======
Point3D
Examples
========
>>> from sympy import Plane
>>> p = Plane((1, 0, 0), normal_vector=(0, 1, 0))
>>> r = p.random_point(seed=42) # seed value is optional
>>> r.n(3)
Point3D(2.29, 0, -1.35)
The random point can be moved to lie on the circle of radius
1 centered on p1:
>>> c = p.p1 + (r - p.p1).unit
>>> c.distance(p.p1).equals(1)
True
"""
if seed is not None:
rng = random.Random(seed)
else:
rng = random
params = {
x: 2*Rational(rng.gauss(0, 1)) - 1,
y: 2*Rational(rng.gauss(0, 1)) - 1}
return self.arbitrary_point(x, y).subs(params)
def parameter_value(self, other, u, v=None):
"""Return the parameter(s) corresponding to the given point.
Examples
========
>>> from sympy import pi, Plane
>>> from sympy.abc import t, u, v
>>> p = Plane((2, 0, 0), (0, 0, 1), (0, 1, 0))
By default, the parameter value returned defines a point
that is a distance of 1 from the Plane's p1 value and
in line with the given point:
>>> on_circle = p.arbitrary_point(t).subs(t, pi/4)
>>> on_circle.distance(p.p1)
1
>>> p.parameter_value(on_circle, t)
{t: pi/4}
Moving the point twice as far from p1 does not change
the parameter value:
>>> off_circle = p.p1 + (on_circle - p.p1)*2
>>> off_circle.distance(p.p1)
2
>>> p.parameter_value(off_circle, t)
{t: pi/4}
If the 2-value parameter is desired, supply the two
parameter symbols and a replacement dictionary will
be returned:
>>> p.parameter_value(on_circle, u, v)
{u: sqrt(10)/10, v: sqrt(10)/30}
>>> p.parameter_value(off_circle, u, v)
{u: sqrt(10)/5, v: sqrt(10)/15}
"""
if not isinstance(other, GeometryEntity):
other = Point(other, dim=self.ambient_dimension)
if not isinstance(other, Point):
raise ValueError("other must be a point")
if other == self.p1:
return other
if isinstance(u, Symbol) and v is None:
delta = self.arbitrary_point(u) - self.p1
eq = delta - (other - self.p1).unit
sol = solve(eq, u, dict=True)
elif isinstance(u, Symbol) and isinstance(v, Symbol):
pt = self.arbitrary_point(u, v)
sol = solve(pt - other, (u, v), dict=True)
else:
raise ValueError('expecting 1 or 2 symbols')
if not sol:
raise ValueError("Given point is not on %s" % func_name(self))
return sol[0] # {t: tval} or {u: uval, v: vval}
@property
def ambient_dimension(self):
return self.p1.ambient_dimension
PK ]ZZZ���&,� ,� sympy/geometry/point.py"""Geometrical Points.
Contains
========
Point
Point2D
Point3D
When methods of Point require 1 or more points as arguments, they
can be passed as a sequence of coordinates or Points:
>>> from sympy import Point
>>> Point(1, 1).is_collinear((2, 2), (3, 4))
False
>>> Point(1, 1).is_collinear(Point(2, 2), Point(3, 4))
False
"""
import warnings
from sympy.core import S, sympify, Expr
from sympy.core.add import Add
from sympy.core.containers import Tuple
from sympy.core.numbers import Float
from sympy.core.parameters import global_parameters
from sympy.simplify import nsimplify, simplify
from sympy.geometry.exceptions import GeometryError
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.elementary.complexes import im
from sympy.functions.elementary.trigonometric import cos, sin
from sympy.matrices import Matrix
from sympy.matrices.expressions import Transpose
from sympy.utilities.iterables import uniq, is_sequence
from sympy.utilities.misc import filldedent, func_name, Undecidable
from .entity import GeometryEntity
from mpmath.libmp.libmpf import prec_to_dps
class Point(GeometryEntity):
"""A point in a n-dimensional Euclidean space.
Parameters
==========
coords : sequence of n-coordinate values. In the special
case where n=2 or 3, a Point2D or Point3D will be created
as appropriate.
evaluate : if `True` (default), all floats are turn into
exact types.
dim : number of coordinates the point should have. If coordinates
are unspecified, they are padded with zeros.
on_morph : indicates what should happen when the number of
coordinates of a point need to be changed by adding or
removing zeros. Possible values are `'warn'`, `'error'`, or
`ignore` (default). No warning or error is given when `*args`
is empty and `dim` is given. An error is always raised when
trying to remove nonzero coordinates.
Attributes
==========
length
origin: A `Point` representing the origin of the
appropriately-dimensioned space.
Raises
======
TypeError : When instantiating with anything but a Point or sequence
ValueError : when instantiating with a sequence with length < 2 or
when trying to reduce dimensions if keyword `on_morph='error'` is
set.
See Also
========
sympy.geometry.line.Segment : Connects two Points
Examples
========
>>> from sympy import Point
>>> from sympy.abc import x
>>> Point(1, 2, 3)
Point3D(1, 2, 3)
>>> Point([1, 2])
Point2D(1, 2)
>>> Point(0, x)
Point2D(0, x)
>>> Point(dim=4)
Point(0, 0, 0, 0)
Floats are automatically converted to Rational unless the
evaluate flag is False:
>>> Point(0.5, 0.25)
Point2D(1/2, 1/4)
>>> Point(0.5, 0.25, evaluate=False)
Point2D(0.5, 0.25)
"""
is_Point = True
def __new__(cls, *args, **kwargs):
evaluate = kwargs.get('evaluate', global_parameters.evaluate)
on_morph = kwargs.get('on_morph', 'ignore')
# unpack into coords
coords = args[0] if len(args) == 1 else args
# check args and handle quickly handle Point instances
if isinstance(coords, Point):
# even if we're mutating the dimension of a point, we
# don't reevaluate its coordinates
evaluate = False
if len(coords) == kwargs.get('dim', len(coords)):
return coords
if not is_sequence(coords):
raise TypeError(filldedent('''
Expecting sequence of coordinates, not `{}`'''
.format(func_name(coords))))
# A point where only `dim` is specified is initialized
# to zeros.
if len(coords) == 0 and kwargs.get('dim', None):
coords = (S.Zero,)*kwargs.get('dim')
coords = Tuple(*coords)
dim = kwargs.get('dim', len(coords))
if len(coords) < 2:
raise ValueError(filldedent('''
Point requires 2 or more coordinates or
keyword `dim` > 1.'''))
if len(coords) != dim:
message = ("Dimension of {} needs to be changed "
"from {} to {}.").format(coords, len(coords), dim)
if on_morph == 'ignore':
pass
elif on_morph == "error":
raise ValueError(message)
elif on_morph == 'warn':
warnings.warn(message, stacklevel=2)
else:
raise ValueError(filldedent('''
on_morph value should be 'error',
'warn' or 'ignore'.'''))
if any(coords[dim:]):
raise ValueError('Nonzero coordinates cannot be removed.')
if any(a.is_number and im(a).is_zero is False for a in coords):
raise ValueError('Imaginary coordinates are not permitted.')
if not all(isinstance(a, Expr) for a in coords):
raise TypeError('Coordinates must be valid SymPy expressions.')
# pad with zeros appropriately
coords = coords[:dim] + (S.Zero,)*(dim - len(coords))
# Turn any Floats into rationals and simplify
# any expressions before we instantiate
if evaluate:
coords = coords.xreplace({
f: simplify(nsimplify(f, rational=True))
for f in coords.atoms(Float)})
# return 2D or 3D instances
if len(coords) == 2:
kwargs['_nocheck'] = True
return Point2D(*coords, **kwargs)
elif len(coords) == 3:
kwargs['_nocheck'] = True
return Point3D(*coords, **kwargs)
# the general Point
return GeometryEntity.__new__(cls, *coords)
def __abs__(self):
"""Returns the distance between this point and the origin."""
origin = Point([0]*len(self))
return Point.distance(origin, self)
def __add__(self, other):
"""Add other to self by incrementing self's coordinates by
those of other.
Notes
=====
>>> from sympy import Point
When sequences of coordinates are passed to Point methods, they
are converted to a Point internally. This __add__ method does
not do that so if floating point values are used, a floating
point result (in terms of SymPy Floats) will be returned.
>>> Point(1, 2) + (.1, .2)
Point2D(1.1, 2.2)
If this is not desired, the `translate` method can be used or
another Point can be added:
>>> Point(1, 2).translate(.1, .2)
Point2D(11/10, 11/5)
>>> Point(1, 2) + Point(.1, .2)
Point2D(11/10, 11/5)
See Also
========
sympy.geometry.point.Point.translate
"""
try:
s, o = Point._normalize_dimension(self, Point(other, evaluate=False))
except TypeError:
raise GeometryError("Don't know how to add {} and a Point object".format(other))
coords = [simplify(a + b) for a, b in zip(s, o)]
return Point(coords, evaluate=False)
def __contains__(self, item):
return item in self.args
def __truediv__(self, divisor):
"""Divide point's coordinates by a factor."""
divisor = sympify(divisor)
coords = [simplify(x/divisor) for x in self.args]
return Point(coords, evaluate=False)
def __eq__(self, other):
if not isinstance(other, Point) or len(self.args) != len(other.args):
return False
return self.args == other.args
def __getitem__(self, key):
return self.args[key]
def __hash__(self):
return hash(self.args)
def __iter__(self):
return self.args.__iter__()
def __len__(self):
return len(self.args)
def __mul__(self, factor):
"""Multiply point's coordinates by a factor.
Notes
=====
>>> from sympy import Point
When multiplying a Point by a floating point number,
the coordinates of the Point will be changed to Floats:
>>> Point(1, 2)*0.1
Point2D(0.1, 0.2)
If this is not desired, the `scale` method can be used or
else only multiply or divide by integers:
>>> Point(1, 2).scale(1.1, 1.1)
Point2D(11/10, 11/5)
>>> Point(1, 2)*11/10
Point2D(11/10, 11/5)
See Also
========
sympy.geometry.point.Point.scale
"""
factor = sympify(factor)
coords = [simplify(x*factor) for x in self.args]
return Point(coords, evaluate=False)
def __rmul__(self, factor):
"""Multiply a factor by point's coordinates."""
return self.__mul__(factor)
def __neg__(self):
"""Negate the point."""
coords = [-x for x in self.args]
return Point(coords, evaluate=False)
def __sub__(self, other):
"""Subtract two points, or subtract a factor from this point's
coordinates."""
return self + [-x for x in other]
@classmethod
def _normalize_dimension(cls, *points, **kwargs):
"""Ensure that points have the same dimension.
By default `on_morph='warn'` is passed to the
`Point` constructor."""
# if we have a built-in ambient dimension, use it
dim = getattr(cls, '_ambient_dimension', None)
# override if we specified it
dim = kwargs.get('dim', dim)
# if no dim was given, use the highest dimensional point
if dim is None:
dim = max(i.ambient_dimension for i in points)
if all(i.ambient_dimension == dim for i in points):
return list(points)
kwargs['dim'] = dim
kwargs['on_morph'] = kwargs.get('on_morph', 'warn')
return [Point(i, **kwargs) for i in points]
@staticmethod
def affine_rank(*args):
"""The affine rank of a set of points is the dimension
of the smallest affine space containing all the points.
For example, if the points lie on a line (and are not all
the same) their affine rank is 1. If the points lie on a plane
but not a line, their affine rank is 2. By convention, the empty
set has affine rank -1."""
if len(args) == 0:
return -1
# make sure we're genuinely points
# and translate every point to the origin
points = Point._normalize_dimension(*[Point(i) for i in args])
origin = points[0]
points = [i - origin for i in points[1:]]
m = Matrix([i.args for i in points])
# XXX fragile -- what is a better way?
return m.rank(iszerofunc = lambda x:
abs(x.n(2)) < 1e-12 if x.is_number else x.is_zero)
@property
def ambient_dimension(self):
"""Number of components this point has."""
return getattr(self, '_ambient_dimension', len(self))
@classmethod
def are_coplanar(cls, *points):
"""Return True if there exists a plane in which all the points
lie. A trivial True value is returned if `len(points) < 3` or
all Points are 2-dimensional.
Parameters
==========
A set of points
Raises
======
ValueError : if less than 3 unique points are given
Returns
=======
boolean
Examples
========
>>> from sympy import Point3D
>>> p1 = Point3D(1, 2, 2)
>>> p2 = Point3D(2, 7, 2)
>>> p3 = Point3D(0, 0, 2)
>>> p4 = Point3D(1, 1, 2)
>>> Point3D.are_coplanar(p1, p2, p3, p4)
True
>>> p5 = Point3D(0, 1, 3)
>>> Point3D.are_coplanar(p1, p2, p3, p5)
False
"""
if len(points) <= 1:
return True
points = cls._normalize_dimension(*[Point(i) for i in points])
# quick exit if we are in 2D
if points[0].ambient_dimension == 2:
return True
points = list(uniq(points))
return Point.affine_rank(*points) <= 2
def distance(self, other):
"""The Euclidean distance between self and another GeometricEntity.
Returns
=======
distance : number or symbolic expression.
Raises
======
TypeError : if other is not recognized as a GeometricEntity or is a
GeometricEntity for which distance is not defined.
See Also
========
sympy.geometry.line.Segment.length
sympy.geometry.point.Point.taxicab_distance
Examples
========
>>> from sympy import Point, Line
>>> p1, p2 = Point(1, 1), Point(4, 5)
>>> l = Line((3, 1), (2, 2))
>>> p1.distance(p2)
5
>>> p1.distance(l)
sqrt(2)
The computed distance may be symbolic, too:
>>> from sympy.abc import x, y
>>> p3 = Point(x, y)
>>> p3.distance((0, 0))
sqrt(x**2 + y**2)
"""
if not isinstance(other, GeometryEntity):
try:
other = Point(other, dim=self.ambient_dimension)
except TypeError:
raise TypeError("not recognized as a GeometricEntity: %s" % type(other))
if isinstance(other, Point):
s, p = Point._normalize_dimension(self, Point(other))
return sqrt(Add(*((a - b)**2 for a, b in zip(s, p))))
distance = getattr(other, 'distance', None)
if distance is None:
raise TypeError("distance between Point and %s is not defined" % type(other))
return distance(self)
def dot(self, p):
"""Return dot product of self with another Point."""
if not is_sequence(p):
p = Point(p) # raise the error via Point
return Add(*(a*b for a, b in zip(self, p)))
def equals(self, other):
"""Returns whether the coordinates of self and other agree."""
# a point is equal to another point if all its components are equal
if not isinstance(other, Point) or len(self) != len(other):
return False
return all(a.equals(b) for a, b in zip(self, other))
def _eval_evalf(self, prec=15, **options):
"""Evaluate the coordinates of the point.
This method will, where possible, create and return a new Point
where the coordinates are evaluated as floating point numbers to
the precision indicated (default=15).
Parameters
==========
prec : int
Returns
=======
point : Point
Examples
========
>>> from sympy import Point, Rational
>>> p1 = Point(Rational(1, 2), Rational(3, 2))
>>> p1
Point2D(1/2, 3/2)
>>> p1.evalf()
Point2D(0.5, 1.5)
"""
dps = prec_to_dps(prec)
coords = [x.evalf(n=dps, **options) for x in self.args]
return Point(*coords, evaluate=False)
def intersection(self, other):
"""The intersection between this point and another GeometryEntity.
Parameters
==========
other : GeometryEntity or sequence of coordinates
Returns
=======
intersection : list of Points
Notes
=====
The return value will either be an empty list if there is no
intersection, otherwise it will contain this point.
Examples
========
>>> from sympy import Point
>>> p1, p2, p3 = Point(0, 0), Point(1, 1), Point(0, 0)
>>> p1.intersection(p2)
[]
>>> p1.intersection(p3)
[Point2D(0, 0)]
"""
if not isinstance(other, GeometryEntity):
other = Point(other)
if isinstance(other, Point):
if self == other:
return [self]
p1, p2 = Point._normalize_dimension(self, other)
if p1 == self and p1 == p2:
return [self]
return []
return other.intersection(self)
def is_collinear(self, *args):
"""Returns `True` if there exists a line
that contains `self` and `points`. Returns `False` otherwise.
A trivially True value is returned if no points are given.
Parameters
==========
args : sequence of Points
Returns
=======
is_collinear : boolean
See Also
========
sympy.geometry.line.Line
Examples
========
>>> from sympy import Point
>>> from sympy.abc import x
>>> p1, p2 = Point(0, 0), Point(1, 1)
>>> p3, p4, p5 = Point(2, 2), Point(x, x), Point(1, 2)
>>> Point.is_collinear(p1, p2, p3, p4)
True
>>> Point.is_collinear(p1, p2, p3, p5)
False
"""
points = (self,) + args
points = Point._normalize_dimension(*[Point(i) for i in points])
points = list(uniq(points))
return Point.affine_rank(*points) <= 1
def is_concyclic(self, *args):
"""Do `self` and the given sequence of points lie in a circle?
Returns True if the set of points are concyclic and
False otherwise. A trivial value of True is returned
if there are fewer than 2 other points.
Parameters
==========
args : sequence of Points
Returns
=======
is_concyclic : boolean
Examples
========
>>> from sympy import Point
Define 4 points that are on the unit circle:
>>> p1, p2, p3, p4 = Point(1, 0), (0, 1), (-1, 0), (0, -1)
>>> p1.is_concyclic() == p1.is_concyclic(p2, p3, p4) == True
True
Define a point not on that circle:
>>> p = Point(1, 1)
>>> p.is_concyclic(p1, p2, p3)
False
"""
points = (self,) + args
points = Point._normalize_dimension(*[Point(i) for i in points])
points = list(uniq(points))
if not Point.affine_rank(*points) <= 2:
return False
origin = points[0]
points = [p - origin for p in points]
# points are concyclic if they are coplanar and
# there is a point c so that ||p_i-c|| == ||p_j-c|| for all
# i and j. Rearranging this equation gives us the following
# condition: the matrix `mat` must not a pivot in the last
# column.
mat = Matrix([list(i) + [i.dot(i)] for i in points])
rref, pivots = mat.rref()
if len(origin) not in pivots:
return True
return False
@property
def is_nonzero(self):
"""True if any coordinate is nonzero, False if every coordinate is zero,
and None if it cannot be determined."""
is_zero = self.is_zero
if is_zero is None:
return None
return not is_zero
def is_scalar_multiple(self, p):
"""Returns whether each coordinate of `self` is a scalar
multiple of the corresponding coordinate in point p.
"""
s, o = Point._normalize_dimension(self, Point(p))
# 2d points happen a lot, so optimize this function call
if s.ambient_dimension == 2:
(x1, y1), (x2, y2) = s.args, o.args
rv = (x1*y2 - x2*y1).equals(0)
if rv is None:
raise Undecidable(filldedent(
'''Cannot determine if %s is a scalar multiple of
%s''' % (s, o)))
# if the vectors p1 and p2 are linearly dependent, then they must
# be scalar multiples of each other
m = Matrix([s.args, o.args])
return m.rank() < 2
@property
def is_zero(self):
"""True if every coordinate is zero, False if any coordinate is not zero,
and None if it cannot be determined."""
nonzero = [x.is_nonzero for x in self.args]
if any(nonzero):
return False
if any(x is None for x in nonzero):
return None
return True
@property
def length(self):
"""
Treating a Point as a Line, this returns 0 for the length of a Point.
Examples
========
>>> from sympy import Point
>>> p = Point(0, 1)
>>> p.length
0
"""
return S.Zero
def midpoint(self, p):
"""The midpoint between self and point p.
Parameters
==========
p : Point
Returns
=======
midpoint : Point
See Also
========
sympy.geometry.line.Segment.midpoint
Examples
========
>>> from sympy import Point
>>> p1, p2 = Point(1, 1), Point(13, 5)
>>> p1.midpoint(p2)
Point2D(7, 3)
"""
s, p = Point._normalize_dimension(self, Point(p))
return Point([simplify((a + b)*S.Half) for a, b in zip(s, p)])
@property
def origin(self):
"""A point of all zeros of the same ambient dimension
as the current point"""
return Point([0]*len(self), evaluate=False)
@property
def orthogonal_direction(self):
"""Returns a non-zero point that is orthogonal to the
line containing `self` and the origin.
Examples
========
>>> from sympy import Line, Point
>>> a = Point(1, 2, 3)
>>> a.orthogonal_direction
Point3D(-2, 1, 0)
>>> b = _
>>> Line(b, b.origin).is_perpendicular(Line(a, a.origin))
True
"""
dim = self.ambient_dimension
# if a coordinate is zero, we can put a 1 there and zeros elsewhere
if self[0].is_zero:
return Point([1] + (dim - 1)*[0])
if self[1].is_zero:
return Point([0,1] + (dim - 2)*[0])
# if the first two coordinates aren't zero, we can create a non-zero
# orthogonal vector by swapping them, negating one, and padding with zeros
return Point([-self[1], self[0]] + (dim - 2)*[0])
@staticmethod
def project(a, b):
"""Project the point `a` onto the line between the origin
and point `b` along the normal direction.
Parameters
==========
a : Point
b : Point
Returns
=======
p : Point
See Also
========
sympy.geometry.line.LinearEntity.projection
Examples
========
>>> from sympy import Line, Point
>>> a = Point(1, 2)
>>> b = Point(2, 5)
>>> z = a.origin
>>> p = Point.project(a, b)
>>> Line(p, a).is_perpendicular(Line(p, b))
True
>>> Point.is_collinear(z, p, b)
True
"""
a, b = Point._normalize_dimension(Point(a), Point(b))
if b.is_zero:
raise ValueError("Cannot project to the zero vector.")
return b*(a.dot(b) / b.dot(b))
def taxicab_distance(self, p):
"""The Taxicab Distance from self to point p.
Returns the sum of the horizontal and vertical distances to point p.
Parameters
==========
p : Point
Returns
=======
taxicab_distance : The sum of the horizontal
and vertical distances to point p.
See Also
========
sympy.geometry.point.Point.distance
Examples
========
>>> from sympy import Point
>>> p1, p2 = Point(1, 1), Point(4, 5)
>>> p1.taxicab_distance(p2)
7
"""
s, p = Point._normalize_dimension(self, Point(p))
return Add(*(abs(a - b) for a, b in zip(s, p)))
def canberra_distance(self, p):
"""The Canberra Distance from self to point p.
Returns the weighted sum of horizontal and vertical distances to
point p.
Parameters
==========
p : Point
Returns
=======
canberra_distance : The weighted sum of horizontal and vertical
distances to point p. The weight used is the sum of absolute values
of the coordinates.
Examples
========
>>> from sympy import Point
>>> p1, p2 = Point(1, 1), Point(3, 3)
>>> p1.canberra_distance(p2)
1
>>> p1, p2 = Point(0, 0), Point(3, 3)
>>> p1.canberra_distance(p2)
2
Raises
======
ValueError when both vectors are zero.
See Also
========
sympy.geometry.point.Point.distance
"""
s, p = Point._normalize_dimension(self, Point(p))
if self.is_zero and p.is_zero:
raise ValueError("Cannot project to the zero vector.")
return Add(*((abs(a - b)/(abs(a) + abs(b))) for a, b in zip(s, p)))
@property
def unit(self):
"""Return the Point that is in the same direction as `self`
and a distance of 1 from the origin"""
return self / abs(self)
class Point2D(Point):
"""A point in a 2-dimensional Euclidean space.
Parameters
==========
coords
A sequence of 2 coordinate values.
Attributes
==========
x
y
length
Raises
======
TypeError
When trying to add or subtract points with different dimensions.
When trying to create a point with more than two dimensions.
When `intersection` is called with object other than a Point.
See Also
========
sympy.geometry.line.Segment : Connects two Points
Examples
========
>>> from sympy import Point2D
>>> from sympy.abc import x
>>> Point2D(1, 2)
Point2D(1, 2)
>>> Point2D([1, 2])
Point2D(1, 2)
>>> Point2D(0, x)
Point2D(0, x)
Floats are automatically converted to Rational unless the
evaluate flag is False:
>>> Point2D(0.5, 0.25)
Point2D(1/2, 1/4)
>>> Point2D(0.5, 0.25, evaluate=False)
Point2D(0.5, 0.25)
"""
_ambient_dimension = 2
def __new__(cls, *args, _nocheck=False, **kwargs):
if not _nocheck:
kwargs['dim'] = 2
args = Point(*args, **kwargs)
return GeometryEntity.__new__(cls, *args)
def __contains__(self, item):
return item == self
@property
def bounds(self):
"""Return a tuple (xmin, ymin, xmax, ymax) representing the bounding
rectangle for the geometric figure.
"""
return (self.x, self.y, self.x, self.y)
def rotate(self, angle, pt=None):
"""Rotate ``angle`` radians counterclockwise about Point ``pt``.
See Also
========
translate, scale
Examples
========
>>> from sympy import Point2D, pi
>>> t = Point2D(1, 0)
>>> t.rotate(pi/2)
Point2D(0, 1)
>>> t.rotate(pi/2, (2, 0))
Point2D(2, -1)
"""
c = cos(angle)
s = sin(angle)
rv = self
if pt is not None:
pt = Point(pt, dim=2)
rv -= pt
x, y = rv.args
rv = Point(c*x - s*y, s*x + c*y)
if pt is not None:
rv += pt
return rv
def scale(self, x=1, y=1, pt=None):
"""Scale the coordinates of the Point by multiplying by
``x`` and ``y`` after subtracting ``pt`` -- default is (0, 0) --
and then adding ``pt`` back again (i.e. ``pt`` is the point of
reference for the scaling).
See Also
========
rotate, translate
Examples
========
>>> from sympy import Point2D
>>> t = Point2D(1, 1)
>>> t.scale(2)
Point2D(2, 1)
>>> t.scale(2, 2)
Point2D(2, 2)
"""
if pt:
pt = Point(pt, dim=2)
return self.translate(*(-pt).args).scale(x, y).translate(*pt.args)
return Point(self.x*x, self.y*y)
def transform(self, matrix):
"""Return the point after applying the transformation described
by the 3x3 Matrix, ``matrix``.
See Also
========
sympy.geometry.point.Point2D.rotate
sympy.geometry.point.Point2D.scale
sympy.geometry.point.Point2D.translate
"""
if not (matrix.is_Matrix and matrix.shape == (3, 3)):
raise ValueError("matrix must be a 3x3 matrix")
x, y = self.args
return Point(*(Matrix(1, 3, [x, y, 1])*matrix).tolist()[0][:2])
def translate(self, x=0, y=0):
"""Shift the Point by adding x and y to the coordinates of the Point.
See Also
========
sympy.geometry.point.Point2D.rotate, scale
Examples
========
>>> from sympy import Point2D
>>> t = Point2D(0, 1)
>>> t.translate(2)
Point2D(2, 1)
>>> t.translate(2, 2)
Point2D(2, 3)
>>> t + Point2D(2, 2)
Point2D(2, 3)
"""
return Point(self.x + x, self.y + y)
@property
def coordinates(self):
"""
Returns the two coordinates of the Point.
Examples
========
>>> from sympy import Point2D
>>> p = Point2D(0, 1)
>>> p.coordinates
(0, 1)
"""
return self.args
@property
def x(self):
"""
Returns the X coordinate of the Point.
Examples
========
>>> from sympy import Point2D
>>> p = Point2D(0, 1)
>>> p.x
0
"""
return self.args[0]
@property
def y(self):
"""
Returns the Y coordinate of the Point.
Examples
========
>>> from sympy import Point2D
>>> p = Point2D(0, 1)
>>> p.y
1
"""
return self.args[1]
class Point3D(Point):
"""A point in a 3-dimensional Euclidean space.
Parameters
==========
coords
A sequence of 3 coordinate values.
Attributes
==========
x
y
z
length
Raises
======
TypeError
When trying to add or subtract points with different dimensions.
When `intersection` is called with object other than a Point.
Examples
========
>>> from sympy import Point3D
>>> from sympy.abc import x
>>> Point3D(1, 2, 3)
Point3D(1, 2, 3)
>>> Point3D([1, 2, 3])
Point3D(1, 2, 3)
>>> Point3D(0, x, 3)
Point3D(0, x, 3)
Floats are automatically converted to Rational unless the
evaluate flag is False:
>>> Point3D(0.5, 0.25, 2)
Point3D(1/2, 1/4, 2)
>>> Point3D(0.5, 0.25, 3, evaluate=False)
Point3D(0.5, 0.25, 3)
"""
_ambient_dimension = 3
def __new__(cls, *args, _nocheck=False, **kwargs):
if not _nocheck:
kwargs['dim'] = 3
args = Point(*args, **kwargs)
return GeometryEntity.__new__(cls, *args)
def __contains__(self, item):
return item == self
@staticmethod
def are_collinear(*points):
"""Is a sequence of points collinear?
Test whether or not a set of points are collinear. Returns True if
the set of points are collinear, or False otherwise.
Parameters
==========
points : sequence of Point
Returns
=======
are_collinear : boolean
See Also
========
sympy.geometry.line.Line3D
Examples
========
>>> from sympy import Point3D
>>> from sympy.abc import x
>>> p1, p2 = Point3D(0, 0, 0), Point3D(1, 1, 1)
>>> p3, p4, p5 = Point3D(2, 2, 2), Point3D(x, x, x), Point3D(1, 2, 6)
>>> Point3D.are_collinear(p1, p2, p3, p4)
True
>>> Point3D.are_collinear(p1, p2, p3, p5)
False
"""
return Point.is_collinear(*points)
def direction_cosine(self, point):
"""
Gives the direction cosine between 2 points
Parameters
==========
p : Point3D
Returns
=======
list
Examples
========
>>> from sympy import Point3D
>>> p1 = Point3D(1, 2, 3)
>>> p1.direction_cosine(Point3D(2, 3, 5))
[sqrt(6)/6, sqrt(6)/6, sqrt(6)/3]
"""
a = self.direction_ratio(point)
b = sqrt(Add(*(i**2 for i in a)))
return [(point.x - self.x) / b,(point.y - self.y) / b,
(point.z - self.z) / b]
def direction_ratio(self, point):
"""
Gives the direction ratio between 2 points
Parameters
==========
p : Point3D
Returns
=======
list
Examples
========
>>> from sympy import Point3D
>>> p1 = Point3D(1, 2, 3)
>>> p1.direction_ratio(Point3D(2, 3, 5))
[1, 1, 2]
"""
return [(point.x - self.x),(point.y - self.y),(point.z - self.z)]
def intersection(self, other):
"""The intersection between this point and another GeometryEntity.
Parameters
==========
other : GeometryEntity or sequence of coordinates
Returns
=======
intersection : list of Points
Notes
=====
The return value will either be an empty list if there is no
intersection, otherwise it will contain this point.
Examples
========
>>> from sympy import Point3D
>>> p1, p2, p3 = Point3D(0, 0, 0), Point3D(1, 1, 1), Point3D(0, 0, 0)
>>> p1.intersection(p2)
[]
>>> p1.intersection(p3)
[Point3D(0, 0, 0)]
"""
if not isinstance(other, GeometryEntity):
other = Point(other, dim=3)
if isinstance(other, Point3D):
if self == other:
return [self]
return []
return other.intersection(self)
def scale(self, x=1, y=1, z=1, pt=None):
"""Scale the coordinates of the Point by multiplying by
``x`` and ``y`` after subtracting ``pt`` -- default is (0, 0) --
and then adding ``pt`` back again (i.e. ``pt`` is the point of
reference for the scaling).
See Also
========
translate
Examples
========
>>> from sympy import Point3D
>>> t = Point3D(1, 1, 1)
>>> t.scale(2)
Point3D(2, 1, 1)
>>> t.scale(2, 2)
Point3D(2, 2, 1)
"""
if pt:
pt = Point3D(pt)
return self.translate(*(-pt).args).scale(x, y, z).translate(*pt.args)
return Point3D(self.x*x, self.y*y, self.z*z)
def transform(self, matrix):
"""Return the point after applying the transformation described
by the 4x4 Matrix, ``matrix``.
See Also
========
sympy.geometry.point.Point3D.scale
sympy.geometry.point.Point3D.translate
"""
if not (matrix.is_Matrix and matrix.shape == (4, 4)):
raise ValueError("matrix must be a 4x4 matrix")
x, y, z = self.args
m = Transpose(matrix)
return Point3D(*(Matrix(1, 4, [x, y, z, 1])*m).tolist()[0][:3])
def translate(self, x=0, y=0, z=0):
"""Shift the Point by adding x and y to the coordinates of the Point.
See Also
========
scale
Examples
========
>>> from sympy import Point3D
>>> t = Point3D(0, 1, 1)
>>> t.translate(2)
Point3D(2, 1, 1)
>>> t.translate(2, 2)
Point3D(2, 3, 1)
>>> t + Point3D(2, 2, 2)
Point3D(2, 3, 3)
"""
return Point3D(self.x + x, self.y + y, self.z + z)
@property
def coordinates(self):
"""
Returns the three coordinates of the Point.
Examples
========
>>> from sympy import Point3D
>>> p = Point3D(0, 1, 2)
>>> p.coordinates
(0, 1, 2)
"""
return self.args
@property
def x(self):
"""
Returns the X coordinate of the Point.
Examples
========
>>> from sympy import Point3D
>>> p = Point3D(0, 1, 3)
>>> p.x
0
"""
return self.args[0]
@property
def y(self):
"""
Returns the Y coordinate of the Point.
Examples
========
>>> from sympy import Point3D
>>> p = Point3D(0, 1, 2)
>>> p.y
1
"""
return self.args[1]
@property
def z(self):
"""
Returns the Z coordinate of the Point.
Examples
========
>>> from sympy import Point3D
>>> p = Point3D(0, 1, 1)
>>> p.z
1
"""
return self.args[2]
PK ]ZZZ�sk@ k@ sympy/geometry/polygon.pyfrom sympy.core import Expr, S, oo, pi, sympify
from sympy.core.evalf import N
from sympy.core.sorting import default_sort_key, ordered
from sympy.core.symbol import _symbol, Dummy, Symbol
from sympy.functions.elementary.complexes import sign
from sympy.functions.elementary.piecewise import Piecewise
from sympy.functions.elementary.trigonometric import cos, sin, tan
from .ellipse import Circle
from .entity import GeometryEntity, GeometrySet
from .exceptions import GeometryError
from .line import Line, Segment, Ray
from .point import Point
from sympy.logic import And
from sympy.matrices import Matrix
from sympy.simplify.simplify import simplify
from sympy.solvers.solvers import solve
from sympy.utilities.iterables import has_dups, has_variety, uniq, rotate_left, least_rotation
from sympy.utilities.misc import as_int, func_name
from mpmath.libmp.libmpf import prec_to_dps
import warnings
x, y, T = [Dummy('polygon_dummy', real=True) for i in range(3)]
class Polygon(GeometrySet):
"""A two-dimensional polygon.
A simple polygon in space. Can be constructed from a sequence of points
or from a center, radius, number of sides and rotation angle.
Parameters
==========
vertices
A sequence of points.
n : int, optional
If $> 0$, an n-sided RegularPolygon is created.
Default value is $0$.
Attributes
==========
area
angles
perimeter
vertices
centroid
sides
Raises
======
GeometryError
If all parameters are not Points.
See Also
========
sympy.geometry.point.Point, sympy.geometry.line.Segment, Triangle
Notes
=====
Polygons are treated as closed paths rather than 2D areas so
some calculations can be be negative or positive (e.g., area)
based on the orientation of the points.
Any consecutive identical points are reduced to a single point
and any points collinear and between two points will be removed
unless they are needed to define an explicit intersection (see examples).
A Triangle, Segment or Point will be returned when there are 3 or
fewer points provided.
Examples
========
>>> from sympy import Polygon, pi
>>> p1, p2, p3, p4, p5 = [(0, 0), (1, 0), (5, 1), (0, 1), (3, 0)]
>>> Polygon(p1, p2, p3, p4)
Polygon(Point2D(0, 0), Point2D(1, 0), Point2D(5, 1), Point2D(0, 1))
>>> Polygon(p1, p2)
Segment2D(Point2D(0, 0), Point2D(1, 0))
>>> Polygon(p1, p2, p5)
Segment2D(Point2D(0, 0), Point2D(3, 0))
The area of a polygon is calculated as positive when vertices are
traversed in a ccw direction. When the sides of a polygon cross the
area will have positive and negative contributions. The following
defines a Z shape where the bottom right connects back to the top
left.
>>> Polygon((0, 2), (2, 2), (0, 0), (2, 0)).area
0
When the keyword `n` is used to define the number of sides of the
Polygon then a RegularPolygon is created and the other arguments are
interpreted as center, radius and rotation. The unrotated RegularPolygon
will always have a vertex at Point(r, 0) where `r` is the radius of the
circle that circumscribes the RegularPolygon. Its method `spin` can be
used to increment that angle.
>>> p = Polygon((0,0), 1, n=3)
>>> p
RegularPolygon(Point2D(0, 0), 1, 3, 0)
>>> p.vertices[0]
Point2D(1, 0)
>>> p.args[0]
Point2D(0, 0)
>>> p.spin(pi/2)
>>> p.vertices[0]
Point2D(0, 1)
"""
__slots__ = ()
def __new__(cls, *args, n = 0, **kwargs):
if n:
args = list(args)
# return a virtual polygon with n sides
if len(args) == 2: # center, radius
args.append(n)
elif len(args) == 3: # center, radius, rotation
args.insert(2, n)
return RegularPolygon(*args, **kwargs)
vertices = [Point(a, dim=2, **kwargs) for a in args]
# remove consecutive duplicates
nodup = []
for p in vertices:
if nodup and p == nodup[-1]:
continue
nodup.append(p)
if len(nodup) > 1 and nodup[-1] == nodup[0]:
nodup.pop() # last point was same as first
# remove collinear points
i = -3
while i < len(nodup) - 3 and len(nodup) > 2:
a, b, c = nodup[i], nodup[i + 1], nodup[i + 2]
if Point.is_collinear(a, b, c):
nodup.pop(i + 1)
if a == c:
nodup.pop(i)
else:
i += 1
vertices = list(nodup)
if len(vertices) > 3:
return GeometryEntity.__new__(cls, *vertices, **kwargs)
elif len(vertices) == 3:
return Triangle(*vertices, **kwargs)
elif len(vertices) == 2:
return Segment(*vertices, **kwargs)
else:
return Point(*vertices, **kwargs)
@property
def area(self):
"""
The area of the polygon.
Notes
=====
The area calculation can be positive or negative based on the
orientation of the points. If any side of the polygon crosses
any other side, there will be areas having opposite signs.
See Also
========
sympy.geometry.ellipse.Ellipse.area
Examples
========
>>> from sympy import Point, Polygon
>>> p1, p2, p3, p4 = map(Point, [(0, 0), (1, 0), (5, 1), (0, 1)])
>>> poly = Polygon(p1, p2, p3, p4)
>>> poly.area
3
In the Z shaped polygon (with the lower right connecting back
to the upper left) the areas cancel out:
>>> Z = Polygon((0, 1), (1, 1), (0, 0), (1, 0))
>>> Z.area
0
In the M shaped polygon, areas do not cancel because no side
crosses any other (though there is a point of contact).
>>> M = Polygon((0, 0), (0, 1), (2, 0), (3, 1), (3, 0))
>>> M.area
-3/2
"""
area = 0
args = self.args
for i in range(len(args)):
x1, y1 = args[i - 1].args
x2, y2 = args[i].args
area += x1*y2 - x2*y1
return simplify(area) / 2
@staticmethod
def _is_clockwise(a, b, c):
"""Return True/False for cw/ccw orientation.
Examples
========
>>> from sympy import Point, Polygon
>>> a, b, c = [Point(i) for i in [(0, 0), (1, 1), (1, 0)]]
>>> Polygon._is_clockwise(a, b, c)
True
>>> Polygon._is_clockwise(a, c, b)
False
"""
ba = b - a
ca = c - a
t_area = simplify(ba.x*ca.y - ca.x*ba.y)
res = t_area.is_nonpositive
if res is None:
raise ValueError("Can't determine orientation")
return res
@property
def angles(self):
"""The internal angle at each vertex.
Returns
=======
angles : dict
A dictionary where each key is a vertex and each value is the
internal angle at that vertex. The vertices are represented as
Points.
See Also
========
sympy.geometry.point.Point, sympy.geometry.line.LinearEntity.angle_between
Examples
========
>>> from sympy import Point, Polygon
>>> p1, p2, p3, p4 = map(Point, [(0, 0), (1, 0), (5, 1), (0, 1)])
>>> poly = Polygon(p1, p2, p3, p4)
>>> poly.angles[p1]
pi/2
>>> poly.angles[p2]
acos(-4*sqrt(17)/17)
"""
args = self.vertices
n = len(args)
ret = {}
for i in range(n):
a, b, c = args[i - 2], args[i - 1], args[i]
reflex_ang = Ray(b, a).angle_between(Ray(b, c))
if self._is_clockwise(a, b, c):
ret[b] = 2*S.Pi - reflex_ang
else:
ret[b] = reflex_ang
# internal sum should be pi*(n - 2), not pi*(n+2)
# so if ratio is (n+2)/(n-2) > 1 it is wrong
wrong = ((sum(ret.values())/S.Pi-1)/(n - 2) - 1).is_positive
if wrong:
two_pi = 2*S.Pi
for b in ret:
ret[b] = two_pi - ret[b]
elif wrong is None:
raise ValueError("could not determine Polygon orientation.")
return ret
@property
def ambient_dimension(self):
return self.vertices[0].ambient_dimension
@property
def perimeter(self):
"""The perimeter of the polygon.
Returns
=======
perimeter : number or Basic instance
See Also
========
sympy.geometry.line.Segment.length
Examples
========
>>> from sympy import Point, Polygon
>>> p1, p2, p3, p4 = map(Point, [(0, 0), (1, 0), (5, 1), (0, 1)])
>>> poly = Polygon(p1, p2, p3, p4)
>>> poly.perimeter
sqrt(17) + 7
"""
p = 0
args = self.vertices
for i in range(len(args)):
p += args[i - 1].distance(args[i])
return simplify(p)
@property
def vertices(self):
"""The vertices of the polygon.
Returns
=======
vertices : list of Points
Notes
=====
When iterating over the vertices, it is more efficient to index self
rather than to request the vertices and index them. Only use the
vertices when you want to process all of them at once. This is even
more important with RegularPolygons that calculate each vertex.
See Also
========
sympy.geometry.point.Point
Examples
========
>>> from sympy import Point, Polygon
>>> p1, p2, p3, p4 = map(Point, [(0, 0), (1, 0), (5, 1), (0, 1)])
>>> poly = Polygon(p1, p2, p3, p4)
>>> poly.vertices
[Point2D(0, 0), Point2D(1, 0), Point2D(5, 1), Point2D(0, 1)]
>>> poly.vertices[0]
Point2D(0, 0)
"""
return list(self.args)
@property
def centroid(self):
"""The centroid of the polygon.
Returns
=======
centroid : Point
See Also
========
sympy.geometry.point.Point, sympy.geometry.util.centroid
Examples
========
>>> from sympy import Point, Polygon
>>> p1, p2, p3, p4 = map(Point, [(0, 0), (1, 0), (5, 1), (0, 1)])
>>> poly = Polygon(p1, p2, p3, p4)
>>> poly.centroid
Point2D(31/18, 11/18)
"""
A = 1/(6*self.area)
cx, cy = 0, 0
args = self.args
for i in range(len(args)):
x1, y1 = args[i - 1].args
x2, y2 = args[i].args
v = x1*y2 - x2*y1
cx += v*(x1 + x2)
cy += v*(y1 + y2)
return Point(simplify(A*cx), simplify(A*cy))
def second_moment_of_area(self, point=None):
"""Returns the second moment and product moment of area of a two dimensional polygon.
Parameters
==========
point : Point, two-tuple of sympifyable objects, or None(default=None)
point is the point about which second moment of area is to be found.
If "point=None" it will be calculated about the axis passing through the
centroid of the polygon.
Returns
=======
I_xx, I_yy, I_xy : number or SymPy expression
I_xx, I_yy are second moment of area of a two dimensional polygon.
I_xy is product moment of area of a two dimensional polygon.
Examples
========
>>> from sympy import Polygon, symbols
>>> a, b = symbols('a, b')
>>> p1, p2, p3, p4, p5 = [(0, 0), (a, 0), (a, b), (0, b), (a/3, b/3)]
>>> rectangle = Polygon(p1, p2, p3, p4)
>>> rectangle.second_moment_of_area()
(a*b**3/12, a**3*b/12, 0)
>>> rectangle.second_moment_of_area(p5)
(a*b**3/9, a**3*b/9, a**2*b**2/36)
References
==========
.. [1] https://en.wikipedia.org/wiki/Second_moment_of_area
"""
I_xx, I_yy, I_xy = 0, 0, 0
args = self.vertices
for i in range(len(args)):
x1, y1 = args[i-1].args
x2, y2 = args[i].args
v = x1*y2 - x2*y1
I_xx += (y1**2 + y1*y2 + y2**2)*v
I_yy += (x1**2 + x1*x2 + x2**2)*v
I_xy += (x1*y2 + 2*x1*y1 + 2*x2*y2 + x2*y1)*v
A = self.area
c_x = self.centroid[0]
c_y = self.centroid[1]
# parallel axis theorem
I_xx_c = (I_xx/12) - (A*(c_y**2))
I_yy_c = (I_yy/12) - (A*(c_x**2))
I_xy_c = (I_xy/24) - (A*(c_x*c_y))
if point is None:
return I_xx_c, I_yy_c, I_xy_c
I_xx = (I_xx_c + A*((point[1]-c_y)**2))
I_yy = (I_yy_c + A*((point[0]-c_x)**2))
I_xy = (I_xy_c + A*((point[0]-c_x)*(point[1]-c_y)))
return I_xx, I_yy, I_xy
def first_moment_of_area(self, point=None):
"""
Returns the first moment of area of a two-dimensional polygon with
respect to a certain point of interest.
First moment of area is a measure of the distribution of the area
of a polygon in relation to an axis. The first moment of area of
the entire polygon about its own centroid is always zero. Therefore,
here it is calculated for an area, above or below a certain point
of interest, that makes up a smaller portion of the polygon. This
area is bounded by the point of interest and the extreme end
(top or bottom) of the polygon. The first moment for this area is
is then determined about the centroidal axis of the initial polygon.
References
==========
.. [1] https://skyciv.com/docs/tutorials/section-tutorials/calculating-the-statical-or-first-moment-of-area-of-beam-sections/?cc=BMD
.. [2] https://mechanicalc.com/reference/cross-sections
Parameters
==========
point: Point, two-tuple of sympifyable objects, or None (default=None)
point is the point above or below which the area of interest lies
If ``point=None`` then the centroid acts as the point of interest.
Returns
=======
Q_x, Q_y: number or SymPy expressions
Q_x is the first moment of area about the x-axis
Q_y is the first moment of area about the y-axis
A negative sign indicates that the section modulus is
determined for a section below (or left of) the centroidal axis
Examples
========
>>> from sympy import Point, Polygon
>>> a, b = 50, 10
>>> p1, p2, p3, p4 = [(0, b), (0, 0), (a, 0), (a, b)]
>>> p = Polygon(p1, p2, p3, p4)
>>> p.first_moment_of_area()
(625, 3125)
>>> p.first_moment_of_area(point=Point(30, 7))
(525, 3000)
"""
if point:
xc, yc = self.centroid
else:
point = self.centroid
xc, yc = point
h_line = Line(point, slope=0)
v_line = Line(point, slope=S.Infinity)
h_poly = self.cut_section(h_line)
v_poly = self.cut_section(v_line)
poly_1 = h_poly[0] if h_poly[0].area <= h_poly[1].area else h_poly[1]
poly_2 = v_poly[0] if v_poly[0].area <= v_poly[1].area else v_poly[1]
Q_x = (poly_1.centroid.y - yc)*poly_1.area
Q_y = (poly_2.centroid.x - xc)*poly_2.area
return Q_x, Q_y
def polar_second_moment_of_area(self):
"""Returns the polar modulus of a two-dimensional polygon
It is a constituent of the second moment of area, linked through
the perpendicular axis theorem. While the planar second moment of
area describes an object's resistance to deflection (bending) when
subjected to a force applied to a plane parallel to the central
axis, the polar second moment of area describes an object's
resistance to deflection when subjected to a moment applied in a
plane perpendicular to the object's central axis (i.e. parallel to
the cross-section)
Examples
========
>>> from sympy import Polygon, symbols
>>> a, b = symbols('a, b')
>>> rectangle = Polygon((0, 0), (a, 0), (a, b), (0, b))
>>> rectangle.polar_second_moment_of_area()
a**3*b/12 + a*b**3/12
References
==========
.. [1] https://en.wikipedia.org/wiki/Polar_moment_of_inertia
"""
second_moment = self.second_moment_of_area()
return second_moment[0] + second_moment[1]
def section_modulus(self, point=None):
"""Returns a tuple with the section modulus of a two-dimensional
polygon.
Section modulus is a geometric property of a polygon defined as the
ratio of second moment of area to the distance of the extreme end of
the polygon from the centroidal axis.
Parameters
==========
point : Point, two-tuple of sympifyable objects, or None(default=None)
point is the point at which section modulus is to be found.
If "point=None" it will be calculated for the point farthest from the
centroidal axis of the polygon.
Returns
=======
S_x, S_y: numbers or SymPy expressions
S_x is the section modulus with respect to the x-axis
S_y is the section modulus with respect to the y-axis
A negative sign indicates that the section modulus is
determined for a point below the centroidal axis
Examples
========
>>> from sympy import symbols, Polygon, Point
>>> a, b = symbols('a, b', positive=True)
>>> rectangle = Polygon((0, 0), (a, 0), (a, b), (0, b))
>>> rectangle.section_modulus()
(a*b**2/6, a**2*b/6)
>>> rectangle.section_modulus(Point(a/4, b/4))
(-a*b**2/3, -a**2*b/3)
References
==========
.. [1] https://en.wikipedia.org/wiki/Section_modulus
"""
x_c, y_c = self.centroid
if point is None:
# taking x and y as maximum distances from centroid
x_min, y_min, x_max, y_max = self.bounds
y = max(y_c - y_min, y_max - y_c)
x = max(x_c - x_min, x_max - x_c)
else:
# taking x and y as distances of the given point from the centroid
y = point.y - y_c
x = point.x - x_c
second_moment= self.second_moment_of_area()
S_x = second_moment[0]/y
S_y = second_moment[1]/x
return S_x, S_y
@property
def sides(self):
"""The directed line segments that form the sides of the polygon.
Returns
=======
sides : list of sides
Each side is a directed Segment.
See Also
========
sympy.geometry.point.Point, sympy.geometry.line.Segment
Examples
========
>>> from sympy import Point, Polygon
>>> p1, p2, p3, p4 = map(Point, [(0, 0), (1, 0), (5, 1), (0, 1)])
>>> poly = Polygon(p1, p2, p3, p4)
>>> poly.sides
[Segment2D(Point2D(0, 0), Point2D(1, 0)),
Segment2D(Point2D(1, 0), Point2D(5, 1)),
Segment2D(Point2D(5, 1), Point2D(0, 1)), Segment2D(Point2D(0, 1), Point2D(0, 0))]
"""
res = []
args = self.vertices
for i in range(-len(args), 0):
res.append(Segment(args[i], args[i + 1]))
return res
@property
def bounds(self):
"""Return a tuple (xmin, ymin, xmax, ymax) representing the bounding
rectangle for the geometric figure.
"""
verts = self.vertices
xs = [p.x for p in verts]
ys = [p.y for p in verts]
return (min(xs), min(ys), max(xs), max(ys))
def is_convex(self):
"""Is the polygon convex?
A polygon is convex if all its interior angles are less than 180
degrees and there are no intersections between sides.
Returns
=======
is_convex : boolean
True if this polygon is convex, False otherwise.
See Also
========
sympy.geometry.util.convex_hull
Examples
========
>>> from sympy import Point, Polygon
>>> p1, p2, p3, p4 = map(Point, [(0, 0), (1, 0), (5, 1), (0, 1)])
>>> poly = Polygon(p1, p2, p3, p4)
>>> poly.is_convex()
True
"""
# Determine orientation of points
args = self.vertices
cw = self._is_clockwise(args[-2], args[-1], args[0])
for i in range(1, len(args)):
if cw ^ self._is_clockwise(args[i - 2], args[i - 1], args[i]):
return False
# check for intersecting sides
sides = self.sides
for i, si in enumerate(sides):
pts = si.args
# exclude the sides connected to si
for j in range(1 if i == len(sides) - 1 else 0, i - 1):
sj = sides[j]
if sj.p1 not in pts and sj.p2 not in pts:
hit = si.intersection(sj)
if hit:
return False
return True
def encloses_point(self, p):
"""
Return True if p is enclosed by (is inside of) self.
Notes
=====
Being on the border of self is considered False.
Parameters
==========
p : Point
Returns
=======
encloses_point : True, False or None
See Also
========
sympy.geometry.point.Point, sympy.geometry.ellipse.Ellipse.encloses_point
Examples
========
>>> from sympy import Polygon, Point
>>> p = Polygon((0, 0), (4, 0), (4, 4))
>>> p.encloses_point(Point(2, 1))
True
>>> p.encloses_point(Point(2, 2))
False
>>> p.encloses_point(Point(5, 5))
False
References
==========
.. [1] https://paulbourke.net/geometry/polygonmesh/#insidepoly
"""
p = Point(p, dim=2)
if p in self.vertices or any(p in s for s in self.sides):
return False
# move to p, checking that the result is numeric
lit = []
for v in self.vertices:
lit.append(v - p) # the difference is simplified
if lit[-1].free_symbols:
return None
poly = Polygon(*lit)
# polygon closure is assumed in the following test but Polygon removes duplicate pts so
# the last point has to be added so all sides are computed. Using Polygon.sides is
# not good since Segments are unordered.
args = poly.args
indices = list(range(-len(args), 1))
if poly.is_convex():
orientation = None
for i in indices:
a = args[i]
b = args[i + 1]
test = ((-a.y)*(b.x - a.x) - (-a.x)*(b.y - a.y)).is_negative
if orientation is None:
orientation = test
elif test is not orientation:
return False
return True
hit_odd = False
p1x, p1y = args[0].args
for i in indices[1:]:
p2x, p2y = args[i].args
if 0 > min(p1y, p2y):
if 0 <= max(p1y, p2y):
if 0 <= max(p1x, p2x):
if p1y != p2y:
xinters = (-p1y)*(p2x - p1x)/(p2y - p1y) + p1x
if p1x == p2x or 0 <= xinters:
hit_odd = not hit_odd
p1x, p1y = p2x, p2y
return hit_odd
def arbitrary_point(self, parameter='t'):
"""A parameterized point on the polygon.
The parameter, varying from 0 to 1, assigns points to the position on
the perimeter that is that fraction of the total perimeter. So the
point evaluated at t=1/2 would return the point from the first vertex
that is 1/2 way around the polygon.
Parameters
==========
parameter : str, optional
Default value is 't'.
Returns
=======
arbitrary_point : Point
Raises
======
ValueError
When `parameter` already appears in the Polygon's definition.
See Also
========
sympy.geometry.point.Point
Examples
========
>>> from sympy import Polygon, Symbol
>>> t = Symbol('t', real=True)
>>> tri = Polygon((0, 0), (1, 0), (1, 1))
>>> p = tri.arbitrary_point('t')
>>> perimeter = tri.perimeter
>>> s1, s2 = [s.length for s in tri.sides[:2]]
>>> p.subs(t, (s1 + s2/2)/perimeter)
Point2D(1, 1/2)
"""
t = _symbol(parameter, real=True)
if t.name in (f.name for f in self.free_symbols):
raise ValueError('Symbol %s already appears in object and cannot be used as a parameter.' % t.name)
sides = []
perimeter = self.perimeter
perim_fraction_start = 0
for s in self.sides:
side_perim_fraction = s.length/perimeter
perim_fraction_end = perim_fraction_start + side_perim_fraction
pt = s.arbitrary_point(parameter).subs(
t, (t - perim_fraction_start)/side_perim_fraction)
sides.append(
(pt, (And(perim_fraction_start <= t, t < perim_fraction_end))))
perim_fraction_start = perim_fraction_end
return Piecewise(*sides)
def parameter_value(self, other, t):
if not isinstance(other,GeometryEntity):
other = Point(other, dim=self.ambient_dimension)
if not isinstance(other,Point):
raise ValueError("other must be a point")
if other.free_symbols:
raise NotImplementedError('non-numeric coordinates')
unknown = False
p = self.arbitrary_point(T)
for pt, cond in p.args:
sol = solve(pt - other, T, dict=True)
if not sol:
continue
value = sol[0][T]
if simplify(cond.subs(T, value)) == True:
return {t: value}
unknown = True
if unknown:
raise ValueError("Given point may not be on %s" % func_name(self))
raise ValueError("Given point is not on %s" % func_name(self))
def plot_interval(self, parameter='t'):
"""The plot interval for the default geometric plot of the polygon.
Parameters
==========
parameter : str, optional
Default value is 't'.
Returns
=======
plot_interval : list (plot interval)
[parameter, lower_bound, upper_bound]
Examples
========
>>> from sympy import Polygon
>>> p = Polygon((0, 0), (1, 0), (1, 1))
>>> p.plot_interval()
[t, 0, 1]
"""
t = Symbol(parameter, real=True)
return [t, 0, 1]
def intersection(self, o):
"""The intersection of polygon and geometry entity.
The intersection may be empty and can contain individual Points and
complete Line Segments.
Parameters
==========
other: GeometryEntity
Returns
=======
intersection : list
The list of Segments and Points
See Also
========
sympy.geometry.point.Point, sympy.geometry.line.Segment
Examples
========
>>> from sympy import Point, Polygon, Line
>>> p1, p2, p3, p4 = map(Point, [(0, 0), (1, 0), (5, 1), (0, 1)])
>>> poly1 = Polygon(p1, p2, p3, p4)
>>> p5, p6, p7 = map(Point, [(3, 2), (1, -1), (0, 2)])
>>> poly2 = Polygon(p5, p6, p7)
>>> poly1.intersection(poly2)
[Point2D(1/3, 1), Point2D(2/3, 0), Point2D(9/5, 1/5), Point2D(7/3, 1)]
>>> poly1.intersection(Line(p1, p2))
[Segment2D(Point2D(0, 0), Point2D(1, 0))]
>>> poly1.intersection(p1)
[Point2D(0, 0)]
"""
intersection_result = []
k = o.sides if isinstance(o, Polygon) else [o]
for side in self.sides:
for side1 in k:
intersection_result.extend(side.intersection(side1))
intersection_result = list(uniq(intersection_result))
points = [entity for entity in intersection_result if isinstance(entity, Point)]
segments = [entity for entity in intersection_result if isinstance(entity, Segment)]
if points and segments:
points_in_segments = list(uniq([point for point in points for segment in segments if point in segment]))
if points_in_segments:
for i in points_in_segments:
points.remove(i)
return list(ordered(segments + points))
else:
return list(ordered(intersection_result))
def cut_section(self, line):
"""
Returns a tuple of two polygon segments that lie above and below
the intersecting line respectively.
Parameters
==========
line: Line object of geometry module
line which cuts the Polygon. The part of the Polygon that lies
above and below this line is returned.
Returns
=======
upper_polygon, lower_polygon: Polygon objects or None
upper_polygon is the polygon that lies above the given line.
lower_polygon is the polygon that lies below the given line.
upper_polygon and lower polygon are ``None`` when no polygon
exists above the line or below the line.
Raises
======
ValueError: When the line does not intersect the polygon
Examples
========
>>> from sympy import Polygon, Line
>>> a, b = 20, 10
>>> p1, p2, p3, p4 = [(0, b), (0, 0), (a, 0), (a, b)]
>>> rectangle = Polygon(p1, p2, p3, p4)
>>> t = rectangle.cut_section(Line((0, 5), slope=0))
>>> t
(Polygon(Point2D(0, 10), Point2D(0, 5), Point2D(20, 5), Point2D(20, 10)),
Polygon(Point2D(0, 5), Point2D(0, 0), Point2D(20, 0), Point2D(20, 5)))
>>> upper_segment, lower_segment = t
>>> upper_segment.area
100
>>> upper_segment.centroid
Point2D(10, 15/2)
>>> lower_segment.centroid
Point2D(10, 5/2)
References
==========
.. [1] https://github.com/sympy/sympy/wiki/A-method-to-return-a-cut-section-of-any-polygon-geometry
"""
intersection_points = self.intersection(line)
if not intersection_points:
raise ValueError("This line does not intersect the polygon")
points = list(self.vertices)
points.append(points[0])
eq = line.equation(x, y)
# considering equation of line to be `ax +by + c`
a = eq.coeff(x)
b = eq.coeff(y)
upper_vertices = []
lower_vertices = []
# prev is true when previous point is above the line
prev = True
prev_point = None
for point in points:
# when coefficient of y is 0, right side of the line is
# considered
compare = eq.subs({x: point.x, y: point.y})/b if b \
else eq.subs(x, point.x)/a
# if point lies above line
if compare > 0:
if not prev:
# if previous point lies below the line, the intersection
# point of the polygon edge and the line has to be included
edge = Line(point, prev_point)
new_point = edge.intersection(line)
upper_vertices.append(new_point[0])
lower_vertices.append(new_point[0])
upper_vertices.append(point)
prev = True
else:
if prev and prev_point:
edge = Line(point, prev_point)
new_point = edge.intersection(line)
upper_vertices.append(new_point[0])
lower_vertices.append(new_point[0])
lower_vertices.append(point)
prev = False
prev_point = point
upper_polygon, lower_polygon = None, None
if upper_vertices and isinstance(Polygon(*upper_vertices), Polygon):
upper_polygon = Polygon(*upper_vertices)
if lower_vertices and isinstance(Polygon(*lower_vertices), Polygon):
lower_polygon = Polygon(*lower_vertices)
return upper_polygon, lower_polygon
def distance(self, o):
"""
Returns the shortest distance between self and o.
If o is a point, then self does not need to be convex.
If o is another polygon self and o must be convex.
Examples
========
>>> from sympy import Point, Polygon, RegularPolygon
>>> p1, p2 = map(Point, [(0, 0), (7, 5)])
>>> poly = Polygon(*RegularPolygon(p1, 1, 3).vertices)
>>> poly.distance(p2)
sqrt(61)
"""
if isinstance(o, Point):
dist = oo
for side in self.sides:
current = side.distance(o)
if current == 0:
return S.Zero
elif current < dist:
dist = current
return dist
elif isinstance(o, Polygon) and self.is_convex() and o.is_convex():
return self._do_poly_distance(o)
raise NotImplementedError()
def _do_poly_distance(self, e2):
"""
Calculates the least distance between the exteriors of two
convex polygons e1 and e2. Does not check for the convexity
of the polygons as this is checked by Polygon.distance.
Notes
=====
- Prints a warning if the two polygons possibly intersect as the return
value will not be valid in such a case. For a more through test of
intersection use intersection().
See Also
========
sympy.geometry.point.Point.distance
Examples
========
>>> from sympy import Point, Polygon
>>> square = Polygon(Point(0, 0), Point(0, 1), Point(1, 1), Point(1, 0))
>>> triangle = Polygon(Point(1, 2), Point(2, 2), Point(2, 1))
>>> square._do_poly_distance(triangle)
sqrt(2)/2
Description of method used
==========================
Method:
[1] https://web.archive.org/web/20150509035744/http://cgm.cs.mcgill.ca/~orm/mind2p.html
Uses rotating calipers:
[2] https://en.wikipedia.org/wiki/Rotating_calipers
and antipodal points:
[3] https://en.wikipedia.org/wiki/Antipodal_point
"""
e1 = self
'''Tests for a possible intersection between the polygons and outputs a warning'''
e1_center = e1.centroid
e2_center = e2.centroid
e1_max_radius = S.Zero
e2_max_radius = S.Zero
for vertex in e1.vertices:
r = Point.distance(e1_center, vertex)
if e1_max_radius < r:
e1_max_radius = r
for vertex in e2.vertices:
r = Point.distance(e2_center, vertex)
if e2_max_radius < r:
e2_max_radius = r
center_dist = Point.distance(e1_center, e2_center)
if center_dist <= e1_max_radius + e2_max_radius:
warnings.warn("Polygons may intersect producing erroneous output",
stacklevel=3)
'''
Find the upper rightmost vertex of e1 and the lowest leftmost vertex of e2
'''
e1_ymax = Point(0, -oo)
e2_ymin = Point(0, oo)
for vertex in e1.vertices:
if vertex.y > e1_ymax.y or (vertex.y == e1_ymax.y and vertex.x > e1_ymax.x):
e1_ymax = vertex
for vertex in e2.vertices:
if vertex.y < e2_ymin.y or (vertex.y == e2_ymin.y and vertex.x < e2_ymin.x):
e2_ymin = vertex
min_dist = Point.distance(e1_ymax, e2_ymin)
'''
Produce a dictionary with vertices of e1 as the keys and, for each vertex, the points
to which the vertex is connected as its value. The same is then done for e2.
'''
e1_connections = {}
e2_connections = {}
for side in e1.sides:
if side.p1 in e1_connections:
e1_connections[side.p1].append(side.p2)
else:
e1_connections[side.p1] = [side.p2]
if side.p2 in e1_connections:
e1_connections[side.p2].append(side.p1)
else:
e1_connections[side.p2] = [side.p1]
for side in e2.sides:
if side.p1 in e2_connections:
e2_connections[side.p1].append(side.p2)
else:
e2_connections[side.p1] = [side.p2]
if side.p2 in e2_connections:
e2_connections[side.p2].append(side.p1)
else:
e2_connections[side.p2] = [side.p1]
e1_current = e1_ymax
e2_current = e2_ymin
support_line = Line(Point(S.Zero, S.Zero), Point(S.One, S.Zero))
'''
Determine which point in e1 and e2 will be selected after e2_ymin and e1_ymax,
this information combined with the above produced dictionaries determines the
path that will be taken around the polygons
'''
point1 = e1_connections[e1_ymax][0]
point2 = e1_connections[e1_ymax][1]
angle1 = support_line.angle_between(Line(e1_ymax, point1))
angle2 = support_line.angle_between(Line(e1_ymax, point2))
if angle1 < angle2:
e1_next = point1
elif angle2 < angle1:
e1_next = point2
elif Point.distance(e1_ymax, point1) > Point.distance(e1_ymax, point2):
e1_next = point2
else:
e1_next = point1
point1 = e2_connections[e2_ymin][0]
point2 = e2_connections[e2_ymin][1]
angle1 = support_line.angle_between(Line(e2_ymin, point1))
angle2 = support_line.angle_between(Line(e2_ymin, point2))
if angle1 > angle2:
e2_next = point1
elif angle2 > angle1:
e2_next = point2
elif Point.distance(e2_ymin, point1) > Point.distance(e2_ymin, point2):
e2_next = point2
else:
e2_next = point1
'''
Loop which determines the distance between anti-podal pairs and updates the
minimum distance accordingly. It repeats until it reaches the starting position.
'''
while True:
e1_angle = support_line.angle_between(Line(e1_current, e1_next))
e2_angle = pi - support_line.angle_between(Line(
e2_current, e2_next))
if (e1_angle < e2_angle) is True:
support_line = Line(e1_current, e1_next)
e1_segment = Segment(e1_current, e1_next)
min_dist_current = e1_segment.distance(e2_current)
if min_dist_current.evalf() < min_dist.evalf():
min_dist = min_dist_current
if e1_connections[e1_next][0] != e1_current:
e1_current = e1_next
e1_next = e1_connections[e1_next][0]
else:
e1_current = e1_next
e1_next = e1_connections[e1_next][1]
elif (e1_angle > e2_angle) is True:
support_line = Line(e2_next, e2_current)
e2_segment = Segment(e2_current, e2_next)
min_dist_current = e2_segment.distance(e1_current)
if min_dist_current.evalf() < min_dist.evalf():
min_dist = min_dist_current
if e2_connections[e2_next][0] != e2_current:
e2_current = e2_next
e2_next = e2_connections[e2_next][0]
else:
e2_current = e2_next
e2_next = e2_connections[e2_next][1]
else:
support_line = Line(e1_current, e1_next)
e1_segment = Segment(e1_current, e1_next)
e2_segment = Segment(e2_current, e2_next)
min1 = e1_segment.distance(e2_next)
min2 = e2_segment.distance(e1_next)
min_dist_current = min(min1, min2)
if min_dist_current.evalf() < min_dist.evalf():
min_dist = min_dist_current
if e1_connections[e1_next][0] != e1_current:
e1_current = e1_next
e1_next = e1_connections[e1_next][0]
else:
e1_current = e1_next
e1_next = e1_connections[e1_next][1]
if e2_connections[e2_next][0] != e2_current:
e2_current = e2_next
e2_next = e2_connections[e2_next][0]
else:
e2_current = e2_next
e2_next = e2_connections[e2_next][1]
if e1_current == e1_ymax and e2_current == e2_ymin:
break
return min_dist
def _svg(self, scale_factor=1., fill_color="#66cc99"):
"""Returns SVG path element for the Polygon.
Parameters
==========
scale_factor : float
Multiplication factor for the SVG stroke-width. Default is 1.
fill_color : str, optional
Hex string for fill color. Default is "#66cc99".
"""
verts = map(N, self.vertices)
coords = ["{},{}".format(p.x, p.y) for p in verts]
path = "M {} L {} z".format(coords[0], " L ".join(coords[1:]))
return (
'<path fill-rule="evenodd" fill="{2}" stroke="#555555" '
'stroke-width="{0}" opacity="0.6" d="{1}" />'
).format(2. * scale_factor, path, fill_color)
def _hashable_content(self):
D = {}
def ref_list(point_list):
kee = {}
for i, p in enumerate(ordered(set(point_list))):
kee[p] = i
D[i] = p
return [kee[p] for p in point_list]
S1 = ref_list(self.args)
r_nor = rotate_left(S1, least_rotation(S1))
S2 = ref_list(list(reversed(self.args)))
r_rev = rotate_left(S2, least_rotation(S2))
if r_nor < r_rev:
r = r_nor
else:
r = r_rev
canonical_args = [ D[order] for order in r ]
return tuple(canonical_args)
def __contains__(self, o):
"""
Return True if o is contained within the boundary lines of self.altitudes
Parameters
==========
other : GeometryEntity
Returns
=======
contained in : bool
The points (and sides, if applicable) are contained in self.
See Also
========
sympy.geometry.entity.GeometryEntity.encloses
Examples
========
>>> from sympy import Line, Segment, Point
>>> p = Point(0, 0)
>>> q = Point(1, 1)
>>> s = Segment(p, q*2)
>>> l = Line(p, q)
>>> p in q
False
>>> p in s
True
>>> q*3 in s
False
>>> s in l
True
"""
if isinstance(o, Polygon):
return self == o
elif isinstance(o, Segment):
return any(o in s for s in self.sides)
elif isinstance(o, Point):
if o in self.vertices:
return True
for side in self.sides:
if o in side:
return True
return False
def bisectors(p, prec=None):
"""Returns angle bisectors of a polygon. If prec is given
then approximate the point defining the ray to that precision.
The distance between the points defining the bisector ray is 1.
Examples
========
>>> from sympy import Polygon, Point
>>> p = Polygon(Point(0, 0), Point(2, 0), Point(1, 1), Point(0, 3))
>>> p.bisectors(2)
{Point2D(0, 0): Ray2D(Point2D(0, 0), Point2D(0.71, 0.71)),
Point2D(0, 3): Ray2D(Point2D(0, 3), Point2D(0.23, 2.0)),
Point2D(1, 1): Ray2D(Point2D(1, 1), Point2D(0.19, 0.42)),
Point2D(2, 0): Ray2D(Point2D(2, 0), Point2D(1.1, 0.38))}
"""
b = {}
pts = list(p.args)
pts.append(pts[0]) # close it
cw = Polygon._is_clockwise(*pts[:3])
if cw:
pts = list(reversed(pts))
for v, a in p.angles.items():
i = pts.index(v)
p1, p2 = Point._normalize_dimension(pts[i], pts[i + 1])
ray = Ray(p1, p2).rotate(a/2, v)
dir = ray.direction
ray = Ray(ray.p1, ray.p1 + dir/dir.distance((0, 0)))
if prec is not None:
ray = Ray(ray.p1, ray.p2.n(prec))
b[v] = ray
return b
class RegularPolygon(Polygon):
"""
A regular polygon.
Such a polygon has all internal angles equal and all sides the same length.
Parameters
==========
center : Point
radius : number or Basic instance
The distance from the center to a vertex
n : int
The number of sides
Attributes
==========
vertices
center
radius
rotation
apothem
interior_angle
exterior_angle
circumcircle
incircle
angles
Raises
======
GeometryError
If the `center` is not a Point, or the `radius` is not a number or Basic
instance, or the number of sides, `n`, is less than three.
Notes
=====
A RegularPolygon can be instantiated with Polygon with the kwarg n.
Regular polygons are instantiated with a center, radius, number of sides
and a rotation angle. Whereas the arguments of a Polygon are vertices, the
vertices of the RegularPolygon must be obtained with the vertices method.
See Also
========
sympy.geometry.point.Point, Polygon
Examples
========
>>> from sympy import RegularPolygon, Point
>>> r = RegularPolygon(Point(0, 0), 5, 3)
>>> r
RegularPolygon(Point2D(0, 0), 5, 3, 0)
>>> r.vertices[0]
Point2D(5, 0)
"""
__slots__ = ('_n', '_center', '_radius', '_rot')
def __new__(self, c, r, n, rot=0, **kwargs):
r, n, rot = map(sympify, (r, n, rot))
c = Point(c, dim=2, **kwargs)
if not isinstance(r, Expr):
raise GeometryError("r must be an Expr object, not %s" % r)
if n.is_Number:
as_int(n) # let an error raise if necessary
if n < 3:
raise GeometryError("n must be a >= 3, not %s" % n)
obj = GeometryEntity.__new__(self, c, r, n, **kwargs)
obj._n = n
obj._center = c
obj._radius = r
obj._rot = rot % (2*S.Pi/n) if rot.is_number else rot
return obj
def _eval_evalf(self, prec=15, **options):
c, r, n, a = self.args
dps = prec_to_dps(prec)
c, r, a = [i.evalf(n=dps, **options) for i in (c, r, a)]
return self.func(c, r, n, a)
@property
def args(self):
"""
Returns the center point, the radius,
the number of sides, and the orientation angle.
Examples
========
>>> from sympy import RegularPolygon, Point
>>> r = RegularPolygon(Point(0, 0), 5, 3)
>>> r.args
(Point2D(0, 0), 5, 3, 0)
"""
return self._center, self._radius, self._n, self._rot
def __str__(self):
return 'RegularPolygon(%s, %s, %s, %s)' % tuple(self.args)
def __repr__(self):
return 'RegularPolygon(%s, %s, %s, %s)' % tuple(self.args)
@property
def area(self):
"""Returns the area.
Examples
========
>>> from sympy import RegularPolygon
>>> square = RegularPolygon((0, 0), 1, 4)
>>> square.area
2
>>> _ == square.length**2
True
"""
c, r, n, rot = self.args
return sign(r)*n*self.length**2/(4*tan(pi/n))
@property
def length(self):
"""Returns the length of the sides.
The half-length of the side and the apothem form two legs
of a right triangle whose hypotenuse is the radius of the
regular polygon.
Examples
========
>>> from sympy import RegularPolygon
>>> from sympy import sqrt
>>> s = square_in_unit_circle = RegularPolygon((0, 0), 1, 4)
>>> s.length
sqrt(2)
>>> sqrt((_/2)**2 + s.apothem**2) == s.radius
True
"""
return self.radius*2*sin(pi/self._n)
@property
def center(self):
"""The center of the RegularPolygon
This is also the center of the circumscribing circle.
Returns
=======
center : Point
See Also
========
sympy.geometry.point.Point, sympy.geometry.ellipse.Ellipse.center
Examples
========
>>> from sympy import RegularPolygon, Point
>>> rp = RegularPolygon(Point(0, 0), 5, 4)
>>> rp.center
Point2D(0, 0)
"""
return self._center
centroid = center
@property
def circumcenter(self):
"""
Alias for center.
Examples
========
>>> from sympy import RegularPolygon, Point
>>> rp = RegularPolygon(Point(0, 0), 5, 4)
>>> rp.circumcenter
Point2D(0, 0)
"""
return self.center
@property
def radius(self):
"""Radius of the RegularPolygon
This is also the radius of the circumscribing circle.
Returns
=======
radius : number or instance of Basic
See Also
========
sympy.geometry.line.Segment.length, sympy.geometry.ellipse.Circle.radius
Examples
========
>>> from sympy import Symbol
>>> from sympy import RegularPolygon, Point
>>> radius = Symbol('r')
>>> rp = RegularPolygon(Point(0, 0), radius, 4)
>>> rp.radius
r
"""
return self._radius
@property
def circumradius(self):
"""
Alias for radius.
Examples
========
>>> from sympy import Symbol
>>> from sympy import RegularPolygon, Point
>>> radius = Symbol('r')
>>> rp = RegularPolygon(Point(0, 0), radius, 4)
>>> rp.circumradius
r
"""
return self.radius
@property
def rotation(self):
"""CCW angle by which the RegularPolygon is rotated
Returns
=======
rotation : number or instance of Basic
Examples
========
>>> from sympy import pi
>>> from sympy.abc import a
>>> from sympy import RegularPolygon, Point
>>> RegularPolygon(Point(0, 0), 3, 4, pi/4).rotation
pi/4
Numerical rotation angles are made canonical:
>>> RegularPolygon(Point(0, 0), 3, 4, a).rotation
a
>>> RegularPolygon(Point(0, 0), 3, 4, pi).rotation
0
"""
return self._rot
@property
def apothem(self):
"""The inradius of the RegularPolygon.
The apothem/inradius is the radius of the inscribed circle.
Returns
=======
apothem : number or instance of Basic
See Also
========
sympy.geometry.line.Segment.length, sympy.geometry.ellipse.Circle.radius
Examples
========
>>> from sympy import Symbol
>>> from sympy import RegularPolygon, Point
>>> radius = Symbol('r')
>>> rp = RegularPolygon(Point(0, 0), radius, 4)
>>> rp.apothem
sqrt(2)*r/2
"""
return self.radius * cos(S.Pi/self._n)
@property
def inradius(self):
"""
Alias for apothem.
Examples
========
>>> from sympy import Symbol
>>> from sympy import RegularPolygon, Point
>>> radius = Symbol('r')
>>> rp = RegularPolygon(Point(0, 0), radius, 4)
>>> rp.inradius
sqrt(2)*r/2
"""
return self.apothem
@property
def interior_angle(self):
"""Measure of the interior angles.
Returns
=======
interior_angle : number
See Also
========
sympy.geometry.line.LinearEntity.angle_between
Examples
========
>>> from sympy import RegularPolygon, Point
>>> rp = RegularPolygon(Point(0, 0), 4, 8)
>>> rp.interior_angle
3*pi/4
"""
return (self._n - 2)*S.Pi/self._n
@property
def exterior_angle(self):
"""Measure of the exterior angles.
Returns
=======
exterior_angle : number
See Also
========
sympy.geometry.line.LinearEntity.angle_between
Examples
========
>>> from sympy import RegularPolygon, Point
>>> rp = RegularPolygon(Point(0, 0), 4, 8)
>>> rp.exterior_angle
pi/4
"""
return 2*S.Pi/self._n
@property
def circumcircle(self):
"""The circumcircle of the RegularPolygon.
Returns
=======
circumcircle : Circle
See Also
========
circumcenter, sympy.geometry.ellipse.Circle
Examples
========
>>> from sympy import RegularPolygon, Point
>>> rp = RegularPolygon(Point(0, 0), 4, 8)
>>> rp.circumcircle
Circle(Point2D(0, 0), 4)
"""
return Circle(self.center, self.radius)
@property
def incircle(self):
"""The incircle of the RegularPolygon.
Returns
=======
incircle : Circle
See Also
========
inradius, sympy.geometry.ellipse.Circle
Examples
========
>>> from sympy import RegularPolygon, Point
>>> rp = RegularPolygon(Point(0, 0), 4, 7)
>>> rp.incircle
Circle(Point2D(0, 0), 4*cos(pi/7))
"""
return Circle(self.center, self.apothem)
@property
def angles(self):
"""
Returns a dictionary with keys, the vertices of the Polygon,
and values, the interior angle at each vertex.
Examples
========
>>> from sympy import RegularPolygon, Point
>>> r = RegularPolygon(Point(0, 0), 5, 3)
>>> r.angles
{Point2D(-5/2, -5*sqrt(3)/2): pi/3,
Point2D(-5/2, 5*sqrt(3)/2): pi/3,
Point2D(5, 0): pi/3}
"""
ret = {}
ang = self.interior_angle
for v in self.vertices:
ret[v] = ang
return ret
def encloses_point(self, p):
"""
Return True if p is enclosed by (is inside of) self.
Notes
=====
Being on the border of self is considered False.
The general Polygon.encloses_point method is called only if
a point is not within or beyond the incircle or circumcircle,
respectively.
Parameters
==========
p : Point
Returns
=======
encloses_point : True, False or None
See Also
========
sympy.geometry.ellipse.Ellipse.encloses_point
Examples
========
>>> from sympy import RegularPolygon, S, Point, Symbol
>>> p = RegularPolygon((0, 0), 3, 4)
>>> p.encloses_point(Point(0, 0))
True
>>> r, R = p.inradius, p.circumradius
>>> p.encloses_point(Point((r + R)/2, 0))
True
>>> p.encloses_point(Point(R/2, R/2 + (R - r)/10))
False
>>> t = Symbol('t', real=True)
>>> p.encloses_point(p.arbitrary_point().subs(t, S.Half))
False
>>> p.encloses_point(Point(5, 5))
False
"""
c = self.center
d = Segment(c, p).length
if d >= self.radius:
return False
elif d < self.inradius:
return True
else:
# now enumerate the RegularPolygon like a general polygon.
return Polygon.encloses_point(self, p)
def spin(self, angle):
"""Increment *in place* the virtual Polygon's rotation by ccw angle.
See also: rotate method which moves the center.
>>> from sympy import Polygon, Point, pi
>>> r = Polygon(Point(0,0), 1, n=3)
>>> r.vertices[0]
Point2D(1, 0)
>>> r.spin(pi/6)
>>> r.vertices[0]
Point2D(sqrt(3)/2, 1/2)
See Also
========
rotation
rotate : Creates a copy of the RegularPolygon rotated about a Point
"""
self._rot += angle
def rotate(self, angle, pt=None):
"""Override GeometryEntity.rotate to first rotate the RegularPolygon
about its center.
>>> from sympy import Point, RegularPolygon, pi
>>> t = RegularPolygon(Point(1, 0), 1, 3)
>>> t.vertices[0] # vertex on x-axis
Point2D(2, 0)
>>> t.rotate(pi/2).vertices[0] # vertex on y axis now
Point2D(0, 2)
See Also
========
rotation
spin : Rotates a RegularPolygon in place
"""
r = type(self)(*self.args) # need a copy or else changes are in-place
r._rot += angle
return GeometryEntity.rotate(r, angle, pt)
def scale(self, x=1, y=1, pt=None):
"""Override GeometryEntity.scale since it is the radius that must be
scaled (if x == y) or else a new Polygon must be returned.
>>> from sympy import RegularPolygon
Symmetric scaling returns a RegularPolygon:
>>> RegularPolygon((0, 0), 1, 4).scale(2, 2)
RegularPolygon(Point2D(0, 0), 2, 4, 0)
Asymmetric scaling returns a kite as a Polygon:
>>> RegularPolygon((0, 0), 1, 4).scale(2, 1)
Polygon(Point2D(2, 0), Point2D(0, 1), Point2D(-2, 0), Point2D(0, -1))
"""
if pt:
pt = Point(pt, dim=2)
return self.translate(*(-pt).args).scale(x, y).translate(*pt.args)
if x != y:
return Polygon(*self.vertices).scale(x, y)
c, r, n, rot = self.args
r *= x
return self.func(c, r, n, rot)
def reflect(self, line):
"""Override GeometryEntity.reflect since this is not made of only
points.
Examples
========
>>> from sympy import RegularPolygon, Line
>>> RegularPolygon((0, 0), 1, 4).reflect(Line((0, 1), slope=-2))
RegularPolygon(Point2D(4/5, 2/5), -1, 4, atan(4/3))
"""
c, r, n, rot = self.args
v = self.vertices[0]
d = v - c
cc = c.reflect(line)
vv = v.reflect(line)
dd = vv - cc
# calculate rotation about the new center
# which will align the vertices
l1 = Ray((0, 0), dd)
l2 = Ray((0, 0), d)
ang = l1.closing_angle(l2)
rot += ang
# change sign of radius as point traversal is reversed
return self.func(cc, -r, n, rot)
@property
def vertices(self):
"""The vertices of the RegularPolygon.
Returns
=======
vertices : list
Each vertex is a Point.
See Also
========
sympy.geometry.point.Point
Examples
========
>>> from sympy import RegularPolygon, Point
>>> rp = RegularPolygon(Point(0, 0), 5, 4)
>>> rp.vertices
[Point2D(5, 0), Point2D(0, 5), Point2D(-5, 0), Point2D(0, -5)]
"""
c = self._center
r = abs(self._radius)
rot = self._rot
v = 2*S.Pi/self._n
return [Point(c.x + r*cos(k*v + rot), c.y + r*sin(k*v + rot))
for k in range(self._n)]
def __eq__(self, o):
if not isinstance(o, Polygon):
return False
elif not isinstance(o, RegularPolygon):
return Polygon.__eq__(o, self)
return self.args == o.args
def __hash__(self):
return super().__hash__()
class Triangle(Polygon):
"""
A polygon with three vertices and three sides.
Parameters
==========
points : sequence of Points
keyword: asa, sas, or sss to specify sides/angles of the triangle
Attributes
==========
vertices
altitudes
orthocenter
circumcenter
circumradius
circumcircle
inradius
incircle
exradii
medians
medial
nine_point_circle
Raises
======
GeometryError
If the number of vertices is not equal to three, or one of the vertices
is not a Point, or a valid keyword is not given.
See Also
========
sympy.geometry.point.Point, Polygon
Examples
========
>>> from sympy import Triangle, Point
>>> Triangle(Point(0, 0), Point(4, 0), Point(4, 3))
Triangle(Point2D(0, 0), Point2D(4, 0), Point2D(4, 3))
Keywords sss, sas, or asa can be used to give the desired
side lengths (in order) and interior angles (in degrees) that
define the triangle:
>>> Triangle(sss=(3, 4, 5))
Triangle(Point2D(0, 0), Point2D(3, 0), Point2D(3, 4))
>>> Triangle(asa=(30, 1, 30))
Triangle(Point2D(0, 0), Point2D(1, 0), Point2D(1/2, sqrt(3)/6))
>>> Triangle(sas=(1, 45, 2))
Triangle(Point2D(0, 0), Point2D(2, 0), Point2D(sqrt(2)/2, sqrt(2)/2))
"""
def __new__(cls, *args, **kwargs):
if len(args) != 3:
if 'sss' in kwargs:
return _sss(*[simplify(a) for a in kwargs['sss']])
if 'asa' in kwargs:
return _asa(*[simplify(a) for a in kwargs['asa']])
if 'sas' in kwargs:
return _sas(*[simplify(a) for a in kwargs['sas']])
msg = "Triangle instantiates with three points or a valid keyword."
raise GeometryError(msg)
vertices = [Point(a, dim=2, **kwargs) for a in args]
# remove consecutive duplicates
nodup = []
for p in vertices:
if nodup and p == nodup[-1]:
continue
nodup.append(p)
if len(nodup) > 1 and nodup[-1] == nodup[0]:
nodup.pop() # last point was same as first
# remove collinear points
i = -3
while i < len(nodup) - 3 and len(nodup) > 2:
a, b, c = sorted(
[nodup[i], nodup[i + 1], nodup[i + 2]], key=default_sort_key)
if Point.is_collinear(a, b, c):
nodup[i] = a
nodup[i + 1] = None
nodup.pop(i + 1)
i += 1
vertices = list(filter(lambda x: x is not None, nodup))
if len(vertices) == 3:
return GeometryEntity.__new__(cls, *vertices, **kwargs)
elif len(vertices) == 2:
return Segment(*vertices, **kwargs)
else:
return Point(*vertices, **kwargs)
@property
def vertices(self):
"""The triangle's vertices
Returns
=======
vertices : tuple
Each element in the tuple is a Point
See Also
========
sympy.geometry.point.Point
Examples
========
>>> from sympy import Triangle, Point
>>> t = Triangle(Point(0, 0), Point(4, 0), Point(4, 3))
>>> t.vertices
(Point2D(0, 0), Point2D(4, 0), Point2D(4, 3))
"""
return self.args
def is_similar(t1, t2):
"""Is another triangle similar to this one.
Two triangles are similar if one can be uniformly scaled to the other.
Parameters
==========
other: Triangle
Returns
=======
is_similar : boolean
See Also
========
sympy.geometry.entity.GeometryEntity.is_similar
Examples
========
>>> from sympy import Triangle, Point
>>> t1 = Triangle(Point(0, 0), Point(4, 0), Point(4, 3))
>>> t2 = Triangle(Point(0, 0), Point(-4, 0), Point(-4, -3))
>>> t1.is_similar(t2)
True
>>> t2 = Triangle(Point(0, 0), Point(-4, 0), Point(-4, -4))
>>> t1.is_similar(t2)
False
"""
if not isinstance(t2, Polygon):
return False
s1_1, s1_2, s1_3 = [side.length for side in t1.sides]
s2 = [side.length for side in t2.sides]
def _are_similar(u1, u2, u3, v1, v2, v3):
e1 = simplify(u1/v1)
e2 = simplify(u2/v2)
e3 = simplify(u3/v3)
return bool(e1 == e2) and bool(e2 == e3)
# There's only 6 permutations, so write them out
return _are_similar(s1_1, s1_2, s1_3, *s2) or \
_are_similar(s1_1, s1_3, s1_2, *s2) or \
_are_similar(s1_2, s1_1, s1_3, *s2) or \
_are_similar(s1_2, s1_3, s1_1, *s2) or \
_are_similar(s1_3, s1_1, s1_2, *s2) or \
_are_similar(s1_3, s1_2, s1_1, *s2)
def is_equilateral(self):
"""Are all the sides the same length?
Returns
=======
is_equilateral : boolean
See Also
========
sympy.geometry.entity.GeometryEntity.is_similar, RegularPolygon
is_isosceles, is_right, is_scalene
Examples
========
>>> from sympy import Triangle, Point
>>> t1 = Triangle(Point(0, 0), Point(4, 0), Point(4, 3))
>>> t1.is_equilateral()
False
>>> from sympy import sqrt
>>> t2 = Triangle(Point(0, 0), Point(10, 0), Point(5, 5*sqrt(3)))
>>> t2.is_equilateral()
True
"""
return not has_variety(s.length for s in self.sides)
def is_isosceles(self):
"""Are two or more of the sides the same length?
Returns
=======
is_isosceles : boolean
See Also
========
is_equilateral, is_right, is_scalene
Examples
========
>>> from sympy import Triangle, Point
>>> t1 = Triangle(Point(0, 0), Point(4, 0), Point(2, 4))
>>> t1.is_isosceles()
True
"""
return has_dups(s.length for s in self.sides)
def is_scalene(self):
"""Are all the sides of the triangle of different lengths?
Returns
=======
is_scalene : boolean
See Also
========
is_equilateral, is_isosceles, is_right
Examples
========
>>> from sympy import Triangle, Point
>>> t1 = Triangle(Point(0, 0), Point(4, 0), Point(1, 4))
>>> t1.is_scalene()
True
"""
return not has_dups(s.length for s in self.sides)
def is_right(self):
"""Is the triangle right-angled.
Returns
=======
is_right : boolean
See Also
========
sympy.geometry.line.LinearEntity.is_perpendicular
is_equilateral, is_isosceles, is_scalene
Examples
========
>>> from sympy import Triangle, Point
>>> t1 = Triangle(Point(0, 0), Point(4, 0), Point(4, 3))
>>> t1.is_right()
True
"""
s = self.sides
return Segment.is_perpendicular(s[0], s[1]) or \
Segment.is_perpendicular(s[1], s[2]) or \
Segment.is_perpendicular(s[0], s[2])
@property
def altitudes(self):
"""The altitudes of the triangle.
An altitude of a triangle is a segment through a vertex,
perpendicular to the opposite side, with length being the
height of the vertex measured from the line containing the side.
Returns
=======
altitudes : dict
The dictionary consists of keys which are vertices and values
which are Segments.
See Also
========
sympy.geometry.point.Point, sympy.geometry.line.Segment.length
Examples
========
>>> from sympy import Point, Triangle
>>> p1, p2, p3 = Point(0, 0), Point(1, 0), Point(0, 1)
>>> t = Triangle(p1, p2, p3)
>>> t.altitudes[p1]
Segment2D(Point2D(0, 0), Point2D(1/2, 1/2))
"""
s = self.sides
v = self.vertices
return {v[0]: s[1].perpendicular_segment(v[0]),
v[1]: s[2].perpendicular_segment(v[1]),
v[2]: s[0].perpendicular_segment(v[2])}
@property
def orthocenter(self):
"""The orthocenter of the triangle.
The orthocenter is the intersection of the altitudes of a triangle.
It may lie inside, outside or on the triangle.
Returns
=======
orthocenter : Point
See Also
========
sympy.geometry.point.Point
Examples
========
>>> from sympy import Point, Triangle
>>> p1, p2, p3 = Point(0, 0), Point(1, 0), Point(0, 1)
>>> t = Triangle(p1, p2, p3)
>>> t.orthocenter
Point2D(0, 0)
"""
a = self.altitudes
v = self.vertices
return Line(a[v[0]]).intersection(Line(a[v[1]]))[0]
@property
def circumcenter(self):
"""The circumcenter of the triangle
The circumcenter is the center of the circumcircle.
Returns
=======
circumcenter : Point
See Also
========
sympy.geometry.point.Point
Examples
========
>>> from sympy import Point, Triangle
>>> p1, p2, p3 = Point(0, 0), Point(1, 0), Point(0, 1)
>>> t = Triangle(p1, p2, p3)
>>> t.circumcenter
Point2D(1/2, 1/2)
"""
a, b, c = [x.perpendicular_bisector() for x in self.sides]
return a.intersection(b)[0]
@property
def circumradius(self):
"""The radius of the circumcircle of the triangle.
Returns
=======
circumradius : number of Basic instance
See Also
========
sympy.geometry.ellipse.Circle.radius
Examples
========
>>> from sympy import Symbol
>>> from sympy import Point, Triangle
>>> a = Symbol('a')
>>> p1, p2, p3 = Point(0, 0), Point(1, 0), Point(0, a)
>>> t = Triangle(p1, p2, p3)
>>> t.circumradius
sqrt(a**2/4 + 1/4)
"""
return Point.distance(self.circumcenter, self.vertices[0])
@property
def circumcircle(self):
"""The circle which passes through the three vertices of the triangle.
Returns
=======
circumcircle : Circle
See Also
========
sympy.geometry.ellipse.Circle
Examples
========
>>> from sympy import Point, Triangle
>>> p1, p2, p3 = Point(0, 0), Point(1, 0), Point(0, 1)
>>> t = Triangle(p1, p2, p3)
>>> t.circumcircle
Circle(Point2D(1/2, 1/2), sqrt(2)/2)
"""
return Circle(self.circumcenter, self.circumradius)
def bisectors(self):
"""The angle bisectors of the triangle.
An angle bisector of a triangle is a straight line through a vertex
which cuts the corresponding angle in half.
Returns
=======
bisectors : dict
Each key is a vertex (Point) and each value is the corresponding
bisector (Segment).
See Also
========
sympy.geometry.point.Point, sympy.geometry.line.Segment
Examples
========
>>> from sympy import Point, Triangle, Segment
>>> p1, p2, p3 = Point(0, 0), Point(1, 0), Point(0, 1)
>>> t = Triangle(p1, p2, p3)
>>> from sympy import sqrt
>>> t.bisectors()[p2] == Segment(Point(1, 0), Point(0, sqrt(2) - 1))
True
"""
# use lines containing sides so containment check during
# intersection calculation can be avoided, thus reducing
# the processing time for calculating the bisectors
s = [Line(l) for l in self.sides]
v = self.vertices
c = self.incenter
l1 = Segment(v[0], Line(v[0], c).intersection(s[1])[0])
l2 = Segment(v[1], Line(v[1], c).intersection(s[2])[0])
l3 = Segment(v[2], Line(v[2], c).intersection(s[0])[0])
return {v[0]: l1, v[1]: l2, v[2]: l3}
@property
def incenter(self):
"""The center of the incircle.
The incircle is the circle which lies inside the triangle and touches
all three sides.
Returns
=======
incenter : Point
See Also
========
incircle, sympy.geometry.point.Point
Examples
========
>>> from sympy import Point, Triangle
>>> p1, p2, p3 = Point(0, 0), Point(1, 0), Point(0, 1)
>>> t = Triangle(p1, p2, p3)
>>> t.incenter
Point2D(1 - sqrt(2)/2, 1 - sqrt(2)/2)
"""
s = self.sides
l = Matrix([s[i].length for i in [1, 2, 0]])
p = sum(l)
v = self.vertices
x = simplify(l.dot(Matrix([vi.x for vi in v]))/p)
y = simplify(l.dot(Matrix([vi.y for vi in v]))/p)
return Point(x, y)
@property
def inradius(self):
"""The radius of the incircle.
Returns
=======
inradius : number of Basic instance
See Also
========
incircle, sympy.geometry.ellipse.Circle.radius
Examples
========
>>> from sympy import Point, Triangle
>>> p1, p2, p3 = Point(0, 0), Point(4, 0), Point(0, 3)
>>> t = Triangle(p1, p2, p3)
>>> t.inradius
1
"""
return simplify(2 * self.area / self.perimeter)
@property
def incircle(self):
"""The incircle of the triangle.
The incircle is the circle which lies inside the triangle and touches
all three sides.
Returns
=======
incircle : Circle
See Also
========
sympy.geometry.ellipse.Circle
Examples
========
>>> from sympy import Point, Triangle
>>> p1, p2, p3 = Point(0, 0), Point(2, 0), Point(0, 2)
>>> t = Triangle(p1, p2, p3)
>>> t.incircle
Circle(Point2D(2 - sqrt(2), 2 - sqrt(2)), 2 - sqrt(2))
"""
return Circle(self.incenter, self.inradius)
@property
def exradii(self):
"""The radius of excircles of a triangle.
An excircle of the triangle is a circle lying outside the triangle,
tangent to one of its sides and tangent to the extensions of the
other two.
Returns
=======
exradii : dict
See Also
========
sympy.geometry.polygon.Triangle.inradius
Examples
========
The exradius touches the side of the triangle to which it is keyed, e.g.
the exradius touching side 2 is:
>>> from sympy import Point, Triangle
>>> p1, p2, p3 = Point(0, 0), Point(6, 0), Point(0, 2)
>>> t = Triangle(p1, p2, p3)
>>> t.exradii[t.sides[2]]
-2 + sqrt(10)
References
==========
.. [1] https://mathworld.wolfram.com/Exradius.html
.. [2] https://mathworld.wolfram.com/Excircles.html
"""
side = self.sides
a = side[0].length
b = side[1].length
c = side[2].length
s = (a+b+c)/2
area = self.area
exradii = {self.sides[0]: simplify(area/(s-a)),
self.sides[1]: simplify(area/(s-b)),
self.sides[2]: simplify(area/(s-c))}
return exradii
@property
def excenters(self):
"""Excenters of the triangle.
An excenter is the center of a circle that is tangent to a side of the
triangle and the extensions of the other two sides.
Returns
=======
excenters : dict
Examples
========
The excenters are keyed to the side of the triangle to which their corresponding
excircle is tangent: The center is keyed, e.g. the excenter of a circle touching
side 0 is:
>>> from sympy import Point, Triangle
>>> p1, p2, p3 = Point(0, 0), Point(6, 0), Point(0, 2)
>>> t = Triangle(p1, p2, p3)
>>> t.excenters[t.sides[0]]
Point2D(12*sqrt(10), 2/3 + sqrt(10)/3)
See Also
========
sympy.geometry.polygon.Triangle.exradii
References
==========
.. [1] https://mathworld.wolfram.com/Excircles.html
"""
s = self.sides
v = self.vertices
a = s[0].length
b = s[1].length
c = s[2].length
x = [v[0].x, v[1].x, v[2].x]
y = [v[0].y, v[1].y, v[2].y]
exc_coords = {
"x1": simplify(-a*x[0]+b*x[1]+c*x[2]/(-a+b+c)),
"x2": simplify(a*x[0]-b*x[1]+c*x[2]/(a-b+c)),
"x3": simplify(a*x[0]+b*x[1]-c*x[2]/(a+b-c)),
"y1": simplify(-a*y[0]+b*y[1]+c*y[2]/(-a+b+c)),
"y2": simplify(a*y[0]-b*y[1]+c*y[2]/(a-b+c)),
"y3": simplify(a*y[0]+b*y[1]-c*y[2]/(a+b-c))
}
excenters = {
s[0]: Point(exc_coords["x1"], exc_coords["y1"]),
s[1]: Point(exc_coords["x2"], exc_coords["y2"]),
s[2]: Point(exc_coords["x3"], exc_coords["y3"])
}
return excenters
@property
def medians(self):
"""The medians of the triangle.
A median of a triangle is a straight line through a vertex and the
midpoint of the opposite side, and divides the triangle into two
equal areas.
Returns
=======
medians : dict
Each key is a vertex (Point) and each value is the median (Segment)
at that point.
See Also
========
sympy.geometry.point.Point.midpoint, sympy.geometry.line.Segment.midpoint
Examples
========
>>> from sympy import Point, Triangle
>>> p1, p2, p3 = Point(0, 0), Point(1, 0), Point(0, 1)
>>> t = Triangle(p1, p2, p3)
>>> t.medians[p1]
Segment2D(Point2D(0, 0), Point2D(1/2, 1/2))
"""
s = self.sides
v = self.vertices
return {v[0]: Segment(v[0], s[1].midpoint),
v[1]: Segment(v[1], s[2].midpoint),
v[2]: Segment(v[2], s[0].midpoint)}
@property
def medial(self):
"""The medial triangle of the triangle.
The triangle which is formed from the midpoints of the three sides.
Returns
=======
medial : Triangle
See Also
========
sympy.geometry.line.Segment.midpoint
Examples
========
>>> from sympy import Point, Triangle
>>> p1, p2, p3 = Point(0, 0), Point(1, 0), Point(0, 1)
>>> t = Triangle(p1, p2, p3)
>>> t.medial
Triangle(Point2D(1/2, 0), Point2D(1/2, 1/2), Point2D(0, 1/2))
"""
s = self.sides
return Triangle(s[0].midpoint, s[1].midpoint, s[2].midpoint)
@property
def nine_point_circle(self):
"""The nine-point circle of the triangle.
Nine-point circle is the circumcircle of the medial triangle, which
passes through the feet of altitudes and the middle points of segments
connecting the vertices and the orthocenter.
Returns
=======
nine_point_circle : Circle
See also
========
sympy.geometry.line.Segment.midpoint
sympy.geometry.polygon.Triangle.medial
sympy.geometry.polygon.Triangle.orthocenter
Examples
========
>>> from sympy import Point, Triangle
>>> p1, p2, p3 = Point(0, 0), Point(1, 0), Point(0, 1)
>>> t = Triangle(p1, p2, p3)
>>> t.nine_point_circle
Circle(Point2D(1/4, 1/4), sqrt(2)/4)
"""
return Circle(*self.medial.vertices)
@property
def eulerline(self):
"""The Euler line of the triangle.
The line which passes through circumcenter, centroid and orthocenter.
Returns
=======
eulerline : Line (or Point for equilateral triangles in which case all
centers coincide)
Examples
========
>>> from sympy import Point, Triangle
>>> p1, p2, p3 = Point(0, 0), Point(1, 0), Point(0, 1)
>>> t = Triangle(p1, p2, p3)
>>> t.eulerline
Line2D(Point2D(0, 0), Point2D(1/2, 1/2))
"""
if self.is_equilateral():
return self.orthocenter
return Line(self.orthocenter, self.circumcenter)
def rad(d):
"""Return the radian value for the given degrees (pi = 180 degrees)."""
return d*pi/180
def deg(r):
"""Return the degree value for the given radians (pi = 180 degrees)."""
return r/pi*180
def _slope(d):
rv = tan(rad(d))
return rv
def _asa(d1, l, d2):
"""Return triangle having side with length l on the x-axis."""
xy = Line((0, 0), slope=_slope(d1)).intersection(
Line((l, 0), slope=_slope(180 - d2)))[0]
return Triangle((0, 0), (l, 0), xy)
def _sss(l1, l2, l3):
"""Return triangle having side of length l1 on the x-axis."""
c1 = Circle((0, 0), l3)
c2 = Circle((l1, 0), l2)
inter = [a for a in c1.intersection(c2) if a.y.is_nonnegative]
if not inter:
return None
pt = inter[0]
return Triangle((0, 0), (l1, 0), pt)
def _sas(l1, d, l2):
"""Return triangle having side with length l2 on the x-axis."""
p1 = Point(0, 0)
p2 = Point(l2, 0)
p3 = Point(cos(rad(d))*l1, sin(rad(d))*l1)
return Triangle(p1, p2, p3)
PK ]ZZZ��>��P �P sympy/geometry/util.py"""Utility functions for geometrical entities.
Contains
========
intersection
convex_hull
closest_points
farthest_points
are_coplanar
are_similar
"""
from collections import deque
from math import sqrt as _sqrt
from sympy import nsimplify
from .entity import GeometryEntity
from .exceptions import GeometryError
from .point import Point, Point2D, Point3D
from sympy.core.containers import OrderedSet
from sympy.core.exprtools import factor_terms
from sympy.core.function import Function, expand_mul
from sympy.core.numbers import Float
from sympy.core.sorting import ordered
from sympy.core.symbol import Symbol
from sympy.core.singleton import S
from sympy.polys.polytools import cancel
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.utilities.iterables import is_sequence
from mpmath.libmp.libmpf import prec_to_dps
def find(x, equation):
"""
Checks whether a Symbol matching ``x`` is present in ``equation``
or not. If present, the matching symbol is returned, else a
ValueError is raised. If ``x`` is a string the matching symbol
will have the same name; if ``x`` is a Symbol then it will be
returned if found.
Examples
========
>>> from sympy.geometry.util import find
>>> from sympy import Dummy
>>> from sympy.abc import x
>>> find('x', x)
x
>>> find('x', Dummy('x'))
_x
The dummy symbol is returned since it has a matching name:
>>> _.name == 'x'
True
>>> find(x, Dummy('x'))
Traceback (most recent call last):
...
ValueError: could not find x
"""
free = equation.free_symbols
xs = [i for i in free if (i.name if isinstance(x, str) else i) == x]
if not xs:
raise ValueError('could not find %s' % x)
if len(xs) != 1:
raise ValueError('ambiguous %s' % x)
return xs[0]
def _ordered_points(p):
"""Return the tuple of points sorted numerically according to args"""
return tuple(sorted(p, key=lambda x: x.args))
def are_coplanar(*e):
""" Returns True if the given entities are coplanar otherwise False
Parameters
==========
e: entities to be checked for being coplanar
Returns
=======
Boolean
Examples
========
>>> from sympy import Point3D, Line3D
>>> from sympy.geometry.util import are_coplanar
>>> a = Line3D(Point3D(5, 0, 0), Point3D(1, -1, 1))
>>> b = Line3D(Point3D(0, -2, 0), Point3D(3, 1, 1))
>>> c = Line3D(Point3D(0, -1, 0), Point3D(5, -1, 9))
>>> are_coplanar(a, b, c)
False
"""
from .line import LinearEntity3D
from .plane import Plane
# XXX update tests for coverage
e = set(e)
# first work with a Plane if present
for i in list(e):
if isinstance(i, Plane):
e.remove(i)
return all(p.is_coplanar(i) for p in e)
if all(isinstance(i, Point3D) for i in e):
if len(e) < 3:
return False
# remove pts that are collinear with 2 pts
a, b = e.pop(), e.pop()
for i in list(e):
if Point3D.are_collinear(a, b, i):
e.remove(i)
if not e:
return False
else:
# define a plane
p = Plane(a, b, e.pop())
for i in e:
if i not in p:
return False
return True
else:
pt3d = []
for i in e:
if isinstance(i, Point3D):
pt3d.append(i)
elif isinstance(i, LinearEntity3D):
pt3d.extend(i.args)
elif isinstance(i, GeometryEntity): # XXX we should have a GeometryEntity3D class so we can tell the difference between 2D and 3D -- here we just want to deal with 2D objects; if new 3D objects are encountered that we didn't handle above, an error should be raised
# all 2D objects have some Point that defines them; so convert those points to 3D pts by making z=0
for p in i.args:
if isinstance(p, Point):
pt3d.append(Point3D(*(p.args + (0,))))
return are_coplanar(*pt3d)
def are_similar(e1, e2):
"""Are two geometrical entities similar.
Can one geometrical entity be uniformly scaled to the other?
Parameters
==========
e1 : GeometryEntity
e2 : GeometryEntity
Returns
=======
are_similar : boolean
Raises
======
GeometryError
When `e1` and `e2` cannot be compared.
Notes
=====
If the two objects are equal then they are similar.
See Also
========
sympy.geometry.entity.GeometryEntity.is_similar
Examples
========
>>> from sympy import Point, Circle, Triangle, are_similar
>>> c1, c2 = Circle(Point(0, 0), 4), Circle(Point(1, 4), 3)
>>> t1 = Triangle(Point(0, 0), Point(1, 0), Point(0, 1))
>>> t2 = Triangle(Point(0, 0), Point(2, 0), Point(0, 2))
>>> t3 = Triangle(Point(0, 0), Point(3, 0), Point(0, 1))
>>> are_similar(t1, t2)
True
>>> are_similar(t1, t3)
False
"""
if e1 == e2:
return True
is_similar1 = getattr(e1, 'is_similar', None)
if is_similar1:
return is_similar1(e2)
is_similar2 = getattr(e2, 'is_similar', None)
if is_similar2:
return is_similar2(e1)
n1 = e1.__class__.__name__
n2 = e2.__class__.__name__
raise GeometryError(
"Cannot test similarity between %s and %s" % (n1, n2))
def centroid(*args):
"""Find the centroid (center of mass) of the collection containing only Points,
Segments or Polygons. The centroid is the weighted average of the individual centroid
where the weights are the lengths (of segments) or areas (of polygons).
Overlapping regions will add to the weight of that region.
If there are no objects (or a mixture of objects) then None is returned.
See Also
========
sympy.geometry.point.Point, sympy.geometry.line.Segment,
sympy.geometry.polygon.Polygon
Examples
========
>>> from sympy import Point, Segment, Polygon
>>> from sympy.geometry.util import centroid
>>> p = Polygon((0, 0), (10, 0), (10, 10))
>>> q = p.translate(0, 20)
>>> p.centroid, q.centroid
(Point2D(20/3, 10/3), Point2D(20/3, 70/3))
>>> centroid(p, q)
Point2D(20/3, 40/3)
>>> p, q = Segment((0, 0), (2, 0)), Segment((0, 0), (2, 2))
>>> centroid(p, q)
Point2D(1, 2 - sqrt(2))
>>> centroid(Point(0, 0), Point(2, 0))
Point2D(1, 0)
Stacking 3 polygons on top of each other effectively triples the
weight of that polygon:
>>> p = Polygon((0, 0), (1, 0), (1, 1), (0, 1))
>>> q = Polygon((1, 0), (3, 0), (3, 1), (1, 1))
>>> centroid(p, q)
Point2D(3/2, 1/2)
>>> centroid(p, p, p, q) # centroid x-coord shifts left
Point2D(11/10, 1/2)
Stacking the squares vertically above and below p has the same
effect:
>>> centroid(p, p.translate(0, 1), p.translate(0, -1), q)
Point2D(11/10, 1/2)
"""
from .line import Segment
from .polygon import Polygon
if args:
if all(isinstance(g, Point) for g in args):
c = Point(0, 0)
for g in args:
c += g
den = len(args)
elif all(isinstance(g, Segment) for g in args):
c = Point(0, 0)
L = 0
for g in args:
l = g.length
c += g.midpoint*l
L += l
den = L
elif all(isinstance(g, Polygon) for g in args):
c = Point(0, 0)
A = 0
for g in args:
a = g.area
c += g.centroid*a
A += a
den = A
c /= den
return c.func(*[i.simplify() for i in c.args])
def closest_points(*args):
"""Return the subset of points from a set of points that were
the closest to each other in the 2D plane.
Parameters
==========
args
A collection of Points on 2D plane.
Notes
=====
This can only be performed on a set of points whose coordinates can
be ordered on the number line. If there are no ties then a single
pair of Points will be in the set.
Examples
========
>>> from sympy import closest_points, Triangle
>>> Triangle(sss=(3, 4, 5)).args
(Point2D(0, 0), Point2D(3, 0), Point2D(3, 4))
>>> closest_points(*_)
{(Point2D(0, 0), Point2D(3, 0))}
References
==========
.. [1] https://www.cs.mcgill.ca/~cs251/ClosestPair/ClosestPairPS.html
.. [2] Sweep line algorithm
https://en.wikipedia.org/wiki/Sweep_line_algorithm
"""
p = [Point2D(i) for i in set(args)]
if len(p) < 2:
raise ValueError('At least 2 distinct points must be given.')
try:
p.sort(key=lambda x: x.args)
except TypeError:
raise ValueError("The points could not be sorted.")
if not all(i.is_Rational for j in p for i in j.args):
def hypot(x, y):
arg = x*x + y*y
if arg.is_Rational:
return _sqrt(arg)
return sqrt(arg)
else:
from math import hypot
rv = [(0, 1)]
best_dist = hypot(p[1].x - p[0].x, p[1].y - p[0].y)
i = 2
left = 0
box = deque([0, 1])
while i < len(p):
while left < i and p[i][0] - p[left][0] > best_dist:
box.popleft()
left += 1
for j in box:
d = hypot(p[i].x - p[j].x, p[i].y - p[j].y)
if d < best_dist:
rv = [(j, i)]
elif d == best_dist:
rv.append((j, i))
else:
continue
best_dist = d
box.append(i)
i += 1
return {tuple([p[i] for i in pair]) for pair in rv}
def convex_hull(*args, polygon=True):
"""The convex hull surrounding the Points contained in the list of entities.
Parameters
==========
args : a collection of Points, Segments and/or Polygons
Optional parameters
===================
polygon : Boolean. If True, returns a Polygon, if false a tuple, see below.
Default is True.
Returns
=======
convex_hull : Polygon if ``polygon`` is True else as a tuple `(U, L)` where
``L`` and ``U`` are the lower and upper hulls, respectively.
Notes
=====
This can only be performed on a set of points whose coordinates can
be ordered on the number line.
See Also
========
sympy.geometry.point.Point, sympy.geometry.polygon.Polygon
Examples
========
>>> from sympy import convex_hull
>>> points = [(1, 1), (1, 2), (3, 1), (-5, 2), (15, 4)]
>>> convex_hull(*points)
Polygon(Point2D(-5, 2), Point2D(1, 1), Point2D(3, 1), Point2D(15, 4))
>>> convex_hull(*points, **dict(polygon=False))
([Point2D(-5, 2), Point2D(15, 4)],
[Point2D(-5, 2), Point2D(1, 1), Point2D(3, 1), Point2D(15, 4)])
References
==========
.. [1] https://en.wikipedia.org/wiki/Graham_scan
.. [2] Andrew's Monotone Chain Algorithm
(A.M. Andrew,
"Another Efficient Algorithm for Convex Hulls in Two Dimensions", 1979)
https://web.archive.org/web/20210511015444/http://geomalgorithms.com/a10-_hull-1.html
"""
from .line import Segment
from .polygon import Polygon
p = OrderedSet()
for e in args:
if not isinstance(e, GeometryEntity):
try:
e = Point(e)
except NotImplementedError:
raise ValueError('%s is not a GeometryEntity and cannot be made into Point' % str(e))
if isinstance(e, Point):
p.add(e)
elif isinstance(e, Segment):
p.update(e.points)
elif isinstance(e, Polygon):
p.update(e.vertices)
else:
raise NotImplementedError(
'Convex hull for %s not implemented.' % type(e))
# make sure all our points are of the same dimension
if any(len(x) != 2 for x in p):
raise ValueError('Can only compute the convex hull in two dimensions')
p = list(p)
if len(p) == 1:
return p[0] if polygon else (p[0], None)
elif len(p) == 2:
s = Segment(p[0], p[1])
return s if polygon else (s, None)
def _orientation(p, q, r):
'''Return positive if p-q-r are clockwise, neg if ccw, zero if
collinear.'''
return (q.y - p.y)*(r.x - p.x) - (q.x - p.x)*(r.y - p.y)
# scan to find upper and lower convex hulls of a set of 2d points.
U = []
L = []
try:
p.sort(key=lambda x: x.args)
except TypeError:
raise ValueError("The points could not be sorted.")
for p_i in p:
while len(U) > 1 and _orientation(U[-2], U[-1], p_i) <= 0:
U.pop()
while len(L) > 1 and _orientation(L[-2], L[-1], p_i) >= 0:
L.pop()
U.append(p_i)
L.append(p_i)
U.reverse()
convexHull = tuple(L + U[1:-1])
if len(convexHull) == 2:
s = Segment(convexHull[0], convexHull[1])
return s if polygon else (s, None)
if polygon:
return Polygon(*convexHull)
else:
U.reverse()
return (U, L)
def farthest_points(*args):
"""Return the subset of points from a set of points that were
the furthest apart from each other in the 2D plane.
Parameters
==========
args
A collection of Points on 2D plane.
Notes
=====
This can only be performed on a set of points whose coordinates can
be ordered on the number line. If there are no ties then a single
pair of Points will be in the set.
Examples
========
>>> from sympy.geometry import farthest_points, Triangle
>>> Triangle(sss=(3, 4, 5)).args
(Point2D(0, 0), Point2D(3, 0), Point2D(3, 4))
>>> farthest_points(*_)
{(Point2D(0, 0), Point2D(3, 4))}
References
==========
.. [1] https://code.activestate.com/recipes/117225-convex-hull-and-diameter-of-2d-point-sets/
.. [2] Rotating Callipers Technique
https://en.wikipedia.org/wiki/Rotating_calipers
"""
def rotatingCalipers(Points):
U, L = convex_hull(*Points, **{"polygon": False})
if L is None:
if isinstance(U, Point):
raise ValueError('At least two distinct points must be given.')
yield U.args
else:
i = 0
j = len(L) - 1
while i < len(U) - 1 or j > 0:
yield U[i], L[j]
# if all the way through one side of hull, advance the other side
if i == len(U) - 1:
j -= 1
elif j == 0:
i += 1
# still points left on both lists, compare slopes of next hull edges
# being careful to avoid divide-by-zero in slope calculation
elif (U[i+1].y - U[i].y) * (L[j].x - L[j-1].x) > \
(L[j].y - L[j-1].y) * (U[i+1].x - U[i].x):
i += 1
else:
j -= 1
p = [Point2D(i) for i in set(args)]
if not all(i.is_Rational for j in p for i in j.args):
def hypot(x, y):
arg = x*x + y*y
if arg.is_Rational:
return _sqrt(arg)
return sqrt(arg)
else:
from math import hypot
rv = []
diam = 0
for pair in rotatingCalipers(args):
h, q = _ordered_points(pair)
d = hypot(h.x - q.x, h.y - q.y)
if d > diam:
rv = [(h, q)]
elif d == diam:
rv.append((h, q))
else:
continue
diam = d
return set(rv)
def idiff(eq, y, x, n=1):
"""Return ``dy/dx`` assuming that ``eq == 0``.
Parameters
==========
y : the dependent variable or a list of dependent variables (with y first)
x : the variable that the derivative is being taken with respect to
n : the order of the derivative (default is 1)
Examples
========
>>> from sympy.abc import x, y, a
>>> from sympy.geometry.util import idiff
>>> circ = x**2 + y**2 - 4
>>> idiff(circ, y, x)
-x/y
>>> idiff(circ, y, x, 2).simplify()
(-x**2 - y**2)/y**3
Here, ``a`` is assumed to be independent of ``x``:
>>> idiff(x + a + y, y, x)
-1
Now the x-dependence of ``a`` is made explicit by listing ``a`` after
``y`` in a list.
>>> idiff(x + a + y, [y, a], x)
-Derivative(a, x) - 1
See Also
========
sympy.core.function.Derivative: represents unevaluated derivatives
sympy.core.function.diff: explicitly differentiates wrt symbols
"""
if is_sequence(y):
dep = set(y)
y = y[0]
elif isinstance(y, Symbol):
dep = {y}
elif isinstance(y, Function):
pass
else:
raise ValueError("expecting x-dependent symbol(s) or function(s) but got: %s" % y)
f = {s: Function(s.name)(x) for s in eq.free_symbols
if s != x and s in dep}
if isinstance(y, Symbol):
dydx = Function(y.name)(x).diff(x)
else:
dydx = y.diff(x)
eq = eq.subs(f)
derivs = {}
for i in range(n):
# equation will be linear in dydx, a*dydx + b, so dydx = -b/a
deq = eq.diff(x)
b = deq.xreplace({dydx: S.Zero})
a = (deq - b).xreplace({dydx: S.One})
yp = factor_terms(expand_mul(cancel((-b/a).subs(derivs)), deep=False))
if i == n - 1:
return yp.subs([(v, k) for k, v in f.items()])
derivs[dydx] = yp
eq = dydx - yp
dydx = dydx.diff(x)
def intersection(*entities, pairwise=False, **kwargs):
"""The intersection of a collection of GeometryEntity instances.
Parameters
==========
entities : sequence of GeometryEntity
pairwise (keyword argument) : Can be either True or False
Returns
=======
intersection : list of GeometryEntity
Raises
======
NotImplementedError
When unable to calculate intersection.
Notes
=====
The intersection of any geometrical entity with itself should return
a list with one item: the entity in question.
An intersection requires two or more entities. If only a single
entity is given then the function will return an empty list.
It is possible for `intersection` to miss intersections that one
knows exists because the required quantities were not fully
simplified internally.
Reals should be converted to Rationals, e.g. Rational(str(real_num))
or else failures due to floating point issues may result.
Case 1: When the keyword argument 'pairwise' is False (default value):
In this case, the function returns a list of intersections common to
all entities.
Case 2: When the keyword argument 'pairwise' is True:
In this case, the functions returns a list intersections that occur
between any pair of entities.
See Also
========
sympy.geometry.entity.GeometryEntity.intersection
Examples
========
>>> from sympy import Ray, Circle, intersection
>>> c = Circle((0, 1), 1)
>>> intersection(c, c.center)
[]
>>> right = Ray((0, 0), (1, 0))
>>> up = Ray((0, 0), (0, 1))
>>> intersection(c, right, up)
[Point2D(0, 0)]
>>> intersection(c, right, up, pairwise=True)
[Point2D(0, 0), Point2D(0, 2)]
>>> left = Ray((1, 0), (0, 0))
>>> intersection(right, left)
[Segment2D(Point2D(0, 0), Point2D(1, 0))]
"""
if len(entities) <= 1:
return []
entities = list(entities)
prec = None
for i, e in enumerate(entities):
if not isinstance(e, GeometryEntity):
# entities may be an immutable tuple
e = Point(e)
# convert to exact Rationals
d = {}
for f in e.atoms(Float):
prec = f._prec if prec is None else min(f._prec, prec)
d.setdefault(f, nsimplify(f, rational=True))
entities[i] = e.xreplace(d)
if not pairwise:
# find the intersection common to all objects
res = entities[0].intersection(entities[1])
for entity in entities[2:]:
newres = []
for x in res:
newres.extend(x.intersection(entity))
res = newres
else:
# find all pairwise intersections
ans = []
for j in range(len(entities)):
for k in range(j + 1, len(entities)):
ans.extend(intersection(entities[j], entities[k]))
res = list(ordered(set(ans)))
# convert back to Floats
if prec is not None:
p = prec_to_dps(prec)
res = [i.n(p) for i in res]
return res
PK ]ZZZ��Ƌ sympy/holonomic/__init__.pyr"""
The :py:mod:`~sympy.holonomic` module is intended to deal with holonomic functions along
with various operations on them like addition, multiplication, composition,
integration and differentiation. The module also implements various kinds of
conversions such as converting holonomic functions to a different form and the
other way around.
"""
from .holonomic import (DifferentialOperator, HolonomicFunction, DifferentialOperators,
from_hyper, from_meijerg, expr_to_holonomic)
from .recurrence import RecurrenceOperators, RecurrenceOperator, HolonomicSequence
__all__ = [
'DifferentialOperator', 'HolonomicFunction', 'DifferentialOperators',
'from_hyper', 'from_meijerg', 'expr_to_holonomic',
'RecurrenceOperators', 'RecurrenceOperator', 'HolonomicSequence',
]
PK ]ZZZ�M ai ai sympy/holonomic/holonomic.py"""
This module implements Holonomic Functions and
various operations on them.
"""
from sympy.core import Add, Mul, Pow
from sympy.core.numbers import (NaN, Infinity, NegativeInfinity, Float, I, pi,
equal_valued, int_valued)
from sympy.core.singleton import S
from sympy.core.sorting import ordered
from sympy.core.symbol import Dummy, Symbol
from sympy.core.sympify import sympify
from sympy.functions.combinatorial.factorials import binomial, factorial, rf
from sympy.functions.elementary.exponential import exp_polar, exp, log
from sympy.functions.elementary.hyperbolic import (cosh, sinh)
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.elementary.trigonometric import (cos, sin, sinc)
from sympy.functions.special.error_functions import (Ci, Shi, Si, erf, erfc, erfi)
from sympy.functions.special.gamma_functions import gamma
from sympy.functions.special.hyper import hyper, meijerg
from sympy.integrals import meijerint
from sympy.matrices import Matrix
from sympy.polys.rings import PolyElement
from sympy.polys.fields import FracElement
from sympy.polys.domains import QQ, RR
from sympy.polys.polyclasses import DMF
from sympy.polys.polyroots import roots
from sympy.polys.polytools import Poly
from sympy.polys.matrices import DomainMatrix
from sympy.printing import sstr
from sympy.series.limits import limit
from sympy.series.order import Order
from sympy.simplify.hyperexpand import hyperexpand
from sympy.simplify.simplify import nsimplify
from sympy.solvers.solvers import solve
from .recurrence import HolonomicSequence, RecurrenceOperator, RecurrenceOperators
from .holonomicerrors import (NotPowerSeriesError, NotHyperSeriesError,
SingularityError, NotHolonomicError)
def _find_nonzero_solution(r, homosys):
ones = lambda shape: DomainMatrix.ones(shape, r.domain)
particular, nullspace = r._solve(homosys)
nullity = nullspace.shape[0]
nullpart = ones((1, nullity)) * nullspace
sol = (particular + nullpart).transpose()
return sol
def DifferentialOperators(base, generator):
r"""
This function is used to create annihilators using ``Dx``.
Explanation
===========
Returns an Algebra of Differential Operators also called Weyl Algebra
and the operator for differentiation i.e. the ``Dx`` operator.
Parameters
==========
base:
Base polynomial ring for the algebra.
The base polynomial ring is the ring of polynomials in :math:`x` that
will appear as coefficients in the operators.
generator:
Generator of the algebra which can
be either a noncommutative ``Symbol`` or a string. e.g. "Dx" or "D".
Examples
========
>>> from sympy import ZZ
>>> from sympy.abc import x
>>> from sympy.holonomic.holonomic import DifferentialOperators
>>> R, Dx = DifferentialOperators(ZZ.old_poly_ring(x), 'Dx')
>>> R
Univariate Differential Operator Algebra in intermediate Dx over the base ring ZZ[x]
>>> Dx*x
(1) + (x)*Dx
"""
ring = DifferentialOperatorAlgebra(base, generator)
return (ring, ring.derivative_operator)
class DifferentialOperatorAlgebra:
r"""
An Ore Algebra is a set of noncommutative polynomials in the
intermediate ``Dx`` and coefficients in a base polynomial ring :math:`A`.
It follows the commutation rule:
.. math ::
Dxa = \sigma(a)Dx + \delta(a)
for :math:`a \subset A`.
Where :math:`\sigma: A \Rightarrow A` is an endomorphism and :math:`\delta: A \rightarrow A`
is a skew-derivation i.e. :math:`\delta(ab) = \delta(a) b + \sigma(a) \delta(b)`.
If one takes the sigma as identity map and delta as the standard derivation
then it becomes the algebra of Differential Operators also called
a Weyl Algebra i.e. an algebra whose elements are Differential Operators.
This class represents a Weyl Algebra and serves as the parent ring for
Differential Operators.
Examples
========
>>> from sympy import ZZ
>>> from sympy import symbols
>>> from sympy.holonomic.holonomic import DifferentialOperators
>>> x = symbols('x')
>>> R, Dx = DifferentialOperators(ZZ.old_poly_ring(x), 'Dx')
>>> R
Univariate Differential Operator Algebra in intermediate Dx over the base ring
ZZ[x]
See Also
========
DifferentialOperator
"""
def __init__(self, base, generator):
# the base polynomial ring for the algebra
self.base = base
# the operator representing differentiation i.e. `Dx`
self.derivative_operator = DifferentialOperator(
[base.zero, base.one], self)
if generator is None:
self.gen_symbol = Symbol('Dx', commutative=False)
else:
if isinstance(generator, str):
self.gen_symbol = Symbol(generator, commutative=False)
elif isinstance(generator, Symbol):
self.gen_symbol = generator
def __str__(self):
string = 'Univariate Differential Operator Algebra in intermediate '\
+ sstr(self.gen_symbol) + ' over the base ring ' + \
(self.base).__str__()
return string
__repr__ = __str__
def __eq__(self, other):
return self.base == other.base and \
self.gen_symbol == other.gen_symbol
class DifferentialOperator:
"""
Differential Operators are elements of Weyl Algebra. The Operators
are defined by a list of polynomials in the base ring and the
parent ring of the Operator i.e. the algebra it belongs to.
Explanation
===========
Takes a list of polynomials for each power of ``Dx`` and the
parent ring which must be an instance of DifferentialOperatorAlgebra.
A Differential Operator can be created easily using
the operator ``Dx``. See examples below.
Examples
========
>>> from sympy.holonomic.holonomic import DifferentialOperator, DifferentialOperators
>>> from sympy import ZZ
>>> from sympy import symbols
>>> x = symbols('x')
>>> R, Dx = DifferentialOperators(ZZ.old_poly_ring(x),'Dx')
>>> DifferentialOperator([0, 1, x**2], R)
(1)*Dx + (x**2)*Dx**2
>>> (x*Dx*x + 1 - Dx**2)**2
(2*x**2 + 2*x + 1) + (4*x**3 + 2*x**2 - 4)*Dx + (x**4 - 6*x - 2)*Dx**2 + (-2*x**2)*Dx**3 + (1)*Dx**4
See Also
========
DifferentialOperatorAlgebra
"""
_op_priority = 20
def __init__(self, list_of_poly, parent):
"""
Parameters
==========
list_of_poly:
List of polynomials belonging to the base ring of the algebra.
parent:
Parent algebra of the operator.
"""
# the parent ring for this operator
# must be an DifferentialOperatorAlgebra object
self.parent = parent
base = self.parent.base
self.x = base.gens[0] if isinstance(base.gens[0], Symbol) else base.gens[0][0]
# sequence of polynomials in x for each power of Dx
# the list should not have trailing zeroes
# represents the operator
# convert the expressions into ring elements using from_sympy
for i, j in enumerate(list_of_poly):
if not isinstance(j, base.dtype):
list_of_poly[i] = base.from_sympy(sympify(j))
else:
list_of_poly[i] = base.from_sympy(base.to_sympy(j))
self.listofpoly = list_of_poly
# highest power of `Dx`
self.order = len(self.listofpoly) - 1
def __mul__(self, other):
"""
Multiplies two DifferentialOperator and returns another
DifferentialOperator instance using the commutation rule
Dx*a = a*Dx + a'
"""
listofself = self.listofpoly
if isinstance(other, DifferentialOperator):
listofother = other.listofpoly
elif isinstance(other, self.parent.base.dtype):
listofother = [other]
else:
listofother = [self.parent.base.from_sympy(sympify(other))]
# multiplies a polynomial `b` with a list of polynomials
def _mul_dmp_diffop(b, listofother):
if isinstance(listofother, list):
return [i * b for i in listofother]
return [b * listofother]
sol = _mul_dmp_diffop(listofself[0], listofother)
# compute Dx^i * b
def _mul_Dxi_b(b):
sol1 = [self.parent.base.zero]
sol2 = []
if isinstance(b, list):
for i in b:
sol1.append(i)
sol2.append(i.diff())
else:
sol1.append(self.parent.base.from_sympy(b))
sol2.append(self.parent.base.from_sympy(b).diff())
return _add_lists(sol1, sol2)
for i in range(1, len(listofself)):
# find Dx^i * b in ith iteration
listofother = _mul_Dxi_b(listofother)
# solution = solution + listofself[i] * (Dx^i * b)
sol = _add_lists(sol, _mul_dmp_diffop(listofself[i], listofother))
return DifferentialOperator(sol, self.parent)
def __rmul__(self, other):
if not isinstance(other, DifferentialOperator):
if not isinstance(other, self.parent.base.dtype):
other = (self.parent.base).from_sympy(sympify(other))
sol = [other * j for j in self.listofpoly]
return DifferentialOperator(sol, self.parent)
def __add__(self, other):
if isinstance(other, DifferentialOperator):
sol = _add_lists(self.listofpoly, other.listofpoly)
return DifferentialOperator(sol, self.parent)
list_self = self.listofpoly
if not isinstance(other, self.parent.base.dtype):
list_other = [((self.parent).base).from_sympy(sympify(other))]
else:
list_other = [other]
sol = [list_self[0] + list_other[0]] + list_self[1:]
return DifferentialOperator(sol, self.parent)
__radd__ = __add__
def __sub__(self, other):
return self + (-1) * other
def __rsub__(self, other):
return (-1) * self + other
def __neg__(self):
return -1 * self
def __truediv__(self, other):
return self * (S.One / other)
def __pow__(self, n):
if n == 1:
return self
result = DifferentialOperator([self.parent.base.one], self.parent)
if n == 0:
return result
# if self is `Dx`
if self.listofpoly == self.parent.derivative_operator.listofpoly:
sol = [self.parent.base.zero]*n + [self.parent.base.one]
return DifferentialOperator(sol, self.parent)
x = self
while True:
if n % 2:
result *= x
n >>= 1
if not n:
break
x *= x
return result
def __str__(self):
listofpoly = self.listofpoly
print_str = ''
for i, j in enumerate(listofpoly):
if j == self.parent.base.zero:
continue
j = self.parent.base.to_sympy(j)
if i == 0:
print_str += '(' + sstr(j) + ')'
continue
if print_str:
print_str += ' + '
if i == 1:
print_str += '(' + sstr(j) + ')*%s' %(self.parent.gen_symbol)
continue
print_str += '(' + sstr(j) + ')' + '*%s**' %(self.parent.gen_symbol) + sstr(i)
return print_str
__repr__ = __str__
def __eq__(self, other):
if isinstance(other, DifferentialOperator):
return self.listofpoly == other.listofpoly and \
self.parent == other.parent
return self.listofpoly[0] == other and \
all(i is self.parent.base.zero for i in self.listofpoly[1:])
def is_singular(self, x0):
"""
Checks if the differential equation is singular at x0.
"""
base = self.parent.base
return x0 in roots(base.to_sympy(self.listofpoly[-1]), self.x)
class HolonomicFunction:
r"""
A Holonomic Function is a solution to a linear homogeneous ordinary
differential equation with polynomial coefficients. This differential
equation can also be represented by an annihilator i.e. a Differential
Operator ``L`` such that :math:`L.f = 0`. For uniqueness of these functions,
initial conditions can also be provided along with the annihilator.
Explanation
===========
Holonomic functions have closure properties and thus forms a ring.
Given two Holonomic Functions f and g, their sum, product,
integral and derivative is also a Holonomic Function.
For ordinary points initial condition should be a vector of values of
the derivatives i.e. :math:`[y(x_0), y'(x_0), y''(x_0) ... ]`.
For regular singular points initial conditions can also be provided in this
format:
:math:`{s0: [C_0, C_1, ...], s1: [C^1_0, C^1_1, ...], ...}`
where s0, s1, ... are the roots of indicial equation and vectors
:math:`[C_0, C_1, ...], [C^0_0, C^0_1, ...], ...` are the corresponding initial
terms of the associated power series. See Examples below.
Examples
========
>>> from sympy.holonomic.holonomic import HolonomicFunction, DifferentialOperators
>>> from sympy import QQ
>>> from sympy import symbols, S
>>> x = symbols('x')
>>> R, Dx = DifferentialOperators(QQ.old_poly_ring(x),'Dx')
>>> p = HolonomicFunction(Dx - 1, x, 0, [1]) # e^x
>>> q = HolonomicFunction(Dx**2 + 1, x, 0, [0, 1]) # sin(x)
>>> p + q # annihilator of e^x + sin(x)
HolonomicFunction((-1) + (1)*Dx + (-1)*Dx**2 + (1)*Dx**3, x, 0, [1, 2, 1])
>>> p * q # annihilator of e^x * sin(x)
HolonomicFunction((2) + (-2)*Dx + (1)*Dx**2, x, 0, [0, 1])
An example of initial conditions for regular singular points,
the indicial equation has only one root `1/2`.
>>> HolonomicFunction(-S(1)/2 + x*Dx, x, 0, {S(1)/2: [1]})
HolonomicFunction((-1/2) + (x)*Dx, x, 0, {1/2: [1]})
>>> HolonomicFunction(-S(1)/2 + x*Dx, x, 0, {S(1)/2: [1]}).to_expr()
sqrt(x)
To plot a Holonomic Function, one can use `.evalf()` for numerical
computation. Here's an example on `sin(x)**2/x` using numpy and matplotlib.
>>> import sympy.holonomic # doctest: +SKIP
>>> from sympy import var, sin # doctest: +SKIP
>>> import matplotlib.pyplot as plt # doctest: +SKIP
>>> import numpy as np # doctest: +SKIP
>>> var("x") # doctest: +SKIP
>>> r = np.linspace(1, 5, 100) # doctest: +SKIP
>>> y = sympy.holonomic.expr_to_holonomic(sin(x)**2/x, x0=1).evalf(r) # doctest: +SKIP
>>> plt.plot(r, y, label="holonomic function") # doctest: +SKIP
>>> plt.show() # doctest: +SKIP
"""
_op_priority = 20
def __init__(self, annihilator, x, x0=0, y0=None):
"""
Parameters
==========
annihilator:
Annihilator of the Holonomic Function, represented by a
`DifferentialOperator` object.
x:
Variable of the function.
x0:
The point at which initial conditions are stored.
Generally an integer.
y0:
The initial condition. The proper format for the initial condition
is described in class docstring. To make the function unique,
length of the vector `y0` should be equal to or greater than the
order of differential equation.
"""
# initial condition
self.y0 = y0
# the point for initial conditions, default is zero.
self.x0 = x0
# differential operator L such that L.f = 0
self.annihilator = annihilator
self.x = x
def __str__(self):
if self._have_init_cond():
str_sol = 'HolonomicFunction(%s, %s, %s, %s)' % (str(self.annihilator),\
sstr(self.x), sstr(self.x0), sstr(self.y0))
else:
str_sol = 'HolonomicFunction(%s, %s)' % (str(self.annihilator),\
sstr(self.x))
return str_sol
__repr__ = __str__
def unify(self, other):
"""
Unifies the base polynomial ring of a given two Holonomic
Functions.
"""
R1 = self.annihilator.parent.base
R2 = other.annihilator.parent.base
dom1 = R1.dom
dom2 = R2.dom
if R1 == R2:
return (self, other)
R = (dom1.unify(dom2)).old_poly_ring(self.x)
newparent, _ = DifferentialOperators(R, str(self.annihilator.parent.gen_symbol))
sol1 = [R1.to_sympy(i) for i in self.annihilator.listofpoly]
sol2 = [R2.to_sympy(i) for i in other.annihilator.listofpoly]
sol1 = DifferentialOperator(sol1, newparent)
sol2 = DifferentialOperator(sol2, newparent)
sol1 = HolonomicFunction(sol1, self.x, self.x0, self.y0)
sol2 = HolonomicFunction(sol2, other.x, other.x0, other.y0)
return (sol1, sol2)
def is_singularics(self):
"""
Returns True if the function have singular initial condition
in the dictionary format.
Returns False if the function have ordinary initial condition
in the list format.
Returns None for all other cases.
"""
if isinstance(self.y0, dict):
return True
elif isinstance(self.y0, list):
return False
def _have_init_cond(self):
"""
Checks if the function have initial condition.
"""
return bool(self.y0)
def _singularics_to_ord(self):
"""
Converts a singular initial condition to ordinary if possible.
"""
a = list(self.y0)[0]
b = self.y0[a]
if len(self.y0) == 1 and a == int(a) and a > 0:
a = int(a)
y0 = [S.Zero] * a
y0 += [j * factorial(a + i) for i, j in enumerate(b)]
return HolonomicFunction(self.annihilator, self.x, self.x0, y0)
def __add__(self, other):
# if the ground domains are different
if self.annihilator.parent.base != other.annihilator.parent.base:
a, b = self.unify(other)
return a + b
deg1 = self.annihilator.order
deg2 = other.annihilator.order
dim = max(deg1, deg2)
R = self.annihilator.parent.base
K = R.get_field()
rowsself = [self.annihilator]
rowsother = [other.annihilator]
gen = self.annihilator.parent.derivative_operator
# constructing annihilators up to order dim
for i in range(dim - deg1):
diff1 = (gen * rowsself[-1])
rowsself.append(diff1)
for i in range(dim - deg2):
diff2 = (gen * rowsother[-1])
rowsother.append(diff2)
row = rowsself + rowsother
# constructing the matrix of the ansatz
r = []
for expr in row:
p = []
for i in range(dim + 1):
if i >= len(expr.listofpoly):
p.append(K.zero)
else:
p.append(K.new(expr.listofpoly[i].to_list()))
r.append(p)
# solving the linear system using gauss jordan solver
r = DomainMatrix(r, (len(row), dim+1), K).transpose()
homosys = DomainMatrix.zeros((dim+1, 1), K)
sol = _find_nonzero_solution(r, homosys)
# if a solution is not obtained then increasing the order by 1 in each
# iteration
while sol.is_zero_matrix:
dim += 1
diff1 = (gen * rowsself[-1])
rowsself.append(diff1)
diff2 = (gen * rowsother[-1])
rowsother.append(diff2)
row = rowsself + rowsother
r = []
for expr in row:
p = []
for i in range(dim + 1):
if i >= len(expr.listofpoly):
p.append(K.zero)
else:
p.append(K.new(expr.listofpoly[i].to_list()))
r.append(p)
# solving the linear system using gauss jordan solver
r = DomainMatrix(r, (len(row), dim+1), K).transpose()
homosys = DomainMatrix.zeros((dim+1, 1), K)
sol = _find_nonzero_solution(r, homosys)
# taking only the coefficients needed to multiply with `self`
# can be also be done the other way by taking R.H.S and multiplying with
# `other`
sol = sol.flat()[:dim + 1 - deg1]
sol1 = _normalize(sol, self.annihilator.parent)
# annihilator of the solution
sol = sol1 * (self.annihilator)
sol = _normalize(sol.listofpoly, self.annihilator.parent, negative=False)
if not (self._have_init_cond() and other._have_init_cond()):
return HolonomicFunction(sol, self.x)
# both the functions have ordinary initial conditions
if self.is_singularics() == False and other.is_singularics() == False:
# directly add the corresponding value
if self.x0 == other.x0:
# try to extended the initial conditions
# using the annihilator
y1 = _extend_y0(self, sol.order)
y2 = _extend_y0(other, sol.order)
y0 = [a + b for a, b in zip(y1, y2)]
return HolonomicFunction(sol, self.x, self.x0, y0)
# change the initial conditions to a same point
selfat0 = self.annihilator.is_singular(0)
otherat0 = other.annihilator.is_singular(0)
if self.x0 == 0 and not selfat0 and not otherat0:
return self + other.change_ics(0)
if other.x0 == 0 and not selfat0 and not otherat0:
return self.change_ics(0) + other
selfatx0 = self.annihilator.is_singular(self.x0)
otheratx0 = other.annihilator.is_singular(self.x0)
if not selfatx0 and not otheratx0:
return self + other.change_ics(self.x0)
return self.change_ics(other.x0) + other
if self.x0 != other.x0:
return HolonomicFunction(sol, self.x)
# if the functions have singular_ics
y1 = None
y2 = None
if self.is_singularics() == False and other.is_singularics() == True:
# convert the ordinary initial condition to singular.
_y0 = [j / factorial(i) for i, j in enumerate(self.y0)]
y1 = {S.Zero: _y0}
y2 = other.y0
elif self.is_singularics() == True and other.is_singularics() == False:
_y0 = [j / factorial(i) for i, j in enumerate(other.y0)]
y1 = self.y0
y2 = {S.Zero: _y0}
elif self.is_singularics() == True and other.is_singularics() == True:
y1 = self.y0
y2 = other.y0
# computing singular initial condition for the result
# taking union of the series terms of both functions
y0 = {}
for i in y1:
# add corresponding initial terms if the power
# on `x` is same
if i in y2:
y0[i] = [a + b for a, b in zip(y1[i], y2[i])]
else:
y0[i] = y1[i]
for i in y2:
if i not in y1:
y0[i] = y2[i]
return HolonomicFunction(sol, self.x, self.x0, y0)
def integrate(self, limits, initcond=False):
"""
Integrates the given holonomic function.
Examples
========
>>> from sympy.holonomic.holonomic import HolonomicFunction, DifferentialOperators
>>> from sympy import QQ
>>> from sympy import symbols
>>> x = symbols('x')
>>> R, Dx = DifferentialOperators(QQ.old_poly_ring(x),'Dx')
>>> HolonomicFunction(Dx - 1, x, 0, [1]).integrate((x, 0, x)) # e^x - 1
HolonomicFunction((-1)*Dx + (1)*Dx**2, x, 0, [0, 1])
>>> HolonomicFunction(Dx**2 + 1, x, 0, [1, 0]).integrate((x, 0, x))
HolonomicFunction((1)*Dx + (1)*Dx**3, x, 0, [0, 1, 0])
"""
# to get the annihilator, just multiply by Dx from right
D = self.annihilator.parent.derivative_operator
# if the function have initial conditions of the series format
if self.is_singularics() == True:
r = self._singularics_to_ord()
if r:
return r.integrate(limits, initcond=initcond)
# computing singular initial condition for the function
# produced after integration.
y0 = {}
for i in self.y0:
c = self.y0[i]
c2 = []
for j, cj in enumerate(c):
if cj == 0:
c2.append(S.Zero)
# if power on `x` is -1, the integration becomes log(x)
# TODO: Implement this case
elif i + j + 1 == 0:
raise NotImplementedError("logarithmic terms in the series are not supported")
else:
c2.append(cj / S(i + j + 1))
y0[i + 1] = c2
if hasattr(limits, "__iter__"):
raise NotImplementedError("Definite integration for singular initial conditions")
return HolonomicFunction(self.annihilator * D, self.x, self.x0, y0)
# if no initial conditions are available for the function
if not self._have_init_cond():
if initcond:
return HolonomicFunction(self.annihilator * D, self.x, self.x0, [S.Zero])
return HolonomicFunction(self.annihilator * D, self.x)
# definite integral
# initial conditions for the answer will be stored at point `a`,
# where `a` is the lower limit of the integrand
if hasattr(limits, "__iter__"):
if len(limits) == 3 and limits[0] == self.x:
x0 = self.x0
a = limits[1]
b = limits[2]
definite = True
else:
definite = False
y0 = [S.Zero]
y0 += self.y0
indefinite_integral = HolonomicFunction(self.annihilator * D, self.x, self.x0, y0)
if not definite:
return indefinite_integral
# use evalf to get the values at `a`
if x0 != a:
try:
indefinite_expr = indefinite_integral.to_expr()
except (NotHyperSeriesError, NotPowerSeriesError):
indefinite_expr = None
if indefinite_expr:
lower = indefinite_expr.subs(self.x, a)
if isinstance(lower, NaN):
lower = indefinite_expr.limit(self.x, a)
else:
lower = indefinite_integral.evalf(a)
if b == self.x:
y0[0] = y0[0] - lower
return HolonomicFunction(self.annihilator * D, self.x, x0, y0)
elif S(b).is_Number:
if indefinite_expr:
upper = indefinite_expr.subs(self.x, b)
if isinstance(upper, NaN):
upper = indefinite_expr.limit(self.x, b)
else:
upper = indefinite_integral.evalf(b)
return upper - lower
# if the upper limit is `x`, the answer will be a function
if b == self.x:
return HolonomicFunction(self.annihilator * D, self.x, a, y0)
# if the upper limits is a Number, a numerical value will be returned
elif S(b).is_Number:
try:
s = HolonomicFunction(self.annihilator * D, self.x, a,\
y0).to_expr()
indefinite = s.subs(self.x, b)
if not isinstance(indefinite, NaN):
return indefinite
else:
return s.limit(self.x, b)
except (NotHyperSeriesError, NotPowerSeriesError):
return HolonomicFunction(self.annihilator * D, self.x, a, y0).evalf(b)
return HolonomicFunction(self.annihilator * D, self.x)
def diff(self, *args, **kwargs):
r"""
Differentiation of the given Holonomic function.
Examples
========
>>> from sympy.holonomic.holonomic import HolonomicFunction, DifferentialOperators
>>> from sympy import ZZ
>>> from sympy import symbols
>>> x = symbols('x')
>>> R, Dx = DifferentialOperators(ZZ.old_poly_ring(x),'Dx')
>>> HolonomicFunction(Dx**2 + 1, x, 0, [0, 1]).diff().to_expr()
cos(x)
>>> HolonomicFunction(Dx - 2, x, 0, [1]).diff().to_expr()
2*exp(2*x)
See Also
========
integrate
"""
kwargs.setdefault('evaluate', True)
if args:
if args[0] != self.x:
return S.Zero
elif len(args) == 2:
sol = self
for i in range(args[1]):
sol = sol.diff(args[0])
return sol
ann = self.annihilator
# if the function is constant.
if ann.listofpoly[0] == ann.parent.base.zero and ann.order == 1:
return S.Zero
# if the coefficient of y in the differential equation is zero.
# a shifting is done to compute the answer in this case.
elif ann.listofpoly[0] == ann.parent.base.zero:
sol = DifferentialOperator(ann.listofpoly[1:], ann.parent)
if self._have_init_cond():
# if ordinary initial condition
if self.is_singularics() == False:
return HolonomicFunction(sol, self.x, self.x0, self.y0[1:])
# TODO: support for singular initial condition
return HolonomicFunction(sol, self.x)
else:
return HolonomicFunction(sol, self.x)
# the general algorithm
R = ann.parent.base
K = R.get_field()
seq_dmf = [K.new(i.to_list()) for i in ann.listofpoly]
# -y = a1*y'/a0 + a2*y''/a0 ... + an*y^n/a0
rhs = [i / seq_dmf[0] for i in seq_dmf[1:]]
rhs.insert(0, K.zero)
# differentiate both lhs and rhs
sol = _derivate_diff_eq(rhs, K)
# add the term y' in lhs to rhs
sol = _add_lists(sol, [K.zero, K.one])
sol = _normalize(sol[1:], self.annihilator.parent, negative=False)
if not self._have_init_cond() or self.is_singularics() == True:
return HolonomicFunction(sol, self.x)
y0 = _extend_y0(self, sol.order + 1)[1:]
return HolonomicFunction(sol, self.x, self.x0, y0)
def __eq__(self, other):
if self.annihilator != other.annihilator or self.x != other.x:
return False
if self._have_init_cond() and other._have_init_cond():
return self.x0 == other.x0 and self.y0 == other.y0
return True
def __mul__(self, other):
ann_self = self.annihilator
if not isinstance(other, HolonomicFunction):
other = sympify(other)
if other.has(self.x):
raise NotImplementedError(" Can't multiply a HolonomicFunction and expressions/functions.")
if not self._have_init_cond():
return self
y0 = _extend_y0(self, ann_self.order)
y1 = [(Poly.new(j, self.x) * other).rep for j in y0]
return HolonomicFunction(ann_self, self.x, self.x0, y1)
if self.annihilator.parent.base != other.annihilator.parent.base:
a, b = self.unify(other)
return a * b
ann_other = other.annihilator
a = ann_self.order
b = ann_other.order
R = ann_self.parent.base
K = R.get_field()
list_self = [K.new(j.to_list()) for j in ann_self.listofpoly]
list_other = [K.new(j.to_list()) for j in ann_other.listofpoly]
# will be used to reduce the degree
self_red = [-list_self[i] / list_self[a] for i in range(a)]
other_red = [-list_other[i] / list_other[b] for i in range(b)]
# coeff_mull[i][j] is the coefficient of Dx^i(f).Dx^j(g)
coeff_mul = [[K.zero for i in range(b + 1)] for j in range(a + 1)]
coeff_mul[0][0] = K.one
# making the ansatz
lin_sys_elements = [[coeff_mul[i][j] for i in range(a) for j in range(b)]]
lin_sys = DomainMatrix(lin_sys_elements, (1, a*b), K).transpose()
homo_sys = DomainMatrix.zeros((a*b, 1), K)
sol = _find_nonzero_solution(lin_sys, homo_sys)
# until a non trivial solution is found
while sol.is_zero_matrix:
# updating the coefficients Dx^i(f).Dx^j(g) for next degree
for i in range(a - 1, -1, -1):
for j in range(b - 1, -1, -1):
coeff_mul[i][j + 1] += coeff_mul[i][j]
coeff_mul[i + 1][j] += coeff_mul[i][j]
if isinstance(coeff_mul[i][j], K.dtype):
coeff_mul[i][j] = DMFdiff(coeff_mul[i][j], K)
else:
coeff_mul[i][j] = coeff_mul[i][j].diff(self.x)
# reduce the terms to lower power using annihilators of f, g
for i in range(a + 1):
if coeff_mul[i][b].is_zero:
continue
for j in range(b):
coeff_mul[i][j] += other_red[j] * coeff_mul[i][b]
coeff_mul[i][b] = K.zero
# not d2 + 1, as that is already covered in previous loop
for j in range(b):
if coeff_mul[a][j] == 0:
continue
for i in range(a):
coeff_mul[i][j] += self_red[i] * coeff_mul[a][j]
coeff_mul[a][j] = K.zero
lin_sys_elements.append([coeff_mul[i][j] for i in range(a) for j in range(b)])
lin_sys = DomainMatrix(lin_sys_elements, (len(lin_sys_elements), a*b), K).transpose()
sol = _find_nonzero_solution(lin_sys, homo_sys)
sol_ann = _normalize(sol.flat(), self.annihilator.parent, negative=False)
if not (self._have_init_cond() and other._have_init_cond()):
return HolonomicFunction(sol_ann, self.x)
if self.is_singularics() == False and other.is_singularics() == False:
# if both the conditions are at same point
if self.x0 == other.x0:
# try to find more initial conditions
y0_self = _extend_y0(self, sol_ann.order)
y0_other = _extend_y0(other, sol_ann.order)
# h(x0) = f(x0) * g(x0)
y0 = [y0_self[0] * y0_other[0]]
# coefficient of Dx^j(f)*Dx^i(g) in Dx^i(fg)
for i in range(1, min(len(y0_self), len(y0_other))):
coeff = [[0 for i in range(i + 1)] for j in range(i + 1)]
for j in range(i + 1):
for k in range(i + 1):
if j + k == i:
coeff[j][k] = binomial(i, j)
sol = 0
for j in range(i + 1):
for k in range(i + 1):
sol += coeff[j][k]* y0_self[j] * y0_other[k]
y0.append(sol)
return HolonomicFunction(sol_ann, self.x, self.x0, y0)
# if the points are different, consider one
selfat0 = self.annihilator.is_singular(0)
otherat0 = other.annihilator.is_singular(0)
if self.x0 == 0 and not selfat0 and not otherat0:
return self * other.change_ics(0)
if other.x0 == 0 and not selfat0 and not otherat0:
return self.change_ics(0) * other
selfatx0 = self.annihilator.is_singular(self.x0)
otheratx0 = other.annihilator.is_singular(self.x0)
if not selfatx0 and not otheratx0:
return self * other.change_ics(self.x0)
return self.change_ics(other.x0) * other
if self.x0 != other.x0:
return HolonomicFunction(sol_ann, self.x)
# if the functions have singular_ics
y1 = None
y2 = None
if self.is_singularics() == False and other.is_singularics() == True:
_y0 = [j / factorial(i) for i, j in enumerate(self.y0)]
y1 = {S.Zero: _y0}
y2 = other.y0
elif self.is_singularics() == True and other.is_singularics() == False:
_y0 = [j / factorial(i) for i, j in enumerate(other.y0)]
y1 = self.y0
y2 = {S.Zero: _y0}
elif self.is_singularics() == True and other.is_singularics() == True:
y1 = self.y0
y2 = other.y0
y0 = {}
# multiply every possible pair of the series terms
for i in y1:
for j in y2:
k = min(len(y1[i]), len(y2[j]))
c = [sum((y1[i][b] * y2[j][a - b] for b in range(a + 1)),
start=S.Zero) for a in range(k)]
if not i + j in y0:
y0[i + j] = c
else:
y0[i + j] = [a + b for a, b in zip(c, y0[i + j])]
return HolonomicFunction(sol_ann, self.x, self.x0, y0)
__rmul__ = __mul__
def __sub__(self, other):
return self + other * -1
def __rsub__(self, other):
return self * -1 + other
def __neg__(self):
return -1 * self
def __truediv__(self, other):
return self * (S.One / other)
def __pow__(self, n):
if self.annihilator.order <= 1:
ann = self.annihilator
parent = ann.parent
if self.y0 is None:
y0 = None
else:
y0 = [list(self.y0)[0] ** n]
p0 = ann.listofpoly[0]
p1 = ann.listofpoly[1]
p0 = (Poly.new(p0, self.x) * n).rep
sol = [parent.base.to_sympy(i) for i in [p0, p1]]
dd = DifferentialOperator(sol, parent)
return HolonomicFunction(dd, self.x, self.x0, y0)
if n < 0:
raise NotHolonomicError("Negative Power on a Holonomic Function")
Dx = self.annihilator.parent.derivative_operator
result = HolonomicFunction(Dx, self.x, S.Zero, [S.One])
if n == 0:
return result
x = self
while True:
if n % 2:
result *= x
n >>= 1
if not n:
break
x *= x
return result
def degree(self):
"""
Returns the highest power of `x` in the annihilator.
"""
return max(i.degree() for i in self.annihilator.listofpoly)
def composition(self, expr, *args, **kwargs):
"""
Returns function after composition of a holonomic
function with an algebraic function. The method cannot compute
initial conditions for the result by itself, so they can be also be
provided.
Examples
========
>>> from sympy.holonomic.holonomic import HolonomicFunction, DifferentialOperators
>>> from sympy import QQ
>>> from sympy import symbols
>>> x = symbols('x')
>>> R, Dx = DifferentialOperators(QQ.old_poly_ring(x),'Dx')
>>> HolonomicFunction(Dx - 1, x).composition(x**2, 0, [1]) # e^(x**2)
HolonomicFunction((-2*x) + (1)*Dx, x, 0, [1])
>>> HolonomicFunction(Dx**2 + 1, x).composition(x**2 - 1, 1, [1, 0])
HolonomicFunction((4*x**3) + (-1)*Dx + (x)*Dx**2, x, 1, [1, 0])
See Also
========
from_hyper
"""
R = self.annihilator.parent
a = self.annihilator.order
diff = expr.diff(self.x)
listofpoly = self.annihilator.listofpoly
for i, j in enumerate(listofpoly):
if isinstance(j, self.annihilator.parent.base.dtype):
listofpoly[i] = self.annihilator.parent.base.to_sympy(j)
r = listofpoly[a].subs({self.x:expr})
subs = [-listofpoly[i].subs({self.x:expr}) / r for i in range (a)]
coeffs = [S.Zero for i in range(a)] # coeffs[i] == coeff of (D^i f)(a) in D^k (f(a))
coeffs[0] = S.One
system = [coeffs]
homogeneous = Matrix([[S.Zero for i in range(a)]]).transpose()
while True:
coeffs_next = [p.diff(self.x) for p in coeffs]
for i in range(a - 1):
coeffs_next[i + 1] += (coeffs[i] * diff)
for i in range(a):
coeffs_next[i] += (coeffs[-1] * subs[i] * diff)
coeffs = coeffs_next
# check for linear relations
system.append(coeffs)
sol, taus = (Matrix(system).transpose()
).gauss_jordan_solve(homogeneous)
if sol.is_zero_matrix is not True:
break
tau = list(taus)[0]
sol = sol.subs(tau, 1)
sol = _normalize(sol[0:], R, negative=False)
# if initial conditions are given for the resulting function
if args:
return HolonomicFunction(sol, self.x, args[0], args[1])
return HolonomicFunction(sol, self.x)
def to_sequence(self, lb=True):
r"""
Finds recurrence relation for the coefficients in the series expansion
of the function about :math:`x_0`, where :math:`x_0` is the point at
which the initial condition is stored.
Explanation
===========
If the point :math:`x_0` is ordinary, solution of the form :math:`[(R, n_0)]`
is returned. Where :math:`R` is the recurrence relation and :math:`n_0` is the
smallest ``n`` for which the recurrence holds true.
If the point :math:`x_0` is regular singular, a list of solutions in
the format :math:`(R, p, n_0)` is returned, i.e. `[(R, p, n_0), ... ]`.
Each tuple in this vector represents a recurrence relation :math:`R`
associated with a root of the indicial equation ``p``. Conditions of
a different format can also be provided in this case, see the
docstring of HolonomicFunction class.
If it's not possible to numerically compute a initial condition,
it is returned as a symbol :math:`C_j`, denoting the coefficient of
:math:`(x - x_0)^j` in the power series about :math:`x_0`.
Examples
========
>>> from sympy.holonomic.holonomic import HolonomicFunction, DifferentialOperators
>>> from sympy import QQ
>>> from sympy import symbols, S
>>> x = symbols('x')
>>> R, Dx = DifferentialOperators(QQ.old_poly_ring(x),'Dx')
>>> HolonomicFunction(Dx - 1, x, 0, [1]).to_sequence()
[(HolonomicSequence((-1) + (n + 1)Sn, n), u(0) = 1, 0)]
>>> HolonomicFunction((1 + x)*Dx**2 + Dx, x, 0, [0, 1]).to_sequence()
[(HolonomicSequence((n**2) + (n**2 + n)Sn, n), u(0) = 0, u(1) = 1, u(2) = -1/2, 2)]
>>> HolonomicFunction(-S(1)/2 + x*Dx, x, 0, {S(1)/2: [1]}).to_sequence()
[(HolonomicSequence((n), n), u(0) = 1, 1/2, 1)]
See Also
========
HolonomicFunction.series
References
==========
.. [1] https://hal.inria.fr/inria-00070025/document
.. [2] https://www3.risc.jku.at/publications/download/risc_2244/DIPLFORM.pdf
"""
if self.x0 != 0:
return self.shift_x(self.x0).to_sequence()
# check whether a power series exists if the point is singular
if self.annihilator.is_singular(self.x0):
return self._frobenius(lb=lb)
dict1 = {}
n = Symbol('n', integer=True)
dom = self.annihilator.parent.base.dom
R, _ = RecurrenceOperators(dom.old_poly_ring(n), 'Sn')
# substituting each term of the form `x^k Dx^j` in the
# annihilator, according to the formula below:
# x^k Dx^j = Sum(rf(n + 1 - k, j) * a(n + j - k) * x^n, (n, k, oo))
# for explanation see [2].
for i, j in enumerate(self.annihilator.listofpoly):
listofdmp = j.all_coeffs()
degree = len(listofdmp) - 1
for k in range(degree + 1):
coeff = listofdmp[degree - k]
if coeff == 0:
continue
if (i - k, k) in dict1:
dict1[(i - k, k)] += (dom.to_sympy(coeff) * rf(n - k + 1, i))
else:
dict1[(i - k, k)] = (dom.to_sympy(coeff) * rf(n - k + 1, i))
sol = []
keylist = [i[0] for i in dict1]
lower = min(keylist)
upper = max(keylist)
degree = self.degree()
# the recurrence relation holds for all values of
# n greater than smallest_n, i.e. n >= smallest_n
smallest_n = lower + degree
dummys = {}
eqs = []
unknowns = []
# an appropriate shift of the recurrence
for j in range(lower, upper + 1):
if j in keylist:
temp = sum((v.subs(n, n - lower)
for k, v in dict1.items() if k[0] == j),
start=S.Zero)
sol.append(temp)
else:
sol.append(S.Zero)
# the recurrence relation
sol = RecurrenceOperator(sol, R)
# computing the initial conditions for recurrence
order = sol.order
all_roots = roots(R.base.to_sympy(sol.listofpoly[-1]), n, filter='Z')
all_roots = all_roots.keys()
if all_roots:
max_root = max(all_roots) + 1
smallest_n = max(max_root, smallest_n)
order += smallest_n
y0 = _extend_y0(self, order)
# u(n) = y^n(0)/factorial(n)
u0 = [j / factorial(i) for i, j in enumerate(y0)]
# if sufficient conditions can't be computed then
# try to use the series method i.e.
# equate the coefficients of x^k in the equation formed by
# substituting the series in differential equation, to zero.
if len(u0) < order:
for i in range(degree):
eq = S.Zero
for j in dict1:
if i + j[0] < 0:
dummys[i + j[0]] = S.Zero
elif i + j[0] < len(u0):
dummys[i + j[0]] = u0[i + j[0]]
elif not i + j[0] in dummys:
dummys[i + j[0]] = Symbol('C_%s' %(i + j[0]))
unknowns.append(dummys[i + j[0]])
if j[1] <= i:
eq += dict1[j].subs(n, i) * dummys[i + j[0]]
eqs.append(eq)
# solve the system of equations formed
soleqs = solve(eqs, *unknowns)
if isinstance(soleqs, dict):
for i in range(len(u0), order):
if i not in dummys:
dummys[i] = Symbol('C_%s' %i)
if dummys[i] in soleqs:
u0.append(soleqs[dummys[i]])
else:
u0.append(dummys[i])
if lb:
return [(HolonomicSequence(sol, u0), smallest_n)]
return [HolonomicSequence(sol, u0)]
for i in range(len(u0), order):
if i not in dummys:
dummys[i] = Symbol('C_%s' %i)
s = False
for j in soleqs:
if dummys[i] in j:
u0.append(j[dummys[i]])
s = True
if not s:
u0.append(dummys[i])
if lb:
return [(HolonomicSequence(sol, u0), smallest_n)]
return [HolonomicSequence(sol, u0)]
def _frobenius(self, lb=True):
# compute the roots of indicial equation
indicialroots = self._indicial()
reals = []
compl = []
for i in ordered(indicialroots.keys()):
if i.is_real:
reals.extend([i] * indicialroots[i])
else:
a, b = i.as_real_imag()
compl.extend([(i, a, b)] * indicialroots[i])
# sort the roots for a fixed ordering of solution
compl.sort(key=lambda x : x[1])
compl.sort(key=lambda x : x[2])
reals.sort()
# grouping the roots, roots differ by an integer are put in the same group.
grp = []
for i in reals:
if len(grp) == 0:
grp.append([i])
continue
for j in grp:
if int_valued(j[0] - i):
j.append(i)
break
else:
grp.append([i])
# True if none of the roots differ by an integer i.e.
# each element in group have only one member
independent = all(len(i) == 1 for i in grp)
allpos = all(i >= 0 for i in reals)
allint = all(int_valued(i) for i in reals)
# if initial conditions are provided
# then use them.
if self.is_singularics() == True:
rootstoconsider = []
for i in ordered(self.y0.keys()):
for j in ordered(indicialroots.keys()):
if equal_valued(j, i):
rootstoconsider.append(i)
elif allpos and allint:
rootstoconsider = [min(reals)]
elif independent:
rootstoconsider = [i[0] for i in grp] + [j[0] for j in compl]
elif not allint:
rootstoconsider = [i for i in reals if not int(i) == i]
elif not allpos:
if not self._have_init_cond() or S(self.y0[0]).is_finite == False:
rootstoconsider = [min(reals)]
else:
posroots = [i for i in reals if i >= 0]
rootstoconsider = [min(posroots)]
n = Symbol('n', integer=True)
dom = self.annihilator.parent.base.dom
R, _ = RecurrenceOperators(dom.old_poly_ring(n), 'Sn')
finalsol = []
char = ord('C')
for p in rootstoconsider:
dict1 = {}
for i, j in enumerate(self.annihilator.listofpoly):
listofdmp = j.all_coeffs()
degree = len(listofdmp) - 1
for k in range(degree + 1):
coeff = listofdmp[degree - k]
if coeff == 0:
continue
if (i - k, k - i) in dict1:
dict1[(i - k, k - i)] += (dom.to_sympy(coeff) * rf(n - k + 1 + p, i))
else:
dict1[(i - k, k - i)] = (dom.to_sympy(coeff) * rf(n - k + 1 + p, i))
sol = []
keylist = [i[0] for i in dict1]
lower = min(keylist)
upper = max(keylist)
degree = max(i[1] for i in dict1)
degree2 = min(i[1] for i in dict1)
smallest_n = lower + degree
dummys = {}
eqs = []
unknowns = []
for j in range(lower, upper + 1):
if j in keylist:
temp = sum((v.subs(n, n - lower)
for k, v in dict1.items() if k[0] == j),
start=S.Zero)
sol.append(temp)
else:
sol.append(S.Zero)
# the recurrence relation
sol = RecurrenceOperator(sol, R)
# computing the initial conditions for recurrence
order = sol.order
all_roots = roots(R.base.to_sympy(sol.listofpoly[-1]), n, filter='Z')
all_roots = all_roots.keys()
if all_roots:
max_root = max(all_roots) + 1
smallest_n = max(max_root, smallest_n)
order += smallest_n
u0 = []
if self.is_singularics() == True:
u0 = self.y0[p]
elif self.is_singularics() == False and p >= 0 and int(p) == p and len(rootstoconsider) == 1:
y0 = _extend_y0(self, order + int(p))
# u(n) = y^n(0)/factorial(n)
if len(y0) > int(p):
u0 = [y0[i] / factorial(i) for i in range(int(p), len(y0))]
if len(u0) < order:
for i in range(degree2, degree):
eq = S.Zero
for j in dict1:
if i + j[0] < 0:
dummys[i + j[0]] = S.Zero
elif i + j[0] < len(u0):
dummys[i + j[0]] = u0[i + j[0]]
elif not i + j[0] in dummys:
letter = chr(char) + '_%s' %(i + j[0])
dummys[i + j[0]] = Symbol(letter)
unknowns.append(dummys[i + j[0]])
if j[1] <= i:
eq += dict1[j].subs(n, i) * dummys[i + j[0]]
eqs.append(eq)
# solve the system of equations formed
soleqs = solve(eqs, *unknowns)
if isinstance(soleqs, dict):
for i in range(len(u0), order):
if i not in dummys:
letter = chr(char) + '_%s' %i
dummys[i] = Symbol(letter)
if dummys[i] in soleqs:
u0.append(soleqs[dummys[i]])
else:
u0.append(dummys[i])
if lb:
finalsol.append((HolonomicSequence(sol, u0), p, smallest_n))
continue
else:
finalsol.append((HolonomicSequence(sol, u0), p))
continue
for i in range(len(u0), order):
if i not in dummys:
letter = chr(char) + '_%s' %i
dummys[i] = Symbol(letter)
s = False
for j in soleqs:
if dummys[i] in j:
u0.append(j[dummys[i]])
s = True
if not s:
u0.append(dummys[i])
if lb:
finalsol.append((HolonomicSequence(sol, u0), p, smallest_n))
else:
finalsol.append((HolonomicSequence(sol, u0), p))
char += 1
return finalsol
def series(self, n=6, coefficient=False, order=True, _recur=None):
r"""
Finds the power series expansion of given holonomic function about :math:`x_0`.
Explanation
===========
A list of series might be returned if :math:`x_0` is a regular point with
multiple roots of the indicial equation.
Examples
========
>>> from sympy.holonomic.holonomic import HolonomicFunction, DifferentialOperators
>>> from sympy import QQ
>>> from sympy import symbols
>>> x = symbols('x')
>>> R, Dx = DifferentialOperators(QQ.old_poly_ring(x),'Dx')
>>> HolonomicFunction(Dx - 1, x, 0, [1]).series() # e^x
1 + x + x**2/2 + x**3/6 + x**4/24 + x**5/120 + O(x**6)
>>> HolonomicFunction(Dx**2 + 1, x, 0, [0, 1]).series(n=8) # sin(x)
x - x**3/6 + x**5/120 - x**7/5040 + O(x**8)
See Also
========
HolonomicFunction.to_sequence
"""
if _recur is None:
recurrence = self.to_sequence()
else:
recurrence = _recur
if isinstance(recurrence, tuple) and len(recurrence) == 2:
recurrence = recurrence[0]
constantpower = 0
elif isinstance(recurrence, tuple) and len(recurrence) == 3:
constantpower = recurrence[1]
recurrence = recurrence[0]
elif len(recurrence) == 1 and len(recurrence[0]) == 2:
recurrence = recurrence[0][0]
constantpower = 0
elif len(recurrence) == 1 and len(recurrence[0]) == 3:
constantpower = recurrence[0][1]
recurrence = recurrence[0][0]
else:
return [self.series(_recur=i) for i in recurrence]
n = n - int(constantpower)
l = len(recurrence.u0) - 1
k = recurrence.recurrence.order
x = self.x
x0 = self.x0
seq_dmp = recurrence.recurrence.listofpoly
R = recurrence.recurrence.parent.base
K = R.get_field()
seq = [K.new(j.to_list()) for j in seq_dmp]
sub = [-seq[i] / seq[k] for i in range(k)]
sol = list(recurrence.u0)
if l + 1 < n:
# use the initial conditions to find the next term
for i in range(l + 1 - k, n - k):
coeff = sum((DMFsubs(sub[j], i) * sol[i + j]
for j in range(k) if i + j >= 0), start=S.Zero)
sol.append(coeff)
if coefficient:
return sol
ser = sum((x**(i + constantpower) * j for i, j in enumerate(sol)),
start=S.Zero)
if order:
ser += Order(x**(n + int(constantpower)), x)
if x0 != 0:
return ser.subs(x, x - x0)
return ser
def _indicial(self):
"""
Computes roots of the Indicial equation.
"""
if self.x0 != 0:
return self.shift_x(self.x0)._indicial()
list_coeff = self.annihilator.listofpoly
R = self.annihilator.parent.base
x = self.x
s = R.zero
y = R.one
def _pole_degree(poly):
root_all = roots(R.to_sympy(poly), x, filter='Z')
if 0 in root_all.keys():
return root_all[0]
else:
return 0
degree = max(j.degree() for j in list_coeff)
inf = 10 * (max(1, degree) + max(1, self.annihilator.order))
deg = lambda q: inf if q.is_zero else _pole_degree(q)
b = min(deg(q) - j for j, q in enumerate(list_coeff))
for i, j in enumerate(list_coeff):
listofdmp = j.all_coeffs()
degree = len(listofdmp) - 1
if 0 <= i + b <= degree:
s = s + listofdmp[degree - i - b] * y
y *= R.from_sympy(x - i)
return roots(R.to_sympy(s), x)
def evalf(self, points, method='RK4', h=0.05, derivatives=False):
r"""
Finds numerical value of a holonomic function using numerical methods.
(RK4 by default). A set of points (real or complex) must be provided
which will be the path for the numerical integration.
Explanation
===========
The path should be given as a list :math:`[x_1, x_2, \dots x_n]`. The numerical
values will be computed at each point in this order
:math:`x_1 \rightarrow x_2 \rightarrow x_3 \dots \rightarrow x_n`.
Returns values of the function at :math:`x_1, x_2, \dots x_n` in a list.
Examples
========
>>> from sympy.holonomic.holonomic import HolonomicFunction, DifferentialOperators
>>> from sympy import QQ
>>> from sympy import symbols
>>> x = symbols('x')
>>> R, Dx = DifferentialOperators(QQ.old_poly_ring(x),'Dx')
A straight line on the real axis from (0 to 1)
>>> r = [0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1]
Runge-Kutta 4th order on e^x from 0.1 to 1.
Exact solution at 1 is 2.71828182845905
>>> HolonomicFunction(Dx - 1, x, 0, [1]).evalf(r)
[1.10517083333333, 1.22140257085069, 1.34985849706254, 1.49182424008069,
1.64872063859684, 1.82211796209193, 2.01375162659678, 2.22553956329232,
2.45960141378007, 2.71827974413517]
Euler's method for the same
>>> HolonomicFunction(Dx - 1, x, 0, [1]).evalf(r, method='Euler')
[1.1, 1.21, 1.331, 1.4641, 1.61051, 1.771561, 1.9487171, 2.14358881,
2.357947691, 2.5937424601]
One can also observe that the value obtained using Runge-Kutta 4th order
is much more accurate than Euler's method.
"""
from sympy.holonomic.numerical import _evalf
lp = False
# if a point `b` is given instead of a mesh
if not hasattr(points, "__iter__"):
lp = True
b = S(points)
if self.x0 == b:
return _evalf(self, [b], method=method, derivatives=derivatives)[-1]
if not b.is_Number:
raise NotImplementedError
a = self.x0
if a > b:
h = -h
n = int((b - a) / h)
points = [a + h]
for i in range(n - 1):
points.append(points[-1] + h)
for i in roots(self.annihilator.parent.base.to_sympy(self.annihilator.listofpoly[-1]), self.x):
if i == self.x0 or i in points:
raise SingularityError(self, i)
if lp:
return _evalf(self, points, method=method, derivatives=derivatives)[-1]
return _evalf(self, points, method=method, derivatives=derivatives)
def change_x(self, z):
"""
Changes only the variable of Holonomic Function, for internal
purposes. For composition use HolonomicFunction.composition()
"""
dom = self.annihilator.parent.base.dom
R = dom.old_poly_ring(z)
parent, _ = DifferentialOperators(R, 'Dx')
sol = [R(j.to_list()) for j in self.annihilator.listofpoly]
sol = DifferentialOperator(sol, parent)
return HolonomicFunction(sol, z, self.x0, self.y0)
def shift_x(self, a):
"""
Substitute `x + a` for `x`.
"""
x = self.x
listaftershift = self.annihilator.listofpoly
base = self.annihilator.parent.base
sol = [base.from_sympy(base.to_sympy(i).subs(x, x + a)) for i in listaftershift]
sol = DifferentialOperator(sol, self.annihilator.parent)
x0 = self.x0 - a
if not self._have_init_cond():
return HolonomicFunction(sol, x)
return HolonomicFunction(sol, x, x0, self.y0)
def to_hyper(self, as_list=False, _recur=None):
r"""
Returns a hypergeometric function (or linear combination of them)
representing the given holonomic function.
Explanation
===========
Returns an answer of the form:
`a_1 \cdot x^{b_1} \cdot{hyper()} + a_2 \cdot x^{b_2} \cdot{hyper()} \dots`
This is very useful as one can now use ``hyperexpand`` to find the
symbolic expressions/functions.
Examples
========
>>> from sympy.holonomic.holonomic import HolonomicFunction, DifferentialOperators
>>> from sympy import ZZ
>>> from sympy import symbols
>>> x = symbols('x')
>>> R, Dx = DifferentialOperators(ZZ.old_poly_ring(x),'Dx')
>>> # sin(x)
>>> HolonomicFunction(Dx**2 + 1, x, 0, [0, 1]).to_hyper()
x*hyper((), (3/2,), -x**2/4)
>>> # exp(x)
>>> HolonomicFunction(Dx - 1, x, 0, [1]).to_hyper()
hyper((), (), x)
See Also
========
from_hyper, from_meijerg
"""
if _recur is None:
recurrence = self.to_sequence()
else:
recurrence = _recur
if isinstance(recurrence, tuple) and len(recurrence) == 2:
smallest_n = recurrence[1]
recurrence = recurrence[0]
constantpower = 0
elif isinstance(recurrence, tuple) and len(recurrence) == 3:
smallest_n = recurrence[2]
constantpower = recurrence[1]
recurrence = recurrence[0]
elif len(recurrence) == 1 and len(recurrence[0]) == 2:
smallest_n = recurrence[0][1]
recurrence = recurrence[0][0]
constantpower = 0
elif len(recurrence) == 1 and len(recurrence[0]) == 3:
smallest_n = recurrence[0][2]
constantpower = recurrence[0][1]
recurrence = recurrence[0][0]
else:
sol = self.to_hyper(as_list=as_list, _recur=recurrence[0])
for i in recurrence[1:]:
sol += self.to_hyper(as_list=as_list, _recur=i)
return sol
u0 = recurrence.u0
r = recurrence.recurrence
x = self.x
x0 = self.x0
# order of the recurrence relation
m = r.order
# when no recurrence exists, and the power series have finite terms
if m == 0:
nonzeroterms = roots(r.parent.base.to_sympy(r.listofpoly[0]), recurrence.n, filter='R')
sol = S.Zero
for j, i in enumerate(nonzeroterms):
if i < 0 or not int_valued(i):
continue
i = int(i)
if i < len(u0):
if isinstance(u0[i], (PolyElement, FracElement)):
u0[i] = u0[i].as_expr()
sol += u0[i] * x**i
else:
sol += Symbol('C_%s' %j) * x**i
if isinstance(sol, (PolyElement, FracElement)):
sol = sol.as_expr() * x**constantpower
else:
sol = sol * x**constantpower
if as_list:
if x0 != 0:
return [(sol.subs(x, x - x0), )]
return [(sol, )]
if x0 != 0:
return sol.subs(x, x - x0)
return sol
if smallest_n + m > len(u0):
raise NotImplementedError("Can't compute sufficient Initial Conditions")
# check if the recurrence represents a hypergeometric series
if any(i != r.parent.base.zero for i in r.listofpoly[1:-1]):
raise NotHyperSeriesError(self, self.x0)
a = r.listofpoly[0]
b = r.listofpoly[-1]
# the constant multiple of argument of hypergeometric function
if isinstance(a.LC(), (PolyElement, FracElement)):
c = - (S(a.LC().as_expr()) * m**(a.degree())) / (S(b.LC().as_expr()) * m**(b.degree()))
else:
c = - (S(a.LC()) * m**(a.degree())) / (S(b.LC()) * m**(b.degree()))
sol = 0
arg1 = roots(r.parent.base.to_sympy(a), recurrence.n)
arg2 = roots(r.parent.base.to_sympy(b), recurrence.n)
# iterate through the initial conditions to find
# the hypergeometric representation of the given
# function.
# The answer will be a linear combination
# of different hypergeometric series which satisfies
# the recurrence.
if as_list:
listofsol = []
for i in range(smallest_n + m):
# if the recurrence relation doesn't hold for `n = i`,
# then a Hypergeometric representation doesn't exist.
# add the algebraic term a * x**i to the solution,
# where a is u0[i]
if i < smallest_n:
if as_list:
listofsol.append(((S(u0[i]) * x**(i+constantpower)).subs(x, x-x0), ))
else:
sol += S(u0[i]) * x**i
continue
# if the coefficient u0[i] is zero, then the
# independent hypergeomtric series starting with
# x**i is not a part of the answer.
if S(u0[i]) == 0:
continue
ap = []
bq = []
# substitute m * n + i for n
for k in ordered(arg1.keys()):
ap.extend([nsimplify((i - k) / m)] * arg1[k])
for k in ordered(arg2.keys()):
bq.extend([nsimplify((i - k) / m)] * arg2[k])
# convention of (k + 1) in the denominator
if 1 in bq:
bq.remove(1)
else:
ap.append(1)
if as_list:
listofsol.append(((S(u0[i])*x**(i+constantpower)).subs(x, x-x0), (hyper(ap, bq, c*x**m)).subs(x, x-x0)))
else:
sol += S(u0[i]) * hyper(ap, bq, c * x**m) * x**i
if as_list:
return listofsol
sol = sol * x**constantpower
if x0 != 0:
return sol.subs(x, x - x0)
return sol
def to_expr(self):
"""
Converts a Holonomic Function back to elementary functions.
Examples
========
>>> from sympy.holonomic.holonomic import HolonomicFunction, DifferentialOperators
>>> from sympy import ZZ
>>> from sympy import symbols, S
>>> x = symbols('x')
>>> R, Dx = DifferentialOperators(ZZ.old_poly_ring(x),'Dx')
>>> HolonomicFunction(x**2*Dx**2 + x*Dx + (x**2 - 1), x, 0, [0, S(1)/2]).to_expr()
besselj(1, x)
>>> HolonomicFunction((1 + x)*Dx**3 + Dx**2, x, 0, [1, 1, 1]).to_expr()
x*log(x + 1) + log(x + 1) + 1
"""
return hyperexpand(self.to_hyper()).simplify()
def change_ics(self, b, lenics=None):
"""
Changes the point `x0` to ``b`` for initial conditions.
Examples
========
>>> from sympy.holonomic import expr_to_holonomic
>>> from sympy import symbols, sin, exp
>>> x = symbols('x')
>>> expr_to_holonomic(sin(x)).change_ics(1)
HolonomicFunction((1) + (1)*Dx**2, x, 1, [sin(1), cos(1)])
>>> expr_to_holonomic(exp(x)).change_ics(2)
HolonomicFunction((-1) + (1)*Dx, x, 2, [exp(2)])
"""
symbolic = True
if lenics is None and len(self.y0) > self.annihilator.order:
lenics = len(self.y0)
dom = self.annihilator.parent.base.domain
try:
sol = expr_to_holonomic(self.to_expr(), x=self.x, x0=b, lenics=lenics, domain=dom)
except (NotPowerSeriesError, NotHyperSeriesError):
symbolic = False
if symbolic and sol.x0 == b:
return sol
y0 = self.evalf(b, derivatives=True)
return HolonomicFunction(self.annihilator, self.x, b, y0)
def to_meijerg(self):
"""
Returns a linear combination of Meijer G-functions.
Examples
========
>>> from sympy.holonomic import expr_to_holonomic
>>> from sympy import sin, cos, hyperexpand, log, symbols
>>> x = symbols('x')
>>> hyperexpand(expr_to_holonomic(cos(x) + sin(x)).to_meijerg())
sin(x) + cos(x)
>>> hyperexpand(expr_to_holonomic(log(x)).to_meijerg()).simplify()
log(x)
See Also
========
to_hyper
"""
# convert to hypergeometric first
rep = self.to_hyper(as_list=True)
sol = S.Zero
for i in rep:
if len(i) == 1:
sol += i[0]
elif len(i) == 2:
sol += i[0] * _hyper_to_meijerg(i[1])
return sol
def from_hyper(func, x0=0, evalf=False):
r"""
Converts a hypergeometric function to holonomic.
``func`` is the Hypergeometric Function and ``x0`` is the point at
which initial conditions are required.
Examples
========
>>> from sympy.holonomic.holonomic import from_hyper
>>> from sympy import symbols, hyper, S
>>> x = symbols('x')
>>> from_hyper(hyper([], [S(3)/2], x**2/4))
HolonomicFunction((-x) + (2)*Dx + (x)*Dx**2, x, 1, [sinh(1), -sinh(1) + cosh(1)])
"""
a = func.ap
b = func.bq
z = func.args[2]
x = z.atoms(Symbol).pop()
R, Dx = DifferentialOperators(QQ.old_poly_ring(x), 'Dx')
# generalized hypergeometric differential equation
xDx = x*Dx
r1 = 1
for ai in a: # XXX gives sympify error if Mul is used with list of all factors
r1 *= xDx + ai
xDx_1 = xDx - 1
# r2 = Mul(*([Dx] + [xDx_1 + bi for bi in b])) # XXX gives sympify error
r2 = Dx
for bi in b:
r2 *= xDx_1 + bi
sol = r1 - r2
simp = hyperexpand(func)
if simp in (Infinity, NegativeInfinity):
return HolonomicFunction(sol, x).composition(z)
def _find_conditions(simp, x, x0, order, evalf=False):
y0 = []
for i in range(order):
if evalf:
val = simp.subs(x, x0).evalf()
else:
val = simp.subs(x, x0)
# return None if it is Infinite or NaN
if val.is_finite is False or isinstance(val, NaN):
return None
y0.append(val)
simp = simp.diff(x)
return y0
# if the function is known symbolically
if not isinstance(simp, hyper):
y0 = _find_conditions(simp, x, x0, sol.order)
while not y0:
# if values don't exist at 0, then try to find initial
# conditions at 1. If it doesn't exist at 1 too then
# try 2 and so on.
x0 += 1
y0 = _find_conditions(simp, x, x0, sol.order)
return HolonomicFunction(sol, x).composition(z, x0, y0)
if isinstance(simp, hyper):
x0 = 1
# use evalf if the function can't be simplified
y0 = _find_conditions(simp, x, x0, sol.order, evalf)
while not y0:
x0 += 1
y0 = _find_conditions(simp, x, x0, sol.order, evalf)
return HolonomicFunction(sol, x).composition(z, x0, y0)
return HolonomicFunction(sol, x).composition(z)
def from_meijerg(func, x0=0, evalf=False, initcond=True, domain=QQ):
"""
Converts a Meijer G-function to Holonomic.
``func`` is the G-Function and ``x0`` is the point at
which initial conditions are required.
Examples
========
>>> from sympy.holonomic.holonomic import from_meijerg
>>> from sympy import symbols, meijerg, S
>>> x = symbols('x')
>>> from_meijerg(meijerg(([], []), ([S(1)/2], [0]), x**2/4))
HolonomicFunction((1) + (1)*Dx**2, x, 0, [0, 1/sqrt(pi)])
"""
a = func.ap
b = func.bq
n = len(func.an)
m = len(func.bm)
p = len(a)
z = func.args[2]
x = z.atoms(Symbol).pop()
R, Dx = DifferentialOperators(domain.old_poly_ring(x), 'Dx')
# compute the differential equation satisfied by the
# Meijer G-function.
xDx = x*Dx
xDx1 = xDx + 1
r1 = x*(-1)**(m + n - p)
for ai in a: # XXX gives sympify error if args given in list
r1 *= xDx1 - ai
# r2 = Mul(*[xDx - bi for bi in b]) # gives sympify error
r2 = 1
for bi in b:
r2 *= xDx - bi
sol = r1 - r2
if not initcond:
return HolonomicFunction(sol, x).composition(z)
simp = hyperexpand(func)
if simp in (Infinity, NegativeInfinity):
return HolonomicFunction(sol, x).composition(z)
def _find_conditions(simp, x, x0, order, evalf=False):
y0 = []
for i in range(order):
if evalf:
val = simp.subs(x, x0).evalf()
else:
val = simp.subs(x, x0)
if val.is_finite is False or isinstance(val, NaN):
return None
y0.append(val)
simp = simp.diff(x)
return y0
# computing initial conditions
if not isinstance(simp, meijerg):
y0 = _find_conditions(simp, x, x0, sol.order)
while not y0:
x0 += 1
y0 = _find_conditions(simp, x, x0, sol.order)
return HolonomicFunction(sol, x).composition(z, x0, y0)
if isinstance(simp, meijerg):
x0 = 1
y0 = _find_conditions(simp, x, x0, sol.order, evalf)
while not y0:
x0 += 1
y0 = _find_conditions(simp, x, x0, sol.order, evalf)
return HolonomicFunction(sol, x).composition(z, x0, y0)
return HolonomicFunction(sol, x).composition(z)
x_1 = Dummy('x_1')
_lookup_table = None
domain_for_table = None
from sympy.integrals.meijerint import _mytype
def expr_to_holonomic(func, x=None, x0=0, y0=None, lenics=None, domain=None, initcond=True):
"""
Converts a function or an expression to a holonomic function.
Parameters
==========
func:
The expression to be converted.
x:
variable for the function.
x0:
point at which initial condition must be computed.
y0:
One can optionally provide initial condition if the method
is not able to do it automatically.
lenics:
Number of terms in the initial condition. By default it is
equal to the order of the annihilator.
domain:
Ground domain for the polynomials in ``x`` appearing as coefficients
in the annihilator.
initcond:
Set it false if you do not want the initial conditions to be computed.
Examples
========
>>> from sympy.holonomic.holonomic import expr_to_holonomic
>>> from sympy import sin, exp, symbols
>>> x = symbols('x')
>>> expr_to_holonomic(sin(x))
HolonomicFunction((1) + (1)*Dx**2, x, 0, [0, 1])
>>> expr_to_holonomic(exp(x))
HolonomicFunction((-1) + (1)*Dx, x, 0, [1])
See Also
========
sympy.integrals.meijerint._rewrite1, _convert_poly_rat_alg, _create_table
"""
func = sympify(func)
syms = func.free_symbols
if not x:
if len(syms) == 1:
x= syms.pop()
else:
raise ValueError("Specify the variable for the function")
elif x in syms:
syms.remove(x)
extra_syms = list(syms)
if domain is None:
if func.has(Float):
domain = RR
else:
domain = QQ
if len(extra_syms) != 0:
domain = domain[extra_syms].get_field()
# try to convert if the function is polynomial or rational
solpoly = _convert_poly_rat_alg(func, x, x0=x0, y0=y0, lenics=lenics, domain=domain, initcond=initcond)
if solpoly:
return solpoly
# create the lookup table
global _lookup_table, domain_for_table
if not _lookup_table:
domain_for_table = domain
_lookup_table = {}
_create_table(_lookup_table, domain=domain)
elif domain != domain_for_table:
domain_for_table = domain
_lookup_table = {}
_create_table(_lookup_table, domain=domain)
# use the table directly to convert to Holonomic
if func.is_Function:
f = func.subs(x, x_1)
t = _mytype(f, x_1)
if t in _lookup_table:
l = _lookup_table[t]
sol = l[0][1].change_x(x)
else:
sol = _convert_meijerint(func, x, initcond=False, domain=domain)
if not sol:
raise NotImplementedError
if y0:
sol.y0 = y0
if y0 or not initcond:
sol.x0 = x0
return sol
if not lenics:
lenics = sol.annihilator.order
_y0 = _find_conditions(func, x, x0, lenics)
while not _y0:
x0 += 1
_y0 = _find_conditions(func, x, x0, lenics)
return HolonomicFunction(sol.annihilator, x, x0, _y0)
if y0 or not initcond:
sol = sol.composition(func.args[0])
if y0:
sol.y0 = y0
sol.x0 = x0
return sol
if not lenics:
lenics = sol.annihilator.order
_y0 = _find_conditions(func, x, x0, lenics)
while not _y0:
x0 += 1
_y0 = _find_conditions(func, x, x0, lenics)
return sol.composition(func.args[0], x0, _y0)
# iterate through the expression recursively
args = func.args
f = func.func
sol = expr_to_holonomic(args[0], x=x, initcond=False, domain=domain)
if f is Add:
for i in range(1, len(args)):
sol += expr_to_holonomic(args[i], x=x, initcond=False, domain=domain)
elif f is Mul:
for i in range(1, len(args)):
sol *= expr_to_holonomic(args[i], x=x, initcond=False, domain=domain)
elif f is Pow:
sol = sol**args[1]
sol.x0 = x0
if not sol:
raise NotImplementedError
if y0:
sol.y0 = y0
if y0 or not initcond:
return sol
if sol.y0:
return sol
if not lenics:
lenics = sol.annihilator.order
if sol.annihilator.is_singular(x0):
r = sol._indicial()
l = list(r)
if len(r) == 1 and r[l[0]] == S.One:
r = l[0]
g = func / (x - x0)**r
singular_ics = _find_conditions(g, x, x0, lenics)
singular_ics = [j / factorial(i) for i, j in enumerate(singular_ics)]
y0 = {r:singular_ics}
return HolonomicFunction(sol.annihilator, x, x0, y0)
_y0 = _find_conditions(func, x, x0, lenics)
while not _y0:
x0 += 1
_y0 = _find_conditions(func, x, x0, lenics)
return HolonomicFunction(sol.annihilator, x, x0, _y0)
## Some helper functions ##
def _normalize(list_of, parent, negative=True):
"""
Normalize a given annihilator
"""
num = []
denom = []
base = parent.base
K = base.get_field()
lcm_denom = base.from_sympy(S.One)
list_of_coeff = []
# convert polynomials to the elements of associated
# fraction field
for i, j in enumerate(list_of):
if isinstance(j, base.dtype):
list_of_coeff.append(K.new(j.to_list()))
elif not isinstance(j, K.dtype):
list_of_coeff.append(K.from_sympy(sympify(j)))
else:
list_of_coeff.append(j)
# corresponding numerators of the sequence of polynomials
num.append(list_of_coeff[i].numer())
# corresponding denominators
denom.append(list_of_coeff[i].denom())
# lcm of denominators in the coefficients
for i in denom:
lcm_denom = i.lcm(lcm_denom)
if negative:
lcm_denom = -lcm_denom
lcm_denom = K.new(lcm_denom.to_list())
# multiply the coefficients with lcm
for i, j in enumerate(list_of_coeff):
list_of_coeff[i] = j * lcm_denom
gcd_numer = base((list_of_coeff[-1].numer() / list_of_coeff[-1].denom()).to_list())
# gcd of numerators in the coefficients
for i in num:
gcd_numer = i.gcd(gcd_numer)
gcd_numer = K.new(gcd_numer.to_list())
# divide all the coefficients by the gcd
for i, j in enumerate(list_of_coeff):
frac_ans = j / gcd_numer
list_of_coeff[i] = base((frac_ans.numer() / frac_ans.denom()).to_list())
return DifferentialOperator(list_of_coeff, parent)
def _derivate_diff_eq(listofpoly, K):
"""
Let a differential equation a0(x)y(x) + a1(x)y'(x) + ... = 0
where a0, a1,... are polynomials or rational functions. The function
returns b0, b1, b2... such that the differential equation
b0(x)y(x) + b1(x)y'(x) +... = 0 is formed after differentiating the
former equation.
"""
sol = []
a = len(listofpoly) - 1
sol.append(DMFdiff(listofpoly[0], K))
for i, j in enumerate(listofpoly[1:]):
sol.append(DMFdiff(j, K) + listofpoly[i])
sol.append(listofpoly[a])
return sol
def _hyper_to_meijerg(func):
"""
Converts a `hyper` to meijerg.
"""
ap = func.ap
bq = func.bq
if any(i <= 0 and int(i) == i for i in ap):
return hyperexpand(func)
z = func.args[2]
# parameters of the `meijerg` function.
an = (1 - i for i in ap)
anp = ()
bm = (S.Zero, )
bmq = (1 - i for i in bq)
k = S.One
for i in bq:
k = k * gamma(i)
for i in ap:
k = k / gamma(i)
return k * meijerg(an, anp, bm, bmq, -z)
def _add_lists(list1, list2):
"""Takes polynomial sequences of two annihilators a and b and returns
the list of polynomials of sum of a and b.
"""
if len(list1) <= len(list2):
sol = [a + b for a, b in zip(list1, list2)] + list2[len(list1):]
else:
sol = [a + b for a, b in zip(list1, list2)] + list1[len(list2):]
return sol
def _extend_y0(Holonomic, n):
"""
Tries to find more initial conditions by substituting the initial
value point in the differential equation.
"""
if Holonomic.annihilator.is_singular(Holonomic.x0) or Holonomic.is_singularics() == True:
return Holonomic.y0
annihilator = Holonomic.annihilator
a = annihilator.order
listofpoly = []
y0 = Holonomic.y0
R = annihilator.parent.base
K = R.get_field()
for j in annihilator.listofpoly:
if isinstance(j, annihilator.parent.base.dtype):
listofpoly.append(K.new(j.to_list()))
if len(y0) < a or n <= len(y0):
return y0
list_red = [-listofpoly[i] / listofpoly[a]
for i in range(a)]
y1 = y0[:min(len(y0), a)]
for _ in range(n - a):
sol = 0
for a, b in zip(y1, list_red):
r = DMFsubs(b, Holonomic.x0)
if not getattr(r, 'is_finite', True):
return y0
if isinstance(r, (PolyElement, FracElement)):
r = r.as_expr()
sol += a * r
y1.append(sol)
list_red = _derivate_diff_eq(list_red, K)
return y0 + y1[len(y0):]
def DMFdiff(frac, K):
# differentiate a DMF object represented as p/q
if not isinstance(frac, DMF):
return frac.diff()
p = K.numer(frac)
q = K.denom(frac)
sol_num = - p * q.diff() + q * p.diff()
sol_denom = q**2
return K((sol_num.to_list(), sol_denom.to_list()))
def DMFsubs(frac, x0, mpm=False):
# substitute the point x0 in DMF object of the form p/q
if not isinstance(frac, DMF):
return frac
p = frac.num
q = frac.den
sol_p = S.Zero
sol_q = S.Zero
if mpm:
from mpmath import mp
for i, j in enumerate(reversed(p)):
if mpm:
j = sympify(j)._to_mpmath(mp.prec)
sol_p += j * x0**i
for i, j in enumerate(reversed(q)):
if mpm:
j = sympify(j)._to_mpmath(mp.prec)
sol_q += j * x0**i
if isinstance(sol_p, (PolyElement, FracElement)):
sol_p = sol_p.as_expr()
if isinstance(sol_q, (PolyElement, FracElement)):
sol_q = sol_q.as_expr()
return sol_p / sol_q
def _convert_poly_rat_alg(func, x, x0=0, y0=None, lenics=None, domain=QQ, initcond=True):
"""
Converts polynomials, rationals and algebraic functions to holonomic.
"""
ispoly = func.is_polynomial()
if not ispoly:
israt = func.is_rational_function()
else:
israt = True
if not (ispoly or israt):
basepoly, ratexp = func.as_base_exp()
if basepoly.is_polynomial() and ratexp.is_Number:
if isinstance(ratexp, Float):
ratexp = nsimplify(ratexp)
m, n = ratexp.p, ratexp.q
is_alg = True
else:
is_alg = False
else:
is_alg = True
if not (ispoly or israt or is_alg):
return None
R = domain.old_poly_ring(x)
_, Dx = DifferentialOperators(R, 'Dx')
# if the function is constant
if not func.has(x):
return HolonomicFunction(Dx, x, 0, [func])
if ispoly:
# differential equation satisfied by polynomial
sol = func * Dx - func.diff(x)
sol = _normalize(sol.listofpoly, sol.parent, negative=False)
is_singular = sol.is_singular(x0)
# try to compute the conditions for singular points
if y0 is None and x0 == 0 and is_singular:
rep = R.from_sympy(func).to_list()
for i, j in enumerate(reversed(rep)):
if j == 0:
continue
coeff = list(reversed(rep))[i:]
indicial = i
break
for i, j in enumerate(coeff):
if isinstance(j, (PolyElement, FracElement)):
coeff[i] = j.as_expr()
y0 = {indicial: S(coeff)}
elif israt:
p, q = func.as_numer_denom()
# differential equation satisfied by rational
sol = p * q * Dx + p * q.diff(x) - q * p.diff(x)
sol = _normalize(sol.listofpoly, sol.parent, negative=False)
elif is_alg:
sol = n * (x / m) * Dx - 1
sol = HolonomicFunction(sol, x).composition(basepoly).annihilator
is_singular = sol.is_singular(x0)
# try to compute the conditions for singular points
if y0 is None and x0 == 0 and is_singular and \
(lenics is None or lenics <= 1):
rep = R.from_sympy(basepoly).to_list()
for i, j in enumerate(reversed(rep)):
if j == 0:
continue
if isinstance(j, (PolyElement, FracElement)):
j = j.as_expr()
coeff = S(j)**ratexp
indicial = S(i) * ratexp
break
if isinstance(coeff, (PolyElement, FracElement)):
coeff = coeff.as_expr()
y0 = {indicial: S([coeff])}
if y0 or not initcond:
return HolonomicFunction(sol, x, x0, y0)
if not lenics:
lenics = sol.order
if sol.is_singular(x0):
r = HolonomicFunction(sol, x, x0)._indicial()
l = list(r)
if len(r) == 1 and r[l[0]] == S.One:
r = l[0]
g = func / (x - x0)**r
singular_ics = _find_conditions(g, x, x0, lenics)
singular_ics = [j / factorial(i) for i, j in enumerate(singular_ics)]
y0 = {r:singular_ics}
return HolonomicFunction(sol, x, x0, y0)
y0 = _find_conditions(func, x, x0, lenics)
while not y0:
x0 += 1
y0 = _find_conditions(func, x, x0, lenics)
return HolonomicFunction(sol, x, x0, y0)
def _convert_meijerint(func, x, initcond=True, domain=QQ):
args = meijerint._rewrite1(func, x)
if args:
fac, po, g, _ = args
else:
return None
# lists for sum of meijerg functions
fac_list = [fac * i[0] for i in g]
t = po.as_base_exp()
s = t[1] if t[0] == x else S.Zero
po_list = [s + i[1] for i in g]
G_list = [i[2] for i in g]
# finds meijerg representation of x**s * meijerg(a1 ... ap, b1 ... bq, z)
def _shift(func, s):
z = func.args[-1]
if z.has(I):
z = z.subs(exp_polar, exp)
d = z.collect(x, evaluate=False)
b = list(d)[0]
a = d[b]
t = b.as_base_exp()
b = t[1] if t[0] == x else S.Zero
r = s / b
an = (i + r for i in func.args[0][0])
ap = (i + r for i in func.args[0][1])
bm = (i + r for i in func.args[1][0])
bq = (i + r for i in func.args[1][1])
return a**-r, meijerg((an, ap), (bm, bq), z)
coeff, m = _shift(G_list[0], po_list[0])
sol = fac_list[0] * coeff * from_meijerg(m, initcond=initcond, domain=domain)
# add all the meijerg functions after converting to holonomic
for i in range(1, len(G_list)):
coeff, m = _shift(G_list[i], po_list[i])
sol += fac_list[i] * coeff * from_meijerg(m, initcond=initcond, domain=domain)
return sol
def _create_table(table, domain=QQ):
"""
Creates the look-up table. For a similar implementation
see meijerint._create_lookup_table.
"""
def add(formula, annihilator, arg, x0=0, y0=()):
"""
Adds a formula in the dictionary
"""
table.setdefault(_mytype(formula, x_1), []).append((formula,
HolonomicFunction(annihilator, arg, x0, y0)))
R = domain.old_poly_ring(x_1)
_, Dx = DifferentialOperators(R, 'Dx')
# add some basic functions
add(sin(x_1), Dx**2 + 1, x_1, 0, [0, 1])
add(cos(x_1), Dx**2 + 1, x_1, 0, [1, 0])
add(exp(x_1), Dx - 1, x_1, 0, 1)
add(log(x_1), Dx + x_1*Dx**2, x_1, 1, [0, 1])
add(erf(x_1), 2*x_1*Dx + Dx**2, x_1, 0, [0, 2/sqrt(pi)])
add(erfc(x_1), 2*x_1*Dx + Dx**2, x_1, 0, [1, -2/sqrt(pi)])
add(erfi(x_1), -2*x_1*Dx + Dx**2, x_1, 0, [0, 2/sqrt(pi)])
add(sinh(x_1), Dx**2 - 1, x_1, 0, [0, 1])
add(cosh(x_1), Dx**2 - 1, x_1, 0, [1, 0])
add(sinc(x_1), x_1 + 2*Dx + x_1*Dx**2, x_1)
add(Si(x_1), x_1*Dx + 2*Dx**2 + x_1*Dx**3, x_1)
add(Ci(x_1), x_1*Dx + 2*Dx**2 + x_1*Dx**3, x_1)
add(Shi(x_1), -x_1*Dx + 2*Dx**2 + x_1*Dx**3, x_1)
def _find_conditions(func, x, x0, order):
y0 = []
for i in range(order):
val = func.subs(x, x0)
if isinstance(val, NaN):
val = limit(func, x, x0)
if val.is_finite is False or isinstance(val, NaN):
return None
y0.append(val)
func = func.diff(x)
return y0
PK ]ZZZdv=� � " sympy/holonomic/holonomicerrors.py""" Common Exceptions for `holonomic` module. """
class BaseHolonomicError(Exception):
def new(self, *args):
raise NotImplementedError("abstract base class")
class NotPowerSeriesError(BaseHolonomicError):
def __init__(self, holonomic, x0):
self.holonomic = holonomic
self.x0 = x0
def __str__(self):
s = 'A Power Series does not exists for '
s += str(self.holonomic)
s += ' about %s.' %self.x0
return s
class NotHolonomicError(BaseHolonomicError):
def __init__(self, m):
self.m = m
def __str__(self):
return self.m
class SingularityError(BaseHolonomicError):
def __init__(self, holonomic, x0):
self.holonomic = holonomic
self.x0 = x0
def __str__(self):
s = str(self.holonomic)
s += ' has a singularity at %s.' %self.x0
return s
class NotHyperSeriesError(BaseHolonomicError):
def __init__(self, holonomic, x0):
self.holonomic = holonomic
self.x0 = x0
def __str__(self):
s = 'Power series expansion of '
s += str(self.holonomic)
s += ' about %s is not hypergeometric' %self.x0
return s
PK ]ZZZ���~�
�
sympy/holonomic/numerical.py"""Numerical Methods for Holonomic Functions"""
from sympy.core.sympify import sympify
from sympy.holonomic.holonomic import DMFsubs
from mpmath import mp
def _evalf(func, points, derivatives=False, method='RK4'):
"""
Numerical methods for numerical integration along a given set of
points in the complex plane.
"""
ann = func.annihilator
a = ann.order
R = ann.parent.base
K = R.get_field()
if method == 'Euler':
meth = _euler
else:
meth = _rk4
dmf = []
for j in ann.listofpoly:
dmf.append(K.new(j.to_list()))
red = [-dmf[i] / dmf[a] for i in range(a)]
y0 = func.y0
if len(y0) < a:
raise TypeError("Not Enough Initial Conditions")
x0 = func.x0
sol = [meth(red, x0, points[0], y0, a)]
for i, j in enumerate(points[1:]):
sol.append(meth(red, points[i], j, sol[-1], a))
if not derivatives:
return [sympify(i[0]) for i in sol]
else:
return sympify(sol)
def _euler(red, x0, x1, y0, a):
"""
Euler's method for numerical integration.
From x0 to x1 with initial values given at x0 as vector y0.
"""
A = sympify(x0)._to_mpmath(mp.prec)
B = sympify(x1)._to_mpmath(mp.prec)
y_0 = [sympify(i)._to_mpmath(mp.prec) for i in y0]
h = B - A
f_0 = y_0[1:]
f_0_n = 0
for i in range(a):
f_0_n += sympify(DMFsubs(red[i], A, mpm=True))._to_mpmath(mp.prec) * y_0[i]
f_0.append(f_0_n)
sol = []
for i in range(a):
sol.append(y_0[i] + h * f_0[i])
return sol
def _rk4(red, x0, x1, y0, a):
"""
Runge-Kutta 4th order numerical method.
"""
A = sympify(x0)._to_mpmath(mp.prec)
B = sympify(x1)._to_mpmath(mp.prec)
y_0 = [sympify(i)._to_mpmath(mp.prec) for i in y0]
h = B - A
f_0_n = 0
f_1_n = 0
f_2_n = 0
f_3_n = 0
f_0 = y_0[1:]
for i in range(a):
f_0_n += sympify(DMFsubs(red[i], A, mpm=True))._to_mpmath(mp.prec) * y_0[i]
f_0.append(f_0_n)
f_1 = [y_0[i] + f_0[i]*h/2 for i in range(1, a)]
for i in range(a):
f_1_n += sympify(DMFsubs(red[i], A + h/2, mpm=True))._to_mpmath(mp.prec) * (y_0[i] + f_0[i]*h/2)
f_1.append(f_1_n)
f_2 = [y_0[i] + f_1[i]*h/2 for i in range(1, a)]
for i in range(a):
f_2_n += sympify(DMFsubs(red[i], A + h/2, mpm=True))._to_mpmath(mp.prec) * (y_0[i] + f_1[i]*h/2)
f_2.append(f_2_n)
f_3 = [y_0[i] + f_2[i]*h for i in range(1, a)]
for i in range(a):
f_3_n += sympify(DMFsubs(red[i], A + h, mpm=True))._to_mpmath(mp.prec) * (y_0[i] + f_2[i]*h)
f_3.append(f_3_n)
sol = []
for i in range(a):
sol.append(y_0[i] + h * (f_0[i]+2*f_1[i]+2*f_2[i]+f_3[i])/6)
return sol
PK ]ZZZ�S�* �* sympy/holonomic/recurrence.py"""Recurrence Operators"""
from sympy.core.singleton import S
from sympy.core.symbol import (Symbol, symbols)
from sympy.printing import sstr
from sympy.core.sympify import sympify
def RecurrenceOperators(base, generator):
"""
Returns an Algebra of Recurrence Operators and the operator for
shifting i.e. the `Sn` operator.
The first argument needs to be the base polynomial ring for the algebra
and the second argument must be a generator which can be either a
noncommutative Symbol or a string.
Examples
========
>>> from sympy import ZZ
>>> from sympy import symbols
>>> from sympy.holonomic.recurrence import RecurrenceOperators
>>> n = symbols('n', integer=True)
>>> R, Sn = RecurrenceOperators(ZZ.old_poly_ring(n), 'Sn')
"""
ring = RecurrenceOperatorAlgebra(base, generator)
return (ring, ring.shift_operator)
class RecurrenceOperatorAlgebra:
"""
A Recurrence Operator Algebra is a set of noncommutative polynomials
in intermediate `Sn` and coefficients in a base ring A. It follows the
commutation rule:
Sn * a(n) = a(n + 1) * Sn
This class represents a Recurrence Operator Algebra and serves as the parent ring
for Recurrence Operators.
Examples
========
>>> from sympy import ZZ
>>> from sympy import symbols
>>> from sympy.holonomic.recurrence import RecurrenceOperators
>>> n = symbols('n', integer=True)
>>> R, Sn = RecurrenceOperators(ZZ.old_poly_ring(n), 'Sn')
>>> R
Univariate Recurrence Operator Algebra in intermediate Sn over the base ring
ZZ[n]
See Also
========
RecurrenceOperator
"""
def __init__(self, base, generator):
# the base ring for the algebra
self.base = base
# the operator representing shift i.e. `Sn`
self.shift_operator = RecurrenceOperator(
[base.zero, base.one], self)
if generator is None:
self.gen_symbol = symbols('Sn', commutative=False)
else:
if isinstance(generator, str):
self.gen_symbol = symbols(generator, commutative=False)
elif isinstance(generator, Symbol):
self.gen_symbol = generator
def __str__(self):
string = 'Univariate Recurrence Operator Algebra in intermediate '\
+ sstr(self.gen_symbol) + ' over the base ring ' + \
(self.base).__str__()
return string
__repr__ = __str__
def __eq__(self, other):
if self.base == other.base and self.gen_symbol == other.gen_symbol:
return True
else:
return False
def _add_lists(list1, list2):
if len(list1) <= len(list2):
sol = [a + b for a, b in zip(list1, list2)] + list2[len(list1):]
else:
sol = [a + b for a, b in zip(list1, list2)] + list1[len(list2):]
return sol
class RecurrenceOperator:
"""
The Recurrence Operators are defined by a list of polynomials
in the base ring and the parent ring of the Operator.
Explanation
===========
Takes a list of polynomials for each power of Sn and the
parent ring which must be an instance of RecurrenceOperatorAlgebra.
A Recurrence Operator can be created easily using
the operator `Sn`. See examples below.
Examples
========
>>> from sympy.holonomic.recurrence import RecurrenceOperator, RecurrenceOperators
>>> from sympy import ZZ
>>> from sympy import symbols
>>> n = symbols('n', integer=True)
>>> R, Sn = RecurrenceOperators(ZZ.old_poly_ring(n),'Sn')
>>> RecurrenceOperator([0, 1, n**2], R)
(1)Sn + (n**2)Sn**2
>>> Sn*n
(n + 1)Sn
>>> n*Sn*n + 1 - Sn**2*n
(1) + (n**2 + n)Sn + (-n - 2)Sn**2
See Also
========
DifferentialOperatorAlgebra
"""
_op_priority = 20
def __init__(self, list_of_poly, parent):
# the parent ring for this operator
# must be an RecurrenceOperatorAlgebra object
self.parent = parent
# sequence of polynomials in n for each power of Sn
# represents the operator
# convert the expressions into ring elements using from_sympy
if isinstance(list_of_poly, list):
for i, j in enumerate(list_of_poly):
if isinstance(j, int):
list_of_poly[i] = self.parent.base.from_sympy(S(j))
elif not isinstance(j, self.parent.base.dtype):
list_of_poly[i] = self.parent.base.from_sympy(j)
self.listofpoly = list_of_poly
self.order = len(self.listofpoly) - 1
def __mul__(self, other):
"""
Multiplies two Operators and returns another
RecurrenceOperator instance using the commutation rule
Sn * a(n) = a(n + 1) * Sn
"""
listofself = self.listofpoly
base = self.parent.base
if not isinstance(other, RecurrenceOperator):
if not isinstance(other, self.parent.base.dtype):
listofother = [self.parent.base.from_sympy(sympify(other))]
else:
listofother = [other]
else:
listofother = other.listofpoly
# multiply a polynomial `b` with a list of polynomials
def _mul_dmp_diffop(b, listofother):
if isinstance(listofother, list):
sol = []
for i in listofother:
sol.append(i * b)
return sol
else:
return [b * listofother]
sol = _mul_dmp_diffop(listofself[0], listofother)
# compute Sn^i * b
def _mul_Sni_b(b):
sol = [base.zero]
if isinstance(b, list):
for i in b:
j = base.to_sympy(i).subs(base.gens[0], base.gens[0] + S.One)
sol.append(base.from_sympy(j))
else:
j = b.subs(base.gens[0], base.gens[0] + S.One)
sol.append(base.from_sympy(j))
return sol
for i in range(1, len(listofself)):
# find Sn^i * b in ith iteration
listofother = _mul_Sni_b(listofother)
# solution = solution + listofself[i] * (Sn^i * b)
sol = _add_lists(sol, _mul_dmp_diffop(listofself[i], listofother))
return RecurrenceOperator(sol, self.parent)
def __rmul__(self, other):
if not isinstance(other, RecurrenceOperator):
if isinstance(other, int):
other = S(other)
if not isinstance(other, self.parent.base.dtype):
other = (self.parent.base).from_sympy(other)
sol = []
for j in self.listofpoly:
sol.append(other * j)
return RecurrenceOperator(sol, self.parent)
def __add__(self, other):
if isinstance(other, RecurrenceOperator):
sol = _add_lists(self.listofpoly, other.listofpoly)
return RecurrenceOperator(sol, self.parent)
else:
if isinstance(other, int):
other = S(other)
list_self = self.listofpoly
if not isinstance(other, self.parent.base.dtype):
list_other = [((self.parent).base).from_sympy(other)]
else:
list_other = [other]
sol = []
sol.append(list_self[0] + list_other[0])
sol += list_self[1:]
return RecurrenceOperator(sol, self.parent)
__radd__ = __add__
def __sub__(self, other):
return self + (-1) * other
def __rsub__(self, other):
return (-1) * self + other
def __pow__(self, n):
if n == 1:
return self
result = RecurrenceOperator([self.parent.base.one], self.parent)
if n == 0:
return result
# if self is `Sn`
if self.listofpoly == self.parent.shift_operator.listofpoly:
sol = [self.parent.base.zero] * n + [self.parent.base.one]
return RecurrenceOperator(sol, self.parent)
x = self
while True:
if n % 2:
result *= x
n >>= 1
if not n:
break
x *= x
return result
def __str__(self):
listofpoly = self.listofpoly
print_str = ''
for i, j in enumerate(listofpoly):
if j == self.parent.base.zero:
continue
j = self.parent.base.to_sympy(j)
if i == 0:
print_str += '(' + sstr(j) + ')'
continue
if print_str:
print_str += ' + '
if i == 1:
print_str += '(' + sstr(j) + ')Sn'
continue
print_str += '(' + sstr(j) + ')' + 'Sn**' + sstr(i)
return print_str
__repr__ = __str__
def __eq__(self, other):
if isinstance(other, RecurrenceOperator):
if self.listofpoly == other.listofpoly and self.parent == other.parent:
return True
else:
return False
else:
if self.listofpoly[0] == other:
for i in self.listofpoly[1:]:
if i is not self.parent.base.zero:
return False
return True
else:
return False
class HolonomicSequence:
"""
A Holonomic Sequence is a type of sequence satisfying a linear homogeneous
recurrence relation with Polynomial coefficients. Alternatively, A sequence
is Holonomic if and only if its generating function is a Holonomic Function.
"""
def __init__(self, recurrence, u0=[]):
self.recurrence = recurrence
if not isinstance(u0, list):
self.u0 = [u0]
else:
self.u0 = u0
if len(self.u0) == 0:
self._have_init_cond = False
else:
self._have_init_cond = True
self.n = recurrence.parent.base.gens[0]
def __repr__(self):
str_sol = 'HolonomicSequence(%s, %s)' % ((self.recurrence).__repr__(), sstr(self.n))
if not self._have_init_cond:
return str_sol
else:
cond_str = ''
seq_str = 0
for i in self.u0:
cond_str += ', u(%s) = %s' % (sstr(seq_str), sstr(i))
seq_str += 1
sol = str_sol + cond_str
return sol
__str__ = __repr__
def __eq__(self, other):
if self.recurrence == other.recurrence:
if self.n == other.n:
if self._have_init_cond and other._have_init_cond:
if self.u0 == other.u0:
return True
else:
return False
else:
return True
else:
return False
else:
return False
PK ]ZZZ�3U�� � sympy/integrals/__init__.py"""Integration functions that integrate a SymPy expression.
Examples
========
>>> from sympy import integrate, sin
>>> from sympy.abc import x
>>> integrate(1/x,x)
log(x)
>>> integrate(sin(x),x)
-cos(x)
"""
from .integrals import integrate, Integral, line_integrate
from .transforms import (mellin_transform, inverse_mellin_transform,
MellinTransform, InverseMellinTransform,
laplace_transform, inverse_laplace_transform,
laplace_correspondence, laplace_initial_conds,
LaplaceTransform, InverseLaplaceTransform,
fourier_transform, inverse_fourier_transform,
FourierTransform, InverseFourierTransform,
sine_transform, inverse_sine_transform,
SineTransform, InverseSineTransform,
cosine_transform, inverse_cosine_transform,
CosineTransform, InverseCosineTransform,
hankel_transform, inverse_hankel_transform,
HankelTransform, InverseHankelTransform)
from .singularityfunctions import singularityintegrate
__all__ = [
'integrate', 'Integral', 'line_integrate',
'mellin_transform', 'inverse_mellin_transform', 'MellinTransform',
'InverseMellinTransform', 'laplace_transform',
'inverse_laplace_transform', 'LaplaceTransform',
'laplace_correspondence', 'laplace_initial_conds',
'InverseLaplaceTransform', 'fourier_transform',
'inverse_fourier_transform', 'FourierTransform',
'InverseFourierTransform', 'sine_transform', 'inverse_sine_transform',
'SineTransform', 'InverseSineTransform', 'cosine_transform',
'inverse_cosine_transform', 'CosineTransform', 'InverseCosineTransform',
'hankel_transform', 'inverse_hankel_transform', 'HankelTransform',
'InverseHankelTransform',
'singularityintegrate',
]
PK ]ZZZ}`�P ! sympy/integrals/deltafunctions.pyfrom sympy.core.mul import Mul
from sympy.core.singleton import S
from sympy.core.sorting import default_sort_key
from sympy.functions import DiracDelta, Heaviside
from .integrals import Integral, integrate
def change_mul(node, x):
"""change_mul(node, x)
Rearranges the operands of a product, bringing to front any simple
DiracDelta expression.
Explanation
===========
If no simple DiracDelta expression was found, then all the DiracDelta
expressions are simplified (using DiracDelta.expand(diracdelta=True, wrt=x)).
Return: (dirac, new node)
Where:
o dirac is either a simple DiracDelta expression or None (if no simple
expression was found);
o new node is either a simplified DiracDelta expressions or None (if it
could not be simplified).
Examples
========
>>> from sympy import DiracDelta, cos
>>> from sympy.integrals.deltafunctions import change_mul
>>> from sympy.abc import x, y
>>> change_mul(x*y*DiracDelta(x)*cos(x), x)
(DiracDelta(x), x*y*cos(x))
>>> change_mul(x*y*DiracDelta(x**2 - 1)*cos(x), x)
(None, x*y*cos(x)*DiracDelta(x - 1)/2 + x*y*cos(x)*DiracDelta(x + 1)/2)
>>> change_mul(x*y*DiracDelta(cos(x))*cos(x), x)
(None, None)
See Also
========
sympy.functions.special.delta_functions.DiracDelta
deltaintegrate
"""
new_args = []
dirac = None
#Sorting is needed so that we consistently collapse the same delta;
#However, we must preserve the ordering of non-commutative terms
c, nc = node.args_cnc()
sorted_args = sorted(c, key=default_sort_key)
sorted_args.extend(nc)
for arg in sorted_args:
if arg.is_Pow and isinstance(arg.base, DiracDelta):
new_args.append(arg.func(arg.base, arg.exp - 1))
arg = arg.base
if dirac is None and (isinstance(arg, DiracDelta) and arg.is_simple(x)):
dirac = arg
else:
new_args.append(arg)
if not dirac: # there was no simple dirac
new_args = []
for arg in sorted_args:
if isinstance(arg, DiracDelta):
new_args.append(arg.expand(diracdelta=True, wrt=x))
elif arg.is_Pow and isinstance(arg.base, DiracDelta):
new_args.append(arg.func(arg.base.expand(diracdelta=True, wrt=x), arg.exp))
else:
new_args.append(arg)
if new_args != sorted_args:
nnode = Mul(*new_args).expand()
else: # if the node didn't change there is nothing to do
nnode = None
return (None, nnode)
return (dirac, Mul(*new_args))
def deltaintegrate(f, x):
"""
deltaintegrate(f, x)
Explanation
===========
The idea for integration is the following:
- If we are dealing with a DiracDelta expression, i.e. DiracDelta(g(x)),
we try to simplify it.
If we could simplify it, then we integrate the resulting expression.
We already know we can integrate a simplified expression, because only
simple DiracDelta expressions are involved.
If we couldn't simplify it, there are two cases:
1) The expression is a simple expression: we return the integral,
taking care if we are dealing with a Derivative or with a proper
DiracDelta.
2) The expression is not simple (i.e. DiracDelta(cos(x))): we can do
nothing at all.
- If the node is a multiplication node having a DiracDelta term:
First we expand it.
If the expansion did work, then we try to integrate the expansion.
If not, we try to extract a simple DiracDelta term, then we have two
cases:
1) We have a simple DiracDelta term, so we return the integral.
2) We didn't have a simple term, but we do have an expression with
simplified DiracDelta terms, so we integrate this expression.
Examples
========
>>> from sympy.abc import x, y, z
>>> from sympy.integrals.deltafunctions import deltaintegrate
>>> from sympy import sin, cos, DiracDelta
>>> deltaintegrate(x*sin(x)*cos(x)*DiracDelta(x - 1), x)
sin(1)*cos(1)*Heaviside(x - 1)
>>> deltaintegrate(y**2*DiracDelta(x - z)*DiracDelta(y - z), y)
z**2*DiracDelta(x - z)*Heaviside(y - z)
See Also
========
sympy.functions.special.delta_functions.DiracDelta
sympy.integrals.integrals.Integral
"""
if not f.has(DiracDelta):
return None
# g(x) = DiracDelta(h(x))
if f.func == DiracDelta:
h = f.expand(diracdelta=True, wrt=x)
if h == f: # can't simplify the expression
#FIXME: the second term tells whether is DeltaDirac or Derivative
#For integrating derivatives of DiracDelta we need the chain rule
if f.is_simple(x):
if (len(f.args) <= 1 or f.args[1] == 0):
return Heaviside(f.args[0])
else:
return (DiracDelta(f.args[0], f.args[1] - 1) /
f.args[0].as_poly().LC())
else: # let's try to integrate the simplified expression
fh = integrate(h, x)
return fh
elif f.is_Mul or f.is_Pow: # g(x) = a*b*c*f(DiracDelta(h(x)))*d*e
g = f.expand()
if f != g: # the expansion worked
fh = integrate(g, x)
if fh is not None and not isinstance(fh, Integral):
return fh
else:
# no expansion performed, try to extract a simple DiracDelta term
deltaterm, rest_mult = change_mul(f, x)
if not deltaterm:
if rest_mult:
fh = integrate(rest_mult, x)
return fh
else:
from sympy.solvers import solve
deltaterm = deltaterm.expand(diracdelta=True, wrt=x)
if deltaterm.is_Mul: # Take out any extracted factors
deltaterm, rest_mult_2 = change_mul(deltaterm, x)
rest_mult = rest_mult*rest_mult_2
point = solve(deltaterm.args[0], x)[0]
# Return the largest hyperreal term left after
# repeated integration by parts. For example,
#
# integrate(y*DiracDelta(x, 1),x) == y*DiracDelta(x,0), not 0
#
# This is so Integral(y*DiracDelta(x).diff(x),x).doit()
# will return y*DiracDelta(x) instead of 0 or DiracDelta(x),
# both of which are correct everywhere the value is defined
# but give wrong answers for nested integration.
n = (0 if len(deltaterm.args)==1 else deltaterm.args[1])
m = 0
while n >= 0:
r = S.NegativeOne**n*rest_mult.diff(x, n).subs(x, point)
if r.is_zero:
n -= 1
m += 1
else:
if m == 0:
return r*Heaviside(x - point)
else:
return r*DiracDelta(x,m-1)
# In some very weak sense, x=0 is still a singularity,
# but we hope will not be of any practical consequence.
return S.Zero
return None
PK ]ZZZ.�T�Rh Rh sympy/integrals/heurisch.pyfrom __future__ import annotations
from collections import defaultdict
from functools import reduce
from itertools import permutations
from sympy.core.add import Add
from sympy.core.basic import Basic
from sympy.core.mul import Mul
from sympy.core.symbol import Wild, Dummy, Symbol
from sympy.core.basic import sympify
from sympy.core.numbers import Rational, pi, I
from sympy.core.relational import Eq, Ne
from sympy.core.singleton import S
from sympy.core.sorting import ordered
from sympy.core.traversal import iterfreeargs
from sympy.functions import exp, sin, cos, tan, cot, asin, atan
from sympy.functions import log, sinh, cosh, tanh, coth, asinh
from sympy.functions import sqrt, erf, erfi, li, Ei
from sympy.functions import besselj, bessely, besseli, besselk
from sympy.functions import hankel1, hankel2, jn, yn
from sympy.functions.elementary.complexes import Abs, re, im, sign, arg
from sympy.functions.elementary.exponential import LambertW
from sympy.functions.elementary.integers import floor, ceiling
from sympy.functions.elementary.piecewise import Piecewise
from sympy.functions.special.delta_functions import Heaviside, DiracDelta
from sympy.simplify.radsimp import collect
from sympy.logic.boolalg import And, Or
from sympy.utilities.iterables import uniq
from sympy.polys import quo, gcd, lcm, factor_list, cancel, PolynomialError
from sympy.polys.monomials import itermonomials
from sympy.polys.polyroots import root_factors
from sympy.polys.rings import PolyRing
from sympy.polys.solvers import solve_lin_sys
from sympy.polys.constructor import construct_domain
from sympy.integrals.integrals import integrate
def components(f, x):
"""
Returns a set of all functional components of the given expression
which includes symbols, function applications and compositions and
non-integer powers. Fractional powers are collected with
minimal, positive exponents.
Examples
========
>>> from sympy import cos, sin
>>> from sympy.abc import x
>>> from sympy.integrals.heurisch import components
>>> components(sin(x)*cos(x)**2, x)
{x, sin(x), cos(x)}
See Also
========
heurisch
"""
result = set()
if f.has_free(x):
if f.is_symbol and f.is_commutative:
result.add(f)
elif f.is_Function or f.is_Derivative:
for g in f.args:
result |= components(g, x)
result.add(f)
elif f.is_Pow:
result |= components(f.base, x)
if not f.exp.is_Integer:
if f.exp.is_Rational:
result.add(f.base**Rational(1, f.exp.q))
else:
result |= components(f.exp, x) | {f}
else:
for g in f.args:
result |= components(g, x)
return result
# name -> [] of symbols
_symbols_cache: dict[str, list[Dummy]] = {}
# NB @cacheit is not convenient here
def _symbols(name, n):
"""get vector of symbols local to this module"""
try:
lsyms = _symbols_cache[name]
except KeyError:
lsyms = []
_symbols_cache[name] = lsyms
while len(lsyms) < n:
lsyms.append( Dummy('%s%i' % (name, len(lsyms))) )
return lsyms[:n]
def heurisch_wrapper(f, x, rewrite=False, hints=None, mappings=None, retries=3,
degree_offset=0, unnecessary_permutations=None,
_try_heurisch=None):
"""
A wrapper around the heurisch integration algorithm.
Explanation
===========
This method takes the result from heurisch and checks for poles in the
denominator. For each of these poles, the integral is reevaluated, and
the final integration result is given in terms of a Piecewise.
Examples
========
>>> from sympy import cos, symbols
>>> from sympy.integrals.heurisch import heurisch, heurisch_wrapper
>>> n, x = symbols('n x')
>>> heurisch(cos(n*x), x)
sin(n*x)/n
>>> heurisch_wrapper(cos(n*x), x)
Piecewise((sin(n*x)/n, Ne(n, 0)), (x, True))
See Also
========
heurisch
"""
from sympy.solvers.solvers import solve, denoms
f = sympify(f)
if not f.has_free(x):
return f*x
res = heurisch(f, x, rewrite, hints, mappings, retries, degree_offset,
unnecessary_permutations, _try_heurisch)
if not isinstance(res, Basic):
return res
# We consider each denominator in the expression, and try to find
# cases where one or more symbolic denominator might be zero. The
# conditions for these cases are stored in the list slns.
#
# Since denoms returns a set we use ordered. This is important because the
# ordering of slns determines the order of the resulting Piecewise so we
# need a deterministic order here to make the output deterministic.
slns = []
for d in ordered(denoms(res)):
try:
slns += solve([d], dict=True, exclude=(x,))
except NotImplementedError:
pass
if not slns:
return res
slns = list(uniq(slns))
# Remove the solutions corresponding to poles in the original expression.
slns0 = []
for d in denoms(f):
try:
slns0 += solve([d], dict=True, exclude=(x,))
except NotImplementedError:
pass
slns = [s for s in slns if s not in slns0]
if not slns:
return res
if len(slns) > 1:
eqs = []
for sub_dict in slns:
eqs.extend([Eq(key, value) for key, value in sub_dict.items()])
slns = solve(eqs, dict=True, exclude=(x,)) + slns
# For each case listed in the list slns, we reevaluate the integral.
pairs = []
for sub_dict in slns:
expr = heurisch(f.subs(sub_dict), x, rewrite, hints, mappings, retries,
degree_offset, unnecessary_permutations,
_try_heurisch)
cond = And(*[Eq(key, value) for key, value in sub_dict.items()])
generic = Or(*[Ne(key, value) for key, value in sub_dict.items()])
if expr is None:
expr = integrate(f.subs(sub_dict),x)
pairs.append((expr, cond))
# If there is one condition, put the generic case first. Otherwise,
# doing so may lead to longer Piecewise formulas
if len(pairs) == 1:
pairs = [(heurisch(f, x, rewrite, hints, mappings, retries,
degree_offset, unnecessary_permutations,
_try_heurisch),
generic),
(pairs[0][0], True)]
else:
pairs.append((heurisch(f, x, rewrite, hints, mappings, retries,
degree_offset, unnecessary_permutations,
_try_heurisch),
True))
return Piecewise(*pairs)
class BesselTable:
"""
Derivatives of Bessel functions of orders n and n-1
in terms of each other.
See the docstring of DiffCache.
"""
def __init__(self):
self.table = {}
self.n = Dummy('n')
self.z = Dummy('z')
self._create_table()
def _create_table(t):
table, n, z = t.table, t.n, t.z
for f in (besselj, bessely, hankel1, hankel2):
table[f] = (f(n-1, z) - n*f(n, z)/z,
(n-1)*f(n-1, z)/z - f(n, z))
f = besseli
table[f] = (f(n-1, z) - n*f(n, z)/z,
(n-1)*f(n-1, z)/z + f(n, z))
f = besselk
table[f] = (-f(n-1, z) - n*f(n, z)/z,
(n-1)*f(n-1, z)/z - f(n, z))
for f in (jn, yn):
table[f] = (f(n-1, z) - (n+1)*f(n, z)/z,
(n-1)*f(n-1, z)/z - f(n, z))
def diffs(t, f, n, z):
if f in t.table:
diff0, diff1 = t.table[f]
repl = [(t.n, n), (t.z, z)]
return (diff0.subs(repl), diff1.subs(repl))
def has(t, f):
return f in t.table
_bessel_table = None
class DiffCache:
"""
Store for derivatives of expressions.
Explanation
===========
The standard form of the derivative of a Bessel function of order n
contains two Bessel functions of orders n-1 and n+1, respectively.
Such forms cannot be used in parallel Risch algorithm, because
there is a linear recurrence relation between the three functions
while the algorithm expects that functions and derivatives are
represented in terms of algebraically independent transcendentals.
The solution is to take two of the functions, e.g., those of orders
n and n-1, and to express the derivatives in terms of the pair.
To guarantee that the proper form is used the two derivatives are
cached as soon as one is encountered.
Derivatives of other functions are also cached at no extra cost.
All derivatives are with respect to the same variable `x`.
"""
def __init__(self, x):
self.cache = {}
self.x = x
global _bessel_table
if not _bessel_table:
_bessel_table = BesselTable()
def get_diff(self, f):
cache = self.cache
if f in cache:
pass
elif (not hasattr(f, 'func') or
not _bessel_table.has(f.func)):
cache[f] = cancel(f.diff(self.x))
else:
n, z = f.args
d0, d1 = _bessel_table.diffs(f.func, n, z)
dz = self.get_diff(z)
cache[f] = d0*dz
cache[f.func(n-1, z)] = d1*dz
return cache[f]
def heurisch(f, x, rewrite=False, hints=None, mappings=None, retries=3,
degree_offset=0, unnecessary_permutations=None,
_try_heurisch=None):
"""
Compute indefinite integral using heuristic Risch algorithm.
Explanation
===========
This is a heuristic approach to indefinite integration in finite
terms using the extended heuristic (parallel) Risch algorithm, based
on Manuel Bronstein's "Poor Man's Integrator".
The algorithm supports various classes of functions including
transcendental elementary or special functions like Airy,
Bessel, Whittaker and Lambert.
Note that this algorithm is not a decision procedure. If it isn't
able to compute the antiderivative for a given function, then this is
not a proof that such a functions does not exist. One should use
recursive Risch algorithm in such case. It's an open question if
this algorithm can be made a full decision procedure.
This is an internal integrator procedure. You should use top level
'integrate' function in most cases, as this procedure needs some
preprocessing steps and otherwise may fail.
Specification
=============
heurisch(f, x, rewrite=False, hints=None)
where
f : expression
x : symbol
rewrite -> force rewrite 'f' in terms of 'tan' and 'tanh'
hints -> a list of functions that may appear in anti-derivate
- hints = None --> no suggestions at all
- hints = [ ] --> try to figure out
- hints = [f1, ..., fn] --> we know better
Examples
========
>>> from sympy import tan
>>> from sympy.integrals.heurisch import heurisch
>>> from sympy.abc import x, y
>>> heurisch(y*tan(x), x)
y*log(tan(x)**2 + 1)/2
See Manuel Bronstein's "Poor Man's Integrator":
References
==========
.. [1] https://www-sop.inria.fr/cafe/Manuel.Bronstein/pmint/index.html
For more information on the implemented algorithm refer to:
.. [2] K. Geddes, L. Stefanus, On the Risch-Norman Integration
Method and its Implementation in Maple, Proceedings of
ISSAC'89, ACM Press, 212-217.
.. [3] J. H. Davenport, On the Parallel Risch Algorithm (I),
Proceedings of EUROCAM'82, LNCS 144, Springer, 144-157.
.. [4] J. H. Davenport, On the Parallel Risch Algorithm (III):
Use of Tangents, SIGSAM Bulletin 16 (1982), 3-6.
.. [5] J. H. Davenport, B. M. Trager, On the Parallel Risch
Algorithm (II), ACM Transactions on Mathematical
Software 11 (1985), 356-362.
See Also
========
sympy.integrals.integrals.Integral.doit
sympy.integrals.integrals.Integral
sympy.integrals.heurisch.components
"""
f = sympify(f)
# There are some functions that Heurisch cannot currently handle,
# so do not even try.
# Set _try_heurisch=True to skip this check
if _try_heurisch is not True:
if f.has(Abs, re, im, sign, Heaviside, DiracDelta, floor, ceiling, arg):
return
if not f.has_free(x):
return f*x
if not f.is_Add:
indep, f = f.as_independent(x)
else:
indep = S.One
rewritables = {
(sin, cos, cot): tan,
(sinh, cosh, coth): tanh,
}
if rewrite:
for candidates, rule in rewritables.items():
f = f.rewrite(candidates, rule)
else:
for candidates in rewritables.keys():
if f.has(*candidates):
break
else:
rewrite = True
terms = components(f, x)
dcache = DiffCache(x)
if hints is not None:
if not hints:
a = Wild('a', exclude=[x])
b = Wild('b', exclude=[x])
c = Wild('c', exclude=[x])
for g in set(terms): # using copy of terms
if g.is_Function:
if isinstance(g, li):
M = g.args[0].match(a*x**b)
if M is not None:
terms.add( x*(li(M[a]*x**M[b]) - (M[a]*x**M[b])**(-1/M[b])*Ei((M[b]+1)*log(M[a]*x**M[b])/M[b])) )
#terms.add( x*(li(M[a]*x**M[b]) - (x**M[b])**(-1/M[b])*Ei((M[b]+1)*log(M[a]*x**M[b])/M[b])) )
#terms.add( x*(li(M[a]*x**M[b]) - x*Ei((M[b]+1)*log(M[a]*x**M[b])/M[b])) )
#terms.add( li(M[a]*x**M[b]) - Ei((M[b]+1)*log(M[a]*x**M[b])/M[b]) )
elif isinstance(g, exp):
M = g.args[0].match(a*x**2)
if M is not None:
if M[a].is_positive:
terms.add(erfi(sqrt(M[a])*x))
else: # M[a].is_negative or unknown
terms.add(erf(sqrt(-M[a])*x))
M = g.args[0].match(a*x**2 + b*x + c)
if M is not None:
if M[a].is_positive:
terms.add(sqrt(pi/4*(-M[a]))*exp(M[c] - M[b]**2/(4*M[a]))*
erfi(sqrt(M[a])*x + M[b]/(2*sqrt(M[a]))))
elif M[a].is_negative:
terms.add(sqrt(pi/4*(-M[a]))*exp(M[c] - M[b]**2/(4*M[a]))*
erf(sqrt(-M[a])*x - M[b]/(2*sqrt(-M[a]))))
M = g.args[0].match(a*log(x)**2)
if M is not None:
if M[a].is_positive:
terms.add(erfi(sqrt(M[a])*log(x) + 1/(2*sqrt(M[a]))))
if M[a].is_negative:
terms.add(erf(sqrt(-M[a])*log(x) - 1/(2*sqrt(-M[a]))))
elif g.is_Pow:
if g.exp.is_Rational and g.exp.q == 2:
M = g.base.match(a*x**2 + b)
if M is not None and M[b].is_positive:
if M[a].is_positive:
terms.add(asinh(sqrt(M[a]/M[b])*x))
elif M[a].is_negative:
terms.add(asin(sqrt(-M[a]/M[b])*x))
M = g.base.match(a*x**2 - b)
if M is not None and M[b].is_positive:
if M[a].is_positive:
dF = 1/sqrt(M[a]*x**2 - M[b])
F = log(2*sqrt(M[a])*sqrt(M[a]*x**2 - M[b]) + 2*M[a]*x)/sqrt(M[a])
dcache.cache[F] = dF # hack: F.diff(x) doesn't automatically simplify to f
terms.add(F)
elif M[a].is_negative:
terms.add(-M[b]/2*sqrt(-M[a])*
atan(sqrt(-M[a])*x/sqrt(M[a]*x**2 - M[b])))
else:
terms |= set(hints)
for g in set(terms): # using copy of terms
terms |= components(dcache.get_diff(g), x)
# XXX: The commented line below makes heurisch more deterministic wrt
# PYTHONHASHSEED and the iteration order of sets. There are other places
# where sets are iterated over but this one is possibly the most important.
# Theoretically the order here should not matter but different orderings
# can expose potential bugs in the different code paths so potentially it
# is better to keep the non-determinism.
#
# terms = list(ordered(terms))
# TODO: caching is significant factor for why permutations work at all. Change this.
V = _symbols('x', len(terms))
# sort mapping expressions from largest to smallest (last is always x).
mapping = list(reversed(list(zip(*ordered( #
[(a[0].as_independent(x)[1], a) for a in zip(terms, V)])))[1])) #
rev_mapping = {v: k for k, v in mapping} #
if mappings is None: #
# optimizing the number of permutations of mapping #
assert mapping[-1][0] == x # if not, find it and correct this comment
unnecessary_permutations = [mapping.pop(-1)]
# permute types of objects
types = defaultdict(list)
for i in mapping:
e, _ = i
types[type(e)].append(i)
mapping = [types[i] for i in types]
def _iter_mappings():
for i in permutations(mapping):
# make the expression of a given type be ordered
yield [j for i in i for j in ordered(i)]
mappings = _iter_mappings()
else:
unnecessary_permutations = unnecessary_permutations or []
def _substitute(expr):
return expr.subs(mapping)
for mapping in mappings:
mapping = list(mapping)
mapping = mapping + unnecessary_permutations
diffs = [ _substitute(dcache.get_diff(g)) for g in terms ]
denoms = [ g.as_numer_denom()[1] for g in diffs ]
if all(h.is_polynomial(*V) for h in denoms) and _substitute(f).is_rational_function(*V):
denom = reduce(lambda p, q: lcm(p, q, *V), denoms)
break
else:
if not rewrite:
result = heurisch(f, x, rewrite=True, hints=hints,
unnecessary_permutations=unnecessary_permutations)
if result is not None:
return indep*result
return None
numers = [ cancel(denom*g) for g in diffs ]
def _derivation(h):
return Add(*[ d * h.diff(v) for d, v in zip(numers, V) ])
def _deflation(p):
for y in V:
if not p.has(y):
continue
if _derivation(p) is not S.Zero:
c, q = p.as_poly(y).primitive()
return _deflation(c)*gcd(q, q.diff(y)).as_expr()
return p
def _splitter(p):
for y in V:
if not p.has(y):
continue
if _derivation(y) is not S.Zero:
c, q = p.as_poly(y).primitive()
q = q.as_expr()
h = gcd(q, _derivation(q), y)
s = quo(h, gcd(q, q.diff(y), y), y)
c_split = _splitter(c)
if s.as_poly(y).degree() == 0:
return (c_split[0], q * c_split[1])
q_split = _splitter(cancel(q / s))
return (c_split[0]*q_split[0]*s, c_split[1]*q_split[1])
return (S.One, p)
special = {}
for term in terms:
if term.is_Function:
if isinstance(term, tan):
special[1 + _substitute(term)**2] = False
elif isinstance(term, tanh):
special[1 + _substitute(term)] = False
special[1 - _substitute(term)] = False
elif isinstance(term, LambertW):
special[_substitute(term)] = True
F = _substitute(f)
P, Q = F.as_numer_denom()
u_split = _splitter(denom)
v_split = _splitter(Q)
polys = set(list(v_split) + [ u_split[0] ] + list(special.keys()))
s = u_split[0] * Mul(*[ k for k, v in special.items() if v ])
polified = [ p.as_poly(*V) for p in [s, P, Q] ]
if None in polified:
return None
#--- definitions for _integrate
a, b, c = [ p.total_degree() for p in polified ]
poly_denom = (s * v_split[0] * _deflation(v_split[1])).as_expr()
def _exponent(g):
if g.is_Pow:
if g.exp.is_Rational and g.exp.q != 1:
if g.exp.p > 0:
return g.exp.p + g.exp.q - 1
else:
return abs(g.exp.p + g.exp.q)
else:
return 1
elif not g.is_Atom and g.args:
return max(_exponent(h) for h in g.args)
else:
return 1
A, B = _exponent(f), a + max(b, c)
if A > 1 and B > 1:
monoms = tuple(ordered(itermonomials(V, A + B - 1 + degree_offset)))
else:
monoms = tuple(ordered(itermonomials(V, A + B + degree_offset)))
poly_coeffs = _symbols('A', len(monoms))
poly_part = Add(*[ poly_coeffs[i]*monomial
for i, monomial in enumerate(monoms) ])
reducibles = set()
for poly in ordered(polys):
coeff, factors = factor_list(poly, *V)
reducibles.add(coeff)
reducibles.update(fact for fact, mul in factors)
def _integrate(field=None):
atans = set()
pairs = set()
if field == 'Q':
irreducibles = set(reducibles)
else:
setV = set(V)
irreducibles = set()
for poly in ordered(reducibles):
zV = setV & set(iterfreeargs(poly))
for z in ordered(zV):
s = set(root_factors(poly, z, filter=field))
irreducibles |= s
break
log_part, atan_part = [], []
for poly in ordered(irreducibles):
m = collect(poly, I, evaluate=False)
y = m.get(I, S.Zero)
if y:
x = m.get(S.One, S.Zero)
if x.has(I) or y.has(I):
continue # nontrivial x + I*y
pairs.add((x, y))
irreducibles.remove(poly)
while pairs:
x, y = pairs.pop()
if (x, -y) in pairs:
pairs.remove((x, -y))
# Choosing b with no minus sign
if y.could_extract_minus_sign():
y = -y
irreducibles.add(x*x + y*y)
atans.add(atan(x/y))
else:
irreducibles.add(x + I*y)
B = _symbols('B', len(irreducibles))
C = _symbols('C', len(atans))
# Note: the ordering matters here
for poly, b in reversed(list(zip(ordered(irreducibles), B))):
if poly.has(*V):
poly_coeffs.append(b)
log_part.append(b * log(poly))
for poly, c in reversed(list(zip(ordered(atans), C))):
if poly.has(*V):
poly_coeffs.append(c)
atan_part.append(c * poly)
# TODO: Currently it's better to use symbolic expressions here instead
# of rational functions, because it's simpler and FracElement doesn't
# give big speed improvement yet. This is because cancellation is slow
# due to slow polynomial GCD algorithms. If this gets improved then
# revise this code.
candidate = poly_part/poly_denom + Add(*log_part) + Add(*atan_part)
h = F - _derivation(candidate) / denom
raw_numer = h.as_numer_denom()[0]
# Rewrite raw_numer as a polynomial in K[coeffs][V] where K is a field
# that we have to determine. We can't use simply atoms() because log(3),
# sqrt(y) and similar expressions can appear, leading to non-trivial
# domains.
syms = set(poly_coeffs) | set(V)
non_syms = set()
def find_non_syms(expr):
if expr.is_Integer or expr.is_Rational:
pass # ignore trivial numbers
elif expr in syms:
pass # ignore variables
elif not expr.has_free(*syms):
non_syms.add(expr)
elif expr.is_Add or expr.is_Mul or expr.is_Pow:
list(map(find_non_syms, expr.args))
else:
# TODO: Non-polynomial expression. This should have been
# filtered out at an earlier stage.
raise PolynomialError
try:
find_non_syms(raw_numer)
except PolynomialError:
return None
else:
ground, _ = construct_domain(non_syms, field=True)
coeff_ring = PolyRing(poly_coeffs, ground)
ring = PolyRing(V, coeff_ring)
try:
numer = ring.from_expr(raw_numer)
except ValueError:
raise PolynomialError
solution = solve_lin_sys(numer.coeffs(), coeff_ring, _raw=False)
if solution is None:
return None
else:
return candidate.xreplace(solution).xreplace(
dict(zip(poly_coeffs, [S.Zero]*len(poly_coeffs))))
if all(isinstance(_, Symbol) for _ in V):
more_free = F.free_symbols - set(V)
else:
Fd = F.as_dummy()
more_free = Fd.xreplace(dict(zip(V, (Dummy() for _ in V)))
).free_symbols & Fd.free_symbols
if not more_free:
# all free generators are identified in V
solution = _integrate('Q')
if solution is None:
solution = _integrate()
else:
solution = _integrate()
if solution is not None:
antideriv = solution.subs(rev_mapping)
antideriv = cancel(antideriv).expand()
if antideriv.is_Add:
antideriv = antideriv.as_independent(x)[1]
return indep*antideriv
else:
if retries >= 0:
result = heurisch(f, x, mappings=mappings, rewrite=rewrite, hints=hints, retries=retries - 1, unnecessary_permutations=unnecessary_permutations)
if result is not None:
return indep*result
return None
PK ]ZZZ��g�d� d� sympy/integrals/integrals.pyfrom typing import Tuple as tTuple
from sympy.concrete.expr_with_limits import AddWithLimits
from sympy.core.add import Add
from sympy.core.basic import Basic
from sympy.core.containers import Tuple
from sympy.core.expr import Expr
from sympy.core.exprtools import factor_terms
from sympy.core.function import diff
from sympy.core.logic import fuzzy_bool
from sympy.core.mul import Mul
from sympy.core.numbers import oo, pi
from sympy.core.relational import Ne
from sympy.core.singleton import S
from sympy.core.symbol import (Dummy, Symbol, Wild)
from sympy.core.sympify import sympify
from sympy.functions import Piecewise, sqrt, piecewise_fold, tan, cot, atan
from sympy.functions.elementary.exponential import log
from sympy.functions.elementary.integers import floor
from sympy.functions.elementary.complexes import Abs, sign
from sympy.functions.elementary.miscellaneous import Min, Max
from sympy.functions.special.singularity_functions import Heaviside
from .rationaltools import ratint
from sympy.matrices import MatrixBase
from sympy.polys import Poly, PolynomialError
from sympy.series.formal import FormalPowerSeries
from sympy.series.limits import limit
from sympy.series.order import Order
from sympy.tensor.functions import shape
from sympy.utilities.exceptions import sympy_deprecation_warning
from sympy.utilities.iterables import is_sequence
from sympy.utilities.misc import filldedent
class Integral(AddWithLimits):
"""Represents unevaluated integral."""
__slots__ = ()
args: tTuple[Expr, Tuple]
def __new__(cls, function, *symbols, **assumptions):
"""Create an unevaluated integral.
Explanation
===========
Arguments are an integrand followed by one or more limits.
If no limits are given and there is only one free symbol in the
expression, that symbol will be used, otherwise an error will be
raised.
>>> from sympy import Integral
>>> from sympy.abc import x, y
>>> Integral(x)
Integral(x, x)
>>> Integral(y)
Integral(y, y)
When limits are provided, they are interpreted as follows (using
``x`` as though it were the variable of integration):
(x,) or x - indefinite integral
(x, a) - "evaluate at" integral is an abstract antiderivative
(x, a, b) - definite integral
The ``as_dummy`` method can be used to see which symbols cannot be
targeted by subs: those with a prepended underscore cannot be
changed with ``subs``. (Also, the integration variables themselves --
the first element of a limit -- can never be changed by subs.)
>>> i = Integral(x, x)
>>> at = Integral(x, (x, x))
>>> i.as_dummy()
Integral(x, x)
>>> at.as_dummy()
Integral(_0, (_0, x))
"""
#This will help other classes define their own definitions
#of behaviour with Integral.
if hasattr(function, '_eval_Integral'):
return function._eval_Integral(*symbols, **assumptions)
if isinstance(function, Poly):
sympy_deprecation_warning(
"""
integrate(Poly) and Integral(Poly) are deprecated. Instead,
use the Poly.integrate() method, or convert the Poly to an
Expr first with the Poly.as_expr() method.
""",
deprecated_since_version="1.6",
active_deprecations_target="deprecated-integrate-poly")
obj = AddWithLimits.__new__(cls, function, *symbols, **assumptions)
return obj
def __getnewargs__(self):
return (self.function,) + tuple([tuple(xab) for xab in self.limits])
@property
def free_symbols(self):
"""
This method returns the symbols that will exist when the
integral is evaluated. This is useful if one is trying to
determine whether an integral depends on a certain
symbol or not.
Examples
========
>>> from sympy import Integral
>>> from sympy.abc import x, y
>>> Integral(x, (x, y, 1)).free_symbols
{y}
See Also
========
sympy.concrete.expr_with_limits.ExprWithLimits.function
sympy.concrete.expr_with_limits.ExprWithLimits.limits
sympy.concrete.expr_with_limits.ExprWithLimits.variables
"""
return super().free_symbols
def _eval_is_zero(self):
# This is a very naive and quick test, not intended to do the integral to
# answer whether it is zero or not, e.g. Integral(sin(x), (x, 0, 2*pi))
# is zero but this routine should return None for that case. But, like
# Mul, there are trivial situations for which the integral will be
# zero so we check for those.
if self.function.is_zero:
return True
got_none = False
for l in self.limits:
if len(l) == 3:
z = (l[1] == l[2]) or (l[1] - l[2]).is_zero
if z:
return True
elif z is None:
got_none = True
free = self.function.free_symbols
for xab in self.limits:
if len(xab) == 1:
free.add(xab[0])
continue
if len(xab) == 2 and xab[0] not in free:
if xab[1].is_zero:
return True
elif xab[1].is_zero is None:
got_none = True
# take integration symbol out of free since it will be replaced
# with the free symbols in the limits
free.discard(xab[0])
# add in the new symbols
for i in xab[1:]:
free.update(i.free_symbols)
if self.function.is_zero is False and got_none is False:
return False
def transform(self, x, u):
r"""
Performs a change of variables from `x` to `u` using the relationship
given by `x` and `u` which will define the transformations `f` and `F`
(which are inverses of each other) as follows:
1) If `x` is a Symbol (which is a variable of integration) then `u`
will be interpreted as some function, f(u), with inverse F(u).
This, in effect, just makes the substitution of x with f(x).
2) If `u` is a Symbol then `x` will be interpreted as some function,
F(x), with inverse f(u). This is commonly referred to as
u-substitution.
Once f and F have been identified, the transformation is made as
follows:
.. math:: \int_a^b x \mathrm{d}x \rightarrow \int_{F(a)}^{F(b)} f(x)
\frac{\mathrm{d}}{\mathrm{d}x}
where `F(x)` is the inverse of `f(x)` and the limits and integrand have
been corrected so as to retain the same value after integration.
Notes
=====
The mappings, F(x) or f(u), must lead to a unique integral. Linear
or rational linear expression, ``2*x``, ``1/x`` and ``sqrt(x)``, will
always work; quadratic expressions like ``x**2 - 1`` are acceptable
as long as the resulting integrand does not depend on the sign of
the solutions (see examples).
The integral will be returned unchanged if ``x`` is not a variable of
integration.
``x`` must be (or contain) only one of of the integration variables. If
``u`` has more than one free symbol then it should be sent as a tuple
(``u``, ``uvar``) where ``uvar`` identifies which variable is replacing
the integration variable.
XXX can it contain another integration variable?
Examples
========
>>> from sympy.abc import a, x, u
>>> from sympy import Integral, cos, sqrt
>>> i = Integral(x*cos(x**2 - 1), (x, 0, 1))
transform can change the variable of integration
>>> i.transform(x, u)
Integral(u*cos(u**2 - 1), (u, 0, 1))
transform can perform u-substitution as long as a unique
integrand is obtained:
>>> ui = i.transform(x**2 - 1, u)
>>> ui
Integral(cos(u)/2, (u, -1, 0))
This attempt fails because x = +/-sqrt(u + 1) and the
sign does not cancel out of the integrand:
>>> Integral(cos(x**2 - 1), (x, 0, 1)).transform(x**2 - 1, u)
Traceback (most recent call last):
...
ValueError:
The mapping between F(x) and f(u) did not give a unique integrand.
transform can do a substitution. Here, the previous
result is transformed back into the original expression
using "u-substitution":
>>> ui.transform(sqrt(u + 1), x) == i
True
We can accomplish the same with a regular substitution:
>>> ui.transform(u, x**2 - 1) == i
True
If the `x` does not contain a symbol of integration then
the integral will be returned unchanged. Integral `i` does
not have an integration variable `a` so no change is made:
>>> i.transform(a, x) == i
True
When `u` has more than one free symbol the symbol that is
replacing `x` must be identified by passing `u` as a tuple:
>>> Integral(x, (x, 0, 1)).transform(x, (u + a, u))
Integral(a + u, (u, -a, 1 - a))
>>> Integral(x, (x, 0, 1)).transform(x, (u + a, a))
Integral(a + u, (a, -u, 1 - u))
See Also
========
sympy.concrete.expr_with_limits.ExprWithLimits.variables : Lists the integration variables
as_dummy : Replace integration variables with dummy ones
"""
d = Dummy('d')
xfree = x.free_symbols.intersection(self.variables)
if len(xfree) > 1:
raise ValueError(
'F(x) can only contain one of: %s' % self.variables)
xvar = xfree.pop() if xfree else d
if xvar not in self.variables:
return self
u = sympify(u)
if isinstance(u, Expr):
ufree = u.free_symbols
if len(ufree) == 0:
raise ValueError(filldedent('''
f(u) cannot be a constant'''))
if len(ufree) > 1:
raise ValueError(filldedent('''
When f(u) has more than one free symbol, the one replacing x
must be identified: pass f(u) as (f(u), u)'''))
uvar = ufree.pop()
else:
u, uvar = u
if uvar not in u.free_symbols:
raise ValueError(filldedent('''
Expecting a tuple (expr, symbol) where symbol identified
a free symbol in expr, but symbol is not in expr's free
symbols.'''))
if not isinstance(uvar, Symbol):
# This probably never evaluates to True
raise ValueError(filldedent('''
Expecting a tuple (expr, symbol) but didn't get
a symbol; got %s''' % uvar))
if x.is_Symbol and u.is_Symbol:
return self.xreplace({x: u})
if not x.is_Symbol and not u.is_Symbol:
raise ValueError('either x or u must be a symbol')
if uvar == xvar:
return self.transform(x, (u.subs(uvar, d), d)).xreplace({d: uvar})
if uvar in self.limits:
raise ValueError(filldedent('''
u must contain the same variable as in x
or a variable that is not already an integration variable'''))
from sympy.solvers.solvers import solve
if not x.is_Symbol:
F = [x.subs(xvar, d)]
soln = solve(u - x, xvar, check=False)
if not soln:
raise ValueError('no solution for solve(F(x) - f(u), x)')
f = [fi.subs(uvar, d) for fi in soln]
else:
f = [u.subs(uvar, d)]
from sympy.simplify.simplify import posify
pdiff, reps = posify(u - x)
puvar = uvar.subs([(v, k) for k, v in reps.items()])
soln = [s.subs(reps) for s in solve(pdiff, puvar)]
if not soln:
raise ValueError('no solution for solve(F(x) - f(u), u)')
F = [fi.subs(xvar, d) for fi in soln]
newfuncs = {(self.function.subs(xvar, fi)*fi.diff(d)
).subs(d, uvar) for fi in f}
if len(newfuncs) > 1:
raise ValueError(filldedent('''
The mapping between F(x) and f(u) did not give
a unique integrand.'''))
newfunc = newfuncs.pop()
def _calc_limit_1(F, a, b):
"""
replace d with a, using subs if possible, otherwise limit
where sign of b is considered
"""
wok = F.subs(d, a)
if wok is S.NaN or wok.is_finite is False and a.is_finite:
return limit(sign(b)*F, d, a)
return wok
def _calc_limit(a, b):
"""
replace d with a, using subs if possible, otherwise limit
where sign of b is considered
"""
avals = list({_calc_limit_1(Fi, a, b) for Fi in F})
if len(avals) > 1:
raise ValueError(filldedent('''
The mapping between F(x) and f(u) did not
give a unique limit.'''))
return avals[0]
newlimits = []
for xab in self.limits:
sym = xab[0]
if sym == xvar:
if len(xab) == 3:
a, b = xab[1:]
a, b = _calc_limit(a, b), _calc_limit(b, a)
if fuzzy_bool(a - b > 0):
a, b = b, a
newfunc = -newfunc
newlimits.append((uvar, a, b))
elif len(xab) == 2:
a = _calc_limit(xab[1], 1)
newlimits.append((uvar, a))
else:
newlimits.append(uvar)
else:
newlimits.append(xab)
return self.func(newfunc, *newlimits)
def doit(self, **hints):
"""
Perform the integration using any hints given.
Examples
========
>>> from sympy import Piecewise, S
>>> from sympy.abc import x, t
>>> p = x**2 + Piecewise((0, x/t < 0), (1, True))
>>> p.integrate((t, S(4)/5, 1), (x, -1, 1))
1/3
See Also
========
sympy.integrals.trigonometry.trigintegrate
sympy.integrals.heurisch.heurisch
sympy.integrals.rationaltools.ratint
as_sum : Approximate the integral using a sum
"""
if not hints.get('integrals', True):
return self
deep = hints.get('deep', True)
meijerg = hints.get('meijerg', None)
conds = hints.get('conds', 'piecewise')
risch = hints.get('risch', None)
heurisch = hints.get('heurisch', None)
manual = hints.get('manual', None)
if len(list(filter(None, (manual, meijerg, risch, heurisch)))) > 1:
raise ValueError("At most one of manual, meijerg, risch, heurisch can be True")
elif manual:
meijerg = risch = heurisch = False
elif meijerg:
manual = risch = heurisch = False
elif risch:
manual = meijerg = heurisch = False
elif heurisch:
manual = meijerg = risch = False
eval_kwargs = {"meijerg": meijerg, "risch": risch, "manual": manual, "heurisch": heurisch,
"conds": conds}
if conds not in ('separate', 'piecewise', 'none'):
raise ValueError('conds must be one of "separate", "piecewise", '
'"none", got: %s' % conds)
if risch and any(len(xab) > 1 for xab in self.limits):
raise ValueError('risch=True is only allowed for indefinite integrals.')
# check for the trivial zero
if self.is_zero:
return S.Zero
# hacks to handle integrals of
# nested summations
from sympy.concrete.summations import Sum
if isinstance(self.function, Sum):
if any(v in self.function.limits[0] for v in self.variables):
raise ValueError('Limit of the sum cannot be an integration variable.')
if any(l.is_infinite for l in self.function.limits[0][1:]):
return self
_i = self
_sum = self.function
return _sum.func(_i.func(_sum.function, *_i.limits).doit(), *_sum.limits).doit()
# now compute and check the function
function = self.function
# hack to use a consistent Heaviside(x, 1/2)
function = function.replace(
lambda x: isinstance(x, Heaviside) and x.args[1]*2 != 1,
lambda x: Heaviside(x.args[0]))
if deep:
function = function.doit(**hints)
if function.is_zero:
return S.Zero
# hacks to handle special cases
if isinstance(function, MatrixBase):
return function.applyfunc(
lambda f: self.func(f, *self.limits).doit(**hints))
if isinstance(function, FormalPowerSeries):
if len(self.limits) > 1:
raise NotImplementedError
xab = self.limits[0]
if len(xab) > 1:
return function.integrate(xab, **eval_kwargs)
else:
return function.integrate(xab[0], **eval_kwargs)
# There is no trivial answer and special handling
# is done so continue
# first make sure any definite limits have integration
# variables with matching assumptions
reps = {}
for xab in self.limits:
if len(xab) != 3:
# it makes sense to just make
# all x real but in practice with the
# current state of integration...this
# doesn't work out well
# x = xab[0]
# if x not in reps and not x.is_real:
# reps[x] = Dummy(real=True)
continue
x, a, b = xab
l = (a, b)
if all(i.is_nonnegative for i in l) and not x.is_nonnegative:
d = Dummy(positive=True)
elif all(i.is_nonpositive for i in l) and not x.is_nonpositive:
d = Dummy(negative=True)
elif all(i.is_real for i in l) and not x.is_real:
d = Dummy(real=True)
else:
d = None
if d:
reps[x] = d
if reps:
undo = {v: k for k, v in reps.items()}
did = self.xreplace(reps).doit(**hints)
if isinstance(did, tuple): # when separate=True
did = tuple([i.xreplace(undo) for i in did])
else:
did = did.xreplace(undo)
return did
# continue with existing assumptions
undone_limits = []
# ulj = free symbols of any undone limits' upper and lower limits
ulj = set()
for xab in self.limits:
# compute uli, the free symbols in the
# Upper and Lower limits of limit I
if len(xab) == 1:
uli = set(xab[:1])
elif len(xab) == 2:
uli = xab[1].free_symbols
elif len(xab) == 3:
uli = xab[1].free_symbols.union(xab[2].free_symbols)
# this integral can be done as long as there is no blocking
# limit that has been undone. An undone limit is blocking if
# it contains an integration variable that is in this limit's
# upper or lower free symbols or vice versa
if xab[0] in ulj or any(v[0] in uli for v in undone_limits):
undone_limits.append(xab)
ulj.update(uli)
function = self.func(*([function] + [xab]))
factored_function = function.factor()
if not isinstance(factored_function, Integral):
function = factored_function
continue
if function.has(Abs, sign) and (
(len(xab) < 3 and all(x.is_extended_real for x in xab)) or
(len(xab) == 3 and all(x.is_extended_real and not x.is_infinite for
x in xab[1:]))):
# some improper integrals are better off with Abs
xr = Dummy("xr", real=True)
function = (function.xreplace({xab[0]: xr})
.rewrite(Piecewise).xreplace({xr: xab[0]}))
elif function.has(Min, Max):
function = function.rewrite(Piecewise)
if (function.has(Piecewise) and
not isinstance(function, Piecewise)):
function = piecewise_fold(function)
if isinstance(function, Piecewise):
if len(xab) == 1:
antideriv = function._eval_integral(xab[0],
**eval_kwargs)
else:
antideriv = self._eval_integral(
function, xab[0], **eval_kwargs)
else:
# There are a number of tradeoffs in using the
# Meijer G method. It can sometimes be a lot faster
# than other methods, and sometimes slower. And
# there are certain types of integrals for which it
# is more likely to work than others. These
# heuristics are incorporated in deciding what
# integration methods to try, in what order. See the
# integrate() docstring for details.
def try_meijerg(function, xab):
ret = None
if len(xab) == 3 and meijerg is not False:
x, a, b = xab
try:
res = meijerint_definite(function, x, a, b)
except NotImplementedError:
_debug('NotImplementedError '
'from meijerint_definite')
res = None
if res is not None:
f, cond = res
if conds == 'piecewise':
u = self.func(function, (x, a, b))
# if Piecewise modifies cond too
# much it may not be recognized by
# _condsimp pattern matching so just
# turn off all evaluation
return Piecewise((f, cond), (u, True),
evaluate=False)
elif conds == 'separate':
if len(self.limits) != 1:
raise ValueError(filldedent('''
conds=separate not supported in
multiple integrals'''))
ret = f, cond
else:
ret = f
return ret
meijerg1 = meijerg
if (meijerg is not False and
len(xab) == 3 and xab[1].is_extended_real and xab[2].is_extended_real
and not function.is_Poly and
(xab[1].has(oo, -oo) or xab[2].has(oo, -oo))):
ret = try_meijerg(function, xab)
if ret is not None:
function = ret
continue
meijerg1 = False
# If the special meijerg code did not succeed in
# finding a definite integral, then the code using
# meijerint_indefinite will not either (it might
# find an antiderivative, but the answer is likely
# to be nonsensical). Thus if we are requested to
# only use Meijer G-function methods, we give up at
# this stage. Otherwise we just disable G-function
# methods.
if meijerg1 is False and meijerg is True:
antideriv = None
else:
antideriv = self._eval_integral(
function, xab[0], **eval_kwargs)
if antideriv is None and meijerg is True:
ret = try_meijerg(function, xab)
if ret is not None:
function = ret
continue
final = hints.get('final', True)
# dotit may be iterated but floor terms making atan and acot
# continuous should only be added in the final round
if (final and not isinstance(antideriv, Integral) and
antideriv is not None):
for atan_term in antideriv.atoms(atan):
atan_arg = atan_term.args[0]
# Checking `atan_arg` to be linear combination of `tan` or `cot`
for tan_part in atan_arg.atoms(tan):
x1 = Dummy('x1')
tan_exp1 = atan_arg.subs(tan_part, x1)
# The coefficient of `tan` should be constant
coeff = tan_exp1.diff(x1)
if x1 not in coeff.free_symbols:
a = tan_part.args[0]
antideriv = antideriv.subs(atan_term, Add(atan_term,
sign(coeff)*pi*floor((a-pi/2)/pi)))
for cot_part in atan_arg.atoms(cot):
x1 = Dummy('x1')
cot_exp1 = atan_arg.subs(cot_part, x1)
# The coefficient of `cot` should be constant
coeff = cot_exp1.diff(x1)
if x1 not in coeff.free_symbols:
a = cot_part.args[0]
antideriv = antideriv.subs(atan_term, Add(atan_term,
sign(coeff)*pi*floor((a)/pi)))
if antideriv is None:
undone_limits.append(xab)
function = self.func(*([function] + [xab])).factor()
factored_function = function.factor()
if not isinstance(factored_function, Integral):
function = factored_function
continue
else:
if len(xab) == 1:
function = antideriv
else:
if len(xab) == 3:
x, a, b = xab
elif len(xab) == 2:
x, b = xab
a = None
else:
raise NotImplementedError
if deep:
if isinstance(a, Basic):
a = a.doit(**hints)
if isinstance(b, Basic):
b = b.doit(**hints)
if antideriv.is_Poly:
gens = list(antideriv.gens)
gens.remove(x)
antideriv = antideriv.as_expr()
function = antideriv._eval_interval(x, a, b)
function = Poly(function, *gens)
else:
def is_indef_int(g, x):
return (isinstance(g, Integral) and
any(i == (x,) for i in g.limits))
def eval_factored(f, x, a, b):
# _eval_interval for integrals with
# (constant) factors
# a single indefinite integral is assumed
args = []
for g in Mul.make_args(f):
if is_indef_int(g, x):
args.append(g._eval_interval(x, a, b))
else:
args.append(g)
return Mul(*args)
integrals, others, piecewises = [], [], []
for f in Add.make_args(antideriv):
if any(is_indef_int(g, x)
for g in Mul.make_args(f)):
integrals.append(f)
elif any(isinstance(g, Piecewise)
for g in Mul.make_args(f)):
piecewises.append(piecewise_fold(f))
else:
others.append(f)
uneval = Add(*[eval_factored(f, x, a, b)
for f in integrals])
try:
evalued = Add(*others)._eval_interval(x, a, b)
evalued_pw = piecewise_fold(Add(*piecewises))._eval_interval(x, a, b)
function = uneval + evalued + evalued_pw
except NotImplementedError:
# This can happen if _eval_interval depends in a
# complicated way on limits that cannot be computed
undone_limits.append(xab)
function = self.func(*([function] + [xab]))
factored_function = function.factor()
if not isinstance(factored_function, Integral):
function = factored_function
return function
def _eval_derivative(self, sym):
"""Evaluate the derivative of the current Integral object by
differentiating under the integral sign [1], using the Fundamental
Theorem of Calculus [2] when possible.
Explanation
===========
Whenever an Integral is encountered that is equivalent to zero or
has an integrand that is independent of the variable of integration
those integrals are performed. All others are returned as Integral
instances which can be resolved with doit() (provided they are integrable).
References
==========
.. [1] https://en.wikipedia.org/wiki/Differentiation_under_the_integral_sign
.. [2] https://en.wikipedia.org/wiki/Fundamental_theorem_of_calculus
Examples
========
>>> from sympy import Integral
>>> from sympy.abc import x, y
>>> i = Integral(x + y, y, (y, 1, x))
>>> i.diff(x)
Integral(x + y, (y, x)) + Integral(1, y, (y, 1, x))
>>> i.doit().diff(x) == i.diff(x).doit()
True
>>> i.diff(y)
0
The previous must be true since there is no y in the evaluated integral:
>>> i.free_symbols
{x}
>>> i.doit()
2*x**3/3 - x/2 - 1/6
"""
# differentiate under the integral sign; we do not
# check for regularity conditions (TODO), see issue 4215
# get limits and the function
f, limits = self.function, list(self.limits)
# the order matters if variables of integration appear in the limits
# so work our way in from the outside to the inside.
limit = limits.pop(-1)
if len(limit) == 3:
x, a, b = limit
elif len(limit) == 2:
x, b = limit
a = None
else:
a = b = None
x = limit[0]
if limits: # f is the argument to an integral
f = self.func(f, *tuple(limits))
# assemble the pieces
def _do(f, ab):
dab_dsym = diff(ab, sym)
if not dab_dsym:
return S.Zero
if isinstance(f, Integral):
limits = [(x, x) if (len(l) == 1 and l[0] == x) else l
for l in f.limits]
f = self.func(f.function, *limits)
return f.subs(x, ab)*dab_dsym
rv = S.Zero
if b is not None:
rv += _do(f, b)
if a is not None:
rv -= _do(f, a)
if len(limit) == 1 and sym == x:
# the dummy variable *is* also the real-world variable
arg = f
rv += arg
else:
# the dummy variable might match sym but it's
# only a dummy and the actual variable is determined
# by the limits, so mask off the variable of integration
# while differentiating
u = Dummy('u')
arg = f.subs(x, u).diff(sym).subs(u, x)
if arg:
rv += self.func(arg, (x, a, b))
return rv
def _eval_integral(self, f, x, meijerg=None, risch=None, manual=None,
heurisch=None, conds='piecewise',final=None):
"""
Calculate the anti-derivative to the function f(x).
Explanation
===========
The following algorithms are applied (roughly in this order):
1. Simple heuristics (based on pattern matching and integral table):
- most frequently used functions (e.g. polynomials, products of
trig functions)
2. Integration of rational functions:
- A complete algorithm for integrating rational functions is
implemented (the Lazard-Rioboo-Trager algorithm). The algorithm
also uses the partial fraction decomposition algorithm
implemented in apart() as a preprocessor to make this process
faster. Note that the integral of a rational function is always
elementary, but in general, it may include a RootSum.
3. Full Risch algorithm:
- The Risch algorithm is a complete decision
procedure for integrating elementary functions, which means that
given any elementary function, it will either compute an
elementary antiderivative, or else prove that none exists.
Currently, part of transcendental case is implemented, meaning
elementary integrals containing exponentials, logarithms, and
(soon!) trigonometric functions can be computed. The algebraic
case, e.g., functions containing roots, is much more difficult
and is not implemented yet.
- If the routine fails (because the integrand is not elementary, or
because a case is not implemented yet), it continues on to the
next algorithms below. If the routine proves that the integrals
is nonelementary, it still moves on to the algorithms below,
because we might be able to find a closed-form solution in terms
of special functions. If risch=True, however, it will stop here.
4. The Meijer G-Function algorithm:
- This algorithm works by first rewriting the integrand in terms of
very general Meijer G-Function (meijerg in SymPy), integrating
it, and then rewriting the result back, if possible. This
algorithm is particularly powerful for definite integrals (which
is actually part of a different method of Integral), since it can
compute closed-form solutions of definite integrals even when no
closed-form indefinite integral exists. But it also is capable
of computing many indefinite integrals as well.
- Another advantage of this method is that it can use some results
about the Meijer G-Function to give a result in terms of a
Piecewise expression, which allows to express conditionally
convergent integrals.
- Setting meijerg=True will cause integrate() to use only this
method.
5. The "manual integration" algorithm:
- This algorithm tries to mimic how a person would find an
antiderivative by hand, for example by looking for a
substitution or applying integration by parts. This algorithm
does not handle as many integrands but can return results in a
more familiar form.
- Sometimes this algorithm can evaluate parts of an integral; in
this case integrate() will try to evaluate the rest of the
integrand using the other methods here.
- Setting manual=True will cause integrate() to use only this
method.
6. The Heuristic Risch algorithm:
- This is a heuristic version of the Risch algorithm, meaning that
it is not deterministic. This is tried as a last resort because
it can be very slow. It is still used because not enough of the
full Risch algorithm is implemented, so that there are still some
integrals that can only be computed using this method. The goal
is to implement enough of the Risch and Meijer G-function methods
so that this can be deleted.
Setting heurisch=True will cause integrate() to use only this
method. Set heurisch=False to not use it.
"""
from sympy.integrals.risch import risch_integrate, NonElementaryIntegral
from sympy.integrals.manualintegrate import manualintegrate
if risch:
try:
return risch_integrate(f, x, conds=conds)
except NotImplementedError:
return None
if manual:
try:
result = manualintegrate(f, x)
if result is not None and result.func != Integral:
return result
except (ValueError, PolynomialError):
pass
eval_kwargs = {"meijerg": meijerg, "risch": risch, "manual": manual,
"heurisch": heurisch, "conds": conds}
# if it is a poly(x) then let the polynomial integrate itself (fast)
#
# It is important to make this check first, otherwise the other code
# will return a SymPy expression instead of a Polynomial.
#
# see Polynomial for details.
if isinstance(f, Poly) and not (manual or meijerg or risch):
# Note: this is deprecated, but the deprecation warning is already
# issued in the Integral constructor.
return f.integrate(x)
# Piecewise antiderivatives need to call special integrate.
if isinstance(f, Piecewise):
return f.piecewise_integrate(x, **eval_kwargs)
# let's cut it short if `f` does not depend on `x`; if
# x is only a dummy, that will be handled below
if not f.has(x):
return f*x
# try to convert to poly(x) and then integrate if successful (fast)
poly = f.as_poly(x)
if poly is not None and not (manual or meijerg or risch):
return poly.integrate().as_expr()
if risch is not False:
try:
result, i = risch_integrate(f, x, separate_integral=True,
conds=conds)
except NotImplementedError:
pass
else:
if i:
# There was a nonelementary integral. Try integrating it.
# if no part of the NonElementaryIntegral is integrated by
# the Risch algorithm, then use the original function to
# integrate, instead of re-written one
if result == 0:
return NonElementaryIntegral(f, x).doit(risch=False)
else:
return result + i.doit(risch=False)
else:
return result
# since Integral(f=g1+g2+...) == Integral(g1) + Integral(g2) + ...
# we are going to handle Add terms separately,
# if `f` is not Add -- we only have one term
# Note that in general, this is a bad idea, because Integral(g1) +
# Integral(g2) might not be computable, even if Integral(g1 + g2) is.
# For example, Integral(x**x + x**x*log(x)). But many heuristics only
# work term-wise. So we compute this step last, after trying
# risch_integrate. We also try risch_integrate again in this loop,
# because maybe the integral is a sum of an elementary part and a
# nonelementary part (like erf(x) + exp(x)). risch_integrate() is
# quite fast, so this is acceptable.
from sympy.simplify.fu import sincos_to_sum
parts = []
args = Add.make_args(f)
for g in args:
coeff, g = g.as_independent(x)
# g(x) = const
if g is S.One and not meijerg:
parts.append(coeff*x)
continue
# g(x) = expr + O(x**n)
order_term = g.getO()
if order_term is not None:
h = self._eval_integral(g.removeO(), x, **eval_kwargs)
if h is not None:
h_order_expr = self._eval_integral(order_term.expr, x, **eval_kwargs)
if h_order_expr is not None:
h_order_term = order_term.func(
h_order_expr, *order_term.variables)
parts.append(coeff*(h + h_order_term))
continue
# NOTE: if there is O(x**n) and we fail to integrate then
# there is no point in trying other methods because they
# will fail, too.
return None
# c
# g(x) = (a*x+b)
if g.is_Pow and not g.exp.has(x) and not meijerg:
a = Wild('a', exclude=[x])
b = Wild('b', exclude=[x])
M = g.base.match(a*x + b)
if M is not None:
if g.exp == -1:
h = log(g.base)
elif conds != 'piecewise':
h = g.base**(g.exp + 1) / (g.exp + 1)
else:
h1 = log(g.base)
h2 = g.base**(g.exp + 1) / (g.exp + 1)
h = Piecewise((h2, Ne(g.exp, -1)), (h1, True))
parts.append(coeff * h / M[a])
continue
# poly(x)
# g(x) = -------
# poly(x)
if g.is_rational_function(x) and not (manual or meijerg or risch):
parts.append(coeff * ratint(g, x))
continue
if not (manual or meijerg or risch):
# g(x) = Mul(trig)
h = trigintegrate(g, x, conds=conds)
if h is not None:
parts.append(coeff * h)
continue
# g(x) has at least a DiracDelta term
h = deltaintegrate(g, x)
if h is not None:
parts.append(coeff * h)
continue
from .singularityfunctions import singularityintegrate
# g(x) has at least a Singularity Function term
h = singularityintegrate(g, x)
if h is not None:
parts.append(coeff * h)
continue
# Try risch again.
if risch is not False:
try:
h, i = risch_integrate(g, x,
separate_integral=True, conds=conds)
except NotImplementedError:
h = None
else:
if i:
h = h + i.doit(risch=False)
parts.append(coeff*h)
continue
# fall back to heurisch
if heurisch is not False:
from sympy.integrals.heurisch import (heurisch as heurisch_,
heurisch_wrapper)
try:
if conds == 'piecewise':
h = heurisch_wrapper(g, x, hints=[])
else:
h = heurisch_(g, x, hints=[])
except PolynomialError:
# XXX: this exception means there is a bug in the
# implementation of heuristic Risch integration
# algorithm.
h = None
else:
h = None
if meijerg is not False and h is None:
# rewrite using G functions
try:
h = meijerint_indefinite(g, x)
except NotImplementedError:
_debug('NotImplementedError from meijerint_definite')
if h is not None:
parts.append(coeff * h)
continue
if h is None and manual is not False:
try:
result = manualintegrate(g, x)
if result is not None and not isinstance(result, Integral):
if result.has(Integral) and not manual:
# Try to have other algorithms do the integrals
# manualintegrate can't handle,
# unless we were asked to use manual only.
# Keep the rest of eval_kwargs in case another
# method was set to False already
new_eval_kwargs = eval_kwargs
new_eval_kwargs["manual"] = False
new_eval_kwargs["final"] = False
result = result.func(*[
arg.doit(**new_eval_kwargs) if
arg.has(Integral) else arg
for arg in result.args
]).expand(multinomial=False,
log=False,
power_exp=False,
power_base=False)
if not result.has(Integral):
parts.append(coeff * result)
continue
except (ValueError, PolynomialError):
# can't handle some SymPy expressions
pass
# if we failed maybe it was because we had
# a product that could have been expanded,
# so let's try an expansion of the whole
# thing before giving up; we don't try this
# at the outset because there are things
# that cannot be solved unless they are
# NOT expanded e.g., x**x*(1+log(x)). There
# should probably be a checker somewhere in this
# routine to look for such cases and try to do
# collection on the expressions if they are already
# in an expanded form
if not h and len(args) == 1:
f = sincos_to_sum(f).expand(mul=True, deep=False)
if f.is_Add:
# Note: risch will be identical on the expanded
# expression, but maybe it will be able to pick out parts,
# like x*(exp(x) + erf(x)).
return self._eval_integral(f, x, **eval_kwargs)
if h is not None:
parts.append(coeff * h)
else:
return None
return Add(*parts)
def _eval_lseries(self, x, logx=None, cdir=0):
expr = self.as_dummy()
symb = x
for l in expr.limits:
if x in l[1:]:
symb = l[0]
break
for term in expr.function.lseries(symb, logx):
yield integrate(term, *expr.limits)
def _eval_nseries(self, x, n, logx=None, cdir=0):
symb = x
for l in self.limits:
if x in l[1:]:
symb = l[0]
break
terms, order = self.function.nseries(
x=symb, n=n, logx=logx).as_coeff_add(Order)
order = [o.subs(symb, x) for o in order]
return integrate(terms, *self.limits) + Add(*order)*x
def _eval_as_leading_term(self, x, logx=None, cdir=0):
series_gen = self.args[0].lseries(x)
for leading_term in series_gen:
if leading_term != 0:
break
return integrate(leading_term, *self.args[1:])
def _eval_simplify(self, **kwargs):
expr = factor_terms(self)
if isinstance(expr, Integral):
from sympy.simplify.simplify import simplify
return expr.func(*[simplify(i, **kwargs) for i in expr.args])
return expr.simplify(**kwargs)
def as_sum(self, n=None, method="midpoint", evaluate=True):
"""
Approximates a definite integral by a sum.
Parameters
==========
n :
The number of subintervals to use, optional.
method :
One of: 'left', 'right', 'midpoint', 'trapezoid'.
evaluate : bool
If False, returns an unevaluated Sum expression. The default
is True, evaluate the sum.
Notes
=====
These methods of approximate integration are described in [1].
Examples
========
>>> from sympy import Integral, sin, sqrt
>>> from sympy.abc import x, n
>>> e = Integral(sin(x), (x, 3, 7))
>>> e
Integral(sin(x), (x, 3, 7))
For demonstration purposes, this interval will only be split into 2
regions, bounded by [3, 5] and [5, 7].
The left-hand rule uses function evaluations at the left of each
interval:
>>> e.as_sum(2, 'left')
2*sin(5) + 2*sin(3)
The midpoint rule uses evaluations at the center of each interval:
>>> e.as_sum(2, 'midpoint')
2*sin(4) + 2*sin(6)
The right-hand rule uses function evaluations at the right of each
interval:
>>> e.as_sum(2, 'right')
2*sin(5) + 2*sin(7)
The trapezoid rule uses function evaluations on both sides of the
intervals. This is equivalent to taking the average of the left and
right hand rule results:
>>> s = e.as_sum(2, 'trapezoid')
>>> s
2*sin(5) + sin(3) + sin(7)
>>> (e.as_sum(2, 'left') + e.as_sum(2, 'right'))/2 == s
True
Here, the discontinuity at x = 0 can be avoided by using the
midpoint or right-hand method:
>>> e = Integral(1/sqrt(x), (x, 0, 1))
>>> e.as_sum(5).n(4)
1.730
>>> e.as_sum(10).n(4)
1.809
>>> e.doit().n(4) # the actual value is 2
2.000
The left- or trapezoid method will encounter the discontinuity and
return infinity:
>>> e.as_sum(5, 'left')
zoo
The number of intervals can be symbolic. If omitted, a dummy symbol
will be used for it.
>>> e = Integral(x**2, (x, 0, 2))
>>> e.as_sum(n, 'right').expand()
8/3 + 4/n + 4/(3*n**2)
This shows that the midpoint rule is more accurate, as its error
term decays as the square of n:
>>> e.as_sum(method='midpoint').expand()
8/3 - 2/(3*_n**2)
A symbolic sum is returned with evaluate=False:
>>> e.as_sum(n, 'midpoint', evaluate=False)
2*Sum((2*_k/n - 1/n)**2, (_k, 1, n))/n
See Also
========
Integral.doit : Perform the integration using any hints
References
==========
.. [1] https://en.wikipedia.org/wiki/Riemann_sum#Riemann_summation_methods
"""
from sympy.concrete.summations import Sum
limits = self.limits
if len(limits) > 1:
raise NotImplementedError(
"Multidimensional midpoint rule not implemented yet")
else:
limit = limits[0]
if (len(limit) != 3 or limit[1].is_finite is False or
limit[2].is_finite is False):
raise ValueError("Expecting a definite integral over "
"a finite interval.")
if n is None:
n = Dummy('n', integer=True, positive=True)
else:
n = sympify(n)
if (n.is_positive is False or n.is_integer is False or
n.is_finite is False):
raise ValueError("n must be a positive integer, got %s" % n)
x, a, b = limit
dx = (b - a)/n
k = Dummy('k', integer=True, positive=True)
f = self.function
if method == "left":
result = dx*Sum(f.subs(x, a + (k-1)*dx), (k, 1, n))
elif method == "right":
result = dx*Sum(f.subs(x, a + k*dx), (k, 1, n))
elif method == "midpoint":
result = dx*Sum(f.subs(x, a + k*dx - dx/2), (k, 1, n))
elif method == "trapezoid":
result = dx*((f.subs(x, a) + f.subs(x, b))/2 +
Sum(f.subs(x, a + k*dx), (k, 1, n - 1)))
else:
raise ValueError("Unknown method %s" % method)
return result.doit() if evaluate else result
def principal_value(self, **kwargs):
"""
Compute the Cauchy Principal Value of the definite integral of a real function in the given interval
on the real axis.
Explanation
===========
In mathematics, the Cauchy principal value, is a method for assigning values to certain improper
integrals which would otherwise be undefined.
Examples
========
>>> from sympy import Integral, oo
>>> from sympy.abc import x
>>> Integral(x+1, (x, -oo, oo)).principal_value()
oo
>>> f = 1 / (x**3)
>>> Integral(f, (x, -oo, oo)).principal_value()
0
>>> Integral(f, (x, -10, 10)).principal_value()
0
>>> Integral(f, (x, -10, oo)).principal_value() + Integral(f, (x, -oo, 10)).principal_value()
0
References
==========
.. [1] https://en.wikipedia.org/wiki/Cauchy_principal_value
.. [2] https://mathworld.wolfram.com/CauchyPrincipalValue.html
"""
if len(self.limits) != 1 or len(list(self.limits[0])) != 3:
raise ValueError("You need to insert a variable, lower_limit, and upper_limit correctly to calculate "
"cauchy's principal value")
x, a, b = self.limits[0]
if not (a.is_comparable and b.is_comparable and a <= b):
raise ValueError("The lower_limit must be smaller than or equal to the upper_limit to calculate "
"cauchy's principal value. Also, a and b need to be comparable.")
if a == b:
return S.Zero
from sympy.calculus.singularities import singularities
r = Dummy('r')
f = self.function
singularities_list = [s for s in singularities(f, x) if s.is_comparable and a <= s <= b]
for i in singularities_list:
if i in (a, b):
raise ValueError(
'The principal value is not defined in the given interval due to singularity at %d.' % (i))
F = integrate(f, x, **kwargs)
if F.has(Integral):
return self
if a is -oo and b is oo:
I = limit(F - F.subs(x, -x), x, oo)
else:
I = limit(F, x, b, '-') - limit(F, x, a, '+')
for s in singularities_list:
I += limit(((F.subs(x, s - r)) - F.subs(x, s + r)), r, 0, '+')
return I
def integrate(*args, meijerg=None, conds='piecewise', risch=None, heurisch=None, manual=None, **kwargs):
"""integrate(f, var, ...)
.. deprecated:: 1.6
Using ``integrate()`` with :class:`~.Poly` is deprecated. Use
:meth:`.Poly.integrate` instead. See :ref:`deprecated-integrate-poly`.
Explanation
===========
Compute definite or indefinite integral of one or more variables
using Risch-Norman algorithm and table lookup. This procedure is
able to handle elementary algebraic and transcendental functions
and also a huge class of special functions, including Airy,
Bessel, Whittaker and Lambert.
var can be:
- a symbol -- indefinite integration
- a tuple (symbol, a) -- indefinite integration with result
given with ``a`` replacing ``symbol``
- a tuple (symbol, a, b) -- definite integration
Several variables can be specified, in which case the result is
multiple integration. (If var is omitted and the integrand is
univariate, the indefinite integral in that variable will be performed.)
Indefinite integrals are returned without terms that are independent
of the integration variables. (see examples)
Definite improper integrals often entail delicate convergence
conditions. Pass conds='piecewise', 'separate' or 'none' to have
these returned, respectively, as a Piecewise function, as a separate
result (i.e. result will be a tuple), or not at all (default is
'piecewise').
**Strategy**
SymPy uses various approaches to definite integration. One method is to
find an antiderivative for the integrand, and then use the fundamental
theorem of calculus. Various functions are implemented to integrate
polynomial, rational and trigonometric functions, and integrands
containing DiracDelta terms.
SymPy also implements the part of the Risch algorithm, which is a decision
procedure for integrating elementary functions, i.e., the algorithm can
either find an elementary antiderivative, or prove that one does not
exist. There is also a (very successful, albeit somewhat slow) general
implementation of the heuristic Risch algorithm. This algorithm will
eventually be phased out as more of the full Risch algorithm is
implemented. See the docstring of Integral._eval_integral() for more
details on computing the antiderivative using algebraic methods.
The option risch=True can be used to use only the (full) Risch algorithm.
This is useful if you want to know if an elementary function has an
elementary antiderivative. If the indefinite Integral returned by this
function is an instance of NonElementaryIntegral, that means that the
Risch algorithm has proven that integral to be non-elementary. Note that
by default, additional methods (such as the Meijer G method outlined
below) are tried on these integrals, as they may be expressible in terms
of special functions, so if you only care about elementary answers, use
risch=True. Also note that an unevaluated Integral returned by this
function is not necessarily a NonElementaryIntegral, even with risch=True,
as it may just be an indication that the particular part of the Risch
algorithm needed to integrate that function is not yet implemented.
Another family of strategies comes from re-writing the integrand in
terms of so-called Meijer G-functions. Indefinite integrals of a
single G-function can always be computed, and the definite integral
of a product of two G-functions can be computed from zero to
infinity. Various strategies are implemented to rewrite integrands
as G-functions, and use this information to compute integrals (see
the ``meijerint`` module).
The option manual=True can be used to use only an algorithm that tries
to mimic integration by hand. This algorithm does not handle as many
integrands as the other algorithms implemented but may return results in
a more familiar form. The ``manualintegrate`` module has functions that
return the steps used (see the module docstring for more information).
In general, the algebraic methods work best for computing
antiderivatives of (possibly complicated) combinations of elementary
functions. The G-function methods work best for computing definite
integrals from zero to infinity of moderately complicated
combinations of special functions, or indefinite integrals of very
simple combinations of special functions.
The strategy employed by the integration code is as follows:
- If computing a definite integral, and both limits are real,
and at least one limit is +- oo, try the G-function method of
definite integration first.
- Try to find an antiderivative, using all available methods, ordered
by performance (that is try fastest method first, slowest last; in
particular polynomial integration is tried first, Meijer
G-functions second to last, and heuristic Risch last).
- If still not successful, try G-functions irrespective of the
limits.
The option meijerg=True, False, None can be used to, respectively:
always use G-function methods and no others, never use G-function
methods, or use all available methods (in order as described above).
It defaults to None.
Examples
========
>>> from sympy import integrate, log, exp, oo
>>> from sympy.abc import a, x, y
>>> integrate(x*y, x)
x**2*y/2
>>> integrate(log(x), x)
x*log(x) - x
>>> integrate(log(x), (x, 1, a))
a*log(a) - a + 1
>>> integrate(x)
x**2/2
Terms that are independent of x are dropped by indefinite integration:
>>> from sympy import sqrt
>>> integrate(sqrt(1 + x), (x, 0, x))
2*(x + 1)**(3/2)/3 - 2/3
>>> integrate(sqrt(1 + x), x)
2*(x + 1)**(3/2)/3
>>> integrate(x*y)
Traceback (most recent call last):
...
ValueError: specify integration variables to integrate x*y
Note that ``integrate(x)`` syntax is meant only for convenience
in interactive sessions and should be avoided in library code.
>>> integrate(x**a*exp(-x), (x, 0, oo)) # same as conds='piecewise'
Piecewise((gamma(a + 1), re(a) > -1),
(Integral(x**a*exp(-x), (x, 0, oo)), True))
>>> integrate(x**a*exp(-x), (x, 0, oo), conds='none')
gamma(a + 1)
>>> integrate(x**a*exp(-x), (x, 0, oo), conds='separate')
(gamma(a + 1), re(a) > -1)
See Also
========
Integral, Integral.doit
"""
doit_flags = {
'deep': False,
'meijerg': meijerg,
'conds': conds,
'risch': risch,
'heurisch': heurisch,
'manual': manual
}
integral = Integral(*args, **kwargs)
if isinstance(integral, Integral):
return integral.doit(**doit_flags)
else:
new_args = [a.doit(**doit_flags) if isinstance(a, Integral) else a
for a in integral.args]
return integral.func(*new_args)
def line_integrate(field, curve, vars):
"""line_integrate(field, Curve, variables)
Compute the line integral.
Examples
========
>>> from sympy import Curve, line_integrate, E, ln
>>> from sympy.abc import x, y, t
>>> C = Curve([E**t + 1, E**t - 1], (t, 0, ln(2)))
>>> line_integrate(x + y, C, [x, y])
3*sqrt(2)
See Also
========
sympy.integrals.integrals.integrate, Integral
"""
from sympy.geometry import Curve
F = sympify(field)
if not F:
raise ValueError(
"Expecting function specifying field as first argument.")
if not isinstance(curve, Curve):
raise ValueError("Expecting Curve entity as second argument.")
if not is_sequence(vars):
raise ValueError("Expecting ordered iterable for variables.")
if len(curve.functions) != len(vars):
raise ValueError("Field variable size does not match curve dimension.")
if curve.parameter in vars:
raise ValueError("Curve parameter clashes with field parameters.")
# Calculate derivatives for line parameter functions
# F(r) -> F(r(t)) and finally F(r(t)*r'(t))
Ft = F
dldt = 0
for i, var in enumerate(vars):
_f = curve.functions[i]
_dn = diff(_f, curve.parameter)
# ...arc length
dldt = dldt + (_dn * _dn)
Ft = Ft.subs(var, _f)
Ft = Ft * sqrt(dldt)
integral = Integral(Ft, curve.limits).doit(deep=False)
return integral
### Property function dispatching ###
@shape.register(Integral)
def _(expr):
return shape(expr.function)
# Delayed imports
from .deltafunctions import deltaintegrate
from .meijerint import meijerint_definite, meijerint_indefinite, _debug
from .trigonometry import trigintegrate
PK ]ZZZ��Q�� � sympy/integrals/intpoly.py"""
Module to implement integration of uni/bivariate polynomials over
2D Polytopes and uni/bi/trivariate polynomials over 3D Polytopes.
Uses evaluation techniques as described in Chin et al. (2015) [1].
References
===========
.. [1] Chin, Eric B., Jean B. Lasserre, and N. Sukumar. "Numerical integration
of homogeneous functions on convex and nonconvex polygons and polyhedra."
Computational Mechanics 56.6 (2015): 967-981
PDF link : http://dilbert.engr.ucdavis.edu/~suku/quadrature/cls-integration.pdf
"""
from functools import cmp_to_key
from sympy.abc import x, y, z
from sympy.core import S, diff, Expr, Symbol
from sympy.core.sympify import _sympify
from sympy.geometry import Segment2D, Polygon, Point, Point2D
from sympy.polys.polytools import LC, gcd_list, degree_list, Poly
from sympy.simplify.simplify import nsimplify
def polytope_integrate(poly, expr=None, *, clockwise=False, max_degree=None):
"""Integrates polynomials over 2/3-Polytopes.
Explanation
===========
This function accepts the polytope in ``poly`` and the function in ``expr``
(uni/bi/trivariate polynomials are implemented) and returns
the exact integral of ``expr`` over ``poly``.
Parameters
==========
poly : The input Polygon.
expr : The input polynomial.
clockwise : Binary value to sort input points of 2-Polytope clockwise.(Optional)
max_degree : The maximum degree of any monomial of the input polynomial.(Optional)
Examples
========
>>> from sympy.abc import x, y
>>> from sympy import Point, Polygon
>>> from sympy.integrals.intpoly import polytope_integrate
>>> polygon = Polygon(Point(0, 0), Point(0, 1), Point(1, 1), Point(1, 0))
>>> polys = [1, x, y, x*y, x**2*y, x*y**2]
>>> expr = x*y
>>> polytope_integrate(polygon, expr)
1/4
>>> polytope_integrate(polygon, polys, max_degree=3)
{1: 1, x: 1/2, y: 1/2, x*y: 1/4, x*y**2: 1/6, x**2*y: 1/6}
"""
if clockwise:
if isinstance(poly, Polygon):
poly = Polygon(*point_sort(poly.vertices), evaluate=False)
else:
raise TypeError("clockwise=True works for only 2-Polytope"
"V-representation input")
if isinstance(poly, Polygon):
# For Vertex Representation(2D case)
hp_params = hyperplane_parameters(poly)
facets = poly.sides
elif len(poly[0]) == 2:
# For Hyperplane Representation(2D case)
plen = len(poly)
if len(poly[0][0]) == 2:
intersections = [intersection(poly[(i - 1) % plen], poly[i],
"plane2D")
for i in range(0, plen)]
hp_params = poly
lints = len(intersections)
facets = [Segment2D(intersections[i],
intersections[(i + 1) % lints])
for i in range(lints)]
else:
raise NotImplementedError("Integration for H-representation 3D"
"case not implemented yet.")
else:
# For Vertex Representation(3D case)
vertices = poly[0]
facets = poly[1:]
hp_params = hyperplane_parameters(facets, vertices)
if max_degree is None:
if expr is None:
raise TypeError('Input expression must be a valid SymPy expression')
return main_integrate3d(expr, facets, vertices, hp_params)
if max_degree is not None:
result = {}
if expr is not None:
f_expr = []
for e in expr:
_ = decompose(e)
if len(_) == 1 and not _.popitem()[0]:
f_expr.append(e)
elif Poly(e).total_degree() <= max_degree:
f_expr.append(e)
expr = f_expr
if not isinstance(expr, list) and expr is not None:
raise TypeError('Input polynomials must be list of expressions')
if len(hp_params[0][0]) == 3:
result_dict = main_integrate3d(0, facets, vertices, hp_params,
max_degree)
else:
result_dict = main_integrate(0, facets, hp_params, max_degree)
if expr is None:
return result_dict
for poly in expr:
poly = _sympify(poly)
if poly not in result:
if poly.is_zero:
result[S.Zero] = S.Zero
continue
integral_value = S.Zero
monoms = decompose(poly, separate=True)
for monom in monoms:
monom = nsimplify(monom)
coeff, m = strip(monom)
integral_value += result_dict[m] * coeff
result[poly] = integral_value
return result
if expr is None:
raise TypeError('Input expression must be a valid SymPy expression')
return main_integrate(expr, facets, hp_params)
def strip(monom):
if monom.is_zero:
return S.Zero, S.Zero
elif monom.is_number:
return monom, S.One
else:
coeff = LC(monom)
return coeff, monom / coeff
def _polynomial_integrate(polynomials, facets, hp_params):
dims = (x, y)
dim_length = len(dims)
integral_value = S.Zero
for deg in polynomials:
poly_contribute = S.Zero
facet_count = 0
for hp in hp_params:
value_over_boundary = integration_reduction(facets,
facet_count,
hp[0], hp[1],
polynomials[deg],
dims, deg)
poly_contribute += value_over_boundary * (hp[1] / norm(hp[0]))
facet_count += 1
poly_contribute /= (dim_length + deg)
integral_value += poly_contribute
return integral_value
def main_integrate3d(expr, facets, vertices, hp_params, max_degree=None):
"""Function to translate the problem of integrating uni/bi/tri-variate
polynomials over a 3-Polytope to integrating over its faces.
This is done using Generalized Stokes' Theorem and Euler's Theorem.
Parameters
==========
expr :
The input polynomial.
facets :
Faces of the 3-Polytope(expressed as indices of `vertices`).
vertices :
Vertices that constitute the Polytope.
hp_params :
Hyperplane Parameters of the facets.
max_degree : optional
Max degree of constituent monomial in given list of polynomial.
Examples
========
>>> from sympy.integrals.intpoly import main_integrate3d, \
hyperplane_parameters
>>> cube = [[(0, 0, 0), (0, 0, 5), (0, 5, 0), (0, 5, 5), (5, 0, 0),\
(5, 0, 5), (5, 5, 0), (5, 5, 5)],\
[2, 6, 7, 3], [3, 7, 5, 1], [7, 6, 4, 5], [1, 5, 4, 0],\
[3, 1, 0, 2], [0, 4, 6, 2]]
>>> vertices = cube[0]
>>> faces = cube[1:]
>>> hp_params = hyperplane_parameters(faces, vertices)
>>> main_integrate3d(1, faces, vertices, hp_params)
-125
"""
result = {}
dims = (x, y, z)
dim_length = len(dims)
if max_degree:
grad_terms = gradient_terms(max_degree, 3)
flat_list = [term for z_terms in grad_terms
for x_term in z_terms
for term in x_term]
for term in flat_list:
result[term[0]] = 0
for facet_count, hp in enumerate(hp_params):
a, b = hp[0], hp[1]
x0 = vertices[facets[facet_count][0]]
for i, monom in enumerate(flat_list):
# Every monomial is a tuple :
# (term, x_degree, y_degree, z_degree, value over boundary)
expr, x_d, y_d, z_d, z_index, y_index, x_index, _ = monom
degree = x_d + y_d + z_d
if b.is_zero:
value_over_face = S.Zero
else:
value_over_face = \
integration_reduction_dynamic(facets, facet_count, a,
b, expr, degree, dims,
x_index, y_index,
z_index, x0, grad_terms,
i, vertices, hp)
monom[7] = value_over_face
result[expr] += value_over_face * \
(b / norm(a)) / (dim_length + x_d + y_d + z_d)
return result
else:
integral_value = S.Zero
polynomials = decompose(expr)
for deg in polynomials:
poly_contribute = S.Zero
facet_count = 0
for i, facet in enumerate(facets):
hp = hp_params[i]
if hp[1].is_zero:
continue
pi = polygon_integrate(facet, hp, i, facets, vertices, expr, deg)
poly_contribute += pi *\
(hp[1] / norm(tuple(hp[0])))
facet_count += 1
poly_contribute /= (dim_length + deg)
integral_value += poly_contribute
return integral_value
def main_integrate(expr, facets, hp_params, max_degree=None):
"""Function to translate the problem of integrating univariate/bivariate
polynomials over a 2-Polytope to integrating over its boundary facets.
This is done using Generalized Stokes's Theorem and Euler's Theorem.
Parameters
==========
expr :
The input polynomial.
facets :
Facets(Line Segments) of the 2-Polytope.
hp_params :
Hyperplane Parameters of the facets.
max_degree : optional
The maximum degree of any monomial of the input polynomial.
>>> from sympy.abc import x, y
>>> from sympy.integrals.intpoly import main_integrate,\
hyperplane_parameters
>>> from sympy import Point, Polygon
>>> triangle = Polygon(Point(0, 3), Point(5, 3), Point(1, 1))
>>> facets = triangle.sides
>>> hp_params = hyperplane_parameters(triangle)
>>> main_integrate(x**2 + y**2, facets, hp_params)
325/6
"""
dims = (x, y)
dim_length = len(dims)
result = {}
if max_degree:
grad_terms = [[0, 0, 0, 0]] + gradient_terms(max_degree)
for facet_count, hp in enumerate(hp_params):
a, b = hp[0], hp[1]
x0 = facets[facet_count].points[0]
for i, monom in enumerate(grad_terms):
# Every monomial is a tuple :
# (term, x_degree, y_degree, value over boundary)
m, x_d, y_d, _ = monom
value = result.get(m, None)
degree = S.Zero
if b.is_zero:
value_over_boundary = S.Zero
else:
degree = x_d + y_d
value_over_boundary = \
integration_reduction_dynamic(facets, facet_count, a,
b, m, degree, dims, x_d,
y_d, max_degree, x0,
grad_terms, i)
monom[3] = value_over_boundary
if value is not None:
result[m] += value_over_boundary * \
(b / norm(a)) / (dim_length + degree)
else:
result[m] = value_over_boundary * \
(b / norm(a)) / (dim_length + degree)
return result
else:
if not isinstance(expr, list):
polynomials = decompose(expr)
return _polynomial_integrate(polynomials, facets, hp_params)
else:
return {e: _polynomial_integrate(decompose(e), facets, hp_params) for e in expr}
def polygon_integrate(facet, hp_param, index, facets, vertices, expr, degree):
"""Helper function to integrate the input uni/bi/trivariate polynomial
over a certain face of the 3-Polytope.
Parameters
==========
facet :
Particular face of the 3-Polytope over which ``expr`` is integrated.
index :
The index of ``facet`` in ``facets``.
facets :
Faces of the 3-Polytope(expressed as indices of `vertices`).
vertices :
Vertices that constitute the facet.
expr :
The input polynomial.
degree :
Degree of ``expr``.
Examples
========
>>> from sympy.integrals.intpoly import polygon_integrate
>>> cube = [[(0, 0, 0), (0, 0, 5), (0, 5, 0), (0, 5, 5), (5, 0, 0),\
(5, 0, 5), (5, 5, 0), (5, 5, 5)],\
[2, 6, 7, 3], [3, 7, 5, 1], [7, 6, 4, 5], [1, 5, 4, 0],\
[3, 1, 0, 2], [0, 4, 6, 2]]
>>> facet = cube[1]
>>> facets = cube[1:]
>>> vertices = cube[0]
>>> polygon_integrate(facet, [(0, 1, 0), 5], 0, facets, vertices, 1, 0)
-25
"""
expr = S(expr)
if expr.is_zero:
return S.Zero
result = S.Zero
x0 = vertices[facet[0]]
facet_len = len(facet)
for i, fac in enumerate(facet):
side = (vertices[fac], vertices[facet[(i + 1) % facet_len]])
result += distance_to_side(x0, side, hp_param[0]) *\
lineseg_integrate(facet, i, side, expr, degree)
if not expr.is_number:
expr = diff(expr, x) * x0[0] + diff(expr, y) * x0[1] +\
diff(expr, z) * x0[2]
result += polygon_integrate(facet, hp_param, index, facets, vertices,
expr, degree - 1)
result /= (degree + 2)
return result
def distance_to_side(point, line_seg, A):
"""Helper function to compute the signed distance between given 3D point
and a line segment.
Parameters
==========
point : 3D Point
line_seg : Line Segment
Examples
========
>>> from sympy.integrals.intpoly import distance_to_side
>>> point = (0, 0, 0)
>>> distance_to_side(point, [(0, 0, 1), (0, 1, 0)], (1, 0, 0))
-sqrt(2)/2
"""
x1, x2 = line_seg
rev_normal = [-1 * S(i)/norm(A) for i in A]
vector = [x2[i] - x1[i] for i in range(0, 3)]
vector = [vector[i]/norm(vector) for i in range(0, 3)]
n_side = cross_product((0, 0, 0), rev_normal, vector)
vectorx0 = [line_seg[0][i] - point[i] for i in range(0, 3)]
dot_product = sum(vectorx0[i] * n_side[i] for i in range(0, 3))
return dot_product
def lineseg_integrate(polygon, index, line_seg, expr, degree):
"""Helper function to compute the line integral of ``expr`` over ``line_seg``.
Parameters
===========
polygon :
Face of a 3-Polytope.
index :
Index of line_seg in polygon.
line_seg :
Line Segment.
Examples
========
>>> from sympy.integrals.intpoly import lineseg_integrate
>>> polygon = [(0, 5, 0), (5, 5, 0), (5, 5, 5), (0, 5, 5)]
>>> line_seg = [(0, 5, 0), (5, 5, 0)]
>>> lineseg_integrate(polygon, 0, line_seg, 1, 0)
5
"""
expr = _sympify(expr)
if expr.is_zero:
return S.Zero
result = S.Zero
x0 = line_seg[0]
distance = norm(tuple([line_seg[1][i] - line_seg[0][i] for i in
range(3)]))
if isinstance(expr, Expr):
expr_dict = {x: line_seg[1][0],
y: line_seg[1][1],
z: line_seg[1][2]}
result += distance * expr.subs(expr_dict)
else:
result += distance * expr
expr = diff(expr, x) * x0[0] + diff(expr, y) * x0[1] +\
diff(expr, z) * x0[2]
result += lineseg_integrate(polygon, index, line_seg, expr, degree - 1)
result /= (degree + 1)
return result
def integration_reduction(facets, index, a, b, expr, dims, degree):
"""Helper method for main_integrate. Returns the value of the input
expression evaluated over the polytope facet referenced by a given index.
Parameters
===========
facets :
List of facets of the polytope.
index :
Index referencing the facet to integrate the expression over.
a :
Hyperplane parameter denoting direction.
b :
Hyperplane parameter denoting distance.
expr :
The expression to integrate over the facet.
dims :
List of symbols denoting axes.
degree :
Degree of the homogeneous polynomial.
Examples
========
>>> from sympy.abc import x, y
>>> from sympy.integrals.intpoly import integration_reduction,\
hyperplane_parameters
>>> from sympy import Point, Polygon
>>> triangle = Polygon(Point(0, 3), Point(5, 3), Point(1, 1))
>>> facets = triangle.sides
>>> a, b = hyperplane_parameters(triangle)[0]
>>> integration_reduction(facets, 0, a, b, 1, (x, y), 0)
5
"""
expr = _sympify(expr)
if expr.is_zero:
return expr
value = S.Zero
x0 = facets[index].points[0]
m = len(facets)
gens = (x, y)
inner_product = diff(expr, gens[0]) * x0[0] + diff(expr, gens[1]) * x0[1]
if inner_product != 0:
value += integration_reduction(facets, index, a, b,
inner_product, dims, degree - 1)
value += left_integral2D(m, index, facets, x0, expr, gens)
return value/(len(dims) + degree - 1)
def left_integral2D(m, index, facets, x0, expr, gens):
"""Computes the left integral of Eq 10 in Chin et al.
For the 2D case, the integral is just an evaluation of the polynomial
at the intersection of two facets which is multiplied by the distance
between the first point of facet and that intersection.
Parameters
==========
m :
No. of hyperplanes.
index :
Index of facet to find intersections with.
facets :
List of facets(Line Segments in 2D case).
x0 :
First point on facet referenced by index.
expr :
Input polynomial
gens :
Generators which generate the polynomial
Examples
========
>>> from sympy.abc import x, y
>>> from sympy.integrals.intpoly import left_integral2D
>>> from sympy import Point, Polygon
>>> triangle = Polygon(Point(0, 3), Point(5, 3), Point(1, 1))
>>> facets = triangle.sides
>>> left_integral2D(3, 0, facets, facets[0].points[0], 1, (x, y))
5
"""
value = S.Zero
for j in range(m):
intersect = ()
if j in ((index - 1) % m, (index + 1) % m):
intersect = intersection(facets[index], facets[j], "segment2D")
if intersect:
distance_origin = norm(tuple(map(lambda x, y: x - y,
intersect, x0)))
if is_vertex(intersect):
if isinstance(expr, Expr):
if len(gens) == 3:
expr_dict = {gens[0]: intersect[0],
gens[1]: intersect[1],
gens[2]: intersect[2]}
else:
expr_dict = {gens[0]: intersect[0],
gens[1]: intersect[1]}
value += distance_origin * expr.subs(expr_dict)
else:
value += distance_origin * expr
return value
def integration_reduction_dynamic(facets, index, a, b, expr, degree, dims,
x_index, y_index, max_index, x0,
monomial_values, monom_index, vertices=None,
hp_param=None):
"""The same integration_reduction function which uses a dynamic
programming approach to compute terms by using the values of the integral
of previously computed terms.
Parameters
==========
facets :
Facets of the Polytope.
index :
Index of facet to find intersections with.(Used in left_integral()).
a, b :
Hyperplane parameters.
expr :
Input monomial.
degree :
Total degree of ``expr``.
dims :
Tuple denoting axes variables.
x_index :
Exponent of 'x' in ``expr``.
y_index :
Exponent of 'y' in ``expr``.
max_index :
Maximum exponent of any monomial in ``monomial_values``.
x0 :
First point on ``facets[index]``.
monomial_values :
List of monomial values constituting the polynomial.
monom_index :
Index of monomial whose integration is being found.
vertices : optional
Coordinates of vertices constituting the 3-Polytope.
hp_param : optional
Hyperplane Parameter of the face of the facets[index].
Examples
========
>>> from sympy.abc import x, y
>>> from sympy.integrals.intpoly import (integration_reduction_dynamic, \
hyperplane_parameters)
>>> from sympy import Point, Polygon
>>> triangle = Polygon(Point(0, 3), Point(5, 3), Point(1, 1))
>>> facets = triangle.sides
>>> a, b = hyperplane_parameters(triangle)[0]
>>> x0 = facets[0].points[0]
>>> monomial_values = [[0, 0, 0, 0], [1, 0, 0, 5],\
[y, 0, 1, 15], [x, 1, 0, None]]
>>> integration_reduction_dynamic(facets, 0, a, b, x, 1, (x, y), 1, 0, 1,\
x0, monomial_values, 3)
25/2
"""
value = S.Zero
m = len(facets)
if expr == S.Zero:
return expr
if len(dims) == 2:
if not expr.is_number:
_, x_degree, y_degree, _ = monomial_values[monom_index]
x_index = monom_index - max_index + \
x_index - 2 if x_degree > 0 else 0
y_index = monom_index - 1 if y_degree > 0 else 0
x_value, y_value =\
monomial_values[x_index][3], monomial_values[y_index][3]
value += x_degree * x_value * x0[0] + y_degree * y_value * x0[1]
value += left_integral2D(m, index, facets, x0, expr, dims)
else:
# For 3D use case the max_index contains the z_degree of the term
z_index = max_index
if not expr.is_number:
x_degree, y_degree, z_degree = y_index,\
z_index - x_index - y_index, x_index
x_value = monomial_values[z_index - 1][y_index - 1][x_index][7]\
if x_degree > 0 else 0
y_value = monomial_values[z_index - 1][y_index][x_index][7]\
if y_degree > 0 else 0
z_value = monomial_values[z_index - 1][y_index][x_index - 1][7]\
if z_degree > 0 else 0
value += x_degree * x_value * x0[0] + y_degree * y_value * x0[1] \
+ z_degree * z_value * x0[2]
value += left_integral3D(facets, index, expr,
vertices, hp_param, degree)
return value / (len(dims) + degree - 1)
def left_integral3D(facets, index, expr, vertices, hp_param, degree):
"""Computes the left integral of Eq 10 in Chin et al.
Explanation
===========
For the 3D case, this is the sum of the integral values over constituting
line segments of the face (which is accessed by facets[index]) multiplied
by the distance between the first point of facet and that line segment.
Parameters
==========
facets :
List of faces of the 3-Polytope.
index :
Index of face over which integral is to be calculated.
expr :
Input polynomial.
vertices :
List of vertices that constitute the 3-Polytope.
hp_param :
The hyperplane parameters of the face.
degree :
Degree of the ``expr``.
Examples
========
>>> from sympy.integrals.intpoly import left_integral3D
>>> cube = [[(0, 0, 0), (0, 0, 5), (0, 5, 0), (0, 5, 5), (5, 0, 0),\
(5, 0, 5), (5, 5, 0), (5, 5, 5)],\
[2, 6, 7, 3], [3, 7, 5, 1], [7, 6, 4, 5], [1, 5, 4, 0],\
[3, 1, 0, 2], [0, 4, 6, 2]]
>>> facets = cube[1:]
>>> vertices = cube[0]
>>> left_integral3D(facets, 3, 1, vertices, ([0, -1, 0], -5), 0)
-50
"""
value = S.Zero
facet = facets[index]
x0 = vertices[facet[0]]
facet_len = len(facet)
for i, fac in enumerate(facet):
side = (vertices[fac], vertices[facet[(i + 1) % facet_len]])
value += distance_to_side(x0, side, hp_param[0]) * \
lineseg_integrate(facet, i, side, expr, degree)
return value
def gradient_terms(binomial_power=0, no_of_gens=2):
"""Returns a list of all the possible monomials between
0 and y**binomial_power for 2D case and z**binomial_power
for 3D case.
Parameters
==========
binomial_power :
Power upto which terms are generated.
no_of_gens :
Denotes whether terms are being generated for 2D or 3D case.
Examples
========
>>> from sympy.integrals.intpoly import gradient_terms
>>> gradient_terms(2)
[[1, 0, 0, 0], [y, 0, 1, 0], [y**2, 0, 2, 0], [x, 1, 0, 0],
[x*y, 1, 1, 0], [x**2, 2, 0, 0]]
>>> gradient_terms(2, 3)
[[[[1, 0, 0, 0, 0, 0, 0, 0]]], [[[y, 0, 1, 0, 1, 0, 0, 0],
[z, 0, 0, 1, 1, 0, 1, 0]], [[x, 1, 0, 0, 1, 1, 0, 0]]],
[[[y**2, 0, 2, 0, 2, 0, 0, 0], [y*z, 0, 1, 1, 2, 0, 1, 0],
[z**2, 0, 0, 2, 2, 0, 2, 0]], [[x*y, 1, 1, 0, 2, 1, 0, 0],
[x*z, 1, 0, 1, 2, 1, 1, 0]], [[x**2, 2, 0, 0, 2, 2, 0, 0]]]]
"""
if no_of_gens == 2:
count = 0
terms = [None] * int((binomial_power ** 2 + 3 * binomial_power + 2) / 2)
for x_count in range(0, binomial_power + 1):
for y_count in range(0, binomial_power - x_count + 1):
terms[count] = [x**x_count*y**y_count,
x_count, y_count, 0]
count += 1
else:
terms = [[[[x ** x_count * y ** y_count *
z ** (z_count - y_count - x_count),
x_count, y_count, z_count - y_count - x_count,
z_count, x_count, z_count - y_count - x_count, 0]
for y_count in range(z_count - x_count, -1, -1)]
for x_count in range(0, z_count + 1)]
for z_count in range(0, binomial_power + 1)]
return terms
def hyperplane_parameters(poly, vertices=None):
"""A helper function to return the hyperplane parameters
of which the facets of the polytope are a part of.
Parameters
==========
poly :
The input 2/3-Polytope.
vertices :
Vertex indices of 3-Polytope.
Examples
========
>>> from sympy import Point, Polygon
>>> from sympy.integrals.intpoly import hyperplane_parameters
>>> hyperplane_parameters(Polygon(Point(0, 3), Point(5, 3), Point(1, 1)))
[((0, 1), 3), ((1, -2), -1), ((-2, -1), -3)]
>>> cube = [[(0, 0, 0), (0, 0, 5), (0, 5, 0), (0, 5, 5), (5, 0, 0),\
(5, 0, 5), (5, 5, 0), (5, 5, 5)],\
[2, 6, 7, 3], [3, 7, 5, 1], [7, 6, 4, 5], [1, 5, 4, 0],\
[3, 1, 0, 2], [0, 4, 6, 2]]
>>> hyperplane_parameters(cube[1:], cube[0])
[([0, -1, 0], -5), ([0, 0, -1], -5), ([-1, 0, 0], -5),
([0, 1, 0], 0), ([1, 0, 0], 0), ([0, 0, 1], 0)]
"""
if isinstance(poly, Polygon):
vertices = list(poly.vertices) + [poly.vertices[0]] # Close the polygon
params = [None] * (len(vertices) - 1)
for i in range(len(vertices) - 1):
v1 = vertices[i]
v2 = vertices[i + 1]
a1 = v1[1] - v2[1]
a2 = v2[0] - v1[0]
b = v2[0] * v1[1] - v2[1] * v1[0]
factor = gcd_list([a1, a2, b])
b = S(b) / factor
a = (S(a1) / factor, S(a2) / factor)
params[i] = (a, b)
else:
params = [None] * len(poly)
for i, polygon in enumerate(poly):
v1, v2, v3 = [vertices[vertex] for vertex in polygon[:3]]
normal = cross_product(v1, v2, v3)
b = sum(normal[j] * v1[j] for j in range(0, 3))
fac = gcd_list(normal)
if fac.is_zero:
fac = 1
normal = [j / fac for j in normal]
b = b / fac
params[i] = (normal, b)
return params
def cross_product(v1, v2, v3):
"""Returns the cross-product of vectors (v2 - v1) and (v3 - v1)
That is : (v2 - v1) X (v3 - v1)
"""
v2 = [v2[j] - v1[j] for j in range(0, 3)]
v3 = [v3[j] - v1[j] for j in range(0, 3)]
return [v3[2] * v2[1] - v3[1] * v2[2],
v3[0] * v2[2] - v3[2] * v2[0],
v3[1] * v2[0] - v3[0] * v2[1]]
def best_origin(a, b, lineseg, expr):
"""Helper method for polytope_integrate. Currently not used in the main
algorithm.
Explanation
===========
Returns a point on the lineseg whose vector inner product with the
divergence of `expr` yields an expression with the least maximum
total power.
Parameters
==========
a :
Hyperplane parameter denoting direction.
b :
Hyperplane parameter denoting distance.
lineseg :
Line segment on which to find the origin.
expr :
The expression which determines the best point.
Algorithm(currently works only for 2D use case)
===============================================
1 > Firstly, check for edge cases. Here that would refer to vertical
or horizontal lines.
2 > If input expression is a polynomial containing more than one generator
then find out the total power of each of the generators.
x**2 + 3 + x*y + x**4*y**5 ---> {x: 7, y: 6}
If expression is a constant value then pick the first boundary point
of the line segment.
3 > First check if a point exists on the line segment where the value of
the highest power generator becomes 0. If not check if the value of
the next highest becomes 0. If none becomes 0 within line segment
constraints then pick the first boundary point of the line segment.
Actually, any point lying on the segment can be picked as best origin
in the last case.
Examples
========
>>> from sympy.integrals.intpoly import best_origin
>>> from sympy.abc import x, y
>>> from sympy import Point, Segment2D
>>> l = Segment2D(Point(0, 3), Point(1, 1))
>>> expr = x**3*y**7
>>> best_origin((2, 1), 3, l, expr)
(0, 3.0)
"""
a1, b1 = lineseg.points[0]
def x_axis_cut(ls):
"""Returns the point where the input line segment
intersects the x-axis.
Parameters
==========
ls :
Line segment
"""
p, q = ls.points
if p.y.is_zero:
return tuple(p)
elif q.y.is_zero:
return tuple(q)
elif p.y/q.y < S.Zero:
return p.y * (p.x - q.x)/(q.y - p.y) + p.x, S.Zero
else:
return ()
def y_axis_cut(ls):
"""Returns the point where the input line segment
intersects the y-axis.
Parameters
==========
ls :
Line segment
"""
p, q = ls.points
if p.x.is_zero:
return tuple(p)
elif q.x.is_zero:
return tuple(q)
elif p.x/q.x < S.Zero:
return S.Zero, p.x * (p.y - q.y)/(q.x - p.x) + p.y
else:
return ()
gens = (x, y)
power_gens = {}
for i in gens:
power_gens[i] = S.Zero
if len(gens) > 1:
# Special case for vertical and horizontal lines
if len(gens) == 2:
if a[0] == 0:
if y_axis_cut(lineseg):
return S.Zero, b/a[1]
else:
return a1, b1
elif a[1] == 0:
if x_axis_cut(lineseg):
return b/a[0], S.Zero
else:
return a1, b1
if isinstance(expr, Expr): # Find the sum total of power of each
if expr.is_Add: # generator and store in a dictionary.
for monomial in expr.args:
if monomial.is_Pow:
if monomial.args[0] in gens:
power_gens[monomial.args[0]] += monomial.args[1]
else:
for univariate in monomial.args:
term_type = len(univariate.args)
if term_type == 0 and univariate in gens:
power_gens[univariate] += 1
elif term_type == 2 and univariate.args[0] in gens:
power_gens[univariate.args[0]] +=\
univariate.args[1]
elif expr.is_Mul:
for term in expr.args:
term_type = len(term.args)
if term_type == 0 and term in gens:
power_gens[term] += 1
elif term_type == 2 and term.args[0] in gens:
power_gens[term.args[0]] += term.args[1]
elif expr.is_Pow:
power_gens[expr.args[0]] = expr.args[1]
elif expr.is_Symbol:
power_gens[expr] += 1
else: # If `expr` is a constant take first vertex of the line segment.
return a1, b1
# TODO : This part is quite hacky. Should be made more robust with
# TODO : respect to symbol names and scalable w.r.t higher dimensions.
power_gens = sorted(power_gens.items(), key=lambda k: str(k[0]))
if power_gens[0][1] >= power_gens[1][1]:
if y_axis_cut(lineseg):
x0 = (S.Zero, b / a[1])
elif x_axis_cut(lineseg):
x0 = (b / a[0], S.Zero)
else:
x0 = (a1, b1)
else:
if x_axis_cut(lineseg):
x0 = (b/a[0], S.Zero)
elif y_axis_cut(lineseg):
x0 = (S.Zero, b/a[1])
else:
x0 = (a1, b1)
else:
x0 = (b/a[0])
return x0
def decompose(expr, separate=False):
"""Decomposes an input polynomial into homogeneous ones of
smaller or equal degree.
Explanation
===========
Returns a dictionary with keys as the degree of the smaller
constituting polynomials. Values are the constituting polynomials.
Parameters
==========
expr : Expr
Polynomial(SymPy expression).
separate : bool
If True then simply return a list of the constituent monomials
If not then break up the polynomial into constituent homogeneous
polynomials.
Examples
========
>>> from sympy.abc import x, y
>>> from sympy.integrals.intpoly import decompose
>>> decompose(x**2 + x*y + x + y + x**3*y**2 + y**5)
{1: x + y, 2: x**2 + x*y, 5: x**3*y**2 + y**5}
>>> decompose(x**2 + x*y + x + y + x**3*y**2 + y**5, True)
{x, x**2, y, y**5, x*y, x**3*y**2}
"""
poly_dict = {}
if isinstance(expr, Expr) and not expr.is_number:
if expr.is_Symbol:
poly_dict[1] = expr
elif expr.is_Add:
symbols = expr.atoms(Symbol)
degrees = [(sum(degree_list(monom, *symbols)), monom)
for monom in expr.args]
if separate:
return {monom[1] for monom in degrees}
else:
for monom in degrees:
degree, term = monom
if poly_dict.get(degree):
poly_dict[degree] += term
else:
poly_dict[degree] = term
elif expr.is_Pow:
_, degree = expr.args
poly_dict[degree] = expr
else: # Now expr can only be of `Mul` type
degree = 0
for term in expr.args:
term_type = len(term.args)
if term_type == 0 and term.is_Symbol:
degree += 1
elif term_type == 2:
degree += term.args[1]
poly_dict[degree] = expr
else:
poly_dict[0] = expr
if separate:
return set(poly_dict.values())
return poly_dict
def point_sort(poly, normal=None, clockwise=True):
"""Returns the same polygon with points sorted in clockwise or
anti-clockwise order.
Note that it's necessary for input points to be sorted in some order
(clockwise or anti-clockwise) for the integration algorithm to work.
As a convention algorithm has been implemented keeping clockwise
orientation in mind.
Parameters
==========
poly:
2D or 3D Polygon.
normal : optional
The normal of the plane which the 3-Polytope is a part of.
clockwise : bool, optional
Returns points sorted in clockwise order if True and
anti-clockwise if False.
Examples
========
>>> from sympy.integrals.intpoly import point_sort
>>> from sympy import Point
>>> point_sort([Point(0, 0), Point(1, 0), Point(1, 1)])
[Point2D(1, 1), Point2D(1, 0), Point2D(0, 0)]
"""
pts = poly.vertices if isinstance(poly, Polygon) else poly
n = len(pts)
if n < 2:
return list(pts)
order = S.One if clockwise else S.NegativeOne
dim = len(pts[0])
if dim == 2:
center = Point(sum((vertex.x for vertex in pts)) / n,
sum((vertex.y for vertex in pts)) / n)
else:
center = Point(sum((vertex.x for vertex in pts)) / n,
sum((vertex.y for vertex in pts)) / n,
sum((vertex.z for vertex in pts)) / n)
def compare(a, b):
if a.x - center.x >= S.Zero and b.x - center.x < S.Zero:
return -order
elif a.x - center.x < 0 and b.x - center.x >= 0:
return order
elif a.x - center.x == 0 and b.x - center.x == 0:
if a.y - center.y >= 0 or b.y - center.y >= 0:
return -order if a.y > b.y else order
return -order if b.y > a.y else order
det = (a.x - center.x) * (b.y - center.y) -\
(b.x - center.x) * (a.y - center.y)
if det < 0:
return -order
elif det > 0:
return order
first = (a.x - center.x) * (a.x - center.x) +\
(a.y - center.y) * (a.y - center.y)
second = (b.x - center.x) * (b.x - center.x) +\
(b.y - center.y) * (b.y - center.y)
return -order if first > second else order
def compare3d(a, b):
det = cross_product(center, a, b)
dot_product = sum(det[i] * normal[i] for i in range(0, 3))
if dot_product < 0:
return -order
elif dot_product > 0:
return order
return sorted(pts, key=cmp_to_key(compare if dim==2 else compare3d))
def norm(point):
"""Returns the Euclidean norm of a point from origin.
Parameters
==========
point:
This denotes a point in the dimension_al spac_e.
Examples
========
>>> from sympy.integrals.intpoly import norm
>>> from sympy import Point
>>> norm(Point(2, 7))
sqrt(53)
"""
half = S.Half
if isinstance(point, (list, tuple)):
return sum(coord ** 2 for coord in point) ** half
elif isinstance(point, Point):
if isinstance(point, Point2D):
return (point.x ** 2 + point.y ** 2) ** half
else:
return (point.x ** 2 + point.y ** 2 + point.z) ** half
elif isinstance(point, dict):
return sum(i**2 for i in point.values()) ** half
def intersection(geom_1, geom_2, intersection_type):
"""Returns intersection between geometric objects.
Explanation
===========
Note that this function is meant for use in integration_reduction and
at that point in the calling function the lines denoted by the segments
surely intersect within segment boundaries. Coincident lines are taken
to be non-intersecting. Also, the hyperplane intersection for 2D case is
also implemented.
Parameters
==========
geom_1, geom_2:
The input line segments.
Examples
========
>>> from sympy.integrals.intpoly import intersection
>>> from sympy import Point, Segment2D
>>> l1 = Segment2D(Point(1, 1), Point(3, 5))
>>> l2 = Segment2D(Point(2, 0), Point(2, 5))
>>> intersection(l1, l2, "segment2D")
(2, 3)
>>> p1 = ((-1, 0), 0)
>>> p2 = ((0, 1), 1)
>>> intersection(p1, p2, "plane2D")
(0, 1)
"""
if intersection_type[:-2] == "segment":
if intersection_type == "segment2D":
x1, y1 = geom_1.points[0]
x2, y2 = geom_1.points[1]
x3, y3 = geom_2.points[0]
x4, y4 = geom_2.points[1]
elif intersection_type == "segment3D":
x1, y1, z1 = geom_1.points[0]
x2, y2, z2 = geom_1.points[1]
x3, y3, z3 = geom_2.points[0]
x4, y4, z4 = geom_2.points[1]
denom = (x1 - x2) * (y3 - y4) - (y1 - y2) * (x3 - x4)
if denom:
t1 = x1 * y2 - y1 * x2
t2 = x3 * y4 - x4 * y3
return (S(t1 * (x3 - x4) - t2 * (x1 - x2)) / denom,
S(t1 * (y3 - y4) - t2 * (y1 - y2)) / denom)
if intersection_type[:-2] == "plane":
if intersection_type == "plane2D": # Intersection of hyperplanes
a1x, a1y = geom_1[0]
a2x, a2y = geom_2[0]
b1, b2 = geom_1[1], geom_2[1]
denom = a1x * a2y - a2x * a1y
if denom:
return (S(b1 * a2y - b2 * a1y) / denom,
S(b2 * a1x - b1 * a2x) / denom)
def is_vertex(ent):
"""If the input entity is a vertex return True.
Parameter
=========
ent :
Denotes a geometric entity representing a point.
Examples
========
>>> from sympy import Point
>>> from sympy.integrals.intpoly import is_vertex
>>> is_vertex((2, 3))
True
>>> is_vertex((2, 3, 6))
True
>>> is_vertex(Point(2, 3))
True
"""
if isinstance(ent, tuple):
if len(ent) in [2, 3]:
return True
elif isinstance(ent, Point):
return True
return False
def plot_polytope(poly):
"""Plots the 2D polytope using the functions written in plotting
module which in turn uses matplotlib backend.
Parameter
=========
poly:
Denotes a 2-Polytope.
"""
from sympy.plotting.plot import Plot, List2DSeries
xl = [vertex.x for vertex in poly.vertices]
yl = [vertex.y for vertex in poly.vertices]
xl.append(poly.vertices[0].x) # Closing the polygon
yl.append(poly.vertices[0].y)
l2ds = List2DSeries(xl, yl)
p = Plot(l2ds, axes='label_axes=True')
p.show()
def plot_polynomial(expr):
"""Plots the polynomial using the functions written in
plotting module which in turn uses matplotlib backend.
Parameter
=========
expr:
Denotes a polynomial(SymPy expression).
"""
from sympy.plotting.plot import plot3d, plot
gens = expr.free_symbols
if len(gens) == 2:
plot3d(expr)
else:
plot(expr)
PK ]ZZZ�'"�R �R sympy/integrals/laplace.py"""Laplace Transforms"""
import sys
import sympy
from sympy.core import S, pi, I
from sympy.core.add import Add
from sympy.core.cache import cacheit
from sympy.core.expr import Expr
from sympy.core.function import (
AppliedUndef, Derivative, expand, expand_complex, expand_mul, expand_trig,
Lambda, WildFunction, diff, Subs)
from sympy.core.mul import Mul, prod
from sympy.core.relational import (
_canonical, Ge, Gt, Lt, Unequality, Eq, Ne, Relational)
from sympy.core.sorting import ordered
from sympy.core.symbol import Dummy, symbols, Wild
from sympy.functions.elementary.complexes import (
re, im, arg, Abs, polar_lift, periodic_argument)
from sympy.functions.elementary.exponential import exp, log
from sympy.functions.elementary.hyperbolic import cosh, coth, sinh, asinh
from sympy.functions.elementary.miscellaneous import Max, Min, sqrt
from sympy.functions.elementary.piecewise import (
Piecewise, piecewise_exclusive)
from sympy.functions.elementary.trigonometric import cos, sin, atan, sinc
from sympy.functions.special.bessel import besseli, besselj, besselk, bessely
from sympy.functions.special.delta_functions import DiracDelta, Heaviside
from sympy.functions.special.error_functions import erf, erfc, Ei
from sympy.functions.special.gamma_functions import (
digamma, gamma, lowergamma, uppergamma)
from sympy.functions.special.singularity_functions import SingularityFunction
from sympy.integrals import integrate, Integral
from sympy.integrals.transforms import (
_simplify, IntegralTransform, IntegralTransformError)
from sympy.logic.boolalg import to_cnf, conjuncts, disjuncts, Or, And
from sympy.matrices.matrixbase import MatrixBase
from sympy.polys.matrices.linsolve import _lin_eq2dict
from sympy.polys.polyerrors import PolynomialError
from sympy.polys.polyroots import roots
from sympy.polys.polytools import Poly
from sympy.polys.rationaltools import together
from sympy.polys.rootoftools import RootSum
from sympy.utilities.exceptions import (
sympy_deprecation_warning, SymPyDeprecationWarning, ignore_warnings)
from sympy.utilities.misc import debugf
_LT_level = 0
def DEBUG_WRAP(func):
def wrap(*args, **kwargs):
from sympy import SYMPY_DEBUG
global _LT_level
if not SYMPY_DEBUG:
return func(*args, **kwargs)
if _LT_level == 0:
print('\n' + '-'*78, file=sys.stderr)
print('-LT- %s%s%s' % (' '*_LT_level, func.__name__, args),
file=sys.stderr)
_LT_level += 1
if (
func.__name__ == '_laplace_transform_integration' or
func.__name__ == '_inverse_laplace_transform_integration'):
sympy.SYMPY_DEBUG = False
print('**** %sIntegrating ...' % (' '*_LT_level), file=sys.stderr)
result = func(*args, **kwargs)
sympy.SYMPY_DEBUG = True
else:
result = func(*args, **kwargs)
_LT_level -= 1
print('-LT- %s---> %s' % (' '*_LT_level, result), file=sys.stderr)
if _LT_level == 0:
print('-'*78 + '\n', file=sys.stderr)
return result
return wrap
def _debug(text):
from sympy import SYMPY_DEBUG
global _LT_level
if SYMPY_DEBUG:
print('-LT- %s%s' % (' '*_LT_level, text), file=sys.stderr)
def _simplifyconds(expr, s, a):
r"""
Naively simplify some conditions occurring in ``expr``,
given that `\operatorname{Re}(s) > a`.
Examples
========
>>> from sympy.integrals.laplace import _simplifyconds
>>> from sympy.abc import x
>>> from sympy import sympify as S
>>> _simplifyconds(abs(x**2) < 1, x, 1)
False
>>> _simplifyconds(abs(x**2) < 1, x, 2)
False
>>> _simplifyconds(abs(x**2) < 1, x, 0)
Abs(x**2) < 1
>>> _simplifyconds(abs(1/x**2) < 1, x, 1)
True
>>> _simplifyconds(S(1) < abs(x), x, 1)
True
>>> _simplifyconds(S(1) < abs(1/x), x, 1)
False
>>> from sympy import Ne
>>> _simplifyconds(Ne(1, x**3), x, 1)
True
>>> _simplifyconds(Ne(1, x**3), x, 2)
True
>>> _simplifyconds(Ne(1, x**3), x, 0)
Ne(1, x**3)
"""
def power(ex):
if ex == s:
return 1
if ex.is_Pow and ex.base == s:
return ex.exp
return None
def bigger(ex1, ex2):
""" Return True only if |ex1| > |ex2|, False only if |ex1| < |ex2|.
Else return None. """
if ex1.has(s) and ex2.has(s):
return None
if isinstance(ex1, Abs):
ex1 = ex1.args[0]
if isinstance(ex2, Abs):
ex2 = ex2.args[0]
if ex1.has(s):
return bigger(1/ex2, 1/ex1)
n = power(ex2)
if n is None:
return None
try:
if n > 0 and (Abs(ex1) <= Abs(a)**n) == S.true:
return False
if n < 0 and (Abs(ex1) >= Abs(a)**n) == S.true:
return True
except TypeError:
return None
def replie(x, y):
""" simplify x < y """
if (not (x.is_positive or isinstance(x, Abs))
or not (y.is_positive or isinstance(y, Abs))):
return (x < y)
r = bigger(x, y)
if r is not None:
return not r
return (x < y)
def replue(x, y):
b = bigger(x, y)
if b in (True, False):
return True
return Unequality(x, y)
def repl(ex, *args):
if ex in (True, False):
return bool(ex)
return ex.replace(*args)
from sympy.simplify.radsimp import collect_abs
expr = collect_abs(expr)
expr = repl(expr, Lt, replie)
expr = repl(expr, Gt, lambda x, y: replie(y, x))
expr = repl(expr, Unequality, replue)
return S(expr)
@DEBUG_WRAP
def expand_dirac_delta(expr):
"""
Expand an expression involving DiractDelta to get it as a linear
combination of DiracDelta functions.
"""
return _lin_eq2dict(expr, expr.atoms(DiracDelta))
@DEBUG_WRAP
def _laplace_transform_integration(f, t, s_, *, simplify):
""" The backend function for doing Laplace transforms by integration.
This backend assumes that the frontend has already split sums
such that `f` is to an addition anymore.
"""
s = Dummy('s')
if f.has(DiracDelta):
return None
F = integrate(f*exp(-s*t), (t, S.Zero, S.Infinity))
if not F.has(Integral):
return _simplify(F.subs(s, s_), simplify), S.NegativeInfinity, S.true
if not F.is_Piecewise:
return None
F, cond = F.args[0]
if F.has(Integral):
return None
def process_conds(conds):
""" Turn ``conds`` into a strip and auxiliary conditions. """
from sympy.solvers.inequalities import _solve_inequality
a = S.NegativeInfinity
aux = S.true
conds = conjuncts(to_cnf(conds))
p, q, w1, w2, w3, w4, w5 = symbols(
'p q w1 w2 w3 w4 w5', cls=Wild, exclude=[s])
patterns = (
p*Abs(arg((s + w3)*q)) < w2,
p*Abs(arg((s + w3)*q)) <= w2,
Abs(periodic_argument((s + w3)**p*q, w1)) < w2,
Abs(periodic_argument((s + w3)**p*q, w1)) <= w2,
Abs(periodic_argument((polar_lift(s + w3))**p*q, w1)) < w2,
Abs(periodic_argument((polar_lift(s + w3))**p*q, w1)) <= w2)
for c in conds:
a_ = S.Infinity
aux_ = []
for d in disjuncts(c):
if d.is_Relational and s in d.rhs.free_symbols:
d = d.reversed
if d.is_Relational and isinstance(d, (Ge, Gt)):
d = d.reversedsign
for pat in patterns:
m = d.match(pat)
if m:
break
if m and m[q].is_positive and m[w2]/m[p] == pi/2:
d = -re(s + m[w3]) < 0
m = d.match(p - cos(w1*Abs(arg(s*w5))*w2)*Abs(s**w3)**w4 < 0)
if not m:
m = d.match(
cos(p - Abs(periodic_argument(s**w1*w5, q))*w2) *
Abs(s**w3)**w4 < 0)
if not m:
m = d.match(
p - cos(
Abs(periodic_argument(polar_lift(s)**w1*w5, q))*w2
)*Abs(s**w3)**w4 < 0)
if m and all(m[wild].is_positive for wild in [
w1, w2, w3, w4, w5]):
d = re(s) > m[p]
d_ = d.replace(
re, lambda x: x.expand().as_real_imag()[0]).subs(re(s), t)
if (
not d.is_Relational or d.rel_op in ('==', '!=')
or d_.has(s) or not d_.has(t)):
aux_ += [d]
continue
soln = _solve_inequality(d_, t)
if not soln.is_Relational or soln.rel_op in ('==', '!='):
aux_ += [d]
continue
if soln.lts == t:
return None
else:
a_ = Min(soln.lts, a_)
if a_ is not S.Infinity:
a = Max(a_, a)
else:
aux = And(aux, Or(*aux_))
return a, aux.canonical if aux.is_Relational else aux
conds = [process_conds(c) for c in disjuncts(cond)]
conds2 = [x for x in conds if x[1] !=
S.false and x[0] is not S.NegativeInfinity]
if not conds2:
conds2 = [x for x in conds if x[1] != S.false]
conds = list(ordered(conds2))
def cnt(expr):
if expr in (True, False):
return 0
return expr.count_ops()
conds.sort(key=lambda x: (-x[0], cnt(x[1])))
if not conds:
return None
a, aux = conds[0] # XXX is [0] always the right one?
def sbs(expr):
return expr.subs(s, s_)
if simplify:
F = _simplifyconds(F, s, a)
aux = _simplifyconds(aux, s, a)
return _simplify(F.subs(s, s_), simplify), sbs(a), _canonical(sbs(aux))
@DEBUG_WRAP
def _laplace_deep_collect(f, t):
"""
This is an internal helper function that traverses through the epression
tree of `f(t)` and collects arguments. The purpose of it is that
anything like `f(w*t-1*t-c)` will be written as `f((w-1)*t-c)` such that
it can match `f(a*t+b)`.
"""
if not isinstance(f, Expr):
return f
if (p := f.as_poly(t)) is not None:
return p.as_expr()
func = f.func
args = [_laplace_deep_collect(arg, t) for arg in f.args]
return func(*args)
@cacheit
def _laplace_build_rules():
"""
This is an internal helper function that returns the table of Laplace
transform rules in terms of the time variable `t` and the frequency
variable `s`. It is used by ``_laplace_apply_rules``. Each entry is a
tuple containing:
(time domain pattern,
frequency-domain replacement,
condition for the rule to be applied,
convergence plane,
preparation function)
The preparation function is a function with one argument that is applied
to the expression before matching. For most rules it should be
``_laplace_deep_collect``.
"""
t = Dummy('t')
s = Dummy('s')
a = Wild('a', exclude=[t])
b = Wild('b', exclude=[t])
n = Wild('n', exclude=[t])
tau = Wild('tau', exclude=[t])
omega = Wild('omega', exclude=[t])
def dco(f): return _laplace_deep_collect(f, t)
_debug('_laplace_build_rules is building rules')
laplace_transform_rules = [
(a, a/s,
S.true, S.Zero, dco), # 4.2.1
(DiracDelta(a*t-b), exp(-s*b/a)/Abs(a),
Or(And(a > 0, b >= 0), And(a < 0, b <= 0)),
S.NegativeInfinity, dco), # Not in Bateman54
(DiracDelta(a*t-b), S(0),
Or(And(a < 0, b >= 0), And(a > 0, b <= 0)),
S.NegativeInfinity, dco), # Not in Bateman54
(Heaviside(a*t-b), exp(-s*b/a)/s,
And(a > 0, b > 0), S.Zero, dco), # 4.4.1
(Heaviside(a*t-b), (1-exp(-s*b/a))/s,
And(a < 0, b < 0), S.Zero, dco), # 4.4.1
(Heaviside(a*t-b), 1/s,
And(a > 0, b <= 0), S.Zero, dco), # 4.4.1
(Heaviside(a*t-b), 0,
And(a < 0, b > 0), S.Zero, dco), # 4.4.1
(t, 1/s**2,
S.true, S.Zero, dco), # 4.2.3
(1/(a*t+b), -exp(-b/a*s)*Ei(-b/a*s)/a,
Abs(arg(b/a)) < pi, S.Zero, dco), # 4.2.6
(1/sqrt(a*t+b), sqrt(a*pi/s)*exp(b/a*s)*erfc(sqrt(b/a*s))/a,
Abs(arg(b/a)) < pi, S.Zero, dco), # 4.2.18
((a*t+b)**(-S(3)/2),
2*b**(-S(1)/2)-2*(pi*s/a)**(S(1)/2)*exp(b/a*s) * erfc(sqrt(b/a*s))/a,
Abs(arg(b/a)) < pi, S.Zero, dco), # 4.2.20
(sqrt(t)/(t+b), sqrt(pi/s)-pi*sqrt(b)*exp(b*s)*erfc(sqrt(b*s)),
Abs(arg(b)) < pi, S.Zero, dco), # 4.2.22
(1/(a*sqrt(t) + t**(3/2)), pi*a**(S(1)/2)*exp(a*s)*erfc(sqrt(a*s)),
S.true, S.Zero, dco), # Not in Bateman54
(t**n, gamma(n+1)/s**(n+1),
n > -1, S.Zero, dco), # 4.3.1
((a*t+b)**n, uppergamma(n+1, b/a*s)*exp(-b/a*s)/s**(n+1)/a,
And(n > -1, Abs(arg(b/a)) < pi), S.Zero, dco), # 4.3.4
(t**n/(t+a), a**n*gamma(n+1)*uppergamma(-n, a*s),
And(n > -1, Abs(arg(a)) < pi), S.Zero, dco), # 4.3.7
(exp(a*t-tau), exp(-tau)/(s-a),
S.true, re(a), dco), # 4.5.1
(t*exp(a*t-tau), exp(-tau)/(s-a)**2,
S.true, re(a), dco), # 4.5.2
(t**n*exp(a*t), gamma(n+1)/(s-a)**(n+1),
re(n) > -1, re(a), dco), # 4.5.3
(exp(-a*t**2), sqrt(pi/4/a)*exp(s**2/4/a)*erfc(s/sqrt(4*a)),
re(a) > 0, S.Zero, dco), # 4.5.21
(t*exp(-a*t**2),
1/(2*a)-2/sqrt(pi)/(4*a)**(S(3)/2)*s*erfc(s/sqrt(4*a)),
re(a) > 0, S.Zero, dco), # 4.5.22
(exp(-a/t), 2*sqrt(a/s)*besselk(1, 2*sqrt(a*s)),
re(a) >= 0, S.Zero, dco), # 4.5.25
(sqrt(t)*exp(-a/t),
S(1)/2*sqrt(pi/s**3)*(1+2*sqrt(a*s))*exp(-2*sqrt(a*s)),
re(a) >= 0, S.Zero, dco), # 4.5.26
(exp(-a/t)/sqrt(t), sqrt(pi/s)*exp(-2*sqrt(a*s)),
re(a) >= 0, S.Zero, dco), # 4.5.27
(exp(-a/t)/(t*sqrt(t)), sqrt(pi/a)*exp(-2*sqrt(a*s)),
re(a) > 0, S.Zero, dco), # 4.5.28
(t**n*exp(-a/t), 2*(a/s)**((n+1)/2)*besselk(n+1, 2*sqrt(a*s)),
re(a) > 0, S.Zero, dco), # 4.5.29
(exp(-2*sqrt(a*t)),
s**(-1)-sqrt(pi*a)*s**(-S(3)/2)*exp(a/s) * erfc(sqrt(a/s)),
Abs(arg(a)) < pi, S.Zero, dco), # 4.5.31
(exp(-2*sqrt(a*t))/sqrt(t), (pi/s)**(S(1)/2)*exp(a/s)*erfc(sqrt(a/s)),
Abs(arg(a)) < pi, S.Zero, dco), # 4.5.33
(exp(-a*exp(-t)), a**(-s)*lowergamma(s, a),
S.true, S.Zero, dco), # 4.5.36
(exp(-a*exp(t)), a**s*uppergamma(-s, a),
re(a) > 0, S.Zero, dco), # 4.5.37
(log(a*t), -log(exp(S.EulerGamma)*s/a)/s,
a > 0, S.Zero, dco), # 4.6.1
(log(1+a*t), -exp(s/a)/s*Ei(-s/a),
Abs(arg(a)) < pi, S.Zero, dco), # 4.6.4
(log(a*t+b), (log(b)-exp(s/b/a)/s*a*Ei(-s/b))/s*a,
And(a > 0, Abs(arg(b)) < pi), S.Zero, dco), # 4.6.5
(log(t)/sqrt(t), -sqrt(pi/s)*log(4*s*exp(S.EulerGamma)),
S.true, S.Zero, dco), # 4.6.9
(t**n*log(t), gamma(n+1)*s**(-n-1)*(digamma(n+1)-log(s)),
re(n) > -1, S.Zero, dco), # 4.6.11
(log(a*t)**2, (log(exp(S.EulerGamma)*s/a)**2+pi**2/6)/s,
a > 0, S.Zero, dco), # 4.6.13
(sin(omega*t), omega/(s**2+omega**2),
S.true, Abs(im(omega)), dco), # 4,7,1
(Abs(sin(omega*t)), omega/(s**2+omega**2)*coth(pi*s/2/omega),
omega > 0, S.Zero, dco), # 4.7.2
(sin(omega*t)/t, atan(omega/s),
S.true, Abs(im(omega)), dco), # 4.7.16
(sin(omega*t)**2/t, log(1+4*omega**2/s**2)/4,
S.true, 2*Abs(im(omega)), dco), # 4.7.17
(sin(omega*t)**2/t**2,
omega*atan(2*omega/s)-s*log(1+4*omega**2/s**2)/4,
S.true, 2*Abs(im(omega)), dco), # 4.7.20
(sin(2*sqrt(a*t)), sqrt(pi*a)/s/sqrt(s)*exp(-a/s),
S.true, S.Zero, dco), # 4.7.32
(sin(2*sqrt(a*t))/t, pi*erf(sqrt(a/s)),
S.true, S.Zero, dco), # 4.7.34
(cos(omega*t), s/(s**2+omega**2),
S.true, Abs(im(omega)), dco), # 4.7.43
(cos(omega*t)**2, (s**2+2*omega**2)/(s**2+4*omega**2)/s,
S.true, 2*Abs(im(omega)), dco), # 4.7.45
(sqrt(t)*cos(2*sqrt(a*t)), sqrt(pi)/2*s**(-S(5)/2)*(s-2*a)*exp(-a/s),
S.true, S.Zero, dco), # 4.7.66
(cos(2*sqrt(a*t))/sqrt(t), sqrt(pi/s)*exp(-a/s),
S.true, S.Zero, dco), # 4.7.67
(sin(a*t)*sin(b*t), 2*a*b*s/(s**2+(a+b)**2)/(s**2+(a-b)**2),
S.true, Abs(im(a))+Abs(im(b)), dco), # 4.7.78
(cos(a*t)*sin(b*t), b*(s**2-a**2+b**2)/(s**2+(a+b)**2)/(s**2+(a-b)**2),
S.true, Abs(im(a))+Abs(im(b)), dco), # 4.7.79
(cos(a*t)*cos(b*t), s*(s**2+a**2+b**2)/(s**2+(a+b)**2)/(s**2+(a-b)**2),
S.true, Abs(im(a))+Abs(im(b)), dco), # 4.7.80
(sinh(a*t), a/(s**2-a**2),
S.true, Abs(re(a)), dco), # 4.9.1
(cosh(a*t), s/(s**2-a**2),
S.true, Abs(re(a)), dco), # 4.9.2
(sinh(a*t)**2, 2*a**2/(s**3-4*a**2*s),
S.true, 2*Abs(re(a)), dco), # 4.9.3
(cosh(a*t)**2, (s**2-2*a**2)/(s**3-4*a**2*s),
S.true, 2*Abs(re(a)), dco), # 4.9.4
(sinh(a*t)/t, log((s+a)/(s-a))/2,
S.true, Abs(re(a)), dco), # 4.9.12
(t**n*sinh(a*t), gamma(n+1)/2*((s-a)**(-n-1)-(s+a)**(-n-1)),
n > -2, Abs(a), dco), # 4.9.18
(t**n*cosh(a*t), gamma(n+1)/2*((s-a)**(-n-1)+(s+a)**(-n-1)),
n > -1, Abs(a), dco), # 4.9.19
(sinh(2*sqrt(a*t)), sqrt(pi*a)/s/sqrt(s)*exp(a/s),
S.true, S.Zero, dco), # 4.9.34
(cosh(2*sqrt(a*t)), 1/s+sqrt(pi*a)/s/sqrt(s)*exp(a/s)*erf(sqrt(a/s)),
S.true, S.Zero, dco), # 4.9.35
(
sqrt(t)*sinh(2*sqrt(a*t)),
pi**(S(1)/2)*s**(-S(5)/2)*(s/2+a) *
exp(a/s)*erf(sqrt(a/s))-a**(S(1)/2)*s**(-2),
S.true, S.Zero, dco), # 4.9.36
(sqrt(t)*cosh(2*sqrt(a*t)), pi**(S(1)/2)*s**(-S(5)/2)*(s/2+a)*exp(a/s),
S.true, S.Zero, dco), # 4.9.37
(sinh(2*sqrt(a*t))/sqrt(t),
pi**(S(1)/2)*s**(-S(1)/2)*exp(a/s) * erf(sqrt(a/s)),
S.true, S.Zero, dco), # 4.9.38
(cosh(2*sqrt(a*t))/sqrt(t), pi**(S(1)/2)*s**(-S(1)/2)*exp(a/s),
S.true, S.Zero, dco), # 4.9.39
(sinh(sqrt(a*t))**2/sqrt(t), pi**(S(1)/2)/2*s**(-S(1)/2)*(exp(a/s)-1),
S.true, S.Zero, dco), # 4.9.40
(cosh(sqrt(a*t))**2/sqrt(t), pi**(S(1)/2)/2*s**(-S(1)/2)*(exp(a/s)+1),
S.true, S.Zero, dco), # 4.9.41
(erf(a*t), exp(s**2/(2*a)**2)*erfc(s/(2*a))/s,
4*Abs(arg(a)) < pi, S.Zero, dco), # 4.12.2
(erf(sqrt(a*t)), sqrt(a)/sqrt(s+a)/s,
S.true, Max(S.Zero, -re(a)), dco), # 4.12.4
(exp(a*t)*erf(sqrt(a*t)), sqrt(a)/sqrt(s)/(s-a),
S.true, Max(S.Zero, re(a)), dco), # 4.12.5
(erf(sqrt(a/t)/2), (1-exp(-sqrt(a*s)))/s,
re(a) > 0, S.Zero, dco), # 4.12.6
(erfc(sqrt(a*t)), (sqrt(s+a)-sqrt(a))/sqrt(s+a)/s,
S.true, -re(a), dco), # 4.12.9
(exp(a*t)*erfc(sqrt(a*t)), 1/(s+sqrt(a*s)),
S.true, S.Zero, dco), # 4.12.10
(erfc(sqrt(a/t)/2), exp(-sqrt(a*s))/s,
re(a) > 0, S.Zero, dco), # 4.2.11
(besselj(n, a*t), a**n/(sqrt(s**2+a**2)*(s+sqrt(s**2+a**2))**n),
re(n) > -1, Abs(im(a)), dco), # 4.14.1
(t**b*besselj(n, a*t),
2**n/sqrt(pi)*gamma(n+S.Half)*a**n*(s**2+a**2)**(-n-S.Half),
And(re(n) > -S.Half, Eq(b, n)), Abs(im(a)), dco), # 4.14.7
(t**b*besselj(n, a*t),
2**(n+1)/sqrt(pi)*gamma(n+S(3)/2)*a**n*s*(s**2+a**2)**(-n-S(3)/2),
And(re(n) > -1, Eq(b, n+1)), Abs(im(a)), dco), # 4.14.8
(besselj(0, 2*sqrt(a*t)), exp(-a/s)/s,
S.true, S.Zero, dco), # 4.14.25
(t**(b)*besselj(n, 2*sqrt(a*t)), a**(n/2)*s**(-n-1)*exp(-a/s),
And(re(n) > -1, Eq(b, n*S.Half)), S.Zero, dco), # 4.14.30
(besselj(0, a*sqrt(t**2+b*t)),
exp(b*s-b*sqrt(s**2+a**2))/sqrt(s**2+a**2),
Abs(arg(b)) < pi, Abs(im(a)), dco), # 4.15.19
(besseli(n, a*t), a**n/(sqrt(s**2-a**2)*(s+sqrt(s**2-a**2))**n),
re(n) > -1, Abs(re(a)), dco), # 4.16.1
(t**b*besseli(n, a*t),
2**n/sqrt(pi)*gamma(n+S.Half)*a**n*(s**2-a**2)**(-n-S.Half),
And(re(n) > -S.Half, Eq(b, n)), Abs(re(a)), dco), # 4.16.6
(t**b*besseli(n, a*t),
2**(n+1)/sqrt(pi)*gamma(n+S(3)/2)*a**n*s*(s**2-a**2)**(-n-S(3)/2),
And(re(n) > -1, Eq(b, n+1)), Abs(re(a)), dco), # 4.16.7
(t**(b)*besseli(n, 2*sqrt(a*t)), a**(n/2)*s**(-n-1)*exp(a/s),
And(re(n) > -1, Eq(b, n*S.Half)), S.Zero, dco), # 4.16.18
(bessely(0, a*t), -2/pi*asinh(s/a)/sqrt(s**2+a**2),
S.true, Abs(im(a)), dco), # 4.15.44
(besselk(0, a*t), log((s + sqrt(s**2-a**2))/a)/(sqrt(s**2-a**2)),
S.true, -re(a), dco) # 4.16.23
]
return laplace_transform_rules, t, s
@DEBUG_WRAP
def _laplace_rule_timescale(f, t, s):
"""
This function applies the time-scaling rule of the Laplace transform in
a straight-forward way. For example, if it gets ``(f(a*t), t, s)``, it will
compute ``LaplaceTransform(f(t)/a, t, s/a)`` if ``a>0``.
"""
a = Wild('a', exclude=[t])
g = WildFunction('g', nargs=1)
ma1 = f.match(g)
if ma1:
arg = ma1[g].args[0].collect(t)
ma2 = arg.match(a*t)
if ma2 and ma2[a].is_positive and ma2[a] != 1:
_debug(' rule: time scaling (4.1.4)')
r, pr, cr = _laplace_transform(
1/ma2[a]*ma1[g].func(t), t, s/ma2[a], simplify=False)
return (r, pr, cr)
return None
@DEBUG_WRAP
def _laplace_rule_heaviside(f, t, s):
"""
This function deals with time-shifted Heaviside step functions. If the time
shift is positive, it applies the time-shift rule of the Laplace transform.
For example, if it gets ``(Heaviside(t-a)*f(t), t, s)``, it will compute
``exp(-a*s)*LaplaceTransform(f(t+a), t, s)``.
If the time shift is negative, the Heaviside function is simply removed
as it means nothing to the Laplace transform.
The function does not remove a factor ``Heaviside(t)``; this is done by
the simple rules.
"""
a = Wild('a', exclude=[t])
y = Wild('y')
g = Wild('g')
if ma1 := f.match(Heaviside(y) * g):
if ma2 := ma1[y].match(t - a):
if ma2[a].is_positive:
_debug(' rule: time shift (4.1.4)')
r, pr, cr = _laplace_transform(
ma1[g].subs(t, t + ma2[a]), t, s, simplify=False)
return (exp(-ma2[a] * s) * r, pr, cr)
if ma2[a].is_negative:
_debug(
' rule: Heaviside factor; negative time shift (4.1.4)')
r, pr, cr = _laplace_transform(ma1[g], t, s, simplify=False)
return (r, pr, cr)
if ma2 := ma1[y].match(a - t):
if ma2[a].is_positive:
_debug(' rule: Heaviside window open')
r, pr, cr = _laplace_transform(
(1 - Heaviside(t - ma2[a])) * ma1[g], t, s, simplify=False)
return (r, pr, cr)
if ma2[a].is_negative:
_debug(' rule: Heaviside window closed')
return (0, 0, S.true)
return None
@DEBUG_WRAP
def _laplace_rule_exp(f, t, s):
"""
If this function finds a factor ``exp(a*t)``, it applies the
frequency-shift rule of the Laplace transform and adjusts the convergence
plane accordingly. For example, if it gets ``(exp(-a*t)*f(t), t, s)``, it
will compute ``LaplaceTransform(f(t), t, s+a)``.
"""
a = Wild('a', exclude=[t])
y = Wild('y')
z = Wild('z')
ma1 = f.match(exp(y)*z)
if ma1:
ma2 = ma1[y].collect(t).match(a*t)
if ma2:
_debug(' rule: multiply with exp (4.1.5)')
r, pr, cr = _laplace_transform(ma1[z], t, s-ma2[a],
simplify=False)
return (r, pr+re(ma2[a]), cr)
return None
@DEBUG_WRAP
def _laplace_rule_delta(f, t, s):
"""
If this function finds a factor ``DiracDelta(b*t-a)``, it applies the
masking property of the delta distribution. For example, if it gets
``(DiracDelta(t-a)*f(t), t, s)``, it will return
``(f(a)*exp(-a*s), -a, True)``.
"""
# This rule is not in Bateman54
a = Wild('a', exclude=[t])
b = Wild('b', exclude=[t])
y = Wild('y')
z = Wild('z')
ma1 = f.match(DiracDelta(y)*z)
if ma1 and not ma1[z].has(DiracDelta):
ma2 = ma1[y].collect(t).match(b*t-a)
if ma2:
_debug(' rule: multiply with DiracDelta')
loc = ma2[a]/ma2[b]
if re(loc) >= 0 and im(loc) == 0:
fn = exp(-ma2[a]/ma2[b]*s)*ma1[z]
if fn.has(sin, cos):
# Then it may be possible that a sinc() is present in the
# term; let's try this:
fn = fn.rewrite(sinc).ratsimp()
n, d = [x.subs(t, ma2[a]/ma2[b]) for x in fn.as_numer_denom()]
if d != 0:
return (n/d/ma2[b], S.NegativeInfinity, S.true)
else:
return None
else:
return (0, S.NegativeInfinity, S.true)
if ma1[y].is_polynomial(t):
ro = roots(ma1[y], t)
if ro != {} and set(ro.values()) == {1}:
slope = diff(ma1[y], t)
r = Add(
*[exp(-x*s)*ma1[z].subs(t, s)/slope.subs(t, x)
for x in list(ro.keys()) if im(x) == 0 and re(x) >= 0])
return (r, S.NegativeInfinity, S.true)
return None
@DEBUG_WRAP
def _laplace_trig_split(fn):
"""
Helper function for `_laplace_rule_trig`. This function returns two terms
`f` and `g`. `f` contains all product terms with sin, cos, sinh, cosh in
them; `g` contains everything else.
"""
trigs = [S.One]
other = [S.One]
for term in Mul.make_args(fn):
if term.has(sin, cos, sinh, cosh, exp):
trigs.append(term)
else:
other.append(term)
f = Mul(*trigs)
g = Mul(*other)
return f, g
@DEBUG_WRAP
def _laplace_trig_expsum(f, t):
"""
Helper function for `_laplace_rule_trig`. This function expects the `f`
from `_laplace_trig_split`. It returns two lists `xm` and `xn`. `xm` is
a list of dictionaries with keys `k` and `a` representing a function
`k*exp(a*t)`. `xn` is a list of all terms that cannot be brought into
that form, which may happen, e.g., when a trigonometric function has
another function in its argument.
"""
c1 = Wild('c1', exclude=[t])
c0 = Wild('c0', exclude=[t])
p = Wild('p', exclude=[t])
xm = []
xn = []
x1 = f.rewrite(exp).expand()
for term in Add.make_args(x1):
if not term.has(t):
xm.append({'k': term, 'a': 0, re: 0, im: 0})
continue
term = _laplace_deep_collect(term.powsimp(combine='exp'), t)
if (r := term.match(p*exp(c1*t+c0))) is not None:
xm.append({
'k': r[p]*exp(r[c0]), 'a': r[c1],
re: re(r[c1]), im: im(r[c1])})
else:
xn.append(term)
return xm, xn
@DEBUG_WRAP
def _laplace_trig_ltex(xm, t, s):
"""
Helper function for `_laplace_rule_trig`. This function takes the list of
exponentials `xm` from `_laplace_trig_expsum` and simplifies complex
conjugate and real symmetric poles. It returns the result as a sum and
the convergence plane.
"""
results = []
planes = []
def _simpc(coeffs):
nc = coeffs.copy()
for k in range(len(nc)):
ri = nc[k].as_real_imag()
if ri[0].has(im):
nc[k] = nc[k].rewrite(cos)
else:
nc[k] = (ri[0] + I*ri[1]).rewrite(cos)
return nc
def _quadpole(t1, k1, k2, k3, s):
a, k0, a_r, a_i = t1['a'], t1['k'], t1[re], t1[im]
nc = [
k0 + k1 + k2 + k3,
a*(k0 + k1 - k2 - k3) - 2*I*a_i*k1 + 2*I*a_i*k2,
(
a**2*(-k0 - k1 - k2 - k3) +
a*(4*I*a_i*k0 + 4*I*a_i*k3) +
4*a_i**2*k0 + 4*a_i**2*k3),
(
a**3*(-k0 - k1 + k2 + k3) +
a**2*(4*I*a_i*k0 + 2*I*a_i*k1 - 2*I*a_i*k2 - 4*I*a_i*k3) +
a*(4*a_i**2*k0 - 4*a_i**2*k3))
]
dc = [
S.One, S.Zero, 2*a_i**2 - 2*a_r**2,
S.Zero, a_i**4 + 2*a_i**2*a_r**2 + a_r**4]
n = Add(
*[x*s**y for x, y in zip(_simpc(nc), range(len(nc))[::-1])])
d = Add(
*[x*s**y for x, y in zip(dc, range(len(dc))[::-1])])
return n/d
def _ccpole(t1, k1, s):
a, k0, a_r, a_i = t1['a'], t1['k'], t1[re], t1[im]
nc = [k0 + k1, -a*k0 - a*k1 + 2*I*a_i*k0]
dc = [S.One, -2*a_r, a_i**2 + a_r**2]
n = Add(
*[x*s**y for x, y in zip(_simpc(nc), range(len(nc))[::-1])])
d = Add(
*[x*s**y for x, y in zip(dc, range(len(dc))[::-1])])
return n/d
def _rspole(t1, k2, s):
a, k0, a_r, a_i = t1['a'], t1['k'], t1[re], t1[im]
nc = [k0 + k2, a*k0 - a*k2 - 2*I*a_i*k0]
dc = [S.One, -2*I*a_i, -a_i**2 - a_r**2]
n = Add(
*[x*s**y for x, y in zip(_simpc(nc), range(len(nc))[::-1])])
d = Add(
*[x*s**y for x, y in zip(dc, range(len(dc))[::-1])])
return n/d
def _sypole(t1, k3, s):
a, k0 = t1['a'], t1['k']
nc = [k0 + k3, a*(k0 - k3)]
dc = [S.One, S.Zero, -a**2]
n = Add(
*[x*s**y for x, y in zip(_simpc(nc), range(len(nc))[::-1])])
d = Add(
*[x*s**y for x, y in zip(dc, range(len(dc))[::-1])])
return n/d
def _simplepole(t1, s):
a, k0 = t1['a'], t1['k']
n = k0
d = s - a
return n/d
while len(xm) > 0:
t1 = xm.pop()
i_imagsym = None
i_realsym = None
i_pointsym = None
# The following code checks all remaining poles. If t1 is a pole at
# a+b*I, then we check for a-b*I, -a+b*I, and -a-b*I, and
# assign the respective indices to i_imagsym, i_realsym, i_pointsym.
# -a-b*I / i_pointsym only applies if both a and b are != 0.
for i in range(len(xm)):
real_eq = t1[re] == xm[i][re]
realsym = t1[re] == -xm[i][re]
imag_eq = t1[im] == xm[i][im]
imagsym = t1[im] == -xm[i][im]
if realsym and imagsym and t1[re] != 0 and t1[im] != 0:
i_pointsym = i
elif realsym and imag_eq and t1[re] != 0:
i_realsym = i
elif real_eq and imagsym and t1[im] != 0:
i_imagsym = i
# The next part looks for four possible pole constellations:
# quad: a+b*I, a-b*I, -a+b*I, -a-b*I
# cc: a+b*I, a-b*I (a may be zero)
# quad: a+b*I, -a+b*I (b may be zero)
# point: a+b*I, -a-b*I (a!=0 and b!=0 is needed, but that has been
# asserted when finding i_pointsym above.)
# If none apply, then t1 is a simple pole.
if (
i_imagsym is not None and i_realsym is not None
and i_pointsym is not None):
results.append(
_quadpole(t1,
xm[i_imagsym]['k'], xm[i_realsym]['k'],
xm[i_pointsym]['k'], s))
planes.append(Abs(re(t1['a'])))
# The three additional poles have now been used; to pop them
# easily we have to do it from the back.
indices_to_pop = [i_imagsym, i_realsym, i_pointsym]
indices_to_pop.sort(reverse=True)
for i in indices_to_pop:
xm.pop(i)
elif i_imagsym is not None:
results.append(_ccpole(t1, xm[i_imagsym]['k'], s))
planes.append(t1[re])
xm.pop(i_imagsym)
elif i_realsym is not None:
results.append(_rspole(t1, xm[i_realsym]['k'], s))
planes.append(Abs(t1[re]))
xm.pop(i_realsym)
elif i_pointsym is not None:
results.append(_sypole(t1, xm[i_pointsym]['k'], s))
planes.append(Abs(t1[re]))
xm.pop(i_pointsym)
else:
results.append(_simplepole(t1, s))
planes.append(t1[re])
return Add(*results), Max(*planes)
@DEBUG_WRAP
def _laplace_rule_trig(fn, t_, s):
"""
This rule covers trigonometric factors by splitting everything into a
sum of exponential functions and collecting complex conjugate poles and
real symmetric poles.
"""
t = Dummy('t', real=True)
if not fn.has(sin, cos, sinh, cosh):
return None
f, g = _laplace_trig_split(fn.subs(t_, t))
xm, xn = _laplace_trig_expsum(f, t)
if len(xn) > 0:
# TODO not implemented yet, but also not important
return None
if not g.has(t):
r, p = _laplace_trig_ltex(xm, t, s)
return g*r, p, S.true
else:
# Just transform `g` and make frequency-shifted copies
planes = []
results = []
G, G_plane, G_cond = _laplace_transform(g, t, s, simplify=False)
for x1 in xm:
results.append(x1['k']*G.subs(s, s-x1['a']))
planes.append(G_plane+re(x1['a']))
return Add(*results).subs(t, t_), Max(*planes), G_cond
@DEBUG_WRAP
def _laplace_rule_diff(f, t, s):
"""
This function looks for derivatives in the time domain and replaces it
by factors of `s` and initial conditions in the frequency domain. For
example, if it gets ``(diff(f(t), t), t, s)``, it will compute
``s*LaplaceTransform(f(t), t, s) - f(0)``.
"""
a = Wild('a', exclude=[t])
n = Wild('n', exclude=[t])
g = WildFunction('g')
ma1 = f.match(a*Derivative(g, (t, n)))
if ma1 and ma1[n].is_integer:
m = [z.has(t) for z in ma1[g].args]
if sum(m) == 1:
_debug(' rule: time derivative (4.1.8)')
d = []
for k in range(ma1[n]):
if k == 0:
y = ma1[g].subs(t, 0)
else:
y = Derivative(ma1[g], (t, k)).subs(t, 0)
d.append(s**(ma1[n]-k-1)*y)
r, pr, cr = _laplace_transform(ma1[g], t, s, simplify=False)
return (ma1[a]*(s**ma1[n]*r - Add(*d)), pr, cr)
return None
@DEBUG_WRAP
def _laplace_rule_sdiff(f, t, s):
"""
This function looks for multiplications with polynoimials in `t` as they
correspond to differentiation in the frequency domain. For example, if it
gets ``(t*f(t), t, s)``, it will compute
``-Derivative(LaplaceTransform(f(t), t, s), s)``.
"""
if f.is_Mul:
pfac = [1]
ofac = [1]
for fac in Mul.make_args(f):
if fac.is_polynomial(t):
pfac.append(fac)
else:
ofac.append(fac)
if len(pfac) > 1:
pex = prod(pfac)
pc = Poly(pex, t).all_coeffs()
N = len(pc)
if N > 1:
oex = prod(ofac)
r_, p_, c_ = _laplace_transform(oex, t, s, simplify=False)
deri = [r_]
d1 = False
try:
d1 = -diff(deri[-1], s)
except ValueError:
d1 = False
if r_.has(LaplaceTransform):
for k in range(N-1):
deri.append((-1)**(k+1)*Derivative(r_, s, k+1))
elif d1:
deri.append(d1)
for k in range(N-2):
deri.append(-diff(deri[-1], s))
if d1:
r = Add(*[pc[N-n-1]*deri[n] for n in range(N)])
return (r, p_, c_)
# We still have to cover the possibility that there is a symbolic positive
# integer exponent.
n = Wild('n', exclude=[t])
g = Wild('g')
if ma1 := f.match(t**n*g):
if ma1[n].is_integer and ma1[n].is_positive:
r_, p_, c_ = _laplace_transform(ma1[g], t, s, simplify=False)
return (-1)**ma1[n]*diff(r_, (s, ma1[n])), p_, c_
return None
@DEBUG_WRAP
def _laplace_expand(f, t, s):
"""
This function tries to expand its argument with successively stronger
methods: first it will expand on the top level, then it will expand any
multiplications in depth, then it will try all avilable expansion methods,
and finally it will try to expand trigonometric functions.
If it can expand, it will then compute the Laplace transform of the
expanded term.
"""
r = expand(f, deep=False)
if r.is_Add:
return _laplace_transform(r, t, s, simplify=False)
r = expand_mul(f)
if r.is_Add:
return _laplace_transform(r, t, s, simplify=False)
r = expand(f)
if r.is_Add:
return _laplace_transform(r, t, s, simplify=False)
if r != f:
return _laplace_transform(r, t, s, simplify=False)
r = expand(expand_trig(f))
if r.is_Add:
return _laplace_transform(r, t, s, simplify=False)
return None
@DEBUG_WRAP
def _laplace_apply_prog_rules(f, t, s):
"""
This function applies all program rules and returns the result if one
of them gives a result.
"""
prog_rules = [_laplace_rule_heaviside, _laplace_rule_delta,
_laplace_rule_timescale, _laplace_rule_exp,
_laplace_rule_trig,
_laplace_rule_diff, _laplace_rule_sdiff]
for p_rule in prog_rules:
if (L := p_rule(f, t, s)) is not None:
return L
return None
@DEBUG_WRAP
def _laplace_apply_simple_rules(f, t, s):
"""
This function applies all simple rules and returns the result if one
of them gives a result.
"""
simple_rules, t_, s_ = _laplace_build_rules()
prep_old = ''
prep_f = ''
for t_dom, s_dom, check, plane, prep in simple_rules:
if prep_old != prep:
prep_f = prep(f.subs({t: t_}))
prep_old = prep
ma = prep_f.match(t_dom)
if ma:
try:
c = check.xreplace(ma)
except TypeError:
# This may happen if the time function has imaginary
# numbers in it. Then we give up.
continue
if c == S.true:
return (s_dom.xreplace(ma).subs({s_: s}),
plane.xreplace(ma), S.true)
return None
@DEBUG_WRAP
def _piecewise_to_heaviside(f, t):
"""
This function converts a Piecewise expression to an expression written
with Heaviside. It is not exact, but valid in the context of the Laplace
transform.
"""
if not t.is_real:
r = Dummy('r', real=True)
return _piecewise_to_heaviside(f.xreplace({t: r}), r).xreplace({r: t})
x = piecewise_exclusive(f)
r = []
for fn, cond in x.args:
# Here we do not need to do many checks because piecewise_exclusive
# has a clearly predictable output. However, if any of the conditions
# is not relative to t, this function just returns the input argument.
if isinstance(cond, Relational) and t in cond.args:
if isinstance(cond, (Eq, Ne)):
# We do not cover this case; these would be single-point
# exceptions that do not play a role in Laplace practice,
# except if they contain Dirac impulses, and then we can
# expect users to not try to use Piecewise for writing it.
return f
else:
r.append(Heaviside(cond.gts - cond.lts)*fn)
elif isinstance(cond, Or) and len(cond.args) == 2:
# Or(t<2, t>4), Or(t>4, t<=2), ... in any order with any <= >=
for c2 in cond.args:
if c2.lhs == t:
r.append(Heaviside(c2.gts - c2.lts)*fn)
else:
return f
elif isinstance(cond, And) and len(cond.args) == 2:
# And(t>2, t<4), And(t>4, t<=2), ... in any order with any <= >=
c0, c1 = cond.args
if c0.lhs == t and c1.lhs == t:
if '>' in c0.rel_op:
c0, c1 = c1, c0
r.append(
(Heaviside(c1.gts - c1.lts) -
Heaviside(c0.lts - c0.gts))*fn)
else:
return f
else:
return f
return Add(*r)
def laplace_correspondence(f, fdict, /):
"""
This helper function takes a function `f` that is the result of a
``laplace_transform`` or an ``inverse_laplace_transform``. It replaces all
unevaluated ``LaplaceTransform(y(t), t, s)`` by `Y(s)` for any `s` and
all ``InverseLaplaceTransform(Y(s), s, t)`` by `y(t)` for any `t` if
``fdict`` contains a correspondence ``{y: Y}``.
Parameters
==========
f : sympy expression
Expression containing unevaluated ``LaplaceTransform`` or
``LaplaceTransform`` objects.
fdict : dictionary
Dictionary containing one or more function correspondences,
e.g., ``{x: X, y: Y}`` meaning that ``X`` and ``Y`` are the
Laplace transforms of ``x`` and ``y``, respectively.
Examples
========
>>> from sympy import laplace_transform, diff, Function
>>> from sympy import laplace_correspondence, inverse_laplace_transform
>>> from sympy.abc import t, s
>>> y = Function("y")
>>> Y = Function("Y")
>>> z = Function("z")
>>> Z = Function("Z")
>>> f = laplace_transform(diff(y(t), t, 1) + z(t), t, s, noconds=True)
>>> laplace_correspondence(f, {y: Y, z: Z})
s*Y(s) + Z(s) - y(0)
>>> f = inverse_laplace_transform(Y(s), s, t)
>>> laplace_correspondence(f, {y: Y})
y(t)
"""
p = Wild('p')
s = Wild('s')
t = Wild('t')
a = Wild('a')
if (
not isinstance(f, Expr)
or (not f.has(LaplaceTransform)
and not f.has(InverseLaplaceTransform))):
return f
for y, Y in fdict.items():
if (
(m := f.match(LaplaceTransform(y(a), t, s))) is not None
and m[a] == m[t]):
return Y(m[s])
if (
(m := f.match(InverseLaplaceTransform(Y(a), s, t, p)))
is not None
and m[a] == m[s]):
return y(m[t])
func = f.func
args = [laplace_correspondence(arg, fdict) for arg in f.args]
return func(*args)
def laplace_initial_conds(f, t, fdict, /):
"""
This helper function takes a function `f` that is the result of a
``laplace_transform``. It takes an fdict of the form ``{y: [1, 4, 2]}``,
where the values in the list are the initial value, the initial slope, the
initial second derivative, etc., of the function `y(t)`, and replaces all
unevaluated initial conditions.
Parameters
==========
f : sympy expression
Expression containing initial conditions of unevaluated functions.
t : sympy expression
Variable for which the initial conditions are to be applied.
fdict : dictionary
Dictionary containing a list of initial conditions for every
function, e.g., ``{y: [0, 1, 2], x: [3, 4, 5]}``. The order
of derivatives is ascending, so `0`, `1`, `2` are `y(0)`, `y'(0)`,
and `y''(0)`, respectively.
Examples
========
>>> from sympy import laplace_transform, diff, Function
>>> from sympy import laplace_correspondence, laplace_initial_conds
>>> from sympy.abc import t, s
>>> y = Function("y")
>>> Y = Function("Y")
>>> f = laplace_transform(diff(y(t), t, 3), t, s, noconds=True)
>>> g = laplace_correspondence(f, {y: Y})
>>> laplace_initial_conds(g, t, {y: [2, 4, 8, 16, 32]})
s**3*Y(s) - 2*s**2 - 4*s - 8
"""
for y, ic in fdict.items():
for k in range(len(ic)):
if k == 0:
f = f.replace(y(0), ic[0])
elif k == 1:
f = f.replace(Subs(Derivative(y(t), t), t, 0), ic[1])
else:
f = f.replace(Subs(Derivative(y(t), (t, k)), t, 0), ic[k])
return f
@DEBUG_WRAP
def _laplace_transform(fn, t_, s_, *, simplify):
"""
Front-end function of the Laplace transform. It tries to apply all known
rules recursively, and if everything else fails, it tries to integrate.
"""
terms_t = Add.make_args(fn)
terms_s = []
terms = []
planes = []
conditions = []
for ff in terms_t:
k, ft = ff.as_independent(t_, as_Add=False)
if ft.has(SingularityFunction):
_terms = Add.make_args(ft.rewrite(Heaviside))
for _term in _terms:
k1, f1 = _term.as_independent(t_, as_Add=False)
terms.append((k*k1, f1))
elif ft.func == Piecewise and not ft.has(DiracDelta(t_)):
_terms = Add.make_args(_piecewise_to_heaviside(ft, t_))
for _term in _terms:
k1, f1 = _term.as_independent(t_, as_Add=False)
terms.append((k*k1, f1))
else:
terms.append((k, ft))
for k, ft in terms:
if ft.has(SingularityFunction):
r = (LaplaceTransform(ft, t_, s_), S.NegativeInfinity, True)
else:
if ft.has(Heaviside(t_)) and not ft.has(DiracDelta(t_)):
# For t>=0, Heaviside(t)=1 can be used, except if there is also
# a DiracDelta(t) present, in which case removing Heaviside(t)
# is unnecessary because _laplace_rule_delta can deal with it.
ft = ft.subs(Heaviside(t_), 1)
if (
(r := _laplace_apply_simple_rules(ft, t_, s_))
is not None or
(r := _laplace_apply_prog_rules(ft, t_, s_))
is not None or
(r := _laplace_expand(ft, t_, s_)) is not None):
pass
elif any(undef.has(t_) for undef in ft.atoms(AppliedUndef)):
# If there are undefined functions f(t) then integration is
# unlikely to do anything useful so we skip it and given an
# unevaluated LaplaceTransform.
r = (LaplaceTransform(ft, t_, s_), S.NegativeInfinity, True)
elif (r := _laplace_transform_integration(
ft, t_, s_, simplify=simplify)) is not None:
pass
else:
r = (LaplaceTransform(ft, t_, s_), S.NegativeInfinity, True)
(ri_, pi_, ci_) = r
terms_s.append(k*ri_)
planes.append(pi_)
conditions.append(ci_)
result = Add(*terms_s)
if simplify:
result = result.simplify(doit=False)
plane = Max(*planes)
condition = And(*conditions)
return result, plane, condition
class LaplaceTransform(IntegralTransform):
"""
Class representing unevaluated Laplace transforms.
For usage of this class, see the :class:`IntegralTransform` docstring.
For how to compute Laplace transforms, see the :func:`laplace_transform`
docstring.
If this is called with ``.doit()``, it returns the Laplace transform as an
expression. If it is called with ``.doit(noconds=False)``, it returns a
tuple containing the same expression, a convergence plane, and conditions.
"""
_name = 'Laplace'
def _compute_transform(self, f, t, s, **hints):
_simplify = hints.get('simplify', False)
LT = _laplace_transform_integration(f, t, s, simplify=_simplify)
return LT
def _as_integral(self, f, t, s):
return Integral(f*exp(-s*t), (t, S.Zero, S.Infinity))
def doit(self, **hints):
"""
Try to evaluate the transform in closed form.
Explanation
===========
Standard hints are the following:
- ``noconds``: if True, do not return convergence conditions. The
default setting is `True`.
- ``simplify``: if True, it simplifies the final result. The
default setting is `False`.
"""
_noconds = hints.get('noconds', True)
_simplify = hints.get('simplify', False)
debugf('[LT doit] (%s, %s, %s)', (self.function,
self.function_variable,
self.transform_variable))
t_ = self.function_variable
s_ = self.transform_variable
fn = self.function
r = _laplace_transform(fn, t_, s_, simplify=_simplify)
if _noconds:
return r[0]
else:
return r
def laplace_transform(f, t, s, legacy_matrix=True, **hints):
r"""
Compute the Laplace Transform `F(s)` of `f(t)`,
.. math :: F(s) = \int_{0^{-}}^\infty e^{-st} f(t) \mathrm{d}t.
Explanation
===========
For all sensible functions, this converges absolutely in a
half-plane
.. math :: a < \operatorname{Re}(s)
This function returns ``(F, a, cond)`` where ``F`` is the Laplace
transform of ``f``, `a` is the half-plane of convergence, and `cond` are
auxiliary convergence conditions.
The implementation is rule-based, and if you are interested in which
rules are applied, and whether integration is attempted, you can switch
debug information on by setting ``sympy.SYMPY_DEBUG=True``. The numbers
of the rules in the debug information (and the code) refer to Bateman's
Tables of Integral Transforms [1].
The lower bound is `0-`, meaning that this bound should be approached
from the lower side. This is only necessary if distributions are involved.
At present, it is only done if `f(t)` contains ``DiracDelta``, in which
case the Laplace transform is computed implicitly as
.. math ::
F(s) = \lim_{\tau\to 0^{-}} \int_{\tau}^\infty e^{-st}
f(t) \mathrm{d}t
by applying rules.
If the Laplace transform cannot be fully computed in closed form, this
function returns expressions containing unevaluated
:class:`LaplaceTransform` objects.
For a description of possible hints, refer to the docstring of
:func:`sympy.integrals.transforms.IntegralTransform.doit`. If
``noconds=True``, only `F` will be returned (i.e. not ``cond``, and also
not the plane ``a``).
.. deprecated:: 1.9
Legacy behavior for matrices where ``laplace_transform`` with
``noconds=False`` (the default) returns a Matrix whose elements are
tuples. The behavior of ``laplace_transform`` for matrices will change
in a future release of SymPy to return a tuple of the transformed
Matrix and the convergence conditions for the matrix as a whole. Use
``legacy_matrix=False`` to enable the new behavior.
Examples
========
>>> from sympy import DiracDelta, exp, laplace_transform
>>> from sympy.abc import t, s, a
>>> laplace_transform(t**4, t, s)
(24/s**5, 0, True)
>>> laplace_transform(t**a, t, s)
(gamma(a + 1)/(s*s**a), 0, re(a) > -1)
>>> laplace_transform(DiracDelta(t)-a*exp(-a*t), t, s, simplify=True)
(s/(a + s), -re(a), True)
There are also helper functions that make it easy to solve differential
equations by Laplace transform. For example, to solve
.. math :: m x''(t) + d x'(t) + k x(t) = 0
with initial value `0` and initial derivative `v`:
>>> from sympy import Function, laplace_correspondence, diff, solve
>>> from sympy import laplace_initial_conds, inverse_laplace_transform
>>> from sympy.abc import d, k, m, v
>>> x = Function('x')
>>> X = Function('X')
>>> f = m*diff(x(t), t, 2) + d*diff(x(t), t) + k*x(t)
>>> F = laplace_transform(f, t, s, noconds=True)
>>> F = laplace_correspondence(F, {x: X})
>>> F = laplace_initial_conds(F, t, {x: [0, v]})
>>> F
d*s*X(s) + k*X(s) + m*(s**2*X(s) - v)
>>> Xs = solve(F, X(s))[0]
>>> Xs
m*v/(d*s + k + m*s**2)
>>> inverse_laplace_transform(Xs, s, t)
2*v*exp(-d*t/(2*m))*sin(t*sqrt((-d**2 + 4*k*m)/m**2)/2)*Heaviside(t)/sqrt((-d**2 + 4*k*m)/m**2)
References
==========
.. [1] Erdelyi, A. (ed.), Tables of Integral Transforms, Volume 1,
Bateman Manuscript Prooject, McGraw-Hill (1954), available:
https://resolver.caltech.edu/CaltechAUTHORS:20140123-101456353
See Also
========
inverse_laplace_transform, mellin_transform, fourier_transform
hankel_transform, inverse_hankel_transform
"""
_noconds = hints.get('noconds', False)
_simplify = hints.get('simplify', False)
if isinstance(f, MatrixBase) and hasattr(f, 'applyfunc'):
conds = not hints.get('noconds', False)
if conds and legacy_matrix:
adt = 'deprecated-laplace-transform-matrix'
sympy_deprecation_warning(
"""
Calling laplace_transform() on a Matrix with noconds=False (the default) is
deprecated. Either noconds=True or use legacy_matrix=False to get the new
behavior.
""",
deprecated_since_version='1.9',
active_deprecations_target=adt,
)
# Temporarily disable the deprecation warning for non-Expr objects
# in Matrix
with ignore_warnings(SymPyDeprecationWarning):
return f.applyfunc(
lambda fij: laplace_transform(fij, t, s, **hints))
else:
elements_trans = [laplace_transform(
fij, t, s, **hints) for fij in f]
if conds:
elements, avals, conditions = zip(*elements_trans)
f_laplace = type(f)(*f.shape, elements)
return f_laplace, Max(*avals), And(*conditions)
else:
return type(f)(*f.shape, elements_trans)
LT, p, c = LaplaceTransform(f, t, s).doit(noconds=False,
simplify=_simplify)
if not _noconds:
return LT, p, c
else:
return LT
@DEBUG_WRAP
def _inverse_laplace_transform_integration(F, s, t_, plane, *, simplify):
""" The backend function for inverse Laplace transforms. """
from sympy.integrals.meijerint import meijerint_inversion, _get_coeff_exp
from sympy.integrals.transforms import inverse_mellin_transform
# There are two strategies we can try:
# 1) Use inverse mellin transform, related by a simple change of variables.
# 2) Use the inversion integral.
t = Dummy('t', real=True)
def pw_simp(*args):
""" Simplify a piecewise expression from hyperexpand. """
if len(args) != 3:
return Piecewise(*args)
arg = args[2].args[0].argument
coeff, exponent = _get_coeff_exp(arg, t)
e1 = args[0].args[0]
e2 = args[1].args[0]
return (
Heaviside(1/Abs(coeff) - t**exponent)*e1 +
Heaviside(t**exponent - 1/Abs(coeff))*e2)
if F.is_rational_function(s):
F = F.apart(s)
if F.is_Add:
f = Add(
*[_inverse_laplace_transform_integration(X, s, t, plane, simplify)
for X in F.args])
return _simplify(f.subs(t, t_), simplify), True
try:
f, cond = inverse_mellin_transform(F, s, exp(-t), (None, S.Infinity),
needeval=True, noconds=False)
except IntegralTransformError:
f = None
if f is None:
f = meijerint_inversion(F, s, t)
if f is None:
return None
if f.is_Piecewise:
f, cond = f.args[0]
if f.has(Integral):
return None
else:
cond = S.true
f = f.replace(Piecewise, pw_simp)
if f.is_Piecewise:
# many of the functions called below can't work with piecewise
# (b/c it has a bool in args)
return f.subs(t, t_), cond
u = Dummy('u')
def simp_heaviside(arg, H0=S.Half):
a = arg.subs(exp(-t), u)
if a.has(t):
return Heaviside(arg, H0)
from sympy.solvers.inequalities import _solve_inequality
rel = _solve_inequality(a > 0, u)
if rel.lts == u:
k = log(rel.gts)
return Heaviside(t + k, H0)
else:
k = log(rel.lts)
return Heaviside(-(t + k), H0)
f = f.replace(Heaviside, simp_heaviside)
def simp_exp(arg):
return expand_complex(exp(arg))
f = f.replace(exp, simp_exp)
return _simplify(f.subs(t, t_), simplify), cond
@DEBUG_WRAP
def _complete_the_square_in_denom(f, s):
from sympy.simplify.radsimp import fraction
[n, d] = fraction(f)
if d.is_polynomial(s):
cf = d.as_poly(s).all_coeffs()
if len(cf) == 3:
a, b, c = cf
d = a*((s+b/(2*a))**2+c/a-(b/(2*a))**2)
return n/d
@cacheit
def _inverse_laplace_build_rules():
"""
This is an internal helper function that returns the table of inverse
Laplace transform rules in terms of the time variable `t` and the
frequency variable `s`. It is used by `_inverse_laplace_apply_rules`.
"""
s = Dummy('s')
t = Dummy('t')
a = Wild('a', exclude=[s])
b = Wild('b', exclude=[s])
c = Wild('c', exclude=[s])
_debug('_inverse_laplace_build_rules is building rules')
def _frac(f, s):
try:
return f.factor(s)
except PolynomialError:
return f
def same(f): return f
# This list is sorted according to the prep function needed.
_ILT_rules = [
(a/s, a, S.true, same, 1),
(
b*(s+a)**(-c), t**(c-1)*exp(-a*t)/gamma(c),
S.true, same, 1),
(1/(s**2+a**2)**2, (sin(a*t) - a*t*cos(a*t))/(2*a**3),
S.true, same, 1),
# The next two rules must be there in that order. For the second
# one, the condition would be a != 0 or, respectively, to take the
# limit a -> 0 after the transform if a == 0. It is much simpler if
# the case a == 0 has its own rule.
(1/(s**b), t**(b - 1)/gamma(b), S.true, same, 1),
(1/(s*(s+a)**b), lowergamma(b, a*t)/(a**b*gamma(b)),
S.true, same, 1)
]
return _ILT_rules, s, t
@DEBUG_WRAP
def _inverse_laplace_apply_simple_rules(f, s, t):
"""
Helper function for the class InverseLaplaceTransform.
"""
if f == 1:
_debug(' rule: 1 o---o DiracDelta()')
return DiracDelta(t), S.true
_ILT_rules, s_, t_ = _inverse_laplace_build_rules()
_prep = ''
fsubs = f.subs({s: s_})
for s_dom, t_dom, check, prep, fac in _ILT_rules:
if _prep != (prep, fac):
_F = prep(fsubs*fac)
_prep = (prep, fac)
ma = _F.match(s_dom)
if ma:
c = check
if c is not S.true:
args = [x.xreplace(ma) for x in c[0]]
c = c[1](*args)
if c == S.true:
return Heaviside(t)*t_dom.xreplace(ma).subs({t_: t}), S.true
return None
@DEBUG_WRAP
def _inverse_laplace_diff(f, s, t, plane):
"""
Helper function for the class InverseLaplaceTransform.
"""
a = Wild('a', exclude=[s])
n = Wild('n', exclude=[s])
g = Wild('g')
ma = f.match(a*Derivative(g, (s, n)))
if ma and ma[n].is_integer:
_debug(' rule: t**n*f(t) o---o (-1)**n*diff(F(s), s, n)')
r, c = _inverse_laplace_transform(
ma[g], s, t, plane, simplify=False, dorational=False)
return (-t)**ma[n]*r, c
return None
@DEBUG_WRAP
def _inverse_laplace_time_shift(F, s, t, plane):
"""
Helper function for the class InverseLaplaceTransform.
"""
a = Wild('a', exclude=[s])
g = Wild('g')
if not F.has(s):
return F*DiracDelta(t), S.true
if not F.has(exp):
return None
ma1 = F.match(exp(a*s))
if ma1:
if ma1[a].is_negative:
_debug(' rule: exp(-a*s) o---o DiracDelta(t-a)')
return DiracDelta(t+ma1[a]), S.true
else:
return InverseLaplaceTransform(F, s, t, plane), S.true
ma1 = F.match(exp(a*s)*g)
if ma1:
if ma1[a].is_negative:
_debug(' rule: exp(-a*s)*F(s) o---o Heaviside(t-a)*f(t-a)')
return _inverse_laplace_transform(
ma1[g], s, t+ma1[a], plane, simplify=False, dorational=True)
else:
return InverseLaplaceTransform(F, s, t, plane), S.true
return None
@DEBUG_WRAP
def _inverse_laplace_freq_shift(F, s, t, plane):
"""
Helper function for the class InverseLaplaceTransform.
"""
if not F.has(s):
return F*DiracDelta(t), S.true
if len(args := F.args) == 1:
a = Wild('a', exclude=[s])
if (ma := args[0].match(s-a)) and re(ma[a]).is_positive:
_debug(' rule: F(s-a) o---o exp(-a*t)*f(t)')
return (
exp(-ma[a]*t) *
InverseLaplaceTransform(F.func(s), s, t, plane), S.true)
return None
@DEBUG_WRAP
def _inverse_laplace_time_diff(F, s, t, plane):
"""
Helper function for the class InverseLaplaceTransform.
"""
n = Wild('n', exclude=[s])
g = Wild('g')
ma1 = F.match(s**n*g)
if ma1 and ma1[n].is_integer and ma1[n].is_positive:
_debug(' rule: s**n*F(s) o---o diff(f(t), t, n)')
r, c = _inverse_laplace_transform(
ma1[g], s, t, plane, simplify=False, dorational=True)
r = r.replace(Heaviside(t), 1)
if r.has(InverseLaplaceTransform):
return diff(r, t, ma1[n]), c
else:
return Heaviside(t)*diff(r, t, ma1[n]), c
return None
@DEBUG_WRAP
def _inverse_laplace_irrational(fn, s, t, plane):
"""
Helper function for the class InverseLaplaceTransform.
"""
a = Wild('a', exclude=[s])
b = Wild('b', exclude=[s])
m = Wild('m', exclude=[s])
n = Wild('n', exclude=[s])
result = None
condition = S.true
fa = fn.as_ordered_factors()
ma = [x.match((a*s**m+b)**n) for x in fa]
if None in ma:
return None
constants = S.One
zeros = []
poles = []
rest = []
for term in ma:
if term[a] == 0:
constants = constants*term
elif term[n].is_positive:
zeros.append(term)
elif term[n].is_negative:
poles.append(term)
else:
rest.append(term)
# The code below assumes that the poles are sorted in a specific way:
poles = sorted(poles, key=lambda x: (x[n], x[b] != 0, x[b]))
zeros = sorted(zeros, key=lambda x: (x[n], x[b] != 0, x[b]))
if len(rest) != 0:
return None
if len(poles) == 1 and len(zeros) == 0:
if poles[0][n] == -1 and poles[0][m] == S.Half:
# 1/(a0*sqrt(s)+b0) == 1/a0 * 1/(sqrt(s)+b0/a0)
a_ = poles[0][b]/poles[0][a]
k_ = 1/poles[0][a]*constants
if a_.is_positive:
result = (
k_/sqrt(pi)/sqrt(t) -
k_*a_*exp(a_**2*t)*erfc(a_*sqrt(t)))
_debug(' rule 5.3.4')
elif poles[0][n] == -2 and poles[0][m] == S.Half:
# 1/(a0*sqrt(s)+b0)**2 == 1/a0**2 * 1/(sqrt(s)+b0/a0)**2
a_sq = poles[0][b]/poles[0][a]
a_ = a_sq**2
k_ = 1/poles[0][a]**2*constants
if a_sq.is_positive:
result = (
k_*(1 - 2/sqrt(pi)*sqrt(a_)*sqrt(t) +
(1-2*a_*t)*exp(a_*t)*(erf(sqrt(a_)*sqrt(t))-1)))
_debug(' rule 5.3.10')
elif poles[0][n] == -3 and poles[0][m] == S.Half:
# 1/(a0*sqrt(s)+b0)**3 == 1/a0**3 * 1/(sqrt(s)+b0/a0)**3
a_ = poles[0][b]/poles[0][a]
k_ = 1/poles[0][a]**3*constants
if a_.is_positive:
result = (
k_*(2/sqrt(pi)*(a_**2*t+1)*sqrt(t) -
a_*t*exp(a_**2*t)*(2*a_**2*t+3)*erfc(a_*sqrt(t))))
_debug(' rule 5.3.13')
elif poles[0][n] == -4 and poles[0][m] == S.Half:
# 1/(a0*sqrt(s)+b0)**4 == 1/a0**4 * 1/(sqrt(s)+b0/a0)**4
a_ = poles[0][b]/poles[0][a]
k_ = 1/poles[0][a]**4*constants/3
if a_.is_positive:
result = (
k_*(t*(4*a_**4*t**2+12*a_**2*t+3)*exp(a_**2*t) *
erfc(a_*sqrt(t)) -
2/sqrt(pi)*a_**3*t**(S(5)/2)*(2*a_**2*t+5)))
_debug(' rule 5.3.16')
elif poles[0][n] == -S.Half and poles[0][m] == 2:
# 1/sqrt(a0*s**2+b0) == 1/sqrt(a0) * 1/sqrt(s**2+b0/a0)
a_ = sqrt(poles[0][b]/poles[0][a])
k_ = 1/sqrt(poles[0][a])*constants
result = (k_*(besselj(0, a_*t)))
_debug(' rule 5.3.35/44')
elif len(poles) == 1 and len(zeros) == 1:
if (
poles[0][n] == -3 and poles[0][m] == S.Half and
zeros[0][n] == S.Half and zeros[0][b] == 0):
# sqrt(az*s)/(ap*sqrt(s+bp)**3)
# == sqrt(az)/ap * sqrt(s)/(sqrt(s+bp)**3)
a_ = poles[0][b]
k_ = sqrt(zeros[0][a])/poles[0][a]*constants
result = (
k_*(2*a_**4*t**2+5*a_**2*t+1)*exp(a_**2*t) *
erfc(a_*sqrt(t)) - 2/sqrt(pi)*a_*(a_**2*t+2)*sqrt(t))
_debug(' rule 5.3.14')
if (
poles[0][n] == -1 and poles[0][m] == 1 and
zeros[0][n] == S.Half and zeros[0][m] == 1):
# sqrt(az*s+bz)/(ap*s+bp)
# == sqrt(az)/ap * (sqrt(s+bz/az)/(s+bp/ap))
a_ = zeros[0][b]/zeros[0][a]
b_ = poles[0][b]/poles[0][a]
k_ = sqrt(zeros[0][a])/poles[0][a]*constants
result = (
k_*(exp(-a_*t)/sqrt(t)/sqrt(pi)+sqrt(a_-b_) *
exp(-b_*t)*erf(sqrt(a_-b_)*sqrt(t))))
_debug(' rule 5.3.22')
elif len(poles) == 2 and len(zeros) == 0:
if (
poles[0][n] == -1 and poles[0][m] == 1 and
poles[1][n] == -S.Half and poles[1][m] == 1 and
poles[1][b] == 0):
# 1/((a0*s+b0)*sqrt(a1*s))
# == 1/(a0*sqrt(a1)) * 1/((s+b0/a0)*sqrt(s))
a_ = -poles[0][b]/poles[0][a]
k_ = 1/sqrt(poles[1][a])/poles[0][a]*constants
if a_.is_positive:
result = (k_/sqrt(a_)*exp(a_*t)*erf(sqrt(a_)*sqrt(t)))
_debug(' rule 5.3.1')
elif (
poles[0][n] == -1 and poles[0][m] == 1 and poles[0][b] == 0 and
poles[1][n] == -1 and poles[1][m] == S.Half):
# 1/(a0*s*(a1*sqrt(s)+b1))
# == 1/(a0*a1) * 1/(s*(sqrt(s)+b1/a1))
a_ = poles[1][b]/poles[1][a]
k_ = 1/poles[0][a]/poles[1][a]/a_*constants
if a_.is_positive:
result = k_*(1-exp(a_**2*t)*erfc(a_*sqrt(t)))
_debug(' rule 5.3.5')
elif (
poles[0][n] == -1 and poles[0][m] == S.Half and
poles[1][n] == -S.Half and poles[1][m] == 1 and
poles[1][b] == 0):
# 1/((a0*sqrt(s)+b0)*(sqrt(a1*s))
# == 1/(a0*sqrt(a1)) * 1/((sqrt(s)+b0/a0)"sqrt(s))
a_ = poles[0][b]/poles[0][a]
k_ = 1/(poles[0][a]*sqrt(poles[1][a]))*constants
if a_.is_positive:
result = k_*exp(a_**2*t)*erfc(a_*sqrt(t))
_debug(' rule 5.3.7')
elif (
poles[0][n] == -S(3)/2 and poles[0][m] == 1 and
poles[0][b] == 0 and poles[1][n] == -1 and
poles[1][m] == S.Half):
# 1/((a0**(3/2)*s**(3/2))*(a1*sqrt(s)+b1))
# == 1/(a0**(3/2)*a1) 1/((s**(3/2))*(sqrt(s)+b1/a1))
# Note that Bateman54 5.3 (8) is incorrect; there (sqrt(p)+a)
# should be (sqrt(p)+a)**(-1).
a_ = poles[1][b]/poles[1][a]
k_ = 1/(poles[0][a]**(S(3)/2)*poles[1][a])/a_**2*constants
if a_.is_positive:
result = (
k_*(2/sqrt(pi)*a_*sqrt(t)+exp(a_**2*t)*erfc(a_*sqrt(t))-1))
_debug(' rule 5.3.8')
elif (
poles[0][n] == -2 and poles[0][m] == S.Half and
poles[1][n] == -1 and poles[1][m] == 1 and
poles[1][b] == 0):
# 1/((a0*sqrt(s)+b0)**2*a1*s)
# == 1/a0**2/a1 * 1/(sqrt(s)+b0/a0)**2/s
a_sq = poles[0][b]/poles[0][a]
a_ = a_sq**2
k_ = 1/poles[0][a]**2/poles[1][a]*constants
if a_sq.is_positive:
result = (
k_*(1/a_ + (2*t-1/a_)*exp(a_*t)*erfc(sqrt(a_)*sqrt(t)) -
2/sqrt(pi)/sqrt(a_)*sqrt(t)))
_debug(' rule 5.3.11')
elif (
poles[0][n] == -2 and poles[0][m] == S.Half and
poles[1][n] == -S.Half and poles[1][m] == 1 and
poles[1][b] == 0):
# 1/((a0*sqrt(s)+b0)**2*sqrt(a1*s))
# == 1/a0**2/sqrt(a1) * 1/(sqrt(s)+b0/a0)**2/sqrt(s)
a_ = poles[0][b]/poles[0][a]
k_ = 1/poles[0][a]**2/sqrt(poles[1][a])*constants
if a_.is_positive:
result = (
k_*(2/sqrt(pi)*sqrt(t) -
2*a_*t*exp(a_**2*t)*erfc(a_*sqrt(t))))
_debug(' rule 5.3.12')
elif (
poles[0][n] == -3 and poles[0][m] == S.Half and
poles[1][n] == -S.Half and poles[1][m] == 1 and
poles[1][b] == 0):
# 1 / (sqrt(a1*s)*(a0*sqrt(s+b0)**3))
# == 1/(sqrt(a1)*a0) * 1/(sqrt(s)*(sqrt(s+b0)**3))
a_ = poles[0][b]
k_ = constants/sqrt(poles[1][a])/poles[0][a]
result = k_*(
(2*a_**2*t+1)*t*exp(a_**2*t)*erfc(a_*sqrt(t)) -
2/sqrt(pi)*a_*t**(S(3)/2))
_debug(' rule 5.3.15')
elif (
poles[0][n] == -1 and poles[0][m] == 1 and
poles[1][n] == -S.Half and poles[1][m] == 1):
# 1 / ( (a0*s+b0)* sqrt(a1*s+b1) )
# == 1/(sqrt(a1)*a0) * 1 / ( (s+b0/a0)* sqrt(s+b1/a1) )
a_ = poles[0][b]/poles[0][a]
b_ = poles[1][b]/poles[1][a]
k_ = constants/sqrt(poles[1][a])/poles[0][a]
result = k_*(
1/sqrt(b_-a_)*exp(-a_*t)*erf(sqrt(b_-a_)*sqrt(t)))
_debug(' rule 5.3.23')
elif len(poles) == 2 and len(zeros) == 1:
if (
poles[0][n] == -1 and poles[0][m] == 1 and
poles[1][n] == -1 and poles[1][m] == S.Half and
zeros[0][n] == S.Half and zeros[0][m] == 1 and
zeros[0][b] == 0):
# sqrt(za0*s)/((a0*s+b0)*(a1*sqrt(s)+b1))
# == sqrt(za0)/(a0*a1) * s/((s+b0/a0)*(sqrt(s)+b1/a1))
a_sq = poles[1][b]/poles[1][a]
a_ = a_sq**2
b_ = -poles[0][b]/poles[0][a]
k_ = sqrt(zeros[0][a])/poles[0][a]/poles[1][a]/(a_-b_)*constants
if a_sq.is_positive and b_.is_positive:
result = k_*(
a_*exp(a_*t)*erfc(sqrt(a_)*sqrt(t)) +
sqrt(a_)*sqrt(b_)*exp(b_*t)*erfc(sqrt(b_)*sqrt(t)) -
b_*exp(b_*t))
_debug(' rule 5.3.6')
elif (
poles[0][n] == -1 and poles[0][m] == 1 and
poles[0][b] == 0 and poles[1][n] == -1 and
poles[1][m] == S.Half and zeros[0][n] == 1 and
zeros[0][m] == S.Half):
# (az*sqrt(s)+bz)/(a0*s*(a1*sqrt(s)+b1))
# == az/a0/a1 * (sqrt(z)+bz/az)/(s*(sqrt(s)+b1/a1))
a_num = zeros[0][b]/zeros[0][a]
a_ = poles[1][b]/poles[1][a]
if a_+a_num == 0:
k_ = zeros[0][a]/poles[0][a]/poles[1][a]*constants
result = k_*(
2*exp(a_**2*t)*erfc(a_*sqrt(t))-1)
_debug(' rule 5.3.17')
elif (
poles[1][n] == -1 and poles[1][m] == 1 and
poles[1][b] == 0 and poles[0][n] == -2 and
poles[0][m] == S.Half and zeros[0][n] == 2 and
zeros[0][m] == S.Half):
# (az*sqrt(s)+bz)**2/(a1*s*(a0*sqrt(s)+b0)**2)
# == az**2/a1/a0**2 * (sqrt(z)+bz/az)**2/(s*(sqrt(s)+b0/a0)**2)
a_num = zeros[0][b]/zeros[0][a]
a_ = poles[0][b]/poles[0][a]
if a_+a_num == 0:
k_ = zeros[0][a]**2/poles[1][a]/poles[0][a]**2*constants
result = k_*(
1 + 8*a_**2*t*exp(a_**2*t)*erfc(a_*sqrt(t)) -
8/sqrt(pi)*a_*sqrt(t))
_debug(' rule 5.3.18')
elif (
poles[1][n] == -1 and poles[1][m] == 1 and
poles[1][b] == 0 and poles[0][n] == -3 and
poles[0][m] == S.Half and zeros[0][n] == 3 and
zeros[0][m] == S.Half):
# (az*sqrt(s)+bz)**3/(a1*s*(a0*sqrt(s)+b0)**3)
# == az**3/a1/a0**3 * (sqrt(z)+bz/az)**3/(s*(sqrt(s)+b0/a0)**3)
a_num = zeros[0][b]/zeros[0][a]
a_ = poles[0][b]/poles[0][a]
if a_+a_num == 0:
k_ = zeros[0][a]**3/poles[1][a]/poles[0][a]**3*constants
result = k_*(
2*(8*a_**4*t**2+8*a_**2*t+1)*exp(a_**2*t) *
erfc(a_*sqrt(t))-8/sqrt(pi)*a_*sqrt(t)*(2*a_**2*t+1)-1)
_debug(' rule 5.3.19')
elif len(poles) == 3 and len(zeros) == 0:
if (
poles[0][n] == -1 and poles[0][b] == 0 and poles[0][m] == 1 and
poles[1][n] == -1 and poles[1][m] == 1 and
poles[2][n] == -S.Half and poles[2][m] == 1):
# 1/((a0*s)*(a1*s+b1)*sqrt(a2*s))
# == 1/(a0*a1*sqrt(a2)) * 1/((s)*(s+b1/a1)*sqrt(s))
a_ = -poles[1][b]/poles[1][a]
k_ = 1/poles[0][a]/poles[1][a]/sqrt(poles[2][a])*constants
if a_.is_positive:
result = k_ * (
a_**(-S(3)/2) * exp(a_*t) * erf(sqrt(a_)*sqrt(t)) -
2/a_/sqrt(pi)*sqrt(t))
_debug(' rule 5.3.2')
elif (
poles[0][n] == -1 and poles[0][m] == 1 and
poles[1][n] == -1 and poles[1][m] == S.Half and
poles[2][n] == -S.Half and poles[2][m] == 1 and
poles[2][b] == 0):
# 1/((a0*s+b0)*(a1*sqrt(s)+b1)*(sqrt(a2)*sqrt(s)))
# == 1/(a0*a1*sqrt(a2)) * 1/((s+b0/a0)*(sqrt(s)+b1/a1)*sqrt(s))
a_sq = poles[1][b]/poles[1][a]
a_ = a_sq**2
b_ = -poles[0][b]/poles[0][a]
k_ = (
1/poles[0][a]/poles[1][a]/sqrt(poles[2][a]) /
(sqrt(b_)*(a_-b_)))
if a_sq.is_positive and b_.is_positive:
result = k_ * (
sqrt(b_)*exp(a_*t)*erfc(sqrt(a_)*sqrt(t)) +
sqrt(a_)*exp(b_*t)*erf(sqrt(b_)*sqrt(t)) -
sqrt(b_)*exp(b_*t))
_debug(' rule 5.3.9')
if result is None:
return None
else:
return Heaviside(t)*result, condition
@DEBUG_WRAP
def _inverse_laplace_early_prog_rules(F, s, t, plane):
"""
Helper function for the class InverseLaplaceTransform.
"""
prog_rules = [_inverse_laplace_irrational]
for p_rule in prog_rules:
if (r := p_rule(F, s, t, plane)) is not None:
return r
return None
@DEBUG_WRAP
def _inverse_laplace_apply_prog_rules(F, s, t, plane):
"""
Helper function for the class InverseLaplaceTransform.
"""
prog_rules = [_inverse_laplace_time_shift, _inverse_laplace_freq_shift,
_inverse_laplace_time_diff, _inverse_laplace_diff,
_inverse_laplace_irrational]
for p_rule in prog_rules:
if (r := p_rule(F, s, t, plane)) is not None:
return r
return None
@DEBUG_WRAP
def _inverse_laplace_expand(fn, s, t, plane):
"""
Helper function for the class InverseLaplaceTransform.
"""
if fn.is_Add:
return None
r = expand(fn, deep=False)
if r.is_Add:
return _inverse_laplace_transform(
r, s, t, plane, simplify=False, dorational=True)
r = expand_mul(fn)
if r.is_Add:
return _inverse_laplace_transform(
r, s, t, plane, simplify=False, dorational=True)
r = expand(fn)
if r.is_Add:
return _inverse_laplace_transform(
r, s, t, plane, simplify=False, dorational=True)
if fn.is_rational_function(s):
r = fn.apart(s).doit()
if r.is_Add:
return _inverse_laplace_transform(
r, s, t, plane, simplify=False, dorational=True)
return None
@DEBUG_WRAP
def _inverse_laplace_rational(fn, s, t, plane, *, simplify):
"""
Helper function for the class InverseLaplaceTransform.
"""
x_ = symbols('x_')
f = fn.apart(s)
terms = Add.make_args(f)
terms_t = []
conditions = [S.true]
for term in terms:
[n, d] = term.as_numer_denom()
dc = d.as_poly(s).all_coeffs()
dc_lead = dc[0]
dc = [x/dc_lead for x in dc]
nc = [x/dc_lead for x in n.as_poly(s).all_coeffs()]
if len(dc) == 1:
r = nc[0]*DiracDelta(t)
terms_t.append(r)
elif len(dc) == 2:
r = nc[0]*exp(-dc[1]*t)
terms_t.append(Heaviside(t)*r)
elif len(dc) == 3:
a = dc[1]/2
b = (dc[2]-a**2).factor()
if len(nc) == 1:
nc = [S.Zero] + nc
l, m = tuple(nc)
if b == 0:
r = (m*t+l*(1-a*t))*exp(-a*t)
else:
hyp = False
if b.is_negative:
b = -b
hyp = True
b2 = list(roots(x_**2-b, x_).keys())[0]
bs = sqrt(b).simplify()
if hyp:
r = (
l*exp(-a*t)*cosh(b2*t) + (m-a*l) /
bs*exp(-a*t)*sinh(bs*t))
else:
r = l*exp(-a*t)*cos(b2*t) + (m-a*l)/bs*exp(-a*t)*sin(bs*t)
terms_t.append(Heaviside(t)*r)
else:
ft, cond = _inverse_laplace_transform(
term, s, t, plane, simplify=simplify, dorational=False)
terms_t.append(ft)
conditions.append(cond)
result = Add(*terms_t)
if simplify:
result = result.simplify(doit=False)
return result, And(*conditions)
@DEBUG_WRAP
def _inverse_laplace_transform(fn, s_, t_, plane, *, simplify, dorational):
"""
Front-end function of the inverse Laplace transform. It tries to apply all
known rules recursively. If everything else fails, it tries to integrate.
"""
terms = Add.make_args(fn)
terms_t = []
conditions = []
for term in terms:
if term.has(exp):
# Simplify expressions with exp() such that time-shifted
# expressions have negative exponents in the numerator instead of
# positive exponents in the numerator and denominator; this is a
# (necessary) trick. It will, for example, convert
# (s**2*exp(2*s) + 4*exp(s) - 4)*exp(-2*s)/(s*(s**2 + 1)) into
# (s**2 + 4*exp(-s) - 4*exp(-2*s))/(s*(s**2 + 1))
term = term.subs(s_, -s_).together().subs(s_, -s_)
k, f = term.as_independent(s_, as_Add=False)
if (
dorational and term.is_rational_function(s_) and
(r := _inverse_laplace_rational(
f, s_, t_, plane, simplify=simplify))
is not None or
(r := _inverse_laplace_apply_simple_rules(f, s_, t_))
is not None or
(r := _inverse_laplace_early_prog_rules(f, s_, t_, plane))
is not None or
(r := _inverse_laplace_expand(f, s_, t_, plane))
is not None or
(r := _inverse_laplace_apply_prog_rules(f, s_, t_, plane))
is not None):
pass
elif any(undef.has(s_) for undef in f.atoms(AppliedUndef)):
# If there are undefined functions f(t) then integration is
# unlikely to do anything useful so we skip it and given an
# unevaluated LaplaceTransform.
r = (InverseLaplaceTransform(f, s_, t_, plane), S.true)
elif (
r := _inverse_laplace_transform_integration(
f, s_, t_, plane, simplify=simplify)) is not None:
pass
else:
r = (InverseLaplaceTransform(f, s_, t_, plane), S.true)
(ri_, ci_) = r
terms_t.append(k*ri_)
conditions.append(ci_)
result = Add(*terms_t)
if simplify:
result = result.simplify(doit=False)
condition = And(*conditions)
return result, condition
class InverseLaplaceTransform(IntegralTransform):
"""
Class representing unevaluated inverse Laplace transforms.
For usage of this class, see the :class:`IntegralTransform` docstring.
For how to compute inverse Laplace transforms, see the
:func:`inverse_laplace_transform` docstring.
"""
_name = 'Inverse Laplace'
_none_sentinel = Dummy('None')
_c = Dummy('c')
def __new__(cls, F, s, x, plane, **opts):
if plane is None:
plane = InverseLaplaceTransform._none_sentinel
return IntegralTransform.__new__(cls, F, s, x, plane, **opts)
@property
def fundamental_plane(self):
plane = self.args[3]
if plane is InverseLaplaceTransform._none_sentinel:
plane = None
return plane
def _compute_transform(self, F, s, t, **hints):
return _inverse_laplace_transform_integration(
F, s, t, self.fundamental_plane, **hints)
def _as_integral(self, F, s, t):
c = self.__class__._c
return (
Integral(exp(s*t)*F, (s, c - S.ImaginaryUnit*S.Infinity,
c + S.ImaginaryUnit*S.Infinity)) /
(2*S.Pi*S.ImaginaryUnit))
def doit(self, **hints):
"""
Try to evaluate the transform in closed form.
Explanation
===========
Standard hints are the following:
- ``noconds``: if True, do not return convergence conditions. The
default setting is `True`.
- ``simplify``: if True, it simplifies the final result. The
default setting is `False`.
"""
_noconds = hints.get('noconds', True)
_simplify = hints.get('simplify', False)
debugf('[ILT doit] (%s, %s, %s)', (self.function,
self.function_variable,
self.transform_variable))
s_ = self.function_variable
t_ = self.transform_variable
fn = self.function
plane = self.fundamental_plane
r = _inverse_laplace_transform(
fn, s_, t_, plane, simplify=_simplify, dorational=True)
if _noconds:
return r[0]
else:
return r
def inverse_laplace_transform(F, s, t, plane=None, **hints):
r"""
Compute the inverse Laplace transform of `F(s)`, defined as
.. math ::
f(t) = \frac{1}{2\pi i} \int_{c-i\infty}^{c+i\infty} e^{st}
F(s) \mathrm{d}s,
for `c` so large that `F(s)` has no singularites in the
half-plane `\operatorname{Re}(s) > c-\epsilon`.
Explanation
===========
The plane can be specified by
argument ``plane``, but will be inferred if passed as None.
Under certain regularity conditions, this recovers `f(t)` from its
Laplace Transform `F(s)`, for non-negative `t`, and vice
versa.
If the integral cannot be computed in closed form, this function returns
an unevaluated :class:`InverseLaplaceTransform` object.
Note that this function will always assume `t` to be real,
regardless of the SymPy assumption on `t`.
For a description of possible hints, refer to the docstring of
:func:`sympy.integrals.transforms.IntegralTransform.doit`.
Examples
========
>>> from sympy import inverse_laplace_transform, exp, Symbol
>>> from sympy.abc import s, t
>>> a = Symbol('a', positive=True)
>>> inverse_laplace_transform(exp(-a*s)/s, s, t)
Heaviside(-a + t)
See Also
========
laplace_transform
hankel_transform, inverse_hankel_transform
"""
_noconds = hints.get('noconds', True)
_simplify = hints.get('simplify', False)
if isinstance(F, MatrixBase) and hasattr(F, 'applyfunc'):
return F.applyfunc(
lambda Fij: inverse_laplace_transform(Fij, s, t, plane, **hints))
r, c = InverseLaplaceTransform(F, s, t, plane).doit(
noconds=False, simplify=_simplify)
if _noconds:
return r
else:
return r, c
def _fast_inverse_laplace(e, s, t):
"""Fast inverse Laplace transform of rational function including RootSum"""
a, b, n = symbols('a, b, n', cls=Wild, exclude=[s])
def _ilt(e):
if not e.has(s):
return e
elif e.is_Add:
return _ilt_add(e)
elif e.is_Mul:
return _ilt_mul(e)
elif e.is_Pow:
return _ilt_pow(e)
elif isinstance(e, RootSum):
return _ilt_rootsum(e)
else:
raise NotImplementedError
def _ilt_add(e):
return e.func(*map(_ilt, e.args))
def _ilt_mul(e):
coeff, expr = e.as_independent(s)
if expr.is_Mul:
raise NotImplementedError
return coeff * _ilt(expr)
def _ilt_pow(e):
match = e.match((a*s + b)**n)
if match is not None:
nm, am, bm = match[n], match[a], match[b]
if nm.is_Integer and nm < 0:
return t**(-nm-1)*exp(-(bm/am)*t)/(am**-nm*gamma(-nm))
if nm == 1:
return exp(-(bm/am)*t) / am
raise NotImplementedError
def _ilt_rootsum(e):
expr = e.fun.expr
[variable] = e.fun.variables
return RootSum(e.poly, Lambda(variable, together(_ilt(expr))))
return _ilt(e)
PK ]ZZZ���И' �' " sympy/integrals/manualintegrate.py"""Integration method that emulates by-hand techniques.
This module also provides functionality to get the steps used to evaluate a
particular integral, in the ``integral_steps`` function. This will return
nested ``Rule`` s representing the integration rules used.
Each ``Rule`` class represents a (maybe parametrized) integration rule, e.g.
``SinRule`` for integrating ``sin(x)`` and ``ReciprocalSqrtQuadraticRule``
for integrating ``1/sqrt(a+b*x+c*x**2)``. The ``eval`` method returns the
integration result.
The ``manualintegrate`` function computes the integral by calling ``eval``
on the rule returned by ``integral_steps``.
The integrator can be extended with new heuristics and evaluation
techniques. To do so, extend the ``Rule`` class, implement ``eval`` method,
then write a function that accepts an ``IntegralInfo`` object and returns
either a ``Rule`` instance or ``None``. If the new technique requires a new
match, add the key and call to the antiderivative function to integral_steps.
To enable simple substitutions, add the match to find_substitutions.
"""
from __future__ import annotations
from typing import NamedTuple, Type, Callable, Sequence
from abc import ABC, abstractmethod
from dataclasses import dataclass
from collections import defaultdict
from collections.abc import Mapping
from sympy.core.add import Add
from sympy.core.cache import cacheit
from sympy.core.containers import Dict
from sympy.core.expr import Expr
from sympy.core.function import Derivative
from sympy.core.logic import fuzzy_not
from sympy.core.mul import Mul
from sympy.core.numbers import Integer, Number, E
from sympy.core.power import Pow
from sympy.core.relational import Eq, Ne, Boolean
from sympy.core.singleton import S
from sympy.core.symbol import Dummy, Symbol, Wild
from sympy.functions.elementary.complexes import Abs
from sympy.functions.elementary.exponential import exp, log
from sympy.functions.elementary.hyperbolic import (HyperbolicFunction, csch,
cosh, coth, sech, sinh, tanh, asinh)
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.elementary.piecewise import Piecewise
from sympy.functions.elementary.trigonometric import (TrigonometricFunction,
cos, sin, tan, cot, csc, sec, acos, asin, atan, acot, acsc, asec)
from sympy.functions.special.delta_functions import Heaviside, DiracDelta
from sympy.functions.special.error_functions import (erf, erfi, fresnelc,
fresnels, Ci, Chi, Si, Shi, Ei, li)
from sympy.functions.special.gamma_functions import uppergamma
from sympy.functions.special.elliptic_integrals import elliptic_e, elliptic_f
from sympy.functions.special.polynomials import (chebyshevt, chebyshevu,
legendre, hermite, laguerre, assoc_laguerre, gegenbauer, jacobi,
OrthogonalPolynomial)
from sympy.functions.special.zeta_functions import polylog
from .integrals import Integral
from sympy.logic.boolalg import And
from sympy.ntheory.factor_ import primefactors
from sympy.polys.polytools import degree, lcm_list, gcd_list, Poly
from sympy.simplify.radsimp import fraction
from sympy.simplify.simplify import simplify
from sympy.solvers.solvers import solve
from sympy.strategies.core import switch, do_one, null_safe, condition
from sympy.utilities.iterables import iterable
from sympy.utilities.misc import debug
@dataclass
class Rule(ABC):
integrand: Expr
variable: Symbol
@abstractmethod
def eval(self) -> Expr:
pass
@abstractmethod
def contains_dont_know(self) -> bool:
pass
@dataclass
class AtomicRule(Rule, ABC):
"""A simple rule that does not depend on other rules"""
def contains_dont_know(self) -> bool:
return False
@dataclass
class ConstantRule(AtomicRule):
"""integrate(a, x) -> a*x"""
def eval(self) -> Expr:
return self.integrand * self.variable
@dataclass
class ConstantTimesRule(Rule):
"""integrate(a*f(x), x) -> a*integrate(f(x), x)"""
constant: Expr
other: Expr
substep: Rule
def eval(self) -> Expr:
return self.constant * self.substep.eval()
def contains_dont_know(self) -> bool:
return self.substep.contains_dont_know()
@dataclass
class PowerRule(AtomicRule):
"""integrate(x**a, x)"""
base: Expr
exp: Expr
def eval(self) -> Expr:
return Piecewise(
((self.base**(self.exp + 1))/(self.exp + 1), Ne(self.exp, -1)),
(log(self.base), True),
)
@dataclass
class NestedPowRule(AtomicRule):
"""integrate((x**a)**b, x)"""
base: Expr
exp: Expr
def eval(self) -> Expr:
m = self.base * self.integrand
return Piecewise((m / (self.exp + 1), Ne(self.exp, -1)),
(m * log(self.base), True))
@dataclass
class AddRule(Rule):
"""integrate(f(x) + g(x), x) -> integrate(f(x), x) + integrate(g(x), x)"""
substeps: list[Rule]
def eval(self) -> Expr:
return Add(*(substep.eval() for substep in self.substeps))
def contains_dont_know(self) -> bool:
return any(substep.contains_dont_know() for substep in self.substeps)
@dataclass
class URule(Rule):
"""integrate(f(g(x))*g'(x), x) -> integrate(f(u), u), u = g(x)"""
u_var: Symbol
u_func: Expr
substep: Rule
def eval(self) -> Expr:
result = self.substep.eval()
if self.u_func.is_Pow:
base, exp_ = self.u_func.as_base_exp()
if exp_ == -1:
# avoid needless -log(1/x) from substitution
result = result.subs(log(self.u_var), -log(base))
return result.subs(self.u_var, self.u_func)
def contains_dont_know(self) -> bool:
return self.substep.contains_dont_know()
@dataclass
class PartsRule(Rule):
"""integrate(u(x)*v'(x), x) -> u(x)*v(x) - integrate(u'(x)*v(x), x)"""
u: Symbol
dv: Expr
v_step: Rule
second_step: Rule | None # None when is a substep of CyclicPartsRule
def eval(self) -> Expr:
assert self.second_step is not None
v = self.v_step.eval()
return self.u * v - self.second_step.eval()
def contains_dont_know(self) -> bool:
return self.v_step.contains_dont_know() or (
self.second_step is not None and self.second_step.contains_dont_know())
@dataclass
class CyclicPartsRule(Rule):
"""Apply PartsRule multiple times to integrate exp(x)*sin(x)"""
parts_rules: list[PartsRule]
coefficient: Expr
def eval(self) -> Expr:
result = []
sign = 1
for rule in self.parts_rules:
result.append(sign * rule.u * rule.v_step.eval())
sign *= -1
return Add(*result) / (1 - self.coefficient)
def contains_dont_know(self) -> bool:
return any(substep.contains_dont_know() for substep in self.parts_rules)
@dataclass
class TrigRule(AtomicRule, ABC):
pass
@dataclass
class SinRule(TrigRule):
"""integrate(sin(x), x) -> -cos(x)"""
def eval(self) -> Expr:
return -cos(self.variable)
@dataclass
class CosRule(TrigRule):
"""integrate(cos(x), x) -> sin(x)"""
def eval(self) -> Expr:
return sin(self.variable)
@dataclass
class SecTanRule(TrigRule):
"""integrate(sec(x)*tan(x), x) -> sec(x)"""
def eval(self) -> Expr:
return sec(self.variable)
@dataclass
class CscCotRule(TrigRule):
"""integrate(csc(x)*cot(x), x) -> -csc(x)"""
def eval(self) -> Expr:
return -csc(self.variable)
@dataclass
class Sec2Rule(TrigRule):
"""integrate(sec(x)**2, x) -> tan(x)"""
def eval(self) -> Expr:
return tan(self.variable)
@dataclass
class Csc2Rule(TrigRule):
"""integrate(csc(x)**2, x) -> -cot(x)"""
def eval(self) -> Expr:
return -cot(self.variable)
@dataclass
class HyperbolicRule(AtomicRule, ABC):
pass
@dataclass
class SinhRule(HyperbolicRule):
"""integrate(sinh(x), x) -> cosh(x)"""
def eval(self) -> Expr:
return cosh(self.variable)
@dataclass
class CoshRule(HyperbolicRule):
"""integrate(cosh(x), x) -> sinh(x)"""
def eval(self):
return sinh(self.variable)
@dataclass
class ExpRule(AtomicRule):
"""integrate(a**x, x) -> a**x/ln(a)"""
base: Expr
exp: Expr
def eval(self) -> Expr:
return self.integrand / log(self.base)
@dataclass
class ReciprocalRule(AtomicRule):
"""integrate(1/x, x) -> ln(x)"""
base: Expr
def eval(self) -> Expr:
return log(self.base)
@dataclass
class ArcsinRule(AtomicRule):
"""integrate(1/sqrt(1-x**2), x) -> asin(x)"""
def eval(self) -> Expr:
return asin(self.variable)
@dataclass
class ArcsinhRule(AtomicRule):
"""integrate(1/sqrt(1+x**2), x) -> asin(x)"""
def eval(self) -> Expr:
return asinh(self.variable)
@dataclass
class ReciprocalSqrtQuadraticRule(AtomicRule):
"""integrate(1/sqrt(a+b*x+c*x**2), x) -> log(2*sqrt(c)*sqrt(a+b*x+c*x**2)+b+2*c*x)/sqrt(c)"""
a: Expr
b: Expr
c: Expr
def eval(self) -> Expr:
a, b, c, x = self.a, self.b, self.c, self.variable
return log(2*sqrt(c)*sqrt(a+b*x+c*x**2)+b+2*c*x)/sqrt(c)
@dataclass
class SqrtQuadraticDenomRule(AtomicRule):
"""integrate(poly(x)/sqrt(a+b*x+c*x**2), x)"""
a: Expr
b: Expr
c: Expr
coeffs: list[Expr]
def eval(self) -> Expr:
a, b, c, coeffs, x = self.a, self.b, self.c, self.coeffs.copy(), self.variable
# Integrate poly/sqrt(a+b*x+c*x**2) using recursion.
# coeffs are coefficients of the polynomial.
# Let I_n = x**n/sqrt(a+b*x+c*x**2), then
# I_n = A * x**(n-1)*sqrt(a+b*x+c*x**2) - B * I_{n-1} - C * I_{n-2}
# where A = 1/(n*c), B = (2*n-1)*b/(2*n*c), C = (n-1)*a/(n*c)
# See https://github.com/sympy/sympy/pull/23608 for proof.
result_coeffs = []
coeffs = coeffs.copy()
for i in range(len(coeffs)-2):
n = len(coeffs)-1-i
coeff = coeffs[i]/(c*n)
result_coeffs.append(coeff)
coeffs[i+1] -= (2*n-1)*b/2*coeff
coeffs[i+2] -= (n-1)*a*coeff
d, e = coeffs[-1], coeffs[-2]
s = sqrt(a+b*x+c*x**2)
constant = d-b*e/(2*c)
if constant == 0:
I0 = 0
else:
step = inverse_trig_rule(IntegralInfo(1/s, x), degenerate=False)
I0 = constant*step.eval()
return Add(*(result_coeffs[i]*x**(len(coeffs)-2-i)
for i in range(len(result_coeffs))), e/c)*s + I0
@dataclass
class SqrtQuadraticRule(AtomicRule):
"""integrate(sqrt(a+b*x+c*x**2), x)"""
a: Expr
b: Expr
c: Expr
def eval(self) -> Expr:
step = sqrt_quadratic_rule(IntegralInfo(self.integrand, self.variable), degenerate=False)
return step.eval()
@dataclass
class AlternativeRule(Rule):
"""Multiple ways to do integration."""
alternatives: list[Rule]
def eval(self) -> Expr:
return self.alternatives[0].eval()
def contains_dont_know(self) -> bool:
return any(substep.contains_dont_know() for substep in self.alternatives)
@dataclass
class DontKnowRule(Rule):
"""Leave the integral as is."""
def eval(self) -> Expr:
return Integral(self.integrand, self.variable)
def contains_dont_know(self) -> bool:
return True
@dataclass
class DerivativeRule(AtomicRule):
"""integrate(f'(x), x) -> f(x)"""
def eval(self) -> Expr:
assert isinstance(self.integrand, Derivative)
variable_count = list(self.integrand.variable_count)
for i, (var, count) in enumerate(variable_count):
if var == self.variable:
variable_count[i] = (var, count - 1)
break
return Derivative(self.integrand.expr, *variable_count)
@dataclass
class RewriteRule(Rule):
"""Rewrite integrand to another form that is easier to handle."""
rewritten: Expr
substep: Rule
def eval(self) -> Expr:
return self.substep.eval()
def contains_dont_know(self) -> bool:
return self.substep.contains_dont_know()
@dataclass
class CompleteSquareRule(RewriteRule):
"""Rewrite a+b*x+c*x**2 to a-b**2/(4*c) + c*(x+b/(2*c))**2"""
pass
@dataclass
class PiecewiseRule(Rule):
subfunctions: Sequence[tuple[Rule, bool | Boolean]]
def eval(self) -> Expr:
return Piecewise(*[(substep.eval(), cond)
for substep, cond in self.subfunctions])
def contains_dont_know(self) -> bool:
return any(substep.contains_dont_know() for substep, _ in self.subfunctions)
@dataclass
class HeavisideRule(Rule):
harg: Expr
ibnd: Expr
substep: Rule
def eval(self) -> Expr:
# If we are integrating over x and the integrand has the form
# Heaviside(m*x+b)*g(x) == Heaviside(harg)*g(symbol)
# then there needs to be continuity at -b/m == ibnd,
# so we subtract the appropriate term.
result = self.substep.eval()
return Heaviside(self.harg) * (result - result.subs(self.variable, self.ibnd))
def contains_dont_know(self) -> bool:
return self.substep.contains_dont_know()
@dataclass
class DiracDeltaRule(AtomicRule):
n: Expr
a: Expr
b: Expr
def eval(self) -> Expr:
n, a, b, x = self.n, self.a, self.b, self.variable
if n == 0:
return Heaviside(a+b*x)/b
return DiracDelta(a+b*x, n-1)/b
@dataclass
class TrigSubstitutionRule(Rule):
theta: Expr
func: Expr
rewritten: Expr
substep: Rule
restriction: bool | Boolean
def eval(self) -> Expr:
theta, func, x = self.theta, self.func, self.variable
func = func.subs(sec(theta), 1/cos(theta))
func = func.subs(csc(theta), 1/sin(theta))
func = func.subs(cot(theta), 1/tan(theta))
trig_function = list(func.find(TrigonometricFunction))
assert len(trig_function) == 1
trig_function = trig_function[0]
relation = solve(x - func, trig_function)
assert len(relation) == 1
numer, denom = fraction(relation[0])
if isinstance(trig_function, sin):
opposite = numer
hypotenuse = denom
adjacent = sqrt(denom**2 - numer**2)
inverse = asin(relation[0])
elif isinstance(trig_function, cos):
adjacent = numer
hypotenuse = denom
opposite = sqrt(denom**2 - numer**2)
inverse = acos(relation[0])
else: # tan
opposite = numer
adjacent = denom
hypotenuse = sqrt(denom**2 + numer**2)
inverse = atan(relation[0])
substitution = [
(sin(theta), opposite/hypotenuse),
(cos(theta), adjacent/hypotenuse),
(tan(theta), opposite/adjacent),
(theta, inverse)
]
return Piecewise(
(self.substep.eval().subs(substitution).trigsimp(), self.restriction)
)
def contains_dont_know(self) -> bool:
return self.substep.contains_dont_know()
@dataclass
class ArctanRule(AtomicRule):
"""integrate(a/(b*x**2+c), x) -> a/b / sqrt(c/b) * atan(x/sqrt(c/b))"""
a: Expr
b: Expr
c: Expr
def eval(self) -> Expr:
a, b, c, x = self.a, self.b, self.c, self.variable
return a/b / sqrt(c/b) * atan(x/sqrt(c/b))
@dataclass
class OrthogonalPolyRule(AtomicRule, ABC):
n: Expr
@dataclass
class JacobiRule(OrthogonalPolyRule):
a: Expr
b: Expr
def eval(self) -> Expr:
n, a, b, x = self.n, self.a, self.b, self.variable
return Piecewise(
(2*jacobi(n + 1, a - 1, b - 1, x)/(n + a + b), Ne(n + a + b, 0)),
(x, Eq(n, 0)),
((a + b + 2)*x**2/4 + (a - b)*x/2, Eq(n, 1)))
@dataclass
class GegenbauerRule(OrthogonalPolyRule):
a: Expr
def eval(self) -> Expr:
n, a, x = self.n, self.a, self.variable
return Piecewise(
(gegenbauer(n + 1, a - 1, x)/(2*(a - 1)), Ne(a, 1)),
(chebyshevt(n + 1, x)/(n + 1), Ne(n, -1)),
(S.Zero, True))
@dataclass
class ChebyshevTRule(OrthogonalPolyRule):
def eval(self) -> Expr:
n, x = self.n, self.variable
return Piecewise(
((chebyshevt(n + 1, x)/(n + 1) -
chebyshevt(n - 1, x)/(n - 1))/2, Ne(Abs(n), 1)),
(x**2/2, True))
@dataclass
class ChebyshevURule(OrthogonalPolyRule):
def eval(self) -> Expr:
n, x = self.n, self.variable
return Piecewise(
(chebyshevt(n + 1, x)/(n + 1), Ne(n, -1)),
(S.Zero, True))
@dataclass
class LegendreRule(OrthogonalPolyRule):
def eval(self) -> Expr:
n, x = self.n, self.variable
return(legendre(n + 1, x) - legendre(n - 1, x))/(2*n + 1)
@dataclass
class HermiteRule(OrthogonalPolyRule):
def eval(self) -> Expr:
n, x = self.n, self.variable
return hermite(n + 1, x)/(2*(n + 1))
@dataclass
class LaguerreRule(OrthogonalPolyRule):
def eval(self) -> Expr:
n, x = self.n, self.variable
return laguerre(n, x) - laguerre(n + 1, x)
@dataclass
class AssocLaguerreRule(OrthogonalPolyRule):
a: Expr
def eval(self) -> Expr:
return -assoc_laguerre(self.n + 1, self.a - 1, self.variable)
@dataclass
class IRule(AtomicRule, ABC):
a: Expr
b: Expr
@dataclass
class CiRule(IRule):
def eval(self) -> Expr:
a, b, x = self.a, self.b, self.variable
return cos(b)*Ci(a*x) - sin(b)*Si(a*x)
@dataclass
class ChiRule(IRule):
def eval(self) -> Expr:
a, b, x = self.a, self.b, self.variable
return cosh(b)*Chi(a*x) + sinh(b)*Shi(a*x)
@dataclass
class EiRule(IRule):
def eval(self) -> Expr:
a, b, x = self.a, self.b, self.variable
return exp(b)*Ei(a*x)
@dataclass
class SiRule(IRule):
def eval(self) -> Expr:
a, b, x = self.a, self.b, self.variable
return sin(b)*Ci(a*x) + cos(b)*Si(a*x)
@dataclass
class ShiRule(IRule):
def eval(self) -> Expr:
a, b, x = self.a, self.b, self.variable
return sinh(b)*Chi(a*x) + cosh(b)*Shi(a*x)
@dataclass
class LiRule(IRule):
def eval(self) -> Expr:
a, b, x = self.a, self.b, self.variable
return li(a*x + b)/a
@dataclass
class ErfRule(AtomicRule):
a: Expr
b: Expr
c: Expr
def eval(self) -> Expr:
a, b, c, x = self.a, self.b, self.c, self.variable
if a.is_extended_real:
return Piecewise(
(sqrt(S.Pi)/sqrt(-a)/2 * exp(c - b**2/(4*a)) *
erf((-2*a*x - b)/(2*sqrt(-a))), a < 0),
(sqrt(S.Pi)/sqrt(a)/2 * exp(c - b**2/(4*a)) *
erfi((2*a*x + b)/(2*sqrt(a))), True))
return sqrt(S.Pi)/sqrt(a)/2 * exp(c - b**2/(4*a)) * \
erfi((2*a*x + b)/(2*sqrt(a)))
@dataclass
class FresnelCRule(AtomicRule):
a: Expr
b: Expr
c: Expr
def eval(self) -> Expr:
a, b, c, x = self.a, self.b, self.c, self.variable
return sqrt(S.Pi)/sqrt(2*a) * (
cos(b**2/(4*a) - c)*fresnelc((2*a*x + b)/sqrt(2*a*S.Pi)) +
sin(b**2/(4*a) - c)*fresnels((2*a*x + b)/sqrt(2*a*S.Pi)))
@dataclass
class FresnelSRule(AtomicRule):
a: Expr
b: Expr
c: Expr
def eval(self) -> Expr:
a, b, c, x = self.a, self.b, self.c, self.variable
return sqrt(S.Pi)/sqrt(2*a) * (
cos(b**2/(4*a) - c)*fresnels((2*a*x + b)/sqrt(2*a*S.Pi)) -
sin(b**2/(4*a) - c)*fresnelc((2*a*x + b)/sqrt(2*a*S.Pi)))
@dataclass
class PolylogRule(AtomicRule):
a: Expr
b: Expr
def eval(self) -> Expr:
return polylog(self.b + 1, self.a * self.variable)
@dataclass
class UpperGammaRule(AtomicRule):
a: Expr
e: Expr
def eval(self) -> Expr:
a, e, x = self.a, self.e, self.variable
return x**e * (-a*x)**(-e) * uppergamma(e + 1, -a*x)/a
@dataclass
class EllipticFRule(AtomicRule):
a: Expr
d: Expr
def eval(self) -> Expr:
return elliptic_f(self.variable, self.d/self.a)/sqrt(self.a)
@dataclass
class EllipticERule(AtomicRule):
a: Expr
d: Expr
def eval(self) -> Expr:
return elliptic_e(self.variable, self.d/self.a)*sqrt(self.a)
class IntegralInfo(NamedTuple):
integrand: Expr
symbol: Symbol
def manual_diff(f, symbol):
"""Derivative of f in form expected by find_substitutions
SymPy's derivatives for some trig functions (like cot) are not in a form
that works well with finding substitutions; this replaces the
derivatives for those particular forms with something that works better.
"""
if f.args:
arg = f.args[0]
if isinstance(f, tan):
return arg.diff(symbol) * sec(arg)**2
elif isinstance(f, cot):
return -arg.diff(symbol) * csc(arg)**2
elif isinstance(f, sec):
return arg.diff(symbol) * sec(arg) * tan(arg)
elif isinstance(f, csc):
return -arg.diff(symbol) * csc(arg) * cot(arg)
elif isinstance(f, Add):
return sum(manual_diff(arg, symbol) for arg in f.args)
elif isinstance(f, Mul):
if len(f.args) == 2 and isinstance(f.args[0], Number):
return f.args[0] * manual_diff(f.args[1], symbol)
return f.diff(symbol)
def manual_subs(expr, *args):
"""
A wrapper for `expr.subs(*args)` with additional logic for substitution
of invertible functions.
"""
if len(args) == 1:
sequence = args[0]
if isinstance(sequence, (Dict, Mapping)):
sequence = sequence.items()
elif not iterable(sequence):
raise ValueError("Expected an iterable of (old, new) pairs")
elif len(args) == 2:
sequence = [args]
else:
raise ValueError("subs accepts either 1 or 2 arguments")
new_subs = []
for old, new in sequence:
if isinstance(old, log):
# If log(x) = y, then exp(a*log(x)) = exp(a*y)
# that is, x**a = exp(a*y). Replace nontrivial powers of x
# before subs turns them into `exp(y)**a`, but
# do not replace x itself yet, to avoid `log(exp(y))`.
x0 = old.args[0]
expr = expr.replace(lambda x: x.is_Pow and x.base == x0,
lambda x: exp(x.exp*new))
new_subs.append((x0, exp(new)))
return expr.subs(list(sequence) + new_subs)
# Method based on that on SIN, described in "Symbolic Integration: The
# Stormy Decade"
inverse_trig_functions = (atan, asin, acos, acot, acsc, asec)
def find_substitutions(integrand, symbol, u_var):
results = []
def test_subterm(u, u_diff):
if u_diff == 0:
return False
substituted = integrand / u_diff
debug("substituted: {}, u: {}, u_var: {}".format(substituted, u, u_var))
substituted = manual_subs(substituted, u, u_var).cancel()
if substituted.has_free(symbol):
return False
# avoid increasing the degree of a rational function
if integrand.is_rational_function(symbol) and substituted.is_rational_function(u_var):
deg_before = max(degree(t, symbol) for t in integrand.as_numer_denom())
deg_after = max(degree(t, u_var) for t in substituted.as_numer_denom())
if deg_after > deg_before:
return False
return substituted.as_independent(u_var, as_Add=False)
def exp_subterms(term: Expr):
linear_coeffs = []
terms = []
n = Wild('n', properties=[lambda n: n.is_Integer])
for exp_ in term.find(exp):
arg = exp_.args[0]
if symbol not in arg.free_symbols:
continue
match = arg.match(n*symbol)
if match:
linear_coeffs.append(match[n])
else:
terms.append(exp_)
if linear_coeffs:
terms.append(exp(gcd_list(linear_coeffs)*symbol))
return terms
def possible_subterms(term):
if isinstance(term, (TrigonometricFunction, HyperbolicFunction,
*inverse_trig_functions,
exp, log, Heaviside)):
return [term.args[0]]
elif isinstance(term, (chebyshevt, chebyshevu,
legendre, hermite, laguerre)):
return [term.args[1]]
elif isinstance(term, (gegenbauer, assoc_laguerre)):
return [term.args[2]]
elif isinstance(term, jacobi):
return [term.args[3]]
elif isinstance(term, Mul):
r = []
for u in term.args:
r.append(u)
r.extend(possible_subterms(u))
return r
elif isinstance(term, Pow):
r = [arg for arg in term.args if arg.has(symbol)]
if term.exp.is_Integer:
r.extend([term.base**d for d in primefactors(term.exp)
if 1 < d < abs(term.args[1])])
if term.base.is_Add:
r.extend([t for t in possible_subterms(term.base)
if t.is_Pow])
return r
elif isinstance(term, Add):
r = []
for arg in term.args:
r.append(arg)
r.extend(possible_subterms(arg))
return r
return []
for u in list(dict.fromkeys(possible_subterms(integrand) + exp_subterms(integrand))):
if u == symbol:
continue
u_diff = manual_diff(u, symbol)
new_integrand = test_subterm(u, u_diff)
if new_integrand is not False:
constant, new_integrand = new_integrand
if new_integrand == integrand.subs(symbol, u_var):
continue
substitution = (u, constant, new_integrand)
if substitution not in results:
results.append(substitution)
return results
def rewriter(condition, rewrite):
"""Strategy that rewrites an integrand."""
def _rewriter(integral):
integrand, symbol = integral
debug("Integral: {} is rewritten with {} on symbol: {}".format(integrand, rewrite, symbol))
if condition(*integral):
rewritten = rewrite(*integral)
if rewritten != integrand:
substep = integral_steps(rewritten, symbol)
if not isinstance(substep, DontKnowRule) and substep:
return RewriteRule(integrand, symbol, rewritten, substep)
return _rewriter
def proxy_rewriter(condition, rewrite):
"""Strategy that rewrites an integrand based on some other criteria."""
def _proxy_rewriter(criteria):
criteria, integral = criteria
integrand, symbol = integral
debug("Integral: {} is rewritten with {} on symbol: {} and criteria: {}".format(integrand, rewrite, symbol, criteria))
args = criteria + list(integral)
if condition(*args):
rewritten = rewrite(*args)
if rewritten != integrand:
return RewriteRule(integrand, symbol, rewritten, integral_steps(rewritten, symbol))
return _proxy_rewriter
def multiplexer(conditions):
"""Apply the rule that matches the condition, else None"""
def multiplexer_rl(expr):
for key, rule in conditions.items():
if key(expr):
return rule(expr)
return multiplexer_rl
def alternatives(*rules):
"""Strategy that makes an AlternativeRule out of multiple possible results."""
def _alternatives(integral):
alts = []
count = 0
debug("List of Alternative Rules")
for rule in rules:
count = count + 1
debug("Rule {}: {}".format(count, rule))
result = rule(integral)
if (result and not isinstance(result, DontKnowRule) and
result != integral and result not in alts):
alts.append(result)
if len(alts) == 1:
return alts[0]
elif alts:
doable = [rule for rule in alts if not rule.contains_dont_know()]
if doable:
return AlternativeRule(*integral, doable)
else:
return AlternativeRule(*integral, alts)
return _alternatives
def constant_rule(integral):
return ConstantRule(*integral)
def power_rule(integral):
integrand, symbol = integral
base, expt = integrand.as_base_exp()
if symbol not in expt.free_symbols and isinstance(base, Symbol):
if simplify(expt + 1) == 0:
return ReciprocalRule(integrand, symbol, base)
return PowerRule(integrand, symbol, base, expt)
elif symbol not in base.free_symbols and isinstance(expt, Symbol):
rule = ExpRule(integrand, symbol, base, expt)
if fuzzy_not(log(base).is_zero):
return rule
elif log(base).is_zero:
return ConstantRule(1, symbol)
return PiecewiseRule(integrand, symbol, [
(rule, Ne(log(base), 0)),
(ConstantRule(1, symbol), True)
])
def exp_rule(integral):
integrand, symbol = integral
if isinstance(integrand.args[0], Symbol):
return ExpRule(integrand, symbol, E, integrand.args[0])
def orthogonal_poly_rule(integral):
orthogonal_poly_classes = {
jacobi: JacobiRule,
gegenbauer: GegenbauerRule,
chebyshevt: ChebyshevTRule,
chebyshevu: ChebyshevURule,
legendre: LegendreRule,
hermite: HermiteRule,
laguerre: LaguerreRule,
assoc_laguerre: AssocLaguerreRule
}
orthogonal_poly_var_index = {
jacobi: 3,
gegenbauer: 2,
assoc_laguerre: 2
}
integrand, symbol = integral
for klass in orthogonal_poly_classes:
if isinstance(integrand, klass):
var_index = orthogonal_poly_var_index.get(klass, 1)
if (integrand.args[var_index] is symbol and not
any(v.has(symbol) for v in integrand.args[:var_index])):
return orthogonal_poly_classes[klass](integrand, symbol, *integrand.args[:var_index])
_special_function_patterns: list[tuple[Type, Expr, Callable | None, tuple]] = []
_wilds = []
_symbol = Dummy('x')
def special_function_rule(integral):
integrand, symbol = integral
if not _special_function_patterns:
a = Wild('a', exclude=[_symbol], properties=[lambda x: not x.is_zero])
b = Wild('b', exclude=[_symbol])
c = Wild('c', exclude=[_symbol])
d = Wild('d', exclude=[_symbol], properties=[lambda x: not x.is_zero])
e = Wild('e', exclude=[_symbol], properties=[
lambda x: not (x.is_nonnegative and x.is_integer)])
_wilds.extend((a, b, c, d, e))
# patterns consist of a SymPy class, a wildcard expr, an optional
# condition coded as a lambda (when Wild properties are not enough),
# followed by an applicable rule
linear_pattern = a*_symbol + b
quadratic_pattern = a*_symbol**2 + b*_symbol + c
_special_function_patterns.extend((
(Mul, exp(linear_pattern, evaluate=False)/_symbol, None, EiRule),
(Mul, cos(linear_pattern, evaluate=False)/_symbol, None, CiRule),
(Mul, cosh(linear_pattern, evaluate=False)/_symbol, None, ChiRule),
(Mul, sin(linear_pattern, evaluate=False)/_symbol, None, SiRule),
(Mul, sinh(linear_pattern, evaluate=False)/_symbol, None, ShiRule),
(Pow, 1/log(linear_pattern, evaluate=False), None, LiRule),
(exp, exp(quadratic_pattern, evaluate=False), None, ErfRule),
(sin, sin(quadratic_pattern, evaluate=False), None, FresnelSRule),
(cos, cos(quadratic_pattern, evaluate=False), None, FresnelCRule),
(Mul, _symbol**e*exp(a*_symbol, evaluate=False), None, UpperGammaRule),
(Mul, polylog(b, a*_symbol, evaluate=False)/_symbol, None, PolylogRule),
(Pow, 1/sqrt(a - d*sin(_symbol, evaluate=False)**2),
lambda a, d: a != d, EllipticFRule),
(Pow, sqrt(a - d*sin(_symbol, evaluate=False)**2),
lambda a, d: a != d, EllipticERule),
))
_integrand = integrand.subs(symbol, _symbol)
for type_, pattern, constraint, rule in _special_function_patterns:
if isinstance(_integrand, type_):
match = _integrand.match(pattern)
if match:
wild_vals = tuple(match.get(w) for w in _wilds
if match.get(w) is not None)
if constraint is None or constraint(*wild_vals):
return rule(integrand, symbol, *wild_vals)
def _add_degenerate_step(generic_cond, generic_step: Rule, degenerate_step: Rule | None) -> Rule:
if degenerate_step is None:
return generic_step
if isinstance(generic_step, PiecewiseRule):
subfunctions = [(substep, (cond & generic_cond).simplify())
for substep, cond in generic_step.subfunctions]
else:
subfunctions = [(generic_step, generic_cond)]
if isinstance(degenerate_step, PiecewiseRule):
subfunctions += degenerate_step.subfunctions
else:
subfunctions.append((degenerate_step, S.true))
return PiecewiseRule(generic_step.integrand, generic_step.variable, subfunctions)
def nested_pow_rule(integral: IntegralInfo):
# nested (c*(a+b*x)**d)**e
integrand, x = integral
a_ = Wild('a', exclude=[x])
b_ = Wild('b', exclude=[x, 0])
pattern = a_+b_*x
generic_cond = S.true
class NoMatch(Exception):
pass
def _get_base_exp(expr: Expr) -> tuple[Expr, Expr]:
if not expr.has_free(x):
return S.One, S.Zero
if expr.is_Mul:
_, terms = expr.as_coeff_mul()
if not terms:
return S.One, S.Zero
results = [_get_base_exp(term) for term in terms]
bases = {b for b, _ in results}
bases.discard(S.One)
if len(bases) == 1:
return bases.pop(), Add(*(e for _, e in results))
raise NoMatch
if expr.is_Pow:
b, e = expr.base, expr.exp # type: ignore
if e.has_free(x):
raise NoMatch
base_, sub_exp = _get_base_exp(b)
return base_, sub_exp * e
match = expr.match(pattern)
if match:
a, b = match[a_], match[b_]
base_ = x + a/b
nonlocal generic_cond
generic_cond = Ne(b, 0)
return base_, S.One
raise NoMatch
try:
base, exp_ = _get_base_exp(integrand)
except NoMatch:
return
if generic_cond is S.true:
degenerate_step = None
else:
# equivalent with subs(b, 0) but no need to find b
degenerate_step = ConstantRule(integrand.subs(x, 0), x)
generic_step = NestedPowRule(integrand, x, base, exp_)
return _add_degenerate_step(generic_cond, generic_step, degenerate_step)
def inverse_trig_rule(integral: IntegralInfo, degenerate=True):
"""
Set degenerate=False on recursive call where coefficient of quadratic term
is assumed non-zero.
"""
integrand, symbol = integral
base, exp = integrand.as_base_exp()
a = Wild('a', exclude=[symbol])
b = Wild('b', exclude=[symbol])
c = Wild('c', exclude=[symbol, 0])
match = base.match(a + b*symbol + c*symbol**2)
if not match:
return
def make_inverse_trig(RuleClass, a, sign_a, c, sign_c, h) -> Rule:
u_var = Dummy("u")
rewritten = 1/sqrt(sign_a*a + sign_c*c*(symbol-h)**2) # a>0, c>0
quadratic_base = sqrt(c/a)*(symbol-h)
constant = 1/sqrt(c)
u_func = None
if quadratic_base is not symbol:
u_func = quadratic_base
quadratic_base = u_var
standard_form = 1/sqrt(sign_a + sign_c*quadratic_base**2)
substep = RuleClass(standard_form, quadratic_base)
if constant != 1:
substep = ConstantTimesRule(constant*standard_form, symbol, constant, standard_form, substep)
if u_func is not None:
substep = URule(rewritten, symbol, u_var, u_func, substep)
if h != 0:
substep = CompleteSquareRule(integrand, symbol, rewritten, substep)
return substep
a, b, c = [match.get(i, S.Zero) for i in (a, b, c)]
generic_cond = Ne(c, 0)
if not degenerate or generic_cond is S.true:
degenerate_step = None
elif b.is_zero:
degenerate_step = ConstantRule(a ** exp, symbol)
else:
degenerate_step = sqrt_linear_rule(IntegralInfo((a + b * symbol) ** exp, symbol))
if simplify(2*exp + 1) == 0:
h, k = -b/(2*c), a - b**2/(4*c) # rewrite base to k + c*(symbol-h)**2
non_square_cond = Ne(k, 0)
square_step = None
if non_square_cond is not S.true:
square_step = NestedPowRule(1/sqrt(c*(symbol-h)**2), symbol, symbol-h, S.NegativeOne)
if non_square_cond is S.false:
return square_step
generic_step = ReciprocalSqrtQuadraticRule(integrand, symbol, a, b, c)
step = _add_degenerate_step(non_square_cond, generic_step, square_step)
if k.is_real and c.is_real:
# list of ((rule, base_exp, a, sign_a, b, sign_b), condition)
rules = []
for args, cond in ( # don't apply ArccoshRule to x**2-1
((ArcsinRule, k, 1, -c, -1, h), And(k > 0, c < 0)), # 1-x**2
((ArcsinhRule, k, 1, c, 1, h), And(k > 0, c > 0)), # 1+x**2
):
if cond is S.true:
return make_inverse_trig(*args)
if cond is not S.false:
rules.append((make_inverse_trig(*args), cond))
if rules:
if not k.is_positive: # conditions are not thorough, need fall back rule
rules.append((generic_step, S.true))
step = PiecewiseRule(integrand, symbol, rules)
else:
step = generic_step
return _add_degenerate_step(generic_cond, step, degenerate_step)
if exp == S.Half:
step = SqrtQuadraticRule(integrand, symbol, a, b, c)
return _add_degenerate_step(generic_cond, step, degenerate_step)
def add_rule(integral):
integrand, symbol = integral
results = [integral_steps(g, symbol)
for g in integrand.as_ordered_terms()]
return None if None in results else AddRule(integrand, symbol, results)
def mul_rule(integral: IntegralInfo):
integrand, symbol = integral
# Constant times function case
coeff, f = integrand.as_independent(symbol)
if coeff != 1:
next_step = integral_steps(f, symbol)
if next_step is not None:
return ConstantTimesRule(integrand, symbol, coeff, f, next_step)
def _parts_rule(integrand, symbol) -> tuple[Expr, Expr, Expr, Expr, Rule] | None:
# LIATE rule:
# log, inverse trig, algebraic, trigonometric, exponential
def pull_out_algebraic(integrand):
integrand = integrand.cancel().together()
# iterating over Piecewise args would not work here
algebraic = ([] if isinstance(integrand, Piecewise) or not integrand.is_Mul
else [arg for arg in integrand.args if arg.is_algebraic_expr(symbol)])
if algebraic:
u = Mul(*algebraic)
dv = (integrand / u).cancel()
return u, dv
def pull_out_u(*functions) -> Callable[[Expr], tuple[Expr, Expr] | None]:
def pull_out_u_rl(integrand: Expr) -> tuple[Expr, Expr] | None:
if any(integrand.has(f) for f in functions):
args = [arg for arg in integrand.args
if any(isinstance(arg, cls) for cls in functions)]
if args:
u = Mul(*args)
dv = integrand / u
return u, dv
return None
return pull_out_u_rl
liate_rules = [pull_out_u(log), pull_out_u(*inverse_trig_functions),
pull_out_algebraic, pull_out_u(sin, cos),
pull_out_u(exp)]
dummy = Dummy("temporary")
# we can integrate log(x) and atan(x) by setting dv = 1
if isinstance(integrand, (log, *inverse_trig_functions)):
integrand = dummy * integrand
for index, rule in enumerate(liate_rules):
result = rule(integrand)
if result:
u, dv = result
# Don't pick u to be a constant if possible
if symbol not in u.free_symbols and not u.has(dummy):
return None
u = u.subs(dummy, 1)
dv = dv.subs(dummy, 1)
# Don't pick a non-polynomial algebraic to be differentiated
if rule == pull_out_algebraic and not u.is_polynomial(symbol):
return None
# Don't trade one logarithm for another
if isinstance(u, log):
rec_dv = 1/dv
if (rec_dv.is_polynomial(symbol) and
degree(rec_dv, symbol) == 1):
return None
# Can integrate a polynomial times OrthogonalPolynomial
if rule == pull_out_algebraic:
if dv.is_Derivative or dv.has(TrigonometricFunction) or \
isinstance(dv, OrthogonalPolynomial):
v_step = integral_steps(dv, symbol)
if v_step.contains_dont_know():
return None
else:
du = u.diff(symbol)
v = v_step.eval()
return u, dv, v, du, v_step
# make sure dv is amenable to integration
accept = False
if index < 2: # log and inverse trig are usually worth trying
accept = True
elif (rule == pull_out_algebraic and dv.args and
all(isinstance(a, (sin, cos, exp))
for a in dv.args)):
accept = True
else:
for lrule in liate_rules[index + 1:]:
r = lrule(integrand)
if r and r[0].subs(dummy, 1).equals(dv):
accept = True
break
if accept:
du = u.diff(symbol)
v_step = integral_steps(simplify(dv), symbol)
if not v_step.contains_dont_know():
v = v_step.eval()
return u, dv, v, du, v_step
return None
def parts_rule(integral):
integrand, symbol = integral
constant, integrand = integrand.as_coeff_Mul()
result = _parts_rule(integrand, symbol)
steps = []
if result:
u, dv, v, du, v_step = result
debug("u : {}, dv : {}, v : {}, du : {}, v_step: {}".format(u, dv, v, du, v_step))
steps.append(result)
if isinstance(v, Integral):
return
# Set a limit on the number of times u can be used
if isinstance(u, (sin, cos, exp, sinh, cosh)):
cachekey = u.xreplace({symbol: _cache_dummy})
if _parts_u_cache[cachekey] > 2:
return
_parts_u_cache[cachekey] += 1
# Try cyclic integration by parts a few times
for _ in range(4):
debug("Cyclic integration {} with v: {}, du: {}, integrand: {}".format(_, v, du, integrand))
coefficient = ((v * du) / integrand).cancel()
if coefficient == 1:
break
if symbol not in coefficient.free_symbols:
rule = CyclicPartsRule(integrand, symbol,
[PartsRule(None, None, u, dv, v_step, None)
for (u, dv, v, du, v_step) in steps],
(-1) ** len(steps) * coefficient)
if (constant != 1) and rule:
rule = ConstantTimesRule(constant * integrand, symbol, constant, integrand, rule)
return rule
# _parts_rule is sensitive to constants, factor it out
next_constant, next_integrand = (v * du).as_coeff_Mul()
result = _parts_rule(next_integrand, symbol)
if result:
u, dv, v, du, v_step = result
u *= next_constant
du *= next_constant
steps.append((u, dv, v, du, v_step))
else:
break
def make_second_step(steps, integrand):
if steps:
u, dv, v, du, v_step = steps[0]
return PartsRule(integrand, symbol, u, dv, v_step, make_second_step(steps[1:], v * du))
return integral_steps(integrand, symbol)
if steps:
u, dv, v, du, v_step = steps[0]
rule = PartsRule(integrand, symbol, u, dv, v_step, make_second_step(steps[1:], v * du))
if (constant != 1) and rule:
rule = ConstantTimesRule(constant * integrand, symbol, constant, integrand, rule)
return rule
def trig_rule(integral):
integrand, symbol = integral
if integrand == sin(symbol):
return SinRule(integrand, symbol)
if integrand == cos(symbol):
return CosRule(integrand, symbol)
if integrand == sec(symbol)**2:
return Sec2Rule(integrand, symbol)
if integrand == csc(symbol)**2:
return Csc2Rule(integrand, symbol)
if isinstance(integrand, tan):
rewritten = sin(*integrand.args) / cos(*integrand.args)
elif isinstance(integrand, cot):
rewritten = cos(*integrand.args) / sin(*integrand.args)
elif isinstance(integrand, sec):
arg = integrand.args[0]
rewritten = ((sec(arg)**2 + tan(arg) * sec(arg)) /
(sec(arg) + tan(arg)))
elif isinstance(integrand, csc):
arg = integrand.args[0]
rewritten = ((csc(arg)**2 + cot(arg) * csc(arg)) /
(csc(arg) + cot(arg)))
else:
return
return RewriteRule(integrand, symbol, rewritten, integral_steps(rewritten, symbol))
def trig_product_rule(integral: IntegralInfo):
integrand, symbol = integral
if integrand == sec(symbol) * tan(symbol):
return SecTanRule(integrand, symbol)
if integrand == csc(symbol) * cot(symbol):
return CscCotRule(integrand, symbol)
def quadratic_denom_rule(integral):
integrand, symbol = integral
a = Wild('a', exclude=[symbol])
b = Wild('b', exclude=[symbol])
c = Wild('c', exclude=[symbol])
match = integrand.match(a / (b * symbol ** 2 + c))
if match:
a, b, c = match[a], match[b], match[c]
general_rule = ArctanRule(integrand, symbol, a, b, c)
if b.is_extended_real and c.is_extended_real:
positive_cond = c/b > 0
if positive_cond is S.true:
return general_rule
coeff = a/(2*sqrt(-c)*sqrt(b))
constant = sqrt(-c/b)
r1 = 1/(symbol-constant)
r2 = 1/(symbol+constant)
log_steps = [ReciprocalRule(r1, symbol, symbol-constant),
ConstantTimesRule(-r2, symbol, -1, r2, ReciprocalRule(r2, symbol, symbol+constant))]
rewritten = sub = r1 - r2
negative_step = AddRule(sub, symbol, log_steps)
if coeff != 1:
rewritten = Mul(coeff, sub, evaluate=False)
negative_step = ConstantTimesRule(rewritten, symbol, coeff, sub, negative_step)
negative_step = RewriteRule(integrand, symbol, rewritten, negative_step)
if positive_cond is S.false:
return negative_step
return PiecewiseRule(integrand, symbol, [(general_rule, positive_cond), (negative_step, S.true)])
power = PowerRule(integrand, symbol, symbol, -2)
if b != 1:
power = ConstantTimesRule(integrand, symbol, 1/b, symbol**-2, power)
return PiecewiseRule(integrand, symbol, [(general_rule, Ne(c, 0)), (power, True)])
d = Wild('d', exclude=[symbol])
match2 = integrand.match(a / (b * symbol ** 2 + c * symbol + d))
if match2:
b, c = match2[b], match2[c]
if b.is_zero:
return
u = Dummy('u')
u_func = symbol + c/(2*b)
integrand2 = integrand.subs(symbol, u - c / (2*b))
next_step = integral_steps(integrand2, u)
if next_step:
return URule(integrand2, symbol, u, u_func, next_step)
else:
return
e = Wild('e', exclude=[symbol])
match3 = integrand.match((a* symbol + b) / (c * symbol ** 2 + d * symbol + e))
if match3:
a, b, c, d, e = match3[a], match3[b], match3[c], match3[d], match3[e]
if c.is_zero:
return
denominator = c * symbol**2 + d * symbol + e
const = a/(2*c)
numer1 = (2*c*symbol+d)
numer2 = - const*d + b
u = Dummy('u')
step1 = URule(integrand, symbol,
u, denominator, integral_steps(u**(-1), u))
if const != 1:
step1 = ConstantTimesRule(const*numer1/denominator, symbol,
const, numer1/denominator, step1)
if numer2.is_zero:
return step1
step2 = integral_steps(numer2/denominator, symbol)
substeps = AddRule(integrand, symbol, [step1, step2])
rewriten = const*numer1/denominator+numer2/denominator
return RewriteRule(integrand, symbol, rewriten, substeps)
return
def sqrt_linear_rule(integral: IntegralInfo):
"""
Substitute common (a+b*x)**(1/n)
"""
integrand, x = integral
a = Wild('a', exclude=[x])
b = Wild('b', exclude=[x, 0])
a0 = b0 = 0
bases, qs, bs = [], [], []
for pow_ in integrand.find(Pow): # collect all (a+b*x)**(p/q)
base, exp_ = pow_.base, pow_.exp
if exp_.is_Integer or x not in base.free_symbols: # skip 1/x and sqrt(2)
continue
if not exp_.is_Rational: # exclude x**pi
return
match = base.match(a+b*x)
if not match: # skip non-linear
continue # for sqrt(x+sqrt(x)), although base is non-linear, we can still substitute sqrt(x)
a1, b1 = match[a], match[b]
if a0*b1 != a1*b0 or not (b0/b1).is_nonnegative: # cannot transform sqrt(x) to sqrt(x+1) or sqrt(-x)
return
if b0 == 0 or (b0/b1 > 1) is S.true: # choose the latter of sqrt(2*x) and sqrt(x) as representative
a0, b0 = a1, b1
bases.append(base)
bs.append(b1)
qs.append(exp_.q)
if b0 == 0: # no such pattern found
return
q0: Integer = lcm_list(qs)
u_x = (a0 + b0*x)**(1/q0)
u = Dummy("u")
substituted = integrand.subs({base**(S.One/q): (b/b0)**(S.One/q)*u**(q0/q)
for base, b, q in zip(bases, bs, qs)}).subs(x, (u**q0-a0)/b0)
substep = integral_steps(substituted*u**(q0-1)*q0/b0, u)
if not substep.contains_dont_know():
step: Rule = URule(integrand, x, u, u_x, substep)
generic_cond = Ne(b0, 0)
if generic_cond is not S.true: # possible degenerate case
simplified = integrand.subs(dict.fromkeys(bs, 0))
degenerate_step = integral_steps(simplified, x)
step = PiecewiseRule(integrand, x, [(step, generic_cond), (degenerate_step, S.true)])
return step
def sqrt_quadratic_rule(integral: IntegralInfo, degenerate=True):
integrand, x = integral
a = Wild('a', exclude=[x])
b = Wild('b', exclude=[x])
c = Wild('c', exclude=[x, 0])
f = Wild('f')
n = Wild('n', properties=[lambda n: n.is_Integer and n.is_odd])
match = integrand.match(f*sqrt(a+b*x+c*x**2)**n)
if not match:
return
a, b, c, f, n = match[a], match[b], match[c], match[f], match[n]
f_poly = f.as_poly(x)
if f_poly is None:
return
generic_cond = Ne(c, 0)
if not degenerate or generic_cond is S.true:
degenerate_step = None
elif b.is_zero:
degenerate_step = integral_steps(f*sqrt(a)**n, x)
else:
degenerate_step = sqrt_linear_rule(IntegralInfo(f*sqrt(a+b*x)**n, x))
def sqrt_quadratic_denom_rule(numer_poly: Poly, integrand: Expr):
denom = sqrt(a+b*x+c*x**2)
deg = numer_poly.degree()
if deg <= 1:
# integrand == (d+e*x)/sqrt(a+b*x+c*x**2)
e, d = numer_poly.all_coeffs() if deg == 1 else (S.Zero, numer_poly.as_expr())
# rewrite numerator to A*(2*c*x+b) + B
A = e/(2*c)
B = d-A*b
pre_substitute = (2*c*x+b)/denom
constant_step: Rule | None = None
linear_step: Rule | None = None
if A != 0:
u = Dummy("u")
pow_rule = PowerRule(1/sqrt(u), u, u, -S.Half)
linear_step = URule(pre_substitute, x, u, a+b*x+c*x**2, pow_rule)
if A != 1:
linear_step = ConstantTimesRule(A*pre_substitute, x, A, pre_substitute, linear_step)
if B != 0:
constant_step = inverse_trig_rule(IntegralInfo(1/denom, x), degenerate=False)
if B != 1:
constant_step = ConstantTimesRule(B/denom, x, B, 1/denom, constant_step) # type: ignore
if linear_step and constant_step:
add = Add(A*pre_substitute, B/denom, evaluate=False)
step: Rule | None = RewriteRule(integrand, x, add, AddRule(add, x, [linear_step, constant_step]))
else:
step = linear_step or constant_step
else:
coeffs = numer_poly.all_coeffs()
step = SqrtQuadraticDenomRule(integrand, x, a, b, c, coeffs)
return step
if n > 0: # rewrite poly * sqrt(s)**(2*k-1) to poly*s**k / sqrt(s)
numer_poly = f_poly * (a+b*x+c*x**2)**((n+1)/2)
rewritten = numer_poly.as_expr()/sqrt(a+b*x+c*x**2)
substep = sqrt_quadratic_denom_rule(numer_poly, rewritten)
generic_step = RewriteRule(integrand, x, rewritten, substep)
elif n == -1:
generic_step = sqrt_quadratic_denom_rule(f_poly, integrand)
else:
return # todo: handle n < -1 case
return _add_degenerate_step(generic_cond, generic_step, degenerate_step)
def hyperbolic_rule(integral: tuple[Expr, Symbol]):
integrand, symbol = integral
if isinstance(integrand, HyperbolicFunction) and integrand.args[0] == symbol:
if integrand.func == sinh:
return SinhRule(integrand, symbol)
if integrand.func == cosh:
return CoshRule(integrand, symbol)
u = Dummy('u')
if integrand.func == tanh:
rewritten = sinh(symbol)/cosh(symbol)
return RewriteRule(integrand, symbol, rewritten,
URule(rewritten, symbol, u, cosh(symbol), ReciprocalRule(1/u, u, u)))
if integrand.func == coth:
rewritten = cosh(symbol)/sinh(symbol)
return RewriteRule(integrand, symbol, rewritten,
URule(rewritten, symbol, u, sinh(symbol), ReciprocalRule(1/u, u, u)))
else:
rewritten = integrand.rewrite(tanh)
if integrand.func == sech:
return RewriteRule(integrand, symbol, rewritten,
URule(rewritten, symbol, u, tanh(symbol/2),
ArctanRule(2/(u**2 + 1), u, S(2), S.One, S.One)))
if integrand.func == csch:
return RewriteRule(integrand, symbol, rewritten,
URule(rewritten, symbol, u, tanh(symbol/2),
ReciprocalRule(1/u, u, u)))
@cacheit
def make_wilds(symbol):
a = Wild('a', exclude=[symbol])
b = Wild('b', exclude=[symbol])
m = Wild('m', exclude=[symbol], properties=[lambda n: isinstance(n, Integer)])
n = Wild('n', exclude=[symbol], properties=[lambda n: isinstance(n, Integer)])
return a, b, m, n
@cacheit
def sincos_pattern(symbol):
a, b, m, n = make_wilds(symbol)
pattern = sin(a*symbol)**m * cos(b*symbol)**n
return pattern, a, b, m, n
@cacheit
def tansec_pattern(symbol):
a, b, m, n = make_wilds(symbol)
pattern = tan(a*symbol)**m * sec(b*symbol)**n
return pattern, a, b, m, n
@cacheit
def cotcsc_pattern(symbol):
a, b, m, n = make_wilds(symbol)
pattern = cot(a*symbol)**m * csc(b*symbol)**n
return pattern, a, b, m, n
@cacheit
def heaviside_pattern(symbol):
m = Wild('m', exclude=[symbol])
b = Wild('b', exclude=[symbol])
g = Wild('g')
pattern = Heaviside(m*symbol + b) * g
return pattern, m, b, g
def uncurry(func):
def uncurry_rl(args):
return func(*args)
return uncurry_rl
def trig_rewriter(rewrite):
def trig_rewriter_rl(args):
a, b, m, n, integrand, symbol = args
rewritten = rewrite(a, b, m, n, integrand, symbol)
if rewritten != integrand:
return RewriteRule(integrand, symbol, rewritten, integral_steps(rewritten, symbol))
return trig_rewriter_rl
sincos_botheven_condition = uncurry(
lambda a, b, m, n, i, s: m.is_even and n.is_even and
m.is_nonnegative and n.is_nonnegative)
sincos_botheven = trig_rewriter(
lambda a, b, m, n, i, symbol: ( (((1 - cos(2*a*symbol)) / 2) ** (m / 2)) *
(((1 + cos(2*b*symbol)) / 2) ** (n / 2)) ))
sincos_sinodd_condition = uncurry(lambda a, b, m, n, i, s: m.is_odd and m >= 3)
sincos_sinodd = trig_rewriter(
lambda a, b, m, n, i, symbol: ( (1 - cos(a*symbol)**2)**((m - 1) / 2) *
sin(a*symbol) *
cos(b*symbol) ** n))
sincos_cosodd_condition = uncurry(lambda a, b, m, n, i, s: n.is_odd and n >= 3)
sincos_cosodd = trig_rewriter(
lambda a, b, m, n, i, symbol: ( (1 - sin(b*symbol)**2)**((n - 1) / 2) *
cos(b*symbol) *
sin(a*symbol) ** m))
tansec_seceven_condition = uncurry(lambda a, b, m, n, i, s: n.is_even and n >= 4)
tansec_seceven = trig_rewriter(
lambda a, b, m, n, i, symbol: ( (1 + tan(b*symbol)**2) ** (n/2 - 1) *
sec(b*symbol)**2 *
tan(a*symbol) ** m ))
tansec_tanodd_condition = uncurry(lambda a, b, m, n, i, s: m.is_odd)
tansec_tanodd = trig_rewriter(
lambda a, b, m, n, i, symbol: ( (sec(a*symbol)**2 - 1) ** ((m - 1) / 2) *
tan(a*symbol) *
sec(b*symbol) ** n ))
tan_tansquared_condition = uncurry(lambda a, b, m, n, i, s: m == 2 and n == 0)
tan_tansquared = trig_rewriter(
lambda a, b, m, n, i, symbol: ( sec(a*symbol)**2 - 1))
cotcsc_csceven_condition = uncurry(lambda a, b, m, n, i, s: n.is_even and n >= 4)
cotcsc_csceven = trig_rewriter(
lambda a, b, m, n, i, symbol: ( (1 + cot(b*symbol)**2) ** (n/2 - 1) *
csc(b*symbol)**2 *
cot(a*symbol) ** m ))
cotcsc_cotodd_condition = uncurry(lambda a, b, m, n, i, s: m.is_odd)
cotcsc_cotodd = trig_rewriter(
lambda a, b, m, n, i, symbol: ( (csc(a*symbol)**2 - 1) ** ((m - 1) / 2) *
cot(a*symbol) *
csc(b*symbol) ** n ))
def trig_sincos_rule(integral):
integrand, symbol = integral
if any(integrand.has(f) for f in (sin, cos)):
pattern, a, b, m, n = sincos_pattern(symbol)
match = integrand.match(pattern)
if not match:
return
return multiplexer({
sincos_botheven_condition: sincos_botheven,
sincos_sinodd_condition: sincos_sinodd,
sincos_cosodd_condition: sincos_cosodd
})(tuple(
[match.get(i, S.Zero) for i in (a, b, m, n)] +
[integrand, symbol]))
def trig_tansec_rule(integral):
integrand, symbol = integral
integrand = integrand.subs({
1 / cos(symbol): sec(symbol)
})
if any(integrand.has(f) for f in (tan, sec)):
pattern, a, b, m, n = tansec_pattern(symbol)
match = integrand.match(pattern)
if not match:
return
return multiplexer({
tansec_tanodd_condition: tansec_tanodd,
tansec_seceven_condition: tansec_seceven,
tan_tansquared_condition: tan_tansquared
})(tuple(
[match.get(i, S.Zero) for i in (a, b, m, n)] +
[integrand, symbol]))
def trig_cotcsc_rule(integral):
integrand, symbol = integral
integrand = integrand.subs({
1 / sin(symbol): csc(symbol),
1 / tan(symbol): cot(symbol),
cos(symbol) / tan(symbol): cot(symbol)
})
if any(integrand.has(f) for f in (cot, csc)):
pattern, a, b, m, n = cotcsc_pattern(symbol)
match = integrand.match(pattern)
if not match:
return
return multiplexer({
cotcsc_cotodd_condition: cotcsc_cotodd,
cotcsc_csceven_condition: cotcsc_csceven
})(tuple(
[match.get(i, S.Zero) for i in (a, b, m, n)] +
[integrand, symbol]))
def trig_sindouble_rule(integral):
integrand, symbol = integral
a = Wild('a', exclude=[sin(2*symbol)])
match = integrand.match(sin(2*symbol)*a)
if match:
sin_double = 2*sin(symbol)*cos(symbol)/sin(2*symbol)
return integral_steps(integrand * sin_double, symbol)
def trig_powers_products_rule(integral):
return do_one(null_safe(trig_sincos_rule),
null_safe(trig_tansec_rule),
null_safe(trig_cotcsc_rule),
null_safe(trig_sindouble_rule))(integral)
def trig_substitution_rule(integral):
integrand, symbol = integral
A = Wild('a', exclude=[0, symbol])
B = Wild('b', exclude=[0, symbol])
theta = Dummy("theta")
target_pattern = A + B*symbol**2
matches = integrand.find(target_pattern)
for expr in matches:
match = expr.match(target_pattern)
a = match.get(A, S.Zero)
b = match.get(B, S.Zero)
a_positive = ((a.is_number and a > 0) or a.is_positive)
b_positive = ((b.is_number and b > 0) or b.is_positive)
a_negative = ((a.is_number and a < 0) or a.is_negative)
b_negative = ((b.is_number and b < 0) or b.is_negative)
x_func = None
if a_positive and b_positive:
# a**2 + b*x**2. Assume sec(theta) > 0, -pi/2 < theta < pi/2
x_func = (sqrt(a)/sqrt(b)) * tan(theta)
# Do not restrict the domain: tan(theta) takes on any real
# value on the interval -pi/2 < theta < pi/2 so x takes on
# any value
restriction = True
elif a_positive and b_negative:
# a**2 - b*x**2. Assume cos(theta) > 0, -pi/2 < theta < pi/2
constant = sqrt(a)/sqrt(-b)
x_func = constant * sin(theta)
restriction = And(symbol > -constant, symbol < constant)
elif a_negative and b_positive:
# b*x**2 - a**2. Assume sin(theta) > 0, 0 < theta < pi
constant = sqrt(-a)/sqrt(b)
x_func = constant * sec(theta)
restriction = And(symbol > -constant, symbol < constant)
if x_func:
# Manually simplify sqrt(trig(theta)**2) to trig(theta)
# Valid due to assumed domain restriction
substitutions = {}
for f in [sin, cos, tan,
sec, csc, cot]:
substitutions[sqrt(f(theta)**2)] = f(theta)
substitutions[sqrt(f(theta)**(-2))] = 1/f(theta)
replaced = integrand.subs(symbol, x_func).trigsimp()
replaced = manual_subs(replaced, substitutions)
if not replaced.has(symbol):
replaced *= manual_diff(x_func, theta)
replaced = replaced.trigsimp()
secants = replaced.find(1/cos(theta))
if secants:
replaced = replaced.xreplace({
1/cos(theta): sec(theta)
})
substep = integral_steps(replaced, theta)
if not substep.contains_dont_know():
return TrigSubstitutionRule(integrand, symbol,
theta, x_func, replaced, substep, restriction)
def heaviside_rule(integral):
integrand, symbol = integral
pattern, m, b, g = heaviside_pattern(symbol)
match = integrand.match(pattern)
if match and 0 != match[g]:
# f = Heaviside(m*x + b)*g
substep = integral_steps(match[g], symbol)
m, b = match[m], match[b]
return HeavisideRule(integrand, symbol, m*symbol + b, -b/m, substep)
def dirac_delta_rule(integral: IntegralInfo):
integrand, x = integral
if len(integrand.args) == 1:
n = S.Zero
else:
n = integrand.args[1]
if not n.is_Integer or n < 0:
return
a, b = Wild('a', exclude=[x]), Wild('b', exclude=[x, 0])
match = integrand.args[0].match(a+b*x)
if not match:
return
a, b = match[a], match[b]
generic_cond = Ne(b, 0)
if generic_cond is S.true:
degenerate_step = None
else:
degenerate_step = ConstantRule(DiracDelta(a, n), x)
generic_step = DiracDeltaRule(integrand, x, n, a, b)
return _add_degenerate_step(generic_cond, generic_step, degenerate_step)
def substitution_rule(integral):
integrand, symbol = integral
u_var = Dummy("u")
substitutions = find_substitutions(integrand, symbol, u_var)
count = 0
if substitutions:
debug("List of Substitution Rules")
ways = []
for u_func, c, substituted in substitutions:
subrule = integral_steps(substituted, u_var)
count = count + 1
debug("Rule {}: {}".format(count, subrule))
if subrule.contains_dont_know():
continue
if simplify(c - 1) != 0:
_, denom = c.as_numer_denom()
if subrule:
subrule = ConstantTimesRule(c * substituted, u_var, c, substituted, subrule)
if denom.free_symbols:
piecewise = []
could_be_zero = []
if isinstance(denom, Mul):
could_be_zero = denom.args
else:
could_be_zero.append(denom)
for expr in could_be_zero:
if not fuzzy_not(expr.is_zero):
substep = integral_steps(manual_subs(integrand, expr, 0), symbol)
if substep:
piecewise.append((
substep,
Eq(expr, 0)
))
piecewise.append((subrule, True))
subrule = PiecewiseRule(substituted, symbol, piecewise)
ways.append(URule(integrand, symbol, u_var, u_func, subrule))
if len(ways) > 1:
return AlternativeRule(integrand, symbol, ways)
elif ways:
return ways[0]
partial_fractions_rule = rewriter(
lambda integrand, symbol: integrand.is_rational_function(),
lambda integrand, symbol: integrand.apart(symbol))
cancel_rule = rewriter(
# lambda integrand, symbol: integrand.is_algebraic_expr(),
# lambda integrand, symbol: isinstance(integrand, Mul),
lambda integrand, symbol: True,
lambda integrand, symbol: integrand.cancel())
distribute_expand_rule = rewriter(
lambda integrand, symbol: (
isinstance(integrand, (Pow, Mul)) or all(arg.is_Pow or arg.is_polynomial(symbol) for arg in integrand.args)),
lambda integrand, symbol: integrand.expand())
trig_expand_rule = rewriter(
# If there are trig functions with different arguments, expand them
lambda integrand, symbol: (
len({a.args[0] for a in integrand.atoms(TrigonometricFunction)}) > 1),
lambda integrand, symbol: integrand.expand(trig=True))
def derivative_rule(integral):
integrand = integral[0]
diff_variables = integrand.variables
undifferentiated_function = integrand.expr
integrand_variables = undifferentiated_function.free_symbols
if integral.symbol in integrand_variables:
if integral.symbol in diff_variables:
return DerivativeRule(*integral)
else:
return DontKnowRule(integrand, integral.symbol)
else:
return ConstantRule(*integral)
def rewrites_rule(integral):
integrand, symbol = integral
if integrand.match(1/cos(symbol)):
rewritten = integrand.subs(1/cos(symbol), sec(symbol))
return RewriteRule(integrand, symbol, rewritten, integral_steps(rewritten, symbol))
def fallback_rule(integral):
return DontKnowRule(*integral)
# Cache is used to break cyclic integrals.
# Need to use the same dummy variable in cached expressions for them to match.
# Also record "u" of integration by parts, to avoid infinite repetition.
_integral_cache: dict[Expr, Expr | None] = {}
_parts_u_cache: dict[Expr, int] = defaultdict(int)
_cache_dummy = Dummy("z")
def integral_steps(integrand, symbol, **options):
"""Returns the steps needed to compute an integral.
Explanation
===========
This function attempts to mirror what a student would do by hand as
closely as possible.
SymPy Gamma uses this to provide a step-by-step explanation of an
integral. The code it uses to format the results of this function can be
found at
https://github.com/sympy/sympy_gamma/blob/master/app/logic/intsteps.py.
Examples
========
>>> from sympy import exp, sin
>>> from sympy.integrals.manualintegrate import integral_steps
>>> from sympy.abc import x
>>> print(repr(integral_steps(exp(x) / (1 + exp(2 * x)), x))) \
# doctest: +NORMALIZE_WHITESPACE
URule(integrand=exp(x)/(exp(2*x) + 1), variable=x, u_var=_u, u_func=exp(x),
substep=ArctanRule(integrand=1/(_u**2 + 1), variable=_u, a=1, b=1, c=1))
>>> print(repr(integral_steps(sin(x), x))) \
# doctest: +NORMALIZE_WHITESPACE
SinRule(integrand=sin(x), variable=x)
>>> print(repr(integral_steps((x**2 + 3)**2, x))) \
# doctest: +NORMALIZE_WHITESPACE
RewriteRule(integrand=(x**2 + 3)**2, variable=x, rewritten=x**4 + 6*x**2 + 9,
substep=AddRule(integrand=x**4 + 6*x**2 + 9, variable=x,
substeps=[PowerRule(integrand=x**4, variable=x, base=x, exp=4),
ConstantTimesRule(integrand=6*x**2, variable=x, constant=6, other=x**2,
substep=PowerRule(integrand=x**2, variable=x, base=x, exp=2)),
ConstantRule(integrand=9, variable=x)]))
Returns
=======
rule : Rule
The first step; most rules have substeps that must also be
considered. These substeps can be evaluated using ``manualintegrate``
to obtain a result.
"""
cachekey = integrand.xreplace({symbol: _cache_dummy})
if cachekey in _integral_cache:
if _integral_cache[cachekey] is None:
# Stop this attempt, because it leads around in a loop
return DontKnowRule(integrand, symbol)
else:
# TODO: This is for future development, as currently
# _integral_cache gets no values other than None
return (_integral_cache[cachekey].xreplace(_cache_dummy, symbol),
symbol)
else:
_integral_cache[cachekey] = None
integral = IntegralInfo(integrand, symbol)
def key(integral):
integrand = integral.integrand
if symbol not in integrand.free_symbols:
return Number
for cls in (Symbol, TrigonometricFunction, OrthogonalPolynomial):
if isinstance(integrand, cls):
return cls
return type(integrand)
def integral_is_subclass(*klasses):
def _integral_is_subclass(integral):
k = key(integral)
return k and issubclass(k, klasses)
return _integral_is_subclass
result = do_one(
null_safe(special_function_rule),
null_safe(switch(key, {
Pow: do_one(null_safe(power_rule), null_safe(inverse_trig_rule),
null_safe(sqrt_linear_rule),
null_safe(quadratic_denom_rule)),
Symbol: power_rule,
exp: exp_rule,
Add: add_rule,
Mul: do_one(null_safe(mul_rule), null_safe(trig_product_rule),
null_safe(heaviside_rule), null_safe(quadratic_denom_rule),
null_safe(sqrt_linear_rule),
null_safe(sqrt_quadratic_rule)),
Derivative: derivative_rule,
TrigonometricFunction: trig_rule,
Heaviside: heaviside_rule,
DiracDelta: dirac_delta_rule,
OrthogonalPolynomial: orthogonal_poly_rule,
Number: constant_rule
})),
do_one(
null_safe(trig_rule),
null_safe(hyperbolic_rule),
null_safe(alternatives(
rewrites_rule,
substitution_rule,
condition(
integral_is_subclass(Mul, Pow),
partial_fractions_rule),
condition(
integral_is_subclass(Mul, Pow),
cancel_rule),
condition(
integral_is_subclass(Mul, log,
*inverse_trig_functions),
parts_rule),
condition(
integral_is_subclass(Mul, Pow),
distribute_expand_rule),
trig_powers_products_rule,
trig_expand_rule
)),
null_safe(condition(integral_is_subclass(Mul, Pow), nested_pow_rule)),
null_safe(trig_substitution_rule)
),
fallback_rule)(integral)
del _integral_cache[cachekey]
return result
def manualintegrate(f, var):
"""manualintegrate(f, var)
Explanation
===========
Compute indefinite integral of a single variable using an algorithm that
resembles what a student would do by hand.
Unlike :func:`~.integrate`, var can only be a single symbol.
Examples
========
>>> from sympy import sin, cos, tan, exp, log, integrate
>>> from sympy.integrals.manualintegrate import manualintegrate
>>> from sympy.abc import x
>>> manualintegrate(1 / x, x)
log(x)
>>> integrate(1/x)
log(x)
>>> manualintegrate(log(x), x)
x*log(x) - x
>>> integrate(log(x))
x*log(x) - x
>>> manualintegrate(exp(x) / (1 + exp(2 * x)), x)
atan(exp(x))
>>> integrate(exp(x) / (1 + exp(2 * x)))
RootSum(4*_z**2 + 1, Lambda(_i, _i*log(2*_i + exp(x))))
>>> manualintegrate(cos(x)**4 * sin(x), x)
-cos(x)**5/5
>>> integrate(cos(x)**4 * sin(x), x)
-cos(x)**5/5
>>> manualintegrate(cos(x)**4 * sin(x)**3, x)
cos(x)**7/7 - cos(x)**5/5
>>> integrate(cos(x)**4 * sin(x)**3, x)
cos(x)**7/7 - cos(x)**5/5
>>> manualintegrate(tan(x), x)
-log(cos(x))
>>> integrate(tan(x), x)
-log(cos(x))
See Also
========
sympy.integrals.integrals.integrate
sympy.integrals.integrals.Integral.doit
sympy.integrals.integrals.Integral
"""
result = integral_steps(f, var).eval()
# Clear the cache of u-parts
_parts_u_cache.clear()
# If we got Piecewise with two parts, put generic first
if isinstance(result, Piecewise) and len(result.args) == 2:
cond = result.args[0][1]
if isinstance(cond, Eq) and result.args[1][1] == True:
result = result.func(
(result.args[1][0], Ne(*cond.args)),
(result.args[0][0], True))
return result
PK ]ZZZ�*eK�; �; sympy/integrals/meijerint.py"""
Integrate functions by rewriting them as Meijer G-functions.
There are three user-visible functions that can be used by other parts of the
sympy library to solve various integration problems:
- meijerint_indefinite
- meijerint_definite
- meijerint_inversion
They can be used to compute, respectively, indefinite integrals, definite
integrals over intervals of the real line, and inverse laplace-type integrals
(from c-I*oo to c+I*oo). See the respective docstrings for details.
The main references for this are:
[L] Luke, Y. L. (1969), The Special Functions and Their Approximations,
Volume 1
[R] Kelly B. Roach. Meijer G Function Representations.
In: Proceedings of the 1997 International Symposium on Symbolic and
Algebraic Computation, pages 205-211, New York, 1997. ACM.
[P] A. P. Prudnikov, Yu. A. Brychkov and O. I. Marichev (1990).
Integrals and Series: More Special Functions, Vol. 3,.
Gordon and Breach Science Publisher
"""
from __future__ import annotations
import itertools
from sympy import SYMPY_DEBUG
from sympy.core import S, Expr
from sympy.core.add import Add
from sympy.core.basic import Basic
from sympy.core.cache import cacheit
from sympy.core.containers import Tuple
from sympy.core.exprtools import factor_terms
from sympy.core.function import (expand, expand_mul, expand_power_base,
expand_trig, Function)
from sympy.core.mul import Mul
from sympy.core.intfunc import ilcm
from sympy.core.numbers import Rational, pi
from sympy.core.relational import Eq, Ne, _canonical_coeff
from sympy.core.sorting import default_sort_key, ordered
from sympy.core.symbol import Dummy, symbols, Wild, Symbol
from sympy.core.sympify import sympify
from sympy.functions.combinatorial.factorials import factorial
from sympy.functions.elementary.complexes import (re, im, arg, Abs, sign,
unpolarify, polarify, polar_lift, principal_branch, unbranched_argument,
periodic_argument)
from sympy.functions.elementary.exponential import exp, exp_polar, log
from sympy.functions.elementary.integers import ceiling
from sympy.functions.elementary.hyperbolic import (cosh, sinh,
_rewrite_hyperbolics_as_exp, HyperbolicFunction)
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.elementary.piecewise import Piecewise, piecewise_fold
from sympy.functions.elementary.trigonometric import (cos, sin, sinc,
TrigonometricFunction)
from sympy.functions.special.bessel import besselj, bessely, besseli, besselk
from sympy.functions.special.delta_functions import DiracDelta, Heaviside
from sympy.functions.special.elliptic_integrals import elliptic_k, elliptic_e
from sympy.functions.special.error_functions import (erf, erfc, erfi, Ei,
expint, Si, Ci, Shi, Chi, fresnels, fresnelc)
from sympy.functions.special.gamma_functions import gamma
from sympy.functions.special.hyper import hyper, meijerg
from sympy.functions.special.singularity_functions import SingularityFunction
from .integrals import Integral
from sympy.logic.boolalg import And, Or, BooleanAtom, Not, BooleanFunction
from sympy.polys import cancel, factor
from sympy.utilities.iterables import multiset_partitions
from sympy.utilities.misc import debug as _debug
from sympy.utilities.misc import debugf as _debugf
# keep this at top for easy reference
z = Dummy('z')
def _has(res, *f):
# return True if res has f; in the case of Piecewise
# only return True if *all* pieces have f
res = piecewise_fold(res)
if getattr(res, 'is_Piecewise', False):
return all(_has(i, *f) for i in res.args)
return res.has(*f)
def _create_lookup_table(table):
""" Add formulae for the function -> meijerg lookup table. """
def wild(n):
return Wild(n, exclude=[z])
p, q, a, b, c = list(map(wild, 'pqabc'))
n = Wild('n', properties=[lambda x: x.is_Integer and x > 0])
t = p*z**q
def add(formula, an, ap, bm, bq, arg=t, fac=S.One, cond=True, hint=True):
table.setdefault(_mytype(formula, z), []).append((formula,
[(fac, meijerg(an, ap, bm, bq, arg))], cond, hint))
def addi(formula, inst, cond, hint=True):
table.setdefault(
_mytype(formula, z), []).append((formula, inst, cond, hint))
def constant(a):
return [(a, meijerg([1], [], [], [0], z)),
(a, meijerg([], [1], [0], [], z))]
table[()] = [(a, constant(a), True, True)]
# [P], Section 8.
class IsNonPositiveInteger(Function):
@classmethod
def eval(cls, arg):
arg = unpolarify(arg)
if arg.is_Integer is True:
return arg <= 0
# Section 8.4.2
# TODO this needs more polar_lift (c/f entry for exp)
add(Heaviside(t - b)*(t - b)**(a - 1), [a], [], [], [0], t/b,
gamma(a)*b**(a - 1), And(b > 0))
add(Heaviside(b - t)*(b - t)**(a - 1), [], [a], [0], [], t/b,
gamma(a)*b**(a - 1), And(b > 0))
add(Heaviside(z - (b/p)**(1/q))*(t - b)**(a - 1), [a], [], [], [0], t/b,
gamma(a)*b**(a - 1), And(b > 0))
add(Heaviside((b/p)**(1/q) - z)*(b - t)**(a - 1), [], [a], [0], [], t/b,
gamma(a)*b**(a - 1), And(b > 0))
add((b + t)**(-a), [1 - a], [], [0], [], t/b, b**(-a)/gamma(a),
hint=Not(IsNonPositiveInteger(a)))
add(Abs(b - t)**(-a), [1 - a], [(1 - a)/2], [0], [(1 - a)/2], t/b,
2*sin(pi*a/2)*gamma(1 - a)*Abs(b)**(-a), re(a) < 1)
add((t**a - b**a)/(t - b), [0, a], [], [0, a], [], t/b,
b**(a - 1)*sin(a*pi)/pi)
# 12
def A1(r, sign, nu):
return pi**Rational(-1, 2)*(-sign*nu/2)**(1 - 2*r)
def tmpadd(r, sgn):
# XXX the a**2 is bad for matching
add((sqrt(a**2 + t) + sgn*a)**b/(a**2 + t)**r,
[(1 + b)/2, 1 - 2*r + b/2], [],
[(b - sgn*b)/2], [(b + sgn*b)/2], t/a**2,
a**(b - 2*r)*A1(r, sgn, b))
tmpadd(0, 1)
tmpadd(0, -1)
tmpadd(S.Half, 1)
tmpadd(S.Half, -1)
# 13
def tmpadd(r, sgn):
add((sqrt(a + p*z**q) + sgn*sqrt(p)*z**(q/2))**b/(a + p*z**q)**r,
[1 - r + sgn*b/2], [1 - r - sgn*b/2], [0, S.Half], [],
p*z**q/a, a**(b/2 - r)*A1(r, sgn, b))
tmpadd(0, 1)
tmpadd(0, -1)
tmpadd(S.Half, 1)
tmpadd(S.Half, -1)
# (those after look obscure)
# Section 8.4.3
add(exp(polar_lift(-1)*t), [], [], [0], [])
# TODO can do sin^n, sinh^n by expansion ... where?
# 8.4.4 (hyperbolic functions)
add(sinh(t), [], [1], [S.Half], [1, 0], t**2/4, pi**Rational(3, 2))
add(cosh(t), [], [S.Half], [0], [S.Half, S.Half], t**2/4, pi**Rational(3, 2))
# Section 8.4.5
# TODO can do t + a. but can also do by expansion... (XXX not really)
add(sin(t), [], [], [S.Half], [0], t**2/4, sqrt(pi))
add(cos(t), [], [], [0], [S.Half], t**2/4, sqrt(pi))
# Section 8.4.6 (sinc function)
add(sinc(t), [], [], [0], [Rational(-1, 2)], t**2/4, sqrt(pi)/2)
# Section 8.5.5
def make_log1(subs):
N = subs[n]
return [(S.NegativeOne**N*factorial(N),
meijerg([], [1]*(N + 1), [0]*(N + 1), [], t))]
def make_log2(subs):
N = subs[n]
return [(factorial(N),
meijerg([1]*(N + 1), [], [], [0]*(N + 1), t))]
# TODO these only hold for positive p, and can be made more general
# but who uses log(x)*Heaviside(a-x) anyway ...
# TODO also it would be nice to derive them recursively ...
addi(log(t)**n*Heaviside(1 - t), make_log1, True)
addi(log(t)**n*Heaviside(t - 1), make_log2, True)
def make_log3(subs):
return make_log1(subs) + make_log2(subs)
addi(log(t)**n, make_log3, True)
addi(log(t + a),
constant(log(a)) + [(S.One, meijerg([1, 1], [], [1], [0], t/a))],
True)
addi(log(Abs(t - a)), constant(log(Abs(a))) +
[(pi, meijerg([1, 1], [S.Half], [1], [0, S.Half], t/a))],
True)
# TODO log(x)/(x+a) and log(x)/(x-1) can also be done. should they
# be derivable?
# TODO further formulae in this section seem obscure
# Sections 8.4.9-10
# TODO
# Section 8.4.11
addi(Ei(t),
constant(-S.ImaginaryUnit*pi) + [(S.NegativeOne, meijerg([], [1], [0, 0], [],
t*polar_lift(-1)))],
True)
# Section 8.4.12
add(Si(t), [1], [], [S.Half], [0, 0], t**2/4, sqrt(pi)/2)
add(Ci(t), [], [1], [0, 0], [S.Half], t**2/4, -sqrt(pi)/2)
# Section 8.4.13
add(Shi(t), [S.Half], [], [0], [Rational(-1, 2), Rational(-1, 2)], polar_lift(-1)*t**2/4,
t*sqrt(pi)/4)
add(Chi(t), [], [S.Half, 1], [0, 0], [S.Half, S.Half], t**2/4, -
pi**S('3/2')/2)
# generalized exponential integral
add(expint(a, t), [], [a], [a - 1, 0], [], t)
# Section 8.4.14
add(erf(t), [1], [], [S.Half], [0], t**2, 1/sqrt(pi))
# TODO exp(-x)*erf(I*x) does not work
add(erfc(t), [], [1], [0, S.Half], [], t**2, 1/sqrt(pi))
# This formula for erfi(z) yields a wrong(?) minus sign
#add(erfi(t), [1], [], [S.Half], [0], -t**2, I/sqrt(pi))
add(erfi(t), [S.Half], [], [0], [Rational(-1, 2)], -t**2, t/sqrt(pi))
# Fresnel Integrals
add(fresnels(t), [1], [], [Rational(3, 4)], [0, Rational(1, 4)], pi**2*t**4/16, S.Half)
add(fresnelc(t), [1], [], [Rational(1, 4)], [0, Rational(3, 4)], pi**2*t**4/16, S.Half)
##### bessel-type functions #####
# Section 8.4.19
add(besselj(a, t), [], [], [a/2], [-a/2], t**2/4)
# all of the following are derivable
#add(sin(t)*besselj(a, t), [Rational(1, 4), Rational(3, 4)], [], [(1+a)/2],
# [-a/2, a/2, (1-a)/2], t**2, 1/sqrt(2))
#add(cos(t)*besselj(a, t), [Rational(1, 4), Rational(3, 4)], [], [a/2],
# [-a/2, (1+a)/2, (1-a)/2], t**2, 1/sqrt(2))
#add(besselj(a, t)**2, [S.Half], [], [a], [-a, 0], t**2, 1/sqrt(pi))
#add(besselj(a, t)*besselj(b, t), [0, S.Half], [], [(a + b)/2],
# [-(a+b)/2, (a - b)/2, (b - a)/2], t**2, 1/sqrt(pi))
# Section 8.4.20
add(bessely(a, t), [], [-(a + 1)/2], [a/2, -a/2], [-(a + 1)/2], t**2/4)
# TODO all of the following should be derivable
#add(sin(t)*bessely(a, t), [Rational(1, 4), Rational(3, 4)], [(1 - a - 1)/2],
# [(1 + a)/2, (1 - a)/2], [(1 - a - 1)/2, (1 - 1 - a)/2, (1 - 1 + a)/2],
# t**2, 1/sqrt(2))
#add(cos(t)*bessely(a, t), [Rational(1, 4), Rational(3, 4)], [(0 - a - 1)/2],
# [(0 + a)/2, (0 - a)/2], [(0 - a - 1)/2, (1 - 0 - a)/2, (1 - 0 + a)/2],
# t**2, 1/sqrt(2))
#add(besselj(a, t)*bessely(b, t), [0, S.Half], [(a - b - 1)/2],
# [(a + b)/2, (a - b)/2], [(a - b - 1)/2, -(a + b)/2, (b - a)/2],
# t**2, 1/sqrt(pi))
#addi(bessely(a, t)**2,
# [(2/sqrt(pi), meijerg([], [S.Half, S.Half - a], [0, a, -a],
# [S.Half - a], t**2)),
# (1/sqrt(pi), meijerg([S.Half], [], [a], [-a, 0], t**2))],
# True)
#addi(bessely(a, t)*bessely(b, t),
# [(2/sqrt(pi), meijerg([], [0, S.Half, (1 - a - b)/2],
# [(a + b)/2, (a - b)/2, (b - a)/2, -(a + b)/2],
# [(1 - a - b)/2], t**2)),
# (1/sqrt(pi), meijerg([0, S.Half], [], [(a + b)/2],
# [-(a + b)/2, (a - b)/2, (b - a)/2], t**2))],
# True)
# Section 8.4.21 ?
# Section 8.4.22
add(besseli(a, t), [], [(1 + a)/2], [a/2], [-a/2, (1 + a)/2], t**2/4, pi)
# TODO many more formulas. should all be derivable
# Section 8.4.23
add(besselk(a, t), [], [], [a/2, -a/2], [], t**2/4, S.Half)
# TODO many more formulas. should all be derivable
# Complete elliptic integrals K(z) and E(z)
add(elliptic_k(t), [S.Half, S.Half], [], [0], [0], -t, S.Half)
add(elliptic_e(t), [S.Half, 3*S.Half], [], [0], [0], -t, Rational(-1, 2)/2)
####################################################################
# First some helper functions.
####################################################################
from sympy.utilities.timeutils import timethis
timeit = timethis('meijerg')
def _mytype(f: Basic, x: Symbol) -> tuple[type[Basic], ...]:
""" Create a hashable entity describing the type of f. """
def key(x: type[Basic]) -> tuple[int, int, str]:
return x.class_key()
if x not in f.free_symbols:
return ()
elif f.is_Function:
return type(f),
return tuple(sorted((t for a in f.args for t in _mytype(a, x)), key=key))
class _CoeffExpValueError(ValueError):
"""
Exception raised by _get_coeff_exp, for internal use only.
"""
pass
def _get_coeff_exp(expr, x):
"""
When expr is known to be of the form c*x**b, with c and/or b possibly 1,
return c, b.
Examples
========
>>> from sympy.abc import x, a, b
>>> from sympy.integrals.meijerint import _get_coeff_exp
>>> _get_coeff_exp(a*x**b, x)
(a, b)
>>> _get_coeff_exp(x, x)
(1, 1)
>>> _get_coeff_exp(2*x, x)
(2, 1)
>>> _get_coeff_exp(x**3, x)
(1, 3)
"""
from sympy.simplify import powsimp
(c, m) = expand_power_base(powsimp(expr)).as_coeff_mul(x)
if not m:
return c, S.Zero
[m] = m
if m.is_Pow:
if m.base != x:
raise _CoeffExpValueError('expr not of form a*x**b')
return c, m.exp
elif m == x:
return c, S.One
else:
raise _CoeffExpValueError('expr not of form a*x**b: %s' % expr)
def _exponents(expr, x):
"""
Find the exponents of ``x`` (not including zero) in ``expr``.
Examples
========
>>> from sympy.integrals.meijerint import _exponents
>>> from sympy.abc import x, y
>>> from sympy import sin
>>> _exponents(x, x)
{1}
>>> _exponents(x**2, x)
{2}
>>> _exponents(x**2 + x, x)
{1, 2}
>>> _exponents(x**3*sin(x + x**y) + 1/x, x)
{-1, 1, 3, y}
"""
def _exponents_(expr, x, res):
if expr == x:
res.update([1])
return
if expr.is_Pow and expr.base == x:
res.update([expr.exp])
return
for argument in expr.args:
_exponents_(argument, x, res)
res = set()
_exponents_(expr, x, res)
return res
def _functions(expr, x):
""" Find the types of functions in expr, to estimate the complexity. """
return {e.func for e in expr.atoms(Function) if x in e.free_symbols}
def _find_splitting_points(expr, x):
"""
Find numbers a such that a linear substitution x -> x + a would
(hopefully) simplify expr.
Examples
========
>>> from sympy.integrals.meijerint import _find_splitting_points as fsp
>>> from sympy import sin
>>> from sympy.abc import x
>>> fsp(x, x)
{0}
>>> fsp((x-1)**3, x)
{1}
>>> fsp(sin(x+3)*x, x)
{-3, 0}
"""
p, q = [Wild(n, exclude=[x]) for n in 'pq']
def compute_innermost(expr, res):
if not isinstance(expr, Expr):
return
m = expr.match(p*x + q)
if m and m[p] != 0:
res.add(-m[q]/m[p])
return
if expr.is_Atom:
return
for argument in expr.args:
compute_innermost(argument, res)
innermost = set()
compute_innermost(expr, innermost)
return innermost
def _split_mul(f, x):
"""
Split expression ``f`` into fac, po, g, where fac is a constant factor,
po = x**s for some s independent of s, and g is "the rest".
Examples
========
>>> from sympy.integrals.meijerint import _split_mul
>>> from sympy import sin
>>> from sympy.abc import s, x
>>> _split_mul((3*x)**s*sin(x**2)*x, x)
(3**s, x*x**s, sin(x**2))
"""
fac = S.One
po = S.One
g = S.One
f = expand_power_base(f)
args = Mul.make_args(f)
for a in args:
if a == x:
po *= x
elif x not in a.free_symbols:
fac *= a
else:
if a.is_Pow and x not in a.exp.free_symbols:
c, t = a.base.as_coeff_mul(x)
if t != (x,):
c, t = expand_mul(a.base).as_coeff_mul(x)
if t == (x,):
po *= x**a.exp
fac *= unpolarify(polarify(c**a.exp, subs=False))
continue
g *= a
return fac, po, g
def _mul_args(f):
"""
Return a list ``L`` such that ``Mul(*L) == f``.
If ``f`` is not a ``Mul`` or ``Pow``, ``L=[f]``.
If ``f=g**n`` for an integer ``n``, ``L=[g]*n``.
If ``f`` is a ``Mul``, ``L`` comes from applying ``_mul_args`` to all factors of ``f``.
"""
args = Mul.make_args(f)
gs = []
for g in args:
if g.is_Pow and g.exp.is_Integer:
n = g.exp
base = g.base
if n < 0:
n = -n
base = 1/base
gs += [base]*n
else:
gs.append(g)
return gs
def _mul_as_two_parts(f):
"""
Find all the ways to split ``f`` into a product of two terms.
Return None on failure.
Explanation
===========
Although the order is canonical from multiset_partitions, this is
not necessarily the best order to process the terms. For example,
if the case of len(gs) == 2 is removed and multiset is allowed to
sort the terms, some tests fail.
Examples
========
>>> from sympy.integrals.meijerint import _mul_as_two_parts
>>> from sympy import sin, exp, ordered
>>> from sympy.abc import x
>>> list(ordered(_mul_as_two_parts(x*sin(x)*exp(x))))
[(x, exp(x)*sin(x)), (x*exp(x), sin(x)), (x*sin(x), exp(x))]
"""
gs = _mul_args(f)
if len(gs) < 2:
return None
if len(gs) == 2:
return [tuple(gs)]
return [(Mul(*x), Mul(*y)) for (x, y) in multiset_partitions(gs, 2)]
def _inflate_g(g, n):
""" Return C, h such that h is a G function of argument z**n and
g = C*h. """
# TODO should this be a method of meijerg?
# See: [L, page 150, equation (5)]
def inflate(params, n):
""" (a1, .., ak) -> (a1/n, (a1+1)/n, ..., (ak + n-1)/n) """
return [(a + i)/n for a, i in itertools.product(params, range(n))]
v = S(len(g.ap) - len(g.bq))
C = n**(1 + g.nu + v/2)
C /= (2*pi)**((n - 1)*g.delta)
return C, meijerg(inflate(g.an, n), inflate(g.aother, n),
inflate(g.bm, n), inflate(g.bother, n),
g.argument**n * n**(n*v))
def _flip_g(g):
""" Turn the G function into one of inverse argument
(i.e. G(1/x) -> G'(x)) """
# See [L], section 5.2
def tr(l):
return [1 - a for a in l]
return meijerg(tr(g.bm), tr(g.bother), tr(g.an), tr(g.aother), 1/g.argument)
def _inflate_fox_h(g, a):
r"""
Let d denote the integrand in the definition of the G function ``g``.
Consider the function H which is defined in the same way, but with
integrand d/Gamma(a*s) (contour conventions as usual).
If ``a`` is rational, the function H can be written as C*G, for a constant C
and a G-function G.
This function returns C, G.
"""
if a < 0:
return _inflate_fox_h(_flip_g(g), -a)
p = S(a.p)
q = S(a.q)
# We use the substitution s->qs, i.e. inflate g by q. We are left with an
# extra factor of Gamma(p*s), for which we use Gauss' multiplication
# theorem.
D, g = _inflate_g(g, q)
z = g.argument
D /= (2*pi)**((1 - p)/2)*p**Rational(-1, 2)
z /= p**p
bs = [(n + 1)/p for n in range(p)]
return D, meijerg(g.an, g.aother, g.bm, list(g.bother) + bs, z)
_dummies: dict[tuple[str, str], Dummy] = {}
def _dummy(name, token, expr, **kwargs):
"""
Return a dummy. This will return the same dummy if the same token+name is
requested more than once, and it is not already in expr.
This is for being cache-friendly.
"""
d = _dummy_(name, token, **kwargs)
if d in expr.free_symbols:
return Dummy(name, **kwargs)
return d
def _dummy_(name, token, **kwargs):
"""
Return a dummy associated to name and token. Same effect as declaring
it globally.
"""
global _dummies
if not (name, token) in _dummies:
_dummies[(name, token)] = Dummy(name, **kwargs)
return _dummies[(name, token)]
def _is_analytic(f, x):
""" Check if f(x), when expressed using G functions on the positive reals,
will in fact agree with the G functions almost everywhere """
return not any(x in expr.free_symbols for expr in f.atoms(Heaviside, Abs))
def _condsimp(cond, first=True):
"""
Do naive simplifications on ``cond``.
Explanation
===========
Note that this routine is completely ad-hoc, simplification rules being
added as need arises rather than following any logical pattern.
Examples
========
>>> from sympy.integrals.meijerint import _condsimp as simp
>>> from sympy import Or, Eq
>>> from sympy.abc import x, y
>>> simp(Or(x < y, Eq(x, y)))
x <= y
"""
if first:
cond = cond.replace(lambda _: _.is_Relational, _canonical_coeff)
first = False
if not isinstance(cond, BooleanFunction):
return cond
p, q, r = symbols('p q r', cls=Wild)
# transforms tests use 0, 4, 5 and 11-14
# meijer tests use 0, 2, 11, 14
# joint_rv uses 6, 7
rules = [
(Or(p < q, Eq(p, q)), p <= q), # 0
# The next two obviously are instances of a general pattern, but it is
# easier to spell out the few cases we care about.
(And(Abs(arg(p)) <= pi, Abs(arg(p) - 2*pi) <= pi),
Eq(arg(p) - pi, 0)), # 1
(And(Abs(2*arg(p) + pi) <= pi, Abs(2*arg(p) - pi) <= pi),
Eq(arg(p), 0)), # 2
(And(Abs(2*arg(p) + pi) < pi, Abs(2*arg(p) - pi) <= pi),
S.false), # 3
(And(Abs(arg(p) - pi/2) <= pi/2, Abs(arg(p) + pi/2) <= pi/2),
Eq(arg(p), 0)), # 4
(And(Abs(arg(p) - pi/2) <= pi/2, Abs(arg(p) + pi/2) < pi/2),
S.false), # 5
(And(Abs(arg(p**2/2 + 1)) < pi, Ne(Abs(arg(p**2/2 + 1)), pi)),
S.true), # 6
(Or(Abs(arg(p**2/2 + 1)) < pi, Ne(1/(p**2/2 + 1), 0)),
S.true), # 7
(And(Abs(unbranched_argument(p)) <= pi,
Abs(unbranched_argument(exp_polar(-2*pi*S.ImaginaryUnit)*p)) <= pi),
Eq(unbranched_argument(exp_polar(-S.ImaginaryUnit*pi)*p), 0)), # 8
(And(Abs(unbranched_argument(p)) <= pi/2,
Abs(unbranched_argument(exp_polar(-pi*S.ImaginaryUnit)*p)) <= pi/2),
Eq(unbranched_argument(exp_polar(-S.ImaginaryUnit*pi/2)*p), 0)), # 9
(Or(p <= q, And(p < q, r)), p <= q), # 10
(Ne(p**2, 1) & (p**2 > 1), p**2 > 1), # 11
(Ne(1/p, 1) & (cos(Abs(arg(p)))*Abs(p) > 1), Abs(p) > 1), # 12
(Ne(p, 2) & (cos(Abs(arg(p)))*Abs(p) > 2), Abs(p) > 2), # 13
((Abs(arg(p)) < pi/2) & (cos(Abs(arg(p)))*sqrt(Abs(p**2)) > 1), p**2 > 1), # 14
]
cond = cond.func(*[_condsimp(_, first) for _ in cond.args])
change = True
while change:
change = False
for irule, (fro, to) in enumerate(rules):
if fro.func != cond.func:
continue
for n, arg1 in enumerate(cond.args):
if r in fro.args[0].free_symbols:
m = arg1.match(fro.args[1])
num = 1
else:
num = 0
m = arg1.match(fro.args[0])
if not m:
continue
otherargs = [x.subs(m) for x in fro.args[:num] + fro.args[num + 1:]]
otherlist = [n]
for arg2 in otherargs:
for k, arg3 in enumerate(cond.args):
if k in otherlist:
continue
if arg2 == arg3:
otherlist += [k]
break
if isinstance(arg3, And) and arg2.args[1] == r and \
isinstance(arg2, And) and arg2.args[0] in arg3.args:
otherlist += [k]
break
if isinstance(arg3, And) and arg2.args[0] == r and \
isinstance(arg2, And) and arg2.args[1] in arg3.args:
otherlist += [k]
break
if len(otherlist) != len(otherargs) + 1:
continue
newargs = [arg_ for (k, arg_) in enumerate(cond.args)
if k not in otherlist] + [to.subs(m)]
if SYMPY_DEBUG:
if irule not in (0, 2, 4, 5, 6, 7, 11, 12, 13, 14):
print('used new rule:', irule)
cond = cond.func(*newargs)
change = True
break
# final tweak
def rel_touchup(rel):
if rel.rel_op != '==' or rel.rhs != 0:
return rel
# handle Eq(*, 0)
LHS = rel.lhs
m = LHS.match(arg(p)**q)
if not m:
m = LHS.match(unbranched_argument(polar_lift(p)**q))
if not m:
if isinstance(LHS, periodic_argument) and not LHS.args[0].is_polar \
and LHS.args[1] is S.Infinity:
return (LHS.args[0] > 0)
return rel
return (m[p] > 0)
cond = cond.replace(lambda _: _.is_Relational, rel_touchup)
if SYMPY_DEBUG:
print('_condsimp: ', cond)
return cond
def _eval_cond(cond):
""" Re-evaluate the conditions. """
if isinstance(cond, bool):
return cond
return _condsimp(cond.doit())
####################################################################
# Now the "backbone" functions to do actual integration.
####################################################################
def _my_principal_branch(expr, period, full_pb=False):
""" Bring expr nearer to its principal branch by removing superfluous
factors.
This function does *not* guarantee to yield the principal branch,
to avoid introducing opaque principal_branch() objects,
unless full_pb=True. """
res = principal_branch(expr, period)
if not full_pb:
res = res.replace(principal_branch, lambda x, y: x)
return res
def _rewrite_saxena_1(fac, po, g, x):
"""
Rewrite the integral fac*po*g dx, from zero to infinity, as
integral fac*G, where G has argument a*x. Note po=x**s.
Return fac, G.
"""
_, s = _get_coeff_exp(po, x)
a, b = _get_coeff_exp(g.argument, x)
period = g.get_period()
a = _my_principal_branch(a, period)
# We substitute t = x**b.
C = fac/(Abs(b)*a**((s + 1)/b - 1))
# Absorb a factor of (at)**((1 + s)/b - 1).
def tr(l):
return [a + (1 + s)/b - 1 for a in l]
return C, meijerg(tr(g.an), tr(g.aother), tr(g.bm), tr(g.bother),
a*x)
def _check_antecedents_1(g, x, helper=False):
r"""
Return a condition under which the mellin transform of g exists.
Any power of x has already been absorbed into the G function,
so this is just $\int_0^\infty g\, dx$.
See [L, section 5.6.1]. (Note that s=1.)
If ``helper`` is True, only check if the MT exists at infinity, i.e. if
$\int_1^\infty g\, dx$ exists.
"""
# NOTE if you update these conditions, please update the documentation as well
delta = g.delta
eta, _ = _get_coeff_exp(g.argument, x)
m, n, p, q = S([len(g.bm), len(g.an), len(g.ap), len(g.bq)])
if p > q:
def tr(l):
return [1 - x for x in l]
return _check_antecedents_1(meijerg(tr(g.bm), tr(g.bother),
tr(g.an), tr(g.aother), x/eta),
x)
tmp = [-re(b) < 1 for b in g.bm] + [1 < 1 - re(a) for a in g.an]
cond_3 = And(*tmp)
tmp += [-re(b) < 1 for b in g.bother]
tmp += [1 < 1 - re(a) for a in g.aother]
cond_3_star = And(*tmp)
cond_4 = (-re(g.nu) + (q + 1 - p)/2 > q - p)
def debug(*msg):
_debug(*msg)
def debugf(string, arg):
_debugf(string, arg)
debug('Checking antecedents for 1 function:')
debugf(' delta=%s, eta=%s, m=%s, n=%s, p=%s, q=%s',
(delta, eta, m, n, p, q))
debugf(' ap = %s, %s', (list(g.an), list(g.aother)))
debugf(' bq = %s, %s', (list(g.bm), list(g.bother)))
debugf(' cond_3=%s, cond_3*=%s, cond_4=%s', (cond_3, cond_3_star, cond_4))
conds = []
# case 1
case1 = []
tmp1 = [1 <= n, p < q, 1 <= m]
tmp2 = [1 <= p, 1 <= m, Eq(q, p + 1), Not(And(Eq(n, 0), Eq(m, p + 1)))]
tmp3 = [1 <= p, Eq(q, p)]
for k in range(ceiling(delta/2) + 1):
tmp3 += [Ne(Abs(unbranched_argument(eta)), (delta - 2*k)*pi)]
tmp = [delta > 0, Abs(unbranched_argument(eta)) < delta*pi]
extra = [Ne(eta, 0), cond_3]
if helper:
extra = []
for t in [tmp1, tmp2, tmp3]:
case1 += [And(*(t + tmp + extra))]
conds += case1
debug(' case 1:', case1)
# case 2
extra = [cond_3]
if helper:
extra = []
case2 = [And(Eq(n, 0), p + 1 <= m, m <= q,
Abs(unbranched_argument(eta)) < delta*pi, *extra)]
conds += case2
debug(' case 2:', case2)
# case 3
extra = [cond_3, cond_4]
if helper:
extra = []
case3 = [And(p < q, 1 <= m, delta > 0, Eq(Abs(unbranched_argument(eta)), delta*pi),
*extra)]
case3 += [And(p <= q - 2, Eq(delta, 0), Eq(Abs(unbranched_argument(eta)), 0), *extra)]
conds += case3
debug(' case 3:', case3)
# TODO altered cases 4-7
# extra case from wofram functions site:
# (reproduced verbatim from Prudnikov, section 2.24.2)
# https://functions.wolfram.com/HypergeometricFunctions/MeijerG/21/02/01/
case_extra = []
case_extra += [Eq(p, q), Eq(delta, 0), Eq(unbranched_argument(eta), 0), Ne(eta, 0)]
if not helper:
case_extra += [cond_3]
s = []
for a, b in zip(g.ap, g.bq):
s += [b - a]
case_extra += [re(Add(*s)) < 0]
case_extra = And(*case_extra)
conds += [case_extra]
debug(' extra case:', [case_extra])
case_extra_2 = [And(delta > 0, Abs(unbranched_argument(eta)) < delta*pi)]
if not helper:
case_extra_2 += [cond_3]
case_extra_2 = And(*case_extra_2)
conds += [case_extra_2]
debug(' second extra case:', [case_extra_2])
# TODO This leaves only one case from the three listed by Prudnikov.
# Investigate if these indeed cover everything; if so, remove the rest.
return Or(*conds)
def _int0oo_1(g, x):
r"""
Evaluate $\int_0^\infty g\, dx$ using G functions,
assuming the necessary conditions are fulfilled.
Examples
========
>>> from sympy.abc import a, b, c, d, x, y
>>> from sympy import meijerg
>>> from sympy.integrals.meijerint import _int0oo_1
>>> _int0oo_1(meijerg([a], [b], [c], [d], x*y), x)
gamma(-a)*gamma(c + 1)/(y*gamma(-d)*gamma(b + 1))
"""
from sympy.simplify import gammasimp
# See [L, section 5.6.1]. Note that s=1.
eta, _ = _get_coeff_exp(g.argument, x)
res = 1/eta
# XXX TODO we should reduce order first
for b in g.bm:
res *= gamma(b + 1)
for a in g.an:
res *= gamma(1 - a - 1)
for b in g.bother:
res /= gamma(1 - b - 1)
for a in g.aother:
res /= gamma(a + 1)
return gammasimp(unpolarify(res))
def _rewrite_saxena(fac, po, g1, g2, x, full_pb=False):
"""
Rewrite the integral ``fac*po*g1*g2`` from 0 to oo in terms of G
functions with argument ``c*x``.
Explanation
===========
Return C, f1, f2 such that integral C f1 f2 from 0 to infinity equals
integral fac ``po``, ``g1``, ``g2`` from 0 to infinity.
Examples
========
>>> from sympy.integrals.meijerint import _rewrite_saxena
>>> from sympy.abc import s, t, m
>>> from sympy import meijerg
>>> g1 = meijerg([], [], [0], [], s*t)
>>> g2 = meijerg([], [], [m/2], [-m/2], t**2/4)
>>> r = _rewrite_saxena(1, t**0, g1, g2, t)
>>> r[0]
s/(4*sqrt(pi))
>>> r[1]
meijerg(((), ()), ((-1/2, 0), ()), s**2*t/4)
>>> r[2]
meijerg(((), ()), ((m/2,), (-m/2,)), t/4)
"""
def pb(g):
a, b = _get_coeff_exp(g.argument, x)
per = g.get_period()
return meijerg(g.an, g.aother, g.bm, g.bother,
_my_principal_branch(a, per, full_pb)*x**b)
_, s = _get_coeff_exp(po, x)
_, b1 = _get_coeff_exp(g1.argument, x)
_, b2 = _get_coeff_exp(g2.argument, x)
if (b1 < 0) == True:
b1 = -b1
g1 = _flip_g(g1)
if (b2 < 0) == True:
b2 = -b2
g2 = _flip_g(g2)
if not b1.is_Rational or not b2.is_Rational:
return
m1, n1 = b1.p, b1.q
m2, n2 = b2.p, b2.q
tau = ilcm(m1*n2, m2*n1)
r1 = tau//(m1*n2)
r2 = tau//(m2*n1)
C1, g1 = _inflate_g(g1, r1)
C2, g2 = _inflate_g(g2, r2)
g1 = pb(g1)
g2 = pb(g2)
fac *= C1*C2
a1, b = _get_coeff_exp(g1.argument, x)
a2, _ = _get_coeff_exp(g2.argument, x)
# arbitrarily tack on the x**s part to g1
# TODO should we try both?
exp = (s + 1)/b - 1
fac = fac/(Abs(b) * a1**exp)
def tr(l):
return [a + exp for a in l]
g1 = meijerg(tr(g1.an), tr(g1.aother), tr(g1.bm), tr(g1.bother), a1*x)
g2 = meijerg(g2.an, g2.aother, g2.bm, g2.bother, a2*x)
from sympy.simplify import powdenest
return powdenest(fac, polar=True), g1, g2
def _check_antecedents(g1, g2, x):
""" Return a condition under which the integral theorem applies. """
# Yes, this is madness.
# XXX TODO this is a testing *nightmare*
# NOTE if you update these conditions, please update the documentation as well
# The following conditions are found in
# [P], Section 2.24.1
#
# They are also reproduced (verbatim!) at
# https://functions.wolfram.com/HypergeometricFunctions/MeijerG/21/02/03/
#
# Note: k=l=r=alpha=1
sigma, _ = _get_coeff_exp(g1.argument, x)
omega, _ = _get_coeff_exp(g2.argument, x)
s, t, u, v = S([len(g1.bm), len(g1.an), len(g1.ap), len(g1.bq)])
m, n, p, q = S([len(g2.bm), len(g2.an), len(g2.ap), len(g2.bq)])
bstar = s + t - (u + v)/2
cstar = m + n - (p + q)/2
rho = g1.nu + (u - v)/2 + 1
mu = g2.nu + (p - q)/2 + 1
phi = q - p - (v - u)
eta = 1 - (v - u) - mu - rho
psi = (pi*(q - m - n) + Abs(unbranched_argument(omega)))/(q - p)
theta = (pi*(v - s - t) + Abs(unbranched_argument(sigma)))/(v - u)
_debug('Checking antecedents:')
_debugf(' sigma=%s, s=%s, t=%s, u=%s, v=%s, b*=%s, rho=%s',
(sigma, s, t, u, v, bstar, rho))
_debugf(' omega=%s, m=%s, n=%s, p=%s, q=%s, c*=%s, mu=%s,',
(omega, m, n, p, q, cstar, mu))
_debugf(' phi=%s, eta=%s, psi=%s, theta=%s', (phi, eta, psi, theta))
def _c1():
for g in [g1, g2]:
for i, j in itertools.product(g.an, g.bm):
diff = i - j
if diff.is_integer and diff.is_positive:
return False
return True
c1 = _c1()
c2 = And(*[re(1 + i + j) > 0 for i in g1.bm for j in g2.bm])
c3 = And(*[re(1 + i + j) < 1 + 1 for i in g1.an for j in g2.an])
c4 = And(*[(p - q)*re(1 + i - 1) - re(mu) > Rational(-3, 2) for i in g1.an])
c5 = And(*[(p - q)*re(1 + i) - re(mu) > Rational(-3, 2) for i in g1.bm])
c6 = And(*[(u - v)*re(1 + i - 1) - re(rho) > Rational(-3, 2) for i in g2.an])
c7 = And(*[(u - v)*re(1 + i) - re(rho) > Rational(-3, 2) for i in g2.bm])
c8 = (Abs(phi) + 2*re((rho - 1)*(q - p) + (v - u)*(q - p) + (mu -
1)*(v - u)) > 0)
c9 = (Abs(phi) - 2*re((rho - 1)*(q - p) + (v - u)*(q - p) + (mu -
1)*(v - u)) > 0)
c10 = (Abs(unbranched_argument(sigma)) < bstar*pi)
c11 = Eq(Abs(unbranched_argument(sigma)), bstar*pi)
c12 = (Abs(unbranched_argument(omega)) < cstar*pi)
c13 = Eq(Abs(unbranched_argument(omega)), cstar*pi)
# The following condition is *not* implemented as stated on the wolfram
# function site. In the book of Prudnikov there is an additional part
# (the And involving re()). However, I only have this book in russian, and
# I don't read any russian. The following condition is what other people
# have told me it means.
# Worryingly, it is different from the condition implemented in REDUCE.
# The REDUCE implementation:
# https://reduce-algebra.svn.sourceforge.net/svnroot/reduce-algebra/trunk/packages/defint/definta.red
# (search for tst14)
# The Wolfram alpha version:
# https://functions.wolfram.com/HypergeometricFunctions/MeijerG/21/02/03/03/0014/
z0 = exp(-(bstar + cstar)*pi*S.ImaginaryUnit)
zos = unpolarify(z0*omega/sigma)
zso = unpolarify(z0*sigma/omega)
if zos == 1/zso:
c14 = And(Eq(phi, 0), bstar + cstar <= 1,
Or(Ne(zos, 1), re(mu + rho + v - u) < 1,
re(mu + rho + q - p) < 1))
else:
def _cond(z):
'''Returns True if abs(arg(1-z)) < pi, avoiding arg(0).
Explanation
===========
If ``z`` is 1 then arg is NaN. This raises a
TypeError on `NaN < pi`. Previously this gave `False` so
this behavior has been hardcoded here but someone should
check if this NaN is more serious! This NaN is triggered by
test_meijerint() in test_meijerint.py:
`meijerint_definite(exp(x), x, 0, I)`
'''
return z != 1 and Abs(arg(1 - z)) < pi
c14 = And(Eq(phi, 0), bstar - 1 + cstar <= 0,
Or(And(Ne(zos, 1), _cond(zos)),
And(re(mu + rho + v - u) < 1, Eq(zos, 1))))
c14_alt = And(Eq(phi, 0), cstar - 1 + bstar <= 0,
Or(And(Ne(zso, 1), _cond(zso)),
And(re(mu + rho + q - p) < 1, Eq(zso, 1))))
# Since r=k=l=1, in our case there is c14_alt which is the same as calling
# us with (g1, g2) = (g2, g1). The conditions below enumerate all cases
# (i.e. we don't have to try arguments reversed by hand), and indeed try
# all symmetric cases. (i.e. whenever there is a condition involving c14,
# there is also a dual condition which is exactly what we would get when g1,
# g2 were interchanged, *but c14 was unaltered*).
# Hence the following seems correct:
c14 = Or(c14, c14_alt)
'''
When `c15` is NaN (e.g. from `psi` being NaN as happens during
'test_issue_4992' and/or `theta` is NaN as in 'test_issue_6253',
both in `test_integrals.py`) the comparison to 0 formerly gave False
whereas now an error is raised. To keep the old behavior, the value
of NaN is replaced with False but perhaps a closer look at this condition
should be made: XXX how should conditions leading to c15=NaN be handled?
'''
try:
lambda_c = (q - p)*Abs(omega)**(1/(q - p))*cos(psi) \
+ (v - u)*Abs(sigma)**(1/(v - u))*cos(theta)
# the TypeError might be raised here, e.g. if lambda_c is NaN
if _eval_cond(lambda_c > 0) != False:
c15 = (lambda_c > 0)
else:
def lambda_s0(c1, c2):
return c1*(q - p)*Abs(omega)**(1/(q - p))*sin(psi) \
+ c2*(v - u)*Abs(sigma)**(1/(v - u))*sin(theta)
lambda_s = Piecewise(
((lambda_s0(+1, +1)*lambda_s0(-1, -1)),
And(Eq(unbranched_argument(sigma), 0), Eq(unbranched_argument(omega), 0))),
(lambda_s0(sign(unbranched_argument(omega)), +1)*lambda_s0(sign(unbranched_argument(omega)), -1),
And(Eq(unbranched_argument(sigma), 0), Ne(unbranched_argument(omega), 0))),
(lambda_s0(+1, sign(unbranched_argument(sigma)))*lambda_s0(-1, sign(unbranched_argument(sigma))),
And(Ne(unbranched_argument(sigma), 0), Eq(unbranched_argument(omega), 0))),
(lambda_s0(sign(unbranched_argument(omega)), sign(unbranched_argument(sigma))), True))
tmp = [lambda_c > 0,
And(Eq(lambda_c, 0), Ne(lambda_s, 0), re(eta) > -1),
And(Eq(lambda_c, 0), Eq(lambda_s, 0), re(eta) > 0)]
c15 = Or(*tmp)
except TypeError:
c15 = False
for cond, i in [(c1, 1), (c2, 2), (c3, 3), (c4, 4), (c5, 5), (c6, 6),
(c7, 7), (c8, 8), (c9, 9), (c10, 10), (c11, 11),
(c12, 12), (c13, 13), (c14, 14), (c15, 15)]:
_debugf(' c%s: %s', (i, cond))
# We will return Or(*conds)
conds = []
def pr(count):
_debugf(' case %s: %s', (count, conds[-1]))
conds += [And(m*n*s*t != 0, bstar.is_positive is True, cstar.is_positive is True, c1, c2, c3, c10,
c12)] # 1
pr(1)
conds += [And(Eq(u, v), Eq(bstar, 0), cstar.is_positive is True, sigma.is_positive is True, re(rho) < 1,
c1, c2, c3, c12)] # 2
pr(2)
conds += [And(Eq(p, q), Eq(cstar, 0), bstar.is_positive is True, omega.is_positive is True, re(mu) < 1,
c1, c2, c3, c10)] # 3
pr(3)
conds += [And(Eq(p, q), Eq(u, v), Eq(bstar, 0), Eq(cstar, 0),
sigma.is_positive is True, omega.is_positive is True, re(mu) < 1, re(rho) < 1,
Ne(sigma, omega), c1, c2, c3)] # 4
pr(4)
conds += [And(Eq(p, q), Eq(u, v), Eq(bstar, 0), Eq(cstar, 0),
sigma.is_positive is True, omega.is_positive is True, re(mu + rho) < 1,
Ne(omega, sigma), c1, c2, c3)] # 5
pr(5)
conds += [And(p > q, s.is_positive is True, bstar.is_positive is True, cstar >= 0,
c1, c2, c3, c5, c10, c13)] # 6
pr(6)
conds += [And(p < q, t.is_positive is True, bstar.is_positive is True, cstar >= 0,
c1, c2, c3, c4, c10, c13)] # 7
pr(7)
conds += [And(u > v, m.is_positive is True, cstar.is_positive is True, bstar >= 0,
c1, c2, c3, c7, c11, c12)] # 8
pr(8)
conds += [And(u < v, n.is_positive is True, cstar.is_positive is True, bstar >= 0,
c1, c2, c3, c6, c11, c12)] # 9
pr(9)
conds += [And(p > q, Eq(u, v), Eq(bstar, 0), cstar >= 0, sigma.is_positive is True,
re(rho) < 1, c1, c2, c3, c5, c13)] # 10
pr(10)
conds += [And(p < q, Eq(u, v), Eq(bstar, 0), cstar >= 0, sigma.is_positive is True,
re(rho) < 1, c1, c2, c3, c4, c13)] # 11
pr(11)
conds += [And(Eq(p, q), u > v, bstar >= 0, Eq(cstar, 0), omega.is_positive is True,
re(mu) < 1, c1, c2, c3, c7, c11)] # 12
pr(12)
conds += [And(Eq(p, q), u < v, bstar >= 0, Eq(cstar, 0), omega.is_positive is True,
re(mu) < 1, c1, c2, c3, c6, c11)] # 13
pr(13)
conds += [And(p < q, u > v, bstar >= 0, cstar >= 0,
c1, c2, c3, c4, c7, c11, c13)] # 14
pr(14)
conds += [And(p > q, u < v, bstar >= 0, cstar >= 0,
c1, c2, c3, c5, c6, c11, c13)] # 15
pr(15)
conds += [And(p > q, u > v, bstar >= 0, cstar >= 0,
c1, c2, c3, c5, c7, c8, c11, c13, c14)] # 16
pr(16)
conds += [And(p < q, u < v, bstar >= 0, cstar >= 0,
c1, c2, c3, c4, c6, c9, c11, c13, c14)] # 17
pr(17)
conds += [And(Eq(t, 0), s.is_positive is True, bstar.is_positive is True, phi.is_positive is True, c1, c2, c10)] # 18
pr(18)
conds += [And(Eq(s, 0), t.is_positive is True, bstar.is_positive is True, phi.is_negative is True, c1, c3, c10)] # 19
pr(19)
conds += [And(Eq(n, 0), m.is_positive is True, cstar.is_positive is True, phi.is_negative is True, c1, c2, c12)] # 20
pr(20)
conds += [And(Eq(m, 0), n.is_positive is True, cstar.is_positive is True, phi.is_positive is True, c1, c3, c12)] # 21
pr(21)
conds += [And(Eq(s*t, 0), bstar.is_positive is True, cstar.is_positive is True,
c1, c2, c3, c10, c12)] # 22
pr(22)
conds += [And(Eq(m*n, 0), bstar.is_positive is True, cstar.is_positive is True,
c1, c2, c3, c10, c12)] # 23
pr(23)
# The following case is from [Luke1969]. As far as I can tell, it is *not*
# covered by Prudnikov's.
# Let G1 and G2 be the two G-functions. Suppose the integral exists from
# 0 to a > 0 (this is easy the easy part), that G1 is exponential decay at
# infinity, and that the mellin transform of G2 exists.
# Then the integral exists.
mt1_exists = _check_antecedents_1(g1, x, helper=True)
mt2_exists = _check_antecedents_1(g2, x, helper=True)
conds += [And(mt2_exists, Eq(t, 0), u < s, bstar.is_positive is True, c10, c1, c2, c3)]
pr('E1')
conds += [And(mt2_exists, Eq(s, 0), v < t, bstar.is_positive is True, c10, c1, c2, c3)]
pr('E2')
conds += [And(mt1_exists, Eq(n, 0), p < m, cstar.is_positive is True, c12, c1, c2, c3)]
pr('E3')
conds += [And(mt1_exists, Eq(m, 0), q < n, cstar.is_positive is True, c12, c1, c2, c3)]
pr('E4')
# Let's short-circuit if this worked ...
# the rest is corner-cases and terrible to read.
r = Or(*conds)
if _eval_cond(r) != False:
return r
conds += [And(m + n > p, Eq(t, 0), Eq(phi, 0), s.is_positive is True, bstar.is_positive is True, cstar.is_negative is True,
Abs(unbranched_argument(omega)) < (m + n - p + 1)*pi,
c1, c2, c10, c14, c15)] # 24
pr(24)
conds += [And(m + n > q, Eq(s, 0), Eq(phi, 0), t.is_positive is True, bstar.is_positive is True, cstar.is_negative is True,
Abs(unbranched_argument(omega)) < (m + n - q + 1)*pi,
c1, c3, c10, c14, c15)] # 25
pr(25)
conds += [And(Eq(p, q - 1), Eq(t, 0), Eq(phi, 0), s.is_positive is True, bstar.is_positive is True,
cstar >= 0, cstar*pi < Abs(unbranched_argument(omega)),
c1, c2, c10, c14, c15)] # 26
pr(26)
conds += [And(Eq(p, q + 1), Eq(s, 0), Eq(phi, 0), t.is_positive is True, bstar.is_positive is True,
cstar >= 0, cstar*pi < Abs(unbranched_argument(omega)),
c1, c3, c10, c14, c15)] # 27
pr(27)
conds += [And(p < q - 1, Eq(t, 0), Eq(phi, 0), s.is_positive is True, bstar.is_positive is True,
cstar >= 0, cstar*pi < Abs(unbranched_argument(omega)),
Abs(unbranched_argument(omega)) < (m + n - p + 1)*pi,
c1, c2, c10, c14, c15)] # 28
pr(28)
conds += [And(
p > q + 1, Eq(s, 0), Eq(phi, 0), t.is_positive is True, bstar.is_positive is True, cstar >= 0,
cstar*pi < Abs(unbranched_argument(omega)),
Abs(unbranched_argument(omega)) < (m + n - q + 1)*pi,
c1, c3, c10, c14, c15)] # 29
pr(29)
conds += [And(Eq(n, 0), Eq(phi, 0), s + t > 0, m.is_positive is True, cstar.is_positive is True, bstar.is_negative is True,
Abs(unbranched_argument(sigma)) < (s + t - u + 1)*pi,
c1, c2, c12, c14, c15)] # 30
pr(30)
conds += [And(Eq(m, 0), Eq(phi, 0), s + t > v, n.is_positive is True, cstar.is_positive is True, bstar.is_negative is True,
Abs(unbranched_argument(sigma)) < (s + t - v + 1)*pi,
c1, c3, c12, c14, c15)] # 31
pr(31)
conds += [And(Eq(n, 0), Eq(phi, 0), Eq(u, v - 1), m.is_positive is True, cstar.is_positive is True,
bstar >= 0, bstar*pi < Abs(unbranched_argument(sigma)),
Abs(unbranched_argument(sigma)) < (bstar + 1)*pi,
c1, c2, c12, c14, c15)] # 32
pr(32)
conds += [And(Eq(m, 0), Eq(phi, 0), Eq(u, v + 1), n.is_positive is True, cstar.is_positive is True,
bstar >= 0, bstar*pi < Abs(unbranched_argument(sigma)),
Abs(unbranched_argument(sigma)) < (bstar + 1)*pi,
c1, c3, c12, c14, c15)] # 33
pr(33)
conds += [And(
Eq(n, 0), Eq(phi, 0), u < v - 1, m.is_positive is True, cstar.is_positive is True, bstar >= 0,
bstar*pi < Abs(unbranched_argument(sigma)),
Abs(unbranched_argument(sigma)) < (s + t - u + 1)*pi,
c1, c2, c12, c14, c15)] # 34
pr(34)
conds += [And(
Eq(m, 0), Eq(phi, 0), u > v + 1, n.is_positive is True, cstar.is_positive is True, bstar >= 0,
bstar*pi < Abs(unbranched_argument(sigma)),
Abs(unbranched_argument(sigma)) < (s + t - v + 1)*pi,
c1, c3, c12, c14, c15)] # 35
pr(35)
return Or(*conds)
# NOTE An alternative, but as far as I can tell weaker, set of conditions
# can be found in [L, section 5.6.2].
def _int0oo(g1, g2, x):
"""
Express integral from zero to infinity g1*g2 using a G function,
assuming the necessary conditions are fulfilled.
Examples
========
>>> from sympy.integrals.meijerint import _int0oo
>>> from sympy.abc import s, t, m
>>> from sympy import meijerg, S
>>> g1 = meijerg([], [], [-S(1)/2, 0], [], s**2*t/4)
>>> g2 = meijerg([], [], [m/2], [-m/2], t/4)
>>> _int0oo(g1, g2, t)
4*meijerg(((0, 1/2), ()), ((m/2,), (-m/2,)), s**(-2))/s**2
"""
# See: [L, section 5.6.2, equation (1)]
eta, _ = _get_coeff_exp(g1.argument, x)
omega, _ = _get_coeff_exp(g2.argument, x)
def neg(l):
return [-x for x in l]
a1 = neg(g1.bm) + list(g2.an)
a2 = list(g2.aother) + neg(g1.bother)
b1 = neg(g1.an) + list(g2.bm)
b2 = list(g2.bother) + neg(g1.aother)
return meijerg(a1, a2, b1, b2, omega/eta)/eta
def _rewrite_inversion(fac, po, g, x):
""" Absorb ``po`` == x**s into g. """
_, s = _get_coeff_exp(po, x)
a, b = _get_coeff_exp(g.argument, x)
def tr(l):
return [t + s/b for t in l]
from sympy.simplify import powdenest
return (powdenest(fac/a**(s/b), polar=True),
meijerg(tr(g.an), tr(g.aother), tr(g.bm), tr(g.bother), g.argument))
def _check_antecedents_inversion(g, x):
""" Check antecedents for the laplace inversion integral. """
_debug('Checking antecedents for inversion:')
z = g.argument
_, e = _get_coeff_exp(z, x)
if e < 0:
_debug(' Flipping G.')
# We want to assume that argument gets large as |x| -> oo
return _check_antecedents_inversion(_flip_g(g), x)
def statement_half(a, b, c, z, plus):
coeff, exponent = _get_coeff_exp(z, x)
a *= exponent
b *= coeff**c
c *= exponent
conds = []
wp = b*exp(S.ImaginaryUnit*re(c)*pi/2)
wm = b*exp(-S.ImaginaryUnit*re(c)*pi/2)
if plus:
w = wp
else:
w = wm
conds += [And(Or(Eq(b, 0), re(c) <= 0), re(a) <= -1)]
conds += [And(Ne(b, 0), Eq(im(c), 0), re(c) > 0, re(w) < 0)]
conds += [And(Ne(b, 0), Eq(im(c), 0), re(c) > 0, re(w) <= 0,
re(a) <= -1)]
return Or(*conds)
def statement(a, b, c, z):
""" Provide a convergence statement for z**a * exp(b*z**c),
c/f sphinx docs. """
return And(statement_half(a, b, c, z, True),
statement_half(a, b, c, z, False))
# Notations from [L], section 5.7-10
m, n, p, q = S([len(g.bm), len(g.an), len(g.ap), len(g.bq)])
tau = m + n - p
nu = q - m - n
rho = (tau - nu)/2
sigma = q - p
if sigma == 1:
epsilon = S.Half
elif sigma > 1:
epsilon = 1
else:
epsilon = S.NaN
theta = ((1 - sigma)/2 + Add(*g.bq) - Add(*g.ap))/sigma
delta = g.delta
_debugf(' m=%s, n=%s, p=%s, q=%s, tau=%s, nu=%s, rho=%s, sigma=%s',
(m, n, p, q, tau, nu, rho, sigma))
_debugf(' epsilon=%s, theta=%s, delta=%s', (epsilon, theta, delta))
# First check if the computation is valid.
if not (g.delta >= e/2 or (p >= 1 and p >= q)):
_debug(' Computation not valid for these parameters.')
return False
# Now check if the inversion integral exists.
# Test "condition A"
for a, b in itertools.product(g.an, g.bm):
if (a - b).is_integer and a > b:
_debug(' Not a valid G function.')
return False
# There are two cases. If p >= q, we can directly use a slater expansion
# like [L], 5.2 (11). Note in particular that the asymptotics of such an
# expansion even hold when some of the parameters differ by integers, i.e.
# the formula itself would not be valid! (b/c G functions are cts. in their
# parameters)
# When p < q, we need to use the theorems of [L], 5.10.
if p >= q:
_debug(' Using asymptotic Slater expansion.')
return And(*[statement(a - 1, 0, 0, z) for a in g.an])
def E(z):
return And(*[statement(a - 1, 0, 0, z) for a in g.an])
def H(z):
return statement(theta, -sigma, 1/sigma, z)
def Hp(z):
return statement_half(theta, -sigma, 1/sigma, z, True)
def Hm(z):
return statement_half(theta, -sigma, 1/sigma, z, False)
# [L], section 5.10
conds = []
# Theorem 1 -- p < q from test above
conds += [And(1 <= n, 1 <= m, rho*pi - delta >= pi/2, delta > 0,
E(z*exp(S.ImaginaryUnit*pi*(nu + 1))))]
# Theorem 2, statements (2) and (3)
conds += [And(p + 1 <= m, m + 1 <= q, delta > 0, delta < pi/2, n == 0,
(m - p + 1)*pi - delta >= pi/2,
Hp(z*exp(S.ImaginaryUnit*pi*(q - m))),
Hm(z*exp(-S.ImaginaryUnit*pi*(q - m))))]
# Theorem 2, statement (5) -- p < q from test above
conds += [And(m == q, n == 0, delta > 0,
(sigma + epsilon)*pi - delta >= pi/2, H(z))]
# Theorem 3, statements (6) and (7)
conds += [And(Or(And(p <= q - 2, 1 <= tau, tau <= sigma/2),
And(p + 1 <= m + n, m + n <= (p + q)/2)),
delta > 0, delta < pi/2, (tau + 1)*pi - delta >= pi/2,
Hp(z*exp(S.ImaginaryUnit*pi*nu)),
Hm(z*exp(-S.ImaginaryUnit*pi*nu)))]
# Theorem 4, statements (10) and (11) -- p < q from test above
conds += [And(1 <= m, rho > 0, delta > 0, delta + rho*pi < pi/2,
(tau + epsilon)*pi - delta >= pi/2,
Hp(z*exp(S.ImaginaryUnit*pi*nu)),
Hm(z*exp(-S.ImaginaryUnit*pi*nu)))]
# Trivial case
conds += [m == 0]
# TODO
# Theorem 5 is quite general
# Theorem 6 contains special cases for q=p+1
return Or(*conds)
def _int_inversion(g, x, t):
"""
Compute the laplace inversion integral, assuming the formula applies.
"""
b, a = _get_coeff_exp(g.argument, x)
C, g = _inflate_fox_h(meijerg(g.an, g.aother, g.bm, g.bother, b/t**a), -a)
return C/t*g
####################################################################
# Finally, the real meat.
####################################################################
_lookup_table = None
@cacheit
@timeit
def _rewrite_single(f, x, recursive=True):
"""
Try to rewrite f as a sum of single G functions of the form
C*x**s*G(a*x**b), where b is a rational number and C is independent of x.
We guarantee that result.argument.as_coeff_mul(x) returns (a, (x**b,))
or (a, ()).
Returns a list of tuples (C, s, G) and a condition cond.
Returns None on failure.
"""
from .transforms import (mellin_transform, inverse_mellin_transform,
IntegralTransformError, MellinTransformStripError)
global _lookup_table
if not _lookup_table:
_lookup_table = {}
_create_lookup_table(_lookup_table)
if isinstance(f, meijerg):
coeff, m = factor(f.argument, x).as_coeff_mul(x)
if len(m) > 1:
return None
m = m[0]
if m.is_Pow:
if m.base != x or not m.exp.is_Rational:
return None
elif m != x:
return None
return [(1, 0, meijerg(f.an, f.aother, f.bm, f.bother, coeff*m))], True
f_ = f
f = f.subs(x, z)
t = _mytype(f, z)
if t in _lookup_table:
l = _lookup_table[t]
for formula, terms, cond, hint in l:
subs = f.match(formula, old=True)
if subs:
subs_ = {}
for fro, to in subs.items():
subs_[fro] = unpolarify(polarify(to, lift=True),
exponents_only=True)
subs = subs_
if not isinstance(hint, bool):
hint = hint.subs(subs)
if hint == False:
continue
if not isinstance(cond, (bool, BooleanAtom)):
cond = unpolarify(cond.subs(subs))
if _eval_cond(cond) == False:
continue
if not isinstance(terms, list):
terms = terms(subs)
res = []
for fac, g in terms:
r1 = _get_coeff_exp(unpolarify(fac.subs(subs).subs(z, x),
exponents_only=True), x)
try:
g = g.subs(subs).subs(z, x)
except ValueError:
continue
# NOTE these substitutions can in principle introduce oo,
# zoo and other absurdities. It shouldn't matter,
# but better be safe.
if Tuple(*(r1 + (g,))).has(S.Infinity, S.ComplexInfinity, S.NegativeInfinity):
continue
g = meijerg(g.an, g.aother, g.bm, g.bother,
unpolarify(g.argument, exponents_only=True))
res.append(r1 + (g,))
if res:
return res, cond
# try recursive mellin transform
if not recursive:
return None
_debug('Trying recursive Mellin transform method.')
def my_imt(F, s, x, strip):
""" Calling simplify() all the time is slow and not helpful, since
most of the time it only factors things in a way that has to be
un-done anyway. But sometimes it can remove apparent poles. """
# XXX should this be in inverse_mellin_transform?
try:
return inverse_mellin_transform(F, s, x, strip,
as_meijerg=True, needeval=True)
except MellinTransformStripError:
from sympy.simplify import simplify
return inverse_mellin_transform(
simplify(cancel(expand(F))), s, x, strip,
as_meijerg=True, needeval=True)
f = f_
s = _dummy('s', 'rewrite-single', f)
# to avoid infinite recursion, we have to force the two g functions case
def my_integrator(f, x):
r = _meijerint_definite_4(f, x, only_double=True)
if r is not None:
from sympy.simplify import hyperexpand
res, cond = r
res = _my_unpolarify(hyperexpand(res, rewrite='nonrepsmall'))
return Piecewise((res, cond),
(Integral(f, (x, S.Zero, S.Infinity)), True))
return Integral(f, (x, S.Zero, S.Infinity))
try:
F, strip, _ = mellin_transform(f, x, s, integrator=my_integrator,
simplify=False, needeval=True)
g = my_imt(F, s, x, strip)
except IntegralTransformError:
g = None
if g is None:
# We try to find an expression by analytic continuation.
# (also if the dummy is already in the expression, there is no point in
# putting in another one)
a = _dummy_('a', 'rewrite-single')
if a not in f.free_symbols and _is_analytic(f, x):
try:
F, strip, _ = mellin_transform(f.subs(x, a*x), x, s,
integrator=my_integrator,
needeval=True, simplify=False)
g = my_imt(F, s, x, strip).subs(a, 1)
except IntegralTransformError:
g = None
if g is None or g.has(S.Infinity, S.NaN, S.ComplexInfinity):
_debug('Recursive Mellin transform failed.')
return None
args = Add.make_args(g)
res = []
for f in args:
c, m = f.as_coeff_mul(x)
if len(m) > 1:
raise NotImplementedError('Unexpected form...')
g = m[0]
a, b = _get_coeff_exp(g.argument, x)
res += [(c, 0, meijerg(g.an, g.aother, g.bm, g.bother,
unpolarify(polarify(
a, lift=True), exponents_only=True)
*x**b))]
_debug('Recursive Mellin transform worked:', g)
return res, True
def _rewrite1(f, x, recursive=True):
"""
Try to rewrite ``f`` using a (sum of) single G functions with argument a*x**b.
Return fac, po, g such that f = fac*po*g, fac is independent of ``x``.
and po = x**s.
Here g is a result from _rewrite_single.
Return None on failure.
"""
fac, po, g = _split_mul(f, x)
g = _rewrite_single(g, x, recursive)
if g:
return fac, po, g[0], g[1]
def _rewrite2(f, x):
"""
Try to rewrite ``f`` as a product of two G functions of arguments a*x**b.
Return fac, po, g1, g2 such that f = fac*po*g1*g2, where fac is
independent of x and po is x**s.
Here g1 and g2 are results of _rewrite_single.
Returns None on failure.
"""
fac, po, g = _split_mul(f, x)
if any(_rewrite_single(expr, x, False) is None for expr in _mul_args(g)):
return None
l = _mul_as_two_parts(g)
if not l:
return None
l = list(ordered(l, [
lambda p: max(len(_exponents(p[0], x)), len(_exponents(p[1], x))),
lambda p: max(len(_functions(p[0], x)), len(_functions(p[1], x))),
lambda p: max(len(_find_splitting_points(p[0], x)),
len(_find_splitting_points(p[1], x)))]))
for recursive, (fac1, fac2) in itertools.product((False, True), l):
g1 = _rewrite_single(fac1, x, recursive)
g2 = _rewrite_single(fac2, x, recursive)
if g1 and g2:
cond = And(g1[1], g2[1])
if cond != False:
return fac, po, g1[0], g2[0], cond
def meijerint_indefinite(f, x):
"""
Compute an indefinite integral of ``f`` by rewriting it as a G function.
Examples
========
>>> from sympy.integrals.meijerint import meijerint_indefinite
>>> from sympy import sin
>>> from sympy.abc import x
>>> meijerint_indefinite(sin(x), x)
-cos(x)
"""
f = sympify(f)
results = []
for a in sorted(_find_splitting_points(f, x) | {S.Zero}, key=default_sort_key):
res = _meijerint_indefinite_1(f.subs(x, x + a), x)
if not res:
continue
res = res.subs(x, x - a)
if _has(res, hyper, meijerg):
results.append(res)
else:
return res
if f.has(HyperbolicFunction):
_debug('Try rewriting hyperbolics in terms of exp.')
rv = meijerint_indefinite(
_rewrite_hyperbolics_as_exp(f), x)
if rv:
if not isinstance(rv, list):
from sympy.simplify.radsimp import collect
return collect(factor_terms(rv), rv.atoms(exp))
results.extend(rv)
if results:
return next(ordered(results))
def _meijerint_indefinite_1(f, x):
""" Helper that does not attempt any substitution. """
_debug('Trying to compute the indefinite integral of', f, 'wrt', x)
from sympy.simplify import hyperexpand, powdenest
gs = _rewrite1(f, x)
if gs is None:
# Note: the code that calls us will do expand() and try again
return None
fac, po, gl, cond = gs
_debug(' could rewrite:', gs)
res = S.Zero
for C, s, g in gl:
a, b = _get_coeff_exp(g.argument, x)
_, c = _get_coeff_exp(po, x)
c += s
# we do a substitution t=a*x**b, get integrand fac*t**rho*g
fac_ = fac * C * x**(1 + c) / b
rho = (c + 1)/b
# we now use t**rho*G(params, t) = G(params + rho, t)
# [L, page 150, equation (4)]
# and integral G(params, t) dt = G(1, params+1, 0, t)
# (or a similar expression with 1 and 0 exchanged ... pick the one
# which yields a well-defined function)
# [R, section 5]
# (Note that this dummy will immediately go away again, so we
# can safely pass S.One for ``expr``.)
t = _dummy('t', 'meijerint-indefinite', S.One)
def tr(p):
return [a + rho for a in p]
if any(b.is_integer and (b <= 0) == True for b in tr(g.bm)):
r = -meijerg(
list(g.an), list(g.aother) + [1-rho], list(g.bm) + [-rho], list(g.bother), t)
else:
r = meijerg(
list(g.an) + [1-rho], list(g.aother), list(g.bm), list(g.bother) + [-rho], t)
# The antiderivative is most often expected to be defined
# in the neighborhood of x = 0.
if b.is_extended_nonnegative and not f.subs(x, 0).has(S.NaN, S.ComplexInfinity):
place = 0 # Assume we can expand at zero
else:
place = None
r = hyperexpand(r.subs(t, a*x**b), place=place)
# now substitute back
# Note: we really do want the powers of x to combine.
res += powdenest(fac_*r, polar=True)
def _clean(res):
"""This multiplies out superfluous powers of x we created, and chops off
constants:
>> _clean(x*(exp(x)/x - 1/x) + 3)
exp(x)
cancel is used before mul_expand since it is possible for an
expression to have an additive constant that does not become isolated
with simple expansion. Such a situation was identified in issue 6369:
Examples
========
>>> from sympy import sqrt, cancel
>>> from sympy.abc import x
>>> a = sqrt(2*x + 1)
>>> bad = (3*x*a**5 + 2*x - a**5 + 1)/a**2
>>> bad.expand().as_independent(x)[0]
0
>>> cancel(bad).expand().as_independent(x)[0]
1
"""
res = expand_mul(cancel(res), deep=False)
return Add._from_args(res.as_coeff_add(x)[1])
res = piecewise_fold(res, evaluate=None)
if res.is_Piecewise:
newargs = []
for e, c in res.args:
e = _my_unpolarify(_clean(e))
newargs += [(e, c)]
res = Piecewise(*newargs, evaluate=False)
else:
res = _my_unpolarify(_clean(res))
return Piecewise((res, _my_unpolarify(cond)), (Integral(f, x), True))
@timeit
def meijerint_definite(f, x, a, b):
"""
Integrate ``f`` over the interval [``a``, ``b``], by rewriting it as a product
of two G functions, or as a single G function.
Return res, cond, where cond are convergence conditions.
Examples
========
>>> from sympy.integrals.meijerint import meijerint_definite
>>> from sympy import exp, oo
>>> from sympy.abc import x
>>> meijerint_definite(exp(-x**2), x, -oo, oo)
(sqrt(pi), True)
This function is implemented as a succession of functions
meijerint_definite, _meijerint_definite_2, _meijerint_definite_3,
_meijerint_definite_4. Each function in the list calls the next one
(presumably) several times. This means that calling meijerint_definite
can be very costly.
"""
# This consists of three steps:
# 1) Change the integration limits to 0, oo
# 2) Rewrite in terms of G functions
# 3) Evaluate the integral
#
# There are usually several ways of doing this, and we want to try all.
# This function does (1), calls _meijerint_definite_2 for step (2).
_debugf('Integrating %s wrt %s from %s to %s.', (f, x, a, b))
f = sympify(f)
if f.has(DiracDelta):
_debug('Integrand has DiracDelta terms - giving up.')
return None
if f.has(SingularityFunction):
_debug('Integrand has Singularity Function terms - giving up.')
return None
f_, x_, a_, b_ = f, x, a, b
# Let's use a dummy in case any of the boundaries has x.
d = Dummy('x')
f = f.subs(x, d)
x = d
if a == b:
return (S.Zero, True)
results = []
if a is S.NegativeInfinity and b is not S.Infinity:
return meijerint_definite(f.subs(x, -x), x, -b, -a)
elif a is S.NegativeInfinity:
# Integrating -oo to oo. We need to find a place to split the integral.
_debug(' Integrating -oo to +oo.')
innermost = _find_splitting_points(f, x)
_debug(' Sensible splitting points:', innermost)
for c in sorted(innermost, key=default_sort_key, reverse=True) + [S.Zero]:
_debug(' Trying to split at', c)
if not c.is_extended_real:
_debug(' Non-real splitting point.')
continue
res1 = _meijerint_definite_2(f.subs(x, x + c), x)
if res1 is None:
_debug(' But could not compute first integral.')
continue
res2 = _meijerint_definite_2(f.subs(x, c - x), x)
if res2 is None:
_debug(' But could not compute second integral.')
continue
res1, cond1 = res1
res2, cond2 = res2
cond = _condsimp(And(cond1, cond2))
if cond == False:
_debug(' But combined condition is always false.')
continue
res = res1 + res2
return res, cond
elif a is S.Infinity:
res = meijerint_definite(f, x, b, S.Infinity)
return -res[0], res[1]
elif (a, b) == (S.Zero, S.Infinity):
# This is a common case - try it directly first.
res = _meijerint_definite_2(f, x)
if res:
if _has(res[0], meijerg):
results.append(res)
else:
return res
else:
if b is S.Infinity:
for split in _find_splitting_points(f, x):
if (a - split >= 0) == True:
_debugf('Trying x -> x + %s', split)
res = _meijerint_definite_2(f.subs(x, x + split)
*Heaviside(x + split - a), x)
if res:
if _has(res[0], meijerg):
results.append(res)
else:
return res
f = f.subs(x, x + a)
b = b - a
a = 0
if b is not S.Infinity:
phi = exp(S.ImaginaryUnit*arg(b))
b = Abs(b)
f = f.subs(x, phi*x)
f *= Heaviside(b - x)*phi
b = S.Infinity
_debug('Changed limits to', a, b)
_debug('Changed function to', f)
res = _meijerint_definite_2(f, x)
if res:
if _has(res[0], meijerg):
results.append(res)
else:
return res
if f_.has(HyperbolicFunction):
_debug('Try rewriting hyperbolics in terms of exp.')
rv = meijerint_definite(
_rewrite_hyperbolics_as_exp(f_), x_, a_, b_)
if rv:
if not isinstance(rv, list):
from sympy.simplify.radsimp import collect
rv = (collect(factor_terms(rv[0]), rv[0].atoms(exp)),) + rv[1:]
return rv
results.extend(rv)
if results:
return next(ordered(results))
def _guess_expansion(f, x):
""" Try to guess sensible rewritings for integrand f(x). """
res = [(f, 'original integrand')]
orig = res[-1][0]
saw = {orig}
expanded = expand_mul(orig)
if expanded not in saw:
res += [(expanded, 'expand_mul')]
saw.add(expanded)
expanded = expand(orig)
if expanded not in saw:
res += [(expanded, 'expand')]
saw.add(expanded)
if orig.has(TrigonometricFunction, HyperbolicFunction):
expanded = expand_mul(expand_trig(orig))
if expanded not in saw:
res += [(expanded, 'expand_trig, expand_mul')]
saw.add(expanded)
if orig.has(cos, sin):
from sympy.simplify.fu import sincos_to_sum
reduced = sincos_to_sum(orig)
if reduced not in saw:
res += [(reduced, 'trig power reduction')]
saw.add(reduced)
return res
def _meijerint_definite_2(f, x):
"""
Try to integrate f dx from zero to infinity.
The body of this function computes various 'simplifications'
f1, f2, ... of f (e.g. by calling expand_mul(), trigexpand()
- see _guess_expansion) and calls _meijerint_definite_3 with each of
these in succession.
If _meijerint_definite_3 succeeds with any of the simplified functions,
returns this result.
"""
# This function does preparation for (2), calls
# _meijerint_definite_3 for (2) and (3) combined.
# use a positive dummy - we integrate from 0 to oo
# XXX if a nonnegative symbol is used there will be test failures
dummy = _dummy('x', 'meijerint-definite2', f, positive=True)
f = f.subs(x, dummy)
x = dummy
if f == 0:
return S.Zero, True
for g, explanation in _guess_expansion(f, x):
_debug('Trying', explanation)
res = _meijerint_definite_3(g, x)
if res:
return res
def _meijerint_definite_3(f, x):
"""
Try to integrate f dx from zero to infinity.
This function calls _meijerint_definite_4 to try to compute the
integral. If this fails, it tries using linearity.
"""
res = _meijerint_definite_4(f, x)
if res and res[1] != False:
return res
if f.is_Add:
_debug('Expanding and evaluating all terms.')
ress = [_meijerint_definite_4(g, x) for g in f.args]
if all(r is not None for r in ress):
conds = []
res = S.Zero
for r, c in ress:
res += r
conds += [c]
c = And(*conds)
if c != False:
return res, c
def _my_unpolarify(f):
return _eval_cond(unpolarify(f))
@timeit
def _meijerint_definite_4(f, x, only_double=False):
"""
Try to integrate f dx from zero to infinity.
Explanation
===========
This function tries to apply the integration theorems found in literature,
i.e. it tries to rewrite f as either one or a product of two G-functions.
The parameter ``only_double`` is used internally in the recursive algorithm
to disable trying to rewrite f as a single G-function.
"""
from sympy.simplify import hyperexpand
# This function does (2) and (3)
_debug('Integrating', f)
# Try single G function.
if not only_double:
gs = _rewrite1(f, x, recursive=False)
if gs is not None:
fac, po, g, cond = gs
_debug('Could rewrite as single G function:', fac, po, g)
res = S.Zero
for C, s, f in g:
if C == 0:
continue
C, f = _rewrite_saxena_1(fac*C, po*x**s, f, x)
res += C*_int0oo_1(f, x)
cond = And(cond, _check_antecedents_1(f, x))
if cond == False:
break
cond = _my_unpolarify(cond)
if cond == False:
_debug('But cond is always False.')
else:
_debug('Result before branch substitutions is:', res)
return _my_unpolarify(hyperexpand(res)), cond
# Try two G functions.
gs = _rewrite2(f, x)
if gs is not None:
for full_pb in [False, True]:
fac, po, g1, g2, cond = gs
_debug('Could rewrite as two G functions:', fac, po, g1, g2)
res = S.Zero
for C1, s1, f1 in g1:
for C2, s2, f2 in g2:
r = _rewrite_saxena(fac*C1*C2, po*x**(s1 + s2),
f1, f2, x, full_pb)
if r is None:
_debug('Non-rational exponents.')
return
C, f1_, f2_ = r
_debug('Saxena subst for yielded:', C, f1_, f2_)
cond = And(cond, _check_antecedents(f1_, f2_, x))
if cond == False:
break
res += C*_int0oo(f1_, f2_, x)
else:
continue
break
cond = _my_unpolarify(cond)
if cond == False:
_debugf('But cond is always False (full_pb=%s).', full_pb)
else:
_debugf('Result before branch substitutions is: %s', (res, ))
if only_double:
return res, cond
return _my_unpolarify(hyperexpand(res)), cond
def meijerint_inversion(f, x, t):
r"""
Compute the inverse laplace transform
$\int_{c+i\infty}^{c-i\infty} f(x) e^{tx}\, dx$,
for real c larger than the real part of all singularities of ``f``.
Note that ``t`` is always assumed real and positive.
Return None if the integral does not exist or could not be evaluated.
Examples
========
>>> from sympy.abc import x, t
>>> from sympy.integrals.meijerint import meijerint_inversion
>>> meijerint_inversion(1/x, x, t)
Heaviside(t)
"""
f_ = f
t_ = t
t = Dummy('t', polar=True) # We don't want sqrt(t**2) = abs(t) etc
f = f.subs(t_, t)
_debug('Laplace-inverting', f)
if not _is_analytic(f, x):
_debug('But expression is not analytic.')
return None
# Exponentials correspond to shifts; we filter them out and then
# shift the result later. If we are given an Add this will not
# work, but the calling code will take care of that.
shift = S.Zero
if f.is_Mul:
args = list(f.args)
elif isinstance(f, exp):
args = [f]
else:
args = None
if args:
newargs = []
exponentials = []
while args:
arg = args.pop()
if isinstance(arg, exp):
arg2 = expand(arg)
if arg2.is_Mul:
args += arg2.args
continue
try:
a, b = _get_coeff_exp(arg.args[0], x)
except _CoeffExpValueError:
b = 0
if b == 1:
exponentials.append(a)
else:
newargs.append(arg)
elif arg.is_Pow:
arg2 = expand(arg)
if arg2.is_Mul:
args += arg2.args
continue
if x not in arg.base.free_symbols:
try:
a, b = _get_coeff_exp(arg.exp, x)
except _CoeffExpValueError:
b = 0
if b == 1:
exponentials.append(a*log(arg.base))
newargs.append(arg)
else:
newargs.append(arg)
shift = Add(*exponentials)
f = Mul(*newargs)
if x not in f.free_symbols:
_debug('Expression consists of constant and exp shift:', f, shift)
cond = Eq(im(shift), 0)
if cond == False:
_debug('but shift is nonreal, cannot be a Laplace transform')
return None
res = f*DiracDelta(t + shift)
_debug('Result is a delta function, possibly conditional:', res, cond)
# cond is True or Eq
return Piecewise((res.subs(t, t_), cond))
gs = _rewrite1(f, x)
if gs is not None:
fac, po, g, cond = gs
_debug('Could rewrite as single G function:', fac, po, g)
res = S.Zero
for C, s, f in g:
C, f = _rewrite_inversion(fac*C, po*x**s, f, x)
res += C*_int_inversion(f, x, t)
cond = And(cond, _check_antecedents_inversion(f, x))
if cond == False:
break
cond = _my_unpolarify(cond)
if cond == False:
_debug('But cond is always False.')
else:
_debug('Result before branch substitution:', res)
from sympy.simplify import hyperexpand
res = _my_unpolarify(hyperexpand(res))
if not res.has(Heaviside):
res *= Heaviside(t)
res = res.subs(t, t + shift)
if not isinstance(cond, bool):
cond = cond.subs(t, t + shift)
from .transforms import InverseLaplaceTransform
return Piecewise((res.subs(t, t_), cond),
(InverseLaplaceTransform(f_.subs(t, t_), x, t_, None), True))
PK ]ZZZ��M� � sympy/integrals/meijerint_doc.py""" This module cooks up a docstring when imported. Its only purpose is to
be displayed in the sphinx documentation. """
from __future__ import annotations
from typing import Any
from sympy.integrals.meijerint import _create_lookup_table
from sympy.core.add import Add
from sympy.core.basic import Basic
from sympy.core.relational import Eq
from sympy.core.symbol import Symbol
from sympy.printing.latex import latex
t: dict[tuple[type[Basic], ...], list[Any]] = {}
_create_lookup_table(t)
doc = ""
for about, category in t.items():
if about == ():
doc += 'Elementary functions:\n\n'
else:
doc += 'Functions involving ' + ', '.join('`%s`' % latex(
list(category[0][0].atoms(func))[0]) for func in about) + ':\n\n'
for formula, gs, cond, hint in category:
if not isinstance(gs, list):
g = Symbol('\\text{generated}')
else:
g = Add(*[fac*f for (fac, f) in gs])
obj = Eq(formula, g)
if cond is True:
cond = ""
else:
cond = ',\\text{ if } %s' % latex(cond)
doc += ".. math::\n %s%s\n\n" % (latex(obj), cond)
__doc__ = doc
PK ]ZZZ�J��O� O� sympy/integrals/prde.py"""
Algorithms for solving Parametric Risch Differential Equations.
The methods used for solving Parametric Risch Differential Equations parallel
those for solving Risch Differential Equations. See the outline in the
docstring of rde.py for more information.
The Parametric Risch Differential Equation problem is, given f, g1, ..., gm in
K(t), to determine if there exist y in K(t) and c1, ..., cm in Const(K) such
that Dy + f*y == Sum(ci*gi, (i, 1, m)), and to find such y and ci if they exist.
For the algorithms here G is a list of tuples of factions of the terms on the
right hand side of the equation (i.e., gi in k(t)), and Q is a list of terms on
the right hand side of the equation (i.e., qi in k[t]). See the docstring of
each function for more information.
"""
import itertools
from functools import reduce
from sympy.core.intfunc import ilcm
from sympy.core import Dummy, Add, Mul, Pow, S
from sympy.integrals.rde import (order_at, order_at_oo, weak_normalizer,
bound_degree)
from sympy.integrals.risch import (gcdex_diophantine, frac_in, derivation,
residue_reduce, splitfactor, residue_reduce_derivation, DecrementLevel,
recognize_log_derivative)
from sympy.polys import Poly, lcm, cancel, sqf_list
from sympy.polys.polymatrix import PolyMatrix as Matrix
from sympy.solvers import solve
zeros = Matrix.zeros
eye = Matrix.eye
def prde_normal_denom(fa, fd, G, DE):
"""
Parametric Risch Differential Equation - Normal part of the denominator.
Explanation
===========
Given a derivation D on k[t] and f, g1, ..., gm in k(t) with f weakly
normalized with respect to t, return the tuple (a, b, G, h) such that
a, h in k[t], b in k<t>, G = [g1, ..., gm] in k(t)^m, and for any solution
c1, ..., cm in Const(k) and y in k(t) of Dy + f*y == Sum(ci*gi, (i, 1, m)),
q == y*h in k<t> satisfies a*Dq + b*q == Sum(ci*Gi, (i, 1, m)).
"""
dn, ds = splitfactor(fd, DE)
Gas, Gds = list(zip(*G))
gd = reduce(lambda i, j: i.lcm(j), Gds, Poly(1, DE.t))
en, es = splitfactor(gd, DE)
p = dn.gcd(en)
h = en.gcd(en.diff(DE.t)).quo(p.gcd(p.diff(DE.t)))
a = dn*h
c = a*h
ba = a*fa - dn*derivation(h, DE)*fd
ba, bd = ba.cancel(fd, include=True)
G = [(c*A).cancel(D, include=True) for A, D in G]
return (a, (ba, bd), G, h)
def real_imag(ba, bd, gen):
"""
Helper function, to get the real and imaginary part of a rational function
evaluated at sqrt(-1) without actually evaluating it at sqrt(-1).
Explanation
===========
Separates the even and odd power terms by checking the degree of terms wrt
mod 4. Returns a tuple (ba[0], ba[1], bd) where ba[0] is real part
of the numerator ba[1] is the imaginary part and bd is the denominator
of the rational function.
"""
bd = bd.as_poly(gen).as_dict()
ba = ba.as_poly(gen).as_dict()
denom_real = [value if key[0] % 4 == 0 else -value if key[0] % 4 == 2 else 0 for key, value in bd.items()]
denom_imag = [value if key[0] % 4 == 1 else -value if key[0] % 4 == 3 else 0 for key, value in bd.items()]
bd_real = sum(r for r in denom_real)
bd_imag = sum(r for r in denom_imag)
num_real = [value if key[0] % 4 == 0 else -value if key[0] % 4 == 2 else 0 for key, value in ba.items()]
num_imag = [value if key[0] % 4 == 1 else -value if key[0] % 4 == 3 else 0 for key, value in ba.items()]
ba_real = sum(r for r in num_real)
ba_imag = sum(r for r in num_imag)
ba = ((ba_real*bd_real + ba_imag*bd_imag).as_poly(gen), (ba_imag*bd_real - ba_real*bd_imag).as_poly(gen))
bd = (bd_real*bd_real + bd_imag*bd_imag).as_poly(gen)
return (ba[0], ba[1], bd)
def prde_special_denom(a, ba, bd, G, DE, case='auto'):
"""
Parametric Risch Differential Equation - Special part of the denominator.
Explanation
===========
Case is one of {'exp', 'tan', 'primitive'} for the hyperexponential,
hypertangent, and primitive cases, respectively. For the hyperexponential
(resp. hypertangent) case, given a derivation D on k[t] and a in k[t],
b in k<t>, and g1, ..., gm in k(t) with Dt/t in k (resp. Dt/(t**2 + 1) in
k, sqrt(-1) not in k), a != 0, and gcd(a, t) == 1 (resp.
gcd(a, t**2 + 1) == 1), return the tuple (A, B, GG, h) such that A, B, h in
k[t], GG = [gg1, ..., ggm] in k(t)^m, and for any solution c1, ..., cm in
Const(k) and q in k<t> of a*Dq + b*q == Sum(ci*gi, (i, 1, m)), r == q*h in
k[t] satisfies A*Dr + B*r == Sum(ci*ggi, (i, 1, m)).
For case == 'primitive', k<t> == k[t], so it returns (a, b, G, 1) in this
case.
"""
# TODO: Merge this with the very similar special_denom() in rde.py
if case == 'auto':
case = DE.case
if case == 'exp':
p = Poly(DE.t, DE.t)
elif case == 'tan':
p = Poly(DE.t**2 + 1, DE.t)
elif case in ('primitive', 'base'):
B = ba.quo(bd)
return (a, B, G, Poly(1, DE.t))
else:
raise ValueError("case must be one of {'exp', 'tan', 'primitive', "
"'base'}, not %s." % case)
nb = order_at(ba, p, DE.t) - order_at(bd, p, DE.t)
nc = min(order_at(Ga, p, DE.t) - order_at(Gd, p, DE.t) for Ga, Gd in G)
n = min(0, nc - min(0, nb))
if not nb:
# Possible cancellation.
if case == 'exp':
dcoeff = DE.d.quo(Poly(DE.t, DE.t))
with DecrementLevel(DE): # We are guaranteed to not have problems,
# because case != 'base'.
alphaa, alphad = frac_in(-ba.eval(0)/bd.eval(0)/a.eval(0), DE.t)
etaa, etad = frac_in(dcoeff, DE.t)
A = parametric_log_deriv(alphaa, alphad, etaa, etad, DE)
if A is not None:
Q, m, z = A
if Q == 1:
n = min(n, m)
elif case == 'tan':
dcoeff = DE.d.quo(Poly(DE.t**2 + 1, DE.t))
with DecrementLevel(DE): # We are guaranteed to not have problems,
# because case != 'base'.
betaa, alphaa, alphad = real_imag(ba, bd*a, DE.t)
betad = alphad
etaa, etad = frac_in(dcoeff, DE.t)
if recognize_log_derivative(Poly(2, DE.t)*betaa, betad, DE):
A = parametric_log_deriv(alphaa, alphad, etaa, etad, DE)
B = parametric_log_deriv(betaa, betad, etaa, etad, DE)
if A is not None and B is not None:
Q, s, z = A
# TODO: Add test
if Q == 1:
n = min(n, s/2)
N = max(0, -nb)
pN = p**N
pn = p**-n # This is 1/h
A = a*pN
B = ba*pN.quo(bd) + Poly(n, DE.t)*a*derivation(p, DE).quo(p)*pN
G = [(Ga*pN*pn).cancel(Gd, include=True) for Ga, Gd in G]
h = pn
# (a*p**N, (b + n*a*Dp/p)*p**N, g1*p**(N - n), ..., gm*p**(N - n), p**-n)
return (A, B, G, h)
def prde_linear_constraints(a, b, G, DE):
"""
Parametric Risch Differential Equation - Generate linear constraints on the constants.
Explanation
===========
Given a derivation D on k[t], a, b, in k[t] with gcd(a, b) == 1, and
G = [g1, ..., gm] in k(t)^m, return Q = [q1, ..., qm] in k[t]^m and a
matrix M with entries in k(t) such that for any solution c1, ..., cm in
Const(k) and p in k[t] of a*Dp + b*p == Sum(ci*gi, (i, 1, m)),
(c1, ..., cm) is a solution of Mx == 0, and p and the ci satisfy
a*Dp + b*p == Sum(ci*qi, (i, 1, m)).
Because M has entries in k(t), and because Matrix does not play well with
Poly, M will be a Matrix of Basic expressions.
"""
m = len(G)
Gns, Gds = list(zip(*G))
d = reduce(lambda i, j: i.lcm(j), Gds)
d = Poly(d, field=True)
Q = [(ga*(d).quo(gd)).div(d) for ga, gd in G]
if not all(ri.is_zero for _, ri in Q):
N = max(ri.degree(DE.t) for _, ri in Q)
M = Matrix(N + 1, m, lambda i, j: Q[j][1].nth(i), DE.t)
else:
M = Matrix(0, m, [], DE.t) # No constraints, return the empty matrix.
qs, _ = list(zip(*Q))
return (qs, M)
def poly_linear_constraints(p, d):
"""
Given p = [p1, ..., pm] in k[t]^m and d in k[t], return
q = [q1, ..., qm] in k[t]^m and a matrix M with entries in k such
that Sum(ci*pi, (i, 1, m)), for c1, ..., cm in k, is divisible
by d if and only if (c1, ..., cm) is a solution of Mx = 0, in
which case the quotient is Sum(ci*qi, (i, 1, m)).
"""
m = len(p)
q, r = zip(*[pi.div(d) for pi in p])
if not all(ri.is_zero for ri in r):
n = max(ri.degree() for ri in r)
M = Matrix(n + 1, m, lambda i, j: r[j].nth(i), d.gens)
else:
M = Matrix(0, m, [], d.gens) # No constraints.
return q, M
def constant_system(A, u, DE):
"""
Generate a system for the constant solutions.
Explanation
===========
Given a differential field (K, D) with constant field C = Const(K), a Matrix
A, and a vector (Matrix) u with coefficients in K, returns the tuple
(B, v, s), where B is a Matrix with coefficients in C and v is a vector
(Matrix) such that either v has coefficients in C, in which case s is True
and the solutions in C of Ax == u are exactly all the solutions of Bx == v,
or v has a non-constant coefficient, in which case s is False Ax == u has no
constant solution.
This algorithm is used both in solving parametric problems and in
determining if an element a of K is a derivative of an element of K or the
logarithmic derivative of a K-radical using the structure theorem approach.
Because Poly does not play well with Matrix yet, this algorithm assumes that
all matrix entries are Basic expressions.
"""
if not A:
return A, u
Au = A.row_join(u)
Au, _ = Au.rref()
# Warning: This will NOT return correct results if cancel() cannot reduce
# an identically zero expression to 0. The danger is that we might
# incorrectly prove that an integral is nonelementary (such as
# risch_integrate(exp((sin(x)**2 + cos(x)**2 - 1)*x**2), x).
# But this is a limitation in computer algebra in general, and implicit
# in the correctness of the Risch Algorithm is the computability of the
# constant field (actually, this same correctness problem exists in any
# algorithm that uses rref()).
#
# We therefore limit ourselves to constant fields that are computable
# via the cancel() function, in order to prevent a speed bottleneck from
# calling some more complex simplification function (rational function
# coefficients will fall into this class). Furthermore, (I believe) this
# problem will only crop up if the integral explicitly contains an
# expression in the constant field that is identically zero, but cannot
# be reduced to such by cancel(). Therefore, a careful user can avoid this
# problem entirely by being careful with the sorts of expressions that
# appear in his integrand in the variables other than the integration
# variable (the structure theorems should be able to completely decide these
# problems in the integration variable).
A, u = Au[:, :-1], Au[:, -1]
D = lambda x: derivation(x, DE, basic=True)
for j, i in itertools.product(range(A.cols), range(A.rows)):
if A[i, j].expr.has(*DE.T):
# This assumes that const(F(t0, ..., tn) == const(K) == F
Ri = A[i, :]
# Rm+1; m = A.rows
DAij = D(A[i, j])
Rm1 = Ri.applyfunc(lambda x: D(x) / DAij)
um1 = D(u[i]) / DAij
Aj = A[:, j]
A = A - Aj * Rm1
u = u - Aj * um1
A = A.col_join(Rm1)
u = u.col_join(Matrix([um1], u.gens))
return (A, u)
def prde_spde(a, b, Q, n, DE):
"""
Special Polynomial Differential Equation algorithm: Parametric Version.
Explanation
===========
Given a derivation D on k[t], an integer n, and a, b, q1, ..., qm in k[t]
with deg(a) > 0 and gcd(a, b) == 1, return (A, B, Q, R, n1), with
Qq = [q1, ..., qm] and R = [r1, ..., rm], such that for any solution
c1, ..., cm in Const(k) and q in k[t] of degree at most n of
a*Dq + b*q == Sum(ci*gi, (i, 1, m)), p = (q - Sum(ci*ri, (i, 1, m)))/a has
degree at most n1 and satisfies A*Dp + B*p == Sum(ci*qi, (i, 1, m))
"""
R, Z = list(zip(*[gcdex_diophantine(b, a, qi) for qi in Q]))
A = a
B = b + derivation(a, DE)
Qq = [zi - derivation(ri, DE) for ri, zi in zip(R, Z)]
R = list(R)
n1 = n - a.degree(DE.t)
return (A, B, Qq, R, n1)
def prde_no_cancel_b_large(b, Q, n, DE):
"""
Parametric Poly Risch Differential Equation - No cancellation: deg(b) large enough.
Explanation
===========
Given a derivation D on k[t], n in ZZ, and b, q1, ..., qm in k[t] with
b != 0 and either D == d/dt or deg(b) > max(0, deg(D) - 1), returns
h1, ..., hr in k[t] and a matrix A with coefficients in Const(k) such that
if c1, ..., cm in Const(k) and q in k[t] satisfy deg(q) <= n and
Dq + b*q == Sum(ci*qi, (i, 1, m)), then q = Sum(dj*hj, (j, 1, r)), where
d1, ..., dr in Const(k) and A*Matrix([[c1, ..., cm, d1, ..., dr]]).T == 0.
"""
db = b.degree(DE.t)
m = len(Q)
H = [Poly(0, DE.t)]*m
for N, i in itertools.product(range(n, -1, -1), range(m)): # [n, ..., 0]
si = Q[i].nth(N + db)/b.LC()
sitn = Poly(si*DE.t**N, DE.t)
H[i] = H[i] + sitn
Q[i] = Q[i] - derivation(sitn, DE) - b*sitn
if all(qi.is_zero for qi in Q):
dc = -1
else:
dc = max(qi.degree(DE.t) for qi in Q)
M = Matrix(dc + 1, m, lambda i, j: Q[j].nth(i), DE.t)
A, u = constant_system(M, zeros(dc + 1, 1, DE.t), DE)
c = eye(m, DE.t)
A = A.row_join(zeros(A.rows, m, DE.t)).col_join(c.row_join(-c))
return (H, A)
def prde_no_cancel_b_small(b, Q, n, DE):
"""
Parametric Poly Risch Differential Equation - No cancellation: deg(b) small enough.
Explanation
===========
Given a derivation D on k[t], n in ZZ, and b, q1, ..., qm in k[t] with
deg(b) < deg(D) - 1 and either D == d/dt or deg(D) >= 2, returns
h1, ..., hr in k[t] and a matrix A with coefficients in Const(k) such that
if c1, ..., cm in Const(k) and q in k[t] satisfy deg(q) <= n and
Dq + b*q == Sum(ci*qi, (i, 1, m)) then q = Sum(dj*hj, (j, 1, r)) where
d1, ..., dr in Const(k) and A*Matrix([[c1, ..., cm, d1, ..., dr]]).T == 0.
"""
m = len(Q)
H = [Poly(0, DE.t)]*m
for N, i in itertools.product(range(n, 0, -1), range(m)): # [n, ..., 1]
si = Q[i].nth(N + DE.d.degree(DE.t) - 1)/(N*DE.d.LC())
sitn = Poly(si*DE.t**N, DE.t)
H[i] = H[i] + sitn
Q[i] = Q[i] - derivation(sitn, DE) - b*sitn
if b.degree(DE.t) > 0:
for i in range(m):
si = Poly(Q[i].nth(b.degree(DE.t))/b.LC(), DE.t)
H[i] = H[i] + si
Q[i] = Q[i] - derivation(si, DE) - b*si
if all(qi.is_zero for qi in Q):
dc = -1
else:
dc = max(qi.degree(DE.t) for qi in Q)
M = Matrix(dc + 1, m, lambda i, j: Q[j].nth(i), DE.t)
A, u = constant_system(M, zeros(dc + 1, 1, DE.t), DE)
c = eye(m, DE.t)
A = A.row_join(zeros(A.rows, m, DE.t)).col_join(c.row_join(-c))
return (H, A)
# else: b is in k, deg(qi) < deg(Dt)
t = DE.t
if DE.case != 'base':
with DecrementLevel(DE):
t0 = DE.t # k = k0(t0)
ba, bd = frac_in(b, t0, field=True)
Q0 = [frac_in(qi.TC(), t0, field=True) for qi in Q]
f, B = param_rischDE(ba, bd, Q0, DE)
# f = [f1, ..., fr] in k^r and B is a matrix with
# m + r columns and entries in Const(k) = Const(k0)
# such that Dy0 + b*y0 = Sum(ci*qi, (i, 1, m)) has
# a solution y0 in k with c1, ..., cm in Const(k)
# if and only y0 = Sum(dj*fj, (j, 1, r)) where
# d1, ..., dr ar in Const(k) and
# B*Matrix([c1, ..., cm, d1, ..., dr]) == 0.
# Transform fractions (fa, fd) in f into constant
# polynomials fa/fd in k[t].
# (Is there a better way?)
f = [Poly(fa.as_expr()/fd.as_expr(), t, field=True)
for fa, fd in f]
B = Matrix.from_Matrix(B.to_Matrix(), t)
else:
# Base case. Dy == 0 for all y in k and b == 0.
# Dy + b*y = Sum(ci*qi) is solvable if and only if
# Sum(ci*qi) == 0 in which case the solutions are
# y = d1*f1 for f1 = 1 and any d1 in Const(k) = k.
f = [Poly(1, t, field=True)] # r = 1
B = Matrix([[qi.TC() for qi in Q] + [S.Zero]], DE.t)
# The condition for solvability is
# B*Matrix([c1, ..., cm, d1]) == 0
# There are no constraints on d1.
# Coefficients of t^j (j > 0) in Sum(ci*qi) must be zero.
d = max(qi.degree(DE.t) for qi in Q)
if d > 0:
M = Matrix(d, m, lambda i, j: Q[j].nth(i + 1), DE.t)
A, _ = constant_system(M, zeros(d, 1, DE.t), DE)
else:
# No constraints on the hj.
A = Matrix(0, m, [], DE.t)
# Solutions of the original equation are
# y = Sum(dj*fj, (j, 1, r) + Sum(ei*hi, (i, 1, m)),
# where ei == ci (i = 1, ..., m), when
# A*Matrix([c1, ..., cm]) == 0 and
# B*Matrix([c1, ..., cm, d1, ..., dr]) == 0
# Build combined constraint matrix with m + r + m columns.
r = len(f)
I = eye(m, DE.t)
A = A.row_join(zeros(A.rows, r + m, DE.t))
B = B.row_join(zeros(B.rows, m, DE.t))
C = I.row_join(zeros(m, r, DE.t)).row_join(-I)
return f + H, A.col_join(B).col_join(C)
def prde_cancel_liouvillian(b, Q, n, DE):
"""
Pg, 237.
"""
H = []
# Why use DecrementLevel? Below line answers that:
# Assuming that we can solve such problems over 'k' (not k[t])
if DE.case == 'primitive':
with DecrementLevel(DE):
ba, bd = frac_in(b, DE.t, field=True)
for i in range(n, -1, -1):
if DE.case == 'exp': # this re-checking can be avoided
with DecrementLevel(DE):
ba, bd = frac_in(b + (i*(derivation(DE.t, DE)/DE.t)).as_poly(b.gens),
DE.t, field=True)
with DecrementLevel(DE):
Qy = [frac_in(q.nth(i), DE.t, field=True) for q in Q]
fi, Ai = param_rischDE(ba, bd, Qy, DE)
fi = [Poly(fa.as_expr()/fd.as_expr(), DE.t, field=True)
for fa, fd in fi]
Ai = Ai.set_gens(DE.t)
ri = len(fi)
if i == n:
M = Ai
else:
M = Ai.col_join(M.row_join(zeros(M.rows, ri, DE.t)))
Fi, hi = [None]*ri, [None]*ri
# from eq. on top of p.238 (unnumbered)
for j in range(ri):
hji = fi[j] * (DE.t**i).as_poly(fi[j].gens)
hi[j] = hji
# building up Sum(djn*(D(fjn*t^n) - b*fjnt^n))
Fi[j] = -(derivation(hji, DE) - b*hji)
H += hi
# in the next loop instead of Q it has
# to be Q + Fi taking its place
Q = Q + Fi
return (H, M)
def param_poly_rischDE(a, b, q, n, DE):
"""Polynomial solutions of a parametric Risch differential equation.
Explanation
===========
Given a derivation D in k[t], a, b in k[t] relatively prime, and q
= [q1, ..., qm] in k[t]^m, return h = [h1, ..., hr] in k[t]^r and
a matrix A with m + r columns and entries in Const(k) such that
a*Dp + b*p = Sum(ci*qi, (i, 1, m)) has a solution p of degree <= n
in k[t] with c1, ..., cm in Const(k) if and only if p = Sum(dj*hj,
(j, 1, r)) where d1, ..., dr are in Const(k) and (c1, ..., cm,
d1, ..., dr) is a solution of Ax == 0.
"""
m = len(q)
if n < 0:
# Only the trivial zero solution is possible.
# Find relations between the qi.
if all(qi.is_zero for qi in q):
return [], zeros(1, m, DE.t) # No constraints.
N = max(qi.degree(DE.t) for qi in q)
M = Matrix(N + 1, m, lambda i, j: q[j].nth(i), DE.t)
A, _ = constant_system(M, zeros(M.rows, 1, DE.t), DE)
return [], A
if a.is_ground:
# Normalization: a = 1.
a = a.LC()
b, q = b.quo_ground(a), [qi.quo_ground(a) for qi in q]
if not b.is_zero and (DE.case == 'base' or
b.degree() > max(0, DE.d.degree() - 1)):
return prde_no_cancel_b_large(b, q, n, DE)
elif ((b.is_zero or b.degree() < DE.d.degree() - 1)
and (DE.case == 'base' or DE.d.degree() >= 2)):
return prde_no_cancel_b_small(b, q, n, DE)
elif (DE.d.degree() >= 2 and
b.degree() == DE.d.degree() - 1 and
n > -b.as_poly().LC()/DE.d.as_poly().LC()):
raise NotImplementedError("prde_no_cancel_b_equal() is "
"not yet implemented.")
else:
# Liouvillian cases
if DE.case in ('primitive', 'exp'):
return prde_cancel_liouvillian(b, q, n, DE)
else:
raise NotImplementedError("non-linear and hypertangent "
"cases have not yet been implemented")
# else: deg(a) > 0
# Iterate SPDE as long as possible cumulating coefficient
# and terms for the recovery of original solutions.
alpha, beta = a.one, [a.zero]*m
while n >= 0: # and a, b relatively prime
a, b, q, r, n = prde_spde(a, b, q, n, DE)
beta = [betai + alpha*ri for betai, ri in zip(beta, r)]
alpha *= a
# Solutions p of a*Dp + b*p = Sum(ci*qi) correspond to
# solutions alpha*p + Sum(ci*betai) of the initial equation.
d = a.gcd(b)
if not d.is_ground:
break
# a*Dp + b*p = Sum(ci*qi) may have a polynomial solution
# only if the sum is divisible by d.
qq, M = poly_linear_constraints(q, d)
# qq = [qq1, ..., qqm] where qqi = qi.quo(d).
# M is a matrix with m columns an entries in k.
# Sum(fi*qi, (i, 1, m)), where f1, ..., fm are elements of k, is
# divisible by d if and only if M*Matrix([f1, ..., fm]) == 0,
# in which case the quotient is Sum(fi*qqi).
A, _ = constant_system(M, zeros(M.rows, 1, DE.t), DE)
# A is a matrix with m columns and entries in Const(k).
# Sum(ci*qqi) is Sum(ci*qi).quo(d), and the remainder is zero
# for c1, ..., cm in Const(k) if and only if
# A*Matrix([c1, ...,cm]) == 0.
V = A.nullspace()
# V = [v1, ..., vu] where each vj is a column matrix with
# entries aj1, ..., ajm in Const(k).
# Sum(aji*qi) is divisible by d with exact quotient Sum(aji*qqi).
# Sum(ci*qi) is divisible by d if and only if ci = Sum(dj*aji)
# (i = 1, ..., m) for some d1, ..., du in Const(k).
# In that case, solutions of
# a*Dp + b*p = Sum(ci*qi) = Sum(dj*Sum(aji*qi))
# are the same as those of
# (a/d)*Dp + (b/d)*p = Sum(dj*rj)
# where rj = Sum(aji*qqi).
if not V: # No non-trivial solution.
return [], eye(m, DE.t) # Could return A, but this has
# the minimum number of rows.
Mqq = Matrix([qq]) # A single row.
r = [(Mqq*vj)[0] for vj in V] # [r1, ..., ru]
# Solutions of (a/d)*Dp + (b/d)*p = Sum(dj*rj) correspond to
# solutions alpha*p + Sum(Sum(dj*aji)*betai) of the initial
# equation. These are equal to alpha*p + Sum(dj*fj) where
# fj = Sum(aji*betai).
Mbeta = Matrix([beta])
f = [(Mbeta*vj)[0] for vj in V] # [f1, ..., fu]
#
# Solve the reduced equation recursively.
#
g, B = param_poly_rischDE(a.quo(d), b.quo(d), r, n, DE)
# g = [g1, ..., gv] in k[t]^v and and B is a matrix with u + v
# columns and entries in Const(k) such that
# (a/d)*Dp + (b/d)*p = Sum(dj*rj) has a solution p of degree <= n
# in k[t] if and only if p = Sum(ek*gk) where e1, ..., ev are in
# Const(k) and B*Matrix([d1, ..., du, e1, ..., ev]) == 0.
# The solutions of the original equation are then
# Sum(dj*fj, (j, 1, u)) + alpha*Sum(ek*gk, (k, 1, v)).
# Collect solution components.
h = f + [alpha*gk for gk in g]
# Build combined relation matrix.
A = -eye(m, DE.t)
for vj in V:
A = A.row_join(vj)
A = A.row_join(zeros(m, len(g), DE.t))
A = A.col_join(zeros(B.rows, m, DE.t).row_join(B))
return h, A
def param_rischDE(fa, fd, G, DE):
"""
Solve a Parametric Risch Differential Equation: Dy + f*y == Sum(ci*Gi, (i, 1, m)).
Explanation
===========
Given a derivation D in k(t), f in k(t), and G
= [G1, ..., Gm] in k(t)^m, return h = [h1, ..., hr] in k(t)^r and
a matrix A with m + r columns and entries in Const(k) such that
Dy + f*y = Sum(ci*Gi, (i, 1, m)) has a solution y
in k(t) with c1, ..., cm in Const(k) if and only if y = Sum(dj*hj,
(j, 1, r)) where d1, ..., dr are in Const(k) and (c1, ..., cm,
d1, ..., dr) is a solution of Ax == 0.
Elements of k(t) are tuples (a, d) with a and d in k[t].
"""
m = len(G)
q, (fa, fd) = weak_normalizer(fa, fd, DE)
# Solutions of the weakly normalized equation Dz + f*z = q*Sum(ci*Gi)
# correspond to solutions y = z/q of the original equation.
gamma = q
G = [(q*ga).cancel(gd, include=True) for ga, gd in G]
a, (ba, bd), G, hn = prde_normal_denom(fa, fd, G, DE)
# Solutions q in k<t> of a*Dq + b*q = Sum(ci*Gi) correspond
# to solutions z = q/hn of the weakly normalized equation.
gamma *= hn
A, B, G, hs = prde_special_denom(a, ba, bd, G, DE)
# Solutions p in k[t] of A*Dp + B*p = Sum(ci*Gi) correspond
# to solutions q = p/hs of the previous equation.
gamma *= hs
g = A.gcd(B)
a, b, g = A.quo(g), B.quo(g), [gia.cancel(gid*g, include=True) for
gia, gid in G]
# a*Dp + b*p = Sum(ci*gi) may have a polynomial solution
# only if the sum is in k[t].
q, M = prde_linear_constraints(a, b, g, DE)
# q = [q1, ..., qm] where qi in k[t] is the polynomial component
# of the partial fraction expansion of gi.
# M is a matrix with m columns and entries in k.
# Sum(fi*gi, (i, 1, m)), where f1, ..., fm are elements of k,
# is a polynomial if and only if M*Matrix([f1, ..., fm]) == 0,
# in which case the sum is equal to Sum(fi*qi).
M, _ = constant_system(M, zeros(M.rows, 1, DE.t), DE)
# M is a matrix with m columns and entries in Const(k).
# Sum(ci*gi) is in k[t] for c1, ..., cm in Const(k)
# if and only if M*Matrix([c1, ..., cm]) == 0,
# in which case the sum is Sum(ci*qi).
## Reduce number of constants at this point
V = M.nullspace()
# V = [v1, ..., vu] where each vj is a column matrix with
# entries aj1, ..., ajm in Const(k).
# Sum(aji*gi) is in k[t] and equal to Sum(aji*qi) (j = 1, ..., u).
# Sum(ci*gi) is in k[t] if and only is ci = Sum(dj*aji)
# (i = 1, ..., m) for some d1, ..., du in Const(k).
# In that case,
# Sum(ci*gi) = Sum(ci*qi) = Sum(dj*Sum(aji*qi)) = Sum(dj*rj)
# where rj = Sum(aji*qi) (j = 1, ..., u) in k[t].
if not V: # No non-trivial solution
return [], eye(m, DE.t)
Mq = Matrix([q]) # A single row.
r = [(Mq*vj)[0] for vj in V] # [r1, ..., ru]
# Solutions of a*Dp + b*p = Sum(dj*rj) correspond to solutions
# y = p/gamma of the initial equation with ci = Sum(dj*aji).
try:
# We try n=5. At least for prde_spde, it will always
# terminate no matter what n is.
n = bound_degree(a, b, r, DE, parametric=True)
except NotImplementedError:
# A temporary bound is set. Eventually, it will be removed.
# the currently added test case takes large time
# even with n=5, and much longer with large n's.
n = 5
h, B = param_poly_rischDE(a, b, r, n, DE)
# h = [h1, ..., hv] in k[t]^v and and B is a matrix with u + v
# columns and entries in Const(k) such that
# a*Dp + b*p = Sum(dj*rj) has a solution p of degree <= n
# in k[t] if and only if p = Sum(ek*hk) where e1, ..., ev are in
# Const(k) and B*Matrix([d1, ..., du, e1, ..., ev]) == 0.
# The solutions of the original equation for ci = Sum(dj*aji)
# (i = 1, ..., m) are then y = Sum(ek*hk, (k, 1, v))/gamma.
## Build combined relation matrix with m + u + v columns.
A = -eye(m, DE.t)
for vj in V:
A = A.row_join(vj)
A = A.row_join(zeros(m, len(h), DE.t))
A = A.col_join(zeros(B.rows, m, DE.t).row_join(B))
## Eliminate d1, ..., du.
W = A.nullspace()
# W = [w1, ..., wt] where each wl is a column matrix with
# entries blk (k = 1, ..., m + u + v) in Const(k).
# The vectors (bl1, ..., blm) generate the space of those
# constant families (c1, ..., cm) for which a solution of
# the equation Dy + f*y == Sum(ci*Gi) exists. They generate
# the space and form a basis except possibly when Dy + f*y == 0
# is solvable in k(t}. The corresponding solutions are
# y = Sum(blk'*hk, (k, 1, v))/gamma, where k' = k + m + u.
v = len(h)
shape = (len(W), m+v)
elements = [wl[:m] + wl[-v:] for wl in W] # excise dj's.
items = [e for row in elements for e in row]
# Need to set the shape in case W is empty
M = Matrix(*shape, items, DE.t)
N = M.nullspace()
# N = [n1, ..., ns] where the ni in Const(k)^(m + v) are column
# vectors generating the space of linear relations between
# c1, ..., cm, e1, ..., ev.
C = Matrix([ni[:] for ni in N], DE.t) # rows n1, ..., ns.
return [hk.cancel(gamma, include=True) for hk in h], C
def limited_integrate_reduce(fa, fd, G, DE):
"""
Simpler version of step 1 & 2 for the limited integration problem.
Explanation
===========
Given a derivation D on k(t) and f, g1, ..., gn in k(t), return
(a, b, h, N, g, V) such that a, b, h in k[t], N is a non-negative integer,
g in k(t), V == [v1, ..., vm] in k(t)^m, and for any solution v in k(t),
c1, ..., cm in C of f == Dv + Sum(ci*wi, (i, 1, m)), p = v*h is in k<t>, and
p and the ci satisfy a*Dp + b*p == g + Sum(ci*vi, (i, 1, m)). Furthermore,
if S1irr == Sirr, then p is in k[t], and if t is nonlinear or Liouvillian
over k, then deg(p) <= N.
So that the special part is always computed, this function calls the more
general prde_special_denom() automatically if it cannot determine that
S1irr == Sirr. Furthermore, it will automatically call bound_degree() when
t is linear and non-Liouvillian, which for the transcendental case, implies
that Dt == a*t + b with for some a, b in k*.
"""
dn, ds = splitfactor(fd, DE)
E = [splitfactor(gd, DE) for _, gd in G]
En, Es = list(zip(*E))
c = reduce(lambda i, j: i.lcm(j), (dn,) + En) # lcm(dn, en1, ..., enm)
hn = c.gcd(c.diff(DE.t))
a = hn
b = -derivation(hn, DE)
N = 0
# These are the cases where we know that S1irr = Sirr, but there could be
# others, and this algorithm will need to be extended to handle them.
if DE.case in ('base', 'primitive', 'exp', 'tan'):
hs = reduce(lambda i, j: i.lcm(j), (ds,) + Es) # lcm(ds, es1, ..., esm)
a = hn*hs
b -= (hn*derivation(hs, DE)).quo(hs)
mu = min(order_at_oo(fa, fd, DE.t), min(order_at_oo(ga, gd, DE.t) for
ga, gd in G))
# So far, all the above are also nonlinear or Liouvillian, but if this
# changes, then this will need to be updated to call bound_degree()
# as per the docstring of this function (DE.case == 'other_linear').
N = hn.degree(DE.t) + hs.degree(DE.t) + max(0, 1 - DE.d.degree(DE.t) - mu)
else:
# TODO: implement this
raise NotImplementedError
V = [(-a*hn*ga).cancel(gd, include=True) for ga, gd in G]
return (a, b, a, N, (a*hn*fa).cancel(fd, include=True), V)
def limited_integrate(fa, fd, G, DE):
"""
Solves the limited integration problem: f = Dv + Sum(ci*wi, (i, 1, n))
"""
fa, fd = fa*Poly(1/fd.LC(), DE.t), fd.monic()
# interpreting limited integration problem as a
# parametric Risch DE problem
Fa = Poly(0, DE.t)
Fd = Poly(1, DE.t)
G = [(fa, fd)] + G
h, A = param_rischDE(Fa, Fd, G, DE)
V = A.nullspace()
V = [v for v in V if v[0] != 0]
if not V:
return None
else:
# we can take any vector from V, we take V[0]
c0 = V[0][0]
# v = [-1, c1, ..., cm, d1, ..., dr]
v = V[0]/(-c0)
r = len(h)
m = len(v) - r - 1
C = list(v[1: m + 1])
y = -sum(v[m + 1 + i]*h[i][0].as_expr()/h[i][1].as_expr() \
for i in range(r))
y_num, y_den = y.as_numer_denom()
Ya, Yd = Poly(y_num, DE.t), Poly(y_den, DE.t)
Y = Ya*Poly(1/Yd.LC(), DE.t), Yd.monic()
return Y, C
def parametric_log_deriv_heu(fa, fd, wa, wd, DE, c1=None):
"""
Parametric logarithmic derivative heuristic.
Explanation
===========
Given a derivation D on k[t], f in k(t), and a hyperexponential monomial
theta over k(t), raises either NotImplementedError, in which case the
heuristic failed, or returns None, in which case it has proven that no
solution exists, or returns a solution (n, m, v) of the equation
n*f == Dv/v + m*Dtheta/theta, with v in k(t)* and n, m in ZZ with n != 0.
If this heuristic fails, the structure theorem approach will need to be
used.
The argument w == Dtheta/theta
"""
# TODO: finish writing this and write tests
c1 = c1 or Dummy('c1')
p, a = fa.div(fd)
q, b = wa.div(wd)
B = max(0, derivation(DE.t, DE).degree(DE.t) - 1)
C = max(p.degree(DE.t), q.degree(DE.t))
if q.degree(DE.t) > B:
eqs = [p.nth(i) - c1*q.nth(i) for i in range(B + 1, C + 1)]
s = solve(eqs, c1)
if not s or not s[c1].is_Rational:
# deg(q) > B, no solution for c.
return None
M, N = s[c1].as_numer_denom()
M_poly = M.as_poly(q.gens)
N_poly = N.as_poly(q.gens)
nfmwa = N_poly*fa*wd - M_poly*wa*fd
nfmwd = fd*wd
Qv = is_log_deriv_k_t_radical_in_field(nfmwa, nfmwd, DE, 'auto')
if Qv is None:
# (N*f - M*w) is not the logarithmic derivative of a k(t)-radical.
return None
Q, v = Qv
if Q.is_zero or v.is_zero:
return None
return (Q*N, Q*M, v)
if p.degree(DE.t) > B:
return None
c = lcm(fd.as_poly(DE.t).LC(), wd.as_poly(DE.t).LC())
l = fd.monic().lcm(wd.monic())*Poly(c, DE.t)
ln, ls = splitfactor(l, DE)
z = ls*ln.gcd(ln.diff(DE.t))
if not z.has(DE.t):
# TODO: We treat this as 'no solution', until the structure
# theorem version of parametric_log_deriv is implemented.
return None
u1, r1 = (fa*l.quo(fd)).div(z) # (l*f).div(z)
u2, r2 = (wa*l.quo(wd)).div(z) # (l*w).div(z)
eqs = [r1.nth(i) - c1*r2.nth(i) for i in range(z.degree(DE.t))]
s = solve(eqs, c1)
if not s or not s[c1].is_Rational:
# deg(q) <= B, no solution for c.
return None
M, N = s[c1].as_numer_denom()
nfmwa = N.as_poly(DE.t)*fa*wd - M.as_poly(DE.t)*wa*fd
nfmwd = fd*wd
Qv = is_log_deriv_k_t_radical_in_field(nfmwa, nfmwd, DE)
if Qv is None:
# (N*f - M*w) is not the logarithmic derivative of a k(t)-radical.
return None
Q, v = Qv
if Q.is_zero or v.is_zero:
return None
return (Q*N, Q*M, v)
def parametric_log_deriv(fa, fd, wa, wd, DE):
# TODO: Write the full algorithm using the structure theorems.
# try:
A = parametric_log_deriv_heu(fa, fd, wa, wd, DE)
# except NotImplementedError:
# Heuristic failed, we have to use the full method.
# TODO: This could be implemented more efficiently.
# It isn't too worrisome, because the heuristic handles most difficult
# cases.
return A
def is_deriv_k(fa, fd, DE):
r"""
Checks if Df/f is the derivative of an element of k(t).
Explanation
===========
a in k(t) is the derivative of an element of k(t) if there exists b in k(t)
such that a = Db. Either returns (ans, u), such that Df/f == Du, or None,
which means that Df/f is not the derivative of an element of k(t). ans is
a list of tuples such that Add(*[i*j for i, j in ans]) == u. This is useful
for seeing exactly which elements of k(t) produce u.
This function uses the structure theorem approach, which says that for any
f in K, Df/f is the derivative of a element of K if and only if there are ri
in QQ such that::
--- --- Dt
\ r * Dt + \ r * i Df
/ i i / i --- = --.
--- --- t f
i in L i in E i
K/C(x) K/C(x)
Where C = Const(K), L_K/C(x) = { i in {1, ..., n} such that t_i is
transcendental over C(x)(t_1, ..., t_i-1) and Dt_i = Da_i/a_i, for some a_i
in C(x)(t_1, ..., t_i-1)* } (i.e., the set of all indices of logarithmic
monomials of K over C(x)), and E_K/C(x) = { i in {1, ..., n} such that t_i
is transcendental over C(x)(t_1, ..., t_i-1) and Dt_i/t_i = Da_i, for some
a_i in C(x)(t_1, ..., t_i-1) } (i.e., the set of all indices of
hyperexponential monomials of K over C(x)). If K is an elementary extension
over C(x), then the cardinality of L_K/C(x) U E_K/C(x) is exactly the
transcendence degree of K over C(x). Furthermore, because Const_D(K) ==
Const_D(C(x)) == C, deg(Dt_i) == 1 when t_i is in E_K/C(x) and
deg(Dt_i) == 0 when t_i is in L_K/C(x), implying in particular that E_K/C(x)
and L_K/C(x) are disjoint.
The sets L_K/C(x) and E_K/C(x) must, by their nature, be computed
recursively using this same function. Therefore, it is required to pass
them as indices to D (or T). E_args are the arguments of the
hyperexponentials indexed by E_K (i.e., if i is in E_K, then T[i] ==
exp(E_args[i])). This is needed to compute the final answer u such that
Df/f == Du.
log(f) will be the same as u up to a additive constant. This is because
they will both behave the same as monomials. For example, both log(x) and
log(2*x) == log(x) + log(2) satisfy Dt == 1/x, because log(2) is constant.
Therefore, the term const is returned. const is such that
log(const) + f == u. This is calculated by dividing the arguments of one
logarithm from the other. Therefore, it is necessary to pass the arguments
of the logarithmic terms in L_args.
To handle the case where we are given Df/f, not f, use is_deriv_k_in_field().
See also
========
is_log_deriv_k_t_radical_in_field, is_log_deriv_k_t_radical
"""
# Compute Df/f
dfa, dfd = (fd*derivation(fa, DE) - fa*derivation(fd, DE)), fd*fa
dfa, dfd = dfa.cancel(dfd, include=True)
# Our assumption here is that each monomial is recursively transcendental
if len(DE.exts) != len(DE.D):
if [i for i in DE.cases if i == 'tan'] or \
({i for i in DE.cases if i == 'primitive'} -
set(DE.indices('log'))):
raise NotImplementedError("Real version of the structure "
"theorems with hypertangent support is not yet implemented.")
# TODO: What should really be done in this case?
raise NotImplementedError("Nonelementary extensions not supported "
"in the structure theorems.")
E_part = [DE.D[i].quo(Poly(DE.T[i], DE.T[i])).as_expr() for i in DE.indices('exp')]
L_part = [DE.D[i].as_expr() for i in DE.indices('log')]
# The expression dfa/dfd might not be polynomial in any of its symbols so we
# use a Dummy as the generator for PolyMatrix.
dum = Dummy()
lhs = Matrix([E_part + L_part], dum)
rhs = Matrix([dfa.as_expr()/dfd.as_expr()], dum)
A, u = constant_system(lhs, rhs, DE)
u = u.to_Matrix() # Poly to Expr
if not A or not all(derivation(i, DE, basic=True).is_zero for i in u):
# If the elements of u are not all constant
# Note: See comment in constant_system
# Also note: derivation(basic=True) calls cancel()
return None
else:
if not all(i.is_Rational for i in u):
raise NotImplementedError("Cannot work with non-rational "
"coefficients in this case.")
else:
terms = ([DE.extargs[i] for i in DE.indices('exp')] +
[DE.T[i] for i in DE.indices('log')])
ans = list(zip(terms, u))
result = Add(*[Mul(i, j) for i, j in ans])
argterms = ([DE.T[i] for i in DE.indices('exp')] +
[DE.extargs[i] for i in DE.indices('log')])
l = []
ld = []
for i, j in zip(argterms, u):
# We need to get around things like sqrt(x**2) != x
# and also sqrt(x**2 + 2*x + 1) != x + 1
# Issue 10798: i need not be a polynomial
i, d = i.as_numer_denom()
icoeff, iterms = sqf_list(i)
l.append(Mul(*([Pow(icoeff, j)] + [Pow(b, e*j) for b, e in iterms])))
dcoeff, dterms = sqf_list(d)
ld.append(Mul(*([Pow(dcoeff, j)] + [Pow(b, e*j) for b, e in dterms])))
const = cancel(fa.as_expr()/fd.as_expr()/Mul(*l)*Mul(*ld))
return (ans, result, const)
def is_log_deriv_k_t_radical(fa, fd, DE, Df=True):
r"""
Checks if Df is the logarithmic derivative of a k(t)-radical.
Explanation
===========
b in k(t) can be written as the logarithmic derivative of a k(t) radical if
there exist n in ZZ and u in k(t) with n, u != 0 such that n*b == Du/u.
Either returns (ans, u, n, const) or None, which means that Df cannot be
written as the logarithmic derivative of a k(t)-radical. ans is a list of
tuples such that Mul(*[i**j for i, j in ans]) == u. This is useful for
seeing exactly what elements of k(t) produce u.
This function uses the structure theorem approach, which says that for any
f in K, Df is the logarithmic derivative of a K-radical if and only if there
are ri in QQ such that::
--- --- Dt
\ r * Dt + \ r * i
/ i i / i --- = Df.
--- --- t
i in L i in E i
K/C(x) K/C(x)
Where C = Const(K), L_K/C(x) = { i in {1, ..., n} such that t_i is
transcendental over C(x)(t_1, ..., t_i-1) and Dt_i = Da_i/a_i, for some a_i
in C(x)(t_1, ..., t_i-1)* } (i.e., the set of all indices of logarithmic
monomials of K over C(x)), and E_K/C(x) = { i in {1, ..., n} such that t_i
is transcendental over C(x)(t_1, ..., t_i-1) and Dt_i/t_i = Da_i, for some
a_i in C(x)(t_1, ..., t_i-1) } (i.e., the set of all indices of
hyperexponential monomials of K over C(x)). If K is an elementary extension
over C(x), then the cardinality of L_K/C(x) U E_K/C(x) is exactly the
transcendence degree of K over C(x). Furthermore, because Const_D(K) ==
Const_D(C(x)) == C, deg(Dt_i) == 1 when t_i is in E_K/C(x) and
deg(Dt_i) == 0 when t_i is in L_K/C(x), implying in particular that E_K/C(x)
and L_K/C(x) are disjoint.
The sets L_K/C(x) and E_K/C(x) must, by their nature, be computed
recursively using this same function. Therefore, it is required to pass
them as indices to D (or T). L_args are the arguments of the logarithms
indexed by L_K (i.e., if i is in L_K, then T[i] == log(L_args[i])). This is
needed to compute the final answer u such that n*f == Du/u.
exp(f) will be the same as u up to a multiplicative constant. This is
because they will both behave the same as monomials. For example, both
exp(x) and exp(x + 1) == E*exp(x) satisfy Dt == t. Therefore, the term const
is returned. const is such that exp(const)*f == u. This is calculated by
subtracting the arguments of one exponential from the other. Therefore, it
is necessary to pass the arguments of the exponential terms in E_args.
To handle the case where we are given Df, not f, use
is_log_deriv_k_t_radical_in_field().
See also
========
is_log_deriv_k_t_radical_in_field, is_deriv_k
"""
if Df:
dfa, dfd = (fd*derivation(fa, DE) - fa*derivation(fd, DE)).cancel(fd**2,
include=True)
else:
dfa, dfd = fa, fd
# Our assumption here is that each monomial is recursively transcendental
if len(DE.exts) != len(DE.D):
if [i for i in DE.cases if i == 'tan'] or \
({i for i in DE.cases if i == 'primitive'} -
set(DE.indices('log'))):
raise NotImplementedError("Real version of the structure "
"theorems with hypertangent support is not yet implemented.")
# TODO: What should really be done in this case?
raise NotImplementedError("Nonelementary extensions not supported "
"in the structure theorems.")
E_part = [DE.D[i].quo(Poly(DE.T[i], DE.T[i])).as_expr() for i in DE.indices('exp')]
L_part = [DE.D[i].as_expr() for i in DE.indices('log')]
# The expression dfa/dfd might not be polynomial in any of its symbols so we
# use a Dummy as the generator for PolyMatrix.
dum = Dummy()
lhs = Matrix([E_part + L_part], dum)
rhs = Matrix([dfa.as_expr()/dfd.as_expr()], dum)
A, u = constant_system(lhs, rhs, DE)
u = u.to_Matrix() # Poly to Expr
if not A or not all(derivation(i, DE, basic=True).is_zero for i in u):
# If the elements of u are not all constant
# Note: See comment in constant_system
# Also note: derivation(basic=True) calls cancel()
return None
else:
if not all(i.is_Rational for i in u):
# TODO: But maybe we can tell if they're not rational, like
# log(2)/log(3). Also, there should be an option to continue
# anyway, even if the result might potentially be wrong.
raise NotImplementedError("Cannot work with non-rational "
"coefficients in this case.")
else:
n = S.One*reduce(ilcm, [i.as_numer_denom()[1] for i in u])
u *= n
terms = ([DE.T[i] for i in DE.indices('exp')] +
[DE.extargs[i] for i in DE.indices('log')])
ans = list(zip(terms, u))
result = Mul(*[Pow(i, j) for i, j in ans])
# exp(f) will be the same as result up to a multiplicative
# constant. We now find the log of that constant.
argterms = ([DE.extargs[i] for i in DE.indices('exp')] +
[DE.T[i] for i in DE.indices('log')])
const = cancel(fa.as_expr()/fd.as_expr() -
Add(*[Mul(i, j/n) for i, j in zip(argterms, u)]))
return (ans, result, n, const)
def is_log_deriv_k_t_radical_in_field(fa, fd, DE, case='auto', z=None):
"""
Checks if f can be written as the logarithmic derivative of a k(t)-radical.
Explanation
===========
It differs from is_log_deriv_k_t_radical(fa, fd, DE, Df=False)
for any given fa, fd, DE in that it finds the solution in the
given field not in some (possibly unspecified extension) and
"in_field" with the function name is used to indicate that.
f in k(t) can be written as the logarithmic derivative of a k(t) radical if
there exist n in ZZ and u in k(t) with n, u != 0 such that n*f == Du/u.
Either returns (n, u) or None, which means that f cannot be written as the
logarithmic derivative of a k(t)-radical.
case is one of {'primitive', 'exp', 'tan', 'auto'} for the primitive,
hyperexponential, and hypertangent cases, respectively. If case is 'auto',
it will attempt to determine the type of the derivation automatically.
See also
========
is_log_deriv_k_t_radical, is_deriv_k
"""
fa, fd = fa.cancel(fd, include=True)
# f must be simple
n, s = splitfactor(fd, DE)
if not s.is_one:
pass
z = z or Dummy('z')
H, b = residue_reduce(fa, fd, DE, z=z)
if not b:
# I will have to verify, but I believe that the answer should be
# None in this case. This should never happen for the
# functions given when solving the parametric logarithmic
# derivative problem when integration elementary functions (see
# Bronstein's book, page 255), so most likely this indicates a bug.
return None
roots = [(i, i.real_roots()) for i, _ in H]
if not all(len(j) == i.degree() and all(k.is_Rational for k in j) for
i, j in roots):
# If f is the logarithmic derivative of a k(t)-radical, then all the
# roots of the resultant must be rational numbers.
return None
# [(a, i), ...], where i*log(a) is a term in the log-part of the integral
# of f
respolys, residues = list(zip(*roots)) or [[], []]
# Note: this might be empty, but everything below should work find in that
# case (it should be the same as if it were [[1, 1]])
residueterms = [(H[j][1].subs(z, i), i) for j in range(len(H)) for
i in residues[j]]
# TODO: finish writing this and write tests
p = cancel(fa.as_expr()/fd.as_expr() - residue_reduce_derivation(H, DE, z))
p = p.as_poly(DE.t)
if p is None:
# f - Dg will be in k[t] if f is the logarithmic derivative of a k(t)-radical
return None
if p.degree(DE.t) >= max(1, DE.d.degree(DE.t)):
return None
if case == 'auto':
case = DE.case
if case == 'exp':
wa, wd = derivation(DE.t, DE).cancel(Poly(DE.t, DE.t), include=True)
with DecrementLevel(DE):
pa, pd = frac_in(p, DE.t, cancel=True)
wa, wd = frac_in((wa, wd), DE.t)
A = parametric_log_deriv(pa, pd, wa, wd, DE)
if A is None:
return None
n, e, u = A
u *= DE.t**e
elif case == 'primitive':
with DecrementLevel(DE):
pa, pd = frac_in(p, DE.t)
A = is_log_deriv_k_t_radical_in_field(pa, pd, DE, case='auto')
if A is None:
return None
n, u = A
elif case == 'base':
# TODO: we can use more efficient residue reduction from ratint()
if not fd.is_sqf or fa.degree() >= fd.degree():
# f is the logarithmic derivative in the base case if and only if
# f = fa/fd, fd is square-free, deg(fa) < deg(fd), and
# gcd(fa, fd) == 1. The last condition is handled by cancel() above.
return None
# Note: if residueterms = [], returns (1, 1)
# f had better be 0 in that case.
n = S.One*reduce(ilcm, [i.as_numer_denom()[1] for _, i in residueterms], 1)
u = Mul(*[Pow(i, j*n) for i, j in residueterms])
return (n, u)
elif case == 'tan':
raise NotImplementedError("The hypertangent case is "
"not yet implemented for is_log_deriv_k_t_radical_in_field()")
elif case in ('other_linear', 'other_nonlinear'):
# XXX: If these are supported by the structure theorems, change to NotImplementedError.
raise ValueError("The %s case is not supported in this function." % case)
else:
raise ValueError("case must be one of {'primitive', 'exp', 'tan', "
"'base', 'auto'}, not %s" % case)
common_denom = S.One*reduce(ilcm, [i.as_numer_denom()[1] for i in [j for _, j in
residueterms]] + [n], 1)
residueterms = [(i, j*common_denom) for i, j in residueterms]
m = common_denom//n
if common_denom != n*m: # Verify exact division
raise ValueError("Inexact division")
u = cancel(u**m*Mul(*[Pow(i, j) for i, j in residueterms]))
return (common_denom, u)
PK ]ZZZ�%AܨB �B sympy/integrals/quadrature.pyfrom sympy.core import S, Dummy, pi
from sympy.functions.combinatorial.factorials import factorial
from sympy.functions.elementary.trigonometric import sin, cos
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.special.gamma_functions import gamma
from sympy.polys.orthopolys import (legendre_poly, laguerre_poly,
hermite_poly, jacobi_poly)
from sympy.polys.rootoftools import RootOf
def gauss_legendre(n, n_digits):
r"""
Computes the Gauss-Legendre quadrature [1]_ points and weights.
Explanation
===========
The Gauss-Legendre quadrature approximates the integral:
.. math::
\int_{-1}^1 f(x)\,dx \approx \sum_{i=1}^n w_i f(x_i)
The nodes `x_i` of an order `n` quadrature rule are the roots of `P_n`
and the weights `w_i` are given by:
.. math::
w_i = \frac{2}{\left(1-x_i^2\right) \left(P'_n(x_i)\right)^2}
Parameters
==========
n :
The order of quadrature.
n_digits :
Number of significant digits of the points and weights to return.
Returns
=======
(x, w) : the ``x`` and ``w`` are lists of points and weights as Floats.
The points `x_i` and weights `w_i` are returned as ``(x, w)``
tuple of lists.
Examples
========
>>> from sympy.integrals.quadrature import gauss_legendre
>>> x, w = gauss_legendre(3, 5)
>>> x
[-0.7746, 0, 0.7746]
>>> w
[0.55556, 0.88889, 0.55556]
>>> x, w = gauss_legendre(4, 5)
>>> x
[-0.86114, -0.33998, 0.33998, 0.86114]
>>> w
[0.34785, 0.65215, 0.65215, 0.34785]
See Also
========
gauss_laguerre, gauss_gen_laguerre, gauss_hermite, gauss_chebyshev_t, gauss_chebyshev_u, gauss_jacobi, gauss_lobatto
References
==========
.. [1] https://en.wikipedia.org/wiki/Gaussian_quadrature
.. [2] https://people.sc.fsu.edu/~jburkardt/cpp_src/legendre_rule/legendre_rule.html
"""
x = Dummy("x")
p = legendre_poly(n, x, polys=True)
pd = p.diff(x)
xi = []
w = []
for r in p.real_roots():
if isinstance(r, RootOf):
r = r.eval_rational(S.One/10**(n_digits+2))
xi.append(r.n(n_digits))
w.append((2/((1-r**2) * pd.subs(x, r)**2)).n(n_digits))
return xi, w
def gauss_laguerre(n, n_digits):
r"""
Computes the Gauss-Laguerre quadrature [1]_ points and weights.
Explanation
===========
The Gauss-Laguerre quadrature approximates the integral:
.. math::
\int_0^{\infty} e^{-x} f(x)\,dx \approx \sum_{i=1}^n w_i f(x_i)
The nodes `x_i` of an order `n` quadrature rule are the roots of `L_n`
and the weights `w_i` are given by:
.. math::
w_i = \frac{x_i}{(n+1)^2 \left(L_{n+1}(x_i)\right)^2}
Parameters
==========
n :
The order of quadrature.
n_digits :
Number of significant digits of the points and weights to return.
Returns
=======
(x, w) : The ``x`` and ``w`` are lists of points and weights as Floats.
The points `x_i` and weights `w_i` are returned as ``(x, w)``
tuple of lists.
Examples
========
>>> from sympy.integrals.quadrature import gauss_laguerre
>>> x, w = gauss_laguerre(3, 5)
>>> x
[0.41577, 2.2943, 6.2899]
>>> w
[0.71109, 0.27852, 0.010389]
>>> x, w = gauss_laguerre(6, 5)
>>> x
[0.22285, 1.1889, 2.9927, 5.7751, 9.8375, 15.983]
>>> w
[0.45896, 0.417, 0.11337, 0.010399, 0.00026102, 8.9855e-7]
See Also
========
gauss_legendre, gauss_gen_laguerre, gauss_hermite, gauss_chebyshev_t, gauss_chebyshev_u, gauss_jacobi, gauss_lobatto
References
==========
.. [1] https://en.wikipedia.org/wiki/Gauss%E2%80%93Laguerre_quadrature
.. [2] https://people.sc.fsu.edu/~jburkardt/cpp_src/laguerre_rule/laguerre_rule.html
"""
x = Dummy("x")
p = laguerre_poly(n, x, polys=True)
p1 = laguerre_poly(n+1, x, polys=True)
xi = []
w = []
for r in p.real_roots():
if isinstance(r, RootOf):
r = r.eval_rational(S.One/10**(n_digits+2))
xi.append(r.n(n_digits))
w.append((r/((n+1)**2 * p1.subs(x, r)**2)).n(n_digits))
return xi, w
def gauss_hermite(n, n_digits):
r"""
Computes the Gauss-Hermite quadrature [1]_ points and weights.
Explanation
===========
The Gauss-Hermite quadrature approximates the integral:
.. math::
\int_{-\infty}^{\infty} e^{-x^2} f(x)\,dx \approx
\sum_{i=1}^n w_i f(x_i)
The nodes `x_i` of an order `n` quadrature rule are the roots of `H_n`
and the weights `w_i` are given by:
.. math::
w_i = \frac{2^{n-1} n! \sqrt{\pi}}{n^2 \left(H_{n-1}(x_i)\right)^2}
Parameters
==========
n :
The order of quadrature.
n_digits :
Number of significant digits of the points and weights to return.
Returns
=======
(x, w) : The ``x`` and ``w`` are lists of points and weights as Floats.
The points `x_i` and weights `w_i` are returned as ``(x, w)``
tuple of lists.
Examples
========
>>> from sympy.integrals.quadrature import gauss_hermite
>>> x, w = gauss_hermite(3, 5)
>>> x
[-1.2247, 0, 1.2247]
>>> w
[0.29541, 1.1816, 0.29541]
>>> x, w = gauss_hermite(6, 5)
>>> x
[-2.3506, -1.3358, -0.43608, 0.43608, 1.3358, 2.3506]
>>> w
[0.00453, 0.15707, 0.72463, 0.72463, 0.15707, 0.00453]
See Also
========
gauss_legendre, gauss_laguerre, gauss_gen_laguerre, gauss_chebyshev_t, gauss_chebyshev_u, gauss_jacobi, gauss_lobatto
References
==========
.. [1] https://en.wikipedia.org/wiki/Gauss-Hermite_Quadrature
.. [2] https://people.sc.fsu.edu/~jburkardt/cpp_src/hermite_rule/hermite_rule.html
.. [3] https://people.sc.fsu.edu/~jburkardt/cpp_src/gen_hermite_rule/gen_hermite_rule.html
"""
x = Dummy("x")
p = hermite_poly(n, x, polys=True)
p1 = hermite_poly(n-1, x, polys=True)
xi = []
w = []
for r in p.real_roots():
if isinstance(r, RootOf):
r = r.eval_rational(S.One/10**(n_digits+2))
xi.append(r.n(n_digits))
w.append(((2**(n-1) * factorial(n) * sqrt(pi)) /
(n**2 * p1.subs(x, r)**2)).n(n_digits))
return xi, w
def gauss_gen_laguerre(n, alpha, n_digits):
r"""
Computes the generalized Gauss-Laguerre quadrature [1]_ points and weights.
Explanation
===========
The generalized Gauss-Laguerre quadrature approximates the integral:
.. math::
\int_{0}^\infty x^{\alpha} e^{-x} f(x)\,dx \approx
\sum_{i=1}^n w_i f(x_i)
The nodes `x_i` of an order `n` quadrature rule are the roots of
`L^{\alpha}_n` and the weights `w_i` are given by:
.. math::
w_i = \frac{\Gamma(\alpha+n)}
{n \Gamma(n) L^{\alpha}_{n-1}(x_i) L^{\alpha+1}_{n-1}(x_i)}
Parameters
==========
n :
The order of quadrature.
alpha :
The exponent of the singularity, `\alpha > -1`.
n_digits :
Number of significant digits of the points and weights to return.
Returns
=======
(x, w) : the ``x`` and ``w`` are lists of points and weights as Floats.
The points `x_i` and weights `w_i` are returned as ``(x, w)``
tuple of lists.
Examples
========
>>> from sympy import S
>>> from sympy.integrals.quadrature import gauss_gen_laguerre
>>> x, w = gauss_gen_laguerre(3, -S.Half, 5)
>>> x
[0.19016, 1.7845, 5.5253]
>>> w
[1.4493, 0.31413, 0.00906]
>>> x, w = gauss_gen_laguerre(4, 3*S.Half, 5)
>>> x
[0.97851, 2.9904, 6.3193, 11.712]
>>> w
[0.53087, 0.67721, 0.11895, 0.0023152]
See Also
========
gauss_legendre, gauss_laguerre, gauss_hermite, gauss_chebyshev_t, gauss_chebyshev_u, gauss_jacobi, gauss_lobatto
References
==========
.. [1] https://en.wikipedia.org/wiki/Gauss%E2%80%93Laguerre_quadrature
.. [2] https://people.sc.fsu.edu/~jburkardt/cpp_src/gen_laguerre_rule/gen_laguerre_rule.html
"""
x = Dummy("x")
p = laguerre_poly(n, x, alpha=alpha, polys=True)
p1 = laguerre_poly(n-1, x, alpha=alpha, polys=True)
p2 = laguerre_poly(n-1, x, alpha=alpha+1, polys=True)
xi = []
w = []
for r in p.real_roots():
if isinstance(r, RootOf):
r = r.eval_rational(S.One/10**(n_digits+2))
xi.append(r.n(n_digits))
w.append((gamma(alpha+n) /
(n*gamma(n)*p1.subs(x, r)*p2.subs(x, r))).n(n_digits))
return xi, w
def gauss_chebyshev_t(n, n_digits):
r"""
Computes the Gauss-Chebyshev quadrature [1]_ points and weights of
the first kind.
Explanation
===========
The Gauss-Chebyshev quadrature of the first kind approximates the integral:
.. math::
\int_{-1}^{1} \frac{1}{\sqrt{1-x^2}} f(x)\,dx \approx
\sum_{i=1}^n w_i f(x_i)
The nodes `x_i` of an order `n` quadrature rule are the roots of `T_n`
and the weights `w_i` are given by:
.. math::
w_i = \frac{\pi}{n}
Parameters
==========
n :
The order of quadrature.
n_digits :
Number of significant digits of the points and weights to return.
Returns
=======
(x, w) : the ``x`` and ``w`` are lists of points and weights as Floats.
The points `x_i` and weights `w_i` are returned as ``(x, w)``
tuple of lists.
Examples
========
>>> from sympy.integrals.quadrature import gauss_chebyshev_t
>>> x, w = gauss_chebyshev_t(3, 5)
>>> x
[0.86602, 0, -0.86602]
>>> w
[1.0472, 1.0472, 1.0472]
>>> x, w = gauss_chebyshev_t(6, 5)
>>> x
[0.96593, 0.70711, 0.25882, -0.25882, -0.70711, -0.96593]
>>> w
[0.5236, 0.5236, 0.5236, 0.5236, 0.5236, 0.5236]
See Also
========
gauss_legendre, gauss_laguerre, gauss_hermite, gauss_gen_laguerre, gauss_chebyshev_u, gauss_jacobi, gauss_lobatto
References
==========
.. [1] https://en.wikipedia.org/wiki/Chebyshev%E2%80%93Gauss_quadrature
.. [2] https://people.sc.fsu.edu/~jburkardt/cpp_src/chebyshev1_rule/chebyshev1_rule.html
"""
xi = []
w = []
for i in range(1, n+1):
xi.append((cos((2*i-S.One)/(2*n)*S.Pi)).n(n_digits))
w.append((S.Pi/n).n(n_digits))
return xi, w
def gauss_chebyshev_u(n, n_digits):
r"""
Computes the Gauss-Chebyshev quadrature [1]_ points and weights of
the second kind.
Explanation
===========
The Gauss-Chebyshev quadrature of the second kind approximates the
integral:
.. math::
\int_{-1}^{1} \sqrt{1-x^2} f(x)\,dx \approx \sum_{i=1}^n w_i f(x_i)
The nodes `x_i` of an order `n` quadrature rule are the roots of `U_n`
and the weights `w_i` are given by:
.. math::
w_i = \frac{\pi}{n+1} \sin^2 \left(\frac{i}{n+1}\pi\right)
Parameters
==========
n : the order of quadrature
n_digits : number of significant digits of the points and weights to return
Returns
=======
(x, w) : the ``x`` and ``w`` are lists of points and weights as Floats.
The points `x_i` and weights `w_i` are returned as ``(x, w)``
tuple of lists.
Examples
========
>>> from sympy.integrals.quadrature import gauss_chebyshev_u
>>> x, w = gauss_chebyshev_u(3, 5)
>>> x
[0.70711, 0, -0.70711]
>>> w
[0.3927, 0.7854, 0.3927]
>>> x, w = gauss_chebyshev_u(6, 5)
>>> x
[0.90097, 0.62349, 0.22252, -0.22252, -0.62349, -0.90097]
>>> w
[0.084489, 0.27433, 0.42658, 0.42658, 0.27433, 0.084489]
See Also
========
gauss_legendre, gauss_laguerre, gauss_hermite, gauss_gen_laguerre, gauss_chebyshev_t, gauss_jacobi, gauss_lobatto
References
==========
.. [1] https://en.wikipedia.org/wiki/Chebyshev%E2%80%93Gauss_quadrature
.. [2] https://people.sc.fsu.edu/~jburkardt/cpp_src/chebyshev2_rule/chebyshev2_rule.html
"""
xi = []
w = []
for i in range(1, n+1):
xi.append((cos(i/(n+S.One)*S.Pi)).n(n_digits))
w.append((S.Pi/(n+S.One)*sin(i*S.Pi/(n+S.One))**2).n(n_digits))
return xi, w
def gauss_jacobi(n, alpha, beta, n_digits):
r"""
Computes the Gauss-Jacobi quadrature [1]_ points and weights.
Explanation
===========
The Gauss-Jacobi quadrature of the first kind approximates the integral:
.. math::
\int_{-1}^1 (1-x)^\alpha (1+x)^\beta f(x)\,dx \approx
\sum_{i=1}^n w_i f(x_i)
The nodes `x_i` of an order `n` quadrature rule are the roots of
`P^{(\alpha,\beta)}_n` and the weights `w_i` are given by:
.. math::
w_i = -\frac{2n+\alpha+\beta+2}{n+\alpha+\beta+1}
\frac{\Gamma(n+\alpha+1)\Gamma(n+\beta+1)}
{\Gamma(n+\alpha+\beta+1)(n+1)!}
\frac{2^{\alpha+\beta}}{P'_n(x_i)
P^{(\alpha,\beta)}_{n+1}(x_i)}
Parameters
==========
n : the order of quadrature
alpha : the first parameter of the Jacobi Polynomial, `\alpha > -1`
beta : the second parameter of the Jacobi Polynomial, `\beta > -1`
n_digits : number of significant digits of the points and weights to return
Returns
=======
(x, w) : the ``x`` and ``w`` are lists of points and weights as Floats.
The points `x_i` and weights `w_i` are returned as ``(x, w)``
tuple of lists.
Examples
========
>>> from sympy import S
>>> from sympy.integrals.quadrature import gauss_jacobi
>>> x, w = gauss_jacobi(3, S.Half, -S.Half, 5)
>>> x
[-0.90097, -0.22252, 0.62349]
>>> w
[1.7063, 1.0973, 0.33795]
>>> x, w = gauss_jacobi(6, 1, 1, 5)
>>> x
[-0.87174, -0.5917, -0.2093, 0.2093, 0.5917, 0.87174]
>>> w
[0.050584, 0.22169, 0.39439, 0.39439, 0.22169, 0.050584]
See Also
========
gauss_legendre, gauss_laguerre, gauss_hermite, gauss_gen_laguerre,
gauss_chebyshev_t, gauss_chebyshev_u, gauss_lobatto
References
==========
.. [1] https://en.wikipedia.org/wiki/Gauss%E2%80%93Jacobi_quadrature
.. [2] https://people.sc.fsu.edu/~jburkardt/cpp_src/jacobi_rule/jacobi_rule.html
.. [3] https://people.sc.fsu.edu/~jburkardt/cpp_src/gegenbauer_rule/gegenbauer_rule.html
"""
x = Dummy("x")
p = jacobi_poly(n, alpha, beta, x, polys=True)
pd = p.diff(x)
pn = jacobi_poly(n+1, alpha, beta, x, polys=True)
xi = []
w = []
for r in p.real_roots():
if isinstance(r, RootOf):
r = r.eval_rational(S.One/10**(n_digits+2))
xi.append(r.n(n_digits))
w.append((
- (2*n+alpha+beta+2) / (n+alpha+beta+S.One) *
(gamma(n+alpha+1)*gamma(n+beta+1)) /
(gamma(n+alpha+beta+S.One)*gamma(n+2)) *
2**(alpha+beta) / (pd.subs(x, r) * pn.subs(x, r))).n(n_digits))
return xi, w
def gauss_lobatto(n, n_digits):
r"""
Computes the Gauss-Lobatto quadrature [1]_ points and weights.
Explanation
===========
The Gauss-Lobatto quadrature approximates the integral:
.. math::
\int_{-1}^1 f(x)\,dx \approx \sum_{i=1}^n w_i f(x_i)
The nodes `x_i` of an order `n` quadrature rule are the roots of `P'_(n-1)`
and the weights `w_i` are given by:
.. math::
&w_i = \frac{2}{n(n-1) \left[P_{n-1}(x_i)\right]^2},\quad x\neq\pm 1\\
&w_i = \frac{2}{n(n-1)},\quad x=\pm 1
Parameters
==========
n : the order of quadrature
n_digits : number of significant digits of the points and weights to return
Returns
=======
(x, w) : the ``x`` and ``w`` are lists of points and weights as Floats.
The points `x_i` and weights `w_i` are returned as ``(x, w)``
tuple of lists.
Examples
========
>>> from sympy.integrals.quadrature import gauss_lobatto
>>> x, w = gauss_lobatto(3, 5)
>>> x
[-1, 0, 1]
>>> w
[0.33333, 1.3333, 0.33333]
>>> x, w = gauss_lobatto(4, 5)
>>> x
[-1, -0.44721, 0.44721, 1]
>>> w
[0.16667, 0.83333, 0.83333, 0.16667]
See Also
========
gauss_legendre,gauss_laguerre, gauss_gen_laguerre, gauss_hermite, gauss_chebyshev_t, gauss_chebyshev_u, gauss_jacobi
References
==========
.. [1] https://en.wikipedia.org/wiki/Gaussian_quadrature#Gauss.E2.80.93Lobatto_rules
.. [2] https://web.archive.org/web/20200118141346/http://people.math.sfu.ca/~cbm/aands/page_888.htm
"""
x = Dummy("x")
p = legendre_poly(n-1, x, polys=True)
pd = p.diff(x)
xi = []
w = []
for r in pd.real_roots():
if isinstance(r, RootOf):
r = r.eval_rational(S.One/10**(n_digits+2))
xi.append(r.n(n_digits))
w.append((2/(n*(n-1) * p.subs(x, r)**2)).n(n_digits))
xi.insert(0, -1)
xi.append(1)
w.insert(0, (S(2)/(n*(n-1))).n(n_digits))
w.append((S(2)/(n*(n-1))).n(n_digits))
return xi, w
PK ]ZZZm���, �, sympy/integrals/rationaltools.py"""This module implements tools for integrating rational functions. """
from sympy.core.function import Lambda
from sympy.core.numbers import I
from sympy.core.singleton import S
from sympy.core.symbol import (Dummy, Symbol, symbols)
from sympy.functions.elementary.exponential import log
from sympy.functions.elementary.trigonometric import atan
from sympy.polys.polyroots import roots
from sympy.polys.polytools import cancel
from sympy.polys.rootoftools import RootSum
from sympy.polys import Poly, resultant, ZZ
def ratint(f, x, **flags):
"""
Performs indefinite integration of rational functions.
Explanation
===========
Given a field :math:`K` and a rational function :math:`f = p/q`,
where :math:`p` and :math:`q` are polynomials in :math:`K[x]`,
returns a function :math:`g` such that :math:`f = g'`.
Examples
========
>>> from sympy.integrals.rationaltools import ratint
>>> from sympy.abc import x
>>> ratint(36/(x**5 - 2*x**4 - 2*x**3 + 4*x**2 + x - 2), x)
(12*x + 6)/(x**2 - 1) + 4*log(x - 2) - 4*log(x + 1)
References
==========
.. [1] M. Bronstein, Symbolic Integration I: Transcendental
Functions, Second Edition, Springer-Verlag, 2005, pp. 35-70
See Also
========
sympy.integrals.integrals.Integral.doit
sympy.integrals.rationaltools.ratint_logpart
sympy.integrals.rationaltools.ratint_ratpart
"""
if isinstance(f, tuple):
p, q = f
else:
p, q = f.as_numer_denom()
p, q = Poly(p, x, composite=False, field=True), Poly(q, x, composite=False, field=True)
coeff, p, q = p.cancel(q)
poly, p = p.div(q)
result = poly.integrate(x).as_expr()
if p.is_zero:
return coeff*result
g, h = ratint_ratpart(p, q, x)
P, Q = h.as_numer_denom()
P = Poly(P, x)
Q = Poly(Q, x)
q, r = P.div(Q)
result += g + q.integrate(x).as_expr()
if not r.is_zero:
symbol = flags.get('symbol', 't')
if not isinstance(symbol, Symbol):
t = Dummy(symbol)
else:
t = symbol.as_dummy()
L = ratint_logpart(r, Q, x, t)
real = flags.get('real')
if real is None:
if isinstance(f, tuple):
p, q = f
atoms = p.atoms() | q.atoms()
else:
atoms = f.atoms()
for elt in atoms - {x}:
if not elt.is_extended_real:
real = False
break
else:
real = True
eps = S.Zero
if not real:
for h, q in L:
_, h = h.primitive()
eps += RootSum(
q, Lambda(t, t*log(h.as_expr())), quadratic=True)
else:
for h, q in L:
_, h = h.primitive()
R = log_to_real(h, q, x, t)
if R is not None:
eps += R
else:
eps += RootSum(
q, Lambda(t, t*log(h.as_expr())), quadratic=True)
result += eps
return coeff*result
def ratint_ratpart(f, g, x):
"""
Horowitz-Ostrogradsky algorithm.
Explanation
===========
Given a field K and polynomials f and g in K[x], such that f and g
are coprime and deg(f) < deg(g), returns fractions A and B in K(x),
such that f/g = A' + B and B has square-free denominator.
Examples
========
>>> from sympy.integrals.rationaltools import ratint_ratpart
>>> from sympy.abc import x, y
>>> from sympy import Poly
>>> ratint_ratpart(Poly(1, x, domain='ZZ'),
... Poly(x + 1, x, domain='ZZ'), x)
(0, 1/(x + 1))
>>> ratint_ratpart(Poly(1, x, domain='EX'),
... Poly(x**2 + y**2, x, domain='EX'), x)
(0, 1/(x**2 + y**2))
>>> ratint_ratpart(Poly(36, x, domain='ZZ'),
... Poly(x**5 - 2*x**4 - 2*x**3 + 4*x**2 + x - 2, x, domain='ZZ'), x)
((12*x + 6)/(x**2 - 1), 12/(x**2 - x - 2))
See Also
========
ratint, ratint_logpart
"""
from sympy.solvers.solvers import solve
f = Poly(f, x)
g = Poly(g, x)
u, v, _ = g.cofactors(g.diff())
n = u.degree()
m = v.degree()
A_coeffs = [ Dummy('a' + str(n - i)) for i in range(0, n) ]
B_coeffs = [ Dummy('b' + str(m - i)) for i in range(0, m) ]
C_coeffs = A_coeffs + B_coeffs
A = Poly(A_coeffs, x, domain=ZZ[C_coeffs])
B = Poly(B_coeffs, x, domain=ZZ[C_coeffs])
H = f - A.diff()*v + A*(u.diff()*v).quo(u) - B*u
result = solve(H.coeffs(), C_coeffs)
A = A.as_expr().subs(result)
B = B.as_expr().subs(result)
rat_part = cancel(A/u.as_expr(), x)
log_part = cancel(B/v.as_expr(), x)
return rat_part, log_part
def ratint_logpart(f, g, x, t=None):
r"""
Lazard-Rioboo-Trager algorithm.
Explanation
===========
Given a field K and polynomials f and g in K[x], such that f and g
are coprime, deg(f) < deg(g) and g is square-free, returns a list
of tuples (s_i, q_i) of polynomials, for i = 1..n, such that s_i
in K[t, x] and q_i in K[t], and::
___ ___
d f d \ ` \ `
-- - = -- ) ) a log(s_i(a, x))
dx g dx /__, /__,
i=1..n a | q_i(a) = 0
Examples
========
>>> from sympy.integrals.rationaltools import ratint_logpart
>>> from sympy.abc import x
>>> from sympy import Poly
>>> ratint_logpart(Poly(1, x, domain='ZZ'),
... Poly(x**2 + x + 1, x, domain='ZZ'), x)
[(Poly(x + 3*_t/2 + 1/2, x, domain='QQ[_t]'),
...Poly(3*_t**2 + 1, _t, domain='ZZ'))]
>>> ratint_logpart(Poly(12, x, domain='ZZ'),
... Poly(x**2 - x - 2, x, domain='ZZ'), x)
[(Poly(x - 3*_t/8 - 1/2, x, domain='QQ[_t]'),
...Poly(-_t**2 + 16, _t, domain='ZZ'))]
See Also
========
ratint, ratint_ratpart
"""
f, g = Poly(f, x), Poly(g, x)
t = t or Dummy('t')
a, b = g, f - g.diff()*Poly(t, x)
res, R = resultant(a, b, includePRS=True)
res = Poly(res, t, composite=False)
assert res, "BUG: resultant(%s, %s) cannot be zero" % (a, b)
R_map, H = {}, []
for r in R:
R_map[r.degree()] = r
def _include_sign(c, sqf):
if c.is_extended_real and (c < 0) == True:
h, k = sqf[0]
c_poly = c.as_poly(h.gens)
sqf[0] = h*c_poly, k
C, res_sqf = res.sqf_list()
_include_sign(C, res_sqf)
for q, i in res_sqf:
_, q = q.primitive()
if g.degree() == i:
H.append((g, q))
else:
h = R_map[i]
h_lc = Poly(h.LC(), t, field=True)
c, h_lc_sqf = h_lc.sqf_list(all=True)
_include_sign(c, h_lc_sqf)
for a, j in h_lc_sqf:
h = h.quo(Poly(a.gcd(q)**j, x))
inv, coeffs = h_lc.invert(q), [S.One]
for coeff in h.coeffs()[1:]:
coeff = coeff.as_poly(inv.gens)
T = (inv*coeff).rem(q)
coeffs.append(T.as_expr())
h = Poly(dict(list(zip(h.monoms(), coeffs))), x)
H.append((h, q))
return H
def log_to_atan(f, g):
"""
Convert complex logarithms to real arctangents.
Explanation
===========
Given a real field K and polynomials f and g in K[x], with g != 0,
returns a sum h of arctangents of polynomials in K[x], such that:
dh d f + I g
-- = -- I log( ------- )
dx dx f - I g
Examples
========
>>> from sympy.integrals.rationaltools import log_to_atan
>>> from sympy.abc import x
>>> from sympy import Poly, sqrt, S
>>> log_to_atan(Poly(x, x, domain='ZZ'), Poly(1, x, domain='ZZ'))
2*atan(x)
>>> log_to_atan(Poly(x + S(1)/2, x, domain='QQ'),
... Poly(sqrt(3)/2, x, domain='EX'))
2*atan(2*sqrt(3)*x/3 + sqrt(3)/3)
See Also
========
log_to_real
"""
if f.degree() < g.degree():
f, g = -g, f
f = f.to_field()
g = g.to_field()
p, q = f.div(g)
if q.is_zero:
return 2*atan(p.as_expr())
else:
s, t, h = g.gcdex(-f)
u = (f*s + g*t).quo(h)
A = 2*atan(u.as_expr())
return A + log_to_atan(s, t)
def log_to_real(h, q, x, t):
r"""
Convert complex logarithms to real functions.
Explanation
===========
Given real field K and polynomials h in K[t,x] and q in K[t],
returns real function f such that:
___
df d \ `
-- = -- ) a log(h(a, x))
dx dx /__,
a | q(a) = 0
Examples
========
>>> from sympy.integrals.rationaltools import log_to_real
>>> from sympy.abc import x, y
>>> from sympy import Poly, S
>>> log_to_real(Poly(x + 3*y/2 + S(1)/2, x, domain='QQ[y]'),
... Poly(3*y**2 + 1, y, domain='ZZ'), x, y)
2*sqrt(3)*atan(2*sqrt(3)*x/3 + sqrt(3)/3)/3
>>> log_to_real(Poly(x**2 - 1, x, domain='ZZ'),
... Poly(-2*y + 1, y, domain='ZZ'), x, y)
log(x**2 - 1)/2
See Also
========
log_to_atan
"""
from sympy.simplify.radsimp import collect
u, v = symbols('u,v', cls=Dummy)
H = h.as_expr().xreplace({t: u + I*v}).expand()
Q = q.as_expr().xreplace({t: u + I*v}).expand()
H_map = collect(H, I, evaluate=False)
Q_map = collect(Q, I, evaluate=False)
a, b = H_map.get(S.One, S.Zero), H_map.get(I, S.Zero)
c, d = Q_map.get(S.One, S.Zero), Q_map.get(I, S.Zero)
R = Poly(resultant(c, d, v), u)
R_u = roots(R, filter='R')
if len(R_u) != R.count_roots():
return None
result = S.Zero
for r_u in R_u.keys():
C = Poly(c.xreplace({u: r_u}), v)
if not C:
# t was split into real and imaginary parts
# and denom Q(u, v) = c + I*d. We just found
# that c(r_u) is 0 so the roots are in d
C = Poly(d.xreplace({u: r_u}), v)
# we were going to reject roots from C that
# did not set d to zero, but since we are now
# using C = d and c is already 0, there is
# nothing to check
d = S.Zero
R_v = roots(C, filter='R')
if len(R_v) != C.count_roots():
return None
R_v_paired = [] # take one from each pair of conjugate roots
for r_v in R_v:
if r_v not in R_v_paired and -r_v not in R_v_paired:
if r_v.is_negative or r_v.could_extract_minus_sign():
R_v_paired.append(-r_v)
elif not r_v.is_zero:
R_v_paired.append(r_v)
for r_v in R_v_paired:
D = d.xreplace({u: r_u, v: r_v})
if D.evalf(chop=True) != 0:
continue
A = Poly(a.xreplace({u: r_u, v: r_v}), x)
B = Poly(b.xreplace({u: r_u, v: r_v}), x)
AB = (A**2 + B**2).as_expr()
result += r_u*log(AB) + r_v*log_to_atan(A, B)
R_q = roots(q, filter='R')
if len(R_q) != q.count_roots():
return None
for r in R_q.keys():
result += r*log(h.as_expr().subs(t, r))
return result
PK ]ZZZ��0�j �j sympy/integrals/rde.py"""
Algorithms for solving the Risch differential equation.
Given a differential field K of characteristic 0 that is a simple
monomial extension of a base field k and f, g in K, the Risch
Differential Equation problem is to decide if there exist y in K such
that Dy + f*y == g and to find one if there are some. If t is a
monomial over k and the coefficients of f and g are in k(t), then y is
in k(t), and the outline of the algorithm here is given as:
1. Compute the normal part n of the denominator of y. The problem is
then reduced to finding y' in k<t>, where y == y'/n.
2. Compute the special part s of the denominator of y. The problem is
then reduced to finding y'' in k[t], where y == y''/(n*s)
3. Bound the degree of y''.
4. Reduce the equation Dy + f*y == g to a similar equation with f, g in
k[t].
5. Find the solutions in k[t] of bounded degree of the reduced equation.
See Chapter 6 of "Symbolic Integration I: Transcendental Functions" by
Manuel Bronstein. See also the docstring of risch.py.
"""
from operator import mul
from functools import reduce
from sympy.core import oo
from sympy.core.symbol import Dummy
from sympy.polys import Poly, gcd, ZZ, cancel
from sympy.functions.elementary.complexes import (im, re)
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.integrals.risch import (gcdex_diophantine, frac_in, derivation,
splitfactor, NonElementaryIntegralException, DecrementLevel, recognize_log_derivative)
# TODO: Add messages to NonElementaryIntegralException errors
def order_at(a, p, t):
"""
Computes the order of a at p, with respect to t.
Explanation
===========
For a, p in k[t], the order of a at p is defined as nu_p(a) = max({n
in Z+ such that p**n|a}), where a != 0. If a == 0, nu_p(a) = +oo.
To compute the order at a rational function, a/b, use the fact that
nu_p(a/b) == nu_p(a) - nu_p(b).
"""
if a.is_zero:
return oo
if p == Poly(t, t):
return a.as_poly(t).ET()[0][0]
# Uses binary search for calculating the power. power_list collects the tuples
# (p^k,k) where each k is some power of 2. After deciding the largest k
# such that k is power of 2 and p^k|a the loop iteratively calculates
# the actual power.
power_list = []
p1 = p
r = a.rem(p1)
tracks_power = 1
while r.is_zero:
power_list.append((p1,tracks_power))
p1 = p1*p1
tracks_power *= 2
r = a.rem(p1)
n = 0
product = Poly(1, t)
while len(power_list) != 0:
final = power_list.pop()
productf = product*final[0]
r = a.rem(productf)
if r.is_zero:
n += final[1]
product = productf
return n
def order_at_oo(a, d, t):
"""
Computes the order of a/d at oo (infinity), with respect to t.
For f in k(t), the order or f at oo is defined as deg(d) - deg(a), where
f == a/d.
"""
if a.is_zero:
return oo
return d.degree(t) - a.degree(t)
def weak_normalizer(a, d, DE, z=None):
"""
Weak normalization.
Explanation
===========
Given a derivation D on k[t] and f == a/d in k(t), return q in k[t]
such that f - Dq/q is weakly normalized with respect to t.
f in k(t) is said to be "weakly normalized" with respect to t if
residue_p(f) is not a positive integer for any normal irreducible p
in k[t] such that f is in R_p (Definition 6.1.1). If f has an
elementary integral, this is equivalent to no logarithm of
integral(f) whose argument depends on t has a positive integer
coefficient, where the arguments of the logarithms not in k(t) are
in k[t].
Returns (q, f - Dq/q)
"""
z = z or Dummy('z')
dn, ds = splitfactor(d, DE)
# Compute d1, where dn == d1*d2**2*...*dn**n is a square-free
# factorization of d.
g = gcd(dn, dn.diff(DE.t))
d_sqf_part = dn.quo(g)
d1 = d_sqf_part.quo(gcd(d_sqf_part, g))
a1, b = gcdex_diophantine(d.quo(d1).as_poly(DE.t), d1.as_poly(DE.t),
a.as_poly(DE.t))
r = (a - Poly(z, DE.t)*derivation(d1, DE)).as_poly(DE.t).resultant(
d1.as_poly(DE.t))
r = Poly(r, z)
if not r.expr.has(z):
return (Poly(1, DE.t), (a, d))
N = [i for i in r.real_roots() if i in ZZ and i > 0]
q = reduce(mul, [gcd(a - Poly(n, DE.t)*derivation(d1, DE), d1) for n in N],
Poly(1, DE.t))
dq = derivation(q, DE)
sn = q*a - d*dq
sd = q*d
sn, sd = sn.cancel(sd, include=True)
return (q, (sn, sd))
def normal_denom(fa, fd, ga, gd, DE):
"""
Normal part of the denominator.
Explanation
===========
Given a derivation D on k[t] and f, g in k(t) with f weakly
normalized with respect to t, either raise NonElementaryIntegralException,
in which case the equation Dy + f*y == g has no solution in k(t), or the
quadruplet (a, b, c, h) such that a, h in k[t], b, c in k<t>, and for any
solution y in k(t) of Dy + f*y == g, q = y*h in k<t> satisfies
a*Dq + b*q == c.
This constitutes step 1 in the outline given in the rde.py docstring.
"""
dn, ds = splitfactor(fd, DE)
en, es = splitfactor(gd, DE)
p = dn.gcd(en)
h = en.gcd(en.diff(DE.t)).quo(p.gcd(p.diff(DE.t)))
a = dn*h
c = a*h
if c.div(en)[1]:
# en does not divide dn*h**2
raise NonElementaryIntegralException
ca = c*ga
ca, cd = ca.cancel(gd, include=True)
ba = a*fa - dn*derivation(h, DE)*fd
ba, bd = ba.cancel(fd, include=True)
# (dn*h, dn*h*f - dn*Dh, dn*h**2*g, h)
return (a, (ba, bd), (ca, cd), h)
def special_denom(a, ba, bd, ca, cd, DE, case='auto'):
"""
Special part of the denominator.
Explanation
===========
case is one of {'exp', 'tan', 'primitive'} for the hyperexponential,
hypertangent, and primitive cases, respectively. For the
hyperexponential (resp. hypertangent) case, given a derivation D on
k[t] and a in k[t], b, c, in k<t> with Dt/t in k (resp. Dt/(t**2 + 1) in
k, sqrt(-1) not in k), a != 0, and gcd(a, t) == 1 (resp.
gcd(a, t**2 + 1) == 1), return the quadruplet (A, B, C, 1/h) such that
A, B, C, h in k[t] and for any solution q in k<t> of a*Dq + b*q == c,
r = qh in k[t] satisfies A*Dr + B*r == C.
For ``case == 'primitive'``, k<t> == k[t], so it returns (a, b, c, 1) in
this case.
This constitutes step 2 of the outline given in the rde.py docstring.
"""
# TODO: finish writing this and write tests
if case == 'auto':
case = DE.case
if case == 'exp':
p = Poly(DE.t, DE.t)
elif case == 'tan':
p = Poly(DE.t**2 + 1, DE.t)
elif case in ('primitive', 'base'):
B = ba.to_field().quo(bd)
C = ca.to_field().quo(cd)
return (a, B, C, Poly(1, DE.t))
else:
raise ValueError("case must be one of {'exp', 'tan', 'primitive', "
"'base'}, not %s." % case)
nb = order_at(ba, p, DE.t) - order_at(bd, p, DE.t)
nc = order_at(ca, p, DE.t) - order_at(cd, p, DE.t)
n = min(0, nc - min(0, nb))
if not nb:
# Possible cancellation.
from .prde import parametric_log_deriv
if case == 'exp':
dcoeff = DE.d.quo(Poly(DE.t, DE.t))
with DecrementLevel(DE): # We are guaranteed to not have problems,
# because case != 'base'.
alphaa, alphad = frac_in(-ba.eval(0)/bd.eval(0)/a.eval(0), DE.t)
etaa, etad = frac_in(dcoeff, DE.t)
A = parametric_log_deriv(alphaa, alphad, etaa, etad, DE)
if A is not None:
Q, m, z = A
if Q == 1:
n = min(n, m)
elif case == 'tan':
dcoeff = DE.d.quo(Poly(DE.t**2+1, DE.t))
with DecrementLevel(DE): # We are guaranteed to not have problems,
# because case != 'base'.
alphaa, alphad = frac_in(im(-ba.eval(sqrt(-1))/bd.eval(sqrt(-1))/a.eval(sqrt(-1))), DE.t)
betaa, betad = frac_in(re(-ba.eval(sqrt(-1))/bd.eval(sqrt(-1))/a.eval(sqrt(-1))), DE.t)
etaa, etad = frac_in(dcoeff, DE.t)
if recognize_log_derivative(Poly(2, DE.t)*betaa, betad, DE):
A = parametric_log_deriv(alphaa*Poly(sqrt(-1), DE.t)*betad+alphad*betaa, alphad*betad, etaa, etad, DE)
if A is not None:
Q, m, z = A
if Q == 1:
n = min(n, m)
N = max(0, -nb, n - nc)
pN = p**N
pn = p**-n
A = a*pN
B = ba*pN.quo(bd) + Poly(n, DE.t)*a*derivation(p, DE).quo(p)*pN
C = (ca*pN*pn).quo(cd)
h = pn
# (a*p**N, (b + n*a*Dp/p)*p**N, c*p**(N - n), p**-n)
return (A, B, C, h)
def bound_degree(a, b, cQ, DE, case='auto', parametric=False):
"""
Bound on polynomial solutions.
Explanation
===========
Given a derivation D on k[t] and ``a``, ``b``, ``c`` in k[t] with ``a != 0``, return
n in ZZ such that deg(q) <= n for any solution q in k[t] of
a*Dq + b*q == c, when parametric=False, or deg(q) <= n for any solution
c1, ..., cm in Const(k) and q in k[t] of a*Dq + b*q == Sum(ci*gi, (i, 1, m))
when parametric=True.
For ``parametric=False``, ``cQ`` is ``c``, a ``Poly``; for ``parametric=True``, ``cQ`` is Q ==
[q1, ..., qm], a list of Polys.
This constitutes step 3 of the outline given in the rde.py docstring.
"""
# TODO: finish writing this and write tests
if case == 'auto':
case = DE.case
da = a.degree(DE.t)
db = b.degree(DE.t)
# The parametric and regular cases are identical, except for this part
if parametric:
dc = max(i.degree(DE.t) for i in cQ)
else:
dc = cQ.degree(DE.t)
alpha = cancel(-b.as_poly(DE.t).LC().as_expr()/
a.as_poly(DE.t).LC().as_expr())
if case == 'base':
n = max(0, dc - max(db, da - 1))
if db == da - 1 and alpha.is_Integer:
n = max(0, alpha, dc - db)
elif case == 'primitive':
if db > da:
n = max(0, dc - db)
else:
n = max(0, dc - da + 1)
etaa, etad = frac_in(DE.d, DE.T[DE.level - 1])
t1 = DE.t
with DecrementLevel(DE):
alphaa, alphad = frac_in(alpha, DE.t)
if db == da - 1:
from .prde import limited_integrate
# if alpha == m*Dt + Dz for z in k and m in ZZ:
try:
(za, zd), m = limited_integrate(alphaa, alphad, [(etaa, etad)],
DE)
except NonElementaryIntegralException:
pass
else:
if len(m) != 1:
raise ValueError("Length of m should be 1")
n = max(n, m[0])
elif db == da:
# if alpha == Dz/z for z in k*:
# beta = -lc(a*Dz + b*z)/(z*lc(a))
# if beta == m*Dt + Dw for w in k and m in ZZ:
# n = max(n, m)
from .prde import is_log_deriv_k_t_radical_in_field
A = is_log_deriv_k_t_radical_in_field(alphaa, alphad, DE)
if A is not None:
aa, z = A
if aa == 1:
beta = -(a*derivation(z, DE).as_poly(t1) +
b*z.as_poly(t1)).LC()/(z.as_expr()*a.LC())
betaa, betad = frac_in(beta, DE.t)
from .prde import limited_integrate
try:
(za, zd), m = limited_integrate(betaa, betad,
[(etaa, etad)], DE)
except NonElementaryIntegralException:
pass
else:
if len(m) != 1:
raise ValueError("Length of m should be 1")
n = max(n, m[0].as_expr())
elif case == 'exp':
from .prde import parametric_log_deriv
n = max(0, dc - max(db, da))
if da == db:
etaa, etad = frac_in(DE.d.quo(Poly(DE.t, DE.t)), DE.T[DE.level - 1])
with DecrementLevel(DE):
alphaa, alphad = frac_in(alpha, DE.t)
A = parametric_log_deriv(alphaa, alphad, etaa, etad, DE)
if A is not None:
# if alpha == m*Dt/t + Dz/z for z in k* and m in ZZ:
# n = max(n, m)
a, m, z = A
if a == 1:
n = max(n, m)
elif case in ('tan', 'other_nonlinear'):
delta = DE.d.degree(DE.t)
lam = DE.d.LC()
alpha = cancel(alpha/lam)
n = max(0, dc - max(da + delta - 1, db))
if db == da + delta - 1 and alpha.is_Integer:
n = max(0, alpha, dc - db)
else:
raise ValueError("case must be one of {'exp', 'tan', 'primitive', "
"'other_nonlinear', 'base'}, not %s." % case)
return n
def spde(a, b, c, n, DE):
"""
Rothstein's Special Polynomial Differential Equation algorithm.
Explanation
===========
Given a derivation D on k[t], an integer n and ``a``,``b``,``c`` in k[t] with
``a != 0``, either raise NonElementaryIntegralException, in which case the
equation a*Dq + b*q == c has no solution of degree at most ``n`` in
k[t], or return the tuple (B, C, m, alpha, beta) such that B, C,
alpha, beta in k[t], m in ZZ, and any solution q in k[t] of degree
at most n of a*Dq + b*q == c must be of the form
q == alpha*h + beta, where h in k[t], deg(h) <= m, and Dh + B*h == C.
This constitutes step 4 of the outline given in the rde.py docstring.
"""
zero = Poly(0, DE.t)
alpha = Poly(1, DE.t)
beta = Poly(0, DE.t)
while True:
if c.is_zero:
return (zero, zero, 0, zero, beta) # -1 is more to the point
if (n < 0) is True:
raise NonElementaryIntegralException
g = a.gcd(b)
if not c.rem(g).is_zero: # g does not divide c
raise NonElementaryIntegralException
a, b, c = a.quo(g), b.quo(g), c.quo(g)
if a.degree(DE.t) == 0:
b = b.to_field().quo(a)
c = c.to_field().quo(a)
return (b, c, n, alpha, beta)
r, z = gcdex_diophantine(b, a, c)
b += derivation(a, DE)
c = z - derivation(r, DE)
n -= a.degree(DE.t)
beta += alpha * r
alpha *= a
def no_cancel_b_large(b, c, n, DE):
"""
Poly Risch Differential Equation - No cancellation: deg(b) large enough.
Explanation
===========
Given a derivation D on k[t], ``n`` either an integer or +oo, and ``b``,``c``
in k[t] with ``b != 0`` and either D == d/dt or
deg(b) > max(0, deg(D) - 1), either raise NonElementaryIntegralException, in
which case the equation ``Dq + b*q == c`` has no solution of degree at
most n in k[t], or a solution q in k[t] of this equation with
``deg(q) < n``.
"""
q = Poly(0, DE.t)
while not c.is_zero:
m = c.degree(DE.t) - b.degree(DE.t)
if not 0 <= m <= n: # n < 0 or m < 0 or m > n
raise NonElementaryIntegralException
p = Poly(c.as_poly(DE.t).LC()/b.as_poly(DE.t).LC()*DE.t**m, DE.t,
expand=False)
q = q + p
n = m - 1
c = c - derivation(p, DE) - b*p
return q
def no_cancel_b_small(b, c, n, DE):
"""
Poly Risch Differential Equation - No cancellation: deg(b) small enough.
Explanation
===========
Given a derivation D on k[t], ``n`` either an integer or +oo, and ``b``,``c``
in k[t] with deg(b) < deg(D) - 1 and either D == d/dt or
deg(D) >= 2, either raise NonElementaryIntegralException, in which case the
equation Dq + b*q == c has no solution of degree at most n in k[t],
or a solution q in k[t] of this equation with deg(q) <= n, or the
tuple (h, b0, c0) such that h in k[t], b0, c0, in k, and for any
solution q in k[t] of degree at most n of Dq + bq == c, y == q - h
is a solution in k of Dy + b0*y == c0.
"""
q = Poly(0, DE.t)
while not c.is_zero:
if n == 0:
m = 0
else:
m = c.degree(DE.t) - DE.d.degree(DE.t) + 1
if not 0 <= m <= n: # n < 0 or m < 0 or m > n
raise NonElementaryIntegralException
if m > 0:
p = Poly(c.as_poly(DE.t).LC()/(m*DE.d.as_poly(DE.t).LC())*DE.t**m,
DE.t, expand=False)
else:
if b.degree(DE.t) != c.degree(DE.t):
raise NonElementaryIntegralException
if b.degree(DE.t) == 0:
return (q, b.as_poly(DE.T[DE.level - 1]),
c.as_poly(DE.T[DE.level - 1]))
p = Poly(c.as_poly(DE.t).LC()/b.as_poly(DE.t).LC(), DE.t,
expand=False)
q = q + p
n = m - 1
c = c - derivation(p, DE) - b*p
return q
# TODO: better name for this function
def no_cancel_equal(b, c, n, DE):
"""
Poly Risch Differential Equation - No cancellation: deg(b) == deg(D) - 1
Explanation
===========
Given a derivation D on k[t] with deg(D) >= 2, n either an integer
or +oo, and b, c in k[t] with deg(b) == deg(D) - 1, either raise
NonElementaryIntegralException, in which case the equation Dq + b*q == c has
no solution of degree at most n in k[t], or a solution q in k[t] of
this equation with deg(q) <= n, or the tuple (h, m, C) such that h
in k[t], m in ZZ, and C in k[t], and for any solution q in k[t] of
degree at most n of Dq + b*q == c, y == q - h is a solution in k[t]
of degree at most m of Dy + b*y == C.
"""
q = Poly(0, DE.t)
lc = cancel(-b.as_poly(DE.t).LC()/DE.d.as_poly(DE.t).LC())
if lc.is_Integer and lc.is_positive:
M = lc
else:
M = -1
while not c.is_zero:
m = max(M, c.degree(DE.t) - DE.d.degree(DE.t) + 1)
if not 0 <= m <= n: # n < 0 or m < 0 or m > n
raise NonElementaryIntegralException
u = cancel(m*DE.d.as_poly(DE.t).LC() + b.as_poly(DE.t).LC())
if u.is_zero:
return (q, m, c)
if m > 0:
p = Poly(c.as_poly(DE.t).LC()/u*DE.t**m, DE.t, expand=False)
else:
if c.degree(DE.t) != DE.d.degree(DE.t) - 1:
raise NonElementaryIntegralException
else:
p = c.as_poly(DE.t).LC()/b.as_poly(DE.t).LC()
q = q + p
n = m - 1
c = c - derivation(p, DE) - b*p
return q
def cancel_primitive(b, c, n, DE):
"""
Poly Risch Differential Equation - Cancellation: Primitive case.
Explanation
===========
Given a derivation D on k[t], n either an integer or +oo, ``b`` in k, and
``c`` in k[t] with Dt in k and ``b != 0``, either raise
NonElementaryIntegralException, in which case the equation Dq + b*q == c
has no solution of degree at most n in k[t], or a solution q in k[t] of
this equation with deg(q) <= n.
"""
# Delayed imports
from .prde import is_log_deriv_k_t_radical_in_field
with DecrementLevel(DE):
ba, bd = frac_in(b, DE.t)
A = is_log_deriv_k_t_radical_in_field(ba, bd, DE)
if A is not None:
n, z = A
if n == 1: # b == Dz/z
raise NotImplementedError("is_deriv_in_field() is required to "
" solve this problem.")
# if z*c == Dp for p in k[t] and deg(p) <= n:
# return p/z
# else:
# raise NonElementaryIntegralException
if c.is_zero:
return c # return 0
if n < c.degree(DE.t):
raise NonElementaryIntegralException
q = Poly(0, DE.t)
while not c.is_zero:
m = c.degree(DE.t)
if n < m:
raise NonElementaryIntegralException
with DecrementLevel(DE):
a2a, a2d = frac_in(c.LC(), DE.t)
sa, sd = rischDE(ba, bd, a2a, a2d, DE)
stm = Poly(sa.as_expr()/sd.as_expr()*DE.t**m, DE.t, expand=False)
q += stm
n = m - 1
c -= b*stm + derivation(stm, DE)
return q
def cancel_exp(b, c, n, DE):
"""
Poly Risch Differential Equation - Cancellation: Hyperexponential case.
Explanation
===========
Given a derivation D on k[t], n either an integer or +oo, ``b`` in k, and
``c`` in k[t] with Dt/t in k and ``b != 0``, either raise
NonElementaryIntegralException, in which case the equation Dq + b*q == c
has no solution of degree at most n in k[t], or a solution q in k[t] of
this equation with deg(q) <= n.
"""
from .prde import parametric_log_deriv
eta = DE.d.quo(Poly(DE.t, DE.t)).as_expr()
with DecrementLevel(DE):
etaa, etad = frac_in(eta, DE.t)
ba, bd = frac_in(b, DE.t)
A = parametric_log_deriv(ba, bd, etaa, etad, DE)
if A is not None:
a, m, z = A
if a == 1:
raise NotImplementedError("is_deriv_in_field() is required to "
"solve this problem.")
# if c*z*t**m == Dp for p in k<t> and q = p/(z*t**m) in k[t] and
# deg(q) <= n:
# return q
# else:
# raise NonElementaryIntegralException
if c.is_zero:
return c # return 0
if n < c.degree(DE.t):
raise NonElementaryIntegralException
q = Poly(0, DE.t)
while not c.is_zero:
m = c.degree(DE.t)
if n < m:
raise NonElementaryIntegralException
# a1 = b + m*Dt/t
a1 = b.as_expr()
with DecrementLevel(DE):
# TODO: Write a dummy function that does this idiom
a1a, a1d = frac_in(a1, DE.t)
a1a = a1a*etad + etaa*a1d*Poly(m, DE.t)
a1d = a1d*etad
a2a, a2d = frac_in(c.LC(), DE.t)
sa, sd = rischDE(a1a, a1d, a2a, a2d, DE)
stm = Poly(sa.as_expr()/sd.as_expr()*DE.t**m, DE.t, expand=False)
q += stm
n = m - 1
c -= b*stm + derivation(stm, DE) # deg(c) becomes smaller
return q
def solve_poly_rde(b, cQ, n, DE, parametric=False):
"""
Solve a Polynomial Risch Differential Equation with degree bound ``n``.
This constitutes step 4 of the outline given in the rde.py docstring.
For parametric=False, cQ is c, a Poly; for parametric=True, cQ is Q ==
[q1, ..., qm], a list of Polys.
"""
# No cancellation
if not b.is_zero and (DE.case == 'base' or
b.degree(DE.t) > max(0, DE.d.degree(DE.t) - 1)):
if parametric:
# Delayed imports
from .prde import prde_no_cancel_b_large
return prde_no_cancel_b_large(b, cQ, n, DE)
return no_cancel_b_large(b, cQ, n, DE)
elif (b.is_zero or b.degree(DE.t) < DE.d.degree(DE.t) - 1) and \
(DE.case == 'base' or DE.d.degree(DE.t) >= 2):
if parametric:
from .prde import prde_no_cancel_b_small
return prde_no_cancel_b_small(b, cQ, n, DE)
R = no_cancel_b_small(b, cQ, n, DE)
if isinstance(R, Poly):
return R
else:
# XXX: Might k be a field? (pg. 209)
h, b0, c0 = R
with DecrementLevel(DE):
b0, c0 = b0.as_poly(DE.t), c0.as_poly(DE.t)
if b0 is None: # See above comment
raise ValueError("b0 should be a non-Null value")
if c0 is None:
raise ValueError("c0 should be a non-Null value")
y = solve_poly_rde(b0, c0, n, DE).as_poly(DE.t)
return h + y
elif DE.d.degree(DE.t) >= 2 and b.degree(DE.t) == DE.d.degree(DE.t) - 1 and \
n > -b.as_poly(DE.t).LC()/DE.d.as_poly(DE.t).LC():
# TODO: Is this check necessary, and if so, what should it do if it fails?
# b comes from the first element returned from spde()
if not b.as_poly(DE.t).LC().is_number:
raise TypeError("Result should be a number")
if parametric:
raise NotImplementedError("prde_no_cancel_b_equal() is not yet "
"implemented.")
R = no_cancel_equal(b, cQ, n, DE)
if isinstance(R, Poly):
return R
else:
h, m, C = R
# XXX: Or should it be rischDE()?
y = solve_poly_rde(b, C, m, DE)
return h + y
else:
# Cancellation
if b.is_zero:
raise NotImplementedError("Remaining cases for Poly (P)RDE are "
"not yet implemented (is_deriv_in_field() required).")
else:
if DE.case == 'exp':
if parametric:
raise NotImplementedError("Parametric RDE cancellation "
"hyperexponential case is not yet implemented.")
return cancel_exp(b, cQ, n, DE)
elif DE.case == 'primitive':
if parametric:
raise NotImplementedError("Parametric RDE cancellation "
"primitive case is not yet implemented.")
return cancel_primitive(b, cQ, n, DE)
else:
raise NotImplementedError("Other Poly (P)RDE cancellation "
"cases are not yet implemented (%s)." % DE.case)
if parametric:
raise NotImplementedError("Remaining cases for Poly PRDE not yet "
"implemented.")
raise NotImplementedError("Remaining cases for Poly RDE not yet "
"implemented.")
def rischDE(fa, fd, ga, gd, DE):
"""
Solve a Risch Differential Equation: Dy + f*y == g.
Explanation
===========
See the outline in the docstring of rde.py for more information
about the procedure used. Either raise NonElementaryIntegralException, in
which case there is no solution y in the given differential field,
or return y in k(t) satisfying Dy + f*y == g, or raise
NotImplementedError, in which case, the algorithms necessary to
solve the given Risch Differential Equation have not yet been
implemented.
"""
_, (fa, fd) = weak_normalizer(fa, fd, DE)
a, (ba, bd), (ca, cd), hn = normal_denom(fa, fd, ga, gd, DE)
A, B, C, hs = special_denom(a, ba, bd, ca, cd, DE)
try:
# Until this is fully implemented, use oo. Note that this will almost
# certainly cause non-termination in spde() (unless A == 1), and
# *might* lead to non-termination in the next step for a nonelementary
# integral (I don't know for certain yet). Fortunately, spde() is
# currently written recursively, so this will just give
# RuntimeError: maximum recursion depth exceeded.
n = bound_degree(A, B, C, DE)
except NotImplementedError:
# Useful for debugging:
# import warnings
# warnings.warn("rischDE: Proceeding with n = oo; may cause "
# "non-termination.")
n = oo
B, C, m, alpha, beta = spde(A, B, C, n, DE)
if C.is_zero:
y = C
else:
y = solve_poly_rde(B, C, m, DE)
return (alpha*y + beta, hn*hs)
PK ]ZZZث/ sympy/integrals/risch.py"""
The Risch Algorithm for transcendental function integration.
The core algorithms for the Risch algorithm are here. The subproblem
algorithms are in the rde.py and prde.py files for the Risch
Differential Equation solver and the parametric problems solvers,
respectively. All important information concerning the differential extension
for an integrand is stored in a DifferentialExtension object, which in the code
is usually called DE. Throughout the code and Inside the DifferentialExtension
object, the conventions/attribute names are that the base domain is QQ and each
differential extension is x, t0, t1, ..., tn-1 = DE.t. DE.x is the variable of
integration (Dx == 1), DE.D is a list of the derivatives of
x, t1, t2, ..., tn-1 = t, DE.T is the list [x, t1, t2, ..., tn-1], DE.t is the
outer-most variable of the differential extension at the given level (the level
can be adjusted using DE.increment_level() and DE.decrement_level()),
k is the field C(x, t0, ..., tn-2), where C is the constant field. The
numerator of a fraction is denoted by a and the denominator by
d. If the fraction is named f, fa == numer(f) and fd == denom(f).
Fractions are returned as tuples (fa, fd). DE.d and DE.t are used to
represent the topmost derivation and extension variable, respectively.
The docstring of a function signifies whether an argument is in k[t], in
which case it will just return a Poly in t, or in k(t), in which case it
will return the fraction (fa, fd). Other variable names probably come
from the names used in Bronstein's book.
"""
from types import GeneratorType
from functools import reduce
from sympy.core.function import Lambda
from sympy.core.mul import Mul
from sympy.core.intfunc import ilcm
from sympy.core.numbers import I
from sympy.core.power import Pow
from sympy.core.relational import Ne
from sympy.core.singleton import S
from sympy.core.sorting import ordered, default_sort_key
from sympy.core.symbol import Dummy, Symbol
from sympy.functions.elementary.exponential import log, exp
from sympy.functions.elementary.hyperbolic import (cosh, coth, sinh,
tanh)
from sympy.functions.elementary.piecewise import Piecewise
from sympy.functions.elementary.trigonometric import (atan, sin, cos,
tan, acot, cot, asin, acos)
from .integrals import integrate, Integral
from .heurisch import _symbols
from sympy.polys.polyerrors import PolynomialError
from sympy.polys.polytools import (real_roots, cancel, Poly, gcd,
reduced)
from sympy.polys.rootoftools import RootSum
from sympy.utilities.iterables import numbered_symbols
def integer_powers(exprs):
"""
Rewrites a list of expressions as integer multiples of each other.
Explanation
===========
For example, if you have [x, x/2, x**2 + 1, 2*x/3], then you can rewrite
this as [(x/6) * 6, (x/6) * 3, (x**2 + 1) * 1, (x/6) * 4]. This is useful
in the Risch integration algorithm, where we must write exp(x) + exp(x/2)
as (exp(x/2))**2 + exp(x/2), but not as exp(x) + sqrt(exp(x)) (this is
because only the transcendental case is implemented and we therefore cannot
integrate algebraic extensions). The integer multiples returned by this
function for each term are the smallest possible (their content equals 1).
Returns a list of tuples where the first element is the base term and the
second element is a list of `(item, factor)` terms, where `factor` is the
integer multiplicative factor that must multiply the base term to obtain
the original item.
The easiest way to understand this is to look at an example:
>>> from sympy.abc import x
>>> from sympy.integrals.risch import integer_powers
>>> integer_powers([x, x/2, x**2 + 1, 2*x/3])
[(x/6, [(x, 6), (x/2, 3), (2*x/3, 4)]), (x**2 + 1, [(x**2 + 1, 1)])]
We can see how this relates to the example at the beginning of the
docstring. It chose x/6 as the first base term. Then, x can be written as
(x/2) * 2, so we get (0, 2), and so on. Now only element (x**2 + 1)
remains, and there are no other terms that can be written as a rational
multiple of that, so we get that it can be written as (x**2 + 1) * 1.
"""
# Here is the strategy:
# First, go through each term and determine if it can be rewritten as a
# rational multiple of any of the terms gathered so far.
# cancel(a/b).is_Rational is sufficient for this. If it is a multiple, we
# add its multiple to the dictionary.
terms = {}
for term in exprs:
for trm, trm_list in terms.items():
a = cancel(term/trm)
if a.is_Rational:
trm_list.append((term, a))
break
else:
terms[term] = [(term, S.One)]
# After we have done this, we have all the like terms together, so we just
# need to find a common denominator so that we can get the base term and
# integer multiples such that each term can be written as an integer
# multiple of the base term, and the content of the integers is 1.
newterms = {}
for term, term_list in terms.items():
common_denom = reduce(ilcm, [i.as_numer_denom()[1] for _, i in
term_list])
newterm = term/common_denom
newmults = [(i, j*common_denom) for i, j in term_list]
newterms[newterm] = newmults
return sorted(iter(newterms.items()), key=lambda item: item[0].sort_key())
class DifferentialExtension:
"""
A container for all the information relating to a differential extension.
Explanation
===========
The attributes of this object are (see also the docstring of __init__):
- f: The original (Expr) integrand.
- x: The variable of integration.
- T: List of variables in the extension.
- D: List of derivations in the extension; corresponds to the elements of T.
- fa: Poly of the numerator of the integrand.
- fd: Poly of the denominator of the integrand.
- Tfuncs: Lambda() representations of each element of T (except for x).
For back-substitution after integration.
- backsubs: A (possibly empty) list of further substitutions to be made on
the final integral to make it look more like the integrand.
- exts:
- extargs:
- cases: List of string representations of the cases of T.
- t: The top level extension variable, as defined by the current level
(see level below).
- d: The top level extension derivation, as defined by the current
derivation (see level below).
- case: The string representation of the case of self.d.
(Note that self.T and self.D will always contain the complete extension,
regardless of the level. Therefore, you should ALWAYS use DE.t and DE.d
instead of DE.T[-1] and DE.D[-1]. If you want to have a list of the
derivations or variables only up to the current level, use
DE.D[:len(DE.D) + DE.level + 1] and DE.T[:len(DE.T) + DE.level + 1]. Note
that, in particular, the derivation() function does this.)
The following are also attributes, but will probably not be useful other
than in internal use:
- newf: Expr form of fa/fd.
- level: The number (between -1 and -len(self.T)) such that
self.T[self.level] == self.t and self.D[self.level] == self.d.
Use the methods self.increment_level() and self.decrement_level() to change
the current level.
"""
# __slots__ is defined mainly so we can iterate over all the attributes
# of the class easily (the memory use doesn't matter too much, since we
# only create one DifferentialExtension per integration). Also, it's nice
# to have a safeguard when debugging.
__slots__ = ('f', 'x', 'T', 'D', 'fa', 'fd', 'Tfuncs', 'backsubs',
'exts', 'extargs', 'cases', 'case', 't', 'd', 'newf', 'level',
'ts', 'dummy')
def __init__(self, f=None, x=None, handle_first='log', dummy=False, extension=None, rewrite_complex=None):
"""
Tries to build a transcendental extension tower from ``f`` with respect to ``x``.
Explanation
===========
If it is successful, creates a DifferentialExtension object with, among
others, the attributes fa, fd, D, T, Tfuncs, and backsubs such that
fa and fd are Polys in T[-1] with rational coefficients in T[:-1],
fa/fd == f, and D[i] is a Poly in T[i] with rational coefficients in
T[:i] representing the derivative of T[i] for each i from 1 to len(T).
Tfuncs is a list of Lambda objects for back replacing the functions
after integrating. Lambda() is only used (instead of lambda) to make
them easier to test and debug. Note that Tfuncs corresponds to the
elements of T, except for T[0] == x, but they should be back-substituted
in reverse order. backsubs is a (possibly empty) back-substitution list
that should be applied on the completed integral to make it look more
like the original integrand.
If it is unsuccessful, it raises NotImplementedError.
You can also create an object by manually setting the attributes as a
dictionary to the extension keyword argument. You must include at least
D. Warning, any attribute that is not given will be set to None. The
attributes T, t, d, cases, case, x, and level are set automatically and
do not need to be given. The functions in the Risch Algorithm will NOT
check to see if an attribute is None before using it. This also does not
check to see if the extension is valid (non-algebraic) or even if it is
self-consistent. Therefore, this should only be used for
testing/debugging purposes.
"""
# XXX: If you need to debug this function, set the break point here
if extension:
if 'D' not in extension:
raise ValueError("At least the key D must be included with "
"the extension flag to DifferentialExtension.")
for attr in extension:
setattr(self, attr, extension[attr])
self._auto_attrs()
return
elif f is None or x is None:
raise ValueError("Either both f and x or a manual extension must "
"be given.")
if handle_first not in ('log', 'exp'):
raise ValueError("handle_first must be 'log' or 'exp', not %s." %
str(handle_first))
# f will be the original function, self.f might change if we reset
# (e.g., we pull out a constant from an exponential)
self.f = f
self.x = x
# setting the default value 'dummy'
self.dummy = dummy
self.reset()
exp_new_extension, log_new_extension = True, True
# case of 'automatic' choosing
if rewrite_complex is None:
rewrite_complex = I in self.f.atoms()
if rewrite_complex:
rewritables = {
(sin, cos, cot, tan, sinh, cosh, coth, tanh): exp,
(asin, acos, acot, atan): log,
}
# rewrite the trigonometric components
for candidates, rule in rewritables.items():
self.newf = self.newf.rewrite(candidates, rule)
self.newf = cancel(self.newf)
else:
if any(i.has(x) for i in self.f.atoms(sin, cos, tan, atan, asin, acos)):
raise NotImplementedError("Trigonometric extensions are not "
"supported (yet!)")
exps = set()
pows = set()
numpows = set()
sympows = set()
logs = set()
symlogs = set()
while True:
if self.newf.is_rational_function(*self.T):
break
if not exp_new_extension and not log_new_extension:
# We couldn't find a new extension on the last pass, so I guess
# we can't do it.
raise NotImplementedError("Couldn't find an elementary "
"transcendental extension for %s. Try using a " % str(f) +
"manual extension with the extension flag.")
exps, pows, numpows, sympows, log_new_extension = \
self._rewrite_exps_pows(exps, pows, numpows, sympows, log_new_extension)
logs, symlogs = self._rewrite_logs(logs, symlogs)
if handle_first == 'exp' or not log_new_extension:
exp_new_extension = self._exp_part(exps)
if exp_new_extension is None:
# reset and restart
self.f = self.newf
self.reset()
exp_new_extension = True
continue
if handle_first == 'log' or not exp_new_extension:
log_new_extension = self._log_part(logs)
self.fa, self.fd = frac_in(self.newf, self.t)
self._auto_attrs()
return
def __getattr__(self, attr):
# Avoid AttributeErrors when debugging
if attr not in self.__slots__:
raise AttributeError("%s has no attribute %s" % (repr(self), repr(attr)))
return None
def _rewrite_exps_pows(self, exps, pows, numpows,
sympows, log_new_extension):
"""
Rewrite exps/pows for better processing.
"""
from .prde import is_deriv_k
# Pre-preparsing.
#################
# Get all exp arguments, so we can avoid ahead of time doing
# something like t1 = exp(x), t2 = exp(x/2) == sqrt(t1).
# Things like sqrt(exp(x)) do not automatically simplify to
# exp(x/2), so they will be viewed as algebraic. The easiest way
# to handle this is to convert all instances of exp(a)**Rational
# to exp(Rational*a) before doing anything else. Note that the
# _exp_part code can generate terms of this form, so we do need to
# do this at each pass (or else modify it to not do that).
ratpows = [i for i in self.newf.atoms(Pow)
if (isinstance(i.base, exp) and i.exp.is_Rational)]
ratpows_repl = [
(i, i.base.base**(i.exp*i.base.exp)) for i in ratpows]
self.backsubs += [(j, i) for i, j in ratpows_repl]
self.newf = self.newf.xreplace(dict(ratpows_repl))
# To make the process deterministic, the args are sorted
# so that functions with smaller op-counts are processed first.
# Ties are broken with the default_sort_key.
# XXX Although the method is deterministic no additional work
# has been done to guarantee that the simplest solution is
# returned and that it would be affected be using different
# variables. Though it is possible that this is the case
# one should know that it has not been done intentionally, so
# further improvements may be possible.
# TODO: This probably doesn't need to be completely recomputed at
# each pass.
exps = update_sets(exps, self.newf.atoms(exp),
lambda i: i.exp.is_rational_function(*self.T) and
i.exp.has(*self.T))
pows = update_sets(pows, self.newf.atoms(Pow),
lambda i: i.exp.is_rational_function(*self.T) and
i.exp.has(*self.T))
numpows = update_sets(numpows, set(pows),
lambda i: not i.base.has(*self.T))
sympows = update_sets(sympows, set(pows) - set(numpows),
lambda i: i.base.is_rational_function(*self.T) and
not i.exp.is_Integer)
# The easiest way to deal with non-base E powers is to convert them
# into base E, integrate, and then convert back.
for i in ordered(pows):
old = i
new = exp(i.exp*log(i.base))
# If exp is ever changed to automatically reduce exp(x*log(2))
# to 2**x, then this will break. The solution is to not change
# exp to do that :)
if i in sympows:
if i.exp.is_Rational:
raise NotImplementedError("Algebraic extensions are "
"not supported (%s)." % str(i))
# We can add a**b only if log(a) in the extension, because
# a**b == exp(b*log(a)).
basea, based = frac_in(i.base, self.t)
A = is_deriv_k(basea, based, self)
if A is None:
# Nonelementary monomial (so far)
# TODO: Would there ever be any benefit from just
# adding log(base) as a new monomial?
# ANSWER: Yes, otherwise we can't integrate x**x (or
# rather prove that it has no elementary integral)
# without first manually rewriting it as exp(x*log(x))
self.newf = self.newf.xreplace({old: new})
self.backsubs += [(new, old)]
log_new_extension = self._log_part([log(i.base)])
exps = update_sets(exps, self.newf.atoms(exp), lambda i:
i.exp.is_rational_function(*self.T) and i.exp.has(*self.T))
continue
ans, u, const = A
newterm = exp(i.exp*(log(const) + u))
# Under the current implementation, exp kills terms
# only if they are of the form a*log(x), where a is a
# Number. This case should have already been killed by the
# above tests. Again, if this changes to kill more than
# that, this will break, which maybe is a sign that you
# shouldn't be changing that. Actually, if anything, this
# auto-simplification should be removed. See
# https://groups.google.com/group/sympy/browse_thread/thread/a61d48235f16867f
self.newf = self.newf.xreplace({i: newterm})
elif i not in numpows:
continue
else:
# i in numpows
newterm = new
# TODO: Just put it in self.Tfuncs
self.backsubs.append((new, old))
self.newf = self.newf.xreplace({old: newterm})
exps.append(newterm)
return exps, pows, numpows, sympows, log_new_extension
def _rewrite_logs(self, logs, symlogs):
"""
Rewrite logs for better processing.
"""
atoms = self.newf.atoms(log)
logs = update_sets(logs, atoms,
lambda i: i.args[0].is_rational_function(*self.T) and
i.args[0].has(*self.T))
symlogs = update_sets(symlogs, atoms,
lambda i: i.has(*self.T) and i.args[0].is_Pow and
i.args[0].base.is_rational_function(*self.T) and
not i.args[0].exp.is_Integer)
# We can handle things like log(x**y) by converting it to y*log(x)
# This will fix not only symbolic exponents of the argument, but any
# non-Integer exponent, like log(sqrt(x)). The exponent can also
# depend on x, like log(x**x).
for i in ordered(symlogs):
# Unlike in the exponential case above, we do not ever
# potentially add new monomials (above we had to add log(a)).
# Therefore, there is no need to run any is_deriv functions
# here. Just convert log(a**b) to b*log(a) and let
# log_new_extension() handle it from there.
lbase = log(i.args[0].base)
logs.append(lbase)
new = i.args[0].exp*lbase
self.newf = self.newf.xreplace({i: new})
self.backsubs.append((new, i))
# remove any duplicates
logs = sorted(set(logs), key=default_sort_key)
return logs, symlogs
def _auto_attrs(self):
"""
Set attributes that are generated automatically.
"""
if not self.T:
# i.e., when using the extension flag and T isn't given
self.T = [i.gen for i in self.D]
if not self.x:
self.x = self.T[0]
self.cases = [get_case(d, t) for d, t in zip(self.D, self.T)]
self.level = -1
self.t = self.T[self.level]
self.d = self.D[self.level]
self.case = self.cases[self.level]
def _exp_part(self, exps):
"""
Try to build an exponential extension.
Returns
=======
Returns True if there was a new extension, False if there was no new
extension but it was able to rewrite the given exponentials in terms
of the existing extension, and None if the entire extension building
process should be restarted. If the process fails because there is no
way around an algebraic extension (e.g., exp(log(x)/2)), it will raise
NotImplementedError.
"""
from .prde import is_log_deriv_k_t_radical
new_extension = False
restart = False
expargs = [i.exp for i in exps]
ip = integer_powers(expargs)
for arg, others in ip:
# Minimize potential problems with algebraic substitution
others.sort(key=lambda i: i[1])
arga, argd = frac_in(arg, self.t)
A = is_log_deriv_k_t_radical(arga, argd, self)
if A is not None:
ans, u, n, const = A
# if n is 1 or -1, it's algebraic, but we can handle it
if n == -1:
# This probably will never happen, because
# Rational.as_numer_denom() returns the negative term in
# the numerator. But in case that changes, reduce it to
# n == 1.
n = 1
u **= -1
const *= -1
ans = [(i, -j) for i, j in ans]
if n == 1:
# Example: exp(x + x**2) over QQ(x, exp(x), exp(x**2))
self.newf = self.newf.xreplace({exp(arg): exp(const)*Mul(*[
u**power for u, power in ans])})
self.newf = self.newf.xreplace({exp(p*exparg):
exp(const*p) * Mul(*[u**power for u, power in ans])
for exparg, p in others})
# TODO: Add something to backsubs to put exp(const*p)
# back together.
continue
else:
# Bad news: we have an algebraic radical. But maybe we
# could still avoid it by choosing a different extension.
# For example, integer_powers() won't handle exp(x/2 + 1)
# over QQ(x, exp(x)), but if we pull out the exp(1), it
# will. Or maybe we have exp(x + x**2/2), over
# QQ(x, exp(x), exp(x**2)), which is exp(x)*sqrt(exp(x**2)),
# but if we use QQ(x, exp(x), exp(x**2/2)), then they will
# all work.
#
# So here is what we do: If there is a non-zero const, pull
# it out and retry. Also, if len(ans) > 1, then rewrite
# exp(arg) as the product of exponentials from ans, and
# retry that. If const == 0 and len(ans) == 1, then we
# assume that it would have been handled by either
# integer_powers() or n == 1 above if it could be handled,
# so we give up at that point. For example, you can never
# handle exp(log(x)/2) because it equals sqrt(x).
if const or len(ans) > 1:
rad = Mul(*[term**(power/n) for term, power in ans])
self.newf = self.newf.xreplace({exp(p*exparg):
exp(const*p)*rad for exparg, p in others})
self.newf = self.newf.xreplace(dict(list(zip(reversed(self.T),
reversed([f(self.x) for f in self.Tfuncs])))))
restart = True
break
else:
# TODO: give algebraic dependence in error string
raise NotImplementedError("Cannot integrate over "
"algebraic extensions.")
else:
arga, argd = frac_in(arg, self.t)
darga = (argd*derivation(Poly(arga, self.t), self) -
arga*derivation(Poly(argd, self.t), self))
dargd = argd**2
darga, dargd = darga.cancel(dargd, include=True)
darg = darga.as_expr()/dargd.as_expr()
self.t = next(self.ts)
self.T.append(self.t)
self.extargs.append(arg)
self.exts.append('exp')
self.D.append(darg.as_poly(self.t, expand=False)*Poly(self.t,
self.t, expand=False))
if self.dummy:
i = Dummy("i")
else:
i = Symbol('i')
self.Tfuncs += [Lambda(i, exp(arg.subs(self.x, i)))]
self.newf = self.newf.xreplace(
{exp(exparg): self.t**p for exparg, p in others})
new_extension = True
if restart:
return None
return new_extension
def _log_part(self, logs):
"""
Try to build a logarithmic extension.
Returns
=======
Returns True if there was a new extension and False if there was no new
extension but it was able to rewrite the given logarithms in terms
of the existing extension. Unlike with exponential extensions, there
is no way that a logarithm is not transcendental over and cannot be
rewritten in terms of an already existing extension in a non-algebraic
way, so this function does not ever return None or raise
NotImplementedError.
"""
from .prde import is_deriv_k
new_extension = False
logargs = [i.args[0] for i in logs]
for arg in ordered(logargs):
# The log case is easier, because whenever a logarithm is algebraic
# over the base field, it is of the form a1*t1 + ... an*tn + c,
# which is a polynomial, so we can just replace it with that.
# In other words, we don't have to worry about radicals.
arga, argd = frac_in(arg, self.t)
A = is_deriv_k(arga, argd, self)
if A is not None:
ans, u, const = A
newterm = log(const) + u
self.newf = self.newf.xreplace({log(arg): newterm})
continue
else:
arga, argd = frac_in(arg, self.t)
darga = (argd*derivation(Poly(arga, self.t), self) -
arga*derivation(Poly(argd, self.t), self))
dargd = argd**2
darg = darga.as_expr()/dargd.as_expr()
self.t = next(self.ts)
self.T.append(self.t)
self.extargs.append(arg)
self.exts.append('log')
self.D.append(cancel(darg.as_expr()/arg).as_poly(self.t,
expand=False))
if self.dummy:
i = Dummy("i")
else:
i = Symbol('i')
self.Tfuncs += [Lambda(i, log(arg.subs(self.x, i)))]
self.newf = self.newf.xreplace({log(arg): self.t})
new_extension = True
return new_extension
@property
def _important_attrs(self):
"""
Returns some of the more important attributes of self.
Explanation
===========
Used for testing and debugging purposes.
The attributes are (fa, fd, D, T, Tfuncs, backsubs,
exts, extargs).
"""
return (self.fa, self.fd, self.D, self.T, self.Tfuncs,
self.backsubs, self.exts, self.extargs)
# NOTE: this printing doesn't follow the Python's standard
# eval(repr(DE)) == DE, where DE is the DifferentialExtension object,
# also this printing is supposed to contain all the important
# attributes of a DifferentialExtension object
def __repr__(self):
# no need to have GeneratorType object printed in it
r = [(attr, getattr(self, attr)) for attr in self.__slots__
if not isinstance(getattr(self, attr), GeneratorType)]
return self.__class__.__name__ + '(dict(%r))' % (r)
# fancy printing of DifferentialExtension object
def __str__(self):
return (self.__class__.__name__ + '({fa=%s, fd=%s, D=%s})' %
(self.fa, self.fd, self.D))
# should only be used for debugging purposes, internally
# f1 = f2 = log(x) at different places in code execution
# may return D1 != D2 as True, since 'level' or other attribute
# may differ
def __eq__(self, other):
for attr in self.__class__.__slots__:
d1, d2 = getattr(self, attr), getattr(other, attr)
if not (isinstance(d1, GeneratorType) or d1 == d2):
return False
return True
def reset(self):
"""
Reset self to an initial state. Used by __init__.
"""
self.t = self.x
self.T = [self.x]
self.D = [Poly(1, self.x)]
self.level = -1
self.exts = [None]
self.extargs = [None]
if self.dummy:
self.ts = numbered_symbols('t', cls=Dummy)
else:
# For testing
self.ts = numbered_symbols('t')
# For various things that we change to make things work that we need to
# change back when we are done.
self.backsubs = []
self.Tfuncs = []
self.newf = self.f
def indices(self, extension):
"""
Parameters
==========
extension : str
Represents a valid extension type.
Returns
=======
list: A list of indices of 'exts' where extension of
type 'extension' is present.
Examples
========
>>> from sympy.integrals.risch import DifferentialExtension
>>> from sympy import log, exp
>>> from sympy.abc import x
>>> DE = DifferentialExtension(log(x) + exp(x), x, handle_first='exp')
>>> DE.indices('log')
[2]
>>> DE.indices('exp')
[1]
"""
return [i for i, ext in enumerate(self.exts) if ext == extension]
def increment_level(self):
"""
Increment the level of self.
Explanation
===========
This makes the working differential extension larger. self.level is
given relative to the end of the list (-1, -2, etc.), so we do not need
do worry about it when building the extension.
"""
if self.level >= -1:
raise ValueError("The level of the differential extension cannot "
"be incremented any further.")
self.level += 1
self.t = self.T[self.level]
self.d = self.D[self.level]
self.case = self.cases[self.level]
return None
def decrement_level(self):
"""
Decrease the level of self.
Explanation
===========
This makes the working differential extension smaller. self.level is
given relative to the end of the list (-1, -2, etc.), so we do not need
do worry about it when building the extension.
"""
if self.level <= -len(self.T):
raise ValueError("The level of the differential extension cannot "
"be decremented any further.")
self.level -= 1
self.t = self.T[self.level]
self.d = self.D[self.level]
self.case = self.cases[self.level]
return None
def update_sets(seq, atoms, func):
s = set(seq)
s = atoms.intersection(s)
new = atoms - s
s.update(list(filter(func, new)))
return list(s)
class DecrementLevel:
"""
A context manager for decrementing the level of a DifferentialExtension.
"""
__slots__ = ('DE',)
def __init__(self, DE):
self.DE = DE
return
def __enter__(self):
self.DE.decrement_level()
def __exit__(self, exc_type, exc_value, traceback):
self.DE.increment_level()
class NonElementaryIntegralException(Exception):
"""
Exception used by subroutines within the Risch algorithm to indicate to one
another that the function being integrated does not have an elementary
integral in the given differential field.
"""
# TODO: Rewrite algorithms below to use this (?)
# TODO: Pass through information about why the integral was nonelementary,
# and store that in the resulting NonElementaryIntegral somehow.
pass
def gcdex_diophantine(a, b, c):
"""
Extended Euclidean Algorithm, Diophantine version.
Explanation
===========
Given ``a``, ``b`` in K[x] and ``c`` in (a, b), the ideal generated by ``a`` and
``b``, return (s, t) such that s*a + t*b == c and either s == 0 or s.degree()
< b.degree().
"""
# Extended Euclidean Algorithm (Diophantine Version) pg. 13
# TODO: This should go in densetools.py.
# XXX: Bettter name?
s, g = a.half_gcdex(b)
s *= c.exquo(g) # Inexact division means c is not in (a, b)
if s and s.degree() >= b.degree():
_, s = s.div(b)
t = (c - s*a).exquo(b)
return (s, t)
def frac_in(f, t, *, cancel=False, **kwargs):
"""
Returns the tuple (fa, fd), where fa and fd are Polys in t.
Explanation
===========
This is a common idiom in the Risch Algorithm functions, so we abstract
it out here. ``f`` should be a basic expression, a Poly, or a tuple (fa, fd),
where fa and fd are either basic expressions or Polys, and f == fa/fd.
**kwargs are applied to Poly.
"""
if isinstance(f, tuple):
fa, fd = f
f = fa.as_expr()/fd.as_expr()
fa, fd = f.as_expr().as_numer_denom()
fa, fd = fa.as_poly(t, **kwargs), fd.as_poly(t, **kwargs)
if cancel:
fa, fd = fa.cancel(fd, include=True)
if fa is None or fd is None:
raise ValueError("Could not turn %s into a fraction in %s." % (f, t))
return (fa, fd)
def as_poly_1t(p, t, z):
"""
(Hackish) way to convert an element ``p`` of K[t, 1/t] to K[t, z].
In other words, ``z == 1/t`` will be a dummy variable that Poly can handle
better.
See issue 5131.
Examples
========
>>> from sympy import random_poly
>>> from sympy.integrals.risch import as_poly_1t
>>> from sympy.abc import x, z
>>> p1 = random_poly(x, 10, -10, 10)
>>> p2 = random_poly(x, 10, -10, 10)
>>> p = p1 + p2.subs(x, 1/x)
>>> as_poly_1t(p, x, z).as_expr().subs(z, 1/x) == p
True
"""
# TODO: Use this on the final result. That way, we can avoid answers like
# (...)*exp(-x).
pa, pd = frac_in(p, t, cancel=True)
if not pd.is_monomial:
# XXX: Is there a better Poly exception that we could raise here?
# Either way, if you see this (from the Risch Algorithm) it indicates
# a bug.
raise PolynomialError("%s is not an element of K[%s, 1/%s]." % (p, t, t))
t_part, remainder = pa.div(pd)
ans = t_part.as_poly(t, z, expand=False)
if remainder:
one = remainder.one
tp = t*one
r = pd.degree() - remainder.degree()
z_part = remainder.transform(one, tp) * tp**r
z_part = z_part.replace(t, z).to_field().quo_ground(pd.LC())
ans += z_part.as_poly(t, z, expand=False)
return ans
def derivation(p, DE, coefficientD=False, basic=False):
"""
Computes Dp.
Explanation
===========
Given the derivation D with D = d/dx and p is a polynomial in t over
K(x), return Dp.
If coefficientD is True, it computes the derivation kD
(kappaD), which is defined as kD(sum(ai*Xi**i, (i, 0, n))) ==
sum(Dai*Xi**i, (i, 1, n)) (Definition 3.2.2, page 80). X in this case is
T[-1], so coefficientD computes the derivative just with respect to T[:-1],
with T[-1] treated as a constant.
If ``basic=True``, the returns a Basic expression. Elements of D can still be
instances of Poly.
"""
if basic:
r = 0
else:
r = Poly(0, DE.t)
t = DE.t
if coefficientD:
if DE.level <= -len(DE.T):
# 'base' case, the answer is 0.
return r
DE.decrement_level()
D = DE.D[:len(DE.D) + DE.level + 1]
T = DE.T[:len(DE.T) + DE.level + 1]
for d, v in zip(D, T):
pv = p.as_poly(v)
if pv is None or basic:
pv = p.as_expr()
if basic:
r += d.as_expr()*pv.diff(v)
else:
r += (d.as_expr()*pv.diff(v).as_expr()).as_poly(t)
if basic:
r = cancel(r)
if coefficientD:
DE.increment_level()
return r
def get_case(d, t):
"""
Returns the type of the derivation d.
Returns one of {'exp', 'tan', 'base', 'primitive', 'other_linear',
'other_nonlinear'}.
"""
if not d.expr.has(t):
if d.is_one:
return 'base'
return 'primitive'
if d.rem(Poly(t, t)).is_zero:
return 'exp'
if d.rem(Poly(1 + t**2, t)).is_zero:
return 'tan'
if d.degree(t) > 1:
return 'other_nonlinear'
return 'other_linear'
def splitfactor(p, DE, coefficientD=False, z=None):
"""
Splitting factorization.
Explanation
===========
Given a derivation D on k[t] and ``p`` in k[t], return (p_n, p_s) in
k[t] x k[t] such that p = p_n*p_s, p_s is special, and each square
factor of p_n is normal.
Page. 100
"""
kinv = [1/x for x in DE.T[:DE.level]]
if z:
kinv.append(z)
One = Poly(1, DE.t, domain=p.get_domain())
Dp = derivation(p, DE, coefficientD=coefficientD)
# XXX: Is this right?
if p.is_zero:
return (p, One)
if not p.expr.has(DE.t):
s = p.as_poly(*kinv).gcd(Dp.as_poly(*kinv)).as_poly(DE.t)
n = p.exquo(s)
return (n, s)
if not Dp.is_zero:
h = p.gcd(Dp).to_field()
g = p.gcd(p.diff(DE.t)).to_field()
s = h.exquo(g)
if s.degree(DE.t) == 0:
return (p, One)
q_split = splitfactor(p.exquo(s), DE, coefficientD=coefficientD)
return (q_split[0], q_split[1]*s)
else:
return (p, One)
def splitfactor_sqf(p, DE, coefficientD=False, z=None, basic=False):
"""
Splitting Square-free Factorization.
Explanation
===========
Given a derivation D on k[t] and ``p`` in k[t], returns (N1, ..., Nm)
and (S1, ..., Sm) in k[t]^m such that p =
(N1*N2**2*...*Nm**m)*(S1*S2**2*...*Sm**m) is a splitting
factorization of ``p`` and the Ni and Si are square-free and coprime.
"""
# TODO: This algorithm appears to be faster in every case
# TODO: Verify this and splitfactor() for multiple extensions
kkinv = [1/x for x in DE.T[:DE.level]] + DE.T[:DE.level]
if z:
kkinv = [z]
S = []
N = []
p_sqf = p.sqf_list_include()
if p.is_zero:
return (((p, 1),), ())
for pi, i in p_sqf:
Si = pi.as_poly(*kkinv).gcd(derivation(pi, DE,
coefficientD=coefficientD,basic=basic).as_poly(*kkinv)).as_poly(DE.t)
pi = Poly(pi, DE.t)
Si = Poly(Si, DE.t)
Ni = pi.exquo(Si)
if not Si.is_one:
S.append((Si, i))
if not Ni.is_one:
N.append((Ni, i))
return (tuple(N), tuple(S))
def canonical_representation(a, d, DE):
"""
Canonical Representation.
Explanation
===========
Given a derivation D on k[t] and f = a/d in k(t), return (f_p, f_s,
f_n) in k[t] x k(t) x k(t) such that f = f_p + f_s + f_n is the
canonical representation of f (f_p is a polynomial, f_s is reduced
(has a special denominator), and f_n is simple (has a normal
denominator).
"""
# Make d monic
l = Poly(1/d.LC(), DE.t)
a, d = a.mul(l), d.mul(l)
q, r = a.div(d)
dn, ds = splitfactor(d, DE)
b, c = gcdex_diophantine(dn.as_poly(DE.t), ds.as_poly(DE.t), r.as_poly(DE.t))
b, c = b.as_poly(DE.t), c.as_poly(DE.t)
return (q, (b, ds), (c, dn))
def hermite_reduce(a, d, DE):
"""
Hermite Reduction - Mack's Linear Version.
Given a derivation D on k(t) and f = a/d in k(t), returns g, h, r in
k(t) such that f = Dg + h + r, h is simple, and r is reduced.
"""
# Make d monic
l = Poly(1/d.LC(), DE.t)
a, d = a.mul(l), d.mul(l)
fp, fs, fn = canonical_representation(a, d, DE)
a, d = fn
l = Poly(1/d.LC(), DE.t)
a, d = a.mul(l), d.mul(l)
ga = Poly(0, DE.t)
gd = Poly(1, DE.t)
dd = derivation(d, DE)
dm = gcd(d.to_field(), dd.to_field()).as_poly(DE.t)
ds, _ = d.div(dm)
while dm.degree(DE.t) > 0:
ddm = derivation(dm, DE)
dm2 = gcd(dm.to_field(), ddm.to_field())
dms, _ = dm.div(dm2)
ds_ddm = ds.mul(ddm)
ds_ddm_dm, _ = ds_ddm.div(dm)
b, c = gcdex_diophantine(-ds_ddm_dm.as_poly(DE.t),
dms.as_poly(DE.t), a.as_poly(DE.t))
b, c = b.as_poly(DE.t), c.as_poly(DE.t)
db = derivation(b, DE).as_poly(DE.t)
ds_dms, _ = ds.div(dms)
a = c.as_poly(DE.t) - db.mul(ds_dms).as_poly(DE.t)
ga = ga*dm + b*gd
gd = gd*dm
ga, gd = ga.cancel(gd, include=True)
dm = dm2
q, r = a.div(ds)
ga, gd = ga.cancel(gd, include=True)
r, d = r.cancel(ds, include=True)
rra = q*fs[1] + fp*fs[1] + fs[0]
rrd = fs[1]
rra, rrd = rra.cancel(rrd, include=True)
return ((ga, gd), (r, d), (rra, rrd))
def polynomial_reduce(p, DE):
"""
Polynomial Reduction.
Explanation
===========
Given a derivation D on k(t) and p in k[t] where t is a nonlinear
monomial over k, return q, r in k[t] such that p = Dq + r, and
deg(r) < deg_t(Dt).
"""
q = Poly(0, DE.t)
while p.degree(DE.t) >= DE.d.degree(DE.t):
m = p.degree(DE.t) - DE.d.degree(DE.t) + 1
q0 = Poly(DE.t**m, DE.t).mul(Poly(p.as_poly(DE.t).LC()/
(m*DE.d.LC()), DE.t))
q += q0
p = p - derivation(q0, DE)
return (q, p)
def laurent_series(a, d, F, n, DE):
"""
Contribution of ``F`` to the full partial fraction decomposition of A/D.
Explanation
===========
Given a field K of characteristic 0 and ``A``,``D``,``F`` in K[x] with D monic,
nonzero, coprime with A, and ``F`` the factor of multiplicity n in the square-
free factorization of D, return the principal parts of the Laurent series of
A/D at all the zeros of ``F``.
"""
if F.degree()==0:
return 0
Z = _symbols('z', n)
z = Symbol('z')
Z.insert(0, z)
delta_a = Poly(0, DE.t)
delta_d = Poly(1, DE.t)
E = d.quo(F**n)
ha, hd = (a, E*Poly(z**n, DE.t))
dF = derivation(F,DE)
B, _ = gcdex_diophantine(E, F, Poly(1,DE.t))
C, _ = gcdex_diophantine(dF, F, Poly(1,DE.t))
# initialization
F_store = F
V, DE_D_list, H_list= [], [], []
for j in range(0, n):
# jth derivative of z would be substituted with dfnth/(j+1) where dfnth =(d^n)f/(dx)^n
F_store = derivation(F_store, DE)
v = (F_store.as_expr())/(j + 1)
V.append(v)
DE_D_list.append(Poly(Z[j + 1],Z[j]))
DE_new = DifferentialExtension(extension = {'D': DE_D_list}) #a differential indeterminate
for j in range(0, n):
zEha = Poly(z**(n + j), DE.t)*E**(j + 1)*ha
zEhd = hd
Pa, Pd = cancel((zEha, zEhd))[1], cancel((zEha, zEhd))[2]
Q = Pa.quo(Pd)
for i in range(0, j + 1):
Q = Q.subs(Z[i], V[i])
Dha = (hd*derivation(ha, DE, basic=True).as_poly(DE.t)
+ ha*derivation(hd, DE, basic=True).as_poly(DE.t)
+ hd*derivation(ha, DE_new, basic=True).as_poly(DE.t)
+ ha*derivation(hd, DE_new, basic=True).as_poly(DE.t))
Dhd = Poly(j + 1, DE.t)*hd**2
ha, hd = Dha, Dhd
Ff, _ = F.div(gcd(F, Q))
F_stara, F_stard = frac_in(Ff, DE.t)
if F_stara.degree(DE.t) - F_stard.degree(DE.t) > 0:
QBC = Poly(Q, DE.t)*B**(1 + j)*C**(n + j)
H = QBC
H_list.append(H)
H = (QBC*F_stard).rem(F_stara)
alphas = real_roots(F_stara)
for alpha in list(alphas):
delta_a = delta_a*Poly((DE.t - alpha)**(n - j), DE.t) + Poly(H.eval(alpha), DE.t)
delta_d = delta_d*Poly((DE.t - alpha)**(n - j), DE.t)
return (delta_a, delta_d, H_list)
def recognize_derivative(a, d, DE, z=None):
"""
Compute the squarefree factorization of the denominator of f
and for each Di the polynomial H in K[x] (see Theorem 2.7.1), using the
LaurentSeries algorithm. Write Di = GiEi where Gj = gcd(Hn, Di) and
gcd(Ei,Hn) = 1. Since the residues of f at the roots of Gj are all 0, and
the residue of f at a root alpha of Ei is Hi(a) != 0, f is the derivative of a
rational function if and only if Ei = 1 for each i, which is equivalent to
Di | H[-1] for each i.
"""
flag =True
a, d = a.cancel(d, include=True)
_, r = a.div(d)
Np, Sp = splitfactor_sqf(d, DE, coefficientD=True, z=z)
j = 1
for s, _ in Sp:
delta_a, delta_d, H = laurent_series(r, d, s, j, DE)
g = gcd(d, H[-1]).as_poly()
if g is not d:
flag = False
break
j = j + 1
return flag
def recognize_log_derivative(a, d, DE, z=None):
"""
There exists a v in K(x)* such that f = dv/v
where f a rational function if and only if f can be written as f = A/D
where D is squarefree,deg(A) < deg(D), gcd(A, D) = 1,
and all the roots of the Rothstein-Trager resultant are integers. In that case,
any of the Rothstein-Trager, Lazard-Rioboo-Trager or Czichowski algorithm
produces u in K(x) such that du/dx = uf.
"""
z = z or Dummy('z')
a, d = a.cancel(d, include=True)
_, a = a.div(d)
pz = Poly(z, DE.t)
Dd = derivation(d, DE)
q = a - pz*Dd
r, _ = d.resultant(q, includePRS=True)
r = Poly(r, z)
Np, Sp = splitfactor_sqf(r, DE, coefficientD=True, z=z)
for s, _ in Sp:
# TODO also consider the complex roots which should
# turn the flag false
a = real_roots(s.as_poly(z))
if not all(j.is_Integer for j in a):
return False
return True
def residue_reduce(a, d, DE, z=None, invert=True):
"""
Lazard-Rioboo-Rothstein-Trager resultant reduction.
Explanation
===========
Given a derivation ``D`` on k(t) and f in k(t) simple, return g
elementary over k(t) and a Boolean b in {True, False} such that f -
Dg in k[t] if b == True or f + h and f + h - Dg do not have an
elementary integral over k(t) for any h in k<t> (reduced) if b ==
False.
Returns (G, b), where G is a tuple of tuples of the form (s_i, S_i),
such that g = Add(*[RootSum(s_i, lambda z: z*log(S_i(z, t))) for
S_i, s_i in G]). f - Dg is the remaining integral, which is elementary
only if b == True, and hence the integral of f is elementary only if
b == True.
f - Dg is not calculated in this function because that would require
explicitly calculating the RootSum. Use residue_reduce_derivation().
"""
# TODO: Use log_to_atan() from rationaltools.py
# If r = residue_reduce(...), then the logarithmic part is given by:
# sum([RootSum(a[0].as_poly(z), lambda i: i*log(a[1].as_expr()).subs(z,
# i)).subs(t, log(x)) for a in r[0]])
z = z or Dummy('z')
a, d = a.cancel(d, include=True)
a, d = a.to_field().mul_ground(1/d.LC()), d.to_field().mul_ground(1/d.LC())
kkinv = [1/x for x in DE.T[:DE.level]] + DE.T[:DE.level]
if a.is_zero:
return ([], True)
_, a = a.div(d)
pz = Poly(z, DE.t)
Dd = derivation(d, DE)
q = a - pz*Dd
if Dd.degree(DE.t) <= d.degree(DE.t):
r, R = d.resultant(q, includePRS=True)
else:
r, R = q.resultant(d, includePRS=True)
R_map, H = {}, []
for i in R:
R_map[i.degree()] = i
r = Poly(r, z)
Np, Sp = splitfactor_sqf(r, DE, coefficientD=True, z=z)
for s, i in Sp:
if i == d.degree(DE.t):
s = Poly(s, z).monic()
H.append((s, d))
else:
h = R_map.get(i)
if h is None:
continue
h_lc = Poly(h.as_poly(DE.t).LC(), DE.t, field=True)
h_lc_sqf = h_lc.sqf_list_include(all=True)
for a, j in h_lc_sqf:
h = Poly(h, DE.t, field=True).exquo(Poly(gcd(a, s**j, *kkinv),
DE.t))
s = Poly(s, z).monic()
if invert:
h_lc = Poly(h.as_poly(DE.t).LC(), DE.t, field=True, expand=False)
inv, coeffs = h_lc.as_poly(z, field=True).invert(s), [S.One]
for coeff in h.coeffs()[1:]:
L = reduced(inv*coeff.as_poly(inv.gens), [s])[1]
coeffs.append(L.as_expr())
h = Poly(dict(list(zip(h.monoms(), coeffs))), DE.t)
H.append((s, h))
b = not any(cancel(i.as_expr()).has(DE.t, z) for i, _ in Np)
return (H, b)
def residue_reduce_to_basic(H, DE, z):
"""
Converts the tuple returned by residue_reduce() into a Basic expression.
"""
# TODO: check what Lambda does with RootOf
i = Dummy('i')
s = list(zip(reversed(DE.T), reversed([f(DE.x) for f in DE.Tfuncs])))
return sum(RootSum(a[0].as_poly(z), Lambda(i, i*log(a[1].as_expr()).subs(
{z: i}).subs(s))) for a in H)
def residue_reduce_derivation(H, DE, z):
"""
Computes the derivation of an expression returned by residue_reduce().
In general, this is a rational function in t, so this returns an
as_expr() result.
"""
# TODO: verify that this is correct for multiple extensions
i = Dummy('i')
return S(sum(RootSum(a[0].as_poly(z), Lambda(i, i*derivation(a[1],
DE).as_expr().subs(z, i)/a[1].as_expr().subs(z, i))) for a in H))
def integrate_primitive_polynomial(p, DE):
"""
Integration of primitive polynomials.
Explanation
===========
Given a primitive monomial t over k, and ``p`` in k[t], return q in k[t],
r in k, and a bool b in {True, False} such that r = p - Dq is in k if b is
True, or r = p - Dq does not have an elementary integral over k(t) if b is
False.
"""
Zero = Poly(0, DE.t)
q = Poly(0, DE.t)
if not p.expr.has(DE.t):
return (Zero, p, True)
from .prde import limited_integrate
while True:
if not p.expr.has(DE.t):
return (q, p, True)
Dta, Dtb = frac_in(DE.d, DE.T[DE.level - 1])
with DecrementLevel(DE): # We had better be integrating the lowest extension (x)
# with ratint().
a = p.LC()
aa, ad = frac_in(a, DE.t)
try:
rv = limited_integrate(aa, ad, [(Dta, Dtb)], DE)
if rv is None:
raise NonElementaryIntegralException
(ba, bd), c = rv
except NonElementaryIntegralException:
return (q, p, False)
m = p.degree(DE.t)
q0 = c[0].as_poly(DE.t)*Poly(DE.t**(m + 1)/(m + 1), DE.t) + \
(ba.as_expr()/bd.as_expr()).as_poly(DE.t)*Poly(DE.t**m, DE.t)
p = p - derivation(q0, DE)
q = q + q0
def integrate_primitive(a, d, DE, z=None):
"""
Integration of primitive functions.
Explanation
===========
Given a primitive monomial t over k and f in k(t), return g elementary over
k(t), i in k(t), and b in {True, False} such that i = f - Dg is in k if b
is True or i = f - Dg does not have an elementary integral over k(t) if b
is False.
This function returns a Basic expression for the first argument. If b is
True, the second argument is Basic expression in k to recursively integrate.
If b is False, the second argument is an unevaluated Integral, which has
been proven to be nonelementary.
"""
# XXX: a and d must be canceled, or this might return incorrect results
z = z or Dummy("z")
s = list(zip(reversed(DE.T), reversed([f(DE.x) for f in DE.Tfuncs])))
g1, h, r = hermite_reduce(a, d, DE)
g2, b = residue_reduce(h[0], h[1], DE, z=z)
if not b:
i = cancel(a.as_expr()/d.as_expr() - (g1[1]*derivation(g1[0], DE) -
g1[0]*derivation(g1[1], DE)).as_expr()/(g1[1]**2).as_expr() -
residue_reduce_derivation(g2, DE, z))
i = NonElementaryIntegral(cancel(i).subs(s), DE.x)
return ((g1[0].as_expr()/g1[1].as_expr()).subs(s) +
residue_reduce_to_basic(g2, DE, z), i, b)
# h - Dg2 + r
p = cancel(h[0].as_expr()/h[1].as_expr() - residue_reduce_derivation(g2,
DE, z) + r[0].as_expr()/r[1].as_expr())
p = p.as_poly(DE.t)
q, i, b = integrate_primitive_polynomial(p, DE)
ret = ((g1[0].as_expr()/g1[1].as_expr() + q.as_expr()).subs(s) +
residue_reduce_to_basic(g2, DE, z))
if not b:
# TODO: This does not do the right thing when b is False
i = NonElementaryIntegral(cancel(i.as_expr()).subs(s), DE.x)
else:
i = cancel(i.as_expr())
return (ret, i, b)
def integrate_hyperexponential_polynomial(p, DE, z):
"""
Integration of hyperexponential polynomials.
Explanation
===========
Given a hyperexponential monomial t over k and ``p`` in k[t, 1/t], return q in
k[t, 1/t] and a bool b in {True, False} such that p - Dq in k if b is True,
or p - Dq does not have an elementary integral over k(t) if b is False.
"""
t1 = DE.t
dtt = DE.d.exquo(Poly(DE.t, DE.t))
qa = Poly(0, DE.t)
qd = Poly(1, DE.t)
b = True
if p.is_zero:
return(qa, qd, b)
from sympy.integrals.rde import rischDE
with DecrementLevel(DE):
for i in range(-p.degree(z), p.degree(t1) + 1):
if not i:
continue
elif i < 0:
# If you get AttributeError: 'NoneType' object has no attribute 'nth'
# then this should really not have expand=False
# But it shouldn't happen because p is already a Poly in t and z
a = p.as_poly(z, expand=False).nth(-i)
else:
# If you get AttributeError: 'NoneType' object has no attribute 'nth'
# then this should really not have expand=False
a = p.as_poly(t1, expand=False).nth(i)
aa, ad = frac_in(a, DE.t, field=True)
aa, ad = aa.cancel(ad, include=True)
iDt = Poly(i, t1)*dtt
iDta, iDtd = frac_in(iDt, DE.t, field=True)
try:
va, vd = rischDE(iDta, iDtd, Poly(aa, DE.t), Poly(ad, DE.t), DE)
va, vd = frac_in((va, vd), t1, cancel=True)
except NonElementaryIntegralException:
b = False
else:
qa = qa*vd + va*Poly(t1**i)*qd
qd *= vd
return (qa, qd, b)
def integrate_hyperexponential(a, d, DE, z=None, conds='piecewise'):
"""
Integration of hyperexponential functions.
Explanation
===========
Given a hyperexponential monomial t over k and f in k(t), return g
elementary over k(t), i in k(t), and a bool b in {True, False} such that
i = f - Dg is in k if b is True or i = f - Dg does not have an elementary
integral over k(t) if b is False.
This function returns a Basic expression for the first argument. If b is
True, the second argument is Basic expression in k to recursively integrate.
If b is False, the second argument is an unevaluated Integral, which has
been proven to be nonelementary.
"""
# XXX: a and d must be canceled, or this might return incorrect results
z = z or Dummy("z")
s = list(zip(reversed(DE.T), reversed([f(DE.x) for f in DE.Tfuncs])))
g1, h, r = hermite_reduce(a, d, DE)
g2, b = residue_reduce(h[0], h[1], DE, z=z)
if not b:
i = cancel(a.as_expr()/d.as_expr() - (g1[1]*derivation(g1[0], DE) -
g1[0]*derivation(g1[1], DE)).as_expr()/(g1[1]**2).as_expr() -
residue_reduce_derivation(g2, DE, z))
i = NonElementaryIntegral(cancel(i.subs(s)), DE.x)
return ((g1[0].as_expr()/g1[1].as_expr()).subs(s) +
residue_reduce_to_basic(g2, DE, z), i, b)
# p should be a polynomial in t and 1/t, because Sirr == k[t, 1/t]
# h - Dg2 + r
p = cancel(h[0].as_expr()/h[1].as_expr() - residue_reduce_derivation(g2,
DE, z) + r[0].as_expr()/r[1].as_expr())
pp = as_poly_1t(p, DE.t, z)
qa, qd, b = integrate_hyperexponential_polynomial(pp, DE, z)
i = pp.nth(0, 0)
ret = ((g1[0].as_expr()/g1[1].as_expr()).subs(s) \
+ residue_reduce_to_basic(g2, DE, z))
qas = qa.as_expr().subs(s)
qds = qd.as_expr().subs(s)
if conds == 'piecewise' and DE.x not in qds.free_symbols:
# We have to be careful if the exponent is S.Zero!
# XXX: Does qd = 0 always necessarily correspond to the exponential
# equaling 1?
ret += Piecewise(
(qas/qds, Ne(qds, 0)),
(integrate((p - i).subs(DE.t, 1).subs(s), DE.x), True)
)
else:
ret += qas/qds
if not b:
i = p - (qd*derivation(qa, DE) - qa*derivation(qd, DE)).as_expr()/\
(qd**2).as_expr()
i = NonElementaryIntegral(cancel(i).subs(s), DE.x)
return (ret, i, b)
def integrate_hypertangent_polynomial(p, DE):
"""
Integration of hypertangent polynomials.
Explanation
===========
Given a differential field k such that sqrt(-1) is not in k, a
hypertangent monomial t over k, and p in k[t], return q in k[t] and
c in k such that p - Dq - c*D(t**2 + 1)/(t**1 + 1) is in k and p -
Dq does not have an elementary integral over k(t) if Dc != 0.
"""
# XXX: Make sure that sqrt(-1) is not in k.
q, r = polynomial_reduce(p, DE)
a = DE.d.exquo(Poly(DE.t**2 + 1, DE.t))
c = Poly(r.nth(1)/(2*a.as_expr()), DE.t)
return (q, c)
def integrate_nonlinear_no_specials(a, d, DE, z=None):
"""
Integration of nonlinear monomials with no specials.
Explanation
===========
Given a nonlinear monomial t over k such that Sirr ({p in k[t] | p is
special, monic, and irreducible}) is empty, and f in k(t), returns g
elementary over k(t) and a Boolean b in {True, False} such that f - Dg is
in k if b == True, or f - Dg does not have an elementary integral over k(t)
if b == False.
This function is applicable to all nonlinear extensions, but in the case
where it returns b == False, it will only have proven that the integral of
f - Dg is nonelementary if Sirr is empty.
This function returns a Basic expression.
"""
# TODO: Integral from k?
# TODO: split out nonelementary integral
# XXX: a and d must be canceled, or this might not return correct results
z = z or Dummy("z")
s = list(zip(reversed(DE.T), reversed([f(DE.x) for f in DE.Tfuncs])))
g1, h, r = hermite_reduce(a, d, DE)
g2, b = residue_reduce(h[0], h[1], DE, z=z)
if not b:
return ((g1[0].as_expr()/g1[1].as_expr()).subs(s) +
residue_reduce_to_basic(g2, DE, z), b)
# Because f has no specials, this should be a polynomial in t, or else
# there is a bug.
p = cancel(h[0].as_expr()/h[1].as_expr() - residue_reduce_derivation(g2,
DE, z).as_expr() + r[0].as_expr()/r[1].as_expr()).as_poly(DE.t)
q1, q2 = polynomial_reduce(p, DE)
if q2.expr.has(DE.t):
b = False
else:
b = True
ret = (cancel(g1[0].as_expr()/g1[1].as_expr() + q1.as_expr()).subs(s) +
residue_reduce_to_basic(g2, DE, z))
return (ret, b)
class NonElementaryIntegral(Integral):
"""
Represents a nonelementary Integral.
Explanation
===========
If the result of integrate() is an instance of this class, it is
guaranteed to be nonelementary. Note that integrate() by default will try
to find any closed-form solution, even in terms of special functions which
may themselves not be elementary. To make integrate() only give
elementary solutions, or, in the cases where it can prove the integral to
be nonelementary, instances of this class, use integrate(risch=True).
In this case, integrate() may raise NotImplementedError if it cannot make
such a determination.
integrate() uses the deterministic Risch algorithm to integrate elementary
functions or prove that they have no elementary integral. In some cases,
this algorithm can split an integral into an elementary and nonelementary
part, so that the result of integrate will be the sum of an elementary
expression and a NonElementaryIntegral.
Examples
========
>>> from sympy import integrate, exp, log, Integral
>>> from sympy.abc import x
>>> a = integrate(exp(-x**2), x, risch=True)
>>> print(a)
Integral(exp(-x**2), x)
>>> type(a)
<class 'sympy.integrals.risch.NonElementaryIntegral'>
>>> expr = (2*log(x)**2 - log(x) - x**2)/(log(x)**3 - x**2*log(x))
>>> b = integrate(expr, x, risch=True)
>>> print(b)
-log(-x + log(x))/2 + log(x + log(x))/2 + Integral(1/log(x), x)
>>> type(b.atoms(Integral).pop())
<class 'sympy.integrals.risch.NonElementaryIntegral'>
"""
# TODO: This is useful in and of itself, because isinstance(result,
# NonElementaryIntegral) will tell if the integral has been proven to be
# elementary. But should we do more? Perhaps a no-op .doit() if
# elementary=True? Or maybe some information on why the integral is
# nonelementary.
pass
def risch_integrate(f, x, extension=None, handle_first='log',
separate_integral=False, rewrite_complex=None,
conds='piecewise'):
r"""
The Risch Integration Algorithm.
Explanation
===========
Only transcendental functions are supported. Currently, only exponentials
and logarithms are supported, but support for trigonometric functions is
forthcoming.
If this function returns an unevaluated Integral in the result, it means
that it has proven that integral to be nonelementary. Any errors will
result in raising NotImplementedError. The unevaluated Integral will be
an instance of NonElementaryIntegral, a subclass of Integral.
handle_first may be either 'exp' or 'log'. This changes the order in
which the extension is built, and may result in a different (but
equivalent) solution (for an example of this, see issue 5109). It is also
possible that the integral may be computed with one but not the other,
because not all cases have been implemented yet. It defaults to 'log' so
that the outer extension is exponential when possible, because more of the
exponential case has been implemented.
If ``separate_integral`` is ``True``, the result is returned as a tuple (ans, i),
where the integral is ans + i, ans is elementary, and i is either a
NonElementaryIntegral or 0. This useful if you want to try further
integrating the NonElementaryIntegral part using other algorithms to
possibly get a solution in terms of special functions. It is False by
default.
Examples
========
>>> from sympy.integrals.risch import risch_integrate
>>> from sympy import exp, log, pprint
>>> from sympy.abc import x
First, we try integrating exp(-x**2). Except for a constant factor of
2/sqrt(pi), this is the famous error function.
>>> pprint(risch_integrate(exp(-x**2), x))
/
|
| 2
| -x
| e dx
|
/
The unevaluated Integral in the result means that risch_integrate() has
proven that exp(-x**2) does not have an elementary anti-derivative.
In many cases, risch_integrate() can split out the elementary
anti-derivative part from the nonelementary anti-derivative part.
For example,
>>> pprint(risch_integrate((2*log(x)**2 - log(x) - x**2)/(log(x)**3 -
... x**2*log(x)), x))
/
|
log(-x + log(x)) log(x + log(x)) | 1
- ---------------- + --------------- + | ------ dx
2 2 | log(x)
|
/
This means that it has proven that the integral of 1/log(x) is
nonelementary. This function is also known as the logarithmic integral,
and is often denoted as Li(x).
risch_integrate() currently only accepts purely transcendental functions
with exponentials and logarithms, though note that this can include
nested exponentials and logarithms, as well as exponentials with bases
other than E.
>>> pprint(risch_integrate(exp(x)*exp(exp(x)), x))
/ x\
\e /
e
>>> pprint(risch_integrate(exp(exp(x)), x))
/
|
| / x\
| \e /
| e dx
|
/
>>> pprint(risch_integrate(x*x**x*log(x) + x**x + x*x**x, x))
x
x*x
>>> pprint(risch_integrate(x**x, x))
/
|
| x
| x dx
|
/
>>> pprint(risch_integrate(-1/(x*log(x)*log(log(x))**2), x))
1
-----------
log(log(x))
"""
f = S(f)
DE = extension or DifferentialExtension(f, x, handle_first=handle_first,
dummy=True, rewrite_complex=rewrite_complex)
fa, fd = DE.fa, DE.fd
result = S.Zero
for case in reversed(DE.cases):
if not fa.expr.has(DE.t) and not fd.expr.has(DE.t) and not case == 'base':
DE.decrement_level()
fa, fd = frac_in((fa, fd), DE.t)
continue
fa, fd = fa.cancel(fd, include=True)
if case == 'exp':
ans, i, b = integrate_hyperexponential(fa, fd, DE, conds=conds)
elif case == 'primitive':
ans, i, b = integrate_primitive(fa, fd, DE)
elif case == 'base':
# XXX: We can't call ratint() directly here because it doesn't
# handle polynomials correctly.
ans = integrate(fa.as_expr()/fd.as_expr(), DE.x, risch=False)
b = False
i = S.Zero
else:
raise NotImplementedError("Only exponential and logarithmic "
"extensions are currently supported.")
result += ans
if b:
DE.decrement_level()
fa, fd = frac_in(i, DE.t)
else:
result = result.subs(DE.backsubs)
if not i.is_zero:
i = NonElementaryIntegral(i.function.subs(DE.backsubs),i.limits)
if not separate_integral:
result += i
return result
else:
if isinstance(i, NonElementaryIntegral):
return (result, i)
else:
return (result, 0)
PK ]ZZZ���Ļ � ' sympy/integrals/singularityfunctions.pyfrom sympy.functions import SingularityFunction, DiracDelta
from sympy.integrals import integrate
def singularityintegrate(f, x):
"""
This function handles the indefinite integrations of Singularity functions.
The ``integrate`` function calls this function internally whenever an
instance of SingularityFunction is passed as argument.
Explanation
===========
The idea for integration is the following:
- If we are dealing with a SingularityFunction expression,
i.e. ``SingularityFunction(x, a, n)``, we just return
``SingularityFunction(x, a, n + 1)/(n + 1)`` if ``n >= 0`` and
``SingularityFunction(x, a, n + 1)`` if ``n < 0``.
- If the node is a multiplication or power node having a
SingularityFunction term we rewrite the whole expression in terms of
Heaviside and DiracDelta and then integrate the output. Lastly, we
rewrite the output of integration back in terms of SingularityFunction.
- If none of the above case arises, we return None.
Examples
========
>>> from sympy.integrals.singularityfunctions import singularityintegrate
>>> from sympy import SingularityFunction, symbols, Function
>>> x, a, n, y = symbols('x a n y')
>>> f = Function('f')
>>> singularityintegrate(SingularityFunction(x, a, 3), x)
SingularityFunction(x, a, 4)/4
>>> singularityintegrate(5*SingularityFunction(x, 5, -2), x)
5*SingularityFunction(x, 5, -1)
>>> singularityintegrate(6*SingularityFunction(x, 5, -1), x)
6*SingularityFunction(x, 5, 0)
>>> singularityintegrate(x*SingularityFunction(x, 0, -1), x)
0
>>> singularityintegrate(SingularityFunction(x, 1, -1) * f(x), x)
f(1)*SingularityFunction(x, 1, 0)
"""
if not f.has(SingularityFunction):
return None
if isinstance(f, SingularityFunction):
x, a, n = f.args
if n.is_positive or n.is_zero:
return SingularityFunction(x, a, n + 1)/(n + 1)
elif n in (-1, -2, -3, -4):
return SingularityFunction(x, a, n + 1)
if f.is_Mul or f.is_Pow:
expr = f.rewrite(DiracDelta)
expr = integrate(expr, x)
return expr.rewrite(SingularityFunction)
return None
PK ]ZZZ o�v$� $� sympy/integrals/transforms.py""" Integral Transforms """
from functools import reduce, wraps
from itertools import repeat
from sympy.core import S, pi
from sympy.core.add import Add
from sympy.core.function import (
AppliedUndef, count_ops, expand, expand_mul, Function)
from sympy.core.mul import Mul
from sympy.core.intfunc import igcd, ilcm
from sympy.core.sorting import default_sort_key
from sympy.core.symbol import Dummy
from sympy.core.traversal import postorder_traversal
from sympy.functions.combinatorial.factorials import factorial, rf
from sympy.functions.elementary.complexes import re, arg, Abs
from sympy.functions.elementary.exponential import exp, exp_polar
from sympy.functions.elementary.hyperbolic import cosh, coth, sinh, tanh
from sympy.functions.elementary.integers import ceiling
from sympy.functions.elementary.miscellaneous import Max, Min, sqrt
from sympy.functions.elementary.piecewise import piecewise_fold
from sympy.functions.elementary.trigonometric import cos, cot, sin, tan
from sympy.functions.special.bessel import besselj
from sympy.functions.special.delta_functions import Heaviside
from sympy.functions.special.gamma_functions import gamma
from sympy.functions.special.hyper import meijerg
from sympy.integrals import integrate, Integral
from sympy.integrals.meijerint import _dummy
from sympy.logic.boolalg import to_cnf, conjuncts, disjuncts, Or, And
from sympy.polys.polyroots import roots
from sympy.polys.polytools import factor, Poly
from sympy.polys.rootoftools import CRootOf
from sympy.utilities.iterables import iterable
from sympy.utilities.misc import debug
##########################################################################
# Helpers / Utilities
##########################################################################
class IntegralTransformError(NotImplementedError):
"""
Exception raised in relation to problems computing transforms.
Explanation
===========
This class is mostly used internally; if integrals cannot be computed
objects representing unevaluated transforms are usually returned.
The hint ``needeval=True`` can be used to disable returning transform
objects, and instead raise this exception if an integral cannot be
computed.
"""
def __init__(self, transform, function, msg):
super().__init__(
"%s Transform could not be computed: %s." % (transform, msg))
self.function = function
class IntegralTransform(Function):
"""
Base class for integral transforms.
Explanation
===========
This class represents unevaluated transforms.
To implement a concrete transform, derive from this class and implement
the ``_compute_transform(f, x, s, **hints)`` and ``_as_integral(f, x, s)``
functions. If the transform cannot be computed, raise :obj:`IntegralTransformError`.
Also set ``cls._name``. For instance,
>>> from sympy import LaplaceTransform
>>> LaplaceTransform._name
'Laplace'
Implement ``self._collapse_extra`` if your function returns more than just a
number and possibly a convergence condition.
"""
@property
def function(self):
""" The function to be transformed. """
return self.args[0]
@property
def function_variable(self):
""" The dependent variable of the function to be transformed. """
return self.args[1]
@property
def transform_variable(self):
""" The independent transform variable. """
return self.args[2]
@property
def free_symbols(self):
"""
This method returns the symbols that will exist when the transform
is evaluated.
"""
return self.function.free_symbols.union({self.transform_variable}) \
- {self.function_variable}
def _compute_transform(self, f, x, s, **hints):
raise NotImplementedError
def _as_integral(self, f, x, s):
raise NotImplementedError
def _collapse_extra(self, extra):
cond = And(*extra)
if cond == False:
raise IntegralTransformError(self.__class__.name, None, '')
return cond
def _try_directly(self, **hints):
T = None
try_directly = not any(func.has(self.function_variable)
for func in self.function.atoms(AppliedUndef))
if try_directly:
try:
T = self._compute_transform(self.function,
self.function_variable, self.transform_variable, **hints)
except IntegralTransformError:
debug('[IT _try ] Caught IntegralTransformError, returns None')
T = None
fn = self.function
if not fn.is_Add:
fn = expand_mul(fn)
return fn, T
def doit(self, **hints):
"""
Try to evaluate the transform in closed form.
Explanation
===========
This general function handles linearity, but apart from that leaves
pretty much everything to _compute_transform.
Standard hints are the following:
- ``simplify``: whether or not to simplify the result
- ``noconds``: if True, do not return convergence conditions
- ``needeval``: if True, raise IntegralTransformError instead of
returning IntegralTransform objects
The default values of these hints depend on the concrete transform,
usually the default is
``(simplify, noconds, needeval) = (True, False, False)``.
"""
needeval = hints.pop('needeval', False)
simplify = hints.pop('simplify', True)
hints['simplify'] = simplify
fn, T = self._try_directly(**hints)
if T is not None:
return T
if fn.is_Add:
hints['needeval'] = needeval
res = [self.__class__(*([x] + list(self.args[1:]))).doit(**hints)
for x in fn.args]
extra = []
ress = []
for x in res:
if not isinstance(x, tuple):
x = [x]
ress.append(x[0])
if len(x) == 2:
# only a condition
extra.append(x[1])
elif len(x) > 2:
# some region parameters and a condition (Mellin, Laplace)
extra += [x[1:]]
if simplify==True:
res = Add(*ress).simplify()
else:
res = Add(*ress)
if not extra:
return res
try:
extra = self._collapse_extra(extra)
if iterable(extra):
return (res,) + tuple(extra)
else:
return (res, extra)
except IntegralTransformError:
pass
if needeval:
raise IntegralTransformError(
self.__class__._name, self.function, 'needeval')
# TODO handle derivatives etc
# pull out constant coefficients
coeff, rest = fn.as_coeff_mul(self.function_variable)
return coeff*self.__class__(*([Mul(*rest)] + list(self.args[1:])))
@property
def as_integral(self):
return self._as_integral(self.function, self.function_variable,
self.transform_variable)
def _eval_rewrite_as_Integral(self, *args, **kwargs):
return self.as_integral
def _simplify(expr, doit):
if doit:
from sympy.simplify import simplify
from sympy.simplify.powsimp import powdenest
return simplify(powdenest(piecewise_fold(expr), polar=True))
return expr
def _noconds_(default):
"""
This is a decorator generator for dropping convergence conditions.
Explanation
===========
Suppose you define a function ``transform(*args)`` which returns a tuple of
the form ``(result, cond1, cond2, ...)``.
Decorating it ``@_noconds_(default)`` will add a new keyword argument
``noconds`` to it. If ``noconds=True``, the return value will be altered to
be only ``result``, whereas if ``noconds=False`` the return value will not
be altered.
The default value of the ``noconds`` keyword will be ``default`` (i.e. the
argument of this function).
"""
def make_wrapper(func):
@wraps(func)
def wrapper(*args, noconds=default, **kwargs):
res = func(*args, **kwargs)
if noconds:
return res[0]
return res
return wrapper
return make_wrapper
_noconds = _noconds_(False)
##########################################################################
# Mellin Transform
##########################################################################
def _default_integrator(f, x):
return integrate(f, (x, S.Zero, S.Infinity))
@_noconds
def _mellin_transform(f, x, s_, integrator=_default_integrator, simplify=True):
""" Backend function to compute Mellin transforms. """
# We use a fresh dummy, because assumptions on s might drop conditions on
# convergence of the integral.
s = _dummy('s', 'mellin-transform', f)
F = integrator(x**(s - 1) * f, x)
if not F.has(Integral):
return _simplify(F.subs(s, s_), simplify), (S.NegativeInfinity, S.Infinity), S.true
if not F.is_Piecewise: # XXX can this work if integration gives continuous result now?
raise IntegralTransformError('Mellin', f, 'could not compute integral')
F, cond = F.args[0]
if F.has(Integral):
raise IntegralTransformError(
'Mellin', f, 'integral in unexpected form')
def process_conds(cond):
"""
Turn ``cond`` into a strip (a, b), and auxiliary conditions.
"""
from sympy.solvers.inequalities import _solve_inequality
a = S.NegativeInfinity
b = S.Infinity
aux = S.true
conds = conjuncts(to_cnf(cond))
t = Dummy('t', real=True)
for c in conds:
a_ = S.Infinity
b_ = S.NegativeInfinity
aux_ = []
for d in disjuncts(c):
d_ = d.replace(
re, lambda x: x.as_real_imag()[0]).subs(re(s), t)
if not d.is_Relational or \
d.rel_op in ('==', '!=') \
or d_.has(s) or not d_.has(t):
aux_ += [d]
continue
soln = _solve_inequality(d_, t)
if not soln.is_Relational or \
soln.rel_op in ('==', '!='):
aux_ += [d]
continue
if soln.lts == t:
b_ = Max(soln.gts, b_)
else:
a_ = Min(soln.lts, a_)
if a_ is not S.Infinity and a_ != b:
a = Max(a_, a)
elif b_ is not S.NegativeInfinity and b_ != a:
b = Min(b_, b)
else:
aux = And(aux, Or(*aux_))
return a, b, aux
conds = [process_conds(c) for c in disjuncts(cond)]
conds = [x for x in conds if x[2] != False]
conds.sort(key=lambda x: (x[0] - x[1], count_ops(x[2])))
if not conds:
raise IntegralTransformError('Mellin', f, 'no convergence found')
a, b, aux = conds[0]
return _simplify(F.subs(s, s_), simplify), (a, b), aux
class MellinTransform(IntegralTransform):
"""
Class representing unevaluated Mellin transforms.
For usage of this class, see the :class:`IntegralTransform` docstring.
For how to compute Mellin transforms, see the :func:`mellin_transform`
docstring.
"""
_name = 'Mellin'
def _compute_transform(self, f, x, s, **hints):
return _mellin_transform(f, x, s, **hints)
def _as_integral(self, f, x, s):
return Integral(f*x**(s - 1), (x, S.Zero, S.Infinity))
def _collapse_extra(self, extra):
a = []
b = []
cond = []
for (sa, sb), c in extra:
a += [sa]
b += [sb]
cond += [c]
res = (Max(*a), Min(*b)), And(*cond)
if (res[0][0] >= res[0][1]) == True or res[1] == False:
raise IntegralTransformError(
'Mellin', None, 'no combined convergence.')
return res
def mellin_transform(f, x, s, **hints):
r"""
Compute the Mellin transform `F(s)` of `f(x)`,
.. math :: F(s) = \int_0^\infty x^{s-1} f(x) \mathrm{d}x.
For all "sensible" functions, this converges absolutely in a strip
`a < \operatorname{Re}(s) < b`.
Explanation
===========
The Mellin transform is related via change of variables to the Fourier
transform, and also to the (bilateral) Laplace transform.
This function returns ``(F, (a, b), cond)``
where ``F`` is the Mellin transform of ``f``, ``(a, b)`` is the fundamental strip
(as above), and ``cond`` are auxiliary convergence conditions.
If the integral cannot be computed in closed form, this function returns
an unevaluated :class:`MellinTransform` object.
For a description of possible hints, refer to the docstring of
:func:`sympy.integrals.transforms.IntegralTransform.doit`. If ``noconds=False``,
then only `F` will be returned (i.e. not ``cond``, and also not the strip
``(a, b)``).
Examples
========
>>> from sympy import mellin_transform, exp
>>> from sympy.abc import x, s
>>> mellin_transform(exp(-x), x, s)
(gamma(s), (0, oo), True)
See Also
========
inverse_mellin_transform, laplace_transform, fourier_transform
hankel_transform, inverse_hankel_transform
"""
return MellinTransform(f, x, s).doit(**hints)
def _rewrite_sin(m_n, s, a, b):
"""
Re-write the sine function ``sin(m*s + n)`` as gamma functions, compatible
with the strip (a, b).
Return ``(gamma1, gamma2, fac)`` so that ``f == fac/(gamma1 * gamma2)``.
Examples
========
>>> from sympy.integrals.transforms import _rewrite_sin
>>> from sympy import pi, S
>>> from sympy.abc import s
>>> _rewrite_sin((pi, 0), s, 0, 1)
(gamma(s), gamma(1 - s), pi)
>>> _rewrite_sin((pi, 0), s, 1, 0)
(gamma(s - 1), gamma(2 - s), -pi)
>>> _rewrite_sin((pi, 0), s, -1, 0)
(gamma(s + 1), gamma(-s), -pi)
>>> _rewrite_sin((pi, pi/2), s, S(1)/2, S(3)/2)
(gamma(s - 1/2), gamma(3/2 - s), -pi)
>>> _rewrite_sin((pi, pi), s, 0, 1)
(gamma(s), gamma(1 - s), -pi)
>>> _rewrite_sin((2*pi, 0), s, 0, S(1)/2)
(gamma(2*s), gamma(1 - 2*s), pi)
>>> _rewrite_sin((2*pi, 0), s, S(1)/2, 1)
(gamma(2*s - 1), gamma(2 - 2*s), -pi)
"""
# (This is a separate function because it is moderately complicated,
# and I want to doctest it.)
# We want to use pi/sin(pi*x) = gamma(x)*gamma(1-x).
# But there is one comlication: the gamma functions determine the
# inegration contour in the definition of the G-function. Usually
# it would not matter if this is slightly shifted, unless this way
# we create an undefined function!
# So we try to write this in such a way that the gammas are
# eminently on the right side of the strip.
m, n = m_n
m = expand_mul(m/pi)
n = expand_mul(n/pi)
r = ceiling(-m*a - n.as_real_imag()[0]) # Don't use re(n), does not expand
return gamma(m*s + n + r), gamma(1 - n - r - m*s), (-1)**r*pi
class MellinTransformStripError(ValueError):
"""
Exception raised by _rewrite_gamma. Mainly for internal use.
"""
pass
def _rewrite_gamma(f, s, a, b):
"""
Try to rewrite the product f(s) as a product of gamma functions,
so that the inverse Mellin transform of f can be expressed as a meijer
G function.
Explanation
===========
Return (an, ap), (bm, bq), arg, exp, fac such that
G((an, ap), (bm, bq), arg/z**exp)*fac is the inverse Mellin transform of f(s).
Raises IntegralTransformError or MellinTransformStripError on failure.
It is asserted that f has no poles in the fundamental strip designated by
(a, b). One of a and b is allowed to be None. The fundamental strip is
important, because it determines the inversion contour.
This function can handle exponentials, linear factors, trigonometric
functions.
This is a helper function for inverse_mellin_transform that will not
attempt any transformations on f.
Examples
========
>>> from sympy.integrals.transforms import _rewrite_gamma
>>> from sympy.abc import s
>>> from sympy import oo
>>> _rewrite_gamma(s*(s+3)*(s-1), s, -oo, oo)
(([], [-3, 0, 1]), ([-2, 1, 2], []), 1, 1, -1)
>>> _rewrite_gamma((s-1)**2, s, -oo, oo)
(([], [1, 1]), ([2, 2], []), 1, 1, 1)
Importance of the fundamental strip:
>>> _rewrite_gamma(1/s, s, 0, oo)
(([1], []), ([], [0]), 1, 1, 1)
>>> _rewrite_gamma(1/s, s, None, oo)
(([1], []), ([], [0]), 1, 1, 1)
>>> _rewrite_gamma(1/s, s, 0, None)
(([1], []), ([], [0]), 1, 1, 1)
>>> _rewrite_gamma(1/s, s, -oo, 0)
(([], [1]), ([0], []), 1, 1, -1)
>>> _rewrite_gamma(1/s, s, None, 0)
(([], [1]), ([0], []), 1, 1, -1)
>>> _rewrite_gamma(1/s, s, -oo, None)
(([], [1]), ([0], []), 1, 1, -1)
>>> _rewrite_gamma(2**(-s+3), s, -oo, oo)
(([], []), ([], []), 1/2, 1, 8)
"""
# Our strategy will be as follows:
# 1) Guess a constant c such that the inversion integral should be
# performed wrt s'=c*s (instead of plain s). Write s for s'.
# 2) Process all factors, rewrite them independently as gamma functions in
# argument s, or exponentials of s.
# 3) Try to transform all gamma functions s.t. they have argument
# a+s or a-s.
# 4) Check that the resulting G function parameters are valid.
# 5) Combine all the exponentials.
a_, b_ = S([a, b])
def left(c, is_numer):
"""
Decide whether pole at c lies to the left of the fundamental strip.
"""
# heuristically, this is the best chance for us to solve the inequalities
c = expand(re(c))
if a_ is None and b_ is S.Infinity:
return True
if a_ is None:
return c < b_
if b_ is None:
return c <= a_
if (c >= b_) == True:
return False
if (c <= a_) == True:
return True
if is_numer:
return None
if a_.free_symbols or b_.free_symbols or c.free_symbols:
return None # XXX
#raise IntegralTransformError('Inverse Mellin', f,
# 'Could not determine position of singularity %s'
# ' relative to fundamental strip' % c)
raise MellinTransformStripError('Pole inside critical strip?')
# 1)
s_multipliers = []
for g in f.atoms(gamma):
if not g.has(s):
continue
arg = g.args[0]
if arg.is_Add:
arg = arg.as_independent(s)[1]
coeff, _ = arg.as_coeff_mul(s)
s_multipliers += [coeff]
for g in f.atoms(sin, cos, tan, cot):
if not g.has(s):
continue
arg = g.args[0]
if arg.is_Add:
arg = arg.as_independent(s)[1]
coeff, _ = arg.as_coeff_mul(s)
s_multipliers += [coeff/pi]
s_multipliers = [Abs(x) if x.is_extended_real else x for x in s_multipliers]
common_coefficient = S.One
for x in s_multipliers:
if not x.is_Rational:
common_coefficient = x
break
s_multipliers = [x/common_coefficient for x in s_multipliers]
if not (all(x.is_Rational for x in s_multipliers) and
common_coefficient.is_extended_real):
raise IntegralTransformError("Gamma", None, "Nonrational multiplier")
s_multiplier = common_coefficient/reduce(ilcm, [S(x.q)
for x in s_multipliers], S.One)
if s_multiplier == common_coefficient:
if len(s_multipliers) == 0:
s_multiplier = common_coefficient
else:
s_multiplier = common_coefficient \
*reduce(igcd, [S(x.p) for x in s_multipliers])
f = f.subs(s, s/s_multiplier)
fac = S.One/s_multiplier
exponent = S.One/s_multiplier
if a_ is not None:
a_ *= s_multiplier
if b_ is not None:
b_ *= s_multiplier
# 2)
numer, denom = f.as_numer_denom()
numer = Mul.make_args(numer)
denom = Mul.make_args(denom)
args = list(zip(numer, repeat(True))) + list(zip(denom, repeat(False)))
facs = []
dfacs = []
# *_gammas will contain pairs (a, c) representing Gamma(a*s + c)
numer_gammas = []
denom_gammas = []
# exponentials will contain bases for exponentials of s
exponentials = []
def exception(fact):
return IntegralTransformError("Inverse Mellin", f, "Unrecognised form '%s'." % fact)
while args:
fact, is_numer = args.pop()
if is_numer:
ugammas, lgammas = numer_gammas, denom_gammas
ufacs = facs
else:
ugammas, lgammas = denom_gammas, numer_gammas
ufacs = dfacs
def linear_arg(arg):
""" Test if arg is of form a*s+b, raise exception if not. """
if not arg.is_polynomial(s):
raise exception(fact)
p = Poly(arg, s)
if p.degree() != 1:
raise exception(fact)
return p.all_coeffs()
# constants
if not fact.has(s):
ufacs += [fact]
# exponentials
elif fact.is_Pow or isinstance(fact, exp):
if fact.is_Pow:
base = fact.base
exp_ = fact.exp
else:
base = exp_polar(1)
exp_ = fact.exp
if exp_.is_Integer:
cond = is_numer
if exp_ < 0:
cond = not cond
args += [(base, cond)]*Abs(exp_)
continue
elif not base.has(s):
a, b = linear_arg(exp_)
if not is_numer:
base = 1/base
exponentials += [base**a]
facs += [base**b]
else:
raise exception(fact)
# linear factors
elif fact.is_polynomial(s):
p = Poly(fact, s)
if p.degree() != 1:
# We completely factor the poly. For this we need the roots.
# Now roots() only works in some cases (low degree), and CRootOf
# only works without parameters. So try both...
coeff = p.LT()[1]
rs = roots(p, s)
if len(rs) != p.degree():
rs = CRootOf.all_roots(p)
ufacs += [coeff]
args += [(s - c, is_numer) for c in rs]
continue
a, c = p.all_coeffs()
ufacs += [a]
c /= -a
# Now need to convert s - c
if left(c, is_numer):
ugammas += [(S.One, -c + 1)]
lgammas += [(S.One, -c)]
else:
ufacs += [-1]
ugammas += [(S.NegativeOne, c + 1)]
lgammas += [(S.NegativeOne, c)]
elif isinstance(fact, gamma):
a, b = linear_arg(fact.args[0])
if is_numer:
if (a > 0 and (left(-b/a, is_numer) == False)) or \
(a < 0 and (left(-b/a, is_numer) == True)):
raise NotImplementedError(
'Gammas partially over the strip.')
ugammas += [(a, b)]
elif isinstance(fact, sin):
# We try to re-write all trigs as gammas. This is not in
# general the best strategy, since sometimes this is impossible,
# but rewriting as exponentials would work. However trig functions
# in inverse mellin transforms usually all come from simplifying
# gamma terms, so this should work.
a = fact.args[0]
if is_numer:
# No problem with the poles.
gamma1, gamma2, fac_ = gamma(a/pi), gamma(1 - a/pi), pi
else:
gamma1, gamma2, fac_ = _rewrite_sin(linear_arg(a), s, a_, b_)
args += [(gamma1, not is_numer), (gamma2, not is_numer)]
ufacs += [fac_]
elif isinstance(fact, tan):
a = fact.args[0]
args += [(sin(a, evaluate=False), is_numer),
(sin(pi/2 - a, evaluate=False), not is_numer)]
elif isinstance(fact, cos):
a = fact.args[0]
args += [(sin(pi/2 - a, evaluate=False), is_numer)]
elif isinstance(fact, cot):
a = fact.args[0]
args += [(sin(pi/2 - a, evaluate=False), is_numer),
(sin(a, evaluate=False), not is_numer)]
else:
raise exception(fact)
fac *= Mul(*facs)/Mul(*dfacs)
# 3)
an, ap, bm, bq = [], [], [], []
for gammas, plus, minus, is_numer in [(numer_gammas, an, bm, True),
(denom_gammas, bq, ap, False)]:
while gammas:
a, c = gammas.pop()
if a != -1 and a != +1:
# We use the gamma function multiplication theorem.
p = Abs(S(a))
newa = a/p
newc = c/p
if not a.is_Integer:
raise TypeError("a is not an integer")
for k in range(p):
gammas += [(newa, newc + k/p)]
if is_numer:
fac *= (2*pi)**((1 - p)/2) * p**(c - S.Half)
exponentials += [p**a]
else:
fac /= (2*pi)**((1 - p)/2) * p**(c - S.Half)
exponentials += [p**(-a)]
continue
if a == +1:
plus.append(1 - c)
else:
minus.append(c)
# 4)
# TODO
# 5)
arg = Mul(*exponentials)
# for testability, sort the arguments
an.sort(key=default_sort_key)
ap.sort(key=default_sort_key)
bm.sort(key=default_sort_key)
bq.sort(key=default_sort_key)
return (an, ap), (bm, bq), arg, exponent, fac
@_noconds_(True)
def _inverse_mellin_transform(F, s, x_, strip, as_meijerg=False):
""" A helper for the real inverse_mellin_transform function, this one here
assumes x to be real and positive. """
x = _dummy('t', 'inverse-mellin-transform', F, positive=True)
# Actually, we won't try integration at all. Instead we use the definition
# of the Meijer G function as a fairly general inverse mellin transform.
F = F.rewrite(gamma)
for g in [factor(F), expand_mul(F), expand(F)]:
if g.is_Add:
# do all terms separately
ress = [_inverse_mellin_transform(G, s, x, strip, as_meijerg,
noconds=False)
for G in g.args]
conds = [p[1] for p in ress]
ress = [p[0] for p in ress]
res = Add(*ress)
if not as_meijerg:
res = factor(res, gens=res.atoms(Heaviside))
return res.subs(x, x_), And(*conds)
try:
a, b, C, e, fac = _rewrite_gamma(g, s, strip[0], strip[1])
except IntegralTransformError:
continue
try:
G = meijerg(a, b, C/x**e)
except ValueError:
continue
if as_meijerg:
h = G
else:
try:
from sympy.simplify import hyperexpand
h = hyperexpand(G)
except NotImplementedError:
raise IntegralTransformError(
'Inverse Mellin', F, 'Could not calculate integral')
if h.is_Piecewise and len(h.args) == 3:
# XXX we break modularity here!
h = Heaviside(x - Abs(C))*h.args[0].args[0] \
+ Heaviside(Abs(C) - x)*h.args[1].args[0]
# We must ensure that the integral along the line we want converges,
# and return that value.
# See [L], 5.2
cond = [Abs(arg(G.argument)) < G.delta*pi]
# Note: we allow ">=" here, this corresponds to convergence if we let
# limits go to oo symmetrically. ">" corresponds to absolute convergence.
cond += [And(Or(len(G.ap) != len(G.bq), 0 >= re(G.nu) + 1),
Abs(arg(G.argument)) == G.delta*pi)]
cond = Or(*cond)
if cond == False:
raise IntegralTransformError(
'Inverse Mellin', F, 'does not converge')
return (h*fac).subs(x, x_), cond
raise IntegralTransformError('Inverse Mellin', F, '')
_allowed = None
class InverseMellinTransform(IntegralTransform):
"""
Class representing unevaluated inverse Mellin transforms.
For usage of this class, see the :class:`IntegralTransform` docstring.
For how to compute inverse Mellin transforms, see the
:func:`inverse_mellin_transform` docstring.
"""
_name = 'Inverse Mellin'
_none_sentinel = Dummy('None')
_c = Dummy('c')
def __new__(cls, F, s, x, a, b, **opts):
if a is None:
a = InverseMellinTransform._none_sentinel
if b is None:
b = InverseMellinTransform._none_sentinel
return IntegralTransform.__new__(cls, F, s, x, a, b, **opts)
@property
def fundamental_strip(self):
a, b = self.args[3], self.args[4]
if a is InverseMellinTransform._none_sentinel:
a = None
if b is InverseMellinTransform._none_sentinel:
b = None
return a, b
def _compute_transform(self, F, s, x, **hints):
# IntegralTransform's doit will cause this hint to exist, but
# InverseMellinTransform should ignore it
hints.pop('simplify', True)
global _allowed
if _allowed is None:
_allowed = {
exp, gamma, sin, cos, tan, cot, cosh, sinh, tanh, coth,
factorial, rf}
for f in postorder_traversal(F):
if f.is_Function and f.has(s) and f.func not in _allowed:
raise IntegralTransformError('Inverse Mellin', F,
'Component %s not recognised.' % f)
strip = self.fundamental_strip
return _inverse_mellin_transform(F, s, x, strip, **hints)
def _as_integral(self, F, s, x):
c = self.__class__._c
return Integral(F*x**(-s), (s, c - S.ImaginaryUnit*S.Infinity, c +
S.ImaginaryUnit*S.Infinity))/(2*S.Pi*S.ImaginaryUnit)
def inverse_mellin_transform(F, s, x, strip, **hints):
r"""
Compute the inverse Mellin transform of `F(s)` over the fundamental
strip given by ``strip=(a, b)``.
Explanation
===========
This can be defined as
.. math:: f(x) = \frac{1}{2\pi i} \int_{c - i\infty}^{c + i\infty} x^{-s} F(s) \mathrm{d}s,
for any `c` in the fundamental strip. Under certain regularity
conditions on `F` and/or `f`,
this recovers `f` from its Mellin transform `F`
(and vice versa), for positive real `x`.
One of `a` or `b` may be passed as ``None``; a suitable `c` will be
inferred.
If the integral cannot be computed in closed form, this function returns
an unevaluated :class:`InverseMellinTransform` object.
Note that this function will assume x to be positive and real, regardless
of the SymPy assumptions!
For a description of possible hints, refer to the docstring of
:func:`sympy.integrals.transforms.IntegralTransform.doit`.
Examples
========
>>> from sympy import inverse_mellin_transform, oo, gamma
>>> from sympy.abc import x, s
>>> inverse_mellin_transform(gamma(s), s, x, (0, oo))
exp(-x)
The fundamental strip matters:
>>> f = 1/(s**2 - 1)
>>> inverse_mellin_transform(f, s, x, (-oo, -1))
x*(1 - 1/x**2)*Heaviside(x - 1)/2
>>> inverse_mellin_transform(f, s, x, (-1, 1))
-x*Heaviside(1 - x)/2 - Heaviside(x - 1)/(2*x)
>>> inverse_mellin_transform(f, s, x, (1, oo))
(1/2 - x**2/2)*Heaviside(1 - x)/x
See Also
========
mellin_transform
hankel_transform, inverse_hankel_transform
"""
return InverseMellinTransform(F, s, x, strip[0], strip[1]).doit(**hints)
##########################################################################
# Fourier Transform
##########################################################################
@_noconds_(True)
def _fourier_transform(f, x, k, a, b, name, simplify=True):
r"""
Compute a general Fourier-type transform
.. math::
F(k) = a \int_{-\infty}^{\infty} e^{bixk} f(x)\, dx.
For suitable choice of *a* and *b*, this reduces to the standard Fourier
and inverse Fourier transforms.
"""
F = integrate(a*f*exp(b*S.ImaginaryUnit*x*k), (x, S.NegativeInfinity, S.Infinity))
if not F.has(Integral):
return _simplify(F, simplify), S.true
integral_f = integrate(f, (x, S.NegativeInfinity, S.Infinity))
if integral_f in (S.NegativeInfinity, S.Infinity, S.NaN) or integral_f.has(Integral):
raise IntegralTransformError(name, f, 'function not integrable on real axis')
if not F.is_Piecewise:
raise IntegralTransformError(name, f, 'could not compute integral')
F, cond = F.args[0]
if F.has(Integral):
raise IntegralTransformError(name, f, 'integral in unexpected form')
return _simplify(F, simplify), cond
class FourierTypeTransform(IntegralTransform):
""" Base class for Fourier transforms."""
def a(self):
raise NotImplementedError(
"Class %s must implement a(self) but does not" % self.__class__)
def b(self):
raise NotImplementedError(
"Class %s must implement b(self) but does not" % self.__class__)
def _compute_transform(self, f, x, k, **hints):
return _fourier_transform(f, x, k,
self.a(), self.b(),
self.__class__._name, **hints)
def _as_integral(self, f, x, k):
a = self.a()
b = self.b()
return Integral(a*f*exp(b*S.ImaginaryUnit*x*k), (x, S.NegativeInfinity, S.Infinity))
class FourierTransform(FourierTypeTransform):
"""
Class representing unevaluated Fourier transforms.
For usage of this class, see the :class:`IntegralTransform` docstring.
For how to compute Fourier transforms, see the :func:`fourier_transform`
docstring.
"""
_name = 'Fourier'
def a(self):
return 1
def b(self):
return -2*S.Pi
def fourier_transform(f, x, k, **hints):
r"""
Compute the unitary, ordinary-frequency Fourier transform of ``f``, defined
as
.. math:: F(k) = \int_{-\infty}^\infty f(x) e^{-2\pi i x k} \mathrm{d} x.
Explanation
===========
If the transform cannot be computed in closed form, this
function returns an unevaluated :class:`FourierTransform` object.
For other Fourier transform conventions, see the function
:func:`sympy.integrals.transforms._fourier_transform`.
For a description of possible hints, refer to the docstring of
:func:`sympy.integrals.transforms.IntegralTransform.doit`.
Note that for this transform, by default ``noconds=True``.
Examples
========
>>> from sympy import fourier_transform, exp
>>> from sympy.abc import x, k
>>> fourier_transform(exp(-x**2), x, k)
sqrt(pi)*exp(-pi**2*k**2)
>>> fourier_transform(exp(-x**2), x, k, noconds=False)
(sqrt(pi)*exp(-pi**2*k**2), True)
See Also
========
inverse_fourier_transform
sine_transform, inverse_sine_transform
cosine_transform, inverse_cosine_transform
hankel_transform, inverse_hankel_transform
mellin_transform, laplace_transform
"""
return FourierTransform(f, x, k).doit(**hints)
class InverseFourierTransform(FourierTypeTransform):
"""
Class representing unevaluated inverse Fourier transforms.
For usage of this class, see the :class:`IntegralTransform` docstring.
For how to compute inverse Fourier transforms, see the
:func:`inverse_fourier_transform` docstring.
"""
_name = 'Inverse Fourier'
def a(self):
return 1
def b(self):
return 2*S.Pi
def inverse_fourier_transform(F, k, x, **hints):
r"""
Compute the unitary, ordinary-frequency inverse Fourier transform of `F`,
defined as
.. math:: f(x) = \int_{-\infty}^\infty F(k) e^{2\pi i x k} \mathrm{d} k.
Explanation
===========
If the transform cannot be computed in closed form, this
function returns an unevaluated :class:`InverseFourierTransform` object.
For other Fourier transform conventions, see the function
:func:`sympy.integrals.transforms._fourier_transform`.
For a description of possible hints, refer to the docstring of
:func:`sympy.integrals.transforms.IntegralTransform.doit`.
Note that for this transform, by default ``noconds=True``.
Examples
========
>>> from sympy import inverse_fourier_transform, exp, sqrt, pi
>>> from sympy.abc import x, k
>>> inverse_fourier_transform(sqrt(pi)*exp(-(pi*k)**2), k, x)
exp(-x**2)
>>> inverse_fourier_transform(sqrt(pi)*exp(-(pi*k)**2), k, x, noconds=False)
(exp(-x**2), True)
See Also
========
fourier_transform
sine_transform, inverse_sine_transform
cosine_transform, inverse_cosine_transform
hankel_transform, inverse_hankel_transform
mellin_transform, laplace_transform
"""
return InverseFourierTransform(F, k, x).doit(**hints)
##########################################################################
# Fourier Sine and Cosine Transform
##########################################################################
@_noconds_(True)
def _sine_cosine_transform(f, x, k, a, b, K, name, simplify=True):
"""
Compute a general sine or cosine-type transform
F(k) = a int_0^oo b*sin(x*k) f(x) dx.
F(k) = a int_0^oo b*cos(x*k) f(x) dx.
For suitable choice of a and b, this reduces to the standard sine/cosine
and inverse sine/cosine transforms.
"""
F = integrate(a*f*K(b*x*k), (x, S.Zero, S.Infinity))
if not F.has(Integral):
return _simplify(F, simplify), S.true
if not F.is_Piecewise:
raise IntegralTransformError(name, f, 'could not compute integral')
F, cond = F.args[0]
if F.has(Integral):
raise IntegralTransformError(name, f, 'integral in unexpected form')
return _simplify(F, simplify), cond
class SineCosineTypeTransform(IntegralTransform):
"""
Base class for sine and cosine transforms.
Specify cls._kern.
"""
def a(self):
raise NotImplementedError(
"Class %s must implement a(self) but does not" % self.__class__)
def b(self):
raise NotImplementedError(
"Class %s must implement b(self) but does not" % self.__class__)
def _compute_transform(self, f, x, k, **hints):
return _sine_cosine_transform(f, x, k,
self.a(), self.b(),
self.__class__._kern,
self.__class__._name, **hints)
def _as_integral(self, f, x, k):
a = self.a()
b = self.b()
K = self.__class__._kern
return Integral(a*f*K(b*x*k), (x, S.Zero, S.Infinity))
class SineTransform(SineCosineTypeTransform):
"""
Class representing unevaluated sine transforms.
For usage of this class, see the :class:`IntegralTransform` docstring.
For how to compute sine transforms, see the :func:`sine_transform`
docstring.
"""
_name = 'Sine'
_kern = sin
def a(self):
return sqrt(2)/sqrt(pi)
def b(self):
return S.One
def sine_transform(f, x, k, **hints):
r"""
Compute the unitary, ordinary-frequency sine transform of `f`, defined
as
.. math:: F(k) = \sqrt{\frac{2}{\pi}} \int_{0}^\infty f(x) \sin(2\pi x k) \mathrm{d} x.
Explanation
===========
If the transform cannot be computed in closed form, this
function returns an unevaluated :class:`SineTransform` object.
For a description of possible hints, refer to the docstring of
:func:`sympy.integrals.transforms.IntegralTransform.doit`.
Note that for this transform, by default ``noconds=True``.
Examples
========
>>> from sympy import sine_transform, exp
>>> from sympy.abc import x, k, a
>>> sine_transform(x*exp(-a*x**2), x, k)
sqrt(2)*k*exp(-k**2/(4*a))/(4*a**(3/2))
>>> sine_transform(x**(-a), x, k)
2**(1/2 - a)*k**(a - 1)*gamma(1 - a/2)/gamma(a/2 + 1/2)
See Also
========
fourier_transform, inverse_fourier_transform
inverse_sine_transform
cosine_transform, inverse_cosine_transform
hankel_transform, inverse_hankel_transform
mellin_transform, laplace_transform
"""
return SineTransform(f, x, k).doit(**hints)
class InverseSineTransform(SineCosineTypeTransform):
"""
Class representing unevaluated inverse sine transforms.
For usage of this class, see the :class:`IntegralTransform` docstring.
For how to compute inverse sine transforms, see the
:func:`inverse_sine_transform` docstring.
"""
_name = 'Inverse Sine'
_kern = sin
def a(self):
return sqrt(2)/sqrt(pi)
def b(self):
return S.One
def inverse_sine_transform(F, k, x, **hints):
r"""
Compute the unitary, ordinary-frequency inverse sine transform of `F`,
defined as
.. math:: f(x) = \sqrt{\frac{2}{\pi}} \int_{0}^\infty F(k) \sin(2\pi x k) \mathrm{d} k.
Explanation
===========
If the transform cannot be computed in closed form, this
function returns an unevaluated :class:`InverseSineTransform` object.
For a description of possible hints, refer to the docstring of
:func:`sympy.integrals.transforms.IntegralTransform.doit`.
Note that for this transform, by default ``noconds=True``.
Examples
========
>>> from sympy import inverse_sine_transform, exp, sqrt, gamma
>>> from sympy.abc import x, k, a
>>> inverse_sine_transform(2**((1-2*a)/2)*k**(a - 1)*
... gamma(-a/2 + 1)/gamma((a+1)/2), k, x)
x**(-a)
>>> inverse_sine_transform(sqrt(2)*k*exp(-k**2/(4*a))/(4*sqrt(a)**3), k, x)
x*exp(-a*x**2)
See Also
========
fourier_transform, inverse_fourier_transform
sine_transform
cosine_transform, inverse_cosine_transform
hankel_transform, inverse_hankel_transform
mellin_transform, laplace_transform
"""
return InverseSineTransform(F, k, x).doit(**hints)
class CosineTransform(SineCosineTypeTransform):
"""
Class representing unevaluated cosine transforms.
For usage of this class, see the :class:`IntegralTransform` docstring.
For how to compute cosine transforms, see the :func:`cosine_transform`
docstring.
"""
_name = 'Cosine'
_kern = cos
def a(self):
return sqrt(2)/sqrt(pi)
def b(self):
return S.One
def cosine_transform(f, x, k, **hints):
r"""
Compute the unitary, ordinary-frequency cosine transform of `f`, defined
as
.. math:: F(k) = \sqrt{\frac{2}{\pi}} \int_{0}^\infty f(x) \cos(2\pi x k) \mathrm{d} x.
Explanation
===========
If the transform cannot be computed in closed form, this
function returns an unevaluated :class:`CosineTransform` object.
For a description of possible hints, refer to the docstring of
:func:`sympy.integrals.transforms.IntegralTransform.doit`.
Note that for this transform, by default ``noconds=True``.
Examples
========
>>> from sympy import cosine_transform, exp, sqrt, cos
>>> from sympy.abc import x, k, a
>>> cosine_transform(exp(-a*x), x, k)
sqrt(2)*a/(sqrt(pi)*(a**2 + k**2))
>>> cosine_transform(exp(-a*sqrt(x))*cos(a*sqrt(x)), x, k)
a*exp(-a**2/(2*k))/(2*k**(3/2))
See Also
========
fourier_transform, inverse_fourier_transform,
sine_transform, inverse_sine_transform
inverse_cosine_transform
hankel_transform, inverse_hankel_transform
mellin_transform, laplace_transform
"""
return CosineTransform(f, x, k).doit(**hints)
class InverseCosineTransform(SineCosineTypeTransform):
"""
Class representing unevaluated inverse cosine transforms.
For usage of this class, see the :class:`IntegralTransform` docstring.
For how to compute inverse cosine transforms, see the
:func:`inverse_cosine_transform` docstring.
"""
_name = 'Inverse Cosine'
_kern = cos
def a(self):
return sqrt(2)/sqrt(pi)
def b(self):
return S.One
def inverse_cosine_transform(F, k, x, **hints):
r"""
Compute the unitary, ordinary-frequency inverse cosine transform of `F`,
defined as
.. math:: f(x) = \sqrt{\frac{2}{\pi}} \int_{0}^\infty F(k) \cos(2\pi x k) \mathrm{d} k.
Explanation
===========
If the transform cannot be computed in closed form, this
function returns an unevaluated :class:`InverseCosineTransform` object.
For a description of possible hints, refer to the docstring of
:func:`sympy.integrals.transforms.IntegralTransform.doit`.
Note that for this transform, by default ``noconds=True``.
Examples
========
>>> from sympy import inverse_cosine_transform, sqrt, pi
>>> from sympy.abc import x, k, a
>>> inverse_cosine_transform(sqrt(2)*a/(sqrt(pi)*(a**2 + k**2)), k, x)
exp(-a*x)
>>> inverse_cosine_transform(1/sqrt(k), k, x)
1/sqrt(x)
See Also
========
fourier_transform, inverse_fourier_transform,
sine_transform, inverse_sine_transform
cosine_transform
hankel_transform, inverse_hankel_transform
mellin_transform, laplace_transform
"""
return InverseCosineTransform(F, k, x).doit(**hints)
##########################################################################
# Hankel Transform
##########################################################################
@_noconds_(True)
def _hankel_transform(f, r, k, nu, name, simplify=True):
r"""
Compute a general Hankel transform
.. math:: F_\nu(k) = \int_{0}^\infty f(r) J_\nu(k r) r \mathrm{d} r.
"""
F = integrate(f*besselj(nu, k*r)*r, (r, S.Zero, S.Infinity))
if not F.has(Integral):
return _simplify(F, simplify), S.true
if not F.is_Piecewise:
raise IntegralTransformError(name, f, 'could not compute integral')
F, cond = F.args[0]
if F.has(Integral):
raise IntegralTransformError(name, f, 'integral in unexpected form')
return _simplify(F, simplify), cond
class HankelTypeTransform(IntegralTransform):
"""
Base class for Hankel transforms.
"""
def doit(self, **hints):
return self._compute_transform(self.function,
self.function_variable,
self.transform_variable,
self.args[3],
**hints)
def _compute_transform(self, f, r, k, nu, **hints):
return _hankel_transform(f, r, k, nu, self._name, **hints)
def _as_integral(self, f, r, k, nu):
return Integral(f*besselj(nu, k*r)*r, (r, S.Zero, S.Infinity))
@property
def as_integral(self):
return self._as_integral(self.function,
self.function_variable,
self.transform_variable,
self.args[3])
class HankelTransform(HankelTypeTransform):
"""
Class representing unevaluated Hankel transforms.
For usage of this class, see the :class:`IntegralTransform` docstring.
For how to compute Hankel transforms, see the :func:`hankel_transform`
docstring.
"""
_name = 'Hankel'
def hankel_transform(f, r, k, nu, **hints):
r"""
Compute the Hankel transform of `f`, defined as
.. math:: F_\nu(k) = \int_{0}^\infty f(r) J_\nu(k r) r \mathrm{d} r.
Explanation
===========
If the transform cannot be computed in closed form, this
function returns an unevaluated :class:`HankelTransform` object.
For a description of possible hints, refer to the docstring of
:func:`sympy.integrals.transforms.IntegralTransform.doit`.
Note that for this transform, by default ``noconds=True``.
Examples
========
>>> from sympy import hankel_transform, inverse_hankel_transform
>>> from sympy import exp
>>> from sympy.abc import r, k, m, nu, a
>>> ht = hankel_transform(1/r**m, r, k, nu)
>>> ht
2*k**(m - 2)*gamma(-m/2 + nu/2 + 1)/(2**m*gamma(m/2 + nu/2))
>>> inverse_hankel_transform(ht, k, r, nu)
r**(-m)
>>> ht = hankel_transform(exp(-a*r), r, k, 0)
>>> ht
a/(k**3*(a**2/k**2 + 1)**(3/2))
>>> inverse_hankel_transform(ht, k, r, 0)
exp(-a*r)
See Also
========
fourier_transform, inverse_fourier_transform
sine_transform, inverse_sine_transform
cosine_transform, inverse_cosine_transform
inverse_hankel_transform
mellin_transform, laplace_transform
"""
return HankelTransform(f, r, k, nu).doit(**hints)
class InverseHankelTransform(HankelTypeTransform):
"""
Class representing unevaluated inverse Hankel transforms.
For usage of this class, see the :class:`IntegralTransform` docstring.
For how to compute inverse Hankel transforms, see the
:func:`inverse_hankel_transform` docstring.
"""
_name = 'Inverse Hankel'
def inverse_hankel_transform(F, k, r, nu, **hints):
r"""
Compute the inverse Hankel transform of `F` defined as
.. math:: f(r) = \int_{0}^\infty F_\nu(k) J_\nu(k r) k \mathrm{d} k.
Explanation
===========
If the transform cannot be computed in closed form, this
function returns an unevaluated :class:`InverseHankelTransform` object.
For a description of possible hints, refer to the docstring of
:func:`sympy.integrals.transforms.IntegralTransform.doit`.
Note that for this transform, by default ``noconds=True``.
Examples
========
>>> from sympy import hankel_transform, inverse_hankel_transform
>>> from sympy import exp
>>> from sympy.abc import r, k, m, nu, a
>>> ht = hankel_transform(1/r**m, r, k, nu)
>>> ht
2*k**(m - 2)*gamma(-m/2 + nu/2 + 1)/(2**m*gamma(m/2 + nu/2))
>>> inverse_hankel_transform(ht, k, r, nu)
r**(-m)
>>> ht = hankel_transform(exp(-a*r), r, k, 0)
>>> ht
a/(k**3*(a**2/k**2 + 1)**(3/2))
>>> inverse_hankel_transform(ht, k, r, 0)
exp(-a*r)
See Also
========
fourier_transform, inverse_fourier_transform
sine_transform, inverse_sine_transform
cosine_transform, inverse_cosine_transform
hankel_transform
mellin_transform, laplace_transform
"""
return InverseHankelTransform(F, k, r, nu).doit(**hints)
##########################################################################
# Laplace Transform
##########################################################################
# Stub classes and functions that used to be here
import sympy.integrals.laplace as _laplace
LaplaceTransform = _laplace.LaplaceTransform
laplace_transform = _laplace.laplace_transform
laplace_correspondence = _laplace.laplace_correspondence
laplace_initial_conds = _laplace.laplace_initial_conds
InverseLaplaceTransform = _laplace.InverseLaplaceTransform
inverse_laplace_transform = _laplace.inverse_laplace_transform
PK ]ZZZ��K+ K+ sympy/integrals/trigonometry.pyfrom sympy.core import cacheit, Dummy, Ne, Integer, Rational, S, Wild
from sympy.functions import binomial, sin, cos, Piecewise, Abs
from .integrals import integrate
# TODO sin(a*x)*cos(b*x) -> sin((a+b)x) + sin((a-b)x) ?
# creating, each time, Wild's and sin/cos/Mul is expensive. Also, our match &
# subs are very slow when not cached, and if we create Wild each time, we
# effectively block caching.
#
# so we cache the pattern
# need to use a function instead of lamda since hash of lambda changes on
# each call to _pat_sincos
def _integer_instance(n):
return isinstance(n, Integer)
@cacheit
def _pat_sincos(x):
a = Wild('a', exclude=[x])
n, m = [Wild(s, exclude=[x], properties=[_integer_instance])
for s in 'nm']
pat = sin(a*x)**n * cos(a*x)**m
return pat, a, n, m
_u = Dummy('u')
def trigintegrate(f, x, conds='piecewise'):
"""
Integrate f = Mul(trig) over x.
Examples
========
>>> from sympy import sin, cos, tan, sec
>>> from sympy.integrals.trigonometry import trigintegrate
>>> from sympy.abc import x
>>> trigintegrate(sin(x)*cos(x), x)
sin(x)**2/2
>>> trigintegrate(sin(x)**2, x)
x/2 - sin(x)*cos(x)/2
>>> trigintegrate(tan(x)*sec(x), x)
1/cos(x)
>>> trigintegrate(sin(x)*tan(x), x)
-log(sin(x) - 1)/2 + log(sin(x) + 1)/2 - sin(x)
References
==========
.. [1] https://en.wikibooks.org/wiki/Calculus/Integration_techniques
See Also
========
sympy.integrals.integrals.Integral.doit
sympy.integrals.integrals.Integral
"""
pat, a, n, m = _pat_sincos(x)
f = f.rewrite('sincos')
M = f.match(pat)
if M is None:
return
n, m = M[n], M[m]
if n.is_zero and m.is_zero:
return x
zz = x if n.is_zero else S.Zero
a = M[a]
if n.is_odd or m.is_odd:
u = _u
n_, m_ = n.is_odd, m.is_odd
# take smallest n or m -- to choose simplest substitution
if n_ and m_:
# Make sure to choose the positive one
# otherwise an incorrect integral can occur.
if n < 0 and m > 0:
m_ = True
n_ = False
elif m < 0 and n > 0:
n_ = True
m_ = False
# Both are negative so choose the smallest n or m
# in absolute value for simplest substitution.
elif (n < 0 and m < 0):
n_ = n > m
m_ = not (n > m)
# Both n and m are odd and positive
else:
n_ = (n < m) # NB: careful here, one of the
m_ = not (n < m) # conditions *must* be true
# n m u=C (n-1)/2 m
# S(x) * C(x) dx --> -(1-u^2) * u du
if n_:
ff = -(1 - u**2)**((n - 1)/2) * u**m
uu = cos(a*x)
# n m u=S n (m-1)/2
# S(x) * C(x) dx --> u * (1-u^2) du
elif m_:
ff = u**n * (1 - u**2)**((m - 1)/2)
uu = sin(a*x)
fi = integrate(ff, u) # XXX cyclic deps
fx = fi.subs(u, uu)
if conds == 'piecewise':
return Piecewise((fx / a, Ne(a, 0)), (zz, True))
return fx / a
# n & m are both even
#
# 2k 2m 2l 2l
# we transform S (x) * C (x) into terms with only S (x) or C (x)
#
# example:
# 100 4 100 2 2 100 4 2
# S (x) * C (x) = S (x) * (1-S (x)) = S (x) * (1 + S (x) - 2*S (x))
#
# 104 102 100
# = S (x) - 2*S (x) + S (x)
# 2k
# then S is integrated with recursive formula
# take largest n or m -- to choose simplest substitution
n_ = (Abs(n) > Abs(m))
m_ = (Abs(m) > Abs(n))
res = S.Zero
if n_:
# 2k 2 k i 2i
# C = (1 - S ) = sum(i, (-) * B(k, i) * S )
if m > 0:
for i in range(0, m//2 + 1):
res += (S.NegativeOne**i * binomial(m//2, i) *
_sin_pow_integrate(n + 2*i, x))
elif m == 0:
res = _sin_pow_integrate(n, x)
else:
# m < 0 , |n| > |m|
# /
# |
# | m n
# | cos (x) sin (x) dx =
# |
# |
#/
# /
# |
# -1 m+1 n-1 n - 1 | m+2 n-2
# ________ cos (x) sin (x) + _______ | cos (x) sin (x) dx
# |
# m + 1 m + 1 |
# /
res = (Rational(-1, m + 1) * cos(x)**(m + 1) * sin(x)**(n - 1) +
Rational(n - 1, m + 1) *
trigintegrate(cos(x)**(m + 2)*sin(x)**(n - 2), x))
elif m_:
# 2k 2 k i 2i
# S = (1 - C ) = sum(i, (-) * B(k, i) * C )
if n > 0:
# / /
# | |
# | m n | -m n
# | cos (x)*sin (x) dx or | cos (x) * sin (x) dx
# | |
# / /
#
# |m| > |n| ; m, n >0 ; m, n belong to Z - {0}
# n 2
# sin (x) term is expanded here in terms of cos (x),
# and then integrated.
#
for i in range(0, n//2 + 1):
res += (S.NegativeOne**i * binomial(n//2, i) *
_cos_pow_integrate(m + 2*i, x))
elif n == 0:
# /
# |
# | 1
# | _ _ _
# | m
# | cos (x)
# /
#
res = _cos_pow_integrate(m, x)
else:
# n < 0 , |m| > |n|
# /
# |
# | m n
# | cos (x) sin (x) dx =
# |
# |
#/
# /
# |
# 1 m-1 n+1 m - 1 | m-2 n+2
# _______ cos (x) sin (x) + _______ | cos (x) sin (x) dx
# |
# n + 1 n + 1 |
# /
res = (Rational(1, n + 1) * cos(x)**(m - 1)*sin(x)**(n + 1) +
Rational(m - 1, n + 1) *
trigintegrate(cos(x)**(m - 2)*sin(x)**(n + 2), x))
else:
if m == n:
##Substitute sin(2x)/2 for sin(x)cos(x) and then Integrate.
res = integrate((sin(2*x)*S.Half)**m, x)
elif (m == -n):
if n < 0:
# Same as the scheme described above.
# the function argument to integrate in the end will
# be 1, this cannot be integrated by trigintegrate.
# Hence use sympy.integrals.integrate.
res = (Rational(1, n + 1) * cos(x)**(m - 1) * sin(x)**(n + 1) +
Rational(m - 1, n + 1) *
integrate(cos(x)**(m - 2) * sin(x)**(n + 2), x))
else:
res = (Rational(-1, m + 1) * cos(x)**(m + 1) * sin(x)**(n - 1) +
Rational(n - 1, m + 1) *
integrate(cos(x)**(m + 2)*sin(x)**(n - 2), x))
if conds == 'piecewise':
return Piecewise((res.subs(x, a*x) / a, Ne(a, 0)), (zz, True))
return res.subs(x, a*x) / a
def _sin_pow_integrate(n, x):
if n > 0:
if n == 1:
#Recursion break
return -cos(x)
# n > 0
# / /
# | |
# | n -1 n-1 n - 1 | n-2
# | sin (x) dx = ______ cos (x) sin (x) + _______ | sin (x) dx
# | |
# | n n |
#/ /
#
#
return (Rational(-1, n) * cos(x) * sin(x)**(n - 1) +
Rational(n - 1, n) * _sin_pow_integrate(n - 2, x))
if n < 0:
if n == -1:
##Make sure this does not come back here again.
##Recursion breaks here or at n==0.
return trigintegrate(1/sin(x), x)
# n < 0
# / /
# | |
# | n 1 n+1 n + 2 | n+2
# | sin (x) dx = _______ cos (x) sin (x) + _______ | sin (x) dx
# | |
# | n + 1 n + 1 |
#/ /
#
return (Rational(1, n + 1) * cos(x) * sin(x)**(n + 1) +
Rational(n + 2, n + 1) * _sin_pow_integrate(n + 2, x))
else:
#n == 0
#Recursion break.
return x
def _cos_pow_integrate(n, x):
if n > 0:
if n == 1:
#Recursion break.
return sin(x)
# n > 0
# / /
# | |
# | n 1 n-1 n - 1 | n-2
# | sin (x) dx = ______ sin (x) cos (x) + _______ | cos (x) dx
# | |
# | n n |
#/ /
#
return (Rational(1, n) * sin(x) * cos(x)**(n - 1) +
Rational(n - 1, n) * _cos_pow_integrate(n - 2, x))
if n < 0:
if n == -1:
##Recursion break
return trigintegrate(1/cos(x), x)
# n < 0
# / /
# | |
# | n -1 n+1 n + 2 | n+2
# | cos (x) dx = _______ sin (x) cos (x) + _______ | cos (x) dx
# | |
# | n + 1 n + 1 |
#/ /
#
return (Rational(-1, n + 1) * sin(x) * cos(x)**(n + 1) +
Rational(n + 2, n + 1) * _cos_pow_integrate(n + 2, x))
else:
# n == 0
#Recursion Break.
return x
PK ]ZZZ & sympy/integrals/benchmarks/__init__.pyPK ]ZZZ�d�� � - sympy/integrals/benchmarks/bench_integrate.pyfrom sympy.core.symbol import Symbol
from sympy.functions.elementary.trigonometric import sin
from sympy.integrals.integrals import integrate
x = Symbol('x')
def bench_integrate_sin():
integrate(sin(x), x)
def bench_integrate_x1sin():
integrate(x**1*sin(x), x)
def bench_integrate_x2sin():
integrate(x**2*sin(x), x)
def bench_integrate_x3sin():
integrate(x**3*sin(x), x)
PK ]ZZZ��1�1 1 1 sympy/integrals/benchmarks/bench_trigintegrate.pyfrom sympy.core.symbol import Symbol
from sympy.functions.elementary.trigonometric import sin
from sympy.integrals.trigonometry import trigintegrate
x = Symbol('x')
def timeit_trigintegrate_sin3x():
trigintegrate(sin(x)**3, x)
def timeit_trigintegrate_x2():
trigintegrate(x**2, x) # -> None
PK ]ZZZ�+�N� � sympy/interactive/__init__.py"""Helper module for setting up interactive SymPy sessions. """
from .printing import init_printing
from .session import init_session
from .traversal import interactive_traversal
__all__ = ['init_printing', 'init_session', 'interactive_traversal']
PK ]ZZZظ�
�X �X sympy/interactive/printing.py"""Tools for setting up printing in interactive sessions. """
from sympy.external.importtools import version_tuple
from io import BytesIO
from sympy.printing.latex import latex as default_latex
from sympy.printing.preview import preview
from sympy.utilities.misc import debug
from sympy.printing.defaults import Printable
def _init_python_printing(stringify_func, **settings):
"""Setup printing in Python interactive session. """
import sys
import builtins
def _displayhook(arg):
"""Python's pretty-printer display hook.
This function was adapted from:
https://www.python.org/dev/peps/pep-0217/
"""
if arg is not None:
builtins._ = None
print(stringify_func(arg, **settings))
builtins._ = arg
sys.displayhook = _displayhook
def _init_ipython_printing(ip, stringify_func, use_latex, euler, forecolor,
backcolor, fontsize, latex_mode, print_builtin,
latex_printer, scale, **settings):
"""Setup printing in IPython interactive session. """
try:
from IPython.lib.latextools import latex_to_png
except ImportError:
pass
# Guess best font color if none was given based on the ip.colors string.
# From the IPython documentation:
# It has four case-insensitive values: 'nocolor', 'neutral', 'linux',
# 'lightbg'. The default is neutral, which should be legible on either
# dark or light terminal backgrounds. linux is optimised for dark
# backgrounds and lightbg for light ones.
if forecolor is None:
color = ip.colors.lower()
if color == 'lightbg':
forecolor = 'Black'
elif color == 'linux':
forecolor = 'White'
else:
# No idea, go with gray.
forecolor = 'Gray'
debug("init_printing: Automatic foreground color:", forecolor)
if use_latex == "svg":
extra_preamble = "\n\\special{color %s}" % forecolor
else:
extra_preamble = ""
imagesize = 'tight'
offset = "0cm,0cm"
resolution = round(150*scale)
dvi = r"-T %s -D %d -bg %s -fg %s -O %s" % (
imagesize, resolution, backcolor, forecolor, offset)
dvioptions = dvi.split()
svg_scale = 150/72*scale
dvioptions_svg = ["--no-fonts", "--scale={}".format(svg_scale)]
debug("init_printing: DVIOPTIONS:", dvioptions)
debug("init_printing: DVIOPTIONS_SVG:", dvioptions_svg)
latex = latex_printer or default_latex
def _print_plain(arg, p, cycle):
"""caller for pretty, for use in IPython 0.11"""
if _can_print(arg):
p.text(stringify_func(arg))
else:
p.text(IPython.lib.pretty.pretty(arg))
def _preview_wrapper(o):
exprbuffer = BytesIO()
try:
preview(o, output='png', viewer='BytesIO', euler=euler,
outputbuffer=exprbuffer, extra_preamble=extra_preamble,
dvioptions=dvioptions, fontsize=fontsize)
except Exception as e:
# IPython swallows exceptions
debug("png printing:", "_preview_wrapper exception raised:",
repr(e))
raise
return exprbuffer.getvalue()
def _svg_wrapper(o):
exprbuffer = BytesIO()
try:
preview(o, output='svg', viewer='BytesIO', euler=euler,
outputbuffer=exprbuffer, extra_preamble=extra_preamble,
dvioptions=dvioptions_svg, fontsize=fontsize)
except Exception as e:
# IPython swallows exceptions
debug("svg printing:", "_preview_wrapper exception raised:",
repr(e))
raise
return exprbuffer.getvalue().decode('utf-8')
def _matplotlib_wrapper(o):
# mathtext can't render some LaTeX commands. For example, it can't
# render any LaTeX environments such as array or matrix. So here we
# ensure that if mathtext fails to render, we return None.
try:
try:
return latex_to_png(o, color=forecolor, scale=scale)
except TypeError: # Old IPython version without color and scale
return latex_to_png(o)
except ValueError as e:
debug('matplotlib exception caught:', repr(e))
return None
# Hook methods for builtin SymPy printers
printing_hooks = ('_latex', '_sympystr', '_pretty', '_sympyrepr')
def _can_print(o):
"""Return True if type o can be printed with one of the SymPy printers.
If o is a container type, this is True if and only if every element of
o can be printed in this way.
"""
try:
# If you're adding another type, make sure you add it to printable_types
# later in this file as well
builtin_types = (list, tuple, set, frozenset)
if isinstance(o, builtin_types):
# If the object is a custom subclass with a custom str or
# repr, use that instead.
if (type(o).__str__ not in (i.__str__ for i in builtin_types) or
type(o).__repr__ not in (i.__repr__ for i in builtin_types)):
return False
return all(_can_print(i) for i in o)
elif isinstance(o, dict):
return all(_can_print(i) and _can_print(o[i]) for i in o)
elif isinstance(o, bool):
return False
elif isinstance(o, Printable):
# types known to SymPy
return True
elif any(hasattr(o, hook) for hook in printing_hooks):
# types which add support themselves
return True
elif isinstance(o, (float, int)) and print_builtin:
return True
return False
except RuntimeError:
return False
# This is in case maximum recursion depth is reached.
# Since RecursionError is for versions of Python 3.5+
# so this is to guard against RecursionError for older versions.
def _print_latex_png(o):
"""
A function that returns a png rendered by an external latex
distribution, falling back to matplotlib rendering
"""
if _can_print(o):
s = latex(o, mode=latex_mode, **settings)
if latex_mode == 'plain':
s = '$\\displaystyle %s$' % s
try:
return _preview_wrapper(s)
except RuntimeError as e:
debug('preview failed with:', repr(e),
' Falling back to matplotlib backend')
if latex_mode != 'inline':
s = latex(o, mode='inline', **settings)
return _matplotlib_wrapper(s)
def _print_latex_svg(o):
"""
A function that returns a svg rendered by an external latex
distribution, no fallback available.
"""
if _can_print(o):
s = latex(o, mode=latex_mode, **settings)
if latex_mode == 'plain':
s = '$\\displaystyle %s$' % s
try:
return _svg_wrapper(s)
except RuntimeError as e:
debug('preview failed with:', repr(e),
' No fallback available.')
def _print_latex_matplotlib(o):
"""
A function that returns a png rendered by mathtext
"""
if _can_print(o):
s = latex(o, mode='inline', **settings)
return _matplotlib_wrapper(s)
def _print_latex_text(o):
"""
A function to generate the latex representation of SymPy expressions.
"""
if _can_print(o):
s = latex(o, mode=latex_mode, **settings)
if latex_mode == 'plain':
return '$\\displaystyle %s$' % s
return s
def _result_display(self, arg):
"""IPython's pretty-printer display hook, for use in IPython 0.10
This function was adapted from:
ipython/IPython/hooks.py:155
"""
if self.rc.pprint:
out = stringify_func(arg)
if '\n' in out:
print()
print(out)
else:
print(repr(arg))
import IPython
if version_tuple(IPython.__version__) >= version_tuple('0.11'):
# Printable is our own type, so we handle it with methods instead of
# the approach required by builtin types. This allows downstream
# packages to override the methods in their own subclasses of Printable,
# which avoids the effects of gh-16002.
printable_types = [float, tuple, list, set, frozenset, dict, int]
plaintext_formatter = ip.display_formatter.formatters['text/plain']
# Exception to the rule above: IPython has better dispatching rules
# for plaintext printing (xref ipython/ipython#8938), and we can't
# use `_repr_pretty_` without hitting a recursion error in _print_plain.
for cls in printable_types + [Printable]:
plaintext_formatter.for_type(cls, _print_plain)
svg_formatter = ip.display_formatter.formatters['image/svg+xml']
if use_latex in ('svg', ):
debug("init_printing: using svg formatter")
for cls in printable_types:
svg_formatter.for_type(cls, _print_latex_svg)
Printable._repr_svg_ = _print_latex_svg
else:
debug("init_printing: not using any svg formatter")
for cls in printable_types:
# Better way to set this, but currently does not work in IPython
#png_formatter.for_type(cls, None)
if cls in svg_formatter.type_printers:
svg_formatter.type_printers.pop(cls)
Printable._repr_svg_ = Printable._repr_disabled
png_formatter = ip.display_formatter.formatters['image/png']
if use_latex in (True, 'png'):
debug("init_printing: using png formatter")
for cls in printable_types:
png_formatter.for_type(cls, _print_latex_png)
Printable._repr_png_ = _print_latex_png
elif use_latex == 'matplotlib':
debug("init_printing: using matplotlib formatter")
for cls in printable_types:
png_formatter.for_type(cls, _print_latex_matplotlib)
Printable._repr_png_ = _print_latex_matplotlib
else:
debug("init_printing: not using any png formatter")
for cls in printable_types:
# Better way to set this, but currently does not work in IPython
#png_formatter.for_type(cls, None)
if cls in png_formatter.type_printers:
png_formatter.type_printers.pop(cls)
Printable._repr_png_ = Printable._repr_disabled
latex_formatter = ip.display_formatter.formatters['text/latex']
if use_latex in (True, 'mathjax'):
debug("init_printing: using mathjax formatter")
for cls in printable_types:
latex_formatter.for_type(cls, _print_latex_text)
Printable._repr_latex_ = _print_latex_text
else:
debug("init_printing: not using text/latex formatter")
for cls in printable_types:
# Better way to set this, but currently does not work in IPython
#latex_formatter.for_type(cls, None)
if cls in latex_formatter.type_printers:
latex_formatter.type_printers.pop(cls)
Printable._repr_latex_ = Printable._repr_disabled
else:
ip.set_hook('result_display', _result_display)
def _is_ipython(shell):
"""Is a shell instance an IPython shell?"""
# shortcut, so we don't import IPython if we don't have to
from sys import modules
if 'IPython' not in modules:
return False
try:
from IPython.core.interactiveshell import InteractiveShell
except ImportError:
# IPython < 0.11
try:
from IPython.iplib import InteractiveShell
except ImportError:
# Reaching this points means IPython has changed in a backward-incompatible way
# that we don't know about. Warn?
return False
return isinstance(shell, InteractiveShell)
# Used by the doctester to override the default for no_global
NO_GLOBAL = False
def init_printing(pretty_print=True, order=None, use_unicode=None,
use_latex=None, wrap_line=None, num_columns=None,
no_global=False, ip=None, euler=False, forecolor=None,
backcolor='Transparent', fontsize='10pt',
latex_mode='plain', print_builtin=True,
str_printer=None, pretty_printer=None,
latex_printer=None, scale=1.0, **settings):
r"""
Initializes pretty-printer depending on the environment.
Parameters
==========
pretty_print : bool, default=True
If ``True``, use :func:`~.pretty_print` to stringify or the provided pretty
printer; if ``False``, use :func:`~.sstrrepr` to stringify or the provided string
printer.
order : string or None, default='lex'
There are a few different settings for this parameter:
``'lex'`` (default), which is lexographic order;
``'grlex'``, which is graded lexographic order;
``'grevlex'``, which is reversed graded lexographic order;
``'old'``, which is used for compatibility reasons and for long expressions;
``None``, which sets it to lex.
use_unicode : bool or None, default=None
If ``True``, use unicode characters;
if ``False``, do not use unicode characters;
if ``None``, make a guess based on the environment.
use_latex : string, bool, or None, default=None
If ``True``, use default LaTeX rendering in GUI interfaces (png and
mathjax);
if ``False``, do not use LaTeX rendering;
if ``None``, make a guess based on the environment;
if ``'png'``, enable LaTeX rendering with an external LaTeX compiler,
falling back to matplotlib if external compilation fails;
if ``'matplotlib'``, enable LaTeX rendering with matplotlib;
if ``'mathjax'``, enable LaTeX text generation, for example MathJax
rendering in IPython notebook or text rendering in LaTeX documents;
if ``'svg'``, enable LaTeX rendering with an external latex compiler,
no fallback
wrap_line : bool
If True, lines will wrap at the end; if False, they will not wrap
but continue as one line. This is only relevant if ``pretty_print`` is
True.
num_columns : int or None, default=None
If ``int``, number of columns before wrapping is set to num_columns; if
``None``, number of columns before wrapping is set to terminal width.
This is only relevant if ``pretty_print`` is ``True``.
no_global : bool, default=False
If ``True``, the settings become system wide;
if ``False``, use just for this console/session.
ip : An interactive console
This can either be an instance of IPython,
or a class that derives from code.InteractiveConsole.
euler : bool, optional, default=False
Loads the euler package in the LaTeX preamble for handwritten style
fonts (https://www.ctan.org/pkg/euler).
forecolor : string or None, optional, default=None
DVI setting for foreground color. ``None`` means that either ``'Black'``,
``'White'``, or ``'Gray'`` will be selected based on a guess of the IPython
terminal color setting. See notes.
backcolor : string, optional, default='Transparent'
DVI setting for background color. See notes.
fontsize : string or int, optional, default='10pt'
A font size to pass to the LaTeX documentclass function in the
preamble. Note that the options are limited by the documentclass.
Consider using scale instead.
latex_mode : string, optional, default='plain'
The mode used in the LaTeX printer. Can be one of:
``{'inline'|'plain'|'equation'|'equation*'}``.
print_builtin : boolean, optional, default=True
If ``True`` then floats and integers will be printed. If ``False`` the
printer will only print SymPy types.
str_printer : function, optional, default=None
A custom string printer function. This should mimic
:func:`~.sstrrepr`.
pretty_printer : function, optional, default=None
A custom pretty printer. This should mimic :func:`~.pretty`.
latex_printer : function, optional, default=None
A custom LaTeX printer. This should mimic :func:`~.latex`.
scale : float, optional, default=1.0
Scale the LaTeX output when using the ``'png'`` or ``'svg'`` backends.
Useful for high dpi screens.
settings :
Any additional settings for the ``latex`` and ``pretty`` commands can
be used to fine-tune the output.
Examples
========
>>> from sympy.interactive import init_printing
>>> from sympy import Symbol, sqrt
>>> from sympy.abc import x, y
>>> sqrt(5)
sqrt(5)
>>> init_printing(pretty_print=True) # doctest: +SKIP
>>> sqrt(5) # doctest: +SKIP
___
\/ 5
>>> theta = Symbol('theta') # doctest: +SKIP
>>> init_printing(use_unicode=True) # doctest: +SKIP
>>> theta # doctest: +SKIP
\u03b8
>>> init_printing(use_unicode=False) # doctest: +SKIP
>>> theta # doctest: +SKIP
theta
>>> init_printing(order='lex') # doctest: +SKIP
>>> str(y + x + y**2 + x**2) # doctest: +SKIP
x**2 + x + y**2 + y
>>> init_printing(order='grlex') # doctest: +SKIP
>>> str(y + x + y**2 + x**2) # doctest: +SKIP
x**2 + x + y**2 + y
>>> init_printing(order='grevlex') # doctest: +SKIP
>>> str(y * x**2 + x * y**2) # doctest: +SKIP
x**2*y + x*y**2
>>> init_printing(order='old') # doctest: +SKIP
>>> str(x**2 + y**2 + x + y) # doctest: +SKIP
x**2 + x + y**2 + y
>>> init_printing(num_columns=10) # doctest: +SKIP
>>> x**2 + x + y**2 + y # doctest: +SKIP
x + y +
x**2 + y**2
Notes
=====
The foreground and background colors can be selected when using ``'png'`` or
``'svg'`` LaTeX rendering. Note that before the ``init_printing`` command is
executed, the LaTeX rendering is handled by the IPython console and not SymPy.
The colors can be selected among the 68 standard colors known to ``dvips``,
for a list see [1]_. In addition, the background color can be
set to ``'Transparent'`` (which is the default value).
When using the ``'Auto'`` foreground color, the guess is based on the
``colors`` variable in the IPython console, see [2]_. Hence, if
that variable is set correctly in your IPython console, there is a high
chance that the output will be readable, although manual settings may be
needed.
References
==========
.. [1] https://en.wikibooks.org/wiki/LaTeX/Colors#The_68_standard_colors_known_to_dvips
.. [2] https://ipython.readthedocs.io/en/stable/config/details.html#terminal-colors
See Also
========
sympy.printing.latex
sympy.printing.pretty
"""
import sys
from sympy.printing.printer import Printer
if pretty_print:
if pretty_printer is not None:
stringify_func = pretty_printer
else:
from sympy.printing import pretty as stringify_func
else:
if str_printer is not None:
stringify_func = str_printer
else:
from sympy.printing import sstrrepr as stringify_func
# Even if ip is not passed, double check that not in IPython shell
in_ipython = False
if ip is None:
try:
ip = get_ipython()
except NameError:
pass
else:
in_ipython = (ip is not None)
if ip and not in_ipython:
in_ipython = _is_ipython(ip)
if in_ipython and pretty_print:
try:
import IPython
# IPython 1.0 deprecates the frontend module, so we import directly
# from the terminal module to prevent a deprecation message from being
# shown.
if version_tuple(IPython.__version__) >= version_tuple('1.0'):
from IPython.terminal.interactiveshell import TerminalInteractiveShell
else:
from IPython.frontend.terminal.interactiveshell import TerminalInteractiveShell
from code import InteractiveConsole
except ImportError:
pass
else:
# This will be True if we are in the qtconsole or notebook
if not isinstance(ip, (InteractiveConsole, TerminalInteractiveShell)) \
and 'ipython-console' not in ''.join(sys.argv):
if use_unicode is None:
debug("init_printing: Setting use_unicode to True")
use_unicode = True
if use_latex is None:
debug("init_printing: Setting use_latex to True")
use_latex = True
if not NO_GLOBAL and not no_global:
Printer.set_global_settings(order=order, use_unicode=use_unicode,
wrap_line=wrap_line, num_columns=num_columns)
else:
_stringify_func = stringify_func
if pretty_print:
stringify_func = lambda expr, **settings: \
_stringify_func(expr, order=order,
use_unicode=use_unicode,
wrap_line=wrap_line,
num_columns=num_columns,
**settings)
else:
stringify_func = \
lambda expr, **settings: _stringify_func(
expr, order=order, **settings)
if in_ipython:
mode_in_settings = settings.pop("mode", None)
if mode_in_settings:
debug("init_printing: Mode is not able to be set due to internals"
"of IPython printing")
_init_ipython_printing(ip, stringify_func, use_latex, euler,
forecolor, backcolor, fontsize, latex_mode,
print_builtin, latex_printer, scale,
**settings)
else:
_init_python_printing(stringify_func, **settings)
PK ]ZZZ&���; �; sympy/interactive/session.py"""Tools for setting up interactive sessions. """
from sympy.external.gmpy import GROUND_TYPES
from sympy.external.importtools import version_tuple
from sympy.interactive.printing import init_printing
from sympy.utilities.misc import ARCH
preexec_source = """\
from sympy import *
x, y, z, t = symbols('x y z t')
k, m, n = symbols('k m n', integer=True)
f, g, h = symbols('f g h', cls=Function)
init_printing()
"""
verbose_message = """\
These commands were executed:
%(source)s
Documentation can be found at https://docs.sympy.org/%(version)s
"""
no_ipython = """\
Could not locate IPython. Having IPython installed is greatly recommended.
See http://ipython.scipy.org for more details. If you use Debian/Ubuntu,
just install the 'ipython' package and start isympy again.
"""
def _make_message(ipython=True, quiet=False, source=None):
"""Create a banner for an interactive session. """
from sympy import __version__ as sympy_version
from sympy import SYMPY_DEBUG
import sys
import os
if quiet:
return ""
python_version = "%d.%d.%d" % sys.version_info[:3]
if ipython:
shell_name = "IPython"
else:
shell_name = "Python"
info = ['ground types: %s' % GROUND_TYPES]
cache = os.getenv('SYMPY_USE_CACHE')
if cache is not None and cache.lower() == 'no':
info.append('cache: off')
if SYMPY_DEBUG:
info.append('debugging: on')
args = shell_name, sympy_version, python_version, ARCH, ', '.join(info)
message = "%s console for SymPy %s (Python %s-%s) (%s)\n" % args
if source is None:
source = preexec_source
_source = ""
for line in source.split('\n')[:-1]:
if not line:
_source += '\n'
else:
_source += '>>> ' + line + '\n'
doc_version = sympy_version
if 'dev' in doc_version:
doc_version = "dev"
else:
doc_version = "%s/" % doc_version
message += '\n' + verbose_message % {'source': _source,
'version': doc_version}
return message
def int_to_Integer(s):
"""
Wrap integer literals with Integer.
This is based on the decistmt example from
https://docs.python.org/3/library/tokenize.html.
Only integer literals are converted. Float literals are left alone.
Examples
========
>>> from sympy import Integer # noqa: F401
>>> from sympy.interactive.session import int_to_Integer
>>> s = '1.2 + 1/2 - 0x12 + a1'
>>> int_to_Integer(s)
'1.2 +Integer (1 )/Integer (2 )-Integer (0x12 )+a1 '
>>> s = 'print (1/2)'
>>> int_to_Integer(s)
'print (Integer (1 )/Integer (2 ))'
>>> exec(s)
0.5
>>> exec(int_to_Integer(s))
1/2
"""
from tokenize import generate_tokens, untokenize, NUMBER, NAME, OP
from io import StringIO
def _is_int(num):
"""
Returns true if string value num (with token NUMBER) represents an integer.
"""
# XXX: Is there something in the standard library that will do this?
if '.' in num or 'j' in num.lower() or 'e' in num.lower():
return False
return True
result = []
g = generate_tokens(StringIO(s).readline) # tokenize the string
for toknum, tokval, _, _, _ in g:
if toknum == NUMBER and _is_int(tokval): # replace NUMBER tokens
result.extend([
(NAME, 'Integer'),
(OP, '('),
(NUMBER, tokval),
(OP, ')')
])
else:
result.append((toknum, tokval))
return untokenize(result)
def enable_automatic_int_sympification(shell):
"""
Allow IPython to automatically convert integer literals to Integer.
"""
import ast
old_run_cell = shell.run_cell
def my_run_cell(cell, *args, **kwargs):
try:
# Check the cell for syntax errors. This way, the syntax error
# will show the original input, not the transformed input. The
# downside here is that IPython magic like %timeit will not work
# with transformed input (but on the other hand, IPython magic
# that doesn't expect transformed input will continue to work).
ast.parse(cell)
except SyntaxError:
pass
else:
cell = int_to_Integer(cell)
return old_run_cell(cell, *args, **kwargs)
shell.run_cell = my_run_cell
def enable_automatic_symbols(shell):
"""Allow IPython to automatically create symbols (``isympy -a``). """
# XXX: This should perhaps use tokenize, like int_to_Integer() above.
# This would avoid re-executing the code, which can lead to subtle
# issues. For example:
#
# In [1]: a = 1
#
# In [2]: for i in range(10):
# ...: a += 1
# ...:
#
# In [3]: a
# Out[3]: 11
#
# In [4]: a = 1
#
# In [5]: for i in range(10):
# ...: a += 1
# ...: print b
# ...:
# b
# b
# b
# b
# b
# b
# b
# b
# b
# b
#
# In [6]: a
# Out[6]: 12
#
# Note how the for loop is executed again because `b` was not defined, but `a`
# was already incremented once, so the result is that it is incremented
# multiple times.
import re
re_nameerror = re.compile(
"name '(?P<symbol>[A-Za-z_][A-Za-z0-9_]*)' is not defined")
def _handler(self, etype, value, tb, tb_offset=None):
"""Handle :exc:`NameError` exception and allow injection of missing symbols. """
if etype is NameError and tb.tb_next and not tb.tb_next.tb_next:
match = re_nameerror.match(str(value))
if match is not None:
# XXX: Make sure Symbol is in scope. Otherwise you'll get infinite recursion.
self.run_cell("%(symbol)s = Symbol('%(symbol)s')" %
{'symbol': match.group("symbol")}, store_history=False)
try:
code = self.user_ns['In'][-1]
except (KeyError, IndexError):
pass
else:
self.run_cell(code, store_history=False)
return None
finally:
self.run_cell("del %s" % match.group("symbol"),
store_history=False)
stb = self.InteractiveTB.structured_traceback(
etype, value, tb, tb_offset=tb_offset)
self._showtraceback(etype, value, stb)
shell.set_custom_exc((NameError,), _handler)
def init_ipython_session(shell=None, argv=[], auto_symbols=False, auto_int_to_Integer=False):
"""Construct new IPython session. """
import IPython
if version_tuple(IPython.__version__) >= version_tuple('0.11'):
if not shell:
# use an app to parse the command line, and init config
# IPython 1.0 deprecates the frontend module, so we import directly
# from the terminal module to prevent a deprecation message from being
# shown.
if version_tuple(IPython.__version__) >= version_tuple('1.0'):
from IPython.terminal import ipapp
else:
from IPython.frontend.terminal import ipapp
app = ipapp.TerminalIPythonApp()
# don't draw IPython banner during initialization:
app.display_banner = False
app.initialize(argv)
shell = app.shell
if auto_symbols:
enable_automatic_symbols(shell)
if auto_int_to_Integer:
enable_automatic_int_sympification(shell)
return shell
else:
from IPython.Shell import make_IPython
return make_IPython(argv)
def init_python_session():
"""Construct new Python session. """
from code import InteractiveConsole
class SymPyConsole(InteractiveConsole):
"""An interactive console with readline support. """
def __init__(self):
ns_locals = {}
InteractiveConsole.__init__(self, locals=ns_locals)
try:
import rlcompleter
import readline
except ImportError:
pass
else:
import os
import atexit
readline.set_completer(rlcompleter.Completer(ns_locals).complete)
readline.parse_and_bind('tab: complete')
if hasattr(readline, 'read_history_file'):
history = os.path.expanduser('~/.sympy-history')
try:
readline.read_history_file(history)
except OSError:
pass
atexit.register(readline.write_history_file, history)
return SymPyConsole()
def init_session(ipython=None, pretty_print=True, order=None,
use_unicode=None, use_latex=None, quiet=False, auto_symbols=False,
auto_int_to_Integer=False, str_printer=None, pretty_printer=None,
latex_printer=None, argv=[]):
"""
Initialize an embedded IPython or Python session. The IPython session is
initiated with the --pylab option, without the numpy imports, so that
matplotlib plotting can be interactive.
Parameters
==========
pretty_print: boolean
If True, use pretty_print to stringify;
if False, use sstrrepr to stringify.
order: string or None
There are a few different settings for this parameter:
lex (default), which is lexographic order;
grlex, which is graded lexographic order;
grevlex, which is reversed graded lexographic order;
old, which is used for compatibility reasons and for long expressions;
None, which sets it to lex.
use_unicode: boolean or None
If True, use unicode characters;
if False, do not use unicode characters.
use_latex: boolean or None
If True, use latex rendering if IPython GUI's;
if False, do not use latex rendering.
quiet: boolean
If True, init_session will not print messages regarding its status;
if False, init_session will print messages regarding its status.
auto_symbols: boolean
If True, IPython will automatically create symbols for you.
If False, it will not.
The default is False.
auto_int_to_Integer: boolean
If True, IPython will automatically wrap int literals with Integer, so
that things like 1/2 give Rational(1, 2).
If False, it will not.
The default is False.
ipython: boolean or None
If True, printing will initialize for an IPython console;
if False, printing will initialize for a normal console;
The default is None, which automatically determines whether we are in
an ipython instance or not.
str_printer: function, optional, default=None
A custom string printer function. This should mimic
sympy.printing.sstrrepr().
pretty_printer: function, optional, default=None
A custom pretty printer. This should mimic sympy.printing.pretty().
latex_printer: function, optional, default=None
A custom LaTeX printer. This should mimic sympy.printing.latex()
This should mimic sympy.printing.latex().
argv: list of arguments for IPython
See sympy.bin.isympy for options that can be used to initialize IPython.
See Also
========
sympy.interactive.printing.init_printing: for examples and the rest of the parameters.
Examples
========
>>> from sympy import init_session, Symbol, sin, sqrt
>>> sin(x) #doctest: +SKIP
NameError: name 'x' is not defined
>>> init_session() #doctest: +SKIP
>>> sin(x) #doctest: +SKIP
sin(x)
>>> sqrt(5) #doctest: +SKIP
___
\\/ 5
>>> init_session(pretty_print=False) #doctest: +SKIP
>>> sqrt(5) #doctest: +SKIP
sqrt(5)
>>> y + x + y**2 + x**2 #doctest: +SKIP
x**2 + x + y**2 + y
>>> init_session(order='grlex') #doctest: +SKIP
>>> y + x + y**2 + x**2 #doctest: +SKIP
x**2 + y**2 + x + y
>>> init_session(order='grevlex') #doctest: +SKIP
>>> y * x**2 + x * y**2 #doctest: +SKIP
x**2*y + x*y**2
>>> init_session(order='old') #doctest: +SKIP
>>> x**2 + y**2 + x + y #doctest: +SKIP
x + y + x**2 + y**2
>>> theta = Symbol('theta') #doctest: +SKIP
>>> theta #doctest: +SKIP
theta
>>> init_session(use_unicode=True) #doctest: +SKIP
>>> theta # doctest: +SKIP
\u03b8
"""
import sys
in_ipython = False
if ipython is not False:
try:
import IPython
except ImportError:
if ipython is True:
raise RuntimeError("IPython is not available on this system")
ip = None
else:
try:
from IPython import get_ipython
ip = get_ipython()
except ImportError:
ip = None
in_ipython = bool(ip)
if ipython is None:
ipython = in_ipython
if ipython is False:
ip = init_python_session()
mainloop = ip.interact
else:
ip = init_ipython_session(ip, argv=argv, auto_symbols=auto_symbols,
auto_int_to_Integer=auto_int_to_Integer)
if version_tuple(IPython.__version__) >= version_tuple('0.11'):
# runsource is gone, use run_cell instead, which doesn't
# take a symbol arg. The second arg is `store_history`,
# and False means don't add the line to IPython's history.
ip.runsource = lambda src, symbol='exec': ip.run_cell(src, False)
# Enable interactive plotting using pylab.
try:
ip.enable_pylab(import_all=False)
except Exception:
# Causes an import error if matplotlib is not installed.
# Causes other errors (depending on the backend) if there
# is no display, or if there is some problem in the
# backend, so we have a bare "except Exception" here
pass
if not in_ipython:
mainloop = ip.mainloop
if auto_symbols and (not ipython or version_tuple(IPython.__version__) < version_tuple('0.11')):
raise RuntimeError("automatic construction of symbols is possible only in IPython 0.11 or above")
if auto_int_to_Integer and (not ipython or version_tuple(IPython.__version__) < version_tuple('0.11')):
raise RuntimeError("automatic int to Integer transformation is possible only in IPython 0.11 or above")
_preexec_source = preexec_source
ip.runsource(_preexec_source, symbol='exec')
init_printing(pretty_print=pretty_print, order=order,
use_unicode=use_unicode, use_latex=use_latex, ip=ip,
str_printer=str_printer, pretty_printer=pretty_printer,
latex_printer=latex_printer)
message = _make_message(ipython, quiet, _preexec_source)
if not in_ipython:
print(message)
mainloop()
sys.exit('Exiting ...')
else:
print(message)
import atexit
atexit.register(lambda: print("Exiting ...\n"))
PK ]ZZZA���u u sympy/interactive/traversal.pyfrom sympy.core.basic import Basic
from sympy.printing import pprint
import random
def interactive_traversal(expr):
"""Traverse a tree asking a user which branch to choose. """
RED, BRED = '\033[0;31m', '\033[1;31m'
GREEN, BGREEN = '\033[0;32m', '\033[1;32m'
YELLOW, BYELLOW = '\033[0;33m', '\033[1;33m' # noqa
BLUE, BBLUE = '\033[0;34m', '\033[1;34m' # noqa
MAGENTA, BMAGENTA = '\033[0;35m', '\033[1;35m'# noqa
CYAN, BCYAN = '\033[0;36m', '\033[1;36m' # noqa
END = '\033[0m'
def cprint(*args):
print("".join(map(str, args)) + END)
def _interactive_traversal(expr, stage):
if stage > 0:
print()
cprint("Current expression (stage ", BYELLOW, stage, END, "):")
print(BCYAN)
pprint(expr)
print(END)
if isinstance(expr, Basic):
if expr.is_Add:
args = expr.as_ordered_terms()
elif expr.is_Mul:
args = expr.as_ordered_factors()
else:
args = expr.args
elif hasattr(expr, "__iter__"):
args = list(expr)
else:
return expr
n_args = len(args)
if not n_args:
return expr
for i, arg in enumerate(args):
cprint(GREEN, "[", BGREEN, i, GREEN, "] ", BLUE, type(arg), END)
pprint(arg)
print()
if n_args == 1:
choices = '0'
else:
choices = '0-%d' % (n_args - 1)
try:
choice = input("Your choice [%s,f,l,r,d,?]: " % choices)
except EOFError:
result = expr
print()
else:
if choice == '?':
cprint(RED, "%s - select subexpression with the given index" %
choices)
cprint(RED, "f - select the first subexpression")
cprint(RED, "l - select the last subexpression")
cprint(RED, "r - select a random subexpression")
cprint(RED, "d - done\n")
result = _interactive_traversal(expr, stage)
elif choice in ('d', ''):
result = expr
elif choice == 'f':
result = _interactive_traversal(args[0], stage + 1)
elif choice == 'l':
result = _interactive_traversal(args[-1], stage + 1)
elif choice == 'r':
result = _interactive_traversal(random.choice(args), stage + 1)
else:
try:
choice = int(choice)
except ValueError:
cprint(BRED,
"Choice must be a number in %s range\n" % choices)
result = _interactive_traversal(expr, stage)
else:
if choice < 0 or choice >= n_args:
cprint(BRED, "Choice must be in %s range\n" % choices)
result = _interactive_traversal(expr, stage)
else:
result = _interactive_traversal(args[choice], stage + 1)
return result
return _interactive_traversal(expr, 0)
PK ]ZZZ�0��O O sympy/liealgebras/__init__.pyfrom sympy.liealgebras.cartan_type import CartanType
__all__ = ['CartanType']
PK ]ZZZI�� " sympy/liealgebras/cartan_matrix.pyfrom .cartan_type import CartanType
def CartanMatrix(ct):
"""Access the Cartan matrix of a specific Lie algebra
Examples
========
>>> from sympy.liealgebras.cartan_matrix import CartanMatrix
>>> CartanMatrix("A2")
Matrix([
[ 2, -1],
[-1, 2]])
>>> CartanMatrix(['C', 3])
Matrix([
[ 2, -1, 0],
[-1, 2, -1],
[ 0, -2, 2]])
This method works by returning the Cartan matrix
which corresponds to Cartan type t.
"""
return CartanType(ct).cartan_matrix()
PK ]ZZZ����� � sympy/liealgebras/cartan_type.pyfrom sympy.core import Atom, Basic
class CartanType_generator():
"""
Constructor for actually creating things
"""
def __call__(self, *args):
c = args[0]
if isinstance(c, list):
letter, n = c[0], int(c[1])
elif isinstance(c, str):
letter, n = c[0], int(c[1:])
else:
raise TypeError("Argument must be a string (e.g. 'A3') or a list (e.g. ['A', 3])")
if n < 0:
raise ValueError("Lie algebra rank cannot be negative")
if letter == "A":
from . import type_a
return type_a.TypeA(n)
if letter == "B":
from . import type_b
return type_b.TypeB(n)
if letter == "C":
from . import type_c
return type_c.TypeC(n)
if letter == "D":
from . import type_d
return type_d.TypeD(n)
if letter == "E":
if n >= 6 and n <= 8:
from . import type_e
return type_e.TypeE(n)
if letter == "F":
if n == 4:
from . import type_f
return type_f.TypeF(n)
if letter == "G":
if n == 2:
from . import type_g
return type_g.TypeG(n)
CartanType = CartanType_generator()
class Standard_Cartan(Atom):
"""
Concrete base class for Cartan types such as A4, etc
"""
def __new__(cls, series, n):
obj = Basic.__new__(cls)
obj.n = n
obj.series = series
return obj
def rank(self):
"""
Returns the rank of the Lie algebra
"""
return self.n
def series(self):
"""
Returns the type of the Lie algebra
"""
return self.series
PK ]ZZZqi� # sympy/liealgebras/dynkin_diagram.pyfrom .cartan_type import CartanType
def DynkinDiagram(t):
"""Display the Dynkin diagram of a given Lie algebra
Works by generating the CartanType for the input, t, and then returning the
Dynkin diagram method from the individual classes.
Examples
========
>>> from sympy.liealgebras.dynkin_diagram import DynkinDiagram
>>> print(DynkinDiagram("A3"))
0---0---0
1 2 3
>>> print(DynkinDiagram("B4"))
0---0---0=>=0
1 2 3 4
"""
return CartanType(t).dynkin_diagram()
PK ]ZZZ=8G G sympy/liealgebras/root_system.pyfrom .cartan_type import CartanType
from sympy.core.basic import Atom
class RootSystem(Atom):
"""Represent the root system of a simple Lie algebra
Every simple Lie algebra has a unique root system. To find the root
system, we first consider the Cartan subalgebra of g, which is the maximal
abelian subalgebra, and consider the adjoint action of g on this
subalgebra. There is a root system associated with this action. Now, a
root system over a vector space V is a set of finite vectors Phi (called
roots), which satisfy:
1. The roots span V
2. The only scalar multiples of x in Phi are x and -x
3. For every x in Phi, the set Phi is closed under reflection
through the hyperplane perpendicular to x.
4. If x and y are roots in Phi, then the projection of y onto
the line through x is a half-integral multiple of x.
Now, there is a subset of Phi, which we will call Delta, such that:
1. Delta is a basis of V
2. Each root x in Phi can be written x = sum k_y y for y in Delta
The elements of Delta are called the simple roots.
Therefore, we see that the simple roots span the root space of a given
simple Lie algebra.
References
==========
.. [1] https://en.wikipedia.org/wiki/Root_system
.. [2] Lie Algebras and Representation Theory - Humphreys
"""
def __new__(cls, cartantype):
"""Create a new RootSystem object
This method assigns an attribute called cartan_type to each instance of
a RootSystem object. When an instance of RootSystem is called, it
needs an argument, which should be an instance of a simple Lie algebra.
We then take the CartanType of this argument and set it as the
cartan_type attribute of the RootSystem instance.
"""
obj = Atom.__new__(cls)
obj.cartan_type = CartanType(cartantype)
return obj
def simple_roots(self):
"""Generate the simple roots of the Lie algebra
The rank of the Lie algebra determines the number of simple roots that
it has. This method obtains the rank of the Lie algebra, and then uses
the simple_root method from the Lie algebra classes to generate all the
simple roots.
Examples
========
>>> from sympy.liealgebras.root_system import RootSystem
>>> c = RootSystem("A3")
>>> roots = c.simple_roots()
>>> roots
{1: [1, -1, 0, 0], 2: [0, 1, -1, 0], 3: [0, 0, 1, -1]}
"""
n = self.cartan_type.rank()
roots = {}
for i in range(1, n+1):
root = self.cartan_type.simple_root(i)
roots[i] = root
return roots
def all_roots(self):
"""Generate all the roots of a given root system
The result is a dictionary where the keys are integer numbers. It
generates the roots by getting the dictionary of all positive roots
from the bases classes, and then taking each root, and multiplying it
by -1 and adding it to the dictionary. In this way all the negative
roots are generated.
"""
alpha = self.cartan_type.positive_roots()
keys = list(alpha.keys())
k = max(keys)
for val in keys:
k += 1
root = alpha[val]
newroot = [-x for x in root]
alpha[k] = newroot
return alpha
def root_space(self):
"""Return the span of the simple roots
The root space is the vector space spanned by the simple roots, i.e. it
is a vector space with a distinguished basis, the simple roots. This
method returns a string that represents the root space as the span of
the simple roots, alpha[1],...., alpha[n].
Examples
========
>>> from sympy.liealgebras.root_system import RootSystem
>>> c = RootSystem("A3")
>>> c.root_space()
'alpha[1] + alpha[2] + alpha[3]'
"""
n = self.cartan_type.rank()
rs = " + ".join("alpha["+str(i) +"]" for i in range(1, n+1))
return rs
def add_simple_roots(self, root1, root2):
"""Add two simple roots together
The function takes as input two integers, root1 and root2. It then
uses these integers as keys in the dictionary of simple roots, and gets
the corresponding simple roots, and then adds them together.
Examples
========
>>> from sympy.liealgebras.root_system import RootSystem
>>> c = RootSystem("A3")
>>> newroot = c.add_simple_roots(1, 2)
>>> newroot
[1, 0, -1, 0]
"""
alpha = self.simple_roots()
if root1 > len(alpha) or root2 > len(alpha):
raise ValueError("You've used a root that doesn't exist!")
a1 = alpha[root1]
a2 = alpha[root2]
newroot = [_a1 + _a2 for _a1, _a2 in zip(a1, a2)]
return newroot
def add_as_roots(self, root1, root2):
"""Add two roots together if and only if their sum is also a root
It takes as input two vectors which should be roots. It then computes
their sum and checks if it is in the list of all possible roots. If it
is, it returns the sum. Otherwise it returns a string saying that the
sum is not a root.
Examples
========
>>> from sympy.liealgebras.root_system import RootSystem
>>> c = RootSystem("A3")
>>> c.add_as_roots([1, 0, -1, 0], [0, 0, 1, -1])
[1, 0, 0, -1]
>>> c.add_as_roots([1, -1, 0, 0], [0, 0, -1, 1])
'The sum of these two roots is not a root'
"""
alpha = self.all_roots()
newroot = [r1 + r2 for r1, r2 in zip(root1, root2)]
if newroot in alpha.values():
return newroot
else:
return "The sum of these two roots is not a root"
def cartan_matrix(self):
"""Cartan matrix of Lie algebra associated with this root system
Examples
========
>>> from sympy.liealgebras.root_system import RootSystem
>>> c = RootSystem("A3")
>>> c.cartan_matrix()
Matrix([
[ 2, -1, 0],
[-1, 2, -1],
[ 0, -1, 2]])
"""
return self.cartan_type.cartan_matrix()
def dynkin_diagram(self):
"""Dynkin diagram of the Lie algebra associated with this root system
Examples
========
>>> from sympy.liealgebras.root_system import RootSystem
>>> c = RootSystem("A3")
>>> print(c.dynkin_diagram())
0---0---0
1 2 3
"""
return self.cartan_type.dynkin_diagram()
PK ]ZZZ�:8�� � sympy/liealgebras/type_a.pyfrom sympy.liealgebras.cartan_type import Standard_Cartan
from sympy.core.backend import eye
class TypeA(Standard_Cartan):
"""
This class contains the information about
the A series of simple Lie algebras.
====
"""
def __new__(cls, n):
if n < 1:
raise ValueError("n cannot be less than 1")
return Standard_Cartan.__new__(cls, "A", n)
def dimension(self):
"""Dimension of the vector space V underlying the Lie algebra
Examples
========
>>> from sympy.liealgebras.cartan_type import CartanType
>>> c = CartanType("A4")
>>> c.dimension()
5
"""
return self.n+1
def basic_root(self, i, j):
"""
This is a method just to generate roots
with a 1 iin the ith position and a -1
in the jth position.
"""
n = self.n
root = [0]*(n+1)
root[i] = 1
root[j] = -1
return root
def simple_root(self, i):
"""
Every lie algebra has a unique root system.
Given a root system Q, there is a subset of the
roots such that an element of Q is called a
simple root if it cannot be written as the sum
of two elements in Q. If we let D denote the
set of simple roots, then it is clear that every
element of Q can be written as a linear combination
of elements of D with all coefficients non-negative.
In A_n the ith simple root is the root which has a 1
in the ith position, a -1 in the (i+1)th position,
and zeroes elsewhere.
This method returns the ith simple root for the A series.
Examples
========
>>> from sympy.liealgebras.cartan_type import CartanType
>>> c = CartanType("A4")
>>> c.simple_root(1)
[1, -1, 0, 0, 0]
"""
return self.basic_root(i-1, i)
def positive_roots(self):
"""
This method generates all the positive roots of
A_n. This is half of all of the roots of A_n;
by multiplying all the positive roots by -1 we
get the negative roots.
Examples
========
>>> from sympy.liealgebras.cartan_type import CartanType
>>> c = CartanType("A3")
>>> c.positive_roots()
{1: [1, -1, 0, 0], 2: [1, 0, -1, 0], 3: [1, 0, 0, -1], 4: [0, 1, -1, 0],
5: [0, 1, 0, -1], 6: [0, 0, 1, -1]}
"""
n = self.n
posroots = {}
k = 0
for i in range(0, n):
for j in range(i+1, n+1):
k += 1
posroots[k] = self.basic_root(i, j)
return posroots
def highest_root(self):
"""
Returns the highest weight root for A_n
"""
return self.basic_root(0, self.n)
def roots(self):
"""
Returns the total number of roots for A_n
"""
n = self.n
return n*(n+1)
def cartan_matrix(self):
"""
Returns the Cartan matrix for A_n.
The Cartan matrix matrix for a Lie algebra is
generated by assigning an ordering to the simple
roots, (alpha[1], ...., alpha[l]). Then the ijth
entry of the Cartan matrix is (<alpha[i],alpha[j]>).
Examples
========
>>> from sympy.liealgebras.cartan_type import CartanType
>>> c = CartanType('A4')
>>> c.cartan_matrix()
Matrix([
[ 2, -1, 0, 0],
[-1, 2, -1, 0],
[ 0, -1, 2, -1],
[ 0, 0, -1, 2]])
"""
n = self.n
m = 2 * eye(n)
i = 1
while i < n-1:
m[i, i+1] = -1
m[i, i-1] = -1
i += 1
m[0,1] = -1
m[n-1, n-2] = -1
return m
def basis(self):
"""
Returns the number of independent generators of A_n
"""
n = self.n
return n**2 - 1
def lie_algebra(self):
"""
Returns the Lie algebra associated with A_n
"""
n = self.n
return "su(" + str(n + 1) + ")"
def dynkin_diagram(self):
n = self.n
diag = "---".join("0" for i in range(1, n+1)) + "\n"
diag += " ".join(str(i) for i in range(1, n+1))
return diag
PK ]ZZZ��/�� � sympy/liealgebras/type_b.pyfrom .cartan_type import Standard_Cartan
from sympy.core.backend import eye
class TypeB(Standard_Cartan):
def __new__(cls, n):
if n < 2:
raise ValueError("n cannot be less than 2")
return Standard_Cartan.__new__(cls, "B", n)
def dimension(self):
"""Dimension of the vector space V underlying the Lie algebra
Examples
========
>>> from sympy.liealgebras.cartan_type import CartanType
>>> c = CartanType("B3")
>>> c.dimension()
3
"""
return self.n
def basic_root(self, i, j):
"""
This is a method just to generate roots
with a 1 iin the ith position and a -1
in the jth position.
"""
root = [0]*self.n
root[i] = 1
root[j] = -1
return root
def simple_root(self, i):
"""
Every lie algebra has a unique root system.
Given a root system Q, there is a subset of the
roots such that an element of Q is called a
simple root if it cannot be written as the sum
of two elements in Q. If we let D denote the
set of simple roots, then it is clear that every
element of Q can be written as a linear combination
of elements of D with all coefficients non-negative.
In B_n the first n-1 simple roots are the same as the
roots in A_(n-1) (a 1 in the ith position, a -1 in
the (i+1)th position, and zeroes elsewhere). The n-th
simple root is the root with a 1 in the nth position
and zeroes elsewhere.
This method returns the ith simple root for the B series.
Examples
========
>>> from sympy.liealgebras.cartan_type import CartanType
>>> c = CartanType("B3")
>>> c.simple_root(2)
[0, 1, -1]
"""
n = self.n
if i < n:
return self.basic_root(i-1, i)
else:
root = [0]*self.n
root[n-1] = 1
return root
def positive_roots(self):
"""
This method generates all the positive roots of
A_n. This is half of all of the roots of B_n;
by multiplying all the positive roots by -1 we
get the negative roots.
Examples
========
>>> from sympy.liealgebras.cartan_type import CartanType
>>> c = CartanType("A3")
>>> c.positive_roots()
{1: [1, -1, 0, 0], 2: [1, 0, -1, 0], 3: [1, 0, 0, -1], 4: [0, 1, -1, 0],
5: [0, 1, 0, -1], 6: [0, 0, 1, -1]}
"""
n = self.n
posroots = {}
k = 0
for i in range(0, n-1):
for j in range(i+1, n):
k += 1
posroots[k] = self.basic_root(i, j)
k += 1
root = self.basic_root(i, j)
root[j] = 1
posroots[k] = root
for i in range(0, n):
k += 1
root = [0]*n
root[i] = 1
posroots[k] = root
return posroots
def roots(self):
"""
Returns the total number of roots for B_n"
"""
n = self.n
return 2*(n**2)
def cartan_matrix(self):
"""
Returns the Cartan matrix for B_n.
The Cartan matrix matrix for a Lie algebra is
generated by assigning an ordering to the simple
roots, (alpha[1], ...., alpha[l]). Then the ijth
entry of the Cartan matrix is (<alpha[i],alpha[j]>).
Examples
========
>>> from sympy.liealgebras.cartan_type import CartanType
>>> c = CartanType('B4')
>>> c.cartan_matrix()
Matrix([
[ 2, -1, 0, 0],
[-1, 2, -1, 0],
[ 0, -1, 2, -2],
[ 0, 0, -1, 2]])
"""
n = self.n
m = 2* eye(n)
i = 1
while i < n-1:
m[i, i+1] = -1
m[i, i-1] = -1
i += 1
m[0, 1] = -1
m[n-2, n-1] = -2
m[n-1, n-2] = -1
return m
def basis(self):
"""
Returns the number of independent generators of B_n
"""
n = self.n
return (n**2 - n)/2
def lie_algebra(self):
"""
Returns the Lie algebra associated with B_n
"""
n = self.n
return "so(" + str(2*n) + ")"
def dynkin_diagram(self):
n = self.n
diag = "---".join("0" for i in range(1, n)) + "=>=0\n"
diag += " ".join(str(i) for i in range(1, n+1))
return diag
PK ]ZZZY��/W W sympy/liealgebras/type_c.pyfrom .cartan_type import Standard_Cartan
from sympy.core.backend import eye
class TypeC(Standard_Cartan):
def __new__(cls, n):
if n < 3:
raise ValueError("n cannot be less than 3")
return Standard_Cartan.__new__(cls, "C", n)
def dimension(self):
"""Dimension of the vector space V underlying the Lie algebra
Examples
========
>>> from sympy.liealgebras.cartan_type import CartanType
>>> c = CartanType("C3")
>>> c.dimension()
3
"""
n = self.n
return n
def basic_root(self, i, j):
"""Generate roots with 1 in ith position and a -1 in jth position
"""
n = self.n
root = [0]*n
root[i] = 1
root[j] = -1
return root
def simple_root(self, i):
"""The ith simple root for the C series
Every lie algebra has a unique root system.
Given a root system Q, there is a subset of the
roots such that an element of Q is called a
simple root if it cannot be written as the sum
of two elements in Q. If we let D denote the
set of simple roots, then it is clear that every
element of Q can be written as a linear combination
of elements of D with all coefficients non-negative.
In C_n, the first n-1 simple roots are the same as
the roots in A_(n-1) (a 1 in the ith position, a -1
in the (i+1)th position, and zeroes elsewhere). The
nth simple root is the root in which there is a 2 in
the nth position and zeroes elsewhere.
Examples
========
>>> from sympy.liealgebras.cartan_type import CartanType
>>> c = CartanType("C3")
>>> c.simple_root(2)
[0, 1, -1]
"""
n = self.n
if i < n:
return self.basic_root(i-1,i)
else:
root = [0]*self.n
root[n-1] = 2
return root
def positive_roots(self):
"""Generates all the positive roots of A_n
This is half of all of the roots of C_n; by multiplying all the
positive roots by -1 we get the negative roots.
Examples
========
>>> from sympy.liealgebras.cartan_type import CartanType
>>> c = CartanType("A3")
>>> c.positive_roots()
{1: [1, -1, 0, 0], 2: [1, 0, -1, 0], 3: [1, 0, 0, -1], 4: [0, 1, -1, 0],
5: [0, 1, 0, -1], 6: [0, 0, 1, -1]}
"""
n = self.n
posroots = {}
k = 0
for i in range(0, n-1):
for j in range(i+1, n):
k += 1
posroots[k] = self.basic_root(i, j)
k += 1
root = self.basic_root(i, j)
root[j] = 1
posroots[k] = root
for i in range(0, n):
k += 1
root = [0]*n
root[i] = 2
posroots[k] = root
return posroots
def roots(self):
"""
Returns the total number of roots for C_n"
"""
n = self.n
return 2*(n**2)
def cartan_matrix(self):
"""The Cartan matrix for C_n
The Cartan matrix matrix for a Lie algebra is
generated by assigning an ordering to the simple
roots, (alpha[1], ...., alpha[l]). Then the ijth
entry of the Cartan matrix is (<alpha[i],alpha[j]>).
Examples
========
>>> from sympy.liealgebras.cartan_type import CartanType
>>> c = CartanType('C4')
>>> c.cartan_matrix()
Matrix([
[ 2, -1, 0, 0],
[-1, 2, -1, 0],
[ 0, -1, 2, -1],
[ 0, 0, -2, 2]])
"""
n = self.n
m = 2 * eye(n)
i = 1
while i < n-1:
m[i, i+1] = -1
m[i, i-1] = -1
i += 1
m[0,1] = -1
m[n-1, n-2] = -2
return m
def basis(self):
"""
Returns the number of independent generators of C_n
"""
n = self.n
return n*(2*n + 1)
def lie_algebra(self):
"""
Returns the Lie algebra associated with C_n"
"""
n = self.n
return "sp(" + str(2*n) + ")"
def dynkin_diagram(self):
n = self.n
diag = "---".join("0" for i in range(1, n)) + "=<=0\n"
diag += " ".join(str(i) for i in range(1, n+1))
return diag
PK ]ZZZ_��V V sympy/liealgebras/type_d.pyfrom .cartan_type import Standard_Cartan
from sympy.core.backend import eye
class TypeD(Standard_Cartan):
def __new__(cls, n):
if n < 3:
raise ValueError("n cannot be less than 3")
return Standard_Cartan.__new__(cls, "D", n)
def dimension(self):
"""Dmension of the vector space V underlying the Lie algebra
Examples
========
>>> from sympy.liealgebras.cartan_type import CartanType
>>> c = CartanType("D4")
>>> c.dimension()
4
"""
return self.n
def basic_root(self, i, j):
"""
This is a method just to generate roots
with a 1 iin the ith position and a -1
in the jth position.
"""
n = self.n
root = [0]*n
root[i] = 1
root[j] = -1
return root
def simple_root(self, i):
"""
Every lie algebra has a unique root system.
Given a root system Q, there is a subset of the
roots such that an element of Q is called a
simple root if it cannot be written as the sum
of two elements in Q. If we let D denote the
set of simple roots, then it is clear that every
element of Q can be written as a linear combination
of elements of D with all coefficients non-negative.
In D_n, the first n-1 simple roots are the same as
the roots in A_(n-1) (a 1 in the ith position, a -1
in the (i+1)th position, and zeroes elsewhere).
The nth simple root is the root in which there 1s in
the nth and (n-1)th positions, and zeroes elsewhere.
This method returns the ith simple root for the D series.
Examples
========
>>> from sympy.liealgebras.cartan_type import CartanType
>>> c = CartanType("D4")
>>> c.simple_root(2)
[0, 1, -1, 0]
"""
n = self.n
if i < n:
return self.basic_root(i-1, i)
else:
root = [0]*n
root[n-2] = 1
root[n-1] = 1
return root
def positive_roots(self):
"""
This method generates all the positive roots of
A_n. This is half of all of the roots of D_n
by multiplying all the positive roots by -1 we
get the negative roots.
Examples
========
>>> from sympy.liealgebras.cartan_type import CartanType
>>> c = CartanType("A3")
>>> c.positive_roots()
{1: [1, -1, 0, 0], 2: [1, 0, -1, 0], 3: [1, 0, 0, -1], 4: [0, 1, -1, 0],
5: [0, 1, 0, -1], 6: [0, 0, 1, -1]}
"""
n = self.n
posroots = {}
k = 0
for i in range(0, n-1):
for j in range(i+1, n):
k += 1
posroots[k] = self.basic_root(i, j)
k += 1
root = self.basic_root(i, j)
root[j] = 1
posroots[k] = root
return posroots
def roots(self):
"""
Returns the total number of roots for D_n"
"""
n = self.n
return 2*n*(n-1)
def cartan_matrix(self):
"""
Returns the Cartan matrix for D_n.
The Cartan matrix matrix for a Lie algebra is
generated by assigning an ordering to the simple
roots, (alpha[1], ...., alpha[l]). Then the ijth
entry of the Cartan matrix is (<alpha[i],alpha[j]>).
Examples
========
>>> from sympy.liealgebras.cartan_type import CartanType
>>> c = CartanType('D4')
>>> c.cartan_matrix()
Matrix([
[ 2, -1, 0, 0],
[-1, 2, -1, -1],
[ 0, -1, 2, 0],
[ 0, -1, 0, 2]])
"""
n = self.n
m = 2*eye(n)
i = 1
while i < n-2:
m[i,i+1] = -1
m[i,i-1] = -1
i += 1
m[n-2, n-3] = -1
m[n-3, n-1] = -1
m[n-1, n-3] = -1
m[0, 1] = -1
return m
def basis(self):
"""
Returns the number of independent generators of D_n
"""
n = self.n
return n*(n-1)/2
def lie_algebra(self):
"""
Returns the Lie algebra associated with D_n"
"""
n = self.n
return "so(" + str(2*n) + ")"
def dynkin_diagram(self):
n = self.n
diag = " "*4*(n-3) + str(n-1) + "\n"
diag += " "*4*(n-3) + "0\n"
diag += " "*4*(n-3) +"|\n"
diag += " "*4*(n-3) + "|\n"
diag += "---".join("0" for i in range(1,n)) + "\n"
diag += " ".join(str(i) for i in range(1, n-1)) + " "+str(n)
return diag
PK ]ZZZ5~?4& 4& sympy/liealgebras/type_e.pyfrom .cartan_type import Standard_Cartan
from sympy.core.backend import eye, Rational
class TypeE(Standard_Cartan):
def __new__(cls, n):
if n < 6 or n > 8:
raise ValueError("Invalid value of n")
return Standard_Cartan.__new__(cls, "E", n)
def dimension(self):
"""Dimension of the vector space V underlying the Lie algebra
Examples
========
>>> from sympy.liealgebras.cartan_type import CartanType
>>> c = CartanType("E6")
>>> c.dimension()
8
"""
return 8
def basic_root(self, i, j):
"""
This is a method just to generate roots
with a -1 in the ith position and a 1
in the jth position.
"""
root = [0]*8
root[i] = -1
root[j] = 1
return root
def simple_root(self, i):
"""
Every lie algebra has a unique root system.
Given a root system Q, there is a subset of the
roots such that an element of Q is called a
simple root if it cannot be written as the sum
of two elements in Q. If we let D denote the
set of simple roots, then it is clear that every
element of Q can be written as a linear combination
of elements of D with all coefficients non-negative.
This method returns the ith simple root for E_n.
Examples
========
>>> from sympy.liealgebras.cartan_type import CartanType
>>> c = CartanType("E6")
>>> c.simple_root(2)
[1, 1, 0, 0, 0, 0, 0, 0]
"""
n = self.n
if i == 1:
root = [-0.5]*8
root[0] = 0.5
root[7] = 0.5
return root
elif i == 2:
root = [0]*8
root[1] = 1
root[0] = 1
return root
else:
if i in (7, 8) and n == 6:
raise ValueError("E6 only has six simple roots!")
if i == 8 and n == 7:
raise ValueError("E7 has only 7 simple roots!")
return self.basic_root(i - 3, i - 2)
def positive_roots(self):
"""
This method generates all the positive roots of
A_n. This is half of all of the roots of E_n;
by multiplying all the positive roots by -1 we
get the negative roots.
Examples
========
>>> from sympy.liealgebras.cartan_type import CartanType
>>> c = CartanType("A3")
>>> c.positive_roots()
{1: [1, -1, 0, 0], 2: [1, 0, -1, 0], 3: [1, 0, 0, -1], 4: [0, 1, -1, 0],
5: [0, 1, 0, -1], 6: [0, 0, 1, -1]}
"""
n = self.n
if n == 6:
posroots = {}
k = 0
for i in range(n-1):
for j in range(i+1, n-1):
k += 1
root = self.basic_root(i, j)
posroots[k] = root
k += 1
root = self.basic_root(i, j)
root[i] = 1
posroots[k] = root
root = [Rational(1, 2), Rational(1, 2), Rational(1, 2), Rational(1, 2), Rational(1, 2),
Rational(-1, 2), Rational(-1, 2), Rational(1, 2)]
for a in range(0, 2):
for b in range(0, 2):
for c in range(0, 2):
for d in range(0, 2):
for e in range(0, 2):
if (a + b + c + d + e)%2 == 0:
k += 1
if a == 1:
root[0] = Rational(-1, 2)
if b == 1:
root[1] = Rational(-1, 2)
if c == 1:
root[2] = Rational(-1, 2)
if d == 1:
root[3] = Rational(-1, 2)
if e == 1:
root[4] = Rational(-1, 2)
posroots[k] = root
return posroots
if n == 7:
posroots = {}
k = 0
for i in range(n-1):
for j in range(i+1, n-1):
k += 1
root = self.basic_root(i, j)
posroots[k] = root
k += 1
root = self.basic_root(i, j)
root[i] = 1
posroots[k] = root
k += 1
posroots[k] = [0, 0, 0, 0, 0, 1, 1, 0]
root = [Rational(1, 2), Rational(1, 2), Rational(1, 2), Rational(1, 2), Rational(1, 2),
Rational(-1, 2), Rational(-1, 2), Rational(1, 2)]
for a in range(0, 2):
for b in range(0, 2):
for c in range(0, 2):
for d in range(0, 2):
for e in range(0, 2):
for f in range(0, 2):
if (a + b + c + d + e + f)%2 == 0:
k += 1
if a == 1:
root[0] = Rational(-1, 2)
if b == 1:
root[1] = Rational(-1, 2)
if c == 1:
root[2] = Rational(-1, 2)
if d == 1:
root[3] = Rational(-1, 2)
if e == 1:
root[4] = Rational(-1, 2)
if f == 1:
root[5] = Rational(1, 2)
posroots[k] = root
return posroots
if n == 8:
posroots = {}
k = 0
for i in range(n):
for j in range(i+1, n):
k += 1
root = self.basic_root(i, j)
posroots[k] = root
k += 1
root = self.basic_root(i, j)
root[i] = 1
posroots[k] = root
root = [Rational(1, 2), Rational(1, 2), Rational(1, 2), Rational(1, 2), Rational(1, 2),
Rational(-1, 2), Rational(-1, 2), Rational(1, 2)]
for a in range(0, 2):
for b in range(0, 2):
for c in range(0, 2):
for d in range(0, 2):
for e in range(0, 2):
for f in range(0, 2):
for g in range(0, 2):
if (a + b + c + d + e + f + g)%2 == 0:
k += 1
if a == 1:
root[0] = Rational(-1, 2)
if b == 1:
root[1] = Rational(-1, 2)
if c == 1:
root[2] = Rational(-1, 2)
if d == 1:
root[3] = Rational(-1, 2)
if e == 1:
root[4] = Rational(-1, 2)
if f == 1:
root[5] = Rational(1, 2)
if g == 1:
root[6] = Rational(1, 2)
posroots[k] = root
return posroots
def roots(self):
"""
Returns the total number of roots of E_n
"""
n = self.n
if n == 6:
return 72
if n == 7:
return 126
if n == 8:
return 240
def cartan_matrix(self):
"""
Returns the Cartan matrix for G_2
The Cartan matrix matrix for a Lie algebra is
generated by assigning an ordering to the simple
roots, (alpha[1], ...., alpha[l]). Then the ijth
entry of the Cartan matrix is (<alpha[i],alpha[j]>).
Examples
========
>>> from sympy.liealgebras.cartan_type import CartanType
>>> c = CartanType('A4')
>>> c.cartan_matrix()
Matrix([
[ 2, -1, 0, 0],
[-1, 2, -1, 0],
[ 0, -1, 2, -1],
[ 0, 0, -1, 2]])
"""
n = self.n
m = 2*eye(n)
i = 3
while i < n-1:
m[i, i+1] = -1
m[i, i-1] = -1
i += 1
m[0, 2] = m[2, 0] = -1
m[1, 3] = m[3, 1] = -1
m[2, 3] = -1
m[n-1, n-2] = -1
return m
def basis(self):
"""
Returns the number of independent generators of E_n
"""
n = self.n
if n == 6:
return 78
if n == 7:
return 133
if n == 8:
return 248
def dynkin_diagram(self):
n = self.n
diag = " "*8 + str(2) + "\n"
diag += " "*8 + "0\n"
diag += " "*8 + "|\n"
diag += " "*8 + "|\n"
diag += "---".join("0" for i in range(1, n)) + "\n"
diag += "1 " + " ".join(str(i) for i in range(3, n+1))
return diag
PK ]ZZZ}7jA A sympy/liealgebras/type_f.pyfrom .cartan_type import Standard_Cartan
from sympy.core.backend import Matrix, Rational
class TypeF(Standard_Cartan):
def __new__(cls, n):
if n != 4:
raise ValueError("n should be 4")
return Standard_Cartan.__new__(cls, "F", 4)
def dimension(self):
"""Dimension of the vector space V underlying the Lie algebra
Examples
========
>>> from sympy.liealgebras.cartan_type import CartanType
>>> c = CartanType("F4")
>>> c.dimension()
4
"""
return 4
def basic_root(self, i, j):
"""Generate roots with 1 in ith position and -1 in jth position
"""
n = self.n
root = [0]*n
root[i] = 1
root[j] = -1
return root
def simple_root(self, i):
"""The ith simple root of F_4
Every lie algebra has a unique root system.
Given a root system Q, there is a subset of the
roots such that an element of Q is called a
simple root if it cannot be written as the sum
of two elements in Q. If we let D denote the
set of simple roots, then it is clear that every
element of Q can be written as a linear combination
of elements of D with all coefficients non-negative.
Examples
========
>>> from sympy.liealgebras.cartan_type import CartanType
>>> c = CartanType("F4")
>>> c.simple_root(3)
[0, 0, 0, 1]
"""
if i < 3:
return self.basic_root(i-1, i)
if i == 3:
root = [0]*4
root[3] = 1
return root
if i == 4:
root = [Rational(-1, 2)]*4
return root
def positive_roots(self):
"""Generate all the positive roots of A_n
This is half of all of the roots of F_4; by multiplying all the
positive roots by -1 we get the negative roots.
Examples
========
>>> from sympy.liealgebras.cartan_type import CartanType
>>> c = CartanType("A3")
>>> c.positive_roots()
{1: [1, -1, 0, 0], 2: [1, 0, -1, 0], 3: [1, 0, 0, -1], 4: [0, 1, -1, 0],
5: [0, 1, 0, -1], 6: [0, 0, 1, -1]}
"""
n = self.n
posroots = {}
k = 0
for i in range(0, n-1):
for j in range(i+1, n):
k += 1
posroots[k] = self.basic_root(i, j)
k += 1
root = self.basic_root(i, j)
root[j] = 1
posroots[k] = root
for i in range(0, n):
k += 1
root = [0]*n
root[i] = 1
posroots[k] = root
k += 1
root = [Rational(1, 2)]*n
posroots[k] = root
for i in range(1, 4):
k += 1
root = [Rational(1, 2)]*n
root[i] = Rational(-1, 2)
posroots[k] = root
posroots[k+1] = [Rational(1, 2), Rational(1, 2), Rational(-1, 2), Rational(-1, 2)]
posroots[k+2] = [Rational(1, 2), Rational(-1, 2), Rational(1, 2), Rational(-1, 2)]
posroots[k+3] = [Rational(1, 2), Rational(-1, 2), Rational(-1, 2), Rational(1, 2)]
posroots[k+4] = [Rational(1, 2), Rational(-1, 2), Rational(-1, 2), Rational(-1, 2)]
return posroots
def roots(self):
"""
Returns the total number of roots for F_4
"""
return 48
def cartan_matrix(self):
"""The Cartan matrix for F_4
The Cartan matrix matrix for a Lie algebra is
generated by assigning an ordering to the simple
roots, (alpha[1], ...., alpha[l]). Then the ijth
entry of the Cartan matrix is (<alpha[i],alpha[j]>).
Examples
========
>>> from sympy.liealgebras.cartan_type import CartanType
>>> c = CartanType('A4')
>>> c.cartan_matrix()
Matrix([
[ 2, -1, 0, 0],
[-1, 2, -1, 0],
[ 0, -1, 2, -1],
[ 0, 0, -1, 2]])
"""
m = Matrix( 4, 4, [2, -1, 0, 0, -1, 2, -2, 0, 0,
-1, 2, -1, 0, 0, -1, 2])
return m
def basis(self):
"""
Returns the number of independent generators of F_4
"""
return 52
def dynkin_diagram(self):
diag = "0---0=>=0---0\n"
diag += " ".join(str(i) for i in range(1, 5))
return diag
PK ]ZZZP�c� � sympy/liealgebras/type_g.py# -*- coding: utf-8 -*-
from .cartan_type import Standard_Cartan
from sympy.core.backend import Matrix
class TypeG(Standard_Cartan):
def __new__(cls, n):
if n != 2:
raise ValueError("n should be 2")
return Standard_Cartan.__new__(cls, "G", 2)
def dimension(self):
"""Dimension of the vector space V underlying the Lie algebra
Examples
========
>>> from sympy.liealgebras.cartan_type import CartanType
>>> c = CartanType("G2")
>>> c.dimension()
3
"""
return 3
def simple_root(self, i):
"""The ith simple root of G_2
Every lie algebra has a unique root system.
Given a root system Q, there is a subset of the
roots such that an element of Q is called a
simple root if it cannot be written as the sum
of two elements in Q. If we let D denote the
set of simple roots, then it is clear that every
element of Q can be written as a linear combination
of elements of D with all coefficients non-negative.
Examples
========
>>> from sympy.liealgebras.cartan_type import CartanType
>>> c = CartanType("G2")
>>> c.simple_root(1)
[0, 1, -1]
"""
if i == 1:
return [0, 1, -1]
else:
return [1, -2, 1]
def positive_roots(self):
"""Generate all the positive roots of A_n
This is half of all of the roots of A_n; by multiplying all the
positive roots by -1 we get the negative roots.
Examples
========
>>> from sympy.liealgebras.cartan_type import CartanType
>>> c = CartanType("A3")
>>> c.positive_roots()
{1: [1, -1, 0, 0], 2: [1, 0, -1, 0], 3: [1, 0, 0, -1], 4: [0, 1, -1, 0],
5: [0, 1, 0, -1], 6: [0, 0, 1, -1]}
"""
roots = {1: [0, 1, -1], 2: [1, -2, 1], 3: [1, -1, 0], 4: [1, 0, 1],
5: [1, 1, -2], 6: [2, -1, -1]}
return roots
def roots(self):
"""
Returns the total number of roots of G_2"
"""
return 12
def cartan_matrix(self):
"""The Cartan matrix for G_2
The Cartan matrix matrix for a Lie algebra is
generated by assigning an ordering to the simple
roots, (alpha[1], ...., alpha[l]). Then the ijth
entry of the Cartan matrix is (<alpha[i],alpha[j]>).
Examples
========
>>> from sympy.liealgebras.cartan_type import CartanType
>>> c = CartanType("G2")
>>> c.cartan_matrix()
Matrix([
[ 2, -1],
[-3, 2]])
"""
m = Matrix( 2, 2, [2, -1, -3, 2])
return m
def basis(self):
"""
Returns the number of independent generators of G_2
"""
return 14
def dynkin_diagram(self):
diag = "0≡<≡0\n1 2"
return diag
PK ]ZZZ� � �8 �8 sympy/liealgebras/weyl_group.py# -*- coding: utf-8 -*-
from .cartan_type import CartanType
from mpmath import fac
from sympy.core.backend import Matrix, eye, Rational, igcd
from sympy.core.basic import Atom
class WeylGroup(Atom):
"""
For each semisimple Lie group, we have a Weyl group. It is a subgroup of
the isometry group of the root system. Specifically, it's the subgroup
that is generated by reflections through the hyperplanes orthogonal to
the roots. Therefore, Weyl groups are reflection groups, and so a Weyl
group is a finite Coxeter group.
"""
def __new__(cls, cartantype):
obj = Atom.__new__(cls)
obj.cartan_type = CartanType(cartantype)
return obj
def generators(self):
"""
This method creates the generating reflections of the Weyl group for
a given Lie algebra. For a Lie algebra of rank n, there are n
different generating reflections. This function returns them as
a list.
Examples
========
>>> from sympy.liealgebras.weyl_group import WeylGroup
>>> c = WeylGroup("F4")
>>> c.generators()
['r1', 'r2', 'r3', 'r4']
"""
n = self.cartan_type.rank()
generators = []
for i in range(1, n+1):
reflection = "r"+str(i)
generators.append(reflection)
return generators
def group_order(self):
"""
This method returns the order of the Weyl group.
For types A, B, C, D, and E the order depends on
the rank of the Lie algebra. For types F and G,
the order is fixed.
Examples
========
>>> from sympy.liealgebras.weyl_group import WeylGroup
>>> c = WeylGroup("D4")
>>> c.group_order()
192.0
"""
n = self.cartan_type.rank()
if self.cartan_type.series == "A":
return fac(n+1)
if self.cartan_type.series in ("B", "C"):
return fac(n)*(2**n)
if self.cartan_type.series == "D":
return fac(n)*(2**(n-1))
if self.cartan_type.series == "E":
if n == 6:
return 51840
if n == 7:
return 2903040
if n == 8:
return 696729600
if self.cartan_type.series == "F":
return 1152
if self.cartan_type.series == "G":
return 12
def group_name(self):
"""
This method returns some general information about the Weyl group for
a given Lie algebra. It returns the name of the group and the elements
it acts on, if relevant.
"""
n = self.cartan_type.rank()
if self.cartan_type.series == "A":
return "S"+str(n+1) + ": the symmetric group acting on " + str(n+1) + " elements."
if self.cartan_type.series in ("B", "C"):
return "The hyperoctahedral group acting on " + str(2*n) + " elements."
if self.cartan_type.series == "D":
return "The symmetry group of the " + str(n) + "-dimensional demihypercube."
if self.cartan_type.series == "E":
if n == 6:
return "The symmetry group of the 6-polytope."
if n == 7:
return "The symmetry group of the 7-polytope."
if n == 8:
return "The symmetry group of the 8-polytope."
if self.cartan_type.series == "F":
return "The symmetry group of the 24-cell, or icositetrachoron."
if self.cartan_type.series == "G":
return "D6, the dihedral group of order 12, and symmetry group of the hexagon."
def element_order(self, weylelt):
"""
This method returns the order of a given Weyl group element, which should
be specified by the user in the form of products of the generating
reflections, i.e. of the form r1*r2 etc.
For types A-F, this method current works by taking the matrix form of
the specified element, and then finding what power of the matrix is the
identity. It then returns this power.
Examples
========
>>> from sympy.liealgebras.weyl_group import WeylGroup
>>> b = WeylGroup("B4")
>>> b.element_order('r1*r4*r2')
4
"""
n = self.cartan_type.rank()
if self.cartan_type.series == "A":
a = self.matrix_form(weylelt)
order = 1
while a != eye(n+1):
a *= self.matrix_form(weylelt)
order += 1
return order
if self.cartan_type.series == "D":
a = self.matrix_form(weylelt)
order = 1
while a != eye(n):
a *= self.matrix_form(weylelt)
order += 1
return order
if self.cartan_type.series == "E":
a = self.matrix_form(weylelt)
order = 1
while a != eye(8):
a *= self.matrix_form(weylelt)
order += 1
return order
if self.cartan_type.series == "G":
elts = list(weylelt)
reflections = elts[1::3]
m = self.delete_doubles(reflections)
while self.delete_doubles(m) != m:
m = self.delete_doubles(m)
reflections = m
if len(reflections) % 2 == 1:
return 2
elif len(reflections) == 0:
return 1
else:
if len(reflections) == 1:
return 2
else:
m = len(reflections) // 2
lcm = (6 * m)/ igcd(m, 6)
order = lcm / m
return order
if self.cartan_type.series == 'F':
a = self.matrix_form(weylelt)
order = 1
while a != eye(4):
a *= self.matrix_form(weylelt)
order += 1
return order
if self.cartan_type.series in ("B", "C"):
a = self.matrix_form(weylelt)
order = 1
while a != eye(n):
a *= self.matrix_form(weylelt)
order += 1
return order
def delete_doubles(self, reflections):
"""
This is a helper method for determining the order of an element in the
Weyl group of G2. It takes a Weyl element and if repeated simple reflections
in it, it deletes them.
"""
counter = 0
copy = list(reflections)
for elt in copy:
if counter < len(copy)-1:
if copy[counter + 1] == elt:
del copy[counter]
del copy[counter]
counter += 1
return copy
def matrix_form(self, weylelt):
"""
This method takes input from the user in the form of products of the
generating reflections, and returns the matrix corresponding to the
element of the Weyl group. Since each element of the Weyl group is
a reflection of some type, there is a corresponding matrix representation.
This method uses the standard representation for all the generating
reflections.
Examples
========
>>> from sympy.liealgebras.weyl_group import WeylGroup
>>> f = WeylGroup("F4")
>>> f.matrix_form('r2*r3')
Matrix([
[1, 0, 0, 0],
[0, 1, 0, 0],
[0, 0, 0, -1],
[0, 0, 1, 0]])
"""
elts = list(weylelt)
reflections = elts[1::3]
n = self.cartan_type.rank()
if self.cartan_type.series == 'A':
matrixform = eye(n+1)
for elt in reflections:
a = int(elt)
mat = eye(n+1)
mat[a-1, a-1] = 0
mat[a-1, a] = 1
mat[a, a-1] = 1
mat[a, a] = 0
matrixform *= mat
return matrixform
if self.cartan_type.series == 'D':
matrixform = eye(n)
for elt in reflections:
a = int(elt)
mat = eye(n)
if a < n:
mat[a-1, a-1] = 0
mat[a-1, a] = 1
mat[a, a-1] = 1
mat[a, a] = 0
matrixform *= mat
else:
mat[n-2, n-1] = -1
mat[n-2, n-2] = 0
mat[n-1, n-2] = -1
mat[n-1, n-1] = 0
matrixform *= mat
return matrixform
if self.cartan_type.series == 'G':
matrixform = eye(3)
for elt in reflections:
a = int(elt)
if a == 1:
gen1 = Matrix([[1, 0, 0], [0, 0, 1], [0, 1, 0]])
matrixform *= gen1
else:
gen2 = Matrix([[Rational(2, 3), Rational(2, 3), Rational(-1, 3)],
[Rational(2, 3), Rational(-1, 3), Rational(2, 3)],
[Rational(-1, 3), Rational(2, 3), Rational(2, 3)]])
matrixform *= gen2
return matrixform
if self.cartan_type.series == 'F':
matrixform = eye(4)
for elt in reflections:
a = int(elt)
if a == 1:
mat = Matrix([[1, 0, 0, 0], [0, 0, 1, 0], [0, 1, 0, 0], [0, 0, 0, 1]])
matrixform *= mat
elif a == 2:
mat = Matrix([[1, 0, 0, 0], [0, 1, 0, 0], [0, 0, 0, 1], [0, 0, 1, 0]])
matrixform *= mat
elif a == 3:
mat = Matrix([[1, 0, 0, 0], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, -1]])
matrixform *= mat
else:
mat = Matrix([[Rational(1, 2), Rational(1, 2), Rational(1, 2), Rational(1, 2)],
[Rational(1, 2), Rational(1, 2), Rational(-1, 2), Rational(-1, 2)],
[Rational(1, 2), Rational(-1, 2), Rational(1, 2), Rational(-1, 2)],
[Rational(1, 2), Rational(-1, 2), Rational(-1, 2), Rational(1, 2)]])
matrixform *= mat
return matrixform
if self.cartan_type.series == 'E':
matrixform = eye(8)
for elt in reflections:
a = int(elt)
if a == 1:
mat = Matrix([[Rational(3, 4), Rational(1, 4), Rational(1, 4), Rational(1, 4),
Rational(1, 4), Rational(1, 4), Rational(1, 4), Rational(-1, 4)],
[Rational(1, 4), Rational(3, 4), Rational(-1, 4), Rational(-1, 4),
Rational(-1, 4), Rational(-1, 4), Rational(1, 4), Rational(-1, 4)],
[Rational(1, 4), Rational(-1, 4), Rational(3, 4), Rational(-1, 4),
Rational(-1, 4), Rational(-1, 4), Rational(-1, 4), Rational(1, 4)],
[Rational(1, 4), Rational(-1, 4), Rational(-1, 4), Rational(3, 4),
Rational(-1, 4), Rational(-1, 4), Rational(-1, 4), Rational(1, 4)],
[Rational(1, 4), Rational(-1, 4), Rational(-1, 4), Rational(-1, 4),
Rational(3, 4), Rational(-1, 4), Rational(-1, 4), Rational(1, 4)],
[Rational(1, 4), Rational(-1, 4), Rational(-1, 4), Rational(-1, 4),
Rational(-1, 4), Rational(3, 4), Rational(-1, 4), Rational(1, 4)],
[Rational(1, 4), Rational(-1, 4), Rational(-1, 4), Rational(-1, 4),
Rational(-1, 4), Rational(-1, 4), Rational(-3, 4), Rational(1, 4)],
[Rational(1, 4), Rational(-1, 4), Rational(-1, 4), Rational(-1, 4),
Rational(-1, 4), Rational(-1, 4), Rational(-1, 4), Rational(3, 4)]])
matrixform *= mat
elif a == 2:
mat = eye(8)
mat[0, 0] = 0
mat[0, 1] = -1
mat[1, 0] = -1
mat[1, 1] = 0
matrixform *= mat
else:
mat = eye(8)
mat[a-3, a-3] = 0
mat[a-3, a-2] = 1
mat[a-2, a-3] = 1
mat[a-2, a-2] = 0
matrixform *= mat
return matrixform
if self.cartan_type.series in ("B", "C"):
matrixform = eye(n)
for elt in reflections:
a = int(elt)
mat = eye(n)
if a == 1:
mat[0, 0] = -1
matrixform *= mat
else:
mat[a - 2, a - 2] = 0
mat[a-2, a-1] = 1
mat[a - 1, a - 2] = 1
mat[a -1, a - 1] = 0
matrixform *= mat
return matrixform
def coxeter_diagram(self):
"""
This method returns the Coxeter diagram corresponding to a Weyl group.
The Coxeter diagram can be obtained from a Lie algebra's Dynkin diagram
by deleting all arrows; the Coxeter diagram is the undirected graph.
The vertices of the Coxeter diagram represent the generating reflections
of the Weyl group, $s_i$. An edge is drawn between $s_i$ and $s_j$ if the order
$m(i, j)$ of $s_is_j$ is greater than two. If there is one edge, the order
$m(i, j)$ is 3. If there are two edges, the order $m(i, j)$ is 4, and if there
are three edges, the order $m(i, j)$ is 6.
Examples
========
>>> from sympy.liealgebras.weyl_group import WeylGroup
>>> c = WeylGroup("B3")
>>> print(c.coxeter_diagram())
0---0===0
1 2 3
"""
n = self.cartan_type.rank()
if self.cartan_type.series in ("A", "D", "E"):
return self.cartan_type.dynkin_diagram()
if self.cartan_type.series in ("B", "C"):
diag = "---".join("0" for i in range(1, n)) + "===0\n"
diag += " ".join(str(i) for i in range(1, n+1))
return diag
if self.cartan_type.series == "F":
diag = "0---0===0---0\n"
diag += " ".join(str(i) for i in range(1, 5))
return diag
if self.cartan_type.series == "G":
diag = "0≡≡≡0\n1 2"
return diag
PK ]ZZZԒ�,� � sympy/logic/__init__.pyfrom .boolalg import (to_cnf, to_dnf, to_nnf, And, Or, Not, Xor, Nand, Nor, Implies,
Equivalent, ITE, POSform, SOPform, simplify_logic, bool_map, true, false,
gateinputcount)
from .inference import satisfiable
__all__ = [
'to_cnf', 'to_dnf', 'to_nnf', 'And', 'Or', 'Not', 'Xor', 'Nand', 'Nor',
'Implies', 'Equivalent', 'ITE', 'POSform', 'SOPform', 'simplify_logic',
'bool_map', 'true', 'false', 'gateinputcount',
'satisfiable',
]
PK ]ZZZr+}��� �� sympy/logic/boolalg.py"""
Boolean algebra module for SymPy
"""
from collections import defaultdict
from itertools import chain, combinations, product, permutations
from sympy.core.add import Add
from sympy.core.basic import Basic
from sympy.core.cache import cacheit
from sympy.core.containers import Tuple
from sympy.core.decorators import sympify_method_args, sympify_return
from sympy.core.function import Application, Derivative
from sympy.core.kind import BooleanKind, NumberKind
from sympy.core.numbers import Number
from sympy.core.operations import LatticeOp
from sympy.core.singleton import Singleton, S
from sympy.core.sorting import ordered
from sympy.core.sympify import _sympy_converter, _sympify, sympify
from sympy.utilities.iterables import sift, ibin
from sympy.utilities.misc import filldedent
def as_Boolean(e):
"""Like ``bool``, return the Boolean value of an expression, e,
which can be any instance of :py:class:`~.Boolean` or ``bool``.
Examples
========
>>> from sympy import true, false, nan
>>> from sympy.logic.boolalg import as_Boolean
>>> from sympy.abc import x
>>> as_Boolean(0) is false
True
>>> as_Boolean(1) is true
True
>>> as_Boolean(x)
x
>>> as_Boolean(2)
Traceback (most recent call last):
...
TypeError: expecting bool or Boolean, not `2`.
>>> as_Boolean(nan)
Traceback (most recent call last):
...
TypeError: expecting bool or Boolean, not `nan`.
"""
from sympy.core.symbol import Symbol
if e == True:
return true
if e == False:
return false
if isinstance(e, Symbol):
z = e.is_zero
if z is None:
return e
return false if z else true
if isinstance(e, Boolean):
return e
raise TypeError('expecting bool or Boolean, not `%s`.' % e)
@sympify_method_args
class Boolean(Basic):
"""A Boolean object is an object for which logic operations make sense."""
__slots__ = ()
kind = BooleanKind
@sympify_return([('other', 'Boolean')], NotImplemented)
def __and__(self, other):
return And(self, other)
__rand__ = __and__
@sympify_return([('other', 'Boolean')], NotImplemented)
def __or__(self, other):
return Or(self, other)
__ror__ = __or__
def __invert__(self):
"""Overloading for ~"""
return Not(self)
@sympify_return([('other', 'Boolean')], NotImplemented)
def __rshift__(self, other):
return Implies(self, other)
@sympify_return([('other', 'Boolean')], NotImplemented)
def __lshift__(self, other):
return Implies(other, self)
__rrshift__ = __lshift__
__rlshift__ = __rshift__
@sympify_return([('other', 'Boolean')], NotImplemented)
def __xor__(self, other):
return Xor(self, other)
__rxor__ = __xor__
def equals(self, other):
"""
Returns ``True`` if the given formulas have the same truth table.
For two formulas to be equal they must have the same literals.
Examples
========
>>> from sympy.abc import A, B, C
>>> from sympy import And, Or, Not
>>> (A >> B).equals(~B >> ~A)
True
>>> Not(And(A, B, C)).equals(And(Not(A), Not(B), Not(C)))
False
>>> Not(And(A, Not(A))).equals(Or(B, Not(B)))
False
"""
from sympy.logic.inference import satisfiable
from sympy.core.relational import Relational
if self.has(Relational) or other.has(Relational):
raise NotImplementedError('handling of relationals')
return self.atoms() == other.atoms() and \
not satisfiable(Not(Equivalent(self, other)))
def to_nnf(self, simplify=True):
# override where necessary
return self
def as_set(self):
"""
Rewrites Boolean expression in terms of real sets.
Examples
========
>>> from sympy import Symbol, Eq, Or, And
>>> x = Symbol('x', real=True)
>>> Eq(x, 0).as_set()
{0}
>>> (x > 0).as_set()
Interval.open(0, oo)
>>> And(-2 < x, x < 2).as_set()
Interval.open(-2, 2)
>>> Or(x < -2, 2 < x).as_set()
Union(Interval.open(-oo, -2), Interval.open(2, oo))
"""
from sympy.calculus.util import periodicity
from sympy.core.relational import Relational
free = self.free_symbols
if len(free) == 1:
x = free.pop()
if x.kind is NumberKind:
reps = {}
for r in self.atoms(Relational):
if periodicity(r, x) not in (0, None):
s = r._eval_as_set()
if s in (S.EmptySet, S.UniversalSet, S.Reals):
reps[r] = s.as_relational(x)
continue
raise NotImplementedError(filldedent('''
as_set is not implemented for relationals
with periodic solutions
'''))
new = self.subs(reps)
if new.func != self.func:
return new.as_set() # restart with new obj
else:
return new._eval_as_set()
return self._eval_as_set()
else:
raise NotImplementedError("Sorry, as_set has not yet been"
" implemented for multivariate"
" expressions")
@property
def binary_symbols(self):
from sympy.core.relational import Eq, Ne
return set().union(*[i.binary_symbols for i in self.args
if i.is_Boolean or i.is_Symbol
or isinstance(i, (Eq, Ne))])
def _eval_refine(self, assumptions):
from sympy.assumptions import ask
ret = ask(self, assumptions)
if ret is True:
return true
elif ret is False:
return false
return None
class BooleanAtom(Boolean):
"""
Base class of :py:class:`~.BooleanTrue` and :py:class:`~.BooleanFalse`.
"""
is_Boolean = True
is_Atom = True
_op_priority = 11 # higher than Expr
def simplify(self, *a, **kw):
return self
def expand(self, *a, **kw):
return self
@property
def canonical(self):
return self
def _noop(self, other=None):
raise TypeError('BooleanAtom not allowed in this context.')
__add__ = _noop
__radd__ = _noop
__sub__ = _noop
__rsub__ = _noop
__mul__ = _noop
__rmul__ = _noop
__pow__ = _noop
__rpow__ = _noop
__truediv__ = _noop
__rtruediv__ = _noop
__mod__ = _noop
__rmod__ = _noop
_eval_power = _noop
# /// drop when Py2 is no longer supported
def __lt__(self, other):
raise TypeError(filldedent('''
A Boolean argument can only be used in
Eq and Ne; all other relationals expect
real expressions.
'''))
__le__ = __lt__
__gt__ = __lt__
__ge__ = __lt__
# \\\
def _eval_simplify(self, **kwargs):
return self
class BooleanTrue(BooleanAtom, metaclass=Singleton):
"""
SymPy version of ``True``, a singleton that can be accessed via ``S.true``.
This is the SymPy version of ``True``, for use in the logic module. The
primary advantage of using ``true`` instead of ``True`` is that shorthand Boolean
operations like ``~`` and ``>>`` will work as expected on this class, whereas with
True they act bitwise on 1. Functions in the logic module will return this
class when they evaluate to true.
Notes
=====
There is liable to be some confusion as to when ``True`` should
be used and when ``S.true`` should be used in various contexts
throughout SymPy. An important thing to remember is that
``sympify(True)`` returns ``S.true``. This means that for the most
part, you can just use ``True`` and it will automatically be converted
to ``S.true`` when necessary, similar to how you can generally use 1
instead of ``S.One``.
The rule of thumb is:
"If the boolean in question can be replaced by an arbitrary symbolic
``Boolean``, like ``Or(x, y)`` or ``x > 1``, use ``S.true``.
Otherwise, use ``True``"
In other words, use ``S.true`` only on those contexts where the
boolean is being used as a symbolic representation of truth.
For example, if the object ends up in the ``.args`` of any expression,
then it must necessarily be ``S.true`` instead of ``True``, as
elements of ``.args`` must be ``Basic``. On the other hand,
``==`` is not a symbolic operation in SymPy, since it always returns
``True`` or ``False``, and does so in terms of structural equality
rather than mathematical, so it should return ``True``. The assumptions
system should use ``True`` and ``False``. Aside from not satisfying
the above rule of thumb, the assumptions system uses a three-valued logic
(``True``, ``False``, ``None``), whereas ``S.true`` and ``S.false``
represent a two-valued logic. When in doubt, use ``True``.
"``S.true == True is True``."
While "``S.true is True``" is ``False``, "``S.true == True``"
is ``True``, so if there is any doubt over whether a function or
expression will return ``S.true`` or ``True``, just use ``==``
instead of ``is`` to do the comparison, and it will work in either
case. Finally, for boolean flags, it's better to just use ``if x``
instead of ``if x is True``. To quote PEP 8:
Do not compare boolean values to ``True`` or ``False``
using ``==``.
* Yes: ``if greeting:``
* No: ``if greeting == True:``
* Worse: ``if greeting is True:``
Examples
========
>>> from sympy import sympify, true, false, Or
>>> sympify(True)
True
>>> _ is True, _ is true
(False, True)
>>> Or(true, false)
True
>>> _ is true
True
Python operators give a boolean result for true but a
bitwise result for True
>>> ~true, ~True # doctest: +SKIP
(False, -2)
>>> true >> true, True >> True
(True, 0)
See Also
========
sympy.logic.boolalg.BooleanFalse
"""
def __bool__(self):
return True
def __hash__(self):
return hash(True)
def __eq__(self, other):
if other is True:
return True
if other is False:
return False
return super().__eq__(other)
@property
def negated(self):
return false
def as_set(self):
"""
Rewrite logic operators and relationals in terms of real sets.
Examples
========
>>> from sympy import true
>>> true.as_set()
UniversalSet
"""
return S.UniversalSet
class BooleanFalse(BooleanAtom, metaclass=Singleton):
"""
SymPy version of ``False``, a singleton that can be accessed via ``S.false``.
This is the SymPy version of ``False``, for use in the logic module. The
primary advantage of using ``false`` instead of ``False`` is that shorthand
Boolean operations like ``~`` and ``>>`` will work as expected on this class,
whereas with ``False`` they act bitwise on 0. Functions in the logic module
will return this class when they evaluate to false.
Notes
======
See the notes section in :py:class:`sympy.logic.boolalg.BooleanTrue`
Examples
========
>>> from sympy import sympify, true, false, Or
>>> sympify(False)
False
>>> _ is False, _ is false
(False, True)
>>> Or(true, false)
True
>>> _ is true
True
Python operators give a boolean result for false but a
bitwise result for False
>>> ~false, ~False # doctest: +SKIP
(True, -1)
>>> false >> false, False >> False
(True, 0)
See Also
========
sympy.logic.boolalg.BooleanTrue
"""
def __bool__(self):
return False
def __hash__(self):
return hash(False)
def __eq__(self, other):
if other is True:
return False
if other is False:
return True
return super().__eq__(other)
@property
def negated(self):
return true
def as_set(self):
"""
Rewrite logic operators and relationals in terms of real sets.
Examples
========
>>> from sympy import false
>>> false.as_set()
EmptySet
"""
return S.EmptySet
true = BooleanTrue()
false = BooleanFalse()
# We want S.true and S.false to work, rather than S.BooleanTrue and
# S.BooleanFalse, but making the class and instance names the same causes some
# major issues (like the inability to import the class directly from this
# file).
S.true = true
S.false = false
_sympy_converter[bool] = lambda x: true if x else false
class BooleanFunction(Application, Boolean):
"""Boolean function is a function that lives in a boolean space
It is used as base class for :py:class:`~.And`, :py:class:`~.Or`,
:py:class:`~.Not`, etc.
"""
is_Boolean = True
def _eval_simplify(self, **kwargs):
rv = simplify_univariate(self)
if not isinstance(rv, BooleanFunction):
return rv.simplify(**kwargs)
rv = rv.func(*[a.simplify(**kwargs) for a in rv.args])
return simplify_logic(rv)
def simplify(self, **kwargs):
from sympy.simplify.simplify import simplify
return simplify(self, **kwargs)
def __lt__(self, other):
raise TypeError(filldedent('''
A Boolean argument can only be used in
Eq and Ne; all other relationals expect
real expressions.
'''))
__le__ = __lt__
__ge__ = __lt__
__gt__ = __lt__
@classmethod
def binary_check_and_simplify(self, *args):
return [as_Boolean(i) for i in args]
def to_nnf(self, simplify=True):
return self._to_nnf(*self.args, simplify=simplify)
def to_anf(self, deep=True):
return self._to_anf(*self.args, deep=deep)
@classmethod
def _to_nnf(cls, *args, **kwargs):
simplify = kwargs.get('simplify', True)
argset = set()
for arg in args:
if not is_literal(arg):
arg = arg.to_nnf(simplify)
if simplify:
if isinstance(arg, cls):
arg = arg.args
else:
arg = (arg,)
for a in arg:
if Not(a) in argset:
return cls.zero
argset.add(a)
else:
argset.add(arg)
return cls(*argset)
@classmethod
def _to_anf(cls, *args, **kwargs):
deep = kwargs.get('deep', True)
new_args = []
for arg in args:
if deep:
if not is_literal(arg) or isinstance(arg, Not):
arg = arg.to_anf(deep=deep)
new_args.append(arg)
return cls(*new_args, remove_true=False)
# the diff method below is copied from Expr class
def diff(self, *symbols, **assumptions):
assumptions.setdefault("evaluate", True)
return Derivative(self, *symbols, **assumptions)
def _eval_derivative(self, x):
if x in self.binary_symbols:
from sympy.core.relational import Eq
from sympy.functions.elementary.piecewise import Piecewise
return Piecewise(
(0, Eq(self.subs(x, 0), self.subs(x, 1))),
(1, True))
elif x in self.free_symbols:
# not implemented, see https://www.encyclopediaofmath.org/
# index.php/Boolean_differential_calculus
pass
else:
return S.Zero
class And(LatticeOp, BooleanFunction):
"""
Logical AND function.
It evaluates its arguments in order, returning false immediately
when an argument is false and true if they are all true.
Examples
========
>>> from sympy.abc import x, y
>>> from sympy import And
>>> x & y
x & y
Notes
=====
The ``&`` operator is provided as a convenience, but note that its use
here is different from its normal use in Python, which is bitwise
and. Hence, ``And(a, b)`` and ``a & b`` will produce different results if
``a`` and ``b`` are integers.
>>> And(x, y).subs(x, 1)
y
"""
zero = false
identity = true
nargs = None
@classmethod
def _new_args_filter(cls, args):
args = BooleanFunction.binary_check_and_simplify(*args)
args = LatticeOp._new_args_filter(args, And)
newargs = []
rel = set()
for x in ordered(args):
if x.is_Relational:
c = x.canonical
if c in rel:
continue
elif c.negated.canonical in rel:
return [false]
else:
rel.add(c)
newargs.append(x)
return newargs
def _eval_subs(self, old, new):
args = []
bad = None
for i in self.args:
try:
i = i.subs(old, new)
except TypeError:
# store TypeError
if bad is None:
bad = i
continue
if i == False:
return false
elif i != True:
args.append(i)
if bad is not None:
# let it raise
bad.subs(old, new)
# If old is And, replace the parts of the arguments with new if all
# are there
if isinstance(old, And):
old_set = set(old.args)
if old_set.issubset(args):
args = set(args) - old_set
args.add(new)
return self.func(*args)
def _eval_simplify(self, **kwargs):
from sympy.core.relational import Equality, Relational
from sympy.solvers.solveset import linear_coeffs
# standard simplify
rv = super()._eval_simplify(**kwargs)
if not isinstance(rv, And):
return rv
# simplify args that are equalities involving
# symbols so x == 0 & x == y -> x==0 & y == 0
Rel, nonRel = sift(rv.args, lambda i: isinstance(i, Relational),
binary=True)
if not Rel:
return rv
eqs, other = sift(Rel, lambda i: isinstance(i, Equality), binary=True)
measure = kwargs['measure']
if eqs:
ratio = kwargs['ratio']
reps = {}
sifted = {}
# group by length of free symbols
sifted = sift(ordered([
(i.free_symbols, i) for i in eqs]),
lambda x: len(x[0]))
eqs = []
nonlineqs = []
while 1 in sifted:
for free, e in sifted.pop(1):
x = free.pop()
if (e.lhs != x or x in e.rhs.free_symbols) and x not in reps:
try:
m, b = linear_coeffs(
Add(e.lhs, -e.rhs, evaluate=False), x)
enew = e.func(x, -b/m)
if measure(enew) <= ratio*measure(e):
e = enew
else:
eqs.append(e)
continue
except ValueError:
pass
if x in reps:
eqs.append(e.subs(x, reps[x]))
elif e.lhs == x and x not in e.rhs.free_symbols:
reps[x] = e.rhs
eqs.append(e)
else:
# x is not yet identified, but may be later
nonlineqs.append(e)
resifted = defaultdict(list)
for k in sifted:
for f, e in sifted[k]:
e = e.xreplace(reps)
f = e.free_symbols
resifted[len(f)].append((f, e))
sifted = resifted
for k in sifted:
eqs.extend([e for f, e in sifted[k]])
nonlineqs = [ei.subs(reps) for ei in nonlineqs]
other = [ei.subs(reps) for ei in other]
rv = rv.func(*([i.canonical for i in (eqs + nonlineqs + other)] + nonRel))
patterns = _simplify_patterns_and()
threeterm_patterns = _simplify_patterns_and3()
return _apply_patternbased_simplification(rv, patterns,
measure, false,
threeterm_patterns=threeterm_patterns)
def _eval_as_set(self):
from sympy.sets.sets import Intersection
return Intersection(*[arg.as_set() for arg in self.args])
def _eval_rewrite_as_Nor(self, *args, **kwargs):
return Nor(*[Not(arg) for arg in self.args])
def to_anf(self, deep=True):
if deep:
result = And._to_anf(*self.args, deep=deep)
return distribute_xor_over_and(result)
return self
class Or(LatticeOp, BooleanFunction):
"""
Logical OR function
It evaluates its arguments in order, returning true immediately
when an argument is true, and false if they are all false.
Examples
========
>>> from sympy.abc import x, y
>>> from sympy import Or
>>> x | y
x | y
Notes
=====
The ``|`` operator is provided as a convenience, but note that its use
here is different from its normal use in Python, which is bitwise
or. Hence, ``Or(a, b)`` and ``a | b`` will return different things if
``a`` and ``b`` are integers.
>>> Or(x, y).subs(x, 0)
y
"""
zero = true
identity = false
@classmethod
def _new_args_filter(cls, args):
newargs = []
rel = []
args = BooleanFunction.binary_check_and_simplify(*args)
for x in args:
if x.is_Relational:
c = x.canonical
if c in rel:
continue
nc = c.negated.canonical
if any(r == nc for r in rel):
return [true]
rel.append(c)
newargs.append(x)
return LatticeOp._new_args_filter(newargs, Or)
def _eval_subs(self, old, new):
args = []
bad = None
for i in self.args:
try:
i = i.subs(old, new)
except TypeError:
# store TypeError
if bad is None:
bad = i
continue
if i == True:
return true
elif i != False:
args.append(i)
if bad is not None:
# let it raise
bad.subs(old, new)
# If old is Or, replace the parts of the arguments with new if all
# are there
if isinstance(old, Or):
old_set = set(old.args)
if old_set.issubset(args):
args = set(args) - old_set
args.add(new)
return self.func(*args)
def _eval_as_set(self):
from sympy.sets.sets import Union
return Union(*[arg.as_set() for arg in self.args])
def _eval_rewrite_as_Nand(self, *args, **kwargs):
return Nand(*[Not(arg) for arg in self.args])
def _eval_simplify(self, **kwargs):
from sympy.core.relational import Le, Ge, Eq
lege = self.atoms(Le, Ge)
if lege:
reps = {i: self.func(
Eq(i.lhs, i.rhs), i.strict) for i in lege}
return self.xreplace(reps)._eval_simplify(**kwargs)
# standard simplify
rv = super()._eval_simplify(**kwargs)
if not isinstance(rv, Or):
return rv
patterns = _simplify_patterns_or()
return _apply_patternbased_simplification(rv, patterns,
kwargs['measure'], true)
def to_anf(self, deep=True):
args = range(1, len(self.args) + 1)
args = (combinations(self.args, j) for j in args)
args = chain.from_iterable(args) # powerset
args = (And(*arg) for arg in args)
args = (to_anf(x, deep=deep) if deep else x for x in args)
return Xor(*list(args), remove_true=False)
class Not(BooleanFunction):
"""
Logical Not function (negation)
Returns ``true`` if the statement is ``false`` or ``False``.
Returns ``false`` if the statement is ``true`` or ``True``.
Examples
========
>>> from sympy import Not, And, Or
>>> from sympy.abc import x, A, B
>>> Not(True)
False
>>> Not(False)
True
>>> Not(And(True, False))
True
>>> Not(Or(True, False))
False
>>> Not(And(And(True, x), Or(x, False)))
~x
>>> ~x
~x
>>> Not(And(Or(A, B), Or(~A, ~B)))
~((A | B) & (~A | ~B))
Notes
=====
- The ``~`` operator is provided as a convenience, but note that its use
here is different from its normal use in Python, which is bitwise
not. In particular, ``~a`` and ``Not(a)`` will be different if ``a`` is
an integer. Furthermore, since bools in Python subclass from ``int``,
``~True`` is the same as ``~1`` which is ``-2``, which has a boolean
value of True. To avoid this issue, use the SymPy boolean types
``true`` and ``false``.
- As of Python 3.12, the bitwise not operator ``~`` used on a
Python ``bool`` is deprecated and will emit a warning.
>>> from sympy import true
>>> ~True # doctest: +SKIP
-2
>>> ~true
False
"""
is_Not = True
@classmethod
def eval(cls, arg):
if isinstance(arg, Number) or arg in (True, False):
return false if arg else true
if arg.is_Not:
return arg.args[0]
# Simplify Relational objects.
if arg.is_Relational:
return arg.negated
def _eval_as_set(self):
"""
Rewrite logic operators and relationals in terms of real sets.
Examples
========
>>> from sympy import Not, Symbol
>>> x = Symbol('x')
>>> Not(x > 0).as_set()
Interval(-oo, 0)
"""
return self.args[0].as_set().complement(S.Reals)
def to_nnf(self, simplify=True):
if is_literal(self):
return self
expr = self.args[0]
func, args = expr.func, expr.args
if func == And:
return Or._to_nnf(*[Not(arg) for arg in args], simplify=simplify)
if func == Or:
return And._to_nnf(*[Not(arg) for arg in args], simplify=simplify)
if func == Implies:
a, b = args
return And._to_nnf(a, Not(b), simplify=simplify)
if func == Equivalent:
return And._to_nnf(Or(*args), Or(*[Not(arg) for arg in args]),
simplify=simplify)
if func == Xor:
result = []
for i in range(1, len(args)+1, 2):
for neg in combinations(args, i):
clause = [Not(s) if s in neg else s for s in args]
result.append(Or(*clause))
return And._to_nnf(*result, simplify=simplify)
if func == ITE:
a, b, c = args
return And._to_nnf(Or(a, Not(c)), Or(Not(a), Not(b)), simplify=simplify)
raise ValueError("Illegal operator %s in expression" % func)
def to_anf(self, deep=True):
return Xor._to_anf(true, self.args[0], deep=deep)
class Xor(BooleanFunction):
"""
Logical XOR (exclusive OR) function.
Returns True if an odd number of the arguments are True and the rest are
False.
Returns False if an even number of the arguments are True and the rest are
False.
Examples
========
>>> from sympy.logic.boolalg import Xor
>>> from sympy import symbols
>>> x, y = symbols('x y')
>>> Xor(True, False)
True
>>> Xor(True, True)
False
>>> Xor(True, False, True, True, False)
True
>>> Xor(True, False, True, False)
False
>>> x ^ y
x ^ y
Notes
=====
The ``^`` operator is provided as a convenience, but note that its use
here is different from its normal use in Python, which is bitwise xor. In
particular, ``a ^ b`` and ``Xor(a, b)`` will be different if ``a`` and
``b`` are integers.
>>> Xor(x, y).subs(y, 0)
x
"""
def __new__(cls, *args, remove_true=True, **kwargs):
argset = set()
obj = super().__new__(cls, *args, **kwargs)
for arg in obj._args:
if isinstance(arg, Number) or arg in (True, False):
if arg:
arg = true
else:
continue
if isinstance(arg, Xor):
for a in arg.args:
argset.remove(a) if a in argset else argset.add(a)
elif arg in argset:
argset.remove(arg)
else:
argset.add(arg)
rel = [(r, r.canonical, r.negated.canonical)
for r in argset if r.is_Relational]
odd = False # is number of complimentary pairs odd? start 0 -> False
remove = []
for i, (r, c, nc) in enumerate(rel):
for j in range(i + 1, len(rel)):
rj, cj = rel[j][:2]
if cj == nc:
odd = not odd
break
elif cj == c:
break
else:
continue
remove.append((r, rj))
if odd:
argset.remove(true) if true in argset else argset.add(true)
for a, b in remove:
argset.remove(a)
argset.remove(b)
if len(argset) == 0:
return false
elif len(argset) == 1:
return argset.pop()
elif True in argset and remove_true:
argset.remove(True)
return Not(Xor(*argset))
else:
obj._args = tuple(ordered(argset))
obj._argset = frozenset(argset)
return obj
# XXX: This should be cached on the object rather than using cacheit
# Maybe it can be computed in __new__?
@property # type: ignore
@cacheit
def args(self):
return tuple(ordered(self._argset))
def to_nnf(self, simplify=True):
args = []
for i in range(0, len(self.args)+1, 2):
for neg in combinations(self.args, i):
clause = [Not(s) if s in neg else s for s in self.args]
args.append(Or(*clause))
return And._to_nnf(*args, simplify=simplify)
def _eval_rewrite_as_Or(self, *args, **kwargs):
a = self.args
return Or(*[_convert_to_varsSOP(x, self.args)
for x in _get_odd_parity_terms(len(a))])
def _eval_rewrite_as_And(self, *args, **kwargs):
a = self.args
return And(*[_convert_to_varsPOS(x, self.args)
for x in _get_even_parity_terms(len(a))])
def _eval_simplify(self, **kwargs):
# as standard simplify uses simplify_logic which writes things as
# And and Or, we only simplify the partial expressions before using
# patterns
rv = self.func(*[a.simplify(**kwargs) for a in self.args])
rv = rv.to_anf()
if not isinstance(rv, Xor): # This shouldn't really happen here
return rv
patterns = _simplify_patterns_xor()
return _apply_patternbased_simplification(rv, patterns,
kwargs['measure'], None)
def _eval_subs(self, old, new):
# If old is Xor, replace the parts of the arguments with new if all
# are there
if isinstance(old, Xor):
old_set = set(old.args)
if old_set.issubset(self.args):
args = set(self.args) - old_set
args.add(new)
return self.func(*args)
class Nand(BooleanFunction):
"""
Logical NAND function.
It evaluates its arguments in order, giving True immediately if any
of them are False, and False if they are all True.
Returns True if any of the arguments are False
Returns False if all arguments are True
Examples
========
>>> from sympy.logic.boolalg import Nand
>>> from sympy import symbols
>>> x, y = symbols('x y')
>>> Nand(False, True)
True
>>> Nand(True, True)
False
>>> Nand(x, y)
~(x & y)
"""
@classmethod
def eval(cls, *args):
return Not(And(*args))
class Nor(BooleanFunction):
"""
Logical NOR function.
It evaluates its arguments in order, giving False immediately if any
of them are True, and True if they are all False.
Returns False if any argument is True
Returns True if all arguments are False
Examples
========
>>> from sympy.logic.boolalg import Nor
>>> from sympy import symbols
>>> x, y = symbols('x y')
>>> Nor(True, False)
False
>>> Nor(True, True)
False
>>> Nor(False, True)
False
>>> Nor(False, False)
True
>>> Nor(x, y)
~(x | y)
"""
@classmethod
def eval(cls, *args):
return Not(Or(*args))
class Xnor(BooleanFunction):
"""
Logical XNOR function.
Returns False if an odd number of the arguments are True and the rest are
False.
Returns True if an even number of the arguments are True and the rest are
False.
Examples
========
>>> from sympy.logic.boolalg import Xnor
>>> from sympy import symbols
>>> x, y = symbols('x y')
>>> Xnor(True, False)
False
>>> Xnor(True, True)
True
>>> Xnor(True, False, True, True, False)
False
>>> Xnor(True, False, True, False)
True
"""
@classmethod
def eval(cls, *args):
return Not(Xor(*args))
class Implies(BooleanFunction):
r"""
Logical implication.
A implies B is equivalent to if A then B. Mathematically, it is written
as `A \Rightarrow B` and is equivalent to `\neg A \vee B` or ``~A | B``.
Accepts two Boolean arguments; A and B.
Returns False if A is True and B is False
Returns True otherwise.
Examples
========
>>> from sympy.logic.boolalg import Implies
>>> from sympy import symbols
>>> x, y = symbols('x y')
>>> Implies(True, False)
False
>>> Implies(False, False)
True
>>> Implies(True, True)
True
>>> Implies(False, True)
True
>>> x >> y
Implies(x, y)
>>> y << x
Implies(x, y)
Notes
=====
The ``>>`` and ``<<`` operators are provided as a convenience, but note
that their use here is different from their normal use in Python, which is
bit shifts. Hence, ``Implies(a, b)`` and ``a >> b`` will return different
things if ``a`` and ``b`` are integers. In particular, since Python
considers ``True`` and ``False`` to be integers, ``True >> True`` will be
the same as ``1 >> 1``, i.e., 0, which has a truth value of False. To
avoid this issue, use the SymPy objects ``true`` and ``false``.
>>> from sympy import true, false
>>> True >> False
1
>>> true >> false
False
"""
@classmethod
def eval(cls, *args):
try:
newargs = []
for x in args:
if isinstance(x, Number) or x in (0, 1):
newargs.append(bool(x))
else:
newargs.append(x)
A, B = newargs
except ValueError:
raise ValueError(
"%d operand(s) used for an Implies "
"(pairs are required): %s" % (len(args), str(args)))
if A in (True, False) or B in (True, False):
return Or(Not(A), B)
elif A == B:
return true
elif A.is_Relational and B.is_Relational:
if A.canonical == B.canonical:
return true
if A.negated.canonical == B.canonical:
return B
else:
return Basic.__new__(cls, *args)
def to_nnf(self, simplify=True):
a, b = self.args
return Or._to_nnf(Not(a), b, simplify=simplify)
def to_anf(self, deep=True):
a, b = self.args
return Xor._to_anf(true, a, And(a, b), deep=deep)
class Equivalent(BooleanFunction):
"""
Equivalence relation.
``Equivalent(A, B)`` is True iff A and B are both True or both False.
Returns True if all of the arguments are logically equivalent.
Returns False otherwise.
For two arguments, this is equivalent to :py:class:`~.Xnor`.
Examples
========
>>> from sympy.logic.boolalg import Equivalent, And
>>> from sympy.abc import x
>>> Equivalent(False, False, False)
True
>>> Equivalent(True, False, False)
False
>>> Equivalent(x, And(x, True))
True
"""
def __new__(cls, *args, **options):
from sympy.core.relational import Relational
args = [_sympify(arg) for arg in args]
argset = set(args)
for x in args:
if isinstance(x, Number) or x in [True, False]: # Includes 0, 1
argset.discard(x)
argset.add(bool(x))
rel = []
for r in argset:
if isinstance(r, Relational):
rel.append((r, r.canonical, r.negated.canonical))
remove = []
for i, (r, c, nc) in enumerate(rel):
for j in range(i + 1, len(rel)):
rj, cj = rel[j][:2]
if cj == nc:
return false
elif cj == c:
remove.append((r, rj))
break
for a, b in remove:
argset.remove(a)
argset.remove(b)
argset.add(True)
if len(argset) <= 1:
return true
if True in argset:
argset.discard(True)
return And(*argset)
if False in argset:
argset.discard(False)
return And(*[Not(arg) for arg in argset])
_args = frozenset(argset)
obj = super().__new__(cls, _args)
obj._argset = _args
return obj
# XXX: This should be cached on the object rather than using cacheit
# Maybe it can be computed in __new__?
@property # type: ignore
@cacheit
def args(self):
return tuple(ordered(self._argset))
def to_nnf(self, simplify=True):
args = []
for a, b in zip(self.args, self.args[1:]):
args.append(Or(Not(a), b))
args.append(Or(Not(self.args[-1]), self.args[0]))
return And._to_nnf(*args, simplify=simplify)
def to_anf(self, deep=True):
a = And(*self.args)
b = And(*[to_anf(Not(arg), deep=False) for arg in self.args])
b = distribute_xor_over_and(b)
return Xor._to_anf(a, b, deep=deep)
class ITE(BooleanFunction):
"""
If-then-else clause.
``ITE(A, B, C)`` evaluates and returns the result of B if A is true
else it returns the result of C. All args must be Booleans.
From a logic gate perspective, ITE corresponds to a 2-to-1 multiplexer,
where A is the select signal.
Examples
========
>>> from sympy.logic.boolalg import ITE, And, Xor, Or
>>> from sympy.abc import x, y, z
>>> ITE(True, False, True)
False
>>> ITE(Or(True, False), And(True, True), Xor(True, True))
True
>>> ITE(x, y, z)
ITE(x, y, z)
>>> ITE(True, x, y)
x
>>> ITE(False, x, y)
y
>>> ITE(x, y, y)
y
Trying to use non-Boolean args will generate a TypeError:
>>> ITE(True, [], ())
Traceback (most recent call last):
...
TypeError: expecting bool, Boolean or ITE, not `[]`
"""
def __new__(cls, *args, **kwargs):
from sympy.core.relational import Eq, Ne
if len(args) != 3:
raise ValueError('expecting exactly 3 args')
a, b, c = args
# check use of binary symbols
if isinstance(a, (Eq, Ne)):
# in this context, we can evaluate the Eq/Ne
# if one arg is a binary symbol and the other
# is true/false
b, c = map(as_Boolean, (b, c))
bin_syms = set().union(*[i.binary_symbols for i in (b, c)])
if len(set(a.args) - bin_syms) == 1:
# one arg is a binary_symbols
_a = a
if a.lhs is true:
a = a.rhs
elif a.rhs is true:
a = a.lhs
elif a.lhs is false:
a = Not(a.rhs)
elif a.rhs is false:
a = Not(a.lhs)
else:
# binary can only equal True or False
a = false
if isinstance(_a, Ne):
a = Not(a)
else:
a, b, c = BooleanFunction.binary_check_and_simplify(
a, b, c)
rv = None
if kwargs.get('evaluate', True):
rv = cls.eval(a, b, c)
if rv is None:
rv = BooleanFunction.__new__(cls, a, b, c, evaluate=False)
return rv
@classmethod
def eval(cls, *args):
from sympy.core.relational import Eq, Ne
# do the args give a singular result?
a, b, c = args
if isinstance(a, (Ne, Eq)):
_a = a
if true in a.args:
a = a.lhs if a.rhs is true else a.rhs
elif false in a.args:
a = Not(a.lhs) if a.rhs is false else Not(a.rhs)
else:
_a = None
if _a is not None and isinstance(_a, Ne):
a = Not(a)
if a is true:
return b
if a is false:
return c
if b == c:
return b
else:
# or maybe the results allow the answer to be expressed
# in terms of the condition
if b is true and c is false:
return a
if b is false and c is true:
return Not(a)
if [a, b, c] != args:
return cls(a, b, c, evaluate=False)
def to_nnf(self, simplify=True):
a, b, c = self.args
return And._to_nnf(Or(Not(a), b), Or(a, c), simplify=simplify)
def _eval_as_set(self):
return self.to_nnf().as_set()
def _eval_rewrite_as_Piecewise(self, *args, **kwargs):
from sympy.functions.elementary.piecewise import Piecewise
return Piecewise((args[1], args[0]), (args[2], True))
class Exclusive(BooleanFunction):
"""
True if only one or no argument is true.
``Exclusive(A, B, C)`` is equivalent to ``~(A & B) & ~(A & C) & ~(B & C)``.
For two arguments, this is equivalent to :py:class:`~.Xor`.
Examples
========
>>> from sympy.logic.boolalg import Exclusive
>>> Exclusive(False, False, False)
True
>>> Exclusive(False, True, False)
True
>>> Exclusive(False, True, True)
False
"""
@classmethod
def eval(cls, *args):
and_args = []
for a, b in combinations(args, 2):
and_args.append(Not(And(a, b)))
return And(*and_args)
# end class definitions. Some useful methods
def conjuncts(expr):
"""Return a list of the conjuncts in ``expr``.
Examples
========
>>> from sympy.logic.boolalg import conjuncts
>>> from sympy.abc import A, B
>>> conjuncts(A & B)
frozenset({A, B})
>>> conjuncts(A | B)
frozenset({A | B})
"""
return And.make_args(expr)
def disjuncts(expr):
"""Return a list of the disjuncts in ``expr``.
Examples
========
>>> from sympy.logic.boolalg import disjuncts
>>> from sympy.abc import A, B
>>> disjuncts(A | B)
frozenset({A, B})
>>> disjuncts(A & B)
frozenset({A & B})
"""
return Or.make_args(expr)
def distribute_and_over_or(expr):
"""
Given a sentence ``expr`` consisting of conjunctions and disjunctions
of literals, return an equivalent sentence in CNF.
Examples
========
>>> from sympy.logic.boolalg import distribute_and_over_or, And, Or, Not
>>> from sympy.abc import A, B, C
>>> distribute_and_over_or(Or(A, And(Not(B), Not(C))))
(A | ~B) & (A | ~C)
"""
return _distribute((expr, And, Or))
def distribute_or_over_and(expr):
"""
Given a sentence ``expr`` consisting of conjunctions and disjunctions
of literals, return an equivalent sentence in DNF.
Note that the output is NOT simplified.
Examples
========
>>> from sympy.logic.boolalg import distribute_or_over_and, And, Or, Not
>>> from sympy.abc import A, B, C
>>> distribute_or_over_and(And(Or(Not(A), B), C))
(B & C) | (C & ~A)
"""
return _distribute((expr, Or, And))
def distribute_xor_over_and(expr):
"""
Given a sentence ``expr`` consisting of conjunction and
exclusive disjunctions of literals, return an
equivalent exclusive disjunction.
Note that the output is NOT simplified.
Examples
========
>>> from sympy.logic.boolalg import distribute_xor_over_and, And, Xor, Not
>>> from sympy.abc import A, B, C
>>> distribute_xor_over_and(And(Xor(Not(A), B), C))
(B & C) ^ (C & ~A)
"""
return _distribute((expr, Xor, And))
def _distribute(info):
"""
Distributes ``info[1]`` over ``info[2]`` with respect to ``info[0]``.
"""
if isinstance(info[0], info[2]):
for arg in info[0].args:
if isinstance(arg, info[1]):
conj = arg
break
else:
return info[0]
rest = info[2](*[a for a in info[0].args if a is not conj])
return info[1](*list(map(_distribute,
[(info[2](c, rest), info[1], info[2])
for c in conj.args])), remove_true=False)
elif isinstance(info[0], info[1]):
return info[1](*list(map(_distribute,
[(x, info[1], info[2])
for x in info[0].args])),
remove_true=False)
else:
return info[0]
def to_anf(expr, deep=True):
r"""
Converts expr to Algebraic Normal Form (ANF).
ANF is a canonical normal form, which means that two
equivalent formulas will convert to the same ANF.
A logical expression is in ANF if it has the form
.. math:: 1 \oplus a \oplus b \oplus ab \oplus abc
i.e. it can be:
- purely true,
- purely false,
- conjunction of variables,
- exclusive disjunction.
The exclusive disjunction can only contain true, variables
or conjunction of variables. No negations are permitted.
If ``deep`` is ``False``, arguments of the boolean
expression are considered variables, i.e. only the
top-level expression is converted to ANF.
Examples
========
>>> from sympy.logic.boolalg import And, Or, Not, Implies, Equivalent
>>> from sympy.logic.boolalg import to_anf
>>> from sympy.abc import A, B, C
>>> to_anf(Not(A))
A ^ True
>>> to_anf(And(Or(A, B), Not(C)))
A ^ B ^ (A & B) ^ (A & C) ^ (B & C) ^ (A & B & C)
>>> to_anf(Implies(Not(A), Equivalent(B, C)), deep=False)
True ^ ~A ^ (~A & (Equivalent(B, C)))
"""
expr = sympify(expr)
if is_anf(expr):
return expr
return expr.to_anf(deep=deep)
def to_nnf(expr, simplify=True):
"""
Converts ``expr`` to Negation Normal Form (NNF).
A logical expression is in NNF if it
contains only :py:class:`~.And`, :py:class:`~.Or` and :py:class:`~.Not`,
and :py:class:`~.Not` is applied only to literals.
If ``simplify`` is ``True``, the result contains no redundant clauses.
Examples
========
>>> from sympy.abc import A, B, C, D
>>> from sympy.logic.boolalg import Not, Equivalent, to_nnf
>>> to_nnf(Not((~A & ~B) | (C & D)))
(A | B) & (~C | ~D)
>>> to_nnf(Equivalent(A >> B, B >> A))
(A | ~B | (A & ~B)) & (B | ~A | (B & ~A))
"""
if is_nnf(expr, simplify):
return expr
return expr.to_nnf(simplify)
def to_cnf(expr, simplify=False, force=False):
"""
Convert a propositional logical sentence ``expr`` to conjunctive normal
form: ``((A | ~B | ...) & (B | C | ...) & ...)``.
If ``simplify`` is ``True``, ``expr`` is evaluated to its simplest CNF
form using the Quine-McCluskey algorithm; this may take a long
time. If there are more than 8 variables the ``force`` flag must be set
to ``True`` to simplify (default is ``False``).
Examples
========
>>> from sympy.logic.boolalg import to_cnf
>>> from sympy.abc import A, B, D
>>> to_cnf(~(A | B) | D)
(D | ~A) & (D | ~B)
>>> to_cnf((A | B) & (A | ~A), True)
A | B
"""
expr = sympify(expr)
if not isinstance(expr, BooleanFunction):
return expr
if simplify:
if not force and len(_find_predicates(expr)) > 8:
raise ValueError(filldedent('''
To simplify a logical expression with more
than 8 variables may take a long time and requires
the use of `force=True`.'''))
return simplify_logic(expr, 'cnf', True, force=force)
# Don't convert unless we have to
if is_cnf(expr):
return expr
expr = eliminate_implications(expr)
res = distribute_and_over_or(expr)
return res
def to_dnf(expr, simplify=False, force=False):
"""
Convert a propositional logical sentence ``expr`` to disjunctive normal
form: ``((A & ~B & ...) | (B & C & ...) | ...)``.
If ``simplify`` is ``True``, ``expr`` is evaluated to its simplest DNF form using
the Quine-McCluskey algorithm; this may take a long
time. If there are more than 8 variables, the ``force`` flag must be set to
``True`` to simplify (default is ``False``).
Examples
========
>>> from sympy.logic.boolalg import to_dnf
>>> from sympy.abc import A, B, C
>>> to_dnf(B & (A | C))
(A & B) | (B & C)
>>> to_dnf((A & B) | (A & ~B) | (B & C) | (~B & C), True)
A | C
"""
expr = sympify(expr)
if not isinstance(expr, BooleanFunction):
return expr
if simplify:
if not force and len(_find_predicates(expr)) > 8:
raise ValueError(filldedent('''
To simplify a logical expression with more
than 8 variables may take a long time and requires
the use of `force=True`.'''))
return simplify_logic(expr, 'dnf', True, force=force)
# Don't convert unless we have to
if is_dnf(expr):
return expr
expr = eliminate_implications(expr)
return distribute_or_over_and(expr)
def is_anf(expr):
r"""
Checks if ``expr`` is in Algebraic Normal Form (ANF).
A logical expression is in ANF if it has the form
.. math:: 1 \oplus a \oplus b \oplus ab \oplus abc
i.e. it is purely true, purely false, conjunction of
variables or exclusive disjunction. The exclusive
disjunction can only contain true, variables or
conjunction of variables. No negations are permitted.
Examples
========
>>> from sympy.logic.boolalg import And, Not, Xor, true, is_anf
>>> from sympy.abc import A, B, C
>>> is_anf(true)
True
>>> is_anf(A)
True
>>> is_anf(And(A, B, C))
True
>>> is_anf(Xor(A, Not(B)))
False
"""
expr = sympify(expr)
if is_literal(expr) and not isinstance(expr, Not):
return True
if isinstance(expr, And):
for arg in expr.args:
if not arg.is_Symbol:
return False
return True
elif isinstance(expr, Xor):
for arg in expr.args:
if isinstance(arg, And):
for a in arg.args:
if not a.is_Symbol:
return False
elif is_literal(arg):
if isinstance(arg, Not):
return False
else:
return False
return True
else:
return False
def is_nnf(expr, simplified=True):
"""
Checks if ``expr`` is in Negation Normal Form (NNF).
A logical expression is in NNF if it
contains only :py:class:`~.And`, :py:class:`~.Or` and :py:class:`~.Not`,
and :py:class:`~.Not` is applied only to literals.
If ``simplified`` is ``True``, checks if result contains no redundant clauses.
Examples
========
>>> from sympy.abc import A, B, C
>>> from sympy.logic.boolalg import Not, is_nnf
>>> is_nnf(A & B | ~C)
True
>>> is_nnf((A | ~A) & (B | C))
False
>>> is_nnf((A | ~A) & (B | C), False)
True
>>> is_nnf(Not(A & B) | C)
False
>>> is_nnf((A >> B) & (B >> A))
False
"""
expr = sympify(expr)
if is_literal(expr):
return True
stack = [expr]
while stack:
expr = stack.pop()
if expr.func in (And, Or):
if simplified:
args = expr.args
for arg in args:
if Not(arg) in args:
return False
stack.extend(expr.args)
elif not is_literal(expr):
return False
return True
def is_cnf(expr):
"""
Test whether or not an expression is in conjunctive normal form.
Examples
========
>>> from sympy.logic.boolalg import is_cnf
>>> from sympy.abc import A, B, C
>>> is_cnf(A | B | C)
True
>>> is_cnf(A & B & C)
True
>>> is_cnf((A & B) | C)
False
"""
return _is_form(expr, And, Or)
def is_dnf(expr):
"""
Test whether or not an expression is in disjunctive normal form.
Examples
========
>>> from sympy.logic.boolalg import is_dnf
>>> from sympy.abc import A, B, C
>>> is_dnf(A | B | C)
True
>>> is_dnf(A & B & C)
True
>>> is_dnf((A & B) | C)
True
>>> is_dnf(A & (B | C))
False
"""
return _is_form(expr, Or, And)
def _is_form(expr, function1, function2):
"""
Test whether or not an expression is of the required form.
"""
expr = sympify(expr)
vals = function1.make_args(expr) if isinstance(expr, function1) else [expr]
for lit in vals:
if isinstance(lit, function2):
vals2 = function2.make_args(lit) if isinstance(lit, function2) else [lit]
for l in vals2:
if is_literal(l) is False:
return False
elif is_literal(lit) is False:
return False
return True
def eliminate_implications(expr):
"""
Change :py:class:`~.Implies` and :py:class:`~.Equivalent` into
:py:class:`~.And`, :py:class:`~.Or`, and :py:class:`~.Not`.
That is, return an expression that is equivalent to ``expr``, but has only
``&``, ``|``, and ``~`` as logical
operators.
Examples
========
>>> from sympy.logic.boolalg import Implies, Equivalent, \
eliminate_implications
>>> from sympy.abc import A, B, C
>>> eliminate_implications(Implies(A, B))
B | ~A
>>> eliminate_implications(Equivalent(A, B))
(A | ~B) & (B | ~A)
>>> eliminate_implications(Equivalent(A, B, C))
(A | ~C) & (B | ~A) & (C | ~B)
"""
return to_nnf(expr, simplify=False)
def is_literal(expr):
"""
Returns True if expr is a literal, else False.
Examples
========
>>> from sympy import Or, Q
>>> from sympy.abc import A, B
>>> from sympy.logic.boolalg import is_literal
>>> is_literal(A)
True
>>> is_literal(~A)
True
>>> is_literal(Q.zero(A))
True
>>> is_literal(A + B)
True
>>> is_literal(Or(A, B))
False
"""
from sympy.assumptions import AppliedPredicate
if isinstance(expr, Not):
return is_literal(expr.args[0])
elif expr in (True, False) or isinstance(expr, AppliedPredicate) or expr.is_Atom:
return True
elif not isinstance(expr, BooleanFunction) and all(
(isinstance(expr, AppliedPredicate) or a.is_Atom) for a in expr.args):
return True
return False
def to_int_repr(clauses, symbols):
"""
Takes clauses in CNF format and puts them into an integer representation.
Examples
========
>>> from sympy.logic.boolalg import to_int_repr
>>> from sympy.abc import x, y
>>> to_int_repr([x | y, y], [x, y]) == [{1, 2}, {2}]
True
"""
# Convert the symbol list into a dict
symbols = dict(zip(symbols, range(1, len(symbols) + 1)))
def append_symbol(arg, symbols):
if isinstance(arg, Not):
return -symbols[arg.args[0]]
else:
return symbols[arg]
return [{append_symbol(arg, symbols) for arg in Or.make_args(c)}
for c in clauses]
def term_to_integer(term):
"""
Return an integer corresponding to the base-2 digits given by *term*.
Parameters
==========
term : a string or list of ones and zeros
Examples
========
>>> from sympy.logic.boolalg import term_to_integer
>>> term_to_integer([1, 0, 0])
4
>>> term_to_integer('100')
4
"""
return int(''.join(list(map(str, list(term)))), 2)
integer_to_term = ibin # XXX could delete?
def truth_table(expr, variables, input=True):
"""
Return a generator of all possible configurations of the input variables,
and the result of the boolean expression for those values.
Parameters
==========
expr : Boolean expression
variables : list of variables
input : bool (default ``True``)
Indicates whether to return the input combinations.
Examples
========
>>> from sympy.logic.boolalg import truth_table
>>> from sympy.abc import x,y
>>> table = truth_table(x >> y, [x, y])
>>> for t in table:
... print('{0} -> {1}'.format(*t))
[0, 0] -> True
[0, 1] -> True
[1, 0] -> False
[1, 1] -> True
>>> table = truth_table(x | y, [x, y])
>>> list(table)
[([0, 0], False), ([0, 1], True), ([1, 0], True), ([1, 1], True)]
If ``input`` is ``False``, ``truth_table`` returns only a list of truth values.
In this case, the corresponding input values of variables can be
deduced from the index of a given output.
>>> from sympy.utilities.iterables import ibin
>>> vars = [y, x]
>>> values = truth_table(x >> y, vars, input=False)
>>> values = list(values)
>>> values
[True, False, True, True]
>>> for i, value in enumerate(values):
... print('{0} -> {1}'.format(list(zip(
... vars, ibin(i, len(vars)))), value))
[(y, 0), (x, 0)] -> True
[(y, 0), (x, 1)] -> False
[(y, 1), (x, 0)] -> True
[(y, 1), (x, 1)] -> True
"""
variables = [sympify(v) for v in variables]
expr = sympify(expr)
if not isinstance(expr, BooleanFunction) and not is_literal(expr):
return
table = product((0, 1), repeat=len(variables))
for term in table:
value = expr.xreplace(dict(zip(variables, term)))
if input:
yield list(term), value
else:
yield value
def _check_pair(minterm1, minterm2):
"""
Checks if a pair of minterms differs by only one bit. If yes, returns
index, else returns `-1`.
"""
# Early termination seems to be faster than list comprehension,
# at least for large examples.
index = -1
for x, i in enumerate(minterm1): # zip(minterm1, minterm2) is slower
if i != minterm2[x]:
if index == -1:
index = x
else:
return -1
return index
def _convert_to_varsSOP(minterm, variables):
"""
Converts a term in the expansion of a function from binary to its
variable form (for SOP).
"""
temp = [variables[n] if val == 1 else Not(variables[n])
for n, val in enumerate(minterm) if val != 3]
return And(*temp)
def _convert_to_varsPOS(maxterm, variables):
"""
Converts a term in the expansion of a function from binary to its
variable form (for POS).
"""
temp = [variables[n] if val == 0 else Not(variables[n])
for n, val in enumerate(maxterm) if val != 3]
return Or(*temp)
def _convert_to_varsANF(term, variables):
"""
Converts a term in the expansion of a function from binary to its
variable form (for ANF).
Parameters
==========
term : list of 1's and 0's (complementation pattern)
variables : list of variables
"""
temp = [variables[n] for n, t in enumerate(term) if t == 1]
if not temp:
return true
return And(*temp)
def _get_odd_parity_terms(n):
"""
Returns a list of lists, with all possible combinations of n zeros and ones
with an odd number of ones.
"""
return [e for e in [ibin(i, n) for i in range(2**n)] if sum(e) % 2 == 1]
def _get_even_parity_terms(n):
"""
Returns a list of lists, with all possible combinations of n zeros and ones
with an even number of ones.
"""
return [e for e in [ibin(i, n) for i in range(2**n)] if sum(e) % 2 == 0]
def _simplified_pairs(terms):
"""
Reduces a set of minterms, if possible, to a simplified set of minterms
with one less variable in the terms using QM method.
"""
if not terms:
return []
simplified_terms = []
todo = list(range(len(terms)))
# Count number of ones as _check_pair can only potentially match if there
# is at most a difference of a single one
termdict = defaultdict(list)
for n, term in enumerate(terms):
ones = sum(1 for t in term if t == 1)
termdict[ones].append(n)
variables = len(terms[0])
for k in range(variables):
for i in termdict[k]:
for j in termdict[k+1]:
index = _check_pair(terms[i], terms[j])
if index != -1:
# Mark terms handled
todo[i] = todo[j] = None
# Copy old term
newterm = terms[i][:]
# Set differing position to don't care
newterm[index] = 3
# Add if not already there
if newterm not in simplified_terms:
simplified_terms.append(newterm)
if simplified_terms:
# Further simplifications only among the new terms
simplified_terms = _simplified_pairs(simplified_terms)
# Add remaining, non-simplified, terms
simplified_terms.extend([terms[i] for i in todo if i is not None])
return simplified_terms
def _rem_redundancy(l1, terms):
"""
After the truth table has been sufficiently simplified, use the prime
implicant table method to recognize and eliminate redundant pairs,
and return the essential arguments.
"""
if not terms:
return []
nterms = len(terms)
nl1 = len(l1)
# Create dominating matrix
dommatrix = [[0]*nl1 for n in range(nterms)]
colcount = [0]*nl1
rowcount = [0]*nterms
for primei, prime in enumerate(l1):
for termi, term in enumerate(terms):
# Check prime implicant covering term
if all(t == 3 or t == mt for t, mt in zip(prime, term)):
dommatrix[termi][primei] = 1
colcount[primei] += 1
rowcount[termi] += 1
# Keep track if anything changed
anythingchanged = True
# Then, go again
while anythingchanged:
anythingchanged = False
for rowi in range(nterms):
# Still non-dominated?
if rowcount[rowi]:
row = dommatrix[rowi]
for row2i in range(nterms):
# Still non-dominated?
if rowi != row2i and rowcount[rowi] and (rowcount[rowi] <= rowcount[row2i]):
row2 = dommatrix[row2i]
if all(row2[n] >= row[n] for n in range(nl1)):
# row2 dominating row, remove row2
rowcount[row2i] = 0
anythingchanged = True
for primei, prime in enumerate(row2):
if prime:
# Make corresponding entry 0
dommatrix[row2i][primei] = 0
colcount[primei] -= 1
colcache = {}
for coli in range(nl1):
# Still non-dominated?
if colcount[coli]:
if coli in colcache:
col = colcache[coli]
else:
col = [dommatrix[i][coli] for i in range(nterms)]
colcache[coli] = col
for col2i in range(nl1):
# Still non-dominated?
if coli != col2i and colcount[col2i] and (colcount[coli] >= colcount[col2i]):
if col2i in colcache:
col2 = colcache[col2i]
else:
col2 = [dommatrix[i][col2i] for i in range(nterms)]
colcache[col2i] = col2
if all(col[n] >= col2[n] for n in range(nterms)):
# col dominating col2, remove col2
colcount[col2i] = 0
anythingchanged = True
for termi, term in enumerate(col2):
if term and dommatrix[termi][col2i]:
# Make corresponding entry 0
dommatrix[termi][col2i] = 0
rowcount[termi] -= 1
if not anythingchanged:
# Heuristically select the prime implicant covering most terms
maxterms = 0
bestcolidx = -1
for coli in range(nl1):
s = colcount[coli]
if s > maxterms:
bestcolidx = coli
maxterms = s
# In case we found a prime implicant covering at least two terms
if bestcolidx != -1 and maxterms > 1:
for primei, prime in enumerate(l1):
if primei != bestcolidx:
for termi, term in enumerate(colcache[bestcolidx]):
if term and dommatrix[termi][primei]:
# Make corresponding entry 0
dommatrix[termi][primei] = 0
anythingchanged = True
rowcount[termi] -= 1
colcount[primei] -= 1
return [l1[i] for i in range(nl1) if colcount[i]]
def _input_to_binlist(inputlist, variables):
binlist = []
bits = len(variables)
for val in inputlist:
if isinstance(val, int):
binlist.append(ibin(val, bits))
elif isinstance(val, dict):
nonspecvars = list(variables)
for key in val.keys():
nonspecvars.remove(key)
for t in product((0, 1), repeat=len(nonspecvars)):
d = dict(zip(nonspecvars, t))
d.update(val)
binlist.append([d[v] for v in variables])
elif isinstance(val, (list, tuple)):
if len(val) != bits:
raise ValueError("Each term must contain {bits} bits as there are"
"\n{bits} variables (or be an integer)."
"".format(bits=bits))
binlist.append(list(val))
else:
raise TypeError("A term list can only contain lists,"
" ints or dicts.")
return binlist
def SOPform(variables, minterms, dontcares=None):
"""
The SOPform function uses simplified_pairs and a redundant group-
eliminating algorithm to convert the list of all input combos that
generate '1' (the minterms) into the smallest sum-of-products form.
The variables must be given as the first argument.
Return a logical :py:class:`~.Or` function (i.e., the "sum of products" or
"SOP" form) that gives the desired outcome. If there are inputs that can
be ignored, pass them as a list, too.
The result will be one of the (perhaps many) functions that satisfy
the conditions.
Examples
========
>>> from sympy.logic import SOPform
>>> from sympy import symbols
>>> w, x, y, z = symbols('w x y z')
>>> minterms = [[0, 0, 0, 1], [0, 0, 1, 1],
... [0, 1, 1, 1], [1, 0, 1, 1], [1, 1, 1, 1]]
>>> dontcares = [[0, 0, 0, 0], [0, 0, 1, 0], [0, 1, 0, 1]]
>>> SOPform([w, x, y, z], minterms, dontcares)
(y & z) | (~w & ~x)
The terms can also be represented as integers:
>>> minterms = [1, 3, 7, 11, 15]
>>> dontcares = [0, 2, 5]
>>> SOPform([w, x, y, z], minterms, dontcares)
(y & z) | (~w & ~x)
They can also be specified using dicts, which does not have to be fully
specified:
>>> minterms = [{w: 0, x: 1}, {y: 1, z: 1, x: 0}]
>>> SOPform([w, x, y, z], minterms)
(x & ~w) | (y & z & ~x)
Or a combination:
>>> minterms = [4, 7, 11, [1, 1, 1, 1]]
>>> dontcares = [{w : 0, x : 0, y: 0}, 5]
>>> SOPform([w, x, y, z], minterms, dontcares)
(w & y & z) | (~w & ~y) | (x & z & ~w)
See also
========
POSform
References
==========
.. [1] https://en.wikipedia.org/wiki/Quine-McCluskey_algorithm
.. [2] https://en.wikipedia.org/wiki/Don%27t-care_term
"""
if not minterms:
return false
variables = tuple(map(sympify, variables))
minterms = _input_to_binlist(minterms, variables)
dontcares = _input_to_binlist((dontcares or []), variables)
for d in dontcares:
if d in minterms:
raise ValueError('%s in minterms is also in dontcares' % d)
return _sop_form(variables, minterms, dontcares)
def _sop_form(variables, minterms, dontcares):
new = _simplified_pairs(minterms + dontcares)
essential = _rem_redundancy(new, minterms)
return Or(*[_convert_to_varsSOP(x, variables) for x in essential])
def POSform(variables, minterms, dontcares=None):
"""
The POSform function uses simplified_pairs and a redundant-group
eliminating algorithm to convert the list of all input combinations
that generate '1' (the minterms) into the smallest product-of-sums form.
The variables must be given as the first argument.
Return a logical :py:class:`~.And` function (i.e., the "product of sums"
or "POS" form) that gives the desired outcome. If there are inputs that can
be ignored, pass them as a list, too.
The result will be one of the (perhaps many) functions that satisfy
the conditions.
Examples
========
>>> from sympy.logic import POSform
>>> from sympy import symbols
>>> w, x, y, z = symbols('w x y z')
>>> minterms = [[0, 0, 0, 1], [0, 0, 1, 1], [0, 1, 1, 1],
... [1, 0, 1, 1], [1, 1, 1, 1]]
>>> dontcares = [[0, 0, 0, 0], [0, 0, 1, 0], [0, 1, 0, 1]]
>>> POSform([w, x, y, z], minterms, dontcares)
z & (y | ~w)
The terms can also be represented as integers:
>>> minterms = [1, 3, 7, 11, 15]
>>> dontcares = [0, 2, 5]
>>> POSform([w, x, y, z], minterms, dontcares)
z & (y | ~w)
They can also be specified using dicts, which does not have to be fully
specified:
>>> minterms = [{w: 0, x: 1}, {y: 1, z: 1, x: 0}]
>>> POSform([w, x, y, z], minterms)
(x | y) & (x | z) & (~w | ~x)
Or a combination:
>>> minterms = [4, 7, 11, [1, 1, 1, 1]]
>>> dontcares = [{w : 0, x : 0, y: 0}, 5]
>>> POSform([w, x, y, z], minterms, dontcares)
(w | x) & (y | ~w) & (z | ~y)
See also
========
SOPform
References
==========
.. [1] https://en.wikipedia.org/wiki/Quine-McCluskey_algorithm
.. [2] https://en.wikipedia.org/wiki/Don%27t-care_term
"""
if not minterms:
return false
variables = tuple(map(sympify, variables))
minterms = _input_to_binlist(minterms, variables)
dontcares = _input_to_binlist((dontcares or []), variables)
for d in dontcares:
if d in minterms:
raise ValueError('%s in minterms is also in dontcares' % d)
maxterms = []
for t in product((0, 1), repeat=len(variables)):
t = list(t)
if (t not in minterms) and (t not in dontcares):
maxterms.append(t)
new = _simplified_pairs(maxterms + dontcares)
essential = _rem_redundancy(new, maxterms)
return And(*[_convert_to_varsPOS(x, variables) for x in essential])
def ANFform(variables, truthvalues):
"""
The ANFform function converts the list of truth values to
Algebraic Normal Form (ANF).
The variables must be given as the first argument.
Return True, False, logical :py:class:`~.And` function (i.e., the
"Zhegalkin monomial") or logical :py:class:`~.Xor` function (i.e.,
the "Zhegalkin polynomial"). When True and False
are represented by 1 and 0, respectively, then
:py:class:`~.And` is multiplication and :py:class:`~.Xor` is addition.
Formally a "Zhegalkin monomial" is the product (logical
And) of a finite set of distinct variables, including
the empty set whose product is denoted 1 (True).
A "Zhegalkin polynomial" is the sum (logical Xor) of a
set of Zhegalkin monomials, with the empty set denoted
by 0 (False).
Parameters
==========
variables : list of variables
truthvalues : list of 1's and 0's (result column of truth table)
Examples
========
>>> from sympy.logic.boolalg import ANFform
>>> from sympy.abc import x, y
>>> ANFform([x], [1, 0])
x ^ True
>>> ANFform([x, y], [0, 1, 1, 1])
x ^ y ^ (x & y)
References
==========
.. [1] https://en.wikipedia.org/wiki/Zhegalkin_polynomial
"""
n_vars = len(variables)
n_values = len(truthvalues)
if n_values != 2 ** n_vars:
raise ValueError("The number of truth values must be equal to 2^%d, "
"got %d" % (n_vars, n_values))
variables = tuple(map(sympify, variables))
coeffs = anf_coeffs(truthvalues)
terms = []
for i, t in enumerate(product((0, 1), repeat=n_vars)):
if coeffs[i] == 1:
terms.append(t)
return Xor(*[_convert_to_varsANF(x, variables) for x in terms],
remove_true=False)
def anf_coeffs(truthvalues):
"""
Convert a list of truth values of some boolean expression
to the list of coefficients of the polynomial mod 2 (exclusive
disjunction) representing the boolean expression in ANF
(i.e., the "Zhegalkin polynomial").
There are `2^n` possible Zhegalkin monomials in `n` variables, since
each monomial is fully specified by the presence or absence of
each variable.
We can enumerate all the monomials. For example, boolean
function with four variables ``(a, b, c, d)`` can contain
up to `2^4 = 16` monomials. The 13-th monomial is the
product ``a & b & d``, because 13 in binary is 1, 1, 0, 1.
A given monomial's presence or absence in a polynomial corresponds
to that monomial's coefficient being 1 or 0 respectively.
Examples
========
>>> from sympy.logic.boolalg import anf_coeffs, bool_monomial, Xor
>>> from sympy.abc import a, b, c
>>> truthvalues = [0, 1, 1, 0, 0, 1, 0, 1]
>>> coeffs = anf_coeffs(truthvalues)
>>> coeffs
[0, 1, 1, 0, 0, 0, 1, 0]
>>> polynomial = Xor(*[
... bool_monomial(k, [a, b, c])
... for k, coeff in enumerate(coeffs) if coeff == 1
... ])
>>> polynomial
b ^ c ^ (a & b)
"""
s = '{:b}'.format(len(truthvalues))
n = len(s) - 1
if len(truthvalues) != 2**n:
raise ValueError("The number of truth values must be a power of two, "
"got %d" % len(truthvalues))
coeffs = [[v] for v in truthvalues]
for i in range(n):
tmp = []
for j in range(2 ** (n-i-1)):
tmp.append(coeffs[2*j] +
list(map(lambda x, y: x^y, coeffs[2*j], coeffs[2*j+1])))
coeffs = tmp
return coeffs[0]
def bool_minterm(k, variables):
"""
Return the k-th minterm.
Minterms are numbered by a binary encoding of the complementation
pattern of the variables. This convention assigns the value 1 to
the direct form and 0 to the complemented form.
Parameters
==========
k : int or list of 1's and 0's (complementation pattern)
variables : list of variables
Examples
========
>>> from sympy.logic.boolalg import bool_minterm
>>> from sympy.abc import x, y, z
>>> bool_minterm([1, 0, 1], [x, y, z])
x & z & ~y
>>> bool_minterm(6, [x, y, z])
x & y & ~z
References
==========
.. [1] https://en.wikipedia.org/wiki/Canonical_normal_form#Indexing_minterms
"""
if isinstance(k, int):
k = ibin(k, len(variables))
variables = tuple(map(sympify, variables))
return _convert_to_varsSOP(k, variables)
def bool_maxterm(k, variables):
"""
Return the k-th maxterm.
Each maxterm is assigned an index based on the opposite
conventional binary encoding used for minterms. The maxterm
convention assigns the value 0 to the direct form and 1 to
the complemented form.
Parameters
==========
k : int or list of 1's and 0's (complementation pattern)
variables : list of variables
Examples
========
>>> from sympy.logic.boolalg import bool_maxterm
>>> from sympy.abc import x, y, z
>>> bool_maxterm([1, 0, 1], [x, y, z])
y | ~x | ~z
>>> bool_maxterm(6, [x, y, z])
z | ~x | ~y
References
==========
.. [1] https://en.wikipedia.org/wiki/Canonical_normal_form#Indexing_maxterms
"""
if isinstance(k, int):
k = ibin(k, len(variables))
variables = tuple(map(sympify, variables))
return _convert_to_varsPOS(k, variables)
def bool_monomial(k, variables):
"""
Return the k-th monomial.
Monomials are numbered by a binary encoding of the presence and
absences of the variables. This convention assigns the value
1 to the presence of variable and 0 to the absence of variable.
Each boolean function can be uniquely represented by a
Zhegalkin Polynomial (Algebraic Normal Form). The Zhegalkin
Polynomial of the boolean function with `n` variables can contain
up to `2^n` monomials. We can enumerate all the monomials.
Each monomial is fully specified by the presence or absence
of each variable.
For example, boolean function with four variables ``(a, b, c, d)``
can contain up to `2^4 = 16` monomials. The 13-th monomial is the
product ``a & b & d``, because 13 in binary is 1, 1, 0, 1.
Parameters
==========
k : int or list of 1's and 0's
variables : list of variables
Examples
========
>>> from sympy.logic.boolalg import bool_monomial
>>> from sympy.abc import x, y, z
>>> bool_monomial([1, 0, 1], [x, y, z])
x & z
>>> bool_monomial(6, [x, y, z])
x & y
"""
if isinstance(k, int):
k = ibin(k, len(variables))
variables = tuple(map(sympify, variables))
return _convert_to_varsANF(k, variables)
def _find_predicates(expr):
"""Helper to find logical predicates in BooleanFunctions.
A logical predicate is defined here as anything within a BooleanFunction
that is not a BooleanFunction itself.
"""
if not isinstance(expr, BooleanFunction):
return {expr}
return set().union(*(map(_find_predicates, expr.args)))
def simplify_logic(expr, form=None, deep=True, force=False, dontcare=None):
"""
This function simplifies a boolean function to its simplified version
in SOP or POS form. The return type is an :py:class:`~.Or` or
:py:class:`~.And` object in SymPy.
Parameters
==========
expr : Boolean
form : string (``'cnf'`` or ``'dnf'``) or ``None`` (default).
If ``'cnf'`` or ``'dnf'``, the simplest expression in the corresponding
normal form is returned; if ``None``, the answer is returned
according to the form with fewest args (in CNF by default).
deep : bool (default ``True``)
Indicates whether to recursively simplify any
non-boolean functions contained within the input.
force : bool (default ``False``)
As the simplifications require exponential time in the number
of variables, there is by default a limit on expressions with
8 variables. When the expression has more than 8 variables
only symbolical simplification (controlled by ``deep``) is
made. By setting ``force`` to ``True``, this limit is removed. Be
aware that this can lead to very long simplification times.
dontcare : Boolean
Optimize expression under the assumption that inputs where this
expression is true are don't care. This is useful in e.g. Piecewise
conditions, where later conditions do not need to consider inputs that
are converted by previous conditions. For example, if a previous
condition is ``And(A, B)``, the simplification of expr can be made
with don't cares for ``And(A, B)``.
Examples
========
>>> from sympy.logic import simplify_logic
>>> from sympy.abc import x, y, z
>>> b = (~x & ~y & ~z) | ( ~x & ~y & z)
>>> simplify_logic(b)
~x & ~y
>>> simplify_logic(x | y, dontcare=y)
x
References
==========
.. [1] https://en.wikipedia.org/wiki/Don%27t-care_term
"""
if form not in (None, 'cnf', 'dnf'):
raise ValueError("form can be cnf or dnf only")
expr = sympify(expr)
# check for quick exit if form is given: right form and all args are
# literal and do not involve Not
if form:
form_ok = False
if form == 'cnf':
form_ok = is_cnf(expr)
elif form == 'dnf':
form_ok = is_dnf(expr)
if form_ok and all(is_literal(a)
for a in expr.args):
return expr
from sympy.core.relational import Relational
if deep:
variables = expr.atoms(Relational)
from sympy.simplify.simplify import simplify
s = tuple(map(simplify, variables))
expr = expr.xreplace(dict(zip(variables, s)))
if not isinstance(expr, BooleanFunction):
return expr
# Replace Relationals with Dummys to possibly
# reduce the number of variables
repl = {}
undo = {}
from sympy.core.symbol import Dummy
variables = expr.atoms(Relational)
if dontcare is not None:
dontcare = sympify(dontcare)
variables.update(dontcare.atoms(Relational))
while variables:
var = variables.pop()
if var.is_Relational:
d = Dummy()
undo[d] = var
repl[var] = d
nvar = var.negated
if nvar in variables:
repl[nvar] = Not(d)
variables.remove(nvar)
expr = expr.xreplace(repl)
if dontcare is not None:
dontcare = dontcare.xreplace(repl)
# Get new variables after replacing
variables = _find_predicates(expr)
if not force and len(variables) > 8:
return expr.xreplace(undo)
if dontcare is not None:
# Add variables from dontcare
dcvariables = _find_predicates(dontcare)
variables.update(dcvariables)
# if too many restore to variables only
if not force and len(variables) > 8:
variables = _find_predicates(expr)
dontcare = None
# group into constants and variable values
c, v = sift(ordered(variables), lambda x: x in (True, False), binary=True)
variables = c + v
# standardize constants to be 1 or 0 in keeping with truthtable
c = [1 if i == True else 0 for i in c]
truthtable = _get_truthtable(v, expr, c)
if dontcare is not None:
dctruthtable = _get_truthtable(v, dontcare, c)
truthtable = [t for t in truthtable if t not in dctruthtable]
else:
dctruthtable = []
big = len(truthtable) >= (2 ** (len(variables) - 1))
if form == 'dnf' or form is None and big:
return _sop_form(variables, truthtable, dctruthtable).xreplace(undo)
return POSform(variables, truthtable, dctruthtable).xreplace(undo)
def _get_truthtable(variables, expr, const):
""" Return a list of all combinations leading to a True result for ``expr``.
"""
_variables = variables.copy()
def _get_tt(inputs):
if _variables:
v = _variables.pop()
tab = [[i[0].xreplace({v: false}), [0] + i[1]] for i in inputs if i[0] is not false]
tab.extend([[i[0].xreplace({v: true}), [1] + i[1]] for i in inputs if i[0] is not false])
return _get_tt(tab)
return inputs
res = [const + k[1] for k in _get_tt([[expr, []]]) if k[0]]
if res == [[]]:
return []
else:
return res
def _finger(eq):
"""
Assign a 5-item fingerprint to each symbol in the equation:
[
# of times it appeared as a Symbol;
# of times it appeared as a Not(symbol);
# of times it appeared as a Symbol in an And or Or;
# of times it appeared as a Not(Symbol) in an And or Or;
a sorted tuple of tuples, (i, j, k), where i is the number of arguments
in an And or Or with which it appeared as a Symbol, and j is
the number of arguments that were Not(Symbol); k is the number
of times that (i, j) was seen.
]
Examples
========
>>> from sympy.logic.boolalg import _finger as finger
>>> from sympy import And, Or, Not, Xor, to_cnf, symbols
>>> from sympy.abc import a, b, x, y
>>> eq = Or(And(Not(y), a), And(Not(y), b), And(x, y))
>>> dict(finger(eq))
{(0, 0, 1, 0, ((2, 0, 1),)): [x],
(0, 0, 1, 0, ((2, 1, 1),)): [a, b],
(0, 0, 1, 2, ((2, 0, 1),)): [y]}
>>> dict(finger(x & ~y))
{(0, 1, 0, 0, ()): [y], (1, 0, 0, 0, ()): [x]}
In the following, the (5, 2, 6) means that there were 6 Or
functions in which a symbol appeared as itself amongst 5 arguments in
which there were also 2 negated symbols, e.g. ``(a0 | a1 | a2 | ~a3 | ~a4)``
is counted once for a0, a1 and a2.
>>> dict(finger(to_cnf(Xor(*symbols('a:5')))))
{(0, 0, 8, 8, ((5, 0, 1), (5, 2, 6), (5, 4, 1))): [a0, a1, a2, a3, a4]}
The equation must not have more than one level of nesting:
>>> dict(finger(And(Or(x, y), y)))
{(0, 0, 1, 0, ((2, 0, 1),)): [x], (1, 0, 1, 0, ((2, 0, 1),)): [y]}
>>> dict(finger(And(Or(x, And(a, x)), y)))
Traceback (most recent call last):
...
NotImplementedError: unexpected level of nesting
So y and x have unique fingerprints, but a and b do not.
"""
f = eq.free_symbols
d = dict(list(zip(f, [[0]*4 + [defaultdict(int)] for fi in f])))
for a in eq.args:
if a.is_Symbol:
d[a][0] += 1
elif a.is_Not:
d[a.args[0]][1] += 1
else:
o = len(a.args), sum(isinstance(ai, Not) for ai in a.args)
for ai in a.args:
if ai.is_Symbol:
d[ai][2] += 1
d[ai][-1][o] += 1
elif ai.is_Not:
d[ai.args[0]][3] += 1
else:
raise NotImplementedError('unexpected level of nesting')
inv = defaultdict(list)
for k, v in ordered(iter(d.items())):
v[-1] = tuple(sorted([i + (j,) for i, j in v[-1].items()]))
inv[tuple(v)].append(k)
return inv
def bool_map(bool1, bool2):
"""
Return the simplified version of *bool1*, and the mapping of variables
that makes the two expressions *bool1* and *bool2* represent the same
logical behaviour for some correspondence between the variables
of each.
If more than one mappings of this sort exist, one of them
is returned.
For example, ``And(x, y)`` is logically equivalent to ``And(a, b)`` for
the mapping ``{x: a, y: b}`` or ``{x: b, y: a}``.
If no such mapping exists, return ``False``.
Examples
========
>>> from sympy import SOPform, bool_map, Or, And, Not, Xor
>>> from sympy.abc import w, x, y, z, a, b, c, d
>>> function1 = SOPform([x, z, y],[[1, 0, 1], [0, 0, 1]])
>>> function2 = SOPform([a, b, c],[[1, 0, 1], [1, 0, 0]])
>>> bool_map(function1, function2)
(y & ~z, {y: a, z: b})
The results are not necessarily unique, but they are canonical. Here,
``(w, z)`` could be ``(a, d)`` or ``(d, a)``:
>>> eq = Or(And(Not(y), w), And(Not(y), z), And(x, y))
>>> eq2 = Or(And(Not(c), a), And(Not(c), d), And(b, c))
>>> bool_map(eq, eq2)
((x & y) | (w & ~y) | (z & ~y), {w: a, x: b, y: c, z: d})
>>> eq = And(Xor(a, b), c, And(c,d))
>>> bool_map(eq, eq.subs(c, x))
(c & d & (a | b) & (~a | ~b), {a: a, b: b, c: d, d: x})
"""
def match(function1, function2):
"""Return the mapping that equates variables between two
simplified boolean expressions if possible.
By "simplified" we mean that a function has been denested
and is either an And (or an Or) whose arguments are either
symbols (x), negated symbols (Not(x)), or Or (or an And) whose
arguments are only symbols or negated symbols. For example,
``And(x, Not(y), Or(w, Not(z)))``.
Basic.match is not robust enough (see issue 4835) so this is
a workaround that is valid for simplified boolean expressions
"""
# do some quick checks
if function1.__class__ != function2.__class__:
return None # maybe simplification makes them the same?
if len(function1.args) != len(function2.args):
return None # maybe simplification makes them the same?
if function1.is_Symbol:
return {function1: function2}
# get the fingerprint dictionaries
f1 = _finger(function1)
f2 = _finger(function2)
# more quick checks
if len(f1) != len(f2):
return False
# assemble the match dictionary if possible
matchdict = {}
for k in f1.keys():
if k not in f2:
return False
if len(f1[k]) != len(f2[k]):
return False
for i, x in enumerate(f1[k]):
matchdict[x] = f2[k][i]
return matchdict
a = simplify_logic(bool1)
b = simplify_logic(bool2)
m = match(a, b)
if m:
return a, m
return m
def _apply_patternbased_simplification(rv, patterns, measure,
dominatingvalue,
replacementvalue=None,
threeterm_patterns=None):
"""
Replace patterns of Relational
Parameters
==========
rv : Expr
Boolean expression
patterns : tuple
Tuple of tuples, with (pattern to simplify, simplified pattern) with
two terms.
measure : function
Simplification measure.
dominatingvalue : Boolean or ``None``
The dominating value for the function of consideration.
For example, for :py:class:`~.And` ``S.false`` is dominating.
As soon as one expression is ``S.false`` in :py:class:`~.And`,
the whole expression is ``S.false``.
replacementvalue : Boolean or ``None``, optional
The resulting value for the whole expression if one argument
evaluates to ``dominatingvalue``.
For example, for :py:class:`~.Nand` ``S.false`` is dominating, but
in this case the resulting value is ``S.true``. Default is ``None``.
If ``replacementvalue`` is ``None`` and ``dominatingvalue`` is not
``None``, ``replacementvalue = dominatingvalue``.
threeterm_patterns : tuple, optional
Tuple of tuples, with (pattern to simplify, simplified pattern) with
three terms.
"""
from sympy.core.relational import Relational, _canonical
if replacementvalue is None and dominatingvalue is not None:
replacementvalue = dominatingvalue
# Use replacement patterns for Relationals
Rel, nonRel = sift(rv.args, lambda i: isinstance(i, Relational),
binary=True)
if len(Rel) <= 1:
return rv
Rel, nonRealRel = sift(Rel, lambda i: not any(s.is_real is False
for s in i.free_symbols),
binary=True)
Rel = [i.canonical for i in Rel]
if threeterm_patterns and len(Rel) >= 3:
Rel = _apply_patternbased_threeterm_simplification(Rel,
threeterm_patterns, rv.func, dominatingvalue,
replacementvalue, measure)
Rel = _apply_patternbased_twoterm_simplification(Rel, patterns,
rv.func, dominatingvalue, replacementvalue, measure)
rv = rv.func(*([_canonical(i) for i in ordered(Rel)]
+ nonRel + nonRealRel))
return rv
def _apply_patternbased_twoterm_simplification(Rel, patterns, func,
dominatingvalue,
replacementvalue,
measure):
""" Apply pattern-based two-term simplification."""
from sympy.functions.elementary.miscellaneous import Min, Max
from sympy.core.relational import Ge, Gt, _Inequality
changed = True
while changed and len(Rel) >= 2:
changed = False
# Use only < or <=
Rel = [r.reversed if isinstance(r, (Ge, Gt)) else r for r in Rel]
# Sort based on ordered
Rel = list(ordered(Rel))
# Eq and Ne must be tested reversed as well
rtmp = [(r, ) if isinstance(r, _Inequality) else (r, r.reversed) for r in Rel]
# Create a list of possible replacements
results = []
# Try all combinations of possibly reversed relational
for ((i, pi), (j, pj)) in combinations(enumerate(rtmp), 2):
for pattern, simp in patterns:
res = []
for p1, p2 in product(pi, pj):
# use SymPy matching
oldexpr = Tuple(p1, p2)
tmpres = oldexpr.match(pattern)
if tmpres:
res.append((tmpres, oldexpr))
if res:
for tmpres, oldexpr in res:
# we have a matching, compute replacement
np = simp.xreplace(tmpres)
if np == dominatingvalue:
# if dominatingvalue, the whole expression
# will be replacementvalue
return [replacementvalue]
# add replacement
if not isinstance(np, ITE) and not np.has(Min, Max):
# We only want to use ITE and Min/Max replacements if
# they simplify to a relational
costsaving = measure(func(*oldexpr.args)) - measure(np)
if costsaving > 0:
results.append((costsaving, ([i, j], np)))
if results:
# Sort results based on complexity
results = sorted(results,
key=lambda pair: pair[0], reverse=True)
# Replace the one providing most simplification
replacement = results[0][1]
idx, newrel = replacement
idx.sort()
# Remove the old relationals
for index in reversed(idx):
del Rel[index]
if dominatingvalue is None or newrel != Not(dominatingvalue):
# Insert the new one (no need to insert a value that will
# not affect the result)
if newrel.func == func:
for a in newrel.args:
Rel.append(a)
else:
Rel.append(newrel)
# We did change something so try again
changed = True
return Rel
def _apply_patternbased_threeterm_simplification(Rel, patterns, func,
dominatingvalue,
replacementvalue,
measure):
""" Apply pattern-based three-term simplification."""
from sympy.functions.elementary.miscellaneous import Min, Max
from sympy.core.relational import Le, Lt, _Inequality
changed = True
while changed and len(Rel) >= 3:
changed = False
# Use only > or >=
Rel = [r.reversed if isinstance(r, (Le, Lt)) else r for r in Rel]
# Sort based on ordered
Rel = list(ordered(Rel))
# Create a list of possible replacements
results = []
# Eq and Ne must be tested reversed as well
rtmp = [(r, ) if isinstance(r, _Inequality) else (r, r.reversed) for r in Rel]
# Try all combinations of possibly reversed relational
for ((i, pi), (j, pj), (k, pk)) in permutations(enumerate(rtmp), 3):
for pattern, simp in patterns:
res = []
for p1, p2, p3 in product(pi, pj, pk):
# use SymPy matching
oldexpr = Tuple(p1, p2, p3)
tmpres = oldexpr.match(pattern)
if tmpres:
res.append((tmpres, oldexpr))
if res:
for tmpres, oldexpr in res:
# we have a matching, compute replacement
np = simp.xreplace(tmpres)
if np == dominatingvalue:
# if dominatingvalue, the whole expression
# will be replacementvalue
return [replacementvalue]
# add replacement
if not isinstance(np, ITE) and not np.has(Min, Max):
# We only want to use ITE and Min/Max replacements if
# they simplify to a relational
costsaving = measure(func(*oldexpr.args)) - measure(np)
if costsaving > 0:
results.append((costsaving, ([i, j, k], np)))
if results:
# Sort results based on complexity
results = sorted(results,
key=lambda pair: pair[0], reverse=True)
# Replace the one providing most simplification
replacement = results[0][1]
idx, newrel = replacement
idx.sort()
# Remove the old relationals
for index in reversed(idx):
del Rel[index]
if dominatingvalue is None or newrel != Not(dominatingvalue):
# Insert the new one (no need to insert a value that will
# not affect the result)
if newrel.func == func:
for a in newrel.args:
Rel.append(a)
else:
Rel.append(newrel)
# We did change something so try again
changed = True
return Rel
@cacheit
def _simplify_patterns_and():
""" Two-term patterns for And."""
from sympy.core import Wild
from sympy.core.relational import Eq, Ne, Ge, Gt, Le, Lt
from sympy.functions.elementary.complexes import Abs
from sympy.functions.elementary.miscellaneous import Min, Max
a = Wild('a')
b = Wild('b')
c = Wild('c')
# Relationals patterns should be in alphabetical order
# (pattern1, pattern2, simplified)
# Do not use Ge, Gt
_matchers_and = ((Tuple(Eq(a, b), Lt(a, b)), false),
#(Tuple(Eq(a, b), Lt(b, a)), S.false),
#(Tuple(Le(b, a), Lt(a, b)), S.false),
#(Tuple(Lt(b, a), Le(a, b)), S.false),
(Tuple(Lt(b, a), Lt(a, b)), false),
(Tuple(Eq(a, b), Le(b, a)), Eq(a, b)),
#(Tuple(Eq(a, b), Le(a, b)), Eq(a, b)),
#(Tuple(Le(b, a), Lt(b, a)), Gt(a, b)),
(Tuple(Le(b, a), Le(a, b)), Eq(a, b)),
#(Tuple(Le(b, a), Ne(a, b)), Gt(a, b)),
#(Tuple(Lt(b, a), Ne(a, b)), Gt(a, b)),
(Tuple(Le(a, b), Lt(a, b)), Lt(a, b)),
(Tuple(Le(a, b), Ne(a, b)), Lt(a, b)),
(Tuple(Lt(a, b), Ne(a, b)), Lt(a, b)),
# Sign
(Tuple(Eq(a, b), Eq(a, -b)), And(Eq(a, S.Zero), Eq(b, S.Zero))),
# Min/Max/ITE
(Tuple(Le(b, a), Le(c, a)), Ge(a, Max(b, c))),
(Tuple(Le(b, a), Lt(c, a)), ITE(b > c, Ge(a, b), Gt(a, c))),
(Tuple(Lt(b, a), Lt(c, a)), Gt(a, Max(b, c))),
(Tuple(Le(a, b), Le(a, c)), Le(a, Min(b, c))),
(Tuple(Le(a, b), Lt(a, c)), ITE(b < c, Le(a, b), Lt(a, c))),
(Tuple(Lt(a, b), Lt(a, c)), Lt(a, Min(b, c))),
(Tuple(Le(a, b), Le(c, a)), ITE(Eq(b, c), Eq(a, b), ITE(b < c, false, And(Le(a, b), Ge(a, c))))),
(Tuple(Le(c, a), Le(a, b)), ITE(Eq(b, c), Eq(a, b), ITE(b < c, false, And(Le(a, b), Ge(a, c))))),
(Tuple(Lt(a, b), Lt(c, a)), ITE(b < c, false, And(Lt(a, b), Gt(a, c)))),
(Tuple(Lt(c, a), Lt(a, b)), ITE(b < c, false, And(Lt(a, b), Gt(a, c)))),
(Tuple(Le(a, b), Lt(c, a)), ITE(b <= c, false, And(Le(a, b), Gt(a, c)))),
(Tuple(Le(c, a), Lt(a, b)), ITE(b <= c, false, And(Lt(a, b), Ge(a, c)))),
(Tuple(Eq(a, b), Eq(a, c)), ITE(Eq(b, c), Eq(a, b), false)),
(Tuple(Lt(a, b), Lt(-b, a)), ITE(b > 0, Lt(Abs(a), b), false)),
(Tuple(Le(a, b), Le(-b, a)), ITE(b >= 0, Le(Abs(a), b), false)),
)
return _matchers_and
@cacheit
def _simplify_patterns_and3():
""" Three-term patterns for And."""
from sympy.core import Wild
from sympy.core.relational import Eq, Ge, Gt
a = Wild('a')
b = Wild('b')
c = Wild('c')
# Relationals patterns should be in alphabetical order
# (pattern1, pattern2, pattern3, simplified)
# Do not use Le, Lt
_matchers_and = ((Tuple(Ge(a, b), Ge(b, c), Gt(c, a)), false),
(Tuple(Ge(a, b), Gt(b, c), Gt(c, a)), false),
(Tuple(Gt(a, b), Gt(b, c), Gt(c, a)), false),
# (Tuple(Ge(c, a), Gt(a, b), Gt(b, c)), S.false),
# Lower bound relations
# Commented out combinations that does not simplify
(Tuple(Ge(a, b), Ge(a, c), Ge(b, c)), And(Ge(a, b), Ge(b, c))),
(Tuple(Ge(a, b), Ge(a, c), Gt(b, c)), And(Ge(a, b), Gt(b, c))),
# (Tuple(Ge(a, b), Gt(a, c), Ge(b, c)), And(Ge(a, b), Ge(b, c))),
(Tuple(Ge(a, b), Gt(a, c), Gt(b, c)), And(Ge(a, b), Gt(b, c))),
# (Tuple(Gt(a, b), Ge(a, c), Ge(b, c)), And(Gt(a, b), Ge(b, c))),
(Tuple(Ge(a, c), Gt(a, b), Gt(b, c)), And(Gt(a, b), Gt(b, c))),
(Tuple(Ge(b, c), Gt(a, b), Gt(a, c)), And(Gt(a, b), Ge(b, c))),
(Tuple(Gt(a, b), Gt(a, c), Gt(b, c)), And(Gt(a, b), Gt(b, c))),
# Upper bound relations
# Commented out combinations that does not simplify
(Tuple(Ge(b, a), Ge(c, a), Ge(b, c)), And(Ge(c, a), Ge(b, c))),
(Tuple(Ge(b, a), Ge(c, a), Gt(b, c)), And(Ge(c, a), Gt(b, c))),
# (Tuple(Ge(b, a), Gt(c, a), Ge(b, c)), And(Gt(c, a), Ge(b, c))),
(Tuple(Ge(b, a), Gt(c, a), Gt(b, c)), And(Gt(c, a), Gt(b, c))),
# (Tuple(Gt(b, a), Ge(c, a), Ge(b, c)), And(Ge(c, a), Ge(b, c))),
(Tuple(Ge(c, a), Gt(b, a), Gt(b, c)), And(Ge(c, a), Gt(b, c))),
(Tuple(Ge(b, c), Gt(b, a), Gt(c, a)), And(Gt(c, a), Ge(b, c))),
(Tuple(Gt(b, a), Gt(c, a), Gt(b, c)), And(Gt(c, a), Gt(b, c))),
# Circular relation
(Tuple(Ge(a, b), Ge(b, c), Ge(c, a)), And(Eq(a, b), Eq(b, c))),
)
return _matchers_and
@cacheit
def _simplify_patterns_or():
""" Two-term patterns for Or."""
from sympy.core import Wild
from sympy.core.relational import Eq, Ne, Ge, Gt, Le, Lt
from sympy.functions.elementary.complexes import Abs
from sympy.functions.elementary.miscellaneous import Min, Max
a = Wild('a')
b = Wild('b')
c = Wild('c')
# Relationals patterns should be in alphabetical order
# (pattern1, pattern2, simplified)
# Do not use Ge, Gt
_matchers_or = ((Tuple(Le(b, a), Le(a, b)), true),
#(Tuple(Le(b, a), Lt(a, b)), true),
(Tuple(Le(b, a), Ne(a, b)), true),
#(Tuple(Le(a, b), Lt(b, a)), true),
#(Tuple(Le(a, b), Ne(a, b)), true),
#(Tuple(Eq(a, b), Le(b, a)), Ge(a, b)),
#(Tuple(Eq(a, b), Lt(b, a)), Ge(a, b)),
(Tuple(Eq(a, b), Le(a, b)), Le(a, b)),
(Tuple(Eq(a, b), Lt(a, b)), Le(a, b)),
#(Tuple(Le(b, a), Lt(b, a)), Ge(a, b)),
(Tuple(Lt(b, a), Lt(a, b)), Ne(a, b)),
(Tuple(Lt(b, a), Ne(a, b)), Ne(a, b)),
(Tuple(Le(a, b), Lt(a, b)), Le(a, b)),
#(Tuple(Lt(a, b), Ne(a, b)), Ne(a, b)),
(Tuple(Eq(a, b), Ne(a, c)), ITE(Eq(b, c), true, Ne(a, c))),
(Tuple(Ne(a, b), Ne(a, c)), ITE(Eq(b, c), Ne(a, b), true)),
# Min/Max/ITE
(Tuple(Le(b, a), Le(c, a)), Ge(a, Min(b, c))),
#(Tuple(Ge(b, a), Ge(c, a)), Ge(Min(b, c), a)),
(Tuple(Le(b, a), Lt(c, a)), ITE(b > c, Lt(c, a), Le(b, a))),
(Tuple(Lt(b, a), Lt(c, a)), Gt(a, Min(b, c))),
#(Tuple(Gt(b, a), Gt(c, a)), Gt(Min(b, c), a)),
(Tuple(Le(a, b), Le(a, c)), Le(a, Max(b, c))),
#(Tuple(Le(b, a), Le(c, a)), Le(Max(b, c), a)),
(Tuple(Le(a, b), Lt(a, c)), ITE(b >= c, Le(a, b), Lt(a, c))),
(Tuple(Lt(a, b), Lt(a, c)), Lt(a, Max(b, c))),
#(Tuple(Lt(b, a), Lt(c, a)), Lt(Max(b, c), a)),
(Tuple(Le(a, b), Le(c, a)), ITE(b >= c, true, Or(Le(a, b), Ge(a, c)))),
(Tuple(Le(c, a), Le(a, b)), ITE(b >= c, true, Or(Le(a, b), Ge(a, c)))),
(Tuple(Lt(a, b), Lt(c, a)), ITE(b > c, true, Or(Lt(a, b), Gt(a, c)))),
(Tuple(Lt(c, a), Lt(a, b)), ITE(b > c, true, Or(Lt(a, b), Gt(a, c)))),
(Tuple(Le(a, b), Lt(c, a)), ITE(b >= c, true, Or(Le(a, b), Gt(a, c)))),
(Tuple(Le(c, a), Lt(a, b)), ITE(b >= c, true, Or(Lt(a, b), Ge(a, c)))),
(Tuple(Lt(b, a), Lt(a, -b)), ITE(b >= 0, Gt(Abs(a), b), true)),
(Tuple(Le(b, a), Le(a, -b)), ITE(b > 0, Ge(Abs(a), b), true)),
)
return _matchers_or
@cacheit
def _simplify_patterns_xor():
""" Two-term patterns for Xor."""
from sympy.functions.elementary.miscellaneous import Min, Max
from sympy.core import Wild
from sympy.core.relational import Eq, Ne, Ge, Gt, Le, Lt
a = Wild('a')
b = Wild('b')
c = Wild('c')
# Relationals patterns should be in alphabetical order
# (pattern1, pattern2, simplified)
# Do not use Ge, Gt
_matchers_xor = (#(Tuple(Le(b, a), Lt(a, b)), true),
#(Tuple(Lt(b, a), Le(a, b)), true),
#(Tuple(Eq(a, b), Le(b, a)), Gt(a, b)),
#(Tuple(Eq(a, b), Lt(b, a)), Ge(a, b)),
(Tuple(Eq(a, b), Le(a, b)), Lt(a, b)),
(Tuple(Eq(a, b), Lt(a, b)), Le(a, b)),
(Tuple(Le(a, b), Lt(a, b)), Eq(a, b)),
(Tuple(Le(a, b), Le(b, a)), Ne(a, b)),
(Tuple(Le(b, a), Ne(a, b)), Le(a, b)),
# (Tuple(Lt(b, a), Lt(a, b)), Ne(a, b)),
(Tuple(Lt(b, a), Ne(a, b)), Lt(a, b)),
# (Tuple(Le(a, b), Lt(a, b)), Eq(a, b)),
# (Tuple(Le(a, b), Ne(a, b)), Ge(a, b)),
# (Tuple(Lt(a, b), Ne(a, b)), Gt(a, b)),
# Min/Max/ITE
(Tuple(Le(b, a), Le(c, a)),
And(Ge(a, Min(b, c)), Lt(a, Max(b, c)))),
(Tuple(Le(b, a), Lt(c, a)),
ITE(b > c, And(Gt(a, c), Lt(a, b)),
And(Ge(a, b), Le(a, c)))),
(Tuple(Lt(b, a), Lt(c, a)),
And(Gt(a, Min(b, c)), Le(a, Max(b, c)))),
(Tuple(Le(a, b), Le(a, c)),
And(Le(a, Max(b, c)), Gt(a, Min(b, c)))),
(Tuple(Le(a, b), Lt(a, c)),
ITE(b < c, And(Lt(a, c), Gt(a, b)),
And(Le(a, b), Ge(a, c)))),
(Tuple(Lt(a, b), Lt(a, c)),
And(Lt(a, Max(b, c)), Ge(a, Min(b, c)))),
)
return _matchers_xor
def simplify_univariate(expr):
"""return a simplified version of univariate boolean expression, else ``expr``"""
from sympy.functions.elementary.piecewise import Piecewise
from sympy.core.relational import Eq, Ne
if not isinstance(expr, BooleanFunction):
return expr
if expr.atoms(Eq, Ne):
return expr
c = expr
free = c.free_symbols
if len(free) != 1:
return c
x = free.pop()
ok, i = Piecewise((0, c), evaluate=False
)._intervals(x, err_on_Eq=True)
if not ok:
return c
if not i:
return false
args = []
for a, b, _, _ in i:
if a is S.NegativeInfinity:
if b is S.Infinity:
c = true
else:
if c.subs(x, b) == True:
c = (x <= b)
else:
c = (x < b)
else:
incl_a = (c.subs(x, a) == True)
incl_b = (c.subs(x, b) == True)
if incl_a and incl_b:
if b.is_infinite:
c = (x >= a)
else:
c = And(a <= x, x <= b)
elif incl_a:
c = And(a <= x, x < b)
elif incl_b:
if b.is_infinite:
c = (x > a)
else:
c = And(a < x, x <= b)
else:
c = And(a < x, x < b)
args.append(c)
return Or(*args)
# Classes corresponding to logic gates
# Used in gateinputcount method
BooleanGates = (And, Or, Xor, Nand, Nor, Not, Xnor, ITE)
def gateinputcount(expr):
"""
Return the total number of inputs for the logic gates realizing the
Boolean expression.
Returns
=======
int
Number of gate inputs
Note
====
Not all Boolean functions count as gate here, only those that are
considered to be standard gates. These are: :py:class:`~.And`,
:py:class:`~.Or`, :py:class:`~.Xor`, :py:class:`~.Not`, and
:py:class:`~.ITE` (multiplexer). :py:class:`~.Nand`, :py:class:`~.Nor`,
and :py:class:`~.Xnor` will be evaluated to ``Not(And())`` etc.
Examples
========
>>> from sympy.logic import And, Or, Nand, Not, gateinputcount
>>> from sympy.abc import x, y, z
>>> expr = And(x, y)
>>> gateinputcount(expr)
2
>>> gateinputcount(Or(expr, z))
4
Note that ``Nand`` is automatically evaluated to ``Not(And())`` so
>>> gateinputcount(Nand(x, y, z))
4
>>> gateinputcount(Not(And(x, y, z)))
4
Although this can be avoided by using ``evaluate=False``
>>> gateinputcount(Nand(x, y, z, evaluate=False))
3
Also note that a comparison will count as a Boolean variable:
>>> gateinputcount(And(x > z, y >= 2))
2
As will a symbol:
>>> gateinputcount(x)
0
"""
if not isinstance(expr, Boolean):
raise TypeError("Expression must be Boolean")
if isinstance(expr, BooleanGates):
return len(expr.args) + sum(gateinputcount(x) for x in expr.args)
return 0
PK ]ZZZ�
�!# # sympy/logic/inference.py"""Inference in propositional logic"""
from sympy.logic.boolalg import And, Not, conjuncts, to_cnf, BooleanFunction
from sympy.core.sorting import ordered
from sympy.core.sympify import sympify
from sympy.external.importtools import import_module
def literal_symbol(literal):
"""
The symbol in this literal (without the negation).
Examples
========
>>> from sympy.abc import A
>>> from sympy.logic.inference import literal_symbol
>>> literal_symbol(A)
A
>>> literal_symbol(~A)
A
"""
if literal is True or literal is False:
return literal
elif literal.is_Symbol:
return literal
elif literal.is_Not:
return literal_symbol(literal.args[0])
else:
raise ValueError("Argument must be a boolean literal.")
def satisfiable(expr, algorithm=None, all_models=False, minimal=False, use_lra_theory=False):
"""
Check satisfiability of a propositional sentence.
Returns a model when it succeeds.
Returns {true: true} for trivially true expressions.
On setting all_models to True, if given expr is satisfiable then
returns a generator of models. However, if expr is unsatisfiable
then returns a generator containing the single element False.
Examples
========
>>> from sympy.abc import A, B
>>> from sympy.logic.inference import satisfiable
>>> satisfiable(A & ~B)
{A: True, B: False}
>>> satisfiable(A & ~A)
False
>>> satisfiable(True)
{True: True}
>>> next(satisfiable(A & ~A, all_models=True))
False
>>> models = satisfiable((A >> B) & B, all_models=True)
>>> next(models)
{A: False, B: True}
>>> next(models)
{A: True, B: True}
>>> def use_models(models):
... for model in models:
... if model:
... # Do something with the model.
... print(model)
... else:
... # Given expr is unsatisfiable.
... print("UNSAT")
>>> use_models(satisfiable(A >> ~A, all_models=True))
{A: False}
>>> use_models(satisfiable(A ^ A, all_models=True))
UNSAT
"""
if use_lra_theory:
if algorithm is not None and algorithm != "dpll2":
raise ValueError(f"Currently only dpll2 can handle using lra theory. {algorithm} is not handled.")
algorithm = "dpll2"
if algorithm is None or algorithm == "pycosat":
pycosat = import_module('pycosat')
if pycosat is not None:
algorithm = "pycosat"
else:
if algorithm == "pycosat":
raise ImportError("pycosat module is not present")
# Silently fall back to dpll2 if pycosat
# is not installed
algorithm = "dpll2"
if algorithm=="minisat22":
pysat = import_module('pysat')
if pysat is None:
algorithm = "dpll2"
if algorithm=="z3":
z3 = import_module('z3')
if z3 is None:
algorithm = "dpll2"
if algorithm == "dpll":
from sympy.logic.algorithms.dpll import dpll_satisfiable
return dpll_satisfiable(expr)
elif algorithm == "dpll2":
from sympy.logic.algorithms.dpll2 import dpll_satisfiable
return dpll_satisfiable(expr, all_models, use_lra_theory=use_lra_theory)
elif algorithm == "pycosat":
from sympy.logic.algorithms.pycosat_wrapper import pycosat_satisfiable
return pycosat_satisfiable(expr, all_models)
elif algorithm == "minisat22":
from sympy.logic.algorithms.minisat22_wrapper import minisat22_satisfiable
return minisat22_satisfiable(expr, all_models, minimal)
elif algorithm == "z3":
from sympy.logic.algorithms.z3_wrapper import z3_satisfiable
return z3_satisfiable(expr, all_models)
raise NotImplementedError
def valid(expr):
"""
Check validity of a propositional sentence.
A valid propositional sentence is True under every assignment.
Examples
========
>>> from sympy.abc import A, B
>>> from sympy.logic.inference import valid
>>> valid(A | ~A)
True
>>> valid(A | B)
False
References
==========
.. [1] https://en.wikipedia.org/wiki/Validity
"""
return not satisfiable(Not(expr))
def pl_true(expr, model=None, deep=False):
"""
Returns whether the given assignment is a model or not.
If the assignment does not specify the value for every proposition,
this may return None to indicate 'not obvious'.
Parameters
==========
model : dict, optional, default: {}
Mapping of symbols to boolean values to indicate assignment.
deep: boolean, optional, default: False
Gives the value of the expression under partial assignments
correctly. May still return None to indicate 'not obvious'.
Examples
========
>>> from sympy.abc import A, B
>>> from sympy.logic.inference import pl_true
>>> pl_true( A & B, {A: True, B: True})
True
>>> pl_true(A & B, {A: False})
False
>>> pl_true(A & B, {A: True})
>>> pl_true(A & B, {A: True}, deep=True)
>>> pl_true(A >> (B >> A))
>>> pl_true(A >> (B >> A), deep=True)
True
>>> pl_true(A & ~A)
>>> pl_true(A & ~A, deep=True)
False
>>> pl_true(A & B & (~A | ~B), {A: True})
>>> pl_true(A & B & (~A | ~B), {A: True}, deep=True)
False
"""
from sympy.core.symbol import Symbol
boolean = (True, False)
def _validate(expr):
if isinstance(expr, Symbol) or expr in boolean:
return True
if not isinstance(expr, BooleanFunction):
return False
return all(_validate(arg) for arg in expr.args)
if expr in boolean:
return expr
expr = sympify(expr)
if not _validate(expr):
raise ValueError("%s is not a valid boolean expression" % expr)
if not model:
model = {}
model = {k: v for k, v in model.items() if v in boolean}
result = expr.subs(model)
if result in boolean:
return bool(result)
if deep:
model = dict.fromkeys(result.atoms(), True)
if pl_true(result, model):
if valid(result):
return True
else:
if not satisfiable(result):
return False
return None
def entails(expr, formula_set=None):
"""
Check whether the given expr_set entail an expr.
If formula_set is empty then it returns the validity of expr.
Examples
========
>>> from sympy.abc import A, B, C
>>> from sympy.logic.inference import entails
>>> entails(A, [A >> B, B >> C])
False
>>> entails(C, [A >> B, B >> C, A])
True
>>> entails(A >> B)
False
>>> entails(A >> (B >> A))
True
References
==========
.. [1] https://en.wikipedia.org/wiki/Logical_consequence
"""
if formula_set:
formula_set = list(formula_set)
else:
formula_set = []
formula_set.append(Not(expr))
return not satisfiable(And(*formula_set))
class KB:
"""Base class for all knowledge bases"""
def __init__(self, sentence=None):
self.clauses_ = set()
if sentence:
self.tell(sentence)
def tell(self, sentence):
raise NotImplementedError
def ask(self, query):
raise NotImplementedError
def retract(self, sentence):
raise NotImplementedError
@property
def clauses(self):
return list(ordered(self.clauses_))
class PropKB(KB):
"""A KB for Propositional Logic. Inefficient, with no indexing."""
def tell(self, sentence):
"""Add the sentence's clauses to the KB
Examples
========
>>> from sympy.logic.inference import PropKB
>>> from sympy.abc import x, y
>>> l = PropKB()
>>> l.clauses
[]
>>> l.tell(x | y)
>>> l.clauses
[x | y]
>>> l.tell(y)
>>> l.clauses
[y, x | y]
"""
for c in conjuncts(to_cnf(sentence)):
self.clauses_.add(c)
def ask(self, query):
"""Checks if the query is true given the set of clauses.
Examples
========
>>> from sympy.logic.inference import PropKB
>>> from sympy.abc import x, y
>>> l = PropKB()
>>> l.tell(x & ~y)
>>> l.ask(x)
True
>>> l.ask(y)
False
"""
return entails(query, self.clauses_)
def retract(self, sentence):
"""Remove the sentence's clauses from the KB
Examples
========
>>> from sympy.logic.inference import PropKB
>>> from sympy.abc import x, y
>>> l = PropKB()
>>> l.clauses
[]
>>> l.tell(x | y)
>>> l.clauses
[x | y]
>>> l.retract(x | y)
>>> l.clauses
[]
"""
for c in conjuncts(to_cnf(sentence)):
self.clauses_.discard(c)
PK ]ZZZ " sympy/logic/algorithms/__init__.pyPK ]ZZZ\#�{�# �# sympy/logic/algorithms/dpll.py"""Implementation of DPLL algorithm
Further improvements: eliminate calls to pl_true, implement branching rules,
efficient unit propagation.
References:
- https://en.wikipedia.org/wiki/DPLL_algorithm
- https://www.researchgate.net/publication/242384772_Implementations_of_the_DPLL_Algorithm
"""
from sympy.core.sorting import default_sort_key
from sympy.logic.boolalg import Or, Not, conjuncts, disjuncts, to_cnf, \
to_int_repr, _find_predicates
from sympy.assumptions.cnf import CNF
from sympy.logic.inference import pl_true, literal_symbol
def dpll_satisfiable(expr):
"""
Check satisfiability of a propositional sentence.
It returns a model rather than True when it succeeds
>>> from sympy.abc import A, B
>>> from sympy.logic.algorithms.dpll import dpll_satisfiable
>>> dpll_satisfiable(A & ~B)
{A: True, B: False}
>>> dpll_satisfiable(A & ~A)
False
"""
if not isinstance(expr, CNF):
clauses = conjuncts(to_cnf(expr))
else:
clauses = expr.clauses
if False in clauses:
return False
symbols = sorted(_find_predicates(expr), key=default_sort_key)
symbols_int_repr = set(range(1, len(symbols) + 1))
clauses_int_repr = to_int_repr(clauses, symbols)
result = dpll_int_repr(clauses_int_repr, symbols_int_repr, {})
if not result:
return result
output = {}
for key in result:
output.update({symbols[key - 1]: result[key]})
return output
def dpll(clauses, symbols, model):
"""
Compute satisfiability in a partial model.
Clauses is an array of conjuncts.
>>> from sympy.abc import A, B, D
>>> from sympy.logic.algorithms.dpll import dpll
>>> dpll([A, B, D], [A, B], {D: False})
False
"""
# compute DP kernel
P, value = find_unit_clause(clauses, model)
while P:
model.update({P: value})
symbols.remove(P)
if not value:
P = ~P
clauses = unit_propagate(clauses, P)
P, value = find_unit_clause(clauses, model)
P, value = find_pure_symbol(symbols, clauses)
while P:
model.update({P: value})
symbols.remove(P)
if not value:
P = ~P
clauses = unit_propagate(clauses, P)
P, value = find_pure_symbol(symbols, clauses)
# end DP kernel
unknown_clauses = []
for c in clauses:
val = pl_true(c, model)
if val is False:
return False
if val is not True:
unknown_clauses.append(c)
if not unknown_clauses:
return model
if not clauses:
return model
P = symbols.pop()
model_copy = model.copy()
model.update({P: True})
model_copy.update({P: False})
symbols_copy = symbols[:]
return (dpll(unit_propagate(unknown_clauses, P), symbols, model) or
dpll(unit_propagate(unknown_clauses, Not(P)), symbols_copy, model_copy))
def dpll_int_repr(clauses, symbols, model):
"""
Compute satisfiability in a partial model.
Arguments are expected to be in integer representation
>>> from sympy.logic.algorithms.dpll import dpll_int_repr
>>> dpll_int_repr([{1}, {2}, {3}], {1, 2}, {3: False})
False
"""
# compute DP kernel
P, value = find_unit_clause_int_repr(clauses, model)
while P:
model.update({P: value})
symbols.remove(P)
if not value:
P = -P
clauses = unit_propagate_int_repr(clauses, P)
P, value = find_unit_clause_int_repr(clauses, model)
P, value = find_pure_symbol_int_repr(symbols, clauses)
while P:
model.update({P: value})
symbols.remove(P)
if not value:
P = -P
clauses = unit_propagate_int_repr(clauses, P)
P, value = find_pure_symbol_int_repr(symbols, clauses)
# end DP kernel
unknown_clauses = []
for c in clauses:
val = pl_true_int_repr(c, model)
if val is False:
return False
if val is not True:
unknown_clauses.append(c)
if not unknown_clauses:
return model
P = symbols.pop()
model_copy = model.copy()
model.update({P: True})
model_copy.update({P: False})
symbols_copy = symbols.copy()
return (dpll_int_repr(unit_propagate_int_repr(unknown_clauses, P), symbols, model) or
dpll_int_repr(unit_propagate_int_repr(unknown_clauses, -P), symbols_copy, model_copy))
### helper methods for DPLL
def pl_true_int_repr(clause, model={}):
"""
Lightweight version of pl_true.
Argument clause represents the set of args of an Or clause. This is used
inside dpll_int_repr, it is not meant to be used directly.
>>> from sympy.logic.algorithms.dpll import pl_true_int_repr
>>> pl_true_int_repr({1, 2}, {1: False})
>>> pl_true_int_repr({1, 2}, {1: False, 2: False})
False
"""
result = False
for lit in clause:
if lit < 0:
p = model.get(-lit)
if p is not None:
p = not p
else:
p = model.get(lit)
if p is True:
return True
elif p is None:
result = None
return result
def unit_propagate(clauses, symbol):
"""
Returns an equivalent set of clauses
If a set of clauses contains the unit clause l, the other clauses are
simplified by the application of the two following rules:
1. every clause containing l is removed
2. in every clause that contains ~l this literal is deleted
Arguments are expected to be in CNF.
>>> from sympy.abc import A, B, D
>>> from sympy.logic.algorithms.dpll import unit_propagate
>>> unit_propagate([A | B, D | ~B, B], B)
[D, B]
"""
output = []
for c in clauses:
if c.func != Or:
output.append(c)
continue
for arg in c.args:
if arg == ~symbol:
output.append(Or(*[x for x in c.args if x != ~symbol]))
break
if arg == symbol:
break
else:
output.append(c)
return output
def unit_propagate_int_repr(clauses, s):
"""
Same as unit_propagate, but arguments are expected to be in integer
representation
>>> from sympy.logic.algorithms.dpll import unit_propagate_int_repr
>>> unit_propagate_int_repr([{1, 2}, {3, -2}, {2}], 2)
[{3}]
"""
negated = {-s}
return [clause - negated for clause in clauses if s not in clause]
def find_pure_symbol(symbols, unknown_clauses):
"""
Find a symbol and its value if it appears only as a positive literal
(or only as a negative) in clauses.
>>> from sympy.abc import A, B, D
>>> from sympy.logic.algorithms.dpll import find_pure_symbol
>>> find_pure_symbol([A, B, D], [A|~B,~B|~D,D|A])
(A, True)
"""
for sym in symbols:
found_pos, found_neg = False, False
for c in unknown_clauses:
if not found_pos and sym in disjuncts(c):
found_pos = True
if not found_neg and Not(sym) in disjuncts(c):
found_neg = True
if found_pos != found_neg:
return sym, found_pos
return None, None
def find_pure_symbol_int_repr(symbols, unknown_clauses):
"""
Same as find_pure_symbol, but arguments are expected
to be in integer representation
>>> from sympy.logic.algorithms.dpll import find_pure_symbol_int_repr
>>> find_pure_symbol_int_repr({1,2,3},
... [{1, -2}, {-2, -3}, {3, 1}])
(1, True)
"""
all_symbols = set().union(*unknown_clauses)
found_pos = all_symbols.intersection(symbols)
found_neg = all_symbols.intersection([-s for s in symbols])
for p in found_pos:
if -p not in found_neg:
return p, True
for p in found_neg:
if -p not in found_pos:
return -p, False
return None, None
def find_unit_clause(clauses, model):
"""
A unit clause has only 1 variable that is not bound in the model.
>>> from sympy.abc import A, B, D
>>> from sympy.logic.algorithms.dpll import find_unit_clause
>>> find_unit_clause([A | B | D, B | ~D, A | ~B], {A:True})
(B, False)
"""
for clause in clauses:
num_not_in_model = 0
for literal in disjuncts(clause):
sym = literal_symbol(literal)
if sym not in model:
num_not_in_model += 1
P, value = sym, not isinstance(literal, Not)
if num_not_in_model == 1:
return P, value
return None, None
def find_unit_clause_int_repr(clauses, model):
"""
Same as find_unit_clause, but arguments are expected to be in
integer representation.
>>> from sympy.logic.algorithms.dpll import find_unit_clause_int_repr
>>> find_unit_clause_int_repr([{1, 2, 3},
... {2, -3}, {1, -2}], {1: True})
(2, False)
"""
bound = set(model) | {-sym for sym in model}
for clause in clauses:
unbound = clause - bound
if len(unbound) == 1:
p = unbound.pop()
if p < 0:
return -p, False
else:
return p, True
return None, None
PK ]ZZZ��
S
S sympy/logic/algorithms/dpll2.py"""Implementation of DPLL algorithm
Features:
- Clause learning
- Watch literal scheme
- VSIDS heuristic
References:
- https://en.wikipedia.org/wiki/DPLL_algorithm
"""
from collections import defaultdict
from heapq import heappush, heappop
from sympy.core.sorting import ordered
from sympy.assumptions.cnf import EncodedCNF
from sympy.logic.algorithms.lra_theory import LRASolver
def dpll_satisfiable(expr, all_models=False, use_lra_theory=False):
"""
Check satisfiability of a propositional sentence.
It returns a model rather than True when it succeeds.
Returns a generator of all models if all_models is True.
Examples
========
>>> from sympy.abc import A, B
>>> from sympy.logic.algorithms.dpll2 import dpll_satisfiable
>>> dpll_satisfiable(A & ~B)
{A: True, B: False}
>>> dpll_satisfiable(A & ~A)
False
"""
if not isinstance(expr, EncodedCNF):
exprs = EncodedCNF()
exprs.add_prop(expr)
expr = exprs
# Return UNSAT when False (encoded as 0) is present in the CNF
if {0} in expr.data:
if all_models:
return (f for f in [False])
return False
if use_lra_theory:
lra, immediate_conflicts = LRASolver.from_encoded_cnf(expr)
else:
lra = None
immediate_conflicts = []
solver = SATSolver(expr.data + immediate_conflicts, expr.variables, set(), expr.symbols, lra_theory=lra)
models = solver._find_model()
if all_models:
return _all_models(models)
try:
return next(models)
except StopIteration:
return False
# Uncomment to confirm the solution is valid (hitting set for the clauses)
#else:
#for cls in clauses_int_repr:
#assert solver.var_settings.intersection(cls)
def _all_models(models):
satisfiable = False
try:
while True:
yield next(models)
satisfiable = True
except StopIteration:
if not satisfiable:
yield False
class SATSolver:
"""
Class for representing a SAT solver capable of
finding a model to a boolean theory in conjunctive
normal form.
"""
def __init__(self, clauses, variables, var_settings, symbols=None,
heuristic='vsids', clause_learning='none', INTERVAL=500,
lra_theory = None):
self.var_settings = var_settings
self.heuristic = heuristic
self.is_unsatisfied = False
self._unit_prop_queue = []
self.update_functions = []
self.INTERVAL = INTERVAL
if symbols is None:
self.symbols = list(ordered(variables))
else:
self.symbols = symbols
self._initialize_variables(variables)
self._initialize_clauses(clauses)
if 'vsids' == heuristic:
self._vsids_init()
self.heur_calculate = self._vsids_calculate
self.heur_lit_assigned = self._vsids_lit_assigned
self.heur_lit_unset = self._vsids_lit_unset
self.heur_clause_added = self._vsids_clause_added
# Note: Uncomment this if/when clause learning is enabled
#self.update_functions.append(self._vsids_decay)
else:
raise NotImplementedError
if 'simple' == clause_learning:
self.add_learned_clause = self._simple_add_learned_clause
self.compute_conflict = self._simple_compute_conflict
self.update_functions.append(self._simple_clean_clauses)
elif 'none' == clause_learning:
self.add_learned_clause = lambda x: None
self.compute_conflict = lambda: None
else:
raise NotImplementedError
# Create the base level
self.levels = [Level(0)]
self._current_level.varsettings = var_settings
# Keep stats
self.num_decisions = 0
self.num_learned_clauses = 0
self.original_num_clauses = len(self.clauses)
self.lra = lra_theory
def _initialize_variables(self, variables):
"""Set up the variable data structures needed."""
self.sentinels = defaultdict(set)
self.occurrence_count = defaultdict(int)
self.variable_set = [False] * (len(variables) + 1)
def _initialize_clauses(self, clauses):
"""Set up the clause data structures needed.
For each clause, the following changes are made:
- Unit clauses are queued for propagation right away.
- Non-unit clauses have their first and last literals set as sentinels.
- The number of clauses a literal appears in is computed.
"""
self.clauses = [list(clause) for clause in clauses]
for i, clause in enumerate(self.clauses):
# Handle the unit clauses
if 1 == len(clause):
self._unit_prop_queue.append(clause[0])
continue
self.sentinels[clause[0]].add(i)
self.sentinels[clause[-1]].add(i)
for lit in clause:
self.occurrence_count[lit] += 1
def _find_model(self):
"""
Main DPLL loop. Returns a generator of models.
Variables are chosen successively, and assigned to be either
True or False. If a solution is not found with this setting,
the opposite is chosen and the search continues. The solver
halts when every variable has a setting.
Examples
========
>>> from sympy.logic.algorithms.dpll2 import SATSolver
>>> l = SATSolver([{2, -3}, {1}, {3, -3}, {2, -2},
... {3, -2}], {1, 2, 3}, set())
>>> list(l._find_model())
[{1: True, 2: False, 3: False}, {1: True, 2: True, 3: True}]
>>> from sympy.abc import A, B, C
>>> l = SATSolver([{2, -3}, {1}, {3, -3}, {2, -2},
... {3, -2}], {1, 2, 3}, set(), [A, B, C])
>>> list(l._find_model())
[{A: True, B: False, C: False}, {A: True, B: True, C: True}]
"""
# We use this variable to keep track of if we should flip a
# variable setting in successive rounds
flip_var = False
# Check if unit prop says the theory is unsat right off the bat
self._simplify()
if self.is_unsatisfied:
return
# While the theory still has clauses remaining
while True:
# Perform cleanup / fixup at regular intervals
if self.num_decisions % self.INTERVAL == 0:
for func in self.update_functions:
func()
if flip_var:
# We have just backtracked and we are trying to opposite literal
flip_var = False
lit = self._current_level.decision
else:
# Pick a literal to set
lit = self.heur_calculate()
self.num_decisions += 1
# Stopping condition for a satisfying theory
if 0 == lit:
# check if assignment satisfies lra theory
if self.lra:
for enc_var in self.var_settings:
res = self.lra.assert_lit(enc_var)
if res is not None:
break
res = self.lra.check()
self.lra.reset_bounds()
else:
res = None
if res is None or res[0]:
yield {self.symbols[abs(lit) - 1]:
lit > 0 for lit in self.var_settings}
else:
self._simple_add_learned_clause(res[1])
while self._current_level.flipped:
self._undo()
if len(self.levels) == 1:
return
flip_lit = -self._current_level.decision
self._undo()
self.levels.append(Level(flip_lit, flipped=True))
flip_var = True
continue
# Start the new decision level
self.levels.append(Level(lit))
# Assign the literal, updating the clauses it satisfies
self._assign_literal(lit)
# _simplify the theory
self._simplify()
# Check if we've made the theory unsat
if self.is_unsatisfied:
self.is_unsatisfied = False
# We unroll all of the decisions until we can flip a literal
while self._current_level.flipped:
self._undo()
# If we've unrolled all the way, the theory is unsat
if 1 == len(self.levels):
return
# Detect and add a learned clause
self.add_learned_clause(self.compute_conflict())
# Try the opposite setting of the most recent decision
flip_lit = -self._current_level.decision
self._undo()
self.levels.append(Level(flip_lit, flipped=True))
flip_var = True
########################
# Helper Methods #
########################
@property
def _current_level(self):
"""The current decision level data structure
Examples
========
>>> from sympy.logic.algorithms.dpll2 import SATSolver
>>> l = SATSolver([{1}, {2}], {1, 2}, set())
>>> next(l._find_model())
{1: True, 2: True}
>>> l._current_level.decision
0
>>> l._current_level.flipped
False
>>> l._current_level.var_settings
{1, 2}
"""
return self.levels[-1]
def _clause_sat(self, cls):
"""Check if a clause is satisfied by the current variable setting.
Examples
========
>>> from sympy.logic.algorithms.dpll2 import SATSolver
>>> l = SATSolver([{1}, {-1}], {1}, set())
>>> try:
... next(l._find_model())
... except StopIteration:
... pass
>>> l._clause_sat(0)
False
>>> l._clause_sat(1)
True
"""
for lit in self.clauses[cls]:
if lit in self.var_settings:
return True
return False
def _is_sentinel(self, lit, cls):
"""Check if a literal is a sentinel of a given clause.
Examples
========
>>> from sympy.logic.algorithms.dpll2 import SATSolver
>>> l = SATSolver([{2, -3}, {1}, {3, -3}, {2, -2},
... {3, -2}], {1, 2, 3}, set())
>>> next(l._find_model())
{1: True, 2: False, 3: False}
>>> l._is_sentinel(2, 3)
True
>>> l._is_sentinel(-3, 1)
False
"""
return cls in self.sentinels[lit]
def _assign_literal(self, lit):
"""Make a literal assignment.
The literal assignment must be recorded as part of the current
decision level. Additionally, if the literal is marked as a
sentinel of any clause, then a new sentinel must be chosen. If
this is not possible, then unit propagation is triggered and
another literal is added to the queue to be set in the future.
Examples
========
>>> from sympy.logic.algorithms.dpll2 import SATSolver
>>> l = SATSolver([{2, -3}, {1}, {3, -3}, {2, -2},
... {3, -2}], {1, 2, 3}, set())
>>> next(l._find_model())
{1: True, 2: False, 3: False}
>>> l.var_settings
{-3, -2, 1}
>>> l = SATSolver([{2, -3}, {1}, {3, -3}, {2, -2},
... {3, -2}], {1, 2, 3}, set())
>>> l._assign_literal(-1)
>>> try:
... next(l._find_model())
... except StopIteration:
... pass
>>> l.var_settings
{-1}
"""
self.var_settings.add(lit)
self._current_level.var_settings.add(lit)
self.variable_set[abs(lit)] = True
self.heur_lit_assigned(lit)
sentinel_list = list(self.sentinels[-lit])
for cls in sentinel_list:
if not self._clause_sat(cls):
other_sentinel = None
for newlit in self.clauses[cls]:
if newlit != -lit:
if self._is_sentinel(newlit, cls):
other_sentinel = newlit
elif not self.variable_set[abs(newlit)]:
self.sentinels[-lit].remove(cls)
self.sentinels[newlit].add(cls)
other_sentinel = None
break
# Check if no sentinel update exists
if other_sentinel:
self._unit_prop_queue.append(other_sentinel)
def _undo(self):
"""
_undo the changes of the most recent decision level.
Examples
========
>>> from sympy.logic.algorithms.dpll2 import SATSolver
>>> l = SATSolver([{2, -3}, {1}, {3, -3}, {2, -2},
... {3, -2}], {1, 2, 3}, set())
>>> next(l._find_model())
{1: True, 2: False, 3: False}
>>> level = l._current_level
>>> level.decision, level.var_settings, level.flipped
(-3, {-3, -2}, False)
>>> l._undo()
>>> level = l._current_level
>>> level.decision, level.var_settings, level.flipped
(0, {1}, False)
"""
# Undo the variable settings
for lit in self._current_level.var_settings:
self.var_settings.remove(lit)
self.heur_lit_unset(lit)
self.variable_set[abs(lit)] = False
# Pop the level off the stack
self.levels.pop()
#########################
# Propagation #
#########################
"""
Propagation methods should attempt to soundly simplify the boolean
theory, and return True if any simplification occurred and False
otherwise.
"""
def _simplify(self):
"""Iterate over the various forms of propagation to simplify the theory.
Examples
========
>>> from sympy.logic.algorithms.dpll2 import SATSolver
>>> l = SATSolver([{2, -3}, {1}, {3, -3}, {2, -2},
... {3, -2}], {1, 2, 3}, set())
>>> l.variable_set
[False, False, False, False]
>>> l.sentinels
{-3: {0, 2}, -2: {3, 4}, 2: {0, 3}, 3: {2, 4}}
>>> l._simplify()
>>> l.variable_set
[False, True, False, False]
>>> l.sentinels
{-3: {0, 2}, -2: {3, 4}, -1: set(), 2: {0, 3},
...3: {2, 4}}
"""
changed = True
while changed:
changed = False
changed |= self._unit_prop()
changed |= self._pure_literal()
def _unit_prop(self):
"""Perform unit propagation on the current theory."""
result = len(self._unit_prop_queue) > 0
while self._unit_prop_queue:
next_lit = self._unit_prop_queue.pop()
if -next_lit in self.var_settings:
self.is_unsatisfied = True
self._unit_prop_queue = []
return False
else:
self._assign_literal(next_lit)
return result
def _pure_literal(self):
"""Look for pure literals and assign them when found."""
return False
#########################
# Heuristics #
#########################
def _vsids_init(self):
"""Initialize the data structures needed for the VSIDS heuristic."""
self.lit_heap = []
self.lit_scores = {}
for var in range(1, len(self.variable_set)):
self.lit_scores[var] = float(-self.occurrence_count[var])
self.lit_scores[-var] = float(-self.occurrence_count[-var])
heappush(self.lit_heap, (self.lit_scores[var], var))
heappush(self.lit_heap, (self.lit_scores[-var], -var))
def _vsids_decay(self):
"""Decay the VSIDS scores for every literal.
Examples
========
>>> from sympy.logic.algorithms.dpll2 import SATSolver
>>> l = SATSolver([{2, -3}, {1}, {3, -3}, {2, -2},
... {3, -2}], {1, 2, 3}, set())
>>> l.lit_scores
{-3: -2.0, -2: -2.0, -1: 0.0, 1: 0.0, 2: -2.0, 3: -2.0}
>>> l._vsids_decay()
>>> l.lit_scores
{-3: -1.0, -2: -1.0, -1: 0.0, 1: 0.0, 2: -1.0, 3: -1.0}
"""
# We divide every literal score by 2 for a decay factor
# Note: This doesn't change the heap property
for lit in self.lit_scores.keys():
self.lit_scores[lit] /= 2.0
def _vsids_calculate(self):
"""
VSIDS Heuristic Calculation
Examples
========
>>> from sympy.logic.algorithms.dpll2 import SATSolver
>>> l = SATSolver([{2, -3}, {1}, {3, -3}, {2, -2},
... {3, -2}], {1, 2, 3}, set())
>>> l.lit_heap
[(-2.0, -3), (-2.0, 2), (-2.0, -2), (0.0, 1), (-2.0, 3), (0.0, -1)]
>>> l._vsids_calculate()
-3
>>> l.lit_heap
[(-2.0, -2), (-2.0, 2), (0.0, -1), (0.0, 1), (-2.0, 3)]
"""
if len(self.lit_heap) == 0:
return 0
# Clean out the front of the heap as long the variables are set
while self.variable_set[abs(self.lit_heap[0][1])]:
heappop(self.lit_heap)
if len(self.lit_heap) == 0:
return 0
return heappop(self.lit_heap)[1]
def _vsids_lit_assigned(self, lit):
"""Handle the assignment of a literal for the VSIDS heuristic."""
pass
def _vsids_lit_unset(self, lit):
"""Handle the unsetting of a literal for the VSIDS heuristic.
Examples
========
>>> from sympy.logic.algorithms.dpll2 import SATSolver
>>> l = SATSolver([{2, -3}, {1}, {3, -3}, {2, -2},
... {3, -2}], {1, 2, 3}, set())
>>> l.lit_heap
[(-2.0, -3), (-2.0, 2), (-2.0, -2), (0.0, 1), (-2.0, 3), (0.0, -1)]
>>> l._vsids_lit_unset(2)
>>> l.lit_heap
[(-2.0, -3), (-2.0, -2), (-2.0, -2), (-2.0, 2), (-2.0, 3), (0.0, -1),
...(-2.0, 2), (0.0, 1)]
"""
var = abs(lit)
heappush(self.lit_heap, (self.lit_scores[var], var))
heappush(self.lit_heap, (self.lit_scores[-var], -var))
def _vsids_clause_added(self, cls):
"""Handle the addition of a new clause for the VSIDS heuristic.
Examples
========
>>> from sympy.logic.algorithms.dpll2 import SATSolver
>>> l = SATSolver([{2, -3}, {1}, {3, -3}, {2, -2},
... {3, -2}], {1, 2, 3}, set())
>>> l.num_learned_clauses
0
>>> l.lit_scores
{-3: -2.0, -2: -2.0, -1: 0.0, 1: 0.0, 2: -2.0, 3: -2.0}
>>> l._vsids_clause_added({2, -3})
>>> l.num_learned_clauses
1
>>> l.lit_scores
{-3: -1.0, -2: -2.0, -1: 0.0, 1: 0.0, 2: -1.0, 3: -2.0}
"""
self.num_learned_clauses += 1
for lit in cls:
self.lit_scores[lit] += 1
########################
# Clause Learning #
########################
def _simple_add_learned_clause(self, cls):
"""Add a new clause to the theory.
Examples
========
>>> from sympy.logic.algorithms.dpll2 import SATSolver
>>> l = SATSolver([{2, -3}, {1}, {3, -3}, {2, -2},
... {3, -2}], {1, 2, 3}, set())
>>> l.num_learned_clauses
0
>>> l.clauses
[[2, -3], [1], [3, -3], [2, -2], [3, -2]]
>>> l.sentinels
{-3: {0, 2}, -2: {3, 4}, 2: {0, 3}, 3: {2, 4}}
>>> l._simple_add_learned_clause([3])
>>> l.clauses
[[2, -3], [1], [3, -3], [2, -2], [3, -2], [3]]
>>> l.sentinels
{-3: {0, 2}, -2: {3, 4}, 2: {0, 3}, 3: {2, 4, 5}}
"""
cls_num = len(self.clauses)
self.clauses.append(cls)
for lit in cls:
self.occurrence_count[lit] += 1
self.sentinels[cls[0]].add(cls_num)
self.sentinels[cls[-1]].add(cls_num)
self.heur_clause_added(cls)
def _simple_compute_conflict(self):
""" Build a clause representing the fact that at least one decision made
so far is wrong.
Examples
========
>>> from sympy.logic.algorithms.dpll2 import SATSolver
>>> l = SATSolver([{2, -3}, {1}, {3, -3}, {2, -2},
... {3, -2}], {1, 2, 3}, set())
>>> next(l._find_model())
{1: True, 2: False, 3: False}
>>> l._simple_compute_conflict()
[3]
"""
return [-(level.decision) for level in self.levels[1:]]
def _simple_clean_clauses(self):
"""Clean up learned clauses."""
pass
class Level:
"""
Represents a single level in the DPLL algorithm, and contains
enough information for a sound backtracking procedure.
"""
def __init__(self, decision, flipped=False):
self.decision = decision
self.var_settings = set()
self.flipped = flipped
PK ]ZZZ�i�I| I| $ sympy/logic/algorithms/lra_theory.py"""Implements "A Fast Linear-Arithmetic Solver for DPLL(T)"
The LRASolver class defined in this file can be used
in conjunction with a SAT solver to check the
satisfiability of formulas involving inequalities.
Here's an example of how that would work:
Suppose you want to check the satisfiability of
the following formula:
>>> from sympy.core.relational import Eq
>>> from sympy.abc import x, y
>>> f = ((x > 0) | (x < 0)) & (Eq(x, 0) | Eq(y, 1)) & (~Eq(y, 1) | Eq(1, 2))
First a preprocessing step should be done on f. During preprocessing,
f should be checked for any predicates such as `Q.prime` that can't be
handled. Also unequality like `~Eq(y, 1)` should be split.
I should mention that the paper says to split both equalities and
unequality, but this implementation only requires that unequality
be split.
>>> f = ((x > 0) | (x < 0)) & (Eq(x, 0) | Eq(y, 1)) & ((y < 1) | (y > 1) | Eq(1, 2))
Then an LRASolver instance needs to be initialized with this formula.
>>> from sympy.assumptions.cnf import CNF, EncodedCNF
>>> from sympy.assumptions.ask import Q
>>> from sympy.logic.algorithms.lra_theory import LRASolver
>>> cnf = CNF.from_prop(f)
>>> enc = EncodedCNF()
>>> enc.add_from_cnf(cnf)
>>> lra, conflicts = LRASolver.from_encoded_cnf(enc)
Any immediate one-lital conflicts clauses will be detected here.
In this example, `~Eq(1, 2)` is one such conflict clause. We'll
want to add it to `f` so that the SAT solver is forced to
assign Eq(1, 2) to False.
>>> f = f & ~Eq(1, 2)
Now that the one-literal conflict clauses have been added
and an lra object has been initialized, we can pass `f`
to a SAT solver. The SAT solver will give us a satisfying
assignment such as:
(1 = 2): False
(y = 1): True
(y < 1): True
(y > 1): True
(x = 0): True
(x < 0): True
(x > 0): True
Next you would pass this assignment to the LRASolver
which will be able to determine that this particular
assignment is satisfiable or not.
Note that since EncodedCNF is inherently non-deterministic,
the int each predicate is encoded as is not consistent. As a
result, the code bellow likely does not reflect the assignment
given above.
>>> lra.assert_lit(-1) #doctest: +SKIP
>>> lra.assert_lit(2) #doctest: +SKIP
>>> lra.assert_lit(3) #doctest: +SKIP
>>> lra.assert_lit(4) #doctest: +SKIP
>>> lra.assert_lit(5) #doctest: +SKIP
>>> lra.assert_lit(6) #doctest: +SKIP
>>> lra.assert_lit(7) #doctest: +SKIP
>>> is_sat, conflict_or_assignment = lra.check()
As the particular assignment suggested is not satisfiable,
the LRASolver will return unsat and a conflict clause when
given that assignment. The conflict clause will always be
minimal, but there can be multiple minimal conflict clauses.
One possible conflict clause could be `~(x < 0) | ~(x > 0)`.
We would then add whatever conflict clause is given to
`f` to prevent the SAT solver from coming up with an
assignment with the same conflicting literals. In this case,
the conflict clause `~(x < 0) | ~(x > 0)` would prevent
any assignment where both (x < 0) and (x > 0) were both
true.
The SAT solver would then find another assignment
and we would check that assignment with the LRASolver
and so on. Eventually either a satisfying assignment
that the SAT solver and LRASolver agreed on would be found
or enough conflict clauses would be added so that the
boolean formula was unsatisfiable.
This implementation is based on [1]_, which includes a
detailed explanation of the algorithm and pseudocode
for the most important functions.
[1]_ also explains how backtracking and theory propagation
could be implemented to speed up the current implementation,
but these are not currently implemented.
TODO:
- Handle non-rational real numbers
- Handle positive and negative infinity
- Implement backtracking and theory proposition
- Simplify matrix by removing unused variables using Gaussian elimination
References
==========
.. [1] Dutertre, B., de Moura, L.:
A Fast Linear-Arithmetic Solver for DPLL(T)
https://link.springer.com/chapter/10.1007/11817963_11
"""
from sympy.solvers.solveset import linear_eq_to_matrix
from sympy.matrices.dense import eye
from sympy.assumptions import Predicate
from sympy.assumptions.assume import AppliedPredicate
from sympy.assumptions.ask import Q
from sympy.core import Dummy
from sympy.core.mul import Mul
from sympy.core.add import Add
from sympy.core.relational import Eq, Ne
from sympy.core.sympify import sympify
from sympy.core.singleton import S
from sympy.core.numbers import Rational, oo
from sympy.matrices.dense import Matrix
class UnhandledInput(Exception):
"""
Raised while creating an LRASolver if non-linearity
or non-rational numbers are present.
"""
# predicates that LRASolver understands and makes use of
ALLOWED_PRED = {Q.eq, Q.gt, Q.lt, Q.le, Q.ge}
# if true ~Q.gt(x, y) implies Q.le(x, y)
HANDLE_NEGATION = True
class LRASolver():
"""
Linear Arithmetic Solver for DPLL(T) implemented with an algorithm based on
the Dual Simplex method. Uses Bland's pivoting rule to avoid cycling.
References
==========
.. [1] Dutertre, B., de Moura, L.:
A Fast Linear-Arithmetic Solver for DPLL(T)
https://link.springer.com/chapter/10.1007/11817963_11
"""
def __init__(self, A, slack_variables, nonslack_variables, enc_to_boundary, s_subs, testing_mode):
"""
Use the "from_encoded_cnf" method to create a new LRASolver.
"""
self.run_checks = testing_mode
self.s_subs = s_subs # used only for test_lra_theory.test_random_problems
if any(not isinstance(a, Rational) for a in A):
raise UnhandledInput("Non-rational numbers are not handled")
if any(not isinstance(b.bound, Rational) for b in enc_to_boundary.values()):
raise UnhandledInput("Non-rational numbers are not handled")
m, n = len(slack_variables), len(slack_variables)+len(nonslack_variables)
if m != 0:
assert A.shape == (m, n)
if self.run_checks:
assert A[:, n-m:] == -eye(m)
self.enc_to_boundary = enc_to_boundary # mapping of int to Boundry objects
self.boundary_to_enc = {value: key for key, value in enc_to_boundary.items()}
self.A = A
self.slack = slack_variables
self.nonslack = nonslack_variables
self.all_var = nonslack_variables + slack_variables
self.slack_set = set(slack_variables)
self.is_sat = True # While True, all constraints asserted so far are satisfiable
self.result = None # always one of: (True, assignment), (False, conflict clause), None
@staticmethod
def from_encoded_cnf(encoded_cnf, testing_mode=False):
"""
Creates an LRASolver from an EncodedCNF object
and a list of conflict clauses for propositions
that can be simplified to True or False.
Parameters
==========
encoded_cnf : EncodedCNF
testing_mode : bool
Setting testing_mode to True enables some slow assert statements
and sorting to reduce nonterministic behavior.
Returns
=======
(lra, conflicts)
lra : LRASolver
conflicts : list
Contains a one-literal conflict clause for each proposition
that can be simplified to True or False.
Example
=======
>>> from sympy.core.relational import Eq
>>> from sympy.assumptions.cnf import CNF, EncodedCNF
>>> from sympy.assumptions.ask import Q
>>> from sympy.logic.algorithms.lra_theory import LRASolver
>>> from sympy.abc import x, y, z
>>> phi = (x >= 0) & ((x + y <= 2) | (x + 2 * y - z >= 6))
>>> phi = phi & (Eq(x + y, 2) | (x + 2 * y - z > 4))
>>> phi = phi & Q.gt(2, 1)
>>> cnf = CNF.from_prop(phi)
>>> enc = EncodedCNF()
>>> enc.from_cnf(cnf)
>>> lra, conflicts = LRASolver.from_encoded_cnf(enc, testing_mode=True)
>>> lra #doctest: +SKIP
<sympy.logic.algorithms.lra_theory.LRASolver object at 0x7fdcb0e15b70>
>>> conflicts #doctest: +SKIP
[[4]]
"""
# This function has three main jobs:
# - raise errors if the input formula is not handled
# - preprocesses the formula into a matirx and single variable constraints
# - create one-literal conflict clauses from predicates that are always True
# or always False such as Q.gt(3, 2)
#
# See the preprocessing section of "A Fast Linear-Arithmetic Solver for DPLL(T)"
# for an explanation of how the formula is converted into a matrix
# and a set of single variable constraints.
encoding = {} # maps int to boundary
A = []
basic = []
s_count = 0
s_subs = {}
nonbasic = []
if testing_mode:
# sort to reduce nondeterminism
encoded_cnf_items = sorted(encoded_cnf.encoding.items(), key=lambda x: str(x))
else:
encoded_cnf_items = encoded_cnf.encoding.items()
empty_var = Dummy()
var_to_lra_var = {}
conflicts = []
for prop, enc in encoded_cnf_items:
if isinstance(prop, Predicate):
prop = prop(empty_var)
if not isinstance(prop, AppliedPredicate):
if prop == True:
conflicts.append([enc])
continue
if prop == False:
conflicts.append([-enc])
continue
raise ValueError(f"Unhandled Predicate: {prop}")
assert prop.function in ALLOWED_PRED
if prop.lhs == S.NaN or prop.rhs == S.NaN:
raise ValueError(f"{prop} contains nan")
if prop.lhs.is_imaginary or prop.rhs.is_imaginary:
raise UnhandledInput(f"{prop} contains an imaginary component")
if prop.lhs == oo or prop.rhs == oo:
raise UnhandledInput(f"{prop} contains infinity")
prop = _eval_binrel(prop) # simplify variable-less quantities to True / False if possible
if prop == True:
conflicts.append([enc])
continue
elif prop == False:
conflicts.append([-enc])
continue
elif prop is None:
raise UnhandledInput(f"{prop} could not be simplified")
expr = prop.lhs - prop.rhs
if prop.function in [Q.ge, Q.gt]:
expr = -expr
# expr should be less than (or equal to) 0
# otherwise prop is False
if prop.function in [Q.le, Q.ge]:
bool = (expr <= 0)
elif prop.function in [Q.lt, Q.gt]:
bool = (expr < 0)
else:
assert prop.function == Q.eq
bool = Eq(expr, 0)
if bool == True:
conflicts.append([enc])
continue
elif bool == False:
conflicts.append([-enc])
continue
vars, const = _sep_const_terms(expr) # example: (2x + 3y + 2) --> (2x + 3y), (2)
vars, var_coeff = _sep_const_coeff(vars) # examples: (2x) --> (x, 2); (2x + 3y) --> (2x + 3y), (1)
const = const / var_coeff
terms = _list_terms(vars) # example: (2x + 3y) --> [2x, 3y]
for term in terms:
term, _ = _sep_const_coeff(term)
assert len(term.free_symbols) > 0
if term not in var_to_lra_var:
var_to_lra_var[term] = LRAVariable(term)
nonbasic.append(term)
if len(terms) > 1:
if vars not in s_subs:
s_count += 1
d = Dummy(f"s{s_count}")
var_to_lra_var[d] = LRAVariable(d)
basic.append(d)
s_subs[vars] = d
A.append(vars - d)
var = s_subs[vars]
else:
var = terms[0]
assert var_coeff != 0
equality = prop.function == Q.eq
upper = var_coeff > 0 if not equality else None
strict = prop.function in [Q.gt, Q.lt]
b = Boundary(var_to_lra_var[var], -const, upper, equality, strict)
encoding[enc] = b
fs = [v.free_symbols for v in nonbasic + basic]
assert all(len(syms) > 0 for syms in fs)
fs_count = sum(len(syms) for syms in fs)
if len(fs) > 0 and len(set.union(*fs)) < fs_count:
raise UnhandledInput("Nonlinearity is not handled")
A, _ = linear_eq_to_matrix(A, nonbasic + basic)
nonbasic = [var_to_lra_var[nb] for nb in nonbasic]
basic = [var_to_lra_var[b] for b in basic]
for idx, var in enumerate(nonbasic + basic):
var.col_idx = idx
return LRASolver(A, basic, nonbasic, encoding, s_subs, testing_mode), conflicts
def reset_bounds(self):
"""
Resets the state of the LRASolver to before
anything was asserted.
"""
self.result = None
for var in self.all_var:
var.lower = LRARational(-float("inf"), 0)
var.lower_from_eq = False
var.lower_from_neg = False
var.upper = LRARational(float("inf"), 0)
var.upper_from_eq= False
var.lower_from_neg = False
var.assign = LRARational(0, 0)
def assert_lit(self, enc_constraint):
"""
Assert a literal representing a constraint
and update the internal state accordingly.
Note that due to peculiarities of this implementation
asserting ~(x > 0) will assert (x <= 0) but asserting
~Eq(x, 0) will not do anything.
Parameters
==========
enc_constraint : int
A mapping of encodings to constraints
can be found in `self.enc_to_boundary`.
Returns
=======
None or (False, explanation)
explanation : set of ints
A conflict clause that "explains" why
the literals asserted so far are unsatisfiable.
"""
if abs(enc_constraint) not in self.enc_to_boundary:
return None
if not HANDLE_NEGATION and enc_constraint < 0:
return None
boundary = self.enc_to_boundary[abs(enc_constraint)]
sym, c, negated = boundary.var, boundary.bound, enc_constraint < 0
if boundary.equality and negated:
return None # negated equality is not handled and should only appear in conflict clauses
upper = boundary.upper != negated
if boundary.strict != negated:
delta = -1 if upper else 1
c = LRARational(c, delta)
else:
c = LRARational(c, 0)
if boundary.equality:
res1 = self._assert_lower(sym, c, from_equality=True, from_neg=negated)
if res1 and res1[0] == False:
res = res1
else:
res2 = self._assert_upper(sym, c, from_equality=True, from_neg=negated)
res = res2
elif upper:
res = self._assert_upper(sym, c, from_neg=negated)
else:
res = self._assert_lower(sym, c, from_neg=negated)
if self.is_sat and sym not in self.slack_set:
self.is_sat = res is None
else:
self.is_sat = False
return res
def _assert_upper(self, xi, ci, from_equality=False, from_neg=False):
"""
Adjusts the upper bound on variable xi if the new upper bound is
more limiting. The assignment of variable xi is adjusted to be
within the new bound if needed.
Also calls `self._update` to update the assignment for slack variables
to keep all equalities satisfied.
"""
if self.result:
assert self.result[0] != False
self.result = None
if ci >= xi.upper:
return None
if ci < xi.lower:
assert (xi.lower[1] >= 0) is True
assert (ci[1] <= 0) is True
lit1, neg1 = Boundary.from_lower(xi)
lit2 = Boundary(var=xi, const=ci[0], strict=ci[1] != 0, upper=True, equality=from_equality)
if from_neg:
lit2 = lit2.get_negated()
neg2 = -1 if from_neg else 1
conflict = [-neg1*self.boundary_to_enc[lit1], -neg2*self.boundary_to_enc[lit2]]
self.result = False, conflict
return self.result
xi.upper = ci
xi.upper_from_eq = from_equality
xi.upper_from_neg = from_neg
if xi in self.nonslack and xi.assign > ci:
self._update(xi, ci)
if self.run_checks and all(v.assign[0] != float("inf") and v.assign[0] != -float("inf")
for v in self.all_var):
M = self.A
X = Matrix([v.assign[0] for v in self.all_var])
assert all(abs(val) < 10 ** (-10) for val in M * X)
return None
def _assert_lower(self, xi, ci, from_equality=False, from_neg=False):
"""
Adjusts the lower bound on variable xi if the new lower bound is
more limiting. The assignment of variable xi is adjusted to be
within the new bound if needed.
Also calls `self._update` to update the assignment for slack variables
to keep all equalities satisfied.
"""
if self.result:
assert self.result[0] != False
self.result = None
if ci <= xi.lower:
return None
if ci > xi.upper:
assert (xi.upper[1] <= 0) is True
assert (ci[1] >= 0) is True
lit1, neg1 = Boundary.from_upper(xi)
lit2 = Boundary(var=xi, const=ci[0], strict=ci[1] != 0, upper=False, equality=from_equality)
if from_neg:
lit2 = lit2.get_negated()
neg2 = -1 if from_neg else 1
conflict = [-neg1*self.boundary_to_enc[lit1],-neg2*self.boundary_to_enc[lit2]]
self.result = False, conflict
return self.result
xi.lower = ci
xi.lower_from_eq = from_equality
xi.lower_from_neg = from_neg
if xi in self.nonslack and xi.assign < ci:
self._update(xi, ci)
if self.run_checks and all(v.assign[0] != float("inf") and v.assign[0] != -float("inf")
for v in self.all_var):
M = self.A
X = Matrix([v.assign[0] for v in self.all_var])
assert all(abs(val) < 10 ** (-10) for val in M * X)
return None
def _update(self, xi, v):
"""
Updates all slack variables that have equations that contain
variable xi so that they stay satisfied given xi is equal to v.
"""
i = xi.col_idx
for j, b in enumerate(self.slack):
aji = self.A[j, i]
b.assign = b.assign + (v - xi.assign)*aji
xi.assign = v
def check(self):
"""
Searches for an assignment that satisfies all constraints
or determines that no such assignment exists and gives
a minimal conflict clause that "explains" why the
constraints are unsatisfiable.
Returns
=======
(True, assignment) or (False, explanation)
assignment : dict of LRAVariables to values
Assigned values are tuples that represent a rational number
plus some infinatesimal delta.
explanation : set of ints
"""
if self.is_sat:
return True, {var: var.assign for var in self.all_var}
if self.result:
return self.result
from sympy.matrices.dense import Matrix
M = self.A.copy()
basic = {s: i for i, s in enumerate(self.slack)} # contains the row index associated with each basic variable
nonbasic = set(self.nonslack)
iteration = 0
while True:
iteration += 1
if self.run_checks:
# nonbasic variables must always be within bounds
assert all(((nb.assign >= nb.lower) == True) and ((nb.assign <= nb.upper) == True) for nb in nonbasic)
# assignments for x must always satisfy Ax = 0
# probably have to turn this off when dealing with strict ineq
if all(v.assign[0] != float("inf") and v.assign[0] != -float("inf")
for v in self.all_var):
X = Matrix([v.assign[0] for v in self.all_var])
assert all(abs(val) < 10**(-10) for val in M*X)
# check upper and lower match this format:
# x <= rat + delta iff x < rat
# x >= rat - delta iff x > rat
# this wouldn't make sense:
# x <= rat - delta
# x >= rat + delta
assert all(x.upper[1] <= 0 for x in self.all_var)
assert all(x.lower[1] >= 0 for x in self.all_var)
cand = [b for b in basic if b.assign < b.lower or b.assign > b.upper]
if len(cand) == 0:
return True, {var: var.assign for var in self.all_var}
xi = min(cand, key=lambda v: v.col_idx) # Bland's rule
i = basic[xi]
if xi.assign < xi.lower:
cand = [nb for nb in nonbasic
if (M[i, nb.col_idx] > 0 and nb.assign < nb.upper)
or (M[i, nb.col_idx] < 0 and nb.assign > nb.lower)]
if len(cand) == 0:
N_plus = [nb for nb in nonbasic if M[i, nb.col_idx] > 0]
N_minus = [nb for nb in nonbasic if M[i, nb.col_idx] < 0]
conflict = []
conflict += [Boundary.from_upper(nb) for nb in N_plus]
conflict += [Boundary.from_lower(nb) for nb in N_minus]
conflict.append(Boundary.from_lower(xi))
conflict = [-neg*self.boundary_to_enc[c] for c, neg in conflict]
return False, conflict
xj = min(cand, key=str)
M = self._pivot_and_update(M, basic, nonbasic, xi, xj, xi.lower)
if xi.assign > xi.upper:
cand = [nb for nb in nonbasic
if (M[i, nb.col_idx] < 0 and nb.assign < nb.upper)
or (M[i, nb.col_idx] > 0 and nb.assign > nb.lower)]
if len(cand) == 0:
N_plus = [nb for nb in nonbasic if M[i, nb.col_idx] > 0]
N_minus = [nb for nb in nonbasic if M[i, nb.col_idx] < 0]
conflict = []
conflict += [Boundary.from_upper(nb) for nb in N_minus]
conflict += [Boundary.from_lower(nb) for nb in N_plus]
conflict.append(Boundary.from_upper(xi))
conflict = [-neg*self.boundary_to_enc[c] for c, neg in conflict]
return False, conflict
xj = min(cand, key=lambda v: v.col_idx)
M = self._pivot_and_update(M, basic, nonbasic, xi, xj, xi.upper)
def _pivot_and_update(self, M, basic, nonbasic, xi, xj, v):
"""
Pivots basic variable xi with nonbasic variable xj,
and sets value of xi to v and adjusts the values of all basic variables
to keep equations satisfied.
"""
i, j = basic[xi], xj.col_idx
assert M[i, j] != 0
theta = (v - xi.assign)*(1/M[i, j])
xi.assign = v
xj.assign = xj.assign + theta
for xk in basic:
if xk != xi:
k = basic[xk]
akj = M[k, j]
xk.assign = xk.assign + theta*akj
# pivot
basic[xj] = basic[xi]
del basic[xi]
nonbasic.add(xi)
nonbasic.remove(xj)
return self._pivot(M, i, j)
@staticmethod
def _pivot(M, i, j):
"""
Performs a pivot operation about entry i, j of M by performing
a series of row operations on a copy of M and returing the result.
The original M is left unmodified.
Conceptually, M represents a system of equations and pivoting
can be thought of as rearranging equation i to be in terms of
variable j and then substituting in the rest of the equations
to get rid of other occurances of variable j.
Example
=======
>>> from sympy.matrices.dense import Matrix
>>> from sympy.logic.algorithms.lra_theory import LRASolver
>>> from sympy import var
>>> Matrix(3, 3, var('a:i'))
Matrix([
[a, b, c],
[d, e, f],
[g, h, i]])
This matrix is equivalent to:
0 = a*x + b*y + c*z
0 = d*x + e*y + f*z
0 = g*x + h*y + i*z
>>> LRASolver._pivot(_, 1, 0)
Matrix([
[ 0, -a*e/d + b, -a*f/d + c],
[-1, -e/d, -f/d],
[ 0, h - e*g/d, i - f*g/d]])
We rearrange equation 1 in terms of variable 0 (x)
and substitute to remove x from the other equations.
0 = 0 + (-a*e/d + b)*y + (-a*f/d + c)*z
0 = -x + (-e/d)*y + (-f/d)*z
0 = 0 + (h - e*g/d)*y + (i - f*g/d)*z
"""
_, _, Mij = M[i, :], M[:, j], M[i, j]
if Mij == 0:
raise ZeroDivisionError("Tried to pivot about zero-valued entry.")
A = M.copy()
A[i, :] = -A[i, :]/Mij
for row in range(M.shape[0]):
if row != i:
A[row, :] = A[row, :] + A[row, j] * A[i, :]
return A
def _sep_const_coeff(expr):
"""
Example
=======
>>> from sympy.logic.algorithms.lra_theory import _sep_const_coeff
>>> from sympy.abc import x, y
>>> _sep_const_coeff(2*x)
(x, 2)
>>> _sep_const_coeff(2*x + 3*y)
(2*x + 3*y, 1)
"""
if isinstance(expr, Add):
return expr, sympify(1)
if isinstance(expr, Mul):
coeffs = expr.args
else:
coeffs = [expr]
var, const = [], []
for c in coeffs:
c = sympify(c)
if len(c.free_symbols)==0:
const.append(c)
else:
var.append(c)
return Mul(*var), Mul(*const)
def _list_terms(expr):
if not isinstance(expr, Add):
return [expr]
return expr.args
def _sep_const_terms(expr):
"""
Example
=======
>>> from sympy.logic.algorithms.lra_theory import _sep_const_terms
>>> from sympy.abc import x, y
>>> _sep_const_terms(2*x + 3*y + 2)
(2*x + 3*y, 2)
"""
if isinstance(expr, Add):
terms = expr.args
else:
terms = [expr]
var, const = [], []
for t in terms:
if len(t.free_symbols) == 0:
const.append(t)
else:
var.append(t)
return sum(var), sum(const)
def _eval_binrel(binrel):
"""
Simplify binary relation to True / False if possible.
"""
if not (len(binrel.lhs.free_symbols) == 0 and len(binrel.rhs.free_symbols) == 0):
return binrel
if binrel.function == Q.lt:
res = binrel.lhs < binrel.rhs
elif binrel.function == Q.gt:
res = binrel.lhs > binrel.rhs
elif binrel.function == Q.le:
res = binrel.lhs <= binrel.rhs
elif binrel.function == Q.ge:
res = binrel.lhs >= binrel.rhs
elif binrel.function == Q.eq:
res = Eq(binrel.lhs, binrel.rhs)
elif binrel.function == Q.ne:
res = Ne(binrel.lhs, binrel.rhs)
if res == True or res == False:
return res
else:
return None
class Boundary:
"""
Represents an upper or lower bound or an equality between a symbol
and some constant.
"""
def __init__(self, var, const, upper, equality, strict=None):
if not equality in [True, False]:
assert equality in [True, False]
self.var = var
if isinstance(const, tuple):
s = const[1] != 0
if strict:
assert s == strict
self.bound = const[0]
self.strict = s
else:
self.bound = const
self.strict = strict
self.upper = upper if not equality else None
self.equality = equality
self.strict = strict
assert self.strict is not None
@staticmethod
def from_upper(var):
neg = -1 if var.upper_from_neg else 1
b = Boundary(var, var.upper[0], True, var.upper_from_eq, var.upper[1] != 0)
if neg < 0:
b = b.get_negated()
return b, neg
@staticmethod
def from_lower(var):
neg = -1 if var.lower_from_neg else 1
b = Boundary(var, var.lower[0], False, var.lower_from_eq, var.lower[1] != 0)
if neg < 0:
b = b.get_negated()
return b, neg
def get_negated(self):
return Boundary(self.var, self.bound, not self.upper, self.equality, not self.strict)
def get_inequality(self):
if self.equality:
return Eq(self.var.var, self.bound)
elif self.upper and self.strict:
return self.var.var < self.bound
elif not self.upper and self.strict:
return self.var.var > self.bound
elif self.upper:
return self.var.var <= self.bound
else:
return self.var.var >= self.bound
def __repr__(self):
return repr("Boundry(" + repr(self.get_inequality()) + ")")
def __eq__(self, other):
other = (other.var, other.bound, other.strict, other.upper, other.equality)
return (self.var, self.bound, self.strict, self.upper, self.equality) == other
def __hash__(self):
return hash((self.var, self.bound, self.strict, self.upper, self.equality))
class LRARational():
"""
Represents a rational plus or minus some amount
of arbitrary small deltas.
"""
def __init__(self, rational, delta):
self.value = (rational, delta)
def __lt__(self, other):
return self.value < other.value
def __le__(self, other):
return self.value <= other.value
def __eq__(self, other):
return self.value == other.value
def __add__(self, other):
return LRARational(self.value[0] + other.value[0], self.value[1] + other.value[1])
def __sub__(self, other):
return LRARational(self.value[0] - other.value[0], self.value[1] - other.value[1])
def __mul__(self, other):
assert not isinstance(other, LRARational)
return LRARational(self.value[0] * other, self.value[1] * other)
def __getitem__(self, index):
return self.value[index]
def __repr__(self):
return repr(self.value)
class LRAVariable():
"""
Object to keep track of upper and lower bounds
on `self.var`.
"""
def __init__(self, var):
self.upper = LRARational(float("inf"), 0)
self.upper_from_eq = False
self.upper_from_neg = False
self.lower = LRARational(-float("inf"), 0)
self.lower_from_eq = False
self.lower_from_neg = False
self.assign = LRARational(0,0)
self.var = var
self.col_idx = None
def __repr__(self):
return repr(self.var)
def __eq__(self, other):
if not isinstance(other, LRAVariable):
return False
return other.var == self.var
def __hash__(self):
return hash(self.var)
PK ]ZZZj�bV% % + sympy/logic/algorithms/minisat22_wrapper.pyfrom sympy.assumptions.cnf import EncodedCNF
def minisat22_satisfiable(expr, all_models=False, minimal=False):
if not isinstance(expr, EncodedCNF):
exprs = EncodedCNF()
exprs.add_prop(expr)
expr = exprs
from pysat.solvers import Minisat22
# Return UNSAT when False (encoded as 0) is present in the CNF
if {0} in expr.data:
if all_models:
return (f for f in [False])
return False
r = Minisat22(expr.data)
if minimal:
r.set_phases([-(i+1) for i in range(r.nof_vars())])
if not r.solve():
return False
if not all_models:
return {expr.symbols[abs(lit) - 1]: lit > 0 for lit in r.get_model()}
else:
# Make solutions SymPy compatible by creating a generator
def _gen(results):
satisfiable = False
while results.solve():
sol = results.get_model()
yield {expr.symbols[abs(lit) - 1]: lit > 0 for lit in sol}
if minimal:
results.add_clause([-i for i in sol if i>0])
else:
results.add_clause([-i for i in sol])
satisfiable = True
if not satisfiable:
yield False
raise StopIteration
return _gen(r)
PK ]ZZZ��b�� � ) sympy/logic/algorithms/pycosat_wrapper.pyfrom sympy.assumptions.cnf import EncodedCNF
def pycosat_satisfiable(expr, all_models=False):
import pycosat
if not isinstance(expr, EncodedCNF):
exprs = EncodedCNF()
exprs.add_prop(expr)
expr = exprs
# Return UNSAT when False (encoded as 0) is present in the CNF
if {0} in expr.data:
if all_models:
return (f for f in [False])
return False
if not all_models:
r = pycosat.solve(expr.data)
result = (r != "UNSAT")
if not result:
return result
return {expr.symbols[abs(lit) - 1]: lit > 0 for lit in r}
else:
r = pycosat.itersolve(expr.data)
result = (r != "UNSAT")
if not result:
return result
# Make solutions SymPy compatible by creating a generator
def _gen(results):
satisfiable = False
try:
while True:
sol = next(results)
yield {expr.symbols[abs(lit) - 1]: lit > 0 for lit in sol}
satisfiable = True
except StopIteration:
if not satisfiable:
yield False
return _gen(r)
PK ]ZZZ���$� � $ sympy/logic/algorithms/z3_wrapper.pyfrom sympy.printing.smtlib import smtlib_code
from sympy.assumptions.assume import AppliedPredicate
from sympy.assumptions.cnf import EncodedCNF
from sympy.assumptions.ask import Q
from sympy.core import Add, Mul
from sympy.core.relational import Equality, LessThan, GreaterThan, StrictLessThan, StrictGreaterThan
from sympy.functions.elementary.complexes import Abs
from sympy.functions.elementary.exponential import Pow
from sympy.functions.elementary.miscellaneous import Min, Max
from sympy.logic.boolalg import And, Or, Xor, Implies
from sympy.logic.boolalg import Not, ITE
from sympy.assumptions.relation.equality import StrictGreaterThanPredicate, StrictLessThanPredicate, GreaterThanPredicate, LessThanPredicate, EqualityPredicate
from sympy.external import import_module
def z3_satisfiable(expr, all_models=False):
if not isinstance(expr, EncodedCNF):
exprs = EncodedCNF()
exprs.add_prop(expr)
expr = exprs
z3 = import_module("z3")
if z3 is None:
raise ImportError("z3 is not installed")
s = encoded_cnf_to_z3_solver(expr, z3)
res = str(s.check())
if res == "unsat":
return False
elif res == "sat":
return z3_model_to_sympy_model(s.model(), expr)
else:
return None
def z3_model_to_sympy_model(z3_model, enc_cnf):
rev_enc = {value : key for key, value in enc_cnf.encoding.items()}
return {rev_enc[int(var.name()[1:])] : bool(z3_model[var]) for var in z3_model}
def clause_to_assertion(clause):
clause_strings = [f"d{abs(lit)}" if lit > 0 else f"(not d{abs(lit)})" for lit in clause]
return "(assert (or " + " ".join(clause_strings) + "))"
def encoded_cnf_to_z3_solver(enc_cnf, z3):
def dummify_bool(pred):
return False
assert isinstance(pred, AppliedPredicate)
if pred.function in [Q.positive, Q.negative, Q.zero]:
return pred
else:
return False
s = z3.Solver()
declarations = [f"(declare-const d{var} Bool)" for var in enc_cnf.variables]
assertions = [clause_to_assertion(clause) for clause in enc_cnf.data]
symbols = set()
for pred, enc in enc_cnf.encoding.items():
if not isinstance(pred, AppliedPredicate):
continue
if pred.function not in (Q.gt, Q.lt, Q.ge, Q.le, Q.ne, Q.eq, Q.positive, Q.negative, Q.extended_negative, Q.extended_positive, Q.zero, Q.nonzero, Q.nonnegative, Q.nonpositive, Q.extended_nonzero, Q.extended_nonnegative, Q.extended_nonpositive):
continue
pred_str = smtlib_code(pred, auto_declare=False, auto_assert=False, known_functions=known_functions)
symbols |= pred.free_symbols
pred = pred_str
clause = f"(implies d{enc} {pred})"
assertion = "(assert " + clause + ")"
assertions.append(assertion)
for sym in symbols:
declarations.append(f"(declare-const {sym} Real)")
declarations = "\n".join(declarations)
assertions = "\n".join(assertions)
s.from_string(declarations)
s.from_string(assertions)
return s
known_functions = {
Add: '+',
Mul: '*',
Equality: '=',
LessThan: '<=',
GreaterThan: '>=',
StrictLessThan: '<',
StrictGreaterThan: '>',
EqualityPredicate(): '=',
LessThanPredicate(): '<=',
GreaterThanPredicate(): '>=',
StrictLessThanPredicate(): '<',
StrictGreaterThanPredicate(): '>',
Abs: 'abs',
Min: 'min',
Max: 'max',
Pow: '^',
And: 'and',
Or: 'or',
Xor: 'xor',
Not: 'not',
ITE: 'ite',
Implies: '=>',
}
PK ]ZZZ�q7 7 ! sympy/logic/utilities/__init__.pyfrom .dimacs import load_file
__all__ = ['load_file']
PK ]ZZZg2�� sympy/logic/utilities/dimacs.py"""For reading in DIMACS file format
www.cs.ubc.ca/~hoos/SATLIB/Benchmarks/SAT/satformat.ps
"""
from sympy.core import Symbol
from sympy.logic.boolalg import And, Or
import re
def load(s):
"""Loads a boolean expression from a string.
Examples
========
>>> from sympy.logic.utilities.dimacs import load
>>> load('1')
cnf_1
>>> load('1 2')
cnf_1 | cnf_2
>>> load('1 \\n 2')
cnf_1 & cnf_2
>>> load('1 2 \\n 3')
cnf_3 & (cnf_1 | cnf_2)
"""
clauses = []
lines = s.split('\n')
pComment = re.compile(r'c.*')
pStats = re.compile(r'p\s*cnf\s*(\d*)\s*(\d*)')
while len(lines) > 0:
line = lines.pop(0)
# Only deal with lines that aren't comments
if not pComment.match(line):
m = pStats.match(line)
if not m:
nums = line.rstrip('\n').split(' ')
list = []
for lit in nums:
if lit != '':
if int(lit) == 0:
continue
num = abs(int(lit))
sign = True
if int(lit) < 0:
sign = False
if sign:
list.append(Symbol("cnf_%s" % num))
else:
list.append(~Symbol("cnf_%s" % num))
if len(list) > 0:
clauses.append(Or(*list))
return And(*clauses)
def load_file(location):
"""Loads a boolean expression from a file."""
with open(location) as f:
s = f.read()
return load(s)
PK ]ZZZ�W+J
J
sympy/matrices/__init__.py"""A module that handles matrices.
Includes functions for fast creating matrices like zero, one/eye, random
matrix, etc.
"""
from .exceptions import ShapeError, NonSquareMatrixError
from .kind import MatrixKind
from .dense import (
GramSchmidt, casoratian, diag, eye, hessian, jordan_cell,
list2numpy, matrix2numpy, matrix_multiply_elementwise, ones,
randMatrix, rot_axis1, rot_axis2, rot_axis3, rot_ccw_axis1,
rot_ccw_axis2, rot_ccw_axis3, rot_givens,
symarray, wronskian, zeros)
from .dense import MutableDenseMatrix
from .matrixbase import DeferredVector, MatrixBase
MutableMatrix = MutableDenseMatrix
Matrix = MutableMatrix
from .sparse import MutableSparseMatrix
from .sparsetools import banded
from .immutable import ImmutableDenseMatrix, ImmutableSparseMatrix
ImmutableMatrix = ImmutableDenseMatrix
SparseMatrix = MutableSparseMatrix
from .expressions import (
MatrixSlice, BlockDiagMatrix, BlockMatrix, FunctionMatrix, Identity,
Inverse, MatAdd, MatMul, MatPow, MatrixExpr, MatrixSymbol, Trace,
Transpose, ZeroMatrix, OneMatrix, blockcut, block_collapse, matrix_symbols, Adjoint,
hadamard_product, HadamardProduct, HadamardPower, Determinant, det,
diagonalize_vector, DiagMatrix, DiagonalMatrix, DiagonalOf, trace,
DotProduct, kronecker_product, KroneckerProduct,
PermutationMatrix, MatrixPermute, MatrixSet, Permanent, per)
from .utilities import dotprodsimp
__all__ = [
'ShapeError', 'NonSquareMatrixError', 'MatrixKind',
'GramSchmidt', 'casoratian', 'diag', 'eye', 'hessian', 'jordan_cell',
'list2numpy', 'matrix2numpy', 'matrix_multiply_elementwise', 'ones',
'randMatrix', 'rot_axis1', 'rot_axis2', 'rot_axis3', 'symarray',
'wronskian', 'zeros', 'rot_ccw_axis1', 'rot_ccw_axis2', 'rot_ccw_axis3',
'rot_givens',
'MutableDenseMatrix',
'DeferredVector', 'MatrixBase',
'Matrix', 'MutableMatrix',
'MutableSparseMatrix',
'banded',
'ImmutableDenseMatrix', 'ImmutableSparseMatrix',
'ImmutableMatrix', 'SparseMatrix',
'MatrixSlice', 'BlockDiagMatrix', 'BlockMatrix', 'FunctionMatrix',
'Identity', 'Inverse', 'MatAdd', 'MatMul', 'MatPow', 'MatrixExpr',
'MatrixSymbol', 'Trace', 'Transpose', 'ZeroMatrix', 'OneMatrix',
'blockcut', 'block_collapse', 'matrix_symbols', 'Adjoint',
'hadamard_product', 'HadamardProduct', 'HadamardPower', 'Determinant',
'det', 'diagonalize_vector', 'DiagMatrix', 'DiagonalMatrix',
'DiagonalOf', 'trace', 'DotProduct', 'kronecker_product',
'KroneckerProduct', 'PermutationMatrix', 'MatrixPermute', 'MatrixSet',
'Permanent', 'per',
'dotprodsimp',
]
PK ]ZZZ�v�i*u *u sympy/matrices/common.py"""
A module contining deprecated matrix mixin classes.
The classes in this module are deprecated and will be removed in a future
release. They are kept here for backwards compatibility in case downstream
code was subclassing them.
Importing anything else from this module is deprecated so anything here
should either not be used or should be imported from somewhere else.
"""
from collections import defaultdict
from collections.abc import Iterable
from inspect import isfunction
from functools import reduce
from sympy.assumptions.refine import refine
from sympy.core import SympifyError, Add
from sympy.core.basic import Atom
from sympy.core.decorators import call_highest_priority
from sympy.core.logic import fuzzy_and, FuzzyBool
from sympy.core.numbers import Integer
from sympy.core.mod import Mod
from sympy.core.singleton import S
from sympy.core.symbol import Symbol
from sympy.core.sympify import sympify
from sympy.functions.elementary.complexes import Abs, re, im
from sympy.utilities.exceptions import sympy_deprecation_warning
from .utilities import _dotprodsimp, _simplify
from sympy.polys.polytools import Poly
from sympy.utilities.iterables import flatten, is_sequence
from sympy.utilities.misc import as_int, filldedent
from sympy.tensor.array import NDimArray
from .utilities import _get_intermediate_simp_bool
# These exception types were previously defined in this module but were moved
# to exceptions.py. We reimport them here for backwards compatibility in case
# downstream code was importing them from here.
from .exceptions import ( # noqa: F401
MatrixError, ShapeError, NonSquareMatrixError, NonInvertibleMatrixError,
NonPositiveDefiniteMatrixError
)
_DEPRECATED_MIXINS = (
'MatrixShaping',
'MatrixSpecial',
'MatrixProperties',
'MatrixOperations',
'MatrixArithmetic',
'MatrixCommon',
'MatrixDeterminant',
'MatrixReductions',
'MatrixSubspaces',
'MatrixEigen',
'MatrixCalculus',
'MatrixDeprecated',
)
class _MatrixDeprecatedMeta(type):
#
# Override the default __instancecheck__ implementation to ensure that
# e.g. isinstance(M, MatrixCommon) still works when M is one of the
# matrix classes. Matrix no longer inherits from MatrixCommon so
# isinstance(M, MatrixCommon) would now return False by default.
#
# There were lots of places in the codebase where this was being done
# so it seems likely that downstream code may be doing it too. All use
# of these mixins is deprecated though so we give a deprecation warning
# unconditionally if they are being used with isinstance.
#
# Any code seeing this deprecation warning should be changed to use
# isinstance(M, MatrixBase) instead which also works in previous versions
# of SymPy.
#
def __instancecheck__(cls, instance):
sympy_deprecation_warning(
f"""
Checking whether an object is an instance of {cls.__name__} is
deprecated.
Use `isinstance(obj, Matrix)` instead of `isinstance(obj, {cls.__name__})`.
""",
deprecated_since_version="1.13",
active_deprecations_target="deprecated-matrix-mixins",
stacklevel=3,
)
from sympy.matrices.matrixbase import MatrixBase
from sympy.matrices.matrices import (
MatrixDeterminant,
MatrixReductions,
MatrixSubspaces,
MatrixEigen,
MatrixCalculus,
MatrixDeprecated
)
all_mixins = (
MatrixRequired,
MatrixShaping,
MatrixSpecial,
MatrixProperties,
MatrixOperations,
MatrixArithmetic,
MatrixCommon,
MatrixDeterminant,
MatrixReductions,
MatrixSubspaces,
MatrixEigen,
MatrixCalculus,
MatrixDeprecated
)
if cls in all_mixins and isinstance(instance, MatrixBase):
return True
else:
return super().__instancecheck__(instance)
class MatrixRequired(metaclass=_MatrixDeprecatedMeta):
"""Deprecated mixin class for making matrix classes."""
rows = None # type: int
cols = None # type: int
_simplify = None
def __init_subclass__(cls, **kwargs):
# Warn if any downstream code is subclassing this class or any of the
# deprecated mixin classes that are all ultimately subclasses of this
# class.
#
# We don't want to warn about the deprecated mixins themselves being
# created, but only about them being used as mixins by downstream code.
# Otherwise just importing this module would trigger a warning.
# Ultimately the whole module should be deprecated and removed but for
# SymPy 1.13 it is premature to do that given that this module was the
# main way to import matrix exception types in all previous versions.
if cls.__name__ not in _DEPRECATED_MIXINS:
sympy_deprecation_warning(
f"""
Inheriting from the Matrix mixin classes is deprecated.
The class {cls.__name__} is subclassing a deprecated mixin.
""",
deprecated_since_version="1.13",
active_deprecations_target="deprecated-matrix-mixins",
stacklevel=3,
)
super().__init_subclass__(**kwargs)
@classmethod
def _new(cls, *args, **kwargs):
"""`_new` must, at minimum, be callable as
`_new(rows, cols, mat) where mat is a flat list of the
elements of the matrix."""
raise NotImplementedError("Subclasses must implement this.")
def __eq__(self, other):
raise NotImplementedError("Subclasses must implement this.")
def __getitem__(self, key):
"""Implementations of __getitem__ should accept ints, in which
case the matrix is indexed as a flat list, tuples (i,j) in which
case the (i,j) entry is returned, slices, or mixed tuples (a,b)
where a and b are any combination of slices and integers."""
raise NotImplementedError("Subclasses must implement this.")
def __len__(self):
"""The total number of entries in the matrix."""
raise NotImplementedError("Subclasses must implement this.")
@property
def shape(self):
raise NotImplementedError("Subclasses must implement this.")
class MatrixShaping(MatrixRequired):
"""Provides basic matrix shaping and extracting of submatrices"""
def _eval_col_del(self, col):
def entry(i, j):
return self[i, j] if j < col else self[i, j + 1]
return self._new(self.rows, self.cols - 1, entry)
def _eval_col_insert(self, pos, other):
def entry(i, j):
if j < pos:
return self[i, j]
elif pos <= j < pos + other.cols:
return other[i, j - pos]
return self[i, j - other.cols]
return self._new(self.rows, self.cols + other.cols, entry)
def _eval_col_join(self, other):
rows = self.rows
def entry(i, j):
if i < rows:
return self[i, j]
return other[i - rows, j]
return classof(self, other)._new(self.rows + other.rows, self.cols,
entry)
def _eval_extract(self, rowsList, colsList):
mat = list(self)
cols = self.cols
indices = (i * cols + j for i in rowsList for j in colsList)
return self._new(len(rowsList), len(colsList),
[mat[i] for i in indices])
def _eval_get_diag_blocks(self):
sub_blocks = []
def recurse_sub_blocks(M):
i = 1
while i <= M.shape[0]:
if i == 1:
to_the_right = M[0, i:]
to_the_bottom = M[i:, 0]
else:
to_the_right = M[:i, i:]
to_the_bottom = M[i:, :i]
if any(to_the_right) or any(to_the_bottom):
i += 1
continue
else:
sub_blocks.append(M[:i, :i])
if M.shape == M[:i, :i].shape:
return
else:
recurse_sub_blocks(M[i:, i:])
return
recurse_sub_blocks(self)
return sub_blocks
def _eval_row_del(self, row):
def entry(i, j):
return self[i, j] if i < row else self[i + 1, j]
return self._new(self.rows - 1, self.cols, entry)
def _eval_row_insert(self, pos, other):
entries = list(self)
insert_pos = pos * self.cols
entries[insert_pos:insert_pos] = list(other)
return self._new(self.rows + other.rows, self.cols, entries)
def _eval_row_join(self, other):
cols = self.cols
def entry(i, j):
if j < cols:
return self[i, j]
return other[i, j - cols]
return classof(self, other)._new(self.rows, self.cols + other.cols,
entry)
def _eval_tolist(self):
return [list(self[i,:]) for i in range(self.rows)]
def _eval_todok(self):
dok = {}
rows, cols = self.shape
for i in range(rows):
for j in range(cols):
val = self[i, j]
if val != self.zero:
dok[i, j] = val
return dok
def _eval_vec(self):
rows = self.rows
def entry(n, _):
# we want to read off the columns first
j = n // rows
i = n - j * rows
return self[i, j]
return self._new(len(self), 1, entry)
def _eval_vech(self, diagonal):
c = self.cols
v = []
if diagonal:
for j in range(c):
for i in range(j, c):
v.append(self[i, j])
else:
for j in range(c):
for i in range(j + 1, c):
v.append(self[i, j])
return self._new(len(v), 1, v)
def col_del(self, col):
"""Delete the specified column."""
if col < 0:
col += self.cols
if not 0 <= col < self.cols:
raise IndexError("Column {} is out of range.".format(col))
return self._eval_col_del(col)
def col_insert(self, pos, other):
"""Insert one or more columns at the given column position.
Examples
========
>>> from sympy import zeros, ones
>>> M = zeros(3)
>>> V = ones(3, 1)
>>> M.col_insert(1, V)
Matrix([
[0, 1, 0, 0],
[0, 1, 0, 0],
[0, 1, 0, 0]])
See Also
========
col
row_insert
"""
# Allows you to build a matrix even if it is null matrix
if not self:
return type(self)(other)
pos = as_int(pos)
if pos < 0:
pos = self.cols + pos
if pos < 0:
pos = 0
elif pos > self.cols:
pos = self.cols
if self.rows != other.rows:
raise ShapeError(
"The matrices have incompatible number of rows ({} and {})"
.format(self.rows, other.rows))
return self._eval_col_insert(pos, other)
def col_join(self, other):
"""Concatenates two matrices along self's last and other's first row.
Examples
========
>>> from sympy import zeros, ones
>>> M = zeros(3)
>>> V = ones(1, 3)
>>> M.col_join(V)
Matrix([
[0, 0, 0],
[0, 0, 0],
[0, 0, 0],
[1, 1, 1]])
See Also
========
col
row_join
"""
# A null matrix can always be stacked (see #10770)
if self.rows == 0 and self.cols != other.cols:
return self._new(0, other.cols, []).col_join(other)
if self.cols != other.cols:
raise ShapeError(
"The matrices have incompatible number of columns ({} and {})"
.format(self.cols, other.cols))
return self._eval_col_join(other)
def col(self, j):
"""Elementary column selector.
Examples
========
>>> from sympy import eye
>>> eye(2).col(0)
Matrix([
[1],
[0]])
See Also
========
row
col_del
col_join
col_insert
"""
return self[:, j]
def extract(self, rowsList, colsList):
r"""Return a submatrix by specifying a list of rows and columns.
Negative indices can be given. All indices must be in the range
$-n \le i < n$ where $n$ is the number of rows or columns.
Examples
========
>>> from sympy import Matrix
>>> m = Matrix(4, 3, range(12))
>>> m
Matrix([
[0, 1, 2],
[3, 4, 5],
[6, 7, 8],
[9, 10, 11]])
>>> m.extract([0, 1, 3], [0, 1])
Matrix([
[0, 1],
[3, 4],
[9, 10]])
Rows or columns can be repeated:
>>> m.extract([0, 0, 1], [-1])
Matrix([
[2],
[2],
[5]])
Every other row can be taken by using range to provide the indices:
>>> m.extract(range(0, m.rows, 2), [-1])
Matrix([
[2],
[8]])
RowsList or colsList can also be a list of booleans, in which case
the rows or columns corresponding to the True values will be selected:
>>> m.extract([0, 1, 2, 3], [True, False, True])
Matrix([
[0, 2],
[3, 5],
[6, 8],
[9, 11]])
"""
if not is_sequence(rowsList) or not is_sequence(colsList):
raise TypeError("rowsList and colsList must be iterable")
# ensure rowsList and colsList are lists of integers
if rowsList and all(isinstance(i, bool) for i in rowsList):
rowsList = [index for index, item in enumerate(rowsList) if item]
if colsList and all(isinstance(i, bool) for i in colsList):
colsList = [index for index, item in enumerate(colsList) if item]
# ensure everything is in range
rowsList = [a2idx(k, self.rows) for k in rowsList]
colsList = [a2idx(k, self.cols) for k in colsList]
return self._eval_extract(rowsList, colsList)
def get_diag_blocks(self):
"""Obtains the square sub-matrices on the main diagonal of a square matrix.
Useful for inverting symbolic matrices or solving systems of
linear equations which may be decoupled by having a block diagonal
structure.
Examples
========
>>> from sympy import Matrix
>>> from sympy.abc import x, y, z
>>> A = Matrix([[1, 3, 0, 0], [y, z*z, 0, 0], [0, 0, x, 0], [0, 0, 0, 0]])
>>> a1, a2, a3 = A.get_diag_blocks()
>>> a1
Matrix([
[1, 3],
[y, z**2]])
>>> a2
Matrix([[x]])
>>> a3
Matrix([[0]])
"""
return self._eval_get_diag_blocks()
@classmethod
def hstack(cls, *args):
"""Return a matrix formed by joining args horizontally (i.e.
by repeated application of row_join).
Examples
========
>>> from sympy import Matrix, eye
>>> Matrix.hstack(eye(2), 2*eye(2))
Matrix([
[1, 0, 2, 0],
[0, 1, 0, 2]])
"""
if len(args) == 0:
return cls._new()
kls = type(args[0])
return reduce(kls.row_join, args)
def reshape(self, rows, cols):
"""Reshape the matrix. Total number of elements must remain the same.
Examples
========
>>> from sympy import Matrix
>>> m = Matrix(2, 3, lambda i, j: 1)
>>> m
Matrix([
[1, 1, 1],
[1, 1, 1]])
>>> m.reshape(1, 6)
Matrix([[1, 1, 1, 1, 1, 1]])
>>> m.reshape(3, 2)
Matrix([
[1, 1],
[1, 1],
[1, 1]])
"""
if self.rows * self.cols != rows * cols:
raise ValueError("Invalid reshape parameters %d %d" % (rows, cols))
return self._new(rows, cols, lambda i, j: self[i * cols + j])
def row_del(self, row):
"""Delete the specified row."""
if row < 0:
row += self.rows
if not 0 <= row < self.rows:
raise IndexError("Row {} is out of range.".format(row))
return self._eval_row_del(row)
def row_insert(self, pos, other):
"""Insert one or more rows at the given row position.
Examples
========
>>> from sympy import zeros, ones
>>> M = zeros(3)
>>> V = ones(1, 3)
>>> M.row_insert(1, V)
Matrix([
[0, 0, 0],
[1, 1, 1],
[0, 0, 0],
[0, 0, 0]])
See Also
========
row
col_insert
"""
# Allows you to build a matrix even if it is null matrix
if not self:
return self._new(other)
pos = as_int(pos)
if pos < 0:
pos = self.rows + pos
if pos < 0:
pos = 0
elif pos > self.rows:
pos = self.rows
if self.cols != other.cols:
raise ShapeError(
"The matrices have incompatible number of columns ({} and {})"
.format(self.cols, other.cols))
return self._eval_row_insert(pos, other)
def row_join(self, other):
"""Concatenates two matrices along self's last and rhs's first column
Examples
========
>>> from sympy import zeros, ones
>>> M = zeros(3)
>>> V = ones(3, 1)
>>> M.row_join(V)
Matrix([
[0, 0, 0, 1],
[0, 0, 0, 1],
[0, 0, 0, 1]])
See Also
========
row
col_join
"""
# A null matrix can always be stacked (see #10770)
if self.cols == 0 and self.rows != other.rows:
return self._new(other.rows, 0, []).row_join(other)
if self.rows != other.rows:
raise ShapeError(
"The matrices have incompatible number of rows ({} and {})"
.format(self.rows, other.rows))
return self._eval_row_join(other)
def diagonal(self, k=0):
"""Returns the kth diagonal of self. The main diagonal
corresponds to `k=0`; diagonals above and below correspond to
`k > 0` and `k < 0`, respectively. The values of `self[i, j]`
for which `j - i = k`, are returned in order of increasing
`i + j`, starting with `i + j = |k|`.
Examples
========
>>> from sympy import Matrix
>>> m = Matrix(3, 3, lambda i, j: j - i); m
Matrix([
[ 0, 1, 2],
[-1, 0, 1],
[-2, -1, 0]])
>>> _.diagonal()
Matrix([[0, 0, 0]])
>>> m.diagonal(1)
Matrix([[1, 1]])
>>> m.diagonal(-2)
Matrix([[-2]])
Even though the diagonal is returned as a Matrix, the element
retrieval can be done with a single index:
>>> Matrix.diag(1, 2, 3).diagonal()[1] # instead of [0, 1]
2
See Also
========
diag
"""
rv = []
k = as_int(k)
r = 0 if k > 0 else -k
c = 0 if r else k
while True:
if r == self.rows or c == self.cols:
break
rv.append(self[r, c])
r += 1
c += 1
if not rv:
raise ValueError(filldedent('''
The %s diagonal is out of range [%s, %s]''' % (
k, 1 - self.rows, self.cols - 1)))
return self._new(1, len(rv), rv)
def row(self, i):
"""Elementary row selector.
Examples
========
>>> from sympy import eye
>>> eye(2).row(0)
Matrix([[1, 0]])
See Also
========
col
row_del
row_join
row_insert
"""
return self[i, :]
@property
def shape(self):
"""The shape (dimensions) of the matrix as the 2-tuple (rows, cols).
Examples
========
>>> from sympy import zeros
>>> M = zeros(2, 3)
>>> M.shape
(2, 3)
>>> M.rows
2
>>> M.cols
3
"""
return (self.rows, self.cols)
def todok(self):
"""Return the matrix as dictionary of keys.
Examples
========
>>> from sympy import Matrix
>>> M = Matrix.eye(3)
>>> M.todok()
{(0, 0): 1, (1, 1): 1, (2, 2): 1}
"""
return self._eval_todok()
def tolist(self):
"""Return the Matrix as a nested Python list.
Examples
========
>>> from sympy import Matrix, ones
>>> m = Matrix(3, 3, range(9))
>>> m
Matrix([
[0, 1, 2],
[3, 4, 5],
[6, 7, 8]])
>>> m.tolist()
[[0, 1, 2], [3, 4, 5], [6, 7, 8]]
>>> ones(3, 0).tolist()
[[], [], []]
When there are no rows then it will not be possible to tell how
many columns were in the original matrix:
>>> ones(0, 3).tolist()
[]
"""
if not self.rows:
return []
if not self.cols:
return [[] for i in range(self.rows)]
return self._eval_tolist()
def todod(M):
"""Returns matrix as dict of dicts containing non-zero elements of the Matrix
Examples
========
>>> from sympy import Matrix
>>> A = Matrix([[0, 1],[0, 3]])
>>> A
Matrix([
[0, 1],
[0, 3]])
>>> A.todod()
{0: {1: 1}, 1: {1: 3}}
"""
rowsdict = {}
Mlol = M.tolist()
for i, Mi in enumerate(Mlol):
row = {j: Mij for j, Mij in enumerate(Mi) if Mij}
if row:
rowsdict[i] = row
return rowsdict
def vec(self):
"""Return the Matrix converted into a one column matrix by stacking columns
Examples
========
>>> from sympy import Matrix
>>> m=Matrix([[1, 3], [2, 4]])
>>> m
Matrix([
[1, 3],
[2, 4]])
>>> m.vec()
Matrix([
[1],
[2],
[3],
[4]])
See Also
========
vech
"""
return self._eval_vec()
def vech(self, diagonal=True, check_symmetry=True):
"""Reshapes the matrix into a column vector by stacking the
elements in the lower triangle.
Parameters
==========
diagonal : bool, optional
If ``True``, it includes the diagonal elements.
check_symmetry : bool, optional
If ``True``, it checks whether the matrix is symmetric.
Examples
========
>>> from sympy import Matrix
>>> m=Matrix([[1, 2], [2, 3]])
>>> m
Matrix([
[1, 2],
[2, 3]])
>>> m.vech()
Matrix([
[1],
[2],
[3]])
>>> m.vech(diagonal=False)
Matrix([[2]])
Notes
=====
This should work for symmetric matrices and ``vech`` can
represent symmetric matrices in vector form with less size than
``vec``.
See Also
========
vec
"""
if not self.is_square:
raise NonSquareMatrixError
if check_symmetry and not self.is_symmetric():
raise ValueError("The matrix is not symmetric.")
return self._eval_vech(diagonal)
@classmethod
def vstack(cls, *args):
"""Return a matrix formed by joining args vertically (i.e.
by repeated application of col_join).
Examples
========
>>> from sympy import Matrix, eye
>>> Matrix.vstack(eye(2), 2*eye(2))
Matrix([
[1, 0],
[0, 1],
[2, 0],
[0, 2]])
"""
if len(args) == 0:
return cls._new()
kls = type(args[0])
return reduce(kls.col_join, args)
class MatrixSpecial(MatrixRequired):
"""Construction of special matrices"""
@classmethod
def _eval_diag(cls, rows, cols, diag_dict):
"""diag_dict is a defaultdict containing
all the entries of the diagonal matrix."""
def entry(i, j):
return diag_dict[(i, j)]
return cls._new(rows, cols, entry)
@classmethod
def _eval_eye(cls, rows, cols):
vals = [cls.zero]*(rows*cols)
vals[::cols+1] = [cls.one]*min(rows, cols)
return cls._new(rows, cols, vals, copy=False)
@classmethod
def _eval_jordan_block(cls, size: int, eigenvalue, band='upper'):
if band == 'lower':
def entry(i, j):
if i == j:
return eigenvalue
elif j + 1 == i:
return cls.one
return cls.zero
else:
def entry(i, j):
if i == j:
return eigenvalue
elif i + 1 == j:
return cls.one
return cls.zero
return cls._new(size, size, entry)
@classmethod
def _eval_ones(cls, rows, cols):
def entry(i, j):
return cls.one
return cls._new(rows, cols, entry)
@classmethod
def _eval_zeros(cls, rows, cols):
return cls._new(rows, cols, [cls.zero]*(rows*cols), copy=False)
@classmethod
def _eval_wilkinson(cls, n):
def entry(i, j):
return cls.one if i + 1 == j else cls.zero
D = cls._new(2*n + 1, 2*n + 1, entry)
wminus = cls.diag(list(range(-n, n + 1)), unpack=True) + D + D.T
wplus = abs(cls.diag(list(range(-n, n + 1)), unpack=True)) + D + D.T
return wminus, wplus
@classmethod
def diag(kls, *args, strict=False, unpack=True, rows=None, cols=None, **kwargs):
"""Returns a matrix with the specified diagonal.
If matrices are passed, a block-diagonal matrix
is created (i.e. the "direct sum" of the matrices).
kwargs
======
rows : rows of the resulting matrix; computed if
not given.
cols : columns of the resulting matrix; computed if
not given.
cls : class for the resulting matrix
unpack : bool which, when True (default), unpacks a single
sequence rather than interpreting it as a Matrix.
strict : bool which, when False (default), allows Matrices to
have variable-length rows.
Examples
========
>>> from sympy import Matrix
>>> Matrix.diag(1, 2, 3)
Matrix([
[1, 0, 0],
[0, 2, 0],
[0, 0, 3]])
The current default is to unpack a single sequence. If this is
not desired, set `unpack=False` and it will be interpreted as
a matrix.
>>> Matrix.diag([1, 2, 3]) == Matrix.diag(1, 2, 3)
True
When more than one element is passed, each is interpreted as
something to put on the diagonal. Lists are converted to
matrices. Filling of the diagonal always continues from
the bottom right hand corner of the previous item: this
will create a block-diagonal matrix whether the matrices
are square or not.
>>> col = [1, 2, 3]
>>> row = [[4, 5]]
>>> Matrix.diag(col, row)
Matrix([
[1, 0, 0],
[2, 0, 0],
[3, 0, 0],
[0, 4, 5]])
When `unpack` is False, elements within a list need not all be
of the same length. Setting `strict` to True would raise a
ValueError for the following:
>>> Matrix.diag([[1, 2, 3], [4, 5], [6]], unpack=False)
Matrix([
[1, 2, 3],
[4, 5, 0],
[6, 0, 0]])
The type of the returned matrix can be set with the ``cls``
keyword.
>>> from sympy import ImmutableMatrix
>>> from sympy.utilities.misc import func_name
>>> func_name(Matrix.diag(1, cls=ImmutableMatrix))
'ImmutableDenseMatrix'
A zero dimension matrix can be used to position the start of
the filling at the start of an arbitrary row or column:
>>> from sympy import ones
>>> r2 = ones(0, 2)
>>> Matrix.diag(r2, 1, 2)
Matrix([
[0, 0, 1, 0],
[0, 0, 0, 2]])
See Also
========
eye
diagonal
.dense.diag
.expressions.blockmatrix.BlockMatrix
.sparsetools.banded
"""
from sympy.matrices.matrixbase import MatrixBase
from sympy.matrices.dense import Matrix
from sympy.matrices import SparseMatrix
klass = kwargs.get('cls', kls)
if unpack and len(args) == 1 and is_sequence(args[0]) and \
not isinstance(args[0], MatrixBase):
args = args[0]
# fill a default dict with the diagonal entries
diag_entries = defaultdict(int)
rmax = cmax = 0 # keep track of the biggest index seen
for m in args:
if isinstance(m, list):
if strict:
# if malformed, Matrix will raise an error
_ = Matrix(m)
r, c = _.shape
m = _.tolist()
else:
r, c, smat = SparseMatrix._handle_creation_inputs(m)
for (i, j), _ in smat.items():
diag_entries[(i + rmax, j + cmax)] = _
m = [] # to skip process below
elif hasattr(m, 'shape'): # a Matrix
# convert to list of lists
r, c = m.shape
m = m.tolist()
else: # in this case, we're a single value
diag_entries[(rmax, cmax)] = m
rmax += 1
cmax += 1
continue
# process list of lists
for i, mi in enumerate(m):
for j, _ in enumerate(mi):
diag_entries[(i + rmax, j + cmax)] = _
rmax += r
cmax += c
if rows is None:
rows, cols = cols, rows
if rows is None:
rows, cols = rmax, cmax
else:
cols = rows if cols is None else cols
if rows < rmax or cols < cmax:
raise ValueError(filldedent('''
The constructed matrix is {} x {} but a size of {} x {}
was specified.'''.format(rmax, cmax, rows, cols)))
return klass._eval_diag(rows, cols, diag_entries)
@classmethod
def eye(kls, rows, cols=None, **kwargs):
"""Returns an identity matrix.
Parameters
==========
rows : rows of the matrix
cols : cols of the matrix (if None, cols=rows)
kwargs
======
cls : class of the returned matrix
"""
if cols is None:
cols = rows
if rows < 0 or cols < 0:
raise ValueError("Cannot create a {} x {} matrix. "
"Both dimensions must be positive".format(rows, cols))
klass = kwargs.get('cls', kls)
rows, cols = as_int(rows), as_int(cols)
return klass._eval_eye(rows, cols)
@classmethod
def jordan_block(kls, size=None, eigenvalue=None, *, band='upper', **kwargs):
"""Returns a Jordan block
Parameters
==========
size : Integer, optional
Specifies the shape of the Jordan block matrix.
eigenvalue : Number or Symbol
Specifies the value for the main diagonal of the matrix.
.. note::
The keyword ``eigenval`` is also specified as an alias
of this keyword, but it is not recommended to use.
We may deprecate the alias in later release.
band : 'upper' or 'lower', optional
Specifies the position of the off-diagonal to put `1` s on.
cls : Matrix, optional
Specifies the matrix class of the output form.
If it is not specified, the class type where the method is
being executed on will be returned.
Returns
=======
Matrix
A Jordan block matrix.
Raises
======
ValueError
If insufficient arguments are given for matrix size
specification, or no eigenvalue is given.
Examples
========
Creating a default Jordan block:
>>> from sympy import Matrix
>>> from sympy.abc import x
>>> Matrix.jordan_block(4, x)
Matrix([
[x, 1, 0, 0],
[0, x, 1, 0],
[0, 0, x, 1],
[0, 0, 0, x]])
Creating an alternative Jordan block matrix where `1` is on
lower off-diagonal:
>>> Matrix.jordan_block(4, x, band='lower')
Matrix([
[x, 0, 0, 0],
[1, x, 0, 0],
[0, 1, x, 0],
[0, 0, 1, x]])
Creating a Jordan block with keyword arguments
>>> Matrix.jordan_block(size=4, eigenvalue=x)
Matrix([
[x, 1, 0, 0],
[0, x, 1, 0],
[0, 0, x, 1],
[0, 0, 0, x]])
References
==========
.. [1] https://en.wikipedia.org/wiki/Jordan_matrix
"""
klass = kwargs.pop('cls', kls)
eigenval = kwargs.get('eigenval', None)
if eigenvalue is None and eigenval is None:
raise ValueError("Must supply an eigenvalue")
elif eigenvalue != eigenval and None not in (eigenval, eigenvalue):
raise ValueError(
"Inconsistent values are given: 'eigenval'={}, "
"'eigenvalue'={}".format(eigenval, eigenvalue))
else:
if eigenval is not None:
eigenvalue = eigenval
if size is None:
raise ValueError("Must supply a matrix size")
size = as_int(size)
return klass._eval_jordan_block(size, eigenvalue, band)
@classmethod
def ones(kls, rows, cols=None, **kwargs):
"""Returns a matrix of ones.
Parameters
==========
rows : rows of the matrix
cols : cols of the matrix (if None, cols=rows)
kwargs
======
cls : class of the returned matrix
"""
if cols is None:
cols = rows
klass = kwargs.get('cls', kls)
rows, cols = as_int(rows), as_int(cols)
return klass._eval_ones(rows, cols)
@classmethod
def zeros(kls, rows, cols=None, **kwargs):
"""Returns a matrix of zeros.
Parameters
==========
rows : rows of the matrix
cols : cols of the matrix (if None, cols=rows)
kwargs
======
cls : class of the returned matrix
"""
if cols is None:
cols = rows
if rows < 0 or cols < 0:
raise ValueError("Cannot create a {} x {} matrix. "
"Both dimensions must be positive".format(rows, cols))
klass = kwargs.get('cls', kls)
rows, cols = as_int(rows), as_int(cols)
return klass._eval_zeros(rows, cols)
@classmethod
def companion(kls, poly):
"""Returns a companion matrix of a polynomial.
Examples
========
>>> from sympy import Matrix, Poly, Symbol, symbols
>>> x = Symbol('x')
>>> c0, c1, c2, c3, c4 = symbols('c0:5')
>>> p = Poly(c0 + c1*x + c2*x**2 + c3*x**3 + c4*x**4 + x**5, x)
>>> Matrix.companion(p)
Matrix([
[0, 0, 0, 0, -c0],
[1, 0, 0, 0, -c1],
[0, 1, 0, 0, -c2],
[0, 0, 1, 0, -c3],
[0, 0, 0, 1, -c4]])
"""
poly = kls._sympify(poly)
if not isinstance(poly, Poly):
raise ValueError("{} must be a Poly instance.".format(poly))
if not poly.is_monic:
raise ValueError("{} must be a monic polynomial.".format(poly))
if not poly.is_univariate:
raise ValueError(
"{} must be a univariate polynomial.".format(poly))
size = poly.degree()
if not size >= 1:
raise ValueError(
"{} must have degree not less than 1.".format(poly))
coeffs = poly.all_coeffs()
def entry(i, j):
if j == size - 1:
return -coeffs[-1 - i]
elif i == j + 1:
return kls.one
return kls.zero
return kls._new(size, size, entry)
@classmethod
def wilkinson(kls, n, **kwargs):
"""Returns two square Wilkinson Matrix of size 2*n + 1
$W_{2n + 1}^-, W_{2n + 1}^+ =$ Wilkinson(n)
Examples
========
>>> from sympy import Matrix
>>> wminus, wplus = Matrix.wilkinson(3)
>>> wminus
Matrix([
[-3, 1, 0, 0, 0, 0, 0],
[ 1, -2, 1, 0, 0, 0, 0],
[ 0, 1, -1, 1, 0, 0, 0],
[ 0, 0, 1, 0, 1, 0, 0],
[ 0, 0, 0, 1, 1, 1, 0],
[ 0, 0, 0, 0, 1, 2, 1],
[ 0, 0, 0, 0, 0, 1, 3]])
>>> wplus
Matrix([
[3, 1, 0, 0, 0, 0, 0],
[1, 2, 1, 0, 0, 0, 0],
[0, 1, 1, 1, 0, 0, 0],
[0, 0, 1, 0, 1, 0, 0],
[0, 0, 0, 1, 1, 1, 0],
[0, 0, 0, 0, 1, 2, 1],
[0, 0, 0, 0, 0, 1, 3]])
References
==========
.. [1] https://blogs.mathworks.com/cleve/2013/04/15/wilkinsons-matrices-2/
.. [2] J. H. Wilkinson, The Algebraic Eigenvalue Problem, Claredon Press, Oxford, 1965, 662 pp.
"""
klass = kwargs.get('cls', kls)
n = as_int(n)
return klass._eval_wilkinson(n)
class MatrixProperties(MatrixRequired):
"""Provides basic properties of a matrix."""
def _eval_atoms(self, *types):
result = set()
for i in self:
result.update(i.atoms(*types))
return result
def _eval_free_symbols(self):
return set().union(*(i.free_symbols for i in self if i))
def _eval_has(self, *patterns):
return any(a.has(*patterns) for a in self)
def _eval_is_anti_symmetric(self, simpfunc):
if not all(simpfunc(self[i, j] + self[j, i]).is_zero for i in range(self.rows) for j in range(self.cols)):
return False
return True
def _eval_is_diagonal(self):
for i in range(self.rows):
for j in range(self.cols):
if i != j and self[i, j]:
return False
return True
# _eval_is_hermitian is called by some general SymPy
# routines and has a different *args signature. Make
# sure the names don't clash by adding `_matrix_` in name.
def _eval_is_matrix_hermitian(self, simpfunc):
mat = self._new(self.rows, self.cols, lambda i, j: simpfunc(self[i, j] - self[j, i].conjugate()))
return mat.is_zero_matrix
def _eval_is_Identity(self) -> FuzzyBool:
def dirac(i, j):
if i == j:
return 1
return 0
return all(self[i, j] == dirac(i, j)
for i in range(self.rows)
for j in range(self.cols))
def _eval_is_lower_hessenberg(self):
return all(self[i, j].is_zero
for i in range(self.rows)
for j in range(i + 2, self.cols))
def _eval_is_lower(self):
return all(self[i, j].is_zero
for i in range(self.rows)
for j in range(i + 1, self.cols))
def _eval_is_symbolic(self):
return self.has(Symbol)
def _eval_is_symmetric(self, simpfunc):
mat = self._new(self.rows, self.cols, lambda i, j: simpfunc(self[i, j] - self[j, i]))
return mat.is_zero_matrix
def _eval_is_zero_matrix(self):
if any(i.is_zero == False for i in self):
return False
if any(i.is_zero is None for i in self):
return None
return True
def _eval_is_upper_hessenberg(self):
return all(self[i, j].is_zero
for i in range(2, self.rows)
for j in range(min(self.cols, (i - 1))))
def _eval_values(self):
return [i for i in self if not i.is_zero]
def _has_positive_diagonals(self):
diagonal_entries = (self[i, i] for i in range(self.rows))
return fuzzy_and(x.is_positive for x in diagonal_entries)
def _has_nonnegative_diagonals(self):
diagonal_entries = (self[i, i] for i in range(self.rows))
return fuzzy_and(x.is_nonnegative for x in diagonal_entries)
def atoms(self, *types):
"""Returns the atoms that form the current object.
Examples
========
>>> from sympy.abc import x, y
>>> from sympy import Matrix
>>> Matrix([[x]])
Matrix([[x]])
>>> _.atoms()
{x}
>>> Matrix([[x, y], [y, x]])
Matrix([
[x, y],
[y, x]])
>>> _.atoms()
{x, y}
"""
types = tuple(t if isinstance(t, type) else type(t) for t in types)
if not types:
types = (Atom,)
return self._eval_atoms(*types)
@property
def free_symbols(self):
"""Returns the free symbols within the matrix.
Examples
========
>>> from sympy.abc import x
>>> from sympy import Matrix
>>> Matrix([[x], [1]]).free_symbols
{x}
"""
return self._eval_free_symbols()
def has(self, *patterns):
"""Test whether any subexpression matches any of the patterns.
Examples
========
>>> from sympy import Matrix, SparseMatrix, Float
>>> from sympy.abc import x, y
>>> A = Matrix(((1, x), (0.2, 3)))
>>> B = SparseMatrix(((1, x), (0.2, 3)))
>>> A.has(x)
True
>>> A.has(y)
False
>>> A.has(Float)
True
>>> B.has(x)
True
>>> B.has(y)
False
>>> B.has(Float)
True
"""
return self._eval_has(*patterns)
def is_anti_symmetric(self, simplify=True):
"""Check if matrix M is an antisymmetric matrix,
that is, M is a square matrix with all M[i, j] == -M[j, i].
When ``simplify=True`` (default), the sum M[i, j] + M[j, i] is
simplified before testing to see if it is zero. By default,
the SymPy simplify function is used. To use a custom function
set simplify to a function that accepts a single argument which
returns a simplified expression. To skip simplification, set
simplify to False but note that although this will be faster,
it may induce false negatives.
Examples
========
>>> from sympy import Matrix, symbols
>>> m = Matrix(2, 2, [0, 1, -1, 0])
>>> m
Matrix([
[ 0, 1],
[-1, 0]])
>>> m.is_anti_symmetric()
True
>>> x, y = symbols('x y')
>>> m = Matrix(2, 3, [0, 0, x, -y, 0, 0])
>>> m
Matrix([
[ 0, 0, x],
[-y, 0, 0]])
>>> m.is_anti_symmetric()
False
>>> from sympy.abc import x, y
>>> m = Matrix(3, 3, [0, x**2 + 2*x + 1, y,
... -(x + 1)**2, 0, x*y,
... -y, -x*y, 0])
Simplification of matrix elements is done by default so even
though two elements which should be equal and opposite would not
pass an equality test, the matrix is still reported as
anti-symmetric:
>>> m[0, 1] == -m[1, 0]
False
>>> m.is_anti_symmetric()
True
If ``simplify=False`` is used for the case when a Matrix is already
simplified, this will speed things up. Here, we see that without
simplification the matrix does not appear anti-symmetric:
>>> print(m.is_anti_symmetric(simplify=False))
None
But if the matrix were already expanded, then it would appear
anti-symmetric and simplification in the is_anti_symmetric routine
is not needed:
>>> m = m.expand()
>>> m.is_anti_symmetric(simplify=False)
True
"""
# accept custom simplification
simpfunc = simplify
if not isfunction(simplify):
simpfunc = _simplify if simplify else lambda x: x
if not self.is_square:
return False
return self._eval_is_anti_symmetric(simpfunc)
def is_diagonal(self):
"""Check if matrix is diagonal,
that is matrix in which the entries outside the main diagonal are all zero.
Examples
========
>>> from sympy import Matrix, diag
>>> m = Matrix(2, 2, [1, 0, 0, 2])
>>> m
Matrix([
[1, 0],
[0, 2]])
>>> m.is_diagonal()
True
>>> m = Matrix(2, 2, [1, 1, 0, 2])
>>> m
Matrix([
[1, 1],
[0, 2]])
>>> m.is_diagonal()
False
>>> m = diag(1, 2, 3)
>>> m
Matrix([
[1, 0, 0],
[0, 2, 0],
[0, 0, 3]])
>>> m.is_diagonal()
True
See Also
========
is_lower
is_upper
sympy.matrices.matrixbase.MatrixCommon.is_diagonalizable
diagonalize
"""
return self._eval_is_diagonal()
@property
def is_weakly_diagonally_dominant(self):
r"""Tests if the matrix is row weakly diagonally dominant.
Explanation
===========
A $n, n$ matrix $A$ is row weakly diagonally dominant if
.. math::
\left|A_{i, i}\right| \ge \sum_{j = 0, j \neq i}^{n-1}
\left|A_{i, j}\right| \quad {\text{for all }}
i \in \{ 0, ..., n-1 \}
Examples
========
>>> from sympy import Matrix
>>> A = Matrix([[3, -2, 1], [1, -3, 2], [-1, 2, 4]])
>>> A.is_weakly_diagonally_dominant
True
>>> A = Matrix([[-2, 2, 1], [1, 3, 2], [1, -2, 0]])
>>> A.is_weakly_diagonally_dominant
False
>>> A = Matrix([[-4, 2, 1], [1, 6, 2], [1, -2, 5]])
>>> A.is_weakly_diagonally_dominant
True
Notes
=====
If you want to test whether a matrix is column diagonally
dominant, you can apply the test after transposing the matrix.
"""
if not self.is_square:
return False
rows, cols = self.shape
def test_row(i):
summation = self.zero
for j in range(cols):
if i != j:
summation += Abs(self[i, j])
return (Abs(self[i, i]) - summation).is_nonnegative
return fuzzy_and(test_row(i) for i in range(rows))
@property
def is_strongly_diagonally_dominant(self):
r"""Tests if the matrix is row strongly diagonally dominant.
Explanation
===========
A $n, n$ matrix $A$ is row strongly diagonally dominant if
.. math::
\left|A_{i, i}\right| > \sum_{j = 0, j \neq i}^{n-1}
\left|A_{i, j}\right| \quad {\text{for all }}
i \in \{ 0, ..., n-1 \}
Examples
========
>>> from sympy import Matrix
>>> A = Matrix([[3, -2, 1], [1, -3, 2], [-1, 2, 4]])
>>> A.is_strongly_diagonally_dominant
False
>>> A = Matrix([[-2, 2, 1], [1, 3, 2], [1, -2, 0]])
>>> A.is_strongly_diagonally_dominant
False
>>> A = Matrix([[-4, 2, 1], [1, 6, 2], [1, -2, 5]])
>>> A.is_strongly_diagonally_dominant
True
Notes
=====
If you want to test whether a matrix is column diagonally
dominant, you can apply the test after transposing the matrix.
"""
if not self.is_square:
return False
rows, cols = self.shape
def test_row(i):
summation = self.zero
for j in range(cols):
if i != j:
summation += Abs(self[i, j])
return (Abs(self[i, i]) - summation).is_positive
return fuzzy_and(test_row(i) for i in range(rows))
@property
def is_hermitian(self):
"""Checks if the matrix is Hermitian.
In a Hermitian matrix element i,j is the complex conjugate of
element j,i.
Examples
========
>>> from sympy import Matrix
>>> from sympy import I
>>> from sympy.abc import x
>>> a = Matrix([[1, I], [-I, 1]])
>>> a
Matrix([
[ 1, I],
[-I, 1]])
>>> a.is_hermitian
True
>>> a[0, 0] = 2*I
>>> a.is_hermitian
False
>>> a[0, 0] = x
>>> a.is_hermitian
>>> a[0, 1] = a[1, 0]*I
>>> a.is_hermitian
False
"""
if not self.is_square:
return False
return self._eval_is_matrix_hermitian(_simplify)
@property
def is_Identity(self) -> FuzzyBool:
if not self.is_square:
return False
return self._eval_is_Identity()
@property
def is_lower_hessenberg(self):
r"""Checks if the matrix is in the lower-Hessenberg form.
The lower hessenberg matrix has zero entries
above the first superdiagonal.
Examples
========
>>> from sympy import Matrix
>>> a = Matrix([[1, 2, 0, 0], [5, 2, 3, 0], [3, 4, 3, 7], [5, 6, 1, 1]])
>>> a
Matrix([
[1, 2, 0, 0],
[5, 2, 3, 0],
[3, 4, 3, 7],
[5, 6, 1, 1]])
>>> a.is_lower_hessenberg
True
See Also
========
is_upper_hessenberg
is_lower
"""
return self._eval_is_lower_hessenberg()
@property
def is_lower(self):
"""Check if matrix is a lower triangular matrix. True can be returned
even if the matrix is not square.
Examples
========
>>> from sympy import Matrix
>>> m = Matrix(2, 2, [1, 0, 0, 1])
>>> m
Matrix([
[1, 0],
[0, 1]])
>>> m.is_lower
True
>>> m = Matrix(4, 3, [0, 0, 0, 2, 0, 0, 1, 4, 0, 6, 6, 5])
>>> m
Matrix([
[0, 0, 0],
[2, 0, 0],
[1, 4, 0],
[6, 6, 5]])
>>> m.is_lower
True
>>> from sympy.abc import x, y
>>> m = Matrix(2, 2, [x**2 + y, y**2 + x, 0, x + y])
>>> m
Matrix([
[x**2 + y, x + y**2],
[ 0, x + y]])
>>> m.is_lower
False
See Also
========
is_upper
is_diagonal
is_lower_hessenberg
"""
return self._eval_is_lower()
@property
def is_square(self):
"""Checks if a matrix is square.
A matrix is square if the number of rows equals the number of columns.
The empty matrix is square by definition, since the number of rows and
the number of columns are both zero.
Examples
========
>>> from sympy import Matrix
>>> a = Matrix([[1, 2, 3], [4, 5, 6]])
>>> b = Matrix([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
>>> c = Matrix([])
>>> a.is_square
False
>>> b.is_square
True
>>> c.is_square
True
"""
return self.rows == self.cols
def is_symbolic(self):
"""Checks if any elements contain Symbols.
Examples
========
>>> from sympy import Matrix
>>> from sympy.abc import x, y
>>> M = Matrix([[x, y], [1, 0]])
>>> M.is_symbolic()
True
"""
return self._eval_is_symbolic()
def is_symmetric(self, simplify=True):
"""Check if matrix is symmetric matrix,
that is square matrix and is equal to its transpose.
By default, simplifications occur before testing symmetry.
They can be skipped using 'simplify=False'; while speeding things a bit,
this may however induce false negatives.
Examples
========
>>> from sympy import Matrix
>>> m = Matrix(2, 2, [0, 1, 1, 2])
>>> m
Matrix([
[0, 1],
[1, 2]])
>>> m.is_symmetric()
True
>>> m = Matrix(2, 2, [0, 1, 2, 0])
>>> m
Matrix([
[0, 1],
[2, 0]])
>>> m.is_symmetric()
False
>>> m = Matrix(2, 3, [0, 0, 0, 0, 0, 0])
>>> m
Matrix([
[0, 0, 0],
[0, 0, 0]])
>>> m.is_symmetric()
False
>>> from sympy.abc import x, y
>>> m = Matrix(3, 3, [1, x**2 + 2*x + 1, y, (x + 1)**2, 2, 0, y, 0, 3])
>>> m
Matrix([
[ 1, x**2 + 2*x + 1, y],
[(x + 1)**2, 2, 0],
[ y, 0, 3]])
>>> m.is_symmetric()
True
If the matrix is already simplified, you may speed-up is_symmetric()
test by using 'simplify=False'.
>>> bool(m.is_symmetric(simplify=False))
False
>>> m1 = m.expand()
>>> m1.is_symmetric(simplify=False)
True
"""
simpfunc = simplify
if not isfunction(simplify):
simpfunc = _simplify if simplify else lambda x: x
if not self.is_square:
return False
return self._eval_is_symmetric(simpfunc)
@property
def is_upper_hessenberg(self):
"""Checks if the matrix is the upper-Hessenberg form.
The upper hessenberg matrix has zero entries
below the first subdiagonal.
Examples
========
>>> from sympy import Matrix
>>> a = Matrix([[1, 4, 2, 3], [3, 4, 1, 7], [0, 2, 3, 4], [0, 0, 1, 3]])
>>> a
Matrix([
[1, 4, 2, 3],
[3, 4, 1, 7],
[0, 2, 3, 4],
[0, 0, 1, 3]])
>>> a.is_upper_hessenberg
True
See Also
========
is_lower_hessenberg
is_upper
"""
return self._eval_is_upper_hessenberg()
@property
def is_upper(self):
"""Check if matrix is an upper triangular matrix. True can be returned
even if the matrix is not square.
Examples
========
>>> from sympy import Matrix
>>> m = Matrix(2, 2, [1, 0, 0, 1])
>>> m
Matrix([
[1, 0],
[0, 1]])
>>> m.is_upper
True
>>> m = Matrix(4, 3, [5, 1, 9, 0, 4, 6, 0, 0, 5, 0, 0, 0])
>>> m
Matrix([
[5, 1, 9],
[0, 4, 6],
[0, 0, 5],
[0, 0, 0]])
>>> m.is_upper
True
>>> m = Matrix(2, 3, [4, 2, 5, 6, 1, 1])
>>> m
Matrix([
[4, 2, 5],
[6, 1, 1]])
>>> m.is_upper
False
See Also
========
is_lower
is_diagonal
is_upper_hessenberg
"""
return all(self[i, j].is_zero
for i in range(1, self.rows)
for j in range(min(i, self.cols)))
@property
def is_zero_matrix(self):
"""Checks if a matrix is a zero matrix.
A matrix is zero if every element is zero. A matrix need not be square
to be considered zero. The empty matrix is zero by the principle of
vacuous truth. For a matrix that may or may not be zero (e.g.
contains a symbol), this will be None
Examples
========
>>> from sympy import Matrix, zeros
>>> from sympy.abc import x
>>> a = Matrix([[0, 0], [0, 0]])
>>> b = zeros(3, 4)
>>> c = Matrix([[0, 1], [0, 0]])
>>> d = Matrix([])
>>> e = Matrix([[x, 0], [0, 0]])
>>> a.is_zero_matrix
True
>>> b.is_zero_matrix
True
>>> c.is_zero_matrix
False
>>> d.is_zero_matrix
True
>>> e.is_zero_matrix
"""
return self._eval_is_zero_matrix()
def values(self):
"""Return non-zero values of self."""
return self._eval_values()
class MatrixOperations(MatrixRequired):
"""Provides basic matrix shape and elementwise
operations. Should not be instantiated directly."""
def _eval_adjoint(self):
return self.transpose().conjugate()
def _eval_applyfunc(self, f):
out = self._new(self.rows, self.cols, [f(x) for x in self])
return out
def _eval_as_real_imag(self): # type: ignore
return (self.applyfunc(re), self.applyfunc(im))
def _eval_conjugate(self):
return self.applyfunc(lambda x: x.conjugate())
def _eval_permute_cols(self, perm):
# apply the permutation to a list
mapping = list(perm)
def entry(i, j):
return self[i, mapping[j]]
return self._new(self.rows, self.cols, entry)
def _eval_permute_rows(self, perm):
# apply the permutation to a list
mapping = list(perm)
def entry(i, j):
return self[mapping[i], j]
return self._new(self.rows, self.cols, entry)
def _eval_trace(self):
return sum(self[i, i] for i in range(self.rows))
def _eval_transpose(self):
return self._new(self.cols, self.rows, lambda i, j: self[j, i])
def adjoint(self):
"""Conjugate transpose or Hermitian conjugation."""
return self._eval_adjoint()
def applyfunc(self, f):
"""Apply a function to each element of the matrix.
Examples
========
>>> from sympy import Matrix
>>> m = Matrix(2, 2, lambda i, j: i*2+j)
>>> m
Matrix([
[0, 1],
[2, 3]])
>>> m.applyfunc(lambda i: 2*i)
Matrix([
[0, 2],
[4, 6]])
"""
if not callable(f):
raise TypeError("`f` must be callable.")
return self._eval_applyfunc(f)
def as_real_imag(self, deep=True, **hints):
"""Returns a tuple containing the (real, imaginary) part of matrix."""
# XXX: Ignoring deep and hints...
return self._eval_as_real_imag()
def conjugate(self):
"""Return the by-element conjugation.
Examples
========
>>> from sympy import SparseMatrix, I
>>> a = SparseMatrix(((1, 2 + I), (3, 4), (I, -I)))
>>> a
Matrix([
[1, 2 + I],
[3, 4],
[I, -I]])
>>> a.C
Matrix([
[ 1, 2 - I],
[ 3, 4],
[-I, I]])
See Also
========
transpose: Matrix transposition
H: Hermite conjugation
sympy.matrices.matrixbase.MatrixBase.D: Dirac conjugation
"""
return self._eval_conjugate()
def doit(self, **hints):
return self.applyfunc(lambda x: x.doit(**hints))
def evalf(self, n=15, subs=None, maxn=100, chop=False, strict=False, quad=None, verbose=False):
"""Apply evalf() to each element of self."""
options = {'subs':subs, 'maxn':maxn, 'chop':chop, 'strict':strict,
'quad':quad, 'verbose':verbose}
return self.applyfunc(lambda i: i.evalf(n, **options))
def expand(self, deep=True, modulus=None, power_base=True, power_exp=True,
mul=True, log=True, multinomial=True, basic=True, **hints):
"""Apply core.function.expand to each entry of the matrix.
Examples
========
>>> from sympy.abc import x
>>> from sympy import Matrix
>>> Matrix(1, 1, [x*(x+1)])
Matrix([[x*(x + 1)]])
>>> _.expand()
Matrix([[x**2 + x]])
"""
return self.applyfunc(lambda x: x.expand(
deep, modulus, power_base, power_exp, mul, log, multinomial, basic,
**hints))
@property
def H(self):
"""Return Hermite conjugate.
Examples
========
>>> from sympy import Matrix, I
>>> m = Matrix((0, 1 + I, 2, 3))
>>> m
Matrix([
[ 0],
[1 + I],
[ 2],
[ 3]])
>>> m.H
Matrix([[0, 1 - I, 2, 3]])
See Also
========
conjugate: By-element conjugation
sympy.matrices.matrixbase.MatrixBase.D: Dirac conjugation
"""
return self.T.C
def permute(self, perm, orientation='rows', direction='forward'):
r"""Permute the rows or columns of a matrix by the given list of
swaps.
Parameters
==========
perm : Permutation, list, or list of lists
A representation for the permutation.
If it is ``Permutation``, it is used directly with some
resizing with respect to the matrix size.
If it is specified as list of lists,
(e.g., ``[[0, 1], [0, 2]]``), then the permutation is formed
from applying the product of cycles. The direction how the
cyclic product is applied is described in below.
If it is specified as a list, the list should represent
an array form of a permutation. (e.g., ``[1, 2, 0]``) which
would would form the swapping function
`0 \mapsto 1, 1 \mapsto 2, 2\mapsto 0`.
orientation : 'rows', 'cols'
A flag to control whether to permute the rows or the columns
direction : 'forward', 'backward'
A flag to control whether to apply the permutations from
the start of the list first, or from the back of the list
first.
For example, if the permutation specification is
``[[0, 1], [0, 2]]``,
If the flag is set to ``'forward'``, the cycle would be
formed as `0 \mapsto 2, 2 \mapsto 1, 1 \mapsto 0`.
If the flag is set to ``'backward'``, the cycle would be
formed as `0 \mapsto 1, 1 \mapsto 2, 2 \mapsto 0`.
If the argument ``perm`` is not in a form of list of lists,
this flag takes no effect.
Examples
========
>>> from sympy import eye
>>> M = eye(3)
>>> M.permute([[0, 1], [0, 2]], orientation='rows', direction='forward')
Matrix([
[0, 0, 1],
[1, 0, 0],
[0, 1, 0]])
>>> from sympy import eye
>>> M = eye(3)
>>> M.permute([[0, 1], [0, 2]], orientation='rows', direction='backward')
Matrix([
[0, 1, 0],
[0, 0, 1],
[1, 0, 0]])
Notes
=====
If a bijective function
`\sigma : \mathbb{N}_0 \rightarrow \mathbb{N}_0` denotes the
permutation.
If the matrix `A` is the matrix to permute, represented as
a horizontal or a vertical stack of vectors:
.. math::
A =
\begin{bmatrix}
a_0 \\ a_1 \\ \vdots \\ a_{n-1}
\end{bmatrix} =
\begin{bmatrix}
\alpha_0 & \alpha_1 & \cdots & \alpha_{n-1}
\end{bmatrix}
If the matrix `B` is the result, the permutation of matrix rows
is defined as:
.. math::
B := \begin{bmatrix}
a_{\sigma(0)} \\ a_{\sigma(1)} \\ \vdots \\ a_{\sigma(n-1)}
\end{bmatrix}
And the permutation of matrix columns is defined as:
.. math::
B := \begin{bmatrix}
\alpha_{\sigma(0)} & \alpha_{\sigma(1)} &
\cdots & \alpha_{\sigma(n-1)}
\end{bmatrix}
"""
from sympy.combinatorics import Permutation
# allow british variants and `columns`
if direction == 'forwards':
direction = 'forward'
if direction == 'backwards':
direction = 'backward'
if orientation == 'columns':
orientation = 'cols'
if direction not in ('forward', 'backward'):
raise TypeError("direction='{}' is an invalid kwarg. "
"Try 'forward' or 'backward'".format(direction))
if orientation not in ('rows', 'cols'):
raise TypeError("orientation='{}' is an invalid kwarg. "
"Try 'rows' or 'cols'".format(orientation))
if not isinstance(perm, (Permutation, Iterable)):
raise ValueError(
"{} must be a list, a list of lists, "
"or a SymPy permutation object.".format(perm))
# ensure all swaps are in range
max_index = self.rows if orientation == 'rows' else self.cols
if not all(0 <= t <= max_index for t in flatten(list(perm))):
raise IndexError("`swap` indices out of range.")
if perm and not isinstance(perm, Permutation) and \
isinstance(perm[0], Iterable):
if direction == 'forward':
perm = list(reversed(perm))
perm = Permutation(perm, size=max_index+1)
else:
perm = Permutation(perm, size=max_index+1)
if orientation == 'rows':
return self._eval_permute_rows(perm)
if orientation == 'cols':
return self._eval_permute_cols(perm)
def permute_cols(self, swaps, direction='forward'):
"""Alias for
``self.permute(swaps, orientation='cols', direction=direction)``
See Also
========
permute
"""
return self.permute(swaps, orientation='cols', direction=direction)
def permute_rows(self, swaps, direction='forward'):
"""Alias for
``self.permute(swaps, orientation='rows', direction=direction)``
See Also
========
permute
"""
return self.permute(swaps, orientation='rows', direction=direction)
def refine(self, assumptions=True):
"""Apply refine to each element of the matrix.
Examples
========
>>> from sympy import Symbol, Matrix, Abs, sqrt, Q
>>> x = Symbol('x')
>>> Matrix([[Abs(x)**2, sqrt(x**2)],[sqrt(x**2), Abs(x)**2]])
Matrix([
[ Abs(x)**2, sqrt(x**2)],
[sqrt(x**2), Abs(x)**2]])
>>> _.refine(Q.real(x))
Matrix([
[ x**2, Abs(x)],
[Abs(x), x**2]])
"""
return self.applyfunc(lambda x: refine(x, assumptions))
def replace(self, F, G, map=False, simultaneous=True, exact=None):
"""Replaces Function F in Matrix entries with Function G.
Examples
========
>>> from sympy import symbols, Function, Matrix
>>> F, G = symbols('F, G', cls=Function)
>>> M = Matrix(2, 2, lambda i, j: F(i+j)) ; M
Matrix([
[F(0), F(1)],
[F(1), F(2)]])
>>> N = M.replace(F,G)
>>> N
Matrix([
[G(0), G(1)],
[G(1), G(2)]])
"""
return self.applyfunc(
lambda x: x.replace(F, G, map=map, simultaneous=simultaneous, exact=exact))
def rot90(self, k=1):
"""Rotates Matrix by 90 degrees
Parameters
==========
k : int
Specifies how many times the matrix is rotated by 90 degrees
(clockwise when positive, counter-clockwise when negative).
Examples
========
>>> from sympy import Matrix, symbols
>>> A = Matrix(2, 2, symbols('a:d'))
>>> A
Matrix([
[a, b],
[c, d]])
Rotating the matrix clockwise one time:
>>> A.rot90(1)
Matrix([
[c, a],
[d, b]])
Rotating the matrix anticlockwise two times:
>>> A.rot90(-2)
Matrix([
[d, c],
[b, a]])
"""
mod = k%4
if mod == 0:
return self
if mod == 1:
return self[::-1, ::].T
if mod == 2:
return self[::-1, ::-1]
if mod == 3:
return self[::, ::-1].T
def simplify(self, **kwargs):
"""Apply simplify to each element of the matrix.
Examples
========
>>> from sympy.abc import x, y
>>> from sympy import SparseMatrix, sin, cos
>>> SparseMatrix(1, 1, [x*sin(y)**2 + x*cos(y)**2])
Matrix([[x*sin(y)**2 + x*cos(y)**2]])
>>> _.simplify()
Matrix([[x]])
"""
return self.applyfunc(lambda x: x.simplify(**kwargs))
def subs(self, *args, **kwargs): # should mirror core.basic.subs
"""Return a new matrix with subs applied to each entry.
Examples
========
>>> from sympy.abc import x, y
>>> from sympy import SparseMatrix, Matrix
>>> SparseMatrix(1, 1, [x])
Matrix([[x]])
>>> _.subs(x, y)
Matrix([[y]])
>>> Matrix(_).subs(y, x)
Matrix([[x]])
"""
if len(args) == 1 and not isinstance(args[0], (dict, set)) and iter(args[0]) and not is_sequence(args[0]):
args = (list(args[0]),)
return self.applyfunc(lambda x: x.subs(*args, **kwargs))
def trace(self):
"""
Returns the trace of a square matrix i.e. the sum of the
diagonal elements.
Examples
========
>>> from sympy import Matrix
>>> A = Matrix(2, 2, [1, 2, 3, 4])
>>> A.trace()
5
"""
if self.rows != self.cols:
raise NonSquareMatrixError()
return self._eval_trace()
def transpose(self):
"""
Returns the transpose of the matrix.
Examples
========
>>> from sympy import Matrix
>>> A = Matrix(2, 2, [1, 2, 3, 4])
>>> A.transpose()
Matrix([
[1, 3],
[2, 4]])
>>> from sympy import Matrix, I
>>> m=Matrix(((1, 2+I), (3, 4)))
>>> m
Matrix([
[1, 2 + I],
[3, 4]])
>>> m.transpose()
Matrix([
[ 1, 3],
[2 + I, 4]])
>>> m.T == m.transpose()
True
See Also
========
conjugate: By-element conjugation
"""
return self._eval_transpose()
@property
def T(self):
'''Matrix transposition'''
return self.transpose()
@property
def C(self):
'''By-element conjugation'''
return self.conjugate()
def n(self, *args, **kwargs):
"""Apply evalf() to each element of self."""
return self.evalf(*args, **kwargs)
def xreplace(self, rule): # should mirror core.basic.xreplace
"""Return a new matrix with xreplace applied to each entry.
Examples
========
>>> from sympy.abc import x, y
>>> from sympy import SparseMatrix, Matrix
>>> SparseMatrix(1, 1, [x])
Matrix([[x]])
>>> _.xreplace({x: y})
Matrix([[y]])
>>> Matrix(_).xreplace({y: x})
Matrix([[x]])
"""
return self.applyfunc(lambda x: x.xreplace(rule))
def _eval_simplify(self, **kwargs):
# XXX: We can't use self.simplify here as mutable subclasses will
# override simplify and have it return None
return MatrixOperations.simplify(self, **kwargs)
def _eval_trigsimp(self, **opts):
from sympy.simplify.trigsimp import trigsimp
return self.applyfunc(lambda x: trigsimp(x, **opts))
def upper_triangular(self, k=0):
"""Return the elements on and above the kth diagonal of a matrix.
If k is not specified then simply returns upper-triangular portion
of a matrix
Examples
========
>>> from sympy import ones
>>> A = ones(4)
>>> A.upper_triangular()
Matrix([
[1, 1, 1, 1],
[0, 1, 1, 1],
[0, 0, 1, 1],
[0, 0, 0, 1]])
>>> A.upper_triangular(2)
Matrix([
[0, 0, 1, 1],
[0, 0, 0, 1],
[0, 0, 0, 0],
[0, 0, 0, 0]])
>>> A.upper_triangular(-1)
Matrix([
[1, 1, 1, 1],
[1, 1, 1, 1],
[0, 1, 1, 1],
[0, 0, 1, 1]])
"""
def entry(i, j):
return self[i, j] if i + k <= j else self.zero
return self._new(self.rows, self.cols, entry)
def lower_triangular(self, k=0):
"""Return the elements on and below the kth diagonal of a matrix.
If k is not specified then simply returns lower-triangular portion
of a matrix
Examples
========
>>> from sympy import ones
>>> A = ones(4)
>>> A.lower_triangular()
Matrix([
[1, 0, 0, 0],
[1, 1, 0, 0],
[1, 1, 1, 0],
[1, 1, 1, 1]])
>>> A.lower_triangular(-2)
Matrix([
[0, 0, 0, 0],
[0, 0, 0, 0],
[1, 0, 0, 0],
[1, 1, 0, 0]])
>>> A.lower_triangular(1)
Matrix([
[1, 1, 0, 0],
[1, 1, 1, 0],
[1, 1, 1, 1],
[1, 1, 1, 1]])
"""
def entry(i, j):
return self[i, j] if i + k >= j else self.zero
return self._new(self.rows, self.cols, entry)
class MatrixArithmetic(MatrixRequired):
"""Provides basic matrix arithmetic operations.
Should not be instantiated directly."""
_op_priority = 10.01
def _eval_Abs(self):
return self._new(self.rows, self.cols, lambda i, j: Abs(self[i, j]))
def _eval_add(self, other):
return self._new(self.rows, self.cols,
lambda i, j: self[i, j] + other[i, j])
def _eval_matrix_mul(self, other):
def entry(i, j):
vec = [self[i,k]*other[k,j] for k in range(self.cols)]
try:
return Add(*vec)
except (TypeError, SympifyError):
# Some matrices don't work with `sum` or `Add`
# They don't work with `sum` because `sum` tries to add `0`
# Fall back to a safe way to multiply if the `Add` fails.
return reduce(lambda a, b: a + b, vec)
return self._new(self.rows, other.cols, entry)
def _eval_matrix_mul_elementwise(self, other):
return self._new(self.rows, self.cols, lambda i, j: self[i,j]*other[i,j])
def _eval_matrix_rmul(self, other):
def entry(i, j):
return sum(other[i,k]*self[k,j] for k in range(other.cols))
return self._new(other.rows, self.cols, entry)
def _eval_pow_by_recursion(self, num):
if num == 1:
return self
if num % 2 == 1:
a, b = self, self._eval_pow_by_recursion(num - 1)
else:
a = b = self._eval_pow_by_recursion(num // 2)
return a.multiply(b)
def _eval_pow_by_cayley(self, exp):
from sympy.discrete.recurrences import linrec_coeffs
row = self.shape[0]
p = self.charpoly()
coeffs = (-p).all_coeffs()[1:]
coeffs = linrec_coeffs(coeffs, exp)
new_mat = self.eye(row)
ans = self.zeros(row)
for i in range(row):
ans += coeffs[i]*new_mat
new_mat *= self
return ans
def _eval_pow_by_recursion_dotprodsimp(self, num, prevsimp=None):
if prevsimp is None:
prevsimp = [True]*len(self)
if num == 1:
return self
if num % 2 == 1:
a, b = self, self._eval_pow_by_recursion_dotprodsimp(num - 1,
prevsimp=prevsimp)
else:
a = b = self._eval_pow_by_recursion_dotprodsimp(num // 2,
prevsimp=prevsimp)
m = a.multiply(b, dotprodsimp=False)
lenm = len(m)
elems = [None]*lenm
for i in range(lenm):
if prevsimp[i]:
elems[i], prevsimp[i] = _dotprodsimp(m[i], withsimp=True)
else:
elems[i] = m[i]
return m._new(m.rows, m.cols, elems)
def _eval_scalar_mul(self, other):
return self._new(self.rows, self.cols, lambda i, j: self[i,j]*other)
def _eval_scalar_rmul(self, other):
return self._new(self.rows, self.cols, lambda i, j: other*self[i,j])
def _eval_Mod(self, other):
return self._new(self.rows, self.cols, lambda i, j: Mod(self[i, j], other))
# Python arithmetic functions
def __abs__(self):
"""Returns a new matrix with entry-wise absolute values."""
return self._eval_Abs()
@call_highest_priority('__radd__')
def __add__(self, other):
"""Return self + other, raising ShapeError if shapes do not match."""
if isinstance(other, NDimArray): # Matrix and array addition is currently not implemented
return NotImplemented
other = _matrixify(other)
# matrix-like objects can have shapes. This is
# our first sanity check.
if hasattr(other, 'shape'):
if self.shape != other.shape:
raise ShapeError("Matrix size mismatch: %s + %s" % (
self.shape, other.shape))
# honest SymPy matrices defer to their class's routine
if getattr(other, 'is_Matrix', False):
# call the highest-priority class's _eval_add
a, b = self, other
if a.__class__ != classof(a, b):
b, a = a, b
return a._eval_add(b)
# Matrix-like objects can be passed to CommonMatrix routines directly.
if getattr(other, 'is_MatrixLike', False):
return MatrixArithmetic._eval_add(self, other)
raise TypeError('cannot add %s and %s' % (type(self), type(other)))
@call_highest_priority('__rtruediv__')
def __truediv__(self, other):
return self * (self.one / other)
@call_highest_priority('__rmatmul__')
def __matmul__(self, other):
other = _matrixify(other)
if not getattr(other, 'is_Matrix', False) and not getattr(other, 'is_MatrixLike', False):
return NotImplemented
return self.__mul__(other)
def __mod__(self, other):
return self.applyfunc(lambda x: x % other)
@call_highest_priority('__rmul__')
def __mul__(self, other):
"""Return self*other where other is either a scalar or a matrix
of compatible dimensions.
Examples
========
>>> from sympy import Matrix
>>> A = Matrix([[1, 2, 3], [4, 5, 6]])
>>> 2*A == A*2 == Matrix([[2, 4, 6], [8, 10, 12]])
True
>>> B = Matrix([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
>>> A*B
Matrix([
[30, 36, 42],
[66, 81, 96]])
>>> B*A
Traceback (most recent call last):
...
ShapeError: Matrices size mismatch.
>>>
See Also
========
matrix_multiply_elementwise
"""
return self.multiply(other)
def multiply(self, other, dotprodsimp=None):
"""Same as __mul__() but with optional simplification.
Parameters
==========
dotprodsimp : bool, optional
Specifies whether intermediate term algebraic simplification is used
during matrix multiplications to control expression blowup and thus
speed up calculation. Default is off.
"""
isimpbool = _get_intermediate_simp_bool(False, dotprodsimp)
other = _matrixify(other)
# matrix-like objects can have shapes. This is
# our first sanity check. Double check other is not explicitly not a Matrix.
if (hasattr(other, 'shape') and len(other.shape) == 2 and
(getattr(other, 'is_Matrix', True) or
getattr(other, 'is_MatrixLike', True))):
if self.shape[1] != other.shape[0]:
raise ShapeError("Matrix size mismatch: %s * %s." % (
self.shape, other.shape))
# honest SymPy matrices defer to their class's routine
if getattr(other, 'is_Matrix', False):
m = self._eval_matrix_mul(other)
if isimpbool:
return m._new(m.rows, m.cols, [_dotprodsimp(e) for e in m])
return m
# Matrix-like objects can be passed to CommonMatrix routines directly.
if getattr(other, 'is_MatrixLike', False):
return MatrixArithmetic._eval_matrix_mul(self, other)
# if 'other' is not iterable then scalar multiplication.
if not isinstance(other, Iterable):
try:
return self._eval_scalar_mul(other)
except TypeError:
pass
return NotImplemented
def multiply_elementwise(self, other):
"""Return the Hadamard product (elementwise product) of A and B
Examples
========
>>> from sympy import Matrix
>>> A = Matrix([[0, 1, 2], [3, 4, 5]])
>>> B = Matrix([[1, 10, 100], [100, 10, 1]])
>>> A.multiply_elementwise(B)
Matrix([
[ 0, 10, 200],
[300, 40, 5]])
See Also
========
sympy.matrices.matrixbase.MatrixBase.cross
sympy.matrices.matrixbase.MatrixBase.dot
multiply
"""
if self.shape != other.shape:
raise ShapeError("Matrix shapes must agree {} != {}".format(self.shape, other.shape))
return self._eval_matrix_mul_elementwise(other)
def __neg__(self):
return self._eval_scalar_mul(-1)
@call_highest_priority('__rpow__')
def __pow__(self, exp):
"""Return self**exp a scalar or symbol."""
return self.pow(exp)
def pow(self, exp, method=None):
r"""Return self**exp a scalar or symbol.
Parameters
==========
method : multiply, mulsimp, jordan, cayley
If multiply then it returns exponentiation using recursion.
If jordan then Jordan form exponentiation will be used.
If cayley then the exponentiation is done using Cayley-Hamilton
theorem.
If mulsimp then the exponentiation is done using recursion
with dotprodsimp. This specifies whether intermediate term
algebraic simplification is used during naive matrix power to
control expression blowup and thus speed up calculation.
If None, then it heuristically decides which method to use.
"""
if method is not None and method not in ['multiply', 'mulsimp', 'jordan', 'cayley']:
raise TypeError('No such method')
if self.rows != self.cols:
raise NonSquareMatrixError()
a = self
jordan_pow = getattr(a, '_matrix_pow_by_jordan_blocks', None)
exp = sympify(exp)
if exp.is_zero:
return a._new(a.rows, a.cols, lambda i, j: int(i == j))
if exp == 1:
return a
diagonal = getattr(a, 'is_diagonal', None)
if diagonal is not None and diagonal():
return a._new(a.rows, a.cols, lambda i, j: a[i,j]**exp if i == j else 0)
if exp.is_Number and exp % 1 == 0:
if a.rows == 1:
return a._new([[a[0]**exp]])
if exp < 0:
exp = -exp
a = a.inv()
# When certain conditions are met,
# Jordan block algorithm is faster than
# computation by recursion.
if method == 'jordan':
try:
return jordan_pow(exp)
except MatrixError:
if method == 'jordan':
raise
elif method == 'cayley':
if not exp.is_Number or exp % 1 != 0:
raise ValueError("cayley method is only valid for integer powers")
return a._eval_pow_by_cayley(exp)
elif method == "mulsimp":
if not exp.is_Number or exp % 1 != 0:
raise ValueError("mulsimp method is only valid for integer powers")
return a._eval_pow_by_recursion_dotprodsimp(exp)
elif method == "multiply":
if not exp.is_Number or exp % 1 != 0:
raise ValueError("multiply method is only valid for integer powers")
return a._eval_pow_by_recursion(exp)
elif method is None and exp.is_Number and exp % 1 == 0:
if exp.is_Float:
exp = Integer(exp)
# Decide heuristically which method to apply
if a.rows == 2 and exp > 100000:
return jordan_pow(exp)
elif _get_intermediate_simp_bool(True, None):
return a._eval_pow_by_recursion_dotprodsimp(exp)
elif exp > 10000:
return a._eval_pow_by_cayley(exp)
else:
return a._eval_pow_by_recursion(exp)
if jordan_pow:
try:
return jordan_pow(exp)
except NonInvertibleMatrixError:
# Raised by jordan_pow on zero determinant matrix unless exp is
# definitely known to be a non-negative integer.
# Here we raise if n is definitely not a non-negative integer
# but otherwise we can leave this as an unevaluated MatPow.
if exp.is_integer is False or exp.is_nonnegative is False:
raise
from sympy.matrices.expressions import MatPow
return MatPow(a, exp)
@call_highest_priority('__add__')
def __radd__(self, other):
return self + other
@call_highest_priority('__matmul__')
def __rmatmul__(self, other):
other = _matrixify(other)
if not getattr(other, 'is_Matrix', False) and not getattr(other, 'is_MatrixLike', False):
return NotImplemented
return self.__rmul__(other)
@call_highest_priority('__mul__')
def __rmul__(self, other):
return self.rmultiply(other)
def rmultiply(self, other, dotprodsimp=None):
"""Same as __rmul__() but with optional simplification.
Parameters
==========
dotprodsimp : bool, optional
Specifies whether intermediate term algebraic simplification is used
during matrix multiplications to control expression blowup and thus
speed up calculation. Default is off.
"""
isimpbool = _get_intermediate_simp_bool(False, dotprodsimp)
other = _matrixify(other)
# matrix-like objects can have shapes. This is
# our first sanity check. Double check other is not explicitly not a Matrix.
if (hasattr(other, 'shape') and len(other.shape) == 2 and
(getattr(other, 'is_Matrix', True) or
getattr(other, 'is_MatrixLike', True))):
if self.shape[0] != other.shape[1]:
raise ShapeError("Matrix size mismatch.")
# honest SymPy matrices defer to their class's routine
if getattr(other, 'is_Matrix', False):
m = self._eval_matrix_rmul(other)
if isimpbool:
return m._new(m.rows, m.cols, [_dotprodsimp(e) for e in m])
return m
# Matrix-like objects can be passed to CommonMatrix routines directly.
if getattr(other, 'is_MatrixLike', False):
return MatrixArithmetic._eval_matrix_rmul(self, other)
# if 'other' is not iterable then scalar multiplication.
if not isinstance(other, Iterable):
try:
return self._eval_scalar_rmul(other)
except TypeError:
pass
return NotImplemented
@call_highest_priority('__sub__')
def __rsub__(self, a):
return (-self) + a
@call_highest_priority('__rsub__')
def __sub__(self, a):
return self + (-a)
class MatrixCommon(MatrixArithmetic, MatrixOperations, MatrixProperties,
MatrixSpecial, MatrixShaping):
"""All common matrix operations including basic arithmetic, shaping,
and special matrices like `zeros`, and `eye`."""
_diff_wrt = True # type: bool
class _MinimalMatrix:
"""Class providing the minimum functionality
for a matrix-like object and implementing every method
required for a `MatrixRequired`. This class does not have everything
needed to become a full-fledged SymPy object, but it will satisfy the
requirements of anything inheriting from `MatrixRequired`. If you wish
to make a specialized matrix type, make sure to implement these
methods and properties with the exception of `__init__` and `__repr__`
which are included for convenience."""
is_MatrixLike = True
_sympify = staticmethod(sympify)
_class_priority = 3
zero = S.Zero
one = S.One
is_Matrix = True
is_MatrixExpr = False
@classmethod
def _new(cls, *args, **kwargs):
return cls(*args, **kwargs)
def __init__(self, rows, cols=None, mat=None, copy=False):
if isfunction(mat):
# if we passed in a function, use that to populate the indices
mat = [mat(i, j) for i in range(rows) for j in range(cols)]
if cols is None and mat is None:
mat = rows
rows, cols = getattr(mat, 'shape', (rows, cols))
try:
# if we passed in a list of lists, flatten it and set the size
if cols is None and mat is None:
mat = rows
cols = len(mat[0])
rows = len(mat)
mat = [x for l in mat for x in l]
except (IndexError, TypeError):
pass
self.mat = tuple(self._sympify(x) for x in mat)
self.rows, self.cols = rows, cols
if self.rows is None or self.cols is None:
raise NotImplementedError("Cannot initialize matrix with given parameters")
def __getitem__(self, key):
def _normalize_slices(row_slice, col_slice):
"""Ensure that row_slice and col_slice do not have
`None` in their arguments. Any integers are converted
to slices of length 1"""
if not isinstance(row_slice, slice):
row_slice = slice(row_slice, row_slice + 1, None)
row_slice = slice(*row_slice.indices(self.rows))
if not isinstance(col_slice, slice):
col_slice = slice(col_slice, col_slice + 1, None)
col_slice = slice(*col_slice.indices(self.cols))
return (row_slice, col_slice)
def _coord_to_index(i, j):
"""Return the index in _mat corresponding
to the (i,j) position in the matrix. """
return i * self.cols + j
if isinstance(key, tuple):
i, j = key
if isinstance(i, slice) or isinstance(j, slice):
# if the coordinates are not slices, make them so
# and expand the slices so they don't contain `None`
i, j = _normalize_slices(i, j)
rowsList, colsList = list(range(self.rows))[i], \
list(range(self.cols))[j]
indices = (i * self.cols + j for i in rowsList for j in
colsList)
return self._new(len(rowsList), len(colsList),
[self.mat[i] for i in indices])
# if the key is a tuple of ints, change
# it to an array index
key = _coord_to_index(i, j)
return self.mat[key]
def __eq__(self, other):
try:
classof(self, other)
except TypeError:
return False
return (
self.shape == other.shape and list(self) == list(other))
def __len__(self):
return self.rows*self.cols
def __repr__(self):
return "_MinimalMatrix({}, {}, {})".format(self.rows, self.cols,
self.mat)
@property
def shape(self):
return (self.rows, self.cols)
class _CastableMatrix: # this is needed here ONLY FOR TESTS.
def as_mutable(self):
return self
def as_immutable(self):
return self
class _MatrixWrapper:
"""Wrapper class providing the minimum functionality for a matrix-like
object: .rows, .cols, .shape, indexability, and iterability. CommonMatrix
math operations should work on matrix-like objects. This one is intended for
matrix-like objects which use the same indexing format as SymPy with respect
to returning matrix elements instead of rows for non-tuple indexes.
"""
is_Matrix = False # needs to be here because of __getattr__
is_MatrixLike = True
def __init__(self, mat, shape):
self.mat = mat
self.shape = shape
self.rows, self.cols = shape
def __getitem__(self, key):
if isinstance(key, tuple):
return sympify(self.mat.__getitem__(key))
return sympify(self.mat.__getitem__((key // self.rows, key % self.cols)))
def __iter__(self): # supports numpy.matrix and numpy.array
mat = self.mat
cols = self.cols
return iter(sympify(mat[r, c]) for r in range(self.rows) for c in range(cols))
def _matrixify(mat):
"""If `mat` is a Matrix or is matrix-like,
return a Matrix or MatrixWrapper object. Otherwise
`mat` is passed through without modification."""
if getattr(mat, 'is_Matrix', False) or getattr(mat, 'is_MatrixLike', False):
return mat
if not(getattr(mat, 'is_Matrix', True) or getattr(mat, 'is_MatrixLike', True)):
return mat
shape = None
if hasattr(mat, 'shape'): # numpy, scipy.sparse
if len(mat.shape) == 2:
shape = mat.shape
elif hasattr(mat, 'rows') and hasattr(mat, 'cols'): # mpmath
shape = (mat.rows, mat.cols)
if shape:
return _MatrixWrapper(mat, shape)
return mat
def a2idx(j, n=None):
"""Return integer after making positive and validating against n."""
if not isinstance(j, int):
jindex = getattr(j, '__index__', None)
if jindex is not None:
j = jindex()
else:
raise IndexError("Invalid index a[%r]" % (j,))
if n is not None:
if j < 0:
j += n
if not (j >= 0 and j < n):
raise IndexError("Index out of range: a[%s]" % (j,))
return int(j)
def classof(A, B):
"""
Get the type of the result when combining matrices of different types.
Currently the strategy is that immutability is contagious.
Examples
========
>>> from sympy import Matrix, ImmutableMatrix
>>> from sympy.matrices.matrixbase import classof
>>> M = Matrix([[1, 2], [3, 4]]) # a Mutable Matrix
>>> IM = ImmutableMatrix([[1, 2], [3, 4]])
>>> classof(M, IM)
<class 'sympy.matrices.immutable.ImmutableDenseMatrix'>
"""
priority_A = getattr(A, '_class_priority', None)
priority_B = getattr(B, '_class_priority', None)
if None not in (priority_A, priority_B):
if A._class_priority > B._class_priority:
return A.__class__
else:
return B.__class__
try:
import numpy
except ImportError:
pass
else:
if isinstance(A, numpy.ndarray):
return B.__class__
if isinstance(B, numpy.ndarray):
return A.__class__
raise TypeError("Incompatible classes %s, %s" % (A.__class__, B.__class__))
PK ]ZZZ�,� �� �� sympy/matrices/decompositions.pyimport copy
from sympy.core import S
from sympy.core.function import expand_mul
from sympy.functions.elementary.miscellaneous import Min, sqrt
from sympy.functions.elementary.complexes import sign
from .exceptions import NonSquareMatrixError, NonPositiveDefiniteMatrixError
from .utilities import _get_intermediate_simp, _iszero
from .determinant import _find_reasonable_pivot_naive
def _rank_decomposition(M, iszerofunc=_iszero, simplify=False):
r"""Returns a pair of matrices (`C`, `F`) with matching rank
such that `A = C F`.
Parameters
==========
iszerofunc : Function, optional
A function used for detecting whether an element can
act as a pivot. ``lambda x: x.is_zero`` is used by default.
simplify : Bool or Function, optional
A function used to simplify elements when looking for a
pivot. By default SymPy's ``simplify`` is used.
Returns
=======
(C, F) : Matrices
`C` and `F` are full-rank matrices with rank as same as `A`,
whose product gives `A`.
See Notes for additional mathematical details.
Examples
========
>>> from sympy import Matrix
>>> A = Matrix([
... [1, 3, 1, 4],
... [2, 7, 3, 9],
... [1, 5, 3, 1],
... [1, 2, 0, 8]
... ])
>>> C, F = A.rank_decomposition()
>>> C
Matrix([
[1, 3, 4],
[2, 7, 9],
[1, 5, 1],
[1, 2, 8]])
>>> F
Matrix([
[1, 0, -2, 0],
[0, 1, 1, 0],
[0, 0, 0, 1]])
>>> C * F == A
True
Notes
=====
Obtaining `F`, an RREF of `A`, is equivalent to creating a
product
.. math::
E_n E_{n-1} ... E_1 A = F
where `E_n, E_{n-1}, \dots, E_1` are the elimination matrices or
permutation matrices equivalent to each row-reduction step.
The inverse of the same product of elimination matrices gives
`C`:
.. math::
C = \left(E_n E_{n-1} \dots E_1\right)^{-1}
It is not necessary, however, to actually compute the inverse:
the columns of `C` are those from the original matrix with the
same column indices as the indices of the pivot columns of `F`.
References
==========
.. [1] https://en.wikipedia.org/wiki/Rank_factorization
.. [2] Piziak, R.; Odell, P. L. (1 June 1999).
"Full Rank Factorization of Matrices".
Mathematics Magazine. 72 (3): 193. doi:10.2307/2690882
See Also
========
sympy.matrices.matrixbase.MatrixBase.rref
"""
F, pivot_cols = M.rref(simplify=simplify, iszerofunc=iszerofunc,
pivots=True)
rank = len(pivot_cols)
C = M.extract(range(M.rows), pivot_cols)
F = F[:rank, :]
return C, F
def _liupc(M):
"""Liu's algorithm, for pre-determination of the Elimination Tree of
the given matrix, used in row-based symbolic Cholesky factorization.
Examples
========
>>> from sympy import SparseMatrix
>>> S = SparseMatrix([
... [1, 0, 3, 2],
... [0, 0, 1, 0],
... [4, 0, 0, 5],
... [0, 6, 7, 0]])
>>> S.liupc()
([[0], [], [0], [1, 2]], [4, 3, 4, 4])
References
==========
.. [1] Symbolic Sparse Cholesky Factorization using Elimination Trees,
Jeroen Van Grondelle (1999)
https://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.39.7582
"""
# Algorithm 2.4, p 17 of reference
# get the indices of the elements that are non-zero on or below diag
R = [[] for r in range(M.rows)]
for r, c, _ in M.row_list():
if c <= r:
R[r].append(c)
inf = len(R) # nothing will be this large
parent = [inf]*M.rows
virtual = [inf]*M.rows
for r in range(M.rows):
for c in R[r][:-1]:
while virtual[c] < r:
t = virtual[c]
virtual[c] = r
c = t
if virtual[c] == inf:
parent[c] = virtual[c] = r
return R, parent
def _row_structure_symbolic_cholesky(M):
"""Symbolic cholesky factorization, for pre-determination of the
non-zero structure of the Cholesky factororization.
Examples
========
>>> from sympy import SparseMatrix
>>> S = SparseMatrix([
... [1, 0, 3, 2],
... [0, 0, 1, 0],
... [4, 0, 0, 5],
... [0, 6, 7, 0]])
>>> S.row_structure_symbolic_cholesky()
[[0], [], [0], [1, 2]]
References
==========
.. [1] Symbolic Sparse Cholesky Factorization using Elimination Trees,
Jeroen Van Grondelle (1999)
https://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.39.7582
"""
R, parent = M.liupc()
inf = len(R) # this acts as infinity
Lrow = copy.deepcopy(R)
for k in range(M.rows):
for j in R[k]:
while j != inf and j != k:
Lrow[k].append(j)
j = parent[j]
Lrow[k] = sorted(set(Lrow[k]))
return Lrow
def _cholesky(M, hermitian=True):
"""Returns the Cholesky-type decomposition L of a matrix A
such that L * L.H == A if hermitian flag is True,
or L * L.T == A if hermitian is False.
A must be a Hermitian positive-definite matrix if hermitian is True,
or a symmetric matrix if it is False.
Examples
========
>>> from sympy import Matrix
>>> A = Matrix(((25, 15, -5), (15, 18, 0), (-5, 0, 11)))
>>> A.cholesky()
Matrix([
[ 5, 0, 0],
[ 3, 3, 0],
[-1, 1, 3]])
>>> A.cholesky() * A.cholesky().T
Matrix([
[25, 15, -5],
[15, 18, 0],
[-5, 0, 11]])
The matrix can have complex entries:
>>> from sympy import I
>>> A = Matrix(((9, 3*I), (-3*I, 5)))
>>> A.cholesky()
Matrix([
[ 3, 0],
[-I, 2]])
>>> A.cholesky() * A.cholesky().H
Matrix([
[ 9, 3*I],
[-3*I, 5]])
Non-hermitian Cholesky-type decomposition may be useful when the
matrix is not positive-definite.
>>> A = Matrix([[1, 2], [2, 1]])
>>> L = A.cholesky(hermitian=False)
>>> L
Matrix([
[1, 0],
[2, sqrt(3)*I]])
>>> L*L.T == A
True
See Also
========
sympy.matrices.dense.DenseMatrix.LDLdecomposition
sympy.matrices.matrixbase.MatrixBase.LUdecomposition
QRdecomposition
"""
from .dense import MutableDenseMatrix
if not M.is_square:
raise NonSquareMatrixError("Matrix must be square.")
if hermitian and not M.is_hermitian:
raise ValueError("Matrix must be Hermitian.")
if not hermitian and not M.is_symmetric():
raise ValueError("Matrix must be symmetric.")
L = MutableDenseMatrix.zeros(M.rows, M.rows)
if hermitian:
for i in range(M.rows):
for j in range(i):
L[i, j] = ((1 / L[j, j])*(M[i, j] -
sum(L[i, k]*L[j, k].conjugate() for k in range(j))))
Lii2 = (M[i, i] -
sum(L[i, k]*L[i, k].conjugate() for k in range(i)))
if Lii2.is_positive is False:
raise NonPositiveDefiniteMatrixError(
"Matrix must be positive-definite")
L[i, i] = sqrt(Lii2)
else:
for i in range(M.rows):
for j in range(i):
L[i, j] = ((1 / L[j, j])*(M[i, j] -
sum(L[i, k]*L[j, k] for k in range(j))))
L[i, i] = sqrt(M[i, i] -
sum(L[i, k]**2 for k in range(i)))
return M._new(L)
def _cholesky_sparse(M, hermitian=True):
"""
Returns the Cholesky decomposition L of a matrix A
such that L * L.T = A
A must be a square, symmetric, positive-definite
and non-singular matrix
Examples
========
>>> from sympy import SparseMatrix
>>> A = SparseMatrix(((25,15,-5),(15,18,0),(-5,0,11)))
>>> A.cholesky()
Matrix([
[ 5, 0, 0],
[ 3, 3, 0],
[-1, 1, 3]])
>>> A.cholesky() * A.cholesky().T == A
True
The matrix can have complex entries:
>>> from sympy import I
>>> A = SparseMatrix(((9, 3*I), (-3*I, 5)))
>>> A.cholesky()
Matrix([
[ 3, 0],
[-I, 2]])
>>> A.cholesky() * A.cholesky().H
Matrix([
[ 9, 3*I],
[-3*I, 5]])
Non-hermitian Cholesky-type decomposition may be useful when the
matrix is not positive-definite.
>>> A = SparseMatrix([[1, 2], [2, 1]])
>>> L = A.cholesky(hermitian=False)
>>> L
Matrix([
[1, 0],
[2, sqrt(3)*I]])
>>> L*L.T == A
True
See Also
========
sympy.matrices.sparse.SparseMatrix.LDLdecomposition
sympy.matrices.matrixbase.MatrixBase.LUdecomposition
QRdecomposition
"""
from .dense import MutableDenseMatrix
if not M.is_square:
raise NonSquareMatrixError("Matrix must be square.")
if hermitian and not M.is_hermitian:
raise ValueError("Matrix must be Hermitian.")
if not hermitian and not M.is_symmetric():
raise ValueError("Matrix must be symmetric.")
dps = _get_intermediate_simp(expand_mul, expand_mul)
Crowstruc = M.row_structure_symbolic_cholesky()
C = MutableDenseMatrix.zeros(M.rows)
for i in range(len(Crowstruc)):
for j in Crowstruc[i]:
if i != j:
C[i, j] = M[i, j]
summ = 0
for p1 in Crowstruc[i]:
if p1 < j:
for p2 in Crowstruc[j]:
if p2 < j:
if p1 == p2:
if hermitian:
summ += C[i, p1]*C[j, p1].conjugate()
else:
summ += C[i, p1]*C[j, p1]
else:
break
else:
break
C[i, j] = dps((C[i, j] - summ) / C[j, j])
else: # i == j
C[j, j] = M[j, j]
summ = 0
for k in Crowstruc[j]:
if k < j:
if hermitian:
summ += C[j, k]*C[j, k].conjugate()
else:
summ += C[j, k]**2
else:
break
Cjj2 = dps(C[j, j] - summ)
if hermitian and Cjj2.is_positive is False:
raise NonPositiveDefiniteMatrixError(
"Matrix must be positive-definite")
C[j, j] = sqrt(Cjj2)
return M._new(C)
def _LDLdecomposition(M, hermitian=True):
"""Returns the LDL Decomposition (L, D) of matrix A,
such that L * D * L.H == A if hermitian flag is True, or
L * D * L.T == A if hermitian is False.
This method eliminates the use of square root.
Further this ensures that all the diagonal entries of L are 1.
A must be a Hermitian positive-definite matrix if hermitian is True,
or a symmetric matrix otherwise.
Examples
========
>>> from sympy import Matrix, eye
>>> A = Matrix(((25, 15, -5), (15, 18, 0), (-5, 0, 11)))
>>> L, D = A.LDLdecomposition()
>>> L
Matrix([
[ 1, 0, 0],
[ 3/5, 1, 0],
[-1/5, 1/3, 1]])
>>> D
Matrix([
[25, 0, 0],
[ 0, 9, 0],
[ 0, 0, 9]])
>>> L * D * L.T * A.inv() == eye(A.rows)
True
The matrix can have complex entries:
>>> from sympy import I
>>> A = Matrix(((9, 3*I), (-3*I, 5)))
>>> L, D = A.LDLdecomposition()
>>> L
Matrix([
[ 1, 0],
[-I/3, 1]])
>>> D
Matrix([
[9, 0],
[0, 4]])
>>> L*D*L.H == A
True
See Also
========
sympy.matrices.dense.DenseMatrix.cholesky
sympy.matrices.matrixbase.MatrixBase.LUdecomposition
QRdecomposition
"""
from .dense import MutableDenseMatrix
if not M.is_square:
raise NonSquareMatrixError("Matrix must be square.")
if hermitian and not M.is_hermitian:
raise ValueError("Matrix must be Hermitian.")
if not hermitian and not M.is_symmetric():
raise ValueError("Matrix must be symmetric.")
D = MutableDenseMatrix.zeros(M.rows, M.rows)
L = MutableDenseMatrix.eye(M.rows)
if hermitian:
for i in range(M.rows):
for j in range(i):
L[i, j] = (1 / D[j, j])*(M[i, j] - sum(
L[i, k]*L[j, k].conjugate()*D[k, k] for k in range(j)))
D[i, i] = (M[i, i] -
sum(L[i, k]*L[i, k].conjugate()*D[k, k] for k in range(i)))
if D[i, i].is_positive is False:
raise NonPositiveDefiniteMatrixError(
"Matrix must be positive-definite")
else:
for i in range(M.rows):
for j in range(i):
L[i, j] = (1 / D[j, j])*(M[i, j] - sum(
L[i, k]*L[j, k]*D[k, k] for k in range(j)))
D[i, i] = M[i, i] - sum(L[i, k]**2*D[k, k] for k in range(i))
return M._new(L), M._new(D)
def _LDLdecomposition_sparse(M, hermitian=True):
"""
Returns the LDL Decomposition (matrices ``L`` and ``D``) of matrix
``A``, such that ``L * D * L.T == A``. ``A`` must be a square,
symmetric, positive-definite and non-singular.
This method eliminates the use of square root and ensures that all
the diagonal entries of L are 1.
Examples
========
>>> from sympy import SparseMatrix
>>> A = SparseMatrix(((25, 15, -5), (15, 18, 0), (-5, 0, 11)))
>>> L, D = A.LDLdecomposition()
>>> L
Matrix([
[ 1, 0, 0],
[ 3/5, 1, 0],
[-1/5, 1/3, 1]])
>>> D
Matrix([
[25, 0, 0],
[ 0, 9, 0],
[ 0, 0, 9]])
>>> L * D * L.T == A
True
"""
from .dense import MutableDenseMatrix
if not M.is_square:
raise NonSquareMatrixError("Matrix must be square.")
if hermitian and not M.is_hermitian:
raise ValueError("Matrix must be Hermitian.")
if not hermitian and not M.is_symmetric():
raise ValueError("Matrix must be symmetric.")
dps = _get_intermediate_simp(expand_mul, expand_mul)
Lrowstruc = M.row_structure_symbolic_cholesky()
L = MutableDenseMatrix.eye(M.rows)
D = MutableDenseMatrix.zeros(M.rows, M.cols)
for i in range(len(Lrowstruc)):
for j in Lrowstruc[i]:
if i != j:
L[i, j] = M[i, j]
summ = 0
for p1 in Lrowstruc[i]:
if p1 < j:
for p2 in Lrowstruc[j]:
if p2 < j:
if p1 == p2:
if hermitian:
summ += L[i, p1]*L[j, p1].conjugate()*D[p1, p1]
else:
summ += L[i, p1]*L[j, p1]*D[p1, p1]
else:
break
else:
break
L[i, j] = dps((L[i, j] - summ) / D[j, j])
else: # i == j
D[i, i] = M[i, i]
summ = 0
for k in Lrowstruc[i]:
if k < i:
if hermitian:
summ += L[i, k]*L[i, k].conjugate()*D[k, k]
else:
summ += L[i, k]**2*D[k, k]
else:
break
D[i, i] = dps(D[i, i] - summ)
if hermitian and D[i, i].is_positive is False:
raise NonPositiveDefiniteMatrixError(
"Matrix must be positive-definite")
return M._new(L), M._new(D)
def _LUdecomposition(M, iszerofunc=_iszero, simpfunc=None, rankcheck=False):
"""Returns (L, U, perm) where L is a lower triangular matrix with unit
diagonal, U is an upper triangular matrix, and perm is a list of row
swap index pairs. If A is the original matrix, then
``A = (L*U).permuteBkwd(perm)``, and the row permutation matrix P such
that $P A = L U$ can be computed by ``P = eye(A.rows).permuteFwd(perm)``.
See documentation for LUCombined for details about the keyword argument
rankcheck, iszerofunc, and simpfunc.
Parameters
==========
rankcheck : bool, optional
Determines if this function should detect the rank
deficiency of the matrixis and should raise a
``ValueError``.
iszerofunc : function, optional
A function which determines if a given expression is zero.
The function should be a callable that takes a single
SymPy expression and returns a 3-valued boolean value
``True``, ``False``, or ``None``.
It is internally used by the pivot searching algorithm.
See the notes section for a more information about the
pivot searching algorithm.
simpfunc : function or None, optional
A function that simplifies the input.
If this is specified as a function, this function should be
a callable that takes a single SymPy expression and returns
an another SymPy expression that is algebraically
equivalent.
If ``None``, it indicates that the pivot search algorithm
should not attempt to simplify any candidate pivots.
It is internally used by the pivot searching algorithm.
See the notes section for a more information about the
pivot searching algorithm.
Examples
========
>>> from sympy import Matrix
>>> a = Matrix([[4, 3], [6, 3]])
>>> L, U, _ = a.LUdecomposition()
>>> L
Matrix([
[ 1, 0],
[3/2, 1]])
>>> U
Matrix([
[4, 3],
[0, -3/2]])
See Also
========
sympy.matrices.dense.DenseMatrix.cholesky
sympy.matrices.dense.DenseMatrix.LDLdecomposition
QRdecomposition
LUdecomposition_Simple
LUdecompositionFF
LUsolve
"""
combined, p = M.LUdecomposition_Simple(iszerofunc=iszerofunc,
simpfunc=simpfunc, rankcheck=rankcheck)
# L is lower triangular ``M.rows x M.rows``
# U is upper triangular ``M.rows x M.cols``
# L has unit diagonal. For each column in combined, the subcolumn
# below the diagonal of combined is shared by L.
# If L has more columns than combined, then the remaining subcolumns
# below the diagonal of L are zero.
# The upper triangular portion of L and combined are equal.
def entry_L(i, j):
if i < j:
# Super diagonal entry
return M.zero
elif i == j:
return M.one
elif j < combined.cols:
return combined[i, j]
# Subdiagonal entry of L with no corresponding
# entry in combined
return M.zero
def entry_U(i, j):
return M.zero if i > j else combined[i, j]
L = M._new(combined.rows, combined.rows, entry_L)
U = M._new(combined.rows, combined.cols, entry_U)
return L, U, p
def _LUdecomposition_Simple(M, iszerofunc=_iszero, simpfunc=None,
rankcheck=False):
r"""Compute the PLU decomposition of the matrix.
Parameters
==========
rankcheck : bool, optional
Determines if this function should detect the rank
deficiency of the matrixis and should raise a
``ValueError``.
iszerofunc : function, optional
A function which determines if a given expression is zero.
The function should be a callable that takes a single
SymPy expression and returns a 3-valued boolean value
``True``, ``False``, or ``None``.
It is internally used by the pivot searching algorithm.
See the notes section for a more information about the
pivot searching algorithm.
simpfunc : function or None, optional
A function that simplifies the input.
If this is specified as a function, this function should be
a callable that takes a single SymPy expression and returns
an another SymPy expression that is algebraically
equivalent.
If ``None``, it indicates that the pivot search algorithm
should not attempt to simplify any candidate pivots.
It is internally used by the pivot searching algorithm.
See the notes section for a more information about the
pivot searching algorithm.
Returns
=======
(lu, row_swaps) : (Matrix, list)
If the original matrix is a $m, n$ matrix:
*lu* is a $m, n$ matrix, which contains result of the
decomposition in a compressed form. See the notes section
to see how the matrix is compressed.
*row_swaps* is a $m$-element list where each element is a
pair of row exchange indices.
``A = (L*U).permute_backward(perm)``, and the row
permutation matrix $P$ from the formula $P A = L U$ can be
computed by ``P=eye(A.row).permute_forward(perm)``.
Raises
======
ValueError
Raised if ``rankcheck=True`` and the matrix is found to
be rank deficient during the computation.
Notes
=====
About the PLU decomposition:
PLU decomposition is a generalization of a LU decomposition
which can be extended for rank-deficient matrices.
It can further be generalized for non-square matrices, and this
is the notation that SymPy is using.
PLU decomposition is a decomposition of a $m, n$ matrix $A$ in
the form of $P A = L U$ where
* $L$ is a $m, m$ lower triangular matrix with unit diagonal
entries.
* $U$ is a $m, n$ upper triangular matrix.
* $P$ is a $m, m$ permutation matrix.
So, for a square matrix, the decomposition would look like:
.. math::
L = \begin{bmatrix}
1 & 0 & 0 & \cdots & 0 \\
L_{1, 0} & 1 & 0 & \cdots & 0 \\
L_{2, 0} & L_{2, 1} & 1 & \cdots & 0 \\
\vdots & \vdots & \vdots & \ddots & \vdots \\
L_{n-1, 0} & L_{n-1, 1} & L_{n-1, 2} & \cdots & 1
\end{bmatrix}
.. math::
U = \begin{bmatrix}
U_{0, 0} & U_{0, 1} & U_{0, 2} & \cdots & U_{0, n-1} \\
0 & U_{1, 1} & U_{1, 2} & \cdots & U_{1, n-1} \\
0 & 0 & U_{2, 2} & \cdots & U_{2, n-1} \\
\vdots & \vdots & \vdots & \ddots & \vdots \\
0 & 0 & 0 & \cdots & U_{n-1, n-1}
\end{bmatrix}
And for a matrix with more rows than the columns,
the decomposition would look like:
.. math::
L = \begin{bmatrix}
1 & 0 & 0 & \cdots & 0 & 0 & \cdots & 0 \\
L_{1, 0} & 1 & 0 & \cdots & 0 & 0 & \cdots & 0 \\
L_{2, 0} & L_{2, 1} & 1 & \cdots & 0 & 0 & \cdots & 0 \\
\vdots & \vdots & \vdots & \ddots & \vdots & \vdots & \ddots
& \vdots \\
L_{n-1, 0} & L_{n-1, 1} & L_{n-1, 2} & \cdots & 1 & 0
& \cdots & 0 \\
L_{n, 0} & L_{n, 1} & L_{n, 2} & \cdots & L_{n, n-1} & 1
& \cdots & 0 \\
\vdots & \vdots & \vdots & \ddots & \vdots & \vdots
& \ddots & \vdots \\
L_{m-1, 0} & L_{m-1, 1} & L_{m-1, 2} & \cdots & L_{m-1, n-1}
& 0 & \cdots & 1 \\
\end{bmatrix}
.. math::
U = \begin{bmatrix}
U_{0, 0} & U_{0, 1} & U_{0, 2} & \cdots & U_{0, n-1} \\
0 & U_{1, 1} & U_{1, 2} & \cdots & U_{1, n-1} \\
0 & 0 & U_{2, 2} & \cdots & U_{2, n-1} \\
\vdots & \vdots & \vdots & \ddots & \vdots \\
0 & 0 & 0 & \cdots & U_{n-1, n-1} \\
0 & 0 & 0 & \cdots & 0 \\
\vdots & \vdots & \vdots & \ddots & \vdots \\
0 & 0 & 0 & \cdots & 0
\end{bmatrix}
Finally, for a matrix with more columns than the rows, the
decomposition would look like:
.. math::
L = \begin{bmatrix}
1 & 0 & 0 & \cdots & 0 \\
L_{1, 0} & 1 & 0 & \cdots & 0 \\
L_{2, 0} & L_{2, 1} & 1 & \cdots & 0 \\
\vdots & \vdots & \vdots & \ddots & \vdots \\
L_{m-1, 0} & L_{m-1, 1} & L_{m-1, 2} & \cdots & 1
\end{bmatrix}
.. math::
U = \begin{bmatrix}
U_{0, 0} & U_{0, 1} & U_{0, 2} & \cdots & U_{0, m-1}
& \cdots & U_{0, n-1} \\
0 & U_{1, 1} & U_{1, 2} & \cdots & U_{1, m-1}
& \cdots & U_{1, n-1} \\
0 & 0 & U_{2, 2} & \cdots & U_{2, m-1}
& \cdots & U_{2, n-1} \\
\vdots & \vdots & \vdots & \ddots & \vdots
& \cdots & \vdots \\
0 & 0 & 0 & \cdots & U_{m-1, m-1}
& \cdots & U_{m-1, n-1} \\
\end{bmatrix}
About the compressed LU storage:
The results of the decomposition are often stored in compressed
forms rather than returning $L$ and $U$ matrices individually.
It may be less intiuitive, but it is commonly used for a lot of
numeric libraries because of the efficiency.
The storage matrix is defined as following for this specific
method:
* The subdiagonal elements of $L$ are stored in the subdiagonal
portion of $LU$, that is $LU_{i, j} = L_{i, j}$ whenever
$i > j$.
* The elements on the diagonal of $L$ are all 1, and are not
explicitly stored.
* $U$ is stored in the upper triangular portion of $LU$, that is
$LU_{i, j} = U_{i, j}$ whenever $i <= j$.
* For a case of $m > n$, the right side of the $L$ matrix is
trivial to store.
* For a case of $m < n$, the below side of the $U$ matrix is
trivial to store.
So, for a square matrix, the compressed output matrix would be:
.. math::
LU = \begin{bmatrix}
U_{0, 0} & U_{0, 1} & U_{0, 2} & \cdots & U_{0, n-1} \\
L_{1, 0} & U_{1, 1} & U_{1, 2} & \cdots & U_{1, n-1} \\
L_{2, 0} & L_{2, 1} & U_{2, 2} & \cdots & U_{2, n-1} \\
\vdots & \vdots & \vdots & \ddots & \vdots \\
L_{n-1, 0} & L_{n-1, 1} & L_{n-1, 2} & \cdots & U_{n-1, n-1}
\end{bmatrix}
For a matrix with more rows than the columns, the compressed
output matrix would be:
.. math::
LU = \begin{bmatrix}
U_{0, 0} & U_{0, 1} & U_{0, 2} & \cdots & U_{0, n-1} \\
L_{1, 0} & U_{1, 1} & U_{1, 2} & \cdots & U_{1, n-1} \\
L_{2, 0} & L_{2, 1} & U_{2, 2} & \cdots & U_{2, n-1} \\
\vdots & \vdots & \vdots & \ddots & \vdots \\
L_{n-1, 0} & L_{n-1, 1} & L_{n-1, 2} & \cdots
& U_{n-1, n-1} \\
\vdots & \vdots & \vdots & \ddots & \vdots \\
L_{m-1, 0} & L_{m-1, 1} & L_{m-1, 2} & \cdots
& L_{m-1, n-1} \\
\end{bmatrix}
For a matrix with more columns than the rows, the compressed
output matrix would be:
.. math::
LU = \begin{bmatrix}
U_{0, 0} & U_{0, 1} & U_{0, 2} & \cdots & U_{0, m-1}
& \cdots & U_{0, n-1} \\
L_{1, 0} & U_{1, 1} & U_{1, 2} & \cdots & U_{1, m-1}
& \cdots & U_{1, n-1} \\
L_{2, 0} & L_{2, 1} & U_{2, 2} & \cdots & U_{2, m-1}
& \cdots & U_{2, n-1} \\
\vdots & \vdots & \vdots & \ddots & \vdots
& \cdots & \vdots \\
L_{m-1, 0} & L_{m-1, 1} & L_{m-1, 2} & \cdots & U_{m-1, m-1}
& \cdots & U_{m-1, n-1} \\
\end{bmatrix}
About the pivot searching algorithm:
When a matrix contains symbolic entries, the pivot search algorithm
differs from the case where every entry can be categorized as zero or
nonzero.
The algorithm searches column by column through the submatrix whose
top left entry coincides with the pivot position.
If it exists, the pivot is the first entry in the current search
column that iszerofunc guarantees is nonzero.
If no such candidate exists, then each candidate pivot is simplified
if simpfunc is not None.
The search is repeated, with the difference that a candidate may be
the pivot if ``iszerofunc()`` cannot guarantee that it is nonzero.
In the second search the pivot is the first candidate that
iszerofunc can guarantee is nonzero.
If no such candidate exists, then the pivot is the first candidate
for which iszerofunc returns None.
If no such candidate exists, then the search is repeated in the next
column to the right.
The pivot search algorithm differs from the one in ``rref()``, which
relies on ``_find_reasonable_pivot()``.
Future versions of ``LUdecomposition_simple()`` may use
``_find_reasonable_pivot()``.
See Also
========
sympy.matrices.matrixbase.MatrixBase.LUdecomposition
LUdecompositionFF
LUsolve
"""
if rankcheck:
# https://github.com/sympy/sympy/issues/9796
pass
if S.Zero in M.shape:
# Define LU decomposition of a matrix with no entries as a matrix
# of the same dimensions with all zero entries.
return M.zeros(M.rows, M.cols), []
dps = _get_intermediate_simp()
lu = M.as_mutable()
row_swaps = []
pivot_col = 0
for pivot_row in range(0, lu.rows - 1):
# Search for pivot. Prefer entry that iszeropivot determines
# is nonzero, over entry that iszeropivot cannot guarantee
# is zero.
# XXX ``_find_reasonable_pivot`` uses slow zero testing. Blocked by bug #10279
# Future versions of LUdecomposition_simple can pass iszerofunc and simpfunc
# to _find_reasonable_pivot().
# In pass 3 of _find_reasonable_pivot(), the predicate in ``if x.equals(S.Zero):``
# calls sympy.simplify(), and not the simplification function passed in via
# the keyword argument simpfunc.
iszeropivot = True
while pivot_col != M.cols and iszeropivot:
sub_col = (lu[r, pivot_col] for r in range(pivot_row, M.rows))
pivot_row_offset, pivot_value, is_assumed_non_zero, ind_simplified_pairs =\
_find_reasonable_pivot_naive(sub_col, iszerofunc, simpfunc)
iszeropivot = pivot_value is None
if iszeropivot:
# All candidate pivots in this column are zero.
# Proceed to next column.
pivot_col += 1
if rankcheck and pivot_col != pivot_row:
# All entries including and below the pivot position are
# zero, which indicates that the rank of the matrix is
# strictly less than min(num rows, num cols)
# Mimic behavior of previous implementation, by throwing a
# ValueError.
raise ValueError("Rank of matrix is strictly less than"
" number of rows or columns."
" Pass keyword argument"
" rankcheck=False to compute"
" the LU decomposition of this matrix.")
candidate_pivot_row = None if pivot_row_offset is None else pivot_row + pivot_row_offset
if candidate_pivot_row is None and iszeropivot:
# If candidate_pivot_row is None and iszeropivot is True
# after pivot search has completed, then the submatrix
# below and to the right of (pivot_row, pivot_col) is
# all zeros, indicating that Gaussian elimination is
# complete.
return lu, row_swaps
# Update entries simplified during pivot search.
for offset, val in ind_simplified_pairs:
lu[pivot_row + offset, pivot_col] = val
if pivot_row != candidate_pivot_row:
# Row swap book keeping:
# Record which rows were swapped.
# Update stored portion of L factor by multiplying L on the
# left and right with the current permutation.
# Swap rows of U.
row_swaps.append([pivot_row, candidate_pivot_row])
# Update L.
lu[pivot_row, 0:pivot_row], lu[candidate_pivot_row, 0:pivot_row] = \
lu[candidate_pivot_row, 0:pivot_row], lu[pivot_row, 0:pivot_row]
# Swap pivot row of U with candidate pivot row.
lu[pivot_row, pivot_col:lu.cols], lu[candidate_pivot_row, pivot_col:lu.cols] = \
lu[candidate_pivot_row, pivot_col:lu.cols], lu[pivot_row, pivot_col:lu.cols]
# Introduce zeros below the pivot by adding a multiple of the
# pivot row to a row under it, and store the result in the
# row under it.
# Only entries in the target row whose index is greater than
# start_col may be nonzero.
start_col = pivot_col + 1
for row in range(pivot_row + 1, lu.rows):
# Store factors of L in the subcolumn below
# (pivot_row, pivot_row).
lu[row, pivot_row] = \
dps(lu[row, pivot_col]/lu[pivot_row, pivot_col])
# Form the linear combination of the pivot row and the current
# row below the pivot row that zeros the entries below the pivot.
# Employing slicing instead of a loop here raises
# NotImplementedError: Cannot add Zero to MutableSparseMatrix
# in sympy/matrices/tests/test_sparse.py.
# c = pivot_row + 1 if pivot_row == pivot_col else pivot_col
for c in range(start_col, lu.cols):
lu[row, c] = dps(lu[row, c] - lu[row, pivot_row]*lu[pivot_row, c])
if pivot_row != pivot_col:
# matrix rank < min(num rows, num cols),
# so factors of L are not stored directly below the pivot.
# These entries are zero by construction, so don't bother
# computing them.
for row in range(pivot_row + 1, lu.rows):
lu[row, pivot_col] = M.zero
pivot_col += 1
if pivot_col == lu.cols:
# All candidate pivots are zero implies that Gaussian
# elimination is complete.
return lu, row_swaps
if rankcheck:
if iszerofunc(
lu[Min(lu.rows, lu.cols) - 1, Min(lu.rows, lu.cols) - 1]):
raise ValueError("Rank of matrix is strictly less than"
" number of rows or columns."
" Pass keyword argument"
" rankcheck=False to compute"
" the LU decomposition of this matrix.")
return lu, row_swaps
def _LUdecompositionFF(M):
"""Compute a fraction-free LU decomposition.
Returns 4 matrices P, L, D, U such that PA = L D**-1 U.
If the elements of the matrix belong to some integral domain I, then all
elements of L, D and U are guaranteed to belong to I.
See Also
========
sympy.matrices.matrixbase.MatrixBase.LUdecomposition
LUdecomposition_Simple
LUsolve
References
==========
.. [1] W. Zhou & D.J. Jeffrey, "Fraction-free matrix factors: new forms
for LU and QR factors". Frontiers in Computer Science in China,
Vol 2, no. 1, pp. 67-80, 2008.
"""
from sympy.matrices import SparseMatrix
zeros = SparseMatrix.zeros
eye = SparseMatrix.eye
n, m = M.rows, M.cols
U, L, P = M.as_mutable(), eye(n), eye(n)
DD = zeros(n, n)
oldpivot = 1
for k in range(n - 1):
if U[k, k] == 0:
for kpivot in range(k + 1, n):
if U[kpivot, k]:
break
else:
raise ValueError("Matrix is not full rank")
U[k, k:], U[kpivot, k:] = U[kpivot, k:], U[k, k:]
L[k, :k], L[kpivot, :k] = L[kpivot, :k], L[k, :k]
P[k, :], P[kpivot, :] = P[kpivot, :], P[k, :]
L [k, k] = Ukk = U[k, k]
DD[k, k] = oldpivot * Ukk
for i in range(k + 1, n):
L[i, k] = Uik = U[i, k]
for j in range(k + 1, m):
U[i, j] = (Ukk * U[i, j] - U[k, j] * Uik) / oldpivot
U[i, k] = 0
oldpivot = Ukk
DD[n - 1, n - 1] = oldpivot
return P, L, DD, U
def _singular_value_decomposition(A):
r"""Returns a Condensed Singular Value decomposition.
Explanation
===========
A Singular Value decomposition is a decomposition in the form $A = U \Sigma V^H$
where
- $U, V$ are column orthogonal matrix.
- $\Sigma$ is a diagonal matrix, where the main diagonal contains singular
values of matrix A.
A column orthogonal matrix satisfies
$\mathbb{I} = U^H U$ while a full orthogonal matrix satisfies
relation $\mathbb{I} = U U^H = U^H U$ where $\mathbb{I}$ is an identity
matrix with matching dimensions.
For matrices which are not square or are rank-deficient, it is
sufficient to return a column orthogonal matrix because augmenting
them may introduce redundant computations.
In condensed Singular Value Decomposition we only return column orthogonal
matrices because of this reason
If you want to augment the results to return a full orthogonal
decomposition, you should use the following procedures.
- Augment the $U, V$ matrices with columns that are orthogonal to every
other columns and make it square.
- Augment the $\Sigma$ matrix with zero rows to make it have the same
shape as the original matrix.
The procedure will be illustrated in the examples section.
Examples
========
we take a full rank matrix first:
>>> from sympy import Matrix
>>> A = Matrix([[1, 2],[2,1]])
>>> U, S, V = A.singular_value_decomposition()
>>> U
Matrix([
[ sqrt(2)/2, sqrt(2)/2],
[-sqrt(2)/2, sqrt(2)/2]])
>>> S
Matrix([
[1, 0],
[0, 3]])
>>> V
Matrix([
[-sqrt(2)/2, sqrt(2)/2],
[ sqrt(2)/2, sqrt(2)/2]])
If a matrix if square and full rank both U, V
are orthogonal in both directions
>>> U * U.H
Matrix([
[1, 0],
[0, 1]])
>>> U.H * U
Matrix([
[1, 0],
[0, 1]])
>>> V * V.H
Matrix([
[1, 0],
[0, 1]])
>>> V.H * V
Matrix([
[1, 0],
[0, 1]])
>>> A == U * S * V.H
True
>>> C = Matrix([
... [1, 0, 0, 0, 2],
... [0, 0, 3, 0, 0],
... [0, 0, 0, 0, 0],
... [0, 2, 0, 0, 0],
... ])
>>> U, S, V = C.singular_value_decomposition()
>>> V.H * V
Matrix([
[1, 0, 0],
[0, 1, 0],
[0, 0, 1]])
>>> V * V.H
Matrix([
[1/5, 0, 0, 0, 2/5],
[ 0, 1, 0, 0, 0],
[ 0, 0, 1, 0, 0],
[ 0, 0, 0, 0, 0],
[2/5, 0, 0, 0, 4/5]])
If you want to augment the results to be a full orthogonal
decomposition, you should augment $V$ with an another orthogonal
column.
You are able to append an arbitrary standard basis that are linearly
independent to every other columns and you can run the Gram-Schmidt
process to make them augmented as orthogonal basis.
>>> V_aug = V.row_join(Matrix([[0,0,0,0,1],
... [0,0,0,1,0]]).H)
>>> V_aug = V_aug.QRdecomposition()[0]
>>> V_aug
Matrix([
[0, sqrt(5)/5, 0, -2*sqrt(5)/5, 0],
[1, 0, 0, 0, 0],
[0, 0, 1, 0, 0],
[0, 0, 0, 0, 1],
[0, 2*sqrt(5)/5, 0, sqrt(5)/5, 0]])
>>> V_aug.H * V_aug
Matrix([
[1, 0, 0, 0, 0],
[0, 1, 0, 0, 0],
[0, 0, 1, 0, 0],
[0, 0, 0, 1, 0],
[0, 0, 0, 0, 1]])
>>> V_aug * V_aug.H
Matrix([
[1, 0, 0, 0, 0],
[0, 1, 0, 0, 0],
[0, 0, 1, 0, 0],
[0, 0, 0, 1, 0],
[0, 0, 0, 0, 1]])
Similarly we augment U
>>> U_aug = U.row_join(Matrix([0,0,1,0]))
>>> U_aug = U_aug.QRdecomposition()[0]
>>> U_aug
Matrix([
[0, 1, 0, 0],
[0, 0, 1, 0],
[0, 0, 0, 1],
[1, 0, 0, 0]])
>>> U_aug.H * U_aug
Matrix([
[1, 0, 0, 0],
[0, 1, 0, 0],
[0, 0, 1, 0],
[0, 0, 0, 1]])
>>> U_aug * U_aug.H
Matrix([
[1, 0, 0, 0],
[0, 1, 0, 0],
[0, 0, 1, 0],
[0, 0, 0, 1]])
We add 2 zero columns and one row to S
>>> S_aug = S.col_join(Matrix([[0,0,0]]))
>>> S_aug = S_aug.row_join(Matrix([[0,0,0,0],
... [0,0,0,0]]).H)
>>> S_aug
Matrix([
[2, 0, 0, 0, 0],
[0, sqrt(5), 0, 0, 0],
[0, 0, 3, 0, 0],
[0, 0, 0, 0, 0]])
>>> U_aug * S_aug * V_aug.H == C
True
"""
AH = A.H
m, n = A.shape
if m >= n:
V, S = (AH * A).diagonalize()
ranked = []
for i, x in enumerate(S.diagonal()):
if not x.is_zero:
ranked.append(i)
V = V[:, ranked]
Singular_vals = [sqrt(S[i, i]) for i in range(S.rows) if i in ranked]
S = S.diag(*Singular_vals)
V, _ = V.QRdecomposition()
U = A * V * S.inv()
else:
U, S = (A * AH).diagonalize()
ranked = []
for i, x in enumerate(S.diagonal()):
if not x.is_zero:
ranked.append(i)
U = U[:, ranked]
Singular_vals = [sqrt(S[i, i]) for i in range(S.rows) if i in ranked]
S = S.diag(*Singular_vals)
U, _ = U.QRdecomposition()
V = AH * U * S.inv()
return U, S, V
def _QRdecomposition_optional(M, normalize=True):
def dot(u, v):
return u.dot(v, hermitian=True)
dps = _get_intermediate_simp(expand_mul, expand_mul)
A = M.as_mutable()
ranked = []
Q = A
R = A.zeros(A.cols)
for j in range(A.cols):
for i in range(j):
if Q[:, i].is_zero_matrix:
continue
R[i, j] = dot(Q[:, i], Q[:, j]) / dot(Q[:, i], Q[:, i])
R[i, j] = dps(R[i, j])
Q[:, j] -= Q[:, i] * R[i, j]
Q[:, j] = dps(Q[:, j])
if Q[:, j].is_zero_matrix is not True:
ranked.append(j)
R[j, j] = M.one
Q = Q.extract(range(Q.rows), ranked)
R = R.extract(ranked, range(R.cols))
if normalize:
# Normalization
for i in range(Q.cols):
norm = Q[:, i].norm()
Q[:, i] /= norm
R[i, :] *= norm
return M.__class__(Q), M.__class__(R)
def _QRdecomposition(M):
r"""Returns a QR decomposition.
Explanation
===========
A QR decomposition is a decomposition in the form $A = Q R$
where
- $Q$ is a column orthogonal matrix.
- $R$ is a upper triangular (trapezoidal) matrix.
A column orthogonal matrix satisfies
$\mathbb{I} = Q^H Q$ while a full orthogonal matrix satisfies
relation $\mathbb{I} = Q Q^H = Q^H Q$ where $I$ is an identity
matrix with matching dimensions.
For matrices which are not square or are rank-deficient, it is
sufficient to return a column orthogonal matrix because augmenting
them may introduce redundant computations.
And an another advantage of this is that you can easily inspect the
matrix rank by counting the number of columns of $Q$.
If you want to augment the results to return a full orthogonal
decomposition, you should use the following procedures.
- Augment the $Q$ matrix with columns that are orthogonal to every
other columns and make it square.
- Augment the $R$ matrix with zero rows to make it have the same
shape as the original matrix.
The procedure will be illustrated in the examples section.
Examples
========
A full rank matrix example:
>>> from sympy import Matrix
>>> A = Matrix([[12, -51, 4], [6, 167, -68], [-4, 24, -41]])
>>> Q, R = A.QRdecomposition()
>>> Q
Matrix([
[ 6/7, -69/175, -58/175],
[ 3/7, 158/175, 6/175],
[-2/7, 6/35, -33/35]])
>>> R
Matrix([
[14, 21, -14],
[ 0, 175, -70],
[ 0, 0, 35]])
If the matrix is square and full rank, the $Q$ matrix becomes
orthogonal in both directions, and needs no augmentation.
>>> Q * Q.H
Matrix([
[1, 0, 0],
[0, 1, 0],
[0, 0, 1]])
>>> Q.H * Q
Matrix([
[1, 0, 0],
[0, 1, 0],
[0, 0, 1]])
>>> A == Q*R
True
A rank deficient matrix example:
>>> A = Matrix([[12, -51, 0], [6, 167, 0], [-4, 24, 0]])
>>> Q, R = A.QRdecomposition()
>>> Q
Matrix([
[ 6/7, -69/175],
[ 3/7, 158/175],
[-2/7, 6/35]])
>>> R
Matrix([
[14, 21, 0],
[ 0, 175, 0]])
QRdecomposition might return a matrix Q that is rectangular.
In this case the orthogonality condition might be satisfied as
$\mathbb{I} = Q.H*Q$ but not in the reversed product
$\mathbb{I} = Q * Q.H$.
>>> Q.H * Q
Matrix([
[1, 0],
[0, 1]])
>>> Q * Q.H
Matrix([
[27261/30625, 348/30625, -1914/6125],
[ 348/30625, 30589/30625, 198/6125],
[ -1914/6125, 198/6125, 136/1225]])
If you want to augment the results to be a full orthogonal
decomposition, you should augment $Q$ with an another orthogonal
column.
You are able to append an identity matrix,
and you can run the Gram-Schmidt
process to make them augmented as orthogonal basis.
>>> Q_aug = Q.row_join(Matrix.eye(3))
>>> Q_aug = Q_aug.QRdecomposition()[0]
>>> Q_aug
Matrix([
[ 6/7, -69/175, 58/175],
[ 3/7, 158/175, -6/175],
[-2/7, 6/35, 33/35]])
>>> Q_aug.H * Q_aug
Matrix([
[1, 0, 0],
[0, 1, 0],
[0, 0, 1]])
>>> Q_aug * Q_aug.H
Matrix([
[1, 0, 0],
[0, 1, 0],
[0, 0, 1]])
Augmenting the $R$ matrix with zero row is straightforward.
>>> R_aug = R.col_join(Matrix([[0, 0, 0]]))
>>> R_aug
Matrix([
[14, 21, 0],
[ 0, 175, 0],
[ 0, 0, 0]])
>>> Q_aug * R_aug == A
True
A zero matrix example:
>>> from sympy import Matrix
>>> A = Matrix.zeros(3, 4)
>>> Q, R = A.QRdecomposition()
They may return matrices with zero rows and columns.
>>> Q
Matrix(3, 0, [])
>>> R
Matrix(0, 4, [])
>>> Q*R
Matrix([
[0, 0, 0, 0],
[0, 0, 0, 0],
[0, 0, 0, 0]])
As the same augmentation rule described above, $Q$ can be augmented
with columns of an identity matrix and $R$ can be augmented with
rows of a zero matrix.
>>> Q_aug = Q.row_join(Matrix.eye(3))
>>> R_aug = R.col_join(Matrix.zeros(3, 4))
>>> Q_aug * Q_aug.T
Matrix([
[1, 0, 0],
[0, 1, 0],
[0, 0, 1]])
>>> R_aug
Matrix([
[0, 0, 0, 0],
[0, 0, 0, 0],
[0, 0, 0, 0]])
>>> Q_aug * R_aug == A
True
See Also
========
sympy.matrices.dense.DenseMatrix.cholesky
sympy.matrices.dense.DenseMatrix.LDLdecomposition
sympy.matrices.matrixbase.MatrixBase.LUdecomposition
QRsolve
"""
return _QRdecomposition_optional(M, normalize=True)
def _upper_hessenberg_decomposition(A):
"""Converts a matrix into Hessenberg matrix H.
Returns 2 matrices H, P s.t.
$P H P^{T} = A$, where H is an upper hessenberg matrix
and P is an orthogonal matrix
Examples
========
>>> from sympy import Matrix
>>> A = Matrix([
... [1,2,3],
... [-3,5,6],
... [4,-8,9],
... ])
>>> H, P = A.upper_hessenberg_decomposition()
>>> H
Matrix([
[1, 6/5, 17/5],
[5, 213/25, -134/25],
[0, 216/25, 137/25]])
>>> P
Matrix([
[1, 0, 0],
[0, -3/5, 4/5],
[0, 4/5, 3/5]])
>>> P * H * P.H == A
True
References
==========
.. [#] https://mathworld.wolfram.com/HessenbergDecomposition.html
"""
M = A.as_mutable()
if not M.is_square:
raise NonSquareMatrixError("Matrix must be square.")
n = M.cols
P = M.eye(n)
H = M
for j in range(n - 2):
u = H[j + 1:, j]
if u[1:, :].is_zero_matrix:
continue
if sign(u[0]) != 0:
u[0] = u[0] + sign(u[0]) * u.norm()
else:
u[0] = u[0] + u.norm()
v = u / u.norm()
H[j + 1:, :] = H[j + 1:, :] - 2 * v * (v.H * H[j + 1:, :])
H[:, j + 1:] = H[:, j + 1:] - (H[:, j + 1:] * (2 * v)) * v.H
P[:, j + 1:] = P[:, j + 1:] - (P[:, j + 1:] * (2 * v)) * v.H
return H, P
PK ]ZZZD�`L�v �v sympy/matrices/dense.pyimport random
from sympy.core.basic import Basic
from sympy.core.singleton import S
from sympy.core.symbol import Symbol
from sympy.core.sympify import sympify
from sympy.functions.elementary.trigonometric import cos, sin
from sympy.utilities.decorator import doctest_depends_on
from sympy.utilities.exceptions import sympy_deprecation_warning
from sympy.utilities.iterables import is_sequence
from .exceptions import ShapeError
from .decompositions import _cholesky, _LDLdecomposition
from .matrixbase import MatrixBase
from .repmatrix import MutableRepMatrix, RepMatrix
from .solvers import _lower_triangular_solve, _upper_triangular_solve
__doctest_requires__ = {('symarray',): ['numpy']}
def _iszero(x):
"""Returns True if x is zero."""
return x.is_zero
class DenseMatrix(RepMatrix):
"""Matrix implementation based on DomainMatrix as the internal representation"""
#
# DenseMatrix is a superclass for both MutableDenseMatrix and
# ImmutableDenseMatrix. Methods shared by both classes but not for the
# Sparse classes should be implemented here.
#
is_MatrixExpr = False # type: bool
_op_priority = 10.01
_class_priority = 4
@property
def _mat(self):
sympy_deprecation_warning(
"""
The private _mat attribute of Matrix is deprecated. Use the
.flat() method instead.
""",
deprecated_since_version="1.9",
active_deprecations_target="deprecated-private-matrix-attributes"
)
return self.flat()
def _eval_inverse(self, **kwargs):
return self.inv(method=kwargs.get('method', 'GE'),
iszerofunc=kwargs.get('iszerofunc', _iszero),
try_block_diag=kwargs.get('try_block_diag', False))
def as_immutable(self):
"""Returns an Immutable version of this Matrix
"""
from .immutable import ImmutableDenseMatrix as cls
return cls._fromrep(self._rep.copy())
def as_mutable(self):
"""Returns a mutable version of this matrix
Examples
========
>>> from sympy import ImmutableMatrix
>>> X = ImmutableMatrix([[1, 2], [3, 4]])
>>> Y = X.as_mutable()
>>> Y[1, 1] = 5 # Can set values in Y
>>> Y
Matrix([
[1, 2],
[3, 5]])
"""
return Matrix(self)
def cholesky(self, hermitian=True):
return _cholesky(self, hermitian=hermitian)
def LDLdecomposition(self, hermitian=True):
return _LDLdecomposition(self, hermitian=hermitian)
def lower_triangular_solve(self, rhs):
return _lower_triangular_solve(self, rhs)
def upper_triangular_solve(self, rhs):
return _upper_triangular_solve(self, rhs)
cholesky.__doc__ = _cholesky.__doc__
LDLdecomposition.__doc__ = _LDLdecomposition.__doc__
lower_triangular_solve.__doc__ = _lower_triangular_solve.__doc__
upper_triangular_solve.__doc__ = _upper_triangular_solve.__doc__
def _force_mutable(x):
"""Return a matrix as a Matrix, otherwise return x."""
if getattr(x, 'is_Matrix', False):
return x.as_mutable()
elif isinstance(x, Basic):
return x
elif hasattr(x, '__array__'):
a = x.__array__()
if len(a.shape) == 0:
return sympify(a)
return Matrix(x)
return x
class MutableDenseMatrix(DenseMatrix, MutableRepMatrix):
def simplify(self, **kwargs):
"""Applies simplify to the elements of a matrix in place.
This is a shortcut for M.applyfunc(lambda x: simplify(x, ratio, measure))
See Also
========
sympy.simplify.simplify.simplify
"""
from sympy.simplify.simplify import simplify as _simplify
for (i, j), element in self.todok().items():
self[i, j] = _simplify(element, **kwargs)
MutableMatrix = Matrix = MutableDenseMatrix
###########
# Numpy Utility Functions:
# list2numpy, matrix2numpy, symmarray
###########
def list2numpy(l, dtype=object): # pragma: no cover
"""Converts Python list of SymPy expressions to a NumPy array.
See Also
========
matrix2numpy
"""
from numpy import empty
a = empty(len(l), dtype)
for i, s in enumerate(l):
a[i] = s
return a
def matrix2numpy(m, dtype=object): # pragma: no cover
"""Converts SymPy's matrix to a NumPy array.
See Also
========
list2numpy
"""
from numpy import empty
a = empty(m.shape, dtype)
for i in range(m.rows):
for j in range(m.cols):
a[i, j] = m[i, j]
return a
###########
# Rotation matrices:
# rot_givens, rot_axis[123], rot_ccw_axis[123]
###########
def rot_givens(i, j, theta, dim=3):
r"""Returns a a Givens rotation matrix, a a rotation in the
plane spanned by two coordinates axes.
Explanation
===========
The Givens rotation corresponds to a generalization of rotation
matrices to any number of dimensions, given by:
.. math::
G(i, j, \theta) =
\begin{bmatrix}
1 & \cdots & 0 & \cdots & 0 & \cdots & 0 \\
\vdots & \ddots & \vdots & & \vdots & & \vdots \\
0 & \cdots & c & \cdots & -s & \cdots & 0 \\
\vdots & & \vdots & \ddots & \vdots & & \vdots \\
0 & \cdots & s & \cdots & c & \cdots & 0 \\
\vdots & & \vdots & & \vdots & \ddots & \vdots \\
0 & \cdots & 0 & \cdots & 0 & \cdots & 1
\end{bmatrix}
Where $c = \cos(\theta)$ and $s = \sin(\theta)$ appear at the intersections
``i``\th and ``j``\th rows and columns.
For fixed ``i > j``\, the non-zero elements of a Givens matrix are
given by:
- $g_{kk} = 1$ for $k \ne i,\,j$
- $g_{kk} = c$ for $k = i,\,j$
- $g_{ji} = -g_{ij} = -s$
Parameters
==========
i : int between ``0`` and ``dim - 1``
Represents first axis
j : int between ``0`` and ``dim - 1``
Represents second axis
dim : int bigger than 1
Number of dimentions. Defaults to 3.
Examples
========
>>> from sympy import pi, rot_givens
A counterclockwise rotation of pi/3 (60 degrees) around
the third axis (z-axis):
>>> rot_givens(1, 0, pi/3)
Matrix([
[ 1/2, -sqrt(3)/2, 0],
[sqrt(3)/2, 1/2, 0],
[ 0, 0, 1]])
If we rotate by pi/2 (90 degrees):
>>> rot_givens(1, 0, pi/2)
Matrix([
[0, -1, 0],
[1, 0, 0],
[0, 0, 1]])
This can be generalized to any number
of dimensions:
>>> rot_givens(1, 0, pi/2, dim=4)
Matrix([
[0, -1, 0, 0],
[1, 0, 0, 0],
[0, 0, 1, 0],
[0, 0, 0, 1]])
References
==========
.. [1] https://en.wikipedia.org/wiki/Givens_rotation
See Also
========
rot_axis1: Returns a rotation matrix for a rotation of theta (in radians)
about the 1-axis (clockwise around the x axis)
rot_axis2: Returns a rotation matrix for a rotation of theta (in radians)
about the 2-axis (clockwise around the y axis)
rot_axis3: Returns a rotation matrix for a rotation of theta (in radians)
about the 3-axis (clockwise around the z axis)
rot_ccw_axis1: Returns a rotation matrix for a rotation of theta (in radians)
about the 1-axis (counterclockwise around the x axis)
rot_ccw_axis2: Returns a rotation matrix for a rotation of theta (in radians)
about the 2-axis (counterclockwise around the y axis)
rot_ccw_axis3: Returns a rotation matrix for a rotation of theta (in radians)
about the 3-axis (counterclockwise around the z axis)
"""
if not isinstance(dim, int) or dim < 2:
raise ValueError('dim must be an integer biggen than one, '
'got {}.'.format(dim))
if i == j:
raise ValueError('i and j must be different, '
'got ({}, {})'.format(i, j))
for ij in [i, j]:
if not isinstance(ij, int) or ij < 0 or ij > dim - 1:
raise ValueError('i and j must be integers between 0 and '
'{}, got i={} and j={}.'.format(dim-1, i, j))
theta = sympify(theta)
c = cos(theta)
s = sin(theta)
M = eye(dim)
M[i, i] = c
M[j, j] = c
M[i, j] = s
M[j, i] = -s
return M
def rot_axis3(theta):
r"""Returns a rotation matrix for a rotation of theta (in radians)
about the 3-axis.
Explanation
===========
For a right-handed coordinate system, this corresponds to a
clockwise rotation around the `z`-axis, given by:
.. math::
R = \begin{bmatrix}
\cos(\theta) & \sin(\theta) & 0 \\
-\sin(\theta) & \cos(\theta) & 0 \\
0 & 0 & 1
\end{bmatrix}
Examples
========
>>> from sympy import pi, rot_axis3
A rotation of pi/3 (60 degrees):
>>> theta = pi/3
>>> rot_axis3(theta)
Matrix([
[ 1/2, sqrt(3)/2, 0],
[-sqrt(3)/2, 1/2, 0],
[ 0, 0, 1]])
If we rotate by pi/2 (90 degrees):
>>> rot_axis3(pi/2)
Matrix([
[ 0, 1, 0],
[-1, 0, 0],
[ 0, 0, 1]])
See Also
========
rot_givens: Returns a Givens rotation matrix (generalized rotation for
any number of dimensions)
rot_ccw_axis3: Returns a rotation matrix for a rotation of theta (in radians)
about the 3-axis (counterclockwise around the z axis)
rot_axis1: Returns a rotation matrix for a rotation of theta (in radians)
about the 1-axis (clockwise around the x axis)
rot_axis2: Returns a rotation matrix for a rotation of theta (in radians)
about the 2-axis (clockwise around the y axis)
"""
return rot_givens(0, 1, theta, dim=3)
def rot_axis2(theta):
r"""Returns a rotation matrix for a rotation of theta (in radians)
about the 2-axis.
Explanation
===========
For a right-handed coordinate system, this corresponds to a
clockwise rotation around the `y`-axis, given by:
.. math::
R = \begin{bmatrix}
\cos(\theta) & 0 & -\sin(\theta) \\
0 & 1 & 0 \\
\sin(\theta) & 0 & \cos(\theta)
\end{bmatrix}
Examples
========
>>> from sympy import pi, rot_axis2
A rotation of pi/3 (60 degrees):
>>> theta = pi/3
>>> rot_axis2(theta)
Matrix([
[ 1/2, 0, -sqrt(3)/2],
[ 0, 1, 0],
[sqrt(3)/2, 0, 1/2]])
If we rotate by pi/2 (90 degrees):
>>> rot_axis2(pi/2)
Matrix([
[0, 0, -1],
[0, 1, 0],
[1, 0, 0]])
See Also
========
rot_givens: Returns a Givens rotation matrix (generalized rotation for
any number of dimensions)
rot_ccw_axis2: Returns a rotation matrix for a rotation of theta (in radians)
about the 2-axis (clockwise around the y axis)
rot_axis1: Returns a rotation matrix for a rotation of theta (in radians)
about the 1-axis (counterclockwise around the x axis)
rot_axis3: Returns a rotation matrix for a rotation of theta (in radians)
about the 3-axis (counterclockwise around the z axis)
"""
return rot_givens(2, 0, theta, dim=3)
def rot_axis1(theta):
r"""Returns a rotation matrix for a rotation of theta (in radians)
about the 1-axis.
Explanation
===========
For a right-handed coordinate system, this corresponds to a
clockwise rotation around the `x`-axis, given by:
.. math::
R = \begin{bmatrix}
1 & 0 & 0 \\
0 & \cos(\theta) & \sin(\theta) \\
0 & -\sin(\theta) & \cos(\theta)
\end{bmatrix}
Examples
========
>>> from sympy import pi, rot_axis1
A rotation of pi/3 (60 degrees):
>>> theta = pi/3
>>> rot_axis1(theta)
Matrix([
[1, 0, 0],
[0, 1/2, sqrt(3)/2],
[0, -sqrt(3)/2, 1/2]])
If we rotate by pi/2 (90 degrees):
>>> rot_axis1(pi/2)
Matrix([
[1, 0, 0],
[0, 0, 1],
[0, -1, 0]])
See Also
========
rot_givens: Returns a Givens rotation matrix (generalized rotation for
any number of dimensions)
rot_ccw_axis1: Returns a rotation matrix for a rotation of theta (in radians)
about the 1-axis (counterclockwise around the x axis)
rot_axis2: Returns a rotation matrix for a rotation of theta (in radians)
about the 2-axis (clockwise around the y axis)
rot_axis3: Returns a rotation matrix for a rotation of theta (in radians)
about the 3-axis (clockwise around the z axis)
"""
return rot_givens(1, 2, theta, dim=3)
def rot_ccw_axis3(theta):
r"""Returns a rotation matrix for a rotation of theta (in radians)
about the 3-axis.
Explanation
===========
For a right-handed coordinate system, this corresponds to a
counterclockwise rotation around the `z`-axis, given by:
.. math::
R = \begin{bmatrix}
\cos(\theta) & -\sin(\theta) & 0 \\
\sin(\theta) & \cos(\theta) & 0 \\
0 & 0 & 1
\end{bmatrix}
Examples
========
>>> from sympy import pi, rot_ccw_axis3
A rotation of pi/3 (60 degrees):
>>> theta = pi/3
>>> rot_ccw_axis3(theta)
Matrix([
[ 1/2, -sqrt(3)/2, 0],
[sqrt(3)/2, 1/2, 0],
[ 0, 0, 1]])
If we rotate by pi/2 (90 degrees):
>>> rot_ccw_axis3(pi/2)
Matrix([
[0, -1, 0],
[1, 0, 0],
[0, 0, 1]])
See Also
========
rot_givens: Returns a Givens rotation matrix (generalized rotation for
any number of dimensions)
rot_axis3: Returns a rotation matrix for a rotation of theta (in radians)
about the 3-axis (clockwise around the z axis)
rot_ccw_axis1: Returns a rotation matrix for a rotation of theta (in radians)
about the 1-axis (counterclockwise around the x axis)
rot_ccw_axis2: Returns a rotation matrix for a rotation of theta (in radians)
about the 2-axis (counterclockwise around the y axis)
"""
return rot_givens(1, 0, theta, dim=3)
def rot_ccw_axis2(theta):
r"""Returns a rotation matrix for a rotation of theta (in radians)
about the 2-axis.
Explanation
===========
For a right-handed coordinate system, this corresponds to a
counterclockwise rotation around the `y`-axis, given by:
.. math::
R = \begin{bmatrix}
\cos(\theta) & 0 & \sin(\theta) \\
0 & 1 & 0 \\
-\sin(\theta) & 0 & \cos(\theta)
\end{bmatrix}
Examples
========
>>> from sympy import pi, rot_ccw_axis2
A rotation of pi/3 (60 degrees):
>>> theta = pi/3
>>> rot_ccw_axis2(theta)
Matrix([
[ 1/2, 0, sqrt(3)/2],
[ 0, 1, 0],
[-sqrt(3)/2, 0, 1/2]])
If we rotate by pi/2 (90 degrees):
>>> rot_ccw_axis2(pi/2)
Matrix([
[ 0, 0, 1],
[ 0, 1, 0],
[-1, 0, 0]])
See Also
========
rot_givens: Returns a Givens rotation matrix (generalized rotation for
any number of dimensions)
rot_axis2: Returns a rotation matrix for a rotation of theta (in radians)
about the 2-axis (clockwise around the y axis)
rot_ccw_axis1: Returns a rotation matrix for a rotation of theta (in radians)
about the 1-axis (counterclockwise around the x axis)
rot_ccw_axis3: Returns a rotation matrix for a rotation of theta (in radians)
about the 3-axis (counterclockwise around the z axis)
"""
return rot_givens(0, 2, theta, dim=3)
def rot_ccw_axis1(theta):
r"""Returns a rotation matrix for a rotation of theta (in radians)
about the 1-axis.
Explanation
===========
For a right-handed coordinate system, this corresponds to a
counterclockwise rotation around the `x`-axis, given by:
.. math::
R = \begin{bmatrix}
1 & 0 & 0 \\
0 & \cos(\theta) & -\sin(\theta) \\
0 & \sin(\theta) & \cos(\theta)
\end{bmatrix}
Examples
========
>>> from sympy import pi, rot_ccw_axis1
A rotation of pi/3 (60 degrees):
>>> theta = pi/3
>>> rot_ccw_axis1(theta)
Matrix([
[1, 0, 0],
[0, 1/2, -sqrt(3)/2],
[0, sqrt(3)/2, 1/2]])
If we rotate by pi/2 (90 degrees):
>>> rot_ccw_axis1(pi/2)
Matrix([
[1, 0, 0],
[0, 0, -1],
[0, 1, 0]])
See Also
========
rot_givens: Returns a Givens rotation matrix (generalized rotation for
any number of dimensions)
rot_axis1: Returns a rotation matrix for a rotation of theta (in radians)
about the 1-axis (clockwise around the x axis)
rot_ccw_axis2: Returns a rotation matrix for a rotation of theta (in radians)
about the 2-axis (counterclockwise around the y axis)
rot_ccw_axis3: Returns a rotation matrix for a rotation of theta (in radians)
about the 3-axis (counterclockwise around the z axis)
"""
return rot_givens(2, 1, theta, dim=3)
@doctest_depends_on(modules=('numpy',))
def symarray(prefix, shape, **kwargs): # pragma: no cover
r"""Create a numpy ndarray of symbols (as an object array).
The created symbols are named ``prefix_i1_i2_``... You should thus provide a
non-empty prefix if you want your symbols to be unique for different output
arrays, as SymPy symbols with identical names are the same object.
Parameters
----------
prefix : string
A prefix prepended to the name of every symbol.
shape : int or tuple
Shape of the created array. If an int, the array is one-dimensional; for
more than one dimension the shape must be a tuple.
\*\*kwargs : dict
keyword arguments passed on to Symbol
Examples
========
These doctests require numpy.
>>> from sympy import symarray
>>> symarray('', 3)
[_0 _1 _2]
If you want multiple symarrays to contain distinct symbols, you *must*
provide unique prefixes:
>>> a = symarray('', 3)
>>> b = symarray('', 3)
>>> a[0] == b[0]
True
>>> a = symarray('a', 3)
>>> b = symarray('b', 3)
>>> a[0] == b[0]
False
Creating symarrays with a prefix:
>>> symarray('a', 3)
[a_0 a_1 a_2]
For more than one dimension, the shape must be given as a tuple:
>>> symarray('a', (2, 3))
[[a_0_0 a_0_1 a_0_2]
[a_1_0 a_1_1 a_1_2]]
>>> symarray('a', (2, 3, 2))
[[[a_0_0_0 a_0_0_1]
[a_0_1_0 a_0_1_1]
[a_0_2_0 a_0_2_1]]
<BLANKLINE>
[[a_1_0_0 a_1_0_1]
[a_1_1_0 a_1_1_1]
[a_1_2_0 a_1_2_1]]]
For setting assumptions of the underlying Symbols:
>>> [s.is_real for s in symarray('a', 2, real=True)]
[True, True]
"""
from numpy import empty, ndindex
arr = empty(shape, dtype=object)
for index in ndindex(shape):
arr[index] = Symbol('%s_%s' % (prefix, '_'.join(map(str, index))),
**kwargs)
return arr
###############
# Functions
###############
def casoratian(seqs, n, zero=True):
"""Given linear difference operator L of order 'k' and homogeneous
equation Ly = 0 we want to compute kernel of L, which is a set
of 'k' sequences: a(n), b(n), ... z(n).
Solutions of L are linearly independent iff their Casoratian,
denoted as C(a, b, ..., z), do not vanish for n = 0.
Casoratian is defined by k x k determinant::
+ a(n) b(n) . . . z(n) +
| a(n+1) b(n+1) . . . z(n+1) |
| . . . . |
| . . . . |
| . . . . |
+ a(n+k-1) b(n+k-1) . . . z(n+k-1) +
It proves very useful in rsolve_hyper() where it is applied
to a generating set of a recurrence to factor out linearly
dependent solutions and return a basis:
>>> from sympy import Symbol, casoratian, factorial
>>> n = Symbol('n', integer=True)
Exponential and factorial are linearly independent:
>>> casoratian([2**n, factorial(n)], n) != 0
True
"""
seqs = list(map(sympify, seqs))
if not zero:
f = lambda i, j: seqs[j].subs(n, n + i)
else:
f = lambda i, j: seqs[j].subs(n, i)
k = len(seqs)
return Matrix(k, k, f).det()
def eye(*args, **kwargs):
"""Create square identity matrix n x n
See Also
========
diag
zeros
ones
"""
return Matrix.eye(*args, **kwargs)
def diag(*values, strict=True, unpack=False, **kwargs):
"""Returns a matrix with the provided values placed on the
diagonal. If non-square matrices are included, they will
produce a block-diagonal matrix.
Examples
========
This version of diag is a thin wrapper to Matrix.diag that differs
in that it treats all lists like matrices -- even when a single list
is given. If this is not desired, either put a `*` before the list or
set `unpack=True`.
>>> from sympy import diag
>>> diag([1, 2, 3], unpack=True) # = diag(1,2,3) or diag(*[1,2,3])
Matrix([
[1, 0, 0],
[0, 2, 0],
[0, 0, 3]])
>>> diag([1, 2, 3]) # a column vector
Matrix([
[1],
[2],
[3]])
See Also
========
.matrixbase.MatrixBase.eye
.matrixbase.MatrixBase.diagonal
.matrixbase.MatrixBase.diag
.expressions.blockmatrix.BlockMatrix
"""
return Matrix.diag(*values, strict=strict, unpack=unpack, **kwargs)
def GramSchmidt(vlist, orthonormal=False):
"""Apply the Gram-Schmidt process to a set of vectors.
Parameters
==========
vlist : List of Matrix
Vectors to be orthogonalized for.
orthonormal : Bool, optional
If true, return an orthonormal basis.
Returns
=======
vlist : List of Matrix
Orthogonalized vectors
Notes
=====
This routine is mostly duplicate from ``Matrix.orthogonalize``,
except for some difference that this always raises error when
linearly dependent vectors are found, and the keyword ``normalize``
has been named as ``orthonormal`` in this function.
See Also
========
.matrixbase.MatrixBase.orthogonalize
References
==========
.. [1] https://en.wikipedia.org/wiki/Gram%E2%80%93Schmidt_process
"""
return MutableDenseMatrix.orthogonalize(
*vlist, normalize=orthonormal, rankcheck=True
)
def hessian(f, varlist, constraints=()):
"""Compute Hessian matrix for a function f wrt parameters in varlist
which may be given as a sequence or a row/column vector. A list of
constraints may optionally be given.
Examples
========
>>> from sympy import Function, hessian, pprint
>>> from sympy.abc import x, y
>>> f = Function('f')(x, y)
>>> g1 = Function('g')(x, y)
>>> g2 = x**2 + 3*y
>>> pprint(hessian(f, (x, y), [g1, g2]))
[ d d ]
[ 0 0 --(g(x, y)) --(g(x, y)) ]
[ dx dy ]
[ ]
[ 0 0 2*x 3 ]
[ ]
[ 2 2 ]
[d d d ]
[--(g(x, y)) 2*x ---(f(x, y)) -----(f(x, y))]
[dx 2 dy dx ]
[ dx ]
[ ]
[ 2 2 ]
[d d d ]
[--(g(x, y)) 3 -----(f(x, y)) ---(f(x, y)) ]
[dy dy dx 2 ]
[ dy ]
References
==========
.. [1] https://en.wikipedia.org/wiki/Hessian_matrix
See Also
========
sympy.matrices.matrixbase.MatrixBase.jacobian
wronskian
"""
# f is the expression representing a function f, return regular matrix
if isinstance(varlist, MatrixBase):
if 1 not in varlist.shape:
raise ShapeError("`varlist` must be a column or row vector.")
if varlist.cols == 1:
varlist = varlist.T
varlist = varlist.tolist()[0]
if is_sequence(varlist):
n = len(varlist)
if not n:
raise ShapeError("`len(varlist)` must not be zero.")
else:
raise ValueError("Improper variable list in hessian function")
if not getattr(f, 'diff'):
# check differentiability
raise ValueError("Function `f` (%s) is not differentiable" % f)
m = len(constraints)
N = m + n
out = zeros(N)
for k, g in enumerate(constraints):
if not getattr(g, 'diff'):
# check differentiability
raise ValueError("Function `f` (%s) is not differentiable" % f)
for i in range(n):
out[k, i + m] = g.diff(varlist[i])
for i in range(n):
for j in range(i, n):
out[i + m, j + m] = f.diff(varlist[i]).diff(varlist[j])
for i in range(N):
for j in range(i + 1, N):
out[j, i] = out[i, j]
return out
def jordan_cell(eigenval, n):
"""
Create a Jordan block:
Examples
========
>>> from sympy import jordan_cell
>>> from sympy.abc import x
>>> jordan_cell(x, 4)
Matrix([
[x, 1, 0, 0],
[0, x, 1, 0],
[0, 0, x, 1],
[0, 0, 0, x]])
"""
return Matrix.jordan_block(size=n, eigenvalue=eigenval)
def matrix_multiply_elementwise(A, B):
"""Return the Hadamard product (elementwise product) of A and B
>>> from sympy import Matrix, matrix_multiply_elementwise
>>> A = Matrix([[0, 1, 2], [3, 4, 5]])
>>> B = Matrix([[1, 10, 100], [100, 10, 1]])
>>> matrix_multiply_elementwise(A, B)
Matrix([
[ 0, 10, 200],
[300, 40, 5]])
See Also
========
sympy.matrices.matrixbase.MatrixBase.__mul__
"""
return A.multiply_elementwise(B)
def ones(*args, **kwargs):
"""Returns a matrix of ones with ``rows`` rows and ``cols`` columns;
if ``cols`` is omitted a square matrix will be returned.
See Also
========
zeros
eye
diag
"""
if 'c' in kwargs:
kwargs['cols'] = kwargs.pop('c')
return Matrix.ones(*args, **kwargs)
def randMatrix(r, c=None, min=0, max=99, seed=None, symmetric=False,
percent=100, prng=None):
"""Create random matrix with dimensions ``r`` x ``c``. If ``c`` is omitted
the matrix will be square. If ``symmetric`` is True the matrix must be
square. If ``percent`` is less than 100 then only approximately the given
percentage of elements will be non-zero.
The pseudo-random number generator used to generate matrix is chosen in the
following way.
* If ``prng`` is supplied, it will be used as random number generator.
It should be an instance of ``random.Random``, or at least have
``randint`` and ``shuffle`` methods with same signatures.
* if ``prng`` is not supplied but ``seed`` is supplied, then new
``random.Random`` with given ``seed`` will be created;
* otherwise, a new ``random.Random`` with default seed will be used.
Examples
========
>>> from sympy import randMatrix
>>> randMatrix(3) # doctest:+SKIP
[25, 45, 27]
[44, 54, 9]
[23, 96, 46]
>>> randMatrix(3, 2) # doctest:+SKIP
[87, 29]
[23, 37]
[90, 26]
>>> randMatrix(3, 3, 0, 2) # doctest:+SKIP
[0, 2, 0]
[2, 0, 1]
[0, 0, 1]
>>> randMatrix(3, symmetric=True) # doctest:+SKIP
[85, 26, 29]
[26, 71, 43]
[29, 43, 57]
>>> A = randMatrix(3, seed=1)
>>> B = randMatrix(3, seed=2)
>>> A == B
False
>>> A == randMatrix(3, seed=1)
True
>>> randMatrix(3, symmetric=True, percent=50) # doctest:+SKIP
[77, 70, 0],
[70, 0, 0],
[ 0, 0, 88]
"""
# Note that ``Random()`` is equivalent to ``Random(None)``
prng = prng or random.Random(seed)
if c is None:
c = r
if symmetric and r != c:
raise ValueError('For symmetric matrices, r must equal c, but %i != %i' % (r, c))
ij = range(r * c)
if percent != 100:
ij = prng.sample(ij, int(len(ij)*percent // 100))
m = zeros(r, c)
if not symmetric:
for ijk in ij:
i, j = divmod(ijk, c)
m[i, j] = prng.randint(min, max)
else:
for ijk in ij:
i, j = divmod(ijk, c)
if i <= j:
m[i, j] = m[j, i] = prng.randint(min, max)
return m
def wronskian(functions, var, method='bareiss'):
"""
Compute Wronskian for [] of functions
::
| f1 f2 ... fn |
| f1' f2' ... fn' |
| . . . . |
W(f1, ..., fn) = | . . . . |
| . . . . |
| (n) (n) (n) |
| D (f1) D (f2) ... D (fn) |
see: https://en.wikipedia.org/wiki/Wronskian
See Also
========
sympy.matrices.matrixbase.MatrixBase.jacobian
hessian
"""
functions = [sympify(f) for f in functions]
n = len(functions)
if n == 0:
return S.One
W = Matrix(n, n, lambda i, j: functions[i].diff(var, j))
return W.det(method)
def zeros(*args, **kwargs):
"""Returns a matrix of zeros with ``rows`` rows and ``cols`` columns;
if ``cols`` is omitted a square matrix will be returned.
See Also
========
ones
eye
diag
"""
if 'c' in kwargs:
kwargs['cols'] = kwargs.pop('c')
return Matrix.zeros(*args, **kwargs)
PK ]ZZZ�0���� �� sympy/matrices/determinant.pyfrom types import FunctionType
from sympy.core.cache import cacheit
from sympy.core.numbers import Float, Integer
from sympy.core.singleton import S
from sympy.core.symbol import uniquely_named_symbol
from sympy.core.mul import Mul
from sympy.polys import PurePoly, cancel
from sympy.functions.combinatorial.numbers import nC
from sympy.polys.matrices.domainmatrix import DomainMatrix
from sympy.polys.matrices.ddm import DDM
from .exceptions import NonSquareMatrixError
from .utilities import (
_get_intermediate_simp, _get_intermediate_simp_bool,
_iszero, _is_zero_after_expand_mul, _dotprodsimp, _simplify)
def _find_reasonable_pivot(col, iszerofunc=_iszero, simpfunc=_simplify):
""" Find the lowest index of an item in ``col`` that is
suitable for a pivot. If ``col`` consists only of
Floats, the pivot with the largest norm is returned.
Otherwise, the first element where ``iszerofunc`` returns
False is used. If ``iszerofunc`` does not return false,
items are simplified and retested until a suitable
pivot is found.
Returns a 4-tuple
(pivot_offset, pivot_val, assumed_nonzero, newly_determined)
where pivot_offset is the index of the pivot, pivot_val is
the (possibly simplified) value of the pivot, assumed_nonzero
is True if an assumption that the pivot was non-zero
was made without being proved, and newly_determined are
elements that were simplified during the process of pivot
finding."""
newly_determined = []
col = list(col)
# a column that contains a mix of floats and integers
# but at least one float is considered a numerical
# column, and so we do partial pivoting
if all(isinstance(x, (Float, Integer)) for x in col) and any(
isinstance(x, Float) for x in col):
col_abs = [abs(x) for x in col]
max_value = max(col_abs)
if iszerofunc(max_value):
# just because iszerofunc returned True, doesn't
# mean the value is numerically zero. Make sure
# to replace all entries with numerical zeros
if max_value != 0:
newly_determined = [(i, 0) for i, x in enumerate(col) if x != 0]
return (None, None, False, newly_determined)
index = col_abs.index(max_value)
return (index, col[index], False, newly_determined)
# PASS 1 (iszerofunc directly)
possible_zeros = []
for i, x in enumerate(col):
is_zero = iszerofunc(x)
# is someone wrote a custom iszerofunc, it may return
# BooleanFalse or BooleanTrue instead of True or False,
# so use == for comparison instead of `is`
if is_zero == False:
# we found something that is definitely not zero
return (i, x, False, newly_determined)
possible_zeros.append(is_zero)
# by this point, we've found no certain non-zeros
if all(possible_zeros):
# if everything is definitely zero, we have
# no pivot
return (None, None, False, newly_determined)
# PASS 2 (iszerofunc after simplify)
# we haven't found any for-sure non-zeros, so
# go through the elements iszerofunc couldn't
# make a determination about and opportunistically
# simplify to see if we find something
for i, x in enumerate(col):
if possible_zeros[i] is not None:
continue
simped = simpfunc(x)
is_zero = iszerofunc(simped)
if is_zero in (True, False):
newly_determined.append((i, simped))
if is_zero == False:
return (i, simped, False, newly_determined)
possible_zeros[i] = is_zero
# after simplifying, some things that were recognized
# as zeros might be zeros
if all(possible_zeros):
# if everything is definitely zero, we have
# no pivot
return (None, None, False, newly_determined)
# PASS 3 (.equals(0))
# some expressions fail to simplify to zero, but
# ``.equals(0)`` evaluates to True. As a last-ditch
# attempt, apply ``.equals`` to these expressions
for i, x in enumerate(col):
if possible_zeros[i] is not None:
continue
if x.equals(S.Zero):
# ``.iszero`` may return False with
# an implicit assumption (e.g., ``x.equals(0)``
# when ``x`` is a symbol), so only treat it
# as proved when ``.equals(0)`` returns True
possible_zeros[i] = True
newly_determined.append((i, S.Zero))
if all(possible_zeros):
return (None, None, False, newly_determined)
# at this point there is nothing that could definitely
# be a pivot. To maintain compatibility with existing
# behavior, we'll assume that an illdetermined thing is
# non-zero. We should probably raise a warning in this case
i = possible_zeros.index(None)
return (i, col[i], True, newly_determined)
def _find_reasonable_pivot_naive(col, iszerofunc=_iszero, simpfunc=None):
"""
Helper that computes the pivot value and location from a
sequence of contiguous matrix column elements. As a side effect
of the pivot search, this function may simplify some of the elements
of the input column. A list of these simplified entries and their
indices are also returned.
This function mimics the behavior of _find_reasonable_pivot(),
but does less work trying to determine if an indeterminate candidate
pivot simplifies to zero. This more naive approach can be much faster,
with the trade-off that it may erroneously return a pivot that is zero.
``col`` is a sequence of contiguous column entries to be searched for
a suitable pivot.
``iszerofunc`` is a callable that returns a Boolean that indicates
if its input is zero, or None if no such determination can be made.
``simpfunc`` is a callable that simplifies its input. It must return
its input if it does not simplify its input. Passing in
``simpfunc=None`` indicates that the pivot search should not attempt
to simplify any candidate pivots.
Returns a 4-tuple:
(pivot_offset, pivot_val, assumed_nonzero, newly_determined)
``pivot_offset`` is the sequence index of the pivot.
``pivot_val`` is the value of the pivot.
pivot_val and col[pivot_index] are equivalent, but will be different
when col[pivot_index] was simplified during the pivot search.
``assumed_nonzero`` is a boolean indicating if the pivot cannot be
guaranteed to be zero. If assumed_nonzero is true, then the pivot
may or may not be non-zero. If assumed_nonzero is false, then
the pivot is non-zero.
``newly_determined`` is a list of index-value pairs of pivot candidates
that were simplified during the pivot search.
"""
# indeterminates holds the index-value pairs of each pivot candidate
# that is neither zero or non-zero, as determined by iszerofunc().
# If iszerofunc() indicates that a candidate pivot is guaranteed
# non-zero, or that every candidate pivot is zero then the contents
# of indeterminates are unused.
# Otherwise, the only viable candidate pivots are symbolic.
# In this case, indeterminates will have at least one entry,
# and all but the first entry are ignored when simpfunc is None.
indeterminates = []
for i, col_val in enumerate(col):
col_val_is_zero = iszerofunc(col_val)
if col_val_is_zero == False:
# This pivot candidate is non-zero.
return i, col_val, False, []
elif col_val_is_zero is None:
# The candidate pivot's comparison with zero
# is indeterminate.
indeterminates.append((i, col_val))
if len(indeterminates) == 0:
# All candidate pivots are guaranteed to be zero, i.e. there is
# no pivot.
return None, None, False, []
if simpfunc is None:
# Caller did not pass in a simplification function that might
# determine if an indeterminate pivot candidate is guaranteed
# to be nonzero, so assume the first indeterminate candidate
# is non-zero.
return indeterminates[0][0], indeterminates[0][1], True, []
# newly_determined holds index-value pairs of candidate pivots
# that were simplified during the search for a non-zero pivot.
newly_determined = []
for i, col_val in indeterminates:
tmp_col_val = simpfunc(col_val)
if id(col_val) != id(tmp_col_val):
# simpfunc() simplified this candidate pivot.
newly_determined.append((i, tmp_col_val))
if iszerofunc(tmp_col_val) == False:
# Candidate pivot simplified to a guaranteed non-zero value.
return i, tmp_col_val, False, newly_determined
return indeterminates[0][0], indeterminates[0][1], True, newly_determined
# This functions is a candidate for caching if it gets implemented for matrices.
def _berkowitz_toeplitz_matrix(M):
"""Return (A,T) where T the Toeplitz matrix used in the Berkowitz algorithm
corresponding to ``M`` and A is the first principal submatrix.
"""
# the 0 x 0 case is trivial
if M.rows == 0 and M.cols == 0:
return M._new(1,1, [M.one])
#
# Partition M = [ a_11 R ]
# [ C A ]
#
a, R = M[0,0], M[0, 1:]
C, A = M[1:, 0], M[1:,1:]
#
# The Toeplitz matrix looks like
#
# [ 1 ]
# [ -a 1 ]
# [ -RC -a 1 ]
# [ -RAC -RC -a 1 ]
# [ -RA**2C -RAC -RC -a 1 ]
# etc.
# Compute the diagonal entries.
# Because multiplying matrix times vector is so much
# more efficient than matrix times matrix, recursively
# compute -R * A**n * C.
diags = [C]
for i in range(M.rows - 2):
diags.append(A.multiply(diags[i], dotprodsimp=None))
diags = [(-R).multiply(d, dotprodsimp=None)[0, 0] for d in diags]
diags = [M.one, -a] + diags
def entry(i,j):
if j > i:
return M.zero
return diags[i - j]
toeplitz = M._new(M.cols + 1, M.rows, entry)
return (A, toeplitz)
# This functions is a candidate for caching if it gets implemented for matrices.
def _berkowitz_vector(M):
""" Run the Berkowitz algorithm and return a vector whose entries
are the coefficients of the characteristic polynomial of ``M``.
Given N x N matrix, efficiently compute
coefficients of characteristic polynomials of ``M``
without division in the ground domain.
This method is particularly useful for computing determinant,
principal minors and characteristic polynomial when ``M``
has complicated coefficients e.g. polynomials. Semi-direct
usage of this algorithm is also important in computing
efficiently sub-resultant PRS.
Assuming that M is a square matrix of dimension N x N and
I is N x N identity matrix, then the Berkowitz vector is
an N x 1 vector whose entries are coefficients of the
polynomial
charpoly(M) = det(t*I - M)
As a consequence, all polynomials generated by Berkowitz
algorithm are monic.
For more information on the implemented algorithm refer to:
[1] S.J. Berkowitz, On computing the determinant in small
parallel time using a small number of processors, ACM,
Information Processing Letters 18, 1984, pp. 147-150
[2] M. Keber, Division-Free computation of sub-resultants
using Bezout matrices, Tech. Report MPI-I-2006-1-006,
Saarbrucken, 2006
"""
# handle the trivial cases
if M.rows == 0 and M.cols == 0:
return M._new(1, 1, [M.one])
elif M.rows == 1 and M.cols == 1:
return M._new(2, 1, [M.one, -M[0,0]])
submat, toeplitz = _berkowitz_toeplitz_matrix(M)
return toeplitz.multiply(_berkowitz_vector(submat), dotprodsimp=None)
def _adjugate(M, method="berkowitz"):
"""Returns the adjugate, or classical adjoint, of
a matrix. That is, the transpose of the matrix of cofactors.
https://en.wikipedia.org/wiki/Adjugate
Parameters
==========
method : string, optional
Method to use to find the cofactors, can be "bareiss", "berkowitz",
"bird", "laplace" or "lu".
Examples
========
>>> from sympy import Matrix
>>> M = Matrix([[1, 2], [3, 4]])
>>> M.adjugate()
Matrix([
[ 4, -2],
[-3, 1]])
See Also
========
cofactor_matrix
sympy.matrices.matrixbase.MatrixBase.transpose
"""
return M.cofactor_matrix(method=method).transpose()
# This functions is a candidate for caching if it gets implemented for matrices.
def _charpoly(M, x='lambda', simplify=_simplify):
"""Computes characteristic polynomial det(x*I - M) where I is
the identity matrix.
A PurePoly is returned, so using different variables for ``x`` does
not affect the comparison or the polynomials:
Parameters
==========
x : string, optional
Name for the "lambda" variable, defaults to "lambda".
simplify : function, optional
Simplification function to use on the characteristic polynomial
calculated. Defaults to ``simplify``.
Examples
========
>>> from sympy import Matrix
>>> from sympy.abc import x, y
>>> M = Matrix([[1, 3], [2, 0]])
>>> M.charpoly()
PurePoly(lambda**2 - lambda - 6, lambda, domain='ZZ')
>>> M.charpoly(x) == M.charpoly(y)
True
>>> M.charpoly(x) == M.charpoly(y)
True
Specifying ``x`` is optional; a symbol named ``lambda`` is used by
default (which looks good when pretty-printed in unicode):
>>> M.charpoly().as_expr()
lambda**2 - lambda - 6
And if ``x`` clashes with an existing symbol, underscores will
be prepended to the name to make it unique:
>>> M = Matrix([[1, 2], [x, 0]])
>>> M.charpoly(x).as_expr()
_x**2 - _x - 2*x
Whether you pass a symbol or not, the generator can be obtained
with the gen attribute since it may not be the same as the symbol
that was passed:
>>> M.charpoly(x).gen
_x
>>> M.charpoly(x).gen == x
False
Notes
=====
The Samuelson-Berkowitz algorithm is used to compute
the characteristic polynomial efficiently and without any
division operations. Thus the characteristic polynomial over any
commutative ring without zero divisors can be computed.
If the determinant det(x*I - M) can be found out easily as
in the case of an upper or a lower triangular matrix, then
instead of Samuelson-Berkowitz algorithm, eigenvalues are computed
and the characteristic polynomial with their help.
See Also
========
det
"""
if not M.is_square:
raise NonSquareMatrixError()
# Use DomainMatrix. We are already going to convert this to a Poly so there
# is no need to worry about expanding powers etc. Also since this algorithm
# does not require division or zero detection it is fine to use EX.
#
# M.to_DM() will fall back on EXRAW rather than EX. EXRAW is a lot faster
# for elementary arithmetic because it does not call cancel for each
# operation but it generates large unsimplified results that are slow in
# the subsequent call to simplify. Using EX instead is faster overall
# but at least in some cases EXRAW+simplify gives a simpler result so we
# preserve that existing behaviour of charpoly for now...
dM = M.to_DM()
K = dM.domain
cp = dM.charpoly()
x = uniquely_named_symbol(x, [M], modify=lambda s: '_' + s)
if K.is_EXRAW or simplify is not _simplify:
# XXX: Converting back to Expr is expensive. We only do it if the
# caller supplied a custom simplify function for backwards
# compatibility or otherwise if the domain was EX. For any other domain
# there should be no benefit in simplifying at this stage because Poly
# will put everything into canonical form anyway.
berk_vector = [K.to_sympy(c) for c in cp]
berk_vector = [simplify(a) for a in berk_vector]
p = PurePoly(berk_vector, x)
else:
# Convert from the list of domain elements directly to Poly.
p = PurePoly(cp, x, domain=K)
return p
def _cofactor(M, i, j, method="berkowitz"):
"""Calculate the cofactor of an element.
Parameters
==========
method : string, optional
Method to use to find the cofactors, can be "bareiss", "berkowitz",
"bird", "laplace" or "lu".
Examples
========
>>> from sympy import Matrix
>>> M = Matrix([[1, 2], [3, 4]])
>>> M.cofactor(0, 1)
-3
See Also
========
cofactor_matrix
minor
minor_submatrix
"""
if not M.is_square or M.rows < 1:
raise NonSquareMatrixError()
return S.NegativeOne**((i + j) % 2) * M.minor(i, j, method)
def _cofactor_matrix(M, method="berkowitz"):
"""Return a matrix containing the cofactor of each element.
Parameters
==========
method : string, optional
Method to use to find the cofactors, can be "bareiss", "berkowitz",
"bird", "laplace" or "lu".
Examples
========
>>> from sympy import Matrix
>>> M = Matrix([[1, 2], [3, 4]])
>>> M.cofactor_matrix()
Matrix([
[ 4, -3],
[-2, 1]])
See Also
========
cofactor
minor
minor_submatrix
"""
if not M.is_square:
raise NonSquareMatrixError()
return M._new(M.rows, M.cols,
lambda i, j: M.cofactor(i, j, method))
def _per(M):
"""Returns the permanent of a matrix. Unlike determinant,
permanent is defined for both square and non-square matrices.
For an m x n matrix, with m less than or equal to n,
it is given as the sum over the permutations s of size
less than or equal to m on [1, 2, . . . n] of the product
from i = 1 to m of M[i, s[i]]. Taking the transpose will
not affect the value of the permanent.
In the case of a square matrix, this is the same as the permutation
definition of the determinant, but it does not take the sign of the
permutation into account. Computing the permanent with this definition
is quite inefficient, so here the Ryser formula is used.
Examples
========
>>> from sympy import Matrix
>>> M = Matrix([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
>>> M.per()
450
>>> M = Matrix([1, 5, 7])
>>> M.per()
13
References
==========
.. [1] Prof. Frank Ben's notes: https://math.berkeley.edu/~bernd/ban275.pdf
.. [2] Wikipedia article on Permanent: https://en.wikipedia.org/wiki/Permanent_%28mathematics%29
.. [3] https://reference.wolfram.com/language/ref/Permanent.html
.. [4] Permanent of a rectangular matrix : https://arxiv.org/pdf/0904.3251.pdf
"""
import itertools
m, n = M.shape
if m > n:
M = M.T
m, n = n, m
s = list(range(n))
subsets = []
for i in range(1, m + 1):
subsets += list(map(list, itertools.combinations(s, i)))
perm = 0
for subset in subsets:
prod = 1
sub_len = len(subset)
for i in range(m):
prod *= sum(M[i, j] for j in subset)
perm += prod * S.NegativeOne**sub_len * nC(n - sub_len, m - sub_len)
perm *= S.NegativeOne**m
return perm.simplify()
def _det_DOM(M):
DOM = DomainMatrix.from_Matrix(M, field=True, extension=True)
K = DOM.domain
return K.to_sympy(DOM.det())
# This functions is a candidate for caching if it gets implemented for matrices.
def _det(M, method="bareiss", iszerofunc=None):
"""Computes the determinant of a matrix if ``M`` is a concrete matrix object
otherwise return an expressions ``Determinant(M)`` if ``M`` is a
``MatrixSymbol`` or other expression.
Parameters
==========
method : string, optional
Specifies the algorithm used for computing the matrix determinant.
If the matrix is at most 3x3, a hard-coded formula is used and the
specified method is ignored. Otherwise, it defaults to
``'bareiss'``.
Also, if the matrix is an upper or a lower triangular matrix, determinant
is computed by simple multiplication of diagonal elements, and the
specified method is ignored.
If it is set to ``'domain-ge'``, then Gaussian elimination method will
be used via using DomainMatrix.
If it is set to ``'bareiss'``, Bareiss' fraction-free algorithm will
be used.
If it is set to ``'berkowitz'``, Berkowitz' algorithm will be used.
If it is set to ``'bird'``, Bird's algorithm will be used [1]_.
If it is set to ``'laplace'``, Laplace's algorithm will be used.
Otherwise, if it is set to ``'lu'``, LU decomposition will be used.
.. note::
For backward compatibility, legacy keys like "bareis" and
"det_lu" can still be used to indicate the corresponding
methods.
And the keys are also case-insensitive for now. However, it is
suggested to use the precise keys for specifying the method.
iszerofunc : FunctionType or None, optional
If it is set to ``None``, it will be defaulted to ``_iszero`` if the
method is set to ``'bareiss'``, and ``_is_zero_after_expand_mul`` if
the method is set to ``'lu'``.
It can also accept any user-specified zero testing function, if it
is formatted as a function which accepts a single symbolic argument
and returns ``True`` if it is tested as zero and ``False`` if it
tested as non-zero, and also ``None`` if it is undecidable.
Returns
=======
det : Basic
Result of determinant.
Raises
======
ValueError
If unrecognized keys are given for ``method`` or ``iszerofunc``.
NonSquareMatrixError
If attempted to calculate determinant from a non-square matrix.
Examples
========
>>> from sympy import Matrix, eye, det
>>> I3 = eye(3)
>>> det(I3)
1
>>> M = Matrix([[1, 2], [3, 4]])
>>> det(M)
-2
>>> det(M) == M.det()
True
>>> M.det(method="domain-ge")
-2
References
==========
.. [1] Bird, R. S. (2011). A simple division-free algorithm for computing
determinants. Inf. Process. Lett., 111(21), 1072-1074. doi:
10.1016/j.ipl.2011.08.006
"""
# sanitize `method`
method = method.lower()
if method == "bareis":
method = "bareiss"
elif method == "det_lu":
method = "lu"
if method not in ("bareiss", "berkowitz", "lu", "domain-ge", "bird",
"laplace"):
raise ValueError("Determinant method '%s' unrecognized" % method)
if iszerofunc is None:
if method == "bareiss":
iszerofunc = _is_zero_after_expand_mul
elif method == "lu":
iszerofunc = _iszero
elif not isinstance(iszerofunc, FunctionType):
raise ValueError("Zero testing method '%s' unrecognized" % iszerofunc)
n = M.rows
if n == M.cols: # square check is done in individual method functions
if n == 0:
return M.one
elif n == 1:
return M[0, 0]
elif n == 2:
m = M[0, 0] * M[1, 1] - M[0, 1] * M[1, 0]
return _get_intermediate_simp(_dotprodsimp)(m)
elif n == 3:
m = (M[0, 0] * M[1, 1] * M[2, 2]
+ M[0, 1] * M[1, 2] * M[2, 0]
+ M[0, 2] * M[1, 0] * M[2, 1]
- M[0, 2] * M[1, 1] * M[2, 0]
- M[0, 0] * M[1, 2] * M[2, 1]
- M[0, 1] * M[1, 0] * M[2, 2])
return _get_intermediate_simp(_dotprodsimp)(m)
dets = []
for b in M.strongly_connected_components():
if method == "domain-ge": # uses DomainMatrix to evaluate determinant
det = _det_DOM(M[b, b])
elif method == "bareiss":
det = M[b, b]._eval_det_bareiss(iszerofunc=iszerofunc)
elif method == "berkowitz":
det = M[b, b]._eval_det_berkowitz()
elif method == "lu":
det = M[b, b]._eval_det_lu(iszerofunc=iszerofunc)
elif method == "bird":
det = M[b, b]._eval_det_bird()
elif method == "laplace":
det = M[b, b]._eval_det_laplace()
dets.append(det)
return Mul(*dets)
# This functions is a candidate for caching if it gets implemented for matrices.
def _det_bareiss(M, iszerofunc=_is_zero_after_expand_mul):
"""Compute matrix determinant using Bareiss' fraction-free
algorithm which is an extension of the well known Gaussian
elimination method. This approach is best suited for dense
symbolic matrices and will result in a determinant with
minimal number of fractions. It means that less term
rewriting is needed on resulting formulae.
Parameters
==========
iszerofunc : function, optional
The function to use to determine zeros when doing an LU decomposition.
Defaults to ``lambda x: x.is_zero``.
TODO: Implement algorithm for sparse matrices (SFF),
http://www.eecis.udel.edu/~saunders/papers/sffge/it5.ps.
"""
# Recursively implemented Bareiss' algorithm as per Deanna Richelle Leggett's
# thesis http://www.math.usm.edu/perry/Research/Thesis_DRL.pdf
def bareiss(mat, cumm=1):
if mat.rows == 0:
return mat.one
elif mat.rows == 1:
return mat[0, 0]
# find a pivot and extract the remaining matrix
# With the default iszerofunc, _find_reasonable_pivot slows down
# the computation by the factor of 2.5 in one test.
# Relevant issues: #10279 and #13877.
pivot_pos, pivot_val, _, _ = _find_reasonable_pivot(mat[:, 0], iszerofunc=iszerofunc)
if pivot_pos is None:
return mat.zero
# if we have a valid pivot, we'll do a "row swap", so keep the
# sign of the det
sign = (-1) ** (pivot_pos % 2)
# we want every row but the pivot row and every column
rows = [i for i in range(mat.rows) if i != pivot_pos]
cols = list(range(mat.cols))
tmp_mat = mat.extract(rows, cols)
def entry(i, j):
ret = (pivot_val*tmp_mat[i, j + 1] - mat[pivot_pos, j + 1]*tmp_mat[i, 0]) / cumm
if _get_intermediate_simp_bool(True):
return _dotprodsimp(ret)
elif not ret.is_Atom:
return cancel(ret)
return ret
return sign*bareiss(M._new(mat.rows - 1, mat.cols - 1, entry), pivot_val)
if not M.is_square:
raise NonSquareMatrixError()
if M.rows == 0:
return M.one
# sympy/matrices/tests/test_matrices.py contains a test that
# suggests that the determinant of a 0 x 0 matrix is one, by
# convention.
return bareiss(M)
def _det_berkowitz(M):
""" Use the Berkowitz algorithm to compute the determinant."""
if not M.is_square:
raise NonSquareMatrixError()
if M.rows == 0:
return M.one
# sympy/matrices/tests/test_matrices.py contains a test that
# suggests that the determinant of a 0 x 0 matrix is one, by
# convention.
berk_vector = _berkowitz_vector(M)
return (-1)**(len(berk_vector) - 1) * berk_vector[-1]
# This functions is a candidate for caching if it gets implemented for matrices.
def _det_LU(M, iszerofunc=_iszero, simpfunc=None):
""" Computes the determinant of a matrix from its LU decomposition.
This function uses the LU decomposition computed by
LUDecomposition_Simple().
The keyword arguments iszerofunc and simpfunc are passed to
LUDecomposition_Simple().
iszerofunc is a callable that returns a boolean indicating if its
input is zero, or None if it cannot make the determination.
simpfunc is a callable that simplifies its input.
The default is simpfunc=None, which indicate that the pivot search
algorithm should not attempt to simplify any candidate pivots.
If simpfunc fails to simplify its input, then it must return its input
instead of a copy.
Parameters
==========
iszerofunc : function, optional
The function to use to determine zeros when doing an LU decomposition.
Defaults to ``lambda x: x.is_zero``.
simpfunc : function, optional
The simplification function to use when looking for zeros for pivots.
"""
if not M.is_square:
raise NonSquareMatrixError()
if M.rows == 0:
return M.one
# sympy/matrices/tests/test_matrices.py contains a test that
# suggests that the determinant of a 0 x 0 matrix is one, by
# convention.
lu, row_swaps = M.LUdecomposition_Simple(iszerofunc=iszerofunc,
simpfunc=simpfunc)
# P*A = L*U => det(A) = det(L)*det(U)/det(P) = det(P)*det(U).
# Lower triangular factor L encoded in lu has unit diagonal => det(L) = 1.
# P is a permutation matrix => det(P) in {-1, 1} => 1/det(P) = det(P).
# LUdecomposition_Simple() returns a list of row exchange index pairs, rather
# than a permutation matrix, but det(P) = (-1)**len(row_swaps).
# Avoid forming the potentially time consuming product of U's diagonal entries
# if the product is zero.
# Bottom right entry of U is 0 => det(A) = 0.
# It may be impossible to determine if this entry of U is zero when it is symbolic.
if iszerofunc(lu[lu.rows-1, lu.rows-1]):
return M.zero
# Compute det(P)
det = -M.one if len(row_swaps)%2 else M.one
# Compute det(U) by calculating the product of U's diagonal entries.
# The upper triangular portion of lu is the upper triangular portion of the
# U factor in the LU decomposition.
for k in range(lu.rows):
det *= lu[k, k]
# return det(P)*det(U)
return det
@cacheit
def __det_laplace(M):
"""Compute the determinant of a matrix using Laplace expansion.
This is a recursive function, and it should not be called directly.
Use _det_laplace() instead. The reason for splitting this function
into two is to allow caching of determinants of submatrices. While
one could also define this function inside _det_laplace(), that
would remove the advantage of using caching in Cramer Solve.
"""
n = M.shape[0]
if n == 1:
return M[0]
elif n == 2:
return M[0, 0] * M[1, 1] - M[0, 1] * M[1, 0]
else:
return sum((-1) ** i * M[0, i] *
__det_laplace(M.minor_submatrix(0, i)) for i in range(n))
def _det_laplace(M):
"""Compute the determinant of a matrix using Laplace expansion.
While Laplace expansion is not the most efficient method of computing
a determinant, it is a simple one, and it has the advantage of
being division free. To improve efficiency, this function uses
caching to avoid recomputing determinants of submatrices.
"""
if not M.is_square:
raise NonSquareMatrixError()
if M.shape[0] == 0:
return M.one
# sympy/matrices/tests/test_matrices.py contains a test that
# suggests that the determinant of a 0 x 0 matrix is one, by
# convention.
return __det_laplace(M.as_immutable())
def _det_bird(M):
r"""Compute the determinant of a matrix using Bird's algorithm.
Bird's algorithm is a simple division-free algorithm for computing, which
is of lower order than the Laplace's algorithm. It is described in [1]_.
References
==========
.. [1] Bird, R. S. (2011). A simple division-free algorithm for computing
determinants. Inf. Process. Lett., 111(21), 1072-1074. doi:
10.1016/j.ipl.2011.08.006
"""
def mu(X):
n = X.shape[0]
zero = X.domain.zero
total = zero
diag_sums = [zero]
for i in reversed(range(1, n)):
total -= X[i][i]
diag_sums.append(total)
diag_sums = diag_sums[::-1]
elems = [[zero] * i + [diag_sums[i]] + X_i[i + 1:] for i, X_i in
enumerate(X)]
return DDM(elems, X.shape, X.domain)
Mddm = M._rep.to_ddm()
n = M.shape[0]
if n == 0:
return M.one
# sympy/matrices/tests/test_matrices.py contains a test that
# suggests that the determinant of a 0 x 0 matrix is one, by
# convention.
Fn1 = Mddm
for _ in range(n - 1):
Fn1 = mu(Fn1).matmul(Mddm)
detA = Fn1[0][0]
if n % 2 == 0:
detA = -detA
return Mddm.domain.to_sympy(detA)
def _minor(M, i, j, method="berkowitz"):
"""Return the (i,j) minor of ``M``. That is,
return the determinant of the matrix obtained by deleting
the `i`th row and `j`th column from ``M``.
Parameters
==========
i, j : int
The row and column to exclude to obtain the submatrix.
method : string, optional
Method to use to find the determinant of the submatrix, can be
"bareiss", "berkowitz", "bird", "laplace" or "lu".
Examples
========
>>> from sympy import Matrix
>>> M = Matrix([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
>>> M.minor(1, 1)
-12
See Also
========
minor_submatrix
cofactor
det
"""
if not M.is_square:
raise NonSquareMatrixError()
return M.minor_submatrix(i, j).det(method=method)
def _minor_submatrix(M, i, j):
"""Return the submatrix obtained by removing the `i`th row
and `j`th column from ``M`` (works with Pythonic negative indices).
Parameters
==========
i, j : int
The row and column to exclude to obtain the submatrix.
Examples
========
>>> from sympy import Matrix
>>> M = Matrix([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
>>> M.minor_submatrix(1, 1)
Matrix([
[1, 3],
[7, 9]])
See Also
========
minor
cofactor
"""
if i < 0:
i += M.rows
if j < 0:
j += M.cols
if not 0 <= i < M.rows or not 0 <= j < M.cols:
raise ValueError("`i` and `j` must satisfy 0 <= i < ``M.rows`` "
"(%d)" % M.rows + "and 0 <= j < ``M.cols`` (%d)." % M.cols)
rows = [a for a in range(M.rows) if a != i]
cols = [a for a in range(M.cols) if a != j]
return M.extract(rows, cols)
PK ]ZZZk�� �� sympy/matrices/eigen.pyfrom types import FunctionType
from collections import Counter
from mpmath import mp, workprec
from mpmath.libmp.libmpf import prec_to_dps
from sympy.core.sorting import default_sort_key
from sympy.core.evalf import DEFAULT_MAXPREC, PrecisionExhausted
from sympy.core.logic import fuzzy_and, fuzzy_or
from sympy.core.numbers import Float
from sympy.core.sympify import _sympify
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.polys import roots, CRootOf, ZZ, QQ, EX
from sympy.polys.matrices import DomainMatrix
from sympy.polys.matrices.eigen import dom_eigenvects, dom_eigenvects_to_sympy
from sympy.polys.polytools import gcd
from .exceptions import MatrixError, NonSquareMatrixError
from .determinant import _find_reasonable_pivot
from .utilities import _iszero, _simplify
__doctest_requires__ = {
('_is_indefinite',
'_is_negative_definite',
'_is_negative_semidefinite',
'_is_positive_definite',
'_is_positive_semidefinite'): ['matplotlib'],
}
def _eigenvals_eigenvects_mpmath(M):
norm2 = lambda v: mp.sqrt(sum(i**2 for i in v))
v1 = None
prec = max(x._prec for x in M.atoms(Float))
eps = 2**-prec
while prec < DEFAULT_MAXPREC:
with workprec(prec):
A = mp.matrix(M.evalf(n=prec_to_dps(prec)))
E, ER = mp.eig(A)
v2 = norm2([i for e in E for i in (mp.re(e), mp.im(e))])
if v1 is not None and mp.fabs(v1 - v2) < eps:
return E, ER
v1 = v2
prec *= 2
# we get here because the next step would have taken us
# past MAXPREC or because we never took a step; in case
# of the latter, we refuse to send back a solution since
# it would not have been verified; we also resist taking
# a small step to arrive exactly at MAXPREC since then
# the two calculations might be artificially close.
raise PrecisionExhausted
def _eigenvals_mpmath(M, multiple=False):
"""Compute eigenvalues using mpmath"""
E, _ = _eigenvals_eigenvects_mpmath(M)
result = [_sympify(x) for x in E]
if multiple:
return result
return dict(Counter(result))
def _eigenvects_mpmath(M):
E, ER = _eigenvals_eigenvects_mpmath(M)
result = []
for i in range(M.rows):
eigenval = _sympify(E[i])
eigenvect = _sympify(ER[:, i])
result.append((eigenval, 1, [eigenvect]))
return result
# This function is a candidate for caching if it gets implemented for matrices.
def _eigenvals(
M, error_when_incomplete=True, *, simplify=False, multiple=False,
rational=False, **flags):
r"""Compute eigenvalues of the matrix.
Parameters
==========
error_when_incomplete : bool, optional
If it is set to ``True``, it will raise an error if not all
eigenvalues are computed. This is caused by ``roots`` not returning
a full list of eigenvalues.
simplify : bool or function, optional
If it is set to ``True``, it attempts to return the most
simplified form of expressions returned by applying default
simplification method in every routine.
If it is set to ``False``, it will skip simplification in this
particular routine to save computation resources.
If a function is passed to, it will attempt to apply
the particular function as simplification method.
rational : bool, optional
If it is set to ``True``, every floating point numbers would be
replaced with rationals before computation. It can solve some
issues of ``roots`` routine not working well with floats.
multiple : bool, optional
If it is set to ``True``, the result will be in the form of a
list.
If it is set to ``False``, the result will be in the form of a
dictionary.
Returns
=======
eigs : list or dict
Eigenvalues of a matrix. The return format would be specified by
the key ``multiple``.
Raises
======
MatrixError
If not enough roots had got computed.
NonSquareMatrixError
If attempted to compute eigenvalues from a non-square matrix.
Examples
========
>>> from sympy import Matrix
>>> M = Matrix(3, 3, [0, 1, 1, 1, 0, 0, 1, 1, 1])
>>> M.eigenvals()
{-1: 1, 0: 1, 2: 1}
See Also
========
MatrixBase.charpoly
eigenvects
Notes
=====
Eigenvalues of a matrix $A$ can be computed by solving a matrix
equation $\det(A - \lambda I) = 0$
It's not always possible to return radical solutions for
eigenvalues for matrices larger than $4, 4$ shape due to
Abel-Ruffini theorem.
If there is no radical solution is found for the eigenvalue,
it may return eigenvalues in the form of
:class:`sympy.polys.rootoftools.ComplexRootOf`.
"""
if not M:
if multiple:
return []
return {}
if not M.is_square:
raise NonSquareMatrixError("{} must be a square matrix.".format(M))
if M._rep.domain not in (ZZ, QQ):
# Skip this check for ZZ/QQ because it can be slow
if all(x.is_number for x in M) and M.has(Float):
return _eigenvals_mpmath(M, multiple=multiple)
if rational:
from sympy.simplify import nsimplify
M = M.applyfunc(
lambda x: nsimplify(x, rational=True) if x.has(Float) else x)
if multiple:
return _eigenvals_list(
M, error_when_incomplete=error_when_incomplete, simplify=simplify,
**flags)
return _eigenvals_dict(
M, error_when_incomplete=error_when_incomplete, simplify=simplify,
**flags)
eigenvals_error_message = \
"It is not always possible to express the eigenvalues of a matrix " + \
"of size 5x5 or higher in radicals. " + \
"We have CRootOf, but domains other than the rationals are not " + \
"currently supported. " + \
"If there are no symbols in the matrix, " + \
"it should still be possible to compute numeric approximations " + \
"of the eigenvalues using " + \
"M.evalf().eigenvals() or M.charpoly().nroots()."
def _eigenvals_list(
M, error_when_incomplete=True, simplify=False, **flags):
iblocks = M.strongly_connected_components()
all_eigs = []
is_dom = M._rep.domain in (ZZ, QQ)
for b in iblocks:
# Fast path for a 1x1 block:
if is_dom and len(b) == 1:
index = b[0]
val = M[index, index]
all_eigs.append(val)
continue
block = M[b, b]
if isinstance(simplify, FunctionType):
charpoly = block.charpoly(simplify=simplify)
else:
charpoly = block.charpoly()
eigs = roots(charpoly, multiple=True, **flags)
if len(eigs) != block.rows:
try:
eigs = charpoly.all_roots(multiple=True)
except NotImplementedError:
if error_when_incomplete:
raise MatrixError(eigenvals_error_message)
else:
eigs = []
all_eigs += eigs
if not simplify:
return all_eigs
if not isinstance(simplify, FunctionType):
simplify = _simplify
return [simplify(value) for value in all_eigs]
def _eigenvals_dict(
M, error_when_incomplete=True, simplify=False, **flags):
iblocks = M.strongly_connected_components()
all_eigs = {}
is_dom = M._rep.domain in (ZZ, QQ)
for b in iblocks:
# Fast path for a 1x1 block:
if is_dom and len(b) == 1:
index = b[0]
val = M[index, index]
all_eigs[val] = all_eigs.get(val, 0) + 1
continue
block = M[b, b]
if isinstance(simplify, FunctionType):
charpoly = block.charpoly(simplify=simplify)
else:
charpoly = block.charpoly()
eigs = roots(charpoly, multiple=False, **flags)
if sum(eigs.values()) != block.rows:
try:
eigs = dict(charpoly.all_roots(multiple=False))
except NotImplementedError:
if error_when_incomplete:
raise MatrixError(eigenvals_error_message)
else:
eigs = {}
for k, v in eigs.items():
if k in all_eigs:
all_eigs[k] += v
else:
all_eigs[k] = v
if not simplify:
return all_eigs
if not isinstance(simplify, FunctionType):
simplify = _simplify
return {simplify(key): value for key, value in all_eigs.items()}
def _eigenspace(M, eigenval, iszerofunc=_iszero, simplify=False):
"""Get a basis for the eigenspace for a particular eigenvalue"""
m = M - M.eye(M.rows) * eigenval
ret = m.nullspace(iszerofunc=iszerofunc)
# The nullspace for a real eigenvalue should be non-trivial.
# If we didn't find an eigenvector, try once more a little harder
if len(ret) == 0 and simplify:
ret = m.nullspace(iszerofunc=iszerofunc, simplify=True)
if len(ret) == 0:
raise NotImplementedError(
"Can't evaluate eigenvector for eigenvalue {}".format(eigenval))
return ret
def _eigenvects_DOM(M, **kwargs):
DOM = DomainMatrix.from_Matrix(M, field=True, extension=True)
DOM = DOM.to_dense()
if DOM.domain != EX:
rational, algebraic = dom_eigenvects(DOM)
eigenvects = dom_eigenvects_to_sympy(
rational, algebraic, M.__class__, **kwargs)
eigenvects = sorted(eigenvects, key=lambda x: default_sort_key(x[0]))
return eigenvects
return None
def _eigenvects_sympy(M, iszerofunc, simplify=True, **flags):
eigenvals = M.eigenvals(rational=False, **flags)
# Make sure that we have all roots in radical form
for x in eigenvals:
if x.has(CRootOf):
raise MatrixError(
"Eigenvector computation is not implemented if the matrix have "
"eigenvalues in CRootOf form")
eigenvals = sorted(eigenvals.items(), key=default_sort_key)
ret = []
for val, mult in eigenvals:
vects = _eigenspace(M, val, iszerofunc=iszerofunc, simplify=simplify)
ret.append((val, mult, vects))
return ret
# This functions is a candidate for caching if it gets implemented for matrices.
def _eigenvects(M, error_when_incomplete=True, iszerofunc=_iszero, *, chop=False, **flags):
"""Compute eigenvectors of the matrix.
Parameters
==========
error_when_incomplete : bool, optional
Raise an error when not all eigenvalues are computed. This is
caused by ``roots`` not returning a full list of eigenvalues.
iszerofunc : function, optional
Specifies a zero testing function to be used in ``rref``.
Default value is ``_iszero``, which uses SymPy's naive and fast
default assumption handler.
It can also accept any user-specified zero testing function, if it
is formatted as a function which accepts a single symbolic argument
and returns ``True`` if it is tested as zero and ``False`` if it
is tested as non-zero, and ``None`` if it is undecidable.
simplify : bool or function, optional
If ``True``, ``as_content_primitive()`` will be used to tidy up
normalization artifacts.
It will also be used by the ``nullspace`` routine.
chop : bool or positive number, optional
If the matrix contains any Floats, they will be changed to Rationals
for computation purposes, but the answers will be returned after
being evaluated with evalf. The ``chop`` flag is passed to ``evalf``.
When ``chop=True`` a default precision will be used; a number will
be interpreted as the desired level of precision.
Returns
=======
ret : [(eigenval, multiplicity, eigenspace), ...]
A ragged list containing tuples of data obtained by ``eigenvals``
and ``nullspace``.
``eigenspace`` is a list containing the ``eigenvector`` for each
eigenvalue.
``eigenvector`` is a vector in the form of a ``Matrix``. e.g.
a vector of length 3 is returned as ``Matrix([a_1, a_2, a_3])``.
Raises
======
NotImplementedError
If failed to compute nullspace.
Examples
========
>>> from sympy import Matrix
>>> M = Matrix(3, 3, [0, 1, 1, 1, 0, 0, 1, 1, 1])
>>> M.eigenvects()
[(-1, 1, [Matrix([
[-1],
[ 1],
[ 0]])]), (0, 1, [Matrix([
[ 0],
[-1],
[ 1]])]), (2, 1, [Matrix([
[2/3],
[1/3],
[ 1]])])]
See Also
========
eigenvals
MatrixBase.nullspace
"""
simplify = flags.get('simplify', True)
primitive = flags.get('simplify', False)
flags.pop('simplify', None) # remove this if it's there
flags.pop('multiple', None) # remove this if it's there
if not isinstance(simplify, FunctionType):
simpfunc = _simplify if simplify else lambda x: x
has_floats = M.has(Float)
if has_floats:
if all(x.is_number for x in M):
return _eigenvects_mpmath(M)
from sympy.simplify import nsimplify
M = M.applyfunc(lambda x: nsimplify(x, rational=True))
ret = _eigenvects_DOM(M)
if ret is None:
ret = _eigenvects_sympy(M, iszerofunc, simplify=simplify, **flags)
if primitive:
# if the primitive flag is set, get rid of any common
# integer denominators
def denom_clean(l):
return [(v / gcd(list(v))).applyfunc(simpfunc) for v in l]
ret = [(val, mult, denom_clean(es)) for val, mult, es in ret]
if has_floats:
# if we had floats to start with, turn the eigenvectors to floats
ret = [(val.evalf(chop=chop), mult, [v.evalf(chop=chop) for v in es])
for val, mult, es in ret]
return ret
def _is_diagonalizable_with_eigen(M, reals_only=False):
"""See _is_diagonalizable. This function returns the bool along with the
eigenvectors to avoid calculating them again in functions like
``diagonalize``."""
if not M.is_square:
return False, []
eigenvecs = M.eigenvects(simplify=True)
for val, mult, basis in eigenvecs:
if reals_only and not val.is_real: # if we have a complex eigenvalue
return False, eigenvecs
if mult != len(basis): # if the geometric multiplicity doesn't equal the algebraic
return False, eigenvecs
return True, eigenvecs
def _is_diagonalizable(M, reals_only=False, **kwargs):
"""Returns ``True`` if a matrix is diagonalizable.
Parameters
==========
reals_only : bool, optional
If ``True``, it tests whether the matrix can be diagonalized
to contain only real numbers on the diagonal.
If ``False``, it tests whether the matrix can be diagonalized
at all, even with numbers that may not be real.
Examples
========
Example of a diagonalizable matrix:
>>> from sympy import Matrix
>>> M = Matrix([[1, 2, 0], [0, 3, 0], [2, -4, 2]])
>>> M.is_diagonalizable()
True
Example of a non-diagonalizable matrix:
>>> M = Matrix([[0, 1], [0, 0]])
>>> M.is_diagonalizable()
False
Example of a matrix that is diagonalized in terms of non-real entries:
>>> M = Matrix([[0, 1], [-1, 0]])
>>> M.is_diagonalizable(reals_only=False)
True
>>> M.is_diagonalizable(reals_only=True)
False
See Also
========
sympy.matrices.matrixbase.MatrixBase.is_diagonal
diagonalize
"""
if not M.is_square:
return False
if all(e.is_real for e in M) and M.is_symmetric():
return True
if all(e.is_complex for e in M) and M.is_hermitian:
return True
return _is_diagonalizable_with_eigen(M, reals_only=reals_only)[0]
#G&VL, Matrix Computations, Algo 5.4.2
def _householder_vector(x):
if not x.cols == 1:
raise ValueError("Input must be a column matrix")
v = x.copy()
v_plus = x.copy()
v_minus = x.copy()
q = x[0, 0] / abs(x[0, 0])
norm_x = x.norm()
v_plus[0, 0] = x[0, 0] + q * norm_x
v_minus[0, 0] = x[0, 0] - q * norm_x
if x[1:, 0].norm() == 0:
bet = 0
v[0, 0] = 1
else:
if v_plus.norm() <= v_minus.norm():
v = v_plus
else:
v = v_minus
v = v / v[0]
bet = 2 / (v.norm() ** 2)
return v, bet
def _bidiagonal_decmp_hholder(M):
m = M.rows
n = M.cols
A = M.as_mutable()
U, V = A.eye(m), A.eye(n)
for i in range(min(m, n)):
v, bet = _householder_vector(A[i:, i])
hh_mat = A.eye(m - i) - bet * v * v.H
A[i:, i:] = hh_mat * A[i:, i:]
temp = A.eye(m)
temp[i:, i:] = hh_mat
U = U * temp
if i + 1 <= n - 2:
v, bet = _householder_vector(A[i, i+1:].T)
hh_mat = A.eye(n - i - 1) - bet * v * v.H
A[i:, i+1:] = A[i:, i+1:] * hh_mat
temp = A.eye(n)
temp[i+1:, i+1:] = hh_mat
V = temp * V
return U, A, V
def _eval_bidiag_hholder(M):
m = M.rows
n = M.cols
A = M.as_mutable()
for i in range(min(m, n)):
v, bet = _householder_vector(A[i:, i])
hh_mat = A.eye(m-i) - bet * v * v.H
A[i:, i:] = hh_mat * A[i:, i:]
if i + 1 <= n - 2:
v, bet = _householder_vector(A[i, i+1:].T)
hh_mat = A.eye(n - i - 1) - bet * v * v.H
A[i:, i+1:] = A[i:, i+1:] * hh_mat
return A
def _bidiagonal_decomposition(M, upper=True):
"""
Returns $(U,B,V.H)$ for
$$A = UBV^{H}$$
where $A$ is the input matrix, and $B$ is its Bidiagonalized form
Note: Bidiagonal Computation can hang for symbolic matrices.
Parameters
==========
upper : bool. Whether to do upper bidiagnalization or lower.
True for upper and False for lower.
References
==========
.. [1] Algorithm 5.4.2, Matrix computations by Golub and Van Loan, 4th edition
.. [2] Complex Matrix Bidiagonalization, https://github.com/vslobody/Householder-Bidiagonalization
"""
if not isinstance(upper, bool):
raise ValueError("upper must be a boolean")
if upper:
return _bidiagonal_decmp_hholder(M)
X = _bidiagonal_decmp_hholder(M.H)
return X[2].H, X[1].H, X[0].H
def _bidiagonalize(M, upper=True):
"""
Returns $B$, the Bidiagonalized form of the input matrix.
Note: Bidiagonal Computation can hang for symbolic matrices.
Parameters
==========
upper : bool. Whether to do upper bidiagnalization or lower.
True for upper and False for lower.
References
==========
.. [1] Algorithm 5.4.2, Matrix computations by Golub and Van Loan, 4th edition
.. [2] Complex Matrix Bidiagonalization : https://github.com/vslobody/Householder-Bidiagonalization
"""
if not isinstance(upper, bool):
raise ValueError("upper must be a boolean")
if upper:
return _eval_bidiag_hholder(M)
return _eval_bidiag_hholder(M.H).H
def _diagonalize(M, reals_only=False, sort=False, normalize=False):
"""
Return (P, D), where D is diagonal and
D = P^-1 * M * P
where M is current matrix.
Parameters
==========
reals_only : bool. Whether to throw an error if complex numbers are need
to diagonalize. (Default: False)
sort : bool. Sort the eigenvalues along the diagonal. (Default: False)
normalize : bool. If True, normalize the columns of P. (Default: False)
Examples
========
>>> from sympy import Matrix
>>> M = Matrix(3, 3, [1, 2, 0, 0, 3, 0, 2, -4, 2])
>>> M
Matrix([
[1, 2, 0],
[0, 3, 0],
[2, -4, 2]])
>>> (P, D) = M.diagonalize()
>>> D
Matrix([
[1, 0, 0],
[0, 2, 0],
[0, 0, 3]])
>>> P
Matrix([
[-1, 0, -1],
[ 0, 0, -1],
[ 2, 1, 2]])
>>> P.inv() * M * P
Matrix([
[1, 0, 0],
[0, 2, 0],
[0, 0, 3]])
See Also
========
sympy.matrices.matrixbase.MatrixBase.is_diagonal
is_diagonalizable
"""
if not M.is_square:
raise NonSquareMatrixError()
is_diagonalizable, eigenvecs = _is_diagonalizable_with_eigen(M,
reals_only=reals_only)
if not is_diagonalizable:
raise MatrixError("Matrix is not diagonalizable")
if sort:
eigenvecs = sorted(eigenvecs, key=default_sort_key)
p_cols, diag = [], []
for val, mult, basis in eigenvecs:
diag += [val] * mult
p_cols += basis
if normalize:
p_cols = [v / v.norm() for v in p_cols]
return M.hstack(*p_cols), M.diag(*diag)
def _fuzzy_positive_definite(M):
positive_diagonals = M._has_positive_diagonals()
if positive_diagonals is False:
return False
if positive_diagonals and M.is_strongly_diagonally_dominant:
return True
return None
def _fuzzy_positive_semidefinite(M):
nonnegative_diagonals = M._has_nonnegative_diagonals()
if nonnegative_diagonals is False:
return False
if nonnegative_diagonals and M.is_weakly_diagonally_dominant:
return True
return None
def _is_positive_definite(M):
if not M.is_hermitian:
if not M.is_square:
return False
M = M + M.H
fuzzy = _fuzzy_positive_definite(M)
if fuzzy is not None:
return fuzzy
return _is_positive_definite_GE(M)
def _is_positive_semidefinite(M):
if not M.is_hermitian:
if not M.is_square:
return False
M = M + M.H
fuzzy = _fuzzy_positive_semidefinite(M)
if fuzzy is not None:
return fuzzy
return _is_positive_semidefinite_cholesky(M)
def _is_negative_definite(M):
return _is_positive_definite(-M)
def _is_negative_semidefinite(M):
return _is_positive_semidefinite(-M)
def _is_indefinite(M):
if M.is_hermitian:
eigen = M.eigenvals()
args1 = [x.is_positive for x in eigen.keys()]
any_positive = fuzzy_or(args1)
args2 = [x.is_negative for x in eigen.keys()]
any_negative = fuzzy_or(args2)
return fuzzy_and([any_positive, any_negative])
elif M.is_square:
return (M + M.H).is_indefinite
return False
def _is_positive_definite_GE(M):
"""A division-free gaussian elimination method for testing
positive-definiteness."""
M = M.as_mutable()
size = M.rows
for i in range(size):
is_positive = M[i, i].is_positive
if is_positive is not True:
return is_positive
for j in range(i+1, size):
M[j, i+1:] = M[i, i] * M[j, i+1:] - M[j, i] * M[i, i+1:]
return True
def _is_positive_semidefinite_cholesky(M):
"""Uses Cholesky factorization with complete pivoting
References
==========
.. [1] http://eprints.ma.man.ac.uk/1199/1/covered/MIMS_ep2008_116.pdf
.. [2] https://www.value-at-risk.net/cholesky-factorization/
"""
M = M.as_mutable()
for k in range(M.rows):
diags = [M[i, i] for i in range(k, M.rows)]
pivot, pivot_val, nonzero, _ = _find_reasonable_pivot(diags)
if nonzero:
return None
if pivot is None:
for i in range(k+1, M.rows):
for j in range(k, M.cols):
iszero = M[i, j].is_zero
if iszero is None:
return None
elif iszero is False:
return False
return True
if M[k, k].is_negative or pivot_val.is_negative:
return False
elif not (M[k, k].is_nonnegative and pivot_val.is_nonnegative):
return None
if pivot > 0:
M.col_swap(k, k+pivot)
M.row_swap(k, k+pivot)
M[k, k] = sqrt(M[k, k])
M[k, k+1:] /= M[k, k]
M[k+1:, k+1:] -= M[k, k+1:].H * M[k, k+1:]
return M[-1, -1].is_nonnegative
_doc_positive_definite = \
r"""Finds out the definiteness of a matrix.
Explanation
===========
A square real matrix $A$ is:
- A positive definite matrix if $x^T A x > 0$
for all non-zero real vectors $x$.
- A positive semidefinite matrix if $x^T A x \geq 0$
for all non-zero real vectors $x$.
- A negative definite matrix if $x^T A x < 0$
for all non-zero real vectors $x$.
- A negative semidefinite matrix if $x^T A x \leq 0$
for all non-zero real vectors $x$.
- An indefinite matrix if there exists non-zero real vectors
$x, y$ with $x^T A x > 0 > y^T A y$.
A square complex matrix $A$ is:
- A positive definite matrix if $\text{re}(x^H A x) > 0$
for all non-zero complex vectors $x$.
- A positive semidefinite matrix if $\text{re}(x^H A x) \geq 0$
for all non-zero complex vectors $x$.
- A negative definite matrix if $\text{re}(x^H A x) < 0$
for all non-zero complex vectors $x$.
- A negative semidefinite matrix if $\text{re}(x^H A x) \leq 0$
for all non-zero complex vectors $x$.
- An indefinite matrix if there exists non-zero complex vectors
$x, y$ with $\text{re}(x^H A x) > 0 > \text{re}(y^H A y)$.
A matrix need not be symmetric or hermitian to be positive definite.
- A real non-symmetric matrix is positive definite if and only if
$\frac{A + A^T}{2}$ is positive definite.
- A complex non-hermitian matrix is positive definite if and only if
$\frac{A + A^H}{2}$ is positive definite.
And this extension can apply for all the definitions above.
However, for complex cases, you can restrict the definition of
$\text{re}(x^H A x) > 0$ to $x^H A x > 0$ and require the matrix
to be hermitian.
But we do not present this restriction for computation because you
can check ``M.is_hermitian`` independently with this and use
the same procedure.
Examples
========
An example of symmetric positive definite matrix:
.. plot::
:context: reset
:format: doctest
:include-source: True
>>> from sympy import Matrix, symbols
>>> from sympy.plotting import plot3d
>>> a, b = symbols('a b')
>>> x = Matrix([a, b])
>>> A = Matrix([[1, 0], [0, 1]])
>>> A.is_positive_definite
True
>>> A.is_positive_semidefinite
True
>>> p = plot3d((x.T*A*x)[0, 0], (a, -1, 1), (b, -1, 1))
An example of symmetric positive semidefinite matrix:
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> A = Matrix([[1, -1], [-1, 1]])
>>> A.is_positive_definite
False
>>> A.is_positive_semidefinite
True
>>> p = plot3d((x.T*A*x)[0, 0], (a, -1, 1), (b, -1, 1))
An example of symmetric negative definite matrix:
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> A = Matrix([[-1, 0], [0, -1]])
>>> A.is_negative_definite
True
>>> A.is_negative_semidefinite
True
>>> A.is_indefinite
False
>>> p = plot3d((x.T*A*x)[0, 0], (a, -1, 1), (b, -1, 1))
An example of symmetric indefinite matrix:
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> A = Matrix([[1, 2], [2, -1]])
>>> A.is_indefinite
True
>>> p = plot3d((x.T*A*x)[0, 0], (a, -1, 1), (b, -1, 1))
An example of non-symmetric positive definite matrix.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> A = Matrix([[1, 2], [-2, 1]])
>>> A.is_positive_definite
True
>>> A.is_positive_semidefinite
True
>>> p = plot3d((x.T*A*x)[0, 0], (a, -1, 1), (b, -1, 1))
Notes
=====
Although some people trivialize the definition of positive definite
matrices only for symmetric or hermitian matrices, this restriction
is not correct because it does not classify all instances of
positive definite matrices from the definition $x^T A x > 0$ or
$\text{re}(x^H A x) > 0$.
For instance, ``Matrix([[1, 2], [-2, 1]])`` presented in
the example above is an example of real positive definite matrix
that is not symmetric.
However, since the following formula holds true;
.. math::
\text{re}(x^H A x) > 0 \iff
\text{re}(x^H \frac{A + A^H}{2} x) > 0
We can classify all positive definite matrices that may or may not
be symmetric or hermitian by transforming the matrix to
$\frac{A + A^T}{2}$ or $\frac{A + A^H}{2}$
(which is guaranteed to be always real symmetric or complex
hermitian) and we can defer most of the studies to symmetric or
hermitian positive definite matrices.
But it is a different problem for the existence of Cholesky
decomposition. Because even though a non symmetric or a non
hermitian matrix can be positive definite, Cholesky or LDL
decomposition does not exist because the decompositions require the
matrix to be symmetric or hermitian.
References
==========
.. [1] https://en.wikipedia.org/wiki/Definiteness_of_a_matrix#Eigenvalues
.. [2] https://mathworld.wolfram.com/PositiveDefiniteMatrix.html
.. [3] Johnson, C. R. "Positive Definite Matrices." Amer.
Math. Monthly 77, 259-264 1970.
"""
_is_positive_definite.__doc__ = _doc_positive_definite
_is_positive_semidefinite.__doc__ = _doc_positive_definite
_is_negative_definite.__doc__ = _doc_positive_definite
_is_negative_semidefinite.__doc__ = _doc_positive_definite
_is_indefinite.__doc__ = _doc_positive_definite
def _jordan_form(M, calc_transform=True, *, chop=False):
"""Return $(P, J)$ where $J$ is a Jordan block
matrix and $P$ is a matrix such that $M = P J P^{-1}$
Parameters
==========
calc_transform : bool
If ``False``, then only $J$ is returned.
chop : bool
All matrices are converted to exact types when computing
eigenvalues and eigenvectors. As a result, there may be
approximation errors. If ``chop==True``, these errors
will be truncated.
Examples
========
>>> from sympy import Matrix
>>> M = Matrix([[ 6, 5, -2, -3], [-3, -1, 3, 3], [ 2, 1, -2, -3], [-1, 1, 5, 5]])
>>> P, J = M.jordan_form()
>>> J
Matrix([
[2, 1, 0, 0],
[0, 2, 0, 0],
[0, 0, 2, 1],
[0, 0, 0, 2]])
See Also
========
jordan_block
"""
if not M.is_square:
raise NonSquareMatrixError("Only square matrices have Jordan forms")
mat = M
has_floats = M.has(Float)
if has_floats:
try:
max_prec = max(term._prec for term in M.values() if isinstance(term, Float))
except ValueError:
# if no term in the matrix is explicitly a Float calling max()
# will throw a error so setting max_prec to default value of 53
max_prec = 53
# setting minimum max_dps to 15 to prevent loss of precision in
# matrix containing non evaluated expressions
max_dps = max(prec_to_dps(max_prec), 15)
def restore_floats(*args):
"""If ``has_floats`` is `True`, cast all ``args`` as
matrices of floats."""
if has_floats:
args = [m.evalf(n=max_dps, chop=chop) for m in args]
if len(args) == 1:
return args[0]
return args
# cache calculations for some speedup
mat_cache = {}
def eig_mat(val, pow):
"""Cache computations of ``(M - val*I)**pow`` for quick
retrieval"""
if (val, pow) in mat_cache:
return mat_cache[(val, pow)]
if (val, pow - 1) in mat_cache:
mat_cache[(val, pow)] = mat_cache[(val, pow - 1)].multiply(
mat_cache[(val, 1)], dotprodsimp=None)
else:
mat_cache[(val, pow)] = (mat - val*M.eye(M.rows)).pow(pow)
return mat_cache[(val, pow)]
# helper functions
def nullity_chain(val, algebraic_multiplicity):
"""Calculate the sequence [0, nullity(E), nullity(E**2), ...]
until it is constant where ``E = M - val*I``"""
# mat.rank() is faster than computing the null space,
# so use the rank-nullity theorem
cols = M.cols
ret = [0]
nullity = cols - eig_mat(val, 1).rank()
i = 2
while nullity != ret[-1]:
ret.append(nullity)
if nullity == algebraic_multiplicity:
break
nullity = cols - eig_mat(val, i).rank()
i += 1
# Due to issues like #7146 and #15872, SymPy sometimes
# gives the wrong rank. In this case, raise an error
# instead of returning an incorrect matrix
if nullity < ret[-1] or nullity > algebraic_multiplicity:
raise MatrixError(
"SymPy had encountered an inconsistent "
"result while computing Jordan block: "
"{}".format(M))
return ret
def blocks_from_nullity_chain(d):
"""Return a list of the size of each Jordan block.
If d_n is the nullity of E**n, then the number
of Jordan blocks of size n is
2*d_n - d_(n-1) - d_(n+1)"""
# d[0] is always the number of columns, so skip past it
mid = [2*d[n] - d[n - 1] - d[n + 1] for n in range(1, len(d) - 1)]
# d is assumed to plateau with "d[ len(d) ] == d[-1]", so
# 2*d_n - d_(n-1) - d_(n+1) == d_n - d_(n-1)
end = [d[-1] - d[-2]] if len(d) > 1 else [d[0]]
return mid + end
def pick_vec(small_basis, big_basis):
"""Picks a vector from big_basis that isn't in
the subspace spanned by small_basis"""
if len(small_basis) == 0:
return big_basis[0]
for v in big_basis:
_, pivots = M.hstack(*(small_basis + [v])).echelon_form(
with_pivots=True)
if pivots[-1] == len(small_basis):
return v
# roots doesn't like Floats, so replace them with Rationals
if has_floats:
from sympy.simplify import nsimplify
mat = mat.applyfunc(lambda x: nsimplify(x, rational=True))
# first calculate the jordan block structure
eigs = mat.eigenvals()
# Make sure that we have all roots in radical form
for x in eigs:
if x.has(CRootOf):
raise MatrixError(
"Jordan normal form is not implemented if the matrix have "
"eigenvalues in CRootOf form")
# most matrices have distinct eigenvalues
# and so are diagonalizable. In this case, don't
# do extra work!
if len(eigs.keys()) == mat.cols:
blocks = sorted(eigs.keys(), key=default_sort_key)
jordan_mat = mat.diag(*blocks)
if not calc_transform:
return restore_floats(jordan_mat)
jordan_basis = [eig_mat(eig, 1).nullspace()[0]
for eig in blocks]
basis_mat = mat.hstack(*jordan_basis)
return restore_floats(basis_mat, jordan_mat)
block_structure = []
for eig in sorted(eigs.keys(), key=default_sort_key):
algebraic_multiplicity = eigs[eig]
chain = nullity_chain(eig, algebraic_multiplicity)
block_sizes = blocks_from_nullity_chain(chain)
# if block_sizes = = [a, b, c, ...], then the number of
# Jordan blocks of size 1 is a, of size 2 is b, etc.
# create an array that has (eig, block_size) with one
# entry for each block
size_nums = [(i+1, num) for i, num in enumerate(block_sizes)]
# we expect larger Jordan blocks to come earlier
size_nums.reverse()
block_structure.extend(
[(eig, size) for size, num in size_nums for _ in range(num)])
jordan_form_size = sum(size for eig, size in block_structure)
if jordan_form_size != M.rows:
raise MatrixError(
"SymPy had encountered an inconsistent result while "
"computing Jordan block. : {}".format(M))
blocks = (mat.jordan_block(size=size, eigenvalue=eig) for eig, size in block_structure)
jordan_mat = mat.diag(*blocks)
if not calc_transform:
return restore_floats(jordan_mat)
# For each generalized eigenspace, calculate a basis.
# We start by looking for a vector in null( (A - eig*I)**n )
# which isn't in null( (A - eig*I)**(n-1) ) where n is
# the size of the Jordan block
#
# Ideally we'd just loop through block_structure and
# compute each generalized eigenspace. However, this
# causes a lot of unneeded computation. Instead, we
# go through the eigenvalues separately, since we know
# their generalized eigenspaces must have bases that
# are linearly independent.
jordan_basis = []
for eig in sorted(eigs.keys(), key=default_sort_key):
eig_basis = []
for block_eig, size in block_structure:
if block_eig != eig:
continue
null_big = (eig_mat(eig, size)).nullspace()
null_small = (eig_mat(eig, size - 1)).nullspace()
# we want to pick something that is in the big basis
# and not the small, but also something that is independent
# of any other generalized eigenvectors from a different
# generalized eigenspace sharing the same eigenvalue.
vec = pick_vec(null_small + eig_basis, null_big)
new_vecs = [eig_mat(eig, i).multiply(vec, dotprodsimp=None)
for i in range(size)]
eig_basis.extend(new_vecs)
jordan_basis.extend(reversed(new_vecs))
basis_mat = mat.hstack(*jordan_basis)
return restore_floats(basis_mat, jordan_mat)
def _left_eigenvects(M, **flags):
"""Returns left eigenvectors and eigenvalues.
This function returns the list of triples (eigenval, multiplicity,
basis) for the left eigenvectors. Options are the same as for
eigenvects(), i.e. the ``**flags`` arguments gets passed directly to
eigenvects().
Examples
========
>>> from sympy import Matrix
>>> M = Matrix([[0, 1, 1], [1, 0, 0], [1, 1, 1]])
>>> M.eigenvects()
[(-1, 1, [Matrix([
[-1],
[ 1],
[ 0]])]), (0, 1, [Matrix([
[ 0],
[-1],
[ 1]])]), (2, 1, [Matrix([
[2/3],
[1/3],
[ 1]])])]
>>> M.left_eigenvects()
[(-1, 1, [Matrix([[-2, 1, 1]])]), (0, 1, [Matrix([[-1, -1, 1]])]), (2,
1, [Matrix([[1, 1, 1]])])]
"""
eigs = M.transpose().eigenvects(**flags)
return [(val, mult, [l.transpose() for l in basis]) for val, mult, basis in eigs]
def _singular_values(M):
"""Compute the singular values of a Matrix
Examples
========
>>> from sympy import Matrix, Symbol
>>> x = Symbol('x', real=True)
>>> M = Matrix([[0, 1, 0], [0, x, 0], [-1, 0, 0]])
>>> M.singular_values()
[sqrt(x**2 + 1), 1, 0]
See Also
========
condition_number
"""
if M.rows >= M.cols:
valmultpairs = M.H.multiply(M).eigenvals()
else:
valmultpairs = M.multiply(M.H).eigenvals()
# Expands result from eigenvals into a simple list
vals = []
for k, v in valmultpairs.items():
vals += [sqrt(k)] * v # dangerous! same k in several spots!
# Pad with zeros if singular values are computed in reverse way,
# to give consistent format.
if len(vals) < M.cols:
vals += [M.zero] * (M.cols - len(vals))
# sort them in descending order
vals.sort(reverse=True, key=default_sort_key)
return vals
PK ]ZZZ�d#C� � sympy/matrices/exceptions.py"""
Exceptions raised by the matrix module.
"""
class MatrixError(Exception):
pass
class ShapeError(ValueError, MatrixError):
"""Wrong matrix shape"""
pass
class NonSquareMatrixError(ShapeError):
pass
class NonInvertibleMatrixError(ValueError, MatrixError):
"""The matrix in not invertible (division by multidimensional zero error)."""
pass
class NonPositiveDefiniteMatrixError(ValueError, MatrixError):
"""The matrix is not a positive-definite matrix."""
pass
PK ]ZZZp}J x# x# sympy/matrices/graph.pyfrom sympy.utilities.iterables import \
flatten, connected_components, strongly_connected_components
from .exceptions import NonSquareMatrixError
def _connected_components(M):
"""Returns the list of connected vertices of the graph when
a square matrix is viewed as a weighted graph.
Examples
========
>>> from sympy import Matrix
>>> A = Matrix([
... [66, 0, 0, 68, 0, 0, 0, 0, 67],
... [0, 55, 0, 0, 0, 0, 54, 53, 0],
... [0, 0, 0, 0, 1, 2, 0, 0, 0],
... [86, 0, 0, 88, 0, 0, 0, 0, 87],
... [0, 0, 10, 0, 11, 12, 0, 0, 0],
... [0, 0, 20, 0, 21, 22, 0, 0, 0],
... [0, 45, 0, 0, 0, 0, 44, 43, 0],
... [0, 35, 0, 0, 0, 0, 34, 33, 0],
... [76, 0, 0, 78, 0, 0, 0, 0, 77]])
>>> A.connected_components()
[[0, 3, 8], [1, 6, 7], [2, 4, 5]]
Notes
=====
Even if any symbolic elements of the matrix can be indeterminate
to be zero mathematically, this only takes the account of the
structural aspect of the matrix, so they will considered to be
nonzero.
"""
if not M.is_square:
raise NonSquareMatrixError
V = range(M.rows)
E = sorted(M.todok().keys())
return connected_components((V, E))
def _strongly_connected_components(M):
"""Returns the list of strongly connected vertices of the graph when
a square matrix is viewed as a weighted graph.
Examples
========
>>> from sympy import Matrix
>>> A = Matrix([
... [44, 0, 0, 0, 43, 0, 45, 0, 0],
... [0, 66, 62, 61, 0, 68, 0, 60, 67],
... [0, 0, 22, 21, 0, 0, 0, 20, 0],
... [0, 0, 12, 11, 0, 0, 0, 10, 0],
... [34, 0, 0, 0, 33, 0, 35, 0, 0],
... [0, 86, 82, 81, 0, 88, 0, 80, 87],
... [54, 0, 0, 0, 53, 0, 55, 0, 0],
... [0, 0, 2, 1, 0, 0, 0, 0, 0],
... [0, 76, 72, 71, 0, 78, 0, 70, 77]])
>>> A.strongly_connected_components()
[[0, 4, 6], [2, 3, 7], [1, 5, 8]]
"""
if not M.is_square:
raise NonSquareMatrixError
# RepMatrix uses the more efficient DomainMatrix.scc() method
rep = getattr(M, '_rep', None)
if rep is not None:
return rep.scc()
V = range(M.rows)
E = sorted(M.todok().keys())
return strongly_connected_components((V, E))
def _connected_components_decomposition(M):
"""Decomposes a square matrix into block diagonal form only
using the permutations.
Explanation
===========
The decomposition is in a form of $A = P^{-1} B P$ where $P$ is a
permutation matrix and $B$ is a block diagonal matrix.
Returns
=======
P, B : PermutationMatrix, BlockDiagMatrix
*P* is a permutation matrix for the similarity transform
as in the explanation. And *B* is the block diagonal matrix of
the result of the permutation.
If you would like to get the diagonal blocks from the
BlockDiagMatrix, see
:meth:`~sympy.matrices.expressions.blockmatrix.BlockDiagMatrix.get_diag_blocks`.
Examples
========
>>> from sympy import Matrix, pprint
>>> A = Matrix([
... [66, 0, 0, 68, 0, 0, 0, 0, 67],
... [0, 55, 0, 0, 0, 0, 54, 53, 0],
... [0, 0, 0, 0, 1, 2, 0, 0, 0],
... [86, 0, 0, 88, 0, 0, 0, 0, 87],
... [0, 0, 10, 0, 11, 12, 0, 0, 0],
... [0, 0, 20, 0, 21, 22, 0, 0, 0],
... [0, 45, 0, 0, 0, 0, 44, 43, 0],
... [0, 35, 0, 0, 0, 0, 34, 33, 0],
... [76, 0, 0, 78, 0, 0, 0, 0, 77]])
>>> P, B = A.connected_components_decomposition()
>>> pprint(P)
PermutationMatrix((1 3)(2 8 5 7 4 6))
>>> pprint(B)
[[66 68 67] ]
[[ ] ]
[[86 88 87] 0 0 ]
[[ ] ]
[[76 78 77] ]
[ ]
[ [55 54 53] ]
[ [ ] ]
[ 0 [45 44 43] 0 ]
[ [ ] ]
[ [35 34 33] ]
[ ]
[ [0 1 2 ]]
[ [ ]]
[ 0 0 [10 11 12]]
[ [ ]]
[ [20 21 22]]
>>> P = P.as_explicit()
>>> B = B.as_explicit()
>>> P.T*B*P == A
True
Notes
=====
This problem corresponds to the finding of the connected components
of a graph, when a matrix is viewed as a weighted graph.
"""
from sympy.combinatorics.permutations import Permutation
from sympy.matrices.expressions.blockmatrix import BlockDiagMatrix
from sympy.matrices.expressions.permutation import PermutationMatrix
iblocks = M.connected_components()
p = Permutation(flatten(iblocks))
P = PermutationMatrix(p)
blocks = []
for b in iblocks:
blocks.append(M[b, b])
B = BlockDiagMatrix(*blocks)
return P, B
def _strongly_connected_components_decomposition(M, lower=True):
"""Decomposes a square matrix into block triangular form only
using the permutations.
Explanation
===========
The decomposition is in a form of $A = P^{-1} B P$ where $P$ is a
permutation matrix and $B$ is a block diagonal matrix.
Parameters
==========
lower : bool
Makes $B$ lower block triangular when ``True``.
Otherwise, makes $B$ upper block triangular.
Returns
=======
P, B : PermutationMatrix, BlockMatrix
*P* is a permutation matrix for the similarity transform
as in the explanation. And *B* is the block triangular matrix of
the result of the permutation.
Examples
========
>>> from sympy import Matrix, pprint
>>> A = Matrix([
... [44, 0, 0, 0, 43, 0, 45, 0, 0],
... [0, 66, 62, 61, 0, 68, 0, 60, 67],
... [0, 0, 22, 21, 0, 0, 0, 20, 0],
... [0, 0, 12, 11, 0, 0, 0, 10, 0],
... [34, 0, 0, 0, 33, 0, 35, 0, 0],
... [0, 86, 82, 81, 0, 88, 0, 80, 87],
... [54, 0, 0, 0, 53, 0, 55, 0, 0],
... [0, 0, 2, 1, 0, 0, 0, 0, 0],
... [0, 76, 72, 71, 0, 78, 0, 70, 77]])
A lower block triangular decomposition:
>>> P, B = A.strongly_connected_components_decomposition()
>>> pprint(P)
PermutationMatrix((8)(1 4 3 2 6)(5 7))
>>> pprint(B)
[[44 43 45] [0 0 0] [0 0 0] ]
[[ ] [ ] [ ] ]
[[34 33 35] [0 0 0] [0 0 0] ]
[[ ] [ ] [ ] ]
[[54 53 55] [0 0 0] [0 0 0] ]
[ ]
[ [0 0 0] [22 21 20] [0 0 0] ]
[ [ ] [ ] [ ] ]
[ [0 0 0] [12 11 10] [0 0 0] ]
[ [ ] [ ] [ ] ]
[ [0 0 0] [2 1 0 ] [0 0 0] ]
[ ]
[ [0 0 0] [62 61 60] [66 68 67]]
[ [ ] [ ] [ ]]
[ [0 0 0] [82 81 80] [86 88 87]]
[ [ ] [ ] [ ]]
[ [0 0 0] [72 71 70] [76 78 77]]
>>> P = P.as_explicit()
>>> B = B.as_explicit()
>>> P.T * B * P == A
True
An upper block triangular decomposition:
>>> P, B = A.strongly_connected_components_decomposition(lower=False)
>>> pprint(P)
PermutationMatrix((0 1 5 7 4 3 2 8 6))
>>> pprint(B)
[[66 68 67] [62 61 60] [0 0 0] ]
[[ ] [ ] [ ] ]
[[86 88 87] [82 81 80] [0 0 0] ]
[[ ] [ ] [ ] ]
[[76 78 77] [72 71 70] [0 0 0] ]
[ ]
[ [0 0 0] [22 21 20] [0 0 0] ]
[ [ ] [ ] [ ] ]
[ [0 0 0] [12 11 10] [0 0 0] ]
[ [ ] [ ] [ ] ]
[ [0 0 0] [2 1 0 ] [0 0 0] ]
[ ]
[ [0 0 0] [0 0 0] [44 43 45]]
[ [ ] [ ] [ ]]
[ [0 0 0] [0 0 0] [34 33 35]]
[ [ ] [ ] [ ]]
[ [0 0 0] [0 0 0] [54 53 55]]
>>> P = P.as_explicit()
>>> B = B.as_explicit()
>>> P.T * B * P == A
True
"""
from sympy.combinatorics.permutations import Permutation
from sympy.matrices.expressions.blockmatrix import BlockMatrix
from sympy.matrices.expressions.permutation import PermutationMatrix
iblocks = M.strongly_connected_components()
if not lower:
iblocks = list(reversed(iblocks))
p = Permutation(flatten(iblocks))
P = PermutationMatrix(p)
rows = []
for a in iblocks:
cols = []
for b in iblocks:
cols.append(M[a, b])
rows.append(cols)
B = BlockMatrix(rows)
return P, B
PK ]ZZZ
�Zޚ � sympy/matrices/immutable.pyfrom mpmath.matrices.matrices import _matrix
from sympy.core import Basic, Dict, Tuple
from sympy.core.numbers import Integer
from sympy.core.cache import cacheit
from sympy.core.sympify import _sympy_converter as sympify_converter, _sympify
from sympy.matrices.dense import DenseMatrix
from sympy.matrices.expressions import MatrixExpr
from sympy.matrices.matrixbase import MatrixBase
from sympy.matrices.repmatrix import RepMatrix
from sympy.matrices.sparse import SparseRepMatrix
from sympy.multipledispatch import dispatch
def sympify_matrix(arg):
return arg.as_immutable()
sympify_converter[MatrixBase] = sympify_matrix
def sympify_mpmath_matrix(arg):
mat = [_sympify(x) for x in arg]
return ImmutableDenseMatrix(arg.rows, arg.cols, mat)
sympify_converter[_matrix] = sympify_mpmath_matrix
class ImmutableRepMatrix(RepMatrix, MatrixExpr): # type: ignore
"""Immutable matrix based on RepMatrix
Uses DomainMAtrix as the internal representation.
"""
#
# This is a subclass of RepMatrix that adds/overrides some methods to make
# the instances Basic and immutable. ImmutableRepMatrix is a superclass for
# both ImmutableDenseMatrix and ImmutableSparseMatrix.
#
def __new__(cls, *args, **kwargs):
return cls._new(*args, **kwargs)
__hash__ = MatrixExpr.__hash__
def copy(self):
return self
@property
def cols(self):
return self._cols
@property
def rows(self):
return self._rows
@property
def shape(self):
return self._rows, self._cols
def as_immutable(self):
return self
def _entry(self, i, j, **kwargs):
return self[i, j]
def __setitem__(self, *args):
raise TypeError("Cannot set values of {}".format(self.__class__))
def is_diagonalizable(self, reals_only=False, **kwargs):
return super().is_diagonalizable(
reals_only=reals_only, **kwargs)
is_diagonalizable.__doc__ = SparseRepMatrix.is_diagonalizable.__doc__
is_diagonalizable = cacheit(is_diagonalizable)
def analytic_func(self, f, x):
return self.as_mutable().analytic_func(f, x).as_immutable()
class ImmutableDenseMatrix(DenseMatrix, ImmutableRepMatrix): # type: ignore
"""Create an immutable version of a matrix.
Examples
========
>>> from sympy import eye, ImmutableMatrix
>>> ImmutableMatrix(eye(3))
Matrix([
[1, 0, 0],
[0, 1, 0],
[0, 0, 1]])
>>> _[0, 0] = 42
Traceback (most recent call last):
...
TypeError: Cannot set values of ImmutableDenseMatrix
"""
# MatrixExpr is set as NotIterable, but we want explicit matrices to be
# iterable
_iterable = True
_class_priority = 8
_op_priority = 10.001
@classmethod
def _new(cls, *args, **kwargs):
if len(args) == 1 and isinstance(args[0], ImmutableDenseMatrix):
return args[0]
if kwargs.get('copy', True) is False:
if len(args) != 3:
raise TypeError("'copy=False' requires a matrix be initialized as rows,cols,[list]")
rows, cols, flat_list = args
else:
rows, cols, flat_list = cls._handle_creation_inputs(*args, **kwargs)
flat_list = list(flat_list) # create a shallow copy
rep = cls._flat_list_to_DomainMatrix(rows, cols, flat_list)
return cls._fromrep(rep)
@classmethod
def _fromrep(cls, rep):
rows, cols = rep.shape
flat_list = rep.to_sympy().to_list_flat()
obj = Basic.__new__(cls,
Integer(rows),
Integer(cols),
Tuple(*flat_list, sympify=False))
obj._rows = rows
obj._cols = cols
obj._rep = rep
return obj
# make sure ImmutableDenseMatrix is aliased as ImmutableMatrix
ImmutableMatrix = ImmutableDenseMatrix
class ImmutableSparseMatrix(SparseRepMatrix, ImmutableRepMatrix): # type:ignore
"""Create an immutable version of a sparse matrix.
Examples
========
>>> from sympy import eye, ImmutableSparseMatrix
>>> ImmutableSparseMatrix(1, 1, {})
Matrix([[0]])
>>> ImmutableSparseMatrix(eye(3))
Matrix([
[1, 0, 0],
[0, 1, 0],
[0, 0, 1]])
>>> _[0, 0] = 42
Traceback (most recent call last):
...
TypeError: Cannot set values of ImmutableSparseMatrix
>>> _.shape
(3, 3)
"""
is_Matrix = True
_class_priority = 9
@classmethod
def _new(cls, *args, **kwargs):
rows, cols, smat = cls._handle_creation_inputs(*args, **kwargs)
rep = cls._smat_to_DomainMatrix(rows, cols, smat)
return cls._fromrep(rep)
@classmethod
def _fromrep(cls, rep):
rows, cols = rep.shape
smat = rep.to_sympy().to_dok()
obj = Basic.__new__(cls, Integer(rows), Integer(cols), Dict(smat))
obj._rows = rows
obj._cols = cols
obj._rep = rep
return obj
@dispatch(ImmutableDenseMatrix, ImmutableDenseMatrix)
def _eval_is_eq(lhs, rhs): # noqa:F811
"""Helper method for Equality with matrices.sympy.
Relational automatically converts matrices to ImmutableDenseMatrix
instances, so this method only applies here. Returns True if the
matrices are definitively the same, False if they are definitively
different, and None if undetermined (e.g. if they contain Symbols).
Returning None triggers default handling of Equalities.
"""
if lhs.shape != rhs.shape:
return False
return (lhs - rhs).is_zero_matrix
PK ]ZZZdm��n3 n3 sympy/matrices/inverse.pyfrom sympy.polys.matrices.exceptions import DMNonInvertibleMatrixError
from sympy.polys.domains import EX
from .exceptions import MatrixError, NonSquareMatrixError, NonInvertibleMatrixError
from .utilities import _iszero
def _pinv_full_rank(M):
"""Subroutine for full row or column rank matrices.
For full row rank matrices, inverse of ``A * A.H`` Exists.
For full column rank matrices, inverse of ``A.H * A`` Exists.
This routine can apply for both cases by checking the shape
and have small decision.
"""
if M.is_zero_matrix:
return M.H
if M.rows >= M.cols:
return M.H.multiply(M).inv().multiply(M.H)
else:
return M.H.multiply(M.multiply(M.H).inv())
def _pinv_rank_decomposition(M):
"""Subroutine for rank decomposition
With rank decompositions, `A` can be decomposed into two full-
rank matrices, and each matrix can take pseudoinverse
individually.
"""
if M.is_zero_matrix:
return M.H
B, C = M.rank_decomposition()
Bp = _pinv_full_rank(B)
Cp = _pinv_full_rank(C)
return Cp.multiply(Bp)
def _pinv_diagonalization(M):
"""Subroutine using diagonalization
This routine can sometimes fail if SymPy's eigenvalue
computation is not reliable.
"""
if M.is_zero_matrix:
return M.H
A = M
AH = M.H
try:
if M.rows >= M.cols:
P, D = AH.multiply(A).diagonalize(normalize=True)
D_pinv = D.applyfunc(lambda x: 0 if _iszero(x) else 1 / x)
return P.multiply(D_pinv).multiply(P.H).multiply(AH)
else:
P, D = A.multiply(AH).diagonalize(
normalize=True)
D_pinv = D.applyfunc(lambda x: 0 if _iszero(x) else 1 / x)
return AH.multiply(P).multiply(D_pinv).multiply(P.H)
except MatrixError:
raise NotImplementedError(
'pinv for rank-deficient matrices where '
'diagonalization of A.H*A fails is not supported yet.')
def _pinv(M, method='RD'):
"""Calculate the Moore-Penrose pseudoinverse of the matrix.
The Moore-Penrose pseudoinverse exists and is unique for any matrix.
If the matrix is invertible, the pseudoinverse is the same as the
inverse.
Parameters
==========
method : String, optional
Specifies the method for computing the pseudoinverse.
If ``'RD'``, Rank-Decomposition will be used.
If ``'ED'``, Diagonalization will be used.
Examples
========
Computing pseudoinverse by rank decomposition :
>>> from sympy import Matrix
>>> A = Matrix([[1, 2, 3], [4, 5, 6]])
>>> A.pinv()
Matrix([
[-17/18, 4/9],
[ -1/9, 1/9],
[ 13/18, -2/9]])
Computing pseudoinverse by diagonalization :
>>> B = A.pinv(method='ED')
>>> B.simplify()
>>> B
Matrix([
[-17/18, 4/9],
[ -1/9, 1/9],
[ 13/18, -2/9]])
See Also
========
inv
pinv_solve
References
==========
.. [1] https://en.wikipedia.org/wiki/Moore-Penrose_pseudoinverse
"""
# Trivial case: pseudoinverse of all-zero matrix is its transpose.
if M.is_zero_matrix:
return M.H
if method == 'RD':
return _pinv_rank_decomposition(M)
elif method == 'ED':
return _pinv_diagonalization(M)
else:
raise ValueError('invalid pinv method %s' % repr(method))
def _verify_invertible(M, iszerofunc=_iszero):
"""Initial check to see if a matrix is invertible. Raises or returns
determinant for use in _inv_ADJ."""
if not M.is_square:
raise NonSquareMatrixError("A Matrix must be square to invert.")
d = M.det(method='berkowitz')
zero = d.equals(0)
if zero is None: # if equals() can't decide, will rref be able to?
ok = M.rref(simplify=True)[0]
zero = any(iszerofunc(ok[j, j]) for j in range(ok.rows))
if zero:
raise NonInvertibleMatrixError("Matrix det == 0; not invertible.")
return d
def _inv_ADJ(M, iszerofunc=_iszero):
"""Calculates the inverse using the adjugate matrix and a determinant.
See Also
========
inv
inverse_GE
inverse_LU
inverse_CH
inverse_LDL
"""
d = _verify_invertible(M, iszerofunc=iszerofunc)
return M.adjugate() / d
def _inv_GE(M, iszerofunc=_iszero):
"""Calculates the inverse using Gaussian elimination.
See Also
========
inv
inverse_ADJ
inverse_LU
inverse_CH
inverse_LDL
"""
from .dense import Matrix
if not M.is_square:
raise NonSquareMatrixError("A Matrix must be square to invert.")
big = Matrix.hstack(M.as_mutable(), Matrix.eye(M.rows))
red = big.rref(iszerofunc=iszerofunc, simplify=True)[0]
if any(iszerofunc(red[j, j]) for j in range(red.rows)):
raise NonInvertibleMatrixError("Matrix det == 0; not invertible.")
return M._new(red[:, big.rows:])
def _inv_LU(M, iszerofunc=_iszero):
"""Calculates the inverse using LU decomposition.
See Also
========
inv
inverse_ADJ
inverse_GE
inverse_CH
inverse_LDL
"""
if not M.is_square:
raise NonSquareMatrixError("A Matrix must be square to invert.")
if M.free_symbols:
_verify_invertible(M, iszerofunc=iszerofunc)
return M.LUsolve(M.eye(M.rows), iszerofunc=_iszero)
def _inv_CH(M, iszerofunc=_iszero):
"""Calculates the inverse using cholesky decomposition.
See Also
========
inv
inverse_ADJ
inverse_GE
inverse_LU
inverse_LDL
"""
_verify_invertible(M, iszerofunc=iszerofunc)
return M.cholesky_solve(M.eye(M.rows))
def _inv_LDL(M, iszerofunc=_iszero):
"""Calculates the inverse using LDL decomposition.
See Also
========
inv
inverse_ADJ
inverse_GE
inverse_LU
inverse_CH
"""
_verify_invertible(M, iszerofunc=iszerofunc)
return M.LDLsolve(M.eye(M.rows))
def _inv_QR(M, iszerofunc=_iszero):
"""Calculates the inverse using QR decomposition.
See Also
========
inv
inverse_ADJ
inverse_GE
inverse_CH
inverse_LDL
"""
_verify_invertible(M, iszerofunc=iszerofunc)
return M.QRsolve(M.eye(M.rows))
def _try_DM(M, use_EX=False):
"""Try to convert a matrix to a ``DomainMatrix``."""
dM = M.to_DM()
K = dM.domain
# Return DomainMatrix if a domain is found. Only use EX if use_EX=True.
if not use_EX and K.is_EXRAW:
return None
elif K.is_EXRAW:
return dM.convert_to(EX)
else:
return dM
def _use_exact_domain(dom):
"""Check whether to convert to an exact domain."""
# DomainMatrix can handle RR and CC with partial pivoting. Other inexact
# domains like RR[a,b,...] can only be handled by converting to an exact
# domain like QQ[a,b,...]
if dom.is_RR or dom.is_CC:
return False
else:
return not dom.is_Exact
def _inv_DM(dM, cancel=True):
"""Calculates the inverse using ``DomainMatrix``.
See Also
========
inv
inverse_ADJ
inverse_GE
inverse_CH
inverse_LDL
sympy.polys.matrices.domainmatrix.DomainMatrix.inv
"""
m, n = dM.shape
dom = dM.domain
if m != n:
raise NonSquareMatrixError("A Matrix must be square to invert.")
# Convert RR[a,b,...] to QQ[a,b,...]
use_exact = _use_exact_domain(dom)
if use_exact:
dom_exact = dom.get_exact()
dM = dM.convert_to(dom_exact)
try:
dMi, den = dM.inv_den()
except DMNonInvertibleMatrixError:
raise NonInvertibleMatrixError("Matrix det == 0; not invertible.")
if use_exact:
dMi = dMi.convert_to(dom)
den = dom.convert_from(den, dom_exact)
if cancel:
# Convert to field and cancel with the denominator.
if not dMi.domain.is_Field:
dMi = dMi.to_field()
Mi = (dMi / den).to_Matrix()
else:
# Convert to Matrix and divide without cancelling
Mi = dMi.to_Matrix() / dMi.domain.to_sympy(den)
return Mi
def _inv_block(M, iszerofunc=_iszero):
"""Calculates the inverse using BLOCKWISE inversion.
See Also
========
inv
inverse_ADJ
inverse_GE
inverse_CH
inverse_LDL
"""
from sympy.matrices.expressions.blockmatrix import BlockMatrix
i = M.shape[0]
if i <= 20 :
return M.inv(method="LU", iszerofunc=_iszero)
A = M[:i // 2, :i //2]
B = M[:i // 2, i // 2:]
C = M[i // 2:, :i // 2]
D = M[i // 2:, i // 2:]
try:
D_inv = _inv_block(D)
except NonInvertibleMatrixError:
return M.inv(method="LU", iszerofunc=_iszero)
B_D_i = B*D_inv
BDC = B_D_i*C
A_n = A - BDC
try:
A_n = _inv_block(A_n)
except NonInvertibleMatrixError:
return M.inv(method="LU", iszerofunc=_iszero)
B_n = -A_n*B_D_i
dc = D_inv*C
C_n = -dc*A_n
D_n = D_inv + dc*-B_n
nn = BlockMatrix([[A_n, B_n], [C_n, D_n]]).as_explicit()
return nn
def _inv(M, method=None, iszerofunc=_iszero, try_block_diag=False):
"""
Return the inverse of a matrix using the method indicated. The default
is DM if a suitable domain is found or otherwise GE for dense matrices
LDL for sparse matrices.
Parameters
==========
method : ('DM', 'DMNC', 'GE', 'LU', 'ADJ', 'CH', 'LDL', 'QR')
iszerofunc : function, optional
Zero-testing function to use.
try_block_diag : bool, optional
If True then will try to form block diagonal matrices using the
method get_diag_blocks(), invert these individually, and then
reconstruct the full inverse matrix.
Examples
========
>>> from sympy import SparseMatrix, Matrix
>>> A = SparseMatrix([
... [ 2, -1, 0],
... [-1, 2, -1],
... [ 0, 0, 2]])
>>> A.inv('CH')
Matrix([
[2/3, 1/3, 1/6],
[1/3, 2/3, 1/3],
[ 0, 0, 1/2]])
>>> A.inv(method='LDL') # use of 'method=' is optional
Matrix([
[2/3, 1/3, 1/6],
[1/3, 2/3, 1/3],
[ 0, 0, 1/2]])
>>> A * _
Matrix([
[1, 0, 0],
[0, 1, 0],
[0, 0, 1]])
>>> A = Matrix(A)
>>> A.inv('CH')
Matrix([
[2/3, 1/3, 1/6],
[1/3, 2/3, 1/3],
[ 0, 0, 1/2]])
>>> A.inv('ADJ') == A.inv('GE') == A.inv('LU') == A.inv('CH') == A.inv('LDL') == A.inv('QR')
True
Notes
=====
According to the ``method`` keyword, it calls the appropriate method:
DM .... Use DomainMatrix ``inv_den`` method
DMNC .... Use DomainMatrix ``inv_den`` method without cancellation
GE .... inverse_GE(); default for dense matrices
LU .... inverse_LU()
ADJ ... inverse_ADJ()
CH ... inverse_CH()
LDL ... inverse_LDL(); default for sparse matrices
QR ... inverse_QR()
Note, the GE and LU methods may require the matrix to be simplified
before it is inverted in order to properly detect zeros during
pivoting. In difficult cases a custom zero detection function can
be provided by setting the ``iszerofunc`` argument to a function that
should return True if its argument is zero. The ADJ routine computes
the determinant and uses that to detect singular matrices in addition
to testing for zeros on the diagonal.
See Also
========
inverse_ADJ
inverse_GE
inverse_LU
inverse_CH
inverse_LDL
Raises
======
ValueError
If the determinant of the matrix is zero.
"""
from sympy.matrices import diag, SparseMatrix
if not M.is_square:
raise NonSquareMatrixError("A Matrix must be square to invert.")
if try_block_diag:
blocks = M.get_diag_blocks()
r = []
for block in blocks:
r.append(block.inv(method=method, iszerofunc=iszerofunc))
return diag(*r)
# Default: Use DomainMatrix if the domain is not EX.
# If DM is requested explicitly then use it even if the domain is EX.
if method is None and iszerofunc is _iszero:
dM = _try_DM(M, use_EX=False)
if dM is not None:
method = 'DM'
elif method in ("DM", "DMNC"):
dM = _try_DM(M, use_EX=True)
# A suitable domain was not found, fall back to GE for dense matrices
# and LDL for sparse matrices.
if method is None:
if isinstance(M, SparseMatrix):
method = 'LDL'
else:
method = 'GE'
if method == "DM":
rv = _inv_DM(dM)
elif method == "DMNC":
rv = _inv_DM(dM, cancel=False)
elif method == "GE":
rv = M.inverse_GE(iszerofunc=iszerofunc)
elif method == "LU":
rv = M.inverse_LU(iszerofunc=iszerofunc)
elif method == "ADJ":
rv = M.inverse_ADJ(iszerofunc=iszerofunc)
elif method == "CH":
rv = M.inverse_CH(iszerofunc=iszerofunc)
elif method == "LDL":
rv = M.inverse_LDL(iszerofunc=iszerofunc)
elif method == "QR":
rv = M.inverse_QR(iszerofunc=iszerofunc)
elif method == "BLOCK":
rv = M.inverse_BLOCK(iszerofunc=iszerofunc)
else:
raise ValueError("Inversion method unrecognized")
return M._new(rv)
PK ]ZZZ�y sympy/matrices/kind.py# sympy.matrices.kind
from sympy.core.kind import Kind, _NumberKind, NumberKind
from sympy.core.mul import Mul
class MatrixKind(Kind):
"""
Kind for all matrices in SymPy.
Basic class for this kind is ``MatrixBase`` and ``MatrixExpr``,
but any expression representing the matrix can have this.
Parameters
==========
element_kind : Kind
Kind of the element. Default is
:class:`sympy.core.kind.NumberKind`,
which means that the matrix contains only numbers.
Examples
========
Any instance of matrix class has kind ``MatrixKind``:
>>> from sympy import MatrixSymbol
>>> A = MatrixSymbol('A', 2, 2)
>>> A.kind
MatrixKind(NumberKind)
An expression representing a matrix may not be an instance of
the Matrix class, but it will have kind ``MatrixKind``:
>>> from sympy import MatrixExpr, Integral
>>> from sympy.abc import x
>>> intM = Integral(A, x)
>>> isinstance(intM, MatrixExpr)
False
>>> intM.kind
MatrixKind(NumberKind)
Use ``isinstance()`` to check for ``MatrixKind`` without specifying the
element kind. Use ``is`` to check the kind including the element kind:
>>> from sympy import Matrix
>>> from sympy.core import NumberKind
>>> from sympy.matrices import MatrixKind
>>> M = Matrix([1, 2])
>>> isinstance(M.kind, MatrixKind)
True
>>> M.kind is MatrixKind(NumberKind)
True
See Also
========
sympy.core.kind.NumberKind
sympy.core.kind.UndefinedKind
sympy.core.containers.TupleKind
sympy.sets.sets.SetKind
"""
def __new__(cls, element_kind=NumberKind):
obj = super().__new__(cls, element_kind)
obj.element_kind = element_kind
return obj
def __repr__(self):
return "MatrixKind(%s)" % self.element_kind
@Mul._kind_dispatcher.register(_NumberKind, MatrixKind)
def num_mat_mul(k1, k2):
"""
Return MatrixKind. The element kind is selected by recursive dispatching.
Do not need to dispatch in reversed order because KindDispatcher
searches for this automatically.
"""
# Deal with Mul._kind_dispatcher's commutativity
# XXX: this function is called with either k1 or k2 as MatrixKind because
# the Mul kind dispatcher is commutative. Maybe it shouldn't be. Need to
# swap the args here because NumberKind does not have an element_kind
# attribute.
if not isinstance(k2, MatrixKind):
k1, k2 = k2, k1
elemk = Mul._kind_dispatcher(k1, k2.element_kind)
return MatrixKind(elemk)
@Mul._kind_dispatcher.register(MatrixKind, MatrixKind)
def mat_mat_mul(k1, k2):
"""
Return MatrixKind. The element kind is selected by recursive dispatching.
"""
elemk = Mul._kind_dispatcher(k1.element_kind, k2.element_kind)
return MatrixKind(elemk)
PK ]ZZZ(\dR�[ �[ sympy/matrices/matrices.py#
# A module consisting of deprecated matrix classes. New code should not be
# added here.
#
from sympy.core.basic import Basic
from sympy.core.symbol import Dummy
from .common import MatrixCommon
from .exceptions import NonSquareMatrixError
from .utilities import _iszero, _is_zero_after_expand_mul, _simplify
from .determinant import (
_find_reasonable_pivot, _find_reasonable_pivot_naive,
_adjugate, _charpoly, _cofactor, _cofactor_matrix, _per,
_det, _det_bareiss, _det_berkowitz, _det_bird, _det_laplace, _det_LU,
_minor, _minor_submatrix)
from .reductions import _is_echelon, _echelon_form, _rank, _rref
from .subspaces import _columnspace, _nullspace, _rowspace, _orthogonalize
from .eigen import (
_eigenvals, _eigenvects,
_bidiagonalize, _bidiagonal_decomposition,
_is_diagonalizable, _diagonalize,
_is_positive_definite, _is_positive_semidefinite,
_is_negative_definite, _is_negative_semidefinite, _is_indefinite,
_jordan_form, _left_eigenvects, _singular_values)
# This class was previously defined in this module, but was moved to
# sympy.matrices.matrixbase. We import it here for backwards compatibility in
# case someone was importing it from here.
from .matrixbase import MatrixBase
__doctest_requires__ = {
('MatrixEigen.is_indefinite',
'MatrixEigen.is_negative_definite',
'MatrixEigen.is_negative_semidefinite',
'MatrixEigen.is_positive_definite',
'MatrixEigen.is_positive_semidefinite'): ['matplotlib'],
}
class MatrixDeterminant(MatrixCommon):
"""Provides basic matrix determinant operations. Should not be instantiated
directly. See ``determinant.py`` for their implementations."""
def _eval_det_bareiss(self, iszerofunc=_is_zero_after_expand_mul):
return _det_bareiss(self, iszerofunc=iszerofunc)
def _eval_det_berkowitz(self):
return _det_berkowitz(self)
def _eval_det_lu(self, iszerofunc=_iszero, simpfunc=None):
return _det_LU(self, iszerofunc=iszerofunc, simpfunc=simpfunc)
def _eval_det_bird(self):
return _det_bird(self)
def _eval_det_laplace(self):
return _det_laplace(self)
def _eval_determinant(self): # for expressions.determinant.Determinant
return _det(self)
def adjugate(self, method="berkowitz"):
return _adjugate(self, method=method)
def charpoly(self, x='lambda', simplify=_simplify):
return _charpoly(self, x=x, simplify=simplify)
def cofactor(self, i, j, method="berkowitz"):
return _cofactor(self, i, j, method=method)
def cofactor_matrix(self, method="berkowitz"):
return _cofactor_matrix(self, method=method)
def det(self, method="bareiss", iszerofunc=None):
return _det(self, method=method, iszerofunc=iszerofunc)
def per(self):
return _per(self)
def minor(self, i, j, method="berkowitz"):
return _minor(self, i, j, method=method)
def minor_submatrix(self, i, j):
return _minor_submatrix(self, i, j)
_find_reasonable_pivot.__doc__ = _find_reasonable_pivot.__doc__
_find_reasonable_pivot_naive.__doc__ = _find_reasonable_pivot_naive.__doc__
_eval_det_bareiss.__doc__ = _det_bareiss.__doc__
_eval_det_berkowitz.__doc__ = _det_berkowitz.__doc__
_eval_det_bird.__doc__ = _det_bird.__doc__
_eval_det_laplace.__doc__ = _det_laplace.__doc__
_eval_det_lu.__doc__ = _det_LU.__doc__
_eval_determinant.__doc__ = _det.__doc__
adjugate.__doc__ = _adjugate.__doc__
charpoly.__doc__ = _charpoly.__doc__
cofactor.__doc__ = _cofactor.__doc__
cofactor_matrix.__doc__ = _cofactor_matrix.__doc__
det.__doc__ = _det.__doc__
per.__doc__ = _per.__doc__
minor.__doc__ = _minor.__doc__
minor_submatrix.__doc__ = _minor_submatrix.__doc__
class MatrixReductions(MatrixDeterminant):
"""Provides basic matrix row/column operations. Should not be instantiated
directly. See ``reductions.py`` for some of their implementations."""
def echelon_form(self, iszerofunc=_iszero, simplify=False, with_pivots=False):
return _echelon_form(self, iszerofunc=iszerofunc, simplify=simplify,
with_pivots=with_pivots)
@property
def is_echelon(self):
return _is_echelon(self)
def rank(self, iszerofunc=_iszero, simplify=False):
return _rank(self, iszerofunc=iszerofunc, simplify=simplify)
def rref_rhs(self, rhs):
"""Return reduced row-echelon form of matrix, matrix showing
rhs after reduction steps. ``rhs`` must have the same number
of rows as ``self``.
Examples
========
>>> from sympy import Matrix, symbols
>>> r1, r2 = symbols('r1 r2')
>>> Matrix([[1, 1], [2, 1]]).rref_rhs(Matrix([r1, r2]))
(Matrix([
[1, 0],
[0, 1]]), Matrix([
[ -r1 + r2],
[2*r1 - r2]]))
"""
r, _ = _rref(self.hstack(self, self.eye(self.rows), rhs))
return r[:, :self.cols], r[:, -rhs.cols:]
def rref(self, iszerofunc=_iszero, simplify=False, pivots=True,
normalize_last=True):
return _rref(self, iszerofunc=iszerofunc, simplify=simplify,
pivots=pivots, normalize_last=normalize_last)
echelon_form.__doc__ = _echelon_form.__doc__
is_echelon.__doc__ = _is_echelon.__doc__
rank.__doc__ = _rank.__doc__
rref.__doc__ = _rref.__doc__
def _normalize_op_args(self, op, col, k, col1, col2, error_str="col"):
"""Validate the arguments for a row/column operation. ``error_str``
can be one of "row" or "col" depending on the arguments being parsed."""
if op not in ["n->kn", "n<->m", "n->n+km"]:
raise ValueError("Unknown {} operation '{}'. Valid col operations "
"are 'n->kn', 'n<->m', 'n->n+km'".format(error_str, op))
# define self_col according to error_str
self_cols = self.cols if error_str == 'col' else self.rows
# normalize and validate the arguments
if op == "n->kn":
col = col if col is not None else col1
if col is None or k is None:
raise ValueError("For a {0} operation 'n->kn' you must provide the "
"kwargs `{0}` and `k`".format(error_str))
if not 0 <= col < self_cols:
raise ValueError("This matrix does not have a {} '{}'".format(error_str, col))
elif op == "n<->m":
# we need two cols to swap. It does not matter
# how they were specified, so gather them together and
# remove `None`
cols = {col, k, col1, col2}.difference([None])
if len(cols) > 2:
# maybe the user left `k` by mistake?
cols = {col, col1, col2}.difference([None])
if len(cols) != 2:
raise ValueError("For a {0} operation 'n<->m' you must provide the "
"kwargs `{0}1` and `{0}2`".format(error_str))
col1, col2 = cols
if not 0 <= col1 < self_cols:
raise ValueError("This matrix does not have a {} '{}'".format(error_str, col1))
if not 0 <= col2 < self_cols:
raise ValueError("This matrix does not have a {} '{}'".format(error_str, col2))
elif op == "n->n+km":
col = col1 if col is None else col
col2 = col1 if col2 is None else col2
if col is None or col2 is None or k is None:
raise ValueError("For a {0} operation 'n->n+km' you must provide the "
"kwargs `{0}`, `k`, and `{0}2`".format(error_str))
if col == col2:
raise ValueError("For a {0} operation 'n->n+km' `{0}` and `{0}2` must "
"be different.".format(error_str))
if not 0 <= col < self_cols:
raise ValueError("This matrix does not have a {} '{}'".format(error_str, col))
if not 0 <= col2 < self_cols:
raise ValueError("This matrix does not have a {} '{}'".format(error_str, col2))
else:
raise ValueError('invalid operation %s' % repr(op))
return op, col, k, col1, col2
def _eval_col_op_multiply_col_by_const(self, col, k):
def entry(i, j):
if j == col:
return k * self[i, j]
return self[i, j]
return self._new(self.rows, self.cols, entry)
def _eval_col_op_swap(self, col1, col2):
def entry(i, j):
if j == col1:
return self[i, col2]
elif j == col2:
return self[i, col1]
return self[i, j]
return self._new(self.rows, self.cols, entry)
def _eval_col_op_add_multiple_to_other_col(self, col, k, col2):
def entry(i, j):
if j == col:
return self[i, j] + k * self[i, col2]
return self[i, j]
return self._new(self.rows, self.cols, entry)
def _eval_row_op_swap(self, row1, row2):
def entry(i, j):
if i == row1:
return self[row2, j]
elif i == row2:
return self[row1, j]
return self[i, j]
return self._new(self.rows, self.cols, entry)
def _eval_row_op_multiply_row_by_const(self, row, k):
def entry(i, j):
if i == row:
return k * self[i, j]
return self[i, j]
return self._new(self.rows, self.cols, entry)
def _eval_row_op_add_multiple_to_other_row(self, row, k, row2):
def entry(i, j):
if i == row:
return self[i, j] + k * self[row2, j]
return self[i, j]
return self._new(self.rows, self.cols, entry)
def elementary_col_op(self, op="n->kn", col=None, k=None, col1=None, col2=None):
"""Performs the elementary column operation `op`.
`op` may be one of
* ``"n->kn"`` (column n goes to k*n)
* ``"n<->m"`` (swap column n and column m)
* ``"n->n+km"`` (column n goes to column n + k*column m)
Parameters
==========
op : string; the elementary row operation
col : the column to apply the column operation
k : the multiple to apply in the column operation
col1 : one column of a column swap
col2 : second column of a column swap or column "m" in the column operation
"n->n+km"
"""
op, col, k, col1, col2 = self._normalize_op_args(op, col, k, col1, col2, "col")
# now that we've validated, we're all good to dispatch
if op == "n->kn":
return self._eval_col_op_multiply_col_by_const(col, k)
if op == "n<->m":
return self._eval_col_op_swap(col1, col2)
if op == "n->n+km":
return self._eval_col_op_add_multiple_to_other_col(col, k, col2)
def elementary_row_op(self, op="n->kn", row=None, k=None, row1=None, row2=None):
"""Performs the elementary row operation `op`.
`op` may be one of
* ``"n->kn"`` (row n goes to k*n)
* ``"n<->m"`` (swap row n and row m)
* ``"n->n+km"`` (row n goes to row n + k*row m)
Parameters
==========
op : string; the elementary row operation
row : the row to apply the row operation
k : the multiple to apply in the row operation
row1 : one row of a row swap
row2 : second row of a row swap or row "m" in the row operation
"n->n+km"
"""
op, row, k, row1, row2 = self._normalize_op_args(op, row, k, row1, row2, "row")
# now that we've validated, we're all good to dispatch
if op == "n->kn":
return self._eval_row_op_multiply_row_by_const(row, k)
if op == "n<->m":
return self._eval_row_op_swap(row1, row2)
if op == "n->n+km":
return self._eval_row_op_add_multiple_to_other_row(row, k, row2)
class MatrixSubspaces(MatrixReductions):
"""Provides methods relating to the fundamental subspaces of a matrix.
Should not be instantiated directly. See ``subspaces.py`` for their
implementations."""
def columnspace(self, simplify=False):
return _columnspace(self, simplify=simplify)
def nullspace(self, simplify=False, iszerofunc=_iszero):
return _nullspace(self, simplify=simplify, iszerofunc=iszerofunc)
def rowspace(self, simplify=False):
return _rowspace(self, simplify=simplify)
# This is a classmethod but is converted to such later in order to allow
# assignment of __doc__ since that does not work for already wrapped
# classmethods in Python 3.6.
def orthogonalize(cls, *vecs, **kwargs):
return _orthogonalize(cls, *vecs, **kwargs)
columnspace.__doc__ = _columnspace.__doc__
nullspace.__doc__ = _nullspace.__doc__
rowspace.__doc__ = _rowspace.__doc__
orthogonalize.__doc__ = _orthogonalize.__doc__
orthogonalize = classmethod(orthogonalize) # type:ignore
class MatrixEigen(MatrixSubspaces):
"""Provides basic matrix eigenvalue/vector operations.
Should not be instantiated directly. See ``eigen.py`` for their
implementations."""
def eigenvals(self, error_when_incomplete=True, **flags):
return _eigenvals(self, error_when_incomplete=error_when_incomplete, **flags)
def eigenvects(self, error_when_incomplete=True, iszerofunc=_iszero, **flags):
return _eigenvects(self, error_when_incomplete=error_when_incomplete,
iszerofunc=iszerofunc, **flags)
def is_diagonalizable(self, reals_only=False, **kwargs):
return _is_diagonalizable(self, reals_only=reals_only, **kwargs)
def diagonalize(self, reals_only=False, sort=False, normalize=False):
return _diagonalize(self, reals_only=reals_only, sort=sort,
normalize=normalize)
def bidiagonalize(self, upper=True):
return _bidiagonalize(self, upper=upper)
def bidiagonal_decomposition(self, upper=True):
return _bidiagonal_decomposition(self, upper=upper)
@property
def is_positive_definite(self):
return _is_positive_definite(self)
@property
def is_positive_semidefinite(self):
return _is_positive_semidefinite(self)
@property
def is_negative_definite(self):
return _is_negative_definite(self)
@property
def is_negative_semidefinite(self):
return _is_negative_semidefinite(self)
@property
def is_indefinite(self):
return _is_indefinite(self)
def jordan_form(self, calc_transform=True, **kwargs):
return _jordan_form(self, calc_transform=calc_transform, **kwargs)
def left_eigenvects(self, **flags):
return _left_eigenvects(self, **flags)
def singular_values(self):
return _singular_values(self)
eigenvals.__doc__ = _eigenvals.__doc__
eigenvects.__doc__ = _eigenvects.__doc__
is_diagonalizable.__doc__ = _is_diagonalizable.__doc__
diagonalize.__doc__ = _diagonalize.__doc__
is_positive_definite.__doc__ = _is_positive_definite.__doc__
is_positive_semidefinite.__doc__ = _is_positive_semidefinite.__doc__
is_negative_definite.__doc__ = _is_negative_definite.__doc__
is_negative_semidefinite.__doc__ = _is_negative_semidefinite.__doc__
is_indefinite.__doc__ = _is_indefinite.__doc__
jordan_form.__doc__ = _jordan_form.__doc__
left_eigenvects.__doc__ = _left_eigenvects.__doc__
singular_values.__doc__ = _singular_values.__doc__
bidiagonalize.__doc__ = _bidiagonalize.__doc__
bidiagonal_decomposition.__doc__ = _bidiagonal_decomposition.__doc__
class MatrixCalculus(MatrixCommon):
"""Provides calculus-related matrix operations."""
def diff(self, *args, evaluate=True, **kwargs):
"""Calculate the derivative of each element in the matrix.
Examples
========
>>> from sympy import Matrix
>>> from sympy.abc import x, y
>>> M = Matrix([[x, y], [1, 0]])
>>> M.diff(x)
Matrix([
[1, 0],
[0, 0]])
See Also
========
integrate
limit
"""
# XXX this should be handled here rather than in Derivative
from sympy.tensor.array.array_derivatives import ArrayDerivative
deriv = ArrayDerivative(self, *args, evaluate=evaluate)
# XXX This can rather changed to always return immutable matrix
if not isinstance(self, Basic) and evaluate:
return deriv.as_mutable()
return deriv
def _eval_derivative(self, arg):
return self.applyfunc(lambda x: x.diff(arg))
def integrate(self, *args, **kwargs):
"""Integrate each element of the matrix. ``args`` will
be passed to the ``integrate`` function.
Examples
========
>>> from sympy import Matrix
>>> from sympy.abc import x, y
>>> M = Matrix([[x, y], [1, 0]])
>>> M.integrate((x, ))
Matrix([
[x**2/2, x*y],
[ x, 0]])
>>> M.integrate((x, 0, 2))
Matrix([
[2, 2*y],
[2, 0]])
See Also
========
limit
diff
"""
return self.applyfunc(lambda x: x.integrate(*args, **kwargs))
def jacobian(self, X):
"""Calculates the Jacobian matrix (derivative of a vector-valued function).
Parameters
==========
``self`` : vector of expressions representing functions f_i(x_1, ..., x_n).
X : set of x_i's in order, it can be a list or a Matrix
Both ``self`` and X can be a row or a column matrix in any order
(i.e., jacobian() should always work).
Examples
========
>>> from sympy import sin, cos, Matrix
>>> from sympy.abc import rho, phi
>>> X = Matrix([rho*cos(phi), rho*sin(phi), rho**2])
>>> Y = Matrix([rho, phi])
>>> X.jacobian(Y)
Matrix([
[cos(phi), -rho*sin(phi)],
[sin(phi), rho*cos(phi)],
[ 2*rho, 0]])
>>> X = Matrix([rho*cos(phi), rho*sin(phi)])
>>> X.jacobian(Y)
Matrix([
[cos(phi), -rho*sin(phi)],
[sin(phi), rho*cos(phi)]])
See Also
========
hessian
wronskian
"""
if not isinstance(X, MatrixBase):
X = self._new(X)
# Both X and ``self`` can be a row or a column matrix, so we need to make
# sure all valid combinations work, but everything else fails:
if self.shape[0] == 1:
m = self.shape[1]
elif self.shape[1] == 1:
m = self.shape[0]
else:
raise TypeError("``self`` must be a row or a column matrix")
if X.shape[0] == 1:
n = X.shape[1]
elif X.shape[1] == 1:
n = X.shape[0]
else:
raise TypeError("X must be a row or a column matrix")
# m is the number of functions and n is the number of variables
# computing the Jacobian is now easy:
return self._new(m, n, lambda j, i: self[j].diff(X[i]))
def limit(self, *args):
"""Calculate the limit of each element in the matrix.
``args`` will be passed to the ``limit`` function.
Examples
========
>>> from sympy import Matrix
>>> from sympy.abc import x, y
>>> M = Matrix([[x, y], [1, 0]])
>>> M.limit(x, 2)
Matrix([
[2, y],
[1, 0]])
See Also
========
integrate
diff
"""
return self.applyfunc(lambda x: x.limit(*args))
# https://github.com/sympy/sympy/pull/12854
class MatrixDeprecated(MatrixCommon):
"""A class to house deprecated matrix methods."""
def berkowitz_charpoly(self, x=Dummy('lambda'), simplify=_simplify):
return self.charpoly(x=x)
def berkowitz_det(self):
"""Computes determinant using Berkowitz method.
See Also
========
det
berkowitz
"""
return self.det(method='berkowitz')
def berkowitz_eigenvals(self, **flags):
"""Computes eigenvalues of a Matrix using Berkowitz method.
See Also
========
berkowitz
"""
return self.eigenvals(**flags)
def berkowitz_minors(self):
"""Computes principal minors using Berkowitz method.
See Also
========
berkowitz
"""
sign, minors = self.one, []
for poly in self.berkowitz():
minors.append(sign * poly[-1])
sign = -sign
return tuple(minors)
def berkowitz(self):
from sympy.matrices import zeros
berk = ((1,),)
if not self:
return berk
if not self.is_square:
raise NonSquareMatrixError()
A, N = self, self.rows
transforms = [0] * (N - 1)
for n in range(N, 1, -1):
T, k = zeros(n + 1, n), n - 1
R, C = -A[k, :k], A[:k, k]
A, a = A[:k, :k], -A[k, k]
items = [C]
for i in range(0, n - 2):
items.append(A * items[i])
for i, B in enumerate(items):
items[i] = (R * B)[0, 0]
items = [self.one, a] + items
for i in range(n):
T[i:, i] = items[:n - i + 1]
transforms[k - 1] = T
polys = [self._new([self.one, -A[0, 0]])]
for i, T in enumerate(transforms):
polys.append(T * polys[i])
return berk + tuple(map(tuple, polys))
def cofactorMatrix(self, method="berkowitz"):
return self.cofactor_matrix(method=method)
def det_bareis(self):
return _det_bareiss(self)
def det_LU_decomposition(self):
"""Compute matrix determinant using LU decomposition.
Note that this method fails if the LU decomposition itself
fails. In particular, if the matrix has no inverse this method
will fail.
TODO: Implement algorithm for sparse matrices (SFF),
https://www.eecis.udel.edu/~saunders/papers/sffge/it5.ps
See Also
========
det
det_bareiss
berkowitz_det
"""
return self.det(method='lu')
def jordan_cell(self, eigenval, n):
return self.jordan_block(size=n, eigenvalue=eigenval)
def jordan_cells(self, calc_transformation=True):
P, J = self.jordan_form()
return P, J.get_diag_blocks()
def minorEntry(self, i, j, method="berkowitz"):
return self.minor(i, j, method=method)
def minorMatrix(self, i, j):
return self.minor_submatrix(i, j)
def permuteBkwd(self, perm):
"""Permute the rows of the matrix with the given permutation in reverse."""
return self.permute_rows(perm, direction='backward')
def permuteFwd(self, perm):
"""Permute the rows of the matrix with the given permutation."""
return self.permute_rows(perm, direction='forward')
PK ]ZZZ�P��Є Є sympy/matrices/matrixbase.pyfrom collections import defaultdict
from collections.abc import Iterable
from inspect import isfunction
from functools import reduce
from sympy.assumptions.refine import refine
from sympy.core import SympifyError, Add
from sympy.core.basic import Atom, Basic
from sympy.core.kind import UndefinedKind
from sympy.core.numbers import Integer
from sympy.core.mod import Mod
from sympy.core.symbol import Symbol, Dummy
from sympy.core.sympify import sympify, _sympify
from sympy.core.function import diff
from sympy.polys import cancel
from sympy.functions.elementary.complexes import Abs, re, im
from sympy.printing import sstr
from sympy.functions.elementary.miscellaneous import Max, Min, sqrt
from sympy.functions.special.tensor_functions import KroneckerDelta, LeviCivita
from sympy.core.singleton import S
from sympy.printing.defaults import Printable
from sympy.printing.str import StrPrinter
from sympy.functions.elementary.exponential import exp, log
from sympy.functions.combinatorial.factorials import binomial, factorial
import mpmath as mp
from collections.abc import Callable
from sympy.utilities.iterables import reshape
from sympy.core.expr import Expr
from sympy.core.power import Pow
from sympy.core.symbol import uniquely_named_symbol
from .utilities import _dotprodsimp, _simplify as _utilities_simplify
from sympy.polys.polytools import Poly
from sympy.utilities.iterables import flatten, is_sequence
from sympy.utilities.misc import as_int, filldedent
from sympy.core.decorators import call_highest_priority
from sympy.core.logic import fuzzy_and, FuzzyBool
from sympy.tensor.array import NDimArray
from sympy.utilities.iterables import NotIterable
from .utilities import _get_intermediate_simp_bool
from .kind import MatrixKind
from .exceptions import (
MatrixError, ShapeError, NonSquareMatrixError, NonInvertibleMatrixError,
)
from .utilities import _iszero, _is_zero_after_expand_mul
from .determinant import (
_find_reasonable_pivot, _find_reasonable_pivot_naive,
_adjugate, _charpoly, _cofactor, _cofactor_matrix, _per,
_det, _det_bareiss, _det_berkowitz, _det_bird, _det_laplace, _det_LU,
_minor, _minor_submatrix)
from .reductions import _is_echelon, _echelon_form, _rank, _rref
from .solvers import (
_diagonal_solve, _lower_triangular_solve, _upper_triangular_solve,
_cholesky_solve, _LDLsolve, _LUsolve, _QRsolve, _gauss_jordan_solve,
_pinv_solve, _cramer_solve, _solve, _solve_least_squares)
from .inverse import (
_pinv, _inv_ADJ, _inv_GE, _inv_LU, _inv_CH, _inv_LDL, _inv_QR,
_inv, _inv_block)
from .subspaces import _columnspace, _nullspace, _rowspace, _orthogonalize
from .eigen import (
_eigenvals, _eigenvects,
_bidiagonalize, _bidiagonal_decomposition,
_is_diagonalizable, _diagonalize,
_is_positive_definite, _is_positive_semidefinite,
_is_negative_definite, _is_negative_semidefinite, _is_indefinite,
_jordan_form, _left_eigenvects, _singular_values)
from .decompositions import (
_rank_decomposition, _cholesky, _LDLdecomposition,
_LUdecomposition, _LUdecomposition_Simple, _LUdecompositionFF,
_singular_value_decomposition, _QRdecomposition, _upper_hessenberg_decomposition)
from .graph import (
_connected_components, _connected_components_decomposition,
_strongly_connected_components, _strongly_connected_components_decomposition)
__doctest_requires__ = {
('MatrixBase.is_indefinite',
'MatrixBase.is_positive_definite',
'MatrixBase.is_positive_semidefinite',
'MatrixBase.is_negative_definite',
'MatrixBase.is_negative_semidefinite'): ['matplotlib'],
}
class MatrixBase(Printable):
"""All common matrix operations including basic arithmetic, shaping,
and special matrices like `zeros`, and `eye`."""
_op_priority = 10.01
# Added just for numpy compatibility
__array_priority__ = 11
is_Matrix = True
_class_priority = 3
_sympify = staticmethod(sympify)
zero = S.Zero
one = S.One
_diff_wrt = True # type: bool
rows = None # type: int
cols = None # type: int
_simplify = None
@classmethod
def _new(cls, *args, **kwargs):
"""`_new` must, at minimum, be callable as
`_new(rows, cols, mat) where mat is a flat list of the
elements of the matrix."""
raise NotImplementedError("Subclasses must implement this.")
def __eq__(self, other):
raise NotImplementedError("Subclasses must implement this.")
def __getitem__(self, key):
"""Implementations of __getitem__ should accept ints, in which
case the matrix is indexed as a flat list, tuples (i,j) in which
case the (i,j) entry is returned, slices, or mixed tuples (a,b)
where a and b are any combination of slices and integers."""
raise NotImplementedError("Subclasses must implement this.")
@property
def shape(self):
"""The shape (dimensions) of the matrix as the 2-tuple (rows, cols).
Examples
========
>>> from sympy import zeros
>>> M = zeros(2, 3)
>>> M.shape
(2, 3)
>>> M.rows
2
>>> M.cols
3
"""
return (self.rows, self.cols)
def _eval_col_del(self, col):
def entry(i, j):
return self[i, j] if j < col else self[i, j + 1]
return self._new(self.rows, self.cols - 1, entry)
def _eval_col_insert(self, pos, other):
def entry(i, j):
if j < pos:
return self[i, j]
elif pos <= j < pos + other.cols:
return other[i, j - pos]
return self[i, j - other.cols]
return self._new(self.rows, self.cols + other.cols, entry)
def _eval_col_join(self, other):
rows = self.rows
def entry(i, j):
if i < rows:
return self[i, j]
return other[i - rows, j]
return classof(self, other)._new(self.rows + other.rows, self.cols,
entry)
def _eval_extract(self, rowsList, colsList):
mat = list(self)
cols = self.cols
indices = (i * cols + j for i in rowsList for j in colsList)
return self._new(len(rowsList), len(colsList),
[mat[i] for i in indices])
def _eval_get_diag_blocks(self):
sub_blocks = []
def recurse_sub_blocks(M):
i = 1
while i <= M.shape[0]:
if i == 1:
to_the_right = M[0, i:]
to_the_bottom = M[i:, 0]
else:
to_the_right = M[:i, i:]
to_the_bottom = M[i:, :i]
if any(to_the_right) or any(to_the_bottom):
i += 1
continue
else:
sub_blocks.append(M[:i, :i])
if M.shape == M[:i, :i].shape:
return
else:
recurse_sub_blocks(M[i:, i:])
return
recurse_sub_blocks(self)
return sub_blocks
def _eval_row_del(self, row):
def entry(i, j):
return self[i, j] if i < row else self[i + 1, j]
return self._new(self.rows - 1, self.cols, entry)
def _eval_row_insert(self, pos, other):
entries = list(self)
insert_pos = pos * self.cols
entries[insert_pos:insert_pos] = list(other)
return self._new(self.rows + other.rows, self.cols, entries)
def _eval_row_join(self, other):
cols = self.cols
def entry(i, j):
if j < cols:
return self[i, j]
return other[i, j - cols]
return classof(self, other)._new(self.rows, self.cols + other.cols,
entry)
def _eval_tolist(self):
return [list(self[i,:]) for i in range(self.rows)]
def _eval_todok(self):
dok = {}
rows, cols = self.shape
for i in range(rows):
for j in range(cols):
val = self[i, j]
if val != self.zero:
dok[i, j] = val
return dok
@classmethod
def _eval_from_dok(cls, rows, cols, dok):
out_flat = [cls.zero] * (rows * cols)
for (i, j), val in dok.items():
out_flat[i * cols + j] = val
return cls._new(rows, cols, out_flat)
def _eval_vec(self):
rows = self.rows
def entry(n, _):
# we want to read off the columns first
j = n // rows
i = n - j * rows
return self[i, j]
return self._new(len(self), 1, entry)
def _eval_vech(self, diagonal):
c = self.cols
v = []
if diagonal:
for j in range(c):
for i in range(j, c):
v.append(self[i, j])
else:
for j in range(c):
for i in range(j + 1, c):
v.append(self[i, j])
return self._new(len(v), 1, v)
def col_del(self, col):
"""Delete the specified column."""
if col < 0:
col += self.cols
if not 0 <= col < self.cols:
raise IndexError("Column {} is out of range.".format(col))
return self._eval_col_del(col)
def col_insert(self, pos, other):
"""Insert one or more columns at the given column position.
Examples
========
>>> from sympy import zeros, ones
>>> M = zeros(3)
>>> V = ones(3, 1)
>>> M.col_insert(1, V)
Matrix([
[0, 1, 0, 0],
[0, 1, 0, 0],
[0, 1, 0, 0]])
See Also
========
col
row_insert
"""
# Allows you to build a matrix even if it is null matrix
if not self:
return type(self)(other)
pos = as_int(pos)
if pos < 0:
pos = self.cols + pos
if pos < 0:
pos = 0
elif pos > self.cols:
pos = self.cols
if self.rows != other.rows:
raise ShapeError(
"The matrices have incompatible number of rows ({} and {})"
.format(self.rows, other.rows))
return self._eval_col_insert(pos, other)
def col_join(self, other):
"""Concatenates two matrices along self's last and other's first row.
Examples
========
>>> from sympy import zeros, ones
>>> M = zeros(3)
>>> V = ones(1, 3)
>>> M.col_join(V)
Matrix([
[0, 0, 0],
[0, 0, 0],
[0, 0, 0],
[1, 1, 1]])
See Also
========
col
row_join
"""
# A null matrix can always be stacked (see #10770)
if self.rows == 0 and self.cols != other.cols:
return self._new(0, other.cols, []).col_join(other)
if self.cols != other.cols:
raise ShapeError(
"The matrices have incompatible number of columns ({} and {})"
.format(self.cols, other.cols))
return self._eval_col_join(other)
def col(self, j):
"""Elementary column selector.
Examples
========
>>> from sympy import eye
>>> eye(2).col(0)
Matrix([
[1],
[0]])
See Also
========
row
col_del
col_join
col_insert
"""
return self[:, j]
def extract(self, rowsList, colsList):
r"""Return a submatrix by specifying a list of rows and columns.
Negative indices can be given. All indices must be in the range
$-n \le i < n$ where $n$ is the number of rows or columns.
Examples
========
>>> from sympy import Matrix
>>> m = Matrix(4, 3, range(12))
>>> m
Matrix([
[0, 1, 2],
[3, 4, 5],
[6, 7, 8],
[9, 10, 11]])
>>> m.extract([0, 1, 3], [0, 1])
Matrix([
[0, 1],
[3, 4],
[9, 10]])
Rows or columns can be repeated:
>>> m.extract([0, 0, 1], [-1])
Matrix([
[2],
[2],
[5]])
Every other row can be taken by using range to provide the indices:
>>> m.extract(range(0, m.rows, 2), [-1])
Matrix([
[2],
[8]])
RowsList or colsList can also be a list of booleans, in which case
the rows or columns corresponding to the True values will be selected:
>>> m.extract([0, 1, 2, 3], [True, False, True])
Matrix([
[0, 2],
[3, 5],
[6, 8],
[9, 11]])
"""
if not is_sequence(rowsList) or not is_sequence(colsList):
raise TypeError("rowsList and colsList must be iterable")
# ensure rowsList and colsList are lists of integers
if rowsList and all(isinstance(i, bool) for i in rowsList):
rowsList = [index for index, item in enumerate(rowsList) if item]
if colsList and all(isinstance(i, bool) for i in colsList):
colsList = [index for index, item in enumerate(colsList) if item]
# ensure everything is in range
rowsList = [a2idx(k, self.rows) for k in rowsList]
colsList = [a2idx(k, self.cols) for k in colsList]
return self._eval_extract(rowsList, colsList)
def get_diag_blocks(self):
"""Obtains the square sub-matrices on the main diagonal of a square matrix.
Useful for inverting symbolic matrices or solving systems of
linear equations which may be decoupled by having a block diagonal
structure.
Examples
========
>>> from sympy import Matrix
>>> from sympy.abc import x, y, z
>>> A = Matrix([[1, 3, 0, 0], [y, z*z, 0, 0], [0, 0, x, 0], [0, 0, 0, 0]])
>>> a1, a2, a3 = A.get_diag_blocks()
>>> a1
Matrix([
[1, 3],
[y, z**2]])
>>> a2
Matrix([[x]])
>>> a3
Matrix([[0]])
"""
return self._eval_get_diag_blocks()
@classmethod
def hstack(cls, *args):
"""Return a matrix formed by joining args horizontally (i.e.
by repeated application of row_join).
Examples
========
>>> from sympy import Matrix, eye
>>> Matrix.hstack(eye(2), 2*eye(2))
Matrix([
[1, 0, 2, 0],
[0, 1, 0, 2]])
"""
if len(args) == 0:
return cls._new()
kls = type(args[0])
return reduce(kls.row_join, args)
def reshape(self, rows, cols):
"""Reshape the matrix. Total number of elements must remain the same.
Examples
========
>>> from sympy import Matrix
>>> m = Matrix(2, 3, lambda i, j: 1)
>>> m
Matrix([
[1, 1, 1],
[1, 1, 1]])
>>> m.reshape(1, 6)
Matrix([[1, 1, 1, 1, 1, 1]])
>>> m.reshape(3, 2)
Matrix([
[1, 1],
[1, 1],
[1, 1]])
"""
if self.rows * self.cols != rows * cols:
raise ValueError("Invalid reshape parameters %d %d" % (rows, cols))
return self._new(rows, cols, lambda i, j: self[i * cols + j])
def row_del(self, row):
"""Delete the specified row."""
if row < 0:
row += self.rows
if not 0 <= row < self.rows:
raise IndexError("Row {} is out of range.".format(row))
return self._eval_row_del(row)
def row_insert(self, pos, other):
"""Insert one or more rows at the given row position.
Examples
========
>>> from sympy import zeros, ones
>>> M = zeros(3)
>>> V = ones(1, 3)
>>> M.row_insert(1, V)
Matrix([
[0, 0, 0],
[1, 1, 1],
[0, 0, 0],
[0, 0, 0]])
See Also
========
row
col_insert
"""
# Allows you to build a matrix even if it is null matrix
if not self:
return self._new(other)
pos = as_int(pos)
if pos < 0:
pos = self.rows + pos
if pos < 0:
pos = 0
elif pos > self.rows:
pos = self.rows
if self.cols != other.cols:
raise ShapeError(
"The matrices have incompatible number of columns ({} and {})"
.format(self.cols, other.cols))
return self._eval_row_insert(pos, other)
def row_join(self, other):
"""Concatenates two matrices along self's last and rhs's first column
Examples
========
>>> from sympy import zeros, ones
>>> M = zeros(3)
>>> V = ones(3, 1)
>>> M.row_join(V)
Matrix([
[0, 0, 0, 1],
[0, 0, 0, 1],
[0, 0, 0, 1]])
See Also
========
row
col_join
"""
# A null matrix can always be stacked (see #10770)
if self.cols == 0 and self.rows != other.rows:
return self._new(other.rows, 0, []).row_join(other)
if self.rows != other.rows:
raise ShapeError(
"The matrices have incompatible number of rows ({} and {})"
.format(self.rows, other.rows))
return self._eval_row_join(other)
def diagonal(self, k=0):
"""Returns the kth diagonal of self. The main diagonal
corresponds to `k=0`; diagonals above and below correspond to
`k > 0` and `k < 0`, respectively. The values of `self[i, j]`
for which `j - i = k`, are returned in order of increasing
`i + j`, starting with `i + j = |k|`.
Examples
========
>>> from sympy import Matrix
>>> m = Matrix(3, 3, lambda i, j: j - i); m
Matrix([
[ 0, 1, 2],
[-1, 0, 1],
[-2, -1, 0]])
>>> _.diagonal()
Matrix([[0, 0, 0]])
>>> m.diagonal(1)
Matrix([[1, 1]])
>>> m.diagonal(-2)
Matrix([[-2]])
Even though the diagonal is returned as a Matrix, the element
retrieval can be done with a single index:
>>> Matrix.diag(1, 2, 3).diagonal()[1] # instead of [0, 1]
2
See Also
========
diag
"""
rv = []
k = as_int(k)
r = 0 if k > 0 else -k
c = 0 if r else k
while True:
if r == self.rows or c == self.cols:
break
rv.append(self[r, c])
r += 1
c += 1
if not rv:
raise ValueError(filldedent('''
The %s diagonal is out of range [%s, %s]''' % (
k, 1 - self.rows, self.cols - 1)))
return self._new(1, len(rv), rv)
def row(self, i):
"""Elementary row selector.
Examples
========
>>> from sympy import eye
>>> eye(2).row(0)
Matrix([[1, 0]])
See Also
========
col
row_del
row_join
row_insert
"""
return self[i, :]
def todok(self):
"""Return the matrix as dictionary of keys.
Examples
========
>>> from sympy import Matrix
>>> M = Matrix.eye(3)
>>> M.todok()
{(0, 0): 1, (1, 1): 1, (2, 2): 1}
"""
return self._eval_todok()
@classmethod
def from_dok(cls, rows, cols, dok):
"""Create a matrix from a dictionary of keys.
Examples
========
>>> from sympy import Matrix
>>> d = {(0, 0): 1, (1, 2): 3, (2, 1): 4}
>>> Matrix.from_dok(3, 3, d)
Matrix([
[1, 0, 0],
[0, 0, 3],
[0, 4, 0]])
"""
dok = {ij: cls._sympify(val) for ij, val in dok.items()}
return cls._eval_from_dok(rows, cols, dok)
def tolist(self):
"""Return the Matrix as a nested Python list.
Examples
========
>>> from sympy import Matrix, ones
>>> m = Matrix(3, 3, range(9))
>>> m
Matrix([
[0, 1, 2],
[3, 4, 5],
[6, 7, 8]])
>>> m.tolist()
[[0, 1, 2], [3, 4, 5], [6, 7, 8]]
>>> ones(3, 0).tolist()
[[], [], []]
When there are no rows then it will not be possible to tell how
many columns were in the original matrix:
>>> ones(0, 3).tolist()
[]
"""
if not self.rows:
return []
if not self.cols:
return [[] for i in range(self.rows)]
return self._eval_tolist()
def todod(M):
"""Returns matrix as dict of dicts containing non-zero elements of the Matrix
Examples
========
>>> from sympy import Matrix
>>> A = Matrix([[0, 1],[0, 3]])
>>> A
Matrix([
[0, 1],
[0, 3]])
>>> A.todod()
{0: {1: 1}, 1: {1: 3}}
"""
rowsdict = {}
Mlol = M.tolist()
for i, Mi in enumerate(Mlol):
row = {j: Mij for j, Mij in enumerate(Mi) if Mij}
if row:
rowsdict[i] = row
return rowsdict
def vec(self):
"""Return the Matrix converted into a one column matrix by stacking columns
Examples
========
>>> from sympy import Matrix
>>> m=Matrix([[1, 3], [2, 4]])
>>> m
Matrix([
[1, 3],
[2, 4]])
>>> m.vec()
Matrix([
[1],
[2],
[3],
[4]])
See Also
========
vech
"""
return self._eval_vec()
def vech(self, diagonal=True, check_symmetry=True):
"""Reshapes the matrix into a column vector by stacking the
elements in the lower triangle.
Parameters
==========
diagonal : bool, optional
If ``True``, it includes the diagonal elements.
check_symmetry : bool, optional
If ``True``, it checks whether the matrix is symmetric.
Examples
========
>>> from sympy import Matrix
>>> m=Matrix([[1, 2], [2, 3]])
>>> m
Matrix([
[1, 2],
[2, 3]])
>>> m.vech()
Matrix([
[1],
[2],
[3]])
>>> m.vech(diagonal=False)
Matrix([[2]])
Notes
=====
This should work for symmetric matrices and ``vech`` can
represent symmetric matrices in vector form with less size than
``vec``.
See Also
========
vec
"""
if not self.is_square:
raise NonSquareMatrixError
if check_symmetry and not self.is_symmetric():
raise ValueError("The matrix is not symmetric.")
return self._eval_vech(diagonal)
@classmethod
def vstack(cls, *args):
"""Return a matrix formed by joining args vertically (i.e.
by repeated application of col_join).
Examples
========
>>> from sympy import Matrix, eye
>>> Matrix.vstack(eye(2), 2*eye(2))
Matrix([
[1, 0],
[0, 1],
[2, 0],
[0, 2]])
"""
if len(args) == 0:
return cls._new()
kls = type(args[0])
return reduce(kls.col_join, args)
@classmethod
def _eval_diag(cls, rows, cols, diag_dict):
"""diag_dict is a defaultdict containing
all the entries of the diagonal matrix."""
def entry(i, j):
return diag_dict[(i, j)]
return cls._new(rows, cols, entry)
@classmethod
def _eval_eye(cls, rows, cols):
vals = [cls.zero]*(rows*cols)
vals[::cols+1] = [cls.one]*min(rows, cols)
return cls._new(rows, cols, vals, copy=False)
@classmethod
def _eval_jordan_block(cls, size: int, eigenvalue, band='upper'):
if band == 'lower':
def entry(i, j):
if i == j:
return eigenvalue
elif j + 1 == i:
return cls.one
return cls.zero
else:
def entry(i, j):
if i == j:
return eigenvalue
elif i + 1 == j:
return cls.one
return cls.zero
return cls._new(size, size, entry)
@classmethod
def _eval_ones(cls, rows, cols):
def entry(i, j):
return cls.one
return cls._new(rows, cols, entry)
@classmethod
def _eval_zeros(cls, rows, cols):
return cls._new(rows, cols, [cls.zero]*(rows*cols), copy=False)
@classmethod
def _eval_wilkinson(cls, n):
def entry(i, j):
return cls.one if i + 1 == j else cls.zero
D = cls._new(2*n + 1, 2*n + 1, entry)
wminus = cls.diag(list(range(-n, n + 1)), unpack=True) + D + D.T
wplus = abs(cls.diag(list(range(-n, n + 1)), unpack=True)) + D + D.T
return wminus, wplus
@classmethod
def diag(kls, *args, strict=False, unpack=True, rows=None, cols=None, **kwargs):
"""Returns a matrix with the specified diagonal.
If matrices are passed, a block-diagonal matrix
is created (i.e. the "direct sum" of the matrices).
kwargs
======
rows : rows of the resulting matrix; computed if
not given.
cols : columns of the resulting matrix; computed if
not given.
cls : class for the resulting matrix
unpack : bool which, when True (default), unpacks a single
sequence rather than interpreting it as a Matrix.
strict : bool which, when False (default), allows Matrices to
have variable-length rows.
Examples
========
>>> from sympy import Matrix
>>> Matrix.diag(1, 2, 3)
Matrix([
[1, 0, 0],
[0, 2, 0],
[0, 0, 3]])
The current default is to unpack a single sequence. If this is
not desired, set `unpack=False` and it will be interpreted as
a matrix.
>>> Matrix.diag([1, 2, 3]) == Matrix.diag(1, 2, 3)
True
When more than one element is passed, each is interpreted as
something to put on the diagonal. Lists are converted to
matrices. Filling of the diagonal always continues from
the bottom right hand corner of the previous item: this
will create a block-diagonal matrix whether the matrices
are square or not.
>>> col = [1, 2, 3]
>>> row = [[4, 5]]
>>> Matrix.diag(col, row)
Matrix([
[1, 0, 0],
[2, 0, 0],
[3, 0, 0],
[0, 4, 5]])
When `unpack` is False, elements within a list need not all be
of the same length. Setting `strict` to True would raise a
ValueError for the following:
>>> Matrix.diag([[1, 2, 3], [4, 5], [6]], unpack=False)
Matrix([
[1, 2, 3],
[4, 5, 0],
[6, 0, 0]])
The type of the returned matrix can be set with the ``cls``
keyword.
>>> from sympy import ImmutableMatrix
>>> from sympy.utilities.misc import func_name
>>> func_name(Matrix.diag(1, cls=ImmutableMatrix))
'ImmutableDenseMatrix'
A zero dimension matrix can be used to position the start of
the filling at the start of an arbitrary row or column:
>>> from sympy import ones
>>> r2 = ones(0, 2)
>>> Matrix.diag(r2, 1, 2)
Matrix([
[0, 0, 1, 0],
[0, 0, 0, 2]])
See Also
========
eye
diagonal
.dense.diag
.expressions.blockmatrix.BlockMatrix
.sparsetools.banded
"""
from sympy.matrices.matrixbase import MatrixBase
from sympy.matrices.dense import Matrix
from sympy.matrices import SparseMatrix
klass = kwargs.get('cls', kls)
if unpack and len(args) == 1 and is_sequence(args[0]) and \
not isinstance(args[0], MatrixBase):
args = args[0]
# fill a default dict with the diagonal entries
diag_entries = defaultdict(int)
rmax = cmax = 0 # keep track of the biggest index seen
for m in args:
if isinstance(m, list):
if strict:
# if malformed, Matrix will raise an error
_ = Matrix(m)
r, c = _.shape
m = _.tolist()
else:
r, c, smat = SparseMatrix._handle_creation_inputs(m)
for (i, j), _ in smat.items():
diag_entries[(i + rmax, j + cmax)] = _
m = [] # to skip process below
elif hasattr(m, 'shape'): # a Matrix
# convert to list of lists
r, c = m.shape
m = m.tolist()
else: # in this case, we're a single value
diag_entries[(rmax, cmax)] = m
rmax += 1
cmax += 1
continue
# process list of lists
for i, mi in enumerate(m):
for j, _ in enumerate(mi):
diag_entries[(i + rmax, j + cmax)] = _
rmax += r
cmax += c
if rows is None:
rows, cols = cols, rows
if rows is None:
rows, cols = rmax, cmax
else:
cols = rows if cols is None else cols
if rows < rmax or cols < cmax:
raise ValueError(filldedent('''
The constructed matrix is {} x {} but a size of {} x {}
was specified.'''.format(rmax, cmax, rows, cols)))
return klass._eval_diag(rows, cols, diag_entries)
@classmethod
def eye(kls, rows, cols=None, **kwargs):
"""Returns an identity matrix.
Parameters
==========
rows : rows of the matrix
cols : cols of the matrix (if None, cols=rows)
kwargs
======
cls : class of the returned matrix
"""
if cols is None:
cols = rows
if rows < 0 or cols < 0:
raise ValueError("Cannot create a {} x {} matrix. "
"Both dimensions must be positive".format(rows, cols))
klass = kwargs.get('cls', kls)
rows, cols = as_int(rows), as_int(cols)
return klass._eval_eye(rows, cols)
@classmethod
def jordan_block(kls, size=None, eigenvalue=None, *, band='upper', **kwargs):
"""Returns a Jordan block
Parameters
==========
size : Integer, optional
Specifies the shape of the Jordan block matrix.
eigenvalue : Number or Symbol
Specifies the value for the main diagonal of the matrix.
.. note::
The keyword ``eigenval`` is also specified as an alias
of this keyword, but it is not recommended to use.
We may deprecate the alias in later release.
band : 'upper' or 'lower', optional
Specifies the position of the off-diagonal to put `1` s on.
cls : Matrix, optional
Specifies the matrix class of the output form.
If it is not specified, the class type where the method is
being executed on will be returned.
Returns
=======
Matrix
A Jordan block matrix.
Raises
======
ValueError
If insufficient arguments are given for matrix size
specification, or no eigenvalue is given.
Examples
========
Creating a default Jordan block:
>>> from sympy import Matrix
>>> from sympy.abc import x
>>> Matrix.jordan_block(4, x)
Matrix([
[x, 1, 0, 0],
[0, x, 1, 0],
[0, 0, x, 1],
[0, 0, 0, x]])
Creating an alternative Jordan block matrix where `1` is on
lower off-diagonal:
>>> Matrix.jordan_block(4, x, band='lower')
Matrix([
[x, 0, 0, 0],
[1, x, 0, 0],
[0, 1, x, 0],
[0, 0, 1, x]])
Creating a Jordan block with keyword arguments
>>> Matrix.jordan_block(size=4, eigenvalue=x)
Matrix([
[x, 1, 0, 0],
[0, x, 1, 0],
[0, 0, x, 1],
[0, 0, 0, x]])
References
==========
.. [1] https://en.wikipedia.org/wiki/Jordan_matrix
"""
klass = kwargs.pop('cls', kls)
eigenval = kwargs.get('eigenval', None)
if eigenvalue is None and eigenval is None:
raise ValueError("Must supply an eigenvalue")
elif eigenvalue != eigenval and None not in (eigenval, eigenvalue):
raise ValueError(
"Inconsistent values are given: 'eigenval'={}, "
"'eigenvalue'={}".format(eigenval, eigenvalue))
else:
if eigenval is not None:
eigenvalue = eigenval
if size is None:
raise ValueError("Must supply a matrix size")
size = as_int(size)
return klass._eval_jordan_block(size, eigenvalue, band)
@classmethod
def ones(kls, rows, cols=None, **kwargs):
"""Returns a matrix of ones.
Parameters
==========
rows : rows of the matrix
cols : cols of the matrix (if None, cols=rows)
kwargs
======
cls : class of the returned matrix
"""
if cols is None:
cols = rows
klass = kwargs.get('cls', kls)
rows, cols = as_int(rows), as_int(cols)
return klass._eval_ones(rows, cols)
@classmethod
def zeros(kls, rows, cols=None, **kwargs):
"""Returns a matrix of zeros.
Parameters
==========
rows : rows of the matrix
cols : cols of the matrix (if None, cols=rows)
kwargs
======
cls : class of the returned matrix
"""
if cols is None:
cols = rows
if rows < 0 or cols < 0:
raise ValueError("Cannot create a {} x {} matrix. "
"Both dimensions must be positive".format(rows, cols))
klass = kwargs.get('cls', kls)
rows, cols = as_int(rows), as_int(cols)
return klass._eval_zeros(rows, cols)
@classmethod
def companion(kls, poly):
"""Returns a companion matrix of a polynomial.
Examples
========
>>> from sympy import Matrix, Poly, Symbol, symbols
>>> x = Symbol('x')
>>> c0, c1, c2, c3, c4 = symbols('c0:5')
>>> p = Poly(c0 + c1*x + c2*x**2 + c3*x**3 + c4*x**4 + x**5, x)
>>> Matrix.companion(p)
Matrix([
[0, 0, 0, 0, -c0],
[1, 0, 0, 0, -c1],
[0, 1, 0, 0, -c2],
[0, 0, 1, 0, -c3],
[0, 0, 0, 1, -c4]])
"""
poly = kls._sympify(poly)
if not isinstance(poly, Poly):
raise ValueError("{} must be a Poly instance.".format(poly))
if not poly.is_monic:
raise ValueError("{} must be a monic polynomial.".format(poly))
if not poly.is_univariate:
raise ValueError(
"{} must be a univariate polynomial.".format(poly))
size = poly.degree()
if not size >= 1:
raise ValueError(
"{} must have degree not less than 1.".format(poly))
coeffs = poly.all_coeffs()
def entry(i, j):
if j == size - 1:
return -coeffs[-1 - i]
elif i == j + 1:
return kls.one
return kls.zero
return kls._new(size, size, entry)
@classmethod
def wilkinson(kls, n, **kwargs):
"""Returns two square Wilkinson Matrix of size 2*n + 1
$W_{2n + 1}^-, W_{2n + 1}^+ =$ Wilkinson(n)
Examples
========
>>> from sympy import Matrix
>>> wminus, wplus = Matrix.wilkinson(3)
>>> wminus
Matrix([
[-3, 1, 0, 0, 0, 0, 0],
[ 1, -2, 1, 0, 0, 0, 0],
[ 0, 1, -1, 1, 0, 0, 0],
[ 0, 0, 1, 0, 1, 0, 0],
[ 0, 0, 0, 1, 1, 1, 0],
[ 0, 0, 0, 0, 1, 2, 1],
[ 0, 0, 0, 0, 0, 1, 3]])
>>> wplus
Matrix([
[3, 1, 0, 0, 0, 0, 0],
[1, 2, 1, 0, 0, 0, 0],
[0, 1, 1, 1, 0, 0, 0],
[0, 0, 1, 0, 1, 0, 0],
[0, 0, 0, 1, 1, 1, 0],
[0, 0, 0, 0, 1, 2, 1],
[0, 0, 0, 0, 0, 1, 3]])
References
==========
.. [1] https://blogs.mathworks.com/cleve/2013/04/15/wilkinsons-matrices-2/
.. [2] J. H. Wilkinson, The Algebraic Eigenvalue Problem, Claredon Press, Oxford, 1965, 662 pp.
"""
klass = kwargs.get('cls', kls)
n = as_int(n)
return klass._eval_wilkinson(n)
# The RepMatrix subclass uses more efficient sparse implementations of
# _eval_iter_values and other things.
def _eval_iter_values(self):
return (i for i in self if i is not S.Zero)
def _eval_values(self):
return list(self.iter_values())
def _eval_iter_items(self):
for i in range(self.rows):
for j in range(self.cols):
if self[i, j]:
yield (i, j), self[i, j]
def _eval_atoms(self, *types):
values = self.values()
if len(values) < self.rows * self.cols and isinstance(S.Zero, types):
s = {S.Zero}
else:
s = set()
return s.union(*[v.atoms(*types) for v in values])
def _eval_free_symbols(self):
return set().union(*(i.free_symbols for i in set(self.values())))
def _eval_has(self, *patterns):
return any(a.has(*patterns) for a in self.iter_values())
def _eval_is_symbolic(self):
return self.has(Symbol)
# _eval_is_hermitian is called by some general SymPy
# routines and has a different *args signature. Make
# sure the names don't clash by adding `_matrix_` in name.
def _eval_is_matrix_hermitian(self, simpfunc):
herm = lambda i, j: simpfunc(self[i, j] - self[j, i].conjugate()).is_zero
return fuzzy_and(herm(i, j) for (i, j), v in self.iter_items())
def _eval_is_zero_matrix(self):
return fuzzy_and(v.is_zero for v in self.iter_values())
def _eval_is_Identity(self) -> FuzzyBool:
one = self.one
zero = self.zero
ident = lambda i, j, v: v is one if i == j else v is zero
return all(ident(i, j, v) for (i, j), v in self.iter_items())
def _eval_is_diagonal(self):
return fuzzy_and(v.is_zero for (i, j), v in self.iter_items() if i != j)
def _eval_is_lower(self):
return all(v.is_zero for (i, j), v in self.iter_items() if i < j)
def _eval_is_upper(self):
return all(v.is_zero for (i, j), v in self.iter_items() if i > j)
def _eval_is_lower_hessenberg(self):
return all(v.is_zero for (i, j), v in self.iter_items() if i + 1 < j)
def _eval_is_upper_hessenberg(self):
return all(v.is_zero for (i, j), v in self.iter_items() if i > j + 1)
def _eval_is_symmetric(self, simpfunc):
sym = lambda i, j: simpfunc(self[i, j] - self[j, i]).is_zero
return fuzzy_and(sym(i, j) for (i, j), v in self.iter_items())
def _eval_is_anti_symmetric(self, simpfunc):
anti = lambda i, j: simpfunc(self[i, j] + self[j, i]).is_zero
return fuzzy_and(anti(i, j) for (i, j), v in self.iter_items())
def _has_positive_diagonals(self):
diagonal_entries = (self[i, i] for i in range(self.rows))
return fuzzy_and(x.is_positive for x in diagonal_entries)
def _has_nonnegative_diagonals(self):
diagonal_entries = (self[i, i] for i in range(self.rows))
return fuzzy_and(x.is_nonnegative for x in diagonal_entries)
def atoms(self, *types):
"""Returns the atoms that form the current object.
Examples
========
>>> from sympy.abc import x, y
>>> from sympy import Matrix
>>> Matrix([[x]])
Matrix([[x]])
>>> _.atoms()
{x}
>>> Matrix([[x, y], [y, x]])
Matrix([
[x, y],
[y, x]])
>>> _.atoms()
{x, y}
"""
types = tuple(t if isinstance(t, type) else type(t) for t in types)
if not types:
types = (Atom,)
return self._eval_atoms(*types)
@property
def free_symbols(self):
"""Returns the free symbols within the matrix.
Examples
========
>>> from sympy.abc import x
>>> from sympy import Matrix
>>> Matrix([[x], [1]]).free_symbols
{x}
"""
return self._eval_free_symbols()
def has(self, *patterns):
"""Test whether any subexpression matches any of the patterns.
Examples
========
>>> from sympy import Matrix, SparseMatrix, Float
>>> from sympy.abc import x, y
>>> A = Matrix(((1, x), (0.2, 3)))
>>> B = SparseMatrix(((1, x), (0.2, 3)))
>>> A.has(x)
True
>>> A.has(y)
False
>>> A.has(Float)
True
>>> B.has(x)
True
>>> B.has(y)
False
>>> B.has(Float)
True
"""
return self._eval_has(*patterns)
def is_anti_symmetric(self, simplify=True):
"""Check if matrix M is an antisymmetric matrix,
that is, M is a square matrix with all M[i, j] == -M[j, i].
When ``simplify=True`` (default), the sum M[i, j] + M[j, i] is
simplified before testing to see if it is zero. By default,
the SymPy simplify function is used. To use a custom function
set simplify to a function that accepts a single argument which
returns a simplified expression. To skip simplification, set
simplify to False but note that although this will be faster,
it may induce false negatives.
Examples
========
>>> from sympy import Matrix, symbols
>>> m = Matrix(2, 2, [0, 1, -1, 0])
>>> m
Matrix([
[ 0, 1],
[-1, 0]])
>>> m.is_anti_symmetric()
True
>>> x, y = symbols('x y')
>>> m = Matrix(2, 3, [0, 0, x, -y, 0, 0])
>>> m
Matrix([
[ 0, 0, x],
[-y, 0, 0]])
>>> m.is_anti_symmetric()
False
>>> from sympy.abc import x, y
>>> m = Matrix(3, 3, [0, x**2 + 2*x + 1, y,
... -(x + 1)**2, 0, x*y,
... -y, -x*y, 0])
Simplification of matrix elements is done by default so even
though two elements which should be equal and opposite would not
pass an equality test, the matrix is still reported as
anti-symmetric:
>>> m[0, 1] == -m[1, 0]
False
>>> m.is_anti_symmetric()
True
If ``simplify=False`` is used for the case when a Matrix is already
simplified, this will speed things up. Here, we see that without
simplification the matrix does not appear anti-symmetric:
>>> print(m.is_anti_symmetric(simplify=False))
None
But if the matrix were already expanded, then it would appear
anti-symmetric and simplification in the is_anti_symmetric routine
is not needed:
>>> m = m.expand()
>>> m.is_anti_symmetric(simplify=False)
True
"""
# accept custom simplification
simpfunc = simplify
if not isfunction(simplify):
simpfunc = _utilities_simplify if simplify else lambda x: x
if not self.is_square:
return False
return self._eval_is_anti_symmetric(simpfunc)
def is_diagonal(self):
"""Check if matrix is diagonal,
that is matrix in which the entries outside the main diagonal are all zero.
Examples
========
>>> from sympy import Matrix, diag
>>> m = Matrix(2, 2, [1, 0, 0, 2])
>>> m
Matrix([
[1, 0],
[0, 2]])
>>> m.is_diagonal()
True
>>> m = Matrix(2, 2, [1, 1, 0, 2])
>>> m
Matrix([
[1, 1],
[0, 2]])
>>> m.is_diagonal()
False
>>> m = diag(1, 2, 3)
>>> m
Matrix([
[1, 0, 0],
[0, 2, 0],
[0, 0, 3]])
>>> m.is_diagonal()
True
See Also
========
is_lower
is_upper
sympy.matrices.matrixbase.MatrixBase.is_diagonalizable
diagonalize
"""
return self._eval_is_diagonal()
@property
def is_weakly_diagonally_dominant(self):
r"""Tests if the matrix is row weakly diagonally dominant.
Explanation
===========
A $n, n$ matrix $A$ is row weakly diagonally dominant if
.. math::
\left|A_{i, i}\right| \ge \sum_{j = 0, j \neq i}^{n-1}
\left|A_{i, j}\right| \quad {\text{for all }}
i \in \{ 0, ..., n-1 \}
Examples
========
>>> from sympy import Matrix
>>> A = Matrix([[3, -2, 1], [1, -3, 2], [-1, 2, 4]])
>>> A.is_weakly_diagonally_dominant
True
>>> A = Matrix([[-2, 2, 1], [1, 3, 2], [1, -2, 0]])
>>> A.is_weakly_diagonally_dominant
False
>>> A = Matrix([[-4, 2, 1], [1, 6, 2], [1, -2, 5]])
>>> A.is_weakly_diagonally_dominant
True
Notes
=====
If you want to test whether a matrix is column diagonally
dominant, you can apply the test after transposing the matrix.
"""
if not self.is_square:
return False
rows, cols = self.shape
def test_row(i):
summation = self.zero
for j in range(cols):
if i != j:
summation += Abs(self[i, j])
return (Abs(self[i, i]) - summation).is_nonnegative
return fuzzy_and(test_row(i) for i in range(rows))
@property
def is_strongly_diagonally_dominant(self):
r"""Tests if the matrix is row strongly diagonally dominant.
Explanation
===========
A $n, n$ matrix $A$ is row strongly diagonally dominant if
.. math::
\left|A_{i, i}\right| > \sum_{j = 0, j \neq i}^{n-1}
\left|A_{i, j}\right| \quad {\text{for all }}
i \in \{ 0, ..., n-1 \}
Examples
========
>>> from sympy import Matrix
>>> A = Matrix([[3, -2, 1], [1, -3, 2], [-1, 2, 4]])
>>> A.is_strongly_diagonally_dominant
False
>>> A = Matrix([[-2, 2, 1], [1, 3, 2], [1, -2, 0]])
>>> A.is_strongly_diagonally_dominant
False
>>> A = Matrix([[-4, 2, 1], [1, 6, 2], [1, -2, 5]])
>>> A.is_strongly_diagonally_dominant
True
Notes
=====
If you want to test whether a matrix is column diagonally
dominant, you can apply the test after transposing the matrix.
"""
if not self.is_square:
return False
rows, cols = self.shape
def test_row(i):
summation = self.zero
for j in range(cols):
if i != j:
summation += Abs(self[i, j])
return (Abs(self[i, i]) - summation).is_positive
return fuzzy_and(test_row(i) for i in range(rows))
@property
def is_hermitian(self):
"""Checks if the matrix is Hermitian.
In a Hermitian matrix element i,j is the complex conjugate of
element j,i.
Examples
========
>>> from sympy import Matrix
>>> from sympy import I
>>> from sympy.abc import x
>>> a = Matrix([[1, I], [-I, 1]])
>>> a
Matrix([
[ 1, I],
[-I, 1]])
>>> a.is_hermitian
True
>>> a[0, 0] = 2*I
>>> a.is_hermitian
False
>>> a[0, 0] = x
>>> a.is_hermitian
>>> a[0, 1] = a[1, 0]*I
>>> a.is_hermitian
False
"""
if not self.is_square:
return False
return self._eval_is_matrix_hermitian(_utilities_simplify)
@property
def is_Identity(self) -> FuzzyBool:
if not self.is_square:
return False
return self._eval_is_Identity()
@property
def is_lower_hessenberg(self):
r"""Checks if the matrix is in the lower-Hessenberg form.
The lower hessenberg matrix has zero entries
above the first superdiagonal.
Examples
========
>>> from sympy import Matrix
>>> a = Matrix([[1, 2, 0, 0], [5, 2, 3, 0], [3, 4, 3, 7], [5, 6, 1, 1]])
>>> a
Matrix([
[1, 2, 0, 0],
[5, 2, 3, 0],
[3, 4, 3, 7],
[5, 6, 1, 1]])
>>> a.is_lower_hessenberg
True
See Also
========
is_upper_hessenberg
is_lower
"""
return self._eval_is_lower_hessenberg()
@property
def is_lower(self):
"""Check if matrix is a lower triangular matrix. True can be returned
even if the matrix is not square.
Examples
========
>>> from sympy import Matrix
>>> m = Matrix(2, 2, [1, 0, 0, 1])
>>> m
Matrix([
[1, 0],
[0, 1]])
>>> m.is_lower
True
>>> m = Matrix(4, 3, [0, 0, 0, 2, 0, 0, 1, 4, 0, 6, 6, 5])
>>> m
Matrix([
[0, 0, 0],
[2, 0, 0],
[1, 4, 0],
[6, 6, 5]])
>>> m.is_lower
True
>>> from sympy.abc import x, y
>>> m = Matrix(2, 2, [x**2 + y, y**2 + x, 0, x + y])
>>> m
Matrix([
[x**2 + y, x + y**2],
[ 0, x + y]])
>>> m.is_lower
False
See Also
========
is_upper
is_diagonal
is_lower_hessenberg
"""
return self._eval_is_lower()
@property
def is_square(self):
"""Checks if a matrix is square.
A matrix is square if the number of rows equals the number of columns.
The empty matrix is square by definition, since the number of rows and
the number of columns are both zero.
Examples
========
>>> from sympy import Matrix
>>> a = Matrix([[1, 2, 3], [4, 5, 6]])
>>> b = Matrix([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
>>> c = Matrix([])
>>> a.is_square
False
>>> b.is_square
True
>>> c.is_square
True
"""
return self.rows == self.cols
def is_symbolic(self):
"""Checks if any elements contain Symbols.
Examples
========
>>> from sympy import Matrix
>>> from sympy.abc import x, y
>>> M = Matrix([[x, y], [1, 0]])
>>> M.is_symbolic()
True
"""
return self._eval_is_symbolic()
def is_symmetric(self, simplify=True):
"""Check if matrix is symmetric matrix,
that is square matrix and is equal to its transpose.
By default, simplifications occur before testing symmetry.
They can be skipped using 'simplify=False'; while speeding things a bit,
this may however induce false negatives.
Examples
========
>>> from sympy import Matrix
>>> m = Matrix(2, 2, [0, 1, 1, 2])
>>> m
Matrix([
[0, 1],
[1, 2]])
>>> m.is_symmetric()
True
>>> m = Matrix(2, 2, [0, 1, 2, 0])
>>> m
Matrix([
[0, 1],
[2, 0]])
>>> m.is_symmetric()
False
>>> m = Matrix(2, 3, [0, 0, 0, 0, 0, 0])
>>> m
Matrix([
[0, 0, 0],
[0, 0, 0]])
>>> m.is_symmetric()
False
>>> from sympy.abc import x, y
>>> m = Matrix(3, 3, [1, x**2 + 2*x + 1, y, (x + 1)**2, 2, 0, y, 0, 3])
>>> m
Matrix([
[ 1, x**2 + 2*x + 1, y],
[(x + 1)**2, 2, 0],
[ y, 0, 3]])
>>> m.is_symmetric()
True
If the matrix is already simplified, you may speed-up is_symmetric()
test by using 'simplify=False'.
>>> bool(m.is_symmetric(simplify=False))
False
>>> m1 = m.expand()
>>> m1.is_symmetric(simplify=False)
True
"""
simpfunc = simplify
if not isfunction(simplify):
simpfunc = _utilities_simplify if simplify else lambda x: x
if not self.is_square:
return False
return self._eval_is_symmetric(simpfunc)
@property
def is_upper_hessenberg(self):
"""Checks if the matrix is the upper-Hessenberg form.
The upper hessenberg matrix has zero entries
below the first subdiagonal.
Examples
========
>>> from sympy import Matrix
>>> a = Matrix([[1, 4, 2, 3], [3, 4, 1, 7], [0, 2, 3, 4], [0, 0, 1, 3]])
>>> a
Matrix([
[1, 4, 2, 3],
[3, 4, 1, 7],
[0, 2, 3, 4],
[0, 0, 1, 3]])
>>> a.is_upper_hessenberg
True
See Also
========
is_lower_hessenberg
is_upper
"""
return self._eval_is_upper_hessenberg()
@property
def is_upper(self):
"""Check if matrix is an upper triangular matrix. True can be returned
even if the matrix is not square.
Examples
========
>>> from sympy import Matrix
>>> m = Matrix(2, 2, [1, 0, 0, 1])
>>> m
Matrix([
[1, 0],
[0, 1]])
>>> m.is_upper
True
>>> m = Matrix(4, 3, [5, 1, 9, 0, 4, 6, 0, 0, 5, 0, 0, 0])
>>> m
Matrix([
[5, 1, 9],
[0, 4, 6],
[0, 0, 5],
[0, 0, 0]])
>>> m.is_upper
True
>>> m = Matrix(2, 3, [4, 2, 5, 6, 1, 1])
>>> m
Matrix([
[4, 2, 5],
[6, 1, 1]])
>>> m.is_upper
False
See Also
========
is_lower
is_diagonal
is_upper_hessenberg
"""
return self._eval_is_upper()
@property
def is_zero_matrix(self):
"""Checks if a matrix is a zero matrix.
A matrix is zero if every element is zero. A matrix need not be square
to be considered zero. The empty matrix is zero by the principle of
vacuous truth. For a matrix that may or may not be zero (e.g.
contains a symbol), this will be None
Examples
========
>>> from sympy import Matrix, zeros
>>> from sympy.abc import x
>>> a = Matrix([[0, 0], [0, 0]])
>>> b = zeros(3, 4)
>>> c = Matrix([[0, 1], [0, 0]])
>>> d = Matrix([])
>>> e = Matrix([[x, 0], [0, 0]])
>>> a.is_zero_matrix
True
>>> b.is_zero_matrix
True
>>> c.is_zero_matrix
False
>>> d.is_zero_matrix
True
>>> e.is_zero_matrix
"""
return self._eval_is_zero_matrix()
def values(self):
"""Return non-zero values of self.
Examples
========
>>> from sympy import Matrix
>>> m = Matrix([[0, 1], [2, 3]])
>>> m.values()
[1, 2, 3]
See Also
========
iter_values
tolist
flat
"""
return self._eval_values()
def iter_values(self):
"""
Iterate over non-zero values of self.
Examples
========
>>> from sympy import Matrix
>>> m = Matrix([[0, 1], [2, 3]])
>>> list(m.iter_values())
[1, 2, 3]
See Also
========
values
"""
return self._eval_iter_values()
def iter_items(self):
"""Iterate over indices and values of nonzero items.
Examples
========
>>> from sympy import Matrix
>>> m = Matrix([[0, 1], [2, 3]])
>>> list(m.iter_items())
[((0, 1), 1), ((1, 0), 2), ((1, 1), 3)]
See Also
========
iter_values
todok
"""
return self._eval_iter_items()
def _eval_adjoint(self):
return self.transpose().conjugate()
def _eval_applyfunc(self, f):
cols = self.cols
size = self.rows*self.cols
dok = self.todok()
valmap = {v: f(v) for v in dok.values()}
if len(dok) < size and ((fzero := f(S.Zero)) is not S.Zero):
out_flat = [fzero]*size
for (i, j), v in dok.items():
out_flat[i*cols + j] = valmap[v]
out = self._new(self.rows, self.cols, out_flat)
else:
fdok = {ij: valmap[v] for ij, v in dok.items()}
out = self.from_dok(self.rows, self.cols, fdok)
return out
def _eval_as_real_imag(self): # type: ignore
return (self.applyfunc(re), self.applyfunc(im))
def _eval_conjugate(self):
return self.applyfunc(lambda x: x.conjugate())
def _eval_permute_cols(self, perm):
# apply the permutation to a list
mapping = list(perm)
def entry(i, j):
return self[i, mapping[j]]
return self._new(self.rows, self.cols, entry)
def _eval_permute_rows(self, perm):
# apply the permutation to a list
mapping = list(perm)
def entry(i, j):
return self[mapping[i], j]
return self._new(self.rows, self.cols, entry)
def _eval_trace(self):
return sum(self[i, i] for i in range(self.rows))
def _eval_transpose(self):
return self._new(self.cols, self.rows, lambda i, j: self[j, i])
def adjoint(self):
"""Conjugate transpose or Hermitian conjugation."""
return self._eval_adjoint()
def applyfunc(self, f):
"""Apply a function to each element of the matrix.
Examples
========
>>> from sympy import Matrix
>>> m = Matrix(2, 2, lambda i, j: i*2+j)
>>> m
Matrix([
[0, 1],
[2, 3]])
>>> m.applyfunc(lambda i: 2*i)
Matrix([
[0, 2],
[4, 6]])
"""
if not callable(f):
raise TypeError("`f` must be callable.")
return self._eval_applyfunc(f)
def as_real_imag(self, deep=True, **hints):
"""Returns a tuple containing the (real, imaginary) part of matrix."""
# XXX: Ignoring deep and hints...
return self._eval_as_real_imag()
def conjugate(self):
"""Return the by-element conjugation.
Examples
========
>>> from sympy import SparseMatrix, I
>>> a = SparseMatrix(((1, 2 + I), (3, 4), (I, -I)))
>>> a
Matrix([
[1, 2 + I],
[3, 4],
[I, -I]])
>>> a.C
Matrix([
[ 1, 2 - I],
[ 3, 4],
[-I, I]])
See Also
========
transpose: Matrix transposition
H: Hermite conjugation
sympy.matrices.matrixbase.MatrixBase.D: Dirac conjugation
"""
return self._eval_conjugate()
def doit(self, **hints):
return self.applyfunc(lambda x: x.doit(**hints))
def evalf(self, n=15, subs=None, maxn=100, chop=False, strict=False, quad=None, verbose=False):
"""Apply evalf() to each element of self."""
options = {'subs':subs, 'maxn':maxn, 'chop':chop, 'strict':strict,
'quad':quad, 'verbose':verbose}
return self.applyfunc(lambda i: i.evalf(n, **options))
def expand(self, deep=True, modulus=None, power_base=True, power_exp=True,
mul=True, log=True, multinomial=True, basic=True, **hints):
"""Apply core.function.expand to each entry of the matrix.
Examples
========
>>> from sympy.abc import x
>>> from sympy import Matrix
>>> Matrix(1, 1, [x*(x+1)])
Matrix([[x*(x + 1)]])
>>> _.expand()
Matrix([[x**2 + x]])
"""
return self.applyfunc(lambda x: x.expand(
deep, modulus, power_base, power_exp, mul, log, multinomial, basic,
**hints))
@property
def H(self):
"""Return Hermite conjugate.
Examples
========
>>> from sympy import Matrix, I
>>> m = Matrix((0, 1 + I, 2, 3))
>>> m
Matrix([
[ 0],
[1 + I],
[ 2],
[ 3]])
>>> m.H
Matrix([[0, 1 - I, 2, 3]])
See Also
========
conjugate: By-element conjugation
sympy.matrices.matrixbase.MatrixBase.D: Dirac conjugation
"""
return self.T.C
def permute(self, perm, orientation='rows', direction='forward'):
r"""Permute the rows or columns of a matrix by the given list of
swaps.
Parameters
==========
perm : Permutation, list, or list of lists
A representation for the permutation.
If it is ``Permutation``, it is used directly with some
resizing with respect to the matrix size.
If it is specified as list of lists,
(e.g., ``[[0, 1], [0, 2]]``), then the permutation is formed
from applying the product of cycles. The direction how the
cyclic product is applied is described in below.
If it is specified as a list, the list should represent
an array form of a permutation. (e.g., ``[1, 2, 0]``) which
would would form the swapping function
`0 \mapsto 1, 1 \mapsto 2, 2\mapsto 0`.
orientation : 'rows', 'cols'
A flag to control whether to permute the rows or the columns
direction : 'forward', 'backward'
A flag to control whether to apply the permutations from
the start of the list first, or from the back of the list
first.
For example, if the permutation specification is
``[[0, 1], [0, 2]]``,
If the flag is set to ``'forward'``, the cycle would be
formed as `0 \mapsto 2, 2 \mapsto 1, 1 \mapsto 0`.
If the flag is set to ``'backward'``, the cycle would be
formed as `0 \mapsto 1, 1 \mapsto 2, 2 \mapsto 0`.
If the argument ``perm`` is not in a form of list of lists,
this flag takes no effect.
Examples
========
>>> from sympy import eye
>>> M = eye(3)
>>> M.permute([[0, 1], [0, 2]], orientation='rows', direction='forward')
Matrix([
[0, 0, 1],
[1, 0, 0],
[0, 1, 0]])
>>> from sympy import eye
>>> M = eye(3)
>>> M.permute([[0, 1], [0, 2]], orientation='rows', direction='backward')
Matrix([
[0, 1, 0],
[0, 0, 1],
[1, 0, 0]])
Notes
=====
If a bijective function
`\sigma : \mathbb{N}_0 \rightarrow \mathbb{N}_0` denotes the
permutation.
If the matrix `A` is the matrix to permute, represented as
a horizontal or a vertical stack of vectors:
.. math::
A =
\begin{bmatrix}
a_0 \\ a_1 \\ \vdots \\ a_{n-1}
\end{bmatrix} =
\begin{bmatrix}
\alpha_0 & \alpha_1 & \cdots & \alpha_{n-1}
\end{bmatrix}
If the matrix `B` is the result, the permutation of matrix rows
is defined as:
.. math::
B := \begin{bmatrix}
a_{\sigma(0)} \\ a_{\sigma(1)} \\ \vdots \\ a_{\sigma(n-1)}
\end{bmatrix}
And the permutation of matrix columns is defined as:
.. math::
B := \begin{bmatrix}
\alpha_{\sigma(0)} & \alpha_{\sigma(1)} &
\cdots & \alpha_{\sigma(n-1)}
\end{bmatrix}
"""
from sympy.combinatorics import Permutation
# allow british variants and `columns`
if direction == 'forwards':
direction = 'forward'
if direction == 'backwards':
direction = 'backward'
if orientation == 'columns':
orientation = 'cols'
if direction not in ('forward', 'backward'):
raise TypeError("direction='{}' is an invalid kwarg. "
"Try 'forward' or 'backward'".format(direction))
if orientation not in ('rows', 'cols'):
raise TypeError("orientation='{}' is an invalid kwarg. "
"Try 'rows' or 'cols'".format(orientation))
if not isinstance(perm, (Permutation, Iterable)):
raise ValueError(
"{} must be a list, a list of lists, "
"or a SymPy permutation object.".format(perm))
# ensure all swaps are in range
max_index = self.rows if orientation == 'rows' else self.cols
if not all(0 <= t <= max_index for t in flatten(list(perm))):
raise IndexError("`swap` indices out of range.")
if perm and not isinstance(perm, Permutation) and \
isinstance(perm[0], Iterable):
if direction == 'forward':
perm = list(reversed(perm))
perm = Permutation(perm, size=max_index+1)
else:
perm = Permutation(perm, size=max_index+1)
if orientation == 'rows':
return self._eval_permute_rows(perm)
if orientation == 'cols':
return self._eval_permute_cols(perm)
def permute_cols(self, swaps, direction='forward'):
"""Alias for
``self.permute(swaps, orientation='cols', direction=direction)``
See Also
========
permute
"""
return self.permute(swaps, orientation='cols', direction=direction)
def permute_rows(self, swaps, direction='forward'):
"""Alias for
``self.permute(swaps, orientation='rows', direction=direction)``
See Also
========
permute
"""
return self.permute(swaps, orientation='rows', direction=direction)
def refine(self, assumptions=True):
"""Apply refine to each element of the matrix.
Examples
========
>>> from sympy import Symbol, Matrix, Abs, sqrt, Q
>>> x = Symbol('x')
>>> Matrix([[Abs(x)**2, sqrt(x**2)],[sqrt(x**2), Abs(x)**2]])
Matrix([
[ Abs(x)**2, sqrt(x**2)],
[sqrt(x**2), Abs(x)**2]])
>>> _.refine(Q.real(x))
Matrix([
[ x**2, Abs(x)],
[Abs(x), x**2]])
"""
return self.applyfunc(lambda x: refine(x, assumptions))
def replace(self, F, G, map=False, simultaneous=True, exact=None):
"""Replaces Function F in Matrix entries with Function G.
Examples
========
>>> from sympy import symbols, Function, Matrix
>>> F, G = symbols('F, G', cls=Function)
>>> M = Matrix(2, 2, lambda i, j: F(i+j)) ; M
Matrix([
[F(0), F(1)],
[F(1), F(2)]])
>>> N = M.replace(F,G)
>>> N
Matrix([
[G(0), G(1)],
[G(1), G(2)]])
"""
kwargs = {'map': map, 'simultaneous': simultaneous, 'exact': exact}
if map:
d = {}
def func(eij):
eij, dij = eij.replace(F, G, **kwargs)
d.update(dij)
return eij
M = self.applyfunc(func)
return M, d
else:
return self.applyfunc(lambda i: i.replace(F, G, **kwargs))
def rot90(self, k=1):
"""Rotates Matrix by 90 degrees
Parameters
==========
k : int
Specifies how many times the matrix is rotated by 90 degrees
(clockwise when positive, counter-clockwise when negative).
Examples
========
>>> from sympy import Matrix, symbols
>>> A = Matrix(2, 2, symbols('a:d'))
>>> A
Matrix([
[a, b],
[c, d]])
Rotating the matrix clockwise one time:
>>> A.rot90(1)
Matrix([
[c, a],
[d, b]])
Rotating the matrix anticlockwise two times:
>>> A.rot90(-2)
Matrix([
[d, c],
[b, a]])
"""
mod = k%4
if mod == 0:
return self
if mod == 1:
return self[::-1, ::].T
if mod == 2:
return self[::-1, ::-1]
if mod == 3:
return self[::, ::-1].T
def simplify(self, **kwargs):
"""Apply simplify to each element of the matrix.
Examples
========
>>> from sympy.abc import x, y
>>> from sympy import SparseMatrix, sin, cos
>>> SparseMatrix(1, 1, [x*sin(y)**2 + x*cos(y)**2])
Matrix([[x*sin(y)**2 + x*cos(y)**2]])
>>> _.simplify()
Matrix([[x]])
"""
return self.applyfunc(lambda x: x.simplify(**kwargs))
def subs(self, *args, **kwargs): # should mirror core.basic.subs
"""Return a new matrix with subs applied to each entry.
Examples
========
>>> from sympy.abc import x, y
>>> from sympy import SparseMatrix, Matrix
>>> SparseMatrix(1, 1, [x])
Matrix([[x]])
>>> _.subs(x, y)
Matrix([[y]])
>>> Matrix(_).subs(y, x)
Matrix([[x]])
"""
if len(args) == 1 and not isinstance(args[0], (dict, set)) and iter(args[0]) and not is_sequence(args[0]):
args = (list(args[0]),)
return self.applyfunc(lambda x: x.subs(*args, **kwargs))
def trace(self):
"""
Returns the trace of a square matrix i.e. the sum of the
diagonal elements.
Examples
========
>>> from sympy import Matrix
>>> A = Matrix(2, 2, [1, 2, 3, 4])
>>> A.trace()
5
"""
if self.rows != self.cols:
raise NonSquareMatrixError()
return self._eval_trace()
def transpose(self):
"""
Returns the transpose of the matrix.
Examples
========
>>> from sympy import Matrix
>>> A = Matrix(2, 2, [1, 2, 3, 4])
>>> A.transpose()
Matrix([
[1, 3],
[2, 4]])
>>> from sympy import Matrix, I
>>> m=Matrix(((1, 2+I), (3, 4)))
>>> m
Matrix([
[1, 2 + I],
[3, 4]])
>>> m.transpose()
Matrix([
[ 1, 3],
[2 + I, 4]])
>>> m.T == m.transpose()
True
See Also
========
conjugate: By-element conjugation
"""
return self._eval_transpose()
@property
def T(self):
'''Matrix transposition'''
return self.transpose()
@property
def C(self):
'''By-element conjugation'''
return self.conjugate()
def n(self, *args, **kwargs):
"""Apply evalf() to each element of self."""
return self.evalf(*args, **kwargs)
def xreplace(self, rule): # should mirror core.basic.xreplace
"""Return a new matrix with xreplace applied to each entry.
Examples
========
>>> from sympy.abc import x, y
>>> from sympy import SparseMatrix, Matrix
>>> SparseMatrix(1, 1, [x])
Matrix([[x]])
>>> _.xreplace({x: y})
Matrix([[y]])
>>> Matrix(_).xreplace({y: x})
Matrix([[x]])
"""
return self.applyfunc(lambda x: x.xreplace(rule))
def _eval_simplify(self, **kwargs):
# XXX: We can't use self.simplify here as mutable subclasses will
# override simplify and have it return None
return self.applyfunc(lambda x: x.simplify(**kwargs))
def _eval_trigsimp(self, **opts):
from sympy.simplify.trigsimp import trigsimp
return self.applyfunc(lambda x: trigsimp(x, **opts))
def upper_triangular(self, k=0):
"""Return the elements on and above the kth diagonal of a matrix.
If k is not specified then simply returns upper-triangular portion
of a matrix
Examples
========
>>> from sympy import ones
>>> A = ones(4)
>>> A.upper_triangular()
Matrix([
[1, 1, 1, 1],
[0, 1, 1, 1],
[0, 0, 1, 1],
[0, 0, 0, 1]])
>>> A.upper_triangular(2)
Matrix([
[0, 0, 1, 1],
[0, 0, 0, 1],
[0, 0, 0, 0],
[0, 0, 0, 0]])
>>> A.upper_triangular(-1)
Matrix([
[1, 1, 1, 1],
[1, 1, 1, 1],
[0, 1, 1, 1],
[0, 0, 1, 1]])
"""
def entry(i, j):
return self[i, j] if i + k <= j else self.zero
return self._new(self.rows, self.cols, entry)
def lower_triangular(self, k=0):
"""Return the elements on and below the kth diagonal of a matrix.
If k is not specified then simply returns lower-triangular portion
of a matrix
Examples
========
>>> from sympy import ones
>>> A = ones(4)
>>> A.lower_triangular()
Matrix([
[1, 0, 0, 0],
[1, 1, 0, 0],
[1, 1, 1, 0],
[1, 1, 1, 1]])
>>> A.lower_triangular(-2)
Matrix([
[0, 0, 0, 0],
[0, 0, 0, 0],
[1, 0, 0, 0],
[1, 1, 0, 0]])
>>> A.lower_triangular(1)
Matrix([
[1, 1, 0, 0],
[1, 1, 1, 0],
[1, 1, 1, 1],
[1, 1, 1, 1]])
"""
def entry(i, j):
return self[i, j] if i + k >= j else self.zero
return self._new(self.rows, self.cols, entry)
def _eval_Abs(self):
return self._new(self.rows, self.cols, lambda i, j: Abs(self[i, j]))
def _eval_add(self, other):
return self._new(self.rows, self.cols,
lambda i, j: self[i, j] + other[i, j])
def _eval_matrix_mul(self, other):
def entry(i, j):
vec = [self[i,k]*other[k,j] for k in range(self.cols)]
try:
return Add(*vec)
except (TypeError, SympifyError):
# Some matrices don't work with `sum` or `Add`
# They don't work with `sum` because `sum` tries to add `0`
# Fall back to a safe way to multiply if the `Add` fails.
return reduce(lambda a, b: a + b, vec)
return self._new(self.rows, other.cols, entry)
def _eval_matrix_mul_elementwise(self, other):
return self._new(self.rows, self.cols, lambda i, j: self[i,j]*other[i,j])
def _eval_matrix_rmul(self, other):
def entry(i, j):
return sum(other[i,k]*self[k,j] for k in range(other.cols))
return self._new(other.rows, self.cols, entry)
def _eval_pow_by_recursion(self, num):
if num == 1:
return self
if num % 2 == 1:
a, b = self, self._eval_pow_by_recursion(num - 1)
else:
a = b = self._eval_pow_by_recursion(num // 2)
return a.multiply(b)
def _eval_pow_by_cayley(self, exp):
from sympy.discrete.recurrences import linrec_coeffs
row = self.shape[0]
p = self.charpoly()
coeffs = (-p).all_coeffs()[1:]
coeffs = linrec_coeffs(coeffs, exp)
new_mat = self.eye(row)
ans = self.zeros(row)
for i in range(row):
ans += coeffs[i]*new_mat
new_mat *= self
return ans
def _eval_pow_by_recursion_dotprodsimp(self, num, prevsimp=None):
if prevsimp is None:
prevsimp = [True]*len(self)
if num == 1:
return self
if num % 2 == 1:
a, b = self, self._eval_pow_by_recursion_dotprodsimp(num - 1,
prevsimp=prevsimp)
else:
a = b = self._eval_pow_by_recursion_dotprodsimp(num // 2,
prevsimp=prevsimp)
m = a.multiply(b, dotprodsimp=False)
lenm = len(m)
elems = [None]*lenm
for i in range(lenm):
if prevsimp[i]:
elems[i], prevsimp[i] = _dotprodsimp(m[i], withsimp=True)
else:
elems[i] = m[i]
return m._new(m.rows, m.cols, elems)
def _eval_scalar_mul(self, other):
return self._new(self.rows, self.cols, lambda i, j: self[i,j]*other)
def _eval_scalar_rmul(self, other):
return self._new(self.rows, self.cols, lambda i, j: other*self[i,j])
def _eval_Mod(self, other):
return self._new(self.rows, self.cols, lambda i, j: Mod(self[i, j], other))
# Python arithmetic functions
def __abs__(self):
"""Returns a new matrix with entry-wise absolute values."""
return self._eval_Abs()
@call_highest_priority('__radd__')
def __add__(self, other):
"""Return self + other, raising ShapeError if shapes do not match."""
other, T = _coerce_operand(self, other)
if T != "is_matrix":
return NotImplemented
if self.shape != other.shape:
raise ShapeError(f"Matrix size mismatch: {self.shape} + {other.shape}.")
# Unify matrix types
a, b = self, other
if a.__class__ != classof(a, b):
b, a = a, b
return a._eval_add(b)
@call_highest_priority('__rtruediv__')
def __truediv__(self, other):
return self * (self.one / other)
@call_highest_priority('__rmatmul__')
def __matmul__(self, other):
self, other, T = _unify_with_other(self, other)
if T != "is_matrix":
return NotImplemented
return self.__mul__(other)
def __mod__(self, other):
return self.applyfunc(lambda x: x % other)
@call_highest_priority('__rmul__')
def __mul__(self, other):
"""Return self*other where other is either a scalar or a matrix
of compatible dimensions.
Examples
========
>>> from sympy import Matrix
>>> A = Matrix([[1, 2, 3], [4, 5, 6]])
>>> 2*A == A*2 == Matrix([[2, 4, 6], [8, 10, 12]])
True
>>> B = Matrix([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
>>> A*B
Matrix([
[30, 36, 42],
[66, 81, 96]])
>>> B*A
Traceback (most recent call last):
...
ShapeError: Matrices size mismatch.
>>>
See Also
========
matrix_multiply_elementwise
"""
return self.multiply(other)
def multiply(self, other, dotprodsimp=None):
"""Same as __mul__() but with optional simplification.
Parameters
==========
dotprodsimp : bool, optional
Specifies whether intermediate term algebraic simplification is used
during matrix multiplications to control expression blowup and thus
speed up calculation. Default is off.
"""
isimpbool = _get_intermediate_simp_bool(False, dotprodsimp)
self, other, T = _unify_with_other(self, other)
if T == "possible_scalar":
try:
return self._eval_scalar_mul(other)
except TypeError:
return NotImplemented
elif T == "is_matrix":
if self.shape[1] != other.shape[0]:
raise ShapeError(f"Matrix size mismatch: {self.shape} * {other.shape}.")
m = self._eval_matrix_mul(other)
if isimpbool:
m = m._new(m.rows, m.cols, [_dotprodsimp(e) for e in m])
return m
else:
return NotImplemented
def multiply_elementwise(self, other):
"""Return the Hadamard product (elementwise product) of A and B
Examples
========
>>> from sympy import Matrix
>>> A = Matrix([[0, 1, 2], [3, 4, 5]])
>>> B = Matrix([[1, 10, 100], [100, 10, 1]])
>>> A.multiply_elementwise(B)
Matrix([
[ 0, 10, 200],
[300, 40, 5]])
See Also
========
sympy.matrices.matrixbase.MatrixBase.cross
sympy.matrices.matrixbase.MatrixBase.dot
multiply
"""
if self.shape != other.shape:
raise ShapeError("Matrix shapes must agree {} != {}".format(self.shape, other.shape))
return self._eval_matrix_mul_elementwise(other)
def __neg__(self):
return self._eval_scalar_mul(-1)
@call_highest_priority('__rpow__')
def __pow__(self, exp):
"""Return self**exp a scalar or symbol."""
return self.pow(exp)
def pow(self, exp, method=None):
r"""Return self**exp a scalar or symbol.
Parameters
==========
method : multiply, mulsimp, jordan, cayley
If multiply then it returns exponentiation using recursion.
If jordan then Jordan form exponentiation will be used.
If cayley then the exponentiation is done using Cayley-Hamilton
theorem.
If mulsimp then the exponentiation is done using recursion
with dotprodsimp. This specifies whether intermediate term
algebraic simplification is used during naive matrix power to
control expression blowup and thus speed up calculation.
If None, then it heuristically decides which method to use.
"""
if method is not None and method not in ['multiply', 'mulsimp', 'jordan', 'cayley']:
raise TypeError('No such method')
if self.rows != self.cols:
raise NonSquareMatrixError()
a = self
jordan_pow = getattr(a, '_matrix_pow_by_jordan_blocks', None)
exp = sympify(exp)
if exp.is_zero:
return a._new(a.rows, a.cols, lambda i, j: int(i == j))
if exp == 1:
return a
diagonal = getattr(a, 'is_diagonal', None)
if diagonal is not None and diagonal():
return a._new(a.rows, a.cols, lambda i, j: a[i,j]**exp if i == j else 0)
if exp.is_Number and exp % 1 == 0:
if a.rows == 1:
return a._new([[a[0]**exp]])
if exp < 0:
exp = -exp
a = a.inv()
# When certain conditions are met,
# Jordan block algorithm is faster than
# computation by recursion.
if method == 'jordan':
try:
return jordan_pow(exp)
except MatrixError:
if method == 'jordan':
raise
elif method == 'cayley':
if not exp.is_Number or exp % 1 != 0:
raise ValueError("cayley method is only valid for integer powers")
return a._eval_pow_by_cayley(exp)
elif method == "mulsimp":
if not exp.is_Number or exp % 1 != 0:
raise ValueError("mulsimp method is only valid for integer powers")
return a._eval_pow_by_recursion_dotprodsimp(exp)
elif method == "multiply":
if not exp.is_Number or exp % 1 != 0:
raise ValueError("multiply method is only valid for integer powers")
return a._eval_pow_by_recursion(exp)
elif method is None and exp.is_Number and exp % 1 == 0:
if exp.is_Float:
exp = Integer(exp)
# Decide heuristically which method to apply
if a.rows == 2 and exp > 100000:
return jordan_pow(exp)
elif _get_intermediate_simp_bool(True, None):
return a._eval_pow_by_recursion_dotprodsimp(exp)
elif exp > 10000:
return a._eval_pow_by_cayley(exp)
else:
return a._eval_pow_by_recursion(exp)
if jordan_pow:
try:
return jordan_pow(exp)
except NonInvertibleMatrixError:
# Raised by jordan_pow on zero determinant matrix unless exp is
# definitely known to be a non-negative integer.
# Here we raise if n is definitely not a non-negative integer
# but otherwise we can leave this as an unevaluated MatPow.
if exp.is_integer is False or exp.is_nonnegative is False:
raise
from sympy.matrices.expressions import MatPow
return MatPow(a, exp)
@call_highest_priority('__add__')
def __radd__(self, other):
return self + other
@call_highest_priority('__matmul__')
def __rmatmul__(self, other):
self, other, T = _unify_with_other(self, other)
if T != "is_matrix":
return NotImplemented
return self.__rmul__(other)
@call_highest_priority('__mul__')
def __rmul__(self, other):
return self.rmultiply(other)
def rmultiply(self, other, dotprodsimp=None):
"""Same as __rmul__() but with optional simplification.
Parameters
==========
dotprodsimp : bool, optional
Specifies whether intermediate term algebraic simplification is used
during matrix multiplications to control expression blowup and thus
speed up calculation. Default is off.
"""
isimpbool = _get_intermediate_simp_bool(False, dotprodsimp)
self, other, T = _unify_with_other(self, other)
if T == "possible_scalar":
try:
return self._eval_scalar_rmul(other)
except TypeError:
return NotImplemented
elif T == "is_matrix":
if self.shape[0] != other.shape[1]:
raise ShapeError("Matrix size mismatch.")
m = self._eval_matrix_rmul(other)
if isimpbool:
return m._new(m.rows, m.cols, [_dotprodsimp(e) for e in m])
return m
else:
return NotImplemented
@call_highest_priority('__sub__')
def __rsub__(self, a):
return (-self) + a
@call_highest_priority('__rsub__')
def __sub__(self, a):
return self + (-a)
def _eval_det_bareiss(self, iszerofunc=_is_zero_after_expand_mul):
return _det_bareiss(self, iszerofunc=iszerofunc)
def _eval_det_berkowitz(self):
return _det_berkowitz(self)
def _eval_det_lu(self, iszerofunc=_iszero, simpfunc=None):
return _det_LU(self, iszerofunc=iszerofunc, simpfunc=simpfunc)
def _eval_det_bird(self):
return _det_bird(self)
def _eval_det_laplace(self):
return _det_laplace(self)
def _eval_determinant(self): # for expressions.determinant.Determinant
return _det(self)
def adjugate(self, method="berkowitz"):
return _adjugate(self, method=method)
def charpoly(self, x='lambda', simplify=_utilities_simplify):
return _charpoly(self, x=x, simplify=simplify)
def cofactor(self, i, j, method="berkowitz"):
return _cofactor(self, i, j, method=method)
def cofactor_matrix(self, method="berkowitz"):
return _cofactor_matrix(self, method=method)
def det(self, method="bareiss", iszerofunc=None):
return _det(self, method=method, iszerofunc=iszerofunc)
def per(self):
return _per(self)
def minor(self, i, j, method="berkowitz"):
return _minor(self, i, j, method=method)
def minor_submatrix(self, i, j):
return _minor_submatrix(self, i, j)
_find_reasonable_pivot.__doc__ = _find_reasonable_pivot.__doc__
_find_reasonable_pivot_naive.__doc__ = _find_reasonable_pivot_naive.__doc__
_eval_det_bareiss.__doc__ = _det_bareiss.__doc__
_eval_det_berkowitz.__doc__ = _det_berkowitz.__doc__
_eval_det_bird.__doc__ = _det_bird.__doc__
_eval_det_laplace.__doc__ = _det_laplace.__doc__
_eval_det_lu.__doc__ = _det_LU.__doc__
_eval_determinant.__doc__ = _det.__doc__
adjugate.__doc__ = _adjugate.__doc__
charpoly.__doc__ = _charpoly.__doc__
cofactor.__doc__ = _cofactor.__doc__
cofactor_matrix.__doc__ = _cofactor_matrix.__doc__
det.__doc__ = _det.__doc__
per.__doc__ = _per.__doc__
minor.__doc__ = _minor.__doc__
minor_submatrix.__doc__ = _minor_submatrix.__doc__
def echelon_form(self, iszerofunc=_iszero, simplify=False, with_pivots=False):
return _echelon_form(self, iszerofunc=iszerofunc, simplify=simplify,
with_pivots=with_pivots)
@property
def is_echelon(self):
return _is_echelon(self)
def rank(self, iszerofunc=_iszero, simplify=False):
return _rank(self, iszerofunc=iszerofunc, simplify=simplify)
def rref_rhs(self, rhs):
"""Return reduced row-echelon form of matrix, matrix showing
rhs after reduction steps. ``rhs`` must have the same number
of rows as ``self``.
Examples
========
>>> from sympy import Matrix, symbols
>>> r1, r2 = symbols('r1 r2')
>>> Matrix([[1, 1], [2, 1]]).rref_rhs(Matrix([r1, r2]))
(Matrix([
[1, 0],
[0, 1]]), Matrix([
[ -r1 + r2],
[2*r1 - r2]]))
"""
r, _ = _rref(self.hstack(self, self.eye(self.rows), rhs))
return r[:, :self.cols], r[:, -rhs.cols:]
def rref(self, iszerofunc=_iszero, simplify=False, pivots=True,
normalize_last=True):
return _rref(self, iszerofunc=iszerofunc, simplify=simplify,
pivots=pivots, normalize_last=normalize_last)
echelon_form.__doc__ = _echelon_form.__doc__
is_echelon.__doc__ = _is_echelon.__doc__
rank.__doc__ = _rank.__doc__
rref.__doc__ = _rref.__doc__
def _normalize_op_args(self, op, col, k, col1, col2, error_str="col"):
"""Validate the arguments for a row/column operation. ``error_str``
can be one of "row" or "col" depending on the arguments being parsed."""
if op not in ["n->kn", "n<->m", "n->n+km"]:
raise ValueError("Unknown {} operation '{}'. Valid col operations "
"are 'n->kn', 'n<->m', 'n->n+km'".format(error_str, op))
# define self_col according to error_str
self_cols = self.cols if error_str == 'col' else self.rows
# normalize and validate the arguments
if op == "n->kn":
col = col if col is not None else col1
if col is None or k is None:
raise ValueError("For a {0} operation 'n->kn' you must provide the "
"kwargs `{0}` and `k`".format(error_str))
if not 0 <= col < self_cols:
raise ValueError("This matrix does not have a {} '{}'".format(error_str, col))
elif op == "n<->m":
# we need two cols to swap. It does not matter
# how they were specified, so gather them together and
# remove `None`
cols = {col, k, col1, col2}.difference([None])
if len(cols) > 2:
# maybe the user left `k` by mistake?
cols = {col, col1, col2}.difference([None])
if len(cols) != 2:
raise ValueError("For a {0} operation 'n<->m' you must provide the "
"kwargs `{0}1` and `{0}2`".format(error_str))
col1, col2 = cols
if not 0 <= col1 < self_cols:
raise ValueError("This matrix does not have a {} '{}'".format(error_str, col1))
if not 0 <= col2 < self_cols:
raise ValueError("This matrix does not have a {} '{}'".format(error_str, col2))
elif op == "n->n+km":
col = col1 if col is None else col
col2 = col1 if col2 is None else col2
if col is None or col2 is None or k is None:
raise ValueError("For a {0} operation 'n->n+km' you must provide the "
"kwargs `{0}`, `k`, and `{0}2`".format(error_str))
if col == col2:
raise ValueError("For a {0} operation 'n->n+km' `{0}` and `{0}2` must "
"be different.".format(error_str))
if not 0 <= col < self_cols:
raise ValueError("This matrix does not have a {} '{}'".format(error_str, col))
if not 0 <= col2 < self_cols:
raise ValueError("This matrix does not have a {} '{}'".format(error_str, col2))
else:
raise ValueError('invalid operation %s' % repr(op))
return op, col, k, col1, col2
def _eval_col_op_multiply_col_by_const(self, col, k):
def entry(i, j):
if j == col:
return k * self[i, j]
return self[i, j]
return self._new(self.rows, self.cols, entry)
def _eval_col_op_swap(self, col1, col2):
def entry(i, j):
if j == col1:
return self[i, col2]
elif j == col2:
return self[i, col1]
return self[i, j]
return self._new(self.rows, self.cols, entry)
def _eval_col_op_add_multiple_to_other_col(self, col, k, col2):
def entry(i, j):
if j == col:
return self[i, j] + k * self[i, col2]
return self[i, j]
return self._new(self.rows, self.cols, entry)
def _eval_row_op_swap(self, row1, row2):
def entry(i, j):
if i == row1:
return self[row2, j]
elif i == row2:
return self[row1, j]
return self[i, j]
return self._new(self.rows, self.cols, entry)
def _eval_row_op_multiply_row_by_const(self, row, k):
def entry(i, j):
if i == row:
return k * self[i, j]
return self[i, j]
return self._new(self.rows, self.cols, entry)
def _eval_row_op_add_multiple_to_other_row(self, row, k, row2):
def entry(i, j):
if i == row:
return self[i, j] + k * self[row2, j]
return self[i, j]
return self._new(self.rows, self.cols, entry)
def elementary_col_op(self, op="n->kn", col=None, k=None, col1=None, col2=None):
"""Performs the elementary column operation `op`.
`op` may be one of
* ``"n->kn"`` (column n goes to k*n)
* ``"n<->m"`` (swap column n and column m)
* ``"n->n+km"`` (column n goes to column n + k*column m)
Parameters
==========
op : string; the elementary row operation
col : the column to apply the column operation
k : the multiple to apply in the column operation
col1 : one column of a column swap
col2 : second column of a column swap or column "m" in the column operation
"n->n+km"
"""
op, col, k, col1, col2 = self._normalize_op_args(op, col, k, col1, col2, "col")
# now that we've validated, we're all good to dispatch
if op == "n->kn":
return self._eval_col_op_multiply_col_by_const(col, k)
if op == "n<->m":
return self._eval_col_op_swap(col1, col2)
if op == "n->n+km":
return self._eval_col_op_add_multiple_to_other_col(col, k, col2)
def elementary_row_op(self, op="n->kn", row=None, k=None, row1=None, row2=None):
"""Performs the elementary row operation `op`.
`op` may be one of
* ``"n->kn"`` (row n goes to k*n)
* ``"n<->m"`` (swap row n and row m)
* ``"n->n+km"`` (row n goes to row n + k*row m)
Parameters
==========
op : string; the elementary row operation
row : the row to apply the row operation
k : the multiple to apply in the row operation
row1 : one row of a row swap
row2 : second row of a row swap or row "m" in the row operation
"n->n+km"
"""
op, row, k, row1, row2 = self._normalize_op_args(op, row, k, row1, row2, "row")
# now that we've validated, we're all good to dispatch
if op == "n->kn":
return self._eval_row_op_multiply_row_by_const(row, k)
if op == "n<->m":
return self._eval_row_op_swap(row1, row2)
if op == "n->n+km":
return self._eval_row_op_add_multiple_to_other_row(row, k, row2)
def columnspace(self, simplify=False):
return _columnspace(self, simplify=simplify)
def nullspace(self, simplify=False, iszerofunc=_iszero):
return _nullspace(self, simplify=simplify, iszerofunc=iszerofunc)
def rowspace(self, simplify=False):
return _rowspace(self, simplify=simplify)
# This is a classmethod but is converted to such later in order to allow
# assignment of __doc__ since that does not work for already wrapped
# classmethods in Python 3.6.
def orthogonalize(cls, *vecs, **kwargs):
return _orthogonalize(cls, *vecs, **kwargs)
columnspace.__doc__ = _columnspace.__doc__
nullspace.__doc__ = _nullspace.__doc__
rowspace.__doc__ = _rowspace.__doc__
orthogonalize.__doc__ = _orthogonalize.__doc__
orthogonalize = classmethod(orthogonalize) # type:ignore
def eigenvals(self, error_when_incomplete=True, **flags):
return _eigenvals(self, error_when_incomplete=error_when_incomplete, **flags)
def eigenvects(self, error_when_incomplete=True, iszerofunc=_iszero, **flags):
return _eigenvects(self, error_when_incomplete=error_when_incomplete,
iszerofunc=iszerofunc, **flags)
def is_diagonalizable(self, reals_only=False, **kwargs):
return _is_diagonalizable(self, reals_only=reals_only, **kwargs)
def diagonalize(self, reals_only=False, sort=False, normalize=False):
return _diagonalize(self, reals_only=reals_only, sort=sort,
normalize=normalize)
def bidiagonalize(self, upper=True):
return _bidiagonalize(self, upper=upper)
def bidiagonal_decomposition(self, upper=True):
return _bidiagonal_decomposition(self, upper=upper)
@property
def is_positive_definite(self):
return _is_positive_definite(self)
@property
def is_positive_semidefinite(self):
return _is_positive_semidefinite(self)
@property
def is_negative_definite(self):
return _is_negative_definite(self)
@property
def is_negative_semidefinite(self):
return _is_negative_semidefinite(self)
@property
def is_indefinite(self):
return _is_indefinite(self)
def jordan_form(self, calc_transform=True, **kwargs):
return _jordan_form(self, calc_transform=calc_transform, **kwargs)
def left_eigenvects(self, **flags):
return _left_eigenvects(self, **flags)
def singular_values(self):
return _singular_values(self)
eigenvals.__doc__ = _eigenvals.__doc__
eigenvects.__doc__ = _eigenvects.__doc__
is_diagonalizable.__doc__ = _is_diagonalizable.__doc__
diagonalize.__doc__ = _diagonalize.__doc__
is_positive_definite.__doc__ = _is_positive_definite.__doc__
is_positive_semidefinite.__doc__ = _is_positive_semidefinite.__doc__
is_negative_definite.__doc__ = _is_negative_definite.__doc__
is_negative_semidefinite.__doc__ = _is_negative_semidefinite.__doc__
is_indefinite.__doc__ = _is_indefinite.__doc__
jordan_form.__doc__ = _jordan_form.__doc__
left_eigenvects.__doc__ = _left_eigenvects.__doc__
singular_values.__doc__ = _singular_values.__doc__
bidiagonalize.__doc__ = _bidiagonalize.__doc__
bidiagonal_decomposition.__doc__ = _bidiagonal_decomposition.__doc__
def diff(self, *args, evaluate=True, **kwargs):
"""Calculate the derivative of each element in the matrix.
Examples
========
>>> from sympy import Matrix
>>> from sympy.abc import x, y
>>> M = Matrix([[x, y], [1, 0]])
>>> M.diff(x)
Matrix([
[1, 0],
[0, 0]])
See Also
========
integrate
limit
"""
# XXX this should be handled here rather than in Derivative
from sympy.tensor.array.array_derivatives import ArrayDerivative
deriv = ArrayDerivative(self, *args, evaluate=evaluate)
# XXX This can rather changed to always return immutable matrix
if not isinstance(self, Basic) and evaluate:
return deriv.as_mutable()
return deriv
def _eval_derivative(self, arg):
return self.applyfunc(lambda x: x.diff(arg))
def integrate(self, *args, **kwargs):
"""Integrate each element of the matrix. ``args`` will
be passed to the ``integrate`` function.
Examples
========
>>> from sympy import Matrix
>>> from sympy.abc import x, y
>>> M = Matrix([[x, y], [1, 0]])
>>> M.integrate((x, ))
Matrix([
[x**2/2, x*y],
[ x, 0]])
>>> M.integrate((x, 0, 2))
Matrix([
[2, 2*y],
[2, 0]])
See Also
========
limit
diff
"""
return self.applyfunc(lambda x: x.integrate(*args, **kwargs))
def jacobian(self, X):
"""Calculates the Jacobian matrix (derivative of a vector-valued function).
Parameters
==========
``self`` : vector of expressions representing functions f_i(x_1, ..., x_n).
X : set of x_i's in order, it can be a list or a Matrix
Both ``self`` and X can be a row or a column matrix in any order
(i.e., jacobian() should always work).
Examples
========
>>> from sympy import sin, cos, Matrix
>>> from sympy.abc import rho, phi
>>> X = Matrix([rho*cos(phi), rho*sin(phi), rho**2])
>>> Y = Matrix([rho, phi])
>>> X.jacobian(Y)
Matrix([
[cos(phi), -rho*sin(phi)],
[sin(phi), rho*cos(phi)],
[ 2*rho, 0]])
>>> X = Matrix([rho*cos(phi), rho*sin(phi)])
>>> X.jacobian(Y)
Matrix([
[cos(phi), -rho*sin(phi)],
[sin(phi), rho*cos(phi)]])
See Also
========
hessian
wronskian
"""
from sympy.matrices.matrixbase import MatrixBase
if not isinstance(X, MatrixBase):
X = self._new(X)
# Both X and ``self`` can be a row or a column matrix, so we need to make
# sure all valid combinations work, but everything else fails:
if self.shape[0] == 1:
m = self.shape[1]
elif self.shape[1] == 1:
m = self.shape[0]
else:
raise TypeError("``self`` must be a row or a column matrix")
if X.shape[0] == 1:
n = X.shape[1]
elif X.shape[1] == 1:
n = X.shape[0]
else:
raise TypeError("X must be a row or a column matrix")
# m is the number of functions and n is the number of variables
# computing the Jacobian is now easy:
return self._new(m, n, lambda j, i: self[j].diff(X[i]))
def limit(self, *args):
"""Calculate the limit of each element in the matrix.
``args`` will be passed to the ``limit`` function.
Examples
========
>>> from sympy import Matrix
>>> from sympy.abc import x, y
>>> M = Matrix([[x, y], [1, 0]])
>>> M.limit(x, 2)
Matrix([
[2, y],
[1, 0]])
See Also
========
integrate
diff
"""
return self.applyfunc(lambda x: x.limit(*args))
def berkowitz_charpoly(self, x=Dummy('lambda'), simplify=_utilities_simplify):
return self.charpoly(x=x)
def berkowitz_det(self):
"""Computes determinant using Berkowitz method.
See Also
========
det
"""
return self.det(method='berkowitz')
def berkowitz_eigenvals(self, **flags):
"""Computes eigenvalues of a Matrix using Berkowitz method."""
return self.eigenvals(**flags)
def berkowitz_minors(self):
"""Computes principal minors using Berkowitz method."""
sign, minors = self.one, []
for poly in self.berkowitz():
minors.append(sign * poly[-1])
sign = -sign
return tuple(minors)
def berkowitz(self):
from sympy.matrices import zeros
berk = ((1,),)
if not self:
return berk
if not self.is_square:
raise NonSquareMatrixError()
A, N = self, self.rows
transforms = [0] * (N - 1)
for n in range(N, 1, -1):
T, k = zeros(n + 1, n), n - 1
R, C = -A[k, :k], A[:k, k]
A, a = A[:k, :k], -A[k, k]
items = [C]
for i in range(0, n - 2):
items.append(A * items[i])
for i, B in enumerate(items):
items[i] = (R * B)[0, 0]
items = [self.one, a] + items
for i in range(n):
T[i:, i] = items[:n - i + 1]
transforms[k - 1] = T
polys = [self._new([self.one, -A[0, 0]])]
for i, T in enumerate(transforms):
polys.append(T * polys[i])
return berk + tuple(map(tuple, polys))
def cofactorMatrix(self, method="berkowitz"):
return self.cofactor_matrix(method=method)
def det_bareis(self):
return _det_bareiss(self)
def det_LU_decomposition(self):
"""Compute matrix determinant using LU decomposition.
Note that this method fails if the LU decomposition itself
fails. In particular, if the matrix has no inverse this method
will fail.
TODO: Implement algorithm for sparse matrices (SFF),
http://www.eecis.udel.edu/~saunders/papers/sffge/it5.ps.
See Also
========
det
berkowitz_det
"""
return self.det(method='lu')
def jordan_cell(self, eigenval, n):
return self.jordan_block(size=n, eigenvalue=eigenval)
def jordan_cells(self, calc_transformation=True):
P, J = self.jordan_form()
return P, J.get_diag_blocks()
def minorEntry(self, i, j, method="berkowitz"):
return self.minor(i, j, method=method)
def minorMatrix(self, i, j):
return self.minor_submatrix(i, j)
def permuteBkwd(self, perm):
"""Permute the rows of the matrix with the given permutation in reverse."""
return self.permute_rows(perm, direction='backward')
def permuteFwd(self, perm):
"""Permute the rows of the matrix with the given permutation."""
return self.permute_rows(perm, direction='forward')
@property
def kind(self) -> MatrixKind:
elem_kinds = {e.kind for e in self.flat()}
if len(elem_kinds) == 1:
elemkind, = elem_kinds
else:
elemkind = UndefinedKind
return MatrixKind(elemkind)
def flat(self):
"""
Returns a flat list of all elements in the matrix.
Examples
========
>>> from sympy import Matrix
>>> m = Matrix([[0, 2], [3, 4]])
>>> m.flat()
[0, 2, 3, 4]
See Also
========
tolist
values
"""
return [self[i, j] for i in range(self.rows) for j in range(self.cols)]
def __array__(self, dtype=object, copy=None):
if copy is not None and not copy:
raise TypeError("Cannot implement copy=False when converting Matrix to ndarray")
from .dense import matrix2numpy
return matrix2numpy(self, dtype=dtype)
def __len__(self):
"""Return the number of elements of ``self``.
Implemented mainly so bool(Matrix()) == False.
"""
return self.rows * self.cols
def _matrix_pow_by_jordan_blocks(self, num):
from sympy.matrices import diag, MutableMatrix
def jordan_cell_power(jc, n):
N = jc.shape[0]
l = jc[0,0]
if l.is_zero:
if N == 1 and n.is_nonnegative:
jc[0,0] = l**n
elif not (n.is_integer and n.is_nonnegative):
raise NonInvertibleMatrixError("Non-invertible matrix can only be raised to a nonnegative integer")
else:
for i in range(N):
jc[0,i] = KroneckerDelta(i, n)
else:
for i in range(N):
bn = binomial(n, i)
if isinstance(bn, binomial):
bn = bn._eval_expand_func()
jc[0,i] = l**(n-i)*bn
for i in range(N):
for j in range(1, N-i):
jc[j,i+j] = jc [j-1,i+j-1]
P, J = self.jordan_form()
jordan_cells = J.get_diag_blocks()
# Make sure jordan_cells matrices are mutable:
jordan_cells = [MutableMatrix(j) for j in jordan_cells]
for j in jordan_cells:
jordan_cell_power(j, num)
return self._new(P.multiply(diag(*jordan_cells))
.multiply(P.inv()))
def __str__(self):
if S.Zero in self.shape:
return 'Matrix(%s, %s, [])' % (self.rows, self.cols)
return "Matrix(%s)" % str(self.tolist())
def _format_str(self, printer=None):
if not printer:
printer = StrPrinter()
# Handle zero dimensions:
if S.Zero in self.shape:
return 'Matrix(%s, %s, [])' % (self.rows, self.cols)
if self.rows == 1:
return "Matrix([%s])" % self.table(printer, rowsep=',\n')
return "Matrix([\n%s])" % self.table(printer, rowsep=',\n')
@classmethod
def irregular(cls, ntop, *matrices, **kwargs):
"""Return a matrix filled by the given matrices which
are listed in order of appearance from left to right, top to
bottom as they first appear in the matrix. They must fill the
matrix completely.
Examples
========
>>> from sympy import ones, Matrix
>>> Matrix.irregular(3, ones(2,1), ones(3,3)*2, ones(2,2)*3,
... ones(1,1)*4, ones(2,2)*5, ones(1,2)*6, ones(1,2)*7)
Matrix([
[1, 2, 2, 2, 3, 3],
[1, 2, 2, 2, 3, 3],
[4, 2, 2, 2, 5, 5],
[6, 6, 7, 7, 5, 5]])
"""
ntop = as_int(ntop)
# make sure we are working with explicit matrices
b = [i.as_explicit() if hasattr(i, 'as_explicit') else i
for i in matrices]
q = list(range(len(b)))
dat = [i.rows for i in b]
active = [q.pop(0) for _ in range(ntop)]
cols = sum(b[i].cols for i in active)
rows = []
while any(dat):
r = []
for a, j in enumerate(active):
r.extend(b[j][-dat[j], :])
dat[j] -= 1
if dat[j] == 0 and q:
active[a] = q.pop(0)
if len(r) != cols:
raise ValueError(filldedent('''
Matrices provided do not appear to fill
the space completely.'''))
rows.append(r)
return cls._new(rows)
@classmethod
def _handle_ndarray(cls, arg):
# NumPy array or matrix or some other object that implements
# __array__. So let's first use this method to get a
# numpy.array() and then make a Python list out of it.
arr = arg.__array__()
if len(arr.shape) == 2:
rows, cols = arr.shape[0], arr.shape[1]
flat_list = [cls._sympify(i) for i in arr.ravel()]
return rows, cols, flat_list
elif len(arr.shape) == 1:
flat_list = [cls._sympify(i) for i in arr]
return arr.shape[0], 1, flat_list
else:
raise NotImplementedError(
"SymPy supports just 1D and 2D matrices")
@classmethod
def _handle_creation_inputs(cls, *args, **kwargs):
"""Return the number of rows, cols and flat matrix elements.
Examples
========
>>> from sympy import Matrix, I
Matrix can be constructed as follows:
* from a nested list of iterables
>>> Matrix( ((1, 2+I), (3, 4)) )
Matrix([
[1, 2 + I],
[3, 4]])
* from un-nested iterable (interpreted as a column)
>>> Matrix( [1, 2] )
Matrix([
[1],
[2]])
* from un-nested iterable with dimensions
>>> Matrix(1, 2, [1, 2] )
Matrix([[1, 2]])
* from no arguments (a 0 x 0 matrix)
>>> Matrix()
Matrix(0, 0, [])
* from a rule
>>> Matrix(2, 2, lambda i, j: i/(j + 1) )
Matrix([
[0, 0],
[1, 1/2]])
See Also
========
irregular - filling a matrix with irregular blocks
"""
from sympy.matrices import SparseMatrix
from sympy.matrices.expressions.matexpr import MatrixSymbol
from sympy.matrices.expressions.blockmatrix import BlockMatrix
flat_list = None
if len(args) == 1:
# Matrix(SparseMatrix(...))
if isinstance(args[0], SparseMatrix):
return args[0].rows, args[0].cols, flatten(args[0].tolist())
# Matrix(Matrix(...))
elif isinstance(args[0], MatrixBase):
return args[0].rows, args[0].cols, args[0].flat()
# Matrix(MatrixSymbol('X', 2, 2))
elif isinstance(args[0], Basic) and args[0].is_Matrix:
return args[0].rows, args[0].cols, args[0].as_explicit().flat()
elif isinstance(args[0], mp.matrix):
M = args[0]
flat_list = [cls._sympify(x) for x in M]
return M.rows, M.cols, flat_list
# Matrix(numpy.ones((2, 2)))
elif hasattr(args[0], "__array__"):
return cls._handle_ndarray(args[0])
# Matrix([1, 2, 3]) or Matrix([[1, 2], [3, 4]])
elif is_sequence(args[0]) \
and not isinstance(args[0], DeferredVector):
dat = list(args[0])
ismat = lambda i: isinstance(i, MatrixBase) and (
evaluate or isinstance(i, (BlockMatrix, MatrixSymbol)))
raw = lambda i: is_sequence(i) and not ismat(i)
evaluate = kwargs.get('evaluate', True)
if evaluate:
def make_explicit(x):
"""make Block and Symbol explicit"""
if isinstance(x, BlockMatrix):
return x.as_explicit()
elif isinstance(x, MatrixSymbol) and all(_.is_Integer for _ in x.shape):
return x.as_explicit()
else:
return x
def make_explicit_row(row):
# Could be list or could be list of lists
if isinstance(row, (list, tuple)):
return [make_explicit(x) for x in row]
else:
return make_explicit(row)
if isinstance(dat, (list, tuple)):
dat = [make_explicit_row(row) for row in dat]
if len(dat) == 0:
rows = cols = 0
flat_list = []
elif all(raw(i) for i in dat) and len(dat[0]) == 0:
if not all(len(i) == 0 for i in dat):
raise ValueError('mismatched dimensions')
rows = len(dat)
cols = 0
flat_list = []
elif not any(raw(i) or ismat(i) for i in dat):
# a column as a list of values
flat_list = [cls._sympify(i) for i in dat]
rows = len(flat_list)
cols = 1 if rows else 0
elif evaluate and all(ismat(i) for i in dat):
# a column as a list of matrices
ncol = {i.cols for i in dat if any(i.shape)}
if ncol:
if len(ncol) != 1:
raise ValueError('mismatched dimensions')
flat_list = [_ for i in dat for r in i.tolist() for _ in r]
cols = ncol.pop()
rows = len(flat_list)//cols
else:
rows = cols = 0
flat_list = []
elif evaluate and any(ismat(i) for i in dat):
ncol = set()
flat_list = []
for i in dat:
if ismat(i):
flat_list.extend(
[k for j in i.tolist() for k in j])
if any(i.shape):
ncol.add(i.cols)
elif raw(i):
if i:
ncol.add(len(i))
flat_list.extend([cls._sympify(ij) for ij in i])
else:
ncol.add(1)
flat_list.append(i)
if len(ncol) > 1:
raise ValueError('mismatched dimensions')
cols = ncol.pop()
rows = len(flat_list)//cols
else:
# list of lists; each sublist is a logical row
# which might consist of many rows if the values in
# the row are matrices
flat_list = []
ncol = set()
rows = cols = 0
for row in dat:
if not is_sequence(row) and \
not getattr(row, 'is_Matrix', False):
raise ValueError('expecting list of lists')
if hasattr(row, '__array__'):
if 0 in row.shape:
continue
if evaluate and all(ismat(i) for i in row):
r, c, flatT = cls._handle_creation_inputs(
[i.T for i in row])
T = reshape(flatT, [c])
flat = \
[T[i][j] for j in range(c) for i in range(r)]
r, c = c, r
else:
r = 1
if getattr(row, 'is_Matrix', False):
c = 1
flat = [row]
else:
c = len(row)
flat = [cls._sympify(i) for i in row]
ncol.add(c)
if len(ncol) > 1:
raise ValueError('mismatched dimensions')
flat_list.extend(flat)
rows += r
cols = ncol.pop() if ncol else 0
elif len(args) == 3:
rows = as_int(args[0])
cols = as_int(args[1])
if rows < 0 or cols < 0:
raise ValueError("Cannot create a {} x {} matrix. "
"Both dimensions must be positive".format(rows, cols))
# Matrix(2, 2, lambda i, j: i+j)
if len(args) == 3 and isinstance(args[2], Callable):
op = args[2]
flat_list = []
for i in range(rows):
flat_list.extend(
[cls._sympify(op(cls._sympify(i), cls._sympify(j)))
for j in range(cols)])
# Matrix(2, 2, [1, 2, 3, 4])
elif len(args) == 3 and is_sequence(args[2]):
flat_list = args[2]
if len(flat_list) != rows * cols:
raise ValueError(
'List length should be equal to rows*columns')
flat_list = [cls._sympify(i) for i in flat_list]
# Matrix()
elif len(args) == 0:
# Empty Matrix
rows = cols = 0
flat_list = []
if flat_list is None:
raise TypeError(filldedent('''
Data type not understood; expecting list of lists
or lists of values.'''))
return rows, cols, flat_list
def _setitem(self, key, value):
"""Helper to set value at location given by key.
Examples
========
>>> from sympy import Matrix, I, zeros, ones
>>> m = Matrix(((1, 2+I), (3, 4)))
>>> m
Matrix([
[1, 2 + I],
[3, 4]])
>>> m[1, 0] = 9
>>> m
Matrix([
[1, 2 + I],
[9, 4]])
>>> m[1, 0] = [[0, 1]]
To replace row r you assign to position r*m where m
is the number of columns:
>>> M = zeros(4)
>>> m = M.cols
>>> M[3*m] = ones(1, m)*2; M
Matrix([
[0, 0, 0, 0],
[0, 0, 0, 0],
[0, 0, 0, 0],
[2, 2, 2, 2]])
And to replace column c you can assign to position c:
>>> M[2] = ones(m, 1)*4; M
Matrix([
[0, 0, 4, 0],
[0, 0, 4, 0],
[0, 0, 4, 0],
[2, 2, 4, 2]])
"""
from .dense import Matrix
is_slice = isinstance(key, slice)
i, j = key = self.key2ij(key)
is_mat = isinstance(value, MatrixBase)
if isinstance(i, slice) or isinstance(j, slice):
if is_mat:
self.copyin_matrix(key, value)
return
if not isinstance(value, Expr) and is_sequence(value):
self.copyin_list(key, value)
return
raise ValueError('unexpected value: %s' % value)
else:
if (not is_mat and
not isinstance(value, Basic) and is_sequence(value)):
value = Matrix(value)
is_mat = True
if is_mat:
if is_slice:
key = (slice(*divmod(i, self.cols)),
slice(*divmod(j, self.cols)))
else:
key = (slice(i, i + value.rows),
slice(j, j + value.cols))
self.copyin_matrix(key, value)
else:
return i, j, self._sympify(value)
return
def add(self, b):
"""Return self + b."""
return self + b
def condition_number(self):
"""Returns the condition number of a matrix.
This is the maximum singular value divided by the minimum singular value
Examples
========
>>> from sympy import Matrix, S
>>> A = Matrix([[1, 0, 0], [0, 10, 0], [0, 0, S.One/10]])
>>> A.condition_number()
100
See Also
========
singular_values
"""
if not self:
return self.zero
singularvalues = self.singular_values()
return Max(*singularvalues) / Min(*singularvalues)
def copy(self):
"""
Returns the copy of a matrix.
Examples
========
>>> from sympy import Matrix
>>> A = Matrix(2, 2, [1, 2, 3, 4])
>>> A.copy()
Matrix([
[1, 2],
[3, 4]])
"""
return self._new(self.rows, self.cols, self.flat())
def cross(self, b):
r"""
Return the cross product of ``self`` and ``b`` relaxing the condition
of compatible dimensions: if each has 3 elements, a matrix of the
same type and shape as ``self`` will be returned. If ``b`` has the same
shape as ``self`` then common identities for the cross product (like
`a \times b = - b \times a`) will hold.
Parameters
==========
b : 3x1 or 1x3 Matrix
See Also
========
dot
hat
vee
multiply
multiply_elementwise
"""
from sympy.matrices.expressions.matexpr import MatrixExpr
if not isinstance(b, (MatrixBase, MatrixExpr)):
raise TypeError(
"{} must be a Matrix, not {}.".format(b, type(b)))
if not (self.rows * self.cols == b.rows * b.cols == 3):
raise ShapeError("Dimensions incorrect for cross product: %s x %s" %
((self.rows, self.cols), (b.rows, b.cols)))
else:
return self._new(self.rows, self.cols, (
(self[1] * b[2] - self[2] * b[1]),
(self[2] * b[0] - self[0] * b[2]),
(self[0] * b[1] - self[1] * b[0])))
def hat(self):
r"""
Return the skew-symmetric matrix representing the cross product,
so that ``self.hat() * b`` is equivalent to ``self.cross(b)``.
Examples
========
Calling ``hat`` creates a skew-symmetric 3x3 Matrix from a 3x1 Matrix:
>>> from sympy import Matrix
>>> a = Matrix([1, 2, 3])
>>> a.hat()
Matrix([
[ 0, -3, 2],
[ 3, 0, -1],
[-2, 1, 0]])
Multiplying it with another 3x1 Matrix calculates the cross product:
>>> b = Matrix([3, 2, 1])
>>> a.hat() * b
Matrix([
[-4],
[ 8],
[-4]])
Which is equivalent to calling the ``cross`` method:
>>> a.cross(b)
Matrix([
[-4],
[ 8],
[-4]])
See Also
========
dot
cross
vee
multiply
multiply_elementwise
"""
if self.shape != (3, 1):
raise ShapeError("Dimensions incorrect, expected (3, 1), got " +
str(self.shape))
else:
x, y, z = self
return self._new(3, 3, (
0, -z, y,
z, 0, -x,
-y, x, 0))
def vee(self):
r"""
Return a 3x1 vector from a skew-symmetric matrix representing the cross product,
so that ``self * b`` is equivalent to ``self.vee().cross(b)``.
Examples
========
Calling ``vee`` creates a vector from a skew-symmetric Matrix:
>>> from sympy import Matrix
>>> A = Matrix([[0, -3, 2], [3, 0, -1], [-2, 1, 0]])
>>> a = A.vee()
>>> a
Matrix([
[1],
[2],
[3]])
Calculating the matrix product of the original matrix with a vector
is equivalent to a cross product:
>>> b = Matrix([3, 2, 1])
>>> A * b
Matrix([
[-4],
[ 8],
[-4]])
>>> a.cross(b)
Matrix([
[-4],
[ 8],
[-4]])
``vee`` can also be used to retrieve angular velocity expressions.
Defining a rotation matrix:
>>> from sympy import rot_ccw_axis3, trigsimp
>>> from sympy.physics.mechanics import dynamicsymbols
>>> theta = dynamicsymbols('theta')
>>> R = rot_ccw_axis3(theta)
>>> R
Matrix([
[cos(theta(t)), -sin(theta(t)), 0],
[sin(theta(t)), cos(theta(t)), 0],
[ 0, 0, 1]])
We can retrive the angular velocity:
>>> Omega = R.T * R.diff()
>>> Omega = trigsimp(Omega)
>>> Omega.vee()
Matrix([
[ 0],
[ 0],
[Derivative(theta(t), t)]])
See Also
========
dot
cross
hat
multiply
multiply_elementwise
"""
if self.shape != (3, 3):
raise ShapeError("Dimensions incorrect, expected (3, 3), got " +
str(self.shape))
elif not self.is_anti_symmetric():
raise ValueError("Matrix is not skew-symmetric")
else:
return self._new(3, 1, (
self[2, 1],
self[0, 2],
self[1, 0]))
@property
def D(self):
"""Return Dirac conjugate (if ``self.rows == 4``).
Examples
========
>>> from sympy import Matrix, I, eye
>>> m = Matrix((0, 1 + I, 2, 3))
>>> m.D
Matrix([[0, 1 - I, -2, -3]])
>>> m = (eye(4) + I*eye(4))
>>> m[0, 3] = 2
>>> m.D
Matrix([
[1 - I, 0, 0, 0],
[ 0, 1 - I, 0, 0],
[ 0, 0, -1 + I, 0],
[ 2, 0, 0, -1 + I]])
If the matrix does not have 4 rows an AttributeError will be raised
because this property is only defined for matrices with 4 rows.
>>> Matrix(eye(2)).D
Traceback (most recent call last):
...
AttributeError: Matrix has no attribute D.
See Also
========
sympy.matrices.matrixbase.MatrixBase.conjugate: By-element conjugation
sympy.matrices.matrixbase.MatrixBase.H: Hermite conjugation
"""
from sympy.physics.matrices import mgamma
if self.rows != 4:
# In Python 3.2, properties can only return an AttributeError
# so we can't raise a ShapeError -- see commit which added the
# first line of this inline comment. Also, there is no need
# for a message since MatrixBase will raise the AttributeError
raise AttributeError
return self.H * mgamma(0)
def dot(self, b, hermitian=None, conjugate_convention=None):
"""Return the dot or inner product of two vectors of equal length.
Here ``self`` must be a ``Matrix`` of size 1 x n or n x 1, and ``b``
must be either a matrix of size 1 x n, n x 1, or a list/tuple of length n.
A scalar is returned.
By default, ``dot`` does not conjugate ``self`` or ``b``, even if there are
complex entries. Set ``hermitian=True`` (and optionally a ``conjugate_convention``)
to compute the hermitian inner product.
Possible kwargs are ``hermitian`` and ``conjugate_convention``.
If ``conjugate_convention`` is ``"left"``, ``"math"`` or ``"maths"``,
the conjugate of the first vector (``self``) is used. If ``"right"``
or ``"physics"`` is specified, the conjugate of the second vector ``b`` is used.
Examples
========
>>> from sympy import Matrix
>>> M = Matrix([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
>>> v = Matrix([1, 1, 1])
>>> M.row(0).dot(v)
6
>>> M.col(0).dot(v)
12
>>> v = [3, 2, 1]
>>> M.row(0).dot(v)
10
>>> from sympy import I
>>> q = Matrix([1*I, 1*I, 1*I])
>>> q.dot(q, hermitian=False)
-3
>>> q.dot(q, hermitian=True)
3
>>> q1 = Matrix([1, 1, 1*I])
>>> q.dot(q1, hermitian=True, conjugate_convention="maths")
1 - 2*I
>>> q.dot(q1, hermitian=True, conjugate_convention="physics")
1 + 2*I
See Also
========
cross
multiply
multiply_elementwise
"""
from .dense import Matrix
if not isinstance(b, MatrixBase):
if is_sequence(b):
if len(b) != self.cols and len(b) != self.rows:
raise ShapeError(
"Dimensions incorrect for dot product: %s, %s" % (
self.shape, len(b)))
return self.dot(Matrix(b))
else:
raise TypeError(
"`b` must be an ordered iterable or Matrix, not %s." %
type(b))
if (1 not in self.shape) or (1 not in b.shape):
raise ShapeError
if len(self) != len(b):
raise ShapeError(
"Dimensions incorrect for dot product: %s, %s" % (self.shape, b.shape))
mat = self
n = len(mat)
if mat.shape != (1, n):
mat = mat.reshape(1, n)
if b.shape != (n, 1):
b = b.reshape(n, 1)
# Now ``mat`` is a row vector and ``b`` is a column vector.
# If it so happens that only conjugate_convention is passed
# then automatically set hermitian to True. If only hermitian
# is true but no conjugate_convention is not passed then
# automatically set it to ``"maths"``
if conjugate_convention is not None and hermitian is None:
hermitian = True
if hermitian and conjugate_convention is None:
conjugate_convention = "maths"
if hermitian == True:
if conjugate_convention in ("maths", "left", "math"):
mat = mat.conjugate()
elif conjugate_convention in ("physics", "right"):
b = b.conjugate()
else:
raise ValueError("Unknown conjugate_convention was entered."
" conjugate_convention must be one of the"
" following: math, maths, left, physics or right.")
return (mat * b)[0]
def dual(self):
"""Returns the dual of a matrix.
A dual of a matrix is:
``(1/2)*levicivita(i, j, k, l)*M(k, l)`` summed over indices `k` and `l`
Since the levicivita method is anti_symmetric for any pairwise
exchange of indices, the dual of a symmetric matrix is the zero
matrix. Strictly speaking the dual defined here assumes that the
'matrix' `M` is a contravariant anti_symmetric second rank tensor,
so that the dual is a covariant second rank tensor.
"""
from sympy.matrices import zeros
M, n = self[:, :], self.rows
work = zeros(n)
if self.is_symmetric():
return work
for i in range(1, n):
for j in range(1, n):
acum = 0
for k in range(1, n):
acum += LeviCivita(i, j, 0, k) * M[0, k]
work[i, j] = acum
work[j, i] = -acum
for l in range(1, n):
acum = 0
for a in range(1, n):
for b in range(1, n):
acum += LeviCivita(0, l, a, b) * M[a, b]
acum /= 2
work[0, l] = -acum
work[l, 0] = acum
return work
def _eval_matrix_exp_jblock(self):
"""A helper function to compute an exponential of a Jordan block
matrix
Examples
========
>>> from sympy import Symbol, Matrix
>>> l = Symbol('lamda')
A trivial example of 1*1 Jordan block:
>>> m = Matrix.jordan_block(1, l)
>>> m._eval_matrix_exp_jblock()
Matrix([[exp(lamda)]])
An example of 3*3 Jordan block:
>>> m = Matrix.jordan_block(3, l)
>>> m._eval_matrix_exp_jblock()
Matrix([
[exp(lamda), exp(lamda), exp(lamda)/2],
[ 0, exp(lamda), exp(lamda)],
[ 0, 0, exp(lamda)]])
References
==========
.. [1] https://en.wikipedia.org/wiki/Matrix_function#Jordan_decomposition
"""
size = self.rows
l = self[0, 0]
exp_l = exp(l)
bands = {i: exp_l / factorial(i) for i in range(size)}
from .sparsetools import banded
return self.__class__(banded(size, bands))
def analytic_func(self, f, x):
"""
Computes f(A) where A is a Square Matrix
and f is an analytic function.
Examples
========
>>> from sympy import Symbol, Matrix, S, log
>>> x = Symbol('x')
>>> m = Matrix([[S(5)/4, S(3)/4], [S(3)/4, S(5)/4]])
>>> f = log(x)
>>> m.analytic_func(f, x)
Matrix([
[ 0, log(2)],
[log(2), 0]])
Parameters
==========
f : Expr
Analytic Function
x : Symbol
parameter of f
"""
f, x = _sympify(f), _sympify(x)
if not self.is_square:
raise NonSquareMatrixError
if not x.is_symbol:
raise ValueError("{} must be a symbol.".format(x))
if x not in f.free_symbols:
raise ValueError(
"{} must be a parameter of {}.".format(x, f))
if x in self.free_symbols:
raise ValueError(
"{} must not be a parameter of {}.".format(x, self))
eigen = self.eigenvals()
max_mul = max(eigen.values())
derivative = {}
dd = f
for i in range(max_mul - 1):
dd = diff(dd, x)
derivative[i + 1] = dd
n = self.shape[0]
r = self.zeros(n)
f_val = self.zeros(n, 1)
row = 0
for i in eigen:
mul = eigen[i]
f_val[row] = f.subs(x, i)
if f_val[row].is_number and not f_val[row].is_complex:
raise ValueError(
"Cannot evaluate the function because the "
"function {} is not analytic at the given "
"eigenvalue {}".format(f, f_val[row]))
val = 1
for a in range(n):
r[row, a] = val
val *= i
if mul > 1:
coe = [1 for ii in range(n)]
deri = 1
while mul > 1:
row = row + 1
mul -= 1
d_i = derivative[deri].subs(x, i)
if d_i.is_number and not d_i.is_complex:
raise ValueError(
"Cannot evaluate the function because the "
"derivative {} is not analytic at the given "
"eigenvalue {}".format(derivative[deri], d_i))
f_val[row] = d_i
for a in range(n):
if a - deri + 1 <= 0:
r[row, a] = 0
coe[a] = 0
continue
coe[a] = coe[a]*(a - deri + 1)
r[row, a] = coe[a]*pow(i, a - deri)
deri += 1
row += 1
c = r.solve(f_val)
ans = self.zeros(n)
pre = self.eye(n)
for i in range(n):
ans = ans + c[i]*pre
pre *= self
return ans
def exp(self):
"""Return the exponential of a square matrix.
Examples
========
>>> from sympy import Symbol, Matrix
>>> t = Symbol('t')
>>> m = Matrix([[0, 1], [-1, 0]]) * t
>>> m.exp()
Matrix([
[ exp(I*t)/2 + exp(-I*t)/2, -I*exp(I*t)/2 + I*exp(-I*t)/2],
[I*exp(I*t)/2 - I*exp(-I*t)/2, exp(I*t)/2 + exp(-I*t)/2]])
"""
if not self.is_square:
raise NonSquareMatrixError(
"Exponentiation is valid only for square matrices")
try:
P, J = self.jordan_form()
cells = J.get_diag_blocks()
except MatrixError:
raise NotImplementedError(
"Exponentiation is implemented only for matrices for which the Jordan normal form can be computed")
blocks = [cell._eval_matrix_exp_jblock() for cell in cells]
from sympy.matrices import diag
eJ = diag(*blocks)
# n = self.rows
ret = P.multiply(eJ, dotprodsimp=None).multiply(P.inv(), dotprodsimp=None)
if all(value.is_real for value in self.values()):
return type(self)(re(ret))
else:
return type(self)(ret)
def _eval_matrix_log_jblock(self):
"""Helper function to compute logarithm of a jordan block.
Examples
========
>>> from sympy import Symbol, Matrix
>>> l = Symbol('lamda')
A trivial example of 1*1 Jordan block:
>>> m = Matrix.jordan_block(1, l)
>>> m._eval_matrix_log_jblock()
Matrix([[log(lamda)]])
An example of 3*3 Jordan block:
>>> m = Matrix.jordan_block(3, l)
>>> m._eval_matrix_log_jblock()
Matrix([
[log(lamda), 1/lamda, -1/(2*lamda**2)],
[ 0, log(lamda), 1/lamda],
[ 0, 0, log(lamda)]])
"""
size = self.rows
l = self[0, 0]
if l.is_zero:
raise MatrixError(
'Could not take logarithm or reciprocal for the given '
'eigenvalue {}'.format(l))
bands = {0: log(l)}
for i in range(1, size):
bands[i] = -((-l) ** -i) / i
from .sparsetools import banded
return self.__class__(banded(size, bands))
def log(self, simplify=cancel):
"""Return the logarithm of a square matrix.
Parameters
==========
simplify : function, bool
The function to simplify the result with.
Default is ``cancel``, which is effective to reduce the
expression growing for taking reciprocals and inverses for
symbolic matrices.
Examples
========
>>> from sympy import S, Matrix
Examples for positive-definite matrices:
>>> m = Matrix([[1, 1], [0, 1]])
>>> m.log()
Matrix([
[0, 1],
[0, 0]])
>>> m = Matrix([[S(5)/4, S(3)/4], [S(3)/4, S(5)/4]])
>>> m.log()
Matrix([
[ 0, log(2)],
[log(2), 0]])
Examples for non positive-definite matrices:
>>> m = Matrix([[S(3)/4, S(5)/4], [S(5)/4, S(3)/4]])
>>> m.log()
Matrix([
[ I*pi/2, log(2) - I*pi/2],
[log(2) - I*pi/2, I*pi/2]])
>>> m = Matrix(
... [[0, 0, 0, 1],
... [0, 0, 1, 0],
... [0, 1, 0, 0],
... [1, 0, 0, 0]])
>>> m.log()
Matrix([
[ I*pi/2, 0, 0, -I*pi/2],
[ 0, I*pi/2, -I*pi/2, 0],
[ 0, -I*pi/2, I*pi/2, 0],
[-I*pi/2, 0, 0, I*pi/2]])
"""
if not self.is_square:
raise NonSquareMatrixError(
"Logarithm is valid only for square matrices")
try:
if simplify:
P, J = simplify(self).jordan_form()
else:
P, J = self.jordan_form()
cells = J.get_diag_blocks()
except MatrixError:
raise NotImplementedError(
"Logarithm is implemented only for matrices for which "
"the Jordan normal form can be computed")
blocks = [
cell._eval_matrix_log_jblock()
for cell in cells]
from sympy.matrices import diag
eJ = diag(*blocks)
if simplify:
ret = simplify(P * eJ * simplify(P.inv()))
ret = self.__class__(ret)
else:
ret = P * eJ * P.inv()
return ret
def is_nilpotent(self):
"""Checks if a matrix is nilpotent.
A matrix B is nilpotent if for some integer k, B**k is
a zero matrix.
Examples
========
>>> from sympy import Matrix
>>> a = Matrix([[0, 0, 0], [1, 0, 0], [1, 1, 0]])
>>> a.is_nilpotent()
True
>>> a = Matrix([[1, 0, 1], [1, 0, 0], [1, 1, 0]])
>>> a.is_nilpotent()
False
"""
if not self:
return True
if not self.is_square:
raise NonSquareMatrixError(
"Nilpotency is valid only for square matrices")
x = uniquely_named_symbol('x', self, modify=lambda s: '_' + s)
p = self.charpoly(x)
if p.args[0] == x ** self.rows:
return True
return False
def key2bounds(self, keys):
"""Converts a key with potentially mixed types of keys (integer and slice)
into a tuple of ranges and raises an error if any index is out of ``self``'s
range.
See Also
========
key2ij
"""
islice, jslice = [isinstance(k, slice) for k in keys]
if islice:
if not self.rows:
rlo = rhi = 0
else:
rlo, rhi = keys[0].indices(self.rows)[:2]
else:
rlo = a2idx(keys[0], self.rows)
rhi = rlo + 1
if jslice:
if not self.cols:
clo = chi = 0
else:
clo, chi = keys[1].indices(self.cols)[:2]
else:
clo = a2idx(keys[1], self.cols)
chi = clo + 1
return rlo, rhi, clo, chi
def key2ij(self, key):
"""Converts key into canonical form, converting integers or indexable
items into valid integers for ``self``'s range or returning slices
unchanged.
See Also
========
key2bounds
"""
if is_sequence(key):
if not len(key) == 2:
raise TypeError('key must be a sequence of length 2')
return [a2idx(i, n) if not isinstance(i, slice) else i
for i, n in zip(key, self.shape)]
elif isinstance(key, slice):
return key.indices(len(self))[:2]
else:
return divmod(a2idx(key, len(self)), self.cols)
def normalized(self, iszerofunc=_iszero):
"""Return the normalized version of ``self``.
Parameters
==========
iszerofunc : Function, optional
A function to determine whether ``self`` is a zero vector.
The default ``_iszero`` tests to see if each element is
exactly zero.
Returns
=======
Matrix
Normalized vector form of ``self``.
It has the same length as a unit vector. However, a zero vector
will be returned for a vector with norm 0.
Raises
======
ShapeError
If the matrix is not in a vector form.
See Also
========
norm
"""
if self.rows != 1 and self.cols != 1:
raise ShapeError("A Matrix must be a vector to normalize.")
norm = self.norm()
if iszerofunc(norm):
out = self.zeros(self.rows, self.cols)
else:
out = self.applyfunc(lambda i: i / norm)
return out
def norm(self, ord=None):
"""Return the Norm of a Matrix or Vector.
In the simplest case this is the geometric size of the vector
Other norms can be specified by the ord parameter
===== ============================ ==========================
ord norm for matrices norm for vectors
===== ============================ ==========================
None Frobenius norm 2-norm
'fro' Frobenius norm - does not exist
inf maximum row sum max(abs(x))
-inf -- min(abs(x))
1 maximum column sum as below
-1 -- as below
2 2-norm (largest sing. value) as below
-2 smallest singular value as below
other - does not exist sum(abs(x)**ord)**(1./ord)
===== ============================ ==========================
Examples
========
>>> from sympy import Matrix, Symbol, trigsimp, cos, sin, oo
>>> x = Symbol('x', real=True)
>>> v = Matrix([cos(x), sin(x)])
>>> trigsimp( v.norm() )
1
>>> v.norm(10)
(sin(x)**10 + cos(x)**10)**(1/10)
>>> A = Matrix([[1, 1], [1, 1]])
>>> A.norm(1) # maximum sum of absolute values of A is 2
2
>>> A.norm(2) # Spectral norm (max of |Ax|/|x| under 2-vector-norm)
2
>>> A.norm(-2) # Inverse spectral norm (smallest singular value)
0
>>> A.norm() # Frobenius Norm
2
>>> A.norm(oo) # Infinity Norm
2
>>> Matrix([1, -2]).norm(oo)
2
>>> Matrix([-1, 2]).norm(-oo)
1
See Also
========
normalized
"""
# Row or Column Vector Norms
vals = list(self.values()) or [0]
if S.One in self.shape:
if ord in (2, None): # Common case sqrt(<x, x>)
return sqrt(Add(*(abs(i) ** 2 for i in vals)))
elif ord == 1: # sum(abs(x))
return Add(*(abs(i) for i in vals))
elif ord is S.Infinity: # max(abs(x))
return Max(*[abs(i) for i in vals])
elif ord is S.NegativeInfinity: # min(abs(x))
return Min(*[abs(i) for i in vals])
# Otherwise generalize the 2-norm, Sum(x_i**ord)**(1/ord)
# Note that while useful this is not mathematically a norm
try:
return Pow(Add(*(abs(i) ** ord for i in vals)), S.One / ord)
except (NotImplementedError, TypeError):
raise ValueError("Expected order to be Number, Symbol, oo")
# Matrix Norms
else:
if ord == 1: # Maximum column sum
m = self.applyfunc(abs)
return Max(*[sum(m.col(i)) for i in range(m.cols)])
elif ord == 2: # Spectral Norm
# Maximum singular value
return Max(*self.singular_values())
elif ord == -2:
# Minimum singular value
return Min(*self.singular_values())
elif ord is S.Infinity: # Infinity Norm - Maximum row sum
m = self.applyfunc(abs)
return Max(*[sum(m.row(i)) for i in range(m.rows)])
elif (ord is None or isinstance(ord,
str) and ord.lower() in
['f', 'fro', 'frobenius', 'vector']):
# Reshape as vector and send back to norm function
return self.vec().norm(ord=2)
else:
raise NotImplementedError("Matrix Norms under development")
def print_nonzero(self, symb="X"):
"""Shows location of non-zero entries for fast shape lookup.
Examples
========
>>> from sympy import Matrix, eye
>>> m = Matrix(2, 3, lambda i, j: i*3+j)
>>> m
Matrix([
[0, 1, 2],
[3, 4, 5]])
>>> m.print_nonzero()
[ XX]
[XXX]
>>> m = eye(4)
>>> m.print_nonzero("x")
[x ]
[ x ]
[ x ]
[ x]
"""
s = []
for i in range(self.rows):
line = []
for j in range(self.cols):
if self[i, j] == 0:
line.append(" ")
else:
line.append(str(symb))
s.append("[%s]" % ''.join(line))
print('\n'.join(s))
def project(self, v):
"""Return the projection of ``self`` onto the line containing ``v``.
Examples
========
>>> from sympy import Matrix, S, sqrt
>>> V = Matrix([sqrt(3)/2, S.Half])
>>> x = Matrix([[1, 0]])
>>> V.project(x)
Matrix([[sqrt(3)/2, 0]])
>>> V.project(-x)
Matrix([[sqrt(3)/2, 0]])
"""
return v * (self.dot(v) / v.dot(v))
def table(self, printer, rowstart='[', rowend=']', rowsep='\n',
colsep=', ', align='right'):
r"""
String form of Matrix as a table.
``printer`` is the printer to use for on the elements (generally
something like StrPrinter())
``rowstart`` is the string used to start each row (by default '[').
``rowend`` is the string used to end each row (by default ']').
``rowsep`` is the string used to separate rows (by default a newline).
``colsep`` is the string used to separate columns (by default ', ').
``align`` defines how the elements are aligned. Must be one of 'left',
'right', or 'center'. You can also use '<', '>', and '^' to mean the
same thing, respectively.
This is used by the string printer for Matrix.
Examples
========
>>> from sympy import Matrix, StrPrinter
>>> M = Matrix([[1, 2], [-33, 4]])
>>> printer = StrPrinter()
>>> M.table(printer)
'[ 1, 2]\n[-33, 4]'
>>> print(M.table(printer))
[ 1, 2]
[-33, 4]
>>> print(M.table(printer, rowsep=',\n'))
[ 1, 2],
[-33, 4]
>>> print('[%s]' % M.table(printer, rowsep=',\n'))
[[ 1, 2],
[-33, 4]]
>>> print(M.table(printer, colsep=' '))
[ 1 2]
[-33 4]
>>> print(M.table(printer, align='center'))
[ 1 , 2]
[-33, 4]
>>> print(M.table(printer, rowstart='{', rowend='}'))
{ 1, 2}
{-33, 4}
"""
# Handle zero dimensions:
if S.Zero in self.shape:
return '[]'
# Build table of string representations of the elements
res = []
# Track per-column max lengths for pretty alignment
maxlen = [0] * self.cols
for i in range(self.rows):
res.append([])
for j in range(self.cols):
s = printer._print(self[i, j])
res[-1].append(s)
maxlen[j] = max(len(s), maxlen[j])
# Patch strings together
align = {
'left': 'ljust',
'right': 'rjust',
'center': 'center',
'<': 'ljust',
'>': 'rjust',
'^': 'center',
}[align]
for i, row in enumerate(res):
for j, elem in enumerate(row):
row[j] = getattr(elem, align)(maxlen[j])
res[i] = rowstart + colsep.join(row) + rowend
return rowsep.join(res)
def rank_decomposition(self, iszerofunc=_iszero, simplify=False):
return _rank_decomposition(self, iszerofunc=iszerofunc,
simplify=simplify)
def cholesky(self, hermitian=True):
raise NotImplementedError('This function is implemented in DenseMatrix or SparseMatrix')
def LDLdecomposition(self, hermitian=True):
raise NotImplementedError('This function is implemented in DenseMatrix or SparseMatrix')
def LUdecomposition(self, iszerofunc=_iszero, simpfunc=None,
rankcheck=False):
return _LUdecomposition(self, iszerofunc=iszerofunc, simpfunc=simpfunc,
rankcheck=rankcheck)
def LUdecomposition_Simple(self, iszerofunc=_iszero, simpfunc=None,
rankcheck=False):
return _LUdecomposition_Simple(self, iszerofunc=iszerofunc,
simpfunc=simpfunc, rankcheck=rankcheck)
def LUdecompositionFF(self):
return _LUdecompositionFF(self)
def singular_value_decomposition(self):
return _singular_value_decomposition(self)
def QRdecomposition(self):
return _QRdecomposition(self)
def upper_hessenberg_decomposition(self):
return _upper_hessenberg_decomposition(self)
def diagonal_solve(self, rhs):
return _diagonal_solve(self, rhs)
def lower_triangular_solve(self, rhs):
raise NotImplementedError('This function is implemented in DenseMatrix or SparseMatrix')
def upper_triangular_solve(self, rhs):
raise NotImplementedError('This function is implemented in DenseMatrix or SparseMatrix')
def cholesky_solve(self, rhs):
return _cholesky_solve(self, rhs)
def LDLsolve(self, rhs):
return _LDLsolve(self, rhs)
def LUsolve(self, rhs, iszerofunc=_iszero):
return _LUsolve(self, rhs, iszerofunc=iszerofunc)
def QRsolve(self, b):
return _QRsolve(self, b)
def gauss_jordan_solve(self, B, freevar=False):
return _gauss_jordan_solve(self, B, freevar=freevar)
def pinv_solve(self, B, arbitrary_matrix=None):
return _pinv_solve(self, B, arbitrary_matrix=arbitrary_matrix)
def cramer_solve(self, rhs, det_method="laplace"):
return _cramer_solve(self, rhs, det_method=det_method)
def solve(self, rhs, method='GJ'):
return _solve(self, rhs, method=method)
def solve_least_squares(self, rhs, method='CH'):
return _solve_least_squares(self, rhs, method=method)
def pinv(self, method='RD'):
return _pinv(self, method=method)
def inverse_ADJ(self, iszerofunc=_iszero):
return _inv_ADJ(self, iszerofunc=iszerofunc)
def inverse_BLOCK(self, iszerofunc=_iszero):
return _inv_block(self, iszerofunc=iszerofunc)
def inverse_GE(self, iszerofunc=_iszero):
return _inv_GE(self, iszerofunc=iszerofunc)
def inverse_LU(self, iszerofunc=_iszero):
return _inv_LU(self, iszerofunc=iszerofunc)
def inverse_CH(self, iszerofunc=_iszero):
return _inv_CH(self, iszerofunc=iszerofunc)
def inverse_LDL(self, iszerofunc=_iszero):
return _inv_LDL(self, iszerofunc=iszerofunc)
def inverse_QR(self, iszerofunc=_iszero):
return _inv_QR(self, iszerofunc=iszerofunc)
def inv(self, method=None, iszerofunc=_iszero, try_block_diag=False):
return _inv(self, method=method, iszerofunc=iszerofunc,
try_block_diag=try_block_diag)
def connected_components(self):
return _connected_components(self)
def connected_components_decomposition(self):
return _connected_components_decomposition(self)
def strongly_connected_components(self):
return _strongly_connected_components(self)
def strongly_connected_components_decomposition(self, lower=True):
return _strongly_connected_components_decomposition(self, lower=lower)
_sage_ = Basic._sage_
rank_decomposition.__doc__ = _rank_decomposition.__doc__
cholesky.__doc__ = _cholesky.__doc__
LDLdecomposition.__doc__ = _LDLdecomposition.__doc__
LUdecomposition.__doc__ = _LUdecomposition.__doc__
LUdecomposition_Simple.__doc__ = _LUdecomposition_Simple.__doc__
LUdecompositionFF.__doc__ = _LUdecompositionFF.__doc__
singular_value_decomposition.__doc__ = _singular_value_decomposition.__doc__
QRdecomposition.__doc__ = _QRdecomposition.__doc__
upper_hessenberg_decomposition.__doc__ = _upper_hessenberg_decomposition.__doc__
diagonal_solve.__doc__ = _diagonal_solve.__doc__
lower_triangular_solve.__doc__ = _lower_triangular_solve.__doc__
upper_triangular_solve.__doc__ = _upper_triangular_solve.__doc__
cholesky_solve.__doc__ = _cholesky_solve.__doc__
LDLsolve.__doc__ = _LDLsolve.__doc__
LUsolve.__doc__ = _LUsolve.__doc__
QRsolve.__doc__ = _QRsolve.__doc__
gauss_jordan_solve.__doc__ = _gauss_jordan_solve.__doc__
pinv_solve.__doc__ = _pinv_solve.__doc__
cramer_solve.__doc__ = _cramer_solve.__doc__
solve.__doc__ = _solve.__doc__
solve_least_squares.__doc__ = _solve_least_squares.__doc__
pinv.__doc__ = _pinv.__doc__
inverse_ADJ.__doc__ = _inv_ADJ.__doc__
inverse_GE.__doc__ = _inv_GE.__doc__
inverse_LU.__doc__ = _inv_LU.__doc__
inverse_CH.__doc__ = _inv_CH.__doc__
inverse_LDL.__doc__ = _inv_LDL.__doc__
inverse_QR.__doc__ = _inv_QR.__doc__
inverse_BLOCK.__doc__ = _inv_block.__doc__
inv.__doc__ = _inv.__doc__
connected_components.__doc__ = _connected_components.__doc__
connected_components_decomposition.__doc__ = \
_connected_components_decomposition.__doc__
strongly_connected_components.__doc__ = \
_strongly_connected_components.__doc__
strongly_connected_components_decomposition.__doc__ = \
_strongly_connected_components_decomposition.__doc__
def _convert_matrix(typ, mat):
"""Convert mat to a Matrix of type typ."""
from sympy.matrices.matrixbase import MatrixBase
if getattr(mat, "is_Matrix", False) and not isinstance(mat, MatrixBase):
# This is needed for interop between Matrix and the redundant matrix
# mixin types like _MinimalMatrix etc. If anyone should happen to be
# using those then this keeps them working. Really _MinimalMatrix etc
# should be deprecated and removed though.
return typ(*mat.shape, list(mat))
else:
return typ(mat)
def _has_matrix_shape(other):
shape = getattr(other, 'shape', None)
if shape is None:
return False
return isinstance(shape, tuple) and len(shape) == 2
def _has_rows_cols(other):
return hasattr(other, 'rows') and hasattr(other, 'cols')
def _coerce_operand(self, other):
"""Convert other to a Matrix, or check for possible scalar."""
INVALID = None, 'invalid_type'
# Disallow mixing Matrix and Array
if isinstance(other, NDimArray):
return INVALID
is_Matrix = getattr(other, 'is_Matrix', None)
# Return a Matrix as-is
if is_Matrix:
return other, 'is_matrix'
# Try to convert numpy array, mpmath matrix etc.
if is_Matrix is None:
if _has_matrix_shape(other) or _has_rows_cols(other):
return _convert_matrix(type(self), other), 'is_matrix'
# Could be a scalar but only if not iterable...
if not isinstance(other, Iterable):
return other, 'possible_scalar'
return INVALID
def classof(A, B):
"""
Get the type of the result when combining matrices of different types.
Currently the strategy is that immutability is contagious.
Examples
========
>>> from sympy import Matrix, ImmutableMatrix
>>> from sympy.matrices.matrixbase import classof
>>> M = Matrix([[1, 2], [3, 4]]) # a Mutable Matrix
>>> IM = ImmutableMatrix([[1, 2], [3, 4]])
>>> classof(M, IM)
<class 'sympy.matrices.immutable.ImmutableDenseMatrix'>
"""
priority_A = getattr(A, '_class_priority', None)
priority_B = getattr(B, '_class_priority', None)
if None not in (priority_A, priority_B):
if A._class_priority > B._class_priority:
return A.__class__
else:
return B.__class__
try:
import numpy
except ImportError:
pass
else:
if isinstance(A, numpy.ndarray):
return B.__class__
if isinstance(B, numpy.ndarray):
return A.__class__
raise TypeError("Incompatible classes %s, %s" % (A.__class__, B.__class__))
def _unify_with_other(self, other):
"""Unify self and other into a single matrix type, or check for scalar."""
other, T = _coerce_operand(self, other)
if T == "is_matrix":
typ = classof(self, other)
if typ != self.__class__:
self = _convert_matrix(typ, self)
if typ != other.__class__:
other = _convert_matrix(typ, other)
return self, other, T
def a2idx(j, n=None):
"""Return integer after making positive and validating against n."""
if not isinstance(j, int):
jindex = getattr(j, '__index__', None)
if jindex is not None:
j = jindex()
else:
raise IndexError("Invalid index a[%r]" % (j,))
if n is not None:
if j < 0:
j += n
if not (j >= 0 and j < n):
raise IndexError("Index out of range: a[%s]" % (j,))
return int(j)
class DeferredVector(Symbol, NotIterable):
"""A vector whose components are deferred (e.g. for use with lambdify).
Examples
========
>>> from sympy import DeferredVector, lambdify
>>> X = DeferredVector( 'X' )
>>> X
X
>>> expr = (X[0] + 2, X[2] + 3)
>>> func = lambdify( X, expr)
>>> func( [1, 2, 3] )
(3, 6)
"""
def __getitem__(self, i):
if i == -0:
i = 0
if i < 0:
raise IndexError('DeferredVector index out of range')
component_name = '%s[%d]' % (self.name, i)
return Symbol(component_name)
def __str__(self):
return sstr(self)
def __repr__(self):
return "DeferredVector('%s')" % self.name
PK ]ZZZ�} �� � sympy/matrices/normalforms.py'''Functions returning normal forms of matrices'''
from sympy.polys.domains.integerring import ZZ
from sympy.polys.polytools import Poly
from sympy.polys.matrices import DomainMatrix
from sympy.polys.matrices.normalforms import (
smith_normal_form as _snf,
invariant_factors as _invf,
hermite_normal_form as _hnf,
)
def _to_domain(m, domain=None):
"""Convert Matrix to DomainMatrix"""
# XXX: deprecated support for RawMatrix:
ring = getattr(m, "ring", None)
m = m.applyfunc(lambda e: e.as_expr() if isinstance(e, Poly) else e)
dM = DomainMatrix.from_Matrix(m)
domain = domain or ring
if domain is not None:
dM = dM.convert_to(domain)
return dM
def smith_normal_form(m, domain=None):
'''
Return the Smith Normal Form of a matrix `m` over the ring `domain`.
This will only work if the ring is a principal ideal domain.
Examples
========
>>> from sympy import Matrix, ZZ
>>> from sympy.matrices.normalforms import smith_normal_form
>>> m = Matrix([[12, 6, 4], [3, 9, 6], [2, 16, 14]])
>>> print(smith_normal_form(m, domain=ZZ))
Matrix([[1, 0, 0], [0, 10, 0], [0, 0, -30]])
'''
dM = _to_domain(m, domain)
return _snf(dM).to_Matrix()
def invariant_factors(m, domain=None):
'''
Return the tuple of abelian invariants for a matrix `m`
(as in the Smith-Normal form)
References
==========
.. [1] https://en.wikipedia.org/wiki/Smith_normal_form#Algorithm
.. [2] https://web.archive.org/web/20200331143852/https://sierra.nmsu.edu/morandi/notes/SmithNormalForm.pdf
'''
dM = _to_domain(m, domain)
factors = _invf(dM)
factors = tuple(dM.domain.to_sympy(f) for f in factors)
# XXX: deprecated.
if hasattr(m, "ring"):
if m.ring.is_PolynomialRing:
K = m.ring
to_poly = lambda f: Poly(f, K.symbols, domain=K.domain)
factors = tuple(to_poly(f) for f in factors)
return factors
def hermite_normal_form(A, *, D=None, check_rank=False):
r"""
Compute the Hermite Normal Form of a Matrix *A* of integers.
Examples
========
>>> from sympy import Matrix
>>> from sympy.matrices.normalforms import hermite_normal_form
>>> m = Matrix([[12, 6, 4], [3, 9, 6], [2, 16, 14]])
>>> print(hermite_normal_form(m))
Matrix([[10, 0, 2], [0, 15, 3], [0, 0, 2]])
Parameters
==========
A : $m \times n$ ``Matrix`` of integers.
D : int, optional
Let $W$ be the HNF of *A*. If known in advance, a positive integer *D*
being any multiple of $\det(W)$ may be provided. In this case, if *A*
also has rank $m$, then we may use an alternative algorithm that works
mod *D* in order to prevent coefficient explosion.
check_rank : boolean, optional (default=False)
The basic assumption is that, if you pass a value for *D*, then
you already believe that *A* has rank $m$, so we do not waste time
checking it for you. If you do want this to be checked (and the
ordinary, non-modulo *D* algorithm to be used if the check fails), then
set *check_rank* to ``True``.
Returns
=======
``Matrix``
The HNF of matrix *A*.
Raises
======
DMDomainError
If the domain of the matrix is not :ref:`ZZ`.
DMShapeError
If the mod *D* algorithm is used but the matrix has more rows than
columns.
References
==========
.. [1] Cohen, H. *A Course in Computational Algebraic Number Theory.*
(See Algorithms 2.4.5 and 2.4.8.)
"""
# Accept any of Python int, SymPy Integer, and ZZ itself:
if D is not None and not ZZ.of_type(D):
D = ZZ(int(D))
return _hnf(A._rep, D=D, check_rank=check_rank).to_Matrix()
PK ]ZZZ���Q�0 �0 sympy/matrices/reductions.pyfrom types import FunctionType
from sympy.polys.polyerrors import CoercionFailed
from sympy.polys.domains import ZZ, QQ
from .utilities import _get_intermediate_simp, _iszero, _dotprodsimp, _simplify
from .determinant import _find_reasonable_pivot
def _row_reduce_list(mat, rows, cols, one, iszerofunc, simpfunc,
normalize_last=True, normalize=True, zero_above=True):
"""Row reduce a flat list representation of a matrix and return a tuple
(rref_matrix, pivot_cols, swaps) where ``rref_matrix`` is a flat list,
``pivot_cols`` are the pivot columns and ``swaps`` are any row swaps that
were used in the process of row reduction.
Parameters
==========
mat : list
list of matrix elements, must be ``rows`` * ``cols`` in length
rows, cols : integer
number of rows and columns in flat list representation
one : SymPy object
represents the value one, from ``Matrix.one``
iszerofunc : determines if an entry can be used as a pivot
simpfunc : used to simplify elements and test if they are
zero if ``iszerofunc`` returns `None`
normalize_last : indicates where all row reduction should
happen in a fraction-free manner and then the rows are
normalized (so that the pivots are 1), or whether
rows should be normalized along the way (like the naive
row reduction algorithm)
normalize : whether pivot rows should be normalized so that
the pivot value is 1
zero_above : whether entries above the pivot should be zeroed.
If ``zero_above=False``, an echelon matrix will be returned.
"""
def get_col(i):
return mat[i::cols]
def row_swap(i, j):
mat[i*cols:(i + 1)*cols], mat[j*cols:(j + 1)*cols] = \
mat[j*cols:(j + 1)*cols], mat[i*cols:(i + 1)*cols]
def cross_cancel(a, i, b, j):
"""Does the row op row[i] = a*row[i] - b*row[j]"""
q = (j - i)*cols
for p in range(i*cols, (i + 1)*cols):
mat[p] = isimp(a*mat[p] - b*mat[p + q])
isimp = _get_intermediate_simp(_dotprodsimp)
piv_row, piv_col = 0, 0
pivot_cols = []
swaps = []
# use a fraction free method to zero above and below each pivot
while piv_col < cols and piv_row < rows:
pivot_offset, pivot_val, \
assumed_nonzero, newly_determined = _find_reasonable_pivot(
get_col(piv_col)[piv_row:], iszerofunc, simpfunc)
# _find_reasonable_pivot may have simplified some things
# in the process. Let's not let them go to waste
for (offset, val) in newly_determined:
offset += piv_row
mat[offset*cols + piv_col] = val
if pivot_offset is None:
piv_col += 1
continue
pivot_cols.append(piv_col)
if pivot_offset != 0:
row_swap(piv_row, pivot_offset + piv_row)
swaps.append((piv_row, pivot_offset + piv_row))
# if we aren't normalizing last, we normalize
# before we zero the other rows
if normalize_last is False:
i, j = piv_row, piv_col
mat[i*cols + j] = one
for p in range(i*cols + j + 1, (i + 1)*cols):
mat[p] = isimp(mat[p] / pivot_val)
# after normalizing, the pivot value is 1
pivot_val = one
# zero above and below the pivot
for row in range(rows):
# don't zero our current row
if row == piv_row:
continue
# don't zero above the pivot unless we're told.
if zero_above is False and row < piv_row:
continue
# if we're already a zero, don't do anything
val = mat[row*cols + piv_col]
if iszerofunc(val):
continue
cross_cancel(pivot_val, row, val, piv_row)
piv_row += 1
# normalize each row
if normalize_last is True and normalize is True:
for piv_i, piv_j in enumerate(pivot_cols):
pivot_val = mat[piv_i*cols + piv_j]
mat[piv_i*cols + piv_j] = one
for p in range(piv_i*cols + piv_j + 1, (piv_i + 1)*cols):
mat[p] = isimp(mat[p] / pivot_val)
return mat, tuple(pivot_cols), tuple(swaps)
# This functions is a candidate for caching if it gets implemented for matrices.
def _row_reduce(M, iszerofunc, simpfunc, normalize_last=True,
normalize=True, zero_above=True):
mat, pivot_cols, swaps = _row_reduce_list(list(M), M.rows, M.cols, M.one,
iszerofunc, simpfunc, normalize_last=normalize_last,
normalize=normalize, zero_above=zero_above)
return M._new(M.rows, M.cols, mat), pivot_cols, swaps
def _is_echelon(M, iszerofunc=_iszero):
"""Returns `True` if the matrix is in echelon form. That is, all rows of
zeros are at the bottom, and below each leading non-zero in a row are
exclusively zeros."""
if M.rows <= 0 or M.cols <= 0:
return True
zeros_below = all(iszerofunc(t) for t in M[1:, 0])
if iszerofunc(M[0, 0]):
return zeros_below and _is_echelon(M[:, 1:], iszerofunc)
return zeros_below and _is_echelon(M[1:, 1:], iszerofunc)
def _echelon_form(M, iszerofunc=_iszero, simplify=False, with_pivots=False):
"""Returns a matrix row-equivalent to ``M`` that is in echelon form. Note
that echelon form of a matrix is *not* unique, however, properties like the
row space and the null space are preserved.
Examples
========
>>> from sympy import Matrix
>>> M = Matrix([[1, 2], [3, 4]])
>>> M.echelon_form()
Matrix([
[1, 2],
[0, -2]])
"""
simpfunc = simplify if isinstance(simplify, FunctionType) else _simplify
mat, pivots, _ = _row_reduce(M, iszerofunc, simpfunc,
normalize_last=True, normalize=False, zero_above=False)
if with_pivots:
return mat, pivots
return mat
# This functions is a candidate for caching if it gets implemented for matrices.
def _rank(M, iszerofunc=_iszero, simplify=False):
"""Returns the rank of a matrix.
Examples
========
>>> from sympy import Matrix
>>> from sympy.abc import x
>>> m = Matrix([[1, 2], [x, 1 - 1/x]])
>>> m.rank()
2
>>> n = Matrix(3, 3, range(1, 10))
>>> n.rank()
2
"""
def _permute_complexity_right(M, iszerofunc):
"""Permute columns with complicated elements as
far right as they can go. Since the ``sympy`` row reduction
algorithms start on the left, having complexity right-shifted
speeds things up.
Returns a tuple (mat, perm) where perm is a permutation
of the columns to perform to shift the complex columns right, and mat
is the permuted matrix."""
def complexity(i):
# the complexity of a column will be judged by how many
# element's zero-ness cannot be determined
return sum(1 if iszerofunc(e) is None else 0 for e in M[:, i])
complex = [(complexity(i), i) for i in range(M.cols)]
perm = [j for (i, j) in sorted(complex)]
return (M.permute(perm, orientation='cols'), perm)
simpfunc = simplify if isinstance(simplify, FunctionType) else _simplify
# for small matrices, we compute the rank explicitly
# if is_zero on elements doesn't answer the question
# for small matrices, we fall back to the full routine.
if M.rows <= 0 or M.cols <= 0:
return 0
if M.rows <= 1 or M.cols <= 1:
zeros = [iszerofunc(x) for x in M]
if False in zeros:
return 1
if M.rows == 2 and M.cols == 2:
zeros = [iszerofunc(x) for x in M]
if False not in zeros and None not in zeros:
return 0
d = M.det()
if iszerofunc(d) and False in zeros:
return 1
if iszerofunc(d) is False:
return 2
mat, _ = _permute_complexity_right(M, iszerofunc=iszerofunc)
_, pivots, _ = _row_reduce(mat, iszerofunc, simpfunc, normalize_last=True,
normalize=False, zero_above=False)
return len(pivots)
def _to_DM_ZZ_QQ(M):
# We have to test for _rep here because there are tests that otherwise fail
# with e.g. "AttributeError: 'SubspaceOnlyMatrix' object has no attribute
# '_rep'." There is almost certainly no value in such tests. The
# presumption seems to be that someone could create a new class by
# inheriting some of the Matrix classes and not the full set that is used
# by the standard Matrix class but if anyone tried that it would fail in
# many ways.
if not hasattr(M, '_rep'):
return None
rep = M._rep
K = rep.domain
if K.is_ZZ:
return rep
elif K.is_QQ:
try:
return rep.convert_to(ZZ)
except CoercionFailed:
return rep
else:
if not all(e.is_Rational for e in M):
return None
try:
return rep.convert_to(ZZ)
except CoercionFailed:
return rep.convert_to(QQ)
def _rref_dm(dM):
"""Compute the reduced row echelon form of a DomainMatrix."""
K = dM.domain
if K.is_ZZ:
dM_rref, den, pivots = dM.rref_den(keep_domain=False)
dM_rref = dM_rref.to_field() / den
elif K.is_QQ:
dM_rref, pivots = dM.rref()
else:
assert False # pragma: no cover
M_rref = dM_rref.to_Matrix()
return M_rref, pivots
def _rref(M, iszerofunc=_iszero, simplify=False, pivots=True,
normalize_last=True):
"""Return reduced row-echelon form of matrix and indices
of pivot vars.
Parameters
==========
iszerofunc : Function
A function used for detecting whether an element can
act as a pivot. ``lambda x: x.is_zero`` is used by default.
simplify : Function
A function used to simplify elements when looking for a pivot.
By default SymPy's ``simplify`` is used.
pivots : True or False
If ``True``, a tuple containing the row-reduced matrix and a tuple
of pivot columns is returned. If ``False`` just the row-reduced
matrix is returned.
normalize_last : True or False
If ``True``, no pivots are normalized to `1` until after all
entries above and below each pivot are zeroed. This means the row
reduction algorithm is fraction free until the very last step.
If ``False``, the naive row reduction procedure is used where
each pivot is normalized to be `1` before row operations are
used to zero above and below the pivot.
Examples
========
>>> from sympy import Matrix
>>> from sympy.abc import x
>>> m = Matrix([[1, 2], [x, 1 - 1/x]])
>>> m.rref()
(Matrix([
[1, 0],
[0, 1]]), (0, 1))
>>> rref_matrix, rref_pivots = m.rref()
>>> rref_matrix
Matrix([
[1, 0],
[0, 1]])
>>> rref_pivots
(0, 1)
``iszerofunc`` can correct rounding errors in matrices with float
values. In the following example, calling ``rref()`` leads to
floating point errors, incorrectly row reducing the matrix.
``iszerofunc= lambda x: abs(x) < 1e-9`` sets sufficiently small numbers
to zero, avoiding this error.
>>> m = Matrix([[0.9, -0.1, -0.2, 0], [-0.8, 0.9, -0.4, 0], [-0.1, -0.8, 0.6, 0]])
>>> m.rref()
(Matrix([
[1, 0, 0, 0],
[0, 1, 0, 0],
[0, 0, 1, 0]]), (0, 1, 2))
>>> m.rref(iszerofunc=lambda x:abs(x)<1e-9)
(Matrix([
[1, 0, -0.301369863013699, 0],
[0, 1, -0.712328767123288, 0],
[0, 0, 0, 0]]), (0, 1))
Notes
=====
The default value of ``normalize_last=True`` can provide significant
speedup to row reduction, especially on matrices with symbols. However,
if you depend on the form row reduction algorithm leaves entries
of the matrix, set ``normalize_last=False``
"""
# Try to use DomainMatrix for ZZ or QQ
dM = _to_DM_ZZ_QQ(M)
if dM is not None:
# Use DomainMatrix for ZZ or QQ
mat, pivot_cols = _rref_dm(dM)
else:
# Use the generic Matrix routine.
if isinstance(simplify, FunctionType):
simpfunc = simplify
else:
simpfunc = _simplify
mat, pivot_cols, _ = _row_reduce(M, iszerofunc, simpfunc,
normalize_last, normalize=True, zero_above=True)
if pivots:
return mat, pivot_cols
else:
return mat
PK ]ZZZ�z�r�s �s sympy/matrices/repmatrix.pyfrom collections import defaultdict
from operator import index as index_
from sympy.core.expr import Expr
from sympy.core.kind import Kind, NumberKind, UndefinedKind
from sympy.core.numbers import Integer, Rational
from sympy.core.sympify import _sympify, SympifyError
from sympy.core.singleton import S
from sympy.polys.domains import ZZ, QQ, GF, EXRAW
from sympy.polys.matrices import DomainMatrix
from sympy.polys.matrices.exceptions import DMNonInvertibleMatrixError
from sympy.polys.polyerrors import CoercionFailed
from sympy.utilities.exceptions import sympy_deprecation_warning
from sympy.utilities.iterables import is_sequence
from sympy.utilities.misc import filldedent, as_int
from .exceptions import ShapeError, NonSquareMatrixError, NonInvertibleMatrixError
from .matrixbase import classof, MatrixBase
from .kind import MatrixKind
class RepMatrix(MatrixBase):
"""Matrix implementation based on DomainMatrix as an internal representation.
The RepMatrix class is a superclass for Matrix, ImmutableMatrix,
SparseMatrix and ImmutableSparseMatrix which are the main usable matrix
classes in SymPy. Most methods on this class are simply forwarded to
DomainMatrix.
"""
#
# MatrixBase is the common superclass for all of the usable explicit matrix
# classes in SymPy. The idea is that MatrixBase is an abstract class though
# and that subclasses will implement the lower-level methods.
#
# RepMatrix is a subclass of MatrixBase that uses DomainMatrix as an
# internal representation and delegates lower-level methods to
# DomainMatrix. All of SymPy's standard explicit matrix classes subclass
# RepMatrix and so use DomainMatrix internally.
#
# A RepMatrix uses an internal DomainMatrix with the domain set to ZZ, QQ
# or EXRAW. The EXRAW domain is equivalent to the previous implementation
# of Matrix that used Expr for the elements. The ZZ and QQ domains are used
# when applicable just because they are compatible with the previous
# implementation but are much more efficient. Other domains such as QQ[x]
# are not used because they differ from Expr in some way (e.g. automatic
# expansion of powers and products).
#
_rep: DomainMatrix
def __eq__(self, other):
# Skip sympify for mutable matrices...
if not isinstance(other, RepMatrix):
try:
other = _sympify(other)
except SympifyError:
return NotImplemented
if not isinstance(other, RepMatrix):
return NotImplemented
return self._rep.unify_eq(other._rep)
def to_DM(self, domain=None, **kwargs):
"""Convert to a :class:`~.DomainMatrix`.
Examples
========
>>> from sympy import Matrix
>>> M = Matrix([[1, 2], [3, 4]])
>>> M.to_DM()
DomainMatrix({0: {0: 1, 1: 2}, 1: {0: 3, 1: 4}}, (2, 2), ZZ)
The :meth:`DomainMatrix.to_Matrix` method can be used to convert back:
>>> M.to_DM().to_Matrix() == M
True
The domain can be given explicitly or otherwise it will be chosen by
:func:`construct_domain`. Any keyword arguments (besides ``domain``)
are passed to :func:`construct_domain`:
>>> from sympy import QQ, symbols
>>> x = symbols('x')
>>> M = Matrix([[x, 1], [1, x]])
>>> M
Matrix([
[x, 1],
[1, x]])
>>> M.to_DM().domain
ZZ[x]
>>> M.to_DM(field=True).domain
ZZ(x)
>>> M.to_DM(domain=QQ[x]).domain
QQ[x]
See Also
========
DomainMatrix
DomainMatrix.to_Matrix
DomainMatrix.convert_to
DomainMatrix.choose_domain
construct_domain
"""
if domain is not None:
if kwargs:
raise TypeError("Options cannot be used with domain parameter")
return self._rep.convert_to(domain)
rep = self._rep
dom = rep.domain
# If the internal DomainMatrix is already ZZ or QQ then we can maybe
# bypass calling construct_domain or performing any conversions. Some
# kwargs might affect this though e.g. field=True (not sure if there
# are others).
if not kwargs:
if dom.is_ZZ:
return rep.copy()
elif dom.is_QQ:
# All elements might be integers
try:
return rep.convert_to(ZZ)
except CoercionFailed:
pass
return rep.copy()
# Let construct_domain choose a domain
rep_dom = rep.choose_domain(**kwargs)
# XXX: There should be an option to construct_domain to choose EXRAW
# instead of EX. At least converting to EX does not initially trigger
# EX.simplify which is what we want here but should probably be
# considered a bug in EX. Perhaps also this could be handled in
# DomainMatrix.choose_domain rather than here...
if rep_dom.domain.is_EX:
rep_dom = rep_dom.convert_to(EXRAW)
return rep_dom
@classmethod
def _unify_element_sympy(cls, rep, element):
domain = rep.domain
element = _sympify(element)
if domain != EXRAW:
# The domain can only be ZZ, QQ or EXRAW
if element.is_Integer:
new_domain = domain
elif element.is_Rational:
new_domain = QQ
else:
new_domain = EXRAW
# XXX: This converts the domain for all elements in the matrix
# which can be slow. This happens e.g. if __setitem__ changes one
# element to something that does not fit in the domain
if new_domain != domain:
rep = rep.convert_to(new_domain)
domain = new_domain
if domain != EXRAW:
element = new_domain.from_sympy(element)
if domain == EXRAW and not isinstance(element, Expr):
sympy_deprecation_warning(
"""
non-Expr objects in a Matrix is deprecated. Matrix represents
a mathematical matrix. To represent a container of non-numeric
entities, Use a list of lists, TableForm, NumPy array, or some
other data structure instead.
""",
deprecated_since_version="1.9",
active_deprecations_target="deprecated-non-expr-in-matrix",
stacklevel=4,
)
return rep, element
@classmethod
def _dod_to_DomainMatrix(cls, rows, cols, dod, types):
if not all(issubclass(typ, Expr) for typ in types):
sympy_deprecation_warning(
"""
non-Expr objects in a Matrix is deprecated. Matrix represents
a mathematical matrix. To represent a container of non-numeric
entities, Use a list of lists, TableForm, NumPy array, or some
other data structure instead.
""",
deprecated_since_version="1.9",
active_deprecations_target="deprecated-non-expr-in-matrix",
stacklevel=6,
)
rep = DomainMatrix(dod, (rows, cols), EXRAW)
if all(issubclass(typ, Rational) for typ in types):
if all(issubclass(typ, Integer) for typ in types):
rep = rep.convert_to(ZZ)
else:
rep = rep.convert_to(QQ)
return rep
@classmethod
def _flat_list_to_DomainMatrix(cls, rows, cols, flat_list):
elements_dod = defaultdict(dict)
for n, element in enumerate(flat_list):
if element != 0:
i, j = divmod(n, cols)
elements_dod[i][j] = element
types = set(map(type, flat_list))
rep = cls._dod_to_DomainMatrix(rows, cols, elements_dod, types)
return rep
@classmethod
def _smat_to_DomainMatrix(cls, rows, cols, smat):
elements_dod = defaultdict(dict)
for (i, j), element in smat.items():
if element != 0:
elements_dod[i][j] = element
types = set(map(type, smat.values()))
rep = cls._dod_to_DomainMatrix(rows, cols, elements_dod, types)
return rep
def flat(self):
return self._rep.to_sympy().to_list_flat()
def _eval_tolist(self):
return self._rep.to_sympy().to_list()
def _eval_todok(self):
return self._rep.to_sympy().to_dok()
@classmethod
def _eval_from_dok(cls, rows, cols, dok):
return cls._fromrep(cls._smat_to_DomainMatrix(rows, cols, dok))
def _eval_values(self):
return list(self._eval_iter_values())
def _eval_iter_values(self):
rep = self._rep
K = rep.domain
values = rep.iter_values()
if not K.is_EXRAW:
values = map(K.to_sympy, values)
return values
def _eval_iter_items(self):
rep = self._rep
K = rep.domain
to_sympy = K.to_sympy
items = rep.iter_items()
if not K.is_EXRAW:
items = ((i, to_sympy(v)) for i, v in items)
return items
def copy(self):
return self._fromrep(self._rep.copy())
@property
def kind(self) -> MatrixKind:
domain = self._rep.domain
element_kind: Kind
if domain in (ZZ, QQ):
element_kind = NumberKind
elif domain == EXRAW:
kinds = {e.kind for e in self.values()}
if len(kinds) == 1:
[element_kind] = kinds
else:
element_kind = UndefinedKind
else: # pragma: no cover
raise RuntimeError("Domain should only be ZZ, QQ or EXRAW")
return MatrixKind(element_kind)
def _eval_has(self, *patterns):
# if the matrix has any zeros, see if S.Zero
# has the pattern. If _smat is full length,
# the matrix has no zeros.
zhas = False
dok = self.todok()
if len(dok) != self.rows*self.cols:
zhas = S.Zero.has(*patterns)
return zhas or any(value.has(*patterns) for value in dok.values())
def _eval_is_Identity(self):
if not all(self[i, i] == 1 for i in range(self.rows)):
return False
return len(self.todok()) == self.rows
def _eval_is_symmetric(self, simpfunc):
diff = (self - self.T).applyfunc(simpfunc)
return len(diff.values()) == 0
def _eval_transpose(self):
"""Returns the transposed SparseMatrix of this SparseMatrix.
Examples
========
>>> from sympy import SparseMatrix
>>> a = SparseMatrix(((1, 2), (3, 4)))
>>> a
Matrix([
[1, 2],
[3, 4]])
>>> a.T
Matrix([
[1, 3],
[2, 4]])
"""
return self._fromrep(self._rep.transpose())
def _eval_col_join(self, other):
return self._fromrep(self._rep.vstack(other._rep))
def _eval_row_join(self, other):
return self._fromrep(self._rep.hstack(other._rep))
def _eval_extract(self, rowsList, colsList):
return self._fromrep(self._rep.extract(rowsList, colsList))
def __getitem__(self, key):
return _getitem_RepMatrix(self, key)
@classmethod
def _eval_zeros(cls, rows, cols):
rep = DomainMatrix.zeros((rows, cols), ZZ)
return cls._fromrep(rep)
@classmethod
def _eval_eye(cls, rows, cols):
rep = DomainMatrix.eye((rows, cols), ZZ)
return cls._fromrep(rep)
def _eval_add(self, other):
return classof(self, other)._fromrep(self._rep + other._rep)
def _eval_matrix_mul(self, other):
return classof(self, other)._fromrep(self._rep * other._rep)
def _eval_matrix_mul_elementwise(self, other):
selfrep, otherrep = self._rep.unify(other._rep)
newrep = selfrep.mul_elementwise(otherrep)
return classof(self, other)._fromrep(newrep)
def _eval_scalar_mul(self, other):
rep, other = self._unify_element_sympy(self._rep, other)
return self._fromrep(rep.scalarmul(other))
def _eval_scalar_rmul(self, other):
rep, other = self._unify_element_sympy(self._rep, other)
return self._fromrep(rep.rscalarmul(other))
def _eval_Abs(self):
return self._fromrep(self._rep.applyfunc(abs))
def _eval_conjugate(self):
rep = self._rep
domain = rep.domain
if domain in (ZZ, QQ):
return self.copy()
else:
return self._fromrep(rep.applyfunc(lambda e: e.conjugate()))
def equals(self, other, failing_expression=False):
"""Applies ``equals`` to corresponding elements of the matrices,
trying to prove that the elements are equivalent, returning True
if they are, False if any pair is not, and None (or the first
failing expression if failing_expression is True) if it cannot
be decided if the expressions are equivalent or not. This is, in
general, an expensive operation.
Examples
========
>>> from sympy import Matrix
>>> from sympy.abc import x
>>> A = Matrix([x*(x - 1), 0])
>>> B = Matrix([x**2 - x, 0])
>>> A == B
False
>>> A.simplify() == B.simplify()
True
>>> A.equals(B)
True
>>> A.equals(2)
False
See Also
========
sympy.core.expr.Expr.equals
"""
if self.shape != getattr(other, 'shape', None):
return False
rv = True
for i in range(self.rows):
for j in range(self.cols):
ans = self[i, j].equals(other[i, j], failing_expression)
if ans is False:
return False
elif ans is not True and rv is True:
rv = ans
return rv
def inv_mod(M, m):
r"""
Returns the inverse of the integer matrix ``M`` modulo ``m``.
Examples
========
>>> from sympy import Matrix
>>> A = Matrix(2, 2, [1, 2, 3, 4])
>>> A.inv_mod(5)
Matrix([
[3, 1],
[4, 2]])
>>> A.inv_mod(3)
Matrix([
[1, 1],
[0, 1]])
"""
if not M.is_square:
raise NonSquareMatrixError()
try:
m = as_int(m)
except ValueError:
raise TypeError("inv_mod: modulus m must be an integer")
K = GF(m, symmetric=False)
try:
dM = M.to_DM(K)
except CoercionFailed:
raise ValueError("inv_mod: matrix entries must be integers")
try:
dMi = dM.inv()
except DMNonInvertibleMatrixError as exc:
msg = f'Matrix is not invertible (mod {m})'
raise NonInvertibleMatrixError(msg) from exc
return dMi.to_Matrix()
def lll(self, delta=0.75):
"""LLL-reduced basis for the rowspace of a matrix of integers.
Performs the Lenstra–Lenstra–Lovász (LLL) basis reduction algorithm.
The implementation is provided by :class:`~DomainMatrix`. See
:meth:`~DomainMatrix.lll` for more details.
Examples
========
>>> from sympy import Matrix
>>> M = Matrix([[1, 0, 0, 0, -20160],
... [0, 1, 0, 0, 33768],
... [0, 0, 1, 0, 39578],
... [0, 0, 0, 1, 47757]])
>>> M.lll()
Matrix([
[ 10, -3, -2, 8, -4],
[ 3, -9, 8, 1, -11],
[ -3, 13, -9, -3, -9],
[-12, -7, -11, 9, -1]])
See Also
========
lll_transform
sympy.polys.matrices.domainmatrix.DomainMatrix.lll
"""
delta = QQ.from_sympy(_sympify(delta))
dM = self._rep.convert_to(ZZ)
basis = dM.lll(delta=delta)
return self._fromrep(basis)
def lll_transform(self, delta=0.75):
"""LLL-reduced basis and transformation matrix.
Performs the Lenstra–Lenstra–Lovász (LLL) basis reduction algorithm.
The implementation is provided by :class:`~DomainMatrix`. See
:meth:`~DomainMatrix.lll_transform` for more details.
Examples
========
>>> from sympy import Matrix
>>> M = Matrix([[1, 0, 0, 0, -20160],
... [0, 1, 0, 0, 33768],
... [0, 0, 1, 0, 39578],
... [0, 0, 0, 1, 47757]])
>>> B, T = M.lll_transform()
>>> B
Matrix([
[ 10, -3, -2, 8, -4],
[ 3, -9, 8, 1, -11],
[ -3, 13, -9, -3, -9],
[-12, -7, -11, 9, -1]])
>>> T
Matrix([
[ 10, -3, -2, 8],
[ 3, -9, 8, 1],
[ -3, 13, -9, -3],
[-12, -7, -11, 9]])
The transformation matrix maps the original basis to the LLL-reduced
basis:
>>> T * M == B
True
See Also
========
lll
sympy.polys.matrices.domainmatrix.DomainMatrix.lll_transform
"""
delta = QQ.from_sympy(_sympify(delta))
dM = self._rep.convert_to(ZZ)
basis, transform = dM.lll_transform(delta=delta)
B = self._fromrep(basis)
T = self._fromrep(transform)
return B, T
class MutableRepMatrix(RepMatrix):
"""Mutable matrix based on DomainMatrix as the internal representation"""
#
# MutableRepMatrix is a subclass of RepMatrix that adds/overrides methods
# to make the instances mutable. MutableRepMatrix is a superclass for both
# MutableDenseMatrix and MutableSparseMatrix.
#
is_zero = False
def __new__(cls, *args, **kwargs):
return cls._new(*args, **kwargs)
@classmethod
def _new(cls, *args, copy=True, **kwargs):
if copy is False:
# The input was rows, cols, [list].
# It should be used directly without creating a copy.
if len(args) != 3:
raise TypeError("'copy=False' requires a matrix be initialized as rows,cols,[list]")
rows, cols, flat_list = args
else:
rows, cols, flat_list = cls._handle_creation_inputs(*args, **kwargs)
flat_list = list(flat_list) # create a shallow copy
rep = cls._flat_list_to_DomainMatrix(rows, cols, flat_list)
return cls._fromrep(rep)
@classmethod
def _fromrep(cls, rep):
obj = super().__new__(cls)
obj.rows, obj.cols = rep.shape
obj._rep = rep
return obj
def copy(self):
return self._fromrep(self._rep.copy())
def as_mutable(self):
return self.copy()
def __setitem__(self, key, value):
"""
Examples
========
>>> from sympy import Matrix, I, zeros, ones
>>> m = Matrix(((1, 2+I), (3, 4)))
>>> m
Matrix([
[1, 2 + I],
[3, 4]])
>>> m[1, 0] = 9
>>> m
Matrix([
[1, 2 + I],
[9, 4]])
>>> m[1, 0] = [[0, 1]]
To replace row r you assign to position r*m where m
is the number of columns:
>>> M = zeros(4)
>>> m = M.cols
>>> M[3*m] = ones(1, m)*2; M
Matrix([
[0, 0, 0, 0],
[0, 0, 0, 0],
[0, 0, 0, 0],
[2, 2, 2, 2]])
And to replace column c you can assign to position c:
>>> M[2] = ones(m, 1)*4; M
Matrix([
[0, 0, 4, 0],
[0, 0, 4, 0],
[0, 0, 4, 0],
[2, 2, 4, 2]])
"""
rv = self._setitem(key, value)
if rv is not None:
i, j, value = rv
self._rep, value = self._unify_element_sympy(self._rep, value)
self._rep.rep.setitem(i, j, value)
def _eval_col_del(self, col):
self._rep = DomainMatrix.hstack(self._rep[:,:col], self._rep[:,col+1:])
self.cols -= 1
def _eval_row_del(self, row):
self._rep = DomainMatrix.vstack(self._rep[:row,:], self._rep[row+1:, :])
self.rows -= 1
def _eval_col_insert(self, col, other):
other = self._new(other)
return self.hstack(self[:,:col], other, self[:,col:])
def _eval_row_insert(self, row, other):
other = self._new(other)
return self.vstack(self[:row,:], other, self[row:,:])
def col_op(self, j, f):
"""In-place operation on col j using two-arg functor whose args are
interpreted as (self[i, j], i).
Examples
========
>>> from sympy import eye
>>> M = eye(3)
>>> M.col_op(1, lambda v, i: v + 2*M[i, 0]); M
Matrix([
[1, 2, 0],
[0, 1, 0],
[0, 0, 1]])
See Also
========
col
row_op
"""
for i in range(self.rows):
self[i, j] = f(self[i, j], i)
def col_swap(self, i, j):
"""Swap the two given columns of the matrix in-place.
Examples
========
>>> from sympy import Matrix
>>> M = Matrix([[1, 0], [1, 0]])
>>> M
Matrix([
[1, 0],
[1, 0]])
>>> M.col_swap(0, 1)
>>> M
Matrix([
[0, 1],
[0, 1]])
See Also
========
col
row_swap
"""
for k in range(0, self.rows):
self[k, i], self[k, j] = self[k, j], self[k, i]
def row_op(self, i, f):
"""In-place operation on row ``i`` using two-arg functor whose args are
interpreted as ``(self[i, j], j)``.
Examples
========
>>> from sympy import eye
>>> M = eye(3)
>>> M.row_op(1, lambda v, j: v + 2*M[0, j]); M
Matrix([
[1, 0, 0],
[2, 1, 0],
[0, 0, 1]])
See Also
========
row
zip_row_op
col_op
"""
for j in range(self.cols):
self[i, j] = f(self[i, j], j)
#The next three methods give direct support for the most common row operations inplace.
def row_mult(self,i,factor):
"""Multiply the given row by the given factor in-place.
Examples
========
>>> from sympy import eye
>>> M = eye(3)
>>> M.row_mult(1,7); M
Matrix([
[1, 0, 0],
[0, 7, 0],
[0, 0, 1]])
"""
for j in range(self.cols):
self[i,j] *= factor
def row_add(self,s,t,k):
"""Add k times row s (source) to row t (target) in place.
Examples
========
>>> from sympy import eye
>>> M = eye(3)
>>> M.row_add(0, 2,3); M
Matrix([
[1, 0, 0],
[0, 1, 0],
[3, 0, 1]])
"""
for j in range(self.cols):
self[t,j] += k*self[s,j]
def row_swap(self, i, j):
"""Swap the two given rows of the matrix in-place.
Examples
========
>>> from sympy import Matrix
>>> M = Matrix([[0, 1], [1, 0]])
>>> M
Matrix([
[0, 1],
[1, 0]])
>>> M.row_swap(0, 1)
>>> M
Matrix([
[1, 0],
[0, 1]])
See Also
========
row
col_swap
"""
for k in range(0, self.cols):
self[i, k], self[j, k] = self[j, k], self[i, k]
def zip_row_op(self, i, k, f):
"""In-place operation on row ``i`` using two-arg functor whose args are
interpreted as ``(self[i, j], self[k, j])``.
Examples
========
>>> from sympy import eye
>>> M = eye(3)
>>> M.zip_row_op(1, 0, lambda v, u: v + 2*u); M
Matrix([
[1, 0, 0],
[2, 1, 0],
[0, 0, 1]])
See Also
========
row
row_op
col_op
"""
for j in range(self.cols):
self[i, j] = f(self[i, j], self[k, j])
def copyin_list(self, key, value):
"""Copy in elements from a list.
Parameters
==========
key : slice
The section of this matrix to replace.
value : iterable
The iterable to copy values from.
Examples
========
>>> from sympy import eye
>>> I = eye(3)
>>> I[:2, 0] = [1, 2] # col
>>> I
Matrix([
[1, 0, 0],
[2, 1, 0],
[0, 0, 1]])
>>> I[1, :2] = [[3, 4]]
>>> I
Matrix([
[1, 0, 0],
[3, 4, 0],
[0, 0, 1]])
See Also
========
copyin_matrix
"""
if not is_sequence(value):
raise TypeError("`value` must be an ordered iterable, not %s." % type(value))
return self.copyin_matrix(key, type(self)(value))
def copyin_matrix(self, key, value):
"""Copy in values from a matrix into the given bounds.
Parameters
==========
key : slice
The section of this matrix to replace.
value : Matrix
The matrix to copy values from.
Examples
========
>>> from sympy import Matrix, eye
>>> M = Matrix([[0, 1], [2, 3], [4, 5]])
>>> I = eye(3)
>>> I[:3, :2] = M
>>> I
Matrix([
[0, 1, 0],
[2, 3, 0],
[4, 5, 1]])
>>> I[0, 1] = M
>>> I
Matrix([
[0, 0, 1],
[2, 2, 3],
[4, 4, 5]])
See Also
========
copyin_list
"""
rlo, rhi, clo, chi = self.key2bounds(key)
shape = value.shape
dr, dc = rhi - rlo, chi - clo
if shape != (dr, dc):
raise ShapeError(filldedent("The Matrix `value` doesn't have the "
"same dimensions "
"as the in sub-Matrix given by `key`."))
for i in range(value.rows):
for j in range(value.cols):
self[i + rlo, j + clo] = value[i, j]
def fill(self, value):
"""Fill self with the given value.
Notes
=====
Unless many values are going to be deleted (i.e. set to zero)
this will create a matrix that is slower than a dense matrix in
operations.
Examples
========
>>> from sympy import SparseMatrix
>>> M = SparseMatrix.zeros(3); M
Matrix([
[0, 0, 0],
[0, 0, 0],
[0, 0, 0]])
>>> M.fill(1); M
Matrix([
[1, 1, 1],
[1, 1, 1],
[1, 1, 1]])
See Also
========
zeros
ones
"""
value = _sympify(value)
if not value:
self._rep = DomainMatrix.zeros(self.shape, EXRAW)
else:
elements_dod = {i: dict.fromkeys(range(self.cols), value) for i in range(self.rows)}
self._rep = DomainMatrix(elements_dod, self.shape, EXRAW)
def _getitem_RepMatrix(self, key):
"""Return portion of self defined by key. If the key involves a slice
then a list will be returned (if key is a single slice) or a matrix
(if key was a tuple involving a slice).
Examples
========
>>> from sympy import Matrix, I
>>> m = Matrix([
... [1, 2 + I],
... [3, 4 ]])
If the key is a tuple that does not involve a slice then that element
is returned:
>>> m[1, 0]
3
When a tuple key involves a slice, a matrix is returned. Here, the
first column is selected (all rows, column 0):
>>> m[:, 0]
Matrix([
[1],
[3]])
If the slice is not a tuple then it selects from the underlying
list of elements that are arranged in row order and a list is
returned if a slice is involved:
>>> m[0]
1
>>> m[::2]
[1, 3]
"""
if isinstance(key, tuple):
i, j = key
try:
return self._rep.getitem_sympy(index_(i), index_(j))
except (TypeError, IndexError):
if (isinstance(i, Expr) and not i.is_number) or (isinstance(j, Expr) and not j.is_number):
if ((j < 0) is True) or ((j >= self.shape[1]) is True) or\
((i < 0) is True) or ((i >= self.shape[0]) is True):
raise ValueError("index out of boundary")
from sympy.matrices.expressions.matexpr import MatrixElement
return MatrixElement(self, i, j)
if isinstance(i, slice):
i = range(self.rows)[i]
elif is_sequence(i):
pass
else:
i = [i]
if isinstance(j, slice):
j = range(self.cols)[j]
elif is_sequence(j):
pass
else:
j = [j]
return self.extract(i, j)
else:
# Index/slice like a flattened list
rows, cols = self.shape
# Raise the appropriate exception:
if not rows * cols:
return [][key]
rep = self._rep.rep
domain = rep.domain
is_slice = isinstance(key, slice)
if is_slice:
values = [rep.getitem(*divmod(n, cols)) for n in range(rows * cols)[key]]
else:
values = [rep.getitem(*divmod(index_(key), cols))]
if domain != EXRAW:
to_sympy = domain.to_sympy
values = [to_sympy(val) for val in values]
if is_slice:
return values
else:
return values[0]
PK ]ZZZE���Gb Gb sympy/matrices/solvers.pyfrom sympy.core.function import expand_mul
from sympy.core.symbol import Dummy, uniquely_named_symbol, symbols
from sympy.utilities.iterables import numbered_symbols
from .exceptions import ShapeError, NonSquareMatrixError, NonInvertibleMatrixError
from .eigen import _fuzzy_positive_definite
from .utilities import _get_intermediate_simp, _iszero
def _diagonal_solve(M, rhs):
"""Solves ``Ax = B`` efficiently, where A is a diagonal Matrix,
with non-zero diagonal entries.
Examples
========
>>> from sympy import Matrix, eye
>>> A = eye(2)*2
>>> B = Matrix([[1, 2], [3, 4]])
>>> A.diagonal_solve(B) == B/2
True
See Also
========
sympy.matrices.dense.DenseMatrix.lower_triangular_solve
sympy.matrices.dense.DenseMatrix.upper_triangular_solve
gauss_jordan_solve
cholesky_solve
LDLsolve
LUsolve
QRsolve
pinv_solve
cramer_solve
"""
if not M.is_diagonal():
raise TypeError("Matrix should be diagonal")
if rhs.rows != M.rows:
raise TypeError("Size mismatch")
return M._new(
rhs.rows, rhs.cols, lambda i, j: rhs[i, j] / M[i, i])
def _lower_triangular_solve(M, rhs):
"""Solves ``Ax = B``, where A is a lower triangular matrix.
See Also
========
upper_triangular_solve
gauss_jordan_solve
cholesky_solve
diagonal_solve
LDLsolve
LUsolve
QRsolve
pinv_solve
cramer_solve
"""
from .dense import MutableDenseMatrix
if not M.is_square:
raise NonSquareMatrixError("Matrix must be square.")
if rhs.rows != M.rows:
raise ShapeError("Matrices size mismatch.")
if not M.is_lower:
raise ValueError("Matrix must be lower triangular.")
dps = _get_intermediate_simp()
X = MutableDenseMatrix.zeros(M.rows, rhs.cols)
for j in range(rhs.cols):
for i in range(M.rows):
if M[i, i] == 0:
raise TypeError("Matrix must be non-singular.")
X[i, j] = dps((rhs[i, j] - sum(M[i, k]*X[k, j]
for k in range(i))) / M[i, i])
return M._new(X)
def _lower_triangular_solve_sparse(M, rhs):
"""Solves ``Ax = B``, where A is a lower triangular matrix.
See Also
========
upper_triangular_solve
gauss_jordan_solve
cholesky_solve
diagonal_solve
LDLsolve
LUsolve
QRsolve
pinv_solve
cramer_solve
"""
if not M.is_square:
raise NonSquareMatrixError("Matrix must be square.")
if rhs.rows != M.rows:
raise ShapeError("Matrices size mismatch.")
if not M.is_lower:
raise ValueError("Matrix must be lower triangular.")
dps = _get_intermediate_simp()
rows = [[] for i in range(M.rows)]
for i, j, v in M.row_list():
if i > j:
rows[i].append((j, v))
X = rhs.as_mutable()
for j in range(rhs.cols):
for i in range(rhs.rows):
for u, v in rows[i]:
X[i, j] -= v*X[u, j]
X[i, j] = dps(X[i, j] / M[i, i])
return M._new(X)
def _upper_triangular_solve(M, rhs):
"""Solves ``Ax = B``, where A is an upper triangular matrix.
See Also
========
lower_triangular_solve
gauss_jordan_solve
cholesky_solve
diagonal_solve
LDLsolve
LUsolve
QRsolve
pinv_solve
cramer_solve
"""
from .dense import MutableDenseMatrix
if not M.is_square:
raise NonSquareMatrixError("Matrix must be square.")
if rhs.rows != M.rows:
raise ShapeError("Matrix size mismatch.")
if not M.is_upper:
raise TypeError("Matrix is not upper triangular.")
dps = _get_intermediate_simp()
X = MutableDenseMatrix.zeros(M.rows, rhs.cols)
for j in range(rhs.cols):
for i in reversed(range(M.rows)):
if M[i, i] == 0:
raise ValueError("Matrix must be non-singular.")
X[i, j] = dps((rhs[i, j] - sum(M[i, k]*X[k, j]
for k in range(i + 1, M.rows))) / M[i, i])
return M._new(X)
def _upper_triangular_solve_sparse(M, rhs):
"""Solves ``Ax = B``, where A is an upper triangular matrix.
See Also
========
lower_triangular_solve
gauss_jordan_solve
cholesky_solve
diagonal_solve
LDLsolve
LUsolve
QRsolve
pinv_solve
cramer_solve
"""
if not M.is_square:
raise NonSquareMatrixError("Matrix must be square.")
if rhs.rows != M.rows:
raise ShapeError("Matrix size mismatch.")
if not M.is_upper:
raise TypeError("Matrix is not upper triangular.")
dps = _get_intermediate_simp()
rows = [[] for i in range(M.rows)]
for i, j, v in M.row_list():
if i < j:
rows[i].append((j, v))
X = rhs.as_mutable()
for j in range(rhs.cols):
for i in reversed(range(rhs.rows)):
for u, v in reversed(rows[i]):
X[i, j] -= v*X[u, j]
X[i, j] = dps(X[i, j] / M[i, i])
return M._new(X)
def _cholesky_solve(M, rhs):
"""Solves ``Ax = B`` using Cholesky decomposition,
for a general square non-singular matrix.
For a non-square matrix with rows > cols,
the least squares solution is returned.
See Also
========
sympy.matrices.dense.DenseMatrix.lower_triangular_solve
sympy.matrices.dense.DenseMatrix.upper_triangular_solve
gauss_jordan_solve
diagonal_solve
LDLsolve
LUsolve
QRsolve
pinv_solve
cramer_solve
"""
if M.rows < M.cols:
raise NotImplementedError(
'Under-determined System. Try M.gauss_jordan_solve(rhs)')
hermitian = True
reform = False
if M.is_symmetric():
hermitian = False
elif not M.is_hermitian:
reform = True
if reform or _fuzzy_positive_definite(M) is False:
H = M.H
M = H.multiply(M)
rhs = H.multiply(rhs)
hermitian = not M.is_symmetric()
L = M.cholesky(hermitian=hermitian)
Y = L.lower_triangular_solve(rhs)
if hermitian:
return (L.H).upper_triangular_solve(Y)
else:
return (L.T).upper_triangular_solve(Y)
def _LDLsolve(M, rhs):
"""Solves ``Ax = B`` using LDL decomposition,
for a general square and non-singular matrix.
For a non-square matrix with rows > cols,
the least squares solution is returned.
Examples
========
>>> from sympy import Matrix, eye
>>> A = eye(2)*2
>>> B = Matrix([[1, 2], [3, 4]])
>>> A.LDLsolve(B) == B/2
True
See Also
========
sympy.matrices.dense.DenseMatrix.LDLdecomposition
sympy.matrices.dense.DenseMatrix.lower_triangular_solve
sympy.matrices.dense.DenseMatrix.upper_triangular_solve
gauss_jordan_solve
cholesky_solve
diagonal_solve
LUsolve
QRsolve
pinv_solve
cramer_solve
"""
if M.rows < M.cols:
raise NotImplementedError(
'Under-determined System. Try M.gauss_jordan_solve(rhs)')
hermitian = True
reform = False
if M.is_symmetric():
hermitian = False
elif not M.is_hermitian:
reform = True
if reform or _fuzzy_positive_definite(M) is False:
H = M.H
M = H.multiply(M)
rhs = H.multiply(rhs)
hermitian = not M.is_symmetric()
L, D = M.LDLdecomposition(hermitian=hermitian)
Y = L.lower_triangular_solve(rhs)
Z = D.diagonal_solve(Y)
if hermitian:
return (L.H).upper_triangular_solve(Z)
else:
return (L.T).upper_triangular_solve(Z)
def _LUsolve(M, rhs, iszerofunc=_iszero):
"""Solve the linear system ``Ax = rhs`` for ``x`` where ``A = M``.
This is for symbolic matrices, for real or complex ones use
mpmath.lu_solve or mpmath.qr_solve.
See Also
========
sympy.matrices.dense.DenseMatrix.lower_triangular_solve
sympy.matrices.dense.DenseMatrix.upper_triangular_solve
gauss_jordan_solve
cholesky_solve
diagonal_solve
LDLsolve
QRsolve
pinv_solve
LUdecomposition
cramer_solve
"""
if rhs.rows != M.rows:
raise ShapeError(
"``M`` and ``rhs`` must have the same number of rows.")
m = M.rows
n = M.cols
if m < n:
raise NotImplementedError("Underdetermined systems not supported.")
try:
A, perm = M.LUdecomposition_Simple(
iszerofunc=iszerofunc, rankcheck=True)
except ValueError:
raise NonInvertibleMatrixError("Matrix det == 0; not invertible.")
dps = _get_intermediate_simp()
b = rhs.permute_rows(perm).as_mutable()
# forward substitution, all diag entries are scaled to 1
for i in range(m):
for j in range(min(i, n)):
scale = A[i, j]
b.zip_row_op(i, j, lambda x, y: dps(x - y * scale))
# consistency check for overdetermined systems
if m > n:
for i in range(n, m):
for j in range(b.cols):
if not iszerofunc(b[i, j]):
raise ValueError("The system is inconsistent.")
b = b[0:n, :] # truncate zero rows if consistent
# backward substitution
for i in range(n - 1, -1, -1):
for j in range(i + 1, n):
scale = A[i, j]
b.zip_row_op(i, j, lambda x, y: dps(x - y * scale))
scale = A[i, i]
b.row_op(i, lambda x, _: dps(x / scale))
return rhs.__class__(b)
def _QRsolve(M, b):
"""Solve the linear system ``Ax = b``.
``M`` is the matrix ``A``, the method argument is the vector
``b``. The method returns the solution vector ``x``. If ``b`` is a
matrix, the system is solved for each column of ``b`` and the
return value is a matrix of the same shape as ``b``.
This method is slower (approximately by a factor of 2) but
more stable for floating-point arithmetic than the LUsolve method.
However, LUsolve usually uses an exact arithmetic, so you do not need
to use QRsolve.
This is mainly for educational purposes and symbolic matrices, for real
(or complex) matrices use mpmath.qr_solve.
See Also
========
sympy.matrices.dense.DenseMatrix.lower_triangular_solve
sympy.matrices.dense.DenseMatrix.upper_triangular_solve
gauss_jordan_solve
cholesky_solve
diagonal_solve
LDLsolve
LUsolve
pinv_solve
QRdecomposition
cramer_solve
"""
dps = _get_intermediate_simp(expand_mul, expand_mul)
Q, R = M.QRdecomposition()
y = Q.T * b
# back substitution to solve R*x = y:
# We build up the result "backwards" in the vector 'x' and reverse it
# only in the end.
x = []
n = R.rows
for j in range(n - 1, -1, -1):
tmp = y[j, :]
for k in range(j + 1, n):
tmp -= R[j, k] * x[n - 1 - k]
tmp = dps(tmp)
x.append(tmp / R[j, j])
return M.vstack(*x[::-1])
def _gauss_jordan_solve(M, B, freevar=False):
"""
Solves ``Ax = B`` using Gauss Jordan elimination.
There may be zero, one, or infinite solutions. If one solution
exists, it will be returned. If infinite solutions exist, it will
be returned parametrically. If no solutions exist, It will throw
ValueError.
Parameters
==========
B : Matrix
The right hand side of the equation to be solved for. Must have
the same number of rows as matrix A.
freevar : boolean, optional
Flag, when set to `True` will return the indices of the free
variables in the solutions (column Matrix), for a system that is
undetermined (e.g. A has more columns than rows), for which
infinite solutions are possible, in terms of arbitrary
values of free variables. Default `False`.
Returns
=======
x : Matrix
The matrix that will satisfy ``Ax = B``. Will have as many rows as
matrix A has columns, and as many columns as matrix B.
params : Matrix
If the system is underdetermined (e.g. A has more columns than
rows), infinite solutions are possible, in terms of arbitrary
parameters. These arbitrary parameters are returned as params
Matrix.
free_var_index : List, optional
If the system is underdetermined (e.g. A has more columns than
rows), infinite solutions are possible, in terms of arbitrary
values of free variables. Then the indices of the free variables
in the solutions (column Matrix) are returned by free_var_index,
if the flag `freevar` is set to `True`.
Examples
========
>>> from sympy import Matrix
>>> A = Matrix([[1, 2, 1, 1], [1, 2, 2, -1], [2, 4, 0, 6]])
>>> B = Matrix([7, 12, 4])
>>> sol, params = A.gauss_jordan_solve(B)
>>> sol
Matrix([
[-2*tau0 - 3*tau1 + 2],
[ tau0],
[ 2*tau1 + 5],
[ tau1]])
>>> params
Matrix([
[tau0],
[tau1]])
>>> taus_zeroes = { tau:0 for tau in params }
>>> sol_unique = sol.xreplace(taus_zeroes)
>>> sol_unique
Matrix([
[2],
[0],
[5],
[0]])
>>> A = Matrix([[1, 2, 3], [4, 5, 6], [7, 8, 10]])
>>> B = Matrix([3, 6, 9])
>>> sol, params = A.gauss_jordan_solve(B)
>>> sol
Matrix([
[-1],
[ 2],
[ 0]])
>>> params
Matrix(0, 1, [])
>>> A = Matrix([[2, -7], [-1, 4]])
>>> B = Matrix([[-21, 3], [12, -2]])
>>> sol, params = A.gauss_jordan_solve(B)
>>> sol
Matrix([
[0, -2],
[3, -1]])
>>> params
Matrix(0, 2, [])
>>> from sympy import Matrix
>>> A = Matrix([[1, 2, 1, 1], [1, 2, 2, -1], [2, 4, 0, 6]])
>>> B = Matrix([7, 12, 4])
>>> sol, params, freevars = A.gauss_jordan_solve(B, freevar=True)
>>> sol
Matrix([
[-2*tau0 - 3*tau1 + 2],
[ tau0],
[ 2*tau1 + 5],
[ tau1]])
>>> params
Matrix([
[tau0],
[tau1]])
>>> freevars
[1, 3]
See Also
========
sympy.matrices.dense.DenseMatrix.lower_triangular_solve
sympy.matrices.dense.DenseMatrix.upper_triangular_solve
cholesky_solve
diagonal_solve
LDLsolve
LUsolve
QRsolve
pinv
References
==========
.. [1] https://en.wikipedia.org/wiki/Gaussian_elimination
"""
from sympy.matrices import Matrix, zeros
cls = M.__class__
aug = M.hstack(M.copy(), B.copy())
B_cols = B.cols
row, col = aug[:, :-B_cols].shape
# solve by reduced row echelon form
A, pivots = aug.rref(simplify=True)
A, v = A[:, :-B_cols], A[:, -B_cols:]
pivots = list(filter(lambda p: p < col, pivots))
rank = len(pivots)
# Get index of free symbols (free parameters)
# non-pivots columns are free variables
free_var_index = [c for c in range(A.cols) if c not in pivots]
# Bring to block form
permutation = Matrix(pivots + free_var_index).T
# check for existence of solutions
# rank of aug Matrix should be equal to rank of coefficient matrix
if not v[rank:, :].is_zero_matrix:
raise ValueError("Linear system has no solution")
# Free parameters
# what are current unnumbered free symbol names?
name = uniquely_named_symbol('tau', [aug],
compare=lambda i: str(i).rstrip('1234567890'),
modify=lambda s: '_' + s).name
gen = numbered_symbols(name)
tau = Matrix([next(gen) for k in range((col - rank)*B_cols)]).reshape(
col - rank, B_cols)
# Full parametric solution
V = A[:rank, free_var_index]
vt = v[:rank, :]
free_sol = tau.vstack(vt - V * tau, tau)
# Undo permutation
sol = zeros(col, B_cols)
for k in range(col):
sol[permutation[k], :] = free_sol[k,:]
sol, tau = cls(sol), cls(tau)
if freevar:
return sol, tau, free_var_index
else:
return sol, tau
def _pinv_solve(M, B, arbitrary_matrix=None):
"""Solve ``Ax = B`` using the Moore-Penrose pseudoinverse.
There may be zero, one, or infinite solutions. If one solution
exists, it will be returned. If infinite solutions exist, one will
be returned based on the value of arbitrary_matrix. If no solutions
exist, the least-squares solution is returned.
Parameters
==========
B : Matrix
The right hand side of the equation to be solved for. Must have
the same number of rows as matrix A.
arbitrary_matrix : Matrix
If the system is underdetermined (e.g. A has more columns than
rows), infinite solutions are possible, in terms of an arbitrary
matrix. This parameter may be set to a specific matrix to use
for that purpose; if so, it must be the same shape as x, with as
many rows as matrix A has columns, and as many columns as matrix
B. If left as None, an appropriate matrix containing dummy
symbols in the form of ``wn_m`` will be used, with n and m being
row and column position of each symbol.
Returns
=======
x : Matrix
The matrix that will satisfy ``Ax = B``. Will have as many rows as
matrix A has columns, and as many columns as matrix B.
Examples
========
>>> from sympy import Matrix
>>> A = Matrix([[1, 2, 3], [4, 5, 6]])
>>> B = Matrix([7, 8])
>>> A.pinv_solve(B)
Matrix([
[ _w0_0/6 - _w1_0/3 + _w2_0/6 - 55/18],
[-_w0_0/3 + 2*_w1_0/3 - _w2_0/3 + 1/9],
[ _w0_0/6 - _w1_0/3 + _w2_0/6 + 59/18]])
>>> A.pinv_solve(B, arbitrary_matrix=Matrix([0, 0, 0]))
Matrix([
[-55/18],
[ 1/9],
[ 59/18]])
See Also
========
sympy.matrices.dense.DenseMatrix.lower_triangular_solve
sympy.matrices.dense.DenseMatrix.upper_triangular_solve
gauss_jordan_solve
cholesky_solve
diagonal_solve
LDLsolve
LUsolve
QRsolve
pinv
Notes
=====
This may return either exact solutions or least squares solutions.
To determine which, check ``A * A.pinv() * B == B``. It will be
True if exact solutions exist, and False if only a least-squares
solution exists. Be aware that the left hand side of that equation
may need to be simplified to correctly compare to the right hand
side.
References
==========
.. [1] https://en.wikipedia.org/wiki/Moore-Penrose_pseudoinverse#Obtaining_all_solutions_of_a_linear_system
"""
from sympy.matrices import eye
A = M
A_pinv = M.pinv()
if arbitrary_matrix is None:
rows, cols = A.cols, B.cols
w = symbols('w:{}_:{}'.format(rows, cols), cls=Dummy)
arbitrary_matrix = M.__class__(cols, rows, w).T
return A_pinv.multiply(B) + (eye(A.cols) -
A_pinv.multiply(A)).multiply(arbitrary_matrix)
def _cramer_solve(M, rhs, det_method="laplace"):
"""Solves system of linear equations using Cramer's rule.
This method is relatively inefficient compared to other methods.
However it only uses a single division, assuming a division-free determinant
method is provided. This is helpful to minimize the chance of divide-by-zero
cases in symbolic solutions to linear systems.
Parameters
==========
M : Matrix
The matrix representing the left hand side of the equation.
rhs : Matrix
The matrix representing the right hand side of the equation.
det_method : str or callable
The method to use to calculate the determinant of the matrix.
The default is ``'laplace'``. If a callable is passed, it should take a
single argument, the matrix, and return the determinant of the matrix.
Returns
=======
x : Matrix
The matrix that will satisfy ``Ax = B``. Will have as many rows as
matrix A has columns, and as many columns as matrix B.
Examples
========
>>> from sympy import Matrix
>>> A = Matrix([[0, -6, 1], [0, -6, -1], [-5, -2, 3]])
>>> B = Matrix([[-30, -9], [-18, -27], [-26, 46]])
>>> x = A.cramer_solve(B)
>>> x
Matrix([
[ 0, -5],
[ 4, 3],
[-6, 9]])
References
==========
.. [1] https://en.wikipedia.org/wiki/Cramer%27s_rule#Explicit_formulas_for_small_systems
"""
from .dense import zeros
def entry(i, j):
return rhs[i, sol] if j == col else M[i, j]
if det_method == "bird":
from .determinant import _det_bird
det = _det_bird
elif det_method == "laplace":
from .determinant import _det_laplace
det = _det_laplace
elif isinstance(det_method, str):
det = lambda matrix: matrix.det(method=det_method)
else:
det = det_method
det_M = det(M)
x = zeros(*rhs.shape)
for sol in range(rhs.shape[1]):
for col in range(rhs.shape[0]):
x[col, sol] = det(M.__class__(*M.shape, entry)) / det_M
return M.__class__(x)
def _solve(M, rhs, method='GJ'):
"""Solves linear equation where the unique solution exists.
Parameters
==========
rhs : Matrix
Vector representing the right hand side of the linear equation.
method : string, optional
If set to ``'GJ'`` or ``'GE'``, the Gauss-Jordan elimination will be
used, which is implemented in the routine ``gauss_jordan_solve``.
If set to ``'LU'``, ``LUsolve`` routine will be used.
If set to ``'QR'``, ``QRsolve`` routine will be used.
If set to ``'PINV'``, ``pinv_solve`` routine will be used.
If set to ``'CRAMER'``, ``cramer_solve`` routine will be used.
It also supports the methods available for special linear systems
For positive definite systems:
If set to ``'CH'``, ``cholesky_solve`` routine will be used.
If set to ``'LDL'``, ``LDLsolve`` routine will be used.
To use a different method and to compute the solution via the
inverse, use a method defined in the .inv() docstring.
Returns
=======
solutions : Matrix
Vector representing the solution.
Raises
======
ValueError
If there is not a unique solution then a ``ValueError`` will be
raised.
If ``M`` is not square, a ``ValueError`` and a different routine
for solving the system will be suggested.
"""
if method in ('GJ', 'GE'):
try:
soln, param = M.gauss_jordan_solve(rhs)
if param:
raise NonInvertibleMatrixError("Matrix det == 0; not invertible. "
"Try ``M.gauss_jordan_solve(rhs)`` to obtain a parametric solution.")
except ValueError:
raise NonInvertibleMatrixError("Matrix det == 0; not invertible.")
return soln
elif method == 'LU':
return M.LUsolve(rhs)
elif method == 'CH':
return M.cholesky_solve(rhs)
elif method == 'QR':
return M.QRsolve(rhs)
elif method == 'LDL':
return M.LDLsolve(rhs)
elif method == 'PINV':
return M.pinv_solve(rhs)
elif method == 'CRAMER':
return M.cramer_solve(rhs)
else:
return M.inv(method=method).multiply(rhs)
def _solve_least_squares(M, rhs, method='CH'):
"""Return the least-square fit to the data.
Parameters
==========
rhs : Matrix
Vector representing the right hand side of the linear equation.
method : string or boolean, optional
If set to ``'CH'``, ``cholesky_solve`` routine will be used.
If set to ``'LDL'``, ``LDLsolve`` routine will be used.
If set to ``'QR'``, ``QRsolve`` routine will be used.
If set to ``'PINV'``, ``pinv_solve`` routine will be used.
Otherwise, the conjugate of ``M`` will be used to create a system
of equations that is passed to ``solve`` along with the hint
defined by ``method``.
Returns
=======
solutions : Matrix
Vector representing the solution.
Examples
========
>>> from sympy import Matrix, ones
>>> A = Matrix([1, 2, 3])
>>> B = Matrix([2, 3, 4])
>>> S = Matrix(A.row_join(B))
>>> S
Matrix([
[1, 2],
[2, 3],
[3, 4]])
If each line of S represent coefficients of Ax + By
and x and y are [2, 3] then S*xy is:
>>> r = S*Matrix([2, 3]); r
Matrix([
[ 8],
[13],
[18]])
But let's add 1 to the middle value and then solve for the
least-squares value of xy:
>>> xy = S.solve_least_squares(Matrix([8, 14, 18])); xy
Matrix([
[ 5/3],
[10/3]])
The error is given by S*xy - r:
>>> S*xy - r
Matrix([
[1/3],
[1/3],
[1/3]])
>>> _.norm().n(2)
0.58
If a different xy is used, the norm will be higher:
>>> xy += ones(2, 1)/10
>>> (S*xy - r).norm().n(2)
1.5
"""
if method == 'CH':
return M.cholesky_solve(rhs)
elif method == 'QR':
return M.QRsolve(rhs)
elif method == 'LDL':
return M.LDLsolve(rhs)
elif method == 'PINV':
return M.pinv_solve(rhs)
else:
t = M.H
return (t * M).solve(t * rhs, method=method)
PK ]ZZZ5���Q9 Q9 sympy/matrices/sparse.pyfrom collections.abc import Callable
from sympy.core.containers import Dict
from sympy.utilities.exceptions import sympy_deprecation_warning
from sympy.utilities.iterables import is_sequence
from sympy.utilities.misc import as_int
from .matrixbase import MatrixBase
from .repmatrix import MutableRepMatrix, RepMatrix
from .utilities import _iszero
from .decompositions import (
_liupc, _row_structure_symbolic_cholesky, _cholesky_sparse,
_LDLdecomposition_sparse)
from .solvers import (
_lower_triangular_solve_sparse, _upper_triangular_solve_sparse)
class SparseRepMatrix(RepMatrix):
"""
A sparse matrix (a matrix with a large number of zero elements).
Examples
========
>>> from sympy import SparseMatrix, ones
>>> SparseMatrix(2, 2, range(4))
Matrix([
[0, 1],
[2, 3]])
>>> SparseMatrix(2, 2, {(1, 1): 2})
Matrix([
[0, 0],
[0, 2]])
A SparseMatrix can be instantiated from a ragged list of lists:
>>> SparseMatrix([[1, 2, 3], [1, 2], [1]])
Matrix([
[1, 2, 3],
[1, 2, 0],
[1, 0, 0]])
For safety, one may include the expected size and then an error
will be raised if the indices of any element are out of range or
(for a flat list) if the total number of elements does not match
the expected shape:
>>> SparseMatrix(2, 2, [1, 2])
Traceback (most recent call last):
...
ValueError: List length (2) != rows*columns (4)
Here, an error is not raised because the list is not flat and no
element is out of range:
>>> SparseMatrix(2, 2, [[1, 2]])
Matrix([
[1, 2],
[0, 0]])
But adding another element to the first (and only) row will cause
an error to be raised:
>>> SparseMatrix(2, 2, [[1, 2, 3]])
Traceback (most recent call last):
...
ValueError: The location (0, 2) is out of designated range: (1, 1)
To autosize the matrix, pass None for rows:
>>> SparseMatrix(None, [[1, 2, 3]])
Matrix([[1, 2, 3]])
>>> SparseMatrix(None, {(1, 1): 1, (3, 3): 3})
Matrix([
[0, 0, 0, 0],
[0, 1, 0, 0],
[0, 0, 0, 0],
[0, 0, 0, 3]])
Values that are themselves a Matrix are automatically expanded:
>>> SparseMatrix(4, 4, {(1, 1): ones(2)})
Matrix([
[0, 0, 0, 0],
[0, 1, 1, 0],
[0, 1, 1, 0],
[0, 0, 0, 0]])
A ValueError is raised if the expanding matrix tries to overwrite
a different element already present:
>>> SparseMatrix(3, 3, {(0, 0): ones(2), (1, 1): 2})
Traceback (most recent call last):
...
ValueError: collision at (1, 1)
See Also
========
DenseMatrix
MutableSparseMatrix
ImmutableSparseMatrix
"""
@classmethod
def _handle_creation_inputs(cls, *args, **kwargs):
if len(args) == 1 and isinstance(args[0], MatrixBase):
rows = args[0].rows
cols = args[0].cols
smat = args[0].todok()
return rows, cols, smat
smat = {}
# autosizing
if len(args) == 2 and args[0] is None:
args = [None, None, args[1]]
if len(args) == 3:
r, c = args[:2]
if r is c is None:
rows = cols = None
elif None in (r, c):
raise ValueError(
'Pass rows=None and no cols for autosizing.')
else:
rows, cols = as_int(args[0]), as_int(args[1])
if isinstance(args[2], Callable):
op = args[2]
if None in (rows, cols):
raise ValueError(
"{} and {} must be integers for this "
"specification.".format(rows, cols))
row_indices = [cls._sympify(i) for i in range(rows)]
col_indices = [cls._sympify(j) for j in range(cols)]
for i in row_indices:
for j in col_indices:
value = cls._sympify(op(i, j))
if value != cls.zero:
smat[i, j] = value
return rows, cols, smat
elif isinstance(args[2], (dict, Dict)):
def update(i, j, v):
# update smat and make sure there are no collisions
if v:
if (i, j) in smat and v != smat[i, j]:
raise ValueError(
"There is a collision at {} for {} and {}."
.format((i, j), v, smat[i, j])
)
smat[i, j] = v
# manual copy, copy.deepcopy() doesn't work
for (r, c), v in args[2].items():
if isinstance(v, MatrixBase):
for (i, j), vv in v.todok().items():
update(r + i, c + j, vv)
elif isinstance(v, (list, tuple)):
_, _, smat = cls._handle_creation_inputs(v, **kwargs)
for i, j in smat:
update(r + i, c + j, smat[i, j])
else:
v = cls._sympify(v)
update(r, c, cls._sympify(v))
elif is_sequence(args[2]):
flat = not any(is_sequence(i) for i in args[2])
if not flat:
_, _, smat = \
cls._handle_creation_inputs(args[2], **kwargs)
else:
flat_list = args[2]
if len(flat_list) != rows * cols:
raise ValueError(
"The length of the flat list ({}) does not "
"match the specified size ({} * {})."
.format(len(flat_list), rows, cols)
)
for i in range(rows):
for j in range(cols):
value = flat_list[i*cols + j]
value = cls._sympify(value)
if value != cls.zero:
smat[i, j] = value
if rows is None: # autosizing
keys = smat.keys()
rows = max(r for r, _ in keys) + 1 if keys else 0
cols = max(c for _, c in keys) + 1 if keys else 0
else:
for i, j in smat.keys():
if i and i >= rows or j and j >= cols:
raise ValueError(
"The location {} is out of the designated range"
"[{}, {}]x[{}, {}]"
.format((i, j), 0, rows - 1, 0, cols - 1)
)
return rows, cols, smat
elif len(args) == 1 and isinstance(args[0], (list, tuple)):
# list of values or lists
v = args[0]
c = 0
for i, row in enumerate(v):
if not isinstance(row, (list, tuple)):
row = [row]
for j, vv in enumerate(row):
if vv != cls.zero:
smat[i, j] = cls._sympify(vv)
c = max(c, len(row))
rows = len(v) if c else 0
cols = c
return rows, cols, smat
else:
# handle full matrix forms with _handle_creation_inputs
rows, cols, mat = super()._handle_creation_inputs(*args)
for i in range(rows):
for j in range(cols):
value = mat[cols*i + j]
if value != cls.zero:
smat[i, j] = value
return rows, cols, smat
@property
def _smat(self):
sympy_deprecation_warning(
"""
The private _smat attribute of SparseMatrix is deprecated. Use the
.todok() method instead.
""",
deprecated_since_version="1.9",
active_deprecations_target="deprecated-private-matrix-attributes"
)
return self.todok()
def _eval_inverse(self, **kwargs):
return self.inv(method=kwargs.get('method', 'LDL'),
iszerofunc=kwargs.get('iszerofunc', _iszero),
try_block_diag=kwargs.get('try_block_diag', False))
def applyfunc(self, f):
"""Apply a function to each element of the matrix.
Examples
========
>>> from sympy import SparseMatrix
>>> m = SparseMatrix(2, 2, lambda i, j: i*2+j)
>>> m
Matrix([
[0, 1],
[2, 3]])
>>> m.applyfunc(lambda i: 2*i)
Matrix([
[0, 2],
[4, 6]])
"""
if not callable(f):
raise TypeError("`f` must be callable.")
# XXX: This only applies the function to the nonzero elements of the
# matrix so is inconsistent with DenseMatrix.applyfunc e.g.
# zeros(2, 2).applyfunc(lambda x: x + 1)
dok = {}
for k, v in self.todok().items():
fv = f(v)
if fv != 0:
dok[k] = fv
return self._new(self.rows, self.cols, dok)
def as_immutable(self):
"""Returns an Immutable version of this Matrix."""
from .immutable import ImmutableSparseMatrix
return ImmutableSparseMatrix(self)
def as_mutable(self):
"""Returns a mutable version of this matrix.
Examples
========
>>> from sympy import ImmutableMatrix
>>> X = ImmutableMatrix([[1, 2], [3, 4]])
>>> Y = X.as_mutable()
>>> Y[1, 1] = 5 # Can set values in Y
>>> Y
Matrix([
[1, 2],
[3, 5]])
"""
return MutableSparseMatrix(self)
def col_list(self):
"""Returns a column-sorted list of non-zero elements of the matrix.
Examples
========
>>> from sympy import SparseMatrix
>>> a=SparseMatrix(((1, 2), (3, 4)))
>>> a
Matrix([
[1, 2],
[3, 4]])
>>> a.CL
[(0, 0, 1), (1, 0, 3), (0, 1, 2), (1, 1, 4)]
See Also
========
sympy.matrices.sparse.SparseMatrix.row_list
"""
return [tuple(k + (self[k],)) for k in sorted(self.todok().keys(), key=lambda k: list(reversed(k)))]
def nnz(self):
"""Returns the number of non-zero elements in Matrix."""
return len(self.todok())
def row_list(self):
"""Returns a row-sorted list of non-zero elements of the matrix.
Examples
========
>>> from sympy import SparseMatrix
>>> a = SparseMatrix(((1, 2), (3, 4)))
>>> a
Matrix([
[1, 2],
[3, 4]])
>>> a.RL
[(0, 0, 1), (0, 1, 2), (1, 0, 3), (1, 1, 4)]
See Also
========
sympy.matrices.sparse.SparseMatrix.col_list
"""
return [tuple(k + (self[k],)) for k in
sorted(self.todok().keys(), key=list)]
def scalar_multiply(self, scalar):
"Scalar element-wise multiplication"
return scalar * self
def solve_least_squares(self, rhs, method='LDL'):
"""Return the least-square fit to the data.
By default the cholesky_solve routine is used (method='CH'); other
methods of matrix inversion can be used. To find out which are
available, see the docstring of the .inv() method.
Examples
========
>>> from sympy import SparseMatrix, Matrix, ones
>>> A = Matrix([1, 2, 3])
>>> B = Matrix([2, 3, 4])
>>> S = SparseMatrix(A.row_join(B))
>>> S
Matrix([
[1, 2],
[2, 3],
[3, 4]])
If each line of S represent coefficients of Ax + By
and x and y are [2, 3] then S*xy is:
>>> r = S*Matrix([2, 3]); r
Matrix([
[ 8],
[13],
[18]])
But let's add 1 to the middle value and then solve for the
least-squares value of xy:
>>> xy = S.solve_least_squares(Matrix([8, 14, 18])); xy
Matrix([
[ 5/3],
[10/3]])
The error is given by S*xy - r:
>>> S*xy - r
Matrix([
[1/3],
[1/3],
[1/3]])
>>> _.norm().n(2)
0.58
If a different xy is used, the norm will be higher:
>>> xy += ones(2, 1)/10
>>> (S*xy - r).norm().n(2)
1.5
"""
t = self.T
return (t*self).inv(method=method)*t*rhs
def solve(self, rhs, method='LDL'):
"""Return solution to self*soln = rhs using given inversion method.
For a list of possible inversion methods, see the .inv() docstring.
"""
if not self.is_square:
if self.rows < self.cols:
raise ValueError('Under-determined system.')
elif self.rows > self.cols:
raise ValueError('For over-determined system, M, having '
'more rows than columns, try M.solve_least_squares(rhs).')
else:
return self.inv(method=method).multiply(rhs)
RL = property(row_list, None, None, "Alternate faster representation")
CL = property(col_list, None, None, "Alternate faster representation")
def liupc(self):
return _liupc(self)
def row_structure_symbolic_cholesky(self):
return _row_structure_symbolic_cholesky(self)
def cholesky(self, hermitian=True):
return _cholesky_sparse(self, hermitian=hermitian)
def LDLdecomposition(self, hermitian=True):
return _LDLdecomposition_sparse(self, hermitian=hermitian)
def lower_triangular_solve(self, rhs):
return _lower_triangular_solve_sparse(self, rhs)
def upper_triangular_solve(self, rhs):
return _upper_triangular_solve_sparse(self, rhs)
liupc.__doc__ = _liupc.__doc__
row_structure_symbolic_cholesky.__doc__ = _row_structure_symbolic_cholesky.__doc__
cholesky.__doc__ = _cholesky_sparse.__doc__
LDLdecomposition.__doc__ = _LDLdecomposition_sparse.__doc__
lower_triangular_solve.__doc__ = lower_triangular_solve.__doc__
upper_triangular_solve.__doc__ = upper_triangular_solve.__doc__
class MutableSparseMatrix(SparseRepMatrix, MutableRepMatrix):
@classmethod
def _new(cls, *args, **kwargs):
rows, cols, smat = cls._handle_creation_inputs(*args, **kwargs)
rep = cls._smat_to_DomainMatrix(rows, cols, smat)
return cls._fromrep(rep)
SparseMatrix = MutableSparseMatrix
PK ]ZZZ7����# �# sympy/matrices/sparsetools.pyfrom sympy.core.containers import Dict
from sympy.core.symbol import Dummy
from sympy.utilities.iterables import is_sequence
from sympy.utilities.misc import as_int, filldedent
from .sparse import MutableSparseMatrix as SparseMatrix
def _doktocsr(dok):
"""Converts a sparse matrix to Compressed Sparse Row (CSR) format.
Parameters
==========
A : contains non-zero elements sorted by key (row, column)
JA : JA[i] is the column corresponding to A[i]
IA : IA[i] contains the index in A for the first non-zero element
of row[i]. Thus IA[i+1] - IA[i] gives number of non-zero
elements row[i]. The length of IA is always 1 more than the
number of rows in the matrix.
Examples
========
>>> from sympy.matrices.sparsetools import _doktocsr
>>> from sympy import SparseMatrix, diag
>>> m = SparseMatrix(diag(1, 2, 3))
>>> m[2, 0] = -1
>>> _doktocsr(m)
[[1, 2, -1, 3], [0, 1, 0, 2], [0, 1, 2, 4], [3, 3]]
"""
row, JA, A = [list(i) for i in zip(*dok.row_list())]
IA = [0]*((row[0] if row else 0) + 1)
for i, r in enumerate(row):
IA.extend([i]*(r - row[i - 1])) # if i = 0 nothing is extended
IA.extend([len(A)]*(dok.rows - len(IA) + 1))
shape = [dok.rows, dok.cols]
return [A, JA, IA, shape]
def _csrtodok(csr):
"""Converts a CSR representation to DOK representation.
Examples
========
>>> from sympy.matrices.sparsetools import _csrtodok
>>> _csrtodok([[5, 8, 3, 6], [0, 1, 2, 1], [0, 0, 2, 3, 4], [4, 3]])
Matrix([
[0, 0, 0],
[5, 8, 0],
[0, 0, 3],
[0, 6, 0]])
"""
smat = {}
A, JA, IA, shape = csr
for i in range(len(IA) - 1):
indices = slice(IA[i], IA[i + 1])
for l, m in zip(A[indices], JA[indices]):
smat[i, m] = l
return SparseMatrix(*shape, smat)
def banded(*args, **kwargs):
"""Returns a SparseMatrix from the given dictionary describing
the diagonals of the matrix. The keys are positive for upper
diagonals and negative for those below the main diagonal. The
values may be:
* expressions or single-argument functions,
* lists or tuples of values,
* matrices
Unless dimensions are given, the size of the returned matrix will
be large enough to contain the largest non-zero value provided.
kwargs
======
rows : rows of the resulting matrix; computed if
not given.
cols : columns of the resulting matrix; computed if
not given.
Examples
========
>>> from sympy import banded, ones, Matrix
>>> from sympy.abc import x
If explicit values are given in tuples,
the matrix will autosize to contain all values, otherwise
a single value is filled onto the entire diagonal:
>>> banded({1: (1, 2, 3), -1: (4, 5, 6), 0: x})
Matrix([
[x, 1, 0, 0],
[4, x, 2, 0],
[0, 5, x, 3],
[0, 0, 6, x]])
A function accepting a single argument can be used to fill the
diagonal as a function of diagonal index (which starts at 0).
The size (or shape) of the matrix must be given to obtain more
than a 1x1 matrix:
>>> s = lambda d: (1 + d)**2
>>> banded(5, {0: s, 2: s, -2: 2})
Matrix([
[1, 0, 1, 0, 0],
[0, 4, 0, 4, 0],
[2, 0, 9, 0, 9],
[0, 2, 0, 16, 0],
[0, 0, 2, 0, 25]])
The diagonal of matrices placed on a diagonal will coincide
with the indicated diagonal:
>>> vert = Matrix([1, 2, 3])
>>> banded({0: vert}, cols=3)
Matrix([
[1, 0, 0],
[2, 1, 0],
[3, 2, 1],
[0, 3, 2],
[0, 0, 3]])
>>> banded(4, {0: ones(2)})
Matrix([
[1, 1, 0, 0],
[1, 1, 0, 0],
[0, 0, 1, 1],
[0, 0, 1, 1]])
Errors are raised if the designated size will not hold
all values an integral number of times. Here, the rows
are designated as odd (but an even number is required to
hold the off-diagonal 2x2 ones):
>>> banded({0: 2, 1: ones(2)}, rows=5)
Traceback (most recent call last):
...
ValueError:
sequence does not fit an integral number of times in the matrix
And here, an even number of rows is given...but the square
matrix has an even number of columns, too. As we saw
in the previous example, an odd number is required:
>>> banded(4, {0: 2, 1: ones(2)}) # trying to make 4x4 and cols must be odd
Traceback (most recent call last):
...
ValueError:
sequence does not fit an integral number of times in the matrix
A way around having to count rows is to enclosing matrix elements
in a tuple and indicate the desired number of them to the right:
>>> banded({0: 2, 2: (ones(2),)*3})
Matrix([
[2, 0, 1, 1, 0, 0, 0, 0],
[0, 2, 1, 1, 0, 0, 0, 0],
[0, 0, 2, 0, 1, 1, 0, 0],
[0, 0, 0, 2, 1, 1, 0, 0],
[0, 0, 0, 0, 2, 0, 1, 1],
[0, 0, 0, 0, 0, 2, 1, 1]])
An error will be raised if more than one value
is written to a given entry. Here, the ones overlap
with the main diagonal if they are placed on the
first diagonal:
>>> banded({0: (2,)*5, 1: (ones(2),)*3})
Traceback (most recent call last):
...
ValueError: collision at (1, 1)
By placing a 0 at the bottom left of the 2x2 matrix of
ones, the collision is avoided:
>>> u2 = Matrix([
... [1, 1],
... [0, 1]])
>>> banded({0: [2]*5, 1: [u2]*3})
Matrix([
[2, 1, 1, 0, 0, 0, 0],
[0, 2, 1, 0, 0, 0, 0],
[0, 0, 2, 1, 1, 0, 0],
[0, 0, 0, 2, 1, 0, 0],
[0, 0, 0, 0, 2, 1, 1],
[0, 0, 0, 0, 0, 0, 1]])
"""
try:
if len(args) not in (1, 2, 3):
raise TypeError
if not isinstance(args[-1], (dict, Dict)):
raise TypeError
if len(args) == 1:
rows = kwargs.get('rows', None)
cols = kwargs.get('cols', None)
if rows is not None:
rows = as_int(rows)
if cols is not None:
cols = as_int(cols)
elif len(args) == 2:
rows = cols = as_int(args[0])
else:
rows, cols = map(as_int, args[:2])
# fails with ValueError if any keys are not ints
_ = all(as_int(k) for k in args[-1])
except (ValueError, TypeError):
raise TypeError(filldedent(
'''unrecognized input to banded:
expecting [[row,] col,] {int: value}'''))
def rc(d):
# return row,col coord of diagonal start
r = -d if d < 0 else 0
c = 0 if r else d
return r, c
smat = {}
undone = []
tba = Dummy()
# first handle objects with size
for d, v in args[-1].items():
r, c = rc(d)
# note: only list and tuple are recognized since this
# will allow other Basic objects like Tuple
# into the matrix if so desired
if isinstance(v, (list, tuple)):
extra = 0
for i, vi in enumerate(v):
i += extra
if is_sequence(vi):
vi = SparseMatrix(vi)
smat[r + i, c + i] = vi
extra += min(vi.shape) - 1
else:
smat[r + i, c + i] = vi
elif is_sequence(v):
v = SparseMatrix(v)
rv, cv = v.shape
if rows and cols:
nr, xr = divmod(rows - r, rv)
nc, xc = divmod(cols - c, cv)
x = xr or xc
do = min(nr, nc)
elif rows:
do, x = divmod(rows - r, rv)
elif cols:
do, x = divmod(cols - c, cv)
else:
do = 1
x = 0
if x:
raise ValueError(filldedent('''
sequence does not fit an integral number of times
in the matrix'''))
j = min(v.shape)
for i in range(do):
smat[r, c] = v
r += j
c += j
elif v:
smat[r, c] = tba
undone.append((d, v))
s = SparseMatrix(None, smat) # to expand matrices
smat = s.todok()
# check for dim errors here
if rows is not None and rows < s.rows:
raise ValueError('Designated rows %s < needed %s' % (rows, s.rows))
if cols is not None and cols < s.cols:
raise ValueError('Designated cols %s < needed %s' % (cols, s.cols))
if rows is cols is None:
rows = s.rows
cols = s.cols
elif rows is not None and cols is None:
cols = max(rows, s.cols)
elif cols is not None and rows is None:
rows = max(cols, s.rows)
def update(i, j, v):
# update smat and make sure there are
# no collisions
if v:
if (i, j) in smat and smat[i, j] not in (tba, v):
raise ValueError('collision at %s' % ((i, j),))
smat[i, j] = v
if undone:
for d, vi in undone:
r, c = rc(d)
v = vi if callable(vi) else lambda _: vi
i = 0
while r + i < rows and c + i < cols:
update(r + i, c + i, v(i))
i += 1
return SparseMatrix(rows, cols, smat)
PK ]ZZZ|]��� � sympy/matrices/subspaces.pyfrom .utilities import _iszero
def _columnspace(M, simplify=False):
"""Returns a list of vectors (Matrix objects) that span columnspace of ``M``
Examples
========
>>> from sympy import Matrix
>>> M = Matrix(3, 3, [1, 3, 0, -2, -6, 0, 3, 9, 6])
>>> M
Matrix([
[ 1, 3, 0],
[-2, -6, 0],
[ 3, 9, 6]])
>>> M.columnspace()
[Matrix([
[ 1],
[-2],
[ 3]]), Matrix([
[0],
[0],
[6]])]
See Also
========
nullspace
rowspace
"""
reduced, pivots = M.echelon_form(simplify=simplify, with_pivots=True)
return [M.col(i) for i in pivots]
def _nullspace(M, simplify=False, iszerofunc=_iszero):
"""Returns list of vectors (Matrix objects) that span nullspace of ``M``
Examples
========
>>> from sympy import Matrix
>>> M = Matrix(3, 3, [1, 3, 0, -2, -6, 0, 3, 9, 6])
>>> M
Matrix([
[ 1, 3, 0],
[-2, -6, 0],
[ 3, 9, 6]])
>>> M.nullspace()
[Matrix([
[-3],
[ 1],
[ 0]])]
See Also
========
columnspace
rowspace
"""
reduced, pivots = M.rref(iszerofunc=iszerofunc, simplify=simplify)
free_vars = [i for i in range(M.cols) if i not in pivots]
basis = []
for free_var in free_vars:
# for each free variable, we will set it to 1 and all others
# to 0. Then, we will use back substitution to solve the system
vec = [M.zero] * M.cols
vec[free_var] = M.one
for piv_row, piv_col in enumerate(pivots):
vec[piv_col] -= reduced[piv_row, free_var]
basis.append(vec)
return [M._new(M.cols, 1, b) for b in basis]
def _rowspace(M, simplify=False):
"""Returns a list of vectors that span the row space of ``M``.
Examples
========
>>> from sympy import Matrix
>>> M = Matrix(3, 3, [1, 3, 0, -2, -6, 0, 3, 9, 6])
>>> M
Matrix([
[ 1, 3, 0],
[-2, -6, 0],
[ 3, 9, 6]])
>>> M.rowspace()
[Matrix([[1, 3, 0]]), Matrix([[0, 0, 6]])]
"""
reduced, pivots = M.echelon_form(simplify=simplify, with_pivots=True)
return [reduced.row(i) for i in range(len(pivots))]
def _orthogonalize(cls, *vecs, normalize=False, rankcheck=False):
"""Apply the Gram-Schmidt orthogonalization procedure
to vectors supplied in ``vecs``.
Parameters
==========
vecs
vectors to be made orthogonal
normalize : bool
If ``True``, return an orthonormal basis.
rankcheck : bool
If ``True``, the computation does not stop when encountering
linearly dependent vectors.
If ``False``, it will raise ``ValueError`` when any zero
or linearly dependent vectors are found.
Returns
=======
list
List of orthogonal (or orthonormal) basis vectors.
Examples
========
>>> from sympy import I, Matrix
>>> v = [Matrix([1, I]), Matrix([1, -I])]
>>> Matrix.orthogonalize(*v)
[Matrix([
[1],
[I]]), Matrix([
[ 1],
[-I]])]
See Also
========
MatrixBase.QRdecomposition
References
==========
.. [1] https://en.wikipedia.org/wiki/Gram%E2%80%93Schmidt_process
"""
from .decompositions import _QRdecomposition_optional
if not vecs:
return []
all_row_vecs = (vecs[0].rows == 1)
vecs = [x.vec() for x in vecs]
M = cls.hstack(*vecs)
Q, R = _QRdecomposition_optional(M, normalize=normalize)
if rankcheck and Q.cols < len(vecs):
raise ValueError("GramSchmidt: vector set not linearly independent")
ret = []
for i in range(Q.cols):
if all_row_vecs:
col = cls(Q[:, i].T)
else:
col = cls(Q[:, i])
ret.append(col)
return ret
PK ]ZZZ�X��E E sympy/matrices/utilities.pyfrom contextlib import contextmanager
from threading import local
from sympy.core.function import expand_mul
class DotProdSimpState(local):
def __init__(self):
self.state = None
_dotprodsimp_state = DotProdSimpState()
@contextmanager
def dotprodsimp(x):
old = _dotprodsimp_state.state
try:
_dotprodsimp_state.state = x
yield
finally:
_dotprodsimp_state.state = old
def _dotprodsimp(expr, withsimp=False):
"""Wrapper for simplify.dotprodsimp to avoid circular imports."""
from sympy.simplify.simplify import dotprodsimp as dps
return dps(expr, withsimp=withsimp)
def _get_intermediate_simp(deffunc=lambda x: x, offfunc=lambda x: x,
onfunc=_dotprodsimp, dotprodsimp=None):
"""Support function for controlling intermediate simplification. Returns a
simplification function according to the global setting of dotprodsimp
operation.
``deffunc`` - Function to be used by default.
``offfunc`` - Function to be used if dotprodsimp has been turned off.
``onfunc`` - Function to be used if dotprodsimp has been turned on.
``dotprodsimp`` - True, False or None. Will be overridden by global
_dotprodsimp_state.state if that is not None.
"""
if dotprodsimp is False or _dotprodsimp_state.state is False:
return offfunc
if dotprodsimp is True or _dotprodsimp_state.state is True:
return onfunc
return deffunc # None, None
def _get_intermediate_simp_bool(default=False, dotprodsimp=None):
"""Same as ``_get_intermediate_simp`` but returns bools instead of functions
by default."""
return _get_intermediate_simp(default, False, True, dotprodsimp)
def _iszero(x):
"""Returns True if x is zero."""
return getattr(x, 'is_zero', None)
def _is_zero_after_expand_mul(x):
"""Tests by expand_mul only, suitable for polynomials and rational
functions."""
return expand_mul(x) == 0
def _simplify(expr):
""" Wrapper to avoid circular imports. """
from sympy.simplify.simplify import simplify
return simplify(expr)
PK ]ZZZ % sympy/matrices/benchmarks/__init__.pyPK ]ZZZ��F�2 2 ) sympy/matrices/benchmarks/bench_matrix.pyfrom sympy.core.numbers import Integer
from sympy.matrices.dense import (eye, zeros)
i3 = Integer(3)
M = eye(100)
def timeit_Matrix__getitem_ii():
M[3, 3]
def timeit_Matrix__getitem_II():
M[i3, i3]
def timeit_Matrix__getslice():
M[:, :]
def timeit_Matrix_zeronm():
zeros(100, 100)
PK ]ZZZ��=� � & sympy/matrices/expressions/__init__.py""" A module which handles Matrix Expressions """
from .slice import MatrixSlice
from .blockmatrix import BlockMatrix, BlockDiagMatrix, block_collapse, blockcut
from .companion import CompanionMatrix
from .funcmatrix import FunctionMatrix
from .inverse import Inverse
from .matadd import MatAdd
from .matexpr import MatrixExpr, MatrixSymbol, matrix_symbols
from .matmul import MatMul
from .matpow import MatPow
from .trace import Trace, trace
from .determinant import Determinant, det, Permanent, per
from .transpose import Transpose
from .adjoint import Adjoint
from .hadamard import hadamard_product, HadamardProduct, hadamard_power, HadamardPower
from .diagonal import DiagonalMatrix, DiagonalOf, DiagMatrix, diagonalize_vector
from .dotproduct import DotProduct
from .kronecker import kronecker_product, KroneckerProduct, combine_kronecker
from .permutation import PermutationMatrix, MatrixPermute
from .sets import MatrixSet
from .special import ZeroMatrix, Identity, OneMatrix
__all__ = [
'MatrixSlice',
'BlockMatrix', 'BlockDiagMatrix', 'block_collapse', 'blockcut',
'FunctionMatrix',
'CompanionMatrix',
'Inverse',
'MatAdd',
'Identity', 'MatrixExpr', 'MatrixSymbol', 'ZeroMatrix', 'OneMatrix',
'matrix_symbols', 'MatrixSet',
'MatMul',
'MatPow',
'Trace', 'trace',
'Determinant', 'det',
'Transpose',
'Adjoint',
'hadamard_product', 'HadamardProduct', 'hadamard_power', 'HadamardPower',
'DiagonalMatrix', 'DiagonalOf', 'DiagMatrix', 'diagonalize_vector',
'DotProduct',
'kronecker_product', 'KroneckerProduct', 'combine_kronecker',
'PermutationMatrix', 'MatrixPermute',
'Permanent', 'per'
]
PK ]ZZZ���� � $ sympy/matrices/expressions/_shape.pyfrom sympy.core.relational import Eq
from sympy.core.expr import Expr
from sympy.core.numbers import Integer
from sympy.logic.boolalg import Boolean, And
from sympy.matrices.expressions.matexpr import MatrixExpr
from sympy.matrices.exceptions import ShapeError
from typing import Union
def is_matadd_valid(*args: MatrixExpr) -> Boolean:
"""Return the symbolic condition how ``MatAdd``, ``HadamardProduct``
makes sense.
Parameters
==========
args
The list of arguments of matrices to be tested for.
Examples
========
>>> from sympy import MatrixSymbol, symbols
>>> from sympy.matrices.expressions._shape import is_matadd_valid
>>> m, n, p, q = symbols('m n p q')
>>> A = MatrixSymbol('A', m, n)
>>> B = MatrixSymbol('B', p, q)
>>> is_matadd_valid(A, B)
Eq(m, p) & Eq(n, q)
"""
rows, cols = zip(*(arg.shape for arg in args))
return And(
*(Eq(i, j) for i, j in zip(rows[:-1], rows[1:])),
*(Eq(i, j) for i, j in zip(cols[:-1], cols[1:])),
)
def is_matmul_valid(*args: Union[MatrixExpr, Expr]) -> Boolean:
"""Return the symbolic condition how ``MatMul`` makes sense
Parameters
==========
args
The list of arguments of matrices and scalar expressions to be tested
for.
Examples
========
>>> from sympy import MatrixSymbol, symbols
>>> from sympy.matrices.expressions._shape import is_matmul_valid
>>> m, n, p, q = symbols('m n p q')
>>> A = MatrixSymbol('A', m, n)
>>> B = MatrixSymbol('B', p, q)
>>> is_matmul_valid(A, B)
Eq(n, p)
"""
rows, cols = zip(*(arg.shape for arg in args if isinstance(arg, MatrixExpr)))
return And(*(Eq(i, j) for i, j in zip(cols[:-1], rows[1:])))
def is_square(arg: MatrixExpr, /) -> Boolean:
"""Return the symbolic condition how the matrix is assumed to be square
Parameters
==========
arg
The matrix to be tested for.
Examples
========
>>> from sympy import MatrixSymbol, symbols
>>> from sympy.matrices.expressions._shape import is_square
>>> m, n = symbols('m n')
>>> A = MatrixSymbol('A', m, n)
>>> is_square(A)
Eq(m, n)
"""
return Eq(arg.rows, arg.cols)
def validate_matadd_integer(*args: MatrixExpr) -> None:
"""Validate matrix shape for addition only for integer values"""
rows, cols = zip(*(x.shape for x in args))
if len(set(filter(lambda x: isinstance(x, (int, Integer)), rows))) > 1:
raise ShapeError(f"Matrices have mismatching shape: {rows}")
if len(set(filter(lambda x: isinstance(x, (int, Integer)), cols))) > 1:
raise ShapeError(f"Matrices have mismatching shape: {cols}")
def validate_matmul_integer(*args: MatrixExpr) -> None:
"""Validate matrix shape for multiplication only for integer values"""
for A, B in zip(args[:-1], args[1:]):
i, j = A.cols, B.rows
if isinstance(i, (int, Integer)) and isinstance(j, (int, Integer)) and i != j:
raise ShapeError("Matrices are not aligned", i, j)
PK ]ZZZu�G�� � % sympy/matrices/expressions/adjoint.pyfrom sympy.core import Basic
from sympy.functions import adjoint, conjugate
from sympy.matrices.expressions.matexpr import MatrixExpr
class Adjoint(MatrixExpr):
"""
The Hermitian adjoint of a matrix expression.
This is a symbolic object that simply stores its argument without
evaluating it. To actually compute the adjoint, use the ``adjoint()``
function.
Examples
========
>>> from sympy import MatrixSymbol, Adjoint, adjoint
>>> A = MatrixSymbol('A', 3, 5)
>>> B = MatrixSymbol('B', 5, 3)
>>> Adjoint(A*B)
Adjoint(A*B)
>>> adjoint(A*B)
Adjoint(B)*Adjoint(A)
>>> adjoint(A*B) == Adjoint(A*B)
False
>>> adjoint(A*B) == Adjoint(A*B).doit()
True
"""
is_Adjoint = True
def doit(self, **hints):
arg = self.arg
if hints.get('deep', True) and isinstance(arg, Basic):
return adjoint(arg.doit(**hints))
else:
return adjoint(self.arg)
@property
def arg(self):
return self.args[0]
@property
def shape(self):
return self.arg.shape[::-1]
def _entry(self, i, j, **kwargs):
return conjugate(self.arg._entry(j, i, **kwargs))
def _eval_adjoint(self):
return self.arg
def _eval_transpose(self):
return self.arg.conjugate()
def _eval_conjugate(self):
return self.arg.transpose()
def _eval_trace(self):
from sympy.matrices.expressions.trace import Trace
return conjugate(Trace(self.arg))
PK ]ZZZfo�b_ _ ' sympy/matrices/expressions/applyfunc.pyfrom sympy.core.expr import ExprBuilder
from sympy.core.function import (Function, FunctionClass, Lambda)
from sympy.core.symbol import Dummy
from sympy.core.sympify import sympify, _sympify
from sympy.matrices.expressions import MatrixExpr
from sympy.matrices.matrixbase import MatrixBase
class ElementwiseApplyFunction(MatrixExpr):
r"""
Apply function to a matrix elementwise without evaluating.
Examples
========
It can be created by calling ``.applyfunc(<function>)`` on a matrix
expression:
>>> from sympy import MatrixSymbol
>>> from sympy.matrices.expressions.applyfunc import ElementwiseApplyFunction
>>> from sympy import exp
>>> X = MatrixSymbol("X", 3, 3)
>>> X.applyfunc(exp)
Lambda(_d, exp(_d)).(X)
Otherwise using the class constructor:
>>> from sympy import eye
>>> expr = ElementwiseApplyFunction(exp, eye(3))
>>> expr
Lambda(_d, exp(_d)).(Matrix([
[1, 0, 0],
[0, 1, 0],
[0, 0, 1]]))
>>> expr.doit()
Matrix([
[E, 1, 1],
[1, E, 1],
[1, 1, E]])
Notice the difference with the real mathematical functions:
>>> exp(eye(3))
Matrix([
[E, 0, 0],
[0, E, 0],
[0, 0, E]])
"""
def __new__(cls, function, expr):
expr = _sympify(expr)
if not expr.is_Matrix:
raise ValueError("{} must be a matrix instance.".format(expr))
if expr.shape == (1, 1):
# Check if the function returns a matrix, in that case, just apply
# the function instead of creating an ElementwiseApplyFunc object:
ret = function(expr)
if isinstance(ret, MatrixExpr):
return ret
if not isinstance(function, (FunctionClass, Lambda)):
d = Dummy('d')
function = Lambda(d, function(d))
function = sympify(function)
if not isinstance(function, (FunctionClass, Lambda)):
raise ValueError(
"{} should be compatible with SymPy function classes."
.format(function))
if 1 not in function.nargs:
raise ValueError(
'{} should be able to accept 1 arguments.'.format(function))
if not isinstance(function, Lambda):
d = Dummy('d')
function = Lambda(d, function(d))
obj = MatrixExpr.__new__(cls, function, expr)
return obj
@property
def function(self):
return self.args[0]
@property
def expr(self):
return self.args[1]
@property
def shape(self):
return self.expr.shape
def doit(self, **hints):
deep = hints.get("deep", True)
expr = self.expr
if deep:
expr = expr.doit(**hints)
function = self.function
if isinstance(function, Lambda) and function.is_identity:
# This is a Lambda containing the identity function.
return expr
if isinstance(expr, MatrixBase):
return expr.applyfunc(self.function)
elif isinstance(expr, ElementwiseApplyFunction):
return ElementwiseApplyFunction(
lambda x: self.function(expr.function(x)),
expr.expr
).doit(**hints)
else:
return self
def _entry(self, i, j, **kwargs):
return self.function(self.expr._entry(i, j, **kwargs))
def _get_function_fdiff(self):
d = Dummy("d")
function = self.function(d)
fdiff = function.diff(d)
if isinstance(fdiff, Function):
fdiff = type(fdiff)
else:
fdiff = Lambda(d, fdiff)
return fdiff
def _eval_derivative(self, x):
from sympy.matrices.expressions.hadamard import hadamard_product
dexpr = self.expr.diff(x)
fdiff = self._get_function_fdiff()
return hadamard_product(
dexpr,
ElementwiseApplyFunction(fdiff, self.expr)
)
def _eval_derivative_matrix_lines(self, x):
from sympy.matrices.expressions.special import Identity
from sympy.tensor.array.expressions.array_expressions import ArrayContraction
from sympy.tensor.array.expressions.array_expressions import ArrayDiagonal
from sympy.tensor.array.expressions.array_expressions import ArrayTensorProduct
fdiff = self._get_function_fdiff()
lr = self.expr._eval_derivative_matrix_lines(x)
ewdiff = ElementwiseApplyFunction(fdiff, self.expr)
if 1 in x.shape:
# Vector:
iscolumn = self.shape[1] == 1
for i in lr:
if iscolumn:
ptr1 = i.first_pointer
ptr2 = Identity(self.shape[1])
else:
ptr1 = Identity(self.shape[0])
ptr2 = i.second_pointer
subexpr = ExprBuilder(
ArrayDiagonal,
[
ExprBuilder(
ArrayTensorProduct,
[
ewdiff,
ptr1,
ptr2,
]
),
(0, 2) if iscolumn else (1, 4)
],
validator=ArrayDiagonal._validate
)
i._lines = [subexpr]
i._first_pointer_parent = subexpr.args[0].args
i._first_pointer_index = 1
i._second_pointer_parent = subexpr.args[0].args
i._second_pointer_index = 2
else:
# Matrix case:
for i in lr:
ptr1 = i.first_pointer
ptr2 = i.second_pointer
newptr1 = Identity(ptr1.shape[1])
newptr2 = Identity(ptr2.shape[1])
subexpr = ExprBuilder(
ArrayContraction,
[
ExprBuilder(
ArrayTensorProduct,
[ptr1, newptr1, ewdiff, ptr2, newptr2]
),
(1, 2, 4),
(5, 7, 8),
],
validator=ArrayContraction._validate
)
i._first_pointer_parent = subexpr.args[0].args
i._first_pointer_index = 1
i._second_pointer_parent = subexpr.args[0].args
i._second_pointer_index = 4
i._lines = [subexpr]
return lr
def _eval_transpose(self):
from sympy.matrices.expressions.transpose import Transpose
return self.func(self.function, Transpose(self.expr).doit())
PK ]ZZZ�
��o| o| ) sympy/matrices/expressions/blockmatrix.pyfrom sympy.assumptions.ask import (Q, ask)
from sympy.core import Basic, Add, Mul, S
from sympy.core.sympify import _sympify
from sympy.functions import adjoint
from sympy.functions.elementary.complexes import re, im
from sympy.strategies import typed, exhaust, condition, do_one, unpack
from sympy.strategies.traverse import bottom_up
from sympy.utilities.iterables import is_sequence, sift
from sympy.utilities.misc import filldedent
from sympy.matrices import Matrix, ShapeError
from sympy.matrices.exceptions import NonInvertibleMatrixError
from sympy.matrices.expressions.determinant import det, Determinant
from sympy.matrices.expressions.inverse import Inverse
from sympy.matrices.expressions.matadd import MatAdd
from sympy.matrices.expressions.matexpr import MatrixExpr, MatrixElement
from sympy.matrices.expressions.matmul import MatMul
from sympy.matrices.expressions.matpow import MatPow
from sympy.matrices.expressions.slice import MatrixSlice
from sympy.matrices.expressions.special import ZeroMatrix, Identity
from sympy.matrices.expressions.trace import trace
from sympy.matrices.expressions.transpose import Transpose, transpose
class BlockMatrix(MatrixExpr):
"""A BlockMatrix is a Matrix comprised of other matrices.
The submatrices are stored in a SymPy Matrix object but accessed as part of
a Matrix Expression
>>> from sympy import (MatrixSymbol, BlockMatrix, symbols,
... Identity, ZeroMatrix, block_collapse)
>>> n,m,l = symbols('n m l')
>>> X = MatrixSymbol('X', n, n)
>>> Y = MatrixSymbol('Y', m, m)
>>> Z = MatrixSymbol('Z', n, m)
>>> B = BlockMatrix([[X, Z], [ZeroMatrix(m,n), Y]])
>>> print(B)
Matrix([
[X, Z],
[0, Y]])
>>> C = BlockMatrix([[Identity(n), Z]])
>>> print(C)
Matrix([[I, Z]])
>>> print(block_collapse(C*B))
Matrix([[X, Z + Z*Y]])
Some matrices might be comprised of rows of blocks with
the matrices in each row having the same height and the
rows all having the same total number of columns but
not having the same number of columns for each matrix
in each row. In this case, the matrix is not a block
matrix and should be instantiated by Matrix.
>>> from sympy import ones, Matrix
>>> dat = [
... [ones(3,2), ones(3,3)*2],
... [ones(2,3)*3, ones(2,2)*4]]
...
>>> BlockMatrix(dat)
Traceback (most recent call last):
...
ValueError:
Although this matrix is comprised of blocks, the blocks do not fill
the matrix in a size-symmetric fashion. To create a full matrix from
these arguments, pass them directly to Matrix.
>>> Matrix(dat)
Matrix([
[1, 1, 2, 2, 2],
[1, 1, 2, 2, 2],
[1, 1, 2, 2, 2],
[3, 3, 3, 4, 4],
[3, 3, 3, 4, 4]])
See Also
========
sympy.matrices.matrixbase.MatrixBase.irregular
"""
def __new__(cls, *args, **kwargs):
from sympy.matrices.immutable import ImmutableDenseMatrix
isMat = lambda i: getattr(i, 'is_Matrix', False)
if len(args) != 1 or \
not is_sequence(args[0]) or \
len({isMat(r) for r in args[0]}) != 1:
raise ValueError(filldedent('''
expecting a sequence of 1 or more rows
containing Matrices.'''))
rows = args[0] if args else []
if not isMat(rows):
if rows and isMat(rows[0]):
rows = [rows] # rows is not list of lists or []
# regularity check
# same number of matrices in each row
blocky = ok = len({len(r) for r in rows}) == 1
if ok:
# same number of rows for each matrix in a row
for r in rows:
ok = len({i.rows for i in r}) == 1
if not ok:
break
blocky = ok
if ok:
# same number of cols for each matrix in each col
for c in range(len(rows[0])):
ok = len({rows[i][c].cols
for i in range(len(rows))}) == 1
if not ok:
break
if not ok:
# same total cols in each row
ok = len({
sum(i.cols for i in r) for r in rows}) == 1
if blocky and ok:
raise ValueError(filldedent('''
Although this matrix is comprised of blocks,
the blocks do not fill the matrix in a
size-symmetric fashion. To create a full matrix
from these arguments, pass them directly to
Matrix.'''))
raise ValueError(filldedent('''
When there are not the same number of rows in each
row's matrices or there are not the same number of
total columns in each row, the matrix is not a
block matrix. If this matrix is known to consist of
blocks fully filling a 2-D space then see
Matrix.irregular.'''))
mat = ImmutableDenseMatrix(rows, evaluate=False)
obj = Basic.__new__(cls, mat)
return obj
@property
def shape(self):
numrows = numcols = 0
M = self.blocks
for i in range(M.shape[0]):
numrows += M[i, 0].shape[0]
for i in range(M.shape[1]):
numcols += M[0, i].shape[1]
return (numrows, numcols)
@property
def blockshape(self):
return self.blocks.shape
@property
def blocks(self):
return self.args[0]
@property
def rowblocksizes(self):
return [self.blocks[i, 0].rows for i in range(self.blockshape[0])]
@property
def colblocksizes(self):
return [self.blocks[0, i].cols for i in range(self.blockshape[1])]
def structurally_equal(self, other):
return (isinstance(other, BlockMatrix)
and self.shape == other.shape
and self.blockshape == other.blockshape
and self.rowblocksizes == other.rowblocksizes
and self.colblocksizes == other.colblocksizes)
def _blockmul(self, other):
if (isinstance(other, BlockMatrix) and
self.colblocksizes == other.rowblocksizes):
return BlockMatrix(self.blocks*other.blocks)
return self * other
def _blockadd(self, other):
if (isinstance(other, BlockMatrix)
and self.structurally_equal(other)):
return BlockMatrix(self.blocks + other.blocks)
return self + other
def _eval_transpose(self):
# Flip all the individual matrices
matrices = [transpose(matrix) for matrix in self.blocks]
# Make a copy
M = Matrix(self.blockshape[0], self.blockshape[1], matrices)
# Transpose the block structure
M = M.transpose()
return BlockMatrix(M)
def _eval_adjoint(self):
# Adjoint all the individual matrices
matrices = [adjoint(matrix) for matrix in self.blocks]
# Make a copy
M = Matrix(self.blockshape[0], self.blockshape[1], matrices)
# Transpose the block structure
M = M.transpose()
return BlockMatrix(M)
def _eval_trace(self):
if self.rowblocksizes == self.colblocksizes:
blocks = [self.blocks[i, i] for i in range(self.blockshape[0])]
return Add(*[trace(block) for block in blocks])
def _eval_determinant(self):
if self.blockshape == (1, 1):
return det(self.blocks[0, 0])
if self.blockshape == (2, 2):
[[A, B],
[C, D]] = self.blocks.tolist()
if ask(Q.invertible(A)):
return det(A)*det(D - C*A.I*B)
elif ask(Q.invertible(D)):
return det(D)*det(A - B*D.I*C)
return Determinant(self)
def _eval_as_real_imag(self):
real_matrices = [re(matrix) for matrix in self.blocks]
real_matrices = Matrix(self.blockshape[0], self.blockshape[1], real_matrices)
im_matrices = [im(matrix) for matrix in self.blocks]
im_matrices = Matrix(self.blockshape[0], self.blockshape[1], im_matrices)
return (BlockMatrix(real_matrices), BlockMatrix(im_matrices))
def _eval_derivative(self, x):
return BlockMatrix(self.blocks.diff(x))
def transpose(self):
"""Return transpose of matrix.
Examples
========
>>> from sympy import MatrixSymbol, BlockMatrix, ZeroMatrix
>>> from sympy.abc import m, n
>>> X = MatrixSymbol('X', n, n)
>>> Y = MatrixSymbol('Y', m, m)
>>> Z = MatrixSymbol('Z', n, m)
>>> B = BlockMatrix([[X, Z], [ZeroMatrix(m,n), Y]])
>>> B.transpose()
Matrix([
[X.T, 0],
[Z.T, Y.T]])
>>> _.transpose()
Matrix([
[X, Z],
[0, Y]])
"""
return self._eval_transpose()
def schur(self, mat = 'A', generalized = False):
"""Return the Schur Complement of the 2x2 BlockMatrix
Parameters
==========
mat : String, optional
The matrix with respect to which the
Schur Complement is calculated. 'A' is
used by default
generalized : bool, optional
If True, returns the generalized Schur
Component which uses Moore-Penrose Inverse
Examples
========
>>> from sympy import symbols, MatrixSymbol, BlockMatrix
>>> m, n = symbols('m n')
>>> A = MatrixSymbol('A', n, n)
>>> B = MatrixSymbol('B', n, m)
>>> C = MatrixSymbol('C', m, n)
>>> D = MatrixSymbol('D', m, m)
>>> X = BlockMatrix([[A, B], [C, D]])
The default Schur Complement is evaluated with "A"
>>> X.schur()
-C*A**(-1)*B + D
>>> X.schur('D')
A - B*D**(-1)*C
Schur complement with non-invertible matrices is not
defined. Instead, the generalized Schur complement can
be calculated which uses the Moore-Penrose Inverse. To
achieve this, `generalized` must be set to `True`
>>> X.schur('B', generalized=True)
C - D*(B.T*B)**(-1)*B.T*A
>>> X.schur('C', generalized=True)
-A*(C.T*C)**(-1)*C.T*D + B
Returns
=======
M : Matrix
The Schur Complement Matrix
Raises
======
ShapeError
If the block matrix is not a 2x2 matrix
NonInvertibleMatrixError
If given matrix is non-invertible
References
==========
.. [1] Wikipedia Article on Schur Component : https://en.wikipedia.org/wiki/Schur_complement
See Also
========
sympy.matrices.matrixbase.MatrixBase.pinv
"""
if self.blockshape == (2, 2):
[[A, B],
[C, D]] = self.blocks.tolist()
d={'A' : A, 'B' : B, 'C' : C, 'D' : D}
try:
inv = (d[mat].T*d[mat]).inv()*d[mat].T if generalized else d[mat].inv()
if mat == 'A':
return D - C * inv * B
elif mat == 'B':
return C - D * inv * A
elif mat == 'C':
return B - A * inv * D
elif mat == 'D':
return A - B * inv * C
#For matrices where no sub-matrix is square
return self
except NonInvertibleMatrixError:
raise NonInvertibleMatrixError('The given matrix is not invertible. Please set generalized=True \
to compute the generalized Schur Complement which uses Moore-Penrose Inverse')
else:
raise ShapeError('Schur Complement can only be calculated for 2x2 block matrices')
def LDUdecomposition(self):
"""Returns the Block LDU decomposition of
a 2x2 Block Matrix
Returns
=======
(L, D, U) : Matrices
L : Lower Diagonal Matrix
D : Diagonal Matrix
U : Upper Diagonal Matrix
Examples
========
>>> from sympy import symbols, MatrixSymbol, BlockMatrix, block_collapse
>>> m, n = symbols('m n')
>>> A = MatrixSymbol('A', n, n)
>>> B = MatrixSymbol('B', n, m)
>>> C = MatrixSymbol('C', m, n)
>>> D = MatrixSymbol('D', m, m)
>>> X = BlockMatrix([[A, B], [C, D]])
>>> L, D, U = X.LDUdecomposition()
>>> block_collapse(L*D*U)
Matrix([
[A, B],
[C, D]])
Raises
======
ShapeError
If the block matrix is not a 2x2 matrix
NonInvertibleMatrixError
If the matrix "A" is non-invertible
See Also
========
sympy.matrices.expressions.blockmatrix.BlockMatrix.UDLdecomposition
sympy.matrices.expressions.blockmatrix.BlockMatrix.LUdecomposition
"""
if self.blockshape == (2,2):
[[A, B],
[C, D]] = self.blocks.tolist()
try:
AI = A.I
except NonInvertibleMatrixError:
raise NonInvertibleMatrixError('Block LDU decomposition cannot be calculated when\
"A" is singular')
Ip = Identity(B.shape[0])
Iq = Identity(B.shape[1])
Z = ZeroMatrix(*B.shape)
L = BlockMatrix([[Ip, Z], [C*AI, Iq]])
D = BlockDiagMatrix(A, self.schur())
U = BlockMatrix([[Ip, AI*B],[Z.T, Iq]])
return L, D, U
else:
raise ShapeError("Block LDU decomposition is supported only for 2x2 block matrices")
def UDLdecomposition(self):
"""Returns the Block UDL decomposition of
a 2x2 Block Matrix
Returns
=======
(U, D, L) : Matrices
U : Upper Diagonal Matrix
D : Diagonal Matrix
L : Lower Diagonal Matrix
Examples
========
>>> from sympy import symbols, MatrixSymbol, BlockMatrix, block_collapse
>>> m, n = symbols('m n')
>>> A = MatrixSymbol('A', n, n)
>>> B = MatrixSymbol('B', n, m)
>>> C = MatrixSymbol('C', m, n)
>>> D = MatrixSymbol('D', m, m)
>>> X = BlockMatrix([[A, B], [C, D]])
>>> U, D, L = X.UDLdecomposition()
>>> block_collapse(U*D*L)
Matrix([
[A, B],
[C, D]])
Raises
======
ShapeError
If the block matrix is not a 2x2 matrix
NonInvertibleMatrixError
If the matrix "D" is non-invertible
See Also
========
sympy.matrices.expressions.blockmatrix.BlockMatrix.LDUdecomposition
sympy.matrices.expressions.blockmatrix.BlockMatrix.LUdecomposition
"""
if self.blockshape == (2,2):
[[A, B],
[C, D]] = self.blocks.tolist()
try:
DI = D.I
except NonInvertibleMatrixError:
raise NonInvertibleMatrixError('Block UDL decomposition cannot be calculated when\
"D" is singular')
Ip = Identity(A.shape[0])
Iq = Identity(B.shape[1])
Z = ZeroMatrix(*B.shape)
U = BlockMatrix([[Ip, B*DI], [Z.T, Iq]])
D = BlockDiagMatrix(self.schur('D'), D)
L = BlockMatrix([[Ip, Z],[DI*C, Iq]])
return U, D, L
else:
raise ShapeError("Block UDL decomposition is supported only for 2x2 block matrices")
def LUdecomposition(self):
"""Returns the Block LU decomposition of
a 2x2 Block Matrix
Returns
=======
(L, U) : Matrices
L : Lower Diagonal Matrix
U : Upper Diagonal Matrix
Examples
========
>>> from sympy import symbols, MatrixSymbol, BlockMatrix, block_collapse
>>> m, n = symbols('m n')
>>> A = MatrixSymbol('A', n, n)
>>> B = MatrixSymbol('B', n, m)
>>> C = MatrixSymbol('C', m, n)
>>> D = MatrixSymbol('D', m, m)
>>> X = BlockMatrix([[A, B], [C, D]])
>>> L, U = X.LUdecomposition()
>>> block_collapse(L*U)
Matrix([
[A, B],
[C, D]])
Raises
======
ShapeError
If the block matrix is not a 2x2 matrix
NonInvertibleMatrixError
If the matrix "A" is non-invertible
See Also
========
sympy.matrices.expressions.blockmatrix.BlockMatrix.UDLdecomposition
sympy.matrices.expressions.blockmatrix.BlockMatrix.LDUdecomposition
"""
if self.blockshape == (2,2):
[[A, B],
[C, D]] = self.blocks.tolist()
try:
A = A**S.Half
AI = A.I
except NonInvertibleMatrixError:
raise NonInvertibleMatrixError('Block LU decomposition cannot be calculated when\
"A" is singular')
Z = ZeroMatrix(*B.shape)
Q = self.schur()**S.Half
L = BlockMatrix([[A, Z], [C*AI, Q]])
U = BlockMatrix([[A, AI*B],[Z.T, Q]])
return L, U
else:
raise ShapeError("Block LU decomposition is supported only for 2x2 block matrices")
def _entry(self, i, j, **kwargs):
# Find row entry
orig_i, orig_j = i, j
for row_block, numrows in enumerate(self.rowblocksizes):
cmp = i < numrows
if cmp == True:
break
elif cmp == False:
i -= numrows
elif row_block < self.blockshape[0] - 1:
# Can't tell which block and it's not the last one, return unevaluated
return MatrixElement(self, orig_i, orig_j)
for col_block, numcols in enumerate(self.colblocksizes):
cmp = j < numcols
if cmp == True:
break
elif cmp == False:
j -= numcols
elif col_block < self.blockshape[1] - 1:
return MatrixElement(self, orig_i, orig_j)
return self.blocks[row_block, col_block][i, j]
@property
def is_Identity(self):
if self.blockshape[0] != self.blockshape[1]:
return False
for i in range(self.blockshape[0]):
for j in range(self.blockshape[1]):
if i==j and not self.blocks[i, j].is_Identity:
return False
if i!=j and not self.blocks[i, j].is_ZeroMatrix:
return False
return True
@property
def is_structurally_symmetric(self):
return self.rowblocksizes == self.colblocksizes
def equals(self, other):
if self == other:
return True
if (isinstance(other, BlockMatrix) and self.blocks == other.blocks):
return True
return super().equals(other)
class BlockDiagMatrix(BlockMatrix):
"""A sparse matrix with block matrices along its diagonals
Examples
========
>>> from sympy import MatrixSymbol, BlockDiagMatrix, symbols
>>> n, m, l = symbols('n m l')
>>> X = MatrixSymbol('X', n, n)
>>> Y = MatrixSymbol('Y', m, m)
>>> BlockDiagMatrix(X, Y)
Matrix([
[X, 0],
[0, Y]])
Notes
=====
If you want to get the individual diagonal blocks, use
:meth:`get_diag_blocks`.
See Also
========
sympy.matrices.dense.diag
"""
def __new__(cls, *mats):
return Basic.__new__(BlockDiagMatrix, *[_sympify(m) for m in mats])
@property
def diag(self):
return self.args
@property
def blocks(self):
from sympy.matrices.immutable import ImmutableDenseMatrix
mats = self.args
data = [[mats[i] if i == j else ZeroMatrix(mats[i].rows, mats[j].cols)
for j in range(len(mats))]
for i in range(len(mats))]
return ImmutableDenseMatrix(data, evaluate=False)
@property
def shape(self):
return (sum(block.rows for block in self.args),
sum(block.cols for block in self.args))
@property
def blockshape(self):
n = len(self.args)
return (n, n)
@property
def rowblocksizes(self):
return [block.rows for block in self.args]
@property
def colblocksizes(self):
return [block.cols for block in self.args]
def _all_square_blocks(self):
"""Returns true if all blocks are square"""
return all(mat.is_square for mat in self.args)
def _eval_determinant(self):
if self._all_square_blocks():
return Mul(*[det(mat) for mat in self.args])
# At least one block is non-square. Since the entire matrix must be square we know there must
# be at least two blocks in this matrix, in which case the entire matrix is necessarily rank-deficient
return S.Zero
def _eval_inverse(self, expand='ignored'):
if self._all_square_blocks():
return BlockDiagMatrix(*[mat.inverse() for mat in self.args])
# See comment in _eval_determinant()
raise NonInvertibleMatrixError('Matrix det == 0; not invertible.')
def _eval_transpose(self):
return BlockDiagMatrix(*[mat.transpose() for mat in self.args])
def _blockmul(self, other):
if (isinstance(other, BlockDiagMatrix) and
self.colblocksizes == other.rowblocksizes):
return BlockDiagMatrix(*[a*b for a, b in zip(self.args, other.args)])
else:
return BlockMatrix._blockmul(self, other)
def _blockadd(self, other):
if (isinstance(other, BlockDiagMatrix) and
self.blockshape == other.blockshape and
self.rowblocksizes == other.rowblocksizes and
self.colblocksizes == other.colblocksizes):
return BlockDiagMatrix(*[a + b for a, b in zip(self.args, other.args)])
else:
return BlockMatrix._blockadd(self, other)
def get_diag_blocks(self):
"""Return the list of diagonal blocks of the matrix.
Examples
========
>>> from sympy import BlockDiagMatrix, Matrix
>>> A = Matrix([[1, 2], [3, 4]])
>>> B = Matrix([[5, 6], [7, 8]])
>>> M = BlockDiagMatrix(A, B)
How to get diagonal blocks from the block diagonal matrix:
>>> diag_blocks = M.get_diag_blocks()
>>> diag_blocks[0]
Matrix([
[1, 2],
[3, 4]])
>>> diag_blocks[1]
Matrix([
[5, 6],
[7, 8]])
"""
return self.args
def block_collapse(expr):
"""Evaluates a block matrix expression
>>> from sympy import MatrixSymbol, BlockMatrix, symbols, Identity, ZeroMatrix, block_collapse
>>> n,m,l = symbols('n m l')
>>> X = MatrixSymbol('X', n, n)
>>> Y = MatrixSymbol('Y', m, m)
>>> Z = MatrixSymbol('Z', n, m)
>>> B = BlockMatrix([[X, Z], [ZeroMatrix(m, n), Y]])
>>> print(B)
Matrix([
[X, Z],
[0, Y]])
>>> C = BlockMatrix([[Identity(n), Z]])
>>> print(C)
Matrix([[I, Z]])
>>> print(block_collapse(C*B))
Matrix([[X, Z + Z*Y]])
"""
from sympy.strategies.util import expr_fns
hasbm = lambda expr: isinstance(expr, MatrixExpr) and expr.has(BlockMatrix)
conditioned_rl = condition(
hasbm,
typed(
{MatAdd: do_one(bc_matadd, bc_block_plus_ident),
MatMul: do_one(bc_matmul, bc_dist),
MatPow: bc_matmul,
Transpose: bc_transpose,
Inverse: bc_inverse,
BlockMatrix: do_one(bc_unpack, deblock)}
)
)
rule = exhaust(
bottom_up(
exhaust(conditioned_rl),
fns=expr_fns
)
)
result = rule(expr)
doit = getattr(result, 'doit', None)
if doit is not None:
return doit()
else:
return result
def bc_unpack(expr):
if expr.blockshape == (1, 1):
return expr.blocks[0, 0]
return expr
def bc_matadd(expr):
args = sift(expr.args, lambda M: isinstance(M, BlockMatrix))
blocks = args[True]
if not blocks:
return expr
nonblocks = args[False]
block = blocks[0]
for b in blocks[1:]:
block = block._blockadd(b)
if nonblocks:
return MatAdd(*nonblocks) + block
else:
return block
def bc_block_plus_ident(expr):
idents = [arg for arg in expr.args if arg.is_Identity]
if not idents:
return expr
blocks = [arg for arg in expr.args if isinstance(arg, BlockMatrix)]
if (blocks and all(b.structurally_equal(blocks[0]) for b in blocks)
and blocks[0].is_structurally_symmetric):
block_id = BlockDiagMatrix(*[Identity(k)
for k in blocks[0].rowblocksizes])
rest = [arg for arg in expr.args if not arg.is_Identity and not isinstance(arg, BlockMatrix)]
return MatAdd(block_id * len(idents), *blocks, *rest).doit()
return expr
def bc_dist(expr):
""" Turn a*[X, Y] into [a*X, a*Y] """
factor, mat = expr.as_coeff_mmul()
if factor == 1:
return expr
unpacked = unpack(mat)
if isinstance(unpacked, BlockDiagMatrix):
B = unpacked.diag
new_B = [factor * mat for mat in B]
return BlockDiagMatrix(*new_B)
elif isinstance(unpacked, BlockMatrix):
B = unpacked.blocks
new_B = [
[factor * B[i, j] for j in range(B.cols)] for i in range(B.rows)]
return BlockMatrix(new_B)
return expr
def bc_matmul(expr):
if isinstance(expr, MatPow):
if expr.args[1].is_Integer and expr.args[1] > 0:
factor, matrices = 1, [expr.args[0]]*expr.args[1]
else:
return expr
else:
factor, matrices = expr.as_coeff_matrices()
i = 0
while (i+1 < len(matrices)):
A, B = matrices[i:i+2]
if isinstance(A, BlockMatrix) and isinstance(B, BlockMatrix):
matrices[i] = A._blockmul(B)
matrices.pop(i+1)
elif isinstance(A, BlockMatrix):
matrices[i] = A._blockmul(BlockMatrix([[B]]))
matrices.pop(i+1)
elif isinstance(B, BlockMatrix):
matrices[i] = BlockMatrix([[A]])._blockmul(B)
matrices.pop(i+1)
else:
i+=1
return MatMul(factor, *matrices).doit()
def bc_transpose(expr):
collapse = block_collapse(expr.arg)
return collapse._eval_transpose()
def bc_inverse(expr):
if isinstance(expr.arg, BlockDiagMatrix):
return expr.inverse()
expr2 = blockinverse_1x1(expr)
if expr != expr2:
return expr2
return blockinverse_2x2(Inverse(reblock_2x2(expr.arg)))
def blockinverse_1x1(expr):
if isinstance(expr.arg, BlockMatrix) and expr.arg.blockshape == (1, 1):
mat = Matrix([[expr.arg.blocks[0].inverse()]])
return BlockMatrix(mat)
return expr
def blockinverse_2x2(expr):
if isinstance(expr.arg, BlockMatrix) and expr.arg.blockshape == (2, 2):
# See: Inverses of 2x2 Block Matrices, Tzon-Tzer Lu and Sheng-Hua Shiou
[[A, B],
[C, D]] = expr.arg.blocks.tolist()
formula = _choose_2x2_inversion_formula(A, B, C, D)
if formula != None:
MI = expr.arg.schur(formula).I
if formula == 'A':
AI = A.I
return BlockMatrix([[AI + AI * B * MI * C * AI, -AI * B * MI], [-MI * C * AI, MI]])
if formula == 'B':
BI = B.I
return BlockMatrix([[-MI * D * BI, MI], [BI + BI * A * MI * D * BI, -BI * A * MI]])
if formula == 'C':
CI = C.I
return BlockMatrix([[-CI * D * MI, CI + CI * D * MI * A * CI], [MI, -MI * A * CI]])
if formula == 'D':
DI = D.I
return BlockMatrix([[MI, -MI * B * DI], [-DI * C * MI, DI + DI * C * MI * B * DI]])
return expr
def _choose_2x2_inversion_formula(A, B, C, D):
"""
Assuming [[A, B], [C, D]] would form a valid square block matrix, find
which of the classical 2x2 block matrix inversion formulas would be
best suited.
Returns 'A', 'B', 'C', 'D' to represent the algorithm involving inversion
of the given argument or None if the matrix cannot be inverted using
any of those formulas.
"""
# Try to find a known invertible matrix. Note that the Schur complement
# is currently not being considered for this
A_inv = ask(Q.invertible(A))
if A_inv == True:
return 'A'
B_inv = ask(Q.invertible(B))
if B_inv == True:
return 'B'
C_inv = ask(Q.invertible(C))
if C_inv == True:
return 'C'
D_inv = ask(Q.invertible(D))
if D_inv == True:
return 'D'
# Otherwise try to find a matrix that isn't known to be non-invertible
if A_inv != False:
return 'A'
if B_inv != False:
return 'B'
if C_inv != False:
return 'C'
if D_inv != False:
return 'D'
return None
def deblock(B):
""" Flatten a BlockMatrix of BlockMatrices """
if not isinstance(B, BlockMatrix) or not B.blocks.has(BlockMatrix):
return B
wrap = lambda x: x if isinstance(x, BlockMatrix) else BlockMatrix([[x]])
bb = B.blocks.applyfunc(wrap) # everything is a block
try:
MM = Matrix(0, sum(bb[0, i].blocks.shape[1] for i in range(bb.shape[1])), [])
for row in range(0, bb.shape[0]):
M = Matrix(bb[row, 0].blocks)
for col in range(1, bb.shape[1]):
M = M.row_join(bb[row, col].blocks)
MM = MM.col_join(M)
return BlockMatrix(MM)
except ShapeError:
return B
def reblock_2x2(expr):
"""
Reblock a BlockMatrix so that it has 2x2 blocks of block matrices. If
possible in such a way that the matrix continues to be invertible using the
classical 2x2 block inversion formulas.
"""
if not isinstance(expr, BlockMatrix) or not all(d > 2 for d in expr.blockshape):
return expr
BM = BlockMatrix # for brevity's sake
rowblocks, colblocks = expr.blockshape
blocks = expr.blocks
for i in range(1, rowblocks):
for j in range(1, colblocks):
# try to split rows at i and cols at j
A = bc_unpack(BM(blocks[:i, :j]))
B = bc_unpack(BM(blocks[:i, j:]))
C = bc_unpack(BM(blocks[i:, :j]))
D = bc_unpack(BM(blocks[i:, j:]))
formula = _choose_2x2_inversion_formula(A, B, C, D)
if formula is not None:
return BlockMatrix([[A, B], [C, D]])
# else: nothing worked, just split upper left corner
return BM([[blocks[0, 0], BM(blocks[0, 1:])],
[BM(blocks[1:, 0]), BM(blocks[1:, 1:])]])
def bounds(sizes):
""" Convert sequence of numbers into pairs of low-high pairs
>>> from sympy.matrices.expressions.blockmatrix import bounds
>>> bounds((1, 10, 50))
[(0, 1), (1, 11), (11, 61)]
"""
low = 0
rv = []
for size in sizes:
rv.append((low, low + size))
low += size
return rv
def blockcut(expr, rowsizes, colsizes):
""" Cut a matrix expression into Blocks
>>> from sympy import ImmutableMatrix, blockcut
>>> M = ImmutableMatrix(4, 4, range(16))
>>> B = blockcut(M, (1, 3), (1, 3))
>>> type(B).__name__
'BlockMatrix'
>>> ImmutableMatrix(B.blocks[0, 1])
Matrix([[1, 2, 3]])
"""
rowbounds = bounds(rowsizes)
colbounds = bounds(colsizes)
return BlockMatrix([[MatrixSlice(expr, rowbound, colbound)
for colbound in colbounds]
for rowbound in rowbounds])
PK ]ZZZ(6sA� � ' sympy/matrices/expressions/companion.pyfrom sympy.core.singleton import S
from sympy.core.sympify import _sympify
from sympy.polys.polytools import Poly
from .matexpr import MatrixExpr
class CompanionMatrix(MatrixExpr):
"""A symbolic companion matrix of a polynomial.
Examples
========
>>> from sympy import Poly, Symbol, symbols
>>> from sympy.matrices.expressions import CompanionMatrix
>>> x = Symbol('x')
>>> c0, c1, c2, c3, c4 = symbols('c0:5')
>>> p = Poly(c0 + c1*x + c2*x**2 + c3*x**3 + c4*x**4 + x**5, x)
>>> CompanionMatrix(p)
CompanionMatrix(Poly(x**5 + c4*x**4 + c3*x**3 + c2*x**2 + c1*x + c0,
x, domain='ZZ[c0,c1,c2,c3,c4]'))
"""
def __new__(cls, poly):
poly = _sympify(poly)
if not isinstance(poly, Poly):
raise ValueError("{} must be a Poly instance.".format(poly))
if not poly.is_monic:
raise ValueError("{} must be a monic polynomial.".format(poly))
if not poly.is_univariate:
raise ValueError(
"{} must be a univariate polynomial.".format(poly))
if not poly.degree() >= 1:
raise ValueError(
"{} must have degree not less than 1.".format(poly))
return super().__new__(cls, poly)
@property
def shape(self):
poly = self.args[0]
size = poly.degree()
return size, size
def _entry(self, i, j):
if j == self.cols - 1:
return -self.args[0].all_coeffs()[-1 - i]
elif i == j + 1:
return S.One
return S.Zero
def as_explicit(self):
from sympy.matrices.immutable import ImmutableDenseMatrix
return ImmutableDenseMatrix.companion(self.args[0])
PK ]ZZZx �� � ) sympy/matrices/expressions/determinant.pyfrom sympy.core.basic import Basic
from sympy.core.expr import Expr
from sympy.core.singleton import S
from sympy.core.sympify import sympify
from sympy.matrices.exceptions import NonSquareMatrixError
from sympy.matrices.matrixbase import MatrixBase
class Determinant(Expr):
"""Matrix Determinant
Represents the determinant of a matrix expression.
Examples
========
>>> from sympy import MatrixSymbol, Determinant, eye
>>> A = MatrixSymbol('A', 3, 3)
>>> Determinant(A)
Determinant(A)
>>> Determinant(eye(3)).doit()
1
"""
is_commutative = True
def __new__(cls, mat):
mat = sympify(mat)
if not mat.is_Matrix:
raise TypeError("Input to Determinant, %s, not a matrix" % str(mat))
if mat.is_square is False:
raise NonSquareMatrixError("Det of a non-square matrix")
return Basic.__new__(cls, mat)
@property
def arg(self):
return self.args[0]
@property
def kind(self):
return self.arg.kind.element_kind
def doit(self, **hints):
arg = self.arg
if hints.get('deep', True):
arg = arg.doit(**hints)
result = arg._eval_determinant()
if result is not None:
return result
return self
def det(matexpr):
""" Matrix Determinant
Examples
========
>>> from sympy import MatrixSymbol, det, eye
>>> A = MatrixSymbol('A', 3, 3)
>>> det(A)
Determinant(A)
>>> det(eye(3))
1
"""
return Determinant(matexpr).doit()
class Permanent(Expr):
"""Matrix Permanent
Represents the permanent of a matrix expression.
Examples
========
>>> from sympy import MatrixSymbol, Permanent, ones
>>> A = MatrixSymbol('A', 3, 3)
>>> Permanent(A)
Permanent(A)
>>> Permanent(ones(3, 3)).doit()
6
"""
def __new__(cls, mat):
mat = sympify(mat)
if not mat.is_Matrix:
raise TypeError("Input to Permanent, %s, not a matrix" % str(mat))
return Basic.__new__(cls, mat)
@property
def arg(self):
return self.args[0]
def doit(self, expand=False, **hints):
if isinstance(self.arg, MatrixBase):
return self.arg.per()
else:
return self
def per(matexpr):
""" Matrix Permanent
Examples
========
>>> from sympy import MatrixSymbol, Matrix, per, ones
>>> A = MatrixSymbol('A', 3, 3)
>>> per(A)
Permanent(A)
>>> per(ones(5, 5))
120
>>> M = Matrix([1, 2, 5])
>>> per(M)
8
"""
return Permanent(matexpr).doit()
from sympy.assumptions.ask import ask, Q
from sympy.assumptions.refine import handlers_dict
def refine_Determinant(expr, assumptions):
"""
>>> from sympy import MatrixSymbol, Q, assuming, refine, det
>>> X = MatrixSymbol('X', 2, 2)
>>> det(X)
Determinant(X)
>>> with assuming(Q.orthogonal(X)):
... print(refine(det(X)))
1
"""
if ask(Q.orthogonal(expr.arg), assumptions):
return S.One
elif ask(Q.singular(expr.arg), assumptions):
return S.Zero
elif ask(Q.unit_triangular(expr.arg), assumptions):
return S.One
return expr
handlers_dict['Determinant'] = refine_Determinant
PK ]ZZZ9�u� � & sympy/matrices/expressions/diagonal.pyfrom sympy.core.sympify import _sympify
from sympy.matrices.expressions import MatrixExpr
from sympy.core import S, Eq, Ge
from sympy.core.mul import Mul
from sympy.functions.special.tensor_functions import KroneckerDelta
class DiagonalMatrix(MatrixExpr):
"""DiagonalMatrix(M) will create a matrix expression that
behaves as though all off-diagonal elements,
`M[i, j]` where `i != j`, are zero.
Examples
========
>>> from sympy import MatrixSymbol, DiagonalMatrix, Symbol
>>> n = Symbol('n', integer=True)
>>> m = Symbol('m', integer=True)
>>> D = DiagonalMatrix(MatrixSymbol('x', 2, 3))
>>> D[1, 2]
0
>>> D[1, 1]
x[1, 1]
The length of the diagonal -- the lesser of the two dimensions of `M` --
is accessed through the `diagonal_length` property:
>>> D.diagonal_length
2
>>> DiagonalMatrix(MatrixSymbol('x', n + 1, n)).diagonal_length
n
When one of the dimensions is symbolic the other will be treated as
though it is smaller:
>>> tall = DiagonalMatrix(MatrixSymbol('x', n, 3))
>>> tall.diagonal_length
3
>>> tall[10, 1]
0
When the size of the diagonal is not known, a value of None will
be returned:
>>> DiagonalMatrix(MatrixSymbol('x', n, m)).diagonal_length is None
True
"""
arg = property(lambda self: self.args[0])
shape = property(lambda self: self.arg.shape) # type:ignore
@property
def diagonal_length(self):
r, c = self.shape
if r.is_Integer and c.is_Integer:
m = min(r, c)
elif r.is_Integer and not c.is_Integer:
m = r
elif c.is_Integer and not r.is_Integer:
m = c
elif r == c:
m = r
else:
try:
m = min(r, c)
except TypeError:
m = None
return m
def _entry(self, i, j, **kwargs):
if self.diagonal_length is not None:
if Ge(i, self.diagonal_length) is S.true:
return S.Zero
elif Ge(j, self.diagonal_length) is S.true:
return S.Zero
eq = Eq(i, j)
if eq is S.true:
return self.arg[i, i]
elif eq is S.false:
return S.Zero
return self.arg[i, j]*KroneckerDelta(i, j)
class DiagonalOf(MatrixExpr):
"""DiagonalOf(M) will create a matrix expression that
is equivalent to the diagonal of `M`, represented as
a single column matrix.
Examples
========
>>> from sympy import MatrixSymbol, DiagonalOf, Symbol
>>> n = Symbol('n', integer=True)
>>> m = Symbol('m', integer=True)
>>> x = MatrixSymbol('x', 2, 3)
>>> diag = DiagonalOf(x)
>>> diag.shape
(2, 1)
The diagonal can be addressed like a matrix or vector and will
return the corresponding element of the original matrix:
>>> diag[1, 0] == diag[1] == x[1, 1]
True
The length of the diagonal -- the lesser of the two dimensions of `M` --
is accessed through the `diagonal_length` property:
>>> diag.diagonal_length
2
>>> DiagonalOf(MatrixSymbol('x', n + 1, n)).diagonal_length
n
When only one of the dimensions is symbolic the other will be
treated as though it is smaller:
>>> dtall = DiagonalOf(MatrixSymbol('x', n, 3))
>>> dtall.diagonal_length
3
When the size of the diagonal is not known, a value of None will
be returned:
>>> DiagonalOf(MatrixSymbol('x', n, m)).diagonal_length is None
True
"""
arg = property(lambda self: self.args[0])
@property
def shape(self):
r, c = self.arg.shape
if r.is_Integer and c.is_Integer:
m = min(r, c)
elif r.is_Integer and not c.is_Integer:
m = r
elif c.is_Integer and not r.is_Integer:
m = c
elif r == c:
m = r
else:
try:
m = min(r, c)
except TypeError:
m = None
return m, S.One
@property
def diagonal_length(self):
return self.shape[0]
def _entry(self, i, j, **kwargs):
return self.arg._entry(i, i, **kwargs)
class DiagMatrix(MatrixExpr):
"""
Turn a vector into a diagonal matrix.
"""
def __new__(cls, vector):
vector = _sympify(vector)
obj = MatrixExpr.__new__(cls, vector)
shape = vector.shape
dim = shape[1] if shape[0] == 1 else shape[0]
if vector.shape[0] != 1:
obj._iscolumn = True
else:
obj._iscolumn = False
obj._shape = (dim, dim)
obj._vector = vector
return obj
@property
def shape(self):
return self._shape
def _entry(self, i, j, **kwargs):
if self._iscolumn:
result = self._vector._entry(i, 0, **kwargs)
else:
result = self._vector._entry(0, j, **kwargs)
if i != j:
result *= KroneckerDelta(i, j)
return result
def _eval_transpose(self):
return self
def as_explicit(self):
from sympy.matrices.dense import diag
return diag(*list(self._vector.as_explicit()))
def doit(self, **hints):
from sympy.assumptions import ask, Q
from sympy.matrices.expressions.matmul import MatMul
from sympy.matrices.expressions.transpose import Transpose
from sympy.matrices.dense import eye
from sympy.matrices.matrixbase import MatrixBase
vector = self._vector
# This accounts for shape (1, 1) and identity matrices, among others:
if ask(Q.diagonal(vector)):
return vector
if isinstance(vector, MatrixBase):
ret = eye(max(vector.shape))
for i in range(ret.shape[0]):
ret[i, i] = vector[i]
return type(vector)(ret)
if vector.is_MatMul:
matrices = [arg for arg in vector.args if arg.is_Matrix]
scalars = [arg for arg in vector.args if arg not in matrices]
if scalars:
return Mul.fromiter(scalars)*DiagMatrix(MatMul.fromiter(matrices).doit()).doit()
if isinstance(vector, Transpose):
vector = vector.arg
return DiagMatrix(vector)
def diagonalize_vector(vector):
return DiagMatrix(vector).doit()
PK ]ZZZ��1w w ( sympy/matrices/expressions/dotproduct.pyfrom sympy.core import Basic, Expr
from sympy.core.sympify import _sympify
from sympy.matrices.expressions.transpose import transpose
class DotProduct(Expr):
"""
Dot product of vector matrices
The input should be two 1 x n or n x 1 matrices. The output represents the
scalar dotproduct.
This is similar to using MatrixElement and MatMul, except DotProduct does
not require that one vector to be a row vector and the other vector to be
a column vector.
>>> from sympy import MatrixSymbol, DotProduct
>>> A = MatrixSymbol('A', 1, 3)
>>> B = MatrixSymbol('B', 1, 3)
>>> DotProduct(A, B)
DotProduct(A, B)
>>> DotProduct(A, B).doit()
A[0, 0]*B[0, 0] + A[0, 1]*B[0, 1] + A[0, 2]*B[0, 2]
"""
def __new__(cls, arg1, arg2):
arg1, arg2 = _sympify((arg1, arg2))
if not arg1.is_Matrix:
raise TypeError("Argument 1 of DotProduct is not a matrix")
if not arg2.is_Matrix:
raise TypeError("Argument 2 of DotProduct is not a matrix")
if not (1 in arg1.shape):
raise TypeError("Argument 1 of DotProduct is not a vector")
if not (1 in arg2.shape):
raise TypeError("Argument 2 of DotProduct is not a vector")
if set(arg1.shape) != set(arg2.shape):
raise TypeError("DotProduct arguments are not the same length")
return Basic.__new__(cls, arg1, arg2)
def doit(self, expand=False, **hints):
if self.args[0].shape == self.args[1].shape:
if self.args[0].shape[0] == 1:
mul = self.args[0]*transpose(self.args[1])
else:
mul = transpose(self.args[0])*self.args[1]
else:
if self.args[0].shape[0] == 1:
mul = self.args[0]*self.args[1]
else:
mul = transpose(self.args[0])*transpose(self.args[1])
return mul[0]
PK ]ZZZs6�U� � , sympy/matrices/expressions/factorizations.pyfrom sympy.matrices.expressions import MatrixExpr
from sympy.assumptions.ask import Q
class Factorization(MatrixExpr):
arg = property(lambda self: self.args[0])
shape = property(lambda self: self.arg.shape) # type: ignore
class LofLU(Factorization):
@property
def predicates(self):
return (Q.lower_triangular,)
class UofLU(Factorization):
@property
def predicates(self):
return (Q.upper_triangular,)
class LofCholesky(LofLU): pass
class UofCholesky(UofLU): pass
class QofQR(Factorization):
@property
def predicates(self):
return (Q.orthogonal,)
class RofQR(Factorization):
@property
def predicates(self):
return (Q.upper_triangular,)
class EigenVectors(Factorization):
@property
def predicates(self):
return (Q.orthogonal,)
class EigenValues(Factorization):
@property
def predicates(self):
return (Q.diagonal,)
class UofSVD(Factorization):
@property
def predicates(self):
return (Q.orthogonal,)
class SofSVD(Factorization):
@property
def predicates(self):
return (Q.diagonal,)
class VofSVD(Factorization):
@property
def predicates(self):
return (Q.orthogonal,)
def lu(expr):
return LofLU(expr), UofLU(expr)
def qr(expr):
return QofQR(expr), RofQR(expr)
def eig(expr):
return EigenValues(expr), EigenVectors(expr)
def svd(expr):
return UofSVD(expr), SofSVD(expr), VofSVD(expr)
PK ]ZZZ��%`. . % sympy/matrices/expressions/fourier.pyfrom sympy.core.sympify import _sympify
from sympy.matrices.expressions import MatrixExpr
from sympy.core.numbers import I
from sympy.core.singleton import S
from sympy.functions.elementary.exponential import exp
from sympy.functions.elementary.miscellaneous import sqrt
class DFT(MatrixExpr):
r"""
Returns a discrete Fourier transform matrix. The matrix is scaled
with :math:`\frac{1}{\sqrt{n}}` so that it is unitary.
Parameters
==========
n : integer or Symbol
Size of the transform.
Examples
========
>>> from sympy.abc import n
>>> from sympy.matrices.expressions.fourier import DFT
>>> DFT(3)
DFT(3)
>>> DFT(3).as_explicit()
Matrix([
[sqrt(3)/3, sqrt(3)/3, sqrt(3)/3],
[sqrt(3)/3, sqrt(3)*exp(-2*I*pi/3)/3, sqrt(3)*exp(2*I*pi/3)/3],
[sqrt(3)/3, sqrt(3)*exp(2*I*pi/3)/3, sqrt(3)*exp(-2*I*pi/3)/3]])
>>> DFT(n).shape
(n, n)
References
==========
.. [1] https://en.wikipedia.org/wiki/DFT_matrix
"""
def __new__(cls, n):
n = _sympify(n)
cls._check_dim(n)
obj = super().__new__(cls, n)
return obj
n = property(lambda self: self.args[0]) # type: ignore
shape = property(lambda self: (self.n, self.n)) # type: ignore
def _entry(self, i, j, **kwargs):
w = exp(-2*S.Pi*I/self.n)
return w**(i*j) / sqrt(self.n)
def _eval_inverse(self):
return IDFT(self.n)
class IDFT(DFT):
r"""
Returns an inverse discrete Fourier transform matrix. The matrix is scaled
with :math:`\frac{1}{\sqrt{n}}` so that it is unitary.
Parameters
==========
n : integer or Symbol
Size of the transform
Examples
========
>>> from sympy.matrices.expressions.fourier import DFT, IDFT
>>> IDFT(3)
IDFT(3)
>>> IDFT(4)*DFT(4)
I
See Also
========
DFT
"""
def _entry(self, i, j, **kwargs):
w = exp(-2*S.Pi*I/self.n)
return w**(-i*j) / sqrt(self.n)
def _eval_inverse(self):
return DFT(self.n)
PK ]ZZZ�#��
�
( sympy/matrices/expressions/funcmatrix.pyfrom .matexpr import MatrixExpr
from sympy.core.function import FunctionClass, Lambda
from sympy.core.symbol import Dummy
from sympy.core.sympify import _sympify, sympify
from sympy.matrices import Matrix
from sympy.functions.elementary.complexes import re, im
class FunctionMatrix(MatrixExpr):
"""Represents a matrix using a function (``Lambda``) which gives
outputs according to the coordinates of each matrix entries.
Parameters
==========
rows : nonnegative integer. Can be symbolic.
cols : nonnegative integer. Can be symbolic.
lamda : Function, Lambda or str
If it is a SymPy ``Function`` or ``Lambda`` instance,
it should be able to accept two arguments which represents the
matrix coordinates.
If it is a pure string containing Python ``lambda`` semantics,
it is interpreted by the SymPy parser and casted into a SymPy
``Lambda`` instance.
Examples
========
Creating a ``FunctionMatrix`` from ``Lambda``:
>>> from sympy import FunctionMatrix, symbols, Lambda, MatPow
>>> i, j, n, m = symbols('i,j,n,m')
>>> FunctionMatrix(n, m, Lambda((i, j), i + j))
FunctionMatrix(n, m, Lambda((i, j), i + j))
Creating a ``FunctionMatrix`` from a SymPy function:
>>> from sympy import KroneckerDelta
>>> X = FunctionMatrix(3, 3, KroneckerDelta)
>>> X.as_explicit()
Matrix([
[1, 0, 0],
[0, 1, 0],
[0, 0, 1]])
Creating a ``FunctionMatrix`` from a SymPy undefined function:
>>> from sympy import Function
>>> f = Function('f')
>>> X = FunctionMatrix(3, 3, f)
>>> X.as_explicit()
Matrix([
[f(0, 0), f(0, 1), f(0, 2)],
[f(1, 0), f(1, 1), f(1, 2)],
[f(2, 0), f(2, 1), f(2, 2)]])
Creating a ``FunctionMatrix`` from Python ``lambda``:
>>> FunctionMatrix(n, m, 'lambda i, j: i + j')
FunctionMatrix(n, m, Lambda((i, j), i + j))
Example of lazy evaluation of matrix product:
>>> Y = FunctionMatrix(1000, 1000, Lambda((i, j), i + j))
>>> isinstance(Y*Y, MatPow) # this is an expression object
True
>>> (Y**2)[10,10] # So this is evaluated lazily
342923500
Notes
=====
This class provides an alternative way to represent an extremely
dense matrix with entries in some form of a sequence, in a most
sparse way.
"""
def __new__(cls, rows, cols, lamda):
rows, cols = _sympify(rows), _sympify(cols)
cls._check_dim(rows)
cls._check_dim(cols)
lamda = sympify(lamda)
if not isinstance(lamda, (FunctionClass, Lambda)):
raise ValueError(
"{} should be compatible with SymPy function classes."
.format(lamda))
if 2 not in lamda.nargs:
raise ValueError(
'{} should be able to accept 2 arguments.'.format(lamda))
if not isinstance(lamda, Lambda):
i, j = Dummy('i'), Dummy('j')
lamda = Lambda((i, j), lamda(i, j))
return super().__new__(cls, rows, cols, lamda)
@property
def shape(self):
return self.args[0:2]
@property
def lamda(self):
return self.args[2]
def _entry(self, i, j, **kwargs):
return self.lamda(i, j)
def _eval_trace(self):
from sympy.matrices.expressions.trace import Trace
from sympy.concrete.summations import Sum
return Trace(self).rewrite(Sum).doit()
def _eval_as_real_imag(self):
return (re(Matrix(self)), im(Matrix(self)))
PK ]ZZZ7�o�`6 `6 & sympy/matrices/expressions/hadamard.pyfrom collections import Counter
from sympy.core import Mul, sympify
from sympy.core.add import Add
from sympy.core.expr import ExprBuilder
from sympy.core.sorting import default_sort_key
from sympy.functions.elementary.exponential import log
from sympy.matrices.expressions.matexpr import MatrixExpr
from sympy.matrices.expressions._shape import validate_matadd_integer as validate
from sympy.matrices.expressions.special import ZeroMatrix, OneMatrix
from sympy.strategies import (
unpack, flatten, condition, exhaust, rm_id, sort
)
from sympy.utilities.exceptions import sympy_deprecation_warning
def hadamard_product(*matrices):
"""
Return the elementwise (aka Hadamard) product of matrices.
Examples
========
>>> from sympy import hadamard_product, MatrixSymbol
>>> A = MatrixSymbol('A', 2, 3)
>>> B = MatrixSymbol('B', 2, 3)
>>> hadamard_product(A)
A
>>> hadamard_product(A, B)
HadamardProduct(A, B)
>>> hadamard_product(A, B)[0, 1]
A[0, 1]*B[0, 1]
"""
if not matrices:
raise TypeError("Empty Hadamard product is undefined")
if len(matrices) == 1:
return matrices[0]
return HadamardProduct(*matrices).doit()
class HadamardProduct(MatrixExpr):
"""
Elementwise product of matrix expressions
Examples
========
Hadamard product for matrix symbols:
>>> from sympy import hadamard_product, HadamardProduct, MatrixSymbol
>>> A = MatrixSymbol('A', 5, 5)
>>> B = MatrixSymbol('B', 5, 5)
>>> isinstance(hadamard_product(A, B), HadamardProduct)
True
Notes
=====
This is a symbolic object that simply stores its argument without
evaluating it. To actually compute the product, use the function
``hadamard_product()`` or ``HadamardProduct.doit``
"""
is_HadamardProduct = True
def __new__(cls, *args, evaluate=False, check=None):
args = list(map(sympify, args))
if len(args) == 0:
# We currently don't have a way to support one-matrices of generic dimensions:
raise ValueError("HadamardProduct needs at least one argument")
if not all(isinstance(arg, MatrixExpr) for arg in args):
raise TypeError("Mix of Matrix and Scalar symbols")
if check is not None:
sympy_deprecation_warning(
"Passing check to HadamardProduct is deprecated and the check argument will be removed in a future version.",
deprecated_since_version="1.11",
active_deprecations_target='remove-check-argument-from-matrix-operations')
if check is not False:
validate(*args)
obj = super().__new__(cls, *args)
if evaluate:
obj = obj.doit(deep=False)
return obj
@property
def shape(self):
return self.args[0].shape
def _entry(self, i, j, **kwargs):
return Mul(*[arg._entry(i, j, **kwargs) for arg in self.args])
def _eval_transpose(self):
from sympy.matrices.expressions.transpose import transpose
return HadamardProduct(*list(map(transpose, self.args)))
def doit(self, **hints):
expr = self.func(*(i.doit(**hints) for i in self.args))
# Check for explicit matrices:
from sympy.matrices.matrixbase import MatrixBase
from sympy.matrices.immutable import ImmutableMatrix
explicit = [i for i in expr.args if isinstance(i, MatrixBase)]
if explicit:
remainder = [i for i in expr.args if i not in explicit]
expl_mat = ImmutableMatrix([
Mul.fromiter(i) for i in zip(*explicit)
]).reshape(*self.shape)
expr = HadamardProduct(*([expl_mat] + remainder))
return canonicalize(expr)
def _eval_derivative(self, x):
terms = []
args = list(self.args)
for i in range(len(args)):
factors = args[:i] + [args[i].diff(x)] + args[i+1:]
terms.append(hadamard_product(*factors))
return Add.fromiter(terms)
def _eval_derivative_matrix_lines(self, x):
from sympy.tensor.array.expressions.array_expressions import ArrayDiagonal
from sympy.tensor.array.expressions.array_expressions import ArrayTensorProduct
from sympy.matrices.expressions.matexpr import _make_matrix
with_x_ind = [i for i, arg in enumerate(self.args) if arg.has(x)]
lines = []
for ind in with_x_ind:
left_args = self.args[:ind]
right_args = self.args[ind+1:]
d = self.args[ind]._eval_derivative_matrix_lines(x)
hadam = hadamard_product(*(right_args + left_args))
diagonal = [(0, 2), (3, 4)]
diagonal = [e for j, e in enumerate(diagonal) if self.shape[j] != 1]
for i in d:
l1 = i._lines[i._first_line_index]
l2 = i._lines[i._second_line_index]
subexpr = ExprBuilder(
ArrayDiagonal,
[
ExprBuilder(
ArrayTensorProduct,
[
ExprBuilder(_make_matrix, [l1]),
hadam,
ExprBuilder(_make_matrix, [l2]),
]
),
*diagonal],
)
i._first_pointer_parent = subexpr.args[0].args[0].args
i._first_pointer_index = 0
i._second_pointer_parent = subexpr.args[0].args[2].args
i._second_pointer_index = 0
i._lines = [subexpr]
lines.append(i)
return lines
# TODO Implement algorithm for rewriting Hadamard product as diagonal matrix
# if matmul identy matrix is multiplied.
def canonicalize(x):
"""Canonicalize the Hadamard product ``x`` with mathematical properties.
Examples
========
>>> from sympy import MatrixSymbol, HadamardProduct
>>> from sympy import OneMatrix, ZeroMatrix
>>> from sympy.matrices.expressions.hadamard import canonicalize
>>> from sympy import init_printing
>>> init_printing(use_unicode=False)
>>> A = MatrixSymbol('A', 2, 2)
>>> B = MatrixSymbol('B', 2, 2)
>>> C = MatrixSymbol('C', 2, 2)
Hadamard product associativity:
>>> X = HadamardProduct(A, HadamardProduct(B, C))
>>> X
A.*(B.*C)
>>> canonicalize(X)
A.*B.*C
Hadamard product commutativity:
>>> X = HadamardProduct(A, B)
>>> Y = HadamardProduct(B, A)
>>> X
A.*B
>>> Y
B.*A
>>> canonicalize(X)
A.*B
>>> canonicalize(Y)
A.*B
Hadamard product identity:
>>> X = HadamardProduct(A, OneMatrix(2, 2))
>>> X
A.*1
>>> canonicalize(X)
A
Absorbing element of Hadamard product:
>>> X = HadamardProduct(A, ZeroMatrix(2, 2))
>>> X
A.*0
>>> canonicalize(X)
0
Rewriting to Hadamard Power
>>> X = HadamardProduct(A, A, A)
>>> X
A.*A.*A
>>> canonicalize(X)
.3
A
Notes
=====
As the Hadamard product is associative, nested products can be flattened.
The Hadamard product is commutative so that factors can be sorted for
canonical form.
A matrix of only ones is an identity for Hadamard product,
so every matrices of only ones can be removed.
Any zero matrix will make the whole product a zero matrix.
Duplicate elements can be collected and rewritten as HadamardPower
References
==========
.. [1] https://en.wikipedia.org/wiki/Hadamard_product_(matrices)
"""
# Associativity
rule = condition(
lambda x: isinstance(x, HadamardProduct),
flatten
)
fun = exhaust(rule)
x = fun(x)
# Identity
fun = condition(
lambda x: isinstance(x, HadamardProduct),
rm_id(lambda x: isinstance(x, OneMatrix))
)
x = fun(x)
# Absorbing by Zero Matrix
def absorb(x):
if any(isinstance(c, ZeroMatrix) for c in x.args):
return ZeroMatrix(*x.shape)
else:
return x
fun = condition(
lambda x: isinstance(x, HadamardProduct),
absorb
)
x = fun(x)
# Rewriting with HadamardPower
if isinstance(x, HadamardProduct):
tally = Counter(x.args)
new_arg = []
for base, exp in tally.items():
if exp == 1:
new_arg.append(base)
else:
new_arg.append(HadamardPower(base, exp))
x = HadamardProduct(*new_arg)
# Commutativity
fun = condition(
lambda x: isinstance(x, HadamardProduct),
sort(default_sort_key)
)
x = fun(x)
# Unpacking
x = unpack(x)
return x
def hadamard_power(base, exp):
base = sympify(base)
exp = sympify(exp)
if exp == 1:
return base
if not base.is_Matrix:
return base**exp
if exp.is_Matrix:
raise ValueError("cannot raise expression to a matrix")
return HadamardPower(base, exp)
class HadamardPower(MatrixExpr):
r"""
Elementwise power of matrix expressions
Parameters
==========
base : scalar or matrix
exp : scalar or matrix
Notes
=====
There are four definitions for the hadamard power which can be used.
Let's consider `A, B` as `(m, n)` matrices, and `a, b` as scalars.
Matrix raised to a scalar exponent:
.. math::
A^{\circ b} = \begin{bmatrix}
A_{0, 0}^b & A_{0, 1}^b & \cdots & A_{0, n-1}^b \\
A_{1, 0}^b & A_{1, 1}^b & \cdots & A_{1, n-1}^b \\
\vdots & \vdots & \ddots & \vdots \\
A_{m-1, 0}^b & A_{m-1, 1}^b & \cdots & A_{m-1, n-1}^b
\end{bmatrix}
Scalar raised to a matrix exponent:
.. math::
a^{\circ B} = \begin{bmatrix}
a^{B_{0, 0}} & a^{B_{0, 1}} & \cdots & a^{B_{0, n-1}} \\
a^{B_{1, 0}} & a^{B_{1, 1}} & \cdots & a^{B_{1, n-1}} \\
\vdots & \vdots & \ddots & \vdots \\
a^{B_{m-1, 0}} & a^{B_{m-1, 1}} & \cdots & a^{B_{m-1, n-1}}
\end{bmatrix}
Matrix raised to a matrix exponent:
.. math::
A^{\circ B} = \begin{bmatrix}
A_{0, 0}^{B_{0, 0}} & A_{0, 1}^{B_{0, 1}} &
\cdots & A_{0, n-1}^{B_{0, n-1}} \\
A_{1, 0}^{B_{1, 0}} & A_{1, 1}^{B_{1, 1}} &
\cdots & A_{1, n-1}^{B_{1, n-1}} \\
\vdots & \vdots &
\ddots & \vdots \\
A_{m-1, 0}^{B_{m-1, 0}} & A_{m-1, 1}^{B_{m-1, 1}} &
\cdots & A_{m-1, n-1}^{B_{m-1, n-1}}
\end{bmatrix}
Scalar raised to a scalar exponent:
.. math::
a^{\circ b} = a^b
"""
def __new__(cls, base, exp):
base = sympify(base)
exp = sympify(exp)
if base.is_scalar and exp.is_scalar:
return base ** exp
if isinstance(base, MatrixExpr) and isinstance(exp, MatrixExpr):
validate(base, exp)
obj = super().__new__(cls, base, exp)
return obj
@property
def base(self):
return self._args[0]
@property
def exp(self):
return self._args[1]
@property
def shape(self):
if self.base.is_Matrix:
return self.base.shape
return self.exp.shape
def _entry(self, i, j, **kwargs):
base = self.base
exp = self.exp
if base.is_Matrix:
a = base._entry(i, j, **kwargs)
elif base.is_scalar:
a = base
else:
raise ValueError(
'The base {} must be a scalar or a matrix.'.format(base))
if exp.is_Matrix:
b = exp._entry(i, j, **kwargs)
elif exp.is_scalar:
b = exp
else:
raise ValueError(
'The exponent {} must be a scalar or a matrix.'.format(exp))
return a ** b
def _eval_transpose(self):
from sympy.matrices.expressions.transpose import transpose
return HadamardPower(transpose(self.base), self.exp)
def _eval_derivative(self, x):
dexp = self.exp.diff(x)
logbase = self.base.applyfunc(log)
dlbase = logbase.diff(x)
return hadamard_product(
dexp*logbase + self.exp*dlbase,
self
)
def _eval_derivative_matrix_lines(self, x):
from sympy.tensor.array.expressions.array_expressions import ArrayTensorProduct
from sympy.tensor.array.expressions.array_expressions import ArrayDiagonal
from sympy.matrices.expressions.matexpr import _make_matrix
lr = self.base._eval_derivative_matrix_lines(x)
for i in lr:
diagonal = [(1, 2), (3, 4)]
diagonal = [e for j, e in enumerate(diagonal) if self.base.shape[j] != 1]
l1 = i._lines[i._first_line_index]
l2 = i._lines[i._second_line_index]
subexpr = ExprBuilder(
ArrayDiagonal,
[
ExprBuilder(
ArrayTensorProduct,
[
ExprBuilder(_make_matrix, [l1]),
self.exp*hadamard_power(self.base, self.exp-1),
ExprBuilder(_make_matrix, [l2]),
]
),
*diagonal],
validator=ArrayDiagonal._validate
)
i._first_pointer_parent = subexpr.args[0].args[0].args
i._first_pointer_index = 0
i._first_line_index = 0
i._second_pointer_parent = subexpr.args[0].args[2].args
i._second_pointer_index = 0
i._second_line_index = 0
i._lines = [subexpr]
return lr
PK ]ZZZtx�� � % sympy/matrices/expressions/inverse.pyfrom sympy.core.sympify import _sympify
from sympy.core import S, Basic
from sympy.matrices.exceptions import NonSquareMatrixError
from sympy.matrices.expressions.matpow import MatPow
class Inverse(MatPow):
"""
The multiplicative inverse of a matrix expression
This is a symbolic object that simply stores its argument without
evaluating it. To actually compute the inverse, use the ``.inverse()``
method of matrices.
Examples
========
>>> from sympy import MatrixSymbol, Inverse
>>> A = MatrixSymbol('A', 3, 3)
>>> B = MatrixSymbol('B', 3, 3)
>>> Inverse(A)
A**(-1)
>>> A.inverse() == Inverse(A)
True
>>> (A*B).inverse()
B**(-1)*A**(-1)
>>> Inverse(A*B)
(A*B)**(-1)
"""
is_Inverse = True
exp = S.NegativeOne
def __new__(cls, mat, exp=S.NegativeOne):
# exp is there to make it consistent with
# inverse.func(*inverse.args) == inverse
mat = _sympify(mat)
exp = _sympify(exp)
if not mat.is_Matrix:
raise TypeError("mat should be a matrix")
if mat.is_square is False:
raise NonSquareMatrixError("Inverse of non-square matrix %s" % mat)
return Basic.__new__(cls, mat, exp)
@property
def arg(self):
return self.args[0]
@property
def shape(self):
return self.arg.shape
def _eval_inverse(self):
return self.arg
def _eval_transpose(self):
return Inverse(self.arg.transpose())
def _eval_adjoint(self):
return Inverse(self.arg.adjoint())
def _eval_conjugate(self):
return Inverse(self.arg.conjugate())
def _eval_determinant(self):
from sympy.matrices.expressions.determinant import det
return 1/det(self.arg)
def doit(self, **hints):
if 'inv_expand' in hints and hints['inv_expand'] == False:
return self
arg = self.arg
if hints.get('deep', True):
arg = arg.doit(**hints)
return arg.inverse()
def _eval_derivative_matrix_lines(self, x):
arg = self.args[0]
lines = arg._eval_derivative_matrix_lines(x)
for line in lines:
line.first_pointer *= -self.T
line.second_pointer *= self
return lines
from sympy.assumptions.ask import ask, Q
from sympy.assumptions.refine import handlers_dict
def refine_Inverse(expr, assumptions):
"""
>>> from sympy import MatrixSymbol, Q, assuming, refine
>>> X = MatrixSymbol('X', 2, 2)
>>> X.I
X**(-1)
>>> with assuming(Q.orthogonal(X)):
... print(refine(X.I))
X.T
"""
if ask(Q.orthogonal(expr), assumptions):
return expr.arg.T
elif ask(Q.unitary(expr), assumptions):
return expr.arg.conjugate()
elif ask(Q.singular(expr), assumptions):
raise ValueError("Inverse of singular matrix %s" % expr.arg)
return expr
handlers_dict['Inverse'] = refine_Inverse
PK ]ZZZ*�^_\4 \4 ' sympy/matrices/expressions/kronecker.py"""Implementation of the Kronecker product"""
from functools import reduce
from math import prod
from sympy.core import Mul, sympify
from sympy.functions import adjoint
from sympy.matrices.exceptions import ShapeError
from sympy.matrices.expressions.matexpr import MatrixExpr
from sympy.matrices.expressions.transpose import transpose
from sympy.matrices.expressions.special import Identity
from sympy.matrices.matrixbase import MatrixBase
from sympy.strategies import (
canon, condition, distribute, do_one, exhaust, flatten, typed, unpack)
from sympy.strategies.traverse import bottom_up
from sympy.utilities import sift
from .matadd import MatAdd
from .matmul import MatMul
from .matpow import MatPow
def kronecker_product(*matrices):
"""
The Kronecker product of two or more arguments.
This computes the explicit Kronecker product for subclasses of
``MatrixBase`` i.e. explicit matrices. Otherwise, a symbolic
``KroneckerProduct`` object is returned.
Examples
========
For ``MatrixSymbol`` arguments a ``KroneckerProduct`` object is returned.
Elements of this matrix can be obtained by indexing, or for MatrixSymbols
with known dimension the explicit matrix can be obtained with
``.as_explicit()``
>>> from sympy import kronecker_product, MatrixSymbol
>>> A = MatrixSymbol('A', 2, 2)
>>> B = MatrixSymbol('B', 2, 2)
>>> kronecker_product(A)
A
>>> kronecker_product(A, B)
KroneckerProduct(A, B)
>>> kronecker_product(A, B)[0, 1]
A[0, 0]*B[0, 1]
>>> kronecker_product(A, B).as_explicit()
Matrix([
[A[0, 0]*B[0, 0], A[0, 0]*B[0, 1], A[0, 1]*B[0, 0], A[0, 1]*B[0, 1]],
[A[0, 0]*B[1, 0], A[0, 0]*B[1, 1], A[0, 1]*B[1, 0], A[0, 1]*B[1, 1]],
[A[1, 0]*B[0, 0], A[1, 0]*B[0, 1], A[1, 1]*B[0, 0], A[1, 1]*B[0, 1]],
[A[1, 0]*B[1, 0], A[1, 0]*B[1, 1], A[1, 1]*B[1, 0], A[1, 1]*B[1, 1]]])
For explicit matrices the Kronecker product is returned as a Matrix
>>> from sympy import Matrix, kronecker_product
>>> sigma_x = Matrix([
... [0, 1],
... [1, 0]])
...
>>> Isigma_y = Matrix([
... [0, 1],
... [-1, 0]])
...
>>> kronecker_product(sigma_x, Isigma_y)
Matrix([
[ 0, 0, 0, 1],
[ 0, 0, -1, 0],
[ 0, 1, 0, 0],
[-1, 0, 0, 0]])
See Also
========
KroneckerProduct
"""
if not matrices:
raise TypeError("Empty Kronecker product is undefined")
if len(matrices) == 1:
return matrices[0]
else:
return KroneckerProduct(*matrices).doit()
class KroneckerProduct(MatrixExpr):
"""
The Kronecker product of two or more arguments.
The Kronecker product is a non-commutative product of matrices.
Given two matrices of dimension (m, n) and (s, t) it produces a matrix
of dimension (m s, n t).
This is a symbolic object that simply stores its argument without
evaluating it. To actually compute the product, use the function
``kronecker_product()`` or call the ``.doit()`` or ``.as_explicit()``
methods.
>>> from sympy import KroneckerProduct, MatrixSymbol
>>> A = MatrixSymbol('A', 5, 5)
>>> B = MatrixSymbol('B', 5, 5)
>>> isinstance(KroneckerProduct(A, B), KroneckerProduct)
True
"""
is_KroneckerProduct = True
def __new__(cls, *args, check=True):
args = list(map(sympify, args))
if all(a.is_Identity for a in args):
ret = Identity(prod(a.rows for a in args))
if all(isinstance(a, MatrixBase) for a in args):
return ret.as_explicit()
else:
return ret
if check:
validate(*args)
return super().__new__(cls, *args)
@property
def shape(self):
rows, cols = self.args[0].shape
for mat in self.args[1:]:
rows *= mat.rows
cols *= mat.cols
return (rows, cols)
def _entry(self, i, j, **kwargs):
result = 1
for mat in reversed(self.args):
i, m = divmod(i, mat.rows)
j, n = divmod(j, mat.cols)
result *= mat[m, n]
return result
def _eval_adjoint(self):
return KroneckerProduct(*list(map(adjoint, self.args))).doit()
def _eval_conjugate(self):
return KroneckerProduct(*[a.conjugate() for a in self.args]).doit()
def _eval_transpose(self):
return KroneckerProduct(*list(map(transpose, self.args))).doit()
def _eval_trace(self):
from .trace import trace
return Mul(*[trace(a) for a in self.args])
def _eval_determinant(self):
from .determinant import det, Determinant
if not all(a.is_square for a in self.args):
return Determinant(self)
m = self.rows
return Mul(*[det(a)**(m/a.rows) for a in self.args])
def _eval_inverse(self):
try:
return KroneckerProduct(*[a.inverse() for a in self.args])
except ShapeError:
from sympy.matrices.expressions.inverse import Inverse
return Inverse(self)
def structurally_equal(self, other):
'''Determine whether two matrices have the same Kronecker product structure
Examples
========
>>> from sympy import KroneckerProduct, MatrixSymbol, symbols
>>> m, n = symbols(r'm, n', integer=True)
>>> A = MatrixSymbol('A', m, m)
>>> B = MatrixSymbol('B', n, n)
>>> C = MatrixSymbol('C', m, m)
>>> D = MatrixSymbol('D', n, n)
>>> KroneckerProduct(A, B).structurally_equal(KroneckerProduct(C, D))
True
>>> KroneckerProduct(A, B).structurally_equal(KroneckerProduct(D, C))
False
>>> KroneckerProduct(A, B).structurally_equal(C)
False
'''
# Inspired by BlockMatrix
return (isinstance(other, KroneckerProduct)
and self.shape == other.shape
and len(self.args) == len(other.args)
and all(a.shape == b.shape for (a, b) in zip(self.args, other.args)))
def has_matching_shape(self, other):
'''Determine whether two matrices have the appropriate structure to bring matrix
multiplication inside the KroneckerProdut
Examples
========
>>> from sympy import KroneckerProduct, MatrixSymbol, symbols
>>> m, n = symbols(r'm, n', integer=True)
>>> A = MatrixSymbol('A', m, n)
>>> B = MatrixSymbol('B', n, m)
>>> KroneckerProduct(A, B).has_matching_shape(KroneckerProduct(B, A))
True
>>> KroneckerProduct(A, B).has_matching_shape(KroneckerProduct(A, B))
False
>>> KroneckerProduct(A, B).has_matching_shape(A)
False
'''
return (isinstance(other, KroneckerProduct)
and self.cols == other.rows
and len(self.args) == len(other.args)
and all(a.cols == b.rows for (a, b) in zip(self.args, other.args)))
def _eval_expand_kroneckerproduct(self, **hints):
return flatten(canon(typed({KroneckerProduct: distribute(KroneckerProduct, MatAdd)}))(self))
def _kronecker_add(self, other):
if self.structurally_equal(other):
return self.__class__(*[a + b for (a, b) in zip(self.args, other.args)])
else:
return self + other
def _kronecker_mul(self, other):
if self.has_matching_shape(other):
return self.__class__(*[a*b for (a, b) in zip(self.args, other.args)])
else:
return self * other
def doit(self, **hints):
deep = hints.get('deep', True)
if deep:
args = [arg.doit(**hints) for arg in self.args]
else:
args = self.args
return canonicalize(KroneckerProduct(*args))
def validate(*args):
if not all(arg.is_Matrix for arg in args):
raise TypeError("Mix of Matrix and Scalar symbols")
# rules
def extract_commutative(kron):
c_part = []
nc_part = []
for arg in kron.args:
c, nc = arg.args_cnc()
c_part.extend(c)
nc_part.append(Mul._from_args(nc))
c_part = Mul(*c_part)
if c_part != 1:
return c_part*KroneckerProduct(*nc_part)
return kron
def matrix_kronecker_product(*matrices):
"""Compute the Kronecker product of a sequence of SymPy Matrices.
This is the standard Kronecker product of matrices [1].
Parameters
==========
matrices : tuple of MatrixBase instances
The matrices to take the Kronecker product of.
Returns
=======
matrix : MatrixBase
The Kronecker product matrix.
Examples
========
>>> from sympy import Matrix
>>> from sympy.matrices.expressions.kronecker import (
... matrix_kronecker_product)
>>> m1 = Matrix([[1,2],[3,4]])
>>> m2 = Matrix([[1,0],[0,1]])
>>> matrix_kronecker_product(m1, m2)
Matrix([
[1, 0, 2, 0],
[0, 1, 0, 2],
[3, 0, 4, 0],
[0, 3, 0, 4]])
>>> matrix_kronecker_product(m2, m1)
Matrix([
[1, 2, 0, 0],
[3, 4, 0, 0],
[0, 0, 1, 2],
[0, 0, 3, 4]])
References
==========
.. [1] https://en.wikipedia.org/wiki/Kronecker_product
"""
# Make sure we have a sequence of Matrices
if not all(isinstance(m, MatrixBase) for m in matrices):
raise TypeError(
'Sequence of Matrices expected, got: %s' % repr(matrices)
)
# Pull out the first element in the product.
matrix_expansion = matrices[-1]
# Do the kronecker product working from right to left.
for mat in reversed(matrices[:-1]):
rows = mat.rows
cols = mat.cols
# Go through each row appending kronecker product to.
# running matrix_expansion.
for i in range(rows):
start = matrix_expansion*mat[i*cols]
# Go through each column joining each item
for j in range(cols - 1):
start = start.row_join(
matrix_expansion*mat[i*cols + j + 1]
)
# If this is the first element, make it the start of the
# new row.
if i == 0:
next = start
else:
next = next.col_join(start)
matrix_expansion = next
MatrixClass = max(matrices, key=lambda M: M._class_priority).__class__
if isinstance(matrix_expansion, MatrixClass):
return matrix_expansion
else:
return MatrixClass(matrix_expansion)
def explicit_kronecker_product(kron):
# Make sure we have a sequence of Matrices
if not all(isinstance(m, MatrixBase) for m in kron.args):
return kron
return matrix_kronecker_product(*kron.args)
rules = (unpack,
explicit_kronecker_product,
flatten,
extract_commutative)
canonicalize = exhaust(condition(lambda x: isinstance(x, KroneckerProduct),
do_one(*rules)))
def _kronecker_dims_key(expr):
if isinstance(expr, KroneckerProduct):
return tuple(a.shape for a in expr.args)
else:
return (0,)
def kronecker_mat_add(expr):
args = sift(expr.args, _kronecker_dims_key)
nonkrons = args.pop((0,), None)
if not args:
return expr
krons = [reduce(lambda x, y: x._kronecker_add(y), group)
for group in args.values()]
if not nonkrons:
return MatAdd(*krons)
else:
return MatAdd(*krons) + nonkrons
def kronecker_mat_mul(expr):
# modified from block matrix code
factor, matrices = expr.as_coeff_matrices()
i = 0
while i < len(matrices) - 1:
A, B = matrices[i:i+2]
if isinstance(A, KroneckerProduct) and isinstance(B, KroneckerProduct):
matrices[i] = A._kronecker_mul(B)
matrices.pop(i+1)
else:
i += 1
return factor*MatMul(*matrices)
def kronecker_mat_pow(expr):
if isinstance(expr.base, KroneckerProduct) and all(a.is_square for a in expr.base.args):
return KroneckerProduct(*[MatPow(a, expr.exp) for a in expr.base.args])
else:
return expr
def combine_kronecker(expr):
"""Combine KronekeckerProduct with expression.
If possible write operations on KroneckerProducts of compatible shapes
as a single KroneckerProduct.
Examples
========
>>> from sympy.matrices.expressions import combine_kronecker
>>> from sympy import MatrixSymbol, KroneckerProduct, symbols
>>> m, n = symbols(r'm, n', integer=True)
>>> A = MatrixSymbol('A', m, n)
>>> B = MatrixSymbol('B', n, m)
>>> combine_kronecker(KroneckerProduct(A, B)*KroneckerProduct(B, A))
KroneckerProduct(A*B, B*A)
>>> combine_kronecker(KroneckerProduct(A, B)+KroneckerProduct(B.T, A.T))
KroneckerProduct(A + B.T, B + A.T)
>>> C = MatrixSymbol('C', n, n)
>>> D = MatrixSymbol('D', m, m)
>>> combine_kronecker(KroneckerProduct(C, D)**m)
KroneckerProduct(C**m, D**m)
"""
def haskron(expr):
return isinstance(expr, MatrixExpr) and expr.has(KroneckerProduct)
rule = exhaust(
bottom_up(exhaust(condition(haskron, typed(
{MatAdd: kronecker_mat_add,
MatMul: kronecker_mat_mul,
MatPow: kronecker_mat_pow})))))
result = rule(expr)
doit = getattr(result, 'doit', None)
if doit is not None:
return doit()
else:
return result
PK ]ZZZ��� � $ sympy/matrices/expressions/matadd.pyfrom functools import reduce
import operator
from sympy.core import Basic, sympify
from sympy.core.add import add, Add, _could_extract_minus_sign
from sympy.core.sorting import default_sort_key
from sympy.functions import adjoint
from sympy.matrices.matrixbase import MatrixBase
from sympy.matrices.expressions.transpose import transpose
from sympy.strategies import (rm_id, unpack, flatten, sort, condition,
exhaust, do_one, glom)
from sympy.matrices.expressions.matexpr import MatrixExpr
from sympy.matrices.expressions.special import ZeroMatrix, GenericZeroMatrix
from sympy.matrices.expressions._shape import validate_matadd_integer as validate
from sympy.utilities.iterables import sift
from sympy.utilities.exceptions import sympy_deprecation_warning
# XXX: MatAdd should perhaps not subclass directly from Add
class MatAdd(MatrixExpr, Add):
"""A Sum of Matrix Expressions
MatAdd inherits from and operates like SymPy Add
Examples
========
>>> from sympy import MatAdd, MatrixSymbol
>>> A = MatrixSymbol('A', 5, 5)
>>> B = MatrixSymbol('B', 5, 5)
>>> C = MatrixSymbol('C', 5, 5)
>>> MatAdd(A, B, C)
A + B + C
"""
is_MatAdd = True
identity = GenericZeroMatrix()
def __new__(cls, *args, evaluate=False, check=None, _sympify=True):
if not args:
return cls.identity
# This must be removed aggressively in the constructor to avoid
# TypeErrors from GenericZeroMatrix().shape
args = list(filter(lambda i: cls.identity != i, args))
if _sympify:
args = list(map(sympify, args))
if not all(isinstance(arg, MatrixExpr) for arg in args):
raise TypeError("Mix of Matrix and Scalar symbols")
obj = Basic.__new__(cls, *args)
if check is not None:
sympy_deprecation_warning(
"Passing check to MatAdd is deprecated and the check argument will be removed in a future version.",
deprecated_since_version="1.11",
active_deprecations_target='remove-check-argument-from-matrix-operations')
if check is not False:
validate(*args)
if evaluate:
obj = cls._evaluate(obj)
return obj
@classmethod
def _evaluate(cls, expr):
return canonicalize(expr)
@property
def shape(self):
return self.args[0].shape
def could_extract_minus_sign(self):
return _could_extract_minus_sign(self)
def expand(self, **kwargs):
expanded = super(MatAdd, self).expand(**kwargs)
return self._evaluate(expanded)
def _entry(self, i, j, **kwargs):
return Add(*[arg._entry(i, j, **kwargs) for arg in self.args])
def _eval_transpose(self):
return MatAdd(*[transpose(arg) for arg in self.args]).doit()
def _eval_adjoint(self):
return MatAdd(*[adjoint(arg) for arg in self.args]).doit()
def _eval_trace(self):
from .trace import trace
return Add(*[trace(arg) for arg in self.args]).doit()
def doit(self, **hints):
deep = hints.get('deep', True)
if deep:
args = [arg.doit(**hints) for arg in self.args]
else:
args = self.args
return canonicalize(MatAdd(*args))
def _eval_derivative_matrix_lines(self, x):
add_lines = [arg._eval_derivative_matrix_lines(x) for arg in self.args]
return [j for i in add_lines for j in i]
add.register_handlerclass((Add, MatAdd), MatAdd)
factor_of = lambda arg: arg.as_coeff_mmul()[0]
matrix_of = lambda arg: unpack(arg.as_coeff_mmul()[1])
def combine(cnt, mat):
if cnt == 1:
return mat
else:
return cnt * mat
def merge_explicit(matadd):
""" Merge explicit MatrixBase arguments
Examples
========
>>> from sympy import MatrixSymbol, eye, Matrix, MatAdd, pprint
>>> from sympy.matrices.expressions.matadd import merge_explicit
>>> A = MatrixSymbol('A', 2, 2)
>>> B = eye(2)
>>> C = Matrix([[1, 2], [3, 4]])
>>> X = MatAdd(A, B, C)
>>> pprint(X)
[1 0] [1 2]
A + [ ] + [ ]
[0 1] [3 4]
>>> pprint(merge_explicit(X))
[2 2]
A + [ ]
[3 5]
"""
groups = sift(matadd.args, lambda arg: isinstance(arg, MatrixBase))
if len(groups[True]) > 1:
return MatAdd(*(groups[False] + [reduce(operator.add, groups[True])]))
else:
return matadd
rules = (rm_id(lambda x: x == 0 or isinstance(x, ZeroMatrix)),
unpack,
flatten,
glom(matrix_of, factor_of, combine),
merge_explicit,
sort(default_sort_key))
canonicalize = exhaust(condition(lambda x: isinstance(x, MatAdd),
do_one(*rules)))
PK ]ZZZ�n �k �k % sympy/matrices/expressions/matexpr.pyfrom __future__ import annotations
from functools import wraps
from sympy.core import S, Integer, Basic, Mul, Add
from sympy.core.assumptions import check_assumptions
from sympy.core.decorators import call_highest_priority
from sympy.core.expr import Expr, ExprBuilder
from sympy.core.logic import FuzzyBool
from sympy.core.symbol import Str, Dummy, symbols, Symbol
from sympy.core.sympify import SympifyError, _sympify
from sympy.external.gmpy import SYMPY_INTS
from sympy.functions import conjugate, adjoint
from sympy.functions.special.tensor_functions import KroneckerDelta
from sympy.matrices.exceptions import NonSquareMatrixError
from sympy.matrices.kind import MatrixKind
from sympy.matrices.matrixbase import MatrixBase
from sympy.multipledispatch import dispatch
from sympy.utilities.misc import filldedent
def _sympifyit(arg, retval=None):
# This version of _sympifyit sympifies MutableMatrix objects
def deco(func):
@wraps(func)
def __sympifyit_wrapper(a, b):
try:
b = _sympify(b)
return func(a, b)
except SympifyError:
return retval
return __sympifyit_wrapper
return deco
class MatrixExpr(Expr):
"""Superclass for Matrix Expressions
MatrixExprs represent abstract matrices, linear transformations represented
within a particular basis.
Examples
========
>>> from sympy import MatrixSymbol
>>> A = MatrixSymbol('A', 3, 3)
>>> y = MatrixSymbol('y', 3, 1)
>>> x = (A.T*A).I * A * y
See Also
========
MatrixSymbol, MatAdd, MatMul, Transpose, Inverse
"""
__slots__: tuple[str, ...] = ()
# Should not be considered iterable by the
# sympy.utilities.iterables.iterable function. Subclass that actually are
# iterable (i.e., explicit matrices) should set this to True.
_iterable = False
_op_priority = 11.0
is_Matrix: bool = True
is_MatrixExpr: bool = True
is_Identity: FuzzyBool = None
is_Inverse = False
is_Transpose = False
is_ZeroMatrix = False
is_MatAdd = False
is_MatMul = False
is_commutative = False
is_number = False
is_symbol = False
is_scalar = False
kind: MatrixKind = MatrixKind()
def __new__(cls, *args, **kwargs):
args = map(_sympify, args)
return Basic.__new__(cls, *args, **kwargs)
# The following is adapted from the core Expr object
@property
def shape(self) -> tuple[Expr, Expr]:
raise NotImplementedError
@property
def _add_handler(self):
return MatAdd
@property
def _mul_handler(self):
return MatMul
def __neg__(self):
return MatMul(S.NegativeOne, self).doit()
def __abs__(self):
raise NotImplementedError
@_sympifyit('other', NotImplemented)
@call_highest_priority('__radd__')
def __add__(self, other):
return MatAdd(self, other).doit()
@_sympifyit('other', NotImplemented)
@call_highest_priority('__add__')
def __radd__(self, other):
return MatAdd(other, self).doit()
@_sympifyit('other', NotImplemented)
@call_highest_priority('__rsub__')
def __sub__(self, other):
return MatAdd(self, -other).doit()
@_sympifyit('other', NotImplemented)
@call_highest_priority('__sub__')
def __rsub__(self, other):
return MatAdd(other, -self).doit()
@_sympifyit('other', NotImplemented)
@call_highest_priority('__rmul__')
def __mul__(self, other):
return MatMul(self, other).doit()
@_sympifyit('other', NotImplemented)
@call_highest_priority('__rmul__')
def __matmul__(self, other):
return MatMul(self, other).doit()
@_sympifyit('other', NotImplemented)
@call_highest_priority('__mul__')
def __rmul__(self, other):
return MatMul(other, self).doit()
@_sympifyit('other', NotImplemented)
@call_highest_priority('__mul__')
def __rmatmul__(self, other):
return MatMul(other, self).doit()
@_sympifyit('other', NotImplemented)
@call_highest_priority('__rpow__')
def __pow__(self, other):
return MatPow(self, other).doit()
@_sympifyit('other', NotImplemented)
@call_highest_priority('__pow__')
def __rpow__(self, other):
raise NotImplementedError("Matrix Power not defined")
@_sympifyit('other', NotImplemented)
@call_highest_priority('__rtruediv__')
def __truediv__(self, other):
return self * other**S.NegativeOne
@_sympifyit('other', NotImplemented)
@call_highest_priority('__truediv__')
def __rtruediv__(self, other):
raise NotImplementedError()
#return MatMul(other, Pow(self, S.NegativeOne))
@property
def rows(self):
return self.shape[0]
@property
def cols(self):
return self.shape[1]
@property
def is_square(self) -> bool | None:
rows, cols = self.shape
if isinstance(rows, Integer) and isinstance(cols, Integer):
return rows == cols
if rows == cols:
return True
return None
def _eval_conjugate(self):
from sympy.matrices.expressions.adjoint import Adjoint
return Adjoint(Transpose(self))
def as_real_imag(self, deep=True, **hints):
return self._eval_as_real_imag()
def _eval_as_real_imag(self):
real = S.Half * (self + self._eval_conjugate())
im = (self - self._eval_conjugate())/(2*S.ImaginaryUnit)
return (real, im)
def _eval_inverse(self):
return Inverse(self)
def _eval_determinant(self):
return Determinant(self)
def _eval_transpose(self):
return Transpose(self)
def _eval_trace(self):
return None
def _eval_power(self, exp):
"""
Override this in sub-classes to implement simplification of powers. The cases where the exponent
is -1, 0, 1 are already covered in MatPow.doit(), so implementations can exclude these cases.
"""
return MatPow(self, exp)
def _eval_simplify(self, **kwargs):
if self.is_Atom:
return self
else:
from sympy.simplify import simplify
return self.func(*[simplify(x, **kwargs) for x in self.args])
def _eval_adjoint(self):
from sympy.matrices.expressions.adjoint import Adjoint
return Adjoint(self)
def _eval_derivative_n_times(self, x, n):
return Basic._eval_derivative_n_times(self, x, n)
def _eval_derivative(self, x):
# `x` is a scalar:
if self.has(x):
# See if there are other methods using it:
return super()._eval_derivative(x)
else:
return ZeroMatrix(*self.shape)
@classmethod
def _check_dim(cls, dim):
"""Helper function to check invalid matrix dimensions"""
ok = not dim.is_Float and check_assumptions(
dim, integer=True, nonnegative=True)
if ok is False:
raise ValueError(
"The dimension specification {} should be "
"a nonnegative integer.".format(dim))
def _entry(self, i, j, **kwargs):
raise NotImplementedError(
"Indexing not implemented for %s" % self.__class__.__name__)
def adjoint(self):
return adjoint(self)
def as_coeff_Mul(self, rational=False):
"""Efficiently extract the coefficient of a product."""
return S.One, self
def conjugate(self):
return conjugate(self)
def transpose(self):
from sympy.matrices.expressions.transpose import transpose
return transpose(self)
@property
def T(self):
'''Matrix transposition'''
return self.transpose()
def inverse(self):
if self.is_square is False:
raise NonSquareMatrixError('Inverse of non-square matrix')
return self._eval_inverse()
def inv(self):
return self.inverse()
def det(self):
from sympy.matrices.expressions.determinant import det
return det(self)
@property
def I(self):
return self.inverse()
def valid_index(self, i, j):
def is_valid(idx):
return isinstance(idx, (int, Integer, Symbol, Expr))
return (is_valid(i) and is_valid(j) and
(self.rows is None or
(i >= -self.rows) != False and (i < self.rows) != False) and
(j >= -self.cols) != False and (j < self.cols) != False)
def __getitem__(self, key):
if not isinstance(key, tuple) and isinstance(key, slice):
from sympy.matrices.expressions.slice import MatrixSlice
return MatrixSlice(self, key, (0, None, 1))
if isinstance(key, tuple) and len(key) == 2:
i, j = key
if isinstance(i, slice) or isinstance(j, slice):
from sympy.matrices.expressions.slice import MatrixSlice
return MatrixSlice(self, i, j)
i, j = _sympify(i), _sympify(j)
if self.valid_index(i, j) != False:
return self._entry(i, j)
else:
raise IndexError("Invalid indices (%s, %s)" % (i, j))
elif isinstance(key, (SYMPY_INTS, Integer)):
# row-wise decomposition of matrix
rows, cols = self.shape
# allow single indexing if number of columns is known
if not isinstance(cols, Integer):
raise IndexError(filldedent('''
Single indexing is only supported when the number
of columns is known.'''))
key = _sympify(key)
i = key // cols
j = key % cols
if self.valid_index(i, j) != False:
return self._entry(i, j)
else:
raise IndexError("Invalid index %s" % key)
elif isinstance(key, (Symbol, Expr)):
raise IndexError(filldedent('''
Only integers may be used when addressing the matrix
with a single index.'''))
raise IndexError("Invalid index, wanted %s[i,j]" % self)
def _is_shape_symbolic(self) -> bool:
return (not isinstance(self.rows, (SYMPY_INTS, Integer))
or not isinstance(self.cols, (SYMPY_INTS, Integer)))
def as_explicit(self):
"""
Returns a dense Matrix with elements represented explicitly
Returns an object of type ImmutableDenseMatrix.
Examples
========
>>> from sympy import Identity
>>> I = Identity(3)
>>> I
I
>>> I.as_explicit()
Matrix([
[1, 0, 0],
[0, 1, 0],
[0, 0, 1]])
See Also
========
as_mutable: returns mutable Matrix type
"""
if self._is_shape_symbolic():
raise ValueError(
'Matrix with symbolic shape '
'cannot be represented explicitly.')
from sympy.matrices.immutable import ImmutableDenseMatrix
return ImmutableDenseMatrix([[self[i, j]
for j in range(self.cols)]
for i in range(self.rows)])
def as_mutable(self):
"""
Returns a dense, mutable matrix with elements represented explicitly
Examples
========
>>> from sympy import Identity
>>> I = Identity(3)
>>> I
I
>>> I.shape
(3, 3)
>>> I.as_mutable()
Matrix([
[1, 0, 0],
[0, 1, 0],
[0, 0, 1]])
See Also
========
as_explicit: returns ImmutableDenseMatrix
"""
return self.as_explicit().as_mutable()
def __array__(self, dtype=object, copy=None):
if copy is not None and not copy:
raise TypeError("Cannot implement copy=False when converting Matrix to ndarray")
from numpy import empty
a = empty(self.shape, dtype=object)
for i in range(self.rows):
for j in range(self.cols):
a[i, j] = self[i, j]
return a
def equals(self, other):
"""
Test elementwise equality between matrices, potentially of different
types
>>> from sympy import Identity, eye
>>> Identity(3).equals(eye(3))
True
"""
return self.as_explicit().equals(other)
def canonicalize(self):
return self
def as_coeff_mmul(self):
return S.One, MatMul(self)
@staticmethod
def from_index_summation(expr, first_index=None, last_index=None, dimensions=None):
r"""
Parse expression of matrices with explicitly summed indices into a
matrix expression without indices, if possible.
This transformation expressed in mathematical notation:
`\sum_{j=0}^{N-1} A_{i,j} B_{j,k} \Longrightarrow \mathbf{A}\cdot \mathbf{B}`
Optional parameter ``first_index``: specify which free index to use as
the index starting the expression.
Examples
========
>>> from sympy import MatrixSymbol, MatrixExpr, Sum
>>> from sympy.abc import i, j, k, l, N
>>> A = MatrixSymbol("A", N, N)
>>> B = MatrixSymbol("B", N, N)
>>> expr = Sum(A[i, j]*B[j, k], (j, 0, N-1))
>>> MatrixExpr.from_index_summation(expr)
A*B
Transposition is detected:
>>> expr = Sum(A[j, i]*B[j, k], (j, 0, N-1))
>>> MatrixExpr.from_index_summation(expr)
A.T*B
Detect the trace:
>>> expr = Sum(A[i, i], (i, 0, N-1))
>>> MatrixExpr.from_index_summation(expr)
Trace(A)
More complicated expressions:
>>> expr = Sum(A[i, j]*B[k, j]*A[l, k], (j, 0, N-1), (k, 0, N-1))
>>> MatrixExpr.from_index_summation(expr)
A*B.T*A.T
"""
from sympy.tensor.array.expressions.from_indexed_to_array import convert_indexed_to_array
from sympy.tensor.array.expressions.from_array_to_matrix import convert_array_to_matrix
first_indices = []
if first_index is not None:
first_indices.append(first_index)
if last_index is not None:
first_indices.append(last_index)
arr = convert_indexed_to_array(expr, first_indices=first_indices)
return convert_array_to_matrix(arr)
def applyfunc(self, func):
from .applyfunc import ElementwiseApplyFunction
return ElementwiseApplyFunction(func, self)
@dispatch(MatrixExpr, Expr)
def _eval_is_eq(lhs, rhs): # noqa:F811
return False
@dispatch(MatrixExpr, MatrixExpr) # type: ignore
def _eval_is_eq(lhs, rhs): # noqa:F811
if lhs.shape != rhs.shape:
return False
if (lhs - rhs).is_ZeroMatrix:
return True
def get_postprocessor(cls):
def _postprocessor(expr):
# To avoid circular imports, we can't have MatMul/MatAdd on the top level
mat_class = {Mul: MatMul, Add: MatAdd}[cls]
nonmatrices = []
matrices = []
for term in expr.args:
if isinstance(term, MatrixExpr):
matrices.append(term)
else:
nonmatrices.append(term)
if not matrices:
return cls._from_args(nonmatrices)
if nonmatrices:
if cls == Mul:
for i in range(len(matrices)):
if not matrices[i].is_MatrixExpr:
# If one of the matrices explicit, absorb the scalar into it
# (doit will combine all explicit matrices into one, so it
# doesn't matter which)
matrices[i] = matrices[i].__mul__(cls._from_args(nonmatrices))
nonmatrices = []
break
else:
# Maintain the ability to create Add(scalar, matrix) without
# raising an exception. That way different algorithms can
# replace matrix expressions with non-commutative symbols to
# manipulate them like non-commutative scalars.
return cls._from_args(nonmatrices + [mat_class(*matrices).doit(deep=False)])
if mat_class == MatAdd:
return mat_class(*matrices).doit(deep=False)
return mat_class(cls._from_args(nonmatrices), *matrices).doit(deep=False)
return _postprocessor
Basic._constructor_postprocessor_mapping[MatrixExpr] = {
"Mul": [get_postprocessor(Mul)],
"Add": [get_postprocessor(Add)],
}
def _matrix_derivative(expr, x, old_algorithm=False):
if isinstance(expr, MatrixBase) or isinstance(x, MatrixBase):
# Do not use array expressions for explicit matrices:
old_algorithm = True
if old_algorithm:
return _matrix_derivative_old_algorithm(expr, x)
from sympy.tensor.array.expressions.from_matrix_to_array import convert_matrix_to_array
from sympy.tensor.array.expressions.arrayexpr_derivatives import array_derive
from sympy.tensor.array.expressions.from_array_to_matrix import convert_array_to_matrix
array_expr = convert_matrix_to_array(expr)
diff_array_expr = array_derive(array_expr, x)
diff_matrix_expr = convert_array_to_matrix(diff_array_expr)
return diff_matrix_expr
def _matrix_derivative_old_algorithm(expr, x):
from sympy.tensor.array.array_derivatives import ArrayDerivative
lines = expr._eval_derivative_matrix_lines(x)
parts = [i.build() for i in lines]
from sympy.tensor.array.expressions.from_array_to_matrix import convert_array_to_matrix
parts = [[convert_array_to_matrix(j) for j in i] for i in parts]
def _get_shape(elem):
if isinstance(elem, MatrixExpr):
return elem.shape
return 1, 1
def get_rank(parts):
return sum(j not in (1, None) for i in parts for j in _get_shape(i))
ranks = [get_rank(i) for i in parts]
rank = ranks[0]
def contract_one_dims(parts):
if len(parts) == 1:
return parts[0]
else:
p1, p2 = parts[:2]
if p2.is_Matrix:
p2 = p2.T
if p1 == Identity(1):
pbase = p2
elif p2 == Identity(1):
pbase = p1
else:
pbase = p1*p2
if len(parts) == 2:
return pbase
else: # len(parts) > 2
if pbase.is_Matrix:
raise ValueError("")
return pbase*Mul.fromiter(parts[2:])
if rank <= 2:
return Add.fromiter([contract_one_dims(i) for i in parts])
return ArrayDerivative(expr, x)
class MatrixElement(Expr):
parent = property(lambda self: self.args[0])
i = property(lambda self: self.args[1])
j = property(lambda self: self.args[2])
_diff_wrt = True
is_symbol = True
is_commutative = True
def __new__(cls, name, n, m):
n, m = map(_sympify, (n, m))
if isinstance(name, str):
name = Symbol(name)
else:
if isinstance(name, MatrixBase):
if n.is_Integer and m.is_Integer:
return name[n, m]
name = _sympify(name) # change mutable into immutable
else:
name = _sympify(name)
if not isinstance(name.kind, MatrixKind):
raise TypeError("First argument of MatrixElement should be a matrix")
if not getattr(name, 'valid_index', lambda n, m: True)(n, m):
raise IndexError('indices out of range')
obj = Expr.__new__(cls, name, n, m)
return obj
@property
def symbol(self):
return self.args[0]
def doit(self, **hints):
deep = hints.get('deep', True)
if deep:
args = [arg.doit(**hints) for arg in self.args]
else:
args = self.args
return args[0][args[1], args[2]]
@property
def indices(self):
return self.args[1:]
def _eval_derivative(self, v):
if not isinstance(v, MatrixElement):
return self.parent.diff(v)[self.i, self.j]
M = self.args[0]
m, n = self.parent.shape
if M == v.args[0]:
return KroneckerDelta(self.args[1], v.args[1], (0, m-1)) * \
KroneckerDelta(self.args[2], v.args[2], (0, n-1))
if isinstance(M, Inverse):
from sympy.concrete.summations import Sum
i, j = self.args[1:]
i1, i2 = symbols("z1, z2", cls=Dummy)
Y = M.args[0]
r1, r2 = Y.shape
return -Sum(M[i, i1]*Y[i1, i2].diff(v)*M[i2, j], (i1, 0, r1-1), (i2, 0, r2-1))
if self.has(v.args[0]):
return None
return S.Zero
class MatrixSymbol(MatrixExpr):
"""Symbolic representation of a Matrix object
Creates a SymPy Symbol to represent a Matrix. This matrix has a shape and
can be included in Matrix Expressions
Examples
========
>>> from sympy import MatrixSymbol, Identity
>>> A = MatrixSymbol('A', 3, 4) # A 3 by 4 Matrix
>>> B = MatrixSymbol('B', 4, 3) # A 4 by 3 Matrix
>>> A.shape
(3, 4)
>>> 2*A*B + Identity(3)
I + 2*A*B
"""
is_commutative = False
is_symbol = True
_diff_wrt = True
def __new__(cls, name, n, m):
n, m = _sympify(n), _sympify(m)
cls._check_dim(m)
cls._check_dim(n)
if isinstance(name, str):
name = Str(name)
obj = Basic.__new__(cls, name, n, m)
return obj
@property
def shape(self):
return self.args[1], self.args[2]
@property
def name(self):
return self.args[0].name
def _entry(self, i, j, **kwargs):
return MatrixElement(self, i, j)
@property
def free_symbols(self):
return {self}
def _eval_simplify(self, **kwargs):
return self
def _eval_derivative(self, x):
# x is a scalar:
return ZeroMatrix(self.shape[0], self.shape[1])
def _eval_derivative_matrix_lines(self, x):
if self != x:
first = ZeroMatrix(x.shape[0], self.shape[0]) if self.shape[0] != 1 else S.Zero
second = ZeroMatrix(x.shape[1], self.shape[1]) if self.shape[1] != 1 else S.Zero
return [_LeftRightArgs(
[first, second],
)]
else:
first = Identity(self.shape[0]) if self.shape[0] != 1 else S.One
second = Identity(self.shape[1]) if self.shape[1] != 1 else S.One
return [_LeftRightArgs(
[first, second],
)]
def matrix_symbols(expr):
return [sym for sym in expr.free_symbols if sym.is_Matrix]
class _LeftRightArgs:
r"""
Helper class to compute matrix derivatives.
The logic: when an expression is derived by a matrix `X_{mn}`, two lines of
matrix multiplications are created: the one contracted to `m` (first line),
and the one contracted to `n` (second line).
Transposition flips the side by which new matrices are connected to the
lines.
The trace connects the end of the two lines.
"""
def __init__(self, lines, higher=S.One):
self._lines = list(lines)
self._first_pointer_parent = self._lines
self._first_pointer_index = 0
self._first_line_index = 0
self._second_pointer_parent = self._lines
self._second_pointer_index = 1
self._second_line_index = 1
self.higher = higher
@property
def first_pointer(self):
return self._first_pointer_parent[self._first_pointer_index]
@first_pointer.setter
def first_pointer(self, value):
self._first_pointer_parent[self._first_pointer_index] = value
@property
def second_pointer(self):
return self._second_pointer_parent[self._second_pointer_index]
@second_pointer.setter
def second_pointer(self, value):
self._second_pointer_parent[self._second_pointer_index] = value
def __repr__(self):
built = [self._build(i) for i in self._lines]
return "_LeftRightArgs(lines=%s, higher=%s)" % (
built,
self.higher,
)
def transpose(self):
self._first_pointer_parent, self._second_pointer_parent = self._second_pointer_parent, self._first_pointer_parent
self._first_pointer_index, self._second_pointer_index = self._second_pointer_index, self._first_pointer_index
self._first_line_index, self._second_line_index = self._second_line_index, self._first_line_index
return self
@staticmethod
def _build(expr):
if isinstance(expr, ExprBuilder):
return expr.build()
if isinstance(expr, list):
if len(expr) == 1:
return expr[0]
else:
return expr[0](*[_LeftRightArgs._build(i) for i in expr[1]])
else:
return expr
def build(self):
data = [self._build(i) for i in self._lines]
if self.higher != 1:
data += [self._build(self.higher)]
data = list(data)
return data
def matrix_form(self):
if self.first != 1 and self.higher != 1:
raise ValueError("higher dimensional array cannot be represented")
def _get_shape(elem):
if isinstance(elem, MatrixExpr):
return elem.shape
return (None, None)
if _get_shape(self.first)[1] != _get_shape(self.second)[1]:
# Remove one-dimensional identity matrices:
# (this is needed by `a.diff(a)` where `a` is a vector)
if _get_shape(self.second) == (1, 1):
return self.first*self.second[0, 0]
if _get_shape(self.first) == (1, 1):
return self.first[1, 1]*self.second.T
raise ValueError("incompatible shapes")
if self.first != 1:
return self.first*self.second.T
else:
return self.higher
def rank(self):
"""
Number of dimensions different from trivial (warning: not related to
matrix rank).
"""
rank = 0
if self.first != 1:
rank += sum(i != 1 for i in self.first.shape)
if self.second != 1:
rank += sum(i != 1 for i in self.second.shape)
if self.higher != 1:
rank += 2
return rank
def _multiply_pointer(self, pointer, other):
from ...tensor.array.expressions.array_expressions import ArrayTensorProduct
from ...tensor.array.expressions.array_expressions import ArrayContraction
subexpr = ExprBuilder(
ArrayContraction,
[
ExprBuilder(
ArrayTensorProduct,
[
pointer,
other
]
),
(1, 2)
],
validator=ArrayContraction._validate
)
return subexpr
def append_first(self, other):
self.first_pointer *= other
def append_second(self, other):
self.second_pointer *= other
def _make_matrix(x):
from sympy.matrices.immutable import ImmutableDenseMatrix
if isinstance(x, MatrixExpr):
return x
return ImmutableDenseMatrix([[x]])
from .matmul import MatMul
from .matadd import MatAdd
from .matpow import MatPow
from .transpose import Transpose
from .inverse import Inverse
from .special import ZeroMatrix, Identity
from .determinant import Determinant
PK ]ZZZ���%�< �< $ sympy/matrices/expressions/matmul.pyfrom sympy.assumptions.ask import ask, Q
from sympy.assumptions.refine import handlers_dict
from sympy.core import Basic, sympify, S
from sympy.core.mul import mul, Mul
from sympy.core.numbers import Number, Integer
from sympy.core.symbol import Dummy
from sympy.functions import adjoint
from sympy.strategies import (rm_id, unpack, typed, flatten, exhaust,
do_one, new)
from sympy.matrices.exceptions import NonInvertibleMatrixError
from sympy.matrices.matrixbase import MatrixBase
from sympy.utilities.exceptions import sympy_deprecation_warning
from sympy.matrices.expressions._shape import validate_matmul_integer as validate
from .inverse import Inverse
from .matexpr import MatrixExpr
from .matpow import MatPow
from .transpose import transpose
from .permutation import PermutationMatrix
from .special import ZeroMatrix, Identity, GenericIdentity, OneMatrix
# XXX: MatMul should perhaps not subclass directly from Mul
class MatMul(MatrixExpr, Mul):
"""
A product of matrix expressions
Examples
========
>>> from sympy import MatMul, MatrixSymbol
>>> A = MatrixSymbol('A', 5, 4)
>>> B = MatrixSymbol('B', 4, 3)
>>> C = MatrixSymbol('C', 3, 6)
>>> MatMul(A, B, C)
A*B*C
"""
is_MatMul = True
identity = GenericIdentity()
def __new__(cls, *args, evaluate=False, check=None, _sympify=True):
if not args:
return cls.identity
# This must be removed aggressively in the constructor to avoid
# TypeErrors from GenericIdentity().shape
args = list(filter(lambda i: cls.identity != i, args))
if _sympify:
args = list(map(sympify, args))
obj = Basic.__new__(cls, *args)
factor, matrices = obj.as_coeff_matrices()
if check is not None:
sympy_deprecation_warning(
"Passing check to MatMul is deprecated and the check argument will be removed in a future version.",
deprecated_since_version="1.11",
active_deprecations_target='remove-check-argument-from-matrix-operations')
if check is not False:
validate(*matrices)
if not matrices:
# Should it be
#
# return Basic.__neq__(cls, factor, GenericIdentity()) ?
return factor
if evaluate:
return cls._evaluate(obj)
return obj
@classmethod
def _evaluate(cls, expr):
return canonicalize(expr)
@property
def shape(self):
matrices = [arg for arg in self.args if arg.is_Matrix]
return (matrices[0].rows, matrices[-1].cols)
def _entry(self, i, j, expand=True, **kwargs):
# Avoid cyclic imports
from sympy.concrete.summations import Sum
from sympy.matrices.immutable import ImmutableMatrix
coeff, matrices = self.as_coeff_matrices()
if len(matrices) == 1: # situation like 2*X, matmul is just X
return coeff * matrices[0][i, j]
indices = [None]*(len(matrices) + 1)
ind_ranges = [None]*(len(matrices) - 1)
indices[0] = i
indices[-1] = j
def f():
counter = 1
while True:
yield Dummy("i_%i" % counter)
counter += 1
dummy_generator = kwargs.get("dummy_generator", f())
for i in range(1, len(matrices)):
indices[i] = next(dummy_generator)
for i, arg in enumerate(matrices[:-1]):
ind_ranges[i] = arg.shape[1] - 1
matrices = [arg._entry(indices[i], indices[i+1], dummy_generator=dummy_generator) for i, arg in enumerate(matrices)]
expr_in_sum = Mul.fromiter(matrices)
if any(v.has(ImmutableMatrix) for v in matrices):
expand = True
result = coeff*Sum(
expr_in_sum,
*zip(indices[1:-1], [0]*len(ind_ranges), ind_ranges)
)
# Don't waste time in result.doit() if the sum bounds are symbolic
if not any(isinstance(v, (Integer, int)) for v in ind_ranges):
expand = False
return result.doit() if expand else result
def as_coeff_matrices(self):
scalars = [x for x in self.args if not x.is_Matrix]
matrices = [x for x in self.args if x.is_Matrix]
coeff = Mul(*scalars)
if coeff.is_commutative is False:
raise NotImplementedError("noncommutative scalars in MatMul are not supported.")
return coeff, matrices
def as_coeff_mmul(self):
coeff, matrices = self.as_coeff_matrices()
return coeff, MatMul(*matrices)
def expand(self, **kwargs):
expanded = super(MatMul, self).expand(**kwargs)
return self._evaluate(expanded)
def _eval_transpose(self):
"""Transposition of matrix multiplication.
Notes
=====
The following rules are applied.
Transposition for matrix multiplied with another matrix:
`\\left(A B\\right)^{T} = B^{T} A^{T}`
Transposition for matrix multiplied with scalar:
`\\left(c A\\right)^{T} = c A^{T}`
References
==========
.. [1] https://en.wikipedia.org/wiki/Transpose
"""
coeff, matrices = self.as_coeff_matrices()
return MatMul(
coeff, *[transpose(arg) for arg in matrices[::-1]]).doit()
def _eval_adjoint(self):
return MatMul(*[adjoint(arg) for arg in self.args[::-1]]).doit()
def _eval_trace(self):
factor, mmul = self.as_coeff_mmul()
if factor != 1:
from .trace import trace
return factor * trace(mmul.doit())
def _eval_determinant(self):
from sympy.matrices.expressions.determinant import Determinant
factor, matrices = self.as_coeff_matrices()
square_matrices = only_squares(*matrices)
return factor**self.rows * Mul(*list(map(Determinant, square_matrices)))
def _eval_inverse(self):
if all(arg.is_square for arg in self.args if isinstance(arg, MatrixExpr)):
return MatMul(*(
arg.inverse() if isinstance(arg, MatrixExpr) else arg**-1
for arg in self.args[::-1]
)
).doit()
return Inverse(self)
def doit(self, **hints):
deep = hints.get('deep', True)
if deep:
args = tuple(arg.doit(**hints) for arg in self.args)
else:
args = self.args
# treat scalar*MatrixSymbol or scalar*MatPow separately
expr = canonicalize(MatMul(*args))
return expr
# Needed for partial compatibility with Mul
def args_cnc(self, cset=False, warn=True, **kwargs):
coeff_c = [x for x in self.args if x.is_commutative]
coeff_nc = [x for x in self.args if not x.is_commutative]
if cset:
clen = len(coeff_c)
coeff_c = set(coeff_c)
if clen and warn and len(coeff_c) != clen:
raise ValueError('repeated commutative arguments: %s' %
[ci for ci in coeff_c if list(self.args).count(ci) > 1])
return [coeff_c, coeff_nc]
def _eval_derivative_matrix_lines(self, x):
from .transpose import Transpose
with_x_ind = [i for i, arg in enumerate(self.args) if arg.has(x)]
lines = []
for ind in with_x_ind:
left_args = self.args[:ind]
right_args = self.args[ind+1:]
if right_args:
right_mat = MatMul.fromiter(right_args)
else:
right_mat = Identity(self.shape[1])
if left_args:
left_rev = MatMul.fromiter([Transpose(i).doit() if i.is_Matrix else i for i in reversed(left_args)])
else:
left_rev = Identity(self.shape[0])
d = self.args[ind]._eval_derivative_matrix_lines(x)
for i in d:
i.append_first(left_rev)
i.append_second(right_mat)
lines.append(i)
return lines
mul.register_handlerclass((Mul, MatMul), MatMul)
# Rules
def newmul(*args):
if args[0] == 1:
args = args[1:]
return new(MatMul, *args)
def any_zeros(mul):
if any(arg.is_zero or (arg.is_Matrix and arg.is_ZeroMatrix)
for arg in mul.args):
matrices = [arg for arg in mul.args if arg.is_Matrix]
return ZeroMatrix(matrices[0].rows, matrices[-1].cols)
return mul
def merge_explicit(matmul):
""" Merge explicit MatrixBase arguments
>>> from sympy import MatrixSymbol, Matrix, MatMul, pprint
>>> from sympy.matrices.expressions.matmul import merge_explicit
>>> A = MatrixSymbol('A', 2, 2)
>>> B = Matrix([[1, 1], [1, 1]])
>>> C = Matrix([[1, 2], [3, 4]])
>>> X = MatMul(A, B, C)
>>> pprint(X)
[1 1] [1 2]
A*[ ]*[ ]
[1 1] [3 4]
>>> pprint(merge_explicit(X))
[4 6]
A*[ ]
[4 6]
>>> X = MatMul(B, A, C)
>>> pprint(X)
[1 1] [1 2]
[ ]*A*[ ]
[1 1] [3 4]
>>> pprint(merge_explicit(X))
[1 1] [1 2]
[ ]*A*[ ]
[1 1] [3 4]
"""
if not any(isinstance(arg, MatrixBase) for arg in matmul.args):
return matmul
newargs = []
last = matmul.args[0]
for arg in matmul.args[1:]:
if isinstance(arg, (MatrixBase, Number)) and isinstance(last, (MatrixBase, Number)):
last = last * arg
else:
newargs.append(last)
last = arg
newargs.append(last)
return MatMul(*newargs)
def remove_ids(mul):
""" Remove Identities from a MatMul
This is a modified version of sympy.strategies.rm_id.
This is necesssary because MatMul may contain both MatrixExprs and Exprs
as args.
See Also
========
sympy.strategies.rm_id
"""
# Separate Exprs from MatrixExprs in args
factor, mmul = mul.as_coeff_mmul()
# Apply standard rm_id for MatMuls
result = rm_id(lambda x: x.is_Identity is True)(mmul)
if result != mmul:
return newmul(factor, *result.args) # Recombine and return
else:
return mul
def factor_in_front(mul):
factor, matrices = mul.as_coeff_matrices()
if factor != 1:
return newmul(factor, *matrices)
return mul
def combine_powers(mul):
r"""Combine consecutive powers with the same base into one, e.g.
$$A \times A^2 \Rightarrow A^3$$
This also cancels out the possible matrix inverses using the
knowledgebase of :class:`~.Inverse`, e.g.,
$$ Y \times X \times X^{-1} \Rightarrow Y $$
"""
factor, args = mul.as_coeff_matrices()
new_args = [args[0]]
for i in range(1, len(args)):
A = new_args[-1]
B = args[i]
if isinstance(B, Inverse) and isinstance(B.arg, MatMul):
Bargs = B.arg.args
l = len(Bargs)
if list(Bargs) == new_args[-l:]:
new_args = new_args[:-l] + [Identity(B.shape[0])]
continue
if isinstance(A, Inverse) and isinstance(A.arg, MatMul):
Aargs = A.arg.args
l = len(Aargs)
if list(Aargs) == args[i:i+l]:
identity = Identity(A.shape[0])
new_args[-1] = identity
for j in range(i, i+l):
args[j] = identity
continue
if A.is_square == False or B.is_square == False:
new_args.append(B)
continue
if isinstance(A, MatPow):
A_base, A_exp = A.args
else:
A_base, A_exp = A, S.One
if isinstance(B, MatPow):
B_base, B_exp = B.args
else:
B_base, B_exp = B, S.One
if A_base == B_base:
new_exp = A_exp + B_exp
new_args[-1] = MatPow(A_base, new_exp).doit(deep=False)
continue
elif not isinstance(B_base, MatrixBase):
try:
B_base_inv = B_base.inverse()
except NonInvertibleMatrixError:
B_base_inv = None
if B_base_inv is not None and A_base == B_base_inv:
new_exp = A_exp - B_exp
new_args[-1] = MatPow(A_base, new_exp).doit(deep=False)
continue
new_args.append(B)
return newmul(factor, *new_args)
def combine_permutations(mul):
"""Refine products of permutation matrices as the products of cycles.
"""
args = mul.args
l = len(args)
if l < 2:
return mul
result = [args[0]]
for i in range(1, l):
A = result[-1]
B = args[i]
if isinstance(A, PermutationMatrix) and \
isinstance(B, PermutationMatrix):
cycle_1 = A.args[0]
cycle_2 = B.args[0]
result[-1] = PermutationMatrix(cycle_1 * cycle_2)
else:
result.append(B)
return MatMul(*result)
def combine_one_matrices(mul):
"""
Combine products of OneMatrix
e.g. OneMatrix(2, 3) * OneMatrix(3, 4) -> 3 * OneMatrix(2, 4)
"""
factor, args = mul.as_coeff_matrices()
new_args = [args[0]]
for B in args[1:]:
A = new_args[-1]
if not isinstance(A, OneMatrix) or not isinstance(B, OneMatrix):
new_args.append(B)
continue
new_args.pop()
new_args.append(OneMatrix(A.shape[0], B.shape[1]))
factor *= A.shape[1]
return newmul(factor, *new_args)
def distribute_monom(mul):
"""
Simplify MatMul expressions but distributing
rational term to MatMul.
e.g. 2*(A+B) -> 2*A + 2*B
"""
args = mul.args
if len(args) == 2:
from .matadd import MatAdd
if args[0].is_MatAdd and args[1].is_Rational:
return MatAdd(*[MatMul(mat, args[1]).doit() for mat in args[0].args])
if args[1].is_MatAdd and args[0].is_Rational:
return MatAdd(*[MatMul(args[0], mat).doit() for mat in args[1].args])
return mul
rules = (
distribute_monom, any_zeros, remove_ids, combine_one_matrices, combine_powers, unpack, rm_id(lambda x: x == 1),
merge_explicit, factor_in_front, flatten, combine_permutations)
canonicalize = exhaust(typed({MatMul: do_one(*rules)}))
def only_squares(*matrices):
"""factor matrices only if they are square"""
if matrices[0].rows != matrices[-1].cols:
raise RuntimeError("Invalid matrices being multiplied")
out = []
start = 0
for i, M in enumerate(matrices):
if M.cols == matrices[start].rows:
out.append(MatMul(*matrices[start:i+1]).doit())
start = i+1
return out
def refine_MatMul(expr, assumptions):
"""
>>> from sympy import MatrixSymbol, Q, assuming, refine
>>> X = MatrixSymbol('X', 2, 2)
>>> expr = X * X.T
>>> print(expr)
X*X.T
>>> with assuming(Q.orthogonal(X)):
... print(refine(expr))
I
"""
newargs = []
exprargs = []
for args in expr.args:
if args.is_Matrix:
exprargs.append(args)
else:
newargs.append(args)
last = exprargs[0]
for arg in exprargs[1:]:
if arg == last.T and ask(Q.orthogonal(arg), assumptions):
last = Identity(arg.shape[0])
elif arg == last.conjugate() and ask(Q.unitary(arg), assumptions):
last = Identity(arg.shape[0])
else:
newargs.append(last)
last = arg
newargs.append(last)
return MatMul(*newargs)
handlers_dict['MatMul'] = refine_MatMul
PK ]ZZZ�zT $ sympy/matrices/expressions/matpow.pyfrom .matexpr import MatrixExpr
from .special import Identity
from sympy.core import S
from sympy.core.expr import ExprBuilder
from sympy.core.cache import cacheit
from sympy.core.power import Pow
from sympy.core.sympify import _sympify
from sympy.matrices import MatrixBase
from sympy.matrices.exceptions import NonSquareMatrixError
class MatPow(MatrixExpr):
def __new__(cls, base, exp, evaluate=False, **options):
base = _sympify(base)
if not base.is_Matrix:
raise TypeError("MatPow base should be a matrix")
if base.is_square is False:
raise NonSquareMatrixError("Power of non-square matrix %s" % base)
exp = _sympify(exp)
obj = super().__new__(cls, base, exp)
if evaluate:
obj = obj.doit(deep=False)
return obj
@property
def base(self):
return self.args[0]
@property
def exp(self):
return self.args[1]
@property
def shape(self):
return self.base.shape
@cacheit
def _get_explicit_matrix(self):
return self.base.as_explicit()**self.exp
def _entry(self, i, j, **kwargs):
from sympy.matrices.expressions import MatMul
A = self.doit()
if isinstance(A, MatPow):
# We still have a MatPow, make an explicit MatMul out of it.
if A.exp.is_Integer and A.exp.is_positive:
A = MatMul(*[A.base for k in range(A.exp)])
elif not self._is_shape_symbolic():
return A._get_explicit_matrix()[i, j]
else:
# Leave the expression unevaluated:
from sympy.matrices.expressions.matexpr import MatrixElement
return MatrixElement(self, i, j)
return A[i, j]
def doit(self, **hints):
if hints.get('deep', True):
base, exp = (arg.doit(**hints) for arg in self.args)
else:
base, exp = self.args
# combine all powers, e.g. (A ** 2) ** 3 -> A ** 6
while isinstance(base, MatPow):
exp *= base.args[1]
base = base.args[0]
if isinstance(base, MatrixBase):
# Delegate
return base ** exp
# Handle simple cases so that _eval_power() in MatrixExpr sub-classes can ignore them
if exp == S.One:
return base
if exp == S.Zero:
return Identity(base.rows)
if exp == S.NegativeOne:
from sympy.matrices.expressions import Inverse
return Inverse(base).doit(**hints)
eval_power = getattr(base, '_eval_power', None)
if eval_power is not None:
return eval_power(exp)
return MatPow(base, exp)
def _eval_transpose(self):
base, exp = self.args
return MatPow(base.transpose(), exp)
def _eval_adjoint(self):
base, exp = self.args
return MatPow(base.adjoint(), exp)
def _eval_conjugate(self):
base, exp = self.args
return MatPow(base.conjugate(), exp)
def _eval_derivative(self, x):
return Pow._eval_derivative(self, x)
def _eval_derivative_matrix_lines(self, x):
from sympy.tensor.array.expressions.array_expressions import ArrayContraction
from ...tensor.array.expressions.array_expressions import ArrayTensorProduct
from .matmul import MatMul
from .inverse import Inverse
exp = self.exp
if self.base.shape == (1, 1) and not exp.has(x):
lr = self.base._eval_derivative_matrix_lines(x)
for i in lr:
subexpr = ExprBuilder(
ArrayContraction,
[
ExprBuilder(
ArrayTensorProduct,
[
Identity(1),
i._lines[0],
exp*self.base**(exp-1),
i._lines[1],
Identity(1),
]
),
(0, 3, 4), (5, 7, 8)
],
validator=ArrayContraction._validate
)
i._first_pointer_parent = subexpr.args[0].args
i._first_pointer_index = 0
i._second_pointer_parent = subexpr.args[0].args
i._second_pointer_index = 4
i._lines = [subexpr]
return lr
if (exp > 0) == True:
newexpr = MatMul.fromiter([self.base for i in range(exp)])
elif (exp == -1) == True:
return Inverse(self.base)._eval_derivative_matrix_lines(x)
elif (exp < 0) == True:
newexpr = MatMul.fromiter([Inverse(self.base) for i in range(-exp)])
elif (exp == 0) == True:
return self.doit()._eval_derivative_matrix_lines(x)
else:
raise NotImplementedError("cannot evaluate %s derived by %s" % (self, x))
return newexpr._eval_derivative_matrix_lines(x)
def _eval_inverse(self):
return MatPow(self.base, -self.exp)
PK ]ZZZf��r r ) sympy/matrices/expressions/permutation.pyfrom sympy.core import S
from sympy.core.sympify import _sympify
from sympy.functions import KroneckerDelta
from .matexpr import MatrixExpr
from .special import ZeroMatrix, Identity, OneMatrix
class PermutationMatrix(MatrixExpr):
"""A Permutation Matrix
Parameters
==========
perm : Permutation
The permutation the matrix uses.
The size of the permutation determines the matrix size.
See the documentation of
:class:`sympy.combinatorics.permutations.Permutation` for
the further information of how to create a permutation object.
Examples
========
>>> from sympy import Matrix, PermutationMatrix
>>> from sympy.combinatorics import Permutation
Creating a permutation matrix:
>>> p = Permutation(1, 2, 0)
>>> P = PermutationMatrix(p)
>>> P = P.as_explicit()
>>> P
Matrix([
[0, 1, 0],
[0, 0, 1],
[1, 0, 0]])
Permuting a matrix row and column:
>>> M = Matrix([0, 1, 2])
>>> Matrix(P*M)
Matrix([
[1],
[2],
[0]])
>>> Matrix(M.T*P)
Matrix([[2, 0, 1]])
See Also
========
sympy.combinatorics.permutations.Permutation
"""
def __new__(cls, perm):
from sympy.combinatorics.permutations import Permutation
perm = _sympify(perm)
if not isinstance(perm, Permutation):
raise ValueError(
"{} must be a SymPy Permutation instance.".format(perm))
return super().__new__(cls, perm)
@property
def shape(self):
size = self.args[0].size
return (size, size)
@property
def is_Identity(self):
return self.args[0].is_Identity
def doit(self, **hints):
if self.is_Identity:
return Identity(self.rows)
return self
def _entry(self, i, j, **kwargs):
perm = self.args[0]
return KroneckerDelta(perm.apply(i), j)
def _eval_power(self, exp):
return PermutationMatrix(self.args[0] ** exp).doit()
def _eval_inverse(self):
return PermutationMatrix(self.args[0] ** -1)
_eval_transpose = _eval_adjoint = _eval_inverse
def _eval_determinant(self):
sign = self.args[0].signature()
if sign == 1:
return S.One
elif sign == -1:
return S.NegativeOne
raise NotImplementedError
def _eval_rewrite_as_BlockDiagMatrix(self, *args, **kwargs):
from sympy.combinatorics.permutations import Permutation
from .blockmatrix import BlockDiagMatrix
perm = self.args[0]
full_cyclic_form = perm.full_cyclic_form
cycles_picks = []
# Stage 1. Decompose the cycles into the blockable form.
a, b, c = 0, 0, 0
flag = False
for cycle in full_cyclic_form:
l = len(cycle)
m = max(cycle)
if not flag:
if m + 1 > a + l:
flag = True
temp = [cycle]
b = m
c = l
else:
cycles_picks.append([cycle])
a += l
else:
if m > b:
if m + 1 == a + c + l:
temp.append(cycle)
cycles_picks.append(temp)
flag = False
a = m+1
else:
b = m
temp.append(cycle)
c += l
else:
if b + 1 == a + c + l:
temp.append(cycle)
cycles_picks.append(temp)
flag = False
a = b+1
else:
temp.append(cycle)
c += l
# Stage 2. Normalize each decomposed cycles and build matrix.
p = 0
args = []
for pick in cycles_picks:
new_cycles = []
l = 0
for cycle in pick:
new_cycle = [i - p for i in cycle]
new_cycles.append(new_cycle)
l += len(cycle)
p += l
perm = Permutation(new_cycles)
mat = PermutationMatrix(perm)
args.append(mat)
return BlockDiagMatrix(*args)
class MatrixPermute(MatrixExpr):
r"""Symbolic representation for permuting matrix rows or columns.
Parameters
==========
perm : Permutation, PermutationMatrix
The permutation to use for permuting the matrix.
The permutation can be resized to the suitable one,
axis : 0 or 1
The axis to permute alongside.
If `0`, it will permute the matrix rows.
If `1`, it will permute the matrix columns.
Notes
=====
This follows the same notation used in
:meth:`sympy.matrices.matrixbase.MatrixBase.permute`.
Examples
========
>>> from sympy import Matrix, MatrixPermute
>>> from sympy.combinatorics import Permutation
Permuting the matrix rows:
>>> p = Permutation(1, 2, 0)
>>> A = Matrix([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
>>> B = MatrixPermute(A, p, axis=0)
>>> B.as_explicit()
Matrix([
[4, 5, 6],
[7, 8, 9],
[1, 2, 3]])
Permuting the matrix columns:
>>> B = MatrixPermute(A, p, axis=1)
>>> B.as_explicit()
Matrix([
[2, 3, 1],
[5, 6, 4],
[8, 9, 7]])
See Also
========
sympy.matrices.matrixbase.MatrixBase.permute
"""
def __new__(cls, mat, perm, axis=S.Zero):
from sympy.combinatorics.permutations import Permutation
mat = _sympify(mat)
if not mat.is_Matrix:
raise ValueError(
"{} must be a SymPy matrix instance.".format(perm))
perm = _sympify(perm)
if isinstance(perm, PermutationMatrix):
perm = perm.args[0]
if not isinstance(perm, Permutation):
raise ValueError(
"{} must be a SymPy Permutation or a PermutationMatrix " \
"instance".format(perm))
axis = _sympify(axis)
if axis not in (0, 1):
raise ValueError("The axis must be 0 or 1.")
mat_size = mat.shape[axis]
if mat_size != perm.size:
try:
perm = perm.resize(mat_size)
except ValueError:
raise ValueError(
"Size does not match between the permutation {} "
"and the matrix {} threaded over the axis {} "
"and cannot be converted."
.format(perm, mat, axis))
return super().__new__(cls, mat, perm, axis)
def doit(self, deep=True, **hints):
mat, perm, axis = self.args
if deep:
mat = mat.doit(deep=deep, **hints)
perm = perm.doit(deep=deep, **hints)
if perm.is_Identity:
return mat
if mat.is_Identity:
if axis is S.Zero:
return PermutationMatrix(perm)
elif axis is S.One:
return PermutationMatrix(perm**-1)
if isinstance(mat, (ZeroMatrix, OneMatrix)):
return mat
if isinstance(mat, MatrixPermute) and mat.args[2] == axis:
return MatrixPermute(mat.args[0], perm * mat.args[1], axis)
return self
@property
def shape(self):
return self.args[0].shape
def _entry(self, i, j, **kwargs):
mat, perm, axis = self.args
if axis == 0:
return mat[perm.apply(i), j]
elif axis == 1:
return mat[i, perm.apply(j)]
def _eval_rewrite_as_MatMul(self, *args, **kwargs):
from .matmul import MatMul
mat, perm, axis = self.args
deep = kwargs.get("deep", True)
if deep:
mat = mat.rewrite(MatMul)
if axis == 0:
return MatMul(PermutationMatrix(perm), mat)
elif axis == 1:
return MatMul(mat, PermutationMatrix(perm**-1))
PK ]ZZZLb*�� � " sympy/matrices/expressions/sets.pyfrom sympy.core.assumptions import check_assumptions
from sympy.core.logic import fuzzy_and
from sympy.core.sympify import _sympify
from sympy.matrices.kind import MatrixKind
from sympy.sets.sets import Set, SetKind
from sympy.core.kind import NumberKind
from .matexpr import MatrixExpr
class MatrixSet(Set):
"""
MatrixSet represents the set of matrices with ``shape = (n, m)`` over the
given set.
Examples
========
>>> from sympy.matrices import MatrixSet
>>> from sympy import S, I, Matrix
>>> M = MatrixSet(2, 2, set=S.Reals)
>>> X = Matrix([[1, 2], [3, 4]])
>>> X in M
True
>>> X = Matrix([[1, 2], [I, 4]])
>>> X in M
False
"""
is_empty = False
def __new__(cls, n, m, set):
n, m, set = _sympify(n), _sympify(m), _sympify(set)
cls._check_dim(n)
cls._check_dim(m)
if not isinstance(set, Set):
raise TypeError("{} should be an instance of Set.".format(set))
return Set.__new__(cls, n, m, set)
@property
def shape(self):
return self.args[:2]
@property
def set(self):
return self.args[2]
def _contains(self, other):
if not isinstance(other, MatrixExpr):
raise TypeError("{} should be an instance of MatrixExpr.".format(other))
if other.shape != self.shape:
are_symbolic = any(_sympify(x).is_Symbol for x in other.shape + self.shape)
if are_symbolic:
return None
return False
return fuzzy_and(self.set.contains(x) for x in other)
@classmethod
def _check_dim(cls, dim):
"""Helper function to check invalid matrix dimensions"""
ok = not dim.is_Float and check_assumptions(
dim, integer=True, nonnegative=True)
if ok is False:
raise ValueError(
"The dimension specification {} should be "
"a nonnegative integer.".format(dim))
def _kind(self):
return SetKind(MatrixKind(NumberKind))
PK ]ZZZNʼ
# sympy/matrices/expressions/slice.pyfrom sympy.matrices.expressions.matexpr import MatrixExpr
from sympy.core.basic import Basic
from sympy.core.containers import Tuple
from sympy.functions.elementary.integers import floor
def normalize(i, parentsize):
if isinstance(i, slice):
i = (i.start, i.stop, i.step)
if not isinstance(i, (tuple, list, Tuple)):
if (i < 0) == True:
i += parentsize
i = (i, i+1, 1)
i = list(i)
if len(i) == 2:
i.append(1)
start, stop, step = i
start = start or 0
if stop is None:
stop = parentsize
if (start < 0) == True:
start += parentsize
if (stop < 0) == True:
stop += parentsize
step = step or 1
if ((stop - start) * step < 1) == True:
raise IndexError()
return (start, stop, step)
class MatrixSlice(MatrixExpr):
""" A MatrixSlice of a Matrix Expression
Examples
========
>>> from sympy import MatrixSlice, ImmutableMatrix
>>> M = ImmutableMatrix(4, 4, range(16))
>>> M
Matrix([
[ 0, 1, 2, 3],
[ 4, 5, 6, 7],
[ 8, 9, 10, 11],
[12, 13, 14, 15]])
>>> B = MatrixSlice(M, (0, 2), (2, 4))
>>> ImmutableMatrix(B)
Matrix([
[2, 3],
[6, 7]])
"""
parent = property(lambda self: self.args[0])
rowslice = property(lambda self: self.args[1])
colslice = property(lambda self: self.args[2])
def __new__(cls, parent, rowslice, colslice):
rowslice = normalize(rowslice, parent.shape[0])
colslice = normalize(colslice, parent.shape[1])
if not (len(rowslice) == len(colslice) == 3):
raise IndexError()
if ((0 > rowslice[0]) == True or
(parent.shape[0] < rowslice[1]) == True or
(0 > colslice[0]) == True or
(parent.shape[1] < colslice[1]) == True):
raise IndexError()
if isinstance(parent, MatrixSlice):
return mat_slice_of_slice(parent, rowslice, colslice)
return Basic.__new__(cls, parent, Tuple(*rowslice), Tuple(*colslice))
@property
def shape(self):
rows = self.rowslice[1] - self.rowslice[0]
rows = rows if self.rowslice[2] == 1 else floor(rows/self.rowslice[2])
cols = self.colslice[1] - self.colslice[0]
cols = cols if self.colslice[2] == 1 else floor(cols/self.colslice[2])
return rows, cols
def _entry(self, i, j, **kwargs):
return self.parent._entry(i*self.rowslice[2] + self.rowslice[0],
j*self.colslice[2] + self.colslice[0],
**kwargs)
@property
def on_diag(self):
return self.rowslice == self.colslice
def slice_of_slice(s, t):
start1, stop1, step1 = s
start2, stop2, step2 = t
start = start1 + start2*step1
step = step1 * step2
stop = start1 + step1*stop2
if stop > stop1:
raise IndexError()
return start, stop, step
def mat_slice_of_slice(parent, rowslice, colslice):
""" Collapse nested matrix slices
>>> from sympy import MatrixSymbol
>>> X = MatrixSymbol('X', 10, 10)
>>> X[:, 1:5][5:8, :]
X[5:8, 1:5]
>>> X[1:9:2, 2:6][1:3, 2]
X[3:7:2, 4:5]
"""
row = slice_of_slice(parent.rowslice, rowslice)
col = slice_of_slice(parent.colslice, colslice)
return MatrixSlice(parent.parent, row, col)
PK ]ZZZ30�K K % sympy/matrices/expressions/special.pyfrom sympy.assumptions.ask import ask, Q
from sympy.core.relational import Eq
from sympy.core.singleton import S
from sympy.core.sympify import _sympify
from sympy.functions.special.tensor_functions import KroneckerDelta
from sympy.matrices.exceptions import NonInvertibleMatrixError
from .matexpr import MatrixExpr
class ZeroMatrix(MatrixExpr):
"""The Matrix Zero 0 - additive identity
Examples
========
>>> from sympy import MatrixSymbol, ZeroMatrix
>>> A = MatrixSymbol('A', 3, 5)
>>> Z = ZeroMatrix(3, 5)
>>> A + Z
A
>>> Z*A.T
0
"""
is_ZeroMatrix = True
def __new__(cls, m, n):
m, n = _sympify(m), _sympify(n)
cls._check_dim(m)
cls._check_dim(n)
return super().__new__(cls, m, n)
@property
def shape(self):
return (self.args[0], self.args[1])
def _eval_power(self, exp):
# exp = -1, 0, 1 are already handled at this stage
if (exp < 0) == True:
raise NonInvertibleMatrixError("Matrix det == 0; not invertible")
return self
def _eval_transpose(self):
return ZeroMatrix(self.cols, self.rows)
def _eval_adjoint(self):
return ZeroMatrix(self.cols, self.rows)
def _eval_trace(self):
return S.Zero
def _eval_determinant(self):
return S.Zero
def _eval_inverse(self):
raise NonInvertibleMatrixError("Matrix det == 0; not invertible.")
def _eval_as_real_imag(self):
return (self, self)
def _eval_conjugate(self):
return self
def _entry(self, i, j, **kwargs):
return S.Zero
class GenericZeroMatrix(ZeroMatrix):
"""
A zero matrix without a specified shape
This exists primarily so MatAdd() with no arguments can return something
meaningful.
"""
def __new__(cls):
# super(ZeroMatrix, cls) instead of super(GenericZeroMatrix, cls)
# because ZeroMatrix.__new__ doesn't have the same signature
return super(ZeroMatrix, cls).__new__(cls)
@property
def rows(self):
raise TypeError("GenericZeroMatrix does not have a specified shape")
@property
def cols(self):
raise TypeError("GenericZeroMatrix does not have a specified shape")
@property
def shape(self):
raise TypeError("GenericZeroMatrix does not have a specified shape")
# Avoid Matrix.__eq__ which might call .shape
def __eq__(self, other):
return isinstance(other, GenericZeroMatrix)
def __ne__(self, other):
return not (self == other)
def __hash__(self):
return super().__hash__()
class Identity(MatrixExpr):
"""The Matrix Identity I - multiplicative identity
Examples
========
>>> from sympy import Identity, MatrixSymbol
>>> A = MatrixSymbol('A', 3, 5)
>>> I = Identity(3)
>>> I*A
A
"""
is_Identity = True
def __new__(cls, n):
n = _sympify(n)
cls._check_dim(n)
return super().__new__(cls, n)
@property
def rows(self):
return self.args[0]
@property
def cols(self):
return self.args[0]
@property
def shape(self):
return (self.args[0], self.args[0])
@property
def is_square(self):
return True
def _eval_transpose(self):
return self
def _eval_trace(self):
return self.rows
def _eval_inverse(self):
return self
def _eval_as_real_imag(self):
return (self, ZeroMatrix(*self.shape))
def _eval_conjugate(self):
return self
def _eval_adjoint(self):
return self
def _entry(self, i, j, **kwargs):
eq = Eq(i, j)
if eq is S.true:
return S.One
elif eq is S.false:
return S.Zero
return KroneckerDelta(i, j, (0, self.cols-1))
def _eval_determinant(self):
return S.One
def _eval_power(self, exp):
return self
class GenericIdentity(Identity):
"""
An identity matrix without a specified shape
This exists primarily so MatMul() with no arguments can return something
meaningful.
"""
def __new__(cls):
# super(Identity, cls) instead of super(GenericIdentity, cls) because
# Identity.__new__ doesn't have the same signature
return super(Identity, cls).__new__(cls)
@property
def rows(self):
raise TypeError("GenericIdentity does not have a specified shape")
@property
def cols(self):
raise TypeError("GenericIdentity does not have a specified shape")
@property
def shape(self):
raise TypeError("GenericIdentity does not have a specified shape")
@property
def is_square(self):
return True
# Avoid Matrix.__eq__ which might call .shape
def __eq__(self, other):
return isinstance(other, GenericIdentity)
def __ne__(self, other):
return not (self == other)
def __hash__(self):
return super().__hash__()
class OneMatrix(MatrixExpr):
"""
Matrix whose all entries are ones.
"""
def __new__(cls, m, n, evaluate=False):
m, n = _sympify(m), _sympify(n)
cls._check_dim(m)
cls._check_dim(n)
if evaluate:
condition = Eq(m, 1) & Eq(n, 1)
if condition == True:
return Identity(1)
obj = super().__new__(cls, m, n)
return obj
@property
def shape(self):
return self._args
@property
def is_Identity(self):
return self._is_1x1() == True
def as_explicit(self):
from sympy.matrices.immutable import ImmutableDenseMatrix
return ImmutableDenseMatrix.ones(*self.shape)
def doit(self, **hints):
args = self.args
if hints.get('deep', True):
args = [a.doit(**hints) for a in args]
return self.func(*args, evaluate=True)
def _eval_power(self, exp):
# exp = -1, 0, 1 are already handled at this stage
if self._is_1x1() == True:
return Identity(1)
if (exp < 0) == True:
raise NonInvertibleMatrixError("Matrix det == 0; not invertible")
if ask(Q.integer(exp)):
return self.shape[0] ** (exp - 1) * OneMatrix(*self.shape)
return super()._eval_power(exp)
def _eval_transpose(self):
return OneMatrix(self.cols, self.rows)
def _eval_adjoint(self):
return OneMatrix(self.cols, self.rows)
def _eval_trace(self):
return S.One*self.rows
def _is_1x1(self):
"""Returns true if the matrix is known to be 1x1"""
shape = self.shape
return Eq(shape[0], 1) & Eq(shape[1], 1)
def _eval_determinant(self):
condition = self._is_1x1()
if condition == True:
return S.One
elif condition == False:
return S.Zero
else:
from sympy.matrices.expressions.determinant import Determinant
return Determinant(self)
def _eval_inverse(self):
condition = self._is_1x1()
if condition == True:
return Identity(1)
elif condition == False:
raise NonInvertibleMatrixError("Matrix det == 0; not invertible.")
else:
from .inverse import Inverse
return Inverse(self)
def _eval_as_real_imag(self):
return (self, ZeroMatrix(*self.shape))
def _eval_conjugate(self):
return self
def _entry(self, i, j, **kwargs):
return S.One
PK ]ZZZ��� � # sympy/matrices/expressions/trace.pyfrom sympy.core.basic import Basic
from sympy.core.expr import Expr, ExprBuilder
from sympy.core.singleton import S
from sympy.core.sorting import default_sort_key
from sympy.core.symbol import uniquely_named_symbol
from sympy.core.sympify import sympify
from sympy.matrices.matrixbase import MatrixBase
from sympy.matrices.exceptions import NonSquareMatrixError
class Trace(Expr):
"""Matrix Trace
Represents the trace of a matrix expression.
Examples
========
>>> from sympy import MatrixSymbol, Trace, eye
>>> A = MatrixSymbol('A', 3, 3)
>>> Trace(A)
Trace(A)
>>> Trace(eye(3))
Trace(Matrix([
[1, 0, 0],
[0, 1, 0],
[0, 0, 1]]))
>>> Trace(eye(3)).simplify()
3
"""
is_Trace = True
is_commutative = True
def __new__(cls, mat):
mat = sympify(mat)
if not mat.is_Matrix:
raise TypeError("input to Trace, %s, is not a matrix" % str(mat))
if mat.is_square is False:
raise NonSquareMatrixError("Trace of a non-square matrix")
return Basic.__new__(cls, mat)
def _eval_transpose(self):
return self
def _eval_derivative(self, v):
from sympy.concrete.summations import Sum
from .matexpr import MatrixElement
if isinstance(v, MatrixElement):
return self.rewrite(Sum).diff(v)
expr = self.doit()
if isinstance(expr, Trace):
# Avoid looping infinitely:
raise NotImplementedError
return expr._eval_derivative(v)
def _eval_derivative_matrix_lines(self, x):
from sympy.tensor.array.expressions.array_expressions import ArrayTensorProduct, ArrayContraction
r = self.args[0]._eval_derivative_matrix_lines(x)
for lr in r:
if lr.higher == 1:
lr.higher = ExprBuilder(
ArrayContraction,
[
ExprBuilder(
ArrayTensorProduct,
[
lr._lines[0],
lr._lines[1],
]
),
(1, 3),
],
validator=ArrayContraction._validate
)
else:
# This is not a matrix line:
lr.higher = ExprBuilder(
ArrayContraction,
[
ExprBuilder(
ArrayTensorProduct,
[
lr._lines[0],
lr._lines[1],
lr.higher,
]
),
(1, 3), (0, 2)
]
)
lr._lines = [S.One, S.One]
lr._first_pointer_parent = lr._lines
lr._second_pointer_parent = lr._lines
lr._first_pointer_index = 0
lr._second_pointer_index = 1
return r
@property
def arg(self):
return self.args[0]
def doit(self, **hints):
if hints.get('deep', True):
arg = self.arg.doit(**hints)
result = arg._eval_trace()
if result is not None:
return result
else:
return Trace(arg)
else:
# _eval_trace would go too deep here
if isinstance(self.arg, MatrixBase):
return trace(self.arg)
else:
return Trace(self.arg)
def as_explicit(self):
return Trace(self.arg.as_explicit()).doit()
def _normalize(self):
# Normalization of trace of matrix products. Use transposition and
# cyclic properties of traces to make sure the arguments of the matrix
# product are sorted and the first argument is not a transposition.
from sympy.matrices.expressions.matmul import MatMul
from sympy.matrices.expressions.transpose import Transpose
trace_arg = self.arg
if isinstance(trace_arg, MatMul):
def get_arg_key(x):
a = trace_arg.args[x]
if isinstance(a, Transpose):
a = a.arg
return default_sort_key(a)
indmin = min(range(len(trace_arg.args)), key=get_arg_key)
if isinstance(trace_arg.args[indmin], Transpose):
trace_arg = Transpose(trace_arg).doit()
indmin = min(range(len(trace_arg.args)), key=lambda x: default_sort_key(trace_arg.args[x]))
trace_arg = MatMul.fromiter(trace_arg.args[indmin:] + trace_arg.args[:indmin])
return Trace(trace_arg)
return self
def _eval_rewrite_as_Sum(self, expr, **kwargs):
from sympy.concrete.summations import Sum
i = uniquely_named_symbol('i', [expr])
s = Sum(self.arg[i, i], (i, 0, self.arg.rows - 1))
return s.doit()
def trace(expr):
"""Trace of a Matrix. Sum of the diagonal elements.
Examples
========
>>> from sympy import trace, Symbol, MatrixSymbol, eye
>>> n = Symbol('n')
>>> X = MatrixSymbol('X', n, n) # A square matrix
>>> trace(2*X)
2*Trace(X)
>>> trace(eye(3))
3
"""
return Trace(expr).doit()
PK ]ZZZ����U
U
' sympy/matrices/expressions/transpose.pyfrom sympy.core.basic import Basic
from sympy.matrices.expressions.matexpr import MatrixExpr
class Transpose(MatrixExpr):
"""
The transpose of a matrix expression.
This is a symbolic object that simply stores its argument without
evaluating it. To actually compute the transpose, use the ``transpose()``
function, or the ``.T`` attribute of matrices.
Examples
========
>>> from sympy import MatrixSymbol, Transpose, transpose
>>> A = MatrixSymbol('A', 3, 5)
>>> B = MatrixSymbol('B', 5, 3)
>>> Transpose(A)
A.T
>>> A.T == transpose(A) == Transpose(A)
True
>>> Transpose(A*B)
(A*B).T
>>> transpose(A*B)
B.T*A.T
"""
is_Transpose = True
def doit(self, **hints):
arg = self.arg
if hints.get('deep', True) and isinstance(arg, Basic):
arg = arg.doit(**hints)
_eval_transpose = getattr(arg, '_eval_transpose', None)
if _eval_transpose is not None:
result = _eval_transpose()
return result if result is not None else Transpose(arg)
else:
return Transpose(arg)
@property
def arg(self):
return self.args[0]
@property
def shape(self):
return self.arg.shape[::-1]
def _entry(self, i, j, expand=False, **kwargs):
return self.arg._entry(j, i, expand=expand, **kwargs)
def _eval_adjoint(self):
return self.arg.conjugate()
def _eval_conjugate(self):
return self.arg.adjoint()
def _eval_transpose(self):
return self.arg
def _eval_trace(self):
from .trace import Trace
return Trace(self.arg) # Trace(X.T) => Trace(X)
def _eval_determinant(self):
from sympy.matrices.expressions.determinant import det
return det(self.arg)
def _eval_derivative(self, x):
# x is a scalar:
return self.arg._eval_derivative(x)
def _eval_derivative_matrix_lines(self, x):
lines = self.args[0]._eval_derivative_matrix_lines(x)
return [i.transpose() for i in lines]
def transpose(expr):
"""Matrix transpose"""
return Transpose(expr).doit(deep=False)
from sympy.assumptions.ask import ask, Q
from sympy.assumptions.refine import handlers_dict
def refine_Transpose(expr, assumptions):
"""
>>> from sympy import MatrixSymbol, Q, assuming, refine
>>> X = MatrixSymbol('X', 2, 2)
>>> X.T
X.T
>>> with assuming(Q.symmetric(X)):
... print(refine(X.T))
X
"""
if ask(Q.symmetric(expr), assumptions):
return expr.arg
return expr
handlers_dict['Transpose'] = refine_Transpose
PK ]ZZZ���� " sympy/multipledispatch/__init__.pyfrom .core import dispatch
from .dispatcher import (Dispatcher, halt_ordering, restart_ordering,
MDNotImplementedError)
__version__ = '0.4.9'
__all__ = [
'dispatch',
'Dispatcher', 'halt_ordering', 'restart_ordering', 'MDNotImplementedError',
]
PK ]ZZZ�}6E E " sympy/multipledispatch/conflict.pyfrom .utils import _toposort, groupby
class AmbiguityWarning(Warning):
pass
def supercedes(a, b):
""" A is consistent and strictly more specific than B """
return len(a) == len(b) and all(map(issubclass, a, b))
def consistent(a, b):
""" It is possible for an argument list to satisfy both A and B """
return (len(a) == len(b) and
all(issubclass(aa, bb) or issubclass(bb, aa)
for aa, bb in zip(a, b)))
def ambiguous(a, b):
""" A is consistent with B but neither is strictly more specific """
return consistent(a, b) and not (supercedes(a, b) or supercedes(b, a))
def ambiguities(signatures):
""" All signature pairs such that A is ambiguous with B """
signatures = list(map(tuple, signatures))
return {(a, b) for a in signatures for b in signatures
if hash(a) < hash(b)
and ambiguous(a, b)
and not any(supercedes(c, a) and supercedes(c, b)
for c in signatures)}
def super_signature(signatures):
""" A signature that would break ambiguities """
n = len(signatures[0])
assert all(len(s) == n for s in signatures)
return [max([type.mro(sig[i]) for sig in signatures], key=len)[0]
for i in range(n)]
def edge(a, b, tie_breaker=hash):
""" A should be checked before B
Tie broken by tie_breaker, defaults to ``hash``
"""
if supercedes(a, b):
if supercedes(b, a):
return tie_breaker(a) > tie_breaker(b)
else:
return True
return False
def ordering(signatures):
""" A sane ordering of signatures to check, first to last
Topoological sort of edges as given by ``edge`` and ``supercedes``
"""
signatures = list(map(tuple, signatures))
edges = [(a, b) for a in signatures for b in signatures if edge(a, b)]
edges = groupby(lambda x: x[0], edges)
for s in signatures:
if s not in edges:
edges[s] = []
edges = {k: [b for a, b in v] for k, v in edges.items()}
return _toposort(edges)
PK ]ZZZ4���� � sympy/multipledispatch/core.pyfrom __future__ import annotations
from typing import Any
import inspect
from .dispatcher import Dispatcher, MethodDispatcher, ambiguity_warn
# XXX: This parameter to dispatch isn't documented and isn't used anywhere in
# sympy. Maybe it should just be removed.
global_namespace: dict[str, Any] = {}
def dispatch(*types, namespace=global_namespace, on_ambiguity=ambiguity_warn):
""" Dispatch function on the types of the inputs
Supports dispatch on all non-keyword arguments.
Collects implementations based on the function name. Ignores namespaces.
If ambiguous type signatures occur a warning is raised when the function is
defined suggesting the additional method to break the ambiguity.
Examples
--------
>>> from sympy.multipledispatch import dispatch
>>> @dispatch(int)
... def f(x):
... return x + 1
>>> @dispatch(float)
... def f(x): # noqa: F811
... return x - 1
>>> f(3)
4
>>> f(3.0)
2.0
Specify an isolated namespace with the namespace keyword argument
>>> my_namespace = dict()
>>> @dispatch(int, namespace=my_namespace)
... def foo(x):
... return x + 1
Dispatch on instance methods within classes
>>> class MyClass(object):
... @dispatch(list)
... def __init__(self, data):
... self.data = data
... @dispatch(int)
... def __init__(self, datum): # noqa: F811
... self.data = [datum]
"""
types = tuple(types)
def _(func):
name = func.__name__
if ismethod(func):
dispatcher = inspect.currentframe().f_back.f_locals.get(
name,
MethodDispatcher(name))
else:
if name not in namespace:
namespace[name] = Dispatcher(name)
dispatcher = namespace[name]
dispatcher.add(types, func, on_ambiguity=on_ambiguity)
return dispatcher
return _
def ismethod(func):
""" Is func a method?
Note that this has to work as the method is defined but before the class is
defined. At this stage methods look like functions.
"""
signature = inspect.signature(func)
return signature.parameters.get('self', None) is not None
PK ]ZZZ�p
�/ �/ $ sympy/multipledispatch/dispatcher.pyfrom __future__ import annotations
from warnings import warn
import inspect
from .conflict import ordering, ambiguities, super_signature, AmbiguityWarning
from .utils import expand_tuples
import itertools as itl
class MDNotImplementedError(NotImplementedError):
""" A NotImplementedError for multiple dispatch """
### Functions for on_ambiguity
def ambiguity_warn(dispatcher, ambiguities):
""" Raise warning when ambiguity is detected
Parameters
----------
dispatcher : Dispatcher
The dispatcher on which the ambiguity was detected
ambiguities : set
Set of type signature pairs that are ambiguous within this dispatcher
See Also:
Dispatcher.add
warning_text
"""
warn(warning_text(dispatcher.name, ambiguities), AmbiguityWarning)
class RaiseNotImplementedError:
"""Raise ``NotImplementedError`` when called."""
def __init__(self, dispatcher):
self.dispatcher = dispatcher
def __call__(self, *args, **kwargs):
types = tuple(type(a) for a in args)
raise NotImplementedError(
"Ambiguous signature for %s: <%s>" % (
self.dispatcher.name, str_signature(types)
))
def ambiguity_register_error_ignore_dup(dispatcher, ambiguities):
"""
If super signature for ambiguous types is duplicate types, ignore it.
Else, register instance of ``RaiseNotImplementedError`` for ambiguous types.
Parameters
----------
dispatcher : Dispatcher
The dispatcher on which the ambiguity was detected
ambiguities : set
Set of type signature pairs that are ambiguous within this dispatcher
See Also:
Dispatcher.add
ambiguity_warn
"""
for amb in ambiguities:
signature = tuple(super_signature(amb))
if len(set(signature)) == 1:
continue
dispatcher.add(
signature, RaiseNotImplementedError(dispatcher),
on_ambiguity=ambiguity_register_error_ignore_dup
)
###
_unresolved_dispatchers: set[Dispatcher] = set()
_resolve = [True]
def halt_ordering():
_resolve[0] = False
def restart_ordering(on_ambiguity=ambiguity_warn):
_resolve[0] = True
while _unresolved_dispatchers:
dispatcher = _unresolved_dispatchers.pop()
dispatcher.reorder(on_ambiguity=on_ambiguity)
class Dispatcher:
""" Dispatch methods based on type signature
Use ``dispatch`` to add implementations
Examples
--------
>>> from sympy.multipledispatch import dispatch
>>> @dispatch(int)
... def f(x):
... return x + 1
>>> @dispatch(float)
... def f(x): # noqa: F811
... return x - 1
>>> f(3)
4
>>> f(3.0)
2.0
"""
__slots__ = '__name__', 'name', 'funcs', 'ordering', '_cache', 'doc'
def __init__(self, name, doc=None):
self.name = self.__name__ = name
self.funcs = {}
self._cache = {}
self.ordering = []
self.doc = doc
def register(self, *types, **kwargs):
""" Register dispatcher with new implementation
>>> from sympy.multipledispatch.dispatcher import Dispatcher
>>> f = Dispatcher('f')
>>> @f.register(int)
... def inc(x):
... return x + 1
>>> @f.register(float)
... def dec(x):
... return x - 1
>>> @f.register(list)
... @f.register(tuple)
... def reverse(x):
... return x[::-1]
>>> f(1)
2
>>> f(1.0)
0.0
>>> f([1, 2, 3])
[3, 2, 1]
"""
def _(func):
self.add(types, func, **kwargs)
return func
return _
@classmethod
def get_func_params(cls, func):
if hasattr(inspect, "signature"):
sig = inspect.signature(func)
return sig.parameters.values()
@classmethod
def get_func_annotations(cls, func):
""" Get annotations of function positional parameters
"""
params = cls.get_func_params(func)
if params:
Parameter = inspect.Parameter
params = (param for param in params
if param.kind in
(Parameter.POSITIONAL_ONLY,
Parameter.POSITIONAL_OR_KEYWORD))
annotations = tuple(
param.annotation
for param in params)
if not any(ann is Parameter.empty for ann in annotations):
return annotations
def add(self, signature, func, on_ambiguity=ambiguity_warn):
""" Add new types/method pair to dispatcher
>>> from sympy.multipledispatch import Dispatcher
>>> D = Dispatcher('add')
>>> D.add((int, int), lambda x, y: x + y)
>>> D.add((float, float), lambda x, y: x + y)
>>> D(1, 2)
3
>>> D(1, 2.0)
Traceback (most recent call last):
...
NotImplementedError: Could not find signature for add: <int, float>
When ``add`` detects a warning it calls the ``on_ambiguity`` callback
with a dispatcher/itself, and a set of ambiguous type signature pairs
as inputs. See ``ambiguity_warn`` for an example.
"""
# Handle annotations
if not signature:
annotations = self.get_func_annotations(func)
if annotations:
signature = annotations
# Handle union types
if any(isinstance(typ, tuple) for typ in signature):
for typs in expand_tuples(signature):
self.add(typs, func, on_ambiguity)
return
for typ in signature:
if not isinstance(typ, type):
str_sig = ', '.join(c.__name__ if isinstance(c, type)
else str(c) for c in signature)
raise TypeError("Tried to dispatch on non-type: %s\n"
"In signature: <%s>\n"
"In function: %s" %
(typ, str_sig, self.name))
self.funcs[signature] = func
self.reorder(on_ambiguity=on_ambiguity)
self._cache.clear()
def reorder(self, on_ambiguity=ambiguity_warn):
if _resolve[0]:
self.ordering = ordering(self.funcs)
amb = ambiguities(self.funcs)
if amb:
on_ambiguity(self, amb)
else:
_unresolved_dispatchers.add(self)
def __call__(self, *args, **kwargs):
types = tuple([type(arg) for arg in args])
try:
func = self._cache[types]
except KeyError:
func = self.dispatch(*types)
if not func:
raise NotImplementedError(
'Could not find signature for %s: <%s>' %
(self.name, str_signature(types)))
self._cache[types] = func
try:
return func(*args, **kwargs)
except MDNotImplementedError:
funcs = self.dispatch_iter(*types)
next(funcs) # burn first
for func in funcs:
try:
return func(*args, **kwargs)
except MDNotImplementedError:
pass
raise NotImplementedError("Matching functions for "
"%s: <%s> found, but none completed successfully"
% (self.name, str_signature(types)))
def __str__(self):
return "<dispatched %s>" % self.name
__repr__ = __str__
def dispatch(self, *types):
""" Deterimine appropriate implementation for this type signature
This method is internal. Users should call this object as a function.
Implementation resolution occurs within the ``__call__`` method.
>>> from sympy.multipledispatch import dispatch
>>> @dispatch(int)
... def inc(x):
... return x + 1
>>> implementation = inc.dispatch(int)
>>> implementation(3)
4
>>> print(inc.dispatch(float))
None
See Also:
``sympy.multipledispatch.conflict`` - module to determine resolution order
"""
if types in self.funcs:
return self.funcs[types]
try:
return next(self.dispatch_iter(*types))
except StopIteration:
return None
def dispatch_iter(self, *types):
n = len(types)
for signature in self.ordering:
if len(signature) == n and all(map(issubclass, types, signature)):
result = self.funcs[signature]
yield result
def resolve(self, types):
""" Deterimine appropriate implementation for this type signature
.. deprecated:: 0.4.4
Use ``dispatch(*types)`` instead
"""
warn("resolve() is deprecated, use dispatch(*types)",
DeprecationWarning)
return self.dispatch(*types)
def __getstate__(self):
return {'name': self.name,
'funcs': self.funcs}
def __setstate__(self, d):
self.name = d['name']
self.funcs = d['funcs']
self.ordering = ordering(self.funcs)
self._cache = {}
@property
def __doc__(self):
docs = ["Multiply dispatched method: %s" % self.name]
if self.doc:
docs.append(self.doc)
other = []
for sig in self.ordering[::-1]:
func = self.funcs[sig]
if func.__doc__:
s = 'Inputs: <%s>\n' % str_signature(sig)
s += '-' * len(s) + '\n'
s += func.__doc__.strip()
docs.append(s)
else:
other.append(str_signature(sig))
if other:
docs.append('Other signatures:\n ' + '\n '.join(other))
return '\n\n'.join(docs)
def _help(self, *args):
return self.dispatch(*map(type, args)).__doc__
def help(self, *args, **kwargs):
""" Print docstring for the function corresponding to inputs """
print(self._help(*args))
def _source(self, *args):
func = self.dispatch(*map(type, args))
if not func:
raise TypeError("No function found")
return source(func)
def source(self, *args, **kwargs):
""" Print source code for the function corresponding to inputs """
print(self._source(*args))
def source(func):
s = 'File: %s\n\n' % inspect.getsourcefile(func)
s = s + inspect.getsource(func)
return s
class MethodDispatcher(Dispatcher):
""" Dispatch methods based on type signature
See Also:
Dispatcher
"""
@classmethod
def get_func_params(cls, func):
if hasattr(inspect, "signature"):
sig = inspect.signature(func)
return itl.islice(sig.parameters.values(), 1, None)
def __get__(self, instance, owner):
self.obj = instance
self.cls = owner
return self
def __call__(self, *args, **kwargs):
types = tuple([type(arg) for arg in args])
func = self.dispatch(*types)
if not func:
raise NotImplementedError('Could not find signature for %s: <%s>' %
(self.name, str_signature(types)))
return func(self.obj, *args, **kwargs)
def str_signature(sig):
""" String representation of type signature
>>> from sympy.multipledispatch.dispatcher import str_signature
>>> str_signature((int, float))
'int, float'
"""
return ', '.join(cls.__name__ for cls in sig)
def warning_text(name, amb):
""" The text for ambiguity warnings """
text = "\nAmbiguities exist in dispatched function %s\n\n" % (name)
text += "The following signatures may result in ambiguous behavior:\n"
for pair in amb:
text += "\t" + \
', '.join('[' + str_signature(s) + ']' for s in pair) + "\n"
text += "\n\nConsider making the following additions:\n\n"
text += '\n\n'.join(['@dispatch(' + str_signature(super_signature(s))
+ ')\ndef %s(...)' % name for s in amb])
return text
PK ]ZZZ��� sympy/multipledispatch/utils.pyfrom collections import OrderedDict
def expand_tuples(L):
"""
>>> from sympy.multipledispatch.utils import expand_tuples
>>> expand_tuples([1, (2, 3)])
[(1, 2), (1, 3)]
>>> expand_tuples([1, 2])
[(1, 2)]
"""
if not L:
return [()]
elif not isinstance(L[0], tuple):
rest = expand_tuples(L[1:])
return [(L[0],) + t for t in rest]
else:
rest = expand_tuples(L[1:])
return [(item,) + t for t in rest for item in L[0]]
# Taken from theano/theano/gof/sched.py
# Avoids licensing issues because this was written by Matthew Rocklin
def _toposort(edges):
""" Topological sort algorithm by Kahn [1] - O(nodes + vertices)
inputs:
edges - a dict of the form {a: {b, c}} where b and c depend on a
outputs:
L - an ordered list of nodes that satisfy the dependencies of edges
>>> from sympy.multipledispatch.utils import _toposort
>>> _toposort({1: (2, 3), 2: (3, )})
[1, 2, 3]
Closely follows the wikipedia page [2]
[1] Kahn, Arthur B. (1962), "Topological sorting of large networks",
Communications of the ACM
[2] https://en.wikipedia.org/wiki/Toposort#Algorithms
"""
incoming_edges = reverse_dict(edges)
incoming_edges = {k: set(val) for k, val in incoming_edges.items()}
S = OrderedDict.fromkeys(v for v in edges if v not in incoming_edges)
L = []
while S:
n, _ = S.popitem()
L.append(n)
for m in edges.get(n, ()):
assert n in incoming_edges[m]
incoming_edges[m].remove(n)
if not incoming_edges[m]:
S[m] = None
if any(incoming_edges.get(v, None) for v in edges):
raise ValueError("Input has cycles")
return L
def reverse_dict(d):
"""Reverses direction of dependence dict
>>> d = {'a': (1, 2), 'b': (2, 3), 'c':()}
>>> reverse_dict(d) # doctest: +SKIP
{1: ('a',), 2: ('a', 'b'), 3: ('b',)}
:note: dict order are not deterministic. As we iterate on the
input dict, it make the output of this function depend on the
dict order. So this function output order should be considered
as undeterministic.
"""
result = {}
for key in d:
for val in d[key]:
result[val] = result.get(val, ()) + (key, )
return result
# Taken from toolz
# Avoids licensing issues because this version was authored by Matthew Rocklin
def groupby(func, seq):
""" Group a collection by a key function
>>> from sympy.multipledispatch.utils import groupby
>>> names = ['Alice', 'Bob', 'Charlie', 'Dan', 'Edith', 'Frank']
>>> groupby(len, names) # doctest: +SKIP
{3: ['Bob', 'Dan'], 5: ['Alice', 'Edith', 'Frank'], 7: ['Charlie']}
>>> iseven = lambda x: x % 2 == 0
>>> groupby(iseven, [1, 2, 3, 4, 5, 6, 7, 8]) # doctest: +SKIP
{False: [1, 3, 5, 7], True: [2, 4, 6, 8]}
See Also:
``countby``
"""
d = {}
for item in seq:
key = func(item)
if key not in d:
d[key] = []
d[key].append(item)
return d
PK ]ZZZx�*��
�
sympy/ntheory/__init__.py"""
Number theory module (primes, etc)
"""
from .generate import nextprime, prevprime, prime, primepi, primerange, \
randprime, Sieve, sieve, primorial, cycle_length, composite, compositepi
from .primetest import isprime, is_gaussian_prime, is_mersenne_prime
from .factor_ import divisors, proper_divisors, factorint, multiplicity, \
multiplicity_in_factorial, perfect_power, pollard_pm1, pollard_rho, \
primefactors, totient, \
divisor_count, proper_divisor_count, divisor_sigma, factorrat, \
reduced_totient, primenu, primeomega, mersenne_prime_exponent, \
is_perfect, is_abundant, is_deficient, is_amicable, is_carmichael, \
abundance, dra, drm
from .partitions_ import npartitions
from .residue_ntheory import is_primitive_root, is_quad_residue, \
legendre_symbol, jacobi_symbol, n_order, sqrt_mod, quadratic_residues, \
primitive_root, nthroot_mod, is_nthpow_residue, sqrt_mod_iter, mobius, \
discrete_log, quadratic_congruence, polynomial_congruence
from .multinomial import binomial_coefficients, binomial_coefficients_list, \
multinomial_coefficients
from .continued_fraction import continued_fraction_periodic, \
continued_fraction_iterator, continued_fraction_reduce, \
continued_fraction_convergents, continued_fraction
from .digits import count_digits, digits, is_palindromic
from .egyptian_fraction import egyptian_fraction
from .ecm import ecm
from .qs import qs
__all__ = [
'nextprime', 'prevprime', 'prime', 'primepi', 'primerange', 'randprime',
'Sieve', 'sieve', 'primorial', 'cycle_length', 'composite', 'compositepi',
'isprime', 'is_gaussian_prime', 'is_mersenne_prime',
'divisors', 'proper_divisors', 'factorint', 'multiplicity', 'perfect_power',
'pollard_pm1', 'pollard_rho', 'primefactors', 'totient',
'divisor_count', 'proper_divisor_count', 'divisor_sigma', 'factorrat',
'reduced_totient', 'primenu', 'primeomega', 'mersenne_prime_exponent',
'is_perfect', 'is_abundant', 'is_deficient', 'is_amicable',
'is_carmichael', 'abundance', 'dra', 'drm', 'multiplicity_in_factorial',
'npartitions',
'is_primitive_root', 'is_quad_residue', 'legendre_symbol',
'jacobi_symbol', 'n_order', 'sqrt_mod', 'quadratic_residues',
'primitive_root', 'nthroot_mod', 'is_nthpow_residue', 'sqrt_mod_iter',
'mobius', 'discrete_log', 'quadratic_congruence', 'polynomial_congruence',
'binomial_coefficients', 'binomial_coefficients_list',
'multinomial_coefficients',
'continued_fraction_periodic', 'continued_fraction_iterator',
'continued_fraction_reduce', 'continued_fraction_convergents',
'continued_fraction',
'digits',
'count_digits',
'is_palindromic',
'egyptian_fraction',
'ecm',
'qs',
]
PK ]ZZZ�4n n sympy/ntheory/bbp_pi.py'''
This implementation is a heavily modified fixed point implementation of
BBP_formula for calculating the nth position of pi. The original hosted
at: https://web.archive.org/web/20151116045029/http://en.literateprograms.org/Pi_with_the_BBP_formula_(Python)
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sub-license, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
# IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
# CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
# TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Modifications:
1.Once the nth digit and desired number of digits is selected, the
number of digits of working precision is calculated to ensure that
the hexadecimal digits returned are accurate. This is calculated as
int(math.log(start + prec)/math.log(16) + prec + 3)
--------------------------------------- --------
/ /
number of hex digits additional digits
This was checked by the following code which completed without
errors (and dig are the digits included in the test_bbp.py file):
for i in range(0,1000):
for j in range(1,1000):
a, b = pi_hex_digits(i, j), dig[i:i+j]
if a != b:
print('%s\n%s'%(a,b))
Deceasing the additional digits by 1 generated errors, so '3' is
the smallest additional precision needed to calculate the above
loop without errors. The following trailing 10 digits were also
checked to be accurate (and the times were slightly faster with
some of the constant modifications that were made):
>> from time import time
>> t=time();pi_hex_digits(10**2-10 + 1, 10), time()-t
('e90c6cc0ac', 0.0)
>> t=time();pi_hex_digits(10**4-10 + 1, 10), time()-t
('26aab49ec6', 0.17100000381469727)
>> t=time();pi_hex_digits(10**5-10 + 1, 10), time()-t
('a22673c1a5', 4.7109999656677246)
>> t=time();pi_hex_digits(10**6-10 + 1, 10), time()-t
('9ffd342362', 59.985999822616577)
>> t=time();pi_hex_digits(10**7-10 + 1, 10), time()-t
('c1a42e06a1', 689.51800012588501)
2. The while loop to evaluate whether the series has converged quits
when the addition amount `dt` has dropped to zero.
3. the formatting string to convert the decimal to hexadecimal is
calculated for the given precision.
4. pi_hex_digits(n) changed to have coefficient to the formula in an
array (perhaps just a matter of preference).
'''
from sympy.utilities.misc import as_int
def _series(j, n, prec=14):
# Left sum from the bbp algorithm
s = 0
D = _dn(n, prec)
D4 = 4 * D
d = j
for k in range(n + 1):
s += (pow(16, n - k, d) << D4) // d
d += 8
# Right sum iterates to infinity for full precision, but we
# stop at the point where one iteration is beyond the precision
# specified.
t = 0
k = n + 1
e = D4 - 4 # 4*(D + n - k)
d = 8 * k + j
while True:
dt = (1 << e) // d
if not dt:
break
t += dt
# k += 1
e -= 4
d += 8
total = s + t
return total
def pi_hex_digits(n, prec=14):
"""Returns a string containing ``prec`` (default 14) digits
starting at the nth digit of pi in hex. Counting of digits
starts at 0 and the decimal is not counted, so for n = 0 the
returned value starts with 3; n = 1 corresponds to the first
digit past the decimal point (which in hex is 2).
Parameters
==========
n : non-negative integer
prec : non-negative integer. default = 14
Returns
=======
str : Returns a string containing ``prec`` digits
starting at the nth digit of pi in hex.
If ``prec`` = 0, returns empty string.
Raises
======
ValueError
If ``n`` < 0 or ``prec`` < 0.
Or ``n`` or ``prec`` is not an integer.
Examples
========
>>> from sympy.ntheory.bbp_pi import pi_hex_digits
>>> pi_hex_digits(0)
'3243f6a8885a30'
>>> pi_hex_digits(0, 3)
'324'
These are consistent with the following results
>>> import math
>>> hex(int(math.pi * 2**((14-1)*4)))
'0x3243f6a8885a30'
>>> hex(int(math.pi * 2**((3-1)*4)))
'0x324'
References
==========
.. [1] http://www.numberworld.org/digits/Pi/
"""
n, prec = as_int(n), as_int(prec)
if n < 0:
raise ValueError('n cannot be negative')
if prec < 0:
raise ValueError('prec cannot be negative')
if prec == 0:
return ''
# main of implementation arrays holding formulae coefficients
n -= 1
a = [4, 2, 1, 1]
j = [1, 4, 5, 6]
#formulae
D = _dn(n, prec)
x = + (a[0]*_series(j[0], n, prec)
- a[1]*_series(j[1], n, prec)
- a[2]*_series(j[2], n, prec)
- a[3]*_series(j[3], n, prec)) & (16**D - 1)
s = ("%0" + "%ix" % prec) % (x // 16**(D - prec))
return s
def _dn(n, prec):
# controller for n dependence on precision
# n = starting digit index
# prec = the number of total digits to compute
n += 1 # because we subtract 1 for _series
# assert int(math.log(n + prec)/math.log(16)) ==\
# ((n + prec).bit_length() - 1) // 4
return ((n + prec).bit_length() - 1) // 4 + prec + 3
PK ]ZZZU����) �) # sympy/ntheory/continued_fraction.pyfrom __future__ import annotations
import itertools
from sympy.core.exprtools import factor_terms
from sympy.core.numbers import Integer, Rational
from sympy.core.singleton import S
from sympy.core.symbol import Dummy
from sympy.core.sympify import _sympify
from sympy.utilities.misc import as_int
def continued_fraction(a) -> list:
"""Return the continued fraction representation of a Rational or
quadratic irrational.
Examples
========
>>> from sympy.ntheory.continued_fraction import continued_fraction
>>> from sympy import sqrt
>>> continued_fraction((1 + 2*sqrt(3))/5)
[0, 1, [8, 3, 34, 3]]
See Also
========
continued_fraction_periodic, continued_fraction_reduce, continued_fraction_convergents
"""
e = _sympify(a)
if all(i.is_Rational for i in e.atoms()):
if e.is_Integer:
return continued_fraction_periodic(e, 1, 0)
elif e.is_Rational:
return continued_fraction_periodic(e.p, e.q, 0)
elif e.is_Pow and e.exp is S.Half and e.base.is_Integer:
return continued_fraction_periodic(0, 1, e.base)
elif e.is_Mul and len(e.args) == 2 and (
e.args[0].is_Rational and
e.args[1].is_Pow and
e.args[1].base.is_Integer and
e.args[1].exp is S.Half):
a, b = e.args
return continued_fraction_periodic(0, a.q, b.base, a.p)
else:
# this should not have to work very hard- no
# simplification, cancel, etc... which should be
# done by the user. e.g. This is a fancy 1 but
# the user should simplify it first:
# sqrt(2)*(1 + sqrt(2))/(sqrt(2) + 2)
p, d = e.expand().as_numer_denom()
if d.is_Integer:
if p.is_Rational:
return continued_fraction_periodic(p, d)
# look for a + b*c
# with c = sqrt(s)
if p.is_Add and len(p.args) == 2:
a, bc = p.args
else:
a = S.Zero
bc = p
if a.is_Integer:
b = S.NaN
if bc.is_Mul and len(bc.args) == 2:
b, c = bc.args
elif bc.is_Pow:
b = Integer(1)
c = bc
if b.is_Integer and (
c.is_Pow and c.exp is S.Half and
c.base.is_Integer):
# (a + b*sqrt(c))/d
c = c.base
return continued_fraction_periodic(a, d, c, b)
raise ValueError(
'expecting a rational or quadratic irrational, not %s' % e)
def continued_fraction_periodic(p, q, d=0, s=1) -> list:
r"""
Find the periodic continued fraction expansion of a quadratic irrational.
Compute the continued fraction expansion of a rational or a
quadratic irrational number, i.e. `\frac{p + s\sqrt{d}}{q}`, where
`p`, `q \ne 0` and `d \ge 0` are integers.
Returns the continued fraction representation (canonical form) as
a list of integers, optionally ending (for quadratic irrationals)
with list of integers representing the repeating digits.
Parameters
==========
p : int
the rational part of the number's numerator
q : int
the denominator of the number
d : int, optional
the irrational part (discriminator) of the number's numerator
s : int, optional
the coefficient of the irrational part
Examples
========
>>> from sympy.ntheory.continued_fraction import continued_fraction_periodic
>>> continued_fraction_periodic(3, 2, 7)
[2, [1, 4, 1, 1]]
Golden ratio has the simplest continued fraction expansion:
>>> continued_fraction_periodic(1, 2, 5)
[[1]]
If the discriminator is zero or a perfect square then the number will be a
rational number:
>>> continued_fraction_periodic(4, 3, 0)
[1, 3]
>>> continued_fraction_periodic(4, 3, 49)
[3, 1, 2]
See Also
========
continued_fraction_iterator, continued_fraction_reduce
References
==========
.. [1] https://en.wikipedia.org/wiki/Periodic_continued_fraction
.. [2] K. Rosen. Elementary Number theory and its applications.
Addison-Wesley, 3 Sub edition, pages 379-381, January 1992.
"""
from sympy.functions import sqrt, floor
p, q, d, s = list(map(as_int, [p, q, d, s]))
if d < 0:
raise ValueError("expected non-negative for `d` but got %s" % d)
if q == 0:
raise ValueError("The denominator cannot be 0.")
if not s:
d = 0
# check for rational case
sd = sqrt(d)
if sd.is_Integer:
return list(continued_fraction_iterator(Rational(p + s*sd, q)))
# irrational case with sd != Integer
if q < 0:
p, q, s = -p, -q, -s
n = (p + s*sd)/q
if n < 0:
w = floor(-n)
f = -n - w
one_f = continued_fraction(1 - f) # 1-f < 1 so cf is [0 ... [...]]
one_f[0] -= w + 1
return one_f
d *= s**2
sd *= s
if (d - p**2)%q:
d *= q**2
sd *= q
p *= q
q *= q
terms: list[int] = []
pq = {}
while (p, q) not in pq:
pq[(p, q)] = len(terms)
terms.append((p + sd)//q)
p = terms[-1]*q - p
q = (d - p**2)//q
i = pq[(p, q)]
return terms[:i] + [terms[i:]] # type: ignore
def continued_fraction_reduce(cf):
"""
Reduce a continued fraction to a rational or quadratic irrational.
Compute the rational or quadratic irrational number from its
terminating or periodic continued fraction expansion. The
continued fraction expansion (cf) should be supplied as a
terminating iterator supplying the terms of the expansion. For
terminating continued fractions, this is equivalent to
``list(continued_fraction_convergents(cf))[-1]``, only a little more
efficient. If the expansion has a repeating part, a list of the
repeating terms should be returned as the last element from the
iterator. This is the format returned by
continued_fraction_periodic.
For quadratic irrationals, returns the largest solution found,
which is generally the one sought, if the fraction is in canonical
form (all terms positive except possibly the first).
Examples
========
>>> from sympy.ntheory.continued_fraction import continued_fraction_reduce
>>> continued_fraction_reduce([1, 2, 3, 4, 5])
225/157
>>> continued_fraction_reduce([-2, 1, 9, 7, 1, 2])
-256/233
>>> continued_fraction_reduce([2, 1, 2, 1, 1, 4, 1, 1, 6, 1, 1, 8]).n(10)
2.718281835
>>> continued_fraction_reduce([1, 4, 2, [3, 1]])
(sqrt(21) + 287)/238
>>> continued_fraction_reduce([[1]])
(1 + sqrt(5))/2
>>> from sympy.ntheory.continued_fraction import continued_fraction_periodic
>>> continued_fraction_reduce(continued_fraction_periodic(8, 5, 13))
(sqrt(13) + 8)/5
See Also
========
continued_fraction_periodic
"""
from sympy.solvers import solve
period = []
x = Dummy('x')
def untillist(cf):
for nxt in cf:
if isinstance(nxt, list):
period.extend(nxt)
yield x
break
yield nxt
a = S.Zero
for a in continued_fraction_convergents(untillist(cf)):
pass
if period:
y = Dummy('y')
solns = solve(continued_fraction_reduce(period + [y]) - y, y)
solns.sort()
pure = solns[-1]
rv = a.subs(x, pure).radsimp()
else:
rv = a
if rv.is_Add:
rv = factor_terms(rv)
if rv.is_Mul and rv.args[0] == -1:
rv = rv.func(*rv.args)
return rv
def continued_fraction_iterator(x):
"""
Return continued fraction expansion of x as iterator.
Examples
========
>>> from sympy import Rational, pi
>>> from sympy.ntheory.continued_fraction import continued_fraction_iterator
>>> list(continued_fraction_iterator(Rational(3, 8)))
[0, 2, 1, 2]
>>> list(continued_fraction_iterator(Rational(-3, 8)))
[-1, 1, 1, 1, 2]
>>> for i, v in enumerate(continued_fraction_iterator(pi)):
... if i > 7:
... break
... print(v)
3
7
15
1
292
1
1
1
References
==========
.. [1] https://en.wikipedia.org/wiki/Continued_fraction
"""
from sympy.functions import floor
while True:
i = floor(x)
yield i
x -= i
if not x:
break
x = 1/x
def continued_fraction_convergents(cf):
"""
Return an iterator over the convergents of a continued fraction (cf).
The parameter should be in either of the following to forms:
- A list of partial quotients, possibly with the last element being a list
of repeating partial quotients, such as might be returned by
continued_fraction and continued_fraction_periodic.
- An iterable returning successive partial quotients of the continued
fraction, such as might be returned by continued_fraction_iterator.
In computing the convergents, the continued fraction need not be strictly
in canonical form (all integers, all but the first positive).
Rational and negative elements may be present in the expansion.
Examples
========
>>> from sympy.core import pi
>>> from sympy import S
>>> from sympy.ntheory.continued_fraction import \
continued_fraction_convergents, continued_fraction_iterator
>>> list(continued_fraction_convergents([0, 2, 1, 2]))
[0, 1/2, 1/3, 3/8]
>>> list(continued_fraction_convergents([1, S('1/2'), -7, S('1/4')]))
[1, 3, 19/5, 7]
>>> it = continued_fraction_convergents(continued_fraction_iterator(pi))
>>> for n in range(7):
... print(next(it))
3
22/7
333/106
355/113
103993/33102
104348/33215
208341/66317
>>> it = continued_fraction_convergents([1, [1, 2]]) # sqrt(3)
>>> for n in range(7):
... print(next(it))
1
2
5/3
7/4
19/11
26/15
71/41
See Also
========
continued_fraction_iterator, continued_fraction, continued_fraction_periodic
"""
if isinstance(cf, list) and isinstance(cf[-1], list):
cf = itertools.chain(cf[:-1], itertools.cycle(cf[-1]))
p_2, q_2 = S.Zero, S.One
p_1, q_1 = S.One, S.Zero
for a in cf:
p, q = a*p_1 + p_2, a*q_1 + q_2
p_2, q_2 = p_1, q_1
p_1, q_1 = p, q
yield p/q
PK ]ZZZG��^� � sympy/ntheory/digits.pyfrom collections import defaultdict
from sympy.utilities.iterables import multiset, is_palindromic as _palindromic
from sympy.utilities.misc import as_int
def digits(n, b=10, digits=None):
"""
Return a list of the digits of ``n`` in base ``b``. The first
element in the list is ``b`` (or ``-b`` if ``n`` is negative).
Examples
========
>>> from sympy.ntheory.digits import digits
>>> digits(35)
[10, 3, 5]
If the number is negative, the negative sign will be placed on the
base (which is the first element in the returned list):
>>> digits(-35)
[-10, 3, 5]
Bases other than 10 (and greater than 1) can be selected with ``b``:
>>> digits(27, b=2)
[2, 1, 1, 0, 1, 1]
Use the ``digits`` keyword if a certain number of digits is desired:
>>> digits(35, digits=4)
[10, 0, 0, 3, 5]
Parameters
==========
n: integer
The number whose digits are returned.
b: integer
The base in which digits are computed.
digits: integer (or None for all digits)
The number of digits to be returned (padded with zeros, if
necessary).
See Also
========
sympy.core.intfunc.num_digits, count_digits
"""
b = as_int(b)
n = as_int(n)
if b < 2:
raise ValueError("b must be greater than 1")
else:
x, y = abs(n), []
while x >= b:
x, r = divmod(x, b)
y.append(r)
y.append(x)
y.append(-b if n < 0 else b)
y.reverse()
ndig = len(y) - 1
if digits is not None:
if ndig > digits:
raise ValueError(
"For %s, at least %s digits are needed." % (n, ndig))
elif ndig < digits:
y[1:1] = [0]*(digits - ndig)
return y
def count_digits(n, b=10):
"""
Return a dictionary whose keys are the digits of ``n`` in the
given base, ``b``, with keys indicating the digits appearing in the
number and values indicating how many times that digit appeared.
Examples
========
>>> from sympy.ntheory import count_digits
>>> count_digits(1111339)
{1: 4, 3: 2, 9: 1}
The digits returned are always represented in base-10
but the number itself can be entered in any format that is
understood by Python; the base of the number can also be
given if it is different than 10:
>>> n = 0xFA; n
250
>>> count_digits(_)
{0: 1, 2: 1, 5: 1}
>>> count_digits(n, 16)
{10: 1, 15: 1}
The default dictionary will return a 0 for any digit that did
not appear in the number. For example, which digits appear 7
times in ``77!``:
>>> from sympy import factorial
>>> c77 = count_digits(factorial(77))
>>> [i for i in range(10) if c77[i] == 7]
[1, 3, 7, 9]
See Also
========
sympy.core.intfunc.num_digits, digits
"""
rv = defaultdict(int, multiset(digits(n, b)).items())
rv.pop(b) if b in rv else rv.pop(-b) # b or -b is there
return rv
def is_palindromic(n, b=10):
"""return True if ``n`` is the same when read from left to right
or right to left in the given base, ``b``.
Examples
========
>>> from sympy.ntheory import is_palindromic
>>> all(is_palindromic(i) for i in (-11, 1, 22, 121))
True
The second argument allows you to test numbers in other
bases. For example, 88 is palindromic in base-10 but not
in base-8:
>>> is_palindromic(88, 8)
False
On the other hand, a number can be palindromic in base-8 but
not in base-10:
>>> 0o121, is_palindromic(0o121)
(81, False)
Or it might be palindromic in both bases:
>>> oct(121), is_palindromic(121, 8) and is_palindromic(121)
('0o171', True)
"""
return _palindromic(digits(n, b), 1)
PK ]ZZZ��Y��- �- sympy/ntheory/ecm.pyfrom math import log
from sympy.core.random import _randint
from sympy.external.gmpy import gcd, invert, sqrt
from sympy.utilities.misc import as_int
from .generate import sieve, primerange
from .primetest import isprime
#----------------------------------------------------------------------------#
# #
# Lenstra's Elliptic Curve Factorization #
# #
#----------------------------------------------------------------------------#
class Point:
"""Montgomery form of Points in an elliptic curve.
In this form, the addition and doubling of points
does not need any y-coordinate information thus
decreasing the number of operations.
Using Montgomery form we try to perform point addition
and doubling in least amount of multiplications.
The elliptic curve used here is of the form
(E : b*y**2*z = x**3 + a*x**2*z + x*z**2).
The a_24 parameter is equal to (a + 2)/4.
References
==========
.. [1] Kris Gaj, Soonhak Kwon, Patrick Baier, Paul Kohlbrenner, Hoang Le, Mohammed Khaleeluddin, Ramakrishna Bachimanchi,
Implementing the Elliptic Curve Method of Factoring in Reconfigurable Hardware,
Cryptographic Hardware and Embedded Systems - CHES 2006 (2006), pp. 119-133,
https://doi.org/10.1007/11894063_10
https://www.hyperelliptic.org/tanja/SHARCS/talks06/Gaj.pdf
"""
def __init__(self, x_cord, z_cord, a_24, mod):
"""
Initial parameters for the Point class.
Parameters
==========
x_cord : X coordinate of the Point
z_cord : Z coordinate of the Point
a_24 : Parameter of the elliptic curve in Montgomery form
mod : modulus
"""
self.x_cord = x_cord
self.z_cord = z_cord
self.a_24 = a_24
self.mod = mod
def __eq__(self, other):
"""Two points are equal if X/Z of both points are equal
"""
if self.a_24 != other.a_24 or self.mod != other.mod:
return False
return self.x_cord * other.z_cord % self.mod ==\
other.x_cord * self.z_cord % self.mod
def add(self, Q, diff):
"""
Add two points self and Q where diff = self - Q. Moreover the assumption
is self.x_cord*Q.x_cord*(self.x_cord - Q.x_cord) != 0. This algorithm
requires 6 multiplications. Here the difference between the points
is already known and using this algorithm speeds up the addition
by reducing the number of multiplication required. Also in the
mont_ladder algorithm is constructed in a way so that the difference
between intermediate points is always equal to the initial point.
So, we always know what the difference between the point is.
Parameters
==========
Q : point on the curve in Montgomery form
diff : self - Q
Examples
========
>>> from sympy.ntheory.ecm import Point
>>> p1 = Point(11, 16, 7, 29)
>>> p2 = Point(13, 10, 7, 29)
>>> p3 = p2.add(p1, p1)
>>> p3.x_cord
23
>>> p3.z_cord
17
"""
u = (self.x_cord - self.z_cord)*(Q.x_cord + Q.z_cord)
v = (self.x_cord + self.z_cord)*(Q.x_cord - Q.z_cord)
add, subt = u + v, u - v
x_cord = diff.z_cord * add * add % self.mod
z_cord = diff.x_cord * subt * subt % self.mod
return Point(x_cord, z_cord, self.a_24, self.mod)
def double(self):
"""
Doubles a point in an elliptic curve in Montgomery form.
This algorithm requires 5 multiplications.
Examples
========
>>> from sympy.ntheory.ecm import Point
>>> p1 = Point(11, 16, 7, 29)
>>> p2 = p1.double()
>>> p2.x_cord
13
>>> p2.z_cord
10
"""
u = pow(self.x_cord + self.z_cord, 2, self.mod)
v = pow(self.x_cord - self.z_cord, 2, self.mod)
diff = u - v
x_cord = u*v % self.mod
z_cord = diff*(v + self.a_24*diff) % self.mod
return Point(x_cord, z_cord, self.a_24, self.mod)
def mont_ladder(self, k):
"""
Scalar multiplication of a point in Montgomery form
using Montgomery Ladder Algorithm.
A total of 11 multiplications are required in each step of this
algorithm.
Parameters
==========
k : The positive integer multiplier
Examples
========
>>> from sympy.ntheory.ecm import Point
>>> p1 = Point(11, 16, 7, 29)
>>> p3 = p1.mont_ladder(3)
>>> p3.x_cord
23
>>> p3.z_cord
17
"""
Q = self
R = self.double()
for i in bin(k)[3:]:
if i == '1':
Q = R.add(Q, self)
R = R.double()
else:
R = Q.add(R, self)
Q = Q.double()
return Q
def _ecm_one_factor(n, B1=10000, B2=100000, max_curve=200, seed=None):
"""Returns one factor of n using
Lenstra's 2 Stage Elliptic curve Factorization
with Suyama's Parameterization. Here Montgomery
arithmetic is used for fast computation of addition
and doubling of points in elliptic curve.
Explanation
===========
This ECM method considers elliptic curves in Montgomery
form (E : b*y**2*z = x**3 + a*x**2*z + x*z**2) and involves
elliptic curve operations (mod N), where the elements in
Z are reduced (mod N). Since N is not a prime, E over FF(N)
is not really an elliptic curve but we can still do point additions
and doubling as if FF(N) was a field.
Stage 1 : The basic algorithm involves taking a random point (P) on an
elliptic curve in FF(N). The compute k*P using Montgomery ladder algorithm.
Let q be an unknown factor of N. Then the order of the curve E, |E(FF(q))|,
might be a smooth number that divides k. Then we have k = l * |E(FF(q))|
for some l. For any point belonging to the curve E, |E(FF(q))|*P = O,
hence k*P = l*|E(FF(q))|*P. Thus kP.z_cord = 0 (mod q), and the unknownn
factor of N (q) can be recovered by taking gcd(kP.z_cord, N).
Stage 2 : This is a continuation of Stage 1 if k*P != O. The idea utilize
the fact that even if kP != 0, the value of k might miss just one large
prime divisor of |E(FF(q))|. In this case we only need to compute the
scalar multiplication by p to get p*k*P = O. Here a second bound B2
restrict the size of possible values of p.
Parameters
==========
n : Number to be Factored
B1 : Stage 1 Bound. Must be an even number.
B2 : Stage 2 Bound. Must be an even number.
max_curve : Maximum number of curves generated
Returns
=======
integer | None : ``n`` (if it is prime) else a non-trivial divisor of ``n``. ``None`` if not found
References
==========
.. [1] Carl Pomerance, Richard Crandall, Prime Numbers: A Computational Perspective,
2nd Edition (2005), page 344, ISBN:978-0387252827
"""
randint = _randint(seed)
if isprime(n):
return n
# When calculating T, if (B1 - 2*D) is negative, it cannot be calculated.
D = min(sqrt(B2), B1 // 2 - 1)
sieve.extend(D)
beta = [0] * D
S = [0] * D
k = 1
for p in primerange(2, B1 + 1):
k *= pow(p, int(log(B1, p)))
# Pre-calculate the prime numbers to be used in stage 2.
# Using the fact that the x-coordinates of point P and its
# inverse -P coincide, the number of primes to be checked
# in stage 2 can be reduced.
deltas_list = []
for r in range(B1 + 2*D, B2 + 2*D, 4*D):
deltas = set()
deltas.update((abs(q - r) - 1) // 2 for q in primerange(r - 2*D, r + 2*D))
# d in deltas iff r+(2d+1) and/or r-(2d+1) is prime
deltas_list.append(list(deltas))
for _ in range(max_curve):
#Suyama's Parametrization
sigma = randint(6, n - 1)
u = (sigma**2 - 5) % n
v = (4*sigma) % n
u_3 = pow(u, 3, n)
try:
# We use the elliptic curve y**2 = x**3 + a*x**2 + x
# where a = pow(v - u, 3, n)*(3*u + v)*invert(4*u_3*v, n) - 2
# However, we do not declare a because it is more convenient
# to use a24 = (a + 2)*invert(4, n) in the calculation.
a24 = pow(v - u, 3, n)*(3*u + v)*invert(16*u_3*v, n) % n
except ZeroDivisionError:
#If the invert(16*u_3*v, n) doesn't exist (i.e., g != 1)
g = gcd(2*u_3*v, n)
#If g = n, try another curve
if g == n:
continue
return g
Q = Point(u_3, pow(v, 3, n), a24, n)
Q = Q.mont_ladder(k)
g = gcd(Q.z_cord, n)
#Stage 1 factor
if g != 1 and g != n:
return g
#Stage 1 failure. Q.z = 0, Try another curve
elif g == n:
continue
#Stage 2 - Improved Standard Continuation
S[0] = Q
Q2 = Q.double()
S[1] = Q2.add(Q, Q)
beta[0] = (S[0].x_cord*S[0].z_cord) % n
beta[1] = (S[1].x_cord*S[1].z_cord) % n
for d in range(2, D):
S[d] = S[d - 1].add(Q2, S[d - 2])
beta[d] = (S[d].x_cord*S[d].z_cord) % n
# i.e., S[i] = Q.mont_ladder(2*i + 1)
g = 1
W = Q.mont_ladder(4*D)
T = Q.mont_ladder(B1 - 2*D)
R = Q.mont_ladder(B1 + 2*D)
for deltas in deltas_list:
# R = Q.mont_ladder(r) where r in range(B1 + 2*D, B2 + 2*D, 4*D)
alpha = (R.x_cord*R.z_cord) % n
for delta in deltas:
# We want to calculate
# f = R.x_cord * S[delta].z_cord - S[delta].x_cord * R.z_cord
f = (R.x_cord - S[delta].x_cord)*\
(R.z_cord + S[delta].z_cord) - alpha + beta[delta]
g = (g*f) % n
T, R = R, R.add(W, T)
g = gcd(n, g)
#Stage 2 Factor found
if g != 1 and g != n:
return g
def ecm(n, B1=10000, B2=100000, max_curve=200, seed=1234):
"""Performs factorization using Lenstra's Elliptic curve method.
This function repeatedly calls ``_ecm_one_factor`` to compute the factors
of n. First all the small factors are taken out using trial division.
Then ``_ecm_one_factor`` is used to compute one factor at a time.
Parameters
==========
n : Number to be Factored
B1 : Stage 1 Bound. Must be an even number.
B2 : Stage 2 Bound. Must be an even number.
max_curve : Maximum number of curves generated
seed : Initialize pseudorandom generator
Examples
========
>>> from sympy.ntheory import ecm
>>> ecm(25645121643901801)
{5394769, 4753701529}
>>> ecm(9804659461513846513)
{4641991, 2112166839943}
"""
n = as_int(n)
if B1 % 2 != 0 or B2 % 2 != 0:
raise ValueError("both bounds must be even")
_factors = set()
for prime in sieve.primerange(1, 100000):
if n % prime == 0:
_factors.add(prime)
while(n % prime == 0):
n //= prime
while(n > 1):
factor = _ecm_one_factor(n, B1, B2, max_curve, seed)
if factor is None:
raise ValueError("Increase the bounds")
_factors.add(factor)
n //= factor
factors = set()
for factor in _factors:
if isprime(factor):
factors.add(factor)
continue
factors |= ecm(factor)
return factors
PK ]ZZZmr " sympy/ntheory/egyptian_fraction.pyfrom sympy.core.containers import Tuple
from sympy.core.numbers import (Integer, Rational)
from sympy.core.singleton import S
import sympy.polys
from math import gcd
def egyptian_fraction(r, algorithm="Greedy"):
"""
Return the list of denominators of an Egyptian fraction
expansion [1]_ of the said rational `r`.
Parameters
==========
r : Rational or (p, q)
a positive rational number, ``p/q``.
algorithm : { "Greedy", "Graham Jewett", "Takenouchi", "Golomb" }, optional
Denotes the algorithm to be used (the default is "Greedy").
Examples
========
>>> from sympy import Rational
>>> from sympy.ntheory.egyptian_fraction import egyptian_fraction
>>> egyptian_fraction(Rational(3, 7))
[3, 11, 231]
>>> egyptian_fraction((3, 7), "Graham Jewett")
[7, 8, 9, 56, 57, 72, 3192]
>>> egyptian_fraction((3, 7), "Takenouchi")
[4, 7, 28]
>>> egyptian_fraction((3, 7), "Golomb")
[3, 15, 35]
>>> egyptian_fraction((11, 5), "Golomb")
[1, 2, 3, 4, 9, 234, 1118, 2580]
See Also
========
sympy.core.numbers.Rational
Notes
=====
Currently the following algorithms are supported:
1) Greedy Algorithm
Also called the Fibonacci-Sylvester algorithm [2]_.
At each step, extract the largest unit fraction less
than the target and replace the target with the remainder.
It has some distinct properties:
a) Given `p/q` in lowest terms, generates an expansion of maximum
length `p`. Even as the numerators get large, the number of
terms is seldom more than a handful.
b) Uses minimal memory.
c) The terms can blow up (standard examples of this are 5/121 and
31/311). The denominator is at most squared at each step
(doubly-exponential growth) and typically exhibits
singly-exponential growth.
2) Graham Jewett Algorithm
The algorithm suggested by the result of Graham and Jewett.
Note that this has a tendency to blow up: the length of the
resulting expansion is always ``2**(x/gcd(x, y)) - 1``. See [3]_.
3) Takenouchi Algorithm
The algorithm suggested by Takenouchi (1921).
Differs from the Graham-Jewett algorithm only in the handling
of duplicates. See [3]_.
4) Golomb's Algorithm
A method given by Golumb (1962), using modular arithmetic and
inverses. It yields the same results as a method using continued
fractions proposed by Bleicher (1972). See [4]_.
If the given rational is greater than or equal to 1, a greedy algorithm
of summing the harmonic sequence 1/1 + 1/2 + 1/3 + ... is used, taking
all the unit fractions of this sequence until adding one more would be
greater than the given number. This list of denominators is prefixed
to the result from the requested algorithm used on the remainder. For
example, if r is 8/3, using the Greedy algorithm, we get [1, 2, 3, 4,
5, 6, 7, 14, 420], where the beginning of the sequence, [1, 2, 3, 4, 5,
6, 7] is part of the harmonic sequence summing to 363/140, leaving a
remainder of 31/420, which yields [14, 420] by the Greedy algorithm.
The result of egyptian_fraction(Rational(8, 3), "Golomb") is [1, 2, 3,
4, 5, 6, 7, 14, 574, 2788, 6460, 11590, 33062, 113820], and so on.
References
==========
.. [1] https://en.wikipedia.org/wiki/Egyptian_fraction
.. [2] https://en.wikipedia.org/wiki/Greedy_algorithm_for_Egyptian_fractions
.. [3] https://www.ics.uci.edu/~eppstein/numth/egypt/conflict.html
.. [4] https://web.archive.org/web/20180413004012/https://ami.ektf.hu/uploads/papers/finalpdf/AMI_42_from129to134.pdf
"""
if not isinstance(r, Rational):
if isinstance(r, (Tuple, tuple)) and len(r) == 2:
r = Rational(*r)
else:
raise ValueError("Value must be a Rational or tuple of ints")
if r <= 0:
raise ValueError("Value must be positive")
# common cases that all methods agree on
x, y = r.as_numer_denom()
if y == 1 and x == 2:
return [Integer(i) for i in [1, 2, 3, 6]]
if x == y + 1:
return [S.One, y]
prefix, rem = egypt_harmonic(r)
if rem == 0:
return prefix
# work in Python ints
x, y = rem.p, rem.q
# assert x < y and gcd(x, y) = 1
if algorithm == "Greedy":
postfix = egypt_greedy(x, y)
elif algorithm == "Graham Jewett":
postfix = egypt_graham_jewett(x, y)
elif algorithm == "Takenouchi":
postfix = egypt_takenouchi(x, y)
elif algorithm == "Golomb":
postfix = egypt_golomb(x, y)
else:
raise ValueError("Entered invalid algorithm")
return prefix + [Integer(i) for i in postfix]
def egypt_greedy(x, y):
# assumes gcd(x, y) == 1
if x == 1:
return [y]
else:
a = (-y) % x
b = y*(y//x + 1)
c = gcd(a, b)
if c > 1:
num, denom = a//c, b//c
else:
num, denom = a, b
return [y//x + 1] + egypt_greedy(num, denom)
def egypt_graham_jewett(x, y):
# assumes gcd(x, y) == 1
l = [y] * x
# l is now a list of integers whose reciprocals sum to x/y.
# we shall now proceed to manipulate the elements of l without
# changing the reciprocated sum until all elements are unique.
while len(l) != len(set(l)):
l.sort() # so the list has duplicates. find a smallest pair
for i in range(len(l) - 1):
if l[i] == l[i + 1]:
break
# we have now identified a pair of identical
# elements: l[i] and l[i + 1].
# now comes the application of the result of graham and jewett:
l[i + 1] = l[i] + 1
# and we just iterate that until the list has no duplicates.
l.append(l[i]*(l[i] + 1))
return sorted(l)
def egypt_takenouchi(x, y):
# assumes gcd(x, y) == 1
# special cases for 3/y
if x == 3:
if y % 2 == 0:
return [y//2, y]
i = (y - 1)//2
j = i + 1
k = j + i
return [j, k, j*k]
l = [y] * x
while len(l) != len(set(l)):
l.sort()
for i in range(len(l) - 1):
if l[i] == l[i + 1]:
break
k = l[i]
if k % 2 == 0:
l[i] = l[i] // 2
del l[i + 1]
else:
l[i], l[i + 1] = (k + 1)//2, k*(k + 1)//2
return sorted(l)
def egypt_golomb(x, y):
# assumes x < y and gcd(x, y) == 1
if x == 1:
return [y]
xp = sympy.polys.ZZ.invert(int(x), int(y))
rv = [xp*y]
rv.extend(egypt_golomb((x*xp - 1)//y, xp))
return sorted(rv)
def egypt_harmonic(r):
# assumes r is Rational
rv = []
d = S.One
acc = S.Zero
while acc + 1/d <= r:
acc += 1/d
rv.append(d)
d += 1
return (rv, r - acc)
PK ]ZZZ&Ax4- - sympy/ntheory/elliptic_curve.pyfrom sympy.core.numbers import oo
from sympy.core.symbol import symbols
from sympy.polys.domains import FiniteField, QQ, RationalField, FF
from sympy.polys.polytools import Poly
from sympy.solvers.solvers import solve
from sympy.utilities.iterables import is_sequence
from sympy.utilities.misc import as_int
from .factor_ import divisors
from .residue_ntheory import polynomial_congruence
class EllipticCurve:
"""
Create the following Elliptic Curve over domain.
`y^{2} + a_{1} x y + a_{3} y = x^{3} + a_{2} x^{2} + a_{4} x + a_{6}`
The default domain is ``QQ``. If no coefficient ``a1``, ``a2``, ``a3``,
is given then it creates a curve with the following form:
`y^{2} = x^{3} + a_{4} x + a_{6}`
Examples
========
References
==========
.. [1] J. Silverman "A Friendly Introduction to Number Theory" Third Edition
.. [2] https://mathworld.wolfram.com/EllipticDiscriminant.html
.. [3] G. Hardy, E. Wright "An Introduction to the Theory of Numbers" Sixth Edition
"""
def __init__(self, a4, a6, a1=0, a2=0, a3=0, modulus=0):
if modulus == 0:
domain = QQ
else:
domain = FF(modulus)
a1, a2, a3, a4, a6 = map(domain.convert, (a1, a2, a3, a4, a6))
self._domain = domain
self.modulus = modulus
# Calculate discriminant
b2 = a1**2 + 4 * a2
b4 = 2 * a4 + a1 * a3
b6 = a3**2 + 4 * a6
b8 = a1**2 * a6 + 4 * a2 * a6 - a1 * a3 * a4 + a2 * a3**2 - a4**2
self._b2, self._b4, self._b6, self._b8 = b2, b4, b6, b8
self._discrim = -b2**2 * b8 - 8 * b4**3 - 27 * b6**2 + 9 * b2 * b4 * b6
self._a1 = a1
self._a2 = a2
self._a3 = a3
self._a4 = a4
self._a6 = a6
x, y, z = symbols('x y z')
self.x, self.y, self.z = x, y, z
self._poly = Poly(y**2*z + a1*x*y*z + a3*y*z**2 - x**3 - a2*x**2*z - a4*x*z**2 - a6*z**3, domain=domain)
if isinstance(self._domain, FiniteField):
self._rank = 0
elif isinstance(self._domain, RationalField):
self._rank = None
def __call__(self, x, y, z=1):
return EllipticCurvePoint(x, y, z, self)
def __contains__(self, point):
if is_sequence(point):
if len(point) == 2:
z1 = 1
else:
z1 = point[2]
x1, y1 = point[:2]
elif isinstance(point, EllipticCurvePoint):
x1, y1, z1 = point.x, point.y, point.z
else:
raise ValueError('Invalid point.')
if self.characteristic == 0 and z1 == 0:
return True
return self._poly.subs({self.x: x1, self.y: y1, self.z: z1}) == 0
def __repr__(self):
return self._poly.__repr__()
def minimal(self):
"""
Return minimal Weierstrass equation.
Examples
========
>>> from sympy.ntheory.elliptic_curve import EllipticCurve
>>> e1 = EllipticCurve(-10, -20, 0, -1, 1)
>>> e1.minimal()
Poly(-x**3 + 13392*x*z**2 + y**2*z + 1080432*z**3, x, y, z, domain='QQ')
"""
char = self.characteristic
if char == 2:
return self
if char == 3:
return EllipticCurve(self._b4/2, self._b6/4, a2=self._b2/4, modulus=self.modulus)
c4 = self._b2**2 - 24*self._b4
c6 = -self._b2**3 + 36*self._b2*self._b4 - 216*self._b6
return EllipticCurve(-27*c4, -54*c6, modulus=self.modulus)
def points(self):
"""
Return points of curve over Finite Field.
Examples
========
>>> from sympy.ntheory.elliptic_curve import EllipticCurve
>>> e2 = EllipticCurve(1, 1, 1, 1, 1, modulus=5)
>>> e2.points()
{(0, 2), (1, 4), (2, 0), (2, 2), (3, 0), (3, 1), (4, 0)}
"""
char = self.characteristic
all_pt = set()
if char >= 1:
for i in range(char):
congruence_eq = self._poly.subs({self.x: i, self.z: 1}).expr
sol = polynomial_congruence(congruence_eq, char)
all_pt.update((i, num) for num in sol)
return all_pt
else:
raise ValueError("Infinitely many points")
def points_x(self, x):
"""Returns points on the curve for the given x-coordinate."""
pt = []
if self._domain == QQ:
for y in solve(self._poly.subs(self.x, x)):
pt.append((x, y))
else:
congruence_eq = self._poly.subs({self.x: x, self.z: 1}).expr
for y in polynomial_congruence(congruence_eq, self.characteristic):
pt.append((x, y))
return pt
def torsion_points(self):
"""
Return torsion points of curve over Rational number.
Return point objects those are finite order.
According to Nagell-Lutz theorem, torsion point p(x, y)
x and y are integers, either y = 0 or y**2 is divisor
of discriminent. According to Mazur's theorem, there are
at most 15 points in torsion collection.
Examples
========
>>> from sympy.ntheory.elliptic_curve import EllipticCurve
>>> e2 = EllipticCurve(-43, 166)
>>> sorted(e2.torsion_points())
[(-5, -16), (-5, 16), O, (3, -8), (3, 8), (11, -32), (11, 32)]
"""
if self.characteristic > 0:
raise ValueError("No torsion point for Finite Field.")
l = [EllipticCurvePoint.point_at_infinity(self)]
for xx in solve(self._poly.subs({self.y: 0, self.z: 1})):
if xx.is_rational:
l.append(self(xx, 0))
for i in divisors(self.discriminant, generator=True):
j = int(i**.5)
if j**2 == i:
for xx in solve(self._poly.subs({self.y: j, self.z: 1})):
if not xx.is_rational:
continue
p = self(xx, j)
if p.order() != oo:
l.extend([p, -p])
return l
@property
def characteristic(self):
"""
Return domain characteristic.
Examples
========
>>> from sympy.ntheory.elliptic_curve import EllipticCurve
>>> e2 = EllipticCurve(-43, 166)
>>> e2.characteristic
0
"""
return self._domain.characteristic()
@property
def discriminant(self):
"""
Return curve discriminant.
Examples
========
>>> from sympy.ntheory.elliptic_curve import EllipticCurve
>>> e2 = EllipticCurve(0, 17)
>>> e2.discriminant
-124848
"""
return int(self._discrim)
@property
def is_singular(self):
"""
Return True if curve discriminant is equal to zero.
"""
return self.discriminant == 0
@property
def j_invariant(self):
"""
Return curve j-invariant.
Examples
========
>>> from sympy.ntheory.elliptic_curve import EllipticCurve
>>> e1 = EllipticCurve(-2, 0, 0, 1, 1)
>>> e1.j_invariant
1404928/389
"""
c4 = self._b2**2 - 24*self._b4
return self._domain.to_sympy(c4**3 / self._discrim)
@property
def order(self):
"""
Number of points in Finite field.
Examples
========
>>> from sympy.ntheory.elliptic_curve import EllipticCurve
>>> e2 = EllipticCurve(1, 0, modulus=19)
>>> e2.order
19
"""
if self.characteristic == 0:
raise NotImplementedError("Still not implemented")
return len(self.points())
@property
def rank(self):
"""
Number of independent points of infinite order.
For Finite field, it must be 0.
"""
if self._rank is not None:
return self._rank
raise NotImplementedError("Still not implemented")
class EllipticCurvePoint:
"""
Point of Elliptic Curve
Examples
========
>>> from sympy.ntheory.elliptic_curve import EllipticCurve
>>> e1 = EllipticCurve(-17, 16)
>>> p1 = e1(0, -4, 1)
>>> p2 = e1(1, 0)
>>> p1 + p2
(15, -56)
>>> e3 = EllipticCurve(-1, 9)
>>> e3(1, -3) * 3
(664/169, 17811/2197)
>>> (e3(1, -3) * 3).order()
oo
>>> e2 = EllipticCurve(-2, 0, 0, 1, 1)
>>> p = e2(-1,1)
>>> q = e2(0, -1)
>>> p+q
(4, 8)
>>> p-q
(1, 0)
>>> 3*p-5*q
(328/361, -2800/6859)
"""
@staticmethod
def point_at_infinity(curve):
return EllipticCurvePoint(0, 1, 0, curve)
def __init__(self, x, y, z, curve):
dom = curve._domain.convert
self.x = dom(x)
self.y = dom(y)
self.z = dom(z)
self._curve = curve
self._domain = self._curve._domain
if not self._curve.__contains__(self):
raise ValueError("The curve does not contain this point")
def __add__(self, p):
if self.z == 0:
return p
if p.z == 0:
return self
x1, y1 = self.x/self.z, self.y/self.z
x2, y2 = p.x/p.z, p.y/p.z
a1 = self._curve._a1
a2 = self._curve._a2
a3 = self._curve._a3
a4 = self._curve._a4
a6 = self._curve._a6
if x1 != x2:
slope = (y1 - y2) / (x1 - x2)
yint = (y1 * x2 - y2 * x1) / (x2 - x1)
else:
if (y1 + y2) == 0:
return self.point_at_infinity(self._curve)
slope = (3 * x1**2 + 2*a2*x1 + a4 - a1*y1) / (a1 * x1 + a3 + 2 * y1)
yint = (-x1**3 + a4*x1 + 2*a6 - a3*y1) / (a1*x1 + a3 + 2*y1)
x3 = slope**2 + a1*slope - a2 - x1 - x2
y3 = -(slope + a1) * x3 - yint - a3
return self._curve(x3, y3, 1)
def __lt__(self, other):
return (self.x, self.y, self.z) < (other.x, other.y, other.z)
def __mul__(self, n):
n = as_int(n)
r = self.point_at_infinity(self._curve)
if n == 0:
return r
if n < 0:
return -self * -n
p = self
while n:
if n & 1:
r = r + p
n >>= 1
p = p + p
return r
def __rmul__(self, n):
return self * n
def __neg__(self):
return EllipticCurvePoint(self.x, -self.y - self._curve._a1*self.x - self._curve._a3, self.z, self._curve)
def __repr__(self):
if self.z == 0:
return 'O'
dom = self._curve._domain
try:
return '({}, {})'.format(dom.to_sympy(self.x), dom.to_sympy(self.y))
except TypeError:
pass
return '({}, {})'.format(self.x, self.y)
def __sub__(self, other):
return self.__add__(-other)
def order(self):
"""
Return point order n where nP = 0.
"""
if self.z == 0:
return 1
if self.y == 0: # P = -P
return 2
p = self * 2
if p.y == -self.y: # 2P = -P
return 3
i = 2
if self._domain != QQ:
while int(p.x) == p.x and int(p.y) == p.y:
p = self + p
i += 1
if p.z == 0:
return i
return oo
while p.x.numerator == p.x and p.y.numerator == p.y:
p = self + p
i += 1
if i > 12:
return oo
if p.z == 0:
return i
return oo
PK ]ZZZ U��0 �0 sympy/ntheory/factor_.py"""
Integer factorization
"""
from collections import defaultdict
import math
from sympy.core.containers import Dict
from sympy.core.mul import Mul
from sympy.core.numbers import Rational, Integer
from sympy.core.intfunc import num_digits
from sympy.core.power import Pow
from sympy.core.random import _randint
from sympy.core.singleton import S
from sympy.external.gmpy import (SYMPY_INTS, gcd, sqrt as isqrt,
sqrtrem, iroot, bit_scan1, remove)
from .primetest import isprime, MERSENNE_PRIME_EXPONENTS, is_mersenne_prime
from .generate import sieve, primerange, nextprime
from .digits import digits
from sympy.utilities.decorator import deprecated
from sympy.utilities.iterables import flatten
from sympy.utilities.misc import as_int, filldedent
from .ecm import _ecm_one_factor
def smoothness(n):
"""
Return the B-smooth and B-power smooth values of n.
The smoothness of n is the largest prime factor of n; the power-
smoothness is the largest divisor raised to its multiplicity.
Examples
========
>>> from sympy.ntheory.factor_ import smoothness
>>> smoothness(2**7*3**2)
(3, 128)
>>> smoothness(2**4*13)
(13, 16)
>>> smoothness(2)
(2, 2)
See Also
========
factorint, smoothness_p
"""
if n == 1:
return (1, 1) # not prime, but otherwise this causes headaches
facs = factorint(n)
return max(facs), max(m**facs[m] for m in facs)
def smoothness_p(n, m=-1, power=0, visual=None):
"""
Return a list of [m, (p, (M, sm(p + m), psm(p + m)))...]
where:
1. p**M is the base-p divisor of n
2. sm(p + m) is the smoothness of p + m (m = -1 by default)
3. psm(p + m) is the power smoothness of p + m
The list is sorted according to smoothness (default) or by power smoothness
if power=1.
The smoothness of the numbers to the left (m = -1) or right (m = 1) of a
factor govern the results that are obtained from the p +/- 1 type factoring
methods.
>>> from sympy.ntheory.factor_ import smoothness_p, factorint
>>> smoothness_p(10431, m=1)
(1, [(3, (2, 2, 4)), (19, (1, 5, 5)), (61, (1, 31, 31))])
>>> smoothness_p(10431)
(-1, [(3, (2, 2, 2)), (19, (1, 3, 9)), (61, (1, 5, 5))])
>>> smoothness_p(10431, power=1)
(-1, [(3, (2, 2, 2)), (61, (1, 5, 5)), (19, (1, 3, 9))])
If visual=True then an annotated string will be returned:
>>> print(smoothness_p(21477639576571, visual=1))
p**i=4410317**1 has p-1 B=1787, B-pow=1787
p**i=4869863**1 has p-1 B=2434931, B-pow=2434931
This string can also be generated directly from a factorization dictionary
and vice versa:
>>> factorint(17*9)
{3: 2, 17: 1}
>>> smoothness_p(_)
'p**i=3**2 has p-1 B=2, B-pow=2\\np**i=17**1 has p-1 B=2, B-pow=16'
>>> smoothness_p(_)
{3: 2, 17: 1}
The table of the output logic is:
====== ====== ======= =======
| Visual
------ ----------------------
Input True False other
====== ====== ======= =======
dict str tuple str
str str tuple dict
tuple str tuple str
n str tuple tuple
mul str tuple tuple
====== ====== ======= =======
See Also
========
factorint, smoothness
"""
# visual must be True, False or other (stored as None)
if visual in (1, 0):
visual = bool(visual)
elif visual not in (True, False):
visual = None
if isinstance(n, str):
if visual:
return n
d = {}
for li in n.splitlines():
k, v = [int(i) for i in
li.split('has')[0].split('=')[1].split('**')]
d[k] = v
if visual is not True and visual is not False:
return d
return smoothness_p(d, visual=False)
elif not isinstance(n, tuple):
facs = factorint(n, visual=False)
if power:
k = -1
else:
k = 1
if isinstance(n, tuple):
rv = n
else:
rv = (m, sorted([(f,
tuple([M] + list(smoothness(f + m))))
for f, M in list(facs.items())],
key=lambda x: (x[1][k], x[0])))
if visual is False or (visual is not True) and (type(n) in [int, Mul]):
return rv
lines = []
for dat in rv[1]:
dat = flatten(dat)
dat.insert(2, m)
lines.append('p**i=%i**%i has p%+i B=%i, B-pow=%i' % tuple(dat))
return '\n'.join(lines)
def multiplicity(p, n):
"""
Find the greatest integer m such that p**m divides n.
Examples
========
>>> from sympy import multiplicity, Rational
>>> [multiplicity(5, n) for n in [8, 5, 25, 125, 250]]
[0, 1, 2, 3, 3]
>>> multiplicity(3, Rational(1, 9))
-2
Note: when checking for the multiplicity of a number in a
large factorial it is most efficient to send it as an unevaluated
factorial or to call ``multiplicity_in_factorial`` directly:
>>> from sympy.ntheory import multiplicity_in_factorial
>>> from sympy import factorial
>>> p = factorial(25)
>>> n = 2**100
>>> nfac = factorial(n, evaluate=False)
>>> multiplicity(p, nfac)
52818775009509558395695966887
>>> _ == multiplicity_in_factorial(p, n)
True
See Also
========
trailing
"""
try:
p, n = as_int(p), as_int(n)
except ValueError:
from sympy.functions.combinatorial.factorials import factorial
if all(isinstance(i, (SYMPY_INTS, Rational)) for i in (p, n)):
p = Rational(p)
n = Rational(n)
if p.q == 1:
if n.p == 1:
return -multiplicity(p.p, n.q)
return multiplicity(p.p, n.p) - multiplicity(p.p, n.q)
elif p.p == 1:
return multiplicity(p.q, n.q)
else:
like = min(
multiplicity(p.p, n.p),
multiplicity(p.q, n.q))
cross = min(
multiplicity(p.q, n.p),
multiplicity(p.p, n.q))
return like - cross
elif (isinstance(p, (SYMPY_INTS, Integer)) and
isinstance(n, factorial) and
isinstance(n.args[0], Integer) and
n.args[0] >= 0):
return multiplicity_in_factorial(p, n.args[0])
raise ValueError('expecting ints or fractions, got %s and %s' % (p, n))
if n == 0:
raise ValueError('no such integer exists: multiplicity of %s is not-defined' %(n))
return remove(n, p)[1]
def multiplicity_in_factorial(p, n):
"""return the largest integer ``m`` such that ``p**m`` divides ``n!``
without calculating the factorial of ``n``.
Parameters
==========
p : Integer
positive integer
n : Integer
non-negative integer
Examples
========
>>> from sympy.ntheory import multiplicity_in_factorial
>>> from sympy import factorial
>>> multiplicity_in_factorial(2, 3)
1
An instructive use of this is to tell how many trailing zeros
a given factorial has. For example, there are 6 in 25!:
>>> factorial(25)
15511210043330985984000000
>>> multiplicity_in_factorial(10, 25)
6
For large factorials, it is much faster/feasible to use
this function rather than computing the actual factorial:
>>> multiplicity_in_factorial(factorial(25), 2**100)
52818775009509558395695966887
See Also
========
multiplicity
"""
p, n = as_int(p), as_int(n)
if p <= 0:
raise ValueError('expecting positive integer got %s' % p )
if n < 0:
raise ValueError('expecting non-negative integer got %s' % n )
# keep only the largest of a given multiplicity since those
# of a given multiplicity will be goverened by the behavior
# of the largest factor
f = defaultdict(int)
for k, v in factorint(p).items():
f[v] = max(k, f[v])
# multiplicity of p in n! depends on multiplicity
# of prime `k` in p, so we floor divide by `v`
# and keep it if smaller than the multiplicity of p
# seen so far
return min((n + k - sum(digits(n, k)))//(k - 1)//v for v, k in f.items())
def _perfect_power(n, next_p=2):
""" Return integers ``(b, e)`` such that ``n == b**e`` if ``n`` is a unique
perfect power with ``e > 1``, else ``False`` (e.g. 1 is not a perfect power).
Explanation
===========
This is a low-level helper for ``perfect_power``, for internal use.
Parameters
==========
n : int
assume that n is a nonnegative integer
next_p : int
Assume that n has no factor less than next_p.
i.e., all(n % p for p in range(2, next_p)) is True
Examples
========
>>> from sympy.ntheory.factor_ import _perfect_power
>>> _perfect_power(16)
(2, 4)
>>> _perfect_power(17)
False
"""
if n <= 3:
return False
factors = {}
g = 0
multi = 1
def done(n, factors, g, multi):
g = gcd(g, multi)
if g == 1:
return False
factors[n] = multi
return math.prod(p**(e//g) for p, e in factors.items()), g
# If n is small, only trial factoring is faster
if n <= 1_000_000:
n = _factorint_small(factors, n, 1_000, 1_000, next_p)[0]
if n > 1:
return False
g = gcd(*factors.values())
if g == 1:
return False
return math.prod(p**(e//g) for p, e in factors.items()), g
# divide by 2
if next_p < 3:
g = bit_scan1(n)
if g:
if g == 1:
return False
n >>= g
factors[2] = g
if n == 1:
return 2, g
else:
# If `m**g`, then we have found perfect power.
# Otherwise, there is no possibility of perfect power, especially if `g` is prime.
m, _exact = iroot(n, g)
if _exact:
return 2*m, g
elif isprime(g):
return False
next_p = 3
# square number?
while n & 7 == 1: # n % 8 == 1:
m, _exact = iroot(n, 2)
if _exact:
n = m
multi <<= 1
else:
break
if n < next_p**3:
return done(n, factors, g, multi)
# trial factoring
# Since the maximum value an exponent can take is `log_{next_p}(n)`,
# the number of exponents to be checked can be reduced by performing a trial factoring.
# The value of `tf_max` needs more consideration.
tf_max = n.bit_length()//27 + 24
if next_p < tf_max:
for p in primerange(next_p, tf_max):
m, t = remove(n, p)
if t:
n = m
t *= multi
_g = gcd(g, t)
if _g == 1:
return False
factors[p] = t
if n == 1:
return math.prod(p**(e//_g)
for p, e in factors.items()), _g
elif g == 0 or _g < g: # If g is updated
g = _g
m, _exact = iroot(n**multi, g)
if _exact:
return m * math.prod(p**(e//g)
for p, e in factors.items()), g
elif isprime(g):
return False
next_p = tf_max
if n < next_p**3:
return done(n, factors, g, multi)
# check iroot
if g:
# If g is non-zero, the exponent is a divisor of g.
# 2 can be omitted since it has already been checked.
prime_iter = sorted(factorint(g >> bit_scan1(g)).keys())
else:
# The maximum possible value of the exponent is `log_{next_p}(n)`.
# To compensate for the presence of computational error, 2 is added.
prime_iter = primerange(3, int(math.log(n, next_p)) + 2)
logn = math.log2(n)
threshold = logn / 40 # Threshold for direct calculation
for p in prime_iter:
if threshold < p:
# If p is large, find the power root p directly without `iroot`.
while True:
b = pow(2, logn / p)
rb = int(b + 0.5)
if abs(rb - b) < 0.01 and rb**p == n:
n = rb
multi *= p
logn = math.log2(n)
else:
break
else:
while True:
m, _exact = iroot(n, p)
if _exact:
n = m
multi *= p
logn = math.log2(n)
else:
break
if n < next_p**(p + 2):
break
return done(n, factors, g, multi)
def perfect_power(n, candidates=None, big=True, factor=True):
"""
Return ``(b, e)`` such that ``n`` == ``b**e`` if ``n`` is a unique
perfect power with ``e > 1``, else ``False`` (e.g. 1 is not a
perfect power). A ValueError is raised if ``n`` is not Rational.
By default, the base is recursively decomposed and the exponents
collected so the largest possible ``e`` is sought. If ``big=False``
then the smallest possible ``e`` (thus prime) will be chosen.
If ``factor=True`` then simultaneous factorization of ``n`` is
attempted since finding a factor indicates the only possible root
for ``n``. This is True by default since only a few small factors will
be tested in the course of searching for the perfect power.
The use of ``candidates`` is primarily for internal use; if provided,
False will be returned if ``n`` cannot be written as a power with one
of the candidates as an exponent and factoring (beyond testing for
a factor of 2) will not be attempted.
Examples
========
>>> from sympy import perfect_power, Rational
>>> perfect_power(16)
(2, 4)
>>> perfect_power(16, big=False)
(4, 2)
Negative numbers can only have odd perfect powers:
>>> perfect_power(-4)
False
>>> perfect_power(-8)
(-2, 3)
Rationals are also recognized:
>>> perfect_power(Rational(1, 2)**3)
(1/2, 3)
>>> perfect_power(Rational(-3, 2)**3)
(-3/2, 3)
Notes
=====
To know whether an integer is a perfect power of 2 use
>>> is2pow = lambda n: bool(n and not n & (n - 1))
>>> [(i, is2pow(i)) for i in range(5)]
[(0, False), (1, True), (2, True), (3, False), (4, True)]
It is not necessary to provide ``candidates``. When provided
it will be assumed that they are ints. The first one that is
larger than the computed maximum possible exponent will signal
failure for the routine.
>>> perfect_power(3**8, [9])
False
>>> perfect_power(3**8, [2, 4, 8])
(3, 8)
>>> perfect_power(3**8, [4, 8], big=False)
(9, 4)
See Also
========
sympy.core.intfunc.integer_nthroot
sympy.ntheory.primetest.is_square
"""
if isinstance(n, Rational) and not n.is_Integer:
p, q = n.as_numer_denom()
if p is S.One:
pp = perfect_power(q)
if pp:
pp = (n.func(1, pp[0]), pp[1])
else:
pp = perfect_power(p)
if pp:
num, e = pp
pq = perfect_power(q, [e])
if pq:
den, _ = pq
pp = n.func(num, den), e
return pp
n = as_int(n)
if n < 0:
pp = perfect_power(-n)
if pp:
b, e = pp
if e % 2:
return -b, e
return False
if candidates is None and big:
return _perfect_power(n)
if n <= 3:
# no unique exponent for 0, 1
# 2 and 3 have exponents of 1
return False
logn = math.log2(n)
max_possible = int(logn) + 2 # only check values less than this
not_square = n % 10 in [2, 3, 7, 8] # squares cannot end in 2, 3, 7, 8
min_possible = 2 + not_square
if not candidates:
candidates = primerange(min_possible, max_possible)
else:
candidates = sorted([i for i in candidates
if min_possible <= i < max_possible])
if n%2 == 0:
e = bit_scan1(n)
candidates = [i for i in candidates if e%i == 0]
if big:
candidates = reversed(candidates)
for e in candidates:
r, ok = iroot(n, e)
if ok:
return int(r), e
return False
def _factors():
rv = 2 + n % 2
while True:
yield rv
rv = nextprime(rv)
for fac, e in zip(_factors(), candidates):
# see if there is a factor present
if factor and n % fac == 0:
# find what the potential power is
e = remove(n, fac)[1]
# if it's a trivial power we are done
if e == 1:
return False
# maybe the e-th root of n is exact
r, exact = iroot(n, e)
if not exact:
# Having a factor, we know that e is the maximal
# possible value for a root of n.
# If n = fac**e*m can be written as a perfect
# power then see if m can be written as r**E where
# gcd(e, E) != 1 so n = (fac**(e//E)*r)**E
m = n//fac**e
rE = perfect_power(m, candidates=divisors(e, generator=True))
if not rE:
return False
else:
r, E = rE
r, e = fac**(e//E)*r, E
if not big:
e0 = primefactors(e)
if e0[0] != e:
r, e = r**(e//e0[0]), e0[0]
return int(r), e
# Weed out downright impossible candidates
if logn/e < 40:
b = 2.0**(logn/e)
if abs(int(b + 0.5) - b) > 0.01:
continue
# now see if the plausible e makes a perfect power
r, exact = iroot(n, e)
if exact:
if big:
m = perfect_power(r, big=big, factor=factor)
if m:
r, e = m[0], e*m[1]
return int(r), e
return False
def pollard_rho(n, s=2, a=1, retries=5, seed=1234, max_steps=None, F=None):
r"""
Use Pollard's rho method to try to extract a nontrivial factor
of ``n``. The returned factor may be a composite number. If no
factor is found, ``None`` is returned.
The algorithm generates pseudo-random values of x with a generator
function, replacing x with F(x). If F is not supplied then the
function x**2 + ``a`` is used. The first value supplied to F(x) is ``s``.
Upon failure (if ``retries`` is > 0) a new ``a`` and ``s`` will be
supplied; the ``a`` will be ignored if F was supplied.
The sequence of numbers generated by such functions generally have a
a lead-up to some number and then loop around back to that number and
begin to repeat the sequence, e.g. 1, 2, 3, 4, 5, 3, 4, 5 -- this leader
and loop look a bit like the Greek letter rho, and thus the name, 'rho'.
For a given function, very different leader-loop values can be obtained
so it is a good idea to allow for retries:
>>> from sympy.ntheory.generate import cycle_length
>>> n = 16843009
>>> F = lambda x:(2048*pow(x, 2, n) + 32767) % n
>>> for s in range(5):
... print('loop length = %4i; leader length = %3i' % next(cycle_length(F, s)))
...
loop length = 2489; leader length = 43
loop length = 78; leader length = 121
loop length = 1482; leader length = 100
loop length = 1482; leader length = 286
loop length = 1482; leader length = 101
Here is an explicit example where there is a three element leadup to
a sequence of 3 numbers (11, 14, 4) that then repeat:
>>> x=2
>>> for i in range(9):
... print(x)
... x=(x**2+12)%17
...
2
16
13
11
14
4
11
14
4
>>> next(cycle_length(lambda x: (x**2+12)%17, 2))
(3, 3)
>>> list(cycle_length(lambda x: (x**2+12)%17, 2, values=True))
[2, 16, 13, 11, 14, 4]
Instead of checking the differences of all generated values for a gcd
with n, only the kth and 2*kth numbers are checked, e.g. 1st and 2nd,
2nd and 4th, 3rd and 6th until it has been detected that the loop has been
traversed. Loops may be many thousands of steps long before rho finds a
factor or reports failure. If ``max_steps`` is specified, the iteration
is cancelled with a failure after the specified number of steps.
Examples
========
>>> from sympy import pollard_rho
>>> n=16843009
>>> F=lambda x:(2048*pow(x,2,n) + 32767) % n
>>> pollard_rho(n, F=F)
257
Use the default setting with a bad value of ``a`` and no retries:
>>> pollard_rho(n, a=n-2, retries=0)
If retries is > 0 then perhaps the problem will correct itself when
new values are generated for a:
>>> pollard_rho(n, a=n-2, retries=1)
257
References
==========
.. [1] Richard Crandall & Carl Pomerance (2005), "Prime Numbers:
A Computational Perspective", Springer, 2nd edition, 229-231
"""
n = int(n)
if n < 5:
raise ValueError('pollard_rho should receive n > 4')
randint = _randint(seed + retries)
V = s
for i in range(retries + 1):
U = V
if not F:
F = lambda x: (pow(x, 2, n) + a) % n
j = 0
while 1:
if max_steps and (j > max_steps):
break
j += 1
U = F(U)
V = F(F(V)) # V is 2x further along than U
g = gcd(U - V, n)
if g == 1:
continue
if g == n:
break
return int(g)
V = randint(0, n - 1)
a = randint(1, n - 3) # for x**2 + a, a%n should not be 0 or -2
F = None
return None
def pollard_pm1(n, B=10, a=2, retries=0, seed=1234):
"""
Use Pollard's p-1 method to try to extract a nontrivial factor
of ``n``. Either a divisor (perhaps composite) or ``None`` is returned.
The value of ``a`` is the base that is used in the test gcd(a**M - 1, n).
The default is 2. If ``retries`` > 0 then if no factor is found after the
first attempt, a new ``a`` will be generated randomly (using the ``seed``)
and the process repeated.
Note: the value of M is lcm(1..B) = reduce(ilcm, range(2, B + 1)).
A search is made for factors next to even numbers having a power smoothness
less than ``B``. Choosing a larger B increases the likelihood of finding a
larger factor but takes longer. Whether a factor of n is found or not
depends on ``a`` and the power smoothness of the even number just less than
the factor p (hence the name p - 1).
Although some discussion of what constitutes a good ``a`` some
descriptions are hard to interpret. At the modular.math site referenced
below it is stated that if gcd(a**M - 1, n) = N then a**M % q**r is 1
for every prime power divisor of N. But consider the following:
>>> from sympy.ntheory.factor_ import smoothness_p, pollard_pm1
>>> n=257*1009
>>> smoothness_p(n)
(-1, [(257, (1, 2, 256)), (1009, (1, 7, 16))])
So we should (and can) find a root with B=16:
>>> pollard_pm1(n, B=16, a=3)
1009
If we attempt to increase B to 256 we find that it does not work:
>>> pollard_pm1(n, B=256)
>>>
But if the value of ``a`` is changed we find that only multiples of
257 work, e.g.:
>>> pollard_pm1(n, B=256, a=257)
1009
Checking different ``a`` values shows that all the ones that did not
work had a gcd value not equal to ``n`` but equal to one of the
factors:
>>> from sympy import ilcm, igcd, factorint, Pow
>>> M = 1
>>> for i in range(2, 256):
... M = ilcm(M, i)
...
>>> set([igcd(pow(a, M, n) - 1, n) for a in range(2, 256) if
... igcd(pow(a, M, n) - 1, n) != n])
{1009}
But does aM % d for every divisor of n give 1?
>>> aM = pow(255, M, n)
>>> [(d, aM%Pow(*d.args)) for d in factorint(n, visual=True).args]
[(257**1, 1), (1009**1, 1)]
No, only one of them. So perhaps the principle is that a root will
be found for a given value of B provided that:
1) the power smoothness of the p - 1 value next to the root
does not exceed B
2) a**M % p != 1 for any of the divisors of n.
By trying more than one ``a`` it is possible that one of them
will yield a factor.
Examples
========
With the default smoothness bound, this number cannot be cracked:
>>> from sympy.ntheory import pollard_pm1
>>> pollard_pm1(21477639576571)
Increasing the smoothness bound helps:
>>> pollard_pm1(21477639576571, B=2000)
4410317
Looking at the smoothness of the factors of this number we find:
>>> from sympy.ntheory.factor_ import smoothness_p, factorint
>>> print(smoothness_p(21477639576571, visual=1))
p**i=4410317**1 has p-1 B=1787, B-pow=1787
p**i=4869863**1 has p-1 B=2434931, B-pow=2434931
The B and B-pow are the same for the p - 1 factorizations of the divisors
because those factorizations had a very large prime factor:
>>> factorint(4410317 - 1)
{2: 2, 617: 1, 1787: 1}
>>> factorint(4869863-1)
{2: 1, 2434931: 1}
Note that until B reaches the B-pow value of 1787, the number is not cracked;
>>> pollard_pm1(21477639576571, B=1786)
>>> pollard_pm1(21477639576571, B=1787)
4410317
The B value has to do with the factors of the number next to the divisor,
not the divisors themselves. A worst case scenario is that the number next
to the factor p has a large prime divisisor or is a perfect power. If these
conditions apply then the power-smoothness will be about p/2 or p. The more
realistic is that there will be a large prime factor next to p requiring
a B value on the order of p/2. Although primes may have been searched for
up to this level, the p/2 is a factor of p - 1, something that we do not
know. The modular.math reference below states that 15% of numbers in the
range of 10**15 to 15**15 + 10**4 are 10**6 power smooth so a B of 10**6
will fail 85% of the time in that range. From 10**8 to 10**8 + 10**3 the
percentages are nearly reversed...but in that range the simple trial
division is quite fast.
References
==========
.. [1] Richard Crandall & Carl Pomerance (2005), "Prime Numbers:
A Computational Perspective", Springer, 2nd edition, 236-238
.. [2] https://web.archive.org/web/20150716201437/http://modular.math.washington.edu/edu/2007/spring/ent/ent-html/node81.html
.. [3] https://www.cs.toronto.edu/~yuvalf/Factorization.pdf
"""
n = int(n)
if n < 4 or B < 3:
raise ValueError('pollard_pm1 should receive n > 3 and B > 2')
randint = _randint(seed + B)
# computing a**lcm(1,2,3,..B) % n for B > 2
# it looks weird, but it's right: primes run [2, B]
# and the answer's not right until the loop is done.
for i in range(retries + 1):
aM = a
for p in sieve.primerange(2, B + 1):
e = int(math.log(B, p))
aM = pow(aM, pow(p, e), n)
g = gcd(aM - 1, n)
if 1 < g < n:
return int(g)
# get a new a:
# since the exponent, lcm(1..B), is even, if we allow 'a' to be 'n-1'
# then (n - 1)**even % n will be 1 which will give a g of 0 and 1 will
# give a zero, too, so we set the range as [2, n-2]. Some references
# say 'a' should be coprime to n, but either will detect factors.
a = randint(2, n - 2)
def _trial(factors, n, candidates, verbose=False):
"""
Helper function for integer factorization. Trial factors ``n`
against all integers given in the sequence ``candidates``
and updates the dict ``factors`` in-place. Returns the reduced
value of ``n`` and a flag indicating whether any factors were found.
"""
if verbose:
factors0 = list(factors.keys())
nfactors = len(factors)
for d in candidates:
if n % d == 0:
n, m = remove(n // d, d)
factors[d] = m + 1
if verbose:
for k in sorted(set(factors).difference(set(factors0))):
print(factor_msg % (k, factors[k]))
return int(n), len(factors) != nfactors
def _check_termination(factors, n, limit, use_trial, use_rho, use_pm1,
verbose, next_p):
"""
Helper function for integer factorization. Checks if ``n``
is a prime or a perfect power, and in those cases updates the factorization.
"""
if verbose:
print('Check for termination')
if n == 1:
if verbose:
print(complete_msg)
return True
if n < next_p**2 or isprime(n):
factors[int(n)] = 1
if verbose:
print(complete_msg)
return True
# since we've already been factoring there is no need to do
# simultaneous factoring with the power check
p = _perfect_power(n, next_p)
if not p:
return False
base, exp = p
if base < next_p**2 or isprime(base):
factors[base] = exp
else:
facs = factorint(base, limit, use_trial, use_rho, use_pm1,
verbose=False)
for b, e in facs.items():
if verbose:
print(factor_msg % (b, e))
# int() can be removed when https://github.com/flintlib/python-flint/issues/92 is resolved
factors[b] = int(exp*e)
if verbose:
print(complete_msg)
return True
trial_int_msg = "Trial division with ints [%i ... %i] and fail_max=%i"
trial_msg = "Trial division with primes [%i ... %i]"
rho_msg = "Pollard's rho with retries %i, max_steps %i and seed %i"
pm1_msg = "Pollard's p-1 with smoothness bound %i and seed %i"
ecm_msg = "Elliptic Curve with B1 bound %i, B2 bound %i, num_curves %i"
factor_msg = '\t%i ** %i'
fermat_msg = 'Close factors satisying Fermat condition found.'
complete_msg = 'Factorization is complete.'
def _factorint_small(factors, n, limit, fail_max, next_p=2):
"""
Return the value of n and either a 0 (indicating that factorization up
to the limit was complete) or else the next near-prime that would have
been tested.
Factoring stops if there are fail_max unsuccessful tests in a row.
If factors of n were found they will be in the factors dictionary as
{factor: multiplicity} and the returned value of n will have had those
factors removed. The factors dictionary is modified in-place.
"""
def done(n, d):
"""return n, d if the sqrt(n) was not reached yet, else
n, 0 indicating that factoring is done.
"""
if d*d <= n:
return n, d
return n, 0
limit2 = limit**2
threshold2 = min(n, limit2)
if next_p < 3:
if not n & 1:
m = bit_scan1(n)
factors[2] = m
n >>= m
threshold2 = min(n, limit2)
next_p = 3
if threshold2 < 9: # next_p**2 = 9
return done(n, next_p)
if next_p < 5:
if not n % 3:
n //= 3
m = 1
while not n % 3:
n //= 3
m += 1
if m == 20:
n, mm = remove(n, 3)
m += mm
break
factors[3] = m
threshold2 = min(n, limit2)
next_p = 5
if threshold2 < 25: # next_p**2 = 25
return done(n, next_p)
# Because of the order of checks, starting from `min_p = 6k+5`,
# useless checks are caused.
# We want to calculate
# next_p += [-1, -2, 3, 2, 1, 0][next_p % 6]
p6 = next_p % 6
next_p += (-1 if p6 < 2 else 5) - p6
fails = 0
while fails < fail_max:
# next_p % 6 == 5
if n % next_p:
fails += 1
else:
n //= next_p
m = 1
while not n % next_p:
n //= next_p
m += 1
if m == 20:
n, mm = remove(n, next_p)
m += mm
break
factors[next_p] = m
fails = 0
threshold2 = min(n, limit2)
next_p += 2
if threshold2 < next_p**2:
return done(n, next_p)
# next_p % 6 == 1
if n % next_p:
fails += 1
else:
n //= next_p
m = 1
while not n % next_p:
n //= next_p
m += 1
if m == 20:
n, mm = remove(n, next_p)
m += mm
break
factors[next_p] = m
fails = 0
threshold2 = min(n, limit2)
next_p += 4
if threshold2 < next_p**2:
return done(n, next_p)
return done(n, next_p)
def factorint(n, limit=None, use_trial=True, use_rho=True, use_pm1=True,
use_ecm=True, verbose=False, visual=None, multiple=False):
r"""
Given a positive integer ``n``, ``factorint(n)`` returns a dict containing
the prime factors of ``n`` as keys and their respective multiplicities
as values. For example:
>>> from sympy.ntheory import factorint
>>> factorint(2000) # 2000 = (2**4) * (5**3)
{2: 4, 5: 3}
>>> factorint(65537) # This number is prime
{65537: 1}
For input less than 2, factorint behaves as follows:
- ``factorint(1)`` returns the empty factorization, ``{}``
- ``factorint(0)`` returns ``{0:1}``
- ``factorint(-n)`` adds ``-1:1`` to the factors and then factors ``n``
Partial Factorization:
If ``limit`` (> 3) is specified, the search is stopped after performing
trial division up to (and including) the limit (or taking a
corresponding number of rho/p-1 steps). This is useful if one has
a large number and only is interested in finding small factors (if
any). Note that setting a limit does not prevent larger factors
from being found early; it simply means that the largest factor may
be composite. Since checking for perfect power is relatively cheap, it is
done regardless of the limit setting.
This number, for example, has two small factors and a huge
semi-prime factor that cannot be reduced easily:
>>> from sympy.ntheory import isprime
>>> a = 1407633717262338957430697921446883
>>> f = factorint(a, limit=10000)
>>> f == {991: 1, int(202916782076162456022877024859): 1, 7: 1}
True
>>> isprime(max(f))
False
This number has a small factor and a residual perfect power whose
base is greater than the limit:
>>> factorint(3*101**7, limit=5)
{3: 1, 101: 7}
List of Factors:
If ``multiple`` is set to ``True`` then a list containing the
prime factors including multiplicities is returned.
>>> factorint(24, multiple=True)
[2, 2, 2, 3]
Visual Factorization:
If ``visual`` is set to ``True``, then it will return a visual
factorization of the integer. For example:
>>> from sympy import pprint
>>> pprint(factorint(4200, visual=True))
3 1 2 1
2 *3 *5 *7
Note that this is achieved by using the evaluate=False flag in Mul
and Pow. If you do other manipulations with an expression where
evaluate=False, it may evaluate. Therefore, you should use the
visual option only for visualization, and use the normal dictionary
returned by visual=False if you want to perform operations on the
factors.
You can easily switch between the two forms by sending them back to
factorint:
>>> from sympy import Mul
>>> regular = factorint(1764); regular
{2: 2, 3: 2, 7: 2}
>>> pprint(factorint(regular))
2 2 2
2 *3 *7
>>> visual = factorint(1764, visual=True); pprint(visual)
2 2 2
2 *3 *7
>>> print(factorint(visual))
{2: 2, 3: 2, 7: 2}
If you want to send a number to be factored in a partially factored form
you can do so with a dictionary or unevaluated expression:
>>> factorint(factorint({4: 2, 12: 3})) # twice to toggle to dict form
{2: 10, 3: 3}
>>> factorint(Mul(4, 12, evaluate=False))
{2: 4, 3: 1}
The table of the output logic is:
====== ====== ======= =======
Visual
------ ----------------------
Input True False other
====== ====== ======= =======
dict mul dict mul
n mul dict dict
mul mul dict dict
====== ====== ======= =======
Notes
=====
Algorithm:
The function switches between multiple algorithms. Trial division
quickly finds small factors (of the order 1-5 digits), and finds
all large factors if given enough time. The Pollard rho and p-1
algorithms are used to find large factors ahead of time; they
will often find factors of the order of 10 digits within a few
seconds:
>>> factors = factorint(12345678910111213141516)
>>> for base, exp in sorted(factors.items()):
... print('%s %s' % (base, exp))
...
2 2
2507191691 1
1231026625769 1
Any of these methods can optionally be disabled with the following
boolean parameters:
- ``use_trial``: Toggle use of trial division
- ``use_rho``: Toggle use of Pollard's rho method
- ``use_pm1``: Toggle use of Pollard's p-1 method
``factorint`` also periodically checks if the remaining part is
a prime number or a perfect power, and in those cases stops.
For unevaluated factorial, it uses Legendre's formula(theorem).
If ``verbose`` is set to ``True``, detailed progress is printed.
See Also
========
smoothness, smoothness_p, divisors
"""
if isinstance(n, Dict):
n = dict(n)
if multiple:
fac = factorint(n, limit=limit, use_trial=use_trial,
use_rho=use_rho, use_pm1=use_pm1,
verbose=verbose, visual=False, multiple=False)
factorlist = sum(([p] * fac[p] if fac[p] > 0 else [S.One/p]*(-fac[p])
for p in sorted(fac)), [])
return factorlist
factordict = {}
if visual and not isinstance(n, (Mul, dict)):
factordict = factorint(n, limit=limit, use_trial=use_trial,
use_rho=use_rho, use_pm1=use_pm1,
verbose=verbose, visual=False)
elif isinstance(n, Mul):
factordict = {int(k): int(v) for k, v in
n.as_powers_dict().items()}
elif isinstance(n, dict):
factordict = n
if factordict and isinstance(n, (Mul, dict)):
# check it
for key in list(factordict.keys()):
if isprime(key):
continue
e = factordict.pop(key)
d = factorint(key, limit=limit, use_trial=use_trial, use_rho=use_rho,
use_pm1=use_pm1, verbose=verbose, visual=False)
for k, v in d.items():
if k in factordict:
factordict[k] += v*e
else:
factordict[k] = v*e
if visual or (type(n) is dict and
visual is not True and
visual is not False):
if factordict == {}:
return S.One
if -1 in factordict:
factordict.pop(-1)
args = [S.NegativeOne]
else:
args = []
args.extend([Pow(*i, evaluate=False)
for i in sorted(factordict.items())])
return Mul(*args, evaluate=False)
elif isinstance(n, (dict, Mul)):
return factordict
assert use_trial or use_rho or use_pm1 or use_ecm
from sympy.functions.combinatorial.factorials import factorial
if isinstance(n, factorial):
x = as_int(n.args[0])
if x >= 20:
factors = {}
m = 2 # to initialize the if condition below
for p in sieve.primerange(2, x + 1):
if m > 1:
m, q = 0, x // p
while q != 0:
m += q
q //= p
factors[p] = m
if factors and verbose:
for k in sorted(factors):
print(factor_msg % (k, factors[k]))
if verbose:
print(complete_msg)
return factors
else:
# if n < 20!, direct computation is faster
# since it uses a lookup table
n = n.func(x)
n = as_int(n)
if limit:
limit = int(limit)
use_ecm = False
# special cases
if n < 0:
factors = factorint(
-n, limit=limit, use_trial=use_trial, use_rho=use_rho,
use_pm1=use_pm1, verbose=verbose, visual=False)
factors[-1] = 1
return factors
if limit and limit < 2:
if n == 1:
return {}
return {n: 1}
elif n < 10:
# doing this we are assured of getting a limit > 2
# when we have to compute it later
return [{0: 1}, {}, {2: 1}, {3: 1}, {2: 2}, {5: 1},
{2: 1, 3: 1}, {7: 1}, {2: 3}, {3: 2}][n]
factors = {}
# do simplistic factorization
if verbose:
sn = str(n)
if len(sn) > 50:
print('Factoring %s' % sn[:5] + \
'..(%i other digits)..' % (len(sn) - 10) + sn[-5:])
else:
print('Factoring', n)
# this is the preliminary factorization for small factors
# We want to guarantee that there are no small prime factors,
# so we run even if `use_trial` is False.
small = 2**15
fail_max = 600
small = min(small, limit or small)
if verbose:
print(trial_int_msg % (2, small, fail_max))
n, next_p = _factorint_small(factors, n, small, fail_max)
if factors and verbose:
for k in sorted(factors):
print(factor_msg % (k, factors[k]))
if next_p == 0:
if n > 1:
factors[int(n)] = 1
if verbose:
print(complete_msg)
return factors
# first check if the simplistic run didn't finish
# because of the limit and check for a perfect
# power before exiting
if limit and next_p > limit:
if verbose:
print('Exceeded limit:', limit)
if _check_termination(factors, n, limit, use_trial,
use_rho, use_pm1, verbose, next_p):
return factors
if n > 1:
factors[int(n)] = 1
return factors
if _check_termination(factors, n, limit, use_trial,
use_rho, use_pm1, verbose, next_p):
return factors
# continue with more advanced factorization methods
# ...do a Fermat test since it's so easy and we need the
# square root anyway. Finding 2 factors is easy if they are
# "close enough." This is the big root equivalent of dividing by
# 2, 3, 5.
sqrt_n = isqrt(n)
a = sqrt_n + 1
# If `n % 4 == 1`, `a` must be odd for `a**2 - n` to be a square number.
if (n % 4 == 1) ^ (a & 1):
a += 1
a2 = a**2
b2 = a2 - n
for _ in range(3):
b, fermat = sqrtrem(b2)
if not fermat:
if verbose:
print(fermat_msg)
for r in [a - b, a + b]:
facs = factorint(r, limit=limit, use_trial=use_trial,
use_rho=use_rho, use_pm1=use_pm1,
verbose=verbose)
for k, v in facs.items():
factors[k] = factors.get(k, 0) + v
if verbose:
print(complete_msg)
return factors
b2 += (a + 1) << 2 # equiv to (a + 2)**2 - n
a += 2
# these are the limits for trial division which will
# be attempted in parallel with pollard methods
low, high = next_p, 2*next_p
# add 1 to make sure limit is reached in primerange calls
_limit = (limit or sqrt_n) + 1
iteration = 0
while 1:
high_ = min(high, _limit)
# Trial division
if use_trial:
if verbose:
print(trial_msg % (low, high_))
ps = sieve.primerange(low, high_)
n, found_trial = _trial(factors, n, ps, verbose)
next_p = high_
if found_trial and _check_termination(factors, n, limit, use_trial,
use_rho, use_pm1, verbose, next_p):
return factors
else:
found_trial = False
if high > _limit:
if verbose:
print('Exceeded limit:', _limit)
if n > 1:
factors[int(n)] = 1
if verbose:
print(complete_msg)
return factors
# Only used advanced methods when no small factors were found
if not found_trial:
# Pollard p-1
if use_pm1:
if verbose:
print(pm1_msg % (low, high_))
c = pollard_pm1(n, B=low, seed=high_)
if c:
if c < next_p**2 or isprime(c):
ps = [c]
else:
ps = factorint(c, limit=limit,
use_trial=use_trial,
use_rho=use_rho,
use_pm1=use_pm1,
use_ecm=use_ecm,
verbose=verbose)
n, _ = _trial(factors, n, ps, verbose=False)
if _check_termination(factors, n, limit, use_trial,
use_rho, use_pm1, verbose, next_p):
return factors
# Pollard rho
if use_rho:
if verbose:
print(rho_msg % (1, low, high_))
c = pollard_rho(n, retries=1, max_steps=low, seed=high_)
if c:
if c < next_p**2 or isprime(c):
ps = [c]
else:
ps = factorint(c, limit=limit,
use_trial=use_trial,
use_rho=use_rho,
use_pm1=use_pm1,
use_ecm=use_ecm,
verbose=verbose)
n, _ = _trial(factors, n, ps, verbose=False)
if _check_termination(factors, n, limit, use_trial,
use_rho, use_pm1, verbose, next_p):
return factors
# Use subexponential algorithms if use_ecm
# Use pollard algorithms for finding small factors for 3 iterations
# if after small factors the number of digits of n >= 25 then use ecm
iteration += 1
if use_ecm and iteration >= 3 and num_digits(n) >= 24:
break
low, high = high, high*2
B1 = 10000
B2 = 100*B1
num_curves = 50
while(1):
if verbose:
print(ecm_msg % (B1, B2, num_curves))
factor = _ecm_one_factor(n, B1, B2, num_curves, seed=B1)
if factor:
if factor < next_p**2 or isprime(factor):
ps = [factor]
else:
ps = factorint(factor, limit=limit,
use_trial=use_trial,
use_rho=use_rho,
use_pm1=use_pm1,
use_ecm=use_ecm,
verbose=verbose)
n, _ = _trial(factors, n, ps, verbose=False)
if _check_termination(factors, n, limit, use_trial,
use_rho, use_pm1, verbose, next_p):
return factors
B1 *= 5
B2 = 100*B1
num_curves *= 4
def factorrat(rat, limit=None, use_trial=True, use_rho=True, use_pm1=True,
verbose=False, visual=None, multiple=False):
r"""
Given a Rational ``r``, ``factorrat(r)`` returns a dict containing
the prime factors of ``r`` as keys and their respective multiplicities
as values. For example:
>>> from sympy import factorrat, S
>>> factorrat(S(8)/9) # 8/9 = (2**3) * (3**-2)
{2: 3, 3: -2}
>>> factorrat(S(-1)/987) # -1/789 = -1 * (3**-1) * (7**-1) * (47**-1)
{-1: 1, 3: -1, 7: -1, 47: -1}
Please see the docstring for ``factorint`` for detailed explanations
and examples of the following keywords:
- ``limit``: Integer limit up to which trial division is done
- ``use_trial``: Toggle use of trial division
- ``use_rho``: Toggle use of Pollard's rho method
- ``use_pm1``: Toggle use of Pollard's p-1 method
- ``verbose``: Toggle detailed printing of progress
- ``multiple``: Toggle returning a list of factors or dict
- ``visual``: Toggle product form of output
"""
if multiple:
fac = factorrat(rat, limit=limit, use_trial=use_trial,
use_rho=use_rho, use_pm1=use_pm1,
verbose=verbose, visual=False, multiple=False)
factorlist = sum(([p] * fac[p] if fac[p] > 0 else [S.One/p]*(-fac[p])
for p, _ in sorted(fac.items(),
key=lambda elem: elem[0]
if elem[1] > 0
else 1/elem[0])), [])
return factorlist
f = factorint(rat.p, limit=limit, use_trial=use_trial,
use_rho=use_rho, use_pm1=use_pm1,
verbose=verbose).copy()
f = defaultdict(int, f)
for p, e in factorint(rat.q, limit=limit,
use_trial=use_trial,
use_rho=use_rho,
use_pm1=use_pm1,
verbose=verbose).items():
f[p] += -e
if len(f) > 1 and 1 in f:
del f[1]
if not visual:
return dict(f)
else:
if -1 in f:
f.pop(-1)
args = [S.NegativeOne]
else:
args = []
args.extend([Pow(*i, evaluate=False)
for i in sorted(f.items())])
return Mul(*args, evaluate=False)
def primefactors(n, limit=None, verbose=False, **kwargs):
"""Return a sorted list of n's prime factors, ignoring multiplicity
and any composite factor that remains if the limit was set too low
for complete factorization. Unlike factorint(), primefactors() does
not return -1 or 0.
Parameters
==========
n : integer
limit, verbose, **kwargs :
Additional keyword arguments to be passed to ``factorint``.
Since ``kwargs`` is new in version 1.13,
``limit`` and ``verbose`` are retained for compatibility purposes.
Returns
=======
list(int) : List of prime numbers dividing ``n``
Examples
========
>>> from sympy.ntheory import primefactors, factorint, isprime
>>> primefactors(6)
[2, 3]
>>> primefactors(-5)
[5]
>>> sorted(factorint(123456).items())
[(2, 6), (3, 1), (643, 1)]
>>> primefactors(123456)
[2, 3, 643]
>>> sorted(factorint(10000000001, limit=200).items())
[(101, 1), (99009901, 1)]
>>> isprime(99009901)
False
>>> primefactors(10000000001, limit=300)
[101]
See Also
========
factorint, divisors
"""
n = int(n)
kwargs.update({"visual": None, "multiple": False,
"limit": limit, "verbose": verbose})
factors = sorted(factorint(n=n, **kwargs).keys())
# We want to calculate
# s = [f for f in factors if isprime(f)]
s = [f for f in factors[:-1:] if f not in [-1, 0, 1]]
if factors and isprime(factors[-1]):
s += [factors[-1]]
return s
def _divisors(n, proper=False):
"""Helper function for divisors which generates the divisors.
Parameters
==========
n : int
a nonnegative integer
proper: bool
If `True`, returns the generator that outputs only the proper divisor (i.e., excluding n).
"""
if n <= 1:
if not proper and n:
yield 1
return
factordict = factorint(n)
ps = sorted(factordict.keys())
def rec_gen(n=0):
if n == len(ps):
yield 1
else:
pows = [1]
for _ in range(factordict[ps[n]]):
pows.append(pows[-1] * ps[n])
yield from (p * q for q in rec_gen(n + 1) for p in pows)
if proper:
yield from (p for p in rec_gen() if p != n)
else:
yield from rec_gen()
def divisors(n, generator=False, proper=False):
r"""
Return all divisors of n sorted from 1..n by default.
If generator is ``True`` an unordered generator is returned.
The number of divisors of n can be quite large if there are many
prime factors (counting repeated factors). If only the number of
factors is desired use divisor_count(n).
Examples
========
>>> from sympy import divisors, divisor_count
>>> divisors(24)
[1, 2, 3, 4, 6, 8, 12, 24]
>>> divisor_count(24)
8
>>> list(divisors(120, generator=True))
[1, 2, 4, 8, 3, 6, 12, 24, 5, 10, 20, 40, 15, 30, 60, 120]
Notes
=====
This is a slightly modified version of Tim Peters referenced at:
https://stackoverflow.com/questions/1010381/python-factorization
See Also
========
primefactors, factorint, divisor_count
"""
rv = _divisors(as_int(abs(n)), proper)
return rv if generator else sorted(rv)
def divisor_count(n, modulus=1, proper=False):
"""
Return the number of divisors of ``n``. If ``modulus`` is not 1 then only
those that are divisible by ``modulus`` are counted. If ``proper`` is True
then the divisor of ``n`` will not be counted.
Examples
========
>>> from sympy import divisor_count
>>> divisor_count(6)
4
>>> divisor_count(6, 2)
2
>>> divisor_count(6, proper=True)
3
See Also
========
factorint, divisors, totient, proper_divisor_count
"""
if not modulus:
return 0
elif modulus != 1:
n, r = divmod(n, modulus)
if r:
return 0
if n == 0:
return 0
n = Mul(*[v + 1 for k, v in factorint(n).items() if k > 1])
if n and proper:
n -= 1
return n
def proper_divisors(n, generator=False):
"""
Return all divisors of n except n, sorted by default.
If generator is ``True`` an unordered generator is returned.
Examples
========
>>> from sympy import proper_divisors, proper_divisor_count
>>> proper_divisors(24)
[1, 2, 3, 4, 6, 8, 12]
>>> proper_divisor_count(24)
7
>>> list(proper_divisors(120, generator=True))
[1, 2, 4, 8, 3, 6, 12, 24, 5, 10, 20, 40, 15, 30, 60]
See Also
========
factorint, divisors, proper_divisor_count
"""
return divisors(n, generator=generator, proper=True)
def proper_divisor_count(n, modulus=1):
"""
Return the number of proper divisors of ``n``.
Examples
========
>>> from sympy import proper_divisor_count
>>> proper_divisor_count(6)
3
>>> proper_divisor_count(6, modulus=2)
1
See Also
========
divisors, proper_divisors, divisor_count
"""
return divisor_count(n, modulus=modulus, proper=True)
def _udivisors(n):
"""Helper function for udivisors which generates the unitary divisors.
Parameters
==========
n : int
a nonnegative integer
"""
if n <= 1:
if n == 1:
yield 1
return
factorpows = [p**e for p, e in factorint(n).items()]
# We want to calculate
# yield from (math.prod(s) for s in powersets(factorpows))
for i in range(2**len(factorpows)):
d = 1
for k in range(i.bit_length()):
if i & 1:
d *= factorpows[k]
i >>= 1
yield d
def udivisors(n, generator=False):
r"""
Return all unitary divisors of n sorted from 1..n by default.
If generator is ``True`` an unordered generator is returned.
The number of unitary divisors of n can be quite large if there are many
prime factors. If only the number of unitary divisors is desired use
udivisor_count(n).
Examples
========
>>> from sympy.ntheory.factor_ import udivisors, udivisor_count
>>> udivisors(15)
[1, 3, 5, 15]
>>> udivisor_count(15)
4
>>> sorted(udivisors(120, generator=True))
[1, 3, 5, 8, 15, 24, 40, 120]
See Also
========
primefactors, factorint, divisors, divisor_count, udivisor_count
References
==========
.. [1] https://en.wikipedia.org/wiki/Unitary_divisor
.. [2] https://mathworld.wolfram.com/UnitaryDivisor.html
"""
rv = _udivisors(as_int(abs(n)))
return rv if generator else sorted(rv)
def udivisor_count(n):
"""
Return the number of unitary divisors of ``n``.
Parameters
==========
n : integer
Examples
========
>>> from sympy.ntheory.factor_ import udivisor_count
>>> udivisor_count(120)
8
See Also
========
factorint, divisors, udivisors, divisor_count, totient
References
==========
.. [1] https://mathworld.wolfram.com/UnitaryDivisorFunction.html
"""
if n == 0:
return 0
return 2**len([p for p in factorint(n) if p > 1])
def _antidivisors(n):
"""Helper function for antidivisors which generates the antidivisors.
Parameters
==========
n : int
a nonnegative integer
"""
if n <= 2:
return
for d in _divisors(n):
y = 2*d
if n > y and n % y:
yield y
for d in _divisors(2*n-1):
if n > d >= 2 and n % d:
yield d
for d in _divisors(2*n+1):
if n > d >= 2 and n % d:
yield d
def antidivisors(n, generator=False):
r"""
Return all antidivisors of n sorted from 1..n by default.
Antidivisors [1]_ of n are numbers that do not divide n by the largest
possible margin. If generator is True an unordered generator is returned.
Examples
========
>>> from sympy.ntheory.factor_ import antidivisors
>>> antidivisors(24)
[7, 16]
>>> sorted(antidivisors(128, generator=True))
[3, 5, 15, 17, 51, 85]
See Also
========
primefactors, factorint, divisors, divisor_count, antidivisor_count
References
==========
.. [1] definition is described in https://oeis.org/A066272/a066272a.html
"""
rv = _antidivisors(as_int(abs(n)))
return rv if generator else sorted(rv)
def antidivisor_count(n):
"""
Return the number of antidivisors [1]_ of ``n``.
Parameters
==========
n : integer
Examples
========
>>> from sympy.ntheory.factor_ import antidivisor_count
>>> antidivisor_count(13)
4
>>> antidivisor_count(27)
5
See Also
========
factorint, divisors, antidivisors, divisor_count, totient
References
==========
.. [1] formula from https://oeis.org/A066272
"""
n = as_int(abs(n))
if n <= 2:
return 0
return divisor_count(2*n - 1) + divisor_count(2*n + 1) + \
divisor_count(n) - divisor_count(n, 2) - 5
@deprecated("""\
The `sympy.ntheory.factor_.totient` has been moved to `sympy.functions.combinatorial.numbers.totient`.""",
deprecated_since_version="1.13",
active_deprecations_target='deprecated-ntheory-symbolic-functions')
def totient(n):
r"""
Calculate the Euler totient function phi(n)
.. deprecated:: 1.13
The ``totient`` function is deprecated. Use :class:`sympy.functions.combinatorial.numbers.totient`
instead. See its documentation for more information. See
:ref:`deprecated-ntheory-symbolic-functions` for details.
``totient(n)`` or `\phi(n)` is the number of positive integers `\leq` n
that are relatively prime to n.
Parameters
==========
n : integer
Examples
========
>>> from sympy.functions.combinatorial.numbers import totient
>>> totient(1)
1
>>> totient(25)
20
>>> totient(45) == totient(5)*totient(9)
True
See Also
========
divisor_count
References
==========
.. [1] https://en.wikipedia.org/wiki/Euler%27s_totient_function
.. [2] https://mathworld.wolfram.com/TotientFunction.html
"""
from sympy.functions.combinatorial.numbers import totient as _totient
return _totient(n)
@deprecated("""\
The `sympy.ntheory.factor_.reduced_totient` has been moved to `sympy.functions.combinatorial.numbers.reduced_totient`.""",
deprecated_since_version="1.13",
active_deprecations_target='deprecated-ntheory-symbolic-functions')
def reduced_totient(n):
r"""
Calculate the Carmichael reduced totient function lambda(n)
.. deprecated:: 1.13
The ``reduced_totient`` function is deprecated. Use :class:`sympy.functions.combinatorial.numbers.reduced_totient`
instead. See its documentation for more information. See
:ref:`deprecated-ntheory-symbolic-functions` for details.
``reduced_totient(n)`` or `\lambda(n)` is the smallest m > 0 such that
`k^m \equiv 1 \mod n` for all k relatively prime to n.
Examples
========
>>> from sympy.functions.combinatorial.numbers import reduced_totient
>>> reduced_totient(1)
1
>>> reduced_totient(8)
2
>>> reduced_totient(30)
4
See Also
========
totient
References
==========
.. [1] https://en.wikipedia.org/wiki/Carmichael_function
.. [2] https://mathworld.wolfram.com/CarmichaelFunction.html
"""
from sympy.functions.combinatorial.numbers import reduced_totient as _reduced_totient
return _reduced_totient(n)
@deprecated("""\
The `sympy.ntheory.factor_.divisor_sigma` has been moved to `sympy.functions.combinatorial.numbers.divisor_sigma`.""",
deprecated_since_version="1.13",
active_deprecations_target='deprecated-ntheory-symbolic-functions')
def divisor_sigma(n, k=1):
r"""
Calculate the divisor function `\sigma_k(n)` for positive integer n
.. deprecated:: 1.13
The ``divisor_sigma`` function is deprecated. Use :class:`sympy.functions.combinatorial.numbers.divisor_sigma`
instead. See its documentation for more information. See
:ref:`deprecated-ntheory-symbolic-functions` for details.
``divisor_sigma(n, k)`` is equal to ``sum([x**k for x in divisors(n)])``
If n's prime factorization is:
.. math ::
n = \prod_{i=1}^\omega p_i^{m_i},
then
.. math ::
\sigma_k(n) = \prod_{i=1}^\omega (1+p_i^k+p_i^{2k}+\cdots
+ p_i^{m_ik}).
Parameters
==========
n : integer
k : integer, optional
power of divisors in the sum
for k = 0, 1:
``divisor_sigma(n, 0)`` is equal to ``divisor_count(n)``
``divisor_sigma(n, 1)`` is equal to ``sum(divisors(n))``
Default for k is 1.
Examples
========
>>> from sympy.functions.combinatorial.numbers import divisor_sigma
>>> divisor_sigma(18, 0)
6
>>> divisor_sigma(39, 1)
56
>>> divisor_sigma(12, 2)
210
>>> divisor_sigma(37)
38
See Also
========
divisor_count, totient, divisors, factorint
References
==========
.. [1] https://en.wikipedia.org/wiki/Divisor_function
"""
from sympy.functions.combinatorial.numbers import divisor_sigma as func_divisor_sigma
return func_divisor_sigma(n, k)
def _divisor_sigma(n:int, k:int=1) -> int:
r""" Calculate the divisor function `\sigma_k(n)` for positive integer n
Parameters
==========
n : int
positive integer
k : int
nonnegative integer
See Also
========
sympy.functions.combinatorial.numbers.divisor_sigma
"""
if k == 0:
return math.prod(e + 1 for e in factorint(n).values())
return math.prod((p**(k*(e + 1)) - 1)//(p**k - 1) for p, e in factorint(n).items())
def core(n, t=2):
r"""
Calculate core(n, t) = `core_t(n)` of a positive integer n
``core_2(n)`` is equal to the squarefree part of n
If n's prime factorization is:
.. math ::
n = \prod_{i=1}^\omega p_i^{m_i},
then
.. math ::
core_t(n) = \prod_{i=1}^\omega p_i^{m_i \mod t}.
Parameters
==========
n : integer
t : integer
core(n, t) calculates the t-th power free part of n
``core(n, 2)`` is the squarefree part of ``n``
``core(n, 3)`` is the cubefree part of ``n``
Default for t is 2.
Examples
========
>>> from sympy.ntheory.factor_ import core
>>> core(24, 2)
6
>>> core(9424, 3)
1178
>>> core(379238)
379238
>>> core(15**11, 10)
15
See Also
========
factorint, sympy.solvers.diophantine.diophantine.square_factor
References
==========
.. [1] https://en.wikipedia.org/wiki/Square-free_integer#Squarefree_core
"""
n = as_int(n)
t = as_int(t)
if n <= 0:
raise ValueError("n must be a positive integer")
elif t <= 1:
raise ValueError("t must be >= 2")
else:
y = 1
for p, e in factorint(n).items():
y *= p**(e % t)
return y
@deprecated("""\
The `sympy.ntheory.factor_.udivisor_sigma` has been moved to `sympy.functions.combinatorial.numbers.udivisor_sigma`.""",
deprecated_since_version="1.13",
active_deprecations_target='deprecated-ntheory-symbolic-functions')
def udivisor_sigma(n, k=1):
r"""
Calculate the unitary divisor function `\sigma_k^*(n)` for positive integer n
.. deprecated:: 1.13
The ``udivisor_sigma`` function is deprecated. Use :class:`sympy.functions.combinatorial.numbers.udivisor_sigma`
instead. See its documentation for more information. See
:ref:`deprecated-ntheory-symbolic-functions` for details.
``udivisor_sigma(n, k)`` is equal to ``sum([x**k for x in udivisors(n)])``
If n's prime factorization is:
.. math ::
n = \prod_{i=1}^\omega p_i^{m_i},
then
.. math ::
\sigma_k^*(n) = \prod_{i=1}^\omega (1+ p_i^{m_ik}).
Parameters
==========
k : power of divisors in the sum
for k = 0, 1:
``udivisor_sigma(n, 0)`` is equal to ``udivisor_count(n)``
``udivisor_sigma(n, 1)`` is equal to ``sum(udivisors(n))``
Default for k is 1.
Examples
========
>>> from sympy.functions.combinatorial.numbers import udivisor_sigma
>>> udivisor_sigma(18, 0)
4
>>> udivisor_sigma(74, 1)
114
>>> udivisor_sigma(36, 3)
47450
>>> udivisor_sigma(111)
152
See Also
========
divisor_count, totient, divisors, udivisors, udivisor_count, divisor_sigma,
factorint
References
==========
.. [1] https://mathworld.wolfram.com/UnitaryDivisorFunction.html
"""
from sympy.functions.combinatorial.numbers import udivisor_sigma as _udivisor_sigma
return _udivisor_sigma(n, k)
@deprecated("""\
The `sympy.ntheory.factor_.primenu` has been moved to `sympy.functions.combinatorial.numbers.primenu`.""",
deprecated_since_version="1.13",
active_deprecations_target='deprecated-ntheory-symbolic-functions')
def primenu(n):
r"""
Calculate the number of distinct prime factors for a positive integer n.
.. deprecated:: 1.13
The ``primenu`` function is deprecated. Use :class:`sympy.functions.combinatorial.numbers.primenu`
instead. See its documentation for more information. See
:ref:`deprecated-ntheory-symbolic-functions` for details.
If n's prime factorization is:
.. math ::
n = \prod_{i=1}^k p_i^{m_i},
then ``primenu(n)`` or `\nu(n)` is:
.. math ::
\nu(n) = k.
Examples
========
>>> from sympy.functions.combinatorial.numbers import primenu
>>> primenu(1)
0
>>> primenu(30)
3
See Also
========
factorint
References
==========
.. [1] https://mathworld.wolfram.com/PrimeFactor.html
"""
from sympy.functions.combinatorial.numbers import primenu as _primenu
return _primenu(n)
@deprecated("""\
The `sympy.ntheory.factor_.primeomega` has been moved to `sympy.functions.combinatorial.numbers.primeomega`.""",
deprecated_since_version="1.13",
active_deprecations_target='deprecated-ntheory-symbolic-functions')
def primeomega(n):
r"""
Calculate the number of prime factors counting multiplicities for a
positive integer n.
.. deprecated:: 1.13
The ``primeomega`` function is deprecated. Use :class:`sympy.functions.combinatorial.numbers.primeomega`
instead. See its documentation for more information. See
:ref:`deprecated-ntheory-symbolic-functions` for details.
If n's prime factorization is:
.. math ::
n = \prod_{i=1}^k p_i^{m_i},
then ``primeomega(n)`` or `\Omega(n)` is:
.. math ::
\Omega(n) = \sum_{i=1}^k m_i.
Examples
========
>>> from sympy.functions.combinatorial.numbers import primeomega
>>> primeomega(1)
0
>>> primeomega(20)
3
See Also
========
factorint
References
==========
.. [1] https://mathworld.wolfram.com/PrimeFactor.html
"""
from sympy.functions.combinatorial.numbers import primeomega as _primeomega
return _primeomega(n)
def mersenne_prime_exponent(nth):
"""Returns the exponent ``i`` for the nth Mersenne prime (which
has the form `2^i - 1`).
Examples
========
>>> from sympy.ntheory.factor_ import mersenne_prime_exponent
>>> mersenne_prime_exponent(1)
2
>>> mersenne_prime_exponent(20)
4423
"""
n = as_int(nth)
if n < 1:
raise ValueError("nth must be a positive integer; mersenne_prime_exponent(1) == 2")
if n > 51:
raise ValueError("There are only 51 perfect numbers; nth must be less than or equal to 51")
return MERSENNE_PRIME_EXPONENTS[n - 1]
def is_perfect(n):
"""Returns True if ``n`` is a perfect number, else False.
A perfect number is equal to the sum of its positive, proper divisors.
Examples
========
>>> from sympy.functions.combinatorial.numbers import divisor_sigma
>>> from sympy.ntheory.factor_ import is_perfect, divisors
>>> is_perfect(20)
False
>>> is_perfect(6)
True
>>> 6 == divisor_sigma(6) - 6 == sum(divisors(6)[:-1])
True
References
==========
.. [1] https://mathworld.wolfram.com/PerfectNumber.html
.. [2] https://en.wikipedia.org/wiki/Perfect_number
"""
n = as_int(n)
if n < 1:
return False
if n % 2 == 0:
m = (n.bit_length() + 1) >> 1
if (1 << (m - 1)) * ((1 << m) - 1) != n:
# Even perfect numbers must be of the form `2^{m-1}(2^m-1)`
return False
return m in MERSENNE_PRIME_EXPONENTS or is_mersenne_prime(2**m - 1)
# n is an odd integer
if n < 10**2000: # https://www.lirmm.fr/~ochem/opn/
return False
if n % 105 == 0: # not divis by 105
return False
if all(n % m != r for m, r in [(12, 1), (468, 117), (324, 81)]):
return False
# there are many criteria that the factor structure of n
# must meet; since we will have to factor it to test the
# structure we will have the factors and can then check
# to see whether it is a perfect number or not. So we
# skip the structure checks and go straight to the final
# test below.
result = abundance(n) == 0
if result:
raise ValueError(filldedent('''In 1888, Sylvester stated: "
...a prolonged meditation on the subject has satisfied
me that the existence of any one such [odd perfect number]
-- its escape, so to say, from the complex web of conditions
which hem it in on all sides -- would be little short of a
miracle." I guess SymPy just found that miracle and it
factors like this: %s''' % factorint(n)))
return result
def abundance(n):
"""Returns the difference between the sum of the positive
proper divisors of a number and the number.
Examples
========
>>> from sympy.ntheory import abundance, is_perfect, is_abundant
>>> abundance(6)
0
>>> is_perfect(6)
True
>>> abundance(10)
-2
>>> is_abundant(10)
False
"""
return _divisor_sigma(n) - 2 * n
def is_abundant(n):
"""Returns True if ``n`` is an abundant number, else False.
A abundant number is smaller than the sum of its positive proper divisors.
Examples
========
>>> from sympy.ntheory.factor_ import is_abundant
>>> is_abundant(20)
True
>>> is_abundant(15)
False
References
==========
.. [1] https://mathworld.wolfram.com/AbundantNumber.html
"""
n = as_int(n)
if is_perfect(n):
return False
return n % 6 == 0 or bool(abundance(n) > 0)
def is_deficient(n):
"""Returns True if ``n`` is a deficient number, else False.
A deficient number is greater than the sum of its positive proper divisors.
Examples
========
>>> from sympy.ntheory.factor_ import is_deficient
>>> is_deficient(20)
False
>>> is_deficient(15)
True
References
==========
.. [1] https://mathworld.wolfram.com/DeficientNumber.html
"""
n = as_int(n)
if is_perfect(n):
return False
return bool(abundance(n) < 0)
def is_amicable(m, n):
"""Returns True if the numbers `m` and `n` are "amicable", else False.
Amicable numbers are two different numbers so related that the sum
of the proper divisors of each is equal to that of the other.
Examples
========
>>> from sympy.functions.combinatorial.numbers import divisor_sigma
>>> from sympy.ntheory.factor_ import is_amicable
>>> is_amicable(220, 284)
True
>>> divisor_sigma(220) == divisor_sigma(284)
True
References
==========
.. [1] https://en.wikipedia.org/wiki/Amicable_numbers
"""
return m != n and m + n == _divisor_sigma(m) == _divisor_sigma(n)
def is_carmichael(n):
""" Returns True if the numbers `n` is Carmichael number, else False.
Parameters
==========
n : Integer
References
==========
.. [1] https://en.wikipedia.org/wiki/Carmichael_number
.. [2] https://oeis.org/A002997
"""
if n < 561:
return False
return n % 2 and not isprime(n) and \
all(e == 1 and (n - 1) % (p - 1) == 0 for p, e in factorint(n).items())
def find_carmichael_numbers_in_range(x, y):
""" Returns a list of the number of Carmichael in the range
See Also
========
is_carmichael
"""
if 0 <= x <= y:
if x % 2 == 0:
return [i for i in range(x + 1, y, 2) if is_carmichael(i)]
else:
return [i for i in range(x, y, 2) if is_carmichael(i)]
else:
raise ValueError('The provided range is not valid. x and y must be non-negative integers and x <= y')
def find_first_n_carmichaels(n):
""" Returns the first n Carmichael numbers.
Parameters
==========
n : Integer
See Also
========
is_carmichael
"""
i = 561
carmichaels = []
while len(carmichaels) < n:
if is_carmichael(i):
carmichaels.append(i)
i += 2
return carmichaels
def dra(n, b):
"""
Returns the additive digital root of a natural number ``n`` in base ``b``
which is a single digit value obtained by an iterative process of summing
digits, on each iteration using the result from the previous iteration to
compute a digit sum.
Examples
========
>>> from sympy.ntheory.factor_ import dra
>>> dra(3110, 12)
8
References
==========
.. [1] https://en.wikipedia.org/wiki/Digital_root
"""
num = abs(as_int(n))
b = as_int(b)
if b <= 1:
raise ValueError("Base should be an integer greater than 1")
if num == 0:
return 0
return (1 + (num - 1) % (b - 1))
def drm(n, b):
"""
Returns the multiplicative digital root of a natural number ``n`` in a given
base ``b`` which is a single digit value obtained by an iterative process of
multiplying digits, on each iteration using the result from the previous
iteration to compute the digit multiplication.
Examples
========
>>> from sympy.ntheory.factor_ import drm
>>> drm(9876, 10)
0
>>> drm(49, 10)
8
References
==========
.. [1] https://mathworld.wolfram.com/MultiplicativeDigitalRoot.html
"""
n = abs(as_int(n))
b = as_int(b)
if b <= 1:
raise ValueError("Base should be an integer greater than 1")
while n > b:
mul = 1
while n > 1:
n, r = divmod(n, b)
if r == 0:
return 0
mul *= r
n = mul
return n
PK ]ZZZD+]R�� �� sympy/ntheory/generate.py"""
Generating and counting primes.
"""
from bisect import bisect, bisect_left
from itertools import count
# Using arrays for sieving instead of lists greatly reduces
# memory consumption
from array import array as _array
from sympy.core.random import randint
from sympy.external.gmpy import sqrt
from .primetest import isprime
from sympy.utilities.decorator import deprecated
from sympy.utilities.misc import as_int
def _as_int_ceiling(a):
""" Wrapping ceiling in as_int will raise an error if there was a problem
determining whether the expression was exactly an integer or not."""
from sympy.functions.elementary.integers import ceiling
return as_int(ceiling(a))
class Sieve:
"""A list of prime numbers, implemented as a dynamically
growing sieve of Eratosthenes. When a lookup is requested involving
an odd number that has not been sieved, the sieve is automatically
extended up to that number. Implementation details limit the number of
primes to ``2^32-1``.
Examples
========
>>> from sympy import sieve
>>> sieve._reset() # this line for doctest only
>>> 25 in sieve
False
>>> sieve._list
array('L', [2, 3, 5, 7, 11, 13, 17, 19, 23])
"""
# data shared (and updated) by all Sieve instances
def __init__(self, sieve_interval=1_000_000):
""" Initial parameters for the Sieve class.
Parameters
==========
sieve_interval (int): Amount of memory to be used
Raises
======
ValueError
If ``sieve_interval`` is not positive.
"""
self._n = 6
self._list = _array('L', [2, 3, 5, 7, 11, 13]) # primes
self._tlist = _array('L', [0, 1, 1, 2, 2, 4]) # totient
self._mlist = _array('i', [0, 1, -1, -1, 0, -1]) # mobius
if sieve_interval <= 0:
raise ValueError("sieve_interval should be a positive integer")
self.sieve_interval = sieve_interval
assert all(len(i) == self._n for i in (self._list, self._tlist, self._mlist))
def __repr__(self):
return ("<%s sieve (%i): %i, %i, %i, ... %i, %i\n"
"%s sieve (%i): %i, %i, %i, ... %i, %i\n"
"%s sieve (%i): %i, %i, %i, ... %i, %i>") % (
'prime', len(self._list),
self._list[0], self._list[1], self._list[2],
self._list[-2], self._list[-1],
'totient', len(self._tlist),
self._tlist[0], self._tlist[1],
self._tlist[2], self._tlist[-2], self._tlist[-1],
'mobius', len(self._mlist),
self._mlist[0], self._mlist[1],
self._mlist[2], self._mlist[-2], self._mlist[-1])
def _reset(self, prime=None, totient=None, mobius=None):
"""Reset all caches (default). To reset one or more set the
desired keyword to True."""
if all(i is None for i in (prime, totient, mobius)):
prime = totient = mobius = True
if prime:
self._list = self._list[:self._n]
if totient:
self._tlist = self._tlist[:self._n]
if mobius:
self._mlist = self._mlist[:self._n]
def extend(self, n):
"""Grow the sieve to cover all primes <= n.
Examples
========
>>> from sympy import sieve
>>> sieve._reset() # this line for doctest only
>>> sieve.extend(30)
>>> sieve[10] == 29
True
"""
n = int(n)
# `num` is even at any point in the function.
# This satisfies the condition required by `self._primerange`.
num = self._list[-1] + 1
if n < num:
return
num2 = num**2
while num2 <= n:
self._list += _array('L', self._primerange(num, num2))
num, num2 = num2, num2**2
# Merge the sieves
self._list += _array('L', self._primerange(num, n + 1))
def _primerange(self, a, b):
""" Generate all prime numbers in the range (a, b).
Parameters
==========
a, b : positive integers assuming the following conditions
* a is an even number
* 2 < self._list[-1] < a < b < nextprime(self._list[-1])**2
Yields
======
p (int): prime numbers such that ``a < p < b``
Examples
========
>>> from sympy.ntheory.generate import Sieve
>>> s = Sieve()
>>> s._list[-1]
13
>>> list(s._primerange(18, 31))
[19, 23, 29]
"""
if b % 2:
b -= 1
while a < b:
block_size = min(self.sieve_interval, (b - a) // 2)
# Create the list such that block[x] iff (a + 2x + 1) is prime.
# Note that even numbers are not considered here.
block = [True] * block_size
for p in self._list[1:bisect(self._list, sqrt(a + 2 * block_size + 1))]:
for t in range((-(a + 1 + p) // 2) % p, block_size, p):
block[t] = False
for idx, p in enumerate(block):
if p:
yield a + 2 * idx + 1
a += 2 * block_size
def extend_to_no(self, i):
"""Extend to include the ith prime number.
Parameters
==========
i : integer
Examples
========
>>> from sympy import sieve
>>> sieve._reset() # this line for doctest only
>>> sieve.extend_to_no(9)
>>> sieve._list
array('L', [2, 3, 5, 7, 11, 13, 17, 19, 23])
Notes
=====
The list is extended by 50% if it is too short, so it is
likely that it will be longer than requested.
"""
i = as_int(i)
while len(self._list) < i:
self.extend(int(self._list[-1] * 1.5))
def primerange(self, a, b=None):
"""Generate all prime numbers in the range [2, a) or [a, b).
Examples
========
>>> from sympy import sieve, prime
All primes less than 19:
>>> print([i for i in sieve.primerange(19)])
[2, 3, 5, 7, 11, 13, 17]
All primes greater than or equal to 7 and less than 19:
>>> print([i for i in sieve.primerange(7, 19)])
[7, 11, 13, 17]
All primes through the 10th prime
>>> list(sieve.primerange(prime(10) + 1))
[2, 3, 5, 7, 11, 13, 17, 19, 23, 29]
"""
if b is None:
b = _as_int_ceiling(a)
a = 2
else:
a = max(2, _as_int_ceiling(a))
b = _as_int_ceiling(b)
if a >= b:
return
self.extend(b)
yield from self._list[bisect_left(self._list, a):
bisect_left(self._list, b)]
def totientrange(self, a, b):
"""Generate all totient numbers for the range [a, b).
Examples
========
>>> from sympy import sieve
>>> print([i for i in sieve.totientrange(7, 18)])
[6, 4, 6, 4, 10, 4, 12, 6, 8, 8, 16]
"""
a = max(1, _as_int_ceiling(a))
b = _as_int_ceiling(b)
n = len(self._tlist)
if a >= b:
return
elif b <= n:
for i in range(a, b):
yield self._tlist[i]
else:
self._tlist += _array('L', range(n, b))
for i in range(1, n):
ti = self._tlist[i]
if ti == i - 1:
startindex = (n + i - 1) // i * i
for j in range(startindex, b, i):
self._tlist[j] -= self._tlist[j] // i
if i >= a:
yield ti
for i in range(n, b):
ti = self._tlist[i]
if ti == i:
for j in range(i, b, i):
self._tlist[j] -= self._tlist[j] // i
if i >= a:
yield self._tlist[i]
def mobiusrange(self, a, b):
"""Generate all mobius numbers for the range [a, b).
Parameters
==========
a : integer
First number in range
b : integer
First number outside of range
Examples
========
>>> from sympy import sieve
>>> print([i for i in sieve.mobiusrange(7, 18)])
[-1, 0, 0, 1, -1, 0, -1, 1, 1, 0, -1]
"""
a = max(1, _as_int_ceiling(a))
b = _as_int_ceiling(b)
n = len(self._mlist)
if a >= b:
return
elif b <= n:
for i in range(a, b):
yield self._mlist[i]
else:
self._mlist += _array('i', [0]*(b - n))
for i in range(1, n):
mi = self._mlist[i]
startindex = (n + i - 1) // i * i
for j in range(startindex, b, i):
self._mlist[j] -= mi
if i >= a:
yield mi
for i in range(n, b):
mi = self._mlist[i]
for j in range(2 * i, b, i):
self._mlist[j] -= mi
if i >= a:
yield mi
def search(self, n):
"""Return the indices i, j of the primes that bound n.
If n is prime then i == j.
Although n can be an expression, if ceiling cannot convert
it to an integer then an n error will be raised.
Examples
========
>>> from sympy import sieve
>>> sieve.search(25)
(9, 10)
>>> sieve.search(23)
(9, 9)
"""
test = _as_int_ceiling(n)
n = as_int(n)
if n < 2:
raise ValueError("n should be >= 2 but got: %s" % n)
if n > self._list[-1]:
self.extend(n)
b = bisect(self._list, n)
if self._list[b - 1] == test:
return b, b
else:
return b, b + 1
def __contains__(self, n):
try:
n = as_int(n)
assert n >= 2
except (ValueError, AssertionError):
return False
if n % 2 == 0:
return n == 2
a, b = self.search(n)
return a == b
def __iter__(self):
for n in count(1):
yield self[n]
def __getitem__(self, n):
"""Return the nth prime number"""
if isinstance(n, slice):
self.extend_to_no(n.stop)
# Python 2.7 slices have 0 instead of None for start, so
# we can't default to 1.
start = n.start if n.start is not None else 0
if start < 1:
# sieve[:5] would be empty (starting at -1), let's
# just be explicit and raise.
raise IndexError("Sieve indices start at 1.")
return self._list[start - 1:n.stop - 1:n.step]
else:
if n < 1:
# offset is one, so forbid explicit access to sieve[0]
# (would surprisingly return the last one).
raise IndexError("Sieve indices start at 1.")
n = as_int(n)
self.extend_to_no(n)
return self._list[n - 1]
# Generate a global object for repeated use in trial division etc
sieve = Sieve()
def prime(nth):
r""" Return the nth prime, with the primes indexed as prime(1) = 2,
prime(2) = 3, etc.... The nth prime is approximately $n\log(n)$.
Logarithmic integral of $x$ is a pretty nice approximation for number of
primes $\le x$, i.e.
li(x) ~ pi(x)
In fact, for the numbers we are concerned about( x<1e11 ),
li(x) - pi(x) < 50000
Also,
li(x) > pi(x) can be safely assumed for the numbers which
can be evaluated by this function.
Here, we find the least integer m such that li(m) > n using binary search.
Now pi(m-1) < li(m-1) <= n,
We find pi(m - 1) using primepi function.
Starting from m, we have to find n - pi(m-1) more primes.
For the inputs this implementation can handle, we will have to test
primality for at max about 10**5 numbers, to get our answer.
Examples
========
>>> from sympy import prime
>>> prime(10)
29
>>> prime(1)
2
>>> prime(100000)
1299709
See Also
========
sympy.ntheory.primetest.isprime : Test if n is prime
primerange : Generate all primes in a given range
primepi : Return the number of primes less than or equal to n
References
==========
.. [1] https://en.wikipedia.org/wiki/Prime_number_theorem#Table_of_.CF.80.28x.29.2C_x_.2F_log_x.2C_and_li.28x.29
.. [2] https://en.wikipedia.org/wiki/Prime_number_theorem#Approximations_for_the_nth_prime_number
.. [3] https://en.wikipedia.org/wiki/Skewes%27_number
"""
n = as_int(nth)
if n < 1:
raise ValueError("nth must be a positive integer; prime(1) == 2")
if n <= len(sieve._list):
return sieve[n]
from sympy.functions.elementary.exponential import log
from sympy.functions.special.error_functions import li
a = 2 # Lower bound for binary search
# leave n inside int since int(i*r) != i*int(r) is not a valid property
# e.g. int(2*.5) != 2*int(.5)
b = int(n*(log(n) + log(log(n)))) # Upper bound for the search.
while a < b:
mid = (a + b) >> 1
if li(mid) > n:
b = mid
else:
a = mid + 1
n_primes = _primepi(a - 1)
while n_primes < n:
if isprime(a):
n_primes += 1
a += 1
return a - 1
@deprecated("""\
The `sympy.ntheory.generate.primepi` has been moved to `sympy.functions.combinatorial.numbers.primepi`.""",
deprecated_since_version="1.13",
active_deprecations_target='deprecated-ntheory-symbolic-functions')
def primepi(n):
r""" Represents the prime counting function pi(n) = the number
of prime numbers less than or equal to n.
.. deprecated:: 1.13
The ``primepi`` function is deprecated. Use :class:`sympy.functions.combinatorial.numbers.primepi`
instead. See its documentation for more information. See
:ref:`deprecated-ntheory-symbolic-functions` for details.
Algorithm Description:
In sieve method, we remove all multiples of prime p
except p itself.
Let phi(i,j) be the number of integers 2 <= k <= i
which remain after sieving from primes less than
or equal to j.
Clearly, pi(n) = phi(n, sqrt(n))
If j is not a prime,
phi(i,j) = phi(i, j - 1)
if j is a prime,
We remove all numbers(except j) whose
smallest prime factor is j.
Let $x= j \times a$ be such a number, where $2 \le a \le i / j$
Now, after sieving from primes $\le j - 1$,
a must remain
(because x, and hence a has no prime factor $\le j - 1$)
Clearly, there are phi(i / j, j - 1) such a
which remain on sieving from primes $\le j - 1$
Now, if a is a prime less than equal to j - 1,
$x= j \times a$ has smallest prime factor = a, and
has already been removed(by sieving from a).
So, we do not need to remove it again.
(Note: there will be pi(j - 1) such x)
Thus, number of x, that will be removed are:
phi(i / j, j - 1) - phi(j - 1, j - 1)
(Note that pi(j - 1) = phi(j - 1, j - 1))
$\Rightarrow$ phi(i,j) = phi(i, j - 1) - phi(i / j, j - 1) + phi(j - 1, j - 1)
So,following recursion is used and implemented as dp:
phi(a, b) = phi(a, b - 1), if b is not a prime
phi(a, b) = phi(a, b-1)-phi(a / b, b-1) + phi(b-1, b-1), if b is prime
Clearly a is always of the form floor(n / k),
which can take at most $2\sqrt{n}$ values.
Two arrays arr1,arr2 are maintained
arr1[i] = phi(i, j),
arr2[i] = phi(n // i, j)
Finally the answer is arr2[1]
Examples
========
>>> from sympy import primepi, prime, prevprime, isprime
>>> primepi(25)
9
So there are 9 primes less than or equal to 25. Is 25 prime?
>>> isprime(25)
False
It is not. So the first prime less than 25 must be the
9th prime:
>>> prevprime(25) == prime(9)
True
See Also
========
sympy.ntheory.primetest.isprime : Test if n is prime
primerange : Generate all primes in a given range
prime : Return the nth prime
"""
from sympy.functions.combinatorial.numbers import primepi as func_primepi
return func_primepi(n)
def _primepi(n:int) -> int:
r""" Represents the prime counting function pi(n) = the number
of prime numbers less than or equal to n.
Explanation
===========
In sieve method, we remove all multiples of prime p
except p itself.
Let phi(i,j) be the number of integers 2 <= k <= i
which remain after sieving from primes less than
or equal to j.
Clearly, pi(n) = phi(n, sqrt(n))
If j is not a prime,
phi(i,j) = phi(i, j - 1)
if j is a prime,
We remove all numbers(except j) whose
smallest prime factor is j.
Let $x= j \times a$ be such a number, where $2 \le a \le i / j$
Now, after sieving from primes $\le j - 1$,
a must remain
(because x, and hence a has no prime factor $\le j - 1$)
Clearly, there are phi(i / j, j - 1) such a
which remain on sieving from primes $\le j - 1$
Now, if a is a prime less than equal to j - 1,
$x= j \times a$ has smallest prime factor = a, and
has already been removed(by sieving from a).
So, we do not need to remove it again.
(Note: there will be pi(j - 1) such x)
Thus, number of x, that will be removed are:
phi(i / j, j - 1) - phi(j - 1, j - 1)
(Note that pi(j - 1) = phi(j - 1, j - 1))
$\Rightarrow$ phi(i,j) = phi(i, j - 1) - phi(i / j, j - 1) + phi(j - 1, j - 1)
So,following recursion is used and implemented as dp:
phi(a, b) = phi(a, b - 1), if b is not a prime
phi(a, b) = phi(a, b-1)-phi(a / b, b-1) + phi(b-1, b-1), if b is prime
Clearly a is always of the form floor(n / k),
which can take at most $2\sqrt{n}$ values.
Two arrays arr1,arr2 are maintained
arr1[i] = phi(i, j),
arr2[i] = phi(n // i, j)
Finally the answer is arr2[1]
Parameters
==========
n : int
"""
if n < 2:
return 0
if n <= sieve._list[-1]:
return sieve.search(n)[0]
lim = sqrt(n)
arr1 = [0] * (lim + 1)
arr2 = [0] * (lim + 1)
for i in range(1, lim + 1):
arr1[i] = i - 1
arr2[i] = n // i - 1
for i in range(2, lim + 1):
# Presently, arr1[k]=phi(k,i - 1),
# arr2[k] = phi(n // k,i - 1)
if arr1[i] == arr1[i - 1]:
continue
p = arr1[i - 1]
for j in range(1, min(n // (i * i), lim) + 1):
st = i * j
if st <= lim:
arr2[j] -= arr2[st] - p
else:
arr2[j] -= arr1[n // st] - p
lim2 = min(lim, i * i - 1)
for j in range(lim, lim2, -1):
arr1[j] -= arr1[j // i] - p
return arr2[1]
def nextprime(n, ith=1):
""" Return the ith prime greater than n.
Parameters
==========
n : integer
ith : positive integer
Returns
=======
int : Return the ith prime greater than n
Raises
======
ValueError
If ``ith <= 0``.
If ``n`` or ``ith`` is not an integer.
Notes
=====
Potential primes are located at 6*j +/- 1. This
property is used during searching.
>>> from sympy import nextprime
>>> [(i, nextprime(i)) for i in range(10, 15)]
[(10, 11), (11, 13), (12, 13), (13, 17), (14, 17)]
>>> nextprime(2, ith=2) # the 2nd prime after 2
5
See Also
========
prevprime : Return the largest prime smaller than n
primerange : Generate all primes in a given range
"""
n = int(n)
i = as_int(ith)
if i <= 0:
raise ValueError("ith should be positive")
if n < 2:
n = 2
i -= 1
if n <= sieve._list[-2]:
l, _ = sieve.search(n)
if l + i - 1 < len(sieve._list):
return sieve._list[l + i - 1]
return nextprime(sieve._list[-1], l + i - len(sieve._list))
if 1 < i:
for _ in range(i):
n = nextprime(n)
return n
nn = 6*(n//6)
if nn == n:
n += 1
if isprime(n):
return n
n += 4
elif n - nn == 5:
n += 2
if isprime(n):
return n
n += 4
else:
n = nn + 5
while 1:
if isprime(n):
return n
n += 2
if isprime(n):
return n
n += 4
def prevprime(n):
""" Return the largest prime smaller than n.
Notes
=====
Potential primes are located at 6*j +/- 1. This
property is used during searching.
>>> from sympy import prevprime
>>> [(i, prevprime(i)) for i in range(10, 15)]
[(10, 7), (11, 7), (12, 11), (13, 11), (14, 13)]
See Also
========
nextprime : Return the ith prime greater than n
primerange : Generates all primes in a given range
"""
n = _as_int_ceiling(n)
if n < 3:
raise ValueError("no preceding primes")
if n < 8:
return {3: 2, 4: 3, 5: 3, 6: 5, 7: 5}[n]
if n <= sieve._list[-1]:
l, u = sieve.search(n)
if l == u:
return sieve[l-1]
else:
return sieve[l]
nn = 6*(n//6)
if n - nn <= 1:
n = nn - 1
if isprime(n):
return n
n -= 4
else:
n = nn + 1
while 1:
if isprime(n):
return n
n -= 2
if isprime(n):
return n
n -= 4
def primerange(a, b=None):
""" Generate a list of all prime numbers in the range [2, a),
or [a, b).
If the range exists in the default sieve, the values will
be returned from there; otherwise values will be returned
but will not modify the sieve.
Examples
========
>>> from sympy import primerange, prime
All primes less than 19:
>>> list(primerange(19))
[2, 3, 5, 7, 11, 13, 17]
All primes greater than or equal to 7 and less than 19:
>>> list(primerange(7, 19))
[7, 11, 13, 17]
All primes through the 10th prime
>>> list(primerange(prime(10) + 1))
[2, 3, 5, 7, 11, 13, 17, 19, 23, 29]
The Sieve method, primerange, is generally faster but it will
occupy more memory as the sieve stores values. The default
instance of Sieve, named sieve, can be used:
>>> from sympy import sieve
>>> list(sieve.primerange(1, 30))
[2, 3, 5, 7, 11, 13, 17, 19, 23, 29]
Notes
=====
Some famous conjectures about the occurrence of primes in a given
range are [1]:
- Twin primes: though often not, the following will give 2 primes
an infinite number of times:
primerange(6*n - 1, 6*n + 2)
- Legendre's: the following always yields at least one prime
primerange(n**2, (n+1)**2+1)
- Bertrand's (proven): there is always a prime in the range
primerange(n, 2*n)
- Brocard's: there are at least four primes in the range
primerange(prime(n)**2, prime(n+1)**2)
The average gap between primes is log(n) [2]; the gap between
primes can be arbitrarily large since sequences of composite
numbers are arbitrarily large, e.g. the numbers in the sequence
n! + 2, n! + 3 ... n! + n are all composite.
See Also
========
prime : Return the nth prime
nextprime : Return the ith prime greater than n
prevprime : Return the largest prime smaller than n
randprime : Returns a random prime in a given range
primorial : Returns the product of primes based on condition
Sieve.primerange : return range from already computed primes
or extend the sieve to contain the requested
range.
References
==========
.. [1] https://en.wikipedia.org/wiki/Prime_number
.. [2] https://primes.utm.edu/notes/gaps.html
"""
if b is None:
a, b = 2, a
if a >= b:
return
# If we already have the range, return it.
largest_known_prime = sieve._list[-1]
if b <= largest_known_prime:
yield from sieve.primerange(a, b)
return
# If we know some of it, return it.
if a <= largest_known_prime:
yield from sieve._list[bisect_left(sieve._list, a):]
a = largest_known_prime + 1
elif a % 2:
a -= 1
tail = min(b, (largest_known_prime)**2)
if a < tail:
yield from sieve._primerange(a, tail)
a = tail
if b <= a:
return
# otherwise compute, without storing, the desired range.
while 1:
a = nextprime(a)
if a < b:
yield a
else:
return
def randprime(a, b):
""" Return a random prime number in the range [a, b).
Bertrand's postulate assures that
randprime(a, 2*a) will always succeed for a > 1.
Note that due to implementation difficulties,
the prime numbers chosen are not uniformly random.
For example, there are two primes in the range [112, 128),
``113`` and ``127``, but ``randprime(112, 128)`` returns ``127``
with a probability of 15/17.
Examples
========
>>> from sympy import randprime, isprime
>>> randprime(1, 30) #doctest: +SKIP
13
>>> isprime(randprime(1, 30))
True
See Also
========
primerange : Generate all primes in a given range
References
==========
.. [1] https://en.wikipedia.org/wiki/Bertrand's_postulate
"""
if a >= b:
return
a, b = map(int, (a, b))
n = randint(a - 1, b)
p = nextprime(n)
if p >= b:
p = prevprime(b)
if p < a:
raise ValueError("no primes exist in the specified range")
return p
def primorial(n, nth=True):
"""
Returns the product of the first n primes (default) or
the primes less than or equal to n (when ``nth=False``).
Examples
========
>>> from sympy.ntheory.generate import primorial, primerange
>>> from sympy import factorint, Mul, primefactors, sqrt
>>> primorial(4) # the first 4 primes are 2, 3, 5, 7
210
>>> primorial(4, nth=False) # primes <= 4 are 2 and 3
6
>>> primorial(1)
2
>>> primorial(1, nth=False)
1
>>> primorial(sqrt(101), nth=False)
210
One can argue that the primes are infinite since if you take
a set of primes and multiply them together (e.g. the primorial) and
then add or subtract 1, the result cannot be divided by any of the
original factors, hence either 1 or more new primes must divide this
product of primes.
In this case, the number itself is a new prime:
>>> factorint(primorial(4) + 1)
{211: 1}
In this case two new primes are the factors:
>>> factorint(primorial(4) - 1)
{11: 1, 19: 1}
Here, some primes smaller and larger than the primes multiplied together
are obtained:
>>> p = list(primerange(10, 20))
>>> sorted(set(primefactors(Mul(*p) + 1)).difference(set(p)))
[2, 5, 31, 149]
See Also
========
primerange : Generate all primes in a given range
"""
if nth:
n = as_int(n)
else:
n = int(n)
if n < 1:
raise ValueError("primorial argument must be >= 1")
p = 1
if nth:
for i in range(1, n + 1):
p *= prime(i)
else:
for i in primerange(2, n + 1):
p *= i
return p
def cycle_length(f, x0, nmax=None, values=False):
"""For a given iterated sequence, return a generator that gives
the length of the iterated cycle (lambda) and the length of terms
before the cycle begins (mu); if ``values`` is True then the
terms of the sequence will be returned instead. The sequence is
started with value ``x0``.
Note: more than the first lambda + mu terms may be returned and this
is the cost of cycle detection with Brent's method; there are, however,
generally less terms calculated than would have been calculated if the
proper ending point were determined, e.g. by using Floyd's method.
>>> from sympy.ntheory.generate import cycle_length
This will yield successive values of i <-- func(i):
>>> def gen(func, i):
... while 1:
... yield i
... i = func(i)
...
A function is defined:
>>> func = lambda i: (i**2 + 1) % 51
and given a seed of 4 and the mu and lambda terms calculated:
>>> next(cycle_length(func, 4))
(6, 3)
We can see what is meant by looking at the output:
>>> iter = cycle_length(func, 4, values=True)
>>> list(iter)
[4, 17, 35, 2, 5, 26, 14, 44, 50, 2, 5, 26, 14]
There are 6 repeating values after the first 3.
If a sequence is suspected of being longer than you might wish, ``nmax``
can be used to exit early (and mu will be returned as None):
>>> next(cycle_length(func, 4, nmax = 4))
(4, None)
>>> list(cycle_length(func, 4, nmax = 4, values=True))
[4, 17, 35, 2]
Code modified from:
https://en.wikipedia.org/wiki/Cycle_detection.
"""
nmax = int(nmax or 0)
# main phase: search successive powers of two
power = lam = 1
tortoise, hare = x0, f(x0) # f(x0) is the element/node next to x0.
i = 1
if values:
yield tortoise
while tortoise != hare and (not nmax or i < nmax):
i += 1
if power == lam: # time to start a new power of two?
tortoise = hare
power *= 2
lam = 0
if values:
yield hare
hare = f(hare)
lam += 1
if nmax and i == nmax:
if values:
return
else:
yield nmax, None
return
if not values:
# Find the position of the first repetition of length lambda
mu = 0
tortoise = hare = x0
for i in range(lam):
hare = f(hare)
while tortoise != hare:
tortoise = f(tortoise)
hare = f(hare)
mu += 1
yield lam, mu
def composite(nth):
""" Return the nth composite number, with the composite numbers indexed as
composite(1) = 4, composite(2) = 6, etc....
Examples
========
>>> from sympy import composite
>>> composite(36)
52
>>> composite(1)
4
>>> composite(17737)
20000
See Also
========
sympy.ntheory.primetest.isprime : Test if n is prime
primerange : Generate all primes in a given range
primepi : Return the number of primes less than or equal to n
prime : Return the nth prime
compositepi : Return the number of positive composite numbers less than or equal to n
"""
n = as_int(nth)
if n < 1:
raise ValueError("nth must be a positive integer; composite(1) == 4")
composite_arr = [4, 6, 8, 9, 10, 12, 14, 15, 16, 18]
if n <= 10:
return composite_arr[n - 1]
a, b = 4, sieve._list[-1]
if n <= b - _primepi(b) - 1:
while a < b - 1:
mid = (a + b) >> 1
if mid - _primepi(mid) - 1 > n:
b = mid
else:
a = mid
if isprime(a):
a -= 1
return a
from sympy.functions.elementary.exponential import log
from sympy.functions.special.error_functions import li
a = 4 # Lower bound for binary search
b = int(n*(log(n) + log(log(n)))) # Upper bound for the search.
while a < b:
mid = (a + b) >> 1
if mid - li(mid) - 1 > n:
b = mid
else:
a = mid + 1
n_composites = a - _primepi(a) - 1
while n_composites > n:
if not isprime(a):
n_composites -= 1
a -= 1
if isprime(a):
a -= 1
return a
def compositepi(n):
""" Return the number of positive composite numbers less than or equal to n.
The first positive composite is 4, i.e. compositepi(4) = 1.
Examples
========
>>> from sympy import compositepi
>>> compositepi(25)
15
>>> compositepi(1000)
831
See Also
========
sympy.ntheory.primetest.isprime : Test if n is prime
primerange : Generate all primes in a given range
prime : Return the nth prime
primepi : Return the number of primes less than or equal to n
composite : Return the nth composite number
"""
n = int(n)
if n < 4:
return 0
return n - _primepi(n) - 1
PK ]ZZZ�6�l! ! sympy/ntheory/modular.pyfrom math import prod
from sympy.external.gmpy import gcd, gcdext
from sympy.ntheory.primetest import isprime
from sympy.polys.domains import ZZ
from sympy.polys.galoistools import gf_crt, gf_crt1, gf_crt2
from sympy.utilities.misc import as_int
def symmetric_residue(a, m):
"""Return the residual mod m such that it is within half of the modulus.
>>> from sympy.ntheory.modular import symmetric_residue
>>> symmetric_residue(1, 6)
1
>>> symmetric_residue(4, 6)
-2
"""
if a <= m // 2:
return a
return a - m
def crt(m, v, symmetric=False, check=True):
r"""Chinese Remainder Theorem.
The moduli in m are assumed to be pairwise coprime. The output
is then an integer f, such that f = v_i mod m_i for each pair out
of v and m. If ``symmetric`` is False a positive integer will be
returned, else \|f\| will be less than or equal to the LCM of the
moduli, and thus f may be negative.
If the moduli are not co-prime the correct result will be returned
if/when the test of the result is found to be incorrect. This result
will be None if there is no solution.
The keyword ``check`` can be set to False if it is known that the moduli
are coprime.
Examples
========
As an example consider a set of residues ``U = [49, 76, 65]``
and a set of moduli ``M = [99, 97, 95]``. Then we have::
>>> from sympy.ntheory.modular import crt
>>> crt([99, 97, 95], [49, 76, 65])
(639985, 912285)
This is the correct result because::
>>> [639985 % m for m in [99, 97, 95]]
[49, 76, 65]
If the moduli are not co-prime, you may receive an incorrect result
if you use ``check=False``:
>>> crt([12, 6, 17], [3, 4, 2], check=False)
(954, 1224)
>>> [954 % m for m in [12, 6, 17]]
[6, 0, 2]
>>> crt([12, 6, 17], [3, 4, 2]) is None
True
>>> crt([3, 6], [2, 5])
(5, 6)
Note: the order of gf_crt's arguments is reversed relative to crt,
and that solve_congruence takes residue, modulus pairs.
Programmer's note: rather than checking that all pairs of moduli share
no GCD (an O(n**2) test) and rather than factoring all moduli and seeing
that there is no factor in common, a check that the result gives the
indicated residuals is performed -- an O(n) operation.
See Also
========
solve_congruence
sympy.polys.galoistools.gf_crt : low level crt routine used by this routine
"""
if check:
m = list(map(as_int, m))
v = list(map(as_int, v))
result = gf_crt(v, m, ZZ)
mm = prod(m)
if check:
if not all(v % m == result % m for v, m in zip(v, m)):
result = solve_congruence(*list(zip(v, m)),
check=False, symmetric=symmetric)
if result is None:
return result
result, mm = result
if symmetric:
return int(symmetric_residue(result, mm)), int(mm)
return int(result), int(mm)
def crt1(m):
"""First part of Chinese Remainder Theorem, for multiple application.
Examples
========
>>> from sympy.ntheory.modular import crt, crt1, crt2
>>> m = [99, 97, 95]
>>> v = [49, 76, 65]
The following two codes have the same result.
>>> crt(m, v)
(639985, 912285)
>>> mm, e, s = crt1(m)
>>> crt2(m, v, mm, e, s)
(639985, 912285)
However, it is faster when we want to fix ``m`` and
compute for multiple ``v``, i.e. the following cases:
>>> mm, e, s = crt1(m)
>>> vs = [[52, 21, 37], [19, 46, 76]]
>>> for v in vs:
... print(crt2(m, v, mm, e, s))
(397042, 912285)
(803206, 912285)
See Also
========
sympy.polys.galoistools.gf_crt1 : low level crt routine used by this routine
sympy.ntheory.modular.crt
sympy.ntheory.modular.crt2
"""
return gf_crt1(m, ZZ)
def crt2(m, v, mm, e, s, symmetric=False):
"""Second part of Chinese Remainder Theorem, for multiple application.
See ``crt1`` for usage.
Examples
========
>>> from sympy.ntheory.modular import crt1, crt2
>>> mm, e, s = crt1([18, 42, 6])
>>> crt2([18, 42, 6], [0, 0, 0], mm, e, s)
(0, 4536)
See Also
========
sympy.polys.galoistools.gf_crt2 : low level crt routine used by this routine
sympy.ntheory.modular.crt
sympy.ntheory.modular.crt1
"""
result = gf_crt2(v, m, mm, e, s, ZZ)
if symmetric:
return int(symmetric_residue(result, mm)), int(mm)
return int(result), int(mm)
def solve_congruence(*remainder_modulus_pairs, **hint):
"""Compute the integer ``n`` that has the residual ``ai`` when it is
divided by ``mi`` where the ``ai`` and ``mi`` are given as pairs to
this function: ((a1, m1), (a2, m2), ...). If there is no solution,
return None. Otherwise return ``n`` and its modulus.
The ``mi`` values need not be co-prime. If it is known that the moduli are
not co-prime then the hint ``check`` can be set to False (default=True) and
the check for a quicker solution via crt() (valid when the moduli are
co-prime) will be skipped.
If the hint ``symmetric`` is True (default is False), the value of ``n``
will be within 1/2 of the modulus, possibly negative.
Examples
========
>>> from sympy.ntheory.modular import solve_congruence
What number is 2 mod 3, 3 mod 5 and 2 mod 7?
>>> solve_congruence((2, 3), (3, 5), (2, 7))
(23, 105)
>>> [23 % m for m in [3, 5, 7]]
[2, 3, 2]
If you prefer to work with all remainder in one list and
all moduli in another, send the arguments like this:
>>> solve_congruence(*zip((2, 3, 2), (3, 5, 7)))
(23, 105)
The moduli need not be co-prime; in this case there may or
may not be a solution:
>>> solve_congruence((2, 3), (4, 6)) is None
True
>>> solve_congruence((2, 3), (5, 6))
(5, 6)
The symmetric flag will make the result be within 1/2 of the modulus:
>>> solve_congruence((2, 3), (5, 6), symmetric=True)
(-1, 6)
See Also
========
crt : high level routine implementing the Chinese Remainder Theorem
"""
def combine(c1, c2):
"""Return the tuple (a, m) which satisfies the requirement
that n = a + i*m satisfy n = a1 + j*m1 and n = a2 = k*m2.
References
==========
.. [1] https://en.wikipedia.org/wiki/Method_of_successive_substitution
"""
a1, m1 = c1
a2, m2 = c2
a, b, c = m1, a2 - a1, m2
g = gcd(a, b, c)
a, b, c = [i//g for i in [a, b, c]]
if a != 1:
g, inv_a, _ = gcdext(a, c)
if g != 1:
return None
b *= inv_a
a, m = a1 + m1*b, m1*c
return a, m
rm = remainder_modulus_pairs
symmetric = hint.get('symmetric', False)
if hint.get('check', True):
rm = [(as_int(r), as_int(m)) for r, m in rm]
# ignore redundant pairs but raise an error otherwise; also
# make sure that a unique set of bases is sent to gf_crt if
# they are all prime.
#
# The routine will work out less-trivial violations and
# return None, e.g. for the pairs (1,3) and (14,42) there
# is no answer because 14 mod 42 (having a gcd of 14) implies
# (14/2) mod (42/2), (14/7) mod (42/7) and (14/14) mod (42/14)
# which, being 0 mod 3, is inconsistent with 1 mod 3. But to
# preprocess the input beyond checking of another pair with 42
# or 3 as the modulus (for this example) is not necessary.
uniq = {}
for r, m in rm:
r %= m
if m in uniq:
if r != uniq[m]:
return None
continue
uniq[m] = r
rm = [(r, m) for m, r in uniq.items()]
del uniq
# if the moduli are co-prime, the crt will be significantly faster;
# checking all pairs for being co-prime gets to be slow but a prime
# test is a good trade-off
if all(isprime(m) for r, m in rm):
r, m = list(zip(*rm))
return crt(m, r, symmetric=symmetric, check=False)
rv = (0, 1)
for rmi in rm:
rv = combine(rv, rmi)
if rv is None:
break
n, m = rv
n = n % m
else:
if symmetric:
return symmetric_residue(n, m), m
return n, m
PK ]ZZZEU�~� � sympy/ntheory/multinomial.pyfrom sympy.utilities.misc import as_int
def binomial_coefficients(n):
"""Return a dictionary containing pairs :math:`{(k1,k2) : C_kn}` where
:math:`C_kn` are binomial coefficients and :math:`n=k1+k2`.
Examples
========
>>> from sympy.ntheory import binomial_coefficients
>>> binomial_coefficients(9)
{(0, 9): 1, (1, 8): 9, (2, 7): 36, (3, 6): 84,
(4, 5): 126, (5, 4): 126, (6, 3): 84, (7, 2): 36, (8, 1): 9, (9, 0): 1}
See Also
========
binomial_coefficients_list, multinomial_coefficients
"""
n = as_int(n)
d = {(0, n): 1, (n, 0): 1}
a = 1
for k in range(1, n//2 + 1):
a = (a * (n - k + 1))//k
d[k, n - k] = d[n - k, k] = a
return d
def binomial_coefficients_list(n):
""" Return a list of binomial coefficients as rows of the Pascal's
triangle.
Examples
========
>>> from sympy.ntheory import binomial_coefficients_list
>>> binomial_coefficients_list(9)
[1, 9, 36, 84, 126, 126, 84, 36, 9, 1]
See Also
========
binomial_coefficients, multinomial_coefficients
"""
n = as_int(n)
d = [1] * (n + 1)
a = 1
for k in range(1, n//2 + 1):
a = (a * (n - k + 1))//k
d[k] = d[n - k] = a
return d
def multinomial_coefficients(m, n):
r"""Return a dictionary containing pairs ``{(k1,k2,..,km) : C_kn}``
where ``C_kn`` are multinomial coefficients such that
``n=k1+k2+..+km``.
Examples
========
>>> from sympy.ntheory import multinomial_coefficients
>>> multinomial_coefficients(2, 5) # indirect doctest
{(0, 5): 1, (1, 4): 5, (2, 3): 10, (3, 2): 10, (4, 1): 5, (5, 0): 1}
Notes
=====
The algorithm is based on the following result:
.. math::
\binom{n}{k_1, \ldots, k_m} =
\frac{k_1 + 1}{n - k_1} \sum_{i=2}^m \binom{n}{k_1 + 1, \ldots, k_i - 1, \ldots}
Code contributed to Sage by Yann Laigle-Chapuy, copied with permission
of the author.
See Also
========
binomial_coefficients_list, binomial_coefficients
"""
m = as_int(m)
n = as_int(n)
if not m:
if n:
return {}
return {(): 1}
if m == 2:
return binomial_coefficients(n)
if m >= 2*n and n > 1:
return dict(multinomial_coefficients_iterator(m, n))
t = [n] + [0] * (m - 1)
r = {tuple(t): 1}
if n:
j = 0 # j will be the leftmost nonzero position
else:
j = m
# enumerate tuples in co-lex order
while j < m - 1:
# compute next tuple
tj = t[j]
if j:
t[j] = 0
t[0] = tj
if tj > 1:
t[j + 1] += 1
j = 0
start = 1
v = 0
else:
j += 1
start = j + 1
v = r[tuple(t)]
t[j] += 1
# compute the value
# NB: the initialization of v was done above
for k in range(start, m):
if t[k]:
t[k] -= 1
v += r[tuple(t)]
t[k] += 1
t[0] -= 1
r[tuple(t)] = (v * tj) // (n - t[0])
return r
def multinomial_coefficients_iterator(m, n, _tuple=tuple):
"""multinomial coefficient iterator
This routine has been optimized for `m` large with respect to `n` by taking
advantage of the fact that when the monomial tuples `t` are stripped of
zeros, their coefficient is the same as that of the monomial tuples from
``multinomial_coefficients(n, n)``. Therefore, the latter coefficients are
precomputed to save memory and time.
>>> from sympy.ntheory.multinomial import multinomial_coefficients
>>> m53, m33 = multinomial_coefficients(5,3), multinomial_coefficients(3,3)
>>> m53[(0,0,0,1,2)] == m53[(0,0,1,0,2)] == m53[(1,0,2,0,0)] == m33[(0,1,2)]
True
Examples
========
>>> from sympy.ntheory.multinomial import multinomial_coefficients_iterator
>>> it = multinomial_coefficients_iterator(20,3)
>>> next(it)
((3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0), 1)
"""
m = as_int(m)
n = as_int(n)
if m < 2*n or n == 1:
mc = multinomial_coefficients(m, n)
yield from mc.items()
else:
mc = multinomial_coefficients(n, n)
mc1 = {}
for k, v in mc.items():
mc1[_tuple(filter(None, k))] = v
mc = mc1
t = [n] + [0] * (m - 1)
t1 = _tuple(t)
b = _tuple(filter(None, t1))
yield (t1, mc[b])
if n:
j = 0 # j will be the leftmost nonzero position
else:
j = m
# enumerate tuples in co-lex order
while j < m - 1:
# compute next tuple
tj = t[j]
if j:
t[j] = 0
t[0] = tj
if tj > 1:
t[j + 1] += 1
j = 0
else:
j += 1
t[j] += 1
t[0] -= 1
t1 = _tuple(t)
b = _tuple(filter(None, t1))
yield (t1, mc[b])
PK ]ZZZĨk 5# 5# sympy/ntheory/partitions_.pyfrom mpmath.libmp import (fzero, from_int, from_rational,
fone, fhalf, bitcount, to_int, mpf_mul, mpf_div, mpf_sub,
mpf_add, mpf_sqrt, mpf_pi, mpf_cosh_sinh, mpf_cos, mpf_sin)
from sympy.external.gmpy import gcd, legendre, jacobi
from .residue_ntheory import _sqrt_mod_prime_power, is_quad_residue
from sympy.utilities.decorator import deprecated
from sympy.utilities.memoization import recurrence_memo
import math
from itertools import count
def _pre():
maxn = 10**5
global _factor
global _totient
_factor = [0]*maxn
_totient = [1]*maxn
lim = int(maxn**0.5) + 5
for i in range(2, lim):
if _factor[i] == 0:
for j in range(i*i, maxn, i):
if _factor[j] == 0:
_factor[j] = i
for i in range(2, maxn):
if _factor[i] == 0:
_factor[i] = i
_totient[i] = i-1
continue
x = _factor[i]
y = i//x
if y % x == 0:
_totient[i] = _totient[y]*x
else:
_totient[i] = _totient[y]*(x - 1)
def _a(n, k, prec):
""" Compute the inner sum in HRR formula [1]_
References
==========
.. [1] https://msp.org/pjm/1956/6-1/pjm-v6-n1-p18-p.pdf
"""
if k == 1:
return fone
k1 = k
e = 0
p = _factor[k]
while k1 % p == 0:
k1 //= p
e += 1
k2 = k//k1 # k2 = p^e
v = 1 - 24*n
pi = mpf_pi(prec)
if k1 == 1:
# k = p^e
if p == 2:
mod = 8*k
v = mod + v % mod
v = (v*pow(9, k - 1, mod)) % mod
m = _sqrt_mod_prime_power(v, 2, e + 3)[0]
arg = mpf_div(mpf_mul(
from_int(4*m), pi, prec), from_int(mod), prec)
return mpf_mul(mpf_mul(
from_int((-1)**e*jacobi(m - 1, m)),
mpf_sqrt(from_int(k), prec), prec),
mpf_sin(arg, prec), prec)
if p == 3:
mod = 3*k
v = mod + v % mod
if e > 1:
v = (v*pow(64, k//3 - 1, mod)) % mod
m = _sqrt_mod_prime_power(v, 3, e + 1)[0]
arg = mpf_div(mpf_mul(from_int(4*m), pi, prec),
from_int(mod), prec)
return mpf_mul(mpf_mul(
from_int(2*(-1)**(e + 1)*legendre(m, 3)),
mpf_sqrt(from_int(k//3), prec), prec),
mpf_sin(arg, prec), prec)
v = k + v % k
if v % p == 0:
if e == 1:
return mpf_mul(
from_int(jacobi(3, k)),
mpf_sqrt(from_int(k), prec), prec)
return fzero
if not is_quad_residue(v, p):
return fzero
_phi = p**(e - 1)*(p - 1)
v = (v*pow(576, _phi - 1, k))
m = _sqrt_mod_prime_power(v, p, e)[0]
arg = mpf_div(
mpf_mul(from_int(4*m), pi, prec),
from_int(k), prec)
return mpf_mul(mpf_mul(
from_int(2*jacobi(3, k)),
mpf_sqrt(from_int(k), prec), prec),
mpf_cos(arg, prec), prec)
if p != 2 or e >= 3:
d1, d2 = gcd(k1, 24), gcd(k2, 24)
e = 24//(d1*d2)
n1 = ((d2*e*n + (k2**2 - 1)//d1)*
pow(e*k2*k2*d2, _totient[k1] - 1, k1)) % k1
n2 = ((d1*e*n + (k1**2 - 1)//d2)*
pow(e*k1*k1*d1, _totient[k2] - 1, k2)) % k2
return mpf_mul(_a(n1, k1, prec), _a(n2, k2, prec), prec)
if e == 2:
n1 = ((8*n + 5)*pow(128, _totient[k1] - 1, k1)) % k1
n2 = (4 + ((n - 2 - (k1**2 - 1)//8)*(k1**2)) % 4) % 4
return mpf_mul(mpf_mul(
from_int(-1),
_a(n1, k1, prec), prec),
_a(n2, k2, prec))
n1 = ((8*n + 1)*pow(32, _totient[k1] - 1, k1)) % k1
n2 = (2 + (n - (k1**2 - 1)//8) % 2) % 2
return mpf_mul(_a(n1, k1, prec), _a(n2, k2, prec), prec)
def _d(n, j, prec, sq23pi, sqrt8):
"""
Compute the sinh term in the outer sum of the HRR formula.
The constants sqrt(2/3*pi) and sqrt(8) must be precomputed.
"""
j = from_int(j)
pi = mpf_pi(prec)
a = mpf_div(sq23pi, j, prec)
b = mpf_sub(from_int(n), from_rational(1, 24, prec), prec)
c = mpf_sqrt(b, prec)
ch, sh = mpf_cosh_sinh(mpf_mul(a, c), prec)
D = mpf_div(
mpf_sqrt(j, prec),
mpf_mul(mpf_mul(sqrt8, b), pi), prec)
E = mpf_sub(mpf_mul(a, ch), mpf_div(sh, c, prec), prec)
return mpf_mul(D, E)
@recurrence_memo([1, 1])
def _partition_rec(n: int, prev) -> int:
""" Calculate the partition function P(n)
Parameters
==========
n : int
nonnegative integer
"""
v = 0
penta = 0 # pentagonal number: 1, 5, 12, ...
for i in count():
penta += 3*i + 1
np = n - penta
if np < 0:
break
s = prev[np]
np -= i + 1
# np = n - gp where gp = generalized pentagonal: 2, 7, 15, ...
if 0 <= np:
s += prev[np]
v += -s if i % 2 else s
return v
def _partition(n: int) -> int:
""" Calculate the partition function P(n)
Parameters
==========
n : int
"""
if n < 0:
return 0
if (n <= 200_000 and n - _partition_rec.cache_length() < 70 or
_partition_rec.cache_length() == 2 and n < 14_400):
# There will be 2*10**5 elements created here
# and n elements created by partition, so in case we
# are going to be working with small n, we just
# use partition to calculate (and cache) the values
# since lookup is used there while summation, using
# _factor and _totient, will be used below. But we
# only do so if n is relatively close to the length
# of the cache since doing 1 calculation here is about
# the same as adding 70 elements to the cache. In addition,
# the startup here costs about the same as calculating the first
# 14,400 values via partition, so we delay startup here unless n
# is smaller than that.
return _partition_rec(n)
if '_factor' not in globals():
_pre()
# Estimate number of bits in p(n). This formula could be tidied
pbits = int((
math.pi*(2*n/3.)**0.5 -
math.log(4*n))/math.log(10) + 1) * \
math.log2(10)
prec = p = int(pbits*1.1 + 100)
# find the number of terms needed so rounded sum will be accurate
# using Rademacher's bound M(n, N) for the remainder after a partial
# sum of N terms (https://arxiv.org/pdf/1205.5991.pdf, (1.8))
c1 = 44*math.pi**2/(225*math.sqrt(3))
c2 = math.pi*math.sqrt(2)/75
c3 = math.pi*math.sqrt(2/3)
def _M(n, N):
sqrt = math.sqrt
return c1/sqrt(N) + c2*sqrt(N/(n - 1))*math.sinh(c3*sqrt(n)/N)
big = max(9, math.ceil(n**0.5)) # should be too large (for n > 65, ceil should work)
assert _M(n, big) < 0.5 # else double big until too large
while big > 40 and _M(n, big) < 0.5:
big //= 2
small = big
big = small*2
while big - small > 1:
N = (big + small)//2
if (er := _M(n, N)) < 0.5:
big = N
elif er >= 0.5:
small = N
M = big # done with function M; now have value
# sanity check for expected size of answer
if M > 10**5: # i.e. M > maxn
raise ValueError("Input too big") # i.e. n > 149832547102
# calculate it
s = fzero
sq23pi = mpf_mul(mpf_sqrt(from_rational(2, 3, p), p), mpf_pi(p), p)
sqrt8 = mpf_sqrt(from_int(8), p)
for q in range(1, M):
a = _a(n, q, p)
d = _d(n, q, p, sq23pi, sqrt8)
s = mpf_add(s, mpf_mul(a, d), prec)
# On average, the terms decrease rapidly in magnitude.
# Dynamically reducing the precision greatly improves
# performance.
p = bitcount(abs(to_int(d))) + 50
return int(to_int(mpf_add(s, fhalf, prec)))
@deprecated("""\
The `sympy.ntheory.partitions_.npartitions` has been moved to `sympy.functions.combinatorial.numbers.partition`.""",
deprecated_since_version="1.13",
active_deprecations_target='deprecated-ntheory-symbolic-functions')
def npartitions(n, verbose=False):
"""
Calculate the partition function P(n), i.e. the number of ways that
n can be written as a sum of positive integers.
.. deprecated:: 1.13
The ``npartitions`` function is deprecated. Use :class:`sympy.functions.combinatorial.numbers.partition`
instead. See its documentation for more information. See
:ref:`deprecated-ntheory-symbolic-functions` for details.
P(n) is computed using the Hardy-Ramanujan-Rademacher formula [1]_.
The correctness of this implementation has been tested through $10^{10}$.
Examples
========
>>> from sympy.functions.combinatorial.numbers import partition
>>> partition(25)
1958
References
==========
.. [1] https://mathworld.wolfram.com/PartitionFunctionP.html
"""
from sympy.functions.combinatorial.numbers import partition as func_partition
return func_partition(n)
PK ]ZZZ"�$9Z 9Z sympy/ntheory/primetest.py"""
Primality testing
"""
from itertools import count
from sympy.core.sympify import sympify
from sympy.external.gmpy import (gmpy as _gmpy, gcd, jacobi,
is_square as gmpy_is_square,
bit_scan1, is_fermat_prp, is_euler_prp,
is_selfridge_prp, is_strong_selfridge_prp,
is_strong_bpsw_prp)
from sympy.external.ntheory import _lucas_sequence
from sympy.utilities.misc import as_int, filldedent
# Note: This list should be updated whenever new Mersenne primes are found.
# Refer: https://www.mersenne.org/
MERSENNE_PRIME_EXPONENTS = (2, 3, 5, 7, 13, 17, 19, 31, 61, 89, 107, 127, 521, 607, 1279, 2203,
2281, 3217, 4253, 4423, 9689, 9941, 11213, 19937, 21701, 23209, 44497, 86243, 110503, 132049,
216091, 756839, 859433, 1257787, 1398269, 2976221, 3021377, 6972593, 13466917, 20996011, 24036583,
25964951, 30402457, 32582657, 37156667, 42643801, 43112609, 57885161, 74207281, 77232917, 82589933)
def is_fermat_pseudoprime(n, a):
r"""Returns True if ``n`` is prime or is an odd composite integer that
is coprime to ``a`` and satisfy the modular arithmetic congruence relation:
.. math ::
a^{n-1} \equiv 1 \pmod{n}
(where mod refers to the modulo operation).
Parameters
==========
n : Integer
``n`` is a positive integer.
a : Integer
``a`` is a positive integer.
``a`` and ``n`` should be relatively prime.
Returns
=======
bool : If ``n`` is prime, it always returns ``True``.
The composite number that returns ``True`` is called an Fermat pseudoprime.
Examples
========
>>> from sympy.ntheory.primetest import is_fermat_pseudoprime
>>> from sympy.ntheory.factor_ import isprime
>>> for n in range(1, 1000):
... if is_fermat_pseudoprime(n, 2) and not isprime(n):
... print(n)
341
561
645
References
==========
.. [1] https://en.wikipedia.org/wiki/Fermat_pseudoprime
"""
n, a = as_int(n), as_int(a)
if a == 1:
return n == 2 or bool(n % 2)
return is_fermat_prp(n, a)
def is_euler_pseudoprime(n, a):
r"""Returns True if ``n`` is prime or is an odd composite integer that
is coprime to ``a`` and satisfy the modular arithmetic congruence relation:
.. math ::
a^{(n-1)/2} \equiv \pm 1 \pmod{n}
(where mod refers to the modulo operation).
Parameters
==========
n : Integer
``n`` is a positive integer.
a : Integer
``a`` is a positive integer.
``a`` and ``n`` should be relatively prime.
Returns
=======
bool : If ``n`` is prime, it always returns ``True``.
The composite number that returns ``True`` is called an Euler pseudoprime.
Examples
========
>>> from sympy.ntheory.primetest import is_euler_pseudoprime
>>> from sympy.ntheory.factor_ import isprime
>>> for n in range(1, 1000):
... if is_euler_pseudoprime(n, 2) and not isprime(n):
... print(n)
341
561
References
==========
.. [1] https://en.wikipedia.org/wiki/Euler_pseudoprime
"""
n, a = as_int(n), as_int(a)
if a < 1:
raise ValueError("a should be an integer greater than 0")
if n < 1:
raise ValueError("n should be an integer greater than 0")
if n == 1:
return False
if a == 1:
return n == 2 or bool(n % 2) # (prime or odd composite)
if n % 2 == 0:
return n == 2
if gcd(n, a) != 1:
raise ValueError("The two numbers should be relatively prime")
return pow(a, (n - 1) // 2, n) in [1, n - 1]
def is_euler_jacobi_pseudoprime(n, a):
r"""Returns True if ``n`` is prime or is an odd composite integer that
is coprime to ``a`` and satisfy the modular arithmetic congruence relation:
.. math ::
a^{(n-1)/2} \equiv \left(\frac{a}{n}\right) \pmod{n}
(where mod refers to the modulo operation).
Parameters
==========
n : Integer
``n`` is a positive integer.
a : Integer
``a`` is a positive integer.
``a`` and ``n`` should be relatively prime.
Returns
=======
bool : If ``n`` is prime, it always returns ``True``.
The composite number that returns ``True`` is called an Euler-Jacobi pseudoprime.
Examples
========
>>> from sympy.ntheory.primetest import is_euler_jacobi_pseudoprime
>>> from sympy.ntheory.factor_ import isprime
>>> for n in range(1, 1000):
... if is_euler_jacobi_pseudoprime(n, 2) and not isprime(n):
... print(n)
561
References
==========
.. [1] https://en.wikipedia.org/wiki/Euler%E2%80%93Jacobi_pseudoprime
"""
n, a = as_int(n), as_int(a)
if a == 1:
return n == 2 or bool(n % 2)
return is_euler_prp(n, a)
def is_square(n, prep=True):
"""Return True if n == a * a for some integer a, else False.
If n is suspected of *not* being a square then this is a
quick method of confirming that it is not.
Examples
========
>>> from sympy.ntheory.primetest import is_square
>>> is_square(25)
True
>>> is_square(2)
False
References
==========
.. [1] https://mersenneforum.org/showpost.php?p=110896
See Also
========
sympy.core.intfunc.isqrt
"""
if prep:
n = as_int(n)
if n < 0:
return False
if n in (0, 1):
return True
return gmpy_is_square(n)
def _test(n, base, s, t):
"""Miller-Rabin strong pseudoprime test for one base.
Return False if n is definitely composite, True if n is
probably prime, with a probability greater than 3/4.
"""
# do the Fermat test
b = pow(base, t, n)
if b == 1 or b == n - 1:
return True
for _ in range(s - 1):
b = pow(b, 2, n)
if b == n - 1:
return True
# see I. Niven et al. "An Introduction to Theory of Numbers", page 78
if b == 1:
return False
return False
def mr(n, bases):
"""Perform a Miller-Rabin strong pseudoprime test on n using a
given list of bases/witnesses.
References
==========
.. [1] Richard Crandall & Carl Pomerance (2005), "Prime Numbers:
A Computational Perspective", Springer, 2nd edition, 135-138
A list of thresholds and the bases they require are here:
https://en.wikipedia.org/wiki/Miller%E2%80%93Rabin_primality_test#Deterministic_variants
Examples
========
>>> from sympy.ntheory.primetest import mr
>>> mr(1373651, [2, 3])
False
>>> mr(479001599, [31, 73])
True
"""
from sympy.polys.domains import ZZ
n = as_int(n)
if n < 2:
return False
# remove powers of 2 from n-1 (= t * 2**s)
s = bit_scan1(n - 1)
t = n >> s
for base in bases:
# Bases >= n are wrapped, bases < 2 are invalid
if base >= n:
base %= n
if base >= 2:
base = ZZ(base)
if not _test(n, base, s, t):
return False
return True
def _lucas_extrastrong_params(n):
"""Calculates the "extra strong" parameters (D, P, Q) for n.
Parameters
==========
n : int
positive odd integer
Returns
=======
D, P, Q: "extra strong" parameters.
``(0, 0, 0)`` if we find a nontrivial divisor of ``n``.
Examples
========
>>> from sympy.ntheory.primetest import _lucas_extrastrong_params
>>> _lucas_extrastrong_params(101)
(12, 4, 1)
>>> _lucas_extrastrong_params(15)
(0, 0, 0)
References
==========
.. [1] OEIS A217719: Extra Strong Lucas Pseudoprimes
https://oeis.org/A217719
.. [2] https://en.wikipedia.org/wiki/Lucas_pseudoprime
"""
for P in count(3):
D = P**2 - 4
j = jacobi(D, n)
if j == -1:
return (D, P, 1)
elif j == 0 and D % n:
return (0, 0, 0)
def is_lucas_prp(n):
"""Standard Lucas compositeness test with Selfridge parameters. Returns
False if n is definitely composite, and True if n is a Lucas probable
prime.
This is typically used in combination with the Miller-Rabin test.
References
==========
.. [1] Robert Baillie, Samuel S. Wagstaff, Lucas Pseudoprimes,
Math. Comp. Vol 35, Number 152 (1980), pp. 1391-1417,
https://doi.org/10.1090%2FS0025-5718-1980-0583518-6
http://mpqs.free.fr/LucasPseudoprimes.pdf
.. [2] OEIS A217120: Lucas Pseudoprimes
https://oeis.org/A217120
.. [3] https://en.wikipedia.org/wiki/Lucas_pseudoprime
Examples
========
>>> from sympy.ntheory.primetest import isprime, is_lucas_prp
>>> for i in range(10000):
... if is_lucas_prp(i) and not isprime(i):
... print(i)
323
377
1159
1829
3827
5459
5777
9071
9179
"""
n = as_int(n)
if n < 2:
return False
return is_selfridge_prp(n)
def is_strong_lucas_prp(n):
"""Strong Lucas compositeness test with Selfridge parameters. Returns
False if n is definitely composite, and True if n is a strong Lucas
probable prime.
This is often used in combination with the Miller-Rabin test, and
in particular, when combined with M-R base 2 creates the strong BPSW test.
References
==========
.. [1] Robert Baillie, Samuel S. Wagstaff, Lucas Pseudoprimes,
Math. Comp. Vol 35, Number 152 (1980), pp. 1391-1417,
https://doi.org/10.1090%2FS0025-5718-1980-0583518-6
http://mpqs.free.fr/LucasPseudoprimes.pdf
.. [2] OEIS A217255: Strong Lucas Pseudoprimes
https://oeis.org/A217255
.. [3] https://en.wikipedia.org/wiki/Lucas_pseudoprime
.. [4] https://en.wikipedia.org/wiki/Baillie-PSW_primality_test
Examples
========
>>> from sympy.ntheory.primetest import isprime, is_strong_lucas_prp
>>> for i in range(20000):
... if is_strong_lucas_prp(i) and not isprime(i):
... print(i)
5459
5777
10877
16109
18971
"""
n = as_int(n)
if n < 2:
return False
return is_strong_selfridge_prp(n)
def is_extra_strong_lucas_prp(n):
"""Extra Strong Lucas compositeness test. Returns False if n is
definitely composite, and True if n is an "extra strong" Lucas probable
prime.
The parameters are selected using P = 3, Q = 1, then incrementing P until
(D|n) == -1. The test itself is as defined in [1]_, from the
Mo and Jones preprint. The parameter selection and test are the same as
used in OEIS A217719, Perl's Math::Prime::Util, and the Lucas pseudoprime
page on Wikipedia.
It is 20-50% faster than the strong test.
Because of the different parameters selected, there is no relationship
between the strong Lucas pseudoprimes and extra strong Lucas pseudoprimes.
In particular, one is not a subset of the other.
References
==========
.. [1] Jon Grantham, Frobenius Pseudoprimes,
Math. Comp. Vol 70, Number 234 (2001), pp. 873-891,
https://doi.org/10.1090%2FS0025-5718-00-01197-2
.. [2] OEIS A217719: Extra Strong Lucas Pseudoprimes
https://oeis.org/A217719
.. [3] https://en.wikipedia.org/wiki/Lucas_pseudoprime
Examples
========
>>> from sympy.ntheory.primetest import isprime, is_extra_strong_lucas_prp
>>> for i in range(20000):
... if is_extra_strong_lucas_prp(i) and not isprime(i):
... print(i)
989
3239
5777
10877
"""
# Implementation notes:
# 1) the parameters differ from Thomas R. Nicely's. His parameter
# selection leads to pseudoprimes that overlap M-R tests, and
# contradict Baillie and Wagstaff's suggestion of (D|n) = -1.
# 2) The MathWorld page as of June 2013 specifies Q=-1. The Lucas
# sequence must have Q=1. See Grantham theorem 2.3, any of the
# references on the MathWorld page, or run it and see Q=-1 is wrong.
n = as_int(n)
if n == 2:
return True
if n < 2 or (n % 2) == 0:
return False
if gmpy_is_square(n):
return False
D, P, Q = _lucas_extrastrong_params(n)
if D == 0:
return False
# remove powers of 2 from n+1 (= k * 2**s)
s = bit_scan1(n + 1)
k = (n + 1) >> s
U, V, _ = _lucas_sequence(n, P, Q, k)
if U == 0 and (V == 2 or V == n - 2):
return True
for _ in range(1, s):
if V == 0:
return True
V = (V*V - 2) % n
return False
def proth_test(n):
r""" Test if the Proth number `n = k2^m + 1` is prime. where k is a positive odd number and `2^m > k`.
Parameters
==========
n : Integer
``n`` is Proth number
Returns
=======
bool : If ``True``, then ``n`` is the Proth prime
Raises
======
ValueError
If ``n`` is not Proth number.
Examples
========
>>> from sympy.ntheory.primetest import proth_test
>>> proth_test(41)
True
>>> proth_test(57)
False
References
==========
.. [1] https://en.wikipedia.org/wiki/Proth_prime
"""
n = as_int(n)
if n < 3:
raise ValueError("n is not Proth number")
m = bit_scan1(n - 1)
k = n >> m
if m < k.bit_length():
raise ValueError("n is not Proth number")
if n % 3 == 0:
return n == 3
if k % 3: # n % 12 == 5
return pow(3, n >> 1, n) == n - 1
# If `n` is a square number, then `jacobi(a, n) = 1` for any `a`
if gmpy_is_square(n):
return False
# `a` may be chosen at random.
# In any case, we want to find `a` such that `jacobi(a, n) = -1`.
for a in range(5, n):
j = jacobi(a, n)
if j == -1:
return pow(a, n >> 1, n) == n - 1
if j == 0:
return False
def _lucas_lehmer_primality_test(p):
r""" Test if the Mersenne number `M_p = 2^p-1` is prime.
Parameters
==========
p : int
``p`` is an odd prime number
Returns
=======
bool : If ``True``, then `M_p` is the Mersenne prime
Examples
========
>>> from sympy.ntheory.primetest import _lucas_lehmer_primality_test
>>> _lucas_lehmer_primality_test(5) # 2**5 - 1 = 31 is prime
True
>>> _lucas_lehmer_primality_test(11) # 2**11 - 1 = 2047 is not prime
False
See Also
========
is_mersenne_prime
References
==========
.. [1] https://en.wikipedia.org/wiki/Lucas%E2%80%93Lehmer_primality_test
"""
v = 4
m = 2**p - 1
for _ in range(p - 2):
v = pow(v, 2, m) - 2
return v == 0
def is_mersenne_prime(n):
"""Returns True if ``n`` is a Mersenne prime, else False.
A Mersenne prime is a prime number having the form `2^i - 1`.
Examples
========
>>> from sympy.ntheory.factor_ import is_mersenne_prime
>>> is_mersenne_prime(6)
False
>>> is_mersenne_prime(127)
True
References
==========
.. [1] https://mathworld.wolfram.com/MersennePrime.html
"""
n = as_int(n)
if n < 1:
return False
if n & (n + 1):
# n is not Mersenne number
return False
p = n.bit_length()
if p in MERSENNE_PRIME_EXPONENTS:
return True
if p < 65_000_000 or not isprime(p):
# According to GIMPS, verification was completed on September 19, 2023 for p less than 65 million.
# https://www.mersenne.org/report_milestones/
# If p is composite number, then n=2**p-1 is composite number.
return False
result = _lucas_lehmer_primality_test(p)
if result:
raise ValueError(filldedent('''
This Mersenne Prime, 2^%s - 1, should
be added to SymPy's known values.''' % p))
return result
def isprime(n):
"""
Test if n is a prime number (True) or not (False). For n < 2^64 the
answer is definitive; larger n values have a small probability of actually
being pseudoprimes.
Negative numbers (e.g. -2) are not considered prime.
The first step is looking for trivial factors, which if found enables
a quick return. Next, if the sieve is large enough, use bisection search
on the sieve. For small numbers, a set of deterministic Miller-Rabin
tests are performed with bases that are known to have no counterexamples
in their range. Finally if the number is larger than 2^64, a strong
BPSW test is performed. While this is a probable prime test and we
believe counterexamples exist, there are no known counterexamples.
Examples
========
>>> from sympy.ntheory import isprime
>>> isprime(13)
True
>>> isprime(15)
False
Notes
=====
This routine is intended only for integer input, not numerical
expressions which may represent numbers. Floats are also
rejected as input because they represent numbers of limited
precision. While it is tempting to permit 7.0 to represent an
integer there are errors that may "pass silently" if this is
allowed:
>>> from sympy import Float, S
>>> int(1e3) == 1e3 == 10**3
True
>>> int(1e23) == 1e23
True
>>> int(1e23) == 10**23
False
>>> near_int = 1 + S(1)/10**19
>>> near_int == int(near_int)
False
>>> n = Float(near_int, 10) # truncated by precision
>>> n % 1 == 0
True
>>> n = Float(near_int, 20)
>>> n % 1 == 0
False
See Also
========
sympy.ntheory.generate.primerange : Generates all primes in a given range
sympy.functions.combinatorial.numbers.primepi : Return the number of primes less than or equal to n
sympy.ntheory.generate.prime : Return the nth prime
References
==========
.. [1] https://en.wikipedia.org/wiki/Strong_pseudoprime
.. [2] Robert Baillie, Samuel S. Wagstaff, Lucas Pseudoprimes,
Math. Comp. Vol 35, Number 152 (1980), pp. 1391-1417,
https://doi.org/10.1090%2FS0025-5718-1980-0583518-6
http://mpqs.free.fr/LucasPseudoprimes.pdf
.. [3] https://en.wikipedia.org/wiki/Baillie-PSW_primality_test
"""
n = as_int(n)
# Step 1, do quick composite testing via trial division. The individual
# modulo tests benchmark faster than one or two primorial igcds for me.
# The point here is just to speedily handle small numbers and many
# composites. Step 2 only requires that n <= 2 get handled here.
if n in [2, 3, 5]:
return True
if n < 2 or (n % 2) == 0 or (n % 3) == 0 or (n % 5) == 0:
return False
if n < 49:
return True
if (n % 7) == 0 or (n % 11) == 0 or (n % 13) == 0 or (n % 17) == 0 or \
(n % 19) == 0 or (n % 23) == 0 or (n % 29) == 0 or (n % 31) == 0 or \
(n % 37) == 0 or (n % 41) == 0 or (n % 43) == 0 or (n % 47) == 0:
return False
if n < 2809:
return True
if n < 65077:
# There are only five Euler pseudoprimes with a least prime factor greater than 47
return pow(2, n >> 1, n) in [1, n - 1] and n not in [8321, 31621, 42799, 49141, 49981]
# bisection search on the sieve if the sieve is large enough
from sympy.ntheory.generate import sieve as s
if n <= s._list[-1]:
l, u = s.search(n)
return l == u
# If we have GMPY2, skip straight to step 3 and do a strong BPSW test.
# This should be a bit faster than our step 2, and for large values will
# be a lot faster than our step 3 (C+GMP vs. Python).
if _gmpy is not None:
return is_strong_bpsw_prp(n)
# Step 2: deterministic Miller-Rabin testing for numbers < 2^64. See:
# https://miller-rabin.appspot.com/
# for lists. We have made sure the M-R routine will successfully handle
# bases larger than n, so we can use the minimal set.
# In September 2015 deterministic numbers were extended to over 2^81.
# https://arxiv.org/pdf/1509.00864.pdf
# https://oeis.org/A014233
if n < 341531:
return mr(n, [9345883071009581737])
if n < 885594169:
return mr(n, [725270293939359937, 3569819667048198375])
if n < 350269456337:
return mr(n, [4230279247111683200, 14694767155120705706, 16641139526367750375])
if n < 55245642489451:
return mr(n, [2, 141889084524735, 1199124725622454117, 11096072698276303650])
if n < 7999252175582851:
return mr(n, [2, 4130806001517, 149795463772692060, 186635894390467037, 3967304179347715805])
if n < 585226005592931977:
return mr(n, [2, 123635709730000, 9233062284813009, 43835965440333360, 761179012939631437, 1263739024124850375])
if n < 18446744073709551616:
return mr(n, [2, 325, 9375, 28178, 450775, 9780504, 1795265022])
if n < 318665857834031151167461:
return mr(n, [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37])
if n < 3317044064679887385961981:
return mr(n, [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41])
# We could do this instead at any point:
#if n < 18446744073709551616:
# return mr(n, [2]) and is_extra_strong_lucas_prp(n)
# Here are tests that are safe for MR routines that don't understand
# large bases.
#if n < 9080191:
# return mr(n, [31, 73])
#if n < 19471033:
# return mr(n, [2, 299417])
#if n < 38010307:
# return mr(n, [2, 9332593])
#if n < 316349281:
# return mr(n, [11000544, 31481107])
#if n < 4759123141:
# return mr(n, [2, 7, 61])
#if n < 105936894253:
# return mr(n, [2, 1005905886, 1340600841])
#if n < 31858317218647:
# return mr(n, [2, 642735, 553174392, 3046413974])
#if n < 3071837692357849:
# return mr(n, [2, 75088, 642735, 203659041, 3613982119])
#if n < 18446744073709551616:
# return mr(n, [2, 325, 9375, 28178, 450775, 9780504, 1795265022])
# Step 3: BPSW.
#
# Time for isprime(10**2000 + 4561), no gmpy or gmpy2 installed
# 44.0s old isprime using 46 bases
# 5.3s strong BPSW + one random base
# 4.3s extra strong BPSW + one random base
# 4.1s strong BPSW
# 3.2s extra strong BPSW
# Classic BPSW from page 1401 of the paper. See alternate ideas below.
return is_strong_bpsw_prp(n)
# Using extra strong test, which is somewhat faster
#return mr(n, [2]) and is_extra_strong_lucas_prp(n)
# Add a random M-R base
#import random
#return mr(n, [2, random.randint(3, n-1)]) and is_strong_lucas_prp(n)
def is_gaussian_prime(num):
r"""Test if num is a Gaussian prime number.
References
==========
.. [1] https://oeis.org/wiki/Gaussian_primes
"""
num = sympify(num)
a, b = num.as_real_imag()
a = as_int(a, strict=False)
b = as_int(b, strict=False)
if a == 0:
b = abs(b)
return isprime(b) and b % 4 == 3
elif b == 0:
a = abs(a)
return isprime(a) and a % 4 == 3
return isprime(a**2 + b**2)
PK ]ZZZcT�G�G �G sympy/ntheory/qs.pyfrom sympy.core.random import _randint
from sympy.external.gmpy import gcd, invert, sqrt as isqrt
from sympy.ntheory.residue_ntheory import _sqrt_mod_prime_power
from sympy.ntheory import isprime
from math import log, sqrt
class SievePolynomial:
def __init__(self, modified_coeff=(), a=None, b=None):
"""This class denotes the seive polynomial.
If ``g(x) = (a*x + b)**2 - N``. `g(x)` can be expanded
to ``a*x**2 + 2*a*b*x + b**2 - N``, so the coefficient
is stored in the form `[a**2, 2*a*b, b**2 - N]`. This
ensures faster `eval` method because we dont have to
perform `a**2, 2*a*b, b**2` every time we call the
`eval` method. As multiplication is more expensive
than addition, by using modified_coefficient we get
a faster seiving process.
Parameters
==========
modified_coeff : modified_coefficient of sieve polynomial
a : parameter of the sieve polynomial
b : parameter of the sieve polynomial
"""
self.modified_coeff = modified_coeff
self.a = a
self.b = b
def eval(self, x):
"""
Compute the value of the sieve polynomial at point x.
Parameters
==========
x : Integer parameter for sieve polynomial
"""
ans = 0
for coeff in self.modified_coeff:
ans *= x
ans += coeff
return ans
class FactorBaseElem:
"""This class stores an element of the `factor_base`.
"""
def __init__(self, prime, tmem_p, log_p):
"""
Initialization of factor_base_elem.
Parameters
==========
prime : prime number of the factor_base
tmem_p : Integer square root of x**2 = n mod prime
log_p : Compute Natural Logarithm of the prime
"""
self.prime = prime
self.tmem_p = tmem_p
self.log_p = log_p
self.soln1 = None
self.soln2 = None
self.a_inv = None
self.b_ainv = None
def _generate_factor_base(prime_bound, n):
"""Generate `factor_base` for Quadratic Sieve. The `factor_base`
consists of all the points whose ``legendre_symbol(n, p) == 1``
and ``p < num_primes``. Along with the prime `factor_base` also stores
natural logarithm of prime and the residue n modulo p.
It also returns the of primes numbers in the `factor_base` which are
close to 1000 and 5000.
Parameters
==========
prime_bound : upper prime bound of the factor_base
n : integer to be factored
"""
from sympy.ntheory.generate import sieve
factor_base = []
idx_1000, idx_5000 = None, None
for prime in sieve.primerange(1, prime_bound):
if pow(n, (prime - 1) // 2, prime) == 1:
if prime > 1000 and idx_1000 is None:
idx_1000 = len(factor_base) - 1
if prime > 5000 and idx_5000 is None:
idx_5000 = len(factor_base) - 1
residue = _sqrt_mod_prime_power(n, prime, 1)[0]
log_p = round(log(prime)*2**10)
factor_base.append(FactorBaseElem(prime, residue, log_p))
return idx_1000, idx_5000, factor_base
def _initialize_first_polynomial(N, M, factor_base, idx_1000, idx_5000, seed=None):
"""This step is the initialization of the 1st sieve polynomial.
Here `a` is selected as a product of several primes of the factor_base
such that `a` is about to ``sqrt(2*N) / M``. Other initial values of
factor_base elem are also initialized which includes a_inv, b_ainv, soln1,
soln2 which are used when the sieve polynomial is changed. The b_ainv
is required for fast polynomial change as we do not have to calculate
`2*b*invert(a, prime)` every time.
We also ensure that the `factor_base` primes which make `a` are between
1000 and 5000.
Parameters
==========
N : Number to be factored
M : sieve interval
factor_base : factor_base primes
idx_1000 : index of prime number in the factor_base near 1000
idx_5000 : index of prime number in the factor_base near to 5000
seed : Generate pseudoprime numbers
"""
randint = _randint(seed)
approx_val = sqrt(2*N) / M
# `a` is a parameter of the sieve polynomial and `q` is the prime factors of `a`
# randomly search for a combination of primes whose multiplication is close to approx_val
# This multiplication of primes will be `a` and the primes will be `q`
# `best_a` denotes that `a` is close to approx_val in the random search of combination
best_a, best_q, best_ratio = None, None, None
start = 0 if idx_1000 is None else idx_1000
end = len(factor_base) - 1 if idx_5000 is None else idx_5000
for _ in range(50):
a = 1
q = []
while(a < approx_val):
rand_p = 0
while(rand_p == 0 or rand_p in q):
rand_p = randint(start, end)
p = factor_base[rand_p].prime
a *= p
q.append(rand_p)
ratio = a / approx_val
if best_ratio is None or abs(ratio - 1) < abs(best_ratio - 1):
best_q = q
best_a = a
best_ratio = ratio
a = best_a
q = best_q
B = []
for val in q:
q_l = factor_base[val].prime
gamma = factor_base[val].tmem_p * invert(a // q_l, q_l) % q_l
if gamma > q_l / 2:
gamma = q_l - gamma
B.append(a//q_l*gamma)
b = sum(B)
g = SievePolynomial([a*a, 2*a*b, b*b - N], a, b)
for fb in factor_base:
if a % fb.prime == 0:
continue
fb.a_inv = invert(a, fb.prime)
fb.b_ainv = [2*b_elem*fb.a_inv % fb.prime for b_elem in B]
fb.soln1 = (fb.a_inv*(fb.tmem_p - b)) % fb.prime
fb.soln2 = (fb.a_inv*(-fb.tmem_p - b)) % fb.prime
return g, B
def _initialize_ith_poly(N, factor_base, i, g, B):
"""Initialization stage of ith poly. After we finish sieving 1`st polynomial
here we quickly change to the next polynomial from which we will again
start sieving. Suppose we generated ith sieve polynomial and now we
want to generate (i + 1)th polynomial, where ``1 <= i <= 2**(j - 1) - 1``
where `j` is the number of prime factors of the coefficient `a`
then this function can be used to go to the next polynomial. If
``i = 2**(j - 1) - 1`` then go to _initialize_first_polynomial stage.
Parameters
==========
N : number to be factored
factor_base : factor_base primes
i : integer denoting ith polynomial
g : (i - 1)th polynomial
B : array that stores a//q_l*gamma
"""
from sympy.functions.elementary.integers import ceiling
v = 1
j = i
while(j % 2 == 0):
v += 1
j //= 2
if ceiling(i / (2**v)) % 2 == 1:
neg_pow = -1
else:
neg_pow = 1
b = g.b + 2*neg_pow*B[v - 1]
a = g.a
g = SievePolynomial([a*a, 2*a*b, b*b - N], a, b)
for fb in factor_base:
if a % fb.prime == 0:
continue
fb.soln1 = (fb.soln1 - neg_pow*fb.b_ainv[v - 1]) % fb.prime
fb.soln2 = (fb.soln2 - neg_pow*fb.b_ainv[v - 1]) % fb.prime
return g
def _gen_sieve_array(M, factor_base):
"""Sieve Stage of the Quadratic Sieve. For every prime in the factor_base
that does not divide the coefficient `a` we add log_p over the sieve_array
such that ``-M <= soln1 + i*p <= M`` and ``-M <= soln2 + i*p <= M`` where `i`
is an integer. When p = 2 then log_p is only added using
``-M <= soln1 + i*p <= M``.
Parameters
==========
M : sieve interval
factor_base : factor_base primes
"""
sieve_array = [0]*(2*M + 1)
for factor in factor_base:
if factor.soln1 is None: #The prime does not divides a
continue
for idx in range((M + factor.soln1) % factor.prime, 2*M, factor.prime):
sieve_array[idx] += factor.log_p
if factor.prime == 2:
continue
#if prime is 2 then sieve only with soln_1_p
for idx in range((M + factor.soln2) % factor.prime, 2*M, factor.prime):
sieve_array[idx] += factor.log_p
return sieve_array
def _check_smoothness(num, factor_base):
"""Here we check that if `num` is a smooth number or not. If `a` is a smooth
number then it returns a vector of prime exponents modulo 2. For example
if a = 2 * 5**2 * 7**3 and the factor base contains {2, 3, 5, 7} then
`a` is a smooth number and this function returns ([1, 0, 0, 1], True). If
`a` is a partial relation which means that `a` a has one prime factor
greater than the `factor_base` then it returns `(a, False)` which denotes `a`
is a partial relation.
Parameters
==========
a : integer whose smootheness is to be checked
factor_base : factor_base primes
"""
vec = []
if num < 0:
vec.append(1)
num *= -1
else:
vec.append(0)
#-1 is not included in factor_base add -1 in vector
for factor in factor_base:
if num % factor.prime != 0:
vec.append(0)
continue
factor_exp = 0
while num % factor.prime == 0:
factor_exp += 1
num //= factor.prime
vec.append(factor_exp % 2)
if num == 1:
return vec, True
if isprime(num):
return num, False
return None, None
def _trial_division_stage(N, M, factor_base, sieve_array, sieve_poly, partial_relations, ERROR_TERM):
"""Trial division stage. Here we trial divide the values generetated
by sieve_poly in the sieve interval and if it is a smooth number then
it is stored in `smooth_relations`. Moreover, if we find two partial relations
with same large prime then they are combined to form a smooth relation.
First we iterate over sieve array and look for values which are greater
than accumulated_val, as these values have a high chance of being smooth
number. Then using these values we find smooth relations.
In general, let ``t**2 = u*p modN`` and ``r**2 = v*p modN`` be two partial relations
with the same large prime p. Then they can be combined ``(t*r/p)**2 = u*v modN``
to form a smooth relation.
Parameters
==========
N : Number to be factored
M : sieve interval
factor_base : factor_base primes
sieve_array : stores log_p values
sieve_poly : polynomial from which we find smooth relations
partial_relations : stores partial relations with one large prime
ERROR_TERM : error term for accumulated_val
"""
sqrt_n = isqrt(N)
accumulated_val = log(M * sqrt_n)*2**10 - ERROR_TERM
smooth_relations = []
proper_factor = set()
partial_relation_upper_bound = 128*factor_base[-1].prime
for idx, val in enumerate(sieve_array):
if val < accumulated_val:
continue
x = idx - M
v = sieve_poly.eval(x)
vec, is_smooth = _check_smoothness(v, factor_base)
if is_smooth is None:#Neither smooth nor partial
continue
u = sieve_poly.a*x + sieve_poly.b
# Update the partial relation
# If 2 partial relation with same large prime is found then generate smooth relation
if is_smooth is False:#partial relation found
large_prime = vec
#Consider the large_primes under 128*F
if large_prime > partial_relation_upper_bound:
continue
if large_prime not in partial_relations:
partial_relations[large_prime] = (u, v)
continue
else:
u_prev, v_prev = partial_relations[large_prime]
partial_relations.pop(large_prime)
try:
large_prime_inv = invert(large_prime, N)
except ZeroDivisionError:#if large_prime divides N
proper_factor.add(large_prime)
continue
u = u*u_prev*large_prime_inv
v = v*v_prev // (large_prime*large_prime)
vec, is_smooth = _check_smoothness(v, factor_base)
#assert u*u % N == v % N
smooth_relations.append((u, v, vec))
return smooth_relations, proper_factor
#LINEAR ALGEBRA STAGE
def _build_matrix(smooth_relations):
"""Build a 2D matrix from smooth relations.
Parameters
==========
smooth_relations : Stores smooth relations
"""
matrix = []
for s_relation in smooth_relations:
matrix.append(s_relation[2])
return matrix
def _gauss_mod_2(A):
"""Fast gaussian reduction for modulo 2 matrix.
Parameters
==========
A : Matrix
Examples
========
>>> from sympy.ntheory.qs import _gauss_mod_2
>>> _gauss_mod_2([[0, 1, 1], [1, 0, 1], [0, 1, 0], [1, 1, 1]])
([[[1, 0, 1], 3]],
[True, True, True, False],
[[0, 1, 0], [1, 0, 0], [0, 0, 1], [1, 0, 1]])
Reference
==========
.. [1] A fast algorithm for gaussian elimination over GF(2) and
its implementation on the GAPP. Cetin K.Koc, Sarath N.Arachchige"""
import copy
matrix = copy.deepcopy(A)
row = len(matrix)
col = len(matrix[0])
mark = [False]*row
for c in range(col):
for r in range(row):
if matrix[r][c] == 1:
break
mark[r] = True
for c1 in range(col):
if c1 == c:
continue
if matrix[r][c1] == 1:
for r2 in range(row):
matrix[r2][c1] = (matrix[r2][c1] + matrix[r2][c]) % 2
dependent_row = []
for idx, val in enumerate(mark):
if val == False:
dependent_row.append([matrix[idx], idx])
return dependent_row, mark, matrix
def _find_factor(dependent_rows, mark, gauss_matrix, index, smooth_relations, N):
"""Finds proper factor of N. Here, transform the dependent rows as a
combination of independent rows of the gauss_matrix to form the desired
relation of the form ``X**2 = Y**2 modN``. After obtaining the desired relation
we obtain a proper factor of N by `gcd(X - Y, N)`.
Parameters
==========
dependent_rows : denoted dependent rows in the reduced matrix form
mark : boolean array to denoted dependent and independent rows
gauss_matrix : Reduced form of the smooth relations matrix
index : denoted the index of the dependent_rows
smooth_relations : Smooth relations vectors matrix
N : Number to be factored
"""
idx_in_smooth = dependent_rows[index][1]
independent_u = [smooth_relations[idx_in_smooth][0]]
independent_v = [smooth_relations[idx_in_smooth][1]]
dept_row = dependent_rows[index][0]
for idx, val in enumerate(dept_row):
if val == 1:
for row in range(len(gauss_matrix)):
if gauss_matrix[row][idx] == 1 and mark[row] == True:
independent_u.append(smooth_relations[row][0])
independent_v.append(smooth_relations[row][1])
break
u = 1
v = 1
for i in independent_u:
u *= i
for i in independent_v:
v *= i
#assert u**2 % N == v % N
v = isqrt(v)
return gcd(u - v, N)
def qs(N, prime_bound, M, ERROR_TERM=25, seed=1234):
"""Performs factorization using Self-Initializing Quadratic Sieve.
In SIQS, let N be a number to be factored, and this N should not be a
perfect power. If we find two integers such that ``X**2 = Y**2 modN`` and
``X != +-Y modN``, then `gcd(X + Y, N)` will reveal a proper factor of N.
In order to find these integers X and Y we try to find relations of form
t**2 = u modN where u is a product of small primes. If we have enough of
these relations then we can form ``(t1*t2...ti)**2 = u1*u2...ui modN`` such that
the right hand side is a square, thus we found a relation of ``X**2 = Y**2 modN``.
Here, several optimizations are done like using multiple polynomials for
sieving, fast changing between polynomials and using partial relations.
The use of partial relations can speeds up the factoring by 2 times.
Parameters
==========
N : Number to be Factored
prime_bound : upper bound for primes in the factor base
M : Sieve Interval
ERROR_TERM : Error term for checking smoothness
threshold : Extra smooth relations for factorization
seed : generate pseudo prime numbers
Examples
========
>>> from sympy.ntheory import qs
>>> qs(25645121643901801, 2000, 10000)
{5394769, 4753701529}
>>> qs(9804659461513846513, 2000, 10000)
{4641991, 2112166839943}
References
==========
.. [1] https://pdfs.semanticscholar.org/5c52/8a975c1405bd35c65993abf5a4edb667c1db.pdf
.. [2] https://www.rieselprime.de/ziki/Self-initializing_quadratic_sieve
"""
ERROR_TERM*=2**10
idx_1000, idx_5000, factor_base = _generate_factor_base(prime_bound, N)
smooth_relations = []
ith_poly = 0
partial_relations = {}
proper_factor = set()
threshold = 5*len(factor_base) // 100
while True:
if ith_poly == 0:
ith_sieve_poly, B_array = _initialize_first_polynomial(N, M, factor_base, idx_1000, idx_5000)
else:
ith_sieve_poly = _initialize_ith_poly(N, factor_base, ith_poly, ith_sieve_poly, B_array)
ith_poly += 1
if ith_poly >= 2**(len(B_array) - 1): # time to start with a new sieve polynomial
ith_poly = 0
sieve_array = _gen_sieve_array(M, factor_base)
s_rel, p_f = _trial_division_stage(N, M, factor_base, sieve_array, ith_sieve_poly, partial_relations, ERROR_TERM)
smooth_relations += s_rel
proper_factor |= p_f
if len(smooth_relations) >= len(factor_base) + threshold:
break
matrix = _build_matrix(smooth_relations)
dependent_row, mark, gauss_matrix = _gauss_mod_2(matrix)
N_copy = N
for index in range(len(dependent_row)):
factor = _find_factor(dependent_row, mark, gauss_matrix, index, smooth_relations, N)
if factor > 1 and factor < N:
proper_factor.add(factor)
while(N_copy % factor == 0):
N_copy //= factor
if isprime(N_copy):
proper_factor.add(N_copy)
break
if(N_copy == 1):
break
return proper_factor
PK ]ZZZ������ �� sympy/ntheory/residue_ntheory.pyfrom __future__ import annotations
from sympy.external.gmpy import (gcd, lcm, invert, sqrt, jacobi,
bit_scan1, remove)
from sympy.polys import Poly
from sympy.polys.domains import ZZ
from sympy.polys.galoistools import gf_crt1, gf_crt2, linear_congruence, gf_csolve
from .primetest import isprime
from .generate import primerange
from .factor_ import factorint, _perfect_power
from .modular import crt
from sympy.utilities.decorator import deprecated
from sympy.utilities.memoization import recurrence_memo
from sympy.utilities.misc import as_int
from sympy.utilities.iterables import iproduct
from sympy.core.random import _randint, randint
from itertools import product
def n_order(a, n):
r""" Returns the order of ``a`` modulo ``n``.
Explanation
===========
The order of ``a`` modulo ``n`` is the smallest integer
``k`` such that `a^k` leaves a remainder of 1 with ``n``.
Parameters
==========
a : integer
n : integer, n > 1. a and n should be relatively prime
Returns
=======
int : the order of ``a`` modulo ``n``
Raises
======
ValueError
If `n \le 1` or `\gcd(a, n) \neq 1`.
If ``a`` or ``n`` is not an integer.
Examples
========
>>> from sympy.ntheory import n_order
>>> n_order(3, 7)
6
>>> n_order(4, 7)
3
See Also
========
is_primitive_root
We say that ``a`` is a primitive root of ``n``
when the order of ``a`` modulo ``n`` equals ``totient(n)``
"""
a, n = as_int(a), as_int(n)
if n <= 1:
raise ValueError("n should be an integer greater than 1")
a = a % n
# Trivial
if a == 1:
return 1
if gcd(a, n) != 1:
raise ValueError("The two numbers should be relatively prime")
a_order = 1
for p, e in factorint(n).items():
pe = p**e
pe_order = (p - 1) * p**(e - 1)
factors = factorint(p - 1)
if e > 1:
factors[p] = e - 1
order = 1
for px, ex in factors.items():
x = pow(a, pe_order // px**ex, pe)
while x != 1:
x = pow(x, px, pe)
order *= px
a_order = lcm(a_order, order)
return int(a_order)
def _primitive_root_prime_iter(p):
r""" Generates the primitive roots for a prime ``p``.
Explanation
===========
The primitive roots generated are not necessarily sorted.
However, the first one is the smallest primitive root.
Find the element whose order is ``p-1`` from the smaller one.
If we can find the first primitive root ``g``, we can use the following theorem.
.. math ::
\operatorname{ord}(g^k) = \frac{\operatorname{ord}(g)}{\gcd(\operatorname{ord}(g), k)}
From the assumption that `\operatorname{ord}(g)=p-1`,
it is a necessary and sufficient condition for
`\operatorname{ord}(g^k)=p-1` that `\gcd(p-1, k)=1`.
Parameters
==========
p : odd prime
Yields
======
int
the primitive roots of ``p``
Examples
========
>>> from sympy.ntheory.residue_ntheory import _primitive_root_prime_iter
>>> sorted(_primitive_root_prime_iter(19))
[2, 3, 10, 13, 14, 15]
References
==========
.. [1] W. Stein "Elementary Number Theory" (2011), page 44
"""
if p == 3:
yield 2
return
# Let p = +-1 (mod 4a). Legendre symbol (a/p) = 1, so `a` is not the primitive root.
# Corollary : If p = +-1 (mod 8), then 2 is not the primitive root of p.
g_min = 3 if p % 8 in [1, 7] else 2
if p < 41:
# small case
g = 5 if p == 23 else g_min
else:
v = [(p - 1) // i for i in factorint(p - 1).keys()]
for g in range(g_min, p):
if all(pow(g, pw, p) != 1 for pw in v):
break
yield g
# g**k is the primitive root of p iff gcd(p - 1, k) = 1
for k in range(3, p, 2):
if gcd(p - 1, k) == 1:
yield pow(g, k, p)
def _primitive_root_prime_power_iter(p, e):
r""" Generates the primitive roots of `p^e`.
Explanation
===========
Let ``g`` be the primitive root of ``p``.
If `g^{p-1} \not\equiv 1 \pmod{p^2}`, then ``g`` is primitive root of `p^e`.
Thus, if we find a primitive root ``g`` of ``p``,
then `g, g+p, g+2p, \ldots, g+(p-1)p` are primitive roots of `p^2` except one.
That one satisfies `\hat{g}^{p-1} \equiv 1 \pmod{p^2}`.
If ``h`` is the primitive root of `p^2`,
then `h, h+p^2, h+2p^2, \ldots, h+(p^{e-2}-1)p^e` are primitive roots of `p^e`.
Parameters
==========
p : odd prime
e : positive integer
Yields
======
int
the primitive roots of `p^e`
Examples
========
>>> from sympy.ntheory.residue_ntheory import _primitive_root_prime_power_iter
>>> sorted(_primitive_root_prime_power_iter(5, 2))
[2, 3, 8, 12, 13, 17, 22, 23]
"""
if e == 1:
yield from _primitive_root_prime_iter(p)
else:
p2 = p**2
for g in _primitive_root_prime_iter(p):
t = (g - pow(g, 2 - p, p2)) % p2
for k in range(0, p2, p):
if k != t:
yield from (g + k + m for m in range(0, p**e, p2))
def _primitive_root_prime_power2_iter(p, e):
r""" Generates the primitive roots of `2p^e`.
Explanation
===========
If ``g`` is the primitive root of ``p**e``,
then the odd one of ``g`` and ``g+p**e`` is the primitive root of ``2*p**e``.
Parameters
==========
p : odd prime
e : positive integer
Yields
======
int
the primitive roots of `2p^e`
Examples
========
>>> from sympy.ntheory.residue_ntheory import _primitive_root_prime_power2_iter
>>> sorted(_primitive_root_prime_power2_iter(5, 2))
[3, 13, 17, 23, 27, 33, 37, 47]
"""
for g in _primitive_root_prime_power_iter(p, e):
if g % 2 == 1:
yield g
else:
yield g + p**e
def primitive_root(p, smallest=True):
r""" Returns a primitive root of ``p`` or None.
Explanation
===========
For the definition of primitive root,
see the explanation of ``is_primitive_root``.
The primitive root of ``p`` exist only for
`p = 2, 4, q^e, 2q^e` (``q`` is an odd prime).
Now, if we know the primitive root of ``q``,
we can calculate the primitive root of `q^e`,
and if we know the primitive root of `q^e`,
we can calculate the primitive root of `2q^e`.
When there is no need to find the smallest primitive root,
this property can be used to obtain a fast primitive root.
On the other hand, when we want the smallest primitive root,
we naively determine whether it is a primitive root or not.
Parameters
==========
p : integer, p > 1
smallest : if True the smallest primitive root is returned or None
Returns
=======
int | None :
If the primitive root exists, return the primitive root of ``p``.
If not, return None.
Raises
======
ValueError
If `p \le 1` or ``p`` is not an integer.
Examples
========
>>> from sympy.ntheory.residue_ntheory import primitive_root
>>> primitive_root(19)
2
>>> primitive_root(21) is None
True
>>> primitive_root(50, smallest=False)
27
See Also
========
is_primitive_root
References
==========
.. [1] W. Stein "Elementary Number Theory" (2011), page 44
.. [2] P. Hackman "Elementary Number Theory" (2009), Chapter C
"""
p = as_int(p)
if p <= 1:
raise ValueError("p should be an integer greater than 1")
if p <= 4:
return p - 1
p_even = p % 2 == 0
if not p_even:
q = p # p is odd
elif p % 4:
q = p//2 # p had 1 factor of 2
else:
return None # p had more than one factor of 2
if isprime(q):
e = 1
else:
m = _perfect_power(q, 3)
if not m:
return None
q, e = m
if not isprime(q):
return None
if not smallest:
if p_even:
return next(_primitive_root_prime_power2_iter(q, e))
return next(_primitive_root_prime_power_iter(q, e))
if p_even:
for i in range(3, p, 2):
if i % q and is_primitive_root(i, p):
return i
g = next(_primitive_root_prime_iter(q))
if e == 1 or pow(g, q - 1, q**2) != 1:
return g
for i in range(g + 1, p):
if i % q and is_primitive_root(i, p):
return i
def is_primitive_root(a, p):
r""" Returns True if ``a`` is a primitive root of ``p``.
Explanation
===========
``a`` is said to be the primitive root of ``p`` if `\gcd(a, p) = 1` and
`\phi(p)` is the smallest positive number s.t.
`a^{\phi(p)} \equiv 1 \pmod{p}`.
where `\phi(p)` is Euler's totient function.
The primitive root of ``p`` exist only for
`p = 2, 4, q^e, 2q^e` (``q`` is an odd prime).
Hence, if it is not such a ``p``, it returns False.
To determine the primitive root, we need to know
the prime factorization of ``q-1``.
The hardness of the determination depends on this complexity.
Parameters
==========
a : integer
p : integer, ``p`` > 1. ``a`` and ``p`` should be relatively prime
Returns
=======
bool : If True, ``a`` is the primitive root of ``p``.
Raises
======
ValueError
If `p \le 1` or `\gcd(a, p) \neq 1`.
If ``a`` or ``p`` is not an integer.
Examples
========
>>> from sympy.functions.combinatorial.numbers import totient
>>> from sympy.ntheory import is_primitive_root, n_order
>>> is_primitive_root(3, 10)
True
>>> is_primitive_root(9, 10)
False
>>> n_order(3, 10) == totient(10)
True
>>> n_order(9, 10) == totient(10)
False
See Also
========
primitive_root
"""
a, p = as_int(a), as_int(p)
if p <= 1:
raise ValueError("p should be an integer greater than 1")
a = a % p
if gcd(a, p) != 1:
raise ValueError("The two numbers should be relatively prime")
# Primitive root of p exist only for
# p = 2, 4, q**e, 2*q**e (q is odd prime)
if p <= 4:
# The primitive root is only p-1.
return a == p - 1
if p % 2:
q = p # p is odd
elif p % 4:
q = p//2 # p had 1 factor of 2
else:
return False # p had more than one factor of 2
if isprime(q):
group_order = q - 1
factors = factorint(q - 1).keys()
else:
m = _perfect_power(q, 3)
if not m:
return False
q, e = m
if not isprime(q):
return False
group_order = q**(e - 1)*(q - 1)
factors = set(factorint(q - 1).keys())
factors.add(q)
return all(pow(a, group_order // prime, p) != 1 for prime in factors)
def _sqrt_mod_tonelli_shanks(a, p):
"""
Returns the square root in the case of ``p`` prime with ``p == 1 (mod 8)``
Assume that the root exists.
Parameters
==========
a : int
p : int
prime number. should be ``p % 8 == 1``
Returns
=======
int : Generally, there are two roots, but only one is returned.
Which one is returned is random.
Examples
========
>>> from sympy.ntheory.residue_ntheory import _sqrt_mod_tonelli_shanks
>>> _sqrt_mod_tonelli_shanks(2, 17) in [6, 11]
True
References
==========
.. [1] Carl Pomerance, Richard Crandall, Prime Numbers: A Computational Perspective,
2nd Edition (2005), page 101, ISBN:978-0387252827
"""
s = bit_scan1(p - 1)
t = p >> s
# find a non-quadratic residue
if p % 12 == 5:
# Legendre symbol (3/p) == -1 if p % 12 in [5, 7]
d = 3
elif p % 5 in [2, 3]:
# Legendre symbol (5/p) == -1 if p % 5 in [2, 3]
d = 5
else:
while 1:
d = randint(6, p - 1)
if jacobi(d, p) == -1:
break
#assert legendre_symbol(d, p) == -1
A = pow(a, t, p)
D = pow(d, t, p)
m = 0
for i in range(s):
adm = A*pow(D, m, p) % p
adm = pow(adm, 2**(s - 1 - i), p)
if adm % p == p - 1:
m += 2**i
#assert A*pow(D, m, p) % p == 1
x = pow(a, (t + 1)//2, p)*pow(D, m//2, p) % p
return x
def sqrt_mod(a, p, all_roots=False):
"""
Find a root of ``x**2 = a mod p``.
Parameters
==========
a : integer
p : positive integer
all_roots : if True the list of roots is returned or None
Notes
=====
If there is no root it is returned None; else the returned root
is less or equal to ``p // 2``; in general is not the smallest one.
It is returned ``p // 2`` only if it is the only root.
Use ``all_roots`` only when it is expected that all the roots fit
in memory; otherwise use ``sqrt_mod_iter``.
Examples
========
>>> from sympy.ntheory import sqrt_mod
>>> sqrt_mod(11, 43)
21
>>> sqrt_mod(17, 32, True)
[7, 9, 23, 25]
"""
if all_roots:
return sorted(sqrt_mod_iter(a, p))
p = abs(as_int(p))
halfp = p // 2
x = None
for r in sqrt_mod_iter(a, p):
if r < halfp:
return r
elif r > halfp:
return p - r
else:
x = r
return x
def sqrt_mod_iter(a, p, domain=int):
"""
Iterate over solutions to ``x**2 = a mod p``.
Parameters
==========
a : integer
p : positive integer
domain : integer domain, ``int``, ``ZZ`` or ``Integer``
Examples
========
>>> from sympy.ntheory.residue_ntheory import sqrt_mod_iter
>>> list(sqrt_mod_iter(11, 43))
[21, 22]
See Also
========
sqrt_mod : Same functionality, but you want a sorted list or only one solution.
"""
a, p = as_int(a), abs(as_int(p))
v = []
pv = []
_product = product
for px, ex in factorint(p).items():
if a % px:
# `len(rx)` is at most 4
rx = _sqrt_mod_prime_power(a, px, ex)
else:
# `len(list(rx))` can be assumed to be large.
# The `itertools.product` is disadvantageous in terms of memory usage.
# It is also inferior to iproduct in speed if not all Cartesian products are needed.
rx = _sqrt_mod1(a, px, ex)
_product = iproduct
if not rx:
return
v.append(rx)
pv.append(px**ex)
if len(v) == 1:
yield from map(domain, v[0])
else:
mm, e, s = gf_crt1(pv, ZZ)
for vx in _product(*v):
yield domain(gf_crt2(vx, pv, mm, e, s, ZZ))
def _sqrt_mod_prime_power(a, p, k):
"""
Find the solutions to ``x**2 = a mod p**k`` when ``a % p != 0``.
If no solution exists, return ``None``.
Solutions are returned in an ascending list.
Parameters
==========
a : integer
p : prime number
k : positive integer
Examples
========
>>> from sympy.ntheory.residue_ntheory import _sqrt_mod_prime_power
>>> _sqrt_mod_prime_power(11, 43, 1)
[21, 22]
References
==========
.. [1] P. Hackman "Elementary Number Theory" (2009), page 160
.. [2] http://www.numbertheory.org/php/squareroot.html
.. [3] [Gathen99]_
"""
pk = p**k
a = a % pk
if p == 2:
# see Ref.[2]
if a % 8 != 1:
return None
# Trivial
if k <= 3:
return list(range(1, pk, 2))
r = 1
# r is one of the solutions to x**2 - a = 0 (mod 2**3).
# Hensel lift them to solutions of x**2 - a = 0 (mod 2**k)
# if r**2 - a = 0 mod 2**nx but not mod 2**(nx+1)
# then r + 2**(nx - 1) is a root mod 2**(nx+1)
for nx in range(3, k):
if ((r**2 - a) >> nx) % 2:
r += 1 << (nx - 1)
# r is a solution of x**2 - a = 0 (mod 2**k), and
# there exist other solutions -r, r+h, -(r+h), and these are all solutions.
h = 1 << (k - 1)
return sorted([r, pk - r, (r + h) % pk, -(r + h) % pk])
# If the Legendre symbol (a/p) is not 1, no solution exists.
if jacobi(a, p) != 1:
return None
if p % 4 == 3:
res = pow(a, (p + 1) // 4, p)
elif p % 8 == 5:
res = pow(a, (p + 3) // 8, p)
if pow(res, 2, p) != a % p:
res = res * pow(2, (p - 1) // 4, p) % p
else:
res = _sqrt_mod_tonelli_shanks(a, p)
if k > 1:
# Hensel lifting with Newton iteration, see Ref.[3] chapter 9
# with f(x) = x**2 - a; one has f'(a) != 0 (mod p) for p != 2
px = p
for _ in range(k.bit_length() - 1):
px = px**2
frinv = invert(2*res, px)
res = (res - (res**2 - a)*frinv) % px
if k & (k - 1): # If k is not a power of 2
frinv = invert(2*res, pk)
res = (res - (res**2 - a)*frinv) % pk
return sorted([res, pk - res])
def _sqrt_mod1(a, p, n):
"""
Find solution to ``x**2 == a mod p**n`` when ``a % p == 0``.
If no solution exists, return ``None``.
Parameters
==========
a : integer
p : prime number, p must divide a
n : positive integer
References
==========
.. [1] http://www.numbertheory.org/php/squareroot.html
"""
pn = p**n
a = a % pn
if a == 0:
# case gcd(a, p**k) = p**n
return range(0, pn, p**((n + 1) // 2))
# case gcd(a, p**k) = p**r, r < n
a, r = remove(a, p)
if r % 2 == 1:
return None
res = _sqrt_mod_prime_power(a, p, n - r)
if res is None:
return None
m = r // 2
return (x for rx in res for x in range(rx*p**m, pn, p**(n - m)))
def is_quad_residue(a, p):
"""
Returns True if ``a`` (mod ``p``) is in the set of squares mod ``p``,
i.e a % p in set([i**2 % p for i in range(p)]).
Parameters
==========
a : integer
p : positive integer
Returns
=======
bool : If True, ``x**2 == a (mod p)`` has solution.
Raises
======
ValueError
If ``a``, ``p`` is not integer.
If ``p`` is not positive.
Examples
========
>>> from sympy.ntheory import is_quad_residue
>>> is_quad_residue(21, 100)
True
Indeed, ``pow(39, 2, 100)`` would be 21.
>>> is_quad_residue(21, 120)
False
That is, for any integer ``x``, ``pow(x, 2, 120)`` is not 21.
If ``p`` is an odd
prime, an iterative method is used to make the determination:
>>> from sympy.ntheory import is_quad_residue
>>> sorted(set([i**2 % 7 for i in range(7)]))
[0, 1, 2, 4]
>>> [j for j in range(7) if is_quad_residue(j, 7)]
[0, 1, 2, 4]
See Also
========
legendre_symbol, jacobi_symbol, sqrt_mod
"""
a, p = as_int(a), as_int(p)
if p < 1:
raise ValueError('p must be > 0')
a %= p
if a < 2 or p < 3:
return True
# Since we want to compute the Jacobi symbol,
# we separate p into the odd part and the rest.
t = bit_scan1(p)
if t:
# The existence of a solution to a power of 2 is determined
# using the logic of `p==2` in `_sqrt_mod_prime_power` and `_sqrt_mod1`.
a_ = a % (1 << t)
if a_:
r = bit_scan1(a_)
if r % 2 or (a_ >> r) & 6:
return False
p >>= t
a %= p
if a < 2 or p < 3:
return True
# If Jacobi symbol is -1 or p is prime, can be determined by Jacobi symbol only
j = jacobi(a, p)
if j == -1 or isprime(p):
return j == 1
# Checks if `x**2 = a (mod p)` has a solution
for px, ex in factorint(p).items():
if a % px:
if jacobi(a, px) != 1:
return False
else:
a_ = a % px**ex
if a_ == 0:
continue
a_, r = remove(a_, px)
if r % 2 or jacobi(a_, px) != 1:
return False
return True
def is_nthpow_residue(a, n, m):
"""
Returns True if ``x**n == a (mod m)`` has solutions.
References
==========
.. [1] P. Hackman "Elementary Number Theory" (2009), page 76
"""
a = a % m
a, n, m = as_int(a), as_int(n), as_int(m)
if m <= 0:
raise ValueError('m must be > 0')
if n < 0:
raise ValueError('n must be >= 0')
if n == 0:
if m == 1:
return False
return a == 1
if a == 0:
return True
if n == 1:
return True
if n == 2:
return is_quad_residue(a, m)
return all(_is_nthpow_residue_bign_prime_power(a, n, p, e)
for p, e in factorint(m).items())
def _is_nthpow_residue_bign_prime_power(a, n, p, k):
r"""
Returns True if `x^n = a \pmod{p^k}` has solutions for `n > 2`.
Parameters
==========
a : positive integer
n : integer, n > 2
p : prime number
k : positive integer
"""
while a % p == 0:
a %= pow(p, k)
if not a:
return True
a, mu = remove(a, p)
if mu % n:
return False
k -= mu
if p != 2:
f = p**(k - 1)*(p - 1) # f = totient(p**k)
return pow(a, f // gcd(f, n), pow(p, k)) == 1
if n & 1:
return True
c = min(bit_scan1(n) + 2, k)
return a % pow(2, c) == 1
def _nthroot_mod1(s, q, p, all_roots):
"""
Root of ``x**q = s mod p``, ``p`` prime and ``q`` divides ``p - 1``.
Assume that the root exists.
Parameters
==========
s : integer
q : integer, n > 2. ``q`` divides ``p - 1``.
p : prime number
all_roots : if False returns the smallest root, else the list of roots
Returns
=======
list[int] | int :
Root of ``x**q = s mod p``. If ``all_roots == True``,
returned ascending list. otherwise, returned an int.
Examples
========
>>> from sympy.ntheory.residue_ntheory import _nthroot_mod1
>>> _nthroot_mod1(5, 3, 13, False)
7
>>> _nthroot_mod1(13, 4, 17, True)
[3, 5, 12, 14]
References
==========
.. [1] A. M. Johnston, A Generalized qth Root Algorithm,
ACM-SIAM Symposium on Discrete Algorithms (1999), pp. 929-930
"""
g = next(_primitive_root_prime_iter(p))
r = s
for qx, ex in factorint(q).items():
f = (p - 1) // qx**ex
while f % qx == 0:
f //= qx
z = f*invert(-f, qx)
x = (1 + z) // qx
t = discrete_log(p, pow(r, f, p), pow(g, f*qx, p))
for _ in range(ex):
# assert t == discrete_log(p, pow(r, f, p), pow(g, f*qx, p))
r = pow(r, x, p)*pow(g, -z*t % (p - 1), p) % p
t //= qx
res = [r]
h = pow(g, (p - 1) // q, p)
#assert pow(h, q, p) == 1
hx = r
for _ in range(q - 1):
hx = (hx*h) % p
res.append(hx)
if all_roots:
res.sort()
return res
return min(res)
def _nthroot_mod_prime_power(a, n, p, k):
""" Root of ``x**n = a mod p**k``.
Parameters
==========
a : integer
n : integer, n > 2
p : prime number
k : positive integer
Returns
=======
list[int] :
Ascending list of roots of ``x**n = a mod p**k``.
If no solution exists, return ``[]``.
"""
if not _is_nthpow_residue_bign_prime_power(a, n, p, k):
return []
a_mod_p = a % p
if a_mod_p == 0:
base_roots = [0]
elif (p - 1) % n == 0:
base_roots = _nthroot_mod1(a_mod_p, n, p, all_roots=True)
else:
# The roots of ``x**n - a = 0 (mod p)`` are roots of
# ``gcd(x**n - a, x**(p - 1) - 1) = 0 (mod p)``
pa = n
pb = p - 1
b = 1
if pa < pb:
a_mod_p, pa, b, pb = b, pb, a_mod_p, pa
# gcd(x**pa - a, x**pb - b) = gcd(x**pb - b, x**pc - c)
# where pc = pa % pb; c = b**-q * a mod p
while pb:
q, pc = divmod(pa, pb)
c = pow(b, -q, p) * a_mod_p % p
pa, pb = pb, pc
a_mod_p, b = b, c
if pa == 1:
base_roots = [a_mod_p]
elif pa == 2:
base_roots = sqrt_mod(a_mod_p, p, all_roots=True)
else:
base_roots = _nthroot_mod1(a_mod_p, pa, p, all_roots=True)
if k == 1:
return base_roots
a %= p**k
tot_roots = set()
for root in base_roots:
diff = pow(root, n - 1, p)*n % p
new_base = p
if diff != 0:
m_inv = invert(diff, p)
for _ in range(k - 1):
new_base *= p
tmp = pow(root, n, new_base) - a
tmp *= m_inv
root = (root - tmp) % new_base
tot_roots.add(root)
else:
roots_in_base = {root}
for _ in range(k - 1):
new_base *= p
new_roots = set()
for k_ in roots_in_base:
if pow(k_, n, new_base) != a % new_base:
continue
while k_ not in new_roots:
new_roots.add(k_)
k_ = (k_ + (new_base // p)) % new_base
roots_in_base = new_roots
tot_roots = tot_roots | roots_in_base
return sorted(tot_roots)
def nthroot_mod(a, n, p, all_roots=False):
"""
Find the solutions to ``x**n = a mod p``.
Parameters
==========
a : integer
n : positive integer
p : positive integer
all_roots : if False returns the smallest root, else the list of roots
Returns
=======
list[int] | int | None :
solutions to ``x**n = a mod p``.
The table of the output type is:
========== ========== ==========
all_roots has roots Returns
========== ========== ==========
True Yes list[int]
True No []
False Yes int
False No None
========== ========== ==========
Raises
======
ValueError
If ``a``, ``n`` or ``p`` is not integer.
If ``n`` or ``p`` is not positive.
Examples
========
>>> from sympy.ntheory.residue_ntheory import nthroot_mod
>>> nthroot_mod(11, 4, 19)
8
>>> nthroot_mod(11, 4, 19, True)
[8, 11]
>>> nthroot_mod(68, 3, 109)
23
References
==========
.. [1] P. Hackman "Elementary Number Theory" (2009), page 76
"""
a = a % p
a, n, p = as_int(a), as_int(n), as_int(p)
if n < 1:
raise ValueError("n should be positive")
if p < 1:
raise ValueError("p should be positive")
if n == 1:
return [a] if all_roots else a
if n == 2:
return sqrt_mod(a, p, all_roots)
base = []
prime_power = []
for q, e in factorint(p).items():
tot_roots = _nthroot_mod_prime_power(a, n, q, e)
if not tot_roots:
return [] if all_roots else None
prime_power.append(q**e)
base.append(sorted(tot_roots))
P, E, S = gf_crt1(prime_power, ZZ)
ret = sorted(map(int, {gf_crt2(c, prime_power, P, E, S, ZZ)
for c in product(*base)}))
if all_roots:
return ret
if ret:
return ret[0]
def quadratic_residues(p) -> list[int]:
"""
Returns the list of quadratic residues.
Examples
========
>>> from sympy.ntheory.residue_ntheory import quadratic_residues
>>> quadratic_residues(7)
[0, 1, 2, 4]
"""
p = as_int(p)
r = {pow(i, 2, p) for i in range(p // 2 + 1)}
return sorted(r)
@deprecated("""\
The `sympy.ntheory.residue_ntheory.legendre_symbol` has been moved to `sympy.functions.combinatorial.numbers.legendre_symbol`.""",
deprecated_since_version="1.13",
active_deprecations_target='deprecated-ntheory-symbolic-functions')
def legendre_symbol(a, p):
r"""
Returns the Legendre symbol `(a / p)`.
.. deprecated:: 1.13
The ``legendre_symbol`` function is deprecated. Use :class:`sympy.functions.combinatorial.numbers.legendre_symbol`
instead. See its documentation for more information. See
:ref:`deprecated-ntheory-symbolic-functions` for details.
For an integer ``a`` and an odd prime ``p``, the Legendre symbol is
defined as
.. math ::
\genfrac(){}{}{a}{p} = \begin{cases}
0 & \text{if } p \text{ divides } a\\
1 & \text{if } a \text{ is a quadratic residue modulo } p\\
-1 & \text{if } a \text{ is a quadratic nonresidue modulo } p
\end{cases}
Parameters
==========
a : integer
p : odd prime
Examples
========
>>> from sympy.functions.combinatorial.numbers import legendre_symbol
>>> [legendre_symbol(i, 7) for i in range(7)]
[0, 1, 1, -1, 1, -1, -1]
>>> sorted(set([i**2 % 7 for i in range(7)]))
[0, 1, 2, 4]
See Also
========
is_quad_residue, jacobi_symbol
"""
from sympy.functions.combinatorial.numbers import legendre_symbol as _legendre_symbol
return _legendre_symbol(a, p)
@deprecated("""\
The `sympy.ntheory.residue_ntheory.jacobi_symbol` has been moved to `sympy.functions.combinatorial.numbers.jacobi_symbol`.""",
deprecated_since_version="1.13",
active_deprecations_target='deprecated-ntheory-symbolic-functions')
def jacobi_symbol(m, n):
r"""
Returns the Jacobi symbol `(m / n)`.
.. deprecated:: 1.13
The ``jacobi_symbol`` function is deprecated. Use :class:`sympy.functions.combinatorial.numbers.jacobi_symbol`
instead. See its documentation for more information. See
:ref:`deprecated-ntheory-symbolic-functions` for details.
For any integer ``m`` and any positive odd integer ``n`` the Jacobi symbol
is defined as the product of the Legendre symbols corresponding to the
prime factors of ``n``:
.. math ::
\genfrac(){}{}{m}{n} =
\genfrac(){}{}{m}{p^{1}}^{\alpha_1}
\genfrac(){}{}{m}{p^{2}}^{\alpha_2}
...
\genfrac(){}{}{m}{p^{k}}^{\alpha_k}
\text{ where } n =
p_1^{\alpha_1}
p_2^{\alpha_2}
...
p_k^{\alpha_k}
Like the Legendre symbol, if the Jacobi symbol `\genfrac(){}{}{m}{n} = -1`
then ``m`` is a quadratic nonresidue modulo ``n``.
But, unlike the Legendre symbol, if the Jacobi symbol
`\genfrac(){}{}{m}{n} = 1` then ``m`` may or may not be a quadratic residue
modulo ``n``.
Parameters
==========
m : integer
n : odd positive integer
Examples
========
>>> from sympy.functions.combinatorial.numbers import jacobi_symbol, legendre_symbol
>>> from sympy import S
>>> jacobi_symbol(45, 77)
-1
>>> jacobi_symbol(60, 121)
1
The relationship between the ``jacobi_symbol`` and ``legendre_symbol`` can
be demonstrated as follows:
>>> L = legendre_symbol
>>> S(45).factors()
{3: 2, 5: 1}
>>> jacobi_symbol(7, 45) == L(7, 3)**2 * L(7, 5)**1
True
See Also
========
is_quad_residue, legendre_symbol
"""
from sympy.functions.combinatorial.numbers import jacobi_symbol as _jacobi_symbol
return _jacobi_symbol(m, n)
@deprecated("""\
The `sympy.ntheory.residue_ntheory.mobius` has been moved to `sympy.functions.combinatorial.numbers.mobius`.""",
deprecated_since_version="1.13",
active_deprecations_target='deprecated-ntheory-symbolic-functions')
def mobius(n):
"""
Mobius function maps natural number to {-1, 0, 1}
.. deprecated:: 1.13
The ``mobius`` function is deprecated. Use :class:`sympy.functions.combinatorial.numbers.mobius`
instead. See its documentation for more information. See
:ref:`deprecated-ntheory-symbolic-functions` for details.
It is defined as follows:
1) `1` if `n = 1`.
2) `0` if `n` has a squared prime factor.
3) `(-1)^k` if `n` is a square-free positive integer with `k`
number of prime factors.
It is an important multiplicative function in number theory
and combinatorics. It has applications in mathematical series,
algebraic number theory and also physics (Fermion operator has very
concrete realization with Mobius Function model).
Parameters
==========
n : positive integer
Examples
========
>>> from sympy.functions.combinatorial.numbers import mobius
>>> mobius(13*7)
1
>>> mobius(1)
1
>>> mobius(13*7*5)
-1
>>> mobius(13**2)
0
References
==========
.. [1] https://en.wikipedia.org/wiki/M%C3%B6bius_function
.. [2] Thomas Koshy "Elementary Number Theory with Applications"
"""
from sympy.functions.combinatorial.numbers import mobius as _mobius
return _mobius(n)
def _discrete_log_trial_mul(n, a, b, order=None):
"""
Trial multiplication algorithm for computing the discrete logarithm of
``a`` to the base ``b`` modulo ``n``.
The algorithm finds the discrete logarithm using exhaustive search. This
naive method is used as fallback algorithm of ``discrete_log`` when the
group order is very small.
Examples
========
>>> from sympy.ntheory.residue_ntheory import _discrete_log_trial_mul
>>> _discrete_log_trial_mul(41, 15, 7)
3
See Also
========
discrete_log
References
==========
.. [1] "Handbook of applied cryptography", Menezes, A. J., Van, O. P. C., &
Vanstone, S. A. (1997).
"""
a %= n
b %= n
if order is None:
order = n
x = 1
for i in range(order):
if x == a:
return i
x = x * b % n
raise ValueError("Log does not exist")
def _discrete_log_shanks_steps(n, a, b, order=None):
"""
Baby-step giant-step algorithm for computing the discrete logarithm of
``a`` to the base ``b`` modulo ``n``.
The algorithm is a time-memory trade-off of the method of exhaustive
search. It uses `O(sqrt(m))` memory, where `m` is the group order.
Examples
========
>>> from sympy.ntheory.residue_ntheory import _discrete_log_shanks_steps
>>> _discrete_log_shanks_steps(41, 15, 7)
3
See Also
========
discrete_log
References
==========
.. [1] "Handbook of applied cryptography", Menezes, A. J., Van, O. P. C., &
Vanstone, S. A. (1997).
"""
a %= n
b %= n
if order is None:
order = n_order(b, n)
m = sqrt(order) + 1
T = {}
x = 1
for i in range(m):
T[x] = i
x = x * b % n
z = pow(b, -m, n)
x = a
for i in range(m):
if x in T:
return i * m + T[x]
x = x * z % n
raise ValueError("Log does not exist")
def _discrete_log_pollard_rho(n, a, b, order=None, retries=10, rseed=None):
"""
Pollard's Rho algorithm for computing the discrete logarithm of ``a`` to
the base ``b`` modulo ``n``.
It is a randomized algorithm with the same expected running time as
``_discrete_log_shanks_steps``, but requires a negligible amount of memory.
Examples
========
>>> from sympy.ntheory.residue_ntheory import _discrete_log_pollard_rho
>>> _discrete_log_pollard_rho(227, 3**7, 3)
7
See Also
========
discrete_log
References
==========
.. [1] "Handbook of applied cryptography", Menezes, A. J., Van, O. P. C., &
Vanstone, S. A. (1997).
"""
a %= n
b %= n
if order is None:
order = n_order(b, n)
randint = _randint(rseed)
for i in range(retries):
aa = randint(1, order - 1)
ba = randint(1, order - 1)
xa = pow(b, aa, n) * pow(a, ba, n) % n
c = xa % 3
if c == 0:
xb = a * xa % n
ab = aa
bb = (ba + 1) % order
elif c == 1:
xb = xa * xa % n
ab = (aa + aa) % order
bb = (ba + ba) % order
else:
xb = b * xa % n
ab = (aa + 1) % order
bb = ba
for j in range(order):
c = xa % 3
if c == 0:
xa = a * xa % n
ba = (ba + 1) % order
elif c == 1:
xa = xa * xa % n
aa = (aa + aa) % order
ba = (ba + ba) % order
else:
xa = b * xa % n
aa = (aa + 1) % order
c = xb % 3
if c == 0:
xb = a * xb % n
bb = (bb + 1) % order
elif c == 1:
xb = xb * xb % n
ab = (ab + ab) % order
bb = (bb + bb) % order
else:
xb = b * xb % n
ab = (ab + 1) % order
c = xb % 3
if c == 0:
xb = a * xb % n
bb = (bb + 1) % order
elif c == 1:
xb = xb * xb % n
ab = (ab + ab) % order
bb = (bb + bb) % order
else:
xb = b * xb % n
ab = (ab + 1) % order
if xa == xb:
r = (ba - bb) % order
try:
e = invert(r, order) * (ab - aa) % order
if (pow(b, e, n) - a) % n == 0:
return e
except ZeroDivisionError:
pass
break
raise ValueError("Pollard's Rho failed to find logarithm")
def _discrete_log_is_smooth(n: int, factorbase: list):
"""Try to factor n with respect to a given factorbase.
Upon success a list of exponents with repect to the factorbase is returned.
Otherwise None."""
factors = [0]*len(factorbase)
for i, p in enumerate(factorbase):
while n % p == 0: # divide by p as many times as possible
factors[i] += 1
n = n // p
if n != 1:
return None # the number factors if at the end nothing is left
return factors
def _discrete_log_index_calculus(n, a, b, order, rseed=None):
"""
Index Calculus algorithm for computing the discrete logarithm of ``a`` to
the base ``b`` modulo ``n``.
The group order must be given and prime. It is not suitable for small orders
and the algorithm might fail to find a solution in such situations.
Examples
========
>>> from sympy.ntheory.residue_ntheory import _discrete_log_index_calculus
>>> _discrete_log_index_calculus(24570203447, 23859756228, 2, 12285101723)
4519867240
See Also
========
discrete_log
References
==========
.. [1] "Handbook of applied cryptography", Menezes, A. J., Van, O. P. C., &
Vanstone, S. A. (1997).
"""
randint = _randint(rseed)
from math import sqrt, exp, log
a %= n
b %= n
# assert isprime(order), "The order of the base must be prime."
# First choose a heuristic the bound B for the factorbase.
# We have added an extra term to the asymptotic value which
# is closer to the theoretical optimum for n up to 2^70.
B = int(exp(0.5 * sqrt( log(n) * log(log(n)) )*( 1 + 1/log(log(n)) )))
max = 5 * B * B # expected number of trys to find a relation
factorbase = list(primerange(B)) # compute the factorbase
lf = len(factorbase) # length of the factorbase
ordermo = order-1
abx = a
for x in range(order):
if abx == 1:
return (order - x) % order
relationa = _discrete_log_is_smooth(abx, factorbase)
if relationa:
relationa = [r % order for r in relationa] + [x]
break
abx = abx * b % n # abx = a*pow(b, x, n) % n
else:
raise ValueError("Index Calculus failed")
relations = [None] * lf
k = 1 # number of relations found
kk = 0
while k < 3 * lf and kk < max: # find relations for all primes in our factor base
x = randint(1,ordermo)
relation = _discrete_log_is_smooth(pow(b,x,n), factorbase)
if relation is None:
kk += 1
continue
k += 1
kk = 0
relation += [ x ]
index = lf # determine the index of the first nonzero entry
for i in range(lf):
ri = relation[i] % order
if ri> 0 and relations[i] is not None: # make this entry zero if we can
for j in range(lf+1):
relation[j] = (relation[j] - ri*relations[i][j]) % order
else:
relation[i] = ri
if relation[i] > 0 and index == lf: # is this the index of the first nonzero entry?
index = i
if index == lf or relations[index] is not None: # the relation contains no new information
continue
# the relation contains new information
rinv = pow(relation[index],-1,order) # normalize the first nonzero entry
for j in range(index,lf+1):
relation[j] = rinv * relation[j] % order
relations[index] = relation
for i in range(lf): # subtract the new relation from the one for a
if relationa[i] > 0 and relations[i] is not None:
rbi = relationa[i]
for j in range(lf+1):
relationa[j] = (relationa[j] - rbi*relations[i][j]) % order
if relationa[i] > 0: # the index of the first nonzero entry
break # we do not need to reduce further at this point
else: # all unkowns are gone
#print(f"Success after {k} relations out of {lf}")
x = (order -relationa[lf]) % order
if pow(b,x,n) == a:
return x
raise ValueError("Index Calculus failed")
raise ValueError("Index Calculus failed")
def _discrete_log_pohlig_hellman(n, a, b, order=None, order_factors=None):
"""
Pohlig-Hellman algorithm for computing the discrete logarithm of ``a`` to
the base ``b`` modulo ``n``.
In order to compute the discrete logarithm, the algorithm takes advantage
of the factorization of the group order. It is more efficient when the
group order factors into many small primes.
Examples
========
>>> from sympy.ntheory.residue_ntheory import _discrete_log_pohlig_hellman
>>> _discrete_log_pohlig_hellman(251, 210, 71)
197
See Also
========
discrete_log
References
==========
.. [1] "Handbook of applied cryptography", Menezes, A. J., Van, O. P. C., &
Vanstone, S. A. (1997).
"""
from .modular import crt
a %= n
b %= n
if order is None:
order = n_order(b, n)
if order_factors is None:
order_factors = factorint(order)
l = [0] * len(order_factors)
for i, (pi, ri) in enumerate(order_factors.items()):
for j in range(ri):
aj = pow(a * pow(b, -l[i], n), order // pi**(j + 1), n)
bj = pow(b, order // pi, n)
cj = discrete_log(n, aj, bj, pi, True)
l[i] += cj * pi**j
d, _ = crt([pi**ri for pi, ri in order_factors.items()], l)
return d
def discrete_log(n, a, b, order=None, prime_order=None):
"""
Compute the discrete logarithm of ``a`` to the base ``b`` modulo ``n``.
This is a recursive function to reduce the discrete logarithm problem in
cyclic groups of composite order to the problem in cyclic groups of prime
order.
It employs different algorithms depending on the problem (subgroup order
size, prime order or not):
* Trial multiplication
* Baby-step giant-step
* Pollard's Rho
* Index Calculus
* Pohlig-Hellman
Examples
========
>>> from sympy.ntheory import discrete_log
>>> discrete_log(41, 15, 7)
3
References
==========
.. [1] https://mathworld.wolfram.com/DiscreteLogarithm.html
.. [2] "Handbook of applied cryptography", Menezes, A. J., Van, O. P. C., &
Vanstone, S. A. (1997).
"""
from math import sqrt, log
n, a, b = as_int(n), as_int(a), as_int(b)
if order is None:
# Compute the order and its factoring in one pass
# order = totient(n), factors = factorint(order)
factors = {}
for px, kx in factorint(n).items():
if kx > 1:
if px in factors:
factors[px] += kx - 1
else:
factors[px] = kx - 1
for py, ky in factorint(px - 1).items():
if py in factors:
factors[py] += ky
else:
factors[py] = ky
order = 1
for px, kx in factors.items():
order *= px**kx
# Now the `order` is the order of the group and factors = factorint(order)
# The order of `b` divides the order of the group.
order_factors = {}
for p, e in factors.items():
i = 0
for _ in range(e):
if pow(b, order // p, n) == 1:
order //= p
i += 1
else:
break
if i < e:
order_factors[p] = e - i
if prime_order is None:
prime_order = isprime(order)
if order < 1000:
return _discrete_log_trial_mul(n, a, b, order)
elif prime_order:
# Shanks and Pollard rho are O(sqrt(order)) while index calculus is O(exp(2*sqrt(log(n)log(log(n)))))
# we compare the expected running times to determine the algorithmus which is expected to be faster
if 4*sqrt(log(n)*log(log(n))) < log(order) - 10: # the number 10 was determined experimental
return _discrete_log_index_calculus(n, a, b, order)
elif order < 1000000000000:
# Shanks seems typically faster, but uses O(sqrt(order)) memory
return _discrete_log_shanks_steps(n, a, b, order)
return _discrete_log_pollard_rho(n, a, b, order)
return _discrete_log_pohlig_hellman(n, a, b, order, order_factors)
def quadratic_congruence(a, b, c, n):
r"""
Find the solutions to `a x^2 + b x + c \equiv 0 \pmod{n}`.
Parameters
==========
a : int
b : int
c : int
n : int
A positive integer.
Returns
=======
list[int] :
A sorted list of solutions. If no solution exists, ``[]``.
Examples
========
>>> from sympy.ntheory.residue_ntheory import quadratic_congruence
>>> quadratic_congruence(2, 5, 3, 7) # 2x^2 + 5x + 3 = 0 (mod 7)
[2, 6]
>>> quadratic_congruence(8, 6, 4, 15) # No solution
[]
See Also
========
polynomial_congruence : Solve the polynomial congruence
"""
a = as_int(a)
b = as_int(b)
c = as_int(c)
n = as_int(n)
if n <= 1:
raise ValueError("n should be an integer greater than 1")
a %= n
b %= n
c %= n
if a == 0:
return linear_congruence(b, -c, n)
if n == 2:
# assert a == 1
roots = []
if c == 0:
roots.append(0)
if (b + c) % 2:
roots.append(1)
return roots
if gcd(2*a, n) == 1:
inv_a = invert(a, n)
b *= inv_a
c *= inv_a
if b % 2:
b += n
b >>= 1
return sorted((i - b) % n for i in sqrt_mod_iter(b**2 - c, n))
res = set()
for i in sqrt_mod_iter(b**2 - 4*a*c, 4*a*n):
res.update(j % n for j in linear_congruence(2*a, i - b, 4*a*n))
return sorted(res)
def _valid_expr(expr):
"""
return coefficients of expr if it is a univariate polynomial
with integer coefficients else raise a ValueError.
"""
if not expr.is_polynomial():
raise ValueError("The expression should be a polynomial")
polynomial = Poly(expr)
if not polynomial.is_univariate:
raise ValueError("The expression should be univariate")
if not polynomial.domain == ZZ:
raise ValueError("The expression should should have integer coefficients")
return polynomial.all_coeffs()
def polynomial_congruence(expr, m):
"""
Find the solutions to a polynomial congruence equation modulo m.
Parameters
==========
expr : integer coefficient polynomial
m : positive integer
Examples
========
>>> from sympy.ntheory import polynomial_congruence
>>> from sympy.abc import x
>>> expr = x**6 - 2*x**5 -35
>>> polynomial_congruence(expr, 6125)
[3257]
See Also
========
sympy.polys.galoistools.gf_csolve : low level solving routine used by this routine
"""
coefficients = _valid_expr(expr)
coefficients = [num % m for num in coefficients]
rank = len(coefficients)
if rank == 3:
return quadratic_congruence(*coefficients, m)
if rank == 2:
return quadratic_congruence(0, *coefficients, m)
if coefficients[0] == 1 and 1 + coefficients[-1] == sum(coefficients):
return nthroot_mod(-coefficients[-1], rank - 1, m, True)
return gf_csolve(coefficients, m)
def binomial_mod(n, m, k):
"""Compute ``binomial(n, m) % k``.
Explanation
===========
Returns ``binomial(n, m) % k`` using a generalization of Lucas'
Theorem for prime powers given by Granville [1]_, in conjunction with
the Chinese Remainder Theorem. The residue for each prime power
is calculated in time O(log^2(n) + q^4*log(n)log(p) + q^4*p*log^3(p)).
Parameters
==========
n : an integer
m : an integer
k : a positive integer
Examples
========
>>> from sympy.ntheory.residue_ntheory import binomial_mod
>>> binomial_mod(10, 2, 6) # binomial(10, 2) = 45
3
>>> binomial_mod(17, 9, 10) # binomial(17, 9) = 24310
0
References
==========
.. [1] Binomial coefficients modulo prime powers, Andrew Granville,
Available: https://web.archive.org/web/20170202003812/http://www.dms.umontreal.ca/~andrew/PDF/BinCoeff.pdf
"""
if k < 1: raise ValueError('k is required to be positive')
# We decompose q into a product of prime powers and apply
# the generalization of Lucas' Theorem given by Granville
# to obtain binomial(n, k) mod p^e, and then use the Chinese
# Remainder Theorem to obtain the result mod q
if n < 0 or m < 0 or m > n: return 0
factorisation = factorint(k)
residues = [_binomial_mod_prime_power(n, m, p, e) for p, e in factorisation.items()]
return crt([p**pw for p, pw in factorisation.items()], residues, check=False)[0]
def _binomial_mod_prime_power(n, m, p, q):
"""Compute ``binomial(n, m) % p**q`` for a prime ``p``.
Parameters
==========
n : positive integer
m : a nonnegative integer
p : a prime
q : a positive integer (the prime exponent)
Examples
========
>>> from sympy.ntheory.residue_ntheory import _binomial_mod_prime_power
>>> _binomial_mod_prime_power(10, 2, 3, 2) # binomial(10, 2) = 45
0
>>> _binomial_mod_prime_power(17, 9, 2, 4) # binomial(17, 9) = 24310
6
References
==========
.. [1] Binomial coefficients modulo prime powers, Andrew Granville,
Available: https://web.archive.org/web/20170202003812/http://www.dms.umontreal.ca/~andrew/PDF/BinCoeff.pdf
"""
# Function/variable naming within this function follows Ref.[1]
# n!_p will be used to denote the product of integers <= n not divisible by
# p, with binomial(n, m)_p the same as binomial(n, m), but defined using
# n!_p in place of n!
modulo = pow(p, q)
def up_factorial(u):
"""Compute (u*p)!_p modulo p^q."""
r = q // 2
fac = prod = 1
if r == 1 and p == 2 or 2*r + 1 in (p, p*p):
if q % 2 == 1: r += 1
modulo, div = pow(p, 2*r), pow(p, 2*r - q)
else:
modulo, div = pow(p, 2*r + 1), pow(p, (2*r + 1) - q)
for j in range(1, r + 1):
for mul in range((j - 1)*p + 1, j*p): # ignore jp itself
fac *= mul
fac %= modulo
bj_ = bj(u, j, r)
prod *= pow(fac, bj_, modulo)
prod %= modulo
if p == 2:
sm = u // 2
for j in range(1, r + 1): sm += j//2 * bj(u, j, r)
if sm % 2 == 1: prod *= -1
prod %= modulo//div
return prod % modulo
def bj(u, j, r):
"""Compute the exponent of (j*p)!_p in the calculation of (u*p)!_p."""
prod = u
for i in range(1, r + 1):
if i != j: prod *= u*u - i*i
for i in range(1, r + 1):
if i != j: prod //= j*j - i*i
return prod // j
def up_plus_v_binom(u, v):
"""Compute binomial(u*p + v, v)_p modulo p^q."""
prod = 1
div = invert(factorial(v), modulo)
for j in range(1, q):
b = div
for v_ in range(j*p + 1, j*p + v + 1):
b *= v_
b %= modulo
aj = u
for i in range(1, q):
if i != j: aj *= u - i
for i in range(1, q):
if i != j: aj //= j - i
aj //= j
prod *= pow(b, aj, modulo)
prod %= modulo
return prod
@recurrence_memo([1])
def factorial(v, prev):
"""Compute v! modulo p^q."""
return v*prev[-1] % modulo
def factorial_p(n):
"""Compute n!_p modulo p^q."""
u, v = divmod(n, p)
return (factorial(v) * up_factorial(u) * up_plus_v_binom(u, v)) % modulo
prod = 1
Nj, Mj, Rj = n, m, n - m
# e0 will be the p-adic valuation of binomial(n, m) at p
e0 = carry = eq_1 = j = 0
while Nj:
numerator = factorial_p(Nj % modulo)
denominator = factorial_p(Mj % modulo) * factorial_p(Rj % modulo) % modulo
Nj, (Mj, mj), (Rj, rj) = Nj//p, divmod(Mj, p), divmod(Rj, p)
carry = (mj + rj + carry) // p
e0 += carry
if j >= q - 1: eq_1 += carry
prod *= numerator * invert(denominator, modulo)
prod %= modulo
j += 1
mul = pow(1 if p == 2 and q >= 3 else -1, eq_1, modulo)
return (pow(p, e0, modulo) * mul * prod) % modulo
PK ]ZZZ��} } sympy/parsing/__init__.py"""Used for translating a string into a SymPy expression. """
__all__ = ['parse_expr']
from .sympy_parser import parse_expr
PK ]ZZZ����
�
sympy/parsing/ast_parser.py"""
This module implements the functionality to take any Python expression as a
string and fix all numbers and other things before evaluating it,
thus
1/2
returns
Integer(1)/Integer(2)
We use the ast module for this. It is well documented at docs.python.org.
Some tips to understand how this works: use dump() to get a nice
representation of any node. Then write a string of what you want to get,
e.g. "Integer(1)", parse it, dump it and you'll see that you need to do
"Call(Name('Integer', Load()), [node], [], None, None)". You do not need
to bother with lineno and col_offset, just call fix_missing_locations()
before returning the node.
"""
from sympy.core.basic import Basic
from sympy.core.sympify import SympifyError
from ast import parse, NodeTransformer, Call, Name, Load, \
fix_missing_locations, Constant, Tuple
class Transform(NodeTransformer):
def __init__(self, local_dict, global_dict):
NodeTransformer.__init__(self)
self.local_dict = local_dict
self.global_dict = global_dict
def visit_Constant(self, node):
if isinstance(node.value, int):
return fix_missing_locations(Call(func=Name('Integer', Load()),
args=[node], keywords=[]))
elif isinstance(node.value, float):
return fix_missing_locations(Call(func=Name('Float', Load()),
args=[node], keywords=[]))
return node
def visit_Name(self, node):
if node.id in self.local_dict:
return node
elif node.id in self.global_dict:
name_obj = self.global_dict[node.id]
if isinstance(name_obj, (Basic, type)) or callable(name_obj):
return node
elif node.id in ['True', 'False']:
return node
return fix_missing_locations(Call(func=Name('Symbol', Load()),
args=[Constant(node.id)], keywords=[]))
def visit_Lambda(self, node):
args = [self.visit(arg) for arg in node.args.args]
body = self.visit(node.body)
n = Call(func=Name('Lambda', Load()),
args=[Tuple(args, Load()), body], keywords=[])
return fix_missing_locations(n)
def parse_expr(s, local_dict):
"""
Converts the string "s" to a SymPy expression, in local_dict.
It converts all numbers to Integers before feeding it to Python and
automatically creates Symbols.
"""
global_dict = {}
exec('from sympy import *', global_dict)
try:
a = parse(s.strip(), mode="eval")
except SyntaxError:
raise SympifyError("Cannot parse %s." % repr(s))
a = Transform(local_dict, global_dict).visit(a)
e = compile(a, "<string>", "eval")
return eval(e, global_dict, local_dict)
PK ]ZZZ&Ӥrۚ ۚ sympy/parsing/mathematica.pyfrom __future__ import annotations
import re
import typing
from itertools import product
from typing import Any, Callable
import sympy
from sympy import Mul, Add, Pow, Rational, log, exp, sqrt, cos, sin, tan, asin, acos, acot, asec, acsc, sinh, cosh, tanh, asinh, \
acosh, atanh, acoth, asech, acsch, expand, im, flatten, polylog, cancel, expand_trig, sign, simplify, \
UnevaluatedExpr, S, atan, atan2, Mod, Max, Min, rf, Ei, Si, Ci, airyai, airyaiprime, airybi, primepi, prime, \
isprime, cot, sec, csc, csch, sech, coth, Function, I, pi, Tuple, GreaterThan, StrictGreaterThan, StrictLessThan, \
LessThan, Equality, Or, And, Lambda, Integer, Dummy, symbols
from sympy.core.sympify import sympify, _sympify
from sympy.functions.special.bessel import airybiprime
from sympy.functions.special.error_functions import li
from sympy.utilities.exceptions import sympy_deprecation_warning
def mathematica(s, additional_translations=None):
sympy_deprecation_warning(
"""The ``mathematica`` function for the Mathematica parser is now
deprecated. Use ``parse_mathematica`` instead.
The parameter ``additional_translation`` can be replaced by SymPy's
.replace( ) or .subs( ) methods on the output expression instead.""",
deprecated_since_version="1.11",
active_deprecations_target="mathematica-parser-new",
)
parser = MathematicaParser(additional_translations)
return sympify(parser._parse_old(s))
def parse_mathematica(s):
"""
Translate a string containing a Wolfram Mathematica expression to a SymPy
expression.
If the translator is unable to find a suitable SymPy expression, the
``FullForm`` of the Mathematica expression will be output, using SymPy
``Function`` objects as nodes of the syntax tree.
Examples
========
>>> from sympy.parsing.mathematica import parse_mathematica
>>> parse_mathematica("Sin[x]^2 Tan[y]")
sin(x)**2*tan(y)
>>> e = parse_mathematica("F[7,5,3]")
>>> e
F(7, 5, 3)
>>> from sympy import Function, Max, Min
>>> e.replace(Function("F"), lambda *x: Max(*x)*Min(*x))
21
Both standard input form and Mathematica full form are supported:
>>> parse_mathematica("x*(a + b)")
x*(a + b)
>>> parse_mathematica("Times[x, Plus[a, b]]")
x*(a + b)
To get a matrix from Wolfram's code:
>>> m = parse_mathematica("{{a, b}, {c, d}}")
>>> m
((a, b), (c, d))
>>> from sympy import Matrix
>>> Matrix(m)
Matrix([
[a, b],
[c, d]])
If the translation into equivalent SymPy expressions fails, an SymPy
expression equivalent to Wolfram Mathematica's "FullForm" will be created:
>>> parse_mathematica("x_.")
Optional(Pattern(x, Blank()))
>>> parse_mathematica("Plus @@ {x, y, z}")
Apply(Plus, (x, y, z))
>>> parse_mathematica("f[x_, 3] := x^3 /; x > 0")
SetDelayed(f(Pattern(x, Blank()), 3), Condition(x**3, x > 0))
"""
parser = MathematicaParser()
return parser.parse(s)
def _parse_Function(*args):
if len(args) == 1:
arg = args[0]
Slot = Function("Slot")
slots = arg.atoms(Slot)
numbers = [a.args[0] for a in slots]
number_of_arguments = max(numbers)
if isinstance(number_of_arguments, Integer):
variables = symbols(f"dummy0:{number_of_arguments}", cls=Dummy)
return Lambda(variables, arg.xreplace({Slot(i+1): v for i, v in enumerate(variables)}))
return Lambda((), arg)
elif len(args) == 2:
variables = args[0]
body = args[1]
return Lambda(variables, body)
else:
raise SyntaxError("Function node expects 1 or 2 arguments")
def _deco(cls):
cls._initialize_class()
return cls
@_deco
class MathematicaParser:
"""
An instance of this class converts a string of a Wolfram Mathematica
expression to a SymPy expression.
The main parser acts internally in three stages:
1. tokenizer: tokenizes the Mathematica expression and adds the missing *
operators. Handled by ``_from_mathematica_to_tokens(...)``
2. full form list: sort the list of strings output by the tokenizer into a
syntax tree of nested lists and strings, equivalent to Mathematica's
``FullForm`` expression output. This is handled by the function
``_from_tokens_to_fullformlist(...)``.
3. SymPy expression: the syntax tree expressed as full form list is visited
and the nodes with equivalent classes in SymPy are replaced. Unknown
syntax tree nodes are cast to SymPy ``Function`` objects. This is
handled by ``_from_fullformlist_to_sympy(...)``.
"""
# left: Mathematica, right: SymPy
CORRESPONDENCES = {
'Sqrt[x]': 'sqrt(x)',
'Rational[x,y]': 'Rational(x,y)',
'Exp[x]': 'exp(x)',
'Log[x]': 'log(x)',
'Log[x,y]': 'log(y,x)',
'Log2[x]': 'log(x,2)',
'Log10[x]': 'log(x,10)',
'Mod[x,y]': 'Mod(x,y)',
'Max[*x]': 'Max(*x)',
'Min[*x]': 'Min(*x)',
'Pochhammer[x,y]':'rf(x,y)',
'ArcTan[x,y]':'atan2(y,x)',
'ExpIntegralEi[x]': 'Ei(x)',
'SinIntegral[x]': 'Si(x)',
'CosIntegral[x]': 'Ci(x)',
'AiryAi[x]': 'airyai(x)',
'AiryAiPrime[x]': 'airyaiprime(x)',
'AiryBi[x]' :'airybi(x)',
'AiryBiPrime[x]' :'airybiprime(x)',
'LogIntegral[x]':' li(x)',
'PrimePi[x]': 'primepi(x)',
'Prime[x]': 'prime(x)',
'PrimeQ[x]': 'isprime(x)'
}
# trigonometric, e.t.c.
for arc, tri, h in product(('', 'Arc'), (
'Sin', 'Cos', 'Tan', 'Cot', 'Sec', 'Csc'), ('', 'h')):
fm = arc + tri + h + '[x]'
if arc: # arc func
fs = 'a' + tri.lower() + h + '(x)'
else: # non-arc func
fs = tri.lower() + h + '(x)'
CORRESPONDENCES.update({fm: fs})
REPLACEMENTS = {
' ': '',
'^': '**',
'{': '[',
'}': ']',
}
RULES = {
# a single whitespace to '*'
'whitespace': (
re.compile(r'''
(?:(?<=[a-zA-Z\d])|(?<=\d\.)) # a letter or a number
\s+ # any number of whitespaces
(?:(?=[a-zA-Z\d])|(?=\.\d)) # a letter or a number
''', re.VERBOSE),
'*'),
# add omitted '*' character
'add*_1': (
re.compile(r'''
(?:(?<=[])\d])|(?<=\d\.)) # ], ) or a number
# ''
(?=[(a-zA-Z]) # ( or a single letter
''', re.VERBOSE),
'*'),
# add omitted '*' character (variable letter preceding)
'add*_2': (
re.compile(r'''
(?<=[a-zA-Z]) # a letter
\( # ( as a character
(?=.) # any characters
''', re.VERBOSE),
'*('),
# convert 'Pi' to 'pi'
'Pi': (
re.compile(r'''
(?:
\A|(?<=[^a-zA-Z])
)
Pi # 'Pi' is 3.14159... in Mathematica
(?=[^a-zA-Z])
''', re.VERBOSE),
'pi'),
}
# Mathematica function name pattern
FM_PATTERN = re.compile(r'''
(?:
\A|(?<=[^a-zA-Z]) # at the top or a non-letter
)
[A-Z][a-zA-Z\d]* # Function
(?=\[) # [ as a character
''', re.VERBOSE)
# list or matrix pattern (for future usage)
ARG_MTRX_PATTERN = re.compile(r'''
\{.*\}
''', re.VERBOSE)
# regex string for function argument pattern
ARGS_PATTERN_TEMPLATE = r'''
(?:
\A|(?<=[^a-zA-Z])
)
{arguments} # model argument like x, y,...
(?=[^a-zA-Z])
'''
# will contain transformed CORRESPONDENCES dictionary
TRANSLATIONS: dict[tuple[str, int], dict[str, Any]] = {}
# cache for a raw users' translation dictionary
cache_original: dict[tuple[str, int], dict[str, Any]] = {}
# cache for a compiled users' translation dictionary
cache_compiled: dict[tuple[str, int], dict[str, Any]] = {}
@classmethod
def _initialize_class(cls):
# get a transformed CORRESPONDENCES dictionary
d = cls._compile_dictionary(cls.CORRESPONDENCES)
cls.TRANSLATIONS.update(d)
def __init__(self, additional_translations=None):
self.translations = {}
# update with TRANSLATIONS (class constant)
self.translations.update(self.TRANSLATIONS)
if additional_translations is None:
additional_translations = {}
# check the latest added translations
if self.__class__.cache_original != additional_translations:
if not isinstance(additional_translations, dict):
raise ValueError('The argument must be dict type')
# get a transformed additional_translations dictionary
d = self._compile_dictionary(additional_translations)
# update cache
self.__class__.cache_original = additional_translations
self.__class__.cache_compiled = d
# merge user's own translations
self.translations.update(self.__class__.cache_compiled)
@classmethod
def _compile_dictionary(cls, dic):
# for return
d = {}
for fm, fs in dic.items():
# check function form
cls._check_input(fm)
cls._check_input(fs)
# uncover '*' hiding behind a whitespace
fm = cls._apply_rules(fm, 'whitespace')
fs = cls._apply_rules(fs, 'whitespace')
# remove whitespace(s)
fm = cls._replace(fm, ' ')
fs = cls._replace(fs, ' ')
# search Mathematica function name
m = cls.FM_PATTERN.search(fm)
# if no-hit
if m is None:
err = "'{f}' function form is invalid.".format(f=fm)
raise ValueError(err)
# get Mathematica function name like 'Log'
fm_name = m.group()
# get arguments of Mathematica function
args, end = cls._get_args(m)
# function side check. (e.g.) '2*Func[x]' is invalid.
if m.start() != 0 or end != len(fm):
err = "'{f}' function form is invalid.".format(f=fm)
raise ValueError(err)
# check the last argument's 1st character
if args[-1][0] == '*':
key_arg = '*'
else:
key_arg = len(args)
key = (fm_name, key_arg)
# convert '*x' to '\\*x' for regex
re_args = [x if x[0] != '*' else '\\' + x for x in args]
# for regex. Example: (?:(x|y|z))
xyz = '(?:(' + '|'.join(re_args) + '))'
# string for regex compile
patStr = cls.ARGS_PATTERN_TEMPLATE.format(arguments=xyz)
pat = re.compile(patStr, re.VERBOSE)
# update dictionary
d[key] = {}
d[key]['fs'] = fs # SymPy function template
d[key]['args'] = args # args are ['x', 'y'] for example
d[key]['pat'] = pat
return d
def _convert_function(self, s):
'''Parse Mathematica function to SymPy one'''
# compiled regex object
pat = self.FM_PATTERN
scanned = '' # converted string
cur = 0 # position cursor
while True:
m = pat.search(s)
if m is None:
# append the rest of string
scanned += s
break
# get Mathematica function name
fm = m.group()
# get arguments, and the end position of fm function
args, end = self._get_args(m)
# the start position of fm function
bgn = m.start()
# convert Mathematica function to SymPy one
s = self._convert_one_function(s, fm, args, bgn, end)
# update cursor
cur = bgn
# append converted part
scanned += s[:cur]
# shrink s
s = s[cur:]
return scanned
def _convert_one_function(self, s, fm, args, bgn, end):
# no variable-length argument
if (fm, len(args)) in self.translations:
key = (fm, len(args))
# x, y,... model arguments
x_args = self.translations[key]['args']
# make CORRESPONDENCES between model arguments and actual ones
d = dict(zip(x_args, args))
# with variable-length argument
elif (fm, '*') in self.translations:
key = (fm, '*')
# x, y,..*args (model arguments)
x_args = self.translations[key]['args']
# make CORRESPONDENCES between model arguments and actual ones
d = {}
for i, x in enumerate(x_args):
if x[0] == '*':
d[x] = ','.join(args[i:])
break
d[x] = args[i]
# out of self.translations
else:
err = "'{f}' is out of the whitelist.".format(f=fm)
raise ValueError(err)
# template string of converted function
template = self.translations[key]['fs']
# regex pattern for x_args
pat = self.translations[key]['pat']
scanned = ''
cur = 0
while True:
m = pat.search(template)
if m is None:
scanned += template
break
# get model argument
x = m.group()
# get a start position of the model argument
xbgn = m.start()
# add the corresponding actual argument
scanned += template[:xbgn] + d[x]
# update cursor to the end of the model argument
cur = m.end()
# shrink template
template = template[cur:]
# update to swapped string
s = s[:bgn] + scanned + s[end:]
return s
@classmethod
def _get_args(cls, m):
'''Get arguments of a Mathematica function'''
s = m.string # whole string
anc = m.end() + 1 # pointing the first letter of arguments
square, curly = [], [] # stack for brakets
args = []
# current cursor
cur = anc
for i, c in enumerate(s[anc:], anc):
# extract one argument
if c == ',' and (not square) and (not curly):
args.append(s[cur:i]) # add an argument
cur = i + 1 # move cursor
# handle list or matrix (for future usage)
if c == '{':
curly.append(c)
elif c == '}':
curly.pop()
# seek corresponding ']' with skipping irrevant ones
if c == '[':
square.append(c)
elif c == ']':
if square:
square.pop()
else: # empty stack
args.append(s[cur:i])
break
# the next position to ']' bracket (the function end)
func_end = i + 1
return args, func_end
@classmethod
def _replace(cls, s, bef):
aft = cls.REPLACEMENTS[bef]
s = s.replace(bef, aft)
return s
@classmethod
def _apply_rules(cls, s, bef):
pat, aft = cls.RULES[bef]
return pat.sub(aft, s)
@classmethod
def _check_input(cls, s):
for bracket in (('[', ']'), ('{', '}'), ('(', ')')):
if s.count(bracket[0]) != s.count(bracket[1]):
err = "'{f}' function form is invalid.".format(f=s)
raise ValueError(err)
if '{' in s:
err = "Currently list is not supported."
raise ValueError(err)
def _parse_old(self, s):
# input check
self._check_input(s)
# uncover '*' hiding behind a whitespace
s = self._apply_rules(s, 'whitespace')
# remove whitespace(s)
s = self._replace(s, ' ')
# add omitted '*' character
s = self._apply_rules(s, 'add*_1')
s = self._apply_rules(s, 'add*_2')
# translate function
s = self._convert_function(s)
# '^' to '**'
s = self._replace(s, '^')
# 'Pi' to 'pi'
s = self._apply_rules(s, 'Pi')
# '{', '}' to '[', ']', respectively
# s = cls._replace(s, '{') # currently list is not taken into account
# s = cls._replace(s, '}')
return s
def parse(self, s):
s2 = self._from_mathematica_to_tokens(s)
s3 = self._from_tokens_to_fullformlist(s2)
s4 = self._from_fullformlist_to_sympy(s3)
return s4
INFIX = "Infix"
PREFIX = "Prefix"
POSTFIX = "Postfix"
FLAT = "Flat"
RIGHT = "Right"
LEFT = "Left"
_mathematica_op_precedence: list[tuple[str, str | None, dict[str, str | Callable]]] = [
(POSTFIX, None, {";": lambda x: x + ["Null"] if isinstance(x, list) and x and x[0] == "CompoundExpression" else ["CompoundExpression", x, "Null"]}),
(INFIX, FLAT, {";": "CompoundExpression"}),
(INFIX, RIGHT, {"=": "Set", ":=": "SetDelayed", "+=": "AddTo", "-=": "SubtractFrom", "*=": "TimesBy", "/=": "DivideBy"}),
(INFIX, LEFT, {"//": lambda x, y: [x, y]}),
(POSTFIX, None, {"&": "Function"}),
(INFIX, LEFT, {"/.": "ReplaceAll"}),
(INFIX, RIGHT, {"->": "Rule", ":>": "RuleDelayed"}),
(INFIX, LEFT, {"/;": "Condition"}),
(INFIX, FLAT, {"|": "Alternatives"}),
(POSTFIX, None, {"..": "Repeated", "...": "RepeatedNull"}),
(INFIX, FLAT, {"||": "Or"}),
(INFIX, FLAT, {"&&": "And"}),
(PREFIX, None, {"!": "Not"}),
(INFIX, FLAT, {"===": "SameQ", "=!=": "UnsameQ"}),
(INFIX, FLAT, {"==": "Equal", "!=": "Unequal", "<=": "LessEqual", "<": "Less", ">=": "GreaterEqual", ">": "Greater"}),
(INFIX, None, {";;": "Span"}),
(INFIX, FLAT, {"+": "Plus", "-": "Plus"}),
(INFIX, FLAT, {"*": "Times", "/": "Times"}),
(INFIX, FLAT, {".": "Dot"}),
(PREFIX, None, {"-": lambda x: MathematicaParser._get_neg(x),
"+": lambda x: x}),
(INFIX, RIGHT, {"^": "Power"}),
(INFIX, RIGHT, {"@@": "Apply", "/@": "Map", "//@": "MapAll", "@@@": lambda x, y: ["Apply", x, y, ["List", "1"]]}),
(POSTFIX, None, {"'": "Derivative", "!": "Factorial", "!!": "Factorial2", "--": "Decrement"}),
(INFIX, None, {"[": lambda x, y: [x, *y], "[[": lambda x, y: ["Part", x, *y]}),
(PREFIX, None, {"{": lambda x: ["List", *x], "(": lambda x: x[0]}),
(INFIX, None, {"?": "PatternTest"}),
(POSTFIX, None, {
"_": lambda x: ["Pattern", x, ["Blank"]],
"_.": lambda x: ["Optional", ["Pattern", x, ["Blank"]]],
"__": lambda x: ["Pattern", x, ["BlankSequence"]],
"___": lambda x: ["Pattern", x, ["BlankNullSequence"]],
}),
(INFIX, None, {"_": lambda x, y: ["Pattern", x, ["Blank", y]]}),
(PREFIX, None, {"#": "Slot", "##": "SlotSequence"}),
]
_missing_arguments_default = {
"#": lambda: ["Slot", "1"],
"##": lambda: ["SlotSequence", "1"],
}
_literal = r"[A-Za-z][A-Za-z0-9]*"
_number = r"(?:[0-9]+(?:\.[0-9]*)?|\.[0-9]+)"
_enclosure_open = ["(", "[", "[[", "{"]
_enclosure_close = [")", "]", "]]", "}"]
@classmethod
def _get_neg(cls, x):
return f"-{x}" if isinstance(x, str) and re.match(MathematicaParser._number, x) else ["Times", "-1", x]
@classmethod
def _get_inv(cls, x):
return ["Power", x, "-1"]
_regex_tokenizer = None
def _get_tokenizer(self):
if self._regex_tokenizer is not None:
# Check if the regular expression has already been compiled:
return self._regex_tokenizer
tokens = [self._literal, self._number]
tokens_escape = self._enclosure_open[:] + self._enclosure_close[:]
for typ, strat, symdict in self._mathematica_op_precedence:
for k in symdict:
tokens_escape.append(k)
tokens_escape.sort(key=lambda x: -len(x))
tokens.extend(map(re.escape, tokens_escape))
tokens.append(",")
tokens.append("\n")
tokenizer = re.compile("(" + "|".join(tokens) + ")")
self._regex_tokenizer = tokenizer
return self._regex_tokenizer
def _from_mathematica_to_tokens(self, code: str):
tokenizer = self._get_tokenizer()
# Find strings:
code_splits: list[str | list] = []
while True:
string_start = code.find("\"")
if string_start == -1:
if len(code) > 0:
code_splits.append(code)
break
match_end = re.search(r'(?<!\\)"', code[string_start+1:])
if match_end is None:
raise SyntaxError('mismatch in string " " expression')
string_end = string_start + match_end.start() + 1
if string_start > 0:
code_splits.append(code[:string_start])
code_splits.append(["_Str", code[string_start+1:string_end].replace('\\"', '"')])
code = code[string_end+1:]
# Remove comments:
for i, code_split in enumerate(code_splits):
if isinstance(code_split, list):
continue
while True:
pos_comment_start = code_split.find("(*")
if pos_comment_start == -1:
break
pos_comment_end = code_split.find("*)")
if pos_comment_end == -1 or pos_comment_end < pos_comment_start:
raise SyntaxError("mismatch in comment (* *) code")
code_split = code_split[:pos_comment_start] + code_split[pos_comment_end+2:]
code_splits[i] = code_split
# Tokenize the input strings with a regular expression:
token_lists = [tokenizer.findall(i) if isinstance(i, str) and i.isascii() else [i] for i in code_splits]
tokens = [j for i in token_lists for j in i]
# Remove newlines at the beginning
while tokens and tokens[0] == "\n":
tokens.pop(0)
# Remove newlines at the end
while tokens and tokens[-1] == "\n":
tokens.pop(-1)
return tokens
def _is_op(self, token: str | list) -> bool:
if isinstance(token, list):
return False
if re.match(self._literal, token):
return False
if re.match("-?" + self._number, token):
return False
return True
def _is_valid_star1(self, token: str | list) -> bool:
if token in (")", "}"):
return True
return not self._is_op(token)
def _is_valid_star2(self, token: str | list) -> bool:
if token in ("(", "{"):
return True
return not self._is_op(token)
def _from_tokens_to_fullformlist(self, tokens: list):
stack: list[list] = [[]]
open_seq = []
pointer: int = 0
while pointer < len(tokens):
token = tokens[pointer]
if token in self._enclosure_open:
stack[-1].append(token)
open_seq.append(token)
stack.append([])
elif token == ",":
if len(stack[-1]) == 0 and stack[-2][-1] == open_seq[-1]:
raise SyntaxError("%s cannot be followed by comma ," % open_seq[-1])
stack[-1] = self._parse_after_braces(stack[-1])
stack.append([])
elif token in self._enclosure_close:
ind = self._enclosure_close.index(token)
if self._enclosure_open[ind] != open_seq[-1]:
unmatched_enclosure = SyntaxError("unmatched enclosure")
if token == "]]" and open_seq[-1] == "[":
if open_seq[-2] == "[":
# These two lines would be logically correct, but are
# unnecessary:
# token = "]"
# tokens[pointer] = "]"
tokens.insert(pointer+1, "]")
elif open_seq[-2] == "[[":
if tokens[pointer+1] == "]":
tokens[pointer+1] = "]]"
elif tokens[pointer+1] == "]]":
tokens[pointer+1] = "]]"
tokens.insert(pointer+2, "]")
else:
raise unmatched_enclosure
else:
raise unmatched_enclosure
if len(stack[-1]) == 0 and stack[-2][-1] == "(":
raise SyntaxError("( ) not valid syntax")
last_stack = self._parse_after_braces(stack[-1], True)
stack[-1] = last_stack
new_stack_element = []
while stack[-1][-1] != open_seq[-1]:
new_stack_element.append(stack.pop())
new_stack_element.reverse()
if open_seq[-1] == "(" and len(new_stack_element) != 1:
raise SyntaxError("( must be followed by one expression, %i detected" % len(new_stack_element))
stack[-1].append(new_stack_element)
open_seq.pop(-1)
else:
stack[-1].append(token)
pointer += 1
if len(stack) != 1:
raise RuntimeError("Stack should have only one element")
return self._parse_after_braces(stack[0])
def _util_remove_newlines(self, lines: list, tokens: list, inside_enclosure: bool):
pointer = 0
size = len(tokens)
while pointer < size:
token = tokens[pointer]
if token == "\n":
if inside_enclosure:
# Ignore newlines inside enclosures
tokens.pop(pointer)
size -= 1
continue
if pointer == 0:
tokens.pop(0)
size -= 1
continue
if pointer > 1:
try:
prev_expr = self._parse_after_braces(tokens[:pointer], inside_enclosure)
except SyntaxError:
tokens.pop(pointer)
size -= 1
continue
else:
prev_expr = tokens[0]
if len(prev_expr) > 0 and prev_expr[0] == "CompoundExpression":
lines.extend(prev_expr[1:])
else:
lines.append(prev_expr)
for i in range(pointer):
tokens.pop(0)
size -= pointer
pointer = 0
continue
pointer += 1
def _util_add_missing_asterisks(self, tokens: list):
size: int = len(tokens)
pointer: int = 0
while pointer < size:
if (pointer > 0 and
self._is_valid_star1(tokens[pointer - 1]) and
self._is_valid_star2(tokens[pointer])):
# This is a trick to add missing * operators in the expression,
# `"*" in op_dict` makes sure the precedence level is the same as "*",
# while `not self._is_op( ... )` makes sure this and the previous
# expression are not operators.
if tokens[pointer] == "(":
# ( has already been processed by now, replace:
tokens[pointer] = "*"
tokens[pointer + 1] = tokens[pointer + 1][0]
else:
tokens.insert(pointer, "*")
pointer += 1
size += 1
pointer += 1
def _parse_after_braces(self, tokens: list, inside_enclosure: bool = False):
op_dict: dict
changed: bool = False
lines: list = []
self._util_remove_newlines(lines, tokens, inside_enclosure)
for op_type, grouping_strat, op_dict in reversed(self._mathematica_op_precedence):
if "*" in op_dict:
self._util_add_missing_asterisks(tokens)
size: int = len(tokens)
pointer: int = 0
while pointer < size:
token = tokens[pointer]
if isinstance(token, str) and token in op_dict:
op_name: str | Callable = op_dict[token]
node: list
first_index: int
if isinstance(op_name, str):
node = [op_name]
first_index = 1
else:
node = []
first_index = 0
if token in ("+", "-") and op_type == self.PREFIX and pointer > 0 and not self._is_op(tokens[pointer - 1]):
# Make sure that PREFIX + - don't match expressions like a + b or a - b,
# the INFIX + - are supposed to match that expression:
pointer += 1
continue
if op_type == self.INFIX:
if pointer == 0 or pointer == size - 1 or self._is_op(tokens[pointer - 1]) or self._is_op(tokens[pointer + 1]):
pointer += 1
continue
changed = True
tokens[pointer] = node
if op_type == self.INFIX:
arg1 = tokens.pop(pointer-1)
arg2 = tokens.pop(pointer)
if token == "/":
arg2 = self._get_inv(arg2)
elif token == "-":
arg2 = self._get_neg(arg2)
pointer -= 1
size -= 2
node.append(arg1)
node_p = node
if grouping_strat == self.FLAT:
while pointer + 2 < size and self._check_op_compatible(tokens[pointer+1], token):
node_p.append(arg2)
other_op = tokens.pop(pointer+1)
arg2 = tokens.pop(pointer+1)
if other_op == "/":
arg2 = self._get_inv(arg2)
elif other_op == "-":
arg2 = self._get_neg(arg2)
size -= 2
node_p.append(arg2)
elif grouping_strat == self.RIGHT:
while pointer + 2 < size and tokens[pointer+1] == token:
node_p.append([op_name, arg2])
node_p = node_p[-1]
tokens.pop(pointer+1)
arg2 = tokens.pop(pointer+1)
size -= 2
node_p.append(arg2)
elif grouping_strat == self.LEFT:
while pointer + 1 < size and tokens[pointer+1] == token:
if isinstance(op_name, str):
node_p[first_index] = [op_name, node_p[first_index], arg2]
else:
node_p[first_index] = op_name(node_p[first_index], arg2)
tokens.pop(pointer+1)
arg2 = tokens.pop(pointer+1)
size -= 2
node_p.append(arg2)
else:
node.append(arg2)
elif op_type == self.PREFIX:
if grouping_strat is not None:
raise TypeError("'Prefix' op_type should not have a grouping strat")
if pointer == size - 1 or self._is_op(tokens[pointer + 1]):
tokens[pointer] = self._missing_arguments_default[token]()
else:
node.append(tokens.pop(pointer+1))
size -= 1
elif op_type == self.POSTFIX:
if grouping_strat is not None:
raise TypeError("'Prefix' op_type should not have a grouping strat")
if pointer == 0 or self._is_op(tokens[pointer - 1]):
tokens[pointer] = self._missing_arguments_default[token]()
else:
node.append(tokens.pop(pointer-1))
pointer -= 1
size -= 1
if isinstance(op_name, Callable): # type: ignore
op_call: Callable = typing.cast(Callable, op_name)
new_node = op_call(*node)
node.clear()
if isinstance(new_node, list):
node.extend(new_node)
else:
tokens[pointer] = new_node
pointer += 1
if len(tokens) > 1 or (len(lines) == 0 and len(tokens) == 0):
if changed:
# Trick to deal with cases in which an operator with lower
# precedence should be transformed before an operator of higher
# precedence. Such as in the case of `#&[x]` (that is
# equivalent to `Lambda(d_, d_)(x)` in SymPy). In this case the
# operator `&` has lower precedence than `[`, but needs to be
# evaluated first because otherwise `# (&[x])` is not a valid
# expression:
return self._parse_after_braces(tokens, inside_enclosure)
raise SyntaxError("unable to create a single AST for the expression")
if len(lines) > 0:
if tokens[0] and tokens[0][0] == "CompoundExpression":
tokens = tokens[0][1:]
compound_expression = ["CompoundExpression", *lines, *tokens]
return compound_expression
return tokens[0]
def _check_op_compatible(self, op1: str, op2: str):
if op1 == op2:
return True
muldiv = {"*", "/"}
addsub = {"+", "-"}
if op1 in muldiv and op2 in muldiv:
return True
if op1 in addsub and op2 in addsub:
return True
return False
def _from_fullform_to_fullformlist(self, wmexpr: str):
"""
Parses FullForm[Downvalues[]] generated by Mathematica
"""
out: list = []
stack = [out]
generator = re.finditer(r'[\[\],]', wmexpr)
last_pos = 0
for match in generator:
if match is None:
break
position = match.start()
last_expr = wmexpr[last_pos:position].replace(',', '').replace(']', '').replace('[', '').strip()
if match.group() == ',':
if last_expr != '':
stack[-1].append(last_expr)
elif match.group() == ']':
if last_expr != '':
stack[-1].append(last_expr)
stack.pop()
elif match.group() == '[':
stack[-1].append([last_expr])
stack.append(stack[-1][-1])
last_pos = match.end()
return out[0]
def _from_fullformlist_to_fullformsympy(self, pylist: list):
from sympy import Function, Symbol
def converter(expr):
if isinstance(expr, list):
if len(expr) > 0:
head = expr[0]
args = [converter(arg) for arg in expr[1:]]
return Function(head)(*args)
else:
raise ValueError("Empty list of expressions")
elif isinstance(expr, str):
return Symbol(expr)
else:
return _sympify(expr)
return converter(pylist)
_node_conversions = {
"Times": Mul,
"Plus": Add,
"Power": Pow,
"Rational": Rational,
"Log": lambda *a: log(*reversed(a)),
"Log2": lambda x: log(x, 2),
"Log10": lambda x: log(x, 10),
"Rational": Rational,
"Exp": exp,
"Sqrt": sqrt,
"Sin": sin,
"Cos": cos,
"Tan": tan,
"Cot": cot,
"Sec": sec,
"Csc": csc,
"ArcSin": asin,
"ArcCos": acos,
"ArcTan": lambda *a: atan2(*reversed(a)) if len(a) == 2 else atan(*a),
"ArcCot": acot,
"ArcSec": asec,
"ArcCsc": acsc,
"Sinh": sinh,
"Cosh": cosh,
"Tanh": tanh,
"Coth": coth,
"Sech": sech,
"Csch": csch,
"ArcSinh": asinh,
"ArcCosh": acosh,
"ArcTanh": atanh,
"ArcCoth": acoth,
"ArcSech": asech,
"ArcCsch": acsch,
"Expand": expand,
"Im": im,
"Re": sympy.re,
"Flatten": flatten,
"Polylog": polylog,
"Cancel": cancel,
# Gamma=gamma,
"TrigExpand": expand_trig,
"Sign": sign,
"Simplify": simplify,
"Defer": UnevaluatedExpr,
"Identity": S,
# Sum=Sum_doit,
# Module=With,
# Block=With,
"Null": lambda *a: S.Zero,
"Mod": Mod,
"Max": Max,
"Min": Min,
"Pochhammer": rf,
"ExpIntegralEi": Ei,
"SinIntegral": Si,
"CosIntegral": Ci,
"AiryAi": airyai,
"AiryAiPrime": airyaiprime,
"AiryBi": airybi,
"AiryBiPrime": airybiprime,
"LogIntegral": li,
"PrimePi": primepi,
"Prime": prime,
"PrimeQ": isprime,
"List": Tuple,
"Greater": StrictGreaterThan,
"GreaterEqual": GreaterThan,
"Less": StrictLessThan,
"LessEqual": LessThan,
"Equal": Equality,
"Or": Or,
"And": And,
"Function": _parse_Function,
}
_atom_conversions = {
"I": I,
"Pi": pi,
}
def _from_fullformlist_to_sympy(self, full_form_list):
def recurse(expr):
if isinstance(expr, list):
if isinstance(expr[0], list):
head = recurse(expr[0])
else:
head = self._node_conversions.get(expr[0], Function(expr[0]))
return head(*[recurse(arg) for arg in expr[1:]])
else:
return self._atom_conversions.get(expr, sympify(expr))
return recurse(full_form_list)
def _from_fullformsympy_to_sympy(self, mform):
expr = mform
for mma_form, sympy_node in self._node_conversions.items():
expr = expr.replace(Function(mma_form), sympy_node)
return expr
PK ]ZZZ���+ + sympy/parsing/maxima.pyimport re
from sympy.concrete.products import product
from sympy.concrete.summations import Sum
from sympy.core.sympify import sympify
from sympy.functions.elementary.trigonometric import (cos, sin)
class MaximaHelpers:
def maxima_expand(expr):
return expr.expand()
def maxima_float(expr):
return expr.evalf()
def maxima_trigexpand(expr):
return expr.expand(trig=True)
def maxima_sum(a1, a2, a3, a4):
return Sum(a1, (a2, a3, a4)).doit()
def maxima_product(a1, a2, a3, a4):
return product(a1, (a2, a3, a4))
def maxima_csc(expr):
return 1/sin(expr)
def maxima_sec(expr):
return 1/cos(expr)
sub_dict = {
'pi': re.compile(r'%pi'),
'E': re.compile(r'%e'),
'I': re.compile(r'%i'),
'**': re.compile(r'\^'),
'oo': re.compile(r'\binf\b'),
'-oo': re.compile(r'\bminf\b'),
"'-'": re.compile(r'\bminus\b'),
'maxima_expand': re.compile(r'\bexpand\b'),
'maxima_float': re.compile(r'\bfloat\b'),
'maxima_trigexpand': re.compile(r'\btrigexpand'),
'maxima_sum': re.compile(r'\bsum\b'),
'maxima_product': re.compile(r'\bproduct\b'),
'cancel': re.compile(r'\bratsimp\b'),
'maxima_csc': re.compile(r'\bcsc\b'),
'maxima_sec': re.compile(r'\bsec\b')
}
var_name = re.compile(r'^\s*(\w+)\s*:')
def parse_maxima(str, globals=None, name_dict={}):
str = str.strip()
str = str.rstrip('; ')
for k, v in sub_dict.items():
str = v.sub(k, str)
assign_var = None
var_match = var_name.search(str)
if var_match:
assign_var = var_match.group(1)
str = str[var_match.end():].strip()
dct = MaximaHelpers.__dict__.copy()
dct.update(name_dict)
obj = sympify(str, locals=dct)
if assign_var and globals:
globals[assign_var] = obj
return obj
PK ]ZZZk�z%�" �" sympy/parsing/sym_expr.pyfrom sympy.printing import pycode, ccode, fcode
from sympy.external import import_module
from sympy.utilities.decorator import doctest_depends_on
lfortran = import_module('lfortran')
cin = import_module('clang.cindex', import_kwargs = {'fromlist': ['cindex']})
if lfortran:
from sympy.parsing.fortran.fortran_parser import src_to_sympy
if cin:
from sympy.parsing.c.c_parser import parse_c
@doctest_depends_on(modules=['lfortran', 'clang.cindex'])
class SymPyExpression: # type: ignore
"""Class to store and handle SymPy expressions
This class will hold SymPy Expressions and handle the API for the
conversion to and from different languages.
It works with the C and the Fortran Parser to generate SymPy expressions
which are stored here and which can be converted to multiple language's
source code.
Notes
=====
The module and its API are currently under development and experimental
and can be changed during development.
The Fortran parser does not support numeric assignments, so all the
variables have been Initialized to zero.
The module also depends on external dependencies:
- LFortran which is required to use the Fortran parser
- Clang which is required for the C parser
Examples
========
Example of parsing C code:
>>> from sympy.parsing.sym_expr import SymPyExpression
>>> src = '''
... int a,b;
... float c = 2, d =4;
... '''
>>> a = SymPyExpression(src, 'c')
>>> a.return_expr()
[Declaration(Variable(a, type=intc)),
Declaration(Variable(b, type=intc)),
Declaration(Variable(c, type=float32, value=2.0)),
Declaration(Variable(d, type=float32, value=4.0))]
An example of variable definition:
>>> from sympy.parsing.sym_expr import SymPyExpression
>>> src2 = '''
... integer :: a, b, c, d
... real :: p, q, r, s
... '''
>>> p = SymPyExpression()
>>> p.convert_to_expr(src2, 'f')
>>> p.convert_to_c()
['int a = 0', 'int b = 0', 'int c = 0', 'int d = 0', 'double p = 0.0', 'double q = 0.0', 'double r = 0.0', 'double s = 0.0']
An example of Assignment:
>>> from sympy.parsing.sym_expr import SymPyExpression
>>> src3 = '''
... integer :: a, b, c, d, e
... d = a + b - c
... e = b * d + c * e / a
... '''
>>> p = SymPyExpression(src3, 'f')
>>> p.convert_to_python()
['a = 0', 'b = 0', 'c = 0', 'd = 0', 'e = 0', 'd = a + b - c', 'e = b*d + c*e/a']
An example of function definition:
>>> from sympy.parsing.sym_expr import SymPyExpression
>>> src = '''
... integer function f(a,b)
... integer, intent(in) :: a, b
... integer :: r
... end function
... '''
>>> a = SymPyExpression(src, 'f')
>>> a.convert_to_python()
['def f(a, b):\\n f = 0\\n r = 0\\n return f']
"""
def __init__(self, source_code = None, mode = None):
"""Constructor for SymPyExpression class"""
super().__init__()
if not(mode or source_code):
self._expr = []
elif mode:
if source_code:
if mode.lower() == 'f':
if lfortran:
self._expr = src_to_sympy(source_code)
else:
raise ImportError("LFortran is not installed, cannot parse Fortran code")
elif mode.lower() == 'c':
if cin:
self._expr = parse_c(source_code)
else:
raise ImportError("Clang is not installed, cannot parse C code")
else:
raise NotImplementedError(
'Parser for specified language is not implemented'
)
else:
raise ValueError('Source code not present')
else:
raise ValueError('Please specify a mode for conversion')
def convert_to_expr(self, src_code, mode):
"""Converts the given source code to SymPy Expressions
Attributes
==========
src_code : String
the source code or filename of the source code that is to be
converted
mode: String
the mode to determine which parser is to be used according to
the language of the source code
f or F for Fortran
c or C for C/C++
Examples
========
>>> from sympy.parsing.sym_expr import SymPyExpression
>>> src3 = '''
... integer function f(a,b) result(r)
... integer, intent(in) :: a, b
... integer :: x
... r = a + b -x
... end function
... '''
>>> p = SymPyExpression()
>>> p.convert_to_expr(src3, 'f')
>>> p.return_expr()
[FunctionDefinition(integer, name=f, parameters=(Variable(a), Variable(b)), body=CodeBlock(
Declaration(Variable(r, type=integer, value=0)),
Declaration(Variable(x, type=integer, value=0)),
Assignment(Variable(r), a + b - x),
Return(Variable(r))
))]
"""
if mode.lower() == 'f':
if lfortran:
self._expr = src_to_sympy(src_code)
else:
raise ImportError("LFortran is not installed, cannot parse Fortran code")
elif mode.lower() == 'c':
if cin:
self._expr = parse_c(src_code)
else:
raise ImportError("Clang is not installed, cannot parse C code")
else:
raise NotImplementedError(
"Parser for specified language has not been implemented"
)
def convert_to_python(self):
"""Returns a list with Python code for the SymPy expressions
Examples
========
>>> from sympy.parsing.sym_expr import SymPyExpression
>>> src2 = '''
... integer :: a, b, c, d
... real :: p, q, r, s
... c = a/b
... d = c/a
... s = p/q
... r = q/p
... '''
>>> p = SymPyExpression(src2, 'f')
>>> p.convert_to_python()
['a = 0', 'b = 0', 'c = 0', 'd = 0', 'p = 0.0', 'q = 0.0', 'r = 0.0', 's = 0.0', 'c = a/b', 'd = c/a', 's = p/q', 'r = q/p']
"""
self._pycode = []
for iter in self._expr:
self._pycode.append(pycode(iter))
return self._pycode
def convert_to_c(self):
"""Returns a list with the c source code for the SymPy expressions
Examples
========
>>> from sympy.parsing.sym_expr import SymPyExpression
>>> src2 = '''
... integer :: a, b, c, d
... real :: p, q, r, s
... c = a/b
... d = c/a
... s = p/q
... r = q/p
... '''
>>> p = SymPyExpression()
>>> p.convert_to_expr(src2, 'f')
>>> p.convert_to_c()
['int a = 0', 'int b = 0', 'int c = 0', 'int d = 0', 'double p = 0.0', 'double q = 0.0', 'double r = 0.0', 'double s = 0.0', 'c = a/b;', 'd = c/a;', 's = p/q;', 'r = q/p;']
"""
self._ccode = []
for iter in self._expr:
self._ccode.append(ccode(iter))
return self._ccode
def convert_to_fortran(self):
"""Returns a list with the fortran source code for the SymPy expressions
Examples
========
>>> from sympy.parsing.sym_expr import SymPyExpression
>>> src2 = '''
... integer :: a, b, c, d
... real :: p, q, r, s
... c = a/b
... d = c/a
... s = p/q
... r = q/p
... '''
>>> p = SymPyExpression(src2, 'f')
>>> p.convert_to_fortran()
[' integer*4 a', ' integer*4 b', ' integer*4 c', ' integer*4 d', ' real*8 p', ' real*8 q', ' real*8 r', ' real*8 s', ' c = a/b', ' d = c/a', ' s = p/q', ' r = q/p']
"""
self._fcode = []
for iter in self._expr:
self._fcode.append(fcode(iter))
return self._fcode
def return_expr(self):
"""Returns the expression list
Examples
========
>>> from sympy.parsing.sym_expr import SymPyExpression
>>> src3 = '''
... integer function f(a,b)
... integer, intent(in) :: a, b
... integer :: r
... r = a+b
... f = r
... end function
... '''
>>> p = SymPyExpression()
>>> p.convert_to_expr(src3, 'f')
>>> p.return_expr()
[FunctionDefinition(integer, name=f, parameters=(Variable(a), Variable(b)), body=CodeBlock(
Declaration(Variable(f, type=integer, value=0)),
Declaration(Variable(r, type=integer, value=0)),
Assignment(Variable(f), Variable(r)),
Return(Variable(f))
))]
"""
return self._expr
PK ]ZZZ~Ndxܩ ܩ sympy/parsing/sympy_parser.py"""Transform a string with Python-like source code into SymPy expression. """
from tokenize import (generate_tokens, untokenize, TokenError,
NUMBER, STRING, NAME, OP, ENDMARKER, ERRORTOKEN, NEWLINE)
from keyword import iskeyword
import ast
import unicodedata
from io import StringIO
import builtins
import types
from typing import Tuple as tTuple, Dict as tDict, Any, Callable, \
List, Optional, Union as tUnion
from sympy.assumptions.ask import AssumptionKeys
from sympy.core.basic import Basic
from sympy.core import Symbol
from sympy.core.function import Function
from sympy.utilities.misc import func_name
from sympy.functions.elementary.miscellaneous import Max, Min
null = ''
TOKEN = tTuple[int, str]
DICT = tDict[str, Any]
TRANS = Callable[[List[TOKEN], DICT, DICT], List[TOKEN]]
def _token_splittable(token_name: str) -> bool:
"""
Predicate for whether a token name can be split into multiple tokens.
A token is splittable if it does not contain an underscore character and
it is not the name of a Greek letter. This is used to implicitly convert
expressions like 'xyz' into 'x*y*z'.
"""
if '_' in token_name:
return False
try:
return not unicodedata.lookup('GREEK SMALL LETTER ' + token_name)
except KeyError:
return len(token_name) > 1
def _token_callable(token: TOKEN, local_dict: DICT, global_dict: DICT, nextToken=None):
"""
Predicate for whether a token name represents a callable function.
Essentially wraps ``callable``, but looks up the token name in the
locals and globals.
"""
func = local_dict.get(token[1])
if not func:
func = global_dict.get(token[1])
return callable(func) and not isinstance(func, Symbol)
def _add_factorial_tokens(name: str, result: List[TOKEN]) -> List[TOKEN]:
if result == [] or result[-1][1] == '(':
raise TokenError()
beginning = [(NAME, name), (OP, '(')]
end = [(OP, ')')]
diff = 0
length = len(result)
for index, token in enumerate(result[::-1]):
toknum, tokval = token
i = length - index - 1
if tokval == ')':
diff += 1
elif tokval == '(':
diff -= 1
if diff == 0:
if i - 1 >= 0 and result[i - 1][0] == NAME:
return result[:i - 1] + beginning + result[i - 1:] + end
else:
return result[:i] + beginning + result[i:] + end
return result
class ParenthesisGroup(List[TOKEN]):
"""List of tokens representing an expression in parentheses."""
pass
class AppliedFunction:
"""
A group of tokens representing a function and its arguments.
`exponent` is for handling the shorthand sin^2, ln^2, etc.
"""
def __init__(self, function: TOKEN, args: ParenthesisGroup, exponent=None):
if exponent is None:
exponent = []
self.function = function
self.args = args
self.exponent = exponent
self.items = ['function', 'args', 'exponent']
def expand(self) -> List[TOKEN]:
"""Return a list of tokens representing the function"""
return [self.function, *self.args]
def __getitem__(self, index):
return getattr(self, self.items[index])
def __repr__(self):
return "AppliedFunction(%s, %s, %s)" % (self.function, self.args,
self.exponent)
def _flatten(result: List[tUnion[TOKEN, AppliedFunction]]):
result2: List[TOKEN] = []
for tok in result:
if isinstance(tok, AppliedFunction):
result2.extend(tok.expand())
else:
result2.append(tok)
return result2
def _group_parentheses(recursor: TRANS):
def _inner(tokens: List[TOKEN], local_dict: DICT, global_dict: DICT):
"""Group tokens between parentheses with ParenthesisGroup.
Also processes those tokens recursively.
"""
result: List[tUnion[TOKEN, ParenthesisGroup]] = []
stacks: List[ParenthesisGroup] = []
stacklevel = 0
for token in tokens:
if token[0] == OP:
if token[1] == '(':
stacks.append(ParenthesisGroup([]))
stacklevel += 1
elif token[1] == ')':
stacks[-1].append(token)
stack = stacks.pop()
if len(stacks) > 0:
# We don't recurse here since the upper-level stack
# would reprocess these tokens
stacks[-1].extend(stack)
else:
# Recurse here to handle nested parentheses
# Strip off the outer parentheses to avoid an infinite loop
inner = stack[1:-1]
inner = recursor(inner,
local_dict,
global_dict)
parenGroup = [stack[0]] + inner + [stack[-1]]
result.append(ParenthesisGroup(parenGroup))
stacklevel -= 1
continue
if stacklevel:
stacks[-1].append(token)
else:
result.append(token)
if stacklevel:
raise TokenError("Mismatched parentheses")
return result
return _inner
def _apply_functions(tokens: List[tUnion[TOKEN, ParenthesisGroup]], local_dict: DICT, global_dict: DICT):
"""Convert a NAME token + ParenthesisGroup into an AppliedFunction.
Note that ParenthesisGroups, if not applied to any function, are
converted back into lists of tokens.
"""
result: List[tUnion[TOKEN, AppliedFunction]] = []
symbol = None
for tok in tokens:
if isinstance(tok, ParenthesisGroup):
if symbol and _token_callable(symbol, local_dict, global_dict):
result[-1] = AppliedFunction(symbol, tok)
symbol = None
else:
result.extend(tok)
elif tok[0] == NAME:
symbol = tok
result.append(tok)
else:
symbol = None
result.append(tok)
return result
def _implicit_multiplication(tokens: List[tUnion[TOKEN, AppliedFunction]], local_dict: DICT, global_dict: DICT):
"""Implicitly adds '*' tokens.
Cases:
- Two AppliedFunctions next to each other ("sin(x)cos(x)")
- AppliedFunction next to an open parenthesis ("sin x (cos x + 1)")
- A close parenthesis next to an AppliedFunction ("(x+2)sin x")\
- A close parenthesis next to an open parenthesis ("(x+2)(x+3)")
- AppliedFunction next to an implicitly applied function ("sin(x)cos x")
"""
result: List[tUnion[TOKEN, AppliedFunction]] = []
skip = False
for tok, nextTok in zip(tokens, tokens[1:]):
result.append(tok)
if skip:
skip = False
continue
if tok[0] == OP and tok[1] == '.' and nextTok[0] == NAME:
# Dotted name. Do not do implicit multiplication
skip = True
continue
if isinstance(tok, AppliedFunction):
if isinstance(nextTok, AppliedFunction):
result.append((OP, '*'))
elif nextTok == (OP, '('):
# Applied function followed by an open parenthesis
if tok.function[1] == "Function":
tok.function = (tok.function[0], 'Symbol')
result.append((OP, '*'))
elif nextTok[0] == NAME:
# Applied function followed by implicitly applied function
result.append((OP, '*'))
else:
if tok == (OP, ')'):
if isinstance(nextTok, AppliedFunction):
# Close parenthesis followed by an applied function
result.append((OP, '*'))
elif nextTok[0] == NAME:
# Close parenthesis followed by an implicitly applied function
result.append((OP, '*'))
elif nextTok == (OP, '('):
# Close parenthesis followed by an open parenthesis
result.append((OP, '*'))
elif tok[0] == NAME and not _token_callable(tok, local_dict, global_dict):
if isinstance(nextTok, AppliedFunction) or \
(nextTok[0] == NAME and _token_callable(nextTok, local_dict, global_dict)):
# Constant followed by (implicitly applied) function
result.append((OP, '*'))
elif nextTok == (OP, '('):
# Constant followed by parenthesis
result.append((OP, '*'))
elif nextTok[0] == NAME:
# Constant followed by constant
result.append((OP, '*'))
if tokens:
result.append(tokens[-1])
return result
def _implicit_application(tokens: List[tUnion[TOKEN, AppliedFunction]], local_dict: DICT, global_dict: DICT):
"""Adds parentheses as needed after functions."""
result: List[tUnion[TOKEN, AppliedFunction]] = []
appendParen = 0 # number of closing parentheses to add
skip = 0 # number of tokens to delay before adding a ')' (to
# capture **, ^, etc.)
exponentSkip = False # skipping tokens before inserting parentheses to
# work with function exponentiation
for tok, nextTok in zip(tokens, tokens[1:]):
result.append(tok)
if (tok[0] == NAME and nextTok[0] not in [OP, ENDMARKER, NEWLINE]):
if _token_callable(tok, local_dict, global_dict, nextTok): # type: ignore
result.append((OP, '('))
appendParen += 1
# name followed by exponent - function exponentiation
elif (tok[0] == NAME and nextTok[0] == OP and nextTok[1] == '**'):
if _token_callable(tok, local_dict, global_dict): # type: ignore
exponentSkip = True
elif exponentSkip:
# if the last token added was an applied function (i.e. the
# power of the function exponent) OR a multiplication (as
# implicit multiplication would have added an extraneous
# multiplication)
if (isinstance(tok, AppliedFunction)
or (tok[0] == OP and tok[1] == '*')):
# don't add anything if the next token is a multiplication
# or if there's already a parenthesis (if parenthesis, still
# stop skipping tokens)
if not (nextTok[0] == OP and nextTok[1] == '*'):
if not(nextTok[0] == OP and nextTok[1] == '('):
result.append((OP, '('))
appendParen += 1
exponentSkip = False
elif appendParen:
if nextTok[0] == OP and nextTok[1] in ('^', '**', '*'):
skip = 1
continue
if skip:
skip -= 1
continue
result.append((OP, ')'))
appendParen -= 1
if tokens:
result.append(tokens[-1])
if appendParen:
result.extend([(OP, ')')] * appendParen)
return result
def function_exponentiation(tokens: List[TOKEN], local_dict: DICT, global_dict: DICT):
"""Allows functions to be exponentiated, e.g. ``cos**2(x)``.
Examples
========
>>> from sympy.parsing.sympy_parser import (parse_expr,
... standard_transformations, function_exponentiation)
>>> transformations = standard_transformations + (function_exponentiation,)
>>> parse_expr('sin**4(x)', transformations=transformations)
sin(x)**4
"""
result: List[TOKEN] = []
exponent: List[TOKEN] = []
consuming_exponent = False
level = 0
for tok, nextTok in zip(tokens, tokens[1:]):
if tok[0] == NAME and nextTok[0] == OP and nextTok[1] == '**':
if _token_callable(tok, local_dict, global_dict):
consuming_exponent = True
elif consuming_exponent:
if tok[0] == NAME and tok[1] == 'Function':
tok = (NAME, 'Symbol')
exponent.append(tok)
# only want to stop after hitting )
if tok[0] == nextTok[0] == OP and tok[1] == ')' and nextTok[1] == '(':
consuming_exponent = False
# if implicit multiplication was used, we may have )*( instead
if tok[0] == nextTok[0] == OP and tok[1] == '*' and nextTok[1] == '(':
consuming_exponent = False
del exponent[-1]
continue
elif exponent and not consuming_exponent:
if tok[0] == OP:
if tok[1] == '(':
level += 1
elif tok[1] == ')':
level -= 1
if level == 0:
result.append(tok)
result.extend(exponent)
exponent = []
continue
result.append(tok)
if tokens:
result.append(tokens[-1])
if exponent:
result.extend(exponent)
return result
def split_symbols_custom(predicate: Callable[[str], bool]):
"""Creates a transformation that splits symbol names.
``predicate`` should return True if the symbol name is to be split.
For instance, to retain the default behavior but avoid splitting certain
symbol names, a predicate like this would work:
>>> from sympy.parsing.sympy_parser import (parse_expr, _token_splittable,
... standard_transformations, implicit_multiplication,
... split_symbols_custom)
>>> def can_split(symbol):
... if symbol not in ('list', 'of', 'unsplittable', 'names'):
... return _token_splittable(symbol)
... return False
...
>>> transformation = split_symbols_custom(can_split)
>>> parse_expr('unsplittable', transformations=standard_transformations +
... (transformation, implicit_multiplication))
unsplittable
"""
def _split_symbols(tokens: List[TOKEN], local_dict: DICT, global_dict: DICT):
result: List[TOKEN] = []
split = False
split_previous=False
for tok in tokens:
if split_previous:
# throw out closing parenthesis of Symbol that was split
split_previous=False
continue
split_previous=False
if tok[0] == NAME and tok[1] in ['Symbol', 'Function']:
split = True
elif split and tok[0] == NAME:
symbol = tok[1][1:-1]
if predicate(symbol):
tok_type = result[-2][1] # Symbol or Function
del result[-2:] # Get rid of the call to Symbol
i = 0
while i < len(symbol):
char = symbol[i]
if char in local_dict or char in global_dict:
result.append((NAME, "%s" % char))
elif char.isdigit():
chars = [char]
for i in range(i + 1, len(symbol)):
if not symbol[i].isdigit():
i -= 1
break
chars.append(symbol[i])
char = ''.join(chars)
result.extend([(NAME, 'Number'), (OP, '('),
(NAME, "'%s'" % char), (OP, ')')])
else:
use = tok_type if i == len(symbol) else 'Symbol'
result.extend([(NAME, use), (OP, '('),
(NAME, "'%s'" % char), (OP, ')')])
i += 1
# Set split_previous=True so will skip
# the closing parenthesis of the original Symbol
split = False
split_previous = True
continue
else:
split = False
result.append(tok)
return result
return _split_symbols
#: Splits symbol names for implicit multiplication.
#:
#: Intended to let expressions like ``xyz`` be parsed as ``x*y*z``. Does not
#: split Greek character names, so ``theta`` will *not* become
#: ``t*h*e*t*a``. Generally this should be used with
#: ``implicit_multiplication``.
split_symbols = split_symbols_custom(_token_splittable)
def implicit_multiplication(tokens: List[TOKEN], local_dict: DICT,
global_dict: DICT) -> List[TOKEN]:
"""Makes the multiplication operator optional in most cases.
Use this before :func:`implicit_application`, otherwise expressions like
``sin 2x`` will be parsed as ``x * sin(2)`` rather than ``sin(2*x)``.
Examples
========
>>> from sympy.parsing.sympy_parser import (parse_expr,
... standard_transformations, implicit_multiplication)
>>> transformations = standard_transformations + (implicit_multiplication,)
>>> parse_expr('3 x y', transformations=transformations)
3*x*y
"""
# These are interdependent steps, so we don't expose them separately
res1 = _group_parentheses(implicit_multiplication)(tokens, local_dict, global_dict)
res2 = _apply_functions(res1, local_dict, global_dict)
res3 = _implicit_multiplication(res2, local_dict, global_dict)
result = _flatten(res3)
return result
def implicit_application(tokens: List[TOKEN], local_dict: DICT,
global_dict: DICT) -> List[TOKEN]:
"""Makes parentheses optional in some cases for function calls.
Use this after :func:`implicit_multiplication`, otherwise expressions
like ``sin 2x`` will be parsed as ``x * sin(2)`` rather than
``sin(2*x)``.
Examples
========
>>> from sympy.parsing.sympy_parser import (parse_expr,
... standard_transformations, implicit_application)
>>> transformations = standard_transformations + (implicit_application,)
>>> parse_expr('cot z + csc z', transformations=transformations)
cot(z) + csc(z)
"""
res1 = _group_parentheses(implicit_application)(tokens, local_dict, global_dict)
res2 = _apply_functions(res1, local_dict, global_dict)
res3 = _implicit_application(res2, local_dict, global_dict)
result = _flatten(res3)
return result
def implicit_multiplication_application(result: List[TOKEN], local_dict: DICT,
global_dict: DICT) -> List[TOKEN]:
"""Allows a slightly relaxed syntax.
- Parentheses for single-argument method calls are optional.
- Multiplication is implicit.
- Symbol names can be split (i.e. spaces are not needed between
symbols).
- Functions can be exponentiated.
Examples
========
>>> from sympy.parsing.sympy_parser import (parse_expr,
... standard_transformations, implicit_multiplication_application)
>>> parse_expr("10sin**2 x**2 + 3xyz + tan theta",
... transformations=(standard_transformations +
... (implicit_multiplication_application,)))
3*x*y*z + 10*sin(x**2)**2 + tan(theta)
"""
for step in (split_symbols, implicit_multiplication,
implicit_application, function_exponentiation):
result = step(result, local_dict, global_dict)
return result
def auto_symbol(tokens: List[TOKEN], local_dict: DICT, global_dict: DICT):
"""Inserts calls to ``Symbol``/``Function`` for undefined variables."""
result: List[TOKEN] = []
prevTok = (-1, '')
tokens.append((-1, '')) # so zip traverses all tokens
for tok, nextTok in zip(tokens, tokens[1:]):
tokNum, tokVal = tok
nextTokNum, nextTokVal = nextTok
if tokNum == NAME:
name = tokVal
if (name in ['True', 'False', 'None']
or iskeyword(name)
# Don't convert attribute access
or (prevTok[0] == OP and prevTok[1] == '.')
# Don't convert keyword arguments
or (prevTok[0] == OP and prevTok[1] in ('(', ',')
and nextTokNum == OP and nextTokVal == '=')
# the name has already been defined
or name in local_dict and local_dict[name] is not null):
result.append((NAME, name))
continue
elif name in local_dict:
local_dict.setdefault(null, set()).add(name)
if nextTokVal == '(':
local_dict[name] = Function(name)
else:
local_dict[name] = Symbol(name)
result.append((NAME, name))
continue
elif name in global_dict:
obj = global_dict[name]
if isinstance(obj, (AssumptionKeys, Basic, type)) or callable(obj):
result.append((NAME, name))
continue
result.extend([
(NAME, 'Symbol' if nextTokVal != '(' else 'Function'),
(OP, '('),
(NAME, repr(str(name))),
(OP, ')'),
])
else:
result.append((tokNum, tokVal))
prevTok = (tokNum, tokVal)
return result
def lambda_notation(tokens: List[TOKEN], local_dict: DICT, global_dict: DICT):
"""Substitutes "lambda" with its SymPy equivalent Lambda().
However, the conversion does not take place if only "lambda"
is passed because that is a syntax error.
"""
result: List[TOKEN] = []
flag = False
toknum, tokval = tokens[0]
tokLen = len(tokens)
if toknum == NAME and tokval == 'lambda':
if tokLen == 2 or tokLen == 3 and tokens[1][0] == NEWLINE:
# In Python 3.6.7+, inputs without a newline get NEWLINE added to
# the tokens
result.extend(tokens)
elif tokLen > 2:
result.extend([
(NAME, 'Lambda'),
(OP, '('),
(OP, '('),
(OP, ')'),
(OP, ')'),
])
for tokNum, tokVal in tokens[1:]:
if tokNum == OP and tokVal == ':':
tokVal = ','
flag = True
if not flag and tokNum == OP and tokVal in ('*', '**'):
raise TokenError("Starred arguments in lambda not supported")
if flag:
result.insert(-1, (tokNum, tokVal))
else:
result.insert(-2, (tokNum, tokVal))
else:
result.extend(tokens)
return result
def factorial_notation(tokens: List[TOKEN], local_dict: DICT, global_dict: DICT):
"""Allows standard notation for factorial."""
result: List[TOKEN] = []
nfactorial = 0
for toknum, tokval in tokens:
if toknum == OP and tokval == "!":
# In Python 3.12 "!" are OP instead of ERRORTOKEN
nfactorial += 1
elif toknum == ERRORTOKEN:
op = tokval
if op == '!':
nfactorial += 1
else:
nfactorial = 0
result.append((OP, op))
else:
if nfactorial == 1:
result = _add_factorial_tokens('factorial', result)
elif nfactorial == 2:
result = _add_factorial_tokens('factorial2', result)
elif nfactorial > 2:
raise TokenError
nfactorial = 0
result.append((toknum, tokval))
return result
def convert_xor(tokens: List[TOKEN], local_dict: DICT, global_dict: DICT):
"""Treats XOR, ``^``, as exponentiation, ``**``."""
result: List[TOKEN] = []
for toknum, tokval in tokens:
if toknum == OP:
if tokval == '^':
result.append((OP, '**'))
else:
result.append((toknum, tokval))
else:
result.append((toknum, tokval))
return result
def repeated_decimals(tokens: List[TOKEN], local_dict: DICT, global_dict: DICT):
"""
Allows 0.2[1] notation to represent the repeated decimal 0.2111... (19/90)
Run this before auto_number.
"""
result: List[TOKEN] = []
def is_digit(s):
return all(i in '0123456789_' for i in s)
# num will running match any DECIMAL [ INTEGER ]
num: List[TOKEN] = []
for toknum, tokval in tokens:
if toknum == NUMBER:
if (not num and '.' in tokval and 'e' not in tokval.lower() and
'j' not in tokval.lower()):
num.append((toknum, tokval))
elif is_digit(tokval)and len(num) == 2:
num.append((toknum, tokval))
elif is_digit(tokval) and len(num) == 3 and is_digit(num[-1][1]):
# Python 2 tokenizes 00123 as '00', '123'
# Python 3 tokenizes 01289 as '012', '89'
num.append((toknum, tokval))
else:
num = []
elif toknum == OP:
if tokval == '[' and len(num) == 1:
num.append((OP, tokval))
elif tokval == ']' and len(num) >= 3:
num.append((OP, tokval))
elif tokval == '.' and not num:
# handle .[1]
num.append((NUMBER, '0.'))
else:
num = []
else:
num = []
result.append((toknum, tokval))
if num and num[-1][1] == ']':
# pre.post[repetend] = a + b/c + d/e where a = pre, b/c = post,
# and d/e = repetend
result = result[:-len(num)]
pre, post = num[0][1].split('.')
repetend = num[2][1]
if len(num) == 5:
repetend += num[3][1]
pre = pre.replace('_', '')
post = post.replace('_', '')
repetend = repetend.replace('_', '')
zeros = '0'*len(post)
post, repetends = [w.lstrip('0') for w in [post, repetend]]
# or else interpreted as octal
a = pre or '0'
b, c = post or '0', '1' + zeros
d, e = repetends, ('9'*len(repetend)) + zeros
seq = [
(OP, '('),
(NAME, 'Integer'),
(OP, '('),
(NUMBER, a),
(OP, ')'),
(OP, '+'),
(NAME, 'Rational'),
(OP, '('),
(NUMBER, b),
(OP, ','),
(NUMBER, c),
(OP, ')'),
(OP, '+'),
(NAME, 'Rational'),
(OP, '('),
(NUMBER, d),
(OP, ','),
(NUMBER, e),
(OP, ')'),
(OP, ')'),
]
result.extend(seq)
num = []
return result
def auto_number(tokens: List[TOKEN], local_dict: DICT, global_dict: DICT):
"""
Converts numeric literals to use SymPy equivalents.
Complex numbers use ``I``, integer literals use ``Integer``, and float
literals use ``Float``.
"""
result: List[TOKEN] = []
for toknum, tokval in tokens:
if toknum == NUMBER:
number = tokval
postfix = []
if number.endswith(('j', 'J')):
number = number[:-1]
postfix = [(OP, '*'), (NAME, 'I')]
if '.' in number or (('e' in number or 'E' in number) and
not (number.startswith(('0x', '0X')))):
seq = [(NAME, 'Float'), (OP, '('),
(NUMBER, repr(str(number))), (OP, ')')]
else:
seq = [(NAME, 'Integer'), (OP, '('), (
NUMBER, number), (OP, ')')]
result.extend(seq + postfix)
else:
result.append((toknum, tokval))
return result
def rationalize(tokens: List[TOKEN], local_dict: DICT, global_dict: DICT):
"""Converts floats into ``Rational``. Run AFTER ``auto_number``."""
result: List[TOKEN] = []
passed_float = False
for toknum, tokval in tokens:
if toknum == NAME:
if tokval == 'Float':
passed_float = True
tokval = 'Rational'
result.append((toknum, tokval))
elif passed_float == True and toknum == NUMBER:
passed_float = False
result.append((STRING, tokval))
else:
result.append((toknum, tokval))
return result
def _transform_equals_sign(tokens: List[TOKEN], local_dict: DICT, global_dict: DICT):
"""Transforms the equals sign ``=`` to instances of Eq.
This is a helper function for ``convert_equals_signs``.
Works with expressions containing one equals sign and no
nesting. Expressions like ``(1=2)=False`` will not work with this
and should be used with ``convert_equals_signs``.
Examples: 1=2 to Eq(1,2)
1*2=x to Eq(1*2, x)
This does not deal with function arguments yet.
"""
result: List[TOKEN] = []
if (OP, "=") in tokens:
result.append((NAME, "Eq"))
result.append((OP, "("))
for token in tokens:
if token == (OP, "="):
result.append((OP, ","))
continue
result.append(token)
result.append((OP, ")"))
else:
result = tokens
return result
def convert_equals_signs(tokens: List[TOKEN], local_dict: DICT,
global_dict: DICT) -> List[TOKEN]:
""" Transforms all the equals signs ``=`` to instances of Eq.
Parses the equals signs in the expression and replaces them with
appropriate Eq instances. Also works with nested equals signs.
Does not yet play well with function arguments.
For example, the expression ``(x=y)`` is ambiguous and can be interpreted
as x being an argument to a function and ``convert_equals_signs`` will not
work for this.
See also
========
convert_equality_operators
Examples
========
>>> from sympy.parsing.sympy_parser import (parse_expr,
... standard_transformations, convert_equals_signs)
>>> parse_expr("1*2=x", transformations=(
... standard_transformations + (convert_equals_signs,)))
Eq(2, x)
>>> parse_expr("(1*2=x)=False", transformations=(
... standard_transformations + (convert_equals_signs,)))
Eq(Eq(2, x), False)
"""
res1 = _group_parentheses(convert_equals_signs)(tokens, local_dict, global_dict)
res2 = _apply_functions(res1, local_dict, global_dict)
res3 = _transform_equals_sign(res2, local_dict, global_dict)
result = _flatten(res3)
return result
#: Standard transformations for :func:`parse_expr`.
#: Inserts calls to :class:`~.Symbol`, :class:`~.Integer`, and other SymPy
#: datatypes and allows the use of standard factorial notation (e.g. ``x!``).
standard_transformations: tTuple[TRANS, ...] \
= (lambda_notation, auto_symbol, repeated_decimals, auto_number,
factorial_notation)
def stringify_expr(s: str, local_dict: DICT, global_dict: DICT,
transformations: tTuple[TRANS, ...]) -> str:
"""
Converts the string ``s`` to Python code, in ``local_dict``
Generally, ``parse_expr`` should be used.
"""
tokens = []
input_code = StringIO(s.strip())
for toknum, tokval, _, _, _ in generate_tokens(input_code.readline):
tokens.append((toknum, tokval))
for transform in transformations:
tokens = transform(tokens, local_dict, global_dict)
return untokenize(tokens)
def eval_expr(code, local_dict: DICT, global_dict: DICT):
"""
Evaluate Python code generated by ``stringify_expr``.
Generally, ``parse_expr`` should be used.
"""
expr = eval(
code, global_dict, local_dict) # take local objects in preference
return expr
def parse_expr(s: str, local_dict: Optional[DICT] = None,
transformations: tUnion[tTuple[TRANS, ...], str] \
= standard_transformations,
global_dict: Optional[DICT] = None, evaluate=True):
"""Converts the string ``s`` to a SymPy expression, in ``local_dict``.
Parameters
==========
s : str
The string to parse.
local_dict : dict, optional
A dictionary of local variables to use when parsing.
global_dict : dict, optional
A dictionary of global variables. By default, this is initialized
with ``from sympy import *``; provide this parameter to override
this behavior (for instance, to parse ``"Q & S"``).
transformations : tuple or str
A tuple of transformation functions used to modify the tokens of the
parsed expression before evaluation. The default transformations
convert numeric literals into their SymPy equivalents, convert
undefined variables into SymPy symbols, and allow the use of standard
mathematical factorial notation (e.g. ``x!``). Selection via
string is available (see below).
evaluate : bool, optional
When False, the order of the arguments will remain as they were in the
string and automatic simplification that would normally occur is
suppressed. (see examples)
Examples
========
>>> from sympy.parsing.sympy_parser import parse_expr
>>> parse_expr("1/2")
1/2
>>> type(_)
<class 'sympy.core.numbers.Half'>
>>> from sympy.parsing.sympy_parser import standard_transformations,\\
... implicit_multiplication_application
>>> transformations = (standard_transformations +
... (implicit_multiplication_application,))
>>> parse_expr("2x", transformations=transformations)
2*x
When evaluate=False, some automatic simplifications will not occur:
>>> parse_expr("2**3"), parse_expr("2**3", evaluate=False)
(8, 2**3)
In addition the order of the arguments will not be made canonical.
This feature allows one to tell exactly how the expression was entered:
>>> a = parse_expr('1 + x', evaluate=False)
>>> b = parse_expr('x + 1', evaluate=0)
>>> a == b
False
>>> a.args
(1, x)
>>> b.args
(x, 1)
Note, however, that when these expressions are printed they will
appear the same:
>>> assert str(a) == str(b)
As a convenience, transformations can be seen by printing ``transformations``:
>>> from sympy.parsing.sympy_parser import transformations
>>> print(transformations)
0: lambda_notation
1: auto_symbol
2: repeated_decimals
3: auto_number
4: factorial_notation
5: implicit_multiplication_application
6: convert_xor
7: implicit_application
8: implicit_multiplication
9: convert_equals_signs
10: function_exponentiation
11: rationalize
The ``T`` object provides a way to select these transformations:
>>> from sympy.parsing.sympy_parser import T
If you print it, you will see the same list as shown above.
>>> str(T) == str(transformations)
True
Standard slicing will return a tuple of transformations:
>>> T[:5] == standard_transformations
True
So ``T`` can be used to specify the parsing transformations:
>>> parse_expr("2x", transformations=T[:5])
Traceback (most recent call last):
...
SyntaxError: invalid syntax
>>> parse_expr("2x", transformations=T[:6])
2*x
>>> parse_expr('.3', transformations=T[3, 11])
3/10
>>> parse_expr('.3x', transformations=T[:])
3*x/10
As a further convenience, strings 'implicit' and 'all' can be used
to select 0-5 and all the transformations, respectively.
>>> parse_expr('.3x', transformations='all')
3*x/10
See Also
========
stringify_expr, eval_expr, standard_transformations,
implicit_multiplication_application
"""
if local_dict is None:
local_dict = {}
elif not isinstance(local_dict, dict):
raise TypeError('expecting local_dict to be a dict')
elif null in local_dict:
raise ValueError('cannot use "" in local_dict')
if global_dict is None:
global_dict = {}
exec('from sympy import *', global_dict)
builtins_dict = vars(builtins)
for name, obj in builtins_dict.items():
if isinstance(obj, types.BuiltinFunctionType):
global_dict[name] = obj
global_dict['max'] = Max
global_dict['min'] = Min
elif not isinstance(global_dict, dict):
raise TypeError('expecting global_dict to be a dict')
transformations = transformations or ()
if isinstance(transformations, str):
if transformations == 'all':
_transformations = T[:]
elif transformations == 'implicit':
_transformations = T[:6]
else:
raise ValueError('unknown transformation group name')
else:
_transformations = transformations
code = stringify_expr(s, local_dict, global_dict, _transformations)
if not evaluate:
code = compile(evaluateFalse(code), '<string>', 'eval') # type: ignore
try:
rv = eval_expr(code, local_dict, global_dict)
# restore neutral definitions for names
for i in local_dict.pop(null, ()):
local_dict[i] = null
return rv
except Exception as e:
# restore neutral definitions for names
for i in local_dict.pop(null, ()):
local_dict[i] = null
raise e from ValueError(f"Error from parse_expr with transformed code: {code!r}")
def evaluateFalse(s: str):
"""
Replaces operators with the SymPy equivalent and sets evaluate=False.
"""
node = ast.parse(s)
transformed_node = EvaluateFalseTransformer().visit(node)
# node is a Module, we want an Expression
transformed_node = ast.Expression(transformed_node.body[0].value)
return ast.fix_missing_locations(transformed_node)
class EvaluateFalseTransformer(ast.NodeTransformer):
operators = {
ast.Add: 'Add',
ast.Mult: 'Mul',
ast.Pow: 'Pow',
ast.Sub: 'Add',
ast.Div: 'Mul',
ast.BitOr: 'Or',
ast.BitAnd: 'And',
ast.BitXor: 'Not',
}
functions = (
'Abs', 'im', 're', 'sign', 'arg', 'conjugate',
'acos', 'acot', 'acsc', 'asec', 'asin', 'atan',
'acosh', 'acoth', 'acsch', 'asech', 'asinh', 'atanh',
'cos', 'cot', 'csc', 'sec', 'sin', 'tan',
'cosh', 'coth', 'csch', 'sech', 'sinh', 'tanh',
'exp', 'ln', 'log', 'sqrt', 'cbrt',
)
relational_operators = {
ast.NotEq: 'Ne',
ast.Lt: 'Lt',
ast.LtE: 'Le',
ast.Gt: 'Gt',
ast.GtE: 'Ge',
ast.Eq: 'Eq'
}
def visit_Compare(self, node):
if node.ops[0].__class__ in self.relational_operators:
sympy_class = self.relational_operators[node.ops[0].__class__]
right = self.visit(node.comparators[0])
left = self.visit(node.left)
new_node = ast.Call(
func=ast.Name(id=sympy_class, ctx=ast.Load()),
args=[left, right],
keywords=[ast.keyword(arg='evaluate', value=ast.Constant(value=False))]
)
return new_node
return node
def flatten(self, args, func):
result = []
for arg in args:
if isinstance(arg, ast.Call):
arg_func = arg.func
if isinstance(arg_func, ast.Call):
arg_func = arg_func.func
if arg_func.id == func:
result.extend(self.flatten(arg.args, func))
else:
result.append(arg)
else:
result.append(arg)
return result
def visit_BinOp(self, node):
if node.op.__class__ in self.operators:
sympy_class = self.operators[node.op.__class__]
right = self.visit(node.right)
left = self.visit(node.left)
rev = False
if isinstance(node.op, ast.Sub):
right = ast.Call(
func=ast.Name(id='Mul', ctx=ast.Load()),
args=[ast.UnaryOp(op=ast.USub(), operand=ast.Constant(1)), right],
keywords=[ast.keyword(arg='evaluate', value=ast.Constant(value=False))]
)
elif isinstance(node.op, ast.Div):
if isinstance(node.left, ast.UnaryOp):
left, right = right, left
rev = True
left = ast.Call(
func=ast.Name(id='Pow', ctx=ast.Load()),
args=[left, ast.UnaryOp(op=ast.USub(), operand=ast.Constant(1))],
keywords=[ast.keyword(arg='evaluate', value=ast.Constant(value=False))]
)
else:
right = ast.Call(
func=ast.Name(id='Pow', ctx=ast.Load()),
args=[right, ast.UnaryOp(op=ast.USub(), operand=ast.Constant(1))],
keywords=[ast.keyword(arg='evaluate', value=ast.Constant(value=False))]
)
if rev: # undo reversal
left, right = right, left
new_node = ast.Call(
func=ast.Name(id=sympy_class, ctx=ast.Load()),
args=[left, right],
keywords=[ast.keyword(arg='evaluate', value=ast.Constant(value=False))]
)
if sympy_class in ('Add', 'Mul'):
# Denest Add or Mul as appropriate
new_node.args = self.flatten(new_node.args, sympy_class)
return new_node
return node
def visit_Call(self, node):
new_node = self.generic_visit(node)
if isinstance(node.func, ast.Name) and node.func.id in self.functions:
new_node.keywords.append(ast.keyword(arg='evaluate', value=ast.Constant(value=False)))
return new_node
_transformation = { # items can be added but never re-ordered
0: lambda_notation,
1: auto_symbol,
2: repeated_decimals,
3: auto_number,
4: factorial_notation,
5: implicit_multiplication_application,
6: convert_xor,
7: implicit_application,
8: implicit_multiplication,
9: convert_equals_signs,
10: function_exponentiation,
11: rationalize}
transformations = '\n'.join('%s: %s' % (i, func_name(f)) for i, f in _transformation.items())
class _T():
"""class to retrieve transformations from a given slice
EXAMPLES
========
>>> from sympy.parsing.sympy_parser import T, standard_transformations
>>> assert T[:5] == standard_transformations
"""
def __init__(self):
self.N = len(_transformation)
def __str__(self):
return transformations
def __getitem__(self, t):
if not type(t) is tuple:
t = (t,)
i = []
for ti in t:
if type(ti) is int:
i.append(range(self.N)[ti])
elif type(ti) is slice:
i.extend(range(*ti.indices(self.N)))
else:
raise TypeError('unexpected slice arg')
return tuple([_transformation[_] for _ in i])
T = _T()
PK ]ZZZ4���c c sympy/parsing/autolev/Autolev.g4grammar Autolev;
options {
language = Python3;
}
prog: stat+;
stat: varDecl
| functionCall
| codeCommands
| massDecl
| inertiaDecl
| assignment
| settings
;
assignment: vec equals expr #vecAssign
| ID '[' index ']' equals expr #indexAssign
| ID diff? equals expr #regularAssign;
equals: ('='|'+='|'-='|':='|'*='|'/='|'^=');
index: expr (',' expr)* ;
diff: ('\'')+;
functionCall: ID '(' (expr (',' expr)*)? ')'
| (Mass|Inertia) '(' (ID (',' ID)*)? ')';
varDecl: varType varDecl2 (',' varDecl2)*;
varType: Newtonian|Frames|Bodies|Particles|Points|Constants
| Specifieds|Imaginary|Variables ('\'')*|MotionVariables ('\'')*;
varDecl2: ID ('{' INT ',' INT '}')? (('{' INT ':' INT (',' INT ':' INT)* '}'))? ('{' INT '}')? ('+'|'-')? ('\'')* ('=' expr)?;
ranges: ('{' INT ':' INT (',' INT ':' INT)* '}');
massDecl: Mass massDecl2 (',' massDecl2)*;
massDecl2: ID '=' expr;
inertiaDecl: Inertia ID ('(' ID ')')? (',' expr)+;
matrix: '[' expr ((','|';') expr)* ']';
matrixInOutput: (ID (ID '=' (FLOAT|INT)?))|FLOAT|INT;
codeCommands: units
| inputs
| outputs
| codegen
| commands;
settings: ID (EXP|ID|FLOAT|INT)?;
units: UnitSystem ID (',' ID)*;
inputs: Input inputs2 (',' inputs2)*;
id_diff: ID diff?;
inputs2: id_diff '=' expr expr?;
outputs: Output outputs2 (',' outputs2)*;
outputs2: expr expr?;
codegen: ID functionCall ('['matrixInOutput (',' matrixInOutput)*']')? ID'.'ID;
commands: Save ID'.'ID
| Encode ID (',' ID)*;
vec: ID ('>')+
| '0>'
| '1>>';
expr: expr '^'<assoc=right> expr # Exponent
| expr ('*'|'/') expr # MulDiv
| expr ('+'|'-') expr # AddSub
| EXP # exp
| '-' expr # negativeOne
| FLOAT # float
| INT # int
| ID('\'')* # id
| vec # VectorOrDyadic
| ID '['expr (',' expr)* ']' # Indexing
| functionCall # function
| matrix # matrices
| '(' expr ')' # parens
| expr '=' expr # idEqualsExpr
| expr ':' expr # colon
| ID? ranges ('\'')* # rangess
;
// These are to take care of the case insensitivity of Autolev.
Mass: ('M'|'m')('A'|'a')('S'|'s')('S'|'s');
Inertia: ('I'|'i')('N'|'n')('E'|'e')('R'|'r')('T'|'t')('I'|'i')('A'|'a');
Input: ('I'|'i')('N'|'n')('P'|'p')('U'|'u')('T'|'t')('S'|'s')?;
Output: ('O'|'o')('U'|'u')('T'|'t')('P'|'p')('U'|'u')('T'|'t');
Save: ('S'|'s')('A'|'a')('V'|'v')('E'|'e');
UnitSystem: ('U'|'u')('N'|'n')('I'|'i')('T'|'t')('S'|'s')('Y'|'y')('S'|'s')('T'|'t')('E'|'e')('M'|'m');
Encode: ('E'|'e')('N'|'n')('C'|'c')('O'|'o')('D'|'d')('E'|'e');
Newtonian: ('N'|'n')('E'|'e')('W'|'w')('T'|'t')('O'|'o')('N'|'n')('I'|'i')('A'|'a')('N'|'n');
Frames: ('F'|'f')('R'|'r')('A'|'a')('M'|'m')('E'|'e')('S'|'s')?;
Bodies: ('B'|'b')('O'|'o')('D'|'d')('I'|'i')('E'|'e')('S'|'s')?;
Particles: ('P'|'p')('A'|'a')('R'|'r')('T'|'t')('I'|'i')('C'|'c')('L'|'l')('E'|'e')('S'|'s')?;
Points: ('P'|'p')('O'|'o')('I'|'i')('N'|'n')('T'|'t')('S'|'s')?;
Constants: ('C'|'c')('O'|'o')('N'|'n')('S'|'s')('T'|'t')('A'|'a')('N'|'n')('T'|'t')('S'|'s')?;
Specifieds: ('S'|'s')('P'|'p')('E'|'e')('C'|'c')('I'|'i')('F'|'f')('I'|'i')('E'|'e')('D'|'d')('S'|'s')?;
Imaginary: ('I'|'i')('M'|'m')('A'|'a')('G'|'g')('I'|'i')('N'|'n')('A'|'a')('R'|'r')('Y'|'y');
Variables: ('V'|'v')('A'|'a')('R'|'r')('I'|'i')('A'|'a')('B'|'b')('L'|'l')('E'|'e')('S'|'s')?;
MotionVariables: ('M'|'m')('O'|'o')('T'|'t')('I'|'i')('O'|'o')('N'|'n')('V'|'v')('A'|'a')('R'|'r')('I'|'i')('A'|'a')('B'|'b')('L'|'l')('E'|'e')('S'|'s')?;
fragment DIFF: ('\'')*;
fragment DIGIT: [0-9];
INT: [0-9]+ ; // match integers
FLOAT: DIGIT+ '.' DIGIT*
| '.' DIGIT+;
EXP: FLOAT 'E' INT
| FLOAT 'E' '-' INT;
LINE_COMMENT : '%' .*? '\r'? '\n' -> skip ;
ID: [a-zA-Z][a-zA-Z0-9_]*;
WS: [ \t\r\n&]+ -> skip ; // toss out whitespace
PK ]ZZZ'��� ! sympy/parsing/autolev/__init__.pyfrom sympy.external import import_module
from sympy.utilities.decorator import doctest_depends_on
@doctest_depends_on(modules=('antlr4',))
def parse_autolev(autolev_code, include_numeric=False):
"""Parses Autolev code (version 4.1) to SymPy code.
Parameters
=========
autolev_code : Can be an str or any object with a readlines() method (such as a file handle or StringIO).
include_numeric : boolean, optional
If True NumPy, PyDy, or other numeric code is included for numeric evaluation lines in the Autolev code.
Returns
=======
sympy_code : str
Equivalent SymPy and/or numpy/pydy code as the input code.
Example (Double Pendulum)
=========================
>>> my_al_text = ("MOTIONVARIABLES' Q{2}', U{2}'",
... "CONSTANTS L,M,G",
... "NEWTONIAN N",
... "FRAMES A,B",
... "SIMPROT(N, A, 3, Q1)",
... "SIMPROT(N, B, 3, Q2)",
... "W_A_N>=U1*N3>",
... "W_B_N>=U2*N3>",
... "POINT O",
... "PARTICLES P,R",
... "P_O_P> = L*A1>",
... "P_P_R> = L*B1>",
... "V_O_N> = 0>",
... "V2PTS(N, A, O, P)",
... "V2PTS(N, B, P, R)",
... "MASS P=M, R=M",
... "Q1' = U1",
... "Q2' = U2",
... "GRAVITY(G*N1>)",
... "ZERO = FR() + FRSTAR()",
... "KANE()",
... "INPUT M=1,G=9.81,L=1",
... "INPUT Q1=.1,Q2=.2,U1=0,U2=0",
... "INPUT TFINAL=10, INTEGSTP=.01",
... "CODE DYNAMICS() some_filename.c")
>>> my_al_text = '\\n'.join(my_al_text)
>>> from sympy.parsing.autolev import parse_autolev
>>> print(parse_autolev(my_al_text, include_numeric=True))
import sympy.physics.mechanics as _me
import sympy as _sm
import math as m
import numpy as _np
<BLANKLINE>
q1, q2, u1, u2 = _me.dynamicsymbols('q1 q2 u1 u2')
q1_d, q2_d, u1_d, u2_d = _me.dynamicsymbols('q1_ q2_ u1_ u2_', 1)
l, m, g = _sm.symbols('l m g', real=True)
frame_n = _me.ReferenceFrame('n')
frame_a = _me.ReferenceFrame('a')
frame_b = _me.ReferenceFrame('b')
frame_a.orient(frame_n, 'Axis', [q1, frame_n.z])
frame_b.orient(frame_n, 'Axis', [q2, frame_n.z])
frame_a.set_ang_vel(frame_n, u1*frame_n.z)
frame_b.set_ang_vel(frame_n, u2*frame_n.z)
point_o = _me.Point('o')
particle_p = _me.Particle('p', _me.Point('p_pt'), _sm.Symbol('m'))
particle_r = _me.Particle('r', _me.Point('r_pt'), _sm.Symbol('m'))
particle_p.point.set_pos(point_o, l*frame_a.x)
particle_r.point.set_pos(particle_p.point, l*frame_b.x)
point_o.set_vel(frame_n, 0)
particle_p.point.v2pt_theory(point_o,frame_n,frame_a)
particle_r.point.v2pt_theory(particle_p.point,frame_n,frame_b)
particle_p.mass = m
particle_r.mass = m
force_p = particle_p.mass*(g*frame_n.x)
force_r = particle_r.mass*(g*frame_n.x)
kd_eqs = [q1_d - u1, q2_d - u2]
forceList = [(particle_p.point,particle_p.mass*(g*frame_n.x)), (particle_r.point,particle_r.mass*(g*frame_n.x))]
kane = _me.KanesMethod(frame_n, q_ind=[q1,q2], u_ind=[u1, u2], kd_eqs = kd_eqs)
fr, frstar = kane.kanes_equations([particle_p, particle_r], forceList)
zero = fr+frstar
from pydy.system import System
sys = System(kane, constants = {l:1, m:1, g:9.81},
specifieds={},
initial_conditions={q1:.1, q2:.2, u1:0, u2:0},
times = _np.linspace(0.0, 10, 10/.01))
<BLANKLINE>
y=sys.integrate()
<BLANKLINE>
"""
_autolev = import_module(
'sympy.parsing.autolev._parse_autolev_antlr',
import_kwargs={'fromlist': ['X']})
if _autolev is not None:
return _autolev.parse_autolev(autolev_code, include_numeric)
PK ]ZZZ��
- sympy/parsing/autolev/_build_autolev_antlr.pyimport os
import subprocess
import glob
from sympy.utilities.misc import debug
here = os.path.dirname(__file__)
grammar_file = os.path.abspath(os.path.join(here, "Autolev.g4"))
dir_autolev_antlr = os.path.join(here, "_antlr")
header = '''\
# *** GENERATED BY `setup.py antlr`, DO NOT EDIT BY HAND ***
#
# Generated with antlr4
# antlr4 is licensed under the BSD-3-Clause License
# https://github.com/antlr/antlr4/blob/master/LICENSE.txt
'''
def check_antlr_version():
debug("Checking antlr4 version...")
try:
debug(subprocess.check_output(["antlr4"])
.decode('utf-8').split("\n")[0])
return True
except (subprocess.CalledProcessError, FileNotFoundError):
debug("The 'antlr4' command line tool is not installed, "
"or not on your PATH.\n"
"> Please refer to the README.md file for more information.")
return False
def build_parser(output_dir=dir_autolev_antlr):
check_antlr_version()
debug("Updating ANTLR-generated code in {}".format(output_dir))
if not os.path.exists(output_dir):
os.makedirs(output_dir)
with open(os.path.join(output_dir, "__init__.py"), "w+") as fp:
fp.write(header)
args = [
"antlr4",
grammar_file,
"-o", output_dir,
"-no-visitor",
]
debug("Running code generation...\n\t$ {}".format(" ".join(args)))
subprocess.check_output(args, cwd=output_dir)
debug("Applying headers, removing unnecessary files and renaming...")
# Handle case insensitive file systems. If the files are already
# generated, they will be written to autolev* but Autolev*.* won't match them.
for path in (glob.glob(os.path.join(output_dir, "Autolev*.*")) or
glob.glob(os.path.join(output_dir, "autolev*.*"))):
# Remove files ending in .interp or .tokens as they are not needed.
if not path.endswith(".py"):
os.unlink(path)
continue
new_path = os.path.join(output_dir, os.path.basename(path).lower())
with open(path, 'r') as f:
lines = [line.rstrip().replace('AutolevParser import', 'autolevparser import') +'\n'
for line in f.readlines()]
os.unlink(path)
with open(new_path, "w") as out_file:
offset = 0
while lines[offset].startswith('#'):
offset += 1
out_file.write(header)
out_file.writelines(lines[offset:])
debug("\t{}".format(new_path))
return True
if __name__ == "__main__":
build_parser()
PK ]ZZZ)ޞ6� 6� 0 sympy/parsing/autolev/_listener_autolev_antlr.pyimport collections
import warnings
from sympy.external import import_module
autolevparser = import_module('sympy.parsing.autolev._antlr.autolevparser',
import_kwargs={'fromlist': ['AutolevParser']})
autolevlexer = import_module('sympy.parsing.autolev._antlr.autolevlexer',
import_kwargs={'fromlist': ['AutolevLexer']})
autolevlistener = import_module('sympy.parsing.autolev._antlr.autolevlistener',
import_kwargs={'fromlist': ['AutolevListener']})
AutolevParser = getattr(autolevparser, 'AutolevParser', None)
AutolevLexer = getattr(autolevlexer, 'AutolevLexer', None)
AutolevListener = getattr(autolevlistener, 'AutolevListener', None)
def strfunc(z):
if z == 0:
return ""
elif z == 1:
return "_d"
else:
return "_" + "d" * z
def declare_phy_entities(self, ctx, phy_type, i, j=None):
if phy_type in ("frame", "newtonian"):
declare_frames(self, ctx, i, j)
elif phy_type == "particle":
declare_particles(self, ctx, i, j)
elif phy_type == "point":
declare_points(self, ctx, i, j)
elif phy_type == "bodies":
declare_bodies(self, ctx, i, j)
def declare_frames(self, ctx, i, j=None):
if "{" in ctx.getText():
if j:
name1 = ctx.ID().getText().lower() + str(i) + str(j)
else:
name1 = ctx.ID().getText().lower() + str(i)
else:
name1 = ctx.ID().getText().lower()
name2 = "frame_" + name1
if self.getValue(ctx.parentCtx.varType()) == "newtonian":
self.newtonian = name2
self.symbol_table2.update({name1: name2})
self.symbol_table.update({name1 + "1>": name2 + ".x"})
self.symbol_table.update({name1 + "2>": name2 + ".y"})
self.symbol_table.update({name1 + "3>": name2 + ".z"})
self.type2.update({name1: "frame"})
self.write(name2 + " = " + "_me.ReferenceFrame('" + name1 + "')\n")
def declare_points(self, ctx, i, j=None):
if "{" in ctx.getText():
if j:
name1 = ctx.ID().getText().lower() + str(i) + str(j)
else:
name1 = ctx.ID().getText().lower() + str(i)
else:
name1 = ctx.ID().getText().lower()
name2 = "point_" + name1
self.symbol_table2.update({name1: name2})
self.type2.update({name1: "point"})
self.write(name2 + " = " + "_me.Point('" + name1 + "')\n")
def declare_particles(self, ctx, i, j=None):
if "{" in ctx.getText():
if j:
name1 = ctx.ID().getText().lower() + str(i) + str(j)
else:
name1 = ctx.ID().getText().lower() + str(i)
else:
name1 = ctx.ID().getText().lower()
name2 = "particle_" + name1
self.symbol_table2.update({name1: name2})
self.type2.update({name1: "particle"})
self.bodies.update({name1: name2})
self.write(name2 + " = " + "_me.Particle('" + name1 + "', " + "_me.Point('" +
name1 + "_pt" + "'), " + "_sm.Symbol('m'))\n")
def declare_bodies(self, ctx, i, j=None):
if "{" in ctx.getText():
if j:
name1 = ctx.ID().getText().lower() + str(i) + str(j)
else:
name1 = ctx.ID().getText().lower() + str(i)
else:
name1 = ctx.ID().getText().lower()
name2 = "body_" + name1
self.bodies.update({name1: name2})
masscenter = name2 + "_cm"
refFrame = name2 + "_f"
self.symbol_table2.update({name1: name2})
self.symbol_table2.update({name1 + "o": masscenter})
self.symbol_table.update({name1 + "1>": refFrame+".x"})
self.symbol_table.update({name1 + "2>": refFrame+".y"})
self.symbol_table.update({name1 + "3>": refFrame+".z"})
self.type2.update({name1: "bodies"})
self.type2.update({name1+"o": "point"})
self.write(masscenter + " = " + "_me.Point('" + name1 + "_cm" + "')\n")
if self.newtonian:
self.write(masscenter + ".set_vel(" + self.newtonian + ", " + "0)\n")
self.write(refFrame + " = " + "_me.ReferenceFrame('" + name1 + "_f" + "')\n")
# We set a dummy mass and inertia here.
# They will be reset using the setters later in the code anyway.
self.write(name2 + " = " + "_me.RigidBody('" + name1 + "', " + masscenter + ", " +
refFrame + ", " + "_sm.symbols('m'), (_me.outer(" + refFrame +
".x," + refFrame + ".x)," + masscenter + "))\n")
def inertia_func(self, v1, v2, l, frame):
if self.type2[v1] == "particle":
l.append("_me.inertia_of_point_mass(" + self.bodies[v1] + ".mass, " + self.bodies[v1] +
".point.pos_from(" + self.symbol_table2[v2] + "), " + frame + ")")
elif self.type2[v1] == "bodies":
# Inertia has been defined about center of mass.
if self.inertia_point[v1] == v1 + "o":
# Asking point is cm as well
if v2 == self.inertia_point[v1]:
l.append(self.symbol_table2[v1] + ".inertia[0]")
# Asking point is not cm
else:
l.append(self.bodies[v1] + ".inertia[0]" + " + " +
"_me.inertia_of_point_mass(" + self.bodies[v1] +
".mass, " + self.bodies[v1] + ".masscenter" +
".pos_from(" + self.symbol_table2[v2] +
"), " + frame + ")")
# Inertia has been defined about another point
else:
# Asking point is the defined point
if v2 == self.inertia_point[v1]:
l.append(self.symbol_table2[v1] + ".inertia[0]")
# Asking point is cm
elif v2 == v1 + "o":
l.append(self.bodies[v1] + ".inertia[0]" + " - " +
"_me.inertia_of_point_mass(" + self.bodies[v1] +
".mass, " + self.bodies[v1] + ".masscenter" +
".pos_from(" + self.symbol_table2[self.inertia_point[v1]] +
"), " + frame + ")")
# Asking point is some other point
else:
l.append(self.bodies[v1] + ".inertia[0]" + " - " +
"_me.inertia_of_point_mass(" + self.bodies[v1] +
".mass, " + self.bodies[v1] + ".masscenter" +
".pos_from(" + self.symbol_table2[self.inertia_point[v1]] +
"), " + frame + ")" + " + " +
"_me.inertia_of_point_mass(" + self.bodies[v1] +
".mass, " + self.bodies[v1] + ".masscenter" +
".pos_from(" + self.symbol_table2[v2] +
"), " + frame + ")")
def processConstants(self, ctx):
# Process constant declarations of the type: Constants F = 3, g = 9.81
name = ctx.ID().getText().lower()
if "=" in ctx.getText():
self.symbol_table.update({name: name})
# self.inputs.update({self.symbol_table[name]: self.getValue(ctx.getChild(2))})
self.write(self.symbol_table[name] + " = " + "_sm.S(" + self.getValue(ctx.getChild(2)) + ")\n")
self.type.update({name: "constants"})
return
# Constants declarations of the type: Constants A, B
else:
if "{" not in ctx.getText():
self.symbol_table[name] = name
self.type[name] = "constants"
# Process constant declarations of the type: Constants C+, D-
if ctx.getChildCount() == 2:
# This is set for declaring nonpositive=True and nonnegative=True
if ctx.getChild(1).getText() == "+":
self.sign[name] = "+"
elif ctx.getChild(1).getText() == "-":
self.sign[name] = "-"
else:
if "{" not in ctx.getText():
self.sign[name] = "o"
# Process constant declarations of the type: Constants K{4}, a{1:2, 1:2}, b{1:2}
if "{" in ctx.getText():
if ":" in ctx.getText():
num1 = int(ctx.INT(0).getText())
num2 = int(ctx.INT(1).getText()) + 1
else:
num1 = 1
num2 = int(ctx.INT(0).getText()) + 1
if ":" in ctx.getText():
if "," in ctx.getText():
num3 = int(ctx.INT(2).getText())
num4 = int(ctx.INT(3).getText()) + 1
for i in range(num1, num2):
for j in range(num3, num4):
self.symbol_table[name + str(i) + str(j)] = name + str(i) + str(j)
self.type[name + str(i) + str(j)] = "constants"
self.var_list.append(name + str(i) + str(j))
self.sign[name + str(i) + str(j)] = "o"
else:
for i in range(num1, num2):
self.symbol_table[name + str(i)] = name + str(i)
self.type[name + str(i)] = "constants"
self.var_list.append(name + str(i))
self.sign[name + str(i)] = "o"
elif "," in ctx.getText():
for i in range(1, int(ctx.INT(0).getText()) + 1):
for j in range(1, int(ctx.INT(1).getText()) + 1):
self.symbol_table[name] = name + str(i) + str(j)
self.type[name + str(i) + str(j)] = "constants"
self.var_list.append(name + str(i) + str(j))
self.sign[name + str(i) + str(j)] = "o"
else:
for i in range(num1, num2):
self.symbol_table[name + str(i)] = name + str(i)
self.type[name + str(i)] = "constants"
self.var_list.append(name + str(i))
self.sign[name + str(i)] = "o"
if "{" not in ctx.getText():
self.var_list.append(name)
def writeConstants(self, ctx):
l1 = list(filter(lambda x: self.sign[x] == "o", self.var_list))
l2 = list(filter(lambda x: self.sign[x] == "+", self.var_list))
l3 = list(filter(lambda x: self.sign[x] == "-", self.var_list))
try:
if self.settings["complex"] == "on":
real = ", real=True"
elif self.settings["complex"] == "off":
real = ""
except Exception:
real = ", real=True"
if l1:
a = ", ".join(l1) + " = " + "_sm.symbols(" + "'" +\
" ".join(l1) + "'" + real + ")\n"
self.write(a)
if l2:
a = ", ".join(l2) + " = " + "_sm.symbols(" + "'" +\
" ".join(l2) + "'" + real + ", nonnegative=True)\n"
self.write(a)
if l3:
a = ", ".join(l3) + " = " + "_sm.symbols(" + "'" + \
" ".join(l3) + "'" + real + ", nonpositive=True)\n"
self.write(a)
self.var_list = []
def processVariables(self, ctx):
# Specified F = x*N1> + y*N2>
name = ctx.ID().getText().lower()
if "=" in ctx.getText():
text = name + "'"*(ctx.getChildCount()-3)
self.write(text + " = " + self.getValue(ctx.expr()) + "\n")
return
# Process variables of the type: Variables qA, qB
if ctx.getChildCount() == 1:
self.symbol_table[name] = name
if self.getValue(ctx.parentCtx.getChild(0)) in ("variable", "specified", "motionvariable", "motionvariable'"):
self.type.update({name: self.getValue(ctx.parentCtx.getChild(0))})
self.var_list.append(name)
self.sign[name] = 0
# Process variables of the type: Variables x', y''
elif "'" in ctx.getText() and "{" not in ctx.getText():
if ctx.getText().count("'") > self.maxDegree:
self.maxDegree = ctx.getText().count("'")
for i in range(ctx.getChildCount()):
self.sign[name + strfunc(i)] = i
self.symbol_table[name + "'"*i] = name + strfunc(i)
if self.getValue(ctx.parentCtx.getChild(0)) in ("variable", "specified", "motionvariable", "motionvariable'"):
self.type.update({name + "'"*i: self.getValue(ctx.parentCtx.getChild(0))})
self.var_list.append(name + strfunc(i))
elif "{" in ctx.getText():
# Process variables of the type: Variales x{3}, y{2}
if "'" in ctx.getText():
dash_count = ctx.getText().count("'")
if dash_count > self.maxDegree:
self.maxDegree = dash_count
if ":" in ctx.getText():
# Variables C{1:2, 1:2}
if "," in ctx.getText():
num1 = int(ctx.INT(0).getText())
num2 = int(ctx.INT(1).getText()) + 1
num3 = int(ctx.INT(2).getText())
num4 = int(ctx.INT(3).getText()) + 1
# Variables C{1:2}
else:
num1 = int(ctx.INT(0).getText())
num2 = int(ctx.INT(1).getText()) + 1
# Variables C{1,3}
elif "," in ctx.getText():
num1 = 1
num2 = int(ctx.INT(0).getText()) + 1
num3 = 1
num4 = int(ctx.INT(1).getText()) + 1
else:
num1 = 1
num2 = int(ctx.INT(0).getText()) + 1
for i in range(num1, num2):
try:
for j in range(num3, num4):
try:
for z in range(dash_count+1):
self.symbol_table.update({name + str(i) + str(j) + "'"*z: name + str(i) + str(j) + strfunc(z)})
if self.getValue(ctx.parentCtx.getChild(0)) in ("variable", "specified", "motionvariable", "motionvariable'"):
self.type.update({name + str(i) + str(j) + "'"*z: self.getValue(ctx.parentCtx.getChild(0))})
self.var_list.append(name + str(i) + str(j) + strfunc(z))
self.sign.update({name + str(i) + str(j) + strfunc(z): z})
if dash_count > self.maxDegree:
self.maxDegree = dash_count
except Exception:
self.symbol_table.update({name + str(i) + str(j): name + str(i) + str(j)})
if self.getValue(ctx.parentCtx.getChild(0)) in ("variable", "specified", "motionvariable", "motionvariable'"):
self.type.update({name + str(i) + str(j): self.getValue(ctx.parentCtx.getChild(0))})
self.var_list.append(name + str(i) + str(j))
self.sign.update({name + str(i) + str(j): 0})
except Exception:
try:
for z in range(dash_count+1):
self.symbol_table.update({name + str(i) + "'"*z: name + str(i) + strfunc(z)})
if self.getValue(ctx.parentCtx.getChild(0)) in ("variable", "specified", "motionvariable", "motionvariable'"):
self.type.update({name + str(i) + "'"*z: self.getValue(ctx.parentCtx.getChild(0))})
self.var_list.append(name + str(i) + strfunc(z))
self.sign.update({name + str(i) + strfunc(z): z})
if dash_count > self.maxDegree:
self.maxDegree = dash_count
except Exception:
self.symbol_table.update({name + str(i): name + str(i)})
if self.getValue(ctx.parentCtx.getChild(0)) in ("variable", "specified", "motionvariable", "motionvariable'"):
self.type.update({name + str(i): self.getValue(ctx.parentCtx.getChild(0))})
self.var_list.append(name + str(i))
self.sign.update({name + str(i): 0})
def writeVariables(self, ctx):
#print(self.sign)
#print(self.symbol_table)
if self.var_list:
for i in range(self.maxDegree+1):
if i == 0:
j = ""
t = ""
else:
j = str(i)
t = ", "
l = []
for k in list(filter(lambda x: self.sign[x] == i, self.var_list)):
if i == 0:
l.append(k)
if i == 1:
l.append(k[:-1])
if i > 1:
l.append(k[:-2])
a = ", ".join(list(filter(lambda x: self.sign[x] == i, self.var_list))) + " = " +\
"_me.dynamicsymbols(" + "'" + " ".join(l) + "'" + t + j + ")\n"
l = []
self.write(a)
self.maxDegree = 0
self.var_list = []
def processImaginary(self, ctx):
name = ctx.ID().getText().lower()
self.symbol_table[name] = name
self.type[name] = "imaginary"
self.var_list.append(name)
def writeImaginary(self, ctx):
a = ", ".join(self.var_list) + " = " + "_sm.symbols(" + "'" + \
" ".join(self.var_list) + "')\n"
b = ", ".join(self.var_list) + " = " + "_sm.I\n"
self.write(a)
self.write(b)
self.var_list = []
if AutolevListener:
class MyListener(AutolevListener): # type: ignore
def __init__(self, include_numeric=False):
# Stores data in tree nodes(tree annotation). Especially useful for expr reconstruction.
self.tree_property = {}
# Stores the declared variables, constants etc as they are declared in Autolev and SymPy
# {"<Autolev symbol>": "<SymPy symbol>"}.
self.symbol_table = collections.OrderedDict()
# Similar to symbol_table. Used for storing Physical entities like Frames, Points,
# Particles, Bodies etc
self.symbol_table2 = collections.OrderedDict()
# Used to store nonpositive, nonnegative etc for constants and number of "'"s (order of diff)
# in variables.
self.sign = {}
# Simple list used as a store to pass around variables between the 'process' and 'write'
# methods.
self.var_list = []
# Stores the type of a declared variable (constants, variables, specifieds etc)
self.type = collections.OrderedDict()
# Similar to self.type. Used for storing the type of Physical entities like Frames, Points,
# Particles, Bodies etc
self.type2 = collections.OrderedDict()
# These lists are used to distinguish matrix, numeric and vector expressions.
self.matrix_expr = []
self.numeric_expr = []
self.vector_expr = []
self.fr_expr = []
self.output_code = []
# Stores the variables and their rhs for substituting upon the Autolev command EXPLICIT.
self.explicit = collections.OrderedDict()
# Write code to import common dependencies.
self.output_code.append("import sympy.physics.mechanics as _me\n")
self.output_code.append("import sympy as _sm\n")
self.output_code.append("import math as m\n")
self.output_code.append("import numpy as _np\n")
self.output_code.append("\n")
# Just a store for the max degree variable in a line.
self.maxDegree = 0
# Stores the input parameters which are then used for codegen and numerical analysis.
self.inputs = collections.OrderedDict()
# Stores the variables which appear in Output Autolev commands.
self.outputs = []
# Stores the settings specified by the user. Ex: Complex on/off, Degrees on/off
self.settings = {}
# Boolean which changes the behaviour of some expression reconstruction
# when parsing Input Autolev commands.
self.in_inputs = False
self.in_outputs = False
# Stores for the physical entities.
self.newtonian = None
self.bodies = collections.OrderedDict()
self.constants = []
self.forces = collections.OrderedDict()
self.q_ind = []
self.q_dep = []
self.u_ind = []
self.u_dep = []
self.kd_eqs = []
self.dependent_variables = []
self.kd_equivalents = collections.OrderedDict()
self.kd_equivalents2 = collections.OrderedDict()
self.kd_eqs_supplied = None
self.kane_type = "no_args"
self.inertia_point = collections.OrderedDict()
self.kane_parsed = False
self.t = False
# PyDy ode code will be included only if this flag is set to True.
self.include_numeric = include_numeric
def write(self, string):
self.output_code.append(string)
def getValue(self, node):
return self.tree_property[node]
def setValue(self, node, value):
self.tree_property[node] = value
def getSymbolTable(self):
return self.symbol_table
def getType(self):
return self.type
def exitVarDecl(self, ctx):
# This event method handles variable declarations. The parse tree node varDecl contains
# one or more varDecl2 nodes. Eg varDecl for 'Constants a{1:2, 1:2}, b{1:2}' has two varDecl2
# nodes(one for a{1:2, 1:2} and one for b{1:2}).
# Variable declarations are processed and stored in the event method exitVarDecl2.
# This stored information is used to write the final SymPy output code in the exitVarDecl event method.
# determine the type of declaration
if self.getValue(ctx.varType()) == "constant":
writeConstants(self, ctx)
elif self.getValue(ctx.varType()) in\
("variable", "motionvariable", "motionvariable'", "specified"):
writeVariables(self, ctx)
elif self.getValue(ctx.varType()) == "imaginary":
writeImaginary(self, ctx)
def exitVarType(self, ctx):
# Annotate the varType tree node with the type of the variable declaration.
name = ctx.getChild(0).getText().lower()
if name[-1] == "s" and name != "bodies":
self.setValue(ctx, name[:-1])
else:
self.setValue(ctx, name)
def exitVarDecl2(self, ctx):
# Variable declarations are processed and stored in the event method exitVarDecl2.
# This stored information is used to write the final SymPy output code in the exitVarDecl event method.
# This is the case for constants, variables, specifieds etc.
# This isn't the case for all types of declarations though. For instance
# Frames A, B, C, N cannot be defined on one line in SymPy. So we do not append A, B, C, N
# to a var_list or use exitVarDecl. exitVarDecl2 directly writes out to the file.
# determine the type of declaration
if self.getValue(ctx.parentCtx.varType()) == "constant":
processConstants(self, ctx)
elif self.getValue(ctx.parentCtx.varType()) in \
("variable", "motionvariable", "motionvariable'", "specified"):
processVariables(self, ctx)
elif self.getValue(ctx.parentCtx.varType()) == "imaginary":
processImaginary(self, ctx)
elif self.getValue(ctx.parentCtx.varType()) in ("frame", "newtonian", "point", "particle", "bodies"):
if "{" in ctx.getText():
if ":" in ctx.getText() and "," not in ctx.getText():
num1 = int(ctx.INT(0).getText())
num2 = int(ctx.INT(1).getText()) + 1
elif ":" not in ctx.getText() and "," in ctx.getText():
num1 = 1
num2 = int(ctx.INT(0).getText()) + 1
num3 = 1
num4 = int(ctx.INT(1).getText()) + 1
elif ":" in ctx.getText() and "," in ctx.getText():
num1 = int(ctx.INT(0).getText())
num2 = int(ctx.INT(1).getText()) + 1
num3 = int(ctx.INT(2).getText())
num4 = int(ctx.INT(3).getText()) + 1
else:
num1 = 1
num2 = int(ctx.INT(0).getText()) + 1
else:
num1 = 1
num2 = 2
for i in range(num1, num2):
try:
for j in range(num3, num4):
declare_phy_entities(self, ctx, self.getValue(ctx.parentCtx.varType()), i, j)
except Exception:
declare_phy_entities(self, ctx, self.getValue(ctx.parentCtx.varType()), i)
# ================== Subrules of parser rule expr (Start) ====================== #
def exitId(self, ctx):
# Tree annotation for ID which is a labeled subrule of the parser rule expr.
# A_C
python_keywords = ["and", "as", "assert", "break", "class", "continue", "def", "del", "elif", "else", "except",\
"exec", "finally", "for", "from", "global", "if", "import", "in", "is", "lambda", "not", "or", "pass", "print",\
"raise", "return", "try", "while", "with", "yield"]
if ctx.ID().getText().lower() in python_keywords:
warnings.warn("Python keywords must not be used as identifiers. Please refer to the list of keywords at https://docs.python.org/2.5/ref/keywords.html",
SyntaxWarning)
if "_" in ctx.ID().getText() and ctx.ID().getText().count('_') == 1:
e1, e2 = ctx.ID().getText().lower().split('_')
try:
if self.type2[e1] == "frame":
e1 = self.symbol_table2[e1]
elif self.type2[e1] == "bodies":
e1 = self.symbol_table2[e1] + "_f"
if self.type2[e2] == "frame":
e2 = self.symbol_table2[e2]
elif self.type2[e2] == "bodies":
e2 = self.symbol_table2[e2] + "_f"
self.setValue(ctx, e1 + ".dcm(" + e2 + ")")
except Exception:
self.setValue(ctx, ctx.ID().getText().lower())
else:
# Reserved constant Pi
if ctx.ID().getText().lower() == "pi":
self.setValue(ctx, "_sm.pi")
self.numeric_expr.append(ctx)
# Reserved variable T (for time)
elif ctx.ID().getText().lower() == "t":
self.setValue(ctx, "_me.dynamicsymbols._t")
if not self.in_inputs and not self.in_outputs:
self.t = True
else:
idText = ctx.ID().getText().lower() + "'"*(ctx.getChildCount() - 1)
if idText in self.type.keys() and self.type[idText] == "matrix":
self.matrix_expr.append(ctx)
if self.in_inputs:
try:
self.setValue(ctx, self.symbol_table[idText])
except Exception:
self.setValue(ctx, idText.lower())
else:
try:
self.setValue(ctx, self.symbol_table[idText])
except Exception:
pass
def exitInt(self, ctx):
# Tree annotation for int which is a labeled subrule of the parser rule expr.
int_text = ctx.INT().getText()
self.setValue(ctx, int_text)
self.numeric_expr.append(ctx)
def exitFloat(self, ctx):
# Tree annotation for float which is a labeled subrule of the parser rule expr.
floatText = ctx.FLOAT().getText()
self.setValue(ctx, floatText)
self.numeric_expr.append(ctx)
def exitAddSub(self, ctx):
# Tree annotation for AddSub which is a labeled subrule of the parser rule expr.
# The subrule is expr = expr (+|-) expr
if ctx.expr(0) in self.matrix_expr or ctx.expr(1) in self.matrix_expr:
self.matrix_expr.append(ctx)
if ctx.expr(0) in self.vector_expr or ctx.expr(1) in self.vector_expr:
self.vector_expr.append(ctx)
if ctx.expr(0) in self.numeric_expr and ctx.expr(1) in self.numeric_expr:
self.numeric_expr.append(ctx)
self.setValue(ctx, self.getValue(ctx.expr(0)) + ctx.getChild(1).getText() +
self.getValue(ctx.expr(1)))
def exitMulDiv(self, ctx):
# Tree annotation for MulDiv which is a labeled subrule of the parser rule expr.
# The subrule is expr = expr (*|/) expr
try:
if ctx.expr(0) in self.vector_expr and ctx.expr(1) in self.vector_expr:
self.setValue(ctx, "_me.outer(" + self.getValue(ctx.expr(0)) + ", " +
self.getValue(ctx.expr(1)) + ")")
else:
if ctx.expr(0) in self.matrix_expr or ctx.expr(1) in self.matrix_expr:
self.matrix_expr.append(ctx)
if ctx.expr(0) in self.vector_expr or ctx.expr(1) in self.vector_expr:
self.vector_expr.append(ctx)
if ctx.expr(0) in self.numeric_expr and ctx.expr(1) in self.numeric_expr:
self.numeric_expr.append(ctx)
self.setValue(ctx, self.getValue(ctx.expr(0)) + ctx.getChild(1).getText() +
self.getValue(ctx.expr(1)))
except Exception:
pass
def exitNegativeOne(self, ctx):
# Tree annotation for negativeOne which is a labeled subrule of the parser rule expr.
self.setValue(ctx, "-1*" + self.getValue(ctx.getChild(1)))
if ctx.getChild(1) in self.matrix_expr:
self.matrix_expr.append(ctx)
if ctx.getChild(1) in self.numeric_expr:
self.numeric_expr.append(ctx)
def exitParens(self, ctx):
# Tree annotation for parens which is a labeled subrule of the parser rule expr.
# The subrule is expr = '(' expr ')'
if ctx.expr() in self.matrix_expr:
self.matrix_expr.append(ctx)
if ctx.expr() in self.vector_expr:
self.vector_expr.append(ctx)
if ctx.expr() in self.numeric_expr:
self.numeric_expr.append(ctx)
self.setValue(ctx, "(" + self.getValue(ctx.expr()) + ")")
def exitExponent(self, ctx):
# Tree annotation for Exponent which is a labeled subrule of the parser rule expr.
# The subrule is expr = expr ^ expr
if ctx.expr(0) in self.matrix_expr or ctx.expr(1) in self.matrix_expr:
self.matrix_expr.append(ctx)
if ctx.expr(0) in self.vector_expr or ctx.expr(1) in self.vector_expr:
self.vector_expr.append(ctx)
if ctx.expr(0) in self.numeric_expr and ctx.expr(1) in self.numeric_expr:
self.numeric_expr.append(ctx)
self.setValue(ctx, self.getValue(ctx.expr(0)) + "**" + self.getValue(ctx.expr(1)))
def exitExp(self, ctx):
s = ctx.EXP().getText()[ctx.EXP().getText().index('E')+1:]
if "-" in s:
s = s[0] + s[1:].lstrip("0")
else:
s = s.lstrip("0")
self.setValue(ctx, ctx.EXP().getText()[:ctx.EXP().getText().index('E')] +
"*10**(" + s + ")")
def exitFunction(self, ctx):
# Tree annotation for function which is a labeled subrule of the parser rule expr.
# The difference between this and FunctionCall is that this is used for non standalone functions
# appearing in expressions and assignments.
# Eg:
# When we come across a standalone function say Expand(E, n:m) then it is categorized as FunctionCall
# which is a parser rule in itself under rule stat. exitFunctionCall() takes care of it and writes to the file.
#
# On the other hand, while we come across E_diff = D(E, y), we annotate the tree node
# of the function D(E, y) with the SymPy equivalent in exitFunction().
# In this case it is the method exitAssignment() that writes the code to the file and not exitFunction().
ch = ctx.getChild(0)
func_name = ch.getChild(0).getText().lower()
# Expand(y, n:m) *
if func_name == "expand":
expr = self.getValue(ch.expr(0))
if ch.expr(0) in self.matrix_expr or (expr in self.type.keys() and self.type[expr] == "matrix"):
self.matrix_expr.append(ctx)
# _sm.Matrix([i.expand() for i in z]).reshape(z.shape[0], z.shape[1])
self.setValue(ctx, "_sm.Matrix([i.expand() for i in " + expr + "])" +
".reshape((" + expr + ").shape[0], " + "(" + expr + ").shape[1])")
else:
self.setValue(ctx, "(" + expr + ")" + "." + "expand()")
# Factor(y, x) *
elif func_name == "factor":
expr = self.getValue(ch.expr(0))
if ch.expr(0) in self.matrix_expr or (expr in self.type.keys() and self.type[expr] == "matrix"):
self.matrix_expr.append(ctx)
self.setValue(ctx, "_sm.Matrix([_sm.factor(i, " + self.getValue(ch.expr(1)) + ") for i in " +
expr + "])" + ".reshape((" + expr + ").shape[0], " + "(" + expr + ").shape[1])")
else:
self.setValue(ctx, "_sm.factor(" + "(" + expr + ")" +
", " + self.getValue(ch.expr(1)) + ")")
# D(y, x)
elif func_name == "d":
expr = self.getValue(ch.expr(0))
if ch.expr(0) in self.matrix_expr or (expr in self.type.keys() and self.type[expr] == "matrix"):
self.matrix_expr.append(ctx)
self.setValue(ctx, "_sm.Matrix([i.diff(" + self.getValue(ch.expr(1)) + ") for i in " +
expr + "])" + ".reshape((" + expr + ").shape[0], " + "(" + expr + ").shape[1])")
else:
if ch.getChildCount() == 8:
frame = self.symbol_table2[ch.expr(2).getText().lower()]
self.setValue(ctx, "(" + expr + ")" + "." + "diff(" + self.getValue(ch.expr(1)) +
", " + frame + ")")
else:
self.setValue(ctx, "(" + expr + ")" + "." + "diff(" +
self.getValue(ch.expr(1)) + ")")
# Dt(y)
elif func_name == "dt":
expr = self.getValue(ch.expr(0))
if ch.expr(0) in self.vector_expr:
text = "dt("
else:
text = "diff(_sm.Symbol('t')"
if ch.expr(0) in self.matrix_expr or (expr in self.type.keys() and self.type[expr] == "matrix"):
self.matrix_expr.append(ctx)
self.setValue(ctx, "_sm.Matrix([i." + text +
") for i in " + expr + "])" +
".reshape((" + expr + ").shape[0], " + "(" + expr + ").shape[1])")
else:
if ch.getChildCount() == 6:
frame = self.symbol_table2[ch.expr(1).getText().lower()]
self.setValue(ctx, "(" + expr + ")" + "." + "dt(" +
frame + ")")
else:
self.setValue(ctx, "(" + expr + ")" + "." + text + ")")
# Explicit(EXPRESS(IMPLICIT>,C))
elif func_name == "explicit":
if ch.expr(0) in self.vector_expr:
self.vector_expr.append(ctx)
expr = self.getValue(ch.expr(0))
if self.explicit.keys():
explicit_list = []
for i in self.explicit.keys():
explicit_list.append(i + ":" + self.explicit[i])
self.setValue(ctx, "(" + expr + ")" + ".subs({" + ", ".join(explicit_list) + "})")
else:
self.setValue(ctx, expr)
# Taylor(y, 0:2, w=a, x=0)
# TODO: Currently only works with symbols. Make it work for dynamicsymbols.
elif func_name == "taylor":
exp = self.getValue(ch.expr(0))
order = self.getValue(ch.expr(1).expr(1))
x = (ch.getChildCount()-6)//2
l = []
for i in range(x):
index = 2 + i
child = ch.expr(index)
l.append(".series(" + self.getValue(child.getChild(0)) +
", " + self.getValue(child.getChild(2)) +
", " + order + ").removeO()")
self.setValue(ctx, "(" + exp + ")" + "".join(l))
# Evaluate(y, a=x, b=2)
elif func_name == "evaluate":
expr = self.getValue(ch.expr(0))
l = []
x = (ch.getChildCount()-4)//2
for i in range(x):
index = 1 + i
child = ch.expr(index)
l.append(self.getValue(child.getChild(0)) + ":" +
self.getValue(child.getChild(2)))
if ch.expr(0) in self.matrix_expr or (expr in self.type.keys() and self.type[expr] == "matrix"):
self.matrix_expr.append(ctx)
self.setValue(ctx, "_sm.Matrix([i.subs({" + ",".join(l) + "}) for i in " +
expr + "])" +
".reshape((" + expr + ").shape[0], " + "(" + expr + ").shape[1])")
else:
if self.explicit:
explicit_list = []
for i in self.explicit.keys():
explicit_list.append(i + ":" + self.explicit[i])
self.setValue(ctx, "(" + expr + ")" + ".subs({" + ",".join(explicit_list) +
"}).subs({" + ",".join(l) + "})")
else:
self.setValue(ctx, "(" + expr + ")" + ".subs({" + ",".join(l) + "})")
# Polynomial([a, b, c], x)
elif func_name == "polynomial":
self.setValue(ctx, "_sm.Poly(" + self.getValue(ch.expr(0)) + ", " +
self.getValue(ch.expr(1)) + ")")
# Roots(Poly, x, 2)
# Roots([1; 2; 3; 4])
elif func_name == "roots":
self.matrix_expr.append(ctx)
expr = self.getValue(ch.expr(0))
if ch.expr(0) in self.matrix_expr or (expr in self.type.keys() and self.type[expr] == "matrix"):
self.setValue(ctx, "[i.evalf() for i in " + "_sm.solve(" +
"_sm.Poly(" + expr + ", " + "x),x)]")
else:
self.setValue(ctx, "[i.evalf() for i in " + "_sm.solve(" +
expr + ", " + self.getValue(ch.expr(1)) + ")]")
# Transpose(A), Inv(A)
elif func_name in ("transpose", "inv", "inverse"):
self.matrix_expr.append(ctx)
if func_name == "transpose":
e = ".T"
elif func_name in ("inv", "inverse"):
e = "**(-1)"
self.setValue(ctx, "(" + self.getValue(ch.expr(0)) + ")" + e)
# Eig(A)
elif func_name == "eig":
# "_sm.Matrix([i.evalf() for i in " +
self.setValue(ctx, "_sm.Matrix([i.evalf() for i in (" +
self.getValue(ch.expr(0)) + ").eigenvals().keys()])")
# Diagmat(n, m, x)
# Diagmat(3, 1)
elif func_name == "diagmat":
self.matrix_expr.append(ctx)
if ch.getChildCount() == 6:
l = []
for i in range(int(self.getValue(ch.expr(0)))):
l.append(self.getValue(ch.expr(1)) + ",")
self.setValue(ctx, "_sm.diag(" + ("".join(l))[:-1] + ")")
elif ch.getChildCount() == 8:
# _sm.Matrix([x if i==j else 0 for i in range(n) for j in range(m)]).reshape(n, m)
n = self.getValue(ch.expr(0))
m = self.getValue(ch.expr(1))
x = self.getValue(ch.expr(2))
self.setValue(ctx, "_sm.Matrix([" + x + " if i==j else 0 for i in range(" +
n + ") for j in range(" + m + ")]).reshape(" + n + ", " + m + ")")
# Cols(A)
# Cols(A, 1)
# Cols(A, 1, 2:4, 3)
elif func_name in ("cols", "rows"):
self.matrix_expr.append(ctx)
if func_name == "cols":
e1 = ".cols"
e2 = ".T."
else:
e1 = ".rows"
e2 = "."
if ch.getChildCount() == 4:
self.setValue(ctx, "(" + self.getValue(ch.expr(0)) + ")" + e1)
elif ch.getChildCount() == 6:
self.setValue(ctx, "(" + self.getValue(ch.expr(0)) + ")" +
e1[:-1] + "(" + str(int(self.getValue(ch.expr(1))) - 1) + ")")
else:
l = []
for i in range(4, ch.getChildCount()):
try:
if ch.getChild(i).getChildCount() > 1 and ch.getChild(i).getChild(1).getText() == ":":
for j in range(int(ch.getChild(i).getChild(0).getText()),
int(ch.getChild(i).getChild(2).getText())+1):
l.append("(" + self.getValue(ch.getChild(2)) + ")" + e2 +
"row(" + str(j-1) + ")")
else:
l.append("(" + self.getValue(ch.getChild(2)) + ")" + e2 +
"row(" + str(int(ch.getChild(i).getText())-1) + ")")
except Exception:
pass
self.setValue(ctx, "_sm.Matrix([" + ",".join(l) + "])")
# Det(A) Trace(A)
elif func_name in ["det", "trace"]:
self.setValue(ctx, "(" + self.getValue(ch.expr(0)) + ")" + "." +
func_name + "()")
# Element(A, 2, 3)
elif func_name == "element":
self.setValue(ctx, "(" + self.getValue(ch.expr(0)) + ")" + "[" +
str(int(self.getValue(ch.expr(1)))-1) + "," +
str(int(self.getValue(ch.expr(2)))-1) + "]")
elif func_name in \
["cos", "sin", "tan", "cosh", "sinh", "tanh", "acos", "asin", "atan",
"log", "exp", "sqrt", "factorial", "floor", "sign"]:
self.setValue(ctx, "_sm." + func_name + "(" + self.getValue(ch.expr(0)) + ")")
elif func_name == "ceil":
self.setValue(ctx, "_sm.ceiling" + "(" + self.getValue(ch.expr(0)) + ")")
elif func_name == "sqr":
self.setValue(ctx, "(" + self.getValue(ch.expr(0)) +
")" + "**2")
elif func_name == "log10":
self.setValue(ctx, "_sm.log" +
"(" + self.getValue(ch.expr(0)) + ", 10)")
elif func_name == "atan2":
self.setValue(ctx, "_sm.atan2" + "(" + self.getValue(ch.expr(0)) + ", " +
self.getValue(ch.expr(1)) + ")")
elif func_name in ["int", "round"]:
self.setValue(ctx, func_name +
"(" + self.getValue(ch.expr(0)) + ")")
elif func_name == "abs":
self.setValue(ctx, "_sm.Abs(" + self.getValue(ch.expr(0)) + ")")
elif func_name in ["max", "min"]:
# max(x, y, z)
l = []
for i in range(1, ch.getChildCount()):
if ch.getChild(i) in self.tree_property.keys():
l.append(self.getValue(ch.getChild(i)))
elif ch.getChild(i).getText() in [",", "(", ")"]:
l.append(ch.getChild(i).getText())
self.setValue(ctx, "_sm." + ch.getChild(0).getText().capitalize() + "".join(l))
# Coef(y, x)
elif func_name == "coef":
#A41_A53=COEF([RHS(U4);RHS(U5)],[U1,U2,U3])
if ch.expr(0) in self.matrix_expr and ch.expr(1) in self.matrix_expr:
icount = jcount = 0
for i in range(ch.expr(0).getChild(0).getChildCount()):
try:
ch.expr(0).getChild(0).getChild(i).getRuleIndex()
icount+=1
except Exception:
pass
for j in range(ch.expr(1).getChild(0).getChildCount()):
try:
ch.expr(1).getChild(0).getChild(j).getRuleIndex()
jcount+=1
except Exception:
pass
l = []
for i in range(icount):
for j in range(jcount):
# a41_a53[i,j] = u4.expand().coeff(u1)
l.append(self.getValue(ch.expr(0).getChild(0).expr(i)) + ".expand().coeff("
+ self.getValue(ch.expr(1).getChild(0).expr(j)) + ")")
self.setValue(ctx, "_sm.Matrix([" + ", ".join(l) + "]).reshape(" + str(icount) + ", " + str(jcount) + ")")
else:
self.setValue(ctx, "(" + self.getValue(ch.expr(0)) +
")" + ".expand().coeff(" + self.getValue(ch.expr(1)) + ")")
# Exclude(y, x) Include(y, x)
elif func_name in ("exclude", "include"):
if func_name == "exclude":
e = "0"
else:
e = "1"
expr = self.getValue(ch.expr(0))
if ch.expr(0) in self.matrix_expr or (expr in self.type.keys() and self.type[expr] == "matrix"):
self.matrix_expr.append(ctx)
self.setValue(ctx, "_sm.Matrix([i.collect(" + self.getValue(ch.expr(1)) + "])" +
".coeff(" + self.getValue(ch.expr(1)) + "," + e + ")" + "for i in " + expr + ")" +
".reshape((" + expr + ").shape[0], " + "(" + expr + ").shape[1])")
else:
self.setValue(ctx, "(" + expr +
")" + ".collect(" + self.getValue(ch.expr(1)) + ")" +
".coeff(" + self.getValue(ch.expr(1)) + "," + e + ")")
# RHS(y)
elif func_name == "rhs":
self.setValue(ctx, self.explicit[self.getValue(ch.expr(0))])
# Arrange(y, n, x) *
elif func_name == "arrange":
expr = self.getValue(ch.expr(0))
if ch.expr(0) in self.matrix_expr or (expr in self.type.keys() and self.type[expr] == "matrix"):
self.matrix_expr.append(ctx)
self.setValue(ctx, "_sm.Matrix([i.collect(" + self.getValue(ch.expr(2)) +
")" + "for i in " + expr + "])"+
".reshape((" + expr + ").shape[0], " + "(" + expr + ").shape[1])")
else:
self.setValue(ctx, "(" + expr +
")" + ".collect(" + self.getValue(ch.expr(2)) + ")")
# Replace(y, sin(x)=3)
elif func_name == "replace":
l = []
for i in range(1, ch.getChildCount()):
try:
if ch.getChild(i).getChild(1).getText() == "=":
l.append(self.getValue(ch.getChild(i).getChild(0)) +
":" + self.getValue(ch.getChild(i).getChild(2)))
except Exception:
pass
expr = self.getValue(ch.expr(0))
if ch.expr(0) in self.matrix_expr or (expr in self.type.keys() and self.type[expr] == "matrix"):
self.matrix_expr.append(ctx)
self.setValue(ctx, "_sm.Matrix([i.subs({" + ",".join(l) + "}) for i in " +
expr + "])" +
".reshape((" + expr + ").shape[0], " + "(" + expr + ").shape[1])")
else:
self.setValue(ctx, "(" + self.getValue(ch.expr(0)) + ")" +
".subs({" + ",".join(l) + "})")
# Dot(Loop>, N1>)
elif func_name == "dot":
l = []
num = (ch.expr(1).getChild(0).getChildCount()-1)//2
if ch.expr(1) in self.matrix_expr:
for i in range(num):
l.append("_me.dot(" + self.getValue(ch.expr(0)) + ", " + self.getValue(ch.expr(1).getChild(0).expr(i)) + ")")
self.setValue(ctx, "_sm.Matrix([" + ",".join(l) + "]).reshape(" + str(num) + ", " + "1)")
else:
self.setValue(ctx, "_me.dot(" + self.getValue(ch.expr(0)) + ", " + self.getValue(ch.expr(1)) + ")")
# Cross(w_A_N>, P_NA_AB>)
elif func_name == "cross":
self.vector_expr.append(ctx)
self.setValue(ctx, "_me.cross(" + self.getValue(ch.expr(0)) + ", " + self.getValue(ch.expr(1)) + ")")
# Mag(P_O_Q>)
elif func_name == "mag":
self.setValue(ctx, self.getValue(ch.expr(0)) + "." + "magnitude()")
# MATRIX(A, I_R>>)
elif func_name == "matrix":
if self.type2[ch.expr(0).getText().lower()] == "frame":
text = ""
elif self.type2[ch.expr(0).getText().lower()] == "bodies":
text = "_f"
self.setValue(ctx, "(" + self.getValue(ch.expr(1)) + ")" + ".to_matrix(" +
self.symbol_table2[ch.expr(0).getText().lower()] + text + ")")
# VECTOR(A, ROWS(EIGVECS,1))
elif func_name == "vector":
if self.type2[ch.expr(0).getText().lower()] == "frame":
text = ""
elif self.type2[ch.expr(0).getText().lower()] == "bodies":
text = "_f"
v = self.getValue(ch.expr(1))
f = self.symbol_table2[ch.expr(0).getText().lower()] + text
self.setValue(ctx, v + "[0]*" + f + ".x +" + v + "[1]*" + f + ".y +" +
v + "[2]*" + f + ".z")
# Express(A2>, B)
# Here I am dealing with all the Inertia commands as I expect the users to use Inertia
# commands only with Express because SymPy needs the Reference frame to be specified unlike Autolev.
elif func_name == "express":
self.vector_expr.append(ctx)
if self.type2[ch.expr(1).getText().lower()] == "frame":
frame = self.symbol_table2[ch.expr(1).getText().lower()]
else:
frame = self.symbol_table2[ch.expr(1).getText().lower()] + "_f"
if ch.expr(0).getText().lower() == "1>>":
self.setValue(ctx, "_me.inertia(" + frame + ", 1, 1, 1)")
elif '_' in ch.expr(0).getText().lower() and ch.expr(0).getText().lower().count('_') == 2\
and ch.expr(0).getText().lower()[0] == "i" and ch.expr(0).getText().lower()[-2:] == ">>":
v1 = ch.expr(0).getText().lower()[:-2].split('_')[1]
v2 = ch.expr(0).getText().lower()[:-2].split('_')[2]
l = []
inertia_func(self, v1, v2, l, frame)
self.setValue(ctx, " + ".join(l))
elif ch.expr(0).getChild(0).getChild(0).getText().lower() == "inertia":
if ch.expr(0).getChild(0).getChildCount() == 4:
l = []
v2 = ch.expr(0).getChild(0).ID(0).getText().lower()
for v1 in self.bodies:
inertia_func(self, v1, v2, l, frame)
self.setValue(ctx, " + ".join(l))
else:
l = []
l2 = []
v2 = ch.expr(0).getChild(0).ID(0).getText().lower()
for i in range(1, (ch.expr(0).getChild(0).getChildCount()-2)//2):
l2.append(ch.expr(0).getChild(0).ID(i).getText().lower())
for v1 in l2:
inertia_func(self, v1, v2, l, frame)
self.setValue(ctx, " + ".join(l))
else:
self.setValue(ctx, "(" + self.getValue(ch.expr(0)) + ")" + ".express(" +
self.symbol_table2[ch.expr(1).getText().lower()] + ")")
# CM(P)
elif func_name == "cm":
if self.type2[ch.expr(0).getText().lower()] == "point":
text = ""
else:
text = ".point"
if ch.getChildCount() == 4:
self.setValue(ctx, "_me.functions.center_of_mass(" + self.symbol_table2[ch.expr(0).getText().lower()] +
text + "," + ", ".join(self.bodies.values()) + ")")
else:
bodies = []
for i in range(1, (ch.getChildCount()-1)//2):
bodies.append(self.symbol_table2[ch.expr(i).getText().lower()])
self.setValue(ctx, "_me.functions.center_of_mass(" + self.symbol_table2[ch.expr(0).getText().lower()] +
text + "," + ", ".join(bodies) + ")")
# PARTIALS(V_P1_E>,U1)
elif func_name == "partials":
speeds = []
for i in range(1, (ch.getChildCount()-1)//2):
if self.kd_equivalents2:
speeds.append(self.kd_equivalents2[self.symbol_table[ch.expr(i).getText().lower()]])
else:
speeds.append(self.symbol_table[ch.expr(i).getText().lower()])
v1, v2, v3 = ch.expr(0).getText().lower().replace(">","").split('_')
if self.type2[v2] == "point":
point = self.symbol_table2[v2]
elif self.type2[v2] == "particle":
point = self.symbol_table2[v2] + ".point"
frame = self.symbol_table2[v3]
self.setValue(ctx, point + ".partial_velocity(" + frame + ", " + ",".join(speeds) + ")")
# UnitVec(A1>+A2>+A3>)
elif func_name == "unitvec":
self.setValue(ctx, "(" + self.getValue(ch.expr(0)) + ")" + ".normalize()")
# Units(deg, rad)
elif func_name == "units":
if ch.expr(0).getText().lower() == "deg" and ch.expr(1).getText().lower() == "rad":
factor = 0.0174533
elif ch.expr(0).getText().lower() == "rad" and ch.expr(1).getText().lower() == "deg":
factor = 57.2958
self.setValue(ctx, str(factor))
# Mass(A)
elif func_name == "mass":
l = []
try:
ch.ID(0).getText().lower()
for i in range((ch.getChildCount()-1)//2):
l.append(self.symbol_table2[ch.ID(i).getText().lower()] + ".mass")
self.setValue(ctx, "+".join(l))
except Exception:
for i in self.bodies.keys():
l.append(self.bodies[i] + ".mass")
self.setValue(ctx, "+".join(l))
# Fr() FrStar()
# _me.KanesMethod(n, q_ind, u_ind, kd, velocity_constraints).kanes_equations(pl, fl)[0]
elif func_name in ["fr", "frstar"]:
if not self.kane_parsed:
if self.kd_eqs:
for i in self.kd_eqs:
self.q_ind.append(self.symbol_table[i.strip().split('-')[0].replace("'","")])
self.u_ind.append(self.symbol_table[i.strip().split('-')[1].replace("'","")])
for i in range(len(self.kd_eqs)):
self.kd_eqs[i] = self.symbol_table[self.kd_eqs[i].strip().split('-')[0]] + " - " +\
self.symbol_table[self.kd_eqs[i].strip().split('-')[1]]
# Do all of this if kd_eqs are not specified
if not self.kd_eqs:
self.kd_eqs_supplied = False
self.matrix_expr.append(ctx)
for i in self.type.keys():
if self.type[i] == "motionvariable":
if self.sign[self.symbol_table[i.lower()]] == 0:
self.q_ind.append(self.symbol_table[i.lower()])
elif self.sign[self.symbol_table[i.lower()]] == 1:
name = "u_" + self.symbol_table[i.lower()]
self.symbol_table.update({name: name})
self.write(name + " = " + "_me.dynamicsymbols('" + name + "')\n")
if self.symbol_table[i.lower()] not in self.dependent_variables:
self.u_ind.append(name)
self.kd_equivalents.update({name: self.symbol_table[i.lower()]})
else:
self.u_dep.append(name)
self.kd_equivalents.update({name: self.symbol_table[i.lower()]})
for i in self.kd_equivalents.keys():
self.kd_eqs.append(self.kd_equivalents[i] + "-" + i)
if not self.u_ind and not self.kd_eqs:
self.u_ind = self.q_ind.copy()
self.q_ind = []
# deal with velocity constraints
if self.dependent_variables:
for i in self.dependent_variables:
self.u_dep.append(i)
if i in self.u_ind:
self.u_ind.remove(i)
self.u_dep[:] = [i for i in self.u_dep if i not in self.kd_equivalents.values()]
force_list = []
for i in self.forces.keys():
force_list.append("(" + i + "," + self.forces[i] + ")")
if self.u_dep:
u_dep_text = ", u_dependent=[" + ", ".join(self.u_dep) + "]"
else:
u_dep_text = ""
if self.dependent_variables:
velocity_constraints_text = ", velocity_constraints = velocity_constraints"
else:
velocity_constraints_text = ""
if ctx.parentCtx not in self.fr_expr:
self.write("kd_eqs = [" + ", ".join(self.kd_eqs) + "]\n")
self.write("forceList = " + "[" + ", ".join(force_list) + "]\n")
self.write("kane = _me.KanesMethod(" + self.newtonian + ", " + "q_ind=[" +
",".join(self.q_ind) + "], " + "u_ind=[" +
", ".join(self.u_ind) + "]" + u_dep_text + ", " +
"kd_eqs = kd_eqs" + velocity_constraints_text + ")\n")
self.write("fr, frstar = kane." + "kanes_equations([" +
", ".join(self.bodies.values()) + "], forceList)\n")
self.fr_expr.append(ctx.parentCtx)
self.kane_parsed = True
self.setValue(ctx, func_name)
def exitMatrices(self, ctx):
# Tree annotation for Matrices which is a labeled subrule of the parser rule expr.
# MO = [a, b; c, d]
# we generate _sm.Matrix([a, b, c, d]).reshape(2, 2)
# The reshape values are determined by counting the "," and ";" in the Autolev matrix
# Eg:
# [1, 2, 3; 4, 5, 6; 7, 8, 9; 10, 11, 12]
# semicolon_count = 3 and rows = 3+1 = 4
# comma_count = 8 and cols = 8/rows + 1 = 8/4 + 1 = 3
# TODO** Parse block matrices
self.matrix_expr.append(ctx)
l = []
semicolon_count = 0
comma_count = 0
for i in range(ctx.matrix().getChildCount()):
child = ctx.matrix().getChild(i)
if child == AutolevParser.ExprContext:
l.append(self.getValue(child))
elif child.getText() == ";":
semicolon_count += 1
l.append(",")
elif child.getText() == ",":
comma_count += 1
l.append(",")
else:
try:
try:
l.append(self.getValue(child))
except Exception:
l.append(self.symbol_table[child.getText().lower()])
except Exception:
l.append(child.getText().lower())
num_of_rows = semicolon_count + 1
num_of_cols = (comma_count//num_of_rows) + 1
self.setValue(ctx, "_sm.Matrix(" + "".join(l) + ")" + ".reshape(" +
str(num_of_rows) + ", " + str(num_of_cols) + ")")
def exitVectorOrDyadic(self, ctx):
self.vector_expr.append(ctx)
ch = ctx.vec()
if ch.getChild(0).getText() == "0>":
self.setValue(ctx, "0")
elif ch.getChild(0).getText() == "1>>":
self.setValue(ctx, "1>>")
elif "_" in ch.ID().getText() and ch.ID().getText().count('_') == 2:
vec_text = ch.getText().lower()
v1, v2, v3 = ch.ID().getText().lower().split('_')
if v1 == "p":
if self.type2[v2] == "point":
e2 = self.symbol_table2[v2]
elif self.type2[v2] == "particle":
e2 = self.symbol_table2[v2] + ".point"
if self.type2[v3] == "point":
e3 = self.symbol_table2[v3]
elif self.type2[v3] == "particle":
e3 = self.symbol_table2[v3] + ".point"
get_vec = e3 + ".pos_from(" + e2 + ")"
self.setValue(ctx, get_vec)
elif v1 in ("w", "alf"):
if v1 == "w":
text = ".ang_vel_in("
elif v1 == "alf":
text = ".ang_acc_in("
if self.type2[v2] == "bodies":
e2 = self.symbol_table2[v2] + "_f"
elif self.type2[v2] == "frame":
e2 = self.symbol_table2[v2]
if self.type2[v3] == "bodies":
e3 = self.symbol_table2[v3] + "_f"
elif self.type2[v3] == "frame":
e3 = self.symbol_table2[v3]
get_vec = e2 + text + e3 + ")"
self.setValue(ctx, get_vec)
elif v1 in ("v", "a"):
if v1 == "v":
text = ".vel("
elif v1 == "a":
text = ".acc("
if self.type2[v2] == "point":
e2 = self.symbol_table2[v2]
elif self.type2[v2] == "particle":
e2 = self.symbol_table2[v2] + ".point"
get_vec = e2 + text + self.symbol_table2[v3] + ")"
self.setValue(ctx, get_vec)
else:
self.setValue(ctx, vec_text.replace(">", ""))
else:
vec_text = ch.getText().lower()
name = self.symbol_table[vec_text]
self.setValue(ctx, name)
def exitIndexing(self, ctx):
if ctx.getChildCount() == 4:
try:
int_text = str(int(self.getValue(ctx.getChild(2))) - 1)
except Exception:
int_text = self.getValue(ctx.getChild(2)) + " - 1"
self.setValue(ctx, ctx.ID().getText().lower() + "[" + int_text + "]")
elif ctx.getChildCount() == 6:
try:
int_text1 = str(int(self.getValue(ctx.getChild(2))) - 1)
except Exception:
int_text1 = self.getValue(ctx.getChild(2)) + " - 1"
try:
int_text2 = str(int(self.getValue(ctx.getChild(4))) - 1)
except Exception:
int_text2 = self.getValue(ctx.getChild(2)) + " - 1"
self.setValue(ctx, ctx.ID().getText().lower() + "[" + int_text1 + ", " + int_text2 + "]")
# ================== Subrules of parser rule expr (End) ====================== #
def exitRegularAssign(self, ctx):
# Handle assignments of type ID = expr
if ctx.equals().getText() in ["=", "+=", "-=", "*=", "/="]:
equals = ctx.equals().getText()
elif ctx.equals().getText() == ":=":
equals = " = "
elif ctx.equals().getText() == "^=":
equals = "**="
try:
a = ctx.ID().getText().lower() + "'"*ctx.diff().getText().count("'")
except Exception:
a = ctx.ID().getText().lower()
if a in self.type.keys() and self.type[a] in ("motionvariable", "motionvariable'") and\
self.type[ctx.expr().getText().lower()] in ("motionvariable", "motionvariable'"):
b = ctx.expr().getText().lower()
if "'" in b and "'" not in a:
a, b = b, a
if not self.kane_parsed:
self.kd_eqs.append(a + "-" + b)
self.kd_equivalents.update({self.symbol_table[a]:
self.symbol_table[b]})
self.kd_equivalents2.update({self.symbol_table[b]:
self.symbol_table[a]})
if a in self.symbol_table.keys() and a in self.type.keys() and self.type[a] in ("variable", "motionvariable"):
self.explicit.update({self.symbol_table[a]: self.getValue(ctx.expr())})
else:
if ctx.expr() in self.matrix_expr:
self.type.update({a: "matrix"})
try:
b = self.symbol_table[a]
except KeyError:
self.symbol_table[a] = a
if "_" in a and a.count("_") == 1:
e1, e2 = a.split('_')
if e1 in self.type2.keys() and self.type2[e1] in ("frame", "bodies")\
and e2 in self.type2.keys() and self.type2[e2] in ("frame", "bodies"):
if self.type2[e1] == "bodies":
t1 = "_f"
else:
t1 = ""
if self.type2[e2] == "bodies":
t2 = "_f"
else:
t2 = ""
self.write(self.symbol_table2[e2] + t2 + ".orient(" + self.symbol_table2[e1] +
t1 + ", 'DCM', " + self.getValue(ctx.expr()) + ")\n")
else:
self.write(self.symbol_table[a] + " " + equals + " " +
self.getValue(ctx.expr()) + "\n")
else:
self.write(self.symbol_table[a] + " " + equals + " " +
self.getValue(ctx.expr()) + "\n")
def exitIndexAssign(self, ctx):
# Handle assignments of type ID[index] = expr
if ctx.equals().getText() in ["=", "+=", "-=", "*=", "/="]:
equals = ctx.equals().getText()
elif ctx.equals().getText() == ":=":
equals = " = "
elif ctx.equals().getText() == "^=":
equals = "**="
text = ctx.ID().getText().lower()
self.type.update({text: "matrix"})
# Handle assignments of type ID[2] = expr
if ctx.index().getChildCount() == 1:
if ctx.index().getChild(0).getText() == "1":
self.type.update({text: "matrix"})
self.symbol_table.update({text: text})
self.write(text + " = " + "_sm.Matrix([[0]])\n")
self.write(text + "[0] = " + self.getValue(ctx.expr()) + "\n")
else:
# m = m.row_insert(m.shape[0], _sm.Matrix([[0]]))
self.write(text + " = " + text +
".row_insert(" + text + ".shape[0]" + ", " + "_sm.Matrix([[0]])" + ")\n")
self.write(text + "[" + text + ".shape[0]-1" + "] = " + self.getValue(ctx.expr()) + "\n")
# Handle assignments of type ID[2, 2] = expr
elif ctx.index().getChildCount() == 3:
l = []
try:
l.append(str(int(self.getValue(ctx.index().getChild(0)))-1))
except Exception:
l.append(self.getValue(ctx.index().getChild(0)) + "-1")
l.append(",")
try:
l.append(str(int(self.getValue(ctx.index().getChild(2)))-1))
except Exception:
l.append(self.getValue(ctx.index().getChild(2)) + "-1")
self.write(self.symbol_table[ctx.ID().getText().lower()] +
"[" + "".join(l) + "]" + " " + equals + " " + self.getValue(ctx.expr()) + "\n")
def exitVecAssign(self, ctx):
# Handle assignments of the type vec = expr
ch = ctx.vec()
vec_text = ch.getText().lower()
if "_" in ch.ID().getText():
num = ch.ID().getText().count('_')
if num == 2:
v1, v2, v3 = ch.ID().getText().lower().split('_')
if v1 == "p":
if self.type2[v2] == "point":
e2 = self.symbol_table2[v2]
elif self.type2[v2] == "particle":
e2 = self.symbol_table2[v2] + ".point"
if self.type2[v3] == "point":
e3 = self.symbol_table2[v3]
elif self.type2[v3] == "particle":
e3 = self.symbol_table2[v3] + ".point"
# ab.set_pos(na, la*a.x)
self.write(e3 + ".set_pos(" + e2 + ", " + self.getValue(ctx.expr()) + ")\n")
elif v1 in ("w", "alf"):
if v1 == "w":
text = ".set_ang_vel("
elif v1 == "alf":
text = ".set_ang_acc("
# a.set_ang_vel(n, qad*a.z)
if self.type2[v2] == "bodies":
e2 = self.symbol_table2[v2] + "_f"
else:
e2 = self.symbol_table2[v2]
if self.type2[v3] == "bodies":
e3 = self.symbol_table2[v3] + "_f"
else:
e3 = self.symbol_table2[v3]
self.write(e2 + text + e3 + ", " + self.getValue(ctx.expr()) + ")\n")
elif v1 in ("v", "a"):
if v1 == "v":
text = ".set_vel("
elif v1 == "a":
text = ".set_acc("
if self.type2[v2] == "point":
e2 = self.symbol_table2[v2]
elif self.type2[v2] == "particle":
e2 = self.symbol_table2[v2] + ".point"
self.write(e2 + text + self.symbol_table2[v3] +
", " + self.getValue(ctx.expr()) + ")\n")
elif v1 == "i":
if v2 in self.type2.keys() and self.type2[v2] == "bodies":
self.write(self.symbol_table2[v2] + ".inertia = (" + self.getValue(ctx.expr()) +
", " + self.symbol_table2[v3] + ")\n")
self.inertia_point.update({v2: v3})
elif v2 in self.type2.keys() and self.type2[v2] == "particle":
self.write(ch.ID().getText().lower() + " = " + self.getValue(ctx.expr()) + "\n")
else:
self.write(ch.ID().getText().lower() + " = " + self.getValue(ctx.expr()) + "\n")
else:
self.write(ch.ID().getText().lower() + " = " + self.getValue(ctx.expr()) + "\n")
elif num == 1:
v1, v2 = ch.ID().getText().lower().split('_')
if v1 in ("force", "torque"):
if self.type2[v2] in ("point", "frame"):
e2 = self.symbol_table2[v2]
elif self.type2[v2] == "particle":
e2 = self.symbol_table2[v2] + ".point"
self.symbol_table.update({vec_text: ch.ID().getText().lower()})
if e2 in self.forces.keys():
self.forces[e2] = self.forces[e2] + " + " + self.getValue(ctx.expr())
else:
self.forces.update({e2: self.getValue(ctx.expr())})
self.write(ch.ID().getText().lower() + " = " + self.forces[e2] + "\n")
else:
name = ch.ID().getText().lower()
self.symbol_table.update({vec_text: name})
self.write(ch.ID().getText().lower() + " = " + self.getValue(ctx.expr()) + "\n")
else:
name = ch.ID().getText().lower()
self.symbol_table.update({vec_text: name})
self.write(name + " " + ctx.getChild(1).getText() + " " + self.getValue(ctx.expr()) + "\n")
else:
name = ch.ID().getText().lower()
self.symbol_table.update({vec_text: name})
self.write(name + " " + ctx.getChild(1).getText() + " " + self.getValue(ctx.expr()) + "\n")
def enterInputs2(self, ctx):
self.in_inputs = True
# Inputs
def exitInputs2(self, ctx):
# Stores numerical values given by the input command which
# are used for codegen and numerical analysis.
if ctx.getChildCount() == 3:
try:
self.inputs.update({self.symbol_table[ctx.id_diff().getText().lower()]: self.getValue(ctx.expr(0))})
except Exception:
self.inputs.update({ctx.id_diff().getText().lower(): self.getValue(ctx.expr(0))})
elif ctx.getChildCount() == 4:
try:
self.inputs.update({self.symbol_table[ctx.id_diff().getText().lower()]:
(self.getValue(ctx.expr(0)), self.getValue(ctx.expr(1)))})
except Exception:
self.inputs.update({ctx.id_diff().getText().lower():
(self.getValue(ctx.expr(0)), self.getValue(ctx.expr(1)))})
self.in_inputs = False
def enterOutputs(self, ctx):
self.in_outputs = True
def exitOutputs(self, ctx):
self.in_outputs = False
def exitOutputs2(self, ctx):
try:
if "[" in ctx.expr(1).getText():
self.outputs.append(self.symbol_table[ctx.expr(0).getText().lower()] +
ctx.expr(1).getText().lower())
else:
self.outputs.append(self.symbol_table[ctx.expr(0).getText().lower()])
except Exception:
pass
# Code commands
def exitCodegen(self, ctx):
# Handles the CODE() command ie the solvers and the codgen part.
# Uses linsolve for the algebraic solvers and nsolve for non linear solvers.
if ctx.functionCall().getChild(0).getText().lower() == "algebraic":
matrix_name = self.getValue(ctx.functionCall().expr(0))
e = []
d = []
for i in range(1, (ctx.functionCall().getChildCount()-2)//2):
a = self.getValue(ctx.functionCall().expr(i))
e.append(a)
for i in self.inputs.keys():
d.append(i + ":" + self.inputs[i])
self.write(matrix_name + "_list" + " = " + "[]\n")
self.write("for i in " + matrix_name + ": " + matrix_name +
"_list" + ".append(i.subs({" + ", ".join(d) + "}))\n")
self.write("print(_sm.linsolve(" + matrix_name + "_list" + ", " + ",".join(e) + "))\n")
elif ctx.functionCall().getChild(0).getText().lower() == "nonlinear":
e = []
d = []
guess = []
for i in range(1, (ctx.functionCall().getChildCount()-2)//2):
a = self.getValue(ctx.functionCall().expr(i))
e.append(a)
#print(self.inputs)
for i in self.inputs.keys():
if i in self.symbol_table.keys():
if type(self.inputs[i]) is tuple:
j, z = self.inputs[i]
else:
j = self.inputs[i]
z = ""
if i not in e:
if z == "deg":
d.append(i + ":" + "_np.deg2rad(" + j + ")")
else:
d.append(i + ":" + j)
else:
if z == "deg":
guess.append("_np.deg2rad(" + j + ")")
else:
guess.append(j)
self.write("matrix_list" + " = " + "[]\n")
self.write("for i in " + self.getValue(ctx.functionCall().expr(0)) + ":")
self.write("matrix_list" + ".append(i.subs({" + ", ".join(d) + "}))\n")
self.write("print(_sm.nsolve(matrix_list," + "(" + ",".join(e) + ")" +
",(" + ",".join(guess) + ")" + "))\n")
elif ctx.functionCall().getChild(0).getText().lower() in ["ode", "dynamics"] and self.include_numeric:
if self.kane_type == "no_args":
for i in self.symbol_table.keys():
try:
if self.type[i] == "constants" or self.type[self.symbol_table[i]] == "constants":
self.constants.append(self.symbol_table[i])
except Exception:
pass
q_add_u = self.q_ind + self.q_dep + self.u_ind + self.u_dep
x0 = []
for i in q_add_u:
try:
if i in self.inputs.keys():
if type(self.inputs[i]) is tuple:
if self.inputs[i][1] == "deg":
x0.append(i + ":" + "_np.deg2rad(" + self.inputs[i][0] + ")")
else:
x0.append(i + ":" + self.inputs[i][0])
else:
x0.append(i + ":" + self.inputs[i])
elif self.kd_equivalents[i] in self.inputs.keys():
if type(self.inputs[self.kd_equivalents[i]]) is tuple:
x0.append(i + ":" + self.inputs[self.kd_equivalents[i]][0])
else:
x0.append(i + ":" + self.inputs[self.kd_equivalents[i]])
except Exception:
pass
# numerical constants
numerical_constants = []
for i in self.constants:
if i in self.inputs.keys():
if type(self.inputs[i]) is tuple:
numerical_constants.append(self.inputs[i][0])
else:
numerical_constants.append(self.inputs[i])
# t = linspace
t_final = self.inputs["tfinal"]
integ_stp = self.inputs["integstp"]
self.write("from pydy.system import System\n")
const_list = []
if numerical_constants:
for i in range(len(self.constants)):
const_list.append(self.constants[i] + ":" + numerical_constants[i])
specifieds = []
if self.t:
specifieds.append("_me.dynamicsymbols('t')" + ":" + "lambda x, t: t")
for i in self.inputs:
if i in self.symbol_table.keys() and self.symbol_table[i] not in\
self.constants + self.q_ind + self.q_dep + self.u_ind + self.u_dep:
specifieds.append(self.symbol_table[i] + ":" + self.inputs[i])
self.write("sys = System(kane, constants = {" + ", ".join(const_list) + "},\n" +
"specifieds={" + ", ".join(specifieds) + "},\n" +
"initial_conditions={" + ", ".join(x0) + "},\n" +
"times = _np.linspace(0.0, " + str(t_final) + ", " + str(t_final) +
"/" + str(integ_stp) + "))\n\ny=sys.integrate()\n")
# For outputs other than qs and us.
other_outputs = []
for i in self.outputs:
if i not in q_add_u:
if "[" in i:
other_outputs.append((i[:-3] + i[-2], i[:-3] + "[" + str(int(i[-2])-1) + "]"))
else:
other_outputs.append((i, i))
for i in other_outputs:
self.write(i[0] + "_out" + " = " + "[]\n")
if other_outputs:
self.write("for i in y:\n")
self.write(" q_u_dict = dict(zip(sys.coordinates+sys.speeds, i))\n")
for i in other_outputs:
self.write(" "*4 + i[0] + "_out" + ".append(" + i[1] + ".subs(q_u_dict)" +
".subs(sys.constants).evalf())\n")
# Standalone function calls (used for dual functions)
def exitFunctionCall(self, ctx):
# Basically deals with standalone function calls ie functions which are not a part of
# expressions and assignments. Autolev Dual functions can both appear in standalone
# function calls and also on the right hand side as part of expr or assignment.
# Dual functions are indicated by a * in the comments below
# Checks if the function is a statement on its own
if ctx.parentCtx.getRuleIndex() == AutolevParser.RULE_stat:
func_name = ctx.getChild(0).getText().lower()
# Expand(E, n:m) *
if func_name == "expand":
# If the first argument is a pre declared variable.
expr = self.getValue(ctx.expr(0))
symbol = self.symbol_table[ctx.expr(0).getText().lower()]
if ctx.expr(0) in self.matrix_expr or (expr in self.type.keys() and self.type[expr] == "matrix"):
self.write(symbol + " = " + "_sm.Matrix([i.expand() for i in " + expr + "])" +
".reshape((" + expr + ").shape[0], " + "(" + expr + ").shape[1])\n")
else:
self.write(symbol + " = " + symbol + "." + "expand()\n")
# Factor(E, x) *
elif func_name == "factor":
expr = self.getValue(ctx.expr(0))
symbol = self.symbol_table[ctx.expr(0).getText().lower()]
if ctx.expr(0) in self.matrix_expr or (expr in self.type.keys() and self.type[expr] == "matrix"):
self.write(symbol + " = " + "_sm.Matrix([_sm.factor(i," + self.getValue(ctx.expr(1)) +
") for i in " + expr + "])" +
".reshape((" + expr + ").shape[0], " + "(" + expr + ").shape[1])\n")
else:
self.write(expr + " = " + "_sm.factor(" + expr + ", " +
self.getValue(ctx.expr(1)) + ")\n")
# Solve(Zero, x, y)
elif func_name == "solve":
l = []
l2 = []
num = 0
for i in range(1, ctx.getChildCount()):
if ctx.getChild(i).getText() == ",":
num+=1
try:
l.append(self.getValue(ctx.getChild(i)))
except Exception:
l.append(ctx.getChild(i).getText())
if i != 2:
try:
l2.append(self.getValue(ctx.getChild(i)))
except Exception:
pass
for i in l2:
self.explicit.update({i: "_sm.solve" + "".join(l) + "[" + i + "]"})
self.write("print(_sm.solve" + "".join(l) + ")\n")
# Arrange(y, n, x) *
elif func_name == "arrange":
expr = self.getValue(ctx.expr(0))
symbol = self.symbol_table[ctx.expr(0).getText().lower()]
if ctx.expr(0) in self.matrix_expr or (expr in self.type.keys() and self.type[expr] == "matrix"):
self.write(symbol + " = " + "_sm.Matrix([i.collect(" + self.getValue(ctx.expr(2)) +
")" + "for i in " + expr + "])" +
".reshape((" + expr + ").shape[0], " + "(" + expr + ").shape[1])\n")
else:
self.write(self.getValue(ctx.expr(0)) + ".collect(" +
self.getValue(ctx.expr(2)) + ")\n")
# Eig(M, EigenValue, EigenVec)
elif func_name == "eig":
self.symbol_table.update({ctx.expr(1).getText().lower(): ctx.expr(1).getText().lower()})
self.symbol_table.update({ctx.expr(2).getText().lower(): ctx.expr(2).getText().lower()})
# _sm.Matrix([i.evalf() for i in (i_s_so).eigenvals().keys()])
self.write(ctx.expr(1).getText().lower() + " = " +
"_sm.Matrix([i.evalf() for i in " +
"(" + self.getValue(ctx.expr(0)) + ")" + ".eigenvals().keys()])\n")
# _sm.Matrix([i[2][0].evalf() for i in (i_s_o).eigenvects()]).reshape(i_s_o.shape[0], i_s_o.shape[1])
self.write(ctx.expr(2).getText().lower() + " = " +
"_sm.Matrix([i[2][0].evalf() for i in " + "(" + self.getValue(ctx.expr(0)) + ")" +
".eigenvects()]).reshape(" + self.getValue(ctx.expr(0)) + ".shape[0], " +
self.getValue(ctx.expr(0)) + ".shape[1])\n")
# Simprot(N, A, 3, qA)
elif func_name == "simprot":
# A.orient(N, 'Axis', qA, N.z)
if self.type2[ctx.expr(0).getText().lower()] == "frame":
frame1 = self.symbol_table2[ctx.expr(0).getText().lower()]
elif self.type2[ctx.expr(0).getText().lower()] == "bodies":
frame1 = self.symbol_table2[ctx.expr(0).getText().lower()] + "_f"
if self.type2[ctx.expr(1).getText().lower()] == "frame":
frame2 = self.symbol_table2[ctx.expr(1).getText().lower()]
elif self.type2[ctx.expr(1).getText().lower()] == "bodies":
frame2 = self.symbol_table2[ctx.expr(1).getText().lower()] + "_f"
e2 = ""
if ctx.expr(2).getText()[0] == "-":
e2 = "-1*"
if ctx.expr(2).getText() in ("1", "-1"):
e = frame1 + ".x"
elif ctx.expr(2).getText() in ("2", "-2"):
e = frame1 + ".y"
elif ctx.expr(2).getText() in ("3", "-3"):
e = frame1 + ".z"
else:
e = self.getValue(ctx.expr(2))
e2 = ""
if "degrees" in self.settings.keys() and self.settings["degrees"] == "off":
value = self.getValue(ctx.expr(3))
else:
if ctx.expr(3) in self.numeric_expr:
value = "_np.deg2rad(" + self.getValue(ctx.expr(3)) + ")"
else:
value = self.getValue(ctx.expr(3))
self.write(frame2 + ".orient(" + frame1 +
", " + "'Axis'" + ", " + "[" + value +
", " + e2 + e + "]" + ")\n")
# Express(A2>, B) *
elif func_name == "express":
if self.type2[ctx.expr(1).getText().lower()] == "bodies":
f = "_f"
else:
f = ""
if '_' in ctx.expr(0).getText().lower() and ctx.expr(0).getText().count('_') == 2:
vec = ctx.expr(0).getText().lower().replace(">", "").split('_')
v1 = self.symbol_table2[vec[1]]
v2 = self.symbol_table2[vec[2]]
if vec[0] == "p":
self.write(v2 + ".set_pos(" + v1 + ", " + "(" + self.getValue(ctx.expr(0)) +
")" + ".express(" + self.symbol_table2[ctx.expr(1).getText().lower()] + f + "))\n")
elif vec[0] == "v":
self.write(v1 + ".set_vel(" + v2 + ", " + "(" + self.getValue(ctx.expr(0)) +
")" + ".express(" + self.symbol_table2[ctx.expr(1).getText().lower()] + f + "))\n")
elif vec[0] == "a":
self.write(v1 + ".set_acc(" + v2 + ", " + "(" + self.getValue(ctx.expr(0)) +
")" + ".express(" + self.symbol_table2[ctx.expr(1).getText().lower()] + f + "))\n")
else:
self.write(self.getValue(ctx.expr(0)) + " = " + "(" + self.getValue(ctx.expr(0)) + ")" + ".express(" +
self.symbol_table2[ctx.expr(1).getText().lower()] + f + ")\n")
else:
self.write(self.getValue(ctx.expr(0)) + " = " + "(" + self.getValue(ctx.expr(0)) + ")" + ".express(" +
self.symbol_table2[ctx.expr(1).getText().lower()] + f + ")\n")
# Angvel(A, B)
elif func_name == "angvel":
self.write("print(" + self.symbol_table2[ctx.expr(1).getText().lower()] +
".ang_vel_in(" + self.symbol_table2[ctx.expr(0).getText().lower()] + "))\n")
# v2pts(N, A, O, P)
elif func_name in ("v2pts", "a2pts", "v2pt", "a1pt"):
if func_name == "v2pts":
text = ".v2pt_theory("
elif func_name == "a2pts":
text = ".a2pt_theory("
elif func_name == "v1pt":
text = ".v1pt_theory("
elif func_name == "a1pt":
text = ".a1pt_theory("
if self.type2[ctx.expr(1).getText().lower()] == "frame":
frame = self.symbol_table2[ctx.expr(1).getText().lower()]
elif self.type2[ctx.expr(1).getText().lower()] == "bodies":
frame = self.symbol_table2[ctx.expr(1).getText().lower()] + "_f"
expr_list = []
for i in range(2, 4):
if self.type2[ctx.expr(i).getText().lower()] == "point":
expr_list.append(self.symbol_table2[ctx.expr(i).getText().lower()])
elif self.type2[ctx.expr(i).getText().lower()] == "particle":
expr_list.append(self.symbol_table2[ctx.expr(i).getText().lower()] + ".point")
self.write(expr_list[1] + text + expr_list[0] +
"," + self.symbol_table2[ctx.expr(0).getText().lower()] + "," +
frame + ")\n")
# Gravity(g*N1>)
elif func_name == "gravity":
for i in self.bodies.keys():
if self.type2[i] == "bodies":
e = self.symbol_table2[i] + ".masscenter"
elif self.type2[i] == "particle":
e = self.symbol_table2[i] + ".point"
if e in self.forces.keys():
self.forces[e] = self.forces[e] + self.symbol_table2[i] +\
".mass*(" + self.getValue(ctx.expr(0)) + ")"
else:
self.forces.update({e: self.symbol_table2[i] +
".mass*(" + self.getValue(ctx.expr(0)) + ")"})
self.write("force_" + i + " = " + self.forces[e] + "\n")
# Explicit(EXPRESS(IMPLICIT>,C))
elif func_name == "explicit":
if ctx.expr(0) in self.vector_expr:
self.vector_expr.append(ctx)
expr = self.getValue(ctx.expr(0))
if self.explicit.keys():
explicit_list = []
for i in self.explicit.keys():
explicit_list.append(i + ":" + self.explicit[i])
if '_' in ctx.expr(0).getText().lower() and ctx.expr(0).getText().count('_') == 2:
vec = ctx.expr(0).getText().lower().replace(">", "").split('_')
v1 = self.symbol_table2[vec[1]]
v2 = self.symbol_table2[vec[2]]
if vec[0] == "p":
self.write(v2 + ".set_pos(" + v1 + ", " + "(" + expr +
")" + ".subs({" + ", ".join(explicit_list) + "}))\n")
elif vec[0] == "v":
self.write(v2 + ".set_vel(" + v1 + ", " + "(" + expr +
")" + ".subs({" + ", ".join(explicit_list) + "}))\n")
elif vec[0] == "a":
self.write(v2 + ".set_acc(" + v1 + ", " + "(" + expr +
")" + ".subs({" + ", ".join(explicit_list) + "}))\n")
else:
self.write(expr + " = " + "(" + expr + ")" + ".subs({" + ", ".join(explicit_list) + "})\n")
else:
self.write(expr + " = " + "(" + expr + ")" + ".subs({" + ", ".join(explicit_list) + "})\n")
# Force(O/Q, -k*Stretch*Uvec>)
elif func_name in ("force", "torque"):
if "/" in ctx.expr(0).getText().lower():
p1 = ctx.expr(0).getText().lower().split('/')[0]
p2 = ctx.expr(0).getText().lower().split('/')[1]
if self.type2[p1] in ("point", "frame"):
pt1 = self.symbol_table2[p1]
elif self.type2[p1] == "particle":
pt1 = self.symbol_table2[p1] + ".point"
if self.type2[p2] in ("point", "frame"):
pt2 = self.symbol_table2[p2]
elif self.type2[p2] == "particle":
pt2 = self.symbol_table2[p2] + ".point"
if pt1 in self.forces.keys():
self.forces[pt1] = self.forces[pt1] + " + -1*("+self.getValue(ctx.expr(1)) + ")"
self.write("force_" + p1 + " = " + self.forces[pt1] + "\n")
else:
self.forces.update({pt1: "-1*("+self.getValue(ctx.expr(1)) + ")"})
self.write("force_" + p1 + " = " + self.forces[pt1] + "\n")
if pt2 in self.forces.keys():
self.forces[pt2] = self.forces[pt2] + "+ " + self.getValue(ctx.expr(1))
self.write("force_" + p2 + " = " + self.forces[pt2] + "\n")
else:
self.forces.update({pt2: self.getValue(ctx.expr(1))})
self.write("force_" + p2 + " = " + self.forces[pt2] + "\n")
elif ctx.expr(0).getChildCount() == 1:
p1 = ctx.expr(0).getText().lower()
if self.type2[p1] in ("point", "frame"):
pt1 = self.symbol_table2[p1]
elif self.type2[p1] == "particle":
pt1 = self.symbol_table2[p1] + ".point"
if pt1 in self.forces.keys():
self.forces[pt1] = self.forces[pt1] + "+ -1*(" + self.getValue(ctx.expr(1)) + ")"
else:
self.forces.update({pt1: "-1*(" + self.getValue(ctx.expr(1)) + ")"})
# Constrain(Dependent[qB])
elif func_name == "constrain":
if ctx.getChild(2).getChild(0).getText().lower() == "dependent":
self.write("velocity_constraints = [i for i in dependent]\n")
x = (ctx.expr(0).getChildCount()-2)//2
for i in range(x):
self.dependent_variables.append(self.getValue(ctx.expr(0).expr(i)))
# Kane()
elif func_name == "kane":
if ctx.getChildCount() == 3:
self.kane_type = "no_args"
# Settings
def exitSettings(self, ctx):
# Stores settings like Complex on/off, Degrees on/off etc in self.settings.
try:
self.settings.update({ctx.getChild(0).getText().lower():
ctx.getChild(1).getText().lower()})
except Exception:
pass
def exitMassDecl2(self, ctx):
# Used for declaring the masses of particles and rigidbodies.
particle = self.symbol_table2[ctx.getChild(0).getText().lower()]
if ctx.getText().count("=") == 2:
if ctx.expr().expr(1) in self.numeric_expr:
e = "_sm.S(" + self.getValue(ctx.expr().expr(1)) + ")"
else:
e = self.getValue(ctx.expr().expr(1))
self.symbol_table.update({ctx.expr().expr(0).getText().lower(): ctx.expr().expr(0).getText().lower()})
self.write(ctx.expr().expr(0).getText().lower() + " = " + e + "\n")
mass = ctx.expr().expr(0).getText().lower()
else:
try:
if ctx.expr() in self.numeric_expr:
mass = "_sm.S(" + self.getValue(ctx.expr()) + ")"
else:
mass = self.getValue(ctx.expr())
except Exception:
a_text = ctx.expr().getText().lower()
self.symbol_table.update({a_text: a_text})
self.type.update({a_text: "constants"})
self.write(a_text + " = " + "_sm.symbols('" + a_text + "')\n")
mass = a_text
self.write(particle + ".mass = " + mass + "\n")
def exitInertiaDecl(self, ctx):
inertia_list = []
try:
ctx.ID(1).getText()
num = 5
except Exception:
num = 2
for i in range((ctx.getChildCount()-num)//2):
try:
if ctx.expr(i) in self.numeric_expr:
inertia_list.append("_sm.S(" + self.getValue(ctx.expr(i)) + ")")
else:
inertia_list.append(self.getValue(ctx.expr(i)))
except Exception:
a_text = ctx.expr(i).getText().lower()
self.symbol_table.update({a_text: a_text})
self.type.update({a_text: "constants"})
self.write(a_text + " = " + "_sm.symbols('" + a_text + "')\n")
inertia_list.append(a_text)
if len(inertia_list) < 6:
for i in range(6-len(inertia_list)):
inertia_list.append("0")
# body_a.inertia = (_me.inertia(body_a, I1, I2, I3, 0, 0, 0), body_a_cm)
try:
frame = self.symbol_table2[ctx.ID(1).getText().lower()]
point = self.symbol_table2[ctx.ID(0).getText().lower().split('_')[1]]
body = self.symbol_table2[ctx.ID(0).getText().lower().split('_')[0]]
self.inertia_point.update({ctx.ID(0).getText().lower().split('_')[0]
: ctx.ID(0).getText().lower().split('_')[1]})
self.write(body + ".inertia" + " = " + "(_me.inertia(" + frame + ", " +
", ".join(inertia_list) + "), " + point + ")\n")
except Exception:
body_name = self.symbol_table2[ctx.ID(0).getText().lower()]
body_name_cm = body_name + "_cm"
self.inertia_point.update({ctx.ID(0).getText().lower(): ctx.ID(0).getText().lower() + "o"})
self.write(body_name + ".inertia" + " = " + "(_me.inertia(" + body_name + "_f" + ", " +
", ".join(inertia_list) + "), " + body_name_cm + ")\n")
PK ]ZZZ���� � - sympy/parsing/autolev/_parse_autolev_antlr.pyfrom importlib.metadata import version
from sympy.external import import_module
autolevparser = import_module('sympy.parsing.autolev._antlr.autolevparser',
import_kwargs={'fromlist': ['AutolevParser']})
autolevlexer = import_module('sympy.parsing.autolev._antlr.autolevlexer',
import_kwargs={'fromlist': ['AutolevLexer']})
autolevlistener = import_module('sympy.parsing.autolev._antlr.autolevlistener',
import_kwargs={'fromlist': ['AutolevListener']})
AutolevParser = getattr(autolevparser, 'AutolevParser', None)
AutolevLexer = getattr(autolevlexer, 'AutolevLexer', None)
AutolevListener = getattr(autolevlistener, 'AutolevListener', None)
def parse_autolev(autolev_code, include_numeric):
antlr4 = import_module('antlr4')
if not antlr4 or not version('antlr4-python3-runtime').startswith('4.11'):
raise ImportError("Autolev parsing requires the antlr4 Python package,"
" provided by pip (antlr4-python3-runtime)"
" conda (antlr-python-runtime), version 4.11")
try:
l = autolev_code.readlines()
input_stream = antlr4.InputStream("".join(l))
except Exception:
input_stream = antlr4.InputStream(autolev_code)
if AutolevListener:
from ._listener_autolev_antlr import MyListener
lexer = AutolevLexer(input_stream)
token_stream = antlr4.CommonTokenStream(lexer)
parser = AutolevParser(token_stream)
tree = parser.prog()
my_listener = MyListener(include_numeric)
walker = antlr4.ParseTreeWalker()
walker.walk(my_listener, tree)
return "".join(my_listener.output_code)
PK ]ZZZ���� � ( sympy/parsing/autolev/_antlr/__init__.py# *** GENERATED BY `setup.py antlr`, DO NOT EDIT BY HAND ***
#
# Generated with antlr4
# antlr4 is licensed under the BSD-3-Clause License
# https://github.com/antlr/antlr4/blob/master/LICENSE.txt
PK ]ZZZ��l�)5 )5 , sympy/parsing/autolev/_antlr/autolevlexer.py# *** GENERATED BY `setup.py antlr`, DO NOT EDIT BY HAND ***
#
# Generated with antlr4
# antlr4 is licensed under the BSD-3-Clause License
# https://github.com/antlr/antlr4/blob/master/LICENSE.txt
from antlr4 import *
from io import StringIO
import sys
if sys.version_info[1] > 5:
from typing import TextIO
else:
from typing.io import TextIO
def serializedATN():
return [
4,0,49,393,6,-1,2,0,7,0,2,1,7,1,2,2,7,2,2,3,7,3,2,4,7,4,2,5,7,5,
2,6,7,6,2,7,7,7,2,8,7,8,2,9,7,9,2,10,7,10,2,11,7,11,2,12,7,12,2,
13,7,13,2,14,7,14,2,15,7,15,2,16,7,16,2,17,7,17,2,18,7,18,2,19,7,
19,2,20,7,20,2,21,7,21,2,22,7,22,2,23,7,23,2,24,7,24,2,25,7,25,2,
26,7,26,2,27,7,27,2,28,7,28,2,29,7,29,2,30,7,30,2,31,7,31,2,32,7,
32,2,33,7,33,2,34,7,34,2,35,7,35,2,36,7,36,2,37,7,37,2,38,7,38,2,
39,7,39,2,40,7,40,2,41,7,41,2,42,7,42,2,43,7,43,2,44,7,44,2,45,7,
45,2,46,7,46,2,47,7,47,2,48,7,48,2,49,7,49,2,50,7,50,1,0,1,0,1,1,
1,1,1,2,1,2,1,3,1,3,1,3,1,4,1,4,1,4,1,5,1,5,1,5,1,6,1,6,1,6,1,7,
1,7,1,7,1,8,1,8,1,8,1,9,1,9,1,10,1,10,1,11,1,11,1,12,1,12,1,13,1,
13,1,14,1,14,1,15,1,15,1,16,1,16,1,17,1,17,1,18,1,18,1,19,1,19,1,
20,1,20,1,21,1,21,1,21,1,22,1,22,1,22,1,22,1,23,1,23,1,24,1,24,1,
25,1,25,1,26,1,26,1,26,1,26,1,26,1,27,1,27,1,27,1,27,1,27,1,27,1,
27,1,27,1,28,1,28,1,28,1,28,1,28,1,28,3,28,184,8,28,1,29,1,29,1,
29,1,29,1,29,1,29,1,29,1,30,1,30,1,30,1,30,1,30,1,31,1,31,1,31,1,
31,1,31,1,31,1,31,1,31,1,31,1,31,1,31,1,32,1,32,1,32,1,32,1,32,1,
32,1,32,1,33,1,33,1,33,1,33,1,33,1,33,1,33,1,33,1,33,1,33,1,34,1,
34,1,34,1,34,1,34,1,34,3,34,232,8,34,1,35,1,35,1,35,1,35,1,35,1,
35,3,35,240,8,35,1,36,1,36,1,36,1,36,1,36,1,36,1,36,1,36,1,36,3,
36,251,8,36,1,37,1,37,1,37,1,37,1,37,1,37,3,37,259,8,37,1,38,1,38,
1,38,1,38,1,38,1,38,1,38,1,38,1,38,3,38,270,8,38,1,39,1,39,1,39,
1,39,1,39,1,39,1,39,1,39,1,39,1,39,3,39,282,8,39,1,40,1,40,1,40,
1,40,1,40,1,40,1,40,1,40,1,40,1,40,1,41,1,41,1,41,1,41,1,41,1,41,
1,41,1,41,1,41,3,41,303,8,41,1,42,1,42,1,42,1,42,1,42,1,42,1,42,
1,42,1,42,1,42,1,42,1,42,1,42,1,42,1,42,3,42,320,8,42,1,43,5,43,
323,8,43,10,43,12,43,326,9,43,1,44,1,44,1,45,4,45,331,8,45,11,45,
12,45,332,1,46,4,46,336,8,46,11,46,12,46,337,1,46,1,46,5,46,342,
8,46,10,46,12,46,345,9,46,1,46,1,46,4,46,349,8,46,11,46,12,46,350,
3,46,353,8,46,1,47,1,47,1,47,1,47,1,47,1,47,1,47,1,47,1,47,3,47,
364,8,47,1,48,1,48,5,48,368,8,48,10,48,12,48,371,9,48,1,48,3,48,
374,8,48,1,48,1,48,1,48,1,48,1,49,1,49,5,49,382,8,49,10,49,12,49,
385,9,49,1,50,4,50,388,8,50,11,50,12,50,389,1,50,1,50,1,369,0,51,
1,1,3,2,5,3,7,4,9,5,11,6,13,7,15,8,17,9,19,10,21,11,23,12,25,13,
27,14,29,15,31,16,33,17,35,18,37,19,39,20,41,21,43,22,45,23,47,24,
49,25,51,26,53,27,55,28,57,29,59,30,61,31,63,32,65,33,67,34,69,35,
71,36,73,37,75,38,77,39,79,40,81,41,83,42,85,43,87,0,89,0,91,44,
93,45,95,46,97,47,99,48,101,49,1,0,24,2,0,77,77,109,109,2,0,65,65,
97,97,2,0,83,83,115,115,2,0,73,73,105,105,2,0,78,78,110,110,2,0,
69,69,101,101,2,0,82,82,114,114,2,0,84,84,116,116,2,0,80,80,112,
112,2,0,85,85,117,117,2,0,79,79,111,111,2,0,86,86,118,118,2,0,89,
89,121,121,2,0,67,67,99,99,2,0,68,68,100,100,2,0,87,87,119,119,2,
0,70,70,102,102,2,0,66,66,98,98,2,0,76,76,108,108,2,0,71,71,103,
103,1,0,48,57,2,0,65,90,97,122,4,0,48,57,65,90,95,95,97,122,4,0,
9,10,13,13,32,32,38,38,410,0,1,1,0,0,0,0,3,1,0,0,0,0,5,1,0,0,0,0,
7,1,0,0,0,0,9,1,0,0,0,0,11,1,0,0,0,0,13,1,0,0,0,0,15,1,0,0,0,0,17,
1,0,0,0,0,19,1,0,0,0,0,21,1,0,0,0,0,23,1,0,0,0,0,25,1,0,0,0,0,27,
1,0,0,0,0,29,1,0,0,0,0,31,1,0,0,0,0,33,1,0,0,0,0,35,1,0,0,0,0,37,
1,0,0,0,0,39,1,0,0,0,0,41,1,0,0,0,0,43,1,0,0,0,0,45,1,0,0,0,0,47,
1,0,0,0,0,49,1,0,0,0,0,51,1,0,0,0,0,53,1,0,0,0,0,55,1,0,0,0,0,57,
1,0,0,0,0,59,1,0,0,0,0,61,1,0,0,0,0,63,1,0,0,0,0,65,1,0,0,0,0,67,
1,0,0,0,0,69,1,0,0,0,0,71,1,0,0,0,0,73,1,0,0,0,0,75,1,0,0,0,0,77,
1,0,0,0,0,79,1,0,0,0,0,81,1,0,0,0,0,83,1,0,0,0,0,85,1,0,0,0,0,91,
1,0,0,0,0,93,1,0,0,0,0,95,1,0,0,0,0,97,1,0,0,0,0,99,1,0,0,0,0,101,
1,0,0,0,1,103,1,0,0,0,3,105,1,0,0,0,5,107,1,0,0,0,7,109,1,0,0,0,
9,112,1,0,0,0,11,115,1,0,0,0,13,118,1,0,0,0,15,121,1,0,0,0,17,124,
1,0,0,0,19,127,1,0,0,0,21,129,1,0,0,0,23,131,1,0,0,0,25,133,1,0,
0,0,27,135,1,0,0,0,29,137,1,0,0,0,31,139,1,0,0,0,33,141,1,0,0,0,
35,143,1,0,0,0,37,145,1,0,0,0,39,147,1,0,0,0,41,149,1,0,0,0,43,151,
1,0,0,0,45,154,1,0,0,0,47,158,1,0,0,0,49,160,1,0,0,0,51,162,1,0,
0,0,53,164,1,0,0,0,55,169,1,0,0,0,57,177,1,0,0,0,59,185,1,0,0,0,
61,192,1,0,0,0,63,197,1,0,0,0,65,208,1,0,0,0,67,215,1,0,0,0,69,225,
1,0,0,0,71,233,1,0,0,0,73,241,1,0,0,0,75,252,1,0,0,0,77,260,1,0,
0,0,79,271,1,0,0,0,81,283,1,0,0,0,83,293,1,0,0,0,85,304,1,0,0,0,
87,324,1,0,0,0,89,327,1,0,0,0,91,330,1,0,0,0,93,352,1,0,0,0,95,363,
1,0,0,0,97,365,1,0,0,0,99,379,1,0,0,0,101,387,1,0,0,0,103,104,5,
91,0,0,104,2,1,0,0,0,105,106,5,93,0,0,106,4,1,0,0,0,107,108,5,61,
0,0,108,6,1,0,0,0,109,110,5,43,0,0,110,111,5,61,0,0,111,8,1,0,0,
0,112,113,5,45,0,0,113,114,5,61,0,0,114,10,1,0,0,0,115,116,5,58,
0,0,116,117,5,61,0,0,117,12,1,0,0,0,118,119,5,42,0,0,119,120,5,61,
0,0,120,14,1,0,0,0,121,122,5,47,0,0,122,123,5,61,0,0,123,16,1,0,
0,0,124,125,5,94,0,0,125,126,5,61,0,0,126,18,1,0,0,0,127,128,5,44,
0,0,128,20,1,0,0,0,129,130,5,39,0,0,130,22,1,0,0,0,131,132,5,40,
0,0,132,24,1,0,0,0,133,134,5,41,0,0,134,26,1,0,0,0,135,136,5,123,
0,0,136,28,1,0,0,0,137,138,5,125,0,0,138,30,1,0,0,0,139,140,5,58,
0,0,140,32,1,0,0,0,141,142,5,43,0,0,142,34,1,0,0,0,143,144,5,45,
0,0,144,36,1,0,0,0,145,146,5,59,0,0,146,38,1,0,0,0,147,148,5,46,
0,0,148,40,1,0,0,0,149,150,5,62,0,0,150,42,1,0,0,0,151,152,5,48,
0,0,152,153,5,62,0,0,153,44,1,0,0,0,154,155,5,49,0,0,155,156,5,62,
0,0,156,157,5,62,0,0,157,46,1,0,0,0,158,159,5,94,0,0,159,48,1,0,
0,0,160,161,5,42,0,0,161,50,1,0,0,0,162,163,5,47,0,0,163,52,1,0,
0,0,164,165,7,0,0,0,165,166,7,1,0,0,166,167,7,2,0,0,167,168,7,2,
0,0,168,54,1,0,0,0,169,170,7,3,0,0,170,171,7,4,0,0,171,172,7,5,0,
0,172,173,7,6,0,0,173,174,7,7,0,0,174,175,7,3,0,0,175,176,7,1,0,
0,176,56,1,0,0,0,177,178,7,3,0,0,178,179,7,4,0,0,179,180,7,8,0,0,
180,181,7,9,0,0,181,183,7,7,0,0,182,184,7,2,0,0,183,182,1,0,0,0,
183,184,1,0,0,0,184,58,1,0,0,0,185,186,7,10,0,0,186,187,7,9,0,0,
187,188,7,7,0,0,188,189,7,8,0,0,189,190,7,9,0,0,190,191,7,7,0,0,
191,60,1,0,0,0,192,193,7,2,0,0,193,194,7,1,0,0,194,195,7,11,0,0,
195,196,7,5,0,0,196,62,1,0,0,0,197,198,7,9,0,0,198,199,7,4,0,0,199,
200,7,3,0,0,200,201,7,7,0,0,201,202,7,2,0,0,202,203,7,12,0,0,203,
204,7,2,0,0,204,205,7,7,0,0,205,206,7,5,0,0,206,207,7,0,0,0,207,
64,1,0,0,0,208,209,7,5,0,0,209,210,7,4,0,0,210,211,7,13,0,0,211,
212,7,10,0,0,212,213,7,14,0,0,213,214,7,5,0,0,214,66,1,0,0,0,215,
216,7,4,0,0,216,217,7,5,0,0,217,218,7,15,0,0,218,219,7,7,0,0,219,
220,7,10,0,0,220,221,7,4,0,0,221,222,7,3,0,0,222,223,7,1,0,0,223,
224,7,4,0,0,224,68,1,0,0,0,225,226,7,16,0,0,226,227,7,6,0,0,227,
228,7,1,0,0,228,229,7,0,0,0,229,231,7,5,0,0,230,232,7,2,0,0,231,
230,1,0,0,0,231,232,1,0,0,0,232,70,1,0,0,0,233,234,7,17,0,0,234,
235,7,10,0,0,235,236,7,14,0,0,236,237,7,3,0,0,237,239,7,5,0,0,238,
240,7,2,0,0,239,238,1,0,0,0,239,240,1,0,0,0,240,72,1,0,0,0,241,242,
7,8,0,0,242,243,7,1,0,0,243,244,7,6,0,0,244,245,7,7,0,0,245,246,
7,3,0,0,246,247,7,13,0,0,247,248,7,18,0,0,248,250,7,5,0,0,249,251,
7,2,0,0,250,249,1,0,0,0,250,251,1,0,0,0,251,74,1,0,0,0,252,253,7,
8,0,0,253,254,7,10,0,0,254,255,7,3,0,0,255,256,7,4,0,0,256,258,7,
7,0,0,257,259,7,2,0,0,258,257,1,0,0,0,258,259,1,0,0,0,259,76,1,0,
0,0,260,261,7,13,0,0,261,262,7,10,0,0,262,263,7,4,0,0,263,264,7,
2,0,0,264,265,7,7,0,0,265,266,7,1,0,0,266,267,7,4,0,0,267,269,7,
7,0,0,268,270,7,2,0,0,269,268,1,0,0,0,269,270,1,0,0,0,270,78,1,0,
0,0,271,272,7,2,0,0,272,273,7,8,0,0,273,274,7,5,0,0,274,275,7,13,
0,0,275,276,7,3,0,0,276,277,7,16,0,0,277,278,7,3,0,0,278,279,7,5,
0,0,279,281,7,14,0,0,280,282,7,2,0,0,281,280,1,0,0,0,281,282,1,0,
0,0,282,80,1,0,0,0,283,284,7,3,0,0,284,285,7,0,0,0,285,286,7,1,0,
0,286,287,7,19,0,0,287,288,7,3,0,0,288,289,7,4,0,0,289,290,7,1,0,
0,290,291,7,6,0,0,291,292,7,12,0,0,292,82,1,0,0,0,293,294,7,11,0,
0,294,295,7,1,0,0,295,296,7,6,0,0,296,297,7,3,0,0,297,298,7,1,0,
0,298,299,7,17,0,0,299,300,7,18,0,0,300,302,7,5,0,0,301,303,7,2,
0,0,302,301,1,0,0,0,302,303,1,0,0,0,303,84,1,0,0,0,304,305,7,0,0,
0,305,306,7,10,0,0,306,307,7,7,0,0,307,308,7,3,0,0,308,309,7,10,
0,0,309,310,7,4,0,0,310,311,7,11,0,0,311,312,7,1,0,0,312,313,7,6,
0,0,313,314,7,3,0,0,314,315,7,1,0,0,315,316,7,17,0,0,316,317,7,18,
0,0,317,319,7,5,0,0,318,320,7,2,0,0,319,318,1,0,0,0,319,320,1,0,
0,0,320,86,1,0,0,0,321,323,5,39,0,0,322,321,1,0,0,0,323,326,1,0,
0,0,324,322,1,0,0,0,324,325,1,0,0,0,325,88,1,0,0,0,326,324,1,0,0,
0,327,328,7,20,0,0,328,90,1,0,0,0,329,331,7,20,0,0,330,329,1,0,0,
0,331,332,1,0,0,0,332,330,1,0,0,0,332,333,1,0,0,0,333,92,1,0,0,0,
334,336,3,89,44,0,335,334,1,0,0,0,336,337,1,0,0,0,337,335,1,0,0,
0,337,338,1,0,0,0,338,339,1,0,0,0,339,343,5,46,0,0,340,342,3,89,
44,0,341,340,1,0,0,0,342,345,1,0,0,0,343,341,1,0,0,0,343,344,1,0,
0,0,344,353,1,0,0,0,345,343,1,0,0,0,346,348,5,46,0,0,347,349,3,89,
44,0,348,347,1,0,0,0,349,350,1,0,0,0,350,348,1,0,0,0,350,351,1,0,
0,0,351,353,1,0,0,0,352,335,1,0,0,0,352,346,1,0,0,0,353,94,1,0,0,
0,354,355,3,93,46,0,355,356,5,69,0,0,356,357,3,91,45,0,357,364,1,
0,0,0,358,359,3,93,46,0,359,360,5,69,0,0,360,361,5,45,0,0,361,362,
3,91,45,0,362,364,1,0,0,0,363,354,1,0,0,0,363,358,1,0,0,0,364,96,
1,0,0,0,365,369,5,37,0,0,366,368,9,0,0,0,367,366,1,0,0,0,368,371,
1,0,0,0,369,370,1,0,0,0,369,367,1,0,0,0,370,373,1,0,0,0,371,369,
1,0,0,0,372,374,5,13,0,0,373,372,1,0,0,0,373,374,1,0,0,0,374,375,
1,0,0,0,375,376,5,10,0,0,376,377,1,0,0,0,377,378,6,48,0,0,378,98,
1,0,0,0,379,383,7,21,0,0,380,382,7,22,0,0,381,380,1,0,0,0,382,385,
1,0,0,0,383,381,1,0,0,0,383,384,1,0,0,0,384,100,1,0,0,0,385,383,
1,0,0,0,386,388,7,23,0,0,387,386,1,0,0,0,388,389,1,0,0,0,389,387,
1,0,0,0,389,390,1,0,0,0,390,391,1,0,0,0,391,392,6,50,0,0,392,102,
1,0,0,0,21,0,183,231,239,250,258,269,281,302,319,324,332,337,343,
350,352,363,369,373,383,389,1,6,0,0
]
class AutolevLexer(Lexer):
atn = ATNDeserializer().deserialize(serializedATN())
decisionsToDFA = [ DFA(ds, i) for i, ds in enumerate(atn.decisionToState) ]
T__0 = 1
T__1 = 2
T__2 = 3
T__3 = 4
T__4 = 5
T__5 = 6
T__6 = 7
T__7 = 8
T__8 = 9
T__9 = 10
T__10 = 11
T__11 = 12
T__12 = 13
T__13 = 14
T__14 = 15
T__15 = 16
T__16 = 17
T__17 = 18
T__18 = 19
T__19 = 20
T__20 = 21
T__21 = 22
T__22 = 23
T__23 = 24
T__24 = 25
T__25 = 26
Mass = 27
Inertia = 28
Input = 29
Output = 30
Save = 31
UnitSystem = 32
Encode = 33
Newtonian = 34
Frames = 35
Bodies = 36
Particles = 37
Points = 38
Constants = 39
Specifieds = 40
Imaginary = 41
Variables = 42
MotionVariables = 43
INT = 44
FLOAT = 45
EXP = 46
LINE_COMMENT = 47
ID = 48
WS = 49
channelNames = [ u"DEFAULT_TOKEN_CHANNEL", u"HIDDEN" ]
modeNames = [ "DEFAULT_MODE" ]
literalNames = [ "<INVALID>",
"'['", "']'", "'='", "'+='", "'-='", "':='", "'*='", "'/='",
"'^='", "','", "'''", "'('", "')'", "'{'", "'}'", "':'", "'+'",
"'-'", "';'", "'.'", "'>'", "'0>'", "'1>>'", "'^'", "'*'", "'/'" ]
symbolicNames = [ "<INVALID>",
"Mass", "Inertia", "Input", "Output", "Save", "UnitSystem",
"Encode", "Newtonian", "Frames", "Bodies", "Particles", "Points",
"Constants", "Specifieds", "Imaginary", "Variables", "MotionVariables",
"INT", "FLOAT", "EXP", "LINE_COMMENT", "ID", "WS" ]
ruleNames = [ "T__0", "T__1", "T__2", "T__3", "T__4", "T__5", "T__6",
"T__7", "T__8", "T__9", "T__10", "T__11", "T__12", "T__13",
"T__14", "T__15", "T__16", "T__17", "T__18", "T__19",
"T__20", "T__21", "T__22", "T__23", "T__24", "T__25",
"Mass", "Inertia", "Input", "Output", "Save", "UnitSystem",
"Encode", "Newtonian", "Frames", "Bodies", "Particles",
"Points", "Constants", "Specifieds", "Imaginary", "Variables",
"MotionVariables", "DIFF", "DIGIT", "INT", "FLOAT", "EXP",
"LINE_COMMENT", "ID", "WS" ]
grammarFileName = "Autolev.g4"
def __init__(self, input=None, output:TextIO = sys.stdout):
super().__init__(input, output)
self.checkVersion("4.11.1")
self._interp = LexerATNSimulator(self, self.atn, self.decisionsToDFA, PredictionContextCache())
self._actions = None
self._predicates = None
PK ]ZZZ�w^ 2 2 / sympy/parsing/autolev/_antlr/autolevlistener.py# *** GENERATED BY `setup.py antlr`, DO NOT EDIT BY HAND ***
#
# Generated with antlr4
# antlr4 is licensed under the BSD-3-Clause License
# https://github.com/antlr/antlr4/blob/master/LICENSE.txt
from antlr4 import *
if __name__ is not None and "." in __name__:
from .autolevparser import AutolevParser
else:
from autolevparser import AutolevParser
# This class defines a complete listener for a parse tree produced by AutolevParser.
class AutolevListener(ParseTreeListener):
# Enter a parse tree produced by AutolevParser#prog.
def enterProg(self, ctx:AutolevParser.ProgContext):
pass
# Exit a parse tree produced by AutolevParser#prog.
def exitProg(self, ctx:AutolevParser.ProgContext):
pass
# Enter a parse tree produced by AutolevParser#stat.
def enterStat(self, ctx:AutolevParser.StatContext):
pass
# Exit a parse tree produced by AutolevParser#stat.
def exitStat(self, ctx:AutolevParser.StatContext):
pass
# Enter a parse tree produced by AutolevParser#vecAssign.
def enterVecAssign(self, ctx:AutolevParser.VecAssignContext):
pass
# Exit a parse tree produced by AutolevParser#vecAssign.
def exitVecAssign(self, ctx:AutolevParser.VecAssignContext):
pass
# Enter a parse tree produced by AutolevParser#indexAssign.
def enterIndexAssign(self, ctx:AutolevParser.IndexAssignContext):
pass
# Exit a parse tree produced by AutolevParser#indexAssign.
def exitIndexAssign(self, ctx:AutolevParser.IndexAssignContext):
pass
# Enter a parse tree produced by AutolevParser#regularAssign.
def enterRegularAssign(self, ctx:AutolevParser.RegularAssignContext):
pass
# Exit a parse tree produced by AutolevParser#regularAssign.
def exitRegularAssign(self, ctx:AutolevParser.RegularAssignContext):
pass
# Enter a parse tree produced by AutolevParser#equals.
def enterEquals(self, ctx:AutolevParser.EqualsContext):
pass
# Exit a parse tree produced by AutolevParser#equals.
def exitEquals(self, ctx:AutolevParser.EqualsContext):
pass
# Enter a parse tree produced by AutolevParser#index.
def enterIndex(self, ctx:AutolevParser.IndexContext):
pass
# Exit a parse tree produced by AutolevParser#index.
def exitIndex(self, ctx:AutolevParser.IndexContext):
pass
# Enter a parse tree produced by AutolevParser#diff.
def enterDiff(self, ctx:AutolevParser.DiffContext):
pass
# Exit a parse tree produced by AutolevParser#diff.
def exitDiff(self, ctx:AutolevParser.DiffContext):
pass
# Enter a parse tree produced by AutolevParser#functionCall.
def enterFunctionCall(self, ctx:AutolevParser.FunctionCallContext):
pass
# Exit a parse tree produced by AutolevParser#functionCall.
def exitFunctionCall(self, ctx:AutolevParser.FunctionCallContext):
pass
# Enter a parse tree produced by AutolevParser#varDecl.
def enterVarDecl(self, ctx:AutolevParser.VarDeclContext):
pass
# Exit a parse tree produced by AutolevParser#varDecl.
def exitVarDecl(self, ctx:AutolevParser.VarDeclContext):
pass
# Enter a parse tree produced by AutolevParser#varType.
def enterVarType(self, ctx:AutolevParser.VarTypeContext):
pass
# Exit a parse tree produced by AutolevParser#varType.
def exitVarType(self, ctx:AutolevParser.VarTypeContext):
pass
# Enter a parse tree produced by AutolevParser#varDecl2.
def enterVarDecl2(self, ctx:AutolevParser.VarDecl2Context):
pass
# Exit a parse tree produced by AutolevParser#varDecl2.
def exitVarDecl2(self, ctx:AutolevParser.VarDecl2Context):
pass
# Enter a parse tree produced by AutolevParser#ranges.
def enterRanges(self, ctx:AutolevParser.RangesContext):
pass
# Exit a parse tree produced by AutolevParser#ranges.
def exitRanges(self, ctx:AutolevParser.RangesContext):
pass
# Enter a parse tree produced by AutolevParser#massDecl.
def enterMassDecl(self, ctx:AutolevParser.MassDeclContext):
pass
# Exit a parse tree produced by AutolevParser#massDecl.
def exitMassDecl(self, ctx:AutolevParser.MassDeclContext):
pass
# Enter a parse tree produced by AutolevParser#massDecl2.
def enterMassDecl2(self, ctx:AutolevParser.MassDecl2Context):
pass
# Exit a parse tree produced by AutolevParser#massDecl2.
def exitMassDecl2(self, ctx:AutolevParser.MassDecl2Context):
pass
# Enter a parse tree produced by AutolevParser#inertiaDecl.
def enterInertiaDecl(self, ctx:AutolevParser.InertiaDeclContext):
pass
# Exit a parse tree produced by AutolevParser#inertiaDecl.
def exitInertiaDecl(self, ctx:AutolevParser.InertiaDeclContext):
pass
# Enter a parse tree produced by AutolevParser#matrix.
def enterMatrix(self, ctx:AutolevParser.MatrixContext):
pass
# Exit a parse tree produced by AutolevParser#matrix.
def exitMatrix(self, ctx:AutolevParser.MatrixContext):
pass
# Enter a parse tree produced by AutolevParser#matrixInOutput.
def enterMatrixInOutput(self, ctx:AutolevParser.MatrixInOutputContext):
pass
# Exit a parse tree produced by AutolevParser#matrixInOutput.
def exitMatrixInOutput(self, ctx:AutolevParser.MatrixInOutputContext):
pass
# Enter a parse tree produced by AutolevParser#codeCommands.
def enterCodeCommands(self, ctx:AutolevParser.CodeCommandsContext):
pass
# Exit a parse tree produced by AutolevParser#codeCommands.
def exitCodeCommands(self, ctx:AutolevParser.CodeCommandsContext):
pass
# Enter a parse tree produced by AutolevParser#settings.
def enterSettings(self, ctx:AutolevParser.SettingsContext):
pass
# Exit a parse tree produced by AutolevParser#settings.
def exitSettings(self, ctx:AutolevParser.SettingsContext):
pass
# Enter a parse tree produced by AutolevParser#units.
def enterUnits(self, ctx:AutolevParser.UnitsContext):
pass
# Exit a parse tree produced by AutolevParser#units.
def exitUnits(self, ctx:AutolevParser.UnitsContext):
pass
# Enter a parse tree produced by AutolevParser#inputs.
def enterInputs(self, ctx:AutolevParser.InputsContext):
pass
# Exit a parse tree produced by AutolevParser#inputs.
def exitInputs(self, ctx:AutolevParser.InputsContext):
pass
# Enter a parse tree produced by AutolevParser#id_diff.
def enterId_diff(self, ctx:AutolevParser.Id_diffContext):
pass
# Exit a parse tree produced by AutolevParser#id_diff.
def exitId_diff(self, ctx:AutolevParser.Id_diffContext):
pass
# Enter a parse tree produced by AutolevParser#inputs2.
def enterInputs2(self, ctx:AutolevParser.Inputs2Context):
pass
# Exit a parse tree produced by AutolevParser#inputs2.
def exitInputs2(self, ctx:AutolevParser.Inputs2Context):
pass
# Enter a parse tree produced by AutolevParser#outputs.
def enterOutputs(self, ctx:AutolevParser.OutputsContext):
pass
# Exit a parse tree produced by AutolevParser#outputs.
def exitOutputs(self, ctx:AutolevParser.OutputsContext):
pass
# Enter a parse tree produced by AutolevParser#outputs2.
def enterOutputs2(self, ctx:AutolevParser.Outputs2Context):
pass
# Exit a parse tree produced by AutolevParser#outputs2.
def exitOutputs2(self, ctx:AutolevParser.Outputs2Context):
pass
# Enter a parse tree produced by AutolevParser#codegen.
def enterCodegen(self, ctx:AutolevParser.CodegenContext):
pass
# Exit a parse tree produced by AutolevParser#codegen.
def exitCodegen(self, ctx:AutolevParser.CodegenContext):
pass
# Enter a parse tree produced by AutolevParser#commands.
def enterCommands(self, ctx:AutolevParser.CommandsContext):
pass
# Exit a parse tree produced by AutolevParser#commands.
def exitCommands(self, ctx:AutolevParser.CommandsContext):
pass
# Enter a parse tree produced by AutolevParser#vec.
def enterVec(self, ctx:AutolevParser.VecContext):
pass
# Exit a parse tree produced by AutolevParser#vec.
def exitVec(self, ctx:AutolevParser.VecContext):
pass
# Enter a parse tree produced by AutolevParser#parens.
def enterParens(self, ctx:AutolevParser.ParensContext):
pass
# Exit a parse tree produced by AutolevParser#parens.
def exitParens(self, ctx:AutolevParser.ParensContext):
pass
# Enter a parse tree produced by AutolevParser#VectorOrDyadic.
def enterVectorOrDyadic(self, ctx:AutolevParser.VectorOrDyadicContext):
pass
# Exit a parse tree produced by AutolevParser#VectorOrDyadic.
def exitVectorOrDyadic(self, ctx:AutolevParser.VectorOrDyadicContext):
pass
# Enter a parse tree produced by AutolevParser#Exponent.
def enterExponent(self, ctx:AutolevParser.ExponentContext):
pass
# Exit a parse tree produced by AutolevParser#Exponent.
def exitExponent(self, ctx:AutolevParser.ExponentContext):
pass
# Enter a parse tree produced by AutolevParser#MulDiv.
def enterMulDiv(self, ctx:AutolevParser.MulDivContext):
pass
# Exit a parse tree produced by AutolevParser#MulDiv.
def exitMulDiv(self, ctx:AutolevParser.MulDivContext):
pass
# Enter a parse tree produced by AutolevParser#AddSub.
def enterAddSub(self, ctx:AutolevParser.AddSubContext):
pass
# Exit a parse tree produced by AutolevParser#AddSub.
def exitAddSub(self, ctx:AutolevParser.AddSubContext):
pass
# Enter a parse tree produced by AutolevParser#float.
def enterFloat(self, ctx:AutolevParser.FloatContext):
pass
# Exit a parse tree produced by AutolevParser#float.
def exitFloat(self, ctx:AutolevParser.FloatContext):
pass
# Enter a parse tree produced by AutolevParser#int.
def enterInt(self, ctx:AutolevParser.IntContext):
pass
# Exit a parse tree produced by AutolevParser#int.
def exitInt(self, ctx:AutolevParser.IntContext):
pass
# Enter a parse tree produced by AutolevParser#idEqualsExpr.
def enterIdEqualsExpr(self, ctx:AutolevParser.IdEqualsExprContext):
pass
# Exit a parse tree produced by AutolevParser#idEqualsExpr.
def exitIdEqualsExpr(self, ctx:AutolevParser.IdEqualsExprContext):
pass
# Enter a parse tree produced by AutolevParser#negativeOne.
def enterNegativeOne(self, ctx:AutolevParser.NegativeOneContext):
pass
# Exit a parse tree produced by AutolevParser#negativeOne.
def exitNegativeOne(self, ctx:AutolevParser.NegativeOneContext):
pass
# Enter a parse tree produced by AutolevParser#function.
def enterFunction(self, ctx:AutolevParser.FunctionContext):
pass
# Exit a parse tree produced by AutolevParser#function.
def exitFunction(self, ctx:AutolevParser.FunctionContext):
pass
# Enter a parse tree produced by AutolevParser#rangess.
def enterRangess(self, ctx:AutolevParser.RangessContext):
pass
# Exit a parse tree produced by AutolevParser#rangess.
def exitRangess(self, ctx:AutolevParser.RangessContext):
pass
# Enter a parse tree produced by AutolevParser#colon.
def enterColon(self, ctx:AutolevParser.ColonContext):
pass
# Exit a parse tree produced by AutolevParser#colon.
def exitColon(self, ctx:AutolevParser.ColonContext):
pass
# Enter a parse tree produced by AutolevParser#id.
def enterId(self, ctx:AutolevParser.IdContext):
pass
# Exit a parse tree produced by AutolevParser#id.
def exitId(self, ctx:AutolevParser.IdContext):
pass
# Enter a parse tree produced by AutolevParser#exp.
def enterExp(self, ctx:AutolevParser.ExpContext):
pass
# Exit a parse tree produced by AutolevParser#exp.
def exitExp(self, ctx:AutolevParser.ExpContext):
pass
# Enter a parse tree produced by AutolevParser#matrices.
def enterMatrices(self, ctx:AutolevParser.MatricesContext):
pass
# Exit a parse tree produced by AutolevParser#matrices.
def exitMatrices(self, ctx:AutolevParser.MatricesContext):
pass
# Enter a parse tree produced by AutolevParser#Indexing.
def enterIndexing(self, ctx:AutolevParser.IndexingContext):
pass
# Exit a parse tree produced by AutolevParser#Indexing.
def exitIndexing(self, ctx:AutolevParser.IndexingContext):
pass
del AutolevParser
PK ]ZZZ�-+3� 3� - sympy/parsing/autolev/_antlr/autolevparser.py# *** GENERATED BY `setup.py antlr`, DO NOT EDIT BY HAND ***
#
# Generated with antlr4
# antlr4 is licensed under the BSD-3-Clause License
# https://github.com/antlr/antlr4/blob/master/LICENSE.txt
from antlr4 import *
from io import StringIO
import sys
if sys.version_info[1] > 5:
from typing import TextIO
else:
from typing.io import TextIO
def serializedATN():
return [
4,1,49,431,2,0,7,0,2,1,7,1,2,2,7,2,2,3,7,3,2,4,7,4,2,5,7,5,2,6,7,
6,2,7,7,7,2,8,7,8,2,9,7,9,2,10,7,10,2,11,7,11,2,12,7,12,2,13,7,13,
2,14,7,14,2,15,7,15,2,16,7,16,2,17,7,17,2,18,7,18,2,19,7,19,2,20,
7,20,2,21,7,21,2,22,7,22,2,23,7,23,2,24,7,24,2,25,7,25,2,26,7,26,
2,27,7,27,1,0,4,0,58,8,0,11,0,12,0,59,1,1,1,1,1,1,1,1,1,1,1,1,1,
1,3,1,69,8,1,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,
3,2,84,8,2,1,2,1,2,1,2,3,2,89,8,2,1,3,1,3,1,4,1,4,1,4,5,4,96,8,4,
10,4,12,4,99,9,4,1,5,4,5,102,8,5,11,5,12,5,103,1,6,1,6,1,6,1,6,1,
6,5,6,111,8,6,10,6,12,6,114,9,6,3,6,116,8,6,1,6,1,6,1,6,1,6,1,6,
1,6,5,6,124,8,6,10,6,12,6,127,9,6,3,6,129,8,6,1,6,3,6,132,8,6,1,
7,1,7,1,7,1,7,5,7,138,8,7,10,7,12,7,141,9,7,1,8,1,8,1,8,1,8,1,8,
1,8,1,8,1,8,1,8,1,8,5,8,153,8,8,10,8,12,8,156,9,8,1,8,1,8,5,8,160,
8,8,10,8,12,8,163,9,8,3,8,165,8,8,1,9,1,9,1,9,1,9,1,9,1,9,3,9,173,
8,9,1,9,1,9,1,9,1,9,1,9,1,9,1,9,1,9,5,9,183,8,9,10,9,12,9,186,9,
9,1,9,3,9,189,8,9,1,9,1,9,1,9,3,9,194,8,9,1,9,3,9,197,8,9,1,9,5,
9,200,8,9,10,9,12,9,203,9,9,1,9,1,9,3,9,207,8,9,1,10,1,10,1,10,1,
10,1,10,1,10,1,10,1,10,5,10,217,8,10,10,10,12,10,220,9,10,1,10,1,
10,1,11,1,11,1,11,1,11,5,11,228,8,11,10,11,12,11,231,9,11,1,12,1,
12,1,12,1,12,1,13,1,13,1,13,1,13,1,13,3,13,242,8,13,1,13,1,13,4,
13,246,8,13,11,13,12,13,247,1,14,1,14,1,14,1,14,5,14,254,8,14,10,
14,12,14,257,9,14,1,14,1,14,1,15,1,15,1,15,1,15,3,15,265,8,15,1,
15,1,15,3,15,269,8,15,1,16,1,16,1,16,1,16,1,16,3,16,276,8,16,1,17,
1,17,3,17,280,8,17,1,18,1,18,1,18,1,18,5,18,286,8,18,10,18,12,18,
289,9,18,1,19,1,19,1,19,1,19,5,19,295,8,19,10,19,12,19,298,9,19,
1,20,1,20,3,20,302,8,20,1,21,1,21,1,21,1,21,3,21,308,8,21,1,22,1,
22,1,22,1,22,5,22,314,8,22,10,22,12,22,317,9,22,1,23,1,23,3,23,321,
8,23,1,24,1,24,1,24,1,24,1,24,1,24,5,24,329,8,24,10,24,12,24,332,
9,24,1,24,1,24,3,24,336,8,24,1,24,1,24,1,24,1,24,1,25,1,25,1,25,
1,25,1,25,1,25,1,25,1,25,5,25,350,8,25,10,25,12,25,353,9,25,3,25,
355,8,25,1,26,1,26,4,26,359,8,26,11,26,12,26,360,1,26,1,26,3,26,
365,8,26,1,27,1,27,1,27,1,27,1,27,1,27,1,27,1,27,5,27,375,8,27,10,
27,12,27,378,9,27,1,27,1,27,1,27,1,27,1,27,1,27,5,27,386,8,27,10,
27,12,27,389,9,27,1,27,1,27,1,27,1,27,1,27,1,27,1,27,1,27,1,27,3,
27,400,8,27,1,27,1,27,5,27,404,8,27,10,27,12,27,407,9,27,3,27,409,
8,27,1,27,1,27,1,27,1,27,1,27,1,27,1,27,1,27,1,27,1,27,1,27,1,27,
1,27,1,27,1,27,5,27,426,8,27,10,27,12,27,429,9,27,1,27,0,1,54,28,
0,2,4,6,8,10,12,14,16,18,20,22,24,26,28,30,32,34,36,38,40,42,44,
46,48,50,52,54,0,7,1,0,3,9,1,0,27,28,1,0,17,18,2,0,10,10,19,19,1,
0,44,45,2,0,44,46,48,48,1,0,25,26,483,0,57,1,0,0,0,2,68,1,0,0,0,
4,88,1,0,0,0,6,90,1,0,0,0,8,92,1,0,0,0,10,101,1,0,0,0,12,131,1,0,
0,0,14,133,1,0,0,0,16,164,1,0,0,0,18,166,1,0,0,0,20,208,1,0,0,0,
22,223,1,0,0,0,24,232,1,0,0,0,26,236,1,0,0,0,28,249,1,0,0,0,30,268,
1,0,0,0,32,275,1,0,0,0,34,277,1,0,0,0,36,281,1,0,0,0,38,290,1,0,
0,0,40,299,1,0,0,0,42,303,1,0,0,0,44,309,1,0,0,0,46,318,1,0,0,0,
48,322,1,0,0,0,50,354,1,0,0,0,52,364,1,0,0,0,54,408,1,0,0,0,56,58,
3,2,1,0,57,56,1,0,0,0,58,59,1,0,0,0,59,57,1,0,0,0,59,60,1,0,0,0,
60,1,1,0,0,0,61,69,3,14,7,0,62,69,3,12,6,0,63,69,3,32,16,0,64,69,
3,22,11,0,65,69,3,26,13,0,66,69,3,4,2,0,67,69,3,34,17,0,68,61,1,
0,0,0,68,62,1,0,0,0,68,63,1,0,0,0,68,64,1,0,0,0,68,65,1,0,0,0,68,
66,1,0,0,0,68,67,1,0,0,0,69,3,1,0,0,0,70,71,3,52,26,0,71,72,3,6,
3,0,72,73,3,54,27,0,73,89,1,0,0,0,74,75,5,48,0,0,75,76,5,1,0,0,76,
77,3,8,4,0,77,78,5,2,0,0,78,79,3,6,3,0,79,80,3,54,27,0,80,89,1,0,
0,0,81,83,5,48,0,0,82,84,3,10,5,0,83,82,1,0,0,0,83,84,1,0,0,0,84,
85,1,0,0,0,85,86,3,6,3,0,86,87,3,54,27,0,87,89,1,0,0,0,88,70,1,0,
0,0,88,74,1,0,0,0,88,81,1,0,0,0,89,5,1,0,0,0,90,91,7,0,0,0,91,7,
1,0,0,0,92,97,3,54,27,0,93,94,5,10,0,0,94,96,3,54,27,0,95,93,1,0,
0,0,96,99,1,0,0,0,97,95,1,0,0,0,97,98,1,0,0,0,98,9,1,0,0,0,99,97,
1,0,0,0,100,102,5,11,0,0,101,100,1,0,0,0,102,103,1,0,0,0,103,101,
1,0,0,0,103,104,1,0,0,0,104,11,1,0,0,0,105,106,5,48,0,0,106,115,
5,12,0,0,107,112,3,54,27,0,108,109,5,10,0,0,109,111,3,54,27,0,110,
108,1,0,0,0,111,114,1,0,0,0,112,110,1,0,0,0,112,113,1,0,0,0,113,
116,1,0,0,0,114,112,1,0,0,0,115,107,1,0,0,0,115,116,1,0,0,0,116,
117,1,0,0,0,117,132,5,13,0,0,118,119,7,1,0,0,119,128,5,12,0,0,120,
125,5,48,0,0,121,122,5,10,0,0,122,124,5,48,0,0,123,121,1,0,0,0,124,
127,1,0,0,0,125,123,1,0,0,0,125,126,1,0,0,0,126,129,1,0,0,0,127,
125,1,0,0,0,128,120,1,0,0,0,128,129,1,0,0,0,129,130,1,0,0,0,130,
132,5,13,0,0,131,105,1,0,0,0,131,118,1,0,0,0,132,13,1,0,0,0,133,
134,3,16,8,0,134,139,3,18,9,0,135,136,5,10,0,0,136,138,3,18,9,0,
137,135,1,0,0,0,138,141,1,0,0,0,139,137,1,0,0,0,139,140,1,0,0,0,
140,15,1,0,0,0,141,139,1,0,0,0,142,165,5,34,0,0,143,165,5,35,0,0,
144,165,5,36,0,0,145,165,5,37,0,0,146,165,5,38,0,0,147,165,5,39,
0,0,148,165,5,40,0,0,149,165,5,41,0,0,150,154,5,42,0,0,151,153,5,
11,0,0,152,151,1,0,0,0,153,156,1,0,0,0,154,152,1,0,0,0,154,155,1,
0,0,0,155,165,1,0,0,0,156,154,1,0,0,0,157,161,5,43,0,0,158,160,5,
11,0,0,159,158,1,0,0,0,160,163,1,0,0,0,161,159,1,0,0,0,161,162,1,
0,0,0,162,165,1,0,0,0,163,161,1,0,0,0,164,142,1,0,0,0,164,143,1,
0,0,0,164,144,1,0,0,0,164,145,1,0,0,0,164,146,1,0,0,0,164,147,1,
0,0,0,164,148,1,0,0,0,164,149,1,0,0,0,164,150,1,0,0,0,164,157,1,
0,0,0,165,17,1,0,0,0,166,172,5,48,0,0,167,168,5,14,0,0,168,169,5,
44,0,0,169,170,5,10,0,0,170,171,5,44,0,0,171,173,5,15,0,0,172,167,
1,0,0,0,172,173,1,0,0,0,173,188,1,0,0,0,174,175,5,14,0,0,175,176,
5,44,0,0,176,177,5,16,0,0,177,184,5,44,0,0,178,179,5,10,0,0,179,
180,5,44,0,0,180,181,5,16,0,0,181,183,5,44,0,0,182,178,1,0,0,0,183,
186,1,0,0,0,184,182,1,0,0,0,184,185,1,0,0,0,185,187,1,0,0,0,186,
184,1,0,0,0,187,189,5,15,0,0,188,174,1,0,0,0,188,189,1,0,0,0,189,
193,1,0,0,0,190,191,5,14,0,0,191,192,5,44,0,0,192,194,5,15,0,0,193,
190,1,0,0,0,193,194,1,0,0,0,194,196,1,0,0,0,195,197,7,2,0,0,196,
195,1,0,0,0,196,197,1,0,0,0,197,201,1,0,0,0,198,200,5,11,0,0,199,
198,1,0,0,0,200,203,1,0,0,0,201,199,1,0,0,0,201,202,1,0,0,0,202,
206,1,0,0,0,203,201,1,0,0,0,204,205,5,3,0,0,205,207,3,54,27,0,206,
204,1,0,0,0,206,207,1,0,0,0,207,19,1,0,0,0,208,209,5,14,0,0,209,
210,5,44,0,0,210,211,5,16,0,0,211,218,5,44,0,0,212,213,5,10,0,0,
213,214,5,44,0,0,214,215,5,16,0,0,215,217,5,44,0,0,216,212,1,0,0,
0,217,220,1,0,0,0,218,216,1,0,0,0,218,219,1,0,0,0,219,221,1,0,0,
0,220,218,1,0,0,0,221,222,5,15,0,0,222,21,1,0,0,0,223,224,5,27,0,
0,224,229,3,24,12,0,225,226,5,10,0,0,226,228,3,24,12,0,227,225,1,
0,0,0,228,231,1,0,0,0,229,227,1,0,0,0,229,230,1,0,0,0,230,23,1,0,
0,0,231,229,1,0,0,0,232,233,5,48,0,0,233,234,5,3,0,0,234,235,3,54,
27,0,235,25,1,0,0,0,236,237,5,28,0,0,237,241,5,48,0,0,238,239,5,
12,0,0,239,240,5,48,0,0,240,242,5,13,0,0,241,238,1,0,0,0,241,242,
1,0,0,0,242,245,1,0,0,0,243,244,5,10,0,0,244,246,3,54,27,0,245,243,
1,0,0,0,246,247,1,0,0,0,247,245,1,0,0,0,247,248,1,0,0,0,248,27,1,
0,0,0,249,250,5,1,0,0,250,255,3,54,27,0,251,252,7,3,0,0,252,254,
3,54,27,0,253,251,1,0,0,0,254,257,1,0,0,0,255,253,1,0,0,0,255,256,
1,0,0,0,256,258,1,0,0,0,257,255,1,0,0,0,258,259,5,2,0,0,259,29,1,
0,0,0,260,261,5,48,0,0,261,262,5,48,0,0,262,264,5,3,0,0,263,265,
7,4,0,0,264,263,1,0,0,0,264,265,1,0,0,0,265,269,1,0,0,0,266,269,
5,45,0,0,267,269,5,44,0,0,268,260,1,0,0,0,268,266,1,0,0,0,268,267,
1,0,0,0,269,31,1,0,0,0,270,276,3,36,18,0,271,276,3,38,19,0,272,276,
3,44,22,0,273,276,3,48,24,0,274,276,3,50,25,0,275,270,1,0,0,0,275,
271,1,0,0,0,275,272,1,0,0,0,275,273,1,0,0,0,275,274,1,0,0,0,276,
33,1,0,0,0,277,279,5,48,0,0,278,280,7,5,0,0,279,278,1,0,0,0,279,
280,1,0,0,0,280,35,1,0,0,0,281,282,5,32,0,0,282,287,5,48,0,0,283,
284,5,10,0,0,284,286,5,48,0,0,285,283,1,0,0,0,286,289,1,0,0,0,287,
285,1,0,0,0,287,288,1,0,0,0,288,37,1,0,0,0,289,287,1,0,0,0,290,291,
5,29,0,0,291,296,3,42,21,0,292,293,5,10,0,0,293,295,3,42,21,0,294,
292,1,0,0,0,295,298,1,0,0,0,296,294,1,0,0,0,296,297,1,0,0,0,297,
39,1,0,0,0,298,296,1,0,0,0,299,301,5,48,0,0,300,302,3,10,5,0,301,
300,1,0,0,0,301,302,1,0,0,0,302,41,1,0,0,0,303,304,3,40,20,0,304,
305,5,3,0,0,305,307,3,54,27,0,306,308,3,54,27,0,307,306,1,0,0,0,
307,308,1,0,0,0,308,43,1,0,0,0,309,310,5,30,0,0,310,315,3,46,23,
0,311,312,5,10,0,0,312,314,3,46,23,0,313,311,1,0,0,0,314,317,1,0,
0,0,315,313,1,0,0,0,315,316,1,0,0,0,316,45,1,0,0,0,317,315,1,0,0,
0,318,320,3,54,27,0,319,321,3,54,27,0,320,319,1,0,0,0,320,321,1,
0,0,0,321,47,1,0,0,0,322,323,5,48,0,0,323,335,3,12,6,0,324,325,5,
1,0,0,325,330,3,30,15,0,326,327,5,10,0,0,327,329,3,30,15,0,328,326,
1,0,0,0,329,332,1,0,0,0,330,328,1,0,0,0,330,331,1,0,0,0,331,333,
1,0,0,0,332,330,1,0,0,0,333,334,5,2,0,0,334,336,1,0,0,0,335,324,
1,0,0,0,335,336,1,0,0,0,336,337,1,0,0,0,337,338,5,48,0,0,338,339,
5,20,0,0,339,340,5,48,0,0,340,49,1,0,0,0,341,342,5,31,0,0,342,343,
5,48,0,0,343,344,5,20,0,0,344,355,5,48,0,0,345,346,5,33,0,0,346,
351,5,48,0,0,347,348,5,10,0,0,348,350,5,48,0,0,349,347,1,0,0,0,350,
353,1,0,0,0,351,349,1,0,0,0,351,352,1,0,0,0,352,355,1,0,0,0,353,
351,1,0,0,0,354,341,1,0,0,0,354,345,1,0,0,0,355,51,1,0,0,0,356,358,
5,48,0,0,357,359,5,21,0,0,358,357,1,0,0,0,359,360,1,0,0,0,360,358,
1,0,0,0,360,361,1,0,0,0,361,365,1,0,0,0,362,365,5,22,0,0,363,365,
5,23,0,0,364,356,1,0,0,0,364,362,1,0,0,0,364,363,1,0,0,0,365,53,
1,0,0,0,366,367,6,27,-1,0,367,409,5,46,0,0,368,369,5,18,0,0,369,
409,3,54,27,12,370,409,5,45,0,0,371,409,5,44,0,0,372,376,5,48,0,
0,373,375,5,11,0,0,374,373,1,0,0,0,375,378,1,0,0,0,376,374,1,0,0,
0,376,377,1,0,0,0,377,409,1,0,0,0,378,376,1,0,0,0,379,409,3,52,26,
0,380,381,5,48,0,0,381,382,5,1,0,0,382,387,3,54,27,0,383,384,5,10,
0,0,384,386,3,54,27,0,385,383,1,0,0,0,386,389,1,0,0,0,387,385,1,
0,0,0,387,388,1,0,0,0,388,390,1,0,0,0,389,387,1,0,0,0,390,391,5,
2,0,0,391,409,1,0,0,0,392,409,3,12,6,0,393,409,3,28,14,0,394,395,
5,12,0,0,395,396,3,54,27,0,396,397,5,13,0,0,397,409,1,0,0,0,398,
400,5,48,0,0,399,398,1,0,0,0,399,400,1,0,0,0,400,401,1,0,0,0,401,
405,3,20,10,0,402,404,5,11,0,0,403,402,1,0,0,0,404,407,1,0,0,0,405,
403,1,0,0,0,405,406,1,0,0,0,406,409,1,0,0,0,407,405,1,0,0,0,408,
366,1,0,0,0,408,368,1,0,0,0,408,370,1,0,0,0,408,371,1,0,0,0,408,
372,1,0,0,0,408,379,1,0,0,0,408,380,1,0,0,0,408,392,1,0,0,0,408,
393,1,0,0,0,408,394,1,0,0,0,408,399,1,0,0,0,409,427,1,0,0,0,410,
411,10,16,0,0,411,412,5,24,0,0,412,426,3,54,27,17,413,414,10,15,
0,0,414,415,7,6,0,0,415,426,3,54,27,16,416,417,10,14,0,0,417,418,
7,2,0,0,418,426,3,54,27,15,419,420,10,3,0,0,420,421,5,3,0,0,421,
426,3,54,27,4,422,423,10,2,0,0,423,424,5,16,0,0,424,426,3,54,27,
3,425,410,1,0,0,0,425,413,1,0,0,0,425,416,1,0,0,0,425,419,1,0,0,
0,425,422,1,0,0,0,426,429,1,0,0,0,427,425,1,0,0,0,427,428,1,0,0,
0,428,55,1,0,0,0,429,427,1,0,0,0,50,59,68,83,88,97,103,112,115,125,
128,131,139,154,161,164,172,184,188,193,196,201,206,218,229,241,
247,255,264,268,275,279,287,296,301,307,315,320,330,335,351,354,
360,364,376,387,399,405,408,425,427
]
class AutolevParser ( Parser ):
grammarFileName = "Autolev.g4"
atn = ATNDeserializer().deserialize(serializedATN())
decisionsToDFA = [ DFA(ds, i) for i, ds in enumerate(atn.decisionToState) ]
sharedContextCache = PredictionContextCache()
literalNames = [ "<INVALID>", "'['", "']'", "'='", "'+='", "'-='", "':='",
"'*='", "'/='", "'^='", "','", "'''", "'('", "')'",
"'{'", "'}'", "':'", "'+'", "'-'", "';'", "'.'", "'>'",
"'0>'", "'1>>'", "'^'", "'*'", "'/'" ]
symbolicNames = [ "<INVALID>", "<INVALID>", "<INVALID>", "<INVALID>",
"<INVALID>", "<INVALID>", "<INVALID>", "<INVALID>",
"<INVALID>", "<INVALID>", "<INVALID>", "<INVALID>",
"<INVALID>", "<INVALID>", "<INVALID>", "<INVALID>",
"<INVALID>", "<INVALID>", "<INVALID>", "<INVALID>",
"<INVALID>", "<INVALID>", "<INVALID>", "<INVALID>",
"<INVALID>", "<INVALID>", "<INVALID>", "Mass", "Inertia",
"Input", "Output", "Save", "UnitSystem", "Encode",
"Newtonian", "Frames", "Bodies", "Particles", "Points",
"Constants", "Specifieds", "Imaginary", "Variables",
"MotionVariables", "INT", "FLOAT", "EXP", "LINE_COMMENT",
"ID", "WS" ]
RULE_prog = 0
RULE_stat = 1
RULE_assignment = 2
RULE_equals = 3
RULE_index = 4
RULE_diff = 5
RULE_functionCall = 6
RULE_varDecl = 7
RULE_varType = 8
RULE_varDecl2 = 9
RULE_ranges = 10
RULE_massDecl = 11
RULE_massDecl2 = 12
RULE_inertiaDecl = 13
RULE_matrix = 14
RULE_matrixInOutput = 15
RULE_codeCommands = 16
RULE_settings = 17
RULE_units = 18
RULE_inputs = 19
RULE_id_diff = 20
RULE_inputs2 = 21
RULE_outputs = 22
RULE_outputs2 = 23
RULE_codegen = 24
RULE_commands = 25
RULE_vec = 26
RULE_expr = 27
ruleNames = [ "prog", "stat", "assignment", "equals", "index", "diff",
"functionCall", "varDecl", "varType", "varDecl2", "ranges",
"massDecl", "massDecl2", "inertiaDecl", "matrix", "matrixInOutput",
"codeCommands", "settings", "units", "inputs", "id_diff",
"inputs2", "outputs", "outputs2", "codegen", "commands",
"vec", "expr" ]
EOF = Token.EOF
T__0=1
T__1=2
T__2=3
T__3=4
T__4=5
T__5=6
T__6=7
T__7=8
T__8=9
T__9=10
T__10=11
T__11=12
T__12=13
T__13=14
T__14=15
T__15=16
T__16=17
T__17=18
T__18=19
T__19=20
T__20=21
T__21=22
T__22=23
T__23=24
T__24=25
T__25=26
Mass=27
Inertia=28
Input=29
Output=30
Save=31
UnitSystem=32
Encode=33
Newtonian=34
Frames=35
Bodies=36
Particles=37
Points=38
Constants=39
Specifieds=40
Imaginary=41
Variables=42
MotionVariables=43
INT=44
FLOAT=45
EXP=46
LINE_COMMENT=47
ID=48
WS=49
def __init__(self, input:TokenStream, output:TextIO = sys.stdout):
super().__init__(input, output)
self.checkVersion("4.11.1")
self._interp = ParserATNSimulator(self, self.atn, self.decisionsToDFA, self.sharedContextCache)
self._predicates = None
class ProgContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def stat(self, i:int=None):
if i is None:
return self.getTypedRuleContexts(AutolevParser.StatContext)
else:
return self.getTypedRuleContext(AutolevParser.StatContext,i)
def getRuleIndex(self):
return AutolevParser.RULE_prog
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterProg" ):
listener.enterProg(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitProg" ):
listener.exitProg(self)
def prog(self):
localctx = AutolevParser.ProgContext(self, self._ctx, self.state)
self.enterRule(localctx, 0, self.RULE_prog)
self._la = 0 # Token type
try:
self.enterOuterAlt(localctx, 1)
self.state = 57
self._errHandler.sync(self)
_la = self._input.LA(1)
while True:
self.state = 56
self.stat()
self.state = 59
self._errHandler.sync(self)
_la = self._input.LA(1)
if not (((_la) & ~0x3f) == 0 and ((1 << _la) & 299067041120256) != 0):
break
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class StatContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def varDecl(self):
return self.getTypedRuleContext(AutolevParser.VarDeclContext,0)
def functionCall(self):
return self.getTypedRuleContext(AutolevParser.FunctionCallContext,0)
def codeCommands(self):
return self.getTypedRuleContext(AutolevParser.CodeCommandsContext,0)
def massDecl(self):
return self.getTypedRuleContext(AutolevParser.MassDeclContext,0)
def inertiaDecl(self):
return self.getTypedRuleContext(AutolevParser.InertiaDeclContext,0)
def assignment(self):
return self.getTypedRuleContext(AutolevParser.AssignmentContext,0)
def settings(self):
return self.getTypedRuleContext(AutolevParser.SettingsContext,0)
def getRuleIndex(self):
return AutolevParser.RULE_stat
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterStat" ):
listener.enterStat(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitStat" ):
listener.exitStat(self)
def stat(self):
localctx = AutolevParser.StatContext(self, self._ctx, self.state)
self.enterRule(localctx, 2, self.RULE_stat)
try:
self.state = 68
self._errHandler.sync(self)
la_ = self._interp.adaptivePredict(self._input,1,self._ctx)
if la_ == 1:
self.enterOuterAlt(localctx, 1)
self.state = 61
self.varDecl()
pass
elif la_ == 2:
self.enterOuterAlt(localctx, 2)
self.state = 62
self.functionCall()
pass
elif la_ == 3:
self.enterOuterAlt(localctx, 3)
self.state = 63
self.codeCommands()
pass
elif la_ == 4:
self.enterOuterAlt(localctx, 4)
self.state = 64
self.massDecl()
pass
elif la_ == 5:
self.enterOuterAlt(localctx, 5)
self.state = 65
self.inertiaDecl()
pass
elif la_ == 6:
self.enterOuterAlt(localctx, 6)
self.state = 66
self.assignment()
pass
elif la_ == 7:
self.enterOuterAlt(localctx, 7)
self.state = 67
self.settings()
pass
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class AssignmentContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def getRuleIndex(self):
return AutolevParser.RULE_assignment
def copyFrom(self, ctx:ParserRuleContext):
super().copyFrom(ctx)
class VecAssignContext(AssignmentContext):
def __init__(self, parser, ctx:ParserRuleContext): # actually a AutolevParser.AssignmentContext
super().__init__(parser)
self.copyFrom(ctx)
def vec(self):
return self.getTypedRuleContext(AutolevParser.VecContext,0)
def equals(self):
return self.getTypedRuleContext(AutolevParser.EqualsContext,0)
def expr(self):
return self.getTypedRuleContext(AutolevParser.ExprContext,0)
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterVecAssign" ):
listener.enterVecAssign(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitVecAssign" ):
listener.exitVecAssign(self)
class RegularAssignContext(AssignmentContext):
def __init__(self, parser, ctx:ParserRuleContext): # actually a AutolevParser.AssignmentContext
super().__init__(parser)
self.copyFrom(ctx)
def ID(self):
return self.getToken(AutolevParser.ID, 0)
def equals(self):
return self.getTypedRuleContext(AutolevParser.EqualsContext,0)
def expr(self):
return self.getTypedRuleContext(AutolevParser.ExprContext,0)
def diff(self):
return self.getTypedRuleContext(AutolevParser.DiffContext,0)
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterRegularAssign" ):
listener.enterRegularAssign(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitRegularAssign" ):
listener.exitRegularAssign(self)
class IndexAssignContext(AssignmentContext):
def __init__(self, parser, ctx:ParserRuleContext): # actually a AutolevParser.AssignmentContext
super().__init__(parser)
self.copyFrom(ctx)
def ID(self):
return self.getToken(AutolevParser.ID, 0)
def index(self):
return self.getTypedRuleContext(AutolevParser.IndexContext,0)
def equals(self):
return self.getTypedRuleContext(AutolevParser.EqualsContext,0)
def expr(self):
return self.getTypedRuleContext(AutolevParser.ExprContext,0)
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterIndexAssign" ):
listener.enterIndexAssign(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitIndexAssign" ):
listener.exitIndexAssign(self)
def assignment(self):
localctx = AutolevParser.AssignmentContext(self, self._ctx, self.state)
self.enterRule(localctx, 4, self.RULE_assignment)
self._la = 0 # Token type
try:
self.state = 88
self._errHandler.sync(self)
la_ = self._interp.adaptivePredict(self._input,3,self._ctx)
if la_ == 1:
localctx = AutolevParser.VecAssignContext(self, localctx)
self.enterOuterAlt(localctx, 1)
self.state = 70
self.vec()
self.state = 71
self.equals()
self.state = 72
self.expr(0)
pass
elif la_ == 2:
localctx = AutolevParser.IndexAssignContext(self, localctx)
self.enterOuterAlt(localctx, 2)
self.state = 74
self.match(AutolevParser.ID)
self.state = 75
self.match(AutolevParser.T__0)
self.state = 76
self.index()
self.state = 77
self.match(AutolevParser.T__1)
self.state = 78
self.equals()
self.state = 79
self.expr(0)
pass
elif la_ == 3:
localctx = AutolevParser.RegularAssignContext(self, localctx)
self.enterOuterAlt(localctx, 3)
self.state = 81
self.match(AutolevParser.ID)
self.state = 83
self._errHandler.sync(self)
_la = self._input.LA(1)
if _la==11:
self.state = 82
self.diff()
self.state = 85
self.equals()
self.state = 86
self.expr(0)
pass
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class EqualsContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def getRuleIndex(self):
return AutolevParser.RULE_equals
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterEquals" ):
listener.enterEquals(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitEquals" ):
listener.exitEquals(self)
def equals(self):
localctx = AutolevParser.EqualsContext(self, self._ctx, self.state)
self.enterRule(localctx, 6, self.RULE_equals)
self._la = 0 # Token type
try:
self.enterOuterAlt(localctx, 1)
self.state = 90
_la = self._input.LA(1)
if not(((_la) & ~0x3f) == 0 and ((1 << _la) & 1016) != 0):
self._errHandler.recoverInline(self)
else:
self._errHandler.reportMatch(self)
self.consume()
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class IndexContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def expr(self, i:int=None):
if i is None:
return self.getTypedRuleContexts(AutolevParser.ExprContext)
else:
return self.getTypedRuleContext(AutolevParser.ExprContext,i)
def getRuleIndex(self):
return AutolevParser.RULE_index
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterIndex" ):
listener.enterIndex(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitIndex" ):
listener.exitIndex(self)
def index(self):
localctx = AutolevParser.IndexContext(self, self._ctx, self.state)
self.enterRule(localctx, 8, self.RULE_index)
self._la = 0 # Token type
try:
self.enterOuterAlt(localctx, 1)
self.state = 92
self.expr(0)
self.state = 97
self._errHandler.sync(self)
_la = self._input.LA(1)
while _la==10:
self.state = 93
self.match(AutolevParser.T__9)
self.state = 94
self.expr(0)
self.state = 99
self._errHandler.sync(self)
_la = self._input.LA(1)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class DiffContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def getRuleIndex(self):
return AutolevParser.RULE_diff
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterDiff" ):
listener.enterDiff(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitDiff" ):
listener.exitDiff(self)
def diff(self):
localctx = AutolevParser.DiffContext(self, self._ctx, self.state)
self.enterRule(localctx, 10, self.RULE_diff)
self._la = 0 # Token type
try:
self.enterOuterAlt(localctx, 1)
self.state = 101
self._errHandler.sync(self)
_la = self._input.LA(1)
while True:
self.state = 100
self.match(AutolevParser.T__10)
self.state = 103
self._errHandler.sync(self)
_la = self._input.LA(1)
if not (_la==11):
break
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class FunctionCallContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def ID(self, i:int=None):
if i is None:
return self.getTokens(AutolevParser.ID)
else:
return self.getToken(AutolevParser.ID, i)
def expr(self, i:int=None):
if i is None:
return self.getTypedRuleContexts(AutolevParser.ExprContext)
else:
return self.getTypedRuleContext(AutolevParser.ExprContext,i)
def Mass(self):
return self.getToken(AutolevParser.Mass, 0)
def Inertia(self):
return self.getToken(AutolevParser.Inertia, 0)
def getRuleIndex(self):
return AutolevParser.RULE_functionCall
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterFunctionCall" ):
listener.enterFunctionCall(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitFunctionCall" ):
listener.exitFunctionCall(self)
def functionCall(self):
localctx = AutolevParser.FunctionCallContext(self, self._ctx, self.state)
self.enterRule(localctx, 12, self.RULE_functionCall)
self._la = 0 # Token type
try:
self.state = 131
self._errHandler.sync(self)
token = self._input.LA(1)
if token in [48]:
self.enterOuterAlt(localctx, 1)
self.state = 105
self.match(AutolevParser.ID)
self.state = 106
self.match(AutolevParser.T__11)
self.state = 115
self._errHandler.sync(self)
_la = self._input.LA(1)
if ((_la) & ~0x3f) == 0 and ((1 << _la) & 404620694540290) != 0:
self.state = 107
self.expr(0)
self.state = 112
self._errHandler.sync(self)
_la = self._input.LA(1)
while _la==10:
self.state = 108
self.match(AutolevParser.T__9)
self.state = 109
self.expr(0)
self.state = 114
self._errHandler.sync(self)
_la = self._input.LA(1)
self.state = 117
self.match(AutolevParser.T__12)
pass
elif token in [27, 28]:
self.enterOuterAlt(localctx, 2)
self.state = 118
_la = self._input.LA(1)
if not(_la==27 or _la==28):
self._errHandler.recoverInline(self)
else:
self._errHandler.reportMatch(self)
self.consume()
self.state = 119
self.match(AutolevParser.T__11)
self.state = 128
self._errHandler.sync(self)
_la = self._input.LA(1)
if _la==48:
self.state = 120
self.match(AutolevParser.ID)
self.state = 125
self._errHandler.sync(self)
_la = self._input.LA(1)
while _la==10:
self.state = 121
self.match(AutolevParser.T__9)
self.state = 122
self.match(AutolevParser.ID)
self.state = 127
self._errHandler.sync(self)
_la = self._input.LA(1)
self.state = 130
self.match(AutolevParser.T__12)
pass
else:
raise NoViableAltException(self)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class VarDeclContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def varType(self):
return self.getTypedRuleContext(AutolevParser.VarTypeContext,0)
def varDecl2(self, i:int=None):
if i is None:
return self.getTypedRuleContexts(AutolevParser.VarDecl2Context)
else:
return self.getTypedRuleContext(AutolevParser.VarDecl2Context,i)
def getRuleIndex(self):
return AutolevParser.RULE_varDecl
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterVarDecl" ):
listener.enterVarDecl(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitVarDecl" ):
listener.exitVarDecl(self)
def varDecl(self):
localctx = AutolevParser.VarDeclContext(self, self._ctx, self.state)
self.enterRule(localctx, 14, self.RULE_varDecl)
self._la = 0 # Token type
try:
self.enterOuterAlt(localctx, 1)
self.state = 133
self.varType()
self.state = 134
self.varDecl2()
self.state = 139
self._errHandler.sync(self)
_la = self._input.LA(1)
while _la==10:
self.state = 135
self.match(AutolevParser.T__9)
self.state = 136
self.varDecl2()
self.state = 141
self._errHandler.sync(self)
_la = self._input.LA(1)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class VarTypeContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def Newtonian(self):
return self.getToken(AutolevParser.Newtonian, 0)
def Frames(self):
return self.getToken(AutolevParser.Frames, 0)
def Bodies(self):
return self.getToken(AutolevParser.Bodies, 0)
def Particles(self):
return self.getToken(AutolevParser.Particles, 0)
def Points(self):
return self.getToken(AutolevParser.Points, 0)
def Constants(self):
return self.getToken(AutolevParser.Constants, 0)
def Specifieds(self):
return self.getToken(AutolevParser.Specifieds, 0)
def Imaginary(self):
return self.getToken(AutolevParser.Imaginary, 0)
def Variables(self):
return self.getToken(AutolevParser.Variables, 0)
def MotionVariables(self):
return self.getToken(AutolevParser.MotionVariables, 0)
def getRuleIndex(self):
return AutolevParser.RULE_varType
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterVarType" ):
listener.enterVarType(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitVarType" ):
listener.exitVarType(self)
def varType(self):
localctx = AutolevParser.VarTypeContext(self, self._ctx, self.state)
self.enterRule(localctx, 16, self.RULE_varType)
self._la = 0 # Token type
try:
self.state = 164
self._errHandler.sync(self)
token = self._input.LA(1)
if token in [34]:
self.enterOuterAlt(localctx, 1)
self.state = 142
self.match(AutolevParser.Newtonian)
pass
elif token in [35]:
self.enterOuterAlt(localctx, 2)
self.state = 143
self.match(AutolevParser.Frames)
pass
elif token in [36]:
self.enterOuterAlt(localctx, 3)
self.state = 144
self.match(AutolevParser.Bodies)
pass
elif token in [37]:
self.enterOuterAlt(localctx, 4)
self.state = 145
self.match(AutolevParser.Particles)
pass
elif token in [38]:
self.enterOuterAlt(localctx, 5)
self.state = 146
self.match(AutolevParser.Points)
pass
elif token in [39]:
self.enterOuterAlt(localctx, 6)
self.state = 147
self.match(AutolevParser.Constants)
pass
elif token in [40]:
self.enterOuterAlt(localctx, 7)
self.state = 148
self.match(AutolevParser.Specifieds)
pass
elif token in [41]:
self.enterOuterAlt(localctx, 8)
self.state = 149
self.match(AutolevParser.Imaginary)
pass
elif token in [42]:
self.enterOuterAlt(localctx, 9)
self.state = 150
self.match(AutolevParser.Variables)
self.state = 154
self._errHandler.sync(self)
_la = self._input.LA(1)
while _la==11:
self.state = 151
self.match(AutolevParser.T__10)
self.state = 156
self._errHandler.sync(self)
_la = self._input.LA(1)
pass
elif token in [43]:
self.enterOuterAlt(localctx, 10)
self.state = 157
self.match(AutolevParser.MotionVariables)
self.state = 161
self._errHandler.sync(self)
_la = self._input.LA(1)
while _la==11:
self.state = 158
self.match(AutolevParser.T__10)
self.state = 163
self._errHandler.sync(self)
_la = self._input.LA(1)
pass
else:
raise NoViableAltException(self)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class VarDecl2Context(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def ID(self):
return self.getToken(AutolevParser.ID, 0)
def INT(self, i:int=None):
if i is None:
return self.getTokens(AutolevParser.INT)
else:
return self.getToken(AutolevParser.INT, i)
def expr(self):
return self.getTypedRuleContext(AutolevParser.ExprContext,0)
def getRuleIndex(self):
return AutolevParser.RULE_varDecl2
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterVarDecl2" ):
listener.enterVarDecl2(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitVarDecl2" ):
listener.exitVarDecl2(self)
def varDecl2(self):
localctx = AutolevParser.VarDecl2Context(self, self._ctx, self.state)
self.enterRule(localctx, 18, self.RULE_varDecl2)
self._la = 0 # Token type
try:
self.enterOuterAlt(localctx, 1)
self.state = 166
self.match(AutolevParser.ID)
self.state = 172
self._errHandler.sync(self)
la_ = self._interp.adaptivePredict(self._input,15,self._ctx)
if la_ == 1:
self.state = 167
self.match(AutolevParser.T__13)
self.state = 168
self.match(AutolevParser.INT)
self.state = 169
self.match(AutolevParser.T__9)
self.state = 170
self.match(AutolevParser.INT)
self.state = 171
self.match(AutolevParser.T__14)
self.state = 188
self._errHandler.sync(self)
la_ = self._interp.adaptivePredict(self._input,17,self._ctx)
if la_ == 1:
self.state = 174
self.match(AutolevParser.T__13)
self.state = 175
self.match(AutolevParser.INT)
self.state = 176
self.match(AutolevParser.T__15)
self.state = 177
self.match(AutolevParser.INT)
self.state = 184
self._errHandler.sync(self)
_la = self._input.LA(1)
while _la==10:
self.state = 178
self.match(AutolevParser.T__9)
self.state = 179
self.match(AutolevParser.INT)
self.state = 180
self.match(AutolevParser.T__15)
self.state = 181
self.match(AutolevParser.INT)
self.state = 186
self._errHandler.sync(self)
_la = self._input.LA(1)
self.state = 187
self.match(AutolevParser.T__14)
self.state = 193
self._errHandler.sync(self)
_la = self._input.LA(1)
if _la==14:
self.state = 190
self.match(AutolevParser.T__13)
self.state = 191
self.match(AutolevParser.INT)
self.state = 192
self.match(AutolevParser.T__14)
self.state = 196
self._errHandler.sync(self)
_la = self._input.LA(1)
if _la==17 or _la==18:
self.state = 195
_la = self._input.LA(1)
if not(_la==17 or _la==18):
self._errHandler.recoverInline(self)
else:
self._errHandler.reportMatch(self)
self.consume()
self.state = 201
self._errHandler.sync(self)
_la = self._input.LA(1)
while _la==11:
self.state = 198
self.match(AutolevParser.T__10)
self.state = 203
self._errHandler.sync(self)
_la = self._input.LA(1)
self.state = 206
self._errHandler.sync(self)
_la = self._input.LA(1)
if _la==3:
self.state = 204
self.match(AutolevParser.T__2)
self.state = 205
self.expr(0)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class RangesContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def INT(self, i:int=None):
if i is None:
return self.getTokens(AutolevParser.INT)
else:
return self.getToken(AutolevParser.INT, i)
def getRuleIndex(self):
return AutolevParser.RULE_ranges
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterRanges" ):
listener.enterRanges(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitRanges" ):
listener.exitRanges(self)
def ranges(self):
localctx = AutolevParser.RangesContext(self, self._ctx, self.state)
self.enterRule(localctx, 20, self.RULE_ranges)
self._la = 0 # Token type
try:
self.enterOuterAlt(localctx, 1)
self.state = 208
self.match(AutolevParser.T__13)
self.state = 209
self.match(AutolevParser.INT)
self.state = 210
self.match(AutolevParser.T__15)
self.state = 211
self.match(AutolevParser.INT)
self.state = 218
self._errHandler.sync(self)
_la = self._input.LA(1)
while _la==10:
self.state = 212
self.match(AutolevParser.T__9)
self.state = 213
self.match(AutolevParser.INT)
self.state = 214
self.match(AutolevParser.T__15)
self.state = 215
self.match(AutolevParser.INT)
self.state = 220
self._errHandler.sync(self)
_la = self._input.LA(1)
self.state = 221
self.match(AutolevParser.T__14)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class MassDeclContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def Mass(self):
return self.getToken(AutolevParser.Mass, 0)
def massDecl2(self, i:int=None):
if i is None:
return self.getTypedRuleContexts(AutolevParser.MassDecl2Context)
else:
return self.getTypedRuleContext(AutolevParser.MassDecl2Context,i)
def getRuleIndex(self):
return AutolevParser.RULE_massDecl
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterMassDecl" ):
listener.enterMassDecl(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitMassDecl" ):
listener.exitMassDecl(self)
def massDecl(self):
localctx = AutolevParser.MassDeclContext(self, self._ctx, self.state)
self.enterRule(localctx, 22, self.RULE_massDecl)
self._la = 0 # Token type
try:
self.enterOuterAlt(localctx, 1)
self.state = 223
self.match(AutolevParser.Mass)
self.state = 224
self.massDecl2()
self.state = 229
self._errHandler.sync(self)
_la = self._input.LA(1)
while _la==10:
self.state = 225
self.match(AutolevParser.T__9)
self.state = 226
self.massDecl2()
self.state = 231
self._errHandler.sync(self)
_la = self._input.LA(1)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class MassDecl2Context(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def ID(self):
return self.getToken(AutolevParser.ID, 0)
def expr(self):
return self.getTypedRuleContext(AutolevParser.ExprContext,0)
def getRuleIndex(self):
return AutolevParser.RULE_massDecl2
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterMassDecl2" ):
listener.enterMassDecl2(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitMassDecl2" ):
listener.exitMassDecl2(self)
def massDecl2(self):
localctx = AutolevParser.MassDecl2Context(self, self._ctx, self.state)
self.enterRule(localctx, 24, self.RULE_massDecl2)
try:
self.enterOuterAlt(localctx, 1)
self.state = 232
self.match(AutolevParser.ID)
self.state = 233
self.match(AutolevParser.T__2)
self.state = 234
self.expr(0)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class InertiaDeclContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def Inertia(self):
return self.getToken(AutolevParser.Inertia, 0)
def ID(self, i:int=None):
if i is None:
return self.getTokens(AutolevParser.ID)
else:
return self.getToken(AutolevParser.ID, i)
def expr(self, i:int=None):
if i is None:
return self.getTypedRuleContexts(AutolevParser.ExprContext)
else:
return self.getTypedRuleContext(AutolevParser.ExprContext,i)
def getRuleIndex(self):
return AutolevParser.RULE_inertiaDecl
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterInertiaDecl" ):
listener.enterInertiaDecl(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitInertiaDecl" ):
listener.exitInertiaDecl(self)
def inertiaDecl(self):
localctx = AutolevParser.InertiaDeclContext(self, self._ctx, self.state)
self.enterRule(localctx, 26, self.RULE_inertiaDecl)
self._la = 0 # Token type
try:
self.enterOuterAlt(localctx, 1)
self.state = 236
self.match(AutolevParser.Inertia)
self.state = 237
self.match(AutolevParser.ID)
self.state = 241
self._errHandler.sync(self)
_la = self._input.LA(1)
if _la==12:
self.state = 238
self.match(AutolevParser.T__11)
self.state = 239
self.match(AutolevParser.ID)
self.state = 240
self.match(AutolevParser.T__12)
self.state = 245
self._errHandler.sync(self)
_la = self._input.LA(1)
while True:
self.state = 243
self.match(AutolevParser.T__9)
self.state = 244
self.expr(0)
self.state = 247
self._errHandler.sync(self)
_la = self._input.LA(1)
if not (_la==10):
break
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class MatrixContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def expr(self, i:int=None):
if i is None:
return self.getTypedRuleContexts(AutolevParser.ExprContext)
else:
return self.getTypedRuleContext(AutolevParser.ExprContext,i)
def getRuleIndex(self):
return AutolevParser.RULE_matrix
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterMatrix" ):
listener.enterMatrix(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitMatrix" ):
listener.exitMatrix(self)
def matrix(self):
localctx = AutolevParser.MatrixContext(self, self._ctx, self.state)
self.enterRule(localctx, 28, self.RULE_matrix)
self._la = 0 # Token type
try:
self.enterOuterAlt(localctx, 1)
self.state = 249
self.match(AutolevParser.T__0)
self.state = 250
self.expr(0)
self.state = 255
self._errHandler.sync(self)
_la = self._input.LA(1)
while _la==10 or _la==19:
self.state = 251
_la = self._input.LA(1)
if not(_la==10 or _la==19):
self._errHandler.recoverInline(self)
else:
self._errHandler.reportMatch(self)
self.consume()
self.state = 252
self.expr(0)
self.state = 257
self._errHandler.sync(self)
_la = self._input.LA(1)
self.state = 258
self.match(AutolevParser.T__1)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class MatrixInOutputContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def ID(self, i:int=None):
if i is None:
return self.getTokens(AutolevParser.ID)
else:
return self.getToken(AutolevParser.ID, i)
def FLOAT(self):
return self.getToken(AutolevParser.FLOAT, 0)
def INT(self):
return self.getToken(AutolevParser.INT, 0)
def getRuleIndex(self):
return AutolevParser.RULE_matrixInOutput
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterMatrixInOutput" ):
listener.enterMatrixInOutput(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitMatrixInOutput" ):
listener.exitMatrixInOutput(self)
def matrixInOutput(self):
localctx = AutolevParser.MatrixInOutputContext(self, self._ctx, self.state)
self.enterRule(localctx, 30, self.RULE_matrixInOutput)
self._la = 0 # Token type
try:
self.state = 268
self._errHandler.sync(self)
token = self._input.LA(1)
if token in [48]:
self.enterOuterAlt(localctx, 1)
self.state = 260
self.match(AutolevParser.ID)
self.state = 261
self.match(AutolevParser.ID)
self.state = 262
self.match(AutolevParser.T__2)
self.state = 264
self._errHandler.sync(self)
_la = self._input.LA(1)
if _la==44 or _la==45:
self.state = 263
_la = self._input.LA(1)
if not(_la==44 or _la==45):
self._errHandler.recoverInline(self)
else:
self._errHandler.reportMatch(self)
self.consume()
pass
elif token in [45]:
self.enterOuterAlt(localctx, 2)
self.state = 266
self.match(AutolevParser.FLOAT)
pass
elif token in [44]:
self.enterOuterAlt(localctx, 3)
self.state = 267
self.match(AutolevParser.INT)
pass
else:
raise NoViableAltException(self)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class CodeCommandsContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def units(self):
return self.getTypedRuleContext(AutolevParser.UnitsContext,0)
def inputs(self):
return self.getTypedRuleContext(AutolevParser.InputsContext,0)
def outputs(self):
return self.getTypedRuleContext(AutolevParser.OutputsContext,0)
def codegen(self):
return self.getTypedRuleContext(AutolevParser.CodegenContext,0)
def commands(self):
return self.getTypedRuleContext(AutolevParser.CommandsContext,0)
def getRuleIndex(self):
return AutolevParser.RULE_codeCommands
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterCodeCommands" ):
listener.enterCodeCommands(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitCodeCommands" ):
listener.exitCodeCommands(self)
def codeCommands(self):
localctx = AutolevParser.CodeCommandsContext(self, self._ctx, self.state)
self.enterRule(localctx, 32, self.RULE_codeCommands)
try:
self.state = 275
self._errHandler.sync(self)
token = self._input.LA(1)
if token in [32]:
self.enterOuterAlt(localctx, 1)
self.state = 270
self.units()
pass
elif token in [29]:
self.enterOuterAlt(localctx, 2)
self.state = 271
self.inputs()
pass
elif token in [30]:
self.enterOuterAlt(localctx, 3)
self.state = 272
self.outputs()
pass
elif token in [48]:
self.enterOuterAlt(localctx, 4)
self.state = 273
self.codegen()
pass
elif token in [31, 33]:
self.enterOuterAlt(localctx, 5)
self.state = 274
self.commands()
pass
else:
raise NoViableAltException(self)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class SettingsContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def ID(self, i:int=None):
if i is None:
return self.getTokens(AutolevParser.ID)
else:
return self.getToken(AutolevParser.ID, i)
def EXP(self):
return self.getToken(AutolevParser.EXP, 0)
def FLOAT(self):
return self.getToken(AutolevParser.FLOAT, 0)
def INT(self):
return self.getToken(AutolevParser.INT, 0)
def getRuleIndex(self):
return AutolevParser.RULE_settings
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterSettings" ):
listener.enterSettings(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitSettings" ):
listener.exitSettings(self)
def settings(self):
localctx = AutolevParser.SettingsContext(self, self._ctx, self.state)
self.enterRule(localctx, 34, self.RULE_settings)
self._la = 0 # Token type
try:
self.enterOuterAlt(localctx, 1)
self.state = 277
self.match(AutolevParser.ID)
self.state = 279
self._errHandler.sync(self)
la_ = self._interp.adaptivePredict(self._input,30,self._ctx)
if la_ == 1:
self.state = 278
_la = self._input.LA(1)
if not(((_la) & ~0x3f) == 0 and ((1 << _la) & 404620279021568) != 0):
self._errHandler.recoverInline(self)
else:
self._errHandler.reportMatch(self)
self.consume()
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class UnitsContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def UnitSystem(self):
return self.getToken(AutolevParser.UnitSystem, 0)
def ID(self, i:int=None):
if i is None:
return self.getTokens(AutolevParser.ID)
else:
return self.getToken(AutolevParser.ID, i)
def getRuleIndex(self):
return AutolevParser.RULE_units
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterUnits" ):
listener.enterUnits(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitUnits" ):
listener.exitUnits(self)
def units(self):
localctx = AutolevParser.UnitsContext(self, self._ctx, self.state)
self.enterRule(localctx, 36, self.RULE_units)
self._la = 0 # Token type
try:
self.enterOuterAlt(localctx, 1)
self.state = 281
self.match(AutolevParser.UnitSystem)
self.state = 282
self.match(AutolevParser.ID)
self.state = 287
self._errHandler.sync(self)
_la = self._input.LA(1)
while _la==10:
self.state = 283
self.match(AutolevParser.T__9)
self.state = 284
self.match(AutolevParser.ID)
self.state = 289
self._errHandler.sync(self)
_la = self._input.LA(1)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class InputsContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def Input(self):
return self.getToken(AutolevParser.Input, 0)
def inputs2(self, i:int=None):
if i is None:
return self.getTypedRuleContexts(AutolevParser.Inputs2Context)
else:
return self.getTypedRuleContext(AutolevParser.Inputs2Context,i)
def getRuleIndex(self):
return AutolevParser.RULE_inputs
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterInputs" ):
listener.enterInputs(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitInputs" ):
listener.exitInputs(self)
def inputs(self):
localctx = AutolevParser.InputsContext(self, self._ctx, self.state)
self.enterRule(localctx, 38, self.RULE_inputs)
self._la = 0 # Token type
try:
self.enterOuterAlt(localctx, 1)
self.state = 290
self.match(AutolevParser.Input)
self.state = 291
self.inputs2()
self.state = 296
self._errHandler.sync(self)
_la = self._input.LA(1)
while _la==10:
self.state = 292
self.match(AutolevParser.T__9)
self.state = 293
self.inputs2()
self.state = 298
self._errHandler.sync(self)
_la = self._input.LA(1)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class Id_diffContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def ID(self):
return self.getToken(AutolevParser.ID, 0)
def diff(self):
return self.getTypedRuleContext(AutolevParser.DiffContext,0)
def getRuleIndex(self):
return AutolevParser.RULE_id_diff
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterId_diff" ):
listener.enterId_diff(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitId_diff" ):
listener.exitId_diff(self)
def id_diff(self):
localctx = AutolevParser.Id_diffContext(self, self._ctx, self.state)
self.enterRule(localctx, 40, self.RULE_id_diff)
self._la = 0 # Token type
try:
self.enterOuterAlt(localctx, 1)
self.state = 299
self.match(AutolevParser.ID)
self.state = 301
self._errHandler.sync(self)
_la = self._input.LA(1)
if _la==11:
self.state = 300
self.diff()
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class Inputs2Context(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def id_diff(self):
return self.getTypedRuleContext(AutolevParser.Id_diffContext,0)
def expr(self, i:int=None):
if i is None:
return self.getTypedRuleContexts(AutolevParser.ExprContext)
else:
return self.getTypedRuleContext(AutolevParser.ExprContext,i)
def getRuleIndex(self):
return AutolevParser.RULE_inputs2
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterInputs2" ):
listener.enterInputs2(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitInputs2" ):
listener.exitInputs2(self)
def inputs2(self):
localctx = AutolevParser.Inputs2Context(self, self._ctx, self.state)
self.enterRule(localctx, 42, self.RULE_inputs2)
try:
self.enterOuterAlt(localctx, 1)
self.state = 303
self.id_diff()
self.state = 304
self.match(AutolevParser.T__2)
self.state = 305
self.expr(0)
self.state = 307
self._errHandler.sync(self)
la_ = self._interp.adaptivePredict(self._input,34,self._ctx)
if la_ == 1:
self.state = 306
self.expr(0)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class OutputsContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def Output(self):
return self.getToken(AutolevParser.Output, 0)
def outputs2(self, i:int=None):
if i is None:
return self.getTypedRuleContexts(AutolevParser.Outputs2Context)
else:
return self.getTypedRuleContext(AutolevParser.Outputs2Context,i)
def getRuleIndex(self):
return AutolevParser.RULE_outputs
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterOutputs" ):
listener.enterOutputs(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitOutputs" ):
listener.exitOutputs(self)
def outputs(self):
localctx = AutolevParser.OutputsContext(self, self._ctx, self.state)
self.enterRule(localctx, 44, self.RULE_outputs)
self._la = 0 # Token type
try:
self.enterOuterAlt(localctx, 1)
self.state = 309
self.match(AutolevParser.Output)
self.state = 310
self.outputs2()
self.state = 315
self._errHandler.sync(self)
_la = self._input.LA(1)
while _la==10:
self.state = 311
self.match(AutolevParser.T__9)
self.state = 312
self.outputs2()
self.state = 317
self._errHandler.sync(self)
_la = self._input.LA(1)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class Outputs2Context(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def expr(self, i:int=None):
if i is None:
return self.getTypedRuleContexts(AutolevParser.ExprContext)
else:
return self.getTypedRuleContext(AutolevParser.ExprContext,i)
def getRuleIndex(self):
return AutolevParser.RULE_outputs2
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterOutputs2" ):
listener.enterOutputs2(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitOutputs2" ):
listener.exitOutputs2(self)
def outputs2(self):
localctx = AutolevParser.Outputs2Context(self, self._ctx, self.state)
self.enterRule(localctx, 46, self.RULE_outputs2)
try:
self.enterOuterAlt(localctx, 1)
self.state = 318
self.expr(0)
self.state = 320
self._errHandler.sync(self)
la_ = self._interp.adaptivePredict(self._input,36,self._ctx)
if la_ == 1:
self.state = 319
self.expr(0)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class CodegenContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def ID(self, i:int=None):
if i is None:
return self.getTokens(AutolevParser.ID)
else:
return self.getToken(AutolevParser.ID, i)
def functionCall(self):
return self.getTypedRuleContext(AutolevParser.FunctionCallContext,0)
def matrixInOutput(self, i:int=None):
if i is None:
return self.getTypedRuleContexts(AutolevParser.MatrixInOutputContext)
else:
return self.getTypedRuleContext(AutolevParser.MatrixInOutputContext,i)
def getRuleIndex(self):
return AutolevParser.RULE_codegen
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterCodegen" ):
listener.enterCodegen(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitCodegen" ):
listener.exitCodegen(self)
def codegen(self):
localctx = AutolevParser.CodegenContext(self, self._ctx, self.state)
self.enterRule(localctx, 48, self.RULE_codegen)
self._la = 0 # Token type
try:
self.enterOuterAlt(localctx, 1)
self.state = 322
self.match(AutolevParser.ID)
self.state = 323
self.functionCall()
self.state = 335
self._errHandler.sync(self)
_la = self._input.LA(1)
if _la==1:
self.state = 324
self.match(AutolevParser.T__0)
self.state = 325
self.matrixInOutput()
self.state = 330
self._errHandler.sync(self)
_la = self._input.LA(1)
while _la==10:
self.state = 326
self.match(AutolevParser.T__9)
self.state = 327
self.matrixInOutput()
self.state = 332
self._errHandler.sync(self)
_la = self._input.LA(1)
self.state = 333
self.match(AutolevParser.T__1)
self.state = 337
self.match(AutolevParser.ID)
self.state = 338
self.match(AutolevParser.T__19)
self.state = 339
self.match(AutolevParser.ID)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class CommandsContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def Save(self):
return self.getToken(AutolevParser.Save, 0)
def ID(self, i:int=None):
if i is None:
return self.getTokens(AutolevParser.ID)
else:
return self.getToken(AutolevParser.ID, i)
def Encode(self):
return self.getToken(AutolevParser.Encode, 0)
def getRuleIndex(self):
return AutolevParser.RULE_commands
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterCommands" ):
listener.enterCommands(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitCommands" ):
listener.exitCommands(self)
def commands(self):
localctx = AutolevParser.CommandsContext(self, self._ctx, self.state)
self.enterRule(localctx, 50, self.RULE_commands)
self._la = 0 # Token type
try:
self.state = 354
self._errHandler.sync(self)
token = self._input.LA(1)
if token in [31]:
self.enterOuterAlt(localctx, 1)
self.state = 341
self.match(AutolevParser.Save)
self.state = 342
self.match(AutolevParser.ID)
self.state = 343
self.match(AutolevParser.T__19)
self.state = 344
self.match(AutolevParser.ID)
pass
elif token in [33]:
self.enterOuterAlt(localctx, 2)
self.state = 345
self.match(AutolevParser.Encode)
self.state = 346
self.match(AutolevParser.ID)
self.state = 351
self._errHandler.sync(self)
_la = self._input.LA(1)
while _la==10:
self.state = 347
self.match(AutolevParser.T__9)
self.state = 348
self.match(AutolevParser.ID)
self.state = 353
self._errHandler.sync(self)
_la = self._input.LA(1)
pass
else:
raise NoViableAltException(self)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class VecContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def ID(self):
return self.getToken(AutolevParser.ID, 0)
def getRuleIndex(self):
return AutolevParser.RULE_vec
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterVec" ):
listener.enterVec(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitVec" ):
listener.exitVec(self)
def vec(self):
localctx = AutolevParser.VecContext(self, self._ctx, self.state)
self.enterRule(localctx, 52, self.RULE_vec)
try:
self.state = 364
self._errHandler.sync(self)
token = self._input.LA(1)
if token in [48]:
self.enterOuterAlt(localctx, 1)
self.state = 356
self.match(AutolevParser.ID)
self.state = 358
self._errHandler.sync(self)
_alt = 1
while _alt!=2 and _alt!=ATN.INVALID_ALT_NUMBER:
if _alt == 1:
self.state = 357
self.match(AutolevParser.T__20)
else:
raise NoViableAltException(self)
self.state = 360
self._errHandler.sync(self)
_alt = self._interp.adaptivePredict(self._input,41,self._ctx)
pass
elif token in [22]:
self.enterOuterAlt(localctx, 2)
self.state = 362
self.match(AutolevParser.T__21)
pass
elif token in [23]:
self.enterOuterAlt(localctx, 3)
self.state = 363
self.match(AutolevParser.T__22)
pass
else:
raise NoViableAltException(self)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class ExprContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def getRuleIndex(self):
return AutolevParser.RULE_expr
def copyFrom(self, ctx:ParserRuleContext):
super().copyFrom(ctx)
class ParensContext(ExprContext):
def __init__(self, parser, ctx:ParserRuleContext): # actually a AutolevParser.ExprContext
super().__init__(parser)
self.copyFrom(ctx)
def expr(self):
return self.getTypedRuleContext(AutolevParser.ExprContext,0)
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterParens" ):
listener.enterParens(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitParens" ):
listener.exitParens(self)
class VectorOrDyadicContext(ExprContext):
def __init__(self, parser, ctx:ParserRuleContext): # actually a AutolevParser.ExprContext
super().__init__(parser)
self.copyFrom(ctx)
def vec(self):
return self.getTypedRuleContext(AutolevParser.VecContext,0)
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterVectorOrDyadic" ):
listener.enterVectorOrDyadic(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitVectorOrDyadic" ):
listener.exitVectorOrDyadic(self)
class ExponentContext(ExprContext):
def __init__(self, parser, ctx:ParserRuleContext): # actually a AutolevParser.ExprContext
super().__init__(parser)
self.copyFrom(ctx)
def expr(self, i:int=None):
if i is None:
return self.getTypedRuleContexts(AutolevParser.ExprContext)
else:
return self.getTypedRuleContext(AutolevParser.ExprContext,i)
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterExponent" ):
listener.enterExponent(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitExponent" ):
listener.exitExponent(self)
class MulDivContext(ExprContext):
def __init__(self, parser, ctx:ParserRuleContext): # actually a AutolevParser.ExprContext
super().__init__(parser)
self.copyFrom(ctx)
def expr(self, i:int=None):
if i is None:
return self.getTypedRuleContexts(AutolevParser.ExprContext)
else:
return self.getTypedRuleContext(AutolevParser.ExprContext,i)
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterMulDiv" ):
listener.enterMulDiv(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitMulDiv" ):
listener.exitMulDiv(self)
class AddSubContext(ExprContext):
def __init__(self, parser, ctx:ParserRuleContext): # actually a AutolevParser.ExprContext
super().__init__(parser)
self.copyFrom(ctx)
def expr(self, i:int=None):
if i is None:
return self.getTypedRuleContexts(AutolevParser.ExprContext)
else:
return self.getTypedRuleContext(AutolevParser.ExprContext,i)
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterAddSub" ):
listener.enterAddSub(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitAddSub" ):
listener.exitAddSub(self)
class FloatContext(ExprContext):
def __init__(self, parser, ctx:ParserRuleContext): # actually a AutolevParser.ExprContext
super().__init__(parser)
self.copyFrom(ctx)
def FLOAT(self):
return self.getToken(AutolevParser.FLOAT, 0)
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterFloat" ):
listener.enterFloat(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitFloat" ):
listener.exitFloat(self)
class IntContext(ExprContext):
def __init__(self, parser, ctx:ParserRuleContext): # actually a AutolevParser.ExprContext
super().__init__(parser)
self.copyFrom(ctx)
def INT(self):
return self.getToken(AutolevParser.INT, 0)
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterInt" ):
listener.enterInt(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitInt" ):
listener.exitInt(self)
class IdEqualsExprContext(ExprContext):
def __init__(self, parser, ctx:ParserRuleContext): # actually a AutolevParser.ExprContext
super().__init__(parser)
self.copyFrom(ctx)
def expr(self, i:int=None):
if i is None:
return self.getTypedRuleContexts(AutolevParser.ExprContext)
else:
return self.getTypedRuleContext(AutolevParser.ExprContext,i)
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterIdEqualsExpr" ):
listener.enterIdEqualsExpr(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitIdEqualsExpr" ):
listener.exitIdEqualsExpr(self)
class NegativeOneContext(ExprContext):
def __init__(self, parser, ctx:ParserRuleContext): # actually a AutolevParser.ExprContext
super().__init__(parser)
self.copyFrom(ctx)
def expr(self):
return self.getTypedRuleContext(AutolevParser.ExprContext,0)
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterNegativeOne" ):
listener.enterNegativeOne(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitNegativeOne" ):
listener.exitNegativeOne(self)
class FunctionContext(ExprContext):
def __init__(self, parser, ctx:ParserRuleContext): # actually a AutolevParser.ExprContext
super().__init__(parser)
self.copyFrom(ctx)
def functionCall(self):
return self.getTypedRuleContext(AutolevParser.FunctionCallContext,0)
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterFunction" ):
listener.enterFunction(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitFunction" ):
listener.exitFunction(self)
class RangessContext(ExprContext):
def __init__(self, parser, ctx:ParserRuleContext): # actually a AutolevParser.ExprContext
super().__init__(parser)
self.copyFrom(ctx)
def ranges(self):
return self.getTypedRuleContext(AutolevParser.RangesContext,0)
def ID(self):
return self.getToken(AutolevParser.ID, 0)
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterRangess" ):
listener.enterRangess(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitRangess" ):
listener.exitRangess(self)
class ColonContext(ExprContext):
def __init__(self, parser, ctx:ParserRuleContext): # actually a AutolevParser.ExprContext
super().__init__(parser)
self.copyFrom(ctx)
def expr(self, i:int=None):
if i is None:
return self.getTypedRuleContexts(AutolevParser.ExprContext)
else:
return self.getTypedRuleContext(AutolevParser.ExprContext,i)
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterColon" ):
listener.enterColon(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitColon" ):
listener.exitColon(self)
class IdContext(ExprContext):
def __init__(self, parser, ctx:ParserRuleContext): # actually a AutolevParser.ExprContext
super().__init__(parser)
self.copyFrom(ctx)
def ID(self):
return self.getToken(AutolevParser.ID, 0)
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterId" ):
listener.enterId(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitId" ):
listener.exitId(self)
class ExpContext(ExprContext):
def __init__(self, parser, ctx:ParserRuleContext): # actually a AutolevParser.ExprContext
super().__init__(parser)
self.copyFrom(ctx)
def EXP(self):
return self.getToken(AutolevParser.EXP, 0)
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterExp" ):
listener.enterExp(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitExp" ):
listener.exitExp(self)
class MatricesContext(ExprContext):
def __init__(self, parser, ctx:ParserRuleContext): # actually a AutolevParser.ExprContext
super().__init__(parser)
self.copyFrom(ctx)
def matrix(self):
return self.getTypedRuleContext(AutolevParser.MatrixContext,0)
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterMatrices" ):
listener.enterMatrices(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitMatrices" ):
listener.exitMatrices(self)
class IndexingContext(ExprContext):
def __init__(self, parser, ctx:ParserRuleContext): # actually a AutolevParser.ExprContext
super().__init__(parser)
self.copyFrom(ctx)
def ID(self):
return self.getToken(AutolevParser.ID, 0)
def expr(self, i:int=None):
if i is None:
return self.getTypedRuleContexts(AutolevParser.ExprContext)
else:
return self.getTypedRuleContext(AutolevParser.ExprContext,i)
def enterRule(self, listener:ParseTreeListener):
if hasattr( listener, "enterIndexing" ):
listener.enterIndexing(self)
def exitRule(self, listener:ParseTreeListener):
if hasattr( listener, "exitIndexing" ):
listener.exitIndexing(self)
def expr(self, _p:int=0):
_parentctx = self._ctx
_parentState = self.state
localctx = AutolevParser.ExprContext(self, self._ctx, _parentState)
_prevctx = localctx
_startState = 54
self.enterRecursionRule(localctx, 54, self.RULE_expr, _p)
self._la = 0 # Token type
try:
self.enterOuterAlt(localctx, 1)
self.state = 408
self._errHandler.sync(self)
la_ = self._interp.adaptivePredict(self._input,47,self._ctx)
if la_ == 1:
localctx = AutolevParser.ExpContext(self, localctx)
self._ctx = localctx
_prevctx = localctx
self.state = 367
self.match(AutolevParser.EXP)
pass
elif la_ == 2:
localctx = AutolevParser.NegativeOneContext(self, localctx)
self._ctx = localctx
_prevctx = localctx
self.state = 368
self.match(AutolevParser.T__17)
self.state = 369
self.expr(12)
pass
elif la_ == 3:
localctx = AutolevParser.FloatContext(self, localctx)
self._ctx = localctx
_prevctx = localctx
self.state = 370
self.match(AutolevParser.FLOAT)
pass
elif la_ == 4:
localctx = AutolevParser.IntContext(self, localctx)
self._ctx = localctx
_prevctx = localctx
self.state = 371
self.match(AutolevParser.INT)
pass
elif la_ == 5:
localctx = AutolevParser.IdContext(self, localctx)
self._ctx = localctx
_prevctx = localctx
self.state = 372
self.match(AutolevParser.ID)
self.state = 376
self._errHandler.sync(self)
_alt = self._interp.adaptivePredict(self._input,43,self._ctx)
while _alt!=2 and _alt!=ATN.INVALID_ALT_NUMBER:
if _alt==1:
self.state = 373
self.match(AutolevParser.T__10)
self.state = 378
self._errHandler.sync(self)
_alt = self._interp.adaptivePredict(self._input,43,self._ctx)
pass
elif la_ == 6:
localctx = AutolevParser.VectorOrDyadicContext(self, localctx)
self._ctx = localctx
_prevctx = localctx
self.state = 379
self.vec()
pass
elif la_ == 7:
localctx = AutolevParser.IndexingContext(self, localctx)
self._ctx = localctx
_prevctx = localctx
self.state = 380
self.match(AutolevParser.ID)
self.state = 381
self.match(AutolevParser.T__0)
self.state = 382
self.expr(0)
self.state = 387
self._errHandler.sync(self)
_la = self._input.LA(1)
while _la==10:
self.state = 383
self.match(AutolevParser.T__9)
self.state = 384
self.expr(0)
self.state = 389
self._errHandler.sync(self)
_la = self._input.LA(1)
self.state = 390
self.match(AutolevParser.T__1)
pass
elif la_ == 8:
localctx = AutolevParser.FunctionContext(self, localctx)
self._ctx = localctx
_prevctx = localctx
self.state = 392
self.functionCall()
pass
elif la_ == 9:
localctx = AutolevParser.MatricesContext(self, localctx)
self._ctx = localctx
_prevctx = localctx
self.state = 393
self.matrix()
pass
elif la_ == 10:
localctx = AutolevParser.ParensContext(self, localctx)
self._ctx = localctx
_prevctx = localctx
self.state = 394
self.match(AutolevParser.T__11)
self.state = 395
self.expr(0)
self.state = 396
self.match(AutolevParser.T__12)
pass
elif la_ == 11:
localctx = AutolevParser.RangessContext(self, localctx)
self._ctx = localctx
_prevctx = localctx
self.state = 399
self._errHandler.sync(self)
_la = self._input.LA(1)
if _la==48:
self.state = 398
self.match(AutolevParser.ID)
self.state = 401
self.ranges()
self.state = 405
self._errHandler.sync(self)
_alt = self._interp.adaptivePredict(self._input,46,self._ctx)
while _alt!=2 and _alt!=ATN.INVALID_ALT_NUMBER:
if _alt==1:
self.state = 402
self.match(AutolevParser.T__10)
self.state = 407
self._errHandler.sync(self)
_alt = self._interp.adaptivePredict(self._input,46,self._ctx)
pass
self._ctx.stop = self._input.LT(-1)
self.state = 427
self._errHandler.sync(self)
_alt = self._interp.adaptivePredict(self._input,49,self._ctx)
while _alt!=2 and _alt!=ATN.INVALID_ALT_NUMBER:
if _alt==1:
if self._parseListeners is not None:
self.triggerExitRuleEvent()
_prevctx = localctx
self.state = 425
self._errHandler.sync(self)
la_ = self._interp.adaptivePredict(self._input,48,self._ctx)
if la_ == 1:
localctx = AutolevParser.ExponentContext(self, AutolevParser.ExprContext(self, _parentctx, _parentState))
self.pushNewRecursionContext(localctx, _startState, self.RULE_expr)
self.state = 410
if not self.precpred(self._ctx, 16):
from antlr4.error.Errors import FailedPredicateException
raise FailedPredicateException(self, "self.precpred(self._ctx, 16)")
self.state = 411
self.match(AutolevParser.T__23)
self.state = 412
self.expr(17)
pass
elif la_ == 2:
localctx = AutolevParser.MulDivContext(self, AutolevParser.ExprContext(self, _parentctx, _parentState))
self.pushNewRecursionContext(localctx, _startState, self.RULE_expr)
self.state = 413
if not self.precpred(self._ctx, 15):
from antlr4.error.Errors import FailedPredicateException
raise FailedPredicateException(self, "self.precpred(self._ctx, 15)")
self.state = 414
_la = self._input.LA(1)
if not(_la==25 or _la==26):
self._errHandler.recoverInline(self)
else:
self._errHandler.reportMatch(self)
self.consume()
self.state = 415
self.expr(16)
pass
elif la_ == 3:
localctx = AutolevParser.AddSubContext(self, AutolevParser.ExprContext(self, _parentctx, _parentState))
self.pushNewRecursionContext(localctx, _startState, self.RULE_expr)
self.state = 416
if not self.precpred(self._ctx, 14):
from antlr4.error.Errors import FailedPredicateException
raise FailedPredicateException(self, "self.precpred(self._ctx, 14)")
self.state = 417
_la = self._input.LA(1)
if not(_la==17 or _la==18):
self._errHandler.recoverInline(self)
else:
self._errHandler.reportMatch(self)
self.consume()
self.state = 418
self.expr(15)
pass
elif la_ == 4:
localctx = AutolevParser.IdEqualsExprContext(self, AutolevParser.ExprContext(self, _parentctx, _parentState))
self.pushNewRecursionContext(localctx, _startState, self.RULE_expr)
self.state = 419
if not self.precpred(self._ctx, 3):
from antlr4.error.Errors import FailedPredicateException
raise FailedPredicateException(self, "self.precpred(self._ctx, 3)")
self.state = 420
self.match(AutolevParser.T__2)
self.state = 421
self.expr(4)
pass
elif la_ == 5:
localctx = AutolevParser.ColonContext(self, AutolevParser.ExprContext(self, _parentctx, _parentState))
self.pushNewRecursionContext(localctx, _startState, self.RULE_expr)
self.state = 422
if not self.precpred(self._ctx, 2):
from antlr4.error.Errors import FailedPredicateException
raise FailedPredicateException(self, "self.precpred(self._ctx, 2)")
self.state = 423
self.match(AutolevParser.T__15)
self.state = 424
self.expr(3)
pass
self.state = 429
self._errHandler.sync(self)
_alt = self._interp.adaptivePredict(self._input,49,self._ctx)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.unrollRecursionContexts(_parentctx)
return localctx
def sempred(self, localctx:RuleContext, ruleIndex:int, predIndex:int):
if self._predicates == None:
self._predicates = dict()
self._predicates[27] = self.expr_sempred
pred = self._predicates.get(ruleIndex, None)
if pred is None:
raise Exception("No predicate with index:" + str(ruleIndex))
else:
return pred(localctx, predIndex)
def expr_sempred(self, localctx:ExprContext, predIndex:int):
if predIndex == 0:
return self.precpred(self._ctx, 16)
if predIndex == 1:
return self.precpred(self._ctx, 15)
if predIndex == 2:
return self.precpred(self._ctx, 14)
if predIndex == 3:
return self.precpred(self._ctx, 3)
if predIndex == 4:
return self.precpred(self._ctx, 2)
PK ]ZZZ�=j . sympy/parsing/autolev/test-examples/README.txt# parsing/tests/test_autolev.py uses the .al files in this directory as inputs and checks
# the equivalence of the parser generated codes and the respective .py files.
# By default, this directory contains tests for all rules of the parser.
# Additional tests consisting of full physics examples shall be made available soon in
# the form of another repository. One shall be able to copy the contents of that repo
# to this folder and use those tests after uncommenting the respective code in
# parsing/tests/test_autolev.py.
PK ]ZZZ@O�� � 0 sympy/parsing/autolev/test-examples/ruletest1.al% ruletest1.al
CONSTANTS F = 3, G = 9.81
CONSTANTS A, B
CONSTANTS S, S1, S2+, S3+, S4-
CONSTANTS K{4}, L{1:3}, P{1:2,1:3}
CONSTANTS C{2,3}
E1 = A*F + S2 - G
E2 = F^2 + K3*K2*G
PK ]ZZZ�r b+ + 0 sympy/parsing/autolev/test-examples/ruletest1.pyimport sympy.physics.mechanics as _me
import sympy as _sm
import math as m
import numpy as _np
f = _sm.S(3)
g = _sm.S(9.81)
a, b = _sm.symbols('a b', real=True)
s, s1 = _sm.symbols('s s1', real=True)
s2, s3 = _sm.symbols('s2 s3', real=True, nonnegative=True)
s4 = _sm.symbols('s4', real=True, nonpositive=True)
k1, k2, k3, k4, l1, l2, l3, p11, p12, p13, p21, p22, p23 = _sm.symbols('k1 k2 k3 k4 l1 l2 l3 p11 p12 p13 p21 p22 p23', real=True)
c11, c12, c13, c21, c22, c23 = _sm.symbols('c11 c12 c13 c21 c22 c23', real=True)
e1 = a*f+s2-g
e2 = f**2+k3*k2*g
PK ]ZZZ/�qS
1 sympy/parsing/autolev/test-examples/ruletest10.al% ruletest10.al
VARIABLES X,Y
COMPLEX ON
CONSTANTS A,B
E = A*(B*X+Y)^2
M = [E;E]
EXPAND(E)
EXPAND(M)
FACTOR(E,X)
FACTOR(M,X)
EQN[1] = A*X + B*Y
EQN[2] = 2*A*X - 3*B*Y
SOLVE(EQN, X, Y)
RHS_Y = RHS(Y)
E = (X+Y)^2 + 2*X^2
ARRANGE(E, 2, X)
CONSTANTS A,B,C
M = [A,B;C,0]
M2 = EVALUATE(M,A=1,B=2,C=3)
EIG(M2, EIGVALUE, EIGVEC)
NEWTONIAN N
FRAMES A
SIMPROT(N, A, N1>, X)
DEGREES OFF
SIMPROT(N, A, N1>, PI/2)
CONSTANTS C{3}
V> = C1*A1> + C2*A2> + C3*A3>
POINTS O, P
P_P_O> = C1*A1>
EXPRESS(V>,N)
EXPRESS(P_P_O>,N)
W_A_N> = C3*A3>
ANGVEL(A,N)
V2PTS(N,A,O,P)
PARTICLES P{2}
V2PTS(N,A,P1,P2)
A2PTS(N,A,P1,P)
BODIES B{2}
CONSTANT G
GRAVITY(G*N1>)
VARIABLE Z
V> = X*A1> + Y*A3>
P_P_O> = X*A1> + Y*A2>
X = 2*Z
Y = Z
EXPLICIT(V>)
EXPLICIT(P_P_O>)
FORCE(O/P1, X*Y*A1>)
FORCE(P2, X*Y*A1>)
PK ]ZZZ0:��
�
1 sympy/parsing/autolev/test-examples/ruletest10.pyimport sympy.physics.mechanics as _me
import sympy as _sm
import math as m
import numpy as _np
x, y = _me.dynamicsymbols('x y')
a, b = _sm.symbols('a b', real=True)
e = a*(b*x+y)**2
m = _sm.Matrix([e,e]).reshape(2, 1)
e = e.expand()
m = _sm.Matrix([i.expand() for i in m]).reshape((m).shape[0], (m).shape[1])
e = _sm.factor(e, x)
m = _sm.Matrix([_sm.factor(i,x) for i in m]).reshape((m).shape[0], (m).shape[1])
eqn = _sm.Matrix([[0]])
eqn[0] = a*x+b*y
eqn = eqn.row_insert(eqn.shape[0], _sm.Matrix([[0]]))
eqn[eqn.shape[0]-1] = 2*a*x-3*b*y
print(_sm.solve(eqn,x,y))
rhs_y = _sm.solve(eqn,x,y)[y]
e = (x+y)**2+2*x**2
e.collect(x)
a, b, c = _sm.symbols('a b c', real=True)
m = _sm.Matrix([a,b,c,0]).reshape(2, 2)
m2 = _sm.Matrix([i.subs({a:1,b:2,c:3}) for i in m]).reshape((m).shape[0], (m).shape[1])
eigvalue = _sm.Matrix([i.evalf() for i in (m2).eigenvals().keys()])
eigvec = _sm.Matrix([i[2][0].evalf() for i in (m2).eigenvects()]).reshape(m2.shape[0], m2.shape[1])
frame_n = _me.ReferenceFrame('n')
frame_a = _me.ReferenceFrame('a')
frame_a.orient(frame_n, 'Axis', [x, frame_n.x])
frame_a.orient(frame_n, 'Axis', [_sm.pi/2, frame_n.x])
c1, c2, c3 = _sm.symbols('c1 c2 c3', real=True)
v = c1*frame_a.x+c2*frame_a.y+c3*frame_a.z
point_o = _me.Point('o')
point_p = _me.Point('p')
point_o.set_pos(point_p, c1*frame_a.x)
v = (v).express(frame_n)
point_o.set_pos(point_p, (point_o.pos_from(point_p)).express(frame_n))
frame_a.set_ang_vel(frame_n, c3*frame_a.z)
print(frame_n.ang_vel_in(frame_a))
point_p.v2pt_theory(point_o,frame_n,frame_a)
particle_p1 = _me.Particle('p1', _me.Point('p1_pt'), _sm.Symbol('m'))
particle_p2 = _me.Particle('p2', _me.Point('p2_pt'), _sm.Symbol('m'))
particle_p2.point.v2pt_theory(particle_p1.point,frame_n,frame_a)
point_p.a2pt_theory(particle_p1.point,frame_n,frame_a)
body_b1_cm = _me.Point('b1_cm')
body_b1_cm.set_vel(frame_n, 0)
body_b1_f = _me.ReferenceFrame('b1_f')
body_b1 = _me.RigidBody('b1', body_b1_cm, body_b1_f, _sm.symbols('m'), (_me.outer(body_b1_f.x,body_b1_f.x),body_b1_cm))
body_b2_cm = _me.Point('b2_cm')
body_b2_cm.set_vel(frame_n, 0)
body_b2_f = _me.ReferenceFrame('b2_f')
body_b2 = _me.RigidBody('b2', body_b2_cm, body_b2_f, _sm.symbols('m'), (_me.outer(body_b2_f.x,body_b2_f.x),body_b2_cm))
g = _sm.symbols('g', real=True)
force_p1 = particle_p1.mass*(g*frame_n.x)
force_p2 = particle_p2.mass*(g*frame_n.x)
force_b1 = body_b1.mass*(g*frame_n.x)
force_b2 = body_b2.mass*(g*frame_n.x)
z = _me.dynamicsymbols('z')
v = x*frame_a.x+y*frame_a.z
point_o.set_pos(point_p, x*frame_a.x+y*frame_a.y)
v = (v).subs({x:2*z, y:z})
point_o.set_pos(point_p, (point_o.pos_from(point_p)).subs({x:2*z, y:z}))
force_o = -1*(x*y*frame_a.x)
force_p1 = particle_p1.mass*(g*frame_n.x)+ x*y*frame_a.x
PK ]ZZZGEw�� � 1 sympy/parsing/autolev/test-examples/ruletest11.alVARIABLES X, Y
CONSTANTS A{1:2, 1:2}, B{1:2}
EQN[1] = A11*x + A12*y - B1
EQN[2] = A21*x + A22*y - B2
INPUT A11=2, A12=5, A21=3, A22=4, B1=7, B2=6
CODE ALGEBRAIC(EQN, X, Y) some_filename.c
PK ]ZZZ�.!�� � 1 sympy/parsing/autolev/test-examples/ruletest11.pyimport sympy.physics.mechanics as _me
import sympy as _sm
import math as m
import numpy as _np
x, y = _me.dynamicsymbols('x y')
a11, a12, a21, a22, b1, b2 = _sm.symbols('a11 a12 a21 a22 b1 b2', real=True)
eqn = _sm.Matrix([[0]])
eqn[0] = a11*x+a12*y-b1
eqn = eqn.row_insert(eqn.shape[0], _sm.Matrix([[0]]))
eqn[eqn.shape[0]-1] = a21*x+a22*y-b2
eqn_list = []
for i in eqn: eqn_list.append(i.subs({a11:2, a12:5, a21:3, a22:4, b1:7, b2:6}))
print(_sm.linsolve(eqn_list, x,y))
PK ]ZZZM4J� � 1 sympy/parsing/autolev/test-examples/ruletest12.alVARIABLES X,Y
CONSTANTS A,B,R
EQN[1] = A*X^3+B*Y^2-R
EQN[2] = A*SIN(X)^2 + B*COS(2*Y) - R^2
INPUT A=2.0, B=3.0, R=1.0
INPUT X = 30 DEG, Y = 3.14
CODE NONLINEAR(EQN,X,Y) some_filename.c
PK ]ZZZ�uQF� � 1 sympy/parsing/autolev/test-examples/ruletest12.pyimport sympy.physics.mechanics as _me
import sympy as _sm
import math as m
import numpy as _np
x, y = _me.dynamicsymbols('x y')
a, b, r = _sm.symbols('a b r', real=True)
eqn = _sm.Matrix([[0]])
eqn[0] = a*x**3+b*y**2-r
eqn = eqn.row_insert(eqn.shape[0], _sm.Matrix([[0]]))
eqn[eqn.shape[0]-1] = a*_sm.sin(x)**2+b*_sm.cos(2*y)-r**2
matrix_list = []
for i in eqn:matrix_list.append(i.subs({a:2.0, b:3.0, r:1.0}))
print(_sm.nsolve(matrix_list,(x,y),(_np.deg2rad(30),3.14)))
PK ]ZZZ�_=� � 0 sympy/parsing/autolev/test-examples/ruletest2.al% ruletest2.al
VARIABLES X1,X2
SPECIFIED F1 = X1*X2 + 3*X1^2
SPECIFIED F2=X1*T+X2*T^2
VARIABLE X', Y''
MOTIONVARIABLES Q{3}, U{2}
VARIABLES P{2}'
VARIABLE W{3}', R{2}''
VARIABLES C{1:2, 1:2}
VARIABLES D{1,3}
VARIABLES J{1:2}
IMAGINARY N
PK ]ZZZ ��4 4 0 sympy/parsing/autolev/test-examples/ruletest2.pyimport sympy.physics.mechanics as _me
import sympy as _sm
import math as m
import numpy as _np
x1, x2 = _me.dynamicsymbols('x1 x2')
f1 = x1*x2+3*x1**2
f2 = x1*_me.dynamicsymbols._t+x2*_me.dynamicsymbols._t**2
x, y = _me.dynamicsymbols('x y')
x_d, y_d = _me.dynamicsymbols('x_ y_', 1)
y_dd = _me.dynamicsymbols('y_', 2)
q1, q2, q3, u1, u2 = _me.dynamicsymbols('q1 q2 q3 u1 u2')
p1, p2 = _me.dynamicsymbols('p1 p2')
p1_d, p2_d = _me.dynamicsymbols('p1_ p2_', 1)
w1, w2, w3, r1, r2 = _me.dynamicsymbols('w1 w2 w3 r1 r2')
w1_d, w2_d, w3_d, r1_d, r2_d = _me.dynamicsymbols('w1_ w2_ w3_ r1_ r2_', 1)
r1_dd, r2_dd = _me.dynamicsymbols('r1_ r2_', 2)
c11, c12, c21, c22 = _me.dynamicsymbols('c11 c12 c21 c22')
d11, d12, d13 = _me.dynamicsymbols('d11 d12 d13')
j1, j2 = _me.dynamicsymbols('j1 j2')
n = _sm.symbols('n')
n = _sm.I
PK ]ZZZ�i�4 4 0 sympy/parsing/autolev/test-examples/ruletest3.al% ruletest3.al
FRAMES A, B
NEWTONIAN N
VARIABLES X{3}
CONSTANTS L
V1> = X1*A1> + X2*A2> + X3*A3>
V2> = X1*B1> + X2*B2> + X3*B3>
V3> = X1*N1> + X2*N2> + X3*N3>
V> = V1> + V2> + V3>
POINTS C, D
POINTS PO{3}
PARTICLES L
PARTICLES P{3}
BODIES S
BODIES R{2}
V4> = X1*S1> + X2*S2> + X3*S3>
P_C_SO> = L*N1>
PK ]ZZZ�Q�& & 0 sympy/parsing/autolev/test-examples/ruletest3.pyimport sympy.physics.mechanics as _me
import sympy as _sm
import math as m
import numpy as _np
frame_a = _me.ReferenceFrame('a')
frame_b = _me.ReferenceFrame('b')
frame_n = _me.ReferenceFrame('n')
x1, x2, x3 = _me.dynamicsymbols('x1 x2 x3')
l = _sm.symbols('l', real=True)
v1 = x1*frame_a.x+x2*frame_a.y+x3*frame_a.z
v2 = x1*frame_b.x+x2*frame_b.y+x3*frame_b.z
v3 = x1*frame_n.x+x2*frame_n.y+x3*frame_n.z
v = v1+v2+v3
point_c = _me.Point('c')
point_d = _me.Point('d')
point_po1 = _me.Point('po1')
point_po2 = _me.Point('po2')
point_po3 = _me.Point('po3')
particle_l = _me.Particle('l', _me.Point('l_pt'), _sm.Symbol('m'))
particle_p1 = _me.Particle('p1', _me.Point('p1_pt'), _sm.Symbol('m'))
particle_p2 = _me.Particle('p2', _me.Point('p2_pt'), _sm.Symbol('m'))
particle_p3 = _me.Particle('p3', _me.Point('p3_pt'), _sm.Symbol('m'))
body_s_cm = _me.Point('s_cm')
body_s_cm.set_vel(frame_n, 0)
body_s_f = _me.ReferenceFrame('s_f')
body_s = _me.RigidBody('s', body_s_cm, body_s_f, _sm.symbols('m'), (_me.outer(body_s_f.x,body_s_f.x),body_s_cm))
body_r1_cm = _me.Point('r1_cm')
body_r1_cm.set_vel(frame_n, 0)
body_r1_f = _me.ReferenceFrame('r1_f')
body_r1 = _me.RigidBody('r1', body_r1_cm, body_r1_f, _sm.symbols('m'), (_me.outer(body_r1_f.x,body_r1_f.x),body_r1_cm))
body_r2_cm = _me.Point('r2_cm')
body_r2_cm.set_vel(frame_n, 0)
body_r2_f = _me.ReferenceFrame('r2_f')
body_r2 = _me.RigidBody('r2', body_r2_cm, body_r2_f, _sm.symbols('m'), (_me.outer(body_r2_f.x,body_r2_f.x),body_r2_cm))
v4 = x1*body_s_f.x+x2*body_s_f.y+x3*body_s_f.z
body_s_cm.set_pos(point_c, l*frame_n.x)
PK ]ZZZ�4%�. . 0 sympy/parsing/autolev/test-examples/ruletest4.al% ruletest4.al
FRAMES A, B
MOTIONVARIABLES Q{3}
SIMPROT(A, B, 1, Q3)
DCM = A_B
M = DCM*3 - A_B
VARIABLES R
CIRCLE_AREA = PI*R^2
VARIABLES U, A
VARIABLES X, Y
S = U*T - 1/2*A*T^2
EXPR1 = 2*A*0.5 - 1.25 + 0.25
EXPR2 = -X^2 + Y^2 + 0.25*(X+Y)^2
EXPR3 = 0.5E-10
DYADIC>> = A1>*A1> + A2>*A2> + A3>*A3>
PK ]ZZZz-[� � 0 sympy/parsing/autolev/test-examples/ruletest4.pyimport sympy.physics.mechanics as _me
import sympy as _sm
import math as m
import numpy as _np
frame_a = _me.ReferenceFrame('a')
frame_b = _me.ReferenceFrame('b')
q1, q2, q3 = _me.dynamicsymbols('q1 q2 q3')
frame_b.orient(frame_a, 'Axis', [q3, frame_a.x])
dcm = frame_a.dcm(frame_b)
m = dcm*3-frame_a.dcm(frame_b)
r = _me.dynamicsymbols('r')
circle_area = _sm.pi*r**2
u, a = _me.dynamicsymbols('u a')
x, y = _me.dynamicsymbols('x y')
s = u*_me.dynamicsymbols._t-1/2*a*_me.dynamicsymbols._t**2
expr1 = 2*a*0.5-1.25+0.25
expr2 = -1*x**2+y**2+0.25*(x+y)**2
expr3 = 0.5*10**(-10)
dyadic = _me.outer(frame_a.x, frame_a.x)+_me.outer(frame_a.y, frame_a.y)+_me.outer(frame_a.z, frame_a.z)
PK ]ZZZt�j� 0 sympy/parsing/autolev/test-examples/ruletest5.al% ruletest5.al
VARIABLES X', Y'
E1 = (X+Y)^2 + (X-Y)^3
E2 = (X-Y)^2
E3 = X^2 + Y^2 + 2*X*Y
M1 = [E1;E2]
M2 = [(X+Y)^2,(X-Y)^2]
M3 = M1 + [X;Y]
AM = EXPAND(M1)
CM = EXPAND([(X+Y)^2,(X-Y)^2])
EM = EXPAND(M1 + [X;Y])
F = EXPAND(E1)
G = EXPAND(E2)
A = FACTOR(E3, X)
BM = FACTOR(M1, X)
CM = FACTOR(M1 + [X;Y], X)
A = D(E3, X)
B = D(E3, Y)
CM = D(M2, X)
DM = D(M1 + [X;Y], X)
FRAMES A, B
A_B = [1,0,0;1,0,0;1,0,0]
V1> = X*A1> + Y*A2> + X*Y*A3>
E> = D(V1>, X, B)
FM = DT(M1)
GM = DT([(X+Y)^2,(X-Y)^2])
H> = DT(V1>, B)
PK ]ZZZ
a�v� � 0 sympy/parsing/autolev/test-examples/ruletest5.pyimport sympy.physics.mechanics as _me
import sympy as _sm
import math as m
import numpy as _np
x, y = _me.dynamicsymbols('x y')
x_d, y_d = _me.dynamicsymbols('x_ y_', 1)
e1 = (x+y)**2+(x-y)**3
e2 = (x-y)**2
e3 = x**2+y**2+2*x*y
m1 = _sm.Matrix([e1,e2]).reshape(2, 1)
m2 = _sm.Matrix([(x+y)**2,(x-y)**2]).reshape(1, 2)
m3 = m1+_sm.Matrix([x,y]).reshape(2, 1)
am = _sm.Matrix([i.expand() for i in m1]).reshape((m1).shape[0], (m1).shape[1])
cm = _sm.Matrix([i.expand() for i in _sm.Matrix([(x+y)**2,(x-y)**2]).reshape(1, 2)]).reshape((_sm.Matrix([(x+y)**2,(x-y)**2]).reshape(1, 2)).shape[0], (_sm.Matrix([(x+y)**2,(x-y)**2]).reshape(1, 2)).shape[1])
em = _sm.Matrix([i.expand() for i in m1+_sm.Matrix([x,y]).reshape(2, 1)]).reshape((m1+_sm.Matrix([x,y]).reshape(2, 1)).shape[0], (m1+_sm.Matrix([x,y]).reshape(2, 1)).shape[1])
f = (e1).expand()
g = (e2).expand()
a = _sm.factor((e3), x)
bm = _sm.Matrix([_sm.factor(i, x) for i in m1]).reshape((m1).shape[0], (m1).shape[1])
cm = _sm.Matrix([_sm.factor(i, x) for i in m1+_sm.Matrix([x,y]).reshape(2, 1)]).reshape((m1+_sm.Matrix([x,y]).reshape(2, 1)).shape[0], (m1+_sm.Matrix([x,y]).reshape(2, 1)).shape[1])
a = (e3).diff(x)
b = (e3).diff(y)
cm = _sm.Matrix([i.diff(x) for i in m2]).reshape((m2).shape[0], (m2).shape[1])
dm = _sm.Matrix([i.diff(x) for i in m1+_sm.Matrix([x,y]).reshape(2, 1)]).reshape((m1+_sm.Matrix([x,y]).reshape(2, 1)).shape[0], (m1+_sm.Matrix([x,y]).reshape(2, 1)).shape[1])
frame_a = _me.ReferenceFrame('a')
frame_b = _me.ReferenceFrame('b')
frame_b.orient(frame_a, 'DCM', _sm.Matrix([1,0,0,1,0,0,1,0,0]).reshape(3, 3))
v1 = x*frame_a.x+y*frame_a.y+x*y*frame_a.z
e = (v1).diff(x, frame_b)
fm = _sm.Matrix([i.diff(_sm.Symbol('t')) for i in m1]).reshape((m1).shape[0], (m1).shape[1])
gm = _sm.Matrix([i.diff(_sm.Symbol('t')) for i in _sm.Matrix([(x+y)**2,(x-y)**2]).reshape(1, 2)]).reshape((_sm.Matrix([(x+y)**2,(x-y)**2]).reshape(1, 2)).shape[0], (_sm.Matrix([(x+y)**2,(x-y)**2]).reshape(1, 2)).shape[1])
h = (v1).dt(frame_b)
PK ]ZZZi:G)� � 0 sympy/parsing/autolev/test-examples/ruletest6.al% ruletest6.al
VARIABLES Q{2}
VARIABLES X,Y,Z
Q1 = X^2 + Y^2
Q2 = X-Y
E = Q1 + Q2
A = EXPLICIT(E)
E2 = COS(X)
E3 = COS(X*Y)
A = TAYLOR(E2, 0:2, X=0)
B = TAYLOR(E3, 0:2, X=0, Y=0)
E = EXPAND((X+Y)^2)
A = EVALUATE(E, X=1, Y=Z)
BM = EVALUATE([E;2*E], X=1, Y=Z)
E = Q1 + Q2
A = EVALUATE(E, X=2, Y=Z^2)
CONSTANTS J,K,L
P1 = POLYNOMIAL([J,K,L],X)
P2 = POLYNOMIAL(J*X+K,X,1)
ROOT1 = ROOTS(P1, X, 2)
ROOT2 = ROOTS([1;2;3])
M = [1,2,3,4;5,6,7,8;9,10,11,12;13,14,15,16]
AM = TRANSPOSE(M) + M
BM = EIG(M)
C1 = DIAGMAT(4, 1)
C2 = DIAGMAT(3, 4, 2)
DM = INV(M+C1)
E = DET(M+C1) + TRACE([1,0;0,1])
F = ELEMENT(M, 2, 3)
A = COLS(M)
BM = COLS(M, 1)
CM = COLS(M, 1, 2:4, 3)
DM = ROWS(M, 1)
EM = ROWS(M, 1, 2:4, 3)
PK ]ZZZ�
;� � 0 sympy/parsing/autolev/test-examples/ruletest6.pyimport sympy.physics.mechanics as _me
import sympy as _sm
import math as m
import numpy as _np
q1, q2 = _me.dynamicsymbols('q1 q2')
x, y, z = _me.dynamicsymbols('x y z')
e = q1+q2
a = (e).subs({q1:x**2+y**2, q2:x-y})
e2 = _sm.cos(x)
e3 = _sm.cos(x*y)
a = (e2).series(x, 0, 2).removeO()
b = (e3).series(x, 0, 2).removeO().series(y, 0, 2).removeO()
e = ((x+y)**2).expand()
a = (e).subs({q1:x**2+y**2,q2:x-y}).subs({x:1,y:z})
bm = _sm.Matrix([i.subs({x:1,y:z}) for i in _sm.Matrix([e,2*e]).reshape(2, 1)]).reshape((_sm.Matrix([e,2*e]).reshape(2, 1)).shape[0], (_sm.Matrix([e,2*e]).reshape(2, 1)).shape[1])
e = q1+q2
a = (e).subs({q1:x**2+y**2,q2:x-y}).subs({x:2,y:z**2})
j, k, l = _sm.symbols('j k l', real=True)
p1 = _sm.Poly(_sm.Matrix([j,k,l]).reshape(1, 3), x)
p2 = _sm.Poly(j*x+k, x)
root1 = [i.evalf() for i in _sm.solve(p1, x)]
root2 = [i.evalf() for i in _sm.solve(_sm.Poly(_sm.Matrix([1,2,3]).reshape(3, 1), x),x)]
m = _sm.Matrix([1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16]).reshape(4, 4)
am = (m).T+m
bm = _sm.Matrix([i.evalf() for i in (m).eigenvals().keys()])
c1 = _sm.diag(1,1,1,1)
c2 = _sm.Matrix([2 if i==j else 0 for i in range(3) for j in range(4)]).reshape(3, 4)
dm = (m+c1)**(-1)
e = (m+c1).det()+(_sm.Matrix([1,0,0,1]).reshape(2, 2)).trace()
f = (m)[1,2]
a = (m).cols
bm = (m).col(0)
cm = _sm.Matrix([(m).T.row(0),(m).T.row(1),(m).T.row(2),(m).T.row(3),(m).T.row(2)])
dm = (m).row(0)
em = _sm.Matrix([(m).row(0),(m).row(1),(m).row(2),(m).row(3),(m).row(2)])
PK ]ZZZش�# 0 sympy/parsing/autolev/test-examples/ruletest7.al% ruletest7.al
VARIABLES X', Y'
E = COS(X) + SIN(X) + TAN(X)&
+ COSH(X) + SINH(X) + TANH(X)&
+ ACOS(X) + ASIN(X) + ATAN(X)&
+ LOG(X) + EXP(X) + SQRT(X)&
+ FACTORIAL(X) + CEIL(X) +&
FLOOR(X) + SIGN(X)
E = SQR(X) + LOG10(X)
A = ABS(-1) + INT(1.5) + ROUND(1.9)
E1 = 2*X + 3*Y
E2 = X + Y
AM = COEF([E1;E2], [X,Y])
B = COEF(E1, X)
C = COEF(E2, Y)
D1 = EXCLUDE(E1, X)
D2 = INCLUDE(E1, X)
FM = ARRANGE([E1,E2],2,X)
F = ARRANGE(E1, 2, Y)
G = REPLACE(E1, X=2*X)
GM = REPLACE([E1;E2], X=3)
FRAMES A, B
VARIABLES THETA
SIMPROT(A,B,3,THETA)
V1> = 2*A1> - 3*A2> + A3>
V2> = B1> + B2> + B3>
A = DOT(V1>, V2>)
BM = DOT(V1>, [V2>;2*V2>])
C> = CROSS(V1>,V2>)
D = MAG(2*V1>) + MAG(3*V1>)
DYADIC>> = 3*A1>*A1> + A2>*A2> + 2*A3>*A3>
AM = MATRIX(B, DYADIC>>)
M = [1;2;3]
V> = VECTOR(A, M)
PK ]ZZZ?��D� � 0 sympy/parsing/autolev/test-examples/ruletest7.pyimport sympy.physics.mechanics as _me
import sympy as _sm
import math as m
import numpy as _np
x, y = _me.dynamicsymbols('x y')
x_d, y_d = _me.dynamicsymbols('x_ y_', 1)
e = _sm.cos(x)+_sm.sin(x)+_sm.tan(x)+_sm.cosh(x)+_sm.sinh(x)+_sm.tanh(x)+_sm.acos(x)+_sm.asin(x)+_sm.atan(x)+_sm.log(x)+_sm.exp(x)+_sm.sqrt(x)+_sm.factorial(x)+_sm.ceiling(x)+_sm.floor(x)+_sm.sign(x)
e = (x)**2+_sm.log(x, 10)
a = _sm.Abs(-1*1)+int(1.5)+round(1.9)
e1 = 2*x+3*y
e2 = x+y
am = _sm.Matrix([e1.expand().coeff(x), e1.expand().coeff(y), e2.expand().coeff(x), e2.expand().coeff(y)]).reshape(2, 2)
b = (e1).expand().coeff(x)
c = (e2).expand().coeff(y)
d1 = (e1).collect(x).coeff(x,0)
d2 = (e1).collect(x).coeff(x,1)
fm = _sm.Matrix([i.collect(x)for i in _sm.Matrix([e1,e2]).reshape(1, 2)]).reshape((_sm.Matrix([e1,e2]).reshape(1, 2)).shape[0], (_sm.Matrix([e1,e2]).reshape(1, 2)).shape[1])
f = (e1).collect(y)
g = (e1).subs({x:2*x})
gm = _sm.Matrix([i.subs({x:3}) for i in _sm.Matrix([e1,e2]).reshape(2, 1)]).reshape((_sm.Matrix([e1,e2]).reshape(2, 1)).shape[0], (_sm.Matrix([e1,e2]).reshape(2, 1)).shape[1])
frame_a = _me.ReferenceFrame('a')
frame_b = _me.ReferenceFrame('b')
theta = _me.dynamicsymbols('theta')
frame_b.orient(frame_a, 'Axis', [theta, frame_a.z])
v1 = 2*frame_a.x-3*frame_a.y+frame_a.z
v2 = frame_b.x+frame_b.y+frame_b.z
a = _me.dot(v1, v2)
bm = _sm.Matrix([_me.dot(v1, v2),_me.dot(v1, 2*v2)]).reshape(2, 1)
c = _me.cross(v1, v2)
d = 2*v1.magnitude()+3*v1.magnitude()
dyadic = _me.outer(3*frame_a.x, frame_a.x)+_me.outer(frame_a.y, frame_a.y)+_me.outer(2*frame_a.z, frame_a.z)
am = (dyadic).to_matrix(frame_b)
m = _sm.Matrix([1,2,3]).reshape(3, 1)
v = m[0]*frame_a.x +m[1]*frame_a.y +m[2]*frame_a.z
PK ]ZZZWv
� � 0 sympy/parsing/autolev/test-examples/ruletest8.al% ruletest8.al
FRAMES A
CONSTANTS C{3}
A>> = EXPRESS(1>>,A)
PARTICLES P1, P2
BODIES R
R_A = [1,1,1;1,1,0;0,0,1]
POINT O
MASS P1=M1, P2=M2, R=MR
INERTIA R, I1, I2, I3
P_P1_O> = C1*A1>
P_P2_O> = C2*A2>
P_RO_O> = C3*A3>
A>> = EXPRESS(I_P1_O>>, A)
A>> = EXPRESS(I_P2_O>>, A)
A>> = EXPRESS(I_R_O>>, A)
A>> = EXPRESS(INERTIA(O), A)
A>> = EXPRESS(INERTIA(O, P1, R), A)
A>> = EXPRESS(I_R_O>>, A)
A>> = EXPRESS(I_R_RO>>, A)
P_P1_P2> = C1*A1> + C2*A2>
P_P1_RO> = C3*A1>
P_P2_RO> = C3*A2>
B> = CM(O)
B> = CM(O, P1, R)
B> = CM(P1)
MOTIONVARIABLES U{3}
V> = U1*A1> + U2*A2> + U3*A3>
U> = UNITVEC(V> + C1*A1>)
V_P1_A> = U1*A1>
A> = PARTIALS(V_P1_A>, U1)
M = MASS(P1,R)
M = MASS(P2)
M = MASS()PK ]ZZZ�)�A�
�
0 sympy/parsing/autolev/test-examples/ruletest8.pyimport sympy.physics.mechanics as _me
import sympy as _sm
import math as m
import numpy as _np
frame_a = _me.ReferenceFrame('a')
c1, c2, c3 = _sm.symbols('c1 c2 c3', real=True)
a = _me.inertia(frame_a, 1, 1, 1)
particle_p1 = _me.Particle('p1', _me.Point('p1_pt'), _sm.Symbol('m'))
particle_p2 = _me.Particle('p2', _me.Point('p2_pt'), _sm.Symbol('m'))
body_r_cm = _me.Point('r_cm')
body_r_f = _me.ReferenceFrame('r_f')
body_r = _me.RigidBody('r', body_r_cm, body_r_f, _sm.symbols('m'), (_me.outer(body_r_f.x,body_r_f.x),body_r_cm))
frame_a.orient(body_r_f, 'DCM', _sm.Matrix([1,1,1,1,1,0,0,0,1]).reshape(3, 3))
point_o = _me.Point('o')
m1 = _sm.symbols('m1')
particle_p1.mass = m1
m2 = _sm.symbols('m2')
particle_p2.mass = m2
mr = _sm.symbols('mr')
body_r.mass = mr
i1 = _sm.symbols('i1')
i2 = _sm.symbols('i2')
i3 = _sm.symbols('i3')
body_r.inertia = (_me.inertia(body_r_f, i1, i2, i3, 0, 0, 0), body_r_cm)
point_o.set_pos(particle_p1.point, c1*frame_a.x)
point_o.set_pos(particle_p2.point, c2*frame_a.y)
point_o.set_pos(body_r_cm, c3*frame_a.z)
a = _me.inertia_of_point_mass(particle_p1.mass, particle_p1.point.pos_from(point_o), frame_a)
a = _me.inertia_of_point_mass(particle_p2.mass, particle_p2.point.pos_from(point_o), frame_a)
a = body_r.inertia[0] + _me.inertia_of_point_mass(body_r.mass, body_r.masscenter.pos_from(point_o), frame_a)
a = _me.inertia_of_point_mass(particle_p1.mass, particle_p1.point.pos_from(point_o), frame_a) + _me.inertia_of_point_mass(particle_p2.mass, particle_p2.point.pos_from(point_o), frame_a) + body_r.inertia[0] + _me.inertia_of_point_mass(body_r.mass, body_r.masscenter.pos_from(point_o), frame_a)
a = _me.inertia_of_point_mass(particle_p1.mass, particle_p1.point.pos_from(point_o), frame_a) + body_r.inertia[0] + _me.inertia_of_point_mass(body_r.mass, body_r.masscenter.pos_from(point_o), frame_a)
a = body_r.inertia[0] + _me.inertia_of_point_mass(body_r.mass, body_r.masscenter.pos_from(point_o), frame_a)
a = body_r.inertia[0]
particle_p2.point.set_pos(particle_p1.point, c1*frame_a.x+c2*frame_a.y)
body_r_cm.set_pos(particle_p1.point, c3*frame_a.x)
body_r_cm.set_pos(particle_p2.point, c3*frame_a.y)
b = _me.functions.center_of_mass(point_o,particle_p1, particle_p2, body_r)
b = _me.functions.center_of_mass(point_o,particle_p1, body_r)
b = _me.functions.center_of_mass(particle_p1.point,particle_p1, particle_p2, body_r)
u1, u2, u3 = _me.dynamicsymbols('u1 u2 u3')
v = u1*frame_a.x+u2*frame_a.y+u3*frame_a.z
u = (v+c1*frame_a.x).normalize()
particle_p1.point.set_vel(frame_a, u1*frame_a.x)
a = particle_p1.point.partial_velocity(frame_a, u1)
m = particle_p1.mass+body_r.mass
m = particle_p2.mass
m = particle_p1.mass+particle_p2.mass+body_r.mass
PK ]ZZZ�5�� � 0 sympy/parsing/autolev/test-examples/ruletest9.al% ruletest9.al
NEWTONIAN N
FRAMES A
A> = 0>
D>> = EXPRESS(1>>, A)
POINTS PO{2}
PARTICLES P{2}
MOTIONVARIABLES' C{3}'
BODIES R
P_P1_PO2> = C1*A1>
V> = 2*P_P1_PO2> + C2*A2>
W_A_N> = C3*A3>
V> = 2*W_A_N> + C2*A2>
W_R_N> = C3*A3>
V> = 2*W_R_N> + C2*A2>
ALF_A_N> = DT(W_A_N>, A)
V> = 2*ALF_A_N> + C2*A2>
V_P1_A> = C1*A1> + C3*A2>
A_RO_N> = C2*A2>
V_A> = CROSS(A_RO_N>, V_P1_A>)
X_B_C> = V_A>
X_B_D> = 2*X_B_C>
A_B_C_D_E> = X_B_D>*2
A_B_C = 2*C1*C2*C3
A_B_C += 2*C1
A_B_C := 3*C1
MOTIONVARIABLES' Q{2}', U{2}'
Q1' = U1
Q2' = U2
VARIABLES X'', Y''
SPECIFIED YY
Y'' = X*X'^2 + 1
YY = X*X'^2 + 1
M[1] = 2*X
M[2] = 2*Y
A = 2*M[1]
M = [1,2,3;4,5,6;7,8,9]
M[1, 2] = 5
A = M[1, 2]*2
FORCE_RO> = Q1*N1>
TORQUE_A> = Q2*N3>
FORCE_RO> = Q2*N2>
F> = FORCE_RO>*2
PK ]ZZZw�p,� � 0 sympy/parsing/autolev/test-examples/ruletest9.pyimport sympy.physics.mechanics as _me
import sympy as _sm
import math as m
import numpy as _np
frame_n = _me.ReferenceFrame('n')
frame_a = _me.ReferenceFrame('a')
a = 0
d = _me.inertia(frame_a, 1, 1, 1)
point_po1 = _me.Point('po1')
point_po2 = _me.Point('po2')
particle_p1 = _me.Particle('p1', _me.Point('p1_pt'), _sm.Symbol('m'))
particle_p2 = _me.Particle('p2', _me.Point('p2_pt'), _sm.Symbol('m'))
c1, c2, c3 = _me.dynamicsymbols('c1 c2 c3')
c1_d, c2_d, c3_d = _me.dynamicsymbols('c1_ c2_ c3_', 1)
body_r_cm = _me.Point('r_cm')
body_r_cm.set_vel(frame_n, 0)
body_r_f = _me.ReferenceFrame('r_f')
body_r = _me.RigidBody('r', body_r_cm, body_r_f, _sm.symbols('m'), (_me.outer(body_r_f.x,body_r_f.x),body_r_cm))
point_po2.set_pos(particle_p1.point, c1*frame_a.x)
v = 2*point_po2.pos_from(particle_p1.point)+c2*frame_a.y
frame_a.set_ang_vel(frame_n, c3*frame_a.z)
v = 2*frame_a.ang_vel_in(frame_n)+c2*frame_a.y
body_r_f.set_ang_vel(frame_n, c3*frame_a.z)
v = 2*body_r_f.ang_vel_in(frame_n)+c2*frame_a.y
frame_a.set_ang_acc(frame_n, (frame_a.ang_vel_in(frame_n)).dt(frame_a))
v = 2*frame_a.ang_acc_in(frame_n)+c2*frame_a.y
particle_p1.point.set_vel(frame_a, c1*frame_a.x+c3*frame_a.y)
body_r_cm.set_acc(frame_n, c2*frame_a.y)
v_a = _me.cross(body_r_cm.acc(frame_n), particle_p1.point.vel(frame_a))
x_b_c = v_a
x_b_d = 2*x_b_c
a_b_c_d_e = x_b_d*2
a_b_c = 2*c1*c2*c3
a_b_c += 2*c1
a_b_c = 3*c1
q1, q2, u1, u2 = _me.dynamicsymbols('q1 q2 u1 u2')
q1_d, q2_d, u1_d, u2_d = _me.dynamicsymbols('q1_ q2_ u1_ u2_', 1)
x, y = _me.dynamicsymbols('x y')
x_d, y_d = _me.dynamicsymbols('x_ y_', 1)
x_dd, y_dd = _me.dynamicsymbols('x_ y_', 2)
yy = _me.dynamicsymbols('yy')
yy = x*x_d**2+1
m = _sm.Matrix([[0]])
m[0] = 2*x
m = m.row_insert(m.shape[0], _sm.Matrix([[0]]))
m[m.shape[0]-1] = 2*y
a = 2*m[0]
m = _sm.Matrix([1,2,3,4,5,6,7,8,9]).reshape(3, 3)
m[0,1] = 5
a = m[0, 1]*2
force_ro = q1*frame_n.x
torque_a = q2*frame_n.z
force_ro = q1*frame_n.x + q2*frame_n.y
f = force_ro*2
PK ]ZZZ���� � G sympy/parsing/autolev/test-examples/pydy-example-repo/chaos_pendulum.alCONSTANTS G,LB,W,H
MOTIONVARIABLES' THETA'',PHI'',OMEGA',ALPHA'
NEWTONIAN N
BODIES A,B
SIMPROT(N,A,2,THETA)
SIMPROT(A,B,3,PHI)
POINT O
LA = (LB-H/2)/2
P_O_AO> = LA*A3>
P_O_BO> = LB*A3>
OMEGA = THETA'
ALPHA = PHI'
W_A_N> = OMEGA*N2>
W_B_A> = ALPHA*A3>
V_O_N> = 0>
V2PTS(N, A, O, AO)
V2PTS(N, A, O, BO)
MASS A=MA, B=MB
IAXX = 1/12*MA*(2*LA)^2
IAYY = IAXX
IAZZ = 0
IBXX = 1/12*MB*H^2
IBYY = 1/12*MB*(W^2+H^2)
IBZZ = 1/12*MB*W^2
INERTIA A, IAXX, IAYY, IAZZ
INERTIA B, IBXX, IBYY, IBZZ
GRAVITY(G*N3>)
ZERO = FR() + FRSTAR()
KANE()
INPUT LB=0.2,H=0.1,W=0.2,MA=0.01,MB=0.1,G=9.81
INPUT THETA = 90 DEG, PHI = 0.5 DEG, OMEGA=0, ALPHA=0
INPUT TFINAL=10, INTEGSTP=0.02
CODE DYNAMICS() some_filename.c
PK ]ZZZ�^~� � G sympy/parsing/autolev/test-examples/pydy-example-repo/chaos_pendulum.pyimport sympy.physics.mechanics as _me
import sympy as _sm
import math as m
import numpy as _np
g, lb, w, h = _sm.symbols('g lb w h', real=True)
theta, phi, omega, alpha = _me.dynamicsymbols('theta phi omega alpha')
theta_d, phi_d, omega_d, alpha_d = _me.dynamicsymbols('theta_ phi_ omega_ alpha_', 1)
theta_dd, phi_dd = _me.dynamicsymbols('theta_ phi_', 2)
frame_n = _me.ReferenceFrame('n')
body_a_cm = _me.Point('a_cm')
body_a_cm.set_vel(frame_n, 0)
body_a_f = _me.ReferenceFrame('a_f')
body_a = _me.RigidBody('a', body_a_cm, body_a_f, _sm.symbols('m'), (_me.outer(body_a_f.x,body_a_f.x),body_a_cm))
body_b_cm = _me.Point('b_cm')
body_b_cm.set_vel(frame_n, 0)
body_b_f = _me.ReferenceFrame('b_f')
body_b = _me.RigidBody('b', body_b_cm, body_b_f, _sm.symbols('m'), (_me.outer(body_b_f.x,body_b_f.x),body_b_cm))
body_a_f.orient(frame_n, 'Axis', [theta, frame_n.y])
body_b_f.orient(body_a_f, 'Axis', [phi, body_a_f.z])
point_o = _me.Point('o')
la = (lb-h/2)/2
body_a_cm.set_pos(point_o, la*body_a_f.z)
body_b_cm.set_pos(point_o, lb*body_a_f.z)
body_a_f.set_ang_vel(frame_n, omega*frame_n.y)
body_b_f.set_ang_vel(body_a_f, alpha*body_a_f.z)
point_o.set_vel(frame_n, 0)
body_a_cm.v2pt_theory(point_o,frame_n,body_a_f)
body_b_cm.v2pt_theory(point_o,frame_n,body_a_f)
ma = _sm.symbols('ma')
body_a.mass = ma
mb = _sm.symbols('mb')
body_b.mass = mb
iaxx = 1/12*ma*(2*la)**2
iayy = iaxx
iazz = 0
ibxx = 1/12*mb*h**2
ibyy = 1/12*mb*(w**2+h**2)
ibzz = 1/12*mb*w**2
body_a.inertia = (_me.inertia(body_a_f, iaxx, iayy, iazz, 0, 0, 0), body_a_cm)
body_b.inertia = (_me.inertia(body_b_f, ibxx, ibyy, ibzz, 0, 0, 0), body_b_cm)
force_a = body_a.mass*(g*frame_n.z)
force_b = body_b.mass*(g*frame_n.z)
kd_eqs = [theta_d - omega, phi_d - alpha]
forceList = [(body_a.masscenter,body_a.mass*(g*frame_n.z)), (body_b.masscenter,body_b.mass*(g*frame_n.z))]
kane = _me.KanesMethod(frame_n, q_ind=[theta,phi], u_ind=[omega, alpha], kd_eqs = kd_eqs)
fr, frstar = kane.kanes_equations([body_a, body_b], forceList)
zero = fr+frstar
from pydy.system import System
sys = System(kane, constants = {g:9.81, lb:0.2, w:0.2, h:0.1, ma:0.01, mb:0.1},
specifieds={},
initial_conditions={theta:_np.deg2rad(90), phi:_np.deg2rad(0.5), omega:0, alpha:0},
times = _np.linspace(0.0, 10, 10/0.02))
y=sys.integrate()
PK ]ZZZy��~� � H sympy/parsing/autolev/test-examples/pydy-example-repo/double_pendulum.alMOTIONVARIABLES' Q{2}', U{2}'
CONSTANTS L,M,G
NEWTONIAN N
FRAMES A,B
SIMPROT(N, A, 3, Q1)
SIMPROT(N, B, 3, Q2)
W_A_N>=U1*N3>
W_B_N>=U2*N3>
POINT O
PARTICLES P,R
P_O_P> = L*A1>
P_P_R> = L*B1>
V_O_N> = 0>
V2PTS(N, A, O, P)
V2PTS(N, B, P, R)
MASS P=M, R=M
Q1' = U1
Q2' = U2
GRAVITY(G*N1>)
ZERO = FR() + FRSTAR()
KANE()
INPUT M=1,G=9.81,L=1
INPUT Q1=.1,Q2=.2,U1=0,U2=0
INPUT TFINAL=10, INTEGSTP=.01
CODE DYNAMICS() some_filename.c
PK ]ZZZS���/ / H sympy/parsing/autolev/test-examples/pydy-example-repo/double_pendulum.pyimport sympy.physics.mechanics as _me
import sympy as _sm
import math as m
import numpy as _np
q1, q2, u1, u2 = _me.dynamicsymbols('q1 q2 u1 u2')
q1_d, q2_d, u1_d, u2_d = _me.dynamicsymbols('q1_ q2_ u1_ u2_', 1)
l, m, g = _sm.symbols('l m g', real=True)
frame_n = _me.ReferenceFrame('n')
frame_a = _me.ReferenceFrame('a')
frame_b = _me.ReferenceFrame('b')
frame_a.orient(frame_n, 'Axis', [q1, frame_n.z])
frame_b.orient(frame_n, 'Axis', [q2, frame_n.z])
frame_a.set_ang_vel(frame_n, u1*frame_n.z)
frame_b.set_ang_vel(frame_n, u2*frame_n.z)
point_o = _me.Point('o')
particle_p = _me.Particle('p', _me.Point('p_pt'), _sm.Symbol('m'))
particle_r = _me.Particle('r', _me.Point('r_pt'), _sm.Symbol('m'))
particle_p.point.set_pos(point_o, l*frame_a.x)
particle_r.point.set_pos(particle_p.point, l*frame_b.x)
point_o.set_vel(frame_n, 0)
particle_p.point.v2pt_theory(point_o,frame_n,frame_a)
particle_r.point.v2pt_theory(particle_p.point,frame_n,frame_b)
particle_p.mass = m
particle_r.mass = m
force_p = particle_p.mass*(g*frame_n.x)
force_r = particle_r.mass*(g*frame_n.x)
kd_eqs = [q1_d - u1, q2_d - u2]
forceList = [(particle_p.point,particle_p.mass*(g*frame_n.x)), (particle_r.point,particle_r.mass*(g*frame_n.x))]
kane = _me.KanesMethod(frame_n, q_ind=[q1,q2], u_ind=[u1, u2], kd_eqs = kd_eqs)
fr, frstar = kane.kanes_equations([particle_p, particle_r], forceList)
zero = fr+frstar
from pydy.system import System
sys = System(kane, constants = {l:1, m:1, g:9.81},
specifieds={},
initial_conditions={q1:.1, q2:.2, u1:0, u2:0},
times = _np.linspace(0.0, 10, 10/.01))
y=sys.integrate()
PK ]ZZZM�� � K sympy/parsing/autolev/test-examples/pydy-example-repo/mass_spring_damper.alCONSTANTS M,K,B,G
MOTIONVARIABLES' POSITION',SPEED'
VARIABLES O
FORCE = O*SIN(T)
NEWTONIAN CEILING
POINTS ORIGIN
V_ORIGIN_CEILING> = 0>
PARTICLES BLOCK
P_ORIGIN_BLOCK> = POSITION*CEILING1>
MASS BLOCK=M
V_BLOCK_CEILING>=SPEED*CEILING1>
POSITION' = SPEED
FORCE_MAGNITUDE = M*G-K*POSITION-B*SPEED+FORCE
FORCE_BLOCK>=EXPLICIT(FORCE_MAGNITUDE*CEILING1>)
ZERO = FR() + FRSTAR()
KANE()
INPUT TFINAL=10.0, INTEGSTP=0.01
INPUT M=1.0, K=1.0, B=0.2, G=9.8, POSITION=0.1, SPEED=-1.0, O=2
CODE DYNAMICS() dummy_file.c
PK ]ZZZ����V V K sympy/parsing/autolev/test-examples/pydy-example-repo/mass_spring_damper.pyimport sympy.physics.mechanics as _me
import sympy as _sm
import math as m
import numpy as _np
m, k, b, g = _sm.symbols('m k b g', real=True)
position, speed = _me.dynamicsymbols('position speed')
position_d, speed_d = _me.dynamicsymbols('position_ speed_', 1)
o = _me.dynamicsymbols('o')
force = o*_sm.sin(_me.dynamicsymbols._t)
frame_ceiling = _me.ReferenceFrame('ceiling')
point_origin = _me.Point('origin')
point_origin.set_vel(frame_ceiling, 0)
particle_block = _me.Particle('block', _me.Point('block_pt'), _sm.Symbol('m'))
particle_block.point.set_pos(point_origin, position*frame_ceiling.x)
particle_block.mass = m
particle_block.point.set_vel(frame_ceiling, speed*frame_ceiling.x)
force_magnitude = m*g-k*position-b*speed+force
force_block = (force_magnitude*frame_ceiling.x).subs({position_d:speed})
kd_eqs = [position_d - speed]
forceList = [(particle_block.point,(force_magnitude*frame_ceiling.x).subs({position_d:speed}))]
kane = _me.KanesMethod(frame_ceiling, q_ind=[position], u_ind=[speed], kd_eqs = kd_eqs)
fr, frstar = kane.kanes_equations([particle_block], forceList)
zero = fr+frstar
from pydy.system import System
sys = System(kane, constants = {m:1.0, k:1.0, b:0.2, g:9.8},
specifieds={_me.dynamicsymbols('t'):lambda x, t: t, o:2},
initial_conditions={position:0.1, speed:-1*1.0},
times = _np.linspace(0.0, 10.0, 10.0/0.01))
y=sys.integrate()
PK ]ZZZ4�~�j j I sympy/parsing/autolev/test-examples/pydy-example-repo/non_min_pendulum.alMOTIONVARIABLES' Q{2}''
CONSTANTS L,M,G
NEWTONIAN N
POINT PN
V_PN_N> = 0>
THETA1 = ATAN(Q2/Q1)
FRAMES A
SIMPROT(N, A, 3, THETA1)
PARTICLES P
P_PN_P> = Q1*N1>+Q2*N2>
MASS P=M
V_P_N>=DT(P_P_PN>, N)
F_V = DOT(EXPRESS(V_P_N>,A), A1>)
GRAVITY(G*N1>)
DEPENDENT[1] = F_V
CONSTRAIN(DEPENDENT[Q1'])
ZERO=FR()+FRSTAR()
F_C = MAG(P_P_PN>)-L
CONFIG[1]=F_C
ZERO[2]=CONFIG[1]
PK ]ZZZ�d� � I sympy/parsing/autolev/test-examples/pydy-example-repo/non_min_pendulum.pyimport sympy.physics.mechanics as _me
import sympy as _sm
import math as m
import numpy as _np
q1, q2 = _me.dynamicsymbols('q1 q2')
q1_d, q2_d = _me.dynamicsymbols('q1_ q2_', 1)
q1_dd, q2_dd = _me.dynamicsymbols('q1_ q2_', 2)
l, m, g = _sm.symbols('l m g', real=True)
frame_n = _me.ReferenceFrame('n')
point_pn = _me.Point('pn')
point_pn.set_vel(frame_n, 0)
theta1 = _sm.atan(q2/q1)
frame_a = _me.ReferenceFrame('a')
frame_a.orient(frame_n, 'Axis', [theta1, frame_n.z])
particle_p = _me.Particle('p', _me.Point('p_pt'), _sm.Symbol('m'))
particle_p.point.set_pos(point_pn, q1*frame_n.x+q2*frame_n.y)
particle_p.mass = m
particle_p.point.set_vel(frame_n, (point_pn.pos_from(particle_p.point)).dt(frame_n))
f_v = _me.dot((particle_p.point.vel(frame_n)).express(frame_a), frame_a.x)
force_p = particle_p.mass*(g*frame_n.x)
dependent = _sm.Matrix([[0]])
dependent[0] = f_v
velocity_constraints = [i for i in dependent]
u_q1_d = _me.dynamicsymbols('u_q1_d')
u_q2_d = _me.dynamicsymbols('u_q2_d')
kd_eqs = [q1_d-u_q1_d, q2_d-u_q2_d]
forceList = [(particle_p.point,particle_p.mass*(g*frame_n.x))]
kane = _me.KanesMethod(frame_n, q_ind=[q1,q2], u_ind=[u_q2_d], u_dependent=[u_q1_d], kd_eqs = kd_eqs, velocity_constraints = velocity_constraints)
fr, frstar = kane.kanes_equations([particle_p], forceList)
zero = fr+frstar
f_c = point_pn.pos_from(particle_p.point).magnitude()-l
config = _sm.Matrix([[0]])
config[0] = f_c
zero = zero.row_insert(zero.shape[0], _sm.Matrix([[0]]))
zero[zero.shape[0]-1] = config[0]
PK ]ZZZ � �A A sympy/parsing/c/__init__.py"""Used for translating C source code into a SymPy expression"""
PK ]ZZZ��t#˔ ˔ sympy/parsing/c/c_parser.pyfrom sympy.external import import_module
import os
cin = import_module('clang.cindex', import_kwargs = {'fromlist': ['cindex']})
"""
This module contains all the necessary Classes and Function used to Parse C and
C++ code into SymPy expression
The module serves as a backend for SymPyExpression to parse C code
It is also dependent on Clang's AST and SymPy's Codegen AST.
The module only supports the features currently supported by the Clang and
codegen AST which will be updated as the development of codegen AST and this
module progresses.
You might find unexpected bugs and exceptions while using the module, feel free
to report them to the SymPy Issue Tracker
Features Supported
==================
- Variable Declarations (integers and reals)
- Assignment (using integer & floating literal and function calls)
- Function Definitions and Declaration
- Function Calls
- Compound statements, Return statements
Notes
=====
The module is dependent on an external dependency which needs to be installed
to use the features of this module.
Clang: The C and C++ compiler which is used to extract an AST from the provided
C source code.
References
==========
.. [1] https://github.com/sympy/sympy/issues
.. [2] https://clang.llvm.org/docs/
.. [3] https://clang.llvm.org/docs/IntroductionToTheClangAST.html
"""
if cin:
from sympy.codegen.ast import (Variable, Integer, Float,
FunctionPrototype, FunctionDefinition, FunctionCall,
none, Return, Assignment, intc, int8, int16, int64,
uint8, uint16, uint32, uint64, float32, float64, float80,
aug_assign, bool_, While, CodeBlock)
from sympy.codegen.cnodes import (PreDecrement, PostDecrement,
PreIncrement, PostIncrement)
from sympy.core import Add, Mod, Mul, Pow, Rel
from sympy.logic.boolalg import And, as_Boolean, Not, Or
from sympy.core.symbol import Symbol
from sympy.core.sympify import sympify
from sympy.logic.boolalg import (false, true)
import sys
import tempfile
class BaseParser:
"""Base Class for the C parser"""
def __init__(self):
"""Initializes the Base parser creating a Clang AST index"""
self.index = cin.Index.create()
def diagnostics(self, out):
"""Diagostics function for the Clang AST"""
for diag in self.tu.diagnostics:
# tu = translation unit
print('%s %s (line %s, col %s) %s' % (
{
4: 'FATAL',
3: 'ERROR',
2: 'WARNING',
1: 'NOTE',
0: 'IGNORED',
}[diag.severity],
diag.location.file,
diag.location.line,
diag.location.column,
diag.spelling
), file=out)
class CCodeConverter(BaseParser):
"""The Code Convereter for Clang AST
The converter object takes the C source code or file as input and
converts them to SymPy Expressions.
"""
def __init__(self):
"""Initializes the code converter"""
super().__init__()
self._py_nodes = []
self._data_types = {
"void": {
cin.TypeKind.VOID: none
},
"bool": {
cin.TypeKind.BOOL: bool_
},
"int": {
cin.TypeKind.SCHAR: int8,
cin.TypeKind.SHORT: int16,
cin.TypeKind.INT: intc,
cin.TypeKind.LONG: int64,
cin.TypeKind.UCHAR: uint8,
cin.TypeKind.USHORT: uint16,
cin.TypeKind.UINT: uint32,
cin.TypeKind.ULONG: uint64
},
"float": {
cin.TypeKind.FLOAT: float32,
cin.TypeKind.DOUBLE: float64,
cin.TypeKind.LONGDOUBLE: float80
}
}
def parse(self, filename, flags):
"""Function to parse a file with C source code
It takes the filename as an attribute and creates a Clang AST
Translation Unit parsing the file.
Then the transformation function is called on the translation unit,
whose reults are collected into a list which is returned by the
function.
Parameters
==========
filename : string
Path to the C file to be parsed
flags: list
Arguments to be passed to Clang while parsing the C code
Returns
=======
py_nodes: list
A list of SymPy AST nodes
"""
filepath = os.path.abspath(filename)
self.tu = self.index.parse(
filepath,
args=flags,
options=cin.TranslationUnit.PARSE_DETAILED_PROCESSING_RECORD
)
for child in self.tu.cursor.get_children():
if child.kind == cin.CursorKind.VAR_DECL or child.kind == cin.CursorKind.FUNCTION_DECL:
self._py_nodes.append(self.transform(child))
return self._py_nodes
def parse_str(self, source, flags):
"""Function to parse a string with C source code
It takes the source code as an attribute, stores it in a temporary
file and creates a Clang AST Translation Unit parsing the file.
Then the transformation function is called on the translation unit,
whose reults are collected into a list which is returned by the
function.
Parameters
==========
source : string
A string containing the C source code to be parsed
flags: list
Arguments to be passed to Clang while parsing the C code
Returns
=======
py_nodes: list
A list of SymPy AST nodes
"""
file = tempfile.NamedTemporaryFile(mode = 'w+', suffix = '.cpp')
file.write(source)
file.seek(0)
self.tu = self.index.parse(
file.name,
args=flags,
options=cin.TranslationUnit.PARSE_DETAILED_PROCESSING_RECORD
)
file.close()
for child in self.tu.cursor.get_children():
if child.kind == cin.CursorKind.VAR_DECL or child.kind == cin.CursorKind.FUNCTION_DECL:
self._py_nodes.append(self.transform(child))
return self._py_nodes
def transform(self, node):
"""Transformation Function for Clang AST nodes
It determines the kind of node and calls the respective
transformation function for that node.
Raises
======
NotImplementedError : if the transformation for the provided node
is not implemented
"""
handler = getattr(self, 'transform_%s' % node.kind.name.lower(), None)
if handler is None:
print(
"Ignoring node of type %s (%s)" % (
node.kind,
' '.join(
t.spelling for t in node.get_tokens())
),
file=sys.stderr
)
return handler(node)
def transform_var_decl(self, node):
"""Transformation Function for Variable Declaration
Used to create nodes for variable declarations and assignments with
values or function call for the respective nodes in the clang AST
Returns
=======
A variable node as Declaration, with the initial value if given
Raises
======
NotImplementedError : if called for data types not currently
implemented
Notes
=====
The function currently supports following data types:
Boolean:
bool, _Bool
Integer:
8-bit: signed char and unsigned char
16-bit: short, short int, signed short,
signed short int, unsigned short, unsigned short int
32-bit: int, signed int, unsigned int
64-bit: long, long int, signed long,
signed long int, unsigned long, unsigned long int
Floating point:
Single Precision: float
Double Precision: double
Extended Precision: long double
"""
if node.type.kind in self._data_types["int"]:
type = self._data_types["int"][node.type.kind]
elif node.type.kind in self._data_types["float"]:
type = self._data_types["float"][node.type.kind]
elif node.type.kind in self._data_types["bool"]:
type = self._data_types["bool"][node.type.kind]
else:
raise NotImplementedError("Only bool, int "
"and float are supported")
try:
children = node.get_children()
child = next(children)
#ignoring namespace and type details for the variable
while child.kind == cin.CursorKind.NAMESPACE_REF or child.kind == cin.CursorKind.TYPE_REF:
child = next(children)
val = self.transform(child)
supported_rhs = [
cin.CursorKind.INTEGER_LITERAL,
cin.CursorKind.FLOATING_LITERAL,
cin.CursorKind.UNEXPOSED_EXPR,
cin.CursorKind.BINARY_OPERATOR,
cin.CursorKind.PAREN_EXPR,
cin.CursorKind.UNARY_OPERATOR,
cin.CursorKind.CXX_BOOL_LITERAL_EXPR
]
if child.kind in supported_rhs:
if isinstance(val, str):
value = Symbol(val)
elif isinstance(val, bool):
if node.type.kind in self._data_types["int"]:
value = Integer(0) if val == False else Integer(1)
elif node.type.kind in self._data_types["float"]:
value = Float(0.0) if val == False else Float(1.0)
elif node.type.kind in self._data_types["bool"]:
value = sympify(val)
elif isinstance(val, (Integer, int, Float, float)):
if node.type.kind in self._data_types["int"]:
value = Integer(val)
elif node.type.kind in self._data_types["float"]:
value = Float(val)
elif node.type.kind in self._data_types["bool"]:
value = sympify(bool(val))
else:
value = val
return Variable(
node.spelling
).as_Declaration(
type = type,
value = value
)
elif child.kind == cin.CursorKind.CALL_EXPR:
return Variable(
node.spelling
).as_Declaration(
value = val
)
else:
raise NotImplementedError("Given "
"variable declaration \"{}\" "
"is not possible to parse yet!"
.format(" ".join(
t.spelling for t in node.get_tokens()
)
))
except StopIteration:
return Variable(
node.spelling
).as_Declaration(
type = type
)
def transform_function_decl(self, node):
"""Transformation Function For Function Declaration
Used to create nodes for function declarations and definitions for
the respective nodes in the clang AST
Returns
=======
function : Codegen AST node
- FunctionPrototype node if function body is not present
- FunctionDefinition node if the function body is present
"""
if node.result_type.kind in self._data_types["int"]:
ret_type = self._data_types["int"][node.result_type.kind]
elif node.result_type.kind in self._data_types["float"]:
ret_type = self._data_types["float"][node.result_type.kind]
elif node.result_type.kind in self._data_types["bool"]:
ret_type = self._data_types["bool"][node.result_type.kind]
elif node.result_type.kind in self._data_types["void"]:
ret_type = self._data_types["void"][node.result_type.kind]
else:
raise NotImplementedError("Only void, bool, int "
"and float are supported")
body = []
param = []
# Subsequent nodes will be the parameters for the function.
for child in node.get_children():
decl = self.transform(child)
if child.kind == cin.CursorKind.PARM_DECL:
param.append(decl)
elif child.kind == cin.CursorKind.COMPOUND_STMT:
for val in decl:
body.append(val)
else:
body.append(decl)
if body == []:
function = FunctionPrototype(
return_type = ret_type,
name = node.spelling,
parameters = param
)
else:
function = FunctionDefinition(
return_type = ret_type,
name = node.spelling,
parameters = param,
body = body
)
return function
def transform_parm_decl(self, node):
"""Transformation function for Parameter Declaration
Used to create parameter nodes for the required functions for the
respective nodes in the clang AST
Returns
=======
param : Codegen AST Node
Variable node with the value and type of the variable
Raises
======
ValueError if multiple children encountered in the parameter node
"""
if node.type.kind in self._data_types["int"]:
type = self._data_types["int"][node.type.kind]
elif node.type.kind in self._data_types["float"]:
type = self._data_types["float"][node.type.kind]
elif node.type.kind in self._data_types["bool"]:
type = self._data_types["bool"][node.type.kind]
else:
raise NotImplementedError("Only bool, int "
"and float are supported")
try:
children = node.get_children()
child = next(children)
# Any namespace nodes can be ignored
while child.kind in [cin.CursorKind.NAMESPACE_REF,
cin.CursorKind.TYPE_REF,
cin.CursorKind.TEMPLATE_REF]:
child = next(children)
# If there is a child, it is the default value of the parameter.
lit = self.transform(child)
if node.type.kind in self._data_types["int"]:
val = Integer(lit)
elif node.type.kind in self._data_types["float"]:
val = Float(lit)
elif node.type.kind in self._data_types["bool"]:
val = sympify(bool(lit))
else:
raise NotImplementedError("Only bool, int "
"and float are supported")
param = Variable(
node.spelling
).as_Declaration(
type = type,
value = val
)
except StopIteration:
param = Variable(
node.spelling
).as_Declaration(
type = type
)
try:
self.transform(next(children))
raise ValueError("Can't handle multiple children on parameter")
except StopIteration:
pass
return param
def transform_integer_literal(self, node):
"""Transformation function for integer literal
Used to get the value and type of the given integer literal.
Returns
=======
val : list
List with two arguments type and Value
type contains the type of the integer
value contains the value stored in the variable
Notes
=====
Only Base Integer type supported for now
"""
try:
value = next(node.get_tokens()).spelling
except StopIteration:
# No tokens
value = node.literal
return int(value)
def transform_floating_literal(self, node):
"""Transformation function for floating literal
Used to get the value and type of the given floating literal.
Returns
=======
val : list
List with two arguments type and Value
type contains the type of float
value contains the value stored in the variable
Notes
=====
Only Base Float type supported for now
"""
try:
value = next(node.get_tokens()).spelling
except (StopIteration, ValueError):
# No tokens
value = node.literal
return float(value)
def transform_string_literal(self, node):
#TODO: No string type in AST
#type =
#try:
# value = next(node.get_tokens()).spelling
#except (StopIteration, ValueError):
# No tokens
# value = node.literal
#val = [type, value]
#return val
pass
def transform_character_literal(self, node):
"""Transformation function for character literal
Used to get the value of the given character literal.
Returns
=======
val : int
val contains the ascii value of the character literal
Notes
=====
Only for cases where character is assigned to a integer value,
since character literal is not in SymPy AST
"""
try:
value = next(node.get_tokens()).spelling
except (StopIteration, ValueError):
# No tokens
value = node.literal
return ord(str(value[1]))
def transform_cxx_bool_literal_expr(self, node):
"""Transformation function for boolean literal
Used to get the value of the given boolean literal.
Returns
=======
value : bool
value contains the boolean value of the variable
"""
try:
value = next(node.get_tokens()).spelling
except (StopIteration, ValueError):
value = node.literal
return True if value == 'true' else False
def transform_unexposed_decl(self,node):
"""Transformation function for unexposed declarations"""
pass
def transform_unexposed_expr(self, node):
"""Transformation function for unexposed expression
Unexposed expressions are used to wrap float, double literals and
expressions
Returns
=======
expr : Codegen AST Node
the result from the wrapped expression
None : NoneType
No childs are found for the node
Raises
======
ValueError if the expression contains multiple children
"""
# Ignore unexposed nodes; pass whatever is the first
# (and should be only) child unaltered.
try:
children = node.get_children()
expr = self.transform(next(children))
except StopIteration:
return None
try:
next(children)
raise ValueError("Unexposed expression has > 1 children.")
except StopIteration:
pass
return expr
def transform_decl_ref_expr(self, node):
"""Returns the name of the declaration reference"""
return node.spelling
def transform_call_expr(self, node):
"""Transformation function for a call expression
Used to create function call nodes for the function calls present
in the C code
Returns
=======
FunctionCall : Codegen AST Node
FunctionCall node with parameters if any parameters are present
"""
param = []
children = node.get_children()
child = next(children)
while child.kind == cin.CursorKind.NAMESPACE_REF:
child = next(children)
while child.kind == cin.CursorKind.TYPE_REF:
child = next(children)
first_child = self.transform(child)
try:
for child in children:
arg = self.transform(child)
if child.kind == cin.CursorKind.INTEGER_LITERAL:
param.append(Integer(arg))
elif child.kind == cin.CursorKind.FLOATING_LITERAL:
param.append(Float(arg))
else:
param.append(arg)
return FunctionCall(first_child, param)
except StopIteration:
return FunctionCall(first_child)
def transform_return_stmt(self, node):
"""Returns the Return Node for a return statement"""
return Return(next(node.get_children()).spelling)
def transform_compound_stmt(self, node):
"""Transformation function for compond statemets
Returns
=======
expr : list
list of Nodes for the expressions present in the statement
None : NoneType
if the compound statement is empty
"""
expr = []
children = node.get_children()
for child in children:
expr.append(self.transform(child))
return expr
def transform_decl_stmt(self, node):
"""Transformation function for declaration statements
These statements are used to wrap different kinds of declararions
like variable or function declaration
The function calls the transformer function for the child of the
given node
Returns
=======
statement : Codegen AST Node
contains the node returned by the children node for the type of
declaration
Raises
======
ValueError if multiple children present
"""
try:
children = node.get_children()
statement = self.transform(next(children))
except StopIteration:
pass
try:
self.transform(next(children))
raise ValueError("Don't know how to handle multiple statements")
except StopIteration:
pass
return statement
def transform_paren_expr(self, node):
"""Transformation function for Parenthesized expressions
Returns the result from its children nodes
"""
return self.transform(next(node.get_children()))
def transform_compound_assignment_operator(self, node):
"""Transformation function for handling shorthand operators
Returns
=======
augmented_assignment_expression: Codegen AST node
shorthand assignment expression represented as Codegen AST
Raises
======
NotImplementedError
If the shorthand operator for bitwise operators
(~=, ^=, &=, |=, <<=, >>=) is encountered
"""
return self.transform_binary_operator(node)
def transform_unary_operator(self, node):
"""Transformation function for handling unary operators
Returns
=======
unary_expression: Codegen AST node
simplified unary expression represented as Codegen AST
Raises
======
NotImplementedError
If dereferencing operator(*), address operator(&) or
bitwise NOT operator(~) is encountered
"""
# supported operators list
operators_list = ['+', '-', '++', '--', '!']
tokens = list(node.get_tokens())
# it can be either pre increment/decrement or any other operator from the list
if tokens[0].spelling in operators_list:
child = self.transform(next(node.get_children()))
# (decl_ref) e.g.; int a = ++b; or simply ++b;
if isinstance(child, str):
if tokens[0].spelling == '+':
return Symbol(child)
if tokens[0].spelling == '-':
return Mul(Symbol(child), -1)
if tokens[0].spelling == '++':
return PreIncrement(Symbol(child))
if tokens[0].spelling == '--':
return PreDecrement(Symbol(child))
if tokens[0].spelling == '!':
return Not(Symbol(child))
# e.g.; int a = -1; or int b = -(1 + 2);
else:
if tokens[0].spelling == '+':
return child
if tokens[0].spelling == '-':
return Mul(child, -1)
if tokens[0].spelling == '!':
return Not(sympify(bool(child)))
# it can be either post increment/decrement
# since variable name is obtained in token[0].spelling
elif tokens[1].spelling in ['++', '--']:
child = self.transform(next(node.get_children()))
if tokens[1].spelling == '++':
return PostIncrement(Symbol(child))
if tokens[1].spelling == '--':
return PostDecrement(Symbol(child))
else:
raise NotImplementedError("Dereferencing operator, "
"Address operator and bitwise NOT operator "
"have not been implemented yet!")
def transform_binary_operator(self, node):
"""Transformation function for handling binary operators
Returns
=======
binary_expression: Codegen AST node
simplified binary expression represented as Codegen AST
Raises
======
NotImplementedError
If a bitwise operator or
unary operator(which is a child of any binary
operator in Clang AST) is encountered
"""
# get all the tokens of assignment
# and store it in the tokens list
tokens = list(node.get_tokens())
# supported operators list
operators_list = ['+', '-', '*', '/', '%','=',
'>', '>=', '<', '<=', '==', '!=', '&&', '||', '+=', '-=',
'*=', '/=', '%=']
# this stack will contain variable content
# and type of variable in the rhs
combined_variables_stack = []
# this stack will contain operators
# to be processed in the rhs
operators_stack = []
# iterate through every token
for token in tokens:
# token is either '(', ')' or
# any of the supported operators from the operator list
if token.kind == cin.TokenKind.PUNCTUATION:
# push '(' to the operators stack
if token.spelling == '(':
operators_stack.append('(')
elif token.spelling == ')':
# keep adding the expression to the
# combined variables stack unless
# '(' is found
while (operators_stack
and operators_stack[-1] != '('):
if len(combined_variables_stack) < 2:
raise NotImplementedError(
"Unary operators as a part of "
"binary operators is not "
"supported yet!")
rhs = combined_variables_stack.pop()
lhs = combined_variables_stack.pop()
operator = operators_stack.pop()
combined_variables_stack.append(
self.perform_operation(
lhs, rhs, operator))
# pop '('
operators_stack.pop()
# token is an operator (supported)
elif token.spelling in operators_list:
while (operators_stack
and self.priority_of(token.spelling)
<= self.priority_of(
operators_stack[-1])):
if len(combined_variables_stack) < 2:
raise NotImplementedError(
"Unary operators as a part of "
"binary operators is not "
"supported yet!")
rhs = combined_variables_stack.pop()
lhs = combined_variables_stack.pop()
operator = operators_stack.pop()
combined_variables_stack.append(
self.perform_operation(
lhs, rhs, operator))
# push current operator
operators_stack.append(token.spelling)
# token is a bitwise operator
elif token.spelling in ['&', '|', '^', '<<', '>>']:
raise NotImplementedError(
"Bitwise operator has not been "
"implemented yet!")
# token is a shorthand bitwise operator
elif token.spelling in ['&=', '|=', '^=', '<<=',
'>>=']:
raise NotImplementedError(
"Shorthand bitwise operator has not been "
"implemented yet!")
else:
raise NotImplementedError(
"Given token {} is not implemented yet!"
.format(token.spelling))
# token is an identifier(variable)
elif token.kind == cin.TokenKind.IDENTIFIER:
combined_variables_stack.append(
[token.spelling, 'identifier'])
# token is a literal
elif token.kind == cin.TokenKind.LITERAL:
combined_variables_stack.append(
[token.spelling, 'literal'])
# token is a keyword, either true or false
elif (token.kind == cin.TokenKind.KEYWORD
and token.spelling in ['true', 'false']):
combined_variables_stack.append(
[token.spelling, 'boolean'])
else:
raise NotImplementedError(
"Given token {} is not implemented yet!"
.format(token.spelling))
# process remaining operators
while operators_stack:
if len(combined_variables_stack) < 2:
raise NotImplementedError(
"Unary operators as a part of "
"binary operators is not "
"supported yet!")
rhs = combined_variables_stack.pop()
lhs = combined_variables_stack.pop()
operator = operators_stack.pop()
combined_variables_stack.append(
self.perform_operation(lhs, rhs, operator))
return combined_variables_stack[-1][0]
def priority_of(self, op):
"""To get the priority of given operator"""
if op in ['=', '+=', '-=', '*=', '/=', '%=']:
return 1
if op in ['&&', '||']:
return 2
if op in ['<', '<=', '>', '>=', '==', '!=']:
return 3
if op in ['+', '-']:
return 4
if op in ['*', '/', '%']:
return 5
return 0
def perform_operation(self, lhs, rhs, op):
"""Performs operation supported by the SymPy core
Returns
=======
combined_variable: list
contains variable content and type of variable
"""
lhs_value = self.get_expr_for_operand(lhs)
rhs_value = self.get_expr_for_operand(rhs)
if op == '+':
return [Add(lhs_value, rhs_value), 'expr']
if op == '-':
return [Add(lhs_value, -rhs_value), 'expr']
if op == '*':
return [Mul(lhs_value, rhs_value), 'expr']
if op == '/':
return [Mul(lhs_value, Pow(rhs_value, Integer(-1))), 'expr']
if op == '%':
return [Mod(lhs_value, rhs_value), 'expr']
if op in ['<', '<=', '>', '>=', '==', '!=']:
return [Rel(lhs_value, rhs_value, op), 'expr']
if op == '&&':
return [And(as_Boolean(lhs_value), as_Boolean(rhs_value)), 'expr']
if op == '||':
return [Or(as_Boolean(lhs_value), as_Boolean(rhs_value)), 'expr']
if op == '=':
return [Assignment(Variable(lhs_value), rhs_value), 'expr']
if op in ['+=', '-=', '*=', '/=', '%=']:
return [aug_assign(Variable(lhs_value), op[0], rhs_value), 'expr']
def get_expr_for_operand(self, combined_variable):
"""Gives out SymPy Codegen AST node
AST node returned is corresponding to
combined variable passed.Combined variable contains
variable content and type of variable
"""
if combined_variable[1] == 'identifier':
return Symbol(combined_variable[0])
if combined_variable[1] == 'literal':
if '.' in combined_variable[0]:
return Float(float(combined_variable[0]))
else:
return Integer(int(combined_variable[0]))
if combined_variable[1] == 'expr':
return combined_variable[0]
if combined_variable[1] == 'boolean':
return true if combined_variable[0] == 'true' else false
def transform_null_stmt(self, node):
"""Handles Null Statement and returns None"""
return none
def transform_while_stmt(self, node):
"""Transformation function for handling while statement
Returns
=======
while statement : Codegen AST Node
contains the while statement node having condition and
statement block
"""
children = node.get_children()
condition = self.transform(next(children))
statements = self.transform(next(children))
if isinstance(statements, list):
statement_block = CodeBlock(*statements)
else:
statement_block = CodeBlock(statements)
return While(condition, statement_block)
else:
class CCodeConverter(): # type: ignore
def __init__(self, *args, **kwargs):
raise ImportError("Module not Installed")
def parse_c(source):
"""Function for converting a C source code
The function reads the source code present in the given file and parses it
to give out SymPy Expressions
Returns
=======
src : list
List of Python expression strings
"""
converter = CCodeConverter()
if os.path.exists(source):
src = converter.parse(source, flags = [])
else:
src = converter.parse_str(source, flags = [])
return src
PK ]ZZZ�}�I I ! sympy/parsing/fortran/__init__.py"""Used for translating Fortran source code into a SymPy expression. """
PK ]ZZZ{x��, �, ' sympy/parsing/fortran/fortran_parser.pyfrom sympy.external import import_module
lfortran = import_module('lfortran')
if lfortran:
from sympy.codegen.ast import (Variable, IntBaseType, FloatBaseType, String,
Return, FunctionDefinition, Assignment)
from sympy.core import Add, Mul, Integer, Float
from sympy.core.symbol import Symbol
asr_mod = lfortran.asr
asr = lfortran.asr.asr
src_to_ast = lfortran.ast.src_to_ast
ast_to_asr = lfortran.semantic.ast_to_asr.ast_to_asr
"""
This module contains all the necessary Classes and Function used to Parse
Fortran code into SymPy expression
The module and its API are currently under development and experimental.
It is also dependent on LFortran for the ASR that is converted to SymPy syntax
which is also under development.
The module only supports the features currently supported by the LFortran ASR
which will be updated as the development of LFortran and this module progresses
You might find unexpected bugs and exceptions while using the module, feel free
to report them to the SymPy Issue Tracker
The API for the module might also change while in development if better and
more effective ways are discovered for the process
Features Supported
==================
- Variable Declarations (integers and reals)
- Function Definitions
- Assignments and Basic Binary Operations
Notes
=====
The module depends on an external dependency
LFortran : Required to parse Fortran source code into ASR
References
==========
.. [1] https://github.com/sympy/sympy/issues
.. [2] https://gitlab.com/lfortran/lfortran
.. [3] https://docs.lfortran.org/
"""
class ASR2PyVisitor(asr.ASTVisitor): # type: ignore
"""
Visitor Class for LFortran ASR
It is a Visitor class derived from asr.ASRVisitor which visits all the
nodes of the LFortran ASR and creates corresponding AST node for each
ASR node
"""
def __init__(self):
"""Initialize the Parser"""
self._py_ast = []
def visit_TranslationUnit(self, node):
"""
Function to visit all the elements of the Translation Unit
created by LFortran ASR
"""
for s in node.global_scope.symbols:
sym = node.global_scope.symbols[s]
self.visit(sym)
for item in node.items:
self.visit(item)
def visit_Assignment(self, node):
"""Visitor Function for Assignment
Visits each Assignment is the LFortran ASR and creates corresponding
assignment for SymPy.
Notes
=====
The function currently only supports variable assignment and binary
operation assignments of varying multitudes. Any type of numberS or
array is not supported.
Raises
======
NotImplementedError() when called for Numeric assignments or Arrays
"""
# TODO: Arithmetic Assignment
if isinstance(node.target, asr.Variable):
target = node.target
value = node.value
if isinstance(value, asr.Variable):
new_node = Assignment(
Variable(
target.name
),
Variable(
value.name
)
)
elif (type(value) == asr.BinOp):
exp_ast = call_visitor(value)
for expr in exp_ast:
new_node = Assignment(
Variable(target.name),
expr
)
else:
raise NotImplementedError("Numeric assignments not supported")
else:
raise NotImplementedError("Arrays not supported")
self._py_ast.append(new_node)
def visit_BinOp(self, node):
"""Visitor Function for Binary Operations
Visits each binary operation present in the LFortran ASR like addition,
subtraction, multiplication, division and creates the corresponding
operation node in SymPy's AST
In case of more than one binary operations, the function calls the
call_visitor() function on the child nodes of the binary operations
recursively until all the operations have been processed.
Notes
=====
The function currently only supports binary operations with Variables
or other binary operations. Numerics are not supported as of yet.
Raises
======
NotImplementedError() when called for Numeric assignments
"""
# TODO: Integer Binary Operations
op = node.op
lhs = node.left
rhs = node.right
if (type(lhs) == asr.Variable):
left_value = Symbol(lhs.name)
elif(type(lhs) == asr.BinOp):
l_exp_ast = call_visitor(lhs)
for exp in l_exp_ast:
left_value = exp
else:
raise NotImplementedError("Numbers Currently not supported")
if (type(rhs) == asr.Variable):
right_value = Symbol(rhs.name)
elif(type(rhs) == asr.BinOp):
r_exp_ast = call_visitor(rhs)
for exp in r_exp_ast:
right_value = exp
else:
raise NotImplementedError("Numbers Currently not supported")
if isinstance(op, asr.Add):
new_node = Add(left_value, right_value)
elif isinstance(op, asr.Sub):
new_node = Add(left_value, -right_value)
elif isinstance(op, asr.Div):
new_node = Mul(left_value, 1/right_value)
elif isinstance(op, asr.Mul):
new_node = Mul(left_value, right_value)
self._py_ast.append(new_node)
def visit_Variable(self, node):
"""Visitor Function for Variable Declaration
Visits each variable declaration present in the ASR and creates a
Symbol declaration for each variable
Notes
=====
The functions currently only support declaration of integer and
real variables. Other data types are still under development.
Raises
======
NotImplementedError() when called for unsupported data types
"""
if isinstance(node.type, asr.Integer):
var_type = IntBaseType(String('integer'))
value = Integer(0)
elif isinstance(node.type, asr.Real):
var_type = FloatBaseType(String('real'))
value = Float(0.0)
else:
raise NotImplementedError("Data type not supported")
if not (node.intent == 'in'):
new_node = Variable(
node.name
).as_Declaration(
type = var_type,
value = value
)
self._py_ast.append(new_node)
def visit_Sequence(self, seq):
"""Visitor Function for code sequence
Visits a code sequence/ block and calls the visitor function on all the
children of the code block to create corresponding code in python
"""
if seq is not None:
for node in seq:
self._py_ast.append(call_visitor(node))
def visit_Num(self, node):
"""Visitor Function for Numbers in ASR
This function is currently under development and will be updated
with improvements in the LFortran ASR
"""
# TODO:Numbers when the LFortran ASR is updated
# self._py_ast.append(Integer(node.n))
pass
def visit_Function(self, node):
"""Visitor Function for function Definitions
Visits each function definition present in the ASR and creates a
function definition node in the Python AST with all the elements of the
given function
The functions declare all the variables required as SymPy symbols in
the function before the function definition
This function also the call_visior_function to parse the contents of
the function body
"""
# TODO: Return statement, variable declaration
fn_args = [Variable(arg_iter.name) for arg_iter in node.args]
fn_body = []
fn_name = node.name
for i in node.body:
fn_ast = call_visitor(i)
try:
fn_body_expr = fn_ast
except UnboundLocalError:
fn_body_expr = []
for sym in node.symtab.symbols:
decl = call_visitor(node.symtab.symbols[sym])
for symbols in decl:
fn_body.append(symbols)
for elem in fn_body_expr:
fn_body.append(elem)
fn_body.append(
Return(
Variable(
node.return_var.name
)
)
)
if isinstance(node.return_var.type, asr.Integer):
ret_type = IntBaseType(String('integer'))
elif isinstance(node.return_var.type, asr.Real):
ret_type = FloatBaseType(String('real'))
else:
raise NotImplementedError("Data type not supported")
new_node = FunctionDefinition(
return_type = ret_type,
name = fn_name,
parameters = fn_args,
body = fn_body
)
self._py_ast.append(new_node)
def ret_ast(self):
"""Returns the AST nodes"""
return self._py_ast
else:
class ASR2PyVisitor(): # type: ignore
def __init__(self, *args, **kwargs):
raise ImportError('lfortran not available')
def call_visitor(fort_node):
"""Calls the AST Visitor on the Module
This function is used to call the AST visitor for a program or module
It imports all the required modules and calls the visit() function
on the given node
Parameters
==========
fort_node : LFortran ASR object
Node for the operation for which the NodeVisitor is called
Returns
=======
res_ast : list
list of SymPy AST Nodes
"""
v = ASR2PyVisitor()
v.visit(fort_node)
res_ast = v.ret_ast()
return res_ast
def src_to_sympy(src):
"""Wrapper function to convert the given Fortran source code to SymPy Expressions
Parameters
==========
src : string
A string with the Fortran source code
Returns
=======
py_src : string
A string with the Python source code compatible with SymPy
"""
a_ast = src_to_ast(src, translation_unit=False)
a = ast_to_asr(a_ast)
py_src = call_visitor(a)
return py_src
PK ]ZZZ�X3 3 sympy/parsing/latex/LICENSE.txtThe MIT License (MIT)
Copyright 2016, latex2sympy
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
PK ]ZZZ��K� � sympy/parsing/latex/LaTeX.g4/*
ANTLR4 LaTeX Math Grammar
Ported from latex2sympy by @augustt198 https://github.com/augustt198/latex2sympy See license in
LICENSE.txt
*/
/*
After changing this file, it is necessary to run `python setup.py antlr` in the root directory of
the repository. This will regenerate the code in `sympy/parsing/latex/_antlr/*.py`.
*/
grammar LaTeX;
options {
language = Python3;
}
WS: [ \t\r\n]+ -> skip;
THINSPACE: ('\\,' | '\\thinspace') -> skip;
MEDSPACE: ('\\:' | '\\medspace') -> skip;
THICKSPACE: ('\\;' | '\\thickspace') -> skip;
QUAD: '\\quad' -> skip;
QQUAD: '\\qquad' -> skip;
NEGTHINSPACE: ('\\!' | '\\negthinspace') -> skip;
NEGMEDSPACE: '\\negmedspace' -> skip;
NEGTHICKSPACE: '\\negthickspace' -> skip;
CMD_LEFT: '\\left' -> skip;
CMD_RIGHT: '\\right' -> skip;
IGNORE:
(
'\\vrule'
| '\\vcenter'
| '\\vbox'
| '\\vskip'
| '\\vspace'
| '\\hfil'
| '\\*'
| '\\-'
| '\\.'
| '\\/'
| '\\"'
| '\\('
| '\\='
) -> skip;
ADD: '+';
SUB: '-';
MUL: '*';
DIV: '/';
L_PAREN: '(';
R_PAREN: ')';
L_BRACE: '{';
R_BRACE: '}';
L_BRACE_LITERAL: '\\{';
R_BRACE_LITERAL: '\\}';
L_BRACKET: '[';
R_BRACKET: ']';
BAR: '|';
R_BAR: '\\right|';
L_BAR: '\\left|';
L_ANGLE: '\\langle';
R_ANGLE: '\\rangle';
FUNC_LIM: '\\lim';
LIM_APPROACH_SYM:
'\\to'
| '\\rightarrow'
| '\\Rightarrow'
| '\\longrightarrow'
| '\\Longrightarrow';
FUNC_INT:
'\\int'
| '\\int\\limits';
FUNC_SUM: '\\sum';
FUNC_PROD: '\\prod';
FUNC_EXP: '\\exp';
FUNC_LOG: '\\log';
FUNC_LG: '\\lg';
FUNC_LN: '\\ln';
FUNC_SIN: '\\sin';
FUNC_COS: '\\cos';
FUNC_TAN: '\\tan';
FUNC_CSC: '\\csc';
FUNC_SEC: '\\sec';
FUNC_COT: '\\cot';
FUNC_ARCSIN: '\\arcsin';
FUNC_ARCCOS: '\\arccos';
FUNC_ARCTAN: '\\arctan';
FUNC_ARCCSC: '\\arccsc';
FUNC_ARCSEC: '\\arcsec';
FUNC_ARCCOT: '\\arccot';
FUNC_SINH: '\\sinh';
FUNC_COSH: '\\cosh';
FUNC_TANH: '\\tanh';
FUNC_ARSINH: '\\arsinh';
FUNC_ARCOSH: '\\arcosh';
FUNC_ARTANH: '\\artanh';
L_FLOOR: '\\lfloor';
R_FLOOR: '\\rfloor';
L_CEIL: '\\lceil';
R_CEIL: '\\rceil';
FUNC_SQRT: '\\sqrt';
FUNC_OVERLINE: '\\overline';
CMD_TIMES: '\\times';
CMD_CDOT: '\\cdot';
CMD_DIV: '\\div';
CMD_FRAC:
'\\frac'
| '\\dfrac'
| '\\tfrac';
CMD_BINOM: '\\binom';
CMD_DBINOM: '\\dbinom';
CMD_TBINOM: '\\tbinom';
CMD_MATHIT: '\\mathit';
UNDERSCORE: '_';
CARET: '^';
COLON: ':';
fragment WS_CHAR: [ \t\r\n];
DIFFERENTIAL: 'd' WS_CHAR*? ([a-zA-Z] | '\\' [a-zA-Z]+);
LETTER: [a-zA-Z];
DIGIT: [0-9];
EQUAL: (('&' WS_CHAR*?)? '=') | ('=' (WS_CHAR*? '&')?);
NEQ: '\\neq';
LT: '<';
LTE: ('\\leq' | '\\le' | LTE_Q | LTE_S);
LTE_Q: '\\leqq';
LTE_S: '\\leqslant';
GT: '>';
GTE: ('\\geq' | '\\ge' | GTE_Q | GTE_S);
GTE_Q: '\\geqq';
GTE_S: '\\geqslant';
BANG: '!';
SINGLE_QUOTES: '\''+;
SYMBOL: '\\' [a-zA-Z]+;
math: relation;
relation:
relation (EQUAL | LT | LTE | GT | GTE | NEQ) relation
| expr;
equality: expr EQUAL expr;
expr: additive;
additive: additive (ADD | SUB) additive | mp;
// mult part
mp:
mp (MUL | CMD_TIMES | CMD_CDOT | DIV | CMD_DIV | COLON) mp
| unary;
mp_nofunc:
mp_nofunc (
MUL
| CMD_TIMES
| CMD_CDOT
| DIV
| CMD_DIV
| COLON
) mp_nofunc
| unary_nofunc;
unary: (ADD | SUB) unary | postfix+;
unary_nofunc:
(ADD | SUB) unary_nofunc
| postfix postfix_nofunc*;
postfix: exp postfix_op*;
postfix_nofunc: exp_nofunc postfix_op*;
postfix_op: BANG | eval_at;
eval_at:
BAR (eval_at_sup | eval_at_sub | eval_at_sup eval_at_sub);
eval_at_sub: UNDERSCORE L_BRACE (expr | equality) R_BRACE;
eval_at_sup: CARET L_BRACE (expr | equality) R_BRACE;
exp: exp CARET (atom | L_BRACE expr R_BRACE) subexpr? | comp;
exp_nofunc:
exp_nofunc CARET (atom | L_BRACE expr R_BRACE) subexpr?
| comp_nofunc;
comp:
group
| abs_group
| func
| atom
| floor
| ceil;
comp_nofunc:
group
| abs_group
| atom
| floor
| ceil;
group:
L_PAREN expr R_PAREN
| L_BRACKET expr R_BRACKET
| L_BRACE expr R_BRACE
| L_BRACE_LITERAL expr R_BRACE_LITERAL;
abs_group: BAR expr BAR;
number: DIGIT+ (',' DIGIT DIGIT DIGIT)* ('.' DIGIT+)?;
atom: (LETTER | SYMBOL) (subexpr? SINGLE_QUOTES? | SINGLE_QUOTES? subexpr?)
| number
| DIFFERENTIAL
| mathit
| frac
| binom
| bra
| ket;
bra: L_ANGLE expr (R_BAR | BAR);
ket: (L_BAR | BAR) expr R_ANGLE;
mathit: CMD_MATHIT L_BRACE mathit_text R_BRACE;
mathit_text: LETTER*;
frac: CMD_FRAC (upperd = DIGIT | L_BRACE upper = expr R_BRACE)
(lowerd = DIGIT | L_BRACE lower = expr R_BRACE);
binom:
(CMD_BINOM | CMD_DBINOM | CMD_TBINOM) L_BRACE n = expr R_BRACE L_BRACE k = expr R_BRACE;
floor: L_FLOOR val = expr R_FLOOR;
ceil: L_CEIL val = expr R_CEIL;
func_normal:
FUNC_EXP
| FUNC_LOG
| FUNC_LG
| FUNC_LN
| FUNC_SIN
| FUNC_COS
| FUNC_TAN
| FUNC_CSC
| FUNC_SEC
| FUNC_COT
| FUNC_ARCSIN
| FUNC_ARCCOS
| FUNC_ARCTAN
| FUNC_ARCCSC
| FUNC_ARCSEC
| FUNC_ARCCOT
| FUNC_SINH
| FUNC_COSH
| FUNC_TANH
| FUNC_ARSINH
| FUNC_ARCOSH
| FUNC_ARTANH;
func:
func_normal (subexpr? supexpr? | supexpr? subexpr?) (
L_PAREN func_arg R_PAREN
| func_arg_noparens
)
| (LETTER | SYMBOL) (subexpr? SINGLE_QUOTES? | SINGLE_QUOTES? subexpr?) // e.g. f(x), f_1'(x)
L_PAREN args R_PAREN
| FUNC_INT (subexpr supexpr | supexpr subexpr)? (
additive? DIFFERENTIAL
| frac
| additive
)
| FUNC_SQRT (L_BRACKET root = expr R_BRACKET)? L_BRACE base = expr R_BRACE
| FUNC_OVERLINE L_BRACE base = expr R_BRACE
| (FUNC_SUM | FUNC_PROD) (subeq supexpr | supexpr subeq) mp
| FUNC_LIM limit_sub mp;
args: (expr ',' args) | expr;
limit_sub:
UNDERSCORE L_BRACE (LETTER | SYMBOL) LIM_APPROACH_SYM expr (
CARET ((L_BRACE (ADD | SUB) R_BRACE) | ADD | SUB)
)? R_BRACE;
func_arg: expr | (expr ',' func_arg);
func_arg_noparens: mp_nofunc;
subexpr: UNDERSCORE (atom | L_BRACE expr R_BRACE);
supexpr: CARET (atom | L_BRACE expr R_BRACE);
subeq: UNDERSCORE L_BRACE equality R_BRACE;
supeq: UNDERSCORE L_BRACE equality R_BRACE;
PK ]ZZZ��A�� � sympy/parsing/latex/__init__.pyfrom sympy.external import import_module
from sympy.utilities.decorator import doctest_depends_on
from sympy.parsing.latex.lark import LarkLaTeXParser, TransformToSymPyExpr, parse_latex_lark # noqa
from .errors import LaTeXParsingError # noqa
__doctest_requires__ = {('parse_latex',): ['antlr4', 'lark']}
@doctest_depends_on(modules=('antlr4', 'lark'))
def parse_latex(s, strict=False, backend="antlr"):
r"""Converts the input LaTeX string ``s`` to a SymPy ``Expr``.
Parameters
==========
s : str
The LaTeX string to parse. In Python source containing LaTeX,
*raw strings* (denoted with ``r"``, like this one) are preferred,
as LaTeX makes liberal use of the ``\`` character, which would
trigger escaping in normal Python strings.
backend : str, optional
Currently, there are two backends supported: ANTLR, and Lark.
The default setting is to use the ANTLR backend, which can be
changed to Lark if preferred.
Use ``backend="antlr"`` for the ANTLR-based parser, and
``backend="lark"`` for the Lark-based parser.
The ``backend`` option is case-sensitive, and must be in
all lowercase.
strict : bool, optional
This option is only available with the ANTLR backend.
If True, raise an exception if the string cannot be parsed as
valid LaTeX. If False, try to recover gracefully from common
mistakes.
Examples
========
>>> from sympy.parsing.latex import parse_latex
>>> expr = parse_latex(r"\frac {1 + \sqrt {\a}} {\b}")
>>> expr
(sqrt(a) + 1)/b
>>> expr.evalf(4, subs=dict(a=5, b=2))
1.618
>>> func = parse_latex(r"\int_1^\alpha \dfrac{\mathrm{d}t}{t}", backend="lark")
>>> func.evalf(subs={"alpha": 2})
0.693147180559945
"""
if backend == "antlr":
_latex = import_module(
'sympy.parsing.latex._parse_latex_antlr',
import_kwargs={'fromlist': ['X']})
if _latex is not None:
return _latex.parse_latex(s, strict)
elif backend == "lark":
return parse_latex_lark(s)
else:
raise NotImplementedError(f"Using the '{backend}' backend in the LaTeX" \
" parser is not supported.")
PK ]ZZZ��Q��
�
) sympy/parsing/latex/_build_latex_antlr.pyimport os
import subprocess
import glob
from sympy.utilities.misc import debug
here = os.path.dirname(__file__)
grammar_file = os.path.abspath(os.path.join(here, "LaTeX.g4"))
dir_latex_antlr = os.path.join(here, "_antlr")
header = '''\
# *** GENERATED BY `setup.py antlr`, DO NOT EDIT BY HAND ***
#
# Generated from ../LaTeX.g4, derived from latex2sympy
# latex2sympy is licensed under the MIT license
# https://github.com/augustt198/latex2sympy/blob/master/LICENSE.txt
#
# Generated with antlr4
# antlr4 is licensed under the BSD-3-Clause License
# https://github.com/antlr/antlr4/blob/master/LICENSE.txt
'''
def check_antlr_version():
debug("Checking antlr4 version...")
try:
debug(subprocess.check_output(["antlr4"])
.decode('utf-8').split("\n")[0])
return True
except (subprocess.CalledProcessError, FileNotFoundError):
debug("The 'antlr4' command line tool is not installed, "
"or not on your PATH.\n"
"> Please refer to the README.md file for more information.")
return False
def build_parser(output_dir=dir_latex_antlr):
check_antlr_version()
debug("Updating ANTLR-generated code in {}".format(output_dir))
if not os.path.exists(output_dir):
os.makedirs(output_dir)
with open(os.path.join(output_dir, "__init__.py"), "w+") as fp:
fp.write(header)
args = [
"antlr4",
grammar_file,
"-o", output_dir,
# for now, not generating these as latex2sympy did not use them
"-no-visitor",
"-no-listener",
]
debug("Running code generation...\n\t$ {}".format(" ".join(args)))
subprocess.check_output(args, cwd=output_dir)
debug("Applying headers, removing unnecessary files and renaming...")
# Handle case insensitive file systems. If the files are already
# generated, they will be written to latex* but LaTeX*.* won't match them.
for path in (glob.glob(os.path.join(output_dir, "LaTeX*.*")) or
glob.glob(os.path.join(output_dir, "latex*.*"))):
# Remove files ending in .interp or .tokens as they are not needed.
if not path.endswith(".py"):
os.unlink(path)
continue
new_path = os.path.join(output_dir, os.path.basename(path).lower())
with open(path, 'r') as f:
lines = [line.rstrip() + '\n' for line in f.readlines()]
os.unlink(path)
with open(new_path, "w") as out_file:
offset = 0
while lines[offset].startswith('#'):
offset += 1
out_file.write(header)
out_file.writelines(lines[offset:])
debug("\t{}".format(new_path))
return True
if __name__ == "__main__":
build_parser()
PK ]ZZZV =��P �P ) sympy/parsing/latex/_parse_latex_antlr.py# Ported from latex2sympy by @augustt198
# https://github.com/augustt198/latex2sympy
# See license in LICENSE.txt
from importlib.metadata import version
import sympy
from sympy.external import import_module
from sympy.printing.str import StrPrinter
from sympy.physics.quantum.state import Bra, Ket
from .errors import LaTeXParsingError
LaTeXParser = LaTeXLexer = MathErrorListener = None
try:
LaTeXParser = import_module('sympy.parsing.latex._antlr.latexparser',
import_kwargs={'fromlist': ['LaTeXParser']}).LaTeXParser
LaTeXLexer = import_module('sympy.parsing.latex._antlr.latexlexer',
import_kwargs={'fromlist': ['LaTeXLexer']}).LaTeXLexer
except Exception:
pass
ErrorListener = import_module('antlr4.error.ErrorListener',
warn_not_installed=True,
import_kwargs={'fromlist': ['ErrorListener']}
)
if ErrorListener:
class MathErrorListener(ErrorListener.ErrorListener): # type:ignore # noqa:F811
def __init__(self, src):
super(ErrorListener.ErrorListener, self).__init__()
self.src = src
def syntaxError(self, recog, symbol, line, col, msg, e):
fmt = "%s\n%s\n%s"
marker = "~" * col + "^"
if msg.startswith("missing"):
err = fmt % (msg, self.src, marker)
elif msg.startswith("no viable"):
err = fmt % ("I expected something else here", self.src, marker)
elif msg.startswith("mismatched"):
names = LaTeXParser.literalNames
expected = [
names[i] for i in e.getExpectedTokens() if i < len(names)
]
if len(expected) < 10:
expected = " ".join(expected)
err = (fmt % ("I expected one of these: " + expected, self.src,
marker))
else:
err = (fmt % ("I expected something else here", self.src,
marker))
else:
err = fmt % ("I don't understand this", self.src, marker)
raise LaTeXParsingError(err)
def parse_latex(sympy, strict=False):
antlr4 = import_module('antlr4')
if None in [antlr4, MathErrorListener] or \
not version('antlr4-python3-runtime').startswith('4.11'):
raise ImportError("LaTeX parsing requires the antlr4 Python package,"
" provided by pip (antlr4-python3-runtime) or"
" conda (antlr-python-runtime), version 4.11")
sympy = sympy.strip()
matherror = MathErrorListener(sympy)
stream = antlr4.InputStream(sympy)
lex = LaTeXLexer(stream)
lex.removeErrorListeners()
lex.addErrorListener(matherror)
tokens = antlr4.CommonTokenStream(lex)
parser = LaTeXParser(tokens)
# remove default console error listener
parser.removeErrorListeners()
parser.addErrorListener(matherror)
relation = parser.math().relation()
if strict and (relation.start.start != 0 or relation.stop.stop != len(sympy) - 1):
raise LaTeXParsingError("Invalid LaTeX")
expr = convert_relation(relation)
return expr
def convert_relation(rel):
if rel.expr():
return convert_expr(rel.expr())
lh = convert_relation(rel.relation(0))
rh = convert_relation(rel.relation(1))
if rel.LT():
return sympy.StrictLessThan(lh, rh)
elif rel.LTE():
return sympy.LessThan(lh, rh)
elif rel.GT():
return sympy.StrictGreaterThan(lh, rh)
elif rel.GTE():
return sympy.GreaterThan(lh, rh)
elif rel.EQUAL():
return sympy.Eq(lh, rh)
elif rel.NEQ():
return sympy.Ne(lh, rh)
def convert_expr(expr):
return convert_add(expr.additive())
def convert_add(add):
if add.ADD():
lh = convert_add(add.additive(0))
rh = convert_add(add.additive(1))
return sympy.Add(lh, rh, evaluate=False)
elif add.SUB():
lh = convert_add(add.additive(0))
rh = convert_add(add.additive(1))
if hasattr(rh, "is_Atom") and rh.is_Atom:
return sympy.Add(lh, -1 * rh, evaluate=False)
return sympy.Add(lh, sympy.Mul(-1, rh, evaluate=False), evaluate=False)
else:
return convert_mp(add.mp())
def convert_mp(mp):
if hasattr(mp, 'mp'):
mp_left = mp.mp(0)
mp_right = mp.mp(1)
else:
mp_left = mp.mp_nofunc(0)
mp_right = mp.mp_nofunc(1)
if mp.MUL() or mp.CMD_TIMES() or mp.CMD_CDOT():
lh = convert_mp(mp_left)
rh = convert_mp(mp_right)
return sympy.Mul(lh, rh, evaluate=False)
elif mp.DIV() or mp.CMD_DIV() or mp.COLON():
lh = convert_mp(mp_left)
rh = convert_mp(mp_right)
return sympy.Mul(lh, sympy.Pow(rh, -1, evaluate=False), evaluate=False)
else:
if hasattr(mp, 'unary'):
return convert_unary(mp.unary())
else:
return convert_unary(mp.unary_nofunc())
def convert_unary(unary):
if hasattr(unary, 'unary'):
nested_unary = unary.unary()
else:
nested_unary = unary.unary_nofunc()
if hasattr(unary, 'postfix_nofunc'):
first = unary.postfix()
tail = unary.postfix_nofunc()
postfix = [first] + tail
else:
postfix = unary.postfix()
if unary.ADD():
return convert_unary(nested_unary)
elif unary.SUB():
numabs = convert_unary(nested_unary)
# Use Integer(-n) instead of Mul(-1, n)
return -numabs
elif postfix:
return convert_postfix_list(postfix)
def convert_postfix_list(arr, i=0):
if i >= len(arr):
raise LaTeXParsingError("Index out of bounds")
res = convert_postfix(arr[i])
if isinstance(res, sympy.Expr):
if i == len(arr) - 1:
return res # nothing to multiply by
else:
if i > 0:
left = convert_postfix(arr[i - 1])
right = convert_postfix(arr[i + 1])
if isinstance(left, sympy.Expr) and isinstance(
right, sympy.Expr):
left_syms = convert_postfix(arr[i - 1]).atoms(sympy.Symbol)
right_syms = convert_postfix(arr[i + 1]).atoms(
sympy.Symbol)
# if the left and right sides contain no variables and the
# symbol in between is 'x', treat as multiplication.
if not (left_syms or right_syms) and str(res) == 'x':
return convert_postfix_list(arr, i + 1)
# multiply by next
return sympy.Mul(
res, convert_postfix_list(arr, i + 1), evaluate=False)
else: # must be derivative
wrt = res[0]
if i == len(arr) - 1:
raise LaTeXParsingError("Expected expression for derivative")
else:
expr = convert_postfix_list(arr, i + 1)
return sympy.Derivative(expr, wrt)
def do_subs(expr, at):
if at.expr():
at_expr = convert_expr(at.expr())
syms = at_expr.atoms(sympy.Symbol)
if len(syms) == 0:
return expr
elif len(syms) > 0:
sym = next(iter(syms))
return expr.subs(sym, at_expr)
elif at.equality():
lh = convert_expr(at.equality().expr(0))
rh = convert_expr(at.equality().expr(1))
return expr.subs(lh, rh)
def convert_postfix(postfix):
if hasattr(postfix, 'exp'):
exp_nested = postfix.exp()
else:
exp_nested = postfix.exp_nofunc()
exp = convert_exp(exp_nested)
for op in postfix.postfix_op():
if op.BANG():
if isinstance(exp, list):
raise LaTeXParsingError("Cannot apply postfix to derivative")
exp = sympy.factorial(exp, evaluate=False)
elif op.eval_at():
ev = op.eval_at()
at_b = None
at_a = None
if ev.eval_at_sup():
at_b = do_subs(exp, ev.eval_at_sup())
if ev.eval_at_sub():
at_a = do_subs(exp, ev.eval_at_sub())
if at_b is not None and at_a is not None:
exp = sympy.Add(at_b, -1 * at_a, evaluate=False)
elif at_b is not None:
exp = at_b
elif at_a is not None:
exp = at_a
return exp
def convert_exp(exp):
if hasattr(exp, 'exp'):
exp_nested = exp.exp()
else:
exp_nested = exp.exp_nofunc()
if exp_nested:
base = convert_exp(exp_nested)
if isinstance(base, list):
raise LaTeXParsingError("Cannot raise derivative to power")
if exp.atom():
exponent = convert_atom(exp.atom())
elif exp.expr():
exponent = convert_expr(exp.expr())
return sympy.Pow(base, exponent, evaluate=False)
else:
if hasattr(exp, 'comp'):
return convert_comp(exp.comp())
else:
return convert_comp(exp.comp_nofunc())
def convert_comp(comp):
if comp.group():
return convert_expr(comp.group().expr())
elif comp.abs_group():
return sympy.Abs(convert_expr(comp.abs_group().expr()), evaluate=False)
elif comp.atom():
return convert_atom(comp.atom())
elif comp.floor():
return convert_floor(comp.floor())
elif comp.ceil():
return convert_ceil(comp.ceil())
elif comp.func():
return convert_func(comp.func())
def convert_atom(atom):
if atom.LETTER():
sname = atom.LETTER().getText()
if atom.subexpr():
if atom.subexpr().expr(): # subscript is expr
subscript = convert_expr(atom.subexpr().expr())
else: # subscript is atom
subscript = convert_atom(atom.subexpr().atom())
sname += '_{' + StrPrinter().doprint(subscript) + '}'
if atom.SINGLE_QUOTES():
sname += atom.SINGLE_QUOTES().getText() # put after subscript for easy identify
return sympy.Symbol(sname)
elif atom.SYMBOL():
s = atom.SYMBOL().getText()[1:]
if s == "infty":
return sympy.oo
else:
if atom.subexpr():
subscript = None
if atom.subexpr().expr(): # subscript is expr
subscript = convert_expr(atom.subexpr().expr())
else: # subscript is atom
subscript = convert_atom(atom.subexpr().atom())
subscriptName = StrPrinter().doprint(subscript)
s += '_{' + subscriptName + '}'
return sympy.Symbol(s)
elif atom.number():
s = atom.number().getText().replace(",", "")
return sympy.Number(s)
elif atom.DIFFERENTIAL():
var = get_differential_var(atom.DIFFERENTIAL())
return sympy.Symbol('d' + var.name)
elif atom.mathit():
text = rule2text(atom.mathit().mathit_text())
return sympy.Symbol(text)
elif atom.frac():
return convert_frac(atom.frac())
elif atom.binom():
return convert_binom(atom.binom())
elif atom.bra():
val = convert_expr(atom.bra().expr())
return Bra(val)
elif atom.ket():
val = convert_expr(atom.ket().expr())
return Ket(val)
def rule2text(ctx):
stream = ctx.start.getInputStream()
# starting index of starting token
startIdx = ctx.start.start
# stopping index of stopping token
stopIdx = ctx.stop.stop
return stream.getText(startIdx, stopIdx)
def convert_frac(frac):
diff_op = False
partial_op = False
if frac.lower and frac.upper:
lower_itv = frac.lower.getSourceInterval()
lower_itv_len = lower_itv[1] - lower_itv[0] + 1
if (frac.lower.start == frac.lower.stop
and frac.lower.start.type == LaTeXLexer.DIFFERENTIAL):
wrt = get_differential_var_str(frac.lower.start.text)
diff_op = True
elif (lower_itv_len == 2 and frac.lower.start.type == LaTeXLexer.SYMBOL
and frac.lower.start.text == '\\partial'
and (frac.lower.stop.type == LaTeXLexer.LETTER
or frac.lower.stop.type == LaTeXLexer.SYMBOL)):
partial_op = True
wrt = frac.lower.stop.text
if frac.lower.stop.type == LaTeXLexer.SYMBOL:
wrt = wrt[1:]
if diff_op or partial_op:
wrt = sympy.Symbol(wrt)
if (diff_op and frac.upper.start == frac.upper.stop
and frac.upper.start.type == LaTeXLexer.LETTER
and frac.upper.start.text == 'd'):
return [wrt]
elif (partial_op and frac.upper.start == frac.upper.stop
and frac.upper.start.type == LaTeXLexer.SYMBOL
and frac.upper.start.text == '\\partial'):
return [wrt]
upper_text = rule2text(frac.upper)
expr_top = None
if diff_op and upper_text.startswith('d'):
expr_top = parse_latex(upper_text[1:])
elif partial_op and frac.upper.start.text == '\\partial':
expr_top = parse_latex(upper_text[len('\\partial'):])
if expr_top:
return sympy.Derivative(expr_top, wrt)
if frac.upper:
expr_top = convert_expr(frac.upper)
else:
expr_top = sympy.Number(frac.upperd.text)
if frac.lower:
expr_bot = convert_expr(frac.lower)
else:
expr_bot = sympy.Number(frac.lowerd.text)
inverse_denom = sympy.Pow(expr_bot, -1, evaluate=False)
if expr_top == 1:
return inverse_denom
else:
return sympy.Mul(expr_top, inverse_denom, evaluate=False)
def convert_binom(binom):
expr_n = convert_expr(binom.n)
expr_k = convert_expr(binom.k)
return sympy.binomial(expr_n, expr_k, evaluate=False)
def convert_floor(floor):
val = convert_expr(floor.val)
return sympy.floor(val, evaluate=False)
def convert_ceil(ceil):
val = convert_expr(ceil.val)
return sympy.ceiling(val, evaluate=False)
def convert_func(func):
if func.func_normal():
if func.L_PAREN(): # function called with parenthesis
arg = convert_func_arg(func.func_arg())
else:
arg = convert_func_arg(func.func_arg_noparens())
name = func.func_normal().start.text[1:]
# change arc<trig> -> a<trig>
if name in [
"arcsin", "arccos", "arctan", "arccsc", "arcsec", "arccot"
]:
name = "a" + name[3:]
expr = getattr(sympy.functions, name)(arg, evaluate=False)
if name in ["arsinh", "arcosh", "artanh"]:
name = "a" + name[2:]
expr = getattr(sympy.functions, name)(arg, evaluate=False)
if name == "exp":
expr = sympy.exp(arg, evaluate=False)
if name in ("log", "lg", "ln"):
if func.subexpr():
if func.subexpr().expr():
base = convert_expr(func.subexpr().expr())
else:
base = convert_atom(func.subexpr().atom())
elif name == "lg": # ISO 80000-2:2019
base = 10
elif name in ("ln", "log"): # SymPy's latex printer prints ln as log by default
base = sympy.E
expr = sympy.log(arg, base, evaluate=False)
func_pow = None
should_pow = True
if func.supexpr():
if func.supexpr().expr():
func_pow = convert_expr(func.supexpr().expr())
else:
func_pow = convert_atom(func.supexpr().atom())
if name in [
"sin", "cos", "tan", "csc", "sec", "cot", "sinh", "cosh",
"tanh"
]:
if func_pow == -1:
name = "a" + name
should_pow = False
expr = getattr(sympy.functions, name)(arg, evaluate=False)
if func_pow and should_pow:
expr = sympy.Pow(expr, func_pow, evaluate=False)
return expr
elif func.LETTER() or func.SYMBOL():
if func.LETTER():
fname = func.LETTER().getText()
elif func.SYMBOL():
fname = func.SYMBOL().getText()[1:]
fname = str(fname) # can't be unicode
if func.subexpr():
if func.subexpr().expr(): # subscript is expr
subscript = convert_expr(func.subexpr().expr())
else: # subscript is atom
subscript = convert_atom(func.subexpr().atom())
subscriptName = StrPrinter().doprint(subscript)
fname += '_{' + subscriptName + '}'
if func.SINGLE_QUOTES():
fname += func.SINGLE_QUOTES().getText()
input_args = func.args()
output_args = []
while input_args.args(): # handle multiple arguments to function
output_args.append(convert_expr(input_args.expr()))
input_args = input_args.args()
output_args.append(convert_expr(input_args.expr()))
return sympy.Function(fname)(*output_args)
elif func.FUNC_INT():
return handle_integral(func)
elif func.FUNC_SQRT():
expr = convert_expr(func.base)
if func.root:
r = convert_expr(func.root)
return sympy.root(expr, r, evaluate=False)
else:
return sympy.sqrt(expr, evaluate=False)
elif func.FUNC_OVERLINE():
expr = convert_expr(func.base)
return sympy.conjugate(expr, evaluate=False)
elif func.FUNC_SUM():
return handle_sum_or_prod(func, "summation")
elif func.FUNC_PROD():
return handle_sum_or_prod(func, "product")
elif func.FUNC_LIM():
return handle_limit(func)
def convert_func_arg(arg):
if hasattr(arg, 'expr'):
return convert_expr(arg.expr())
else:
return convert_mp(arg.mp_nofunc())
def handle_integral(func):
if func.additive():
integrand = convert_add(func.additive())
elif func.frac():
integrand = convert_frac(func.frac())
else:
integrand = 1
int_var = None
if func.DIFFERENTIAL():
int_var = get_differential_var(func.DIFFERENTIAL())
else:
for sym in integrand.atoms(sympy.Symbol):
s = str(sym)
if len(s) > 1 and s[0] == 'd':
if s[1] == '\\':
int_var = sympy.Symbol(s[2:])
else:
int_var = sympy.Symbol(s[1:])
int_sym = sym
if int_var:
integrand = integrand.subs(int_sym, 1)
else:
# Assume dx by default
int_var = sympy.Symbol('x')
if func.subexpr():
if func.subexpr().atom():
lower = convert_atom(func.subexpr().atom())
else:
lower = convert_expr(func.subexpr().expr())
if func.supexpr().atom():
upper = convert_atom(func.supexpr().atom())
else:
upper = convert_expr(func.supexpr().expr())
return sympy.Integral(integrand, (int_var, lower, upper))
else:
return sympy.Integral(integrand, int_var)
def handle_sum_or_prod(func, name):
val = convert_mp(func.mp())
iter_var = convert_expr(func.subeq().equality().expr(0))
start = convert_expr(func.subeq().equality().expr(1))
if func.supexpr().expr(): # ^{expr}
end = convert_expr(func.supexpr().expr())
else: # ^atom
end = convert_atom(func.supexpr().atom())
if name == "summation":
return sympy.Sum(val, (iter_var, start, end))
elif name == "product":
return sympy.Product(val, (iter_var, start, end))
def handle_limit(func):
sub = func.limit_sub()
if sub.LETTER():
var = sympy.Symbol(sub.LETTER().getText())
elif sub.SYMBOL():
var = sympy.Symbol(sub.SYMBOL().getText()[1:])
else:
var = sympy.Symbol('x')
if sub.SUB():
direction = "-"
elif sub.ADD():
direction = "+"
else:
direction = "+-"
approaching = convert_expr(sub.expr())
content = convert_mp(func.mp())
return sympy.Limit(content, var, approaching, direction)
def get_differential_var(d):
text = get_differential_var_str(d.getText())
return sympy.Symbol(text)
def get_differential_var_str(text):
for i in range(1, len(text)):
c = text[i]
if not (c == " " or c == "\r" or c == "\n" or c == "\t"):
idx = i
break
text = text[idx:]
if text[0] == "\\":
text = text[1:]
return text
PK ]ZZZ᭥- - sympy/parsing/latex/errors.pyclass LaTeXParsingError(Exception):
pass
PK ]ZZZ58ǥ� � & sympy/parsing/latex/_antlr/__init__.py# *** GENERATED BY `setup.py antlr`, DO NOT EDIT BY HAND ***
#
# Generated from ../LaTeX.g4, derived from latex2sympy
# latex2sympy is licensed under the MIT license
# https://github.com/augustt198/latex2sympy/blob/master/LICENSE.txt
#
# Generated with antlr4
# antlr4 is licensed under the BSD-3-Clause License
# https://github.com/antlr/antlr4/blob/master/LICENSE.txt
PK ]ZZZ���&w &w ( sympy/parsing/latex/_antlr/latexlexer.py# *** GENERATED BY `setup.py antlr`, DO NOT EDIT BY HAND ***
#
# Generated from ../LaTeX.g4, derived from latex2sympy
# latex2sympy is licensed under the MIT license
# https://github.com/augustt198/latex2sympy/blob/master/LICENSE.txt
#
# Generated with antlr4
# antlr4 is licensed under the BSD-3-Clause License
# https://github.com/antlr/antlr4/blob/master/LICENSE.txt
from antlr4 import *
from io import StringIO
import sys
if sys.version_info[1] > 5:
from typing import TextIO
else:
from typing.io import TextIO
def serializedATN():
return [
4,0,91,911,6,-1,2,0,7,0,2,1,7,1,2,2,7,2,2,3,7,3,2,4,7,4,2,5,7,5,
2,6,7,6,2,7,7,7,2,8,7,8,2,9,7,9,2,10,7,10,2,11,7,11,2,12,7,12,2,
13,7,13,2,14,7,14,2,15,7,15,2,16,7,16,2,17,7,17,2,18,7,18,2,19,7,
19,2,20,7,20,2,21,7,21,2,22,7,22,2,23,7,23,2,24,7,24,2,25,7,25,2,
26,7,26,2,27,7,27,2,28,7,28,2,29,7,29,2,30,7,30,2,31,7,31,2,32,7,
32,2,33,7,33,2,34,7,34,2,35,7,35,2,36,7,36,2,37,7,37,2,38,7,38,2,
39,7,39,2,40,7,40,2,41,7,41,2,42,7,42,2,43,7,43,2,44,7,44,2,45,7,
45,2,46,7,46,2,47,7,47,2,48,7,48,2,49,7,49,2,50,7,50,2,51,7,51,2,
52,7,52,2,53,7,53,2,54,7,54,2,55,7,55,2,56,7,56,2,57,7,57,2,58,7,
58,2,59,7,59,2,60,7,60,2,61,7,61,2,62,7,62,2,63,7,63,2,64,7,64,2,
65,7,65,2,66,7,66,2,67,7,67,2,68,7,68,2,69,7,69,2,70,7,70,2,71,7,
71,2,72,7,72,2,73,7,73,2,74,7,74,2,75,7,75,2,76,7,76,2,77,7,77,2,
78,7,78,2,79,7,79,2,80,7,80,2,81,7,81,2,82,7,82,2,83,7,83,2,84,7,
84,2,85,7,85,2,86,7,86,2,87,7,87,2,88,7,88,2,89,7,89,2,90,7,90,2,
91,7,91,1,0,1,0,1,1,1,1,1,2,4,2,191,8,2,11,2,12,2,192,1,2,1,2,1,
3,1,3,1,3,1,3,1,3,1,3,1,3,1,3,1,3,1,3,1,3,1,3,3,3,209,8,3,1,3,1,
3,1,4,1,4,1,4,1,4,1,4,1,4,1,4,1,4,1,4,1,4,1,4,3,4,224,8,4,1,4,1,
4,1,5,1,5,1,5,1,5,1,5,1,5,1,5,1,5,1,5,1,5,1,5,1,5,1,5,3,5,241,8,
5,1,5,1,5,1,6,1,6,1,6,1,6,1,6,1,6,1,6,1,6,1,7,1,7,1,7,1,7,1,7,1,
7,1,7,1,7,1,7,1,8,1,8,1,8,1,8,1,8,1,8,1,8,1,8,1,8,1,8,1,8,1,8,1,
8,1,8,1,8,3,8,277,8,8,1,8,1,8,1,9,1,9,1,9,1,9,1,9,1,9,1,9,1,9,1,
9,1,9,1,9,1,9,1,9,1,9,1,9,1,10,1,10,1,10,1,10,1,10,1,10,1,10,1,10,
1,10,1,10,1,10,1,10,1,10,1,10,1,10,1,10,1,10,1,11,1,11,1,11,1,11,
1,11,1,11,1,11,1,11,1,12,1,12,1,12,1,12,1,12,1,12,1,12,1,12,1,12,
1,13,1,13,1,13,1,13,1,13,1,13,1,13,1,13,1,13,1,13,1,13,1,13,1,13,
1,13,1,13,1,13,1,13,1,13,1,13,1,13,1,13,1,13,1,13,1,13,1,13,1,13,
1,13,1,13,1,13,1,13,1,13,1,13,1,13,1,13,1,13,1,13,1,13,1,13,1,13,
1,13,1,13,1,13,1,13,1,13,1,13,1,13,1,13,1,13,1,13,1,13,1,13,3,13,
381,8,13,1,13,1,13,1,14,1,14,1,15,1,15,1,16,1,16,1,17,1,17,1,18,
1,18,1,19,1,19,1,20,1,20,1,21,1,21,1,22,1,22,1,22,1,23,1,23,1,23,
1,24,1,24,1,25,1,25,1,26,1,26,1,27,1,27,1,27,1,27,1,27,1,27,1,27,
1,27,1,28,1,28,1,28,1,28,1,28,1,28,1,28,1,29,1,29,1,29,1,29,1,29,
1,29,1,29,1,29,1,30,1,30,1,30,1,30,1,30,1,30,1,30,1,30,1,31,1,31,
1,31,1,31,1,31,1,32,1,32,1,32,1,32,1,32,1,32,1,32,1,32,1,32,1,32,
1,32,1,32,1,32,1,32,1,32,1,32,1,32,1,32,1,32,1,32,1,32,1,32,1,32,
1,32,1,32,1,32,1,32,1,32,1,32,1,32,1,32,1,32,1,32,1,32,1,32,1,32,
1,32,1,32,1,32,1,32,1,32,1,32,1,32,1,32,1,32,1,32,1,32,1,32,1,32,
1,32,1,32,1,32,1,32,1,32,1,32,3,32,504,8,32,1,33,1,33,1,33,1,33,
1,33,1,33,1,33,1,33,1,33,1,33,1,33,1,33,1,33,1,33,1,33,3,33,521,
8,33,1,34,1,34,1,34,1,34,1,34,1,35,1,35,1,35,1,35,1,35,1,35,1,36,
1,36,1,36,1,36,1,36,1,37,1,37,1,37,1,37,1,37,1,38,1,38,1,38,1,38,
1,39,1,39,1,39,1,39,1,40,1,40,1,40,1,40,1,40,1,41,1,41,1,41,1,41,
1,41,1,42,1,42,1,42,1,42,1,42,1,43,1,43,1,43,1,43,1,43,1,44,1,44,
1,44,1,44,1,44,1,45,1,45,1,45,1,45,1,45,1,46,1,46,1,46,1,46,1,46,
1,46,1,46,1,46,1,47,1,47,1,47,1,47,1,47,1,47,1,47,1,47,1,48,1,48,
1,48,1,48,1,48,1,48,1,48,1,48,1,49,1,49,1,49,1,49,1,49,1,49,1,49,
1,49,1,50,1,50,1,50,1,50,1,50,1,50,1,50,1,50,1,51,1,51,1,51,1,51,
1,51,1,51,1,51,1,51,1,52,1,52,1,52,1,52,1,52,1,52,1,53,1,53,1,53,
1,53,1,53,1,53,1,54,1,54,1,54,1,54,1,54,1,54,1,55,1,55,1,55,1,55,
1,55,1,55,1,55,1,55,1,56,1,56,1,56,1,56,1,56,1,56,1,56,1,56,1,57,
1,57,1,57,1,57,1,57,1,57,1,57,1,57,1,58,1,58,1,58,1,58,1,58,1,58,
1,58,1,58,1,59,1,59,1,59,1,59,1,59,1,59,1,59,1,59,1,60,1,60,1,60,
1,60,1,60,1,60,1,60,1,61,1,61,1,61,1,61,1,61,1,61,1,61,1,62,1,62,
1,62,1,62,1,62,1,62,1,63,1,63,1,63,1,63,1,63,1,63,1,63,1,63,1,63,
1,63,1,64,1,64,1,64,1,64,1,64,1,64,1,64,1,65,1,65,1,65,1,65,1,65,
1,65,1,66,1,66,1,66,1,66,1,66,1,67,1,67,1,67,1,67,1,67,1,67,1,67,
1,67,1,67,1,67,1,67,1,67,1,67,1,67,1,67,1,67,1,67,3,67,753,8,67,
1,68,1,68,1,68,1,68,1,68,1,68,1,68,1,69,1,69,1,69,1,69,1,69,1,69,
1,69,1,69,1,70,1,70,1,70,1,70,1,70,1,70,1,70,1,70,1,71,1,71,1,71,
1,71,1,71,1,71,1,71,1,71,1,72,1,72,1,73,1,73,1,74,1,74,1,75,1,75,
1,76,1,76,5,76,796,8,76,10,76,12,76,799,9,76,1,76,1,76,1,76,4,76,
804,8,76,11,76,12,76,805,3,76,808,8,76,1,77,1,77,1,78,1,78,1,79,
1,79,5,79,816,8,79,10,79,12,79,819,9,79,3,79,821,8,79,1,79,1,79,
1,79,5,79,826,8,79,10,79,12,79,829,9,79,1,79,3,79,832,8,79,3,79,
834,8,79,1,80,1,80,1,80,1,80,1,80,1,81,1,81,1,82,1,82,1,82,1,82,
1,82,1,82,1,82,1,82,1,82,3,82,852,8,82,1,83,1,83,1,83,1,83,1,83,
1,83,1,84,1,84,1,84,1,84,1,84,1,84,1,84,1,84,1,84,1,84,1,85,1,85,
1,86,1,86,1,86,1,86,1,86,1,86,1,86,1,86,1,86,3,86,881,8,86,1,87,
1,87,1,87,1,87,1,87,1,87,1,88,1,88,1,88,1,88,1,88,1,88,1,88,1,88,
1,88,1,88,1,89,1,89,1,90,4,90,902,8,90,11,90,12,90,903,1,91,1,91,
4,91,908,8,91,11,91,12,91,909,3,797,817,827,0,92,1,1,3,2,5,3,7,4,
9,5,11,6,13,7,15,8,17,9,19,10,21,11,23,12,25,13,27,14,29,15,31,16,
33,17,35,18,37,19,39,20,41,21,43,22,45,23,47,24,49,25,51,26,53,27,
55,28,57,29,59,30,61,31,63,32,65,33,67,34,69,35,71,36,73,37,75,38,
77,39,79,40,81,41,83,42,85,43,87,44,89,45,91,46,93,47,95,48,97,49,
99,50,101,51,103,52,105,53,107,54,109,55,111,56,113,57,115,58,117,
59,119,60,121,61,123,62,125,63,127,64,129,65,131,66,133,67,135,68,
137,69,139,70,141,71,143,72,145,73,147,74,149,75,151,0,153,76,155,
77,157,78,159,79,161,80,163,81,165,82,167,83,169,84,171,85,173,86,
175,87,177,88,179,89,181,90,183,91,1,0,3,3,0,9,10,13,13,32,32,2,
0,65,90,97,122,1,0,48,57,949,0,1,1,0,0,0,0,3,1,0,0,0,0,5,1,0,0,0,
0,7,1,0,0,0,0,9,1,0,0,0,0,11,1,0,0,0,0,13,1,0,0,0,0,15,1,0,0,0,0,
17,1,0,0,0,0,19,1,0,0,0,0,21,1,0,0,0,0,23,1,0,0,0,0,25,1,0,0,0,0,
27,1,0,0,0,0,29,1,0,0,0,0,31,1,0,0,0,0,33,1,0,0,0,0,35,1,0,0,0,0,
37,1,0,0,0,0,39,1,0,0,0,0,41,1,0,0,0,0,43,1,0,0,0,0,45,1,0,0,0,0,
47,1,0,0,0,0,49,1,0,0,0,0,51,1,0,0,0,0,53,1,0,0,0,0,55,1,0,0,0,0,
57,1,0,0,0,0,59,1,0,0,0,0,61,1,0,0,0,0,63,1,0,0,0,0,65,1,0,0,0,0,
67,1,0,0,0,0,69,1,0,0,0,0,71,1,0,0,0,0,73,1,0,0,0,0,75,1,0,0,0,0,
77,1,0,0,0,0,79,1,0,0,0,0,81,1,0,0,0,0,83,1,0,0,0,0,85,1,0,0,0,0,
87,1,0,0,0,0,89,1,0,0,0,0,91,1,0,0,0,0,93,1,0,0,0,0,95,1,0,0,0,0,
97,1,0,0,0,0,99,1,0,0,0,0,101,1,0,0,0,0,103,1,0,0,0,0,105,1,0,0,
0,0,107,1,0,0,0,0,109,1,0,0,0,0,111,1,0,0,0,0,113,1,0,0,0,0,115,
1,0,0,0,0,117,1,0,0,0,0,119,1,0,0,0,0,121,1,0,0,0,0,123,1,0,0,0,
0,125,1,0,0,0,0,127,1,0,0,0,0,129,1,0,0,0,0,131,1,0,0,0,0,133,1,
0,0,0,0,135,1,0,0,0,0,137,1,0,0,0,0,139,1,0,0,0,0,141,1,0,0,0,0,
143,1,0,0,0,0,145,1,0,0,0,0,147,1,0,0,0,0,149,1,0,0,0,0,153,1,0,
0,0,0,155,1,0,0,0,0,157,1,0,0,0,0,159,1,0,0,0,0,161,1,0,0,0,0,163,
1,0,0,0,0,165,1,0,0,0,0,167,1,0,0,0,0,169,1,0,0,0,0,171,1,0,0,0,
0,173,1,0,0,0,0,175,1,0,0,0,0,177,1,0,0,0,0,179,1,0,0,0,0,181,1,
0,0,0,0,183,1,0,0,0,1,185,1,0,0,0,3,187,1,0,0,0,5,190,1,0,0,0,7,
208,1,0,0,0,9,223,1,0,0,0,11,240,1,0,0,0,13,244,1,0,0,0,15,252,1,
0,0,0,17,276,1,0,0,0,19,280,1,0,0,0,21,295,1,0,0,0,23,312,1,0,0,
0,25,320,1,0,0,0,27,380,1,0,0,0,29,384,1,0,0,0,31,386,1,0,0,0,33,
388,1,0,0,0,35,390,1,0,0,0,37,392,1,0,0,0,39,394,1,0,0,0,41,396,
1,0,0,0,43,398,1,0,0,0,45,400,1,0,0,0,47,403,1,0,0,0,49,406,1,0,
0,0,51,408,1,0,0,0,53,410,1,0,0,0,55,412,1,0,0,0,57,420,1,0,0,0,
59,427,1,0,0,0,61,435,1,0,0,0,63,443,1,0,0,0,65,503,1,0,0,0,67,520,
1,0,0,0,69,522,1,0,0,0,71,527,1,0,0,0,73,533,1,0,0,0,75,538,1,0,
0,0,77,543,1,0,0,0,79,547,1,0,0,0,81,551,1,0,0,0,83,556,1,0,0,0,
85,561,1,0,0,0,87,566,1,0,0,0,89,571,1,0,0,0,91,576,1,0,0,0,93,581,
1,0,0,0,95,589,1,0,0,0,97,597,1,0,0,0,99,605,1,0,0,0,101,613,1,0,
0,0,103,621,1,0,0,0,105,629,1,0,0,0,107,635,1,0,0,0,109,641,1,0,
0,0,111,647,1,0,0,0,113,655,1,0,0,0,115,663,1,0,0,0,117,671,1,0,
0,0,119,679,1,0,0,0,121,687,1,0,0,0,123,694,1,0,0,0,125,701,1,0,
0,0,127,707,1,0,0,0,129,717,1,0,0,0,131,724,1,0,0,0,133,730,1,0,
0,0,135,752,1,0,0,0,137,754,1,0,0,0,139,761,1,0,0,0,141,769,1,0,
0,0,143,777,1,0,0,0,145,785,1,0,0,0,147,787,1,0,0,0,149,789,1,0,
0,0,151,791,1,0,0,0,153,793,1,0,0,0,155,809,1,0,0,0,157,811,1,0,
0,0,159,833,1,0,0,0,161,835,1,0,0,0,163,840,1,0,0,0,165,851,1,0,
0,0,167,853,1,0,0,0,169,859,1,0,0,0,171,869,1,0,0,0,173,880,1,0,
0,0,175,882,1,0,0,0,177,888,1,0,0,0,179,898,1,0,0,0,181,901,1,0,
0,0,183,905,1,0,0,0,185,186,5,44,0,0,186,2,1,0,0,0,187,188,5,46,
0,0,188,4,1,0,0,0,189,191,7,0,0,0,190,189,1,0,0,0,191,192,1,0,0,
0,192,190,1,0,0,0,192,193,1,0,0,0,193,194,1,0,0,0,194,195,6,2,0,
0,195,6,1,0,0,0,196,197,5,92,0,0,197,209,5,44,0,0,198,199,5,92,0,
0,199,200,5,116,0,0,200,201,5,104,0,0,201,202,5,105,0,0,202,203,
5,110,0,0,203,204,5,115,0,0,204,205,5,112,0,0,205,206,5,97,0,0,206,
207,5,99,0,0,207,209,5,101,0,0,208,196,1,0,0,0,208,198,1,0,0,0,209,
210,1,0,0,0,210,211,6,3,0,0,211,8,1,0,0,0,212,213,5,92,0,0,213,224,
5,58,0,0,214,215,5,92,0,0,215,216,5,109,0,0,216,217,5,101,0,0,217,
218,5,100,0,0,218,219,5,115,0,0,219,220,5,112,0,0,220,221,5,97,0,
0,221,222,5,99,0,0,222,224,5,101,0,0,223,212,1,0,0,0,223,214,1,0,
0,0,224,225,1,0,0,0,225,226,6,4,0,0,226,10,1,0,0,0,227,228,5,92,
0,0,228,241,5,59,0,0,229,230,5,92,0,0,230,231,5,116,0,0,231,232,
5,104,0,0,232,233,5,105,0,0,233,234,5,99,0,0,234,235,5,107,0,0,235,
236,5,115,0,0,236,237,5,112,0,0,237,238,5,97,0,0,238,239,5,99,0,
0,239,241,5,101,0,0,240,227,1,0,0,0,240,229,1,0,0,0,241,242,1,0,
0,0,242,243,6,5,0,0,243,12,1,0,0,0,244,245,5,92,0,0,245,246,5,113,
0,0,246,247,5,117,0,0,247,248,5,97,0,0,248,249,5,100,0,0,249,250,
1,0,0,0,250,251,6,6,0,0,251,14,1,0,0,0,252,253,5,92,0,0,253,254,
5,113,0,0,254,255,5,113,0,0,255,256,5,117,0,0,256,257,5,97,0,0,257,
258,5,100,0,0,258,259,1,0,0,0,259,260,6,7,0,0,260,16,1,0,0,0,261,
262,5,92,0,0,262,277,5,33,0,0,263,264,5,92,0,0,264,265,5,110,0,0,
265,266,5,101,0,0,266,267,5,103,0,0,267,268,5,116,0,0,268,269,5,
104,0,0,269,270,5,105,0,0,270,271,5,110,0,0,271,272,5,115,0,0,272,
273,5,112,0,0,273,274,5,97,0,0,274,275,5,99,0,0,275,277,5,101,0,
0,276,261,1,0,0,0,276,263,1,0,0,0,277,278,1,0,0,0,278,279,6,8,0,
0,279,18,1,0,0,0,280,281,5,92,0,0,281,282,5,110,0,0,282,283,5,101,
0,0,283,284,5,103,0,0,284,285,5,109,0,0,285,286,5,101,0,0,286,287,
5,100,0,0,287,288,5,115,0,0,288,289,5,112,0,0,289,290,5,97,0,0,290,
291,5,99,0,0,291,292,5,101,0,0,292,293,1,0,0,0,293,294,6,9,0,0,294,
20,1,0,0,0,295,296,5,92,0,0,296,297,5,110,0,0,297,298,5,101,0,0,
298,299,5,103,0,0,299,300,5,116,0,0,300,301,5,104,0,0,301,302,5,
105,0,0,302,303,5,99,0,0,303,304,5,107,0,0,304,305,5,115,0,0,305,
306,5,112,0,0,306,307,5,97,0,0,307,308,5,99,0,0,308,309,5,101,0,
0,309,310,1,0,0,0,310,311,6,10,0,0,311,22,1,0,0,0,312,313,5,92,0,
0,313,314,5,108,0,0,314,315,5,101,0,0,315,316,5,102,0,0,316,317,
5,116,0,0,317,318,1,0,0,0,318,319,6,11,0,0,319,24,1,0,0,0,320,321,
5,92,0,0,321,322,5,114,0,0,322,323,5,105,0,0,323,324,5,103,0,0,324,
325,5,104,0,0,325,326,5,116,0,0,326,327,1,0,0,0,327,328,6,12,0,0,
328,26,1,0,0,0,329,330,5,92,0,0,330,331,5,118,0,0,331,332,5,114,
0,0,332,333,5,117,0,0,333,334,5,108,0,0,334,381,5,101,0,0,335,336,
5,92,0,0,336,337,5,118,0,0,337,338,5,99,0,0,338,339,5,101,0,0,339,
340,5,110,0,0,340,341,5,116,0,0,341,342,5,101,0,0,342,381,5,114,
0,0,343,344,5,92,0,0,344,345,5,118,0,0,345,346,5,98,0,0,346,347,
5,111,0,0,347,381,5,120,0,0,348,349,5,92,0,0,349,350,5,118,0,0,350,
351,5,115,0,0,351,352,5,107,0,0,352,353,5,105,0,0,353,381,5,112,
0,0,354,355,5,92,0,0,355,356,5,118,0,0,356,357,5,115,0,0,357,358,
5,112,0,0,358,359,5,97,0,0,359,360,5,99,0,0,360,381,5,101,0,0,361,
362,5,92,0,0,362,363,5,104,0,0,363,364,5,102,0,0,364,365,5,105,0,
0,365,381,5,108,0,0,366,367,5,92,0,0,367,381,5,42,0,0,368,369,5,
92,0,0,369,381,5,45,0,0,370,371,5,92,0,0,371,381,5,46,0,0,372,373,
5,92,0,0,373,381,5,47,0,0,374,375,5,92,0,0,375,381,5,34,0,0,376,
377,5,92,0,0,377,381,5,40,0,0,378,379,5,92,0,0,379,381,5,61,0,0,
380,329,1,0,0,0,380,335,1,0,0,0,380,343,1,0,0,0,380,348,1,0,0,0,
380,354,1,0,0,0,380,361,1,0,0,0,380,366,1,0,0,0,380,368,1,0,0,0,
380,370,1,0,0,0,380,372,1,0,0,0,380,374,1,0,0,0,380,376,1,0,0,0,
380,378,1,0,0,0,381,382,1,0,0,0,382,383,6,13,0,0,383,28,1,0,0,0,
384,385,5,43,0,0,385,30,1,0,0,0,386,387,5,45,0,0,387,32,1,0,0,0,
388,389,5,42,0,0,389,34,1,0,0,0,390,391,5,47,0,0,391,36,1,0,0,0,
392,393,5,40,0,0,393,38,1,0,0,0,394,395,5,41,0,0,395,40,1,0,0,0,
396,397,5,123,0,0,397,42,1,0,0,0,398,399,5,125,0,0,399,44,1,0,0,
0,400,401,5,92,0,0,401,402,5,123,0,0,402,46,1,0,0,0,403,404,5,92,
0,0,404,405,5,125,0,0,405,48,1,0,0,0,406,407,5,91,0,0,407,50,1,0,
0,0,408,409,5,93,0,0,409,52,1,0,0,0,410,411,5,124,0,0,411,54,1,0,
0,0,412,413,5,92,0,0,413,414,5,114,0,0,414,415,5,105,0,0,415,416,
5,103,0,0,416,417,5,104,0,0,417,418,5,116,0,0,418,419,5,124,0,0,
419,56,1,0,0,0,420,421,5,92,0,0,421,422,5,108,0,0,422,423,5,101,
0,0,423,424,5,102,0,0,424,425,5,116,0,0,425,426,5,124,0,0,426,58,
1,0,0,0,427,428,5,92,0,0,428,429,5,108,0,0,429,430,5,97,0,0,430,
431,5,110,0,0,431,432,5,103,0,0,432,433,5,108,0,0,433,434,5,101,
0,0,434,60,1,0,0,0,435,436,5,92,0,0,436,437,5,114,0,0,437,438,5,
97,0,0,438,439,5,110,0,0,439,440,5,103,0,0,440,441,5,108,0,0,441,
442,5,101,0,0,442,62,1,0,0,0,443,444,5,92,0,0,444,445,5,108,0,0,
445,446,5,105,0,0,446,447,5,109,0,0,447,64,1,0,0,0,448,449,5,92,
0,0,449,450,5,116,0,0,450,504,5,111,0,0,451,452,5,92,0,0,452,453,
5,114,0,0,453,454,5,105,0,0,454,455,5,103,0,0,455,456,5,104,0,0,
456,457,5,116,0,0,457,458,5,97,0,0,458,459,5,114,0,0,459,460,5,114,
0,0,460,461,5,111,0,0,461,504,5,119,0,0,462,463,5,92,0,0,463,464,
5,82,0,0,464,465,5,105,0,0,465,466,5,103,0,0,466,467,5,104,0,0,467,
468,5,116,0,0,468,469,5,97,0,0,469,470,5,114,0,0,470,471,5,114,0,
0,471,472,5,111,0,0,472,504,5,119,0,0,473,474,5,92,0,0,474,475,5,
108,0,0,475,476,5,111,0,0,476,477,5,110,0,0,477,478,5,103,0,0,478,
479,5,114,0,0,479,480,5,105,0,0,480,481,5,103,0,0,481,482,5,104,
0,0,482,483,5,116,0,0,483,484,5,97,0,0,484,485,5,114,0,0,485,486,
5,114,0,0,486,487,5,111,0,0,487,504,5,119,0,0,488,489,5,92,0,0,489,
490,5,76,0,0,490,491,5,111,0,0,491,492,5,110,0,0,492,493,5,103,0,
0,493,494,5,114,0,0,494,495,5,105,0,0,495,496,5,103,0,0,496,497,
5,104,0,0,497,498,5,116,0,0,498,499,5,97,0,0,499,500,5,114,0,0,500,
501,5,114,0,0,501,502,5,111,0,0,502,504,5,119,0,0,503,448,1,0,0,
0,503,451,1,0,0,0,503,462,1,0,0,0,503,473,1,0,0,0,503,488,1,0,0,
0,504,66,1,0,0,0,505,506,5,92,0,0,506,507,5,105,0,0,507,508,5,110,
0,0,508,521,5,116,0,0,509,510,5,92,0,0,510,511,5,105,0,0,511,512,
5,110,0,0,512,513,5,116,0,0,513,514,5,92,0,0,514,515,5,108,0,0,515,
516,5,105,0,0,516,517,5,109,0,0,517,518,5,105,0,0,518,519,5,116,
0,0,519,521,5,115,0,0,520,505,1,0,0,0,520,509,1,0,0,0,521,68,1,0,
0,0,522,523,5,92,0,0,523,524,5,115,0,0,524,525,5,117,0,0,525,526,
5,109,0,0,526,70,1,0,0,0,527,528,5,92,0,0,528,529,5,112,0,0,529,
530,5,114,0,0,530,531,5,111,0,0,531,532,5,100,0,0,532,72,1,0,0,0,
533,534,5,92,0,0,534,535,5,101,0,0,535,536,5,120,0,0,536,537,5,112,
0,0,537,74,1,0,0,0,538,539,5,92,0,0,539,540,5,108,0,0,540,541,5,
111,0,0,541,542,5,103,0,0,542,76,1,0,0,0,543,544,5,92,0,0,544,545,
5,108,0,0,545,546,5,103,0,0,546,78,1,0,0,0,547,548,5,92,0,0,548,
549,5,108,0,0,549,550,5,110,0,0,550,80,1,0,0,0,551,552,5,92,0,0,
552,553,5,115,0,0,553,554,5,105,0,0,554,555,5,110,0,0,555,82,1,0,
0,0,556,557,5,92,0,0,557,558,5,99,0,0,558,559,5,111,0,0,559,560,
5,115,0,0,560,84,1,0,0,0,561,562,5,92,0,0,562,563,5,116,0,0,563,
564,5,97,0,0,564,565,5,110,0,0,565,86,1,0,0,0,566,567,5,92,0,0,567,
568,5,99,0,0,568,569,5,115,0,0,569,570,5,99,0,0,570,88,1,0,0,0,571,
572,5,92,0,0,572,573,5,115,0,0,573,574,5,101,0,0,574,575,5,99,0,
0,575,90,1,0,0,0,576,577,5,92,0,0,577,578,5,99,0,0,578,579,5,111,
0,0,579,580,5,116,0,0,580,92,1,0,0,0,581,582,5,92,0,0,582,583,5,
97,0,0,583,584,5,114,0,0,584,585,5,99,0,0,585,586,5,115,0,0,586,
587,5,105,0,0,587,588,5,110,0,0,588,94,1,0,0,0,589,590,5,92,0,0,
590,591,5,97,0,0,591,592,5,114,0,0,592,593,5,99,0,0,593,594,5,99,
0,0,594,595,5,111,0,0,595,596,5,115,0,0,596,96,1,0,0,0,597,598,5,
92,0,0,598,599,5,97,0,0,599,600,5,114,0,0,600,601,5,99,0,0,601,602,
5,116,0,0,602,603,5,97,0,0,603,604,5,110,0,0,604,98,1,0,0,0,605,
606,5,92,0,0,606,607,5,97,0,0,607,608,5,114,0,0,608,609,5,99,0,0,
609,610,5,99,0,0,610,611,5,115,0,0,611,612,5,99,0,0,612,100,1,0,
0,0,613,614,5,92,0,0,614,615,5,97,0,0,615,616,5,114,0,0,616,617,
5,99,0,0,617,618,5,115,0,0,618,619,5,101,0,0,619,620,5,99,0,0,620,
102,1,0,0,0,621,622,5,92,0,0,622,623,5,97,0,0,623,624,5,114,0,0,
624,625,5,99,0,0,625,626,5,99,0,0,626,627,5,111,0,0,627,628,5,116,
0,0,628,104,1,0,0,0,629,630,5,92,0,0,630,631,5,115,0,0,631,632,5,
105,0,0,632,633,5,110,0,0,633,634,5,104,0,0,634,106,1,0,0,0,635,
636,5,92,0,0,636,637,5,99,0,0,637,638,5,111,0,0,638,639,5,115,0,
0,639,640,5,104,0,0,640,108,1,0,0,0,641,642,5,92,0,0,642,643,5,116,
0,0,643,644,5,97,0,0,644,645,5,110,0,0,645,646,5,104,0,0,646,110,
1,0,0,0,647,648,5,92,0,0,648,649,5,97,0,0,649,650,5,114,0,0,650,
651,5,115,0,0,651,652,5,105,0,0,652,653,5,110,0,0,653,654,5,104,
0,0,654,112,1,0,0,0,655,656,5,92,0,0,656,657,5,97,0,0,657,658,5,
114,0,0,658,659,5,99,0,0,659,660,5,111,0,0,660,661,5,115,0,0,661,
662,5,104,0,0,662,114,1,0,0,0,663,664,5,92,0,0,664,665,5,97,0,0,
665,666,5,114,0,0,666,667,5,116,0,0,667,668,5,97,0,0,668,669,5,110,
0,0,669,670,5,104,0,0,670,116,1,0,0,0,671,672,5,92,0,0,672,673,5,
108,0,0,673,674,5,102,0,0,674,675,5,108,0,0,675,676,5,111,0,0,676,
677,5,111,0,0,677,678,5,114,0,0,678,118,1,0,0,0,679,680,5,92,0,0,
680,681,5,114,0,0,681,682,5,102,0,0,682,683,5,108,0,0,683,684,5,
111,0,0,684,685,5,111,0,0,685,686,5,114,0,0,686,120,1,0,0,0,687,
688,5,92,0,0,688,689,5,108,0,0,689,690,5,99,0,0,690,691,5,101,0,
0,691,692,5,105,0,0,692,693,5,108,0,0,693,122,1,0,0,0,694,695,5,
92,0,0,695,696,5,114,0,0,696,697,5,99,0,0,697,698,5,101,0,0,698,
699,5,105,0,0,699,700,5,108,0,0,700,124,1,0,0,0,701,702,5,92,0,0,
702,703,5,115,0,0,703,704,5,113,0,0,704,705,5,114,0,0,705,706,5,
116,0,0,706,126,1,0,0,0,707,708,5,92,0,0,708,709,5,111,0,0,709,710,
5,118,0,0,710,711,5,101,0,0,711,712,5,114,0,0,712,713,5,108,0,0,
713,714,5,105,0,0,714,715,5,110,0,0,715,716,5,101,0,0,716,128,1,
0,0,0,717,718,5,92,0,0,718,719,5,116,0,0,719,720,5,105,0,0,720,721,
5,109,0,0,721,722,5,101,0,0,722,723,5,115,0,0,723,130,1,0,0,0,724,
725,5,92,0,0,725,726,5,99,0,0,726,727,5,100,0,0,727,728,5,111,0,
0,728,729,5,116,0,0,729,132,1,0,0,0,730,731,5,92,0,0,731,732,5,100,
0,0,732,733,5,105,0,0,733,734,5,118,0,0,734,134,1,0,0,0,735,736,
5,92,0,0,736,737,5,102,0,0,737,738,5,114,0,0,738,739,5,97,0,0,739,
753,5,99,0,0,740,741,5,92,0,0,741,742,5,100,0,0,742,743,5,102,0,
0,743,744,5,114,0,0,744,745,5,97,0,0,745,753,5,99,0,0,746,747,5,
92,0,0,747,748,5,116,0,0,748,749,5,102,0,0,749,750,5,114,0,0,750,
751,5,97,0,0,751,753,5,99,0,0,752,735,1,0,0,0,752,740,1,0,0,0,752,
746,1,0,0,0,753,136,1,0,0,0,754,755,5,92,0,0,755,756,5,98,0,0,756,
757,5,105,0,0,757,758,5,110,0,0,758,759,5,111,0,0,759,760,5,109,
0,0,760,138,1,0,0,0,761,762,5,92,0,0,762,763,5,100,0,0,763,764,5,
98,0,0,764,765,5,105,0,0,765,766,5,110,0,0,766,767,5,111,0,0,767,
768,5,109,0,0,768,140,1,0,0,0,769,770,5,92,0,0,770,771,5,116,0,0,
771,772,5,98,0,0,772,773,5,105,0,0,773,774,5,110,0,0,774,775,5,111,
0,0,775,776,5,109,0,0,776,142,1,0,0,0,777,778,5,92,0,0,778,779,5,
109,0,0,779,780,5,97,0,0,780,781,5,116,0,0,781,782,5,104,0,0,782,
783,5,105,0,0,783,784,5,116,0,0,784,144,1,0,0,0,785,786,5,95,0,0,
786,146,1,0,0,0,787,788,5,94,0,0,788,148,1,0,0,0,789,790,5,58,0,
0,790,150,1,0,0,0,791,792,7,0,0,0,792,152,1,0,0,0,793,797,5,100,
0,0,794,796,3,151,75,0,795,794,1,0,0,0,796,799,1,0,0,0,797,798,1,
0,0,0,797,795,1,0,0,0,798,807,1,0,0,0,799,797,1,0,0,0,800,808,7,
1,0,0,801,803,5,92,0,0,802,804,7,1,0,0,803,802,1,0,0,0,804,805,1,
0,0,0,805,803,1,0,0,0,805,806,1,0,0,0,806,808,1,0,0,0,807,800,1,
0,0,0,807,801,1,0,0,0,808,154,1,0,0,0,809,810,7,1,0,0,810,156,1,
0,0,0,811,812,7,2,0,0,812,158,1,0,0,0,813,817,5,38,0,0,814,816,3,
151,75,0,815,814,1,0,0,0,816,819,1,0,0,0,817,818,1,0,0,0,817,815,
1,0,0,0,818,821,1,0,0,0,819,817,1,0,0,0,820,813,1,0,0,0,820,821,
1,0,0,0,821,822,1,0,0,0,822,834,5,61,0,0,823,831,5,61,0,0,824,826,
3,151,75,0,825,824,1,0,0,0,826,829,1,0,0,0,827,828,1,0,0,0,827,825,
1,0,0,0,828,830,1,0,0,0,829,827,1,0,0,0,830,832,5,38,0,0,831,827,
1,0,0,0,831,832,1,0,0,0,832,834,1,0,0,0,833,820,1,0,0,0,833,823,
1,0,0,0,834,160,1,0,0,0,835,836,5,92,0,0,836,837,5,110,0,0,837,838,
5,101,0,0,838,839,5,113,0,0,839,162,1,0,0,0,840,841,5,60,0,0,841,
164,1,0,0,0,842,843,5,92,0,0,843,844,5,108,0,0,844,845,5,101,0,0,
845,852,5,113,0,0,846,847,5,92,0,0,847,848,5,108,0,0,848,852,5,101,
0,0,849,852,3,167,83,0,850,852,3,169,84,0,851,842,1,0,0,0,851,846,
1,0,0,0,851,849,1,0,0,0,851,850,1,0,0,0,852,166,1,0,0,0,853,854,
5,92,0,0,854,855,5,108,0,0,855,856,5,101,0,0,856,857,5,113,0,0,857,
858,5,113,0,0,858,168,1,0,0,0,859,860,5,92,0,0,860,861,5,108,0,0,
861,862,5,101,0,0,862,863,5,113,0,0,863,864,5,115,0,0,864,865,5,
108,0,0,865,866,5,97,0,0,866,867,5,110,0,0,867,868,5,116,0,0,868,
170,1,0,0,0,869,870,5,62,0,0,870,172,1,0,0,0,871,872,5,92,0,0,872,
873,5,103,0,0,873,874,5,101,0,0,874,881,5,113,0,0,875,876,5,92,0,
0,876,877,5,103,0,0,877,881,5,101,0,0,878,881,3,175,87,0,879,881,
3,177,88,0,880,871,1,0,0,0,880,875,1,0,0,0,880,878,1,0,0,0,880,879,
1,0,0,0,881,174,1,0,0,0,882,883,5,92,0,0,883,884,5,103,0,0,884,885,
5,101,0,0,885,886,5,113,0,0,886,887,5,113,0,0,887,176,1,0,0,0,888,
889,5,92,0,0,889,890,5,103,0,0,890,891,5,101,0,0,891,892,5,113,0,
0,892,893,5,115,0,0,893,894,5,108,0,0,894,895,5,97,0,0,895,896,5,
110,0,0,896,897,5,116,0,0,897,178,1,0,0,0,898,899,5,33,0,0,899,180,
1,0,0,0,900,902,5,39,0,0,901,900,1,0,0,0,902,903,1,0,0,0,903,901,
1,0,0,0,903,904,1,0,0,0,904,182,1,0,0,0,905,907,5,92,0,0,906,908,
7,1,0,0,907,906,1,0,0,0,908,909,1,0,0,0,909,907,1,0,0,0,909,910,
1,0,0,0,910,184,1,0,0,0,22,0,192,208,223,240,276,380,503,520,752,
797,805,807,817,820,827,831,833,851,880,903,909,1,6,0,0
]
class LaTeXLexer(Lexer):
atn = ATNDeserializer().deserialize(serializedATN())
decisionsToDFA = [ DFA(ds, i) for i, ds in enumerate(atn.decisionToState) ]
T__0 = 1
T__1 = 2
WS = 3
THINSPACE = 4
MEDSPACE = 5
THICKSPACE = 6
QUAD = 7
QQUAD = 8
NEGTHINSPACE = 9
NEGMEDSPACE = 10
NEGTHICKSPACE = 11
CMD_LEFT = 12
CMD_RIGHT = 13
IGNORE = 14
ADD = 15
SUB = 16
MUL = 17
DIV = 18
L_PAREN = 19
R_PAREN = 20
L_BRACE = 21
R_BRACE = 22
L_BRACE_LITERAL = 23
R_BRACE_LITERAL = 24
L_BRACKET = 25
R_BRACKET = 26
BAR = 27
R_BAR = 28
L_BAR = 29
L_ANGLE = 30
R_ANGLE = 31
FUNC_LIM = 32
LIM_APPROACH_SYM = 33
FUNC_INT = 34
FUNC_SUM = 35
FUNC_PROD = 36
FUNC_EXP = 37
FUNC_LOG = 38
FUNC_LG = 39
FUNC_LN = 40
FUNC_SIN = 41
FUNC_COS = 42
FUNC_TAN = 43
FUNC_CSC = 44
FUNC_SEC = 45
FUNC_COT = 46
FUNC_ARCSIN = 47
FUNC_ARCCOS = 48
FUNC_ARCTAN = 49
FUNC_ARCCSC = 50
FUNC_ARCSEC = 51
FUNC_ARCCOT = 52
FUNC_SINH = 53
FUNC_COSH = 54
FUNC_TANH = 55
FUNC_ARSINH = 56
FUNC_ARCOSH = 57
FUNC_ARTANH = 58
L_FLOOR = 59
R_FLOOR = 60
L_CEIL = 61
R_CEIL = 62
FUNC_SQRT = 63
FUNC_OVERLINE = 64
CMD_TIMES = 65
CMD_CDOT = 66
CMD_DIV = 67
CMD_FRAC = 68
CMD_BINOM = 69
CMD_DBINOM = 70
CMD_TBINOM = 71
CMD_MATHIT = 72
UNDERSCORE = 73
CARET = 74
COLON = 75
DIFFERENTIAL = 76
LETTER = 77
DIGIT = 78
EQUAL = 79
NEQ = 80
LT = 81
LTE = 82
LTE_Q = 83
LTE_S = 84
GT = 85
GTE = 86
GTE_Q = 87
GTE_S = 88
BANG = 89
SINGLE_QUOTES = 90
SYMBOL = 91
channelNames = [ u"DEFAULT_TOKEN_CHANNEL", u"HIDDEN" ]
modeNames = [ "DEFAULT_MODE" ]
literalNames = [ "<INVALID>",
"','", "'.'", "'\\quad'", "'\\qquad'", "'\\negmedspace'", "'\\negthickspace'",
"'\\left'", "'\\right'", "'+'", "'-'", "'*'", "'/'", "'('",
"')'", "'{'", "'}'", "'\\{'", "'\\}'", "'['", "']'", "'|'",
"'\\right|'", "'\\left|'", "'\\langle'", "'\\rangle'", "'\\lim'",
"'\\sum'", "'\\prod'", "'\\exp'", "'\\log'", "'\\lg'", "'\\ln'",
"'\\sin'", "'\\cos'", "'\\tan'", "'\\csc'", "'\\sec'", "'\\cot'",
"'\\arcsin'", "'\\arccos'", "'\\arctan'", "'\\arccsc'", "'\\arcsec'",
"'\\arccot'", "'\\sinh'", "'\\cosh'", "'\\tanh'", "'\\arsinh'",
"'\\arcosh'", "'\\artanh'", "'\\lfloor'", "'\\rfloor'", "'\\lceil'",
"'\\rceil'", "'\\sqrt'", "'\\overline'", "'\\times'", "'\\cdot'",
"'\\div'", "'\\binom'", "'\\dbinom'", "'\\tbinom'", "'\\mathit'",
"'_'", "'^'", "':'", "'\\neq'", "'<'", "'\\leqq'", "'\\leqslant'",
"'>'", "'\\geqq'", "'\\geqslant'", "'!'" ]
symbolicNames = [ "<INVALID>",
"WS", "THINSPACE", "MEDSPACE", "THICKSPACE", "QUAD", "QQUAD",
"NEGTHINSPACE", "NEGMEDSPACE", "NEGTHICKSPACE", "CMD_LEFT",
"CMD_RIGHT", "IGNORE", "ADD", "SUB", "MUL", "DIV", "L_PAREN",
"R_PAREN", "L_BRACE", "R_BRACE", "L_BRACE_LITERAL", "R_BRACE_LITERAL",
"L_BRACKET", "R_BRACKET", "BAR", "R_BAR", "L_BAR", "L_ANGLE",
"R_ANGLE", "FUNC_LIM", "LIM_APPROACH_SYM", "FUNC_INT", "FUNC_SUM",
"FUNC_PROD", "FUNC_EXP", "FUNC_LOG", "FUNC_LG", "FUNC_LN", "FUNC_SIN",
"FUNC_COS", "FUNC_TAN", "FUNC_CSC", "FUNC_SEC", "FUNC_COT",
"FUNC_ARCSIN", "FUNC_ARCCOS", "FUNC_ARCTAN", "FUNC_ARCCSC",
"FUNC_ARCSEC", "FUNC_ARCCOT", "FUNC_SINH", "FUNC_COSH", "FUNC_TANH",
"FUNC_ARSINH", "FUNC_ARCOSH", "FUNC_ARTANH", "L_FLOOR", "R_FLOOR",
"L_CEIL", "R_CEIL", "FUNC_SQRT", "FUNC_OVERLINE", "CMD_TIMES",
"CMD_CDOT", "CMD_DIV", "CMD_FRAC", "CMD_BINOM", "CMD_DBINOM",
"CMD_TBINOM", "CMD_MATHIT", "UNDERSCORE", "CARET", "COLON",
"DIFFERENTIAL", "LETTER", "DIGIT", "EQUAL", "NEQ", "LT", "LTE",
"LTE_Q", "LTE_S", "GT", "GTE", "GTE_Q", "GTE_S", "BANG", "SINGLE_QUOTES",
"SYMBOL" ]
ruleNames = [ "T__0", "T__1", "WS", "THINSPACE", "MEDSPACE", "THICKSPACE",
"QUAD", "QQUAD", "NEGTHINSPACE", "NEGMEDSPACE", "NEGTHICKSPACE",
"CMD_LEFT", "CMD_RIGHT", "IGNORE", "ADD", "SUB", "MUL",
"DIV", "L_PAREN", "R_PAREN", "L_BRACE", "R_BRACE", "L_BRACE_LITERAL",
"R_BRACE_LITERAL", "L_BRACKET", "R_BRACKET", "BAR", "R_BAR",
"L_BAR", "L_ANGLE", "R_ANGLE", "FUNC_LIM", "LIM_APPROACH_SYM",
"FUNC_INT", "FUNC_SUM", "FUNC_PROD", "FUNC_EXP", "FUNC_LOG",
"FUNC_LG", "FUNC_LN", "FUNC_SIN", "FUNC_COS", "FUNC_TAN",
"FUNC_CSC", "FUNC_SEC", "FUNC_COT", "FUNC_ARCSIN", "FUNC_ARCCOS",
"FUNC_ARCTAN", "FUNC_ARCCSC", "FUNC_ARCSEC", "FUNC_ARCCOT",
"FUNC_SINH", "FUNC_COSH", "FUNC_TANH", "FUNC_ARSINH",
"FUNC_ARCOSH", "FUNC_ARTANH", "L_FLOOR", "R_FLOOR", "L_CEIL",
"R_CEIL", "FUNC_SQRT", "FUNC_OVERLINE", "CMD_TIMES", "CMD_CDOT",
"CMD_DIV", "CMD_FRAC", "CMD_BINOM", "CMD_DBINOM", "CMD_TBINOM",
"CMD_MATHIT", "UNDERSCORE", "CARET", "COLON", "WS_CHAR",
"DIFFERENTIAL", "LETTER", "DIGIT", "EQUAL", "NEQ", "LT",
"LTE", "LTE_Q", "LTE_S", "GT", "GTE", "GTE_Q", "GTE_S",
"BANG", "SINGLE_QUOTES", "SYMBOL" ]
grammarFileName = "LaTeX.g4"
def __init__(self, input=None, output:TextIO = sys.stdout):
super().__init__(input, output)
self.checkVersion("4.11.1")
self._interp = LexerATNSimulator(self, self.atn, self.decisionsToDFA, PredictionContextCache())
self._actions = None
self._predicates = None
PK ]ZZZN� �� � ) sympy/parsing/latex/_antlr/latexparser.py# *** GENERATED BY `setup.py antlr`, DO NOT EDIT BY HAND ***
#
# Generated from ../LaTeX.g4, derived from latex2sympy
# latex2sympy is licensed under the MIT license
# https://github.com/augustt198/latex2sympy/blob/master/LICENSE.txt
#
# Generated with antlr4
# antlr4 is licensed under the BSD-3-Clause License
# https://github.com/antlr/antlr4/blob/master/LICENSE.txt
from antlr4 import *
from io import StringIO
import sys
if sys.version_info[1] > 5:
from typing import TextIO
else:
from typing.io import TextIO
def serializedATN():
return [
4,1,91,522,2,0,7,0,2,1,7,1,2,2,7,2,2,3,7,3,2,4,7,4,2,5,7,5,2,6,7,
6,2,7,7,7,2,8,7,8,2,9,7,9,2,10,7,10,2,11,7,11,2,12,7,12,2,13,7,13,
2,14,7,14,2,15,7,15,2,16,7,16,2,17,7,17,2,18,7,18,2,19,7,19,2,20,
7,20,2,21,7,21,2,22,7,22,2,23,7,23,2,24,7,24,2,25,7,25,2,26,7,26,
2,27,7,27,2,28,7,28,2,29,7,29,2,30,7,30,2,31,7,31,2,32,7,32,2,33,
7,33,2,34,7,34,2,35,7,35,2,36,7,36,2,37,7,37,2,38,7,38,2,39,7,39,
2,40,7,40,1,0,1,0,1,1,1,1,1,1,1,1,1,1,1,1,5,1,91,8,1,10,1,12,1,94,
9,1,1,2,1,2,1,2,1,2,1,3,1,3,1,4,1,4,1,4,1,4,1,4,1,4,5,4,108,8,4,
10,4,12,4,111,9,4,1,5,1,5,1,5,1,5,1,5,1,5,5,5,119,8,5,10,5,12,5,
122,9,5,1,6,1,6,1,6,1,6,1,6,1,6,5,6,130,8,6,10,6,12,6,133,9,6,1,
7,1,7,1,7,4,7,138,8,7,11,7,12,7,139,3,7,142,8,7,1,8,1,8,1,8,1,8,
5,8,148,8,8,10,8,12,8,151,9,8,3,8,153,8,8,1,9,1,9,5,9,157,8,9,10,
9,12,9,160,9,9,1,10,1,10,5,10,164,8,10,10,10,12,10,167,9,10,1,11,
1,11,3,11,171,8,11,1,12,1,12,1,12,1,12,1,12,1,12,3,12,179,8,12,1,
13,1,13,1,13,1,13,3,13,185,8,13,1,13,1,13,1,14,1,14,1,14,1,14,3,
14,193,8,14,1,14,1,14,1,15,1,15,1,15,1,15,1,15,1,15,1,15,1,15,1,
15,1,15,3,15,207,8,15,1,15,3,15,210,8,15,5,15,212,8,15,10,15,12,
15,215,9,15,1,16,1,16,1,16,1,16,1,16,1,16,1,16,1,16,1,16,1,16,3,
16,227,8,16,1,16,3,16,230,8,16,5,16,232,8,16,10,16,12,16,235,9,16,
1,17,1,17,1,17,1,17,1,17,1,17,3,17,243,8,17,1,18,1,18,1,18,1,18,
1,18,3,18,250,8,18,1,19,1,19,1,19,1,19,1,19,1,19,1,19,1,19,1,19,
1,19,1,19,1,19,1,19,1,19,1,19,1,19,3,19,268,8,19,1,20,1,20,1,20,
1,20,1,21,4,21,275,8,21,11,21,12,21,276,1,21,1,21,1,21,1,21,5,21,
283,8,21,10,21,12,21,286,9,21,1,21,1,21,4,21,290,8,21,11,21,12,21,
291,3,21,294,8,21,1,22,1,22,3,22,298,8,22,1,22,3,22,301,8,22,1,22,
3,22,304,8,22,1,22,3,22,307,8,22,3,22,309,8,22,1,22,1,22,1,22,1,
22,1,22,1,22,1,22,3,22,318,8,22,1,23,1,23,1,23,1,23,1,24,1,24,1,
24,1,24,1,25,1,25,1,25,1,25,1,25,1,26,5,26,334,8,26,10,26,12,26,
337,9,26,1,27,1,27,1,27,1,27,1,27,1,27,3,27,345,8,27,1,27,1,27,1,
27,1,27,1,27,3,27,352,8,27,1,28,1,28,1,28,1,28,1,28,1,28,1,28,1,
28,1,29,1,29,1,29,1,29,1,30,1,30,1,30,1,30,1,31,1,31,1,32,1,32,3,
32,374,8,32,1,32,3,32,377,8,32,1,32,3,32,380,8,32,1,32,3,32,383,
8,32,3,32,385,8,32,1,32,1,32,1,32,1,32,1,32,3,32,392,8,32,1,32,1,
32,3,32,396,8,32,1,32,3,32,399,8,32,1,32,3,32,402,8,32,1,32,3,32,
405,8,32,3,32,407,8,32,1,32,1,32,1,32,1,32,1,32,1,32,1,32,1,32,1,
32,1,32,1,32,3,32,420,8,32,1,32,3,32,423,8,32,1,32,1,32,1,32,3,32,
428,8,32,1,32,1,32,1,32,1,32,1,32,3,32,435,8,32,1,32,1,32,1,32,1,
32,1,32,1,32,1,32,1,32,1,32,1,32,1,32,1,32,1,32,1,32,1,32,1,32,3,
32,453,8,32,1,32,1,32,1,32,1,32,1,32,1,32,3,32,461,8,32,1,33,1,33,
1,33,1,33,1,33,3,33,468,8,33,1,34,1,34,1,34,1,34,1,34,1,34,1,34,
1,34,1,34,1,34,1,34,3,34,481,8,34,3,34,483,8,34,1,34,1,34,1,35,1,
35,1,35,1,35,1,35,3,35,492,8,35,1,36,1,36,1,37,1,37,1,37,1,37,1,
37,1,37,3,37,502,8,37,1,38,1,38,1,38,1,38,1,38,1,38,3,38,510,8,38,
1,39,1,39,1,39,1,39,1,39,1,40,1,40,1,40,1,40,1,40,1,40,0,6,2,8,10,
12,30,32,41,0,2,4,6,8,10,12,14,16,18,20,22,24,26,28,30,32,34,36,
38,40,42,44,46,48,50,52,54,56,58,60,62,64,66,68,70,72,74,76,78,80,
0,9,2,0,79,82,85,86,1,0,15,16,3,0,17,18,65,67,75,75,2,0,77,77,91,
91,1,0,27,28,2,0,27,27,29,29,1,0,69,71,1,0,37,58,1,0,35,36,563,0,
82,1,0,0,0,2,84,1,0,0,0,4,95,1,0,0,0,6,99,1,0,0,0,8,101,1,0,0,0,
10,112,1,0,0,0,12,123,1,0,0,0,14,141,1,0,0,0,16,152,1,0,0,0,18,154,
1,0,0,0,20,161,1,0,0,0,22,170,1,0,0,0,24,172,1,0,0,0,26,180,1,0,
0,0,28,188,1,0,0,0,30,196,1,0,0,0,32,216,1,0,0,0,34,242,1,0,0,0,
36,249,1,0,0,0,38,267,1,0,0,0,40,269,1,0,0,0,42,274,1,0,0,0,44,317,
1,0,0,0,46,319,1,0,0,0,48,323,1,0,0,0,50,327,1,0,0,0,52,335,1,0,
0,0,54,338,1,0,0,0,56,353,1,0,0,0,58,361,1,0,0,0,60,365,1,0,0,0,
62,369,1,0,0,0,64,460,1,0,0,0,66,467,1,0,0,0,68,469,1,0,0,0,70,491,
1,0,0,0,72,493,1,0,0,0,74,495,1,0,0,0,76,503,1,0,0,0,78,511,1,0,
0,0,80,516,1,0,0,0,82,83,3,2,1,0,83,1,1,0,0,0,84,85,6,1,-1,0,85,
86,3,6,3,0,86,92,1,0,0,0,87,88,10,2,0,0,88,89,7,0,0,0,89,91,3,2,
1,3,90,87,1,0,0,0,91,94,1,0,0,0,92,90,1,0,0,0,92,93,1,0,0,0,93,3,
1,0,0,0,94,92,1,0,0,0,95,96,3,6,3,0,96,97,5,79,0,0,97,98,3,6,3,0,
98,5,1,0,0,0,99,100,3,8,4,0,100,7,1,0,0,0,101,102,6,4,-1,0,102,103,
3,10,5,0,103,109,1,0,0,0,104,105,10,2,0,0,105,106,7,1,0,0,106,108,
3,8,4,3,107,104,1,0,0,0,108,111,1,0,0,0,109,107,1,0,0,0,109,110,
1,0,0,0,110,9,1,0,0,0,111,109,1,0,0,0,112,113,6,5,-1,0,113,114,3,
14,7,0,114,120,1,0,0,0,115,116,10,2,0,0,116,117,7,2,0,0,117,119,
3,10,5,3,118,115,1,0,0,0,119,122,1,0,0,0,120,118,1,0,0,0,120,121,
1,0,0,0,121,11,1,0,0,0,122,120,1,0,0,0,123,124,6,6,-1,0,124,125,
3,16,8,0,125,131,1,0,0,0,126,127,10,2,0,0,127,128,7,2,0,0,128,130,
3,12,6,3,129,126,1,0,0,0,130,133,1,0,0,0,131,129,1,0,0,0,131,132,
1,0,0,0,132,13,1,0,0,0,133,131,1,0,0,0,134,135,7,1,0,0,135,142,3,
14,7,0,136,138,3,18,9,0,137,136,1,0,0,0,138,139,1,0,0,0,139,137,
1,0,0,0,139,140,1,0,0,0,140,142,1,0,0,0,141,134,1,0,0,0,141,137,
1,0,0,0,142,15,1,0,0,0,143,144,7,1,0,0,144,153,3,16,8,0,145,149,
3,18,9,0,146,148,3,20,10,0,147,146,1,0,0,0,148,151,1,0,0,0,149,147,
1,0,0,0,149,150,1,0,0,0,150,153,1,0,0,0,151,149,1,0,0,0,152,143,
1,0,0,0,152,145,1,0,0,0,153,17,1,0,0,0,154,158,3,30,15,0,155,157,
3,22,11,0,156,155,1,0,0,0,157,160,1,0,0,0,158,156,1,0,0,0,158,159,
1,0,0,0,159,19,1,0,0,0,160,158,1,0,0,0,161,165,3,32,16,0,162,164,
3,22,11,0,163,162,1,0,0,0,164,167,1,0,0,0,165,163,1,0,0,0,165,166,
1,0,0,0,166,21,1,0,0,0,167,165,1,0,0,0,168,171,5,89,0,0,169,171,
3,24,12,0,170,168,1,0,0,0,170,169,1,0,0,0,171,23,1,0,0,0,172,178,
5,27,0,0,173,179,3,28,14,0,174,179,3,26,13,0,175,176,3,28,14,0,176,
177,3,26,13,0,177,179,1,0,0,0,178,173,1,0,0,0,178,174,1,0,0,0,178,
175,1,0,0,0,179,25,1,0,0,0,180,181,5,73,0,0,181,184,5,21,0,0,182,
185,3,6,3,0,183,185,3,4,2,0,184,182,1,0,0,0,184,183,1,0,0,0,185,
186,1,0,0,0,186,187,5,22,0,0,187,27,1,0,0,0,188,189,5,74,0,0,189,
192,5,21,0,0,190,193,3,6,3,0,191,193,3,4,2,0,192,190,1,0,0,0,192,
191,1,0,0,0,193,194,1,0,0,0,194,195,5,22,0,0,195,29,1,0,0,0,196,
197,6,15,-1,0,197,198,3,34,17,0,198,213,1,0,0,0,199,200,10,2,0,0,
200,206,5,74,0,0,201,207,3,44,22,0,202,203,5,21,0,0,203,204,3,6,
3,0,204,205,5,22,0,0,205,207,1,0,0,0,206,201,1,0,0,0,206,202,1,0,
0,0,207,209,1,0,0,0,208,210,3,74,37,0,209,208,1,0,0,0,209,210,1,
0,0,0,210,212,1,0,0,0,211,199,1,0,0,0,212,215,1,0,0,0,213,211,1,
0,0,0,213,214,1,0,0,0,214,31,1,0,0,0,215,213,1,0,0,0,216,217,6,16,
-1,0,217,218,3,36,18,0,218,233,1,0,0,0,219,220,10,2,0,0,220,226,
5,74,0,0,221,227,3,44,22,0,222,223,5,21,0,0,223,224,3,6,3,0,224,
225,5,22,0,0,225,227,1,0,0,0,226,221,1,0,0,0,226,222,1,0,0,0,227,
229,1,0,0,0,228,230,3,74,37,0,229,228,1,0,0,0,229,230,1,0,0,0,230,
232,1,0,0,0,231,219,1,0,0,0,232,235,1,0,0,0,233,231,1,0,0,0,233,
234,1,0,0,0,234,33,1,0,0,0,235,233,1,0,0,0,236,243,3,38,19,0,237,
243,3,40,20,0,238,243,3,64,32,0,239,243,3,44,22,0,240,243,3,58,29,
0,241,243,3,60,30,0,242,236,1,0,0,0,242,237,1,0,0,0,242,238,1,0,
0,0,242,239,1,0,0,0,242,240,1,0,0,0,242,241,1,0,0,0,243,35,1,0,0,
0,244,250,3,38,19,0,245,250,3,40,20,0,246,250,3,44,22,0,247,250,
3,58,29,0,248,250,3,60,30,0,249,244,1,0,0,0,249,245,1,0,0,0,249,
246,1,0,0,0,249,247,1,0,0,0,249,248,1,0,0,0,250,37,1,0,0,0,251,252,
5,19,0,0,252,253,3,6,3,0,253,254,5,20,0,0,254,268,1,0,0,0,255,256,
5,25,0,0,256,257,3,6,3,0,257,258,5,26,0,0,258,268,1,0,0,0,259,260,
5,21,0,0,260,261,3,6,3,0,261,262,5,22,0,0,262,268,1,0,0,0,263,264,
5,23,0,0,264,265,3,6,3,0,265,266,5,24,0,0,266,268,1,0,0,0,267,251,
1,0,0,0,267,255,1,0,0,0,267,259,1,0,0,0,267,263,1,0,0,0,268,39,1,
0,0,0,269,270,5,27,0,0,270,271,3,6,3,0,271,272,5,27,0,0,272,41,1,
0,0,0,273,275,5,78,0,0,274,273,1,0,0,0,275,276,1,0,0,0,276,274,1,
0,0,0,276,277,1,0,0,0,277,284,1,0,0,0,278,279,5,1,0,0,279,280,5,
78,0,0,280,281,5,78,0,0,281,283,5,78,0,0,282,278,1,0,0,0,283,286,
1,0,0,0,284,282,1,0,0,0,284,285,1,0,0,0,285,293,1,0,0,0,286,284,
1,0,0,0,287,289,5,2,0,0,288,290,5,78,0,0,289,288,1,0,0,0,290,291,
1,0,0,0,291,289,1,0,0,0,291,292,1,0,0,0,292,294,1,0,0,0,293,287,
1,0,0,0,293,294,1,0,0,0,294,43,1,0,0,0,295,308,7,3,0,0,296,298,3,
74,37,0,297,296,1,0,0,0,297,298,1,0,0,0,298,300,1,0,0,0,299,301,
5,90,0,0,300,299,1,0,0,0,300,301,1,0,0,0,301,309,1,0,0,0,302,304,
5,90,0,0,303,302,1,0,0,0,303,304,1,0,0,0,304,306,1,0,0,0,305,307,
3,74,37,0,306,305,1,0,0,0,306,307,1,0,0,0,307,309,1,0,0,0,308,297,
1,0,0,0,308,303,1,0,0,0,309,318,1,0,0,0,310,318,3,42,21,0,311,318,
5,76,0,0,312,318,3,50,25,0,313,318,3,54,27,0,314,318,3,56,28,0,315,
318,3,46,23,0,316,318,3,48,24,0,317,295,1,0,0,0,317,310,1,0,0,0,
317,311,1,0,0,0,317,312,1,0,0,0,317,313,1,0,0,0,317,314,1,0,0,0,
317,315,1,0,0,0,317,316,1,0,0,0,318,45,1,0,0,0,319,320,5,30,0,0,
320,321,3,6,3,0,321,322,7,4,0,0,322,47,1,0,0,0,323,324,7,5,0,0,324,
325,3,6,3,0,325,326,5,31,0,0,326,49,1,0,0,0,327,328,5,72,0,0,328,
329,5,21,0,0,329,330,3,52,26,0,330,331,5,22,0,0,331,51,1,0,0,0,332,
334,5,77,0,0,333,332,1,0,0,0,334,337,1,0,0,0,335,333,1,0,0,0,335,
336,1,0,0,0,336,53,1,0,0,0,337,335,1,0,0,0,338,344,5,68,0,0,339,
345,5,78,0,0,340,341,5,21,0,0,341,342,3,6,3,0,342,343,5,22,0,0,343,
345,1,0,0,0,344,339,1,0,0,0,344,340,1,0,0,0,345,351,1,0,0,0,346,
352,5,78,0,0,347,348,5,21,0,0,348,349,3,6,3,0,349,350,5,22,0,0,350,
352,1,0,0,0,351,346,1,0,0,0,351,347,1,0,0,0,352,55,1,0,0,0,353,354,
7,6,0,0,354,355,5,21,0,0,355,356,3,6,3,0,356,357,5,22,0,0,357,358,
5,21,0,0,358,359,3,6,3,0,359,360,5,22,0,0,360,57,1,0,0,0,361,362,
5,59,0,0,362,363,3,6,3,0,363,364,5,60,0,0,364,59,1,0,0,0,365,366,
5,61,0,0,366,367,3,6,3,0,367,368,5,62,0,0,368,61,1,0,0,0,369,370,
7,7,0,0,370,63,1,0,0,0,371,384,3,62,31,0,372,374,3,74,37,0,373,372,
1,0,0,0,373,374,1,0,0,0,374,376,1,0,0,0,375,377,3,76,38,0,376,375,
1,0,0,0,376,377,1,0,0,0,377,385,1,0,0,0,378,380,3,76,38,0,379,378,
1,0,0,0,379,380,1,0,0,0,380,382,1,0,0,0,381,383,3,74,37,0,382,381,
1,0,0,0,382,383,1,0,0,0,383,385,1,0,0,0,384,373,1,0,0,0,384,379,
1,0,0,0,385,391,1,0,0,0,386,387,5,19,0,0,387,388,3,70,35,0,388,389,
5,20,0,0,389,392,1,0,0,0,390,392,3,72,36,0,391,386,1,0,0,0,391,390,
1,0,0,0,392,461,1,0,0,0,393,406,7,3,0,0,394,396,3,74,37,0,395,394,
1,0,0,0,395,396,1,0,0,0,396,398,1,0,0,0,397,399,5,90,0,0,398,397,
1,0,0,0,398,399,1,0,0,0,399,407,1,0,0,0,400,402,5,90,0,0,401,400,
1,0,0,0,401,402,1,0,0,0,402,404,1,0,0,0,403,405,3,74,37,0,404,403,
1,0,0,0,404,405,1,0,0,0,405,407,1,0,0,0,406,395,1,0,0,0,406,401,
1,0,0,0,407,408,1,0,0,0,408,409,5,19,0,0,409,410,3,66,33,0,410,411,
5,20,0,0,411,461,1,0,0,0,412,419,5,34,0,0,413,414,3,74,37,0,414,
415,3,76,38,0,415,420,1,0,0,0,416,417,3,76,38,0,417,418,3,74,37,
0,418,420,1,0,0,0,419,413,1,0,0,0,419,416,1,0,0,0,419,420,1,0,0,
0,420,427,1,0,0,0,421,423,3,8,4,0,422,421,1,0,0,0,422,423,1,0,0,
0,423,424,1,0,0,0,424,428,5,76,0,0,425,428,3,54,27,0,426,428,3,8,
4,0,427,422,1,0,0,0,427,425,1,0,0,0,427,426,1,0,0,0,428,461,1,0,
0,0,429,434,5,63,0,0,430,431,5,25,0,0,431,432,3,6,3,0,432,433,5,
26,0,0,433,435,1,0,0,0,434,430,1,0,0,0,434,435,1,0,0,0,435,436,1,
0,0,0,436,437,5,21,0,0,437,438,3,6,3,0,438,439,5,22,0,0,439,461,
1,0,0,0,440,441,5,64,0,0,441,442,5,21,0,0,442,443,3,6,3,0,443,444,
5,22,0,0,444,461,1,0,0,0,445,452,7,8,0,0,446,447,3,78,39,0,447,448,
3,76,38,0,448,453,1,0,0,0,449,450,3,76,38,0,450,451,3,78,39,0,451,
453,1,0,0,0,452,446,1,0,0,0,452,449,1,0,0,0,453,454,1,0,0,0,454,
455,3,10,5,0,455,461,1,0,0,0,456,457,5,32,0,0,457,458,3,68,34,0,
458,459,3,10,5,0,459,461,1,0,0,0,460,371,1,0,0,0,460,393,1,0,0,0,
460,412,1,0,0,0,460,429,1,0,0,0,460,440,1,0,0,0,460,445,1,0,0,0,
460,456,1,0,0,0,461,65,1,0,0,0,462,463,3,6,3,0,463,464,5,1,0,0,464,
465,3,66,33,0,465,468,1,0,0,0,466,468,3,6,3,0,467,462,1,0,0,0,467,
466,1,0,0,0,468,67,1,0,0,0,469,470,5,73,0,0,470,471,5,21,0,0,471,
472,7,3,0,0,472,473,5,33,0,0,473,482,3,6,3,0,474,480,5,74,0,0,475,
476,5,21,0,0,476,477,7,1,0,0,477,481,5,22,0,0,478,481,5,15,0,0,479,
481,5,16,0,0,480,475,1,0,0,0,480,478,1,0,0,0,480,479,1,0,0,0,481,
483,1,0,0,0,482,474,1,0,0,0,482,483,1,0,0,0,483,484,1,0,0,0,484,
485,5,22,0,0,485,69,1,0,0,0,486,492,3,6,3,0,487,488,3,6,3,0,488,
489,5,1,0,0,489,490,3,70,35,0,490,492,1,0,0,0,491,486,1,0,0,0,491,
487,1,0,0,0,492,71,1,0,0,0,493,494,3,12,6,0,494,73,1,0,0,0,495,501,
5,73,0,0,496,502,3,44,22,0,497,498,5,21,0,0,498,499,3,6,3,0,499,
500,5,22,0,0,500,502,1,0,0,0,501,496,1,0,0,0,501,497,1,0,0,0,502,
75,1,0,0,0,503,509,5,74,0,0,504,510,3,44,22,0,505,506,5,21,0,0,506,
507,3,6,3,0,507,508,5,22,0,0,508,510,1,0,0,0,509,504,1,0,0,0,509,
505,1,0,0,0,510,77,1,0,0,0,511,512,5,73,0,0,512,513,5,21,0,0,513,
514,3,4,2,0,514,515,5,22,0,0,515,79,1,0,0,0,516,517,5,73,0,0,517,
518,5,21,0,0,518,519,3,4,2,0,519,520,5,22,0,0,520,81,1,0,0,0,59,
92,109,120,131,139,141,149,152,158,165,170,178,184,192,206,209,213,
226,229,233,242,249,267,276,284,291,293,297,300,303,306,308,317,
335,344,351,373,376,379,382,384,391,395,398,401,404,406,419,422,
427,434,452,460,467,480,482,491,501,509
]
class LaTeXParser ( Parser ):
grammarFileName = "LaTeX.g4"
atn = ATNDeserializer().deserialize(serializedATN())
decisionsToDFA = [ DFA(ds, i) for i, ds in enumerate(atn.decisionToState) ]
sharedContextCache = PredictionContextCache()
literalNames = [ "<INVALID>", "','", "'.'", "<INVALID>", "<INVALID>",
"<INVALID>", "<INVALID>", "'\\quad'", "'\\qquad'",
"<INVALID>", "'\\negmedspace'", "'\\negthickspace'",
"'\\left'", "'\\right'", "<INVALID>", "'+'", "'-'",
"'*'", "'/'", "'('", "')'", "'{'", "'}'", "'\\{'",
"'\\}'", "'['", "']'", "'|'", "'\\right|'", "'\\left|'",
"'\\langle'", "'\\rangle'", "'\\lim'", "<INVALID>",
"<INVALID>", "'\\sum'", "'\\prod'", "'\\exp'", "'\\log'",
"'\\lg'", "'\\ln'", "'\\sin'", "'\\cos'", "'\\tan'",
"'\\csc'", "'\\sec'", "'\\cot'", "'\\arcsin'", "'\\arccos'",
"'\\arctan'", "'\\arccsc'", "'\\arcsec'", "'\\arccot'",
"'\\sinh'", "'\\cosh'", "'\\tanh'", "'\\arsinh'", "'\\arcosh'",
"'\\artanh'", "'\\lfloor'", "'\\rfloor'", "'\\lceil'",
"'\\rceil'", "'\\sqrt'", "'\\overline'", "'\\times'",
"'\\cdot'", "'\\div'", "<INVALID>", "'\\binom'", "'\\dbinom'",
"'\\tbinom'", "'\\mathit'", "'_'", "'^'", "':'", "<INVALID>",
"<INVALID>", "<INVALID>", "<INVALID>", "'\\neq'", "'<'",
"<INVALID>", "'\\leqq'", "'\\leqslant'", "'>'", "<INVALID>",
"'\\geqq'", "'\\geqslant'", "'!'" ]
symbolicNames = [ "<INVALID>", "<INVALID>", "<INVALID>", "WS", "THINSPACE",
"MEDSPACE", "THICKSPACE", "QUAD", "QQUAD", "NEGTHINSPACE",
"NEGMEDSPACE", "NEGTHICKSPACE", "CMD_LEFT", "CMD_RIGHT",
"IGNORE", "ADD", "SUB", "MUL", "DIV", "L_PAREN", "R_PAREN",
"L_BRACE", "R_BRACE", "L_BRACE_LITERAL", "R_BRACE_LITERAL",
"L_BRACKET", "R_BRACKET", "BAR", "R_BAR", "L_BAR",
"L_ANGLE", "R_ANGLE", "FUNC_LIM", "LIM_APPROACH_SYM",
"FUNC_INT", "FUNC_SUM", "FUNC_PROD", "FUNC_EXP", "FUNC_LOG",
"FUNC_LG", "FUNC_LN", "FUNC_SIN", "FUNC_COS", "FUNC_TAN",
"FUNC_CSC", "FUNC_SEC", "FUNC_COT", "FUNC_ARCSIN",
"FUNC_ARCCOS", "FUNC_ARCTAN", "FUNC_ARCCSC", "FUNC_ARCSEC",
"FUNC_ARCCOT", "FUNC_SINH", "FUNC_COSH", "FUNC_TANH",
"FUNC_ARSINH", "FUNC_ARCOSH", "FUNC_ARTANH", "L_FLOOR",
"R_FLOOR", "L_CEIL", "R_CEIL", "FUNC_SQRT", "FUNC_OVERLINE",
"CMD_TIMES", "CMD_CDOT", "CMD_DIV", "CMD_FRAC", "CMD_BINOM",
"CMD_DBINOM", "CMD_TBINOM", "CMD_MATHIT", "UNDERSCORE",
"CARET", "COLON", "DIFFERENTIAL", "LETTER", "DIGIT",
"EQUAL", "NEQ", "LT", "LTE", "LTE_Q", "LTE_S", "GT",
"GTE", "GTE_Q", "GTE_S", "BANG", "SINGLE_QUOTES",
"SYMBOL" ]
RULE_math = 0
RULE_relation = 1
RULE_equality = 2
RULE_expr = 3
RULE_additive = 4
RULE_mp = 5
RULE_mp_nofunc = 6
RULE_unary = 7
RULE_unary_nofunc = 8
RULE_postfix = 9
RULE_postfix_nofunc = 10
RULE_postfix_op = 11
RULE_eval_at = 12
RULE_eval_at_sub = 13
RULE_eval_at_sup = 14
RULE_exp = 15
RULE_exp_nofunc = 16
RULE_comp = 17
RULE_comp_nofunc = 18
RULE_group = 19
RULE_abs_group = 20
RULE_number = 21
RULE_atom = 22
RULE_bra = 23
RULE_ket = 24
RULE_mathit = 25
RULE_mathit_text = 26
RULE_frac = 27
RULE_binom = 28
RULE_floor = 29
RULE_ceil = 30
RULE_func_normal = 31
RULE_func = 32
RULE_args = 33
RULE_limit_sub = 34
RULE_func_arg = 35
RULE_func_arg_noparens = 36
RULE_subexpr = 37
RULE_supexpr = 38
RULE_subeq = 39
RULE_supeq = 40
ruleNames = [ "math", "relation", "equality", "expr", "additive", "mp",
"mp_nofunc", "unary", "unary_nofunc", "postfix", "postfix_nofunc",
"postfix_op", "eval_at", "eval_at_sub", "eval_at_sup",
"exp", "exp_nofunc", "comp", "comp_nofunc", "group",
"abs_group", "number", "atom", "bra", "ket", "mathit",
"mathit_text", "frac", "binom", "floor", "ceil", "func_normal",
"func", "args", "limit_sub", "func_arg", "func_arg_noparens",
"subexpr", "supexpr", "subeq", "supeq" ]
EOF = Token.EOF
T__0=1
T__1=2
WS=3
THINSPACE=4
MEDSPACE=5
THICKSPACE=6
QUAD=7
QQUAD=8
NEGTHINSPACE=9
NEGMEDSPACE=10
NEGTHICKSPACE=11
CMD_LEFT=12
CMD_RIGHT=13
IGNORE=14
ADD=15
SUB=16
MUL=17
DIV=18
L_PAREN=19
R_PAREN=20
L_BRACE=21
R_BRACE=22
L_BRACE_LITERAL=23
R_BRACE_LITERAL=24
L_BRACKET=25
R_BRACKET=26
BAR=27
R_BAR=28
L_BAR=29
L_ANGLE=30
R_ANGLE=31
FUNC_LIM=32
LIM_APPROACH_SYM=33
FUNC_INT=34
FUNC_SUM=35
FUNC_PROD=36
FUNC_EXP=37
FUNC_LOG=38
FUNC_LG=39
FUNC_LN=40
FUNC_SIN=41
FUNC_COS=42
FUNC_TAN=43
FUNC_CSC=44
FUNC_SEC=45
FUNC_COT=46
FUNC_ARCSIN=47
FUNC_ARCCOS=48
FUNC_ARCTAN=49
FUNC_ARCCSC=50
FUNC_ARCSEC=51
FUNC_ARCCOT=52
FUNC_SINH=53
FUNC_COSH=54
FUNC_TANH=55
FUNC_ARSINH=56
FUNC_ARCOSH=57
FUNC_ARTANH=58
L_FLOOR=59
R_FLOOR=60
L_CEIL=61
R_CEIL=62
FUNC_SQRT=63
FUNC_OVERLINE=64
CMD_TIMES=65
CMD_CDOT=66
CMD_DIV=67
CMD_FRAC=68
CMD_BINOM=69
CMD_DBINOM=70
CMD_TBINOM=71
CMD_MATHIT=72
UNDERSCORE=73
CARET=74
COLON=75
DIFFERENTIAL=76
LETTER=77
DIGIT=78
EQUAL=79
NEQ=80
LT=81
LTE=82
LTE_Q=83
LTE_S=84
GT=85
GTE=86
GTE_Q=87
GTE_S=88
BANG=89
SINGLE_QUOTES=90
SYMBOL=91
def __init__(self, input:TokenStream, output:TextIO = sys.stdout):
super().__init__(input, output)
self.checkVersion("4.11.1")
self._interp = ParserATNSimulator(self, self.atn, self.decisionsToDFA, self.sharedContextCache)
self._predicates = None
class MathContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def relation(self):
return self.getTypedRuleContext(LaTeXParser.RelationContext,0)
def getRuleIndex(self):
return LaTeXParser.RULE_math
def math(self):
localctx = LaTeXParser.MathContext(self, self._ctx, self.state)
self.enterRule(localctx, 0, self.RULE_math)
try:
self.enterOuterAlt(localctx, 1)
self.state = 82
self.relation(0)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class RelationContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def expr(self):
return self.getTypedRuleContext(LaTeXParser.ExprContext,0)
def relation(self, i:int=None):
if i is None:
return self.getTypedRuleContexts(LaTeXParser.RelationContext)
else:
return self.getTypedRuleContext(LaTeXParser.RelationContext,i)
def EQUAL(self):
return self.getToken(LaTeXParser.EQUAL, 0)
def LT(self):
return self.getToken(LaTeXParser.LT, 0)
def LTE(self):
return self.getToken(LaTeXParser.LTE, 0)
def GT(self):
return self.getToken(LaTeXParser.GT, 0)
def GTE(self):
return self.getToken(LaTeXParser.GTE, 0)
def NEQ(self):
return self.getToken(LaTeXParser.NEQ, 0)
def getRuleIndex(self):
return LaTeXParser.RULE_relation
def relation(self, _p:int=0):
_parentctx = self._ctx
_parentState = self.state
localctx = LaTeXParser.RelationContext(self, self._ctx, _parentState)
_prevctx = localctx
_startState = 2
self.enterRecursionRule(localctx, 2, self.RULE_relation, _p)
self._la = 0 # Token type
try:
self.enterOuterAlt(localctx, 1)
self.state = 85
self.expr()
self._ctx.stop = self._input.LT(-1)
self.state = 92
self._errHandler.sync(self)
_alt = self._interp.adaptivePredict(self._input,0,self._ctx)
while _alt!=2 and _alt!=ATN.INVALID_ALT_NUMBER:
if _alt==1:
if self._parseListeners is not None:
self.triggerExitRuleEvent()
_prevctx = localctx
localctx = LaTeXParser.RelationContext(self, _parentctx, _parentState)
self.pushNewRecursionContext(localctx, _startState, self.RULE_relation)
self.state = 87
if not self.precpred(self._ctx, 2):
from antlr4.error.Errors import FailedPredicateException
raise FailedPredicateException(self, "self.precpred(self._ctx, 2)")
self.state = 88
_la = self._input.LA(1)
if not((((_la - 79)) & ~0x3f) == 0 and ((1 << (_la - 79)) & 207) != 0):
self._errHandler.recoverInline(self)
else:
self._errHandler.reportMatch(self)
self.consume()
self.state = 89
self.relation(3)
self.state = 94
self._errHandler.sync(self)
_alt = self._interp.adaptivePredict(self._input,0,self._ctx)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.unrollRecursionContexts(_parentctx)
return localctx
class EqualityContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def expr(self, i:int=None):
if i is None:
return self.getTypedRuleContexts(LaTeXParser.ExprContext)
else:
return self.getTypedRuleContext(LaTeXParser.ExprContext,i)
def EQUAL(self):
return self.getToken(LaTeXParser.EQUAL, 0)
def getRuleIndex(self):
return LaTeXParser.RULE_equality
def equality(self):
localctx = LaTeXParser.EqualityContext(self, self._ctx, self.state)
self.enterRule(localctx, 4, self.RULE_equality)
try:
self.enterOuterAlt(localctx, 1)
self.state = 95
self.expr()
self.state = 96
self.match(LaTeXParser.EQUAL)
self.state = 97
self.expr()
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class ExprContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def additive(self):
return self.getTypedRuleContext(LaTeXParser.AdditiveContext,0)
def getRuleIndex(self):
return LaTeXParser.RULE_expr
def expr(self):
localctx = LaTeXParser.ExprContext(self, self._ctx, self.state)
self.enterRule(localctx, 6, self.RULE_expr)
try:
self.enterOuterAlt(localctx, 1)
self.state = 99
self.additive(0)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class AdditiveContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def mp(self):
return self.getTypedRuleContext(LaTeXParser.MpContext,0)
def additive(self, i:int=None):
if i is None:
return self.getTypedRuleContexts(LaTeXParser.AdditiveContext)
else:
return self.getTypedRuleContext(LaTeXParser.AdditiveContext,i)
def ADD(self):
return self.getToken(LaTeXParser.ADD, 0)
def SUB(self):
return self.getToken(LaTeXParser.SUB, 0)
def getRuleIndex(self):
return LaTeXParser.RULE_additive
def additive(self, _p:int=0):
_parentctx = self._ctx
_parentState = self.state
localctx = LaTeXParser.AdditiveContext(self, self._ctx, _parentState)
_prevctx = localctx
_startState = 8
self.enterRecursionRule(localctx, 8, self.RULE_additive, _p)
self._la = 0 # Token type
try:
self.enterOuterAlt(localctx, 1)
self.state = 102
self.mp(0)
self._ctx.stop = self._input.LT(-1)
self.state = 109
self._errHandler.sync(self)
_alt = self._interp.adaptivePredict(self._input,1,self._ctx)
while _alt!=2 and _alt!=ATN.INVALID_ALT_NUMBER:
if _alt==1:
if self._parseListeners is not None:
self.triggerExitRuleEvent()
_prevctx = localctx
localctx = LaTeXParser.AdditiveContext(self, _parentctx, _parentState)
self.pushNewRecursionContext(localctx, _startState, self.RULE_additive)
self.state = 104
if not self.precpred(self._ctx, 2):
from antlr4.error.Errors import FailedPredicateException
raise FailedPredicateException(self, "self.precpred(self._ctx, 2)")
self.state = 105
_la = self._input.LA(1)
if not(_la==15 or _la==16):
self._errHandler.recoverInline(self)
else:
self._errHandler.reportMatch(self)
self.consume()
self.state = 106
self.additive(3)
self.state = 111
self._errHandler.sync(self)
_alt = self._interp.adaptivePredict(self._input,1,self._ctx)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.unrollRecursionContexts(_parentctx)
return localctx
class MpContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def unary(self):
return self.getTypedRuleContext(LaTeXParser.UnaryContext,0)
def mp(self, i:int=None):
if i is None:
return self.getTypedRuleContexts(LaTeXParser.MpContext)
else:
return self.getTypedRuleContext(LaTeXParser.MpContext,i)
def MUL(self):
return self.getToken(LaTeXParser.MUL, 0)
def CMD_TIMES(self):
return self.getToken(LaTeXParser.CMD_TIMES, 0)
def CMD_CDOT(self):
return self.getToken(LaTeXParser.CMD_CDOT, 0)
def DIV(self):
return self.getToken(LaTeXParser.DIV, 0)
def CMD_DIV(self):
return self.getToken(LaTeXParser.CMD_DIV, 0)
def COLON(self):
return self.getToken(LaTeXParser.COLON, 0)
def getRuleIndex(self):
return LaTeXParser.RULE_mp
def mp(self, _p:int=0):
_parentctx = self._ctx
_parentState = self.state
localctx = LaTeXParser.MpContext(self, self._ctx, _parentState)
_prevctx = localctx
_startState = 10
self.enterRecursionRule(localctx, 10, self.RULE_mp, _p)
self._la = 0 # Token type
try:
self.enterOuterAlt(localctx, 1)
self.state = 113
self.unary()
self._ctx.stop = self._input.LT(-1)
self.state = 120
self._errHandler.sync(self)
_alt = self._interp.adaptivePredict(self._input,2,self._ctx)
while _alt!=2 and _alt!=ATN.INVALID_ALT_NUMBER:
if _alt==1:
if self._parseListeners is not None:
self.triggerExitRuleEvent()
_prevctx = localctx
localctx = LaTeXParser.MpContext(self, _parentctx, _parentState)
self.pushNewRecursionContext(localctx, _startState, self.RULE_mp)
self.state = 115
if not self.precpred(self._ctx, 2):
from antlr4.error.Errors import FailedPredicateException
raise FailedPredicateException(self, "self.precpred(self._ctx, 2)")
self.state = 116
_la = self._input.LA(1)
if not((((_la - 17)) & ~0x3f) == 0 and ((1 << (_la - 17)) & 290200700988686339) != 0):
self._errHandler.recoverInline(self)
else:
self._errHandler.reportMatch(self)
self.consume()
self.state = 117
self.mp(3)
self.state = 122
self._errHandler.sync(self)
_alt = self._interp.adaptivePredict(self._input,2,self._ctx)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.unrollRecursionContexts(_parentctx)
return localctx
class Mp_nofuncContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def unary_nofunc(self):
return self.getTypedRuleContext(LaTeXParser.Unary_nofuncContext,0)
def mp_nofunc(self, i:int=None):
if i is None:
return self.getTypedRuleContexts(LaTeXParser.Mp_nofuncContext)
else:
return self.getTypedRuleContext(LaTeXParser.Mp_nofuncContext,i)
def MUL(self):
return self.getToken(LaTeXParser.MUL, 0)
def CMD_TIMES(self):
return self.getToken(LaTeXParser.CMD_TIMES, 0)
def CMD_CDOT(self):
return self.getToken(LaTeXParser.CMD_CDOT, 0)
def DIV(self):
return self.getToken(LaTeXParser.DIV, 0)
def CMD_DIV(self):
return self.getToken(LaTeXParser.CMD_DIV, 0)
def COLON(self):
return self.getToken(LaTeXParser.COLON, 0)
def getRuleIndex(self):
return LaTeXParser.RULE_mp_nofunc
def mp_nofunc(self, _p:int=0):
_parentctx = self._ctx
_parentState = self.state
localctx = LaTeXParser.Mp_nofuncContext(self, self._ctx, _parentState)
_prevctx = localctx
_startState = 12
self.enterRecursionRule(localctx, 12, self.RULE_mp_nofunc, _p)
self._la = 0 # Token type
try:
self.enterOuterAlt(localctx, 1)
self.state = 124
self.unary_nofunc()
self._ctx.stop = self._input.LT(-1)
self.state = 131
self._errHandler.sync(self)
_alt = self._interp.adaptivePredict(self._input,3,self._ctx)
while _alt!=2 and _alt!=ATN.INVALID_ALT_NUMBER:
if _alt==1:
if self._parseListeners is not None:
self.triggerExitRuleEvent()
_prevctx = localctx
localctx = LaTeXParser.Mp_nofuncContext(self, _parentctx, _parentState)
self.pushNewRecursionContext(localctx, _startState, self.RULE_mp_nofunc)
self.state = 126
if not self.precpred(self._ctx, 2):
from antlr4.error.Errors import FailedPredicateException
raise FailedPredicateException(self, "self.precpred(self._ctx, 2)")
self.state = 127
_la = self._input.LA(1)
if not((((_la - 17)) & ~0x3f) == 0 and ((1 << (_la - 17)) & 290200700988686339) != 0):
self._errHandler.recoverInline(self)
else:
self._errHandler.reportMatch(self)
self.consume()
self.state = 128
self.mp_nofunc(3)
self.state = 133
self._errHandler.sync(self)
_alt = self._interp.adaptivePredict(self._input,3,self._ctx)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.unrollRecursionContexts(_parentctx)
return localctx
class UnaryContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def unary(self):
return self.getTypedRuleContext(LaTeXParser.UnaryContext,0)
def ADD(self):
return self.getToken(LaTeXParser.ADD, 0)
def SUB(self):
return self.getToken(LaTeXParser.SUB, 0)
def postfix(self, i:int=None):
if i is None:
return self.getTypedRuleContexts(LaTeXParser.PostfixContext)
else:
return self.getTypedRuleContext(LaTeXParser.PostfixContext,i)
def getRuleIndex(self):
return LaTeXParser.RULE_unary
def unary(self):
localctx = LaTeXParser.UnaryContext(self, self._ctx, self.state)
self.enterRule(localctx, 14, self.RULE_unary)
self._la = 0 # Token type
try:
self.state = 141
self._errHandler.sync(self)
token = self._input.LA(1)
if token in [15, 16]:
self.enterOuterAlt(localctx, 1)
self.state = 134
_la = self._input.LA(1)
if not(_la==15 or _la==16):
self._errHandler.recoverInline(self)
else:
self._errHandler.reportMatch(self)
self.consume()
self.state = 135
self.unary()
pass
elif token in [19, 21, 23, 25, 27, 29, 30, 32, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 61, 63, 64, 68, 69, 70, 71, 72, 76, 77, 78, 91]:
self.enterOuterAlt(localctx, 2)
self.state = 137
self._errHandler.sync(self)
_alt = 1
while _alt!=2 and _alt!=ATN.INVALID_ALT_NUMBER:
if _alt == 1:
self.state = 136
self.postfix()
else:
raise NoViableAltException(self)
self.state = 139
self._errHandler.sync(self)
_alt = self._interp.adaptivePredict(self._input,4,self._ctx)
pass
else:
raise NoViableAltException(self)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class Unary_nofuncContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def unary_nofunc(self):
return self.getTypedRuleContext(LaTeXParser.Unary_nofuncContext,0)
def ADD(self):
return self.getToken(LaTeXParser.ADD, 0)
def SUB(self):
return self.getToken(LaTeXParser.SUB, 0)
def postfix(self):
return self.getTypedRuleContext(LaTeXParser.PostfixContext,0)
def postfix_nofunc(self, i:int=None):
if i is None:
return self.getTypedRuleContexts(LaTeXParser.Postfix_nofuncContext)
else:
return self.getTypedRuleContext(LaTeXParser.Postfix_nofuncContext,i)
def getRuleIndex(self):
return LaTeXParser.RULE_unary_nofunc
def unary_nofunc(self):
localctx = LaTeXParser.Unary_nofuncContext(self, self._ctx, self.state)
self.enterRule(localctx, 16, self.RULE_unary_nofunc)
self._la = 0 # Token type
try:
self.state = 152
self._errHandler.sync(self)
token = self._input.LA(1)
if token in [15, 16]:
self.enterOuterAlt(localctx, 1)
self.state = 143
_la = self._input.LA(1)
if not(_la==15 or _la==16):
self._errHandler.recoverInline(self)
else:
self._errHandler.reportMatch(self)
self.consume()
self.state = 144
self.unary_nofunc()
pass
elif token in [19, 21, 23, 25, 27, 29, 30, 32, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 61, 63, 64, 68, 69, 70, 71, 72, 76, 77, 78, 91]:
self.enterOuterAlt(localctx, 2)
self.state = 145
self.postfix()
self.state = 149
self._errHandler.sync(self)
_alt = self._interp.adaptivePredict(self._input,6,self._ctx)
while _alt!=2 and _alt!=ATN.INVALID_ALT_NUMBER:
if _alt==1:
self.state = 146
self.postfix_nofunc()
self.state = 151
self._errHandler.sync(self)
_alt = self._interp.adaptivePredict(self._input,6,self._ctx)
pass
else:
raise NoViableAltException(self)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class PostfixContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def exp(self):
return self.getTypedRuleContext(LaTeXParser.ExpContext,0)
def postfix_op(self, i:int=None):
if i is None:
return self.getTypedRuleContexts(LaTeXParser.Postfix_opContext)
else:
return self.getTypedRuleContext(LaTeXParser.Postfix_opContext,i)
def getRuleIndex(self):
return LaTeXParser.RULE_postfix
def postfix(self):
localctx = LaTeXParser.PostfixContext(self, self._ctx, self.state)
self.enterRule(localctx, 18, self.RULE_postfix)
try:
self.enterOuterAlt(localctx, 1)
self.state = 154
self.exp(0)
self.state = 158
self._errHandler.sync(self)
_alt = self._interp.adaptivePredict(self._input,8,self._ctx)
while _alt!=2 and _alt!=ATN.INVALID_ALT_NUMBER:
if _alt==1:
self.state = 155
self.postfix_op()
self.state = 160
self._errHandler.sync(self)
_alt = self._interp.adaptivePredict(self._input,8,self._ctx)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class Postfix_nofuncContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def exp_nofunc(self):
return self.getTypedRuleContext(LaTeXParser.Exp_nofuncContext,0)
def postfix_op(self, i:int=None):
if i is None:
return self.getTypedRuleContexts(LaTeXParser.Postfix_opContext)
else:
return self.getTypedRuleContext(LaTeXParser.Postfix_opContext,i)
def getRuleIndex(self):
return LaTeXParser.RULE_postfix_nofunc
def postfix_nofunc(self):
localctx = LaTeXParser.Postfix_nofuncContext(self, self._ctx, self.state)
self.enterRule(localctx, 20, self.RULE_postfix_nofunc)
try:
self.enterOuterAlt(localctx, 1)
self.state = 161
self.exp_nofunc(0)
self.state = 165
self._errHandler.sync(self)
_alt = self._interp.adaptivePredict(self._input,9,self._ctx)
while _alt!=2 and _alt!=ATN.INVALID_ALT_NUMBER:
if _alt==1:
self.state = 162
self.postfix_op()
self.state = 167
self._errHandler.sync(self)
_alt = self._interp.adaptivePredict(self._input,9,self._ctx)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class Postfix_opContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def BANG(self):
return self.getToken(LaTeXParser.BANG, 0)
def eval_at(self):
return self.getTypedRuleContext(LaTeXParser.Eval_atContext,0)
def getRuleIndex(self):
return LaTeXParser.RULE_postfix_op
def postfix_op(self):
localctx = LaTeXParser.Postfix_opContext(self, self._ctx, self.state)
self.enterRule(localctx, 22, self.RULE_postfix_op)
try:
self.state = 170
self._errHandler.sync(self)
token = self._input.LA(1)
if token in [89]:
self.enterOuterAlt(localctx, 1)
self.state = 168
self.match(LaTeXParser.BANG)
pass
elif token in [27]:
self.enterOuterAlt(localctx, 2)
self.state = 169
self.eval_at()
pass
else:
raise NoViableAltException(self)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class Eval_atContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def BAR(self):
return self.getToken(LaTeXParser.BAR, 0)
def eval_at_sup(self):
return self.getTypedRuleContext(LaTeXParser.Eval_at_supContext,0)
def eval_at_sub(self):
return self.getTypedRuleContext(LaTeXParser.Eval_at_subContext,0)
def getRuleIndex(self):
return LaTeXParser.RULE_eval_at
def eval_at(self):
localctx = LaTeXParser.Eval_atContext(self, self._ctx, self.state)
self.enterRule(localctx, 24, self.RULE_eval_at)
try:
self.enterOuterAlt(localctx, 1)
self.state = 172
self.match(LaTeXParser.BAR)
self.state = 178
self._errHandler.sync(self)
la_ = self._interp.adaptivePredict(self._input,11,self._ctx)
if la_ == 1:
self.state = 173
self.eval_at_sup()
pass
elif la_ == 2:
self.state = 174
self.eval_at_sub()
pass
elif la_ == 3:
self.state = 175
self.eval_at_sup()
self.state = 176
self.eval_at_sub()
pass
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class Eval_at_subContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def UNDERSCORE(self):
return self.getToken(LaTeXParser.UNDERSCORE, 0)
def L_BRACE(self):
return self.getToken(LaTeXParser.L_BRACE, 0)
def R_BRACE(self):
return self.getToken(LaTeXParser.R_BRACE, 0)
def expr(self):
return self.getTypedRuleContext(LaTeXParser.ExprContext,0)
def equality(self):
return self.getTypedRuleContext(LaTeXParser.EqualityContext,0)
def getRuleIndex(self):
return LaTeXParser.RULE_eval_at_sub
def eval_at_sub(self):
localctx = LaTeXParser.Eval_at_subContext(self, self._ctx, self.state)
self.enterRule(localctx, 26, self.RULE_eval_at_sub)
try:
self.enterOuterAlt(localctx, 1)
self.state = 180
self.match(LaTeXParser.UNDERSCORE)
self.state = 181
self.match(LaTeXParser.L_BRACE)
self.state = 184
self._errHandler.sync(self)
la_ = self._interp.adaptivePredict(self._input,12,self._ctx)
if la_ == 1:
self.state = 182
self.expr()
pass
elif la_ == 2:
self.state = 183
self.equality()
pass
self.state = 186
self.match(LaTeXParser.R_BRACE)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class Eval_at_supContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def CARET(self):
return self.getToken(LaTeXParser.CARET, 0)
def L_BRACE(self):
return self.getToken(LaTeXParser.L_BRACE, 0)
def R_BRACE(self):
return self.getToken(LaTeXParser.R_BRACE, 0)
def expr(self):
return self.getTypedRuleContext(LaTeXParser.ExprContext,0)
def equality(self):
return self.getTypedRuleContext(LaTeXParser.EqualityContext,0)
def getRuleIndex(self):
return LaTeXParser.RULE_eval_at_sup
def eval_at_sup(self):
localctx = LaTeXParser.Eval_at_supContext(self, self._ctx, self.state)
self.enterRule(localctx, 28, self.RULE_eval_at_sup)
try:
self.enterOuterAlt(localctx, 1)
self.state = 188
self.match(LaTeXParser.CARET)
self.state = 189
self.match(LaTeXParser.L_BRACE)
self.state = 192
self._errHandler.sync(self)
la_ = self._interp.adaptivePredict(self._input,13,self._ctx)
if la_ == 1:
self.state = 190
self.expr()
pass
elif la_ == 2:
self.state = 191
self.equality()
pass
self.state = 194
self.match(LaTeXParser.R_BRACE)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class ExpContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def comp(self):
return self.getTypedRuleContext(LaTeXParser.CompContext,0)
def exp(self):
return self.getTypedRuleContext(LaTeXParser.ExpContext,0)
def CARET(self):
return self.getToken(LaTeXParser.CARET, 0)
def atom(self):
return self.getTypedRuleContext(LaTeXParser.AtomContext,0)
def L_BRACE(self):
return self.getToken(LaTeXParser.L_BRACE, 0)
def expr(self):
return self.getTypedRuleContext(LaTeXParser.ExprContext,0)
def R_BRACE(self):
return self.getToken(LaTeXParser.R_BRACE, 0)
def subexpr(self):
return self.getTypedRuleContext(LaTeXParser.SubexprContext,0)
def getRuleIndex(self):
return LaTeXParser.RULE_exp
def exp(self, _p:int=0):
_parentctx = self._ctx
_parentState = self.state
localctx = LaTeXParser.ExpContext(self, self._ctx, _parentState)
_prevctx = localctx
_startState = 30
self.enterRecursionRule(localctx, 30, self.RULE_exp, _p)
try:
self.enterOuterAlt(localctx, 1)
self.state = 197
self.comp()
self._ctx.stop = self._input.LT(-1)
self.state = 213
self._errHandler.sync(self)
_alt = self._interp.adaptivePredict(self._input,16,self._ctx)
while _alt!=2 and _alt!=ATN.INVALID_ALT_NUMBER:
if _alt==1:
if self._parseListeners is not None:
self.triggerExitRuleEvent()
_prevctx = localctx
localctx = LaTeXParser.ExpContext(self, _parentctx, _parentState)
self.pushNewRecursionContext(localctx, _startState, self.RULE_exp)
self.state = 199
if not self.precpred(self._ctx, 2):
from antlr4.error.Errors import FailedPredicateException
raise FailedPredicateException(self, "self.precpred(self._ctx, 2)")
self.state = 200
self.match(LaTeXParser.CARET)
self.state = 206
self._errHandler.sync(self)
token = self._input.LA(1)
if token in [27, 29, 30, 68, 69, 70, 71, 72, 76, 77, 78, 91]:
self.state = 201
self.atom()
pass
elif token in [21]:
self.state = 202
self.match(LaTeXParser.L_BRACE)
self.state = 203
self.expr()
self.state = 204
self.match(LaTeXParser.R_BRACE)
pass
else:
raise NoViableAltException(self)
self.state = 209
self._errHandler.sync(self)
la_ = self._interp.adaptivePredict(self._input,15,self._ctx)
if la_ == 1:
self.state = 208
self.subexpr()
self.state = 215
self._errHandler.sync(self)
_alt = self._interp.adaptivePredict(self._input,16,self._ctx)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.unrollRecursionContexts(_parentctx)
return localctx
class Exp_nofuncContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def comp_nofunc(self):
return self.getTypedRuleContext(LaTeXParser.Comp_nofuncContext,0)
def exp_nofunc(self):
return self.getTypedRuleContext(LaTeXParser.Exp_nofuncContext,0)
def CARET(self):
return self.getToken(LaTeXParser.CARET, 0)
def atom(self):
return self.getTypedRuleContext(LaTeXParser.AtomContext,0)
def L_BRACE(self):
return self.getToken(LaTeXParser.L_BRACE, 0)
def expr(self):
return self.getTypedRuleContext(LaTeXParser.ExprContext,0)
def R_BRACE(self):
return self.getToken(LaTeXParser.R_BRACE, 0)
def subexpr(self):
return self.getTypedRuleContext(LaTeXParser.SubexprContext,0)
def getRuleIndex(self):
return LaTeXParser.RULE_exp_nofunc
def exp_nofunc(self, _p:int=0):
_parentctx = self._ctx
_parentState = self.state
localctx = LaTeXParser.Exp_nofuncContext(self, self._ctx, _parentState)
_prevctx = localctx
_startState = 32
self.enterRecursionRule(localctx, 32, self.RULE_exp_nofunc, _p)
try:
self.enterOuterAlt(localctx, 1)
self.state = 217
self.comp_nofunc()
self._ctx.stop = self._input.LT(-1)
self.state = 233
self._errHandler.sync(self)
_alt = self._interp.adaptivePredict(self._input,19,self._ctx)
while _alt!=2 and _alt!=ATN.INVALID_ALT_NUMBER:
if _alt==1:
if self._parseListeners is not None:
self.triggerExitRuleEvent()
_prevctx = localctx
localctx = LaTeXParser.Exp_nofuncContext(self, _parentctx, _parentState)
self.pushNewRecursionContext(localctx, _startState, self.RULE_exp_nofunc)
self.state = 219
if not self.precpred(self._ctx, 2):
from antlr4.error.Errors import FailedPredicateException
raise FailedPredicateException(self, "self.precpred(self._ctx, 2)")
self.state = 220
self.match(LaTeXParser.CARET)
self.state = 226
self._errHandler.sync(self)
token = self._input.LA(1)
if token in [27, 29, 30, 68, 69, 70, 71, 72, 76, 77, 78, 91]:
self.state = 221
self.atom()
pass
elif token in [21]:
self.state = 222
self.match(LaTeXParser.L_BRACE)
self.state = 223
self.expr()
self.state = 224
self.match(LaTeXParser.R_BRACE)
pass
else:
raise NoViableAltException(self)
self.state = 229
self._errHandler.sync(self)
la_ = self._interp.adaptivePredict(self._input,18,self._ctx)
if la_ == 1:
self.state = 228
self.subexpr()
self.state = 235
self._errHandler.sync(self)
_alt = self._interp.adaptivePredict(self._input,19,self._ctx)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.unrollRecursionContexts(_parentctx)
return localctx
class CompContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def group(self):
return self.getTypedRuleContext(LaTeXParser.GroupContext,0)
def abs_group(self):
return self.getTypedRuleContext(LaTeXParser.Abs_groupContext,0)
def func(self):
return self.getTypedRuleContext(LaTeXParser.FuncContext,0)
def atom(self):
return self.getTypedRuleContext(LaTeXParser.AtomContext,0)
def floor(self):
return self.getTypedRuleContext(LaTeXParser.FloorContext,0)
def ceil(self):
return self.getTypedRuleContext(LaTeXParser.CeilContext,0)
def getRuleIndex(self):
return LaTeXParser.RULE_comp
def comp(self):
localctx = LaTeXParser.CompContext(self, self._ctx, self.state)
self.enterRule(localctx, 34, self.RULE_comp)
try:
self.state = 242
self._errHandler.sync(self)
la_ = self._interp.adaptivePredict(self._input,20,self._ctx)
if la_ == 1:
self.enterOuterAlt(localctx, 1)
self.state = 236
self.group()
pass
elif la_ == 2:
self.enterOuterAlt(localctx, 2)
self.state = 237
self.abs_group()
pass
elif la_ == 3:
self.enterOuterAlt(localctx, 3)
self.state = 238
self.func()
pass
elif la_ == 4:
self.enterOuterAlt(localctx, 4)
self.state = 239
self.atom()
pass
elif la_ == 5:
self.enterOuterAlt(localctx, 5)
self.state = 240
self.floor()
pass
elif la_ == 6:
self.enterOuterAlt(localctx, 6)
self.state = 241
self.ceil()
pass
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class Comp_nofuncContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def group(self):
return self.getTypedRuleContext(LaTeXParser.GroupContext,0)
def abs_group(self):
return self.getTypedRuleContext(LaTeXParser.Abs_groupContext,0)
def atom(self):
return self.getTypedRuleContext(LaTeXParser.AtomContext,0)
def floor(self):
return self.getTypedRuleContext(LaTeXParser.FloorContext,0)
def ceil(self):
return self.getTypedRuleContext(LaTeXParser.CeilContext,0)
def getRuleIndex(self):
return LaTeXParser.RULE_comp_nofunc
def comp_nofunc(self):
localctx = LaTeXParser.Comp_nofuncContext(self, self._ctx, self.state)
self.enterRule(localctx, 36, self.RULE_comp_nofunc)
try:
self.state = 249
self._errHandler.sync(self)
la_ = self._interp.adaptivePredict(self._input,21,self._ctx)
if la_ == 1:
self.enterOuterAlt(localctx, 1)
self.state = 244
self.group()
pass
elif la_ == 2:
self.enterOuterAlt(localctx, 2)
self.state = 245
self.abs_group()
pass
elif la_ == 3:
self.enterOuterAlt(localctx, 3)
self.state = 246
self.atom()
pass
elif la_ == 4:
self.enterOuterAlt(localctx, 4)
self.state = 247
self.floor()
pass
elif la_ == 5:
self.enterOuterAlt(localctx, 5)
self.state = 248
self.ceil()
pass
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class GroupContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def L_PAREN(self):
return self.getToken(LaTeXParser.L_PAREN, 0)
def expr(self):
return self.getTypedRuleContext(LaTeXParser.ExprContext,0)
def R_PAREN(self):
return self.getToken(LaTeXParser.R_PAREN, 0)
def L_BRACKET(self):
return self.getToken(LaTeXParser.L_BRACKET, 0)
def R_BRACKET(self):
return self.getToken(LaTeXParser.R_BRACKET, 0)
def L_BRACE(self):
return self.getToken(LaTeXParser.L_BRACE, 0)
def R_BRACE(self):
return self.getToken(LaTeXParser.R_BRACE, 0)
def L_BRACE_LITERAL(self):
return self.getToken(LaTeXParser.L_BRACE_LITERAL, 0)
def R_BRACE_LITERAL(self):
return self.getToken(LaTeXParser.R_BRACE_LITERAL, 0)
def getRuleIndex(self):
return LaTeXParser.RULE_group
def group(self):
localctx = LaTeXParser.GroupContext(self, self._ctx, self.state)
self.enterRule(localctx, 38, self.RULE_group)
try:
self.state = 267
self._errHandler.sync(self)
token = self._input.LA(1)
if token in [19]:
self.enterOuterAlt(localctx, 1)
self.state = 251
self.match(LaTeXParser.L_PAREN)
self.state = 252
self.expr()
self.state = 253
self.match(LaTeXParser.R_PAREN)
pass
elif token in [25]:
self.enterOuterAlt(localctx, 2)
self.state = 255
self.match(LaTeXParser.L_BRACKET)
self.state = 256
self.expr()
self.state = 257
self.match(LaTeXParser.R_BRACKET)
pass
elif token in [21]:
self.enterOuterAlt(localctx, 3)
self.state = 259
self.match(LaTeXParser.L_BRACE)
self.state = 260
self.expr()
self.state = 261
self.match(LaTeXParser.R_BRACE)
pass
elif token in [23]:
self.enterOuterAlt(localctx, 4)
self.state = 263
self.match(LaTeXParser.L_BRACE_LITERAL)
self.state = 264
self.expr()
self.state = 265
self.match(LaTeXParser.R_BRACE_LITERAL)
pass
else:
raise NoViableAltException(self)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class Abs_groupContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def BAR(self, i:int=None):
if i is None:
return self.getTokens(LaTeXParser.BAR)
else:
return self.getToken(LaTeXParser.BAR, i)
def expr(self):
return self.getTypedRuleContext(LaTeXParser.ExprContext,0)
def getRuleIndex(self):
return LaTeXParser.RULE_abs_group
def abs_group(self):
localctx = LaTeXParser.Abs_groupContext(self, self._ctx, self.state)
self.enterRule(localctx, 40, self.RULE_abs_group)
try:
self.enterOuterAlt(localctx, 1)
self.state = 269
self.match(LaTeXParser.BAR)
self.state = 270
self.expr()
self.state = 271
self.match(LaTeXParser.BAR)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class NumberContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def DIGIT(self, i:int=None):
if i is None:
return self.getTokens(LaTeXParser.DIGIT)
else:
return self.getToken(LaTeXParser.DIGIT, i)
def getRuleIndex(self):
return LaTeXParser.RULE_number
def number(self):
localctx = LaTeXParser.NumberContext(self, self._ctx, self.state)
self.enterRule(localctx, 42, self.RULE_number)
try:
self.enterOuterAlt(localctx, 1)
self.state = 274
self._errHandler.sync(self)
_alt = 1
while _alt!=2 and _alt!=ATN.INVALID_ALT_NUMBER:
if _alt == 1:
self.state = 273
self.match(LaTeXParser.DIGIT)
else:
raise NoViableAltException(self)
self.state = 276
self._errHandler.sync(self)
_alt = self._interp.adaptivePredict(self._input,23,self._ctx)
self.state = 284
self._errHandler.sync(self)
_alt = self._interp.adaptivePredict(self._input,24,self._ctx)
while _alt!=2 and _alt!=ATN.INVALID_ALT_NUMBER:
if _alt==1:
self.state = 278
self.match(LaTeXParser.T__0)
self.state = 279
self.match(LaTeXParser.DIGIT)
self.state = 280
self.match(LaTeXParser.DIGIT)
self.state = 281
self.match(LaTeXParser.DIGIT)
self.state = 286
self._errHandler.sync(self)
_alt = self._interp.adaptivePredict(self._input,24,self._ctx)
self.state = 293
self._errHandler.sync(self)
la_ = self._interp.adaptivePredict(self._input,26,self._ctx)
if la_ == 1:
self.state = 287
self.match(LaTeXParser.T__1)
self.state = 289
self._errHandler.sync(self)
_alt = 1
while _alt!=2 and _alt!=ATN.INVALID_ALT_NUMBER:
if _alt == 1:
self.state = 288
self.match(LaTeXParser.DIGIT)
else:
raise NoViableAltException(self)
self.state = 291
self._errHandler.sync(self)
_alt = self._interp.adaptivePredict(self._input,25,self._ctx)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class AtomContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def LETTER(self):
return self.getToken(LaTeXParser.LETTER, 0)
def SYMBOL(self):
return self.getToken(LaTeXParser.SYMBOL, 0)
def subexpr(self):
return self.getTypedRuleContext(LaTeXParser.SubexprContext,0)
def SINGLE_QUOTES(self):
return self.getToken(LaTeXParser.SINGLE_QUOTES, 0)
def number(self):
return self.getTypedRuleContext(LaTeXParser.NumberContext,0)
def DIFFERENTIAL(self):
return self.getToken(LaTeXParser.DIFFERENTIAL, 0)
def mathit(self):
return self.getTypedRuleContext(LaTeXParser.MathitContext,0)
def frac(self):
return self.getTypedRuleContext(LaTeXParser.FracContext,0)
def binom(self):
return self.getTypedRuleContext(LaTeXParser.BinomContext,0)
def bra(self):
return self.getTypedRuleContext(LaTeXParser.BraContext,0)
def ket(self):
return self.getTypedRuleContext(LaTeXParser.KetContext,0)
def getRuleIndex(self):
return LaTeXParser.RULE_atom
def atom(self):
localctx = LaTeXParser.AtomContext(self, self._ctx, self.state)
self.enterRule(localctx, 44, self.RULE_atom)
self._la = 0 # Token type
try:
self.state = 317
self._errHandler.sync(self)
token = self._input.LA(1)
if token in [77, 91]:
self.enterOuterAlt(localctx, 1)
self.state = 295
_la = self._input.LA(1)
if not(_la==77 or _la==91):
self._errHandler.recoverInline(self)
else:
self._errHandler.reportMatch(self)
self.consume()
self.state = 308
self._errHandler.sync(self)
la_ = self._interp.adaptivePredict(self._input,31,self._ctx)
if la_ == 1:
self.state = 297
self._errHandler.sync(self)
la_ = self._interp.adaptivePredict(self._input,27,self._ctx)
if la_ == 1:
self.state = 296
self.subexpr()
self.state = 300
self._errHandler.sync(self)
la_ = self._interp.adaptivePredict(self._input,28,self._ctx)
if la_ == 1:
self.state = 299
self.match(LaTeXParser.SINGLE_QUOTES)
pass
elif la_ == 2:
self.state = 303
self._errHandler.sync(self)
la_ = self._interp.adaptivePredict(self._input,29,self._ctx)
if la_ == 1:
self.state = 302
self.match(LaTeXParser.SINGLE_QUOTES)
self.state = 306
self._errHandler.sync(self)
la_ = self._interp.adaptivePredict(self._input,30,self._ctx)
if la_ == 1:
self.state = 305
self.subexpr()
pass
pass
elif token in [78]:
self.enterOuterAlt(localctx, 2)
self.state = 310
self.number()
pass
elif token in [76]:
self.enterOuterAlt(localctx, 3)
self.state = 311
self.match(LaTeXParser.DIFFERENTIAL)
pass
elif token in [72]:
self.enterOuterAlt(localctx, 4)
self.state = 312
self.mathit()
pass
elif token in [68]:
self.enterOuterAlt(localctx, 5)
self.state = 313
self.frac()
pass
elif token in [69, 70, 71]:
self.enterOuterAlt(localctx, 6)
self.state = 314
self.binom()
pass
elif token in [30]:
self.enterOuterAlt(localctx, 7)
self.state = 315
self.bra()
pass
elif token in [27, 29]:
self.enterOuterAlt(localctx, 8)
self.state = 316
self.ket()
pass
else:
raise NoViableAltException(self)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class BraContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def L_ANGLE(self):
return self.getToken(LaTeXParser.L_ANGLE, 0)
def expr(self):
return self.getTypedRuleContext(LaTeXParser.ExprContext,0)
def R_BAR(self):
return self.getToken(LaTeXParser.R_BAR, 0)
def BAR(self):
return self.getToken(LaTeXParser.BAR, 0)
def getRuleIndex(self):
return LaTeXParser.RULE_bra
def bra(self):
localctx = LaTeXParser.BraContext(self, self._ctx, self.state)
self.enterRule(localctx, 46, self.RULE_bra)
self._la = 0 # Token type
try:
self.enterOuterAlt(localctx, 1)
self.state = 319
self.match(LaTeXParser.L_ANGLE)
self.state = 320
self.expr()
self.state = 321
_la = self._input.LA(1)
if not(_la==27 or _la==28):
self._errHandler.recoverInline(self)
else:
self._errHandler.reportMatch(self)
self.consume()
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class KetContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def expr(self):
return self.getTypedRuleContext(LaTeXParser.ExprContext,0)
def R_ANGLE(self):
return self.getToken(LaTeXParser.R_ANGLE, 0)
def L_BAR(self):
return self.getToken(LaTeXParser.L_BAR, 0)
def BAR(self):
return self.getToken(LaTeXParser.BAR, 0)
def getRuleIndex(self):
return LaTeXParser.RULE_ket
def ket(self):
localctx = LaTeXParser.KetContext(self, self._ctx, self.state)
self.enterRule(localctx, 48, self.RULE_ket)
self._la = 0 # Token type
try:
self.enterOuterAlt(localctx, 1)
self.state = 323
_la = self._input.LA(1)
if not(_la==27 or _la==29):
self._errHandler.recoverInline(self)
else:
self._errHandler.reportMatch(self)
self.consume()
self.state = 324
self.expr()
self.state = 325
self.match(LaTeXParser.R_ANGLE)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class MathitContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def CMD_MATHIT(self):
return self.getToken(LaTeXParser.CMD_MATHIT, 0)
def L_BRACE(self):
return self.getToken(LaTeXParser.L_BRACE, 0)
def mathit_text(self):
return self.getTypedRuleContext(LaTeXParser.Mathit_textContext,0)
def R_BRACE(self):
return self.getToken(LaTeXParser.R_BRACE, 0)
def getRuleIndex(self):
return LaTeXParser.RULE_mathit
def mathit(self):
localctx = LaTeXParser.MathitContext(self, self._ctx, self.state)
self.enterRule(localctx, 50, self.RULE_mathit)
try:
self.enterOuterAlt(localctx, 1)
self.state = 327
self.match(LaTeXParser.CMD_MATHIT)
self.state = 328
self.match(LaTeXParser.L_BRACE)
self.state = 329
self.mathit_text()
self.state = 330
self.match(LaTeXParser.R_BRACE)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class Mathit_textContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def LETTER(self, i:int=None):
if i is None:
return self.getTokens(LaTeXParser.LETTER)
else:
return self.getToken(LaTeXParser.LETTER, i)
def getRuleIndex(self):
return LaTeXParser.RULE_mathit_text
def mathit_text(self):
localctx = LaTeXParser.Mathit_textContext(self, self._ctx, self.state)
self.enterRule(localctx, 52, self.RULE_mathit_text)
self._la = 0 # Token type
try:
self.enterOuterAlt(localctx, 1)
self.state = 335
self._errHandler.sync(self)
_la = self._input.LA(1)
while _la==77:
self.state = 332
self.match(LaTeXParser.LETTER)
self.state = 337
self._errHandler.sync(self)
_la = self._input.LA(1)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class FracContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
self.upperd = None # Token
self.upper = None # ExprContext
self.lowerd = None # Token
self.lower = None # ExprContext
def CMD_FRAC(self):
return self.getToken(LaTeXParser.CMD_FRAC, 0)
def L_BRACE(self, i:int=None):
if i is None:
return self.getTokens(LaTeXParser.L_BRACE)
else:
return self.getToken(LaTeXParser.L_BRACE, i)
def R_BRACE(self, i:int=None):
if i is None:
return self.getTokens(LaTeXParser.R_BRACE)
else:
return self.getToken(LaTeXParser.R_BRACE, i)
def DIGIT(self, i:int=None):
if i is None:
return self.getTokens(LaTeXParser.DIGIT)
else:
return self.getToken(LaTeXParser.DIGIT, i)
def expr(self, i:int=None):
if i is None:
return self.getTypedRuleContexts(LaTeXParser.ExprContext)
else:
return self.getTypedRuleContext(LaTeXParser.ExprContext,i)
def getRuleIndex(self):
return LaTeXParser.RULE_frac
def frac(self):
localctx = LaTeXParser.FracContext(self, self._ctx, self.state)
self.enterRule(localctx, 54, self.RULE_frac)
try:
self.enterOuterAlt(localctx, 1)
self.state = 338
self.match(LaTeXParser.CMD_FRAC)
self.state = 344
self._errHandler.sync(self)
token = self._input.LA(1)
if token in [78]:
self.state = 339
localctx.upperd = self.match(LaTeXParser.DIGIT)
pass
elif token in [21]:
self.state = 340
self.match(LaTeXParser.L_BRACE)
self.state = 341
localctx.upper = self.expr()
self.state = 342
self.match(LaTeXParser.R_BRACE)
pass
else:
raise NoViableAltException(self)
self.state = 351
self._errHandler.sync(self)
token = self._input.LA(1)
if token in [78]:
self.state = 346
localctx.lowerd = self.match(LaTeXParser.DIGIT)
pass
elif token in [21]:
self.state = 347
self.match(LaTeXParser.L_BRACE)
self.state = 348
localctx.lower = self.expr()
self.state = 349
self.match(LaTeXParser.R_BRACE)
pass
else:
raise NoViableAltException(self)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class BinomContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
self.n = None # ExprContext
self.k = None # ExprContext
def L_BRACE(self, i:int=None):
if i is None:
return self.getTokens(LaTeXParser.L_BRACE)
else:
return self.getToken(LaTeXParser.L_BRACE, i)
def R_BRACE(self, i:int=None):
if i is None:
return self.getTokens(LaTeXParser.R_BRACE)
else:
return self.getToken(LaTeXParser.R_BRACE, i)
def CMD_BINOM(self):
return self.getToken(LaTeXParser.CMD_BINOM, 0)
def CMD_DBINOM(self):
return self.getToken(LaTeXParser.CMD_DBINOM, 0)
def CMD_TBINOM(self):
return self.getToken(LaTeXParser.CMD_TBINOM, 0)
def expr(self, i:int=None):
if i is None:
return self.getTypedRuleContexts(LaTeXParser.ExprContext)
else:
return self.getTypedRuleContext(LaTeXParser.ExprContext,i)
def getRuleIndex(self):
return LaTeXParser.RULE_binom
def binom(self):
localctx = LaTeXParser.BinomContext(self, self._ctx, self.state)
self.enterRule(localctx, 56, self.RULE_binom)
self._la = 0 # Token type
try:
self.enterOuterAlt(localctx, 1)
self.state = 353
_la = self._input.LA(1)
if not((((_la - 69)) & ~0x3f) == 0 and ((1 << (_la - 69)) & 7) != 0):
self._errHandler.recoverInline(self)
else:
self._errHandler.reportMatch(self)
self.consume()
self.state = 354
self.match(LaTeXParser.L_BRACE)
self.state = 355
localctx.n = self.expr()
self.state = 356
self.match(LaTeXParser.R_BRACE)
self.state = 357
self.match(LaTeXParser.L_BRACE)
self.state = 358
localctx.k = self.expr()
self.state = 359
self.match(LaTeXParser.R_BRACE)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class FloorContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
self.val = None # ExprContext
def L_FLOOR(self):
return self.getToken(LaTeXParser.L_FLOOR, 0)
def R_FLOOR(self):
return self.getToken(LaTeXParser.R_FLOOR, 0)
def expr(self):
return self.getTypedRuleContext(LaTeXParser.ExprContext,0)
def getRuleIndex(self):
return LaTeXParser.RULE_floor
def floor(self):
localctx = LaTeXParser.FloorContext(self, self._ctx, self.state)
self.enterRule(localctx, 58, self.RULE_floor)
try:
self.enterOuterAlt(localctx, 1)
self.state = 361
self.match(LaTeXParser.L_FLOOR)
self.state = 362
localctx.val = self.expr()
self.state = 363
self.match(LaTeXParser.R_FLOOR)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class CeilContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
self.val = None # ExprContext
def L_CEIL(self):
return self.getToken(LaTeXParser.L_CEIL, 0)
def R_CEIL(self):
return self.getToken(LaTeXParser.R_CEIL, 0)
def expr(self):
return self.getTypedRuleContext(LaTeXParser.ExprContext,0)
def getRuleIndex(self):
return LaTeXParser.RULE_ceil
def ceil(self):
localctx = LaTeXParser.CeilContext(self, self._ctx, self.state)
self.enterRule(localctx, 60, self.RULE_ceil)
try:
self.enterOuterAlt(localctx, 1)
self.state = 365
self.match(LaTeXParser.L_CEIL)
self.state = 366
localctx.val = self.expr()
self.state = 367
self.match(LaTeXParser.R_CEIL)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class Func_normalContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def FUNC_EXP(self):
return self.getToken(LaTeXParser.FUNC_EXP, 0)
def FUNC_LOG(self):
return self.getToken(LaTeXParser.FUNC_LOG, 0)
def FUNC_LG(self):
return self.getToken(LaTeXParser.FUNC_LG, 0)
def FUNC_LN(self):
return self.getToken(LaTeXParser.FUNC_LN, 0)
def FUNC_SIN(self):
return self.getToken(LaTeXParser.FUNC_SIN, 0)
def FUNC_COS(self):
return self.getToken(LaTeXParser.FUNC_COS, 0)
def FUNC_TAN(self):
return self.getToken(LaTeXParser.FUNC_TAN, 0)
def FUNC_CSC(self):
return self.getToken(LaTeXParser.FUNC_CSC, 0)
def FUNC_SEC(self):
return self.getToken(LaTeXParser.FUNC_SEC, 0)
def FUNC_COT(self):
return self.getToken(LaTeXParser.FUNC_COT, 0)
def FUNC_ARCSIN(self):
return self.getToken(LaTeXParser.FUNC_ARCSIN, 0)
def FUNC_ARCCOS(self):
return self.getToken(LaTeXParser.FUNC_ARCCOS, 0)
def FUNC_ARCTAN(self):
return self.getToken(LaTeXParser.FUNC_ARCTAN, 0)
def FUNC_ARCCSC(self):
return self.getToken(LaTeXParser.FUNC_ARCCSC, 0)
def FUNC_ARCSEC(self):
return self.getToken(LaTeXParser.FUNC_ARCSEC, 0)
def FUNC_ARCCOT(self):
return self.getToken(LaTeXParser.FUNC_ARCCOT, 0)
def FUNC_SINH(self):
return self.getToken(LaTeXParser.FUNC_SINH, 0)
def FUNC_COSH(self):
return self.getToken(LaTeXParser.FUNC_COSH, 0)
def FUNC_TANH(self):
return self.getToken(LaTeXParser.FUNC_TANH, 0)
def FUNC_ARSINH(self):
return self.getToken(LaTeXParser.FUNC_ARSINH, 0)
def FUNC_ARCOSH(self):
return self.getToken(LaTeXParser.FUNC_ARCOSH, 0)
def FUNC_ARTANH(self):
return self.getToken(LaTeXParser.FUNC_ARTANH, 0)
def getRuleIndex(self):
return LaTeXParser.RULE_func_normal
def func_normal(self):
localctx = LaTeXParser.Func_normalContext(self, self._ctx, self.state)
self.enterRule(localctx, 62, self.RULE_func_normal)
self._la = 0 # Token type
try:
self.enterOuterAlt(localctx, 1)
self.state = 369
_la = self._input.LA(1)
if not(((_la) & ~0x3f) == 0 and ((1 << _la) & 576460614864470016) != 0):
self._errHandler.recoverInline(self)
else:
self._errHandler.reportMatch(self)
self.consume()
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class FuncContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
self.root = None # ExprContext
self.base = None # ExprContext
def func_normal(self):
return self.getTypedRuleContext(LaTeXParser.Func_normalContext,0)
def L_PAREN(self):
return self.getToken(LaTeXParser.L_PAREN, 0)
def func_arg(self):
return self.getTypedRuleContext(LaTeXParser.Func_argContext,0)
def R_PAREN(self):
return self.getToken(LaTeXParser.R_PAREN, 0)
def func_arg_noparens(self):
return self.getTypedRuleContext(LaTeXParser.Func_arg_noparensContext,0)
def subexpr(self):
return self.getTypedRuleContext(LaTeXParser.SubexprContext,0)
def supexpr(self):
return self.getTypedRuleContext(LaTeXParser.SupexprContext,0)
def args(self):
return self.getTypedRuleContext(LaTeXParser.ArgsContext,0)
def LETTER(self):
return self.getToken(LaTeXParser.LETTER, 0)
def SYMBOL(self):
return self.getToken(LaTeXParser.SYMBOL, 0)
def SINGLE_QUOTES(self):
return self.getToken(LaTeXParser.SINGLE_QUOTES, 0)
def FUNC_INT(self):
return self.getToken(LaTeXParser.FUNC_INT, 0)
def DIFFERENTIAL(self):
return self.getToken(LaTeXParser.DIFFERENTIAL, 0)
def frac(self):
return self.getTypedRuleContext(LaTeXParser.FracContext,0)
def additive(self):
return self.getTypedRuleContext(LaTeXParser.AdditiveContext,0)
def FUNC_SQRT(self):
return self.getToken(LaTeXParser.FUNC_SQRT, 0)
def L_BRACE(self):
return self.getToken(LaTeXParser.L_BRACE, 0)
def R_BRACE(self):
return self.getToken(LaTeXParser.R_BRACE, 0)
def expr(self, i:int=None):
if i is None:
return self.getTypedRuleContexts(LaTeXParser.ExprContext)
else:
return self.getTypedRuleContext(LaTeXParser.ExprContext,i)
def L_BRACKET(self):
return self.getToken(LaTeXParser.L_BRACKET, 0)
def R_BRACKET(self):
return self.getToken(LaTeXParser.R_BRACKET, 0)
def FUNC_OVERLINE(self):
return self.getToken(LaTeXParser.FUNC_OVERLINE, 0)
def mp(self):
return self.getTypedRuleContext(LaTeXParser.MpContext,0)
def FUNC_SUM(self):
return self.getToken(LaTeXParser.FUNC_SUM, 0)
def FUNC_PROD(self):
return self.getToken(LaTeXParser.FUNC_PROD, 0)
def subeq(self):
return self.getTypedRuleContext(LaTeXParser.SubeqContext,0)
def FUNC_LIM(self):
return self.getToken(LaTeXParser.FUNC_LIM, 0)
def limit_sub(self):
return self.getTypedRuleContext(LaTeXParser.Limit_subContext,0)
def getRuleIndex(self):
return LaTeXParser.RULE_func
def func(self):
localctx = LaTeXParser.FuncContext(self, self._ctx, self.state)
self.enterRule(localctx, 64, self.RULE_func)
self._la = 0 # Token type
try:
self.state = 460
self._errHandler.sync(self)
token = self._input.LA(1)
if token in [37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58]:
self.enterOuterAlt(localctx, 1)
self.state = 371
self.func_normal()
self.state = 384
self._errHandler.sync(self)
la_ = self._interp.adaptivePredict(self._input,40,self._ctx)
if la_ == 1:
self.state = 373
self._errHandler.sync(self)
_la = self._input.LA(1)
if _la==73:
self.state = 372
self.subexpr()
self.state = 376
self._errHandler.sync(self)
_la = self._input.LA(1)
if _la==74:
self.state = 375
self.supexpr()
pass
elif la_ == 2:
self.state = 379
self._errHandler.sync(self)
_la = self._input.LA(1)
if _la==74:
self.state = 378
self.supexpr()
self.state = 382
self._errHandler.sync(self)
_la = self._input.LA(1)
if _la==73:
self.state = 381
self.subexpr()
pass
self.state = 391
self._errHandler.sync(self)
la_ = self._interp.adaptivePredict(self._input,41,self._ctx)
if la_ == 1:
self.state = 386
self.match(LaTeXParser.L_PAREN)
self.state = 387
self.func_arg()
self.state = 388
self.match(LaTeXParser.R_PAREN)
pass
elif la_ == 2:
self.state = 390
self.func_arg_noparens()
pass
pass
elif token in [77, 91]:
self.enterOuterAlt(localctx, 2)
self.state = 393
_la = self._input.LA(1)
if not(_la==77 or _la==91):
self._errHandler.recoverInline(self)
else:
self._errHandler.reportMatch(self)
self.consume()
self.state = 406
self._errHandler.sync(self)
la_ = self._interp.adaptivePredict(self._input,46,self._ctx)
if la_ == 1:
self.state = 395
self._errHandler.sync(self)
_la = self._input.LA(1)
if _la==73:
self.state = 394
self.subexpr()
self.state = 398
self._errHandler.sync(self)
_la = self._input.LA(1)
if _la==90:
self.state = 397
self.match(LaTeXParser.SINGLE_QUOTES)
pass
elif la_ == 2:
self.state = 401
self._errHandler.sync(self)
_la = self._input.LA(1)
if _la==90:
self.state = 400
self.match(LaTeXParser.SINGLE_QUOTES)
self.state = 404
self._errHandler.sync(self)
_la = self._input.LA(1)
if _la==73:
self.state = 403
self.subexpr()
pass
self.state = 408
self.match(LaTeXParser.L_PAREN)
self.state = 409
self.args()
self.state = 410
self.match(LaTeXParser.R_PAREN)
pass
elif token in [34]:
self.enterOuterAlt(localctx, 3)
self.state = 412
self.match(LaTeXParser.FUNC_INT)
self.state = 419
self._errHandler.sync(self)
token = self._input.LA(1)
if token in [73]:
self.state = 413
self.subexpr()
self.state = 414
self.supexpr()
pass
elif token in [74]:
self.state = 416
self.supexpr()
self.state = 417
self.subexpr()
pass
elif token in [15, 16, 19, 21, 23, 25, 27, 29, 30, 32, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 61, 63, 64, 68, 69, 70, 71, 72, 76, 77, 78, 91]:
pass
else:
pass
self.state = 427
self._errHandler.sync(self)
la_ = self._interp.adaptivePredict(self._input,49,self._ctx)
if la_ == 1:
self.state = 422
self._errHandler.sync(self)
la_ = self._interp.adaptivePredict(self._input,48,self._ctx)
if la_ == 1:
self.state = 421
self.additive(0)
self.state = 424
self.match(LaTeXParser.DIFFERENTIAL)
pass
elif la_ == 2:
self.state = 425
self.frac()
pass
elif la_ == 3:
self.state = 426
self.additive(0)
pass
pass
elif token in [63]:
self.enterOuterAlt(localctx, 4)
self.state = 429
self.match(LaTeXParser.FUNC_SQRT)
self.state = 434
self._errHandler.sync(self)
_la = self._input.LA(1)
if _la==25:
self.state = 430
self.match(LaTeXParser.L_BRACKET)
self.state = 431
localctx.root = self.expr()
self.state = 432
self.match(LaTeXParser.R_BRACKET)
self.state = 436
self.match(LaTeXParser.L_BRACE)
self.state = 437
localctx.base = self.expr()
self.state = 438
self.match(LaTeXParser.R_BRACE)
pass
elif token in [64]:
self.enterOuterAlt(localctx, 5)
self.state = 440
self.match(LaTeXParser.FUNC_OVERLINE)
self.state = 441
self.match(LaTeXParser.L_BRACE)
self.state = 442
localctx.base = self.expr()
self.state = 443
self.match(LaTeXParser.R_BRACE)
pass
elif token in [35, 36]:
self.enterOuterAlt(localctx, 6)
self.state = 445
_la = self._input.LA(1)
if not(_la==35 or _la==36):
self._errHandler.recoverInline(self)
else:
self._errHandler.reportMatch(self)
self.consume()
self.state = 452
self._errHandler.sync(self)
token = self._input.LA(1)
if token in [73]:
self.state = 446
self.subeq()
self.state = 447
self.supexpr()
pass
elif token in [74]:
self.state = 449
self.supexpr()
self.state = 450
self.subeq()
pass
else:
raise NoViableAltException(self)
self.state = 454
self.mp(0)
pass
elif token in [32]:
self.enterOuterAlt(localctx, 7)
self.state = 456
self.match(LaTeXParser.FUNC_LIM)
self.state = 457
self.limit_sub()
self.state = 458
self.mp(0)
pass
else:
raise NoViableAltException(self)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class ArgsContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def expr(self):
return self.getTypedRuleContext(LaTeXParser.ExprContext,0)
def args(self):
return self.getTypedRuleContext(LaTeXParser.ArgsContext,0)
def getRuleIndex(self):
return LaTeXParser.RULE_args
def args(self):
localctx = LaTeXParser.ArgsContext(self, self._ctx, self.state)
self.enterRule(localctx, 66, self.RULE_args)
try:
self.state = 467
self._errHandler.sync(self)
la_ = self._interp.adaptivePredict(self._input,53,self._ctx)
if la_ == 1:
self.enterOuterAlt(localctx, 1)
self.state = 462
self.expr()
self.state = 463
self.match(LaTeXParser.T__0)
self.state = 464
self.args()
pass
elif la_ == 2:
self.enterOuterAlt(localctx, 2)
self.state = 466
self.expr()
pass
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class Limit_subContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def UNDERSCORE(self):
return self.getToken(LaTeXParser.UNDERSCORE, 0)
def L_BRACE(self, i:int=None):
if i is None:
return self.getTokens(LaTeXParser.L_BRACE)
else:
return self.getToken(LaTeXParser.L_BRACE, i)
def LIM_APPROACH_SYM(self):
return self.getToken(LaTeXParser.LIM_APPROACH_SYM, 0)
def expr(self):
return self.getTypedRuleContext(LaTeXParser.ExprContext,0)
def R_BRACE(self, i:int=None):
if i is None:
return self.getTokens(LaTeXParser.R_BRACE)
else:
return self.getToken(LaTeXParser.R_BRACE, i)
def LETTER(self):
return self.getToken(LaTeXParser.LETTER, 0)
def SYMBOL(self):
return self.getToken(LaTeXParser.SYMBOL, 0)
def CARET(self):
return self.getToken(LaTeXParser.CARET, 0)
def ADD(self):
return self.getToken(LaTeXParser.ADD, 0)
def SUB(self):
return self.getToken(LaTeXParser.SUB, 0)
def getRuleIndex(self):
return LaTeXParser.RULE_limit_sub
def limit_sub(self):
localctx = LaTeXParser.Limit_subContext(self, self._ctx, self.state)
self.enterRule(localctx, 68, self.RULE_limit_sub)
self._la = 0 # Token type
try:
self.enterOuterAlt(localctx, 1)
self.state = 469
self.match(LaTeXParser.UNDERSCORE)
self.state = 470
self.match(LaTeXParser.L_BRACE)
self.state = 471
_la = self._input.LA(1)
if not(_la==77 or _la==91):
self._errHandler.recoverInline(self)
else:
self._errHandler.reportMatch(self)
self.consume()
self.state = 472
self.match(LaTeXParser.LIM_APPROACH_SYM)
self.state = 473
self.expr()
self.state = 482
self._errHandler.sync(self)
_la = self._input.LA(1)
if _la==74:
self.state = 474
self.match(LaTeXParser.CARET)
self.state = 480
self._errHandler.sync(self)
token = self._input.LA(1)
if token in [21]:
self.state = 475
self.match(LaTeXParser.L_BRACE)
self.state = 476
_la = self._input.LA(1)
if not(_la==15 or _la==16):
self._errHandler.recoverInline(self)
else:
self._errHandler.reportMatch(self)
self.consume()
self.state = 477
self.match(LaTeXParser.R_BRACE)
pass
elif token in [15]:
self.state = 478
self.match(LaTeXParser.ADD)
pass
elif token in [16]:
self.state = 479
self.match(LaTeXParser.SUB)
pass
else:
raise NoViableAltException(self)
self.state = 484
self.match(LaTeXParser.R_BRACE)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class Func_argContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def expr(self):
return self.getTypedRuleContext(LaTeXParser.ExprContext,0)
def func_arg(self):
return self.getTypedRuleContext(LaTeXParser.Func_argContext,0)
def getRuleIndex(self):
return LaTeXParser.RULE_func_arg
def func_arg(self):
localctx = LaTeXParser.Func_argContext(self, self._ctx, self.state)
self.enterRule(localctx, 70, self.RULE_func_arg)
try:
self.state = 491
self._errHandler.sync(self)
la_ = self._interp.adaptivePredict(self._input,56,self._ctx)
if la_ == 1:
self.enterOuterAlt(localctx, 1)
self.state = 486
self.expr()
pass
elif la_ == 2:
self.enterOuterAlt(localctx, 2)
self.state = 487
self.expr()
self.state = 488
self.match(LaTeXParser.T__0)
self.state = 489
self.func_arg()
pass
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class Func_arg_noparensContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def mp_nofunc(self):
return self.getTypedRuleContext(LaTeXParser.Mp_nofuncContext,0)
def getRuleIndex(self):
return LaTeXParser.RULE_func_arg_noparens
def func_arg_noparens(self):
localctx = LaTeXParser.Func_arg_noparensContext(self, self._ctx, self.state)
self.enterRule(localctx, 72, self.RULE_func_arg_noparens)
try:
self.enterOuterAlt(localctx, 1)
self.state = 493
self.mp_nofunc(0)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class SubexprContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def UNDERSCORE(self):
return self.getToken(LaTeXParser.UNDERSCORE, 0)
def atom(self):
return self.getTypedRuleContext(LaTeXParser.AtomContext,0)
def L_BRACE(self):
return self.getToken(LaTeXParser.L_BRACE, 0)
def expr(self):
return self.getTypedRuleContext(LaTeXParser.ExprContext,0)
def R_BRACE(self):
return self.getToken(LaTeXParser.R_BRACE, 0)
def getRuleIndex(self):
return LaTeXParser.RULE_subexpr
def subexpr(self):
localctx = LaTeXParser.SubexprContext(self, self._ctx, self.state)
self.enterRule(localctx, 74, self.RULE_subexpr)
try:
self.enterOuterAlt(localctx, 1)
self.state = 495
self.match(LaTeXParser.UNDERSCORE)
self.state = 501
self._errHandler.sync(self)
token = self._input.LA(1)
if token in [27, 29, 30, 68, 69, 70, 71, 72, 76, 77, 78, 91]:
self.state = 496
self.atom()
pass
elif token in [21]:
self.state = 497
self.match(LaTeXParser.L_BRACE)
self.state = 498
self.expr()
self.state = 499
self.match(LaTeXParser.R_BRACE)
pass
else:
raise NoViableAltException(self)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class SupexprContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def CARET(self):
return self.getToken(LaTeXParser.CARET, 0)
def atom(self):
return self.getTypedRuleContext(LaTeXParser.AtomContext,0)
def L_BRACE(self):
return self.getToken(LaTeXParser.L_BRACE, 0)
def expr(self):
return self.getTypedRuleContext(LaTeXParser.ExprContext,0)
def R_BRACE(self):
return self.getToken(LaTeXParser.R_BRACE, 0)
def getRuleIndex(self):
return LaTeXParser.RULE_supexpr
def supexpr(self):
localctx = LaTeXParser.SupexprContext(self, self._ctx, self.state)
self.enterRule(localctx, 76, self.RULE_supexpr)
try:
self.enterOuterAlt(localctx, 1)
self.state = 503
self.match(LaTeXParser.CARET)
self.state = 509
self._errHandler.sync(self)
token = self._input.LA(1)
if token in [27, 29, 30, 68, 69, 70, 71, 72, 76, 77, 78, 91]:
self.state = 504
self.atom()
pass
elif token in [21]:
self.state = 505
self.match(LaTeXParser.L_BRACE)
self.state = 506
self.expr()
self.state = 507
self.match(LaTeXParser.R_BRACE)
pass
else:
raise NoViableAltException(self)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class SubeqContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def UNDERSCORE(self):
return self.getToken(LaTeXParser.UNDERSCORE, 0)
def L_BRACE(self):
return self.getToken(LaTeXParser.L_BRACE, 0)
def equality(self):
return self.getTypedRuleContext(LaTeXParser.EqualityContext,0)
def R_BRACE(self):
return self.getToken(LaTeXParser.R_BRACE, 0)
def getRuleIndex(self):
return LaTeXParser.RULE_subeq
def subeq(self):
localctx = LaTeXParser.SubeqContext(self, self._ctx, self.state)
self.enterRule(localctx, 78, self.RULE_subeq)
try:
self.enterOuterAlt(localctx, 1)
self.state = 511
self.match(LaTeXParser.UNDERSCORE)
self.state = 512
self.match(LaTeXParser.L_BRACE)
self.state = 513
self.equality()
self.state = 514
self.match(LaTeXParser.R_BRACE)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
class SupeqContext(ParserRuleContext):
__slots__ = 'parser'
def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
super().__init__(parent, invokingState)
self.parser = parser
def UNDERSCORE(self):
return self.getToken(LaTeXParser.UNDERSCORE, 0)
def L_BRACE(self):
return self.getToken(LaTeXParser.L_BRACE, 0)
def equality(self):
return self.getTypedRuleContext(LaTeXParser.EqualityContext,0)
def R_BRACE(self):
return self.getToken(LaTeXParser.R_BRACE, 0)
def getRuleIndex(self):
return LaTeXParser.RULE_supeq
def supeq(self):
localctx = LaTeXParser.SupeqContext(self, self._ctx, self.state)
self.enterRule(localctx, 80, self.RULE_supeq)
try:
self.enterOuterAlt(localctx, 1)
self.state = 516
self.match(LaTeXParser.UNDERSCORE)
self.state = 517
self.match(LaTeXParser.L_BRACE)
self.state = 518
self.equality()
self.state = 519
self.match(LaTeXParser.R_BRACE)
except RecognitionException as re:
localctx.exception = re
self._errHandler.reportError(self, re)
self._errHandler.recover(self, re)
finally:
self.exitRule()
return localctx
def sempred(self, localctx:RuleContext, ruleIndex:int, predIndex:int):
if self._predicates == None:
self._predicates = dict()
self._predicates[1] = self.relation_sempred
self._predicates[4] = self.additive_sempred
self._predicates[5] = self.mp_sempred
self._predicates[6] = self.mp_nofunc_sempred
self._predicates[15] = self.exp_sempred
self._predicates[16] = self.exp_nofunc_sempred
pred = self._predicates.get(ruleIndex, None)
if pred is None:
raise Exception("No predicate with index:" + str(ruleIndex))
else:
return pred(localctx, predIndex)
def relation_sempred(self, localctx:RelationContext, predIndex:int):
if predIndex == 0:
return self.precpred(self._ctx, 2)
def additive_sempred(self, localctx:AdditiveContext, predIndex:int):
if predIndex == 1:
return self.precpred(self._ctx, 2)
def mp_sempred(self, localctx:MpContext, predIndex:int):
if predIndex == 2:
return self.precpred(self._ctx, 2)
def mp_nofunc_sempred(self, localctx:Mp_nofuncContext, predIndex:int):
if predIndex == 3:
return self.precpred(self._ctx, 2)
def exp_sempred(self, localctx:ExpContext, predIndex:int):
if predIndex == 4:
return self.precpred(self._ctx, 2)
def exp_nofunc_sempred(self, localctx:Exp_nofuncContext, predIndex:int):
if predIndex == 5:
return self.precpred(self._ctx, 2)
PK ]ZZZ�J�#x x $ sympy/parsing/latex/lark/__init__.pyfrom .latex_parser import parse_latex_lark, LarkLaTeXParser # noqa
from .transformer import TransformToSymPyExpr # noqa
PK ]ZZZ�%A�i i ( sympy/parsing/latex/lark/latex_parser.pyimport os
import logging
import re
from sympy.external import import_module
from sympy.parsing.latex.lark.transformer import TransformToSymPyExpr
_lark = import_module("lark")
class LarkLaTeXParser:
r"""Class for converting input `\mathrm{\LaTeX}` strings into SymPy Expressions.
It holds all the necessary internal data for doing so, and exposes hooks for
customizing its behavior.
Parameters
==========
print_debug_output : bool, optional
If set to ``True``, prints debug output to the logger. Defaults to ``False``.
transform : bool, optional
If set to ``True``, the class runs the Transformer class on the parse tree
generated by running ``Lark.parse`` on the input string. Defaults to ``True``.
Setting it to ``False`` can help with debugging the `\mathrm{\LaTeX}` grammar.
grammar_file : str, optional
The path to the grammar file that the parser should use. If set to ``None``,
it uses the default grammar, which is in ``grammar/latex.lark``, relative to
the ``sympy/parsing/latex/lark/`` directory.
transformer : str, optional
The name of the Transformer class to use. If set to ``None``, it uses the
default transformer class, which is :py:func:`TransformToSymPyExpr`.
"""
def __init__(self, print_debug_output=False, transform=True, grammar_file=None, transformer=None):
grammar_dir_path = os.path.join(os.path.dirname(__file__), "grammar/")
if grammar_file is None:
with open(os.path.join(grammar_dir_path, "latex.lark"), encoding="utf-8") as f:
latex_grammar = f.read()
else:
with open(grammar_file, encoding="utf-8") as f:
latex_grammar = f.read()
self.parser = _lark.Lark(
latex_grammar,
source_path=grammar_dir_path,
parser="earley",
start="latex_string",
lexer="auto",
ambiguity="explicit",
propagate_positions=False,
maybe_placeholders=False,
keep_all_tokens=True)
self.print_debug_output = print_debug_output
self.transform_expr = transform
if transformer is None:
self.transformer = TransformToSymPyExpr()
else:
self.transformer = transformer()
def doparse(self, s: str):
if self.print_debug_output:
_lark.logger.setLevel(logging.DEBUG)
parse_tree = self.parser.parse(s)
if not self.transform_expr:
# exit early and return the parse tree
_lark.logger.debug("expression = %s", s)
_lark.logger.debug(parse_tree)
_lark.logger.debug(parse_tree.pretty())
return parse_tree
if self.print_debug_output:
# print this stuff before attempting to run the transformer
_lark.logger.debug("expression = %s", s)
# print the `parse_tree` variable
_lark.logger.debug(parse_tree.pretty())
sympy_expression = self.transformer.transform(parse_tree)
if self.print_debug_output:
_lark.logger.debug("SymPy expression = %s", sympy_expression)
return sympy_expression
if _lark is not None:
_lark_latex_parser = LarkLaTeXParser()
def parse_latex_lark(s: str):
"""
Experimental LaTeX parser using Lark.
This function is still under development and its API may change with the
next releases of SymPy.
"""
if _lark is None:
raise ImportError("Lark is probably not installed")
return _lark_latex_parser.doparse(s)
def _pretty_print_lark_trees(tree, indent=0, show_expr=True):
if isinstance(tree, _lark.Token):
return tree.value
data = str(tree.data)
is_expr = data.startswith("expression")
if is_expr:
data = re.sub(r"^expression", "E", data)
is_ambig = (data == "_ambig")
if is_ambig:
new_indent = indent + 2
else:
new_indent = indent
output = ""
show_node = not is_expr or show_expr
if show_node:
output += str(data) + "("
if is_ambig:
output += "\n" + "\n".join([" " * new_indent + _pretty_print_lark_trees(i, new_indent, show_expr) for i in tree.children])
else:
output += ",".join([_pretty_print_lark_trees(i, new_indent, show_expr) for i in tree.children])
if show_node:
output += ")"
return output
PK ]ZZZ0�,�YM YM ' sympy/parsing/latex/lark/transformer.pyimport re
import sympy
from sympy.external import import_module
from sympy.parsing.latex.errors import LaTeXParsingError
lark = import_module("lark")
if lark:
from lark import Transformer, Token # type: ignore
else:
class Transformer: # type: ignore
def transform(self, *args):
pass
class Token: # type: ignore
pass
# noinspection PyPep8Naming,PyMethodMayBeStatic
class TransformToSymPyExpr(Transformer):
"""Returns a SymPy expression that is generated by traversing the ``lark.Tree``
passed to the ``.transform()`` function.
Notes
=====
**This class is never supposed to be used directly.**
In order to tweak the behavior of this class, it has to be subclassed and then after
the required modifications are made, the name of the new class should be passed to
the :py:class:`LarkLaTeXParser` class by using the ``transformer`` argument in the
constructor.
Parameters
==========
visit_tokens : bool, optional
For information about what this option does, see `here
<https://lark-parser.readthedocs.io/en/latest/visitors.html#lark.visitors.Transformer>`_.
Note that the option must be set to ``True`` for the default parser to work.
"""
SYMBOL = sympy.Symbol
DIGIT = sympy.core.numbers.Integer
def CMD_INFTY(self, tokens):
return sympy.oo
def GREEK_SYMBOL(self, tokens):
# we omit the first character because it is a backslash. Also, if the variable name has "var" in it,
# like "varphi" or "varepsilon", we remove that too
variable_name = re.sub("var", "", tokens[1:])
return sympy.Symbol(variable_name)
def BASIC_SUBSCRIPTED_SYMBOL(self, tokens):
symbol, sub = tokens.value.split("_")
if sub.startswith("{"):
return sympy.Symbol("%s_{%s}" % (symbol, sub[1:-1]))
else:
return sympy.Symbol("%s_{%s}" % (symbol, sub))
def GREEK_SUBSCRIPTED_SYMBOL(self, tokens):
greek_letter, sub = tokens.value.split("_")
greek_letter = re.sub("var", "", greek_letter[1:])
if sub.startswith("{"):
return sympy.Symbol("%s_{%s}" % (greek_letter, sub[1:-1]))
else:
return sympy.Symbol("%s_{%s}" % (greek_letter, sub))
def SYMBOL_WITH_GREEK_SUBSCRIPT(self, tokens):
symbol, sub = tokens.value.split("_")
if sub.startswith("{"):
greek_letter = sub[2:-1]
greek_letter = re.sub("var", "", greek_letter)
return sympy.Symbol("%s_{%s}" % (symbol, greek_letter))
else:
greek_letter = sub[1:]
greek_letter = re.sub("var", "", greek_letter)
return sympy.Symbol("%s_{%s}" % (symbol, greek_letter))
def multi_letter_symbol(self, tokens):
return sympy.Symbol(tokens[2])
def number(self, tokens):
if "." in tokens[0]:
return sympy.core.numbers.Float(tokens[0])
else:
return sympy.core.numbers.Integer(tokens[0])
def latex_string(self, tokens):
return tokens[0]
def group_round_parentheses(self, tokens):
return tokens[1]
def group_square_brackets(self, tokens):
return tokens[1]
def group_curly_parentheses(self, tokens):
return tokens[1]
def eq(self, tokens):
return sympy.Eq(tokens[0], tokens[2])
def ne(self, tokens):
return sympy.Ne(tokens[0], tokens[2])
def lt(self, tokens):
return sympy.Lt(tokens[0], tokens[2])
def lte(self, tokens):
return sympy.Le(tokens[0], tokens[2])
def gt(self, tokens):
return sympy.Gt(tokens[0], tokens[2])
def gte(self, tokens):
return sympy.Ge(tokens[0], tokens[2])
def add(self, tokens):
return sympy.Add(tokens[0], tokens[2])
def sub(self, tokens):
if len(tokens) == 2:
return -tokens[1]
elif len(tokens) == 3:
return sympy.Add(tokens[0], -tokens[2])
def mul(self, tokens):
return sympy.Mul(tokens[0], tokens[2])
def div(self, tokens):
return sympy.Mul(tokens[0], sympy.Pow(tokens[2], -1))
def adjacent_expressions(self, tokens):
# Most of the time, if two expressions are next to each other, it means implicit multiplication,
# but not always
from sympy.physics.quantum import Bra, Ket
if isinstance(tokens[0], Ket) and isinstance(tokens[1], Bra):
from sympy.physics.quantum import OuterProduct
return OuterProduct(tokens[0], tokens[1])
elif tokens[0] == sympy.Symbol("d"):
# If the leftmost token is a "d", then it is highly likely that this is a differential
return tokens[0], tokens[1]
elif isinstance(tokens[0], tuple):
# then we have a derivative
return sympy.Derivative(tokens[1], tokens[0][1])
else:
return sympy.Mul(tokens[0], tokens[1])
def superscript(self, tokens):
return sympy.Pow(tokens[0], tokens[2])
def fraction(self, tokens):
numerator = tokens[1]
if isinstance(tokens[2], tuple):
# we only need the variable w.r.t. which we are differentiating
_, variable = tokens[2]
# we will pass this information upwards
return "derivative", variable
else:
denominator = tokens[2]
return sympy.Mul(numerator, sympy.Pow(denominator, -1))
def binomial(self, tokens):
return sympy.binomial(tokens[1], tokens[2])
def normal_integral(self, tokens):
underscore_index = None
caret_index = None
if "_" in tokens:
# we need to know the index because the next item in the list is the
# arguments for the lower bound of the integral
underscore_index = tokens.index("_")
if "^" in tokens:
# we need to know the index because the next item in the list is the
# arguments for the upper bound of the integral
caret_index = tokens.index("^")
lower_bound = tokens[underscore_index + 1] if underscore_index else None
upper_bound = tokens[caret_index + 1] if caret_index else None
differential_symbol = self._extract_differential_symbol(tokens)
if differential_symbol is None:
raise LaTeXParsingError("Differential symbol was not found in the expression."
"Valid differential symbols are \"d\", \"\\text{d}, and \"\\mathrm{d}\".")
# else we can assume that a differential symbol was found
differential_variable_index = tokens.index(differential_symbol) + 1
differential_variable = tokens[differential_variable_index]
# we can't simply do something like `if (lower_bound and not upper_bound) ...` because this would
# evaluate to `True` if the `lower_bound` is 0 and upper bound is non-zero
if lower_bound is not None and upper_bound is None:
# then one was given and the other wasn't
raise LaTeXParsingError("Lower bound for the integral was found, but upper bound was not found.")
if upper_bound is not None and lower_bound is None:
# then one was given and the other wasn't
raise LaTeXParsingError("Upper bound for the integral was found, but lower bound was not found.")
# check if any expression was given or not. If it wasn't, then set the integrand to 1.
if underscore_index is not None and underscore_index == differential_variable_index - 3:
# The Token at differential_variable_index - 2 should be the integrand. However, if going one more step
# backwards after that gives us the underscore, then that means that there _was_ no integrand.
# Example: \int^7_0 dx
integrand = 1
elif caret_index is not None and caret_index == differential_variable_index - 3:
# The Token at differential_variable_index - 2 should be the integrand. However, if going one more step
# backwards after that gives us the caret, then that means that there _was_ no integrand.
# Example: \int_0^7 dx
integrand = 1
elif differential_variable_index == 2:
# this means we have something like "\int dx", because the "\int" symbol will always be
# at index 0 in `tokens`
integrand = 1
else:
# The Token at differential_variable_index - 1 is the differential symbol itself, so we need to go one
# more step before that.
integrand = tokens[differential_variable_index - 2]
if lower_bound is not None:
# then we have a definite integral
# we can assume that either both the lower and upper bounds are given, or
# neither of them are
return sympy.Integral(integrand, (differential_variable, lower_bound, upper_bound))
else:
# we have an indefinite integral
return sympy.Integral(integrand, differential_variable)
def group_curly_parentheses_int(self, tokens):
# return signature is a tuple consisting of the expression in the numerator, along with the variable of
# integration
if len(tokens) == 3:
return 1, tokens[1]
elif len(tokens) == 4:
return tokens[1], tokens[2]
# there are no other possibilities
def special_fraction(self, tokens):
numerator, variable = tokens[1]
denominator = tokens[2]
# We pass the integrand, along with information about the variable of integration, upw
return sympy.Mul(numerator, sympy.Pow(denominator, -1)), variable
def integral_with_special_fraction(self, tokens):
underscore_index = None
caret_index = None
if "_" in tokens:
# we need to know the index because the next item in the list is the
# arguments for the lower bound of the integral
underscore_index = tokens.index("_")
if "^" in tokens:
# we need to know the index because the next item in the list is the
# arguments for the upper bound of the integral
caret_index = tokens.index("^")
lower_bound = tokens[underscore_index + 1] if underscore_index else None
upper_bound = tokens[caret_index + 1] if caret_index else None
# we can't simply do something like `if (lower_bound and not upper_bound) ...` because this would
# evaluate to `True` if the `lower_bound` is 0 and upper bound is non-zero
if lower_bound is not None and upper_bound is None:
# then one was given and the other wasn't
raise LaTeXParsingError("Lower bound for the integral was found, but upper bound was not found.")
if upper_bound is not None and lower_bound is None:
# then one was given and the other wasn't
raise LaTeXParsingError("Upper bound for the integral was found, but lower bound was not found.")
integrand, differential_variable = tokens[-1]
if lower_bound is not None:
# then we have a definite integral
# we can assume that either both the lower and upper bounds are given, or
# neither of them are
return sympy.Integral(integrand, (differential_variable, lower_bound, upper_bound))
else:
# we have an indefinite integral
return sympy.Integral(integrand, differential_variable)
def group_curly_parentheses_special(self, tokens):
underscore_index = tokens.index("_")
caret_index = tokens.index("^")
# given the type of expressions we are parsing, we can assume that the lower limit
# will always use braces around its arguments. This is because we don't support
# converting unconstrained sums into SymPy expressions.
# first we isolate the bottom limit
left_brace_index = tokens.index("{", underscore_index)
right_brace_index = tokens.index("}", underscore_index)
bottom_limit = tokens[left_brace_index + 1: right_brace_index]
# next, we isolate the upper limit
top_limit = tokens[caret_index + 1:]
# the code below will be useful for supporting things like `\sum_{n = 0}^{n = 5} n^2`
# if "{" in top_limit:
# left_brace_index = tokens.index("{", caret_index)
# if left_brace_index != -1:
# # then there's a left brace in the string, and we need to find the closing right brace
# right_brace_index = tokens.index("}", caret_index)
# top_limit = tokens[left_brace_index + 1: right_brace_index]
# print(f"top limit = {top_limit}")
index_variable = bottom_limit[0]
lower_limit = bottom_limit[-1]
upper_limit = top_limit[0] # for now, the index will always be 0
# print(f"return value = ({index_variable}, {lower_limit}, {upper_limit})")
return index_variable, lower_limit, upper_limit
def summation(self, tokens):
return sympy.Sum(tokens[2], tokens[1])
def product(self, tokens):
return sympy.Product(tokens[2], tokens[1])
def limit_dir_expr(self, tokens):
caret_index = tokens.index("^")
if "{" in tokens:
left_curly_brace_index = tokens.index("{", caret_index)
direction = tokens[left_curly_brace_index + 1]
else:
direction = tokens[caret_index + 1]
if direction == "+":
return tokens[0], "+"
elif direction == "-":
return tokens[0], "-"
else:
return tokens[0], "+-"
def group_curly_parentheses_lim(self, tokens):
limit_variable = tokens[1]
if isinstance(tokens[3], tuple):
destination, direction = tokens[3]
else:
destination = tokens[3]
direction = "+-"
return limit_variable, destination, direction
def limit(self, tokens):
limit_variable, destination, direction = tokens[2]
return sympy.Limit(tokens[-1], limit_variable, destination, direction)
def differential(self, tokens):
return tokens[1]
def derivative(self, tokens):
return sympy.Derivative(tokens[-1], tokens[5])
def list_of_expressions(self, tokens):
if len(tokens) == 1:
# we return it verbatim because the function_applied node expects
# a list
return tokens
else:
def remove_tokens(args):
if isinstance(args, Token):
if args.type != "COMMA":
# An unexpected token was encountered
raise LaTeXParsingError("A comma token was expected, but some other token was encountered.")
return False
return True
return filter(remove_tokens, tokens)
def function_applied(self, tokens):
return sympy.Function(tokens[0])(*tokens[2])
def min(self, tokens):
return sympy.Min(*tokens[2])
def max(self, tokens):
return sympy.Max(*tokens[2])
def bra(self, tokens):
from sympy.physics.quantum import Bra
return Bra(tokens[1])
def ket(self, tokens):
from sympy.physics.quantum import Ket
return Ket(tokens[1])
def inner_product(self, tokens):
from sympy.physics.quantum import Bra, Ket, InnerProduct
return InnerProduct(Bra(tokens[1]), Ket(tokens[3]))
def sin(self, tokens):
return sympy.sin(tokens[1])
def cos(self, tokens):
return sympy.cos(tokens[1])
def tan(self, tokens):
return sympy.tan(tokens[1])
def csc(self, tokens):
return sympy.csc(tokens[1])
def sec(self, tokens):
return sympy.sec(tokens[1])
def cot(self, tokens):
return sympy.cot(tokens[1])
def sin_power(self, tokens):
exponent = tokens[2]
if exponent == -1:
return sympy.asin(tokens[-1])
else:
return sympy.Pow(sympy.sin(tokens[-1]), exponent)
def cos_power(self, tokens):
exponent = tokens[2]
if exponent == -1:
return sympy.acos(tokens[-1])
else:
return sympy.Pow(sympy.cos(tokens[-1]), exponent)
def tan_power(self, tokens):
exponent = tokens[2]
if exponent == -1:
return sympy.atan(tokens[-1])
else:
return sympy.Pow(sympy.tan(tokens[-1]), exponent)
def csc_power(self, tokens):
exponent = tokens[2]
if exponent == -1:
return sympy.acsc(tokens[-1])
else:
return sympy.Pow(sympy.csc(tokens[-1]), exponent)
def sec_power(self, tokens):
exponent = tokens[2]
if exponent == -1:
return sympy.asec(tokens[-1])
else:
return sympy.Pow(sympy.sec(tokens[-1]), exponent)
def cot_power(self, tokens):
exponent = tokens[2]
if exponent == -1:
return sympy.acot(tokens[-1])
else:
return sympy.Pow(sympy.cot(tokens[-1]), exponent)
def arcsin(self, tokens):
return sympy.asin(tokens[1])
def arccos(self, tokens):
return sympy.acos(tokens[1])
def arctan(self, tokens):
return sympy.atan(tokens[1])
def arccsc(self, tokens):
return sympy.acsc(tokens[1])
def arcsec(self, tokens):
return sympy.asec(tokens[1])
def arccot(self, tokens):
return sympy.acot(tokens[1])
def sinh(self, tokens):
return sympy.sinh(tokens[1])
def cosh(self, tokens):
return sympy.cosh(tokens[1])
def tanh(self, tokens):
return sympy.tanh(tokens[1])
def asinh(self, tokens):
return sympy.asinh(tokens[1])
def acosh(self, tokens):
return sympy.acosh(tokens[1])
def atanh(self, tokens):
return sympy.atanh(tokens[1])
def abs(self, tokens):
return sympy.Abs(tokens[1])
def floor(self, tokens):
return sympy.floor(tokens[1])
def ceil(self, tokens):
return sympy.ceiling(tokens[1])
def factorial(self, tokens):
return sympy.factorial(tokens[0])
def conjugate(self, tokens):
return sympy.conjugate(tokens[1])
def square_root(self, tokens):
if len(tokens) == 2:
# then there was no square bracket argument
return sympy.sqrt(tokens[1])
elif len(tokens) == 3:
# then there _was_ a square bracket argument
return sympy.root(tokens[2], tokens[1])
def exponential(self, tokens):
return sympy.exp(tokens[1])
def log(self, tokens):
if tokens[0].type == "FUNC_LG":
# we don't need to check if there's an underscore or not because having one
# in this case would be meaningless
# TODO: ANTLR refers to ISO 80000-2:2019. should we keep base 10 or base 2?
return sympy.log(tokens[1], 10)
elif tokens[0].type == "FUNC_LN":
return sympy.log(tokens[1])
elif tokens[0].type == "FUNC_LOG":
# we check if a base was specified or not
if "_" in tokens:
# then a base was specified
return sympy.log(tokens[3], tokens[2])
else:
# a base was not specified
return sympy.log(tokens[1])
def _extract_differential_symbol(self, s: str):
differential_symbols = {"d", r"\text{d}", r"\mathrm{d}"}
differential_symbol = next((symbol for symbol in differential_symbols if symbol in s), None)
return differential_symbol
PK ]ZZZ�L�� � 3 sympy/parsing/latex/lark/grammar/greek_symbols.lark// Greek symbols
// TODO: Shouold we include the uppercase variants for the symbols where the uppercase variant doesn't have a separate meaning?
ALPHA: "\\alpha"
BETA: "\\beta"
GAMMA: "\\gamma"
DELTA: "\\delta" // TODO: Should this be included? Delta usually denotes other things.
EPSILON: "\\epsilon" | "\\varepsilon"
ZETA: "\\zeta"
ETA: "\\eta"
THETA: "\\theta" | "\\vartheta"
// TODO: Should I add iota to the list?
KAPPA: "\\kappa"
LAMBDA: "\\lambda" // TODO: What about the uppercase variant?
MU: "\\mu"
NU: "\\nu"
XI: "\\xi"
// TODO: Should there be a separate note for transforming \pi into sympy.pi?
RHO: "\\rho" | "\\varrho"
// TODO: What should we do about sigma?
TAU: "\\tau"
UPSILON: "\\upsilon"
PHI: "\\phi" | "\\varphi"
CHI: "\\chi"
PSI: "\\psi"
OMEGA: "\\omega"
GREEK_SYMBOL: ALPHA | BETA | GAMMA | DELTA | EPSILON | ZETA | ETA | THETA | KAPPA
| LAMBDA | MU | NU | XI | RHO | TAU | UPSILON | PHI | CHI | PSI | OMEGA
PK ]ZZZ<B��% �% + sympy/parsing/latex/lark/grammar/latex.lark%ignore /[ \t\n\r]+/
%ignore "\\," | "\\thinspace" | "\\:" | "\\medspace" | "\\;" | "\\thickspace"
%ignore "\\quad" | "\\qquad"
%ignore "\\!" | "\\negthinspace" | "\\negmedspace" | "\\negthickspace"
%ignore "\\vrule" | "\\vcenter" | "\\vbox" | "\\vskip" | "\\vspace" | "\\hfill"
%ignore "\\*" | "\\-" | "\\." | "\\/" | "\\\\" | "\\(" | "\\="
%ignore "\\left" | "\\right"
%ignore "\\limits" | "\\nolimits"
%ignore "\\displaystyle"
///////////////////// tokens ///////////////////////
// basic binary operators
ADD: "+"
SUB: "-"
MUL: "*"
DIV: "/"
// tokens with distinct left and right symbols
L_BRACE: "{"
R_BRACE: "}"
L_BRACE_LITERAL: "\\{"
R_BRACE_LITERAL: "\\}"
L_BRACKET: "["
R_BRACKET: "]"
L_CEIL: "\\lceil"
R_CEIL: "\\rceil"
L_FLOOR: "\\lfloor"
R_FLOOR: "\\rfloor"
L_PAREN: "("
R_PAREN: ")"
// limit, integral, sum, and product symbols
FUNC_LIM: "\\lim"
LIM_APPROACH_SYM: "\\to" | "\\rightarrow" | "\\Rightarrow" | "\\longrightarrow" | "\\Longrightarrow"
FUNC_INT: "\\int" | "\\intop"
FUNC_SUM: "\\sum"
FUNC_PROD: "\\prod"
// common functions
FUNC_EXP: "\\exp"
FUNC_LOG: "\\log"
FUNC_LN: "\\ln"
FUNC_LG: "\\lg"
FUNC_MIN: "\\min"
FUNC_MAX: "\\max"
// trigonometric functions
FUNC_SIN: "\\sin"
FUNC_COS: "\\cos"
FUNC_TAN: "\\tan"
FUNC_CSC: "\\csc"
FUNC_SEC: "\\sec"
FUNC_COT: "\\cot"
// inverse trigonometric functions
FUNC_ARCSIN: "\\arcsin"
FUNC_ARCCOS: "\\arccos"
FUNC_ARCTAN: "\\arctan"
FUNC_ARCCSC: "\\arccsc"
FUNC_ARCSEC: "\\arcsec"
FUNC_ARCCOT: "\\arccot"
// hyperbolic trigonometric functions
FUNC_SINH: "\\sinh"
FUNC_COSH: "\\cosh"
FUNC_TANH: "\\tanh"
FUNC_ARSINH: "\\arsinh"
FUNC_ARCOSH: "\\arcosh"
FUNC_ARTANH: "\\artanh"
FUNC_SQRT: "\\sqrt"
// miscellaneous symbols
CMD_TIMES: "\\times"
CMD_CDOT: "\\cdot"
CMD_DIV: "\\div"
CMD_FRAC: "\\frac" | "\\dfrac" | "\\tfrac" | "\\nicefrac"
CMD_BINOM: "\\binom" | "\\dbinom" | "\\tbinom"
CMD_OVERLINE: "\\overline"
CMD_LANGLE: "\\langle"
CMD_RANGLE: "\\rangle"
CMD_MATHIT: "\\mathit"
CMD_INFTY: "\\infty"
BANG: "!"
BAR: "|"
CARET: "^"
COLON: ":"
UNDERSCORE: "_"
// relational symbols
EQUAL: "="
NOT_EQUAL: "\\neq" | "\\ne"
LT: "<"
LTE: "\\leq" | "\\le" | "\\leqslant"
GT: ">"
GTE: "\\geq" | "\\ge" | "\\geqslant"
DIV_SYMBOL: CMD_DIV | DIV
MUL_SYMBOL: MUL | CMD_TIMES | CMD_CDOT
%import .greek_symbols.GREEK_SYMBOL
UPRIGHT_DIFFERENTIAL_SYMBOL: "\\text{d}" | "\\mathrm{d}"
DIFFERENTIAL_SYMBOL: "d" | UPRIGHT_DIFFERENTIAL_SYMBOL
// disallow "d" as a variable name because we want to parse "d" as a differential symbol.
SYMBOL: /[a-zA-Z]/
BASIC_SUBSCRIPTED_SYMBOL: /([a-zA-Z])_(([A-Za-z0-9]|[a-zA-Z]+)|\{([A-Za-z0-9]|[a-zA-Z]+)\})/
SYMBOL_WITH_GREEK_SUBSCRIPT: /([a-zA-Z])_/ GREEK_SYMBOL | /([a-zA-Z])_/ L_BRACE GREEK_SYMBOL R_BRACE
// best to define the variant with braces like that instead of shoving it all into one case like in
// /([a-zA-Z])_/ L_BRACE? GREEK_SYMBOL R_BRACE? because then we can easily error out on input like
// r"h_{\theta"
GREEK_SUBSCRIPTED_SYMBOL: GREEK_SYMBOL /_(([A-Za-z0-9]|[a-zA-Z]+)|\{([A-Za-z0-9]|[a-zA-Z]+)\})/
%import common.DIGIT -> DIGIT
//////////////////// grammar //////////////////////
latex_string: _relation | _expression
_one_letter_symbol: SYMBOL
| BASIC_SUBSCRIPTED_SYMBOL
| SYMBOL_WITH_GREEK_SUBSCRIPT
| GREEK_SUBSCRIPTED_SYMBOL
| GREEK_SYMBOL
multi_letter_symbol: CMD_MATHIT L_BRACE /[a-zA-Z]+(\s+[a-zA-Z]+)*/ R_BRACE
number: /\d+(\.\d*)?/
_atomic_expr: _one_letter_symbol
| multi_letter_symbol
| number
| CMD_INFTY
group_round_parentheses: L_PAREN _expression R_PAREN
group_square_brackets: L_BRACKET _expression R_BRACKET
group_curly_parentheses: L_BRACE _expression R_BRACE
_relation: eq | ne | lt | lte | gt | gte
eq: _expression EQUAL _expression
ne: _expression NOT_EQUAL _expression
lt: _expression LT _expression
lte: _expression LTE _expression
gt: _expression GT _expression
gte: _expression GTE _expression
_expression_core: _atomic_expr | group_curly_parentheses
add: _expression ADD _expression_mul
sub: _expression SUB _expression_mul
| SUB _expression_mul
mul: _expression_mul MUL_SYMBOL _expression_power
div: _expression_mul DIV_SYMBOL _expression_power
adjacent_expressions: (_one_letter_symbol | number) _expression_mul
| group_round_parentheses (group_round_parentheses | _one_letter_symbol)
| _function _function
| fraction _expression
_expression_func: _expression_core
| group_round_parentheses
| fraction
| binomial
| _function
_expression_power: _expression_func | superscript
_expression_mul: _expression_power
| mul | div | adjacent_expressions
| _integral// | derivative
| summation | product
| limit
_expression: _expression_mul | add | sub
_limit_dir: "+" | "-" | L_BRACE ("+" | "-") R_BRACE
limit_dir_expr: _expression CARET _limit_dir
group_curly_parentheses_lim: L_BRACE _expression LIM_APPROACH_SYM (limit_dir_expr | _expression) R_BRACE
limit: FUNC_LIM UNDERSCORE group_curly_parentheses_lim _expression
differential: DIFFERENTIAL_SYMBOL _one_letter_symbol
//_derivative_operator: CMD_FRAC L_BRACE DIFFERENTIAL_SYMBOL R_BRACE L_BRACE differential R_BRACE
//derivative: _derivative_operator _expression
_integral: normal_integral | integral_with_special_fraction
normal_integral: FUNC_INT _expression DIFFERENTIAL_SYMBOL _one_letter_symbol
| FUNC_INT (CARET _expression_core UNDERSCORE _expression_core)? _expression? DIFFERENTIAL_SYMBOL _one_letter_symbol
| FUNC_INT (UNDERSCORE _expression_core CARET _expression_core)? _expression? DIFFERENTIAL_SYMBOL _one_letter_symbol
group_curly_parentheses_int: L_BRACE _expression? differential R_BRACE
special_fraction: CMD_FRAC group_curly_parentheses_int group_curly_parentheses
integral_with_special_fraction: FUNC_INT special_fraction
| FUNC_INT (CARET _expression_core UNDERSCORE _expression_core)? special_fraction
| FUNC_INT (UNDERSCORE _expression_core CARET _expression_core)? special_fraction
group_curly_parentheses_special: UNDERSCORE L_BRACE _atomic_expr EQUAL _atomic_expr R_BRACE CARET _expression_core
| CARET _expression_core UNDERSCORE L_BRACE _atomic_expr EQUAL _atomic_expr R_BRACE
summation: FUNC_SUM group_curly_parentheses_special _expression
| FUNC_SUM group_curly_parentheses_special _expression
product: FUNC_PROD group_curly_parentheses_special _expression
| FUNC_PROD group_curly_parentheses_special _expression
superscript: _expression_func CARET _expression_power
fraction: _basic_fraction
| _simple_fraction
| _general_fraction
_basic_fraction: CMD_FRAC DIGIT (DIGIT | SYMBOL | GREEK_SYMBOL)
_simple_fraction: CMD_FRAC DIGIT group_curly_parentheses
| CMD_FRAC group_curly_parentheses (DIGIT | SYMBOL | GREEK_SYMBOL)
_general_fraction: CMD_FRAC group_curly_parentheses group_curly_parentheses
binomial: _basic_binomial
| _simple_binomial
| _general_binomial
_basic_binomial: CMD_BINOM DIGIT (DIGIT | SYMBOL | GREEK_SYMBOL)
_simple_binomial: CMD_BINOM DIGIT group_curly_parentheses
| CMD_BINOM group_curly_parentheses (DIGIT | SYMBOL | GREEK_SYMBOL)
_general_binomial: CMD_BINOM group_curly_parentheses group_curly_parentheses
list_of_expressions: _expression ("," _expression)*
function_applied: _one_letter_symbol L_PAREN list_of_expressions R_PAREN
min: FUNC_MIN L_PAREN list_of_expressions R_PAREN
max: FUNC_MAX L_PAREN list_of_expressions R_PAREN
bra: CMD_LANGLE _expression BAR
ket: BAR _expression CMD_RANGLE
inner_product: CMD_LANGLE _expression BAR _expression CMD_RANGLE
_function: function_applied
| abs | floor | ceil
| _trigonometric_function | _inverse_trigonometric_function
| _trigonometric_function_power
| _hyperbolic_trigonometric_function | _inverse_hyperbolic_trigonometric_function
| exponential
| log
| square_root
| factorial
| conjugate
| max | min
| bra | ket | inner_product
exponential: FUNC_EXP _expression
log: FUNC_LOG _expression
| FUNC_LN _expression
| FUNC_LG _expression
| FUNC_LOG UNDERSCORE (DIGIT | _one_letter_symbol) _expression
| FUNC_LOG UNDERSCORE group_curly_parentheses _expression
square_root: FUNC_SQRT group_curly_parentheses
| FUNC_SQRT group_square_brackets group_curly_parentheses
factorial: _expression BANG
conjugate: CMD_OVERLINE group_curly_parentheses
| CMD_OVERLINE DIGIT
_trigonometric_function: sin | cos | tan | csc | sec | cot
sin: FUNC_SIN _expression
cos: FUNC_COS _expression
tan: FUNC_TAN _expression
csc: FUNC_CSC _expression
sec: FUNC_SEC _expression
cot: FUNC_COT _expression
_trigonometric_function_power: sin_power | cos_power | tan_power | csc_power | sec_power | cot_power
sin_power: FUNC_SIN CARET _expression_core _expression
cos_power: FUNC_COS CARET _expression_core _expression
tan_power: FUNC_TAN CARET _expression_core _expression
csc_power: FUNC_CSC CARET _expression_core _expression
sec_power: FUNC_SEC CARET _expression_core _expression
cot_power: FUNC_COT CARET _expression_core _expression
_hyperbolic_trigonometric_function: sinh | cosh | tanh
sinh: FUNC_SINH _expression
cosh: FUNC_COSH _expression
tanh: FUNC_TANH _expression
_inverse_trigonometric_function: arcsin | arccos | arctan | arccsc | arcsec | arccot
arcsin: FUNC_ARCSIN _expression
arccos: FUNC_ARCCOS _expression
arctan: FUNC_ARCTAN _expression
arccsc: FUNC_ARCCSC _expression
arcsec: FUNC_ARCSEC _expression
arccot: FUNC_ARCCOT _expression
_inverse_hyperbolic_trigonometric_function: asinh | acosh | atanh
asinh: FUNC_ARSINH _expression
acosh: FUNC_ARCOSH _expression
atanh: FUNC_ARTANH _expression
abs: BAR _expression BAR
floor: L_FLOOR _expression R_FLOOR
ceil: L_CEIL _expression R_CEIL
PK ]ZZZwV�� � sympy/physics/__init__.py"""
A module that helps solving problems in physics.
"""
from . import units
from .matrices import mgamma, msigma, minkowski_tensor, mdft
__all__ = [
'units',
'mgamma', 'msigma', 'minkowski_tensor', 'mdft',
]
PK ]ZZZ�w;� � sympy/physics/hydrogen.pyfrom sympy.core.numbers import Float
from sympy.core.singleton import S
from sympy.functions.combinatorial.factorials import factorial
from sympy.functions.elementary.exponential import exp
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.special.polynomials import assoc_laguerre
from sympy.functions.special.spherical_harmonics import Ynm
def R_nl(n, l, r, Z=1):
"""
Returns the Hydrogen radial wavefunction R_{nl}.
Parameters
==========
n : integer
Principal Quantum Number which is
an integer with possible values as 1, 2, 3, 4,...
l : integer
``l`` is the Angular Momentum Quantum Number with
values ranging from 0 to ``n-1``.
r :
Radial coordinate.
Z :
Atomic number (1 for Hydrogen, 2 for Helium, ...)
Everything is in Hartree atomic units.
Examples
========
>>> from sympy.physics.hydrogen import R_nl
>>> from sympy.abc import r, Z
>>> R_nl(1, 0, r, Z)
2*sqrt(Z**3)*exp(-Z*r)
>>> R_nl(2, 0, r, Z)
sqrt(2)*(-Z*r + 2)*sqrt(Z**3)*exp(-Z*r/2)/4
>>> R_nl(2, 1, r, Z)
sqrt(6)*Z*r*sqrt(Z**3)*exp(-Z*r/2)/12
For Hydrogen atom, you can just use the default value of Z=1:
>>> R_nl(1, 0, r)
2*exp(-r)
>>> R_nl(2, 0, r)
sqrt(2)*(2 - r)*exp(-r/2)/4
>>> R_nl(3, 0, r)
2*sqrt(3)*(2*r**2/9 - 2*r + 3)*exp(-r/3)/27
For Silver atom, you would use Z=47:
>>> R_nl(1, 0, r, Z=47)
94*sqrt(47)*exp(-47*r)
>>> R_nl(2, 0, r, Z=47)
47*sqrt(94)*(2 - 47*r)*exp(-47*r/2)/4
>>> R_nl(3, 0, r, Z=47)
94*sqrt(141)*(4418*r**2/9 - 94*r + 3)*exp(-47*r/3)/27
The normalization of the radial wavefunction is:
>>> from sympy import integrate, oo
>>> integrate(R_nl(1, 0, r)**2 * r**2, (r, 0, oo))
1
>>> integrate(R_nl(2, 0, r)**2 * r**2, (r, 0, oo))
1
>>> integrate(R_nl(2, 1, r)**2 * r**2, (r, 0, oo))
1
It holds for any atomic number:
>>> integrate(R_nl(1, 0, r, Z=2)**2 * r**2, (r, 0, oo))
1
>>> integrate(R_nl(2, 0, r, Z=3)**2 * r**2, (r, 0, oo))
1
>>> integrate(R_nl(2, 1, r, Z=4)**2 * r**2, (r, 0, oo))
1
"""
# sympify arguments
n, l, r, Z = map(S, [n, l, r, Z])
# radial quantum number
n_r = n - l - 1
# rescaled "r"
a = 1/Z # Bohr radius
r0 = 2 * r / (n * a)
# normalization coefficient
C = sqrt((S(2)/(n*a))**3 * factorial(n_r) / (2*n*factorial(n + l)))
# This is an equivalent normalization coefficient, that can be found in
# some books. Both coefficients seem to be the same fast:
# C = S(2)/n**2 * sqrt(1/a**3 * factorial(n_r) / (factorial(n+l)))
return C * r0**l * assoc_laguerre(n_r, 2*l + 1, r0).expand() * exp(-r0/2)
def Psi_nlm(n, l, m, r, phi, theta, Z=1):
"""
Returns the Hydrogen wave function psi_{nlm}. It's the product of
the radial wavefunction R_{nl} and the spherical harmonic Y_{l}^{m}.
Parameters
==========
n : integer
Principal Quantum Number which is
an integer with possible values as 1, 2, 3, 4,...
l : integer
``l`` is the Angular Momentum Quantum Number with
values ranging from 0 to ``n-1``.
m : integer
``m`` is the Magnetic Quantum Number with values
ranging from ``-l`` to ``l``.
r :
radial coordinate
phi :
azimuthal angle
theta :
polar angle
Z :
atomic number (1 for Hydrogen, 2 for Helium, ...)
Everything is in Hartree atomic units.
Examples
========
>>> from sympy.physics.hydrogen import Psi_nlm
>>> from sympy import Symbol
>>> r=Symbol("r", positive=True)
>>> phi=Symbol("phi", real=True)
>>> theta=Symbol("theta", real=True)
>>> Z=Symbol("Z", positive=True, integer=True, nonzero=True)
>>> Psi_nlm(1,0,0,r,phi,theta,Z)
Z**(3/2)*exp(-Z*r)/sqrt(pi)
>>> Psi_nlm(2,1,1,r,phi,theta,Z)
-Z**(5/2)*r*exp(I*phi)*exp(-Z*r/2)*sin(theta)/(8*sqrt(pi))
Integrating the absolute square of a hydrogen wavefunction psi_{nlm}
over the whole space leads 1.
The normalization of the hydrogen wavefunctions Psi_nlm is:
>>> from sympy import integrate, conjugate, pi, oo, sin
>>> wf=Psi_nlm(2,1,1,r,phi,theta,Z)
>>> abs_sqrd=wf*conjugate(wf)
>>> jacobi=r**2*sin(theta)
>>> integrate(abs_sqrd*jacobi, (r,0,oo), (phi,0,2*pi), (theta,0,pi))
1
"""
# sympify arguments
n, l, m, r, phi, theta, Z = map(S, [n, l, m, r, phi, theta, Z])
# check if values for n,l,m make physically sense
if n.is_integer and n < 1:
raise ValueError("'n' must be positive integer")
if l.is_integer and not (n > l):
raise ValueError("'n' must be greater than 'l'")
if m.is_integer and not (abs(m) <= l):
raise ValueError("|'m'| must be less or equal 'l'")
# return the hydrogen wave function
return R_nl(n, l, r, Z)*Ynm(l, m, theta, phi).expand(func=True)
def E_nl(n, Z=1):
"""
Returns the energy of the state (n, l) in Hartree atomic units.
The energy does not depend on "l".
Parameters
==========
n : integer
Principal Quantum Number which is
an integer with possible values as 1, 2, 3, 4,...
Z :
Atomic number (1 for Hydrogen, 2 for Helium, ...)
Examples
========
>>> from sympy.physics.hydrogen import E_nl
>>> from sympy.abc import n, Z
>>> E_nl(n, Z)
-Z**2/(2*n**2)
>>> E_nl(1)
-1/2
>>> E_nl(2)
-1/8
>>> E_nl(3)
-1/18
>>> E_nl(3, 47)
-2209/18
"""
n, Z = S(n), S(Z)
if n.is_integer and (n < 1):
raise ValueError("'n' must be positive integer")
return -Z**2/(2*n**2)
def E_nl_dirac(n, l, spin_up=True, Z=1, c=Float("137.035999037")):
"""
Returns the relativistic energy of the state (n, l, spin) in Hartree atomic
units.
The energy is calculated from the Dirac equation. The rest mass energy is
*not* included.
Parameters
==========
n : integer
Principal Quantum Number which is
an integer with possible values as 1, 2, 3, 4,...
l : integer
``l`` is the Angular Momentum Quantum Number with
values ranging from 0 to ``n-1``.
spin_up :
True if the electron spin is up (default), otherwise down
Z :
Atomic number (1 for Hydrogen, 2 for Helium, ...)
c :
Speed of light in atomic units. Default value is 137.035999037,
taken from https://arxiv.org/abs/1012.3627
Examples
========
>>> from sympy.physics.hydrogen import E_nl_dirac
>>> E_nl_dirac(1, 0)
-0.500006656595360
>>> E_nl_dirac(2, 0)
-0.125002080189006
>>> E_nl_dirac(2, 1)
-0.125000416028342
>>> E_nl_dirac(2, 1, False)
-0.125002080189006
>>> E_nl_dirac(3, 0)
-0.0555562951740285
>>> E_nl_dirac(3, 1)
-0.0555558020932949
>>> E_nl_dirac(3, 1, False)
-0.0555562951740285
>>> E_nl_dirac(3, 2)
-0.0555556377366884
>>> E_nl_dirac(3, 2, False)
-0.0555558020932949
"""
n, l, Z, c = map(S, [n, l, Z, c])
if not (l >= 0):
raise ValueError("'l' must be positive or zero")
if not (n > l):
raise ValueError("'n' must be greater than 'l'")
if (l == 0 and spin_up is False):
raise ValueError("Spin must be up for l==0.")
# skappa is sign*kappa, where sign contains the correct sign
if spin_up:
skappa = -l - 1
else:
skappa = -l
beta = sqrt(skappa**2 - Z**2/c**2)
return c**2/sqrt(1 + Z**2/(n + skappa + beta)**2/c**2) - c**2
PK ]ZZZ|2�� � sympy/physics/matrices.py"""Known matrices related to physics"""
from sympy.core.numbers import I
from sympy.matrices.dense import MutableDenseMatrix as Matrix
from sympy.utilities.decorator import deprecated
def msigma(i):
r"""Returns a Pauli matrix `\sigma_i` with `i=1,2,3`.
References
==========
.. [1] https://en.wikipedia.org/wiki/Pauli_matrices
Examples
========
>>> from sympy.physics.matrices import msigma
>>> msigma(1)
Matrix([
[0, 1],
[1, 0]])
"""
if i == 1:
mat = (
(0, 1),
(1, 0)
)
elif i == 2:
mat = (
(0, -I),
(I, 0)
)
elif i == 3:
mat = (
(1, 0),
(0, -1)
)
else:
raise IndexError("Invalid Pauli index")
return Matrix(mat)
def pat_matrix(m, dx, dy, dz):
"""Returns the Parallel Axis Theorem matrix to translate the inertia
matrix a distance of `(dx, dy, dz)` for a body of mass m.
Examples
========
To translate a body having a mass of 2 units a distance of 1 unit along
the `x`-axis we get:
>>> from sympy.physics.matrices import pat_matrix
>>> pat_matrix(2, 1, 0, 0)
Matrix([
[0, 0, 0],
[0, 2, 0],
[0, 0, 2]])
"""
dxdy = -dx*dy
dydz = -dy*dz
dzdx = -dz*dx
dxdx = dx**2
dydy = dy**2
dzdz = dz**2
mat = ((dydy + dzdz, dxdy, dzdx),
(dxdy, dxdx + dzdz, dydz),
(dzdx, dydz, dydy + dxdx))
return m*Matrix(mat)
def mgamma(mu, lower=False):
r"""Returns a Dirac gamma matrix `\gamma^\mu` in the standard
(Dirac) representation.
Explanation
===========
If you want `\gamma_\mu`, use ``gamma(mu, True)``.
We use a convention:
`\gamma^5 = i \cdot \gamma^0 \cdot \gamma^1 \cdot \gamma^2 \cdot \gamma^3`
`\gamma_5 = i \cdot \gamma_0 \cdot \gamma_1 \cdot \gamma_2 \cdot \gamma_3 = - \gamma^5`
References
==========
.. [1] https://en.wikipedia.org/wiki/Gamma_matrices
Examples
========
>>> from sympy.physics.matrices import mgamma
>>> mgamma(1)
Matrix([
[ 0, 0, 0, 1],
[ 0, 0, 1, 0],
[ 0, -1, 0, 0],
[-1, 0, 0, 0]])
"""
if mu not in (0, 1, 2, 3, 5):
raise IndexError("Invalid Dirac index")
if mu == 0:
mat = (
(1, 0, 0, 0),
(0, 1, 0, 0),
(0, 0, -1, 0),
(0, 0, 0, -1)
)
elif mu == 1:
mat = (
(0, 0, 0, 1),
(0, 0, 1, 0),
(0, -1, 0, 0),
(-1, 0, 0, 0)
)
elif mu == 2:
mat = (
(0, 0, 0, -I),
(0, 0, I, 0),
(0, I, 0, 0),
(-I, 0, 0, 0)
)
elif mu == 3:
mat = (
(0, 0, 1, 0),
(0, 0, 0, -1),
(-1, 0, 0, 0),
(0, 1, 0, 0)
)
elif mu == 5:
mat = (
(0, 0, 1, 0),
(0, 0, 0, 1),
(1, 0, 0, 0),
(0, 1, 0, 0)
)
m = Matrix(mat)
if lower:
if mu in (1, 2, 3, 5):
m = -m
return m
#Minkowski tensor using the convention (+,-,-,-) used in the Quantum Field
#Theory
minkowski_tensor = Matrix( (
(1, 0, 0, 0),
(0, -1, 0, 0),
(0, 0, -1, 0),
(0, 0, 0, -1)
))
@deprecated(
"""
The sympy.physics.matrices.mdft method is deprecated. Use
sympy.DFT(n).as_explicit() instead.
""",
deprecated_since_version="1.9",
active_deprecations_target="deprecated-physics-mdft",
)
def mdft(n):
r"""
.. deprecated:: 1.9
Use DFT from sympy.matrices.expressions.fourier instead.
To get identical behavior to ``mdft(n)``, use ``DFT(n).as_explicit()``.
"""
from sympy.matrices.expressions.fourier import DFT
return DFT(n).as_mutable()
PK ]ZZZ=N �r r sympy/physics/paulialgebra.py"""
This module implements Pauli algebra by subclassing Symbol. Only algebraic
properties of Pauli matrices are used (we do not use the Matrix class).
See the documentation to the class Pauli for examples.
References
==========
.. [1] https://en.wikipedia.org/wiki/Pauli_matrices
"""
from sympy.core.add import Add
from sympy.core.mul import Mul
from sympy.core.numbers import I
from sympy.core.power import Pow
from sympy.core.symbol import Symbol
from sympy.physics.quantum import TensorProduct
__all__ = ['evaluate_pauli_product']
def delta(i, j):
"""
Returns 1 if ``i == j``, else 0.
This is used in the multiplication of Pauli matrices.
Examples
========
>>> from sympy.physics.paulialgebra import delta
>>> delta(1, 1)
1
>>> delta(2, 3)
0
"""
if i == j:
return 1
else:
return 0
def epsilon(i, j, k):
"""
Return 1 if i,j,k is equal to (1,2,3), (2,3,1), or (3,1,2);
-1 if ``i``,``j``,``k`` is equal to (1,3,2), (3,2,1), or (2,1,3);
else return 0.
This is used in the multiplication of Pauli matrices.
Examples
========
>>> from sympy.physics.paulialgebra import epsilon
>>> epsilon(1, 2, 3)
1
>>> epsilon(1, 3, 2)
-1
"""
if (i, j, k) in ((1, 2, 3), (2, 3, 1), (3, 1, 2)):
return 1
elif (i, j, k) in ((1, 3, 2), (3, 2, 1), (2, 1, 3)):
return -1
else:
return 0
class Pauli(Symbol):
"""
The class representing algebraic properties of Pauli matrices.
Explanation
===========
The symbol used to display the Pauli matrices can be changed with an
optional parameter ``label="sigma"``. Pauli matrices with different
``label`` attributes cannot multiply together.
If the left multiplication of symbol or number with Pauli matrix is needed,
please use parentheses to separate Pauli and symbolic multiplication
(for example: 2*I*(Pauli(3)*Pauli(2))).
Another variant is to use evaluate_pauli_product function to evaluate
the product of Pauli matrices and other symbols (with commutative
multiply rules).
See Also
========
evaluate_pauli_product
Examples
========
>>> from sympy.physics.paulialgebra import Pauli
>>> Pauli(1)
sigma1
>>> Pauli(1)*Pauli(2)
I*sigma3
>>> Pauli(1)*Pauli(1)
1
>>> Pauli(3)**4
1
>>> Pauli(1)*Pauli(2)*Pauli(3)
I
>>> from sympy.physics.paulialgebra import Pauli
>>> Pauli(1, label="tau")
tau1
>>> Pauli(1)*Pauli(2, label="tau")
sigma1*tau2
>>> Pauli(1, label="tau")*Pauli(2, label="tau")
I*tau3
>>> from sympy import I
>>> I*(Pauli(2)*Pauli(3))
-sigma1
>>> from sympy.physics.paulialgebra import evaluate_pauli_product
>>> f = I*Pauli(2)*Pauli(3)
>>> f
I*sigma2*sigma3
>>> evaluate_pauli_product(f)
-sigma1
"""
__slots__ = ("i", "label")
def __new__(cls, i, label="sigma"):
if i not in [1, 2, 3]:
raise IndexError("Invalid Pauli index")
obj = Symbol.__new__(cls, "%s%d" %(label,i), commutative=False, hermitian=True)
obj.i = i
obj.label = label
return obj
def __getnewargs_ex__(self):
return (self.i, self.label), {}
def _hashable_content(self):
return (self.i, self.label)
# FIXME don't work for -I*Pauli(2)*Pauli(3)
def __mul__(self, other):
if isinstance(other, Pauli):
j = self.i
k = other.i
jlab = self.label
klab = other.label
if jlab == klab:
return delta(j, k) \
+ I*epsilon(j, k, 1)*Pauli(1,jlab) \
+ I*epsilon(j, k, 2)*Pauli(2,jlab) \
+ I*epsilon(j, k, 3)*Pauli(3,jlab)
return super().__mul__(other)
def _eval_power(b, e):
if e.is_Integer and e.is_positive:
return super().__pow__(int(e) % 2)
def evaluate_pauli_product(arg):
'''Help function to evaluate Pauli matrices product
with symbolic objects.
Parameters
==========
arg: symbolic expression that contains Paulimatrices
Examples
========
>>> from sympy.physics.paulialgebra import Pauli, evaluate_pauli_product
>>> from sympy import I
>>> evaluate_pauli_product(I*Pauli(1)*Pauli(2))
-sigma3
>>> from sympy.abc import x
>>> evaluate_pauli_product(x**2*Pauli(2)*Pauli(1))
-I*x**2*sigma3
'''
start = arg
end = arg
if isinstance(arg, Pow) and isinstance(arg.args[0], Pauli):
if arg.args[1].is_odd:
return arg.args[0]
else:
return 1
if isinstance(arg, Add):
return Add(*[evaluate_pauli_product(part) for part in arg.args])
if isinstance(arg, TensorProduct):
return TensorProduct(*[evaluate_pauli_product(part) for part in arg.args])
elif not(isinstance(arg, Mul)):
return arg
while not start == end or start == arg and end == arg:
start = end
tmp = start.as_coeff_mul()
sigma_product = 1
com_product = 1
keeper = 1
for el in tmp[1]:
if isinstance(el, Pauli):
sigma_product *= el
elif not el.is_commutative:
if isinstance(el, Pow) and isinstance(el.args[0], Pauli):
if el.args[1].is_odd:
sigma_product *= el.args[0]
elif isinstance(el, TensorProduct):
keeper = keeper*sigma_product*\
TensorProduct(
*[evaluate_pauli_product(part) for part in el.args]
)
sigma_product = 1
else:
keeper = keeper*sigma_product*el
sigma_product = 1
else:
com_product *= el
end = tmp[0]*keeper*sigma_product*com_product
if end == arg: break
return end
PK ]ZZZ���� � sympy/physics/pring.pyfrom sympy.core.numbers import (I, pi)
from sympy.core.singleton import S
from sympy.functions.elementary.exponential import exp
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.physics.quantum.constants import hbar
def wavefunction(n, x):
"""
Returns the wavefunction for particle on ring.
Parameters
==========
n : The quantum number.
Here ``n`` can be positive as well as negative
which can be used to describe the direction of motion of particle.
x :
The angle.
Examples
========
>>> from sympy.physics.pring import wavefunction
>>> from sympy import Symbol, integrate, pi
>>> x=Symbol("x")
>>> wavefunction(1, x)
sqrt(2)*exp(I*x)/(2*sqrt(pi))
>>> wavefunction(2, x)
sqrt(2)*exp(2*I*x)/(2*sqrt(pi))
>>> wavefunction(3, x)
sqrt(2)*exp(3*I*x)/(2*sqrt(pi))
The normalization of the wavefunction is:
>>> integrate(wavefunction(2, x)*wavefunction(-2, x), (x, 0, 2*pi))
1
>>> integrate(wavefunction(4, x)*wavefunction(-4, x), (x, 0, 2*pi))
1
References
==========
.. [1] Atkins, Peter W.; Friedman, Ronald (2005). Molecular Quantum
Mechanics (4th ed.). Pages 71-73.
"""
# sympify arguments
n, x = S(n), S(x)
return exp(n * I * x) / sqrt(2 * pi)
def energy(n, m, r):
"""
Returns the energy of the state corresponding to quantum number ``n``.
E=(n**2 * (hcross)**2) / (2 * m * r**2)
Parameters
==========
n :
The quantum number.
m :
Mass of the particle.
r :
Radius of circle.
Examples
========
>>> from sympy.physics.pring import energy
>>> from sympy import Symbol
>>> m=Symbol("m")
>>> r=Symbol("r")
>>> energy(1, m, r)
hbar**2/(2*m*r**2)
>>> energy(2, m, r)
2*hbar**2/(m*r**2)
>>> energy(-2, 2.0, 3.0)
0.111111111111111*hbar**2
References
==========
.. [1] Atkins, Peter W.; Friedman, Ronald (2005). Molecular Quantum
Mechanics (4th ed.). Pages 71-73.
"""
n, m, r = S(n), S(m), S(r)
if n.is_integer:
return (n**2 * hbar**2) / (2 * m * r**2)
else:
raise ValueError("'n' must be integer")
PK ]ZZZ�_�� � sympy/physics/qho_1d.pyfrom sympy.core import S, pi, Rational
from sympy.functions import hermite, sqrt, exp, factorial, Abs
from sympy.physics.quantum.constants import hbar
def psi_n(n, x, m, omega):
"""
Returns the wavefunction psi_{n} for the One-dimensional harmonic oscillator.
Parameters
==========
n :
the "nodal" quantum number. Corresponds to the number of nodes in the
wavefunction. ``n >= 0``
x :
x coordinate.
m :
Mass of the particle.
omega :
Angular frequency of the oscillator.
Examples
========
>>> from sympy.physics.qho_1d import psi_n
>>> from sympy.abc import m, x, omega
>>> psi_n(0, x, m, omega)
(m*omega)**(1/4)*exp(-m*omega*x**2/(2*hbar))/(hbar**(1/4)*pi**(1/4))
"""
# sympify arguments
n, x, m, omega = map(S, [n, x, m, omega])
nu = m * omega / hbar
# normalization coefficient
C = (nu/pi)**Rational(1, 4) * sqrt(1/(2**n*factorial(n)))
return C * exp(-nu* x**2 /2) * hermite(n, sqrt(nu)*x)
def E_n(n, omega):
"""
Returns the Energy of the One-dimensional harmonic oscillator.
Parameters
==========
n :
The "nodal" quantum number.
omega :
The harmonic oscillator angular frequency.
Notes
=====
The unit of the returned value matches the unit of hw, since the energy is
calculated as:
E_n = hbar * omega*(n + 1/2)
Examples
========
>>> from sympy.physics.qho_1d import E_n
>>> from sympy.abc import x, omega
>>> E_n(x, omega)
hbar*omega*(x + 1/2)
"""
return hbar * omega * (n + S.Half)
def coherent_state(n, alpha):
"""
Returns <n|alpha> for the coherent states of 1D harmonic oscillator.
See https://en.wikipedia.org/wiki/Coherent_states
Parameters
==========
n :
The "nodal" quantum number.
alpha :
The eigen value of annihilation operator.
"""
return exp(- Abs(alpha)**2/2)*(alpha**n)/sqrt(factorial(n))
PK ]ZZZ�8�# a a sympy/physics/secondquant.py"""
Second quantization operators and states for bosons.
This follow the formulation of Fetter and Welecka, "Quantum Theory
of Many-Particle Systems."
"""
from collections import defaultdict
from sympy.core.add import Add
from sympy.core.basic import Basic
from sympy.core.cache import cacheit
from sympy.core.containers import Tuple
from sympy.core.expr import Expr
from sympy.core.function import Function
from sympy.core.mul import Mul
from sympy.core.numbers import I
from sympy.core.power import Pow
from sympy.core.singleton import S
from sympy.core.sorting import default_sort_key
from sympy.core.symbol import Dummy, Symbol
from sympy.core.sympify import sympify
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.special.tensor_functions import KroneckerDelta
from sympy.matrices.dense import zeros
from sympy.printing.str import StrPrinter
from sympy.utilities.iterables import has_dups
__all__ = [
'Dagger',
'KroneckerDelta',
'BosonicOperator',
'AnnihilateBoson',
'CreateBoson',
'AnnihilateFermion',
'CreateFermion',
'FockState',
'FockStateBra',
'FockStateKet',
'FockStateBosonKet',
'FockStateBosonBra',
'FockStateFermionKet',
'FockStateFermionBra',
'BBra',
'BKet',
'FBra',
'FKet',
'F',
'Fd',
'B',
'Bd',
'apply_operators',
'InnerProduct',
'BosonicBasis',
'VarBosonicBasis',
'FixedBosonicBasis',
'Commutator',
'matrix_rep',
'contraction',
'wicks',
'NO',
'evaluate_deltas',
'AntiSymmetricTensor',
'substitute_dummies',
'PermutationOperator',
'simplify_index_permutations',
]
class SecondQuantizationError(Exception):
pass
class AppliesOnlyToSymbolicIndex(SecondQuantizationError):
pass
class ContractionAppliesOnlyToFermions(SecondQuantizationError):
pass
class ViolationOfPauliPrinciple(SecondQuantizationError):
pass
class SubstitutionOfAmbigousOperatorFailed(SecondQuantizationError):
pass
class WicksTheoremDoesNotApply(SecondQuantizationError):
pass
class Dagger(Expr):
"""
Hermitian conjugate of creation/annihilation operators.
Examples
========
>>> from sympy import I
>>> from sympy.physics.secondquant import Dagger, B, Bd
>>> Dagger(2*I)
-2*I
>>> Dagger(B(0))
CreateBoson(0)
>>> Dagger(Bd(0))
AnnihilateBoson(0)
"""
def __new__(cls, arg):
arg = sympify(arg)
r = cls.eval(arg)
if isinstance(r, Basic):
return r
obj = Basic.__new__(cls, arg)
return obj
@classmethod
def eval(cls, arg):
"""
Evaluates the Dagger instance.
Examples
========
>>> from sympy import I
>>> from sympy.physics.secondquant import Dagger, B, Bd
>>> Dagger(2*I)
-2*I
>>> Dagger(B(0))
CreateBoson(0)
>>> Dagger(Bd(0))
AnnihilateBoson(0)
The eval() method is called automatically.
"""
dagger = getattr(arg, '_dagger_', None)
if dagger is not None:
return dagger()
if isinstance(arg, Basic):
if arg.is_Add:
return Add(*tuple(map(Dagger, arg.args)))
if arg.is_Mul:
return Mul(*tuple(map(Dagger, reversed(arg.args))))
if arg.is_Number:
return arg
if arg.is_Pow:
return Pow(Dagger(arg.args[0]), arg.args[1])
if arg == I:
return -arg
else:
return None
def _dagger_(self):
return self.args[0]
class TensorSymbol(Expr):
is_commutative = True
class AntiSymmetricTensor(TensorSymbol):
"""Stores upper and lower indices in separate Tuple's.
Each group of indices is assumed to be antisymmetric.
Examples
========
>>> from sympy import symbols
>>> from sympy.physics.secondquant import AntiSymmetricTensor
>>> i, j = symbols('i j', below_fermi=True)
>>> a, b = symbols('a b', above_fermi=True)
>>> AntiSymmetricTensor('v', (a, i), (b, j))
AntiSymmetricTensor(v, (a, i), (b, j))
>>> AntiSymmetricTensor('v', (i, a), (b, j))
-AntiSymmetricTensor(v, (a, i), (b, j))
As you can see, the indices are automatically sorted to a canonical form.
"""
def __new__(cls, symbol, upper, lower):
try:
upper, signu = _sort_anticommuting_fermions(
upper, key=cls._sortkey)
lower, signl = _sort_anticommuting_fermions(
lower, key=cls._sortkey)
except ViolationOfPauliPrinciple:
return S.Zero
symbol = sympify(symbol)
upper = Tuple(*upper)
lower = Tuple(*lower)
if (signu + signl) % 2:
return -TensorSymbol.__new__(cls, symbol, upper, lower)
else:
return TensorSymbol.__new__(cls, symbol, upper, lower)
@classmethod
def _sortkey(cls, index):
"""Key for sorting of indices.
particle < hole < general
FIXME: This is a bottle-neck, can we do it faster?
"""
h = hash(index)
label = str(index)
if isinstance(index, Dummy):
if index.assumptions0.get('above_fermi'):
return (20, label, h)
elif index.assumptions0.get('below_fermi'):
return (21, label, h)
else:
return (22, label, h)
if index.assumptions0.get('above_fermi'):
return (10, label, h)
elif index.assumptions0.get('below_fermi'):
return (11, label, h)
else:
return (12, label, h)
def _latex(self, printer):
return "{%s^{%s}_{%s}}" % (
self.symbol,
"".join([ i.name for i in self.args[1]]),
"".join([ i.name for i in self.args[2]])
)
@property
def symbol(self):
"""
Returns the symbol of the tensor.
Examples
========
>>> from sympy import symbols
>>> from sympy.physics.secondquant import AntiSymmetricTensor
>>> i, j = symbols('i,j', below_fermi=True)
>>> a, b = symbols('a,b', above_fermi=True)
>>> AntiSymmetricTensor('v', (a, i), (b, j))
AntiSymmetricTensor(v, (a, i), (b, j))
>>> AntiSymmetricTensor('v', (a, i), (b, j)).symbol
v
"""
return self.args[0]
@property
def upper(self):
"""
Returns the upper indices.
Examples
========
>>> from sympy import symbols
>>> from sympy.physics.secondquant import AntiSymmetricTensor
>>> i, j = symbols('i,j', below_fermi=True)
>>> a, b = symbols('a,b', above_fermi=True)
>>> AntiSymmetricTensor('v', (a, i), (b, j))
AntiSymmetricTensor(v, (a, i), (b, j))
>>> AntiSymmetricTensor('v', (a, i), (b, j)).upper
(a, i)
"""
return self.args[1]
@property
def lower(self):
"""
Returns the lower indices.
Examples
========
>>> from sympy import symbols
>>> from sympy.physics.secondquant import AntiSymmetricTensor
>>> i, j = symbols('i,j', below_fermi=True)
>>> a, b = symbols('a,b', above_fermi=True)
>>> AntiSymmetricTensor('v', (a, i), (b, j))
AntiSymmetricTensor(v, (a, i), (b, j))
>>> AntiSymmetricTensor('v', (a, i), (b, j)).lower
(b, j)
"""
return self.args[2]
def __str__(self):
return "%s(%s,%s)" % self.args
class SqOperator(Expr):
"""
Base class for Second Quantization operators.
"""
op_symbol = 'sq'
is_commutative = False
def __new__(cls, k):
obj = Basic.__new__(cls, sympify(k))
return obj
@property
def state(self):
"""
Returns the state index related to this operator.
Examples
========
>>> from sympy import Symbol
>>> from sympy.physics.secondquant import F, Fd, B, Bd
>>> p = Symbol('p')
>>> F(p).state
p
>>> Fd(p).state
p
>>> B(p).state
p
>>> Bd(p).state
p
"""
return self.args[0]
@property
def is_symbolic(self):
"""
Returns True if the state is a symbol (as opposed to a number).
Examples
========
>>> from sympy import Symbol
>>> from sympy.physics.secondquant import F
>>> p = Symbol('p')
>>> F(p).is_symbolic
True
>>> F(1).is_symbolic
False
"""
if self.state.is_Integer:
return False
else:
return True
def __repr__(self):
return NotImplemented
def __str__(self):
return "%s(%r)" % (self.op_symbol, self.state)
def apply_operator(self, state):
"""
Applies an operator to itself.
"""
raise NotImplementedError('implement apply_operator in a subclass')
class BosonicOperator(SqOperator):
pass
class Annihilator(SqOperator):
pass
class Creator(SqOperator):
pass
class AnnihilateBoson(BosonicOperator, Annihilator):
"""
Bosonic annihilation operator.
Examples
========
>>> from sympy.physics.secondquant import B
>>> from sympy.abc import x
>>> B(x)
AnnihilateBoson(x)
"""
op_symbol = 'b'
def _dagger_(self):
return CreateBoson(self.state)
def apply_operator(self, state):
"""
Apply state to self if self is not symbolic and state is a FockStateKet, else
multiply self by state.
Examples
========
>>> from sympy.physics.secondquant import B, BKet
>>> from sympy.abc import x, y, n
>>> B(x).apply_operator(y)
y*AnnihilateBoson(x)
>>> B(0).apply_operator(BKet((n,)))
sqrt(n)*FockStateBosonKet((n - 1,))
"""
if not self.is_symbolic and isinstance(state, FockStateKet):
element = self.state
amp = sqrt(state[element])
return amp*state.down(element)
else:
return Mul(self, state)
def __repr__(self):
return "AnnihilateBoson(%s)" % self.state
def _latex(self, printer):
if self.state is S.Zero:
return "b_{0}"
else:
return "b_{%s}" % self.state.name
class CreateBoson(BosonicOperator, Creator):
"""
Bosonic creation operator.
"""
op_symbol = 'b+'
def _dagger_(self):
return AnnihilateBoson(self.state)
def apply_operator(self, state):
"""
Apply state to self if self is not symbolic and state is a FockStateKet, else
multiply self by state.
Examples
========
>>> from sympy.physics.secondquant import B, Dagger, BKet
>>> from sympy.abc import x, y, n
>>> Dagger(B(x)).apply_operator(y)
y*CreateBoson(x)
>>> B(0).apply_operator(BKet((n,)))
sqrt(n)*FockStateBosonKet((n - 1,))
"""
if not self.is_symbolic and isinstance(state, FockStateKet):
element = self.state
amp = sqrt(state[element] + 1)
return amp*state.up(element)
else:
return Mul(self, state)
def __repr__(self):
return "CreateBoson(%s)" % self.state
def _latex(self, printer):
if self.state is S.Zero:
return "{b^\\dagger_{0}}"
else:
return "{b^\\dagger_{%s}}" % self.state.name
B = AnnihilateBoson
Bd = CreateBoson
class FermionicOperator(SqOperator):
@property
def is_restricted(self):
"""
Is this FermionicOperator restricted with respect to fermi level?
Returns
=======
1 : restricted to orbits above fermi
0 : no restriction
-1 : restricted to orbits below fermi
Examples
========
>>> from sympy import Symbol
>>> from sympy.physics.secondquant import F, Fd
>>> a = Symbol('a', above_fermi=True)
>>> i = Symbol('i', below_fermi=True)
>>> p = Symbol('p')
>>> F(a).is_restricted
1
>>> Fd(a).is_restricted
1
>>> F(i).is_restricted
-1
>>> Fd(i).is_restricted
-1
>>> F(p).is_restricted
0
>>> Fd(p).is_restricted
0
"""
ass = self.args[0].assumptions0
if ass.get("below_fermi"):
return -1
if ass.get("above_fermi"):
return 1
return 0
@property
def is_above_fermi(self):
"""
Does the index of this FermionicOperator allow values above fermi?
Examples
========
>>> from sympy import Symbol
>>> from sympy.physics.secondquant import F
>>> a = Symbol('a', above_fermi=True)
>>> i = Symbol('i', below_fermi=True)
>>> p = Symbol('p')
>>> F(a).is_above_fermi
True
>>> F(i).is_above_fermi
False
>>> F(p).is_above_fermi
True
Note
====
The same applies to creation operators Fd
"""
return not self.args[0].assumptions0.get("below_fermi")
@property
def is_below_fermi(self):
"""
Does the index of this FermionicOperator allow values below fermi?
Examples
========
>>> from sympy import Symbol
>>> from sympy.physics.secondquant import F
>>> a = Symbol('a', above_fermi=True)
>>> i = Symbol('i', below_fermi=True)
>>> p = Symbol('p')
>>> F(a).is_below_fermi
False
>>> F(i).is_below_fermi
True
>>> F(p).is_below_fermi
True
The same applies to creation operators Fd
"""
return not self.args[0].assumptions0.get("above_fermi")
@property
def is_only_below_fermi(self):
"""
Is the index of this FermionicOperator restricted to values below fermi?
Examples
========
>>> from sympy import Symbol
>>> from sympy.physics.secondquant import F
>>> a = Symbol('a', above_fermi=True)
>>> i = Symbol('i', below_fermi=True)
>>> p = Symbol('p')
>>> F(a).is_only_below_fermi
False
>>> F(i).is_only_below_fermi
True
>>> F(p).is_only_below_fermi
False
The same applies to creation operators Fd
"""
return self.is_below_fermi and not self.is_above_fermi
@property
def is_only_above_fermi(self):
"""
Is the index of this FermionicOperator restricted to values above fermi?
Examples
========
>>> from sympy import Symbol
>>> from sympy.physics.secondquant import F
>>> a = Symbol('a', above_fermi=True)
>>> i = Symbol('i', below_fermi=True)
>>> p = Symbol('p')
>>> F(a).is_only_above_fermi
True
>>> F(i).is_only_above_fermi
False
>>> F(p).is_only_above_fermi
False
The same applies to creation operators Fd
"""
return self.is_above_fermi and not self.is_below_fermi
def _sortkey(self):
h = hash(self)
label = str(self.args[0])
if self.is_only_q_creator:
return 1, label, h
if self.is_only_q_annihilator:
return 4, label, h
if isinstance(self, Annihilator):
return 3, label, h
if isinstance(self, Creator):
return 2, label, h
class AnnihilateFermion(FermionicOperator, Annihilator):
"""
Fermionic annihilation operator.
"""
op_symbol = 'f'
def _dagger_(self):
return CreateFermion(self.state)
def apply_operator(self, state):
"""
Apply state to self if self is not symbolic and state is a FockStateKet, else
multiply self by state.
Examples
========
>>> from sympy.physics.secondquant import B, Dagger, BKet
>>> from sympy.abc import x, y, n
>>> Dagger(B(x)).apply_operator(y)
y*CreateBoson(x)
>>> B(0).apply_operator(BKet((n,)))
sqrt(n)*FockStateBosonKet((n - 1,))
"""
if isinstance(state, FockStateFermionKet):
element = self.state
return state.down(element)
elif isinstance(state, Mul):
c_part, nc_part = state.args_cnc()
if isinstance(nc_part[0], FockStateFermionKet):
element = self.state
return Mul(*(c_part + [nc_part[0].down(element)] + nc_part[1:]))
else:
return Mul(self, state)
else:
return Mul(self, state)
@property
def is_q_creator(self):
"""
Can we create a quasi-particle? (create hole or create particle)
If so, would that be above or below the fermi surface?
Examples
========
>>> from sympy import Symbol
>>> from sympy.physics.secondquant import F
>>> a = Symbol('a', above_fermi=True)
>>> i = Symbol('i', below_fermi=True)
>>> p = Symbol('p')
>>> F(a).is_q_creator
0
>>> F(i).is_q_creator
-1
>>> F(p).is_q_creator
-1
"""
if self.is_below_fermi:
return -1
return 0
@property
def is_q_annihilator(self):
"""
Can we destroy a quasi-particle? (annihilate hole or annihilate particle)
If so, would that be above or below the fermi surface?
Examples
========
>>> from sympy import Symbol
>>> from sympy.physics.secondquant import F
>>> a = Symbol('a', above_fermi=1)
>>> i = Symbol('i', below_fermi=1)
>>> p = Symbol('p')
>>> F(a).is_q_annihilator
1
>>> F(i).is_q_annihilator
0
>>> F(p).is_q_annihilator
1
"""
if self.is_above_fermi:
return 1
return 0
@property
def is_only_q_creator(self):
"""
Always create a quasi-particle? (create hole or create particle)
Examples
========
>>> from sympy import Symbol
>>> from sympy.physics.secondquant import F
>>> a = Symbol('a', above_fermi=True)
>>> i = Symbol('i', below_fermi=True)
>>> p = Symbol('p')
>>> F(a).is_only_q_creator
False
>>> F(i).is_only_q_creator
True
>>> F(p).is_only_q_creator
False
"""
return self.is_only_below_fermi
@property
def is_only_q_annihilator(self):
"""
Always destroy a quasi-particle? (annihilate hole or annihilate particle)
Examples
========
>>> from sympy import Symbol
>>> from sympy.physics.secondquant import F
>>> a = Symbol('a', above_fermi=True)
>>> i = Symbol('i', below_fermi=True)
>>> p = Symbol('p')
>>> F(a).is_only_q_annihilator
True
>>> F(i).is_only_q_annihilator
False
>>> F(p).is_only_q_annihilator
False
"""
return self.is_only_above_fermi
def __repr__(self):
return "AnnihilateFermion(%s)" % self.state
def _latex(self, printer):
if self.state is S.Zero:
return "a_{0}"
else:
return "a_{%s}" % self.state.name
class CreateFermion(FermionicOperator, Creator):
"""
Fermionic creation operator.
"""
op_symbol = 'f+'
def _dagger_(self):
return AnnihilateFermion(self.state)
def apply_operator(self, state):
"""
Apply state to self if self is not symbolic and state is a FockStateKet, else
multiply self by state.
Examples
========
>>> from sympy.physics.secondquant import B, Dagger, BKet
>>> from sympy.abc import x, y, n
>>> Dagger(B(x)).apply_operator(y)
y*CreateBoson(x)
>>> B(0).apply_operator(BKet((n,)))
sqrt(n)*FockStateBosonKet((n - 1,))
"""
if isinstance(state, FockStateFermionKet):
element = self.state
return state.up(element)
elif isinstance(state, Mul):
c_part, nc_part = state.args_cnc()
if isinstance(nc_part[0], FockStateFermionKet):
element = self.state
return Mul(*(c_part + [nc_part[0].up(element)] + nc_part[1:]))
return Mul(self, state)
@property
def is_q_creator(self):
"""
Can we create a quasi-particle? (create hole or create particle)
If so, would that be above or below the fermi surface?
Examples
========
>>> from sympy import Symbol
>>> from sympy.physics.secondquant import Fd
>>> a = Symbol('a', above_fermi=True)
>>> i = Symbol('i', below_fermi=True)
>>> p = Symbol('p')
>>> Fd(a).is_q_creator
1
>>> Fd(i).is_q_creator
0
>>> Fd(p).is_q_creator
1
"""
if self.is_above_fermi:
return 1
return 0
@property
def is_q_annihilator(self):
"""
Can we destroy a quasi-particle? (annihilate hole or annihilate particle)
If so, would that be above or below the fermi surface?
Examples
========
>>> from sympy import Symbol
>>> from sympy.physics.secondquant import Fd
>>> a = Symbol('a', above_fermi=1)
>>> i = Symbol('i', below_fermi=1)
>>> p = Symbol('p')
>>> Fd(a).is_q_annihilator
0
>>> Fd(i).is_q_annihilator
-1
>>> Fd(p).is_q_annihilator
-1
"""
if self.is_below_fermi:
return -1
return 0
@property
def is_only_q_creator(self):
"""
Always create a quasi-particle? (create hole or create particle)
Examples
========
>>> from sympy import Symbol
>>> from sympy.physics.secondquant import Fd
>>> a = Symbol('a', above_fermi=True)
>>> i = Symbol('i', below_fermi=True)
>>> p = Symbol('p')
>>> Fd(a).is_only_q_creator
True
>>> Fd(i).is_only_q_creator
False
>>> Fd(p).is_only_q_creator
False
"""
return self.is_only_above_fermi
@property
def is_only_q_annihilator(self):
"""
Always destroy a quasi-particle? (annihilate hole or annihilate particle)
Examples
========
>>> from sympy import Symbol
>>> from sympy.physics.secondquant import Fd
>>> a = Symbol('a', above_fermi=True)
>>> i = Symbol('i', below_fermi=True)
>>> p = Symbol('p')
>>> Fd(a).is_only_q_annihilator
False
>>> Fd(i).is_only_q_annihilator
True
>>> Fd(p).is_only_q_annihilator
False
"""
return self.is_only_below_fermi
def __repr__(self):
return "CreateFermion(%s)" % self.state
def _latex(self, printer):
if self.state is S.Zero:
return "{a^\\dagger_{0}}"
else:
return "{a^\\dagger_{%s}}" % self.state.name
Fd = CreateFermion
F = AnnihilateFermion
class FockState(Expr):
"""
Many particle Fock state with a sequence of occupation numbers.
Anywhere you can have a FockState, you can also have S.Zero.
All code must check for this!
Base class to represent FockStates.
"""
is_commutative = False
def __new__(cls, occupations):
"""
occupations is a list with two possible meanings:
- For bosons it is a list of occupation numbers.
Element i is the number of particles in state i.
- For fermions it is a list of occupied orbits.
Element 0 is the state that was occupied first, element i
is the i'th occupied state.
"""
occupations = list(map(sympify, occupations))
obj = Basic.__new__(cls, Tuple(*occupations))
return obj
def __getitem__(self, i):
i = int(i)
return self.args[0][i]
def __repr__(self):
return ("FockState(%r)") % (self.args)
def __str__(self):
return "%s%r%s" % (getattr(self, 'lbracket', ""), self._labels(), getattr(self, 'rbracket', ""))
def _labels(self):
return self.args[0]
def __len__(self):
return len(self.args[0])
def _latex(self, printer):
return "%s%s%s" % (getattr(self, 'lbracket_latex', ""), printer._print(self._labels()), getattr(self, 'rbracket_latex', ""))
class BosonState(FockState):
"""
Base class for FockStateBoson(Ket/Bra).
"""
def up(self, i):
"""
Performs the action of a creation operator.
Examples
========
>>> from sympy.physics.secondquant import BBra
>>> b = BBra([1, 2])
>>> b
FockStateBosonBra((1, 2))
>>> b.up(1)
FockStateBosonBra((1, 3))
"""
i = int(i)
new_occs = list(self.args[0])
new_occs[i] = new_occs[i] + S.One
return self.__class__(new_occs)
def down(self, i):
"""
Performs the action of an annihilation operator.
Examples
========
>>> from sympy.physics.secondquant import BBra
>>> b = BBra([1, 2])
>>> b
FockStateBosonBra((1, 2))
>>> b.down(1)
FockStateBosonBra((1, 1))
"""
i = int(i)
new_occs = list(self.args[0])
if new_occs[i] == S.Zero:
return S.Zero
else:
new_occs[i] = new_occs[i] - S.One
return self.__class__(new_occs)
class FermionState(FockState):
"""
Base class for FockStateFermion(Ket/Bra).
"""
fermi_level = 0
def __new__(cls, occupations, fermi_level=0):
occupations = list(map(sympify, occupations))
if len(occupations) > 1:
try:
(occupations, sign) = _sort_anticommuting_fermions(
occupations, key=hash)
except ViolationOfPauliPrinciple:
return S.Zero
else:
sign = 0
cls.fermi_level = fermi_level
if cls._count_holes(occupations) > fermi_level:
return S.Zero
if sign % 2:
return S.NegativeOne*FockState.__new__(cls, occupations)
else:
return FockState.__new__(cls, occupations)
def up(self, i):
"""
Performs the action of a creation operator.
Explanation
===========
If below fermi we try to remove a hole,
if above fermi we try to create a particle.
If general index p we return ``Kronecker(p,i)*self``
where ``i`` is a new symbol with restriction above or below.
Examples
========
>>> from sympy import Symbol
>>> from sympy.physics.secondquant import FKet
>>> a = Symbol('a', above_fermi=True)
>>> i = Symbol('i', below_fermi=True)
>>> p = Symbol('p')
>>> FKet([]).up(a)
FockStateFermionKet((a,))
A creator acting on vacuum below fermi vanishes
>>> FKet([]).up(i)
0
"""
present = i in self.args[0]
if self._only_above_fermi(i):
if present:
return S.Zero
else:
return self._add_orbit(i)
elif self._only_below_fermi(i):
if present:
return self._remove_orbit(i)
else:
return S.Zero
else:
if present:
hole = Dummy("i", below_fermi=True)
return KroneckerDelta(i, hole)*self._remove_orbit(i)
else:
particle = Dummy("a", above_fermi=True)
return KroneckerDelta(i, particle)*self._add_orbit(i)
def down(self, i):
"""
Performs the action of an annihilation operator.
Explanation
===========
If below fermi we try to create a hole,
If above fermi we try to remove a particle.
If general index p we return ``Kronecker(p,i)*self``
where ``i`` is a new symbol with restriction above or below.
Examples
========
>>> from sympy import Symbol
>>> from sympy.physics.secondquant import FKet
>>> a = Symbol('a', above_fermi=True)
>>> i = Symbol('i', below_fermi=True)
>>> p = Symbol('p')
An annihilator acting on vacuum above fermi vanishes
>>> FKet([]).down(a)
0
Also below fermi, it vanishes, unless we specify a fermi level > 0
>>> FKet([]).down(i)
0
>>> FKet([],4).down(i)
FockStateFermionKet((i,))
"""
present = i in self.args[0]
if self._only_above_fermi(i):
if present:
return self._remove_orbit(i)
else:
return S.Zero
elif self._only_below_fermi(i):
if present:
return S.Zero
else:
return self._add_orbit(i)
else:
if present:
hole = Dummy("i", below_fermi=True)
return KroneckerDelta(i, hole)*self._add_orbit(i)
else:
particle = Dummy("a", above_fermi=True)
return KroneckerDelta(i, particle)*self._remove_orbit(i)
@classmethod
def _only_below_fermi(cls, i):
"""
Tests if given orbit is only below fermi surface.
If nothing can be concluded we return a conservative False.
"""
if i.is_number:
return i <= cls.fermi_level
if i.assumptions0.get('below_fermi'):
return True
return False
@classmethod
def _only_above_fermi(cls, i):
"""
Tests if given orbit is only above fermi surface.
If fermi level has not been set we return True.
If nothing can be concluded we return a conservative False.
"""
if i.is_number:
return i > cls.fermi_level
if i.assumptions0.get('above_fermi'):
return True
return not cls.fermi_level
def _remove_orbit(self, i):
"""
Removes particle/fills hole in orbit i. No input tests performed here.
"""
new_occs = list(self.args[0])
pos = new_occs.index(i)
del new_occs[pos]
if (pos) % 2:
return S.NegativeOne*self.__class__(new_occs, self.fermi_level)
else:
return self.__class__(new_occs, self.fermi_level)
def _add_orbit(self, i):
"""
Adds particle/creates hole in orbit i. No input tests performed here.
"""
return self.__class__((i,) + self.args[0], self.fermi_level)
@classmethod
def _count_holes(cls, list):
"""
Returns the number of identified hole states in list.
"""
return len([i for i in list if cls._only_below_fermi(i)])
def _negate_holes(self, list):
return tuple([-i if i <= self.fermi_level else i for i in list])
def __repr__(self):
if self.fermi_level:
return "FockStateKet(%r, fermi_level=%s)" % (self.args[0], self.fermi_level)
else:
return "FockStateKet(%r)" % (self.args[0],)
def _labels(self):
return self._negate_holes(self.args[0])
class FockStateKet(FockState):
"""
Representation of a ket.
"""
lbracket = '|'
rbracket = '>'
lbracket_latex = r'\left|'
rbracket_latex = r'\right\rangle'
class FockStateBra(FockState):
"""
Representation of a bra.
"""
lbracket = '<'
rbracket = '|'
lbracket_latex = r'\left\langle'
rbracket_latex = r'\right|'
def __mul__(self, other):
if isinstance(other, FockStateKet):
return InnerProduct(self, other)
else:
return Expr.__mul__(self, other)
class FockStateBosonKet(BosonState, FockStateKet):
"""
Many particle Fock state with a sequence of occupation numbers.
Occupation numbers can be any integer >= 0.
Examples
========
>>> from sympy.physics.secondquant import BKet
>>> BKet([1, 2])
FockStateBosonKet((1, 2))
"""
def _dagger_(self):
return FockStateBosonBra(*self.args)
class FockStateBosonBra(BosonState, FockStateBra):
"""
Describes a collection of BosonBra particles.
Examples
========
>>> from sympy.physics.secondquant import BBra
>>> BBra([1, 2])
FockStateBosonBra((1, 2))
"""
def _dagger_(self):
return FockStateBosonKet(*self.args)
class FockStateFermionKet(FermionState, FockStateKet):
"""
Many-particle Fock state with a sequence of occupied orbits.
Explanation
===========
Each state can only have one particle, so we choose to store a list of
occupied orbits rather than a tuple with occupation numbers (zeros and ones).
states below fermi level are holes, and are represented by negative labels
in the occupation list.
For symbolic state labels, the fermi_level caps the number of allowed hole-
states.
Examples
========
>>> from sympy.physics.secondquant import FKet
>>> FKet([1, 2])
FockStateFermionKet((1, 2))
"""
def _dagger_(self):
return FockStateFermionBra(*self.args)
class FockStateFermionBra(FermionState, FockStateBra):
"""
See Also
========
FockStateFermionKet
Examples
========
>>> from sympy.physics.secondquant import FBra
>>> FBra([1, 2])
FockStateFermionBra((1, 2))
"""
def _dagger_(self):
return FockStateFermionKet(*self.args)
BBra = FockStateBosonBra
BKet = FockStateBosonKet
FBra = FockStateFermionBra
FKet = FockStateFermionKet
def _apply_Mul(m):
"""
Take a Mul instance with operators and apply them to states.
Explanation
===========
This method applies all operators with integer state labels
to the actual states. For symbolic state labels, nothing is done.
When inner products of FockStates are encountered (like <a|b>),
they are converted to instances of InnerProduct.
This does not currently work on double inner products like,
<a|b><c|d>.
If the argument is not a Mul, it is simply returned as is.
"""
if not isinstance(m, Mul):
return m
c_part, nc_part = m.args_cnc()
n_nc = len(nc_part)
if n_nc in (0, 1):
return m
else:
last = nc_part[-1]
next_to_last = nc_part[-2]
if isinstance(last, FockStateKet):
if isinstance(next_to_last, SqOperator):
if next_to_last.is_symbolic:
return m
else:
result = next_to_last.apply_operator(last)
if result == 0:
return S.Zero
else:
return _apply_Mul(Mul(*(c_part + nc_part[:-2] + [result])))
elif isinstance(next_to_last, Pow):
if isinstance(next_to_last.base, SqOperator) and \
next_to_last.exp.is_Integer:
if next_to_last.base.is_symbolic:
return m
else:
result = last
for i in range(next_to_last.exp):
result = next_to_last.base.apply_operator(result)
if result == 0:
break
if result == 0:
return S.Zero
else:
return _apply_Mul(Mul(*(c_part + nc_part[:-2] + [result])))
else:
return m
elif isinstance(next_to_last, FockStateBra):
result = InnerProduct(next_to_last, last)
if result == 0:
return S.Zero
else:
return _apply_Mul(Mul(*(c_part + nc_part[:-2] + [result])))
else:
return m
else:
return m
def apply_operators(e):
"""
Take a SymPy expression with operators and states and apply the operators.
Examples
========
>>> from sympy.physics.secondquant import apply_operators
>>> from sympy import sympify
>>> apply_operators(sympify(3)+4)
7
"""
e = e.expand()
muls = e.atoms(Mul)
subs_list = [(m, _apply_Mul(m)) for m in iter(muls)]
return e.subs(subs_list)
class InnerProduct(Basic):
"""
An unevaluated inner product between a bra and ket.
Explanation
===========
Currently this class just reduces things to a product of
Kronecker Deltas. In the future, we could introduce abstract
states like ``|a>`` and ``|b>``, and leave the inner product unevaluated as
``<a|b>``.
"""
is_commutative = True
def __new__(cls, bra, ket):
if not isinstance(bra, FockStateBra):
raise TypeError("must be a bra")
if not isinstance(ket, FockStateKet):
raise TypeError("must be a ket")
return cls.eval(bra, ket)
@classmethod
def eval(cls, bra, ket):
result = S.One
for i, j in zip(bra.args[0], ket.args[0]):
result *= KroneckerDelta(i, j)
if result == 0:
break
return result
@property
def bra(self):
"""Returns the bra part of the state"""
return self.args[0]
@property
def ket(self):
"""Returns the ket part of the state"""
return self.args[1]
def __repr__(self):
sbra = repr(self.bra)
sket = repr(self.ket)
return "%s|%s" % (sbra[:-1], sket[1:])
def __str__(self):
return self.__repr__()
def matrix_rep(op, basis):
"""
Find the representation of an operator in a basis.
Examples
========
>>> from sympy.physics.secondquant import VarBosonicBasis, B, matrix_rep
>>> b = VarBosonicBasis(5)
>>> o = B(0)
>>> matrix_rep(o, b)
Matrix([
[0, 1, 0, 0, 0],
[0, 0, sqrt(2), 0, 0],
[0, 0, 0, sqrt(3), 0],
[0, 0, 0, 0, 2],
[0, 0, 0, 0, 0]])
"""
a = zeros(len(basis))
for i in range(len(basis)):
for j in range(len(basis)):
a[i, j] = apply_operators(Dagger(basis[i])*op*basis[j])
return a
class BosonicBasis:
"""
Base class for a basis set of bosonic Fock states.
"""
pass
class VarBosonicBasis:
"""
A single state, variable particle number basis set.
Examples
========
>>> from sympy.physics.secondquant import VarBosonicBasis
>>> b = VarBosonicBasis(5)
>>> b
[FockState((0,)), FockState((1,)), FockState((2,)),
FockState((3,)), FockState((4,))]
"""
def __init__(self, n_max):
self.n_max = n_max
self._build_states()
def _build_states(self):
self.basis = []
for i in range(self.n_max):
self.basis.append(FockStateBosonKet([i]))
self.n_basis = len(self.basis)
def index(self, state):
"""
Returns the index of state in basis.
Examples
========
>>> from sympy.physics.secondquant import VarBosonicBasis
>>> b = VarBosonicBasis(3)
>>> state = b.state(1)
>>> b
[FockState((0,)), FockState((1,)), FockState((2,))]
>>> state
FockStateBosonKet((1,))
>>> b.index(state)
1
"""
return self.basis.index(state)
def state(self, i):
"""
The state of a single basis.
Examples
========
>>> from sympy.physics.secondquant import VarBosonicBasis
>>> b = VarBosonicBasis(5)
>>> b.state(3)
FockStateBosonKet((3,))
"""
return self.basis[i]
def __getitem__(self, i):
return self.state(i)
def __len__(self):
return len(self.basis)
def __repr__(self):
return repr(self.basis)
class FixedBosonicBasis(BosonicBasis):
"""
Fixed particle number basis set.
Examples
========
>>> from sympy.physics.secondquant import FixedBosonicBasis
>>> b = FixedBosonicBasis(2, 2)
>>> state = b.state(1)
>>> b
[FockState((2, 0)), FockState((1, 1)), FockState((0, 2))]
>>> state
FockStateBosonKet((1, 1))
>>> b.index(state)
1
"""
def __init__(self, n_particles, n_levels):
self.n_particles = n_particles
self.n_levels = n_levels
self._build_particle_locations()
self._build_states()
def _build_particle_locations(self):
tup = ["i%i" % i for i in range(self.n_particles)]
first_loop = "for i0 in range(%i)" % self.n_levels
other_loops = ''
for cur, prev in zip(tup[1:], tup):
temp = "for %s in range(%s + 1) " % (cur, prev)
other_loops = other_loops + temp
tup_string = "(%s)" % ", ".join(tup)
list_comp = "[%s %s %s]" % (tup_string, first_loop, other_loops)
result = eval(list_comp)
if self.n_particles == 1:
result = [(item,) for item in result]
self.particle_locations = result
def _build_states(self):
self.basis = []
for tuple_of_indices in self.particle_locations:
occ_numbers = self.n_levels*[0]
for level in tuple_of_indices:
occ_numbers[level] += 1
self.basis.append(FockStateBosonKet(occ_numbers))
self.n_basis = len(self.basis)
def index(self, state):
"""Returns the index of state in basis.
Examples
========
>>> from sympy.physics.secondquant import FixedBosonicBasis
>>> b = FixedBosonicBasis(2, 3)
>>> b.index(b.state(3))
3
"""
return self.basis.index(state)
def state(self, i):
"""Returns the state that lies at index i of the basis
Examples
========
>>> from sympy.physics.secondquant import FixedBosonicBasis
>>> b = FixedBosonicBasis(2, 3)
>>> b.state(3)
FockStateBosonKet((1, 0, 1))
"""
return self.basis[i]
def __getitem__(self, i):
return self.state(i)
def __len__(self):
return len(self.basis)
def __repr__(self):
return repr(self.basis)
class Commutator(Function):
"""
The Commutator: [A, B] = A*B - B*A
The arguments are ordered according to .__cmp__()
Examples
========
>>> from sympy import symbols
>>> from sympy.physics.secondquant import Commutator
>>> A, B = symbols('A,B', commutative=False)
>>> Commutator(B, A)
-Commutator(A, B)
Evaluate the commutator with .doit()
>>> comm = Commutator(A,B); comm
Commutator(A, B)
>>> comm.doit()
A*B - B*A
For two second quantization operators the commutator is evaluated
immediately:
>>> from sympy.physics.secondquant import Fd, F
>>> a = symbols('a', above_fermi=True)
>>> i = symbols('i', below_fermi=True)
>>> p,q = symbols('p,q')
>>> Commutator(Fd(a),Fd(i))
2*NO(CreateFermion(a)*CreateFermion(i))
But for more complicated expressions, the evaluation is triggered by
a call to .doit()
>>> comm = Commutator(Fd(p)*Fd(q),F(i)); comm
Commutator(CreateFermion(p)*CreateFermion(q), AnnihilateFermion(i))
>>> comm.doit(wicks=True)
-KroneckerDelta(i, p)*CreateFermion(q) +
KroneckerDelta(i, q)*CreateFermion(p)
"""
is_commutative = False
@classmethod
def eval(cls, a, b):
"""
The Commutator [A,B] is on canonical form if A < B.
Examples
========
>>> from sympy.physics.secondquant import Commutator, F, Fd
>>> from sympy.abc import x
>>> c1 = Commutator(F(x), Fd(x))
>>> c2 = Commutator(Fd(x), F(x))
>>> Commutator.eval(c1, c2)
0
"""
if not (a and b):
return S.Zero
if a == b:
return S.Zero
if a.is_commutative or b.is_commutative:
return S.Zero
#
# [A+B,C] -> [A,C] + [B,C]
#
a = a.expand()
if isinstance(a, Add):
return Add(*[cls(term, b) for term in a.args])
b = b.expand()
if isinstance(b, Add):
return Add(*[cls(a, term) for term in b.args])
#
# [xA,yB] -> xy*[A,B]
#
ca, nca = a.args_cnc()
cb, ncb = b.args_cnc()
c_part = list(ca) + list(cb)
if c_part:
return Mul(Mul(*c_part), cls(Mul._from_args(nca), Mul._from_args(ncb)))
#
# single second quantization operators
#
if isinstance(a, BosonicOperator) and isinstance(b, BosonicOperator):
if isinstance(b, CreateBoson) and isinstance(a, AnnihilateBoson):
return KroneckerDelta(a.state, b.state)
if isinstance(a, CreateBoson) and isinstance(b, AnnihilateBoson):
return S.NegativeOne*KroneckerDelta(a.state, b.state)
else:
return S.Zero
if isinstance(a, FermionicOperator) and isinstance(b, FermionicOperator):
return wicks(a*b) - wicks(b*a)
#
# Canonical ordering of arguments
#
if a.sort_key() > b.sort_key():
return S.NegativeOne*cls(b, a)
def doit(self, **hints):
"""
Enables the computation of complex expressions.
Examples
========
>>> from sympy.physics.secondquant import Commutator, F, Fd
>>> from sympy import symbols
>>> i, j = symbols('i,j', below_fermi=True)
>>> a, b = symbols('a,b', above_fermi=True)
>>> c = Commutator(Fd(a)*F(i),Fd(b)*F(j))
>>> c.doit(wicks=True)
0
"""
a = self.args[0]
b = self.args[1]
if hints.get("wicks"):
a = a.doit(**hints)
b = b.doit(**hints)
try:
return wicks(a*b) - wicks(b*a)
except ContractionAppliesOnlyToFermions:
pass
except WicksTheoremDoesNotApply:
pass
return (a*b - b*a).doit(**hints)
def __repr__(self):
return "Commutator(%s,%s)" % (self.args[0], self.args[1])
def __str__(self):
return "[%s,%s]" % (self.args[0], self.args[1])
def _latex(self, printer):
return "\\left[%s,%s\\right]" % tuple([
printer._print(arg) for arg in self.args])
class NO(Expr):
"""
This Object is used to represent normal ordering brackets.
i.e. {abcd} sometimes written :abcd:
Explanation
===========
Applying the function NO(arg) to an argument means that all operators in
the argument will be assumed to anticommute, and have vanishing
contractions. This allows an immediate reordering to canonical form
upon object creation.
Examples
========
>>> from sympy import symbols
>>> from sympy.physics.secondquant import NO, F, Fd
>>> p,q = symbols('p,q')
>>> NO(Fd(p)*F(q))
NO(CreateFermion(p)*AnnihilateFermion(q))
>>> NO(F(q)*Fd(p))
-NO(CreateFermion(p)*AnnihilateFermion(q))
Note
====
If you want to generate a normal ordered equivalent of an expression, you
should use the function wicks(). This class only indicates that all
operators inside the brackets anticommute, and have vanishing contractions.
Nothing more, nothing less.
"""
is_commutative = False
def __new__(cls, arg):
"""
Use anticommutation to get canonical form of operators.
Explanation
===========
Employ associativity of normal ordered product: {ab{cd}} = {abcd}
but note that {ab}{cd} /= {abcd}.
We also employ distributivity: {ab + cd} = {ab} + {cd}.
Canonical form also implies expand() {ab(c+d)} = {abc} + {abd}.
"""
# {ab + cd} = {ab} + {cd}
arg = sympify(arg)
arg = arg.expand()
if arg.is_Add:
return Add(*[ cls(term) for term in arg.args])
if arg.is_Mul:
# take coefficient outside of normal ordering brackets
c_part, seq = arg.args_cnc()
if c_part:
coeff = Mul(*c_part)
if not seq:
return coeff
else:
coeff = S.One
# {ab{cd}} = {abcd}
newseq = []
foundit = False
for fac in seq:
if isinstance(fac, NO):
newseq.extend(fac.args)
foundit = True
else:
newseq.append(fac)
if foundit:
return coeff*cls(Mul(*newseq))
# We assume that the user don't mix B and F operators
if isinstance(seq[0], BosonicOperator):
raise NotImplementedError
try:
newseq, sign = _sort_anticommuting_fermions(seq)
except ViolationOfPauliPrinciple:
return S.Zero
if sign % 2:
return (S.NegativeOne*coeff)*cls(Mul(*newseq))
elif sign:
return coeff*cls(Mul(*newseq))
else:
pass # since sign==0, no permutations was necessary
# if we couldn't do anything with Mul object, we just
# mark it as normal ordered
if coeff != S.One:
return coeff*cls(Mul(*newseq))
return Expr.__new__(cls, Mul(*newseq))
if isinstance(arg, NO):
return arg
# if object was not Mul or Add, normal ordering does not apply
return arg
@property
def has_q_creators(self):
"""
Return 0 if the leftmost argument of the first argument is a not a
q_creator, else 1 if it is above fermi or -1 if it is below fermi.
Examples
========
>>> from sympy import symbols
>>> from sympy.physics.secondquant import NO, F, Fd
>>> a = symbols('a', above_fermi=True)
>>> i = symbols('i', below_fermi=True)
>>> NO(Fd(a)*Fd(i)).has_q_creators
1
>>> NO(F(i)*F(a)).has_q_creators
-1
>>> NO(Fd(i)*F(a)).has_q_creators #doctest: +SKIP
0
"""
return self.args[0].args[0].is_q_creator
@property
def has_q_annihilators(self):
"""
Return 0 if the rightmost argument of the first argument is a not a
q_annihilator, else 1 if it is above fermi or -1 if it is below fermi.
Examples
========
>>> from sympy import symbols
>>> from sympy.physics.secondquant import NO, F, Fd
>>> a = symbols('a', above_fermi=True)
>>> i = symbols('i', below_fermi=True)
>>> NO(Fd(a)*Fd(i)).has_q_annihilators
-1
>>> NO(F(i)*F(a)).has_q_annihilators
1
>>> NO(Fd(a)*F(i)).has_q_annihilators
0
"""
return self.args[0].args[-1].is_q_annihilator
def doit(self, **hints):
"""
Either removes the brackets or enables complex computations
in its arguments.
Examples
========
>>> from sympy.physics.secondquant import NO, Fd, F
>>> from textwrap import fill
>>> from sympy import symbols, Dummy
>>> p,q = symbols('p,q', cls=Dummy)
>>> print(fill(str(NO(Fd(p)*F(q)).doit())))
KroneckerDelta(_a, _p)*KroneckerDelta(_a,
_q)*CreateFermion(_a)*AnnihilateFermion(_a) + KroneckerDelta(_a,
_p)*KroneckerDelta(_i, _q)*CreateFermion(_a)*AnnihilateFermion(_i) -
KroneckerDelta(_a, _q)*KroneckerDelta(_i,
_p)*AnnihilateFermion(_a)*CreateFermion(_i) - KroneckerDelta(_i,
_p)*KroneckerDelta(_i, _q)*AnnihilateFermion(_i)*CreateFermion(_i)
"""
if hints.get("remove_brackets", True):
return self._remove_brackets()
else:
return self.__new__(type(self), self.args[0].doit(**hints))
def _remove_brackets(self):
"""
Returns the sorted string without normal order brackets.
The returned string have the property that no nonzero
contractions exist.
"""
# check if any creator is also an annihilator
subslist = []
for i in self.iter_q_creators():
if self[i].is_q_annihilator:
assume = self[i].state.assumptions0
# only operators with a dummy index can be split in two terms
if isinstance(self[i].state, Dummy):
# create indices with fermi restriction
assume.pop("above_fermi", None)
assume["below_fermi"] = True
below = Dummy('i', **assume)
assume.pop("below_fermi", None)
assume["above_fermi"] = True
above = Dummy('a', **assume)
cls = type(self[i])
split = (
self[i].__new__(cls, below)
* KroneckerDelta(below, self[i].state)
+ self[i].__new__(cls, above)
* KroneckerDelta(above, self[i].state)
)
subslist.append((self[i], split))
else:
raise SubstitutionOfAmbigousOperatorFailed(self[i])
if subslist:
result = NO(self.subs(subslist))
if isinstance(result, Add):
return Add(*[term.doit() for term in result.args])
else:
return self.args[0]
def _expand_operators(self):
"""
Returns a sum of NO objects that contain no ambiguous q-operators.
Explanation
===========
If an index q has range both above and below fermi, the operator F(q)
is ambiguous in the sense that it can be both a q-creator and a q-annihilator.
If q is dummy, it is assumed to be a summation variable and this method
rewrites it into a sum of NO terms with unambiguous operators:
{Fd(p)*F(q)} = {Fd(a)*F(b)} + {Fd(a)*F(i)} + {Fd(j)*F(b)} -{F(i)*Fd(j)}
where a,b are above and i,j are below fermi level.
"""
return NO(self._remove_brackets)
def __getitem__(self, i):
if isinstance(i, slice):
indices = i.indices(len(self))
return [self.args[0].args[i] for i in range(*indices)]
else:
return self.args[0].args[i]
def __len__(self):
return len(self.args[0].args)
def iter_q_annihilators(self):
"""
Iterates over the annihilation operators.
Examples
========
>>> from sympy import symbols
>>> i, j = symbols('i j', below_fermi=True)
>>> a, b = symbols('a b', above_fermi=True)
>>> from sympy.physics.secondquant import NO, F, Fd
>>> no = NO(Fd(a)*F(i)*F(b)*Fd(j))
>>> no.iter_q_creators()
<generator object... at 0x...>
>>> list(no.iter_q_creators())
[0, 1]
>>> list(no.iter_q_annihilators())
[3, 2]
"""
ops = self.args[0].args
iter = range(len(ops) - 1, -1, -1)
for i in iter:
if ops[i].is_q_annihilator:
yield i
else:
break
def iter_q_creators(self):
"""
Iterates over the creation operators.
Examples
========
>>> from sympy import symbols
>>> i, j = symbols('i j', below_fermi=True)
>>> a, b = symbols('a b', above_fermi=True)
>>> from sympy.physics.secondquant import NO, F, Fd
>>> no = NO(Fd(a)*F(i)*F(b)*Fd(j))
>>> no.iter_q_creators()
<generator object... at 0x...>
>>> list(no.iter_q_creators())
[0, 1]
>>> list(no.iter_q_annihilators())
[3, 2]
"""
ops = self.args[0].args
iter = range(0, len(ops))
for i in iter:
if ops[i].is_q_creator:
yield i
else:
break
def get_subNO(self, i):
"""
Returns a NO() without FermionicOperator at index i.
Examples
========
>>> from sympy import symbols
>>> from sympy.physics.secondquant import F, NO
>>> p, q, r = symbols('p,q,r')
>>> NO(F(p)*F(q)*F(r)).get_subNO(1)
NO(AnnihilateFermion(p)*AnnihilateFermion(r))
"""
arg0 = self.args[0] # it's a Mul by definition of how it's created
mul = arg0._new_rawargs(*(arg0.args[:i] + arg0.args[i + 1:]))
return NO(mul)
def _latex(self, printer):
return "\\left\\{%s\\right\\}" % printer._print(self.args[0])
def __repr__(self):
return "NO(%s)" % self.args[0]
def __str__(self):
return ":%s:" % self.args[0]
def contraction(a, b):
"""
Calculates contraction of Fermionic operators a and b.
Examples
========
>>> from sympy import symbols
>>> from sympy.physics.secondquant import F, Fd, contraction
>>> p, q = symbols('p,q')
>>> a, b = symbols('a,b', above_fermi=True)
>>> i, j = symbols('i,j', below_fermi=True)
A contraction is non-zero only if a quasi-creator is to the right of a
quasi-annihilator:
>>> contraction(F(a),Fd(b))
KroneckerDelta(a, b)
>>> contraction(Fd(i),F(j))
KroneckerDelta(i, j)
For general indices a non-zero result restricts the indices to below/above
the fermi surface:
>>> contraction(Fd(p),F(q))
KroneckerDelta(_i, q)*KroneckerDelta(p, q)
>>> contraction(F(p),Fd(q))
KroneckerDelta(_a, q)*KroneckerDelta(p, q)
Two creators or two annihilators always vanishes:
>>> contraction(F(p),F(q))
0
>>> contraction(Fd(p),Fd(q))
0
"""
if isinstance(b, FermionicOperator) and isinstance(a, FermionicOperator):
if isinstance(a, AnnihilateFermion) and isinstance(b, CreateFermion):
if b.state.assumptions0.get("below_fermi"):
return S.Zero
if a.state.assumptions0.get("below_fermi"):
return S.Zero
if b.state.assumptions0.get("above_fermi"):
return KroneckerDelta(a.state, b.state)
if a.state.assumptions0.get("above_fermi"):
return KroneckerDelta(a.state, b.state)
return (KroneckerDelta(a.state, b.state)*
KroneckerDelta(b.state, Dummy('a', above_fermi=True)))
if isinstance(b, AnnihilateFermion) and isinstance(a, CreateFermion):
if b.state.assumptions0.get("above_fermi"):
return S.Zero
if a.state.assumptions0.get("above_fermi"):
return S.Zero
if b.state.assumptions0.get("below_fermi"):
return KroneckerDelta(a.state, b.state)
if a.state.assumptions0.get("below_fermi"):
return KroneckerDelta(a.state, b.state)
return (KroneckerDelta(a.state, b.state)*
KroneckerDelta(b.state, Dummy('i', below_fermi=True)))
# vanish if 2xAnnihilator or 2xCreator
return S.Zero
else:
#not fermion operators
t = ( isinstance(i, FermionicOperator) for i in (a, b) )
raise ContractionAppliesOnlyToFermions(*t)
def _sqkey(sq_operator):
"""Generates key for canonical sorting of SQ operators."""
return sq_operator._sortkey()
def _sort_anticommuting_fermions(string1, key=_sqkey):
"""Sort fermionic operators to canonical order, assuming all pairs anticommute.
Explanation
===========
Uses a bidirectional bubble sort. Items in string1 are not referenced
so in principle they may be any comparable objects. The sorting depends on the
operators '>' and '=='.
If the Pauli principle is violated, an exception is raised.
Returns
=======
tuple (sorted_str, sign)
sorted_str: list containing the sorted operators
sign: int telling how many times the sign should be changed
(if sign==0 the string was already sorted)
"""
verified = False
sign = 0
rng = list(range(len(string1) - 1))
rev = list(range(len(string1) - 3, -1, -1))
keys = list(map(key, string1))
key_val = dict(list(zip(keys, string1)))
while not verified:
verified = True
for i in rng:
left = keys[i]
right = keys[i + 1]
if left == right:
raise ViolationOfPauliPrinciple([left, right])
if left > right:
verified = False
keys[i:i + 2] = [right, left]
sign = sign + 1
if verified:
break
for i in rev:
left = keys[i]
right = keys[i + 1]
if left == right:
raise ViolationOfPauliPrinciple([left, right])
if left > right:
verified = False
keys[i:i + 2] = [right, left]
sign = sign + 1
string1 = [ key_val[k] for k in keys ]
return (string1, sign)
def evaluate_deltas(e):
"""
We evaluate KroneckerDelta symbols in the expression assuming Einstein summation.
Explanation
===========
If one index is repeated it is summed over and in effect substituted with
the other one. If both indices are repeated we substitute according to what
is the preferred index. this is determined by
KroneckerDelta.preferred_index and KroneckerDelta.killable_index.
In case there are no possible substitutions or if a substitution would
imply a loss of information, nothing is done.
In case an index appears in more than one KroneckerDelta, the resulting
substitution depends on the order of the factors. Since the ordering is platform
dependent, the literal expression resulting from this function may be hard to
predict.
Examples
========
We assume the following:
>>> from sympy import symbols, Function, Dummy, KroneckerDelta
>>> from sympy.physics.secondquant import evaluate_deltas
>>> i,j = symbols('i j', below_fermi=True, cls=Dummy)
>>> a,b = symbols('a b', above_fermi=True, cls=Dummy)
>>> p,q = symbols('p q', cls=Dummy)
>>> f = Function('f')
>>> t = Function('t')
The order of preference for these indices according to KroneckerDelta is
(a, b, i, j, p, q).
Trivial cases:
>>> evaluate_deltas(KroneckerDelta(i,j)*f(i)) # d_ij f(i) -> f(j)
f(_j)
>>> evaluate_deltas(KroneckerDelta(i,j)*f(j)) # d_ij f(j) -> f(i)
f(_i)
>>> evaluate_deltas(KroneckerDelta(i,p)*f(p)) # d_ip f(p) -> f(i)
f(_i)
>>> evaluate_deltas(KroneckerDelta(q,p)*f(p)) # d_qp f(p) -> f(q)
f(_q)
>>> evaluate_deltas(KroneckerDelta(q,p)*f(q)) # d_qp f(q) -> f(p)
f(_p)
More interesting cases:
>>> evaluate_deltas(KroneckerDelta(i,p)*t(a,i)*f(p,q))
f(_i, _q)*t(_a, _i)
>>> evaluate_deltas(KroneckerDelta(a,p)*t(a,i)*f(p,q))
f(_a, _q)*t(_a, _i)
>>> evaluate_deltas(KroneckerDelta(p,q)*f(p,q))
f(_p, _p)
Finally, here are some cases where nothing is done, because that would
imply a loss of information:
>>> evaluate_deltas(KroneckerDelta(i,p)*f(q))
f(_q)*KroneckerDelta(_i, _p)
>>> evaluate_deltas(KroneckerDelta(i,p)*f(i))
f(_i)*KroneckerDelta(_i, _p)
"""
# We treat Deltas only in mul objects
# for general function objects we don't evaluate KroneckerDeltas in arguments,
# but here we hard code exceptions to this rule
accepted_functions = (
Add,
)
if isinstance(e, accepted_functions):
return e.func(*[evaluate_deltas(arg) for arg in e.args])
elif isinstance(e, Mul):
# find all occurrences of delta function and count each index present in
# expression.
deltas = []
indices = {}
for i in e.args:
for s in i.free_symbols:
if s in indices:
indices[s] += 1
else:
indices[s] = 0 # geek counting simplifies logic below
if isinstance(i, KroneckerDelta):
deltas.append(i)
for d in deltas:
# If we do something, and there are more deltas, we should recurse
# to treat the resulting expression properly
if d.killable_index.is_Symbol and indices[d.killable_index]:
e = e.subs(d.killable_index, d.preferred_index)
if len(deltas) > 1:
return evaluate_deltas(e)
elif (d.preferred_index.is_Symbol and indices[d.preferred_index]
and d.indices_contain_equal_information):
e = e.subs(d.preferred_index, d.killable_index)
if len(deltas) > 1:
return evaluate_deltas(e)
else:
pass
return e
# nothing to do, maybe we hit a Symbol or a number
else:
return e
def substitute_dummies(expr, new_indices=False, pretty_indices={}):
"""
Collect terms by substitution of dummy variables.
Explanation
===========
This routine allows simplification of Add expressions containing terms
which differ only due to dummy variables.
The idea is to substitute all dummy variables consistently depending on
the structure of the term. For each term, we obtain a sequence of all
dummy variables, where the order is determined by the index range, what
factors the index belongs to and its position in each factor. See
_get_ordered_dummies() for more information about the sorting of dummies.
The index sequence is then substituted consistently in each term.
Examples
========
>>> from sympy import symbols, Function, Dummy
>>> from sympy.physics.secondquant import substitute_dummies
>>> a,b,c,d = symbols('a b c d', above_fermi=True, cls=Dummy)
>>> i,j = symbols('i j', below_fermi=True, cls=Dummy)
>>> f = Function('f')
>>> expr = f(a,b) + f(c,d); expr
f(_a, _b) + f(_c, _d)
Since a, b, c and d are equivalent summation indices, the expression can be
simplified to a single term (for which the dummy indices are still summed over)
>>> substitute_dummies(expr)
2*f(_a, _b)
Controlling output:
By default the dummy symbols that are already present in the expression
will be reused in a different permutation. However, if new_indices=True,
new dummies will be generated and inserted. The keyword 'pretty_indices'
can be used to control this generation of new symbols.
By default the new dummies will be generated on the form i_1, i_2, a_1,
etc. If you supply a dictionary with key:value pairs in the form:
{ index_group: string_of_letters }
The letters will be used as labels for the new dummy symbols. The
index_groups must be one of 'above', 'below' or 'general'.
>>> expr = f(a,b,i,j)
>>> my_dummies = { 'above':'st', 'below':'uv' }
>>> substitute_dummies(expr, new_indices=True, pretty_indices=my_dummies)
f(_s, _t, _u, _v)
If we run out of letters, or if there is no keyword for some index_group
the default dummy generator will be used as a fallback:
>>> p,q = symbols('p q', cls=Dummy) # general indices
>>> expr = f(p,q)
>>> substitute_dummies(expr, new_indices=True, pretty_indices=my_dummies)
f(_p_0, _p_1)
"""
# setup the replacing dummies
if new_indices:
letters_above = pretty_indices.get('above', "")
letters_below = pretty_indices.get('below', "")
letters_general = pretty_indices.get('general', "")
len_above = len(letters_above)
len_below = len(letters_below)
len_general = len(letters_general)
def _i(number):
try:
return letters_below[number]
except IndexError:
return 'i_' + str(number - len_below)
def _a(number):
try:
return letters_above[number]
except IndexError:
return 'a_' + str(number - len_above)
def _p(number):
try:
return letters_general[number]
except IndexError:
return 'p_' + str(number - len_general)
aboves = []
belows = []
generals = []
dummies = expr.atoms(Dummy)
if not new_indices:
dummies = sorted(dummies, key=default_sort_key)
# generate lists with the dummies we will insert
a = i = p = 0
for d in dummies:
assum = d.assumptions0
if assum.get("above_fermi"):
if new_indices:
sym = _a(a)
a += 1
l1 = aboves
elif assum.get("below_fermi"):
if new_indices:
sym = _i(i)
i += 1
l1 = belows
else:
if new_indices:
sym = _p(p)
p += 1
l1 = generals
if new_indices:
l1.append(Dummy(sym, **assum))
else:
l1.append(d)
expr = expr.expand()
terms = Add.make_args(expr)
new_terms = []
for term in terms:
i = iter(belows)
a = iter(aboves)
p = iter(generals)
ordered = _get_ordered_dummies(term)
subsdict = {}
for d in ordered:
if d.assumptions0.get('below_fermi'):
subsdict[d] = next(i)
elif d.assumptions0.get('above_fermi'):
subsdict[d] = next(a)
else:
subsdict[d] = next(p)
subslist = []
final_subs = []
for k, v in subsdict.items():
if k == v:
continue
if v in subsdict:
# We check if the sequence of substitutions end quickly. In
# that case, we can avoid temporary symbols if we ensure the
# correct substitution order.
if subsdict[v] in subsdict:
# (x, y) -> (y, x), we need a temporary variable
x = Dummy('x')
subslist.append((k, x))
final_subs.append((x, v))
else:
# (x, y) -> (y, a), x->y must be done last
# but before temporary variables are resolved
final_subs.insert(0, (k, v))
else:
subslist.append((k, v))
subslist.extend(final_subs)
new_terms.append(term.subs(subslist))
return Add(*new_terms)
class KeyPrinter(StrPrinter):
"""Printer for which only equal objects are equal in print"""
def _print_Dummy(self, expr):
return "(%s_%i)" % (expr.name, expr.dummy_index)
def __kprint(expr):
p = KeyPrinter()
return p.doprint(expr)
def _get_ordered_dummies(mul, verbose=False):
"""Returns all dummies in the mul sorted in canonical order.
Explanation
===========
The purpose of the canonical ordering is that dummies can be substituted
consistently across terms with the result that equivalent terms can be
simplified.
It is not possible to determine if two terms are equivalent based solely on
the dummy order. However, a consistent substitution guided by the ordered
dummies should lead to trivially (non-)equivalent terms, thereby revealing
the equivalence. This also means that if two terms have identical sequences of
dummies, the (non-)equivalence should already be apparent.
Strategy
--------
The canonical order is given by an arbitrary sorting rule. A sort key
is determined for each dummy as a tuple that depends on all factors where
the index is present. The dummies are thereby sorted according to the
contraction structure of the term, instead of sorting based solely on the
dummy symbol itself.
After all dummies in the term has been assigned a key, we check for identical
keys, i.e. unorderable dummies. If any are found, we call a specialized
method, _determine_ambiguous(), that will determine a unique order based
on recursive calls to _get_ordered_dummies().
Key description
---------------
A high level description of the sort key:
1. Range of the dummy index
2. Relation to external (non-dummy) indices
3. Position of the index in the first factor
4. Position of the index in the second factor
The sort key is a tuple with the following components:
1. A single character indicating the range of the dummy (above, below
or general.)
2. A list of strings with fully masked string representations of all
factors where the dummy is present. By masked, we mean that dummies
are represented by a symbol to indicate either below fermi, above or
general. No other information is displayed about the dummies at
this point. The list is sorted stringwise.
3. An integer number indicating the position of the index, in the first
factor as sorted in 2.
4. An integer number indicating the position of the index, in the second
factor as sorted in 2.
If a factor is either of type AntiSymmetricTensor or SqOperator, the index
position in items 3 and 4 is indicated as 'upper' or 'lower' only.
(Creation operators are considered upper and annihilation operators lower.)
If the masked factors are identical, the two factors cannot be ordered
unambiguously in item 2. In this case, items 3, 4 are left out. If several
indices are contracted between the unorderable factors, it will be handled by
_determine_ambiguous()
"""
# setup dicts to avoid repeated calculations in key()
args = Mul.make_args(mul)
fac_dum = { fac: fac.atoms(Dummy) for fac in args }
fac_repr = { fac: __kprint(fac) for fac in args }
all_dums = set().union(*fac_dum.values())
mask = {}
for d in all_dums:
if d.assumptions0.get('below_fermi'):
mask[d] = '0'
elif d.assumptions0.get('above_fermi'):
mask[d] = '1'
else:
mask[d] = '2'
dum_repr = {d: __kprint(d) for d in all_dums}
def _key(d):
dumstruct = [ fac for fac in fac_dum if d in fac_dum[fac] ]
other_dums = set().union(*[fac_dum[fac] for fac in dumstruct])
fac = dumstruct[-1]
if other_dums is fac_dum[fac]:
other_dums = fac_dum[fac].copy()
other_dums.remove(d)
masked_facs = [ fac_repr[fac] for fac in dumstruct ]
for d2 in other_dums:
masked_facs = [ fac.replace(dum_repr[d2], mask[d2])
for fac in masked_facs ]
all_masked = [ fac.replace(dum_repr[d], mask[d])
for fac in masked_facs ]
masked_facs = dict(list(zip(dumstruct, masked_facs)))
# dummies for which the ordering cannot be determined
if has_dups(all_masked):
all_masked.sort()
return mask[d], tuple(all_masked) # positions are ambiguous
# sort factors according to fully masked strings
keydict = dict(list(zip(dumstruct, all_masked)))
dumstruct.sort(key=lambda x: keydict[x])
all_masked.sort()
pos_val = []
for fac in dumstruct:
if isinstance(fac, AntiSymmetricTensor):
if d in fac.upper:
pos_val.append('u')
if d in fac.lower:
pos_val.append('l')
elif isinstance(fac, Creator):
pos_val.append('u')
elif isinstance(fac, Annihilator):
pos_val.append('l')
elif isinstance(fac, NO):
ops = [ op for op in fac if op.has(d) ]
for op in ops:
if isinstance(op, Creator):
pos_val.append('u')
else:
pos_val.append('l')
else:
# fallback to position in string representation
facpos = -1
while 1:
facpos = masked_facs[fac].find(dum_repr[d], facpos + 1)
if facpos == -1:
break
pos_val.append(facpos)
return (mask[d], tuple(all_masked), pos_val[0], pos_val[-1])
dumkey = dict(list(zip(all_dums, list(map(_key, all_dums)))))
result = sorted(all_dums, key=lambda x: dumkey[x])
if has_dups(iter(dumkey.values())):
# We have ambiguities
unordered = defaultdict(set)
for d, k in dumkey.items():
unordered[k].add(d)
for k in [ k for k in unordered if len(unordered[k]) < 2 ]:
del unordered[k]
unordered = [ unordered[k] for k in sorted(unordered) ]
result = _determine_ambiguous(mul, result, unordered)
return result
def _determine_ambiguous(term, ordered, ambiguous_groups):
# We encountered a term for which the dummy substitution is ambiguous.
# This happens for terms with 2 or more contractions between factors that
# cannot be uniquely ordered independent of summation indices. For
# example:
#
# Sum(p, q) v^{p, .}_{q, .}v^{q, .}_{p, .}
#
# Assuming that the indices represented by . are dummies with the
# same range, the factors cannot be ordered, and there is no
# way to determine a consistent ordering of p and q.
#
# The strategy employed here, is to relabel all unambiguous dummies with
# non-dummy symbols and call _get_ordered_dummies again. This procedure is
# applied to the entire term so there is a possibility that
# _determine_ambiguous() is called again from a deeper recursion level.
# break recursion if there are no ordered dummies
all_ambiguous = set()
for dummies in ambiguous_groups:
all_ambiguous |= dummies
all_ordered = set(ordered) - all_ambiguous
if not all_ordered:
# FIXME: If we arrive here, there are no ordered dummies. A method to
# handle this needs to be implemented. In order to return something
# useful nevertheless, we choose arbitrarily the first dummy and
# determine the rest from this one. This method is dependent on the
# actual dummy labels which violates an assumption for the
# canonicalization procedure. A better implementation is needed.
group = [ d for d in ordered if d in ambiguous_groups[0] ]
d = group[0]
all_ordered.add(d)
ambiguous_groups[0].remove(d)
stored_counter = _symbol_factory._counter
subslist = []
for d in [ d for d in ordered if d in all_ordered ]:
nondum = _symbol_factory._next()
subslist.append((d, nondum))
newterm = term.subs(subslist)
neworder = _get_ordered_dummies(newterm)
_symbol_factory._set_counter(stored_counter)
# update ordered list with new information
for group in ambiguous_groups:
ordered_group = [ d for d in neworder if d in group ]
ordered_group.reverse()
result = []
for d in ordered:
if d in group:
result.append(ordered_group.pop())
else:
result.append(d)
ordered = result
return ordered
class _SymbolFactory:
def __init__(self, label):
self._counterVar = 0
self._label = label
def _set_counter(self, value):
"""
Sets counter to value.
"""
self._counterVar = value
@property
def _counter(self):
"""
What counter is currently at.
"""
return self._counterVar
def _next(self):
"""
Generates the next symbols and increments counter by 1.
"""
s = Symbol("%s%i" % (self._label, self._counterVar))
self._counterVar += 1
return s
_symbol_factory = _SymbolFactory('_]"]_') # most certainly a unique label
@cacheit
def _get_contractions(string1, keep_only_fully_contracted=False):
"""
Returns Add-object with contracted terms.
Uses recursion to find all contractions. -- Internal helper function --
Will find nonzero contractions in string1 between indices given in
leftrange and rightrange.
"""
# Should we store current level of contraction?
if keep_only_fully_contracted and string1:
result = []
else:
result = [NO(Mul(*string1))]
for i in range(len(string1) - 1):
for j in range(i + 1, len(string1)):
c = contraction(string1[i], string1[j])
if c:
sign = (j - i + 1) % 2
if sign:
coeff = S.NegativeOne*c
else:
coeff = c
#
# Call next level of recursion
# ============================
#
# We now need to find more contractions among operators
#
# oplist = string1[:i]+ string1[i+1:j] + string1[j+1:]
#
# To prevent overcounting, we don't allow contractions
# we have already encountered. i.e. contractions between
# string1[:i] <---> string1[i+1:j]
# and string1[:i] <---> string1[j+1:].
#
# This leaves the case:
oplist = string1[i + 1:j] + string1[j + 1:]
if oplist:
result.append(coeff*NO(
Mul(*string1[:i])*_get_contractions( oplist,
keep_only_fully_contracted=keep_only_fully_contracted)))
else:
result.append(coeff*NO( Mul(*string1[:i])))
if keep_only_fully_contracted:
break # next iteration over i leaves leftmost operator string1[0] uncontracted
return Add(*result)
def wicks(e, **kw_args):
"""
Returns the normal ordered equivalent of an expression using Wicks Theorem.
Examples
========
>>> from sympy import symbols, Dummy
>>> from sympy.physics.secondquant import wicks, F, Fd
>>> p, q, r = symbols('p,q,r')
>>> wicks(Fd(p)*F(q))
KroneckerDelta(_i, q)*KroneckerDelta(p, q) + NO(CreateFermion(p)*AnnihilateFermion(q))
By default, the expression is expanded:
>>> wicks(F(p)*(F(q)+F(r)))
NO(AnnihilateFermion(p)*AnnihilateFermion(q)) + NO(AnnihilateFermion(p)*AnnihilateFermion(r))
With the keyword 'keep_only_fully_contracted=True', only fully contracted
terms are returned.
By request, the result can be simplified in the following order:
-- KroneckerDelta functions are evaluated
-- Dummy variables are substituted consistently across terms
>>> p, q, r = symbols('p q r', cls=Dummy)
>>> wicks(Fd(p)*(F(q)+F(r)), keep_only_fully_contracted=True)
KroneckerDelta(_i, _q)*KroneckerDelta(_p, _q) + KroneckerDelta(_i, _r)*KroneckerDelta(_p, _r)
"""
if not e:
return S.Zero
opts = {
'simplify_kronecker_deltas': False,
'expand': True,
'simplify_dummies': False,
'keep_only_fully_contracted': False
}
opts.update(kw_args)
# check if we are already normally ordered
if isinstance(e, NO):
if opts['keep_only_fully_contracted']:
return S.Zero
else:
return e
elif isinstance(e, FermionicOperator):
if opts['keep_only_fully_contracted']:
return S.Zero
else:
return e
# break up any NO-objects, and evaluate commutators
e = e.doit(wicks=True)
# make sure we have only one term to consider
e = e.expand()
if isinstance(e, Add):
if opts['simplify_dummies']:
return substitute_dummies(Add(*[ wicks(term, **kw_args) for term in e.args]))
else:
return Add(*[ wicks(term, **kw_args) for term in e.args])
# For Mul-objects we can actually do something
if isinstance(e, Mul):
# we don't want to mess around with commuting part of Mul
# so we factorize it out before starting recursion
c_part = []
string1 = []
for factor in e.args:
if factor.is_commutative:
c_part.append(factor)
else:
string1.append(factor)
n = len(string1)
# catch trivial cases
if n == 0:
result = e
elif n == 1:
if opts['keep_only_fully_contracted']:
return S.Zero
else:
result = e
else: # non-trivial
if isinstance(string1[0], BosonicOperator):
raise NotImplementedError
string1 = tuple(string1)
# recursion over higher order contractions
result = _get_contractions(string1,
keep_only_fully_contracted=opts['keep_only_fully_contracted'] )
result = Mul(*c_part)*result
if opts['expand']:
result = result.expand()
if opts['simplify_kronecker_deltas']:
result = evaluate_deltas(result)
return result
# there was nothing to do
return e
class PermutationOperator(Expr):
"""
Represents the index permutation operator P(ij).
P(ij)*f(i)*g(j) = f(i)*g(j) - f(j)*g(i)
"""
is_commutative = True
def __new__(cls, i, j):
i, j = sorted(map(sympify, (i, j)), key=default_sort_key)
obj = Basic.__new__(cls, i, j)
return obj
def get_permuted(self, expr):
"""
Returns -expr with permuted indices.
Explanation
===========
>>> from sympy import symbols, Function
>>> from sympy.physics.secondquant import PermutationOperator
>>> p,q = symbols('p,q')
>>> f = Function('f')
>>> PermutationOperator(p,q).get_permuted(f(p,q))
-f(q, p)
"""
i = self.args[0]
j = self.args[1]
if expr.has(i) and expr.has(j):
tmp = Dummy()
expr = expr.subs(i, tmp)
expr = expr.subs(j, i)
expr = expr.subs(tmp, j)
return S.NegativeOne*expr
else:
return expr
def _latex(self, printer):
return "P(%s%s)" % self.args
def simplify_index_permutations(expr, permutation_operators):
"""
Performs simplification by introducing PermutationOperators where appropriate.
Explanation
===========
Schematically:
[abij] - [abji] - [baij] + [baji] -> P(ab)*P(ij)*[abij]
permutation_operators is a list of PermutationOperators to consider.
If permutation_operators=[P(ab),P(ij)] we will try to introduce the
permutation operators P(ij) and P(ab) in the expression. If there are other
possible simplifications, we ignore them.
>>> from sympy import symbols, Function
>>> from sympy.physics.secondquant import simplify_index_permutations
>>> from sympy.physics.secondquant import PermutationOperator
>>> p,q,r,s = symbols('p,q,r,s')
>>> f = Function('f')
>>> g = Function('g')
>>> expr = f(p)*g(q) - f(q)*g(p); expr
f(p)*g(q) - f(q)*g(p)
>>> simplify_index_permutations(expr,[PermutationOperator(p,q)])
f(p)*g(q)*PermutationOperator(p, q)
>>> PermutList = [PermutationOperator(p,q),PermutationOperator(r,s)]
>>> expr = f(p,r)*g(q,s) - f(q,r)*g(p,s) + f(q,s)*g(p,r) - f(p,s)*g(q,r)
>>> simplify_index_permutations(expr,PermutList)
f(p, r)*g(q, s)*PermutationOperator(p, q)*PermutationOperator(r, s)
"""
def _get_indices(expr, ind):
"""
Collects indices recursively in predictable order.
"""
result = []
for arg in expr.args:
if arg in ind:
result.append(arg)
else:
if arg.args:
result.extend(_get_indices(arg, ind))
return result
def _choose_one_to_keep(a, b, ind):
# we keep the one where indices in ind are in order ind[0] < ind[1]
return min(a, b, key=lambda x: default_sort_key(_get_indices(x, ind)))
expr = expr.expand()
if isinstance(expr, Add):
terms = set(expr.args)
for P in permutation_operators:
new_terms = set()
on_hold = set()
while terms:
term = terms.pop()
permuted = P.get_permuted(term)
if permuted in terms | on_hold:
try:
terms.remove(permuted)
except KeyError:
on_hold.remove(permuted)
keep = _choose_one_to_keep(term, permuted, P.args)
new_terms.add(P*keep)
else:
# Some terms must get a second chance because the permuted
# term may already have canonical dummy ordering. Then
# substitute_dummies() does nothing. However, the other
# term, if it exists, will be able to match with us.
permuted1 = permuted
permuted = substitute_dummies(permuted)
if permuted1 == permuted:
on_hold.add(term)
elif permuted in terms | on_hold:
try:
terms.remove(permuted)
except KeyError:
on_hold.remove(permuted)
keep = _choose_one_to_keep(term, permuted, P.args)
new_terms.add(P*keep)
else:
new_terms.add(term)
terms = new_terms | on_hold
return Add(*terms)
return expr
PK ]ZZZţ� � sympy/physics/sho.pyfrom sympy.core import S, pi, Rational
from sympy.functions import assoc_laguerre, sqrt, exp, factorial, factorial2
def R_nl(n, l, nu, r):
"""
Returns the radial wavefunction R_{nl} for a 3d isotropic harmonic
oscillator.
Parameters
==========
n :
The "nodal" quantum number. Corresponds to the number of nodes in
the wavefunction. ``n >= 0``
l :
The quantum number for orbital angular momentum.
nu :
mass-scaled frequency: nu = m*omega/(2*hbar) where `m` is the mass
and `omega` the frequency of the oscillator.
(in atomic units ``nu == omega/2``)
r :
Radial coordinate.
Examples
========
>>> from sympy.physics.sho import R_nl
>>> from sympy.abc import r, nu, l
>>> R_nl(0, 0, 1, r)
2*2**(3/4)*exp(-r**2)/pi**(1/4)
>>> R_nl(1, 0, 1, r)
4*2**(1/4)*sqrt(3)*(3/2 - 2*r**2)*exp(-r**2)/(3*pi**(1/4))
l, nu and r may be symbolic:
>>> R_nl(0, 0, nu, r)
2*2**(3/4)*sqrt(nu**(3/2))*exp(-nu*r**2)/pi**(1/4)
>>> R_nl(0, l, 1, r)
r**l*sqrt(2**(l + 3/2)*2**(l + 2)/factorial2(2*l + 1))*exp(-r**2)/pi**(1/4)
The normalization of the radial wavefunction is:
>>> from sympy import Integral, oo
>>> Integral(R_nl(0, 0, 1, r)**2*r**2, (r, 0, oo)).n()
1.00000000000000
>>> Integral(R_nl(1, 0, 1, r)**2*r**2, (r, 0, oo)).n()
1.00000000000000
>>> Integral(R_nl(1, 1, 1, r)**2*r**2, (r, 0, oo)).n()
1.00000000000000
"""
n, l, nu, r = map(S, [n, l, nu, r])
# formula uses n >= 1 (instead of nodal n >= 0)
n = n + 1
C = sqrt(
((2*nu)**(l + Rational(3, 2))*2**(n + l + 1)*factorial(n - 1))/
(sqrt(pi)*(factorial2(2*n + 2*l - 1)))
)
return C*r**(l)*exp(-nu*r**2)*assoc_laguerre(n - 1, l + S.Half, 2*nu*r**2)
def E_nl(n, l, hw):
"""
Returns the Energy of an isotropic harmonic oscillator.
Parameters
==========
n :
The "nodal" quantum number.
l :
The orbital angular momentum.
hw :
The harmonic oscillator parameter.
Notes
=====
The unit of the returned value matches the unit of hw, since the energy is
calculated as:
E_nl = (2*n + l + 3/2)*hw
Examples
========
>>> from sympy.physics.sho import E_nl
>>> from sympy import symbols
>>> x, y, z = symbols('x, y, z')
>>> E_nl(x, y, z)
z*(2*x + y + 3/2)
"""
return (2*n + l + Rational(3, 2))*hw
PK ]ZZZ/�Z�2� 2� sympy/physics/wigner.py# -*- coding: utf-8 -*-
r"""
Wigner, Clebsch-Gordan, Racah, and Gaunt coefficients
Collection of functions for calculating Wigner 3j, 6j, 9j,
Clebsch-Gordan, Racah as well as Gaunt coefficients exactly, all
evaluating to a rational number times the square root of a rational
number [Rasch03]_.
Please see the description of the individual functions for further
details and examples.
References
==========
.. [Regge58] 'Symmetry Properties of Clebsch-Gordan Coefficients',
T. Regge, Nuovo Cimento, Volume 10, pp. 544 (1958)
.. [Regge59] 'Symmetry Properties of Racah Coefficients',
T. Regge, Nuovo Cimento, Volume 11, pp. 116 (1959)
.. [Edmonds74] A. R. Edmonds. Angular momentum in quantum mechanics.
Investigations in physics, 4.; Investigations in physics, no. 4.
Princeton, N.J., Princeton University Press, 1957.
.. [Rasch03] J. Rasch and A. C. H. Yu, 'Efficient Storage Scheme for
Pre-calculated Wigner 3j, 6j and Gaunt Coefficients', SIAM
J. Sci. Comput. Volume 25, Issue 4, pp. 1416-1428 (2003)
.. [Liberatodebrito82] 'FORTRAN program for the integral of three
spherical harmonics', A. Liberato de Brito,
Comput. Phys. Commun., Volume 25, pp. 81-85 (1982)
.. [Homeier96] 'Some Properties of the Coupling Coefficients of Real
Spherical Harmonics and Their Relation to Gaunt Coefficients',
H. H. H. Homeier and E. O. Steinborn J. Mol. Struct., Volume 368,
pp. 31-37 (1996)
Credits and Copyright
=====================
This code was taken from Sage with the permission of all authors:
https://groups.google.com/forum/#!topic/sage-devel/M4NZdu-7O38
Authors
=======
- Jens Rasch (2009-03-24): initial version for Sage
- Jens Rasch (2009-05-31): updated to sage-4.0
- Oscar Gerardo Lazo Arjona (2017-06-18): added Wigner D matrices
- Phil Adam LeMaitre (2022-09-19): added real Gaunt coefficient
Copyright (C) 2008 Jens Rasch <jyr2000@gmail.com>
"""
from sympy.concrete.summations import Sum
from sympy.core.add import Add
from sympy.core.numbers import int_valued
from sympy.core.function import Function
from sympy.core.numbers import (Float, I, Integer, pi, Rational)
from sympy.core.singleton import S
from sympy.core.symbol import Dummy
from sympy.core.sympify import sympify
from sympy.functions.combinatorial.factorials import (binomial, factorial)
from sympy.functions.elementary.complexes import re
from sympy.functions.elementary.exponential import exp
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.elementary.trigonometric import (cos, sin)
from sympy.functions.special.spherical_harmonics import Ynm
from sympy.matrices.dense import zeros
from sympy.matrices.immutable import ImmutableMatrix
from sympy.utilities.misc import as_int
# This list of precomputed factorials is needed to massively
# accelerate future calculations of the various coefficients
_Factlist = [1]
def _calc_factlist(nn):
r"""
Function calculates a list of precomputed factorials in order to
massively accelerate future calculations of the various
coefficients.
Parameters
==========
nn : integer
Highest factorial to be computed.
Returns
=======
list of integers :
The list of precomputed factorials.
Examples
========
Calculate list of factorials::
sage: from sage.functions.wigner import _calc_factlist
sage: _calc_factlist(10)
[1, 1, 2, 6, 24, 120, 720, 5040, 40320, 362880, 3628800]
"""
if nn >= len(_Factlist):
for ii in range(len(_Factlist), int(nn + 1)):
_Factlist.append(_Factlist[ii - 1] * ii)
return _Factlist[:int(nn) + 1]
def _int_or_halfint(value):
"""return Python int unless value is half-int (then return float)"""
if isinstance(value, int):
return value
elif type(value) is float:
if value.is_integer():
return int(value) # an int
if (2*value).is_integer():
return value # a float
elif isinstance(value, Rational):
if value.q == 2:
return value.p/value.q # a float
elif value.q == 1:
return value.p # an int
elif isinstance(value, Float):
return _int_or_halfint(float(value))
raise ValueError("expecting integer or half-integer, got %s" % value)
def wigner_3j(j_1, j_2, j_3, m_1, m_2, m_3):
r"""
Calculate the Wigner 3j symbol `\operatorname{Wigner3j}(j_1,j_2,j_3,m_1,m_2,m_3)`.
Parameters
==========
j_1, j_2, j_3, m_1, m_2, m_3 :
Integer or half integer.
Returns
=======
Rational number times the square root of a rational number.
Examples
========
>>> from sympy.physics.wigner import wigner_3j
>>> wigner_3j(2, 6, 4, 0, 0, 0)
sqrt(715)/143
>>> wigner_3j(2, 6, 4, 0, 0, 1)
0
It is an error to have arguments that are not integer or half
integer values::
sage: wigner_3j(2.1, 6, 4, 0, 0, 0)
Traceback (most recent call last):
...
ValueError: j values must be integer or half integer
sage: wigner_3j(2, 6, 4, 1, 0, -1.1)
Traceback (most recent call last):
...
ValueError: m values must be integer or half integer
Notes
=====
The Wigner 3j symbol obeys the following symmetry rules:
- invariant under any permutation of the columns (with the
exception of a sign change where `J:=j_1+j_2+j_3`):
.. math::
\begin{aligned}
\operatorname{Wigner3j}(j_1,j_2,j_3,m_1,m_2,m_3)
&=\operatorname{Wigner3j}(j_3,j_1,j_2,m_3,m_1,m_2) \\
&=\operatorname{Wigner3j}(j_2,j_3,j_1,m_2,m_3,m_1) \\
&=(-1)^J \operatorname{Wigner3j}(j_3,j_2,j_1,m_3,m_2,m_1) \\
&=(-1)^J \operatorname{Wigner3j}(j_1,j_3,j_2,m_1,m_3,m_2) \\
&=(-1)^J \operatorname{Wigner3j}(j_2,j_1,j_3,m_2,m_1,m_3)
\end{aligned}
- invariant under space inflection, i.e.
.. math::
\operatorname{Wigner3j}(j_1,j_2,j_3,m_1,m_2,m_3)
=(-1)^J \operatorname{Wigner3j}(j_1,j_2,j_3,-m_1,-m_2,-m_3)
- symmetric with respect to the 72 additional symmetries based on
the work by [Regge58]_
- zero for `j_1`, `j_2`, `j_3` not fulfilling triangle relation
- zero for `m_1 + m_2 + m_3 \neq 0`
- zero for violating any one of the conditions
`m_1 \in \{-|j_1|, \ldots, |j_1|\}`,
`m_2 \in \{-|j_2|, \ldots, |j_2|\}`,
`m_3 \in \{-|j_3|, \ldots, |j_3|\}`
Algorithm
=========
This function uses the algorithm of [Edmonds74]_ to calculate the
value of the 3j symbol exactly. Note that the formula contains
alternating sums over large factorials and is therefore unsuitable
for finite precision arithmetic and only useful for a computer
algebra system [Rasch03]_.
Authors
=======
- Jens Rasch (2009-03-24): initial version
"""
j_1, j_2, j_3, m_1, m_2, m_3 = map(_int_or_halfint,
[j_1, j_2, j_3, m_1, m_2, m_3])
if m_1 + m_2 + m_3 != 0:
return S.Zero
a1 = j_1 + j_2 - j_3
if a1 < 0:
return S.Zero
a2 = j_1 - j_2 + j_3
if a2 < 0:
return S.Zero
a3 = -j_1 + j_2 + j_3
if a3 < 0:
return S.Zero
if (abs(m_1) > j_1) or (abs(m_2) > j_2) or (abs(m_3) > j_3):
return S.Zero
if not (int_valued(j_1 - m_1) and \
int_valued(j_2 - m_2) and \
int_valued(j_3 - m_3)):
return S.Zero
maxfact = max(j_1 + j_2 + j_3 + 1, j_1 + abs(m_1), j_2 + abs(m_2),
j_3 + abs(m_3))
_calc_factlist(int(maxfact))
argsqrt = Integer(_Factlist[int(j_1 + j_2 - j_3)] *
_Factlist[int(j_1 - j_2 + j_3)] *
_Factlist[int(-j_1 + j_2 + j_3)] *
_Factlist[int(j_1 - m_1)] *
_Factlist[int(j_1 + m_1)] *
_Factlist[int(j_2 - m_2)] *
_Factlist[int(j_2 + m_2)] *
_Factlist[int(j_3 - m_3)] *
_Factlist[int(j_3 + m_3)]) / \
_Factlist[int(j_1 + j_2 + j_3 + 1)]
ressqrt = sqrt(argsqrt)
if ressqrt.is_complex or ressqrt.is_infinite:
ressqrt = ressqrt.as_real_imag()[0]
imin = max(-j_3 + j_1 + m_2, -j_3 + j_2 - m_1, 0)
imax = min(j_2 + m_2, j_1 - m_1, j_1 + j_2 - j_3)
sumres = 0
for ii in range(int(imin), int(imax) + 1):
den = _Factlist[ii] * \
_Factlist[int(ii + j_3 - j_1 - m_2)] * \
_Factlist[int(j_2 + m_2 - ii)] * \
_Factlist[int(j_1 - ii - m_1)] * \
_Factlist[int(ii + j_3 - j_2 + m_1)] * \
_Factlist[int(j_1 + j_2 - j_3 - ii)]
sumres = sumres + Integer((-1) ** ii) / den
prefid = Integer((-1) ** int(j_1 - j_2 - m_3))
res = ressqrt * sumres * prefid
return res
def clebsch_gordan(j_1, j_2, j_3, m_1, m_2, m_3):
r"""
Calculates the Clebsch-Gordan coefficient.
`\left\langle j_1 m_1 \; j_2 m_2 | j_3 m_3 \right\rangle`.
The reference for this function is [Edmonds74]_.
Parameters
==========
j_1, j_2, j_3, m_1, m_2, m_3 :
Integer or half integer.
Returns
=======
Rational number times the square root of a rational number.
Examples
========
>>> from sympy import S
>>> from sympy.physics.wigner import clebsch_gordan
>>> clebsch_gordan(S(3)/2, S(1)/2, 2, S(3)/2, S(1)/2, 2)
1
>>> clebsch_gordan(S(3)/2, S(1)/2, 1, S(3)/2, -S(1)/2, 1)
sqrt(3)/2
>>> clebsch_gordan(S(3)/2, S(1)/2, 1, -S(1)/2, S(1)/2, 0)
-sqrt(2)/2
Notes
=====
The Clebsch-Gordan coefficient will be evaluated via its relation
to Wigner 3j symbols:
.. math::
\left\langle j_1 m_1 \; j_2 m_2 | j_3 m_3 \right\rangle
=(-1)^{j_1-j_2+m_3} \sqrt{2j_3+1}
\operatorname{Wigner3j}(j_1,j_2,j_3,m_1,m_2,-m_3)
See also the documentation on Wigner 3j symbols which exhibit much
higher symmetry relations than the Clebsch-Gordan coefficient.
Authors
=======
- Jens Rasch (2009-03-24): initial version
"""
j_1 = sympify(j_1)
j_2 = sympify(j_2)
j_3 = sympify(j_3)
m_1 = sympify(m_1)
m_2 = sympify(m_2)
m_3 = sympify(m_3)
w = wigner_3j(j_1, j_2, j_3, m_1, m_2, -m_3)
return (-1) ** (j_1 - j_2 + m_3) * sqrt(2 * j_3 + 1) * w
def _big_delta_coeff(aa, bb, cc, prec=None):
r"""
Calculates the Delta coefficient of the 3 angular momenta for
Racah symbols. Also checks that the differences are of integer
value.
Parameters
==========
aa :
First angular momentum, integer or half integer.
bb :
Second angular momentum, integer or half integer.
cc :
Third angular momentum, integer or half integer.
prec :
Precision of the ``sqrt()`` calculation.
Returns
=======
double : Value of the Delta coefficient.
Examples
========
sage: from sage.functions.wigner import _big_delta_coeff
sage: _big_delta_coeff(1,1,1)
1/2*sqrt(1/6)
"""
# the triangle test will only pass if a) all 3 values are ints or
# b) 1 is an int and the other two are half-ints
if not int_valued(aa + bb - cc):
raise ValueError("j values must be integer or half integer and fulfill the triangle relation")
if not int_valued(aa + cc - bb):
raise ValueError("j values must be integer or half integer and fulfill the triangle relation")
if not int_valued(bb + cc - aa):
raise ValueError("j values must be integer or half integer and fulfill the triangle relation")
if (aa + bb - cc) < 0:
return S.Zero
if (aa + cc - bb) < 0:
return S.Zero
if (bb + cc - aa) < 0:
return S.Zero
maxfact = max(aa + bb - cc, aa + cc - bb, bb + cc - aa, aa + bb + cc + 1)
_calc_factlist(maxfact)
argsqrt = Integer(_Factlist[int(aa + bb - cc)] *
_Factlist[int(aa + cc - bb)] *
_Factlist[int(bb + cc - aa)]) / \
Integer(_Factlist[int(aa + bb + cc + 1)])
ressqrt = sqrt(argsqrt)
if prec:
ressqrt = ressqrt.evalf(prec).as_real_imag()[0]
return ressqrt
def racah(aa, bb, cc, dd, ee, ff, prec=None):
r"""
Calculate the Racah symbol `W(a,b,c,d;e,f)`.
Parameters
==========
a, ..., f :
Integer or half integer.
prec :
Precision, default: ``None``. Providing a precision can
drastically speed up the calculation.
Returns
=======
Rational number times the square root of a rational number
(if ``prec=None``), or real number if a precision is given.
Examples
========
>>> from sympy.physics.wigner import racah
>>> racah(3,3,3,3,3,3)
-1/14
Notes
=====
The Racah symbol is related to the Wigner 6j symbol:
.. math::
\operatorname{Wigner6j}(j_1,j_2,j_3,j_4,j_5,j_6)
=(-1)^{j_1+j_2+j_4+j_5} W(j_1,j_2,j_5,j_4,j_3,j_6)
Please see the 6j symbol for its much richer symmetries and for
additional properties.
Algorithm
=========
This function uses the algorithm of [Edmonds74]_ to calculate the
value of the 6j symbol exactly. Note that the formula contains
alternating sums over large factorials and is therefore unsuitable
for finite precision arithmetic and only useful for a computer
algebra system [Rasch03]_.
Authors
=======
- Jens Rasch (2009-03-24): initial version
"""
prefac = _big_delta_coeff(aa, bb, ee, prec) * \
_big_delta_coeff(cc, dd, ee, prec) * \
_big_delta_coeff(aa, cc, ff, prec) * \
_big_delta_coeff(bb, dd, ff, prec)
if prefac == 0:
return S.Zero
imin = max(aa + bb + ee, cc + dd + ee, aa + cc + ff, bb + dd + ff)
imax = min(aa + bb + cc + dd, aa + dd + ee + ff, bb + cc + ee + ff)
maxfact = max(imax + 1, aa + bb + cc + dd, aa + dd + ee + ff,
bb + cc + ee + ff)
_calc_factlist(maxfact)
sumres = 0
for kk in range(int(imin), int(imax) + 1):
den = _Factlist[int(kk - aa - bb - ee)] * \
_Factlist[int(kk - cc - dd - ee)] * \
_Factlist[int(kk - aa - cc - ff)] * \
_Factlist[int(kk - bb - dd - ff)] * \
_Factlist[int(aa + bb + cc + dd - kk)] * \
_Factlist[int(aa + dd + ee + ff - kk)] * \
_Factlist[int(bb + cc + ee + ff - kk)]
sumres = sumres + Integer((-1) ** kk * _Factlist[kk + 1]) / den
res = prefac * sumres * (-1) ** int(aa + bb + cc + dd)
return res
def wigner_6j(j_1, j_2, j_3, j_4, j_5, j_6, prec=None):
r"""
Calculate the Wigner 6j symbol `\operatorname{Wigner6j}(j_1,j_2,j_3,j_4,j_5,j_6)`.
Parameters
==========
j_1, ..., j_6 :
Integer or half integer.
prec :
Precision, default: ``None``. Providing a precision can
drastically speed up the calculation.
Returns
=======
Rational number times the square root of a rational number
(if ``prec=None``), or real number if a precision is given.
Examples
========
>>> from sympy.physics.wigner import wigner_6j
>>> wigner_6j(3,3,3,3,3,3)
-1/14
>>> wigner_6j(5,5,5,5,5,5)
1/52
It is an error to have arguments that are not integer or half
integer values or do not fulfill the triangle relation::
sage: wigner_6j(2.5,2.5,2.5,2.5,2.5,2.5)
Traceback (most recent call last):
...
ValueError: j values must be integer or half integer and fulfill the triangle relation
sage: wigner_6j(0.5,0.5,1.1,0.5,0.5,1.1)
Traceback (most recent call last):
...
ValueError: j values must be integer or half integer and fulfill the triangle relation
Notes
=====
The Wigner 6j symbol is related to the Racah symbol but exhibits
more symmetries as detailed below.
.. math::
\operatorname{Wigner6j}(j_1,j_2,j_3,j_4,j_5,j_6)
=(-1)^{j_1+j_2+j_4+j_5} W(j_1,j_2,j_5,j_4,j_3,j_6)
The Wigner 6j symbol obeys the following symmetry rules:
- Wigner 6j symbols are left invariant under any permutation of
the columns:
.. math::
\begin{aligned}
\operatorname{Wigner6j}(j_1,j_2,j_3,j_4,j_5,j_6)
&=\operatorname{Wigner6j}(j_3,j_1,j_2,j_6,j_4,j_5) \\
&=\operatorname{Wigner6j}(j_2,j_3,j_1,j_5,j_6,j_4) \\
&=\operatorname{Wigner6j}(j_3,j_2,j_1,j_6,j_5,j_4) \\
&=\operatorname{Wigner6j}(j_1,j_3,j_2,j_4,j_6,j_5) \\
&=\operatorname{Wigner6j}(j_2,j_1,j_3,j_5,j_4,j_6)
\end{aligned}
- They are invariant under the exchange of the upper and lower
arguments in each of any two columns, i.e.
.. math::
\operatorname{Wigner6j}(j_1,j_2,j_3,j_4,j_5,j_6)
=\operatorname{Wigner6j}(j_1,j_5,j_6,j_4,j_2,j_3)
=\operatorname{Wigner6j}(j_4,j_2,j_6,j_1,j_5,j_3)
=\operatorname{Wigner6j}(j_4,j_5,j_3,j_1,j_2,j_6)
- additional 6 symmetries [Regge59]_ giving rise to 144 symmetries
in total
- only non-zero if any triple of `j`'s fulfill a triangle relation
Algorithm
=========
This function uses the algorithm of [Edmonds74]_ to calculate the
value of the 6j symbol exactly. Note that the formula contains
alternating sums over large factorials and is therefore unsuitable
for finite precision arithmetic and only useful for a computer
algebra system [Rasch03]_.
"""
res = (-1) ** int(j_1 + j_2 + j_4 + j_5) * \
racah(j_1, j_2, j_5, j_4, j_3, j_6, prec)
return res
def wigner_9j(j_1, j_2, j_3, j_4, j_5, j_6, j_7, j_8, j_9, prec=None):
r"""
Calculate the Wigner 9j symbol
`\operatorname{Wigner9j}(j_1,j_2,j_3,j_4,j_5,j_6,j_7,j_8,j_9)`.
Parameters
==========
j_1, ..., j_9 :
Integer or half integer.
prec : precision, default
``None``. Providing a precision can
drastically speed up the calculation.
Returns
=======
Rational number times the square root of a rational number
(if ``prec=None``), or real number if a precision is given.
Examples
========
>>> from sympy.physics.wigner import wigner_9j
>>> wigner_9j(1,1,1, 1,1,1, 1,1,0, prec=64)
0.05555555555555555555555555555555555555555555555555555555555555555
>>> wigner_9j(1/2,1/2,0, 1/2,3/2,1, 0,1,1, prec=64)
0.1666666666666666666666666666666666666666666666666666666666666667
It is an error to have arguments that are not integer or half
integer values or do not fulfill the triangle relation::
sage: wigner_9j(0.5,0.5,0.5, 0.5,0.5,0.5, 0.5,0.5,0.5,prec=64)
Traceback (most recent call last):
...
ValueError: j values must be integer or half integer and fulfill the triangle relation
sage: wigner_9j(1,1,1, 0.5,1,1.5, 0.5,1,2.5,prec=64)
Traceback (most recent call last):
...
ValueError: j values must be integer or half integer and fulfill the triangle relation
Algorithm
=========
This function uses the algorithm of [Edmonds74]_ to calculate the
value of the 3j symbol exactly. Note that the formula contains
alternating sums over large factorials and is therefore unsuitable
for finite precision arithmetic and only useful for a computer
algebra system [Rasch03]_.
"""
imax = int(min(j_1 + j_9, j_2 + j_6, j_4 + j_8) * 2)
imin = imax % 2
sumres = 0
for kk in range(imin, int(imax) + 1, 2):
sumres = sumres + (kk + 1) * \
racah(j_1, j_2, j_9, j_6, j_3, kk / 2, prec) * \
racah(j_4, j_6, j_8, j_2, j_5, kk / 2, prec) * \
racah(j_1, j_4, j_9, j_8, j_7, kk / 2, prec)
return sumres
def gaunt(l_1, l_2, l_3, m_1, m_2, m_3, prec=None):
r"""
Calculate the Gaunt coefficient.
Explanation
===========
The Gaunt coefficient is defined as the integral over three
spherical harmonics:
.. math::
\begin{aligned}
\operatorname{Gaunt}(l_1,l_2,l_3,m_1,m_2,m_3)
&=\int Y_{l_1,m_1}(\Omega)
Y_{l_2,m_2}(\Omega) Y_{l_3,m_3}(\Omega) \,d\Omega \\
&=\sqrt{\frac{(2l_1+1)(2l_2+1)(2l_3+1)}{4\pi}}
\operatorname{Wigner3j}(l_1,l_2,l_3,0,0,0)
\operatorname{Wigner3j}(l_1,l_2,l_3,m_1,m_2,m_3)
\end{aligned}
Parameters
==========
l_1, l_2, l_3, m_1, m_2, m_3 :
Integer.
prec - precision, default: ``None``.
Providing a precision can
drastically speed up the calculation.
Returns
=======
Rational number times the square root of a rational number
(if ``prec=None``), or real number if a precision is given.
Examples
========
>>> from sympy.physics.wigner import gaunt
>>> gaunt(1,0,1,1,0,-1)
-1/(2*sqrt(pi))
>>> gaunt(1000,1000,1200,9,3,-12).n(64)
0.006895004219221134484332976156744208248842039317638217822322799675
It is an error to use non-integer values for `l` and `m`::
sage: gaunt(1.2,0,1.2,0,0,0)
Traceback (most recent call last):
...
ValueError: l values must be integer
sage: gaunt(1,0,1,1.1,0,-1.1)
Traceback (most recent call last):
...
ValueError: m values must be integer
Notes
=====
The Gaunt coefficient obeys the following symmetry rules:
- invariant under any permutation of the columns
.. math::
\begin{aligned}
Y(l_1,l_2,l_3,m_1,m_2,m_3)
&=Y(l_3,l_1,l_2,m_3,m_1,m_2) \\
&=Y(l_2,l_3,l_1,m_2,m_3,m_1) \\
&=Y(l_3,l_2,l_1,m_3,m_2,m_1) \\
&=Y(l_1,l_3,l_2,m_1,m_3,m_2) \\
&=Y(l_2,l_1,l_3,m_2,m_1,m_3)
\end{aligned}
- invariant under space inflection, i.e.
.. math::
Y(l_1,l_2,l_3,m_1,m_2,m_3)
=Y(l_1,l_2,l_3,-m_1,-m_2,-m_3)
- symmetric with respect to the 72 Regge symmetries as inherited
for the `3j` symbols [Regge58]_
- zero for `l_1`, `l_2`, `l_3` not fulfilling triangle relation
- zero for violating any one of the conditions: `l_1 \ge |m_1|`,
`l_2 \ge |m_2|`, `l_3 \ge |m_3|`
- non-zero only for an even sum of the `l_i`, i.e.
`L = l_1 + l_2 + l_3 = 2n` for `n` in `\mathbb{N}`
Algorithms
==========
This function uses the algorithm of [Liberatodebrito82]_ to
calculate the value of the Gaunt coefficient exactly. Note that
the formula contains alternating sums over large factorials and is
therefore unsuitable for finite precision arithmetic and only
useful for a computer algebra system [Rasch03]_.
Authors
=======
Jens Rasch (2009-03-24): initial version for Sage.
"""
l_1, l_2, l_3, m_1, m_2, m_3 = [
as_int(i) for i in (l_1, l_2, l_3, m_1, m_2, m_3)]
if l_1 + l_2 - l_3 < 0:
return S.Zero
if l_1 - l_2 + l_3 < 0:
return S.Zero
if -l_1 + l_2 + l_3 < 0:
return S.Zero
if (m_1 + m_2 + m_3) != 0:
return S.Zero
if (abs(m_1) > l_1) or (abs(m_2) > l_2) or (abs(m_3) > l_3):
return S.Zero
bigL, remL = divmod(l_1 + l_2 + l_3, 2)
if remL % 2:
return S.Zero
imin = max(-l_3 + l_1 + m_2, -l_3 + l_2 - m_1, 0)
imax = min(l_2 + m_2, l_1 - m_1, l_1 + l_2 - l_3)
_calc_factlist(max(l_1 + l_2 + l_3 + 1, imax + 1))
ressqrt = sqrt((2 * l_1 + 1) * (2 * l_2 + 1) * (2 * l_3 + 1) * \
_Factlist[l_1 - m_1] * _Factlist[l_1 + m_1] * _Factlist[l_2 - m_2] * \
_Factlist[l_2 + m_2] * _Factlist[l_3 - m_3] * _Factlist[l_3 + m_3] / \
(4*pi))
prefac = Integer(_Factlist[bigL] * _Factlist[l_2 - l_1 + l_3] *
_Factlist[l_1 - l_2 + l_3] * _Factlist[l_1 + l_2 - l_3])/ \
_Factlist[2 * bigL + 1]/ \
(_Factlist[bigL - l_1] *
_Factlist[bigL - l_2] * _Factlist[bigL - l_3])
sumres = 0
for ii in range(int(imin), int(imax) + 1):
den = _Factlist[ii] * _Factlist[ii + l_3 - l_1 - m_2] * \
_Factlist[l_2 + m_2 - ii] * _Factlist[l_1 - ii - m_1] * \
_Factlist[ii + l_3 - l_2 + m_1] * _Factlist[l_1 + l_2 - l_3 - ii]
sumres = sumres + Integer((-1) ** ii) / den
res = ressqrt * prefac * sumres * Integer((-1) ** (bigL + l_3 + m_1 - m_2))
if prec is not None:
res = res.n(prec)
return res
def real_gaunt(l_1, l_2, l_3, m_1, m_2, m_3, prec=None):
r"""
Calculate the real Gaunt coefficient.
Explanation
===========
The real Gaunt coefficient is defined as the integral over three
real spherical harmonics:
.. math::
\begin{aligned}
\operatorname{RealGaunt}(l_1,l_2,l_3,m_1,m_2,m_3)
&=\int Z^{m_1}_{l_1}(\Omega)
Z^{m_2}_{l_2}(\Omega) Z^{m_3}_{l_3}(\Omega) \,d\Omega \\
\end{aligned}
Alternatively, it can be defined in terms of the standard Gaunt
coefficient by relating the real spherical harmonics to the standard
spherical harmonics via a unitary transformation `U`, i.e.
`Z^{m}_{l}(\Omega)=\sum_{m'}U^{m}_{m'}Y^{m'}_{l}(\Omega)` [Homeier96]_.
The real Gaunt coefficient is then defined as
.. math::
\begin{aligned}
\operatorname{RealGaunt}(l_1,l_2,l_3,m_1,m_2,m_3)
&=\int Z^{m_1}_{l_1}(\Omega)
Z^{m_2}_{l_2}(\Omega) Z^{m_3}_{l_3}(\Omega) \,d\Omega \\
&=\sum_{m'_1 m'_2 m'_3} U^{m_1}_{m'_1}U^{m_2}_{m'_2}U^{m_3}_{m'_3}
\operatorname{Gaunt}(l_1,l_2,l_3,m'_1,m'_2,m'_3)
\end{aligned}
The unitary matrix `U` has components
.. math::
\begin{aligned}
U^m_{m'} = \delta_{|m||m'|}*(\delta_{m'0}\delta_{m0} + \frac{1}{\sqrt{2}}\big[\Theta(m)
\big(\delta_{m'm}+(-1)^{m'}\delta_{m'-m}\big)+i\Theta(-m)\big((-1)^{-m}
\delta_{m'-m}-\delta_{m'm}*(-1)^{m'-m}\big)\big])
\end{aligned}
where `\delta_{ij}` is the Kronecker delta symbol and `\Theta` is a step
function defined as
.. math::
\begin{aligned}
\Theta(x) = \begin{cases} 1 \,\text{for}\, x > 0 \\ 0 \,\text{for}\, x \leq 0 \end{cases}
\end{aligned}
Parameters
==========
l_1, l_2, l_3, m_1, m_2, m_3 :
Integer.
prec - precision, default: ``None``.
Providing a precision can
drastically speed up the calculation.
Returns
=======
Rational number times the square root of a rational number.
Examples
========
>>> from sympy.physics.wigner import real_gaunt
>>> real_gaunt(2,2,4,-1,-1,0)
-2/(7*sqrt(pi))
>>> real_gaunt(10,10,20,-9,-9,0).n(64)
-0.00002480019791932209313156167176797577821140084216297395518482071448
It is an error to use non-integer values for `l` and `m`::
real_gaunt(2.8,0.5,1.3,0,0,0)
Traceback (most recent call last):
...
ValueError: l values must be integer
real_gaunt(2,2,4,0.7,1,-3.4)
Traceback (most recent call last):
...
ValueError: m values must be integer
Notes
=====
The real Gaunt coefficient inherits from the standard Gaunt coefficient,
the invariance under any permutation of the pairs `(l_i, m_i)` and the
requirement that the sum of the `l_i` be even to yield a non-zero value.
It also obeys the following symmetry rules:
- zero for `l_1`, `l_2`, `l_3` not fulfiling the condition
`l_1 \in \{l_{\text{max}}, l_{\text{max}}-2, \ldots, l_{\text{min}}\}`,
where `l_{\text{max}} = l_2+l_3`,
.. math::
\begin{aligned}
l_{\text{min}} = \begin{cases} \kappa(l_2, l_3, m_2, m_3) & \text{if}\,
\kappa(l_2, l_3, m_2, m_3) + l_{\text{max}}\, \text{is even} \\
\kappa(l_2, l_3, m_2, m_3)+1 & \text{if}\, \kappa(l_2, l_3, m_2, m_3) +
l_{\text{max}}\, \text{is odd}\end{cases}
\end{aligned}
and `\kappa(l_2, l_3, m_2, m_3) = \max{\big(|l_2-l_3|, \min{\big(|m_2+m_3|,
|m_2-m_3|\big)}\big)}`
- zero for an odd number of negative `m_i`
Algorithms
==========
This function uses the algorithms of [Homeier96]_ and [Rasch03]_ to
calculate the value of the real Gaunt coefficient exactly. Note that
the formula used in [Rasch03]_ contains alternating sums over large
factorials and is therefore unsuitable for finite precision arithmetic
and only useful for a computer algebra system [Rasch03]_. However, this
function can in principle use any algorithm that computes the Gaunt
coefficient, so it is suitable for finite precision arithmetic in so far
as the algorithm which computes the Gaunt coefficient is.
"""
l_1, l_2, l_3, m_1, m_2, m_3 = [
as_int(i) for i in (l_1, l_2, l_3, m_1, m_2, m_3)]
# check for quick exits
if sum(1 for i in (m_1, m_2, m_3) if i < 0) % 2:
return S.Zero # odd number of negative m
if (l_1 + l_2 + l_3) % 2:
return S.Zero # sum of l is odd
lmax = l_2 + l_3
lmin = max(abs(l_2 - l_3), min(abs(m_2 + m_3), abs(m_2 - m_3)))
if (lmin + lmax) % 2:
lmin += 1
if lmin not in range(lmax, lmin - 2, -2):
return S.Zero
kron_del = lambda i, j: 1 if i == j else 0
s = lambda e: -1 if e % 2 else 1 # (-1)**e to give +/-1, avoiding float when e<0
A = lambda a, b: (-kron_del(a, b)*s(a-b) + kron_del(a, -b)*
s(b)) if b < 0 else 0
B = lambda a, b: (kron_del(a, b) + kron_del(a, -b)*s(a)) if b > 0 else 0
C = lambda a, b: kron_del(abs(a), abs(b))*(kron_del(a, 0)*kron_del(b, 0) +
(B(a, b) + I*A(a, b))/sqrt(2))
ugnt = 0
for i in range(-l_1, l_1+1):
U1 = C(i, m_1)
for j in range(-l_2, l_2+1):
U2 = C(j, m_2)
U3 = C(-i-j, m_3)
ugnt = ugnt + re(U1*U2*U3)*gaunt(l_1, l_2, l_3, i, j, -i-j)
if prec is not None:
ugnt = ugnt.n(prec)
return ugnt
class Wigner3j(Function):
def doit(self, **hints):
if all(obj.is_number for obj in self.args):
return wigner_3j(*self.args)
else:
return self
def dot_rot_grad_Ynm(j, p, l, m, theta, phi):
r"""
Returns dot product of rotational gradients of spherical harmonics.
Explanation
===========
This function returns the right hand side of the following expression:
.. math ::
\vec{R}Y{_j^{p}} \cdot \vec{R}Y{_l^{m}} = (-1)^{m+p}
\sum\limits_{k=|l-j|}^{l+j}Y{_k^{m+p}} * \alpha_{l,m,j,p,k} *
\frac{1}{2} (k^2-j^2-l^2+k-j-l)
Arguments
=========
j, p, l, m .... indices in spherical harmonics (expressions or integers)
theta, phi .... angle arguments in spherical harmonics
Example
=======
>>> from sympy import symbols
>>> from sympy.physics.wigner import dot_rot_grad_Ynm
>>> theta, phi = symbols("theta phi")
>>> dot_rot_grad_Ynm(3, 2, 2, 0, theta, phi).doit()
3*sqrt(55)*Ynm(5, 2, theta, phi)/(11*sqrt(pi))
"""
j = sympify(j)
p = sympify(p)
l = sympify(l)
m = sympify(m)
theta = sympify(theta)
phi = sympify(phi)
k = Dummy("k")
def alpha(l,m,j,p,k):
return sqrt((2*l+1)*(2*j+1)*(2*k+1)/(4*pi)) * \
Wigner3j(j, l, k, S.Zero, S.Zero, S.Zero) * \
Wigner3j(j, l, k, p, m, -m-p)
return (S.NegativeOne)**(m+p) * Sum(Ynm(k, m+p, theta, phi) * alpha(l,m,j,p,k) / 2 \
*(k**2-j**2-l**2+k-j-l), (k, abs(l-j), l+j))
def wigner_d_small(J, beta):
"""Return the small Wigner d matrix for angular momentum J.
Explanation
===========
J : An integer, half-integer, or SymPy symbol for the total angular
momentum of the angular momentum space being rotated.
beta : A real number representing the Euler angle of rotation about
the so-called line of nodes. See [Edmonds74]_.
Returns
=======
A matrix representing the corresponding Euler angle rotation( in the basis
of eigenvectors of `J_z`).
.. math ::
\\mathcal{d}_{\\beta} = \\exp\\big( \\frac{i\\beta}{\\hbar} J_y\\big)
The components are calculated using the general form [Edmonds74]_,
equation 4.1.15.
Examples
========
>>> from sympy import Integer, symbols, pi, pprint
>>> from sympy.physics.wigner import wigner_d_small
>>> half = 1/Integer(2)
>>> beta = symbols("beta", real=True)
>>> pprint(wigner_d_small(half, beta), use_unicode=True)
⎡ ⎛β⎞ ⎛β⎞⎤
⎢cos⎜─⎟ sin⎜─⎟⎥
⎢ ⎝2⎠ ⎝2⎠⎥
⎢ ⎥
⎢ ⎛β⎞ ⎛β⎞⎥
⎢-sin⎜─⎟ cos⎜─⎟⎥
⎣ ⎝2⎠ ⎝2⎠⎦
>>> pprint(wigner_d_small(2*half, beta), use_unicode=True)
⎡ 2⎛β⎞ ⎛β⎞ ⎛β⎞ 2⎛β⎞ ⎤
⎢ cos ⎜─⎟ √2⋅sin⎜─⎟⋅cos⎜─⎟ sin ⎜─⎟ ⎥
⎢ ⎝2⎠ ⎝2⎠ ⎝2⎠ ⎝2⎠ ⎥
⎢ ⎥
⎢ ⎛β⎞ ⎛β⎞ 2⎛β⎞ 2⎛β⎞ ⎛β⎞ ⎛β⎞⎥
⎢-√2⋅sin⎜─⎟⋅cos⎜─⎟ - sin ⎜─⎟ + cos ⎜─⎟ √2⋅sin⎜─⎟⋅cos⎜─⎟⎥
⎢ ⎝2⎠ ⎝2⎠ ⎝2⎠ ⎝2⎠ ⎝2⎠ ⎝2⎠⎥
⎢ ⎥
⎢ 2⎛β⎞ ⎛β⎞ ⎛β⎞ 2⎛β⎞ ⎥
⎢ sin ⎜─⎟ -√2⋅sin⎜─⎟⋅cos⎜─⎟ cos ⎜─⎟ ⎥
⎣ ⎝2⎠ ⎝2⎠ ⎝2⎠ ⎝2⎠ ⎦
From table 4 in [Edmonds74]_
>>> pprint(wigner_d_small(half, beta).subs({beta:pi/2}), use_unicode=True)
⎡ √2 √2⎤
⎢ ── ──⎥
⎢ 2 2 ⎥
⎢ ⎥
⎢-√2 √2⎥
⎢──── ──⎥
⎣ 2 2 ⎦
>>> pprint(wigner_d_small(2*half, beta).subs({beta:pi/2}),
... use_unicode=True)
⎡ √2 ⎤
⎢1/2 ── 1/2⎥
⎢ 2 ⎥
⎢ ⎥
⎢-√2 √2 ⎥
⎢──── 0 ── ⎥
⎢ 2 2 ⎥
⎢ ⎥
⎢ -√2 ⎥
⎢1/2 ──── 1/2⎥
⎣ 2 ⎦
>>> pprint(wigner_d_small(3*half, beta).subs({beta:pi/2}),
... use_unicode=True)
⎡ √2 √6 √6 √2⎤
⎢ ── ── ── ──⎥
⎢ 4 4 4 4 ⎥
⎢ ⎥
⎢-√6 -√2 √2 √6⎥
⎢──── ──── ── ──⎥
⎢ 4 4 4 4 ⎥
⎢ ⎥
⎢ √6 -√2 -√2 √6⎥
⎢ ── ──── ──── ──⎥
⎢ 4 4 4 4 ⎥
⎢ ⎥
⎢-√2 √6 -√6 √2⎥
⎢──── ── ──── ──⎥
⎣ 4 4 4 4 ⎦
>>> pprint(wigner_d_small(4*half, beta).subs({beta:pi/2}),
... use_unicode=True)
⎡ √6 ⎤
⎢1/4 1/2 ── 1/2 1/4⎥
⎢ 4 ⎥
⎢ ⎥
⎢-1/2 -1/2 0 1/2 1/2⎥
⎢ ⎥
⎢ √6 √6 ⎥
⎢ ── 0 -1/2 0 ── ⎥
⎢ 4 4 ⎥
⎢ ⎥
⎢-1/2 1/2 0 -1/2 1/2⎥
⎢ ⎥
⎢ √6 ⎥
⎢1/4 -1/2 ── -1/2 1/4⎥
⎣ 4 ⎦
"""
M = [J-i for i in range(2*J+1)]
d = zeros(2*J+1)
for i, Mi in enumerate(M):
for j, Mj in enumerate(M):
# We get the maximum and minimum value of sigma.
sigmamax = min([J-Mi, J-Mj])
sigmamin = max([0, -Mi-Mj])
dij = sqrt(factorial(J+Mi)*factorial(J-Mi) /
factorial(J+Mj)/factorial(J-Mj))
terms = [(-1)**(J-Mi-s) *
binomial(J+Mj, J-Mi-s) *
binomial(J-Mj, s) *
cos(beta/2)**(2*s+Mi+Mj) *
sin(beta/2)**(2*J-2*s-Mj-Mi)
for s in range(sigmamin, sigmamax+1)]
d[i, j] = dij*Add(*terms)
return ImmutableMatrix(d)
def wigner_d(J, alpha, beta, gamma):
"""Return the Wigner D matrix for angular momentum J.
Explanation
===========
J :
An integer, half-integer, or SymPy symbol for the total angular
momentum of the angular momentum space being rotated.
alpha, beta, gamma - Real numbers representing the Euler.
Angles of rotation about the so-called vertical, line of nodes, and
figure axes. See [Edmonds74]_.
Returns
=======
A matrix representing the corresponding Euler angle rotation( in the basis
of eigenvectors of `J_z`).
.. math ::
\\mathcal{D}_{\\alpha \\beta \\gamma} =
\\exp\\big( \\frac{i\\alpha}{\\hbar} J_z\\big)
\\exp\\big( \\frac{i\\beta}{\\hbar} J_y\\big)
\\exp\\big( \\frac{i\\gamma}{\\hbar} J_z\\big)
The components are calculated using the general form [Edmonds74]_,
equation 4.1.12.
Examples
========
The simplest possible example:
>>> from sympy.physics.wigner import wigner_d
>>> from sympy import Integer, symbols, pprint
>>> half = 1/Integer(2)
>>> alpha, beta, gamma = symbols("alpha, beta, gamma", real=True)
>>> pprint(wigner_d(half, alpha, beta, gamma), use_unicode=True)
⎡ ⅈ⋅α ⅈ⋅γ ⅈ⋅α -ⅈ⋅γ ⎤
⎢ ─── ─── ─── ───── ⎥
⎢ 2 2 ⎛β⎞ 2 2 ⎛β⎞ ⎥
⎢ ℯ ⋅ℯ ⋅cos⎜─⎟ ℯ ⋅ℯ ⋅sin⎜─⎟ ⎥
⎢ ⎝2⎠ ⎝2⎠ ⎥
⎢ ⎥
⎢ -ⅈ⋅α ⅈ⋅γ -ⅈ⋅α -ⅈ⋅γ ⎥
⎢ ───── ─── ───── ───── ⎥
⎢ 2 2 ⎛β⎞ 2 2 ⎛β⎞⎥
⎢-ℯ ⋅ℯ ⋅sin⎜─⎟ ℯ ⋅ℯ ⋅cos⎜─⎟⎥
⎣ ⎝2⎠ ⎝2⎠⎦
"""
d = wigner_d_small(J, beta)
M = [J-i for i in range(2*J+1)]
D = [[exp(I*Mi*alpha)*d[i, j]*exp(I*Mj*gamma)
for j, Mj in enumerate(M)] for i, Mi in enumerate(M)]
return ImmutableMatrix(D)
PK ]ZZZ\i� � & sympy/physics/biomechanics/__init__.py"""Biomechanics extension for SymPy.
Includes biomechanics-related constructs which allows users to extend multibody
models created using `sympy.physics.mechanics` into biomechanical or
musculoskeletal models involding musculotendons and activation dynamics.
"""
from .activation import (
ActivationBase,
FirstOrderActivationDeGroote2016,
ZerothOrderActivation,
)
from .curve import (
CharacteristicCurveCollection,
CharacteristicCurveFunction,
FiberForceLengthActiveDeGroote2016,
FiberForceLengthPassiveDeGroote2016,
FiberForceLengthPassiveInverseDeGroote2016,
FiberForceVelocityDeGroote2016,
FiberForceVelocityInverseDeGroote2016,
TendonForceLengthDeGroote2016,
TendonForceLengthInverseDeGroote2016,
)
from .musculotendon import (
MusculotendonBase,
MusculotendonDeGroote2016,
MusculotendonFormulation,
)
__all__ = [
# Musculotendon characteristic curve functions
'CharacteristicCurveCollection',
'CharacteristicCurveFunction',
'FiberForceLengthActiveDeGroote2016',
'FiberForceLengthPassiveDeGroote2016',
'FiberForceLengthPassiveInverseDeGroote2016',
'FiberForceVelocityDeGroote2016',
'FiberForceVelocityInverseDeGroote2016',
'TendonForceLengthDeGroote2016',
'TendonForceLengthInverseDeGroote2016',
# Activation dynamics classes
'ActivationBase',
'FirstOrderActivationDeGroote2016',
'ZerothOrderActivation',
# Musculotendon classes
'MusculotendonBase',
'MusculotendonDeGroote2016',
'MusculotendonFormulation',
]
PK ]ZZZ3�}� � $ sympy/physics/biomechanics/_mixin.py"""Mixin classes for sharing functionality between unrelated classes.
This module is named with a leading underscore to signify to users that it's
"private" and only intended for internal use by the biomechanics module.
"""
__all__ = ['_NamedMixin']
class _NamedMixin:
"""Mixin class for adding `name` properties.
Valid names, as will typically be used by subclasses as a suffix when
naming automatically-instantiated symbol attributes, must be nonzero length
strings.
Attributes
==========
name : str
The name identifier associated with the instance. Must be a string of
length at least 1.
"""
@property
def name(self) -> str:
"""The name associated with the class instance."""
return self._name
@name.setter
def name(self, name: str) -> None:
if hasattr(self, '_name'):
msg = (
f'Can\'t set attribute `name` to {repr(name)} as it is '
f'immutable.'
)
raise AttributeError(msg)
if not isinstance(name, str):
msg = (
f'Name {repr(name)} passed to `name` was of type '
f'{type(name)}, must be {str}.'
)
raise TypeError(msg)
if name in {''}:
msg = (
f'Name {repr(name)} is invalid, must be a nonzero length '
f'{type(str)}.'
)
raise ValueError(msg)
self._name = name
PK ]ZZZ5�E�c �c ( sympy/physics/biomechanics/activation.pyr"""Activation dynamics for musclotendon models.
Musculotendon models are able to produce active force when they are activated,
which is when a chemical process has taken place within the muscle fibers
causing them to voluntarily contract. Biologically this chemical process (the
diffusion of :math:`\textrm{Ca}^{2+}` ions) is not the input in the system,
electrical signals from the nervous system are. These are termed excitations.
Activation dynamics, which relates the normalized excitation level to the
normalized activation level, can be modeled by the models present in this
module.
"""
from abc import ABC, abstractmethod
from functools import cached_property
from sympy.core.symbol import Symbol
from sympy.core.numbers import Float, Integer, Rational
from sympy.functions.elementary.hyperbolic import tanh
from sympy.matrices.dense import MutableDenseMatrix as Matrix, zeros
from sympy.physics.biomechanics._mixin import _NamedMixin
from sympy.physics.mechanics import dynamicsymbols
__all__ = [
'ActivationBase',
'FirstOrderActivationDeGroote2016',
'ZerothOrderActivation',
]
class ActivationBase(ABC, _NamedMixin):
"""Abstract base class for all activation dynamics classes to inherit from.
Notes
=====
Instances of this class cannot be directly instantiated by users. However,
it can be used to created custom activation dynamics types through
subclassing.
"""
def __init__(self, name):
"""Initializer for ``ActivationBase``."""
self.name = str(name)
# Symbols
self._e = dynamicsymbols(f"e_{name}")
self._a = dynamicsymbols(f"a_{name}")
@classmethod
@abstractmethod
def with_defaults(cls, name):
"""Alternate constructor that provides recommended defaults for
constants."""
pass
@property
def excitation(self):
"""Dynamic symbol representing excitation.
Explanation
===========
The alias ``e`` can also be used to access the same attribute.
"""
return self._e
@property
def e(self):
"""Dynamic symbol representing excitation.
Explanation
===========
The alias ``excitation`` can also be used to access the same attribute.
"""
return self._e
@property
def activation(self):
"""Dynamic symbol representing activation.
Explanation
===========
The alias ``a`` can also be used to access the same attribute.
"""
return self._a
@property
def a(self):
"""Dynamic symbol representing activation.
Explanation
===========
The alias ``activation`` can also be used to access the same attribute.
"""
return self._a
@property
@abstractmethod
def order(self):
"""Order of the (differential) equation governing activation."""
pass
@property
@abstractmethod
def state_vars(self):
"""Ordered column matrix of functions of time that represent the state
variables.
Explanation
===========
The alias ``x`` can also be used to access the same attribute.
"""
pass
@property
@abstractmethod
def x(self):
"""Ordered column matrix of functions of time that represent the state
variables.
Explanation
===========
The alias ``state_vars`` can also be used to access the same attribute.
"""
pass
@property
@abstractmethod
def input_vars(self):
"""Ordered column matrix of functions of time that represent the input
variables.
Explanation
===========
The alias ``r`` can also be used to access the same attribute.
"""
pass
@property
@abstractmethod
def r(self):
"""Ordered column matrix of functions of time that represent the input
variables.
Explanation
===========
The alias ``input_vars`` can also be used to access the same attribute.
"""
pass
@property
@abstractmethod
def constants(self):
"""Ordered column matrix of non-time varying symbols present in ``M``
and ``F``.
Only symbolic constants are returned. If a numeric type (e.g. ``Float``)
has been used instead of ``Symbol`` for a constant then that attribute
will not be included in the matrix returned by this property. This is
because the primary use of this property attribute is to provide an
ordered sequence of the still-free symbols that require numeric values
during code generation.
Explanation
===========
The alias ``p`` can also be used to access the same attribute.
"""
pass
@property
@abstractmethod
def p(self):
"""Ordered column matrix of non-time varying symbols present in ``M``
and ``F``.
Only symbolic constants are returned. If a numeric type (e.g. ``Float``)
has been used instead of ``Symbol`` for a constant then that attribute
will not be included in the matrix returned by this property. This is
because the primary use of this property attribute is to provide an
ordered sequence of the still-free symbols that require numeric values
during code generation.
Explanation
===========
The alias ``constants`` can also be used to access the same attribute.
"""
pass
@property
@abstractmethod
def M(self):
"""Ordered square matrix of coefficients on the LHS of ``M x' = F``.
Explanation
===========
The square matrix that forms part of the LHS of the linear system of
ordinary differential equations governing the activation dynamics:
``M(x, r, t, p) x' = F(x, r, t, p)``.
"""
pass
@property
@abstractmethod
def F(self):
"""Ordered column matrix of equations on the RHS of ``M x' = F``.
Explanation
===========
The column matrix that forms the RHS of the linear system of ordinary
differential equations governing the activation dynamics:
``M(x, r, t, p) x' = F(x, r, t, p)``.
"""
pass
@abstractmethod
def rhs(self):
"""
Explanation
===========
The solution to the linear system of ordinary differential equations
governing the activation dynamics:
``M(x, r, t, p) x' = F(x, r, t, p)``.
"""
pass
def __eq__(self, other):
"""Equality check for activation dynamics."""
if type(self) != type(other):
return False
if self.name != other.name:
return False
return True
def __repr__(self):
"""Default representation of activation dynamics."""
return f'{self.__class__.__name__}({self.name!r})'
class ZerothOrderActivation(ActivationBase):
"""Simple zeroth-order activation dynamics mapping excitation to
activation.
Explanation
===========
Zeroth-order activation dynamics are useful in instances where you want to
reduce the complexity of your musculotendon dynamics as they simple map
exictation to activation. As a result, no additional state equations are
introduced to your system. They also remove a potential source of delay
between the input and dynamics of your system as no (ordinary) differential
equations are involed.
"""
def __init__(self, name):
"""Initializer for ``ZerothOrderActivation``.
Parameters
==========
name : str
The name identifier associated with the instance. Must be a string
of length at least 1.
"""
super().__init__(name)
# Zeroth-order activation dynamics has activation equal excitation so
# overwrite the symbol for activation with the excitation symbol.
self._a = self._e
@classmethod
def with_defaults(cls, name):
"""Alternate constructor that provides recommended defaults for
constants.
Explanation
===========
As this concrete class doesn't implement any constants associated with
its dynamics, this ``classmethod`` simply creates a standard instance
of ``ZerothOrderActivation``. An implementation is provided to ensure
a consistent interface between all ``ActivationBase`` concrete classes.
"""
return cls(name)
@property
def order(self):
"""Order of the (differential) equation governing activation."""
return 0
@property
def state_vars(self):
"""Ordered column matrix of functions of time that represent the state
variables.
Explanation
===========
As zeroth-order activation dynamics simply maps excitation to
activation, this class has no associated state variables and so this
property return an empty column ``Matrix`` with shape (0, 1).
The alias ``x`` can also be used to access the same attribute.
"""
return zeros(0, 1)
@property
def x(self):
"""Ordered column matrix of functions of time that represent the state
variables.
Explanation
===========
As zeroth-order activation dynamics simply maps excitation to
activation, this class has no associated state variables and so this
property return an empty column ``Matrix`` with shape (0, 1).
The alias ``state_vars`` can also be used to access the same attribute.
"""
return zeros(0, 1)
@property
def input_vars(self):
"""Ordered column matrix of functions of time that represent the input
variables.
Explanation
===========
Excitation is the only input in zeroth-order activation dynamics and so
this property returns a column ``Matrix`` with one entry, ``e``, and
shape (1, 1).
The alias ``r`` can also be used to access the same attribute.
"""
return Matrix([self._e])
@property
def r(self):
"""Ordered column matrix of functions of time that represent the input
variables.
Explanation
===========
Excitation is the only input in zeroth-order activation dynamics and so
this property returns a column ``Matrix`` with one entry, ``e``, and
shape (1, 1).
The alias ``input_vars`` can also be used to access the same attribute.
"""
return Matrix([self._e])
@property
def constants(self):
"""Ordered column matrix of non-time varying symbols present in ``M``
and ``F``.
Only symbolic constants are returned. If a numeric type (e.g. ``Float``)
has been used instead of ``Symbol`` for a constant then that attribute
will not be included in the matrix returned by this property. This is
because the primary use of this property attribute is to provide an
ordered sequence of the still-free symbols that require numeric values
during code generation.
Explanation
===========
As zeroth-order activation dynamics simply maps excitation to
activation, this class has no associated constants and so this property
return an empty column ``Matrix`` with shape (0, 1).
The alias ``p`` can also be used to access the same attribute.
"""
return zeros(0, 1)
@property
def p(self):
"""Ordered column matrix of non-time varying symbols present in ``M``
and ``F``.
Only symbolic constants are returned. If a numeric type (e.g. ``Float``)
has been used instead of ``Symbol`` for a constant then that attribute
will not be included in the matrix returned by this property. This is
because the primary use of this property attribute is to provide an
ordered sequence of the still-free symbols that require numeric values
during code generation.
Explanation
===========
As zeroth-order activation dynamics simply maps excitation to
activation, this class has no associated constants and so this property
return an empty column ``Matrix`` with shape (0, 1).
The alias ``constants`` can also be used to access the same attribute.
"""
return zeros(0, 1)
@property
def M(self):
"""Ordered square matrix of coefficients on the LHS of ``M x' = F``.
Explanation
===========
The square matrix that forms part of the LHS of the linear system of
ordinary differential equations governing the activation dynamics:
``M(x, r, t, p) x' = F(x, r, t, p)``.
As zeroth-order activation dynamics have no state variables, this
linear system has dimension 0 and therefore ``M`` is an empty square
``Matrix`` with shape (0, 0).
"""
return Matrix([])
@property
def F(self):
"""Ordered column matrix of equations on the RHS of ``M x' = F``.
Explanation
===========
The column matrix that forms the RHS of the linear system of ordinary
differential equations governing the activation dynamics:
``M(x, r, t, p) x' = F(x, r, t, p)``.
As zeroth-order activation dynamics have no state variables, this
linear system has dimension 0 and therefore ``F`` is an empty column
``Matrix`` with shape (0, 1).
"""
return zeros(0, 1)
def rhs(self):
"""Ordered column matrix of equations for the solution of ``M x' = F``.
Explanation
===========
The solution to the linear system of ordinary differential equations
governing the activation dynamics:
``M(x, r, t, p) x' = F(x, r, t, p)``.
As zeroth-order activation dynamics have no state variables, this
linear has dimension 0 and therefore this method returns an empty
column ``Matrix`` with shape (0, 1).
"""
return zeros(0, 1)
class FirstOrderActivationDeGroote2016(ActivationBase):
r"""First-order activation dynamics based on De Groote et al., 2016 [1]_.
Explanation
===========
Gives the first-order activation dynamics equation for the rate of change
of activation with respect to time as a function of excitation and
activation.
The function is defined by the equation:
.. math::
\frac{da}{dt} = \left(\frac{\frac{1}{2} + a0}{\tau_a \left(\frac{1}{2}
+ \frac{3a}{2}\right)} + \frac{\left(\frac{1}{2}
+ \frac{3a}{2}\right) \left(\frac{1}{2} - a0\right)}{\tau_d}\right)
\left(e - a\right)
where
.. math::
a0 = \frac{\tanh{\left(b \left(e - a\right) \right)}}{2}
with constant values of :math:`tau_a = 0.015`, :math:`tau_d = 0.060`, and
:math:`b = 10`.
References
==========
.. [1] De Groote, F., Kinney, A. L., Rao, A. V., & Fregly, B. J., Evaluation
of direct collocation optimal control problem formulations for
solving the muscle redundancy problem, Annals of biomedical
engineering, 44(10), (2016) pp. 2922-2936
"""
def __init__(self,
name,
activation_time_constant=None,
deactivation_time_constant=None,
smoothing_rate=None,
):
"""Initializer for ``FirstOrderActivationDeGroote2016``.
Parameters
==========
activation time constant : Symbol | Number | None
The value of the activation time constant governing the delay
between excitation and activation when excitation exceeds
activation.
deactivation time constant : Symbol | Number | None
The value of the deactivation time constant governing the delay
between excitation and activation when activation exceeds
excitation.
smoothing_rate : Symbol | Number | None
The slope of the hyperbolic tangent function used to smooth between
the switching of the equations where excitation exceed activation
and where activation exceeds excitation. The recommended value to
use is ``10``, but values between ``0.1`` and ``100`` can be used.
"""
super().__init__(name)
# Symbols
self.activation_time_constant = activation_time_constant
self.deactivation_time_constant = deactivation_time_constant
self.smoothing_rate = smoothing_rate
@classmethod
def with_defaults(cls, name):
r"""Alternate constructor that will use the published constants.
Explanation
===========
Returns an instance of ``FirstOrderActivationDeGroote2016`` using the
three constant values specified in the original publication.
These have the values:
:math:`tau_a = 0.015`
:math:`tau_d = 0.060`
:math:`b = 10`
"""
tau_a = Float('0.015')
tau_d = Float('0.060')
b = Float('10.0')
return cls(name, tau_a, tau_d, b)
@property
def activation_time_constant(self):
"""Delay constant for activation.
Explanation
===========
The alias ```tau_a`` can also be used to access the same attribute.
"""
return self._tau_a
@activation_time_constant.setter
def activation_time_constant(self, tau_a):
if hasattr(self, '_tau_a'):
msg = (
f'Can\'t set attribute `activation_time_constant` to '
f'{repr(tau_a)} as it is immutable and already has value '
f'{self._tau_a}.'
)
raise AttributeError(msg)
self._tau_a = Symbol(f'tau_a_{self.name}') if tau_a is None else tau_a
@property
def tau_a(self):
"""Delay constant for activation.
Explanation
===========
The alias ``activation_time_constant`` can also be used to access the
same attribute.
"""
return self._tau_a
@property
def deactivation_time_constant(self):
"""Delay constant for deactivation.
Explanation
===========
The alias ``tau_d`` can also be used to access the same attribute.
"""
return self._tau_d
@deactivation_time_constant.setter
def deactivation_time_constant(self, tau_d):
if hasattr(self, '_tau_d'):
msg = (
f'Can\'t set attribute `deactivation_time_constant` to '
f'{repr(tau_d)} as it is immutable and already has value '
f'{self._tau_d}.'
)
raise AttributeError(msg)
self._tau_d = Symbol(f'tau_d_{self.name}') if tau_d is None else tau_d
@property
def tau_d(self):
"""Delay constant for deactivation.
Explanation
===========
The alias ``deactivation_time_constant`` can also be used to access the
same attribute.
"""
return self._tau_d
@property
def smoothing_rate(self):
"""Smoothing constant for the hyperbolic tangent term.
Explanation
===========
The alias ``b`` can also be used to access the same attribute.
"""
return self._b
@smoothing_rate.setter
def smoothing_rate(self, b):
if hasattr(self, '_b'):
msg = (
f'Can\'t set attribute `smoothing_rate` to {b!r} as it is '
f'immutable and already has value {self._b!r}.'
)
raise AttributeError(msg)
self._b = Symbol(f'b_{self.name}') if b is None else b
@property
def b(self):
"""Smoothing constant for the hyperbolic tangent term.
Explanation
===========
The alias ``smoothing_rate`` can also be used to access the same
attribute.
"""
return self._b
@property
def order(self):
"""Order of the (differential) equation governing activation."""
return 1
@property
def state_vars(self):
"""Ordered column matrix of functions of time that represent the state
variables.
Explanation
===========
The alias ``x`` can also be used to access the same attribute.
"""
return Matrix([self._a])
@property
def x(self):
"""Ordered column matrix of functions of time that represent the state
variables.
Explanation
===========
The alias ``state_vars`` can also be used to access the same attribute.
"""
return Matrix([self._a])
@property
def input_vars(self):
"""Ordered column matrix of functions of time that represent the input
variables.
Explanation
===========
The alias ``r`` can also be used to access the same attribute.
"""
return Matrix([self._e])
@property
def r(self):
"""Ordered column matrix of functions of time that represent the input
variables.
Explanation
===========
The alias ``input_vars`` can also be used to access the same attribute.
"""
return Matrix([self._e])
@property
def constants(self):
"""Ordered column matrix of non-time varying symbols present in ``M``
and ``F``.
Only symbolic constants are returned. If a numeric type (e.g. ``Float``)
has been used instead of ``Symbol`` for a constant then that attribute
will not be included in the matrix returned by this property. This is
because the primary use of this property attribute is to provide an
ordered sequence of the still-free symbols that require numeric values
during code generation.
Explanation
===========
The alias ``p`` can also be used to access the same attribute.
"""
constants = [self._tau_a, self._tau_d, self._b]
symbolic_constants = [c for c in constants if not c.is_number]
return Matrix(symbolic_constants) if symbolic_constants else zeros(0, 1)
@property
def p(self):
"""Ordered column matrix of non-time varying symbols present in ``M``
and ``F``.
Explanation
===========
Only symbolic constants are returned. If a numeric type (e.g. ``Float``)
has been used instead of ``Symbol`` for a constant then that attribute
will not be included in the matrix returned by this property. This is
because the primary use of this property attribute is to provide an
ordered sequence of the still-free symbols that require numeric values
during code generation.
The alias ``constants`` can also be used to access the same attribute.
"""
constants = [self._tau_a, self._tau_d, self._b]
symbolic_constants = [c for c in constants if not c.is_number]
return Matrix(symbolic_constants) if symbolic_constants else zeros(0, 1)
@property
def M(self):
"""Ordered square matrix of coefficients on the LHS of ``M x' = F``.
Explanation
===========
The square matrix that forms part of the LHS of the linear system of
ordinary differential equations governing the activation dynamics:
``M(x, r, t, p) x' = F(x, r, t, p)``.
"""
return Matrix([Integer(1)])
@property
def F(self):
"""Ordered column matrix of equations on the RHS of ``M x' = F``.
Explanation
===========
The column matrix that forms the RHS of the linear system of ordinary
differential equations governing the activation dynamics:
``M(x, r, t, p) x' = F(x, r, t, p)``.
"""
return Matrix([self._da_eqn])
def rhs(self):
"""Ordered column matrix of equations for the solution of ``M x' = F``.
Explanation
===========
The solution to the linear system of ordinary differential equations
governing the activation dynamics:
``M(x, r, t, p) x' = F(x, r, t, p)``.
"""
return Matrix([self._da_eqn])
@cached_property
def _da_eqn(self):
HALF = Rational(1, 2)
a0 = HALF * tanh(self._b * (self._e - self._a))
a1 = (HALF + Rational(3, 2) * self._a)
a2 = (HALF + a0) / (self._tau_a * a1)
a3 = a1 * (HALF - a0) / self._tau_d
activation_dynamics_equation = (a2 + a3) * (self._e - self._a)
return activation_dynamics_equation
def __eq__(self, other):
"""Equality check for ``FirstOrderActivationDeGroote2016``."""
if type(self) != type(other):
return False
self_attrs = (self.name, self.tau_a, self.tau_d, self.b)
other_attrs = (other.name, other.tau_a, other.tau_d, other.b)
if self_attrs == other_attrs:
return True
return False
def __repr__(self):
"""Representation of ``FirstOrderActivationDeGroote2016``."""
return (
f'{self.__class__.__name__}({self.name!r}, '
f'activation_time_constant={self.tau_a!r}, '
f'deactivation_time_constant={self.tau_d!r}, '
f'smoothing_rate={self.b!r})'
)
PK ]ZZZ���t � � # sympy/physics/biomechanics/curve.py"""Implementations of characteristic curves for musculotendon models."""
from dataclasses import dataclass
from sympy.core.expr import UnevaluatedExpr
from sympy.core.function import ArgumentIndexError, Function
from sympy.core.numbers import Float, Integer
from sympy.functions.elementary.exponential import exp, log
from sympy.functions.elementary.hyperbolic import cosh, sinh
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.printing.precedence import PRECEDENCE
__all__ = [
'CharacteristicCurveCollection',
'CharacteristicCurveFunction',
'FiberForceLengthActiveDeGroote2016',
'FiberForceLengthPassiveDeGroote2016',
'FiberForceLengthPassiveInverseDeGroote2016',
'FiberForceVelocityDeGroote2016',
'FiberForceVelocityInverseDeGroote2016',
'TendonForceLengthDeGroote2016',
'TendonForceLengthInverseDeGroote2016',
]
class CharacteristicCurveFunction(Function):
"""Base class for all musculotendon characteristic curve functions."""
@classmethod
def eval(cls):
msg = (
f'Cannot directly instantiate {cls.__name__!r}, instances of '
f'characteristic curves must be of a concrete subclass.'
)
raise TypeError(msg)
def _print_code(self, printer):
"""Print code for the function defining the curve using a printer.
Explanation
===========
The order of operations may need to be controlled as constant folding
the numeric terms within the equations of a musculotendon
characteristic curve can sometimes results in a numerically-unstable
expression.
Parameters
==========
printer : Printer
The printer to be used to print a string representation of the
characteristic curve as valid code in the target language.
"""
return printer._print(printer.parenthesize(
self.doit(deep=False, evaluate=False), PRECEDENCE['Atom'],
))
_ccode = _print_code
_cupycode = _print_code
_cxxcode = _print_code
_fcode = _print_code
_jaxcode = _print_code
_lambdacode = _print_code
_mpmathcode = _print_code
_octave = _print_code
_pythoncode = _print_code
_numpycode = _print_code
_scipycode = _print_code
class TendonForceLengthDeGroote2016(CharacteristicCurveFunction):
r"""Tendon force-length curve based on De Groote et al., 2016 [1]_.
Explanation
===========
Gives the normalized tendon force produced as a function of normalized
tendon length.
The function is defined by the equation:
$fl^T = c_0 \exp{c_3 \left( \tilde{l}^T - c_1 \right)} - c_2$
with constant values of $c_0 = 0.2$, $c_1 = 0.995$, $c_2 = 0.25$, and
$c_3 = 33.93669377311689$.
While it is possible to change the constant values, these were carefully
selected in the original publication to give the characteristic curve
specific and required properties. For example, the function produces no
force when the tendon is in an unstrained state. It also produces a force
of 1 normalized unit when the tendon is under a 5% strain.
Examples
========
The preferred way to instantiate :class:`TendonForceLengthDeGroote2016` is using
the :meth:`~.with_defaults` constructor because this will automatically
populate the constants within the characteristic curve equation with the
floating point values from the original publication. This constructor takes
a single argument corresponding to normalized tendon length. We'll create a
:class:`~.Symbol` called ``l_T_tilde`` to represent this.
>>> from sympy import Symbol
>>> from sympy.physics.biomechanics import TendonForceLengthDeGroote2016
>>> l_T_tilde = Symbol('l_T_tilde')
>>> fl_T = TendonForceLengthDeGroote2016.with_defaults(l_T_tilde)
>>> fl_T
TendonForceLengthDeGroote2016(l_T_tilde, 0.2, 0.995, 0.25,
33.93669377311689)
It's also possible to populate the four constants with your own values too.
>>> from sympy import symbols
>>> c0, c1, c2, c3 = symbols('c0 c1 c2 c3')
>>> fl_T = TendonForceLengthDeGroote2016(l_T_tilde, c0, c1, c2, c3)
>>> fl_T
TendonForceLengthDeGroote2016(l_T_tilde, c0, c1, c2, c3)
You don't just have to use symbols as the arguments, it's also possible to
use expressions. Let's create a new pair of symbols, ``l_T`` and
``l_T_slack``, representing tendon length and tendon slack length
respectively. We can then represent ``l_T_tilde`` as an expression, the
ratio of these.
>>> l_T, l_T_slack = symbols('l_T l_T_slack')
>>> l_T_tilde = l_T/l_T_slack
>>> fl_T = TendonForceLengthDeGroote2016.with_defaults(l_T_tilde)
>>> fl_T
TendonForceLengthDeGroote2016(l_T/l_T_slack, 0.2, 0.995, 0.25,
33.93669377311689)
To inspect the actual symbolic expression that this function represents,
we can call the :meth:`~.doit` method on an instance. We'll use the keyword
argument ``evaluate=False`` as this will keep the expression in its
canonical form and won't simplify any constants.
>>> fl_T.doit(evaluate=False)
-0.25 + 0.2*exp(33.93669377311689*(l_T/l_T_slack - 0.995))
The function can also be differentiated. We'll differentiate with respect
to l_T using the ``diff`` method on an instance with the single positional
argument ``l_T``.
>>> fl_T.diff(l_T)
6.787338754623378*exp(33.93669377311689*(l_T/l_T_slack - 0.995))/l_T_slack
References
==========
.. [1] De Groote, F., Kinney, A. L., Rao, A. V., & Fregly, B. J., Evaluation
of direct collocation optimal control problem formulations for
solving the muscle redundancy problem, Annals of biomedical
engineering, 44(10), (2016) pp. 2922-2936
"""
@classmethod
def with_defaults(cls, l_T_tilde):
r"""Recommended constructor that will use the published constants.
Explanation
===========
Returns a new instance of the tendon force-length function using the
four constant values specified in the original publication.
These have the values:
$c_0 = 0.2$
$c_1 = 0.995$
$c_2 = 0.25$
$c_3 = 33.93669377311689$
Parameters
==========
l_T_tilde : Any (sympifiable)
Normalized tendon length.
"""
c0 = Float('0.2')
c1 = Float('0.995')
c2 = Float('0.25')
c3 = Float('33.93669377311689')
return cls(l_T_tilde, c0, c1, c2, c3)
@classmethod
def eval(cls, l_T_tilde, c0, c1, c2, c3):
"""Evaluation of basic inputs.
Parameters
==========
l_T_tilde : Any (sympifiable)
Normalized tendon length.
c0 : Any (sympifiable)
The first constant in the characteristic equation. The published
value is ``0.2``.
c1 : Any (sympifiable)
The second constant in the characteristic equation. The published
value is ``0.995``.
c2 : Any (sympifiable)
The third constant in the characteristic equation. The published
value is ``0.25``.
c3 : Any (sympifiable)
The fourth constant in the characteristic equation. The published
value is ``33.93669377311689``.
"""
pass
def _eval_evalf(self, prec):
"""Evaluate the expression numerically using ``evalf``."""
return self.doit(deep=False, evaluate=False)._eval_evalf(prec)
def doit(self, deep=True, evaluate=True, **hints):
"""Evaluate the expression defining the function.
Parameters
==========
deep : bool
Whether ``doit`` should be recursively called. Default is ``True``.
evaluate : bool.
Whether the SymPy expression should be evaluated as it is
constructed. If ``False``, then no constant folding will be
conducted which will leave the expression in a more numerically-
stable for values of ``l_T_tilde`` that correspond to a sensible
operating range for a musculotendon. Default is ``True``.
**kwargs : dict[str, Any]
Additional keyword argument pairs to be recursively passed to
``doit``.
"""
l_T_tilde, *constants = self.args
if deep:
hints['evaluate'] = evaluate
l_T_tilde = l_T_tilde.doit(deep=deep, **hints)
c0, c1, c2, c3 = [c.doit(deep=deep, **hints) for c in constants]
else:
c0, c1, c2, c3 = constants
if evaluate:
return c0*exp(c3*(l_T_tilde - c1)) - c2
return c0*exp(c3*UnevaluatedExpr(l_T_tilde - c1)) - c2
def fdiff(self, argindex=1):
"""Derivative of the function with respect to a single argument.
Parameters
==========
argindex : int
The index of the function's arguments with respect to which the
derivative should be taken. Argument indexes start at ``1``.
Default is ``1``.
"""
l_T_tilde, c0, c1, c2, c3 = self.args
if argindex == 1:
return c0*c3*exp(c3*UnevaluatedExpr(l_T_tilde - c1))
elif argindex == 2:
return exp(c3*UnevaluatedExpr(l_T_tilde - c1))
elif argindex == 3:
return -c0*c3*exp(c3*UnevaluatedExpr(l_T_tilde - c1))
elif argindex == 4:
return Integer(-1)
elif argindex == 5:
return c0*(l_T_tilde - c1)*exp(c3*UnevaluatedExpr(l_T_tilde - c1))
raise ArgumentIndexError(self, argindex)
def inverse(self, argindex=1):
"""Inverse function.
Parameters
==========
argindex : int
Value to start indexing the arguments at. Default is ``1``.
"""
return TendonForceLengthInverseDeGroote2016
def _latex(self, printer):
"""Print a LaTeX representation of the function defining the curve.
Parameters
==========
printer : Printer
The printer to be used to print the LaTeX string representation.
"""
l_T_tilde = self.args[0]
_l_T_tilde = printer._print(l_T_tilde)
return r'\operatorname{fl}^T \left( %s \right)' % _l_T_tilde
class TendonForceLengthInverseDeGroote2016(CharacteristicCurveFunction):
r"""Inverse tendon force-length curve based on De Groote et al., 2016 [1]_.
Explanation
===========
Gives the normalized tendon length that produces a specific normalized
tendon force.
The function is defined by the equation:
${fl^T}^{-1} = frac{\log{\frac{fl^T + c_2}{c_0}}}{c_3} + c_1$
with constant values of $c_0 = 0.2$, $c_1 = 0.995$, $c_2 = 0.25$, and
$c_3 = 33.93669377311689$. This function is the exact analytical inverse
of the related tendon force-length curve ``TendonForceLengthDeGroote2016``.
While it is possible to change the constant values, these were carefully
selected in the original publication to give the characteristic curve
specific and required properties. For example, the function produces no
force when the tendon is in an unstrained state. It also produces a force
of 1 normalized unit when the tendon is under a 5% strain.
Examples
========
The preferred way to instantiate :class:`TendonForceLengthInverseDeGroote2016` is
using the :meth:`~.with_defaults` constructor because this will automatically
populate the constants within the characteristic curve equation with the
floating point values from the original publication. This constructor takes
a single argument corresponding to normalized tendon force-length, which is
equal to the tendon force. We'll create a :class:`~.Symbol` called ``fl_T`` to
represent this.
>>> from sympy import Symbol
>>> from sympy.physics.biomechanics import TendonForceLengthInverseDeGroote2016
>>> fl_T = Symbol('fl_T')
>>> l_T_tilde = TendonForceLengthInverseDeGroote2016.with_defaults(fl_T)
>>> l_T_tilde
TendonForceLengthInverseDeGroote2016(fl_T, 0.2, 0.995, 0.25,
33.93669377311689)
It's also possible to populate the four constants with your own values too.
>>> from sympy import symbols
>>> c0, c1, c2, c3 = symbols('c0 c1 c2 c3')
>>> l_T_tilde = TendonForceLengthInverseDeGroote2016(fl_T, c0, c1, c2, c3)
>>> l_T_tilde
TendonForceLengthInverseDeGroote2016(fl_T, c0, c1, c2, c3)
To inspect the actual symbolic expression that this function represents,
we can call the :meth:`~.doit` method on an instance. We'll use the keyword
argument ``evaluate=False`` as this will keep the expression in its
canonical form and won't simplify any constants.
>>> l_T_tilde.doit(evaluate=False)
c1 + log((c2 + fl_T)/c0)/c3
The function can also be differentiated. We'll differentiate with respect
to l_T using the ``diff`` method on an instance with the single positional
argument ``l_T``.
>>> l_T_tilde.diff(fl_T)
1/(c3*(c2 + fl_T))
References
==========
.. [1] De Groote, F., Kinney, A. L., Rao, A. V., & Fregly, B. J., Evaluation
of direct collocation optimal control problem formulations for
solving the muscle redundancy problem, Annals of biomedical
engineering, 44(10), (2016) pp. 2922-2936
"""
@classmethod
def with_defaults(cls, fl_T):
r"""Recommended constructor that will use the published constants.
Explanation
===========
Returns a new instance of the inverse tendon force-length function
using the four constant values specified in the original publication.
These have the values:
$c_0 = 0.2$
$c_1 = 0.995$
$c_2 = 0.25$
$c_3 = 33.93669377311689$
Parameters
==========
fl_T : Any (sympifiable)
Normalized tendon force as a function of tendon length.
"""
c0 = Float('0.2')
c1 = Float('0.995')
c2 = Float('0.25')
c3 = Float('33.93669377311689')
return cls(fl_T, c0, c1, c2, c3)
@classmethod
def eval(cls, fl_T, c0, c1, c2, c3):
"""Evaluation of basic inputs.
Parameters
==========
fl_T : Any (sympifiable)
Normalized tendon force as a function of tendon length.
c0 : Any (sympifiable)
The first constant in the characteristic equation. The published
value is ``0.2``.
c1 : Any (sympifiable)
The second constant in the characteristic equation. The published
value is ``0.995``.
c2 : Any (sympifiable)
The third constant in the characteristic equation. The published
value is ``0.25``.
c3 : Any (sympifiable)
The fourth constant in the characteristic equation. The published
value is ``33.93669377311689``.
"""
pass
def _eval_evalf(self, prec):
"""Evaluate the expression numerically using ``evalf``."""
return self.doit(deep=False, evaluate=False)._eval_evalf(prec)
def doit(self, deep=True, evaluate=True, **hints):
"""Evaluate the expression defining the function.
Parameters
==========
deep : bool
Whether ``doit`` should be recursively called. Default is ``True``.
evaluate : bool.
Whether the SymPy expression should be evaluated as it is
constructed. If ``False``, then no constant folding will be
conducted which will leave the expression in a more numerically-
stable for values of ``l_T_tilde`` that correspond to a sensible
operating range for a musculotendon. Default is ``True``.
**kwargs : dict[str, Any]
Additional keyword argument pairs to be recursively passed to
``doit``.
"""
fl_T, *constants = self.args
if deep:
hints['evaluate'] = evaluate
fl_T = fl_T.doit(deep=deep, **hints)
c0, c1, c2, c3 = [c.doit(deep=deep, **hints) for c in constants]
else:
c0, c1, c2, c3 = constants
if evaluate:
return log((fl_T + c2)/c0)/c3 + c1
return log(UnevaluatedExpr((fl_T + c2)/c0))/c3 + c1
def fdiff(self, argindex=1):
"""Derivative of the function with respect to a single argument.
Parameters
==========
argindex : int
The index of the function's arguments with respect to which the
derivative should be taken. Argument indexes start at ``1``.
Default is ``1``.
"""
fl_T, c0, c1, c2, c3 = self.args
if argindex == 1:
return 1/(c3*(fl_T + c2))
elif argindex == 2:
return -1/(c0*c3)
elif argindex == 3:
return Integer(1)
elif argindex == 4:
return 1/(c3*(fl_T + c2))
elif argindex == 5:
return -log(UnevaluatedExpr((fl_T + c2)/c0))/c3**2
raise ArgumentIndexError(self, argindex)
def inverse(self, argindex=1):
"""Inverse function.
Parameters
==========
argindex : int
Value to start indexing the arguments at. Default is ``1``.
"""
return TendonForceLengthDeGroote2016
def _latex(self, printer):
"""Print a LaTeX representation of the function defining the curve.
Parameters
==========
printer : Printer
The printer to be used to print the LaTeX string representation.
"""
fl_T = self.args[0]
_fl_T = printer._print(fl_T)
return r'\left( \operatorname{fl}^T \right)^{-1} \left( %s \right)' % _fl_T
class FiberForceLengthPassiveDeGroote2016(CharacteristicCurveFunction):
r"""Passive muscle fiber force-length curve based on De Groote et al., 2016
[1]_.
Explanation
===========
The function is defined by the equation:
$fl^M_{pas} = \frac{\frac{\exp{c_1 \left(\tilde{l^M} - 1\right)}}{c_0} - 1}{\exp{c_1} - 1}$
with constant values of $c_0 = 0.6$ and $c_1 = 4.0$.
While it is possible to change the constant values, these were carefully
selected in the original publication to give the characteristic curve
specific and required properties. For example, the function produces a
passive fiber force very close to 0 for all normalized fiber lengths
between 0 and 1.
Examples
========
The preferred way to instantiate :class:`FiberForceLengthPassiveDeGroote2016` is
using the :meth:`~.with_defaults` constructor because this will automatically
populate the constants within the characteristic curve equation with the
floating point values from the original publication. This constructor takes
a single argument corresponding to normalized muscle fiber length. We'll
create a :class:`~.Symbol` called ``l_M_tilde`` to represent this.
>>> from sympy import Symbol
>>> from sympy.physics.biomechanics import FiberForceLengthPassiveDeGroote2016
>>> l_M_tilde = Symbol('l_M_tilde')
>>> fl_M = FiberForceLengthPassiveDeGroote2016.with_defaults(l_M_tilde)
>>> fl_M
FiberForceLengthPassiveDeGroote2016(l_M_tilde, 0.6, 4.0)
It's also possible to populate the two constants with your own values too.
>>> from sympy import symbols
>>> c0, c1 = symbols('c0 c1')
>>> fl_M = FiberForceLengthPassiveDeGroote2016(l_M_tilde, c0, c1)
>>> fl_M
FiberForceLengthPassiveDeGroote2016(l_M_tilde, c0, c1)
You don't just have to use symbols as the arguments, it's also possible to
use expressions. Let's create a new pair of symbols, ``l_M`` and
``l_M_opt``, representing muscle fiber length and optimal muscle fiber
length respectively. We can then represent ``l_M_tilde`` as an expression,
the ratio of these.
>>> l_M, l_M_opt = symbols('l_M l_M_opt')
>>> l_M_tilde = l_M/l_M_opt
>>> fl_M = FiberForceLengthPassiveDeGroote2016.with_defaults(l_M_tilde)
>>> fl_M
FiberForceLengthPassiveDeGroote2016(l_M/l_M_opt, 0.6, 4.0)
To inspect the actual symbolic expression that this function represents,
we can call the :meth:`~.doit` method on an instance. We'll use the keyword
argument ``evaluate=False`` as this will keep the expression in its
canonical form and won't simplify any constants.
>>> fl_M.doit(evaluate=False)
0.0186573603637741*(-1 + exp(6.66666666666667*(l_M/l_M_opt - 1)))
The function can also be differentiated. We'll differentiate with respect
to l_M using the ``diff`` method on an instance with the single positional
argument ``l_M``.
>>> fl_M.diff(l_M)
0.12438240242516*exp(6.66666666666667*(l_M/l_M_opt - 1))/l_M_opt
References
==========
.. [1] De Groote, F., Kinney, A. L., Rao, A. V., & Fregly, B. J., Evaluation
of direct collocation optimal control problem formulations for
solving the muscle redundancy problem, Annals of biomedical
engineering, 44(10), (2016) pp. 2922-2936
"""
@classmethod
def with_defaults(cls, l_M_tilde):
r"""Recommended constructor that will use the published constants.
Explanation
===========
Returns a new instance of the muscle fiber passive force-length
function using the four constant values specified in the original
publication.
These have the values:
$c_0 = 0.6$
$c_1 = 4.0$
Parameters
==========
l_M_tilde : Any (sympifiable)
Normalized muscle fiber length.
"""
c0 = Float('0.6')
c1 = Float('4.0')
return cls(l_M_tilde, c0, c1)
@classmethod
def eval(cls, l_M_tilde, c0, c1):
"""Evaluation of basic inputs.
Parameters
==========
l_M_tilde : Any (sympifiable)
Normalized muscle fiber length.
c0 : Any (sympifiable)
The first constant in the characteristic equation. The published
value is ``0.6``.
c1 : Any (sympifiable)
The second constant in the characteristic equation. The published
value is ``4.0``.
"""
pass
def _eval_evalf(self, prec):
"""Evaluate the expression numerically using ``evalf``."""
return self.doit(deep=False, evaluate=False)._eval_evalf(prec)
def doit(self, deep=True, evaluate=True, **hints):
"""Evaluate the expression defining the function.
Parameters
==========
deep : bool
Whether ``doit`` should be recursively called. Default is ``True``.
evaluate : bool.
Whether the SymPy expression should be evaluated as it is
constructed. If ``False``, then no constant folding will be
conducted which will leave the expression in a more numerically-
stable for values of ``l_T_tilde`` that correspond to a sensible
operating range for a musculotendon. Default is ``True``.
**kwargs : dict[str, Any]
Additional keyword argument pairs to be recursively passed to
``doit``.
"""
l_M_tilde, *constants = self.args
if deep:
hints['evaluate'] = evaluate
l_M_tilde = l_M_tilde.doit(deep=deep, **hints)
c0, c1 = [c.doit(deep=deep, **hints) for c in constants]
else:
c0, c1 = constants
if evaluate:
return (exp((c1*(l_M_tilde - 1))/c0) - 1)/(exp(c1) - 1)
return (exp((c1*UnevaluatedExpr(l_M_tilde - 1))/c0) - 1)/(exp(c1) - 1)
def fdiff(self, argindex=1):
"""Derivative of the function with respect to a single argument.
Parameters
==========
argindex : int
The index of the function's arguments with respect to which the
derivative should be taken. Argument indexes start at ``1``.
Default is ``1``.
"""
l_M_tilde, c0, c1 = self.args
if argindex == 1:
return c1*exp(c1*UnevaluatedExpr(l_M_tilde - 1)/c0)/(c0*(exp(c1) - 1))
elif argindex == 2:
return (
-c1*exp(c1*UnevaluatedExpr(l_M_tilde - 1)/c0)
*UnevaluatedExpr(l_M_tilde - 1)/(c0**2*(exp(c1) - 1))
)
elif argindex == 3:
return (
-exp(c1)*(-1 + exp(c1*UnevaluatedExpr(l_M_tilde - 1)/c0))/(exp(c1) - 1)**2
+ exp(c1*UnevaluatedExpr(l_M_tilde - 1)/c0)*(l_M_tilde - 1)/(c0*(exp(c1) - 1))
)
raise ArgumentIndexError(self, argindex)
def inverse(self, argindex=1):
"""Inverse function.
Parameters
==========
argindex : int
Value to start indexing the arguments at. Default is ``1``.
"""
return FiberForceLengthPassiveInverseDeGroote2016
def _latex(self, printer):
"""Print a LaTeX representation of the function defining the curve.
Parameters
==========
printer : Printer
The printer to be used to print the LaTeX string representation.
"""
l_M_tilde = self.args[0]
_l_M_tilde = printer._print(l_M_tilde)
return r'\operatorname{fl}^M_{pas} \left( %s \right)' % _l_M_tilde
class FiberForceLengthPassiveInverseDeGroote2016(CharacteristicCurveFunction):
r"""Inverse passive muscle fiber force-length curve based on De Groote et
al., 2016 [1]_.
Explanation
===========
Gives the normalized muscle fiber length that produces a specific normalized
passive muscle fiber force.
The function is defined by the equation:
${fl^M_{pas}}^{-1} = \frac{c_0 \log{\left(\exp{c_1} - 1\right)fl^M_pas + 1}}{c_1} + 1$
with constant values of $c_0 = 0.6$ and $c_1 = 4.0$. This function is the
exact analytical inverse of the related tendon force-length curve
``FiberForceLengthPassiveDeGroote2016``.
While it is possible to change the constant values, these were carefully
selected in the original publication to give the characteristic curve
specific and required properties. For example, the function produces a
passive fiber force very close to 0 for all normalized fiber lengths
between 0 and 1.
Examples
========
The preferred way to instantiate
:class:`FiberForceLengthPassiveInverseDeGroote2016` is using the
:meth:`~.with_defaults` constructor because this will automatically populate the
constants within the characteristic curve equation with the floating point
values from the original publication. This constructor takes a single
argument corresponding to the normalized passive muscle fiber length-force
component of the muscle fiber force. We'll create a :class:`~.Symbol` called
``fl_M_pas`` to represent this.
>>> from sympy import Symbol
>>> from sympy.physics.biomechanics import FiberForceLengthPassiveInverseDeGroote2016
>>> fl_M_pas = Symbol('fl_M_pas')
>>> l_M_tilde = FiberForceLengthPassiveInverseDeGroote2016.with_defaults(fl_M_pas)
>>> l_M_tilde
FiberForceLengthPassiveInverseDeGroote2016(fl_M_pas, 0.6, 4.0)
It's also possible to populate the two constants with your own values too.
>>> from sympy import symbols
>>> c0, c1 = symbols('c0 c1')
>>> l_M_tilde = FiberForceLengthPassiveInverseDeGroote2016(fl_M_pas, c0, c1)
>>> l_M_tilde
FiberForceLengthPassiveInverseDeGroote2016(fl_M_pas, c0, c1)
To inspect the actual symbolic expression that this function represents,
we can call the :meth:`~.doit` method on an instance. We'll use the keyword
argument ``evaluate=False`` as this will keep the expression in its
canonical form and won't simplify any constants.
>>> l_M_tilde.doit(evaluate=False)
c0*log(1 + fl_M_pas*(exp(c1) - 1))/c1 + 1
The function can also be differentiated. We'll differentiate with respect
to fl_M_pas using the ``diff`` method on an instance with the single positional
argument ``fl_M_pas``.
>>> l_M_tilde.diff(fl_M_pas)
c0*(exp(c1) - 1)/(c1*(fl_M_pas*(exp(c1) - 1) + 1))
References
==========
.. [1] De Groote, F., Kinney, A. L., Rao, A. V., & Fregly, B. J., Evaluation
of direct collocation optimal control problem formulations for
solving the muscle redundancy problem, Annals of biomedical
engineering, 44(10), (2016) pp. 2922-2936
"""
@classmethod
def with_defaults(cls, fl_M_pas):
r"""Recommended constructor that will use the published constants.
Explanation
===========
Returns a new instance of the inverse muscle fiber passive force-length
function using the four constant values specified in the original
publication.
These have the values:
$c_0 = 0.6$
$c_1 = 4.0$
Parameters
==========
fl_M_pas : Any (sympifiable)
Normalized passive muscle fiber force as a function of muscle fiber
length.
"""
c0 = Float('0.6')
c1 = Float('4.0')
return cls(fl_M_pas, c0, c1)
@classmethod
def eval(cls, fl_M_pas, c0, c1):
"""Evaluation of basic inputs.
Parameters
==========
fl_M_pas : Any (sympifiable)
Normalized passive muscle fiber force.
c0 : Any (sympifiable)
The first constant in the characteristic equation. The published
value is ``0.6``.
c1 : Any (sympifiable)
The second constant in the characteristic equation. The published
value is ``4.0``.
"""
pass
def _eval_evalf(self, prec):
"""Evaluate the expression numerically using ``evalf``."""
return self.doit(deep=False, evaluate=False)._eval_evalf(prec)
def doit(self, deep=True, evaluate=True, **hints):
"""Evaluate the expression defining the function.
Parameters
==========
deep : bool
Whether ``doit`` should be recursively called. Default is ``True``.
evaluate : bool.
Whether the SymPy expression should be evaluated as it is
constructed. If ``False``, then no constant folding will be
conducted which will leave the expression in a more numerically-
stable for values of ``l_T_tilde`` that correspond to a sensible
operating range for a musculotendon. Default is ``True``.
**kwargs : dict[str, Any]
Additional keyword argument pairs to be recursively passed to
``doit``.
"""
fl_M_pas, *constants = self.args
if deep:
hints['evaluate'] = evaluate
fl_M_pas = fl_M_pas.doit(deep=deep, **hints)
c0, c1 = [c.doit(deep=deep, **hints) for c in constants]
else:
c0, c1 = constants
if evaluate:
return c0*log(fl_M_pas*(exp(c1) - 1) + 1)/c1 + 1
return c0*log(UnevaluatedExpr(fl_M_pas*(exp(c1) - 1)) + 1)/c1 + 1
def fdiff(self, argindex=1):
"""Derivative of the function with respect to a single argument.
Parameters
==========
argindex : int
The index of the function's arguments with respect to which the
derivative should be taken. Argument indexes start at ``1``.
Default is ``1``.
"""
fl_M_pas, c0, c1 = self.args
if argindex == 1:
return c0*(exp(c1) - 1)/(c1*(fl_M_pas*(exp(c1) - 1) + 1))
elif argindex == 2:
return log(fl_M_pas*(exp(c1) - 1) + 1)/c1
elif argindex == 3:
return (
c0*fl_M_pas*exp(c1)/(c1*(fl_M_pas*(exp(c1) - 1) + 1))
- c0*log(fl_M_pas*(exp(c1) - 1) + 1)/c1**2
)
raise ArgumentIndexError(self, argindex)
def inverse(self, argindex=1):
"""Inverse function.
Parameters
==========
argindex : int
Value to start indexing the arguments at. Default is ``1``.
"""
return FiberForceLengthPassiveDeGroote2016
def _latex(self, printer):
"""Print a LaTeX representation of the function defining the curve.
Parameters
==========
printer : Printer
The printer to be used to print the LaTeX string representation.
"""
fl_M_pas = self.args[0]
_fl_M_pas = printer._print(fl_M_pas)
return r'\left( \operatorname{fl}^M_{pas} \right)^{-1} \left( %s \right)' % _fl_M_pas
class FiberForceLengthActiveDeGroote2016(CharacteristicCurveFunction):
r"""Active muscle fiber force-length curve based on De Groote et al., 2016
[1]_.
Explanation
===========
The function is defined by the equation:
$fl_{\text{act}}^M = c_0 \exp\left(-\frac{1}{2}\left(\frac{\tilde{l}^M - c_1}{c_2 + c_3 \tilde{l}^M}\right)^2\right)
+ c_4 \exp\left(-\frac{1}{2}\left(\frac{\tilde{l}^M - c_5}{c_6 + c_7 \tilde{l}^M}\right)^2\right)
+ c_8 \exp\left(-\frac{1}{2}\left(\frac{\tilde{l}^M - c_9}{c_{10} + c_{11} \tilde{l}^M}\right)^2\right)$
with constant values of $c0 = 0.814$, $c1 = 1.06$, $c2 = 0.162$,
$c3 = 0.0633$, $c4 = 0.433$, $c5 = 0.717$, $c6 = -0.0299$, $c7 = 0.2$,
$c8 = 0.1$, $c9 = 1.0$, $c10 = 0.354$, and $c11 = 0.0$.
While it is possible to change the constant values, these were carefully
selected in the original publication to give the characteristic curve
specific and required properties. For example, the function produces a
active fiber force of 1 at a normalized fiber length of 1, and an active
fiber force of 0 at normalized fiber lengths of 0 and 2.
Examples
========
The preferred way to instantiate :class:`FiberForceLengthActiveDeGroote2016` is
using the :meth:`~.with_defaults` constructor because this will automatically
populate the constants within the characteristic curve equation with the
floating point values from the original publication. This constructor takes
a single argument corresponding to normalized muscle fiber length. We'll
create a :class:`~.Symbol` called ``l_M_tilde`` to represent this.
>>> from sympy import Symbol
>>> from sympy.physics.biomechanics import FiberForceLengthActiveDeGroote2016
>>> l_M_tilde = Symbol('l_M_tilde')
>>> fl_M = FiberForceLengthActiveDeGroote2016.with_defaults(l_M_tilde)
>>> fl_M
FiberForceLengthActiveDeGroote2016(l_M_tilde, 0.814, 1.06, 0.162, 0.0633,
0.433, 0.717, -0.0299, 0.2, 0.1, 1.0, 0.354, 0.0)
It's also possible to populate the two constants with your own values too.
>>> from sympy import symbols
>>> c0, c1, c2, c3, c4, c5, c6, c7, c8, c9, c10, c11 = symbols('c0:12')
>>> fl_M = FiberForceLengthActiveDeGroote2016(l_M_tilde, c0, c1, c2, c3,
... c4, c5, c6, c7, c8, c9, c10, c11)
>>> fl_M
FiberForceLengthActiveDeGroote2016(l_M_tilde, c0, c1, c2, c3, c4, c5, c6,
c7, c8, c9, c10, c11)
You don't just have to use symbols as the arguments, it's also possible to
use expressions. Let's create a new pair of symbols, ``l_M`` and
``l_M_opt``, representing muscle fiber length and optimal muscle fiber
length respectively. We can then represent ``l_M_tilde`` as an expression,
the ratio of these.
>>> l_M, l_M_opt = symbols('l_M l_M_opt')
>>> l_M_tilde = l_M/l_M_opt
>>> fl_M = FiberForceLengthActiveDeGroote2016.with_defaults(l_M_tilde)
>>> fl_M
FiberForceLengthActiveDeGroote2016(l_M/l_M_opt, 0.814, 1.06, 0.162, 0.0633,
0.433, 0.717, -0.0299, 0.2, 0.1, 1.0, 0.354, 0.0)
To inspect the actual symbolic expression that this function represents,
we can call the :meth:`~.doit` method on an instance. We'll use the keyword
argument ``evaluate=False`` as this will keep the expression in its
canonical form and won't simplify any constants.
>>> fl_M.doit(evaluate=False)
0.814*exp(-19.0519737844841*(l_M/l_M_opt
- 1.06)**2/(0.390740740740741*l_M/l_M_opt + 1)**2)
+ 0.433*exp(-12.5*(l_M/l_M_opt - 0.717)**2/(l_M/l_M_opt - 0.1495)**2)
+ 0.1*exp(-3.98991349867535*(l_M/l_M_opt - 1.0)**2)
The function can also be differentiated. We'll differentiate with respect
to l_M using the ``diff`` method on an instance with the single positional
argument ``l_M``.
>>> fl_M.diff(l_M)
((-0.79798269973507*l_M/l_M_opt
+ 0.79798269973507)*exp(-3.98991349867535*(l_M/l_M_opt - 1.0)**2)
+ (10.825*(-l_M/l_M_opt + 0.717)/(l_M/l_M_opt - 0.1495)**2
+ 10.825*(l_M/l_M_opt - 0.717)**2/(l_M/l_M_opt
- 0.1495)**3)*exp(-12.5*(l_M/l_M_opt - 0.717)**2/(l_M/l_M_opt - 0.1495)**2)
+ (31.0166133211401*(-l_M/l_M_opt + 1.06)/(0.390740740740741*l_M/l_M_opt
+ 1)**2 + 13.6174190361677*(0.943396226415094*l_M/l_M_opt
- 1)**2/(0.390740740740741*l_M/l_M_opt
+ 1)**3)*exp(-21.4067977442463*(0.943396226415094*l_M/l_M_opt
- 1)**2/(0.390740740740741*l_M/l_M_opt + 1)**2))/l_M_opt
References
==========
.. [1] De Groote, F., Kinney, A. L., Rao, A. V., & Fregly, B. J., Evaluation
of direct collocation optimal control problem formulations for
solving the muscle redundancy problem, Annals of biomedical
engineering, 44(10), (2016) pp. 2922-2936
"""
@classmethod
def with_defaults(cls, l_M_tilde):
r"""Recommended constructor that will use the published constants.
Explanation
===========
Returns a new instance of the inverse muscle fiber act force-length
function using the four constant values specified in the original
publication.
These have the values:
$c0 = 0.814$
$c1 = 1.06$
$c2 = 0.162$
$c3 = 0.0633$
$c4 = 0.433$
$c5 = 0.717$
$c6 = -0.0299$
$c7 = 0.2$
$c8 = 0.1$
$c9 = 1.0$
$c10 = 0.354$
$c11 = 0.0$
Parameters
==========
fl_M_act : Any (sympifiable)
Normalized passive muscle fiber force as a function of muscle fiber
length.
"""
c0 = Float('0.814')
c1 = Float('1.06')
c2 = Float('0.162')
c3 = Float('0.0633')
c4 = Float('0.433')
c5 = Float('0.717')
c6 = Float('-0.0299')
c7 = Float('0.2')
c8 = Float('0.1')
c9 = Float('1.0')
c10 = Float('0.354')
c11 = Float('0.0')
return cls(l_M_tilde, c0, c1, c2, c3, c4, c5, c6, c7, c8, c9, c10, c11)
@classmethod
def eval(cls, l_M_tilde, c0, c1, c2, c3, c4, c5, c6, c7, c8, c9, c10, c11):
"""Evaluation of basic inputs.
Parameters
==========
l_M_tilde : Any (sympifiable)
Normalized muscle fiber length.
c0 : Any (sympifiable)
The first constant in the characteristic equation. The published
value is ``0.814``.
c1 : Any (sympifiable)
The second constant in the characteristic equation. The published
value is ``1.06``.
c2 : Any (sympifiable)
The third constant in the characteristic equation. The published
value is ``0.162``.
c3 : Any (sympifiable)
The fourth constant in the characteristic equation. The published
value is ``0.0633``.
c4 : Any (sympifiable)
The fifth constant in the characteristic equation. The published
value is ``0.433``.
c5 : Any (sympifiable)
The sixth constant in the characteristic equation. The published
value is ``0.717``.
c6 : Any (sympifiable)
The seventh constant in the characteristic equation. The published
value is ``-0.0299``.
c7 : Any (sympifiable)
The eighth constant in the characteristic equation. The published
value is ``0.2``.
c8 : Any (sympifiable)
The ninth constant in the characteristic equation. The published
value is ``0.1``.
c9 : Any (sympifiable)
The tenth constant in the characteristic equation. The published
value is ``1.0``.
c10 : Any (sympifiable)
The eleventh constant in the characteristic equation. The published
value is ``0.354``.
c11 : Any (sympifiable)
The tweflth constant in the characteristic equation. The published
value is ``0.0``.
"""
pass
def _eval_evalf(self, prec):
"""Evaluate the expression numerically using ``evalf``."""
return self.doit(deep=False, evaluate=False)._eval_evalf(prec)
def doit(self, deep=True, evaluate=True, **hints):
"""Evaluate the expression defining the function.
Parameters
==========
deep : bool
Whether ``doit`` should be recursively called. Default is ``True``.
evaluate : bool.
Whether the SymPy expression should be evaluated as it is
constructed. If ``False``, then no constant folding will be
conducted which will leave the expression in a more numerically-
stable for values of ``l_M_tilde`` that correspond to a sensible
operating range for a musculotendon. Default is ``True``.
**kwargs : dict[str, Any]
Additional keyword argument pairs to be recursively passed to
``doit``.
"""
l_M_tilde, *constants = self.args
if deep:
hints['evaluate'] = evaluate
l_M_tilde = l_M_tilde.doit(deep=deep, **hints)
constants = [c.doit(deep=deep, **hints) for c in constants]
c0, c1, c2, c3, c4, c5, c6, c7, c8, c9, c10, c11 = constants
if evaluate:
return (
c0*exp(-(((l_M_tilde - c1)/(c2 + c3*l_M_tilde))**2)/2)
+ c4*exp(-(((l_M_tilde - c5)/(c6 + c7*l_M_tilde))**2)/2)
+ c8*exp(-(((l_M_tilde - c9)/(c10 + c11*l_M_tilde))**2)/2)
)
return (
c0*exp(-((UnevaluatedExpr(l_M_tilde - c1)/(c2 + c3*l_M_tilde))**2)/2)
+ c4*exp(-((UnevaluatedExpr(l_M_tilde - c5)/(c6 + c7*l_M_tilde))**2)/2)
+ c8*exp(-((UnevaluatedExpr(l_M_tilde - c9)/(c10 + c11*l_M_tilde))**2)/2)
)
def fdiff(self, argindex=1):
"""Derivative of the function with respect to a single argument.
Parameters
==========
argindex : int
The index of the function's arguments with respect to which the
derivative should be taken. Argument indexes start at ``1``.
Default is ``1``.
"""
l_M_tilde, c0, c1, c2, c3, c4, c5, c6, c7, c8, c9, c10, c11 = self.args
if argindex == 1:
return (
c0*(
c3*(l_M_tilde - c1)**2/(c2 + c3*l_M_tilde)**3
+ (c1 - l_M_tilde)/((c2 + c3*l_M_tilde)**2)
)*exp(-(l_M_tilde - c1)**2/(2*(c2 + c3*l_M_tilde)**2))
+ c4*(
c7*(l_M_tilde - c5)**2/(c6 + c7*l_M_tilde)**3
+ (c5 - l_M_tilde)/((c6 + c7*l_M_tilde)**2)
)*exp(-(l_M_tilde - c5)**2/(2*(c6 + c7*l_M_tilde)**2))
+ c8*(
c11*(l_M_tilde - c9)**2/(c10 + c11*l_M_tilde)**3
+ (c9 - l_M_tilde)/((c10 + c11*l_M_tilde)**2)
)*exp(-(l_M_tilde - c9)**2/(2*(c10 + c11*l_M_tilde)**2))
)
elif argindex == 2:
return exp(-(l_M_tilde - c1)**2/(2*(c2 + c3*l_M_tilde)**2))
elif argindex == 3:
return (
c0*(l_M_tilde - c1)/(c2 + c3*l_M_tilde)**2
*exp(-(l_M_tilde - c1)**2 /(2*(c2 + c3*l_M_tilde)**2))
)
elif argindex == 4:
return (
c0*(l_M_tilde - c1)**2/(c2 + c3*l_M_tilde)**3
*exp(-(l_M_tilde - c1)**2/(2*(c2 + c3*l_M_tilde)**2))
)
elif argindex == 5:
return (
c0*l_M_tilde*(l_M_tilde - c1)**2/(c2 + c3*l_M_tilde)**3
*exp(-(l_M_tilde - c1)**2/(2*(c2 + c3*l_M_tilde)**2))
)
elif argindex == 6:
return exp(-(l_M_tilde - c5)**2/(2*(c6 + c7*l_M_tilde)**2))
elif argindex == 7:
return (
c4*(l_M_tilde - c5)/(c6 + c7*l_M_tilde)**2
*exp(-(l_M_tilde - c5)**2 /(2*(c6 + c7*l_M_tilde)**2))
)
elif argindex == 8:
return (
c4*(l_M_tilde - c5)**2/(c6 + c7*l_M_tilde)**3
*exp(-(l_M_tilde - c5)**2/(2*(c6 + c7*l_M_tilde)**2))
)
elif argindex == 9:
return (
c4*l_M_tilde*(l_M_tilde - c5)**2/(c6 + c7*l_M_tilde)**3
*exp(-(l_M_tilde - c5)**2/(2*(c6 + c7*l_M_tilde)**2))
)
elif argindex == 10:
return exp(-(l_M_tilde - c9)**2/(2*(c10 + c11*l_M_tilde)**2))
elif argindex == 11:
return (
c8*(l_M_tilde - c9)/(c10 + c11*l_M_tilde)**2
*exp(-(l_M_tilde - c9)**2 /(2*(c10 + c11*l_M_tilde)**2))
)
elif argindex == 12:
return (
c8*(l_M_tilde - c9)**2/(c10 + c11*l_M_tilde)**3
*exp(-(l_M_tilde - c9)**2/(2*(c10 + c11*l_M_tilde)**2))
)
elif argindex == 13:
return (
c8*l_M_tilde*(l_M_tilde - c9)**2/(c10 + c11*l_M_tilde)**3
*exp(-(l_M_tilde - c9)**2/(2*(c10 + c11*l_M_tilde)**2))
)
raise ArgumentIndexError(self, argindex)
def _latex(self, printer):
"""Print a LaTeX representation of the function defining the curve.
Parameters
==========
printer : Printer
The printer to be used to print the LaTeX string representation.
"""
l_M_tilde = self.args[0]
_l_M_tilde = printer._print(l_M_tilde)
return r'\operatorname{fl}^M_{act} \left( %s \right)' % _l_M_tilde
class FiberForceVelocityDeGroote2016(CharacteristicCurveFunction):
r"""Muscle fiber force-velocity curve based on De Groote et al., 2016 [1]_.
Explanation
===========
Gives the normalized muscle fiber force produced as a function of
normalized tendon velocity.
The function is defined by the equation:
$fv^M = c_0 \log{\left(c_1 \tilde{v}_m + c_2\right) + \sqrt{\left(c_1 \tilde{v}_m + c_2\right)^2 + 1}} + c_3$
with constant values of $c_0 = -0.318$, $c_1 = -8.149$, $c_2 = -0.374$, and
$c_3 = 0.886$.
While it is possible to change the constant values, these were carefully
selected in the original publication to give the characteristic curve
specific and required properties. For example, the function produces a
normalized muscle fiber force of 1 when the muscle fibers are contracting
isometrically (they have an extension rate of 0).
Examples
========
The preferred way to instantiate :class:`FiberForceVelocityDeGroote2016` is using
the :meth:`~.with_defaults` constructor because this will automatically populate
the constants within the characteristic curve equation with the floating
point values from the original publication. This constructor takes a single
argument corresponding to normalized muscle fiber extension velocity. We'll
create a :class:`~.Symbol` called ``v_M_tilde`` to represent this.
>>> from sympy import Symbol
>>> from sympy.physics.biomechanics import FiberForceVelocityDeGroote2016
>>> v_M_tilde = Symbol('v_M_tilde')
>>> fv_M = FiberForceVelocityDeGroote2016.with_defaults(v_M_tilde)
>>> fv_M
FiberForceVelocityDeGroote2016(v_M_tilde, -0.318, -8.149, -0.374, 0.886)
It's also possible to populate the four constants with your own values too.
>>> from sympy import symbols
>>> c0, c1, c2, c3 = symbols('c0 c1 c2 c3')
>>> fv_M = FiberForceVelocityDeGroote2016(v_M_tilde, c0, c1, c2, c3)
>>> fv_M
FiberForceVelocityDeGroote2016(v_M_tilde, c0, c1, c2, c3)
You don't just have to use symbols as the arguments, it's also possible to
use expressions. Let's create a new pair of symbols, ``v_M`` and
``v_M_max``, representing muscle fiber extension velocity and maximum
muscle fiber extension velocity respectively. We can then represent
``v_M_tilde`` as an expression, the ratio of these.
>>> v_M, v_M_max = symbols('v_M v_M_max')
>>> v_M_tilde = v_M/v_M_max
>>> fv_M = FiberForceVelocityDeGroote2016.with_defaults(v_M_tilde)
>>> fv_M
FiberForceVelocityDeGroote2016(v_M/v_M_max, -0.318, -8.149, -0.374, 0.886)
To inspect the actual symbolic expression that this function represents,
we can call the :meth:`~.doit` method on an instance. We'll use the keyword
argument ``evaluate=False`` as this will keep the expression in its
canonical form and won't simplify any constants.
>>> fv_M.doit(evaluate=False)
0.886 - 0.318*log(-8.149*v_M/v_M_max - 0.374 + sqrt(1 + (-8.149*v_M/v_M_max
- 0.374)**2))
The function can also be differentiated. We'll differentiate with respect
to v_M using the ``diff`` method on an instance with the single positional
argument ``v_M``.
>>> fv_M.diff(v_M)
2.591382*(1 + (-8.149*v_M/v_M_max - 0.374)**2)**(-1/2)/v_M_max
References
==========
.. [1] De Groote, F., Kinney, A. L., Rao, A. V., & Fregly, B. J., Evaluation
of direct collocation optimal control problem formulations for
solving the muscle redundancy problem, Annals of biomedical
engineering, 44(10), (2016) pp. 2922-2936
"""
@classmethod
def with_defaults(cls, v_M_tilde):
r"""Recommended constructor that will use the published constants.
Explanation
===========
Returns a new instance of the muscle fiber force-velocity function
using the four constant values specified in the original publication.
These have the values:
$c_0 = -0.318$
$c_1 = -8.149$
$c_2 = -0.374$
$c_3 = 0.886$
Parameters
==========
v_M_tilde : Any (sympifiable)
Normalized muscle fiber extension velocity.
"""
c0 = Float('-0.318')
c1 = Float('-8.149')
c2 = Float('-0.374')
c3 = Float('0.886')
return cls(v_M_tilde, c0, c1, c2, c3)
@classmethod
def eval(cls, v_M_tilde, c0, c1, c2, c3):
"""Evaluation of basic inputs.
Parameters
==========
v_M_tilde : Any (sympifiable)
Normalized muscle fiber extension velocity.
c0 : Any (sympifiable)
The first constant in the characteristic equation. The published
value is ``-0.318``.
c1 : Any (sympifiable)
The second constant in the characteristic equation. The published
value is ``-8.149``.
c2 : Any (sympifiable)
The third constant in the characteristic equation. The published
value is ``-0.374``.
c3 : Any (sympifiable)
The fourth constant in the characteristic equation. The published
value is ``0.886``.
"""
pass
def _eval_evalf(self, prec):
"""Evaluate the expression numerically using ``evalf``."""
return self.doit(deep=False, evaluate=False)._eval_evalf(prec)
def doit(self, deep=True, evaluate=True, **hints):
"""Evaluate the expression defining the function.
Parameters
==========
deep : bool
Whether ``doit`` should be recursively called. Default is ``True``.
evaluate : bool.
Whether the SymPy expression should be evaluated as it is
constructed. If ``False``, then no constant folding will be
conducted which will leave the expression in a more numerically-
stable for values of ``v_M_tilde`` that correspond to a sensible
operating range for a musculotendon. Default is ``True``.
**kwargs : dict[str, Any]
Additional keyword argument pairs to be recursively passed to
``doit``.
"""
v_M_tilde, *constants = self.args
if deep:
hints['evaluate'] = evaluate
v_M_tilde = v_M_tilde.doit(deep=deep, **hints)
c0, c1, c2, c3 = [c.doit(deep=deep, **hints) for c in constants]
else:
c0, c1, c2, c3 = constants
if evaluate:
return c0*log(c1*v_M_tilde + c2 + sqrt((c1*v_M_tilde + c2)**2 + 1)) + c3
return c0*log(c1*v_M_tilde + c2 + sqrt(UnevaluatedExpr(c1*v_M_tilde + c2)**2 + 1)) + c3
def fdiff(self, argindex=1):
"""Derivative of the function with respect to a single argument.
Parameters
==========
argindex : int
The index of the function's arguments with respect to which the
derivative should be taken. Argument indexes start at ``1``.
Default is ``1``.
"""
v_M_tilde, c0, c1, c2, c3 = self.args
if argindex == 1:
return c0*c1/sqrt(UnevaluatedExpr(c1*v_M_tilde + c2)**2 + 1)
elif argindex == 2:
return log(
c1*v_M_tilde + c2
+ sqrt(UnevaluatedExpr(c1*v_M_tilde + c2)**2 + 1)
)
elif argindex == 3:
return c0*v_M_tilde/sqrt(UnevaluatedExpr(c1*v_M_tilde + c2)**2 + 1)
elif argindex == 4:
return c0/sqrt(UnevaluatedExpr(c1*v_M_tilde + c2)**2 + 1)
elif argindex == 5:
return Integer(1)
raise ArgumentIndexError(self, argindex)
def inverse(self, argindex=1):
"""Inverse function.
Parameters
==========
argindex : int
Value to start indexing the arguments at. Default is ``1``.
"""
return FiberForceVelocityInverseDeGroote2016
def _latex(self, printer):
"""Print a LaTeX representation of the function defining the curve.
Parameters
==========
printer : Printer
The printer to be used to print the LaTeX string representation.
"""
v_M_tilde = self.args[0]
_v_M_tilde = printer._print(v_M_tilde)
return r'\operatorname{fv}^M \left( %s \right)' % _v_M_tilde
class FiberForceVelocityInverseDeGroote2016(CharacteristicCurveFunction):
r"""Inverse muscle fiber force-velocity curve based on De Groote et al.,
2016 [1]_.
Explanation
===========
Gives the normalized muscle fiber velocity that produces a specific
normalized muscle fiber force.
The function is defined by the equation:
${fv^M}^{-1} = \frac{\sinh{\frac{fv^M - c_3}{c_0}} - c_2}{c_1}$
with constant values of $c_0 = -0.318$, $c_1 = -8.149$, $c_2 = -0.374$, and
$c_3 = 0.886$. This function is the exact analytical inverse of the related
muscle fiber force-velocity curve ``FiberForceVelocityDeGroote2016``.
While it is possible to change the constant values, these were carefully
selected in the original publication to give the characteristic curve
specific and required properties. For example, the function produces a
normalized muscle fiber force of 1 when the muscle fibers are contracting
isometrically (they have an extension rate of 0).
Examples
========
The preferred way to instantiate :class:`FiberForceVelocityInverseDeGroote2016`
is using the :meth:`~.with_defaults` constructor because this will automatically
populate the constants within the characteristic curve equation with the
floating point values from the original publication. This constructor takes
a single argument corresponding to normalized muscle fiber force-velocity
component of the muscle fiber force. We'll create a :class:`~.Symbol` called
``fv_M`` to represent this.
>>> from sympy import Symbol
>>> from sympy.physics.biomechanics import FiberForceVelocityInverseDeGroote2016
>>> fv_M = Symbol('fv_M')
>>> v_M_tilde = FiberForceVelocityInverseDeGroote2016.with_defaults(fv_M)
>>> v_M_tilde
FiberForceVelocityInverseDeGroote2016(fv_M, -0.318, -8.149, -0.374, 0.886)
It's also possible to populate the four constants with your own values too.
>>> from sympy import symbols
>>> c0, c1, c2, c3 = symbols('c0 c1 c2 c3')
>>> v_M_tilde = FiberForceVelocityInverseDeGroote2016(fv_M, c0, c1, c2, c3)
>>> v_M_tilde
FiberForceVelocityInverseDeGroote2016(fv_M, c0, c1, c2, c3)
To inspect the actual symbolic expression that this function represents,
we can call the :meth:`~.doit` method on an instance. We'll use the keyword
argument ``evaluate=False`` as this will keep the expression in its
canonical form and won't simplify any constants.
>>> v_M_tilde.doit(evaluate=False)
(-c2 + sinh((-c3 + fv_M)/c0))/c1
The function can also be differentiated. We'll differentiate with respect
to fv_M using the ``diff`` method on an instance with the single positional
argument ``fv_M``.
>>> v_M_tilde.diff(fv_M)
cosh((-c3 + fv_M)/c0)/(c0*c1)
References
==========
.. [1] De Groote, F., Kinney, A. L., Rao, A. V., & Fregly, B. J., Evaluation
of direct collocation optimal control problem formulations for
solving the muscle redundancy problem, Annals of biomedical
engineering, 44(10), (2016) pp. 2922-2936
"""
@classmethod
def with_defaults(cls, fv_M):
r"""Recommended constructor that will use the published constants.
Explanation
===========
Returns a new instance of the inverse muscle fiber force-velocity
function using the four constant values specified in the original
publication.
These have the values:
$c_0 = -0.318$
$c_1 = -8.149$
$c_2 = -0.374$
$c_3 = 0.886$
Parameters
==========
fv_M : Any (sympifiable)
Normalized muscle fiber extension velocity.
"""
c0 = Float('-0.318')
c1 = Float('-8.149')
c2 = Float('-0.374')
c3 = Float('0.886')
return cls(fv_M, c0, c1, c2, c3)
@classmethod
def eval(cls, fv_M, c0, c1, c2, c3):
"""Evaluation of basic inputs.
Parameters
==========
fv_M : Any (sympifiable)
Normalized muscle fiber force as a function of muscle fiber
extension velocity.
c0 : Any (sympifiable)
The first constant in the characteristic equation. The published
value is ``-0.318``.
c1 : Any (sympifiable)
The second constant in the characteristic equation. The published
value is ``-8.149``.
c2 : Any (sympifiable)
The third constant in the characteristic equation. The published
value is ``-0.374``.
c3 : Any (sympifiable)
The fourth constant in the characteristic equation. The published
value is ``0.886``.
"""
pass
def _eval_evalf(self, prec):
"""Evaluate the expression numerically using ``evalf``."""
return self.doit(deep=False, evaluate=False)._eval_evalf(prec)
def doit(self, deep=True, evaluate=True, **hints):
"""Evaluate the expression defining the function.
Parameters
==========
deep : bool
Whether ``doit`` should be recursively called. Default is ``True``.
evaluate : bool.
Whether the SymPy expression should be evaluated as it is
constructed. If ``False``, then no constant folding will be
conducted which will leave the expression in a more numerically-
stable for values of ``fv_M`` that correspond to a sensible
operating range for a musculotendon. Default is ``True``.
**kwargs : dict[str, Any]
Additional keyword argument pairs to be recursively passed to
``doit``.
"""
fv_M, *constants = self.args
if deep:
hints['evaluate'] = evaluate
fv_M = fv_M.doit(deep=deep, **hints)
c0, c1, c2, c3 = [c.doit(deep=deep, **hints) for c in constants]
else:
c0, c1, c2, c3 = constants
if evaluate:
return (sinh((fv_M - c3)/c0) - c2)/c1
return (sinh(UnevaluatedExpr(fv_M - c3)/c0) - c2)/c1
def fdiff(self, argindex=1):
"""Derivative of the function with respect to a single argument.
Parameters
==========
argindex : int
The index of the function's arguments with respect to which the
derivative should be taken. Argument indexes start at ``1``.
Default is ``1``.
"""
fv_M, c0, c1, c2, c3 = self.args
if argindex == 1:
return cosh((fv_M - c3)/c0)/(c0*c1)
elif argindex == 2:
return (c3 - fv_M)*cosh((fv_M - c3)/c0)/(c0**2*c1)
elif argindex == 3:
return (c2 - sinh((fv_M - c3)/c0))/c1**2
elif argindex == 4:
return -1/c1
elif argindex == 5:
return -cosh((fv_M - c3)/c0)/(c0*c1)
raise ArgumentIndexError(self, argindex)
def inverse(self, argindex=1):
"""Inverse function.
Parameters
==========
argindex : int
Value to start indexing the arguments at. Default is ``1``.
"""
return FiberForceVelocityDeGroote2016
def _latex(self, printer):
"""Print a LaTeX representation of the function defining the curve.
Parameters
==========
printer : Printer
The printer to be used to print the LaTeX string representation.
"""
fv_M = self.args[0]
_fv_M = printer._print(fv_M)
return r'\left( \operatorname{fv}^M \right)^{-1} \left( %s \right)' % _fv_M
@dataclass(frozen=True)
class CharacteristicCurveCollection:
"""Simple data container to group together related characteristic curves."""
tendon_force_length: CharacteristicCurveFunction
tendon_force_length_inverse: CharacteristicCurveFunction
fiber_force_length_passive: CharacteristicCurveFunction
fiber_force_length_passive_inverse: CharacteristicCurveFunction
fiber_force_length_active: CharacteristicCurveFunction
fiber_force_velocity: CharacteristicCurveFunction
fiber_force_velocity_inverse: CharacteristicCurveFunction
def __iter__(self):
"""Iterator support for ``CharacteristicCurveCollection``."""
yield self.tendon_force_length
yield self.tendon_force_length_inverse
yield self.fiber_force_length_passive
yield self.fiber_force_length_passive_inverse
yield self.fiber_force_length_active
yield self.fiber_force_velocity
yield self.fiber_force_velocity_inverse
PK ]ZZZރ��� �� + sympy/physics/biomechanics/musculotendon.py"""Implementations of musculotendon models.
Musculotendon models are a critical component of biomechanical models, one that
differentiates them from pure multibody systems. Musculotendon models produce a
force dependent on their level of activation, their length, and their
extension velocity. Length- and extension velocity-dependent force production
are governed by force-length and force-velocity characteristics.
These are normalized functions that are dependent on the musculotendon's state
and are specific to a given musculotendon model.
"""
from abc import abstractmethod
from enum import IntEnum, unique
from sympy.core.numbers import Float, Integer
from sympy.core.symbol import Symbol, symbols
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.elementary.trigonometric import cos, sin
from sympy.matrices.dense import MutableDenseMatrix as Matrix, diag, eye, zeros
from sympy.physics.biomechanics.activation import ActivationBase
from sympy.physics.biomechanics.curve import (
CharacteristicCurveCollection,
FiberForceLengthActiveDeGroote2016,
FiberForceLengthPassiveDeGroote2016,
FiberForceLengthPassiveInverseDeGroote2016,
FiberForceVelocityDeGroote2016,
FiberForceVelocityInverseDeGroote2016,
TendonForceLengthDeGroote2016,
TendonForceLengthInverseDeGroote2016,
)
from sympy.physics.biomechanics._mixin import _NamedMixin
from sympy.physics.mechanics.actuator import ForceActuator
from sympy.physics.vector.functions import dynamicsymbols
__all__ = [
'MusculotendonBase',
'MusculotendonDeGroote2016',
'MusculotendonFormulation',
]
@unique
class MusculotendonFormulation(IntEnum):
"""Enumeration of types of musculotendon dynamics formulations.
Explanation
===========
An (integer) enumeration is used as it allows for clearer selection of the
different formulations of musculotendon dynamics.
Members
=======
RIGID_TENDON : 0
A rigid tendon model.
FIBER_LENGTH_EXPLICIT : 1
An explicit elastic tendon model with the muscle fiber length (l_M) as
the state variable.
TENDON_FORCE_EXPLICIT : 2
An explicit elastic tendon model with the tendon force (F_T) as the
state variable.
FIBER_LENGTH_IMPLICIT : 3
An implicit elastic tendon model with the muscle fiber length (l_M) as
the state variable and the muscle fiber velocity as an additional input
variable.
TENDON_FORCE_IMPLICIT : 4
An implicit elastic tendon model with the tendon force (F_T) as the
state variable as the muscle fiber velocity as an additional input
variable.
"""
RIGID_TENDON = 0
FIBER_LENGTH_EXPLICIT = 1
TENDON_FORCE_EXPLICIT = 2
FIBER_LENGTH_IMPLICIT = 3
TENDON_FORCE_IMPLICIT = 4
def __str__(self):
"""Returns a string representation of the enumeration value.
Notes
=====
This hard coding is required due to an incompatibility between the
``IntEnum`` implementations in Python 3.10 and Python 3.11
(https://github.com/python/cpython/issues/84247). From Python 3.11
onwards, the ``__str__`` method uses ``int.__str__``, whereas prior it
used ``Enum.__str__``. Once Python 3.11 becomes the minimum version
supported by SymPy, this method override can be removed.
"""
return str(self.value)
_DEFAULT_MUSCULOTENDON_FORMULATION = MusculotendonFormulation.RIGID_TENDON
class MusculotendonBase(ForceActuator, _NamedMixin):
r"""Abstract base class for all musculotendon classes to inherit from.
Explanation
===========
A musculotendon generates a contractile force based on its activation,
length, and shortening velocity. This abstract base class is to be inherited
by all musculotendon subclasses that implement different characteristic
musculotendon curves. Characteristic musculotendon curves are required for
the tendon force-length, passive fiber force-length, active fiber force-
length, and fiber force-velocity relationships.
Parameters
==========
name : str
The name identifier associated with the musculotendon. This name is used
as a suffix when automatically generated symbols are instantiated. It
must be a string of nonzero length.
pathway : PathwayBase
The pathway that the actuator follows. This must be an instance of a
concrete subclass of ``PathwayBase``, e.g. ``LinearPathway``.
activation_dynamics : ActivationBase
The activation dynamics that will be modeled within the musculotendon.
This must be an instance of a concrete subclass of ``ActivationBase``,
e.g. ``FirstOrderActivationDeGroote2016``.
musculotendon_dynamics : MusculotendonFormulation | int
The formulation of musculotendon dynamics that should be used
internally, i.e. rigid or elastic tendon model, the choice of
musculotendon state etc. This must be a member of the integer
enumeration ``MusculotendonFormulation`` or an integer that can be cast
to a member. To use a rigid tendon formulation, set this to
``MusculotendonFormulation.RIGID_TENDON`` (or the integer value ``0``,
which will be cast to the enumeration member). There are four possible
formulations for an elastic tendon model. To use an explicit formulation
with the fiber length as the state, set this to
``MusculotendonFormulation.FIBER_LENGTH_EXPLICIT`` (or the integer value
``1``). To use an explicit formulation with the tendon force as the
state, set this to ``MusculotendonFormulation.TENDON_FORCE_EXPLICIT``
(or the integer value ``2``). To use an implicit formulation with the
fiber length as the state, set this to
``MusculotendonFormulation.FIBER_LENGTH_IMPLICIT`` (or the integer value
``3``). To use an implicit formulation with the tendon force as the
state, set this to ``MusculotendonFormulation.TENDON_FORCE_IMPLICIT``
(or the integer value ``4``). The default is
``MusculotendonFormulation.RIGID_TENDON``, which corresponds to a rigid
tendon formulation.
tendon_slack_length : Expr | None
The length of the tendon when the musculotendon is in its unloaded
state. In a rigid tendon model the tendon length is the tendon slack
length. In all musculotendon models, tendon slack length is used to
normalize tendon length to give
:math:`\tilde{l}^T = \frac{l^T}{l^T_{slack}}`.
peak_isometric_force : Expr | None
The maximum force that the muscle fiber can produce when it is
undergoing an isometric contraction (no lengthening velocity). In all
musculotendon models, peak isometric force is used to normalized tendon
and muscle fiber force to give
:math:`\tilde{F}^T = \frac{F^T}{F^M_{max}}`.
optimal_fiber_length : Expr | None
The muscle fiber length at which the muscle fibers produce no passive
force and their maximum active force. In all musculotendon models,
optimal fiber length is used to normalize muscle fiber length to give
:math:`\tilde{l}^M = \frac{l^M}{l^M_{opt}}`.
maximal_fiber_velocity : Expr | None
The fiber velocity at which, during muscle fiber shortening, the muscle
fibers are unable to produce any active force. In all musculotendon
models, maximal fiber velocity is used to normalize muscle fiber
extension velocity to give :math:`\tilde{v}^M = \frac{v^M}{v^M_{max}}`.
optimal_pennation_angle : Expr | None
The pennation angle when muscle fiber length equals the optimal fiber
length.
fiber_damping_coefficient : Expr | None
The coefficient of damping to be used in the damping element in the
muscle fiber model.
with_defaults : bool
Whether ``with_defaults`` alternate constructors should be used when
automatically constructing child classes. Default is ``False``.
"""
def __init__(
self,
name,
pathway,
activation_dynamics,
*,
musculotendon_dynamics=_DEFAULT_MUSCULOTENDON_FORMULATION,
tendon_slack_length=None,
peak_isometric_force=None,
optimal_fiber_length=None,
maximal_fiber_velocity=None,
optimal_pennation_angle=None,
fiber_damping_coefficient=None,
with_defaults=False,
):
self.name = name
# Supply a placeholder force to the super initializer, this will be
# replaced later
super().__init__(Symbol('F'), pathway)
# Activation dynamics
if not isinstance(activation_dynamics, ActivationBase):
msg = (
f'Can\'t set attribute `activation_dynamics` to '
f'{activation_dynamics} as it must be of type '
f'`ActivationBase`, not {type(activation_dynamics)}.'
)
raise TypeError(msg)
self._activation_dynamics = activation_dynamics
self._child_objects = (self._activation_dynamics, )
# Constants
if tendon_slack_length is not None:
self._l_T_slack = tendon_slack_length
else:
self._l_T_slack = Symbol(f'l_T_slack_{self.name}')
if peak_isometric_force is not None:
self._F_M_max = peak_isometric_force
else:
self._F_M_max = Symbol(f'F_M_max_{self.name}')
if optimal_fiber_length is not None:
self._l_M_opt = optimal_fiber_length
else:
self._l_M_opt = Symbol(f'l_M_opt_{self.name}')
if maximal_fiber_velocity is not None:
self._v_M_max = maximal_fiber_velocity
else:
self._v_M_max = Symbol(f'v_M_max_{self.name}')
if optimal_pennation_angle is not None:
self._alpha_opt = optimal_pennation_angle
else:
self._alpha_opt = Symbol(f'alpha_opt_{self.name}')
if fiber_damping_coefficient is not None:
self._beta = fiber_damping_coefficient
else:
self._beta = Symbol(f'beta_{self.name}')
# Musculotendon dynamics
self._with_defaults = with_defaults
if musculotendon_dynamics == MusculotendonFormulation.RIGID_TENDON:
self._rigid_tendon_musculotendon_dynamics()
elif musculotendon_dynamics == MusculotendonFormulation.FIBER_LENGTH_EXPLICIT:
self._fiber_length_explicit_musculotendon_dynamics()
elif musculotendon_dynamics == MusculotendonFormulation.TENDON_FORCE_EXPLICIT:
self._tendon_force_explicit_musculotendon_dynamics()
elif musculotendon_dynamics == MusculotendonFormulation.FIBER_LENGTH_IMPLICIT:
self._fiber_length_implicit_musculotendon_dynamics()
elif musculotendon_dynamics == MusculotendonFormulation.TENDON_FORCE_IMPLICIT:
self._tendon_force_implicit_musculotendon_dynamics()
else:
msg = (
f'Musculotendon dynamics {repr(musculotendon_dynamics)} '
f'passed to `musculotendon_dynamics` was of type '
f'{type(musculotendon_dynamics)}, must be '
f'{MusculotendonFormulation}.'
)
raise TypeError(msg)
self._musculotendon_dynamics = musculotendon_dynamics
# Must override the placeholder value in `self._force` now that the
# actual force has been calculated by
# `self._<MUSCULOTENDON FORMULATION>_musculotendon_dynamics`.
# Note that `self._force` assumes forces are expansile, musculotendon
# forces are contractile hence the minus sign preceeding `self._F_T`
# (the tendon force).
self._force = -self._F_T
@classmethod
def with_defaults(
cls,
name,
pathway,
activation_dynamics,
*,
musculotendon_dynamics=_DEFAULT_MUSCULOTENDON_FORMULATION,
tendon_slack_length=None,
peak_isometric_force=None,
optimal_fiber_length=None,
maximal_fiber_velocity=Float('10.0'),
optimal_pennation_angle=Float('0.0'),
fiber_damping_coefficient=Float('0.1'),
):
r"""Recommended constructor that will use the published constants.
Explanation
===========
Returns a new instance of the musculotendon class using recommended
values for ``v_M_max``, ``alpha_opt``, and ``beta``. The values are:
:math:`v^M_{max} = 10`
:math:`\alpha_{opt} = 0`
:math:`\beta = \frac{1}{10}`
The musculotendon curves are also instantiated using the constants from
the original publication.
Parameters
==========
name : str
The name identifier associated with the musculotendon. This name is
used as a suffix when automatically generated symbols are
instantiated. It must be a string of nonzero length.
pathway : PathwayBase
The pathway that the actuator follows. This must be an instance of a
concrete subclass of ``PathwayBase``, e.g. ``LinearPathway``.
activation_dynamics : ActivationBase
The activation dynamics that will be modeled within the
musculotendon. This must be an instance of a concrete subclass of
``ActivationBase``, e.g. ``FirstOrderActivationDeGroote2016``.
musculotendon_dynamics : MusculotendonFormulation | int
The formulation of musculotendon dynamics that should be used
internally, i.e. rigid or elastic tendon model, the choice of
musculotendon state etc. This must be a member of the integer
enumeration ``MusculotendonFormulation`` or an integer that can be
cast to a member. To use a rigid tendon formulation, set this to
``MusculotendonFormulation.RIGID_TENDON`` (or the integer value
``0``, which will be cast to the enumeration member). There are four
possible formulations for an elastic tendon model. To use an
explicit formulation with the fiber length as the state, set this to
``MusculotendonFormulation.FIBER_LENGTH_EXPLICIT`` (or the integer
value ``1``). To use an explicit formulation with the tendon force
as the state, set this to
``MusculotendonFormulation.TENDON_FORCE_EXPLICIT`` (or the integer
value ``2``). To use an implicit formulation with the fiber length
as the state, set this to
``MusculotendonFormulation.FIBER_LENGTH_IMPLICIT`` (or the integer
value ``3``). To use an implicit formulation with the tendon force
as the state, set this to
``MusculotendonFormulation.TENDON_FORCE_IMPLICIT`` (or the integer
value ``4``). The default is
``MusculotendonFormulation.RIGID_TENDON``, which corresponds to a
rigid tendon formulation.
tendon_slack_length : Expr | None
The length of the tendon when the musculotendon is in its unloaded
state. In a rigid tendon model the tendon length is the tendon slack
length. In all musculotendon models, tendon slack length is used to
normalize tendon length to give
:math:`\tilde{l}^T = \frac{l^T}{l^T_{slack}}`.
peak_isometric_force : Expr | None
The maximum force that the muscle fiber can produce when it is
undergoing an isometric contraction (no lengthening velocity). In
all musculotendon models, peak isometric force is used to normalized
tendon and muscle fiber force to give
:math:`\tilde{F}^T = \frac{F^T}{F^M_{max}}`.
optimal_fiber_length : Expr | None
The muscle fiber length at which the muscle fibers produce no
passive force and their maximum active force. In all musculotendon
models, optimal fiber length is used to normalize muscle fiber
length to give :math:`\tilde{l}^M = \frac{l^M}{l^M_{opt}}`.
maximal_fiber_velocity : Expr | None
The fiber velocity at which, during muscle fiber shortening, the
muscle fibers are unable to produce any active force. In all
musculotendon models, maximal fiber velocity is used to normalize
muscle fiber extension velocity to give
:math:`\tilde{v}^M = \frac{v^M}{v^M_{max}}`.
optimal_pennation_angle : Expr | None
The pennation angle when muscle fiber length equals the optimal
fiber length.
fiber_damping_coefficient : Expr | None
The coefficient of damping to be used in the damping element in the
muscle fiber model.
"""
return cls(
name,
pathway,
activation_dynamics=activation_dynamics,
musculotendon_dynamics=musculotendon_dynamics,
tendon_slack_length=tendon_slack_length,
peak_isometric_force=peak_isometric_force,
optimal_fiber_length=optimal_fiber_length,
maximal_fiber_velocity=maximal_fiber_velocity,
optimal_pennation_angle=optimal_pennation_angle,
fiber_damping_coefficient=fiber_damping_coefficient,
with_defaults=True,
)
@abstractmethod
def curves(cls):
"""Return a ``CharacteristicCurveCollection`` of the curves related to
the specific model."""
pass
@property
def tendon_slack_length(self):
r"""Symbol or value corresponding to the tendon slack length constant.
Explanation
===========
The length of the tendon when the musculotendon is in its unloaded
state. In a rigid tendon model the tendon length is the tendon slack
length. In all musculotendon models, tendon slack length is used to
normalize tendon length to give
:math:`\tilde{l}^T = \frac{l^T}{l^T_{slack}}`.
The alias ``l_T_slack`` can also be used to access the same attribute.
"""
return self._l_T_slack
@property
def l_T_slack(self):
r"""Symbol or value corresponding to the tendon slack length constant.
Explanation
===========
The length of the tendon when the musculotendon is in its unloaded
state. In a rigid tendon model the tendon length is the tendon slack
length. In all musculotendon models, tendon slack length is used to
normalize tendon length to give
:math:`\tilde{l}^T = \frac{l^T}{l^T_{slack}}`.
The alias ``tendon_slack_length`` can also be used to access the same
attribute.
"""
return self._l_T_slack
@property
def peak_isometric_force(self):
r"""Symbol or value corresponding to the peak isometric force constant.
Explanation
===========
The maximum force that the muscle fiber can produce when it is
undergoing an isometric contraction (no lengthening velocity). In all
musculotendon models, peak isometric force is used to normalized tendon
and muscle fiber force to give
:math:`\tilde{F}^T = \frac{F^T}{F^M_{max}}`.
The alias ``F_M_max`` can also be used to access the same attribute.
"""
return self._F_M_max
@property
def F_M_max(self):
r"""Symbol or value corresponding to the peak isometric force constant.
Explanation
===========
The maximum force that the muscle fiber can produce when it is
undergoing an isometric contraction (no lengthening velocity). In all
musculotendon models, peak isometric force is used to normalized tendon
and muscle fiber force to give
:math:`\tilde{F}^T = \frac{F^T}{F^M_{max}}`.
The alias ``peak_isometric_force`` can also be used to access the same
attribute.
"""
return self._F_M_max
@property
def optimal_fiber_length(self):
r"""Symbol or value corresponding to the optimal fiber length constant.
Explanation
===========
The muscle fiber length at which the muscle fibers produce no passive
force and their maximum active force. In all musculotendon models,
optimal fiber length is used to normalize muscle fiber length to give
:math:`\tilde{l}^M = \frac{l^M}{l^M_{opt}}`.
The alias ``l_M_opt`` can also be used to access the same attribute.
"""
return self._l_M_opt
@property
def l_M_opt(self):
r"""Symbol or value corresponding to the optimal fiber length constant.
Explanation
===========
The muscle fiber length at which the muscle fibers produce no passive
force and their maximum active force. In all musculotendon models,
optimal fiber length is used to normalize muscle fiber length to give
:math:`\tilde{l}^M = \frac{l^M}{l^M_{opt}}`.
The alias ``optimal_fiber_length`` can also be used to access the same
attribute.
"""
return self._l_M_opt
@property
def maximal_fiber_velocity(self):
r"""Symbol or value corresponding to the maximal fiber velocity constant.
Explanation
===========
The fiber velocity at which, during muscle fiber shortening, the muscle
fibers are unable to produce any active force. In all musculotendon
models, maximal fiber velocity is used to normalize muscle fiber
extension velocity to give :math:`\tilde{v}^M = \frac{v^M}{v^M_{max}}`.
The alias ``v_M_max`` can also be used to access the same attribute.
"""
return self._v_M_max
@property
def v_M_max(self):
r"""Symbol or value corresponding to the maximal fiber velocity constant.
Explanation
===========
The fiber velocity at which, during muscle fiber shortening, the muscle
fibers are unable to produce any active force. In all musculotendon
models, maximal fiber velocity is used to normalize muscle fiber
extension velocity to give :math:`\tilde{v}^M = \frac{v^M}{v^M_{max}}`.
The alias ``maximal_fiber_velocity`` can also be used to access the same
attribute.
"""
return self._v_M_max
@property
def optimal_pennation_angle(self):
"""Symbol or value corresponding to the optimal pennation angle
constant.
Explanation
===========
The pennation angle when muscle fiber length equals the optimal fiber
length.
The alias ``alpha_opt`` can also be used to access the same attribute.
"""
return self._alpha_opt
@property
def alpha_opt(self):
"""Symbol or value corresponding to the optimal pennation angle
constant.
Explanation
===========
The pennation angle when muscle fiber length equals the optimal fiber
length.
The alias ``optimal_pennation_angle`` can also be used to access the
same attribute.
"""
return self._alpha_opt
@property
def fiber_damping_coefficient(self):
"""Symbol or value corresponding to the fiber damping coefficient
constant.
Explanation
===========
The coefficient of damping to be used in the damping element in the
muscle fiber model.
The alias ``beta`` can also be used to access the same attribute.
"""
return self._beta
@property
def beta(self):
"""Symbol or value corresponding to the fiber damping coefficient
constant.
Explanation
===========
The coefficient of damping to be used in the damping element in the
muscle fiber model.
The alias ``fiber_damping_coefficient`` can also be used to access the
same attribute.
"""
return self._beta
@property
def activation_dynamics(self):
"""Activation dynamics model governing this musculotendon's activation.
Explanation
===========
Returns the instance of a subclass of ``ActivationBase`` that governs
the relationship between excitation and activation that is used to
represent the activation dynamics of this musculotendon.
"""
return self._activation_dynamics
@property
def excitation(self):
"""Dynamic symbol representing excitation.
Explanation
===========
The alias ``e`` can also be used to access the same attribute.
"""
return self._activation_dynamics._e
@property
def e(self):
"""Dynamic symbol representing excitation.
Explanation
===========
The alias ``excitation`` can also be used to access the same attribute.
"""
return self._activation_dynamics._e
@property
def activation(self):
"""Dynamic symbol representing activation.
Explanation
===========
The alias ``a`` can also be used to access the same attribute.
"""
return self._activation_dynamics._a
@property
def a(self):
"""Dynamic symbol representing activation.
Explanation
===========
The alias ``activation`` can also be used to access the same attribute.
"""
return self._activation_dynamics._a
@property
def musculotendon_dynamics(self):
"""The choice of rigid or type of elastic tendon musculotendon dynamics.
Explanation
===========
The formulation of musculotendon dynamics that should be used
internally, i.e. rigid or elastic tendon model, the choice of
musculotendon state etc. This must be a member of the integer
enumeration ``MusculotendonFormulation`` or an integer that can be cast
to a member. To use a rigid tendon formulation, set this to
``MusculotendonFormulation.RIGID_TENDON`` (or the integer value ``0``,
which will be cast to the enumeration member). There are four possible
formulations for an elastic tendon model. To use an explicit formulation
with the fiber length as the state, set this to
``MusculotendonFormulation.FIBER_LENGTH_EXPLICIT`` (or the integer value
``1``). To use an explicit formulation with the tendon force as the
state, set this to ``MusculotendonFormulation.TENDON_FORCE_EXPLICIT``
(or the integer value ``2``). To use an implicit formulation with the
fiber length as the state, set this to
``MusculotendonFormulation.FIBER_LENGTH_IMPLICIT`` (or the integer value
``3``). To use an implicit formulation with the tendon force as the
state, set this to ``MusculotendonFormulation.TENDON_FORCE_IMPLICIT``
(or the integer value ``4``). The default is
``MusculotendonFormulation.RIGID_TENDON``, which corresponds to a rigid
tendon formulation.
"""
return self._musculotendon_dynamics
def _rigid_tendon_musculotendon_dynamics(self):
"""Rigid tendon musculotendon."""
self._l_MT = self.pathway.length
self._v_MT = self.pathway.extension_velocity
self._l_T = self._l_T_slack
self._l_T_tilde = Integer(1)
self._l_M = sqrt((self._l_MT - self._l_T)**2 + (self._l_M_opt*sin(self._alpha_opt))**2)
self._l_M_tilde = self._l_M/self._l_M_opt
self._v_M = self._v_MT*(self._l_MT - self._l_T_slack)/self._l_M
self._v_M_tilde = self._v_M/self._v_M_max
if self._with_defaults:
self._fl_T = self.curves.tendon_force_length.with_defaults(self._l_T_tilde)
self._fl_M_pas = self.curves.fiber_force_length_passive.with_defaults(self._l_M_tilde)
self._fl_M_act = self.curves.fiber_force_length_active.with_defaults(self._l_M_tilde)
self._fv_M = self.curves.fiber_force_velocity.with_defaults(self._v_M_tilde)
else:
fl_T_constants = symbols(f'c_0:4_fl_T_{self.name}')
self._fl_T = self.curves.tendon_force_length(self._l_T_tilde, *fl_T_constants)
fl_M_pas_constants = symbols(f'c_0:2_fl_M_pas_{self.name}')
self._fl_M_pas = self.curves.fiber_force_length_passive(self._l_M_tilde, *fl_M_pas_constants)
fl_M_act_constants = symbols(f'c_0:12_fl_M_act_{self.name}')
self._fl_M_act = self.curves.fiber_force_length_active(self._l_M_tilde, *fl_M_act_constants)
fv_M_constants = symbols(f'c_0:4_fv_M_{self.name}')
self._fv_M = self.curves.fiber_force_velocity(self._v_M_tilde, *fv_M_constants)
self._F_M_tilde = self.a*self._fl_M_act*self._fv_M + self._fl_M_pas + self._beta*self._v_M_tilde
self._F_T_tilde = self._F_M_tilde
self._F_M = self._F_M_tilde*self._F_M_max
self._cos_alpha = cos(self._alpha_opt)
self._F_T = self._F_M*self._cos_alpha
# Containers
self._state_vars = zeros(0, 1)
self._input_vars = zeros(0, 1)
self._state_eqns = zeros(0, 1)
self._curve_constants = Matrix(
fl_T_constants
+ fl_M_pas_constants
+ fl_M_act_constants
+ fv_M_constants
) if not self._with_defaults else zeros(0, 1)
def _fiber_length_explicit_musculotendon_dynamics(self):
"""Elastic tendon musculotendon using `l_M_tilde` as a state."""
self._l_M_tilde = dynamicsymbols(f'l_M_tilde_{self.name}')
self._l_MT = self.pathway.length
self._v_MT = self.pathway.extension_velocity
self._l_M = self._l_M_tilde*self._l_M_opt
self._l_T = self._l_MT - sqrt(self._l_M**2 - (self._l_M_opt*sin(self._alpha_opt))**2)
self._l_T_tilde = self._l_T/self._l_T_slack
self._cos_alpha = (self._l_MT - self._l_T)/self._l_M
if self._with_defaults:
self._fl_T = self.curves.tendon_force_length.with_defaults(self._l_T_tilde)
self._fl_M_pas = self.curves.fiber_force_length_passive.with_defaults(self._l_M_tilde)
self._fl_M_act = self.curves.fiber_force_length_active.with_defaults(self._l_M_tilde)
else:
fl_T_constants = symbols(f'c_0:4_fl_T_{self.name}')
self._fl_T = self.curves.tendon_force_length(self._l_T_tilde, *fl_T_constants)
fl_M_pas_constants = symbols(f'c_0:2_fl_M_pas_{self.name}')
self._fl_M_pas = self.curves.fiber_force_length_passive(self._l_M_tilde, *fl_M_pas_constants)
fl_M_act_constants = symbols(f'c_0:12_fl_M_act_{self.name}')
self._fl_M_act = self.curves.fiber_force_length_active(self._l_M_tilde, *fl_M_act_constants)
self._F_T_tilde = self._fl_T
self._F_T = self._F_T_tilde*self._F_M_max
self._F_M = self._F_T/self._cos_alpha
self._F_M_tilde = self._F_M/self._F_M_max
self._fv_M = (self._F_M_tilde - self._fl_M_pas)/(self.a*self._fl_M_act)
if self._with_defaults:
self._v_M_tilde = self.curves.fiber_force_velocity_inverse.with_defaults(self._fv_M)
else:
fv_M_constants = symbols(f'c_0:4_fv_M_{self.name}')
self._v_M_tilde = self.curves.fiber_force_velocity_inverse(self._fv_M, *fv_M_constants)
self._dl_M_tilde_dt = (self._v_M_max/self._l_M_opt)*self._v_M_tilde
self._state_vars = Matrix([self._l_M_tilde])
self._input_vars = zeros(0, 1)
self._state_eqns = Matrix([self._dl_M_tilde_dt])
self._curve_constants = Matrix(
fl_T_constants
+ fl_M_pas_constants
+ fl_M_act_constants
+ fv_M_constants
) if not self._with_defaults else zeros(0, 1)
def _tendon_force_explicit_musculotendon_dynamics(self):
"""Elastic tendon musculotendon using `F_T_tilde` as a state."""
self._F_T_tilde = dynamicsymbols(f'F_T_tilde_{self.name}')
self._l_MT = self.pathway.length
self._v_MT = self.pathway.extension_velocity
self._fl_T = self._F_T_tilde
if self._with_defaults:
self._fl_T_inv = self.curves.tendon_force_length_inverse.with_defaults(self._fl_T)
else:
fl_T_constants = symbols(f'c_0:4_fl_T_{self.name}')
self._fl_T_inv = self.curves.tendon_force_length_inverse(self._fl_T, *fl_T_constants)
self._l_T_tilde = self._fl_T_inv
self._l_T = self._l_T_tilde*self._l_T_slack
self._l_M = sqrt((self._l_MT - self._l_T)**2 + (self._l_M_opt*sin(self._alpha_opt))**2)
self._l_M_tilde = self._l_M/self._l_M_opt
if self._with_defaults:
self._fl_M_pas = self.curves.fiber_force_length_passive.with_defaults(self._l_M_tilde)
self._fl_M_act = self.curves.fiber_force_length_active.with_defaults(self._l_M_tilde)
else:
fl_M_pas_constants = symbols(f'c_0:2_fl_M_pas_{self.name}')
self._fl_M_pas = self.curves.fiber_force_length_passive(self._l_M_tilde, *fl_M_pas_constants)
fl_M_act_constants = symbols(f'c_0:12_fl_M_act_{self.name}')
self._fl_M_act = self.curves.fiber_force_length_active(self._l_M_tilde, *fl_M_act_constants)
self._cos_alpha = (self._l_MT - self._l_T)/self._l_M
self._F_T = self._F_T_tilde*self._F_M_max
self._F_M = self._F_T/self._cos_alpha
self._F_M_tilde = self._F_M/self._F_M_max
self._fv_M = (self._F_M_tilde - self._fl_M_pas)/(self.a*self._fl_M_act)
if self._with_defaults:
self._fv_M_inv = self.curves.fiber_force_velocity_inverse.with_defaults(self._fv_M)
else:
fv_M_constants = symbols(f'c_0:4_fv_M_{self.name}')
self._fv_M_inv = self.curves.fiber_force_velocity_inverse(self._fv_M, *fv_M_constants)
self._v_M_tilde = self._fv_M_inv
self._v_M = self._v_M_tilde*self._v_M_max
self._v_T = self._v_MT - (self._v_M/self._cos_alpha)
self._v_T_tilde = self._v_T/self._l_T_slack
if self._with_defaults:
self._fl_T = self.curves.tendon_force_length.with_defaults(self._l_T_tilde)
else:
self._fl_T = self.curves.tendon_force_length(self._l_T_tilde, *fl_T_constants)
self._dF_T_tilde_dt = self._fl_T.diff(dynamicsymbols._t).subs({self._l_T_tilde.diff(dynamicsymbols._t): self._v_T_tilde})
self._state_vars = Matrix([self._F_T_tilde])
self._input_vars = zeros(0, 1)
self._state_eqns = Matrix([self._dF_T_tilde_dt])
self._curve_constants = Matrix(
fl_T_constants
+ fl_M_pas_constants
+ fl_M_act_constants
+ fv_M_constants
) if not self._with_defaults else zeros(0, 1)
def _fiber_length_implicit_musculotendon_dynamics(self):
raise NotImplementedError
def _tendon_force_implicit_musculotendon_dynamics(self):
raise NotImplementedError
@property
def state_vars(self):
"""Ordered column matrix of functions of time that represent the state
variables.
Explanation
===========
The alias ``x`` can also be used to access the same attribute.
"""
state_vars = [self._state_vars]
for child in self._child_objects:
state_vars.append(child.state_vars)
return Matrix.vstack(*state_vars)
@property
def x(self):
"""Ordered column matrix of functions of time that represent the state
variables.
Explanation
===========
The alias ``state_vars`` can also be used to access the same attribute.
"""
state_vars = [self._state_vars]
for child in self._child_objects:
state_vars.append(child.state_vars)
return Matrix.vstack(*state_vars)
@property
def input_vars(self):
"""Ordered column matrix of functions of time that represent the input
variables.
Explanation
===========
The alias ``r`` can also be used to access the same attribute.
"""
input_vars = [self._input_vars]
for child in self._child_objects:
input_vars.append(child.input_vars)
return Matrix.vstack(*input_vars)
@property
def r(self):
"""Ordered column matrix of functions of time that represent the input
variables.
Explanation
===========
The alias ``input_vars`` can also be used to access the same attribute.
"""
input_vars = [self._input_vars]
for child in self._child_objects:
input_vars.append(child.input_vars)
return Matrix.vstack(*input_vars)
@property
def constants(self):
"""Ordered column matrix of non-time varying symbols present in ``M``
and ``F``.
Explanation
===========
Only symbolic constants are returned. If a numeric type (e.g. ``Float``)
has been used instead of ``Symbol`` for a constant then that attribute
will not be included in the matrix returned by this property. This is
because the primary use of this property attribute is to provide an
ordered sequence of the still-free symbols that require numeric values
during code generation.
The alias ``p`` can also be used to access the same attribute.
"""
musculotendon_constants = [
self._l_T_slack,
self._F_M_max,
self._l_M_opt,
self._v_M_max,
self._alpha_opt,
self._beta,
]
musculotendon_constants = [
c for c in musculotendon_constants if not c.is_number
]
constants = [
Matrix(musculotendon_constants)
if musculotendon_constants
else zeros(0, 1)
]
for child in self._child_objects:
constants.append(child.constants)
constants.append(self._curve_constants)
return Matrix.vstack(*constants)
@property
def p(self):
"""Ordered column matrix of non-time varying symbols present in ``M``
and ``F``.
Explanation
===========
Only symbolic constants are returned. If a numeric type (e.g. ``Float``)
has been used instead of ``Symbol`` for a constant then that attribute
will not be included in the matrix returned by this property. This is
because the primary use of this property attribute is to provide an
ordered sequence of the still-free symbols that require numeric values
during code generation.
The alias ``constants`` can also be used to access the same attribute.
"""
musculotendon_constants = [
self._l_T_slack,
self._F_M_max,
self._l_M_opt,
self._v_M_max,
self._alpha_opt,
self._beta,
]
musculotendon_constants = [
c for c in musculotendon_constants if not c.is_number
]
constants = [
Matrix(musculotendon_constants)
if musculotendon_constants
else zeros(0, 1)
]
for child in self._child_objects:
constants.append(child.constants)
constants.append(self._curve_constants)
return Matrix.vstack(*constants)
@property
def M(self):
"""Ordered square matrix of coefficients on the LHS of ``M x' = F``.
Explanation
===========
The square matrix that forms part of the LHS of the linear system of
ordinary differential equations governing the activation dynamics:
``M(x, r, t, p) x' = F(x, r, t, p)``.
As zeroth-order activation dynamics have no state variables, this
linear system has dimension 0 and therefore ``M`` is an empty square
``Matrix`` with shape (0, 0).
"""
M = [eye(len(self._state_vars))]
for child in self._child_objects:
M.append(child.M)
return diag(*M)
@property
def F(self):
"""Ordered column matrix of equations on the RHS of ``M x' = F``.
Explanation
===========
The column matrix that forms the RHS of the linear system of ordinary
differential equations governing the activation dynamics:
``M(x, r, t, p) x' = F(x, r, t, p)``.
As zeroth-order activation dynamics have no state variables, this
linear system has dimension 0 and therefore ``F`` is an empty column
``Matrix`` with shape (0, 1).
"""
F = [self._state_eqns]
for child in self._child_objects:
F.append(child.F)
return Matrix.vstack(*F)
def rhs(self):
"""Ordered column matrix of equations for the solution of ``M x' = F``.
Explanation
===========
The solution to the linear system of ordinary differential equations
governing the activation dynamics:
``M(x, r, t, p) x' = F(x, r, t, p)``.
As zeroth-order activation dynamics have no state variables, this
linear has dimension 0 and therefore this method returns an empty
column ``Matrix`` with shape (0, 1).
"""
is_explicit = (
MusculotendonFormulation.FIBER_LENGTH_EXPLICIT,
MusculotendonFormulation.TENDON_FORCE_EXPLICIT,
)
if self.musculotendon_dynamics is MusculotendonFormulation.RIGID_TENDON:
child_rhs = [child.rhs() for child in self._child_objects]
return Matrix.vstack(*child_rhs)
elif self.musculotendon_dynamics in is_explicit:
rhs = self._state_eqns
child_rhs = [child.rhs() for child in self._child_objects]
return Matrix.vstack(rhs, *child_rhs)
return self.M.solve(self.F)
def __repr__(self):
"""Returns a string representation to reinstantiate the model."""
return (
f'{self.__class__.__name__}({self.name!r}, '
f'pathway={self.pathway!r}, '
f'activation_dynamics={self.activation_dynamics!r}, '
f'musculotendon_dynamics={self.musculotendon_dynamics}, '
f'tendon_slack_length={self._l_T_slack!r}, '
f'peak_isometric_force={self._F_M_max!r}, '
f'optimal_fiber_length={self._l_M_opt!r}, '
f'maximal_fiber_velocity={self._v_M_max!r}, '
f'optimal_pennation_angle={self._alpha_opt!r}, '
f'fiber_damping_coefficient={self._beta!r})'
)
def __str__(self):
"""Returns a string representation of the expression for musculotendon
force."""
return str(self.force)
class MusculotendonDeGroote2016(MusculotendonBase):
r"""Musculotendon model using the curves of De Groote et al., 2016 [1]_.
Examples
========
This class models the musculotendon actuator parametrized by the
characteristic curves described in De Groote et al., 2016 [1]_. Like all
musculotendon models in SymPy's biomechanics module, it requires a pathway
to define its line of action. We'll begin by creating a simple
``LinearPathway`` between two points that our musculotendon will follow.
We'll create a point ``O`` to represent the musculotendon's origin and
another ``I`` to represent its insertion.
>>> from sympy import symbols
>>> from sympy.physics.mechanics import (LinearPathway, Point,
... ReferenceFrame, dynamicsymbols)
>>> N = ReferenceFrame('N')
>>> O, I = O, P = symbols('O, I', cls=Point)
>>> q, u = dynamicsymbols('q, u', real=True)
>>> I.set_pos(O, q*N.x)
>>> O.set_vel(N, 0)
>>> I.set_vel(N, u*N.x)
>>> pathway = LinearPathway(O, I)
>>> pathway.attachments
(O, I)
>>> pathway.length
Abs(q(t))
>>> pathway.extension_velocity
sign(q(t))*Derivative(q(t), t)
A musculotendon also takes an instance of an activation dynamics model as
this will be used to provide symbols for the activation in the formulation
of the musculotendon dynamics. We'll use an instance of
``FirstOrderActivationDeGroote2016`` to represent first-order activation
dynamics. Note that a single name argument needs to be provided as SymPy
will use this as a suffix.
>>> from sympy.physics.biomechanics import FirstOrderActivationDeGroote2016
>>> activation = FirstOrderActivationDeGroote2016('muscle')
>>> activation.x
Matrix([[a_muscle(t)]])
>>> activation.r
Matrix([[e_muscle(t)]])
>>> activation.p
Matrix([
[tau_a_muscle],
[tau_d_muscle],
[ b_muscle]])
>>> activation.rhs()
Matrix([[((1/2 - tanh(b_muscle*(-a_muscle(t) + e_muscle(t)))/2)*(3*...]])
The musculotendon class requires symbols or values to be passed to represent
the constants in the musculotendon dynamics. We'll use SymPy's ``symbols``
function to create symbols for the maximum isometric force ``F_M_max``,
optimal fiber length ``l_M_opt``, tendon slack length ``l_T_slack``, maximum
fiber velocity ``v_M_max``, optimal pennation angle ``alpha_opt, and fiber
damping coefficient ``beta``.
>>> F_M_max = symbols('F_M_max', real=True)
>>> l_M_opt = symbols('l_M_opt', real=True)
>>> l_T_slack = symbols('l_T_slack', real=True)
>>> v_M_max = symbols('v_M_max', real=True)
>>> alpha_opt = symbols('alpha_opt', real=True)
>>> beta = symbols('beta', real=True)
We can then import the class ``MusculotendonDeGroote2016`` from the
biomechanics module and create an instance by passing in the various objects
we have previously instantiated. By default, a musculotendon model with
rigid tendon musculotendon dynamics will be created.
>>> from sympy.physics.biomechanics import MusculotendonDeGroote2016
>>> rigid_tendon_muscle = MusculotendonDeGroote2016(
... 'muscle',
... pathway,
... activation,
... tendon_slack_length=l_T_slack,
... peak_isometric_force=F_M_max,
... optimal_fiber_length=l_M_opt,
... maximal_fiber_velocity=v_M_max,
... optimal_pennation_angle=alpha_opt,
... fiber_damping_coefficient=beta,
... )
We can inspect the various properties of the musculotendon, including
getting the symbolic expression describing the force it produces using its
``force`` attribute.
>>> rigid_tendon_muscle.force
-F_M_max*(beta*(-l_T_slack + Abs(q(t)))*sign(q(t))*Derivative(q(t), t)...
When we created the musculotendon object, we passed in an instance of an
activation dynamics object that governs the activation within the
musculotendon. SymPy makes a design choice here that the activation dynamics
instance will be treated as a child object of the musculotendon dynamics.
Therefore, if we want to inspect the state and input variables associated
with the musculotendon model, we will also be returned the state and input
variables associated with the child object, or the activation dynamics in
this case. As the musculotendon model that we created here uses rigid tendon
dynamics, no additional states or inputs relating to the musculotendon are
introduces. Consequently, the model has a single state associated with it,
the activation, and a single input associated with it, the excitation. The
states and inputs can be inspected using the ``x`` and ``r`` attributes
respectively. Note that both ``x`` and ``r`` have the alias attributes of
``state_vars`` and ``input_vars``.
>>> rigid_tendon_muscle.x
Matrix([[a_muscle(t)]])
>>> rigid_tendon_muscle.r
Matrix([[e_muscle(t)]])
To see which constants are symbolic in the musculotendon model, we can use
the ``p`` or ``constants`` attribute. This returns a ``Matrix`` populated
by the constants that are represented by a ``Symbol`` rather than a numeric
value.
>>> rigid_tendon_muscle.p
Matrix([
[ l_T_slack],
[ F_M_max],
[ l_M_opt],
[ v_M_max],
[ alpha_opt],
[ beta],
[ tau_a_muscle],
[ tau_d_muscle],
[ b_muscle],
[ c_0_fl_T_muscle],
[ c_1_fl_T_muscle],
[ c_2_fl_T_muscle],
[ c_3_fl_T_muscle],
[ c_0_fl_M_pas_muscle],
[ c_1_fl_M_pas_muscle],
[ c_0_fl_M_act_muscle],
[ c_1_fl_M_act_muscle],
[ c_2_fl_M_act_muscle],
[ c_3_fl_M_act_muscle],
[ c_4_fl_M_act_muscle],
[ c_5_fl_M_act_muscle],
[ c_6_fl_M_act_muscle],
[ c_7_fl_M_act_muscle],
[ c_8_fl_M_act_muscle],
[ c_9_fl_M_act_muscle],
[c_10_fl_M_act_muscle],
[c_11_fl_M_act_muscle],
[ c_0_fv_M_muscle],
[ c_1_fv_M_muscle],
[ c_2_fv_M_muscle],
[ c_3_fv_M_muscle]])
Finally, we can call the ``rhs`` method to return a ``Matrix`` that
contains as its elements the righthand side of the ordinary differential
equations corresponding to each of the musculotendon's states. Like the
method with the same name on the ``Method`` classes in SymPy's mechanics
module, this returns a column vector where the number of rows corresponds to
the number of states. For our example here, we have a single state, the
dynamic symbol ``a_muscle(t)``, so the returned value is a 1-by-1
``Matrix``.
>>> rigid_tendon_muscle.rhs()
Matrix([[((1/2 - tanh(b_muscle*(-a_muscle(t) + e_muscle(t)))/2)*(3*...]])
The musculotendon class supports elastic tendon musculotendon models in
addition to rigid tendon ones. You can choose to either use the fiber length
or tendon force as an additional state. You can also specify whether an
explicit or implicit formulation should be used. To select a formulation,
pass a member of the ``MusculotendonFormulation`` enumeration to the
``musculotendon_dynamics`` parameter when calling the constructor. This
enumeration is an ``IntEnum``, so you can also pass an integer, however it
is recommended to use the enumeration as it is clearer which formulation you
are actually selecting. Below, we'll use the ``FIBER_LENGTH_EXPLICIT``
member to create a musculotendon with an elastic tendon that will use the
(normalized) muscle fiber length as an additional state and will produce
the governing ordinary differential equation in explicit form.
>>> from sympy.physics.biomechanics import MusculotendonFormulation
>>> elastic_tendon_muscle = MusculotendonDeGroote2016(
... 'muscle',
... pathway,
... activation,
... musculotendon_dynamics=MusculotendonFormulation.FIBER_LENGTH_EXPLICIT,
... tendon_slack_length=l_T_slack,
... peak_isometric_force=F_M_max,
... optimal_fiber_length=l_M_opt,
... maximal_fiber_velocity=v_M_max,
... optimal_pennation_angle=alpha_opt,
... fiber_damping_coefficient=beta,
... )
>>> elastic_tendon_muscle.force
-F_M_max*TendonForceLengthDeGroote2016((-sqrt(l_M_opt**2*...
>>> elastic_tendon_muscle.x
Matrix([
[l_M_tilde_muscle(t)],
[ a_muscle(t)]])
>>> elastic_tendon_muscle.r
Matrix([[e_muscle(t)]])
>>> elastic_tendon_muscle.p
Matrix([
[ l_T_slack],
[ F_M_max],
[ l_M_opt],
[ v_M_max],
[ alpha_opt],
[ beta],
[ tau_a_muscle],
[ tau_d_muscle],
[ b_muscle],
[ c_0_fl_T_muscle],
[ c_1_fl_T_muscle],
[ c_2_fl_T_muscle],
[ c_3_fl_T_muscle],
[ c_0_fl_M_pas_muscle],
[ c_1_fl_M_pas_muscle],
[ c_0_fl_M_act_muscle],
[ c_1_fl_M_act_muscle],
[ c_2_fl_M_act_muscle],
[ c_3_fl_M_act_muscle],
[ c_4_fl_M_act_muscle],
[ c_5_fl_M_act_muscle],
[ c_6_fl_M_act_muscle],
[ c_7_fl_M_act_muscle],
[ c_8_fl_M_act_muscle],
[ c_9_fl_M_act_muscle],
[c_10_fl_M_act_muscle],
[c_11_fl_M_act_muscle],
[ c_0_fv_M_muscle],
[ c_1_fv_M_muscle],
[ c_2_fv_M_muscle],
[ c_3_fv_M_muscle]])
>>> elastic_tendon_muscle.rhs()
Matrix([
[v_M_max*FiberForceVelocityInverseDeGroote2016((l_M_opt*...],
[ ((1/2 - tanh(b_muscle*(-a_muscle(t) + e_muscle(t)))/2)*(3*...]])
It is strongly recommended to use the alternate ``with_defaults``
constructor when creating an instance because this will ensure that the
published constants are used in the musculotendon characteristic curves.
>>> elastic_tendon_muscle = MusculotendonDeGroote2016.with_defaults(
... 'muscle',
... pathway,
... activation,
... musculotendon_dynamics=MusculotendonFormulation.FIBER_LENGTH_EXPLICIT,
... tendon_slack_length=l_T_slack,
... peak_isometric_force=F_M_max,
... optimal_fiber_length=l_M_opt,
... )
>>> elastic_tendon_muscle.x
Matrix([
[l_M_tilde_muscle(t)],
[ a_muscle(t)]])
>>> elastic_tendon_muscle.r
Matrix([[e_muscle(t)]])
>>> elastic_tendon_muscle.p
Matrix([
[ l_T_slack],
[ F_M_max],
[ l_M_opt],
[tau_a_muscle],
[tau_d_muscle],
[ b_muscle]])
Parameters
==========
name : str
The name identifier associated with the musculotendon. This name is used
as a suffix when automatically generated symbols are instantiated. It
must be a string of nonzero length.
pathway : PathwayBase
The pathway that the actuator follows. This must be an instance of a
concrete subclass of ``PathwayBase``, e.g. ``LinearPathway``.
activation_dynamics : ActivationBase
The activation dynamics that will be modeled within the musculotendon.
This must be an instance of a concrete subclass of ``ActivationBase``,
e.g. ``FirstOrderActivationDeGroote2016``.
musculotendon_dynamics : MusculotendonFormulation | int
The formulation of musculotendon dynamics that should be used
internally, i.e. rigid or elastic tendon model, the choice of
musculotendon state etc. This must be a member of the integer
enumeration ``MusculotendonFormulation`` or an integer that can be cast
to a member. To use a rigid tendon formulation, set this to
``MusculotendonFormulation.RIGID_TENDON`` (or the integer value ``0``,
which will be cast to the enumeration member). There are four possible
formulations for an elastic tendon model. To use an explicit formulation
with the fiber length as the state, set this to
``MusculotendonFormulation.FIBER_LENGTH_EXPLICIT`` (or the integer value
``1``). To use an explicit formulation with the tendon force as the
state, set this to ``MusculotendonFormulation.TENDON_FORCE_EXPLICIT``
(or the integer value ``2``). To use an implicit formulation with the
fiber length as the state, set this to
``MusculotendonFormulation.FIBER_LENGTH_IMPLICIT`` (or the integer value
``3``). To use an implicit formulation with the tendon force as the
state, set this to ``MusculotendonFormulation.TENDON_FORCE_IMPLICIT``
(or the integer value ``4``). The default is
``MusculotendonFormulation.RIGID_TENDON``, which corresponds to a rigid
tendon formulation.
tendon_slack_length : Expr | None
The length of the tendon when the musculotendon is in its unloaded
state. In a rigid tendon model the tendon length is the tendon slack
length. In all musculotendon models, tendon slack length is used to
normalize tendon length to give
:math:`\tilde{l}^T = \frac{l^T}{l^T_{slack}}`.
peak_isometric_force : Expr | None
The maximum force that the muscle fiber can produce when it is
undergoing an isometric contraction (no lengthening velocity). In all
musculotendon models, peak isometric force is used to normalized tendon
and muscle fiber force to give
:math:`\tilde{F}^T = \frac{F^T}{F^M_{max}}`.
optimal_fiber_length : Expr | None
The muscle fiber length at which the muscle fibers produce no passive
force and their maximum active force. In all musculotendon models,
optimal fiber length is used to normalize muscle fiber length to give
:math:`\tilde{l}^M = \frac{l^M}{l^M_{opt}}`.
maximal_fiber_velocity : Expr | None
The fiber velocity at which, during muscle fiber shortening, the muscle
fibers are unable to produce any active force. In all musculotendon
models, maximal fiber velocity is used to normalize muscle fiber
extension velocity to give :math:`\tilde{v}^M = \frac{v^M}{v^M_{max}}`.
optimal_pennation_angle : Expr | None
The pennation angle when muscle fiber length equals the optimal fiber
length.
fiber_damping_coefficient : Expr | None
The coefficient of damping to be used in the damping element in the
muscle fiber model.
with_defaults : bool
Whether ``with_defaults`` alternate constructors should be used when
automatically constructing child classes. Default is ``False``.
References
==========
.. [1] De Groote, F., Kinney, A. L., Rao, A. V., & Fregly, B. J., Evaluation
of direct collocation optimal control problem formulations for
solving the muscle redundancy problem, Annals of biomedical
engineering, 44(10), (2016) pp. 2922-2936
"""
curves = CharacteristicCurveCollection(
tendon_force_length=TendonForceLengthDeGroote2016,
tendon_force_length_inverse=TendonForceLengthInverseDeGroote2016,
fiber_force_length_passive=FiberForceLengthPassiveDeGroote2016,
fiber_force_length_passive_inverse=FiberForceLengthPassiveInverseDeGroote2016,
fiber_force_length_active=FiberForceLengthActiveDeGroote2016,
fiber_force_velocity=FiberForceVelocityDeGroote2016,
fiber_force_velocity_inverse=FiberForceVelocityInverseDeGroote2016,
)
PK ]ZZZ�� �{ { - sympy/physics/continuum_mechanics/__init__.py__all__ = ['Beam',
'Truss', 'Cable']
from .beam import Beam
from .truss import Truss
from .cable import Cable
PK ]ZZZ!٘�Q �Q ) sympy/physics/continuum_mechanics/beam.py"""
This module can be used to solve 2D beam bending problems with
singularity functions in mechanics.
"""
from sympy.core import S, Symbol, diff, symbols
from sympy.core.add import Add
from sympy.core.expr import Expr
from sympy.core.function import (Derivative, Function)
from sympy.core.mul import Mul
from sympy.core.relational import Eq
from sympy.core.sympify import sympify
from sympy.solvers import linsolve
from sympy.solvers.ode.ode import dsolve
from sympy.solvers.solvers import solve
from sympy.printing import sstr
from sympy.functions import SingularityFunction, Piecewise, factorial
from sympy.integrals import integrate
from sympy.series import limit
from sympy.plotting import plot, PlotGrid
from sympy.geometry.entity import GeometryEntity
from sympy.external import import_module
from sympy.sets.sets import Interval
from sympy.utilities.lambdify import lambdify
from sympy.utilities.decorator import doctest_depends_on
from sympy.utilities.iterables import iterable
import warnings
__doctest_requires__ = {
('Beam.draw',
'Beam.plot_bending_moment',
'Beam.plot_deflection',
'Beam.plot_ild_moment',
'Beam.plot_ild_shear',
'Beam.plot_shear_force',
'Beam.plot_shear_stress',
'Beam.plot_slope'): ['matplotlib'],
}
numpy = import_module('numpy', import_kwargs={'fromlist':['arange']})
class Beam:
"""
A Beam is a structural element that is capable of withstanding load
primarily by resisting against bending. Beams are characterized by
their cross sectional profile(Second moment of area), their length
and their material.
.. note::
A consistent sign convention must be used while solving a beam
bending problem; the results will
automatically follow the chosen sign convention. However, the
chosen sign convention must respect the rule that, on the positive
side of beam's axis (in respect to current section), a loading force
giving positive shear yields a negative moment, as below (the
curved arrow shows the positive moment and rotation):
.. image:: allowed-sign-conventions.png
Examples
========
There is a beam of length 4 meters. A constant distributed load of 6 N/m
is applied from half of the beam till the end. There are two simple supports
below the beam, one at the starting point and another at the ending point
of the beam. The deflection of the beam at the end is restricted.
Using the sign convention of downwards forces being positive.
>>> from sympy.physics.continuum_mechanics.beam import Beam
>>> from sympy import symbols, Piecewise
>>> E, I = symbols('E, I')
>>> R1, R2 = symbols('R1, R2')
>>> b = Beam(4, E, I)
>>> b.apply_load(R1, 0, -1)
>>> b.apply_load(6, 2, 0)
>>> b.apply_load(R2, 4, -1)
>>> b.bc_deflection = [(0, 0), (4, 0)]
>>> b.boundary_conditions
{'deflection': [(0, 0), (4, 0)], 'slope': []}
>>> b.load
R1*SingularityFunction(x, 0, -1) + R2*SingularityFunction(x, 4, -1) + 6*SingularityFunction(x, 2, 0)
>>> b.solve_for_reaction_loads(R1, R2)
>>> b.load
-3*SingularityFunction(x, 0, -1) + 6*SingularityFunction(x, 2, 0) - 9*SingularityFunction(x, 4, -1)
>>> b.shear_force()
3*SingularityFunction(x, 0, 0) - 6*SingularityFunction(x, 2, 1) + 9*SingularityFunction(x, 4, 0)
>>> b.bending_moment()
3*SingularityFunction(x, 0, 1) - 3*SingularityFunction(x, 2, 2) + 9*SingularityFunction(x, 4, 1)
>>> b.slope()
(-3*SingularityFunction(x, 0, 2)/2 + SingularityFunction(x, 2, 3) - 9*SingularityFunction(x, 4, 2)/2 + 7)/(E*I)
>>> b.deflection()
(7*x - SingularityFunction(x, 0, 3)/2 + SingularityFunction(x, 2, 4)/4 - 3*SingularityFunction(x, 4, 3)/2)/(E*I)
>>> b.deflection().rewrite(Piecewise)
(7*x - Piecewise((x**3, x >= 0), (0, True))/2
- 3*Piecewise(((x - 4)**3, x >= 4), (0, True))/2
+ Piecewise(((x - 2)**4, x >= 2), (0, True))/4)/(E*I)
Calculate the support reactions for a fully symbolic beam of length L.
There are two simple supports below the beam, one at the starting point
and another at the ending point of the beam. The deflection of the beam
at the end is restricted. The beam is loaded with:
* a downward point load P1 applied at L/4
* an upward point load P2 applied at L/8
* a counterclockwise moment M1 applied at L/2
* a clockwise moment M2 applied at 3*L/4
* a distributed constant load q1, applied downward, starting from L/2
up to 3*L/4
* a distributed constant load q2, applied upward, starting from 3*L/4
up to L
No assumptions are needed for symbolic loads. However, defining a positive
length will help the algorithm to compute the solution.
>>> E, I = symbols('E, I')
>>> L = symbols("L", positive=True)
>>> P1, P2, M1, M2, q1, q2 = symbols("P1, P2, M1, M2, q1, q2")
>>> R1, R2 = symbols('R1, R2')
>>> b = Beam(L, E, I)
>>> b.apply_load(R1, 0, -1)
>>> b.apply_load(R2, L, -1)
>>> b.apply_load(P1, L/4, -1)
>>> b.apply_load(-P2, L/8, -1)
>>> b.apply_load(M1, L/2, -2)
>>> b.apply_load(-M2, 3*L/4, -2)
>>> b.apply_load(q1, L/2, 0, 3*L/4)
>>> b.apply_load(-q2, 3*L/4, 0, L)
>>> b.bc_deflection = [(0, 0), (L, 0)]
>>> b.solve_for_reaction_loads(R1, R2)
>>> print(b.reaction_loads[R1])
(-3*L**2*q1 + L**2*q2 - 24*L*P1 + 28*L*P2 - 32*M1 + 32*M2)/(32*L)
>>> print(b.reaction_loads[R2])
(-5*L**2*q1 + 7*L**2*q2 - 8*L*P1 + 4*L*P2 + 32*M1 - 32*M2)/(32*L)
"""
def __init__(self, length, elastic_modulus, second_moment, area=Symbol('A'), variable=Symbol('x'), base_char='C'):
"""Initializes the class.
Parameters
==========
length : Sympifyable
A Symbol or value representing the Beam's length.
elastic_modulus : Sympifyable
A SymPy expression representing the Beam's Modulus of Elasticity.
It is a measure of the stiffness of the Beam material. It can
also be a continuous function of position along the beam.
second_moment : Sympifyable or Geometry object
Describes the cross-section of the beam via a SymPy expression
representing the Beam's second moment of area. It is a geometrical
property of an area which reflects how its points are distributed
with respect to its neutral axis. It can also be a continuous
function of position along the beam. Alternatively ``second_moment``
can be a shape object such as a ``Polygon`` from the geometry module
representing the shape of the cross-section of the beam. In such cases,
it is assumed that the x-axis of the shape object is aligned with the
bending axis of the beam. The second moment of area will be computed
from the shape object internally.
area : Symbol/float
Represents the cross-section area of beam
variable : Symbol, optional
A Symbol object that will be used as the variable along the beam
while representing the load, shear, moment, slope and deflection
curve. By default, it is set to ``Symbol('x')``.
base_char : String, optional
A String that will be used as base character to generate sequential
symbols for integration constants in cases where boundary conditions
are not sufficient to solve them.
"""
self.length = length
self.elastic_modulus = elastic_modulus
if isinstance(second_moment, GeometryEntity):
self.cross_section = second_moment
else:
self.cross_section = None
self.second_moment = second_moment
self.variable = variable
self._base_char = base_char
self._boundary_conditions = {'deflection': [], 'slope': []}
self._load = 0
self.area = area
self._applied_supports = []
self._support_as_loads = []
self._applied_loads = []
self._reaction_loads = {}
self._ild_reactions = {}
self._ild_shear = 0
self._ild_moment = 0
# _original_load is a copy of _load equations with unsubstituted reaction
# forces. It is used for calculating reaction forces in case of I.L.D.
self._original_load = 0
self._composite_type = None
self._hinge_position = None
def __str__(self):
shape_description = self._cross_section if self._cross_section else self._second_moment
str_sol = 'Beam({}, {}, {})'.format(sstr(self._length), sstr(self._elastic_modulus), sstr(shape_description))
return str_sol
@property
def reaction_loads(self):
""" Returns the reaction forces in a dictionary."""
return self._reaction_loads
@property
def ild_shear(self):
""" Returns the I.L.D. shear equation."""
return self._ild_shear
@property
def ild_reactions(self):
""" Returns the I.L.D. reaction forces in a dictionary."""
return self._ild_reactions
@property
def ild_moment(self):
""" Returns the I.L.D. moment equation."""
return self._ild_moment
@property
def length(self):
"""Length of the Beam."""
return self._length
@length.setter
def length(self, l):
self._length = sympify(l)
@property
def area(self):
"""Cross-sectional area of the Beam. """
return self._area
@area.setter
def area(self, a):
self._area = sympify(a)
@property
def variable(self):
"""
A symbol that can be used as a variable along the length of the beam
while representing load distribution, shear force curve, bending
moment, slope curve and the deflection curve. By default, it is set
to ``Symbol('x')``, but this property is mutable.
Examples
========
>>> from sympy.physics.continuum_mechanics.beam import Beam
>>> from sympy import symbols
>>> E, I, A = symbols('E, I, A')
>>> x, y, z = symbols('x, y, z')
>>> b = Beam(4, E, I)
>>> b.variable
x
>>> b.variable = y
>>> b.variable
y
>>> b = Beam(4, E, I, A, z)
>>> b.variable
z
"""
return self._variable
@variable.setter
def variable(self, v):
if isinstance(v, Symbol):
self._variable = v
else:
raise TypeError("""The variable should be a Symbol object.""")
@property
def elastic_modulus(self):
"""Young's Modulus of the Beam. """
return self._elastic_modulus
@elastic_modulus.setter
def elastic_modulus(self, e):
self._elastic_modulus = sympify(e)
@property
def second_moment(self):
"""Second moment of area of the Beam. """
return self._second_moment
@second_moment.setter
def second_moment(self, i):
self._cross_section = None
if isinstance(i, GeometryEntity):
raise ValueError("To update cross-section geometry use `cross_section` attribute")
else:
self._second_moment = sympify(i)
@property
def cross_section(self):
"""Cross-section of the beam"""
return self._cross_section
@cross_section.setter
def cross_section(self, s):
if s:
self._second_moment = s.second_moment_of_area()[0]
self._cross_section = s
@property
def boundary_conditions(self):
"""
Returns a dictionary of boundary conditions applied on the beam.
The dictionary has three keywords namely moment, slope and deflection.
The value of each keyword is a list of tuple, where each tuple
contains location and value of a boundary condition in the format
(location, value).
Examples
========
There is a beam of length 4 meters. The bending moment at 0 should be 4
and at 4 it should be 0. The slope of the beam should be 1 at 0. The
deflection should be 2 at 0.
>>> from sympy.physics.continuum_mechanics.beam import Beam
>>> from sympy import symbols
>>> E, I = symbols('E, I')
>>> b = Beam(4, E, I)
>>> b.bc_deflection = [(0, 2)]
>>> b.bc_slope = [(0, 1)]
>>> b.boundary_conditions
{'deflection': [(0, 2)], 'slope': [(0, 1)]}
Here the deflection of the beam should be ``2`` at ``0``.
Similarly, the slope of the beam should be ``1`` at ``0``.
"""
return self._boundary_conditions
@property
def bc_slope(self):
return self._boundary_conditions['slope']
@bc_slope.setter
def bc_slope(self, s_bcs):
self._boundary_conditions['slope'] = s_bcs
@property
def bc_deflection(self):
return self._boundary_conditions['deflection']
@bc_deflection.setter
def bc_deflection(self, d_bcs):
self._boundary_conditions['deflection'] = d_bcs
def join(self, beam, via="fixed"):
"""
This method joins two beams to make a new composite beam system.
Passed Beam class instance is attached to the right end of calling
object. This method can be used to form beams having Discontinuous
values of Elastic modulus or Second moment.
Parameters
==========
beam : Beam class object
The Beam object which would be connected to the right of calling
object.
via : String
States the way two Beam object would get connected
- For axially fixed Beams, via="fixed"
- For Beams connected via hinge, via="hinge"
Examples
========
There is a cantilever beam of length 4 meters. For first 2 meters
its moment of inertia is `1.5*I` and `I` for the other end.
A pointload of magnitude 4 N is applied from the top at its free end.
>>> from sympy.physics.continuum_mechanics.beam import Beam
>>> from sympy import symbols
>>> E, I = symbols('E, I')
>>> R1, R2 = symbols('R1, R2')
>>> b1 = Beam(2, E, 1.5*I)
>>> b2 = Beam(2, E, I)
>>> b = b1.join(b2, "fixed")
>>> b.apply_load(20, 4, -1)
>>> b.apply_load(R1, 0, -1)
>>> b.apply_load(R2, 0, -2)
>>> b.bc_slope = [(0, 0)]
>>> b.bc_deflection = [(0, 0)]
>>> b.solve_for_reaction_loads(R1, R2)
>>> b.load
80*SingularityFunction(x, 0, -2) - 20*SingularityFunction(x, 0, -1) + 20*SingularityFunction(x, 4, -1)
>>> b.slope()
(-((-80*SingularityFunction(x, 0, 1) + 10*SingularityFunction(x, 0, 2) - 10*SingularityFunction(x, 4, 2))/I + 120/I)/E + 80.0/(E*I))*SingularityFunction(x, 2, 0)
- 0.666666666666667*(-80*SingularityFunction(x, 0, 1) + 10*SingularityFunction(x, 0, 2) - 10*SingularityFunction(x, 4, 2))*SingularityFunction(x, 0, 0)/(E*I)
+ 0.666666666666667*(-80*SingularityFunction(x, 0, 1) + 10*SingularityFunction(x, 0, 2) - 10*SingularityFunction(x, 4, 2))*SingularityFunction(x, 2, 0)/(E*I)
"""
x = self.variable
E = self.elastic_modulus
new_length = self.length + beam.length
if self.second_moment != beam.second_moment:
new_second_moment = Piecewise((self.second_moment, x<=self.length),
(beam.second_moment, x<=new_length))
else:
new_second_moment = self.second_moment
if via == "fixed":
new_beam = Beam(new_length, E, new_second_moment, x)
new_beam._composite_type = "fixed"
return new_beam
if via == "hinge":
new_beam = Beam(new_length, E, new_second_moment, x)
new_beam._composite_type = "hinge"
new_beam._hinge_position = self.length
return new_beam
def apply_support(self, loc, type="fixed"):
"""
This method applies support to a particular beam object and returns
the symbol of the unknown reaction load(s).
Parameters
==========
loc : Sympifyable
Location of point at which support is applied.
type : String
Determines type of Beam support applied. To apply support structure
with
- zero degree of freedom, type = "fixed"
- one degree of freedom, type = "pin"
- two degrees of freedom, type = "roller"
Returns
=======
Symbol or tuple of Symbol
The unknown reaction load as a symbol.
- Symbol(reaction_force) if type = "pin" or "roller"
- Symbol(reaction_force), Symbol(reaction_moment) if type = "fixed"
Examples
========
There is a beam of length 20 meters. A moment of magnitude 100 Nm is
applied in the clockwise direction at the end of the beam. A pointload
of magnitude 8 N is applied from the top of the beam at a distance of 10 meters.
There is one fixed support at the start of the beam and a roller at the end.
Using the sign convention of upward forces and clockwise moment
being positive.
>>> from sympy.physics.continuum_mechanics.beam import Beam
>>> from sympy import symbols
>>> E, I = symbols('E, I')
>>> b = Beam(20, E, I)
>>> p0, m0 = b.apply_support(0, 'fixed')
>>> p1 = b.apply_support(20, 'roller')
>>> b.apply_load(-8, 10, -1)
>>> b.apply_load(100, 20, -2)
>>> b.solve_for_reaction_loads(p0, m0, p1)
>>> b.reaction_loads
{M_0: 20, R_0: -2, R_20: 10}
>>> b.reaction_loads[p0]
-2
>>> b.load
20*SingularityFunction(x, 0, -2) - 2*SingularityFunction(x, 0, -1)
- 8*SingularityFunction(x, 10, -1) + 100*SingularityFunction(x, 20, -2)
+ 10*SingularityFunction(x, 20, -1)
"""
loc = sympify(loc)
self._applied_supports.append((loc, type))
if type in ("pin", "roller"):
reaction_load = Symbol('R_'+str(loc))
self.apply_load(reaction_load, loc, -1)
self.bc_deflection.append((loc, 0))
else:
reaction_load = Symbol('R_'+str(loc))
reaction_moment = Symbol('M_'+str(loc))
self.apply_load(reaction_load, loc, -1)
self.apply_load(reaction_moment, loc, -2)
self.bc_deflection.append((loc, 0))
self.bc_slope.append((loc, 0))
self._support_as_loads.append((reaction_moment, loc, -2, None))
self._support_as_loads.append((reaction_load, loc, -1, None))
if type in ("pin", "roller"):
return reaction_load
else:
return reaction_load, reaction_moment
def apply_load(self, value, start, order, end=None):
"""
This method adds up the loads given to a particular beam object.
Parameters
==========
value : Sympifyable
The value inserted should have the units [Force/(Distance**(n+1)]
where n is the order of applied load.
Units for applied loads:
- For moments, unit = kN*m
- For point loads, unit = kN
- For constant distributed load, unit = kN/m
- For ramp loads, unit = kN/m/m
- For parabolic ramp loads, unit = kN/m/m/m
- ... so on.
start : Sympifyable
The starting point of the applied load. For point moments and
point forces this is the location of application.
order : Integer
The order of the applied load.
- For moments, order = -2
- For point loads, order =-1
- For constant distributed load, order = 0
- For ramp loads, order = 1
- For parabolic ramp loads, order = 2
- ... so on.
end : Sympifyable, optional
An optional argument that can be used if the load has an end point
within the length of the beam.
Examples
========
There is a beam of length 4 meters. A moment of magnitude 3 Nm is
applied in the clockwise direction at the starting point of the beam.
A point load of magnitude 4 N is applied from the top of the beam at
2 meters from the starting point and a parabolic ramp load of magnitude
2 N/m is applied below the beam starting from 2 meters to 3 meters
away from the starting point of the beam.
>>> from sympy.physics.continuum_mechanics.beam import Beam
>>> from sympy import symbols
>>> E, I = symbols('E, I')
>>> b = Beam(4, E, I)
>>> b.apply_load(-3, 0, -2)
>>> b.apply_load(4, 2, -1)
>>> b.apply_load(-2, 2, 2, end=3)
>>> b.load
-3*SingularityFunction(x, 0, -2) + 4*SingularityFunction(x, 2, -1) - 2*SingularityFunction(x, 2, 2) + 2*SingularityFunction(x, 3, 0) + 4*SingularityFunction(x, 3, 1) + 2*SingularityFunction(x, 3, 2)
"""
x = self.variable
value = sympify(value)
start = sympify(start)
order = sympify(order)
self._applied_loads.append((value, start, order, end))
self._load += value*SingularityFunction(x, start, order)
self._original_load += value*SingularityFunction(x, start, order)
if end:
# load has an end point within the length of the beam.
self._handle_end(x, value, start, order, end, type="apply")
def remove_load(self, value, start, order, end=None):
"""
This method removes a particular load present on the beam object.
Returns a ValueError if the load passed as an argument is not
present on the beam.
Parameters
==========
value : Sympifyable
The magnitude of an applied load.
start : Sympifyable
The starting point of the applied load. For point moments and
point forces this is the location of application.
order : Integer
The order of the applied load.
- For moments, order= -2
- For point loads, order=-1
- For constant distributed load, order=0
- For ramp loads, order=1
- For parabolic ramp loads, order=2
- ... so on.
end : Sympifyable, optional
An optional argument that can be used if the load has an end point
within the length of the beam.
Examples
========
There is a beam of length 4 meters. A moment of magnitude 3 Nm is
applied in the clockwise direction at the starting point of the beam.
A pointload of magnitude 4 N is applied from the top of the beam at
2 meters from the starting point and a parabolic ramp load of magnitude
2 N/m is applied below the beam starting from 2 meters to 3 meters
away from the starting point of the beam.
>>> from sympy.physics.continuum_mechanics.beam import Beam
>>> from sympy import symbols
>>> E, I = symbols('E, I')
>>> b = Beam(4, E, I)
>>> b.apply_load(-3, 0, -2)
>>> b.apply_load(4, 2, -1)
>>> b.apply_load(-2, 2, 2, end=3)
>>> b.load
-3*SingularityFunction(x, 0, -2) + 4*SingularityFunction(x, 2, -1) - 2*SingularityFunction(x, 2, 2) + 2*SingularityFunction(x, 3, 0) + 4*SingularityFunction(x, 3, 1) + 2*SingularityFunction(x, 3, 2)
>>> b.remove_load(-2, 2, 2, end = 3)
>>> b.load
-3*SingularityFunction(x, 0, -2) + 4*SingularityFunction(x, 2, -1)
"""
x = self.variable
value = sympify(value)
start = sympify(start)
order = sympify(order)
if (value, start, order, end) in self._applied_loads:
self._load -= value*SingularityFunction(x, start, order)
self._original_load -= value*SingularityFunction(x, start, order)
self._applied_loads.remove((value, start, order, end))
else:
msg = "No such load distribution exists on the beam object."
raise ValueError(msg)
if end:
# load has an end point within the length of the beam.
self._handle_end(x, value, start, order, end, type="remove")
def _handle_end(self, x, value, start, order, end, type):
"""
This functions handles the optional `end` value in the
`apply_load` and `remove_load` functions. When the value
of end is not NULL, this function will be executed.
"""
if order.is_negative:
msg = ("If 'end' is provided the 'order' of the load cannot "
"be negative, i.e. 'end' is only valid for distributed "
"loads.")
raise ValueError(msg)
# NOTE : A Taylor series can be used to define the summation of
# singularity functions that subtract from the load past the end
# point such that it evaluates to zero past 'end'.
f = value*x**order
if type == "apply":
# iterating for "apply_load" method
for i in range(0, order + 1):
self._load -= (f.diff(x, i).subs(x, end - start) *
SingularityFunction(x, end, i)/factorial(i))
self._original_load -= (f.diff(x, i).subs(x, end - start) *
SingularityFunction(x, end, i)/factorial(i))
elif type == "remove":
# iterating for "remove_load" method
for i in range(0, order + 1):
self._load += (f.diff(x, i).subs(x, end - start) *
SingularityFunction(x, end, i)/factorial(i))
self._original_load += (f.diff(x, i).subs(x, end - start) *
SingularityFunction(x, end, i)/factorial(i))
@property
def load(self):
"""
Returns a Singularity Function expression which represents
the load distribution curve of the Beam object.
Examples
========
There is a beam of length 4 meters. A moment of magnitude 3 Nm is
applied in the clockwise direction at the starting point of the beam.
A point load of magnitude 4 N is applied from the top of the beam at
2 meters from the starting point and a parabolic ramp load of magnitude
2 N/m is applied below the beam starting from 3 meters away from the
starting point of the beam.
>>> from sympy.physics.continuum_mechanics.beam import Beam
>>> from sympy import symbols
>>> E, I = symbols('E, I')
>>> b = Beam(4, E, I)
>>> b.apply_load(-3, 0, -2)
>>> b.apply_load(4, 2, -1)
>>> b.apply_load(-2, 3, 2)
>>> b.load
-3*SingularityFunction(x, 0, -2) + 4*SingularityFunction(x, 2, -1) - 2*SingularityFunction(x, 3, 2)
"""
return self._load
@property
def applied_loads(self):
"""
Returns a list of all loads applied on the beam object.
Each load in the list is a tuple of form (value, start, order, end).
Examples
========
There is a beam of length 4 meters. A moment of magnitude 3 Nm is
applied in the clockwise direction at the starting point of the beam.
A pointload of magnitude 4 N is applied from the top of the beam at
2 meters from the starting point. Another pointload of magnitude 5 N
is applied at same position.
>>> from sympy.physics.continuum_mechanics.beam import Beam
>>> from sympy import symbols
>>> E, I = symbols('E, I')
>>> b = Beam(4, E, I)
>>> b.apply_load(-3, 0, -2)
>>> b.apply_load(4, 2, -1)
>>> b.apply_load(5, 2, -1)
>>> b.load
-3*SingularityFunction(x, 0, -2) + 9*SingularityFunction(x, 2, -1)
>>> b.applied_loads
[(-3, 0, -2, None), (4, 2, -1, None), (5, 2, -1, None)]
"""
return self._applied_loads
def _solve_hinge_beams(self, *reactions):
"""Method to find integration constants and reactional variables in a
composite beam connected via hinge.
This method resolves the composite Beam into its sub-beams and then
equations of shear force, bending moment, slope and deflection are
evaluated for both of them separately. These equations are then solved
for unknown reactions and integration constants using the boundary
conditions applied on the Beam. Equal deflection of both sub-beams
at the hinge joint gives us another equation to solve the system.
Examples
========
A combined beam, with constant fkexural rigidity E*I, is formed by joining
a Beam of length 2*l to the right of another Beam of length l. The whole beam
is fixed at both of its both end. A point load of magnitude P is also applied
from the top at a distance of 2*l from starting point.
>>> from sympy.physics.continuum_mechanics.beam import Beam
>>> from sympy import symbols
>>> E, I = symbols('E, I')
>>> l=symbols('l', positive=True)
>>> b1=Beam(l, E, I)
>>> b2=Beam(2*l, E, I)
>>> b=b1.join(b2,"hinge")
>>> M1, A1, M2, A2, P = symbols('M1 A1 M2 A2 P')
>>> b.apply_load(A1,0,-1)
>>> b.apply_load(M1,0,-2)
>>> b.apply_load(P,2*l,-1)
>>> b.apply_load(A2,3*l,-1)
>>> b.apply_load(M2,3*l,-2)
>>> b.bc_slope=[(0,0), (3*l, 0)]
>>> b.bc_deflection=[(0,0), (3*l, 0)]
>>> b.solve_for_reaction_loads(M1, A1, M2, A2)
>>> b.reaction_loads
{A1: -5*P/18, A2: -13*P/18, M1: 5*P*l/18, M2: -4*P*l/9}
>>> b.slope()
(5*P*l*SingularityFunction(x, 0, 1)/18 - 5*P*SingularityFunction(x, 0, 2)/36 + 5*P*SingularityFunction(x, l, 2)/36)*SingularityFunction(x, 0, 0)/(E*I)
- (5*P*l*SingularityFunction(x, 0, 1)/18 - 5*P*SingularityFunction(x, 0, 2)/36 + 5*P*SingularityFunction(x, l, 2)/36)*SingularityFunction(x, l, 0)/(E*I)
+ (P*l**2/18 - 4*P*l*SingularityFunction(-l + x, 2*l, 1)/9 - 5*P*SingularityFunction(-l + x, 0, 2)/36 + P*SingularityFunction(-l + x, l, 2)/2
- 13*P*SingularityFunction(-l + x, 2*l, 2)/36)*SingularityFunction(x, l, 0)/(E*I)
>>> b.deflection()
(5*P*l*SingularityFunction(x, 0, 2)/36 - 5*P*SingularityFunction(x, 0, 3)/108 + 5*P*SingularityFunction(x, l, 3)/108)*SingularityFunction(x, 0, 0)/(E*I)
- (5*P*l*SingularityFunction(x, 0, 2)/36 - 5*P*SingularityFunction(x, 0, 3)/108 + 5*P*SingularityFunction(x, l, 3)/108)*SingularityFunction(x, l, 0)/(E*I)
+ (5*P*l**3/54 + P*l**2*(-l + x)/18 - 2*P*l*SingularityFunction(-l + x, 2*l, 2)/9 - 5*P*SingularityFunction(-l + x, 0, 3)/108 + P*SingularityFunction(-l + x, l, 3)/6
- 13*P*SingularityFunction(-l + x, 2*l, 3)/108)*SingularityFunction(x, l, 0)/(E*I)
"""
x = self.variable
l = self._hinge_position
E = self._elastic_modulus
I = self._second_moment
if isinstance(I, Piecewise):
I1 = I.args[0][0]
I2 = I.args[1][0]
else:
I1 = I2 = I
load_1 = 0 # Load equation on first segment of composite beam
load_2 = 0 # Load equation on second segment of composite beam
# Distributing load on both segments
for load in self.applied_loads:
if load[1] < l:
load_1 += load[0]*SingularityFunction(x, load[1], load[2])
if load[2] == 0:
load_1 -= load[0]*SingularityFunction(x, load[3], load[2])
elif load[2] > 0:
load_1 -= load[0]*SingularityFunction(x, load[3], load[2]) + load[0]*SingularityFunction(x, load[3], 0)
elif load[1] == l:
load_1 += load[0]*SingularityFunction(x, load[1], load[2])
load_2 += load[0]*SingularityFunction(x, load[1] - l, load[2])
elif load[1] > l:
load_2 += load[0]*SingularityFunction(x, load[1] - l, load[2])
if load[2] == 0:
load_2 -= load[0]*SingularityFunction(x, load[3] - l, load[2])
elif load[2] > 0:
load_2 -= load[0]*SingularityFunction(x, load[3] - l, load[2]) + load[0]*SingularityFunction(x, load[3] - l, 0)
h = Symbol('h') # Force due to hinge
load_1 += h*SingularityFunction(x, l, -1)
load_2 -= h*SingularityFunction(x, 0, -1)
eq = []
shear_1 = integrate(load_1, x)
shear_curve_1 = limit(shear_1, x, l)
eq.append(shear_curve_1)
bending_1 = integrate(shear_1, x)
moment_curve_1 = limit(bending_1, x, l)
eq.append(moment_curve_1)
shear_2 = integrate(load_2, x)
shear_curve_2 = limit(shear_2, x, self.length - l)
eq.append(shear_curve_2)
bending_2 = integrate(shear_2, x)
moment_curve_2 = limit(bending_2, x, self.length - l)
eq.append(moment_curve_2)
C1 = Symbol('C1')
C2 = Symbol('C2')
C3 = Symbol('C3')
C4 = Symbol('C4')
slope_1 = S.One/(E*I1)*(integrate(bending_1, x) + C1)
def_1 = S.One/(E*I1)*(integrate((E*I)*slope_1, x) + C1*x + C2)
slope_2 = S.One/(E*I2)*(integrate(integrate(integrate(load_2, x), x), x) + C3)
def_2 = S.One/(E*I2)*(integrate((E*I)*slope_2, x) + C4)
for position, value in self.bc_slope:
if position<l:
eq.append(slope_1.subs(x, position) - value)
else:
eq.append(slope_2.subs(x, position - l) - value)
for position, value in self.bc_deflection:
if position<l:
eq.append(def_1.subs(x, position) - value)
else:
eq.append(def_2.subs(x, position - l) - value)
eq.append(def_1.subs(x, l) - def_2.subs(x, 0)) # Deflection of both the segments at hinge would be equal
constants = list(linsolve(eq, C1, C2, C3, C4, h, *reactions))
reaction_values = list(constants[0])[5:]
self._reaction_loads = dict(zip(reactions, reaction_values))
self._load = self._load.subs(self._reaction_loads)
# Substituting constants and reactional load and moments with their corresponding values
slope_1 = slope_1.subs({C1: constants[0][0], h:constants[0][4]}).subs(self._reaction_loads)
def_1 = def_1.subs({C1: constants[0][0], C2: constants[0][1], h:constants[0][4]}).subs(self._reaction_loads)
slope_2 = slope_2.subs({x: x-l, C3: constants[0][2], h:constants[0][4]}).subs(self._reaction_loads)
def_2 = def_2.subs({x: x-l,C3: constants[0][2], C4: constants[0][3], h:constants[0][4]}).subs(self._reaction_loads)
self._hinge_beam_slope = slope_1*SingularityFunction(x, 0, 0) - slope_1*SingularityFunction(x, l, 0) + slope_2*SingularityFunction(x, l, 0)
self._hinge_beam_deflection = def_1*SingularityFunction(x, 0, 0) - def_1*SingularityFunction(x, l, 0) + def_2*SingularityFunction(x, l, 0)
def solve_for_reaction_loads(self, *reactions):
"""
Solves for the reaction forces.
Examples
========
There is a beam of length 30 meters. A moment of magnitude 120 Nm is
applied in the clockwise direction at the end of the beam. A pointload
of magnitude 8 N is applied from the top of the beam at the starting
point. There are two simple supports below the beam. One at the end
and another one at a distance of 10 meters from the start. The
deflection is restricted at both the supports.
Using the sign convention of upward forces and clockwise moment
being positive.
>>> from sympy.physics.continuum_mechanics.beam import Beam
>>> from sympy import symbols
>>> E, I = symbols('E, I')
>>> R1, R2 = symbols('R1, R2')
>>> b = Beam(30, E, I)
>>> b.apply_load(-8, 0, -1)
>>> b.apply_load(R1, 10, -1) # Reaction force at x = 10
>>> b.apply_load(R2, 30, -1) # Reaction force at x = 30
>>> b.apply_load(120, 30, -2)
>>> b.bc_deflection = [(10, 0), (30, 0)]
>>> b.load
R1*SingularityFunction(x, 10, -1) + R2*SingularityFunction(x, 30, -1)
- 8*SingularityFunction(x, 0, -1) + 120*SingularityFunction(x, 30, -2)
>>> b.solve_for_reaction_loads(R1, R2)
>>> b.reaction_loads
{R1: 6, R2: 2}
>>> b.load
-8*SingularityFunction(x, 0, -1) + 6*SingularityFunction(x, 10, -1)
+ 120*SingularityFunction(x, 30, -2) + 2*SingularityFunction(x, 30, -1)
"""
if self._composite_type == "hinge":
return self._solve_hinge_beams(*reactions)
x = self.variable
l = self.length
C3 = Symbol('C3')
C4 = Symbol('C4')
shear_curve = limit(self.shear_force(), x, l)
moment_curve = limit(self.bending_moment(), x, l)
slope_eqs = []
deflection_eqs = []
slope_curve = integrate(self.bending_moment(), x) + C3
for position, value in self._boundary_conditions['slope']:
eqs = slope_curve.subs(x, position) - value
slope_eqs.append(eqs)
deflection_curve = integrate(slope_curve, x) + C4
for position, value in self._boundary_conditions['deflection']:
eqs = deflection_curve.subs(x, position) - value
deflection_eqs.append(eqs)
solution = list((linsolve([shear_curve, moment_curve] + slope_eqs
+ deflection_eqs, (C3, C4) + reactions).args)[0])
solution = solution[2:]
self._reaction_loads = dict(zip(reactions, solution))
self._load = self._load.subs(self._reaction_loads)
def shear_force(self):
"""
Returns a Singularity Function expression which represents
the shear force curve of the Beam object.
Examples
========
There is a beam of length 30 meters. A moment of magnitude 120 Nm is
applied in the clockwise direction at the end of the beam. A pointload
of magnitude 8 N is applied from the top of the beam at the starting
point. There are two simple supports below the beam. One at the end
and another one at a distance of 10 meters from the start. The
deflection is restricted at both the supports.
Using the sign convention of upward forces and clockwise moment
being positive.
>>> from sympy.physics.continuum_mechanics.beam import Beam
>>> from sympy import symbols
>>> E, I = symbols('E, I')
>>> R1, R2 = symbols('R1, R2')
>>> b = Beam(30, E, I)
>>> b.apply_load(-8, 0, -1)
>>> b.apply_load(R1, 10, -1)
>>> b.apply_load(R2, 30, -1)
>>> b.apply_load(120, 30, -2)
>>> b.bc_deflection = [(10, 0), (30, 0)]
>>> b.solve_for_reaction_loads(R1, R2)
>>> b.shear_force()
8*SingularityFunction(x, 0, 0) - 6*SingularityFunction(x, 10, 0) - 120*SingularityFunction(x, 30, -1) - 2*SingularityFunction(x, 30, 0)
"""
x = self.variable
return -integrate(self.load, x)
def max_shear_force(self):
"""Returns maximum Shear force and its coordinate
in the Beam object."""
shear_curve = self.shear_force()
x = self.variable
terms = shear_curve.args
singularity = [] # Points at which shear function changes
for term in terms:
if isinstance(term, Mul):
term = term.args[-1] # SingularityFunction in the term
singularity.append(term.args[1])
singularity = list(set(singularity))
singularity.sort()
intervals = [] # List of Intervals with discrete value of shear force
shear_values = [] # List of values of shear force in each interval
for i, s in enumerate(singularity):
if s == 0:
continue
try:
shear_slope = Piecewise((float("nan"), x<=singularity[i-1]),(self._load.rewrite(Piecewise), x<s), (float("nan"), True))
points = solve(shear_slope, x)
val = []
for point in points:
val.append(abs(shear_curve.subs(x, point)))
points.extend([singularity[i-1], s])
val += [abs(limit(shear_curve, x, singularity[i-1], '+')), abs(limit(shear_curve, x, s, '-'))]
max_shear = max(val)
shear_values.append(max_shear)
intervals.append(points[val.index(max_shear)])
# If shear force in a particular Interval has zero or constant
# slope, then above block gives NotImplementedError as
# solve can't represent Interval solutions.
except NotImplementedError:
initial_shear = limit(shear_curve, x, singularity[i-1], '+')
final_shear = limit(shear_curve, x, s, '-')
# If shear_curve has a constant slope(it is a line).
if shear_curve.subs(x, (singularity[i-1] + s)/2) == (initial_shear + final_shear)/2 and initial_shear != final_shear:
shear_values.extend([initial_shear, final_shear])
intervals.extend([singularity[i-1], s])
else: # shear_curve has same value in whole Interval
shear_values.append(final_shear)
intervals.append(Interval(singularity[i-1], s))
shear_values = list(map(abs, shear_values))
maximum_shear = max(shear_values)
point = intervals[shear_values.index(maximum_shear)]
return (point, maximum_shear)
def bending_moment(self):
"""
Returns a Singularity Function expression which represents
the bending moment curve of the Beam object.
Examples
========
There is a beam of length 30 meters. A moment of magnitude 120 Nm is
applied in the clockwise direction at the end of the beam. A pointload
of magnitude 8 N is applied from the top of the beam at the starting
point. There are two simple supports below the beam. One at the end
and another one at a distance of 10 meters from the start. The
deflection is restricted at both the supports.
Using the sign convention of upward forces and clockwise moment
being positive.
>>> from sympy.physics.continuum_mechanics.beam import Beam
>>> from sympy import symbols
>>> E, I = symbols('E, I')
>>> R1, R2 = symbols('R1, R2')
>>> b = Beam(30, E, I)
>>> b.apply_load(-8, 0, -1)
>>> b.apply_load(R1, 10, -1)
>>> b.apply_load(R2, 30, -1)
>>> b.apply_load(120, 30, -2)
>>> b.bc_deflection = [(10, 0), (30, 0)]
>>> b.solve_for_reaction_loads(R1, R2)
>>> b.bending_moment()
8*SingularityFunction(x, 0, 1) - 6*SingularityFunction(x, 10, 1) - 120*SingularityFunction(x, 30, 0) - 2*SingularityFunction(x, 30, 1)
"""
x = self.variable
return integrate(self.shear_force(), x)
def max_bmoment(self):
"""Returns maximum Shear force and its coordinate
in the Beam object."""
bending_curve = self.bending_moment()
x = self.variable
terms = bending_curve.args
singularity = [] # Points at which bending moment changes
for term in terms:
if isinstance(term, Mul):
term = term.args[-1] # SingularityFunction in the term
singularity.append(term.args[1])
singularity = list(set(singularity))
singularity.sort()
intervals = [] # List of Intervals with discrete value of bending moment
moment_values = [] # List of values of bending moment in each interval
for i, s in enumerate(singularity):
if s == 0:
continue
try:
moment_slope = Piecewise(
(float("nan"), x <= singularity[i - 1]),
(self.shear_force().rewrite(Piecewise), x < s),
(float("nan"), True))
points = solve(moment_slope, x)
val = []
for point in points:
val.append(abs(bending_curve.subs(x, point)))
points.extend([singularity[i-1], s])
val += [abs(limit(bending_curve, x, singularity[i-1], '+')), abs(limit(bending_curve, x, s, '-'))]
max_moment = max(val)
moment_values.append(max_moment)
intervals.append(points[val.index(max_moment)])
# If bending moment in a particular Interval has zero or constant
# slope, then above block gives NotImplementedError as solve
# can't represent Interval solutions.
except NotImplementedError:
initial_moment = limit(bending_curve, x, singularity[i-1], '+')
final_moment = limit(bending_curve, x, s, '-')
# If bending_curve has a constant slope(it is a line).
if bending_curve.subs(x, (singularity[i-1] + s)/2) == (initial_moment + final_moment)/2 and initial_moment != final_moment:
moment_values.extend([initial_moment, final_moment])
intervals.extend([singularity[i-1], s])
else: # bending_curve has same value in whole Interval
moment_values.append(final_moment)
intervals.append(Interval(singularity[i-1], s))
moment_values = list(map(abs, moment_values))
maximum_moment = max(moment_values)
point = intervals[moment_values.index(maximum_moment)]
return (point, maximum_moment)
def point_cflexure(self):
"""
Returns a Set of point(s) with zero bending moment and
where bending moment curve of the beam object changes
its sign from negative to positive or vice versa.
Examples
========
There is is 10 meter long overhanging beam. There are
two simple supports below the beam. One at the start
and another one at a distance of 6 meters from the start.
Point loads of magnitude 10KN and 20KN are applied at
2 meters and 4 meters from start respectively. A Uniformly
distribute load of magnitude of magnitude 3KN/m is also
applied on top starting from 6 meters away from starting
point till end.
Using the sign convention of upward forces and clockwise moment
being positive.
>>> from sympy.physics.continuum_mechanics.beam import Beam
>>> from sympy import symbols
>>> E, I = symbols('E, I')
>>> b = Beam(10, E, I)
>>> b.apply_load(-4, 0, -1)
>>> b.apply_load(-46, 6, -1)
>>> b.apply_load(10, 2, -1)
>>> b.apply_load(20, 4, -1)
>>> b.apply_load(3, 6, 0)
>>> b.point_cflexure()
[10/3]
"""
# To restrict the range within length of the Beam
moment_curve = Piecewise((float("nan"), self.variable<=0),
(self.bending_moment(), self.variable<self.length),
(float("nan"), True))
points = solve(moment_curve.rewrite(Piecewise), self.variable,
domain=S.Reals)
return points
def slope(self):
"""
Returns a Singularity Function expression which represents
the slope the elastic curve of the Beam object.
Examples
========
There is a beam of length 30 meters. A moment of magnitude 120 Nm is
applied in the clockwise direction at the end of the beam. A pointload
of magnitude 8 N is applied from the top of the beam at the starting
point. There are two simple supports below the beam. One at the end
and another one at a distance of 10 meters from the start. The
deflection is restricted at both the supports.
Using the sign convention of upward forces and clockwise moment
being positive.
>>> from sympy.physics.continuum_mechanics.beam import Beam
>>> from sympy import symbols
>>> E, I = symbols('E, I')
>>> R1, R2 = symbols('R1, R2')
>>> b = Beam(30, E, I)
>>> b.apply_load(-8, 0, -1)
>>> b.apply_load(R1, 10, -1)
>>> b.apply_load(R2, 30, -1)
>>> b.apply_load(120, 30, -2)
>>> b.bc_deflection = [(10, 0), (30, 0)]
>>> b.solve_for_reaction_loads(R1, R2)
>>> b.slope()
(-4*SingularityFunction(x, 0, 2) + 3*SingularityFunction(x, 10, 2)
+ 120*SingularityFunction(x, 30, 1) + SingularityFunction(x, 30, 2) + 4000/3)/(E*I)
"""
x = self.variable
E = self.elastic_modulus
I = self.second_moment
if self._composite_type == "hinge":
return self._hinge_beam_slope
if not self._boundary_conditions['slope']:
return diff(self.deflection(), x)
if isinstance(I, Piecewise) and self._composite_type == "fixed":
args = I.args
slope = 0
prev_slope = 0
prev_end = 0
for i in range(len(args)):
if i != 0:
prev_end = args[i-1][1].args[1]
slope_value = -S.One/E*integrate(self.bending_moment()/args[i][0], (x, prev_end, x))
if i != len(args) - 1:
slope += (prev_slope + slope_value)*SingularityFunction(x, prev_end, 0) - \
(prev_slope + slope_value)*SingularityFunction(x, args[i][1].args[1], 0)
else:
slope += (prev_slope + slope_value)*SingularityFunction(x, prev_end, 0)
prev_slope = slope_value.subs(x, args[i][1].args[1])
return slope
C3 = Symbol('C3')
slope_curve = -integrate(S.One/(E*I)*self.bending_moment(), x) + C3
bc_eqs = []
for position, value in self._boundary_conditions['slope']:
eqs = slope_curve.subs(x, position) - value
bc_eqs.append(eqs)
constants = list(linsolve(bc_eqs, C3))
slope_curve = slope_curve.subs({C3: constants[0][0]})
return slope_curve
def deflection(self):
"""
Returns a Singularity Function expression which represents
the elastic curve or deflection of the Beam object.
Examples
========
There is a beam of length 30 meters. A moment of magnitude 120 Nm is
applied in the clockwise direction at the end of the beam. A pointload
of magnitude 8 N is applied from the top of the beam at the starting
point. There are two simple supports below the beam. One at the end
and another one at a distance of 10 meters from the start. The
deflection is restricted at both the supports.
Using the sign convention of upward forces and clockwise moment
being positive.
>>> from sympy.physics.continuum_mechanics.beam import Beam
>>> from sympy import symbols
>>> E, I = symbols('E, I')
>>> R1, R2 = symbols('R1, R2')
>>> b = Beam(30, E, I)
>>> b.apply_load(-8, 0, -1)
>>> b.apply_load(R1, 10, -1)
>>> b.apply_load(R2, 30, -1)
>>> b.apply_load(120, 30, -2)
>>> b.bc_deflection = [(10, 0), (30, 0)]
>>> b.solve_for_reaction_loads(R1, R2)
>>> b.deflection()
(4000*x/3 - 4*SingularityFunction(x, 0, 3)/3 + SingularityFunction(x, 10, 3)
+ 60*SingularityFunction(x, 30, 2) + SingularityFunction(x, 30, 3)/3 - 12000)/(E*I)
"""
x = self.variable
E = self.elastic_modulus
I = self.second_moment
if self._composite_type == "hinge":
return self._hinge_beam_deflection
if not self._boundary_conditions['deflection'] and not self._boundary_conditions['slope']:
if isinstance(I, Piecewise) and self._composite_type == "fixed":
args = I.args
prev_slope = 0
prev_def = 0
prev_end = 0
deflection = 0
for i in range(len(args)):
if i != 0:
prev_end = args[i-1][1].args[1]
slope_value = -S.One/E*integrate(self.bending_moment()/args[i][0], (x, prev_end, x))
recent_segment_slope = prev_slope + slope_value
deflection_value = integrate(recent_segment_slope, (x, prev_end, x))
if i != len(args) - 1:
deflection += (prev_def + deflection_value)*SingularityFunction(x, prev_end, 0) \
- (prev_def + deflection_value)*SingularityFunction(x, args[i][1].args[1], 0)
else:
deflection += (prev_def + deflection_value)*SingularityFunction(x, prev_end, 0)
prev_slope = slope_value.subs(x, args[i][1].args[1])
prev_def = deflection_value.subs(x, args[i][1].args[1])
return deflection
base_char = self._base_char
constants = symbols(base_char + '3:5')
return S.One/(E*I)*integrate(-integrate(self.bending_moment(), x), x) + constants[0]*x + constants[1]
elif not self._boundary_conditions['deflection']:
base_char = self._base_char
constant = symbols(base_char + '4')
return integrate(self.slope(), x) + constant
elif not self._boundary_conditions['slope'] and self._boundary_conditions['deflection']:
if isinstance(I, Piecewise) and self._composite_type == "fixed":
args = I.args
prev_slope = 0
prev_def = 0
prev_end = 0
deflection = 0
for i in range(len(args)):
if i != 0:
prev_end = args[i-1][1].args[1]
slope_value = -S.One/E*integrate(self.bending_moment()/args[i][0], (x, prev_end, x))
recent_segment_slope = prev_slope + slope_value
deflection_value = integrate(recent_segment_slope, (x, prev_end, x))
if i != len(args) - 1:
deflection += (prev_def + deflection_value)*SingularityFunction(x, prev_end, 0) \
- (prev_def + deflection_value)*SingularityFunction(x, args[i][1].args[1], 0)
else:
deflection += (prev_def + deflection_value)*SingularityFunction(x, prev_end, 0)
prev_slope = slope_value.subs(x, args[i][1].args[1])
prev_def = deflection_value.subs(x, args[i][1].args[1])
return deflection
base_char = self._base_char
C3, C4 = symbols(base_char + '3:5') # Integration constants
slope_curve = -integrate(self.bending_moment(), x) + C3
deflection_curve = integrate(slope_curve, x) + C4
bc_eqs = []
for position, value in self._boundary_conditions['deflection']:
eqs = deflection_curve.subs(x, position) - value
bc_eqs.append(eqs)
constants = list(linsolve(bc_eqs, (C3, C4)))
deflection_curve = deflection_curve.subs({C3: constants[0][0], C4: constants[0][1]})
return S.One/(E*I)*deflection_curve
if isinstance(I, Piecewise) and self._composite_type == "fixed":
args = I.args
prev_slope = 0
prev_def = 0
prev_end = 0
deflection = 0
for i in range(len(args)):
if i != 0:
prev_end = args[i-1][1].args[1]
slope_value = S.One/E*integrate(self.bending_moment()/args[i][0], (x, prev_end, x))
recent_segment_slope = prev_slope + slope_value
deflection_value = integrate(recent_segment_slope, (x, prev_end, x))
if i != len(args) - 1:
deflection += (prev_def + deflection_value)*SingularityFunction(x, prev_end, 0) \
- (prev_def + deflection_value)*SingularityFunction(x, args[i][1].args[1], 0)
else:
deflection += (prev_def + deflection_value)*SingularityFunction(x, prev_end, 0)
prev_slope = slope_value.subs(x, args[i][1].args[1])
prev_def = deflection_value.subs(x, args[i][1].args[1])
return deflection
C4 = Symbol('C4')
deflection_curve = integrate(self.slope(), x) + C4
bc_eqs = []
for position, value in self._boundary_conditions['deflection']:
eqs = deflection_curve.subs(x, position) - value
bc_eqs.append(eqs)
constants = list(linsolve(bc_eqs, C4))
deflection_curve = deflection_curve.subs({C4: constants[0][0]})
return deflection_curve
def max_deflection(self):
"""
Returns point of max deflection and its corresponding deflection value
in a Beam object.
"""
# To restrict the range within length of the Beam
slope_curve = Piecewise((float("nan"), self.variable<=0),
(self.slope(), self.variable<self.length),
(float("nan"), True))
points = solve(slope_curve.rewrite(Piecewise), self.variable,
domain=S.Reals)
deflection_curve = self.deflection()
deflections = [deflection_curve.subs(self.variable, x) for x in points]
deflections = list(map(abs, deflections))
if len(deflections) != 0:
max_def = max(deflections)
return (points[deflections.index(max_def)], max_def)
else:
return None
def shear_stress(self):
"""
Returns an expression representing the Shear Stress
curve of the Beam object.
"""
return self.shear_force()/self._area
def plot_shear_stress(self, subs=None):
"""
Returns a plot of shear stress present in the beam object.
Parameters
==========
subs : dictionary
Python dictionary containing Symbols as key and their
corresponding values.
Examples
========
There is a beam of length 8 meters and area of cross section 2 square
meters. A constant distributed load of 10 KN/m is applied from half of
the beam till the end. There are two simple supports below the beam,
one at the starting point and another at the ending point of the beam.
A pointload of magnitude 5 KN is also applied from top of the
beam, at a distance of 4 meters from the starting point.
Take E = 200 GPa and I = 400*(10**-6) meter**4.
Using the sign convention of downwards forces being positive.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy.physics.continuum_mechanics.beam import Beam
>>> from sympy import symbols
>>> R1, R2 = symbols('R1, R2')
>>> b = Beam(8, 200*(10**9), 400*(10**-6), 2)
>>> b.apply_load(5000, 2, -1)
>>> b.apply_load(R1, 0, -1)
>>> b.apply_load(R2, 8, -1)
>>> b.apply_load(10000, 4, 0, end=8)
>>> b.bc_deflection = [(0, 0), (8, 0)]
>>> b.solve_for_reaction_loads(R1, R2)
>>> b.plot_shear_stress()
Plot object containing:
[0]: cartesian line: 6875*SingularityFunction(x, 0, 0) - 2500*SingularityFunction(x, 2, 0)
- 5000*SingularityFunction(x, 4, 1) + 15625*SingularityFunction(x, 8, 0)
+ 5000*SingularityFunction(x, 8, 1) for x over (0.0, 8.0)
"""
shear_stress = self.shear_stress()
x = self.variable
length = self.length
if subs is None:
subs = {}
for sym in shear_stress.atoms(Symbol):
if sym != x and sym not in subs:
raise ValueError('value of %s was not passed.' %sym)
if length in subs:
length = subs[length]
# Returns Plot of Shear Stress
return plot (shear_stress.subs(subs), (x, 0, length),
title='Shear Stress', xlabel=r'$\mathrm{x}$', ylabel=r'$\tau$',
line_color='r')
def plot_shear_force(self, subs=None):
"""
Returns a plot for Shear force present in the Beam object.
Parameters
==========
subs : dictionary
Python dictionary containing Symbols as key and their
corresponding values.
Examples
========
There is a beam of length 8 meters. A constant distributed load of 10 KN/m
is applied from half of the beam till the end. There are two simple supports
below the beam, one at the starting point and another at the ending point
of the beam. A pointload of magnitude 5 KN is also applied from top of the
beam, at a distance of 4 meters from the starting point.
Take E = 200 GPa and I = 400*(10**-6) meter**4.
Using the sign convention of downwards forces being positive.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy.physics.continuum_mechanics.beam import Beam
>>> from sympy import symbols
>>> R1, R2 = symbols('R1, R2')
>>> b = Beam(8, 200*(10**9), 400*(10**-6))
>>> b.apply_load(5000, 2, -1)
>>> b.apply_load(R1, 0, -1)
>>> b.apply_load(R2, 8, -1)
>>> b.apply_load(10000, 4, 0, end=8)
>>> b.bc_deflection = [(0, 0), (8, 0)]
>>> b.solve_for_reaction_loads(R1, R2)
>>> b.plot_shear_force()
Plot object containing:
[0]: cartesian line: 13750*SingularityFunction(x, 0, 0) - 5000*SingularityFunction(x, 2, 0)
- 10000*SingularityFunction(x, 4, 1) + 31250*SingularityFunction(x, 8, 0)
+ 10000*SingularityFunction(x, 8, 1) for x over (0.0, 8.0)
"""
shear_force = self.shear_force()
if subs is None:
subs = {}
for sym in shear_force.atoms(Symbol):
if sym == self.variable:
continue
if sym not in subs:
raise ValueError('Value of %s was not passed.' %sym)
if self.length in subs:
length = subs[self.length]
else:
length = self.length
return plot(shear_force.subs(subs), (self.variable, 0, length), title='Shear Force',
xlabel=r'$\mathrm{x}$', ylabel=r'$\mathrm{V}$', line_color='g')
def plot_bending_moment(self, subs=None):
"""
Returns a plot for Bending moment present in the Beam object.
Parameters
==========
subs : dictionary
Python dictionary containing Symbols as key and their
corresponding values.
Examples
========
There is a beam of length 8 meters. A constant distributed load of 10 KN/m
is applied from half of the beam till the end. There are two simple supports
below the beam, one at the starting point and another at the ending point
of the beam. A pointload of magnitude 5 KN is also applied from top of the
beam, at a distance of 4 meters from the starting point.
Take E = 200 GPa and I = 400*(10**-6) meter**4.
Using the sign convention of downwards forces being positive.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy.physics.continuum_mechanics.beam import Beam
>>> from sympy import symbols
>>> R1, R2 = symbols('R1, R2')
>>> b = Beam(8, 200*(10**9), 400*(10**-6))
>>> b.apply_load(5000, 2, -1)
>>> b.apply_load(R1, 0, -1)
>>> b.apply_load(R2, 8, -1)
>>> b.apply_load(10000, 4, 0, end=8)
>>> b.bc_deflection = [(0, 0), (8, 0)]
>>> b.solve_for_reaction_loads(R1, R2)
>>> b.plot_bending_moment()
Plot object containing:
[0]: cartesian line: 13750*SingularityFunction(x, 0, 1) - 5000*SingularityFunction(x, 2, 1)
- 5000*SingularityFunction(x, 4, 2) + 31250*SingularityFunction(x, 8, 1)
+ 5000*SingularityFunction(x, 8, 2) for x over (0.0, 8.0)
"""
bending_moment = self.bending_moment()
if subs is None:
subs = {}
for sym in bending_moment.atoms(Symbol):
if sym == self.variable:
continue
if sym not in subs:
raise ValueError('Value of %s was not passed.' %sym)
if self.length in subs:
length = subs[self.length]
else:
length = self.length
return plot(bending_moment.subs(subs), (self.variable, 0, length), title='Bending Moment',
xlabel=r'$\mathrm{x}$', ylabel=r'$\mathrm{M}$', line_color='b')
def plot_slope(self, subs=None):
"""
Returns a plot for slope of deflection curve of the Beam object.
Parameters
==========
subs : dictionary
Python dictionary containing Symbols as key and their
corresponding values.
Examples
========
There is a beam of length 8 meters. A constant distributed load of 10 KN/m
is applied from half of the beam till the end. There are two simple supports
below the beam, one at the starting point and another at the ending point
of the beam. A pointload of magnitude 5 KN is also applied from top of the
beam, at a distance of 4 meters from the starting point.
Take E = 200 GPa and I = 400*(10**-6) meter**4.
Using the sign convention of downwards forces being positive.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy.physics.continuum_mechanics.beam import Beam
>>> from sympy import symbols
>>> R1, R2 = symbols('R1, R2')
>>> b = Beam(8, 200*(10**9), 400*(10**-6))
>>> b.apply_load(5000, 2, -1)
>>> b.apply_load(R1, 0, -1)
>>> b.apply_load(R2, 8, -1)
>>> b.apply_load(10000, 4, 0, end=8)
>>> b.bc_deflection = [(0, 0), (8, 0)]
>>> b.solve_for_reaction_loads(R1, R2)
>>> b.plot_slope()
Plot object containing:
[0]: cartesian line: -8.59375e-5*SingularityFunction(x, 0, 2) + 3.125e-5*SingularityFunction(x, 2, 2)
+ 2.08333333333333e-5*SingularityFunction(x, 4, 3) - 0.0001953125*SingularityFunction(x, 8, 2)
- 2.08333333333333e-5*SingularityFunction(x, 8, 3) + 0.00138541666666667 for x over (0.0, 8.0)
"""
slope = self.slope()
if subs is None:
subs = {}
for sym in slope.atoms(Symbol):
if sym == self.variable:
continue
if sym not in subs:
raise ValueError('Value of %s was not passed.' %sym)
if self.length in subs:
length = subs[self.length]
else:
length = self.length
return plot(slope.subs(subs), (self.variable, 0, length), title='Slope',
xlabel=r'$\mathrm{x}$', ylabel=r'$\theta$', line_color='m')
def plot_deflection(self, subs=None):
"""
Returns a plot for deflection curve of the Beam object.
Parameters
==========
subs : dictionary
Python dictionary containing Symbols as key and their
corresponding values.
Examples
========
There is a beam of length 8 meters. A constant distributed load of 10 KN/m
is applied from half of the beam till the end. There are two simple supports
below the beam, one at the starting point and another at the ending point
of the beam. A pointload of magnitude 5 KN is also applied from top of the
beam, at a distance of 4 meters from the starting point.
Take E = 200 GPa and I = 400*(10**-6) meter**4.
Using the sign convention of downwards forces being positive.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy.physics.continuum_mechanics.beam import Beam
>>> from sympy import symbols
>>> R1, R2 = symbols('R1, R2')
>>> b = Beam(8, 200*(10**9), 400*(10**-6))
>>> b.apply_load(5000, 2, -1)
>>> b.apply_load(R1, 0, -1)
>>> b.apply_load(R2, 8, -1)
>>> b.apply_load(10000, 4, 0, end=8)
>>> b.bc_deflection = [(0, 0), (8, 0)]
>>> b.solve_for_reaction_loads(R1, R2)
>>> b.plot_deflection()
Plot object containing:
[0]: cartesian line: 0.00138541666666667*x - 2.86458333333333e-5*SingularityFunction(x, 0, 3)
+ 1.04166666666667e-5*SingularityFunction(x, 2, 3) + 5.20833333333333e-6*SingularityFunction(x, 4, 4)
- 6.51041666666667e-5*SingularityFunction(x, 8, 3) - 5.20833333333333e-6*SingularityFunction(x, 8, 4)
for x over (0.0, 8.0)
"""
deflection = self.deflection()
if subs is None:
subs = {}
for sym in deflection.atoms(Symbol):
if sym == self.variable:
continue
if sym not in subs:
raise ValueError('Value of %s was not passed.' %sym)
if self.length in subs:
length = subs[self.length]
else:
length = self.length
return plot(deflection.subs(subs), (self.variable, 0, length),
title='Deflection', xlabel=r'$\mathrm{x}$', ylabel=r'$\delta$',
line_color='r')
def plot_loading_results(self, subs=None):
"""
Returns a subplot of Shear Force, Bending Moment,
Slope and Deflection of the Beam object.
Parameters
==========
subs : dictionary
Python dictionary containing Symbols as key and their
corresponding values.
Examples
========
There is a beam of length 8 meters. A constant distributed load of 10 KN/m
is applied from half of the beam till the end. There are two simple supports
below the beam, one at the starting point and another at the ending point
of the beam. A pointload of magnitude 5 KN is also applied from top of the
beam, at a distance of 4 meters from the starting point.
Take E = 200 GPa and I = 400*(10**-6) meter**4.
Using the sign convention of downwards forces being positive.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy.physics.continuum_mechanics.beam import Beam
>>> from sympy import symbols
>>> R1, R2 = symbols('R1, R2')
>>> b = Beam(8, 200*(10**9), 400*(10**-6))
>>> b.apply_load(5000, 2, -1)
>>> b.apply_load(R1, 0, -1)
>>> b.apply_load(R2, 8, -1)
>>> b.apply_load(10000, 4, 0, end=8)
>>> b.bc_deflection = [(0, 0), (8, 0)]
>>> b.solve_for_reaction_loads(R1, R2)
>>> axes = b.plot_loading_results()
"""
length = self.length
variable = self.variable
if subs is None:
subs = {}
for sym in self.deflection().atoms(Symbol):
if sym == self.variable:
continue
if sym not in subs:
raise ValueError('Value of %s was not passed.' %sym)
if length in subs:
length = subs[length]
ax1 = plot(self.shear_force().subs(subs), (variable, 0, length),
title="Shear Force", xlabel=r'$\mathrm{x}$', ylabel=r'$\mathrm{V}$',
line_color='g', show=False)
ax2 = plot(self.bending_moment().subs(subs), (variable, 0, length),
title="Bending Moment", xlabel=r'$\mathrm{x}$', ylabel=r'$\mathrm{M}$',
line_color='b', show=False)
ax3 = plot(self.slope().subs(subs), (variable, 0, length),
title="Slope", xlabel=r'$\mathrm{x}$', ylabel=r'$\theta$',
line_color='m', show=False)
ax4 = plot(self.deflection().subs(subs), (variable, 0, length),
title="Deflection", xlabel=r'$\mathrm{x}$', ylabel=r'$\delta$',
line_color='r', show=False)
return PlotGrid(4, 1, ax1, ax2, ax3, ax4)
def _solve_for_ild_equations(self):
"""
Helper function for I.L.D. It takes the unsubstituted
copy of the load equation and uses it to calculate shear force and bending
moment equations.
"""
x = self.variable
shear_force = -integrate(self._original_load, x)
bending_moment = integrate(shear_force, x)
return shear_force, bending_moment
def solve_for_ild_reactions(self, value, *reactions):
"""
Determines the Influence Line Diagram equations for reaction
forces under the effect of a moving load.
Parameters
==========
value : Integer
Magnitude of moving load
reactions :
The reaction forces applied on the beam.
Examples
========
There is a beam of length 10 meters. There are two simple supports
below the beam, one at the starting point and another at the ending
point of the beam. Calculate the I.L.D. equations for reaction forces
under the effect of a moving load of magnitude 1kN.
Using the sign convention of downwards forces being positive.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy import symbols
>>> from sympy.physics.continuum_mechanics.beam import Beam
>>> E, I = symbols('E, I')
>>> R_0, R_10 = symbols('R_0, R_10')
>>> b = Beam(10, E, I)
>>> p0 = b.apply_support(0, 'roller')
>>> p10 = b.apply_support(10, 'roller')
>>> b.solve_for_ild_reactions(1,R_0,R_10)
>>> b.ild_reactions
{R_0: x/10 - 1, R_10: -x/10}
"""
shear_force, bending_moment = self._solve_for_ild_equations()
x = self.variable
l = self.length
C3 = Symbol('C3')
C4 = Symbol('C4')
shear_curve = limit(shear_force, x, l) - value
moment_curve = limit(bending_moment, x, l) - value*(l-x)
slope_eqs = []
deflection_eqs = []
slope_curve = integrate(bending_moment, x) + C3
for position, value in self._boundary_conditions['slope']:
eqs = slope_curve.subs(x, position) - value
slope_eqs.append(eqs)
deflection_curve = integrate(slope_curve, x) + C4
for position, value in self._boundary_conditions['deflection']:
eqs = deflection_curve.subs(x, position) - value
deflection_eqs.append(eqs)
solution = list((linsolve([shear_curve, moment_curve] + slope_eqs
+ deflection_eqs, (C3, C4) + reactions).args)[0])
solution = solution[2:]
# Determining the equations and solving them.
self._ild_reactions = dict(zip(reactions, solution))
def plot_ild_reactions(self, subs=None):
"""
Plots the Influence Line Diagram of Reaction Forces
under the effect of a moving load. This function
should be called after calling solve_for_ild_reactions().
Parameters
==========
subs : dictionary
Python dictionary containing Symbols as key and their
corresponding values.
Examples
========
There is a beam of length 10 meters. A point load of magnitude 5KN
is also applied from top of the beam, at a distance of 4 meters
from the starting point. There are two simple supports below the
beam, located at the starting point and at a distance of 7 meters
from the starting point. Plot the I.L.D. equations for reactions
at both support points under the effect of a moving load
of magnitude 1kN.
Using the sign convention of downwards forces being positive.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy import symbols
>>> from sympy.physics.continuum_mechanics.beam import Beam
>>> E, I = symbols('E, I')
>>> R_0, R_7 = symbols('R_0, R_7')
>>> b = Beam(10, E, I)
>>> p0 = b.apply_support(0, 'roller')
>>> p7 = b.apply_support(7, 'roller')
>>> b.apply_load(5,4,-1)
>>> b.solve_for_ild_reactions(1,R_0,R_7)
>>> b.ild_reactions
{R_0: x/7 - 22/7, R_7: -x/7 - 20/7}
>>> b.plot_ild_reactions()
PlotGrid object containing:
Plot[0]:Plot object containing:
[0]: cartesian line: x/7 - 22/7 for x over (0.0, 10.0)
Plot[1]:Plot object containing:
[0]: cartesian line: -x/7 - 20/7 for x over (0.0, 10.0)
"""
if not self._ild_reactions:
raise ValueError("I.L.D. reaction equations not found. Please use solve_for_ild_reactions() to generate the I.L.D. reaction equations.")
x = self.variable
ildplots = []
if subs is None:
subs = {}
for reaction in self._ild_reactions:
for sym in self._ild_reactions[reaction].atoms(Symbol):
if sym != x and sym not in subs:
raise ValueError('Value of %s was not passed.' %sym)
for sym in self._length.atoms(Symbol):
if sym != x and sym not in subs:
raise ValueError('Value of %s was not passed.' %sym)
for reaction in self._ild_reactions:
ildplots.append(plot(self._ild_reactions[reaction].subs(subs),
(x, 0, self._length.subs(subs)), title='I.L.D. for Reactions',
xlabel=x, ylabel=reaction, line_color='blue', show=False))
return PlotGrid(len(ildplots), 1, *ildplots)
def solve_for_ild_shear(self, distance, value, *reactions):
"""
Determines the Influence Line Diagram equations for shear at a
specified point under the effect of a moving load.
Parameters
==========
distance : Integer
Distance of the point from the start of the beam
for which equations are to be determined
value : Integer
Magnitude of moving load
reactions :
The reaction forces applied on the beam.
Examples
========
There is a beam of length 12 meters. There are two simple supports
below the beam, one at the starting point and another at a distance
of 8 meters. Calculate the I.L.D. equations for Shear at a distance
of 4 meters under the effect of a moving load of magnitude 1kN.
Using the sign convention of downwards forces being positive.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy import symbols
>>> from sympy.physics.continuum_mechanics.beam import Beam
>>> E, I = symbols('E, I')
>>> R_0, R_8 = symbols('R_0, R_8')
>>> b = Beam(12, E, I)
>>> p0 = b.apply_support(0, 'roller')
>>> p8 = b.apply_support(8, 'roller')
>>> b.solve_for_ild_reactions(1, R_0, R_8)
>>> b.solve_for_ild_shear(4, 1, R_0, R_8)
>>> b.ild_shear
Piecewise((x/8, x < 4), (x/8 - 1, x > 4))
"""
x = self.variable
l = self.length
shear_force, _ = self._solve_for_ild_equations()
shear_curve1 = value - limit(shear_force, x, distance)
shear_curve2 = (limit(shear_force, x, l) - limit(shear_force, x, distance)) - value
for reaction in reactions:
shear_curve1 = shear_curve1.subs(reaction,self._ild_reactions[reaction])
shear_curve2 = shear_curve2.subs(reaction,self._ild_reactions[reaction])
shear_eq = Piecewise((shear_curve1, x < distance), (shear_curve2, x > distance))
self._ild_shear = shear_eq
def plot_ild_shear(self,subs=None):
"""
Plots the Influence Line Diagram for Shear under the effect
of a moving load. This function should be called after
calling solve_for_ild_shear().
Parameters
==========
subs : dictionary
Python dictionary containing Symbols as key and their
corresponding values.
Examples
========
There is a beam of length 12 meters. There are two simple supports
below the beam, one at the starting point and another at a distance
of 8 meters. Plot the I.L.D. for Shear at a distance
of 4 meters under the effect of a moving load of magnitude 1kN.
Using the sign convention of downwards forces being positive.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy import symbols
>>> from sympy.physics.continuum_mechanics.beam import Beam
>>> E, I = symbols('E, I')
>>> R_0, R_8 = symbols('R_0, R_8')
>>> b = Beam(12, E, I)
>>> p0 = b.apply_support(0, 'roller')
>>> p8 = b.apply_support(8, 'roller')
>>> b.solve_for_ild_reactions(1, R_0, R_8)
>>> b.solve_for_ild_shear(4, 1, R_0, R_8)
>>> b.ild_shear
Piecewise((x/8, x < 4), (x/8 - 1, x > 4))
>>> b.plot_ild_shear()
Plot object containing:
[0]: cartesian line: Piecewise((x/8, x < 4), (x/8 - 1, x > 4)) for x over (0.0, 12.0)
"""
if not self._ild_shear:
raise ValueError("I.L.D. shear equation not found. Please use solve_for_ild_shear() to generate the I.L.D. shear equations.")
x = self.variable
l = self._length
if subs is None:
subs = {}
for sym in self._ild_shear.atoms(Symbol):
if sym != x and sym not in subs:
raise ValueError('Value of %s was not passed.' %sym)
for sym in self._length.atoms(Symbol):
if sym != x and sym not in subs:
raise ValueError('Value of %s was not passed.' %sym)
return plot(self._ild_shear.subs(subs), (x, 0, l), title='I.L.D. for Shear',
xlabel=r'$\mathrm{X}$', ylabel=r'$\mathrm{V}$', line_color='blue',show=True)
def solve_for_ild_moment(self, distance, value, *reactions):
"""
Determines the Influence Line Diagram equations for moment at a
specified point under the effect of a moving load.
Parameters
==========
distance : Integer
Distance of the point from the start of the beam
for which equations are to be determined
value : Integer
Magnitude of moving load
reactions :
The reaction forces applied on the beam.
Examples
========
There is a beam of length 12 meters. There are two simple supports
below the beam, one at the starting point and another at a distance
of 8 meters. Calculate the I.L.D. equations for Moment at a distance
of 4 meters under the effect of a moving load of magnitude 1kN.
Using the sign convention of downwards forces being positive.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy import symbols
>>> from sympy.physics.continuum_mechanics.beam import Beam
>>> E, I = symbols('E, I')
>>> R_0, R_8 = symbols('R_0, R_8')
>>> b = Beam(12, E, I)
>>> p0 = b.apply_support(0, 'roller')
>>> p8 = b.apply_support(8, 'roller')
>>> b.solve_for_ild_reactions(1, R_0, R_8)
>>> b.solve_for_ild_moment(4, 1, R_0, R_8)
>>> b.ild_moment
Piecewise((-x/2, x < 4), (x/2 - 4, x > 4))
"""
x = self.variable
l = self.length
_, moment = self._solve_for_ild_equations()
moment_curve1 = value*(distance-x) - limit(moment, x, distance)
moment_curve2= (limit(moment, x, l)-limit(moment, x, distance))-value*(l-x)
for reaction in reactions:
moment_curve1 = moment_curve1.subs(reaction, self._ild_reactions[reaction])
moment_curve2 = moment_curve2.subs(reaction, self._ild_reactions[reaction])
moment_eq = Piecewise((moment_curve1, x < distance), (moment_curve2, x > distance))
self._ild_moment = moment_eq
def plot_ild_moment(self,subs=None):
"""
Plots the Influence Line Diagram for Moment under the effect
of a moving load. This function should be called after
calling solve_for_ild_moment().
Parameters
==========
subs : dictionary
Python dictionary containing Symbols as key and their
corresponding values.
Examples
========
There is a beam of length 12 meters. There are two simple supports
below the beam, one at the starting point and another at a distance
of 8 meters. Plot the I.L.D. for Moment at a distance
of 4 meters under the effect of a moving load of magnitude 1kN.
Using the sign convention of downwards forces being positive.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy import symbols
>>> from sympy.physics.continuum_mechanics.beam import Beam
>>> E, I = symbols('E, I')
>>> R_0, R_8 = symbols('R_0, R_8')
>>> b = Beam(12, E, I)
>>> p0 = b.apply_support(0, 'roller')
>>> p8 = b.apply_support(8, 'roller')
>>> b.solve_for_ild_reactions(1, R_0, R_8)
>>> b.solve_for_ild_moment(4, 1, R_0, R_8)
>>> b.ild_moment
Piecewise((-x/2, x < 4), (x/2 - 4, x > 4))
>>> b.plot_ild_moment()
Plot object containing:
[0]: cartesian line: Piecewise((-x/2, x < 4), (x/2 - 4, x > 4)) for x over (0.0, 12.0)
"""
if not self._ild_moment:
raise ValueError("I.L.D. moment equation not found. Please use solve_for_ild_moment() to generate the I.L.D. moment equations.")
x = self.variable
if subs is None:
subs = {}
for sym in self._ild_moment.atoms(Symbol):
if sym != x and sym not in subs:
raise ValueError('Value of %s was not passed.' %sym)
for sym in self._length.atoms(Symbol):
if sym != x and sym not in subs:
raise ValueError('Value of %s was not passed.' %sym)
return plot(self._ild_moment.subs(subs), (x, 0, self._length), title='I.L.D. for Moment',
xlabel=r'$\mathrm{X}$', ylabel=r'$\mathrm{M}$', line_color='blue', show=True)
@doctest_depends_on(modules=('numpy',))
def draw(self, pictorial=True):
"""
Returns a plot object representing the beam diagram of the beam.
In particular, the diagram might include:
* the beam.
* vertical black arrows represent point loads and support reaction
forces (the latter if they have been added with the ``apply_load``
method).
* circular arrows represent moments.
* shaded areas represent distributed loads.
* the support, if ``apply_support`` has been executed.
* if a composite beam has been created with the ``join`` method and
a hinge has been specified, it will be shown with a white disc.
The diagram shows positive loads on the upper side of the beam,
and negative loads on the lower side. If two or more distributed
loads acts along the same direction over the same region, the
function will add them up together.
.. note::
The user must be careful while entering load values.
The draw function assumes a sign convention which is used
for plotting loads.
Given a right handed coordinate system with XYZ coordinates,
the beam's length is assumed to be along the positive X axis.
The draw function recognizes positive loads(with n>-2) as loads
acting along negative Y direction and positive moments acting
along positive Z direction.
Parameters
==========
pictorial: Boolean (default=True)
Setting ``pictorial=True`` would simply create a pictorial (scaled)
view of the beam diagram. On the other hand, ``pictorial=False``
would create a beam diagram with the exact dimensions on the plot.
Examples
========
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy.physics.continuum_mechanics.beam import Beam
>>> from sympy import symbols
>>> P1, P2, M = symbols('P1, P2, M')
>>> E, I = symbols('E, I')
>>> b = Beam(50, 20, 30)
>>> b.apply_load(-10, 2, -1)
>>> b.apply_load(15, 26, -1)
>>> b.apply_load(P1, 10, -1)
>>> b.apply_load(-P2, 40, -1)
>>> b.apply_load(90, 5, 0, 23)
>>> b.apply_load(10, 30, 1, 50)
>>> b.apply_load(M, 15, -2)
>>> b.apply_load(-M, 30, -2)
>>> p50 = b.apply_support(50, "pin")
>>> p0, m0 = b.apply_support(0, "fixed")
>>> p20 = b.apply_support(20, "roller")
>>> p = b.draw() # doctest: +SKIP
>>> p # doctest: +ELLIPSIS,+SKIP
Plot object containing:
[0]: cartesian line: 25*SingularityFunction(x, 5, 0) - 25*SingularityFunction(x, 23, 0)
+ SingularityFunction(x, 30, 1) - 20*SingularityFunction(x, 50, 0)
- SingularityFunction(x, 50, 1) + 5 for x over (0.0, 50.0)
[1]: cartesian line: 5 for x over (0.0, 50.0)
...
>>> p.show() # doctest: +SKIP
"""
if not numpy:
raise ImportError("To use this function numpy module is required")
loads = list(set(self.applied_loads) - set(self._support_as_loads))
if (not pictorial) and any((len(l[0].free_symbols) > 0) and (l[2] >= 0) for l in loads):
raise ValueError("`pictorial=False` requires numerical "
"distributed loads. Instead, symbolic loads were found. "
"Cannot continue.")
x = self.variable
# checking whether length is an expression in terms of any Symbol.
if isinstance(self.length, Expr):
l = list(self.length.atoms(Symbol))
# assigning every Symbol a default value of 10
l = dict.fromkeys(l, 10)
length = self.length.subs(l)
else:
l = {}
length = self.length
height = length/10
rectangles = []
rectangles.append({'xy':(0, 0), 'width':length, 'height': height, 'facecolor':"brown"})
annotations, markers, load_eq,load_eq1, fill = self._draw_load(pictorial, length, l)
support_markers, support_rectangles = self._draw_supports(length, l)
rectangles += support_rectangles
markers += support_markers
if self._composite_type == "hinge":
# if self is a composite beam with an hinge, show it
ratio = self._hinge_position / self.length
x_pos = float(ratio) * length
markers += [{'args':[[x_pos], [height / 2]], 'marker':'o', 'markersize':6, 'color':"white"}]
ylim = (-length, 1.25*length)
if fill:
# when distributed loads are presents, they might get clipped out
# in the figure by the ylim settings.
# It might be necessary to compute new limits.
_min = min(min(fill["y2"]), min(r["xy"][1] for r in rectangles))
_max = max(max(fill["y1"]), max(r["xy"][1] for r in rectangles))
if (_min < ylim[0]) or (_max > ylim[1]):
offset = abs(_max - _min) * 0.1
ylim = (_min - offset, _max + offset)
sing_plot = plot(height + load_eq, height + load_eq1, (x, 0, length),
xlim=(-height, length + height), ylim=ylim,
annotations=annotations, markers=markers, rectangles=rectangles,
line_color='brown', fill=fill, axis=False, show=False)
return sing_plot
def _is_load_negative(self, load):
"""Try to determine if a load is negative or positive, using
expansion and doit if necessary.
Returns
=======
True: if the load is negative
False: if the load is positive
None: if it is indeterminate
"""
rv = load.is_negative
if load.is_Atom or rv is not None:
return rv
return load.doit().expand().is_negative
def _draw_load(self, pictorial, length, l):
loads = list(set(self.applied_loads) - set(self._support_as_loads))
height = length/10
x = self.variable
annotations = []
markers = []
load_args = []
scaled_load = 0
load_args1 = []
scaled_load1 = 0
load_eq = S.Zero # For positive valued higher order loads
load_eq1 = S.Zero # For negative valued higher order loads
fill = None
# schematic view should use the class convention as much as possible.
# However, users can add expressions as symbolic loads, for example
# P1 - P2: is this load positive or negative? We can't say.
# On these occasions it is better to inform users about the
# indeterminate state of those loads.
warning_head = "Please, note that this schematic view might not be " \
"in agreement with the sign convention used by the Beam class " \
"for load-related computations, because it was not possible " \
"to determine the sign (hence, the direction) of the " \
"following loads:\n"
warning_body = ""
for load in loads:
# check if the position of load is in terms of the beam length.
if l:
pos = load[1].subs(l)
else:
pos = load[1]
# point loads
if load[2] == -1:
iln = self._is_load_negative(load[0])
if iln is None:
warning_body += "* Point load %s located at %s\n" % (load[0], load[1])
if iln:
annotations.append({'text':'', 'xy':(pos, 0), 'xytext':(pos, height - 4*height), 'arrowprops':{'width': 1.5, 'headlength': 5, 'headwidth': 5, 'facecolor': 'black'}})
else:
annotations.append({'text':'', 'xy':(pos, height), 'xytext':(pos, height*4), 'arrowprops':{"width": 1.5, "headlength": 4, "headwidth": 4, "facecolor": 'black'}})
# moment loads
elif load[2] == -2:
iln = self._is_load_negative(load[0])
if iln is None:
warning_body += "* Moment %s located at %s\n" % (load[0], load[1])
if self._is_load_negative(load[0]):
markers.append({'args':[[pos], [height/2]], 'marker': r'$\circlearrowright$', 'markersize':15})
else:
markers.append({'args':[[pos], [height/2]], 'marker': r'$\circlearrowleft$', 'markersize':15})
# higher order loads
elif load[2] >= 0:
# `fill` will be assigned only when higher order loads are present
value, start, order, end = load
iln = self._is_load_negative(value)
if iln is None:
warning_body += "* Distributed load %s from %s to %s\n" % (value, start, end)
# Positive loads have their separate equations
if not iln:
# if pictorial is True we remake the load equation again with
# some constant magnitude values.
if pictorial:
# remake the load equation again with some constant
# magnitude values.
value = 10**(1-order) if order > 0 else length/2
scaled_load += value*SingularityFunction(x, start, order)
if end:
f2 = value*x**order if order >= 0 else length/2*x**order
for i in range(0, order + 1):
scaled_load -= (f2.diff(x, i).subs(x, end - start)*
SingularityFunction(x, end, i)/factorial(i))
if isinstance(scaled_load, Add):
load_args = scaled_load.args
else:
# when the load equation consists of only a single term
load_args = (scaled_load,)
load_eq = Add(*[i.subs(l) for i in load_args])
# For loads with negative value
else:
if pictorial:
# remake the load equation again with some constant
# magnitude values.
value = 10**(1-order) if order > 0 else length/2
scaled_load1 += abs(value)*SingularityFunction(x, start, order)
if end:
f2 = abs(value)*x**order if order >= 0 else length/2*x**order
for i in range(0, order + 1):
scaled_load1 -= (f2.diff(x, i).subs(x, end - start)*
SingularityFunction(x, end, i)/factorial(i))
if isinstance(scaled_load1, Add):
load_args1 = scaled_load1.args
else:
# when the load equation consists of only a single term
load_args1 = (scaled_load1,)
load_eq1 = [i.subs(l) for i in load_args1]
load_eq1 = -Add(*load_eq1) - height
if len(warning_body) > 0:
warnings.warn(warning_head + warning_body)
xx = numpy.arange(0, float(length), 0.001)
yy1 = lambdify([x], height + load_eq.rewrite(Piecewise))(xx)
yy2 = lambdify([x], height + load_eq1.rewrite(Piecewise))(xx)
if not isinstance(yy1, numpy.ndarray):
yy1 *= numpy.ones_like(xx)
if not isinstance(yy2, numpy.ndarray):
yy2 *= numpy.ones_like(xx)
fill = {'x': xx, 'y1': yy1, 'y2': yy2,
'color':'darkkhaki', "zorder": -1}
return annotations, markers, load_eq, load_eq1, fill
def _draw_supports(self, length, l):
height = float(length/10)
support_markers = []
support_rectangles = []
for support in self._applied_supports:
if l:
pos = support[0].subs(l)
else:
pos = support[0]
if support[1] == "pin":
support_markers.append({'args':[pos, [0]], 'marker':6, 'markersize':13, 'color':"black"})
elif support[1] == "roller":
support_markers.append({'args':[pos, [-height/2.5]], 'marker':'o', 'markersize':11, 'color':"black"})
elif support[1] == "fixed":
if pos == 0:
support_rectangles.append({'xy':(0, -3*height), 'width':-length/20, 'height':6*height + height, 'fill':False, 'hatch':'/////'})
else:
support_rectangles.append({'xy':(length, -3*height), 'width':length/20, 'height': 6*height + height, 'fill':False, 'hatch':'/////'})
return support_markers, support_rectangles
class Beam3D(Beam):
"""
This class handles loads applied in any direction of a 3D space along
with unequal values of Second moment along different axes.
.. note::
A consistent sign convention must be used while solving a beam
bending problem; the results will
automatically follow the chosen sign convention.
This class assumes that any kind of distributed load/moment is
applied through out the span of a beam.
Examples
========
There is a beam of l meters long. A constant distributed load of magnitude q
is applied along y-axis from start till the end of beam. A constant distributed
moment of magnitude m is also applied along z-axis from start till the end of beam.
Beam is fixed at both of its end. So, deflection of the beam at the both ends
is restricted.
>>> from sympy.physics.continuum_mechanics.beam import Beam3D
>>> from sympy import symbols, simplify, collect, factor
>>> l, E, G, I, A = symbols('l, E, G, I, A')
>>> b = Beam3D(l, E, G, I, A)
>>> x, q, m = symbols('x, q, m')
>>> b.apply_load(q, 0, 0, dir="y")
>>> b.apply_moment_load(m, 0, -1, dir="z")
>>> b.shear_force()
[0, -q*x, 0]
>>> b.bending_moment()
[0, 0, -m*x + q*x**2/2]
>>> b.bc_slope = [(0, [0, 0, 0]), (l, [0, 0, 0])]
>>> b.bc_deflection = [(0, [0, 0, 0]), (l, [0, 0, 0])]
>>> b.solve_slope_deflection()
>>> factor(b.slope())
[0, 0, x*(-l + x)*(-A*G*l**3*q + 2*A*G*l**2*q*x - 12*E*I*l*q
- 72*E*I*m + 24*E*I*q*x)/(12*E*I*(A*G*l**2 + 12*E*I))]
>>> dx, dy, dz = b.deflection()
>>> dy = collect(simplify(dy), x)
>>> dx == dz == 0
True
>>> dy == (x*(12*E*I*l*(A*G*l**2*q - 2*A*G*l*m + 12*E*I*q)
... + x*(A*G*l*(3*l*(A*G*l**2*q - 2*A*G*l*m + 12*E*I*q) + x*(-2*A*G*l**2*q + 4*A*G*l*m - 24*E*I*q))
... + A*G*(A*G*l**2 + 12*E*I)*(-2*l**2*q + 6*l*m - 4*m*x + q*x**2)
... - 12*E*I*q*(A*G*l**2 + 12*E*I)))/(24*A*E*G*I*(A*G*l**2 + 12*E*I)))
True
References
==========
.. [1] https://homes.civil.aau.dk/jc/FemteSemester/Beams3D.pdf
"""
def __init__(self, length, elastic_modulus, shear_modulus, second_moment,
area, variable=Symbol('x')):
"""Initializes the class.
Parameters
==========
length : Sympifyable
A Symbol or value representing the Beam's length.
elastic_modulus : Sympifyable
A SymPy expression representing the Beam's Modulus of Elasticity.
It is a measure of the stiffness of the Beam material.
shear_modulus : Sympifyable
A SymPy expression representing the Beam's Modulus of rigidity.
It is a measure of rigidity of the Beam material.
second_moment : Sympifyable or list
A list of two elements having SymPy expression representing the
Beam's Second moment of area. First value represent Second moment
across y-axis and second across z-axis.
Single SymPy expression can be passed if both values are same
area : Sympifyable
A SymPy expression representing the Beam's cross-sectional area
in a plane perpendicular to length of the Beam.
variable : Symbol, optional
A Symbol object that will be used as the variable along the beam
while representing the load, shear, moment, slope and deflection
curve. By default, it is set to ``Symbol('x')``.
"""
super().__init__(length, elastic_modulus, second_moment, variable)
self.shear_modulus = shear_modulus
self.area = area
self._load_vector = [0, 0, 0]
self._moment_load_vector = [0, 0, 0]
self._torsion_moment = {}
self._load_Singularity = [0, 0, 0]
self._slope = [0, 0, 0]
self._deflection = [0, 0, 0]
self._angular_deflection = 0
@property
def shear_modulus(self):
"""Young's Modulus of the Beam. """
return self._shear_modulus
@shear_modulus.setter
def shear_modulus(self, e):
self._shear_modulus = sympify(e)
@property
def second_moment(self):
"""Second moment of area of the Beam. """
return self._second_moment
@second_moment.setter
def second_moment(self, i):
if isinstance(i, list):
i = [sympify(x) for x in i]
self._second_moment = i
else:
self._second_moment = sympify(i)
@property
def area(self):
"""Cross-sectional area of the Beam. """
return self._area
@area.setter
def area(self, a):
self._area = sympify(a)
@property
def load_vector(self):
"""
Returns a three element list representing the load vector.
"""
return self._load_vector
@property
def moment_load_vector(self):
"""
Returns a three element list representing moment loads on Beam.
"""
return self._moment_load_vector
@property
def boundary_conditions(self):
"""
Returns a dictionary of boundary conditions applied on the beam.
The dictionary has two keywords namely slope and deflection.
The value of each keyword is a list of tuple, where each tuple
contains location and value of a boundary condition in the format
(location, value). Further each value is a list corresponding to
slope or deflection(s) values along three axes at that location.
Examples
========
There is a beam of length 4 meters. The slope at 0 should be 4 along
the x-axis and 0 along others. At the other end of beam, deflection
along all the three axes should be zero.
>>> from sympy.physics.continuum_mechanics.beam import Beam3D
>>> from sympy import symbols
>>> l, E, G, I, A, x = symbols('l, E, G, I, A, x')
>>> b = Beam3D(30, E, G, I, A, x)
>>> b.bc_slope = [(0, (4, 0, 0))]
>>> b.bc_deflection = [(4, [0, 0, 0])]
>>> b.boundary_conditions
{'deflection': [(4, [0, 0, 0])], 'slope': [(0, (4, 0, 0))]}
Here the deflection of the beam should be ``0`` along all the three axes at ``4``.
Similarly, the slope of the beam should be ``4`` along x-axis and ``0``
along y and z axis at ``0``.
"""
return self._boundary_conditions
def polar_moment(self):
"""
Returns the polar moment of area of the beam
about the X axis with respect to the centroid.
Examples
========
>>> from sympy.physics.continuum_mechanics.beam import Beam3D
>>> from sympy import symbols
>>> l, E, G, I, A = symbols('l, E, G, I, A')
>>> b = Beam3D(l, E, G, I, A)
>>> b.polar_moment()
2*I
>>> I1 = [9, 15]
>>> b = Beam3D(l, E, G, I1, A)
>>> b.polar_moment()
24
"""
if not iterable(self.second_moment):
return 2*self.second_moment
return sum(self.second_moment)
def apply_load(self, value, start, order, dir="y"):
"""
This method adds up the force load to a particular beam object.
Parameters
==========
value : Sympifyable
The magnitude of an applied load.
dir : String
Axis along which load is applied.
order : Integer
The order of the applied load.
- For point loads, order=-1
- For constant distributed load, order=0
- For ramp loads, order=1
- For parabolic ramp loads, order=2
- ... so on.
"""
x = self.variable
value = sympify(value)
start = sympify(start)
order = sympify(order)
if dir == "x":
if not order == -1:
self._load_vector[0] += value
self._load_Singularity[0] += value*SingularityFunction(x, start, order)
elif dir == "y":
if not order == -1:
self._load_vector[1] += value
self._load_Singularity[1] += value*SingularityFunction(x, start, order)
else:
if not order == -1:
self._load_vector[2] += value
self._load_Singularity[2] += value*SingularityFunction(x, start, order)
def apply_moment_load(self, value, start, order, dir="y"):
"""
This method adds up the moment loads to a particular beam object.
Parameters
==========
value : Sympifyable
The magnitude of an applied moment.
dir : String
Axis along which moment is applied.
order : Integer
The order of the applied load.
- For point moments, order=-2
- For constant distributed moment, order=-1
- For ramp moments, order=0
- For parabolic ramp moments, order=1
- ... so on.
"""
x = self.variable
value = sympify(value)
start = sympify(start)
order = sympify(order)
if dir == "x":
if not order == -2:
self._moment_load_vector[0] += value
else:
if start in list(self._torsion_moment):
self._torsion_moment[start] += value
else:
self._torsion_moment[start] = value
self._load_Singularity[0] += value*SingularityFunction(x, start, order)
elif dir == "y":
if not order == -2:
self._moment_load_vector[1] += value
self._load_Singularity[0] += value*SingularityFunction(x, start, order)
else:
if not order == -2:
self._moment_load_vector[2] += value
self._load_Singularity[0] += value*SingularityFunction(x, start, order)
def apply_support(self, loc, type="fixed"):
if type in ("pin", "roller"):
reaction_load = Symbol('R_'+str(loc))
self._reaction_loads[reaction_load] = reaction_load
self.bc_deflection.append((loc, [0, 0, 0]))
else:
reaction_load = Symbol('R_'+str(loc))
reaction_moment = Symbol('M_'+str(loc))
self._reaction_loads[reaction_load] = [reaction_load, reaction_moment]
self.bc_deflection.append((loc, [0, 0, 0]))
self.bc_slope.append((loc, [0, 0, 0]))
def solve_for_reaction_loads(self, *reaction):
"""
Solves for the reaction forces.
Examples
========
There is a beam of length 30 meters. It it supported by rollers at
of its end. A constant distributed load of magnitude 8 N is applied
from start till its end along y-axis. Another linear load having
slope equal to 9 is applied along z-axis.
>>> from sympy.physics.continuum_mechanics.beam import Beam3D
>>> from sympy import symbols
>>> l, E, G, I, A, x = symbols('l, E, G, I, A, x')
>>> b = Beam3D(30, E, G, I, A, x)
>>> b.apply_load(8, start=0, order=0, dir="y")
>>> b.apply_load(9*x, start=0, order=0, dir="z")
>>> b.bc_deflection = [(0, [0, 0, 0]), (30, [0, 0, 0])]
>>> R1, R2, R3, R4 = symbols('R1, R2, R3, R4')
>>> b.apply_load(R1, start=0, order=-1, dir="y")
>>> b.apply_load(R2, start=30, order=-1, dir="y")
>>> b.apply_load(R3, start=0, order=-1, dir="z")
>>> b.apply_load(R4, start=30, order=-1, dir="z")
>>> b.solve_for_reaction_loads(R1, R2, R3, R4)
>>> b.reaction_loads
{R1: -120, R2: -120, R3: -1350, R4: -2700}
"""
x = self.variable
l = self.length
q = self._load_Singularity
shear_curves = [integrate(load, x) for load in q]
moment_curves = [integrate(shear, x) for shear in shear_curves]
for i in range(3):
react = [r for r in reaction if (shear_curves[i].has(r) or moment_curves[i].has(r))]
if len(react) == 0:
continue
shear_curve = limit(shear_curves[i], x, l)
moment_curve = limit(moment_curves[i], x, l)
sol = list((linsolve([shear_curve, moment_curve], react).args)[0])
sol_dict = dict(zip(react, sol))
reaction_loads = self._reaction_loads
# Check if any of the evaluated reaction exists in another direction
# and if it exists then it should have same value.
for key in sol_dict:
if key in reaction_loads and sol_dict[key] != reaction_loads[key]:
raise ValueError("Ambiguous solution for %s in different directions." % key)
self._reaction_loads.update(sol_dict)
def shear_force(self):
"""
Returns a list of three expressions which represents the shear force
curve of the Beam object along all three axes.
"""
x = self.variable
q = self._load_vector
return [integrate(-q[0], x), integrate(-q[1], x), integrate(-q[2], x)]
def axial_force(self):
"""
Returns expression of Axial shear force present inside the Beam object.
"""
return self.shear_force()[0]
def shear_stress(self):
"""
Returns a list of three expressions which represents the shear stress
curve of the Beam object along all three axes.
"""
return [self.shear_force()[0]/self._area, self.shear_force()[1]/self._area, self.shear_force()[2]/self._area]
def axial_stress(self):
"""
Returns expression of Axial stress present inside the Beam object.
"""
return self.axial_force()/self._area
def bending_moment(self):
"""
Returns a list of three expressions which represents the bending moment
curve of the Beam object along all three axes.
"""
x = self.variable
m = self._moment_load_vector
shear = self.shear_force()
return [integrate(-m[0], x), integrate(-m[1] + shear[2], x),
integrate(-m[2] - shear[1], x) ]
def torsional_moment(self):
"""
Returns expression of Torsional moment present inside the Beam object.
"""
return self.bending_moment()[0]
def solve_for_torsion(self):
"""
Solves for the angular deflection due to the torsional effects of
moments being applied in the x-direction i.e. out of or into the beam.
Here, a positive torque means the direction of the torque is positive
i.e. out of the beam along the beam-axis. Likewise, a negative torque
signifies a torque into the beam cross-section.
Examples
========
>>> from sympy.physics.continuum_mechanics.beam import Beam3D
>>> from sympy import symbols
>>> l, E, G, I, A, x = symbols('l, E, G, I, A, x')
>>> b = Beam3D(20, E, G, I, A, x)
>>> b.apply_moment_load(4, 4, -2, dir='x')
>>> b.apply_moment_load(4, 8, -2, dir='x')
>>> b.apply_moment_load(4, 8, -2, dir='x')
>>> b.solve_for_torsion()
>>> b.angular_deflection().subs(x, 3)
18/(G*I)
"""
x = self.variable
sum_moments = 0
for point in list(self._torsion_moment):
sum_moments += self._torsion_moment[point]
list(self._torsion_moment).sort()
pointsList = list(self._torsion_moment)
torque_diagram = Piecewise((sum_moments, x<=pointsList[0]), (0, x>=pointsList[0]))
for i in range(len(pointsList))[1:]:
sum_moments -= self._torsion_moment[pointsList[i-1]]
torque_diagram += Piecewise((0, x<=pointsList[i-1]), (sum_moments, x<=pointsList[i]), (0, x>=pointsList[i]))
integrated_torque_diagram = integrate(torque_diagram)
self._angular_deflection = integrated_torque_diagram/(self.shear_modulus*self.polar_moment())
def solve_slope_deflection(self):
x = self.variable
l = self.length
E = self.elastic_modulus
G = self.shear_modulus
I = self.second_moment
if isinstance(I, list):
I_y, I_z = I[0], I[1]
else:
I_y = I_z = I
A = self._area
load = self._load_vector
moment = self._moment_load_vector
defl = Function('defl')
theta = Function('theta')
# Finding deflection along x-axis(and corresponding slope value by differentiating it)
# Equation used: Derivative(E*A*Derivative(def_x(x), x), x) + load_x = 0
eq = Derivative(E*A*Derivative(defl(x), x), x) + load[0]
def_x = dsolve(Eq(eq, 0), defl(x)).args[1]
# Solving constants originated from dsolve
C1 = Symbol('C1')
C2 = Symbol('C2')
constants = list((linsolve([def_x.subs(x, 0), def_x.subs(x, l)], C1, C2).args)[0])
def_x = def_x.subs({C1:constants[0], C2:constants[1]})
slope_x = def_x.diff(x)
self._deflection[0] = def_x
self._slope[0] = slope_x
# Finding deflection along y-axis and slope across z-axis. System of equation involved:
# 1: Derivative(E*I_z*Derivative(theta_z(x), x), x) + G*A*(Derivative(defl_y(x), x) - theta_z(x)) + moment_z = 0
# 2: Derivative(G*A*(Derivative(defl_y(x), x) - theta_z(x)), x) + load_y = 0
C_i = Symbol('C_i')
# Substitute value of `G*A*(Derivative(defl_y(x), x) - theta_z(x))` from (2) in (1)
eq1 = Derivative(E*I_z*Derivative(theta(x), x), x) + (integrate(-load[1], x) + C_i) + moment[2]
slope_z = dsolve(Eq(eq1, 0)).args[1]
# Solve for constants originated from using dsolve on eq1
constants = list((linsolve([slope_z.subs(x, 0), slope_z.subs(x, l)], C1, C2).args)[0])
slope_z = slope_z.subs({C1:constants[0], C2:constants[1]})
# Put value of slope obtained back in (2) to solve for `C_i` and find deflection across y-axis
eq2 = G*A*(Derivative(defl(x), x)) + load[1]*x - C_i - G*A*slope_z
def_y = dsolve(Eq(eq2, 0), defl(x)).args[1]
# Solve for constants originated from using dsolve on eq2
constants = list((linsolve([def_y.subs(x, 0), def_y.subs(x, l)], C1, C_i).args)[0])
self._deflection[1] = def_y.subs({C1:constants[0], C_i:constants[1]})
self._slope[2] = slope_z.subs(C_i, constants[1])
# Finding deflection along z-axis and slope across y-axis. System of equation involved:
# 1: Derivative(E*I_y*Derivative(theta_y(x), x), x) - G*A*(Derivative(defl_z(x), x) + theta_y(x)) + moment_y = 0
# 2: Derivative(G*A*(Derivative(defl_z(x), x) + theta_y(x)), x) + load_z = 0
# Substitute value of `G*A*(Derivative(defl_y(x), x) + theta_z(x))` from (2) in (1)
eq1 = Derivative(E*I_y*Derivative(theta(x), x), x) + (integrate(load[2], x) - C_i) + moment[1]
slope_y = dsolve(Eq(eq1, 0)).args[1]
# Solve for constants originated from using dsolve on eq1
constants = list((linsolve([slope_y.subs(x, 0), slope_y.subs(x, l)], C1, C2).args)[0])
slope_y = slope_y.subs({C1:constants[0], C2:constants[1]})
# Put value of slope obtained back in (2) to solve for `C_i` and find deflection across z-axis
eq2 = G*A*(Derivative(defl(x), x)) + load[2]*x - C_i + G*A*slope_y
def_z = dsolve(Eq(eq2,0)).args[1]
# Solve for constants originated from using dsolve on eq2
constants = list((linsolve([def_z.subs(x, 0), def_z.subs(x, l)], C1, C_i).args)[0])
self._deflection[2] = def_z.subs({C1:constants[0], C_i:constants[1]})
self._slope[1] = slope_y.subs(C_i, constants[1])
def slope(self):
"""
Returns a three element list representing slope of deflection curve
along all the three axes.
"""
return self._slope
def deflection(self):
"""
Returns a three element list representing deflection curve along all
the three axes.
"""
return self._deflection
def angular_deflection(self):
"""
Returns a function in x depicting how the angular deflection, due to moments
in the x-axis on the beam, varies with x.
"""
return self._angular_deflection
def _plot_shear_force(self, dir, subs=None):
shear_force = self.shear_force()
if dir == 'x':
dir_num = 0
color = 'r'
elif dir == 'y':
dir_num = 1
color = 'g'
elif dir == 'z':
dir_num = 2
color = 'b'
if subs is None:
subs = {}
for sym in shear_force[dir_num].atoms(Symbol):
if sym != self.variable and sym not in subs:
raise ValueError('Value of %s was not passed.' %sym)
if self.length in subs:
length = subs[self.length]
else:
length = self.length
return plot(shear_force[dir_num].subs(subs), (self.variable, 0, length), show = False, title='Shear Force along %c direction'%dir,
xlabel=r'$\mathrm{X}$', ylabel=r'$\mathrm{V(%c)}$'%dir, line_color=color)
def plot_shear_force(self, dir="all", subs=None):
"""
Returns a plot for Shear force along all three directions
present in the Beam object.
Parameters
==========
dir : string (default : "all")
Direction along which shear force plot is required.
If no direction is specified, all plots are displayed.
subs : dictionary
Python dictionary containing Symbols as key and their
corresponding values.
Examples
========
There is a beam of length 20 meters. It is supported by rollers
at both of its ends. A linear load having slope equal to 12 is applied
along y-axis. A constant distributed load of magnitude 15 N is
applied from start till its end along z-axis.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy.physics.continuum_mechanics.beam import Beam3D
>>> from sympy import symbols
>>> l, E, G, I, A, x = symbols('l, E, G, I, A, x')
>>> b = Beam3D(20, E, G, I, A, x)
>>> b.apply_load(15, start=0, order=0, dir="z")
>>> b.apply_load(12*x, start=0, order=0, dir="y")
>>> b.bc_deflection = [(0, [0, 0, 0]), (20, [0, 0, 0])]
>>> R1, R2, R3, R4 = symbols('R1, R2, R3, R4')
>>> b.apply_load(R1, start=0, order=-1, dir="z")
>>> b.apply_load(R2, start=20, order=-1, dir="z")
>>> b.apply_load(R3, start=0, order=-1, dir="y")
>>> b.apply_load(R4, start=20, order=-1, dir="y")
>>> b.solve_for_reaction_loads(R1, R2, R3, R4)
>>> b.plot_shear_force()
PlotGrid object containing:
Plot[0]:Plot object containing:
[0]: cartesian line: 0 for x over (0.0, 20.0)
Plot[1]:Plot object containing:
[0]: cartesian line: -6*x**2 for x over (0.0, 20.0)
Plot[2]:Plot object containing:
[0]: cartesian line: -15*x for x over (0.0, 20.0)
"""
dir = dir.lower()
# For shear force along x direction
if dir == "x":
Px = self._plot_shear_force('x', subs)
return Px.show()
# For shear force along y direction
elif dir == "y":
Py = self._plot_shear_force('y', subs)
return Py.show()
# For shear force along z direction
elif dir == "z":
Pz = self._plot_shear_force('z', subs)
return Pz.show()
# For shear force along all direction
else:
Px = self._plot_shear_force('x', subs)
Py = self._plot_shear_force('y', subs)
Pz = self._plot_shear_force('z', subs)
return PlotGrid(3, 1, Px, Py, Pz)
def _plot_bending_moment(self, dir, subs=None):
bending_moment = self.bending_moment()
if dir == 'x':
dir_num = 0
color = 'g'
elif dir == 'y':
dir_num = 1
color = 'c'
elif dir == 'z':
dir_num = 2
color = 'm'
if subs is None:
subs = {}
for sym in bending_moment[dir_num].atoms(Symbol):
if sym != self.variable and sym not in subs:
raise ValueError('Value of %s was not passed.' %sym)
if self.length in subs:
length = subs[self.length]
else:
length = self.length
return plot(bending_moment[dir_num].subs(subs), (self.variable, 0, length), show = False, title='Bending Moment along %c direction'%dir,
xlabel=r'$\mathrm{X}$', ylabel=r'$\mathrm{M(%c)}$'%dir, line_color=color)
def plot_bending_moment(self, dir="all", subs=None):
"""
Returns a plot for bending moment along all three directions
present in the Beam object.
Parameters
==========
dir : string (default : "all")
Direction along which bending moment plot is required.
If no direction is specified, all plots are displayed.
subs : dictionary
Python dictionary containing Symbols as key and their
corresponding values.
Examples
========
There is a beam of length 20 meters. It is supported by rollers
at both of its ends. A linear load having slope equal to 12 is applied
along y-axis. A constant distributed load of magnitude 15 N is
applied from start till its end along z-axis.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy.physics.continuum_mechanics.beam import Beam3D
>>> from sympy import symbols
>>> l, E, G, I, A, x = symbols('l, E, G, I, A, x')
>>> b = Beam3D(20, E, G, I, A, x)
>>> b.apply_load(15, start=0, order=0, dir="z")
>>> b.apply_load(12*x, start=0, order=0, dir="y")
>>> b.bc_deflection = [(0, [0, 0, 0]), (20, [0, 0, 0])]
>>> R1, R2, R3, R4 = symbols('R1, R2, R3, R4')
>>> b.apply_load(R1, start=0, order=-1, dir="z")
>>> b.apply_load(R2, start=20, order=-1, dir="z")
>>> b.apply_load(R3, start=0, order=-1, dir="y")
>>> b.apply_load(R4, start=20, order=-1, dir="y")
>>> b.solve_for_reaction_loads(R1, R2, R3, R4)
>>> b.plot_bending_moment()
PlotGrid object containing:
Plot[0]:Plot object containing:
[0]: cartesian line: 0 for x over (0.0, 20.0)
Plot[1]:Plot object containing:
[0]: cartesian line: -15*x**2/2 for x over (0.0, 20.0)
Plot[2]:Plot object containing:
[0]: cartesian line: 2*x**3 for x over (0.0, 20.0)
"""
dir = dir.lower()
# For bending moment along x direction
if dir == "x":
Px = self._plot_bending_moment('x', subs)
return Px.show()
# For bending moment along y direction
elif dir == "y":
Py = self._plot_bending_moment('y', subs)
return Py.show()
# For bending moment along z direction
elif dir == "z":
Pz = self._plot_bending_moment('z', subs)
return Pz.show()
# For bending moment along all direction
else:
Px = self._plot_bending_moment('x', subs)
Py = self._plot_bending_moment('y', subs)
Pz = self._plot_bending_moment('z', subs)
return PlotGrid(3, 1, Px, Py, Pz)
def _plot_slope(self, dir, subs=None):
slope = self.slope()
if dir == 'x':
dir_num = 0
color = 'b'
elif dir == 'y':
dir_num = 1
color = 'm'
elif dir == 'z':
dir_num = 2
color = 'g'
if subs is None:
subs = {}
for sym in slope[dir_num].atoms(Symbol):
if sym != self.variable and sym not in subs:
raise ValueError('Value of %s was not passed.' %sym)
if self.length in subs:
length = subs[self.length]
else:
length = self.length
return plot(slope[dir_num].subs(subs), (self.variable, 0, length), show = False, title='Slope along %c direction'%dir,
xlabel=r'$\mathrm{X}$', ylabel=r'$\mathrm{\theta(%c)}$'%dir, line_color=color)
def plot_slope(self, dir="all", subs=None):
"""
Returns a plot for Slope along all three directions
present in the Beam object.
Parameters
==========
dir : string (default : "all")
Direction along which Slope plot is required.
If no direction is specified, all plots are displayed.
subs : dictionary
Python dictionary containing Symbols as keys and their
corresponding values.
Examples
========
There is a beam of length 20 meters. It is supported by rollers
at both of its ends. A linear load having slope equal to 12 is applied
along y-axis. A constant distributed load of magnitude 15 N is
applied from start till its end along z-axis.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy.physics.continuum_mechanics.beam import Beam3D
>>> from sympy import symbols
>>> l, E, G, I, A, x = symbols('l, E, G, I, A, x')
>>> b = Beam3D(20, 40, 21, 100, 25, x)
>>> b.apply_load(15, start=0, order=0, dir="z")
>>> b.apply_load(12*x, start=0, order=0, dir="y")
>>> b.bc_deflection = [(0, [0, 0, 0]), (20, [0, 0, 0])]
>>> R1, R2, R3, R4 = symbols('R1, R2, R3, R4')
>>> b.apply_load(R1, start=0, order=-1, dir="z")
>>> b.apply_load(R2, start=20, order=-1, dir="z")
>>> b.apply_load(R3, start=0, order=-1, dir="y")
>>> b.apply_load(R4, start=20, order=-1, dir="y")
>>> b.solve_for_reaction_loads(R1, R2, R3, R4)
>>> b.solve_slope_deflection()
>>> b.plot_slope()
PlotGrid object containing:
Plot[0]:Plot object containing:
[0]: cartesian line: 0 for x over (0.0, 20.0)
Plot[1]:Plot object containing:
[0]: cartesian line: -x**3/1600 + 3*x**2/160 - x/8 for x over (0.0, 20.0)
Plot[2]:Plot object containing:
[0]: cartesian line: x**4/8000 - 19*x**2/172 + 52*x/43 for x over (0.0, 20.0)
"""
dir = dir.lower()
# For Slope along x direction
if dir == "x":
Px = self._plot_slope('x', subs)
return Px.show()
# For Slope along y direction
elif dir == "y":
Py = self._plot_slope('y', subs)
return Py.show()
# For Slope along z direction
elif dir == "z":
Pz = self._plot_slope('z', subs)
return Pz.show()
# For Slope along all direction
else:
Px = self._plot_slope('x', subs)
Py = self._plot_slope('y', subs)
Pz = self._plot_slope('z', subs)
return PlotGrid(3, 1, Px, Py, Pz)
def _plot_deflection(self, dir, subs=None):
deflection = self.deflection()
if dir == 'x':
dir_num = 0
color = 'm'
elif dir == 'y':
dir_num = 1
color = 'r'
elif dir == 'z':
dir_num = 2
color = 'c'
if subs is None:
subs = {}
for sym in deflection[dir_num].atoms(Symbol):
if sym != self.variable and sym not in subs:
raise ValueError('Value of %s was not passed.' %sym)
if self.length in subs:
length = subs[self.length]
else:
length = self.length
return plot(deflection[dir_num].subs(subs), (self.variable, 0, length), show = False, title='Deflection along %c direction'%dir,
xlabel=r'$\mathrm{X}$', ylabel=r'$\mathrm{\delta(%c)}$'%dir, line_color=color)
def plot_deflection(self, dir="all", subs=None):
"""
Returns a plot for Deflection along all three directions
present in the Beam object.
Parameters
==========
dir : string (default : "all")
Direction along which deflection plot is required.
If no direction is specified, all plots are displayed.
subs : dictionary
Python dictionary containing Symbols as keys and their
corresponding values.
Examples
========
There is a beam of length 20 meters. It is supported by rollers
at both of its ends. A linear load having slope equal to 12 is applied
along y-axis. A constant distributed load of magnitude 15 N is
applied from start till its end along z-axis.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy.physics.continuum_mechanics.beam import Beam3D
>>> from sympy import symbols
>>> l, E, G, I, A, x = symbols('l, E, G, I, A, x')
>>> b = Beam3D(20, 40, 21, 100, 25, x)
>>> b.apply_load(15, start=0, order=0, dir="z")
>>> b.apply_load(12*x, start=0, order=0, dir="y")
>>> b.bc_deflection = [(0, [0, 0, 0]), (20, [0, 0, 0])]
>>> R1, R2, R3, R4 = symbols('R1, R2, R3, R4')
>>> b.apply_load(R1, start=0, order=-1, dir="z")
>>> b.apply_load(R2, start=20, order=-1, dir="z")
>>> b.apply_load(R3, start=0, order=-1, dir="y")
>>> b.apply_load(R4, start=20, order=-1, dir="y")
>>> b.solve_for_reaction_loads(R1, R2, R3, R4)
>>> b.solve_slope_deflection()
>>> b.plot_deflection()
PlotGrid object containing:
Plot[0]:Plot object containing:
[0]: cartesian line: 0 for x over (0.0, 20.0)
Plot[1]:Plot object containing:
[0]: cartesian line: x**5/40000 - 4013*x**3/90300 + 26*x**2/43 + 1520*x/903 for x over (0.0, 20.0)
Plot[2]:Plot object containing:
[0]: cartesian line: x**4/6400 - x**3/160 + 27*x**2/560 + 2*x/7 for x over (0.0, 20.0)
"""
dir = dir.lower()
# For deflection along x direction
if dir == "x":
Px = self._plot_deflection('x', subs)
return Px.show()
# For deflection along y direction
elif dir == "y":
Py = self._plot_deflection('y', subs)
return Py.show()
# For deflection along z direction
elif dir == "z":
Pz = self._plot_deflection('z', subs)
return Pz.show()
# For deflection along all direction
else:
Px = self._plot_deflection('x', subs)
Py = self._plot_deflection('y', subs)
Pz = self._plot_deflection('z', subs)
return PlotGrid(3, 1, Px, Py, Pz)
def plot_loading_results(self, dir='x', subs=None):
"""
Returns a subplot of Shear Force, Bending Moment,
Slope and Deflection of the Beam object along the direction specified.
Parameters
==========
dir : string (default : "x")
Direction along which plots are required.
If no direction is specified, plots along x-axis are displayed.
subs : dictionary
Python dictionary containing Symbols as key and their
corresponding values.
Examples
========
There is a beam of length 20 meters. It is supported by rollers
at both of its ends. A linear load having slope equal to 12 is applied
along y-axis. A constant distributed load of magnitude 15 N is
applied from start till its end along z-axis.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy.physics.continuum_mechanics.beam import Beam3D
>>> from sympy import symbols
>>> l, E, G, I, A, x = symbols('l, E, G, I, A, x')
>>> b = Beam3D(20, E, G, I, A, x)
>>> subs = {E:40, G:21, I:100, A:25}
>>> b.apply_load(15, start=0, order=0, dir="z")
>>> b.apply_load(12*x, start=0, order=0, dir="y")
>>> b.bc_deflection = [(0, [0, 0, 0]), (20, [0, 0, 0])]
>>> R1, R2, R3, R4 = symbols('R1, R2, R3, R4')
>>> b.apply_load(R1, start=0, order=-1, dir="z")
>>> b.apply_load(R2, start=20, order=-1, dir="z")
>>> b.apply_load(R3, start=0, order=-1, dir="y")
>>> b.apply_load(R4, start=20, order=-1, dir="y")
>>> b.solve_for_reaction_loads(R1, R2, R3, R4)
>>> b.solve_slope_deflection()
>>> b.plot_loading_results('y',subs)
PlotGrid object containing:
Plot[0]:Plot object containing:
[0]: cartesian line: -6*x**2 for x over (0.0, 20.0)
Plot[1]:Plot object containing:
[0]: cartesian line: -15*x**2/2 for x over (0.0, 20.0)
Plot[2]:Plot object containing:
[0]: cartesian line: -x**3/1600 + 3*x**2/160 - x/8 for x over (0.0, 20.0)
Plot[3]:Plot object containing:
[0]: cartesian line: x**5/40000 - 4013*x**3/90300 + 26*x**2/43 + 1520*x/903 for x over (0.0, 20.0)
"""
dir = dir.lower()
if subs is None:
subs = {}
ax1 = self._plot_shear_force(dir, subs)
ax2 = self._plot_bending_moment(dir, subs)
ax3 = self._plot_slope(dir, subs)
ax4 = self._plot_deflection(dir, subs)
return PlotGrid(4, 1, ax1, ax2, ax3, ax4)
def _plot_shear_stress(self, dir, subs=None):
shear_stress = self.shear_stress()
if dir == 'x':
dir_num = 0
color = 'r'
elif dir == 'y':
dir_num = 1
color = 'g'
elif dir == 'z':
dir_num = 2
color = 'b'
if subs is None:
subs = {}
for sym in shear_stress[dir_num].atoms(Symbol):
if sym != self.variable and sym not in subs:
raise ValueError('Value of %s was not passed.' %sym)
if self.length in subs:
length = subs[self.length]
else:
length = self.length
return plot(shear_stress[dir_num].subs(subs), (self.variable, 0, length), show = False, title='Shear stress along %c direction'%dir,
xlabel=r'$\mathrm{X}$', ylabel=r'$\tau(%c)$'%dir, line_color=color)
def plot_shear_stress(self, dir="all", subs=None):
"""
Returns a plot for Shear Stress along all three directions
present in the Beam object.
Parameters
==========
dir : string (default : "all")
Direction along which shear stress plot is required.
If no direction is specified, all plots are displayed.
subs : dictionary
Python dictionary containing Symbols as key and their
corresponding values.
Examples
========
There is a beam of length 20 meters and area of cross section 2 square
meters. It is supported by rollers at both of its ends. A linear load having
slope equal to 12 is applied along y-axis. A constant distributed load
of magnitude 15 N is applied from start till its end along z-axis.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy.physics.continuum_mechanics.beam import Beam3D
>>> from sympy import symbols
>>> l, E, G, I, A, x = symbols('l, E, G, I, A, x')
>>> b = Beam3D(20, E, G, I, 2, x)
>>> b.apply_load(15, start=0, order=0, dir="z")
>>> b.apply_load(12*x, start=0, order=0, dir="y")
>>> b.bc_deflection = [(0, [0, 0, 0]), (20, [0, 0, 0])]
>>> R1, R2, R3, R4 = symbols('R1, R2, R3, R4')
>>> b.apply_load(R1, start=0, order=-1, dir="z")
>>> b.apply_load(R2, start=20, order=-1, dir="z")
>>> b.apply_load(R3, start=0, order=-1, dir="y")
>>> b.apply_load(R4, start=20, order=-1, dir="y")
>>> b.solve_for_reaction_loads(R1, R2, R3, R4)
>>> b.plot_shear_stress()
PlotGrid object containing:
Plot[0]:Plot object containing:
[0]: cartesian line: 0 for x over (0.0, 20.0)
Plot[1]:Plot object containing:
[0]: cartesian line: -3*x**2 for x over (0.0, 20.0)
Plot[2]:Plot object containing:
[0]: cartesian line: -15*x/2 for x over (0.0, 20.0)
"""
dir = dir.lower()
# For shear stress along x direction
if dir == "x":
Px = self._plot_shear_stress('x', subs)
return Px.show()
# For shear stress along y direction
elif dir == "y":
Py = self._plot_shear_stress('y', subs)
return Py.show()
# For shear stress along z direction
elif dir == "z":
Pz = self._plot_shear_stress('z', subs)
return Pz.show()
# For shear stress along all direction
else:
Px = self._plot_shear_stress('x', subs)
Py = self._plot_shear_stress('y', subs)
Pz = self._plot_shear_stress('z', subs)
return PlotGrid(3, 1, Px, Py, Pz)
def _max_shear_force(self, dir):
"""
Helper function for max_shear_force().
"""
dir = dir.lower()
if dir == 'x':
dir_num = 0
elif dir == 'y':
dir_num = 1
elif dir == 'z':
dir_num = 2
if not self.shear_force()[dir_num]:
return (0,0)
# To restrict the range within length of the Beam
load_curve = Piecewise((float("nan"), self.variable<=0),
(self._load_vector[dir_num], self.variable<self.length),
(float("nan"), True))
points = solve(load_curve.rewrite(Piecewise), self.variable,
domain=S.Reals)
points.append(0)
points.append(self.length)
shear_curve = self.shear_force()[dir_num]
shear_values = [shear_curve.subs(self.variable, x) for x in points]
shear_values = list(map(abs, shear_values))
max_shear = max(shear_values)
return (points[shear_values.index(max_shear)], max_shear)
def max_shear_force(self):
"""
Returns point of max shear force and its corresponding shear value
along all directions in a Beam object as a list.
solve_for_reaction_loads() must be called before using this function.
Examples
========
There is a beam of length 20 meters. It is supported by rollers
at both of its ends. A linear load having slope equal to 12 is applied
along y-axis. A constant distributed load of magnitude 15 N is
applied from start till its end along z-axis.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy.physics.continuum_mechanics.beam import Beam3D
>>> from sympy import symbols
>>> l, E, G, I, A, x = symbols('l, E, G, I, A, x')
>>> b = Beam3D(20, 40, 21, 100, 25, x)
>>> b.apply_load(15, start=0, order=0, dir="z")
>>> b.apply_load(12*x, start=0, order=0, dir="y")
>>> b.bc_deflection = [(0, [0, 0, 0]), (20, [0, 0, 0])]
>>> R1, R2, R3, R4 = symbols('R1, R2, R3, R4')
>>> b.apply_load(R1, start=0, order=-1, dir="z")
>>> b.apply_load(R2, start=20, order=-1, dir="z")
>>> b.apply_load(R3, start=0, order=-1, dir="y")
>>> b.apply_load(R4, start=20, order=-1, dir="y")
>>> b.solve_for_reaction_loads(R1, R2, R3, R4)
>>> b.max_shear_force()
[(0, 0), (20, 2400), (20, 300)]
"""
max_shear = []
max_shear.append(self._max_shear_force('x'))
max_shear.append(self._max_shear_force('y'))
max_shear.append(self._max_shear_force('z'))
return max_shear
def _max_bending_moment(self, dir):
"""
Helper function for max_bending_moment().
"""
dir = dir.lower()
if dir == 'x':
dir_num = 0
elif dir == 'y':
dir_num = 1
elif dir == 'z':
dir_num = 2
if not self.bending_moment()[dir_num]:
return (0,0)
# To restrict the range within length of the Beam
shear_curve = Piecewise((float("nan"), self.variable<=0),
(self.shear_force()[dir_num], self.variable<self.length),
(float("nan"), True))
points = solve(shear_curve.rewrite(Piecewise), self.variable,
domain=S.Reals)
points.append(0)
points.append(self.length)
bending_moment_curve = self.bending_moment()[dir_num]
bending_moments = [bending_moment_curve.subs(self.variable, x) for x in points]
bending_moments = list(map(abs, bending_moments))
max_bending_moment = max(bending_moments)
return (points[bending_moments.index(max_bending_moment)], max_bending_moment)
def max_bending_moment(self):
"""
Returns point of max bending moment and its corresponding bending moment value
along all directions in a Beam object as a list.
solve_for_reaction_loads() must be called before using this function.
Examples
========
There is a beam of length 20 meters. It is supported by rollers
at both of its ends. A linear load having slope equal to 12 is applied
along y-axis. A constant distributed load of magnitude 15 N is
applied from start till its end along z-axis.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy.physics.continuum_mechanics.beam import Beam3D
>>> from sympy import symbols
>>> l, E, G, I, A, x = symbols('l, E, G, I, A, x')
>>> b = Beam3D(20, 40, 21, 100, 25, x)
>>> b.apply_load(15, start=0, order=0, dir="z")
>>> b.apply_load(12*x, start=0, order=0, dir="y")
>>> b.bc_deflection = [(0, [0, 0, 0]), (20, [0, 0, 0])]
>>> R1, R2, R3, R4 = symbols('R1, R2, R3, R4')
>>> b.apply_load(R1, start=0, order=-1, dir="z")
>>> b.apply_load(R2, start=20, order=-1, dir="z")
>>> b.apply_load(R3, start=0, order=-1, dir="y")
>>> b.apply_load(R4, start=20, order=-1, dir="y")
>>> b.solve_for_reaction_loads(R1, R2, R3, R4)
>>> b.max_bending_moment()
[(0, 0), (20, 3000), (20, 16000)]
"""
max_bmoment = []
max_bmoment.append(self._max_bending_moment('x'))
max_bmoment.append(self._max_bending_moment('y'))
max_bmoment.append(self._max_bending_moment('z'))
return max_bmoment
max_bmoment = max_bending_moment
def _max_deflection(self, dir):
"""
Helper function for max_Deflection()
"""
dir = dir.lower()
if dir == 'x':
dir_num = 0
elif dir == 'y':
dir_num = 1
elif dir == 'z':
dir_num = 2
if not self.deflection()[dir_num]:
return (0,0)
# To restrict the range within length of the Beam
slope_curve = Piecewise((float("nan"), self.variable<=0),
(self.slope()[dir_num], self.variable<self.length),
(float("nan"), True))
points = solve(slope_curve.rewrite(Piecewise), self.variable,
domain=S.Reals)
points.append(0)
points.append(self._length)
deflection_curve = self.deflection()[dir_num]
deflections = [deflection_curve.subs(self.variable, x) for x in points]
deflections = list(map(abs, deflections))
max_def = max(deflections)
return (points[deflections.index(max_def)], max_def)
def max_deflection(self):
"""
Returns point of max deflection and its corresponding deflection value
along all directions in a Beam object as a list.
solve_for_reaction_loads() and solve_slope_deflection() must be called
before using this function.
Examples
========
There is a beam of length 20 meters. It is supported by rollers
at both of its ends. A linear load having slope equal to 12 is applied
along y-axis. A constant distributed load of magnitude 15 N is
applied from start till its end along z-axis.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy.physics.continuum_mechanics.beam import Beam3D
>>> from sympy import symbols
>>> l, E, G, I, A, x = symbols('l, E, G, I, A, x')
>>> b = Beam3D(20, 40, 21, 100, 25, x)
>>> b.apply_load(15, start=0, order=0, dir="z")
>>> b.apply_load(12*x, start=0, order=0, dir="y")
>>> b.bc_deflection = [(0, [0, 0, 0]), (20, [0, 0, 0])]
>>> R1, R2, R3, R4 = symbols('R1, R2, R3, R4')
>>> b.apply_load(R1, start=0, order=-1, dir="z")
>>> b.apply_load(R2, start=20, order=-1, dir="z")
>>> b.apply_load(R3, start=0, order=-1, dir="y")
>>> b.apply_load(R4, start=20, order=-1, dir="y")
>>> b.solve_for_reaction_loads(R1, R2, R3, R4)
>>> b.solve_slope_deflection()
>>> b.max_deflection()
[(0, 0), (10, 495/14), (-10 + 10*sqrt(10793)/43, (10 - 10*sqrt(10793)/43)**3/160 - 20/7 + (10 - 10*sqrt(10793)/43)**4/6400 + 20*sqrt(10793)/301 + 27*(10 - 10*sqrt(10793)/43)**2/560)]
"""
max_def = []
max_def.append(self._max_deflection('x'))
max_def.append(self._max_deflection('y'))
max_def.append(self._max_deflection('z'))
return max_def
PK ]ZZZ}ԭ
U
U * sympy/physics/continuum_mechanics/cable.py"""
This module can be used to solve problems related
to 2D Cables.
"""
from sympy.core.sympify import sympify
from sympy.core.symbol import Symbol
from sympy import sin, cos, pi, atan, diff
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.solvers.solveset import linsolve
from sympy.matrices import Matrix
class Cable:
"""
Cables are structures in engineering that support
the applied transverse loads through the tensile
resistance developed in its members.
Cables are widely used in suspension bridges, tension
leg offshore platforms, transmission lines, and find
use in several other engineering applications.
Examples
========
A cable is supported at (0, 10) and (10, 10). Two point loads
acting vertically downwards act on the cable, one with magnitude 3 kN
and acting 2 meters from the left support and 3 meters below it, while
the other with magnitude 2 kN is 6 meters from the left support and
6 meters below it.
>>> from sympy.physics.continuum_mechanics.cable import Cable
>>> c = Cable(('A', 0, 10), ('B', 10, 10))
>>> c.apply_load(-1, ('P', 2, 7, 3, 270))
>>> c.apply_load(-1, ('Q', 6, 4, 2, 270))
>>> c.loads
{'distributed': {}, 'point_load': {'P': [3, 270], 'Q': [2, 270]}}
>>> c.loads_position
{'P': [2, 7], 'Q': [6, 4]}
"""
def __init__(self, support_1, support_2):
"""
Initializes the class.
Parameters
==========
support_1 and support_2 are tuples of the form
(label, x, y), where
label : String or symbol
The label of the support
x : Sympifyable
The x coordinate of the position of the support
y : Sympifyable
The y coordinate of the position of the support
"""
self._left_support = []
self._right_support = []
self._supports = {}
self._support_labels = []
self._loads = {"distributed": {}, "point_load": {}}
self._loads_position = {}
self._length = 0
self._reaction_loads = {}
self._tension = {}
self._lowest_x_global = sympify(0)
if support_1[0] == support_2[0]:
raise ValueError("Supports can not have the same label")
elif support_1[1] == support_2[1]:
raise ValueError("Supports can not be at the same location")
x1 = sympify(support_1[1])
y1 = sympify(support_1[2])
self._supports[support_1[0]] = [x1, y1]
x2 = sympify(support_2[1])
y2 = sympify(support_2[2])
self._supports[support_2[0]] = [x2, y2]
if support_1[1] < support_2[1]:
self._left_support.append(x1)
self._left_support.append(y1)
self._right_support.append(x2)
self._right_support.append(y2)
self._support_labels.append(support_1[0])
self._support_labels.append(support_2[0])
else:
self._left_support.append(x2)
self._left_support.append(y2)
self._right_support.append(x1)
self._right_support.append(y1)
self._support_labels.append(support_2[0])
self._support_labels.append(support_1[0])
for i in self._support_labels:
self._reaction_loads[Symbol("R_"+ i +"_x")] = 0
self._reaction_loads[Symbol("R_"+ i +"_y")] = 0
@property
def supports(self):
"""
Returns the supports of the cable along with their
positions.
"""
return self._supports
@property
def left_support(self):
"""
Returns the position of the left support.
"""
return self._left_support
@property
def right_support(self):
"""
Returns the position of the right support.
"""
return self._right_support
@property
def loads(self):
"""
Returns the magnitude and direction of the loads
acting on the cable.
"""
return self._loads
@property
def loads_position(self):
"""
Returns the position of the point loads acting on the
cable.
"""
return self._loads_position
@property
def length(self):
"""
Returns the length of the cable.
"""
return self._length
@property
def reaction_loads(self):
"""
Returns the reaction forces at the supports, which are
initialized to 0.
"""
return self._reaction_loads
@property
def tension(self):
"""
Returns the tension developed in the cable due to the loads
applied.
"""
return self._tension
def tension_at(self, x):
"""
Returns the tension at a given value of x developed due to
distributed load.
"""
if 'distributed' not in self._tension.keys():
raise ValueError("No distributed load added or solve method not called")
if x > self._right_support[0] or x < self._left_support[0]:
raise ValueError("The value of x should be between the two supports")
A = self._tension['distributed']
X = Symbol('X')
return A.subs({X:(x-self._lowest_x_global)})
def apply_length(self, length):
"""
This method specifies the length of the cable
Parameters
==========
length : Sympifyable
The length of the cable
Examples
========
>>> from sympy.physics.continuum_mechanics.cable import Cable
>>> c = Cable(('A', 0, 10), ('B', 10, 10))
>>> c.apply_length(20)
>>> c.length
20
"""
dist = ((self._left_support[0] - self._right_support[0])**2
- (self._left_support[1] - self._right_support[1])**2)**(1/2)
if length < dist:
raise ValueError("length should not be less than the distance between the supports")
self._length = length
def change_support(self, label, new_support):
"""
This method changes the mentioned support with a new support.
Parameters
==========
label: String or symbol
The label of the support to be changed
new_support: Tuple of the form (new_label, x, y)
new_label: String or symbol
The label of the new support
x: Sympifyable
The x-coordinate of the position of the new support.
y: Sympifyable
The y-coordinate of the position of the new support.
Examples
========
>>> from sympy.physics.continuum_mechanics.cable import Cable
>>> c = Cable(('A', 0, 10), ('B', 10, 10))
>>> c.supports
{'A': [0, 10], 'B': [10, 10]}
>>> c.change_support('B', ('C', 5, 6))
>>> c.supports
{'A': [0, 10], 'C': [5, 6]}
"""
if label not in self._supports:
raise ValueError("No support exists with the given label")
i = self._support_labels.index(label)
rem_label = self._support_labels[(i+1)%2]
x1 = self._supports[rem_label][0]
y1 = self._supports[rem_label][1]
x = sympify(new_support[1])
y = sympify(new_support[2])
for l in self._loads_position:
if l[0] >= max(x, x1) or l[0] <= min(x, x1):
raise ValueError("The change in support will throw an existing load out of range")
self._supports.pop(label)
self._left_support.clear()
self._right_support.clear()
self._reaction_loads.clear()
self._support_labels.remove(label)
self._supports[new_support[0]] = [x, y]
if x1 < x:
self._left_support.append(x1)
self._left_support.append(y1)
self._right_support.append(x)
self._right_support.append(y)
self._support_labels.append(new_support[0])
else:
self._left_support.append(x)
self._left_support.append(y)
self._right_support.append(x1)
self._right_support.append(y1)
self._support_labels.insert(0, new_support[0])
for i in self._support_labels:
self._reaction_loads[Symbol("R_"+ i +"_x")] = 0
self._reaction_loads[Symbol("R_"+ i +"_y")] = 0
def apply_load(self, order, load):
"""
This method adds load to the cable.
Parameters
==========
order : Integer
The order of the applied load.
- For point loads, order = -1
- For distributed load, order = 0
load : tuple
* For point loads, load is of the form (label, x, y, magnitude, direction), where:
label : String or symbol
The label of the load
x : Sympifyable
The x coordinate of the position of the load
y : Sympifyable
The y coordinate of the position of the load
magnitude : Sympifyable
The magnitude of the load. It must always be positive
direction : Sympifyable
The angle, in degrees, that the load vector makes with the horizontal
in the counter-clockwise direction. It takes the values 0 to 360,
inclusive.
* For uniformly distributed load, load is of the form (label, magnitude)
label : String or symbol
The label of the load
magnitude : Sympifyable
The magnitude of the load. It must always be positive
Examples
========
For a point load of magnitude 12 units inclined at 30 degrees with the horizontal:
>>> from sympy.physics.continuum_mechanics.cable import Cable
>>> c = Cable(('A', 0, 10), ('B', 10, 10))
>>> c.apply_load(-1, ('Z', 5, 5, 12, 30))
>>> c.loads
{'distributed': {}, 'point_load': {'Z': [12, 30]}}
>>> c.loads_position
{'Z': [5, 5]}
For a uniformly distributed load of magnitude 9 units:
>>> from sympy.physics.continuum_mechanics.cable import Cable
>>> c = Cable(('A', 0, 10), ('B', 10, 10))
>>> c.apply_load(0, ('X', 9))
>>> c.loads
{'distributed': {'X': 9}, 'point_load': {}}
"""
if order == -1:
if len(self._loads["distributed"]) != 0:
raise ValueError("Distributed load already exists")
label = load[0]
if label in self._loads["point_load"]:
raise ValueError("Label already exists")
x = sympify(load[1])
y = sympify(load[2])
if x > self._right_support[0] or x < self._left_support[0]:
raise ValueError("The load should be positioned between the supports")
magnitude = sympify(load[3])
direction = sympify(load[4])
self._loads["point_load"][label] = [magnitude, direction]
self._loads_position[label] = [x, y]
elif order == 0:
if len(self._loads_position) != 0:
raise ValueError("Point load(s) already exist")
label = load[0]
if label in self._loads["distributed"]:
raise ValueError("Label already exists")
magnitude = sympify(load[1])
self._loads["distributed"][label] = magnitude
else:
raise ValueError("Order should be either -1 or 0")
def remove_loads(self, *args):
"""
This methods removes the specified loads.
Parameters
==========
This input takes multiple label(s) as input
label(s): String or symbol
The label(s) of the loads to be removed.
Examples
========
>>> from sympy.physics.continuum_mechanics.cable import Cable
>>> c = Cable(('A', 0, 10), ('B', 10, 10))
>>> c.apply_load(-1, ('Z', 5, 5, 12, 30))
>>> c.loads
{'distributed': {}, 'point_load': {'Z': [12, 30]}}
>>> c.remove_loads('Z')
>>> c.loads
{'distributed': {}, 'point_load': {}}
"""
for i in args:
if len(self._loads_position) == 0:
if i not in self._loads['distributed']:
raise ValueError("Error removing load " + i + ": no such load exists")
else:
self._loads['disrtibuted'].pop(i)
else:
if i not in self._loads['point_load']:
raise ValueError("Error removing load " + i + ": no such load exists")
else:
self._loads['point_load'].pop(i)
self._loads_position.pop(i)
def solve(self, *args):
"""
This method solves for the reaction forces at the supports, the tension developed in
the cable, and updates the length of the cable.
Parameters
==========
This method requires no input when solving for point loads
For distributed load, the x and y coordinates of the lowest point of the cable are
required as
x: Sympifyable
The x coordinate of the lowest point
y: Sympifyable
The y coordinate of the lowest point
Examples
========
For point loads,
>>> from sympy.physics.continuum_mechanics.cable import Cable
>>> c = Cable(("A", 0, 10), ("B", 10, 10))
>>> c.apply_load(-1, ('Z', 2, 7.26, 3, 270))
>>> c.apply_load(-1, ('X', 4, 6, 8, 270))
>>> c.solve()
>>> c.tension
{A_Z: 8.91403453669861, X_B: 19*sqrt(13)/10, Z_X: 4.79150773600774}
>>> c.reaction_loads
{R_A_x: -5.25547445255474, R_A_y: 7.2, R_B_x: 5.25547445255474, R_B_y: 3.8}
>>> c.length
5.7560958484519 + 2*sqrt(13)
For distributed load,
>>> from sympy.physics.continuum_mechanics.cable import Cable
>>> c=Cable(("A", 0, 40),("B", 100, 20))
>>> c.apply_load(0, ("X", 850))
>>> c.solve(58.58, 0)
>>> c.tension
{'distributed': 36456.8485*sqrt(0.000543529004799705*(X + 0.00135624381275735)**2 + 1)}
>>> c.tension_at(0)
61709.0363315913
>>> c.reaction_loads
{R_A_x: 36456.8485, R_A_y: -49788.5866682485, R_B_x: 44389.8401587246, R_B_y: 42866.621696333}
"""
if len(self._loads_position) != 0:
sorted_position = sorted(self._loads_position.items(), key = lambda item : item[1][0])
sorted_position.append(self._support_labels[1])
sorted_position.insert(0, self._support_labels[0])
self._tension.clear()
moment_sum_from_left_support = 0
moment_sum_from_right_support = 0
F_x = 0
F_y = 0
self._length = 0
for i in range(1, len(sorted_position)-1):
if i == 1:
self._length+=sqrt((self._left_support[0] - self._loads_position[sorted_position[i][0]][0])**2 + (self._left_support[1] - self._loads_position[sorted_position[i][0]][1])**2)
else:
self._length+=sqrt((self._loads_position[sorted_position[i-1][0]][0] - self._loads_position[sorted_position[i][0]][0])**2 + (self._loads_position[sorted_position[i-1][0]][1] - self._loads_position[sorted_position[i][0]][1])**2)
if i == len(sorted_position)-2:
self._length+=sqrt((self._right_support[0] - self._loads_position[sorted_position[i][0]][0])**2 + (self._right_support[1] - self._loads_position[sorted_position[i][0]][1])**2)
moment_sum_from_left_support += self._loads['point_load'][sorted_position[i][0]][0] * cos(pi * self._loads['point_load'][sorted_position[i][0]][1] / 180) * abs(self._left_support[1] - self._loads_position[sorted_position[i][0]][1])
moment_sum_from_left_support += self._loads['point_load'][sorted_position[i][0]][0] * sin(pi * self._loads['point_load'][sorted_position[i][0]][1] / 180) * abs(self._left_support[0] - self._loads_position[sorted_position[i][0]][0])
F_x += self._loads['point_load'][sorted_position[i][0]][0] * cos(pi * self._loads['point_load'][sorted_position[i][0]][1] / 180)
F_y += self._loads['point_load'][sorted_position[i][0]][0] * sin(pi * self._loads['point_load'][sorted_position[i][0]][1] / 180)
label = Symbol(sorted_position[i][0]+"_"+sorted_position[i+1][0])
y2 = self._loads_position[sorted_position[i][0]][1]
x2 = self._loads_position[sorted_position[i][0]][0]
y1 = 0
x1 = 0
if i == len(sorted_position)-2:
x1 = self._right_support[0]
y1 = self._right_support[1]
else:
x1 = self._loads_position[sorted_position[i+1][0]][0]
y1 = self._loads_position[sorted_position[i+1][0]][1]
angle_with_horizontal = atan((y1 - y2)/(x1 - x2))
tension = -(moment_sum_from_left_support)/(abs(self._left_support[1] - self._loads_position[sorted_position[i][0]][1])*cos(angle_with_horizontal) + abs(self._left_support[0] - self._loads_position[sorted_position[i][0]][0])*sin(angle_with_horizontal))
self._tension[label] = tension
moment_sum_from_right_support += self._loads['point_load'][sorted_position[i][0]][0] * cos(pi * self._loads['point_load'][sorted_position[i][0]][1] / 180) * abs(self._right_support[1] - self._loads_position[sorted_position[i][0]][1])
moment_sum_from_right_support += self._loads['point_load'][sorted_position[i][0]][0] * sin(pi * self._loads['point_load'][sorted_position[i][0]][1] / 180) * abs(self._right_support[0] - self._loads_position[sorted_position[i][0]][0])
label = Symbol(sorted_position[0][0]+"_"+sorted_position[1][0])
y2 = self._loads_position[sorted_position[1][0]][1]
x2 = self._loads_position[sorted_position[1][0]][0]
x1 = self._left_support[0]
y1 = self._left_support[1]
angle_with_horizontal = -atan((y2 - y1)/(x2 - x1))
tension = -(moment_sum_from_right_support)/(abs(self._right_support[1] - self._loads_position[sorted_position[1][0]][1])*cos(angle_with_horizontal) + abs(self._right_support[0] - self._loads_position[sorted_position[1][0]][0])*sin(angle_with_horizontal))
self._tension[label] = tension
angle_with_horizontal = pi/2 - angle_with_horizontal
label = self._support_labels[0]
self._reaction_loads[Symbol("R_"+label+"_x")] = -sin(angle_with_horizontal) * tension
F_x += -sin(angle_with_horizontal) * tension
self._reaction_loads[Symbol("R_"+label+"_y")] = cos(angle_with_horizontal) * tension
F_y += cos(angle_with_horizontal) * tension
label = self._support_labels[1]
self._reaction_loads[Symbol("R_"+label+"_x")] = -F_x
self._reaction_loads[Symbol("R_"+label+"_y")] = -F_y
elif len(self._loads['distributed']) != 0 :
if len(args) == 0:
raise ValueError("Provide the lowest point of the cable")
lowest_x = sympify(args[0])
lowest_y = sympify(args[1])
self._lowest_x_global = lowest_x
a = Symbol('a')
b = Symbol('b')
c = Symbol('c')
# augmented matrix form of linsolve
M = Matrix(
[[self._left_support[0]**2, self._left_support[0], 1, self._left_support[1]],
[self._right_support[0]**2, self._right_support[0], 1, self._right_support[1]],
[lowest_x**2, lowest_x, 1, lowest_y] ]
)
coefficient_solution = list(linsolve(M, (a, b, c)))
if len(coefficient_solution) == 0:
raise ValueError("The lowest point is inconsistent with the supports")
A = coefficient_solution[0][0]
B = coefficient_solution[0][1]
C = coefficient_solution[0][2]
# y = A*x**2 + B*x + C
# shifting origin to lowest point
X = Symbol('X')
Y = Symbol('Y')
Y = A*(X + lowest_x)**2 + B*(X + lowest_x) + C - lowest_y
temp_list = list(self._loads['distributed'].values())
applied_force = temp_list[0]
horizontal_force_constant = (applied_force * (self._right_support[0] - lowest_x)**2) / (2 * (self._right_support[1] - lowest_y))
self._tension.clear()
tangent_slope_to_curve = diff(Y, X)
self._tension['distributed'] = horizontal_force_constant / (cos(atan(tangent_slope_to_curve)))
label = self._support_labels[0]
self._reaction_loads[Symbol("R_"+label+"_x")] = self.tension_at(self._left_support[0]) * cos(atan(tangent_slope_to_curve.subs(X, self._left_support[0] - lowest_x)))
self._reaction_loads[Symbol("R_"+label+"_y")] = self.tension_at(self._left_support[0]) * sin(atan(tangent_slope_to_curve.subs(X, self._left_support[0] - lowest_x)))
label = self._support_labels[1]
self._reaction_loads[Symbol("R_"+label+"_x")] = self.tension_at(self._left_support[0]) * cos(atan(tangent_slope_to_curve.subs(X, self._right_support[0] - lowest_x)))
self._reaction_loads[Symbol("R_"+label+"_y")] = self.tension_at(self._left_support[0]) * sin(atan(tangent_slope_to_curve.subs(X, self._right_support[0] - lowest_x)))
PK ]ZZZ�t��� �� * sympy/physics/continuum_mechanics/truss.py"""
This module can be used to solve problems related
to 2D Trusses.
"""
from cmath import atan, inf
from sympy.core.add import Add
from sympy.core.evalf import INF
from sympy.core.mul import Mul
from sympy.core.symbol import Symbol
from sympy.core.sympify import sympify
from sympy import Matrix, pi
from sympy.external.importtools import import_module
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.matrices.dense import zeros
import math
from sympy.physics.units.quantities import Quantity
from sympy.plotting import plot
from sympy.utilities.decorator import doctest_depends_on
from sympy import sin, cos
__doctest_requires__ = {('Truss.draw'): ['matplotlib']}
numpy = import_module('numpy', import_kwargs={'fromlist':['arange']})
class Truss:
"""
A Truss is an assembly of members such as beams,
connected by nodes, that create a rigid structure.
In engineering, a truss is a structure that
consists of two-force members only.
Trusses are extremely important in engineering applications
and can be seen in numerous real-world applications like bridges.
Examples
========
There is a Truss consisting of four nodes and five
members connecting the nodes. A force P acts
downward on the node D and there also exist pinned
and roller joints on the nodes A and B respectively.
.. image:: truss_example.png
>>> from sympy.physics.continuum_mechanics.truss import Truss
>>> t = Truss()
>>> t.add_node(("node_1", 0, 0), ("node_2", 6, 0), ("node_3", 2, 2), ("node_4", 2, 0))
>>> t.add_member(("member_1", "node_1", "node_4"), ("member_2", "node_2", "node_4"), ("member_3", "node_1", "node_3"))
>>> t.add_member(("member_4", "node_2", "node_3"), ("member_5", "node_3", "node_4"))
>>> t.apply_load(("node_4", 10, 270))
>>> t.apply_support(("node_1", "pinned"), ("node_2", "roller"))
"""
def __init__(self):
"""
Initializes the class
"""
self._nodes = []
self._members = {}
self._loads = {}
self._supports = {}
self._node_labels = []
self._node_positions = []
self._node_position_x = []
self._node_position_y = []
self._nodes_occupied = {}
self._member_lengths = {}
self._reaction_loads = {}
self._internal_forces = {}
self._node_coordinates = {}
@property
def nodes(self):
"""
Returns the nodes of the truss along with their positions.
"""
return self._nodes
@property
def node_labels(self):
"""
Returns the node labels of the truss.
"""
return self._node_labels
@property
def node_positions(self):
"""
Returns the positions of the nodes of the truss.
"""
return self._node_positions
@property
def members(self):
"""
Returns the members of the truss along with the start and end points.
"""
return self._members
@property
def member_lengths(self):
"""
Returns the length of each member of the truss.
"""
return self._member_lengths
@property
def supports(self):
"""
Returns the nodes with provided supports along with the kind of support provided i.e.
pinned or roller.
"""
return self._supports
@property
def loads(self):
"""
Returns the loads acting on the truss.
"""
return self._loads
@property
def reaction_loads(self):
"""
Returns the reaction forces for all supports which are all initialized to 0.
"""
return self._reaction_loads
@property
def internal_forces(self):
"""
Returns the internal forces for all members which are all initialized to 0.
"""
return self._internal_forces
def add_node(self, *args):
"""
This method adds a node to the truss along with its name/label and its location.
Multiple nodes can be added at the same time.
Parameters
==========
The input(s) for this method are tuples of the form (label, x, y).
label: String or a Symbol
The label for a node. It is the only way to identify a particular node.
x: Sympifyable
The x-coordinate of the position of the node.
y: Sympifyable
The y-coordinate of the position of the node.
Examples
========
>>> from sympy.physics.continuum_mechanics.truss import Truss
>>> t = Truss()
>>> t.add_node(('A', 0, 0))
>>> t.nodes
[('A', 0, 0)]
>>> t.add_node(('B', 3, 0), ('C', 4, 1))
>>> t.nodes
[('A', 0, 0), ('B', 3, 0), ('C', 4, 1)]
"""
for i in args:
label = i[0]
x = i[1]
x = sympify(x)
y=i[2]
y = sympify(y)
if label in self._node_coordinates:
raise ValueError("Node needs to have a unique label")
elif [x, y] in self._node_coordinates.values():
raise ValueError("A node already exists at the given position")
else :
self._nodes.append((label, x, y))
self._node_labels.append(label)
self._node_positions.append((x, y))
self._node_position_x.append(x)
self._node_position_y.append(y)
self._node_coordinates[label] = [x, y]
def remove_node(self, *args):
"""
This method removes a node from the truss.
Multiple nodes can be removed at the same time.
Parameters
==========
The input(s) for this method are the labels of the nodes to be removed.
label: String or Symbol
The label of the node to be removed.
Examples
========
>>> from sympy.physics.continuum_mechanics.truss import Truss
>>> t = Truss()
>>> t.add_node(('A', 0, 0), ('B', 3, 0), ('C', 5, 0))
>>> t.nodes
[('A', 0, 0), ('B', 3, 0), ('C', 5, 0)]
>>> t.remove_node('A', 'C')
>>> t.nodes
[('B', 3, 0)]
"""
for label in args:
for i in range(len(self.nodes)):
if self._node_labels[i] == label:
x = self._node_position_x[i]
y = self._node_position_y[i]
if label not in self._node_coordinates:
raise ValueError("No such node exists in the truss")
else:
members_duplicate = self._members.copy()
for member in members_duplicate:
if label == self._members[member][0] or label == self._members[member][1]:
raise ValueError("The given node already has member attached to it")
self._nodes.remove((label, x, y))
self._node_labels.remove(label)
self._node_positions.remove((x, y))
self._node_position_x.remove(x)
self._node_position_y.remove(y)
if label in self._loads:
self._loads.pop(label)
if label in self._supports:
self._supports.pop(label)
self._node_coordinates.pop(label)
def add_member(self, *args):
"""
This method adds a member between any two nodes in the given truss.
Parameters
==========
The input(s) of the method are tuple(s) of the form (label, start, end).
label: String or Symbol
The label for a member. It is the only way to identify a particular member.
start: String or Symbol
The label of the starting point/node of the member.
end: String or Symbol
The label of the ending point/node of the member.
Examples
========
>>> from sympy.physics.continuum_mechanics.truss import Truss
>>> t = Truss()
>>> t.add_node(('A', 0, 0), ('B', 3, 0), ('C', 2, 2))
>>> t.add_member(('AB', 'A', 'B'), ('BC', 'B', 'C'))
>>> t.members
{'AB': ['A', 'B'], 'BC': ['B', 'C']}
"""
for i in args:
label = i[0]
start = i[1]
end = i[2]
if start not in self._node_coordinates or end not in self._node_coordinates or start==end:
raise ValueError("The start and end points of the member must be unique nodes")
elif label in self._members:
raise ValueError("A member with the same label already exists for the truss")
elif self._nodes_occupied.get((start, end)):
raise ValueError("A member already exists between the two nodes")
else:
self._members[label] = [start, end]
self._member_lengths[label] = sqrt((self._node_coordinates[end][0]-self._node_coordinates[start][0])**2 + (self._node_coordinates[end][1]-self._node_coordinates[start][1])**2)
self._nodes_occupied[start, end] = True
self._nodes_occupied[end, start] = True
self._internal_forces[label] = 0
def remove_member(self, *args):
"""
This method removes members from the given truss.
Parameters
==========
labels: String or Symbol
The label for the member to be removed.
Examples
========
>>> from sympy.physics.continuum_mechanics.truss import Truss
>>> t = Truss()
>>> t.add_node(('A', 0, 0), ('B', 3, 0), ('C', 2, 2))
>>> t.add_member(('AB', 'A', 'B'), ('AC', 'A', 'C'), ('BC', 'B', 'C'))
>>> t.members
{'AB': ['A', 'B'], 'AC': ['A', 'C'], 'BC': ['B', 'C']}
>>> t.remove_member('AC', 'BC')
>>> t.members
{'AB': ['A', 'B']}
"""
for label in args:
if label not in self._members:
raise ValueError("No such member exists in the Truss")
else:
self._nodes_occupied.pop((self._members[label][0], self._members[label][1]))
self._nodes_occupied.pop((self._members[label][1], self._members[label][0]))
self._members.pop(label)
self._member_lengths.pop(label)
self._internal_forces.pop(label)
def change_node_label(self, *args):
"""
This method changes the label(s) of the specified node(s).
Parameters
==========
The input(s) of this method are tuple(s) of the form (label, new_label).
label: String or Symbol
The label of the node for which the label has
to be changed.
new_label: String or Symbol
The new label of the node.
Examples
========
>>> from sympy.physics.continuum_mechanics.truss import Truss
>>> t = Truss()
>>> t.add_node(('A', 0, 0), ('B', 3, 0))
>>> t.nodes
[('A', 0, 0), ('B', 3, 0)]
>>> t.change_node_label(('A', 'C'), ('B', 'D'))
>>> t.nodes
[('C', 0, 0), ('D', 3, 0)]
"""
for i in args:
label = i[0]
new_label = i[1]
if label not in self._node_coordinates:
raise ValueError("No such node exists for the Truss")
elif new_label in self._node_coordinates:
raise ValueError("A node with the given label already exists")
else:
for node in self._nodes:
if node[0] == label:
self._nodes[self._nodes.index((label, node[1], node[2]))] = (new_label, node[1], node[2])
self._node_labels[self._node_labels.index(node[0])] = new_label
self._node_coordinates[new_label] = self._node_coordinates[label]
self._node_coordinates.pop(label)
if node[0] in self._supports:
self._supports[new_label] = self._supports[node[0]]
self._supports.pop(node[0])
if new_label in self._supports:
if self._supports[new_label] == 'pinned':
if 'R_'+str(label)+'_x' in self._reaction_loads and 'R_'+str(label)+'_y' in self._reaction_loads:
self._reaction_loads['R_'+str(new_label)+'_x'] = self._reaction_loads['R_'+str(label)+'_x']
self._reaction_loads['R_'+str(new_label)+'_y'] = self._reaction_loads['R_'+str(label)+'_y']
self._reaction_loads.pop('R_'+str(label)+'_x')
self._reaction_loads.pop('R_'+str(label)+'_y')
self._loads[new_label] = self._loads[label]
for load in self._loads[new_label]:
if load[1] == 90:
load[0] -= Symbol('R_'+str(label)+'_y')
if load[0] == 0:
self._loads[label].remove(load)
break
for load in self._loads[new_label]:
if load[1] == 0:
load[0] -= Symbol('R_'+str(label)+'_x')
if load[0] == 0:
self._loads[label].remove(load)
break
self.apply_load(new_label, Symbol('R_'+str(new_label)+'_x'), 0)
self.apply_load(new_label, Symbol('R_'+str(new_label)+'_y'), 90)
self._loads.pop(label)
elif self._supports[new_label] == 'roller':
self._loads[new_label] = self._loads[label]
for load in self._loads[label]:
if load[1] == 90:
load[0] -= Symbol('R_'+str(label)+'_y')
if load[0] == 0:
self._loads[label].remove(load)
break
self.apply_load(new_label, Symbol('R_'+str(new_label)+'_y'), 90)
self._loads.pop(label)
else:
if label in self._loads:
self._loads[new_label] = self._loads[label]
self._loads.pop(label)
for member in self._members:
if self._members[member][0] == node[0]:
self._members[member][0] = new_label
self._nodes_occupied[(new_label, self._members[member][1])] = True
self._nodes_occupied[(self._members[member][1], new_label)] = True
self._nodes_occupied.pop((label, self._members[member][1]))
self._nodes_occupied.pop((self._members[member][1], label))
elif self._members[member][1] == node[0]:
self._members[member][1] = new_label
self._nodes_occupied[(self._members[member][0], new_label)] = True
self._nodes_occupied[(new_label, self._members[member][0])] = True
self._nodes_occupied.pop((self._members[member][0], label))
self._nodes_occupied.pop((label, self._members[member][0]))
def change_member_label(self, *args):
"""
This method changes the label(s) of the specified member(s).
Parameters
==========
The input(s) of this method are tuple(s) of the form (label, new_label)
label: String or Symbol
The label of the member for which the label has
to be changed.
new_label: String or Symbol
The new label of the member.
Examples
========
>>> from sympy.physics.continuum_mechanics.truss import Truss
>>> t = Truss()
>>> t.add_node(('A', 0, 0), ('B', 3, 0), ('D', 5, 0))
>>> t.nodes
[('A', 0, 0), ('B', 3, 0), ('D', 5, 0)]
>>> t.change_node_label(('A', 'C'))
>>> t.nodes
[('C', 0, 0), ('B', 3, 0), ('D', 5, 0)]
>>> t.add_member(('BC', 'B', 'C'), ('BD', 'B', 'D'))
>>> t.members
{'BC': ['B', 'C'], 'BD': ['B', 'D']}
>>> t.change_member_label(('BC', 'BC_new'), ('BD', 'BD_new'))
>>> t.members
{'BC_new': ['B', 'C'], 'BD_new': ['B', 'D']}
"""
for i in args:
label = i[0]
new_label = i[1]
if label not in self._members:
raise ValueError("No such member exists for the Truss")
else:
members_duplicate = list(self._members).copy()
for member in members_duplicate:
if member == label:
self._members[new_label] = [self._members[member][0], self._members[member][1]]
self._members.pop(label)
self._member_lengths[new_label] = self._member_lengths[label]
self._member_lengths.pop(label)
self._internal_forces[new_label] = self._internal_forces[label]
self._internal_forces.pop(label)
def apply_load(self, *args):
"""
This method applies external load(s) at the specified node(s).
Parameters
==========
The input(s) of the method are tuple(s) of the form (location, magnitude, direction).
location: String or Symbol
Label of the Node at which load is applied.
magnitude: Sympifyable
Magnitude of the load applied. It must always be positive and any changes in
the direction of the load are not reflected here.
direction: Sympifyable
The angle, in degrees, that the load vector makes with the horizontal
in the counter-clockwise direction. It takes the values 0 to 360,
inclusive.
Examples
========
>>> from sympy.physics.continuum_mechanics.truss import Truss
>>> from sympy import symbols
>>> t = Truss()
>>> t.add_node(('A', 0, 0), ('B', 3, 0))
>>> P = symbols('P')
>>> t.apply_load(('A', P, 90), ('A', P/2, 45), ('A', P/4, 90))
>>> t.loads
{'A': [[P, 90], [P/2, 45], [P/4, 90]]}
"""
for i in args:
location = i[0]
magnitude = i[1]
direction = i[2]
magnitude = sympify(magnitude)
direction = sympify(direction)
if location not in self._node_coordinates:
raise ValueError("Load must be applied at a known node")
else:
if location in self._loads:
self._loads[location].append([magnitude, direction])
else:
self._loads[location] = [[magnitude, direction]]
def remove_load(self, *args):
"""
This method removes already
present external load(s) at specified node(s).
Parameters
==========
The input(s) of this method are tuple(s) of the form (location, magnitude, direction).
location: String or Symbol
Label of the Node at which load is applied and is to be removed.
magnitude: Sympifyable
Magnitude of the load applied.
direction: Sympifyable
The angle, in degrees, that the load vector makes with the horizontal
in the counter-clockwise direction. It takes the values 0 to 360,
inclusive.
Examples
========
>>> from sympy.physics.continuum_mechanics.truss import Truss
>>> from sympy import symbols
>>> t = Truss()
>>> t.add_node(('A', 0, 0), ('B', 3, 0))
>>> P = symbols('P')
>>> t.apply_load(('A', P, 90), ('A', P/2, 45), ('A', P/4, 90))
>>> t.loads
{'A': [[P, 90], [P/2, 45], [P/4, 90]]}
>>> t.remove_load(('A', P/4, 90), ('A', P/2, 45))
>>> t.loads
{'A': [[P, 90]]}
"""
for i in args:
location = i[0]
magnitude = i[1]
direction = i[2]
magnitude = sympify(magnitude)
direction = sympify(direction)
if location not in self._node_coordinates:
raise ValueError("Load must be removed from a known node")
else:
if [magnitude, direction] not in self._loads[location]:
raise ValueError("No load of this magnitude and direction has been applied at this node")
else:
self._loads[location].remove([magnitude, direction])
if self._loads[location] == []:
self._loads.pop(location)
def apply_support(self, *args):
"""
This method adds a pinned or roller support at specified node(s).
Parameters
==========
The input(s) of this method are of the form (location, type).
location: String or Symbol
Label of the Node at which support is added.
type: String
Type of the support being provided at the node.
Examples
========
>>> from sympy.physics.continuum_mechanics.truss import Truss
>>> t = Truss()
>>> t.add_node(('A', 0, 0), ('B', 3, 0))
>>> t.apply_support(('A', 'pinned'), ('B', 'roller'))
>>> t.supports
{'A': 'pinned', 'B': 'roller'}
"""
for i in args:
location = i[0]
type = i[1]
if location not in self._node_coordinates:
raise ValueError("Support must be added on a known node")
else:
if location not in self._supports:
if type == 'pinned':
self.apply_load((location, Symbol('R_'+str(location)+'_x'), 0))
self.apply_load((location, Symbol('R_'+str(location)+'_y'), 90))
elif type == 'roller':
self.apply_load((location, Symbol('R_'+str(location)+'_y'), 90))
elif self._supports[location] == 'pinned':
if type == 'roller':
self.remove_load((location, Symbol('R_'+str(location)+'_x'), 0))
elif self._supports[location] == 'roller':
if type == 'pinned':
self.apply_load((location, Symbol('R_'+str(location)+'_x'), 0))
self._supports[location] = type
def remove_support(self, *args):
"""
This method removes support from specified node(s.)
Parameters
==========
locations: String or Symbol
Label of the Node(s) at which support is to be removed.
Examples
========
>>> from sympy.physics.continuum_mechanics.truss import Truss
>>> t = Truss()
>>> t.add_node(('A', 0, 0), ('B', 3, 0))
>>> t.apply_support(('A', 'pinned'), ('B', 'roller'))
>>> t.supports
{'A': 'pinned', 'B': 'roller'}
>>> t.remove_support('A','B')
>>> t.supports
{}
"""
for location in args:
if location not in self._node_coordinates:
raise ValueError("No such node exists in the Truss")
elif location not in self._supports:
raise ValueError("No support has been added to the given node")
else:
if self._supports[location] == 'pinned':
self.remove_load((location, Symbol('R_'+str(location)+'_x'), 0))
self.remove_load((location, Symbol('R_'+str(location)+'_y'), 90))
elif self._supports[location] == 'roller':
self.remove_load((location, Symbol('R_'+str(location)+'_y'), 90))
self._supports.pop(location)
def solve(self):
"""
This method solves for all reaction forces of all supports and all internal forces
of all the members in the truss, provided the Truss is solvable.
A Truss is solvable if the following condition is met,
2n >= r + m
Where n is the number of nodes, r is the number of reaction forces, where each pinned
support has 2 reaction forces and each roller has 1, and m is the number of members.
The given condition is derived from the fact that a system of equations is solvable
only when the number of variables is lesser than or equal to the number of equations.
Equilibrium Equations in x and y directions give two equations per node giving 2n number
equations. However, the truss needs to be stable as well and may be unstable if 2n > r + m.
The number of variables is simply the sum of the number of reaction forces and member
forces.
.. note::
The sign convention for the internal forces present in a member revolves around whether each
force is compressive or tensile. While forming equations for each node, internal force due
to a member on the node is assumed to be away from the node i.e. each force is assumed to
be compressive by default. Hence, a positive value for an internal force implies the
presence of compressive force in the member and a negative value implies a tensile force.
Examples
========
>>> from sympy.physics.continuum_mechanics.truss import Truss
>>> t = Truss()
>>> t.add_node(("node_1", 0, 0), ("node_2", 6, 0), ("node_3", 2, 2), ("node_4", 2, 0))
>>> t.add_member(("member_1", "node_1", "node_4"), ("member_2", "node_2", "node_4"), ("member_3", "node_1", "node_3"))
>>> t.add_member(("member_4", "node_2", "node_3"), ("member_5", "node_3", "node_4"))
>>> t.apply_load(("node_4", 10, 270))
>>> t.apply_support(("node_1", "pinned"), ("node_2", "roller"))
>>> t.solve()
>>> t.reaction_loads
{'R_node_1_x': 0, 'R_node_1_y': 20/3, 'R_node_2_y': 10/3}
>>> t.internal_forces
{'member_1': 20/3, 'member_2': 20/3, 'member_3': -20*sqrt(2)/3, 'member_4': -10*sqrt(5)/3, 'member_5': 10}
"""
count_reaction_loads = 0
for node in self._nodes:
if node[0] in self._supports:
if self._supports[node[0]]=='pinned':
count_reaction_loads += 2
elif self._supports[node[0]]=='roller':
count_reaction_loads += 1
if 2*len(self._nodes) != len(self._members) + count_reaction_loads:
raise ValueError("The given truss cannot be solved")
coefficients_matrix = [[0 for i in range(2*len(self._nodes))] for j in range(2*len(self._nodes))]
load_matrix = zeros(2*len(self.nodes), 1)
load_matrix_row = 0
for node in self._nodes:
if node[0] in self._loads:
for load in self._loads[node[0]]:
if load[0]!=Symbol('R_'+str(node[0])+'_x') and load[0]!=Symbol('R_'+str(node[0])+'_y'):
load_matrix[load_matrix_row] -= load[0]*cos(pi*load[1]/180)
load_matrix[load_matrix_row + 1] -= load[0]*sin(pi*load[1]/180)
load_matrix_row += 2
cols = 0
row = 0
for node in self._nodes:
if node[0] in self._supports:
if self._supports[node[0]]=='pinned':
coefficients_matrix[row][cols] += 1
coefficients_matrix[row+1][cols+1] += 1
cols += 2
elif self._supports[node[0]]=='roller':
coefficients_matrix[row+1][cols] += 1
cols += 1
row += 2
for member in self._members:
start = self._members[member][0]
end = self._members[member][1]
length = sqrt((self._node_coordinates[start][0]-self._node_coordinates[end][0])**2 + (self._node_coordinates[start][1]-self._node_coordinates[end][1])**2)
start_index = self._node_labels.index(start)
end_index = self._node_labels.index(end)
horizontal_component_start = (self._node_coordinates[end][0]-self._node_coordinates[start][0])/length
vertical_component_start = (self._node_coordinates[end][1]-self._node_coordinates[start][1])/length
horizontal_component_end = (self._node_coordinates[start][0]-self._node_coordinates[end][0])/length
vertical_component_end = (self._node_coordinates[start][1]-self._node_coordinates[end][1])/length
coefficients_matrix[start_index*2][cols] += horizontal_component_start
coefficients_matrix[start_index*2+1][cols] += vertical_component_start
coefficients_matrix[end_index*2][cols] += horizontal_component_end
coefficients_matrix[end_index*2+1][cols] += vertical_component_end
cols += 1
forces_matrix = (Matrix(coefficients_matrix)**-1)*load_matrix
self._reaction_loads = {}
i = 0
min_load = inf
for node in self._nodes:
if node[0] in self._loads:
for load in self._loads[node[0]]:
if type(load[0]) not in [Symbol, Mul, Add]:
min_load = min(min_load, load[0])
for j in range(len(forces_matrix)):
if type(forces_matrix[j]) not in [Symbol, Mul, Add]:
if abs(forces_matrix[j]/min_load) <1E-10:
forces_matrix[j] = 0
for node in self._nodes:
if node[0] in self._supports:
if self._supports[node[0]]=='pinned':
self._reaction_loads['R_'+str(node[0])+'_x'] = forces_matrix[i]
self._reaction_loads['R_'+str(node[0])+'_y'] = forces_matrix[i+1]
i += 2
elif self._supports[node[0]]=='roller':
self._reaction_loads['R_'+str(node[0])+'_y'] = forces_matrix[i]
i += 1
for member in self._members:
self._internal_forces[member] = forces_matrix[i]
i += 1
return
@doctest_depends_on(modules=('numpy',))
def draw(self, subs_dict=None):
"""
Returns a plot object of the Truss with all its nodes, members,
supports and loads.
.. note::
The user must be careful while entering load values in their
directions. The draw function assumes a sign convention that
is used for plotting loads.
Given a right-handed coordinate system with XYZ coordinates,
the supports are assumed to be such that the reaction forces of a
pinned support is in the +X and +Y direction while those of a
roller support is in the +Y direction. For the load, the range
of angles, one can input goes all the way to 360 degrees which, in the
the plot is the angle that the load vector makes with the positive x-axis in the anticlockwise direction.
For example, for a 90-degree angle, the load will be a vertically
directed along +Y while a 270-degree angle denotes a vertical
load as well but along -Y.
Examples
========
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy.physics.continuum_mechanics.truss import Truss
>>> import math
>>> t = Truss()
>>> t.add_node(("A", -4, 0), ("B", 0, 0), ("C", 4, 0), ("D", 8, 0))
>>> t.add_node(("E", 6, 2/math.sqrt(3)))
>>> t.add_node(("F", 2, 2*math.sqrt(3)))
>>> t.add_node(("G", -2, 2/math.sqrt(3)))
>>> t.add_member(("AB","A","B"), ("BC","B","C"), ("CD","C","D"))
>>> t.add_member(("AG","A","G"), ("GB","G","B"), ("GF","G","F"))
>>> t.add_member(("BF","B","F"), ("FC","F","C"), ("CE","C","E"))
>>> t.add_member(("FE","F","E"), ("DE","D","E"))
>>> t.apply_support(("A","pinned"), ("D","roller"))
>>> t.apply_load(("G", 3, 90), ("E", 3, 90), ("F", 2, 90))
>>> p = t.draw()
>>> p # doctest: +ELLIPSIS
Plot object containing:
[0]: cartesian line: 1 for x over (1.0, 1.0)
...
>>> p.show()
"""
if not numpy:
raise ImportError("To use this function numpy module is required")
x = Symbol('x')
markers = []
annotations = []
rectangles = []
node_markers = self._draw_nodes(subs_dict)
markers += node_markers
member_rectangles = self._draw_members()
rectangles += member_rectangles
support_markers = self._draw_supports()
markers += support_markers
load_annotations = self._draw_loads()
annotations += load_annotations
xmax = -INF
xmin = INF
ymax = -INF
ymin = INF
for node in self._node_coordinates:
xmax = max(xmax, self._node_coordinates[node][0])
xmin = min(xmin, self._node_coordinates[node][0])
ymax = max(ymax, self._node_coordinates[node][1])
ymin = min(ymin, self._node_coordinates[node][1])
lim = max(xmax*1.1-xmin*0.8+1, ymax*1.1-ymin*0.8+1)
if lim==xmax*1.1-xmin*0.8+1:
sing_plot = plot(1, (x, 1, 1), markers=markers, show=False, annotations=annotations, xlim=(xmin-0.05*lim, xmax*1.1), ylim=(xmin-0.05*lim, xmax*1.1), axis=False, rectangles=rectangles)
else:
sing_plot = plot(1, (x, 1, 1), markers=markers, show=False, annotations=annotations, xlim=(ymin-0.05*lim, ymax*1.1), ylim=(ymin-0.05*lim, ymax*1.1), axis=False, rectangles=rectangles)
return sing_plot
def _draw_nodes(self, subs_dict):
node_markers = []
for node in self._node_coordinates:
if (type(self._node_coordinates[node][0]) in (Symbol, Quantity)):
if self._node_coordinates[node][0] in subs_dict:
self._node_coordinates[node][0] = subs_dict[self._node_coordinates[node][0]]
else:
raise ValueError("provided substituted dictionary is not adequate")
elif (type(self._node_coordinates[node][0]) == Mul):
objects = self._node_coordinates[node][0].as_coeff_Mul()
for object in objects:
if type(object) in (Symbol, Quantity):
if subs_dict==None or object not in subs_dict:
raise ValueError("provided substituted dictionary is not adequate")
else:
self._node_coordinates[node][0] /= object
self._node_coordinates[node][0] *= subs_dict[object]
if (type(self._node_coordinates[node][1]) in (Symbol, Quantity)):
if self._node_coordinates[node][1] in subs_dict:
self._node_coordinates[node][1] = subs_dict[self._node_coordinates[node][1]]
else:
raise ValueError("provided substituted dictionary is not adequate")
elif (type(self._node_coordinates[node][1]) == Mul):
objects = self._node_coordinates[node][1].as_coeff_Mul()
for object in objects:
if type(object) in (Symbol, Quantity):
if subs_dict==None or object not in subs_dict:
raise ValueError("provided substituted dictionary is not adequate")
else:
self._node_coordinates[node][1] /= object
self._node_coordinates[node][1] *= subs_dict[object]
for node in self._node_coordinates:
node_markers.append(
{
'args':[[self._node_coordinates[node][0]], [self._node_coordinates[node][1]]],
'marker':'o',
'markersize':5,
'color':'black'
}
)
return node_markers
def _draw_members(self):
member_rectangles = []
xmax = -INF
xmin = INF
ymax = -INF
ymin = INF
for node in self._node_coordinates:
xmax = max(xmax, self._node_coordinates[node][0])
xmin = min(xmin, self._node_coordinates[node][0])
ymax = max(ymax, self._node_coordinates[node][1])
ymin = min(ymin, self._node_coordinates[node][1])
if abs(1.1*xmax-0.8*xmin)>abs(1.1*ymax-0.8*ymin):
max_diff = 1.1*xmax-0.8*xmin
else:
max_diff = 1.1*ymax-0.8*ymin
for member in self._members:
x1 = self._node_coordinates[self._members[member][0]][0]
y1 = self._node_coordinates[self._members[member][0]][1]
x2 = self._node_coordinates[self._members[member][1]][0]
y2 = self._node_coordinates[self._members[member][1]][1]
if x2!=x1 and y2!=y1:
if x2>x1:
member_rectangles.append(
{
'xy':(x1-0.005*max_diff*cos(pi/4+atan((y2-y1)/(x2-x1)))/2, y1-0.005*max_diff*sin(pi/4+atan((y2-y1)/(x2-x1)))/2),
'width':sqrt((x1-x2)**2+(y1-y2)**2)+0.005*max_diff/math.sqrt(2),
'height':0.005*max_diff,
'angle':180*atan((y2-y1)/(x2-x1))/pi,
'color':'brown'
}
)
else:
member_rectangles.append(
{
'xy':(x2-0.005*max_diff*cos(pi/4+atan((y2-y1)/(x2-x1)))/2, y2-0.005*max_diff*sin(pi/4+atan((y2-y1)/(x2-x1)))/2),
'width':sqrt((x1-x2)**2+(y1-y2)**2)+0.005*max_diff/math.sqrt(2),
'height':0.005*max_diff,
'angle':180*atan((y2-y1)/(x2-x1))/pi,
'color':'brown'
}
)
elif y2==y1:
if x2>x1:
member_rectangles.append(
{
'xy':(x1-0.005*max_diff/2, y1-0.005*max_diff/2),
'width':sqrt((x1-x2)**2+(y1-y2)**2),
'height':0.005*max_diff,
'angle':90*(1-math.copysign(1, x2-x1)),
'color':'brown'
}
)
else:
member_rectangles.append(
{
'xy':(x1-0.005*max_diff/2, y1-0.005*max_diff/2),
'width':sqrt((x1-x2)**2+(y1-y2)**2),
'height':-0.005*max_diff,
'angle':90*(1-math.copysign(1, x2-x1)),
'color':'brown'
}
)
else:
if y1<y2:
member_rectangles.append(
{
'xy':(x1-0.005*max_diff/2, y1-0.005*max_diff/2),
'width':sqrt((x1-x2)**2+(y1-y2)**2)+0.005*max_diff/2,
'height':0.005*max_diff,
'angle':90*math.copysign(1, y2-y1),
'color':'brown'
}
)
else:
member_rectangles.append(
{
'xy':(x2-0.005*max_diff/2, y2-0.005*max_diff/2),
'width':-(sqrt((x1-x2)**2+(y1-y2)**2)+0.005*max_diff/2),
'height':0.005*max_diff,
'angle':90*math.copysign(1, y2-y1),
'color':'brown'
}
)
return member_rectangles
def _draw_supports(self):
support_markers = []
xmax = -INF
xmin = INF
ymax = -INF
ymin = INF
for node in self._node_coordinates:
xmax = max(xmax, self._node_coordinates[node][0])
xmin = min(xmin, self._node_coordinates[node][0])
ymax = max(ymax, self._node_coordinates[node][1])
ymin = min(ymin, self._node_coordinates[node][1])
if abs(1.1*xmax-0.8*xmin)>abs(1.1*ymax-0.8*ymin):
max_diff = 1.1*xmax-0.8*xmin
else:
max_diff = 1.1*ymax-0.8*ymin
for node in self._supports:
if self._supports[node]=='pinned':
support_markers.append(
{
'args':[
[self._node_coordinates[node][0]],
[self._node_coordinates[node][1]]
],
'marker':6,
'markersize':15,
'color':'black',
'markerfacecolor':'none'
}
)
support_markers.append(
{
'args':[
[self._node_coordinates[node][0]],
[self._node_coordinates[node][1]-0.035*max_diff]
],
'marker':'_',
'markersize':14,
'color':'black'
}
)
elif self._supports[node]=='roller':
support_markers.append(
{
'args':[
[self._node_coordinates[node][0]],
[self._node_coordinates[node][1]-0.02*max_diff]
],
'marker':'o',
'markersize':11,
'color':'black',
'markerfacecolor':'none'
}
)
support_markers.append(
{
'args':[
[self._node_coordinates[node][0]],
[self._node_coordinates[node][1]-0.0375*max_diff]
],
'marker':'_',
'markersize':14,
'color':'black'
}
)
return support_markers
def _draw_loads(self):
load_annotations = []
xmax = -INF
xmin = INF
ymax = -INF
ymin = INF
for node in self._node_coordinates:
xmax = max(xmax, self._node_coordinates[node][0])
xmin = min(xmin, self._node_coordinates[node][0])
ymax = max(ymax, self._node_coordinates[node][1])
ymin = min(ymin, self._node_coordinates[node][1])
if abs(1.1*xmax-0.8*xmin)>abs(1.1*ymax-0.8*ymin):
max_diff = 1.1*xmax-0.8*xmin+5
else:
max_diff = 1.1*ymax-0.8*ymin+5
for node in self._loads:
for load in self._loads[node]:
if load[0] in [Symbol('R_'+str(node)+'_x'), Symbol('R_'+str(node)+'_y')]:
continue
x = self._node_coordinates[node][0]
y = self._node_coordinates[node][1]
load_annotations.append(
{
'text':'',
'xy':(
x-math.cos(pi*load[1]/180)*(max_diff/100),
y-math.sin(pi*load[1]/180)*(max_diff/100)
),
'xytext':(
x-(max_diff/100+abs(xmax-xmin)+abs(ymax-ymin))*math.cos(pi*load[1]/180)/20,
y-(max_diff/100+abs(xmax-xmin)+abs(ymax-ymin))*math.sin(pi*load[1]/180)/20
),
'arrowprops':{'width':1.5, 'headlength':5, 'headwidth':5, 'facecolor':'black'}
}
)
return load_annotations
PK ]ZZZ�20-� � ! sympy/physics/control/__init__.pyfrom .lti import (TransferFunction, Series, MIMOSeries, Parallel, MIMOParallel,
Feedback, MIMOFeedback, TransferFunctionMatrix, StateSpace, gbt, bilinear, forward_diff,
backward_diff, phase_margin, gain_margin)
from .control_plots import (pole_zero_numerical_data, pole_zero_plot, step_response_numerical_data,
step_response_plot, impulse_response_numerical_data, impulse_response_plot, ramp_response_numerical_data,
ramp_response_plot, bode_magnitude_numerical_data, bode_phase_numerical_data, bode_magnitude_plot,
bode_phase_plot, bode_plot)
__all__ = ['TransferFunction', 'Series', 'MIMOSeries', 'Parallel',
'MIMOParallel', 'Feedback', 'MIMOFeedback', 'TransferFunctionMatrix', 'StateSpace',
'gbt', 'bilinear', 'forward_diff', 'backward_diff', 'phase_margin', 'gain_margin',
'pole_zero_numerical_data', 'pole_zero_plot', 'step_response_numerical_data',
'step_response_plot', 'impulse_response_numerical_data', 'impulse_response_plot',
'ramp_response_numerical_data', 'ramp_response_plot',
'bode_magnitude_numerical_data', 'bode_phase_numerical_data',
'bode_magnitude_plot', 'bode_phase_plot', 'bode_plot']
PK ]ZZZ{��O� O� & sympy/physics/control/control_plots.pyfrom sympy.core.numbers import I, pi
from sympy.functions.elementary.exponential import (exp, log)
from sympy.polys.partfrac import apart
from sympy.core.symbol import Dummy
from sympy.external import import_module
from sympy.functions import arg, Abs
from sympy.integrals.laplace import _fast_inverse_laplace
from sympy.physics.control.lti import SISOLinearTimeInvariant
from sympy.plotting.series import LineOver1DRangeSeries
from sympy.polys.polytools import Poly
from sympy.printing.latex import latex
__all__ = ['pole_zero_numerical_data', 'pole_zero_plot',
'step_response_numerical_data', 'step_response_plot',
'impulse_response_numerical_data', 'impulse_response_plot',
'ramp_response_numerical_data', 'ramp_response_plot',
'bode_magnitude_numerical_data', 'bode_phase_numerical_data',
'bode_magnitude_plot', 'bode_phase_plot', 'bode_plot']
matplotlib = import_module(
'matplotlib', import_kwargs={'fromlist': ['pyplot']},
catch=(RuntimeError,))
numpy = import_module('numpy')
if matplotlib:
plt = matplotlib.pyplot
if numpy:
np = numpy # Matplotlib already has numpy as a compulsory dependency. No need to install it separately.
def _check_system(system):
"""Function to check whether the dynamical system passed for plots is
compatible or not."""
if not isinstance(system, SISOLinearTimeInvariant):
raise NotImplementedError("Only SISO LTI systems are currently supported.")
sys = system.to_expr()
len_free_symbols = len(sys.free_symbols)
if len_free_symbols > 1:
raise ValueError("Extra degree of freedom found. Make sure"
" that there are no free symbols in the dynamical system other"
" than the variable of Laplace transform.")
if sys.has(exp):
# Should test that exp is not part of a constant, in which case
# no exception is required, compare exp(s) with s*exp(1)
raise NotImplementedError("Time delay terms are not supported.")
def pole_zero_numerical_data(system):
"""
Returns the numerical data of poles and zeros of the system.
It is internally used by ``pole_zero_plot`` to get the data
for plotting poles and zeros. Users can use this data to further
analyse the dynamics of the system or plot using a different
backend/plotting-module.
Parameters
==========
system : SISOLinearTimeInvariant
The system for which the pole-zero data is to be computed.
Returns
=======
tuple : (zeros, poles)
zeros = Zeros of the system. NumPy array of complex numbers.
poles = Poles of the system. NumPy array of complex numbers.
Raises
======
NotImplementedError
When a SISO LTI system is not passed.
When time delay terms are present in the system.
ValueError
When more than one free symbol is present in the system.
The only variable in the transfer function should be
the variable of the Laplace transform.
Examples
========
>>> from sympy.abc import s
>>> from sympy.physics.control.lti import TransferFunction
>>> from sympy.physics.control.control_plots import pole_zero_numerical_data
>>> tf1 = TransferFunction(s**2 + 1, s**4 + 4*s**3 + 6*s**2 + 5*s + 2, s)
>>> pole_zero_numerical_data(tf1) # doctest: +SKIP
([-0.+1.j 0.-1.j], [-2. +0.j -0.5+0.8660254j -0.5-0.8660254j -1. +0.j ])
See Also
========
pole_zero_plot
"""
_check_system(system)
system = system.doit() # Get the equivalent TransferFunction object.
num_poly = Poly(system.num, system.var).all_coeffs()
den_poly = Poly(system.den, system.var).all_coeffs()
num_poly = np.array(num_poly, dtype=np.complex128)
den_poly = np.array(den_poly, dtype=np.complex128)
zeros = np.roots(num_poly)
poles = np.roots(den_poly)
return zeros, poles
def pole_zero_plot(system, pole_color='blue', pole_markersize=10,
zero_color='orange', zero_markersize=7, grid=True, show_axes=True,
show=True, **kwargs):
r"""
Returns the Pole-Zero plot (also known as PZ Plot or PZ Map) of a system.
A Pole-Zero plot is a graphical representation of a system's poles and
zeros. It is plotted on a complex plane, with circular markers representing
the system's zeros and 'x' shaped markers representing the system's poles.
Parameters
==========
system : SISOLinearTimeInvariant type systems
The system for which the pole-zero plot is to be computed.
pole_color : str, tuple, optional
The color of the pole points on the plot. Default color
is blue. The color can be provided as a matplotlib color string,
or a 3-tuple of floats each in the 0-1 range.
pole_markersize : Number, optional
The size of the markers used to mark the poles in the plot.
Default pole markersize is 10.
zero_color : str, tuple, optional
The color of the zero points on the plot. Default color
is orange. The color can be provided as a matplotlib color string,
or a 3-tuple of floats each in the 0-1 range.
zero_markersize : Number, optional
The size of the markers used to mark the zeros in the plot.
Default zero markersize is 7.
grid : boolean, optional
If ``True``, the plot will have a grid. Defaults to True.
show_axes : boolean, optional
If ``True``, the coordinate axes will be shown. Defaults to False.
show : boolean, optional
If ``True``, the plot will be displayed otherwise
the equivalent matplotlib ``plot`` object will be returned.
Defaults to True.
Examples
========
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy.abc import s
>>> from sympy.physics.control.lti import TransferFunction
>>> from sympy.physics.control.control_plots import pole_zero_plot
>>> tf1 = TransferFunction(s**2 + 1, s**4 + 4*s**3 + 6*s**2 + 5*s + 2, s)
>>> pole_zero_plot(tf1) # doctest: +SKIP
See Also
========
pole_zero_numerical_data
References
==========
.. [1] https://en.wikipedia.org/wiki/Pole%E2%80%93zero_plot
"""
zeros, poles = pole_zero_numerical_data(system)
zero_real = np.real(zeros)
zero_imag = np.imag(zeros)
pole_real = np.real(poles)
pole_imag = np.imag(poles)
plt.plot(pole_real, pole_imag, 'x', mfc='none',
markersize=pole_markersize, color=pole_color)
plt.plot(zero_real, zero_imag, 'o', markersize=zero_markersize,
color=zero_color)
plt.xlabel('Real Axis')
plt.ylabel('Imaginary Axis')
plt.title(f'Poles and Zeros of ${latex(system)}$', pad=20)
if grid:
plt.grid()
if show_axes:
plt.axhline(0, color='black')
plt.axvline(0, color='black')
if show:
plt.show()
return
return plt
def step_response_numerical_data(system, prec=8, lower_limit=0,
upper_limit=10, **kwargs):
"""
Returns the numerical values of the points in the step response plot
of a SISO continuous-time system. By default, adaptive sampling
is used. If the user wants to instead get an uniformly
sampled response, then ``adaptive`` kwarg should be passed ``False``
and ``n`` must be passed as additional kwargs.
Refer to the parameters of class :class:`sympy.plotting.series.LineOver1DRangeSeries`
for more details.
Parameters
==========
system : SISOLinearTimeInvariant
The system for which the unit step response data is to be computed.
prec : int, optional
The decimal point precision for the point coordinate values.
Defaults to 8.
lower_limit : Number, optional
The lower limit of the plot range. Defaults to 0.
upper_limit : Number, optional
The upper limit of the plot range. Defaults to 10.
kwargs :
Additional keyword arguments are passed to the underlying
:class:`sympy.plotting.series.LineOver1DRangeSeries` class.
Returns
=======
tuple : (x, y)
x = Time-axis values of the points in the step response. NumPy array.
y = Amplitude-axis values of the points in the step response. NumPy array.
Raises
======
NotImplementedError
When a SISO LTI system is not passed.
When time delay terms are present in the system.
ValueError
When more than one free symbol is present in the system.
The only variable in the transfer function should be
the variable of the Laplace transform.
When ``lower_limit`` parameter is less than 0.
Examples
========
>>> from sympy.abc import s
>>> from sympy.physics.control.lti import TransferFunction
>>> from sympy.physics.control.control_plots import step_response_numerical_data
>>> tf1 = TransferFunction(s, s**2 + 5*s + 8, s)
>>> step_response_numerical_data(tf1) # doctest: +SKIP
([0.0, 0.025413462339411542, 0.0484508722725343, ... , 9.670250533855183, 9.844291913708725, 10.0],
[0.0, 0.023844582399907256, 0.042894276802320226, ..., 6.828770759094287e-12, 6.456457160755703e-12])
See Also
========
step_response_plot
"""
if lower_limit < 0:
raise ValueError("Lower limit of time must be greater "
"than or equal to zero.")
_check_system(system)
_x = Dummy("x")
expr = system.to_expr()/(system.var)
expr = apart(expr, system.var, full=True)
_y = _fast_inverse_laplace(expr, system.var, _x).evalf(prec)
return LineOver1DRangeSeries(_y, (_x, lower_limit, upper_limit),
**kwargs).get_points()
def step_response_plot(system, color='b', prec=8, lower_limit=0,
upper_limit=10, show_axes=False, grid=True, show=True, **kwargs):
r"""
Returns the unit step response of a continuous-time system. It is
the response of the system when the input signal is a step function.
Parameters
==========
system : SISOLinearTimeInvariant type
The LTI SISO system for which the Step Response is to be computed.
color : str, tuple, optional
The color of the line. Default is Blue.
show : boolean, optional
If ``True``, the plot will be displayed otherwise
the equivalent matplotlib ``plot`` object will be returned.
Defaults to True.
lower_limit : Number, optional
The lower limit of the plot range. Defaults to 0.
upper_limit : Number, optional
The upper limit of the plot range. Defaults to 10.
prec : int, optional
The decimal point precision for the point coordinate values.
Defaults to 8.
show_axes : boolean, optional
If ``True``, the coordinate axes will be shown. Defaults to False.
grid : boolean, optional
If ``True``, the plot will have a grid. Defaults to True.
Examples
========
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy.abc import s
>>> from sympy.physics.control.lti import TransferFunction
>>> from sympy.physics.control.control_plots import step_response_plot
>>> tf1 = TransferFunction(8*s**2 + 18*s + 32, s**3 + 6*s**2 + 14*s + 24, s)
>>> step_response_plot(tf1) # doctest: +SKIP
See Also
========
impulse_response_plot, ramp_response_plot
References
==========
.. [1] https://www.mathworks.com/help/control/ref/lti.step.html
"""
x, y = step_response_numerical_data(system, prec=prec,
lower_limit=lower_limit, upper_limit=upper_limit, **kwargs)
plt.plot(x, y, color=color)
plt.xlabel('Time (s)')
plt.ylabel('Amplitude')
plt.title(f'Unit Step Response of ${latex(system)}$', pad=20)
if grid:
plt.grid()
if show_axes:
plt.axhline(0, color='black')
plt.axvline(0, color='black')
if show:
plt.show()
return
return plt
def impulse_response_numerical_data(system, prec=8, lower_limit=0,
upper_limit=10, **kwargs):
"""
Returns the numerical values of the points in the impulse response plot
of a SISO continuous-time system. By default, adaptive sampling
is used. If the user wants to instead get an uniformly
sampled response, then ``adaptive`` kwarg should be passed ``False``
and ``n`` must be passed as additional kwargs.
Refer to the parameters of class :class:`sympy.plotting.series.LineOver1DRangeSeries`
for more details.
Parameters
==========
system : SISOLinearTimeInvariant
The system for which the impulse response data is to be computed.
prec : int, optional
The decimal point precision for the point coordinate values.
Defaults to 8.
lower_limit : Number, optional
The lower limit of the plot range. Defaults to 0.
upper_limit : Number, optional
The upper limit of the plot range. Defaults to 10.
kwargs :
Additional keyword arguments are passed to the underlying
:class:`sympy.plotting.series.LineOver1DRangeSeries` class.
Returns
=======
tuple : (x, y)
x = Time-axis values of the points in the impulse response. NumPy array.
y = Amplitude-axis values of the points in the impulse response. NumPy array.
Raises
======
NotImplementedError
When a SISO LTI system is not passed.
When time delay terms are present in the system.
ValueError
When more than one free symbol is present in the system.
The only variable in the transfer function should be
the variable of the Laplace transform.
When ``lower_limit`` parameter is less than 0.
Examples
========
>>> from sympy.abc import s
>>> from sympy.physics.control.lti import TransferFunction
>>> from sympy.physics.control.control_plots import impulse_response_numerical_data
>>> tf1 = TransferFunction(s, s**2 + 5*s + 8, s)
>>> impulse_response_numerical_data(tf1) # doctest: +SKIP
([0.0, 0.06616480200395854,... , 9.854500743565858, 10.0],
[0.9999999799999999, 0.7042848373025861,...,7.170748906965121e-13, -5.1901263495547205e-12])
See Also
========
impulse_response_plot
"""
if lower_limit < 0:
raise ValueError("Lower limit of time must be greater "
"than or equal to zero.")
_check_system(system)
_x = Dummy("x")
expr = system.to_expr()
expr = apart(expr, system.var, full=True)
_y = _fast_inverse_laplace(expr, system.var, _x).evalf(prec)
return LineOver1DRangeSeries(_y, (_x, lower_limit, upper_limit),
**kwargs).get_points()
def impulse_response_plot(system, color='b', prec=8, lower_limit=0,
upper_limit=10, show_axes=False, grid=True, show=True, **kwargs):
r"""
Returns the unit impulse response (Input is the Dirac-Delta Function) of a
continuous-time system.
Parameters
==========
system : SISOLinearTimeInvariant type
The LTI SISO system for which the Impulse Response is to be computed.
color : str, tuple, optional
The color of the line. Default is Blue.
show : boolean, optional
If ``True``, the plot will be displayed otherwise
the equivalent matplotlib ``plot`` object will be returned.
Defaults to True.
lower_limit : Number, optional
The lower limit of the plot range. Defaults to 0.
upper_limit : Number, optional
The upper limit of the plot range. Defaults to 10.
prec : int, optional
The decimal point precision for the point coordinate values.
Defaults to 8.
show_axes : boolean, optional
If ``True``, the coordinate axes will be shown. Defaults to False.
grid : boolean, optional
If ``True``, the plot will have a grid. Defaults to True.
Examples
========
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy.abc import s
>>> from sympy.physics.control.lti import TransferFunction
>>> from sympy.physics.control.control_plots import impulse_response_plot
>>> tf1 = TransferFunction(8*s**2 + 18*s + 32, s**3 + 6*s**2 + 14*s + 24, s)
>>> impulse_response_plot(tf1) # doctest: +SKIP
See Also
========
step_response_plot, ramp_response_plot
References
==========
.. [1] https://www.mathworks.com/help/control/ref/dynamicsystem.impulse.html
"""
x, y = impulse_response_numerical_data(system, prec=prec,
lower_limit=lower_limit, upper_limit=upper_limit, **kwargs)
plt.plot(x, y, color=color)
plt.xlabel('Time (s)')
plt.ylabel('Amplitude')
plt.title(f'Impulse Response of ${latex(system)}$', pad=20)
if grid:
plt.grid()
if show_axes:
plt.axhline(0, color='black')
plt.axvline(0, color='black')
if show:
plt.show()
return
return plt
def ramp_response_numerical_data(system, slope=1, prec=8,
lower_limit=0, upper_limit=10, **kwargs):
"""
Returns the numerical values of the points in the ramp response plot
of a SISO continuous-time system. By default, adaptive sampling
is used. If the user wants to instead get an uniformly
sampled response, then ``adaptive`` kwarg should be passed ``False``
and ``n`` must be passed as additional kwargs.
Refer to the parameters of class :class:`sympy.plotting.series.LineOver1DRangeSeries`
for more details.
Parameters
==========
system : SISOLinearTimeInvariant
The system for which the ramp response data is to be computed.
slope : Number, optional
The slope of the input ramp function. Defaults to 1.
prec : int, optional
The decimal point precision for the point coordinate values.
Defaults to 8.
lower_limit : Number, optional
The lower limit of the plot range. Defaults to 0.
upper_limit : Number, optional
The upper limit of the plot range. Defaults to 10.
kwargs :
Additional keyword arguments are passed to the underlying
:class:`sympy.plotting.series.LineOver1DRangeSeries` class.
Returns
=======
tuple : (x, y)
x = Time-axis values of the points in the ramp response plot. NumPy array.
y = Amplitude-axis values of the points in the ramp response plot. NumPy array.
Raises
======
NotImplementedError
When a SISO LTI system is not passed.
When time delay terms are present in the system.
ValueError
When more than one free symbol is present in the system.
The only variable in the transfer function should be
the variable of the Laplace transform.
When ``lower_limit`` parameter is less than 0.
When ``slope`` is negative.
Examples
========
>>> from sympy.abc import s
>>> from sympy.physics.control.lti import TransferFunction
>>> from sympy.physics.control.control_plots import ramp_response_numerical_data
>>> tf1 = TransferFunction(s, s**2 + 5*s + 8, s)
>>> ramp_response_numerical_data(tf1) # doctest: +SKIP
(([0.0, 0.12166980856813935,..., 9.861246379582118, 10.0],
[1.4504508011325967e-09, 0.006046440489058766,..., 0.12499999999568202, 0.12499999999661349]))
See Also
========
ramp_response_plot
"""
if slope < 0:
raise ValueError("Slope must be greater than or equal"
" to zero.")
if lower_limit < 0:
raise ValueError("Lower limit of time must be greater "
"than or equal to zero.")
_check_system(system)
_x = Dummy("x")
expr = (slope*system.to_expr())/((system.var)**2)
expr = apart(expr, system.var, full=True)
_y = _fast_inverse_laplace(expr, system.var, _x).evalf(prec)
return LineOver1DRangeSeries(_y, (_x, lower_limit, upper_limit),
**kwargs).get_points()
def ramp_response_plot(system, slope=1, color='b', prec=8, lower_limit=0,
upper_limit=10, show_axes=False, grid=True, show=True, **kwargs):
r"""
Returns the ramp response of a continuous-time system.
Ramp function is defined as the straight line
passing through origin ($f(x) = mx$). The slope of
the ramp function can be varied by the user and
the default value is 1.
Parameters
==========
system : SISOLinearTimeInvariant type
The LTI SISO system for which the Ramp Response is to be computed.
slope : Number, optional
The slope of the input ramp function. Defaults to 1.
color : str, tuple, optional
The color of the line. Default is Blue.
show : boolean, optional
If ``True``, the plot will be displayed otherwise
the equivalent matplotlib ``plot`` object will be returned.
Defaults to True.
lower_limit : Number, optional
The lower limit of the plot range. Defaults to 0.
upper_limit : Number, optional
The upper limit of the plot range. Defaults to 10.
prec : int, optional
The decimal point precision for the point coordinate values.
Defaults to 8.
show_axes : boolean, optional
If ``True``, the coordinate axes will be shown. Defaults to False.
grid : boolean, optional
If ``True``, the plot will have a grid. Defaults to True.
Examples
========
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy.abc import s
>>> from sympy.physics.control.lti import TransferFunction
>>> from sympy.physics.control.control_plots import ramp_response_plot
>>> tf1 = TransferFunction(s, (s+4)*(s+8), s)
>>> ramp_response_plot(tf1, upper_limit=2) # doctest: +SKIP
See Also
========
step_response_plot, impulse_response_plot
References
==========
.. [1] https://en.wikipedia.org/wiki/Ramp_function
"""
x, y = ramp_response_numerical_data(system, slope=slope, prec=prec,
lower_limit=lower_limit, upper_limit=upper_limit, **kwargs)
plt.plot(x, y, color=color)
plt.xlabel('Time (s)')
plt.ylabel('Amplitude')
plt.title(f'Ramp Response of ${latex(system)}$ [Slope = {slope}]', pad=20)
if grid:
plt.grid()
if show_axes:
plt.axhline(0, color='black')
plt.axvline(0, color='black')
if show:
plt.show()
return
return plt
def bode_magnitude_numerical_data(system, initial_exp=-5, final_exp=5, freq_unit='rad/sec', **kwargs):
"""
Returns the numerical data of the Bode magnitude plot of the system.
It is internally used by ``bode_magnitude_plot`` to get the data
for plotting Bode magnitude plot. Users can use this data to further
analyse the dynamics of the system or plot using a different
backend/plotting-module.
Parameters
==========
system : SISOLinearTimeInvariant
The system for which the data is to be computed.
initial_exp : Number, optional
The initial exponent of 10 of the semilog plot. Defaults to -5.
final_exp : Number, optional
The final exponent of 10 of the semilog plot. Defaults to 5.
freq_unit : string, optional
User can choose between ``'rad/sec'`` (radians/second) and ``'Hz'`` (Hertz) as frequency units.
Returns
=======
tuple : (x, y)
x = x-axis values of the Bode magnitude plot.
y = y-axis values of the Bode magnitude plot.
Raises
======
NotImplementedError
When a SISO LTI system is not passed.
When time delay terms are present in the system.
ValueError
When more than one free symbol is present in the system.
The only variable in the transfer function should be
the variable of the Laplace transform.
When incorrect frequency units are given as input.
Examples
========
>>> from sympy.abc import s
>>> from sympy.physics.control.lti import TransferFunction
>>> from sympy.physics.control.control_plots import bode_magnitude_numerical_data
>>> tf1 = TransferFunction(s**2 + 1, s**4 + 4*s**3 + 6*s**2 + 5*s + 2, s)
>>> bode_magnitude_numerical_data(tf1) # doctest: +SKIP
([1e-05, 1.5148378120533502e-05,..., 68437.36188804005, 100000.0],
[-6.020599914256786, -6.0205999155219505,..., -193.4117304087953, -200.00000000260573])
See Also
========
bode_magnitude_plot, bode_phase_numerical_data
"""
_check_system(system)
expr = system.to_expr()
freq_units = ('rad/sec', 'Hz')
if freq_unit not in freq_units:
raise ValueError('Only "rad/sec" and "Hz" are accepted frequency units.')
_w = Dummy("w", real=True)
if freq_unit == 'Hz':
repl = I*_w*2*pi
else:
repl = I*_w
w_expr = expr.subs({system.var: repl})
mag = 20*log(Abs(w_expr), 10)
x, y = LineOver1DRangeSeries(mag,
(_w, 10**initial_exp, 10**final_exp), xscale='log', **kwargs).get_points()
return x, y
def bode_magnitude_plot(system, initial_exp=-5, final_exp=5,
color='b', show_axes=False, grid=True, show=True, freq_unit='rad/sec', **kwargs):
r"""
Returns the Bode magnitude plot of a continuous-time system.
See ``bode_plot`` for all the parameters.
"""
x, y = bode_magnitude_numerical_data(system, initial_exp=initial_exp,
final_exp=final_exp, freq_unit=freq_unit)
plt.plot(x, y, color=color, **kwargs)
plt.xscale('log')
plt.xlabel('Frequency (%s) [Log Scale]' % freq_unit)
plt.ylabel('Magnitude (dB)')
plt.title(f'Bode Plot (Magnitude) of ${latex(system)}$', pad=20)
if grid:
plt.grid(True)
if show_axes:
plt.axhline(0, color='black')
plt.axvline(0, color='black')
if show:
plt.show()
return
return plt
def bode_phase_numerical_data(system, initial_exp=-5, final_exp=5, freq_unit='rad/sec', phase_unit='rad', phase_unwrap = True, **kwargs):
"""
Returns the numerical data of the Bode phase plot of the system.
It is internally used by ``bode_phase_plot`` to get the data
for plotting Bode phase plot. Users can use this data to further
analyse the dynamics of the system or plot using a different
backend/plotting-module.
Parameters
==========
system : SISOLinearTimeInvariant
The system for which the Bode phase plot data is to be computed.
initial_exp : Number, optional
The initial exponent of 10 of the semilog plot. Defaults to -5.
final_exp : Number, optional
The final exponent of 10 of the semilog plot. Defaults to 5.
freq_unit : string, optional
User can choose between ``'rad/sec'`` (radians/second) and '``'Hz'`` (Hertz) as frequency units.
phase_unit : string, optional
User can choose between ``'rad'`` (radians) and ``'deg'`` (degree) as phase units.
phase_unwrap : bool, optional
Set to ``True`` by default.
Returns
=======
tuple : (x, y)
x = x-axis values of the Bode phase plot.
y = y-axis values of the Bode phase plot.
Raises
======
NotImplementedError
When a SISO LTI system is not passed.
When time delay terms are present in the system.
ValueError
When more than one free symbol is present in the system.
The only variable in the transfer function should be
the variable of the Laplace transform.
When incorrect frequency or phase units are given as input.
Examples
========
>>> from sympy.abc import s
>>> from sympy.physics.control.lti import TransferFunction
>>> from sympy.physics.control.control_plots import bode_phase_numerical_data
>>> tf1 = TransferFunction(s**2 + 1, s**4 + 4*s**3 + 6*s**2 + 5*s + 2, s)
>>> bode_phase_numerical_data(tf1) # doctest: +SKIP
([1e-05, 1.4472354033813751e-05, 2.035581932165858e-05,..., 47577.3248186011, 67884.09326036123, 100000.0],
[-2.5000000000291665e-05, -3.6180885085e-05, -5.08895483066e-05,...,-3.1415085799262523, -3.14155265358979])
See Also
========
bode_magnitude_plot, bode_phase_numerical_data
"""
_check_system(system)
expr = system.to_expr()
freq_units = ('rad/sec', 'Hz')
phase_units = ('rad', 'deg')
if freq_unit not in freq_units:
raise ValueError('Only "rad/sec" and "Hz" are accepted frequency units.')
if phase_unit not in phase_units:
raise ValueError('Only "rad" and "deg" are accepted phase units.')
_w = Dummy("w", real=True)
if freq_unit == 'Hz':
repl = I*_w*2*pi
else:
repl = I*_w
w_expr = expr.subs({system.var: repl})
if phase_unit == 'deg':
phase = arg(w_expr)*180/pi
else:
phase = arg(w_expr)
x, y = LineOver1DRangeSeries(phase,
(_w, 10**initial_exp, 10**final_exp), xscale='log', **kwargs).get_points()
half = None
if phase_unwrap:
if(phase_unit == 'rad'):
half = pi
elif(phase_unit == 'deg'):
half = 180
if half:
unit = 2*half
for i in range(1, len(y)):
diff = y[i] - y[i - 1]
if diff > half: # Jump from -half to half
y[i] = (y[i] - unit)
elif diff < -half: # Jump from half to -half
y[i] = (y[i] + unit)
return x, y
def bode_phase_plot(system, initial_exp=-5, final_exp=5,
color='b', show_axes=False, grid=True, show=True, freq_unit='rad/sec', phase_unit='rad', phase_unwrap=True, **kwargs):
r"""
Returns the Bode phase plot of a continuous-time system.
See ``bode_plot`` for all the parameters.
"""
x, y = bode_phase_numerical_data(system, initial_exp=initial_exp,
final_exp=final_exp, freq_unit=freq_unit, phase_unit=phase_unit, phase_unwrap=phase_unwrap)
plt.plot(x, y, color=color, **kwargs)
plt.xscale('log')
plt.xlabel('Frequency (%s) [Log Scale]' % freq_unit)
plt.ylabel('Phase (%s)' % phase_unit)
plt.title(f'Bode Plot (Phase) of ${latex(system)}$', pad=20)
if grid:
plt.grid(True)
if show_axes:
plt.axhline(0, color='black')
plt.axvline(0, color='black')
if show:
plt.show()
return
return plt
def bode_plot(system, initial_exp=-5, final_exp=5,
grid=True, show_axes=False, show=True, freq_unit='rad/sec', phase_unit='rad', phase_unwrap=True, **kwargs):
r"""
Returns the Bode phase and magnitude plots of a continuous-time system.
Parameters
==========
system : SISOLinearTimeInvariant type
The LTI SISO system for which the Bode Plot is to be computed.
initial_exp : Number, optional
The initial exponent of 10 of the semilog plot. Defaults to -5.
final_exp : Number, optional
The final exponent of 10 of the semilog plot. Defaults to 5.
show : boolean, optional
If ``True``, the plot will be displayed otherwise
the equivalent matplotlib ``plot`` object will be returned.
Defaults to True.
prec : int, optional
The decimal point precision for the point coordinate values.
Defaults to 8.
grid : boolean, optional
If ``True``, the plot will have a grid. Defaults to True.
show_axes : boolean, optional
If ``True``, the coordinate axes will be shown. Defaults to False.
freq_unit : string, optional
User can choose between ``'rad/sec'`` (radians/second) and ``'Hz'`` (Hertz) as frequency units.
phase_unit : string, optional
User can choose between ``'rad'`` (radians) and ``'deg'`` (degree) as phase units.
Examples
========
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy.abc import s
>>> from sympy.physics.control.lti import TransferFunction
>>> from sympy.physics.control.control_plots import bode_plot
>>> tf1 = TransferFunction(1*s**2 + 0.1*s + 7.5, 1*s**4 + 0.12*s**3 + 9*s**2, s)
>>> bode_plot(tf1, initial_exp=0.2, final_exp=0.7) # doctest: +SKIP
See Also
========
bode_magnitude_plot, bode_phase_plot
"""
plt.subplot(211)
mag = bode_magnitude_plot(system, initial_exp=initial_exp, final_exp=final_exp,
show=False, grid=grid, show_axes=show_axes,
freq_unit=freq_unit, **kwargs)
mag.title(f'Bode Plot of ${latex(system)}$', pad=20)
mag.xlabel(None)
plt.subplot(212)
bode_phase_plot(system, initial_exp=initial_exp, final_exp=final_exp,
show=False, grid=grid, show_axes=show_axes, freq_unit=freq_unit, phase_unit=phase_unit, phase_unwrap=phase_unwrap, **kwargs).title(None)
if show:
plt.show()
return
return plt
PK ]ZZZ�c`nR nR sympy/physics/control/lti.pyfrom typing import Type
from sympy import Interval, numer, Rational, solveset
from sympy.core.add import Add
from sympy.core.basic import Basic
from sympy.core.containers import Tuple
from sympy.core.evalf import EvalfMixin
from sympy.core.expr import Expr
from sympy.core.function import expand
from sympy.core.logic import fuzzy_and
from sympy.core.mul import Mul
from sympy.core.numbers import I, pi, oo
from sympy.core.power import Pow
from sympy.core.singleton import S
from sympy.core.symbol import Dummy, Symbol
from sympy.functions import Abs
from sympy.core.sympify import sympify, _sympify
from sympy.matrices import Matrix, ImmutableMatrix, ImmutableDenseMatrix, eye, ShapeError, zeros
from sympy.functions.elementary.exponential import (exp, log)
from sympy.matrices.expressions import MatMul, MatAdd
from sympy.polys import Poly, rootof
from sympy.polys.polyroots import roots
from sympy.polys.polytools import (cancel, degree)
from sympy.series import limit
from sympy.utilities.misc import filldedent
from mpmath.libmp.libmpf import prec_to_dps
__all__ = ['TransferFunction', 'Series', 'MIMOSeries', 'Parallel', 'MIMOParallel',
'Feedback', 'MIMOFeedback', 'TransferFunctionMatrix', 'StateSpace', 'gbt', 'bilinear', 'forward_diff', 'backward_diff',
'phase_margin', 'gain_margin']
def _roots(poly, var):
""" like roots, but works on higher-order polynomials. """
r = roots(poly, var, multiple=True)
n = degree(poly)
if len(r) != n:
r = [rootof(poly, var, k) for k in range(n)]
return r
def gbt(tf, sample_per, alpha):
r"""
Returns falling coefficients of H(z) from numerator and denominator.
Explanation
===========
Where H(z) is the corresponding discretized transfer function,
discretized with the generalised bilinear transformation method.
H(z) is obtained from the continuous transfer function H(s)
by substituting $s(z) = \frac{z-1}{T(\alpha z + (1-\alpha))}$ into H(s), where T is the
sample period.
Coefficients are falling, i.e. $H(z) = \frac{az+b}{cz+d}$ is returned
as [a, b], [c, d].
Examples
========
>>> from sympy.physics.control.lti import TransferFunction, gbt
>>> from sympy.abc import s, L, R, T
>>> tf = TransferFunction(1, s*L + R, s)
>>> numZ, denZ = gbt(tf, T, 0.5)
>>> numZ
[T/(2*(L + R*T/2)), T/(2*(L + R*T/2))]
>>> denZ
[1, (-L + R*T/2)/(L + R*T/2)]
>>> numZ, denZ = gbt(tf, T, 0)
>>> numZ
[T/L]
>>> denZ
[1, (-L + R*T)/L]
>>> numZ, denZ = gbt(tf, T, 1)
>>> numZ
[T/(L + R*T), 0]
>>> denZ
[1, -L/(L + R*T)]
>>> numZ, denZ = gbt(tf, T, 0.3)
>>> numZ
[3*T/(10*(L + 3*R*T/10)), 7*T/(10*(L + 3*R*T/10))]
>>> denZ
[1, (-L + 7*R*T/10)/(L + 3*R*T/10)]
References
==========
.. [1] https://www.polyu.edu.hk/ama/profile/gfzhang/Research/ZCC09_IJC.pdf
"""
if not tf.is_SISO:
raise NotImplementedError("Not implemented for MIMO systems.")
T = sample_per # and sample period T
s = tf.var
z = s # dummy discrete variable z
np = tf.num.as_poly(s).all_coeffs()
dp = tf.den.as_poly(s).all_coeffs()
alpha = Rational(alpha).limit_denominator(1000)
# The next line results from multiplying H(z) with z^N/z^N
N = max(len(np), len(dp)) - 1
num = Add(*[ T**(N-i) * c * (z-1)**i * (alpha * z + 1 - alpha)**(N-i) for c, i in zip(np[::-1], range(len(np))) ])
den = Add(*[ T**(N-i) * c * (z-1)**i * (alpha * z + 1 - alpha)**(N-i) for c, i in zip(dp[::-1], range(len(dp))) ])
num_coefs = num.as_poly(z).all_coeffs()
den_coefs = den.as_poly(z).all_coeffs()
para = den_coefs[0]
num_coefs = [coef/para for coef in num_coefs]
den_coefs = [coef/para for coef in den_coefs]
return num_coefs, den_coefs
def bilinear(tf, sample_per):
r"""
Returns falling coefficients of H(z) from numerator and denominator.
Explanation
===========
Where H(z) is the corresponding discretized transfer function,
discretized with the bilinear transform method.
H(z) is obtained from the continuous transfer function H(s)
by substituting $s(z) = \frac{2}{T}\frac{z-1}{z+1}$ into H(s), where T is the
sample period.
Coefficients are falling, i.e. $H(z) = \frac{az+b}{cz+d}$ is returned
as [a, b], [c, d].
Examples
========
>>> from sympy.physics.control.lti import TransferFunction, bilinear
>>> from sympy.abc import s, L, R, T
>>> tf = TransferFunction(1, s*L + R, s)
>>> numZ, denZ = bilinear(tf, T)
>>> numZ
[T/(2*(L + R*T/2)), T/(2*(L + R*T/2))]
>>> denZ
[1, (-L + R*T/2)/(L + R*T/2)]
"""
return gbt(tf, sample_per, S.Half)
def forward_diff(tf, sample_per):
r"""
Returns falling coefficients of H(z) from numerator and denominator.
Explanation
===========
Where H(z) is the corresponding discretized transfer function,
discretized with the forward difference transform method.
H(z) is obtained from the continuous transfer function H(s)
by substituting $s(z) = \frac{z-1}{T}$ into H(s), where T is the
sample period.
Coefficients are falling, i.e. $H(z) = \frac{az+b}{cz+d}$ is returned
as [a, b], [c, d].
Examples
========
>>> from sympy.physics.control.lti import TransferFunction, forward_diff
>>> from sympy.abc import s, L, R, T
>>> tf = TransferFunction(1, s*L + R, s)
>>> numZ, denZ = forward_diff(tf, T)
>>> numZ
[T/L]
>>> denZ
[1, (-L + R*T)/L]
"""
return gbt(tf, sample_per, S.Zero)
def backward_diff(tf, sample_per):
r"""
Returns falling coefficients of H(z) from numerator and denominator.
Explanation
===========
Where H(z) is the corresponding discretized transfer function,
discretized with the backward difference transform method.
H(z) is obtained from the continuous transfer function H(s)
by substituting $s(z) = \frac{z-1}{Tz}$ into H(s), where T is the
sample period.
Coefficients are falling, i.e. $H(z) = \frac{az+b}{cz+d}$ is returned
as [a, b], [c, d].
Examples
========
>>> from sympy.physics.control.lti import TransferFunction, backward_diff
>>> from sympy.abc import s, L, R, T
>>> tf = TransferFunction(1, s*L + R, s)
>>> numZ, denZ = backward_diff(tf, T)
>>> numZ
[T/(L + R*T), 0]
>>> denZ
[1, -L/(L + R*T)]
"""
return gbt(tf, sample_per, S.One)
def phase_margin(system):
r"""
Returns the phase margin of a continuous time system.
Only applicable to Transfer Functions which can generate valid bode plots.
Raises
======
NotImplementedError
When time delay terms are present in the system.
ValueError
When a SISO LTI system is not passed.
When more than one free symbol is present in the system.
The only variable in the transfer function should be
the variable of the Laplace transform.
Examples
========
>>> from sympy.physics.control import TransferFunction, phase_margin
>>> from sympy.abc import s
>>> tf = TransferFunction(1, s**3 + 2*s**2 + s, s)
>>> phase_margin(tf)
180*(-pi + atan((-1 + (-2*18**(1/3)/(9 + sqrt(93))**(1/3) + 12**(1/3)*(9 + sqrt(93))**(1/3))**2/36)/(-12**(1/3)*(9 + sqrt(93))**(1/3)/3 + 2*18**(1/3)/(3*(9 + sqrt(93))**(1/3)))))/pi + 180
>>> phase_margin(tf).n()
21.3863897518751
>>> tf1 = TransferFunction(s**3, s**2 + 5*s, s)
>>> phase_margin(tf1)
-180 + 180*(atan(sqrt(2)*(-51/10 - sqrt(101)/10)*sqrt(1 + sqrt(101))/(2*(sqrt(101)/2 + 51/2))) + pi)/pi
>>> phase_margin(tf1).n()
-25.1783920627277
>>> tf2 = TransferFunction(1, s + 1, s)
>>> phase_margin(tf2)
-180
See Also
========
gain_margin
References
==========
.. [1] https://en.wikipedia.org/wiki/Phase_margin
"""
from sympy.functions import arg
if not isinstance(system, SISOLinearTimeInvariant):
raise ValueError("Margins are only applicable for SISO LTI systems.")
_w = Dummy("w", real=True)
repl = I*_w
expr = system.to_expr()
len_free_symbols = len(expr.free_symbols)
if expr.has(exp):
raise NotImplementedError("Margins for systems with Time delay terms are not supported.")
elif len_free_symbols > 1:
raise ValueError("Extra degree of freedom found. Make sure"
" that there are no free symbols in the dynamical system other"
" than the variable of Laplace transform.")
w_expr = expr.subs({system.var: repl})
mag = 20*log(Abs(w_expr), 10)
mag_sol = list(solveset(mag, _w, Interval(0, oo, left_open=True)))
if (len(mag_sol) == 0):
pm = S(-180)
else:
wcp = mag_sol[0]
pm = ((arg(w_expr)*S(180)/pi).subs({_w:wcp}) + S(180)) % 360
if(pm >= 180):
pm = pm - 360
return pm
def gain_margin(system):
r"""
Returns the gain margin of a continuous time system.
Only applicable to Transfer Functions which can generate valid bode plots.
Raises
======
NotImplementedError
When time delay terms are present in the system.
ValueError
When a SISO LTI system is not passed.
When more than one free symbol is present in the system.
The only variable in the transfer function should be
the variable of the Laplace transform.
Examples
========
>>> from sympy.physics.control import TransferFunction, gain_margin
>>> from sympy.abc import s
>>> tf = TransferFunction(1, s**3 + 2*s**2 + s, s)
>>> gain_margin(tf)
20*log(2)/log(10)
>>> gain_margin(tf).n()
6.02059991327962
>>> tf1 = TransferFunction(s**3, s**2 + 5*s, s)
>>> gain_margin(tf1)
oo
See Also
========
phase_margin
References
==========
https://en.wikipedia.org/wiki/Bode_plot
"""
if not isinstance(system, SISOLinearTimeInvariant):
raise ValueError("Margins are only applicable for SISO LTI systems.")
_w = Dummy("w", real=True)
repl = I*_w
expr = system.to_expr()
len_free_symbols = len(expr.free_symbols)
if expr.has(exp):
raise NotImplementedError("Margins for systems with Time delay terms are not supported.")
elif len_free_symbols > 1:
raise ValueError("Extra degree of freedom found. Make sure"
" that there are no free symbols in the dynamical system other"
" than the variable of Laplace transform.")
w_expr = expr.subs({system.var: repl})
mag = 20*log(Abs(w_expr), 10)
phase = w_expr
phase_sol = list(solveset(numer(phase.as_real_imag()[1].cancel()),_w, Interval(0, oo, left_open = True)))
if (len(phase_sol) == 0):
gm = oo
else:
wcg = phase_sol[0]
gm = -mag.subs({_w:wcg})
return gm
class LinearTimeInvariant(Basic, EvalfMixin):
"""A common class for all the Linear Time-Invariant Dynamical Systems."""
_clstype: Type
# Users should not directly interact with this class.
def __new__(cls, *system, **kwargs):
if cls is LinearTimeInvariant:
raise NotImplementedError('The LTICommon class is not meant to be used directly.')
return super(LinearTimeInvariant, cls).__new__(cls, *system, **kwargs)
@classmethod
def _check_args(cls, args):
if not args:
raise ValueError("At least 1 argument must be passed.")
if not all(isinstance(arg, cls._clstype) for arg in args):
raise TypeError(f"All arguments must be of type {cls._clstype}.")
var_set = {arg.var for arg in args}
if len(var_set) != 1:
raise ValueError(filldedent(f"""
All transfer functions should use the same complex variable
of the Laplace transform. {len(var_set)} different
values found."""))
@property
def is_SISO(self):
"""Returns `True` if the passed LTI system is SISO else returns False."""
return self._is_SISO
class SISOLinearTimeInvariant(LinearTimeInvariant):
"""A common class for all the SISO Linear Time-Invariant Dynamical Systems."""
# Users should not directly interact with this class.
_is_SISO = True
class MIMOLinearTimeInvariant(LinearTimeInvariant):
"""A common class for all the MIMO Linear Time-Invariant Dynamical Systems."""
# Users should not directly interact with this class.
_is_SISO = False
SISOLinearTimeInvariant._clstype = SISOLinearTimeInvariant
MIMOLinearTimeInvariant._clstype = MIMOLinearTimeInvariant
def _check_other_SISO(func):
def wrapper(*args, **kwargs):
if not isinstance(args[-1], SISOLinearTimeInvariant):
return NotImplemented
else:
return func(*args, **kwargs)
return wrapper
def _check_other_MIMO(func):
def wrapper(*args, **kwargs):
if not isinstance(args[-1], MIMOLinearTimeInvariant):
return NotImplemented
else:
return func(*args, **kwargs)
return wrapper
class TransferFunction(SISOLinearTimeInvariant):
r"""
A class for representing LTI (Linear, time-invariant) systems that can be strictly described
by ratio of polynomials in the Laplace transform complex variable. The arguments
are ``num``, ``den``, and ``var``, where ``num`` and ``den`` are numerator and
denominator polynomials of the ``TransferFunction`` respectively, and the third argument is
a complex variable of the Laplace transform used by these polynomials of the transfer function.
``num`` and ``den`` can be either polynomials or numbers, whereas ``var``
has to be a :py:class:`~.Symbol`.
Explanation
===========
Generally, a dynamical system representing a physical model can be described in terms of Linear
Ordinary Differential Equations like -
$\small{b_{m}y^{\left(m\right)}+b_{m-1}y^{\left(m-1\right)}+\dots+b_{1}y^{\left(1\right)}+b_{0}y=
a_{n}x^{\left(n\right)}+a_{n-1}x^{\left(n-1\right)}+\dots+a_{1}x^{\left(1\right)}+a_{0}x}$
Here, $x$ is the input signal and $y$ is the output signal and superscript on both is the order of derivative
(not exponent). Derivative is taken with respect to the independent variable, $t$. Also, generally $m$ is greater
than $n$.
It is not feasible to analyse the properties of such systems in their native form therefore, we use
mathematical tools like Laplace transform to get a better perspective. Taking the Laplace transform
of both the sides in the equation (at zero initial conditions), we get -
$\small{\mathcal{L}[b_{m}y^{\left(m\right)}+b_{m-1}y^{\left(m-1\right)}+\dots+b_{1}y^{\left(1\right)}+b_{0}y]=
\mathcal{L}[a_{n}x^{\left(n\right)}+a_{n-1}x^{\left(n-1\right)}+\dots+a_{1}x^{\left(1\right)}+a_{0}x]}$
Using the linearity property of Laplace transform and also considering zero initial conditions
(i.e. $\small{y(0^{-}) = 0}$, $\small{y'(0^{-}) = 0}$ and so on), the equation
above gets translated to -
$\small{b_{m}\mathcal{L}[y^{\left(m\right)}]+\dots+b_{1}\mathcal{L}[y^{\left(1\right)}]+b_{0}\mathcal{L}[y]=
a_{n}\mathcal{L}[x^{\left(n\right)}]+\dots+a_{1}\mathcal{L}[x^{\left(1\right)}]+a_{0}\mathcal{L}[x]}$
Now, applying Derivative property of Laplace transform,
$\small{b_{m}s^{m}\mathcal{L}[y]+\dots+b_{1}s\mathcal{L}[y]+b_{0}\mathcal{L}[y]=
a_{n}s^{n}\mathcal{L}[x]+\dots+a_{1}s\mathcal{L}[x]+a_{0}\mathcal{L}[x]}$
Here, the superscript on $s$ is **exponent**. Note that the zero initial conditions assumption, mentioned above, is very important
and cannot be ignored otherwise the dynamical system cannot be considered time-independent and the simplified equation above
cannot be reached.
Collecting $\mathcal{L}[y]$ and $\mathcal{L}[x]$ terms from both the sides and taking the ratio
$\frac{ \mathcal{L}\left\{y\right\} }{ \mathcal{L}\left\{x\right\} }$, we get the typical rational form of transfer
function.
The numerator of the transfer function is, therefore, the Laplace transform of the output signal
(The signals are represented as functions of time) and similarly, the denominator
of the transfer function is the Laplace transform of the input signal. It is also a convention
to denote the input and output signal's Laplace transform with capital alphabets like shown below.
$H(s) = \frac{Y(s)}{X(s)} = \frac{ \mathcal{L}\left\{y(t)\right\} }{ \mathcal{L}\left\{x(t)\right\} }$
$s$, also known as complex frequency, is a complex variable in the Laplace domain. It corresponds to the
equivalent variable $t$, in the time domain. Transfer functions are sometimes also referred to as the Laplace
transform of the system's impulse response. Transfer function, $H$, is represented as a rational
function in $s$ like,
$H(s) =\ \frac{a_{n}s^{n}+a_{n-1}s^{n-1}+\dots+a_{1}s+a_{0}}{b_{m}s^{m}+b_{m-1}s^{m-1}+\dots+b_{1}s+b_{0}}$
Parameters
==========
num : Expr, Number
The numerator polynomial of the transfer function.
den : Expr, Number
The denominator polynomial of the transfer function.
var : Symbol
Complex variable of the Laplace transform used by the
polynomials of the transfer function.
Raises
======
TypeError
When ``var`` is not a Symbol or when ``num`` or ``den`` is not a
number or a polynomial.
ValueError
When ``den`` is zero.
Examples
========
>>> from sympy.abc import s, p, a
>>> from sympy.physics.control.lti import TransferFunction
>>> tf1 = TransferFunction(s + a, s**2 + s + 1, s)
>>> tf1
TransferFunction(a + s, s**2 + s + 1, s)
>>> tf1.num
a + s
>>> tf1.den
s**2 + s + 1
>>> tf1.var
s
>>> tf1.args
(a + s, s**2 + s + 1, s)
Any complex variable can be used for ``var``.
>>> tf2 = TransferFunction(a*p**3 - a*p**2 + s*p, p + a**2, p)
>>> tf2
TransferFunction(a*p**3 - a*p**2 + p*s, a**2 + p, p)
>>> tf3 = TransferFunction((p + 3)*(p - 1), (p - 1)*(p + 5), p)
>>> tf3
TransferFunction((p - 1)*(p + 3), (p - 1)*(p + 5), p)
To negate a transfer function the ``-`` operator can be prepended:
>>> tf4 = TransferFunction(-a + s, p**2 + s, p)
>>> -tf4
TransferFunction(a - s, p**2 + s, p)
>>> tf5 = TransferFunction(s**4 - 2*s**3 + 5*s + 4, s + 4, s)
>>> -tf5
TransferFunction(-s**4 + 2*s**3 - 5*s - 4, s + 4, s)
You can use a float or an integer (or other constants) as numerator and denominator:
>>> tf6 = TransferFunction(1/2, 4, s)
>>> tf6.num
0.500000000000000
>>> tf6.den
4
>>> tf6.var
s
>>> tf6.args
(0.5, 4, s)
You can take the integer power of a transfer function using the ``**`` operator:
>>> tf7 = TransferFunction(s + a, s - a, s)
>>> tf7**3
TransferFunction((a + s)**3, (-a + s)**3, s)
>>> tf7**0
TransferFunction(1, 1, s)
>>> tf8 = TransferFunction(p + 4, p - 3, p)
>>> tf8**-1
TransferFunction(p - 3, p + 4, p)
Addition, subtraction, and multiplication of transfer functions can form
unevaluated ``Series`` or ``Parallel`` objects.
>>> tf9 = TransferFunction(s + 1, s**2 + s + 1, s)
>>> tf10 = TransferFunction(s - p, s + 3, s)
>>> tf11 = TransferFunction(4*s**2 + 2*s - 4, s - 1, s)
>>> tf12 = TransferFunction(1 - s, s**2 + 4, s)
>>> tf9 + tf10
Parallel(TransferFunction(s + 1, s**2 + s + 1, s), TransferFunction(-p + s, s + 3, s))
>>> tf10 - tf11
Parallel(TransferFunction(-p + s, s + 3, s), TransferFunction(-4*s**2 - 2*s + 4, s - 1, s))
>>> tf9 * tf10
Series(TransferFunction(s + 1, s**2 + s + 1, s), TransferFunction(-p + s, s + 3, s))
>>> tf10 - (tf9 + tf12)
Parallel(TransferFunction(-p + s, s + 3, s), TransferFunction(-s - 1, s**2 + s + 1, s), TransferFunction(s - 1, s**2 + 4, s))
>>> tf10 - (tf9 * tf12)
Parallel(TransferFunction(-p + s, s + 3, s), Series(TransferFunction(-1, 1, s), TransferFunction(s + 1, s**2 + s + 1, s), TransferFunction(1 - s, s**2 + 4, s)))
>>> tf11 * tf10 * tf9
Series(TransferFunction(4*s**2 + 2*s - 4, s - 1, s), TransferFunction(-p + s, s + 3, s), TransferFunction(s + 1, s**2 + s + 1, s))
>>> tf9 * tf11 + tf10 * tf12
Parallel(Series(TransferFunction(s + 1, s**2 + s + 1, s), TransferFunction(4*s**2 + 2*s - 4, s - 1, s)), Series(TransferFunction(-p + s, s + 3, s), TransferFunction(1 - s, s**2 + 4, s)))
>>> (tf9 + tf12) * (tf10 + tf11)
Series(Parallel(TransferFunction(s + 1, s**2 + s + 1, s), TransferFunction(1 - s, s**2 + 4, s)), Parallel(TransferFunction(-p + s, s + 3, s), TransferFunction(4*s**2 + 2*s - 4, s - 1, s)))
These unevaluated ``Series`` or ``Parallel`` objects can convert into the
resultant transfer function using ``.doit()`` method or by ``.rewrite(TransferFunction)``.
>>> ((tf9 + tf10) * tf12).doit()
TransferFunction((1 - s)*((-p + s)*(s**2 + s + 1) + (s + 1)*(s + 3)), (s + 3)*(s**2 + 4)*(s**2 + s + 1), s)
>>> (tf9 * tf10 - tf11 * tf12).rewrite(TransferFunction)
TransferFunction(-(1 - s)*(s + 3)*(s**2 + s + 1)*(4*s**2 + 2*s - 4) + (-p + s)*(s - 1)*(s + 1)*(s**2 + 4), (s - 1)*(s + 3)*(s**2 + 4)*(s**2 + s + 1), s)
See Also
========
Feedback, Series, Parallel
References
==========
.. [1] https://en.wikipedia.org/wiki/Transfer_function
.. [2] https://en.wikipedia.org/wiki/Laplace_transform
"""
def __new__(cls, num, den, var):
num, den = _sympify(num), _sympify(den)
if not isinstance(var, Symbol):
raise TypeError("Variable input must be a Symbol.")
if den == 0:
raise ValueError("TransferFunction cannot have a zero denominator.")
if (((isinstance(num, (Expr, TransferFunction, Series, Parallel)) and num.has(Symbol)) or num.is_number) and
((isinstance(den, (Expr, TransferFunction, Series, Parallel)) and den.has(Symbol)) or den.is_number)):
return super(TransferFunction, cls).__new__(cls, num, den, var)
else:
raise TypeError("Unsupported type for numerator or denominator of TransferFunction.")
@classmethod
def from_rational_expression(cls, expr, var=None):
r"""
Creates a new ``TransferFunction`` efficiently from a rational expression.
Parameters
==========
expr : Expr, Number
The rational expression representing the ``TransferFunction``.
var : Symbol, optional
Complex variable of the Laplace transform used by the
polynomials of the transfer function.
Raises
======
ValueError
When ``expr`` is of type ``Number`` and optional parameter ``var``
is not passed.
When ``expr`` has more than one variables and an optional parameter
``var`` is not passed.
ZeroDivisionError
When denominator of ``expr`` is zero or it has ``ComplexInfinity``
in its numerator.
Examples
========
>>> from sympy.abc import s, p, a
>>> from sympy.physics.control.lti import TransferFunction
>>> expr1 = (s + 5)/(3*s**2 + 2*s + 1)
>>> tf1 = TransferFunction.from_rational_expression(expr1)
>>> tf1
TransferFunction(s + 5, 3*s**2 + 2*s + 1, s)
>>> expr2 = (a*p**3 - a*p**2 + s*p)/(p + a**2) # Expr with more than one variables
>>> tf2 = TransferFunction.from_rational_expression(expr2, p)
>>> tf2
TransferFunction(a*p**3 - a*p**2 + p*s, a**2 + p, p)
In case of conflict between two or more variables in a expression, SymPy will
raise a ``ValueError``, if ``var`` is not passed by the user.
>>> tf = TransferFunction.from_rational_expression((a + a*s)/(s**2 + s + 1))
Traceback (most recent call last):
...
ValueError: Conflicting values found for positional argument `var` ({a, s}). Specify it manually.
This can be corrected by specifying the ``var`` parameter manually.
>>> tf = TransferFunction.from_rational_expression((a + a*s)/(s**2 + s + 1), s)
>>> tf
TransferFunction(a*s + a, s**2 + s + 1, s)
``var`` also need to be specified when ``expr`` is a ``Number``
>>> tf3 = TransferFunction.from_rational_expression(10, s)
>>> tf3
TransferFunction(10, 1, s)
"""
expr = _sympify(expr)
if var is None:
_free_symbols = expr.free_symbols
_len_free_symbols = len(_free_symbols)
if _len_free_symbols == 1:
var = list(_free_symbols)[0]
elif _len_free_symbols == 0:
raise ValueError(filldedent("""
Positional argument `var` not found in the
TransferFunction defined. Specify it manually."""))
else:
raise ValueError(filldedent("""
Conflicting values found for positional argument `var` ({}).
Specify it manually.""".format(_free_symbols)))
_num, _den = expr.as_numer_denom()
if _den == 0 or _num.has(S.ComplexInfinity):
raise ZeroDivisionError("TransferFunction cannot have a zero denominator.")
return cls(_num, _den, var)
@classmethod
def from_coeff_lists(cls, num_list, den_list, var):
r"""
Creates a new ``TransferFunction`` efficiently from a list of coefficients.
Parameters
==========
num_list : Sequence
Sequence comprising of numerator coefficients.
den_list : Sequence
Sequence comprising of denominator coefficients.
var : Symbol
Complex variable of the Laplace transform used by the
polynomials of the transfer function.
Raises
======
ZeroDivisionError
When the constructed denominator is zero.
Examples
========
>>> from sympy.abc import s, p
>>> from sympy.physics.control.lti import TransferFunction
>>> num = [1, 0, 2]
>>> den = [3, 2, 2, 1]
>>> tf = TransferFunction.from_coeff_lists(num, den, s)
>>> tf
TransferFunction(s**2 + 2, 3*s**3 + 2*s**2 + 2*s + 1, s)
# Create a Transfer Function with more than one variable
>>> tf1 = TransferFunction.from_coeff_lists([p, 1], [2*p, 0, 4], s)
>>> tf1
TransferFunction(p*s + 1, 2*p*s**2 + 4, s)
"""
num_list = num_list[::-1]
den_list = den_list[::-1]
num_var_powers = [var**i for i in range(len(num_list))]
den_var_powers = [var**i for i in range(len(den_list))]
_num = sum(coeff * var_power for coeff, var_power in zip(num_list, num_var_powers))
_den = sum(coeff * var_power for coeff, var_power in zip(den_list, den_var_powers))
if _den == 0:
raise ZeroDivisionError("TransferFunction cannot have a zero denominator.")
return cls(_num, _den, var)
@classmethod
def from_zpk(cls, zeros, poles, gain, var):
r"""
Creates a new ``TransferFunction`` from given zeros, poles and gain.
Parameters
==========
zeros : Sequence
Sequence comprising of zeros of transfer function.
poles : Sequence
Sequence comprising of poles of transfer function.
gain : Number, Symbol, Expression
A scalar value specifying gain of the model.
var : Symbol
Complex variable of the Laplace transform used by the
polynomials of the transfer function.
Examples
========
>>> from sympy.abc import s, p, k
>>> from sympy.physics.control.lti import TransferFunction
>>> zeros = [1, 2, 3]
>>> poles = [6, 5, 4]
>>> gain = 7
>>> tf = TransferFunction.from_zpk(zeros, poles, gain, s)
>>> tf
TransferFunction(7*(s - 3)*(s - 2)*(s - 1), (s - 6)*(s - 5)*(s - 4), s)
# Create a Transfer Function with variable poles and zeros
>>> tf1 = TransferFunction.from_zpk([p, k], [p + k, p - k], 2, s)
>>> tf1
TransferFunction(2*(-k + s)*(-p + s), (-k - p + s)*(k - p + s), s)
# Complex poles or zeros are acceptable
>>> tf2 = TransferFunction.from_zpk([0], [1-1j, 1+1j, 2], -2, s)
>>> tf2
TransferFunction(-2*s, (s - 2)*(s - 1.0 - 1.0*I)*(s - 1.0 + 1.0*I), s)
"""
num_poly = 1
den_poly = 1
for zero in zeros:
num_poly *= var - zero
for pole in poles:
den_poly *= var - pole
return cls(gain*num_poly, den_poly, var)
@property
def num(self):
"""
Returns the numerator polynomial of the transfer function.
Examples
========
>>> from sympy.abc import s, p
>>> from sympy.physics.control.lti import TransferFunction
>>> G1 = TransferFunction(s**2 + p*s + 3, s - 4, s)
>>> G1.num
p*s + s**2 + 3
>>> G2 = TransferFunction((p + 5)*(p - 3), (p - 3)*(p + 1), p)
>>> G2.num
(p - 3)*(p + 5)
"""
return self.args[0]
@property
def den(self):
"""
Returns the denominator polynomial of the transfer function.
Examples
========
>>> from sympy.abc import s, p
>>> from sympy.physics.control.lti import TransferFunction
>>> G1 = TransferFunction(s + 4, p**3 - 2*p + 4, s)
>>> G1.den
p**3 - 2*p + 4
>>> G2 = TransferFunction(3, 4, s)
>>> G2.den
4
"""
return self.args[1]
@property
def var(self):
"""
Returns the complex variable of the Laplace transform used by the polynomials of
the transfer function.
Examples
========
>>> from sympy.abc import s, p
>>> from sympy.physics.control.lti import TransferFunction
>>> G1 = TransferFunction(p**2 + 2*p + 4, p - 6, p)
>>> G1.var
p
>>> G2 = TransferFunction(0, s - 5, s)
>>> G2.var
s
"""
return self.args[2]
def _eval_subs(self, old, new):
arg_num = self.num.subs(old, new)
arg_den = self.den.subs(old, new)
argnew = TransferFunction(arg_num, arg_den, self.var)
return self if old == self.var else argnew
def _eval_evalf(self, prec):
return TransferFunction(
self.num._eval_evalf(prec),
self.den._eval_evalf(prec),
self.var)
def _eval_simplify(self, **kwargs):
tf = cancel(Mul(self.num, 1/self.den, evaluate=False), expand=False).as_numer_denom()
num_, den_ = tf[0], tf[1]
return TransferFunction(num_, den_, self.var)
def _eval_rewrite_as_StateSpace(self, *args):
"""
Returns the equivalent space space model of the transfer function model.
The state space model will be returned in the controllable cannonical form.
Unlike the space state to transfer function model conversion, the transfer function
to state space model conversion is not unique. There can be multiple state space
representations of a given transfer function model.
Examples
========
>>> from sympy.abc import s
>>> from sympy.physics.control import TransferFunction, StateSpace
>>> tf = TransferFunction(s**2 + 1, s**3 + 2*s + 10, s)
>>> tf.rewrite(StateSpace)
StateSpace(Matrix([
[ 0, 1, 0],
[ 0, 0, 1],
[-10, -2, 0]]), Matrix([
[0],
[0],
[1]]), Matrix([[1, 0, 1]]), Matrix([[0]]))
"""
if not self.is_proper:
raise ValueError("Transfer Function must be proper.")
num_poly = Poly(self.num, self.var)
den_poly = Poly(self.den, self.var)
n = den_poly.degree()
num_coeffs = num_poly.all_coeffs()
den_coeffs = den_poly.all_coeffs()
diff = n - num_poly.degree()
num_coeffs = [0]*diff + num_coeffs
a = den_coeffs[1:]
a_mat = Matrix([[(-1)*coefficient/den_coeffs[0] for coefficient in reversed(a)]])
vert = zeros(n-1, 1)
mat = eye(n-1)
A = vert.row_join(mat)
A = A.col_join(a_mat)
B = zeros(n, 1)
B[n-1] = 1
i = n
C = []
while(i > 0):
C.append(num_coeffs[i] - den_coeffs[i]*num_coeffs[0])
i -= 1
C = Matrix([C])
D = Matrix([num_coeffs[0]])
return StateSpace(A, B, C, D)
def expand(self):
"""
Returns the transfer function with numerator and denominator
in expanded form.
Examples
========
>>> from sympy.abc import s, p, a, b
>>> from sympy.physics.control.lti import TransferFunction
>>> G1 = TransferFunction((a - s)**2, (s**2 + a)**2, s)
>>> G1.expand()
TransferFunction(a**2 - 2*a*s + s**2, a**2 + 2*a*s**2 + s**4, s)
>>> G2 = TransferFunction((p + 3*b)*(p - b), (p - b)*(p + 2*b), p)
>>> G2.expand()
TransferFunction(-3*b**2 + 2*b*p + p**2, -2*b**2 + b*p + p**2, p)
"""
return TransferFunction(expand(self.num), expand(self.den), self.var)
def dc_gain(self):
"""
Computes the gain of the response as the frequency approaches zero.
The DC gain is infinite for systems with pure integrators.
Examples
========
>>> from sympy.abc import s, p, a, b
>>> from sympy.physics.control.lti import TransferFunction
>>> tf1 = TransferFunction(s + 3, s**2 - 9, s)
>>> tf1.dc_gain()
-1/3
>>> tf2 = TransferFunction(p**2, p - 3 + p**3, p)
>>> tf2.dc_gain()
0
>>> tf3 = TransferFunction(a*p**2 - b, s + b, s)
>>> tf3.dc_gain()
(a*p**2 - b)/b
>>> tf4 = TransferFunction(1, s, s)
>>> tf4.dc_gain()
oo
"""
m = Mul(self.num, Pow(self.den, -1, evaluate=False), evaluate=False)
return limit(m, self.var, 0)
def poles(self):
"""
Returns the poles of a transfer function.
Examples
========
>>> from sympy.abc import s, p, a
>>> from sympy.physics.control.lti import TransferFunction
>>> tf1 = TransferFunction((p + 3)*(p - 1), (p - 1)*(p + 5), p)
>>> tf1.poles()
[-5, 1]
>>> tf2 = TransferFunction((1 - s)**2, (s**2 + 1)**2, s)
>>> tf2.poles()
[I, I, -I, -I]
>>> tf3 = TransferFunction(s**2, a*s + p, s)
>>> tf3.poles()
[-p/a]
"""
return _roots(Poly(self.den, self.var), self.var)
def zeros(self):
"""
Returns the zeros of a transfer function.
Examples
========
>>> from sympy.abc import s, p, a
>>> from sympy.physics.control.lti import TransferFunction
>>> tf1 = TransferFunction((p + 3)*(p - 1), (p - 1)*(p + 5), p)
>>> tf1.zeros()
[-3, 1]
>>> tf2 = TransferFunction((1 - s)**2, (s**2 + 1)**2, s)
>>> tf2.zeros()
[1, 1]
>>> tf3 = TransferFunction(s**2, a*s + p, s)
>>> tf3.zeros()
[0, 0]
"""
return _roots(Poly(self.num, self.var), self.var)
def eval_frequency(self, other):
"""
Returns the system response at any point in the real or complex plane.
Examples
========
>>> from sympy.abc import s, p, a
>>> from sympy.physics.control.lti import TransferFunction
>>> from sympy import I
>>> tf1 = TransferFunction(1, s**2 + 2*s + 1, s)
>>> omega = 0.1
>>> tf1.eval_frequency(I*omega)
1/(0.99 + 0.2*I)
>>> tf2 = TransferFunction(s**2, a*s + p, s)
>>> tf2.eval_frequency(2)
4/(2*a + p)
>>> tf2.eval_frequency(I*2)
-4/(2*I*a + p)
"""
arg_num = self.num.subs(self.var, other)
arg_den = self.den.subs(self.var, other)
argnew = TransferFunction(arg_num, arg_den, self.var).to_expr()
return argnew.expand()
def is_stable(self):
"""
Returns True if the transfer function is asymptotically stable; else False.
This would not check the marginal or conditional stability of the system.
Examples
========
>>> from sympy.abc import s, p, a
>>> from sympy import symbols
>>> from sympy.physics.control.lti import TransferFunction
>>> q, r = symbols('q, r', negative=True)
>>> tf1 = TransferFunction((1 - s)**2, (s + 1)**2, s)
>>> tf1.is_stable()
True
>>> tf2 = TransferFunction((1 - p)**2, (s**2 + 1)**2, s)
>>> tf2.is_stable()
False
>>> tf3 = TransferFunction(4, q*s - r, s)
>>> tf3.is_stable()
False
>>> tf4 = TransferFunction(p + 1, a*p - s**2, p)
>>> tf4.is_stable() is None # Not enough info about the symbols to determine stability
True
"""
return fuzzy_and(pole.as_real_imag()[0].is_negative for pole in self.poles())
def __add__(self, other):
if isinstance(other, (TransferFunction, Series)):
if not self.var == other.var:
raise ValueError(filldedent("""
All the transfer functions should use the same complex variable
of the Laplace transform."""))
return Parallel(self, other)
elif isinstance(other, Parallel):
if not self.var == other.var:
raise ValueError(filldedent("""
All the transfer functions should use the same complex variable
of the Laplace transform."""))
arg_list = list(other.args)
return Parallel(self, *arg_list)
else:
raise ValueError("TransferFunction cannot be added with {}.".
format(type(other)))
def __radd__(self, other):
return self + other
def __sub__(self, other):
if isinstance(other, (TransferFunction, Series)):
if not self.var == other.var:
raise ValueError(filldedent("""
All the transfer functions should use the same complex variable
of the Laplace transform."""))
return Parallel(self, -other)
elif isinstance(other, Parallel):
if not self.var == other.var:
raise ValueError(filldedent("""
All the transfer functions should use the same complex variable
of the Laplace transform."""))
arg_list = [-i for i in list(other.args)]
return Parallel(self, *arg_list)
else:
raise ValueError("{} cannot be subtracted from a TransferFunction."
.format(type(other)))
def __rsub__(self, other):
return -self + other
def __mul__(self, other):
if isinstance(other, (TransferFunction, Parallel)):
if not self.var == other.var:
raise ValueError(filldedent("""
All the transfer functions should use the same complex variable
of the Laplace transform."""))
return Series(self, other)
elif isinstance(other, Series):
if not self.var == other.var:
raise ValueError(filldedent("""
All the transfer functions should use the same complex variable
of the Laplace transform."""))
arg_list = list(other.args)
return Series(self, *arg_list)
else:
raise ValueError("TransferFunction cannot be multiplied with {}."
.format(type(other)))
__rmul__ = __mul__
def __truediv__(self, other):
if isinstance(other, TransferFunction):
if not self.var == other.var:
raise ValueError(filldedent("""
All the transfer functions should use the same complex variable
of the Laplace transform."""))
return Series(self, TransferFunction(other.den, other.num, self.var))
elif (isinstance(other, Parallel) and len(other.args
) == 2 and isinstance(other.args[0], TransferFunction)
and isinstance(other.args[1], (Series, TransferFunction))):
if not self.var == other.var:
raise ValueError(filldedent("""
Both TransferFunction and Parallel should use the
same complex variable of the Laplace transform."""))
if other.args[1] == self:
# plant and controller with unit feedback.
return Feedback(self, other.args[0])
other_arg_list = list(other.args[1].args) if isinstance(
other.args[1], Series) else other.args[1]
if other_arg_list == other.args[1]:
return Feedback(self, other_arg_list)
elif self in other_arg_list:
other_arg_list.remove(self)
else:
return Feedback(self, Series(*other_arg_list))
if len(other_arg_list) == 1:
return Feedback(self, *other_arg_list)
else:
return Feedback(self, Series(*other_arg_list))
else:
raise ValueError("TransferFunction cannot be divided by {}.".
format(type(other)))
__rtruediv__ = __truediv__
def __pow__(self, p):
p = sympify(p)
if not p.is_Integer:
raise ValueError("Exponent must be an integer.")
if p is S.Zero:
return TransferFunction(1, 1, self.var)
elif p > 0:
num_, den_ = self.num**p, self.den**p
else:
p = abs(p)
num_, den_ = self.den**p, self.num**p
return TransferFunction(num_, den_, self.var)
def __neg__(self):
return TransferFunction(-self.num, self.den, self.var)
@property
def is_proper(self):
"""
Returns True if degree of the numerator polynomial is less than
or equal to degree of the denominator polynomial, else False.
Examples
========
>>> from sympy.abc import s, p, a, b
>>> from sympy.physics.control.lti import TransferFunction
>>> tf1 = TransferFunction(b*s**2 + p**2 - a*p + s, b - p**2, s)
>>> tf1.is_proper
False
>>> tf2 = TransferFunction(p**2 - 4*p, p**3 + 3*p + 2, p)
>>> tf2.is_proper
True
"""
return degree(self.num, self.var) <= degree(self.den, self.var)
@property
def is_strictly_proper(self):
"""
Returns True if degree of the numerator polynomial is strictly less
than degree of the denominator polynomial, else False.
Examples
========
>>> from sympy.abc import s, p, a, b
>>> from sympy.physics.control.lti import TransferFunction
>>> tf1 = TransferFunction(a*p**2 + b*s, s - p, s)
>>> tf1.is_strictly_proper
False
>>> tf2 = TransferFunction(s**3 - 2, s**4 + 5*s + 6, s)
>>> tf2.is_strictly_proper
True
"""
return degree(self.num, self.var) < degree(self.den, self.var)
@property
def is_biproper(self):
"""
Returns True if degree of the numerator polynomial is equal to
degree of the denominator polynomial, else False.
Examples
========
>>> from sympy.abc import s, p, a, b
>>> from sympy.physics.control.lti import TransferFunction
>>> tf1 = TransferFunction(a*p**2 + b*s, s - p, s)
>>> tf1.is_biproper
True
>>> tf2 = TransferFunction(p**2, p + a, p)
>>> tf2.is_biproper
False
"""
return degree(self.num, self.var) == degree(self.den, self.var)
def to_expr(self):
"""
Converts a ``TransferFunction`` object to SymPy Expr.
Examples
========
>>> from sympy.abc import s, p, a, b
>>> from sympy.physics.control.lti import TransferFunction
>>> from sympy import Expr
>>> tf1 = TransferFunction(s, a*s**2 + 1, s)
>>> tf1.to_expr()
s/(a*s**2 + 1)
>>> isinstance(_, Expr)
True
>>> tf2 = TransferFunction(1, (p + 3*b)*(b - p), p)
>>> tf2.to_expr()
1/((b - p)*(3*b + p))
>>> tf3 = TransferFunction((s - 2)*(s - 3), (s - 1)*(s - 2)*(s - 3), s)
>>> tf3.to_expr()
((s - 3)*(s - 2))/(((s - 3)*(s - 2)*(s - 1)))
"""
if self.num != 1:
return Mul(self.num, Pow(self.den, -1, evaluate=False), evaluate=False)
else:
return Pow(self.den, -1, evaluate=False)
def _flatten_args(args, _cls):
temp_args = []
for arg in args:
if isinstance(arg, _cls):
temp_args.extend(arg.args)
else:
temp_args.append(arg)
return tuple(temp_args)
def _dummify_args(_arg, var):
dummy_dict = {}
dummy_arg_list = []
for arg in _arg:
_s = Dummy()
dummy_dict[_s] = var
dummy_arg = arg.subs({var: _s})
dummy_arg_list.append(dummy_arg)
return dummy_arg_list, dummy_dict
class Series(SISOLinearTimeInvariant):
r"""
A class for representing a series configuration of SISO systems.
Parameters
==========
args : SISOLinearTimeInvariant
SISO systems in a series configuration.
evaluate : Boolean, Keyword
When passed ``True``, returns the equivalent
``Series(*args).doit()``. Set to ``False`` by default.
Raises
======
ValueError
When no argument is passed.
``var`` attribute is not same for every system.
TypeError
Any of the passed ``*args`` has unsupported type
A combination of SISO and MIMO systems is
passed. There should be homogeneity in the
type of systems passed, SISO in this case.
Examples
========
>>> from sympy.abc import s, p, a, b
>>> from sympy.physics.control.lti import TransferFunction, Series, Parallel
>>> tf1 = TransferFunction(a*p**2 + b*s, s - p, s)
>>> tf2 = TransferFunction(s**3 - 2, s**4 + 5*s + 6, s)
>>> tf3 = TransferFunction(p**2, p + s, s)
>>> S1 = Series(tf1, tf2)
>>> S1
Series(TransferFunction(a*p**2 + b*s, -p + s, s), TransferFunction(s**3 - 2, s**4 + 5*s + 6, s))
>>> S1.var
s
>>> S2 = Series(tf2, Parallel(tf3, -tf1))
>>> S2
Series(TransferFunction(s**3 - 2, s**4 + 5*s + 6, s), Parallel(TransferFunction(p**2, p + s, s), TransferFunction(-a*p**2 - b*s, -p + s, s)))
>>> S2.var
s
>>> S3 = Series(Parallel(tf1, tf2), Parallel(tf2, tf3))
>>> S3
Series(Parallel(TransferFunction(a*p**2 + b*s, -p + s, s), TransferFunction(s**3 - 2, s**4 + 5*s + 6, s)), Parallel(TransferFunction(s**3 - 2, s**4 + 5*s + 6, s), TransferFunction(p**2, p + s, s)))
>>> S3.var
s
You can get the resultant transfer function by using ``.doit()`` method:
>>> S3 = Series(tf1, tf2, -tf3)
>>> S3.doit()
TransferFunction(-p**2*(s**3 - 2)*(a*p**2 + b*s), (-p + s)*(p + s)*(s**4 + 5*s + 6), s)
>>> S4 = Series(tf2, Parallel(tf1, -tf3))
>>> S4.doit()
TransferFunction((s**3 - 2)*(-p**2*(-p + s) + (p + s)*(a*p**2 + b*s)), (-p + s)*(p + s)*(s**4 + 5*s + 6), s)
Notes
=====
All the transfer functions should use the same complex variable
``var`` of the Laplace transform.
See Also
========
MIMOSeries, Parallel, TransferFunction, Feedback
"""
def __new__(cls, *args, evaluate=False):
args = _flatten_args(args, Series)
cls._check_args(args)
obj = super().__new__(cls, *args)
return obj.doit() if evaluate else obj
@property
def var(self):
"""
Returns the complex variable used by all the transfer functions.
Examples
========
>>> from sympy.abc import p
>>> from sympy.physics.control.lti import TransferFunction, Series, Parallel
>>> G1 = TransferFunction(p**2 + 2*p + 4, p - 6, p)
>>> G2 = TransferFunction(p, 4 - p, p)
>>> G3 = TransferFunction(0, p**4 - 1, p)
>>> Series(G1, G2).var
p
>>> Series(-G3, Parallel(G1, G2)).var
p
"""
return self.args[0].var
def doit(self, **hints):
"""
Returns the resultant transfer function obtained after evaluating
the transfer functions in series configuration.
Examples
========
>>> from sympy.abc import s, p, a, b
>>> from sympy.physics.control.lti import TransferFunction, Series
>>> tf1 = TransferFunction(a*p**2 + b*s, s - p, s)
>>> tf2 = TransferFunction(s**3 - 2, s**4 + 5*s + 6, s)
>>> Series(tf2, tf1).doit()
TransferFunction((s**3 - 2)*(a*p**2 + b*s), (-p + s)*(s**4 + 5*s + 6), s)
>>> Series(-tf1, -tf2).doit()
TransferFunction((2 - s**3)*(-a*p**2 - b*s), (-p + s)*(s**4 + 5*s + 6), s)
"""
_num_arg = (arg.doit().num for arg in self.args)
_den_arg = (arg.doit().den for arg in self.args)
res_num = Mul(*_num_arg, evaluate=True)
res_den = Mul(*_den_arg, evaluate=True)
return TransferFunction(res_num, res_den, self.var)
def _eval_rewrite_as_TransferFunction(self, *args, **kwargs):
return self.doit()
@_check_other_SISO
def __add__(self, other):
if isinstance(other, Parallel):
arg_list = list(other.args)
return Parallel(self, *arg_list)
return Parallel(self, other)
__radd__ = __add__
@_check_other_SISO
def __sub__(self, other):
return self + (-other)
def __rsub__(self, other):
return -self + other
@_check_other_SISO
def __mul__(self, other):
arg_list = list(self.args)
return Series(*arg_list, other)
def __truediv__(self, other):
if isinstance(other, TransferFunction):
return Series(*self.args, TransferFunction(other.den, other.num, other.var))
elif isinstance(other, Series):
tf_self = self.rewrite(TransferFunction)
tf_other = other.rewrite(TransferFunction)
return tf_self / tf_other
elif (isinstance(other, Parallel) and len(other.args) == 2
and isinstance(other.args[0], TransferFunction) and isinstance(other.args[1], Series)):
if not self.var == other.var:
raise ValueError(filldedent("""
All the transfer functions should use the same complex variable
of the Laplace transform."""))
self_arg_list = set(self.args)
other_arg_list = set(other.args[1].args)
res = list(self_arg_list ^ other_arg_list)
if len(res) == 0:
return Feedback(self, other.args[0])
elif len(res) == 1:
return Feedback(self, *res)
else:
return Feedback(self, Series(*res))
else:
raise ValueError("This transfer function expression is invalid.")
def __neg__(self):
return Series(TransferFunction(-1, 1, self.var), self)
def to_expr(self):
"""Returns the equivalent ``Expr`` object."""
return Mul(*(arg.to_expr() for arg in self.args), evaluate=False)
@property
def is_proper(self):
"""
Returns True if degree of the numerator polynomial of the resultant transfer
function is less than or equal to degree of the denominator polynomial of
the same, else False.
Examples
========
>>> from sympy.abc import s, p, a, b
>>> from sympy.physics.control.lti import TransferFunction, Series
>>> tf1 = TransferFunction(b*s**2 + p**2 - a*p + s, b - p**2, s)
>>> tf2 = TransferFunction(p**2 - 4*p, p**3 + 3*s + 2, s)
>>> tf3 = TransferFunction(s, s**2 + s + 1, s)
>>> S1 = Series(-tf2, tf1)
>>> S1.is_proper
False
>>> S2 = Series(tf1, tf2, tf3)
>>> S2.is_proper
True
"""
return self.doit().is_proper
@property
def is_strictly_proper(self):
"""
Returns True if degree of the numerator polynomial of the resultant transfer
function is strictly less than degree of the denominator polynomial of
the same, else False.
Examples
========
>>> from sympy.abc import s, p, a, b
>>> from sympy.physics.control.lti import TransferFunction, Series
>>> tf1 = TransferFunction(a*p**2 + b*s, s - p, s)
>>> tf2 = TransferFunction(s**3 - 2, s**2 + 5*s + 6, s)
>>> tf3 = TransferFunction(1, s**2 + s + 1, s)
>>> S1 = Series(tf1, tf2)
>>> S1.is_strictly_proper
False
>>> S2 = Series(tf1, tf2, tf3)
>>> S2.is_strictly_proper
True
"""
return self.doit().is_strictly_proper
@property
def is_biproper(self):
r"""
Returns True if degree of the numerator polynomial of the resultant transfer
function is equal to degree of the denominator polynomial of
the same, else False.
Examples
========
>>> from sympy.abc import s, p, a, b
>>> from sympy.physics.control.lti import TransferFunction, Series
>>> tf1 = TransferFunction(a*p**2 + b*s, s - p, s)
>>> tf2 = TransferFunction(p, s**2, s)
>>> tf3 = TransferFunction(s**2, 1, s)
>>> S1 = Series(tf1, -tf2)
>>> S1.is_biproper
False
>>> S2 = Series(tf2, tf3)
>>> S2.is_biproper
True
"""
return self.doit().is_biproper
def _mat_mul_compatible(*args):
"""To check whether shapes are compatible for matrix mul."""
return all(args[i].num_outputs == args[i+1].num_inputs for i in range(len(args)-1))
class MIMOSeries(MIMOLinearTimeInvariant):
r"""
A class for representing a series configuration of MIMO systems.
Parameters
==========
args : MIMOLinearTimeInvariant
MIMO systems in a series configuration.
evaluate : Boolean, Keyword
When passed ``True``, returns the equivalent
``MIMOSeries(*args).doit()``. Set to ``False`` by default.
Raises
======
ValueError
When no argument is passed.
``var`` attribute is not same for every system.
``num_outputs`` of the MIMO system is not equal to the
``num_inputs`` of its adjacent MIMO system. (Matrix
multiplication constraint, basically)
TypeError
Any of the passed ``*args`` has unsupported type
A combination of SISO and MIMO systems is
passed. There should be homogeneity in the
type of systems passed, MIMO in this case.
Examples
========
>>> from sympy.abc import s
>>> from sympy.physics.control.lti import MIMOSeries, TransferFunctionMatrix
>>> from sympy import Matrix, pprint
>>> mat_a = Matrix([[5*s], [5]]) # 2 Outputs 1 Input
>>> mat_b = Matrix([[5, 1/(6*s**2)]]) # 1 Output 2 Inputs
>>> mat_c = Matrix([[1, s], [5/s, 1]]) # 2 Outputs 2 Inputs
>>> tfm_a = TransferFunctionMatrix.from_Matrix(mat_a, s)
>>> tfm_b = TransferFunctionMatrix.from_Matrix(mat_b, s)
>>> tfm_c = TransferFunctionMatrix.from_Matrix(mat_c, s)
>>> MIMOSeries(tfm_c, tfm_b, tfm_a)
MIMOSeries(TransferFunctionMatrix(((TransferFunction(1, 1, s), TransferFunction(s, 1, s)), (TransferFunction(5, s, s), TransferFunction(1, 1, s)))), TransferFunctionMatrix(((TransferFunction(5, 1, s), TransferFunction(1, 6*s**2, s)),)), TransferFunctionMatrix(((TransferFunction(5*s, 1, s),), (TransferFunction(5, 1, s),))))
>>> pprint(_, use_unicode=False) # For Better Visualization
[5*s] [1 s]
[---] [5 1 ] [- -]
[ 1 ] [- ----] [1 1]
[ ] *[1 2] *[ ]
[ 5 ] [ 6*s ]{t} [5 1]
[ - ] [- -]
[ 1 ]{t} [s 1]{t}
>>> MIMOSeries(tfm_c, tfm_b, tfm_a).doit()
TransferFunctionMatrix(((TransferFunction(150*s**4 + 25*s, 6*s**3, s), TransferFunction(150*s**4 + 5*s, 6*s**2, s)), (TransferFunction(150*s**3 + 25, 6*s**3, s), TransferFunction(150*s**3 + 5, 6*s**2, s))))
>>> pprint(_, use_unicode=False) # (2 Inputs -A-> 2 Outputs) -> (2 Inputs -B-> 1 Output) -> (1 Input -C-> 2 Outputs) is equivalent to (2 Inputs -Series Equivalent-> 2 Outputs).
[ 4 4 ]
[150*s + 25*s 150*s + 5*s]
[------------- ------------]
[ 3 2 ]
[ 6*s 6*s ]
[ ]
[ 3 3 ]
[ 150*s + 25 150*s + 5 ]
[ ----------- ---------- ]
[ 3 2 ]
[ 6*s 6*s ]{t}
Notes
=====
All the transfer function matrices should use the same complex variable ``var`` of the Laplace transform.
``MIMOSeries(A, B)`` is not equivalent to ``A*B``. It is always in the reverse order, that is ``B*A``.
See Also
========
Series, MIMOParallel
"""
def __new__(cls, *args, evaluate=False):
cls._check_args(args)
if _mat_mul_compatible(*args):
obj = super().__new__(cls, *args)
else:
raise ValueError(filldedent("""
Number of input signals do not match the number
of output signals of adjacent systems for some args."""))
return obj.doit() if evaluate else obj
@property
def var(self):
"""
Returns the complex variable used by all the transfer functions.
Examples
========
>>> from sympy.abc import p
>>> from sympy.physics.control.lti import TransferFunction, MIMOSeries, TransferFunctionMatrix
>>> G1 = TransferFunction(p**2 + 2*p + 4, p - 6, p)
>>> G2 = TransferFunction(p, 4 - p, p)
>>> G3 = TransferFunction(0, p**4 - 1, p)
>>> tfm_1 = TransferFunctionMatrix([[G1, G2, G3]])
>>> tfm_2 = TransferFunctionMatrix([[G1], [G2], [G3]])
>>> MIMOSeries(tfm_2, tfm_1).var
p
"""
return self.args[0].var
@property
def num_inputs(self):
"""Returns the number of input signals of the series system."""
return self.args[0].num_inputs
@property
def num_outputs(self):
"""Returns the number of output signals of the series system."""
return self.args[-1].num_outputs
@property
def shape(self):
"""Returns the shape of the equivalent MIMO system."""
return self.num_outputs, self.num_inputs
def doit(self, cancel=False, **kwargs):
"""
Returns the resultant transfer function matrix obtained after evaluating
the MIMO systems arranged in a series configuration.
Examples
========
>>> from sympy.abc import s, p, a, b
>>> from sympy.physics.control.lti import TransferFunction, MIMOSeries, TransferFunctionMatrix
>>> tf1 = TransferFunction(a*p**2 + b*s, s - p, s)
>>> tf2 = TransferFunction(s**3 - 2, s**4 + 5*s + 6, s)
>>> tfm1 = TransferFunctionMatrix([[tf1, tf2], [tf2, tf2]])
>>> tfm2 = TransferFunctionMatrix([[tf2, tf1], [tf1, tf1]])
>>> MIMOSeries(tfm2, tfm1).doit()
TransferFunctionMatrix(((TransferFunction(2*(-p + s)*(s**3 - 2)*(a*p**2 + b*s)*(s**4 + 5*s + 6), (-p + s)**2*(s**4 + 5*s + 6)**2, s), TransferFunction((-p + s)**2*(s**3 - 2)*(a*p**2 + b*s) + (-p + s)*(a*p**2 + b*s)**2*(s**4 + 5*s + 6), (-p + s)**3*(s**4 + 5*s + 6), s)), (TransferFunction((-p + s)*(s**3 - 2)**2*(s**4 + 5*s + 6) + (s**3 - 2)*(a*p**2 + b*s)*(s**4 + 5*s + 6)**2, (-p + s)*(s**4 + 5*s + 6)**3, s), TransferFunction(2*(s**3 - 2)*(a*p**2 + b*s), (-p + s)*(s**4 + 5*s + 6), s))))
"""
_arg = (arg.doit()._expr_mat for arg in reversed(self.args))
if cancel:
res = MatMul(*_arg, evaluate=True)
return TransferFunctionMatrix.from_Matrix(res, self.var)
_dummy_args, _dummy_dict = _dummify_args(_arg, self.var)
res = MatMul(*_dummy_args, evaluate=True)
temp_tfm = TransferFunctionMatrix.from_Matrix(res, self.var)
return temp_tfm.subs(_dummy_dict)
def _eval_rewrite_as_TransferFunctionMatrix(self, *args, **kwargs):
return self.doit()
@_check_other_MIMO
def __add__(self, other):
if isinstance(other, MIMOParallel):
arg_list = list(other.args)
return MIMOParallel(self, *arg_list)
return MIMOParallel(self, other)
__radd__ = __add__
@_check_other_MIMO
def __sub__(self, other):
return self + (-other)
def __rsub__(self, other):
return -self + other
@_check_other_MIMO
def __mul__(self, other):
if isinstance(other, MIMOSeries):
self_arg_list = list(self.args)
other_arg_list = list(other.args)
return MIMOSeries(*other_arg_list, *self_arg_list) # A*B = MIMOSeries(B, A)
arg_list = list(self.args)
return MIMOSeries(other, *arg_list)
def __neg__(self):
arg_list = list(self.args)
arg_list[0] = -arg_list[0]
return MIMOSeries(*arg_list)
class Parallel(SISOLinearTimeInvariant):
r"""
A class for representing a parallel configuration of SISO systems.
Parameters
==========
args : SISOLinearTimeInvariant
SISO systems in a parallel arrangement.
evaluate : Boolean, Keyword
When passed ``True``, returns the equivalent
``Parallel(*args).doit()``. Set to ``False`` by default.
Raises
======
ValueError
When no argument is passed.
``var`` attribute is not same for every system.
TypeError
Any of the passed ``*args`` has unsupported type
A combination of SISO and MIMO systems is
passed. There should be homogeneity in the
type of systems passed.
Examples
========
>>> from sympy.abc import s, p, a, b
>>> from sympy.physics.control.lti import TransferFunction, Parallel, Series
>>> tf1 = TransferFunction(a*p**2 + b*s, s - p, s)
>>> tf2 = TransferFunction(s**3 - 2, s**4 + 5*s + 6, s)
>>> tf3 = TransferFunction(p**2, p + s, s)
>>> P1 = Parallel(tf1, tf2)
>>> P1
Parallel(TransferFunction(a*p**2 + b*s, -p + s, s), TransferFunction(s**3 - 2, s**4 + 5*s + 6, s))
>>> P1.var
s
>>> P2 = Parallel(tf2, Series(tf3, -tf1))
>>> P2
Parallel(TransferFunction(s**3 - 2, s**4 + 5*s + 6, s), Series(TransferFunction(p**2, p + s, s), TransferFunction(-a*p**2 - b*s, -p + s, s)))
>>> P2.var
s
>>> P3 = Parallel(Series(tf1, tf2), Series(tf2, tf3))
>>> P3
Parallel(Series(TransferFunction(a*p**2 + b*s, -p + s, s), TransferFunction(s**3 - 2, s**4 + 5*s + 6, s)), Series(TransferFunction(s**3 - 2, s**4 + 5*s + 6, s), TransferFunction(p**2, p + s, s)))
>>> P3.var
s
You can get the resultant transfer function by using ``.doit()`` method:
>>> Parallel(tf1, tf2, -tf3).doit()
TransferFunction(-p**2*(-p + s)*(s**4 + 5*s + 6) + (-p + s)*(p + s)*(s**3 - 2) + (p + s)*(a*p**2 + b*s)*(s**4 + 5*s + 6), (-p + s)*(p + s)*(s**4 + 5*s + 6), s)
>>> Parallel(tf2, Series(tf1, -tf3)).doit()
TransferFunction(-p**2*(a*p**2 + b*s)*(s**4 + 5*s + 6) + (-p + s)*(p + s)*(s**3 - 2), (-p + s)*(p + s)*(s**4 + 5*s + 6), s)
Notes
=====
All the transfer functions should use the same complex variable
``var`` of the Laplace transform.
See Also
========
Series, TransferFunction, Feedback
"""
def __new__(cls, *args, evaluate=False):
args = _flatten_args(args, Parallel)
cls._check_args(args)
obj = super().__new__(cls, *args)
return obj.doit() if evaluate else obj
@property
def var(self):
"""
Returns the complex variable used by all the transfer functions.
Examples
========
>>> from sympy.abc import p
>>> from sympy.physics.control.lti import TransferFunction, Parallel, Series
>>> G1 = TransferFunction(p**2 + 2*p + 4, p - 6, p)
>>> G2 = TransferFunction(p, 4 - p, p)
>>> G3 = TransferFunction(0, p**4 - 1, p)
>>> Parallel(G1, G2).var
p
>>> Parallel(-G3, Series(G1, G2)).var
p
"""
return self.args[0].var
def doit(self, **hints):
"""
Returns the resultant transfer function obtained after evaluating
the transfer functions in parallel configuration.
Examples
========
>>> from sympy.abc import s, p, a, b
>>> from sympy.physics.control.lti import TransferFunction, Parallel
>>> tf1 = TransferFunction(a*p**2 + b*s, s - p, s)
>>> tf2 = TransferFunction(s**3 - 2, s**4 + 5*s + 6, s)
>>> Parallel(tf2, tf1).doit()
TransferFunction((-p + s)*(s**3 - 2) + (a*p**2 + b*s)*(s**4 + 5*s + 6), (-p + s)*(s**4 + 5*s + 6), s)
>>> Parallel(-tf1, -tf2).doit()
TransferFunction((2 - s**3)*(-p + s) + (-a*p**2 - b*s)*(s**4 + 5*s + 6), (-p + s)*(s**4 + 5*s + 6), s)
"""
_arg = (arg.doit().to_expr() for arg in self.args)
res = Add(*_arg).as_numer_denom()
return TransferFunction(*res, self.var)
def _eval_rewrite_as_TransferFunction(self, *args, **kwargs):
return self.doit()
@_check_other_SISO
def __add__(self, other):
self_arg_list = list(self.args)
return Parallel(*self_arg_list, other)
__radd__ = __add__
@_check_other_SISO
def __sub__(self, other):
return self + (-other)
def __rsub__(self, other):
return -self + other
@_check_other_SISO
def __mul__(self, other):
if isinstance(other, Series):
arg_list = list(other.args)
return Series(self, *arg_list)
return Series(self, other)
def __neg__(self):
return Series(TransferFunction(-1, 1, self.var), self)
def to_expr(self):
"""Returns the equivalent ``Expr`` object."""
return Add(*(arg.to_expr() for arg in self.args), evaluate=False)
@property
def is_proper(self):
"""
Returns True if degree of the numerator polynomial of the resultant transfer
function is less than or equal to degree of the denominator polynomial of
the same, else False.
Examples
========
>>> from sympy.abc import s, p, a, b
>>> from sympy.physics.control.lti import TransferFunction, Parallel
>>> tf1 = TransferFunction(b*s**2 + p**2 - a*p + s, b - p**2, s)
>>> tf2 = TransferFunction(p**2 - 4*p, p**3 + 3*s + 2, s)
>>> tf3 = TransferFunction(s, s**2 + s + 1, s)
>>> P1 = Parallel(-tf2, tf1)
>>> P1.is_proper
False
>>> P2 = Parallel(tf2, tf3)
>>> P2.is_proper
True
"""
return self.doit().is_proper
@property
def is_strictly_proper(self):
"""
Returns True if degree of the numerator polynomial of the resultant transfer
function is strictly less than degree of the denominator polynomial of
the same, else False.
Examples
========
>>> from sympy.abc import s, p, a, b
>>> from sympy.physics.control.lti import TransferFunction, Parallel
>>> tf1 = TransferFunction(a*p**2 + b*s, s - p, s)
>>> tf2 = TransferFunction(s**3 - 2, s**4 + 5*s + 6, s)
>>> tf3 = TransferFunction(s, s**2 + s + 1, s)
>>> P1 = Parallel(tf1, tf2)
>>> P1.is_strictly_proper
False
>>> P2 = Parallel(tf2, tf3)
>>> P2.is_strictly_proper
True
"""
return self.doit().is_strictly_proper
@property
def is_biproper(self):
"""
Returns True if degree of the numerator polynomial of the resultant transfer
function is equal to degree of the denominator polynomial of
the same, else False.
Examples
========
>>> from sympy.abc import s, p, a, b
>>> from sympy.physics.control.lti import TransferFunction, Parallel
>>> tf1 = TransferFunction(a*p**2 + b*s, s - p, s)
>>> tf2 = TransferFunction(p**2, p + s, s)
>>> tf3 = TransferFunction(s, s**2 + s + 1, s)
>>> P1 = Parallel(tf1, -tf2)
>>> P1.is_biproper
True
>>> P2 = Parallel(tf2, tf3)
>>> P2.is_biproper
False
"""
return self.doit().is_biproper
class MIMOParallel(MIMOLinearTimeInvariant):
r"""
A class for representing a parallel configuration of MIMO systems.
Parameters
==========
args : MIMOLinearTimeInvariant
MIMO Systems in a parallel arrangement.
evaluate : Boolean, Keyword
When passed ``True``, returns the equivalent
``MIMOParallel(*args).doit()``. Set to ``False`` by default.
Raises
======
ValueError
When no argument is passed.
``var`` attribute is not same for every system.
All MIMO systems passed do not have same shape.
TypeError
Any of the passed ``*args`` has unsupported type
A combination of SISO and MIMO systems is
passed. There should be homogeneity in the
type of systems passed, MIMO in this case.
Examples
========
>>> from sympy.abc import s
>>> from sympy.physics.control.lti import TransferFunctionMatrix, MIMOParallel
>>> from sympy import Matrix, pprint
>>> expr_1 = 1/s
>>> expr_2 = s/(s**2-1)
>>> expr_3 = (2 + s)/(s**2 - 1)
>>> expr_4 = 5
>>> tfm_a = TransferFunctionMatrix.from_Matrix(Matrix([[expr_1, expr_2], [expr_3, expr_4]]), s)
>>> tfm_b = TransferFunctionMatrix.from_Matrix(Matrix([[expr_2, expr_1], [expr_4, expr_3]]), s)
>>> tfm_c = TransferFunctionMatrix.from_Matrix(Matrix([[expr_3, expr_4], [expr_1, expr_2]]), s)
>>> MIMOParallel(tfm_a, tfm_b, tfm_c)
MIMOParallel(TransferFunctionMatrix(((TransferFunction(1, s, s), TransferFunction(s, s**2 - 1, s)), (TransferFunction(s + 2, s**2 - 1, s), TransferFunction(5, 1, s)))), TransferFunctionMatrix(((TransferFunction(s, s**2 - 1, s), TransferFunction(1, s, s)), (TransferFunction(5, 1, s), TransferFunction(s + 2, s**2 - 1, s)))), TransferFunctionMatrix(((TransferFunction(s + 2, s**2 - 1, s), TransferFunction(5, 1, s)), (TransferFunction(1, s, s), TransferFunction(s, s**2 - 1, s)))))
>>> pprint(_, use_unicode=False) # For Better Visualization
[ 1 s ] [ s 1 ] [s + 2 5 ]
[ - ------] [------ - ] [------ - ]
[ s 2 ] [ 2 s ] [ 2 1 ]
[ s - 1] [s - 1 ] [s - 1 ]
[ ] + [ ] + [ ]
[s + 2 5 ] [ 5 s + 2 ] [ 1 s ]
[------ - ] [ - ------] [ - ------]
[ 2 1 ] [ 1 2 ] [ s 2 ]
[s - 1 ]{t} [ s - 1]{t} [ s - 1]{t}
>>> MIMOParallel(tfm_a, tfm_b, tfm_c).doit()
TransferFunctionMatrix(((TransferFunction(s**2 + s*(2*s + 2) - 1, s*(s**2 - 1), s), TransferFunction(2*s**2 + 5*s*(s**2 - 1) - 1, s*(s**2 - 1), s)), (TransferFunction(s**2 + s*(s + 2) + 5*s*(s**2 - 1) - 1, s*(s**2 - 1), s), TransferFunction(5*s**2 + 2*s - 3, s**2 - 1, s))))
>>> pprint(_, use_unicode=False)
[ 2 2 / 2 \ ]
[ s + s*(2*s + 2) - 1 2*s + 5*s*\s - 1/ - 1]
[ -------------------- -----------------------]
[ / 2 \ / 2 \ ]
[ s*\s - 1/ s*\s - 1/ ]
[ ]
[ 2 / 2 \ 2 ]
[s + s*(s + 2) + 5*s*\s - 1/ - 1 5*s + 2*s - 3 ]
[--------------------------------- -------------- ]
[ / 2 \ 2 ]
[ s*\s - 1/ s - 1 ]{t}
Notes
=====
All the transfer function matrices should use the same complex variable
``var`` of the Laplace transform.
See Also
========
Parallel, MIMOSeries
"""
def __new__(cls, *args, evaluate=False):
args = _flatten_args(args, MIMOParallel)
cls._check_args(args)
if any(arg.shape != args[0].shape for arg in args):
raise TypeError("Shape of all the args is not equal.")
obj = super().__new__(cls, *args)
return obj.doit() if evaluate else obj
@property
def var(self):
"""
Returns the complex variable used by all the systems.
Examples
========
>>> from sympy.abc import p
>>> from sympy.physics.control.lti import TransferFunction, TransferFunctionMatrix, MIMOParallel
>>> G1 = TransferFunction(p**2 + 2*p + 4, p - 6, p)
>>> G2 = TransferFunction(p, 4 - p, p)
>>> G3 = TransferFunction(0, p**4 - 1, p)
>>> G4 = TransferFunction(p**2, p**2 - 1, p)
>>> tfm_a = TransferFunctionMatrix([[G1, G2], [G3, G4]])
>>> tfm_b = TransferFunctionMatrix([[G2, G1], [G4, G3]])
>>> MIMOParallel(tfm_a, tfm_b).var
p
"""
return self.args[0].var
@property
def num_inputs(self):
"""Returns the number of input signals of the parallel system."""
return self.args[0].num_inputs
@property
def num_outputs(self):
"""Returns the number of output signals of the parallel system."""
return self.args[0].num_outputs
@property
def shape(self):
"""Returns the shape of the equivalent MIMO system."""
return self.num_outputs, self.num_inputs
def doit(self, **hints):
"""
Returns the resultant transfer function matrix obtained after evaluating
the MIMO systems arranged in a parallel configuration.
Examples
========
>>> from sympy.abc import s, p, a, b
>>> from sympy.physics.control.lti import TransferFunction, MIMOParallel, TransferFunctionMatrix
>>> tf1 = TransferFunction(a*p**2 + b*s, s - p, s)
>>> tf2 = TransferFunction(s**3 - 2, s**4 + 5*s + 6, s)
>>> tfm_1 = TransferFunctionMatrix([[tf1, tf2], [tf2, tf1]])
>>> tfm_2 = TransferFunctionMatrix([[tf2, tf1], [tf1, tf2]])
>>> MIMOParallel(tfm_1, tfm_2).doit()
TransferFunctionMatrix(((TransferFunction((-p + s)*(s**3 - 2) + (a*p**2 + b*s)*(s**4 + 5*s + 6), (-p + s)*(s**4 + 5*s + 6), s), TransferFunction((-p + s)*(s**3 - 2) + (a*p**2 + b*s)*(s**4 + 5*s + 6), (-p + s)*(s**4 + 5*s + 6), s)), (TransferFunction((-p + s)*(s**3 - 2) + (a*p**2 + b*s)*(s**4 + 5*s + 6), (-p + s)*(s**4 + 5*s + 6), s), TransferFunction((-p + s)*(s**3 - 2) + (a*p**2 + b*s)*(s**4 + 5*s + 6), (-p + s)*(s**4 + 5*s + 6), s))))
"""
_arg = (arg.doit()._expr_mat for arg in self.args)
res = MatAdd(*_arg, evaluate=True)
return TransferFunctionMatrix.from_Matrix(res, self.var)
def _eval_rewrite_as_TransferFunctionMatrix(self, *args, **kwargs):
return self.doit()
@_check_other_MIMO
def __add__(self, other):
self_arg_list = list(self.args)
return MIMOParallel(*self_arg_list, other)
__radd__ = __add__
@_check_other_MIMO
def __sub__(self, other):
return self + (-other)
def __rsub__(self, other):
return -self + other
@_check_other_MIMO
def __mul__(self, other):
if isinstance(other, MIMOSeries):
arg_list = list(other.args)
return MIMOSeries(*arg_list, self)
return MIMOSeries(other, self)
def __neg__(self):
arg_list = [-arg for arg in list(self.args)]
return MIMOParallel(*arg_list)
class Feedback(TransferFunction):
r"""
A class for representing closed-loop feedback interconnection between two
SISO input/output systems.
The first argument, ``sys1``, is the feedforward part of the closed-loop
system or in simple words, the dynamical model representing the process
to be controlled. The second argument, ``sys2``, is the feedback system
and controls the fed back signal to ``sys1``. Both ``sys1`` and ``sys2``
can either be ``Series`` or ``TransferFunction`` objects.
Parameters
==========
sys1 : Series, TransferFunction
The feedforward path system.
sys2 : Series, TransferFunction, optional
The feedback path system (often a feedback controller).
It is the model sitting on the feedback path.
If not specified explicitly, the sys2 is
assumed to be unit (1.0) transfer function.
sign : int, optional
The sign of feedback. Can either be ``1``
(for positive feedback) or ``-1`` (for negative feedback).
Default value is `-1`.
Raises
======
ValueError
When ``sys1`` and ``sys2`` are not using the
same complex variable of the Laplace transform.
When a combination of ``sys1`` and ``sys2`` yields
zero denominator.
TypeError
When either ``sys1`` or ``sys2`` is not a ``Series`` or a
``TransferFunction`` object.
Examples
========
>>> from sympy.abc import s
>>> from sympy.physics.control.lti import TransferFunction, Feedback
>>> plant = TransferFunction(3*s**2 + 7*s - 3, s**2 - 4*s + 2, s)
>>> controller = TransferFunction(5*s - 10, s + 7, s)
>>> F1 = Feedback(plant, controller)
>>> F1
Feedback(TransferFunction(3*s**2 + 7*s - 3, s**2 - 4*s + 2, s), TransferFunction(5*s - 10, s + 7, s), -1)
>>> F1.var
s
>>> F1.args
(TransferFunction(3*s**2 + 7*s - 3, s**2 - 4*s + 2, s), TransferFunction(5*s - 10, s + 7, s), -1)
You can get the feedforward and feedback path systems by using ``.sys1`` and ``.sys2`` respectively.
>>> F1.sys1
TransferFunction(3*s**2 + 7*s - 3, s**2 - 4*s + 2, s)
>>> F1.sys2
TransferFunction(5*s - 10, s + 7, s)
You can get the resultant closed loop transfer function obtained by negative feedback
interconnection using ``.doit()`` method.
>>> F1.doit()
TransferFunction((s + 7)*(s**2 - 4*s + 2)*(3*s**2 + 7*s - 3), ((s + 7)*(s**2 - 4*s + 2) + (5*s - 10)*(3*s**2 + 7*s - 3))*(s**2 - 4*s + 2), s)
>>> G = TransferFunction(2*s**2 + 5*s + 1, s**2 + 2*s + 3, s)
>>> C = TransferFunction(5*s + 10, s + 10, s)
>>> F2 = Feedback(G*C, TransferFunction(1, 1, s))
>>> F2.doit()
TransferFunction((s + 10)*(5*s + 10)*(s**2 + 2*s + 3)*(2*s**2 + 5*s + 1), (s + 10)*((s + 10)*(s**2 + 2*s + 3) + (5*s + 10)*(2*s**2 + 5*s + 1))*(s**2 + 2*s + 3), s)
To negate a ``Feedback`` object, the ``-`` operator can be prepended:
>>> -F1
Feedback(TransferFunction(-3*s**2 - 7*s + 3, s**2 - 4*s + 2, s), TransferFunction(10 - 5*s, s + 7, s), -1)
>>> -F2
Feedback(Series(TransferFunction(-1, 1, s), TransferFunction(2*s**2 + 5*s + 1, s**2 + 2*s + 3, s), TransferFunction(5*s + 10, s + 10, s)), TransferFunction(-1, 1, s), -1)
See Also
========
MIMOFeedback, Series, Parallel
"""
def __new__(cls, sys1, sys2=None, sign=-1):
if not sys2:
sys2 = TransferFunction(1, 1, sys1.var)
if not (isinstance(sys1, (TransferFunction, Series, Feedback))
and isinstance(sys2, (TransferFunction, Series, Feedback))):
raise TypeError("Unsupported type for `sys1` or `sys2` of Feedback.")
if sign not in [-1, 1]:
raise ValueError(filldedent("""
Unsupported type for feedback. `sign` arg should
either be 1 (positive feedback loop) or -1
(negative feedback loop)."""))
if Mul(sys1.to_expr(), sys2.to_expr()).simplify() == sign:
raise ValueError("The equivalent system will have zero denominator.")
if sys1.var != sys2.var:
raise ValueError(filldedent("""
Both `sys1` and `sys2` should be using the
same complex variable."""))
return super(TransferFunction, cls).__new__(cls, sys1, sys2, _sympify(sign))
@property
def sys1(self):
"""
Returns the feedforward system of the feedback interconnection.
Examples
========
>>> from sympy.abc import s, p
>>> from sympy.physics.control.lti import TransferFunction, Feedback
>>> plant = TransferFunction(3*s**2 + 7*s - 3, s**2 - 4*s + 2, s)
>>> controller = TransferFunction(5*s - 10, s + 7, s)
>>> F1 = Feedback(plant, controller)
>>> F1.sys1
TransferFunction(3*s**2 + 7*s - 3, s**2 - 4*s + 2, s)
>>> G = TransferFunction(2*s**2 + 5*s + 1, p**2 + 2*p + 3, p)
>>> C = TransferFunction(5*p + 10, p + 10, p)
>>> P = TransferFunction(1 - s, p + 2, p)
>>> F2 = Feedback(TransferFunction(1, 1, p), G*C*P)
>>> F2.sys1
TransferFunction(1, 1, p)
"""
return self.args[0]
@property
def sys2(self):
"""
Returns the feedback controller of the feedback interconnection.
Examples
========
>>> from sympy.abc import s, p
>>> from sympy.physics.control.lti import TransferFunction, Feedback
>>> plant = TransferFunction(3*s**2 + 7*s - 3, s**2 - 4*s + 2, s)
>>> controller = TransferFunction(5*s - 10, s + 7, s)
>>> F1 = Feedback(plant, controller)
>>> F1.sys2
TransferFunction(5*s - 10, s + 7, s)
>>> G = TransferFunction(2*s**2 + 5*s + 1, p**2 + 2*p + 3, p)
>>> C = TransferFunction(5*p + 10, p + 10, p)
>>> P = TransferFunction(1 - s, p + 2, p)
>>> F2 = Feedback(TransferFunction(1, 1, p), G*C*P)
>>> F2.sys2
Series(TransferFunction(2*s**2 + 5*s + 1, p**2 + 2*p + 3, p), TransferFunction(5*p + 10, p + 10, p), TransferFunction(1 - s, p + 2, p))
"""
return self.args[1]
@property
def var(self):
"""
Returns the complex variable of the Laplace transform used by all
the transfer functions involved in the feedback interconnection.
Examples
========
>>> from sympy.abc import s, p
>>> from sympy.physics.control.lti import TransferFunction, Feedback
>>> plant = TransferFunction(3*s**2 + 7*s - 3, s**2 - 4*s + 2, s)
>>> controller = TransferFunction(5*s - 10, s + 7, s)
>>> F1 = Feedback(plant, controller)
>>> F1.var
s
>>> G = TransferFunction(2*s**2 + 5*s + 1, p**2 + 2*p + 3, p)
>>> C = TransferFunction(5*p + 10, p + 10, p)
>>> P = TransferFunction(1 - s, p + 2, p)
>>> F2 = Feedback(TransferFunction(1, 1, p), G*C*P)
>>> F2.var
p
"""
return self.sys1.var
@property
def sign(self):
"""
Returns the type of MIMO Feedback model. ``1``
for Positive and ``-1`` for Negative.
"""
return self.args[2]
@property
def num(self):
"""
Returns the numerator of the closed loop feedback system.
"""
return self.sys1
@property
def den(self):
"""
Returns the denominator of the closed loop feedback model.
"""
unit = TransferFunction(1, 1, self.var)
arg_list = list(self.sys1.args) if isinstance(self.sys1, Series) else [self.sys1]
if self.sign == 1:
return Parallel(unit, -Series(self.sys2, *arg_list))
return Parallel(unit, Series(self.sys2, *arg_list))
@property
def sensitivity(self):
"""
Returns the sensitivity function of the feedback loop.
Sensitivity of a Feedback system is the ratio
of change in the open loop gain to the change in
the closed loop gain.
.. note::
This method would not return the complementary
sensitivity function.
Examples
========
>>> from sympy.abc import p
>>> from sympy.physics.control.lti import TransferFunction, Feedback
>>> C = TransferFunction(5*p + 10, p + 10, p)
>>> P = TransferFunction(1 - p, p + 2, p)
>>> F_1 = Feedback(P, C)
>>> F_1.sensitivity
1/((1 - p)*(5*p + 10)/((p + 2)*(p + 10)) + 1)
"""
return 1/(1 - self.sign*self.sys1.to_expr()*self.sys2.to_expr())
def doit(self, cancel=False, expand=False, **hints):
"""
Returns the resultant transfer function obtained by the
feedback interconnection.
Examples
========
>>> from sympy.abc import s
>>> from sympy.physics.control.lti import TransferFunction, Feedback
>>> plant = TransferFunction(3*s**2 + 7*s - 3, s**2 - 4*s + 2, s)
>>> controller = TransferFunction(5*s - 10, s + 7, s)
>>> F1 = Feedback(plant, controller)
>>> F1.doit()
TransferFunction((s + 7)*(s**2 - 4*s + 2)*(3*s**2 + 7*s - 3), ((s + 7)*(s**2 - 4*s + 2) + (5*s - 10)*(3*s**2 + 7*s - 3))*(s**2 - 4*s + 2), s)
>>> G = TransferFunction(2*s**2 + 5*s + 1, s**2 + 2*s + 3, s)
>>> F2 = Feedback(G, TransferFunction(1, 1, s))
>>> F2.doit()
TransferFunction((s**2 + 2*s + 3)*(2*s**2 + 5*s + 1), (s**2 + 2*s + 3)*(3*s**2 + 7*s + 4), s)
Use kwarg ``expand=True`` to expand the resultant transfer function.
Use ``cancel=True`` to cancel out the common terms in numerator and
denominator.
>>> F2.doit(cancel=True, expand=True)
TransferFunction(2*s**2 + 5*s + 1, 3*s**2 + 7*s + 4, s)
>>> F2.doit(expand=True)
TransferFunction(2*s**4 + 9*s**3 + 17*s**2 + 17*s + 3, 3*s**4 + 13*s**3 + 27*s**2 + 29*s + 12, s)
"""
arg_list = list(self.sys1.args) if isinstance(self.sys1, Series) else [self.sys1]
# F_n and F_d are resultant TFs of num and den of Feedback.
F_n, unit = self.sys1.doit(), TransferFunction(1, 1, self.sys1.var)
if self.sign == -1:
F_d = Parallel(unit, Series(self.sys2, *arg_list)).doit()
else:
F_d = Parallel(unit, -Series(self.sys2, *arg_list)).doit()
_resultant_tf = TransferFunction(F_n.num * F_d.den, F_n.den * F_d.num, F_n.var)
if cancel:
_resultant_tf = _resultant_tf.simplify()
if expand:
_resultant_tf = _resultant_tf.expand()
return _resultant_tf
def _eval_rewrite_as_TransferFunction(self, num, den, sign, **kwargs):
return self.doit()
def to_expr(self):
"""
Converts a ``Feedback`` object to SymPy Expr.
Examples
========
>>> from sympy.abc import s, a, b
>>> from sympy.physics.control.lti import TransferFunction, Feedback
>>> from sympy import Expr
>>> tf1 = TransferFunction(a+s, 1, s)
>>> tf2 = TransferFunction(b+s, 1, s)
>>> fd1 = Feedback(tf1, tf2)
>>> fd1.to_expr()
(a + s)/((a + s)*(b + s) + 1)
>>> isinstance(_, Expr)
True
"""
return self.doit().to_expr()
def __neg__(self):
return Feedback(-self.sys1, -self.sys2, self.sign)
def _is_invertible(a, b, sign):
"""
Checks whether a given pair of MIMO
systems passed is invertible or not.
"""
_mat = eye(a.num_outputs) - sign*(a.doit()._expr_mat)*(b.doit()._expr_mat)
_det = _mat.det()
return _det != 0
class MIMOFeedback(MIMOLinearTimeInvariant):
r"""
A class for representing closed-loop feedback interconnection between two
MIMO input/output systems.
Parameters
==========
sys1 : MIMOSeries, TransferFunctionMatrix
The MIMO system placed on the feedforward path.
sys2 : MIMOSeries, TransferFunctionMatrix
The system placed on the feedback path
(often a feedback controller).
sign : int, optional
The sign of feedback. Can either be ``1``
(for positive feedback) or ``-1`` (for negative feedback).
Default value is `-1`.
Raises
======
ValueError
When ``sys1`` and ``sys2`` are not using the
same complex variable of the Laplace transform.
Forward path model should have an equal number of inputs/outputs
to the feedback path outputs/inputs.
When product of ``sys1`` and ``sys2`` is not a square matrix.
When the equivalent MIMO system is not invertible.
TypeError
When either ``sys1`` or ``sys2`` is not a ``MIMOSeries`` or a
``TransferFunctionMatrix`` object.
Examples
========
>>> from sympy import Matrix, pprint
>>> from sympy.abc import s
>>> from sympy.physics.control.lti import TransferFunctionMatrix, MIMOFeedback
>>> plant_mat = Matrix([[1, 1/s], [0, 1]])
>>> controller_mat = Matrix([[10, 0], [0, 10]]) # Constant Gain
>>> plant = TransferFunctionMatrix.from_Matrix(plant_mat, s)
>>> controller = TransferFunctionMatrix.from_Matrix(controller_mat, s)
>>> feedback = MIMOFeedback(plant, controller) # Negative Feedback (default)
>>> pprint(feedback, use_unicode=False)
/ [1 1] [10 0 ] \-1 [1 1]
| [- -] [-- - ] | [- -]
| [1 s] [1 1 ] | [1 s]
|I + [ ] *[ ] | * [ ]
| [0 1] [0 10] | [0 1]
| [- -] [- --] | [- -]
\ [1 1]{t} [1 1 ]{t}/ [1 1]{t}
To get the equivalent system matrix, use either ``doit`` or ``rewrite`` method.
>>> pprint(feedback.doit(), use_unicode=False)
[1 1 ]
[-- -----]
[11 121*s]
[ ]
[0 1 ]
[- -- ]
[1 11 ]{t}
To negate the ``MIMOFeedback`` object, use ``-`` operator.
>>> neg_feedback = -feedback
>>> pprint(neg_feedback.doit(), use_unicode=False)
[-1 -1 ]
[--- -----]
[11 121*s]
[ ]
[ 0 -1 ]
[ - --- ]
[ 1 11 ]{t}
See Also
========
Feedback, MIMOSeries, MIMOParallel
"""
def __new__(cls, sys1, sys2, sign=-1):
if not (isinstance(sys1, (TransferFunctionMatrix, MIMOSeries))
and isinstance(sys2, (TransferFunctionMatrix, MIMOSeries))):
raise TypeError("Unsupported type for `sys1` or `sys2` of MIMO Feedback.")
if sys1.num_inputs != sys2.num_outputs or \
sys1.num_outputs != sys2.num_inputs:
raise ValueError(filldedent("""
Product of `sys1` and `sys2` must
yield a square matrix."""))
if sign not in (-1, 1):
raise ValueError(filldedent("""
Unsupported type for feedback. `sign` arg should
either be 1 (positive feedback loop) or -1
(negative feedback loop)."""))
if not _is_invertible(sys1, sys2, sign):
raise ValueError("Non-Invertible system inputted.")
if sys1.var != sys2.var:
raise ValueError(filldedent("""
Both `sys1` and `sys2` should be using the
same complex variable."""))
return super().__new__(cls, sys1, sys2, _sympify(sign))
@property
def sys1(self):
r"""
Returns the system placed on the feedforward path of the MIMO feedback interconnection.
Examples
========
>>> from sympy import pprint
>>> from sympy.abc import s
>>> from sympy.physics.control.lti import TransferFunction, TransferFunctionMatrix, MIMOFeedback
>>> tf1 = TransferFunction(s**2 + s + 1, s**2 - s + 1, s)
>>> tf2 = TransferFunction(1, s, s)
>>> tf3 = TransferFunction(1, 1, s)
>>> sys1 = TransferFunctionMatrix([[tf1, tf2], [tf2, tf1]])
>>> sys2 = TransferFunctionMatrix([[tf3, tf3], [tf3, tf2]])
>>> F_1 = MIMOFeedback(sys1, sys2, 1)
>>> F_1.sys1
TransferFunctionMatrix(((TransferFunction(s**2 + s + 1, s**2 - s + 1, s), TransferFunction(1, s, s)), (TransferFunction(1, s, s), TransferFunction(s**2 + s + 1, s**2 - s + 1, s))))
>>> pprint(_, use_unicode=False)
[ 2 ]
[s + s + 1 1 ]
[---------- - ]
[ 2 s ]
[s - s + 1 ]
[ ]
[ 2 ]
[ 1 s + s + 1]
[ - ----------]
[ s 2 ]
[ s - s + 1]{t}
"""
return self.args[0]
@property
def sys2(self):
r"""
Returns the feedback controller of the MIMO feedback interconnection.
Examples
========
>>> from sympy import pprint
>>> from sympy.abc import s
>>> from sympy.physics.control.lti import TransferFunction, TransferFunctionMatrix, MIMOFeedback
>>> tf1 = TransferFunction(s**2, s**3 - s + 1, s)
>>> tf2 = TransferFunction(1, s, s)
>>> tf3 = TransferFunction(1, 1, s)
>>> sys1 = TransferFunctionMatrix([[tf1, tf2], [tf2, tf1]])
>>> sys2 = TransferFunctionMatrix([[tf1, tf3], [tf3, tf2]])
>>> F_1 = MIMOFeedback(sys1, sys2)
>>> F_1.sys2
TransferFunctionMatrix(((TransferFunction(s**2, s**3 - s + 1, s), TransferFunction(1, 1, s)), (TransferFunction(1, 1, s), TransferFunction(1, s, s))))
>>> pprint(_, use_unicode=False)
[ 2 ]
[ s 1]
[---------- -]
[ 3 1]
[s - s + 1 ]
[ ]
[ 1 1]
[ - -]
[ 1 s]{t}
"""
return self.args[1]
@property
def var(self):
r"""
Returns the complex variable of the Laplace transform used by all
the transfer functions involved in the MIMO feedback loop.
Examples
========
>>> from sympy.abc import p
>>> from sympy.physics.control.lti import TransferFunction, TransferFunctionMatrix, MIMOFeedback
>>> tf1 = TransferFunction(p, 1 - p, p)
>>> tf2 = TransferFunction(1, p, p)
>>> tf3 = TransferFunction(1, 1, p)
>>> sys1 = TransferFunctionMatrix([[tf1, tf2], [tf2, tf1]])
>>> sys2 = TransferFunctionMatrix([[tf1, tf3], [tf3, tf2]])
>>> F_1 = MIMOFeedback(sys1, sys2, 1) # Positive feedback
>>> F_1.var
p
"""
return self.sys1.var
@property
def sign(self):
r"""
Returns the type of feedback interconnection of two models. ``1``
for Positive and ``-1`` for Negative.
"""
return self.args[2]
@property
def sensitivity(self):
r"""
Returns the sensitivity function matrix of the feedback loop.
Sensitivity of a closed-loop system is the ratio of change
in the open loop gain to the change in the closed loop gain.
.. note::
This method would not return the complementary
sensitivity function.
Examples
========
>>> from sympy import pprint
>>> from sympy.abc import p
>>> from sympy.physics.control.lti import TransferFunction, TransferFunctionMatrix, MIMOFeedback
>>> tf1 = TransferFunction(p, 1 - p, p)
>>> tf2 = TransferFunction(1, p, p)
>>> tf3 = TransferFunction(1, 1, p)
>>> sys1 = TransferFunctionMatrix([[tf1, tf2], [tf2, tf1]])
>>> sys2 = TransferFunctionMatrix([[tf1, tf3], [tf3, tf2]])
>>> F_1 = MIMOFeedback(sys1, sys2, 1) # Positive feedback
>>> F_2 = MIMOFeedback(sys1, sys2) # Negative feedback
>>> pprint(F_1.sensitivity, use_unicode=False)
[ 4 3 2 5 4 2 ]
[- p + 3*p - 4*p + 3*p - 1 p - 2*p + 3*p - 3*p + 1 ]
[---------------------------- -----------------------------]
[ 4 3 2 5 4 3 2 ]
[ p + 3*p - 8*p + 8*p - 3 p + 3*p - 8*p + 8*p - 3*p]
[ ]
[ 4 3 2 3 2 ]
[ p - p - p + p 3*p - 6*p + 4*p - 1 ]
[ -------------------------- -------------------------- ]
[ 4 3 2 4 3 2 ]
[ p + 3*p - 8*p + 8*p - 3 p + 3*p - 8*p + 8*p - 3 ]
>>> pprint(F_2.sensitivity, use_unicode=False)
[ 4 3 2 5 4 2 ]
[p - 3*p + 2*p + p - 1 p - 2*p + 3*p - 3*p + 1]
[------------------------ --------------------------]
[ 4 3 5 4 2 ]
[ p - 3*p + 2*p - 1 p - 3*p + 2*p - p ]
[ ]
[ 4 3 2 4 3 ]
[ p - p - p + p 2*p - 3*p + 2*p - 1 ]
[ ------------------- --------------------- ]
[ 4 3 4 3 ]
[ p - 3*p + 2*p - 1 p - 3*p + 2*p - 1 ]
"""
_sys1_mat = self.sys1.doit()._expr_mat
_sys2_mat = self.sys2.doit()._expr_mat
return (eye(self.sys1.num_inputs) - \
self.sign*_sys1_mat*_sys2_mat).inv()
def doit(self, cancel=True, expand=False, **hints):
r"""
Returns the resultant transfer function matrix obtained by the
feedback interconnection.
Examples
========
>>> from sympy import pprint
>>> from sympy.abc import s
>>> from sympy.physics.control.lti import TransferFunction, TransferFunctionMatrix, MIMOFeedback
>>> tf1 = TransferFunction(s, 1 - s, s)
>>> tf2 = TransferFunction(1, s, s)
>>> tf3 = TransferFunction(5, 1, s)
>>> tf4 = TransferFunction(s - 1, s, s)
>>> tf5 = TransferFunction(0, 1, s)
>>> sys1 = TransferFunctionMatrix([[tf1, tf2], [tf3, tf4]])
>>> sys2 = TransferFunctionMatrix([[tf3, tf5], [tf5, tf5]])
>>> F_1 = MIMOFeedback(sys1, sys2, 1)
>>> pprint(F_1, use_unicode=False)
/ [ s 1 ] [5 0] \-1 [ s 1 ]
| [----- - ] [- -] | [----- - ]
| [1 - s s ] [1 1] | [1 - s s ]
|I - [ ] *[ ] | * [ ]
| [ 5 s - 1] [0 0] | [ 5 s - 1]
| [ - -----] [- -] | [ - -----]
\ [ 1 s ]{t} [1 1]{t}/ [ 1 s ]{t}
>>> pprint(F_1.doit(), use_unicode=False)
[ -s s - 1 ]
[------- ----------- ]
[6*s - 1 s*(6*s - 1) ]
[ ]
[5*s - 5 (s - 1)*(6*s + 24)]
[------- ------------------]
[6*s - 1 s*(6*s - 1) ]{t}
If the user wants the resultant ``TransferFunctionMatrix`` object without
canceling the common factors then the ``cancel`` kwarg should be passed ``False``.
>>> pprint(F_1.doit(cancel=False), use_unicode=False)
[ s*(s - 1) s - 1 ]
[ ----------------- ----------- ]
[ (1 - s)*(6*s - 1) s*(6*s - 1) ]
[ ]
[s*(25*s - 25) + 5*(1 - s)*(6*s - 1) s*(s - 1)*(6*s - 1) + s*(25*s - 25)]
[----------------------------------- -----------------------------------]
[ (1 - s)*(6*s - 1) 2 ]
[ s *(6*s - 1) ]{t}
If the user wants the expanded form of the resultant transfer function matrix,
the ``expand`` kwarg should be passed as ``True``.
>>> pprint(F_1.doit(expand=True), use_unicode=False)
[ -s s - 1 ]
[------- -------- ]
[6*s - 1 2 ]
[ 6*s - s ]
[ ]
[ 2 ]
[5*s - 5 6*s + 18*s - 24]
[------- ----------------]
[6*s - 1 2 ]
[ 6*s - s ]{t}
"""
_mat = self.sensitivity * self.sys1.doit()._expr_mat
_resultant_tfm = _to_TFM(_mat, self.var)
if cancel:
_resultant_tfm = _resultant_tfm.simplify()
if expand:
_resultant_tfm = _resultant_tfm.expand()
return _resultant_tfm
def _eval_rewrite_as_TransferFunctionMatrix(self, sys1, sys2, sign, **kwargs):
return self.doit()
def __neg__(self):
return MIMOFeedback(-self.sys1, -self.sys2, self.sign)
def _to_TFM(mat, var):
"""Private method to convert ImmutableMatrix to TransferFunctionMatrix efficiently"""
to_tf = lambda expr: TransferFunction.from_rational_expression(expr, var)
arg = [[to_tf(expr) for expr in row] for row in mat.tolist()]
return TransferFunctionMatrix(arg)
class TransferFunctionMatrix(MIMOLinearTimeInvariant):
r"""
A class for representing the MIMO (multiple-input and multiple-output)
generalization of the SISO (single-input and single-output) transfer function.
It is a matrix of transfer functions (``TransferFunction``, SISO-``Series`` or SISO-``Parallel``).
There is only one argument, ``arg`` which is also the compulsory argument.
``arg`` is expected to be strictly of the type list of lists
which holds the transfer functions or reducible to transfer functions.
Parameters
==========
arg : Nested ``List`` (strictly).
Users are expected to input a nested list of ``TransferFunction``, ``Series``
and/or ``Parallel`` objects.
Examples
========
.. note::
``pprint()`` can be used for better visualization of ``TransferFunctionMatrix`` objects.
>>> from sympy.abc import s, p, a
>>> from sympy import pprint
>>> from sympy.physics.control.lti import TransferFunction, TransferFunctionMatrix, Series, Parallel
>>> tf_1 = TransferFunction(s + a, s**2 + s + 1, s)
>>> tf_2 = TransferFunction(p**4 - 3*p + 2, s + p, s)
>>> tf_3 = TransferFunction(3, s + 2, s)
>>> tf_4 = TransferFunction(-a + p, 9*s - 9, s)
>>> tfm_1 = TransferFunctionMatrix([[tf_1], [tf_2], [tf_3]])
>>> tfm_1
TransferFunctionMatrix(((TransferFunction(a + s, s**2 + s + 1, s),), (TransferFunction(p**4 - 3*p + 2, p + s, s),), (TransferFunction(3, s + 2, s),)))
>>> tfm_1.var
s
>>> tfm_1.num_inputs
1
>>> tfm_1.num_outputs
3
>>> tfm_1.shape
(3, 1)
>>> tfm_1.args
(((TransferFunction(a + s, s**2 + s + 1, s),), (TransferFunction(p**4 - 3*p + 2, p + s, s),), (TransferFunction(3, s + 2, s),)),)
>>> tfm_2 = TransferFunctionMatrix([[tf_1, -tf_3], [tf_2, -tf_1], [tf_3, -tf_2]])
>>> tfm_2
TransferFunctionMatrix(((TransferFunction(a + s, s**2 + s + 1, s), TransferFunction(-3, s + 2, s)), (TransferFunction(p**4 - 3*p + 2, p + s, s), TransferFunction(-a - s, s**2 + s + 1, s)), (TransferFunction(3, s + 2, s), TransferFunction(-p**4 + 3*p - 2, p + s, s))))
>>> pprint(tfm_2, use_unicode=False) # pretty-printing for better visualization
[ a + s -3 ]
[ ---------- ----- ]
[ 2 s + 2 ]
[ s + s + 1 ]
[ ]
[ 4 ]
[p - 3*p + 2 -a - s ]
[------------ ---------- ]
[ p + s 2 ]
[ s + s + 1 ]
[ ]
[ 4 ]
[ 3 - p + 3*p - 2]
[ ----- --------------]
[ s + 2 p + s ]{t}
TransferFunctionMatrix can be transposed, if user wants to switch the input and output transfer functions
>>> tfm_2.transpose()
TransferFunctionMatrix(((TransferFunction(a + s, s**2 + s + 1, s), TransferFunction(p**4 - 3*p + 2, p + s, s), TransferFunction(3, s + 2, s)), (TransferFunction(-3, s + 2, s), TransferFunction(-a - s, s**2 + s + 1, s), TransferFunction(-p**4 + 3*p - 2, p + s, s))))
>>> pprint(_, use_unicode=False)
[ 4 ]
[ a + s p - 3*p + 2 3 ]
[---------- ------------ ----- ]
[ 2 p + s s + 2 ]
[s + s + 1 ]
[ ]
[ 4 ]
[ -3 -a - s - p + 3*p - 2]
[ ----- ---------- --------------]
[ s + 2 2 p + s ]
[ s + s + 1 ]{t}
>>> tf_5 = TransferFunction(5, s, s)
>>> tf_6 = TransferFunction(5*s, (2 + s**2), s)
>>> tf_7 = TransferFunction(5, (s*(2 + s**2)), s)
>>> tf_8 = TransferFunction(5, 1, s)
>>> tfm_3 = TransferFunctionMatrix([[tf_5, tf_6], [tf_7, tf_8]])
>>> tfm_3
TransferFunctionMatrix(((TransferFunction(5, s, s), TransferFunction(5*s, s**2 + 2, s)), (TransferFunction(5, s*(s**2 + 2), s), TransferFunction(5, 1, s))))
>>> pprint(tfm_3, use_unicode=False)
[ 5 5*s ]
[ - ------]
[ s 2 ]
[ s + 2]
[ ]
[ 5 5 ]
[---------- - ]
[ / 2 \ 1 ]
[s*\s + 2/ ]{t}
>>> tfm_3.var
s
>>> tfm_3.shape
(2, 2)
>>> tfm_3.num_outputs
2
>>> tfm_3.num_inputs
2
>>> tfm_3.args
(((TransferFunction(5, s, s), TransferFunction(5*s, s**2 + 2, s)), (TransferFunction(5, s*(s**2 + 2), s), TransferFunction(5, 1, s))),)
To access the ``TransferFunction`` at any index in the ``TransferFunctionMatrix``, use the index notation.
>>> tfm_3[1, 0] # gives the TransferFunction present at 2nd Row and 1st Col. Similar to that in Matrix classes
TransferFunction(5, s*(s**2 + 2), s)
>>> tfm_3[0, 0] # gives the TransferFunction present at 1st Row and 1st Col.
TransferFunction(5, s, s)
>>> tfm_3[:, 0] # gives the first column
TransferFunctionMatrix(((TransferFunction(5, s, s),), (TransferFunction(5, s*(s**2 + 2), s),)))
>>> pprint(_, use_unicode=False)
[ 5 ]
[ - ]
[ s ]
[ ]
[ 5 ]
[----------]
[ / 2 \]
[s*\s + 2/]{t}
>>> tfm_3[0, :] # gives the first row
TransferFunctionMatrix(((TransferFunction(5, s, s), TransferFunction(5*s, s**2 + 2, s)),))
>>> pprint(_, use_unicode=False)
[5 5*s ]
[- ------]
[s 2 ]
[ s + 2]{t}
To negate a transfer function matrix, ``-`` operator can be prepended:
>>> tfm_4 = TransferFunctionMatrix([[tf_2], [-tf_1], [tf_3]])
>>> -tfm_4
TransferFunctionMatrix(((TransferFunction(-p**4 + 3*p - 2, p + s, s),), (TransferFunction(a + s, s**2 + s + 1, s),), (TransferFunction(-3, s + 2, s),)))
>>> tfm_5 = TransferFunctionMatrix([[tf_1, tf_2], [tf_3, -tf_1]])
>>> -tfm_5
TransferFunctionMatrix(((TransferFunction(-a - s, s**2 + s + 1, s), TransferFunction(-p**4 + 3*p - 2, p + s, s)), (TransferFunction(-3, s + 2, s), TransferFunction(a + s, s**2 + s + 1, s))))
``subs()`` returns the ``TransferFunctionMatrix`` object with the value substituted in the expression. This will not
mutate your original ``TransferFunctionMatrix``.
>>> tfm_2.subs(p, 2) # substituting p everywhere in tfm_2 with 2.
TransferFunctionMatrix(((TransferFunction(a + s, s**2 + s + 1, s), TransferFunction(-3, s + 2, s)), (TransferFunction(12, s + 2, s), TransferFunction(-a - s, s**2 + s + 1, s)), (TransferFunction(3, s + 2, s), TransferFunction(-12, s + 2, s))))
>>> pprint(_, use_unicode=False)
[ a + s -3 ]
[---------- ----- ]
[ 2 s + 2 ]
[s + s + 1 ]
[ ]
[ 12 -a - s ]
[ ----- ----------]
[ s + 2 2 ]
[ s + s + 1]
[ ]
[ 3 -12 ]
[ ----- ----- ]
[ s + 2 s + 2 ]{t}
>>> pprint(tfm_2, use_unicode=False) # State of tfm_2 is unchanged after substitution
[ a + s -3 ]
[ ---------- ----- ]
[ 2 s + 2 ]
[ s + s + 1 ]
[ ]
[ 4 ]
[p - 3*p + 2 -a - s ]
[------------ ---------- ]
[ p + s 2 ]
[ s + s + 1 ]
[ ]
[ 4 ]
[ 3 - p + 3*p - 2]
[ ----- --------------]
[ s + 2 p + s ]{t}
``subs()`` also supports multiple substitutions.
>>> tfm_2.subs({p: 2, a: 1}) # substituting p with 2 and a with 1
TransferFunctionMatrix(((TransferFunction(s + 1, s**2 + s + 1, s), TransferFunction(-3, s + 2, s)), (TransferFunction(12, s + 2, s), TransferFunction(-s - 1, s**2 + s + 1, s)), (TransferFunction(3, s + 2, s), TransferFunction(-12, s + 2, s))))
>>> pprint(_, use_unicode=False)
[ s + 1 -3 ]
[---------- ----- ]
[ 2 s + 2 ]
[s + s + 1 ]
[ ]
[ 12 -s - 1 ]
[ ----- ----------]
[ s + 2 2 ]
[ s + s + 1]
[ ]
[ 3 -12 ]
[ ----- ----- ]
[ s + 2 s + 2 ]{t}
Users can reduce the ``Series`` and ``Parallel`` elements of the matrix to ``TransferFunction`` by using
``doit()``.
>>> tfm_6 = TransferFunctionMatrix([[Series(tf_3, tf_4), Parallel(tf_3, tf_4)]])
>>> tfm_6
TransferFunctionMatrix(((Series(TransferFunction(3, s + 2, s), TransferFunction(-a + p, 9*s - 9, s)), Parallel(TransferFunction(3, s + 2, s), TransferFunction(-a + p, 9*s - 9, s))),))
>>> pprint(tfm_6, use_unicode=False)
[-a + p 3 -a + p 3 ]
[-------*----- ------- + -----]
[9*s - 9 s + 2 9*s - 9 s + 2]{t}
>>> tfm_6.doit()
TransferFunctionMatrix(((TransferFunction(-3*a + 3*p, (s + 2)*(9*s - 9), s), TransferFunction(27*s + (-a + p)*(s + 2) - 27, (s + 2)*(9*s - 9), s)),))
>>> pprint(_, use_unicode=False)
[ -3*a + 3*p 27*s + (-a + p)*(s + 2) - 27]
[----------------- ----------------------------]
[(s + 2)*(9*s - 9) (s + 2)*(9*s - 9) ]{t}
>>> tf_9 = TransferFunction(1, s, s)
>>> tf_10 = TransferFunction(1, s**2, s)
>>> tfm_7 = TransferFunctionMatrix([[Series(tf_9, tf_10), tf_9], [tf_10, Parallel(tf_9, tf_10)]])
>>> tfm_7
TransferFunctionMatrix(((Series(TransferFunction(1, s, s), TransferFunction(1, s**2, s)), TransferFunction(1, s, s)), (TransferFunction(1, s**2, s), Parallel(TransferFunction(1, s, s), TransferFunction(1, s**2, s)))))
>>> pprint(tfm_7, use_unicode=False)
[ 1 1 ]
[---- - ]
[ 2 s ]
[s*s ]
[ ]
[ 1 1 1]
[ -- -- + -]
[ 2 2 s]
[ s s ]{t}
>>> tfm_7.doit()
TransferFunctionMatrix(((TransferFunction(1, s**3, s), TransferFunction(1, s, s)), (TransferFunction(1, s**2, s), TransferFunction(s**2 + s, s**3, s))))
>>> pprint(_, use_unicode=False)
[1 1 ]
[-- - ]
[ 3 s ]
[s ]
[ ]
[ 2 ]
[1 s + s]
[-- ------]
[ 2 3 ]
[s s ]{t}
Addition, subtraction, and multiplication of transfer function matrices can form
unevaluated ``Series`` or ``Parallel`` objects.
- For addition and subtraction:
All the transfer function matrices must have the same shape.
- For multiplication (C = A * B):
The number of inputs of the first transfer function matrix (A) must be equal to the
number of outputs of the second transfer function matrix (B).
Also, use pretty-printing (``pprint``) to analyse better.
>>> tfm_8 = TransferFunctionMatrix([[tf_3], [tf_2], [-tf_1]])
>>> tfm_9 = TransferFunctionMatrix([[-tf_3]])
>>> tfm_10 = TransferFunctionMatrix([[tf_1], [tf_2], [tf_4]])
>>> tfm_11 = TransferFunctionMatrix([[tf_4], [-tf_1]])
>>> tfm_12 = TransferFunctionMatrix([[tf_4, -tf_1, tf_3], [-tf_2, -tf_4, -tf_3]])
>>> tfm_8 + tfm_10
MIMOParallel(TransferFunctionMatrix(((TransferFunction(3, s + 2, s),), (TransferFunction(p**4 - 3*p + 2, p + s, s),), (TransferFunction(-a - s, s**2 + s + 1, s),))), TransferFunctionMatrix(((TransferFunction(a + s, s**2 + s + 1, s),), (TransferFunction(p**4 - 3*p + 2, p + s, s),), (TransferFunction(-a + p, 9*s - 9, s),))))
>>> pprint(_, use_unicode=False)
[ 3 ] [ a + s ]
[ ----- ] [ ---------- ]
[ s + 2 ] [ 2 ]
[ ] [ s + s + 1 ]
[ 4 ] [ ]
[p - 3*p + 2] [ 4 ]
[------------] + [p - 3*p + 2]
[ p + s ] [------------]
[ ] [ p + s ]
[ -a - s ] [ ]
[ ---------- ] [ -a + p ]
[ 2 ] [ ------- ]
[ s + s + 1 ]{t} [ 9*s - 9 ]{t}
>>> -tfm_10 - tfm_8
MIMOParallel(TransferFunctionMatrix(((TransferFunction(-a - s, s**2 + s + 1, s),), (TransferFunction(-p**4 + 3*p - 2, p + s, s),), (TransferFunction(a - p, 9*s - 9, s),))), TransferFunctionMatrix(((TransferFunction(-3, s + 2, s),), (TransferFunction(-p**4 + 3*p - 2, p + s, s),), (TransferFunction(a + s, s**2 + s + 1, s),))))
>>> pprint(_, use_unicode=False)
[ -a - s ] [ -3 ]
[ ---------- ] [ ----- ]
[ 2 ] [ s + 2 ]
[ s + s + 1 ] [ ]
[ ] [ 4 ]
[ 4 ] [- p + 3*p - 2]
[- p + 3*p - 2] + [--------------]
[--------------] [ p + s ]
[ p + s ] [ ]
[ ] [ a + s ]
[ a - p ] [ ---------- ]
[ ------- ] [ 2 ]
[ 9*s - 9 ]{t} [ s + s + 1 ]{t}
>>> tfm_12 * tfm_8
MIMOSeries(TransferFunctionMatrix(((TransferFunction(3, s + 2, s),), (TransferFunction(p**4 - 3*p + 2, p + s, s),), (TransferFunction(-a - s, s**2 + s + 1, s),))), TransferFunctionMatrix(((TransferFunction(-a + p, 9*s - 9, s), TransferFunction(-a - s, s**2 + s + 1, s), TransferFunction(3, s + 2, s)), (TransferFunction(-p**4 + 3*p - 2, p + s, s), TransferFunction(a - p, 9*s - 9, s), TransferFunction(-3, s + 2, s)))))
>>> pprint(_, use_unicode=False)
[ 3 ]
[ ----- ]
[ -a + p -a - s 3 ] [ s + 2 ]
[ ------- ---------- -----] [ ]
[ 9*s - 9 2 s + 2] [ 4 ]
[ s + s + 1 ] [p - 3*p + 2]
[ ] *[------------]
[ 4 ] [ p + s ]
[- p + 3*p - 2 a - p -3 ] [ ]
[-------------- ------- -----] [ -a - s ]
[ p + s 9*s - 9 s + 2]{t} [ ---------- ]
[ 2 ]
[ s + s + 1 ]{t}
>>> tfm_12 * tfm_8 * tfm_9
MIMOSeries(TransferFunctionMatrix(((TransferFunction(-3, s + 2, s),),)), TransferFunctionMatrix(((TransferFunction(3, s + 2, s),), (TransferFunction(p**4 - 3*p + 2, p + s, s),), (TransferFunction(-a - s, s**2 + s + 1, s),))), TransferFunctionMatrix(((TransferFunction(-a + p, 9*s - 9, s), TransferFunction(-a - s, s**2 + s + 1, s), TransferFunction(3, s + 2, s)), (TransferFunction(-p**4 + 3*p - 2, p + s, s), TransferFunction(a - p, 9*s - 9, s), TransferFunction(-3, s + 2, s)))))
>>> pprint(_, use_unicode=False)
[ 3 ]
[ ----- ]
[ -a + p -a - s 3 ] [ s + 2 ]
[ ------- ---------- -----] [ ]
[ 9*s - 9 2 s + 2] [ 4 ]
[ s + s + 1 ] [p - 3*p + 2] [ -3 ]
[ ] *[------------] *[-----]
[ 4 ] [ p + s ] [s + 2]{t}
[- p + 3*p - 2 a - p -3 ] [ ]
[-------------- ------- -----] [ -a - s ]
[ p + s 9*s - 9 s + 2]{t} [ ---------- ]
[ 2 ]
[ s + s + 1 ]{t}
>>> tfm_10 + tfm_8*tfm_9
MIMOParallel(TransferFunctionMatrix(((TransferFunction(a + s, s**2 + s + 1, s),), (TransferFunction(p**4 - 3*p + 2, p + s, s),), (TransferFunction(-a + p, 9*s - 9, s),))), MIMOSeries(TransferFunctionMatrix(((TransferFunction(-3, s + 2, s),),)), TransferFunctionMatrix(((TransferFunction(3, s + 2, s),), (TransferFunction(p**4 - 3*p + 2, p + s, s),), (TransferFunction(-a - s, s**2 + s + 1, s),)))))
>>> pprint(_, use_unicode=False)
[ a + s ] [ 3 ]
[ ---------- ] [ ----- ]
[ 2 ] [ s + 2 ]
[ s + s + 1 ] [ ]
[ ] [ 4 ]
[ 4 ] [p - 3*p + 2] [ -3 ]
[p - 3*p + 2] + [------------] *[-----]
[------------] [ p + s ] [s + 2]{t}
[ p + s ] [ ]
[ ] [ -a - s ]
[ -a + p ] [ ---------- ]
[ ------- ] [ 2 ]
[ 9*s - 9 ]{t} [ s + s + 1 ]{t}
These unevaluated ``Series`` or ``Parallel`` objects can convert into the
resultant transfer function matrix using ``.doit()`` method or by
``.rewrite(TransferFunctionMatrix)``.
>>> (-tfm_8 + tfm_10 + tfm_8*tfm_9).doit()
TransferFunctionMatrix(((TransferFunction((a + s)*(s + 2)**3 - 3*(s + 2)**2*(s**2 + s + 1) - 9*(s + 2)*(s**2 + s + 1), (s + 2)**3*(s**2 + s + 1), s),), (TransferFunction((p + s)*(-3*p**4 + 9*p - 6), (p + s)**2*(s + 2), s),), (TransferFunction((-a + p)*(s + 2)*(s**2 + s + 1)**2 + (a + s)*(s + 2)*(9*s - 9)*(s**2 + s + 1) + (3*a + 3*s)*(9*s - 9)*(s**2 + s + 1), (s + 2)*(9*s - 9)*(s**2 + s + 1)**2, s),)))
>>> (-tfm_12 * -tfm_8 * -tfm_9).rewrite(TransferFunctionMatrix)
TransferFunctionMatrix(((TransferFunction(3*(-3*a + 3*p)*(p + s)*(s + 2)*(s**2 + s + 1)**2 + 3*(-3*a - 3*s)*(p + s)*(s + 2)*(9*s - 9)*(s**2 + s + 1) + 3*(a + s)*(s + 2)**2*(9*s - 9)*(-p**4 + 3*p - 2)*(s**2 + s + 1), (p + s)*(s + 2)**3*(9*s - 9)*(s**2 + s + 1)**2, s),), (TransferFunction(3*(-a + p)*(p + s)*(s + 2)**2*(-p**4 + 3*p - 2)*(s**2 + s + 1) + 3*(3*a + 3*s)*(p + s)**2*(s + 2)*(9*s - 9) + 3*(p + s)*(s + 2)*(9*s - 9)*(-3*p**4 + 9*p - 6)*(s**2 + s + 1), (p + s)**2*(s + 2)**3*(9*s - 9)*(s**2 + s + 1), s),)))
See Also
========
TransferFunction, MIMOSeries, MIMOParallel, Feedback
"""
def __new__(cls, arg):
expr_mat_arg = []
try:
var = arg[0][0].var
except TypeError:
raise ValueError(filldedent("""
`arg` param in TransferFunctionMatrix should
strictly be a nested list containing TransferFunction
objects."""))
for row in arg:
temp = []
for element in row:
if not isinstance(element, SISOLinearTimeInvariant):
raise TypeError(filldedent("""
Each element is expected to be of
type `SISOLinearTimeInvariant`."""))
if var != element.var:
raise ValueError(filldedent("""
Conflicting value(s) found for `var`. All TransferFunction
instances in TransferFunctionMatrix should use the same
complex variable in Laplace domain."""))
temp.append(element.to_expr())
expr_mat_arg.append(temp)
if isinstance(arg, (tuple, list, Tuple)):
# Making nested Tuple (sympy.core.containers.Tuple) from nested list or nested Python tuple
arg = Tuple(*(Tuple(*r, sympify=False) for r in arg), sympify=False)
obj = super(TransferFunctionMatrix, cls).__new__(cls, arg)
obj._expr_mat = ImmutableMatrix(expr_mat_arg)
return obj
@classmethod
def from_Matrix(cls, matrix, var):
"""
Creates a new ``TransferFunctionMatrix`` efficiently from a SymPy Matrix of ``Expr`` objects.
Parameters
==========
matrix : ``ImmutableMatrix`` having ``Expr``/``Number`` elements.
var : Symbol
Complex variable of the Laplace transform which will be used by the
all the ``TransferFunction`` objects in the ``TransferFunctionMatrix``.
Examples
========
>>> from sympy.abc import s
>>> from sympy.physics.control.lti import TransferFunctionMatrix
>>> from sympy import Matrix, pprint
>>> M = Matrix([[s, 1/s], [1/(s+1), s]])
>>> M_tf = TransferFunctionMatrix.from_Matrix(M, s)
>>> pprint(M_tf, use_unicode=False)
[ s 1]
[ - -]
[ 1 s]
[ ]
[ 1 s]
[----- -]
[s + 1 1]{t}
>>> M_tf.elem_poles()
[[[], [0]], [[-1], []]]
>>> M_tf.elem_zeros()
[[[0], []], [[], [0]]]
"""
return _to_TFM(matrix, var)
@property
def var(self):
"""
Returns the complex variable used by all the transfer functions or
``Series``/``Parallel`` objects in a transfer function matrix.
Examples
========
>>> from sympy.abc import p, s
>>> from sympy.physics.control.lti import TransferFunction, TransferFunctionMatrix, Series, Parallel
>>> G1 = TransferFunction(p**2 + 2*p + 4, p - 6, p)
>>> G2 = TransferFunction(p, 4 - p, p)
>>> G3 = TransferFunction(0, p**4 - 1, p)
>>> G4 = TransferFunction(s + 1, s**2 + s + 1, s)
>>> S1 = Series(G1, G2)
>>> S2 = Series(-G3, Parallel(G2, -G1))
>>> tfm1 = TransferFunctionMatrix([[G1], [G2], [G3]])
>>> tfm1.var
p
>>> tfm2 = TransferFunctionMatrix([[-S1, -S2], [S1, S2]])
>>> tfm2.var
p
>>> tfm3 = TransferFunctionMatrix([[G4]])
>>> tfm3.var
s
"""
return self.args[0][0][0].var
@property
def num_inputs(self):
"""
Returns the number of inputs of the system.
Examples
========
>>> from sympy.abc import s, p
>>> from sympy.physics.control.lti import TransferFunction, TransferFunctionMatrix
>>> G1 = TransferFunction(s + 3, s**2 - 3, s)
>>> G2 = TransferFunction(4, s**2, s)
>>> G3 = TransferFunction(p**2 + s**2, p - 3, s)
>>> tfm_1 = TransferFunctionMatrix([[G2, -G1, G3], [-G2, -G1, -G3]])
>>> tfm_1.num_inputs
3
See Also
========
num_outputs
"""
return self._expr_mat.shape[1]
@property
def num_outputs(self):
"""
Returns the number of outputs of the system.
Examples
========
>>> from sympy.abc import s
>>> from sympy.physics.control.lti import TransferFunctionMatrix
>>> from sympy import Matrix
>>> M_1 = Matrix([[s], [1/s]])
>>> TFM = TransferFunctionMatrix.from_Matrix(M_1, s)
>>> print(TFM)
TransferFunctionMatrix(((TransferFunction(s, 1, s),), (TransferFunction(1, s, s),)))
>>> TFM.num_outputs
2
See Also
========
num_inputs
"""
return self._expr_mat.shape[0]
@property
def shape(self):
"""
Returns the shape of the transfer function matrix, that is, ``(# of outputs, # of inputs)``.
Examples
========
>>> from sympy.abc import s, p
>>> from sympy.physics.control.lti import TransferFunction, TransferFunctionMatrix
>>> tf1 = TransferFunction(p**2 - 1, s**4 + s**3 - p, p)
>>> tf2 = TransferFunction(1 - p, p**2 - 3*p + 7, p)
>>> tf3 = TransferFunction(3, 4, p)
>>> tfm1 = TransferFunctionMatrix([[tf1, -tf2]])
>>> tfm1.shape
(1, 2)
>>> tfm2 = TransferFunctionMatrix([[-tf2, tf3], [tf1, -tf1]])
>>> tfm2.shape
(2, 2)
"""
return self._expr_mat.shape
def __neg__(self):
neg = -self._expr_mat
return _to_TFM(neg, self.var)
@_check_other_MIMO
def __add__(self, other):
if not isinstance(other, MIMOParallel):
return MIMOParallel(self, other)
other_arg_list = list(other.args)
return MIMOParallel(self, *other_arg_list)
@_check_other_MIMO
def __sub__(self, other):
return self + (-other)
@_check_other_MIMO
def __mul__(self, other):
if not isinstance(other, MIMOSeries):
return MIMOSeries(other, self)
other_arg_list = list(other.args)
return MIMOSeries(*other_arg_list, self)
def __getitem__(self, key):
trunc = self._expr_mat.__getitem__(key)
if isinstance(trunc, ImmutableMatrix):
return _to_TFM(trunc, self.var)
return TransferFunction.from_rational_expression(trunc, self.var)
def transpose(self):
"""Returns the transpose of the ``TransferFunctionMatrix`` (switched input and output layers)."""
transposed_mat = self._expr_mat.transpose()
return _to_TFM(transposed_mat, self.var)
def elem_poles(self):
"""
Returns the poles of each element of the ``TransferFunctionMatrix``.
.. note::
Actual poles of a MIMO system are NOT the poles of individual elements.
Examples
========
>>> from sympy.abc import s
>>> from sympy.physics.control.lti import TransferFunction, TransferFunctionMatrix
>>> tf_1 = TransferFunction(3, (s + 1), s)
>>> tf_2 = TransferFunction(s + 6, (s + 1)*(s + 2), s)
>>> tf_3 = TransferFunction(s + 3, s**2 + 3*s + 2, s)
>>> tf_4 = TransferFunction(s + 2, s**2 + 5*s - 10, s)
>>> tfm_1 = TransferFunctionMatrix([[tf_1, tf_2], [tf_3, tf_4]])
>>> tfm_1
TransferFunctionMatrix(((TransferFunction(3, s + 1, s), TransferFunction(s + 6, (s + 1)*(s + 2), s)), (TransferFunction(s + 3, s**2 + 3*s + 2, s), TransferFunction(s + 2, s**2 + 5*s - 10, s))))
>>> tfm_1.elem_poles()
[[[-1], [-2, -1]], [[-2, -1], [-5/2 + sqrt(65)/2, -sqrt(65)/2 - 5/2]]]
See Also
========
elem_zeros
"""
return [[element.poles() for element in row] for row in self.doit().args[0]]
def elem_zeros(self):
"""
Returns the zeros of each element of the ``TransferFunctionMatrix``.
.. note::
Actual zeros of a MIMO system are NOT the zeros of individual elements.
Examples
========
>>> from sympy.abc import s
>>> from sympy.physics.control.lti import TransferFunction, TransferFunctionMatrix
>>> tf_1 = TransferFunction(3, (s + 1), s)
>>> tf_2 = TransferFunction(s + 6, (s + 1)*(s + 2), s)
>>> tf_3 = TransferFunction(s + 3, s**2 + 3*s + 2, s)
>>> tf_4 = TransferFunction(s**2 - 9*s + 20, s**2 + 5*s - 10, s)
>>> tfm_1 = TransferFunctionMatrix([[tf_1, tf_2], [tf_3, tf_4]])
>>> tfm_1
TransferFunctionMatrix(((TransferFunction(3, s + 1, s), TransferFunction(s + 6, (s + 1)*(s + 2), s)), (TransferFunction(s + 3, s**2 + 3*s + 2, s), TransferFunction(s**2 - 9*s + 20, s**2 + 5*s - 10, s))))
>>> tfm_1.elem_zeros()
[[[], [-6]], [[-3], [4, 5]]]
See Also
========
elem_poles
"""
return [[element.zeros() for element in row] for row in self.doit().args[0]]
def eval_frequency(self, other):
"""
Evaluates system response of each transfer function in the ``TransferFunctionMatrix`` at any point in the real or complex plane.
Examples
========
>>> from sympy.abc import s
>>> from sympy.physics.control.lti import TransferFunction, TransferFunctionMatrix
>>> from sympy import I
>>> tf_1 = TransferFunction(3, (s + 1), s)
>>> tf_2 = TransferFunction(s + 6, (s + 1)*(s + 2), s)
>>> tf_3 = TransferFunction(s + 3, s**2 + 3*s + 2, s)
>>> tf_4 = TransferFunction(s**2 - 9*s + 20, s**2 + 5*s - 10, s)
>>> tfm_1 = TransferFunctionMatrix([[tf_1, tf_2], [tf_3, tf_4]])
>>> tfm_1
TransferFunctionMatrix(((TransferFunction(3, s + 1, s), TransferFunction(s + 6, (s + 1)*(s + 2), s)), (TransferFunction(s + 3, s**2 + 3*s + 2, s), TransferFunction(s**2 - 9*s + 20, s**2 + 5*s - 10, s))))
>>> tfm_1.eval_frequency(2)
Matrix([
[ 1, 2/3],
[5/12, 3/2]])
>>> tfm_1.eval_frequency(I*2)
Matrix([
[ 3/5 - 6*I/5, -I],
[3/20 - 11*I/20, -101/74 + 23*I/74]])
"""
mat = self._expr_mat.subs(self.var, other)
return mat.expand()
def _flat(self):
"""Returns flattened list of args in TransferFunctionMatrix"""
return [elem for tup in self.args[0] for elem in tup]
def _eval_evalf(self, prec):
"""Calls evalf() on each transfer function in the transfer function matrix"""
dps = prec_to_dps(prec)
mat = self._expr_mat.applyfunc(lambda a: a.evalf(n=dps))
return _to_TFM(mat, self.var)
def _eval_simplify(self, **kwargs):
"""Simplifies the transfer function matrix"""
simp_mat = self._expr_mat.applyfunc(lambda a: cancel(a, expand=False))
return _to_TFM(simp_mat, self.var)
def expand(self, **hints):
"""Expands the transfer function matrix"""
expand_mat = self._expr_mat.expand(**hints)
return _to_TFM(expand_mat, self.var)
class StateSpace(LinearTimeInvariant):
r"""
State space model (ssm) of a linear, time invariant control system.
Represents the standard state-space model with A, B, C, D as state-space matrices.
This makes the linear control system:
(1) x'(t) = A * x(t) + B * u(t); x in R^n , u in R^k
(2) y(t) = C * x(t) + D * u(t); y in R^m
where u(t) is any input signal, y(t) the corresponding output, and x(t) the system's state.
Parameters
==========
A : Matrix
The State matrix of the state space model.
B : Matrix
The Input-to-State matrix of the state space model.
C : Matrix
The State-to-Output matrix of the state space model.
D : Matrix
The Feedthrough matrix of the state space model.
Examples
========
>>> from sympy import Matrix
>>> from sympy.physics.control import StateSpace
The easiest way to create a StateSpaceModel is via four matrices:
>>> A = Matrix([[1, 2], [1, 0]])
>>> B = Matrix([1, 1])
>>> C = Matrix([[0, 1]])
>>> D = Matrix([0])
>>> StateSpace(A, B, C, D)
StateSpace(Matrix([
[1, 2],
[1, 0]]), Matrix([
[1],
[1]]), Matrix([[0, 1]]), Matrix([[0]]))
One can use less matrices. The rest will be filled with a minimum of zeros:
>>> StateSpace(A, B)
StateSpace(Matrix([
[1, 2],
[1, 0]]), Matrix([
[1],
[1]]), Matrix([[0, 0]]), Matrix([[0]]))
See Also
========
TransferFunction, TransferFunctionMatrix
References
==========
.. [1] https://en.wikipedia.org/wiki/State-space_representation
.. [2] https://in.mathworks.com/help/control/ref/ss.html
"""
def __new__(cls, A=None, B=None, C=None, D=None):
if A is None:
A = zeros(1)
if B is None:
B = zeros(A.rows, 1)
if C is None:
C = zeros(1, A.cols)
if D is None:
D = zeros(C.rows, B.cols)
A = _sympify(A)
B = _sympify(B)
C = _sympify(C)
D = _sympify(D)
if (isinstance(A, ImmutableDenseMatrix) and isinstance(B, ImmutableDenseMatrix) and
isinstance(C, ImmutableDenseMatrix) and isinstance(D, ImmutableDenseMatrix)):
# Check State Matrix is square
if A.rows != A.cols:
raise ShapeError("Matrix A must be a square matrix.")
# Check State and Input matrices have same rows
if A.rows != B.rows:
raise ShapeError("Matrices A and B must have the same number of rows.")
# Check Ouput and Feedthrough matrices have same rows
if C.rows != D.rows:
raise ShapeError("Matrices C and D must have the same number of rows.")
# Check State and Ouput matrices have same columns
if A.cols != C.cols:
raise ShapeError("Matrices A and C must have the same number of columns.")
# Check Input and Feedthrough matrices have same columns
if B.cols != D.cols:
raise ShapeError("Matrices B and D must have the same number of columns.")
obj = super(StateSpace, cls).__new__(cls, A, B, C, D)
obj._A = A
obj._B = B
obj._C = C
obj._D = D
# Determine if the system is SISO or MIMO
num_outputs = D.rows
num_inputs = D.cols
if num_inputs == 1 and num_outputs == 1:
obj._is_SISO = True
obj._clstype = SISOLinearTimeInvariant
else:
obj._is_SISO = False
obj._clstype = MIMOLinearTimeInvariant
return obj
else:
raise TypeError("A, B, C and D inputs must all be sympy Matrices.")
@property
def state_matrix(self):
"""
Returns the state matrix of the model.
Examples
========
>>> from sympy import Matrix
>>> from sympy.physics.control import StateSpace
>>> A = Matrix([[1, 2], [1, 0]])
>>> B = Matrix([1, 1])
>>> C = Matrix([[0, 1]])
>>> D = Matrix([0])
>>> ss = StateSpace(A, B, C, D)
>>> ss.state_matrix
Matrix([
[1, 2],
[1, 0]])
"""
return self._A
@property
def input_matrix(self):
"""
Returns the input matrix of the model.
Examples
========
>>> from sympy import Matrix
>>> from sympy.physics.control import StateSpace
>>> A = Matrix([[1, 2], [1, 0]])
>>> B = Matrix([1, 1])
>>> C = Matrix([[0, 1]])
>>> D = Matrix([0])
>>> ss = StateSpace(A, B, C, D)
>>> ss.input_matrix
Matrix([
[1],
[1]])
"""
return self._B
@property
def output_matrix(self):
"""
Returns the output matrix of the model.
Examples
========
>>> from sympy import Matrix
>>> from sympy.physics.control import StateSpace
>>> A = Matrix([[1, 2], [1, 0]])
>>> B = Matrix([1, 1])
>>> C = Matrix([[0, 1]])
>>> D = Matrix([0])
>>> ss = StateSpace(A, B, C, D)
>>> ss.output_matrix
Matrix([[0, 1]])
"""
return self._C
@property
def feedforward_matrix(self):
"""
Returns the feedforward matrix of the model.
Examples
========
>>> from sympy import Matrix
>>> from sympy.physics.control import StateSpace
>>> A = Matrix([[1, 2], [1, 0]])
>>> B = Matrix([1, 1])
>>> C = Matrix([[0, 1]])
>>> D = Matrix([0])
>>> ss = StateSpace(A, B, C, D)
>>> ss.feedforward_matrix
Matrix([[0]])
"""
return self._D
@property
def num_states(self):
"""
Returns the number of states of the model.
Examples
========
>>> from sympy import Matrix
>>> from sympy.physics.control import StateSpace
>>> A = Matrix([[1, 2], [1, 0]])
>>> B = Matrix([1, 1])
>>> C = Matrix([[0, 1]])
>>> D = Matrix([0])
>>> ss = StateSpace(A, B, C, D)
>>> ss.num_states
2
"""
return self._A.rows
@property
def num_inputs(self):
"""
Returns the number of inputs of the model.
Examples
========
>>> from sympy import Matrix
>>> from sympy.physics.control import StateSpace
>>> A = Matrix([[1, 2], [1, 0]])
>>> B = Matrix([1, 1])
>>> C = Matrix([[0, 1]])
>>> D = Matrix([0])
>>> ss = StateSpace(A, B, C, D)
>>> ss.num_inputs
1
"""
return self._D.cols
@property
def num_outputs(self):
"""
Returns the number of outputs of the model.
Examples
========
>>> from sympy import Matrix
>>> from sympy.physics.control import StateSpace
>>> A = Matrix([[1, 2], [1, 0]])
>>> B = Matrix([1, 1])
>>> C = Matrix([[0, 1]])
>>> D = Matrix([0])
>>> ss = StateSpace(A, B, C, D)
>>> ss.num_outputs
1
"""
return self._D.rows
def _eval_evalf(self, prec):
"""
Returns state space model where numerical expressions are evaluated into floating point numbers.
"""
dps = prec_to_dps(prec)
return StateSpace(
self._A.evalf(n = dps),
self._B.evalf(n = dps),
self._C.evalf(n = dps),
self._D.evalf(n = dps))
def _eval_rewrite_as_TransferFunction(self, *args):
"""
Returns the equivalent Transfer Function of the state space model.
Examples
========
>>> from sympy import Matrix
>>> from sympy.physics.control import TransferFunction, StateSpace
>>> A = Matrix([[-5, -1], [3, -1]])
>>> B = Matrix([2, 5])
>>> C = Matrix([[1, 2]])
>>> D = Matrix([0])
>>> ss = StateSpace(A, B, C, D)
>>> ss.rewrite(TransferFunction)
[[TransferFunction(12*s + 59, s**2 + 6*s + 8, s)]]
"""
s = Symbol('s')
n = self._A.shape[0]
I = eye(n)
G = self._C*(s*I - self._A).solve(self._B) + self._D
G = G.simplify()
to_tf = lambda expr: TransferFunction.from_rational_expression(expr, s)
tf_mat = [[to_tf(expr) for expr in sublist] for sublist in G.tolist()]
return tf_mat
def __add__(self, other):
"""
Add two State Space systems (parallel connection).
Examples
========
>>> from sympy import Matrix
>>> from sympy.physics.control import StateSpace
>>> A1 = Matrix([[1]])
>>> B1 = Matrix([[2]])
>>> C1 = Matrix([[-1]])
>>> D1 = Matrix([[-2]])
>>> A2 = Matrix([[-1]])
>>> B2 = Matrix([[-2]])
>>> C2 = Matrix([[1]])
>>> D2 = Matrix([[2]])
>>> ss1 = StateSpace(A1, B1, C1, D1)
>>> ss2 = StateSpace(A2, B2, C2, D2)
>>> ss1 + ss2
StateSpace(Matrix([
[1, 0],
[0, -1]]), Matrix([
[ 2],
[-2]]), Matrix([[-1, 1]]), Matrix([[0]]))
"""
# Check for scalars
if isinstance(other, (int, float, complex, Symbol)):
A = self._A
B = self._B
C = self._C
D = self._D.applyfunc(lambda element: element + other)
else:
# Check nature of system
if not isinstance(other, StateSpace):
raise ValueError("Addition is only supported for 2 State Space models.")
# Check dimensions of system
elif ((self.num_inputs != other.num_inputs) or (self.num_outputs != other.num_outputs)):
raise ShapeError("Systems with incompatible inputs and outputs cannot be added.")
m1 = (self._A).row_join(zeros(self._A.shape[0], other._A.shape[-1]))
m2 = zeros(other._A.shape[0], self._A.shape[-1]).row_join(other._A)
A = m1.col_join(m2)
B = self._B.col_join(other._B)
C = self._C.row_join(other._C)
D = self._D + other._D
return StateSpace(A, B, C, D)
def __radd__(self, other):
"""
Right add two State Space systems.
Examples
========
>>> from sympy.physics.control import StateSpace
>>> s = StateSpace()
>>> 5 + s
StateSpace(Matrix([[0]]), Matrix([[0]]), Matrix([[0]]), Matrix([[5]]))
"""
return self + other
def __sub__(self, other):
"""
Subtract two State Space systems.
Examples
========
>>> from sympy import Matrix
>>> from sympy.physics.control import StateSpace
>>> A1 = Matrix([[1]])
>>> B1 = Matrix([[2]])
>>> C1 = Matrix([[-1]])
>>> D1 = Matrix([[-2]])
>>> A2 = Matrix([[-1]])
>>> B2 = Matrix([[-2]])
>>> C2 = Matrix([[1]])
>>> D2 = Matrix([[2]])
>>> ss1 = StateSpace(A1, B1, C1, D1)
>>> ss2 = StateSpace(A2, B2, C2, D2)
>>> ss1 - ss2
StateSpace(Matrix([
[1, 0],
[0, -1]]), Matrix([
[ 2],
[-2]]), Matrix([[-1, -1]]), Matrix([[-4]]))
"""
return self + (-other)
def __rsub__(self, other):
"""
Right subtract two tate Space systems.
Examples
========
>>> from sympy.physics.control import StateSpace
>>> s = StateSpace()
>>> 5 - s
StateSpace(Matrix([[0]]), Matrix([[0]]), Matrix([[0]]), Matrix([[5]]))
"""
return other + (-self)
def __neg__(self):
"""
Returns the negation of the state space model.
Examples
========
>>> from sympy import Matrix
>>> from sympy.physics.control import StateSpace
>>> A = Matrix([[-5, -1], [3, -1]])
>>> B = Matrix([2, 5])
>>> C = Matrix([[1, 2]])
>>> D = Matrix([0])
>>> ss = StateSpace(A, B, C, D)
>>> -ss
StateSpace(Matrix([
[-5, -1],
[ 3, -1]]), Matrix([
[2],
[5]]), Matrix([[-1, -2]]), Matrix([[0]]))
"""
return StateSpace(self._A, self._B, -self._C, -self._D)
def __mul__(self, other):
"""
Multiplication of two State Space systems (serial connection).
Examples
========
>>> from sympy import Matrix
>>> from sympy.physics.control import StateSpace
>>> A = Matrix([[-5, -1], [3, -1]])
>>> B = Matrix([2, 5])
>>> C = Matrix([[1, 2]])
>>> D = Matrix([0])
>>> ss = StateSpace(A, B, C, D)
>>> ss*5
StateSpace(Matrix([
[-5, -1],
[ 3, -1]]), Matrix([
[2],
[5]]), Matrix([[5, 10]]), Matrix([[0]]))
"""
# Check for scalars
if isinstance(other, (int, float, complex, Symbol)):
A = self._A
B = self._B
C = self._C.applyfunc(lambda element: element*other)
D = self._D.applyfunc(lambda element: element*other)
else:
# Check nature of system
if not isinstance(other, StateSpace):
raise ValueError("Multiplication is only supported for 2 State Space models.")
# Check dimensions of system
elif self.num_inputs != other.num_outputs:
raise ShapeError("Systems with incompatible inputs and outputs cannot be multiplied.")
m1 = (other._A).row_join(zeros(other._A.shape[0], self._A.shape[1]))
m2 = (self._B * other._C).row_join(self._A)
A = m1.col_join(m2)
B = (other._B).col_join(self._B * other._D)
C = (self._D * other._C).row_join(self._C)
D = self._D * other._D
return StateSpace(A, B, C, D)
def __rmul__(self, other):
"""
Right multiply two tate Space systems.
Examples
========
>>> from sympy import Matrix
>>> from sympy.physics.control import StateSpace
>>> A = Matrix([[-5, -1], [3, -1]])
>>> B = Matrix([2, 5])
>>> C = Matrix([[1, 2]])
>>> D = Matrix([0])
>>> ss = StateSpace(A, B, C, D)
>>> 5*ss
StateSpace(Matrix([
[-5, -1],
[ 3, -1]]), Matrix([
[10],
[25]]), Matrix([[1, 2]]), Matrix([[0]]))
"""
if isinstance(other, (int, float, complex, Symbol)):
A = self._A
C = self._C
B = self._B.applyfunc(lambda element: element*other)
D = self._D.applyfunc(lambda element: element*other)
return StateSpace(A, B, C, D)
else:
return self*other
def __repr__(self):
A_str = self._A.__repr__()
B_str = self._B.__repr__()
C_str = self._C.__repr__()
D_str = self._D.__repr__()
return f"StateSpace(\n{A_str},\n\n{B_str},\n\n{C_str},\n\n{D_str})"
def append(self, other):
"""
Returns the first model appended with the second model. The order is preserved.
Examples
========
>>> from sympy import Matrix
>>> from sympy.physics.control import StateSpace
>>> A1 = Matrix([[1]])
>>> B1 = Matrix([[2]])
>>> C1 = Matrix([[-1]])
>>> D1 = Matrix([[-2]])
>>> A2 = Matrix([[-1]])
>>> B2 = Matrix([[-2]])
>>> C2 = Matrix([[1]])
>>> D2 = Matrix([[2]])
>>> ss1 = StateSpace(A1, B1, C1, D1)
>>> ss2 = StateSpace(A2, B2, C2, D2)
>>> ss1.append(ss2)
StateSpace(Matrix([
[1, 0],
[0, -1]]), Matrix([
[2, 0],
[0, -2]]), Matrix([
[-1, 0],
[ 0, 1]]), Matrix([
[-2, 0],
[ 0, 2]]))
"""
n = self.num_states + other.num_states
m = self.num_inputs + other.num_inputs
p = self.num_outputs + other.num_outputs
A = zeros(n, n)
B = zeros(n, m)
C = zeros(p, n)
D = zeros(p, m)
A[:self.num_states, :self.num_states] = self._A
A[self.num_states:, self.num_states:] = other._A
B[:self.num_states, :self.num_inputs] = self._B
B[self.num_states:, self.num_inputs:] = other._B
C[:self.num_outputs, :self.num_states] = self._C
C[self.num_outputs:, self.num_states:] = other._C
D[:self.num_outputs, :self.num_inputs] = self._D
D[self.num_outputs:, self.num_inputs:] = other._D
return StateSpace(A, B, C, D)
def observability_matrix(self):
"""
Returns the observability matrix of the state space model:
[C, C * A^1, C * A^2, .. , C * A^(n-1)]; A in R^(n x n), C in R^(m x k)
Examples
========
>>> from sympy import Matrix
>>> from sympy.physics.control import StateSpace
>>> A = Matrix([[-1.5, -2], [1, 0]])
>>> B = Matrix([0.5, 0])
>>> C = Matrix([[0, 1]])
>>> D = Matrix([1])
>>> ss = StateSpace(A, B, C, D)
>>> ob = ss.observability_matrix()
>>> ob
Matrix([
[0, 1],
[1, 0]])
References
==========
.. [1] https://in.mathworks.com/help/control/ref/statespacemodel.obsv.html
"""
n = self.num_states
ob = self._C
for i in range(1,n):
ob = ob.col_join(self._C * self._A**i)
return ob
def observable_subspace(self):
"""
Returns the observable subspace of the state space model.
Examples
========
>>> from sympy import Matrix
>>> from sympy.physics.control import StateSpace
>>> A = Matrix([[-1.5, -2], [1, 0]])
>>> B = Matrix([0.5, 0])
>>> C = Matrix([[0, 1]])
>>> D = Matrix([1])
>>> ss = StateSpace(A, B, C, D)
>>> ob_subspace = ss.observable_subspace()
>>> ob_subspace
[Matrix([
[0],
[1]]), Matrix([
[1],
[0]])]
"""
return self.observability_matrix().columnspace()
def is_observable(self):
"""
Returns if the state space model is observable.
Examples
========
>>> from sympy import Matrix
>>> from sympy.physics.control import StateSpace
>>> A = Matrix([[-1.5, -2], [1, 0]])
>>> B = Matrix([0.5, 0])
>>> C = Matrix([[0, 1]])
>>> D = Matrix([1])
>>> ss = StateSpace(A, B, C, D)
>>> ss.is_observable()
True
"""
return self.observability_matrix().rank() == self.num_states
def controllability_matrix(self):
"""
Returns the controllability matrix of the system:
[B, A * B, A^2 * B, .. , A^(n-1) * B]; A in R^(n x n), B in R^(n x m)
Examples
========
>>> from sympy import Matrix
>>> from sympy.physics.control import StateSpace
>>> A = Matrix([[-1.5, -2], [1, 0]])
>>> B = Matrix([0.5, 0])
>>> C = Matrix([[0, 1]])
>>> D = Matrix([1])
>>> ss = StateSpace(A, B, C, D)
>>> ss.controllability_matrix()
Matrix([
[0.5, -0.75],
[ 0, 0.5]])
References
==========
.. [1] https://in.mathworks.com/help/control/ref/statespacemodel.ctrb.html
"""
co = self._B
n = self._A.shape[0]
for i in range(1, n):
co = co.row_join(((self._A)**i) * self._B)
return co
def controllable_subspace(self):
"""
Returns the controllable subspace of the state space model.
Examples
========
>>> from sympy import Matrix
>>> from sympy.physics.control import StateSpace
>>> A = Matrix([[-1.5, -2], [1, 0]])
>>> B = Matrix([0.5, 0])
>>> C = Matrix([[0, 1]])
>>> D = Matrix([1])
>>> ss = StateSpace(A, B, C, D)
>>> co_subspace = ss.controllable_subspace()
>>> co_subspace
[Matrix([
[0.5],
[ 0]]), Matrix([
[-0.75],
[ 0.5]])]
"""
return self.controllability_matrix().columnspace()
def is_controllable(self):
"""
Returns if the state space model is controllable.
Examples
========
>>> from sympy import Matrix
>>> from sympy.physics.control import StateSpace
>>> A = Matrix([[-1.5, -2], [1, 0]])
>>> B = Matrix([0.5, 0])
>>> C = Matrix([[0, 1]])
>>> D = Matrix([1])
>>> ss = StateSpace(A, B, C, D)
>>> ss.is_controllable()
True
"""
return self.controllability_matrix().rank() == self.num_states
PK ]ZZZ sympy/physics/hep/__init__.pyPK ]ZZZ�* �^ �^ # sympy/physics/hep/gamma_matrices.py"""
Module to handle gamma matrices expressed as tensor objects.
Examples
========
>>> from sympy.physics.hep.gamma_matrices import GammaMatrix as G, LorentzIndex
>>> from sympy.tensor.tensor import tensor_indices
>>> i = tensor_indices('i', LorentzIndex)
>>> G(i)
GammaMatrix(i)
Note that there is already an instance of GammaMatrixHead in four dimensions:
GammaMatrix, which is simply declare as
>>> from sympy.physics.hep.gamma_matrices import GammaMatrix
>>> from sympy.tensor.tensor import tensor_indices
>>> i = tensor_indices('i', LorentzIndex)
>>> GammaMatrix(i)
GammaMatrix(i)
To access the metric tensor
>>> LorentzIndex.metric
metric(LorentzIndex,LorentzIndex)
"""
from sympy.core.mul import Mul
from sympy.core.singleton import S
from sympy.matrices.dense import eye
from sympy.matrices.expressions.trace import trace
from sympy.tensor.tensor import TensorIndexType, TensorIndex,\
TensMul, TensAdd, tensor_mul, Tensor, TensorHead, TensorSymmetry
# DiracSpinorIndex = TensorIndexType('DiracSpinorIndex', dim=4, dummy_name="S")
LorentzIndex = TensorIndexType('LorentzIndex', dim=4, dummy_name="L")
GammaMatrix = TensorHead("GammaMatrix", [LorentzIndex],
TensorSymmetry.no_symmetry(1), comm=None)
def extract_type_tens(expression, component):
"""
Extract from a ``TensExpr`` all tensors with `component`.
Returns two tensor expressions:
* the first contains all ``Tensor`` of having `component`.
* the second contains all remaining.
"""
if isinstance(expression, Tensor):
sp = [expression]
elif isinstance(expression, TensMul):
sp = expression.args
else:
raise ValueError('wrong type')
# Collect all gamma matrices of the same dimension
new_expr = S.One
residual_expr = S.One
for i in sp:
if isinstance(i, Tensor) and i.component == component:
new_expr *= i
else:
residual_expr *= i
return new_expr, residual_expr
def simplify_gamma_expression(expression):
extracted_expr, residual_expr = extract_type_tens(expression, GammaMatrix)
res_expr = _simplify_single_line(extracted_expr)
return res_expr * residual_expr
def simplify_gpgp(ex, sort=True):
"""
simplify products ``G(i)*p(-i)*G(j)*p(-j) -> p(i)*p(-i)``
Examples
========
>>> from sympy.physics.hep.gamma_matrices import GammaMatrix as G, \
LorentzIndex, simplify_gpgp
>>> from sympy.tensor.tensor import tensor_indices, tensor_heads
>>> p, q = tensor_heads('p, q', [LorentzIndex])
>>> i0,i1,i2,i3,i4,i5 = tensor_indices('i0:6', LorentzIndex)
>>> ps = p(i0)*G(-i0)
>>> qs = q(i0)*G(-i0)
>>> simplify_gpgp(ps*qs*qs)
GammaMatrix(-L_0)*p(L_0)*q(L_1)*q(-L_1)
"""
def _simplify_gpgp(ex):
components = ex.components
a = []
comp_map = []
for i, comp in enumerate(components):
comp_map.extend([i]*comp.rank)
dum = [(i[0], i[1], comp_map[i[0]], comp_map[i[1]]) for i in ex.dum]
for i in range(len(components)):
if components[i] != GammaMatrix:
continue
for dx in dum:
if dx[2] == i:
p_pos1 = dx[3]
elif dx[3] == i:
p_pos1 = dx[2]
else:
continue
comp1 = components[p_pos1]
if comp1.comm == 0 and comp1.rank == 1:
a.append((i, p_pos1))
if not a:
return ex
elim = set()
tv = []
hit = True
coeff = S.One
ta = None
while hit:
hit = False
for i, ai in enumerate(a[:-1]):
if ai[0] in elim:
continue
if ai[0] != a[i + 1][0] - 1:
continue
if components[ai[1]] != components[a[i + 1][1]]:
continue
elim.add(ai[0])
elim.add(ai[1])
elim.add(a[i + 1][0])
elim.add(a[i + 1][1])
if not ta:
ta = ex.split()
mu = TensorIndex('mu', LorentzIndex)
hit = True
if i == 0:
coeff = ex.coeff
tx = components[ai[1]](mu)*components[ai[1]](-mu)
if len(a) == 2:
tx *= 4 # eye(4)
tv.append(tx)
break
if tv:
a = [x for j, x in enumerate(ta) if j not in elim]
a.extend(tv)
t = tensor_mul(*a)*coeff
# t = t.replace(lambda x: x.is_Matrix, lambda x: 1)
return t
else:
return ex
if sort:
ex = ex.sorted_components()
# this would be better off with pattern matching
while 1:
t = _simplify_gpgp(ex)
if t != ex:
ex = t
else:
return t
def gamma_trace(t):
"""
trace of a single line of gamma matrices
Examples
========
>>> from sympy.physics.hep.gamma_matrices import GammaMatrix as G, \
gamma_trace, LorentzIndex
>>> from sympy.tensor.tensor import tensor_indices, tensor_heads
>>> p, q = tensor_heads('p, q', [LorentzIndex])
>>> i0,i1,i2,i3,i4,i5 = tensor_indices('i0:6', LorentzIndex)
>>> ps = p(i0)*G(-i0)
>>> qs = q(i0)*G(-i0)
>>> gamma_trace(G(i0)*G(i1))
4*metric(i0, i1)
>>> gamma_trace(ps*ps) - 4*p(i0)*p(-i0)
0
>>> gamma_trace(ps*qs + ps*ps) - 4*p(i0)*p(-i0) - 4*p(i0)*q(-i0)
0
"""
if isinstance(t, TensAdd):
res = TensAdd(*[gamma_trace(x) for x in t.args])
return res
t = _simplify_single_line(t)
res = _trace_single_line(t)
return res
def _simplify_single_line(expression):
"""
Simplify single-line product of gamma matrices.
Examples
========
>>> from sympy.physics.hep.gamma_matrices import GammaMatrix as G, \
LorentzIndex, _simplify_single_line
>>> from sympy.tensor.tensor import tensor_indices, TensorHead
>>> p = TensorHead('p', [LorentzIndex])
>>> i0,i1 = tensor_indices('i0:2', LorentzIndex)
>>> _simplify_single_line(G(i0)*G(i1)*p(-i1)*G(-i0)) + 2*G(i0)*p(-i0)
0
"""
t1, t2 = extract_type_tens(expression, GammaMatrix)
if t1 != 1:
t1 = kahane_simplify(t1)
res = t1*t2
return res
def _trace_single_line(t):
"""
Evaluate the trace of a single gamma matrix line inside a ``TensExpr``.
Notes
=====
If there are ``DiracSpinorIndex.auto_left`` and ``DiracSpinorIndex.auto_right``
indices trace over them; otherwise traces are not implied (explain)
Examples
========
>>> from sympy.physics.hep.gamma_matrices import GammaMatrix as G, \
LorentzIndex, _trace_single_line
>>> from sympy.tensor.tensor import tensor_indices, TensorHead
>>> p = TensorHead('p', [LorentzIndex])
>>> i0,i1,i2,i3,i4,i5 = tensor_indices('i0:6', LorentzIndex)
>>> _trace_single_line(G(i0)*G(i1))
4*metric(i0, i1)
>>> _trace_single_line(G(i0)*p(-i0)*G(i1)*p(-i1)) - 4*p(i0)*p(-i0)
0
"""
def _trace_single_line1(t):
t = t.sorted_components()
components = t.components
ncomps = len(components)
g = LorentzIndex.metric
# gamma matirices are in a[i:j]
hit = 0
for i in range(ncomps):
if components[i] == GammaMatrix:
hit = 1
break
for j in range(i + hit, ncomps):
if components[j] != GammaMatrix:
break
else:
j = ncomps
numG = j - i
if numG == 0:
tcoeff = t.coeff
return t.nocoeff if tcoeff else t
if numG % 2 == 1:
return TensMul.from_data(S.Zero, [], [], [])
elif numG > 4:
# find the open matrix indices and connect them:
a = t.split()
ind1 = a[i].get_indices()[0]
ind2 = a[i + 1].get_indices()[0]
aa = a[:i] + a[i + 2:]
t1 = tensor_mul(*aa)*g(ind1, ind2)
t1 = t1.contract_metric(g)
args = [t1]
sign = 1
for k in range(i + 2, j):
sign = -sign
ind2 = a[k].get_indices()[0]
aa = a[:i] + a[i + 1:k] + a[k + 1:]
t2 = sign*tensor_mul(*aa)*g(ind1, ind2)
t2 = t2.contract_metric(g)
t2 = simplify_gpgp(t2, False)
args.append(t2)
t3 = TensAdd(*args)
t3 = _trace_single_line(t3)
return t3
else:
a = t.split()
t1 = _gamma_trace1(*a[i:j])
a2 = a[:i] + a[j:]
t2 = tensor_mul(*a2)
t3 = t1*t2
if not t3:
return t3
t3 = t3.contract_metric(g)
return t3
t = t.expand()
if isinstance(t, TensAdd):
a = [_trace_single_line1(x)*x.coeff for x in t.args]
return TensAdd(*a)
elif isinstance(t, (Tensor, TensMul)):
r = t.coeff*_trace_single_line1(t)
return r
else:
return trace(t)
def _gamma_trace1(*a):
gctr = 4 # FIXME specific for d=4
g = LorentzIndex.metric
if not a:
return gctr
n = len(a)
if n%2 == 1:
#return TensMul.from_data(S.Zero, [], [], [])
return S.Zero
if n == 2:
ind0 = a[0].get_indices()[0]
ind1 = a[1].get_indices()[0]
return gctr*g(ind0, ind1)
if n == 4:
ind0 = a[0].get_indices()[0]
ind1 = a[1].get_indices()[0]
ind2 = a[2].get_indices()[0]
ind3 = a[3].get_indices()[0]
return gctr*(g(ind0, ind1)*g(ind2, ind3) - \
g(ind0, ind2)*g(ind1, ind3) + g(ind0, ind3)*g(ind1, ind2))
def kahane_simplify(expression):
r"""
This function cancels contracted elements in a product of four
dimensional gamma matrices, resulting in an expression equal to the given
one, without the contracted gamma matrices.
Parameters
==========
`expression` the tensor expression containing the gamma matrices to simplify.
Notes
=====
If spinor indices are given, the matrices must be given in
the order given in the product.
Algorithm
=========
The idea behind the algorithm is to use some well-known identities,
i.e., for contractions enclosing an even number of `\gamma` matrices
`\gamma^\mu \gamma_{a_1} \cdots \gamma_{a_{2N}} \gamma_\mu = 2 (\gamma_{a_{2N}} \gamma_{a_1} \cdots \gamma_{a_{2N-1}} + \gamma_{a_{2N-1}} \cdots \gamma_{a_1} \gamma_{a_{2N}} )`
for an odd number of `\gamma` matrices
`\gamma^\mu \gamma_{a_1} \cdots \gamma_{a_{2N+1}} \gamma_\mu = -2 \gamma_{a_{2N+1}} \gamma_{a_{2N}} \cdots \gamma_{a_{1}}`
Instead of repeatedly applying these identities to cancel out all contracted indices,
it is possible to recognize the links that would result from such an operation,
the problem is thus reduced to a simple rearrangement of free gamma matrices.
Examples
========
When using, always remember that the original expression coefficient
has to be handled separately
>>> from sympy.physics.hep.gamma_matrices import GammaMatrix as G, LorentzIndex
>>> from sympy.physics.hep.gamma_matrices import kahane_simplify
>>> from sympy.tensor.tensor import tensor_indices
>>> i0, i1, i2 = tensor_indices('i0:3', LorentzIndex)
>>> ta = G(i0)*G(-i0)
>>> kahane_simplify(ta)
Matrix([
[4, 0, 0, 0],
[0, 4, 0, 0],
[0, 0, 4, 0],
[0, 0, 0, 4]])
>>> tb = G(i0)*G(i1)*G(-i0)
>>> kahane_simplify(tb)
-2*GammaMatrix(i1)
>>> t = G(i0)*G(-i0)
>>> kahane_simplify(t)
Matrix([
[4, 0, 0, 0],
[0, 4, 0, 0],
[0, 0, 4, 0],
[0, 0, 0, 4]])
>>> t = G(i0)*G(-i0)
>>> kahane_simplify(t)
Matrix([
[4, 0, 0, 0],
[0, 4, 0, 0],
[0, 0, 4, 0],
[0, 0, 0, 4]])
If there are no contractions, the same expression is returned
>>> tc = G(i0)*G(i1)
>>> kahane_simplify(tc)
GammaMatrix(i0)*GammaMatrix(i1)
References
==========
[1] Algorithm for Reducing Contracted Products of gamma Matrices,
Joseph Kahane, Journal of Mathematical Physics, Vol. 9, No. 10, October 1968.
"""
if isinstance(expression, Mul):
return expression
if isinstance(expression, TensAdd):
return TensAdd(*[kahane_simplify(arg) for arg in expression.args])
if isinstance(expression, Tensor):
return expression
assert isinstance(expression, TensMul)
gammas = expression.args
for gamma in gammas:
assert gamma.component == GammaMatrix
free = expression.free
# spinor_free = [_ for _ in expression.free_in_args if _[1] != 0]
# if len(spinor_free) == 2:
# spinor_free.sort(key=lambda x: x[2])
# assert spinor_free[0][1] == 1 and spinor_free[-1][1] == 2
# assert spinor_free[0][2] == 0
# elif spinor_free:
# raise ValueError('spinor indices do not match')
dum = []
for dum_pair in expression.dum:
if expression.index_types[dum_pair[0]] == LorentzIndex:
dum.append((dum_pair[0], dum_pair[1]))
dum = sorted(dum)
if len(dum) == 0: # or GammaMatrixHead:
# no contractions in `expression`, just return it.
return expression
# find the `first_dum_pos`, i.e. the position of the first contracted
# gamma matrix, Kahane's algorithm as described in his paper requires the
# gamma matrix expression to start with a contracted gamma matrix, this is
# a workaround which ignores possible initial free indices, and re-adds
# them later.
first_dum_pos = min(map(min, dum))
# for p1, p2, a1, a2 in expression.dum_in_args:
# if p1 != 0 or p2 != 0:
# # only Lorentz indices, skip Dirac indices:
# continue
# first_dum_pos = min(p1, p2)
# break
total_number = len(free) + len(dum)*2
number_of_contractions = len(dum)
free_pos = [None]*total_number
for i in free:
free_pos[i[1]] = i[0]
# `index_is_free` is a list of booleans, to identify index position
# and whether that index is free or dummy.
index_is_free = [False]*total_number
for i, indx in enumerate(free):
index_is_free[indx[1]] = True
# `links` is a dictionary containing the graph described in Kahane's paper,
# to every key correspond one or two values, representing the linked indices.
# All values in `links` are integers, negative numbers are used in the case
# where it is necessary to insert gamma matrices between free indices, in
# order to make Kahane's algorithm work (see paper).
links = {i: [] for i in range(first_dum_pos, total_number)}
# `cum_sign` is a step variable to mark the sign of every index, see paper.
cum_sign = -1
# `cum_sign_list` keeps storage for all `cum_sign` (every index).
cum_sign_list = [None]*total_number
block_free_count = 0
# multiply `resulting_coeff` by the coefficient parameter, the rest
# of the algorithm ignores a scalar coefficient.
resulting_coeff = S.One
# initialize a list of lists of indices. The outer list will contain all
# additive tensor expressions, while the inner list will contain the
# free indices (rearranged according to the algorithm).
resulting_indices = [[]]
# start to count the `connected_components`, which together with the number
# of contractions, determines a -1 or +1 factor to be multiplied.
connected_components = 1
# First loop: here we fill `cum_sign_list`, and draw the links
# among consecutive indices (they are stored in `links`). Links among
# non-consecutive indices will be drawn later.
for i, is_free in enumerate(index_is_free):
# if `expression` starts with free indices, they are ignored here;
# they are later added as they are to the beginning of all
# `resulting_indices` list of lists of indices.
if i < first_dum_pos:
continue
if is_free:
block_free_count += 1
# if previous index was free as well, draw an arch in `links`.
if block_free_count > 1:
links[i - 1].append(i)
links[i].append(i - 1)
else:
# Change the sign of the index (`cum_sign`) if the number of free
# indices preceding it is even.
cum_sign *= 1 if (block_free_count % 2) else -1
if block_free_count == 0 and i != first_dum_pos:
# check if there are two consecutive dummy indices:
# in this case create virtual indices with negative position,
# these "virtual" indices represent the insertion of two
# gamma^0 matrices to separate consecutive dummy indices, as
# Kahane's algorithm requires dummy indices to be separated by
# free indices. The product of two gamma^0 matrices is unity,
# so the new expression being examined is the same as the
# original one.
if cum_sign == -1:
links[-1-i] = [-1-i+1]
links[-1-i+1] = [-1-i]
if (i - cum_sign) in links:
if i != first_dum_pos:
links[i].append(i - cum_sign)
if block_free_count != 0:
if i - cum_sign < len(index_is_free):
if index_is_free[i - cum_sign]:
links[i - cum_sign].append(i)
block_free_count = 0
cum_sign_list[i] = cum_sign
# The previous loop has only created links between consecutive free indices,
# it is necessary to properly create links among dummy (contracted) indices,
# according to the rules described in Kahane's paper. There is only one exception
# to Kahane's rules: the negative indices, which handle the case of some
# consecutive free indices (Kahane's paper just describes dummy indices
# separated by free indices, hinting that free indices can be added without
# altering the expression result).
for i in dum:
# get the positions of the two contracted indices:
pos1 = i[0]
pos2 = i[1]
# create Kahane's upper links, i.e. the upper arcs between dummy
# (i.e. contracted) indices:
links[pos1].append(pos2)
links[pos2].append(pos1)
# create Kahane's lower links, this corresponds to the arcs below
# the line described in the paper:
# first we move `pos1` and `pos2` according to the sign of the indices:
linkpos1 = pos1 + cum_sign_list[pos1]
linkpos2 = pos2 + cum_sign_list[pos2]
# otherwise, perform some checks before creating the lower arcs:
# make sure we are not exceeding the total number of indices:
if linkpos1 >= total_number:
continue
if linkpos2 >= total_number:
continue
# make sure we are not below the first dummy index in `expression`:
if linkpos1 < first_dum_pos:
continue
if linkpos2 < first_dum_pos:
continue
# check if the previous loop created "virtual" indices between dummy
# indices, in such a case relink `linkpos1` and `linkpos2`:
if (-1-linkpos1) in links:
linkpos1 = -1-linkpos1
if (-1-linkpos2) in links:
linkpos2 = -1-linkpos2
# move only if not next to free index:
if linkpos1 >= 0 and not index_is_free[linkpos1]:
linkpos1 = pos1
if linkpos2 >=0 and not index_is_free[linkpos2]:
linkpos2 = pos2
# create the lower arcs:
if linkpos2 not in links[linkpos1]:
links[linkpos1].append(linkpos2)
if linkpos1 not in links[linkpos2]:
links[linkpos2].append(linkpos1)
# This loop starts from the `first_dum_pos` index (first dummy index)
# walks through the graph deleting the visited indices from `links`,
# it adds a gamma matrix for every free index in encounters, while it
# completely ignores dummy indices and virtual indices.
pointer = first_dum_pos
previous_pointer = 0
while True:
if pointer in links:
next_ones = links.pop(pointer)
else:
break
if previous_pointer in next_ones:
next_ones.remove(previous_pointer)
previous_pointer = pointer
if next_ones:
pointer = next_ones[0]
else:
break
if pointer == previous_pointer:
break
if pointer >=0 and free_pos[pointer] is not None:
for ri in resulting_indices:
ri.append(free_pos[pointer])
# The following loop removes the remaining connected components in `links`.
# If there are free indices inside a connected component, it gives a
# contribution to the resulting expression given by the factor
# `gamma_a gamma_b ... gamma_z + gamma_z ... gamma_b gamma_a`, in Kahanes's
# paper represented as {gamma_a, gamma_b, ... , gamma_z},
# virtual indices are ignored. The variable `connected_components` is
# increased by one for every connected component this loop encounters.
# If the connected component has virtual and dummy indices only
# (no free indices), it contributes to `resulting_indices` by a factor of two.
# The multiplication by two is a result of the
# factor {gamma^0, gamma^0} = 2 I, as it appears in Kahane's paper.
# Note: curly brackets are meant as in the paper, as a generalized
# multi-element anticommutator!
while links:
connected_components += 1
pointer = min(links.keys())
previous_pointer = pointer
# the inner loop erases the visited indices from `links`, and it adds
# all free indices to `prepend_indices` list, virtual indices are
# ignored.
prepend_indices = []
while True:
if pointer in links:
next_ones = links.pop(pointer)
else:
break
if previous_pointer in next_ones:
if len(next_ones) > 1:
next_ones.remove(previous_pointer)
previous_pointer = pointer
if next_ones:
pointer = next_ones[0]
if pointer >= first_dum_pos and free_pos[pointer] is not None:
prepend_indices.insert(0, free_pos[pointer])
# if `prepend_indices` is void, it means there are no free indices
# in the loop (and it can be shown that there must be a virtual index),
# loops of virtual indices only contribute by a factor of two:
if len(prepend_indices) == 0:
resulting_coeff *= 2
# otherwise, add the free indices in `prepend_indices` to
# the `resulting_indices`:
else:
expr1 = prepend_indices
expr2 = list(reversed(prepend_indices))
resulting_indices = [expri + ri for ri in resulting_indices for expri in (expr1, expr2)]
# sign correction, as described in Kahane's paper:
resulting_coeff *= -1 if (number_of_contractions - connected_components + 1) % 2 else 1
# power of two factor, as described in Kahane's paper:
resulting_coeff *= 2**(number_of_contractions)
# If `first_dum_pos` is not zero, it means that there are trailing free gamma
# matrices in front of `expression`, so multiply by them:
resulting_indices = [ free_pos[0:first_dum_pos] + ri for ri in resulting_indices ]
resulting_expr = S.Zero
for i in resulting_indices:
temp_expr = S.One
for j in i:
temp_expr *= GammaMatrix(j)
resulting_expr += temp_expr
t = resulting_coeff * resulting_expr
t1 = None
if isinstance(t, TensAdd):
t1 = t.args[0]
elif isinstance(t, TensMul):
t1 = t
if t1:
pass
else:
t = eye(4)*t
return t
PK ]ZZZ~�"� # sympy/physics/mechanics/__init__.py__all__ = [
'vector',
'CoordinateSym', 'ReferenceFrame', 'Dyadic', 'Vector', 'Point', 'cross',
'dot', 'express', 'time_derivative', 'outer', 'kinematic_equations',
'get_motion_params', 'partial_velocity', 'dynamicsymbols', 'vprint',
'vsstrrepr', 'vsprint', 'vpprint', 'vlatex', 'init_vprinting', 'curl',
'divergence', 'gradient', 'is_conservative', 'is_solenoidal',
'scalar_potential', 'scalar_potential_difference',
'KanesMethod',
'RigidBody',
'linear_momentum', 'angular_momentum', 'kinetic_energy', 'potential_energy',
'Lagrangian', 'mechanics_printing', 'mprint', 'msprint', 'mpprint',
'mlatex', 'msubs', 'find_dynamicsymbols',
'inertia', 'inertia_of_point_mass', 'Inertia',
'Force', 'Torque',
'Particle',
'LagrangesMethod',
'Linearizer',
'Body',
'SymbolicSystem', 'System',
'PinJoint', 'PrismaticJoint', 'CylindricalJoint', 'PlanarJoint',
'SphericalJoint', 'WeldJoint',
'JointsMethod',
'WrappingCylinder', 'WrappingGeometryBase', 'WrappingSphere',
'PathwayBase', 'LinearPathway', 'ObstacleSetPathway', 'WrappingPathway',
'ActuatorBase', 'ForceActuator', 'LinearDamper', 'LinearSpring',
'TorqueActuator', 'DuffingSpring'
]
from sympy.physics import vector
from sympy.physics.vector import (CoordinateSym, ReferenceFrame, Dyadic, Vector, Point,
cross, dot, express, time_derivative, outer, kinematic_equations,
get_motion_params, partial_velocity, dynamicsymbols, vprint,
vsstrrepr, vsprint, vpprint, vlatex, init_vprinting, curl, divergence,
gradient, is_conservative, is_solenoidal, scalar_potential,
scalar_potential_difference)
from .kane import KanesMethod
from .rigidbody import RigidBody
from .functions import (linear_momentum, angular_momentum, kinetic_energy,
potential_energy, Lagrangian, mechanics_printing,
mprint, msprint, mpprint, mlatex, msubs,
find_dynamicsymbols)
from .inertia import inertia, inertia_of_point_mass, Inertia
from .loads import Force, Torque
from .particle import Particle
from .lagrange import LagrangesMethod
from .linearize import Linearizer
from .body import Body
from .system import SymbolicSystem, System
from .jointsmethod import JointsMethod
from .joint import (PinJoint, PrismaticJoint, CylindricalJoint, PlanarJoint,
SphericalJoint, WeldJoint)
from .wrapping_geometry import (WrappingCylinder, WrappingGeometryBase,
WrappingSphere)
from .pathway import (PathwayBase, LinearPathway, ObstacleSetPathway,
WrappingPathway)
from .actuator import (ActuatorBase, ForceActuator, LinearDamper, LinearSpring,
TorqueActuator, DuffingSpring)
PK ]ZZZR �� � # sympy/physics/mechanics/actuator.py"""Implementations of actuators for linked force and torque application."""
from abc import ABC, abstractmethod
from sympy import S, sympify
from sympy.physics.mechanics.joint import PinJoint
from sympy.physics.mechanics.loads import Torque
from sympy.physics.mechanics.pathway import PathwayBase
from sympy.physics.mechanics.rigidbody import RigidBody
from sympy.physics.vector import ReferenceFrame, Vector
__all__ = [
'ActuatorBase',
'ForceActuator',
'LinearDamper',
'LinearSpring',
'TorqueActuator',
'DuffingSpring'
]
class ActuatorBase(ABC):
"""Abstract base class for all actuator classes to inherit from.
Notes
=====
Instances of this class cannot be directly instantiated by users. However,
it can be used to created custom actuator types through subclassing.
"""
def __init__(self):
"""Initializer for ``ActuatorBase``."""
pass
@abstractmethod
def to_loads(self):
"""Loads required by the equations of motion method classes.
Explanation
===========
``KanesMethod`` requires a list of ``Point``-``Vector`` tuples to be
passed to the ``loads`` parameters of its ``kanes_equations`` method
when constructing the equations of motion. This method acts as a
utility to produce the correctly-structred pairs of points and vectors
required so that these can be easily concatenated with other items in
the list of loads and passed to ``KanesMethod.kanes_equations``. These
loads are also in the correct form to also be passed to the other
equations of motion method classes, e.g. ``LagrangesMethod``.
"""
pass
def __repr__(self):
"""Default representation of an actuator."""
return f'{self.__class__.__name__}()'
class ForceActuator(ActuatorBase):
"""Force-producing actuator.
Explanation
===========
A ``ForceActuator`` is an actuator that produces a (expansile) force along
its length.
A force actuator uses a pathway instance to determine the direction and
number of forces that it applies to a system. Consider the simplest case
where a ``LinearPathway`` instance is used. This pathway is made up of two
points that can move relative to each other, and results in a pair of equal
and opposite forces acting on the endpoints. If the positive time-varying
Euclidean distance between the two points is defined, then the "extension
velocity" is the time derivative of this distance. The extension velocity
is positive when the two points are moving away from each other and
negative when moving closer to each other. The direction for the force
acting on either point is determined by constructing a unit vector directed
from the other point to this point. This establishes a sign convention such
that a positive force magnitude tends to push the points apart, this is the
meaning of "expansile" in this context. The following diagram shows the
positive force sense and the distance between the points::
P Q
o<--- F --->o
| |
|<--l(t)--->|
Examples
========
To construct an actuator, an expression (or symbol) must be supplied to
represent the force it can produce, alongside a pathway specifying its line
of action. Let's also create a global reference frame and spatially fix one
of the points in it while setting the other to be positioned such that it
can freely move in the frame's x direction specified by the coordinate
``q``.
>>> from sympy import symbols
>>> from sympy.physics.mechanics import (ForceActuator, LinearPathway,
... Point, ReferenceFrame)
>>> from sympy.physics.vector import dynamicsymbols
>>> N = ReferenceFrame('N')
>>> q = dynamicsymbols('q')
>>> force = symbols('F')
>>> pA, pB = Point('pA'), Point('pB')
>>> pA.set_vel(N, 0)
>>> pB.set_pos(pA, q*N.x)
>>> pB.pos_from(pA)
q(t)*N.x
>>> linear_pathway = LinearPathway(pA, pB)
>>> actuator = ForceActuator(force, linear_pathway)
>>> actuator
ForceActuator(F, LinearPathway(pA, pB))
Parameters
==========
force : Expr
The scalar expression defining the (expansile) force that the actuator
produces.
pathway : PathwayBase
The pathway that the actuator follows. This must be an instance of a
concrete subclass of ``PathwayBase``, e.g. ``LinearPathway``.
"""
def __init__(self, force, pathway):
"""Initializer for ``ForceActuator``.
Parameters
==========
force : Expr
The scalar expression defining the (expansile) force that the
actuator produces.
pathway : PathwayBase
The pathway that the actuator follows. This must be an instance of
a concrete subclass of ``PathwayBase``, e.g. ``LinearPathway``.
"""
self.force = force
self.pathway = pathway
@property
def force(self):
"""The magnitude of the force produced by the actuator."""
return self._force
@force.setter
def force(self, force):
if hasattr(self, '_force'):
msg = (
f'Can\'t set attribute `force` to {repr(force)} as it is '
f'immutable.'
)
raise AttributeError(msg)
self._force = sympify(force, strict=True)
@property
def pathway(self):
"""The ``Pathway`` defining the actuator's line of action."""
return self._pathway
@pathway.setter
def pathway(self, pathway):
if hasattr(self, '_pathway'):
msg = (
f'Can\'t set attribute `pathway` to {repr(pathway)} as it is '
f'immutable.'
)
raise AttributeError(msg)
if not isinstance(pathway, PathwayBase):
msg = (
f'Value {repr(pathway)} passed to `pathway` was of type '
f'{type(pathway)}, must be {PathwayBase}.'
)
raise TypeError(msg)
self._pathway = pathway
def to_loads(self):
"""Loads required by the equations of motion method classes.
Explanation
===========
``KanesMethod`` requires a list of ``Point``-``Vector`` tuples to be
passed to the ``loads`` parameters of its ``kanes_equations`` method
when constructing the equations of motion. This method acts as a
utility to produce the correctly-structred pairs of points and vectors
required so that these can be easily concatenated with other items in
the list of loads and passed to ``KanesMethod.kanes_equations``. These
loads are also in the correct form to also be passed to the other
equations of motion method classes, e.g. ``LagrangesMethod``.
Examples
========
The below example shows how to generate the loads produced by a force
actuator that follows a linear pathway. In this example we'll assume
that the force actuator is being used to model a simple linear spring.
First, create a linear pathway between two points separated by the
coordinate ``q`` in the ``x`` direction of the global frame ``N``.
>>> from sympy.physics.mechanics import (LinearPathway, Point,
... ReferenceFrame)
>>> from sympy.physics.vector import dynamicsymbols
>>> q = dynamicsymbols('q')
>>> N = ReferenceFrame('N')
>>> pA, pB = Point('pA'), Point('pB')
>>> pB.set_pos(pA, q*N.x)
>>> pathway = LinearPathway(pA, pB)
Now create a symbol ``k`` to describe the spring's stiffness and
instantiate a force actuator that produces a (contractile) force
proportional to both the spring's stiffness and the pathway's length.
Note that actuator classes use the sign convention that expansile
forces are positive, so for a spring to produce a contractile force the
spring force needs to be calculated as the negative for the stiffness
multiplied by the length.
>>> from sympy import symbols
>>> from sympy.physics.mechanics import ForceActuator
>>> stiffness = symbols('k')
>>> spring_force = -stiffness*pathway.length
>>> spring = ForceActuator(spring_force, pathway)
The forces produced by the spring can be generated in the list of loads
form that ``KanesMethod`` (and other equations of motion methods)
requires by calling the ``to_loads`` method.
>>> spring.to_loads()
[(pA, k*q(t)*N.x), (pB, - k*q(t)*N.x)]
A simple linear damper can be modeled in a similar way. Create another
symbol ``c`` to describe the dampers damping coefficient. This time
instantiate a force actuator that produces a force proportional to both
the damper's damping coefficient and the pathway's extension velocity.
Note that the damping force is negative as it acts in the opposite
direction to which the damper is changing in length.
>>> damping_coefficient = symbols('c')
>>> damping_force = -damping_coefficient*pathway.extension_velocity
>>> damper = ForceActuator(damping_force, pathway)
Again, the forces produces by the damper can be generated by calling
the ``to_loads`` method.
>>> damper.to_loads()
[(pA, c*Derivative(q(t), t)*N.x), (pB, - c*Derivative(q(t), t)*N.x)]
"""
return self.pathway.to_loads(self.force)
def __repr__(self):
"""Representation of a ``ForceActuator``."""
return f'{self.__class__.__name__}({self.force}, {self.pathway})'
class LinearSpring(ForceActuator):
"""A spring with its spring force as a linear function of its length.
Explanation
===========
Note that the "linear" in the name ``LinearSpring`` refers to the fact that
the spring force is a linear function of the springs length. I.e. for a
linear spring with stiffness ``k``, distance between its ends of ``x``, and
an equilibrium length of ``0``, the spring force will be ``-k*x``, which is
a linear function in ``x``. To create a spring that follows a linear, or
straight, pathway between its two ends, a ``LinearPathway`` instance needs
to be passed to the ``pathway`` parameter.
A ``LinearSpring`` is a subclass of ``ForceActuator`` and so follows the
same sign conventions for length, extension velocity, and the direction of
the forces it applies to its points of attachment on bodies. The sign
convention for the direction of forces is such that, for the case where a
linear spring is instantiated with a ``LinearPathway`` instance as its
pathway, they act to push the two ends of the spring away from one another.
Because springs produces a contractile force and acts to pull the two ends
together towards the equilibrium length when stretched, the scalar portion
of the forces on the endpoint are negative in order to flip the sign of the
forces on the endpoints when converted into vector quantities. The
following diagram shows the positive force sense and the distance between
the points::
P Q
o<--- F --->o
| |
|<--l(t)--->|
Examples
========
To construct a linear spring, an expression (or symbol) must be supplied to
represent the stiffness (spring constant) of the spring, alongside a
pathway specifying its line of action. Let's also create a global reference
frame and spatially fix one of the points in it while setting the other to
be positioned such that it can freely move in the frame's x direction
specified by the coordinate ``q``.
>>> from sympy import symbols
>>> from sympy.physics.mechanics import (LinearPathway, LinearSpring,
... Point, ReferenceFrame)
>>> from sympy.physics.vector import dynamicsymbols
>>> N = ReferenceFrame('N')
>>> q = dynamicsymbols('q')
>>> stiffness = symbols('k')
>>> pA, pB = Point('pA'), Point('pB')
>>> pA.set_vel(N, 0)
>>> pB.set_pos(pA, q*N.x)
>>> pB.pos_from(pA)
q(t)*N.x
>>> linear_pathway = LinearPathway(pA, pB)
>>> spring = LinearSpring(stiffness, linear_pathway)
>>> spring
LinearSpring(k, LinearPathway(pA, pB))
This spring will produce a force that is proportional to both its stiffness
and the pathway's length. Note that this force is negative as SymPy's sign
convention for actuators is that negative forces are contractile.
>>> spring.force
-k*sqrt(q(t)**2)
To create a linear spring with a non-zero equilibrium length, an expression
(or symbol) can be passed to the ``equilibrium_length`` parameter on
construction on a ``LinearSpring`` instance. Let's create a symbol ``l``
to denote a non-zero equilibrium length and create another linear spring.
>>> l = symbols('l')
>>> spring = LinearSpring(stiffness, linear_pathway, equilibrium_length=l)
>>> spring
LinearSpring(k, LinearPathway(pA, pB), equilibrium_length=l)
The spring force of this new spring is again proportional to both its
stiffness and the pathway's length. However, the spring will not produce
any force when ``q(t)`` equals ``l``. Note that the force will become
expansile when ``q(t)`` is less than ``l``, as expected.
>>> spring.force
-k*(-l + sqrt(q(t)**2))
Parameters
==========
stiffness : Expr
The spring constant.
pathway : PathwayBase
The pathway that the actuator follows. This must be an instance of a
concrete subclass of ``PathwayBase``, e.g. ``LinearPathway``.
equilibrium_length : Expr, optional
The length at which the spring is in equilibrium, i.e. it produces no
force. The default value is 0, i.e. the spring force is a linear
function of the pathway's length with no constant offset.
See Also
========
ForceActuator: force-producing actuator (superclass of ``LinearSpring``).
LinearPathway: straight-line pathway between a pair of points.
"""
def __init__(self, stiffness, pathway, equilibrium_length=S.Zero):
"""Initializer for ``LinearSpring``.
Parameters
==========
stiffness : Expr
The spring constant.
pathway : PathwayBase
The pathway that the actuator follows. This must be an instance of
a concrete subclass of ``PathwayBase``, e.g. ``LinearPathway``.
equilibrium_length : Expr, optional
The length at which the spring is in equilibrium, i.e. it produces
no force. The default value is 0, i.e. the spring force is a linear
function of the pathway's length with no constant offset.
"""
self.stiffness = stiffness
self.pathway = pathway
self.equilibrium_length = equilibrium_length
@property
def force(self):
"""The spring force produced by the linear spring."""
return -self.stiffness*(self.pathway.length - self.equilibrium_length)
@force.setter
def force(self, force):
raise AttributeError('Can\'t set computed attribute `force`.')
@property
def stiffness(self):
"""The spring constant for the linear spring."""
return self._stiffness
@stiffness.setter
def stiffness(self, stiffness):
if hasattr(self, '_stiffness'):
msg = (
f'Can\'t set attribute `stiffness` to {repr(stiffness)} as it '
f'is immutable.'
)
raise AttributeError(msg)
self._stiffness = sympify(stiffness, strict=True)
@property
def equilibrium_length(self):
"""The length of the spring at which it produces no force."""
return self._equilibrium_length
@equilibrium_length.setter
def equilibrium_length(self, equilibrium_length):
if hasattr(self, '_equilibrium_length'):
msg = (
f'Can\'t set attribute `equilibrium_length` to '
f'{repr(equilibrium_length)} as it is immutable.'
)
raise AttributeError(msg)
self._equilibrium_length = sympify(equilibrium_length, strict=True)
def __repr__(self):
"""Representation of a ``LinearSpring``."""
string = f'{self.__class__.__name__}({self.stiffness}, {self.pathway}'
if self.equilibrium_length == S.Zero:
string += ')'
else:
string += f', equilibrium_length={self.equilibrium_length})'
return string
class LinearDamper(ForceActuator):
"""A damper whose force is a linear function of its extension velocity.
Explanation
===========
Note that the "linear" in the name ``LinearDamper`` refers to the fact that
the damping force is a linear function of the damper's rate of change in
its length. I.e. for a linear damper with damping ``c`` and extension
velocity ``v``, the damping force will be ``-c*v``, which is a linear
function in ``v``. To create a damper that follows a linear, or straight,
pathway between its two ends, a ``LinearPathway`` instance needs to be
passed to the ``pathway`` parameter.
A ``LinearDamper`` is a subclass of ``ForceActuator`` and so follows the
same sign conventions for length, extension velocity, and the direction of
the forces it applies to its points of attachment on bodies. The sign
convention for the direction of forces is such that, for the case where a
linear damper is instantiated with a ``LinearPathway`` instance as its
pathway, they act to push the two ends of the damper away from one another.
Because dampers produce a force that opposes the direction of change in
length, when extension velocity is positive the scalar portions of the
forces applied at the two endpoints are negative in order to flip the sign
of the forces on the endpoints wen converted into vector quantities. When
extension velocity is negative (i.e. when the damper is shortening), the
scalar portions of the fofces applied are also negative so that the signs
cancel producing forces on the endpoints that are in the same direction as
the positive sign convention for the forces at the endpoints of the pathway
(i.e. they act to push the endpoints away from one another). The following
diagram shows the positive force sense and the distance between the
points::
P Q
o<--- F --->o
| |
|<--l(t)--->|
Examples
========
To construct a linear damper, an expression (or symbol) must be supplied to
represent the damping coefficient of the damper (we'll use the symbol
``c``), alongside a pathway specifying its line of action. Let's also
create a global reference frame and spatially fix one of the points in it
while setting the other to be positioned such that it can freely move in
the frame's x direction specified by the coordinate ``q``. The velocity
that the two points move away from one another can be specified by the
coordinate ``u`` where ``u`` is the first time derivative of ``q``
(i.e., ``u = Derivative(q(t), t)``).
>>> from sympy import symbols
>>> from sympy.physics.mechanics import (LinearDamper, LinearPathway,
... Point, ReferenceFrame)
>>> from sympy.physics.vector import dynamicsymbols
>>> N = ReferenceFrame('N')
>>> q = dynamicsymbols('q')
>>> damping = symbols('c')
>>> pA, pB = Point('pA'), Point('pB')
>>> pA.set_vel(N, 0)
>>> pB.set_pos(pA, q*N.x)
>>> pB.pos_from(pA)
q(t)*N.x
>>> pB.vel(N)
Derivative(q(t), t)*N.x
>>> linear_pathway = LinearPathway(pA, pB)
>>> damper = LinearDamper(damping, linear_pathway)
>>> damper
LinearDamper(c, LinearPathway(pA, pB))
This damper will produce a force that is proportional to both its damping
coefficient and the pathway's extension length. Note that this force is
negative as SymPy's sign convention for actuators is that negative forces
are contractile and the damping force of the damper will oppose the
direction of length change.
>>> damper.force
-c*sqrt(q(t)**2)*Derivative(q(t), t)/q(t)
Parameters
==========
damping : Expr
The damping constant.
pathway : PathwayBase
The pathway that the actuator follows. This must be an instance of a
concrete subclass of ``PathwayBase``, e.g. ``LinearPathway``.
See Also
========
ForceActuator: force-producing actuator (superclass of ``LinearDamper``).
LinearPathway: straight-line pathway between a pair of points.
"""
def __init__(self, damping, pathway):
"""Initializer for ``LinearDamper``.
Parameters
==========
damping : Expr
The damping constant.
pathway : PathwayBase
The pathway that the actuator follows. This must be an instance of
a concrete subclass of ``PathwayBase``, e.g. ``LinearPathway``.
"""
self.damping = damping
self.pathway = pathway
@property
def force(self):
"""The damping force produced by the linear damper."""
return -self.damping*self.pathway.extension_velocity
@force.setter
def force(self, force):
raise AttributeError('Can\'t set computed attribute `force`.')
@property
def damping(self):
"""The damping constant for the linear damper."""
return self._damping
@damping.setter
def damping(self, damping):
if hasattr(self, '_damping'):
msg = (
f'Can\'t set attribute `damping` to {repr(damping)} as it is '
f'immutable.'
)
raise AttributeError(msg)
self._damping = sympify(damping, strict=True)
def __repr__(self):
"""Representation of a ``LinearDamper``."""
return f'{self.__class__.__name__}({self.damping}, {self.pathway})'
class TorqueActuator(ActuatorBase):
"""Torque-producing actuator.
Explanation
===========
A ``TorqueActuator`` is an actuator that produces a pair of equal and
opposite torques on a pair of bodies.
Examples
========
To construct a torque actuator, an expression (or symbol) must be supplied
to represent the torque it can produce, alongside a vector specifying the
axis about which the torque will act, and a pair of frames on which the
torque will act.
>>> from sympy import symbols
>>> from sympy.physics.mechanics import (ReferenceFrame, RigidBody,
... TorqueActuator)
>>> N = ReferenceFrame('N')
>>> A = ReferenceFrame('A')
>>> torque = symbols('T')
>>> axis = N.z
>>> parent = RigidBody('parent', frame=N)
>>> child = RigidBody('child', frame=A)
>>> bodies = (child, parent)
>>> actuator = TorqueActuator(torque, axis, *bodies)
>>> actuator
TorqueActuator(T, axis=N.z, target_frame=A, reaction_frame=N)
Note that because torques actually act on frames, not bodies,
``TorqueActuator`` will extract the frame associated with a ``RigidBody``
when one is passed instead of a ``ReferenceFrame``.
Parameters
==========
torque : Expr
The scalar expression defining the torque that the actuator produces.
axis : Vector
The axis about which the actuator applies torques.
target_frame : ReferenceFrame | RigidBody
The primary frame on which the actuator will apply the torque.
reaction_frame : ReferenceFrame | RigidBody | None
The secondary frame on which the actuator will apply the torque. Note
that the (equal and opposite) reaction torque is applied to this frame.
"""
def __init__(self, torque, axis, target_frame, reaction_frame=None):
"""Initializer for ``TorqueActuator``.
Parameters
==========
torque : Expr
The scalar expression defining the torque that the actuator
produces.
axis : Vector
The axis about which the actuator applies torques.
target_frame : ReferenceFrame | RigidBody
The primary frame on which the actuator will apply the torque.
reaction_frame : ReferenceFrame | RigidBody | None
The secondary frame on which the actuator will apply the torque.
Note that the (equal and opposite) reaction torque is applied to
this frame.
"""
self.torque = torque
self.axis = axis
self.target_frame = target_frame
self.reaction_frame = reaction_frame
@classmethod
def at_pin_joint(cls, torque, pin_joint):
"""Alternate construtor to instantiate from a ``PinJoint`` instance.
Examples
========
To create a pin joint the ``PinJoint`` class requires a name, parent
body, and child body to be passed to its constructor. It is also
possible to control the joint axis using the ``joint_axis`` keyword
argument. In this example let's use the parent body's reference frame's
z-axis as the joint axis.
>>> from sympy.physics.mechanics import (PinJoint, ReferenceFrame,
... RigidBody, TorqueActuator)
>>> N = ReferenceFrame('N')
>>> A = ReferenceFrame('A')
>>> parent = RigidBody('parent', frame=N)
>>> child = RigidBody('child', frame=A)
>>> pin_joint = PinJoint(
... 'pin',
... parent,
... child,
... joint_axis=N.z,
... )
Let's also create a symbol ``T`` that will represent the torque applied
by the torque actuator.
>>> from sympy import symbols
>>> torque = symbols('T')
To create the torque actuator from the ``torque`` and ``pin_joint``
variables previously instantiated, these can be passed to the alternate
constructor class method ``at_pin_joint`` of the ``TorqueActuator``
class. It should be noted that a positive torque will cause a positive
displacement of the joint coordinate or that the torque is applied on
the child body with a reaction torque on the parent.
>>> actuator = TorqueActuator.at_pin_joint(torque, pin_joint)
>>> actuator
TorqueActuator(T, axis=N.z, target_frame=A, reaction_frame=N)
Parameters
==========
torque : Expr
The scalar expression defining the torque that the actuator
produces.
pin_joint : PinJoint
The pin joint, and by association the parent and child bodies, on
which the torque actuator will act. The pair of bodies acted upon
by the torque actuator are the parent and child bodies of the pin
joint, with the child acting as the reaction body. The pin joint's
axis is used as the axis about which the torque actuator will apply
its torque.
"""
if not isinstance(pin_joint, PinJoint):
msg = (
f'Value {repr(pin_joint)} passed to `pin_joint` was of type '
f'{type(pin_joint)}, must be {PinJoint}.'
)
raise TypeError(msg)
return cls(
torque,
pin_joint.joint_axis,
pin_joint.child_interframe,
pin_joint.parent_interframe,
)
@property
def torque(self):
"""The magnitude of the torque produced by the actuator."""
return self._torque
@torque.setter
def torque(self, torque):
if hasattr(self, '_torque'):
msg = (
f'Can\'t set attribute `torque` to {repr(torque)} as it is '
f'immutable.'
)
raise AttributeError(msg)
self._torque = sympify(torque, strict=True)
@property
def axis(self):
"""The axis about which the torque acts."""
return self._axis
@axis.setter
def axis(self, axis):
if hasattr(self, '_axis'):
msg = (
f'Can\'t set attribute `axis` to {repr(axis)} as it is '
f'immutable.'
)
raise AttributeError(msg)
if not isinstance(axis, Vector):
msg = (
f'Value {repr(axis)} passed to `axis` was of type '
f'{type(axis)}, must be {Vector}.'
)
raise TypeError(msg)
self._axis = axis
@property
def target_frame(self):
"""The primary reference frames on which the torque will act."""
return self._target_frame
@target_frame.setter
def target_frame(self, target_frame):
if hasattr(self, '_target_frame'):
msg = (
f'Can\'t set attribute `target_frame` to {repr(target_frame)} '
f'as it is immutable.'
)
raise AttributeError(msg)
if isinstance(target_frame, RigidBody):
target_frame = target_frame.frame
elif not isinstance(target_frame, ReferenceFrame):
msg = (
f'Value {repr(target_frame)} passed to `target_frame` was of '
f'type {type(target_frame)}, must be {ReferenceFrame}.'
)
raise TypeError(msg)
self._target_frame = target_frame
@property
def reaction_frame(self):
"""The primary reference frames on which the torque will act."""
return self._reaction_frame
@reaction_frame.setter
def reaction_frame(self, reaction_frame):
if hasattr(self, '_reaction_frame'):
msg = (
f'Can\'t set attribute `reaction_frame` to '
f'{repr(reaction_frame)} as it is immutable.'
)
raise AttributeError(msg)
if isinstance(reaction_frame, RigidBody):
reaction_frame = reaction_frame.frame
elif (
not isinstance(reaction_frame, ReferenceFrame)
and reaction_frame is not None
):
msg = (
f'Value {repr(reaction_frame)} passed to `reaction_frame` was '
f'of type {type(reaction_frame)}, must be {ReferenceFrame}.'
)
raise TypeError(msg)
self._reaction_frame = reaction_frame
def to_loads(self):
"""Loads required by the equations of motion method classes.
Explanation
===========
``KanesMethod`` requires a list of ``Point``-``Vector`` tuples to be
passed to the ``loads`` parameters of its ``kanes_equations`` method
when constructing the equations of motion. This method acts as a
utility to produce the correctly-structred pairs of points and vectors
required so that these can be easily concatenated with other items in
the list of loads and passed to ``KanesMethod.kanes_equations``. These
loads are also in the correct form to also be passed to the other
equations of motion method classes, e.g. ``LagrangesMethod``.
Examples
========
The below example shows how to generate the loads produced by a torque
actuator that acts on a pair of bodies attached by a pin joint.
>>> from sympy import symbols
>>> from sympy.physics.mechanics import (PinJoint, ReferenceFrame,
... RigidBody, TorqueActuator)
>>> torque = symbols('T')
>>> N = ReferenceFrame('N')
>>> A = ReferenceFrame('A')
>>> parent = RigidBody('parent', frame=N)
>>> child = RigidBody('child', frame=A)
>>> pin_joint = PinJoint(
... 'pin',
... parent,
... child,
... joint_axis=N.z,
... )
>>> actuator = TorqueActuator.at_pin_joint(torque, pin_joint)
The forces produces by the damper can be generated by calling the
``to_loads`` method.
>>> actuator.to_loads()
[(A, T*N.z), (N, - T*N.z)]
Alternatively, if a torque actuator is created without a reaction frame
then the loads returned by the ``to_loads`` method will contain just
the single load acting on the target frame.
>>> actuator = TorqueActuator(torque, N.z, N)
>>> actuator.to_loads()
[(N, T*N.z)]
"""
loads = [
Torque(self.target_frame, self.torque*self.axis),
]
if self.reaction_frame is not None:
loads.append(Torque(self.reaction_frame, -self.torque*self.axis))
return loads
def __repr__(self):
"""Representation of a ``TorqueActuator``."""
string = (
f'{self.__class__.__name__}({self.torque}, axis={self.axis}, '
f'target_frame={self.target_frame}'
)
if self.reaction_frame is not None:
string += f', reaction_frame={self.reaction_frame})'
else:
string += ')'
return string
class DuffingSpring(ForceActuator):
"""A nonlinear spring based on the Duffing equation.
Explanation
===========
Here, ``DuffingSpring`` represents the force exerted by a nonlinear spring based on the Duffing equation:
F = -beta*x-alpha*x**3, where x is the displacement from the equilibrium position, beta is the linear spring constant,
and alpha is the coefficient for the nonlinear cubic term.
Parameters
==========
linear_stiffness : Expr
The linear stiffness coefficient (beta).
nonlinear_stiffness : Expr
The nonlinear stiffness coefficient (alpha).
pathway : PathwayBase
The pathway that the actuator follows.
equilibrium_length : Expr, optional
The length at which the spring is in equilibrium (x).
"""
def __init__(self, linear_stiffness, nonlinear_stiffness, pathway, equilibrium_length=S.Zero):
self.linear_stiffness = sympify(linear_stiffness, strict=True)
self.nonlinear_stiffness = sympify(nonlinear_stiffness, strict=True)
self.equilibrium_length = sympify(equilibrium_length, strict=True)
if not isinstance(pathway, PathwayBase):
raise TypeError("pathway must be an instance of PathwayBase.")
self._pathway = pathway
@property
def linear_stiffness(self):
return self._linear_stiffness
@linear_stiffness.setter
def linear_stiffness(self, linear_stiffness):
if hasattr(self, '_linear_stiffness'):
msg = (
f'Can\'t set attribute `linear_stiffness` to '
f'{repr(linear_stiffness)} as it is immutable.'
)
raise AttributeError(msg)
self._linear_stiffness = sympify(linear_stiffness, strict=True)
@property
def nonlinear_stiffness(self):
return self._nonlinear_stiffness
@nonlinear_stiffness.setter
def nonlinear_stiffness(self, nonlinear_stiffness):
if hasattr(self, '_nonlinear_stiffness'):
msg = (
f'Can\'t set attribute `nonlinear_stiffness` to '
f'{repr(nonlinear_stiffness)} as it is immutable.'
)
raise AttributeError(msg)
self._nonlinear_stiffness = sympify(nonlinear_stiffness, strict=True)
@property
def pathway(self):
return self._pathway
@pathway.setter
def pathway(self, pathway):
if hasattr(self, '_pathway'):
msg = (
f'Can\'t set attribute `pathway` to {repr(pathway)} as it is '
f'immutable.'
)
raise AttributeError(msg)
if not isinstance(pathway, PathwayBase):
msg = (
f'Value {repr(pathway)} passed to `pathway` was of type '
f'{type(pathway)}, must be {PathwayBase}.'
)
raise TypeError(msg)
self._pathway = pathway
@property
def equilibrium_length(self):
return self._equilibrium_length
@equilibrium_length.setter
def equilibrium_length(self, equilibrium_length):
if hasattr(self, '_equilibrium_length'):
msg = (
f'Can\'t set attribute `equilibrium_length` to '
f'{repr(equilibrium_length)} as it is immutable.'
)
raise AttributeError(msg)
self._equilibrium_length = sympify(equilibrium_length, strict=True)
@property
def force(self):
"""The force produced by the Duffing spring."""
displacement = self.pathway.length - self.equilibrium_length
return -self.linear_stiffness * displacement - self.nonlinear_stiffness * displacement**3
@force.setter
def force(self, force):
if hasattr(self, '_force'):
msg = (
f'Can\'t set attribute `force` to {repr(force)} as it is '
f'immutable.'
)
raise AttributeError(msg)
self._force = sympify(force, strict=True)
def __repr__(self):
return (f"{self.__class__.__name__}("
f"{self.linear_stiffness}, {self.nonlinear_stiffness}, {self.pathway}, "
f"equilibrium_length={self.equilibrium_length})")
PK ]ZZZ���K)` )` sympy/physics/mechanics/body.pyfrom sympy import Symbol
from sympy.physics.vector import Point, Vector, ReferenceFrame, Dyadic
from sympy.physics.mechanics import RigidBody, Particle, Inertia
from sympy.physics.mechanics.body_base import BodyBase
from sympy.utilities.exceptions import sympy_deprecation_warning
__all__ = ['Body']
# XXX: We use type:ignore because the classes RigidBody and Particle have
# inconsistent parallel axis methods that take different numbers of arguments.
class Body(RigidBody, Particle): # type: ignore
"""
Body is a common representation of either a RigidBody or a Particle SymPy
object depending on what is passed in during initialization. If a mass is
passed in and central_inertia is left as None, the Particle object is
created. Otherwise a RigidBody object will be created.
.. deprecated:: 1.13
The Body class is deprecated. Its functionality is captured by
:class:`~.RigidBody` and :class:`~.Particle`.
Explanation
===========
The attributes that Body possesses will be the same as a Particle instance
or a Rigid Body instance depending on which was created. Additional
attributes are listed below.
Attributes
==========
name : string
The body's name
masscenter : Point
The point which represents the center of mass of the rigid body
frame : ReferenceFrame
The reference frame which the body is fixed in
mass : Sympifyable
The body's mass
inertia : (Dyadic, Point)
The body's inertia around its center of mass. This attribute is specific
to the rigid body form of Body and is left undefined for the Particle
form
loads : iterable
This list contains information on the different loads acting on the
Body. Forces are listed as a (point, vector) tuple and torques are
listed as (reference frame, vector) tuples.
Parameters
==========
name : String
Defines the name of the body. It is used as the base for defining
body specific properties.
masscenter : Point, optional
A point that represents the center of mass of the body or particle.
If no point is given, a point is generated.
mass : Sympifyable, optional
A Sympifyable object which represents the mass of the body. If no
mass is passed, one is generated.
frame : ReferenceFrame, optional
The ReferenceFrame that represents the reference frame of the body.
If no frame is given, a frame is generated.
central_inertia : Dyadic, optional
Central inertia dyadic of the body. If none is passed while creating
RigidBody, a default inertia is generated.
Examples
========
As Body has been deprecated, the following examples are for illustrative
purposes only. The functionality of Body is fully captured by
:class:`~.RigidBody` and :class:`~.Particle`. To ignore the deprecation
warning we can use the ignore_warnings context manager.
>>> from sympy.utilities.exceptions import ignore_warnings
Default behaviour. This results in the creation of a RigidBody object for
which the mass, mass center, frame and inertia attributes are given default
values. ::
>>> from sympy.physics.mechanics import Body
>>> with ignore_warnings(DeprecationWarning):
... body = Body('name_of_body')
This next example demonstrates the code required to specify all of the
values of the Body object. Note this will also create a RigidBody version of
the Body object. ::
>>> from sympy import Symbol
>>> from sympy.physics.mechanics import ReferenceFrame, Point, inertia
>>> from sympy.physics.mechanics import Body
>>> mass = Symbol('mass')
>>> masscenter = Point('masscenter')
>>> frame = ReferenceFrame('frame')
>>> ixx = Symbol('ixx')
>>> body_inertia = inertia(frame, ixx, 0, 0)
>>> with ignore_warnings(DeprecationWarning):
... body = Body('name_of_body', masscenter, mass, frame, body_inertia)
The minimal code required to create a Particle version of the Body object
involves simply passing in a name and a mass. ::
>>> from sympy import Symbol
>>> from sympy.physics.mechanics import Body
>>> mass = Symbol('mass')
>>> with ignore_warnings(DeprecationWarning):
... body = Body('name_of_body', mass=mass)
The Particle version of the Body object can also receive a masscenter point
and a reference frame, just not an inertia.
"""
def __init__(self, name, masscenter=None, mass=None, frame=None,
central_inertia=None):
sympy_deprecation_warning(
"""
Support for the Body class has been removed, as its functionality is
fully captured by RigidBody and Particle.
""",
deprecated_since_version="1.13",
active_deprecations_target="deprecated-mechanics-body-class"
)
self._loads = []
if frame is None:
frame = ReferenceFrame(name + '_frame')
if masscenter is None:
masscenter = Point(name + '_masscenter')
if central_inertia is None and mass is None:
ixx = Symbol(name + '_ixx')
iyy = Symbol(name + '_iyy')
izz = Symbol(name + '_izz')
izx = Symbol(name + '_izx')
ixy = Symbol(name + '_ixy')
iyz = Symbol(name + '_iyz')
_inertia = Inertia.from_inertia_scalars(masscenter, frame, ixx, iyy,
izz, ixy, iyz, izx)
else:
_inertia = (central_inertia, masscenter)
if mass is None:
_mass = Symbol(name + '_mass')
else:
_mass = mass
masscenter.set_vel(frame, 0)
# If user passes masscenter and mass then a particle is created
# otherwise a rigidbody. As a result a body may or may not have inertia.
# Note: BodyBase.__init__ is used to prevent problems with super() calls in
# Particle and RigidBody arising due to multiple inheritance.
if central_inertia is None and mass is not None:
BodyBase.__init__(self, name, masscenter, _mass)
self.frame = frame
self._central_inertia = Dyadic(0)
else:
BodyBase.__init__(self, name, masscenter, _mass)
self.frame = frame
self.inertia = _inertia
def __repr__(self):
if self.is_rigidbody:
return RigidBody.__repr__(self)
return Particle.__repr__(self)
@property
def loads(self):
return self._loads
@property
def x(self):
"""The basis Vector for the Body, in the x direction."""
return self.frame.x
@property
def y(self):
"""The basis Vector for the Body, in the y direction."""
return self.frame.y
@property
def z(self):
"""The basis Vector for the Body, in the z direction."""
return self.frame.z
@property
def inertia(self):
"""The body's inertia about a point; stored as (Dyadic, Point)."""
if self.is_rigidbody:
return RigidBody.inertia.fget(self)
return (self.central_inertia, self.masscenter)
@inertia.setter
def inertia(self, I):
RigidBody.inertia.fset(self, I)
@property
def is_rigidbody(self):
if hasattr(self, '_inertia'):
return True
return False
def kinetic_energy(self, frame):
"""Kinetic energy of the body.
Parameters
==========
frame : ReferenceFrame or Body
The Body's angular velocity and the velocity of it's mass
center are typically defined with respect to an inertial frame but
any relevant frame in which the velocities are known can be supplied.
Examples
========
As Body has been deprecated, the following examples are for illustrative
purposes only. The functionality of Body is fully captured by
:class:`~.RigidBody` and :class:`~.Particle`. To ignore the deprecation
warning we can use the ignore_warnings context manager.
>>> from sympy.utilities.exceptions import ignore_warnings
>>> from sympy.physics.mechanics import Body, ReferenceFrame, Point
>>> from sympy import symbols
>>> m, v, r, omega = symbols('m v r omega')
>>> N = ReferenceFrame('N')
>>> O = Point('O')
>>> with ignore_warnings(DeprecationWarning):
... P = Body('P', masscenter=O, mass=m)
>>> P.masscenter.set_vel(N, v * N.y)
>>> P.kinetic_energy(N)
m*v**2/2
>>> N = ReferenceFrame('N')
>>> b = ReferenceFrame('b')
>>> b.set_ang_vel(N, omega * b.x)
>>> P = Point('P')
>>> P.set_vel(N, v * N.x)
>>> with ignore_warnings(DeprecationWarning):
... B = Body('B', masscenter=P, frame=b)
>>> B.kinetic_energy(N)
B_ixx*omega**2/2 + B_mass*v**2/2
See Also
========
sympy.physics.mechanics : Particle, RigidBody
"""
if isinstance(frame, Body):
frame = Body.frame
if self.is_rigidbody:
return RigidBody(self.name, self.masscenter, self.frame, self.mass,
(self.central_inertia, self.masscenter)).kinetic_energy(frame)
return Particle(self.name, self.masscenter, self.mass).kinetic_energy(frame)
def apply_force(self, force, point=None, reaction_body=None, reaction_point=None):
"""Add force to the body(s).
Explanation
===========
Applies the force on self or equal and opposite forces on
self and other body if both are given on the desired point on the bodies.
The force applied on other body is taken opposite of self, i.e, -force.
Parameters
==========
force: Vector
The force to be applied.
point: Point, optional
The point on self on which force is applied.
By default self's masscenter.
reaction_body: Body, optional
Second body on which equal and opposite force
is to be applied.
reaction_point : Point, optional
The point on other body on which equal and opposite
force is applied. By default masscenter of other body.
Example
=======
As Body has been deprecated, the following examples are for illustrative
purposes only. The functionality of Body is fully captured by
:class:`~.RigidBody` and :class:`~.Particle`. To ignore the deprecation
warning we can use the ignore_warnings context manager.
>>> from sympy.utilities.exceptions import ignore_warnings
>>> from sympy import symbols
>>> from sympy.physics.mechanics import Body, Point, dynamicsymbols
>>> m, g = symbols('m g')
>>> with ignore_warnings(DeprecationWarning):
... B = Body('B')
>>> force1 = m*g*B.z
>>> B.apply_force(force1) #Applying force on B's masscenter
>>> B.loads
[(B_masscenter, g*m*B_frame.z)]
We can also remove some part of force from any point on the body by
adding the opposite force to the body on that point.
>>> f1, f2 = dynamicsymbols('f1 f2')
>>> P = Point('P') #Considering point P on body B
>>> B.apply_force(f1*B.x + f2*B.y, P)
>>> B.loads
[(B_masscenter, g*m*B_frame.z), (P, f1(t)*B_frame.x + f2(t)*B_frame.y)]
Let's remove f1 from point P on body B.
>>> B.apply_force(-f1*B.x, P)
>>> B.loads
[(B_masscenter, g*m*B_frame.z), (P, f2(t)*B_frame.y)]
To further demonstrate the use of ``apply_force`` attribute,
consider two bodies connected through a spring.
>>> from sympy.physics.mechanics import Body, dynamicsymbols
>>> with ignore_warnings(DeprecationWarning):
... N = Body('N') #Newtonion Frame
>>> x = dynamicsymbols('x')
>>> with ignore_warnings(DeprecationWarning):
... B1 = Body('B1')
... B2 = Body('B2')
>>> spring_force = x*N.x
Now let's apply equal and opposite spring force to the bodies.
>>> P1 = Point('P1')
>>> P2 = Point('P2')
>>> B1.apply_force(spring_force, point=P1, reaction_body=B2, reaction_point=P2)
We can check the loads(forces) applied to bodies now.
>>> B1.loads
[(P1, x(t)*N_frame.x)]
>>> B2.loads
[(P2, - x(t)*N_frame.x)]
Notes
=====
If a new force is applied to a body on a point which already has some
force applied on it, then the new force is added to the already applied
force on that point.
"""
if not isinstance(point, Point):
if point is None:
point = self.masscenter # masscenter
else:
raise TypeError("Force must be applied to a point on the body.")
if not isinstance(force, Vector):
raise TypeError("Force must be a vector.")
if reaction_body is not None:
reaction_body.apply_force(-force, point=reaction_point)
for load in self._loads:
if point in load:
force += load[1]
self._loads.remove(load)
break
self._loads.append((point, force))
def apply_torque(self, torque, reaction_body=None):
"""Add torque to the body(s).
Explanation
===========
Applies the torque on self or equal and opposite torques on
self and other body if both are given.
The torque applied on other body is taken opposite of self,
i.e, -torque.
Parameters
==========
torque: Vector
The torque to be applied.
reaction_body: Body, optional
Second body on which equal and opposite torque
is to be applied.
Example
=======
As Body has been deprecated, the following examples are for illustrative
purposes only. The functionality of Body is fully captured by
:class:`~.RigidBody` and :class:`~.Particle`. To ignore the deprecation
warning we can use the ignore_warnings context manager.
>>> from sympy.utilities.exceptions import ignore_warnings
>>> from sympy import symbols
>>> from sympy.physics.mechanics import Body, dynamicsymbols
>>> t = symbols('t')
>>> with ignore_warnings(DeprecationWarning):
... B = Body('B')
>>> torque1 = t*B.z
>>> B.apply_torque(torque1)
>>> B.loads
[(B_frame, t*B_frame.z)]
We can also remove some part of torque from the body by
adding the opposite torque to the body.
>>> t1, t2 = dynamicsymbols('t1 t2')
>>> B.apply_torque(t1*B.x + t2*B.y)
>>> B.loads
[(B_frame, t1(t)*B_frame.x + t2(t)*B_frame.y + t*B_frame.z)]
Let's remove t1 from Body B.
>>> B.apply_torque(-t1*B.x)
>>> B.loads
[(B_frame, t2(t)*B_frame.y + t*B_frame.z)]
To further demonstrate the use, let us consider two bodies such that
a torque `T` is acting on one body, and `-T` on the other.
>>> from sympy.physics.mechanics import Body, dynamicsymbols
>>> with ignore_warnings(DeprecationWarning):
... N = Body('N') #Newtonion frame
... B1 = Body('B1')
... B2 = Body('B2')
>>> v = dynamicsymbols('v')
>>> T = v*N.y #Torque
Now let's apply equal and opposite torque to the bodies.
>>> B1.apply_torque(T, B2)
We can check the loads (torques) applied to bodies now.
>>> B1.loads
[(B1_frame, v(t)*N_frame.y)]
>>> B2.loads
[(B2_frame, - v(t)*N_frame.y)]
Notes
=====
If a new torque is applied on body which already has some torque applied on it,
then the new torque is added to the previous torque about the body's frame.
"""
if not isinstance(torque, Vector):
raise TypeError("A Vector must be supplied to add torque.")
if reaction_body is not None:
reaction_body.apply_torque(-torque)
for load in self._loads:
if self.frame in load:
torque += load[1]
self._loads.remove(load)
break
self._loads.append((self.frame, torque))
def clear_loads(self):
"""
Clears the Body's loads list.
Example
=======
As Body has been deprecated, the following examples are for illustrative
purposes only. The functionality of Body is fully captured by
:class:`~.RigidBody` and :class:`~.Particle`. To ignore the deprecation
warning we can use the ignore_warnings context manager.
>>> from sympy.utilities.exceptions import ignore_warnings
>>> from sympy.physics.mechanics import Body
>>> with ignore_warnings(DeprecationWarning):
... B = Body('B')
>>> force = B.x + B.y
>>> B.apply_force(force)
>>> B.loads
[(B_masscenter, B_frame.x + B_frame.y)]
>>> B.clear_loads()
>>> B.loads
[]
"""
self._loads = []
def remove_load(self, about=None):
"""
Remove load about a point or frame.
Parameters
==========
about : Point or ReferenceFrame, optional
The point about which force is applied,
and is to be removed.
If about is None, then the torque about
self's frame is removed.
Example
=======
As Body has been deprecated, the following examples are for illustrative
purposes only. The functionality of Body is fully captured by
:class:`~.RigidBody` and :class:`~.Particle`. To ignore the deprecation
warning we can use the ignore_warnings context manager.
>>> from sympy.utilities.exceptions import ignore_warnings
>>> from sympy.physics.mechanics import Body, Point
>>> with ignore_warnings(DeprecationWarning):
... B = Body('B')
>>> P = Point('P')
>>> f1 = B.x
>>> f2 = B.y
>>> B.apply_force(f1)
>>> B.apply_force(f2, P)
>>> B.loads
[(B_masscenter, B_frame.x), (P, B_frame.y)]
>>> B.remove_load(P)
>>> B.loads
[(B_masscenter, B_frame.x)]
"""
if about is not None:
if not isinstance(about, Point):
raise TypeError('Load is applied about Point or ReferenceFrame.')
else:
about = self.frame
for load in self._loads:
if about in load:
self._loads.remove(load)
break
def masscenter_vel(self, body):
"""
Returns the velocity of the mass center with respect to the provided
rigid body or reference frame.
Parameters
==========
body: Body or ReferenceFrame
The rigid body or reference frame to calculate the velocity in.
Example
=======
As Body has been deprecated, the following examples are for illustrative
purposes only. The functionality of Body is fully captured by
:class:`~.RigidBody` and :class:`~.Particle`. To ignore the deprecation
warning we can use the ignore_warnings context manager.
>>> from sympy.utilities.exceptions import ignore_warnings
>>> from sympy.physics.mechanics import Body
>>> with ignore_warnings(DeprecationWarning):
... A = Body('A')
... B = Body('B')
>>> A.masscenter.set_vel(B.frame, 5*B.frame.x)
>>> A.masscenter_vel(B)
5*B_frame.x
>>> A.masscenter_vel(B.frame)
5*B_frame.x
"""
if isinstance(body, ReferenceFrame):
frame=body
elif isinstance(body, Body):
frame = body.frame
return self.masscenter.vel(frame)
def ang_vel_in(self, body):
"""
Returns this body's angular velocity with respect to the provided
rigid body or reference frame.
Parameters
==========
body: Body or ReferenceFrame
The rigid body or reference frame to calculate the angular velocity in.
Example
=======
As Body has been deprecated, the following examples are for illustrative
purposes only. The functionality of Body is fully captured by
:class:`~.RigidBody` and :class:`~.Particle`. To ignore the deprecation
warning we can use the ignore_warnings context manager.
>>> from sympy.utilities.exceptions import ignore_warnings
>>> from sympy.physics.mechanics import Body, ReferenceFrame
>>> with ignore_warnings(DeprecationWarning):
... A = Body('A')
>>> N = ReferenceFrame('N')
>>> with ignore_warnings(DeprecationWarning):
... B = Body('B', frame=N)
>>> A.frame.set_ang_vel(N, 5*N.x)
>>> A.ang_vel_in(B)
5*N.x
>>> A.ang_vel_in(N)
5*N.x
"""
if isinstance(body, ReferenceFrame):
frame=body
elif isinstance(body, Body):
frame = body.frame
return self.frame.ang_vel_in(frame)
def dcm(self, body):
"""
Returns the direction cosine matrix of this body relative to the
provided rigid body or reference frame.
Parameters
==========
body: Body or ReferenceFrame
The rigid body or reference frame to calculate the dcm.
Example
=======
As Body has been deprecated, the following examples are for illustrative
purposes only. The functionality of Body is fully captured by
:class:`~.RigidBody` and :class:`~.Particle`. To ignore the deprecation
warning we can use the ignore_warnings context manager.
>>> from sympy.utilities.exceptions import ignore_warnings
>>> from sympy.physics.mechanics import Body
>>> with ignore_warnings(DeprecationWarning):
... A = Body('A')
... B = Body('B')
>>> A.frame.orient_axis(B.frame, B.frame.x, 5)
>>> A.dcm(B)
Matrix([
[1, 0, 0],
[0, cos(5), sin(5)],
[0, -sin(5), cos(5)]])
>>> A.dcm(B.frame)
Matrix([
[1, 0, 0],
[0, cos(5), sin(5)],
[0, -sin(5), cos(5)]])
"""
if isinstance(body, ReferenceFrame):
frame=body
elif isinstance(body, Body):
frame = body.frame
return self.frame.dcm(frame)
def parallel_axis(self, point, frame=None):
"""Returns the inertia dyadic of the body with respect to another
point.
Parameters
==========
point : sympy.physics.vector.Point
The point to express the inertia dyadic about.
frame : sympy.physics.vector.ReferenceFrame
The reference frame used to construct the dyadic.
Returns
=======
inertia : sympy.physics.vector.Dyadic
The inertia dyadic of the rigid body expressed about the provided
point.
Example
=======
As Body has been deprecated, the following examples are for illustrative
purposes only. The functionality of Body is fully captured by
:class:`~.RigidBody` and :class:`~.Particle`. To ignore the deprecation
warning we can use the ignore_warnings context manager.
>>> from sympy.utilities.exceptions import ignore_warnings
>>> from sympy.physics.mechanics import Body
>>> with ignore_warnings(DeprecationWarning):
... A = Body('A')
>>> P = A.masscenter.locatenew('point', 3 * A.x + 5 * A.y)
>>> A.parallel_axis(P).to_matrix(A.frame)
Matrix([
[A_ixx + 25*A_mass, A_ixy - 15*A_mass, A_izx],
[A_ixy - 15*A_mass, A_iyy + 9*A_mass, A_iyz],
[ A_izx, A_iyz, A_izz + 34*A_mass]])
"""
if self.is_rigidbody:
return RigidBody.parallel_axis(self, point, frame)
return Particle.parallel_axis(self, point, frame)
PK ]ZZZ��� � $ sympy/physics/mechanics/body_base.pyfrom abc import ABC, abstractmethod
from sympy import Symbol, sympify
from sympy.physics.vector import Point
__all__ = ['BodyBase']
class BodyBase(ABC):
"""Abstract class for body type objects."""
def __init__(self, name, masscenter=None, mass=None):
# Note: If frame=None, no auto-generated frame is created, because a
# Particle does not need to have a frame by default.
if not isinstance(name, str):
raise TypeError('Supply a valid name.')
self._name = name
if mass is None:
mass = Symbol(f'{name}_mass')
if masscenter is None:
masscenter = Point(f'{name}_masscenter')
self.mass = mass
self.masscenter = masscenter
self.potential_energy = 0
self.points = []
def __str__(self):
return self.name
def __repr__(self):
return (f'{self.__class__.__name__}({repr(self.name)}, masscenter='
f'{repr(self.masscenter)}, mass={repr(self.mass)})')
@property
def name(self):
"""The name of the body."""
return self._name
@property
def masscenter(self):
"""The body's center of mass."""
return self._masscenter
@masscenter.setter
def masscenter(self, point):
if not isinstance(point, Point):
raise TypeError("The body's center of mass must be a Point object.")
self._masscenter = point
@property
def mass(self):
"""The body's mass."""
return self._mass
@mass.setter
def mass(self, mass):
self._mass = sympify(mass)
@property
def potential_energy(self):
"""The potential energy of the body.
Examples
========
>>> from sympy.physics.mechanics import Particle, Point
>>> from sympy import symbols
>>> m, g, h = symbols('m g h')
>>> O = Point('O')
>>> P = Particle('P', O, m)
>>> P.potential_energy = m * g * h
>>> P.potential_energy
g*h*m
"""
return self._potential_energy
@potential_energy.setter
def potential_energy(self, scalar):
self._potential_energy = sympify(scalar)
@abstractmethod
def kinetic_energy(self, frame):
pass
@abstractmethod
def linear_momentum(self, frame):
pass
@abstractmethod
def angular_momentum(self, point, frame):
pass
@abstractmethod
def parallel_axis(self, point, frame):
pass
PK ]ZZZ��nfb fb $ sympy/physics/mechanics/functions.pyfrom sympy.utilities import dict_merge
from sympy.utilities.iterables import iterable
from sympy.physics.vector import (Dyadic, Vector, ReferenceFrame,
Point, dynamicsymbols)
from sympy.physics.vector.printing import (vprint, vsprint, vpprint, vlatex,
init_vprinting)
from sympy.physics.mechanics.particle import Particle
from sympy.physics.mechanics.rigidbody import RigidBody
from sympy.simplify.simplify import simplify
from sympy import Matrix, Mul, Derivative, sin, cos, tan, S
from sympy.core.function import AppliedUndef
from sympy.physics.mechanics.inertia import (inertia as _inertia,
inertia_of_point_mass as _inertia_of_point_mass)
from sympy.utilities.exceptions import sympy_deprecation_warning
__all__ = ['linear_momentum',
'angular_momentum',
'kinetic_energy',
'potential_energy',
'Lagrangian',
'mechanics_printing',
'mprint',
'msprint',
'mpprint',
'mlatex',
'msubs',
'find_dynamicsymbols']
# These are functions that we've moved and renamed during extracting the
# basic vector calculus code from the mechanics packages.
mprint = vprint
msprint = vsprint
mpprint = vpprint
mlatex = vlatex
def mechanics_printing(**kwargs):
"""
Initializes time derivative printing for all SymPy objects in
mechanics module.
"""
init_vprinting(**kwargs)
mechanics_printing.__doc__ = init_vprinting.__doc__
def inertia(frame, ixx, iyy, izz, ixy=0, iyz=0, izx=0):
sympy_deprecation_warning(
"""
The inertia function has been moved.
Import it from "sympy.physics.mechanics".
""",
deprecated_since_version="1.13",
active_deprecations_target="moved-mechanics-functions"
)
return _inertia(frame, ixx, iyy, izz, ixy, iyz, izx)
def inertia_of_point_mass(mass, pos_vec, frame):
sympy_deprecation_warning(
"""
The inertia_of_point_mass function has been moved.
Import it from "sympy.physics.mechanics".
""",
deprecated_since_version="1.13",
active_deprecations_target="moved-mechanics-functions"
)
return _inertia_of_point_mass(mass, pos_vec, frame)
def linear_momentum(frame, *body):
"""Linear momentum of the system.
Explanation
===========
This function returns the linear momentum of a system of Particle's and/or
RigidBody's. The linear momentum of a system is equal to the vector sum of
the linear momentum of its constituents. Consider a system, S, comprised of
a rigid body, A, and a particle, P. The linear momentum of the system, L,
is equal to the vector sum of the linear momentum of the particle, L1, and
the linear momentum of the rigid body, L2, i.e.
L = L1 + L2
Parameters
==========
frame : ReferenceFrame
The frame in which linear momentum is desired.
body1, body2, body3... : Particle and/or RigidBody
The body (or bodies) whose linear momentum is required.
Examples
========
>>> from sympy.physics.mechanics import Point, Particle, ReferenceFrame
>>> from sympy.physics.mechanics import RigidBody, outer, linear_momentum
>>> N = ReferenceFrame('N')
>>> P = Point('P')
>>> P.set_vel(N, 10 * N.x)
>>> Pa = Particle('Pa', P, 1)
>>> Ac = Point('Ac')
>>> Ac.set_vel(N, 25 * N.y)
>>> I = outer(N.x, N.x)
>>> A = RigidBody('A', Ac, N, 20, (I, Ac))
>>> linear_momentum(N, A, Pa)
10*N.x + 500*N.y
"""
if not isinstance(frame, ReferenceFrame):
raise TypeError('Please specify a valid ReferenceFrame')
else:
linear_momentum_sys = Vector(0)
for e in body:
if isinstance(e, (RigidBody, Particle)):
linear_momentum_sys += e.linear_momentum(frame)
else:
raise TypeError('*body must have only Particle or RigidBody')
return linear_momentum_sys
def angular_momentum(point, frame, *body):
"""Angular momentum of a system.
Explanation
===========
This function returns the angular momentum of a system of Particle's and/or
RigidBody's. The angular momentum of such a system is equal to the vector
sum of the angular momentum of its constituents. Consider a system, S,
comprised of a rigid body, A, and a particle, P. The angular momentum of
the system, H, is equal to the vector sum of the angular momentum of the
particle, H1, and the angular momentum of the rigid body, H2, i.e.
H = H1 + H2
Parameters
==========
point : Point
The point about which angular momentum of the system is desired.
frame : ReferenceFrame
The frame in which angular momentum is desired.
body1, body2, body3... : Particle and/or RigidBody
The body (or bodies) whose angular momentum is required.
Examples
========
>>> from sympy.physics.mechanics import Point, Particle, ReferenceFrame
>>> from sympy.physics.mechanics import RigidBody, outer, angular_momentum
>>> N = ReferenceFrame('N')
>>> O = Point('O')
>>> O.set_vel(N, 0 * N.x)
>>> P = O.locatenew('P', 1 * N.x)
>>> P.set_vel(N, 10 * N.x)
>>> Pa = Particle('Pa', P, 1)
>>> Ac = O.locatenew('Ac', 2 * N.y)
>>> Ac.set_vel(N, 5 * N.y)
>>> a = ReferenceFrame('a')
>>> a.set_ang_vel(N, 10 * N.z)
>>> I = outer(N.z, N.z)
>>> A = RigidBody('A', Ac, a, 20, (I, Ac))
>>> angular_momentum(O, N, Pa, A)
10*N.z
"""
if not isinstance(frame, ReferenceFrame):
raise TypeError('Please enter a valid ReferenceFrame')
if not isinstance(point, Point):
raise TypeError('Please specify a valid Point')
else:
angular_momentum_sys = Vector(0)
for e in body:
if isinstance(e, (RigidBody, Particle)):
angular_momentum_sys += e.angular_momentum(point, frame)
else:
raise TypeError('*body must have only Particle or RigidBody')
return angular_momentum_sys
def kinetic_energy(frame, *body):
"""Kinetic energy of a multibody system.
Explanation
===========
This function returns the kinetic energy of a system of Particle's and/or
RigidBody's. The kinetic energy of such a system is equal to the sum of
the kinetic energies of its constituents. Consider a system, S, comprising
a rigid body, A, and a particle, P. The kinetic energy of the system, T,
is equal to the vector sum of the kinetic energy of the particle, T1, and
the kinetic energy of the rigid body, T2, i.e.
T = T1 + T2
Kinetic energy is a scalar.
Parameters
==========
frame : ReferenceFrame
The frame in which the velocity or angular velocity of the body is
defined.
body1, body2, body3... : Particle and/or RigidBody
The body (or bodies) whose kinetic energy is required.
Examples
========
>>> from sympy.physics.mechanics import Point, Particle, ReferenceFrame
>>> from sympy.physics.mechanics import RigidBody, outer, kinetic_energy
>>> N = ReferenceFrame('N')
>>> O = Point('O')
>>> O.set_vel(N, 0 * N.x)
>>> P = O.locatenew('P', 1 * N.x)
>>> P.set_vel(N, 10 * N.x)
>>> Pa = Particle('Pa', P, 1)
>>> Ac = O.locatenew('Ac', 2 * N.y)
>>> Ac.set_vel(N, 5 * N.y)
>>> a = ReferenceFrame('a')
>>> a.set_ang_vel(N, 10 * N.z)
>>> I = outer(N.z, N.z)
>>> A = RigidBody('A', Ac, a, 20, (I, Ac))
>>> kinetic_energy(N, Pa, A)
350
"""
if not isinstance(frame, ReferenceFrame):
raise TypeError('Please enter a valid ReferenceFrame')
ke_sys = S.Zero
for e in body:
if isinstance(e, (RigidBody, Particle)):
ke_sys += e.kinetic_energy(frame)
else:
raise TypeError('*body must have only Particle or RigidBody')
return ke_sys
def potential_energy(*body):
"""Potential energy of a multibody system.
Explanation
===========
This function returns the potential energy of a system of Particle's and/or
RigidBody's. The potential energy of such a system is equal to the sum of
the potential energy of its constituents. Consider a system, S, comprising
a rigid body, A, and a particle, P. The potential energy of the system, V,
is equal to the vector sum of the potential energy of the particle, V1, and
the potential energy of the rigid body, V2, i.e.
V = V1 + V2
Potential energy is a scalar.
Parameters
==========
body1, body2, body3... : Particle and/or RigidBody
The body (or bodies) whose potential energy is required.
Examples
========
>>> from sympy.physics.mechanics import Point, Particle, ReferenceFrame
>>> from sympy.physics.mechanics import RigidBody, outer, potential_energy
>>> from sympy import symbols
>>> M, m, g, h = symbols('M m g h')
>>> N = ReferenceFrame('N')
>>> O = Point('O')
>>> O.set_vel(N, 0 * N.x)
>>> P = O.locatenew('P', 1 * N.x)
>>> Pa = Particle('Pa', P, m)
>>> Ac = O.locatenew('Ac', 2 * N.y)
>>> a = ReferenceFrame('a')
>>> I = outer(N.z, N.z)
>>> A = RigidBody('A', Ac, a, M, (I, Ac))
>>> Pa.potential_energy = m * g * h
>>> A.potential_energy = M * g * h
>>> potential_energy(Pa, A)
M*g*h + g*h*m
"""
pe_sys = S.Zero
for e in body:
if isinstance(e, (RigidBody, Particle)):
pe_sys += e.potential_energy
else:
raise TypeError('*body must have only Particle or RigidBody')
return pe_sys
def gravity(acceleration, *bodies):
from sympy.physics.mechanics.loads import gravity as _gravity
sympy_deprecation_warning(
"""
The gravity function has been moved.
Import it from "sympy.physics.mechanics.loads".
""",
deprecated_since_version="1.13",
active_deprecations_target="moved-mechanics-functions"
)
return _gravity(acceleration, *bodies)
def center_of_mass(point, *bodies):
"""
Returns the position vector from the given point to the center of mass
of the given bodies(particles or rigidbodies).
Example
=======
>>> from sympy import symbols, S
>>> from sympy.physics.vector import Point
>>> from sympy.physics.mechanics import Particle, ReferenceFrame, RigidBody, outer
>>> from sympy.physics.mechanics.functions import center_of_mass
>>> a = ReferenceFrame('a')
>>> m = symbols('m', real=True)
>>> p1 = Particle('p1', Point('p1_pt'), S(1))
>>> p2 = Particle('p2', Point('p2_pt'), S(2))
>>> p3 = Particle('p3', Point('p3_pt'), S(3))
>>> p4 = Particle('p4', Point('p4_pt'), m)
>>> b_f = ReferenceFrame('b_f')
>>> b_cm = Point('b_cm')
>>> mb = symbols('mb')
>>> b = RigidBody('b', b_cm, b_f, mb, (outer(b_f.x, b_f.x), b_cm))
>>> p2.point.set_pos(p1.point, a.x)
>>> p3.point.set_pos(p1.point, a.x + a.y)
>>> p4.point.set_pos(p1.point, a.y)
>>> b.masscenter.set_pos(p1.point, a.y + a.z)
>>> point_o=Point('o')
>>> point_o.set_pos(p1.point, center_of_mass(p1.point, p1, p2, p3, p4, b))
>>> expr = 5/(m + mb + 6)*a.x + (m + mb + 3)/(m + mb + 6)*a.y + mb/(m + mb + 6)*a.z
>>> point_o.pos_from(p1.point)
5/(m + mb + 6)*a.x + (m + mb + 3)/(m + mb + 6)*a.y + mb/(m + mb + 6)*a.z
"""
if not bodies:
raise TypeError("No bodies(instances of Particle or Rigidbody) were passed.")
total_mass = 0
vec = Vector(0)
for i in bodies:
total_mass += i.mass
masscenter = getattr(i, 'masscenter', None)
if masscenter is None:
masscenter = i.point
vec += i.mass*masscenter.pos_from(point)
return vec/total_mass
def Lagrangian(frame, *body):
"""Lagrangian of a multibody system.
Explanation
===========
This function returns the Lagrangian of a system of Particle's and/or
RigidBody's. The Lagrangian of such a system is equal to the difference
between the kinetic energies and potential energies of its constituents. If
T and V are the kinetic and potential energies of a system then it's
Lagrangian, L, is defined as
L = T - V
The Lagrangian is a scalar.
Parameters
==========
frame : ReferenceFrame
The frame in which the velocity or angular velocity of the body is
defined to determine the kinetic energy.
body1, body2, body3... : Particle and/or RigidBody
The body (or bodies) whose Lagrangian is required.
Examples
========
>>> from sympy.physics.mechanics import Point, Particle, ReferenceFrame
>>> from sympy.physics.mechanics import RigidBody, outer, Lagrangian
>>> from sympy import symbols
>>> M, m, g, h = symbols('M m g h')
>>> N = ReferenceFrame('N')
>>> O = Point('O')
>>> O.set_vel(N, 0 * N.x)
>>> P = O.locatenew('P', 1 * N.x)
>>> P.set_vel(N, 10 * N.x)
>>> Pa = Particle('Pa', P, 1)
>>> Ac = O.locatenew('Ac', 2 * N.y)
>>> Ac.set_vel(N, 5 * N.y)
>>> a = ReferenceFrame('a')
>>> a.set_ang_vel(N, 10 * N.z)
>>> I = outer(N.z, N.z)
>>> A = RigidBody('A', Ac, a, 20, (I, Ac))
>>> Pa.potential_energy = m * g * h
>>> A.potential_energy = M * g * h
>>> Lagrangian(N, Pa, A)
-M*g*h - g*h*m + 350
"""
if not isinstance(frame, ReferenceFrame):
raise TypeError('Please supply a valid ReferenceFrame')
for e in body:
if not isinstance(e, (RigidBody, Particle)):
raise TypeError('*body must have only Particle or RigidBody')
return kinetic_energy(frame, *body) - potential_energy(*body)
def find_dynamicsymbols(expression, exclude=None, reference_frame=None):
"""Find all dynamicsymbols in expression.
Explanation
===========
If the optional ``exclude`` kwarg is used, only dynamicsymbols
not in the iterable ``exclude`` are returned.
If we intend to apply this function on a vector, the optional
``reference_frame`` is also used to inform about the corresponding frame
with respect to which the dynamic symbols of the given vector is to be
determined.
Parameters
==========
expression : SymPy expression
exclude : iterable of dynamicsymbols, optional
reference_frame : ReferenceFrame, optional
The frame with respect to which the dynamic symbols of the
given vector is to be determined.
Examples
========
>>> from sympy.physics.mechanics import dynamicsymbols, find_dynamicsymbols
>>> from sympy.physics.mechanics import ReferenceFrame
>>> x, y = dynamicsymbols('x, y')
>>> expr = x + x.diff()*y
>>> find_dynamicsymbols(expr)
{x(t), y(t), Derivative(x(t), t)}
>>> find_dynamicsymbols(expr, exclude=[x, y])
{Derivative(x(t), t)}
>>> a, b, c = dynamicsymbols('a, b, c')
>>> A = ReferenceFrame('A')
>>> v = a * A.x + b * A.y + c * A.z
>>> find_dynamicsymbols(v, reference_frame=A)
{a(t), b(t), c(t)}
"""
t_set = {dynamicsymbols._t}
if exclude:
if iterable(exclude):
exclude_set = set(exclude)
else:
raise TypeError("exclude kwarg must be iterable")
else:
exclude_set = set()
if isinstance(expression, Vector):
if reference_frame is None:
raise ValueError("You must provide reference_frame when passing a "
"vector expression, got %s." % reference_frame)
else:
expression = expression.to_matrix(reference_frame)
return {i for i in expression.atoms(AppliedUndef, Derivative) if
i.free_symbols == t_set} - exclude_set
def msubs(expr, *sub_dicts, smart=False, **kwargs):
"""A custom subs for use on expressions derived in physics.mechanics.
Traverses the expression tree once, performing the subs found in sub_dicts.
Terms inside ``Derivative`` expressions are ignored:
Examples
========
>>> from sympy.physics.mechanics import dynamicsymbols, msubs
>>> x = dynamicsymbols('x')
>>> msubs(x.diff() + x, {x: 1})
Derivative(x(t), t) + 1
Note that sub_dicts can be a single dictionary, or several dictionaries:
>>> x, y, z = dynamicsymbols('x, y, z')
>>> sub1 = {x: 1, y: 2}
>>> sub2 = {z: 3, x.diff(): 4}
>>> msubs(x.diff() + x + y + z, sub1, sub2)
10
If smart=True (default False), also checks for conditions that may result
in ``nan``, but if simplified would yield a valid expression. For example:
>>> from sympy import sin, tan
>>> (sin(x)/tan(x)).subs(x, 0)
nan
>>> msubs(sin(x)/tan(x), {x: 0}, smart=True)
1
It does this by first replacing all ``tan`` with ``sin/cos``. Then each
node is traversed. If the node is a fraction, subs is first evaluated on
the denominator. If this results in 0, simplification of the entire
fraction is attempted. Using this selective simplification, only
subexpressions that result in 1/0 are targeted, resulting in faster
performance.
"""
sub_dict = dict_merge(*sub_dicts)
if smart:
func = _smart_subs
elif hasattr(expr, 'msubs'):
return expr.msubs(sub_dict)
else:
func = lambda expr, sub_dict: _crawl(expr, _sub_func, sub_dict)
if isinstance(expr, (Matrix, Vector, Dyadic)):
return expr.applyfunc(lambda x: func(x, sub_dict))
else:
return func(expr, sub_dict)
def _crawl(expr, func, *args, **kwargs):
"""Crawl the expression tree, and apply func to every node."""
val = func(expr, *args, **kwargs)
if val is not None:
return val
new_args = (_crawl(arg, func, *args, **kwargs) for arg in expr.args)
return expr.func(*new_args)
def _sub_func(expr, sub_dict):
"""Perform direct matching substitution, ignoring derivatives."""
if expr in sub_dict:
return sub_dict[expr]
elif not expr.args or expr.is_Derivative:
return expr
def _tan_repl_func(expr):
"""Replace tan with sin/cos."""
if isinstance(expr, tan):
return sin(*expr.args) / cos(*expr.args)
elif not expr.args or expr.is_Derivative:
return expr
def _smart_subs(expr, sub_dict):
"""Performs subs, checking for conditions that may result in `nan` or
`oo`, and attempts to simplify them out.
The expression tree is traversed twice, and the following steps are
performed on each expression node:
- First traverse:
Replace all `tan` with `sin/cos`.
- Second traverse:
If node is a fraction, check if the denominator evaluates to 0.
If so, attempt to simplify it out. Then if node is in sub_dict,
sub in the corresponding value.
"""
expr = _crawl(expr, _tan_repl_func)
def _recurser(expr, sub_dict):
# Decompose the expression into num, den
num, den = _fraction_decomp(expr)
if den != 1:
# If there is a non trivial denominator, we need to handle it
denom_subbed = _recurser(den, sub_dict)
if denom_subbed.evalf() == 0:
# If denom is 0 after this, attempt to simplify the bad expr
expr = simplify(expr)
else:
# Expression won't result in nan, find numerator
num_subbed = _recurser(num, sub_dict)
return num_subbed / denom_subbed
# We have to crawl the tree manually, because `expr` may have been
# modified in the simplify step. First, perform subs as normal:
val = _sub_func(expr, sub_dict)
if val is not None:
return val
new_args = (_recurser(arg, sub_dict) for arg in expr.args)
return expr.func(*new_args)
return _recurser(expr, sub_dict)
def _fraction_decomp(expr):
"""Return num, den such that expr = num/den."""
if not isinstance(expr, Mul):
return expr, 1
num = []
den = []
for a in expr.args:
if a.is_Pow and a.args[1] < 0:
den.append(1 / a)
else:
num.append(a)
if not den:
return expr, 1
num = Mul(*num)
den = Mul(*den)
return num, den
def _f_list_parser(fl, ref_frame):
"""Parses the provided forcelist composed of items
of the form (obj, force).
Returns a tuple containing:
vel_list: The velocity (ang_vel for Frames, vel for Points) in
the provided reference frame.
f_list: The forces.
Used internally in the KanesMethod and LagrangesMethod classes.
"""
def flist_iter():
for pair in fl:
obj, force = pair
if isinstance(obj, ReferenceFrame):
yield obj.ang_vel_in(ref_frame), force
elif isinstance(obj, Point):
yield obj.vel(ref_frame), force
else:
raise TypeError('First entry in each forcelist pair must '
'be a point or frame.')
if not fl:
vel_list, f_list = (), ()
else:
unzip = lambda l: list(zip(*l)) if l[0] else [(), ()]
vel_list, f_list = unzip(list(flist_iter()))
return vel_list, f_list
def _validate_coordinates(coordinates=None, speeds=None, check_duplicates=True,
is_dynamicsymbols=True, u_auxiliary=None):
"""Validate the generalized coordinates and generalized speeds.
Parameters
==========
coordinates : iterable, optional
Generalized coordinates to be validated.
speeds : iterable, optional
Generalized speeds to be validated.
check_duplicates : bool, optional
Checks if there are duplicates in the generalized coordinates and
generalized speeds. If so it will raise a ValueError. The default is
True.
is_dynamicsymbols : iterable, optional
Checks if all the generalized coordinates and generalized speeds are
dynamicsymbols. If any is not a dynamicsymbol, a ValueError will be
raised. The default is True.
u_auxiliary : iterable, optional
Auxiliary generalized speeds to be validated.
"""
t_set = {dynamicsymbols._t}
# Convert input to iterables
if coordinates is None:
coordinates = []
elif not iterable(coordinates):
coordinates = [coordinates]
if speeds is None:
speeds = []
elif not iterable(speeds):
speeds = [speeds]
if u_auxiliary is None:
u_auxiliary = []
elif not iterable(u_auxiliary):
u_auxiliary = [u_auxiliary]
msgs = []
if check_duplicates: # Check for duplicates
seen = set()
coord_duplicates = {x for x in coordinates if x in seen or seen.add(x)}
seen = set()
speed_duplicates = {x for x in speeds if x in seen or seen.add(x)}
seen = set()
aux_duplicates = {x for x in u_auxiliary if x in seen or seen.add(x)}
overlap_coords = set(coordinates).intersection(speeds)
overlap_aux = set(coordinates).union(speeds).intersection(u_auxiliary)
if coord_duplicates:
msgs.append(f'The generalized coordinates {coord_duplicates} are '
f'duplicated, all generalized coordinates should be '
f'unique.')
if speed_duplicates:
msgs.append(f'The generalized speeds {speed_duplicates} are '
f'duplicated, all generalized speeds should be unique.')
if aux_duplicates:
msgs.append(f'The auxiliary speeds {aux_duplicates} are duplicated,'
f' all auxiliary speeds should be unique.')
if overlap_coords:
msgs.append(f'{overlap_coords} are defined as both generalized '
f'coordinates and generalized speeds.')
if overlap_aux:
msgs.append(f'The auxiliary speeds {overlap_aux} are also defined '
f'as generalized coordinates or generalized speeds.')
if is_dynamicsymbols: # Check whether all coordinates are dynamicsymbols
for coordinate in coordinates:
if not (isinstance(coordinate, (AppliedUndef, Derivative)) and
coordinate.free_symbols == t_set):
msgs.append(f'Generalized coordinate "{coordinate}" is not a '
f'dynamicsymbol.')
for speed in speeds:
if not (isinstance(speed, (AppliedUndef, Derivative)) and
speed.free_symbols == t_set):
msgs.append(
f'Generalized speed "{speed}" is not a dynamicsymbol.')
for aux in u_auxiliary:
if not (isinstance(aux, (AppliedUndef, Derivative)) and
aux.free_symbols == t_set):
msgs.append(
f'Auxiliary speed "{aux}" is not a dynamicsymbol.')
if msgs:
raise ValueError('\n'.join(msgs))
def _parse_linear_solver(linear_solver):
"""Helper function to retrieve a specified linear solver."""
if callable(linear_solver):
return linear_solver
return lambda A, b: Matrix.solve(A, b, method=linear_solver)
PK ]ZZZ��T " sympy/physics/mechanics/inertia.pyfrom sympy import sympify
from sympy.physics.vector import Point, Dyadic, ReferenceFrame, outer
from collections import namedtuple
__all__ = ['inertia', 'inertia_of_point_mass', 'Inertia']
def inertia(frame, ixx, iyy, izz, ixy=0, iyz=0, izx=0):
"""Simple way to create inertia Dyadic object.
Explanation
===========
Creates an inertia Dyadic based on the given tensor values and a body-fixed
reference frame.
Parameters
==========
frame : ReferenceFrame
The frame the inertia is defined in.
ixx : Sympifyable
The xx element in the inertia dyadic.
iyy : Sympifyable
The yy element in the inertia dyadic.
izz : Sympifyable
The zz element in the inertia dyadic.
ixy : Sympifyable
The xy element in the inertia dyadic.
iyz : Sympifyable
The yz element in the inertia dyadic.
izx : Sympifyable
The zx element in the inertia dyadic.
Examples
========
>>> from sympy.physics.mechanics import ReferenceFrame, inertia
>>> N = ReferenceFrame('N')
>>> inertia(N, 1, 2, 3)
(N.x|N.x) + 2*(N.y|N.y) + 3*(N.z|N.z)
"""
if not isinstance(frame, ReferenceFrame):
raise TypeError('Need to define the inertia in a frame')
ixx, iyy, izz = sympify(ixx), sympify(iyy), sympify(izz)
ixy, iyz, izx = sympify(ixy), sympify(iyz), sympify(izx)
return (ixx*outer(frame.x, frame.x) + ixy*outer(frame.x, frame.y) +
izx*outer(frame.x, frame.z) + ixy*outer(frame.y, frame.x) +
iyy*outer(frame.y, frame.y) + iyz*outer(frame.y, frame.z) +
izx*outer(frame.z, frame.x) + iyz*outer(frame.z, frame.y) +
izz*outer(frame.z, frame.z))
def inertia_of_point_mass(mass, pos_vec, frame):
"""Inertia dyadic of a point mass relative to point O.
Parameters
==========
mass : Sympifyable
Mass of the point mass
pos_vec : Vector
Position from point O to point mass
frame : ReferenceFrame
Reference frame to express the dyadic in
Examples
========
>>> from sympy import symbols
>>> from sympy.physics.mechanics import ReferenceFrame, inertia_of_point_mass
>>> N = ReferenceFrame('N')
>>> r, m = symbols('r m')
>>> px = r * N.x
>>> inertia_of_point_mass(m, px, N)
m*r**2*(N.y|N.y) + m*r**2*(N.z|N.z)
"""
return mass*(
(outer(frame.x, frame.x) +
outer(frame.y, frame.y) +
outer(frame.z, frame.z)) *
(pos_vec.dot(pos_vec)) - outer(pos_vec, pos_vec))
class Inertia(namedtuple('Inertia', ['dyadic', 'point'])):
"""Inertia object consisting of a Dyadic and a Point of reference.
Explanation
===========
This is a simple class to store the Point and Dyadic, belonging to an
inertia.
Attributes
==========
dyadic : Dyadic
The dyadic of the inertia.
point : Point
The reference point of the inertia.
Examples
========
>>> from sympy.physics.mechanics import ReferenceFrame, Point, Inertia
>>> N = ReferenceFrame('N')
>>> Po = Point('Po')
>>> Inertia(N.x.outer(N.x) + N.y.outer(N.y) + N.z.outer(N.z), Po)
((N.x|N.x) + (N.y|N.y) + (N.z|N.z), Po)
In the example above the Dyadic was created manually, one can however also
use the ``inertia`` function for this or the class method ``from_tensor`` as
shown below.
>>> Inertia.from_inertia_scalars(Po, N, 1, 1, 1)
((N.x|N.x) + (N.y|N.y) + (N.z|N.z), Po)
"""
def __new__(cls, dyadic, point):
# Switch order if given in the wrong order
if isinstance(dyadic, Point) and isinstance(point, Dyadic):
point, dyadic = dyadic, point
if not isinstance(point, Point):
raise TypeError('Reference point should be of type Point')
if not isinstance(dyadic, Dyadic):
raise TypeError('Inertia value should be expressed as a Dyadic')
return super().__new__(cls, dyadic, point)
@classmethod
def from_inertia_scalars(cls, point, frame, ixx, iyy, izz, ixy=0, iyz=0,
izx=0):
"""Simple way to create an Inertia object based on the tensor values.
Explanation
===========
This class method uses the :func`~.inertia` to create the Dyadic based
on the tensor values.
Parameters
==========
point : Point
The reference point of the inertia.
frame : ReferenceFrame
The frame the inertia is defined in.
ixx : Sympifyable
The xx element in the inertia dyadic.
iyy : Sympifyable
The yy element in the inertia dyadic.
izz : Sympifyable
The zz element in the inertia dyadic.
ixy : Sympifyable
The xy element in the inertia dyadic.
iyz : Sympifyable
The yz element in the inertia dyadic.
izx : Sympifyable
The zx element in the inertia dyadic.
Examples
========
>>> from sympy import symbols
>>> from sympy.physics.mechanics import ReferenceFrame, Point, Inertia
>>> ixx, iyy, izz, ixy, iyz, izx = symbols('ixx iyy izz ixy iyz izx')
>>> N = ReferenceFrame('N')
>>> P = Point('P')
>>> I = Inertia.from_inertia_scalars(P, N, ixx, iyy, izz, ixy, iyz, izx)
The tensor values can easily be seen when converting the dyadic to a
matrix.
>>> I.dyadic.to_matrix(N)
Matrix([
[ixx, ixy, izx],
[ixy, iyy, iyz],
[izx, iyz, izz]])
"""
return cls(inertia(frame, ixx, iyy, izz, ixy, iyz, izx), point)
def __add__(self, other):
raise TypeError(f"unsupported operand type(s) for +: "
f"'{self.__class__.__name__}' and "
f"'{other.__class__.__name__}'")
def __mul__(self, other):
raise TypeError(f"unsupported operand type(s) for *: "
f"'{self.__class__.__name__}' and "
f"'{other.__class__.__name__}'")
__radd__ = __add__
__rmul__ = __mul__
PK ]ZZZ���'eK eK sympy/physics/mechanics/joint.py# coding=utf-8
from abc import ABC, abstractmethod
from sympy import pi, Derivative, Matrix
from sympy.core.function import AppliedUndef
from sympy.physics.mechanics.body_base import BodyBase
from sympy.physics.mechanics.functions import _validate_coordinates
from sympy.physics.vector import (Vector, dynamicsymbols, cross, Point,
ReferenceFrame)
from sympy.utilities.iterables import iterable
from sympy.utilities.exceptions import sympy_deprecation_warning
__all__ = ['Joint', 'PinJoint', 'PrismaticJoint', 'CylindricalJoint',
'PlanarJoint', 'SphericalJoint', 'WeldJoint']
class Joint(ABC):
"""Abstract base class for all specific joints.
Explanation
===========
A joint subtracts degrees of freedom from a body. This is the base class
for all specific joints and holds all common methods acting as an interface
for all joints. Custom joint can be created by inheriting Joint class and
defining all abstract functions.
The abstract methods are:
- ``_generate_coordinates``
- ``_generate_speeds``
- ``_orient_frames``
- ``_set_angular_velocity``
- ``_set_linear_velocity``
Parameters
==========
name : string
A unique name for the joint.
parent : Particle or RigidBody or Body
The parent body of joint.
child : Particle or RigidBody or Body
The child body of joint.
coordinates : iterable of dynamicsymbols, optional
Generalized coordinates of the joint.
speeds : iterable of dynamicsymbols, optional
Generalized speeds of joint.
parent_point : Point or Vector, optional
Attachment point where the joint is fixed to the parent body. If a
vector is provided, then the attachment point is computed by adding the
vector to the body's mass center. The default value is the parent's mass
center.
child_point : Point or Vector, optional
Attachment point where the joint is fixed to the child body. If a
vector is provided, then the attachment point is computed by adding the
vector to the body's mass center. The default value is the child's mass
center.
parent_axis : Vector, optional
.. deprecated:: 1.12
Axis fixed in the parent body which aligns with an axis fixed in the
child body. The default is the x axis of parent's reference frame.
For more information on this deprecation, see
:ref:`deprecated-mechanics-joint-axis`.
child_axis : Vector, optional
.. deprecated:: 1.12
Axis fixed in the child body which aligns with an axis fixed in the
parent body. The default is the x axis of child's reference frame.
For more information on this deprecation, see
:ref:`deprecated-mechanics-joint-axis`.
parent_interframe : ReferenceFrame, optional
Intermediate frame of the parent body with respect to which the joint
transformation is formulated. If a Vector is provided then an interframe
is created which aligns its X axis with the given vector. The default
value is the parent's own frame.
child_interframe : ReferenceFrame, optional
Intermediate frame of the child body with respect to which the joint
transformation is formulated. If a Vector is provided then an interframe
is created which aligns its X axis with the given vector. The default
value is the child's own frame.
parent_joint_pos : Point or Vector, optional
.. deprecated:: 1.12
This argument is replaced by parent_point and will be removed in a
future version.
See :ref:`deprecated-mechanics-joint-pos` for more information.
child_joint_pos : Point or Vector, optional
.. deprecated:: 1.12
This argument is replaced by child_point and will be removed in a
future version.
See :ref:`deprecated-mechanics-joint-pos` for more information.
Attributes
==========
name : string
The joint's name.
parent : Particle or RigidBody or Body
The joint's parent body.
child : Particle or RigidBody or Body
The joint's child body.
coordinates : Matrix
Matrix of the joint's generalized coordinates.
speeds : Matrix
Matrix of the joint's generalized speeds.
parent_point : Point
Attachment point where the joint is fixed to the parent body.
child_point : Point
Attachment point where the joint is fixed to the child body.
parent_axis : Vector
The axis fixed in the parent frame that represents the joint.
child_axis : Vector
The axis fixed in the child frame that represents the joint.
parent_interframe : ReferenceFrame
Intermediate frame of the parent body with respect to which the joint
transformation is formulated.
child_interframe : ReferenceFrame
Intermediate frame of the child body with respect to which the joint
transformation is formulated.
kdes : Matrix
Kinematical differential equations of the joint.
Notes
=====
When providing a vector as the intermediate frame, a new intermediate frame
is created which aligns its X axis with the provided vector. This is done
with a single fixed rotation about a rotation axis. This rotation axis is
determined by taking the cross product of the ``body.x`` axis with the
provided vector. In the case where the provided vector is in the ``-body.x``
direction, the rotation is done about the ``body.y`` axis.
"""
def __init__(self, name, parent, child, coordinates=None, speeds=None,
parent_point=None, child_point=None, parent_interframe=None,
child_interframe=None, parent_axis=None, child_axis=None,
parent_joint_pos=None, child_joint_pos=None):
if not isinstance(name, str):
raise TypeError('Supply a valid name.')
self._name = name
if not isinstance(parent, BodyBase):
raise TypeError('Parent must be a body.')
self._parent = parent
if not isinstance(child, BodyBase):
raise TypeError('Child must be a body.')
self._child = child
if parent_axis is not None or child_axis is not None:
sympy_deprecation_warning(
"""
The parent_axis and child_axis arguments for the Joint classes
are deprecated. Instead use parent_interframe, child_interframe.
""",
deprecated_since_version="1.12",
active_deprecations_target="deprecated-mechanics-joint-axis",
stacklevel=4
)
if parent_interframe is None:
parent_interframe = parent_axis
if child_interframe is None:
child_interframe = child_axis
# Set parent and child frame attributes
if hasattr(self._parent, 'frame'):
self._parent_frame = self._parent.frame
else:
if isinstance(parent_interframe, ReferenceFrame):
self._parent_frame = parent_interframe
else:
self._parent_frame = ReferenceFrame(
f'{self.name}_{self._parent.name}_frame')
if hasattr(self._child, 'frame'):
self._child_frame = self._child.frame
else:
if isinstance(child_interframe, ReferenceFrame):
self._child_frame = child_interframe
else:
self._child_frame = ReferenceFrame(
f'{self.name}_{self._child.name}_frame')
self._parent_interframe = self._locate_joint_frame(
self._parent, parent_interframe, self._parent_frame)
self._child_interframe = self._locate_joint_frame(
self._child, child_interframe, self._child_frame)
self._parent_axis = self._axis(parent_axis, self._parent_frame)
self._child_axis = self._axis(child_axis, self._child_frame)
if parent_joint_pos is not None or child_joint_pos is not None:
sympy_deprecation_warning(
"""
The parent_joint_pos and child_joint_pos arguments for the Joint
classes are deprecated. Instead use parent_point and child_point.
""",
deprecated_since_version="1.12",
active_deprecations_target="deprecated-mechanics-joint-pos",
stacklevel=4
)
if parent_point is None:
parent_point = parent_joint_pos
if child_point is None:
child_point = child_joint_pos
self._parent_point = self._locate_joint_pos(
self._parent, parent_point, self._parent_frame)
self._child_point = self._locate_joint_pos(
self._child, child_point, self._child_frame)
self._coordinates = self._generate_coordinates(coordinates)
self._speeds = self._generate_speeds(speeds)
_validate_coordinates(self.coordinates, self.speeds)
self._kdes = self._generate_kdes()
self._orient_frames()
self._set_angular_velocity()
self._set_linear_velocity()
def __str__(self):
return self.name
def __repr__(self):
return self.__str__()
@property
def name(self):
"""Name of the joint."""
return self._name
@property
def parent(self):
"""Parent body of Joint."""
return self._parent
@property
def child(self):
"""Child body of Joint."""
return self._child
@property
def coordinates(self):
"""Matrix of the joint's generalized coordinates."""
return self._coordinates
@property
def speeds(self):
"""Matrix of the joint's generalized speeds."""
return self._speeds
@property
def kdes(self):
"""Kinematical differential equations of the joint."""
return self._kdes
@property
def parent_axis(self):
"""The axis of parent frame."""
# Will be removed with `deprecated-mechanics-joint-axis`
return self._parent_axis
@property
def child_axis(self):
"""The axis of child frame."""
# Will be removed with `deprecated-mechanics-joint-axis`
return self._child_axis
@property
def parent_point(self):
"""Attachment point where the joint is fixed to the parent body."""
return self._parent_point
@property
def child_point(self):
"""Attachment point where the joint is fixed to the child body."""
return self._child_point
@property
def parent_interframe(self):
return self._parent_interframe
@property
def child_interframe(self):
return self._child_interframe
@abstractmethod
def _generate_coordinates(self, coordinates):
"""Generate Matrix of the joint's generalized coordinates."""
pass
@abstractmethod
def _generate_speeds(self, speeds):
"""Generate Matrix of the joint's generalized speeds."""
pass
@abstractmethod
def _orient_frames(self):
"""Orient frames as per the joint."""
pass
@abstractmethod
def _set_angular_velocity(self):
"""Set angular velocity of the joint related frames."""
pass
@abstractmethod
def _set_linear_velocity(self):
"""Set velocity of related points to the joint."""
pass
@staticmethod
def _to_vector(matrix, frame):
"""Converts a matrix to a vector in the given frame."""
return Vector([(matrix, frame)])
@staticmethod
def _axis(ax, *frames):
"""Check whether an axis is fixed in one of the frames."""
if ax is None:
ax = frames[0].x
return ax
if not isinstance(ax, Vector):
raise TypeError("Axis must be a Vector.")
ref_frame = None # Find a body in which the axis can be expressed
for frame in frames:
try:
ax.to_matrix(frame)
except ValueError:
pass
else:
ref_frame = frame
break
if ref_frame is None:
raise ValueError("Axis cannot be expressed in one of the body's "
"frames.")
if not ax.dt(ref_frame) == 0:
raise ValueError('Axis cannot be time-varying when viewed from the '
'associated body.')
return ax
@staticmethod
def _choose_rotation_axis(frame, axis):
components = axis.to_matrix(frame)
x, y, z = components[0], components[1], components[2]
if x != 0:
if y != 0:
if z != 0:
return cross(axis, frame.x)
if z != 0:
return frame.y
return frame.z
else:
if y != 0:
return frame.x
return frame.y
@staticmethod
def _create_aligned_interframe(frame, align_axis, frame_axis=None,
frame_name=None):
"""
Returns an intermediate frame, where the ``frame_axis`` defined in
``frame`` is aligned with ``axis``. By default this means that the X
axis will be aligned with ``axis``.
Parameters
==========
frame : BodyBase or ReferenceFrame
The body or reference frame with respect to which the intermediate
frame is oriented.
align_axis : Vector
The vector with respect to which the intermediate frame will be
aligned.
frame_axis : Vector
The vector of the frame which should get aligned with ``axis``. The
default is the X axis of the frame.
frame_name : string
Name of the to be created intermediate frame. The default adds
"_int_frame" to the name of ``frame``.
Example
=======
An intermediate frame, where the X axis of the parent becomes aligned
with ``parent.y + parent.z`` can be created as follows:
>>> from sympy.physics.mechanics.joint import Joint
>>> from sympy.physics.mechanics import RigidBody
>>> parent = RigidBody('parent')
>>> parent_interframe = Joint._create_aligned_interframe(
... parent, parent.y + parent.z)
>>> parent_interframe
parent_int_frame
>>> parent.frame.dcm(parent_interframe)
Matrix([
[ 0, -sqrt(2)/2, -sqrt(2)/2],
[sqrt(2)/2, 1/2, -1/2],
[sqrt(2)/2, -1/2, 1/2]])
>>> (parent.y + parent.z).express(parent_interframe)
sqrt(2)*parent_int_frame.x
Notes
=====
The direction cosine matrix between the given frame and intermediate
frame is formed using a simple rotation about an axis that is normal to
both ``align_axis`` and ``frame_axis``. In general, the normal axis is
formed by crossing the ``frame_axis`` with the ``align_axis``. The
exception is if the axes are parallel with opposite directions, in which
case the rotation vector is chosen using the rules in the following
table with the vectors expressed in the given frame:
.. list-table::
:header-rows: 1
* - ``align_axis``
- ``frame_axis``
- ``rotation_axis``
* - ``-x``
- ``x``
- ``z``
* - ``-y``
- ``y``
- ``x``
* - ``-z``
- ``z``
- ``y``
* - ``-x-y``
- ``x+y``
- ``z``
* - ``-y-z``
- ``y+z``
- ``x``
* - ``-x-z``
- ``x+z``
- ``y``
* - ``-x-y-z``
- ``x+y+z``
- ``(x+y+z) × x``
"""
if isinstance(frame, BodyBase):
frame = frame.frame
if frame_axis is None:
frame_axis = frame.x
if frame_name is None:
if frame.name[-6:] == '_frame':
frame_name = f'{frame.name[:-6]}_int_frame'
else:
frame_name = f'{frame.name}_int_frame'
angle = frame_axis.angle_between(align_axis)
rotation_axis = cross(frame_axis, align_axis)
if rotation_axis == Vector(0) and angle == 0:
return frame
if angle == pi:
rotation_axis = Joint._choose_rotation_axis(frame, align_axis)
int_frame = ReferenceFrame(frame_name)
int_frame.orient_axis(frame, rotation_axis, angle)
int_frame.set_ang_vel(frame, 0 * rotation_axis)
return int_frame
def _generate_kdes(self):
"""Generate kinematical differential equations."""
kdes = []
t = dynamicsymbols._t
for i in range(len(self.coordinates)):
kdes.append(-self.coordinates[i].diff(t) + self.speeds[i])
return Matrix(kdes)
def _locate_joint_pos(self, body, joint_pos, body_frame=None):
"""Returns the attachment point of a body."""
if body_frame is None:
body_frame = body.frame
if joint_pos is None:
return body.masscenter
if not isinstance(joint_pos, (Point, Vector)):
raise TypeError('Attachment point must be a Point or Vector.')
if isinstance(joint_pos, Vector):
point_name = f'{self.name}_{body.name}_joint'
joint_pos = body.masscenter.locatenew(point_name, joint_pos)
if not joint_pos.pos_from(body.masscenter).dt(body_frame) == 0:
raise ValueError('Attachment point must be fixed to the associated '
'body.')
return joint_pos
def _locate_joint_frame(self, body, interframe, body_frame=None):
"""Returns the attachment frame of a body."""
if body_frame is None:
body_frame = body.frame
if interframe is None:
return body_frame
if isinstance(interframe, Vector):
interframe = Joint._create_aligned_interframe(
body_frame, interframe,
frame_name=f'{self.name}_{body.name}_int_frame')
elif not isinstance(interframe, ReferenceFrame):
raise TypeError('Interframe must be a ReferenceFrame.')
if not interframe.ang_vel_in(body_frame) == 0:
raise ValueError(f'Interframe {interframe} is not fixed to body '
f'{body}.')
body.masscenter.set_vel(interframe, 0) # Fixate interframe to body
return interframe
def _fill_coordinate_list(self, coordinates, n_coords, label='q', offset=0,
number_single=False):
"""Helper method for _generate_coordinates and _generate_speeds.
Parameters
==========
coordinates : iterable
Iterable of coordinates or speeds that have been provided.
n_coords : Integer
Number of coordinates that should be returned.
label : String, optional
Coordinate type either 'q' (coordinates) or 'u' (speeds). The
Default is 'q'.
offset : Integer
Count offset when creating new dynamicsymbols. The default is 0.
number_single : Boolean
Boolean whether if n_coords == 1, number should still be used. The
default is False.
"""
def create_symbol(number):
if n_coords == 1 and not number_single:
return dynamicsymbols(f'{label}_{self.name}')
return dynamicsymbols(f'{label}{number}_{self.name}')
name = 'generalized coordinate' if label == 'q' else 'generalized speed'
generated_coordinates = []
if coordinates is None:
coordinates = []
elif not iterable(coordinates):
coordinates = [coordinates]
if not (len(coordinates) == 0 or len(coordinates) == n_coords):
raise ValueError(f'Expected {n_coords} {name}s, instead got '
f'{len(coordinates)} {name}s.')
# Supports more iterables, also Matrix
for i, coord in enumerate(coordinates):
if coord is None:
generated_coordinates.append(create_symbol(i + offset))
elif isinstance(coord, (AppliedUndef, Derivative)):
generated_coordinates.append(coord)
else:
raise TypeError(f'The {name} {coord} should have been a '
f'dynamicsymbol.')
for i in range(len(coordinates) + offset, n_coords + offset):
generated_coordinates.append(create_symbol(i))
return Matrix(generated_coordinates)
class PinJoint(Joint):
"""Pin (Revolute) Joint.
.. raw:: html
:file: ../../../doc/src/modules/physics/mechanics/api/PinJoint.svg
Explanation
===========
A pin joint is defined such that the joint rotation axis is fixed in both
the child and parent and the location of the joint is relative to the mass
center of each body. The child rotates an angle, θ, from the parent about
the rotation axis and has a simple angular speed, ω, relative to the
parent. The direction cosine matrix between the child interframe and
parent interframe is formed using a simple rotation about the joint axis.
The page on the joints framework gives a more detailed explanation of the
intermediate frames.
Parameters
==========
name : string
A unique name for the joint.
parent : Particle or RigidBody or Body
The parent body of joint.
child : Particle or RigidBody or Body
The child body of joint.
coordinates : dynamicsymbol, optional
Generalized coordinates of the joint.
speeds : dynamicsymbol, optional
Generalized speeds of joint.
parent_point : Point or Vector, optional
Attachment point where the joint is fixed to the parent body. If a
vector is provided, then the attachment point is computed by adding the
vector to the body's mass center. The default value is the parent's mass
center.
child_point : Point or Vector, optional
Attachment point where the joint is fixed to the child body. If a
vector is provided, then the attachment point is computed by adding the
vector to the body's mass center. The default value is the child's mass
center.
parent_axis : Vector, optional
.. deprecated:: 1.12
Axis fixed in the parent body which aligns with an axis fixed in the
child body. The default is the x axis of parent's reference frame.
For more information on this deprecation, see
:ref:`deprecated-mechanics-joint-axis`.
child_axis : Vector, optional
.. deprecated:: 1.12
Axis fixed in the child body which aligns with an axis fixed in the
parent body. The default is the x axis of child's reference frame.
For more information on this deprecation, see
:ref:`deprecated-mechanics-joint-axis`.
parent_interframe : ReferenceFrame, optional
Intermediate frame of the parent body with respect to which the joint
transformation is formulated. If a Vector is provided then an interframe
is created which aligns its X axis with the given vector. The default
value is the parent's own frame.
child_interframe : ReferenceFrame, optional
Intermediate frame of the child body with respect to which the joint
transformation is formulated. If a Vector is provided then an interframe
is created which aligns its X axis with the given vector. The default
value is the child's own frame.
joint_axis : Vector
The axis about which the rotation occurs. Note that the components
of this axis are the same in the parent_interframe and child_interframe.
parent_joint_pos : Point or Vector, optional
.. deprecated:: 1.12
This argument is replaced by parent_point and will be removed in a
future version.
See :ref:`deprecated-mechanics-joint-pos` for more information.
child_joint_pos : Point or Vector, optional
.. deprecated:: 1.12
This argument is replaced by child_point and will be removed in a
future version.
See :ref:`deprecated-mechanics-joint-pos` for more information.
Attributes
==========
name : string
The joint's name.
parent : Particle or RigidBody or Body
The joint's parent body.
child : Particle or RigidBody or Body
The joint's child body.
coordinates : Matrix
Matrix of the joint's generalized coordinates. The default value is
``dynamicsymbols(f'q_{joint.name}')``.
speeds : Matrix
Matrix of the joint's generalized speeds. The default value is
``dynamicsymbols(f'u_{joint.name}')``.
parent_point : Point
Attachment point where the joint is fixed to the parent body.
child_point : Point
Attachment point where the joint is fixed to the child body.
parent_axis : Vector
The axis fixed in the parent frame that represents the joint.
child_axis : Vector
The axis fixed in the child frame that represents the joint.
parent_interframe : ReferenceFrame
Intermediate frame of the parent body with respect to which the joint
transformation is formulated.
child_interframe : ReferenceFrame
Intermediate frame of the child body with respect to which the joint
transformation is formulated.
joint_axis : Vector
The axis about which the rotation occurs. Note that the components of
this axis are the same in the parent_interframe and child_interframe.
kdes : Matrix
Kinematical differential equations of the joint.
Examples
=========
A single pin joint is created from two bodies and has the following basic
attributes:
>>> from sympy.physics.mechanics import RigidBody, PinJoint
>>> parent = RigidBody('P')
>>> parent
P
>>> child = RigidBody('C')
>>> child
C
>>> joint = PinJoint('PC', parent, child)
>>> joint
PinJoint: PC parent: P child: C
>>> joint.name
'PC'
>>> joint.parent
P
>>> joint.child
C
>>> joint.parent_point
P_masscenter
>>> joint.child_point
C_masscenter
>>> joint.parent_axis
P_frame.x
>>> joint.child_axis
C_frame.x
>>> joint.coordinates
Matrix([[q_PC(t)]])
>>> joint.speeds
Matrix([[u_PC(t)]])
>>> child.frame.ang_vel_in(parent.frame)
u_PC(t)*P_frame.x
>>> child.frame.dcm(parent.frame)
Matrix([
[1, 0, 0],
[0, cos(q_PC(t)), sin(q_PC(t))],
[0, -sin(q_PC(t)), cos(q_PC(t))]])
>>> joint.child_point.pos_from(joint.parent_point)
0
To further demonstrate the use of the pin joint, the kinematics of simple
double pendulum that rotates about the Z axis of each connected body can be
created as follows.
>>> from sympy import symbols, trigsimp
>>> from sympy.physics.mechanics import RigidBody, PinJoint
>>> l1, l2 = symbols('l1 l2')
First create bodies to represent the fixed ceiling and one to represent
each pendulum bob.
>>> ceiling = RigidBody('C')
>>> upper_bob = RigidBody('U')
>>> lower_bob = RigidBody('L')
The first joint will connect the upper bob to the ceiling by a distance of
``l1`` and the joint axis will be about the Z axis for each body.
>>> ceiling_joint = PinJoint('P1', ceiling, upper_bob,
... child_point=-l1*upper_bob.frame.x,
... joint_axis=ceiling.frame.z)
The second joint will connect the lower bob to the upper bob by a distance
of ``l2`` and the joint axis will also be about the Z axis for each body.
>>> pendulum_joint = PinJoint('P2', upper_bob, lower_bob,
... child_point=-l2*lower_bob.frame.x,
... joint_axis=upper_bob.frame.z)
Once the joints are established the kinematics of the connected bodies can
be accessed. First the direction cosine matrices of pendulum link relative
to the ceiling are found:
>>> upper_bob.frame.dcm(ceiling.frame)
Matrix([
[ cos(q_P1(t)), sin(q_P1(t)), 0],
[-sin(q_P1(t)), cos(q_P1(t)), 0],
[ 0, 0, 1]])
>>> trigsimp(lower_bob.frame.dcm(ceiling.frame))
Matrix([
[ cos(q_P1(t) + q_P2(t)), sin(q_P1(t) + q_P2(t)), 0],
[-sin(q_P1(t) + q_P2(t)), cos(q_P1(t) + q_P2(t)), 0],
[ 0, 0, 1]])
The position of the lower bob's masscenter is found with:
>>> lower_bob.masscenter.pos_from(ceiling.masscenter)
l1*U_frame.x + l2*L_frame.x
The angular velocities of the two pendulum links can be computed with
respect to the ceiling.
>>> upper_bob.frame.ang_vel_in(ceiling.frame)
u_P1(t)*C_frame.z
>>> lower_bob.frame.ang_vel_in(ceiling.frame)
u_P1(t)*C_frame.z + u_P2(t)*U_frame.z
And finally, the linear velocities of the two pendulum bobs can be computed
with respect to the ceiling.
>>> upper_bob.masscenter.vel(ceiling.frame)
l1*u_P1(t)*U_frame.y
>>> lower_bob.masscenter.vel(ceiling.frame)
l1*u_P1(t)*U_frame.y + l2*(u_P1(t) + u_P2(t))*L_frame.y
"""
def __init__(self, name, parent, child, coordinates=None, speeds=None,
parent_point=None, child_point=None, parent_interframe=None,
child_interframe=None, parent_axis=None, child_axis=None,
joint_axis=None, parent_joint_pos=None, child_joint_pos=None):
self._joint_axis = joint_axis
super().__init__(name, parent, child, coordinates, speeds, parent_point,
child_point, parent_interframe, child_interframe,
parent_axis, child_axis, parent_joint_pos,
child_joint_pos)
def __str__(self):
return (f'PinJoint: {self.name} parent: {self.parent} '
f'child: {self.child}')
@property
def joint_axis(self):
"""Axis about which the child rotates with respect to the parent."""
return self._joint_axis
def _generate_coordinates(self, coordinate):
return self._fill_coordinate_list(coordinate, 1, 'q')
def _generate_speeds(self, speed):
return self._fill_coordinate_list(speed, 1, 'u')
def _orient_frames(self):
self._joint_axis = self._axis(self.joint_axis, self.parent_interframe)
self.child_interframe.orient_axis(
self.parent_interframe, self.joint_axis, self.coordinates[0])
def _set_angular_velocity(self):
self.child_interframe.set_ang_vel(self.parent_interframe, self.speeds[
0] * self.joint_axis.normalize())
def _set_linear_velocity(self):
self.child_point.set_pos(self.parent_point, 0)
self.parent_point.set_vel(self._parent_frame, 0)
self.child_point.set_vel(self._child_frame, 0)
self.child.masscenter.v2pt_theory(self.parent_point,
self._parent_frame, self._child_frame)
class PrismaticJoint(Joint):
"""Prismatic (Sliding) Joint.
.. image:: PrismaticJoint.svg
Explanation
===========
It is defined such that the child body translates with respect to the parent
body along the body-fixed joint axis. The location of the joint is defined
by two points, one in each body, which coincide when the generalized
coordinate is zero. The direction cosine matrix between the
parent_interframe and child_interframe is the identity matrix. Therefore,
the direction cosine matrix between the parent and child frames is fully
defined by the definition of the intermediate frames. The page on the joints
framework gives a more detailed explanation of the intermediate frames.
Parameters
==========
name : string
A unique name for the joint.
parent : Particle or RigidBody or Body
The parent body of joint.
child : Particle or RigidBody or Body
The child body of joint.
coordinates : dynamicsymbol, optional
Generalized coordinates of the joint. The default value is
``dynamicsymbols(f'q_{joint.name}')``.
speeds : dynamicsymbol, optional
Generalized speeds of joint. The default value is
``dynamicsymbols(f'u_{joint.name}')``.
parent_point : Point or Vector, optional
Attachment point where the joint is fixed to the parent body. If a
vector is provided, then the attachment point is computed by adding the
vector to the body's mass center. The default value is the parent's mass
center.
child_point : Point or Vector, optional
Attachment point where the joint is fixed to the child body. If a
vector is provided, then the attachment point is computed by adding the
vector to the body's mass center. The default value is the child's mass
center.
parent_axis : Vector, optional
.. deprecated:: 1.12
Axis fixed in the parent body which aligns with an axis fixed in the
child body. The default is the x axis of parent's reference frame.
For more information on this deprecation, see
:ref:`deprecated-mechanics-joint-axis`.
child_axis : Vector, optional
.. deprecated:: 1.12
Axis fixed in the child body which aligns with an axis fixed in the
parent body. The default is the x axis of child's reference frame.
For more information on this deprecation, see
:ref:`deprecated-mechanics-joint-axis`.
parent_interframe : ReferenceFrame, optional
Intermediate frame of the parent body with respect to which the joint
transformation is formulated. If a Vector is provided then an interframe
is created which aligns its X axis with the given vector. The default
value is the parent's own frame.
child_interframe : ReferenceFrame, optional
Intermediate frame of the child body with respect to which the joint
transformation is formulated. If a Vector is provided then an interframe
is created which aligns its X axis with the given vector. The default
value is the child's own frame.
joint_axis : Vector
The axis along which the translation occurs. Note that the components
of this axis are the same in the parent_interframe and child_interframe.
parent_joint_pos : Point or Vector, optional
.. deprecated:: 1.12
This argument is replaced by parent_point and will be removed in a
future version.
See :ref:`deprecated-mechanics-joint-pos` for more information.
child_joint_pos : Point or Vector, optional
.. deprecated:: 1.12
This argument is replaced by child_point and will be removed in a
future version.
See :ref:`deprecated-mechanics-joint-pos` for more information.
Attributes
==========
name : string
The joint's name.
parent : Particle or RigidBody or Body
The joint's parent body.
child : Particle or RigidBody or Body
The joint's child body.
coordinates : Matrix
Matrix of the joint's generalized coordinates.
speeds : Matrix
Matrix of the joint's generalized speeds.
parent_point : Point
Attachment point where the joint is fixed to the parent body.
child_point : Point
Attachment point where the joint is fixed to the child body.
parent_axis : Vector
The axis fixed in the parent frame that represents the joint.
child_axis : Vector
The axis fixed in the child frame that represents the joint.
parent_interframe : ReferenceFrame
Intermediate frame of the parent body with respect to which the joint
transformation is formulated.
child_interframe : ReferenceFrame
Intermediate frame of the child body with respect to which the joint
transformation is formulated.
kdes : Matrix
Kinematical differential equations of the joint.
Examples
=========
A single prismatic joint is created from two bodies and has the following
basic attributes:
>>> from sympy.physics.mechanics import RigidBody, PrismaticJoint
>>> parent = RigidBody('P')
>>> parent
P
>>> child = RigidBody('C')
>>> child
C
>>> joint = PrismaticJoint('PC', parent, child)
>>> joint
PrismaticJoint: PC parent: P child: C
>>> joint.name
'PC'
>>> joint.parent
P
>>> joint.child
C
>>> joint.parent_point
P_masscenter
>>> joint.child_point
C_masscenter
>>> joint.parent_axis
P_frame.x
>>> joint.child_axis
C_frame.x
>>> joint.coordinates
Matrix([[q_PC(t)]])
>>> joint.speeds
Matrix([[u_PC(t)]])
>>> child.frame.ang_vel_in(parent.frame)
0
>>> child.frame.dcm(parent.frame)
Matrix([
[1, 0, 0],
[0, 1, 0],
[0, 0, 1]])
>>> joint.child_point.pos_from(joint.parent_point)
q_PC(t)*P_frame.x
To further demonstrate the use of the prismatic joint, the kinematics of two
masses sliding, one moving relative to a fixed body and the other relative
to the moving body. about the X axis of each connected body can be created
as follows.
>>> from sympy.physics.mechanics import PrismaticJoint, RigidBody
First create bodies to represent the fixed ceiling and one to represent
a particle.
>>> wall = RigidBody('W')
>>> Part1 = RigidBody('P1')
>>> Part2 = RigidBody('P2')
The first joint will connect the particle to the ceiling and the
joint axis will be about the X axis for each body.
>>> J1 = PrismaticJoint('J1', wall, Part1)
The second joint will connect the second particle to the first particle
and the joint axis will also be about the X axis for each body.
>>> J2 = PrismaticJoint('J2', Part1, Part2)
Once the joint is established the kinematics of the connected bodies can
be accessed. First the direction cosine matrices of Part relative
to the ceiling are found:
>>> Part1.frame.dcm(wall.frame)
Matrix([
[1, 0, 0],
[0, 1, 0],
[0, 0, 1]])
>>> Part2.frame.dcm(wall.frame)
Matrix([
[1, 0, 0],
[0, 1, 0],
[0, 0, 1]])
The position of the particles' masscenter is found with:
>>> Part1.masscenter.pos_from(wall.masscenter)
q_J1(t)*W_frame.x
>>> Part2.masscenter.pos_from(wall.masscenter)
q_J1(t)*W_frame.x + q_J2(t)*P1_frame.x
The angular velocities of the two particle links can be computed with
respect to the ceiling.
>>> Part1.frame.ang_vel_in(wall.frame)
0
>>> Part2.frame.ang_vel_in(wall.frame)
0
And finally, the linear velocities of the two particles can be computed
with respect to the ceiling.
>>> Part1.masscenter.vel(wall.frame)
u_J1(t)*W_frame.x
>>> Part2.masscenter.vel(wall.frame)
u_J1(t)*W_frame.x + Derivative(q_J2(t), t)*P1_frame.x
"""
def __init__(self, name, parent, child, coordinates=None, speeds=None,
parent_point=None, child_point=None, parent_interframe=None,
child_interframe=None, parent_axis=None, child_axis=None,
joint_axis=None, parent_joint_pos=None, child_joint_pos=None):
self._joint_axis = joint_axis
super().__init__(name, parent, child, coordinates, speeds, parent_point,
child_point, parent_interframe, child_interframe,
parent_axis, child_axis, parent_joint_pos,
child_joint_pos)
def __str__(self):
return (f'PrismaticJoint: {self.name} parent: {self.parent} '
f'child: {self.child}')
@property
def joint_axis(self):
"""Axis along which the child translates with respect to the parent."""
return self._joint_axis
def _generate_coordinates(self, coordinate):
return self._fill_coordinate_list(coordinate, 1, 'q')
def _generate_speeds(self, speed):
return self._fill_coordinate_list(speed, 1, 'u')
def _orient_frames(self):
self._joint_axis = self._axis(self.joint_axis, self.parent_interframe)
self.child_interframe.orient_axis(
self.parent_interframe, self.joint_axis, 0)
def _set_angular_velocity(self):
self.child_interframe.set_ang_vel(self.parent_interframe, 0)
def _set_linear_velocity(self):
axis = self.joint_axis.normalize()
self.child_point.set_pos(self.parent_point, self.coordinates[0] * axis)
self.parent_point.set_vel(self._parent_frame, 0)
self.child_point.set_vel(self._child_frame, 0)
self.child_point.set_vel(self._parent_frame, self.speeds[0] * axis)
self.child.masscenter.set_vel(self._parent_frame, self.speeds[0] * axis)
class CylindricalJoint(Joint):
"""Cylindrical Joint.
.. image:: CylindricalJoint.svg
:align: center
:width: 600
Explanation
===========
A cylindrical joint is defined such that the child body both rotates about
and translates along the body-fixed joint axis with respect to the parent
body. The joint axis is both the rotation axis and translation axis. The
location of the joint is defined by two points, one in each body, which
coincide when the generalized coordinate corresponding to the translation is
zero. The direction cosine matrix between the child interframe and parent
interframe is formed using a simple rotation about the joint axis. The page
on the joints framework gives a more detailed explanation of the
intermediate frames.
Parameters
==========
name : string
A unique name for the joint.
parent : Particle or RigidBody or Body
The parent body of joint.
child : Particle or RigidBody or Body
The child body of joint.
rotation_coordinate : dynamicsymbol, optional
Generalized coordinate corresponding to the rotation angle. The default
value is ``dynamicsymbols(f'q0_{joint.name}')``.
translation_coordinate : dynamicsymbol, optional
Generalized coordinate corresponding to the translation distance. The
default value is ``dynamicsymbols(f'q1_{joint.name}')``.
rotation_speed : dynamicsymbol, optional
Generalized speed corresponding to the angular velocity. The default
value is ``dynamicsymbols(f'u0_{joint.name}')``.
translation_speed : dynamicsymbol, optional
Generalized speed corresponding to the translation velocity. The default
value is ``dynamicsymbols(f'u1_{joint.name}')``.
parent_point : Point or Vector, optional
Attachment point where the joint is fixed to the parent body. If a
vector is provided, then the attachment point is computed by adding the
vector to the body's mass center. The default value is the parent's mass
center.
child_point : Point or Vector, optional
Attachment point where the joint is fixed to the child body. If a
vector is provided, then the attachment point is computed by adding the
vector to the body's mass center. The default value is the child's mass
center.
parent_interframe : ReferenceFrame, optional
Intermediate frame of the parent body with respect to which the joint
transformation is formulated. If a Vector is provided then an interframe
is created which aligns its X axis with the given vector. The default
value is the parent's own frame.
child_interframe : ReferenceFrame, optional
Intermediate frame of the child body with respect to which the joint
transformation is formulated. If a Vector is provided then an interframe
is created which aligns its X axis with the given vector. The default
value is the child's own frame.
joint_axis : Vector, optional
The rotation as well as translation axis. Note that the components of
this axis are the same in the parent_interframe and child_interframe.
Attributes
==========
name : string
The joint's name.
parent : Particle or RigidBody or Body
The joint's parent body.
child : Particle or RigidBody or Body
The joint's child body.
rotation_coordinate : dynamicsymbol
Generalized coordinate corresponding to the rotation angle.
translation_coordinate : dynamicsymbol
Generalized coordinate corresponding to the translation distance.
rotation_speed : dynamicsymbol
Generalized speed corresponding to the angular velocity.
translation_speed : dynamicsymbol
Generalized speed corresponding to the translation velocity.
coordinates : Matrix
Matrix of the joint's generalized coordinates.
speeds : Matrix
Matrix of the joint's generalized speeds.
parent_point : Point
Attachment point where the joint is fixed to the parent body.
child_point : Point
Attachment point where the joint is fixed to the child body.
parent_interframe : ReferenceFrame
Intermediate frame of the parent body with respect to which the joint
transformation is formulated.
child_interframe : ReferenceFrame
Intermediate frame of the child body with respect to which the joint
transformation is formulated.
kdes : Matrix
Kinematical differential equations of the joint.
joint_axis : Vector
The axis of rotation and translation.
Examples
=========
A single cylindrical joint is created between two bodies and has the
following basic attributes:
>>> from sympy.physics.mechanics import RigidBody, CylindricalJoint
>>> parent = RigidBody('P')
>>> parent
P
>>> child = RigidBody('C')
>>> child
C
>>> joint = CylindricalJoint('PC', parent, child)
>>> joint
CylindricalJoint: PC parent: P child: C
>>> joint.name
'PC'
>>> joint.parent
P
>>> joint.child
C
>>> joint.parent_point
P_masscenter
>>> joint.child_point
C_masscenter
>>> joint.parent_axis
P_frame.x
>>> joint.child_axis
C_frame.x
>>> joint.coordinates
Matrix([
[q0_PC(t)],
[q1_PC(t)]])
>>> joint.speeds
Matrix([
[u0_PC(t)],
[u1_PC(t)]])
>>> child.frame.ang_vel_in(parent.frame)
u0_PC(t)*P_frame.x
>>> child.frame.dcm(parent.frame)
Matrix([
[1, 0, 0],
[0, cos(q0_PC(t)), sin(q0_PC(t))],
[0, -sin(q0_PC(t)), cos(q0_PC(t))]])
>>> joint.child_point.pos_from(joint.parent_point)
q1_PC(t)*P_frame.x
>>> child.masscenter.vel(parent.frame)
u1_PC(t)*P_frame.x
To further demonstrate the use of the cylindrical joint, the kinematics of
two cylindrical joints perpendicular to each other can be created as follows.
>>> from sympy import symbols
>>> from sympy.physics.mechanics import RigidBody, CylindricalJoint
>>> r, l, w = symbols('r l w')
First create bodies to represent the fixed floor with a fixed pole on it.
The second body represents a freely moving tube around that pole. The third
body represents a solid flag freely translating along and rotating around
the Y axis of the tube.
>>> floor = RigidBody('floor')
>>> tube = RigidBody('tube')
>>> flag = RigidBody('flag')
The first joint will connect the first tube to the floor with it translating
along and rotating around the Z axis of both bodies.
>>> floor_joint = CylindricalJoint('C1', floor, tube, joint_axis=floor.z)
The second joint will connect the tube perpendicular to the flag along the Y
axis of both the tube and the flag, with the joint located at a distance
``r`` from the tube's center of mass and a combination of the distances
``l`` and ``w`` from the flag's center of mass.
>>> flag_joint = CylindricalJoint('C2', tube, flag,
... parent_point=r * tube.y,
... child_point=-w * flag.y + l * flag.z,
... joint_axis=tube.y)
Once the joints are established the kinematics of the connected bodies can
be accessed. First the direction cosine matrices of both the body and the
flag relative to the floor are found:
>>> tube.frame.dcm(floor.frame)
Matrix([
[ cos(q0_C1(t)), sin(q0_C1(t)), 0],
[-sin(q0_C1(t)), cos(q0_C1(t)), 0],
[ 0, 0, 1]])
>>> flag.frame.dcm(floor.frame)
Matrix([
[cos(q0_C1(t))*cos(q0_C2(t)), sin(q0_C1(t))*cos(q0_C2(t)), -sin(q0_C2(t))],
[ -sin(q0_C1(t)), cos(q0_C1(t)), 0],
[sin(q0_C2(t))*cos(q0_C1(t)), sin(q0_C1(t))*sin(q0_C2(t)), cos(q0_C2(t))]])
The position of the flag's center of mass is found with:
>>> flag.masscenter.pos_from(floor.masscenter)
q1_C1(t)*floor_frame.z + (r + q1_C2(t))*tube_frame.y + w*flag_frame.y - l*flag_frame.z
The angular velocities of the two tubes can be computed with respect to the
floor.
>>> tube.frame.ang_vel_in(floor.frame)
u0_C1(t)*floor_frame.z
>>> flag.frame.ang_vel_in(floor.frame)
u0_C1(t)*floor_frame.z + u0_C2(t)*tube_frame.y
Finally, the linear velocities of the two tube centers of mass can be
computed with respect to the floor, while expressed in the tube's frame.
>>> tube.masscenter.vel(floor.frame).to_matrix(tube.frame)
Matrix([
[ 0],
[ 0],
[u1_C1(t)]])
>>> flag.masscenter.vel(floor.frame).to_matrix(tube.frame).simplify()
Matrix([
[-l*u0_C2(t)*cos(q0_C2(t)) - r*u0_C1(t) - w*u0_C1(t) - q1_C2(t)*u0_C1(t)],
[ -l*u0_C1(t)*sin(q0_C2(t)) + Derivative(q1_C2(t), t)],
[ l*u0_C2(t)*sin(q0_C2(t)) + u1_C1(t)]])
"""
def __init__(self, name, parent, child, rotation_coordinate=None,
translation_coordinate=None, rotation_speed=None,
translation_speed=None, parent_point=None, child_point=None,
parent_interframe=None, child_interframe=None,
joint_axis=None):
self._joint_axis = joint_axis
coordinates = (rotation_coordinate, translation_coordinate)
speeds = (rotation_speed, translation_speed)
super().__init__(name, parent, child, coordinates, speeds,
parent_point, child_point,
parent_interframe=parent_interframe,
child_interframe=child_interframe)
def __str__(self):
return (f'CylindricalJoint: {self.name} parent: {self.parent} '
f'child: {self.child}')
@property
def joint_axis(self):
"""Axis about and along which the rotation and translation occurs."""
return self._joint_axis
@property
def rotation_coordinate(self):
"""Generalized coordinate corresponding to the rotation angle."""
return self.coordinates[0]
@property
def translation_coordinate(self):
"""Generalized coordinate corresponding to the translation distance."""
return self.coordinates[1]
@property
def rotation_speed(self):
"""Generalized speed corresponding to the angular velocity."""
return self.speeds[0]
@property
def translation_speed(self):
"""Generalized speed corresponding to the translation velocity."""
return self.speeds[1]
def _generate_coordinates(self, coordinates):
return self._fill_coordinate_list(coordinates, 2, 'q')
def _generate_speeds(self, speeds):
return self._fill_coordinate_list(speeds, 2, 'u')
def _orient_frames(self):
self._joint_axis = self._axis(self.joint_axis, self.parent_interframe)
self.child_interframe.orient_axis(
self.parent_interframe, self.joint_axis, self.rotation_coordinate)
def _set_angular_velocity(self):
self.child_interframe.set_ang_vel(
self.parent_interframe,
self.rotation_speed * self.joint_axis.normalize())
def _set_linear_velocity(self):
self.child_point.set_pos(
self.parent_point,
self.translation_coordinate * self.joint_axis.normalize())
self.parent_point.set_vel(self._parent_frame, 0)
self.child_point.set_vel(self._child_frame, 0)
self.child_point.set_vel(
self._parent_frame,
self.translation_speed * self.joint_axis.normalize())
self.child.masscenter.v2pt_theory(self.child_point, self._parent_frame,
self.child_interframe)
class PlanarJoint(Joint):
"""Planar Joint.
.. raw:: html
:file: ../../../doc/src/modules/physics/mechanics/api/PlanarJoint.svg
Explanation
===========
A planar joint is defined such that the child body translates over a fixed
plane of the parent body as well as rotate about the rotation axis, which
is perpendicular to that plane. The origin of this plane is the
``parent_point`` and the plane is spanned by two nonparallel planar vectors.
The location of the ``child_point`` is based on the planar vectors
($\\vec{v}_1$, $\\vec{v}_2$) and generalized coordinates ($q_1$, $q_2$),
i.e. $\\vec{r} = q_1 \\hat{v}_1 + q_2 \\hat{v}_2$. The direction cosine
matrix between the ``child_interframe`` and ``parent_interframe`` is formed
using a simple rotation ($q_0$) about the rotation axis.
In order to simplify the definition of the ``PlanarJoint``, the
``rotation_axis`` and ``planar_vectors`` are set to be the unit vectors of
the ``parent_interframe`` according to the table below. This ensures that
you can only define these vectors by creating a separate frame and supplying
that as the interframe. If you however would only like to supply the normals
of the plane with respect to the parent and child bodies, then you can also
supply those to the ``parent_interframe`` and ``child_interframe``
arguments. An example of both of these cases is in the examples section
below and the page on the joints framework provides a more detailed
explanation of the intermediate frames.
.. list-table::
* - ``rotation_axis``
- ``parent_interframe.x``
* - ``planar_vectors[0]``
- ``parent_interframe.y``
* - ``planar_vectors[1]``
- ``parent_interframe.z``
Parameters
==========
name : string
A unique name for the joint.
parent : Particle or RigidBody or Body
The parent body of joint.
child : Particle or RigidBody or Body
The child body of joint.
rotation_coordinate : dynamicsymbol, optional
Generalized coordinate corresponding to the rotation angle. The default
value is ``dynamicsymbols(f'q0_{joint.name}')``.
planar_coordinates : iterable of dynamicsymbols, optional
Two generalized coordinates used for the planar translation. The default
value is ``dynamicsymbols(f'q1_{joint.name} q2_{joint.name}')``.
rotation_speed : dynamicsymbol, optional
Generalized speed corresponding to the angular velocity. The default
value is ``dynamicsymbols(f'u0_{joint.name}')``.
planar_speeds : dynamicsymbols, optional
Two generalized speeds used for the planar translation velocity. The
default value is ``dynamicsymbols(f'u1_{joint.name} u2_{joint.name}')``.
parent_point : Point or Vector, optional
Attachment point where the joint is fixed to the parent body. If a
vector is provided, then the attachment point is computed by adding the
vector to the body's mass center. The default value is the parent's mass
center.
child_point : Point or Vector, optional
Attachment point where the joint is fixed to the child body. If a
vector is provided, then the attachment point is computed by adding the
vector to the body's mass center. The default value is the child's mass
center.
parent_interframe : ReferenceFrame, optional
Intermediate frame of the parent body with respect to which the joint
transformation is formulated. If a Vector is provided then an interframe
is created which aligns its X axis with the given vector. The default
value is the parent's own frame.
child_interframe : ReferenceFrame, optional
Intermediate frame of the child body with respect to which the joint
transformation is formulated. If a Vector is provided then an interframe
is created which aligns its X axis with the given vector. The default
value is the child's own frame.
Attributes
==========
name : string
The joint's name.
parent : Particle or RigidBody or Body
The joint's parent body.
child : Particle or RigidBody or Body
The joint's child body.
rotation_coordinate : dynamicsymbol
Generalized coordinate corresponding to the rotation angle.
planar_coordinates : Matrix
Two generalized coordinates used for the planar translation.
rotation_speed : dynamicsymbol
Generalized speed corresponding to the angular velocity.
planar_speeds : Matrix
Two generalized speeds used for the planar translation velocity.
coordinates : Matrix
Matrix of the joint's generalized coordinates.
speeds : Matrix
Matrix of the joint's generalized speeds.
parent_point : Point
Attachment point where the joint is fixed to the parent body.
child_point : Point
Attachment point where the joint is fixed to the child body.
parent_interframe : ReferenceFrame
Intermediate frame of the parent body with respect to which the joint
transformation is formulated.
child_interframe : ReferenceFrame
Intermediate frame of the child body with respect to which the joint
transformation is formulated.
kdes : Matrix
Kinematical differential equations of the joint.
rotation_axis : Vector
The axis about which the rotation occurs.
planar_vectors : list
The vectors that describe the planar translation directions.
Examples
=========
A single planar joint is created between two bodies and has the following
basic attributes:
>>> from sympy.physics.mechanics import RigidBody, PlanarJoint
>>> parent = RigidBody('P')
>>> parent
P
>>> child = RigidBody('C')
>>> child
C
>>> joint = PlanarJoint('PC', parent, child)
>>> joint
PlanarJoint: PC parent: P child: C
>>> joint.name
'PC'
>>> joint.parent
P
>>> joint.child
C
>>> joint.parent_point
P_masscenter
>>> joint.child_point
C_masscenter
>>> joint.rotation_axis
P_frame.x
>>> joint.planar_vectors
[P_frame.y, P_frame.z]
>>> joint.rotation_coordinate
q0_PC(t)
>>> joint.planar_coordinates
Matrix([
[q1_PC(t)],
[q2_PC(t)]])
>>> joint.coordinates
Matrix([
[q0_PC(t)],
[q1_PC(t)],
[q2_PC(t)]])
>>> joint.rotation_speed
u0_PC(t)
>>> joint.planar_speeds
Matrix([
[u1_PC(t)],
[u2_PC(t)]])
>>> joint.speeds
Matrix([
[u0_PC(t)],
[u1_PC(t)],
[u2_PC(t)]])
>>> child.frame.ang_vel_in(parent.frame)
u0_PC(t)*P_frame.x
>>> child.frame.dcm(parent.frame)
Matrix([
[1, 0, 0],
[0, cos(q0_PC(t)), sin(q0_PC(t))],
[0, -sin(q0_PC(t)), cos(q0_PC(t))]])
>>> joint.child_point.pos_from(joint.parent_point)
q1_PC(t)*P_frame.y + q2_PC(t)*P_frame.z
>>> child.masscenter.vel(parent.frame)
u1_PC(t)*P_frame.y + u2_PC(t)*P_frame.z
To further demonstrate the use of the planar joint, the kinematics of a
block sliding on a slope, can be created as follows.
>>> from sympy import symbols
>>> from sympy.physics.mechanics import PlanarJoint, RigidBody, ReferenceFrame
>>> a, d, h = symbols('a d h')
First create bodies to represent the slope and the block.
>>> ground = RigidBody('G')
>>> block = RigidBody('B')
To define the slope you can either define the plane by specifying the
``planar_vectors`` or/and the ``rotation_axis``. However it is advisable to
create a rotated intermediate frame, so that the ``parent_vectors`` and
``rotation_axis`` will be the unit vectors of this intermediate frame.
>>> slope = ReferenceFrame('A')
>>> slope.orient_axis(ground.frame, ground.y, a)
The planar joint can be created using these bodies and intermediate frame.
We can specify the origin of the slope to be ``d`` above the slope's center
of mass and the block's center of mass to be a distance ``h`` above the
slope's surface. Note that we can specify the normal of the plane using the
rotation axis argument.
>>> joint = PlanarJoint('PC', ground, block, parent_point=d * ground.x,
... child_point=-h * block.x, parent_interframe=slope)
Once the joint is established the kinematics of the bodies can be accessed.
First the ``rotation_axis``, which is normal to the plane and the
``plane_vectors``, can be found.
>>> joint.rotation_axis
A.x
>>> joint.planar_vectors
[A.y, A.z]
The direction cosine matrix of the block with respect to the ground can be
found with:
>>> block.frame.dcm(ground.frame)
Matrix([
[ cos(a), 0, -sin(a)],
[sin(a)*sin(q0_PC(t)), cos(q0_PC(t)), sin(q0_PC(t))*cos(a)],
[sin(a)*cos(q0_PC(t)), -sin(q0_PC(t)), cos(a)*cos(q0_PC(t))]])
The angular velocity of the block can be computed with respect to the
ground.
>>> block.frame.ang_vel_in(ground.frame)
u0_PC(t)*A.x
The position of the block's center of mass can be found with:
>>> block.masscenter.pos_from(ground.masscenter)
d*G_frame.x + h*B_frame.x + q1_PC(t)*A.y + q2_PC(t)*A.z
Finally, the linear velocity of the block's center of mass can be
computed with respect to the ground.
>>> block.masscenter.vel(ground.frame)
u1_PC(t)*A.y + u2_PC(t)*A.z
In some cases it could be your preference to only define the normals of the
plane with respect to both bodies. This can most easily be done by supplying
vectors to the ``interframe`` arguments. What will happen in this case is
that an interframe will be created with its ``x`` axis aligned with the
provided vector. For a further explanation of how this is done see the notes
of the ``Joint`` class. In the code below, the above example (with the block
on the slope) is recreated by supplying vectors to the interframe arguments.
Note that the previously described option is however more computationally
efficient, because the algorithm now has to compute the rotation angle
between the provided vector and the 'x' axis.
>>> from sympy import symbols, cos, sin
>>> from sympy.physics.mechanics import PlanarJoint, RigidBody
>>> a, d, h = symbols('a d h')
>>> ground = RigidBody('G')
>>> block = RigidBody('B')
>>> joint = PlanarJoint(
... 'PC', ground, block, parent_point=d * ground.x,
... child_point=-h * block.x, child_interframe=block.x,
... parent_interframe=cos(a) * ground.x + sin(a) * ground.z)
>>> block.frame.dcm(ground.frame).simplify()
Matrix([
[ cos(a), 0, sin(a)],
[-sin(a)*sin(q0_PC(t)), cos(q0_PC(t)), sin(q0_PC(t))*cos(a)],
[-sin(a)*cos(q0_PC(t)), -sin(q0_PC(t)), cos(a)*cos(q0_PC(t))]])
"""
def __init__(self, name, parent, child, rotation_coordinate=None,
planar_coordinates=None, rotation_speed=None,
planar_speeds=None, parent_point=None, child_point=None,
parent_interframe=None, child_interframe=None):
# A ready to merge implementation of setting the planar_vectors and
# rotation_axis was added and removed in PR #24046
coordinates = (rotation_coordinate, planar_coordinates)
speeds = (rotation_speed, planar_speeds)
super().__init__(name, parent, child, coordinates, speeds,
parent_point, child_point,
parent_interframe=parent_interframe,
child_interframe=child_interframe)
def __str__(self):
return (f'PlanarJoint: {self.name} parent: {self.parent} '
f'child: {self.child}')
@property
def rotation_coordinate(self):
"""Generalized coordinate corresponding to the rotation angle."""
return self.coordinates[0]
@property
def planar_coordinates(self):
"""Two generalized coordinates used for the planar translation."""
return self.coordinates[1:, 0]
@property
def rotation_speed(self):
"""Generalized speed corresponding to the angular velocity."""
return self.speeds[0]
@property
def planar_speeds(self):
"""Two generalized speeds used for the planar translation velocity."""
return self.speeds[1:, 0]
@property
def rotation_axis(self):
"""The axis about which the rotation occurs."""
return self.parent_interframe.x
@property
def planar_vectors(self):
"""The vectors that describe the planar translation directions."""
return [self.parent_interframe.y, self.parent_interframe.z]
def _generate_coordinates(self, coordinates):
rotation_speed = self._fill_coordinate_list(coordinates[0], 1, 'q',
number_single=True)
planar_speeds = self._fill_coordinate_list(coordinates[1], 2, 'q', 1)
return rotation_speed.col_join(planar_speeds)
def _generate_speeds(self, speeds):
rotation_speed = self._fill_coordinate_list(speeds[0], 1, 'u',
number_single=True)
planar_speeds = self._fill_coordinate_list(speeds[1], 2, 'u', 1)
return rotation_speed.col_join(planar_speeds)
def _orient_frames(self):
self.child_interframe.orient_axis(
self.parent_interframe, self.rotation_axis,
self.rotation_coordinate)
def _set_angular_velocity(self):
self.child_interframe.set_ang_vel(
self.parent_interframe,
self.rotation_speed * self.rotation_axis)
def _set_linear_velocity(self):
self.child_point.set_pos(
self.parent_point,
self.planar_coordinates[0] * self.planar_vectors[0] +
self.planar_coordinates[1] * self.planar_vectors[1])
self.parent_point.set_vel(self.parent_interframe, 0)
self.child_point.set_vel(self.child_interframe, 0)
self.child_point.set_vel(
self._parent_frame, self.planar_speeds[0] * self.planar_vectors[0] +
self.planar_speeds[1] * self.planar_vectors[1])
self.child.masscenter.v2pt_theory(self.child_point, self._parent_frame,
self._child_frame)
class SphericalJoint(Joint):
"""Spherical (Ball-and-Socket) Joint.
.. image:: SphericalJoint.svg
:align: center
:width: 600
Explanation
===========
A spherical joint is defined such that the child body is free to rotate in
any direction, without allowing a translation of the ``child_point``. As can
also be seen in the image, the ``parent_point`` and ``child_point`` are
fixed on top of each other, i.e. the ``joint_point``. This rotation is
defined using the :func:`parent_interframe.orient(child_interframe,
rot_type, amounts, rot_order)
<sympy.physics.vector.frame.ReferenceFrame.orient>` method. The default
rotation consists of three relative rotations, i.e. body-fixed rotations.
Based on the direction cosine matrix following from these rotations, the
angular velocity is computed based on the generalized coordinates and
generalized speeds.
Parameters
==========
name : string
A unique name for the joint.
parent : Particle or RigidBody or Body
The parent body of joint.
child : Particle or RigidBody or Body
The child body of joint.
coordinates: iterable of dynamicsymbols, optional
Generalized coordinates of the joint.
speeds : iterable of dynamicsymbols, optional
Generalized speeds of joint.
parent_point : Point or Vector, optional
Attachment point where the joint is fixed to the parent body. If a
vector is provided, then the attachment point is computed by adding the
vector to the body's mass center. The default value is the parent's mass
center.
child_point : Point or Vector, optional
Attachment point where the joint is fixed to the child body. If a
vector is provided, then the attachment point is computed by adding the
vector to the body's mass center. The default value is the child's mass
center.
parent_interframe : ReferenceFrame, optional
Intermediate frame of the parent body with respect to which the joint
transformation is formulated. If a Vector is provided then an interframe
is created which aligns its X axis with the given vector. The default
value is the parent's own frame.
child_interframe : ReferenceFrame, optional
Intermediate frame of the child body with respect to which the joint
transformation is formulated. If a Vector is provided then an interframe
is created which aligns its X axis with the given vector. The default
value is the child's own frame.
rot_type : str, optional
The method used to generate the direction cosine matrix. Supported
methods are:
- ``'Body'``: three successive rotations about new intermediate axes,
also called "Euler and Tait-Bryan angles"
- ``'Space'``: three successive rotations about the parent frames' unit
vectors
The default method is ``'Body'``.
amounts :
Expressions defining the rotation angles or direction cosine matrix.
These must match the ``rot_type``. See examples below for details. The
input types are:
- ``'Body'``: 3-tuple of expressions, symbols, or functions
- ``'Space'``: 3-tuple of expressions, symbols, or functions
The default amounts are the given ``coordinates``.
rot_order : str or int, optional
If applicable, the order of the successive of rotations. The string
``'123'`` and integer ``123`` are equivalent, for example. Required for
``'Body'`` and ``'Space'``. The default value is ``123``.
Attributes
==========
name : string
The joint's name.
parent : Particle or RigidBody or Body
The joint's parent body.
child : Particle or RigidBody or Body
The joint's child body.
coordinates : Matrix
Matrix of the joint's generalized coordinates.
speeds : Matrix
Matrix of the joint's generalized speeds.
parent_point : Point
Attachment point where the joint is fixed to the parent body.
child_point : Point
Attachment point where the joint is fixed to the child body.
parent_interframe : ReferenceFrame
Intermediate frame of the parent body with respect to which the joint
transformation is formulated.
child_interframe : ReferenceFrame
Intermediate frame of the child body with respect to which the joint
transformation is formulated.
kdes : Matrix
Kinematical differential equations of the joint.
Examples
=========
A single spherical joint is created from two bodies and has the following
basic attributes:
>>> from sympy.physics.mechanics import RigidBody, SphericalJoint
>>> parent = RigidBody('P')
>>> parent
P
>>> child = RigidBody('C')
>>> child
C
>>> joint = SphericalJoint('PC', parent, child)
>>> joint
SphericalJoint: PC parent: P child: C
>>> joint.name
'PC'
>>> joint.parent
P
>>> joint.child
C
>>> joint.parent_point
P_masscenter
>>> joint.child_point
C_masscenter
>>> joint.parent_interframe
P_frame
>>> joint.child_interframe
C_frame
>>> joint.coordinates
Matrix([
[q0_PC(t)],
[q1_PC(t)],
[q2_PC(t)]])
>>> joint.speeds
Matrix([
[u0_PC(t)],
[u1_PC(t)],
[u2_PC(t)]])
>>> child.frame.ang_vel_in(parent.frame).to_matrix(child.frame)
Matrix([
[ u0_PC(t)*cos(q1_PC(t))*cos(q2_PC(t)) + u1_PC(t)*sin(q2_PC(t))],
[-u0_PC(t)*sin(q2_PC(t))*cos(q1_PC(t)) + u1_PC(t)*cos(q2_PC(t))],
[ u0_PC(t)*sin(q1_PC(t)) + u2_PC(t)]])
>>> child.frame.x.to_matrix(parent.frame)
Matrix([
[ cos(q1_PC(t))*cos(q2_PC(t))],
[sin(q0_PC(t))*sin(q1_PC(t))*cos(q2_PC(t)) + sin(q2_PC(t))*cos(q0_PC(t))],
[sin(q0_PC(t))*sin(q2_PC(t)) - sin(q1_PC(t))*cos(q0_PC(t))*cos(q2_PC(t))]])
>>> joint.child_point.pos_from(joint.parent_point)
0
To further demonstrate the use of the spherical joint, the kinematics of a
spherical joint with a ZXZ rotation can be created as follows.
>>> from sympy import symbols
>>> from sympy.physics.mechanics import RigidBody, SphericalJoint
>>> l1 = symbols('l1')
First create bodies to represent the fixed floor and a pendulum bob.
>>> floor = RigidBody('F')
>>> bob = RigidBody('B')
The joint will connect the bob to the floor, with the joint located at a
distance of ``l1`` from the child's center of mass and the rotation set to a
body-fixed ZXZ rotation.
>>> joint = SphericalJoint('S', floor, bob, child_point=l1 * bob.y,
... rot_type='body', rot_order='ZXZ')
Now that the joint is established, the kinematics of the connected body can
be accessed.
The position of the bob's masscenter is found with:
>>> bob.masscenter.pos_from(floor.masscenter)
- l1*B_frame.y
The angular velocities of the pendulum link can be computed with respect to
the floor.
>>> bob.frame.ang_vel_in(floor.frame).to_matrix(
... floor.frame).simplify()
Matrix([
[u1_S(t)*cos(q0_S(t)) + u2_S(t)*sin(q0_S(t))*sin(q1_S(t))],
[u1_S(t)*sin(q0_S(t)) - u2_S(t)*sin(q1_S(t))*cos(q0_S(t))],
[ u0_S(t) + u2_S(t)*cos(q1_S(t))]])
Finally, the linear velocity of the bob's center of mass can be computed.
>>> bob.masscenter.vel(floor.frame).to_matrix(bob.frame)
Matrix([
[ l1*(u0_S(t)*cos(q1_S(t)) + u2_S(t))],
[ 0],
[-l1*(u0_S(t)*sin(q1_S(t))*sin(q2_S(t)) + u1_S(t)*cos(q2_S(t)))]])
"""
def __init__(self, name, parent, child, coordinates=None, speeds=None,
parent_point=None, child_point=None, parent_interframe=None,
child_interframe=None, rot_type='BODY', amounts=None,
rot_order=123):
self._rot_type = rot_type
self._amounts = amounts
self._rot_order = rot_order
super().__init__(name, parent, child, coordinates, speeds,
parent_point, child_point,
parent_interframe=parent_interframe,
child_interframe=child_interframe)
def __str__(self):
return (f'SphericalJoint: {self.name} parent: {self.parent} '
f'child: {self.child}')
def _generate_coordinates(self, coordinates):
return self._fill_coordinate_list(coordinates, 3, 'q')
def _generate_speeds(self, speeds):
return self._fill_coordinate_list(speeds, len(self.coordinates), 'u')
def _orient_frames(self):
supported_rot_types = ('BODY', 'SPACE')
if self._rot_type.upper() not in supported_rot_types:
raise NotImplementedError(
f'Rotation type "{self._rot_type}" is not implemented. '
f'Implemented rotation types are: {supported_rot_types}')
amounts = self.coordinates if self._amounts is None else self._amounts
self.child_interframe.orient(self.parent_interframe, self._rot_type,
amounts, self._rot_order)
def _set_angular_velocity(self):
t = dynamicsymbols._t
vel = self.child_interframe.ang_vel_in(self.parent_interframe).xreplace(
{q.diff(t): u for q, u in zip(self.coordinates, self.speeds)}
)
self.child_interframe.set_ang_vel(self.parent_interframe, vel)
def _set_linear_velocity(self):
self.child_point.set_pos(self.parent_point, 0)
self.parent_point.set_vel(self._parent_frame, 0)
self.child_point.set_vel(self._child_frame, 0)
self.child.masscenter.v2pt_theory(self.parent_point, self._parent_frame,
self._child_frame)
class WeldJoint(Joint):
"""Weld Joint.
.. raw:: html
:file: ../../../doc/src/modules/physics/mechanics/api/WeldJoint.svg
Explanation
===========
A weld joint is defined such that there is no relative motion between the
child and parent bodies. The direction cosine matrix between the attachment
frame (``parent_interframe`` and ``child_interframe``) is the identity
matrix and the attachment points (``parent_point`` and ``child_point``) are
coincident. The page on the joints framework gives a more detailed
explanation of the intermediate frames.
Parameters
==========
name : string
A unique name for the joint.
parent : Particle or RigidBody or Body
The parent body of joint.
child : Particle or RigidBody or Body
The child body of joint.
parent_point : Point or Vector, optional
Attachment point where the joint is fixed to the parent body. If a
vector is provided, then the attachment point is computed by adding the
vector to the body's mass center. The default value is the parent's mass
center.
child_point : Point or Vector, optional
Attachment point where the joint is fixed to the child body. If a
vector is provided, then the attachment point is computed by adding the
vector to the body's mass center. The default value is the child's mass
center.
parent_interframe : ReferenceFrame, optional
Intermediate frame of the parent body with respect to which the joint
transformation is formulated. If a Vector is provided then an interframe
is created which aligns its X axis with the given vector. The default
value is the parent's own frame.
child_interframe : ReferenceFrame, optional
Intermediate frame of the child body with respect to which the joint
transformation is formulated. If a Vector is provided then an interframe
is created which aligns its X axis with the given vector. The default
value is the child's own frame.
Attributes
==========
name : string
The joint's name.
parent : Particle or RigidBody or Body
The joint's parent body.
child : Particle or RigidBody or Body
The joint's child body.
coordinates : Matrix
Matrix of the joint's generalized coordinates. The default value is
``dynamicsymbols(f'q_{joint.name}')``.
speeds : Matrix
Matrix of the joint's generalized speeds. The default value is
``dynamicsymbols(f'u_{joint.name}')``.
parent_point : Point
Attachment point where the joint is fixed to the parent body.
child_point : Point
Attachment point where the joint is fixed to the child body.
parent_interframe : ReferenceFrame
Intermediate frame of the parent body with respect to which the joint
transformation is formulated.
child_interframe : ReferenceFrame
Intermediate frame of the child body with respect to which the joint
transformation is formulated.
kdes : Matrix
Kinematical differential equations of the joint.
Examples
=========
A single weld joint is created from two bodies and has the following basic
attributes:
>>> from sympy.physics.mechanics import RigidBody, WeldJoint
>>> parent = RigidBody('P')
>>> parent
P
>>> child = RigidBody('C')
>>> child
C
>>> joint = WeldJoint('PC', parent, child)
>>> joint
WeldJoint: PC parent: P child: C
>>> joint.name
'PC'
>>> joint.parent
P
>>> joint.child
C
>>> joint.parent_point
P_masscenter
>>> joint.child_point
C_masscenter
>>> joint.coordinates
Matrix(0, 0, [])
>>> joint.speeds
Matrix(0, 0, [])
>>> child.frame.ang_vel_in(parent.frame)
0
>>> child.frame.dcm(parent.frame)
Matrix([
[1, 0, 0],
[0, 1, 0],
[0, 0, 1]])
>>> joint.child_point.pos_from(joint.parent_point)
0
To further demonstrate the use of the weld joint, two relatively-fixed
bodies rotated by a quarter turn about the Y axis can be created as follows:
>>> from sympy import symbols, pi
>>> from sympy.physics.mechanics import ReferenceFrame, RigidBody, WeldJoint
>>> l1, l2 = symbols('l1 l2')
First create the bodies to represent the parent and rotated child body.
>>> parent = RigidBody('P')
>>> child = RigidBody('C')
Next the intermediate frame specifying the fixed rotation with respect to
the parent can be created.
>>> rotated_frame = ReferenceFrame('Pr')
>>> rotated_frame.orient_axis(parent.frame, parent.y, pi / 2)
The weld between the parent body and child body is located at a distance
``l1`` from the parent's center of mass in the X direction and ``l2`` from
the child's center of mass in the child's negative X direction.
>>> weld = WeldJoint('weld', parent, child, parent_point=l1 * parent.x,
... child_point=-l2 * child.x,
... parent_interframe=rotated_frame)
Now that the joint has been established, the kinematics of the bodies can be
accessed. The direction cosine matrix of the child body with respect to the
parent can be found:
>>> child.frame.dcm(parent.frame)
Matrix([
[0, 0, -1],
[0, 1, 0],
[1, 0, 0]])
As can also been seen from the direction cosine matrix, the parent X axis is
aligned with the child's Z axis:
>>> parent.x == child.z
True
The position of the child's center of mass with respect to the parent's
center of mass can be found with:
>>> child.masscenter.pos_from(parent.masscenter)
l1*P_frame.x + l2*C_frame.x
The angular velocity of the child with respect to the parent is 0 as one
would expect.
>>> child.frame.ang_vel_in(parent.frame)
0
"""
def __init__(self, name, parent, child, parent_point=None, child_point=None,
parent_interframe=None, child_interframe=None):
super().__init__(name, parent, child, [], [], parent_point,
child_point, parent_interframe=parent_interframe,
child_interframe=child_interframe)
self._kdes = Matrix(1, 0, []).T # Removes stackability problems #10770
def __str__(self):
return (f'WeldJoint: {self.name} parent: {self.parent} '
f'child: {self.child}')
def _generate_coordinates(self, coordinate):
return Matrix()
def _generate_speeds(self, speed):
return Matrix()
def _orient_frames(self):
self.child_interframe.orient_axis(self.parent_interframe,
self.parent_interframe.x, 0)
def _set_angular_velocity(self):
self.child_interframe.set_ang_vel(self.parent_interframe, 0)
def _set_linear_velocity(self):
self.child_point.set_pos(self.parent_point, 0)
self.parent_point.set_vel(self._parent_frame, 0)
self.child_point.set_vel(self._child_frame, 0)
self.child.masscenter.set_vel(self._parent_frame, 0)
PK ]ZZZ깟�( �( ' sympy/physics/mechanics/jointsmethod.pyfrom sympy.physics.mechanics import (Body, Lagrangian, KanesMethod, LagrangesMethod,
RigidBody, Particle)
from sympy.physics.mechanics.body_base import BodyBase
from sympy.physics.mechanics.method import _Methods
from sympy import Matrix
from sympy.utilities.exceptions import sympy_deprecation_warning
__all__ = ['JointsMethod']
class JointsMethod(_Methods):
"""Method for formulating the equations of motion using a set of interconnected bodies with joints.
.. deprecated:: 1.13
The JointsMethod class is deprecated. Its functionality has been
replaced by the new :class:`~.System` class.
Parameters
==========
newtonion : Body or ReferenceFrame
The newtonion(inertial) frame.
*joints : Joint
The joints in the system
Attributes
==========
q, u : iterable
Iterable of the generalized coordinates and speeds
bodies : iterable
Iterable of Body objects in the system.
loads : iterable
Iterable of (Point, vector) or (ReferenceFrame, vector) tuples
describing the forces on the system.
mass_matrix : Matrix, shape(n, n)
The system's mass matrix
forcing : Matrix, shape(n, 1)
The system's forcing vector
mass_matrix_full : Matrix, shape(2*n, 2*n)
The "mass matrix" for the u's and q's
forcing_full : Matrix, shape(2*n, 1)
The "forcing vector" for the u's and q's
method : KanesMethod or Lagrange's method
Method's object.
kdes : iterable
Iterable of kde in they system.
Examples
========
As Body and JointsMethod have been deprecated, the following examples are
for illustrative purposes only. The functionality of Body is fully captured
by :class:`~.RigidBody` and :class:`~.Particle` and the functionality of
JointsMethod is fully captured by :class:`~.System`. To ignore the
deprecation warning we can use the ignore_warnings context manager.
>>> from sympy.utilities.exceptions import ignore_warnings
This is a simple example for a one degree of freedom translational
spring-mass-damper.
>>> from sympy import symbols
>>> from sympy.physics.mechanics import Body, JointsMethod, PrismaticJoint
>>> from sympy.physics.vector import dynamicsymbols
>>> c, k = symbols('c k')
>>> x, v = dynamicsymbols('x v')
>>> with ignore_warnings(DeprecationWarning):
... wall = Body('W')
... body = Body('B')
>>> J = PrismaticJoint('J', wall, body, coordinates=x, speeds=v)
>>> wall.apply_force(c*v*wall.x, reaction_body=body)
>>> wall.apply_force(k*x*wall.x, reaction_body=body)
>>> with ignore_warnings(DeprecationWarning):
... method = JointsMethod(wall, J)
>>> method.form_eoms()
Matrix([[-B_mass*Derivative(v(t), t) - c*v(t) - k*x(t)]])
>>> M = method.mass_matrix_full
>>> F = method.forcing_full
>>> rhs = M.LUsolve(F)
>>> rhs
Matrix([
[ v(t)],
[(-c*v(t) - k*x(t))/B_mass]])
Notes
=====
``JointsMethod`` currently only works with systems that do not have any
configuration or motion constraints.
"""
def __init__(self, newtonion, *joints):
sympy_deprecation_warning(
"""
The JointsMethod class is deprecated.
Its functionality has been replaced by the new System class.
""",
deprecated_since_version="1.13",
active_deprecations_target="deprecated-mechanics-jointsmethod"
)
if isinstance(newtonion, BodyBase):
self.frame = newtonion.frame
else:
self.frame = newtonion
self._joints = joints
self._bodies = self._generate_bodylist()
self._loads = self._generate_loadlist()
self._q = self._generate_q()
self._u = self._generate_u()
self._kdes = self._generate_kdes()
self._method = None
@property
def bodies(self):
"""List of bodies in they system."""
return self._bodies
@property
def loads(self):
"""List of loads on the system."""
return self._loads
@property
def q(self):
"""List of the generalized coordinates."""
return self._q
@property
def u(self):
"""List of the generalized speeds."""
return self._u
@property
def kdes(self):
"""List of the generalized coordinates."""
return self._kdes
@property
def forcing_full(self):
"""The "forcing vector" for the u's and q's."""
return self.method.forcing_full
@property
def mass_matrix_full(self):
"""The "mass matrix" for the u's and q's."""
return self.method.mass_matrix_full
@property
def mass_matrix(self):
"""The system's mass matrix."""
return self.method.mass_matrix
@property
def forcing(self):
"""The system's forcing vector."""
return self.method.forcing
@property
def method(self):
"""Object of method used to form equations of systems."""
return self._method
def _generate_bodylist(self):
bodies = []
for joint in self._joints:
if joint.child not in bodies:
bodies.append(joint.child)
if joint.parent not in bodies:
bodies.append(joint.parent)
return bodies
def _generate_loadlist(self):
load_list = []
for body in self.bodies:
if isinstance(body, Body):
load_list.extend(body.loads)
return load_list
def _generate_q(self):
q_ind = []
for joint in self._joints:
for coordinate in joint.coordinates:
if coordinate in q_ind:
raise ValueError('Coordinates of joints should be unique.')
q_ind.append(coordinate)
return Matrix(q_ind)
def _generate_u(self):
u_ind = []
for joint in self._joints:
for speed in joint.speeds:
if speed in u_ind:
raise ValueError('Speeds of joints should be unique.')
u_ind.append(speed)
return Matrix(u_ind)
def _generate_kdes(self):
kd_ind = Matrix(1, 0, []).T
for joint in self._joints:
kd_ind = kd_ind.col_join(joint.kdes)
return kd_ind
def _convert_bodies(self):
# Convert `Body` to `Particle` and `RigidBody`
bodylist = []
for body in self.bodies:
if not isinstance(body, Body):
bodylist.append(body)
continue
if body.is_rigidbody:
rb = RigidBody(body.name, body.masscenter, body.frame, body.mass,
(body.central_inertia, body.masscenter))
rb.potential_energy = body.potential_energy
bodylist.append(rb)
else:
part = Particle(body.name, body.masscenter, body.mass)
part.potential_energy = body.potential_energy
bodylist.append(part)
return bodylist
def form_eoms(self, method=KanesMethod):
"""Method to form system's equation of motions.
Parameters
==========
method : Class
Class name of method.
Returns
========
Matrix
Vector of equations of motions.
Examples
========
As Body and JointsMethod have been deprecated, the following examples
are for illustrative purposes only. The functionality of Body is fully
captured by :class:`~.RigidBody` and :class:`~.Particle` and the
functionality of JointsMethod is fully captured by :class:`~.System`. To
ignore the deprecation warning we can use the ignore_warnings context
manager.
>>> from sympy.utilities.exceptions import ignore_warnings
This is a simple example for a one degree of freedom translational
spring-mass-damper.
>>> from sympy import S, symbols
>>> from sympy.physics.mechanics import LagrangesMethod, dynamicsymbols, Body
>>> from sympy.physics.mechanics import PrismaticJoint, JointsMethod
>>> q = dynamicsymbols('q')
>>> qd = dynamicsymbols('q', 1)
>>> m, k, b = symbols('m k b')
>>> with ignore_warnings(DeprecationWarning):
... wall = Body('W')
... part = Body('P', mass=m)
>>> part.potential_energy = k * q**2 / S(2)
>>> J = PrismaticJoint('J', wall, part, coordinates=q, speeds=qd)
>>> wall.apply_force(b * qd * wall.x, reaction_body=part)
>>> with ignore_warnings(DeprecationWarning):
... method = JointsMethod(wall, J)
>>> method.form_eoms(LagrangesMethod)
Matrix([[b*Derivative(q(t), t) + k*q(t) + m*Derivative(q(t), (t, 2))]])
We can also solve for the states using the 'rhs' method.
>>> method.rhs()
Matrix([
[ Derivative(q(t), t)],
[(-b*Derivative(q(t), t) - k*q(t))/m]])
"""
bodylist = self._convert_bodies()
if issubclass(method, LagrangesMethod): #LagrangesMethod or similar
L = Lagrangian(self.frame, *bodylist)
self._method = method(L, self.q, self.loads, bodylist, self.frame)
else: #KanesMethod or similar
self._method = method(self.frame, q_ind=self.q, u_ind=self.u, kd_eqs=self.kdes,
forcelist=self.loads, bodies=bodylist)
soln = self.method._form_eoms()
return soln
def rhs(self, inv_method=None):
"""Returns equations that can be solved numerically.
Parameters
==========
inv_method : str
The specific sympy inverse matrix calculation method to use. For a
list of valid methods, see
:meth:`~sympy.matrices.matrixbase.MatrixBase.inv`
Returns
========
Matrix
Numerically solvable equations.
See Also
========
sympy.physics.mechanics.kane.KanesMethod.rhs:
KanesMethod's rhs function.
sympy.physics.mechanics.lagrange.LagrangesMethod.rhs:
LagrangesMethod's rhs function.
"""
return self.method.rhs(inv_method=inv_method)
PK ]ZZZg� 3� 3� sympy/physics/mechanics/kane.pyfrom sympy import zeros, Matrix, diff, eye
from sympy.core.sorting import default_sort_key
from sympy.physics.vector import (ReferenceFrame, dynamicsymbols,
partial_velocity)
from sympy.physics.mechanics.method import _Methods
from sympy.physics.mechanics.particle import Particle
from sympy.physics.mechanics.rigidbody import RigidBody
from sympy.physics.mechanics.functions import (msubs, find_dynamicsymbols,
_f_list_parser,
_validate_coordinates,
_parse_linear_solver)
from sympy.physics.mechanics.linearize import Linearizer
from sympy.utilities.iterables import iterable
__all__ = ['KanesMethod']
class KanesMethod(_Methods):
r"""Kane's method object.
Explanation
===========
This object is used to do the "book-keeping" as you go through and form
equations of motion in the way Kane presents in:
Kane, T., Levinson, D. Dynamics Theory and Applications. 1985 McGraw-Hill
The attributes are for equations in the form [M] udot = forcing.
Attributes
==========
q, u : Matrix
Matrices of the generalized coordinates and speeds
bodies : iterable
Iterable of Particle and RigidBody objects in the system.
loads : iterable
Iterable of (Point, vector) or (ReferenceFrame, vector) tuples
describing the forces on the system.
auxiliary_eqs : Matrix
If applicable, the set of auxiliary Kane's
equations used to solve for non-contributing
forces.
mass_matrix : Matrix
The system's dynamics mass matrix: [k_d; k_dnh]
forcing : Matrix
The system's dynamics forcing vector: -[f_d; f_dnh]
mass_matrix_kin : Matrix
The "mass matrix" for kinematic differential equations: k_kqdot
forcing_kin : Matrix
The forcing vector for kinematic differential equations: -(k_ku*u + f_k)
mass_matrix_full : Matrix
The "mass matrix" for the u's and q's with dynamics and kinematics
forcing_full : Matrix
The "forcing vector" for the u's and q's with dynamics and kinematics
Parameters
==========
frame : ReferenceFrame
The inertial reference frame for the system.
q_ind : iterable of dynamicsymbols
Independent generalized coordinates.
u_ind : iterable of dynamicsymbols
Independent generalized speeds.
kd_eqs : iterable of Expr, optional
Kinematic differential equations, which linearly relate the generalized
speeds to the time-derivatives of the generalized coordinates.
q_dependent : iterable of dynamicsymbols, optional
Dependent generalized coordinates.
configuration_constraints : iterable of Expr, optional
Constraints on the system's configuration, i.e. holonomic constraints.
u_dependent : iterable of dynamicsymbols, optional
Dependent generalized speeds.
velocity_constraints : iterable of Expr, optional
Constraints on the system's velocity, i.e. the combination of the
nonholonomic constraints and the time-derivative of the holonomic
constraints.
acceleration_constraints : iterable of Expr, optional
Constraints on the system's acceleration, by default these are the
time-derivative of the velocity constraints.
u_auxiliary : iterable of dynamicsymbols, optional
Auxiliary generalized speeds.
bodies : iterable of Particle and/or RigidBody, optional
The particles and rigid bodies in the system.
forcelist : iterable of tuple[Point | ReferenceFrame, Vector], optional
Forces and torques applied on the system.
explicit_kinematics : bool
Boolean whether the mass matrices and forcing vectors should use the
explicit form (default) or implicit form for kinematics.
See the notes for more details.
kd_eqs_solver : str, callable
Method used to solve the kinematic differential equations. If a string
is supplied, it should be a valid method that can be used with the
:meth:`sympy.matrices.matrixbase.MatrixBase.solve`. If a callable is
supplied, it should have the format ``f(A, rhs)``, where it solves the
equations and returns the solution. The default utilizes LU solve. See
the notes for more information.
constraint_solver : str, callable
Method used to solve the velocity constraints. If a string is
supplied, it should be a valid method that can be used with the
:meth:`sympy.matrices.matrixbase.MatrixBase.solve`. If a callable is
supplied, it should have the format ``f(A, rhs)``, where it solves the
equations and returns the solution. The default utilizes LU solve. See
the notes for more information.
Notes
=====
The mass matrices and forcing vectors related to kinematic equations
are given in the explicit form by default. In other words, the kinematic
mass matrix is $\mathbf{k_{k\dot{q}}} = \mathbf{I}$.
In order to get the implicit form of those matrices/vectors, you can set the
``explicit_kinematics`` attribute to ``False``. So $\mathbf{k_{k\dot{q}}}$
is not necessarily an identity matrix. This can provide more compact
equations for non-simple kinematics.
Two linear solvers can be supplied to ``KanesMethod``: one for solving the
kinematic differential equations and one to solve the velocity constraints.
Both of these sets of equations can be expressed as a linear system ``Ax = rhs``,
which have to be solved in order to obtain the equations of motion.
The default solver ``'LU'``, which stands for LU solve, results relatively low
number of operations. The weakness of this method is that it can result in zero
division errors.
If zero divisions are encountered, a possible solver which may solve the problem
is ``"CRAMER"``. This method uses Cramer's rule to solve the system. This method
is slower and results in more operations than the default solver. However it only
uses a single division by default per entry of the solution.
While a valid list of solvers can be found at
:meth:`sympy.matrices.matrixbase.MatrixBase.solve`, it is also possible to supply a
`callable`. This way it is possible to use a different solver routine. If the
kinematic differential equations are not too complex it can be worth it to simplify
the solution by using ``lambda A, b: simplify(Matrix.LUsolve(A, b))``. Another
option solver one may use is :func:`sympy.solvers.solveset.linsolve`. This can be
done using `lambda A, b: tuple(linsolve((A, b)))[0]`, where we select the first
solution as our system should have only one unique solution.
Examples
========
This is a simple example for a one degree of freedom translational
spring-mass-damper.
In this example, we first need to do the kinematics.
This involves creating generalized speeds and coordinates and their
derivatives.
Then we create a point and set its velocity in a frame.
>>> from sympy import symbols
>>> from sympy.physics.mechanics import dynamicsymbols, ReferenceFrame
>>> from sympy.physics.mechanics import Point, Particle, KanesMethod
>>> q, u = dynamicsymbols('q u')
>>> qd, ud = dynamicsymbols('q u', 1)
>>> m, c, k = symbols('m c k')
>>> N = ReferenceFrame('N')
>>> P = Point('P')
>>> P.set_vel(N, u * N.x)
Next we need to arrange/store information in the way that KanesMethod
requires. The kinematic differential equations should be an iterable of
expressions. A list of forces/torques must be constructed, where each entry
in the list is a (Point, Vector) or (ReferenceFrame, Vector) tuple, where
the Vectors represent the Force or Torque.
Next a particle needs to be created, and it needs to have a point and mass
assigned to it.
Finally, a list of all bodies and particles needs to be created.
>>> kd = [qd - u]
>>> FL = [(P, (-k * q - c * u) * N.x)]
>>> pa = Particle('pa', P, m)
>>> BL = [pa]
Finally we can generate the equations of motion.
First we create the KanesMethod object and supply an inertial frame,
coordinates, generalized speeds, and the kinematic differential equations.
Additional quantities such as configuration and motion constraints,
dependent coordinates and speeds, and auxiliary speeds are also supplied
here (see the online documentation).
Next we form FR* and FR to complete: Fr + Fr* = 0.
We have the equations of motion at this point.
It makes sense to rearrange them though, so we calculate the mass matrix and
the forcing terms, for E.o.M. in the form: [MM] udot = forcing, where MM is
the mass matrix, udot is a vector of the time derivatives of the
generalized speeds, and forcing is a vector representing "forcing" terms.
>>> KM = KanesMethod(N, q_ind=[q], u_ind=[u], kd_eqs=kd)
>>> (fr, frstar) = KM.kanes_equations(BL, FL)
>>> MM = KM.mass_matrix
>>> forcing = KM.forcing
>>> rhs = MM.inv() * forcing
>>> rhs
Matrix([[(-c*u(t) - k*q(t))/m]])
>>> KM.linearize(A_and_B=True)[0]
Matrix([
[ 0, 1],
[-k/m, -c/m]])
Please look at the documentation pages for more information on how to
perform linearization and how to deal with dependent coordinates & speeds,
and how do deal with bringing non-contributing forces into evidence.
"""
def __init__(self, frame, q_ind, u_ind, kd_eqs=None, q_dependent=None,
configuration_constraints=None, u_dependent=None,
velocity_constraints=None, acceleration_constraints=None,
u_auxiliary=None, bodies=None, forcelist=None,
explicit_kinematics=True, kd_eqs_solver='LU',
constraint_solver='LU'):
"""Please read the online documentation. """
if not q_ind:
q_ind = [dynamicsymbols('dummy_q')]
kd_eqs = [dynamicsymbols('dummy_kd')]
if not isinstance(frame, ReferenceFrame):
raise TypeError('An inertial ReferenceFrame must be supplied')
self._inertial = frame
self._fr = None
self._frstar = None
self._forcelist = forcelist
self._bodylist = bodies
self.explicit_kinematics = explicit_kinematics
self._constraint_solver = constraint_solver
self._initialize_vectors(q_ind, q_dependent, u_ind, u_dependent,
u_auxiliary)
_validate_coordinates(self.q, self.u)
self._initialize_kindiffeq_matrices(kd_eqs, kd_eqs_solver)
self._initialize_constraint_matrices(
configuration_constraints, velocity_constraints,
acceleration_constraints, constraint_solver)
def _initialize_vectors(self, q_ind, q_dep, u_ind, u_dep, u_aux):
"""Initialize the coordinate and speed vectors."""
none_handler = lambda x: Matrix(x) if x else Matrix()
# Initialize generalized coordinates
q_dep = none_handler(q_dep)
if not iterable(q_ind):
raise TypeError('Generalized coordinates must be an iterable.')
if not iterable(q_dep):
raise TypeError('Dependent coordinates must be an iterable.')
q_ind = Matrix(q_ind)
self._qdep = q_dep
self._q = Matrix([q_ind, q_dep])
self._qdot = self.q.diff(dynamicsymbols._t)
# Initialize generalized speeds
u_dep = none_handler(u_dep)
if not iterable(u_ind):
raise TypeError('Generalized speeds must be an iterable.')
if not iterable(u_dep):
raise TypeError('Dependent speeds must be an iterable.')
u_ind = Matrix(u_ind)
self._udep = u_dep
self._u = Matrix([u_ind, u_dep])
self._udot = self.u.diff(dynamicsymbols._t)
self._uaux = none_handler(u_aux)
def _initialize_constraint_matrices(self, config, vel, acc, linear_solver='LU'):
"""Initializes constraint matrices."""
linear_solver = _parse_linear_solver(linear_solver)
# Define vector dimensions
o = len(self.u)
m = len(self._udep)
p = o - m
none_handler = lambda x: Matrix(x) if x else Matrix()
# Initialize configuration constraints
config = none_handler(config)
if len(self._qdep) != len(config):
raise ValueError('There must be an equal number of dependent '
'coordinates and configuration constraints.')
self._f_h = none_handler(config)
# Initialize velocity and acceleration constraints
vel = none_handler(vel)
acc = none_handler(acc)
if len(vel) != m:
raise ValueError('There must be an equal number of dependent '
'speeds and velocity constraints.')
if acc and (len(acc) != m):
raise ValueError('There must be an equal number of dependent '
'speeds and acceleration constraints.')
if vel:
u_zero = dict.fromkeys(self.u, 0)
udot_zero = dict.fromkeys(self._udot, 0)
# When calling kanes_equations, another class instance will be
# created if auxiliary u's are present. In this case, the
# computation of kinetic differential equation matrices will be
# skipped as this was computed during the original KanesMethod
# object, and the qd_u_map will not be available.
if self._qdot_u_map is not None:
vel = msubs(vel, self._qdot_u_map)
self._f_nh = msubs(vel, u_zero)
self._k_nh = (vel - self._f_nh).jacobian(self.u)
# If no acceleration constraints given, calculate them.
if not acc:
_f_dnh = (self._k_nh.diff(dynamicsymbols._t) * self.u +
self._f_nh.diff(dynamicsymbols._t))
if self._qdot_u_map is not None:
_f_dnh = msubs(_f_dnh, self._qdot_u_map)
self._f_dnh = _f_dnh
self._k_dnh = self._k_nh
else:
if self._qdot_u_map is not None:
acc = msubs(acc, self._qdot_u_map)
self._f_dnh = msubs(acc, udot_zero)
self._k_dnh = (acc - self._f_dnh).jacobian(self._udot)
# Form of non-holonomic constraints is B*u + C = 0.
# We partition B into independent and dependent columns:
# Ars is then -B_dep.inv() * B_ind, and it relates dependent speeds
# to independent speeds as: udep = Ars*uind, neglecting the C term.
B_ind = self._k_nh[:, :p]
B_dep = self._k_nh[:, p:o]
self._Ars = -linear_solver(B_dep, B_ind)
else:
self._f_nh = Matrix()
self._k_nh = Matrix()
self._f_dnh = Matrix()
self._k_dnh = Matrix()
self._Ars = Matrix()
def _initialize_kindiffeq_matrices(self, kdeqs, linear_solver='LU'):
"""Initialize the kinematic differential equation matrices.
Parameters
==========
kdeqs : sequence of sympy expressions
Kinematic differential equations in the form of f(u,q',q,t) where
f() = 0. The equations have to be linear in the generalized
coordinates and generalized speeds.
"""
linear_solver = _parse_linear_solver(linear_solver)
if kdeqs:
if len(self.q) != len(kdeqs):
raise ValueError('There must be an equal number of kinematic '
'differential equations and coordinates.')
u = self.u
qdot = self._qdot
kdeqs = Matrix(kdeqs)
u_zero = dict.fromkeys(u, 0)
uaux_zero = dict.fromkeys(self._uaux, 0)
qdot_zero = dict.fromkeys(qdot, 0)
# Extract the linear coefficient matrices as per the following
# equation:
#
# k_ku(q,t)*u(t) + k_kqdot(q,t)*q'(t) + f_k(q,t) = 0
#
k_ku = kdeqs.jacobian(u)
k_kqdot = kdeqs.jacobian(qdot)
f_k = kdeqs.xreplace(u_zero).xreplace(qdot_zero)
# The kinematic differential equations should be linear in both q'
# and u, so check for u and q' in the components.
dy_syms = find_dynamicsymbols(k_ku.row_join(k_kqdot).row_join(f_k))
nonlin_vars = [vari for vari in u[:] + qdot[:] if vari in dy_syms]
if nonlin_vars:
msg = ('The provided kinematic differential equations are '
'nonlinear in {}. They must be linear in the '
'generalized speeds and derivatives of the generalized '
'coordinates.')
raise ValueError(msg.format(nonlin_vars))
self._f_k_implicit = f_k.xreplace(uaux_zero)
self._k_ku_implicit = k_ku.xreplace(uaux_zero)
self._k_kqdot_implicit = k_kqdot
# Solve for q'(t) such that the coefficient matrices are now in
# this form:
#
# k_kqdot^-1*k_ku*u(t) + I*q'(t) + k_kqdot^-1*f_k = 0
#
# NOTE : Solving the kinematic differential equations here is not
# necessary and prevents the equations from being provided in fully
# implicit form.
f_k_explicit = linear_solver(k_kqdot, f_k)
k_ku_explicit = linear_solver(k_kqdot, k_ku)
self._qdot_u_map = dict(zip(qdot, -(k_ku_explicit*u + f_k_explicit)))
self._f_k = f_k_explicit.xreplace(uaux_zero)
self._k_ku = k_ku_explicit.xreplace(uaux_zero)
self._k_kqdot = eye(len(qdot))
else:
self._qdot_u_map = None
self._f_k_implicit = self._f_k = Matrix()
self._k_ku_implicit = self._k_ku = Matrix()
self._k_kqdot_implicit = self._k_kqdot = Matrix()
def _form_fr(self, fl):
"""Form the generalized active force."""
if fl is not None and (len(fl) == 0 or not iterable(fl)):
raise ValueError('Force pairs must be supplied in an '
'non-empty iterable or None.')
N = self._inertial
# pull out relevant velocities for constructing partial velocities
vel_list, f_list = _f_list_parser(fl, N)
vel_list = [msubs(i, self._qdot_u_map) for i in vel_list]
f_list = [msubs(i, self._qdot_u_map) for i in f_list]
# Fill Fr with dot product of partial velocities and forces
o = len(self.u)
b = len(f_list)
FR = zeros(o, 1)
partials = partial_velocity(vel_list, self.u, N)
for i in range(o):
FR[i] = sum(partials[j][i].dot(f_list[j]) for j in range(b))
# In case there are dependent speeds
if self._udep:
p = o - len(self._udep)
FRtilde = FR[:p, 0]
FRold = FR[p:o, 0]
FRtilde += self._Ars.T * FRold
FR = FRtilde
self._forcelist = fl
self._fr = FR
return FR
def _form_frstar(self, bl):
"""Form the generalized inertia force."""
if not iterable(bl):
raise TypeError('Bodies must be supplied in an iterable.')
t = dynamicsymbols._t
N = self._inertial
# Dicts setting things to zero
udot_zero = dict.fromkeys(self._udot, 0)
uaux_zero = dict.fromkeys(self._uaux, 0)
uauxdot = [diff(i, t) for i in self._uaux]
uauxdot_zero = dict.fromkeys(uauxdot, 0)
# Dictionary of q' and q'' to u and u'
q_ddot_u_map = {k.diff(t): v.diff(t).xreplace(
self._qdot_u_map) for (k, v) in self._qdot_u_map.items()}
q_ddot_u_map.update(self._qdot_u_map)
# Fill up the list of partials: format is a list with num elements
# equal to number of entries in body list. Each of these elements is a
# list - either of length 1 for the translational components of
# particles or of length 2 for the translational and rotational
# components of rigid bodies. The inner most list is the list of
# partial velocities.
def get_partial_velocity(body):
if isinstance(body, RigidBody):
vlist = [body.masscenter.vel(N), body.frame.ang_vel_in(N)]
elif isinstance(body, Particle):
vlist = [body.point.vel(N),]
else:
raise TypeError('The body list may only contain either '
'RigidBody or Particle as list elements.')
v = [msubs(vel, self._qdot_u_map) for vel in vlist]
return partial_velocity(v, self.u, N)
partials = [get_partial_velocity(body) for body in bl]
# Compute fr_star in two components:
# fr_star = -(MM*u' + nonMM)
o = len(self.u)
MM = zeros(o, o)
nonMM = zeros(o, 1)
zero_uaux = lambda expr: msubs(expr, uaux_zero)
zero_udot_uaux = lambda expr: msubs(msubs(expr, udot_zero), uaux_zero)
for i, body in enumerate(bl):
if isinstance(body, RigidBody):
M = zero_uaux(body.mass)
I = zero_uaux(body.central_inertia)
vel = zero_uaux(body.masscenter.vel(N))
omega = zero_uaux(body.frame.ang_vel_in(N))
acc = zero_udot_uaux(body.masscenter.acc(N))
inertial_force = (M.diff(t) * vel + M * acc)
inertial_torque = zero_uaux((I.dt(body.frame).dot(omega)) +
msubs(I.dot(body.frame.ang_acc_in(N)), udot_zero) +
(omega.cross(I.dot(omega))))
for j in range(o):
tmp_vel = zero_uaux(partials[i][0][j])
tmp_ang = zero_uaux(I.dot(partials[i][1][j]))
for k in range(o):
# translational
MM[j, k] += M*tmp_vel.dot(partials[i][0][k])
# rotational
MM[j, k] += tmp_ang.dot(partials[i][1][k])
nonMM[j] += inertial_force.dot(partials[i][0][j])
nonMM[j] += inertial_torque.dot(partials[i][1][j])
else:
M = zero_uaux(body.mass)
vel = zero_uaux(body.point.vel(N))
acc = zero_udot_uaux(body.point.acc(N))
inertial_force = (M.diff(t) * vel + M * acc)
for j in range(o):
temp = zero_uaux(partials[i][0][j])
for k in range(o):
MM[j, k] += M*temp.dot(partials[i][0][k])
nonMM[j] += inertial_force.dot(partials[i][0][j])
# Compose fr_star out of MM and nonMM
MM = zero_uaux(msubs(MM, q_ddot_u_map))
nonMM = msubs(msubs(nonMM, q_ddot_u_map),
udot_zero, uauxdot_zero, uaux_zero)
fr_star = -(MM * msubs(Matrix(self._udot), uauxdot_zero) + nonMM)
# If there are dependent speeds, we need to find fr_star_tilde
if self._udep:
p = o - len(self._udep)
fr_star_ind = fr_star[:p, 0]
fr_star_dep = fr_star[p:o, 0]
fr_star = fr_star_ind + (self._Ars.T * fr_star_dep)
# Apply the same to MM
MMi = MM[:p, :]
MMd = MM[p:o, :]
MM = MMi + (self._Ars.T * MMd)
# Apply the same to nonMM
nonMM = nonMM[:p, :] + (self._Ars.T * nonMM[p:o, :])
self._bodylist = bl
self._frstar = fr_star
self._k_d = MM
self._f_d = -(self._fr - nonMM)
return fr_star
def to_linearizer(self, linear_solver='LU'):
"""Returns an instance of the Linearizer class, initiated from the
data in the KanesMethod class. This may be more desirable than using
the linearize class method, as the Linearizer object will allow more
efficient recalculation (i.e. about varying operating points).
Parameters
==========
linear_solver : str, callable
Method used to solve the several symbolic linear systems of the
form ``A*x=b`` in the linearization process. If a string is
supplied, it should be a valid method that can be used with the
:meth:`sympy.matrices.matrixbase.MatrixBase.solve`. If a callable is
supplied, it should have the format ``x = f(A, b)``, where it
solves the equations and returns the solution. The default is
``'LU'`` which corresponds to SymPy's ``A.LUsolve(b)``.
``LUsolve()`` is fast to compute but will often result in
divide-by-zero and thus ``nan`` results.
Returns
=======
Linearizer
An instantiated
:class:`sympy.physics.mechanics.linearize.Linearizer`.
"""
if (self._fr is None) or (self._frstar is None):
raise ValueError('Need to compute Fr, Fr* first.')
# Get required equation components. The Kane's method class breaks
# these into pieces. Need to reassemble
f_c = self._f_h
if self._f_nh and self._k_nh:
f_v = self._f_nh + self._k_nh*Matrix(self.u)
else:
f_v = Matrix()
if self._f_dnh and self._k_dnh:
f_a = self._f_dnh + self._k_dnh*Matrix(self._udot)
else:
f_a = Matrix()
# Dicts to sub to zero, for splitting up expressions
u_zero = dict.fromkeys(self.u, 0)
ud_zero = dict.fromkeys(self._udot, 0)
qd_zero = dict.fromkeys(self._qdot, 0)
qd_u_zero = dict.fromkeys(Matrix([self._qdot, self.u]), 0)
# Break the kinematic differential eqs apart into f_0 and f_1
f_0 = msubs(self._f_k, u_zero) + self._k_kqdot*Matrix(self._qdot)
f_1 = msubs(self._f_k, qd_zero) + self._k_ku*Matrix(self.u)
# Break the dynamic differential eqs into f_2 and f_3
f_2 = msubs(self._frstar, qd_u_zero)
f_3 = msubs(self._frstar, ud_zero) + self._fr
f_4 = zeros(len(f_2), 1)
# Get the required vector components
q = self.q
u = self.u
if self._qdep:
q_i = q[:-len(self._qdep)]
else:
q_i = q
q_d = self._qdep
if self._udep:
u_i = u[:-len(self._udep)]
else:
u_i = u
u_d = self._udep
# Form dictionary to set auxiliary speeds & their derivatives to 0.
uaux = self._uaux
uauxdot = uaux.diff(dynamicsymbols._t)
uaux_zero = dict.fromkeys(Matrix([uaux, uauxdot]), 0)
# Checking for dynamic symbols outside the dynamic differential
# equations; throws error if there is.
sym_list = set(Matrix([q, self._qdot, u, self._udot, uaux, uauxdot]))
if any(find_dynamicsymbols(i, sym_list) for i in [self._k_kqdot,
self._k_ku, self._f_k, self._k_dnh, self._f_dnh, self._k_d]):
raise ValueError('Cannot have dynamicsymbols outside dynamic \
forcing vector.')
# Find all other dynamic symbols, forming the forcing vector r.
# Sort r to make it canonical.
r = list(find_dynamicsymbols(msubs(self._f_d, uaux_zero), sym_list))
r.sort(key=default_sort_key)
# Check for any derivatives of variables in r that are also found in r.
for i in r:
if diff(i, dynamicsymbols._t) in r:
raise ValueError('Cannot have derivatives of specified \
quantities when linearizing forcing terms.')
return Linearizer(f_0, f_1, f_2, f_3, f_4, f_c, f_v, f_a, q, u, q_i,
q_d, u_i, u_d, r, linear_solver=linear_solver)
# TODO : Remove `new_method` after 1.1 has been released.
def linearize(self, *, new_method=None, linear_solver='LU', **kwargs):
""" Linearize the equations of motion about a symbolic operating point.
Parameters
==========
new_method
Deprecated, does nothing and will be removed.
linear_solver : str, callable
Method used to solve the several symbolic linear systems of the
form ``A*x=b`` in the linearization process. If a string is
supplied, it should be a valid method that can be used with the
:meth:`sympy.matrices.matrixbase.MatrixBase.solve`. If a callable is
supplied, it should have the format ``x = f(A, b)``, where it
solves the equations and returns the solution. The default is
``'LU'`` which corresponds to SymPy's ``A.LUsolve(b)``.
``LUsolve()`` is fast to compute but will often result in
divide-by-zero and thus ``nan`` results.
**kwargs
Extra keyword arguments are passed to
:meth:`sympy.physics.mechanics.linearize.Linearizer.linearize`.
Explanation
===========
If kwarg A_and_B is False (default), returns M, A, B, r for the
linearized form, M*[q', u']^T = A*[q_ind, u_ind]^T + B*r.
If kwarg A_and_B is True, returns A, B, r for the linearized form
dx = A*x + B*r, where x = [q_ind, u_ind]^T. Note that this is
computationally intensive if there are many symbolic parameters. For
this reason, it may be more desirable to use the default A_and_B=False,
returning M, A, and B. Values may then be substituted in to these
matrices, and the state space form found as
A = P.T*M.inv()*A, B = P.T*M.inv()*B, where P = Linearizer.perm_mat.
In both cases, r is found as all dynamicsymbols in the equations of
motion that are not part of q, u, q', or u'. They are sorted in
canonical form.
The operating points may be also entered using the ``op_point`` kwarg.
This takes a dictionary of {symbol: value}, or a an iterable of such
dictionaries. The values may be numeric or symbolic. The more values
you can specify beforehand, the faster this computation will run.
For more documentation, please see the ``Linearizer`` class.
"""
linearizer = self.to_linearizer(linear_solver=linear_solver)
result = linearizer.linearize(**kwargs)
return result + (linearizer.r,)
def kanes_equations(self, bodies=None, loads=None):
""" Method to form Kane's equations, Fr + Fr* = 0.
Explanation
===========
Returns (Fr, Fr*). In the case where auxiliary generalized speeds are
present (say, s auxiliary speeds, o generalized speeds, and m motion
constraints) the length of the returned vectors will be o - m + s in
length. The first o - m equations will be the constrained Kane's
equations, then the s auxiliary Kane's equations. These auxiliary
equations can be accessed with the auxiliary_eqs property.
Parameters
==========
bodies : iterable
An iterable of all RigidBody's and Particle's in the system.
A system must have at least one body.
loads : iterable
Takes in an iterable of (Particle, Vector) or (ReferenceFrame, Vector)
tuples which represent the force at a point or torque on a frame.
Must be either a non-empty iterable of tuples or None which corresponds
to a system with no constraints.
"""
if bodies is None:
bodies = self.bodies
if loads is None and self._forcelist is not None:
loads = self._forcelist
if loads == []:
loads = None
if not self._k_kqdot:
raise AttributeError('Create an instance of KanesMethod with '
'kinematic differential equations to use this method.')
fr = self._form_fr(loads)
frstar = self._form_frstar(bodies)
if self._uaux:
if not self._udep:
km = KanesMethod(self._inertial, self.q, self._uaux,
u_auxiliary=self._uaux, constraint_solver=self._constraint_solver)
else:
km = KanesMethod(self._inertial, self.q, self._uaux,
u_auxiliary=self._uaux, u_dependent=self._udep,
velocity_constraints=(self._k_nh * self.u +
self._f_nh),
acceleration_constraints=(self._k_dnh * self._udot +
self._f_dnh),
constraint_solver=self._constraint_solver
)
km._qdot_u_map = self._qdot_u_map
self._km = km
fraux = km._form_fr(loads)
frstaraux = km._form_frstar(bodies)
self._aux_eq = fraux + frstaraux
self._fr = fr.col_join(fraux)
self._frstar = frstar.col_join(frstaraux)
return (self._fr, self._frstar)
def _form_eoms(self):
fr, frstar = self.kanes_equations(self.bodylist, self.forcelist)
return fr + frstar
def rhs(self, inv_method=None):
"""Returns the system's equations of motion in first order form. The
output is the right hand side of::
x' = |q'| =: f(q, u, r, p, t)
|u'|
The right hand side is what is needed by most numerical ODE
integrators.
Parameters
==========
inv_method : str
The specific sympy inverse matrix calculation method to use. For a
list of valid methods, see
:meth:`~sympy.matrices.matrixbase.MatrixBase.inv`
"""
rhs = zeros(len(self.q) + len(self.u), 1)
kdes = self.kindiffdict()
for i, q_i in enumerate(self.q):
rhs[i] = kdes[q_i.diff()]
if inv_method is None:
rhs[len(self.q):, 0] = self.mass_matrix.LUsolve(self.forcing)
else:
rhs[len(self.q):, 0] = (self.mass_matrix.inv(inv_method,
try_block_diag=True) *
self.forcing)
return rhs
def kindiffdict(self):
"""Returns a dictionary mapping q' to u."""
if not self._qdot_u_map:
raise AttributeError('Create an instance of KanesMethod with '
'kinematic differential equations to use this method.')
return self._qdot_u_map
@property
def auxiliary_eqs(self):
"""A matrix containing the auxiliary equations."""
if not self._fr or not self._frstar:
raise ValueError('Need to compute Fr, Fr* first.')
if not self._uaux:
raise ValueError('No auxiliary speeds have been declared.')
return self._aux_eq
@property
def mass_matrix_kin(self):
r"""The kinematic "mass matrix" $\mathbf{k_{k\dot{q}}}$ of the system."""
return self._k_kqdot if self.explicit_kinematics else self._k_kqdot_implicit
@property
def forcing_kin(self):
"""The kinematic "forcing vector" of the system."""
if self.explicit_kinematics:
return -(self._k_ku * Matrix(self.u) + self._f_k)
else:
return -(self._k_ku_implicit * Matrix(self.u) + self._f_k_implicit)
@property
def mass_matrix(self):
"""The mass matrix of the system."""
if not self._fr or not self._frstar:
raise ValueError('Need to compute Fr, Fr* first.')
return Matrix([self._k_d, self._k_dnh])
@property
def forcing(self):
"""The forcing vector of the system."""
if not self._fr or not self._frstar:
raise ValueError('Need to compute Fr, Fr* first.')
return -Matrix([self._f_d, self._f_dnh])
@property
def mass_matrix_full(self):
"""The mass matrix of the system, augmented by the kinematic
differential equations in explicit or implicit form."""
if not self._fr or not self._frstar:
raise ValueError('Need to compute Fr, Fr* first.')
o, n = len(self.u), len(self.q)
return (self.mass_matrix_kin.row_join(zeros(n, o))).col_join(
zeros(o, n).row_join(self.mass_matrix))
@property
def forcing_full(self):
"""The forcing vector of the system, augmented by the kinematic
differential equations in explicit or implicit form."""
return Matrix([self.forcing_kin, self.forcing])
@property
def q(self):
return self._q
@property
def u(self):
return self._u
@property
def bodylist(self):
return self._bodylist
@property
def forcelist(self):
return self._forcelist
@property
def bodies(self):
return self._bodylist
@property
def loads(self):
return self._forcelist
PK ]ZZZ��<�N �N # sympy/physics/mechanics/lagrange.pyfrom sympy import diff, zeros, Matrix, eye, sympify
from sympy.core.sorting import default_sort_key
from sympy.physics.vector import dynamicsymbols, ReferenceFrame
from sympy.physics.mechanics.method import _Methods
from sympy.physics.mechanics.functions import (
find_dynamicsymbols, msubs, _f_list_parser, _validate_coordinates)
from sympy.physics.mechanics.linearize import Linearizer
from sympy.utilities.iterables import iterable
__all__ = ['LagrangesMethod']
class LagrangesMethod(_Methods):
"""Lagrange's method object.
Explanation
===========
This object generates the equations of motion in a two step procedure. The
first step involves the initialization of LagrangesMethod by supplying the
Lagrangian and the generalized coordinates, at the bare minimum. If there
are any constraint equations, they can be supplied as keyword arguments.
The Lagrange multipliers are automatically generated and are equal in
number to the constraint equations. Similarly any non-conservative forces
can be supplied in an iterable (as described below and also shown in the
example) along with a ReferenceFrame. This is also discussed further in the
__init__ method.
Attributes
==========
q, u : Matrix
Matrices of the generalized coordinates and speeds
loads : iterable
Iterable of (Point, vector) or (ReferenceFrame, vector) tuples
describing the forces on the system.
bodies : iterable
Iterable containing the rigid bodies and particles of the system.
mass_matrix : Matrix
The system's mass matrix
forcing : Matrix
The system's forcing vector
mass_matrix_full : Matrix
The "mass matrix" for the qdot's, qdoubledot's, and the
lagrange multipliers (lam)
forcing_full : Matrix
The forcing vector for the qdot's, qdoubledot's and
lagrange multipliers (lam)
Examples
========
This is a simple example for a one degree of freedom translational
spring-mass-damper.
In this example, we first need to do the kinematics.
This involves creating generalized coordinates and their derivatives.
Then we create a point and set its velocity in a frame.
>>> from sympy.physics.mechanics import LagrangesMethod, Lagrangian
>>> from sympy.physics.mechanics import ReferenceFrame, Particle, Point
>>> from sympy.physics.mechanics import dynamicsymbols
>>> from sympy import symbols
>>> q = dynamicsymbols('q')
>>> qd = dynamicsymbols('q', 1)
>>> m, k, b = symbols('m k b')
>>> N = ReferenceFrame('N')
>>> P = Point('P')
>>> P.set_vel(N, qd * N.x)
We need to then prepare the information as required by LagrangesMethod to
generate equations of motion.
First we create the Particle, which has a point attached to it.
Following this the lagrangian is created from the kinetic and potential
energies.
Then, an iterable of nonconservative forces/torques must be constructed,
where each item is a (Point, Vector) or (ReferenceFrame, Vector) tuple,
with the Vectors representing the nonconservative forces or torques.
>>> Pa = Particle('Pa', P, m)
>>> Pa.potential_energy = k * q**2 / 2.0
>>> L = Lagrangian(N, Pa)
>>> fl = [(P, -b * qd * N.x)]
Finally we can generate the equations of motion.
First we create the LagrangesMethod object. To do this one must supply
the Lagrangian, and the generalized coordinates. The constraint equations,
the forcelist, and the inertial frame may also be provided, if relevant.
Next we generate Lagrange's equations of motion, such that:
Lagrange's equations of motion = 0.
We have the equations of motion at this point.
>>> l = LagrangesMethod(L, [q], forcelist = fl, frame = N)
>>> print(l.form_lagranges_equations())
Matrix([[b*Derivative(q(t), t) + 1.0*k*q(t) + m*Derivative(q(t), (t, 2))]])
We can also solve for the states using the 'rhs' method.
>>> print(l.rhs())
Matrix([[Derivative(q(t), t)], [(-b*Derivative(q(t), t) - 1.0*k*q(t))/m]])
Please refer to the docstrings on each method for more details.
"""
def __init__(self, Lagrangian, qs, forcelist=None, bodies=None, frame=None,
hol_coneqs=None, nonhol_coneqs=None):
"""Supply the following for the initialization of LagrangesMethod.
Lagrangian : Sympifyable
qs : array_like
The generalized coordinates
hol_coneqs : array_like, optional
The holonomic constraint equations
nonhol_coneqs : array_like, optional
The nonholonomic constraint equations
forcelist : iterable, optional
Takes an iterable of (Point, Vector) or (ReferenceFrame, Vector)
tuples which represent the force at a point or torque on a frame.
This feature is primarily to account for the nonconservative forces
and/or moments.
bodies : iterable, optional
Takes an iterable containing the rigid bodies and particles of the
system.
frame : ReferenceFrame, optional
Supply the inertial frame. This is used to determine the
generalized forces due to non-conservative forces.
"""
self._L = Matrix([sympify(Lagrangian)])
self.eom = None
self._m_cd = Matrix() # Mass Matrix of differentiated coneqs
self._m_d = Matrix() # Mass Matrix of dynamic equations
self._f_cd = Matrix() # Forcing part of the diff coneqs
self._f_d = Matrix() # Forcing part of the dynamic equations
self.lam_coeffs = Matrix() # The coeffecients of the multipliers
forcelist = forcelist if forcelist else []
if not iterable(forcelist):
raise TypeError('Force pairs must be supplied in an iterable.')
self._forcelist = forcelist
if frame and not isinstance(frame, ReferenceFrame):
raise TypeError('frame must be a valid ReferenceFrame')
self._bodies = bodies
self.inertial = frame
self.lam_vec = Matrix()
self._term1 = Matrix()
self._term2 = Matrix()
self._term3 = Matrix()
self._term4 = Matrix()
# Creating the qs, qdots and qdoubledots
if not iterable(qs):
raise TypeError('Generalized coordinates must be an iterable')
self._q = Matrix(qs)
self._qdots = self.q.diff(dynamicsymbols._t)
self._qdoubledots = self._qdots.diff(dynamicsymbols._t)
_validate_coordinates(self.q)
mat_build = lambda x: Matrix(x) if x else Matrix()
hol_coneqs = mat_build(hol_coneqs)
nonhol_coneqs = mat_build(nonhol_coneqs)
self.coneqs = Matrix([hol_coneqs.diff(dynamicsymbols._t),
nonhol_coneqs])
self._hol_coneqs = hol_coneqs
def form_lagranges_equations(self):
"""Method to form Lagrange's equations of motion.
Returns a vector of equations of motion using Lagrange's equations of
the second kind.
"""
qds = self._qdots
qdd_zero = dict.fromkeys(self._qdoubledots, 0)
n = len(self.q)
# Internally we represent the EOM as four terms:
# EOM = term1 - term2 - term3 - term4 = 0
# First term
self._term1 = self._L.jacobian(qds)
self._term1 = self._term1.diff(dynamicsymbols._t).T
# Second term
self._term2 = self._L.jacobian(self.q).T
# Third term
if self.coneqs:
coneqs = self.coneqs
m = len(coneqs)
# Creating the multipliers
self.lam_vec = Matrix(dynamicsymbols('lam1:' + str(m + 1)))
self.lam_coeffs = -coneqs.jacobian(qds)
self._term3 = self.lam_coeffs.T * self.lam_vec
# Extracting the coeffecients of the qdds from the diff coneqs
diffconeqs = coneqs.diff(dynamicsymbols._t)
self._m_cd = diffconeqs.jacobian(self._qdoubledots)
# The remaining terms i.e. the 'forcing' terms in diff coneqs
self._f_cd = -diffconeqs.subs(qdd_zero)
else:
self._term3 = zeros(n, 1)
# Fourth term
if self.forcelist:
N = self.inertial
self._term4 = zeros(n, 1)
for i, qd in enumerate(qds):
flist = zip(*_f_list_parser(self.forcelist, N))
self._term4[i] = sum(v.diff(qd, N).dot(f) for (v, f) in flist)
else:
self._term4 = zeros(n, 1)
# Form the dynamic mass and forcing matrices
without_lam = self._term1 - self._term2 - self._term4
self._m_d = without_lam.jacobian(self._qdoubledots)
self._f_d = -without_lam.subs(qdd_zero)
# Form the EOM
self.eom = without_lam - self._term3
return self.eom
def _form_eoms(self):
return self.form_lagranges_equations()
@property
def mass_matrix(self):
"""Returns the mass matrix, which is augmented by the Lagrange
multipliers, if necessary.
Explanation
===========
If the system is described by 'n' generalized coordinates and there are
no constraint equations then an n X n matrix is returned.
If there are 'n' generalized coordinates and 'm' constraint equations
have been supplied during initialization then an n X (n+m) matrix is
returned. The (n + m - 1)th and (n + m)th columns contain the
coefficients of the Lagrange multipliers.
"""
if self.eom is None:
raise ValueError('Need to compute the equations of motion first')
if self.coneqs:
return (self._m_d).row_join(self.lam_coeffs.T)
else:
return self._m_d
@property
def mass_matrix_full(self):
"""Augments the coefficients of qdots to the mass_matrix."""
if self.eom is None:
raise ValueError('Need to compute the equations of motion first')
n = len(self.q)
m = len(self.coneqs)
row1 = eye(n).row_join(zeros(n, n + m))
row2 = zeros(n, n).row_join(self.mass_matrix)
if self.coneqs:
row3 = zeros(m, n).row_join(self._m_cd).row_join(zeros(m, m))
return row1.col_join(row2).col_join(row3)
else:
return row1.col_join(row2)
@property
def forcing(self):
"""Returns the forcing vector from 'lagranges_equations' method."""
if self.eom is None:
raise ValueError('Need to compute the equations of motion first')
return self._f_d
@property
def forcing_full(self):
"""Augments qdots to the forcing vector above."""
if self.eom is None:
raise ValueError('Need to compute the equations of motion first')
if self.coneqs:
return self._qdots.col_join(self.forcing).col_join(self._f_cd)
else:
return self._qdots.col_join(self.forcing)
def to_linearizer(self, q_ind=None, qd_ind=None, q_dep=None, qd_dep=None,
linear_solver='LU'):
"""Returns an instance of the Linearizer class, initiated from the data
in the LagrangesMethod class. This may be more desirable than using the
linearize class method, as the Linearizer object will allow more
efficient recalculation (i.e. about varying operating points).
Parameters
==========
q_ind, qd_ind : array_like, optional
The independent generalized coordinates and speeds.
q_dep, qd_dep : array_like, optional
The dependent generalized coordinates and speeds.
linear_solver : str, callable
Method used to solve the several symbolic linear systems of the
form ``A*x=b`` in the linearization process. If a string is
supplied, it should be a valid method that can be used with the
:meth:`sympy.matrices.matrixbase.MatrixBase.solve`. If a callable is
supplied, it should have the format ``x = f(A, b)``, where it
solves the equations and returns the solution. The default is
``'LU'`` which corresponds to SymPy's ``A.LUsolve(b)``.
``LUsolve()`` is fast to compute but will often result in
divide-by-zero and thus ``nan`` results.
Returns
=======
Linearizer
An instantiated
:class:`sympy.physics.mechanics.linearize.Linearizer`.
"""
# Compose vectors
t = dynamicsymbols._t
q = self.q
u = self._qdots
ud = u.diff(t)
# Get vector of lagrange multipliers
lams = self.lam_vec
mat_build = lambda x: Matrix(x) if x else Matrix()
q_i = mat_build(q_ind)
q_d = mat_build(q_dep)
u_i = mat_build(qd_ind)
u_d = mat_build(qd_dep)
# Compose general form equations
f_c = self._hol_coneqs
f_v = self.coneqs
f_a = f_v.diff(t)
f_0 = u
f_1 = -u
f_2 = self._term1
f_3 = -(self._term2 + self._term4)
f_4 = -self._term3
# Check that there are an appropriate number of independent and
# dependent coordinates
if len(q_d) != len(f_c) or len(u_d) != len(f_v):
raise ValueError(("Must supply {:} dependent coordinates, and " +
"{:} dependent speeds").format(len(f_c), len(f_v)))
if set(Matrix([q_i, q_d])) != set(q):
raise ValueError("Must partition q into q_ind and q_dep, with " +
"no extra or missing symbols.")
if set(Matrix([u_i, u_d])) != set(u):
raise ValueError("Must partition qd into qd_ind and qd_dep, " +
"with no extra or missing symbols.")
# Find all other dynamic symbols, forming the forcing vector r.
# Sort r to make it canonical.
insyms = set(Matrix([q, u, ud, lams]))
r = list(find_dynamicsymbols(f_3, insyms))
r.sort(key=default_sort_key)
# Check for any derivatives of variables in r that are also found in r.
for i in r:
if diff(i, dynamicsymbols._t) in r:
raise ValueError('Cannot have derivatives of specified \
quantities when linearizing forcing terms.')
return Linearizer(f_0, f_1, f_2, f_3, f_4, f_c, f_v, f_a, q, u, q_i,
q_d, u_i, u_d, r, lams, linear_solver=linear_solver)
def linearize(self, q_ind=None, qd_ind=None, q_dep=None, qd_dep=None,
linear_solver='LU', **kwargs):
"""Linearize the equations of motion about a symbolic operating point.
Parameters
==========
linear_solver : str, callable
Method used to solve the several symbolic linear systems of the
form ``A*x=b`` in the linearization process. If a string is
supplied, it should be a valid method that can be used with the
:meth:`sympy.matrices.matrixbase.MatrixBase.solve`. If a callable is
supplied, it should have the format ``x = f(A, b)``, where it
solves the equations and returns the solution. The default is
``'LU'`` which corresponds to SymPy's ``A.LUsolve(b)``.
``LUsolve()`` is fast to compute but will often result in
divide-by-zero and thus ``nan`` results.
**kwargs
Extra keyword arguments are passed to
:meth:`sympy.physics.mechanics.linearize.Linearizer.linearize`.
Explanation
===========
If kwarg A_and_B is False (default), returns M, A, B, r for the
linearized form, M*[q', u']^T = A*[q_ind, u_ind]^T + B*r.
If kwarg A_and_B is True, returns A, B, r for the linearized form
dx = A*x + B*r, where x = [q_ind, u_ind]^T. Note that this is
computationally intensive if there are many symbolic parameters. For
this reason, it may be more desirable to use the default A_and_B=False,
returning M, A, and B. Values may then be substituted in to these
matrices, and the state space form found as
A = P.T*M.inv()*A, B = P.T*M.inv()*B, where P = Linearizer.perm_mat.
In both cases, r is found as all dynamicsymbols in the equations of
motion that are not part of q, u, q', or u'. They are sorted in
canonical form.
The operating points may be also entered using the ``op_point`` kwarg.
This takes a dictionary of {symbol: value}, or a an iterable of such
dictionaries. The values may be numeric or symbolic. The more values
you can specify beforehand, the faster this computation will run.
For more documentation, please see the ``Linearizer`` class."""
linearizer = self.to_linearizer(q_ind, qd_ind, q_dep, qd_dep,
linear_solver=linear_solver)
result = linearizer.linearize(**kwargs)
return result + (linearizer.r,)
def solve_multipliers(self, op_point=None, sol_type='dict'):
"""Solves for the values of the lagrange multipliers symbolically at
the specified operating point.
Parameters
==========
op_point : dict or iterable of dicts, optional
Point at which to solve at. The operating point is specified as
a dictionary or iterable of dictionaries of {symbol: value}. The
value may be numeric or symbolic itself.
sol_type : str, optional
Solution return type. Valid options are:
- 'dict': A dict of {symbol : value} (default)
- 'Matrix': An ordered column matrix of the solution
"""
# Determine number of multipliers
k = len(self.lam_vec)
if k == 0:
raise ValueError("System has no lagrange multipliers to solve for.")
# Compose dict of operating conditions
if isinstance(op_point, dict):
op_point_dict = op_point
elif iterable(op_point):
op_point_dict = {}
for op in op_point:
op_point_dict.update(op)
elif op_point is None:
op_point_dict = {}
else:
raise TypeError("op_point must be either a dictionary or an "
"iterable of dictionaries.")
# Compose the system to be solved
mass_matrix = self.mass_matrix.col_join(-self.lam_coeffs.row_join(
zeros(k, k)))
force_matrix = self.forcing.col_join(self._f_cd)
# Sub in the operating point
mass_matrix = msubs(mass_matrix, op_point_dict)
force_matrix = msubs(force_matrix, op_point_dict)
# Solve for the multipliers
sol_list = mass_matrix.LUsolve(-force_matrix)[-k:]
if sol_type == 'dict':
return dict(zip(self.lam_vec, sol_list))
elif sol_type == 'Matrix':
return Matrix(sol_list)
else:
raise ValueError("Unknown sol_type {:}.".format(sol_type))
def rhs(self, inv_method=None, **kwargs):
"""Returns equations that can be solved numerically.
Parameters
==========
inv_method : str
The specific sympy inverse matrix calculation method to use. For a
list of valid methods, see
:meth:`~sympy.matrices.matrixbase.MatrixBase.inv`
"""
if inv_method is None:
self._rhs = self.mass_matrix_full.LUsolve(self.forcing_full)
else:
self._rhs = (self.mass_matrix_full.inv(inv_method,
try_block_diag=True) * self.forcing_full)
return self._rhs
@property
def q(self):
return self._q
@property
def u(self):
return self._qdots
@property
def bodies(self):
return self._bodies
@property
def forcelist(self):
return self._forcelist
@property
def loads(self):
return self._forcelist
PK ]ZZZ�8��YC YC $ sympy/physics/mechanics/linearize.py__all__ = ['Linearizer']
from sympy import Matrix, eye, zeros
from sympy.core.symbol import Dummy
from sympy.utilities.iterables import flatten
from sympy.physics.vector import dynamicsymbols
from sympy.physics.mechanics.functions import msubs, _parse_linear_solver
from collections import namedtuple
from collections.abc import Iterable
class Linearizer:
"""This object holds the general model form for a dynamic system. This
model is used for computing the linearized form of the system, while
properly dealing with constraints leading to dependent coordinates and
speeds. The notation and method is described in [1]_.
Attributes
==========
f_0, f_1, f_2, f_3, f_4, f_c, f_v, f_a : Matrix
Matrices holding the general system form.
q, u, r : Matrix
Matrices holding the generalized coordinates, speeds, and
input vectors.
q_i, u_i : Matrix
Matrices of the independent generalized coordinates and speeds.
q_d, u_d : Matrix
Matrices of the dependent generalized coordinates and speeds.
perm_mat : Matrix
Permutation matrix such that [q_ind, u_ind]^T = perm_mat*[q, u]^T
References
==========
.. [1] D. L. Peterson, G. Gede, and M. Hubbard, "Symbolic linearization of
equations of motion of constrained multibody systems," Multibody
Syst Dyn, vol. 33, no. 2, pp. 143-161, Feb. 2015, doi:
10.1007/s11044-014-9436-5.
"""
def __init__(self, f_0, f_1, f_2, f_3, f_4, f_c, f_v, f_a, q, u, q_i=None,
q_d=None, u_i=None, u_d=None, r=None, lams=None,
linear_solver='LU'):
"""
Parameters
==========
f_0, f_1, f_2, f_3, f_4, f_c, f_v, f_a : array_like
System of equations holding the general system form.
Supply empty array or Matrix if the parameter
does not exist.
q : array_like
The generalized coordinates.
u : array_like
The generalized speeds
q_i, u_i : array_like, optional
The independent generalized coordinates and speeds.
q_d, u_d : array_like, optional
The dependent generalized coordinates and speeds.
r : array_like, optional
The input variables.
lams : array_like, optional
The lagrange multipliers
linear_solver : str, callable
Method used to solve the several symbolic linear systems of the
form ``A*x=b`` in the linearization process. If a string is
supplied, it should be a valid method that can be used with the
:meth:`sympy.matrices.matrixbase.MatrixBase.solve`. If a callable is
supplied, it should have the format ``x = f(A, b)``, where it
solves the equations and returns the solution. The default is
``'LU'`` which corresponds to SymPy's ``A.LUsolve(b)``.
``LUsolve()`` is fast to compute but will often result in
divide-by-zero and thus ``nan`` results.
"""
self.linear_solver = _parse_linear_solver(linear_solver)
# Generalized equation form
self.f_0 = Matrix(f_0)
self.f_1 = Matrix(f_1)
self.f_2 = Matrix(f_2)
self.f_3 = Matrix(f_3)
self.f_4 = Matrix(f_4)
self.f_c = Matrix(f_c)
self.f_v = Matrix(f_v)
self.f_a = Matrix(f_a)
# Generalized equation variables
self.q = Matrix(q)
self.u = Matrix(u)
none_handler = lambda x: Matrix(x) if x else Matrix()
self.q_i = none_handler(q_i)
self.q_d = none_handler(q_d)
self.u_i = none_handler(u_i)
self.u_d = none_handler(u_d)
self.r = none_handler(r)
self.lams = none_handler(lams)
# Derivatives of generalized equation variables
self._qd = self.q.diff(dynamicsymbols._t)
self._ud = self.u.diff(dynamicsymbols._t)
# If the user doesn't actually use generalized variables, and the
# qd and u vectors have any intersecting variables, this can cause
# problems. We'll fix this with some hackery, and Dummy variables
dup_vars = set(self._qd).intersection(self.u)
self._qd_dup = Matrix([var if var not in dup_vars else Dummy() for var
in self._qd])
# Derive dimesion terms
l = len(self.f_c)
m = len(self.f_v)
n = len(self.q)
o = len(self.u)
s = len(self.r)
k = len(self.lams)
dims = namedtuple('dims', ['l', 'm', 'n', 'o', 's', 'k'])
self._dims = dims(l, m, n, o, s, k)
self._Pq = None
self._Pqi = None
self._Pqd = None
self._Pu = None
self._Pui = None
self._Pud = None
self._C_0 = None
self._C_1 = None
self._C_2 = None
self.perm_mat = None
self._setup_done = False
def _setup(self):
# Calculations here only need to be run once. They are moved out of
# the __init__ method to increase the speed of Linearizer creation.
self._form_permutation_matrices()
self._form_block_matrices()
self._form_coefficient_matrices()
self._setup_done = True
def _form_permutation_matrices(self):
"""Form the permutation matrices Pq and Pu."""
# Extract dimension variables
l, m, n, o, s, k = self._dims
# Compute permutation matrices
if n != 0:
self._Pq = permutation_matrix(self.q, Matrix([self.q_i, self.q_d]))
if l > 0:
self._Pqi = self._Pq[:, :-l]
self._Pqd = self._Pq[:, -l:]
else:
self._Pqi = self._Pq
self._Pqd = Matrix()
if o != 0:
self._Pu = permutation_matrix(self.u, Matrix([self.u_i, self.u_d]))
if m > 0:
self._Pui = self._Pu[:, :-m]
self._Pud = self._Pu[:, -m:]
else:
self._Pui = self._Pu
self._Pud = Matrix()
# Compute combination permutation matrix for computing A and B
P_col1 = Matrix([self._Pqi, zeros(o + k, n - l)])
P_col2 = Matrix([zeros(n, o - m), self._Pui, zeros(k, o - m)])
if P_col1:
if P_col2:
self.perm_mat = P_col1.row_join(P_col2)
else:
self.perm_mat = P_col1
else:
self.perm_mat = P_col2
def _form_coefficient_matrices(self):
"""Form the coefficient matrices C_0, C_1, and C_2."""
# Extract dimension variables
l, m, n, o, s, k = self._dims
# Build up the coefficient matrices C_0, C_1, and C_2
# If there are configuration constraints (l > 0), form C_0 as normal.
# If not, C_0 is I_(nxn). Note that this works even if n=0
if l > 0:
f_c_jac_q = self.f_c.jacobian(self.q)
self._C_0 = (eye(n) - self._Pqd *
self.linear_solver(f_c_jac_q*self._Pqd,
f_c_jac_q))*self._Pqi
else:
self._C_0 = eye(n)
# If there are motion constraints (m > 0), form C_1 and C_2 as normal.
# If not, C_1 is 0, and C_2 is I_(oxo). Note that this works even if
# o = 0.
if m > 0:
f_v_jac_u = self.f_v.jacobian(self.u)
temp = f_v_jac_u * self._Pud
if n != 0:
f_v_jac_q = self.f_v.jacobian(self.q)
self._C_1 = -self._Pud * self.linear_solver(temp, f_v_jac_q)
else:
self._C_1 = zeros(o, n)
self._C_2 = (eye(o) - self._Pud *
self.linear_solver(temp, f_v_jac_u))*self._Pui
else:
self._C_1 = zeros(o, n)
self._C_2 = eye(o)
def _form_block_matrices(self):
"""Form the block matrices for composing M, A, and B."""
# Extract dimension variables
l, m, n, o, s, k = self._dims
# Block Matrix Definitions. These are only defined if under certain
# conditions. If undefined, an empty matrix is used instead
if n != 0:
self._M_qq = self.f_0.jacobian(self._qd)
self._A_qq = -(self.f_0 + self.f_1).jacobian(self.q)
else:
self._M_qq = Matrix()
self._A_qq = Matrix()
if n != 0 and m != 0:
self._M_uqc = self.f_a.jacobian(self._qd_dup)
self._A_uqc = -self.f_a.jacobian(self.q)
else:
self._M_uqc = Matrix()
self._A_uqc = Matrix()
if n != 0 and o - m + k != 0:
self._M_uqd = self.f_3.jacobian(self._qd_dup)
self._A_uqd = -(self.f_2 + self.f_3 + self.f_4).jacobian(self.q)
else:
self._M_uqd = Matrix()
self._A_uqd = Matrix()
if o != 0 and m != 0:
self._M_uuc = self.f_a.jacobian(self._ud)
self._A_uuc = -self.f_a.jacobian(self.u)
else:
self._M_uuc = Matrix()
self._A_uuc = Matrix()
if o != 0 and o - m + k != 0:
self._M_uud = self.f_2.jacobian(self._ud)
self._A_uud = -(self.f_2 + self.f_3).jacobian(self.u)
else:
self._M_uud = Matrix()
self._A_uud = Matrix()
if o != 0 and n != 0:
self._A_qu = -self.f_1.jacobian(self.u)
else:
self._A_qu = Matrix()
if k != 0 and o - m + k != 0:
self._M_uld = self.f_4.jacobian(self.lams)
else:
self._M_uld = Matrix()
if s != 0 and o - m + k != 0:
self._B_u = -self.f_3.jacobian(self.r)
else:
self._B_u = Matrix()
def linearize(self, op_point=None, A_and_B=False, simplify=False):
"""Linearize the system about the operating point. Note that
q_op, u_op, qd_op, ud_op must satisfy the equations of motion.
These may be either symbolic or numeric.
Parameters
==========
op_point : dict or iterable of dicts, optional
Dictionary or iterable of dictionaries containing the operating
point conditions for all or a subset of the generalized
coordinates, generalized speeds, and time derivatives of the
generalized speeds. These will be substituted into the linearized
system before the linearization is complete. Leave set to ``None``
if you want the operating point to be an arbitrary set of symbols.
Note that any reduction in symbols (whether substituted for numbers
or expressions with a common parameter) will result in faster
runtime.
A_and_B : bool, optional
If A_and_B=False (default), (M, A, B) is returned and of
A_and_B=True, (A, B) is returned. See below.
simplify : bool, optional
Determines if returned values are simplified before return.
For large expressions this may be time consuming. Default is False.
Returns
=======
M, A, B : Matrices, ``A_and_B=False``
Matrices from the implicit form:
``[M]*[q', u']^T = [A]*[q_ind, u_ind]^T + [B]*r``
A, B : Matrices, ``A_and_B=True``
Matrices from the explicit form:
``[q_ind', u_ind']^T = [A]*[q_ind, u_ind]^T + [B]*r``
Notes
=====
Note that the process of solving with A_and_B=True is computationally
intensive if there are many symbolic parameters. For this reason, it
may be more desirable to use the default A_and_B=False, returning M, A,
and B. More values may then be substituted in to these matrices later
on. The state space form can then be found as A = P.T*M.LUsolve(A), B =
P.T*M.LUsolve(B), where P = Linearizer.perm_mat.
"""
# Run the setup if needed:
if not self._setup_done:
self._setup()
# Compose dict of operating conditions
if isinstance(op_point, dict):
op_point_dict = op_point
elif isinstance(op_point, Iterable):
op_point_dict = {}
for op in op_point:
op_point_dict.update(op)
else:
op_point_dict = {}
# Extract dimension variables
l, m, n, o, s, k = self._dims
# Rename terms to shorten expressions
M_qq = self._M_qq
M_uqc = self._M_uqc
M_uqd = self._M_uqd
M_uuc = self._M_uuc
M_uud = self._M_uud
M_uld = self._M_uld
A_qq = self._A_qq
A_uqc = self._A_uqc
A_uqd = self._A_uqd
A_qu = self._A_qu
A_uuc = self._A_uuc
A_uud = self._A_uud
B_u = self._B_u
C_0 = self._C_0
C_1 = self._C_1
C_2 = self._C_2
# Build up Mass Matrix
# |M_qq 0_nxo 0_nxk|
# M = |M_uqc M_uuc 0_mxk|
# |M_uqd M_uud M_uld|
if o != 0:
col2 = Matrix([zeros(n, o), M_uuc, M_uud])
if k != 0:
col3 = Matrix([zeros(n + m, k), M_uld])
if n != 0:
col1 = Matrix([M_qq, M_uqc, M_uqd])
if o != 0 and k != 0:
M = col1.row_join(col2).row_join(col3)
elif o != 0:
M = col1.row_join(col2)
else:
M = col1
elif k != 0:
M = col2.row_join(col3)
else:
M = col2
M_eq = msubs(M, op_point_dict)
# Build up state coefficient matrix A
# |(A_qq + A_qu*C_1)*C_0 A_qu*C_2|
# A = |(A_uqc + A_uuc*C_1)*C_0 A_uuc*C_2|
# |(A_uqd + A_uud*C_1)*C_0 A_uud*C_2|
# Col 1 is only defined if n != 0
if n != 0:
r1c1 = A_qq
if o != 0:
r1c1 += (A_qu * C_1)
r1c1 = r1c1 * C_0
if m != 0:
r2c1 = A_uqc
if o != 0:
r2c1 += (A_uuc * C_1)
r2c1 = r2c1 * C_0
else:
r2c1 = Matrix()
if o - m + k != 0:
r3c1 = A_uqd
if o != 0:
r3c1 += (A_uud * C_1)
r3c1 = r3c1 * C_0
else:
r3c1 = Matrix()
col1 = Matrix([r1c1, r2c1, r3c1])
else:
col1 = Matrix()
# Col 2 is only defined if o != 0
if o != 0:
if n != 0:
r1c2 = A_qu * C_2
else:
r1c2 = Matrix()
if m != 0:
r2c2 = A_uuc * C_2
else:
r2c2 = Matrix()
if o - m + k != 0:
r3c2 = A_uud * C_2
else:
r3c2 = Matrix()
col2 = Matrix([r1c2, r2c2, r3c2])
else:
col2 = Matrix()
if col1:
if col2:
Amat = col1.row_join(col2)
else:
Amat = col1
else:
Amat = col2
Amat_eq = msubs(Amat, op_point_dict)
# Build up the B matrix if there are forcing variables
# |0_(n + m)xs|
# B = |B_u |
if s != 0 and o - m + k != 0:
Bmat = zeros(n + m, s).col_join(B_u)
Bmat_eq = msubs(Bmat, op_point_dict)
else:
Bmat_eq = Matrix()
# kwarg A_and_B indicates to return A, B for forming the equation
# dx = [A]x + [B]r, where x = [q_indnd, u_indnd]^T,
if A_and_B:
A_cont = self.perm_mat.T * self.linear_solver(M_eq, Amat_eq)
if Bmat_eq:
B_cont = self.perm_mat.T * self.linear_solver(M_eq, Bmat_eq)
else:
# Bmat = Matrix([]), so no need to sub
B_cont = Bmat_eq
if simplify:
A_cont.simplify()
B_cont.simplify()
return A_cont, B_cont
# Otherwise return M, A, B for forming the equation
# [M]dx = [A]x + [B]r, where x = [q, u]^T
else:
if simplify:
M_eq.simplify()
Amat_eq.simplify()
Bmat_eq.simplify()
return M_eq, Amat_eq, Bmat_eq
def permutation_matrix(orig_vec, per_vec):
"""Compute the permutation matrix to change order of
orig_vec into order of per_vec.
Parameters
==========
orig_vec : array_like
Symbols in original ordering.
per_vec : array_like
Symbols in new ordering.
Returns
=======
p_matrix : Matrix
Permutation matrix such that orig_vec == (p_matrix * per_vec).
"""
if not isinstance(orig_vec, (list, tuple)):
orig_vec = flatten(orig_vec)
if not isinstance(per_vec, (list, tuple)):
per_vec = flatten(per_vec)
if set(orig_vec) != set(per_vec):
raise ValueError("orig_vec and per_vec must be the same length, "
"and contain the same symbols.")
ind_list = [orig_vec.index(i) for i in per_vec]
p_matrix = zeros(len(orig_vec))
for i, j in enumerate(ind_list):
p_matrix[i, j] = 1
return p_matrix
PK ]ZZZaV B sympy/physics/mechanics/loads.pyfrom abc import ABC
from collections import namedtuple
from sympy.physics.mechanics.body_base import BodyBase
from sympy.physics.vector import Vector, ReferenceFrame, Point
__all__ = ['LoadBase', 'Force', 'Torque']
class LoadBase(ABC, namedtuple('LoadBase', ['location', 'vector'])):
"""Abstract base class for the various loading types."""
def __add__(self, other):
raise TypeError(f"unsupported operand type(s) for +: "
f"'{self.__class__.__name__}' and "
f"'{other.__class__.__name__}'")
def __mul__(self, other):
raise TypeError(f"unsupported operand type(s) for *: "
f"'{self.__class__.__name__}' and "
f"'{other.__class__.__name__}'")
__radd__ = __add__
__rmul__ = __mul__
class Force(LoadBase):
"""Force acting upon a point.
Explanation
===========
A force is a vector that is bound to a line of action. This class stores
both a point, which lies on the line of action, and the vector. A tuple can
also be used, with the location as the first entry and the vector as second
entry.
Examples
========
A force of magnitude 2 along N.x acting on a point Po can be created as
follows:
>>> from sympy.physics.mechanics import Point, ReferenceFrame, Force
>>> N = ReferenceFrame('N')
>>> Po = Point('Po')
>>> Force(Po, 2 * N.x)
(Po, 2*N.x)
If a body is supplied, then the center of mass of that body is used.
>>> from sympy.physics.mechanics import Particle
>>> P = Particle('P', point=Po)
>>> Force(P, 2 * N.x)
(Po, 2*N.x)
"""
def __new__(cls, point, force):
if isinstance(point, BodyBase):
point = point.masscenter
if not isinstance(point, Point):
raise TypeError('Force location should be a Point.')
if not isinstance(force, Vector):
raise TypeError('Force vector should be a Vector.')
return super().__new__(cls, point, force)
def __repr__(self):
return (f'{self.__class__.__name__}(point={self.point}, '
f'force={self.force})')
@property
def point(self):
return self.location
@property
def force(self):
return self.vector
class Torque(LoadBase):
"""Torque acting upon a frame.
Explanation
===========
A torque is a free vector that is acting on a reference frame, which is
associated with a rigid body. This class stores both the frame and the
vector. A tuple can also be used, with the location as the first item and
the vector as second item.
Examples
========
A torque of magnitude 2 about N.x acting on a frame N can be created as
follows:
>>> from sympy.physics.mechanics import ReferenceFrame, Torque
>>> N = ReferenceFrame('N')
>>> Torque(N, 2 * N.x)
(N, 2*N.x)
If a body is supplied, then the frame fixed to that body is used.
>>> from sympy.physics.mechanics import RigidBody
>>> rb = RigidBody('rb', frame=N)
>>> Torque(rb, 2 * N.x)
(N, 2*N.x)
"""
def __new__(cls, frame, torque):
if isinstance(frame, BodyBase):
frame = frame.frame
if not isinstance(frame, ReferenceFrame):
raise TypeError('Torque location should be a ReferenceFrame.')
if not isinstance(torque, Vector):
raise TypeError('Torque vector should be a Vector.')
return super().__new__(cls, frame, torque)
def __repr__(self):
return (f'{self.__class__.__name__}(frame={self.frame}, '
f'torque={self.torque})')
@property
def frame(self):
return self.location
@property
def torque(self):
return self.vector
def gravity(acceleration, *bodies):
"""
Returns a list of gravity forces given the acceleration
due to gravity and any number of particles or rigidbodies.
Example
=======
>>> from sympy.physics.mechanics import ReferenceFrame, Particle, RigidBody
>>> from sympy.physics.mechanics.loads import gravity
>>> from sympy import symbols
>>> N = ReferenceFrame('N')
>>> g = symbols('g')
>>> P = Particle('P')
>>> B = RigidBody('B')
>>> gravity(g*N.y, P, B)
[(P_masscenter, P_mass*g*N.y),
(B_masscenter, B_mass*g*N.y)]
"""
gravity_force = []
for body in bodies:
if not isinstance(body, BodyBase):
raise TypeError(f'{type(body)} is not a body type')
gravity_force.append(Force(body.masscenter, body.mass * acceleration))
return gravity_force
def _parse_load(load):
"""Helper function to parse loads and convert tuples to load objects."""
if isinstance(load, LoadBase):
return load
elif isinstance(load, tuple):
if len(load) != 2:
raise ValueError(f'Load {load} should have a length of 2.')
if isinstance(load[0], Point):
return Force(load[0], load[1])
elif isinstance(load[0], ReferenceFrame):
return Torque(load[0], load[1])
else:
raise ValueError(f'Load not recognized. The load location {load[0]}'
f' should either be a Point or a ReferenceFrame.')
raise TypeError(f'Load type {type(load)} not recognized as a load. It '
f'should be a Force, Torque or tuple.')
PK ]ZZZ�2A�� � ! sympy/physics/mechanics/method.pyfrom abc import ABC, abstractmethod
class _Methods(ABC):
"""Abstract Base Class for all methods."""
@abstractmethod
def q(self):
pass
@abstractmethod
def u(self):
pass
@abstractmethod
def bodies(self):
pass
@abstractmethod
def loads(self):
pass
@abstractmethod
def mass_matrix(self):
pass
@abstractmethod
def forcing(self):
pass
@abstractmethod
def mass_matrix_full(self):
pass
@abstractmethod
def forcing_full(self):
pass
def _form_eoms(self):
raise NotImplementedError("Subclasses must implement this.")
PK ]ZZZ�@�? ? ! sympy/physics/mechanics/models.py#!/usr/bin/env python
"""This module contains some sample symbolic models used for testing and
examples."""
# Internal imports
from sympy.core import backend as sm
import sympy.physics.mechanics as me
def multi_mass_spring_damper(n=1, apply_gravity=False,
apply_external_forces=False):
r"""Returns a system containing the symbolic equations of motion and
associated variables for a simple multi-degree of freedom point mass,
spring, damper system with optional gravitational and external
specified forces. For example, a two mass system under the influence of
gravity and external forces looks like:
::
----------------
| | | | g
\ | | | V
k0 / --- c0 |
| | | x0, v0
--------- V
| m0 | -----
--------- |
| | | |
\ v | | |
k1 / f0 --- c1 |
| | | x1, v1
--------- V
| m1 | -----
---------
| f1
V
Parameters
==========
n : integer
The number of masses in the serial chain.
apply_gravity : boolean
If true, gravity will be applied to each mass.
apply_external_forces : boolean
If true, a time varying external force will be applied to each mass.
Returns
=======
kane : sympy.physics.mechanics.kane.KanesMethod
A KanesMethod object.
"""
mass = sm.symbols('m:{}'.format(n))
stiffness = sm.symbols('k:{}'.format(n))
damping = sm.symbols('c:{}'.format(n))
acceleration_due_to_gravity = sm.symbols('g')
coordinates = me.dynamicsymbols('x:{}'.format(n))
speeds = me.dynamicsymbols('v:{}'.format(n))
specifieds = me.dynamicsymbols('f:{}'.format(n))
ceiling = me.ReferenceFrame('N')
origin = me.Point('origin')
origin.set_vel(ceiling, 0)
points = [origin]
kinematic_equations = []
particles = []
forces = []
for i in range(n):
center = points[-1].locatenew('center{}'.format(i),
coordinates[i] * ceiling.x)
center.set_vel(ceiling, points[-1].vel(ceiling) +
speeds[i] * ceiling.x)
points.append(center)
block = me.Particle('block{}'.format(i), center, mass[i])
kinematic_equations.append(speeds[i] - coordinates[i].diff())
total_force = (-stiffness[i] * coordinates[i] -
damping[i] * speeds[i])
try:
total_force += (stiffness[i + 1] * coordinates[i + 1] +
damping[i + 1] * speeds[i + 1])
except IndexError: # no force from below on last mass
pass
if apply_gravity:
total_force += mass[i] * acceleration_due_to_gravity
if apply_external_forces:
total_force += specifieds[i]
forces.append((center, total_force * ceiling.x))
particles.append(block)
kane = me.KanesMethod(ceiling, q_ind=coordinates, u_ind=speeds,
kd_eqs=kinematic_equations)
kane.kanes_equations(particles, forces)
return kane
def n_link_pendulum_on_cart(n=1, cart_force=True, joint_torques=False):
r"""Returns the system containing the symbolic first order equations of
motion for a 2D n-link pendulum on a sliding cart under the influence of
gravity.
::
|
o y v
\ 0 ^ g
\ |
--\-|----
| \| |
F-> | o --|---> x
| |
---------
o o
Parameters
==========
n : integer
The number of links in the pendulum.
cart_force : boolean, default=True
If true an external specified lateral force is applied to the cart.
joint_torques : boolean, default=False
If true joint torques will be added as specified inputs at each
joint.
Returns
=======
kane : sympy.physics.mechanics.kane.KanesMethod
A KanesMethod object.
Notes
=====
The degrees of freedom of the system are n + 1, i.e. one for each
pendulum link and one for the lateral motion of the cart.
M x' = F, where x = [u0, ..., un+1, q0, ..., qn+1]
The joint angles are all defined relative to the ground where the x axis
defines the ground line and the y axis points up. The joint torques are
applied between each adjacent link and the between the cart and the
lower link where a positive torque corresponds to positive angle.
"""
if n <= 0:
raise ValueError('The number of links must be a positive integer.')
q = me.dynamicsymbols('q:{}'.format(n + 1))
u = me.dynamicsymbols('u:{}'.format(n + 1))
if joint_torques is True:
T = me.dynamicsymbols('T1:{}'.format(n + 1))
m = sm.symbols('m:{}'.format(n + 1))
l = sm.symbols('l:{}'.format(n))
g, t = sm.symbols('g t')
I = me.ReferenceFrame('I')
O = me.Point('O')
O.set_vel(I, 0)
P0 = me.Point('P0')
P0.set_pos(O, q[0] * I.x)
P0.set_vel(I, u[0] * I.x)
Pa0 = me.Particle('Pa0', P0, m[0])
frames = [I]
points = [P0]
particles = [Pa0]
forces = [(P0, -m[0] * g * I.y)]
kindiffs = [q[0].diff(t) - u[0]]
if cart_force is True or joint_torques is True:
specified = []
else:
specified = None
for i in range(n):
Bi = I.orientnew('B{}'.format(i), 'Axis', [q[i + 1], I.z])
Bi.set_ang_vel(I, u[i + 1] * I.z)
frames.append(Bi)
Pi = points[-1].locatenew('P{}'.format(i + 1), l[i] * Bi.y)
Pi.v2pt_theory(points[-1], I, Bi)
points.append(Pi)
Pai = me.Particle('Pa' + str(i + 1), Pi, m[i + 1])
particles.append(Pai)
forces.append((Pi, -m[i + 1] * g * I.y))
if joint_torques is True:
specified.append(T[i])
if i == 0:
forces.append((I, -T[i] * I.z))
if i == n - 1:
forces.append((Bi, T[i] * I.z))
else:
forces.append((Bi, T[i] * I.z - T[i + 1] * I.z))
kindiffs.append(q[i + 1].diff(t) - u[i + 1])
if cart_force is True:
F = me.dynamicsymbols('F')
forces.append((P0, F * I.x))
specified.append(F)
kane = me.KanesMethod(I, q_ind=q, u_ind=u, kd_eqs=kindiffs)
kane.kanes_equations(particles, forces)
return kane
PK ]ZZZSA�Wa a # sympy/physics/mechanics/particle.pyfrom sympy import S
from sympy.physics.vector import cross, dot
from sympy.physics.mechanics.body_base import BodyBase
from sympy.physics.mechanics.inertia import inertia_of_point_mass
from sympy.utilities.exceptions import sympy_deprecation_warning
__all__ = ['Particle']
class Particle(BodyBase):
"""A particle.
Explanation
===========
Particles have a non-zero mass and lack spatial extension; they take up no
space.
Values need to be supplied on initialization, but can be changed later.
Parameters
==========
name : str
Name of particle
point : Point
A physics/mechanics Point which represents the position, velocity, and
acceleration of this Particle
mass : Sympifyable
A SymPy expression representing the Particle's mass
potential_energy : Sympifyable
The potential energy of the Particle.
Examples
========
>>> from sympy.physics.mechanics import Particle, Point
>>> from sympy import Symbol
>>> po = Point('po')
>>> m = Symbol('m')
>>> pa = Particle('pa', po, m)
>>> # Or you could change these later
>>> pa.mass = m
>>> pa.point = po
"""
point = BodyBase.masscenter
def __init__(self, name, point=None, mass=None):
super().__init__(name, point, mass)
def linear_momentum(self, frame):
"""Linear momentum of the particle.
Explanation
===========
The linear momentum L, of a particle P, with respect to frame N is
given by:
L = m * v
where m is the mass of the particle, and v is the velocity of the
particle in the frame N.
Parameters
==========
frame : ReferenceFrame
The frame in which linear momentum is desired.
Examples
========
>>> from sympy.physics.mechanics import Particle, Point, ReferenceFrame
>>> from sympy.physics.mechanics import dynamicsymbols
>>> from sympy.physics.vector import init_vprinting
>>> init_vprinting(pretty_print=False)
>>> m, v = dynamicsymbols('m v')
>>> N = ReferenceFrame('N')
>>> P = Point('P')
>>> A = Particle('A', P, m)
>>> P.set_vel(N, v * N.x)
>>> A.linear_momentum(N)
m*v*N.x
"""
return self.mass * self.point.vel(frame)
def angular_momentum(self, point, frame):
"""Angular momentum of the particle about the point.
Explanation
===========
The angular momentum H, about some point O of a particle, P, is given
by:
``H = cross(r, m * v)``
where r is the position vector from point O to the particle P, m is
the mass of the particle, and v is the velocity of the particle in
the inertial frame, N.
Parameters
==========
point : Point
The point about which angular momentum of the particle is desired.
frame : ReferenceFrame
The frame in which angular momentum is desired.
Examples
========
>>> from sympy.physics.mechanics import Particle, Point, ReferenceFrame
>>> from sympy.physics.mechanics import dynamicsymbols
>>> from sympy.physics.vector import init_vprinting
>>> init_vprinting(pretty_print=False)
>>> m, v, r = dynamicsymbols('m v r')
>>> N = ReferenceFrame('N')
>>> O = Point('O')
>>> A = O.locatenew('A', r * N.x)
>>> P = Particle('P', A, m)
>>> P.point.set_vel(N, v * N.y)
>>> P.angular_momentum(O, N)
m*r*v*N.z
"""
return cross(self.point.pos_from(point),
self.mass * self.point.vel(frame))
def kinetic_energy(self, frame):
"""Kinetic energy of the particle.
Explanation
===========
The kinetic energy, T, of a particle, P, is given by:
``T = 1/2 (dot(m * v, v))``
where m is the mass of particle P, and v is the velocity of the
particle in the supplied ReferenceFrame.
Parameters
==========
frame : ReferenceFrame
The Particle's velocity is typically defined with respect to
an inertial frame but any relevant frame in which the velocity is
known can be supplied.
Examples
========
>>> from sympy.physics.mechanics import Particle, Point, ReferenceFrame
>>> from sympy import symbols
>>> m, v, r = symbols('m v r')
>>> N = ReferenceFrame('N')
>>> O = Point('O')
>>> P = Particle('P', O, m)
>>> P.point.set_vel(N, v * N.y)
>>> P.kinetic_energy(N)
m*v**2/2
"""
return S.Half * self.mass * dot(self.point.vel(frame),
self.point.vel(frame))
def set_potential_energy(self, scalar):
sympy_deprecation_warning(
"""
The sympy.physics.mechanics.Particle.set_potential_energy()
method is deprecated. Instead use
P.potential_energy = scalar
""",
deprecated_since_version="1.5",
active_deprecations_target="deprecated-set-potential-energy",
)
self.potential_energy = scalar
def parallel_axis(self, point, frame):
"""Returns an inertia dyadic of the particle with respect to another
point and frame.
Parameters
==========
point : sympy.physics.vector.Point
The point to express the inertia dyadic about.
frame : sympy.physics.vector.ReferenceFrame
The reference frame used to construct the dyadic.
Returns
=======
inertia : sympy.physics.vector.Dyadic
The inertia dyadic of the particle expressed about the provided
point and frame.
"""
return inertia_of_point_mass(self.mass, self.point.pos_from(point),
frame)
PK ]ZZZ6�ꈾg �g " sympy/physics/mechanics/pathway.py"""Implementations of pathways for use by actuators."""
from abc import ABC, abstractmethod
from sympy.core.singleton import S
from sympy.physics.mechanics.loads import Force
from sympy.physics.mechanics.wrapping_geometry import WrappingGeometryBase
from sympy.physics.vector import Point, dynamicsymbols
__all__ = ['PathwayBase', 'LinearPathway', 'ObstacleSetPathway',
'WrappingPathway']
class PathwayBase(ABC):
"""Abstract base class for all pathway classes to inherit from.
Notes
=====
Instances of this class cannot be directly instantiated by users. However,
it can be used to created custom pathway types through subclassing.
"""
def __init__(self, *attachments):
"""Initializer for ``PathwayBase``."""
self.attachments = attachments
@property
def attachments(self):
"""The pair of points defining a pathway's ends."""
return self._attachments
@attachments.setter
def attachments(self, attachments):
if hasattr(self, '_attachments'):
msg = (
f'Can\'t set attribute `attachments` to {repr(attachments)} '
f'as it is immutable.'
)
raise AttributeError(msg)
if len(attachments) != 2:
msg = (
f'Value {repr(attachments)} passed to `attachments` was an '
f'iterable of length {len(attachments)}, must be an iterable '
f'of length 2.'
)
raise ValueError(msg)
for i, point in enumerate(attachments):
if not isinstance(point, Point):
msg = (
f'Value {repr(point)} passed to `attachments` at index '
f'{i} was of type {type(point)}, must be {Point}.'
)
raise TypeError(msg)
self._attachments = tuple(attachments)
@property
@abstractmethod
def length(self):
"""An expression representing the pathway's length."""
pass
@property
@abstractmethod
def extension_velocity(self):
"""An expression representing the pathway's extension velocity."""
pass
@abstractmethod
def to_loads(self, force):
"""Loads required by the equations of motion method classes.
Explanation
===========
``KanesMethod`` requires a list of ``Point``-``Vector`` tuples to be
passed to the ``loads`` parameters of its ``kanes_equations`` method
when constructing the equations of motion. This method acts as a
utility to produce the correctly-structred pairs of points and vectors
required so that these can be easily concatenated with other items in
the list of loads and passed to ``KanesMethod.kanes_equations``. These
loads are also in the correct form to also be passed to the other
equations of motion method classes, e.g. ``LagrangesMethod``.
"""
pass
def __repr__(self):
"""Default representation of a pathway."""
attachments = ', '.join(str(a) for a in self.attachments)
return f'{self.__class__.__name__}({attachments})'
class LinearPathway(PathwayBase):
"""Linear pathway between a pair of attachment points.
Explanation
===========
A linear pathway forms a straight-line segment between two points and is
the simplest pathway that can be formed. It will not interact with any
other objects in the system, i.e. a ``LinearPathway`` will intersect other
objects to ensure that the path between its two ends (its attachments) is
the shortest possible.
A linear pathway is made up of two points that can move relative to each
other, and a pair of equal and opposite forces acting on the points. If the
positive time-varying Euclidean distance between the two points is defined,
then the "extension velocity" is the time derivative of this distance. The
extension velocity is positive when the two points are moving away from
each other and negative when moving closer to each other. The direction for
the force acting on either point is determined by constructing a unit
vector directed from the other point to this point. This establishes a sign
convention such that a positive force magnitude tends to push the points
apart. The following diagram shows the positive force sense and the
distance between the points::
P Q
o<--- F --->o
| |
|<--l(t)--->|
Examples
========
>>> from sympy.physics.mechanics import LinearPathway
To construct a pathway, two points are required to be passed to the
``attachments`` parameter as a ``tuple``.
>>> from sympy.physics.mechanics import Point
>>> pA, pB = Point('pA'), Point('pB')
>>> linear_pathway = LinearPathway(pA, pB)
>>> linear_pathway
LinearPathway(pA, pB)
The pathway created above isn't very interesting without the positions and
velocities of its attachment points being described. Without this its not
possible to describe how the pathway moves, i.e. its length or its
extension velocity.
>>> from sympy.physics.mechanics import ReferenceFrame
>>> from sympy.physics.vector import dynamicsymbols
>>> N = ReferenceFrame('N')
>>> q = dynamicsymbols('q')
>>> pB.set_pos(pA, q*N.x)
>>> pB.pos_from(pA)
q(t)*N.x
A pathway's length can be accessed via its ``length`` attribute.
>>> linear_pathway.length
sqrt(q(t)**2)
Note how what appears to be an overly-complex expression is returned. This
is actually required as it ensures that a pathway's length is always
positive.
A pathway's extension velocity can be accessed similarly via its
``extension_velocity`` attribute.
>>> linear_pathway.extension_velocity
sqrt(q(t)**2)*Derivative(q(t), t)/q(t)
Parameters
==========
attachments : tuple[Point, Point]
Pair of ``Point`` objects between which the linear pathway spans.
Constructor expects two points to be passed, e.g.
``LinearPathway(Point('pA'), Point('pB'))``. More or fewer points will
cause an error to be thrown.
"""
def __init__(self, *attachments):
"""Initializer for ``LinearPathway``.
Parameters
==========
attachments : Point
Pair of ``Point`` objects between which the linear pathway spans.
Constructor expects two points to be passed, e.g.
``LinearPathway(Point('pA'), Point('pB'))``. More or fewer points
will cause an error to be thrown.
"""
super().__init__(*attachments)
@property
def length(self):
"""Exact analytical expression for the pathway's length."""
return _point_pair_length(*self.attachments)
@property
def extension_velocity(self):
"""Exact analytical expression for the pathway's extension velocity."""
return _point_pair_extension_velocity(*self.attachments)
def to_loads(self, force):
"""Loads required by the equations of motion method classes.
Explanation
===========
``KanesMethod`` requires a list of ``Point``-``Vector`` tuples to be
passed to the ``loads`` parameters of its ``kanes_equations`` method
when constructing the equations of motion. This method acts as a
utility to produce the correctly-structred pairs of points and vectors
required so that these can be easily concatenated with other items in
the list of loads and passed to ``KanesMethod.kanes_equations``. These
loads are also in the correct form to also be passed to the other
equations of motion method classes, e.g. ``LagrangesMethod``.
Examples
========
The below example shows how to generate the loads produced in a linear
actuator that produces an expansile force ``F``. First, create a linear
actuator between two points separated by the coordinate ``q`` in the
``x`` direction of the global frame ``N``.
>>> from sympy.physics.mechanics import (LinearPathway, Point,
... ReferenceFrame)
>>> from sympy.physics.vector import dynamicsymbols
>>> q = dynamicsymbols('q')
>>> N = ReferenceFrame('N')
>>> pA, pB = Point('pA'), Point('pB')
>>> pB.set_pos(pA, q*N.x)
>>> linear_pathway = LinearPathway(pA, pB)
Now create a symbol ``F`` to describe the magnitude of the (expansile)
force that will be produced along the pathway. The list of loads that
``KanesMethod`` requires can be produced by calling the pathway's
``to_loads`` method with ``F`` passed as the only argument.
>>> from sympy import symbols
>>> F = symbols('F')
>>> linear_pathway.to_loads(F)
[(pA, - F*q(t)/sqrt(q(t)**2)*N.x), (pB, F*q(t)/sqrt(q(t)**2)*N.x)]
Parameters
==========
force : Expr
Magnitude of the force acting along the length of the pathway. As
per the sign conventions for the pathway length, pathway extension
velocity, and pair of point forces, if this ``Expr`` is positive
then the force will act to push the pair of points away from one
another (it is expansile).
"""
relative_position = _point_pair_relative_position(*self.attachments)
loads = [
Force(self.attachments[0], -force*relative_position/self.length),
Force(self.attachments[-1], force*relative_position/self.length),
]
return loads
class ObstacleSetPathway(PathwayBase):
"""Obstacle-set pathway between a set of attachment points.
Explanation
===========
An obstacle-set pathway forms a series of straight-line segment between
pairs of consecutive points in a set of points. It is similiar to multiple
linear pathways joined end-to-end. It will not interact with any other
objects in the system, i.e. an ``ObstacleSetPathway`` will intersect other
objects to ensure that the path between its pairs of points (its
attachments) is the shortest possible.
Examples
========
To construct an obstacle-set pathway, three or more points are required to
be passed to the ``attachments`` parameter as a ``tuple``.
>>> from sympy.physics.mechanics import ObstacleSetPathway, Point
>>> pA, pB, pC, pD = Point('pA'), Point('pB'), Point('pC'), Point('pD')
>>> obstacle_set_pathway = ObstacleSetPathway(pA, pB, pC, pD)
>>> obstacle_set_pathway
ObstacleSetPathway(pA, pB, pC, pD)
The pathway created above isn't very interesting without the positions and
velocities of its attachment points being described. Without this its not
possible to describe how the pathway moves, i.e. its length or its
extension velocity.
>>> from sympy import cos, sin
>>> from sympy.physics.mechanics import ReferenceFrame
>>> from sympy.physics.vector import dynamicsymbols
>>> N = ReferenceFrame('N')
>>> q = dynamicsymbols('q')
>>> pO = Point('pO')
>>> pA.set_pos(pO, N.y)
>>> pB.set_pos(pO, -N.x)
>>> pC.set_pos(pA, cos(q) * N.x - (sin(q) + 1) * N.y)
>>> pD.set_pos(pA, sin(q) * N.x + (cos(q) - 1) * N.y)
>>> pB.pos_from(pA)
- N.x - N.y
>>> pC.pos_from(pA)
cos(q(t))*N.x + (-sin(q(t)) - 1)*N.y
>>> pD.pos_from(pA)
sin(q(t))*N.x + (cos(q(t)) - 1)*N.y
A pathway's length can be accessed via its ``length`` attribute.
>>> obstacle_set_pathway.length.simplify()
sqrt(2)*(sqrt(cos(q(t)) + 1) + 2)
A pathway's extension velocity can be accessed similarly via its
``extension_velocity`` attribute.
>>> obstacle_set_pathway.extension_velocity.simplify()
-sqrt(2)*sin(q(t))*Derivative(q(t), t)/(2*sqrt(cos(q(t)) + 1))
Parameters
==========
attachments : tuple[Point, Point]
The set of ``Point`` objects that define the segmented obstacle-set
pathway.
"""
def __init__(self, *attachments):
"""Initializer for ``ObstacleSetPathway``.
Parameters
==========
attachments : tuple[Point, ...]
The set of ``Point`` objects that define the segmented obstacle-set
pathway.
"""
super().__init__(*attachments)
@property
def attachments(self):
"""The set of points defining a pathway's segmented path."""
return self._attachments
@attachments.setter
def attachments(self, attachments):
if hasattr(self, '_attachments'):
msg = (
f'Can\'t set attribute `attachments` to {repr(attachments)} '
f'as it is immutable.'
)
raise AttributeError(msg)
if len(attachments) <= 2:
msg = (
f'Value {repr(attachments)} passed to `attachments` was an '
f'iterable of length {len(attachments)}, must be an iterable '
f'of length 3 or greater.'
)
raise ValueError(msg)
for i, point in enumerate(attachments):
if not isinstance(point, Point):
msg = (
f'Value {repr(point)} passed to `attachments` at index '
f'{i} was of type {type(point)}, must be {Point}.'
)
raise TypeError(msg)
self._attachments = tuple(attachments)
@property
def length(self):
"""Exact analytical expression for the pathway's length."""
length = S.Zero
attachment_pairs = zip(self.attachments[:-1], self.attachments[1:])
for attachment_pair in attachment_pairs:
length += _point_pair_length(*attachment_pair)
return length
@property
def extension_velocity(self):
"""Exact analytical expression for the pathway's extension velocity."""
extension_velocity = S.Zero
attachment_pairs = zip(self.attachments[:-1], self.attachments[1:])
for attachment_pair in attachment_pairs:
extension_velocity += _point_pair_extension_velocity(*attachment_pair)
return extension_velocity
def to_loads(self, force):
"""Loads required by the equations of motion method classes.
Explanation
===========
``KanesMethod`` requires a list of ``Point``-``Vector`` tuples to be
passed to the ``loads`` parameters of its ``kanes_equations`` method
when constructing the equations of motion. This method acts as a
utility to produce the correctly-structred pairs of points and vectors
required so that these can be easily concatenated with other items in
the list of loads and passed to ``KanesMethod.kanes_equations``. These
loads are also in the correct form to also be passed to the other
equations of motion method classes, e.g. ``LagrangesMethod``.
Examples
========
The below example shows how to generate the loads produced in an
actuator that follows an obstacle-set pathway between four points and
produces an expansile force ``F``. First, create a pair of reference
frames, ``A`` and ``B``, in which the four points ``pA``, ``pB``,
``pC``, and ``pD`` will be located. The first two points in frame ``A``
and the second two in frame ``B``. Frame ``B`` will also be oriented
such that it relates to ``A`` via a rotation of ``q`` about an axis
``N.z`` in a global frame (``N.z``, ``A.z``, and ``B.z`` are parallel).
>>> from sympy.physics.mechanics import (ObstacleSetPathway, Point,
... ReferenceFrame)
>>> from sympy.physics.vector import dynamicsymbols
>>> q = dynamicsymbols('q')
>>> N = ReferenceFrame('N')
>>> N = ReferenceFrame('N')
>>> A = N.orientnew('A', 'axis', (0, N.x))
>>> B = A.orientnew('B', 'axis', (q, N.z))
>>> pO = Point('pO')
>>> pA, pB, pC, pD = Point('pA'), Point('pB'), Point('pC'), Point('pD')
>>> pA.set_pos(pO, A.x)
>>> pB.set_pos(pO, -A.y)
>>> pC.set_pos(pO, B.y)
>>> pD.set_pos(pO, B.x)
>>> obstacle_set_pathway = ObstacleSetPathway(pA, pB, pC, pD)
Now create a symbol ``F`` to describe the magnitude of the (expansile)
force that will be produced along the pathway. The list of loads that
``KanesMethod`` requires can be produced by calling the pathway's
``to_loads`` method with ``F`` passed as the only argument.
>>> from sympy import Symbol
>>> F = Symbol('F')
>>> obstacle_set_pathway.to_loads(F)
[(pA, sqrt(2)*F/2*A.x + sqrt(2)*F/2*A.y),
(pB, - sqrt(2)*F/2*A.x - sqrt(2)*F/2*A.y),
(pB, - F/sqrt(2*cos(q(t)) + 2)*A.y - F/sqrt(2*cos(q(t)) + 2)*B.y),
(pC, F/sqrt(2*cos(q(t)) + 2)*A.y + F/sqrt(2*cos(q(t)) + 2)*B.y),
(pC, - sqrt(2)*F/2*B.x + sqrt(2)*F/2*B.y),
(pD, sqrt(2)*F/2*B.x - sqrt(2)*F/2*B.y)]
Parameters
==========
force : Expr
The force acting along the length of the pathway. It is assumed
that this ``Expr`` represents an expansile force.
"""
loads = []
attachment_pairs = zip(self.attachments[:-1], self.attachments[1:])
for attachment_pair in attachment_pairs:
relative_position = _point_pair_relative_position(*attachment_pair)
length = _point_pair_length(*attachment_pair)
loads.extend([
Force(attachment_pair[0], -force*relative_position/length),
Force(attachment_pair[1], force*relative_position/length),
])
return loads
class WrappingPathway(PathwayBase):
"""Pathway that wraps a geometry object.
Explanation
===========
A wrapping pathway interacts with a geometry object and forms a path that
wraps smoothly along its surface. The wrapping pathway along the geometry
object will be the geodesic that the geometry object defines based on the
two points. It will not interact with any other objects in the system, i.e.
a ``WrappingPathway`` will intersect other objects to ensure that the path
between its two ends (its attachments) is the shortest possible.
To explain the sign conventions used for pathway length, extension
velocity, and direction of applied forces, we can ignore the geometry with
which the wrapping pathway interacts. A wrapping pathway is made up of two
points that can move relative to each other, and a pair of equal and
opposite forces acting on the points. If the positive time-varying
Euclidean distance between the two points is defined, then the "extension
velocity" is the time derivative of this distance. The extension velocity
is positive when the two points are moving away from each other and
negative when moving closer to each other. The direction for the force
acting on either point is determined by constructing a unit vector directed
from the other point to this point. This establishes a sign convention such
that a positive force magnitude tends to push the points apart. The
following diagram shows the positive force sense and the distance between
the points::
P Q
o<--- F --->o
| |
|<--l(t)--->|
Examples
========
>>> from sympy.physics.mechanics import WrappingPathway
To construct a wrapping pathway, like other pathways, a pair of points must
be passed, followed by an instance of a wrapping geometry class as a
keyword argument. We'll use a cylinder with radius ``r`` and its axis
parallel to ``N.x`` passing through a point ``pO``.
>>> from sympy import symbols
>>> from sympy.physics.mechanics import Point, ReferenceFrame, WrappingCylinder
>>> r = symbols('r')
>>> N = ReferenceFrame('N')
>>> pA, pB, pO = Point('pA'), Point('pB'), Point('pO')
>>> cylinder = WrappingCylinder(r, pO, N.x)
>>> wrapping_pathway = WrappingPathway(pA, pB, cylinder)
>>> wrapping_pathway
WrappingPathway(pA, pB, geometry=WrappingCylinder(radius=r, point=pO,
axis=N.x))
Parameters
==========
attachment_1 : Point
First of the pair of ``Point`` objects between which the wrapping
pathway spans.
attachment_2 : Point
Second of the pair of ``Point`` objects between which the wrapping
pathway spans.
geometry : WrappingGeometryBase
Geometry about which the pathway wraps.
"""
def __init__(self, attachment_1, attachment_2, geometry):
"""Initializer for ``WrappingPathway``.
Parameters
==========
attachment_1 : Point
First of the pair of ``Point`` objects between which the wrapping
pathway spans.
attachment_2 : Point
Second of the pair of ``Point`` objects between which the wrapping
pathway spans.
geometry : WrappingGeometryBase
Geometry about which the pathway wraps.
The geometry about which the pathway wraps.
"""
super().__init__(attachment_1, attachment_2)
self.geometry = geometry
@property
def geometry(self):
"""Geometry around which the pathway wraps."""
return self._geometry
@geometry.setter
def geometry(self, geometry):
if hasattr(self, '_geometry'):
msg = (
f'Can\'t set attribute `geometry` to {repr(geometry)} as it '
f'is immutable.'
)
raise AttributeError(msg)
if not isinstance(geometry, WrappingGeometryBase):
msg = (
f'Value {repr(geometry)} passed to `geometry` was of type '
f'{type(geometry)}, must be {WrappingGeometryBase}.'
)
raise TypeError(msg)
self._geometry = geometry
@property
def length(self):
"""Exact analytical expression for the pathway's length."""
return self.geometry.geodesic_length(*self.attachments)
@property
def extension_velocity(self):
"""Exact analytical expression for the pathway's extension velocity."""
return self.length.diff(dynamicsymbols._t)
def to_loads(self, force):
"""Loads required by the equations of motion method classes.
Explanation
===========
``KanesMethod`` requires a list of ``Point``-``Vector`` tuples to be
passed to the ``loads`` parameters of its ``kanes_equations`` method
when constructing the equations of motion. This method acts as a
utility to produce the correctly-structred pairs of points and vectors
required so that these can be easily concatenated with other items in
the list of loads and passed to ``KanesMethod.kanes_equations``. These
loads are also in the correct form to also be passed to the other
equations of motion method classes, e.g. ``LagrangesMethod``.
Examples
========
The below example shows how to generate the loads produced in an
actuator that produces an expansile force ``F`` while wrapping around a
cylinder. First, create a cylinder with radius ``r`` and an axis
parallel to the ``N.z`` direction of the global frame ``N`` that also
passes through a point ``pO``.
>>> from sympy import symbols
>>> from sympy.physics.mechanics import (Point, ReferenceFrame,
... WrappingCylinder)
>>> N = ReferenceFrame('N')
>>> r = symbols('r', positive=True)
>>> pO = Point('pO')
>>> cylinder = WrappingCylinder(r, pO, N.z)
Create the pathway of the actuator using the ``WrappingPathway`` class,
defined to span between two points ``pA`` and ``pB``. Both points lie
on the surface of the cylinder and the location of ``pB`` is defined
relative to ``pA`` by the dynamics symbol ``q``.
>>> from sympy import cos, sin
>>> from sympy.physics.mechanics import WrappingPathway, dynamicsymbols
>>> q = dynamicsymbols('q')
>>> pA = Point('pA')
>>> pB = Point('pB')
>>> pA.set_pos(pO, r*N.x)
>>> pB.set_pos(pO, r*(cos(q)*N.x + sin(q)*N.y))
>>> pB.pos_from(pA)
(r*cos(q(t)) - r)*N.x + r*sin(q(t))*N.y
>>> pathway = WrappingPathway(pA, pB, cylinder)
Now create a symbol ``F`` to describe the magnitude of the (expansile)
force that will be produced along the pathway. The list of loads that
``KanesMethod`` requires can be produced by calling the pathway's
``to_loads`` method with ``F`` passed as the only argument.
>>> F = symbols('F')
>>> loads = pathway.to_loads(F)
>>> [load.__class__(load.location, load.vector.simplify()) for load in loads]
[(pA, F*N.y), (pB, F*sin(q(t))*N.x - F*cos(q(t))*N.y),
(pO, - F*sin(q(t))*N.x + F*(cos(q(t)) - 1)*N.y)]
Parameters
==========
force : Expr
Magnitude of the force acting along the length of the pathway. It
is assumed that this ``Expr`` represents an expansile force.
"""
pA, pB = self.attachments
pO = self.geometry.point
pA_force, pB_force = self.geometry.geodesic_end_vectors(pA, pB)
pO_force = -(pA_force + pB_force)
loads = [
Force(pA, force * pA_force),
Force(pB, force * pB_force),
Force(pO, force * pO_force),
]
return loads
def __repr__(self):
"""Representation of a ``WrappingPathway``."""
attachments = ', '.join(str(a) for a in self.attachments)
return (
f'{self.__class__.__name__}({attachments}, '
f'geometry={self.geometry})'
)
def _point_pair_relative_position(point_1, point_2):
"""The relative position between a pair of points."""
return point_2.pos_from(point_1)
def _point_pair_length(point_1, point_2):
"""The length of the direct linear path between two points."""
return _point_pair_relative_position(point_1, point_2).magnitude()
def _point_pair_extension_velocity(point_1, point_2):
"""The extension velocity of the direct linear path between two points."""
return _point_pair_length(point_1, point_2).diff(dynamicsymbols._t)
PK ]ZZZ (T/( /( $ sympy/physics/mechanics/rigidbody.pyfrom sympy import Symbol, S
from sympy.physics.vector import ReferenceFrame, Dyadic, Point, dot
from sympy.physics.mechanics.body_base import BodyBase
from sympy.physics.mechanics.inertia import inertia_of_point_mass, Inertia
from sympy.utilities.exceptions import sympy_deprecation_warning
__all__ = ['RigidBody']
class RigidBody(BodyBase):
"""An idealized rigid body.
Explanation
===========
This is essentially a container which holds the various components which
describe a rigid body: a name, mass, center of mass, reference frame, and
inertia.
All of these need to be supplied on creation, but can be changed
afterwards.
Attributes
==========
name : string
The body's name.
masscenter : Point
The point which represents the center of mass of the rigid body.
frame : ReferenceFrame
The ReferenceFrame which the rigid body is fixed in.
mass : Sympifyable
The body's mass.
inertia : (Dyadic, Point)
The body's inertia about a point; stored in a tuple as shown above.
potential_energy : Sympifyable
The potential energy of the RigidBody.
Examples
========
>>> from sympy import Symbol
>>> from sympy.physics.mechanics import ReferenceFrame, Point, RigidBody
>>> from sympy.physics.mechanics import outer
>>> m = Symbol('m')
>>> A = ReferenceFrame('A')
>>> P = Point('P')
>>> I = outer (A.x, A.x)
>>> inertia_tuple = (I, P)
>>> B = RigidBody('B', P, A, m, inertia_tuple)
>>> # Or you could change them afterwards
>>> m2 = Symbol('m2')
>>> B.mass = m2
"""
def __init__(self, name, masscenter=None, frame=None, mass=None,
inertia=None):
super().__init__(name, masscenter, mass)
if frame is None:
frame = ReferenceFrame(f'{name}_frame')
self.frame = frame
if inertia is None:
ixx = Symbol(f'{name}_ixx')
iyy = Symbol(f'{name}_iyy')
izz = Symbol(f'{name}_izz')
izx = Symbol(f'{name}_izx')
ixy = Symbol(f'{name}_ixy')
iyz = Symbol(f'{name}_iyz')
inertia = Inertia.from_inertia_scalars(self.masscenter, self.frame,
ixx, iyy, izz, ixy, iyz, izx)
self.inertia = inertia
def __repr__(self):
return (f'{self.__class__.__name__}({repr(self.name)}, masscenter='
f'{repr(self.masscenter)}, frame={repr(self.frame)}, mass='
f'{repr(self.mass)}, inertia={repr(self.inertia)})')
@property
def frame(self):
"""The ReferenceFrame fixed to the body."""
return self._frame
@frame.setter
def frame(self, F):
if not isinstance(F, ReferenceFrame):
raise TypeError("RigidBody frame must be a ReferenceFrame object.")
self._frame = F
@property
def x(self):
"""The basis Vector for the body, in the x direction. """
return self.frame.x
@property
def y(self):
"""The basis Vector for the body, in the y direction. """
return self.frame.y
@property
def z(self):
"""The basis Vector for the body, in the z direction. """
return self.frame.z
@property
def inertia(self):
"""The body's inertia about a point; stored as (Dyadic, Point)."""
return self._inertia
@inertia.setter
def inertia(self, I):
# check if I is of the form (Dyadic, Point)
if len(I) != 2 or not isinstance(I[0], Dyadic) or not isinstance(I[1], Point):
raise TypeError("RigidBody inertia must be a tuple of the form (Dyadic, Point).")
self._inertia = Inertia(I[0], I[1])
# have I S/O, want I S/S*
# I S/O = I S/S* + I S*/O; I S/S* = I S/O - I S*/O
# I_S/S* = I_S/O - I_S*/O
I_Ss_O = inertia_of_point_mass(self.mass,
self.masscenter.pos_from(I[1]),
self.frame)
self._central_inertia = I[0] - I_Ss_O
@property
def central_inertia(self):
"""The body's central inertia dyadic."""
return self._central_inertia
@central_inertia.setter
def central_inertia(self, I):
if not isinstance(I, Dyadic):
raise TypeError("RigidBody inertia must be a Dyadic object.")
self.inertia = Inertia(I, self.masscenter)
def linear_momentum(self, frame):
""" Linear momentum of the rigid body.
Explanation
===========
The linear momentum L, of a rigid body B, with respect to frame N is
given by:
``L = m * v``
where m is the mass of the rigid body, and v is the velocity of the mass
center of B in the frame N.
Parameters
==========
frame : ReferenceFrame
The frame in which linear momentum is desired.
Examples
========
>>> from sympy.physics.mechanics import Point, ReferenceFrame, outer
>>> from sympy.physics.mechanics import RigidBody, dynamicsymbols
>>> from sympy.physics.vector import init_vprinting
>>> init_vprinting(pretty_print=False)
>>> m, v = dynamicsymbols('m v')
>>> N = ReferenceFrame('N')
>>> P = Point('P')
>>> P.set_vel(N, v * N.x)
>>> I = outer (N.x, N.x)
>>> Inertia_tuple = (I, P)
>>> B = RigidBody('B', P, N, m, Inertia_tuple)
>>> B.linear_momentum(N)
m*v*N.x
"""
return self.mass * self.masscenter.vel(frame)
def angular_momentum(self, point, frame):
"""Returns the angular momentum of the rigid body about a point in the
given frame.
Explanation
===========
The angular momentum H of a rigid body B about some point O in a frame N
is given by:
``H = dot(I, w) + cross(r, m * v)``
where I and m are the central inertia dyadic and mass of rigid body B, w
is the angular velocity of body B in the frame N, r is the position
vector from point O to the mass center of B, and v is the velocity of
the mass center in the frame N.
Parameters
==========
point : Point
The point about which angular momentum is desired.
frame : ReferenceFrame
The frame in which angular momentum is desired.
Examples
========
>>> from sympy.physics.mechanics import Point, ReferenceFrame, outer
>>> from sympy.physics.mechanics import RigidBody, dynamicsymbols
>>> from sympy.physics.vector import init_vprinting
>>> init_vprinting(pretty_print=False)
>>> m, v, r, omega = dynamicsymbols('m v r omega')
>>> N = ReferenceFrame('N')
>>> b = ReferenceFrame('b')
>>> b.set_ang_vel(N, omega * b.x)
>>> P = Point('P')
>>> P.set_vel(N, 1 * N.x)
>>> I = outer(b.x, b.x)
>>> B = RigidBody('B', P, b, m, (I, P))
>>> B.angular_momentum(P, N)
omega*b.x
"""
I = self.central_inertia
w = self.frame.ang_vel_in(frame)
m = self.mass
r = self.masscenter.pos_from(point)
v = self.masscenter.vel(frame)
return I.dot(w) + r.cross(m * v)
def kinetic_energy(self, frame):
"""Kinetic energy of the rigid body.
Explanation
===========
The kinetic energy, T, of a rigid body, B, is given by:
``T = 1/2 * (dot(dot(I, w), w) + dot(m * v, v))``
where I and m are the central inertia dyadic and mass of rigid body B
respectively, w is the body's angular velocity, and v is the velocity of
the body's mass center in the supplied ReferenceFrame.
Parameters
==========
frame : ReferenceFrame
The RigidBody's angular velocity and the velocity of it's mass
center are typically defined with respect to an inertial frame but
any relevant frame in which the velocities are known can be
supplied.
Examples
========
>>> from sympy.physics.mechanics import Point, ReferenceFrame, outer
>>> from sympy.physics.mechanics import RigidBody
>>> from sympy import symbols
>>> m, v, r, omega = symbols('m v r omega')
>>> N = ReferenceFrame('N')
>>> b = ReferenceFrame('b')
>>> b.set_ang_vel(N, omega * b.x)
>>> P = Point('P')
>>> P.set_vel(N, v * N.x)
>>> I = outer (b.x, b.x)
>>> inertia_tuple = (I, P)
>>> B = RigidBody('B', P, b, m, inertia_tuple)
>>> B.kinetic_energy(N)
m*v**2/2 + omega**2/2
"""
rotational_KE = S.Half * dot(
self.frame.ang_vel_in(frame),
dot(self.central_inertia, self.frame.ang_vel_in(frame)))
translational_KE = S.Half * self.mass * dot(self.masscenter.vel(frame),
self.masscenter.vel(frame))
return rotational_KE + translational_KE
def set_potential_energy(self, scalar):
sympy_deprecation_warning(
"""
The sympy.physics.mechanics.RigidBody.set_potential_energy()
method is deprecated. Instead use
B.potential_energy = scalar
""",
deprecated_since_version="1.5",
active_deprecations_target="deprecated-set-potential-energy",
)
self.potential_energy = scalar
def parallel_axis(self, point, frame=None):
"""Returns the inertia dyadic of the body with respect to another point.
Parameters
==========
point : sympy.physics.vector.Point
The point to express the inertia dyadic about.
frame : sympy.physics.vector.ReferenceFrame
The reference frame used to construct the dyadic.
Returns
=======
inertia : sympy.physics.vector.Dyadic
The inertia dyadic of the rigid body expressed about the provided
point.
"""
if frame is None:
frame = self.frame
return self.central_inertia + inertia_of_point_mass(
self.mass, self.masscenter.pos_from(point), frame)
PK ]ZZZ+(|A� A� ! sympy/physics/mechanics/system.pyfrom functools import wraps
from sympy.core.basic import Basic
from sympy.matrices.immutable import ImmutableMatrix
from sympy.matrices.dense import Matrix, eye, zeros
from sympy.core.containers import OrderedSet
from sympy.physics.mechanics.actuator import ActuatorBase
from sympy.physics.mechanics.body_base import BodyBase
from sympy.physics.mechanics.functions import (
Lagrangian, _validate_coordinates, find_dynamicsymbols)
from sympy.physics.mechanics.joint import Joint
from sympy.physics.mechanics.kane import KanesMethod
from sympy.physics.mechanics.lagrange import LagrangesMethod
from sympy.physics.mechanics.loads import _parse_load, gravity
from sympy.physics.mechanics.method import _Methods
from sympy.physics.mechanics.particle import Particle
from sympy.physics.vector import Point, ReferenceFrame, dynamicsymbols
from sympy.utilities.iterables import iterable
from sympy.utilities.misc import filldedent
__all__ = ['SymbolicSystem', 'System']
def _reset_eom_method(method):
"""Decorator to reset the eom_method if a property is changed."""
@wraps(method)
def wrapper(self, *args, **kwargs):
self._eom_method = None
return method(self, *args, **kwargs)
return wrapper
class System(_Methods):
"""Class to define a multibody system and form its equations of motion.
Explanation
===========
A ``System`` instance stores the different objects associated with a model,
including bodies, joints, constraints, and other relevant information. With
all the relationships between components defined, the ``System`` can be used
to form the equations of motion using a backend, such as ``KanesMethod``.
The ``System`` has been designed to be compatible with third-party
libraries for greater flexibility and integration with other tools.
Attributes
==========
frame : ReferenceFrame
Inertial reference frame of the system.
fixed_point : Point
A fixed point in the inertial reference frame.
x : Vector
Unit vector fixed in the inertial reference frame.
y : Vector
Unit vector fixed in the inertial reference frame.
z : Vector
Unit vector fixed in the inertial reference frame.
q : ImmutableMatrix
Matrix of all the generalized coordinates, i.e. the independent
generalized coordinates stacked upon the dependent.
u : ImmutableMatrix
Matrix of all the generalized speeds, i.e. the independent generealized
speeds stacked upon the dependent.
q_ind : ImmutableMatrix
Matrix of the independent generalized coordinates.
q_dep : ImmutableMatrix
Matrix of the dependent generalized coordinates.
u_ind : ImmutableMatrix
Matrix of the independent generalized speeds.
u_dep : ImmutableMatrix
Matrix of the dependent generalized speeds.
u_aux : ImmutableMatrix
Matrix of auxiliary generalized speeds.
kdes : ImmutableMatrix
Matrix of the kinematical differential equations as expressions equated
to the zero matrix.
bodies : tuple of BodyBase subclasses
Tuple of all bodies that make up the system.
joints : tuple of Joint
Tuple of all joints that connect bodies in the system.
loads : tuple of LoadBase subclasses
Tuple of all loads that have been applied to the system.
actuators : tuple of ActuatorBase subclasses
Tuple of all actuators present in the system.
holonomic_constraints : ImmutableMatrix
Matrix with the holonomic constraints as expressions equated to the zero
matrix.
nonholonomic_constraints : ImmutableMatrix
Matrix with the nonholonomic constraints as expressions equated to the
zero matrix.
velocity_constraints : ImmutableMatrix
Matrix with the velocity constraints as expressions equated to the zero
matrix. These are by default derived as the time derivatives of the
holonomic constraints extended with the nonholonomic constraints.
eom_method : subclass of KanesMethod or LagrangesMethod
Backend for forming the equations of motion.
Examples
========
In the example below a cart with a pendulum is created. The cart moves along
the x axis of the rail and the pendulum rotates about the z axis. The length
of the pendulum is ``l`` with the pendulum represented as a particle. To
move the cart a time dependent force ``F`` is applied to the cart.
We first need to import some functions and create some of our variables.
>>> from sympy import symbols, simplify
>>> from sympy.physics.mechanics import (
... mechanics_printing, dynamicsymbols, RigidBody, Particle,
... ReferenceFrame, PrismaticJoint, PinJoint, System)
>>> mechanics_printing(pretty_print=False)
>>> g, l = symbols('g l')
>>> F = dynamicsymbols('F')
The next step is to create bodies. It is also useful to create a frame for
locating the particle with respect to the pin joint later on, as a particle
does not have a body-fixed frame.
>>> rail = RigidBody('rail')
>>> cart = RigidBody('cart')
>>> bob = Particle('bob')
>>> bob_frame = ReferenceFrame('bob_frame')
Initialize the system, with the rail as the Newtonian reference. The body is
also automatically added to the system.
>>> system = System.from_newtonian(rail)
>>> print(system.bodies[0])
rail
Create the joints, while immediately also adding them to the system.
>>> system.add_joints(
... PrismaticJoint('slider', rail, cart, joint_axis=rail.x),
... PinJoint('pin', cart, bob, joint_axis=cart.z,
... child_interframe=bob_frame,
... child_point=l * bob_frame.y)
... )
>>> system.joints
(PrismaticJoint: slider parent: rail child: cart,
PinJoint: pin parent: cart child: bob)
While adding the joints, the associated generalized coordinates, generalized
speeds, kinematic differential equations and bodies are also added to the
system.
>>> system.q
Matrix([
[q_slider],
[ q_pin]])
>>> system.u
Matrix([
[u_slider],
[ u_pin]])
>>> system.kdes
Matrix([
[u_slider - q_slider'],
[ u_pin - q_pin']])
>>> [body.name for body in system.bodies]
['rail', 'cart', 'bob']
With the kinematics established, we can now apply gravity and the cart force
``F``.
>>> system.apply_uniform_gravity(-g * system.y)
>>> system.add_loads((cart.masscenter, F * rail.x))
>>> system.loads
((rail_masscenter, - g*rail_mass*rail_frame.y),
(cart_masscenter, - cart_mass*g*rail_frame.y),
(bob_masscenter, - bob_mass*g*rail_frame.y),
(cart_masscenter, F*rail_frame.x))
With the entire system defined, we can now form the equations of motion.
Before forming the equations of motion, one can also run some checks that
will try to identify some common errors.
>>> system.validate_system()
>>> system.form_eoms()
Matrix([
[bob_mass*l*u_pin**2*sin(q_pin) - bob_mass*l*cos(q_pin)*u_pin'
- (bob_mass + cart_mass)*u_slider' + F],
[ -bob_mass*g*l*sin(q_pin) - bob_mass*l**2*u_pin'
- bob_mass*l*cos(q_pin)*u_slider']])
>>> simplify(system.mass_matrix)
Matrix([
[ bob_mass + cart_mass, bob_mass*l*cos(q_pin)],
[bob_mass*l*cos(q_pin), bob_mass*l**2]])
>>> system.forcing
Matrix([
[bob_mass*l*u_pin**2*sin(q_pin) + F],
[ -bob_mass*g*l*sin(q_pin)]])
The complexity of the above example can be increased if we add a constraint
to prevent the particle from moving in the horizontal (x) direction. This
can be done by adding a holonomic constraint. After which we should also
redefine what our (in)dependent generalized coordinates and speeds are.
>>> system.add_holonomic_constraints(
... bob.masscenter.pos_from(rail.masscenter).dot(system.x)
... )
>>> system.q_ind = system.get_joint('pin').coordinates
>>> system.q_dep = system.get_joint('slider').coordinates
>>> system.u_ind = system.get_joint('pin').speeds
>>> system.u_dep = system.get_joint('slider').speeds
With the updated system the equations of motion can be formed again.
>>> system.validate_system()
>>> system.form_eoms()
Matrix([[-bob_mass*g*l*sin(q_pin)
- bob_mass*l**2*u_pin'
- bob_mass*l*cos(q_pin)*u_slider'
- l*(bob_mass*l*u_pin**2*sin(q_pin)
- bob_mass*l*cos(q_pin)*u_pin'
- (bob_mass + cart_mass)*u_slider')*cos(q_pin)
- l*F*cos(q_pin)]])
>>> simplify(system.mass_matrix)
Matrix([
[bob_mass*l**2*sin(q_pin)**2, -cart_mass*l*cos(q_pin)],
[ l*cos(q_pin), 1]])
>>> simplify(system.forcing)
Matrix([
[-l*(bob_mass*g*sin(q_pin) + bob_mass*l*u_pin**2*sin(2*q_pin)/2
+ F*cos(q_pin))],
[
l*u_pin**2*sin(q_pin)]])
"""
def __init__(self, frame=None, fixed_point=None):
"""Initialize the system.
Parameters
==========
frame : ReferenceFrame, optional
The inertial frame of the system. If none is supplied, a new frame
will be created.
fixed_point : Point, optional
A fixed point in the inertial reference frame. If none is supplied,
a new fixed_point will be created.
"""
if frame is None:
frame = ReferenceFrame('inertial_frame')
elif not isinstance(frame, ReferenceFrame):
raise TypeError('Frame must be an instance of ReferenceFrame.')
self._frame = frame
if fixed_point is None:
fixed_point = Point('inertial_point')
elif not isinstance(fixed_point, Point):
raise TypeError('Fixed point must be an instance of Point.')
self._fixed_point = fixed_point
self._fixed_point.set_vel(self._frame, 0)
self._q_ind = ImmutableMatrix(1, 0, []).T
self._q_dep = ImmutableMatrix(1, 0, []).T
self._u_ind = ImmutableMatrix(1, 0, []).T
self._u_dep = ImmutableMatrix(1, 0, []).T
self._u_aux = ImmutableMatrix(1, 0, []).T
self._kdes = ImmutableMatrix(1, 0, []).T
self._hol_coneqs = ImmutableMatrix(1, 0, []).T
self._nonhol_coneqs = ImmutableMatrix(1, 0, []).T
self._vel_constrs = None
self._bodies = []
self._joints = []
self._loads = []
self._actuators = []
self._eom_method = None
@classmethod
def from_newtonian(cls, newtonian):
"""Constructs the system with respect to a Newtonian body."""
if isinstance(newtonian, Particle):
raise TypeError('A Particle has no frame so cannot act as '
'the Newtonian.')
system = cls(frame=newtonian.frame, fixed_point=newtonian.masscenter)
system.add_bodies(newtonian)
return system
@property
def fixed_point(self):
"""Fixed point in the inertial reference frame."""
return self._fixed_point
@property
def frame(self):
"""Inertial reference frame of the system."""
return self._frame
@property
def x(self):
"""Unit vector fixed in the inertial reference frame."""
return self._frame.x
@property
def y(self):
"""Unit vector fixed in the inertial reference frame."""
return self._frame.y
@property
def z(self):
"""Unit vector fixed in the inertial reference frame."""
return self._frame.z
@property
def bodies(self):
"""Tuple of all bodies that have been added to the system."""
return tuple(self._bodies)
@bodies.setter
@_reset_eom_method
def bodies(self, bodies):
bodies = self._objects_to_list(bodies)
self._check_objects(bodies, [], BodyBase, 'Bodies', 'bodies')
self._bodies = bodies
@property
def joints(self):
"""Tuple of all joints that have been added to the system."""
return tuple(self._joints)
@joints.setter
@_reset_eom_method
def joints(self, joints):
joints = self._objects_to_list(joints)
self._check_objects(joints, [], Joint, 'Joints', 'joints')
self._joints = []
self.add_joints(*joints)
@property
def loads(self):
"""Tuple of loads that have been applied on the system."""
return tuple(self._loads)
@loads.setter
@_reset_eom_method
def loads(self, loads):
loads = self._objects_to_list(loads)
self._loads = [_parse_load(load) for load in loads]
@property
def actuators(self):
"""Tuple of actuators present in the system."""
return tuple(self._actuators)
@actuators.setter
@_reset_eom_method
def actuators(self, actuators):
actuators = self._objects_to_list(actuators)
self._check_objects(actuators, [], ActuatorBase, 'Actuators',
'actuators')
self._actuators = actuators
@property
def q(self):
"""Matrix of all the generalized coordinates with the independent
stacked upon the dependent."""
return self._q_ind.col_join(self._q_dep)
@property
def u(self):
"""Matrix of all the generalized speeds with the independent stacked
upon the dependent."""
return self._u_ind.col_join(self._u_dep)
@property
def q_ind(self):
"""Matrix of the independent generalized coordinates."""
return self._q_ind
@q_ind.setter
@_reset_eom_method
def q_ind(self, q_ind):
self._q_ind, self._q_dep = self._parse_coordinates(
self._objects_to_list(q_ind), True, [], self.q_dep, 'coordinates')
@property
def q_dep(self):
"""Matrix of the dependent generalized coordinates."""
return self._q_dep
@q_dep.setter
@_reset_eom_method
def q_dep(self, q_dep):
self._q_ind, self._q_dep = self._parse_coordinates(
self._objects_to_list(q_dep), False, self.q_ind, [], 'coordinates')
@property
def u_ind(self):
"""Matrix of the independent generalized speeds."""
return self._u_ind
@u_ind.setter
@_reset_eom_method
def u_ind(self, u_ind):
self._u_ind, self._u_dep = self._parse_coordinates(
self._objects_to_list(u_ind), True, [], self.u_dep, 'speeds')
@property
def u_dep(self):
"""Matrix of the dependent generalized speeds."""
return self._u_dep
@u_dep.setter
@_reset_eom_method
def u_dep(self, u_dep):
self._u_ind, self._u_dep = self._parse_coordinates(
self._objects_to_list(u_dep), False, self.u_ind, [], 'speeds')
@property
def u_aux(self):
"""Matrix of auxiliary generalized speeds."""
return self._u_aux
@u_aux.setter
@_reset_eom_method
def u_aux(self, u_aux):
self._u_aux = self._parse_coordinates(
self._objects_to_list(u_aux), True, [], [], 'u_auxiliary')[0]
@property
def kdes(self):
"""Kinematical differential equations as expressions equated to the zero
matrix. These equations describe the coupling between the generalized
coordinates and the generalized speeds."""
return self._kdes
@kdes.setter
@_reset_eom_method
def kdes(self, kdes):
kdes = self._objects_to_list(kdes)
self._kdes = self._parse_expressions(
kdes, [], 'kinematic differential equations')
@property
def holonomic_constraints(self):
"""Matrix with the holonomic constraints as expressions equated to the
zero matrix."""
return self._hol_coneqs
@holonomic_constraints.setter
@_reset_eom_method
def holonomic_constraints(self, constraints):
constraints = self._objects_to_list(constraints)
self._hol_coneqs = self._parse_expressions(
constraints, [], 'holonomic constraints')
@property
def nonholonomic_constraints(self):
"""Matrix with the nonholonomic constraints as expressions equated to
the zero matrix."""
return self._nonhol_coneqs
@nonholonomic_constraints.setter
@_reset_eom_method
def nonholonomic_constraints(self, constraints):
constraints = self._objects_to_list(constraints)
self._nonhol_coneqs = self._parse_expressions(
constraints, [], 'nonholonomic constraints')
@property
def velocity_constraints(self):
"""Matrix with the velocity constraints as expressions equated to the
zero matrix. The velocity constraints are by default derived from the
holonomic and nonholonomic constraints unless they are explicitly set.
"""
if self._vel_constrs is None:
return self.holonomic_constraints.diff(dynamicsymbols._t).col_join(
self.nonholonomic_constraints)
return self._vel_constrs
@velocity_constraints.setter
@_reset_eom_method
def velocity_constraints(self, constraints):
if constraints is None:
self._vel_constrs = None
return
constraints = self._objects_to_list(constraints)
self._vel_constrs = self._parse_expressions(
constraints, [], 'velocity constraints')
@property
def eom_method(self):
"""Backend for forming the equations of motion."""
return self._eom_method
@staticmethod
def _objects_to_list(lst):
"""Helper to convert passed objects to a list."""
if not iterable(lst): # Only one object
return [lst]
return list(lst[:]) # converts Matrix and tuple to flattened list
@staticmethod
def _check_objects(objects, obj_lst, expected_type, obj_name, type_name):
"""Helper to check the objects that are being added to the system.
Explanation
===========
This method checks that the objects that are being added to the system
are of the correct type and have not already been added. If any of the
objects are not of the correct type or have already been added, then
an error is raised.
Parameters
==========
objects : iterable
The objects that would be added to the system.
obj_lst : list
The list of objects that are already in the system.
expected_type : type
The type that the objects should be.
obj_name : str
The name of the category of objects. This string is used to
formulate the error message for the user.
type_name : str
The name of the type that the objects should be. This string is used
to formulate the error message for the user.
"""
seen = set(obj_lst)
duplicates = set()
wrong_types = set()
for obj in objects:
if not isinstance(obj, expected_type):
wrong_types.add(obj)
if obj in seen:
duplicates.add(obj)
else:
seen.add(obj)
if wrong_types:
raise TypeError(f'{obj_name} {wrong_types} are not {type_name}.')
if duplicates:
raise ValueError(f'{obj_name} {duplicates} have already been added '
f'to the system.')
def _parse_coordinates(self, new_coords, independent, old_coords_ind,
old_coords_dep, coord_type='coordinates'):
"""Helper to parse coordinates and speeds."""
# Construct lists of the independent and dependent coordinates
coords_ind, coords_dep = old_coords_ind[:], old_coords_dep[:]
if not iterable(independent):
independent = [independent] * len(new_coords)
for coord, indep in zip(new_coords, independent):
if indep:
coords_ind.append(coord)
else:
coords_dep.append(coord)
# Check types and duplicates
current = {'coordinates': self.q_ind[:] + self.q_dep[:],
'speeds': self.u_ind[:] + self.u_dep[:],
'u_auxiliary': self._u_aux[:],
coord_type: coords_ind + coords_dep}
_validate_coordinates(**current)
return (ImmutableMatrix(1, len(coords_ind), coords_ind).T,
ImmutableMatrix(1, len(coords_dep), coords_dep).T)
@staticmethod
def _parse_expressions(new_expressions, old_expressions, name,
check_negatives=False):
"""Helper to parse expressions like constraints."""
old_expressions = old_expressions[:]
new_expressions = list(new_expressions) # Converts a possible tuple
if check_negatives:
check_exprs = old_expressions + [-expr for expr in old_expressions]
else:
check_exprs = old_expressions
System._check_objects(new_expressions, check_exprs, Basic, name,
'expressions')
for expr in new_expressions:
if expr == 0:
raise ValueError(f'Parsed {name} are zero.')
return ImmutableMatrix(1, len(old_expressions) + len(new_expressions),
old_expressions + new_expressions).T
@_reset_eom_method
def add_coordinates(self, *coordinates, independent=True):
"""Add generalized coordinate(s) to the system.
Parameters
==========
*coordinates : dynamicsymbols
One or more generalized coordinates to be added to the system.
independent : bool or list of bool, optional
Boolean whether a coordinate is dependent or independent. The
default is True, so the coordinates are added as independent by
default.
"""
self._q_ind, self._q_dep = self._parse_coordinates(
coordinates, independent, self.q_ind, self.q_dep, 'coordinates')
@_reset_eom_method
def add_speeds(self, *speeds, independent=True):
"""Add generalized speed(s) to the system.
Parameters
==========
*speeds : dynamicsymbols
One or more generalized speeds to be added to the system.
independent : bool or list of bool, optional
Boolean whether a speed is dependent or independent. The default is
True, so the speeds are added as independent by default.
"""
self._u_ind, self._u_dep = self._parse_coordinates(
speeds, independent, self.u_ind, self.u_dep, 'speeds')
@_reset_eom_method
def add_auxiliary_speeds(self, *speeds):
"""Add auxiliary speed(s) to the system.
Parameters
==========
*speeds : dynamicsymbols
One or more auxiliary speeds to be added to the system.
"""
self._u_aux = self._parse_coordinates(
speeds, True, self._u_aux, [], 'u_auxiliary')[0]
@_reset_eom_method
def add_kdes(self, *kdes):
"""Add kinematic differential equation(s) to the system.
Parameters
==========
*kdes : Expr
One or more kinematic differential equations.
"""
self._kdes = self._parse_expressions(
kdes, self.kdes, 'kinematic differential equations',
check_negatives=True)
@_reset_eom_method
def add_holonomic_constraints(self, *constraints):
"""Add holonomic constraint(s) to the system.
Parameters
==========
*constraints : Expr
One or more holonomic constraints, which are expressions that should
be zero.
"""
self._hol_coneqs = self._parse_expressions(
constraints, self._hol_coneqs, 'holonomic constraints',
check_negatives=True)
@_reset_eom_method
def add_nonholonomic_constraints(self, *constraints):
"""Add nonholonomic constraint(s) to the system.
Parameters
==========
*constraints : Expr
One or more nonholonomic constraints, which are expressions that
should be zero.
"""
self._nonhol_coneqs = self._parse_expressions(
constraints, self._nonhol_coneqs, 'nonholonomic constraints',
check_negatives=True)
@_reset_eom_method
def add_bodies(self, *bodies):
"""Add body(ies) to the system.
Parameters
==========
bodies : Particle or RigidBody
One or more bodies.
"""
self._check_objects(bodies, self.bodies, BodyBase, 'Bodies', 'bodies')
self._bodies.extend(bodies)
@_reset_eom_method
def add_loads(self, *loads):
"""Add load(s) to the system.
Parameters
==========
*loads : Force or Torque
One or more loads.
"""
loads = [_parse_load(load) for load in loads] # Checks the loads
self._loads.extend(loads)
@_reset_eom_method
def apply_uniform_gravity(self, acceleration):
"""Apply uniform gravity to all bodies in the system by adding loads.
Parameters
==========
acceleration : Vector
The acceleration due to gravity.
"""
self.add_loads(*gravity(acceleration, *self.bodies))
@_reset_eom_method
def add_actuators(self, *actuators):
"""Add actuator(s) to the system.
Parameters
==========
*actuators : subclass of ActuatorBase
One or more actuators.
"""
self._check_objects(actuators, self.actuators, ActuatorBase,
'Actuators', 'actuators')
self._actuators.extend(actuators)
@_reset_eom_method
def add_joints(self, *joints):
"""Add joint(s) to the system.
Explanation
===========
This methods adds one or more joints to the system including its
associated objects, i.e. generalized coordinates, generalized speeds,
kinematic differential equations and the bodies.
Parameters
==========
*joints : subclass of Joint
One or more joints.
Notes
=====
For the generalized coordinates, generalized speeds and bodies it is
checked whether they are already known by the system instance. If they
are, then they are not added. The kinematic differential equations are
however always added to the system, so you should not also manually add
those on beforehand.
"""
self._check_objects(joints, self.joints, Joint, 'Joints', 'joints')
self._joints.extend(joints)
coordinates, speeds, kdes, bodies = (OrderedSet() for _ in range(4))
for joint in joints:
coordinates.update(joint.coordinates)
speeds.update(joint.speeds)
kdes.update(joint.kdes)
bodies.update((joint.parent, joint.child))
coordinates = coordinates.difference(self.q)
speeds = speeds.difference(self.u)
kdes = kdes.difference(self.kdes[:] + (-self.kdes)[:])
bodies = bodies.difference(self.bodies)
self.add_coordinates(*tuple(coordinates))
self.add_speeds(*tuple(speeds))
self.add_kdes(*(kde for kde in tuple(kdes) if not kde == 0))
self.add_bodies(*tuple(bodies))
def get_body(self, name):
"""Retrieve a body from the system by name.
Parameters
==========
name : str
The name of the body to retrieve.
Returns
=======
RigidBody or Particle
The body with the given name, or None if no such body exists.
"""
for body in self._bodies:
if body.name == name:
return body
def get_joint(self, name):
"""Retrieve a joint from the system by name.
Parameters
==========
name : str
The name of the joint to retrieve.
Returns
=======
subclass of Joint
The joint with the given name, or None if no such joint exists.
"""
for joint in self._joints:
if joint.name == name:
return joint
def _form_eoms(self):
return self.form_eoms()
def form_eoms(self, eom_method=KanesMethod, **kwargs):
"""Form the equations of motion of the system.
Parameters
==========
eom_method : subclass of KanesMethod or LagrangesMethod
Backend class to be used for forming the equations of motion. The
default is ``KanesMethod``.
Returns
========
ImmutableMatrix
Vector of equations of motions.
Examples
========
This is a simple example for a one degree of freedom translational
spring-mass-damper.
>>> from sympy import S, symbols
>>> from sympy.physics.mechanics import (
... LagrangesMethod, dynamicsymbols, PrismaticJoint, Particle,
... RigidBody, System)
>>> q = dynamicsymbols('q')
>>> qd = dynamicsymbols('q', 1)
>>> m, k, b = symbols('m k b')
>>> wall = RigidBody('W')
>>> system = System.from_newtonian(wall)
>>> bob = Particle('P', mass=m)
>>> bob.potential_energy = S.Half * k * q**2
>>> system.add_joints(PrismaticJoint('J', wall, bob, q, qd))
>>> system.add_loads((bob.masscenter, b * qd * system.x))
>>> system.form_eoms(LagrangesMethod)
Matrix([[-b*Derivative(q(t), t) + k*q(t) + m*Derivative(q(t), (t, 2))]])
We can also solve for the states using the 'rhs' method.
>>> system.rhs()
Matrix([
[ Derivative(q(t), t)],
[(b*Derivative(q(t), t) - k*q(t))/m]])
"""
# KanesMethod does not accept empty iterables
loads = self.loads + tuple(
load for act in self.actuators for load in act.to_loads())
loads = loads if loads else None
if issubclass(eom_method, KanesMethod):
disallowed_kwargs = {
"frame", "q_ind", "u_ind", "kd_eqs", "q_dependent",
"u_dependent", "u_auxiliary", "configuration_constraints",
"velocity_constraints", "forcelist", "bodies"}
wrong_kwargs = disallowed_kwargs.intersection(kwargs)
if wrong_kwargs:
raise ValueError(
f"The following keyword arguments are not allowed to be "
f"overwritten in {eom_method.__name__}: {wrong_kwargs}.")
kwargs = {"frame": self.frame, "q_ind": self.q_ind,
"u_ind": self.u_ind, "kd_eqs": self.kdes,
"q_dependent": self.q_dep, "u_dependent": self.u_dep,
"configuration_constraints": self.holonomic_constraints,
"velocity_constraints": self.velocity_constraints,
"u_auxiliary": self.u_aux,
"forcelist": loads, "bodies": self.bodies,
"explicit_kinematics": False, **kwargs}
self._eom_method = eom_method(**kwargs)
elif issubclass(eom_method, LagrangesMethod):
disallowed_kwargs = {
"frame", "qs", "forcelist", "bodies", "hol_coneqs",
"nonhol_coneqs", "Lagrangian"}
wrong_kwargs = disallowed_kwargs.intersection(kwargs)
if wrong_kwargs:
raise ValueError(
f"The following keyword arguments are not allowed to be "
f"overwritten in {eom_method.__name__}: {wrong_kwargs}.")
kwargs = {"frame": self.frame, "qs": self.q, "forcelist": loads,
"bodies": self.bodies,
"hol_coneqs": self.holonomic_constraints,
"nonhol_coneqs": self.nonholonomic_constraints, **kwargs}
if "Lagrangian" not in kwargs:
kwargs["Lagrangian"] = Lagrangian(kwargs["frame"],
*kwargs["bodies"])
self._eom_method = eom_method(**kwargs)
else:
raise NotImplementedError(f'{eom_method} has not been implemented.')
return self.eom_method._form_eoms()
def rhs(self, inv_method=None):
"""Compute the equations of motion in the explicit form.
Parameters
==========
inv_method : str
The specific sympy inverse matrix calculation method to use. For a
list of valid methods, see
:meth:`~sympy.matrices.matrixbase.MatrixBase.inv`
Returns
========
ImmutableMatrix
Equations of motion in the explicit form.
See Also
========
sympy.physics.mechanics.kane.KanesMethod.rhs:
KanesMethod's ``rhs`` function.
sympy.physics.mechanics.lagrange.LagrangesMethod.rhs:
LagrangesMethod's ``rhs`` function.
"""
return self.eom_method.rhs(inv_method=inv_method)
@property
def mass_matrix(self):
r"""The mass matrix of the system.
Explanation
===========
The mass matrix $M_d$ and the forcing vector $f_d$ of a system describe
the system's dynamics according to the following equations:
.. math::
M_d \dot{u} = f_d
where $\dot{u}$ is the time derivative of the generalized speeds.
"""
return self.eom_method.mass_matrix
@property
def mass_matrix_full(self):
r"""The mass matrix of the system, augmented by the kinematic
differential equations in explicit or implicit form.
Explanation
===========
The full mass matrix $M_m$ and the full forcing vector $f_m$ of a system
describe the dynamics and kinematics according to the following
equation:
.. math::
M_m \dot{x} = f_m
where $x$ is the state vector stacking $q$ and $u$.
"""
return self.eom_method.mass_matrix_full
@property
def forcing(self):
"""The forcing vector of the system."""
return self.eom_method.forcing
@property
def forcing_full(self):
"""The forcing vector of the system, augmented by the kinematic
differential equations in explicit or implicit form."""
return self.eom_method.forcing_full
def validate_system(self, eom_method=KanesMethod, check_duplicates=False):
"""Validates the system using some basic checks.
Explanation
===========
This method validates the system based on the following checks:
- The number of dependent generalized coordinates should equal the
number of holonomic constraints.
- All generalized coordinates defined by the joints should also be known
to the system.
- If ``KanesMethod`` is used as a ``eom_method``:
- All generalized speeds and kinematic differential equations
defined by the joints should also be known to the system.
- The number of dependent generalized speeds should equal the number
of velocity constraints.
- The number of generalized coordinates should be less than or equal
to the number of generalized speeds.
- The number of generalized coordinates should equal the number of
kinematic differential equations.
- If ``LagrangesMethod`` is used as ``eom_method``:
- There should not be any generalized speeds that are not
derivatives of the generalized coordinates (this includes the
generalized speeds defined by the joints).
Parameters
==========
eom_method : subclass of KanesMethod or LagrangesMethod
Backend class that will be used for forming the equations of motion.
There are different checks for the different backends. The default
is ``KanesMethod``.
check_duplicates : bool
Boolean whether the system should be checked for duplicate
definitions. The default is False, because duplicates are already
checked when adding objects to the system.
Notes
=====
This method is not guaranteed to be backwards compatible as it may
improve over time. The method can become both more and less strict in
certain areas. However a well-defined system should always pass all
these tests.
"""
msgs = []
# Save some data in variables
n_hc = self.holonomic_constraints.shape[0]
n_vc = self.velocity_constraints.shape[0]
n_q_dep, n_u_dep = self.q_dep.shape[0], self.u_dep.shape[0]
q_set, u_set = set(self.q), set(self.u)
n_q, n_u = len(q_set), len(u_set)
# Check number of holonomic constraints
if n_q_dep != n_hc:
msgs.append(filldedent(f"""
The number of dependent generalized coordinates {n_q_dep} should be
equal to the number of holonomic constraints {n_hc}."""))
# Check if all joint coordinates and speeds are present
missing_q = set()
for joint in self.joints:
missing_q.update(set(joint.coordinates).difference(q_set))
if missing_q:
msgs.append(filldedent(f"""
The generalized coordinates {missing_q} used in joints are not added
to the system."""))
# Method dependent checks
if issubclass(eom_method, KanesMethod):
n_kdes = len(self.kdes)
missing_kdes, missing_u = set(), set()
for joint in self.joints:
missing_u.update(set(joint.speeds).difference(u_set))
missing_kdes.update(set(joint.kdes).difference(
self.kdes[:] + (-self.kdes)[:]))
if missing_u:
msgs.append(filldedent(f"""
The generalized speeds {missing_u} used in joints are not added
to the system."""))
if missing_kdes:
msgs.append(filldedent(f"""
The kinematic differential equations {missing_kdes} used in
joints are not added to the system."""))
if n_u_dep != n_vc:
msgs.append(filldedent(f"""
The number of dependent generalized speeds {n_u_dep} should be
equal to the number of velocity constraints {n_vc}."""))
if n_q > n_u:
msgs.append(filldedent(f"""
The number of generalized coordinates {n_q} should be less than
or equal to the number of generalized speeds {n_u}."""))
if n_u != n_kdes:
msgs.append(filldedent(f"""
The number of generalized speeds {n_u} should be equal to the
number of kinematic differential equations {n_kdes}."""))
elif issubclass(eom_method, LagrangesMethod):
not_qdots = set(self.u).difference(self.q.diff(dynamicsymbols._t))
for joint in self.joints:
not_qdots.update(set(
joint.speeds).difference(self.q.diff(dynamicsymbols._t)))
if not_qdots:
msgs.append(filldedent(f"""
The generalized speeds {not_qdots} are not supported by this
method. Only derivatives of the generalized coordinates are
supported. If these symbols are used in your expressions, then
this will result in wrong equations of motion."""))
if self.u_aux:
msgs.append(filldedent(f"""
This method does not support auxiliary speeds. If these symbols
are used in your expressions, then this will result in wrong
equations of motion. The auxiliary speeds are {self.u_aux}."""))
else:
raise NotImplementedError(f'{eom_method} has not been implemented.')
if check_duplicates: # Should be redundant
duplicates_to_check = [('generalized coordinates', self.q),
('generalized speeds', self.u),
('auxiliary speeds', self.u_aux),
('bodies', self.bodies),
('joints', self.joints)]
for name, lst in duplicates_to_check:
seen = set()
duplicates = {x for x in lst if x in seen or seen.add(x)}
if duplicates:
msgs.append(filldedent(f"""
The {name} {duplicates} exist multiple times within the
system."""))
if msgs:
raise ValueError('\n'.join(msgs))
class SymbolicSystem:
"""SymbolicSystem is a class that contains all the information about a
system in a symbolic format such as the equations of motions and the bodies
and loads in the system.
There are three ways that the equations of motion can be described for
Symbolic System:
[1] Explicit form where the kinematics and dynamics are combined
x' = F_1(x, t, r, p)
[2] Implicit form where the kinematics and dynamics are combined
M_2(x, p) x' = F_2(x, t, r, p)
[3] Implicit form where the kinematics and dynamics are separate
M_3(q, p) u' = F_3(q, u, t, r, p)
q' = G(q, u, t, r, p)
where
x : states, e.g. [q, u]
t : time
r : specified (exogenous) inputs
p : constants
q : generalized coordinates
u : generalized speeds
F_1 : right hand side of the combined equations in explicit form
F_2 : right hand side of the combined equations in implicit form
F_3 : right hand side of the dynamical equations in implicit form
M_2 : mass matrix of the combined equations in implicit form
M_3 : mass matrix of the dynamical equations in implicit form
G : right hand side of the kinematical differential equations
Parameters
==========
coord_states : ordered iterable of functions of time
This input will either be a collection of the coordinates or states
of the system depending on whether or not the speeds are also
given. If speeds are specified this input will be assumed to
be the coordinates otherwise this input will be assumed to
be the states.
right_hand_side : Matrix
This variable is the right hand side of the equations of motion in
any of the forms. The specific form will be assumed depending on
whether a mass matrix or coordinate derivatives are given.
speeds : ordered iterable of functions of time, optional
This is a collection of the generalized speeds of the system. If
given it will be assumed that the first argument (coord_states)
will represent the generalized coordinates of the system.
mass_matrix : Matrix, optional
The matrix of the implicit forms of the equations of motion (forms
[2] and [3]). The distinction between the forms is determined by
whether or not the coordinate derivatives are passed in. If
they are given form [3] will be assumed otherwise form [2] is
assumed.
coordinate_derivatives : Matrix, optional
The right hand side of the kinematical equations in explicit form.
If given it will be assumed that the equations of motion are being
entered in form [3].
alg_con : Iterable, optional
The indexes of the rows in the equations of motion that contain
algebraic constraints instead of differential equations. If the
equations are input in form [3], it will be assumed the indexes are
referencing the mass_matrix/right_hand_side combination and not the
coordinate_derivatives.
output_eqns : Dictionary, optional
Any output equations that are desired to be tracked are stored in a
dictionary where the key corresponds to the name given for the
specific equation and the value is the equation itself in symbolic
form
coord_idxs : Iterable, optional
If coord_states corresponds to the states rather than the
coordinates this variable will tell SymbolicSystem which indexes of
the states correspond to generalized coordinates.
speed_idxs : Iterable, optional
If coord_states corresponds to the states rather than the
coordinates this variable will tell SymbolicSystem which indexes of
the states correspond to generalized speeds.
bodies : iterable of Body/Rigidbody objects, optional
Iterable containing the bodies of the system
loads : iterable of load instances (described below), optional
Iterable containing the loads of the system where forces are given
by (point of application, force vector) and torques are given by
(reference frame acting upon, torque vector). Ex [(point, force),
(ref_frame, torque)]
Attributes
==========
coordinates : Matrix, shape(n, 1)
This is a matrix containing the generalized coordinates of the system
speeds : Matrix, shape(m, 1)
This is a matrix containing the generalized speeds of the system
states : Matrix, shape(o, 1)
This is a matrix containing the state variables of the system
alg_con : List
This list contains the indices of the algebraic constraints in the
combined equations of motion. The presence of these constraints
requires that a DAE solver be used instead of an ODE solver.
If the system is given in form [3] the alg_con variable will be
adjusted such that it is a representation of the combined kinematics
and dynamics thus make sure it always matches the mass matrix
entered.
dyn_implicit_mat : Matrix, shape(m, m)
This is the M matrix in form [3] of the equations of motion (the mass
matrix or generalized inertia matrix of the dynamical equations of
motion in implicit form).
dyn_implicit_rhs : Matrix, shape(m, 1)
This is the F vector in form [3] of the equations of motion (the right
hand side of the dynamical equations of motion in implicit form).
comb_implicit_mat : Matrix, shape(o, o)
This is the M matrix in form [2] of the equations of motion.
This matrix contains a block diagonal structure where the top
left block (the first rows) represent the matrix in the
implicit form of the kinematical equations and the bottom right
block (the last rows) represent the matrix in the implicit form
of the dynamical equations.
comb_implicit_rhs : Matrix, shape(o, 1)
This is the F vector in form [2] of the equations of motion. The top
part of the vector represents the right hand side of the implicit form
of the kinemaical equations and the bottom of the vector represents the
right hand side of the implicit form of the dynamical equations of
motion.
comb_explicit_rhs : Matrix, shape(o, 1)
This vector represents the right hand side of the combined equations of
motion in explicit form (form [1] from above).
kin_explicit_rhs : Matrix, shape(m, 1)
This is the right hand side of the explicit form of the kinematical
equations of motion as can be seen in form [3] (the G matrix).
output_eqns : Dictionary
If output equations were given they are stored in a dictionary where
the key corresponds to the name given for the specific equation and
the value is the equation itself in symbolic form
bodies : Tuple
If the bodies in the system were given they are stored in a tuple for
future access
loads : Tuple
If the loads in the system were given they are stored in a tuple for
future access. This includes forces and torques where forces are given
by (point of application, force vector) and torques are given by
(reference frame acted upon, torque vector).
Example
=======
As a simple example, the dynamics of a simple pendulum will be input into a
SymbolicSystem object manually. First some imports will be needed and then
symbols will be set up for the length of the pendulum (l), mass at the end
of the pendulum (m), and a constant for gravity (g). ::
>>> from sympy import Matrix, sin, symbols
>>> from sympy.physics.mechanics import dynamicsymbols, SymbolicSystem
>>> l, m, g = symbols('l m g')
The system will be defined by an angle of theta from the vertical and a
generalized speed of omega will be used where omega = theta_dot. ::
>>> theta, omega = dynamicsymbols('theta omega')
Now the equations of motion are ready to be formed and passed to the
SymbolicSystem object. ::
>>> kin_explicit_rhs = Matrix([omega])
>>> dyn_implicit_mat = Matrix([l**2 * m])
>>> dyn_implicit_rhs = Matrix([-g * l * m * sin(theta)])
>>> symsystem = SymbolicSystem([theta], dyn_implicit_rhs, [omega],
... dyn_implicit_mat)
Notes
=====
m : number of generalized speeds
n : number of generalized coordinates
o : number of states
"""
def __init__(self, coord_states, right_hand_side, speeds=None,
mass_matrix=None, coordinate_derivatives=None, alg_con=None,
output_eqns={}, coord_idxs=None, speed_idxs=None, bodies=None,
loads=None):
"""Initializes a SymbolicSystem object"""
# Extract information on speeds, coordinates and states
if speeds is None:
self._states = Matrix(coord_states)
if coord_idxs is None:
self._coordinates = None
else:
coords = [coord_states[i] for i in coord_idxs]
self._coordinates = Matrix(coords)
if speed_idxs is None:
self._speeds = None
else:
speeds_inter = [coord_states[i] for i in speed_idxs]
self._speeds = Matrix(speeds_inter)
else:
self._coordinates = Matrix(coord_states)
self._speeds = Matrix(speeds)
self._states = self._coordinates.col_join(self._speeds)
# Extract equations of motion form
if coordinate_derivatives is not None:
self._kin_explicit_rhs = coordinate_derivatives
self._dyn_implicit_rhs = right_hand_side
self._dyn_implicit_mat = mass_matrix
self._comb_implicit_rhs = None
self._comb_implicit_mat = None
self._comb_explicit_rhs = None
elif mass_matrix is not None:
self._kin_explicit_rhs = None
self._dyn_implicit_rhs = None
self._dyn_implicit_mat = None
self._comb_implicit_rhs = right_hand_side
self._comb_implicit_mat = mass_matrix
self._comb_explicit_rhs = None
else:
self._kin_explicit_rhs = None
self._dyn_implicit_rhs = None
self._dyn_implicit_mat = None
self._comb_implicit_rhs = None
self._comb_implicit_mat = None
self._comb_explicit_rhs = right_hand_side
# Set the remainder of the inputs as instance attributes
if alg_con is not None and coordinate_derivatives is not None:
alg_con = [i + len(coordinate_derivatives) for i in alg_con]
self._alg_con = alg_con
self.output_eqns = output_eqns
# Change the body and loads iterables to tuples if they are not tuples
# already
if not isinstance(bodies, tuple) and bodies is not None:
bodies = tuple(bodies)
if not isinstance(loads, tuple) and loads is not None:
loads = tuple(loads)
self._bodies = bodies
self._loads = loads
@property
def coordinates(self):
"""Returns the column matrix of the generalized coordinates"""
if self._coordinates is None:
raise AttributeError("The coordinates were not specified.")
else:
return self._coordinates
@property
def speeds(self):
"""Returns the column matrix of generalized speeds"""
if self._speeds is None:
raise AttributeError("The speeds were not specified.")
else:
return self._speeds
@property
def states(self):
"""Returns the column matrix of the state variables"""
return self._states
@property
def alg_con(self):
"""Returns a list with the indices of the rows containing algebraic
constraints in the combined form of the equations of motion"""
return self._alg_con
@property
def dyn_implicit_mat(self):
"""Returns the matrix, M, corresponding to the dynamic equations in
implicit form, M x' = F, where the kinematical equations are not
included"""
if self._dyn_implicit_mat is None:
raise AttributeError("dyn_implicit_mat is not specified for "
"equations of motion form [1] or [2].")
else:
return self._dyn_implicit_mat
@property
def dyn_implicit_rhs(self):
"""Returns the column matrix, F, corresponding to the dynamic equations
in implicit form, M x' = F, where the kinematical equations are not
included"""
if self._dyn_implicit_rhs is None:
raise AttributeError("dyn_implicit_rhs is not specified for "
"equations of motion form [1] or [2].")
else:
return self._dyn_implicit_rhs
@property
def comb_implicit_mat(self):
"""Returns the matrix, M, corresponding to the equations of motion in
implicit form (form [2]), M x' = F, where the kinematical equations are
included"""
if self._comb_implicit_mat is None:
if self._dyn_implicit_mat is not None:
num_kin_eqns = len(self._kin_explicit_rhs)
num_dyn_eqns = len(self._dyn_implicit_rhs)
zeros1 = zeros(num_kin_eqns, num_dyn_eqns)
zeros2 = zeros(num_dyn_eqns, num_kin_eqns)
inter1 = eye(num_kin_eqns).row_join(zeros1)
inter2 = zeros2.row_join(self._dyn_implicit_mat)
self._comb_implicit_mat = inter1.col_join(inter2)
return self._comb_implicit_mat
else:
raise AttributeError("comb_implicit_mat is not specified for "
"equations of motion form [1].")
else:
return self._comb_implicit_mat
@property
def comb_implicit_rhs(self):
"""Returns the column matrix, F, corresponding to the equations of
motion in implicit form (form [2]), M x' = F, where the kinematical
equations are included"""
if self._comb_implicit_rhs is None:
if self._dyn_implicit_rhs is not None:
kin_inter = self._kin_explicit_rhs
dyn_inter = self._dyn_implicit_rhs
self._comb_implicit_rhs = kin_inter.col_join(dyn_inter)
return self._comb_implicit_rhs
else:
raise AttributeError("comb_implicit_mat is not specified for "
"equations of motion in form [1].")
else:
return self._comb_implicit_rhs
def compute_explicit_form(self):
"""If the explicit right hand side of the combined equations of motion
is to provided upon initialization, this method will calculate it. This
calculation can potentially take awhile to compute."""
if self._comb_explicit_rhs is not None:
raise AttributeError("comb_explicit_rhs is already formed.")
inter1 = getattr(self, 'kin_explicit_rhs', None)
if inter1 is not None:
inter2 = self._dyn_implicit_mat.LUsolve(self._dyn_implicit_rhs)
out = inter1.col_join(inter2)
else:
out = self._comb_implicit_mat.LUsolve(self._comb_implicit_rhs)
self._comb_explicit_rhs = out
@property
def comb_explicit_rhs(self):
"""Returns the right hand side of the equations of motion in explicit
form, x' = F, where the kinematical equations are included"""
if self._comb_explicit_rhs is None:
raise AttributeError("Please run .combute_explicit_form before "
"attempting to access comb_explicit_rhs.")
else:
return self._comb_explicit_rhs
@property
def kin_explicit_rhs(self):
"""Returns the right hand side of the kinematical equations in explicit
form, q' = G"""
if self._kin_explicit_rhs is None:
raise AttributeError("kin_explicit_rhs is not specified for "
"equations of motion form [1] or [2].")
else:
return self._kin_explicit_rhs
def dynamic_symbols(self):
"""Returns a column matrix containing all of the symbols in the system
that depend on time"""
# Create a list of all of the expressions in the equations of motion
if self._comb_explicit_rhs is None:
eom_expressions = (self.comb_implicit_mat[:] +
self.comb_implicit_rhs[:])
else:
eom_expressions = (self._comb_explicit_rhs[:])
functions_of_time = set()
for expr in eom_expressions:
functions_of_time = functions_of_time.union(
find_dynamicsymbols(expr))
functions_of_time = functions_of_time.union(self._states)
return tuple(functions_of_time)
def constant_symbols(self):
"""Returns a column matrix containing all of the symbols in the system
that do not depend on time"""
# Create a list of all of the expressions in the equations of motion
if self._comb_explicit_rhs is None:
eom_expressions = (self.comb_implicit_mat[:] +
self.comb_implicit_rhs[:])
else:
eom_expressions = (self._comb_explicit_rhs[:])
constants = set()
for expr in eom_expressions:
constants = constants.union(expr.free_symbols)
constants.remove(dynamicsymbols._t)
return tuple(constants)
@property
def bodies(self):
"""Returns the bodies in the system"""
if self._bodies is None:
raise AttributeError("bodies were not specified for the system.")
else:
return self._bodies
@property
def loads(self):
"""Returns the loads in the system"""
if self._loads is None:
raise AttributeError("loads were not specified for the system.")
else:
return self._loads
PK ]ZZZ?@l
_T _T , sympy/physics/mechanics/wrapping_geometry.py"""Geometry objects for use by wrapping pathways."""
from abc import ABC, abstractmethod
from sympy import Integer, acos, pi, sqrt, sympify, tan
from sympy.core.relational import Eq
from sympy.functions.elementary.trigonometric import atan2
from sympy.polys.polytools import cancel
from sympy.physics.vector import Vector, dot
from sympy.simplify.simplify import trigsimp
__all__ = [
'WrappingGeometryBase',
'WrappingCylinder',
'WrappingSphere',
]
class WrappingGeometryBase(ABC):
"""Abstract base class for all geometry classes to inherit from.
Notes
=====
Instances of this class cannot be directly instantiated by users. However,
it can be used to created custom geometry types through subclassing.
"""
@property
@abstractmethod
def point(cls):
"""The point with which the geometry is associated."""
pass
@abstractmethod
def point_on_surface(self, point):
"""Returns ``True`` if a point is on the geometry's surface.
Parameters
==========
point : Point
The point for which it's to be ascertained if it's on the
geometry's surface or not.
"""
pass
@abstractmethod
def geodesic_length(self, point_1, point_2):
"""Returns the shortest distance between two points on a geometry's
surface.
Parameters
==========
point_1 : Point
The point from which the geodesic length should be calculated.
point_2 : Point
The point to which the geodesic length should be calculated.
"""
pass
@abstractmethod
def geodesic_end_vectors(self, point_1, point_2):
"""The vectors parallel to the geodesic at the two end points.
Parameters
==========
point_1 : Point
The point from which the geodesic originates.
point_2 : Point
The point at which the geodesic terminates.
"""
pass
def __repr__(self):
"""Default representation of a geometry object."""
return f'{self.__class__.__name__}()'
class WrappingSphere(WrappingGeometryBase):
"""A solid spherical object.
Explanation
===========
A wrapping geometry that allows for circular arcs to be defined between
pairs of points. These paths are always geodetic (the shortest possible).
Examples
========
To create a ``WrappingSphere`` instance, a ``Symbol`` denoting its radius
and ``Point`` at which its center will be located are needed:
>>> from sympy import symbols
>>> from sympy.physics.mechanics import Point, WrappingSphere
>>> r = symbols('r')
>>> pO = Point('pO')
A sphere with radius ``r`` centered on ``pO`` can be instantiated with:
>>> WrappingSphere(r, pO)
WrappingSphere(radius=r, point=pO)
Parameters
==========
radius : Symbol
Radius of the sphere. This symbol must represent a value that is
positive and constant, i.e. it cannot be a dynamic symbol, nor can it
be an expression.
point : Point
A point at which the sphere is centered.
See Also
========
WrappingCylinder: Cylindrical geometry where the wrapping direction can be
defined.
"""
def __init__(self, radius, point):
"""Initializer for ``WrappingSphere``.
Parameters
==========
radius : Symbol
The radius of the sphere.
point : Point
A point on which the sphere is centered.
"""
self.radius = radius
self.point = point
@property
def radius(self):
"""Radius of the sphere."""
return self._radius
@radius.setter
def radius(self, radius):
self._radius = radius
@property
def point(self):
"""A point on which the sphere is centered."""
return self._point
@point.setter
def point(self, point):
self._point = point
def point_on_surface(self, point):
"""Returns ``True`` if a point is on the sphere's surface.
Parameters
==========
point : Point
The point for which it's to be ascertained if it's on the sphere's
surface or not. This point's position relative to the sphere's
center must be a simple expression involving the radius of the
sphere, otherwise this check will likely not work.
"""
point_vector = point.pos_from(self.point)
if isinstance(point_vector, Vector):
point_radius_squared = dot(point_vector, point_vector)
else:
point_radius_squared = point_vector**2
return Eq(point_radius_squared, self.radius**2) == True
def geodesic_length(self, point_1, point_2):
r"""Returns the shortest distance between two points on the sphere's
surface.
Explanation
===========
The geodesic length, i.e. the shortest arc along the surface of a
sphere, connecting two points can be calculated using the formula:
.. math::
l = \arccos\left(\mathbf{v}_1 \cdot \mathbf{v}_2\right)
where $\mathbf{v}_1$ and $\mathbf{v}_2$ are the unit vectors from the
sphere's center to the first and second points on the sphere's surface
respectively. Note that the actual path that the geodesic will take is
undefined when the two points are directly opposite one another.
Examples
========
A geodesic length can only be calculated between two points on the
sphere's surface. Firstly, a ``WrappingSphere`` instance must be
created along with two points that will lie on its surface:
>>> from sympy import symbols
>>> from sympy.physics.mechanics import (Point, ReferenceFrame,
... WrappingSphere)
>>> N = ReferenceFrame('N')
>>> r = symbols('r')
>>> pO = Point('pO')
>>> pO.set_vel(N, 0)
>>> sphere = WrappingSphere(r, pO)
>>> p1 = Point('p1')
>>> p2 = Point('p2')
Let's assume that ``p1`` lies at a distance of ``r`` in the ``N.x``
direction from ``pO`` and that ``p2`` is located on the sphere's
surface in the ``N.y + N.z`` direction from ``pO``. These positions can
be set with:
>>> p1.set_pos(pO, r*N.x)
>>> p1.pos_from(pO)
r*N.x
>>> p2.set_pos(pO, r*(N.y + N.z).normalize())
>>> p2.pos_from(pO)
sqrt(2)*r/2*N.y + sqrt(2)*r/2*N.z
The geodesic length, which is in this case is a quarter of the sphere's
circumference, can be calculated using the ``geodesic_length`` method:
>>> sphere.geodesic_length(p1, p2)
pi*r/2
If the ``geodesic_length`` method is passed an argument, the ``Point``
that doesn't lie on the sphere's surface then a ``ValueError`` is
raised because it's not possible to calculate a value in this case.
Parameters
==========
point_1 : Point
Point from which the geodesic length should be calculated.
point_2 : Point
Point to which the geodesic length should be calculated.
"""
for point in (point_1, point_2):
if not self.point_on_surface(point):
msg = (
f'Geodesic length cannot be calculated as point {point} '
f'with radius {point.pos_from(self.point).magnitude()} '
f'from the sphere\'s center {self.point} does not lie on '
f'the surface of {self} with radius {self.radius}.'
)
raise ValueError(msg)
point_1_vector = point_1.pos_from(self.point).normalize()
point_2_vector = point_2.pos_from(self.point).normalize()
central_angle = acos(point_2_vector.dot(point_1_vector))
geodesic_length = self.radius*central_angle
return geodesic_length
def geodesic_end_vectors(self, point_1, point_2):
"""The vectors parallel to the geodesic at the two end points.
Parameters
==========
point_1 : Point
The point from which the geodesic originates.
point_2 : Point
The point at which the geodesic terminates.
"""
pA, pB = point_1, point_2
pO = self.point
pA_vec = pA.pos_from(pO)
pB_vec = pB.pos_from(pO)
if pA_vec.cross(pB_vec) == 0:
msg = (
f'Can\'t compute geodesic end vectors for the pair of points '
f'{pA} and {pB} on a sphere {self} as they are diametrically '
f'opposed, thus the geodesic is not defined.'
)
raise ValueError(msg)
return (
pA_vec.cross(pB.pos_from(pA)).cross(pA_vec).normalize(),
pB_vec.cross(pA.pos_from(pB)).cross(pB_vec).normalize(),
)
def __repr__(self):
"""Representation of a ``WrappingSphere``."""
return (
f'{self.__class__.__name__}(radius={self.radius}, '
f'point={self.point})'
)
class WrappingCylinder(WrappingGeometryBase):
"""A solid (infinite) cylindrical object.
Explanation
===========
A wrapping geometry that allows for circular arcs to be defined between
pairs of points. These paths are always geodetic (the shortest possible) in
the sense that they will be a straight line on the unwrapped cylinder's
surface. However, it is also possible for a direction to be specified, i.e.
paths can be influenced such that they either wrap along the shortest side
or the longest side of the cylinder. To define these directions, rotations
are in the positive direction following the right-hand rule.
Examples
========
To create a ``WrappingCylinder`` instance, a ``Symbol`` denoting its
radius, a ``Vector`` defining its axis, and a ``Point`` through which its
axis passes are needed:
>>> from sympy import symbols
>>> from sympy.physics.mechanics import (Point, ReferenceFrame,
... WrappingCylinder)
>>> N = ReferenceFrame('N')
>>> r = symbols('r')
>>> pO = Point('pO')
>>> ax = N.x
A cylinder with radius ``r``, and axis parallel to ``N.x`` passing through
``pO`` can be instantiated with:
>>> WrappingCylinder(r, pO, ax)
WrappingCylinder(radius=r, point=pO, axis=N.x)
Parameters
==========
radius : Symbol
The radius of the cylinder.
point : Point
A point through which the cylinder's axis passes.
axis : Vector
The axis along which the cylinder is aligned.
See Also
========
WrappingSphere: Spherical geometry where the wrapping direction is always
geodetic.
"""
def __init__(self, radius, point, axis):
"""Initializer for ``WrappingCylinder``.
Parameters
==========
radius : Symbol
The radius of the cylinder. This symbol must represent a value that
is positive and constant, i.e. it cannot be a dynamic symbol.
point : Point
A point through which the cylinder's axis passes.
axis : Vector
The axis along which the cylinder is aligned.
"""
self.radius = radius
self.point = point
self.axis = axis
@property
def radius(self):
"""Radius of the cylinder."""
return self._radius
@radius.setter
def radius(self, radius):
self._radius = radius
@property
def point(self):
"""A point through which the cylinder's axis passes."""
return self._point
@point.setter
def point(self, point):
self._point = point
@property
def axis(self):
"""Axis along which the cylinder is aligned."""
return self._axis
@axis.setter
def axis(self, axis):
self._axis = axis.normalize()
def point_on_surface(self, point):
"""Returns ``True`` if a point is on the cylinder's surface.
Parameters
==========
point : Point
The point for which it's to be ascertained if it's on the
cylinder's surface or not. This point's position relative to the
cylinder's axis must be a simple expression involving the radius of
the sphere, otherwise this check will likely not work.
"""
relative_position = point.pos_from(self.point)
parallel = relative_position.dot(self.axis) * self.axis
point_vector = relative_position - parallel
if isinstance(point_vector, Vector):
point_radius_squared = dot(point_vector, point_vector)
else:
point_radius_squared = point_vector**2
return Eq(trigsimp(point_radius_squared), self.radius**2) == True
def geodesic_length(self, point_1, point_2):
"""The shortest distance between two points on a geometry's surface.
Explanation
===========
The geodesic length, i.e. the shortest arc along the surface of a
cylinder, connecting two points. It can be calculated using Pythagoras'
theorem. The first short side is the distance between the two points on
the cylinder's surface parallel to the cylinder's axis. The second
short side is the arc of a circle between the two points of the
cylinder's surface perpendicular to the cylinder's axis. The resulting
hypotenuse is the geodesic length.
Examples
========
A geodesic length can only be calculated between two points on the
cylinder's surface. Firstly, a ``WrappingCylinder`` instance must be
created along with two points that will lie on its surface:
>>> from sympy import symbols, cos, sin
>>> from sympy.physics.mechanics import (Point, ReferenceFrame,
... WrappingCylinder, dynamicsymbols)
>>> N = ReferenceFrame('N')
>>> r = symbols('r')
>>> pO = Point('pO')
>>> pO.set_vel(N, 0)
>>> cylinder = WrappingCylinder(r, pO, N.x)
>>> p1 = Point('p1')
>>> p2 = Point('p2')
Let's assume that ``p1`` is located at ``N.x + r*N.y`` relative to
``pO`` and that ``p2`` is located at ``r*(cos(q)*N.y + sin(q)*N.z)``
relative to ``pO``, where ``q(t)`` is a generalized coordinate
specifying the angle rotated around the ``N.x`` axis according to the
right-hand rule where ``N.y`` is zero. These positions can be set with:
>>> q = dynamicsymbols('q')
>>> p1.set_pos(pO, N.x + r*N.y)
>>> p1.pos_from(pO)
N.x + r*N.y
>>> p2.set_pos(pO, r*(cos(q)*N.y + sin(q)*N.z).normalize())
>>> p2.pos_from(pO).simplify()
r*cos(q(t))*N.y + r*sin(q(t))*N.z
The geodesic length, which is in this case a is the hypotenuse of a
right triangle where the other two side lengths are ``1`` (parallel to
the cylinder's axis) and ``r*q(t)`` (parallel to the cylinder's cross
section), can be calculated using the ``geodesic_length`` method:
>>> cylinder.geodesic_length(p1, p2).simplify()
sqrt(r**2*q(t)**2 + 1)
If the ``geodesic_length`` method is passed an argument ``Point`` that
doesn't lie on the sphere's surface then a ``ValueError`` is raised
because it's not possible to calculate a value in this case.
Parameters
==========
point_1 : Point
Point from which the geodesic length should be calculated.
point_2 : Point
Point to which the geodesic length should be calculated.
"""
for point in (point_1, point_2):
if not self.point_on_surface(point):
msg = (
f'Geodesic length cannot be calculated as point {point} '
f'with radius {point.pos_from(self.point).magnitude()} '
f'from the cylinder\'s center {self.point} does not lie on '
f'the surface of {self} with radius {self.radius} and axis '
f'{self.axis}.'
)
raise ValueError(msg)
relative_position = point_2.pos_from(point_1)
parallel_length = relative_position.dot(self.axis)
point_1_relative_position = point_1.pos_from(self.point)
point_1_perpendicular_vector = (
point_1_relative_position
- point_1_relative_position.dot(self.axis)*self.axis
).normalize()
point_2_relative_position = point_2.pos_from(self.point)
point_2_perpendicular_vector = (
point_2_relative_position
- point_2_relative_position.dot(self.axis)*self.axis
).normalize()
central_angle = _directional_atan(
cancel(point_1_perpendicular_vector
.cross(point_2_perpendicular_vector)
.dot(self.axis)),
cancel(point_1_perpendicular_vector.dot(point_2_perpendicular_vector)),
)
planar_arc_length = self.radius*central_angle
geodesic_length = sqrt(parallel_length**2 + planar_arc_length**2)
return geodesic_length
def geodesic_end_vectors(self, point_1, point_2):
"""The vectors parallel to the geodesic at the two end points.
Parameters
==========
point_1 : Point
The point from which the geodesic originates.
point_2 : Point
The point at which the geodesic terminates.
"""
point_1_from_origin_point = point_1.pos_from(self.point)
point_2_from_origin_point = point_2.pos_from(self.point)
if point_1_from_origin_point == point_2_from_origin_point:
msg = (
f'Cannot compute geodesic end vectors for coincident points '
f'{point_1} and {point_2} as no geodesic exists.'
)
raise ValueError(msg)
point_1_parallel = point_1_from_origin_point.dot(self.axis) * self.axis
point_2_parallel = point_2_from_origin_point.dot(self.axis) * self.axis
point_1_normal = (point_1_from_origin_point - point_1_parallel)
point_2_normal = (point_2_from_origin_point - point_2_parallel)
if point_1_normal == point_2_normal:
point_1_perpendicular = Vector(0)
point_2_perpendicular = Vector(0)
else:
point_1_perpendicular = self.axis.cross(point_1_normal).normalize()
point_2_perpendicular = -self.axis.cross(point_2_normal).normalize()
geodesic_length = self.geodesic_length(point_1, point_2)
relative_position = point_2.pos_from(point_1)
parallel_length = relative_position.dot(self.axis)
planar_arc_length = sqrt(geodesic_length**2 - parallel_length**2)
point_1_vector = (
planar_arc_length * point_1_perpendicular
+ parallel_length * self.axis
).normalize()
point_2_vector = (
planar_arc_length * point_2_perpendicular
- parallel_length * self.axis
).normalize()
return (point_1_vector, point_2_vector)
def __repr__(self):
"""Representation of a ``WrappingCylinder``."""
return (
f'{self.__class__.__name__}(radius={self.radius}, '
f'point={self.point}, axis={self.axis})'
)
def _directional_atan(numerator, denominator):
"""Compute atan in a directional sense as required for geodesics.
Explanation
===========
To be able to control the direction of the geodesic length along the
surface of a cylinder a dedicated arctangent function is needed that
properly handles the directionality of different case. This function
ensures that the central angle is always positive but shifting the case
where ``atan2`` would return a negative angle to be centered around
``2*pi``.
Notes
=====
This function only handles very specific cases, i.e. the ones that are
expected to be encountered when calculating symbolic geodesics on uniformly
curved surfaces. As such, ``NotImplemented`` errors can be raised in many
cases. This function is named with a leader underscore to indicate that it
only aims to provide very specific functionality within the private scope
of this module.
"""
if numerator.is_number and denominator.is_number:
angle = atan2(numerator, denominator)
if angle < 0:
angle += 2 * pi
elif numerator.is_number:
msg = (
f'Cannot compute a directional atan when the numerator {numerator} '
f'is numeric and the denominator {denominator} is symbolic.'
)
raise NotImplementedError(msg)
elif denominator.is_number:
msg = (
f'Cannot compute a directional atan when the numerator {numerator} '
f'is symbolic and the denominator {denominator} is numeric.'
)
raise NotImplementedError(msg)
else:
ratio = sympify(trigsimp(numerator / denominator))
if isinstance(ratio, tan):
angle = ratio.args[0]
elif (
ratio.is_Mul
and ratio.args[0] == Integer(-1)
and isinstance(ratio.args[1], tan)
):
angle = 2 * pi - ratio.args[1].args[0]
else:
msg = f'Cannot compute a directional atan for the value {ratio}.'
raise NotImplementedError(msg)
return angle
PK ]ZZZ�ȫIo o sympy/physics/optics/__init__.py__all__ = [
'TWave',
'RayTransferMatrix', 'FreeSpace', 'FlatRefraction', 'CurvedRefraction',
'FlatMirror', 'CurvedMirror', 'ThinLens', 'GeometricRay', 'BeamParameter',
'waist2rayleigh', 'rayleigh2waist', 'geometric_conj_ab',
'geometric_conj_af', 'geometric_conj_bf', 'gaussian_conj',
'conjugate_gauss_beams',
'Medium',
'refraction_angle', 'deviation', 'fresnel_coefficients', 'brewster_angle',
'critical_angle', 'lens_makers_formula', 'mirror_formula', 'lens_formula',
'hyperfocal_distance', 'transverse_magnification',
'jones_vector', 'stokes_vector', 'jones_2_stokes', 'linear_polarizer',
'phase_retarder', 'half_wave_retarder', 'quarter_wave_retarder',
'transmissive_filter', 'reflective_filter', 'mueller_matrix',
'polarizing_beam_splitter',
]
from .waves import TWave
from .gaussopt import (RayTransferMatrix, FreeSpace, FlatRefraction,
CurvedRefraction, FlatMirror, CurvedMirror, ThinLens, GeometricRay,
BeamParameter, waist2rayleigh, rayleigh2waist, geometric_conj_ab,
geometric_conj_af, geometric_conj_bf, gaussian_conj,
conjugate_gauss_beams)
from .medium import Medium
from .utils import (refraction_angle, deviation, fresnel_coefficients,
brewster_angle, critical_angle, lens_makers_formula, mirror_formula,
lens_formula, hyperfocal_distance, transverse_magnification)
from .polarization import (jones_vector, stokes_vector, jones_2_stokes,
linear_polarizer, phase_retarder, half_wave_retarder,
quarter_wave_retarder, transmissive_filter, reflective_filter,
mueller_matrix, polarizing_beam_splitter)
PK ]ZZZN\�Q �Q sympy/physics/optics/gaussopt.py"""
Gaussian optics.
The module implements:
- Ray transfer matrices for geometrical and gaussian optics.
See RayTransferMatrix, GeometricRay and BeamParameter
- Conjugation relations for geometrical and gaussian optics.
See geometric_conj*, gauss_conj and conjugate_gauss_beams
The conventions for the distances are as follows:
focal distance
positive for convergent lenses
object distance
positive for real objects
image distance
positive for real images
"""
__all__ = [
'RayTransferMatrix',
'FreeSpace',
'FlatRefraction',
'CurvedRefraction',
'FlatMirror',
'CurvedMirror',
'ThinLens',
'GeometricRay',
'BeamParameter',
'waist2rayleigh',
'rayleigh2waist',
'geometric_conj_ab',
'geometric_conj_af',
'geometric_conj_bf',
'gaussian_conj',
'conjugate_gauss_beams',
]
from sympy.core.expr import Expr
from sympy.core.numbers import (I, pi)
from sympy.core.sympify import sympify
from sympy.functions.elementary.complexes import (im, re)
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.elementary.trigonometric import atan2
from sympy.matrices.dense import Matrix, MutableDenseMatrix
from sympy.polys.rationaltools import together
from sympy.utilities.misc import filldedent
###
# A, B, C, D matrices
###
class RayTransferMatrix(MutableDenseMatrix):
"""
Base class for a Ray Transfer Matrix.
It should be used if there is not already a more specific subclass mentioned
in See Also.
Parameters
==========
parameters :
A, B, C and D or 2x2 matrix (Matrix(2, 2, [A, B, C, D]))
Examples
========
>>> from sympy.physics.optics import RayTransferMatrix, ThinLens
>>> from sympy import Symbol, Matrix
>>> mat = RayTransferMatrix(1, 2, 3, 4)
>>> mat
Matrix([
[1, 2],
[3, 4]])
>>> RayTransferMatrix(Matrix([[1, 2], [3, 4]]))
Matrix([
[1, 2],
[3, 4]])
>>> mat.A
1
>>> f = Symbol('f')
>>> lens = ThinLens(f)
>>> lens
Matrix([
[ 1, 0],
[-1/f, 1]])
>>> lens.C
-1/f
See Also
========
GeometricRay, BeamParameter,
FreeSpace, FlatRefraction, CurvedRefraction,
FlatMirror, CurvedMirror, ThinLens
References
==========
.. [1] https://en.wikipedia.org/wiki/Ray_transfer_matrix_analysis
"""
def __new__(cls, *args):
if len(args) == 4:
temp = ((args[0], args[1]), (args[2], args[3]))
elif len(args) == 1 \
and isinstance(args[0], Matrix) \
and args[0].shape == (2, 2):
temp = args[0]
else:
raise ValueError(filldedent('''
Expecting 2x2 Matrix or the 4 elements of
the Matrix but got %s''' % str(args)))
return Matrix.__new__(cls, temp)
def __mul__(self, other):
if isinstance(other, RayTransferMatrix):
return RayTransferMatrix(Matrix(self)*Matrix(other))
elif isinstance(other, GeometricRay):
return GeometricRay(Matrix(self)*Matrix(other))
elif isinstance(other, BeamParameter):
temp = Matrix(self)*Matrix(((other.q,), (1,)))
q = (temp[0]/temp[1]).expand(complex=True)
return BeamParameter(other.wavelen,
together(re(q)),
z_r=together(im(q)))
else:
return Matrix.__mul__(self, other)
@property
def A(self):
"""
The A parameter of the Matrix.
Examples
========
>>> from sympy.physics.optics import RayTransferMatrix
>>> mat = RayTransferMatrix(1, 2, 3, 4)
>>> mat.A
1
"""
return self[0, 0]
@property
def B(self):
"""
The B parameter of the Matrix.
Examples
========
>>> from sympy.physics.optics import RayTransferMatrix
>>> mat = RayTransferMatrix(1, 2, 3, 4)
>>> mat.B
2
"""
return self[0, 1]
@property
def C(self):
"""
The C parameter of the Matrix.
Examples
========
>>> from sympy.physics.optics import RayTransferMatrix
>>> mat = RayTransferMatrix(1, 2, 3, 4)
>>> mat.C
3
"""
return self[1, 0]
@property
def D(self):
"""
The D parameter of the Matrix.
Examples
========
>>> from sympy.physics.optics import RayTransferMatrix
>>> mat = RayTransferMatrix(1, 2, 3, 4)
>>> mat.D
4
"""
return self[1, 1]
class FreeSpace(RayTransferMatrix):
"""
Ray Transfer Matrix for free space.
Parameters
==========
distance
See Also
========
RayTransferMatrix
Examples
========
>>> from sympy.physics.optics import FreeSpace
>>> from sympy import symbols
>>> d = symbols('d')
>>> FreeSpace(d)
Matrix([
[1, d],
[0, 1]])
"""
def __new__(cls, d):
return RayTransferMatrix.__new__(cls, 1, d, 0, 1)
class FlatRefraction(RayTransferMatrix):
"""
Ray Transfer Matrix for refraction.
Parameters
==========
n1 :
Refractive index of one medium.
n2 :
Refractive index of other medium.
See Also
========
RayTransferMatrix
Examples
========
>>> from sympy.physics.optics import FlatRefraction
>>> from sympy import symbols
>>> n1, n2 = symbols('n1 n2')
>>> FlatRefraction(n1, n2)
Matrix([
[1, 0],
[0, n1/n2]])
"""
def __new__(cls, n1, n2):
n1, n2 = map(sympify, (n1, n2))
return RayTransferMatrix.__new__(cls, 1, 0, 0, n1/n2)
class CurvedRefraction(RayTransferMatrix):
"""
Ray Transfer Matrix for refraction on curved interface.
Parameters
==========
R :
Radius of curvature (positive for concave).
n1 :
Refractive index of one medium.
n2 :
Refractive index of other medium.
See Also
========
RayTransferMatrix
Examples
========
>>> from sympy.physics.optics import CurvedRefraction
>>> from sympy import symbols
>>> R, n1, n2 = symbols('R n1 n2')
>>> CurvedRefraction(R, n1, n2)
Matrix([
[ 1, 0],
[(n1 - n2)/(R*n2), n1/n2]])
"""
def __new__(cls, R, n1, n2):
R, n1, n2 = map(sympify, (R, n1, n2))
return RayTransferMatrix.__new__(cls, 1, 0, (n1 - n2)/R/n2, n1/n2)
class FlatMirror(RayTransferMatrix):
"""
Ray Transfer Matrix for reflection.
See Also
========
RayTransferMatrix
Examples
========
>>> from sympy.physics.optics import FlatMirror
>>> FlatMirror()
Matrix([
[1, 0],
[0, 1]])
"""
def __new__(cls):
return RayTransferMatrix.__new__(cls, 1, 0, 0, 1)
class CurvedMirror(RayTransferMatrix):
"""
Ray Transfer Matrix for reflection from curved surface.
Parameters
==========
R : radius of curvature (positive for concave)
See Also
========
RayTransferMatrix
Examples
========
>>> from sympy.physics.optics import CurvedMirror
>>> from sympy import symbols
>>> R = symbols('R')
>>> CurvedMirror(R)
Matrix([
[ 1, 0],
[-2/R, 1]])
"""
def __new__(cls, R):
R = sympify(R)
return RayTransferMatrix.__new__(cls, 1, 0, -2/R, 1)
class ThinLens(RayTransferMatrix):
"""
Ray Transfer Matrix for a thin lens.
Parameters
==========
f :
The focal distance.
See Also
========
RayTransferMatrix
Examples
========
>>> from sympy.physics.optics import ThinLens
>>> from sympy import symbols
>>> f = symbols('f')
>>> ThinLens(f)
Matrix([
[ 1, 0],
[-1/f, 1]])
"""
def __new__(cls, f):
f = sympify(f)
return RayTransferMatrix.__new__(cls, 1, 0, -1/f, 1)
###
# Representation for geometric ray
###
class GeometricRay(MutableDenseMatrix):
"""
Representation for a geometric ray in the Ray Transfer Matrix formalism.
Parameters
==========
h : height, and
angle : angle, or
matrix : a 2x1 matrix (Matrix(2, 1, [height, angle]))
Examples
========
>>> from sympy.physics.optics import GeometricRay, FreeSpace
>>> from sympy import symbols, Matrix
>>> d, h, angle = symbols('d, h, angle')
>>> GeometricRay(h, angle)
Matrix([
[ h],
[angle]])
>>> FreeSpace(d)*GeometricRay(h, angle)
Matrix([
[angle*d + h],
[ angle]])
>>> GeometricRay( Matrix( ((h,), (angle,)) ) )
Matrix([
[ h],
[angle]])
See Also
========
RayTransferMatrix
"""
def __new__(cls, *args):
if len(args) == 1 and isinstance(args[0], Matrix) \
and args[0].shape == (2, 1):
temp = args[0]
elif len(args) == 2:
temp = ((args[0],), (args[1],))
else:
raise ValueError(filldedent('''
Expecting 2x1 Matrix or the 2 elements of
the Matrix but got %s''' % str(args)))
return Matrix.__new__(cls, temp)
@property
def height(self):
"""
The distance from the optical axis.
Examples
========
>>> from sympy.physics.optics import GeometricRay
>>> from sympy import symbols
>>> h, angle = symbols('h, angle')
>>> gRay = GeometricRay(h, angle)
>>> gRay.height
h
"""
return self[0]
@property
def angle(self):
"""
The angle with the optical axis.
Examples
========
>>> from sympy.physics.optics import GeometricRay
>>> from sympy import symbols
>>> h, angle = symbols('h, angle')
>>> gRay = GeometricRay(h, angle)
>>> gRay.angle
angle
"""
return self[1]
###
# Representation for gauss beam
###
class BeamParameter(Expr):
"""
Representation for a gaussian ray in the Ray Transfer Matrix formalism.
Parameters
==========
wavelen : the wavelength,
z : the distance to waist, and
w : the waist, or
z_r : the rayleigh range.
n : the refractive index of medium.
Examples
========
>>> from sympy.physics.optics import BeamParameter
>>> p = BeamParameter(530e-9, 1, w=1e-3)
>>> p.q
1 + 1.88679245283019*I*pi
>>> p.q.n()
1.0 + 5.92753330865999*I
>>> p.w_0.n()
0.00100000000000000
>>> p.z_r.n()
5.92753330865999
>>> from sympy.physics.optics import FreeSpace
>>> fs = FreeSpace(10)
>>> p1 = fs*p
>>> p.w.n()
0.00101413072159615
>>> p1.w.n()
0.00210803120913829
See Also
========
RayTransferMatrix
References
==========
.. [1] https://en.wikipedia.org/wiki/Complex_beam_parameter
.. [2] https://en.wikipedia.org/wiki/Gaussian_beam
"""
#TODO A class Complex may be implemented. The BeamParameter may
# subclass it. See:
# https://groups.google.com/d/topic/sympy/7XkU07NRBEs/discussion
def __new__(cls, wavelen, z, z_r=None, w=None, n=1):
wavelen = sympify(wavelen)
z = sympify(z)
n = sympify(n)
if z_r is not None and w is None:
z_r = sympify(z_r)
elif w is not None and z_r is None:
z_r = waist2rayleigh(sympify(w), wavelen, n)
elif z_r is None and w is None:
raise ValueError('Must specify one of w and z_r.')
return Expr.__new__(cls, wavelen, z, z_r, n)
@property
def wavelen(self):
return self.args[0]
@property
def z(self):
return self.args[1]
@property
def z_r(self):
return self.args[2]
@property
def n(self):
return self.args[3]
@property
def q(self):
"""
The complex parameter representing the beam.
Examples
========
>>> from sympy.physics.optics import BeamParameter
>>> p = BeamParameter(530e-9, 1, w=1e-3)
>>> p.q
1 + 1.88679245283019*I*pi
"""
return self.z + I*self.z_r
@property
def radius(self):
"""
The radius of curvature of the phase front.
Examples
========
>>> from sympy.physics.optics import BeamParameter
>>> p = BeamParameter(530e-9, 1, w=1e-3)
>>> p.radius
1 + 3.55998576005696*pi**2
"""
return self.z*(1 + (self.z_r/self.z)**2)
@property
def w(self):
"""
The radius of the beam w(z), at any position z along the beam.
The beam radius at `1/e^2` intensity (axial value).
See Also
========
w_0 :
The minimal radius of beam.
Examples
========
>>> from sympy.physics.optics import BeamParameter
>>> p = BeamParameter(530e-9, 1, w=1e-3)
>>> p.w
0.001*sqrt(0.2809/pi**2 + 1)
"""
return self.w_0*sqrt(1 + (self.z/self.z_r)**2)
@property
def w_0(self):
"""
The minimal radius of beam at `1/e^2` intensity (peak value).
See Also
========
w : the beam radius at `1/e^2` intensity (axial value).
Examples
========
>>> from sympy.physics.optics import BeamParameter
>>> p = BeamParameter(530e-9, 1, w=1e-3)
>>> p.w_0
0.00100000000000000
"""
return sqrt(self.z_r/(pi*self.n)*self.wavelen)
@property
def divergence(self):
"""
Half of the total angular spread.
Examples
========
>>> from sympy.physics.optics import BeamParameter
>>> p = BeamParameter(530e-9, 1, w=1e-3)
>>> p.divergence
0.00053/pi
"""
return self.wavelen/pi/self.w_0
@property
def gouy(self):
"""
The Gouy phase.
Examples
========
>>> from sympy.physics.optics import BeamParameter
>>> p = BeamParameter(530e-9, 1, w=1e-3)
>>> p.gouy
atan(0.53/pi)
"""
return atan2(self.z, self.z_r)
@property
def waist_approximation_limit(self):
"""
The minimal waist for which the gauss beam approximation is valid.
Explanation
===========
The gauss beam is a solution to the paraxial equation. For curvatures
that are too great it is not a valid approximation.
Examples
========
>>> from sympy.physics.optics import BeamParameter
>>> p = BeamParameter(530e-9, 1, w=1e-3)
>>> p.waist_approximation_limit
1.06e-6/pi
"""
return 2*self.wavelen/pi
###
# Utilities
###
def waist2rayleigh(w, wavelen, n=1):
"""
Calculate the rayleigh range from the waist of a gaussian beam.
See Also
========
rayleigh2waist, BeamParameter
Examples
========
>>> from sympy.physics.optics import waist2rayleigh
>>> from sympy import symbols
>>> w, wavelen = symbols('w wavelen')
>>> waist2rayleigh(w, wavelen)
pi*w**2/wavelen
"""
w, wavelen = map(sympify, (w, wavelen))
return w**2*n*pi/wavelen
def rayleigh2waist(z_r, wavelen):
"""Calculate the waist from the rayleigh range of a gaussian beam.
See Also
========
waist2rayleigh, BeamParameter
Examples
========
>>> from sympy.physics.optics import rayleigh2waist
>>> from sympy import symbols
>>> z_r, wavelen = symbols('z_r wavelen')
>>> rayleigh2waist(z_r, wavelen)
sqrt(wavelen*z_r)/sqrt(pi)
"""
z_r, wavelen = map(sympify, (z_r, wavelen))
return sqrt(z_r/pi*wavelen)
def geometric_conj_ab(a, b):
"""
Conjugation relation for geometrical beams under paraxial conditions.
Explanation
===========
Takes the distances to the optical element and returns the needed
focal distance.
See Also
========
geometric_conj_af, geometric_conj_bf
Examples
========
>>> from sympy.physics.optics import geometric_conj_ab
>>> from sympy import symbols
>>> a, b = symbols('a b')
>>> geometric_conj_ab(a, b)
a*b/(a + b)
"""
a, b = map(sympify, (a, b))
if a.is_infinite or b.is_infinite:
return a if b.is_infinite else b
else:
return a*b/(a + b)
def geometric_conj_af(a, f):
"""
Conjugation relation for geometrical beams under paraxial conditions.
Explanation
===========
Takes the object distance (for geometric_conj_af) or the image distance
(for geometric_conj_bf) to the optical element and the focal distance.
Then it returns the other distance needed for conjugation.
See Also
========
geometric_conj_ab
Examples
========
>>> from sympy.physics.optics.gaussopt import geometric_conj_af, geometric_conj_bf
>>> from sympy import symbols
>>> a, b, f = symbols('a b f')
>>> geometric_conj_af(a, f)
a*f/(a - f)
>>> geometric_conj_bf(b, f)
b*f/(b - f)
"""
a, f = map(sympify, (a, f))
return -geometric_conj_ab(a, -f)
geometric_conj_bf = geometric_conj_af
def gaussian_conj(s_in, z_r_in, f):
"""
Conjugation relation for gaussian beams.
Parameters
==========
s_in :
The distance to optical element from the waist.
z_r_in :
The rayleigh range of the incident beam.
f :
The focal length of the optical element.
Returns
=======
a tuple containing (s_out, z_r_out, m)
s_out :
The distance between the new waist and the optical element.
z_r_out :
The rayleigh range of the emergent beam.
m :
The ration between the new and the old waists.
Examples
========
>>> from sympy.physics.optics import gaussian_conj
>>> from sympy import symbols
>>> s_in, z_r_in, f = symbols('s_in z_r_in f')
>>> gaussian_conj(s_in, z_r_in, f)[0]
1/(-1/(s_in + z_r_in**2/(-f + s_in)) + 1/f)
>>> gaussian_conj(s_in, z_r_in, f)[1]
z_r_in/(1 - s_in**2/f**2 + z_r_in**2/f**2)
>>> gaussian_conj(s_in, z_r_in, f)[2]
1/sqrt(1 - s_in**2/f**2 + z_r_in**2/f**2)
"""
s_in, z_r_in, f = map(sympify, (s_in, z_r_in, f))
s_out = 1 / ( -1/(s_in + z_r_in**2/(s_in - f)) + 1/f )
m = 1/sqrt((1 - (s_in/f)**2) + (z_r_in/f)**2)
z_r_out = z_r_in / ((1 - (s_in/f)**2) + (z_r_in/f)**2)
return (s_out, z_r_out, m)
def conjugate_gauss_beams(wavelen, waist_in, waist_out, **kwargs):
"""
Find the optical setup conjugating the object/image waists.
Parameters
==========
wavelen :
The wavelength of the beam.
waist_in and waist_out :
The waists to be conjugated.
f :
The focal distance of the element used in the conjugation.
Returns
=======
a tuple containing (s_in, s_out, f)
s_in :
The distance before the optical element.
s_out :
The distance after the optical element.
f :
The focal distance of the optical element.
Examples
========
>>> from sympy.physics.optics import conjugate_gauss_beams
>>> from sympy import symbols, factor
>>> l, w_i, w_o, f = symbols('l w_i w_o f')
>>> conjugate_gauss_beams(l, w_i, w_o, f=f)[0]
f*(1 - sqrt(w_i**2/w_o**2 - pi**2*w_i**4/(f**2*l**2)))
>>> factor(conjugate_gauss_beams(l, w_i, w_o, f=f)[1])
f*w_o**2*(w_i**2/w_o**2 - sqrt(w_i**2/w_o**2 -
pi**2*w_i**4/(f**2*l**2)))/w_i**2
>>> conjugate_gauss_beams(l, w_i, w_o, f=f)[2]
f
"""
#TODO add the other possible arguments
wavelen, waist_in, waist_out = map(sympify, (wavelen, waist_in, waist_out))
m = waist_out / waist_in
z = waist2rayleigh(waist_in, wavelen)
if len(kwargs) != 1:
raise ValueError("The function expects only one named argument")
elif 'dist' in kwargs:
raise NotImplementedError(filldedent('''
Currently only focal length is supported as a parameter'''))
elif 'f' in kwargs:
f = sympify(kwargs['f'])
s_in = f * (1 - sqrt(1/m**2 - z**2/f**2))
s_out = gaussian_conj(s_in, z, f)[0]
elif 's_in' in kwargs:
raise NotImplementedError(filldedent('''
Currently only focal length is supported as a parameter'''))
else:
raise ValueError(filldedent('''
The functions expects the focal length as a named argument'''))
return (s_in, s_out, f)
#TODO
#def plot_beam():
# """Plot the beam radius as it propagates in space."""
# pass
#TODO
#def plot_beam_conjugation():
# """
# Plot the intersection of two beams.
#
# Represents the conjugation relation.
#
# See Also
# ========
#
# conjugate_gauss_beams
# """
# pass
PK ]ZZZ����� � sympy/physics/optics/medium.py"""
**Contains**
* Medium
"""
from sympy.physics.units import second, meter, kilogram, ampere
__all__ = ['Medium']
from sympy.core.basic import Basic
from sympy.core.symbol import Str
from sympy.core.sympify import _sympify
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.physics.units import speed_of_light, u0, e0
c = speed_of_light.convert_to(meter/second)
_e0mksa = e0.convert_to(ampere**2*second**4/(kilogram*meter**3))
_u0mksa = u0.convert_to(meter*kilogram/(ampere**2*second**2))
class Medium(Basic):
"""
This class represents an optical medium. The prime reason to implement this is
to facilitate refraction, Fermat's principle, etc.
Explanation
===========
An optical medium is a material through which electromagnetic waves propagate.
The permittivity and permeability of the medium define how electromagnetic
waves propagate in it.
Parameters
==========
name: string
The display name of the Medium.
permittivity: Sympifyable
Electric permittivity of the space.
permeability: Sympifyable
Magnetic permeability of the space.
n: Sympifyable
Index of refraction of the medium.
Examples
========
>>> from sympy.abc import epsilon, mu
>>> from sympy.physics.optics import Medium
>>> m1 = Medium('m1')
>>> m2 = Medium('m2', epsilon, mu)
>>> m1.intrinsic_impedance
149896229*pi*kilogram*meter**2/(1250000*ampere**2*second**3)
>>> m2.refractive_index
299792458*meter*sqrt(epsilon*mu)/second
References
==========
.. [1] https://en.wikipedia.org/wiki/Optical_medium
"""
def __new__(cls, name, permittivity=None, permeability=None, n=None):
if not isinstance(name, Str):
name = Str(name)
permittivity = _sympify(permittivity) if permittivity is not None else permittivity
permeability = _sympify(permeability) if permeability is not None else permeability
n = _sympify(n) if n is not None else n
if n is not None:
if permittivity is not None and permeability is None:
permeability = n**2/(c**2*permittivity)
return MediumPP(name, permittivity, permeability)
elif permeability is not None and permittivity is None:
permittivity = n**2/(c**2*permeability)
return MediumPP(name, permittivity, permeability)
elif permittivity is not None and permittivity is not None:
raise ValueError("Specifying all of permittivity, permeability, and n is not allowed")
else:
return MediumN(name, n)
elif permittivity is not None and permeability is not None:
return MediumPP(name, permittivity, permeability)
elif permittivity is None and permeability is None:
return MediumPP(name, _e0mksa, _u0mksa)
else:
raise ValueError("Arguments are underspecified. Either specify n or any two of permittivity, "
"permeability, and n")
@property
def name(self):
return self.args[0]
@property
def speed(self):
"""
Returns speed of the electromagnetic wave travelling in the medium.
Examples
========
>>> from sympy.physics.optics import Medium
>>> m = Medium('m')
>>> m.speed
299792458*meter/second
>>> m2 = Medium('m2', n=1)
>>> m.speed == m2.speed
True
"""
return c / self.n
@property
def refractive_index(self):
"""
Returns refractive index of the medium.
Examples
========
>>> from sympy.physics.optics import Medium
>>> m = Medium('m')
>>> m.refractive_index
1
"""
return (c/self.speed)
class MediumN(Medium):
"""
Represents an optical medium for which only the refractive index is known.
Useful for simple ray optics.
This class should never be instantiated directly.
Instead it should be instantiated indirectly by instantiating Medium with
only n specified.
Examples
========
>>> from sympy.physics.optics import Medium
>>> m = Medium('m', n=2)
>>> m
MediumN(Str('m'), 2)
"""
def __new__(cls, name, n):
obj = super(Medium, cls).__new__(cls, name, n)
return obj
@property
def n(self):
return self.args[1]
class MediumPP(Medium):
"""
Represents an optical medium for which the permittivity and permeability are known.
This class should never be instantiated directly. Instead it should be
instantiated indirectly by instantiating Medium with any two of
permittivity, permeability, and n specified, or by not specifying any
of permittivity, permeability, or n, in which case default values for
permittivity and permeability will be used.
Examples
========
>>> from sympy.physics.optics import Medium
>>> from sympy.abc import epsilon, mu
>>> m1 = Medium('m1', permittivity=epsilon, permeability=mu)
>>> m1
MediumPP(Str('m1'), epsilon, mu)
>>> m2 = Medium('m2')
>>> m2
MediumPP(Str('m2'), 625000*ampere**2*second**4/(22468879468420441*pi*kilogram*meter**3), pi*kilogram*meter/(2500000*ampere**2*second**2))
"""
def __new__(cls, name, permittivity, permeability):
obj = super(Medium, cls).__new__(cls, name, permittivity, permeability)
return obj
@property
def intrinsic_impedance(self):
"""
Returns intrinsic impedance of the medium.
Explanation
===========
The intrinsic impedance of a medium is the ratio of the
transverse components of the electric and magnetic fields
of the electromagnetic wave travelling in the medium.
In a region with no electrical conductivity it simplifies
to the square root of ratio of magnetic permeability to
electric permittivity.
Examples
========
>>> from sympy.physics.optics import Medium
>>> m = Medium('m')
>>> m.intrinsic_impedance
149896229*pi*kilogram*meter**2/(1250000*ampere**2*second**3)
"""
return sqrt(self.permeability / self.permittivity)
@property
def permittivity(self):
"""
Returns electric permittivity of the medium.
Examples
========
>>> from sympy.physics.optics import Medium
>>> m = Medium('m')
>>> m.permittivity
625000*ampere**2*second**4/(22468879468420441*pi*kilogram*meter**3)
"""
return self.args[1]
@property
def permeability(self):
"""
Returns magnetic permeability of the medium.
Examples
========
>>> from sympy.physics.optics import Medium
>>> m = Medium('m')
>>> m.permeability
pi*kilogram*meter/(2500000*ampere**2*second**2)
"""
return self.args[2]
@property
def n(self):
return c*sqrt(self.permittivity*self.permeability)
PK ]ZZZ#��S �S $ sympy/physics/optics/polarization.py#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
The module implements routines to model the polarization of optical fields
and can be used to calculate the effects of polarization optical elements on
the fields.
- Jones vectors.
- Stokes vectors.
- Jones matrices.
- Mueller matrices.
Examples
========
We calculate a generic Jones vector:
>>> from sympy import symbols, pprint, zeros, simplify
>>> from sympy.physics.optics.polarization import (jones_vector, stokes_vector,
... half_wave_retarder, polarizing_beam_splitter, jones_2_stokes)
>>> psi, chi, p, I0 = symbols("psi, chi, p, I0", real=True)
>>> x0 = jones_vector(psi, chi)
>>> pprint(x0, use_unicode=True)
⎡-ⅈ⋅sin(χ)⋅sin(ψ) + cos(χ)⋅cos(ψ)⎤
⎢ ⎥
⎣ⅈ⋅sin(χ)⋅cos(ψ) + sin(ψ)⋅cos(χ) ⎦
And the more general Stokes vector:
>>> s0 = stokes_vector(psi, chi, p, I0)
>>> pprint(s0, use_unicode=True)
⎡ I₀ ⎤
⎢ ⎥
⎢I₀⋅p⋅cos(2⋅χ)⋅cos(2⋅ψ)⎥
⎢ ⎥
⎢I₀⋅p⋅sin(2⋅ψ)⋅cos(2⋅χ)⎥
⎢ ⎥
⎣ I₀⋅p⋅sin(2⋅χ) ⎦
We calculate how the Jones vector is modified by a half-wave plate:
>>> alpha = symbols("alpha", real=True)
>>> HWP = half_wave_retarder(alpha)
>>> x1 = simplify(HWP*x0)
We calculate the very common operation of passing a beam through a half-wave
plate and then through a polarizing beam-splitter. We do this by putting this
Jones vector as the first entry of a two-Jones-vector state that is transformed
by a 4x4 Jones matrix modelling the polarizing beam-splitter to get the
transmitted and reflected Jones vectors:
>>> PBS = polarizing_beam_splitter()
>>> X1 = zeros(4, 1)
>>> X1[:2, :] = x1
>>> X2 = PBS*X1
>>> transmitted_port = X2[:2, :]
>>> reflected_port = X2[2:, :]
This allows us to calculate how the power in both ports depends on the initial
polarization:
>>> transmitted_power = jones_2_stokes(transmitted_port)[0]
>>> reflected_power = jones_2_stokes(reflected_port)[0]
>>> print(transmitted_power)
cos(-2*alpha + chi + psi)**2/2 + cos(2*alpha + chi - psi)**2/2
>>> print(reflected_power)
sin(-2*alpha + chi + psi)**2/2 + sin(2*alpha + chi - psi)**2/2
Please see the description of the individual functions for further
details and examples.
References
==========
.. [1] https://en.wikipedia.org/wiki/Jones_calculus
.. [2] https://en.wikipedia.org/wiki/Mueller_calculus
.. [3] https://en.wikipedia.org/wiki/Stokes_parameters
"""
from sympy.core.numbers import (I, pi)
from sympy.functions.elementary.complexes import (Abs, im, re)
from sympy.functions.elementary.exponential import exp
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.elementary.trigonometric import (cos, sin)
from sympy.matrices.dense import Matrix
from sympy.simplify.simplify import simplify
from sympy.physics.quantum import TensorProduct
def jones_vector(psi, chi):
"""A Jones vector corresponding to a polarization ellipse with `psi` tilt,
and `chi` circularity.
Parameters
==========
psi : numeric type or SymPy Symbol
The tilt of the polarization relative to the `x` axis.
chi : numeric type or SymPy Symbol
The angle adjacent to the mayor axis of the polarization ellipse.
Returns
=======
Matrix :
A Jones vector.
Examples
========
The axes on the Poincaré sphere.
>>> from sympy import pprint, symbols, pi
>>> from sympy.physics.optics.polarization import jones_vector
>>> psi, chi = symbols("psi, chi", real=True)
A general Jones vector.
>>> pprint(jones_vector(psi, chi), use_unicode=True)
⎡-ⅈ⋅sin(χ)⋅sin(ψ) + cos(χ)⋅cos(ψ)⎤
⎢ ⎥
⎣ⅈ⋅sin(χ)⋅cos(ψ) + sin(ψ)⋅cos(χ) ⎦
Horizontal polarization.
>>> pprint(jones_vector(0, 0), use_unicode=True)
⎡1⎤
⎢ ⎥
⎣0⎦
Vertical polarization.
>>> pprint(jones_vector(pi/2, 0), use_unicode=True)
⎡0⎤
⎢ ⎥
⎣1⎦
Diagonal polarization.
>>> pprint(jones_vector(pi/4, 0), use_unicode=True)
⎡√2⎤
⎢──⎥
⎢2 ⎥
⎢ ⎥
⎢√2⎥
⎢──⎥
⎣2 ⎦
Anti-diagonal polarization.
>>> pprint(jones_vector(-pi/4, 0), use_unicode=True)
⎡ √2 ⎤
⎢ ── ⎥
⎢ 2 ⎥
⎢ ⎥
⎢-√2 ⎥
⎢────⎥
⎣ 2 ⎦
Right-hand circular polarization.
>>> pprint(jones_vector(0, pi/4), use_unicode=True)
⎡ √2 ⎤
⎢ ── ⎥
⎢ 2 ⎥
⎢ ⎥
⎢√2⋅ⅈ⎥
⎢────⎥
⎣ 2 ⎦
Left-hand circular polarization.
>>> pprint(jones_vector(0, -pi/4), use_unicode=True)
⎡ √2 ⎤
⎢ ── ⎥
⎢ 2 ⎥
⎢ ⎥
⎢-√2⋅ⅈ ⎥
⎢──────⎥
⎣ 2 ⎦
"""
return Matrix([-I*sin(chi)*sin(psi) + cos(chi)*cos(psi),
I*sin(chi)*cos(psi) + sin(psi)*cos(chi)])
def stokes_vector(psi, chi, p=1, I=1):
"""A Stokes vector corresponding to a polarization ellipse with ``psi``
tilt, and ``chi`` circularity.
Parameters
==========
psi : numeric type or SymPy Symbol
The tilt of the polarization relative to the ``x`` axis.
chi : numeric type or SymPy Symbol
The angle adjacent to the mayor axis of the polarization ellipse.
p : numeric type or SymPy Symbol
The degree of polarization.
I : numeric type or SymPy Symbol
The intensity of the field.
Returns
=======
Matrix :
A Stokes vector.
Examples
========
The axes on the Poincaré sphere.
>>> from sympy import pprint, symbols, pi
>>> from sympy.physics.optics.polarization import stokes_vector
>>> psi, chi, p, I = symbols("psi, chi, p, I", real=True)
>>> pprint(stokes_vector(psi, chi, p, I), use_unicode=True)
⎡ I ⎤
⎢ ⎥
⎢I⋅p⋅cos(2⋅χ)⋅cos(2⋅ψ)⎥
⎢ ⎥
⎢I⋅p⋅sin(2⋅ψ)⋅cos(2⋅χ)⎥
⎢ ⎥
⎣ I⋅p⋅sin(2⋅χ) ⎦
Horizontal polarization
>>> pprint(stokes_vector(0, 0), use_unicode=True)
⎡1⎤
⎢ ⎥
⎢1⎥
⎢ ⎥
⎢0⎥
⎢ ⎥
⎣0⎦
Vertical polarization
>>> pprint(stokes_vector(pi/2, 0), use_unicode=True)
⎡1 ⎤
⎢ ⎥
⎢-1⎥
⎢ ⎥
⎢0 ⎥
⎢ ⎥
⎣0 ⎦
Diagonal polarization
>>> pprint(stokes_vector(pi/4, 0), use_unicode=True)
⎡1⎤
⎢ ⎥
⎢0⎥
⎢ ⎥
⎢1⎥
⎢ ⎥
⎣0⎦
Anti-diagonal polarization
>>> pprint(stokes_vector(-pi/4, 0), use_unicode=True)
⎡1 ⎤
⎢ ⎥
⎢0 ⎥
⎢ ⎥
⎢-1⎥
⎢ ⎥
⎣0 ⎦
Right-hand circular polarization
>>> pprint(stokes_vector(0, pi/4), use_unicode=True)
⎡1⎤
⎢ ⎥
⎢0⎥
⎢ ⎥
⎢0⎥
⎢ ⎥
⎣1⎦
Left-hand circular polarization
>>> pprint(stokes_vector(0, -pi/4), use_unicode=True)
⎡1 ⎤
⎢ ⎥
⎢0 ⎥
⎢ ⎥
⎢0 ⎥
⎢ ⎥
⎣-1⎦
Unpolarized light
>>> pprint(stokes_vector(0, 0, 0), use_unicode=True)
⎡1⎤
⎢ ⎥
⎢0⎥
⎢ ⎥
⎢0⎥
⎢ ⎥
⎣0⎦
"""
S0 = I
S1 = I*p*cos(2*psi)*cos(2*chi)
S2 = I*p*sin(2*psi)*cos(2*chi)
S3 = I*p*sin(2*chi)
return Matrix([S0, S1, S2, S3])
def jones_2_stokes(e):
"""Return the Stokes vector for a Jones vector ``e``.
Parameters
==========
e : SymPy Matrix
A Jones vector.
Returns
=======
SymPy Matrix
A Jones vector.
Examples
========
The axes on the Poincaré sphere.
>>> from sympy import pprint, pi
>>> from sympy.physics.optics.polarization import jones_vector
>>> from sympy.physics.optics.polarization import jones_2_stokes
>>> H = jones_vector(0, 0)
>>> V = jones_vector(pi/2, 0)
>>> D = jones_vector(pi/4, 0)
>>> A = jones_vector(-pi/4, 0)
>>> R = jones_vector(0, pi/4)
>>> L = jones_vector(0, -pi/4)
>>> pprint([jones_2_stokes(e) for e in [H, V, D, A, R, L]],
... use_unicode=True)
⎡⎡1⎤ ⎡1 ⎤ ⎡1⎤ ⎡1 ⎤ ⎡1⎤ ⎡1 ⎤⎤
⎢⎢ ⎥ ⎢ ⎥ ⎢ ⎥ ⎢ ⎥ ⎢ ⎥ ⎢ ⎥⎥
⎢⎢1⎥ ⎢-1⎥ ⎢0⎥ ⎢0 ⎥ ⎢0⎥ ⎢0 ⎥⎥
⎢⎢ ⎥, ⎢ ⎥, ⎢ ⎥, ⎢ ⎥, ⎢ ⎥, ⎢ ⎥⎥
⎢⎢0⎥ ⎢0 ⎥ ⎢1⎥ ⎢-1⎥ ⎢0⎥ ⎢0 ⎥⎥
⎢⎢ ⎥ ⎢ ⎥ ⎢ ⎥ ⎢ ⎥ ⎢ ⎥ ⎢ ⎥⎥
⎣⎣0⎦ ⎣0 ⎦ ⎣0⎦ ⎣0 ⎦ ⎣1⎦ ⎣-1⎦⎦
"""
ex, ey = e
return Matrix([Abs(ex)**2 + Abs(ey)**2,
Abs(ex)**2 - Abs(ey)**2,
2*re(ex*ey.conjugate()),
-2*im(ex*ey.conjugate())])
def linear_polarizer(theta=0):
"""A linear polarizer Jones matrix with transmission axis at
an angle ``theta``.
Parameters
==========
theta : numeric type or SymPy Symbol
The angle of the transmission axis relative to the horizontal plane.
Returns
=======
SymPy Matrix
A Jones matrix representing the polarizer.
Examples
========
A generic polarizer.
>>> from sympy import pprint, symbols
>>> from sympy.physics.optics.polarization import linear_polarizer
>>> theta = symbols("theta", real=True)
>>> J = linear_polarizer(theta)
>>> pprint(J, use_unicode=True)
⎡ 2 ⎤
⎢ cos (θ) sin(θ)⋅cos(θ)⎥
⎢ ⎥
⎢ 2 ⎥
⎣sin(θ)⋅cos(θ) sin (θ) ⎦
"""
M = Matrix([[cos(theta)**2, sin(theta)*cos(theta)],
[sin(theta)*cos(theta), sin(theta)**2]])
return M
def phase_retarder(theta=0, delta=0):
"""A phase retarder Jones matrix with retardance ``delta`` at angle ``theta``.
Parameters
==========
theta : numeric type or SymPy Symbol
The angle of the fast axis relative to the horizontal plane.
delta : numeric type or SymPy Symbol
The phase difference between the fast and slow axes of the
transmitted light.
Returns
=======
SymPy Matrix :
A Jones matrix representing the retarder.
Examples
========
A generic retarder.
>>> from sympy import pprint, symbols
>>> from sympy.physics.optics.polarization import phase_retarder
>>> theta, delta = symbols("theta, delta", real=True)
>>> R = phase_retarder(theta, delta)
>>> pprint(R, use_unicode=True)
⎡ -ⅈ⋅δ -ⅈ⋅δ ⎤
⎢ ───── ───── ⎥
⎢⎛ ⅈ⋅δ 2 2 ⎞ 2 ⎛ ⅈ⋅δ⎞ 2 ⎥
⎢⎝ℯ ⋅sin (θ) + cos (θ)⎠⋅ℯ ⎝1 - ℯ ⎠⋅ℯ ⋅sin(θ)⋅cos(θ)⎥
⎢ ⎥
⎢ -ⅈ⋅δ -ⅈ⋅δ ⎥
⎢ ───── ─────⎥
⎢⎛ ⅈ⋅δ⎞ 2 ⎛ ⅈ⋅δ 2 2 ⎞ 2 ⎥
⎣⎝1 - ℯ ⎠⋅ℯ ⋅sin(θ)⋅cos(θ) ⎝ℯ ⋅cos (θ) + sin (θ)⎠⋅ℯ ⎦
"""
R = Matrix([[cos(theta)**2 + exp(I*delta)*sin(theta)**2,
(1-exp(I*delta))*cos(theta)*sin(theta)],
[(1-exp(I*delta))*cos(theta)*sin(theta),
sin(theta)**2 + exp(I*delta)*cos(theta)**2]])
return R*exp(-I*delta/2)
def half_wave_retarder(theta):
"""A half-wave retarder Jones matrix at angle ``theta``.
Parameters
==========
theta : numeric type or SymPy Symbol
The angle of the fast axis relative to the horizontal plane.
Returns
=======
SymPy Matrix
A Jones matrix representing the retarder.
Examples
========
A generic half-wave plate.
>>> from sympy import pprint, symbols
>>> from sympy.physics.optics.polarization import half_wave_retarder
>>> theta= symbols("theta", real=True)
>>> HWP = half_wave_retarder(theta)
>>> pprint(HWP, use_unicode=True)
⎡ ⎛ 2 2 ⎞ ⎤
⎢-ⅈ⋅⎝- sin (θ) + cos (θ)⎠ -2⋅ⅈ⋅sin(θ)⋅cos(θ) ⎥
⎢ ⎥
⎢ ⎛ 2 2 ⎞⎥
⎣ -2⋅ⅈ⋅sin(θ)⋅cos(θ) -ⅈ⋅⎝sin (θ) - cos (θ)⎠⎦
"""
return phase_retarder(theta, pi)
def quarter_wave_retarder(theta):
"""A quarter-wave retarder Jones matrix at angle ``theta``.
Parameters
==========
theta : numeric type or SymPy Symbol
The angle of the fast axis relative to the horizontal plane.
Returns
=======
SymPy Matrix
A Jones matrix representing the retarder.
Examples
========
A generic quarter-wave plate.
>>> from sympy import pprint, symbols
>>> from sympy.physics.optics.polarization import quarter_wave_retarder
>>> theta= symbols("theta", real=True)
>>> QWP = quarter_wave_retarder(theta)
>>> pprint(QWP, use_unicode=True)
⎡ -ⅈ⋅π -ⅈ⋅π ⎤
⎢ ───── ───── ⎥
⎢⎛ 2 2 ⎞ 4 4 ⎥
⎢⎝ⅈ⋅sin (θ) + cos (θ)⎠⋅ℯ (1 - ⅈ)⋅ℯ ⋅sin(θ)⋅cos(θ)⎥
⎢ ⎥
⎢ -ⅈ⋅π -ⅈ⋅π ⎥
⎢ ───── ─────⎥
⎢ 4 ⎛ 2 2 ⎞ 4 ⎥
⎣(1 - ⅈ)⋅ℯ ⋅sin(θ)⋅cos(θ) ⎝sin (θ) + ⅈ⋅cos (θ)⎠⋅ℯ ⎦
"""
return phase_retarder(theta, pi/2)
def transmissive_filter(T):
"""An attenuator Jones matrix with transmittance ``T``.
Parameters
==========
T : numeric type or SymPy Symbol
The transmittance of the attenuator.
Returns
=======
SymPy Matrix
A Jones matrix representing the filter.
Examples
========
A generic filter.
>>> from sympy import pprint, symbols
>>> from sympy.physics.optics.polarization import transmissive_filter
>>> T = symbols("T", real=True)
>>> NDF = transmissive_filter(T)
>>> pprint(NDF, use_unicode=True)
⎡√T 0 ⎤
⎢ ⎥
⎣0 √T⎦
"""
return Matrix([[sqrt(T), 0], [0, sqrt(T)]])
def reflective_filter(R):
"""A reflective filter Jones matrix with reflectance ``R``.
Parameters
==========
R : numeric type or SymPy Symbol
The reflectance of the filter.
Returns
=======
SymPy Matrix
A Jones matrix representing the filter.
Examples
========
A generic filter.
>>> from sympy import pprint, symbols
>>> from sympy.physics.optics.polarization import reflective_filter
>>> R = symbols("R", real=True)
>>> pprint(reflective_filter(R), use_unicode=True)
⎡√R 0 ⎤
⎢ ⎥
⎣0 -√R⎦
"""
return Matrix([[sqrt(R), 0], [0, -sqrt(R)]])
def mueller_matrix(J):
"""The Mueller matrix corresponding to Jones matrix `J`.
Parameters
==========
J : SymPy Matrix
A Jones matrix.
Returns
=======
SymPy Matrix
The corresponding Mueller matrix.
Examples
========
Generic optical components.
>>> from sympy import pprint, symbols
>>> from sympy.physics.optics.polarization import (mueller_matrix,
... linear_polarizer, half_wave_retarder, quarter_wave_retarder)
>>> theta = symbols("theta", real=True)
A linear_polarizer
>>> pprint(mueller_matrix(linear_polarizer(theta)), use_unicode=True)
⎡ cos(2⋅θ) sin(2⋅θ) ⎤
⎢ 1/2 ──────── ──────── 0⎥
⎢ 2 2 ⎥
⎢ ⎥
⎢cos(2⋅θ) cos(4⋅θ) 1 sin(4⋅θ) ⎥
⎢──────── ──────── + ─ ──────── 0⎥
⎢ 2 4 4 4 ⎥
⎢ ⎥
⎢sin(2⋅θ) sin(4⋅θ) 1 cos(4⋅θ) ⎥
⎢──────── ──────── ─ - ──────── 0⎥
⎢ 2 4 4 4 ⎥
⎢ ⎥
⎣ 0 0 0 0⎦
A half-wave plate
>>> pprint(mueller_matrix(half_wave_retarder(theta)), use_unicode=True)
⎡1 0 0 0 ⎤
⎢ ⎥
⎢ 4 2 ⎥
⎢0 8⋅sin (θ) - 8⋅sin (θ) + 1 sin(4⋅θ) 0 ⎥
⎢ ⎥
⎢ 4 2 ⎥
⎢0 sin(4⋅θ) - 8⋅sin (θ) + 8⋅sin (θ) - 1 0 ⎥
⎢ ⎥
⎣0 0 0 -1⎦
A quarter-wave plate
>>> pprint(mueller_matrix(quarter_wave_retarder(theta)), use_unicode=True)
⎡1 0 0 0 ⎤
⎢ ⎥
⎢ cos(4⋅θ) 1 sin(4⋅θ) ⎥
⎢0 ──────── + ─ ──────── -sin(2⋅θ)⎥
⎢ 2 2 2 ⎥
⎢ ⎥
⎢ sin(4⋅θ) 1 cos(4⋅θ) ⎥
⎢0 ──────── ─ - ──────── cos(2⋅θ) ⎥
⎢ 2 2 2 ⎥
⎢ ⎥
⎣0 sin(2⋅θ) -cos(2⋅θ) 0 ⎦
"""
A = Matrix([[1, 0, 0, 1],
[1, 0, 0, -1],
[0, 1, 1, 0],
[0, -I, I, 0]])
return simplify(A*TensorProduct(J, J.conjugate())*A.inv())
def polarizing_beam_splitter(Tp=1, Rs=1, Ts=0, Rp=0, phia=0, phib=0):
r"""A polarizing beam splitter Jones matrix at angle `theta`.
Parameters
==========
J : SymPy Matrix
A Jones matrix.
Tp : numeric type or SymPy Symbol
The transmissivity of the P-polarized component.
Rs : numeric type or SymPy Symbol
The reflectivity of the S-polarized component.
Ts : numeric type or SymPy Symbol
The transmissivity of the S-polarized component.
Rp : numeric type or SymPy Symbol
The reflectivity of the P-polarized component.
phia : numeric type or SymPy Symbol
The phase difference between transmitted and reflected component for
output mode a.
phib : numeric type or SymPy Symbol
The phase difference between transmitted and reflected component for
output mode b.
Returns
=======
SymPy Matrix
A 4x4 matrix representing the PBS. This matrix acts on a 4x1 vector
whose first two entries are the Jones vector on one of the PBS ports,
and the last two entries the Jones vector on the other port.
Examples
========
Generic polarizing beam-splitter.
>>> from sympy import pprint, symbols
>>> from sympy.physics.optics.polarization import polarizing_beam_splitter
>>> Ts, Rs, Tp, Rp = symbols(r"Ts, Rs, Tp, Rp", positive=True)
>>> phia, phib = symbols("phi_a, phi_b", real=True)
>>> PBS = polarizing_beam_splitter(Tp, Rs, Ts, Rp, phia, phib)
>>> pprint(PBS, use_unicode=False)
[ ____ ____ ]
[ \/ Tp 0 I*\/ Rp 0 ]
[ ]
[ ____ ____ I*phi_a]
[ 0 \/ Ts 0 -I*\/ Rs *e ]
[ ]
[ ____ ____ ]
[I*\/ Rp 0 \/ Tp 0 ]
[ ]
[ ____ I*phi_b ____ ]
[ 0 -I*\/ Rs *e 0 \/ Ts ]
"""
PBS = Matrix([[sqrt(Tp), 0, I*sqrt(Rp), 0],
[0, sqrt(Ts), 0, -I*sqrt(Rs)*exp(I*phia)],
[I*sqrt(Rp), 0, sqrt(Tp), 0],
[0, -I*sqrt(Rs)*exp(I*phib), 0, sqrt(Ts)]])
return PBS
PK ]ZZZ@D��V �V sympy/physics/optics/utils.py"""
**Contains**
* refraction_angle
* fresnel_coefficients
* deviation
* brewster_angle
* critical_angle
* lens_makers_formula
* mirror_formula
* lens_formula
* hyperfocal_distance
* transverse_magnification
"""
__all__ = ['refraction_angle',
'deviation',
'fresnel_coefficients',
'brewster_angle',
'critical_angle',
'lens_makers_formula',
'mirror_formula',
'lens_formula',
'hyperfocal_distance',
'transverse_magnification'
]
from sympy.core.numbers import (Float, I, oo, pi, zoo)
from sympy.core.singleton import S
from sympy.core.symbol import Symbol
from sympy.core.sympify import sympify
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.elementary.trigonometric import (acos, asin, atan2, cos, sin, tan)
from sympy.matrices.dense import Matrix
from sympy.polys.polytools import cancel
from sympy.series.limits import Limit
from sympy.geometry.line import Ray3D
from sympy.geometry.util import intersection
from sympy.geometry.plane import Plane
from sympy.utilities.iterables import is_sequence
from .medium import Medium
def refractive_index_of_medium(medium):
"""
Helper function that returns refractive index, given a medium
"""
if isinstance(medium, Medium):
n = medium.refractive_index
else:
n = sympify(medium)
return n
def refraction_angle(incident, medium1, medium2, normal=None, plane=None):
"""
This function calculates transmitted vector after refraction at planar
surface. ``medium1`` and ``medium2`` can be ``Medium`` or any sympifiable object.
If ``incident`` is a number then treated as angle of incidence (in radians)
in which case refraction angle is returned.
If ``incident`` is an object of `Ray3D`, `normal` also has to be an instance
of `Ray3D` in order to get the output as a `Ray3D`. Please note that if
plane of separation is not provided and normal is an instance of `Ray3D`,
``normal`` will be assumed to be intersecting incident ray at the plane of
separation. This will not be the case when `normal` is a `Matrix` or
any other sequence.
If ``incident`` is an instance of `Ray3D` and `plane` has not been provided
and ``normal`` is not `Ray3D`, output will be a `Matrix`.
Parameters
==========
incident : Matrix, Ray3D, sequence or a number
Incident vector or angle of incidence
medium1 : sympy.physics.optics.medium.Medium or sympifiable
Medium 1 or its refractive index
medium2 : sympy.physics.optics.medium.Medium or sympifiable
Medium 2 or its refractive index
normal : Matrix, Ray3D, or sequence
Normal vector
plane : Plane
Plane of separation of the two media.
Returns
=======
Returns an angle of refraction or a refracted ray depending on inputs.
Examples
========
>>> from sympy.physics.optics import refraction_angle
>>> from sympy.geometry import Point3D, Ray3D, Plane
>>> from sympy.matrices import Matrix
>>> from sympy import symbols, pi
>>> n = Matrix([0, 0, 1])
>>> P = Plane(Point3D(0, 0, 0), normal_vector=[0, 0, 1])
>>> r1 = Ray3D(Point3D(-1, -1, 1), Point3D(0, 0, 0))
>>> refraction_angle(r1, 1, 1, n)
Matrix([
[ 1],
[ 1],
[-1]])
>>> refraction_angle(r1, 1, 1, plane=P)
Ray3D(Point3D(0, 0, 0), Point3D(1, 1, -1))
With different index of refraction of the two media
>>> n1, n2 = symbols('n1, n2')
>>> refraction_angle(r1, n1, n2, n)
Matrix([
[ n1/n2],
[ n1/n2],
[-sqrt(3)*sqrt(-2*n1**2/(3*n2**2) + 1)]])
>>> refraction_angle(r1, n1, n2, plane=P)
Ray3D(Point3D(0, 0, 0), Point3D(n1/n2, n1/n2, -sqrt(3)*sqrt(-2*n1**2/(3*n2**2) + 1)))
>>> round(refraction_angle(pi/6, 1.2, 1.5), 5)
0.41152
"""
n1 = refractive_index_of_medium(medium1)
n2 = refractive_index_of_medium(medium2)
# check if an incidence angle was supplied instead of a ray
try:
angle_of_incidence = float(incident)
except TypeError:
angle_of_incidence = None
try:
critical_angle_ = critical_angle(medium1, medium2)
except (ValueError, TypeError):
critical_angle_ = None
if angle_of_incidence is not None:
if normal is not None or plane is not None:
raise ValueError('Normal/plane not allowed if incident is an angle')
if not 0.0 <= angle_of_incidence < pi*0.5:
raise ValueError('Angle of incidence not in range [0:pi/2)')
if critical_angle_ and angle_of_incidence > critical_angle_:
raise ValueError('Ray undergoes total internal reflection')
return asin(n1*sin(angle_of_incidence)/n2)
# Treat the incident as ray below
# A flag to check whether to return Ray3D or not
return_ray = False
if plane is not None and normal is not None:
raise ValueError("Either plane or normal is acceptable.")
if not isinstance(incident, Matrix):
if is_sequence(incident):
_incident = Matrix(incident)
elif isinstance(incident, Ray3D):
_incident = Matrix(incident.direction_ratio)
else:
raise TypeError(
"incident should be a Matrix, Ray3D, or sequence")
else:
_incident = incident
# If plane is provided, get direction ratios of the normal
# to the plane from the plane else go with `normal` param.
if plane is not None:
if not isinstance(plane, Plane):
raise TypeError("plane should be an instance of geometry.plane.Plane")
# If we have the plane, we can get the intersection
# point of incident ray and the plane and thus return
# an instance of Ray3D.
if isinstance(incident, Ray3D):
return_ray = True
intersection_pt = plane.intersection(incident)[0]
_normal = Matrix(plane.normal_vector)
else:
if not isinstance(normal, Matrix):
if is_sequence(normal):
_normal = Matrix(normal)
elif isinstance(normal, Ray3D):
_normal = Matrix(normal.direction_ratio)
if isinstance(incident, Ray3D):
intersection_pt = intersection(incident, normal)
if len(intersection_pt) == 0:
raise ValueError(
"Normal isn't concurrent with the incident ray.")
else:
return_ray = True
intersection_pt = intersection_pt[0]
else:
raise TypeError(
"Normal should be a Matrix, Ray3D, or sequence")
else:
_normal = normal
eta = n1/n2 # Relative index of refraction
# Calculating magnitude of the vectors
mag_incident = sqrt(sum(i**2 for i in _incident))
mag_normal = sqrt(sum(i**2 for i in _normal))
# Converting vectors to unit vectors by dividing
# them with their magnitudes
_incident /= mag_incident
_normal /= mag_normal
c1 = -_incident.dot(_normal) # cos(angle_of_incidence)
cs2 = 1 - eta**2*(1 - c1**2) # cos(angle_of_refraction)**2
if cs2.is_negative: # This is the case of total internal reflection(TIR).
return S.Zero
drs = eta*_incident + (eta*c1 - sqrt(cs2))*_normal
# Multiplying unit vector by its magnitude
drs = drs*mag_incident
if not return_ray:
return drs
else:
return Ray3D(intersection_pt, direction_ratio=drs)
def fresnel_coefficients(angle_of_incidence, medium1, medium2):
"""
This function uses Fresnel equations to calculate reflection and
transmission coefficients. Those are obtained for both polarisations
when the electric field vector is in the plane of incidence (labelled 'p')
and when the electric field vector is perpendicular to the plane of
incidence (labelled 's'). There are four real coefficients unless the
incident ray reflects in total internal in which case there are two complex
ones. Angle of incidence is the angle between the incident ray and the
surface normal. ``medium1`` and ``medium2`` can be ``Medium`` or any
sympifiable object.
Parameters
==========
angle_of_incidence : sympifiable
medium1 : Medium or sympifiable
Medium 1 or its refractive index
medium2 : Medium or sympifiable
Medium 2 or its refractive index
Returns
=======
Returns a list with four real Fresnel coefficients:
[reflection p (TM), reflection s (TE),
transmission p (TM), transmission s (TE)]
If the ray is undergoes total internal reflection then returns a
list of two complex Fresnel coefficients:
[reflection p (TM), reflection s (TE)]
Examples
========
>>> from sympy.physics.optics import fresnel_coefficients
>>> fresnel_coefficients(0.3, 1, 2)
[0.317843553417859, -0.348645229818821,
0.658921776708929, 0.651354770181179]
>>> fresnel_coefficients(0.6, 2, 1)
[-0.235625382192159 - 0.971843958291041*I,
0.816477005968898 - 0.577377951366403*I]
References
==========
.. [1] https://en.wikipedia.org/wiki/Fresnel_equations
"""
if not 0 <= 2*angle_of_incidence < pi:
raise ValueError('Angle of incidence not in range [0:pi/2)')
n1 = refractive_index_of_medium(medium1)
n2 = refractive_index_of_medium(medium2)
angle_of_refraction = asin(n1*sin(angle_of_incidence)/n2)
try:
angle_of_total_internal_reflection_onset = critical_angle(n1, n2)
except ValueError:
angle_of_total_internal_reflection_onset = None
if angle_of_total_internal_reflection_onset is None or\
angle_of_total_internal_reflection_onset > angle_of_incidence:
R_s = -sin(angle_of_incidence - angle_of_refraction)\
/sin(angle_of_incidence + angle_of_refraction)
R_p = tan(angle_of_incidence - angle_of_refraction)\
/tan(angle_of_incidence + angle_of_refraction)
T_s = 2*sin(angle_of_refraction)*cos(angle_of_incidence)\
/sin(angle_of_incidence + angle_of_refraction)
T_p = 2*sin(angle_of_refraction)*cos(angle_of_incidence)\
/(sin(angle_of_incidence + angle_of_refraction)\
*cos(angle_of_incidence - angle_of_refraction))
return [R_p, R_s, T_p, T_s]
else:
n = n2/n1
R_s = cancel((cos(angle_of_incidence)-\
I*sqrt(sin(angle_of_incidence)**2 - n**2))\
/(cos(angle_of_incidence)+\
I*sqrt(sin(angle_of_incidence)**2 - n**2)))
R_p = cancel((n**2*cos(angle_of_incidence)-\
I*sqrt(sin(angle_of_incidence)**2 - n**2))\
/(n**2*cos(angle_of_incidence)+\
I*sqrt(sin(angle_of_incidence)**2 - n**2)))
return [R_p, R_s]
def deviation(incident, medium1, medium2, normal=None, plane=None):
"""
This function calculates the angle of deviation of a ray
due to refraction at planar surface.
Parameters
==========
incident : Matrix, Ray3D, sequence or float
Incident vector or angle of incidence
medium1 : sympy.physics.optics.medium.Medium or sympifiable
Medium 1 or its refractive index
medium2 : sympy.physics.optics.medium.Medium or sympifiable
Medium 2 or its refractive index
normal : Matrix, Ray3D, or sequence
Normal vector
plane : Plane
Plane of separation of the two media.
Returns angular deviation between incident and refracted rays
Examples
========
>>> from sympy.physics.optics import deviation
>>> from sympy.geometry import Point3D, Ray3D, Plane
>>> from sympy.matrices import Matrix
>>> from sympy import symbols
>>> n1, n2 = symbols('n1, n2')
>>> n = Matrix([0, 0, 1])
>>> P = Plane(Point3D(0, 0, 0), normal_vector=[0, 0, 1])
>>> r1 = Ray3D(Point3D(-1, -1, 1), Point3D(0, 0, 0))
>>> deviation(r1, 1, 1, n)
0
>>> deviation(r1, n1, n2, plane=P)
-acos(-sqrt(-2*n1**2/(3*n2**2) + 1)) + acos(-sqrt(3)/3)
>>> round(deviation(0.1, 1.2, 1.5), 5)
-0.02005
"""
refracted = refraction_angle(incident,
medium1,
medium2,
normal=normal,
plane=plane)
try:
angle_of_incidence = Float(incident)
except TypeError:
angle_of_incidence = None
if angle_of_incidence is not None:
return float(refracted) - angle_of_incidence
if refracted != 0:
if isinstance(refracted, Ray3D):
refracted = Matrix(refracted.direction_ratio)
if not isinstance(incident, Matrix):
if is_sequence(incident):
_incident = Matrix(incident)
elif isinstance(incident, Ray3D):
_incident = Matrix(incident.direction_ratio)
else:
raise TypeError(
"incident should be a Matrix, Ray3D, or sequence")
else:
_incident = incident
if plane is None:
if not isinstance(normal, Matrix):
if is_sequence(normal):
_normal = Matrix(normal)
elif isinstance(normal, Ray3D):
_normal = Matrix(normal.direction_ratio)
else:
raise TypeError(
"normal should be a Matrix, Ray3D, or sequence")
else:
_normal = normal
else:
_normal = Matrix(plane.normal_vector)
mag_incident = sqrt(sum(i**2 for i in _incident))
mag_normal = sqrt(sum(i**2 for i in _normal))
mag_refracted = sqrt(sum(i**2 for i in refracted))
_incident /= mag_incident
_normal /= mag_normal
refracted /= mag_refracted
i = acos(_incident.dot(_normal))
r = acos(refracted.dot(_normal))
return i - r
def brewster_angle(medium1, medium2):
"""
This function calculates the Brewster's angle of incidence to Medium 2 from
Medium 1 in radians.
Parameters
==========
medium 1 : Medium or sympifiable
Refractive index of Medium 1
medium 2 : Medium or sympifiable
Refractive index of Medium 1
Examples
========
>>> from sympy.physics.optics import brewster_angle
>>> brewster_angle(1, 1.33)
0.926093295503462
"""
n1 = refractive_index_of_medium(medium1)
n2 = refractive_index_of_medium(medium2)
return atan2(n2, n1)
def critical_angle(medium1, medium2):
"""
This function calculates the critical angle of incidence (marking the onset
of total internal) to Medium 2 from Medium 1 in radians.
Parameters
==========
medium 1 : Medium or sympifiable
Refractive index of Medium 1.
medium 2 : Medium or sympifiable
Refractive index of Medium 1.
Examples
========
>>> from sympy.physics.optics import critical_angle
>>> critical_angle(1.33, 1)
0.850908514477849
"""
n1 = refractive_index_of_medium(medium1)
n2 = refractive_index_of_medium(medium2)
if n2 > n1:
raise ValueError('Total internal reflection impossible for n1 < n2')
else:
return asin(n2/n1)
def lens_makers_formula(n_lens, n_surr, r1, r2, d=0):
"""
This function calculates focal length of a lens.
It follows cartesian sign convention.
Parameters
==========
n_lens : Medium or sympifiable
Index of refraction of lens.
n_surr : Medium or sympifiable
Index of reflection of surrounding.
r1 : sympifiable
Radius of curvature of first surface.
r2 : sympifiable
Radius of curvature of second surface.
d : sympifiable, optional
Thickness of lens, default value is 0.
Examples
========
>>> from sympy.physics.optics import lens_makers_formula
>>> from sympy import S
>>> lens_makers_formula(1.33, 1, 10, -10)
15.1515151515151
>>> lens_makers_formula(1.2, 1, 10, S.Infinity)
50.0000000000000
>>> lens_makers_formula(1.33, 1, 10, -10, d=1)
15.3418463277618
"""
if isinstance(n_lens, Medium):
n_lens = n_lens.refractive_index
else:
n_lens = sympify(n_lens)
if isinstance(n_surr, Medium):
n_surr = n_surr.refractive_index
else:
n_surr = sympify(n_surr)
d = sympify(d)
focal_length = 1/((n_lens - n_surr) / n_surr*(1/r1 - 1/r2 + (((n_lens - n_surr) * d) / (n_lens * r1 * r2))))
if focal_length == zoo:
return S.Infinity
return focal_length
def mirror_formula(focal_length=None, u=None, v=None):
"""
This function provides one of the three parameters
when two of them are supplied.
This is valid only for paraxial rays.
Parameters
==========
focal_length : sympifiable
Focal length of the mirror.
u : sympifiable
Distance of object from the pole on
the principal axis.
v : sympifiable
Distance of the image from the pole
on the principal axis.
Examples
========
>>> from sympy.physics.optics import mirror_formula
>>> from sympy.abc import f, u, v
>>> mirror_formula(focal_length=f, u=u)
f*u/(-f + u)
>>> mirror_formula(focal_length=f, v=v)
f*v/(-f + v)
>>> mirror_formula(u=u, v=v)
u*v/(u + v)
"""
if focal_length and u and v:
raise ValueError("Please provide only two parameters")
focal_length = sympify(focal_length)
u = sympify(u)
v = sympify(v)
if u is oo:
_u = Symbol('u')
if v is oo:
_v = Symbol('v')
if focal_length is oo:
_f = Symbol('f')
if focal_length is None:
if u is oo and v is oo:
return Limit(Limit(_v*_u/(_v + _u), _u, oo), _v, oo).doit()
if u is oo:
return Limit(v*_u/(v + _u), _u, oo).doit()
if v is oo:
return Limit(_v*u/(_v + u), _v, oo).doit()
return v*u/(v + u)
if u is None:
if v is oo and focal_length is oo:
return Limit(Limit(_v*_f/(_v - _f), _v, oo), _f, oo).doit()
if v is oo:
return Limit(_v*focal_length/(_v - focal_length), _v, oo).doit()
if focal_length is oo:
return Limit(v*_f/(v - _f), _f, oo).doit()
return v*focal_length/(v - focal_length)
if v is None:
if u is oo and focal_length is oo:
return Limit(Limit(_u*_f/(_u - _f), _u, oo), _f, oo).doit()
if u is oo:
return Limit(_u*focal_length/(_u - focal_length), _u, oo).doit()
if focal_length is oo:
return Limit(u*_f/(u - _f), _f, oo).doit()
return u*focal_length/(u - focal_length)
def lens_formula(focal_length=None, u=None, v=None):
"""
This function provides one of the three parameters
when two of them are supplied.
This is valid only for paraxial rays.
Parameters
==========
focal_length : sympifiable
Focal length of the mirror.
u : sympifiable
Distance of object from the optical center on
the principal axis.
v : sympifiable
Distance of the image from the optical center
on the principal axis.
Examples
========
>>> from sympy.physics.optics import lens_formula
>>> from sympy.abc import f, u, v
>>> lens_formula(focal_length=f, u=u)
f*u/(f + u)
>>> lens_formula(focal_length=f, v=v)
f*v/(f - v)
>>> lens_formula(u=u, v=v)
u*v/(u - v)
"""
if focal_length and u and v:
raise ValueError("Please provide only two parameters")
focal_length = sympify(focal_length)
u = sympify(u)
v = sympify(v)
if u is oo:
_u = Symbol('u')
if v is oo:
_v = Symbol('v')
if focal_length is oo:
_f = Symbol('f')
if focal_length is None:
if u is oo and v is oo:
return Limit(Limit(_v*_u/(_u - _v), _u, oo), _v, oo).doit()
if u is oo:
return Limit(v*_u/(_u - v), _u, oo).doit()
if v is oo:
return Limit(_v*u/(u - _v), _v, oo).doit()
return v*u/(u - v)
if u is None:
if v is oo and focal_length is oo:
return Limit(Limit(_v*_f/(_f - _v), _v, oo), _f, oo).doit()
if v is oo:
return Limit(_v*focal_length/(focal_length - _v), _v, oo).doit()
if focal_length is oo:
return Limit(v*_f/(_f - v), _f, oo).doit()
return v*focal_length/(focal_length - v)
if v is None:
if u is oo and focal_length is oo:
return Limit(Limit(_u*_f/(_u + _f), _u, oo), _f, oo).doit()
if u is oo:
return Limit(_u*focal_length/(_u + focal_length), _u, oo).doit()
if focal_length is oo:
return Limit(u*_f/(u + _f), _f, oo).doit()
return u*focal_length/(u + focal_length)
def hyperfocal_distance(f, N, c):
"""
Parameters
==========
f: sympifiable
Focal length of a given lens.
N: sympifiable
F-number of a given lens.
c: sympifiable
Circle of Confusion (CoC) of a given image format.
Example
=======
>>> from sympy.physics.optics import hyperfocal_distance
>>> round(hyperfocal_distance(f = 0.5, N = 8, c = 0.0033), 2)
9.47
"""
f = sympify(f)
N = sympify(N)
c = sympify(c)
return (1/(N * c))*(f**2)
def transverse_magnification(si, so):
"""
Calculates the transverse magnification upon reflection in a mirror,
which is the ratio of the image size to the object size.
Parameters
==========
so: sympifiable
Lens-object distance.
si: sympifiable
Lens-image distance.
Example
=======
>>> from sympy.physics.optics import transverse_magnification
>>> transverse_magnification(30, 15)
-2
"""
si = sympify(si)
so = sympify(so)
return (-(si/so))
PK ]ZZZ����:' :' sympy/physics/optics/waves.py"""
This module has all the classes and functions related to waves in optics.
**Contains**
* TWave
"""
__all__ = ['TWave']
from sympy.core.basic import Basic
from sympy.core.expr import Expr
from sympy.core.function import Derivative, Function
from sympy.core.numbers import (Number, pi, I)
from sympy.core.singleton import S
from sympy.core.symbol import (Symbol, symbols)
from sympy.core.sympify import _sympify, sympify
from sympy.functions.elementary.exponential import exp
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.elementary.trigonometric import (atan2, cos, sin)
from sympy.physics.units import speed_of_light, meter, second
c = speed_of_light.convert_to(meter/second)
class TWave(Expr):
r"""
This is a simple transverse sine wave travelling in a one-dimensional space.
Basic properties are required at the time of creation of the object,
but they can be changed later with respective methods provided.
Explanation
===========
It is represented as :math:`A \times cos(k*x - \omega \times t + \phi )`,
where :math:`A` is the amplitude, :math:`\omega` is the angular frequency,
:math:`k` is the wavenumber (spatial frequency), :math:`x` is a spatial variable
to represent the position on the dimension on which the wave propagates,
and :math:`\phi` is the phase angle of the wave.
Arguments
=========
amplitude : Sympifyable
Amplitude of the wave.
frequency : Sympifyable
Frequency of the wave.
phase : Sympifyable
Phase angle of the wave.
time_period : Sympifyable
Time period of the wave.
n : Sympifyable
Refractive index of the medium.
Raises
=======
ValueError : When neither frequency nor time period is provided
or they are not consistent.
TypeError : When anything other than TWave objects is added.
Examples
========
>>> from sympy import symbols
>>> from sympy.physics.optics import TWave
>>> A1, phi1, A2, phi2, f = symbols('A1, phi1, A2, phi2, f')
>>> w1 = TWave(A1, f, phi1)
>>> w2 = TWave(A2, f, phi2)
>>> w3 = w1 + w2 # Superposition of two waves
>>> w3
TWave(sqrt(A1**2 + 2*A1*A2*cos(phi1 - phi2) + A2**2), f,
atan2(A1*sin(phi1) + A2*sin(phi2), A1*cos(phi1) + A2*cos(phi2)), 1/f, n)
>>> w3.amplitude
sqrt(A1**2 + 2*A1*A2*cos(phi1 - phi2) + A2**2)
>>> w3.phase
atan2(A1*sin(phi1) + A2*sin(phi2), A1*cos(phi1) + A2*cos(phi2))
>>> w3.speed
299792458*meter/(second*n)
>>> w3.angular_velocity
2*pi*f
"""
def __new__(
cls,
amplitude,
frequency=None,
phase=S.Zero,
time_period=None,
n=Symbol('n')):
if time_period is not None:
time_period = _sympify(time_period)
_frequency = S.One/time_period
if frequency is not None:
frequency = _sympify(frequency)
_time_period = S.One/frequency
if time_period is not None:
if frequency != S.One/time_period:
raise ValueError("frequency and time_period should be consistent.")
if frequency is None and time_period is None:
raise ValueError("Either frequency or time period is needed.")
if frequency is None:
frequency = _frequency
if time_period is None:
time_period = _time_period
amplitude = _sympify(amplitude)
phase = _sympify(phase)
n = sympify(n)
obj = Basic.__new__(cls, amplitude, frequency, phase, time_period, n)
return obj
@property
def amplitude(self):
"""
Returns the amplitude of the wave.
Examples
========
>>> from sympy import symbols
>>> from sympy.physics.optics import TWave
>>> A, phi, f = symbols('A, phi, f')
>>> w = TWave(A, f, phi)
>>> w.amplitude
A
"""
return self.args[0]
@property
def frequency(self):
"""
Returns the frequency of the wave,
in cycles per second.
Examples
========
>>> from sympy import symbols
>>> from sympy.physics.optics import TWave
>>> A, phi, f = symbols('A, phi, f')
>>> w = TWave(A, f, phi)
>>> w.frequency
f
"""
return self.args[1]
@property
def phase(self):
"""
Returns the phase angle of the wave,
in radians.
Examples
========
>>> from sympy import symbols
>>> from sympy.physics.optics import TWave
>>> A, phi, f = symbols('A, phi, f')
>>> w = TWave(A, f, phi)
>>> w.phase
phi
"""
return self.args[2]
@property
def time_period(self):
"""
Returns the temporal period of the wave,
in seconds per cycle.
Examples
========
>>> from sympy import symbols
>>> from sympy.physics.optics import TWave
>>> A, phi, f = symbols('A, phi, f')
>>> w = TWave(A, f, phi)
>>> w.time_period
1/f
"""
return self.args[3]
@property
def n(self):
"""
Returns the refractive index of the medium
"""
return self.args[4]
@property
def wavelength(self):
"""
Returns the wavelength (spatial period) of the wave,
in meters per cycle.
It depends on the medium of the wave.
Examples
========
>>> from sympy import symbols
>>> from sympy.physics.optics import TWave
>>> A, phi, f = symbols('A, phi, f')
>>> w = TWave(A, f, phi)
>>> w.wavelength
299792458*meter/(second*f*n)
"""
return c/(self.frequency*self.n)
@property
def speed(self):
"""
Returns the propagation speed of the wave,
in meters per second.
It is dependent on the propagation medium.
Examples
========
>>> from sympy import symbols
>>> from sympy.physics.optics import TWave
>>> A, phi, f = symbols('A, phi, f')
>>> w = TWave(A, f, phi)
>>> w.speed
299792458*meter/(second*n)
"""
return self.wavelength*self.frequency
@property
def angular_velocity(self):
"""
Returns the angular velocity of the wave,
in radians per second.
Examples
========
>>> from sympy import symbols
>>> from sympy.physics.optics import TWave
>>> A, phi, f = symbols('A, phi, f')
>>> w = TWave(A, f, phi)
>>> w.angular_velocity
2*pi*f
"""
return 2*pi*self.frequency
@property
def wavenumber(self):
"""
Returns the wavenumber of the wave,
in radians per meter.
Examples
========
>>> from sympy import symbols
>>> from sympy.physics.optics import TWave
>>> A, phi, f = symbols('A, phi, f')
>>> w = TWave(A, f, phi)
>>> w.wavenumber
pi*second*f*n/(149896229*meter)
"""
return 2*pi/self.wavelength
def __str__(self):
"""String representation of a TWave."""
from sympy.printing import sstr
return type(self).__name__ + sstr(self.args)
__repr__ = __str__
def __add__(self, other):
"""
Addition of two waves will result in their superposition.
The type of interference will depend on their phase angles.
"""
if isinstance(other, TWave):
if self.frequency == other.frequency and self.wavelength == other.wavelength:
return TWave(sqrt(self.amplitude**2 + other.amplitude**2 + 2 *
self.amplitude*other.amplitude*cos(
self.phase - other.phase)),
self.frequency,
atan2(self.amplitude*sin(self.phase)
+ other.amplitude*sin(other.phase),
self.amplitude*cos(self.phase)
+ other.amplitude*cos(other.phase))
)
else:
raise NotImplementedError("Interference of waves with different frequencies"
" has not been implemented.")
else:
raise TypeError(type(other).__name__ + " and TWave objects cannot be added.")
def __mul__(self, other):
"""
Multiplying a wave by a scalar rescales the amplitude of the wave.
"""
other = sympify(other)
if isinstance(other, Number):
return TWave(self.amplitude*other, *self.args[1:])
else:
raise TypeError(type(other).__name__ + " and TWave objects cannot be multiplied.")
def __sub__(self, other):
return self.__add__(-1*other)
def __neg__(self):
return self.__mul__(-1)
def __radd__(self, other):
return self.__add__(other)
def __rmul__(self, other):
return self.__mul__(other)
def __rsub__(self, other):
return (-self).__radd__(other)
def _eval_rewrite_as_sin(self, *args, **kwargs):
return self.amplitude*sin(self.wavenumber*Symbol('x')
- self.angular_velocity*Symbol('t') + self.phase + pi/2, evaluate=False)
def _eval_rewrite_as_cos(self, *args, **kwargs):
return self.amplitude*cos(self.wavenumber*Symbol('x')
- self.angular_velocity*Symbol('t') + self.phase)
def _eval_rewrite_as_pde(self, *args, **kwargs):
mu, epsilon, x, t = symbols('mu, epsilon, x, t')
E = Function('E')
return Derivative(E(x, t), x, 2) + mu*epsilon*Derivative(E(x, t), t, 2)
def _eval_rewrite_as_exp(self, *args, **kwargs):
return self.amplitude*exp(I*(self.wavenumber*Symbol('x')
- self.angular_velocity*Symbol('t') + self.phase))
PK ]ZZZb���� � ! sympy/physics/quantum/__init__.py# Names exposed by 'from sympy.physics.quantum import *'
__all__ = [
'AntiCommutator',
'qapply',
'Commutator',
'Dagger',
'HilbertSpaceError', 'HilbertSpace', 'TensorProductHilbertSpace',
'TensorPowerHilbertSpace', 'DirectSumHilbertSpace', 'ComplexSpace', 'L2',
'FockSpace',
'InnerProduct',
'Operator', 'HermitianOperator', 'UnitaryOperator', 'IdentityOperator',
'OuterProduct', 'DifferentialOperator',
'represent', 'rep_innerproduct', 'rep_expectation', 'integrate_result',
'get_basis', 'enumerate_states',
'KetBase', 'BraBase', 'StateBase', 'State', 'Ket', 'Bra', 'TimeDepState',
'TimeDepBra', 'TimeDepKet', 'OrthogonalKet', 'OrthogonalBra',
'OrthogonalState', 'Wavefunction',
'TensorProduct', 'tensor_product_simp',
'hbar', 'HBar',
]
from .anticommutator import AntiCommutator
from .qapply import qapply
from .commutator import Commutator
from .dagger import Dagger
from .hilbert import (HilbertSpaceError, HilbertSpace,
TensorProductHilbertSpace, TensorPowerHilbertSpace,
DirectSumHilbertSpace, ComplexSpace, L2, FockSpace)
from .innerproduct import InnerProduct
from .operator import (Operator, HermitianOperator, UnitaryOperator,
IdentityOperator, OuterProduct, DifferentialOperator)
from .represent import (represent, rep_innerproduct, rep_expectation,
integrate_result, get_basis, enumerate_states)
from .state import (KetBase, BraBase, StateBase, State, Ket, Bra,
TimeDepState, TimeDepBra, TimeDepKet, OrthogonalKet,
OrthogonalBra, OrthogonalState, Wavefunction)
from .tensorproduct import TensorProduct, tensor_product_simp
from .constants import hbar, HBar
PK ]ZZZZ? (^ ^ ' sympy/physics/quantum/anticommutator.py"""The anti-commutator: ``{A,B} = A*B + B*A``."""
from sympy.core.expr import Expr
from sympy.core.mul import Mul
from sympy.core.numbers import Integer
from sympy.core.singleton import S
from sympy.printing.pretty.stringpict import prettyForm
from sympy.physics.quantum.operator import Operator
from sympy.physics.quantum.dagger import Dagger
__all__ = [
'AntiCommutator'
]
#-----------------------------------------------------------------------------
# Anti-commutator
#-----------------------------------------------------------------------------
class AntiCommutator(Expr):
"""The standard anticommutator, in an unevaluated state.
Explanation
===========
Evaluating an anticommutator is defined [1]_ as: ``{A, B} = A*B + B*A``.
This class returns the anticommutator in an unevaluated form. To evaluate
the anticommutator, use the ``.doit()`` method.
Canonical ordering of an anticommutator is ``{A, B}`` for ``A < B``. The
arguments of the anticommutator are put into canonical order using
``__cmp__``. If ``B < A``, then ``{A, B}`` is returned as ``{B, A}``.
Parameters
==========
A : Expr
The first argument of the anticommutator {A,B}.
B : Expr
The second argument of the anticommutator {A,B}.
Examples
========
>>> from sympy import symbols
>>> from sympy.physics.quantum import AntiCommutator
>>> from sympy.physics.quantum import Operator, Dagger
>>> x, y = symbols('x,y')
>>> A = Operator('A')
>>> B = Operator('B')
Create an anticommutator and use ``doit()`` to multiply them out.
>>> ac = AntiCommutator(A,B); ac
{A,B}
>>> ac.doit()
A*B + B*A
The commutator orders it arguments in canonical order:
>>> ac = AntiCommutator(B,A); ac
{A,B}
Commutative constants are factored out:
>>> AntiCommutator(3*x*A,x*y*B)
3*x**2*y*{A,B}
Adjoint operations applied to the anticommutator are properly applied to
the arguments:
>>> Dagger(AntiCommutator(A,B))
{Dagger(A),Dagger(B)}
References
==========
.. [1] https://en.wikipedia.org/wiki/Commutator
"""
is_commutative = False
def __new__(cls, A, B):
r = cls.eval(A, B)
if r is not None:
return r
obj = Expr.__new__(cls, A, B)
return obj
@classmethod
def eval(cls, a, b):
if not (a and b):
return S.Zero
if a == b:
return Integer(2)*a**2
if a.is_commutative or b.is_commutative:
return Integer(2)*a*b
# [xA,yB] -> xy*[A,B]
ca, nca = a.args_cnc()
cb, ncb = b.args_cnc()
c_part = ca + cb
if c_part:
return Mul(Mul(*c_part), cls(Mul._from_args(nca), Mul._from_args(ncb)))
# Canonical ordering of arguments
#The Commutator [A,B] is on canonical form if A < B.
if a.compare(b) == 1:
return cls(b, a)
def doit(self, **hints):
""" Evaluate anticommutator """
A = self.args[0]
B = self.args[1]
if isinstance(A, Operator) and isinstance(B, Operator):
try:
comm = A._eval_anticommutator(B, **hints)
except NotImplementedError:
try:
comm = B._eval_anticommutator(A, **hints)
except NotImplementedError:
comm = None
if comm is not None:
return comm.doit(**hints)
return (A*B + B*A).doit(**hints)
def _eval_adjoint(self):
return AntiCommutator(Dagger(self.args[0]), Dagger(self.args[1]))
def _sympyrepr(self, printer, *args):
return "%s(%s,%s)" % (
self.__class__.__name__, printer._print(
self.args[0]), printer._print(self.args[1])
)
def _sympystr(self, printer, *args):
return "{%s,%s}" % (
printer._print(self.args[0]), printer._print(self.args[1]))
def _pretty(self, printer, *args):
pform = printer._print(self.args[0], *args)
pform = prettyForm(*pform.right(prettyForm(',')))
pform = prettyForm(*pform.right(printer._print(self.args[1], *args)))
pform = prettyForm(*pform.parens(left='{', right='}'))
return pform
def _latex(self, printer, *args):
return "\\left\\{%s,%s\\right\\}" % tuple([
printer._print(arg, *args) for arg in self.args])
PK ]ZZZpl�� � sympy/physics/quantum/boson.py"""Bosonic quantum operators."""
from sympy.core.mul import Mul
from sympy.core.numbers import Integer
from sympy.core.singleton import S
from sympy.functions.elementary.complexes import conjugate
from sympy.functions.elementary.exponential import exp
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.physics.quantum import Operator
from sympy.physics.quantum import HilbertSpace, FockSpace, Ket, Bra, IdentityOperator
from sympy.functions.special.tensor_functions import KroneckerDelta
__all__ = [
'BosonOp',
'BosonFockKet',
'BosonFockBra',
'BosonCoherentKet',
'BosonCoherentBra'
]
class BosonOp(Operator):
"""A bosonic operator that satisfies [a, Dagger(a)] == 1.
Parameters
==========
name : str
A string that labels the bosonic mode.
annihilation : bool
A bool that indicates if the bosonic operator is an annihilation (True,
default value) or creation operator (False)
Examples
========
>>> from sympy.physics.quantum import Dagger, Commutator
>>> from sympy.physics.quantum.boson import BosonOp
>>> a = BosonOp("a")
>>> Commutator(a, Dagger(a)).doit()
1
"""
@property
def name(self):
return self.args[0]
@property
def is_annihilation(self):
return bool(self.args[1])
@classmethod
def default_args(self):
return ("a", True)
def __new__(cls, *args, **hints):
if not len(args) in [1, 2]:
raise ValueError('1 or 2 parameters expected, got %s' % args)
if len(args) == 1:
args = (args[0], S.One)
if len(args) == 2:
args = (args[0], Integer(args[1]))
return Operator.__new__(cls, *args)
def _eval_commutator_BosonOp(self, other, **hints):
if self.name == other.name:
# [a^\dagger, a] = -1
if not self.is_annihilation and other.is_annihilation:
return S.NegativeOne
elif 'independent' in hints and hints['independent']:
# [a, b] = 0
return S.Zero
return None
def _eval_commutator_FermionOp(self, other, **hints):
return S.Zero
def _eval_anticommutator_BosonOp(self, other, **hints):
if 'independent' in hints and hints['independent']:
# {a, b} = 2 * a * b, because [a, b] = 0
return 2 * self * other
return None
def _eval_adjoint(self):
return BosonOp(str(self.name), not self.is_annihilation)
def __mul__(self, other):
if other == IdentityOperator(2):
return self
if isinstance(other, Mul):
args1 = tuple(arg for arg in other.args if arg.is_commutative)
args2 = tuple(arg for arg in other.args if not arg.is_commutative)
x = self
for y in args2:
x = x * y
return Mul(*args1) * x
return Mul(self, other)
def _print_contents_latex(self, printer, *args):
if self.is_annihilation:
return r'{%s}' % str(self.name)
else:
return r'{{%s}^\dagger}' % str(self.name)
def _print_contents(self, printer, *args):
if self.is_annihilation:
return r'%s' % str(self.name)
else:
return r'Dagger(%s)' % str(self.name)
def _print_contents_pretty(self, printer, *args):
from sympy.printing.pretty.stringpict import prettyForm
pform = printer._print(self.args[0], *args)
if self.is_annihilation:
return pform
else:
return pform**prettyForm('\N{DAGGER}')
class BosonFockKet(Ket):
"""Fock state ket for a bosonic mode.
Parameters
==========
n : Number
The Fock state number.
"""
def __new__(cls, n):
return Ket.__new__(cls, n)
@property
def n(self):
return self.label[0]
@classmethod
def dual_class(self):
return BosonFockBra
@classmethod
def _eval_hilbert_space(cls, label):
return FockSpace()
def _eval_innerproduct_BosonFockBra(self, bra, **hints):
return KroneckerDelta(self.n, bra.n)
def _apply_from_right_to_BosonOp(self, op, **options):
if op.is_annihilation:
return sqrt(self.n) * BosonFockKet(self.n - 1)
else:
return sqrt(self.n + 1) * BosonFockKet(self.n + 1)
class BosonFockBra(Bra):
"""Fock state bra for a bosonic mode.
Parameters
==========
n : Number
The Fock state number.
"""
def __new__(cls, n):
return Bra.__new__(cls, n)
@property
def n(self):
return self.label[0]
@classmethod
def dual_class(self):
return BosonFockKet
@classmethod
def _eval_hilbert_space(cls, label):
return FockSpace()
class BosonCoherentKet(Ket):
"""Coherent state ket for a bosonic mode.
Parameters
==========
alpha : Number, Symbol
The complex amplitude of the coherent state.
"""
def __new__(cls, alpha):
return Ket.__new__(cls, alpha)
@property
def alpha(self):
return self.label[0]
@classmethod
def dual_class(self):
return BosonCoherentBra
@classmethod
def _eval_hilbert_space(cls, label):
return HilbertSpace()
def _eval_innerproduct_BosonCoherentBra(self, bra, **hints):
if self.alpha == bra.alpha:
return S.One
else:
return exp(-(abs(self.alpha)**2 + abs(bra.alpha)**2 - 2 * conjugate(bra.alpha) * self.alpha)/2)
def _apply_from_right_to_BosonOp(self, op, **options):
if op.is_annihilation:
return self.alpha * self
else:
return None
class BosonCoherentBra(Bra):
"""Coherent state bra for a bosonic mode.
Parameters
==========
alpha : Number, Symbol
The complex amplitude of the coherent state.
"""
def __new__(cls, alpha):
return Bra.__new__(cls, alpha)
@property
def alpha(self):
return self.label[0]
@classmethod
def dual_class(self):
return BosonCoherentKet
def _apply_operator_BosonOp(self, op, **options):
if not op.is_annihilation:
return self.alpha * self
else:
return None
PK ]ZZZ�\}��# �# " sympy/physics/quantum/cartesian.py"""Operators and states for 1D cartesian position and momentum.
TODO:
* Add 3D classes to mappings in operatorset.py
"""
from sympy.core.numbers import (I, pi)
from sympy.core.singleton import S
from sympy.functions.elementary.exponential import exp
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.special.delta_functions import DiracDelta
from sympy.sets.sets import Interval
from sympy.physics.quantum.constants import hbar
from sympy.physics.quantum.hilbert import L2
from sympy.physics.quantum.operator import DifferentialOperator, HermitianOperator
from sympy.physics.quantum.state import Ket, Bra, State
__all__ = [
'XOp',
'YOp',
'ZOp',
'PxOp',
'X',
'Y',
'Z',
'Px',
'XKet',
'XBra',
'PxKet',
'PxBra',
'PositionState3D',
'PositionKet3D',
'PositionBra3D'
]
#-------------------------------------------------------------------------
# Position operators
#-------------------------------------------------------------------------
class XOp(HermitianOperator):
"""1D cartesian position operator."""
@classmethod
def default_args(self):
return ("X",)
@classmethod
def _eval_hilbert_space(self, args):
return L2(Interval(S.NegativeInfinity, S.Infinity))
def _eval_commutator_PxOp(self, other):
return I*hbar
def _apply_operator_XKet(self, ket, **options):
return ket.position*ket
def _apply_operator_PositionKet3D(self, ket, **options):
return ket.position_x*ket
def _represent_PxKet(self, basis, *, index=1, **options):
states = basis._enumerate_state(2, start_index=index)
coord1 = states[0].momentum
coord2 = states[1].momentum
d = DifferentialOperator(coord1)
delta = DiracDelta(coord1 - coord2)
return I*hbar*(d*delta)
class YOp(HermitianOperator):
""" Y cartesian coordinate operator (for 2D or 3D systems) """
@classmethod
def default_args(self):
return ("Y",)
@classmethod
def _eval_hilbert_space(self, args):
return L2(Interval(S.NegativeInfinity, S.Infinity))
def _apply_operator_PositionKet3D(self, ket, **options):
return ket.position_y*ket
class ZOp(HermitianOperator):
""" Z cartesian coordinate operator (for 3D systems) """
@classmethod
def default_args(self):
return ("Z",)
@classmethod
def _eval_hilbert_space(self, args):
return L2(Interval(S.NegativeInfinity, S.Infinity))
def _apply_operator_PositionKet3D(self, ket, **options):
return ket.position_z*ket
#-------------------------------------------------------------------------
# Momentum operators
#-------------------------------------------------------------------------
class PxOp(HermitianOperator):
"""1D cartesian momentum operator."""
@classmethod
def default_args(self):
return ("Px",)
@classmethod
def _eval_hilbert_space(self, args):
return L2(Interval(S.NegativeInfinity, S.Infinity))
def _apply_operator_PxKet(self, ket, **options):
return ket.momentum*ket
def _represent_XKet(self, basis, *, index=1, **options):
states = basis._enumerate_state(2, start_index=index)
coord1 = states[0].position
coord2 = states[1].position
d = DifferentialOperator(coord1)
delta = DiracDelta(coord1 - coord2)
return -I*hbar*(d*delta)
X = XOp('X')
Y = YOp('Y')
Z = ZOp('Z')
Px = PxOp('Px')
#-------------------------------------------------------------------------
# Position eigenstates
#-------------------------------------------------------------------------
class XKet(Ket):
"""1D cartesian position eigenket."""
@classmethod
def _operators_to_state(self, op, **options):
return self.__new__(self, *_lowercase_labels(op), **options)
def _state_to_operators(self, op_class, **options):
return op_class.__new__(op_class,
*_uppercase_labels(self), **options)
@classmethod
def default_args(self):
return ("x",)
@classmethod
def dual_class(self):
return XBra
@property
def position(self):
"""The position of the state."""
return self.label[0]
def _enumerate_state(self, num_states, **options):
return _enumerate_continuous_1D(self, num_states, **options)
def _eval_innerproduct_XBra(self, bra, **hints):
return DiracDelta(self.position - bra.position)
def _eval_innerproduct_PxBra(self, bra, **hints):
return exp(-I*self.position*bra.momentum/hbar)/sqrt(2*pi*hbar)
class XBra(Bra):
"""1D cartesian position eigenbra."""
@classmethod
def default_args(self):
return ("x",)
@classmethod
def dual_class(self):
return XKet
@property
def position(self):
"""The position of the state."""
return self.label[0]
class PositionState3D(State):
""" Base class for 3D cartesian position eigenstates """
@classmethod
def _operators_to_state(self, op, **options):
return self.__new__(self, *_lowercase_labels(op), **options)
def _state_to_operators(self, op_class, **options):
return op_class.__new__(op_class,
*_uppercase_labels(self), **options)
@classmethod
def default_args(self):
return ("x", "y", "z")
@property
def position_x(self):
""" The x coordinate of the state """
return self.label[0]
@property
def position_y(self):
""" The y coordinate of the state """
return self.label[1]
@property
def position_z(self):
""" The z coordinate of the state """
return self.label[2]
class PositionKet3D(Ket, PositionState3D):
""" 3D cartesian position eigenket """
def _eval_innerproduct_PositionBra3D(self, bra, **options):
x_diff = self.position_x - bra.position_x
y_diff = self.position_y - bra.position_y
z_diff = self.position_z - bra.position_z
return DiracDelta(x_diff)*DiracDelta(y_diff)*DiracDelta(z_diff)
@classmethod
def dual_class(self):
return PositionBra3D
# XXX: The type:ignore here is because mypy gives Definition of
# "_state_to_operators" in base class "PositionState3D" is incompatible with
# definition in base class "BraBase"
class PositionBra3D(Bra, PositionState3D): # type: ignore
""" 3D cartesian position eigenbra """
@classmethod
def dual_class(self):
return PositionKet3D
#-------------------------------------------------------------------------
# Momentum eigenstates
#-------------------------------------------------------------------------
class PxKet(Ket):
"""1D cartesian momentum eigenket."""
@classmethod
def _operators_to_state(self, op, **options):
return self.__new__(self, *_lowercase_labels(op), **options)
def _state_to_operators(self, op_class, **options):
return op_class.__new__(op_class,
*_uppercase_labels(self), **options)
@classmethod
def default_args(self):
return ("px",)
@classmethod
def dual_class(self):
return PxBra
@property
def momentum(self):
"""The momentum of the state."""
return self.label[0]
def _enumerate_state(self, *args, **options):
return _enumerate_continuous_1D(self, *args, **options)
def _eval_innerproduct_XBra(self, bra, **hints):
return exp(I*self.momentum*bra.position/hbar)/sqrt(2*pi*hbar)
def _eval_innerproduct_PxBra(self, bra, **hints):
return DiracDelta(self.momentum - bra.momentum)
class PxBra(Bra):
"""1D cartesian momentum eigenbra."""
@classmethod
def default_args(self):
return ("px",)
@classmethod
def dual_class(self):
return PxKet
@property
def momentum(self):
"""The momentum of the state."""
return self.label[0]
#-------------------------------------------------------------------------
# Global helper functions
#-------------------------------------------------------------------------
def _enumerate_continuous_1D(*args, **options):
state = args[0]
num_states = args[1]
state_class = state.__class__
index_list = options.pop('index_list', [])
if len(index_list) == 0:
start_index = options.pop('start_index', 1)
index_list = list(range(start_index, start_index + num_states))
enum_states = [0 for i in range(len(index_list))]
for i, ind in enumerate(index_list):
label = state.args[0]
enum_states[i] = state_class(str(label) + "_" + str(ind), **options)
return enum_states
def _lowercase_labels(ops):
if not isinstance(ops, set):
ops = [ops]
return [str(arg.label[0]).lower() for arg in ops]
def _uppercase_labels(ops):
if not isinstance(ops, set):
ops = [ops]
new_args = [str(arg.label[0])[0].upper() +
str(arg.label[0])[1:] for arg in ops]
return new_args
PK ]ZZZ� Q<[ [ sympy/physics/quantum/cg.py#TODO:
# -Implement Clebsch-Gordan symmetries
# -Improve simplification method
# -Implement new simplifications
"""Clebsch-Gordon Coefficients."""
from sympy.concrete.summations import Sum
from sympy.core.add import Add
from sympy.core.expr import Expr
from sympy.core.function import expand
from sympy.core.mul import Mul
from sympy.core.power import Pow
from sympy.core.relational import Eq
from sympy.core.singleton import S
from sympy.core.symbol import (Wild, symbols)
from sympy.core.sympify import sympify
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.elementary.piecewise import Piecewise
from sympy.printing.pretty.stringpict import prettyForm, stringPict
from sympy.functions.special.tensor_functions import KroneckerDelta
from sympy.physics.wigner import clebsch_gordan, wigner_3j, wigner_6j, wigner_9j
from sympy.printing.precedence import PRECEDENCE
__all__ = [
'CG',
'Wigner3j',
'Wigner6j',
'Wigner9j',
'cg_simp'
]
#-----------------------------------------------------------------------------
# CG Coefficients
#-----------------------------------------------------------------------------
class Wigner3j(Expr):
"""Class for the Wigner-3j symbols.
Explanation
===========
Wigner 3j-symbols are coefficients determined by the coupling of
two angular momenta. When created, they are expressed as symbolic
quantities that, for numerical parameters, can be evaluated using the
``.doit()`` method [1]_.
Parameters
==========
j1, m1, j2, m2, j3, m3 : Number, Symbol
Terms determining the angular momentum of coupled angular momentum
systems.
Examples
========
Declare a Wigner-3j coefficient and calculate its value
>>> from sympy.physics.quantum.cg import Wigner3j
>>> w3j = Wigner3j(6,0,4,0,2,0)
>>> w3j
Wigner3j(6, 0, 4, 0, 2, 0)
>>> w3j.doit()
sqrt(715)/143
See Also
========
CG: Clebsch-Gordan coefficients
References
==========
.. [1] Varshalovich, D A, Quantum Theory of Angular Momentum. 1988.
"""
is_commutative = True
def __new__(cls, j1, m1, j2, m2, j3, m3):
args = map(sympify, (j1, m1, j2, m2, j3, m3))
return Expr.__new__(cls, *args)
@property
def j1(self):
return self.args[0]
@property
def m1(self):
return self.args[1]
@property
def j2(self):
return self.args[2]
@property
def m2(self):
return self.args[3]
@property
def j3(self):
return self.args[4]
@property
def m3(self):
return self.args[5]
@property
def is_symbolic(self):
return not all(arg.is_number for arg in self.args)
# This is modified from the _print_Matrix method
def _pretty(self, printer, *args):
m = ((printer._print(self.j1), printer._print(self.m1)),
(printer._print(self.j2), printer._print(self.m2)),
(printer._print(self.j3), printer._print(self.m3)))
hsep = 2
vsep = 1
maxw = [-1]*3
for j in range(3):
maxw[j] = max(m[j][i].width() for i in range(2))
D = None
for i in range(2):
D_row = None
for j in range(3):
s = m[j][i]
wdelta = maxw[j] - s.width()
wleft = wdelta //2
wright = wdelta - wleft
s = prettyForm(*s.right(' '*wright))
s = prettyForm(*s.left(' '*wleft))
if D_row is None:
D_row = s
continue
D_row = prettyForm(*D_row.right(' '*hsep))
D_row = prettyForm(*D_row.right(s))
if D is None:
D = D_row
continue
for _ in range(vsep):
D = prettyForm(*D.below(' '))
D = prettyForm(*D.below(D_row))
D = prettyForm(*D.parens())
return D
def _latex(self, printer, *args):
label = map(printer._print, (self.j1, self.j2, self.j3,
self.m1, self.m2, self.m3))
return r'\left(\begin{array}{ccc} %s & %s & %s \\ %s & %s & %s \end{array}\right)' % \
tuple(label)
def doit(self, **hints):
if self.is_symbolic:
raise ValueError("Coefficients must be numerical")
return wigner_3j(self.j1, self.j2, self.j3, self.m1, self.m2, self.m3)
class CG(Wigner3j):
r"""Class for Clebsch-Gordan coefficient.
Explanation
===========
Clebsch-Gordan coefficients describe the angular momentum coupling between
two systems. The coefficients give the expansion of a coupled total angular
momentum state and an uncoupled tensor product state. The Clebsch-Gordan
coefficients are defined as [1]_:
.. math ::
C^{j_3,m_3}_{j_1,m_1,j_2,m_2} = \left\langle j_1,m_1;j_2,m_2 | j_3,m_3\right\rangle
Parameters
==========
j1, m1, j2, m2 : Number, Symbol
Angular momenta of states 1 and 2.
j3, m3: Number, Symbol
Total angular momentum of the coupled system.
Examples
========
Define a Clebsch-Gordan coefficient and evaluate its value
>>> from sympy.physics.quantum.cg import CG
>>> from sympy import S
>>> cg = CG(S(3)/2, S(3)/2, S(1)/2, -S(1)/2, 1, 1)
>>> cg
CG(3/2, 3/2, 1/2, -1/2, 1, 1)
>>> cg.doit()
sqrt(3)/2
>>> CG(j1=S(1)/2, m1=-S(1)/2, j2=S(1)/2, m2=+S(1)/2, j3=1, m3=0).doit()
sqrt(2)/2
Compare [2]_.
See Also
========
Wigner3j: Wigner-3j symbols
References
==========
.. [1] Varshalovich, D A, Quantum Theory of Angular Momentum. 1988.
.. [2] `Clebsch-Gordan Coefficients, Spherical Harmonics, and d Functions
<https://pdg.lbl.gov/2020/reviews/rpp2020-rev-clebsch-gordan-coefs.pdf>`_
in P.A. Zyla *et al.* (Particle Data Group), Prog. Theor. Exp. Phys.
2020, 083C01 (2020).
"""
precedence = PRECEDENCE["Pow"] - 1
def doit(self, **hints):
if self.is_symbolic:
raise ValueError("Coefficients must be numerical")
return clebsch_gordan(self.j1, self.j2, self.j3, self.m1, self.m2, self.m3)
def _pretty(self, printer, *args):
bot = printer._print_seq(
(self.j1, self.m1, self.j2, self.m2), delimiter=',')
top = printer._print_seq((self.j3, self.m3), delimiter=',')
pad = max(top.width(), bot.width())
bot = prettyForm(*bot.left(' '))
top = prettyForm(*top.left(' '))
if not pad == bot.width():
bot = prettyForm(*bot.right(' '*(pad - bot.width())))
if not pad == top.width():
top = prettyForm(*top.right(' '*(pad - top.width())))
s = stringPict('C' + ' '*pad)
s = prettyForm(*s.below(bot))
s = prettyForm(*s.above(top))
return s
def _latex(self, printer, *args):
label = map(printer._print, (self.j3, self.m3, self.j1,
self.m1, self.j2, self.m2))
return r'C^{%s,%s}_{%s,%s,%s,%s}' % tuple(label)
class Wigner6j(Expr):
"""Class for the Wigner-6j symbols
See Also
========
Wigner3j: Wigner-3j symbols
"""
def __new__(cls, j1, j2, j12, j3, j, j23):
args = map(sympify, (j1, j2, j12, j3, j, j23))
return Expr.__new__(cls, *args)
@property
def j1(self):
return self.args[0]
@property
def j2(self):
return self.args[1]
@property
def j12(self):
return self.args[2]
@property
def j3(self):
return self.args[3]
@property
def j(self):
return self.args[4]
@property
def j23(self):
return self.args[5]
@property
def is_symbolic(self):
return not all(arg.is_number for arg in self.args)
# This is modified from the _print_Matrix method
def _pretty(self, printer, *args):
m = ((printer._print(self.j1), printer._print(self.j3)),
(printer._print(self.j2), printer._print(self.j)),
(printer._print(self.j12), printer._print(self.j23)))
hsep = 2
vsep = 1
maxw = [-1]*3
for j in range(3):
maxw[j] = max(m[j][i].width() for i in range(2))
D = None
for i in range(2):
D_row = None
for j in range(3):
s = m[j][i]
wdelta = maxw[j] - s.width()
wleft = wdelta //2
wright = wdelta - wleft
s = prettyForm(*s.right(' '*wright))
s = prettyForm(*s.left(' '*wleft))
if D_row is None:
D_row = s
continue
D_row = prettyForm(*D_row.right(' '*hsep))
D_row = prettyForm(*D_row.right(s))
if D is None:
D = D_row
continue
for _ in range(vsep):
D = prettyForm(*D.below(' '))
D = prettyForm(*D.below(D_row))
D = prettyForm(*D.parens(left='{', right='}'))
return D
def _latex(self, printer, *args):
label = map(printer._print, (self.j1, self.j2, self.j12,
self.j3, self.j, self.j23))
return r'\left\{\begin{array}{ccc} %s & %s & %s \\ %s & %s & %s \end{array}\right\}' % \
tuple(label)
def doit(self, **hints):
if self.is_symbolic:
raise ValueError("Coefficients must be numerical")
return wigner_6j(self.j1, self.j2, self.j12, self.j3, self.j, self.j23)
class Wigner9j(Expr):
"""Class for the Wigner-9j symbols
See Also
========
Wigner3j: Wigner-3j symbols
"""
def __new__(cls, j1, j2, j12, j3, j4, j34, j13, j24, j):
args = map(sympify, (j1, j2, j12, j3, j4, j34, j13, j24, j))
return Expr.__new__(cls, *args)
@property
def j1(self):
return self.args[0]
@property
def j2(self):
return self.args[1]
@property
def j12(self):
return self.args[2]
@property
def j3(self):
return self.args[3]
@property
def j4(self):
return self.args[4]
@property
def j34(self):
return self.args[5]
@property
def j13(self):
return self.args[6]
@property
def j24(self):
return self.args[7]
@property
def j(self):
return self.args[8]
@property
def is_symbolic(self):
return not all(arg.is_number for arg in self.args)
# This is modified from the _print_Matrix method
def _pretty(self, printer, *args):
m = (
(printer._print(
self.j1), printer._print(self.j3), printer._print(self.j13)),
(printer._print(
self.j2), printer._print(self.j4), printer._print(self.j24)),
(printer._print(self.j12), printer._print(self.j34), printer._print(self.j)))
hsep = 2
vsep = 1
maxw = [-1]*3
for j in range(3):
maxw[j] = max(m[j][i].width() for i in range(3))
D = None
for i in range(3):
D_row = None
for j in range(3):
s = m[j][i]
wdelta = maxw[j] - s.width()
wleft = wdelta //2
wright = wdelta - wleft
s = prettyForm(*s.right(' '*wright))
s = prettyForm(*s.left(' '*wleft))
if D_row is None:
D_row = s
continue
D_row = prettyForm(*D_row.right(' '*hsep))
D_row = prettyForm(*D_row.right(s))
if D is None:
D = D_row
continue
for _ in range(vsep):
D = prettyForm(*D.below(' '))
D = prettyForm(*D.below(D_row))
D = prettyForm(*D.parens(left='{', right='}'))
return D
def _latex(self, printer, *args):
label = map(printer._print, (self.j1, self.j2, self.j12, self.j3,
self.j4, self.j34, self.j13, self.j24, self.j))
return r'\left\{\begin{array}{ccc} %s & %s & %s \\ %s & %s & %s \\ %s & %s & %s \end{array}\right\}' % \
tuple(label)
def doit(self, **hints):
if self.is_symbolic:
raise ValueError("Coefficients must be numerical")
return wigner_9j(self.j1, self.j2, self.j12, self.j3, self.j4, self.j34, self.j13, self.j24, self.j)
def cg_simp(e):
"""Simplify and combine CG coefficients.
Explanation
===========
This function uses various symmetry and properties of sums and
products of Clebsch-Gordan coefficients to simplify statements
involving these terms [1]_.
Examples
========
Simplify the sum over CG(a,alpha,0,0,a,alpha) for all alpha to
2*a+1
>>> from sympy.physics.quantum.cg import CG, cg_simp
>>> a = CG(1,1,0,0,1,1)
>>> b = CG(1,0,0,0,1,0)
>>> c = CG(1,-1,0,0,1,-1)
>>> cg_simp(a+b+c)
3
See Also
========
CG: Clebsh-Gordan coefficients
References
==========
.. [1] Varshalovich, D A, Quantum Theory of Angular Momentum. 1988.
"""
if isinstance(e, Add):
return _cg_simp_add(e)
elif isinstance(e, Sum):
return _cg_simp_sum(e)
elif isinstance(e, Mul):
return Mul(*[cg_simp(arg) for arg in e.args])
elif isinstance(e, Pow):
return Pow(cg_simp(e.base), e.exp)
else:
return e
def _cg_simp_add(e):
#TODO: Improve simplification method
"""Takes a sum of terms involving Clebsch-Gordan coefficients and
simplifies the terms.
Explanation
===========
First, we create two lists, cg_part, which is all the terms involving CG
coefficients, and other_part, which is all other terms. The cg_part list
is then passed to the simplification methods, which return the new cg_part
and any additional terms that are added to other_part
"""
cg_part = []
other_part = []
e = expand(e)
for arg in e.args:
if arg.has(CG):
if isinstance(arg, Sum):
other_part.append(_cg_simp_sum(arg))
elif isinstance(arg, Mul):
terms = 1
for term in arg.args:
if isinstance(term, Sum):
terms *= _cg_simp_sum(term)
else:
terms *= term
if terms.has(CG):
cg_part.append(terms)
else:
other_part.append(terms)
else:
cg_part.append(arg)
else:
other_part.append(arg)
cg_part, other = _check_varsh_871_1(cg_part)
other_part.append(other)
cg_part, other = _check_varsh_871_2(cg_part)
other_part.append(other)
cg_part, other = _check_varsh_872_9(cg_part)
other_part.append(other)
return Add(*cg_part) + Add(*other_part)
def _check_varsh_871_1(term_list):
# Sum( CG(a,alpha,b,0,a,alpha), (alpha, -a, a)) == KroneckerDelta(b,0)
a, alpha, b, lt = map(Wild, ('a', 'alpha', 'b', 'lt'))
expr = lt*CG(a, alpha, b, 0, a, alpha)
simp = (2*a + 1)*KroneckerDelta(b, 0)
sign = lt/abs(lt)
build_expr = 2*a + 1
index_expr = a + alpha
return _check_cg_simp(expr, simp, sign, lt, term_list, (a, alpha, b, lt), (a, b), build_expr, index_expr)
def _check_varsh_871_2(term_list):
# Sum((-1)**(a-alpha)*CG(a,alpha,a,-alpha,c,0),(alpha,-a,a))
a, alpha, c, lt = map(Wild, ('a', 'alpha', 'c', 'lt'))
expr = lt*CG(a, alpha, a, -alpha, c, 0)
simp = sqrt(2*a + 1)*KroneckerDelta(c, 0)
sign = (-1)**(a - alpha)*lt/abs(lt)
build_expr = 2*a + 1
index_expr = a + alpha
return _check_cg_simp(expr, simp, sign, lt, term_list, (a, alpha, c, lt), (a, c), build_expr, index_expr)
def _check_varsh_872_9(term_list):
# Sum( CG(a,alpha,b,beta,c,gamma)*CG(a,alpha',b,beta',c,gamma), (gamma, -c, c), (c, abs(a-b), a+b))
a, alpha, alphap, b, beta, betap, c, gamma, lt = map(Wild, (
'a', 'alpha', 'alphap', 'b', 'beta', 'betap', 'c', 'gamma', 'lt'))
# Case alpha==alphap, beta==betap
# For numerical alpha,beta
expr = lt*CG(a, alpha, b, beta, c, gamma)**2
simp = S.One
sign = lt/abs(lt)
x = abs(a - b)
y = abs(alpha + beta)
build_expr = a + b + 1 - Piecewise((x, x > y), (0, Eq(x, y)), (y, y > x))
index_expr = a + b - c
term_list, other1 = _check_cg_simp(expr, simp, sign, lt, term_list, (a, alpha, b, beta, c, gamma, lt), (a, alpha, b, beta), build_expr, index_expr)
# For symbolic alpha,beta
x = abs(a - b)
y = a + b
build_expr = (y + 1 - x)*(x + y + 1)
index_expr = (c - x)*(x + c) + c + gamma
term_list, other2 = _check_cg_simp(expr, simp, sign, lt, term_list, (a, alpha, b, beta, c, gamma, lt), (a, alpha, b, beta), build_expr, index_expr)
# Case alpha!=alphap or beta!=betap
# Note: this only works with leading term of 1, pattern matching is unable to match when there is a Wild leading term
# For numerical alpha,alphap,beta,betap
expr = CG(a, alpha, b, beta, c, gamma)*CG(a, alphap, b, betap, c, gamma)
simp = KroneckerDelta(alpha, alphap)*KroneckerDelta(beta, betap)
sign = S.One
x = abs(a - b)
y = abs(alpha + beta)
build_expr = a + b + 1 - Piecewise((x, x > y), (0, Eq(x, y)), (y, y > x))
index_expr = a + b - c
term_list, other3 = _check_cg_simp(expr, simp, sign, S.One, term_list, (a, alpha, alphap, b, beta, betap, c, gamma), (a, alpha, alphap, b, beta, betap), build_expr, index_expr)
# For symbolic alpha,alphap,beta,betap
x = abs(a - b)
y = a + b
build_expr = (y + 1 - x)*(x + y + 1)
index_expr = (c - x)*(x + c) + c + gamma
term_list, other4 = _check_cg_simp(expr, simp, sign, S.One, term_list, (a, alpha, alphap, b, beta, betap, c, gamma), (a, alpha, alphap, b, beta, betap), build_expr, index_expr)
return term_list, other1 + other2 + other4
def _check_cg_simp(expr, simp, sign, lt, term_list, variables, dep_variables, build_index_expr, index_expr):
""" Checks for simplifications that can be made, returning a tuple of the
simplified list of terms and any terms generated by simplification.
Parameters
==========
expr: expression
The expression with Wild terms that will be matched to the terms in
the sum
simp: expression
The expression with Wild terms that is substituted in place of the CG
terms in the case of simplification
sign: expression
The expression with Wild terms denoting the sign that is on expr that
must match
lt: expression
The expression with Wild terms that gives the leading term of the
matched expr
term_list: list
A list of all of the terms is the sum to be simplified
variables: list
A list of all the variables that appears in expr
dep_variables: list
A list of the variables that must match for all the terms in the sum,
i.e. the dependent variables
build_index_expr: expression
Expression with Wild terms giving the number of elements in cg_index
index_expr: expression
Expression with Wild terms giving the index terms have when storing
them to cg_index
"""
other_part = 0
i = 0
while i < len(term_list):
sub_1 = _check_cg(term_list[i], expr, len(variables))
if sub_1 is None:
i += 1
continue
if not build_index_expr.subs(sub_1).is_number:
i += 1
continue
sub_dep = [(x, sub_1[x]) for x in dep_variables]
cg_index = [None]*build_index_expr.subs(sub_1)
for j in range(i, len(term_list)):
sub_2 = _check_cg(term_list[j], expr.subs(sub_dep), len(variables) - len(dep_variables), sign=(sign.subs(sub_1), sign.subs(sub_dep)))
if sub_2 is None:
continue
if not index_expr.subs(sub_dep).subs(sub_2).is_number:
continue
cg_index[index_expr.subs(sub_dep).subs(sub_2)] = j, expr.subs(lt, 1).subs(sub_dep).subs(sub_2), lt.subs(sub_2), sign.subs(sub_dep).subs(sub_2)
if not any(i is None for i in cg_index):
min_lt = min(*[ abs(term[2]) for term in cg_index ])
indices = [ term[0] for term in cg_index]
indices.sort()
indices.reverse()
[ term_list.pop(j) for j in indices ]
for term in cg_index:
if abs(term[2]) > min_lt:
term_list.append( (term[2] - min_lt*term[3])*term[1] )
other_part += min_lt*(sign*simp).subs(sub_1)
else:
i += 1
return term_list, other_part
def _check_cg(cg_term, expr, length, sign=None):
"""Checks whether a term matches the given expression"""
# TODO: Check for symmetries
matches = cg_term.match(expr)
if matches is None:
return
if sign is not None:
if not isinstance(sign, tuple):
raise TypeError('sign must be a tuple')
if not sign[0] == (sign[1]).subs(matches):
return
if len(matches) == length:
return matches
def _cg_simp_sum(e):
e = _check_varsh_sum_871_1(e)
e = _check_varsh_sum_871_2(e)
e = _check_varsh_sum_872_4(e)
return e
def _check_varsh_sum_871_1(e):
a = Wild('a')
alpha = symbols('alpha')
b = Wild('b')
match = e.match(Sum(CG(a, alpha, b, 0, a, alpha), (alpha, -a, a)))
if match is not None and len(match) == 2:
return ((2*a + 1)*KroneckerDelta(b, 0)).subs(match)
return e
def _check_varsh_sum_871_2(e):
a = Wild('a')
alpha = symbols('alpha')
c = Wild('c')
match = e.match(
Sum((-1)**(a - alpha)*CG(a, alpha, a, -alpha, c, 0), (alpha, -a, a)))
if match is not None and len(match) == 2:
return (sqrt(2*a + 1)*KroneckerDelta(c, 0)).subs(match)
return e
def _check_varsh_sum_872_4(e):
alpha = symbols('alpha')
beta = symbols('beta')
a = Wild('a')
b = Wild('b')
c = Wild('c')
cp = Wild('cp')
gamma = Wild('gamma')
gammap = Wild('gammap')
cg1 = CG(a, alpha, b, beta, c, gamma)
cg2 = CG(a, alpha, b, beta, cp, gammap)
match1 = e.match(Sum(cg1*cg2, (alpha, -a, a), (beta, -b, b)))
if match1 is not None and len(match1) == 6:
return (KroneckerDelta(c, cp)*KroneckerDelta(gamma, gammap)).subs(match1)
match2 = e.match(Sum(cg1**2, (alpha, -a, a), (beta, -b, b)))
if match2 is not None and len(match2) == 4:
return S.One
return e
def _cg_list(term):
if isinstance(term, CG):
return (term,), 1, 1
cg = []
coeff = 1
if not isinstance(term, (Mul, Pow)):
raise NotImplementedError('term must be CG, Add, Mul or Pow')
if isinstance(term, Pow) and term.exp.is_number:
if term.exp.is_number:
[ cg.append(term.base) for _ in range(term.exp) ]
else:
return (term,), 1, 1
if isinstance(term, Mul):
for arg in term.args:
if isinstance(arg, CG):
cg.append(arg)
else:
coeff *= arg
return cg, coeff, coeff/abs(coeff)
PK ]ZZZ��� . . $ sympy/physics/quantum/circuitplot.py"""Matplotlib based plotting of quantum circuits.
Todo:
* Optimize printing of large circuits.
* Get this to work with single gates.
* Do a better job checking the form of circuits to make sure it is a Mul of
Gates.
* Get multi-target gates plotting.
* Get initial and final states to plot.
* Get measurements to plot. Might need to rethink measurement as a gate
issue.
* Get scale and figsize to be handled in a better way.
* Write some tests/examples!
"""
from __future__ import annotations
from sympy.core.mul import Mul
from sympy.external import import_module
from sympy.physics.quantum.gate import Gate, OneQubitGate, CGate, CGateS
__all__ = [
'CircuitPlot',
'circuit_plot',
'labeller',
'Mz',
'Mx',
'CreateOneQubitGate',
'CreateCGate',
]
np = import_module('numpy')
matplotlib = import_module(
'matplotlib', import_kwargs={'fromlist': ['pyplot']},
catch=(RuntimeError,)) # This is raised in environments that have no display.
if np and matplotlib:
pyplot = matplotlib.pyplot
Line2D = matplotlib.lines.Line2D
Circle = matplotlib.patches.Circle
#from matplotlib import rc
#rc('text',usetex=True)
class CircuitPlot:
"""A class for managing a circuit plot."""
scale = 1.0
fontsize = 20.0
linewidth = 1.0
control_radius = 0.05
not_radius = 0.15
swap_delta = 0.05
labels: list[str] = []
inits: dict[str, str] = {}
label_buffer = 0.5
def __init__(self, c, nqubits, **kwargs):
if not np or not matplotlib:
raise ImportError('numpy or matplotlib not available.')
self.circuit = c
self.ngates = len(self.circuit.args)
self.nqubits = nqubits
self.update(kwargs)
self._create_grid()
self._create_figure()
self._plot_wires()
self._plot_gates()
self._finish()
def update(self, kwargs):
"""Load the kwargs into the instance dict."""
self.__dict__.update(kwargs)
def _create_grid(self):
"""Create the grid of wires."""
scale = self.scale
wire_grid = np.arange(0.0, self.nqubits*scale, scale, dtype=float)
gate_grid = np.arange(0.0, self.ngates*scale, scale, dtype=float)
self._wire_grid = wire_grid
self._gate_grid = gate_grid
def _create_figure(self):
"""Create the main matplotlib figure."""
self._figure = pyplot.figure(
figsize=(self.ngates*self.scale, self.nqubits*self.scale),
facecolor='w',
edgecolor='w'
)
ax = self._figure.add_subplot(
1, 1, 1,
frameon=True
)
ax.set_axis_off()
offset = 0.5*self.scale
ax.set_xlim(self._gate_grid[0] - offset, self._gate_grid[-1] + offset)
ax.set_ylim(self._wire_grid[0] - offset, self._wire_grid[-1] + offset)
ax.set_aspect('equal')
self._axes = ax
def _plot_wires(self):
"""Plot the wires of the circuit diagram."""
xstart = self._gate_grid[0]
xstop = self._gate_grid[-1]
xdata = (xstart - self.scale, xstop + self.scale)
for i in range(self.nqubits):
ydata = (self._wire_grid[i], self._wire_grid[i])
line = Line2D(
xdata, ydata,
color='k',
lw=self.linewidth
)
self._axes.add_line(line)
if self.labels:
init_label_buffer = 0
if self.inits.get(self.labels[i]): init_label_buffer = 0.25
self._axes.text(
xdata[0]-self.label_buffer-init_label_buffer,ydata[0],
render_label(self.labels[i],self.inits),
size=self.fontsize,
color='k',ha='center',va='center')
self._plot_measured_wires()
def _plot_measured_wires(self):
ismeasured = self._measurements()
xstop = self._gate_grid[-1]
dy = 0.04 # amount to shift wires when doubled
# Plot doubled wires after they are measured
for im in ismeasured:
xdata = (self._gate_grid[ismeasured[im]],xstop+self.scale)
ydata = (self._wire_grid[im]+dy,self._wire_grid[im]+dy)
line = Line2D(
xdata, ydata,
color='k',
lw=self.linewidth
)
self._axes.add_line(line)
# Also double any controlled lines off these wires
for i,g in enumerate(self._gates()):
if isinstance(g, (CGate, CGateS)):
wires = g.controls + g.targets
for wire in wires:
if wire in ismeasured and \
self._gate_grid[i] > self._gate_grid[ismeasured[wire]]:
ydata = min(wires), max(wires)
xdata = self._gate_grid[i]-dy, self._gate_grid[i]-dy
line = Line2D(
xdata, ydata,
color='k',
lw=self.linewidth
)
self._axes.add_line(line)
def _gates(self):
"""Create a list of all gates in the circuit plot."""
gates = []
if isinstance(self.circuit, Mul):
for g in reversed(self.circuit.args):
if isinstance(g, Gate):
gates.append(g)
elif isinstance(self.circuit, Gate):
gates.append(self.circuit)
return gates
def _plot_gates(self):
"""Iterate through the gates and plot each of them."""
for i, gate in enumerate(self._gates()):
gate.plot_gate(self, i)
def _measurements(self):
"""Return a dict ``{i:j}`` where i is the index of the wire that has
been measured, and j is the gate where the wire is measured.
"""
ismeasured = {}
for i,g in enumerate(self._gates()):
if getattr(g,'measurement',False):
for target in g.targets:
if target in ismeasured:
if ismeasured[target] > i:
ismeasured[target] = i
else:
ismeasured[target] = i
return ismeasured
def _finish(self):
# Disable clipping to make panning work well for large circuits.
for o in self._figure.findobj():
o.set_clip_on(False)
def one_qubit_box(self, t, gate_idx, wire_idx):
"""Draw a box for a single qubit gate."""
x = self._gate_grid[gate_idx]
y = self._wire_grid[wire_idx]
self._axes.text(
x, y, t,
color='k',
ha='center',
va='center',
bbox={"ec": 'k', "fc": 'w', "fill": True, "lw": self.linewidth},
size=self.fontsize
)
def two_qubit_box(self, t, gate_idx, wire_idx):
"""Draw a box for a two qubit gate. Does not work yet.
"""
# x = self._gate_grid[gate_idx]
# y = self._wire_grid[wire_idx]+0.5
print(self._gate_grid)
print(self._wire_grid)
# unused:
# obj = self._axes.text(
# x, y, t,
# color='k',
# ha='center',
# va='center',
# bbox=dict(ec='k', fc='w', fill=True, lw=self.linewidth),
# size=self.fontsize
# )
def control_line(self, gate_idx, min_wire, max_wire):
"""Draw a vertical control line."""
xdata = (self._gate_grid[gate_idx], self._gate_grid[gate_idx])
ydata = (self._wire_grid[min_wire], self._wire_grid[max_wire])
line = Line2D(
xdata, ydata,
color='k',
lw=self.linewidth
)
self._axes.add_line(line)
def control_point(self, gate_idx, wire_idx):
"""Draw a control point."""
x = self._gate_grid[gate_idx]
y = self._wire_grid[wire_idx]
radius = self.control_radius
c = Circle(
(x, y),
radius*self.scale,
ec='k',
fc='k',
fill=True,
lw=self.linewidth
)
self._axes.add_patch(c)
def not_point(self, gate_idx, wire_idx):
"""Draw a NOT gates as the circle with plus in the middle."""
x = self._gate_grid[gate_idx]
y = self._wire_grid[wire_idx]
radius = self.not_radius
c = Circle(
(x, y),
radius,
ec='k',
fc='w',
fill=False,
lw=self.linewidth
)
self._axes.add_patch(c)
l = Line2D(
(x, x), (y - radius, y + radius),
color='k',
lw=self.linewidth
)
self._axes.add_line(l)
def swap_point(self, gate_idx, wire_idx):
"""Draw a swap point as a cross."""
x = self._gate_grid[gate_idx]
y = self._wire_grid[wire_idx]
d = self.swap_delta
l1 = Line2D(
(x - d, x + d),
(y - d, y + d),
color='k',
lw=self.linewidth
)
l2 = Line2D(
(x - d, x + d),
(y + d, y - d),
color='k',
lw=self.linewidth
)
self._axes.add_line(l1)
self._axes.add_line(l2)
def circuit_plot(c, nqubits, **kwargs):
"""Draw the circuit diagram for the circuit with nqubits.
Parameters
==========
c : circuit
The circuit to plot. Should be a product of Gate instances.
nqubits : int
The number of qubits to include in the circuit. Must be at least
as big as the largest ``min_qubits`` of the gates.
"""
return CircuitPlot(c, nqubits, **kwargs)
def render_label(label, inits={}):
"""Slightly more flexible way to render labels.
>>> from sympy.physics.quantum.circuitplot import render_label
>>> render_label('q0')
'$\\\\left|q0\\\\right\\\\rangle$'
>>> render_label('q0', {'q0':'0'})
'$\\\\left|q0\\\\right\\\\rangle=\\\\left|0\\\\right\\\\rangle$'
"""
init = inits.get(label)
if init:
return r'$\left|%s\right\rangle=\left|%s\right\rangle$' % (label, init)
return r'$\left|%s\right\rangle$' % label
def labeller(n, symbol='q'):
"""Autogenerate labels for wires of quantum circuits.
Parameters
==========
n : int
number of qubits in the circuit.
symbol : string
A character string to precede all gate labels. E.g. 'q_0', 'q_1', etc.
>>> from sympy.physics.quantum.circuitplot import labeller
>>> labeller(2)
['q_1', 'q_0']
>>> labeller(3,'j')
['j_2', 'j_1', 'j_0']
"""
return ['%s_%d' % (symbol,n-i-1) for i in range(n)]
class Mz(OneQubitGate):
"""Mock-up of a z measurement gate.
This is in circuitplot rather than gate.py because it's not a real
gate, it just draws one.
"""
measurement = True
gate_name='Mz'
gate_name_latex='M_z'
class Mx(OneQubitGate):
"""Mock-up of an x measurement gate.
This is in circuitplot rather than gate.py because it's not a real
gate, it just draws one.
"""
measurement = True
gate_name='Mx'
gate_name_latex='M_x'
class CreateOneQubitGate(type):
def __new__(mcl, name, latexname=None):
if not latexname:
latexname = name
return type(name + "Gate", (OneQubitGate,),
{'gate_name': name, 'gate_name_latex': latexname})
def CreateCGate(name, latexname=None):
"""Use a lexical closure to make a controlled gate.
"""
if not latexname:
latexname = name
onequbitgate = CreateOneQubitGate(name, latexname)
def ControlledGate(ctrls,target):
return CGate(tuple(ctrls),onequbitgate(target))
return ControlledGate
PK ]ZZZ����:6 :6 % sympy/physics/quantum/circuitutils.py"""Primitive circuit operations on quantum circuits."""
from functools import reduce
from sympy.core.sorting import default_sort_key
from sympy.core.containers import Tuple
from sympy.core.mul import Mul
from sympy.core.symbol import Symbol
from sympy.core.sympify import sympify
from sympy.utilities import numbered_symbols
from sympy.physics.quantum.gate import Gate
__all__ = [
'kmp_table',
'find_subcircuit',
'replace_subcircuit',
'convert_to_symbolic_indices',
'convert_to_real_indices',
'random_reduce',
'random_insert'
]
def kmp_table(word):
"""Build the 'partial match' table of the Knuth-Morris-Pratt algorithm.
Note: This is applicable to strings or
quantum circuits represented as tuples.
"""
# Current position in subcircuit
pos = 2
# Beginning position of candidate substring that
# may reappear later in word
cnd = 0
# The 'partial match' table that helps one determine
# the next location to start substring search
table = []
table.append(-1)
table.append(0)
while pos < len(word):
if word[pos - 1] == word[cnd]:
cnd = cnd + 1
table.append(cnd)
pos = pos + 1
elif cnd > 0:
cnd = table[cnd]
else:
table.append(0)
pos = pos + 1
return table
def find_subcircuit(circuit, subcircuit, start=0, end=0):
"""Finds the subcircuit in circuit, if it exists.
Explanation
===========
If the subcircuit exists, the index of the start of
the subcircuit in circuit is returned; otherwise,
-1 is returned. The algorithm that is implemented
is the Knuth-Morris-Pratt algorithm.
Parameters
==========
circuit : tuple, Gate or Mul
A tuple of Gates or Mul representing a quantum circuit
subcircuit : tuple, Gate or Mul
A tuple of Gates or Mul to find in circuit
start : int
The location to start looking for subcircuit.
If start is the same or past end, -1 is returned.
end : int
The last place to look for a subcircuit. If end
is less than 1 (one), then the length of circuit
is taken to be end.
Examples
========
Find the first instance of a subcircuit:
>>> from sympy.physics.quantum.circuitutils import find_subcircuit
>>> from sympy.physics.quantum.gate import X, Y, Z, H
>>> circuit = X(0)*Z(0)*Y(0)*H(0)
>>> subcircuit = Z(0)*Y(0)
>>> find_subcircuit(circuit, subcircuit)
1
Find the first instance starting at a specific position:
>>> find_subcircuit(circuit, subcircuit, start=1)
1
>>> find_subcircuit(circuit, subcircuit, start=2)
-1
>>> circuit = circuit*subcircuit
>>> find_subcircuit(circuit, subcircuit, start=2)
4
Find the subcircuit within some interval:
>>> find_subcircuit(circuit, subcircuit, start=2, end=2)
-1
"""
if isinstance(circuit, Mul):
circuit = circuit.args
if isinstance(subcircuit, Mul):
subcircuit = subcircuit.args
if len(subcircuit) == 0 or len(subcircuit) > len(circuit):
return -1
if end < 1:
end = len(circuit)
# Location in circuit
pos = start
# Location in the subcircuit
index = 0
# 'Partial match' table
table = kmp_table(subcircuit)
while (pos + index) < end:
if subcircuit[index] == circuit[pos + index]:
index = index + 1
else:
pos = pos + index - table[index]
index = table[index] if table[index] > -1 else 0
if index == len(subcircuit):
return pos
return -1
def replace_subcircuit(circuit, subcircuit, replace=None, pos=0):
"""Replaces a subcircuit with another subcircuit in circuit,
if it exists.
Explanation
===========
If multiple instances of subcircuit exists, the first instance is
replaced. The position to being searching from (if different from
0) may be optionally given. If subcircuit cannot be found, circuit
is returned.
Parameters
==========
circuit : tuple, Gate or Mul
A quantum circuit.
subcircuit : tuple, Gate or Mul
The circuit to be replaced.
replace : tuple, Gate or Mul
The replacement circuit.
pos : int
The location to start search and replace
subcircuit, if it exists. This may be used
if it is known beforehand that multiple
instances exist, and it is desirable to
replace a specific instance. If a negative number
is given, pos will be defaulted to 0.
Examples
========
Find and remove the subcircuit:
>>> from sympy.physics.quantum.circuitutils import replace_subcircuit
>>> from sympy.physics.quantum.gate import X, Y, Z, H
>>> circuit = X(0)*Z(0)*Y(0)*H(0)*X(0)*H(0)*Y(0)
>>> subcircuit = Z(0)*Y(0)
>>> replace_subcircuit(circuit, subcircuit)
(X(0), H(0), X(0), H(0), Y(0))
Remove the subcircuit given a starting search point:
>>> replace_subcircuit(circuit, subcircuit, pos=1)
(X(0), H(0), X(0), H(0), Y(0))
>>> replace_subcircuit(circuit, subcircuit, pos=2)
(X(0), Z(0), Y(0), H(0), X(0), H(0), Y(0))
Replace the subcircuit:
>>> replacement = H(0)*Z(0)
>>> replace_subcircuit(circuit, subcircuit, replace=replacement)
(X(0), H(0), Z(0), H(0), X(0), H(0), Y(0))
"""
if pos < 0:
pos = 0
if isinstance(circuit, Mul):
circuit = circuit.args
if isinstance(subcircuit, Mul):
subcircuit = subcircuit.args
if isinstance(replace, Mul):
replace = replace.args
elif replace is None:
replace = ()
# Look for the subcircuit starting at pos
loc = find_subcircuit(circuit, subcircuit, start=pos)
# If subcircuit was found
if loc > -1:
# Get the gates to the left of subcircuit
left = circuit[0:loc]
# Get the gates to the right of subcircuit
right = circuit[loc + len(subcircuit):len(circuit)]
# Recombine the left and right side gates into a circuit
circuit = left + replace + right
return circuit
def _sympify_qubit_map(mapping):
new_map = {}
for key in mapping:
new_map[key] = sympify(mapping[key])
return new_map
def convert_to_symbolic_indices(seq, start=None, gen=None, qubit_map=None):
"""Returns the circuit with symbolic indices and the
dictionary mapping symbolic indices to real indices.
The mapping is 1 to 1 and onto (bijective).
Parameters
==========
seq : tuple, Gate/Integer/tuple or Mul
A tuple of Gate, Integer, or tuple objects, or a Mul
start : Symbol
An optional starting symbolic index
gen : object
An optional numbered symbol generator
qubit_map : dict
An existing mapping of symbolic indices to real indices
All symbolic indices have the format 'i#', where # is
some number >= 0.
"""
if isinstance(seq, Mul):
seq = seq.args
# A numbered symbol generator
index_gen = numbered_symbols(prefix='i', start=-1)
cur_ndx = next(index_gen)
# keys are symbolic indices; values are real indices
ndx_map = {}
def create_inverse_map(symb_to_real_map):
rev_items = lambda item: (item[1], item[0])
return dict(map(rev_items, symb_to_real_map.items()))
if start is not None:
if not isinstance(start, Symbol):
msg = 'Expected Symbol for starting index, got %r.' % start
raise TypeError(msg)
cur_ndx = start
if gen is not None:
if not isinstance(gen, numbered_symbols().__class__):
msg = 'Expected a generator, got %r.' % gen
raise TypeError(msg)
index_gen = gen
if qubit_map is not None:
if not isinstance(qubit_map, dict):
msg = ('Expected dict for existing map, got ' +
'%r.' % qubit_map)
raise TypeError(msg)
ndx_map = qubit_map
ndx_map = _sympify_qubit_map(ndx_map)
# keys are real indices; keys are symbolic indices
inv_map = create_inverse_map(ndx_map)
sym_seq = ()
for item in seq:
# Nested items, so recurse
if isinstance(item, Gate):
result = convert_to_symbolic_indices(item.args,
qubit_map=ndx_map,
start=cur_ndx,
gen=index_gen)
sym_item, new_map, cur_ndx, index_gen = result
ndx_map.update(new_map)
inv_map = create_inverse_map(ndx_map)
elif isinstance(item, (tuple, Tuple)):
result = convert_to_symbolic_indices(item,
qubit_map=ndx_map,
start=cur_ndx,
gen=index_gen)
sym_item, new_map, cur_ndx, index_gen = result
ndx_map.update(new_map)
inv_map = create_inverse_map(ndx_map)
elif item in inv_map:
sym_item = inv_map[item]
else:
cur_ndx = next(gen)
ndx_map[cur_ndx] = item
inv_map[item] = cur_ndx
sym_item = cur_ndx
if isinstance(item, Gate):
sym_item = item.__class__(*sym_item)
sym_seq = sym_seq + (sym_item,)
return sym_seq, ndx_map, cur_ndx, index_gen
def convert_to_real_indices(seq, qubit_map):
"""Returns the circuit with real indices.
Parameters
==========
seq : tuple, Gate/Integer/tuple or Mul
A tuple of Gate, Integer, or tuple objects or a Mul
qubit_map : dict
A dictionary mapping symbolic indices to real indices.
Examples
========
Change the symbolic indices to real integers:
>>> from sympy import symbols
>>> from sympy.physics.quantum.circuitutils import convert_to_real_indices
>>> from sympy.physics.quantum.gate import X, Y, H
>>> i0, i1 = symbols('i:2')
>>> index_map = {i0 : 0, i1 : 1}
>>> convert_to_real_indices(X(i0)*Y(i1)*H(i0)*X(i1), index_map)
(X(0), Y(1), H(0), X(1))
"""
if isinstance(seq, Mul):
seq = seq.args
if not isinstance(qubit_map, dict):
msg = 'Expected dict for qubit_map, got %r.' % qubit_map
raise TypeError(msg)
qubit_map = _sympify_qubit_map(qubit_map)
real_seq = ()
for item in seq:
# Nested items, so recurse
if isinstance(item, Gate):
real_item = convert_to_real_indices(item.args, qubit_map)
elif isinstance(item, (tuple, Tuple)):
real_item = convert_to_real_indices(item, qubit_map)
else:
real_item = qubit_map[item]
if isinstance(item, Gate):
real_item = item.__class__(*real_item)
real_seq = real_seq + (real_item,)
return real_seq
def random_reduce(circuit, gate_ids, seed=None):
"""Shorten the length of a quantum circuit.
Explanation
===========
random_reduce looks for circuit identities in circuit, randomly chooses
one to remove, and returns a shorter yet equivalent circuit. If no
identities are found, the same circuit is returned.
Parameters
==========
circuit : Gate tuple of Mul
A tuple of Gates representing a quantum circuit
gate_ids : list, GateIdentity
List of gate identities to find in circuit
seed : int or list
seed used for _randrange; to override the random selection, provide a
list of integers: the elements of gate_ids will be tested in the order
given by the list
"""
from sympy.core.random import _randrange
if not gate_ids:
return circuit
if isinstance(circuit, Mul):
circuit = circuit.args
ids = flatten_ids(gate_ids)
# Create the random integer generator with the seed
randrange = _randrange(seed)
# Look for an identity in the circuit
while ids:
i = randrange(len(ids))
id = ids.pop(i)
if find_subcircuit(circuit, id) != -1:
break
else:
# no identity was found
return circuit
# return circuit with the identity removed
return replace_subcircuit(circuit, id)
def random_insert(circuit, choices, seed=None):
"""Insert a circuit into another quantum circuit.
Explanation
===========
random_insert randomly chooses a location in the circuit to insert
a randomly selected circuit from amongst the given choices.
Parameters
==========
circuit : Gate tuple or Mul
A tuple or Mul of Gates representing a quantum circuit
choices : list
Set of circuit choices
seed : int or list
seed used for _randrange; to override the random selections, give
a list two integers, [i, j] where i is the circuit location where
choice[j] will be inserted.
Notes
=====
Indices for insertion should be [0, n] if n is the length of the
circuit.
"""
from sympy.core.random import _randrange
if not choices:
return circuit
if isinstance(circuit, Mul):
circuit = circuit.args
# get the location in the circuit and the element to insert from choices
randrange = _randrange(seed)
loc = randrange(len(circuit) + 1)
choice = choices[randrange(len(choices))]
circuit = list(circuit)
circuit[loc: loc] = choice
return tuple(circuit)
# Flatten the GateIdentity objects (with gate rules) into one single list
def flatten_ids(ids):
collapse = lambda acc, an_id: acc + sorted(an_id.equivalent_ids,
key=default_sort_key)
ids = reduce(collapse, ids, [])
ids.sort(key=default_sort_key)
return ids
PK ]ZZZ?���a a # sympy/physics/quantum/commutator.py"""The commutator: [A,B] = A*B - B*A."""
from sympy.core.add import Add
from sympy.core.expr import Expr
from sympy.core.mul import Mul
from sympy.core.power import Pow
from sympy.core.singleton import S
from sympy.printing.pretty.stringpict import prettyForm
from sympy.physics.quantum.dagger import Dagger
from sympy.physics.quantum.operator import Operator
__all__ = [
'Commutator'
]
#-----------------------------------------------------------------------------
# Commutator
#-----------------------------------------------------------------------------
class Commutator(Expr):
"""The standard commutator, in an unevaluated state.
Explanation
===========
Evaluating a commutator is defined [1]_ as: ``[A, B] = A*B - B*A``. This
class returns the commutator in an unevaluated form. To evaluate the
commutator, use the ``.doit()`` method.
Canonical ordering of a commutator is ``[A, B]`` for ``A < B``. The
arguments of the commutator are put into canonical order using ``__cmp__``.
If ``B < A``, then ``[B, A]`` is returned as ``-[A, B]``.
Parameters
==========
A : Expr
The first argument of the commutator [A,B].
B : Expr
The second argument of the commutator [A,B].
Examples
========
>>> from sympy.physics.quantum import Commutator, Dagger, Operator
>>> from sympy.abc import x, y
>>> A = Operator('A')
>>> B = Operator('B')
>>> C = Operator('C')
Create a commutator and use ``.doit()`` to evaluate it:
>>> comm = Commutator(A, B)
>>> comm
[A,B]
>>> comm.doit()
A*B - B*A
The commutator orders it arguments in canonical order:
>>> comm = Commutator(B, A); comm
-[A,B]
Commutative constants are factored out:
>>> Commutator(3*x*A, x*y*B)
3*x**2*y*[A,B]
Using ``.expand(commutator=True)``, the standard commutator expansion rules
can be applied:
>>> Commutator(A+B, C).expand(commutator=True)
[A,C] + [B,C]
>>> Commutator(A, B+C).expand(commutator=True)
[A,B] + [A,C]
>>> Commutator(A*B, C).expand(commutator=True)
[A,C]*B + A*[B,C]
>>> Commutator(A, B*C).expand(commutator=True)
[A,B]*C + B*[A,C]
Adjoint operations applied to the commutator are properly applied to the
arguments:
>>> Dagger(Commutator(A, B))
-[Dagger(A),Dagger(B)]
References
==========
.. [1] https://en.wikipedia.org/wiki/Commutator
"""
is_commutative = False
def __new__(cls, A, B):
r = cls.eval(A, B)
if r is not None:
return r
obj = Expr.__new__(cls, A, B)
return obj
@classmethod
def eval(cls, a, b):
if not (a and b):
return S.Zero
if a == b:
return S.Zero
if a.is_commutative or b.is_commutative:
return S.Zero
# [xA,yB] -> xy*[A,B]
ca, nca = a.args_cnc()
cb, ncb = b.args_cnc()
c_part = ca + cb
if c_part:
return Mul(Mul(*c_part), cls(Mul._from_args(nca), Mul._from_args(ncb)))
# Canonical ordering of arguments
# The Commutator [A, B] is in canonical form if A < B.
if a.compare(b) == 1:
return S.NegativeOne*cls(b, a)
def _expand_pow(self, A, B, sign):
exp = A.exp
if not exp.is_integer or not exp.is_constant() or abs(exp) <= 1:
# nothing to do
return self
base = A.base
if exp.is_negative:
base = A.base**-1
exp = -exp
comm = Commutator(base, B).expand(commutator=True)
result = base**(exp - 1) * comm
for i in range(1, exp):
result += base**(exp - 1 - i) * comm * base**i
return sign*result.expand()
def _eval_expand_commutator(self, **hints):
A = self.args[0]
B = self.args[1]
if isinstance(A, Add):
# [A + B, C] -> [A, C] + [B, C]
sargs = []
for term in A.args:
comm = Commutator(term, B)
if isinstance(comm, Commutator):
comm = comm._eval_expand_commutator()
sargs.append(comm)
return Add(*sargs)
elif isinstance(B, Add):
# [A, B + C] -> [A, B] + [A, C]
sargs = []
for term in B.args:
comm = Commutator(A, term)
if isinstance(comm, Commutator):
comm = comm._eval_expand_commutator()
sargs.append(comm)
return Add(*sargs)
elif isinstance(A, Mul):
# [A*B, C] -> A*[B, C] + [A, C]*B
a = A.args[0]
b = Mul(*A.args[1:])
c = B
comm1 = Commutator(b, c)
comm2 = Commutator(a, c)
if isinstance(comm1, Commutator):
comm1 = comm1._eval_expand_commutator()
if isinstance(comm2, Commutator):
comm2 = comm2._eval_expand_commutator()
first = Mul(a, comm1)
second = Mul(comm2, b)
return Add(first, second)
elif isinstance(B, Mul):
# [A, B*C] -> [A, B]*C + B*[A, C]
a = A
b = B.args[0]
c = Mul(*B.args[1:])
comm1 = Commutator(a, b)
comm2 = Commutator(a, c)
if isinstance(comm1, Commutator):
comm1 = comm1._eval_expand_commutator()
if isinstance(comm2, Commutator):
comm2 = comm2._eval_expand_commutator()
first = Mul(comm1, c)
second = Mul(b, comm2)
return Add(first, second)
elif isinstance(A, Pow):
# [A**n, C] -> A**(n - 1)*[A, C] + A**(n - 2)*[A, C]*A + ... + [A, C]*A**(n-1)
return self._expand_pow(A, B, 1)
elif isinstance(B, Pow):
# [A, C**n] -> C**(n - 1)*[C, A] + C**(n - 2)*[C, A]*C + ... + [C, A]*C**(n-1)
return self._expand_pow(B, A, -1)
# No changes, so return self
return self
def doit(self, **hints):
""" Evaluate commutator """
A = self.args[0]
B = self.args[1]
if isinstance(A, Operator) and isinstance(B, Operator):
try:
comm = A._eval_commutator(B, **hints)
except NotImplementedError:
try:
comm = -1*B._eval_commutator(A, **hints)
except NotImplementedError:
comm = None
if comm is not None:
return comm.doit(**hints)
return (A*B - B*A).doit(**hints)
def _eval_adjoint(self):
return Commutator(Dagger(self.args[1]), Dagger(self.args[0]))
def _sympyrepr(self, printer, *args):
return "%s(%s,%s)" % (
self.__class__.__name__, printer._print(
self.args[0]), printer._print(self.args[1])
)
def _sympystr(self, printer, *args):
return "[%s,%s]" % (
printer._print(self.args[0]), printer._print(self.args[1]))
def _pretty(self, printer, *args):
pform = printer._print(self.args[0], *args)
pform = prettyForm(*pform.right(prettyForm(',')))
pform = prettyForm(*pform.right(printer._print(self.args[1], *args)))
pform = prettyForm(*pform.parens(left='[', right=']'))
return pform
def _latex(self, printer, *args):
return "\\left[%s,%s\\right]" % tuple([
printer._print(arg, *args) for arg in self.args])
PK ]ZZZ�x��� � " sympy/physics/quantum/constants.py"""Constants (like hbar) related to quantum mechanics."""
from sympy.core.numbers import NumberSymbol
from sympy.core.singleton import Singleton
from sympy.printing.pretty.stringpict import prettyForm
import mpmath.libmp as mlib
#-----------------------------------------------------------------------------
# Constants
#-----------------------------------------------------------------------------
__all__ = [
'hbar',
'HBar',
]
class HBar(NumberSymbol, metaclass=Singleton):
"""Reduced Plank's constant in numerical and symbolic form [1]_.
Examples
========
>>> from sympy.physics.quantum.constants import hbar
>>> hbar.evalf()
1.05457162000000e-34
References
==========
.. [1] https://en.wikipedia.org/wiki/Planck_constant
"""
is_real = True
is_positive = True
is_negative = False
is_irrational = True
__slots__ = ()
def _as_mpf_val(self, prec):
return mlib.from_float(1.05457162e-34, prec)
def _sympyrepr(self, printer, *args):
return 'HBar()'
def _sympystr(self, printer, *args):
return 'hbar'
def _pretty(self, printer, *args):
if printer._use_unicode:
return prettyForm('\N{PLANCK CONSTANT OVER TWO PI}')
return prettyForm('hbar')
def _latex(self, printer, *args):
return r'\hbar'
# Create an instance for everyone to use.
hbar = HBar()
PK ]ZZZ
�)� � sympy/physics/quantum/dagger.py"""Hermitian conjugation."""
from sympy.core import Expr, Mul, sympify
from sympy.functions.elementary.complexes import adjoint
__all__ = [
'Dagger'
]
class Dagger(adjoint):
"""General Hermitian conjugate operation.
Explanation
===========
Take the Hermetian conjugate of an argument [1]_. For matrices this
operation is equivalent to transpose and complex conjugate [2]_.
Parameters
==========
arg : Expr
The SymPy expression that we want to take the dagger of.
evaluate : bool
Whether the resulting expression should be directly evaluated.
Examples
========
Daggering various quantum objects:
>>> from sympy.physics.quantum.dagger import Dagger
>>> from sympy.physics.quantum.state import Ket, Bra
>>> from sympy.physics.quantum.operator import Operator
>>> Dagger(Ket('psi'))
<psi|
>>> Dagger(Bra('phi'))
|phi>
>>> Dagger(Operator('A'))
Dagger(A)
Inner and outer products::
>>> from sympy.physics.quantum import InnerProduct, OuterProduct
>>> Dagger(InnerProduct(Bra('a'), Ket('b')))
<b|a>
>>> Dagger(OuterProduct(Ket('a'), Bra('b')))
|b><a|
Powers, sums and products::
>>> A = Operator('A')
>>> B = Operator('B')
>>> Dagger(A*B)
Dagger(B)*Dagger(A)
>>> Dagger(A+B)
Dagger(A) + Dagger(B)
>>> Dagger(A**2)
Dagger(A)**2
Dagger also seamlessly handles complex numbers and matrices::
>>> from sympy import Matrix, I
>>> m = Matrix([[1,I],[2,I]])
>>> m
Matrix([
[1, I],
[2, I]])
>>> Dagger(m)
Matrix([
[ 1, 2],
[-I, -I]])
References
==========
.. [1] https://en.wikipedia.org/wiki/Hermitian_adjoint
.. [2] https://en.wikipedia.org/wiki/Hermitian_transpose
"""
def __new__(cls, arg, evaluate=True):
if hasattr(arg, 'adjoint') and evaluate:
return arg.adjoint()
elif hasattr(arg, 'conjugate') and hasattr(arg, 'transpose') and evaluate:
return arg.conjugate().transpose()
return Expr.__new__(cls, sympify(arg))
def __mul__(self, other):
from sympy.physics.quantum import IdentityOperator
if isinstance(other, IdentityOperator):
return self
return Mul(self, other)
adjoint.__name__ = "Dagger"
adjoint._sympyrepr = lambda a, b: "Dagger(%s)" % b._print(a.args[0])
PK ]ZZZG�& & sympy/physics/quantum/density.pyfrom itertools import product
from sympy.core.add import Add
from sympy.core.containers import Tuple
from sympy.core.function import expand
from sympy.core.mul import Mul
from sympy.core.singleton import S
from sympy.functions.elementary.exponential import log
from sympy.matrices.dense import MutableDenseMatrix as Matrix
from sympy.printing.pretty.stringpict import prettyForm
from sympy.physics.quantum.dagger import Dagger
from sympy.physics.quantum.operator import HermitianOperator
from sympy.physics.quantum.represent import represent
from sympy.physics.quantum.matrixutils import numpy_ndarray, scipy_sparse_matrix, to_numpy
from sympy.physics.quantum.tensorproduct import TensorProduct, tensor_product_simp
from sympy.physics.quantum.trace import Tr
class Density(HermitianOperator):
"""Density operator for representing mixed states.
TODO: Density operator support for Qubits
Parameters
==========
values : tuples/lists
Each tuple/list should be of form (state, prob) or [state,prob]
Examples
========
Create a density operator with 2 states represented by Kets.
>>> from sympy.physics.quantum.state import Ket
>>> from sympy.physics.quantum.density import Density
>>> d = Density([Ket(0), 0.5], [Ket(1),0.5])
>>> d
Density((|0>, 0.5),(|1>, 0.5))
"""
@classmethod
def _eval_args(cls, args):
# call this to qsympify the args
args = super()._eval_args(args)
for arg in args:
# Check if arg is a tuple
if not (isinstance(arg, Tuple) and len(arg) == 2):
raise ValueError("Each argument should be of form [state,prob]"
" or ( state, prob )")
return args
def states(self):
"""Return list of all states.
Examples
========
>>> from sympy.physics.quantum.state import Ket
>>> from sympy.physics.quantum.density import Density
>>> d = Density([Ket(0), 0.5], [Ket(1),0.5])
>>> d.states()
(|0>, |1>)
"""
return Tuple(*[arg[0] for arg in self.args])
def probs(self):
"""Return list of all probabilities.
Examples
========
>>> from sympy.physics.quantum.state import Ket
>>> from sympy.physics.quantum.density import Density
>>> d = Density([Ket(0), 0.5], [Ket(1),0.5])
>>> d.probs()
(0.5, 0.5)
"""
return Tuple(*[arg[1] for arg in self.args])
def get_state(self, index):
"""Return specific state by index.
Parameters
==========
index : index of state to be returned
Examples
========
>>> from sympy.physics.quantum.state import Ket
>>> from sympy.physics.quantum.density import Density
>>> d = Density([Ket(0), 0.5], [Ket(1),0.5])
>>> d.states()[1]
|1>
"""
state = self.args[index][0]
return state
def get_prob(self, index):
"""Return probability of specific state by index.
Parameters
===========
index : index of states whose probability is returned.
Examples
========
>>> from sympy.physics.quantum.state import Ket
>>> from sympy.physics.quantum.density import Density
>>> d = Density([Ket(0), 0.5], [Ket(1),0.5])
>>> d.probs()[1]
0.500000000000000
"""
prob = self.args[index][1]
return prob
def apply_op(self, op):
"""op will operate on each individual state.
Parameters
==========
op : Operator
Examples
========
>>> from sympy.physics.quantum.state import Ket
>>> from sympy.physics.quantum.density import Density
>>> from sympy.physics.quantum.operator import Operator
>>> A = Operator('A')
>>> d = Density([Ket(0), 0.5], [Ket(1),0.5])
>>> d.apply_op(A)
Density((A*|0>, 0.5),(A*|1>, 0.5))
"""
new_args = [(op*state, prob) for (state, prob) in self.args]
return Density(*new_args)
def doit(self, **hints):
"""Expand the density operator into an outer product format.
Examples
========
>>> from sympy.physics.quantum.state import Ket
>>> from sympy.physics.quantum.density import Density
>>> from sympy.physics.quantum.operator import Operator
>>> A = Operator('A')
>>> d = Density([Ket(0), 0.5], [Ket(1),0.5])
>>> d.doit()
0.5*|0><0| + 0.5*|1><1|
"""
terms = []
for (state, prob) in self.args:
state = state.expand() # needed to break up (a+b)*c
if (isinstance(state, Add)):
for arg in product(state.args, repeat=2):
terms.append(prob*self._generate_outer_prod(arg[0],
arg[1]))
else:
terms.append(prob*self._generate_outer_prod(state, state))
return Add(*terms)
def _generate_outer_prod(self, arg1, arg2):
c_part1, nc_part1 = arg1.args_cnc()
c_part2, nc_part2 = arg2.args_cnc()
if (len(nc_part1) == 0 or len(nc_part2) == 0):
raise ValueError('Atleast one-pair of'
' Non-commutative instance required'
' for outer product.')
# Muls of Tensor Products should be expanded
# before this function is called
if (isinstance(nc_part1[0], TensorProduct) and len(nc_part1) == 1
and len(nc_part2) == 1):
op = tensor_product_simp(nc_part1[0]*Dagger(nc_part2[0]))
else:
op = Mul(*nc_part1)*Dagger(Mul(*nc_part2))
return Mul(*c_part1)*Mul(*c_part2) * op
def _represent(self, **options):
return represent(self.doit(), **options)
def _print_operator_name_latex(self, printer, *args):
return r'\rho'
def _print_operator_name_pretty(self, printer, *args):
return prettyForm('\N{GREEK SMALL LETTER RHO}')
def _eval_trace(self, **kwargs):
indices = kwargs.get('indices', [])
return Tr(self.doit(), indices).doit()
def entropy(self):
""" Compute the entropy of a density matrix.
Refer to density.entropy() method for examples.
"""
return entropy(self)
def entropy(density):
"""Compute the entropy of a matrix/density object.
This computes -Tr(density*ln(density)) using the eigenvalue decomposition
of density, which is given as either a Density instance or a matrix
(numpy.ndarray, sympy.Matrix or scipy.sparse).
Parameters
==========
density : density matrix of type Density, SymPy matrix,
scipy.sparse or numpy.ndarray
Examples
========
>>> from sympy.physics.quantum.density import Density, entropy
>>> from sympy.physics.quantum.spin import JzKet
>>> from sympy import S
>>> up = JzKet(S(1)/2,S(1)/2)
>>> down = JzKet(S(1)/2,-S(1)/2)
>>> d = Density((up,S(1)/2),(down,S(1)/2))
>>> entropy(d)
log(2)/2
"""
if isinstance(density, Density):
density = represent(density) # represent in Matrix
if isinstance(density, scipy_sparse_matrix):
density = to_numpy(density)
if isinstance(density, Matrix):
eigvals = density.eigenvals().keys()
return expand(-sum(e*log(e) for e in eigvals))
elif isinstance(density, numpy_ndarray):
import numpy as np
eigvals = np.linalg.eigvals(density)
return -np.sum(eigvals*np.log(eigvals))
else:
raise ValueError(
"numpy.ndarray, scipy.sparse or SymPy matrix expected")
def fidelity(state1, state2):
""" Computes the fidelity [1]_ between two quantum states
The arguments provided to this function should be a square matrix or a
Density object. If it is a square matrix, it is assumed to be diagonalizable.
Parameters
==========
state1, state2 : a density matrix or Matrix
Examples
========
>>> from sympy import S, sqrt
>>> from sympy.physics.quantum.dagger import Dagger
>>> from sympy.physics.quantum.spin import JzKet
>>> from sympy.physics.quantum.density import fidelity
>>> from sympy.physics.quantum.represent import represent
>>>
>>> up = JzKet(S(1)/2,S(1)/2)
>>> down = JzKet(S(1)/2,-S(1)/2)
>>> amp = 1/sqrt(2)
>>> updown = (amp*up) + (amp*down)
>>>
>>> # represent turns Kets into matrices
>>> up_dm = represent(up*Dagger(up))
>>> down_dm = represent(down*Dagger(down))
>>> updown_dm = represent(updown*Dagger(updown))
>>>
>>> fidelity(up_dm, up_dm)
1
>>> fidelity(up_dm, down_dm) #orthogonal states
0
>>> fidelity(up_dm, updown_dm).evalf().round(3)
0.707
References
==========
.. [1] https://en.wikipedia.org/wiki/Fidelity_of_quantum_states
"""
state1 = represent(state1) if isinstance(state1, Density) else state1
state2 = represent(state2) if isinstance(state2, Density) else state2
if not isinstance(state1, Matrix) or not isinstance(state2, Matrix):
raise ValueError("state1 and state2 must be of type Density or Matrix "
"received type=%s for state1 and type=%s for state2" %
(type(state1), type(state2)))
if state1.shape != state2.shape and state1.is_square:
raise ValueError("The dimensions of both args should be equal and the "
"matrix obtained should be a square matrix")
sqrt_state1 = state1**S.Half
return Tr((sqrt_state1*state2*sqrt_state1)**S.Half).doit()
PK ]ZZZ��e�w w sympy/physics/quantum/fermion.py"""Fermionic quantum operators."""
from sympy.core.numbers import Integer
from sympy.core.singleton import S
from sympy.physics.quantum import Operator
from sympy.physics.quantum import HilbertSpace, Ket, Bra
from sympy.functions.special.tensor_functions import KroneckerDelta
__all__ = [
'FermionOp',
'FermionFockKet',
'FermionFockBra'
]
class FermionOp(Operator):
"""A fermionic operator that satisfies {c, Dagger(c)} == 1.
Parameters
==========
name : str
A string that labels the fermionic mode.
annihilation : bool
A bool that indicates if the fermionic operator is an annihilation
(True, default value) or creation operator (False)
Examples
========
>>> from sympy.physics.quantum import Dagger, AntiCommutator
>>> from sympy.physics.quantum.fermion import FermionOp
>>> c = FermionOp("c")
>>> AntiCommutator(c, Dagger(c)).doit()
1
"""
@property
def name(self):
return self.args[0]
@property
def is_annihilation(self):
return bool(self.args[1])
@classmethod
def default_args(self):
return ("c", True)
def __new__(cls, *args, **hints):
if not len(args) in [1, 2]:
raise ValueError('1 or 2 parameters expected, got %s' % args)
if len(args) == 1:
args = (args[0], S.One)
if len(args) == 2:
args = (args[0], Integer(args[1]))
return Operator.__new__(cls, *args)
def _eval_commutator_FermionOp(self, other, **hints):
if 'independent' in hints and hints['independent']:
# [c, d] = 0
return S.Zero
return None
def _eval_anticommutator_FermionOp(self, other, **hints):
if self.name == other.name:
# {a^\dagger, a} = 1
if not self.is_annihilation and other.is_annihilation:
return S.One
elif 'independent' in hints and hints['independent']:
# {c, d} = 2 * c * d, because [c, d] = 0 for independent operators
return 2 * self * other
return None
def _eval_anticommutator_BosonOp(self, other, **hints):
# because fermions and bosons commute
return 2 * self * other
def _eval_commutator_BosonOp(self, other, **hints):
return S.Zero
def _eval_adjoint(self):
return FermionOp(str(self.name), not self.is_annihilation)
def _print_contents_latex(self, printer, *args):
if self.is_annihilation:
return r'{%s}' % str(self.name)
else:
return r'{{%s}^\dagger}' % str(self.name)
def _print_contents(self, printer, *args):
if self.is_annihilation:
return r'%s' % str(self.name)
else:
return r'Dagger(%s)' % str(self.name)
def _print_contents_pretty(self, printer, *args):
from sympy.printing.pretty.stringpict import prettyForm
pform = printer._print(self.args[0], *args)
if self.is_annihilation:
return pform
else:
return pform**prettyForm('\N{DAGGER}')
def _eval_power(self, exp):
from sympy.core.singleton import S
if exp == 0:
return S.One
elif exp == 1:
return self
elif (exp > 1) == True and exp.is_integer == True:
return S.Zero
elif (exp < 0) == True or exp.is_integer == False:
raise ValueError("Fermionic operators can only be raised to a"
" positive integer power")
return Operator._eval_power(self, exp)
class FermionFockKet(Ket):
"""Fock state ket for a fermionic mode.
Parameters
==========
n : Number
The Fock state number.
"""
def __new__(cls, n):
if n not in (0, 1):
raise ValueError("n must be 0 or 1")
return Ket.__new__(cls, n)
@property
def n(self):
return self.label[0]
@classmethod
def dual_class(self):
return FermionFockBra
@classmethod
def _eval_hilbert_space(cls, label):
return HilbertSpace()
def _eval_innerproduct_FermionFockBra(self, bra, **hints):
return KroneckerDelta(self.n, bra.n)
def _apply_from_right_to_FermionOp(self, op, **options):
if op.is_annihilation:
if self.n == 1:
return FermionFockKet(0)
else:
return S.Zero
else:
if self.n == 0:
return FermionFockKet(1)
else:
return S.Zero
class FermionFockBra(Bra):
"""Fock state bra for a fermionic mode.
Parameters
==========
n : Number
The Fock state number.
"""
def __new__(cls, n):
if n not in (0, 1):
raise ValueError("n must be 0 or 1")
return Bra.__new__(cls, n)
@property
def n(self):
return self.label[0]
@classmethod
def dual_class(self):
return FermionFockKet
PK ]ZZZ6l��\� \� sympy/physics/quantum/gate.py"""An implementation of gates that act on qubits.
Gates are unitary operators that act on the space of qubits.
Medium Term Todo:
* Optimize Gate._apply_operators_Qubit to remove the creation of many
intermediate Qubit objects.
* Add commutation relationships to all operators and use this in gate_sort.
* Fix gate_sort and gate_simp.
* Get multi-target UGates plotting properly.
* Get UGate to work with either sympy/numpy matrices and output either
format. This should also use the matrix slots.
"""
from itertools import chain
import random
from sympy.core.add import Add
from sympy.core.containers import Tuple
from sympy.core.mul import Mul
from sympy.core.numbers import (I, Integer)
from sympy.core.power import Pow
from sympy.core.numbers import Number
from sympy.core.singleton import S as _S
from sympy.core.sorting import default_sort_key
from sympy.core.sympify import _sympify
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.printing.pretty.stringpict import prettyForm, stringPict
from sympy.physics.quantum.anticommutator import AntiCommutator
from sympy.physics.quantum.commutator import Commutator
from sympy.physics.quantum.qexpr import QuantumError
from sympy.physics.quantum.hilbert import ComplexSpace
from sympy.physics.quantum.operator import (UnitaryOperator, Operator,
HermitianOperator)
from sympy.physics.quantum.matrixutils import matrix_tensor_product, matrix_eye
from sympy.physics.quantum.matrixcache import matrix_cache
from sympy.matrices.matrixbase import MatrixBase
from sympy.utilities.iterables import is_sequence
__all__ = [
'Gate',
'CGate',
'UGate',
'OneQubitGate',
'TwoQubitGate',
'IdentityGate',
'HadamardGate',
'XGate',
'YGate',
'ZGate',
'TGate',
'PhaseGate',
'SwapGate',
'CNotGate',
# Aliased gate names
'CNOT',
'SWAP',
'H',
'X',
'Y',
'Z',
'T',
'S',
'Phase',
'normalized',
'gate_sort',
'gate_simp',
'random_circuit',
'CPHASE',
'CGateS',
]
#-----------------------------------------------------------------------------
# Gate Super-Classes
#-----------------------------------------------------------------------------
_normalized = True
def _max(*args, **kwargs):
if "key" not in kwargs:
kwargs["key"] = default_sort_key
return max(*args, **kwargs)
def _min(*args, **kwargs):
if "key" not in kwargs:
kwargs["key"] = default_sort_key
return min(*args, **kwargs)
def normalized(normalize):
r"""Set flag controlling normalization of Hadamard gates by `1/\sqrt{2}`.
This is a global setting that can be used to simplify the look of various
expressions, by leaving off the leading `1/\sqrt{2}` of the Hadamard gate.
Parameters
----------
normalize : bool
Should the Hadamard gate include the `1/\sqrt{2}` normalization factor?
When True, the Hadamard gate will have the `1/\sqrt{2}`. When False, the
Hadamard gate will not have this factor.
"""
global _normalized
_normalized = normalize
def _validate_targets_controls(tandc):
tandc = list(tandc)
# Check for integers
for bit in tandc:
if not bit.is_Integer and not bit.is_Symbol:
raise TypeError('Integer expected, got: %r' % tandc[bit])
# Detect duplicates
if len(set(tandc)) != len(tandc):
raise QuantumError(
'Target/control qubits in a gate cannot be duplicated'
)
class Gate(UnitaryOperator):
"""Non-controlled unitary gate operator that acts on qubits.
This is a general abstract gate that needs to be subclassed to do anything
useful.
Parameters
----------
label : tuple, int
A list of the target qubits (as ints) that the gate will apply to.
Examples
========
"""
_label_separator = ','
gate_name = 'G'
gate_name_latex = 'G'
#-------------------------------------------------------------------------
# Initialization/creation
#-------------------------------------------------------------------------
@classmethod
def _eval_args(cls, args):
args = Tuple(*UnitaryOperator._eval_args(args))
_validate_targets_controls(args)
return args
@classmethod
def _eval_hilbert_space(cls, args):
"""This returns the smallest possible Hilbert space."""
return ComplexSpace(2)**(_max(args) + 1)
#-------------------------------------------------------------------------
# Properties
#-------------------------------------------------------------------------
@property
def nqubits(self):
"""The total number of qubits this gate acts on.
For controlled gate subclasses this includes both target and control
qubits, so that, for examples the CNOT gate acts on 2 qubits.
"""
return len(self.targets)
@property
def min_qubits(self):
"""The minimum number of qubits this gate needs to act on."""
return _max(self.targets) + 1
@property
def targets(self):
"""A tuple of target qubits."""
return self.label
@property
def gate_name_plot(self):
return r'$%s$' % self.gate_name_latex
#-------------------------------------------------------------------------
# Gate methods
#-------------------------------------------------------------------------
def get_target_matrix(self, format='sympy'):
"""The matrix representation of the target part of the gate.
Parameters
----------
format : str
The format string ('sympy','numpy', etc.)
"""
raise NotImplementedError(
'get_target_matrix is not implemented in Gate.')
#-------------------------------------------------------------------------
# Apply
#-------------------------------------------------------------------------
def _apply_operator_IntQubit(self, qubits, **options):
"""Redirect an apply from IntQubit to Qubit"""
return self._apply_operator_Qubit(qubits, **options)
def _apply_operator_Qubit(self, qubits, **options):
"""Apply this gate to a Qubit."""
# Check number of qubits this gate acts on.
if qubits.nqubits < self.min_qubits:
raise QuantumError(
'Gate needs a minimum of %r qubits to act on, got: %r' %
(self.min_qubits, qubits.nqubits)
)
# If the controls are not met, just return
if isinstance(self, CGate):
if not self.eval_controls(qubits):
return qubits
targets = self.targets
target_matrix = self.get_target_matrix(format='sympy')
# Find which column of the target matrix this applies to.
column_index = 0
n = 1
for target in targets:
column_index += n*qubits[target]
n = n << 1
column = target_matrix[:, int(column_index)]
# Now apply each column element to the qubit.
result = 0
for index in range(column.rows):
# TODO: This can be optimized to reduce the number of Qubit
# creations. We should simply manipulate the raw list of qubit
# values and then build the new Qubit object once.
# Make a copy of the incoming qubits.
new_qubit = qubits.__class__(*qubits.args)
# Flip the bits that need to be flipped.
for bit, target in enumerate(targets):
if new_qubit[target] != (index >> bit) & 1:
new_qubit = new_qubit.flip(target)
# The value in that row and column times the flipped-bit qubit
# is the result for that part.
result += column[index]*new_qubit
return result
#-------------------------------------------------------------------------
# Represent
#-------------------------------------------------------------------------
def _represent_default_basis(self, **options):
return self._represent_ZGate(None, **options)
def _represent_ZGate(self, basis, **options):
format = options.get('format', 'sympy')
nqubits = options.get('nqubits', 0)
if nqubits == 0:
raise QuantumError(
'The number of qubits must be given as nqubits.')
# Make sure we have enough qubits for the gate.
if nqubits < self.min_qubits:
raise QuantumError(
'The number of qubits %r is too small for the gate.' % nqubits
)
target_matrix = self.get_target_matrix(format)
targets = self.targets
if isinstance(self, CGate):
controls = self.controls
else:
controls = []
m = represent_zbasis(
controls, targets, target_matrix, nqubits, format
)
return m
#-------------------------------------------------------------------------
# Print methods
#-------------------------------------------------------------------------
def _sympystr(self, printer, *args):
label = self._print_label(printer, *args)
return '%s(%s)' % (self.gate_name, label)
def _pretty(self, printer, *args):
a = stringPict(self.gate_name)
b = self._print_label_pretty(printer, *args)
return self._print_subscript_pretty(a, b)
def _latex(self, printer, *args):
label = self._print_label(printer, *args)
return '%s_{%s}' % (self.gate_name_latex, label)
def plot_gate(self, axes, gate_idx, gate_grid, wire_grid):
raise NotImplementedError('plot_gate is not implemented.')
class CGate(Gate):
"""A general unitary gate with control qubits.
A general control gate applies a target gate to a set of targets if all
of the control qubits have a particular values (set by
``CGate.control_value``).
Parameters
----------
label : tuple
The label in this case has the form (controls, gate), where controls
is a tuple/list of control qubits (as ints) and gate is a ``Gate``
instance that is the target operator.
Examples
========
"""
gate_name = 'C'
gate_name_latex = 'C'
# The values this class controls for.
control_value = _S.One
simplify_cgate = False
#-------------------------------------------------------------------------
# Initialization
#-------------------------------------------------------------------------
@classmethod
def _eval_args(cls, args):
# _eval_args has the right logic for the controls argument.
controls = args[0]
gate = args[1]
if not is_sequence(controls):
controls = (controls,)
controls = UnitaryOperator._eval_args(controls)
_validate_targets_controls(chain(controls, gate.targets))
return (Tuple(*controls), gate)
@classmethod
def _eval_hilbert_space(cls, args):
"""This returns the smallest possible Hilbert space."""
return ComplexSpace(2)**_max(_max(args[0]) + 1, args[1].min_qubits)
#-------------------------------------------------------------------------
# Properties
#-------------------------------------------------------------------------
@property
def nqubits(self):
"""The total number of qubits this gate acts on.
For controlled gate subclasses this includes both target and control
qubits, so that, for examples the CNOT gate acts on 2 qubits.
"""
return len(self.targets) + len(self.controls)
@property
def min_qubits(self):
"""The minimum number of qubits this gate needs to act on."""
return _max(_max(self.controls), _max(self.targets)) + 1
@property
def targets(self):
"""A tuple of target qubits."""
return self.gate.targets
@property
def controls(self):
"""A tuple of control qubits."""
return tuple(self.label[0])
@property
def gate(self):
"""The non-controlled gate that will be applied to the targets."""
return self.label[1]
#-------------------------------------------------------------------------
# Gate methods
#-------------------------------------------------------------------------
def get_target_matrix(self, format='sympy'):
return self.gate.get_target_matrix(format)
def eval_controls(self, qubit):
"""Return True/False to indicate if the controls are satisfied."""
return all(qubit[bit] == self.control_value for bit in self.controls)
def decompose(self, **options):
"""Decompose the controlled gate into CNOT and single qubits gates."""
if len(self.controls) == 1:
c = self.controls[0]
t = self.gate.targets[0]
if isinstance(self.gate, YGate):
g1 = PhaseGate(t)
g2 = CNotGate(c, t)
g3 = PhaseGate(t)
g4 = ZGate(t)
return g1*g2*g3*g4
if isinstance(self.gate, ZGate):
g1 = HadamardGate(t)
g2 = CNotGate(c, t)
g3 = HadamardGate(t)
return g1*g2*g3
else:
return self
#-------------------------------------------------------------------------
# Print methods
#-------------------------------------------------------------------------
def _print_label(self, printer, *args):
controls = self._print_sequence(self.controls, ',', printer, *args)
gate = printer._print(self.gate, *args)
return '(%s),%s' % (controls, gate)
def _pretty(self, printer, *args):
controls = self._print_sequence_pretty(
self.controls, ',', printer, *args)
gate = printer._print(self.gate)
gate_name = stringPict(self.gate_name)
first = self._print_subscript_pretty(gate_name, controls)
gate = self._print_parens_pretty(gate)
final = prettyForm(*first.right(gate))
return final
def _latex(self, printer, *args):
controls = self._print_sequence(self.controls, ',', printer, *args)
gate = printer._print(self.gate, *args)
return r'%s_{%s}{\left(%s\right)}' % \
(self.gate_name_latex, controls, gate)
def plot_gate(self, circ_plot, gate_idx):
"""
Plot the controlled gate. If *simplify_cgate* is true, simplify
C-X and C-Z gates into their more familiar forms.
"""
min_wire = int(_min(chain(self.controls, self.targets)))
max_wire = int(_max(chain(self.controls, self.targets)))
circ_plot.control_line(gate_idx, min_wire, max_wire)
for c in self.controls:
circ_plot.control_point(gate_idx, int(c))
if self.simplify_cgate:
if self.gate.gate_name == 'X':
self.gate.plot_gate_plus(circ_plot, gate_idx)
elif self.gate.gate_name == 'Z':
circ_plot.control_point(gate_idx, self.targets[0])
else:
self.gate.plot_gate(circ_plot, gate_idx)
else:
self.gate.plot_gate(circ_plot, gate_idx)
#-------------------------------------------------------------------------
# Miscellaneous
#-------------------------------------------------------------------------
def _eval_dagger(self):
if isinstance(self.gate, HermitianOperator):
return self
else:
return Gate._eval_dagger(self)
def _eval_inverse(self):
if isinstance(self.gate, HermitianOperator):
return self
else:
return Gate._eval_inverse(self)
def _eval_power(self, exp):
if isinstance(self.gate, HermitianOperator):
if exp == -1:
return Gate._eval_power(self, exp)
elif abs(exp) % 2 == 0:
return self*(Gate._eval_inverse(self))
else:
return self
else:
return Gate._eval_power(self, exp)
class CGateS(CGate):
"""Version of CGate that allows gate simplifications.
I.e. cnot looks like an oplus, cphase has dots, etc.
"""
simplify_cgate=True
class UGate(Gate):
"""General gate specified by a set of targets and a target matrix.
Parameters
----------
label : tuple
A tuple of the form (targets, U), where targets is a tuple of the
target qubits and U is a unitary matrix with dimension of
len(targets).
"""
gate_name = 'U'
gate_name_latex = 'U'
#-------------------------------------------------------------------------
# Initialization
#-------------------------------------------------------------------------
@classmethod
def _eval_args(cls, args):
targets = args[0]
if not is_sequence(targets):
targets = (targets,)
targets = Gate._eval_args(targets)
_validate_targets_controls(targets)
mat = args[1]
if not isinstance(mat, MatrixBase):
raise TypeError('Matrix expected, got: %r' % mat)
#make sure this matrix is of a Basic type
mat = _sympify(mat)
dim = 2**len(targets)
if not all(dim == shape for shape in mat.shape):
raise IndexError(
'Number of targets must match the matrix size: %r %r' %
(targets, mat)
)
return (targets, mat)
@classmethod
def _eval_hilbert_space(cls, args):
"""This returns the smallest possible Hilbert space."""
return ComplexSpace(2)**(_max(args[0]) + 1)
#-------------------------------------------------------------------------
# Properties
#-------------------------------------------------------------------------
@property
def targets(self):
"""A tuple of target qubits."""
return tuple(self.label[0])
#-------------------------------------------------------------------------
# Gate methods
#-------------------------------------------------------------------------
def get_target_matrix(self, format='sympy'):
"""The matrix rep. of the target part of the gate.
Parameters
----------
format : str
The format string ('sympy','numpy', etc.)
"""
return self.label[1]
#-------------------------------------------------------------------------
# Print methods
#-------------------------------------------------------------------------
def _pretty(self, printer, *args):
targets = self._print_sequence_pretty(
self.targets, ',', printer, *args)
gate_name = stringPict(self.gate_name)
return self._print_subscript_pretty(gate_name, targets)
def _latex(self, printer, *args):
targets = self._print_sequence(self.targets, ',', printer, *args)
return r'%s_{%s}' % (self.gate_name_latex, targets)
def plot_gate(self, circ_plot, gate_idx):
circ_plot.one_qubit_box(
self.gate_name_plot,
gate_idx, int(self.targets[0])
)
class OneQubitGate(Gate):
"""A single qubit unitary gate base class."""
nqubits = _S.One
def plot_gate(self, circ_plot, gate_idx):
circ_plot.one_qubit_box(
self.gate_name_plot,
gate_idx, int(self.targets[0])
)
def _eval_commutator(self, other, **hints):
if isinstance(other, OneQubitGate):
if self.targets != other.targets or self.__class__ == other.__class__:
return _S.Zero
return Operator._eval_commutator(self, other, **hints)
def _eval_anticommutator(self, other, **hints):
if isinstance(other, OneQubitGate):
if self.targets != other.targets or self.__class__ == other.__class__:
return Integer(2)*self*other
return Operator._eval_anticommutator(self, other, **hints)
class TwoQubitGate(Gate):
"""A two qubit unitary gate base class."""
nqubits = Integer(2)
#-----------------------------------------------------------------------------
# Single Qubit Gates
#-----------------------------------------------------------------------------
class IdentityGate(OneQubitGate):
"""The single qubit identity gate.
Parameters
----------
target : int
The target qubit this gate will apply to.
Examples
========
"""
is_hermitian = True
gate_name = '1'
gate_name_latex = '1'
# Short cut version of gate._apply_operator_Qubit
def _apply_operator_Qubit(self, qubits, **options):
# Check number of qubits this gate acts on (see gate._apply_operator_Qubit)
if qubits.nqubits < self.min_qubits:
raise QuantumError(
'Gate needs a minimum of %r qubits to act on, got: %r' %
(self.min_qubits, qubits.nqubits)
)
return qubits # no computation required for IdentityGate
def get_target_matrix(self, format='sympy'):
return matrix_cache.get_matrix('eye2', format)
def _eval_commutator(self, other, **hints):
return _S.Zero
def _eval_anticommutator(self, other, **hints):
return Integer(2)*other
class HadamardGate(HermitianOperator, OneQubitGate):
"""The single qubit Hadamard gate.
Parameters
----------
target : int
The target qubit this gate will apply to.
Examples
========
>>> from sympy import sqrt
>>> from sympy.physics.quantum.qubit import Qubit
>>> from sympy.physics.quantum.gate import HadamardGate
>>> from sympy.physics.quantum.qapply import qapply
>>> qapply(HadamardGate(0)*Qubit('1'))
sqrt(2)*|0>/2 - sqrt(2)*|1>/2
>>> # Hadamard on bell state, applied on 2 qubits.
>>> psi = 1/sqrt(2)*(Qubit('00')+Qubit('11'))
>>> qapply(HadamardGate(0)*HadamardGate(1)*psi)
sqrt(2)*|00>/2 + sqrt(2)*|11>/2
"""
gate_name = 'H'
gate_name_latex = 'H'
def get_target_matrix(self, format='sympy'):
if _normalized:
return matrix_cache.get_matrix('H', format)
else:
return matrix_cache.get_matrix('Hsqrt2', format)
def _eval_commutator_XGate(self, other, **hints):
return I*sqrt(2)*YGate(self.targets[0])
def _eval_commutator_YGate(self, other, **hints):
return I*sqrt(2)*(ZGate(self.targets[0]) - XGate(self.targets[0]))
def _eval_commutator_ZGate(self, other, **hints):
return -I*sqrt(2)*YGate(self.targets[0])
def _eval_anticommutator_XGate(self, other, **hints):
return sqrt(2)*IdentityGate(self.targets[0])
def _eval_anticommutator_YGate(self, other, **hints):
return _S.Zero
def _eval_anticommutator_ZGate(self, other, **hints):
return sqrt(2)*IdentityGate(self.targets[0])
class XGate(HermitianOperator, OneQubitGate):
"""The single qubit X, or NOT, gate.
Parameters
----------
target : int
The target qubit this gate will apply to.
Examples
========
"""
gate_name = 'X'
gate_name_latex = 'X'
def get_target_matrix(self, format='sympy'):
return matrix_cache.get_matrix('X', format)
def plot_gate(self, circ_plot, gate_idx):
OneQubitGate.plot_gate(self,circ_plot,gate_idx)
def plot_gate_plus(self, circ_plot, gate_idx):
circ_plot.not_point(
gate_idx, int(self.label[0])
)
def _eval_commutator_YGate(self, other, **hints):
return Integer(2)*I*ZGate(self.targets[0])
def _eval_anticommutator_XGate(self, other, **hints):
return Integer(2)*IdentityGate(self.targets[0])
def _eval_anticommutator_YGate(self, other, **hints):
return _S.Zero
def _eval_anticommutator_ZGate(self, other, **hints):
return _S.Zero
class YGate(HermitianOperator, OneQubitGate):
"""The single qubit Y gate.
Parameters
----------
target : int
The target qubit this gate will apply to.
Examples
========
"""
gate_name = 'Y'
gate_name_latex = 'Y'
def get_target_matrix(self, format='sympy'):
return matrix_cache.get_matrix('Y', format)
def _eval_commutator_ZGate(self, other, **hints):
return Integer(2)*I*XGate(self.targets[0])
def _eval_anticommutator_YGate(self, other, **hints):
return Integer(2)*IdentityGate(self.targets[0])
def _eval_anticommutator_ZGate(self, other, **hints):
return _S.Zero
class ZGate(HermitianOperator, OneQubitGate):
"""The single qubit Z gate.
Parameters
----------
target : int
The target qubit this gate will apply to.
Examples
========
"""
gate_name = 'Z'
gate_name_latex = 'Z'
def get_target_matrix(self, format='sympy'):
return matrix_cache.get_matrix('Z', format)
def _eval_commutator_XGate(self, other, **hints):
return Integer(2)*I*YGate(self.targets[0])
def _eval_anticommutator_YGate(self, other, **hints):
return _S.Zero
class PhaseGate(OneQubitGate):
"""The single qubit phase, or S, gate.
This gate rotates the phase of the state by pi/2 if the state is ``|1>`` and
does nothing if the state is ``|0>``.
Parameters
----------
target : int
The target qubit this gate will apply to.
Examples
========
"""
is_hermitian = False
gate_name = 'S'
gate_name_latex = 'S'
def get_target_matrix(self, format='sympy'):
return matrix_cache.get_matrix('S', format)
def _eval_commutator_ZGate(self, other, **hints):
return _S.Zero
def _eval_commutator_TGate(self, other, **hints):
return _S.Zero
class TGate(OneQubitGate):
"""The single qubit pi/8 gate.
This gate rotates the phase of the state by pi/4 if the state is ``|1>`` and
does nothing if the state is ``|0>``.
Parameters
----------
target : int
The target qubit this gate will apply to.
Examples
========
"""
is_hermitian = False
gate_name = 'T'
gate_name_latex = 'T'
def get_target_matrix(self, format='sympy'):
return matrix_cache.get_matrix('T', format)
def _eval_commutator_ZGate(self, other, **hints):
return _S.Zero
def _eval_commutator_PhaseGate(self, other, **hints):
return _S.Zero
# Aliases for gate names.
H = HadamardGate
X = XGate
Y = YGate
Z = ZGate
T = TGate
Phase = S = PhaseGate
#-----------------------------------------------------------------------------
# 2 Qubit Gates
#-----------------------------------------------------------------------------
class CNotGate(HermitianOperator, CGate, TwoQubitGate):
"""Two qubit controlled-NOT.
This gate performs the NOT or X gate on the target qubit if the control
qubits all have the value 1.
Parameters
----------
label : tuple
A tuple of the form (control, target).
Examples
========
>>> from sympy.physics.quantum.gate import CNOT
>>> from sympy.physics.quantum.qapply import qapply
>>> from sympy.physics.quantum.qubit import Qubit
>>> c = CNOT(1,0)
>>> qapply(c*Qubit('10')) # note that qubits are indexed from right to left
|11>
"""
gate_name = 'CNOT'
gate_name_latex = r'\text{CNOT}'
simplify_cgate = True
#-------------------------------------------------------------------------
# Initialization
#-------------------------------------------------------------------------
@classmethod
def _eval_args(cls, args):
args = Gate._eval_args(args)
return args
@classmethod
def _eval_hilbert_space(cls, args):
"""This returns the smallest possible Hilbert space."""
return ComplexSpace(2)**(_max(args) + 1)
#-------------------------------------------------------------------------
# Properties
#-------------------------------------------------------------------------
@property
def min_qubits(self):
"""The minimum number of qubits this gate needs to act on."""
return _max(self.label) + 1
@property
def targets(self):
"""A tuple of target qubits."""
return (self.label[1],)
@property
def controls(self):
"""A tuple of control qubits."""
return (self.label[0],)
@property
def gate(self):
"""The non-controlled gate that will be applied to the targets."""
return XGate(self.label[1])
#-------------------------------------------------------------------------
# Properties
#-------------------------------------------------------------------------
# The default printing of Gate works better than those of CGate, so we
# go around the overridden methods in CGate.
def _print_label(self, printer, *args):
return Gate._print_label(self, printer, *args)
def _pretty(self, printer, *args):
return Gate._pretty(self, printer, *args)
def _latex(self, printer, *args):
return Gate._latex(self, printer, *args)
#-------------------------------------------------------------------------
# Commutator/AntiCommutator
#-------------------------------------------------------------------------
def _eval_commutator_ZGate(self, other, **hints):
"""[CNOT(i, j), Z(i)] == 0."""
if self.controls[0] == other.targets[0]:
return _S.Zero
else:
raise NotImplementedError('Commutator not implemented: %r' % other)
def _eval_commutator_TGate(self, other, **hints):
"""[CNOT(i, j), T(i)] == 0."""
return self._eval_commutator_ZGate(other, **hints)
def _eval_commutator_PhaseGate(self, other, **hints):
"""[CNOT(i, j), S(i)] == 0."""
return self._eval_commutator_ZGate(other, **hints)
def _eval_commutator_XGate(self, other, **hints):
"""[CNOT(i, j), X(j)] == 0."""
if self.targets[0] == other.targets[0]:
return _S.Zero
else:
raise NotImplementedError('Commutator not implemented: %r' % other)
def _eval_commutator_CNotGate(self, other, **hints):
"""[CNOT(i, j), CNOT(i,k)] == 0."""
if self.controls[0] == other.controls[0]:
return _S.Zero
else:
raise NotImplementedError('Commutator not implemented: %r' % other)
class SwapGate(TwoQubitGate):
"""Two qubit SWAP gate.
This gate swap the values of the two qubits.
Parameters
----------
label : tuple
A tuple of the form (target1, target2).
Examples
========
"""
is_hermitian = True
gate_name = 'SWAP'
gate_name_latex = r'\text{SWAP}'
def get_target_matrix(self, format='sympy'):
return matrix_cache.get_matrix('SWAP', format)
def decompose(self, **options):
"""Decompose the SWAP gate into CNOT gates."""
i, j = self.targets[0], self.targets[1]
g1 = CNotGate(i, j)
g2 = CNotGate(j, i)
return g1*g2*g1
def plot_gate(self, circ_plot, gate_idx):
min_wire = int(_min(self.targets))
max_wire = int(_max(self.targets))
circ_plot.control_line(gate_idx, min_wire, max_wire)
circ_plot.swap_point(gate_idx, min_wire)
circ_plot.swap_point(gate_idx, max_wire)
def _represent_ZGate(self, basis, **options):
"""Represent the SWAP gate in the computational basis.
The following representation is used to compute this:
SWAP = |1><1|x|1><1| + |0><0|x|0><0| + |1><0|x|0><1| + |0><1|x|1><0|
"""
format = options.get('format', 'sympy')
targets = [int(t) for t in self.targets]
min_target = _min(targets)
max_target = _max(targets)
nqubits = options.get('nqubits', self.min_qubits)
op01 = matrix_cache.get_matrix('op01', format)
op10 = matrix_cache.get_matrix('op10', format)
op11 = matrix_cache.get_matrix('op11', format)
op00 = matrix_cache.get_matrix('op00', format)
eye2 = matrix_cache.get_matrix('eye2', format)
result = None
for i, j in ((op01, op10), (op10, op01), (op00, op00), (op11, op11)):
product = nqubits*[eye2]
product[nqubits - min_target - 1] = i
product[nqubits - max_target - 1] = j
new_result = matrix_tensor_product(*product)
if result is None:
result = new_result
else:
result = result + new_result
return result
# Aliases for gate names.
CNOT = CNotGate
SWAP = SwapGate
def CPHASE(a,b): return CGateS((a,),Z(b))
#-----------------------------------------------------------------------------
# Represent
#-----------------------------------------------------------------------------
def represent_zbasis(controls, targets, target_matrix, nqubits, format='sympy'):
"""Represent a gate with controls, targets and target_matrix.
This function does the low-level work of representing gates as matrices
in the standard computational basis (ZGate). Currently, we support two
main cases:
1. One target qubit and no control qubits.
2. One target qubits and multiple control qubits.
For the base of multiple controls, we use the following expression [1]:
1_{2**n} + (|1><1|)^{(n-1)} x (target-matrix - 1_{2})
Parameters
----------
controls : list, tuple
A sequence of control qubits.
targets : list, tuple
A sequence of target qubits.
target_matrix : sympy.Matrix, numpy.matrix, scipy.sparse
The matrix form of the transformation to be performed on the target
qubits. The format of this matrix must match that passed into
the `format` argument.
nqubits : int
The total number of qubits used for the representation.
format : str
The format of the final matrix ('sympy', 'numpy', 'scipy.sparse').
Examples
========
References
----------
[1] http://www.johnlapeyre.com/qinf/qinf_html/node6.html.
"""
controls = [int(x) for x in controls]
targets = [int(x) for x in targets]
nqubits = int(nqubits)
# This checks for the format as well.
op11 = matrix_cache.get_matrix('op11', format)
eye2 = matrix_cache.get_matrix('eye2', format)
# Plain single qubit case
if len(controls) == 0 and len(targets) == 1:
product = []
bit = targets[0]
# Fill product with [I1,Gate,I2] such that the unitaries,
# I, cause the gate to be applied to the correct Qubit
if bit != nqubits - 1:
product.append(matrix_eye(2**(nqubits - bit - 1), format=format))
product.append(target_matrix)
if bit != 0:
product.append(matrix_eye(2**bit, format=format))
return matrix_tensor_product(*product)
# Single target, multiple controls.
elif len(targets) == 1 and len(controls) >= 1:
target = targets[0]
# Build the non-trivial part.
product2 = []
for i in range(nqubits):
product2.append(matrix_eye(2, format=format))
for control in controls:
product2[nqubits - 1 - control] = op11
product2[nqubits - 1 - target] = target_matrix - eye2
return matrix_eye(2**nqubits, format=format) + \
matrix_tensor_product(*product2)
# Multi-target, multi-control is not yet implemented.
else:
raise NotImplementedError(
'The representation of multi-target, multi-control gates '
'is not implemented.'
)
#-----------------------------------------------------------------------------
# Gate manipulation functions.
#-----------------------------------------------------------------------------
def gate_simp(circuit):
"""Simplifies gates symbolically
It first sorts gates using gate_sort. It then applies basic
simplification rules to the circuit, e.g., XGate**2 = Identity
"""
# Bubble sort out gates that commute.
circuit = gate_sort(circuit)
# Do simplifications by subing a simplification into the first element
# which can be simplified. We recursively call gate_simp with new circuit
# as input more simplifications exist.
if isinstance(circuit, Add):
return sum(gate_simp(t) for t in circuit.args)
elif isinstance(circuit, Mul):
circuit_args = circuit.args
elif isinstance(circuit, Pow):
b, e = circuit.as_base_exp()
circuit_args = (gate_simp(b)**e,)
else:
return circuit
# Iterate through each element in circuit, simplify if possible.
for i in range(len(circuit_args)):
# H,X,Y or Z squared is 1.
# T**2 = S, S**2 = Z
if isinstance(circuit_args[i], Pow):
if isinstance(circuit_args[i].base,
(HadamardGate, XGate, YGate, ZGate)) \
and isinstance(circuit_args[i].exp, Number):
# Build a new circuit taking replacing the
# H,X,Y,Z squared with one.
newargs = (circuit_args[:i] +
(circuit_args[i].base**(circuit_args[i].exp % 2),) +
circuit_args[i + 1:])
# Recursively simplify the new circuit.
circuit = gate_simp(Mul(*newargs))
break
elif isinstance(circuit_args[i].base, PhaseGate):
# Build a new circuit taking old circuit but splicing
# in simplification.
newargs = circuit_args[:i]
# Replace PhaseGate**2 with ZGate.
newargs = newargs + (ZGate(circuit_args[i].base.args[0])**
(Integer(circuit_args[i].exp/2)), circuit_args[i].base**
(circuit_args[i].exp % 2))
# Append the last elements.
newargs = newargs + circuit_args[i + 1:]
# Recursively simplify the new circuit.
circuit = gate_simp(Mul(*newargs))
break
elif isinstance(circuit_args[i].base, TGate):
# Build a new circuit taking all the old elements.
newargs = circuit_args[:i]
# Put an Phasegate in place of any TGate**2.
newargs = newargs + (PhaseGate(circuit_args[i].base.args[0])**
Integer(circuit_args[i].exp/2), circuit_args[i].base**
(circuit_args[i].exp % 2))
# Append the last elements.
newargs = newargs + circuit_args[i + 1:]
# Recursively simplify the new circuit.
circuit = gate_simp(Mul(*newargs))
break
return circuit
def gate_sort(circuit):
"""Sorts the gates while keeping track of commutation relations
This function uses a bubble sort to rearrange the order of gate
application. Keeps track of Quantum computations special commutation
relations (e.g. things that apply to the same Qubit do not commute with
each other)
circuit is the Mul of gates that are to be sorted.
"""
# Make sure we have an Add or Mul.
if isinstance(circuit, Add):
return sum(gate_sort(t) for t in circuit.args)
if isinstance(circuit, Pow):
return gate_sort(circuit.base)**circuit.exp
elif isinstance(circuit, Gate):
return circuit
if not isinstance(circuit, Mul):
return circuit
changes = True
while changes:
changes = False
circ_array = circuit.args
for i in range(len(circ_array) - 1):
# Go through each element and switch ones that are in wrong order
if isinstance(circ_array[i], (Gate, Pow)) and \
isinstance(circ_array[i + 1], (Gate, Pow)):
# If we have a Pow object, look at only the base
first_base, first_exp = circ_array[i].as_base_exp()
second_base, second_exp = circ_array[i + 1].as_base_exp()
# Use SymPy's hash based sorting. This is not mathematical
# sorting, but is rather based on comparing hashes of objects.
# See Basic.compare for details.
if first_base.compare(second_base) > 0:
if Commutator(first_base, second_base).doit() == 0:
new_args = (circuit.args[:i] + (circuit.args[i + 1],) +
(circuit.args[i],) + circuit.args[i + 2:])
circuit = Mul(*new_args)
changes = True
break
if AntiCommutator(first_base, second_base).doit() == 0:
new_args = (circuit.args[:i] + (circuit.args[i + 1],) +
(circuit.args[i],) + circuit.args[i + 2:])
sign = _S.NegativeOne**(first_exp*second_exp)
circuit = sign*Mul(*new_args)
changes = True
break
return circuit
#-----------------------------------------------------------------------------
# Utility functions
#-----------------------------------------------------------------------------
def random_circuit(ngates, nqubits, gate_space=(X, Y, Z, S, T, H, CNOT, SWAP)):
"""Return a random circuit of ngates and nqubits.
This uses an equally weighted sample of (X, Y, Z, S, T, H, CNOT, SWAP)
gates.
Parameters
----------
ngates : int
The number of gates in the circuit.
nqubits : int
The number of qubits in the circuit.
gate_space : tuple
A tuple of the gate classes that will be used in the circuit.
Repeating gate classes multiple times in this tuple will increase
the frequency they appear in the random circuit.
"""
qubit_space = range(nqubits)
result = []
for i in range(ngates):
g = random.choice(gate_space)
if g == CNotGate or g == SwapGate:
qubits = random.sample(qubit_space, 2)
g = g(*qubits)
else:
qubit = random.choice(qubit_space)
g = g(qubit)
result.append(g)
return Mul(*result)
def zx_basis_transform(self, format='sympy'):
"""Transformation matrix from Z to X basis."""
return matrix_cache.get_matrix('ZX', format)
def zy_basis_transform(self, format='sympy'):
"""Transformation matrix from Z to Y basis."""
return matrix_cache.get_matrix('ZY', format)
PK ]ZZZ���( �( sympy/physics/quantum/grover.py"""Grover's algorithm and helper functions.
Todo:
* W gate construction (or perhaps -W gate based on Mermin's book)
* Generalize the algorithm for an unknown function that returns 1 on multiple
qubit states, not just one.
* Implement _represent_ZGate in OracleGate
"""
from sympy.core.numbers import pi
from sympy.core.sympify import sympify
from sympy.core.basic import Atom
from sympy.functions.elementary.integers import floor
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.matrices.dense import eye
from sympy.core.numbers import NegativeOne
from sympy.physics.quantum.qapply import qapply
from sympy.physics.quantum.qexpr import QuantumError
from sympy.physics.quantum.hilbert import ComplexSpace
from sympy.physics.quantum.operator import UnitaryOperator
from sympy.physics.quantum.gate import Gate
from sympy.physics.quantum.qubit import IntQubit
__all__ = [
'OracleGate',
'WGate',
'superposition_basis',
'grover_iteration',
'apply_grover'
]
def superposition_basis(nqubits):
"""Creates an equal superposition of the computational basis.
Parameters
==========
nqubits : int
The number of qubits.
Returns
=======
state : Qubit
An equal superposition of the computational basis with nqubits.
Examples
========
Create an equal superposition of 2 qubits::
>>> from sympy.physics.quantum.grover import superposition_basis
>>> superposition_basis(2)
|0>/2 + |1>/2 + |2>/2 + |3>/2
"""
amp = 1/sqrt(2**nqubits)
return sum(amp*IntQubit(n, nqubits=nqubits) for n in range(2**nqubits))
class OracleGateFunction(Atom):
"""Wrapper for python functions used in `OracleGate`s"""
def __new__(cls, function):
if not callable(function):
raise TypeError('Callable expected, got: %r' % function)
obj = Atom.__new__(cls)
obj.function = function
return obj
def _hashable_content(self):
return type(self), self.function
def __call__(self, *args):
return self.function(*args)
class OracleGate(Gate):
"""A black box gate.
The gate marks the desired qubits of an unknown function by flipping
the sign of the qubits. The unknown function returns true when it
finds its desired qubits and false otherwise.
Parameters
==========
qubits : int
Number of qubits.
oracle : callable
A callable function that returns a boolean on a computational basis.
Examples
========
Apply an Oracle gate that flips the sign of ``|2>`` on different qubits::
>>> from sympy.physics.quantum.qubit import IntQubit
>>> from sympy.physics.quantum.qapply import qapply
>>> from sympy.physics.quantum.grover import OracleGate
>>> f = lambda qubits: qubits == IntQubit(2)
>>> v = OracleGate(2, f)
>>> qapply(v*IntQubit(2))
-|2>
>>> qapply(v*IntQubit(3))
|3>
"""
gate_name = 'V'
gate_name_latex = 'V'
#-------------------------------------------------------------------------
# Initialization/creation
#-------------------------------------------------------------------------
@classmethod
def _eval_args(cls, args):
if len(args) != 2:
raise QuantumError(
'Insufficient/excessive arguments to Oracle. Please ' +
'supply the number of qubits and an unknown function.'
)
sub_args = (args[0],)
sub_args = UnitaryOperator._eval_args(sub_args)
if not sub_args[0].is_Integer:
raise TypeError('Integer expected, got: %r' % sub_args[0])
function = args[1]
if not isinstance(function, OracleGateFunction):
function = OracleGateFunction(function)
return (sub_args[0], function)
@classmethod
def _eval_hilbert_space(cls, args):
"""This returns the smallest possible Hilbert space."""
return ComplexSpace(2)**args[0]
#-------------------------------------------------------------------------
# Properties
#-------------------------------------------------------------------------
@property
def search_function(self):
"""The unknown function that helps find the sought after qubits."""
return self.label[1]
@property
def targets(self):
"""A tuple of target qubits."""
return sympify(tuple(range(self.args[0])))
#-------------------------------------------------------------------------
# Apply
#-------------------------------------------------------------------------
def _apply_operator_Qubit(self, qubits, **options):
"""Apply this operator to a Qubit subclass.
Parameters
==========
qubits : Qubit
The qubit subclass to apply this operator to.
Returns
=======
state : Expr
The resulting quantum state.
"""
if qubits.nqubits != self.nqubits:
raise QuantumError(
'OracleGate operates on %r qubits, got: %r'
% (self.nqubits, qubits.nqubits)
)
# If function returns 1 on qubits
# return the negative of the qubits (flip the sign)
if self.search_function(qubits):
return -qubits
else:
return qubits
#-------------------------------------------------------------------------
# Represent
#-------------------------------------------------------------------------
def _represent_ZGate(self, basis, **options):
"""
Represent the OracleGate in the computational basis.
"""
nbasis = 2**self.nqubits # compute it only once
matrixOracle = eye(nbasis)
# Flip the sign given the output of the oracle function
for i in range(nbasis):
if self.search_function(IntQubit(i, nqubits=self.nqubits)):
matrixOracle[i, i] = NegativeOne()
return matrixOracle
class WGate(Gate):
"""General n qubit W Gate in Grover's algorithm.
The gate performs the operation ``2|phi><phi| - 1`` on some qubits.
``|phi> = (tensor product of n Hadamards)*(|0> with n qubits)``
Parameters
==========
nqubits : int
The number of qubits to operate on
"""
gate_name = 'W'
gate_name_latex = 'W'
@classmethod
def _eval_args(cls, args):
if len(args) != 1:
raise QuantumError(
'Insufficient/excessive arguments to W gate. Please ' +
'supply the number of qubits to operate on.'
)
args = UnitaryOperator._eval_args(args)
if not args[0].is_Integer:
raise TypeError('Integer expected, got: %r' % args[0])
return args
#-------------------------------------------------------------------------
# Properties
#-------------------------------------------------------------------------
@property
def targets(self):
return sympify(tuple(reversed(range(self.args[0]))))
#-------------------------------------------------------------------------
# Apply
#-------------------------------------------------------------------------
def _apply_operator_Qubit(self, qubits, **options):
"""
qubits: a set of qubits (Qubit)
Returns: quantum object (quantum expression - QExpr)
"""
if qubits.nqubits != self.nqubits:
raise QuantumError(
'WGate operates on %r qubits, got: %r'
% (self.nqubits, qubits.nqubits)
)
# See 'Quantum Computer Science' by David Mermin p.92 -> W|a> result
# Return (2/(sqrt(2^n)))|phi> - |a> where |a> is the current basis
# state and phi is the superposition of basis states (see function
# create_computational_basis above)
basis_states = superposition_basis(self.nqubits)
change_to_basis = (2/sqrt(2**self.nqubits))*basis_states
return change_to_basis - qubits
def grover_iteration(qstate, oracle):
"""Applies one application of the Oracle and W Gate, WV.
Parameters
==========
qstate : Qubit
A superposition of qubits.
oracle : OracleGate
The black box operator that flips the sign of the desired basis qubits.
Returns
=======
Qubit : The qubits after applying the Oracle and W gate.
Examples
========
Perform one iteration of grover's algorithm to see a phase change::
>>> from sympy.physics.quantum.qapply import qapply
>>> from sympy.physics.quantum.qubit import IntQubit
>>> from sympy.physics.quantum.grover import OracleGate
>>> from sympy.physics.quantum.grover import superposition_basis
>>> from sympy.physics.quantum.grover import grover_iteration
>>> numqubits = 2
>>> basis_states = superposition_basis(numqubits)
>>> f = lambda qubits: qubits == IntQubit(2)
>>> v = OracleGate(numqubits, f)
>>> qapply(grover_iteration(basis_states, v))
|2>
"""
wgate = WGate(oracle.nqubits)
return wgate*oracle*qstate
def apply_grover(oracle, nqubits, iterations=None):
"""Applies grover's algorithm.
Parameters
==========
oracle : callable
The unknown callable function that returns true when applied to the
desired qubits and false otherwise.
Returns
=======
state : Expr
The resulting state after Grover's algorithm has been iterated.
Examples
========
Apply grover's algorithm to an even superposition of 2 qubits::
>>> from sympy.physics.quantum.qapply import qapply
>>> from sympy.physics.quantum.qubit import IntQubit
>>> from sympy.physics.quantum.grover import apply_grover
>>> f = lambda qubits: qubits == IntQubit(2)
>>> qapply(apply_grover(f, 2))
|2>
"""
if nqubits <= 0:
raise QuantumError(
'Grover\'s algorithm needs nqubits > 0, received %r qubits'
% nqubits
)
if iterations is None:
iterations = floor(sqrt(2**nqubits)*(pi/4))
v = OracleGate(nqubits, oracle)
iterated = superposition_basis(nqubits)
for iter in range(iterations):
iterated = grover_iteration(iterated, v)
iterated = qapply(iterated)
return iterated
PK ]ZZZ� ��L �L sympy/physics/quantum/hilbert.py"""Hilbert spaces for quantum mechanics.
Authors:
* Brian Granger
* Matt Curry
"""
from functools import reduce
from sympy.core.basic import Basic
from sympy.core.singleton import S
from sympy.core.sympify import sympify
from sympy.sets.sets import Interval
from sympy.printing.pretty.stringpict import prettyForm
from sympy.physics.quantum.qexpr import QuantumError
__all__ = [
'HilbertSpaceError',
'HilbertSpace',
'TensorProductHilbertSpace',
'TensorPowerHilbertSpace',
'DirectSumHilbertSpace',
'ComplexSpace',
'L2',
'FockSpace'
]
#-----------------------------------------------------------------------------
# Main objects
#-----------------------------------------------------------------------------
class HilbertSpaceError(QuantumError):
pass
#-----------------------------------------------------------------------------
# Main objects
#-----------------------------------------------------------------------------
class HilbertSpace(Basic):
"""An abstract Hilbert space for quantum mechanics.
In short, a Hilbert space is an abstract vector space that is complete
with inner products defined [1]_.
Examples
========
>>> from sympy.physics.quantum.hilbert import HilbertSpace
>>> hs = HilbertSpace()
>>> hs
H
References
==========
.. [1] https://en.wikipedia.org/wiki/Hilbert_space
"""
def __new__(cls):
obj = Basic.__new__(cls)
return obj
@property
def dimension(self):
"""Return the Hilbert dimension of the space."""
raise NotImplementedError('This Hilbert space has no dimension.')
def __add__(self, other):
return DirectSumHilbertSpace(self, other)
def __radd__(self, other):
return DirectSumHilbertSpace(other, self)
def __mul__(self, other):
return TensorProductHilbertSpace(self, other)
def __rmul__(self, other):
return TensorProductHilbertSpace(other, self)
def __pow__(self, other, mod=None):
if mod is not None:
raise ValueError('The third argument to __pow__ is not supported \
for Hilbert spaces.')
return TensorPowerHilbertSpace(self, other)
def __contains__(self, other):
"""Is the operator or state in this Hilbert space.
This is checked by comparing the classes of the Hilbert spaces, not
the instances. This is to allow Hilbert Spaces with symbolic
dimensions.
"""
if other.hilbert_space.__class__ == self.__class__:
return True
else:
return False
def _sympystr(self, printer, *args):
return 'H'
def _pretty(self, printer, *args):
ustr = '\N{LATIN CAPITAL LETTER H}'
return prettyForm(ustr)
def _latex(self, printer, *args):
return r'\mathcal{H}'
class ComplexSpace(HilbertSpace):
"""Finite dimensional Hilbert space of complex vectors.
The elements of this Hilbert space are n-dimensional complex valued
vectors with the usual inner product that takes the complex conjugate
of the vector on the right.
A classic example of this type of Hilbert space is spin-1/2, which is
``ComplexSpace(2)``. Generalizing to spin-s, the space is
``ComplexSpace(2*s+1)``. Quantum computing with N qubits is done with the
direct product space ``ComplexSpace(2)**N``.
Examples
========
>>> from sympy import symbols
>>> from sympy.physics.quantum.hilbert import ComplexSpace
>>> c1 = ComplexSpace(2)
>>> c1
C(2)
>>> c1.dimension
2
>>> n = symbols('n')
>>> c2 = ComplexSpace(n)
>>> c2
C(n)
>>> c2.dimension
n
"""
def __new__(cls, dimension):
dimension = sympify(dimension)
r = cls.eval(dimension)
if isinstance(r, Basic):
return r
obj = Basic.__new__(cls, dimension)
return obj
@classmethod
def eval(cls, dimension):
if len(dimension.atoms()) == 1:
if not (dimension.is_Integer and dimension > 0 or dimension is S.Infinity
or dimension.is_Symbol):
raise TypeError('The dimension of a ComplexSpace can only'
'be a positive integer, oo, or a Symbol: %r'
% dimension)
else:
for dim in dimension.atoms():
if not (dim.is_Integer or dim is S.Infinity or dim.is_Symbol):
raise TypeError('The dimension of a ComplexSpace can only'
' contain integers, oo, or a Symbol: %r'
% dim)
@property
def dimension(self):
return self.args[0]
def _sympyrepr(self, printer, *args):
return "%s(%s)" % (self.__class__.__name__,
printer._print(self.dimension, *args))
def _sympystr(self, printer, *args):
return "C(%s)" % printer._print(self.dimension, *args)
def _pretty(self, printer, *args):
ustr = '\N{LATIN CAPITAL LETTER C}'
pform_exp = printer._print(self.dimension, *args)
pform_base = prettyForm(ustr)
return pform_base**pform_exp
def _latex(self, printer, *args):
return r'\mathcal{C}^{%s}' % printer._print(self.dimension, *args)
class L2(HilbertSpace):
"""The Hilbert space of square integrable functions on an interval.
An L2 object takes in a single SymPy Interval argument which represents
the interval its functions (vectors) are defined on.
Examples
========
>>> from sympy import Interval, oo
>>> from sympy.physics.quantum.hilbert import L2
>>> hs = L2(Interval(0,oo))
>>> hs
L2(Interval(0, oo))
>>> hs.dimension
oo
>>> hs.interval
Interval(0, oo)
"""
def __new__(cls, interval):
if not isinstance(interval, Interval):
raise TypeError('L2 interval must be an Interval instance: %r'
% interval)
obj = Basic.__new__(cls, interval)
return obj
@property
def dimension(self):
return S.Infinity
@property
def interval(self):
return self.args[0]
def _sympyrepr(self, printer, *args):
return "L2(%s)" % printer._print(self.interval, *args)
def _sympystr(self, printer, *args):
return "L2(%s)" % printer._print(self.interval, *args)
def _pretty(self, printer, *args):
pform_exp = prettyForm('2')
pform_base = prettyForm('L')
return pform_base**pform_exp
def _latex(self, printer, *args):
interval = printer._print(self.interval, *args)
return r'{\mathcal{L}^2}\left( %s \right)' % interval
class FockSpace(HilbertSpace):
"""The Hilbert space for second quantization.
Technically, this Hilbert space is a infinite direct sum of direct
products of single particle Hilbert spaces [1]_. This is a mess, so we have
a class to represent it directly.
Examples
========
>>> from sympy.physics.quantum.hilbert import FockSpace
>>> hs = FockSpace()
>>> hs
F
>>> hs.dimension
oo
References
==========
.. [1] https://en.wikipedia.org/wiki/Fock_space
"""
def __new__(cls):
obj = Basic.__new__(cls)
return obj
@property
def dimension(self):
return S.Infinity
def _sympyrepr(self, printer, *args):
return "FockSpace()"
def _sympystr(self, printer, *args):
return "F"
def _pretty(self, printer, *args):
ustr = '\N{LATIN CAPITAL LETTER F}'
return prettyForm(ustr)
def _latex(self, printer, *args):
return r'\mathcal{F}'
class TensorProductHilbertSpace(HilbertSpace):
"""A tensor product of Hilbert spaces [1]_.
The tensor product between Hilbert spaces is represented by the
operator ``*`` Products of the same Hilbert space will be combined into
tensor powers.
A ``TensorProductHilbertSpace`` object takes in an arbitrary number of
``HilbertSpace`` objects as its arguments. In addition, multiplication of
``HilbertSpace`` objects will automatically return this tensor product
object.
Examples
========
>>> from sympy.physics.quantum.hilbert import ComplexSpace, FockSpace
>>> from sympy import symbols
>>> c = ComplexSpace(2)
>>> f = FockSpace()
>>> hs = c*f
>>> hs
C(2)*F
>>> hs.dimension
oo
>>> hs.spaces
(C(2), F)
>>> c1 = ComplexSpace(2)
>>> n = symbols('n')
>>> c2 = ComplexSpace(n)
>>> hs = c1*c2
>>> hs
C(2)*C(n)
>>> hs.dimension
2*n
References
==========
.. [1] https://en.wikipedia.org/wiki/Hilbert_space#Tensor_products
"""
def __new__(cls, *args):
r = cls.eval(args)
if isinstance(r, Basic):
return r
obj = Basic.__new__(cls, *args)
return obj
@classmethod
def eval(cls, args):
"""Evaluates the direct product."""
new_args = []
recall = False
#flatten arguments
for arg in args:
if isinstance(arg, TensorProductHilbertSpace):
new_args.extend(arg.args)
recall = True
elif isinstance(arg, (HilbertSpace, TensorPowerHilbertSpace)):
new_args.append(arg)
else:
raise TypeError('Hilbert spaces can only be multiplied by \
other Hilbert spaces: %r' % arg)
#combine like arguments into direct powers
comb_args = []
prev_arg = None
for new_arg in new_args:
if prev_arg is not None:
if isinstance(new_arg, TensorPowerHilbertSpace) and \
isinstance(prev_arg, TensorPowerHilbertSpace) and \
new_arg.base == prev_arg.base:
prev_arg = new_arg.base**(new_arg.exp + prev_arg.exp)
elif isinstance(new_arg, TensorPowerHilbertSpace) and \
new_arg.base == prev_arg:
prev_arg = prev_arg**(new_arg.exp + 1)
elif isinstance(prev_arg, TensorPowerHilbertSpace) and \
new_arg == prev_arg.base:
prev_arg = new_arg**(prev_arg.exp + 1)
elif new_arg == prev_arg:
prev_arg = new_arg**2
else:
comb_args.append(prev_arg)
prev_arg = new_arg
elif prev_arg is None:
prev_arg = new_arg
comb_args.append(prev_arg)
if recall:
return TensorProductHilbertSpace(*comb_args)
elif len(comb_args) == 1:
return TensorPowerHilbertSpace(comb_args[0].base, comb_args[0].exp)
else:
return None
@property
def dimension(self):
arg_list = [arg.dimension for arg in self.args]
if S.Infinity in arg_list:
return S.Infinity
else:
return reduce(lambda x, y: x*y, arg_list)
@property
def spaces(self):
"""A tuple of the Hilbert spaces in this tensor product."""
return self.args
def _spaces_printer(self, printer, *args):
spaces_strs = []
for arg in self.args:
s = printer._print(arg, *args)
if isinstance(arg, DirectSumHilbertSpace):
s = '(%s)' % s
spaces_strs.append(s)
return spaces_strs
def _sympyrepr(self, printer, *args):
spaces_reprs = self._spaces_printer(printer, *args)
return "TensorProductHilbertSpace(%s)" % ','.join(spaces_reprs)
def _sympystr(self, printer, *args):
spaces_strs = self._spaces_printer(printer, *args)
return '*'.join(spaces_strs)
def _pretty(self, printer, *args):
length = len(self.args)
pform = printer._print('', *args)
for i in range(length):
next_pform = printer._print(self.args[i], *args)
if isinstance(self.args[i], (DirectSumHilbertSpace,
TensorProductHilbertSpace)):
next_pform = prettyForm(
*next_pform.parens(left='(', right=')')
)
pform = prettyForm(*pform.right(next_pform))
if i != length - 1:
if printer._use_unicode:
pform = prettyForm(*pform.right(' ' + '\N{N-ARY CIRCLED TIMES OPERATOR}' + ' '))
else:
pform = prettyForm(*pform.right(' x '))
return pform
def _latex(self, printer, *args):
length = len(self.args)
s = ''
for i in range(length):
arg_s = printer._print(self.args[i], *args)
if isinstance(self.args[i], (DirectSumHilbertSpace,
TensorProductHilbertSpace)):
arg_s = r'\left(%s\right)' % arg_s
s = s + arg_s
if i != length - 1:
s = s + r'\otimes '
return s
class DirectSumHilbertSpace(HilbertSpace):
"""A direct sum of Hilbert spaces [1]_.
This class uses the ``+`` operator to represent direct sums between
different Hilbert spaces.
A ``DirectSumHilbertSpace`` object takes in an arbitrary number of
``HilbertSpace`` objects as its arguments. Also, addition of
``HilbertSpace`` objects will automatically return a direct sum object.
Examples
========
>>> from sympy.physics.quantum.hilbert import ComplexSpace, FockSpace
>>> c = ComplexSpace(2)
>>> f = FockSpace()
>>> hs = c+f
>>> hs
C(2)+F
>>> hs.dimension
oo
>>> list(hs.spaces)
[C(2), F]
References
==========
.. [1] https://en.wikipedia.org/wiki/Hilbert_space#Direct_sums
"""
def __new__(cls, *args):
r = cls.eval(args)
if isinstance(r, Basic):
return r
obj = Basic.__new__(cls, *args)
return obj
@classmethod
def eval(cls, args):
"""Evaluates the direct product."""
new_args = []
recall = False
#flatten arguments
for arg in args:
if isinstance(arg, DirectSumHilbertSpace):
new_args.extend(arg.args)
recall = True
elif isinstance(arg, HilbertSpace):
new_args.append(arg)
else:
raise TypeError('Hilbert spaces can only be summed with other \
Hilbert spaces: %r' % arg)
if recall:
return DirectSumHilbertSpace(*new_args)
else:
return None
@property
def dimension(self):
arg_list = [arg.dimension for arg in self.args]
if S.Infinity in arg_list:
return S.Infinity
else:
return reduce(lambda x, y: x + y, arg_list)
@property
def spaces(self):
"""A tuple of the Hilbert spaces in this direct sum."""
return self.args
def _sympyrepr(self, printer, *args):
spaces_reprs = [printer._print(arg, *args) for arg in self.args]
return "DirectSumHilbertSpace(%s)" % ','.join(spaces_reprs)
def _sympystr(self, printer, *args):
spaces_strs = [printer._print(arg, *args) for arg in self.args]
return '+'.join(spaces_strs)
def _pretty(self, printer, *args):
length = len(self.args)
pform = printer._print('', *args)
for i in range(length):
next_pform = printer._print(self.args[i], *args)
if isinstance(self.args[i], (DirectSumHilbertSpace,
TensorProductHilbertSpace)):
next_pform = prettyForm(
*next_pform.parens(left='(', right=')')
)
pform = prettyForm(*pform.right(next_pform))
if i != length - 1:
if printer._use_unicode:
pform = prettyForm(*pform.right(' \N{CIRCLED PLUS} '))
else:
pform = prettyForm(*pform.right(' + '))
return pform
def _latex(self, printer, *args):
length = len(self.args)
s = ''
for i in range(length):
arg_s = printer._print(self.args[i], *args)
if isinstance(self.args[i], (DirectSumHilbertSpace,
TensorProductHilbertSpace)):
arg_s = r'\left(%s\right)' % arg_s
s = s + arg_s
if i != length - 1:
s = s + r'\oplus '
return s
class TensorPowerHilbertSpace(HilbertSpace):
"""An exponentiated Hilbert space [1]_.
Tensor powers (repeated tensor products) are represented by the
operator ``**`` Identical Hilbert spaces that are multiplied together
will be automatically combined into a single tensor power object.
Any Hilbert space, product, or sum may be raised to a tensor power. The
``TensorPowerHilbertSpace`` takes two arguments: the Hilbert space; and the
tensor power (number).
Examples
========
>>> from sympy.physics.quantum.hilbert import ComplexSpace, FockSpace
>>> from sympy import symbols
>>> n = symbols('n')
>>> c = ComplexSpace(2)
>>> hs = c**n
>>> hs
C(2)**n
>>> hs.dimension
2**n
>>> c = ComplexSpace(2)
>>> c*c
C(2)**2
>>> f = FockSpace()
>>> c*f*f
C(2)*F**2
References
==========
.. [1] https://en.wikipedia.org/wiki/Hilbert_space#Tensor_products
"""
def __new__(cls, *args):
r = cls.eval(args)
if isinstance(r, Basic):
return r
return Basic.__new__(cls, *r)
@classmethod
def eval(cls, args):
new_args = args[0], sympify(args[1])
exp = new_args[1]
#simplify hs**1 -> hs
if exp is S.One:
return args[0]
#simplify hs**0 -> 1
if exp is S.Zero:
return S.One
#check (and allow) for hs**(x+42+y...) case
if len(exp.atoms()) == 1:
if not (exp.is_Integer and exp >= 0 or exp.is_Symbol):
raise ValueError('Hilbert spaces can only be raised to \
positive integers or Symbols: %r' % exp)
else:
for power in exp.atoms():
if not (power.is_Integer or power.is_Symbol):
raise ValueError('Tensor powers can only contain integers \
or Symbols: %r' % power)
return new_args
@property
def base(self):
return self.args[0]
@property
def exp(self):
return self.args[1]
@property
def dimension(self):
if self.base.dimension is S.Infinity:
return S.Infinity
else:
return self.base.dimension**self.exp
def _sympyrepr(self, printer, *args):
return "TensorPowerHilbertSpace(%s,%s)" % (printer._print(self.base,
*args), printer._print(self.exp, *args))
def _sympystr(self, printer, *args):
return "%s**%s" % (printer._print(self.base, *args),
printer._print(self.exp, *args))
def _pretty(self, printer, *args):
pform_exp = printer._print(self.exp, *args)
if printer._use_unicode:
pform_exp = prettyForm(*pform_exp.left(prettyForm('\N{N-ARY CIRCLED TIMES OPERATOR}')))
else:
pform_exp = prettyForm(*pform_exp.left(prettyForm('x')))
pform_base = printer._print(self.base, *args)
return pform_base**pform_exp
def _latex(self, printer, *args):
base = printer._print(self.base, *args)
exp = printer._print(self.exp, *args)
return r'{%s}^{\otimes %s}' % (base, exp)
PK ]ZZZ: �k�k �k ' sympy/physics/quantum/identitysearch.pyfrom collections import deque
from sympy.core.random import randint
from sympy.external import import_module
from sympy.core.basic import Basic
from sympy.core.mul import Mul
from sympy.core.numbers import Number, equal_valued
from sympy.core.power import Pow
from sympy.core.singleton import S
from sympy.physics.quantum.represent import represent
from sympy.physics.quantum.dagger import Dagger
__all__ = [
# Public interfaces
'generate_gate_rules',
'generate_equivalent_ids',
'GateIdentity',
'bfs_identity_search',
'random_identity_search',
# "Private" functions
'is_scalar_sparse_matrix',
'is_scalar_nonsparse_matrix',
'is_degenerate',
'is_reducible',
]
np = import_module('numpy')
scipy = import_module('scipy', import_kwargs={'fromlist': ['sparse']})
def is_scalar_sparse_matrix(circuit, nqubits, identity_only, eps=1e-11):
"""Checks if a given scipy.sparse matrix is a scalar matrix.
A scalar matrix is such that B = bI, where B is the scalar
matrix, b is some scalar multiple, and I is the identity
matrix. A scalar matrix would have only the element b along
it's main diagonal and zeroes elsewhere.
Parameters
==========
circuit : Gate tuple
Sequence of quantum gates representing a quantum circuit
nqubits : int
Number of qubits in the circuit
identity_only : bool
Check for only identity matrices
eps : number
The tolerance value for zeroing out elements in the matrix.
Values in the range [-eps, +eps] will be changed to a zero.
"""
if not np or not scipy:
pass
matrix = represent(Mul(*circuit), nqubits=nqubits,
format='scipy.sparse')
# In some cases, represent returns a 1D scalar value in place
# of a multi-dimensional scalar matrix
if (isinstance(matrix, int)):
return matrix == 1 if identity_only else True
# If represent returns a matrix, check if the matrix is diagonal
# and if every item along the diagonal is the same
else:
# Due to floating pointing operations, must zero out
# elements that are "very" small in the dense matrix
# See parameter for default value.
# Get the ndarray version of the dense matrix
dense_matrix = matrix.todense().getA()
# Since complex values can't be compared, must split
# the matrix into real and imaginary components
# Find the real values in between -eps and eps
bool_real = np.logical_and(dense_matrix.real > -eps,
dense_matrix.real < eps)
# Find the imaginary values between -eps and eps
bool_imag = np.logical_and(dense_matrix.imag > -eps,
dense_matrix.imag < eps)
# Replaces values between -eps and eps with 0
corrected_real = np.where(bool_real, 0.0, dense_matrix.real)
corrected_imag = np.where(bool_imag, 0.0, dense_matrix.imag)
# Convert the matrix with real values into imaginary values
corrected_imag = corrected_imag * complex(1j)
# Recombine the real and imaginary components
corrected_dense = corrected_real + corrected_imag
# Check if it's diagonal
row_indices = corrected_dense.nonzero()[0]
col_indices = corrected_dense.nonzero()[1]
# Check if the rows indices and columns indices are the same
# If they match, then matrix only contains elements along diagonal
bool_indices = row_indices == col_indices
is_diagonal = bool_indices.all()
first_element = corrected_dense[0][0]
# If the first element is a zero, then can't rescale matrix
# and definitely not diagonal
if (first_element == 0.0 + 0.0j):
return False
# The dimensions of the dense matrix should still
# be 2^nqubits if there are elements all along the
# the main diagonal
trace_of_corrected = (corrected_dense/first_element).trace()
expected_trace = pow(2, nqubits)
has_correct_trace = trace_of_corrected == expected_trace
# If only looking for identity matrices
# first element must be a 1
real_is_one = abs(first_element.real - 1.0) < eps
imag_is_zero = abs(first_element.imag) < eps
is_one = real_is_one and imag_is_zero
is_identity = is_one if identity_only else True
return bool(is_diagonal and has_correct_trace and is_identity)
def is_scalar_nonsparse_matrix(circuit, nqubits, identity_only, eps=None):
"""Checks if a given circuit, in matrix form, is equivalent to
a scalar value.
Parameters
==========
circuit : Gate tuple
Sequence of quantum gates representing a quantum circuit
nqubits : int
Number of qubits in the circuit
identity_only : bool
Check for only identity matrices
eps : number
This argument is ignored. It is just for signature compatibility with
is_scalar_sparse_matrix.
Note: Used in situations when is_scalar_sparse_matrix has bugs
"""
matrix = represent(Mul(*circuit), nqubits=nqubits)
# In some cases, represent returns a 1D scalar value in place
# of a multi-dimensional scalar matrix
if (isinstance(matrix, Number)):
return matrix == 1 if identity_only else True
# If represent returns a matrix, check if the matrix is diagonal
# and if every item along the diagonal is the same
else:
# Added up the diagonal elements
matrix_trace = matrix.trace()
# Divide the trace by the first element in the matrix
# if matrix is not required to be the identity matrix
adjusted_matrix_trace = (matrix_trace/matrix[0]
if not identity_only
else matrix_trace)
is_identity = equal_valued(matrix[0], 1) if identity_only else True
has_correct_trace = adjusted_matrix_trace == pow(2, nqubits)
# The matrix is scalar if it's diagonal and the adjusted trace
# value is equal to 2^nqubits
return bool(
matrix.is_diagonal() and has_correct_trace and is_identity)
if np and scipy:
is_scalar_matrix = is_scalar_sparse_matrix
else:
is_scalar_matrix = is_scalar_nonsparse_matrix
def _get_min_qubits(a_gate):
if isinstance(a_gate, Pow):
return a_gate.base.min_qubits
else:
return a_gate.min_qubits
def ll_op(left, right):
"""Perform a LL operation.
A LL operation multiplies both left and right circuits
with the dagger of the left circuit's leftmost gate, and
the dagger is multiplied on the left side of both circuits.
If a LL is possible, it returns the new gate rule as a
2-tuple (LHS, RHS), where LHS is the left circuit and
and RHS is the right circuit of the new rule.
If a LL is not possible, None is returned.
Parameters
==========
left : Gate tuple
The left circuit of a gate rule expression.
right : Gate tuple
The right circuit of a gate rule expression.
Examples
========
Generate a new gate rule using a LL operation:
>>> from sympy.physics.quantum.identitysearch import ll_op
>>> from sympy.physics.quantum.gate import X, Y, Z
>>> x = X(0); y = Y(0); z = Z(0)
>>> ll_op((x, y, z), ())
((Y(0), Z(0)), (X(0),))
>>> ll_op((y, z), (x,))
((Z(0),), (Y(0), X(0)))
"""
if (len(left) > 0):
ll_gate = left[0]
ll_gate_is_unitary = is_scalar_matrix(
(Dagger(ll_gate), ll_gate), _get_min_qubits(ll_gate), True)
if (len(left) > 0 and ll_gate_is_unitary):
# Get the new left side w/o the leftmost gate
new_left = left[1:len(left)]
# Add the leftmost gate to the left position on the right side
new_right = (Dagger(ll_gate),) + right
# Return the new gate rule
return (new_left, new_right)
return None
def lr_op(left, right):
"""Perform a LR operation.
A LR operation multiplies both left and right circuits
with the dagger of the left circuit's rightmost gate, and
the dagger is multiplied on the right side of both circuits.
If a LR is possible, it returns the new gate rule as a
2-tuple (LHS, RHS), where LHS is the left circuit and
and RHS is the right circuit of the new rule.
If a LR is not possible, None is returned.
Parameters
==========
left : Gate tuple
The left circuit of a gate rule expression.
right : Gate tuple
The right circuit of a gate rule expression.
Examples
========
Generate a new gate rule using a LR operation:
>>> from sympy.physics.quantum.identitysearch import lr_op
>>> from sympy.physics.quantum.gate import X, Y, Z
>>> x = X(0); y = Y(0); z = Z(0)
>>> lr_op((x, y, z), ())
((X(0), Y(0)), (Z(0),))
>>> lr_op((x, y), (z,))
((X(0),), (Z(0), Y(0)))
"""
if (len(left) > 0):
lr_gate = left[len(left) - 1]
lr_gate_is_unitary = is_scalar_matrix(
(Dagger(lr_gate), lr_gate), _get_min_qubits(lr_gate), True)
if (len(left) > 0 and lr_gate_is_unitary):
# Get the new left side w/o the rightmost gate
new_left = left[0:len(left) - 1]
# Add the rightmost gate to the right position on the right side
new_right = right + (Dagger(lr_gate),)
# Return the new gate rule
return (new_left, new_right)
return None
def rl_op(left, right):
"""Perform a RL operation.
A RL operation multiplies both left and right circuits
with the dagger of the right circuit's leftmost gate, and
the dagger is multiplied on the left side of both circuits.
If a RL is possible, it returns the new gate rule as a
2-tuple (LHS, RHS), where LHS is the left circuit and
and RHS is the right circuit of the new rule.
If a RL is not possible, None is returned.
Parameters
==========
left : Gate tuple
The left circuit of a gate rule expression.
right : Gate tuple
The right circuit of a gate rule expression.
Examples
========
Generate a new gate rule using a RL operation:
>>> from sympy.physics.quantum.identitysearch import rl_op
>>> from sympy.physics.quantum.gate import X, Y, Z
>>> x = X(0); y = Y(0); z = Z(0)
>>> rl_op((x,), (y, z))
((Y(0), X(0)), (Z(0),))
>>> rl_op((x, y), (z,))
((Z(0), X(0), Y(0)), ())
"""
if (len(right) > 0):
rl_gate = right[0]
rl_gate_is_unitary = is_scalar_matrix(
(Dagger(rl_gate), rl_gate), _get_min_qubits(rl_gate), True)
if (len(right) > 0 and rl_gate_is_unitary):
# Get the new right side w/o the leftmost gate
new_right = right[1:len(right)]
# Add the leftmost gate to the left position on the left side
new_left = (Dagger(rl_gate),) + left
# Return the new gate rule
return (new_left, new_right)
return None
def rr_op(left, right):
"""Perform a RR operation.
A RR operation multiplies both left and right circuits
with the dagger of the right circuit's rightmost gate, and
the dagger is multiplied on the right side of both circuits.
If a RR is possible, it returns the new gate rule as a
2-tuple (LHS, RHS), where LHS is the left circuit and
and RHS is the right circuit of the new rule.
If a RR is not possible, None is returned.
Parameters
==========
left : Gate tuple
The left circuit of a gate rule expression.
right : Gate tuple
The right circuit of a gate rule expression.
Examples
========
Generate a new gate rule using a RR operation:
>>> from sympy.physics.quantum.identitysearch import rr_op
>>> from sympy.physics.quantum.gate import X, Y, Z
>>> x = X(0); y = Y(0); z = Z(0)
>>> rr_op((x, y), (z,))
((X(0), Y(0), Z(0)), ())
>>> rr_op((x,), (y, z))
((X(0), Z(0)), (Y(0),))
"""
if (len(right) > 0):
rr_gate = right[len(right) - 1]
rr_gate_is_unitary = is_scalar_matrix(
(Dagger(rr_gate), rr_gate), _get_min_qubits(rr_gate), True)
if (len(right) > 0 and rr_gate_is_unitary):
# Get the new right side w/o the rightmost gate
new_right = right[0:len(right) - 1]
# Add the rightmost gate to the right position on the right side
new_left = left + (Dagger(rr_gate),)
# Return the new gate rule
return (new_left, new_right)
return None
def generate_gate_rules(gate_seq, return_as_muls=False):
"""Returns a set of gate rules. Each gate rules is represented
as a 2-tuple of tuples or Muls. An empty tuple represents an arbitrary
scalar value.
This function uses the four operations (LL, LR, RL, RR)
to generate the gate rules.
A gate rule is an expression such as ABC = D or AB = CD, where
A, B, C, and D are gates. Each value on either side of the
equal sign represents a circuit. The four operations allow
one to find a set of equivalent circuits from a gate identity.
The letters denoting the operation tell the user what
activities to perform on each expression. The first letter
indicates which side of the equal sign to focus on. The
second letter indicates which gate to focus on given the
side. Once this information is determined, the inverse
of the gate is multiplied on both circuits to create a new
gate rule.
For example, given the identity, ABCD = 1, a LL operation
means look at the left value and multiply both left sides by the
inverse of the leftmost gate A. If A is Hermitian, the inverse
of A is still A. The resulting new rule is BCD = A.
The following is a summary of the four operations. Assume
that in the examples, all gates are Hermitian.
LL : left circuit, left multiply
ABCD = E -> AABCD = AE -> BCD = AE
LR : left circuit, right multiply
ABCD = E -> ABCDD = ED -> ABC = ED
RL : right circuit, left multiply
ABC = ED -> EABC = EED -> EABC = D
RR : right circuit, right multiply
AB = CD -> ABD = CDD -> ABD = C
The number of gate rules generated is n*(n+1), where n
is the number of gates in the sequence (unproven).
Parameters
==========
gate_seq : Gate tuple, Mul, or Number
A variable length tuple or Mul of Gates whose product is equal to
a scalar matrix
return_as_muls : bool
True to return a set of Muls; False to return a set of tuples
Examples
========
Find the gate rules of the current circuit using tuples:
>>> from sympy.physics.quantum.identitysearch import generate_gate_rules
>>> from sympy.physics.quantum.gate import X, Y, Z
>>> x = X(0); y = Y(0); z = Z(0)
>>> generate_gate_rules((x, x))
{((X(0),), (X(0),)), ((X(0), X(0)), ())}
>>> generate_gate_rules((x, y, z))
{((), (X(0), Z(0), Y(0))), ((), (Y(0), X(0), Z(0))),
((), (Z(0), Y(0), X(0))), ((X(0),), (Z(0), Y(0))),
((Y(0),), (X(0), Z(0))), ((Z(0),), (Y(0), X(0))),
((X(0), Y(0)), (Z(0),)), ((Y(0), Z(0)), (X(0),)),
((Z(0), X(0)), (Y(0),)), ((X(0), Y(0), Z(0)), ()),
((Y(0), Z(0), X(0)), ()), ((Z(0), X(0), Y(0)), ())}
Find the gate rules of the current circuit using Muls:
>>> generate_gate_rules(x*x, return_as_muls=True)
{(1, 1)}
>>> generate_gate_rules(x*y*z, return_as_muls=True)
{(1, X(0)*Z(0)*Y(0)), (1, Y(0)*X(0)*Z(0)),
(1, Z(0)*Y(0)*X(0)), (X(0)*Y(0), Z(0)),
(Y(0)*Z(0), X(0)), (Z(0)*X(0), Y(0)),
(X(0)*Y(0)*Z(0), 1), (Y(0)*Z(0)*X(0), 1),
(Z(0)*X(0)*Y(0), 1), (X(0), Z(0)*Y(0)),
(Y(0), X(0)*Z(0)), (Z(0), Y(0)*X(0))}
"""
if isinstance(gate_seq, Number):
if return_as_muls:
return {(S.One, S.One)}
else:
return {((), ())}
elif isinstance(gate_seq, Mul):
gate_seq = gate_seq.args
# Each item in queue is a 3-tuple:
# i) first item is the left side of an equality
# ii) second item is the right side of an equality
# iii) third item is the number of operations performed
# The argument, gate_seq, will start on the left side, and
# the right side will be empty, implying the presence of an
# identity.
queue = deque()
# A set of gate rules
rules = set()
# Maximum number of operations to perform
max_ops = len(gate_seq)
def process_new_rule(new_rule, ops):
if new_rule is not None:
new_left, new_right = new_rule
if new_rule not in rules and (new_right, new_left) not in rules:
rules.add(new_rule)
# If haven't reached the max limit on operations
if ops + 1 < max_ops:
queue.append(new_rule + (ops + 1,))
queue.append((gate_seq, (), 0))
rules.add((gate_seq, ()))
while len(queue) > 0:
left, right, ops = queue.popleft()
# Do a LL
new_rule = ll_op(left, right)
process_new_rule(new_rule, ops)
# Do a LR
new_rule = lr_op(left, right)
process_new_rule(new_rule, ops)
# Do a RL
new_rule = rl_op(left, right)
process_new_rule(new_rule, ops)
# Do a RR
new_rule = rr_op(left, right)
process_new_rule(new_rule, ops)
if return_as_muls:
# Convert each rule as tuples into a rule as muls
mul_rules = set()
for rule in rules:
left, right = rule
mul_rules.add((Mul(*left), Mul(*right)))
rules = mul_rules
return rules
def generate_equivalent_ids(gate_seq, return_as_muls=False):
"""Returns a set of equivalent gate identities.
A gate identity is a quantum circuit such that the product
of the gates in the circuit is equal to a scalar value.
For example, XYZ = i, where X, Y, Z are the Pauli gates and
i is the imaginary value, is considered a gate identity.
This function uses the four operations (LL, LR, RL, RR)
to generate the gate rules and, subsequently, to locate equivalent
gate identities.
Note that all equivalent identities are reachable in n operations
from the starting gate identity, where n is the number of gates
in the sequence.
The max number of gate identities is 2n, where n is the number
of gates in the sequence (unproven).
Parameters
==========
gate_seq : Gate tuple, Mul, or Number
A variable length tuple or Mul of Gates whose product is equal to
a scalar matrix.
return_as_muls: bool
True to return as Muls; False to return as tuples
Examples
========
Find equivalent gate identities from the current circuit with tuples:
>>> from sympy.physics.quantum.identitysearch import generate_equivalent_ids
>>> from sympy.physics.quantum.gate import X, Y, Z
>>> x = X(0); y = Y(0); z = Z(0)
>>> generate_equivalent_ids((x, x))
{(X(0), X(0))}
>>> generate_equivalent_ids((x, y, z))
{(X(0), Y(0), Z(0)), (X(0), Z(0), Y(0)), (Y(0), X(0), Z(0)),
(Y(0), Z(0), X(0)), (Z(0), X(0), Y(0)), (Z(0), Y(0), X(0))}
Find equivalent gate identities from the current circuit with Muls:
>>> generate_equivalent_ids(x*x, return_as_muls=True)
{1}
>>> generate_equivalent_ids(x*y*z, return_as_muls=True)
{X(0)*Y(0)*Z(0), X(0)*Z(0)*Y(0), Y(0)*X(0)*Z(0),
Y(0)*Z(0)*X(0), Z(0)*X(0)*Y(0), Z(0)*Y(0)*X(0)}
"""
if isinstance(gate_seq, Number):
return {S.One}
elif isinstance(gate_seq, Mul):
gate_seq = gate_seq.args
# Filter through the gate rules and keep the rules
# with an empty tuple either on the left or right side
# A set of equivalent gate identities
eq_ids = set()
gate_rules = generate_gate_rules(gate_seq)
for rule in gate_rules:
l, r = rule
if l == ():
eq_ids.add(r)
elif r == ():
eq_ids.add(l)
if return_as_muls:
convert_to_mul = lambda id_seq: Mul(*id_seq)
eq_ids = set(map(convert_to_mul, eq_ids))
return eq_ids
class GateIdentity(Basic):
"""Wrapper class for circuits that reduce to a scalar value.
A gate identity is a quantum circuit such that the product
of the gates in the circuit is equal to a scalar value.
For example, XYZ = i, where X, Y, Z are the Pauli gates and
i is the imaginary value, is considered a gate identity.
Parameters
==========
args : Gate tuple
A variable length tuple of Gates that form an identity.
Examples
========
Create a GateIdentity and look at its attributes:
>>> from sympy.physics.quantum.identitysearch import GateIdentity
>>> from sympy.physics.quantum.gate import X, Y, Z
>>> x = X(0); y = Y(0); z = Z(0)
>>> an_identity = GateIdentity(x, y, z)
>>> an_identity.circuit
X(0)*Y(0)*Z(0)
>>> an_identity.equivalent_ids
{(X(0), Y(0), Z(0)), (X(0), Z(0), Y(0)), (Y(0), X(0), Z(0)),
(Y(0), Z(0), X(0)), (Z(0), X(0), Y(0)), (Z(0), Y(0), X(0))}
"""
def __new__(cls, *args):
# args should be a tuple - a variable length argument list
obj = Basic.__new__(cls, *args)
obj._circuit = Mul(*args)
obj._rules = generate_gate_rules(args)
obj._eq_ids = generate_equivalent_ids(args)
return obj
@property
def circuit(self):
return self._circuit
@property
def gate_rules(self):
return self._rules
@property
def equivalent_ids(self):
return self._eq_ids
@property
def sequence(self):
return self.args
def __str__(self):
"""Returns the string of gates in a tuple."""
return str(self.circuit)
def is_degenerate(identity_set, gate_identity):
"""Checks if a gate identity is a permutation of another identity.
Parameters
==========
identity_set : set
A Python set with GateIdentity objects.
gate_identity : GateIdentity
The GateIdentity to check for existence in the set.
Examples
========
Check if the identity is a permutation of another identity:
>>> from sympy.physics.quantum.identitysearch import (
... GateIdentity, is_degenerate)
>>> from sympy.physics.quantum.gate import X, Y, Z
>>> x = X(0); y = Y(0); z = Z(0)
>>> an_identity = GateIdentity(x, y, z)
>>> id_set = {an_identity}
>>> another_id = (y, z, x)
>>> is_degenerate(id_set, another_id)
True
>>> another_id = (x, x)
>>> is_degenerate(id_set, another_id)
False
"""
# For now, just iteratively go through the set and check if the current
# gate_identity is a permutation of an identity in the set
for an_id in identity_set:
if (gate_identity in an_id.equivalent_ids):
return True
return False
def is_reducible(circuit, nqubits, begin, end):
"""Determines if a circuit is reducible by checking
if its subcircuits are scalar values.
Parameters
==========
circuit : Gate tuple
A tuple of Gates representing a circuit. The circuit to check
if a gate identity is contained in a subcircuit.
nqubits : int
The number of qubits the circuit operates on.
begin : int
The leftmost gate in the circuit to include in a subcircuit.
end : int
The rightmost gate in the circuit to include in a subcircuit.
Examples
========
Check if the circuit can be reduced:
>>> from sympy.physics.quantum.identitysearch import is_reducible
>>> from sympy.physics.quantum.gate import X, Y, Z
>>> x = X(0); y = Y(0); z = Z(0)
>>> is_reducible((x, y, z), 1, 0, 3)
True
Check if an interval in the circuit can be reduced:
>>> is_reducible((x, y, z), 1, 1, 3)
False
>>> is_reducible((x, y, y), 1, 1, 3)
True
"""
current_circuit = ()
# Start from the gate at "end" and go down to almost the gate at "begin"
for ndx in reversed(range(begin, end)):
next_gate = circuit[ndx]
current_circuit = (next_gate,) + current_circuit
# If a circuit as a matrix is equivalent to a scalar value
if (is_scalar_matrix(current_circuit, nqubits, False)):
return True
return False
def bfs_identity_search(gate_list, nqubits, max_depth=None,
identity_only=False):
"""Constructs a set of gate identities from the list of possible gates.
Performs a breadth first search over the space of gate identities.
This allows the finding of the shortest gate identities first.
Parameters
==========
gate_list : list, Gate
A list of Gates from which to search for gate identities.
nqubits : int
The number of qubits the quantum circuit operates on.
max_depth : int
The longest quantum circuit to construct from gate_list.
identity_only : bool
True to search for gate identities that reduce to identity;
False to search for gate identities that reduce to a scalar.
Examples
========
Find a list of gate identities:
>>> from sympy.physics.quantum.identitysearch import bfs_identity_search
>>> from sympy.physics.quantum.gate import X, Y, Z
>>> x = X(0); y = Y(0); z = Z(0)
>>> bfs_identity_search([x], 1, max_depth=2)
{GateIdentity(X(0), X(0))}
>>> bfs_identity_search([x, y, z], 1)
{GateIdentity(X(0), X(0)), GateIdentity(Y(0), Y(0)),
GateIdentity(Z(0), Z(0)), GateIdentity(X(0), Y(0), Z(0))}
Find a list of identities that only equal to 1:
>>> bfs_identity_search([x, y, z], 1, identity_only=True)
{GateIdentity(X(0), X(0)), GateIdentity(Y(0), Y(0)),
GateIdentity(Z(0), Z(0))}
"""
if max_depth is None or max_depth <= 0:
max_depth = len(gate_list)
id_only = identity_only
# Start with an empty sequence (implicitly contains an IdentityGate)
queue = deque([()])
# Create an empty set of gate identities
ids = set()
# Begin searching for gate identities in given space.
while (len(queue) > 0):
current_circuit = queue.popleft()
for next_gate in gate_list:
new_circuit = current_circuit + (next_gate,)
# Determines if a (strict) subcircuit is a scalar matrix
circuit_reducible = is_reducible(new_circuit, nqubits,
1, len(new_circuit))
# In many cases when the matrix is a scalar value,
# the evaluated matrix will actually be an integer
if (is_scalar_matrix(new_circuit, nqubits, id_only) and
not is_degenerate(ids, new_circuit) and
not circuit_reducible):
ids.add(GateIdentity(*new_circuit))
elif (len(new_circuit) < max_depth and
not circuit_reducible):
queue.append(new_circuit)
return ids
def random_identity_search(gate_list, numgates, nqubits):
"""Randomly selects numgates from gate_list and checks if it is
a gate identity.
If the circuit is a gate identity, the circuit is returned;
Otherwise, None is returned.
"""
gate_size = len(gate_list)
circuit = ()
for i in range(numgates):
next_gate = gate_list[randint(0, gate_size - 1)]
circuit = circuit + (next_gate,)
is_scalar = is_scalar_matrix(circuit, nqubits, False)
return circuit if is_scalar else None
PK ]ZZZZm�� � % sympy/physics/quantum/innerproduct.py"""Symbolic inner product."""
from sympy.core.expr import Expr
from sympy.functions.elementary.complexes import conjugate
from sympy.printing.pretty.stringpict import prettyForm
from sympy.physics.quantum.dagger import Dagger
from sympy.physics.quantum.state import KetBase, BraBase
__all__ = [
'InnerProduct'
]
# InnerProduct is not an QExpr because it is really just a regular commutative
# number. We have gone back and forth about this, but we gain a lot by having
# it subclass Expr. The main challenges were getting Dagger to work
# (we use _eval_conjugate) and represent (we can use atoms and subs). Having
# it be an Expr, mean that there are no commutative QExpr subclasses,
# which simplifies the design of everything.
class InnerProduct(Expr):
"""An unevaluated inner product between a Bra and a Ket [1].
Parameters
==========
bra : BraBase or subclass
The bra on the left side of the inner product.
ket : KetBase or subclass
The ket on the right side of the inner product.
Examples
========
Create an InnerProduct and check its properties:
>>> from sympy.physics.quantum import Bra, Ket
>>> b = Bra('b')
>>> k = Ket('k')
>>> ip = b*k
>>> ip
<b|k>
>>> ip.bra
<b|
>>> ip.ket
|k>
In simple products of kets and bras inner products will be automatically
identified and created::
>>> b*k
<b|k>
But in more complex expressions, there is ambiguity in whether inner or
outer products should be created::
>>> k*b*k*b
|k><b|*|k>*<b|
A user can force the creation of a inner products in a complex expression
by using parentheses to group the bra and ket::
>>> k*(b*k)*b
<b|k>*|k>*<b|
Notice how the inner product <b|k> moved to the left of the expression
because inner products are commutative complex numbers.
References
==========
.. [1] https://en.wikipedia.org/wiki/Inner_product
"""
is_complex = True
def __new__(cls, bra, ket):
if not isinstance(ket, KetBase):
raise TypeError('KetBase subclass expected, got: %r' % ket)
if not isinstance(bra, BraBase):
raise TypeError('BraBase subclass expected, got: %r' % ket)
obj = Expr.__new__(cls, bra, ket)
return obj
@property
def bra(self):
return self.args[0]
@property
def ket(self):
return self.args[1]
def _eval_conjugate(self):
return InnerProduct(Dagger(self.ket), Dagger(self.bra))
def _sympyrepr(self, printer, *args):
return '%s(%s,%s)' % (self.__class__.__name__,
printer._print(self.bra, *args), printer._print(self.ket, *args))
def _sympystr(self, printer, *args):
sbra = printer._print(self.bra)
sket = printer._print(self.ket)
return '%s|%s' % (sbra[:-1], sket[1:])
def _pretty(self, printer, *args):
# Print state contents
bra = self.bra._print_contents_pretty(printer, *args)
ket = self.ket._print_contents_pretty(printer, *args)
# Print brackets
height = max(bra.height(), ket.height())
use_unicode = printer._use_unicode
lbracket, _ = self.bra._pretty_brackets(height, use_unicode)
cbracket, rbracket = self.ket._pretty_brackets(height, use_unicode)
# Build innerproduct
pform = prettyForm(*bra.left(lbracket))
pform = prettyForm(*pform.right(cbracket))
pform = prettyForm(*pform.right(ket))
pform = prettyForm(*pform.right(rbracket))
return pform
def _latex(self, printer, *args):
bra_label = self.bra._print_contents_latex(printer, *args)
ket = printer._print(self.ket, *args)
return r'\left\langle %s \right. %s' % (bra_label, ket)
def doit(self, **hints):
try:
r = self.ket._eval_innerproduct(self.bra, **hints)
except NotImplementedError:
try:
r = conjugate(
self.bra.dual._eval_innerproduct(self.ket.dual, **hints)
)
except NotImplementedError:
r = None
if r is not None:
return r
return self
PK ]ZZZ�p� $ sympy/physics/quantum/matrixcache.py"""A cache for storing small matrices in multiple formats."""
from sympy.core.numbers import (I, Rational, pi)
from sympy.core.power import Pow
from sympy.functions.elementary.exponential import exp
from sympy.matrices.dense import Matrix
from sympy.physics.quantum.matrixutils import (
to_sympy, to_numpy, to_scipy_sparse
)
class MatrixCache:
"""A cache for small matrices in different formats.
This class takes small matrices in the standard ``sympy.Matrix`` format,
and then converts these to both ``numpy.matrix`` and
``scipy.sparse.csr_matrix`` matrices. These matrices are then stored for
future recovery.
"""
def __init__(self, dtype='complex'):
self._cache = {}
self.dtype = dtype
def cache_matrix(self, name, m):
"""Cache a matrix by its name.
Parameters
----------
name : str
A descriptive name for the matrix, like "identity2".
m : list of lists
The raw matrix data as a SymPy Matrix.
"""
try:
self._sympy_matrix(name, m)
except ImportError:
pass
try:
self._numpy_matrix(name, m)
except ImportError:
pass
try:
self._scipy_sparse_matrix(name, m)
except ImportError:
pass
def get_matrix(self, name, format):
"""Get a cached matrix by name and format.
Parameters
----------
name : str
A descriptive name for the matrix, like "identity2".
format : str
The format desired ('sympy', 'numpy', 'scipy.sparse')
"""
m = self._cache.get((name, format))
if m is not None:
return m
raise NotImplementedError(
'Matrix with name %s and format %s is not available.' %
(name, format)
)
def _store_matrix(self, name, format, m):
self._cache[(name, format)] = m
def _sympy_matrix(self, name, m):
self._store_matrix(name, 'sympy', to_sympy(m))
def _numpy_matrix(self, name, m):
m = to_numpy(m, dtype=self.dtype)
self._store_matrix(name, 'numpy', m)
def _scipy_sparse_matrix(self, name, m):
# TODO: explore different sparse formats. But sparse.kron will use
# coo in most cases, so we use that here.
m = to_scipy_sparse(m, dtype=self.dtype)
self._store_matrix(name, 'scipy.sparse', m)
sqrt2_inv = Pow(2, Rational(-1, 2), evaluate=False)
# Save the common matrices that we will need
matrix_cache = MatrixCache()
matrix_cache.cache_matrix('eye2', Matrix([[1, 0], [0, 1]]))
matrix_cache.cache_matrix('op11', Matrix([[0, 0], [0, 1]])) # |1><1|
matrix_cache.cache_matrix('op00', Matrix([[1, 0], [0, 0]])) # |0><0|
matrix_cache.cache_matrix('op10', Matrix([[0, 0], [1, 0]])) # |1><0|
matrix_cache.cache_matrix('op01', Matrix([[0, 1], [0, 0]])) # |0><1|
matrix_cache.cache_matrix('X', Matrix([[0, 1], [1, 0]]))
matrix_cache.cache_matrix('Y', Matrix([[0, -I], [I, 0]]))
matrix_cache.cache_matrix('Z', Matrix([[1, 0], [0, -1]]))
matrix_cache.cache_matrix('S', Matrix([[1, 0], [0, I]]))
matrix_cache.cache_matrix('T', Matrix([[1, 0], [0, exp(I*pi/4)]]))
matrix_cache.cache_matrix('H', sqrt2_inv*Matrix([[1, 1], [1, -1]]))
matrix_cache.cache_matrix('Hsqrt2', Matrix([[1, 1], [1, -1]]))
matrix_cache.cache_matrix(
'SWAP', Matrix([[1, 0, 0, 0], [0, 0, 1, 0], [0, 1, 0, 0], [0, 0, 0, 1]]))
matrix_cache.cache_matrix('ZX', sqrt2_inv*Matrix([[1, 1], [1, -1]]))
matrix_cache.cache_matrix('ZY', Matrix([[I, 0], [0, -I]]))
PK ]ZZZ���D $ sympy/physics/quantum/matrixutils.py"""Utilities to deal with sympy.Matrix, numpy and scipy.sparse."""
from sympy.core.expr import Expr
from sympy.core.numbers import I
from sympy.core.singleton import S
from sympy.matrices.matrixbase import MatrixBase
from sympy.matrices import eye, zeros
from sympy.external import import_module
__all__ = [
'numpy_ndarray',
'scipy_sparse_matrix',
'sympy_to_numpy',
'sympy_to_scipy_sparse',
'numpy_to_sympy',
'scipy_sparse_to_sympy',
'flatten_scalar',
'matrix_dagger',
'to_sympy',
'to_numpy',
'to_scipy_sparse',
'matrix_tensor_product',
'matrix_zeros'
]
# Conditionally define the base classes for numpy and scipy.sparse arrays
# for use in isinstance tests.
np = import_module('numpy')
if not np:
class numpy_ndarray:
pass
else:
numpy_ndarray = np.ndarray # type: ignore
scipy = import_module('scipy', import_kwargs={'fromlist': ['sparse']})
if not scipy:
class scipy_sparse_matrix:
pass
sparse = None
else:
sparse = scipy.sparse
scipy_sparse_matrix = sparse.spmatrix # type: ignore
def sympy_to_numpy(m, **options):
"""Convert a SymPy Matrix/complex number to a numpy matrix or scalar."""
if not np:
raise ImportError
dtype = options.get('dtype', 'complex')
if isinstance(m, MatrixBase):
return np.array(m.tolist(), dtype=dtype)
elif isinstance(m, Expr):
if m.is_Number or m.is_NumberSymbol or m == I:
return complex(m)
raise TypeError('Expected MatrixBase or complex scalar, got: %r' % m)
def sympy_to_scipy_sparse(m, **options):
"""Convert a SymPy Matrix/complex number to a numpy matrix or scalar."""
if not np or not sparse:
raise ImportError
dtype = options.get('dtype', 'complex')
if isinstance(m, MatrixBase):
return sparse.csr_matrix(np.array(m.tolist(), dtype=dtype))
elif isinstance(m, Expr):
if m.is_Number or m.is_NumberSymbol or m == I:
return complex(m)
raise TypeError('Expected MatrixBase or complex scalar, got: %r' % m)
def scipy_sparse_to_sympy(m, **options):
"""Convert a scipy.sparse matrix to a SymPy matrix."""
return MatrixBase(m.todense())
def numpy_to_sympy(m, **options):
"""Convert a numpy matrix to a SymPy matrix."""
return MatrixBase(m)
def to_sympy(m, **options):
"""Convert a numpy/scipy.sparse matrix to a SymPy matrix."""
if isinstance(m, MatrixBase):
return m
elif isinstance(m, numpy_ndarray):
return numpy_to_sympy(m)
elif isinstance(m, scipy_sparse_matrix):
return scipy_sparse_to_sympy(m)
elif isinstance(m, Expr):
return m
raise TypeError('Expected sympy/numpy/scipy.sparse matrix, got: %r' % m)
def to_numpy(m, **options):
"""Convert a sympy/scipy.sparse matrix to a numpy matrix."""
dtype = options.get('dtype', 'complex')
if isinstance(m, (MatrixBase, Expr)):
return sympy_to_numpy(m, dtype=dtype)
elif isinstance(m, numpy_ndarray):
return m
elif isinstance(m, scipy_sparse_matrix):
return m.todense()
raise TypeError('Expected sympy/numpy/scipy.sparse matrix, got: %r' % m)
def to_scipy_sparse(m, **options):
"""Convert a sympy/numpy matrix to a scipy.sparse matrix."""
dtype = options.get('dtype', 'complex')
if isinstance(m, (MatrixBase, Expr)):
return sympy_to_scipy_sparse(m, dtype=dtype)
elif isinstance(m, numpy_ndarray):
if not sparse:
raise ImportError
return sparse.csr_matrix(m)
elif isinstance(m, scipy_sparse_matrix):
return m
raise TypeError('Expected sympy/numpy/scipy.sparse matrix, got: %r' % m)
def flatten_scalar(e):
"""Flatten a 1x1 matrix to a scalar, return larger matrices unchanged."""
if isinstance(e, MatrixBase):
if e.shape == (1, 1):
e = e[0]
if isinstance(e, (numpy_ndarray, scipy_sparse_matrix)):
if e.shape == (1, 1):
e = complex(e[0, 0])
return e
def matrix_dagger(e):
"""Return the dagger of a sympy/numpy/scipy.sparse matrix."""
if isinstance(e, MatrixBase):
return e.H
elif isinstance(e, (numpy_ndarray, scipy_sparse_matrix)):
return e.conjugate().transpose()
raise TypeError('Expected sympy/numpy/scipy.sparse matrix, got: %r' % e)
# TODO: Move this into sympy.matricies.
def _sympy_tensor_product(*matrices):
"""Compute the kronecker product of a sequence of SymPy Matrices.
"""
from sympy.matrices.expressions.kronecker import matrix_kronecker_product
return matrix_kronecker_product(*matrices)
def _numpy_tensor_product(*product):
"""numpy version of tensor product of multiple arguments."""
if not np:
raise ImportError
answer = product[0]
for item in product[1:]:
answer = np.kron(answer, item)
return answer
def _scipy_sparse_tensor_product(*product):
"""scipy.sparse version of tensor product of multiple arguments."""
if not sparse:
raise ImportError
answer = product[0]
for item in product[1:]:
answer = sparse.kron(answer, item)
# The final matrices will just be multiplied, so csr is a good final
# sparse format.
return sparse.csr_matrix(answer)
def matrix_tensor_product(*product):
"""Compute the matrix tensor product of sympy/numpy/scipy.sparse matrices."""
if isinstance(product[0], MatrixBase):
return _sympy_tensor_product(*product)
elif isinstance(product[0], numpy_ndarray):
return _numpy_tensor_product(*product)
elif isinstance(product[0], scipy_sparse_matrix):
return _scipy_sparse_tensor_product(*product)
def _numpy_eye(n):
"""numpy version of complex eye."""
if not np:
raise ImportError
return np.array(np.eye(n, dtype='complex'))
def _scipy_sparse_eye(n):
"""scipy.sparse version of complex eye."""
if not sparse:
raise ImportError
return sparse.eye(n, n, dtype='complex')
def matrix_eye(n, **options):
"""Get the version of eye and tensor_product for a given format."""
format = options.get('format', 'sympy')
if format == 'sympy':
return eye(n)
elif format == 'numpy':
return _numpy_eye(n)
elif format == 'scipy.sparse':
return _scipy_sparse_eye(n)
raise NotImplementedError('Invalid format: %r' % format)
def _numpy_zeros(m, n, **options):
"""numpy version of zeros."""
dtype = options.get('dtype', 'float64')
if not np:
raise ImportError
return np.zeros((m, n), dtype=dtype)
def _scipy_sparse_zeros(m, n, **options):
"""scipy.sparse version of zeros."""
spmatrix = options.get('spmatrix', 'csr')
dtype = options.get('dtype', 'float64')
if not sparse:
raise ImportError
if spmatrix == 'lil':
return sparse.lil_matrix((m, n), dtype=dtype)
elif spmatrix == 'csr':
return sparse.csr_matrix((m, n), dtype=dtype)
def matrix_zeros(m, n, **options):
""""Get a zeros matrix for a given format."""
format = options.get('format', 'sympy')
if format == 'sympy':
return zeros(m, n)
elif format == 'numpy':
return _numpy_zeros(m, n, **options)
elif format == 'scipy.sparse':
return _scipy_sparse_zeros(m, n, **options)
raise NotImplementedError('Invaild format: %r' % format)
def _numpy_matrix_to_zero(e):
"""Convert a numpy zero matrix to the zero scalar."""
if not np:
raise ImportError
test = np.zeros_like(e)
if np.allclose(e, test):
return 0.0
else:
return e
def _scipy_sparse_matrix_to_zero(e):
"""Convert a scipy.sparse zero matrix to the zero scalar."""
if not np:
raise ImportError
edense = e.todense()
test = np.zeros_like(edense)
if np.allclose(edense, test):
return 0.0
else:
return e
def matrix_to_zero(e):
"""Convert a zero matrix to the scalar zero."""
if isinstance(e, MatrixBase):
if zeros(*e.shape) == e:
e = S.Zero
elif isinstance(e, numpy_ndarray):
e = _numpy_matrix_to_zero(e)
elif isinstance(e, scipy_sparse_matrix):
e = _scipy_sparse_matrix_to_zero(e)
return e
PK ]ZZZ��ndL dL ! sympy/physics/quantum/operator.py"""Quantum mechanical operators.
TODO:
* Fix early 0 in apply_operators.
* Debug and test apply_operators.
* Get cse working with classes in this file.
* Doctests and documentation of special methods for InnerProduct, Commutator,
AntiCommutator, represent, apply_operators.
"""
from typing import Optional
from sympy.core.add import Add
from sympy.core.expr import Expr
from sympy.core.function import (Derivative, expand)
from sympy.core.mul import Mul
from sympy.core.numbers import oo
from sympy.core.singleton import S
from sympy.printing.pretty.stringpict import prettyForm
from sympy.physics.quantum.dagger import Dagger
from sympy.physics.quantum.qexpr import QExpr, dispatch_method
from sympy.matrices import eye
__all__ = [
'Operator',
'HermitianOperator',
'UnitaryOperator',
'IdentityOperator',
'OuterProduct',
'DifferentialOperator'
]
#-----------------------------------------------------------------------------
# Operators and outer products
#-----------------------------------------------------------------------------
class Operator(QExpr):
"""Base class for non-commuting quantum operators.
An operator maps between quantum states [1]_. In quantum mechanics,
observables (including, but not limited to, measured physical values) are
represented as Hermitian operators [2]_.
Parameters
==========
args : tuple
The list of numbers or parameters that uniquely specify the
operator. For time-dependent operators, this will include the time.
Examples
========
Create an operator and examine its attributes::
>>> from sympy.physics.quantum import Operator
>>> from sympy import I
>>> A = Operator('A')
>>> A
A
>>> A.hilbert_space
H
>>> A.label
(A,)
>>> A.is_commutative
False
Create another operator and do some arithmetic operations::
>>> B = Operator('B')
>>> C = 2*A*A + I*B
>>> C
2*A**2 + I*B
Operators do not commute::
>>> A.is_commutative
False
>>> B.is_commutative
False
>>> A*B == B*A
False
Polymonials of operators respect the commutation properties::
>>> e = (A+B)**3
>>> e.expand()
A*B*A + A*B**2 + A**2*B + A**3 + B*A*B + B*A**2 + B**2*A + B**3
Operator inverses are handle symbolically::
>>> A.inv()
A**(-1)
>>> A*A.inv()
1
References
==========
.. [1] https://en.wikipedia.org/wiki/Operator_%28physics%29
.. [2] https://en.wikipedia.org/wiki/Observable
"""
is_hermitian: Optional[bool] = None
is_unitary: Optional[bool] = None
@classmethod
def default_args(self):
return ("O",)
#-------------------------------------------------------------------------
# Printing
#-------------------------------------------------------------------------
_label_separator = ','
def _print_operator_name(self, printer, *args):
return self.__class__.__name__
_print_operator_name_latex = _print_operator_name
def _print_operator_name_pretty(self, printer, *args):
return prettyForm(self.__class__.__name__)
def _print_contents(self, printer, *args):
if len(self.label) == 1:
return self._print_label(printer, *args)
else:
return '%s(%s)' % (
self._print_operator_name(printer, *args),
self._print_label(printer, *args)
)
def _print_contents_pretty(self, printer, *args):
if len(self.label) == 1:
return self._print_label_pretty(printer, *args)
else:
pform = self._print_operator_name_pretty(printer, *args)
label_pform = self._print_label_pretty(printer, *args)
label_pform = prettyForm(
*label_pform.parens(left='(', right=')')
)
pform = prettyForm(*pform.right(label_pform))
return pform
def _print_contents_latex(self, printer, *args):
if len(self.label) == 1:
return self._print_label_latex(printer, *args)
else:
return r'%s\left(%s\right)' % (
self._print_operator_name_latex(printer, *args),
self._print_label_latex(printer, *args)
)
#-------------------------------------------------------------------------
# _eval_* methods
#-------------------------------------------------------------------------
def _eval_commutator(self, other, **options):
"""Evaluate [self, other] if known, return None if not known."""
return dispatch_method(self, '_eval_commutator', other, **options)
def _eval_anticommutator(self, other, **options):
"""Evaluate [self, other] if known."""
return dispatch_method(self, '_eval_anticommutator', other, **options)
#-------------------------------------------------------------------------
# Operator application
#-------------------------------------------------------------------------
def _apply_operator(self, ket, **options):
return dispatch_method(self, '_apply_operator', ket, **options)
def _apply_from_right_to(self, bra, **options):
return None
def matrix_element(self, *args):
raise NotImplementedError('matrix_elements is not defined')
def inverse(self):
return self._eval_inverse()
inv = inverse
def _eval_inverse(self):
return self**(-1)
def __mul__(self, other):
if isinstance(other, IdentityOperator):
return self
return Mul(self, other)
class HermitianOperator(Operator):
"""A Hermitian operator that satisfies H == Dagger(H).
Parameters
==========
args : tuple
The list of numbers or parameters that uniquely specify the
operator. For time-dependent operators, this will include the time.
Examples
========
>>> from sympy.physics.quantum import Dagger, HermitianOperator
>>> H = HermitianOperator('H')
>>> Dagger(H)
H
"""
is_hermitian = True
def _eval_inverse(self):
if isinstance(self, UnitaryOperator):
return self
else:
return Operator._eval_inverse(self)
def _eval_power(self, exp):
if isinstance(self, UnitaryOperator):
# so all eigenvalues of self are 1 or -1
if exp.is_even:
from sympy.core.singleton import S
return S.One # is identity, see Issue 24153.
elif exp.is_odd:
return self
# No simplification in all other cases
return Operator._eval_power(self, exp)
class UnitaryOperator(Operator):
"""A unitary operator that satisfies U*Dagger(U) == 1.
Parameters
==========
args : tuple
The list of numbers or parameters that uniquely specify the
operator. For time-dependent operators, this will include the time.
Examples
========
>>> from sympy.physics.quantum import Dagger, UnitaryOperator
>>> U = UnitaryOperator('U')
>>> U*Dagger(U)
1
"""
is_unitary = True
def _eval_adjoint(self):
return self._eval_inverse()
class IdentityOperator(Operator):
"""An identity operator I that satisfies op * I == I * op == op for any
operator op.
Parameters
==========
N : Integer
Optional parameter that specifies the dimension of the Hilbert space
of operator. This is used when generating a matrix representation.
Examples
========
>>> from sympy.physics.quantum import IdentityOperator
>>> IdentityOperator()
I
"""
is_hermitian = True
is_unitary = True
@property
def dimension(self):
return self.N
@classmethod
def default_args(self):
return (oo,)
def __init__(self, *args, **hints):
if not len(args) in (0, 1):
raise ValueError('0 or 1 parameters expected, got %s' % args)
self.N = args[0] if (len(args) == 1 and args[0]) else oo
def _eval_commutator(self, other, **hints):
return S.Zero
def _eval_anticommutator(self, other, **hints):
return 2 * other
def _eval_inverse(self):
return self
def _eval_adjoint(self):
return self
def _apply_operator(self, ket, **options):
return ket
def _apply_from_right_to(self, bra, **options):
return bra
def _eval_power(self, exp):
return self
def _print_contents(self, printer, *args):
return 'I'
def _print_contents_pretty(self, printer, *args):
return prettyForm('I')
def _print_contents_latex(self, printer, *args):
return r'{\mathcal{I}}'
def __mul__(self, other):
if isinstance(other, (Operator, Dagger)):
return other
return Mul(self, other)
def _represent_default_basis(self, **options):
if not self.N or self.N == oo:
raise NotImplementedError('Cannot represent infinite dimensional' +
' identity operator as a matrix')
format = options.get('format', 'sympy')
if format != 'sympy':
raise NotImplementedError('Representation in format ' +
'%s not implemented.' % format)
return eye(self.N)
class OuterProduct(Operator):
"""An unevaluated outer product between a ket and bra.
This constructs an outer product between any subclass of ``KetBase`` and
``BraBase`` as ``|a><b|``. An ``OuterProduct`` inherits from Operator as they act as
operators in quantum expressions. For reference see [1]_.
Parameters
==========
ket : KetBase
The ket on the left side of the outer product.
bar : BraBase
The bra on the right side of the outer product.
Examples
========
Create a simple outer product by hand and take its dagger::
>>> from sympy.physics.quantum import Ket, Bra, OuterProduct, Dagger
>>> from sympy.physics.quantum import Operator
>>> k = Ket('k')
>>> b = Bra('b')
>>> op = OuterProduct(k, b)
>>> op
|k><b|
>>> op.hilbert_space
H
>>> op.ket
|k>
>>> op.bra
<b|
>>> Dagger(op)
|b><k|
In simple products of kets and bras outer products will be automatically
identified and created::
>>> k*b
|k><b|
But in more complex expressions, outer products are not automatically
created::
>>> A = Operator('A')
>>> A*k*b
A*|k>*<b|
A user can force the creation of an outer product in a complex expression
by using parentheses to group the ket and bra::
>>> A*(k*b)
A*|k><b|
References
==========
.. [1] https://en.wikipedia.org/wiki/Outer_product
"""
is_commutative = False
def __new__(cls, *args, **old_assumptions):
from sympy.physics.quantum.state import KetBase, BraBase
if len(args) != 2:
raise ValueError('2 parameters expected, got %d' % len(args))
ket_expr = expand(args[0])
bra_expr = expand(args[1])
if (isinstance(ket_expr, (KetBase, Mul)) and
isinstance(bra_expr, (BraBase, Mul))):
ket_c, kets = ket_expr.args_cnc()
bra_c, bras = bra_expr.args_cnc()
if len(kets) != 1 or not isinstance(kets[0], KetBase):
raise TypeError('KetBase subclass expected'
', got: %r' % Mul(*kets))
if len(bras) != 1 or not isinstance(bras[0], BraBase):
raise TypeError('BraBase subclass expected'
', got: %r' % Mul(*bras))
if not kets[0].dual_class() == bras[0].__class__:
raise TypeError(
'ket and bra are not dual classes: %r, %r' %
(kets[0].__class__, bras[0].__class__)
)
# TODO: make sure the hilbert spaces of the bra and ket are
# compatible
obj = Expr.__new__(cls, *(kets[0], bras[0]), **old_assumptions)
obj.hilbert_space = kets[0].hilbert_space
return Mul(*(ket_c + bra_c)) * obj
op_terms = []
if isinstance(ket_expr, Add) and isinstance(bra_expr, Add):
for ket_term in ket_expr.args:
for bra_term in bra_expr.args:
op_terms.append(OuterProduct(ket_term, bra_term,
**old_assumptions))
elif isinstance(ket_expr, Add):
for ket_term in ket_expr.args:
op_terms.append(OuterProduct(ket_term, bra_expr,
**old_assumptions))
elif isinstance(bra_expr, Add):
for bra_term in bra_expr.args:
op_terms.append(OuterProduct(ket_expr, bra_term,
**old_assumptions))
else:
raise TypeError(
'Expected ket and bra expression, got: %r, %r' %
(ket_expr, bra_expr)
)
return Add(*op_terms)
@property
def ket(self):
"""Return the ket on the left side of the outer product."""
return self.args[0]
@property
def bra(self):
"""Return the bra on the right side of the outer product."""
return self.args[1]
def _eval_adjoint(self):
return OuterProduct(Dagger(self.bra), Dagger(self.ket))
def _sympystr(self, printer, *args):
return printer._print(self.ket) + printer._print(self.bra)
def _sympyrepr(self, printer, *args):
return '%s(%s,%s)' % (self.__class__.__name__,
printer._print(self.ket, *args), printer._print(self.bra, *args))
def _pretty(self, printer, *args):
pform = self.ket._pretty(printer, *args)
return prettyForm(*pform.right(self.bra._pretty(printer, *args)))
def _latex(self, printer, *args):
k = printer._print(self.ket, *args)
b = printer._print(self.bra, *args)
return k + b
def _represent(self, **options):
k = self.ket._represent(**options)
b = self.bra._represent(**options)
return k*b
def _eval_trace(self, **kwargs):
# TODO if operands are tensorproducts this may be will be handled
# differently.
return self.ket._eval_trace(self.bra, **kwargs)
class DifferentialOperator(Operator):
"""An operator for representing the differential operator, i.e. d/dx
It is initialized by passing two arguments. The first is an arbitrary
expression that involves a function, such as ``Derivative(f(x), x)``. The
second is the function (e.g. ``f(x)``) which we are to replace with the
``Wavefunction`` that this ``DifferentialOperator`` is applied to.
Parameters
==========
expr : Expr
The arbitrary expression which the appropriate Wavefunction is to be
substituted into
func : Expr
A function (e.g. f(x)) which is to be replaced with the appropriate
Wavefunction when this DifferentialOperator is applied
Examples
========
You can define a completely arbitrary expression and specify where the
Wavefunction is to be substituted
>>> from sympy import Derivative, Function, Symbol
>>> from sympy.physics.quantum.operator import DifferentialOperator
>>> from sympy.physics.quantum.state import Wavefunction
>>> from sympy.physics.quantum.qapply import qapply
>>> f = Function('f')
>>> x = Symbol('x')
>>> d = DifferentialOperator(1/x*Derivative(f(x), x), f(x))
>>> w = Wavefunction(x**2, x)
>>> d.function
f(x)
>>> d.variables
(x,)
>>> qapply(d*w)
Wavefunction(2, x)
"""
@property
def variables(self):
"""
Returns the variables with which the function in the specified
arbitrary expression is evaluated
Examples
========
>>> from sympy.physics.quantum.operator import DifferentialOperator
>>> from sympy import Symbol, Function, Derivative
>>> x = Symbol('x')
>>> f = Function('f')
>>> d = DifferentialOperator(1/x*Derivative(f(x), x), f(x))
>>> d.variables
(x,)
>>> y = Symbol('y')
>>> d = DifferentialOperator(Derivative(f(x, y), x) +
... Derivative(f(x, y), y), f(x, y))
>>> d.variables
(x, y)
"""
return self.args[-1].args
@property
def function(self):
"""
Returns the function which is to be replaced with the Wavefunction
Examples
========
>>> from sympy.physics.quantum.operator import DifferentialOperator
>>> from sympy import Function, Symbol, Derivative
>>> x = Symbol('x')
>>> f = Function('f')
>>> d = DifferentialOperator(Derivative(f(x), x), f(x))
>>> d.function
f(x)
>>> y = Symbol('y')
>>> d = DifferentialOperator(Derivative(f(x, y), x) +
... Derivative(f(x, y), y), f(x, y))
>>> d.function
f(x, y)
"""
return self.args[-1]
@property
def expr(self):
"""
Returns the arbitrary expression which is to have the Wavefunction
substituted into it
Examples
========
>>> from sympy.physics.quantum.operator import DifferentialOperator
>>> from sympy import Function, Symbol, Derivative
>>> x = Symbol('x')
>>> f = Function('f')
>>> d = DifferentialOperator(Derivative(f(x), x), f(x))
>>> d.expr
Derivative(f(x), x)
>>> y = Symbol('y')
>>> d = DifferentialOperator(Derivative(f(x, y), x) +
... Derivative(f(x, y), y), f(x, y))
>>> d.expr
Derivative(f(x, y), x) + Derivative(f(x, y), y)
"""
return self.args[0]
@property
def free_symbols(self):
"""
Return the free symbols of the expression.
"""
return self.expr.free_symbols
def _apply_operator_Wavefunction(self, func, **options):
from sympy.physics.quantum.state import Wavefunction
var = self.variables
wf_vars = func.args[1:]
f = self.function
new_expr = self.expr.subs(f, func(*var))
new_expr = new_expr.doit()
return Wavefunction(new_expr, *wf_vars)
def _eval_derivative(self, symbol):
new_expr = Derivative(self.expr, symbol)
return DifferentialOperator(new_expr, self.args[-1])
#-------------------------------------------------------------------------
# Printing
#-------------------------------------------------------------------------
def _print(self, printer, *args):
return '%s(%s)' % (
self._print_operator_name(printer, *args),
self._print_label(printer, *args)
)
def _print_pretty(self, printer, *args):
pform = self._print_operator_name_pretty(printer, *args)
label_pform = self._print_label_pretty(printer, *args)
label_pform = prettyForm(
*label_pform.parens(left='(', right=')')
)
pform = prettyForm(*pform.right(label_pform))
return pform
PK ]ZZZ)�* 8( 8( ) sympy/physics/quantum/operatorordering.py"""Functions for reordering operator expressions."""
import warnings
from sympy.core.add import Add
from sympy.core.mul import Mul
from sympy.core.numbers import Integer
from sympy.core.power import Pow
from sympy.physics.quantum import Commutator, AntiCommutator
from sympy.physics.quantum.boson import BosonOp
from sympy.physics.quantum.fermion import FermionOp
__all__ = [
'normal_order',
'normal_ordered_form'
]
def _expand_powers(factors):
"""
Helper function for normal_ordered_form and normal_order: Expand a
power expression to a multiplication expression so that that the
expression can be handled by the normal ordering functions.
"""
new_factors = []
for factor in factors.args:
if (isinstance(factor, Pow)
and isinstance(factor.args[1], Integer)
and factor.args[1] > 0):
for n in range(factor.args[1]):
new_factors.append(factor.args[0])
else:
new_factors.append(factor)
return new_factors
def _normal_ordered_form_factor(product, independent=False, recursive_limit=10,
_recursive_depth=0):
"""
Helper function for normal_ordered_form_factor: Write multiplication
expression with bosonic or fermionic operators on normally ordered form,
using the bosonic and fermionic commutation relations. The resulting
operator expression is equivalent to the argument, but will in general be
a sum of operator products instead of a simple product.
"""
factors = _expand_powers(product)
new_factors = []
n = 0
while n < len(factors) - 1:
current, next = factors[n], factors[n + 1]
if any(not isinstance(f, (FermionOp, BosonOp)) for f in (current, next)):
new_factors.append(current)
n += 1
continue
key_1 = (current.is_annihilation, str(current.name))
key_2 = (next.is_annihilation, str(next.name))
if key_1 <= key_2:
new_factors.append(current)
n += 1
continue
n += 2
if current.is_annihilation and not next.is_annihilation:
if isinstance(current, BosonOp) and isinstance(next, BosonOp):
if current.args[0] != next.args[0]:
if independent:
c = 0
else:
c = Commutator(current, next)
new_factors.append(next * current + c)
else:
new_factors.append(next * current + 1)
elif isinstance(current, FermionOp) and isinstance(next, FermionOp):
if current.args[0] != next.args[0]:
if independent:
c = 0
else:
c = AntiCommutator(current, next)
new_factors.append(-next * current + c)
else:
new_factors.append(-next * current + 1)
elif (current.is_annihilation == next.is_annihilation and
isinstance(current, FermionOp) and isinstance(next, FermionOp)):
new_factors.append(-next * current)
else:
new_factors.append(next * current)
if n == len(factors) - 1:
new_factors.append(factors[-1])
if new_factors == factors:
return product
else:
expr = Mul(*new_factors).expand()
return normal_ordered_form(expr,
recursive_limit=recursive_limit,
_recursive_depth=_recursive_depth + 1,
independent=independent)
def _normal_ordered_form_terms(expr, independent=False, recursive_limit=10,
_recursive_depth=0):
"""
Helper function for normal_ordered_form: loop through each term in an
addition expression and call _normal_ordered_form_factor to perform the
factor to an normally ordered expression.
"""
new_terms = []
for term in expr.args:
if isinstance(term, Mul):
new_term = _normal_ordered_form_factor(
term, recursive_limit=recursive_limit,
_recursive_depth=_recursive_depth, independent=independent)
new_terms.append(new_term)
else:
new_terms.append(term)
return Add(*new_terms)
def normal_ordered_form(expr, independent=False, recursive_limit=10,
_recursive_depth=0):
"""Write an expression with bosonic or fermionic operators on normal
ordered form, where each term is normally ordered. Note that this
normal ordered form is equivalent to the original expression.
Parameters
==========
expr : expression
The expression write on normal ordered form.
independent : bool (default False)
Whether to consider operator with different names as operating in
different Hilbert spaces. If False, the (anti-)commutation is left
explicit.
recursive_limit : int (default 10)
The number of allowed recursive applications of the function.
Examples
========
>>> from sympy.physics.quantum import Dagger
>>> from sympy.physics.quantum.boson import BosonOp
>>> from sympy.physics.quantum.operatorordering import normal_ordered_form
>>> a = BosonOp("a")
>>> normal_ordered_form(a * Dagger(a))
1 + Dagger(a)*a
"""
if _recursive_depth > recursive_limit:
warnings.warn("Too many recursions, aborting")
return expr
if isinstance(expr, Add):
return _normal_ordered_form_terms(expr,
recursive_limit=recursive_limit,
_recursive_depth=_recursive_depth,
independent=independent)
elif isinstance(expr, Mul):
return _normal_ordered_form_factor(expr,
recursive_limit=recursive_limit,
_recursive_depth=_recursive_depth,
independent=independent)
else:
return expr
def _normal_order_factor(product, recursive_limit=10, _recursive_depth=0):
"""
Helper function for normal_order: Normal order a multiplication expression
with bosonic or fermionic operators. In general the resulting operator
expression will not be equivalent to original product.
"""
factors = _expand_powers(product)
n = 0
new_factors = []
while n < len(factors) - 1:
if (isinstance(factors[n], BosonOp) and
factors[n].is_annihilation):
# boson
if not isinstance(factors[n + 1], BosonOp):
new_factors.append(factors[n])
else:
if factors[n + 1].is_annihilation:
new_factors.append(factors[n])
else:
if factors[n].args[0] != factors[n + 1].args[0]:
new_factors.append(factors[n + 1] * factors[n])
else:
new_factors.append(factors[n + 1] * factors[n])
n += 1
elif (isinstance(factors[n], FermionOp) and
factors[n].is_annihilation):
# fermion
if not isinstance(factors[n + 1], FermionOp):
new_factors.append(factors[n])
else:
if factors[n + 1].is_annihilation:
new_factors.append(factors[n])
else:
if factors[n].args[0] != factors[n + 1].args[0]:
new_factors.append(-factors[n + 1] * factors[n])
else:
new_factors.append(-factors[n + 1] * factors[n])
n += 1
else:
new_factors.append(factors[n])
n += 1
if n == len(factors) - 1:
new_factors.append(factors[-1])
if new_factors == factors:
return product
else:
expr = Mul(*new_factors).expand()
return normal_order(expr,
recursive_limit=recursive_limit,
_recursive_depth=_recursive_depth + 1)
def _normal_order_terms(expr, recursive_limit=10, _recursive_depth=0):
"""
Helper function for normal_order: look through each term in an addition
expression and call _normal_order_factor to perform the normal ordering
on the factors.
"""
new_terms = []
for term in expr.args:
if isinstance(term, Mul):
new_term = _normal_order_factor(term,
recursive_limit=recursive_limit,
_recursive_depth=_recursive_depth)
new_terms.append(new_term)
else:
new_terms.append(term)
return Add(*new_terms)
def normal_order(expr, recursive_limit=10, _recursive_depth=0):
"""Normal order an expression with bosonic or fermionic operators. Note
that this normal order is not equivalent to the original expression, but
the creation and annihilation operators in each term in expr is reordered
so that the expression becomes normal ordered.
Parameters
==========
expr : expression
The expression to normal order.
recursive_limit : int (default 10)
The number of allowed recursive applications of the function.
Examples
========
>>> from sympy.physics.quantum import Dagger
>>> from sympy.physics.quantum.boson import BosonOp
>>> from sympy.physics.quantum.operatorordering import normal_order
>>> a = BosonOp("a")
>>> normal_order(a * Dagger(a))
Dagger(a)*a
"""
if _recursive_depth > recursive_limit:
warnings.warn("Too many recursions, aborting")
return expr
if isinstance(expr, Add):
return _normal_order_terms(expr, recursive_limit=recursive_limit,
_recursive_depth=_recursive_depth)
elif isinstance(expr, Mul):
return _normal_order_factor(expr, recursive_limit=recursive_limit,
_recursive_depth=_recursive_depth)
else:
return expr
PK ]ZZZ`�s [% [% $ sympy/physics/quantum/operatorset.py""" A module for mapping operators to their corresponding eigenstates
and vice versa
It contains a global dictionary with eigenstate-operator pairings.
If a new state-operator pair is created, this dictionary should be
updated as well.
It also contains functions operators_to_state and state_to_operators
for mapping between the two. These can handle both classes and
instances of operators and states. See the individual function
descriptions for details.
TODO List:
- Update the dictionary with a complete list of state-operator pairs
"""
from sympy.physics.quantum.cartesian import (XOp, YOp, ZOp, XKet, PxOp, PxKet,
PositionKet3D)
from sympy.physics.quantum.operator import Operator
from sympy.physics.quantum.state import StateBase, BraBase, Ket
from sympy.physics.quantum.spin import (JxOp, JyOp, JzOp, J2Op, JxKet, JyKet,
JzKet)
__all__ = [
'operators_to_state',
'state_to_operators'
]
#state_mapping stores the mappings between states and their associated
#operators or tuples of operators. This should be updated when new
#classes are written! Entries are of the form PxKet : PxOp or
#something like 3DKet : (ROp, ThetaOp, PhiOp)
#frozenset is used so that the reverse mapping can be made
#(regular sets are not hashable because they are mutable
state_mapping = { JxKet: frozenset((J2Op, JxOp)),
JyKet: frozenset((J2Op, JyOp)),
JzKet: frozenset((J2Op, JzOp)),
Ket: Operator,
PositionKet3D: frozenset((XOp, YOp, ZOp)),
PxKet: PxOp,
XKet: XOp }
op_mapping = {v: k for k, v in state_mapping.items()}
def operators_to_state(operators, **options):
""" Returns the eigenstate of the given operator or set of operators
A global function for mapping operator classes to their associated
states. It takes either an Operator or a set of operators and
returns the state associated with these.
This function can handle both instances of a given operator or
just the class itself (i.e. both XOp() and XOp)
There are multiple use cases to consider:
1) A class or set of classes is passed: First, we try to
instantiate default instances for these operators. If this fails,
then the class is simply returned. If we succeed in instantiating
default instances, then we try to call state._operators_to_state
on the operator instances. If this fails, the class is returned.
Otherwise, the instance returned by _operators_to_state is returned.
2) An instance or set of instances is passed: In this case,
state._operators_to_state is called on the instances passed. If
this fails, a state class is returned. If the method returns an
instance, that instance is returned.
In both cases, if the operator class or set does not exist in the
state_mapping dictionary, None is returned.
Parameters
==========
arg: Operator or set
The class or instance of the operator or set of operators
to be mapped to a state
Examples
========
>>> from sympy.physics.quantum.cartesian import XOp, PxOp
>>> from sympy.physics.quantum.operatorset import operators_to_state
>>> from sympy.physics.quantum.operator import Operator
>>> operators_to_state(XOp)
|x>
>>> operators_to_state(XOp())
|x>
>>> operators_to_state(PxOp)
|px>
>>> operators_to_state(PxOp())
|px>
>>> operators_to_state(Operator)
|psi>
>>> operators_to_state(Operator())
|psi>
"""
if not (isinstance(operators, (Operator, set)) or issubclass(operators, Operator)):
raise NotImplementedError("Argument is not an Operator or a set!")
if isinstance(operators, set):
for s in operators:
if not (isinstance(s, Operator)
or issubclass(s, Operator)):
raise NotImplementedError("Set is not all Operators!")
ops = frozenset(operators)
if ops in op_mapping: # ops is a list of classes in this case
#Try to get an object from default instances of the
#operators...if this fails, return the class
try:
op_instances = [op() for op in ops]
ret = _get_state(op_mapping[ops], set(op_instances), **options)
except NotImplementedError:
ret = op_mapping[ops]
return ret
else:
tmp = [type(o) for o in ops]
classes = frozenset(tmp)
if classes in op_mapping:
ret = _get_state(op_mapping[classes], ops, **options)
else:
ret = None
return ret
else:
if operators in op_mapping:
try:
op_instance = operators()
ret = _get_state(op_mapping[operators], op_instance, **options)
except NotImplementedError:
ret = op_mapping[operators]
return ret
elif type(operators) in op_mapping:
return _get_state(op_mapping[type(operators)], operators, **options)
else:
return None
def state_to_operators(state, **options):
""" Returns the operator or set of operators corresponding to the
given eigenstate
A global function for mapping state classes to their associated
operators or sets of operators. It takes either a state class
or instance.
This function can handle both instances of a given state or just
the class itself (i.e. both XKet() and XKet)
There are multiple use cases to consider:
1) A state class is passed: In this case, we first try
instantiating a default instance of the class. If this succeeds,
then we try to call state._state_to_operators on that instance.
If the creation of the default instance or if the calling of
_state_to_operators fails, then either an operator class or set of
operator classes is returned. Otherwise, the appropriate
operator instances are returned.
2) A state instance is returned: Here, state._state_to_operators
is called for the instance. If this fails, then a class or set of
operator classes is returned. Otherwise, the instances are returned.
In either case, if the state's class does not exist in
state_mapping, None is returned.
Parameters
==========
arg: StateBase class or instance (or subclasses)
The class or instance of the state to be mapped to an
operator or set of operators
Examples
========
>>> from sympy.physics.quantum.cartesian import XKet, PxKet, XBra, PxBra
>>> from sympy.physics.quantum.operatorset import state_to_operators
>>> from sympy.physics.quantum.state import Ket, Bra
>>> state_to_operators(XKet)
X
>>> state_to_operators(XKet())
X
>>> state_to_operators(PxKet)
Px
>>> state_to_operators(PxKet())
Px
>>> state_to_operators(PxBra)
Px
>>> state_to_operators(XBra)
X
>>> state_to_operators(Ket)
O
>>> state_to_operators(Bra)
O
"""
if not (isinstance(state, StateBase) or issubclass(state, StateBase)):
raise NotImplementedError("Argument is not a state!")
if state in state_mapping: # state is a class
state_inst = _make_default(state)
try:
ret = _get_ops(state_inst,
_make_set(state_mapping[state]), **options)
except (NotImplementedError, TypeError):
ret = state_mapping[state]
elif type(state) in state_mapping:
ret = _get_ops(state,
_make_set(state_mapping[type(state)]), **options)
elif isinstance(state, BraBase) and state.dual_class() in state_mapping:
ret = _get_ops(state,
_make_set(state_mapping[state.dual_class()]))
elif issubclass(state, BraBase) and state.dual_class() in state_mapping:
state_inst = _make_default(state)
try:
ret = _get_ops(state_inst,
_make_set(state_mapping[state.dual_class()]))
except (NotImplementedError, TypeError):
ret = state_mapping[state.dual_class()]
else:
ret = None
return _make_set(ret)
def _make_default(expr):
# XXX: Catching TypeError like this is a bad way of distinguishing between
# classes and instances. The logic using this function should be rewritten
# somehow.
try:
ret = expr()
except TypeError:
ret = expr
return ret
def _get_state(state_class, ops, **options):
# Try to get a state instance from the operator INSTANCES.
# If this fails, get the class
try:
ret = state_class._operators_to_state(ops, **options)
except NotImplementedError:
ret = _make_default(state_class)
return ret
def _get_ops(state_inst, op_classes, **options):
# Try to get operator instances from the state INSTANCE.
# If this fails, just return the classes
try:
ret = state_inst._state_to_operators(op_classes, **options)
except NotImplementedError:
if isinstance(op_classes, (set, tuple, frozenset)):
ret = tuple(_make_default(x) for x in op_classes)
else:
ret = _make_default(op_classes)
if isinstance(ret, set) and len(ret) == 1:
return ret[0]
return ret
def _make_set(ops):
if isinstance(ops, (tuple, list, frozenset)):
return set(ops)
else:
return ops
PK ]ZZZi�u�bC bC sympy/physics/quantum/pauli.py"""Pauli operators and states"""
from sympy.core.add import Add
from sympy.core.mul import Mul
from sympy.core.numbers import I
from sympy.core.power import Pow
from sympy.core.singleton import S
from sympy.functions.elementary.exponential import exp
from sympy.physics.quantum import Operator, Ket, Bra
from sympy.physics.quantum import ComplexSpace
from sympy.matrices import Matrix
from sympy.functions.special.tensor_functions import KroneckerDelta
__all__ = [
'SigmaX', 'SigmaY', 'SigmaZ', 'SigmaMinus', 'SigmaPlus', 'SigmaZKet',
'SigmaZBra', 'qsimplify_pauli'
]
class SigmaOpBase(Operator):
"""Pauli sigma operator, base class"""
@property
def name(self):
return self.args[0]
@property
def use_name(self):
return bool(self.args[0]) is not False
@classmethod
def default_args(self):
return (False,)
def __new__(cls, *args, **hints):
return Operator.__new__(cls, *args, **hints)
def _eval_commutator_BosonOp(self, other, **hints):
return S.Zero
class SigmaX(SigmaOpBase):
"""Pauli sigma x operator
Parameters
==========
name : str
An optional string that labels the operator. Pauli operators with
different names commute.
Examples
========
>>> from sympy.physics.quantum import represent
>>> from sympy.physics.quantum.pauli import SigmaX
>>> sx = SigmaX()
>>> sx
SigmaX()
>>> represent(sx)
Matrix([
[0, 1],
[1, 0]])
"""
def __new__(cls, *args, **hints):
return SigmaOpBase.__new__(cls, *args, **hints)
def _eval_commutator_SigmaY(self, other, **hints):
if self.name != other.name:
return S.Zero
else:
return 2 * I * SigmaZ(self.name)
def _eval_commutator_SigmaZ(self, other, **hints):
if self.name != other.name:
return S.Zero
else:
return - 2 * I * SigmaY(self.name)
def _eval_commutator_BosonOp(self, other, **hints):
return S.Zero
def _eval_anticommutator_SigmaY(self, other, **hints):
return S.Zero
def _eval_anticommutator_SigmaZ(self, other, **hints):
return S.Zero
def _eval_adjoint(self):
return self
def _print_contents_latex(self, printer, *args):
if self.use_name:
return r'{\sigma_x^{(%s)}}' % str(self.name)
else:
return r'{\sigma_x}'
def _print_contents(self, printer, *args):
return 'SigmaX()'
def _eval_power(self, e):
if e.is_Integer and e.is_positive:
return SigmaX(self.name).__pow__(int(e) % 2)
def _represent_default_basis(self, **options):
format = options.get('format', 'sympy')
if format == 'sympy':
return Matrix([[0, 1], [1, 0]])
else:
raise NotImplementedError('Representation in format ' +
format + ' not implemented.')
class SigmaY(SigmaOpBase):
"""Pauli sigma y operator
Parameters
==========
name : str
An optional string that labels the operator. Pauli operators with
different names commute.
Examples
========
>>> from sympy.physics.quantum import represent
>>> from sympy.physics.quantum.pauli import SigmaY
>>> sy = SigmaY()
>>> sy
SigmaY()
>>> represent(sy)
Matrix([
[0, -I],
[I, 0]])
"""
def __new__(cls, *args, **hints):
return SigmaOpBase.__new__(cls, *args)
def _eval_commutator_SigmaZ(self, other, **hints):
if self.name != other.name:
return S.Zero
else:
return 2 * I * SigmaX(self.name)
def _eval_commutator_SigmaX(self, other, **hints):
if self.name != other.name:
return S.Zero
else:
return - 2 * I * SigmaZ(self.name)
def _eval_anticommutator_SigmaX(self, other, **hints):
return S.Zero
def _eval_anticommutator_SigmaZ(self, other, **hints):
return S.Zero
def _eval_adjoint(self):
return self
def _print_contents_latex(self, printer, *args):
if self.use_name:
return r'{\sigma_y^{(%s)}}' % str(self.name)
else:
return r'{\sigma_y}'
def _print_contents(self, printer, *args):
return 'SigmaY()'
def _eval_power(self, e):
if e.is_Integer and e.is_positive:
return SigmaY(self.name).__pow__(int(e) % 2)
def _represent_default_basis(self, **options):
format = options.get('format', 'sympy')
if format == 'sympy':
return Matrix([[0, -I], [I, 0]])
else:
raise NotImplementedError('Representation in format ' +
format + ' not implemented.')
class SigmaZ(SigmaOpBase):
"""Pauli sigma z operator
Parameters
==========
name : str
An optional string that labels the operator. Pauli operators with
different names commute.
Examples
========
>>> from sympy.physics.quantum import represent
>>> from sympy.physics.quantum.pauli import SigmaZ
>>> sz = SigmaZ()
>>> sz ** 3
SigmaZ()
>>> represent(sz)
Matrix([
[1, 0],
[0, -1]])
"""
def __new__(cls, *args, **hints):
return SigmaOpBase.__new__(cls, *args)
def _eval_commutator_SigmaX(self, other, **hints):
if self.name != other.name:
return S.Zero
else:
return 2 * I * SigmaY(self.name)
def _eval_commutator_SigmaY(self, other, **hints):
if self.name != other.name:
return S.Zero
else:
return - 2 * I * SigmaX(self.name)
def _eval_anticommutator_SigmaX(self, other, **hints):
return S.Zero
def _eval_anticommutator_SigmaY(self, other, **hints):
return S.Zero
def _eval_adjoint(self):
return self
def _print_contents_latex(self, printer, *args):
if self.use_name:
return r'{\sigma_z^{(%s)}}' % str(self.name)
else:
return r'{\sigma_z}'
def _print_contents(self, printer, *args):
return 'SigmaZ()'
def _eval_power(self, e):
if e.is_Integer and e.is_positive:
return SigmaZ(self.name).__pow__(int(e) % 2)
def _represent_default_basis(self, **options):
format = options.get('format', 'sympy')
if format == 'sympy':
return Matrix([[1, 0], [0, -1]])
else:
raise NotImplementedError('Representation in format ' +
format + ' not implemented.')
class SigmaMinus(SigmaOpBase):
"""Pauli sigma minus operator
Parameters
==========
name : str
An optional string that labels the operator. Pauli operators with
different names commute.
Examples
========
>>> from sympy.physics.quantum import represent, Dagger
>>> from sympy.physics.quantum.pauli import SigmaMinus
>>> sm = SigmaMinus()
>>> sm
SigmaMinus()
>>> Dagger(sm)
SigmaPlus()
>>> represent(sm)
Matrix([
[0, 0],
[1, 0]])
"""
def __new__(cls, *args, **hints):
return SigmaOpBase.__new__(cls, *args)
def _eval_commutator_SigmaX(self, other, **hints):
if self.name != other.name:
return S.Zero
else:
return -SigmaZ(self.name)
def _eval_commutator_SigmaY(self, other, **hints):
if self.name != other.name:
return S.Zero
else:
return I * SigmaZ(self.name)
def _eval_commutator_SigmaZ(self, other, **hints):
return 2 * self
def _eval_commutator_SigmaMinus(self, other, **hints):
return SigmaZ(self.name)
def _eval_anticommutator_SigmaZ(self, other, **hints):
return S.Zero
def _eval_anticommutator_SigmaX(self, other, **hints):
return S.One
def _eval_anticommutator_SigmaY(self, other, **hints):
return I * S.NegativeOne
def _eval_anticommutator_SigmaPlus(self, other, **hints):
return S.One
def _eval_adjoint(self):
return SigmaPlus(self.name)
def _eval_power(self, e):
if e.is_Integer and e.is_positive:
return S.Zero
def _print_contents_latex(self, printer, *args):
if self.use_name:
return r'{\sigma_-^{(%s)}}' % str(self.name)
else:
return r'{\sigma_-}'
def _print_contents(self, printer, *args):
return 'SigmaMinus()'
def _represent_default_basis(self, **options):
format = options.get('format', 'sympy')
if format == 'sympy':
return Matrix([[0, 0], [1, 0]])
else:
raise NotImplementedError('Representation in format ' +
format + ' not implemented.')
class SigmaPlus(SigmaOpBase):
"""Pauli sigma plus operator
Parameters
==========
name : str
An optional string that labels the operator. Pauli operators with
different names commute.
Examples
========
>>> from sympy.physics.quantum import represent, Dagger
>>> from sympy.physics.quantum.pauli import SigmaPlus
>>> sp = SigmaPlus()
>>> sp
SigmaPlus()
>>> Dagger(sp)
SigmaMinus()
>>> represent(sp)
Matrix([
[0, 1],
[0, 0]])
"""
def __new__(cls, *args, **hints):
return SigmaOpBase.__new__(cls, *args)
def _eval_commutator_SigmaX(self, other, **hints):
if self.name != other.name:
return S.Zero
else:
return SigmaZ(self.name)
def _eval_commutator_SigmaY(self, other, **hints):
if self.name != other.name:
return S.Zero
else:
return I * SigmaZ(self.name)
def _eval_commutator_SigmaZ(self, other, **hints):
if self.name != other.name:
return S.Zero
else:
return -2 * self
def _eval_commutator_SigmaMinus(self, other, **hints):
return SigmaZ(self.name)
def _eval_anticommutator_SigmaZ(self, other, **hints):
return S.Zero
def _eval_anticommutator_SigmaX(self, other, **hints):
return S.One
def _eval_anticommutator_SigmaY(self, other, **hints):
return I
def _eval_anticommutator_SigmaMinus(self, other, **hints):
return S.One
def _eval_adjoint(self):
return SigmaMinus(self.name)
def _eval_mul(self, other):
return self * other
def _eval_power(self, e):
if e.is_Integer and e.is_positive:
return S.Zero
def _print_contents_latex(self, printer, *args):
if self.use_name:
return r'{\sigma_+^{(%s)}}' % str(self.name)
else:
return r'{\sigma_+}'
def _print_contents(self, printer, *args):
return 'SigmaPlus()'
def _represent_default_basis(self, **options):
format = options.get('format', 'sympy')
if format == 'sympy':
return Matrix([[0, 1], [0, 0]])
else:
raise NotImplementedError('Representation in format ' +
format + ' not implemented.')
class SigmaZKet(Ket):
"""Ket for a two-level system quantum system.
Parameters
==========
n : Number
The state number (0 or 1).
"""
def __new__(cls, n):
if n not in (0, 1):
raise ValueError("n must be 0 or 1")
return Ket.__new__(cls, n)
@property
def n(self):
return self.label[0]
@classmethod
def dual_class(self):
return SigmaZBra
@classmethod
def _eval_hilbert_space(cls, label):
return ComplexSpace(2)
def _eval_innerproduct_SigmaZBra(self, bra, **hints):
return KroneckerDelta(self.n, bra.n)
def _apply_from_right_to_SigmaZ(self, op, **options):
if self.n == 0:
return self
else:
return S.NegativeOne * self
def _apply_from_right_to_SigmaX(self, op, **options):
return SigmaZKet(1) if self.n == 0 else SigmaZKet(0)
def _apply_from_right_to_SigmaY(self, op, **options):
return I * SigmaZKet(1) if self.n == 0 else (-I) * SigmaZKet(0)
def _apply_from_right_to_SigmaMinus(self, op, **options):
if self.n == 0:
return SigmaZKet(1)
else:
return S.Zero
def _apply_from_right_to_SigmaPlus(self, op, **options):
if self.n == 0:
return S.Zero
else:
return SigmaZKet(0)
def _represent_default_basis(self, **options):
format = options.get('format', 'sympy')
if format == 'sympy':
return Matrix([[1], [0]]) if self.n == 0 else Matrix([[0], [1]])
else:
raise NotImplementedError('Representation in format ' +
format + ' not implemented.')
class SigmaZBra(Bra):
"""Bra for a two-level quantum system.
Parameters
==========
n : Number
The state number (0 or 1).
"""
def __new__(cls, n):
if n not in (0, 1):
raise ValueError("n must be 0 or 1")
return Bra.__new__(cls, n)
@property
def n(self):
return self.label[0]
@classmethod
def dual_class(self):
return SigmaZKet
def _qsimplify_pauli_product(a, b):
"""
Internal helper function for simplifying products of Pauli operators.
"""
if not (isinstance(a, SigmaOpBase) and isinstance(b, SigmaOpBase)):
return Mul(a, b)
if a.name != b.name:
# Pauli matrices with different labels commute; sort by name
if a.name < b.name:
return Mul(a, b)
else:
return Mul(b, a)
elif isinstance(a, SigmaX):
if isinstance(b, SigmaX):
return S.One
if isinstance(b, SigmaY):
return I * SigmaZ(a.name)
if isinstance(b, SigmaZ):
return - I * SigmaY(a.name)
if isinstance(b, SigmaMinus):
return (S.Half + SigmaZ(a.name)/2)
if isinstance(b, SigmaPlus):
return (S.Half - SigmaZ(a.name)/2)
elif isinstance(a, SigmaY):
if isinstance(b, SigmaX):
return - I * SigmaZ(a.name)
if isinstance(b, SigmaY):
return S.One
if isinstance(b, SigmaZ):
return I * SigmaX(a.name)
if isinstance(b, SigmaMinus):
return -I * (S.One + SigmaZ(a.name))/2
if isinstance(b, SigmaPlus):
return I * (S.One - SigmaZ(a.name))/2
elif isinstance(a, SigmaZ):
if isinstance(b, SigmaX):
return I * SigmaY(a.name)
if isinstance(b, SigmaY):
return - I * SigmaX(a.name)
if isinstance(b, SigmaZ):
return S.One
if isinstance(b, SigmaMinus):
return - SigmaMinus(a.name)
if isinstance(b, SigmaPlus):
return SigmaPlus(a.name)
elif isinstance(a, SigmaMinus):
if isinstance(b, SigmaX):
return (S.One - SigmaZ(a.name))/2
if isinstance(b, SigmaY):
return - I * (S.One - SigmaZ(a.name))/2
if isinstance(b, SigmaZ):
# (SigmaX(a.name) - I * SigmaY(a.name))/2
return SigmaMinus(b.name)
if isinstance(b, SigmaMinus):
return S.Zero
if isinstance(b, SigmaPlus):
return S.Half - SigmaZ(a.name)/2
elif isinstance(a, SigmaPlus):
if isinstance(b, SigmaX):
return (S.One + SigmaZ(a.name))/2
if isinstance(b, SigmaY):
return I * (S.One + SigmaZ(a.name))/2
if isinstance(b, SigmaZ):
#-(SigmaX(a.name) + I * SigmaY(a.name))/2
return -SigmaPlus(a.name)
if isinstance(b, SigmaMinus):
return (S.One + SigmaZ(a.name))/2
if isinstance(b, SigmaPlus):
return S.Zero
else:
return a * b
def qsimplify_pauli(e):
"""
Simplify an expression that includes products of pauli operators.
Parameters
==========
e : expression
An expression that contains products of Pauli operators that is
to be simplified.
Examples
========
>>> from sympy.physics.quantum.pauli import SigmaX, SigmaY
>>> from sympy.physics.quantum.pauli import qsimplify_pauli
>>> sx, sy = SigmaX(), SigmaY()
>>> sx * sy
SigmaX()*SigmaY()
>>> qsimplify_pauli(sx * sy)
I*SigmaZ()
"""
if isinstance(e, Operator):
return e
if isinstance(e, (Add, Pow, exp)):
t = type(e)
return t(*(qsimplify_pauli(arg) for arg in e.args))
if isinstance(e, Mul):
c, nc = e.args_cnc()
nc_s = []
while nc:
curr = nc.pop(0)
while (len(nc) and
isinstance(curr, SigmaOpBase) and
isinstance(nc[0], SigmaOpBase) and
curr.name == nc[0].name):
x = nc.pop(0)
y = _qsimplify_pauli_product(curr, x)
c1, nc1 = y.args_cnc()
curr = Mul(*nc1)
c = c + c1
nc_s.append(curr)
return Mul(*c) * Mul(*nc_s)
return e
PK ]ZZZ� �<x x sympy/physics/quantum/piab.py"""1D quantum particle in a box."""
from sympy.core.numbers import pi
from sympy.core.singleton import S
from sympy.core.symbol import Symbol
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.elementary.trigonometric import sin
from sympy.sets.sets import Interval
from sympy.physics.quantum.operator import HermitianOperator
from sympy.physics.quantum.state import Ket, Bra
from sympy.physics.quantum.constants import hbar
from sympy.functions.special.tensor_functions import KroneckerDelta
from sympy.physics.quantum.hilbert import L2
m = Symbol('m')
L = Symbol('L')
__all__ = [
'PIABHamiltonian',
'PIABKet',
'PIABBra'
]
class PIABHamiltonian(HermitianOperator):
"""Particle in a box Hamiltonian operator."""
@classmethod
def _eval_hilbert_space(cls, label):
return L2(Interval(S.NegativeInfinity, S.Infinity))
def _apply_operator_PIABKet(self, ket, **options):
n = ket.label[0]
return (n**2*pi**2*hbar**2)/(2*m*L**2)*ket
class PIABKet(Ket):
"""Particle in a box eigenket."""
@classmethod
def _eval_hilbert_space(cls, args):
return L2(Interval(S.NegativeInfinity, S.Infinity))
@classmethod
def dual_class(self):
return PIABBra
def _represent_default_basis(self, **options):
return self._represent_XOp(None, **options)
def _represent_XOp(self, basis, **options):
x = Symbol('x')
n = Symbol('n')
subs_info = options.get('subs', {})
return sqrt(2/L)*sin(n*pi*x/L).subs(subs_info)
def _eval_innerproduct_PIABBra(self, bra):
return KroneckerDelta(bra.label[0], self.label[0])
class PIABBra(Bra):
"""Particle in a box eigenbra."""
@classmethod
def _eval_hilbert_space(cls, label):
return L2(Interval(S.NegativeInfinity, S.Infinity))
@classmethod
def dual_class(self):
return PIABKet
PK ]ZZZ���LR R sympy/physics/quantum/qapply.py"""Logic for applying operators to states.
Todo:
* Sometimes the final result needs to be expanded, we should do this by hand.
"""
from sympy.core.add import Add
from sympy.core.mul import Mul
from sympy.core.power import Pow
from sympy.core.singleton import S
from sympy.core.sympify import sympify
from sympy.physics.quantum.anticommutator import AntiCommutator
from sympy.physics.quantum.commutator import Commutator
from sympy.physics.quantum.dagger import Dagger
from sympy.physics.quantum.innerproduct import InnerProduct
from sympy.physics.quantum.operator import OuterProduct, Operator
from sympy.physics.quantum.state import State, KetBase, BraBase, Wavefunction
from sympy.physics.quantum.tensorproduct import TensorProduct
__all__ = [
'qapply'
]
#-----------------------------------------------------------------------------
# Main code
#-----------------------------------------------------------------------------
def qapply(e, **options):
"""Apply operators to states in a quantum expression.
Parameters
==========
e : Expr
The expression containing operators and states. This expression tree
will be walked to find operators acting on states symbolically.
options : dict
A dict of key/value pairs that determine how the operator actions
are carried out.
The following options are valid:
* ``dagger``: try to apply Dagger operators to the left
(default: False).
* ``ip_doit``: call ``.doit()`` in inner products when they are
encountered (default: True).
Returns
=======
e : Expr
The original expression, but with the operators applied to states.
Examples
========
>>> from sympy.physics.quantum import qapply, Ket, Bra
>>> b = Bra('b')
>>> k = Ket('k')
>>> A = k * b
>>> A
|k><b|
>>> qapply(A * b.dual / (b * b.dual))
|k>
>>> qapply(k.dual * A / (k.dual * k), dagger=True)
<b|
>>> qapply(k.dual * A / (k.dual * k))
<k|*|k><b|/<k|k>
"""
from sympy.physics.quantum.density import Density
dagger = options.get('dagger', False)
if e == 0:
return S.Zero
# This may be a bit aggressive but ensures that everything gets expanded
# to its simplest form before trying to apply operators. This includes
# things like (A+B+C)*|a> and A*(|a>+|b>) and all Commutators and
# TensorProducts. The only problem with this is that if we can't apply
# all the Operators, we have just expanded everything.
# TODO: don't expand the scalars in front of each Mul.
e = e.expand(commutator=True, tensorproduct=True)
# If we just have a raw ket, return it.
if isinstance(e, KetBase):
return e
# We have an Add(a, b, c, ...) and compute
# Add(qapply(a), qapply(b), ...)
elif isinstance(e, Add):
result = 0
for arg in e.args:
result += qapply(arg, **options)
return result.expand()
# For a Density operator call qapply on its state
elif isinstance(e, Density):
new_args = [(qapply(state, **options), prob) for (state,
prob) in e.args]
return Density(*new_args)
# For a raw TensorProduct, call qapply on its args.
elif isinstance(e, TensorProduct):
return TensorProduct(*[qapply(t, **options) for t in e.args])
# For a Pow, call qapply on its base.
elif isinstance(e, Pow):
return qapply(e.base, **options)**e.exp
# We have a Mul where there might be actual operators to apply to kets.
elif isinstance(e, Mul):
c_part, nc_part = e.args_cnc()
c_mul = Mul(*c_part)
nc_mul = Mul(*nc_part)
if isinstance(nc_mul, Mul):
result = c_mul*qapply_Mul(nc_mul, **options)
else:
result = c_mul*qapply(nc_mul, **options)
if result == e and dagger:
return Dagger(qapply_Mul(Dagger(e), **options))
else:
return result
# In all other cases (State, Operator, Pow, Commutator, InnerProduct,
# OuterProduct) we won't ever have operators to apply to kets.
else:
return e
def qapply_Mul(e, **options):
ip_doit = options.get('ip_doit', True)
args = list(e.args)
# If we only have 0 or 1 args, we have nothing to do and return.
if len(args) <= 1 or not isinstance(e, Mul):
return e
rhs = args.pop()
lhs = args.pop()
# Make sure we have two non-commutative objects before proceeding.
if (not isinstance(rhs, Wavefunction) and sympify(rhs).is_commutative) or \
(not isinstance(lhs, Wavefunction) and sympify(lhs).is_commutative):
return e
# For a Pow with an integer exponent, apply one of them and reduce the
# exponent by one.
if isinstance(lhs, Pow) and lhs.exp.is_Integer:
args.append(lhs.base**(lhs.exp - 1))
lhs = lhs.base
# Pull OuterProduct apart
if isinstance(lhs, OuterProduct):
args.append(lhs.ket)
lhs = lhs.bra
# Call .doit() on Commutator/AntiCommutator.
if isinstance(lhs, (Commutator, AntiCommutator)):
comm = lhs.doit()
if isinstance(comm, Add):
return qapply(
e.func(*(args + [comm.args[0], rhs])) +
e.func(*(args + [comm.args[1], rhs])),
**options
)
else:
return qapply(e.func(*args)*comm*rhs, **options)
# Apply tensor products of operators to states
if isinstance(lhs, TensorProduct) and all(isinstance(arg, (Operator, State, Mul, Pow)) or arg == 1 for arg in lhs.args) and \
isinstance(rhs, TensorProduct) and all(isinstance(arg, (Operator, State, Mul, Pow)) or arg == 1 for arg in rhs.args) and \
len(lhs.args) == len(rhs.args):
result = TensorProduct(*[qapply(lhs.args[n]*rhs.args[n], **options) for n in range(len(lhs.args))]).expand(tensorproduct=True)
return qapply_Mul(e.func(*args), **options)*result
# Now try to actually apply the operator and build an inner product.
try:
result = lhs._apply_operator(rhs, **options)
except NotImplementedError:
result = None
if result is None:
_apply_right = getattr(rhs, '_apply_from_right_to', None)
if _apply_right is not None:
try:
result = _apply_right(lhs, **options)
except NotImplementedError:
result = None
if result is None:
if isinstance(lhs, BraBase) and isinstance(rhs, KetBase):
result = InnerProduct(lhs, rhs)
if ip_doit:
result = result.doit()
# TODO: I may need to expand before returning the final result.
if result == 0:
return S.Zero
elif result is None:
if len(args) == 0:
# We had two args to begin with so args=[].
return e
else:
return qapply_Mul(e.func(*(args + [lhs])), **options)*rhs
elif isinstance(result, InnerProduct):
return result*qapply_Mul(e.func(*args), **options)
else: # result is a scalar times a Mul, Add or TensorProduct
return qapply(e.func(*args)*result, **options)
PK ]ZZZ��rؐ � sympy/physics/quantum/qasm.py"""
qasm.py - Functions to parse a set of qasm commands into a SymPy Circuit.
Examples taken from Chuang's page: https://web.archive.org/web/20220120121541/https://www.media.mit.edu/quanta/qasm2circ/
The code returns a circuit and an associated list of labels.
>>> from sympy.physics.quantum.qasm import Qasm
>>> q = Qasm('qubit q0', 'qubit q1', 'h q0', 'cnot q0,q1')
>>> q.get_circuit()
CNOT(1,0)*H(1)
>>> q = Qasm('qubit q0', 'qubit q1', 'cnot q0,q1', 'cnot q1,q0', 'cnot q0,q1')
>>> q.get_circuit()
CNOT(1,0)*CNOT(0,1)*CNOT(1,0)
"""
__all__ = [
'Qasm',
]
from math import prod
from sympy.physics.quantum.gate import H, CNOT, X, Z, CGate, CGateS, SWAP, S, T,CPHASE
from sympy.physics.quantum.circuitplot import Mz
def read_qasm(lines):
return Qasm(*lines.splitlines())
def read_qasm_file(filename):
return Qasm(*open(filename).readlines())
def flip_index(i, n):
"""Reorder qubit indices from largest to smallest.
>>> from sympy.physics.quantum.qasm import flip_index
>>> flip_index(0, 2)
1
>>> flip_index(1, 2)
0
"""
return n-i-1
def trim(line):
"""Remove everything following comment # characters in line.
>>> from sympy.physics.quantum.qasm import trim
>>> trim('nothing happens here')
'nothing happens here'
>>> trim('something #happens here')
'something '
"""
if '#' not in line:
return line
return line.split('#')[0]
def get_index(target, labels):
"""Get qubit labels from the rest of the line,and return indices
>>> from sympy.physics.quantum.qasm import get_index
>>> get_index('q0', ['q0', 'q1'])
1
>>> get_index('q1', ['q0', 'q1'])
0
"""
nq = len(labels)
return flip_index(labels.index(target), nq)
def get_indices(targets, labels):
return [get_index(t, labels) for t in targets]
def nonblank(args):
for line in args:
line = trim(line)
if line.isspace():
continue
yield line
return
def fullsplit(line):
words = line.split()
rest = ' '.join(words[1:])
return fixcommand(words[0]), [s.strip() for s in rest.split(',')]
def fixcommand(c):
"""Fix Qasm command names.
Remove all of forbidden characters from command c, and
replace 'def' with 'qdef'.
"""
forbidden_characters = ['-']
c = c.lower()
for char in forbidden_characters:
c = c.replace(char, '')
if c == 'def':
return 'qdef'
return c
def stripquotes(s):
"""Replace explicit quotes in a string.
>>> from sympy.physics.quantum.qasm import stripquotes
>>> stripquotes("'S'") == 'S'
True
>>> stripquotes('"S"') == 'S'
True
>>> stripquotes('S') == 'S'
True
"""
s = s.replace('"', '') # Remove second set of quotes?
s = s.replace("'", '')
return s
class Qasm:
"""Class to form objects from Qasm lines
>>> from sympy.physics.quantum.qasm import Qasm
>>> q = Qasm('qubit q0', 'qubit q1', 'h q0', 'cnot q0,q1')
>>> q.get_circuit()
CNOT(1,0)*H(1)
>>> q = Qasm('qubit q0', 'qubit q1', 'cnot q0,q1', 'cnot q1,q0', 'cnot q0,q1')
>>> q.get_circuit()
CNOT(1,0)*CNOT(0,1)*CNOT(1,0)
"""
def __init__(self, *args, **kwargs):
self.defs = {}
self.circuit = []
self.labels = []
self.inits = {}
self.add(*args)
self.kwargs = kwargs
def add(self, *lines):
for line in nonblank(lines):
command, rest = fullsplit(line)
if self.defs.get(command): #defs come first, since you can override built-in
function = self.defs.get(command)
indices = self.indices(rest)
if len(indices) == 1:
self.circuit.append(function(indices[0]))
else:
self.circuit.append(function(indices[:-1], indices[-1]))
elif hasattr(self, command):
function = getattr(self, command)
function(*rest)
else:
print("Function %s not defined. Skipping" % command)
def get_circuit(self):
return prod(reversed(self.circuit))
def get_labels(self):
return list(reversed(self.labels))
def plot(self):
from sympy.physics.quantum.circuitplot import CircuitPlot
circuit, labels = self.get_circuit(), self.get_labels()
CircuitPlot(circuit, len(labels), labels=labels, inits=self.inits)
def qubit(self, arg, init=None):
self.labels.append(arg)
if init: self.inits[arg] = init
def indices(self, args):
return get_indices(args, self.labels)
def index(self, arg):
return get_index(arg, self.labels)
def nop(self, *args):
pass
def x(self, arg):
self.circuit.append(X(self.index(arg)))
def z(self, arg):
self.circuit.append(Z(self.index(arg)))
def h(self, arg):
self.circuit.append(H(self.index(arg)))
def s(self, arg):
self.circuit.append(S(self.index(arg)))
def t(self, arg):
self.circuit.append(T(self.index(arg)))
def measure(self, arg):
self.circuit.append(Mz(self.index(arg)))
def cnot(self, a1, a2):
self.circuit.append(CNOT(*self.indices([a1, a2])))
def swap(self, a1, a2):
self.circuit.append(SWAP(*self.indices([a1, a2])))
def cphase(self, a1, a2):
self.circuit.append(CPHASE(*self.indices([a1, a2])))
def toffoli(self, a1, a2, a3):
i1, i2, i3 = self.indices([a1, a2, a3])
self.circuit.append(CGateS((i1, i2), X(i3)))
def cx(self, a1, a2):
fi, fj = self.indices([a1, a2])
self.circuit.append(CGate(fi, X(fj)))
def cz(self, a1, a2):
fi, fj = self.indices([a1, a2])
self.circuit.append(CGate(fi, Z(fj)))
def defbox(self, *args):
print("defbox not supported yet. Skipping: ", args)
def qdef(self, name, ncontrols, symbol):
from sympy.physics.quantum.circuitplot import CreateOneQubitGate, CreateCGate
ncontrols = int(ncontrols)
command = fixcommand(name)
symbol = stripquotes(symbol)
if ncontrols > 0:
self.defs[command] = CreateCGate(symbol)
else:
self.defs[command] = CreateOneQubitGate(symbol)
PK ]ZZZ#˫�6 �6 sympy/physics/quantum/qexpr.pyfrom sympy.core.expr import Expr
from sympy.core.symbol import Symbol
from sympy.core.sympify import sympify
from sympy.matrices.dense import Matrix
from sympy.printing.pretty.stringpict import prettyForm
from sympy.core.containers import Tuple
from sympy.utilities.iterables import is_sequence
from sympy.physics.quantum.dagger import Dagger
from sympy.physics.quantum.matrixutils import (
numpy_ndarray, scipy_sparse_matrix,
to_sympy, to_numpy, to_scipy_sparse
)
__all__ = [
'QuantumError',
'QExpr'
]
#-----------------------------------------------------------------------------
# Error handling
#-----------------------------------------------------------------------------
class QuantumError(Exception):
pass
def _qsympify_sequence(seq):
"""Convert elements of a sequence to standard form.
This is like sympify, but it performs special logic for arguments passed
to QExpr. The following conversions are done:
* (list, tuple, Tuple) => _qsympify_sequence each element and convert
sequence to a Tuple.
* basestring => Symbol
* Matrix => Matrix
* other => sympify
Strings are passed to Symbol, not sympify to make sure that variables like
'pi' are kept as Symbols, not the SymPy built-in number subclasses.
Examples
========
>>> from sympy.physics.quantum.qexpr import _qsympify_sequence
>>> _qsympify_sequence((1,2,[3,4,[1,]]))
(1, 2, (3, 4, (1,)))
"""
return tuple(__qsympify_sequence_helper(seq))
def __qsympify_sequence_helper(seq):
"""
Helper function for _qsympify_sequence
This function does the actual work.
"""
#base case. If not a list, do Sympification
if not is_sequence(seq):
if isinstance(seq, Matrix):
return seq
elif isinstance(seq, str):
return Symbol(seq)
else:
return sympify(seq)
# base condition, when seq is QExpr and also
# is iterable.
if isinstance(seq, QExpr):
return seq
#if list, recurse on each item in the list
result = [__qsympify_sequence_helper(item) for item in seq]
return Tuple(*result)
#-----------------------------------------------------------------------------
# Basic Quantum Expression from which all objects descend
#-----------------------------------------------------------------------------
class QExpr(Expr):
"""A base class for all quantum object like operators and states."""
# In sympy, slots are for instance attributes that are computed
# dynamically by the __new__ method. They are not part of args, but they
# derive from args.
# The Hilbert space a quantum Object belongs to.
__slots__ = ('hilbert_space', )
is_commutative = False
# The separator used in printing the label.
_label_separator = ''
@property
def free_symbols(self):
return {self}
def __new__(cls, *args, **kwargs):
"""Construct a new quantum object.
Parameters
==========
args : tuple
The list of numbers or parameters that uniquely specify the
quantum object. For a state, this will be its symbol or its
set of quantum numbers.
Examples
========
>>> from sympy.physics.quantum.qexpr import QExpr
>>> q = QExpr(0)
>>> q
0
>>> q.label
(0,)
>>> q.hilbert_space
H
>>> q.args
(0,)
>>> q.is_commutative
False
"""
# First compute args and call Expr.__new__ to create the instance
args = cls._eval_args(args, **kwargs)
if len(args) == 0:
args = cls._eval_args(tuple(cls.default_args()), **kwargs)
inst = Expr.__new__(cls, *args)
# Now set the slots on the instance
inst.hilbert_space = cls._eval_hilbert_space(args)
return inst
@classmethod
def _new_rawargs(cls, hilbert_space, *args, **old_assumptions):
"""Create new instance of this class with hilbert_space and args.
This is used to bypass the more complex logic in the ``__new__``
method in cases where you already have the exact ``hilbert_space``
and ``args``. This should be used when you are positive these
arguments are valid, in their final, proper form and want to optimize
the creation of the object.
"""
obj = Expr.__new__(cls, *args, **old_assumptions)
obj.hilbert_space = hilbert_space
return obj
#-------------------------------------------------------------------------
# Properties
#-------------------------------------------------------------------------
@property
def label(self):
"""The label is the unique set of identifiers for the object.
Usually, this will include all of the information about the state
*except* the time (in the case of time-dependent objects).
This must be a tuple, rather than a Tuple.
"""
if len(self.args) == 0: # If there is no label specified, return the default
return self._eval_args(list(self.default_args()))
else:
return self.args
@property
def is_symbolic(self):
return True
@classmethod
def default_args(self):
"""If no arguments are specified, then this will return a default set
of arguments to be run through the constructor.
NOTE: Any classes that override this MUST return a tuple of arguments.
Should be overridden by subclasses to specify the default arguments for kets and operators
"""
raise NotImplementedError("No default arguments for this class!")
#-------------------------------------------------------------------------
# _eval_* methods
#-------------------------------------------------------------------------
def _eval_adjoint(self):
obj = Expr._eval_adjoint(self)
if obj is None:
obj = Expr.__new__(Dagger, self)
if isinstance(obj, QExpr):
obj.hilbert_space = self.hilbert_space
return obj
@classmethod
def _eval_args(cls, args):
"""Process the args passed to the __new__ method.
This simply runs args through _qsympify_sequence.
"""
return _qsympify_sequence(args)
@classmethod
def _eval_hilbert_space(cls, args):
"""Compute the Hilbert space instance from the args.
"""
from sympy.physics.quantum.hilbert import HilbertSpace
return HilbertSpace()
#-------------------------------------------------------------------------
# Printing
#-------------------------------------------------------------------------
# Utilities for printing: these operate on raw SymPy objects
def _print_sequence(self, seq, sep, printer, *args):
result = []
for item in seq:
result.append(printer._print(item, *args))
return sep.join(result)
def _print_sequence_pretty(self, seq, sep, printer, *args):
pform = printer._print(seq[0], *args)
for item in seq[1:]:
pform = prettyForm(*pform.right(sep))
pform = prettyForm(*pform.right(printer._print(item, *args)))
return pform
# Utilities for printing: these operate prettyForm objects
def _print_subscript_pretty(self, a, b):
top = prettyForm(*b.left(' '*a.width()))
bot = prettyForm(*a.right(' '*b.width()))
return prettyForm(binding=prettyForm.POW, *bot.below(top))
def _print_superscript_pretty(self, a, b):
return a**b
def _print_parens_pretty(self, pform, left='(', right=')'):
return prettyForm(*pform.parens(left=left, right=right))
# Printing of labels (i.e. args)
def _print_label(self, printer, *args):
"""Prints the label of the QExpr
This method prints self.label, using self._label_separator to separate
the elements. This method should not be overridden, instead, override
_print_contents to change printing behavior.
"""
return self._print_sequence(
self.label, self._label_separator, printer, *args
)
def _print_label_repr(self, printer, *args):
return self._print_sequence(
self.label, ',', printer, *args
)
def _print_label_pretty(self, printer, *args):
return self._print_sequence_pretty(
self.label, self._label_separator, printer, *args
)
def _print_label_latex(self, printer, *args):
return self._print_sequence(
self.label, self._label_separator, printer, *args
)
# Printing of contents (default to label)
def _print_contents(self, printer, *args):
"""Printer for contents of QExpr
Handles the printing of any unique identifying contents of a QExpr to
print as its contents, such as any variables or quantum numbers. The
default is to print the label, which is almost always the args. This
should not include printing of any brackets or parentheses.
"""
return self._print_label(printer, *args)
def _print_contents_pretty(self, printer, *args):
return self._print_label_pretty(printer, *args)
def _print_contents_latex(self, printer, *args):
return self._print_label_latex(printer, *args)
# Main printing methods
def _sympystr(self, printer, *args):
"""Default printing behavior of QExpr objects
Handles the default printing of a QExpr. To add other things to the
printing of the object, such as an operator name to operators or
brackets to states, the class should override the _print/_pretty/_latex
functions directly and make calls to _print_contents where appropriate.
This allows things like InnerProduct to easily control its printing the
printing of contents.
"""
return self._print_contents(printer, *args)
def _sympyrepr(self, printer, *args):
classname = self.__class__.__name__
label = self._print_label_repr(printer, *args)
return '%s(%s)' % (classname, label)
def _pretty(self, printer, *args):
pform = self._print_contents_pretty(printer, *args)
return pform
def _latex(self, printer, *args):
return self._print_contents_latex(printer, *args)
#-------------------------------------------------------------------------
# Represent
#-------------------------------------------------------------------------
def _represent_default_basis(self, **options):
raise NotImplementedError('This object does not have a default basis')
def _represent(self, *, basis=None, **options):
"""Represent this object in a given basis.
This method dispatches to the actual methods that perform the
representation. Subclases of QExpr should define various methods to
determine how the object will be represented in various bases. The
format of these methods is::
def _represent_BasisName(self, basis, **options):
Thus to define how a quantum object is represented in the basis of
the operator Position, you would define::
def _represent_Position(self, basis, **options):
Usually, basis object will be instances of Operator subclasses, but
there is a chance we will relax this in the future to accommodate other
types of basis sets that are not associated with an operator.
If the ``format`` option is given it can be ("sympy", "numpy",
"scipy.sparse"). This will ensure that any matrices that result from
representing the object are returned in the appropriate matrix format.
Parameters
==========
basis : Operator
The Operator whose basis functions will be used as the basis for
representation.
options : dict
A dictionary of key/value pairs that give options and hints for
the representation, such as the number of basis functions to
be used.
"""
if basis is None:
result = self._represent_default_basis(**options)
else:
result = dispatch_method(self, '_represent', basis, **options)
# If we get a matrix representation, convert it to the right format.
format = options.get('format', 'sympy')
result = self._format_represent(result, format)
return result
def _format_represent(self, result, format):
if format == 'sympy' and not isinstance(result, Matrix):
return to_sympy(result)
elif format == 'numpy' and not isinstance(result, numpy_ndarray):
return to_numpy(result)
elif format == 'scipy.sparse' and \
not isinstance(result, scipy_sparse_matrix):
return to_scipy_sparse(result)
return result
def split_commutative_parts(e):
"""Split into commutative and non-commutative parts."""
c_part, nc_part = e.args_cnc()
c_part = list(c_part)
return c_part, nc_part
def split_qexpr_parts(e):
"""Split an expression into Expr and noncommutative QExpr parts."""
expr_part = []
qexpr_part = []
for arg in e.args:
if not isinstance(arg, QExpr):
expr_part.append(arg)
else:
qexpr_part.append(arg)
return expr_part, qexpr_part
def dispatch_method(self, basename, arg, **options):
"""Dispatch a method to the proper handlers."""
method_name = '%s_%s' % (basename, arg.__class__.__name__)
if hasattr(self, method_name):
f = getattr(self, method_name)
# This can raise and we will allow it to propagate.
result = f(arg, **options)
if result is not None:
return result
raise NotImplementedError(
"%s.%s cannot handle: %r" %
(self.__class__.__name__, basename, arg)
)
PK ]ZZZ�1'� sympy/physics/quantum/qft.py"""An implementation of qubits and gates acting on them.
Todo:
* Update docstrings.
* Update tests.
* Implement apply using decompose.
* Implement represent using decompose or something smarter. For this to
work we first have to implement represent for SWAP.
* Decide if we want upper index to be inclusive in the constructor.
* Fix the printing of Rk gates in plotting.
"""
from sympy.core.expr import Expr
from sympy.core.numbers import (I, Integer, pi)
from sympy.core.symbol import Symbol
from sympy.functions.elementary.exponential import exp
from sympy.matrices.dense import Matrix
from sympy.functions import sqrt
from sympy.physics.quantum.qapply import qapply
from sympy.physics.quantum.qexpr import QuantumError, QExpr
from sympy.matrices import eye
from sympy.physics.quantum.tensorproduct import matrix_tensor_product
from sympy.physics.quantum.gate import (
Gate, HadamardGate, SwapGate, OneQubitGate, CGate, PhaseGate, TGate, ZGate
)
from sympy.functions.elementary.complexes import sign
__all__ = [
'QFT',
'IQFT',
'RkGate',
'Rk'
]
#-----------------------------------------------------------------------------
# Fourier stuff
#-----------------------------------------------------------------------------
class RkGate(OneQubitGate):
"""This is the R_k gate of the QTF."""
gate_name = 'Rk'
gate_name_latex = 'R'
def __new__(cls, *args):
if len(args) != 2:
raise QuantumError(
'Rk gates only take two arguments, got: %r' % args
)
# For small k, Rk gates simplify to other gates, using these
# substitutions give us familiar results for the QFT for small numbers
# of qubits.
target = args[0]
k = args[1]
if k == 1:
return ZGate(target)
elif k == 2:
return PhaseGate(target)
elif k == 3:
return TGate(target)
args = cls._eval_args(args)
inst = Expr.__new__(cls, *args)
inst.hilbert_space = cls._eval_hilbert_space(args)
return inst
@classmethod
def _eval_args(cls, args):
# Fall back to this, because Gate._eval_args assumes that args is
# all targets and can't contain duplicates.
return QExpr._eval_args(args)
@property
def k(self):
return self.label[1]
@property
def targets(self):
return self.label[:1]
@property
def gate_name_plot(self):
return r'$%s_%s$' % (self.gate_name_latex, str(self.k))
def get_target_matrix(self, format='sympy'):
if format == 'sympy':
return Matrix([[1, 0], [0, exp(sign(self.k)*Integer(2)*pi*I/(Integer(2)**abs(self.k)))]])
raise NotImplementedError(
'Invalid format for the R_k gate: %r' % format)
Rk = RkGate
class Fourier(Gate):
"""Superclass of Quantum Fourier and Inverse Quantum Fourier Gates."""
@classmethod
def _eval_args(self, args):
if len(args) != 2:
raise QuantumError(
'QFT/IQFT only takes two arguments, got: %r' % args
)
if args[0] >= args[1]:
raise QuantumError("Start must be smaller than finish")
return Gate._eval_args(args)
def _represent_default_basis(self, **options):
return self._represent_ZGate(None, **options)
def _represent_ZGate(self, basis, **options):
"""
Represents the (I)QFT In the Z Basis
"""
nqubits = options.get('nqubits', 0)
if nqubits == 0:
raise QuantumError(
'The number of qubits must be given as nqubits.')
if nqubits < self.min_qubits:
raise QuantumError(
'The number of qubits %r is too small for the gate.' % nqubits
)
size = self.size
omega = self.omega
#Make a matrix that has the basic Fourier Transform Matrix
arrayFT = [[omega**(
i*j % size)/sqrt(size) for i in range(size)] for j in range(size)]
matrixFT = Matrix(arrayFT)
#Embed the FT Matrix in a higher space, if necessary
if self.label[0] != 0:
matrixFT = matrix_tensor_product(eye(2**self.label[0]), matrixFT)
if self.min_qubits < nqubits:
matrixFT = matrix_tensor_product(
matrixFT, eye(2**(nqubits - self.min_qubits)))
return matrixFT
@property
def targets(self):
return range(self.label[0], self.label[1])
@property
def min_qubits(self):
return self.label[1]
@property
def size(self):
"""Size is the size of the QFT matrix"""
return 2**(self.label[1] - self.label[0])
@property
def omega(self):
return Symbol('omega')
class QFT(Fourier):
"""The forward quantum Fourier transform."""
gate_name = 'QFT'
gate_name_latex = 'QFT'
def decompose(self):
"""Decomposes QFT into elementary gates."""
start = self.label[0]
finish = self.label[1]
circuit = 1
for level in reversed(range(start, finish)):
circuit = HadamardGate(level)*circuit
for i in range(level - start):
circuit = CGate(level - i - 1, RkGate(level, i + 2))*circuit
for i in range((finish - start)//2):
circuit = SwapGate(i + start, finish - i - 1)*circuit
return circuit
def _apply_operator_Qubit(self, qubits, **options):
return qapply(self.decompose()*qubits)
def _eval_inverse(self):
return IQFT(*self.args)
@property
def omega(self):
return exp(2*pi*I/self.size)
class IQFT(Fourier):
"""The inverse quantum Fourier transform."""
gate_name = 'IQFT'
gate_name_latex = '{QFT^{-1}}'
def decompose(self):
"""Decomposes IQFT into elementary gates."""
start = self.args[0]
finish = self.args[1]
circuit = 1
for i in range((finish - start)//2):
circuit = SwapGate(i + start, finish - i - 1)*circuit
for level in range(start, finish):
for i in reversed(range(level - start)):
circuit = CGate(level - i - 1, RkGate(level, -i - 2))*circuit
circuit = HadamardGate(level)*circuit
return circuit
def _eval_inverse(self):
return QFT(*self.args)
@property
def omega(self):
return exp(-2*pi*I/self.size)
PK ]ZZZ�R^�e �e sympy/physics/quantum/qubit.py"""Qubits for quantum computing.
Todo:
* Finish implementing measurement logic. This should include POVM.
* Update docstrings.
* Update tests.
"""
import math
from sympy.core.add import Add
from sympy.core.mul import Mul
from sympy.core.numbers import Integer
from sympy.core.power import Pow
from sympy.core.singleton import S
from sympy.functions.elementary.complexes import conjugate
from sympy.functions.elementary.exponential import log
from sympy.core.basic import _sympify
from sympy.external.gmpy import SYMPY_INTS
from sympy.matrices import Matrix, zeros
from sympy.printing.pretty.stringpict import prettyForm
from sympy.physics.quantum.hilbert import ComplexSpace
from sympy.physics.quantum.state import Ket, Bra, State
from sympy.physics.quantum.qexpr import QuantumError
from sympy.physics.quantum.represent import represent
from sympy.physics.quantum.matrixutils import (
numpy_ndarray, scipy_sparse_matrix
)
from mpmath.libmp.libintmath import bitcount
__all__ = [
'Qubit',
'QubitBra',
'IntQubit',
'IntQubitBra',
'qubit_to_matrix',
'matrix_to_qubit',
'matrix_to_density',
'measure_all',
'measure_partial',
'measure_partial_oneshot',
'measure_all_oneshot'
]
#-----------------------------------------------------------------------------
# Qubit Classes
#-----------------------------------------------------------------------------
class QubitState(State):
"""Base class for Qubit and QubitBra."""
#-------------------------------------------------------------------------
# Initialization/creation
#-------------------------------------------------------------------------
@classmethod
def _eval_args(cls, args):
# If we are passed a QubitState or subclass, we just take its qubit
# values directly.
if len(args) == 1 and isinstance(args[0], QubitState):
return args[0].qubit_values
# Turn strings into tuple of strings
if len(args) == 1 and isinstance(args[0], str):
args = tuple( S.Zero if qb == "0" else S.One for qb in args[0])
else:
args = tuple( S.Zero if qb == "0" else S.One if qb == "1" else qb for qb in args)
args = tuple(_sympify(arg) for arg in args)
# Validate input (must have 0 or 1 input)
for element in args:
if element not in (S.Zero, S.One):
raise ValueError(
"Qubit values must be 0 or 1, got: %r" % element)
return args
@classmethod
def _eval_hilbert_space(cls, args):
return ComplexSpace(2)**len(args)
#-------------------------------------------------------------------------
# Properties
#-------------------------------------------------------------------------
@property
def dimension(self):
"""The number of Qubits in the state."""
return len(self.qubit_values)
@property
def nqubits(self):
return self.dimension
@property
def qubit_values(self):
"""Returns the values of the qubits as a tuple."""
return self.label
#-------------------------------------------------------------------------
# Special methods
#-------------------------------------------------------------------------
def __len__(self):
return self.dimension
def __getitem__(self, bit):
return self.qubit_values[int(self.dimension - bit - 1)]
#-------------------------------------------------------------------------
# Utility methods
#-------------------------------------------------------------------------
def flip(self, *bits):
"""Flip the bit(s) given."""
newargs = list(self.qubit_values)
for i in bits:
bit = int(self.dimension - i - 1)
if newargs[bit] == 1:
newargs[bit] = 0
else:
newargs[bit] = 1
return self.__class__(*tuple(newargs))
class Qubit(QubitState, Ket):
"""A multi-qubit ket in the computational (z) basis.
We use the normal convention that the least significant qubit is on the
right, so ``|00001>`` has a 1 in the least significant qubit.
Parameters
==========
values : list, str
The qubit values as a list of ints ([0,0,0,1,1,]) or a string ('011').
Examples
========
Create a qubit in a couple of different ways and look at their attributes:
>>> from sympy.physics.quantum.qubit import Qubit
>>> Qubit(0,0,0)
|000>
>>> q = Qubit('0101')
>>> q
|0101>
>>> q.nqubits
4
>>> len(q)
4
>>> q.dimension
4
>>> q.qubit_values
(0, 1, 0, 1)
We can flip the value of an individual qubit:
>>> q.flip(1)
|0111>
We can take the dagger of a Qubit to get a bra:
>>> from sympy.physics.quantum.dagger import Dagger
>>> Dagger(q)
<0101|
>>> type(Dagger(q))
<class 'sympy.physics.quantum.qubit.QubitBra'>
Inner products work as expected:
>>> ip = Dagger(q)*q
>>> ip
<0101|0101>
>>> ip.doit()
1
"""
@classmethod
def dual_class(self):
return QubitBra
def _eval_innerproduct_QubitBra(self, bra, **hints):
if self.label == bra.label:
return S.One
else:
return S.Zero
def _represent_default_basis(self, **options):
return self._represent_ZGate(None, **options)
def _represent_ZGate(self, basis, **options):
"""Represent this qubits in the computational basis (ZGate).
"""
_format = options.get('format', 'sympy')
n = 1
definite_state = 0
for it in reversed(self.qubit_values):
definite_state += n*it
n = n*2
result = [0]*(2**self.dimension)
result[int(definite_state)] = 1
if _format == 'sympy':
return Matrix(result)
elif _format == 'numpy':
import numpy as np
return np.array(result, dtype='complex').transpose()
elif _format == 'scipy.sparse':
from scipy import sparse
return sparse.csr_matrix(result, dtype='complex').transpose()
def _eval_trace(self, bra, **kwargs):
indices = kwargs.get('indices', [])
#sort index list to begin trace from most-significant
#qubit
sorted_idx = list(indices)
if len(sorted_idx) == 0:
sorted_idx = list(range(0, self.nqubits))
sorted_idx.sort()
#trace out for each of index
new_mat = self*bra
for i in range(len(sorted_idx) - 1, -1, -1):
# start from tracing out from leftmost qubit
new_mat = self._reduced_density(new_mat, int(sorted_idx[i]))
if (len(sorted_idx) == self.nqubits):
#in case full trace was requested
return new_mat[0]
else:
return matrix_to_density(new_mat)
def _reduced_density(self, matrix, qubit, **options):
"""Compute the reduced density matrix by tracing out one qubit.
The qubit argument should be of type Python int, since it is used
in bit operations
"""
def find_index_that_is_projected(j, k, qubit):
bit_mask = 2**qubit - 1
return ((j >> qubit) << (1 + qubit)) + (j & bit_mask) + (k << qubit)
old_matrix = represent(matrix, **options)
old_size = old_matrix.cols
#we expect the old_size to be even
new_size = old_size//2
new_matrix = Matrix().zeros(new_size)
for i in range(new_size):
for j in range(new_size):
for k in range(2):
col = find_index_that_is_projected(j, k, qubit)
row = find_index_that_is_projected(i, k, qubit)
new_matrix[i, j] += old_matrix[row, col]
return new_matrix
class QubitBra(QubitState, Bra):
"""A multi-qubit bra in the computational (z) basis.
We use the normal convention that the least significant qubit is on the
right, so ``|00001>`` has a 1 in the least significant qubit.
Parameters
==========
values : list, str
The qubit values as a list of ints ([0,0,0,1,1,]) or a string ('011').
See also
========
Qubit: Examples using qubits
"""
@classmethod
def dual_class(self):
return Qubit
class IntQubitState(QubitState):
"""A base class for qubits that work with binary representations."""
@classmethod
def _eval_args(cls, args, nqubits=None):
# The case of a QubitState instance
if len(args) == 1 and isinstance(args[0], QubitState):
return QubitState._eval_args(args)
# otherwise, args should be integer
elif not all(isinstance(a, (int, Integer)) for a in args):
raise ValueError('values must be integers, got (%s)' % (tuple(type(a) for a in args),))
# use nqubits if specified
if nqubits is not None:
if not isinstance(nqubits, (int, Integer)):
raise ValueError('nqubits must be an integer, got (%s)' % type(nqubits))
if len(args) != 1:
raise ValueError(
'too many positional arguments (%s). should be (number, nqubits=n)' % (args,))
return cls._eval_args_with_nqubits(args[0], nqubits)
# For a single argument, we construct the binary representation of
# that integer with the minimal number of bits.
if len(args) == 1 and args[0] > 1:
#rvalues is the minimum number of bits needed to express the number
rvalues = reversed(range(bitcount(abs(args[0]))))
qubit_values = [(args[0] >> i) & 1 for i in rvalues]
return QubitState._eval_args(qubit_values)
# For two numbers, the second number is the number of bits
# on which it is expressed, so IntQubit(0,5) == |00000>.
elif len(args) == 2 and args[1] > 1:
return cls._eval_args_with_nqubits(args[0], args[1])
else:
return QubitState._eval_args(args)
@classmethod
def _eval_args_with_nqubits(cls, number, nqubits):
need = bitcount(abs(number))
if nqubits < need:
raise ValueError(
'cannot represent %s with %s bits' % (number, nqubits))
qubit_values = [(number >> i) & 1 for i in reversed(range(nqubits))]
return QubitState._eval_args(qubit_values)
def as_int(self):
"""Return the numerical value of the qubit."""
number = 0
n = 1
for i in reversed(self.qubit_values):
number += n*i
n = n << 1
return number
def _print_label(self, printer, *args):
return str(self.as_int())
def _print_label_pretty(self, printer, *args):
label = self._print_label(printer, *args)
return prettyForm(label)
_print_label_repr = _print_label
_print_label_latex = _print_label
class IntQubit(IntQubitState, Qubit):
"""A qubit ket that store integers as binary numbers in qubit values.
The differences between this class and ``Qubit`` are:
* The form of the constructor.
* The qubit values are printed as their corresponding integer, rather
than the raw qubit values. The internal storage format of the qubit
values in the same as ``Qubit``.
Parameters
==========
values : int, tuple
If a single argument, the integer we want to represent in the qubit
values. This integer will be represented using the fewest possible
number of qubits.
If a pair of integers and the second value is more than one, the first
integer gives the integer to represent in binary form and the second
integer gives the number of qubits to use.
List of zeros and ones is also accepted to generate qubit by bit pattern.
nqubits : int
The integer that represents the number of qubits.
This number should be passed with keyword ``nqubits=N``.
You can use this in order to avoid ambiguity of Qubit-style tuple of bits.
Please see the example below for more details.
Examples
========
Create a qubit for the integer 5:
>>> from sympy.physics.quantum.qubit import IntQubit
>>> from sympy.physics.quantum.qubit import Qubit
>>> q = IntQubit(5)
>>> q
|5>
We can also create an ``IntQubit`` by passing a ``Qubit`` instance.
>>> q = IntQubit(Qubit('101'))
>>> q
|5>
>>> q.as_int()
5
>>> q.nqubits
3
>>> q.qubit_values
(1, 0, 1)
We can go back to the regular qubit form.
>>> Qubit(q)
|101>
Please note that ``IntQubit`` also accepts a ``Qubit``-style list of bits.
So, the code below yields qubits 3, not a single bit ``1``.
>>> IntQubit(1, 1)
|3>
To avoid ambiguity, use ``nqubits`` parameter.
Use of this keyword is recommended especially when you provide the values by variables.
>>> IntQubit(1, nqubits=1)
|1>
>>> a = 1
>>> IntQubit(a, nqubits=1)
|1>
"""
@classmethod
def dual_class(self):
return IntQubitBra
def _eval_innerproduct_IntQubitBra(self, bra, **hints):
return Qubit._eval_innerproduct_QubitBra(self, bra)
class IntQubitBra(IntQubitState, QubitBra):
"""A qubit bra that store integers as binary numbers in qubit values."""
@classmethod
def dual_class(self):
return IntQubit
#-----------------------------------------------------------------------------
# Qubit <---> Matrix conversion functions
#-----------------------------------------------------------------------------
def matrix_to_qubit(matrix):
"""Convert from the matrix repr. to a sum of Qubit objects.
Parameters
----------
matrix : Matrix, numpy.matrix, scipy.sparse
The matrix to build the Qubit representation of. This works with
SymPy matrices, numpy matrices and scipy.sparse sparse matrices.
Examples
========
Represent a state and then go back to its qubit form:
>>> from sympy.physics.quantum.qubit import matrix_to_qubit, Qubit
>>> from sympy.physics.quantum.represent import represent
>>> q = Qubit('01')
>>> matrix_to_qubit(represent(q))
|01>
"""
# Determine the format based on the type of the input matrix
format = 'sympy'
if isinstance(matrix, numpy_ndarray):
format = 'numpy'
if isinstance(matrix, scipy_sparse_matrix):
format = 'scipy.sparse'
# Make sure it is of correct dimensions for a Qubit-matrix representation.
# This logic should work with sympy, numpy or scipy.sparse matrices.
if matrix.shape[0] == 1:
mlistlen = matrix.shape[1]
nqubits = log(mlistlen, 2)
ket = False
cls = QubitBra
elif matrix.shape[1] == 1:
mlistlen = matrix.shape[0]
nqubits = log(mlistlen, 2)
ket = True
cls = Qubit
else:
raise QuantumError(
'Matrix must be a row/column vector, got %r' % matrix
)
if not isinstance(nqubits, Integer):
raise QuantumError('Matrix must be a row/column vector of size '
'2**nqubits, got: %r' % matrix)
# Go through each item in matrix, if element is non-zero, make it into a
# Qubit item times the element.
result = 0
for i in range(mlistlen):
if ket:
element = matrix[i, 0]
else:
element = matrix[0, i]
if format in ('numpy', 'scipy.sparse'):
element = complex(element)
if element:
# Form Qubit array; 0 in bit-locations where i is 0, 1 in
# bit-locations where i is 1
qubit_array = [int(i & (1 << x) != 0) for x in range(nqubits)]
qubit_array.reverse()
result = result + element*cls(*qubit_array)
# If SymPy simplified by pulling out a constant coefficient, undo that.
if isinstance(result, (Mul, Add, Pow)):
result = result.expand()
return result
def matrix_to_density(mat):
"""
Works by finding the eigenvectors and eigenvalues of the matrix.
We know we can decompose rho by doing:
sum(EigenVal*|Eigenvect><Eigenvect|)
"""
from sympy.physics.quantum.density import Density
eigen = mat.eigenvects()
args = [[matrix_to_qubit(Matrix(
[vector, ])), x[0]] for x in eigen for vector in x[2] if x[0] != 0]
if (len(args) == 0):
return S.Zero
else:
return Density(*args)
def qubit_to_matrix(qubit, format='sympy'):
"""Converts an Add/Mul of Qubit objects into it's matrix representation
This function is the inverse of ``matrix_to_qubit`` and is a shorthand
for ``represent(qubit)``.
"""
return represent(qubit, format=format)
#-----------------------------------------------------------------------------
# Measurement
#-----------------------------------------------------------------------------
def measure_all(qubit, format='sympy', normalize=True):
"""Perform an ensemble measurement of all qubits.
Parameters
==========
qubit : Qubit, Add
The qubit to measure. This can be any Qubit or a linear combination
of them.
format : str
The format of the intermediate matrices to use. Possible values are
('sympy','numpy','scipy.sparse'). Currently only 'sympy' is
implemented.
Returns
=======
result : list
A list that consists of primitive states and their probabilities.
Examples
========
>>> from sympy.physics.quantum.qubit import Qubit, measure_all
>>> from sympy.physics.quantum.gate import H
>>> from sympy.physics.quantum.qapply import qapply
>>> c = H(0)*H(1)*Qubit('00')
>>> c
H(0)*H(1)*|00>
>>> q = qapply(c)
>>> measure_all(q)
[(|00>, 1/4), (|01>, 1/4), (|10>, 1/4), (|11>, 1/4)]
"""
m = qubit_to_matrix(qubit, format)
if format == 'sympy':
results = []
if normalize:
m = m.normalized()
size = max(m.shape) # Max of shape to account for bra or ket
nqubits = int(math.log(size)/math.log(2))
for i in range(size):
if m[i]:
results.append(
(Qubit(IntQubit(i, nqubits=nqubits)), m[i]*conjugate(m[i]))
)
return results
else:
raise NotImplementedError(
"This function cannot handle non-SymPy matrix formats yet"
)
def measure_partial(qubit, bits, format='sympy', normalize=True):
"""Perform a partial ensemble measure on the specified qubits.
Parameters
==========
qubits : Qubit
The qubit to measure. This can be any Qubit or a linear combination
of them.
bits : tuple
The qubits to measure.
format : str
The format of the intermediate matrices to use. Possible values are
('sympy','numpy','scipy.sparse'). Currently only 'sympy' is
implemented.
Returns
=======
result : list
A list that consists of primitive states and their probabilities.
Examples
========
>>> from sympy.physics.quantum.qubit import Qubit, measure_partial
>>> from sympy.physics.quantum.gate import H
>>> from sympy.physics.quantum.qapply import qapply
>>> c = H(0)*H(1)*Qubit('00')
>>> c
H(0)*H(1)*|00>
>>> q = qapply(c)
>>> measure_partial(q, (0,))
[(sqrt(2)*|00>/2 + sqrt(2)*|10>/2, 1/2), (sqrt(2)*|01>/2 + sqrt(2)*|11>/2, 1/2)]
"""
m = qubit_to_matrix(qubit, format)
if isinstance(bits, (SYMPY_INTS, Integer)):
bits = (int(bits),)
if format == 'sympy':
if normalize:
m = m.normalized()
possible_outcomes = _get_possible_outcomes(m, bits)
# Form output from function.
output = []
for outcome in possible_outcomes:
# Calculate probability of finding the specified bits with
# given values.
prob_of_outcome = 0
prob_of_outcome += (outcome.H*outcome)[0]
# If the output has a chance, append it to output with found
# probability.
if prob_of_outcome != 0:
if normalize:
next_matrix = matrix_to_qubit(outcome.normalized())
else:
next_matrix = matrix_to_qubit(outcome)
output.append((
next_matrix,
prob_of_outcome
))
return output
else:
raise NotImplementedError(
"This function cannot handle non-SymPy matrix formats yet"
)
def measure_partial_oneshot(qubit, bits, format='sympy'):
"""Perform a partial oneshot measurement on the specified qubits.
A oneshot measurement is equivalent to performing a measurement on a
quantum system. This type of measurement does not return the probabilities
like an ensemble measurement does, but rather returns *one* of the
possible resulting states. The exact state that is returned is determined
by picking a state randomly according to the ensemble probabilities.
Parameters
----------
qubits : Qubit
The qubit to measure. This can be any Qubit or a linear combination
of them.
bits : tuple
The qubits to measure.
format : str
The format of the intermediate matrices to use. Possible values are
('sympy','numpy','scipy.sparse'). Currently only 'sympy' is
implemented.
Returns
-------
result : Qubit
The qubit that the system collapsed to upon measurement.
"""
import random
m = qubit_to_matrix(qubit, format)
if format == 'sympy':
m = m.normalized()
possible_outcomes = _get_possible_outcomes(m, bits)
# Form output from function
random_number = random.random()
total_prob = 0
for outcome in possible_outcomes:
# Calculate probability of finding the specified bits
# with given values
total_prob += (outcome.H*outcome)[0]
if total_prob >= random_number:
return matrix_to_qubit(outcome.normalized())
else:
raise NotImplementedError(
"This function cannot handle non-SymPy matrix formats yet"
)
def _get_possible_outcomes(m, bits):
"""Get the possible states that can be produced in a measurement.
Parameters
----------
m : Matrix
The matrix representing the state of the system.
bits : tuple, list
Which bits will be measured.
Returns
-------
result : list
The list of possible states which can occur given this measurement.
These are un-normalized so we can derive the probability of finding
this state by taking the inner product with itself
"""
# This is filled with loads of dirty binary tricks...You have been warned
size = max(m.shape) # Max of shape to account for bra or ket
nqubits = int(math.log2(size) + .1) # Number of qubits possible
# Make the output states and put in output_matrices, nothing in them now.
# Each state will represent a possible outcome of the measurement
# Thus, output_matrices[0] is the matrix which we get when all measured
# bits return 0. and output_matrices[1] is the matrix for only the 0th
# bit being true
output_matrices = []
for i in range(1 << len(bits)):
output_matrices.append(zeros(2**nqubits, 1))
# Bitmasks will help sort how to determine possible outcomes.
# When the bit mask is and-ed with a matrix-index,
# it will determine which state that index belongs to
bit_masks = []
for bit in bits:
bit_masks.append(1 << bit)
# Make possible outcome states
for i in range(2**nqubits):
trueness = 0 # This tells us to which output_matrix this value belongs
# Find trueness
for j in range(len(bit_masks)):
if i & bit_masks[j]:
trueness += j + 1
# Put the value in the correct output matrix
output_matrices[trueness][i] = m[i]
return output_matrices
def measure_all_oneshot(qubit, format='sympy'):
"""Perform a oneshot ensemble measurement on all qubits.
A oneshot measurement is equivalent to performing a measurement on a
quantum system. This type of measurement does not return the probabilities
like an ensemble measurement does, but rather returns *one* of the
possible resulting states. The exact state that is returned is determined
by picking a state randomly according to the ensemble probabilities.
Parameters
----------
qubits : Qubit
The qubit to measure. This can be any Qubit or a linear combination
of them.
format : str
The format of the intermediate matrices to use. Possible values are
('sympy','numpy','scipy.sparse'). Currently only 'sympy' is
implemented.
Returns
-------
result : Qubit
The qubit that the system collapsed to upon measurement.
"""
import random
m = qubit_to_matrix(qubit)
if format == 'sympy':
m = m.normalized()
random_number = random.random()
total = 0
result = 0
for i in m:
total += i*i.conjugate()
if total > random_number:
break
result += 1
return Qubit(IntQubit(result, int(math.log2(max(m.shape)) + .1)))
else:
raise NotImplementedError(
"This function cannot handle non-SymPy matrix formats yet"
)
PK ]ZZZ[E��I I " sympy/physics/quantum/represent.py"""Logic for representing operators in state in various bases.
TODO:
* Get represent working with continuous hilbert spaces.
* Document default basis functionality.
"""
from sympy.core.add import Add
from sympy.core.expr import Expr
from sympy.core.mul import Mul
from sympy.core.numbers import I
from sympy.core.power import Pow
from sympy.integrals.integrals import integrate
from sympy.physics.quantum.dagger import Dagger
from sympy.physics.quantum.commutator import Commutator
from sympy.physics.quantum.anticommutator import AntiCommutator
from sympy.physics.quantum.innerproduct import InnerProduct
from sympy.physics.quantum.qexpr import QExpr
from sympy.physics.quantum.tensorproduct import TensorProduct
from sympy.physics.quantum.matrixutils import flatten_scalar
from sympy.physics.quantum.state import KetBase, BraBase, StateBase
from sympy.physics.quantum.operator import Operator, OuterProduct
from sympy.physics.quantum.qapply import qapply
from sympy.physics.quantum.operatorset import operators_to_state, state_to_operators
__all__ = [
'represent',
'rep_innerproduct',
'rep_expectation',
'integrate_result',
'get_basis',
'enumerate_states'
]
#-----------------------------------------------------------------------------
# Represent
#-----------------------------------------------------------------------------
def _sympy_to_scalar(e):
"""Convert from a SymPy scalar to a Python scalar."""
if isinstance(e, Expr):
if e.is_Integer:
return int(e)
elif e.is_Float:
return float(e)
elif e.is_Rational:
return float(e)
elif e.is_Number or e.is_NumberSymbol or e == I:
return complex(e)
raise TypeError('Expected number, got: %r' % e)
def represent(expr, **options):
"""Represent the quantum expression in the given basis.
In quantum mechanics abstract states and operators can be represented in
various basis sets. Under this operation the follow transforms happen:
* Ket -> column vector or function
* Bra -> row vector of function
* Operator -> matrix or differential operator
This function is the top-level interface for this action.
This function walks the SymPy expression tree looking for ``QExpr``
instances that have a ``_represent`` method. This method is then called
and the object is replaced by the representation returned by this method.
By default, the ``_represent`` method will dispatch to other methods
that handle the representation logic for a particular basis set. The
naming convention for these methods is the following::
def _represent_FooBasis(self, e, basis, **options)
This function will have the logic for representing instances of its class
in the basis set having a class named ``FooBasis``.
Parameters
==========
expr : Expr
The expression to represent.
basis : Operator, basis set
An object that contains the information about the basis set. If an
operator is used, the basis is assumed to be the orthonormal
eigenvectors of that operator. In general though, the basis argument
can be any object that contains the basis set information.
options : dict
Key/value pairs of options that are passed to the underlying method
that finds the representation. These options can be used to
control how the representation is done. For example, this is where
the size of the basis set would be set.
Returns
=======
e : Expr
The SymPy expression of the represented quantum expression.
Examples
========
Here we subclass ``Operator`` and ``Ket`` to create the z-spin operator
and its spin 1/2 up eigenstate. By defining the ``_represent_SzOp``
method, the ket can be represented in the z-spin basis.
>>> from sympy.physics.quantum import Operator, represent, Ket
>>> from sympy import Matrix
>>> class SzUpKet(Ket):
... def _represent_SzOp(self, basis, **options):
... return Matrix([1,0])
...
>>> class SzOp(Operator):
... pass
...
>>> sz = SzOp('Sz')
>>> up = SzUpKet('up')
>>> represent(up, basis=sz)
Matrix([
[1],
[0]])
Here we see an example of representations in a continuous
basis. We see that the result of representing various combinations
of cartesian position operators and kets give us continuous
expressions involving DiracDelta functions.
>>> from sympy.physics.quantum.cartesian import XOp, XKet, XBra
>>> X = XOp()
>>> x = XKet()
>>> y = XBra('y')
>>> represent(X*x)
x*DiracDelta(x - x_2)
>>> represent(X*x*y)
x*DiracDelta(x - x_3)*DiracDelta(x_1 - y)
"""
format = options.get('format', 'sympy')
if format == 'numpy':
import numpy as np
if isinstance(expr, QExpr) and not isinstance(expr, OuterProduct):
options['replace_none'] = False
temp_basis = get_basis(expr, **options)
if temp_basis is not None:
options['basis'] = temp_basis
try:
return expr._represent(**options)
except NotImplementedError as strerr:
#If no _represent_FOO method exists, map to the
#appropriate basis state and try
#the other methods of representation
options['replace_none'] = True
if isinstance(expr, (KetBase, BraBase)):
try:
return rep_innerproduct(expr, **options)
except NotImplementedError:
raise NotImplementedError(strerr)
elif isinstance(expr, Operator):
try:
return rep_expectation(expr, **options)
except NotImplementedError:
raise NotImplementedError(strerr)
else:
raise NotImplementedError(strerr)
elif isinstance(expr, Add):
result = represent(expr.args[0], **options)
for args in expr.args[1:]:
# scipy.sparse doesn't support += so we use plain = here.
result = result + represent(args, **options)
return result
elif isinstance(expr, Pow):
base, exp = expr.as_base_exp()
if format in ('numpy', 'scipy.sparse'):
exp = _sympy_to_scalar(exp)
base = represent(base, **options)
# scipy.sparse doesn't support negative exponents
# and warns when inverting a matrix in csr format.
if format == 'scipy.sparse' and exp < 0:
from scipy.sparse.linalg import inv
exp = - exp
base = inv(base.tocsc()).tocsr()
if format == 'numpy':
return np.linalg.matrix_power(base, exp)
return base ** exp
elif isinstance(expr, TensorProduct):
new_args = [represent(arg, **options) for arg in expr.args]
return TensorProduct(*new_args)
elif isinstance(expr, Dagger):
return Dagger(represent(expr.args[0], **options))
elif isinstance(expr, Commutator):
A = expr.args[0]
B = expr.args[1]
return represent(Mul(A, B) - Mul(B, A), **options)
elif isinstance(expr, AntiCommutator):
A = expr.args[0]
B = expr.args[1]
return represent(Mul(A, B) + Mul(B, A), **options)
elif isinstance(expr, InnerProduct):
return represent(Mul(expr.bra, expr.ket), **options)
elif not isinstance(expr, (Mul, OuterProduct)):
# For numpy and scipy.sparse, we can only handle numerical prefactors.
if format in ('numpy', 'scipy.sparse'):
return _sympy_to_scalar(expr)
return expr
if not isinstance(expr, (Mul, OuterProduct)):
raise TypeError('Mul expected, got: %r' % expr)
if "index" in options:
options["index"] += 1
else:
options["index"] = 1
if "unities" not in options:
options["unities"] = []
result = represent(expr.args[-1], **options)
last_arg = expr.args[-1]
for arg in reversed(expr.args[:-1]):
if isinstance(last_arg, Operator):
options["index"] += 1
options["unities"].append(options["index"])
elif isinstance(last_arg, BraBase) and isinstance(arg, KetBase):
options["index"] += 1
elif isinstance(last_arg, KetBase) and isinstance(arg, Operator):
options["unities"].append(options["index"])
elif isinstance(last_arg, KetBase) and isinstance(arg, BraBase):
options["unities"].append(options["index"])
next_arg = represent(arg, **options)
if format == 'numpy' and isinstance(next_arg, np.ndarray):
# Must use np.matmult to "matrix multiply" two np.ndarray
result = np.matmul(next_arg, result)
else:
result = next_arg*result
last_arg = arg
# All three matrix formats create 1 by 1 matrices when inner products of
# vectors are taken. In these cases, we simply return a scalar.
result = flatten_scalar(result)
result = integrate_result(expr, result, **options)
return result
def rep_innerproduct(expr, **options):
"""
Returns an innerproduct like representation (e.g. ``<x'|x>``) for the
given state.
Attempts to calculate inner product with a bra from the specified
basis. Should only be passed an instance of KetBase or BraBase
Parameters
==========
expr : KetBase or BraBase
The expression to be represented
Examples
========
>>> from sympy.physics.quantum.represent import rep_innerproduct
>>> from sympy.physics.quantum.cartesian import XOp, XKet, PxOp, PxKet
>>> rep_innerproduct(XKet())
DiracDelta(x - x_1)
>>> rep_innerproduct(XKet(), basis=PxOp())
sqrt(2)*exp(-I*px_1*x/hbar)/(2*sqrt(hbar)*sqrt(pi))
>>> rep_innerproduct(PxKet(), basis=XOp())
sqrt(2)*exp(I*px*x_1/hbar)/(2*sqrt(hbar)*sqrt(pi))
"""
if not isinstance(expr, (KetBase, BraBase)):
raise TypeError("expr passed is not a Bra or Ket")
basis = get_basis(expr, **options)
if not isinstance(basis, StateBase):
raise NotImplementedError("Can't form this representation!")
if "index" not in options:
options["index"] = 1
basis_kets = enumerate_states(basis, options["index"], 2)
if isinstance(expr, BraBase):
bra = expr
ket = (basis_kets[1] if basis_kets[0].dual == expr else basis_kets[0])
else:
bra = (basis_kets[1].dual if basis_kets[0]
== expr else basis_kets[0].dual)
ket = expr
prod = InnerProduct(bra, ket)
result = prod.doit()
format = options.get('format', 'sympy')
return expr._format_represent(result, format)
def rep_expectation(expr, **options):
"""
Returns an ``<x'|A|x>`` type representation for the given operator.
Parameters
==========
expr : Operator
Operator to be represented in the specified basis
Examples
========
>>> from sympy.physics.quantum.cartesian import XOp, PxOp, PxKet
>>> from sympy.physics.quantum.represent import rep_expectation
>>> rep_expectation(XOp())
x_1*DiracDelta(x_1 - x_2)
>>> rep_expectation(XOp(), basis=PxOp())
<px_2|*X*|px_1>
>>> rep_expectation(XOp(), basis=PxKet())
<px_2|*X*|px_1>
"""
if "index" not in options:
options["index"] = 1
if not isinstance(expr, Operator):
raise TypeError("The passed expression is not an operator")
basis_state = get_basis(expr, **options)
if basis_state is None or not isinstance(basis_state, StateBase):
raise NotImplementedError("Could not get basis kets for this operator")
basis_kets = enumerate_states(basis_state, options["index"], 2)
bra = basis_kets[1].dual
ket = basis_kets[0]
return qapply(bra*expr*ket)
def integrate_result(orig_expr, result, **options):
"""
Returns the result of integrating over any unities ``(|x><x|)`` in
the given expression. Intended for integrating over the result of
representations in continuous bases.
This function integrates over any unities that may have been
inserted into the quantum expression and returns the result.
It uses the interval of the Hilbert space of the basis state
passed to it in order to figure out the limits of integration.
The unities option must be
specified for this to work.
Note: This is mostly used internally by represent(). Examples are
given merely to show the use cases.
Parameters
==========
orig_expr : quantum expression
The original expression which was to be represented
result: Expr
The resulting representation that we wish to integrate over
Examples
========
>>> from sympy import symbols, DiracDelta
>>> from sympy.physics.quantum.represent import integrate_result
>>> from sympy.physics.quantum.cartesian import XOp, XKet
>>> x_ket = XKet()
>>> X_op = XOp()
>>> x, x_1, x_2 = symbols('x, x_1, x_2')
>>> integrate_result(X_op*x_ket, x*DiracDelta(x-x_1)*DiracDelta(x_1-x_2))
x*DiracDelta(x - x_1)*DiracDelta(x_1 - x_2)
>>> integrate_result(X_op*x_ket, x*DiracDelta(x-x_1)*DiracDelta(x_1-x_2),
... unities=[1])
x*DiracDelta(x - x_2)
"""
if not isinstance(result, Expr):
return result
options['replace_none'] = True
if "basis" not in options:
arg = orig_expr.args[-1]
options["basis"] = get_basis(arg, **options)
elif not isinstance(options["basis"], StateBase):
options["basis"] = get_basis(orig_expr, **options)
basis = options.pop("basis", None)
if basis is None:
return result
unities = options.pop("unities", [])
if len(unities) == 0:
return result
kets = enumerate_states(basis, unities)
coords = [k.label[0] for k in kets]
for coord in coords:
if coord in result.free_symbols:
#TODO: Add support for sets of operators
basis_op = state_to_operators(basis)
start = basis_op.hilbert_space.interval.start
end = basis_op.hilbert_space.interval.end
result = integrate(result, (coord, start, end))
return result
def get_basis(expr, *, basis=None, replace_none=True, **options):
"""
Returns a basis state instance corresponding to the basis specified in
options=s. If no basis is specified, the function tries to form a default
basis state of the given expression.
There are three behaviors:
1. The basis specified in options is already an instance of StateBase. If
this is the case, it is simply returned. If the class is specified but
not an instance, a default instance is returned.
2. The basis specified is an operator or set of operators. If this
is the case, the operator_to_state mapping method is used.
3. No basis is specified. If expr is a state, then a default instance of
its class is returned. If expr is an operator, then it is mapped to the
corresponding state. If it is neither, then we cannot obtain the basis
state.
If the basis cannot be mapped, then it is not changed.
This will be called from within represent, and represent will
only pass QExpr's.
TODO (?): Support for Muls and other types of expressions?
Parameters
==========
expr : Operator or StateBase
Expression whose basis is sought
Examples
========
>>> from sympy.physics.quantum.represent import get_basis
>>> from sympy.physics.quantum.cartesian import XOp, XKet, PxOp, PxKet
>>> x = XKet()
>>> X = XOp()
>>> get_basis(x)
|x>
>>> get_basis(X)
|x>
>>> get_basis(x, basis=PxOp())
|px>
>>> get_basis(x, basis=PxKet)
|px>
"""
if basis is None and not replace_none:
return None
if basis is None:
if isinstance(expr, KetBase):
return _make_default(expr.__class__)
elif isinstance(expr, BraBase):
return _make_default(expr.dual_class())
elif isinstance(expr, Operator):
state_inst = operators_to_state(expr)
return (state_inst if state_inst is not None else None)
else:
return None
elif (isinstance(basis, Operator) or
(not isinstance(basis, StateBase) and issubclass(basis, Operator))):
state = operators_to_state(basis)
if state is None:
return None
elif isinstance(state, StateBase):
return state
else:
return _make_default(state)
elif isinstance(basis, StateBase):
return basis
elif issubclass(basis, StateBase):
return _make_default(basis)
else:
return None
def _make_default(expr):
# XXX: Catching TypeError like this is a bad way of distinguishing
# instances from classes. The logic using this function should be
# rewritten somehow.
try:
expr = expr()
except TypeError:
return expr
return expr
def enumerate_states(*args, **options):
"""
Returns instances of the given state with dummy indices appended
Operates in two different modes:
1. Two arguments are passed to it. The first is the base state which is to
be indexed, and the second argument is a list of indices to append.
2. Three arguments are passed. The first is again the base state to be
indexed. The second is the start index for counting. The final argument
is the number of kets you wish to receive.
Tries to call state._enumerate_state. If this fails, returns an empty list
Parameters
==========
args : list
See list of operation modes above for explanation
Examples
========
>>> from sympy.physics.quantum.cartesian import XBra, XKet
>>> from sympy.physics.quantum.represent import enumerate_states
>>> test = XKet('foo')
>>> enumerate_states(test, 1, 3)
[|foo_1>, |foo_2>, |foo_3>]
>>> test2 = XBra('bar')
>>> enumerate_states(test2, [4, 5, 10])
[<bar_4|, <bar_5|, <bar_10|]
"""
state = args[0]
if len(args) not in (2, 3):
raise NotImplementedError("Wrong number of arguments!")
if not isinstance(state, StateBase):
raise TypeError("First argument is not a state!")
if len(args) == 3:
num_states = args[2]
options['start_index'] = args[1]
else:
num_states = len(args[1])
options['index_list'] = args[1]
try:
ret = state._enumerate_state(num_states, **options)
except NotImplementedError:
ret = []
return ret
PK ]ZZZ���R�Q �Q sympy/physics/quantum/sho1d.py"""Simple Harmonic Oscillator 1-Dimension"""
from sympy.core.numbers import (I, Integer)
from sympy.core.singleton import S
from sympy.core.symbol import Symbol
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.physics.quantum.constants import hbar
from sympy.physics.quantum.operator import Operator
from sympy.physics.quantum.state import Bra, Ket, State
from sympy.physics.quantum.qexpr import QExpr
from sympy.physics.quantum.cartesian import X, Px
from sympy.functions.special.tensor_functions import KroneckerDelta
from sympy.physics.quantum.hilbert import ComplexSpace
from sympy.physics.quantum.matrixutils import matrix_zeros
#------------------------------------------------------------------------------
class SHOOp(Operator):
"""A base class for the SHO Operators.
We are limiting the number of arguments to be 1.
"""
@classmethod
def _eval_args(cls, args):
args = QExpr._eval_args(args)
if len(args) == 1:
return args
else:
raise ValueError("Too many arguments")
@classmethod
def _eval_hilbert_space(cls, label):
return ComplexSpace(S.Infinity)
class RaisingOp(SHOOp):
"""The Raising Operator or a^dagger.
When a^dagger acts on a state it raises the state up by one. Taking
the adjoint of a^dagger returns 'a', the Lowering Operator. a^dagger
can be rewritten in terms of position and momentum. We can represent
a^dagger as a matrix, which will be its default basis.
Parameters
==========
args : tuple
The list of numbers or parameters that uniquely specify the
operator.
Examples
========
Create a Raising Operator and rewrite it in terms of position and
momentum, and show that taking its adjoint returns 'a':
>>> from sympy.physics.quantum.sho1d import RaisingOp
>>> from sympy.physics.quantum import Dagger
>>> ad = RaisingOp('a')
>>> ad.rewrite('xp').doit()
sqrt(2)*(m*omega*X - I*Px)/(2*sqrt(hbar)*sqrt(m*omega))
>>> Dagger(ad)
a
Taking the commutator of a^dagger with other Operators:
>>> from sympy.physics.quantum import Commutator
>>> from sympy.physics.quantum.sho1d import RaisingOp, LoweringOp
>>> from sympy.physics.quantum.sho1d import NumberOp
>>> ad = RaisingOp('a')
>>> a = LoweringOp('a')
>>> N = NumberOp('N')
>>> Commutator(ad, a).doit()
-1
>>> Commutator(ad, N).doit()
-RaisingOp(a)
Apply a^dagger to a state:
>>> from sympy.physics.quantum import qapply
>>> from sympy.physics.quantum.sho1d import RaisingOp, SHOKet
>>> ad = RaisingOp('a')
>>> k = SHOKet('k')
>>> qapply(ad*k)
sqrt(k + 1)*|k + 1>
Matrix Representation
>>> from sympy.physics.quantum.sho1d import RaisingOp
>>> from sympy.physics.quantum.represent import represent
>>> ad = RaisingOp('a')
>>> represent(ad, basis=N, ndim=4, format='sympy')
Matrix([
[0, 0, 0, 0],
[1, 0, 0, 0],
[0, sqrt(2), 0, 0],
[0, 0, sqrt(3), 0]])
"""
def _eval_rewrite_as_xp(self, *args, **kwargs):
return (S.One/sqrt(Integer(2)*hbar*m*omega))*(
S.NegativeOne*I*Px + m*omega*X)
def _eval_adjoint(self):
return LoweringOp(*self.args)
def _eval_commutator_LoweringOp(self, other):
return S.NegativeOne
def _eval_commutator_NumberOp(self, other):
return S.NegativeOne*self
def _apply_operator_SHOKet(self, ket, **options):
temp = ket.n + S.One
return sqrt(temp)*SHOKet(temp)
def _represent_default_basis(self, **options):
return self._represent_NumberOp(None, **options)
def _represent_XOp(self, basis, **options):
# This logic is good but the underlying position
# representation logic is broken.
# temp = self.rewrite('xp').doit()
# result = represent(temp, basis=X)
# return result
raise NotImplementedError('Position representation is not implemented')
def _represent_NumberOp(self, basis, **options):
ndim_info = options.get('ndim', 4)
format = options.get('format','sympy')
matrix = matrix_zeros(ndim_info, ndim_info, **options)
for i in range(ndim_info - 1):
value = sqrt(i + 1)
if format == 'scipy.sparse':
value = float(value)
matrix[i + 1, i] = value
if format == 'scipy.sparse':
matrix = matrix.tocsr()
return matrix
#--------------------------------------------------------------------------
# Printing Methods
#--------------------------------------------------------------------------
def _print_contents(self, printer, *args):
arg0 = printer._print(self.args[0], *args)
return '%s(%s)' % (self.__class__.__name__, arg0)
def _print_contents_pretty(self, printer, *args):
from sympy.printing.pretty.stringpict import prettyForm
pform = printer._print(self.args[0], *args)
pform = pform**prettyForm('\N{DAGGER}')
return pform
def _print_contents_latex(self, printer, *args):
arg = printer._print(self.args[0])
return '%s^{\\dagger}' % arg
class LoweringOp(SHOOp):
"""The Lowering Operator or 'a'.
When 'a' acts on a state it lowers the state up by one. Taking
the adjoint of 'a' returns a^dagger, the Raising Operator. 'a'
can be rewritten in terms of position and momentum. We can
represent 'a' as a matrix, which will be its default basis.
Parameters
==========
args : tuple
The list of numbers or parameters that uniquely specify the
operator.
Examples
========
Create a Lowering Operator and rewrite it in terms of position and
momentum, and show that taking its adjoint returns a^dagger:
>>> from sympy.physics.quantum.sho1d import LoweringOp
>>> from sympy.physics.quantum import Dagger
>>> a = LoweringOp('a')
>>> a.rewrite('xp').doit()
sqrt(2)*(m*omega*X + I*Px)/(2*sqrt(hbar)*sqrt(m*omega))
>>> Dagger(a)
RaisingOp(a)
Taking the commutator of 'a' with other Operators:
>>> from sympy.physics.quantum import Commutator
>>> from sympy.physics.quantum.sho1d import LoweringOp, RaisingOp
>>> from sympy.physics.quantum.sho1d import NumberOp
>>> a = LoweringOp('a')
>>> ad = RaisingOp('a')
>>> N = NumberOp('N')
>>> Commutator(a, ad).doit()
1
>>> Commutator(a, N).doit()
a
Apply 'a' to a state:
>>> from sympy.physics.quantum import qapply
>>> from sympy.physics.quantum.sho1d import LoweringOp, SHOKet
>>> a = LoweringOp('a')
>>> k = SHOKet('k')
>>> qapply(a*k)
sqrt(k)*|k - 1>
Taking 'a' of the lowest state will return 0:
>>> from sympy.physics.quantum import qapply
>>> from sympy.physics.quantum.sho1d import LoweringOp, SHOKet
>>> a = LoweringOp('a')
>>> k = SHOKet(0)
>>> qapply(a*k)
0
Matrix Representation
>>> from sympy.physics.quantum.sho1d import LoweringOp
>>> from sympy.physics.quantum.represent import represent
>>> a = LoweringOp('a')
>>> represent(a, basis=N, ndim=4, format='sympy')
Matrix([
[0, 1, 0, 0],
[0, 0, sqrt(2), 0],
[0, 0, 0, sqrt(3)],
[0, 0, 0, 0]])
"""
def _eval_rewrite_as_xp(self, *args, **kwargs):
return (S.One/sqrt(Integer(2)*hbar*m*omega))*(
I*Px + m*omega*X)
def _eval_adjoint(self):
return RaisingOp(*self.args)
def _eval_commutator_RaisingOp(self, other):
return S.One
def _eval_commutator_NumberOp(self, other):
return self
def _apply_operator_SHOKet(self, ket, **options):
temp = ket.n - Integer(1)
if ket.n is S.Zero:
return S.Zero
else:
return sqrt(ket.n)*SHOKet(temp)
def _represent_default_basis(self, **options):
return self._represent_NumberOp(None, **options)
def _represent_XOp(self, basis, **options):
# This logic is good but the underlying position
# representation logic is broken.
# temp = self.rewrite('xp').doit()
# result = represent(temp, basis=X)
# return result
raise NotImplementedError('Position representation is not implemented')
def _represent_NumberOp(self, basis, **options):
ndim_info = options.get('ndim', 4)
format = options.get('format', 'sympy')
matrix = matrix_zeros(ndim_info, ndim_info, **options)
for i in range(ndim_info - 1):
value = sqrt(i + 1)
if format == 'scipy.sparse':
value = float(value)
matrix[i,i + 1] = value
if format == 'scipy.sparse':
matrix = matrix.tocsr()
return matrix
class NumberOp(SHOOp):
"""The Number Operator is simply a^dagger*a
It is often useful to write a^dagger*a as simply the Number Operator
because the Number Operator commutes with the Hamiltonian. And can be
expressed using the Number Operator. Also the Number Operator can be
applied to states. We can represent the Number Operator as a matrix,
which will be its default basis.
Parameters
==========
args : tuple
The list of numbers or parameters that uniquely specify the
operator.
Examples
========
Create a Number Operator and rewrite it in terms of the ladder
operators, position and momentum operators, and Hamiltonian:
>>> from sympy.physics.quantum.sho1d import NumberOp
>>> N = NumberOp('N')
>>> N.rewrite('a').doit()
RaisingOp(a)*a
>>> N.rewrite('xp').doit()
-1/2 + (m**2*omega**2*X**2 + Px**2)/(2*hbar*m*omega)
>>> N.rewrite('H').doit()
-1/2 + H/(hbar*omega)
Take the Commutator of the Number Operator with other Operators:
>>> from sympy.physics.quantum import Commutator
>>> from sympy.physics.quantum.sho1d import NumberOp, Hamiltonian
>>> from sympy.physics.quantum.sho1d import RaisingOp, LoweringOp
>>> N = NumberOp('N')
>>> H = Hamiltonian('H')
>>> ad = RaisingOp('a')
>>> a = LoweringOp('a')
>>> Commutator(N,H).doit()
0
>>> Commutator(N,ad).doit()
RaisingOp(a)
>>> Commutator(N,a).doit()
-a
Apply the Number Operator to a state:
>>> from sympy.physics.quantum import qapply
>>> from sympy.physics.quantum.sho1d import NumberOp, SHOKet
>>> N = NumberOp('N')
>>> k = SHOKet('k')
>>> qapply(N*k)
k*|k>
Matrix Representation
>>> from sympy.physics.quantum.sho1d import NumberOp
>>> from sympy.physics.quantum.represent import represent
>>> N = NumberOp('N')
>>> represent(N, basis=N, ndim=4, format='sympy')
Matrix([
[0, 0, 0, 0],
[0, 1, 0, 0],
[0, 0, 2, 0],
[0, 0, 0, 3]])
"""
def _eval_rewrite_as_a(self, *args, **kwargs):
return ad*a
def _eval_rewrite_as_xp(self, *args, **kwargs):
return (S.One/(Integer(2)*m*hbar*omega))*(Px**2 + (
m*omega*X)**2) - S.Half
def _eval_rewrite_as_H(self, *args, **kwargs):
return H/(hbar*omega) - S.Half
def _apply_operator_SHOKet(self, ket, **options):
return ket.n*ket
def _eval_commutator_Hamiltonian(self, other):
return S.Zero
def _eval_commutator_RaisingOp(self, other):
return other
def _eval_commutator_LoweringOp(self, other):
return S.NegativeOne*other
def _represent_default_basis(self, **options):
return self._represent_NumberOp(None, **options)
def _represent_XOp(self, basis, **options):
# This logic is good but the underlying position
# representation logic is broken.
# temp = self.rewrite('xp').doit()
# result = represent(temp, basis=X)
# return result
raise NotImplementedError('Position representation is not implemented')
def _represent_NumberOp(self, basis, **options):
ndim_info = options.get('ndim', 4)
format = options.get('format', 'sympy')
matrix = matrix_zeros(ndim_info, ndim_info, **options)
for i in range(ndim_info):
value = i
if format == 'scipy.sparse':
value = float(value)
matrix[i,i] = value
if format == 'scipy.sparse':
matrix = matrix.tocsr()
return matrix
class Hamiltonian(SHOOp):
"""The Hamiltonian Operator.
The Hamiltonian is used to solve the time-independent Schrodinger
equation. The Hamiltonian can be expressed using the ladder operators,
as well as by position and momentum. We can represent the Hamiltonian
Operator as a matrix, which will be its default basis.
Parameters
==========
args : tuple
The list of numbers or parameters that uniquely specify the
operator.
Examples
========
Create a Hamiltonian Operator and rewrite it in terms of the ladder
operators, position and momentum, and the Number Operator:
>>> from sympy.physics.quantum.sho1d import Hamiltonian
>>> H = Hamiltonian('H')
>>> H.rewrite('a').doit()
hbar*omega*(1/2 + RaisingOp(a)*a)
>>> H.rewrite('xp').doit()
(m**2*omega**2*X**2 + Px**2)/(2*m)
>>> H.rewrite('N').doit()
hbar*omega*(1/2 + N)
Take the Commutator of the Hamiltonian and the Number Operator:
>>> from sympy.physics.quantum import Commutator
>>> from sympy.physics.quantum.sho1d import Hamiltonian, NumberOp
>>> H = Hamiltonian('H')
>>> N = NumberOp('N')
>>> Commutator(H,N).doit()
0
Apply the Hamiltonian Operator to a state:
>>> from sympy.physics.quantum import qapply
>>> from sympy.physics.quantum.sho1d import Hamiltonian, SHOKet
>>> H = Hamiltonian('H')
>>> k = SHOKet('k')
>>> qapply(H*k)
hbar*k*omega*|k> + hbar*omega*|k>/2
Matrix Representation
>>> from sympy.physics.quantum.sho1d import Hamiltonian
>>> from sympy.physics.quantum.represent import represent
>>> H = Hamiltonian('H')
>>> represent(H, basis=N, ndim=4, format='sympy')
Matrix([
[hbar*omega/2, 0, 0, 0],
[ 0, 3*hbar*omega/2, 0, 0],
[ 0, 0, 5*hbar*omega/2, 0],
[ 0, 0, 0, 7*hbar*omega/2]])
"""
def _eval_rewrite_as_a(self, *args, **kwargs):
return hbar*omega*(ad*a + S.Half)
def _eval_rewrite_as_xp(self, *args, **kwargs):
return (S.One/(Integer(2)*m))*(Px**2 + (m*omega*X)**2)
def _eval_rewrite_as_N(self, *args, **kwargs):
return hbar*omega*(N + S.Half)
def _apply_operator_SHOKet(self, ket, **options):
return (hbar*omega*(ket.n + S.Half))*ket
def _eval_commutator_NumberOp(self, other):
return S.Zero
def _represent_default_basis(self, **options):
return self._represent_NumberOp(None, **options)
def _represent_XOp(self, basis, **options):
# This logic is good but the underlying position
# representation logic is broken.
# temp = self.rewrite('xp').doit()
# result = represent(temp, basis=X)
# return result
raise NotImplementedError('Position representation is not implemented')
def _represent_NumberOp(self, basis, **options):
ndim_info = options.get('ndim', 4)
format = options.get('format', 'sympy')
matrix = matrix_zeros(ndim_info, ndim_info, **options)
for i in range(ndim_info):
value = i + S.Half
if format == 'scipy.sparse':
value = float(value)
matrix[i,i] = value
if format == 'scipy.sparse':
matrix = matrix.tocsr()
return hbar*omega*matrix
#------------------------------------------------------------------------------
class SHOState(State):
"""State class for SHO states"""
@classmethod
def _eval_hilbert_space(cls, label):
return ComplexSpace(S.Infinity)
@property
def n(self):
return self.args[0]
class SHOKet(SHOState, Ket):
"""1D eigenket.
Inherits from SHOState and Ket.
Parameters
==========
args : tuple
The list of numbers or parameters that uniquely specify the ket
This is usually its quantum numbers or its symbol.
Examples
========
Ket's know about their associated bra:
>>> from sympy.physics.quantum.sho1d import SHOKet
>>> k = SHOKet('k')
>>> k.dual
<k|
>>> k.dual_class()
<class 'sympy.physics.quantum.sho1d.SHOBra'>
Take the Inner Product with a bra:
>>> from sympy.physics.quantum import InnerProduct
>>> from sympy.physics.quantum.sho1d import SHOKet, SHOBra
>>> k = SHOKet('k')
>>> b = SHOBra('b')
>>> InnerProduct(b,k).doit()
KroneckerDelta(b, k)
Vector representation of a numerical state ket:
>>> from sympy.physics.quantum.sho1d import SHOKet, NumberOp
>>> from sympy.physics.quantum.represent import represent
>>> k = SHOKet(3)
>>> N = NumberOp('N')
>>> represent(k, basis=N, ndim=4)
Matrix([
[0],
[0],
[0],
[1]])
"""
@classmethod
def dual_class(self):
return SHOBra
def _eval_innerproduct_SHOBra(self, bra, **hints):
result = KroneckerDelta(self.n, bra.n)
return result
def _represent_default_basis(self, **options):
return self._represent_NumberOp(None, **options)
def _represent_NumberOp(self, basis, **options):
ndim_info = options.get('ndim', 4)
format = options.get('format', 'sympy')
options['spmatrix'] = 'lil'
vector = matrix_zeros(ndim_info, 1, **options)
if isinstance(self.n, Integer):
if self.n >= ndim_info:
return ValueError("N-Dimension too small")
if format == 'scipy.sparse':
vector[int(self.n), 0] = 1.0
vector = vector.tocsr()
elif format == 'numpy':
vector[int(self.n), 0] = 1.0
else:
vector[self.n, 0] = S.One
return vector
else:
return ValueError("Not Numerical State")
class SHOBra(SHOState, Bra):
"""A time-independent Bra in SHO.
Inherits from SHOState and Bra.
Parameters
==========
args : tuple
The list of numbers or parameters that uniquely specify the ket
This is usually its quantum numbers or its symbol.
Examples
========
Bra's know about their associated ket:
>>> from sympy.physics.quantum.sho1d import SHOBra
>>> b = SHOBra('b')
>>> b.dual
|b>
>>> b.dual_class()
<class 'sympy.physics.quantum.sho1d.SHOKet'>
Vector representation of a numerical state bra:
>>> from sympy.physics.quantum.sho1d import SHOBra, NumberOp
>>> from sympy.physics.quantum.represent import represent
>>> b = SHOBra(3)
>>> N = NumberOp('N')
>>> represent(b, basis=N, ndim=4)
Matrix([[0, 0, 0, 1]])
"""
@classmethod
def dual_class(self):
return SHOKet
def _represent_default_basis(self, **options):
return self._represent_NumberOp(None, **options)
def _represent_NumberOp(self, basis, **options):
ndim_info = options.get('ndim', 4)
format = options.get('format', 'sympy')
options['spmatrix'] = 'lil'
vector = matrix_zeros(1, ndim_info, **options)
if isinstance(self.n, Integer):
if self.n >= ndim_info:
return ValueError("N-Dimension too small")
if format == 'scipy.sparse':
vector[0, int(self.n)] = 1.0
vector = vector.tocsr()
elif format == 'numpy':
vector[0, int(self.n)] = 1.0
else:
vector[0, self.n] = S.One
return vector
else:
return ValueError("Not Numerical State")
ad = RaisingOp('a')
a = LoweringOp('a')
H = Hamiltonian('H')
N = NumberOp('N')
omega = Symbol('omega')
m = Symbol('m')
PK ]ZZZaϜ � � sympy/physics/quantum/shor.py"""Shor's algorithm and helper functions.
Todo:
* Get the CMod gate working again using the new Gate API.
* Fix everything.
* Update docstrings and reformat.
"""
import math
import random
from sympy.core.mul import Mul
from sympy.core.singleton import S
from sympy.functions.elementary.exponential import log
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.core.intfunc import igcd
from sympy.ntheory import continued_fraction_periodic as continued_fraction
from sympy.utilities.iterables import variations
from sympy.physics.quantum.gate import Gate
from sympy.physics.quantum.qubit import Qubit, measure_partial_oneshot
from sympy.physics.quantum.qapply import qapply
from sympy.physics.quantum.qft import QFT
from sympy.physics.quantum.qexpr import QuantumError
class OrderFindingException(QuantumError):
pass
class CMod(Gate):
"""A controlled mod gate.
This is black box controlled Mod function for use by shor's algorithm.
TODO: implement a decompose property that returns how to do this in terms
of elementary gates
"""
@classmethod
def _eval_args(cls, args):
# t = args[0]
# a = args[1]
# N = args[2]
raise NotImplementedError('The CMod gate has not been completed.')
@property
def t(self):
"""Size of 1/2 input register. First 1/2 holds output."""
return self.label[0]
@property
def a(self):
"""Base of the controlled mod function."""
return self.label[1]
@property
def N(self):
"""N is the type of modular arithmetic we are doing."""
return self.label[2]
def _apply_operator_Qubit(self, qubits, **options):
"""
This directly calculates the controlled mod of the second half of
the register and puts it in the second
This will look pretty when we get Tensor Symbolically working
"""
n = 1
k = 0
# Determine the value stored in high memory.
for i in range(self.t):
k += n*qubits[self.t + i]
n *= 2
# The value to go in low memory will be out.
out = int(self.a**k % self.N)
# Create array for new qbit-ket which will have high memory unaffected
outarray = list(qubits.args[0][:self.t])
# Place out in low memory
for i in reversed(range(self.t)):
outarray.append((out >> i) & 1)
return Qubit(*outarray)
def shor(N):
"""This function implements Shor's factoring algorithm on the Integer N
The algorithm starts by picking a random number (a) and seeing if it is
coprime with N. If it is not, then the gcd of the two numbers is a factor
and we are done. Otherwise, it begins the period_finding subroutine which
finds the period of a in modulo N arithmetic. This period, if even, can
be used to calculate factors by taking a**(r/2)-1 and a**(r/2)+1.
These values are returned.
"""
a = random.randrange(N - 2) + 2
if igcd(N, a) != 1:
return igcd(N, a)
r = period_find(a, N)
if r % 2 == 1:
shor(N)
answer = (igcd(a**(r/2) - 1, N), igcd(a**(r/2) + 1, N))
return answer
def getr(x, y, N):
fraction = continued_fraction(x, y)
# Now convert into r
total = ratioize(fraction, N)
return total
def ratioize(list, N):
if list[0] > N:
return S.Zero
if len(list) == 1:
return list[0]
return list[0] + ratioize(list[1:], N)
def period_find(a, N):
"""Finds the period of a in modulo N arithmetic
This is quantum part of Shor's algorithm. It takes two registers,
puts first in superposition of states with Hadamards so: ``|k>|0>``
with k being all possible choices. It then does a controlled mod and
a QFT to determine the order of a.
"""
epsilon = .5
# picks out t's such that maintains accuracy within epsilon
t = int(2*math.ceil(log(N, 2)))
# make the first half of register be 0's |000...000>
start = [0 for x in range(t)]
# Put second half into superposition of states so we have |1>x|0> + |2>x|0> + ... |k>x>|0> + ... + |2**n-1>x|0>
factor = 1/sqrt(2**t)
qubits = 0
for arr in variations(range(2), t, repetition=True):
qbitArray = list(arr) + start
qubits = qubits + Qubit(*qbitArray)
circuit = (factor*qubits).expand()
# Controlled second half of register so that we have:
# |1>x|a**1 %N> + |2>x|a**2 %N> + ... + |k>x|a**k %N >+ ... + |2**n-1=k>x|a**k % n>
circuit = CMod(t, a, N)*circuit
# will measure first half of register giving one of the a**k%N's
circuit = qapply(circuit)
for i in range(t):
circuit = measure_partial_oneshot(circuit, i)
# Now apply Inverse Quantum Fourier Transform on the second half of the register
circuit = qapply(QFT(t, t*2).decompose()*circuit, floatingPoint=True)
for i in range(t):
circuit = measure_partial_oneshot(circuit, i + t)
if isinstance(circuit, Qubit):
register = circuit
elif isinstance(circuit, Mul):
register = circuit.args[-1]
else:
register = circuit.args[-1].args[-1]
n = 1
answer = 0
for i in range(len(register)/2):
answer += n*register[i + t]
n = n << 1
if answer == 0:
raise OrderFindingException(
"Order finder returned 0. Happens with chance %f" % epsilon)
#turn answer into r using continued fractions
g = getr(answer, 2**t, N)
return g
PK ]ZZZX�/ sympy/physics/quantum/spin.py"""Quantum mechanical angular momemtum."""
from sympy.concrete.summations import Sum
from sympy.core.add import Add
from sympy.core.containers import Tuple
from sympy.core.expr import Expr
from sympy.core.numbers import int_valued
from sympy.core.mul import Mul
from sympy.core.numbers import (I, Integer, Rational, pi)
from sympy.core.singleton import S
from sympy.core.symbol import (Dummy, symbols)
from sympy.core.sympify import sympify
from sympy.functions.combinatorial.factorials import (binomial, factorial)
from sympy.functions.elementary.exponential import exp
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.elementary.trigonometric import (cos, sin)
from sympy.simplify.simplify import simplify
from sympy.matrices import zeros
from sympy.printing.pretty.stringpict import prettyForm, stringPict
from sympy.printing.pretty.pretty_symbology import pretty_symbol
from sympy.physics.quantum.qexpr import QExpr
from sympy.physics.quantum.operator import (HermitianOperator, Operator,
UnitaryOperator)
from sympy.physics.quantum.state import Bra, Ket, State
from sympy.functions.special.tensor_functions import KroneckerDelta
from sympy.physics.quantum.constants import hbar
from sympy.physics.quantum.hilbert import ComplexSpace, DirectSumHilbertSpace
from sympy.physics.quantum.tensorproduct import TensorProduct
from sympy.physics.quantum.cg import CG
from sympy.physics.quantum.qapply import qapply
__all__ = [
'm_values',
'Jplus',
'Jminus',
'Jx',
'Jy',
'Jz',
'J2',
'Rotation',
'WignerD',
'JxKet',
'JxBra',
'JyKet',
'JyBra',
'JzKet',
'JzBra',
'JzOp',
'J2Op',
'JxKetCoupled',
'JxBraCoupled',
'JyKetCoupled',
'JyBraCoupled',
'JzKetCoupled',
'JzBraCoupled',
'couple',
'uncouple'
]
def m_values(j):
j = sympify(j)
size = 2*j + 1
if not size.is_Integer or not size > 0:
raise ValueError(
'Only integer or half-integer values allowed for j, got: : %r' % j
)
return size, [j - i for i in range(int(2*j + 1))]
#-----------------------------------------------------------------------------
# Spin Operators
#-----------------------------------------------------------------------------
class SpinOpBase:
"""Base class for spin operators."""
@classmethod
def _eval_hilbert_space(cls, label):
# We consider all j values so our space is infinite.
return ComplexSpace(S.Infinity)
@property
def name(self):
return self.args[0]
def _print_contents(self, printer, *args):
return '%s%s' % (self.name, self._coord)
def _print_contents_pretty(self, printer, *args):
a = stringPict(str(self.name))
b = stringPict(self._coord)
return self._print_subscript_pretty(a, b)
def _print_contents_latex(self, printer, *args):
return r'%s_%s' % ((self.name, self._coord))
def _represent_base(self, basis, **options):
j = options.get('j', S.Half)
size, mvals = m_values(j)
result = zeros(size, size)
for p in range(size):
for q in range(size):
me = self.matrix_element(j, mvals[p], j, mvals[q])
result[p, q] = me
return result
def _apply_op(self, ket, orig_basis, **options):
state = ket.rewrite(self.basis)
# If the state has only one term
if isinstance(state, State):
ret = (hbar*state.m)*state
# state is a linear combination of states
elif isinstance(state, Sum):
ret = self._apply_operator_Sum(state, **options)
else:
ret = qapply(self*state)
if ret == self*state:
raise NotImplementedError
return ret.rewrite(orig_basis)
def _apply_operator_JxKet(self, ket, **options):
return self._apply_op(ket, 'Jx', **options)
def _apply_operator_JxKetCoupled(self, ket, **options):
return self._apply_op(ket, 'Jx', **options)
def _apply_operator_JyKet(self, ket, **options):
return self._apply_op(ket, 'Jy', **options)
def _apply_operator_JyKetCoupled(self, ket, **options):
return self._apply_op(ket, 'Jy', **options)
def _apply_operator_JzKet(self, ket, **options):
return self._apply_op(ket, 'Jz', **options)
def _apply_operator_JzKetCoupled(self, ket, **options):
return self._apply_op(ket, 'Jz', **options)
def _apply_operator_TensorProduct(self, tp, **options):
# Uncoupling operator is only easily found for coordinate basis spin operators
# TODO: add methods for uncoupling operators
if not isinstance(self, (JxOp, JyOp, JzOp)):
raise NotImplementedError
result = []
for n in range(len(tp.args)):
arg = []
arg.extend(tp.args[:n])
arg.append(self._apply_operator(tp.args[n]))
arg.extend(tp.args[n + 1:])
result.append(tp.__class__(*arg))
return Add(*result).expand()
# TODO: move this to qapply_Mul
def _apply_operator_Sum(self, s, **options):
new_func = qapply(self*s.function)
if new_func == self*s.function:
raise NotImplementedError
return Sum(new_func, *s.limits)
def _eval_trace(self, **options):
#TODO: use options to use different j values
#For now eval at default basis
# is it efficient to represent each time
# to do a trace?
return self._represent_default_basis().trace()
class JplusOp(SpinOpBase, Operator):
"""The J+ operator."""
_coord = '+'
basis = 'Jz'
def _eval_commutator_JminusOp(self, other):
return 2*hbar*JzOp(self.name)
def _apply_operator_JzKet(self, ket, **options):
j = ket.j
m = ket.m
if m.is_Number and j.is_Number:
if m >= j:
return S.Zero
return hbar*sqrt(j*(j + S.One) - m*(m + S.One))*JzKet(j, m + S.One)
def _apply_operator_JzKetCoupled(self, ket, **options):
j = ket.j
m = ket.m
jn = ket.jn
coupling = ket.coupling
if m.is_Number and j.is_Number:
if m >= j:
return S.Zero
return hbar*sqrt(j*(j + S.One) - m*(m + S.One))*JzKetCoupled(j, m + S.One, jn, coupling)
def matrix_element(self, j, m, jp, mp):
result = hbar*sqrt(j*(j + S.One) - mp*(mp + S.One))
result *= KroneckerDelta(m, mp + 1)
result *= KroneckerDelta(j, jp)
return result
def _represent_default_basis(self, **options):
return self._represent_JzOp(None, **options)
def _represent_JzOp(self, basis, **options):
return self._represent_base(basis, **options)
def _eval_rewrite_as_xyz(self, *args, **kwargs):
return JxOp(args[0]) + I*JyOp(args[0])
class JminusOp(SpinOpBase, Operator):
"""The J- operator."""
_coord = '-'
basis = 'Jz'
def _apply_operator_JzKet(self, ket, **options):
j = ket.j
m = ket.m
if m.is_Number and j.is_Number:
if m <= -j:
return S.Zero
return hbar*sqrt(j*(j + S.One) - m*(m - S.One))*JzKet(j, m - S.One)
def _apply_operator_JzKetCoupled(self, ket, **options):
j = ket.j
m = ket.m
jn = ket.jn
coupling = ket.coupling
if m.is_Number and j.is_Number:
if m <= -j:
return S.Zero
return hbar*sqrt(j*(j + S.One) - m*(m - S.One))*JzKetCoupled(j, m - S.One, jn, coupling)
def matrix_element(self, j, m, jp, mp):
result = hbar*sqrt(j*(j + S.One) - mp*(mp - S.One))
result *= KroneckerDelta(m, mp - 1)
result *= KroneckerDelta(j, jp)
return result
def _represent_default_basis(self, **options):
return self._represent_JzOp(None, **options)
def _represent_JzOp(self, basis, **options):
return self._represent_base(basis, **options)
def _eval_rewrite_as_xyz(self, *args, **kwargs):
return JxOp(args[0]) - I*JyOp(args[0])
class JxOp(SpinOpBase, HermitianOperator):
"""The Jx operator."""
_coord = 'x'
basis = 'Jx'
def _eval_commutator_JyOp(self, other):
return I*hbar*JzOp(self.name)
def _eval_commutator_JzOp(self, other):
return -I*hbar*JyOp(self.name)
def _apply_operator_JzKet(self, ket, **options):
jp = JplusOp(self.name)._apply_operator_JzKet(ket, **options)
jm = JminusOp(self.name)._apply_operator_JzKet(ket, **options)
return (jp + jm)/Integer(2)
def _apply_operator_JzKetCoupled(self, ket, **options):
jp = JplusOp(self.name)._apply_operator_JzKetCoupled(ket, **options)
jm = JminusOp(self.name)._apply_operator_JzKetCoupled(ket, **options)
return (jp + jm)/Integer(2)
def _represent_default_basis(self, **options):
return self._represent_JzOp(None, **options)
def _represent_JzOp(self, basis, **options):
jp = JplusOp(self.name)._represent_JzOp(basis, **options)
jm = JminusOp(self.name)._represent_JzOp(basis, **options)
return (jp + jm)/Integer(2)
def _eval_rewrite_as_plusminus(self, *args, **kwargs):
return (JplusOp(args[0]) + JminusOp(args[0]))/2
class JyOp(SpinOpBase, HermitianOperator):
"""The Jy operator."""
_coord = 'y'
basis = 'Jy'
def _eval_commutator_JzOp(self, other):
return I*hbar*JxOp(self.name)
def _eval_commutator_JxOp(self, other):
return -I*hbar*J2Op(self.name)
def _apply_operator_JzKet(self, ket, **options):
jp = JplusOp(self.name)._apply_operator_JzKet(ket, **options)
jm = JminusOp(self.name)._apply_operator_JzKet(ket, **options)
return (jp - jm)/(Integer(2)*I)
def _apply_operator_JzKetCoupled(self, ket, **options):
jp = JplusOp(self.name)._apply_operator_JzKetCoupled(ket, **options)
jm = JminusOp(self.name)._apply_operator_JzKetCoupled(ket, **options)
return (jp - jm)/(Integer(2)*I)
def _represent_default_basis(self, **options):
return self._represent_JzOp(None, **options)
def _represent_JzOp(self, basis, **options):
jp = JplusOp(self.name)._represent_JzOp(basis, **options)
jm = JminusOp(self.name)._represent_JzOp(basis, **options)
return (jp - jm)/(Integer(2)*I)
def _eval_rewrite_as_plusminus(self, *args, **kwargs):
return (JplusOp(args[0]) - JminusOp(args[0]))/(2*I)
class JzOp(SpinOpBase, HermitianOperator):
"""The Jz operator."""
_coord = 'z'
basis = 'Jz'
def _eval_commutator_JxOp(self, other):
return I*hbar*JyOp(self.name)
def _eval_commutator_JyOp(self, other):
return -I*hbar*JxOp(self.name)
def _eval_commutator_JplusOp(self, other):
return hbar*JplusOp(self.name)
def _eval_commutator_JminusOp(self, other):
return -hbar*JminusOp(self.name)
def matrix_element(self, j, m, jp, mp):
result = hbar*mp
result *= KroneckerDelta(m, mp)
result *= KroneckerDelta(j, jp)
return result
def _represent_default_basis(self, **options):
return self._represent_JzOp(None, **options)
def _represent_JzOp(self, basis, **options):
return self._represent_base(basis, **options)
class J2Op(SpinOpBase, HermitianOperator):
"""The J^2 operator."""
_coord = '2'
def _eval_commutator_JxOp(self, other):
return S.Zero
def _eval_commutator_JyOp(self, other):
return S.Zero
def _eval_commutator_JzOp(self, other):
return S.Zero
def _eval_commutator_JplusOp(self, other):
return S.Zero
def _eval_commutator_JminusOp(self, other):
return S.Zero
def _apply_operator_JxKet(self, ket, **options):
j = ket.j
return hbar**2*j*(j + 1)*ket
def _apply_operator_JxKetCoupled(self, ket, **options):
j = ket.j
return hbar**2*j*(j + 1)*ket
def _apply_operator_JyKet(self, ket, **options):
j = ket.j
return hbar**2*j*(j + 1)*ket
def _apply_operator_JyKetCoupled(self, ket, **options):
j = ket.j
return hbar**2*j*(j + 1)*ket
def _apply_operator_JzKet(self, ket, **options):
j = ket.j
return hbar**2*j*(j + 1)*ket
def _apply_operator_JzKetCoupled(self, ket, **options):
j = ket.j
return hbar**2*j*(j + 1)*ket
def matrix_element(self, j, m, jp, mp):
result = (hbar**2)*j*(j + 1)
result *= KroneckerDelta(m, mp)
result *= KroneckerDelta(j, jp)
return result
def _represent_default_basis(self, **options):
return self._represent_JzOp(None, **options)
def _represent_JzOp(self, basis, **options):
return self._represent_base(basis, **options)
def _print_contents_pretty(self, printer, *args):
a = prettyForm(str(self.name))
b = prettyForm('2')
return a**b
def _print_contents_latex(self, printer, *args):
return r'%s^2' % str(self.name)
def _eval_rewrite_as_xyz(self, *args, **kwargs):
return JxOp(args[0])**2 + JyOp(args[0])**2 + JzOp(args[0])**2
def _eval_rewrite_as_plusminus(self, *args, **kwargs):
a = args[0]
return JzOp(a)**2 + \
S.Half*(JplusOp(a)*JminusOp(a) + JminusOp(a)*JplusOp(a))
class Rotation(UnitaryOperator):
"""Wigner D operator in terms of Euler angles.
Defines the rotation operator in terms of the Euler angles defined by
the z-y-z convention for a passive transformation. That is the coordinate
axes are rotated first about the z-axis, giving the new x'-y'-z' axes. Then
this new coordinate system is rotated about the new y'-axis, giving new
x''-y''-z'' axes. Then this new coordinate system is rotated about the
z''-axis. Conventions follow those laid out in [1]_.
Parameters
==========
alpha : Number, Symbol
First Euler Angle
beta : Number, Symbol
Second Euler angle
gamma : Number, Symbol
Third Euler angle
Examples
========
A simple example rotation operator:
>>> from sympy import pi
>>> from sympy.physics.quantum.spin import Rotation
>>> Rotation(pi, 0, pi/2)
R(pi,0,pi/2)
With symbolic Euler angles and calculating the inverse rotation operator:
>>> from sympy import symbols
>>> a, b, c = symbols('a b c')
>>> Rotation(a, b, c)
R(a,b,c)
>>> Rotation(a, b, c).inverse()
R(-c,-b,-a)
See Also
========
WignerD: Symbolic Wigner-D function
D: Wigner-D function
d: Wigner small-d function
References
==========
.. [1] Varshalovich, D A, Quantum Theory of Angular Momentum. 1988.
"""
@classmethod
def _eval_args(cls, args):
args = QExpr._eval_args(args)
if len(args) != 3:
raise ValueError('3 Euler angles required, got: %r' % args)
return args
@classmethod
def _eval_hilbert_space(cls, label):
# We consider all j values so our space is infinite.
return ComplexSpace(S.Infinity)
@property
def alpha(self):
return self.label[0]
@property
def beta(self):
return self.label[1]
@property
def gamma(self):
return self.label[2]
def _print_operator_name(self, printer, *args):
return 'R'
def _print_operator_name_pretty(self, printer, *args):
if printer._use_unicode:
return prettyForm('\N{SCRIPT CAPITAL R}' + ' ')
else:
return prettyForm("R ")
def _print_operator_name_latex(self, printer, *args):
return r'\mathcal{R}'
def _eval_inverse(self):
return Rotation(-self.gamma, -self.beta, -self.alpha)
@classmethod
def D(cls, j, m, mp, alpha, beta, gamma):
"""Wigner D-function.
Returns an instance of the WignerD class corresponding to the Wigner-D
function specified by the parameters.
Parameters
===========
j : Number
Total angular momentum
m : Number
Eigenvalue of angular momentum along axis after rotation
mp : Number
Eigenvalue of angular momentum along rotated axis
alpha : Number, Symbol
First Euler angle of rotation
beta : Number, Symbol
Second Euler angle of rotation
gamma : Number, Symbol
Third Euler angle of rotation
Examples
========
Return the Wigner-D matrix element for a defined rotation, both
numerical and symbolic:
>>> from sympy.physics.quantum.spin import Rotation
>>> from sympy import pi, symbols
>>> alpha, beta, gamma = symbols('alpha beta gamma')
>>> Rotation.D(1, 1, 0,pi, pi/2,-pi)
WignerD(1, 1, 0, pi, pi/2, -pi)
See Also
========
WignerD: Symbolic Wigner-D function
"""
return WignerD(j, m, mp, alpha, beta, gamma)
@classmethod
def d(cls, j, m, mp, beta):
"""Wigner small-d function.
Returns an instance of the WignerD class corresponding to the Wigner-D
function specified by the parameters with the alpha and gamma angles
given as 0.
Parameters
===========
j : Number
Total angular momentum
m : Number
Eigenvalue of angular momentum along axis after rotation
mp : Number
Eigenvalue of angular momentum along rotated axis
beta : Number, Symbol
Second Euler angle of rotation
Examples
========
Return the Wigner-D matrix element for a defined rotation, both
numerical and symbolic:
>>> from sympy.physics.quantum.spin import Rotation
>>> from sympy import pi, symbols
>>> beta = symbols('beta')
>>> Rotation.d(1, 1, 0, pi/2)
WignerD(1, 1, 0, 0, pi/2, 0)
See Also
========
WignerD: Symbolic Wigner-D function
"""
return WignerD(j, m, mp, 0, beta, 0)
def matrix_element(self, j, m, jp, mp):
result = self.__class__.D(
jp, m, mp, self.alpha, self.beta, self.gamma
)
result *= KroneckerDelta(j, jp)
return result
def _represent_base(self, basis, **options):
j = sympify(options.get('j', S.Half))
# TODO: move evaluation up to represent function/implement elsewhere
evaluate = sympify(options.get('doit'))
size, mvals = m_values(j)
result = zeros(size, size)
for p in range(size):
for q in range(size):
me = self.matrix_element(j, mvals[p], j, mvals[q])
if evaluate:
result[p, q] = me.doit()
else:
result[p, q] = me
return result
def _represent_default_basis(self, **options):
return self._represent_JzOp(None, **options)
def _represent_JzOp(self, basis, **options):
return self._represent_base(basis, **options)
def _apply_operator_uncoupled(self, state, ket, *, dummy=True, **options):
a = self.alpha
b = self.beta
g = self.gamma
j = ket.j
m = ket.m
if j.is_number:
s = []
size = m_values(j)
sz = size[1]
for mp in sz:
r = Rotation.D(j, m, mp, a, b, g)
z = r.doit()
s.append(z*state(j, mp))
return Add(*s)
else:
if dummy:
mp = Dummy('mp')
else:
mp = symbols('mp')
return Sum(Rotation.D(j, m, mp, a, b, g)*state(j, mp), (mp, -j, j))
def _apply_operator_JxKet(self, ket, **options):
return self._apply_operator_uncoupled(JxKet, ket, **options)
def _apply_operator_JyKet(self, ket, **options):
return self._apply_operator_uncoupled(JyKet, ket, **options)
def _apply_operator_JzKet(self, ket, **options):
return self._apply_operator_uncoupled(JzKet, ket, **options)
def _apply_operator_coupled(self, state, ket, *, dummy=True, **options):
a = self.alpha
b = self.beta
g = self.gamma
j = ket.j
m = ket.m
jn = ket.jn
coupling = ket.coupling
if j.is_number:
s = []
size = m_values(j)
sz = size[1]
for mp in sz:
r = Rotation.D(j, m, mp, a, b, g)
z = r.doit()
s.append(z*state(j, mp, jn, coupling))
return Add(*s)
else:
if dummy:
mp = Dummy('mp')
else:
mp = symbols('mp')
return Sum(Rotation.D(j, m, mp, a, b, g)*state(
j, mp, jn, coupling), (mp, -j, j))
def _apply_operator_JxKetCoupled(self, ket, **options):
return self._apply_operator_coupled(JxKetCoupled, ket, **options)
def _apply_operator_JyKetCoupled(self, ket, **options):
return self._apply_operator_coupled(JyKetCoupled, ket, **options)
def _apply_operator_JzKetCoupled(self, ket, **options):
return self._apply_operator_coupled(JzKetCoupled, ket, **options)
class WignerD(Expr):
r"""Wigner-D function
The Wigner D-function gives the matrix elements of the rotation
operator in the jm-representation. For the Euler angles `\alpha`,
`\beta`, `\gamma`, the D-function is defined such that:
.. math ::
<j,m| \mathcal{R}(\alpha, \beta, \gamma ) |j',m'> = \delta_{jj'} D(j, m, m', \alpha, \beta, \gamma)
Where the rotation operator is as defined by the Rotation class [1]_.
The Wigner D-function defined in this way gives:
.. math ::
D(j, m, m', \alpha, \beta, \gamma) = e^{-i m \alpha} d(j, m, m', \beta) e^{-i m' \gamma}
Where d is the Wigner small-d function, which is given by Rotation.d.
The Wigner small-d function gives the component of the Wigner
D-function that is determined by the second Euler angle. That is the
Wigner D-function is:
.. math ::
D(j, m, m', \alpha, \beta, \gamma) = e^{-i m \alpha} d(j, m, m', \beta) e^{-i m' \gamma}
Where d is the small-d function. The Wigner D-function is given by
Rotation.D.
Note that to evaluate the D-function, the j, m and mp parameters must
be integer or half integer numbers.
Parameters
==========
j : Number
Total angular momentum
m : Number
Eigenvalue of angular momentum along axis after rotation
mp : Number
Eigenvalue of angular momentum along rotated axis
alpha : Number, Symbol
First Euler angle of rotation
beta : Number, Symbol
Second Euler angle of rotation
gamma : Number, Symbol
Third Euler angle of rotation
Examples
========
Evaluate the Wigner-D matrix elements of a simple rotation:
>>> from sympy.physics.quantum.spin import Rotation
>>> from sympy import pi
>>> rot = Rotation.D(1, 1, 0, pi, pi/2, 0)
>>> rot
WignerD(1, 1, 0, pi, pi/2, 0)
>>> rot.doit()
sqrt(2)/2
Evaluate the Wigner-d matrix elements of a simple rotation
>>> rot = Rotation.d(1, 1, 0, pi/2)
>>> rot
WignerD(1, 1, 0, 0, pi/2, 0)
>>> rot.doit()
-sqrt(2)/2
See Also
========
Rotation: Rotation operator
References
==========
.. [1] Varshalovich, D A, Quantum Theory of Angular Momentum. 1988.
"""
is_commutative = True
def __new__(cls, *args, **hints):
if not len(args) == 6:
raise ValueError('6 parameters expected, got %s' % args)
args = sympify(args)
evaluate = hints.get('evaluate', False)
if evaluate:
return Expr.__new__(cls, *args)._eval_wignerd()
return Expr.__new__(cls, *args)
@property
def j(self):
return self.args[0]
@property
def m(self):
return self.args[1]
@property
def mp(self):
return self.args[2]
@property
def alpha(self):
return self.args[3]
@property
def beta(self):
return self.args[4]
@property
def gamma(self):
return self.args[5]
def _latex(self, printer, *args):
if self.alpha == 0 and self.gamma == 0:
return r'd^{%s}_{%s,%s}\left(%s\right)' % \
(
printer._print(self.j), printer._print(
self.m), printer._print(self.mp),
printer._print(self.beta) )
return r'D^{%s}_{%s,%s}\left(%s,%s,%s\right)' % \
(
printer._print(
self.j), printer._print(self.m), printer._print(self.mp),
printer._print(self.alpha), printer._print(self.beta), printer._print(self.gamma) )
def _pretty(self, printer, *args):
top = printer._print(self.j)
bot = printer._print(self.m)
bot = prettyForm(*bot.right(','))
bot = prettyForm(*bot.right(printer._print(self.mp)))
pad = max(top.width(), bot.width())
top = prettyForm(*top.left(' '))
bot = prettyForm(*bot.left(' '))
if pad > top.width():
top = prettyForm(*top.right(' '*(pad - top.width())))
if pad > bot.width():
bot = prettyForm(*bot.right(' '*(pad - bot.width())))
if self.alpha == 0 and self.gamma == 0:
args = printer._print(self.beta)
s = stringPict('d' + ' '*pad)
else:
args = printer._print(self.alpha)
args = prettyForm(*args.right(','))
args = prettyForm(*args.right(printer._print(self.beta)))
args = prettyForm(*args.right(','))
args = prettyForm(*args.right(printer._print(self.gamma)))
s = stringPict('D' + ' '*pad)
args = prettyForm(*args.parens())
s = prettyForm(*s.above(top))
s = prettyForm(*s.below(bot))
s = prettyForm(*s.right(args))
return s
def doit(self, **hints):
hints['evaluate'] = True
return WignerD(*self.args, **hints)
def _eval_wignerd(self):
j = self.j
m = self.m
mp = self.mp
alpha = self.alpha
beta = self.beta
gamma = self.gamma
if alpha == 0 and beta == 0 and gamma == 0:
return KroneckerDelta(m, mp)
if not j.is_number:
raise ValueError(
'j parameter must be numerical to evaluate, got %s' % j)
r = 0
if beta == pi/2:
# Varshalovich Equation (5), Section 4.16, page 113, setting
# alpha=gamma=0.
for k in range(2*j + 1):
if k > j + mp or k > j - m or k < mp - m:
continue
r += (S.NegativeOne)**k*binomial(j + mp, k)*binomial(j - mp, k + m - mp)
r *= (S.NegativeOne)**(m - mp) / 2**j*sqrt(factorial(j + m) *
factorial(j - m) / (factorial(j + mp)*factorial(j - mp)))
else:
# Varshalovich Equation(5), Section 4.7.2, page 87, where we set
# beta1=beta2=pi/2, and we get alpha=gamma=pi/2 and beta=phi+pi,
# then we use the Eq. (1), Section 4.4. page 79, to simplify:
# d(j, m, mp, beta+pi) = (-1)**(j-mp)*d(j, m, -mp, beta)
# This happens to be almost the same as in Eq.(10), Section 4.16,
# except that we need to substitute -mp for mp.
size, mvals = m_values(j)
for mpp in mvals:
r += Rotation.d(j, m, mpp, pi/2).doit()*(cos(-mpp*beta) + I*sin(-mpp*beta))*\
Rotation.d(j, mpp, -mp, pi/2).doit()
# Empirical normalization factor so results match Varshalovich
# Tables 4.3-4.12
# Note that this exact normalization does not follow from the
# above equations
r = r*I**(2*j - m - mp)*(-1)**(2*m)
# Finally, simplify the whole expression
r = simplify(r)
r *= exp(-I*m*alpha)*exp(-I*mp*gamma)
return r
Jx = JxOp('J')
Jy = JyOp('J')
Jz = JzOp('J')
J2 = J2Op('J')
Jplus = JplusOp('J')
Jminus = JminusOp('J')
#-----------------------------------------------------------------------------
# Spin States
#-----------------------------------------------------------------------------
class SpinState(State):
"""Base class for angular momentum states."""
_label_separator = ','
def __new__(cls, j, m):
j = sympify(j)
m = sympify(m)
if j.is_number:
if 2*j != int(2*j):
raise ValueError(
'j must be integer or half-integer, got: %s' % j)
if j < 0:
raise ValueError('j must be >= 0, got: %s' % j)
if m.is_number:
if 2*m != int(2*m):
raise ValueError(
'm must be integer or half-integer, got: %s' % m)
if j.is_number and m.is_number:
if abs(m) > j:
raise ValueError('Allowed values for m are -j <= m <= j, got j, m: %s, %s' % (j, m))
if int(j - m) != j - m:
raise ValueError('Both j and m must be integer or half-integer, got j, m: %s, %s' % (j, m))
return State.__new__(cls, j, m)
@property
def j(self):
return self.label[0]
@property
def m(self):
return self.label[1]
@classmethod
def _eval_hilbert_space(cls, label):
return ComplexSpace(2*label[0] + 1)
def _represent_base(self, **options):
j = self.j
m = self.m
alpha = sympify(options.get('alpha', 0))
beta = sympify(options.get('beta', 0))
gamma = sympify(options.get('gamma', 0))
size, mvals = m_values(j)
result = zeros(size, 1)
# breaks finding angles on L930
for p, mval in enumerate(mvals):
if m.is_number:
result[p, 0] = Rotation.D(
self.j, mval, self.m, alpha, beta, gamma).doit()
else:
result[p, 0] = Rotation.D(self.j, mval,
self.m, alpha, beta, gamma)
return result
def _eval_rewrite_as_Jx(self, *args, **options):
if isinstance(self, Bra):
return self._rewrite_basis(Jx, JxBra, **options)
return self._rewrite_basis(Jx, JxKet, **options)
def _eval_rewrite_as_Jy(self, *args, **options):
if isinstance(self, Bra):
return self._rewrite_basis(Jy, JyBra, **options)
return self._rewrite_basis(Jy, JyKet, **options)
def _eval_rewrite_as_Jz(self, *args, **options):
if isinstance(self, Bra):
return self._rewrite_basis(Jz, JzBra, **options)
return self._rewrite_basis(Jz, JzKet, **options)
def _rewrite_basis(self, basis, evect, **options):
from sympy.physics.quantum.represent import represent
j = self.j
args = self.args[2:]
if j.is_number:
if isinstance(self, CoupledSpinState):
if j == int(j):
start = j**2
else:
start = (2*j - 1)*(2*j + 1)/4
else:
start = 0
vect = represent(self, basis=basis, **options)
result = Add(
*[vect[start + i]*evect(j, j - i, *args) for i in range(2*j + 1)])
if isinstance(self, CoupledSpinState) and options.get('coupled') is False:
return uncouple(result)
return result
else:
i = 0
mi = symbols('mi')
# make sure not to introduce a symbol already in the state
while self.subs(mi, 0) != self:
i += 1
mi = symbols('mi%d' % i)
break
# TODO: better way to get angles of rotation
if isinstance(self, CoupledSpinState):
test_args = (0, mi, (0, 0))
else:
test_args = (0, mi)
if isinstance(self, Ket):
angles = represent(
self.__class__(*test_args), basis=basis)[0].args[3:6]
else:
angles = represent(self.__class__(
*test_args), basis=basis)[0].args[0].args[3:6]
if angles == (0, 0, 0):
return self
else:
state = evect(j, mi, *args)
lt = Rotation.D(j, mi, self.m, *angles)
return Sum(lt*state, (mi, -j, j))
def _eval_innerproduct_JxBra(self, bra, **hints):
result = KroneckerDelta(self.j, bra.j)
if bra.dual_class() is not self.__class__:
result *= self._represent_JxOp(None)[bra.j - bra.m]
else:
result *= KroneckerDelta(
self.j, bra.j)*KroneckerDelta(self.m, bra.m)
return result
def _eval_innerproduct_JyBra(self, bra, **hints):
result = KroneckerDelta(self.j, bra.j)
if bra.dual_class() is not self.__class__:
result *= self._represent_JyOp(None)[bra.j - bra.m]
else:
result *= KroneckerDelta(
self.j, bra.j)*KroneckerDelta(self.m, bra.m)
return result
def _eval_innerproduct_JzBra(self, bra, **hints):
result = KroneckerDelta(self.j, bra.j)
if bra.dual_class() is not self.__class__:
result *= self._represent_JzOp(None)[bra.j - bra.m]
else:
result *= KroneckerDelta(
self.j, bra.j)*KroneckerDelta(self.m, bra.m)
return result
def _eval_trace(self, bra, **hints):
# One way to implement this method is to assume the basis set k is
# passed.
# Then we can apply the discrete form of Trace formula here
# Tr(|i><j| ) = \Sum_k <k|i><j|k>
#then we do qapply() on each each inner product and sum over them.
# OR
# Inner product of |i><j| = Trace(Outer Product).
# we could just use this unless there are cases when this is not true
return (bra*self).doit()
class JxKet(SpinState, Ket):
"""Eigenket of Jx.
See JzKet for the usage of spin eigenstates.
See Also
========
JzKet: Usage of spin states
"""
@classmethod
def dual_class(self):
return JxBra
@classmethod
def coupled_class(self):
return JxKetCoupled
def _represent_default_basis(self, **options):
return self._represent_JxOp(None, **options)
def _represent_JxOp(self, basis, **options):
return self._represent_base(**options)
def _represent_JyOp(self, basis, **options):
return self._represent_base(alpha=pi*Rational(3, 2), **options)
def _represent_JzOp(self, basis, **options):
return self._represent_base(beta=pi/2, **options)
class JxBra(SpinState, Bra):
"""Eigenbra of Jx.
See JzKet for the usage of spin eigenstates.
See Also
========
JzKet: Usage of spin states
"""
@classmethod
def dual_class(self):
return JxKet
@classmethod
def coupled_class(self):
return JxBraCoupled
class JyKet(SpinState, Ket):
"""Eigenket of Jy.
See JzKet for the usage of spin eigenstates.
See Also
========
JzKet: Usage of spin states
"""
@classmethod
def dual_class(self):
return JyBra
@classmethod
def coupled_class(self):
return JyKetCoupled
def _represent_default_basis(self, **options):
return self._represent_JyOp(None, **options)
def _represent_JxOp(self, basis, **options):
return self._represent_base(gamma=pi/2, **options)
def _represent_JyOp(self, basis, **options):
return self._represent_base(**options)
def _represent_JzOp(self, basis, **options):
return self._represent_base(alpha=pi*Rational(3, 2), beta=-pi/2, gamma=pi/2, **options)
class JyBra(SpinState, Bra):
"""Eigenbra of Jy.
See JzKet for the usage of spin eigenstates.
See Also
========
JzKet: Usage of spin states
"""
@classmethod
def dual_class(self):
return JyKet
@classmethod
def coupled_class(self):
return JyBraCoupled
class JzKet(SpinState, Ket):
"""Eigenket of Jz.
Spin state which is an eigenstate of the Jz operator. Uncoupled states,
that is states representing the interaction of multiple separate spin
states, are defined as a tensor product of states.
Parameters
==========
j : Number, Symbol
Total spin angular momentum
m : Number, Symbol
Eigenvalue of the Jz spin operator
Examples
========
*Normal States:*
Defining simple spin states, both numerical and symbolic:
>>> from sympy.physics.quantum.spin import JzKet, JxKet
>>> from sympy import symbols
>>> JzKet(1, 0)
|1,0>
>>> j, m = symbols('j m')
>>> JzKet(j, m)
|j,m>
Rewriting the JzKet in terms of eigenkets of the Jx operator:
Note: that the resulting eigenstates are JxKet's
>>> JzKet(1,1).rewrite("Jx")
|1,-1>/2 - sqrt(2)*|1,0>/2 + |1,1>/2
Get the vector representation of a state in terms of the basis elements
of the Jx operator:
>>> from sympy.physics.quantum.represent import represent
>>> from sympy.physics.quantum.spin import Jx, Jz
>>> represent(JzKet(1,-1), basis=Jx)
Matrix([
[ 1/2],
[sqrt(2)/2],
[ 1/2]])
Apply innerproducts between states:
>>> from sympy.physics.quantum.innerproduct import InnerProduct
>>> from sympy.physics.quantum.spin import JxBra
>>> i = InnerProduct(JxBra(1,1), JzKet(1,1))
>>> i
<1,1|1,1>
>>> i.doit()
1/2
*Uncoupled States:*
Define an uncoupled state as a TensorProduct between two Jz eigenkets:
>>> from sympy.physics.quantum.tensorproduct import TensorProduct
>>> j1,m1,j2,m2 = symbols('j1 m1 j2 m2')
>>> TensorProduct(JzKet(1,0), JzKet(1,1))
|1,0>x|1,1>
>>> TensorProduct(JzKet(j1,m1), JzKet(j2,m2))
|j1,m1>x|j2,m2>
A TensorProduct can be rewritten, in which case the eigenstates that make
up the tensor product is rewritten to the new basis:
>>> TensorProduct(JzKet(1,1),JxKet(1,1)).rewrite('Jz')
|1,1>x|1,-1>/2 + sqrt(2)*|1,1>x|1,0>/2 + |1,1>x|1,1>/2
The represent method for TensorProduct's gives the vector representation of
the state. Note that the state in the product basis is the equivalent of the
tensor product of the vector representation of the component eigenstates:
>>> represent(TensorProduct(JzKet(1,0),JzKet(1,1)))
Matrix([
[0],
[0],
[0],
[1],
[0],
[0],
[0],
[0],
[0]])
>>> represent(TensorProduct(JzKet(1,1),JxKet(1,1)), basis=Jz)
Matrix([
[ 1/2],
[sqrt(2)/2],
[ 1/2],
[ 0],
[ 0],
[ 0],
[ 0],
[ 0],
[ 0]])
See Also
========
JzKetCoupled: Coupled eigenstates
sympy.physics.quantum.tensorproduct.TensorProduct: Used to specify uncoupled states
uncouple: Uncouples states given coupling parameters
couple: Couples uncoupled states
"""
@classmethod
def dual_class(self):
return JzBra
@classmethod
def coupled_class(self):
return JzKetCoupled
def _represent_default_basis(self, **options):
return self._represent_JzOp(None, **options)
def _represent_JxOp(self, basis, **options):
return self._represent_base(beta=pi*Rational(3, 2), **options)
def _represent_JyOp(self, basis, **options):
return self._represent_base(alpha=pi*Rational(3, 2), beta=pi/2, gamma=pi/2, **options)
def _represent_JzOp(self, basis, **options):
return self._represent_base(**options)
class JzBra(SpinState, Bra):
"""Eigenbra of Jz.
See the JzKet for the usage of spin eigenstates.
See Also
========
JzKet: Usage of spin states
"""
@classmethod
def dual_class(self):
return JzKet
@classmethod
def coupled_class(self):
return JzBraCoupled
# Method used primarily to create coupled_n and coupled_jn by __new__ in
# CoupledSpinState
# This same method is also used by the uncouple method, and is separated from
# the CoupledSpinState class to maintain consistency in defining coupling
def _build_coupled(jcoupling, length):
n_list = [ [n + 1] for n in range(length) ]
coupled_jn = []
coupled_n = []
for n1, n2, j_new in jcoupling:
coupled_jn.append(j_new)
coupled_n.append( (n_list[n1 - 1], n_list[n2 - 1]) )
n_sort = sorted(n_list[n1 - 1] + n_list[n2 - 1])
n_list[n_sort[0] - 1] = n_sort
return coupled_n, coupled_jn
class CoupledSpinState(SpinState):
"""Base class for coupled angular momentum states."""
def __new__(cls, j, m, jn, *jcoupling):
# Check j and m values using SpinState
SpinState(j, m)
# Build and check coupling scheme from arguments
if len(jcoupling) == 0:
# Use default coupling scheme
jcoupling = []
for n in range(2, len(jn)):
jcoupling.append( (1, n, Add(*[jn[i] for i in range(n)])) )
jcoupling.append( (1, len(jn), j) )
elif len(jcoupling) == 1:
# Use specified coupling scheme
jcoupling = jcoupling[0]
else:
raise TypeError("CoupledSpinState only takes 3 or 4 arguments, got: %s" % (len(jcoupling) + 3) )
# Check arguments have correct form
if not isinstance(jn, (list, tuple, Tuple)):
raise TypeError('jn must be Tuple, list or tuple, got %s' %
jn.__class__.__name__)
if not isinstance(jcoupling, (list, tuple, Tuple)):
raise TypeError('jcoupling must be Tuple, list or tuple, got %s' %
jcoupling.__class__.__name__)
if not all(isinstance(term, (list, tuple, Tuple)) for term in jcoupling):
raise TypeError(
'All elements of jcoupling must be list, tuple or Tuple')
if not len(jn) - 1 == len(jcoupling):
raise ValueError('jcoupling must have length of %d, got %d' %
(len(jn) - 1, len(jcoupling)))
if not all(len(x) == 3 for x in jcoupling):
raise ValueError('All elements of jcoupling must have length 3')
# Build sympified args
j = sympify(j)
m = sympify(m)
jn = Tuple( *[sympify(ji) for ji in jn] )
jcoupling = Tuple( *[Tuple(sympify(
n1), sympify(n2), sympify(ji)) for (n1, n2, ji) in jcoupling] )
# Check values in coupling scheme give physical state
if any(2*ji != int(2*ji) for ji in jn if ji.is_number):
raise ValueError('All elements of jn must be integer or half-integer, got: %s' % jn)
if any(n1 != int(n1) or n2 != int(n2) for (n1, n2, _) in jcoupling):
raise ValueError('Indices in jcoupling must be integers')
if any(n1 < 1 or n2 < 1 or n1 > len(jn) or n2 > len(jn) for (n1, n2, _) in jcoupling):
raise ValueError('Indices must be between 1 and the number of coupled spin spaces')
if any(2*ji != int(2*ji) for (_, _, ji) in jcoupling if ji.is_number):
raise ValueError('All coupled j values in coupling scheme must be integer or half-integer')
coupled_n, coupled_jn = _build_coupled(jcoupling, len(jn))
jvals = list(jn)
for n, (n1, n2) in enumerate(coupled_n):
j1 = jvals[min(n1) - 1]
j2 = jvals[min(n2) - 1]
j3 = coupled_jn[n]
if sympify(j1).is_number and sympify(j2).is_number and sympify(j3).is_number:
if j1 + j2 < j3:
raise ValueError('All couplings must have j1+j2 >= j3, '
'in coupling number %d got j1,j2,j3: %d,%d,%d' % (n + 1, j1, j2, j3))
if abs(j1 - j2) > j3:
raise ValueError("All couplings must have |j1+j2| <= j3, "
"in coupling number %d got j1,j2,j3: %d,%d,%d" % (n + 1, j1, j2, j3))
if int_valued(j1 + j2):
pass
jvals[min(n1 + n2) - 1] = j3
if len(jcoupling) > 0 and jcoupling[-1][2] != j:
raise ValueError('Last j value coupled together must be the final j of the state')
# Return state
return State.__new__(cls, j, m, jn, jcoupling)
def _print_label(self, printer, *args):
label = [printer._print(self.j), printer._print(self.m)]
for i, ji in enumerate(self.jn, start=1):
label.append('j%d=%s' % (
i, printer._print(ji)
))
for jn, (n1, n2) in zip(self.coupled_jn[:-1], self.coupled_n[:-1]):
label.append('j(%s)=%s' % (
','.join(str(i) for i in sorted(n1 + n2)), printer._print(jn)
))
return ','.join(label)
def _print_label_pretty(self, printer, *args):
label = [self.j, self.m]
for i, ji in enumerate(self.jn, start=1):
symb = 'j%d' % i
symb = pretty_symbol(symb)
symb = prettyForm(symb + '=')
item = prettyForm(*symb.right(printer._print(ji)))
label.append(item)
for jn, (n1, n2) in zip(self.coupled_jn[:-1], self.coupled_n[:-1]):
n = ','.join(pretty_symbol("j%d" % i)[-1] for i in sorted(n1 + n2))
symb = prettyForm('j' + n + '=')
item = prettyForm(*symb.right(printer._print(jn)))
label.append(item)
return self._print_sequence_pretty(
label, self._label_separator, printer, *args
)
def _print_label_latex(self, printer, *args):
label = [
printer._print(self.j, *args),
printer._print(self.m, *args)
]
for i, ji in enumerate(self.jn, start=1):
label.append('j_{%d}=%s' % (i, printer._print(ji, *args)) )
for jn, (n1, n2) in zip(self.coupled_jn[:-1], self.coupled_n[:-1]):
n = ','.join(str(i) for i in sorted(n1 + n2))
label.append('j_{%s}=%s' % (n, printer._print(jn, *args)) )
return self._label_separator.join(label)
@property
def jn(self):
return self.label[2]
@property
def coupling(self):
return self.label[3]
@property
def coupled_jn(self):
return _build_coupled(self.label[3], len(self.label[2]))[1]
@property
def coupled_n(self):
return _build_coupled(self.label[3], len(self.label[2]))[0]
@classmethod
def _eval_hilbert_space(cls, label):
j = Add(*label[2])
if j.is_number:
return DirectSumHilbertSpace(*[ ComplexSpace(x) for x in range(int(2*j + 1), 0, -2) ])
else:
# TODO: Need hilbert space fix, see issue 5732
# Desired behavior:
#ji = symbols('ji')
#ret = Sum(ComplexSpace(2*ji + 1), (ji, 0, j))
# Temporary fix:
return ComplexSpace(2*j + 1)
def _represent_coupled_base(self, **options):
evect = self.uncoupled_class()
if not self.j.is_number:
raise ValueError(
'State must not have symbolic j value to represent')
if not self.hilbert_space.dimension.is_number:
raise ValueError(
'State must not have symbolic j values to represent')
result = zeros(self.hilbert_space.dimension, 1)
if self.j == int(self.j):
start = self.j**2
else:
start = (2*self.j - 1)*(1 + 2*self.j)/4
result[start:start + 2*self.j + 1, 0] = evect(
self.j, self.m)._represent_base(**options)
return result
def _eval_rewrite_as_Jx(self, *args, **options):
if isinstance(self, Bra):
return self._rewrite_basis(Jx, JxBraCoupled, **options)
return self._rewrite_basis(Jx, JxKetCoupled, **options)
def _eval_rewrite_as_Jy(self, *args, **options):
if isinstance(self, Bra):
return self._rewrite_basis(Jy, JyBraCoupled, **options)
return self._rewrite_basis(Jy, JyKetCoupled, **options)
def _eval_rewrite_as_Jz(self, *args, **options):
if isinstance(self, Bra):
return self._rewrite_basis(Jz, JzBraCoupled, **options)
return self._rewrite_basis(Jz, JzKetCoupled, **options)
class JxKetCoupled(CoupledSpinState, Ket):
"""Coupled eigenket of Jx.
See JzKetCoupled for the usage of coupled spin eigenstates.
See Also
========
JzKetCoupled: Usage of coupled spin states
"""
@classmethod
def dual_class(self):
return JxBraCoupled
@classmethod
def uncoupled_class(self):
return JxKet
def _represent_default_basis(self, **options):
return self._represent_JzOp(None, **options)
def _represent_JxOp(self, basis, **options):
return self._represent_coupled_base(**options)
def _represent_JyOp(self, basis, **options):
return self._represent_coupled_base(alpha=pi*Rational(3, 2), **options)
def _represent_JzOp(self, basis, **options):
return self._represent_coupled_base(beta=pi/2, **options)
class JxBraCoupled(CoupledSpinState, Bra):
"""Coupled eigenbra of Jx.
See JzKetCoupled for the usage of coupled spin eigenstates.
See Also
========
JzKetCoupled: Usage of coupled spin states
"""
@classmethod
def dual_class(self):
return JxKetCoupled
@classmethod
def uncoupled_class(self):
return JxBra
class JyKetCoupled(CoupledSpinState, Ket):
"""Coupled eigenket of Jy.
See JzKetCoupled for the usage of coupled spin eigenstates.
See Also
========
JzKetCoupled: Usage of coupled spin states
"""
@classmethod
def dual_class(self):
return JyBraCoupled
@classmethod
def uncoupled_class(self):
return JyKet
def _represent_default_basis(self, **options):
return self._represent_JzOp(None, **options)
def _represent_JxOp(self, basis, **options):
return self._represent_coupled_base(gamma=pi/2, **options)
def _represent_JyOp(self, basis, **options):
return self._represent_coupled_base(**options)
def _represent_JzOp(self, basis, **options):
return self._represent_coupled_base(alpha=pi*Rational(3, 2), beta=-pi/2, gamma=pi/2, **options)
class JyBraCoupled(CoupledSpinState, Bra):
"""Coupled eigenbra of Jy.
See JzKetCoupled for the usage of coupled spin eigenstates.
See Also
========
JzKetCoupled: Usage of coupled spin states
"""
@classmethod
def dual_class(self):
return JyKetCoupled
@classmethod
def uncoupled_class(self):
return JyBra
class JzKetCoupled(CoupledSpinState, Ket):
r"""Coupled eigenket of Jz
Spin state that is an eigenket of Jz which represents the coupling of
separate spin spaces.
The arguments for creating instances of JzKetCoupled are ``j``, ``m``,
``jn`` and an optional ``jcoupling`` argument. The ``j`` and ``m`` options
are the total angular momentum quantum numbers, as used for normal states
(e.g. JzKet).
The other required parameter in ``jn``, which is a tuple defining the `j_n`
angular momentum quantum numbers of the product spaces. So for example, if
a state represented the coupling of the product basis state
`\left|j_1,m_1\right\rangle\times\left|j_2,m_2\right\rangle`, the ``jn``
for this state would be ``(j1,j2)``.
The final option is ``jcoupling``, which is used to define how the spaces
specified by ``jn`` are coupled, which includes both the order these spaces
are coupled together and the quantum numbers that arise from these
couplings. The ``jcoupling`` parameter itself is a list of lists, such that
each of the sublists defines a single coupling between the spin spaces. If
there are N coupled angular momentum spaces, that is ``jn`` has N elements,
then there must be N-1 sublists. Each of these sublists making up the
``jcoupling`` parameter have length 3. The first two elements are the
indices of the product spaces that are considered to be coupled together.
For example, if we want to couple `j_1` and `j_4`, the indices would be 1
and 4. If a state has already been coupled, it is referenced by the
smallest index that is coupled, so if `j_2` and `j_4` has already been
coupled to some `j_{24}`, then this value can be coupled by referencing it
with index 2. The final element of the sublist is the quantum number of the
coupled state. So putting everything together, into a valid sublist for
``jcoupling``, if `j_1` and `j_2` are coupled to an angular momentum space
with quantum number `j_{12}` with the value ``j12``, the sublist would be
``(1,2,j12)``, N-1 of these sublists are used in the list for
``jcoupling``.
Note the ``jcoupling`` parameter is optional, if it is not specified, the
default coupling is taken. This default value is to coupled the spaces in
order and take the quantum number of the coupling to be the maximum value.
For example, if the spin spaces are `j_1`, `j_2`, `j_3`, `j_4`, then the
default coupling couples `j_1` and `j_2` to `j_{12}=j_1+j_2`, then,
`j_{12}` and `j_3` are coupled to `j_{123}=j_{12}+j_3`, and finally
`j_{123}` and `j_4` to `j=j_{123}+j_4`. The jcoupling value that would
correspond to this is:
``((1,2,j1+j2),(1,3,j1+j2+j3))``
Parameters
==========
args : tuple
The arguments that must be passed are ``j``, ``m``, ``jn``, and
``jcoupling``. The ``j`` value is the total angular momentum. The ``m``
value is the eigenvalue of the Jz spin operator. The ``jn`` list are
the j values of argular momentum spaces coupled together. The
``jcoupling`` parameter is an optional parameter defining how the spaces
are coupled together. See the above description for how these coupling
parameters are defined.
Examples
========
Defining simple spin states, both numerical and symbolic:
>>> from sympy.physics.quantum.spin import JzKetCoupled
>>> from sympy import symbols
>>> JzKetCoupled(1, 0, (1, 1))
|1,0,j1=1,j2=1>
>>> j, m, j1, j2 = symbols('j m j1 j2')
>>> JzKetCoupled(j, m, (j1, j2))
|j,m,j1=j1,j2=j2>
Defining coupled spin states for more than 2 coupled spaces with various
coupling parameters:
>>> JzKetCoupled(2, 1, (1, 1, 1))
|2,1,j1=1,j2=1,j3=1,j(1,2)=2>
>>> JzKetCoupled(2, 1, (1, 1, 1), ((1,2,2),(1,3,2)) )
|2,1,j1=1,j2=1,j3=1,j(1,2)=2>
>>> JzKetCoupled(2, 1, (1, 1, 1), ((2,3,1),(1,2,2)) )
|2,1,j1=1,j2=1,j3=1,j(2,3)=1>
Rewriting the JzKetCoupled in terms of eigenkets of the Jx operator:
Note: that the resulting eigenstates are JxKetCoupled
>>> JzKetCoupled(1,1,(1,1)).rewrite("Jx")
|1,-1,j1=1,j2=1>/2 - sqrt(2)*|1,0,j1=1,j2=1>/2 + |1,1,j1=1,j2=1>/2
The rewrite method can be used to convert a coupled state to an uncoupled
state. This is done by passing coupled=False to the rewrite function:
>>> JzKetCoupled(1, 0, (1, 1)).rewrite('Jz', coupled=False)
-sqrt(2)*|1,-1>x|1,1>/2 + sqrt(2)*|1,1>x|1,-1>/2
Get the vector representation of a state in terms of the basis elements
of the Jx operator:
>>> from sympy.physics.quantum.represent import represent
>>> from sympy.physics.quantum.spin import Jx
>>> from sympy import S
>>> represent(JzKetCoupled(1,-1,(S(1)/2,S(1)/2)), basis=Jx)
Matrix([
[ 0],
[ 1/2],
[sqrt(2)/2],
[ 1/2]])
See Also
========
JzKet: Normal spin eigenstates
uncouple: Uncoupling of coupling spin states
couple: Coupling of uncoupled spin states
"""
@classmethod
def dual_class(self):
return JzBraCoupled
@classmethod
def uncoupled_class(self):
return JzKet
def _represent_default_basis(self, **options):
return self._represent_JzOp(None, **options)
def _represent_JxOp(self, basis, **options):
return self._represent_coupled_base(beta=pi*Rational(3, 2), **options)
def _represent_JyOp(self, basis, **options):
return self._represent_coupled_base(alpha=pi*Rational(3, 2), beta=pi/2, gamma=pi/2, **options)
def _represent_JzOp(self, basis, **options):
return self._represent_coupled_base(**options)
class JzBraCoupled(CoupledSpinState, Bra):
"""Coupled eigenbra of Jz.
See the JzKetCoupled for the usage of coupled spin eigenstates.
See Also
========
JzKetCoupled: Usage of coupled spin states
"""
@classmethod
def dual_class(self):
return JzKetCoupled
@classmethod
def uncoupled_class(self):
return JzBra
#-----------------------------------------------------------------------------
# Coupling/uncoupling
#-----------------------------------------------------------------------------
def couple(expr, jcoupling_list=None):
""" Couple a tensor product of spin states
This function can be used to couple an uncoupled tensor product of spin
states. All of the eigenstates to be coupled must be of the same class. It
will return a linear combination of eigenstates that are subclasses of
CoupledSpinState determined by Clebsch-Gordan angular momentum coupling
coefficients.
Parameters
==========
expr : Expr
An expression involving TensorProducts of spin states to be coupled.
Each state must be a subclass of SpinState and they all must be the
same class.
jcoupling_list : list or tuple
Elements of this list are sub-lists of length 2 specifying the order of
the coupling of the spin spaces. The length of this must be N-1, where N
is the number of states in the tensor product to be coupled. The
elements of this sublist are the same as the first two elements of each
sublist in the ``jcoupling`` parameter defined for JzKetCoupled. If this
parameter is not specified, the default value is taken, which couples
the first and second product basis spaces, then couples this new coupled
space to the third product space, etc
Examples
========
Couple a tensor product of numerical states for two spaces:
>>> from sympy.physics.quantum.spin import JzKet, couple
>>> from sympy.physics.quantum.tensorproduct import TensorProduct
>>> couple(TensorProduct(JzKet(1,0), JzKet(1,1)))
-sqrt(2)*|1,1,j1=1,j2=1>/2 + sqrt(2)*|2,1,j1=1,j2=1>/2
Numerical coupling of three spaces using the default coupling method, i.e.
first and second spaces couple, then this couples to the third space:
>>> couple(TensorProduct(JzKet(1,1), JzKet(1,1), JzKet(1,0)))
sqrt(6)*|2,2,j1=1,j2=1,j3=1,j(1,2)=2>/3 + sqrt(3)*|3,2,j1=1,j2=1,j3=1,j(1,2)=2>/3
Perform this same coupling, but we define the coupling to first couple
the first and third spaces:
>>> couple(TensorProduct(JzKet(1,1), JzKet(1,1), JzKet(1,0)), ((1,3),(1,2)) )
sqrt(2)*|2,2,j1=1,j2=1,j3=1,j(1,3)=1>/2 - sqrt(6)*|2,2,j1=1,j2=1,j3=1,j(1,3)=2>/6 + sqrt(3)*|3,2,j1=1,j2=1,j3=1,j(1,3)=2>/3
Couple a tensor product of symbolic states:
>>> from sympy import symbols
>>> j1,m1,j2,m2 = symbols('j1 m1 j2 m2')
>>> couple(TensorProduct(JzKet(j1,m1), JzKet(j2,m2)))
Sum(CG(j1, m1, j2, m2, j, m1 + m2)*|j,m1 + m2,j1=j1,j2=j2>, (j, m1 + m2, j1 + j2))
"""
a = expr.atoms(TensorProduct)
for tp in a:
# Allow other tensor products to be in expression
if not all(isinstance(state, SpinState) for state in tp.args):
continue
# If tensor product has all spin states, raise error for invalid tensor product state
if not all(state.__class__ is tp.args[0].__class__ for state in tp.args):
raise TypeError('All states must be the same basis')
expr = expr.subs(tp, _couple(tp, jcoupling_list))
return expr
def _couple(tp, jcoupling_list):
states = tp.args
coupled_evect = states[0].coupled_class()
# Define default coupling if none is specified
if jcoupling_list is None:
jcoupling_list = []
for n in range(1, len(states)):
jcoupling_list.append( (1, n + 1) )
# Check jcoupling_list valid
if not len(jcoupling_list) == len(states) - 1:
raise TypeError('jcoupling_list must be length %d, got %d' %
(len(states) - 1, len(jcoupling_list)))
if not all( len(coupling) == 2 for coupling in jcoupling_list):
raise ValueError('Each coupling must define 2 spaces')
if any(n1 == n2 for n1, n2 in jcoupling_list):
raise ValueError('Spin spaces cannot couple to themselves')
if all(sympify(n1).is_number and sympify(n2).is_number for n1, n2 in jcoupling_list):
j_test = [0]*len(states)
for n1, n2 in jcoupling_list:
if j_test[n1 - 1] == -1 or j_test[n2 - 1] == -1:
raise ValueError('Spaces coupling j_n\'s are referenced by smallest n value')
j_test[max(n1, n2) - 1] = -1
# j values of states to be coupled together
jn = [state.j for state in states]
mn = [state.m for state in states]
# Create coupling_list, which defines all the couplings between all
# the spaces from jcoupling_list
coupling_list = []
n_list = [ [i + 1] for i in range(len(states)) ]
for j_coupling in jcoupling_list:
# Least n for all j_n which is coupled as first and second spaces
n1, n2 = j_coupling
# List of all n's coupled in first and second spaces
j1_n = list(n_list[n1 - 1])
j2_n = list(n_list[n2 - 1])
coupling_list.append( (j1_n, j2_n) )
# Set new j_n to be coupling of all j_n in both first and second spaces
n_list[ min(n1, n2) - 1 ] = sorted(j1_n + j2_n)
if all(state.j.is_number and state.m.is_number for state in states):
# Numerical coupling
# Iterate over difference between maximum possible j value of each coupling and the actual value
diff_max = [ Add( *[ jn[n - 1] - mn[n - 1] for n in coupling[0] +
coupling[1] ] ) for coupling in coupling_list ]
result = []
for diff in range(diff_max[-1] + 1):
# Determine available configurations
n = len(coupling_list)
tot = binomial(diff + n - 1, diff)
for config_num in range(tot):
diff_list = _confignum_to_difflist(config_num, diff, n)
# Skip the configuration if non-physical
# This is a lazy check for physical states given the loose restrictions of diff_max
if any(d > m for d, m in zip(diff_list, diff_max)):
continue
# Determine term
cg_terms = []
coupled_j = list(jn)
jcoupling = []
for (j1_n, j2_n), coupling_diff in zip(coupling_list, diff_list):
j1 = coupled_j[ min(j1_n) - 1 ]
j2 = coupled_j[ min(j2_n) - 1 ]
j3 = j1 + j2 - coupling_diff
coupled_j[ min(j1_n + j2_n) - 1 ] = j3
m1 = Add( *[ mn[x - 1] for x in j1_n] )
m2 = Add( *[ mn[x - 1] for x in j2_n] )
m3 = m1 + m2
cg_terms.append( (j1, m1, j2, m2, j3, m3) )
jcoupling.append( (min(j1_n), min(j2_n), j3) )
# Better checks that state is physical
if any(abs(term[5]) > term[4] for term in cg_terms):
continue
if any(term[0] + term[2] < term[4] for term in cg_terms):
continue
if any(abs(term[0] - term[2]) > term[4] for term in cg_terms):
continue
coeff = Mul( *[ CG(*term).doit() for term in cg_terms] )
state = coupled_evect(j3, m3, jn, jcoupling)
result.append(coeff*state)
return Add(*result)
else:
# Symbolic coupling
cg_terms = []
jcoupling = []
sum_terms = []
coupled_j = list(jn)
for j1_n, j2_n in coupling_list:
j1 = coupled_j[ min(j1_n) - 1 ]
j2 = coupled_j[ min(j2_n) - 1 ]
if len(j1_n + j2_n) == len(states):
j3 = symbols('j')
else:
j3_name = 'j' + ''.join(["%s" % n for n in j1_n + j2_n])
j3 = symbols(j3_name)
coupled_j[ min(j1_n + j2_n) - 1 ] = j3
m1 = Add( *[ mn[x - 1] for x in j1_n] )
m2 = Add( *[ mn[x - 1] for x in j2_n] )
m3 = m1 + m2
cg_terms.append( (j1, m1, j2, m2, j3, m3) )
jcoupling.append( (min(j1_n), min(j2_n), j3) )
sum_terms.append((j3, m3, j1 + j2))
coeff = Mul( *[ CG(*term) for term in cg_terms] )
state = coupled_evect(j3, m3, jn, jcoupling)
return Sum(coeff*state, *sum_terms)
def uncouple(expr, jn=None, jcoupling_list=None):
""" Uncouple a coupled spin state
Gives the uncoupled representation of a coupled spin state. Arguments must
be either a spin state that is a subclass of CoupledSpinState or a spin
state that is a subclass of SpinState and an array giving the j values
of the spaces that are to be coupled
Parameters
==========
expr : Expr
The expression containing states that are to be coupled. If the states
are a subclass of SpinState, the ``jn`` and ``jcoupling`` parameters
must be defined. If the states are a subclass of CoupledSpinState,
``jn`` and ``jcoupling`` will be taken from the state.
jn : list or tuple
The list of the j-values that are coupled. If state is a
CoupledSpinState, this parameter is ignored. This must be defined if
state is not a subclass of CoupledSpinState. The syntax of this
parameter is the same as the ``jn`` parameter of JzKetCoupled.
jcoupling_list : list or tuple
The list defining how the j-values are coupled together. If state is a
CoupledSpinState, this parameter is ignored. This must be defined if
state is not a subclass of CoupledSpinState. The syntax of this
parameter is the same as the ``jcoupling`` parameter of JzKetCoupled.
Examples
========
Uncouple a numerical state using a CoupledSpinState state:
>>> from sympy.physics.quantum.spin import JzKetCoupled, uncouple
>>> from sympy import S
>>> uncouple(JzKetCoupled(1, 0, (S(1)/2, S(1)/2)))
sqrt(2)*|1/2,-1/2>x|1/2,1/2>/2 + sqrt(2)*|1/2,1/2>x|1/2,-1/2>/2
Perform the same calculation using a SpinState state:
>>> from sympy.physics.quantum.spin import JzKet
>>> uncouple(JzKet(1, 0), (S(1)/2, S(1)/2))
sqrt(2)*|1/2,-1/2>x|1/2,1/2>/2 + sqrt(2)*|1/2,1/2>x|1/2,-1/2>/2
Uncouple a numerical state of three coupled spaces using a CoupledSpinState state:
>>> uncouple(JzKetCoupled(1, 1, (1, 1, 1), ((1,3,1),(1,2,1)) ))
|1,-1>x|1,1>x|1,1>/2 - |1,0>x|1,0>x|1,1>/2 + |1,1>x|1,0>x|1,0>/2 - |1,1>x|1,1>x|1,-1>/2
Perform the same calculation using a SpinState state:
>>> uncouple(JzKet(1, 1), (1, 1, 1), ((1,3,1),(1,2,1)) )
|1,-1>x|1,1>x|1,1>/2 - |1,0>x|1,0>x|1,1>/2 + |1,1>x|1,0>x|1,0>/2 - |1,1>x|1,1>x|1,-1>/2
Uncouple a symbolic state using a CoupledSpinState state:
>>> from sympy import symbols
>>> j,m,j1,j2 = symbols('j m j1 j2')
>>> uncouple(JzKetCoupled(j, m, (j1, j2)))
Sum(CG(j1, m1, j2, m2, j, m)*|j1,m1>x|j2,m2>, (m1, -j1, j1), (m2, -j2, j2))
Perform the same calculation using a SpinState state
>>> uncouple(JzKet(j, m), (j1, j2))
Sum(CG(j1, m1, j2, m2, j, m)*|j1,m1>x|j2,m2>, (m1, -j1, j1), (m2, -j2, j2))
"""
a = expr.atoms(SpinState)
for state in a:
expr = expr.subs(state, _uncouple(state, jn, jcoupling_list))
return expr
def _uncouple(state, jn, jcoupling_list):
if isinstance(state, CoupledSpinState):
jn = state.jn
coupled_n = state.coupled_n
coupled_jn = state.coupled_jn
evect = state.uncoupled_class()
elif isinstance(state, SpinState):
if jn is None:
raise ValueError("Must specify j-values for coupled state")
if not isinstance(jn, (list, tuple)):
raise TypeError("jn must be list or tuple")
if jcoupling_list is None:
# Use default
jcoupling_list = []
for i in range(1, len(jn)):
jcoupling_list.append(
(1, 1 + i, Add(*[jn[j] for j in range(i + 1)])) )
if not isinstance(jcoupling_list, (list, tuple)):
raise TypeError("jcoupling must be a list or tuple")
if not len(jcoupling_list) == len(jn) - 1:
raise ValueError("Must specify 2 fewer coupling terms than the number of j values")
coupled_n, coupled_jn = _build_coupled(jcoupling_list, len(jn))
evect = state.__class__
else:
raise TypeError("state must be a spin state")
j = state.j
m = state.m
coupling_list = []
j_list = list(jn)
# Create coupling, which defines all the couplings between all the spaces
for j3, (n1, n2) in zip(coupled_jn, coupled_n):
# j's which are coupled as first and second spaces
j1 = j_list[n1[0] - 1]
j2 = j_list[n2[0] - 1]
# Build coupling list
coupling_list.append( (n1, n2, j1, j2, j3) )
# Set new value in j_list
j_list[min(n1 + n2) - 1] = j3
if j.is_number and m.is_number:
diff_max = [ 2*x for x in jn ]
diff = Add(*jn) - m
n = len(jn)
tot = binomial(diff + n - 1, diff)
result = []
for config_num in range(tot):
diff_list = _confignum_to_difflist(config_num, diff, n)
if any(d > p for d, p in zip(diff_list, diff_max)):
continue
cg_terms = []
for coupling in coupling_list:
j1_n, j2_n, j1, j2, j3 = coupling
m1 = Add( *[ jn[x - 1] - diff_list[x - 1] for x in j1_n ] )
m2 = Add( *[ jn[x - 1] - diff_list[x - 1] for x in j2_n ] )
m3 = m1 + m2
cg_terms.append( (j1, m1, j2, m2, j3, m3) )
coeff = Mul( *[ CG(*term).doit() for term in cg_terms ] )
state = TensorProduct(
*[ evect(j, j - d) for j, d in zip(jn, diff_list) ] )
result.append(coeff*state)
return Add(*result)
else:
# Symbolic coupling
m_str = "m1:%d" % (len(jn) + 1)
mvals = symbols(m_str)
cg_terms = [(j1, Add(*[mvals[n - 1] for n in j1_n]),
j2, Add(*[mvals[n - 1] for n in j2_n]),
j3, Add(*[mvals[n - 1] for n in j1_n + j2_n])) for j1_n, j2_n, j1, j2, j3 in coupling_list[:-1] ]
cg_terms.append(*[(j1, Add(*[mvals[n - 1] for n in j1_n]),
j2, Add(*[mvals[n - 1] for n in j2_n]),
j, m) for j1_n, j2_n, j1, j2, j3 in [coupling_list[-1]] ])
cg_coeff = Mul(*[CG(*cg_term) for cg_term in cg_terms])
sum_terms = [ (m, -j, j) for j, m in zip(jn, mvals) ]
state = TensorProduct( *[ evect(j, m) for j, m in zip(jn, mvals) ] )
return Sum(cg_coeff*state, *sum_terms)
def _confignum_to_difflist(config_num, diff, list_len):
# Determines configuration of diffs into list_len number of slots
diff_list = []
for n in range(list_len):
prev_diff = diff
# Number of spots after current one
rem_spots = list_len - n - 1
# Number of configurations of distributing diff among the remaining spots
rem_configs = binomial(diff + rem_spots - 1, diff)
while config_num >= rem_configs:
config_num -= rem_configs
diff -= 1
rem_configs = binomial(diff + rem_spots - 1, diff)
diff_list.append(prev_diff - diff)
return diff_list
PK ]ZZZ��l�By By sympy/physics/quantum/state.py"""Dirac notation for states."""
from sympy.core.cache import cacheit
from sympy.core.containers import Tuple
from sympy.core.expr import Expr
from sympy.core.function import Function
from sympy.core.numbers import oo, equal_valued
from sympy.core.singleton import S
from sympy.functions.elementary.complexes import conjugate
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.integrals.integrals import integrate
from sympy.printing.pretty.stringpict import stringPict
from sympy.physics.quantum.qexpr import QExpr, dispatch_method
__all__ = [
'KetBase',
'BraBase',
'StateBase',
'State',
'Ket',
'Bra',
'TimeDepState',
'TimeDepBra',
'TimeDepKet',
'OrthogonalKet',
'OrthogonalBra',
'OrthogonalState',
'Wavefunction'
]
#-----------------------------------------------------------------------------
# States, bras and kets.
#-----------------------------------------------------------------------------
# ASCII brackets
_lbracket = "<"
_rbracket = ">"
_straight_bracket = "|"
# Unicode brackets
# MATHEMATICAL ANGLE BRACKETS
_lbracket_ucode = "\N{MATHEMATICAL LEFT ANGLE BRACKET}"
_rbracket_ucode = "\N{MATHEMATICAL RIGHT ANGLE BRACKET}"
# LIGHT VERTICAL BAR
_straight_bracket_ucode = "\N{LIGHT VERTICAL BAR}"
# Other options for unicode printing of <, > and | for Dirac notation.
# LEFT-POINTING ANGLE BRACKET
# _lbracket = "\u2329"
# _rbracket = "\u232A"
# LEFT ANGLE BRACKET
# _lbracket = "\u3008"
# _rbracket = "\u3009"
# VERTICAL LINE
# _straight_bracket = "\u007C"
class StateBase(QExpr):
"""Abstract base class for general abstract states in quantum mechanics.
All other state classes defined will need to inherit from this class. It
carries the basic structure for all other states such as dual, _eval_adjoint
and label.
This is an abstract base class and you should not instantiate it directly,
instead use State.
"""
@classmethod
def _operators_to_state(self, ops, **options):
""" Returns the eigenstate instance for the passed operators.
This method should be overridden in subclasses. It will handle being
passed either an Operator instance or set of Operator instances. It
should return the corresponding state INSTANCE or simply raise a
NotImplementedError. See cartesian.py for an example.
"""
raise NotImplementedError("Cannot map operators to states in this class. Method not implemented!")
def _state_to_operators(self, op_classes, **options):
""" Returns the operators which this state instance is an eigenstate
of.
This method should be overridden in subclasses. It will be called on
state instances and be passed the operator classes that we wish to make
into instances. The state instance will then transform the classes
appropriately, or raise a NotImplementedError if it cannot return
operator instances. See cartesian.py for examples,
"""
raise NotImplementedError(
"Cannot map this state to operators. Method not implemented!")
@property
def operators(self):
"""Return the operator(s) that this state is an eigenstate of"""
from .operatorset import state_to_operators # import internally to avoid circular import errors
return state_to_operators(self)
def _enumerate_state(self, num_states, **options):
raise NotImplementedError("Cannot enumerate this state!")
def _represent_default_basis(self, **options):
return self._represent(basis=self.operators)
def _apply_operator(self, op, **options):
return None
#-------------------------------------------------------------------------
# Dagger/dual
#-------------------------------------------------------------------------
@property
def dual(self):
"""Return the dual state of this one."""
return self.dual_class()._new_rawargs(self.hilbert_space, *self.args)
@classmethod
def dual_class(self):
"""Return the class used to construct the dual."""
raise NotImplementedError(
'dual_class must be implemented in a subclass'
)
def _eval_adjoint(self):
"""Compute the dagger of this state using the dual."""
return self.dual
#-------------------------------------------------------------------------
# Printing
#-------------------------------------------------------------------------
def _pretty_brackets(self, height, use_unicode=True):
# Return pretty printed brackets for the state
# Ideally, this could be done by pform.parens but it does not support the angled < and >
# Setup for unicode vs ascii
if use_unicode:
lbracket, rbracket = getattr(self, 'lbracket_ucode', ""), getattr(self, 'rbracket_ucode', "")
slash, bslash, vert = '\N{BOX DRAWINGS LIGHT DIAGONAL UPPER RIGHT TO LOWER LEFT}', \
'\N{BOX DRAWINGS LIGHT DIAGONAL UPPER LEFT TO LOWER RIGHT}', \
'\N{BOX DRAWINGS LIGHT VERTICAL}'
else:
lbracket, rbracket = getattr(self, 'lbracket', ""), getattr(self, 'rbracket', "")
slash, bslash, vert = '/', '\\', '|'
# If height is 1, just return brackets
if height == 1:
return stringPict(lbracket), stringPict(rbracket)
# Make height even
height += (height % 2)
brackets = []
for bracket in lbracket, rbracket:
# Create left bracket
if bracket in {_lbracket, _lbracket_ucode}:
bracket_args = [ ' ' * (height//2 - i - 1) +
slash for i in range(height // 2)]
bracket_args.extend(
[' ' * i + bslash for i in range(height // 2)])
# Create right bracket
elif bracket in {_rbracket, _rbracket_ucode}:
bracket_args = [ ' ' * i + bslash for i in range(height // 2)]
bracket_args.extend([ ' ' * (
height//2 - i - 1) + slash for i in range(height // 2)])
# Create straight bracket
elif bracket in {_straight_bracket, _straight_bracket_ucode}:
bracket_args = [vert] * height
else:
raise ValueError(bracket)
brackets.append(
stringPict('\n'.join(bracket_args), baseline=height//2))
return brackets
def _sympystr(self, printer, *args):
contents = self._print_contents(printer, *args)
return '%s%s%s' % (getattr(self, 'lbracket', ""), contents, getattr(self, 'rbracket', ""))
def _pretty(self, printer, *args):
from sympy.printing.pretty.stringpict import prettyForm
# Get brackets
pform = self._print_contents_pretty(printer, *args)
lbracket, rbracket = self._pretty_brackets(
pform.height(), printer._use_unicode)
# Put together state
pform = prettyForm(*pform.left(lbracket))
pform = prettyForm(*pform.right(rbracket))
return pform
def _latex(self, printer, *args):
contents = self._print_contents_latex(printer, *args)
# The extra {} brackets are needed to get matplotlib's latex
# rendered to render this properly.
return '{%s%s%s}' % (getattr(self, 'lbracket_latex', ""), contents, getattr(self, 'rbracket_latex', ""))
class KetBase(StateBase):
"""Base class for Kets.
This class defines the dual property and the brackets for printing. This is
an abstract base class and you should not instantiate it directly, instead
use Ket.
"""
lbracket = _straight_bracket
rbracket = _rbracket
lbracket_ucode = _straight_bracket_ucode
rbracket_ucode = _rbracket_ucode
lbracket_latex = r'\left|'
rbracket_latex = r'\right\rangle '
@classmethod
def default_args(self):
return ("psi",)
@classmethod
def dual_class(self):
return BraBase
def __mul__(self, other):
"""KetBase*other"""
from sympy.physics.quantum.operator import OuterProduct
if isinstance(other, BraBase):
return OuterProduct(self, other)
else:
return Expr.__mul__(self, other)
def __rmul__(self, other):
"""other*KetBase"""
from sympy.physics.quantum.innerproduct import InnerProduct
if isinstance(other, BraBase):
return InnerProduct(other, self)
else:
return Expr.__rmul__(self, other)
#-------------------------------------------------------------------------
# _eval_* methods
#-------------------------------------------------------------------------
def _eval_innerproduct(self, bra, **hints):
"""Evaluate the inner product between this ket and a bra.
This is called to compute <bra|ket>, where the ket is ``self``.
This method will dispatch to sub-methods having the format::
``def _eval_innerproduct_BraClass(self, **hints):``
Subclasses should define these methods (one for each BraClass) to
teach the ket how to take inner products with bras.
"""
return dispatch_method(self, '_eval_innerproduct', bra, **hints)
def _apply_from_right_to(self, op, **options):
"""Apply an Operator to this Ket as Operator*Ket
This method will dispatch to methods having the format::
``def _apply_from_right_to_OperatorName(op, **options):``
Subclasses should define these methods (one for each OperatorName) to
teach the Ket how to implement OperatorName*Ket
Parameters
==========
op : Operator
The Operator that is acting on the Ket as op*Ket
options : dict
A dict of key/value pairs that control how the operator is applied
to the Ket.
"""
return dispatch_method(self, '_apply_from_right_to', op, **options)
class BraBase(StateBase):
"""Base class for Bras.
This class defines the dual property and the brackets for printing. This
is an abstract base class and you should not instantiate it directly,
instead use Bra.
"""
lbracket = _lbracket
rbracket = _straight_bracket
lbracket_ucode = _lbracket_ucode
rbracket_ucode = _straight_bracket_ucode
lbracket_latex = r'\left\langle '
rbracket_latex = r'\right|'
@classmethod
def _operators_to_state(self, ops, **options):
state = self.dual_class()._operators_to_state(ops, **options)
return state.dual
def _state_to_operators(self, op_classes, **options):
return self.dual._state_to_operators(op_classes, **options)
def _enumerate_state(self, num_states, **options):
dual_states = self.dual._enumerate_state(num_states, **options)
return [x.dual for x in dual_states]
@classmethod
def default_args(self):
return self.dual_class().default_args()
@classmethod
def dual_class(self):
return KetBase
def __mul__(self, other):
"""BraBase*other"""
from sympy.physics.quantum.innerproduct import InnerProduct
if isinstance(other, KetBase):
return InnerProduct(self, other)
else:
return Expr.__mul__(self, other)
def __rmul__(self, other):
"""other*BraBase"""
from sympy.physics.quantum.operator import OuterProduct
if isinstance(other, KetBase):
return OuterProduct(other, self)
else:
return Expr.__rmul__(self, other)
def _represent(self, **options):
"""A default represent that uses the Ket's version."""
from sympy.physics.quantum.dagger import Dagger
return Dagger(self.dual._represent(**options))
class State(StateBase):
"""General abstract quantum state used as a base class for Ket and Bra."""
pass
class Ket(State, KetBase):
"""A general time-independent Ket in quantum mechanics.
Inherits from State and KetBase. This class should be used as the base
class for all physical, time-independent Kets in a system. This class
and its subclasses will be the main classes that users will use for
expressing Kets in Dirac notation [1]_.
Parameters
==========
args : tuple
The list of numbers or parameters that uniquely specify the
ket. This will usually be its symbol or its quantum numbers. For
time-dependent state, this will include the time.
Examples
========
Create a simple Ket and looking at its properties::
>>> from sympy.physics.quantum import Ket
>>> from sympy import symbols, I
>>> k = Ket('psi')
>>> k
|psi>
>>> k.hilbert_space
H
>>> k.is_commutative
False
>>> k.label
(psi,)
Ket's know about their associated bra::
>>> k.dual
<psi|
>>> k.dual_class()
<class 'sympy.physics.quantum.state.Bra'>
Take a linear combination of two kets::
>>> k0 = Ket(0)
>>> k1 = Ket(1)
>>> 2*I*k0 - 4*k1
2*I*|0> - 4*|1>
Compound labels are passed as tuples::
>>> n, m = symbols('n,m')
>>> k = Ket(n,m)
>>> k
|nm>
References
==========
.. [1] https://en.wikipedia.org/wiki/Bra-ket_notation
"""
@classmethod
def dual_class(self):
return Bra
class Bra(State, BraBase):
"""A general time-independent Bra in quantum mechanics.
Inherits from State and BraBase. A Bra is the dual of a Ket [1]_. This
class and its subclasses will be the main classes that users will use for
expressing Bras in Dirac notation.
Parameters
==========
args : tuple
The list of numbers or parameters that uniquely specify the
ket. This will usually be its symbol or its quantum numbers. For
time-dependent state, this will include the time.
Examples
========
Create a simple Bra and look at its properties::
>>> from sympy.physics.quantum import Bra
>>> from sympy import symbols, I
>>> b = Bra('psi')
>>> b
<psi|
>>> b.hilbert_space
H
>>> b.is_commutative
False
Bra's know about their dual Ket's::
>>> b.dual
|psi>
>>> b.dual_class()
<class 'sympy.physics.quantum.state.Ket'>
Like Kets, Bras can have compound labels and be manipulated in a similar
manner::
>>> n, m = symbols('n,m')
>>> b = Bra(n,m) - I*Bra(m,n)
>>> b
-I*<mn| + <nm|
Symbols in a Bra can be substituted using ``.subs``::
>>> b.subs(n,m)
<mm| - I*<mm|
References
==========
.. [1] https://en.wikipedia.org/wiki/Bra-ket_notation
"""
@classmethod
def dual_class(self):
return Ket
#-----------------------------------------------------------------------------
# Time dependent states, bras and kets.
#-----------------------------------------------------------------------------
class TimeDepState(StateBase):
"""Base class for a general time-dependent quantum state.
This class is used as a base class for any time-dependent state. The main
difference between this class and the time-independent state is that this
class takes a second argument that is the time in addition to the usual
label argument.
Parameters
==========
args : tuple
The list of numbers or parameters that uniquely specify the ket. This
will usually be its symbol or its quantum numbers. For time-dependent
state, this will include the time as the final argument.
"""
#-------------------------------------------------------------------------
# Initialization
#-------------------------------------------------------------------------
@classmethod
def default_args(self):
return ("psi", "t")
#-------------------------------------------------------------------------
# Properties
#-------------------------------------------------------------------------
@property
def label(self):
"""The label of the state."""
return self.args[:-1]
@property
def time(self):
"""The time of the state."""
return self.args[-1]
#-------------------------------------------------------------------------
# Printing
#-------------------------------------------------------------------------
def _print_time(self, printer, *args):
return printer._print(self.time, *args)
_print_time_repr = _print_time
_print_time_latex = _print_time
def _print_time_pretty(self, printer, *args):
pform = printer._print(self.time, *args)
return pform
def _print_contents(self, printer, *args):
label = self._print_label(printer, *args)
time = self._print_time(printer, *args)
return '%s;%s' % (label, time)
def _print_label_repr(self, printer, *args):
label = self._print_sequence(self.label, ',', printer, *args)
time = self._print_time_repr(printer, *args)
return '%s,%s' % (label, time)
def _print_contents_pretty(self, printer, *args):
label = self._print_label_pretty(printer, *args)
time = self._print_time_pretty(printer, *args)
return printer._print_seq((label, time), delimiter=';')
def _print_contents_latex(self, printer, *args):
label = self._print_sequence(
self.label, self._label_separator, printer, *args)
time = self._print_time_latex(printer, *args)
return '%s;%s' % (label, time)
class TimeDepKet(TimeDepState, KetBase):
"""General time-dependent Ket in quantum mechanics.
This inherits from ``TimeDepState`` and ``KetBase`` and is the main class
that should be used for Kets that vary with time. Its dual is a
``TimeDepBra``.
Parameters
==========
args : tuple
The list of numbers or parameters that uniquely specify the ket. This
will usually be its symbol or its quantum numbers. For time-dependent
state, this will include the time as the final argument.
Examples
========
Create a TimeDepKet and look at its attributes::
>>> from sympy.physics.quantum import TimeDepKet
>>> k = TimeDepKet('psi', 't')
>>> k
|psi;t>
>>> k.time
t
>>> k.label
(psi,)
>>> k.hilbert_space
H
TimeDepKets know about their dual bra::
>>> k.dual
<psi;t|
>>> k.dual_class()
<class 'sympy.physics.quantum.state.TimeDepBra'>
"""
@classmethod
def dual_class(self):
return TimeDepBra
class TimeDepBra(TimeDepState, BraBase):
"""General time-dependent Bra in quantum mechanics.
This inherits from TimeDepState and BraBase and is the main class that
should be used for Bras that vary with time. Its dual is a TimeDepBra.
Parameters
==========
args : tuple
The list of numbers or parameters that uniquely specify the ket. This
will usually be its symbol or its quantum numbers. For time-dependent
state, this will include the time as the final argument.
Examples
========
>>> from sympy.physics.quantum import TimeDepBra
>>> b = TimeDepBra('psi', 't')
>>> b
<psi;t|
>>> b.time
t
>>> b.label
(psi,)
>>> b.hilbert_space
H
>>> b.dual
|psi;t>
"""
@classmethod
def dual_class(self):
return TimeDepKet
class OrthogonalState(State, StateBase):
"""General abstract quantum state used as a base class for Ket and Bra."""
pass
class OrthogonalKet(OrthogonalState, KetBase):
"""Orthogonal Ket in quantum mechanics.
The inner product of two states with different labels will give zero,
states with the same label will give one.
>>> from sympy.physics.quantum import OrthogonalBra, OrthogonalKet
>>> from sympy.abc import m, n
>>> (OrthogonalBra(n)*OrthogonalKet(n)).doit()
1
>>> (OrthogonalBra(n)*OrthogonalKet(n+1)).doit()
0
>>> (OrthogonalBra(n)*OrthogonalKet(m)).doit()
<n|m>
"""
@classmethod
def dual_class(self):
return OrthogonalBra
def _eval_innerproduct(self, bra, **hints):
if len(self.args) != len(bra.args):
raise ValueError('Cannot multiply a ket that has a different number of labels.')
for arg, bra_arg in zip(self.args, bra.args):
diff = arg - bra_arg
diff = diff.expand()
is_zero = diff.is_zero
if is_zero is False:
return S.Zero # i.e. Integer(0)
if is_zero is None:
return None
return S.One # i.e. Integer(1)
class OrthogonalBra(OrthogonalState, BraBase):
"""Orthogonal Bra in quantum mechanics.
"""
@classmethod
def dual_class(self):
return OrthogonalKet
class Wavefunction(Function):
"""Class for representations in continuous bases
This class takes an expression and coordinates in its constructor. It can
be used to easily calculate normalizations and probabilities.
Parameters
==========
expr : Expr
The expression representing the functional form of the w.f.
coords : Symbol or tuple
The coordinates to be integrated over, and their bounds
Examples
========
Particle in a box, specifying bounds in the more primitive way of using
Piecewise:
>>> from sympy import Symbol, Piecewise, pi, N
>>> from sympy.functions import sqrt, sin
>>> from sympy.physics.quantum.state import Wavefunction
>>> x = Symbol('x', real=True)
>>> n = 1
>>> L = 1
>>> g = Piecewise((0, x < 0), (0, x > L), (sqrt(2//L)*sin(n*pi*x/L), True))
>>> f = Wavefunction(g, x)
>>> f.norm
1
>>> f.is_normalized
True
>>> p = f.prob()
>>> p(0)
0
>>> p(L)
0
>>> p(0.5)
2
>>> p(0.85*L)
2*sin(0.85*pi)**2
>>> N(p(0.85*L))
0.412214747707527
Additionally, you can specify the bounds of the function and the indices in
a more compact way:
>>> from sympy import symbols, pi, diff
>>> from sympy.functions import sqrt, sin
>>> from sympy.physics.quantum.state import Wavefunction
>>> x, L = symbols('x,L', positive=True)
>>> n = symbols('n', integer=True, positive=True)
>>> g = sqrt(2/L)*sin(n*pi*x/L)
>>> f = Wavefunction(g, (x, 0, L))
>>> f.norm
1
>>> f(L+1)
0
>>> f(L-1)
sqrt(2)*sin(pi*n*(L - 1)/L)/sqrt(L)
>>> f(-1)
0
>>> f(0.85)
sqrt(2)*sin(0.85*pi*n/L)/sqrt(L)
>>> f(0.85, n=1, L=1)
sqrt(2)*sin(0.85*pi)
>>> f.is_commutative
False
All arguments are automatically sympified, so you can define the variables
as strings rather than symbols:
>>> expr = x**2
>>> f = Wavefunction(expr, 'x')
>>> type(f.variables[0])
<class 'sympy.core.symbol.Symbol'>
Derivatives of Wavefunctions will return Wavefunctions:
>>> diff(f, x)
Wavefunction(2*x, x)
"""
#Any passed tuples for coordinates and their bounds need to be
#converted to Tuples before Function's constructor is called, to
#avoid errors from calling is_Float in the constructor
def __new__(cls, *args, **options):
new_args = [None for i in args]
ct = 0
for arg in args:
if isinstance(arg, tuple):
new_args[ct] = Tuple(*arg)
else:
new_args[ct] = arg
ct += 1
return super().__new__(cls, *new_args, **options)
def __call__(self, *args, **options):
var = self.variables
if len(args) != len(var):
raise NotImplementedError(
"Incorrect number of arguments to function!")
ct = 0
#If the passed value is outside the specified bounds, return 0
for v in var:
lower, upper = self.limits[v]
#Do the comparison to limits only if the passed symbol is actually
#a symbol present in the limits;
#Had problems with a comparison of x > L
if isinstance(args[ct], Expr) and \
not (lower in args[ct].free_symbols
or upper in args[ct].free_symbols):
continue
if (args[ct] < lower) == True or (args[ct] > upper) == True:
return S.Zero
ct += 1
expr = self.expr
#Allows user to make a call like f(2, 4, m=1, n=1)
for symbol in list(expr.free_symbols):
if str(symbol) in options.keys():
val = options[str(symbol)]
expr = expr.subs(symbol, val)
return expr.subs(zip(var, args))
def _eval_derivative(self, symbol):
expr = self.expr
deriv = expr._eval_derivative(symbol)
return Wavefunction(deriv, *self.args[1:])
def _eval_conjugate(self):
return Wavefunction(conjugate(self.expr), *self.args[1:])
def _eval_transpose(self):
return self
@property
def free_symbols(self):
return self.expr.free_symbols
@property
def is_commutative(self):
"""
Override Function's is_commutative so that order is preserved in
represented expressions
"""
return False
@classmethod
def eval(self, *args):
return None
@property
def variables(self):
"""
Return the coordinates which the wavefunction depends on
Examples
========
>>> from sympy.physics.quantum.state import Wavefunction
>>> from sympy import symbols
>>> x,y = symbols('x,y')
>>> f = Wavefunction(x*y, x, y)
>>> f.variables
(x, y)
>>> g = Wavefunction(x*y, x)
>>> g.variables
(x,)
"""
var = [g[0] if isinstance(g, Tuple) else g for g in self._args[1:]]
return tuple(var)
@property
def limits(self):
"""
Return the limits of the coordinates which the w.f. depends on If no
limits are specified, defaults to ``(-oo, oo)``.
Examples
========
>>> from sympy.physics.quantum.state import Wavefunction
>>> from sympy import symbols
>>> x, y = symbols('x, y')
>>> f = Wavefunction(x**2, (x, 0, 1))
>>> f.limits
{x: (0, 1)}
>>> f = Wavefunction(x**2, x)
>>> f.limits
{x: (-oo, oo)}
>>> f = Wavefunction(x**2 + y**2, x, (y, -1, 2))
>>> f.limits
{x: (-oo, oo), y: (-1, 2)}
"""
limits = [(g[1], g[2]) if isinstance(g, Tuple) else (-oo, oo)
for g in self._args[1:]]
return dict(zip(self.variables, tuple(limits)))
@property
def expr(self):
"""
Return the expression which is the functional form of the Wavefunction
Examples
========
>>> from sympy.physics.quantum.state import Wavefunction
>>> from sympy import symbols
>>> x, y = symbols('x, y')
>>> f = Wavefunction(x**2, x)
>>> f.expr
x**2
"""
return self._args[0]
@property
def is_normalized(self):
"""
Returns true if the Wavefunction is properly normalized
Examples
========
>>> from sympy import symbols, pi
>>> from sympy.functions import sqrt, sin
>>> from sympy.physics.quantum.state import Wavefunction
>>> x, L = symbols('x,L', positive=True)
>>> n = symbols('n', integer=True, positive=True)
>>> g = sqrt(2/L)*sin(n*pi*x/L)
>>> f = Wavefunction(g, (x, 0, L))
>>> f.is_normalized
True
"""
return equal_valued(self.norm, 1)
@property # type: ignore
@cacheit
def norm(self):
"""
Return the normalization of the specified functional form.
This function integrates over the coordinates of the Wavefunction, with
the bounds specified.
Examples
========
>>> from sympy import symbols, pi
>>> from sympy.functions import sqrt, sin
>>> from sympy.physics.quantum.state import Wavefunction
>>> x, L = symbols('x,L', positive=True)
>>> n = symbols('n', integer=True, positive=True)
>>> g = sqrt(2/L)*sin(n*pi*x/L)
>>> f = Wavefunction(g, (x, 0, L))
>>> f.norm
1
>>> g = sin(n*pi*x/L)
>>> f = Wavefunction(g, (x, 0, L))
>>> f.norm
sqrt(2)*sqrt(L)/2
"""
exp = self.expr*conjugate(self.expr)
var = self.variables
limits = self.limits
for v in var:
curr_limits = limits[v]
exp = integrate(exp, (v, curr_limits[0], curr_limits[1]))
return sqrt(exp)
def normalize(self):
"""
Return a normalized version of the Wavefunction
Examples
========
>>> from sympy import symbols, pi
>>> from sympy.functions import sin
>>> from sympy.physics.quantum.state import Wavefunction
>>> x = symbols('x', real=True)
>>> L = symbols('L', positive=True)
>>> n = symbols('n', integer=True, positive=True)
>>> g = sin(n*pi*x/L)
>>> f = Wavefunction(g, (x, 0, L))
>>> f.normalize()
Wavefunction(sqrt(2)*sin(pi*n*x/L)/sqrt(L), (x, 0, L))
"""
const = self.norm
if const is oo:
raise NotImplementedError("The function is not normalizable!")
else:
return Wavefunction((const)**(-1)*self.expr, *self.args[1:])
def prob(self):
r"""
Return the absolute magnitude of the w.f., `|\psi(x)|^2`
Examples
========
>>> from sympy import symbols, pi
>>> from sympy.functions import sin
>>> from sympy.physics.quantum.state import Wavefunction
>>> x, L = symbols('x,L', real=True)
>>> n = symbols('n', integer=True)
>>> g = sin(n*pi*x/L)
>>> f = Wavefunction(g, (x, 0, L))
>>> f.prob()
Wavefunction(sin(pi*n*x/L)**2, x)
"""
return Wavefunction(self.expr*conjugate(self.expr), *self.variables)
PK ]ZZZQ�J+�: �: & sympy/physics/quantum/tensorproduct.py"""Abstract tensor product."""
from sympy.core.add import Add
from sympy.core.expr import Expr
from sympy.core.mul import Mul
from sympy.core.power import Pow
from sympy.core.sympify import sympify
from sympy.matrices.dense import DenseMatrix as Matrix
from sympy.matrices.immutable import ImmutableDenseMatrix as ImmutableMatrix
from sympy.printing.pretty.stringpict import prettyForm
from sympy.physics.quantum.qexpr import QuantumError
from sympy.physics.quantum.dagger import Dagger
from sympy.physics.quantum.commutator import Commutator
from sympy.physics.quantum.anticommutator import AntiCommutator
from sympy.physics.quantum.state import Ket, Bra
from sympy.physics.quantum.matrixutils import (
numpy_ndarray,
scipy_sparse_matrix,
matrix_tensor_product
)
from sympy.physics.quantum.trace import Tr
__all__ = [
'TensorProduct',
'tensor_product_simp'
]
#-----------------------------------------------------------------------------
# Tensor product
#-----------------------------------------------------------------------------
_combined_printing = False
def combined_tensor_printing(combined):
"""Set flag controlling whether tensor products of states should be
printed as a combined bra/ket or as an explicit tensor product of different
bra/kets. This is a global setting for all TensorProduct class instances.
Parameters
----------
combine : bool
When true, tensor product states are combined into one ket/bra, and
when false explicit tensor product notation is used between each
ket/bra.
"""
global _combined_printing
_combined_printing = combined
class TensorProduct(Expr):
"""The tensor product of two or more arguments.
For matrices, this uses ``matrix_tensor_product`` to compute the Kronecker
or tensor product matrix. For other objects a symbolic ``TensorProduct``
instance is returned. The tensor product is a non-commutative
multiplication that is used primarily with operators and states in quantum
mechanics.
Currently, the tensor product distinguishes between commutative and
non-commutative arguments. Commutative arguments are assumed to be scalars
and are pulled out in front of the ``TensorProduct``. Non-commutative
arguments remain in the resulting ``TensorProduct``.
Parameters
==========
args : tuple
A sequence of the objects to take the tensor product of.
Examples
========
Start with a simple tensor product of SymPy matrices::
>>> from sympy import Matrix
>>> from sympy.physics.quantum import TensorProduct
>>> m1 = Matrix([[1,2],[3,4]])
>>> m2 = Matrix([[1,0],[0,1]])
>>> TensorProduct(m1, m2)
Matrix([
[1, 0, 2, 0],
[0, 1, 0, 2],
[3, 0, 4, 0],
[0, 3, 0, 4]])
>>> TensorProduct(m2, m1)
Matrix([
[1, 2, 0, 0],
[3, 4, 0, 0],
[0, 0, 1, 2],
[0, 0, 3, 4]])
We can also construct tensor products of non-commutative symbols:
>>> from sympy import Symbol
>>> A = Symbol('A',commutative=False)
>>> B = Symbol('B',commutative=False)
>>> tp = TensorProduct(A, B)
>>> tp
AxB
We can take the dagger of a tensor product (note the order does NOT reverse
like the dagger of a normal product):
>>> from sympy.physics.quantum import Dagger
>>> Dagger(tp)
Dagger(A)xDagger(B)
Expand can be used to distribute a tensor product across addition:
>>> C = Symbol('C',commutative=False)
>>> tp = TensorProduct(A+B,C)
>>> tp
(A + B)xC
>>> tp.expand(tensorproduct=True)
AxC + BxC
"""
is_commutative = False
def __new__(cls, *args):
if isinstance(args[0], (Matrix, ImmutableMatrix, numpy_ndarray,
scipy_sparse_matrix)):
return matrix_tensor_product(*args)
c_part, new_args = cls.flatten(sympify(args))
c_part = Mul(*c_part)
if len(new_args) == 0:
return c_part
elif len(new_args) == 1:
return c_part * new_args[0]
else:
tp = Expr.__new__(cls, *new_args)
return c_part * tp
@classmethod
def flatten(cls, args):
# TODO: disallow nested TensorProducts.
c_part = []
nc_parts = []
for arg in args:
cp, ncp = arg.args_cnc()
c_part.extend(list(cp))
nc_parts.append(Mul._from_args(ncp))
return c_part, nc_parts
def _eval_adjoint(self):
return TensorProduct(*[Dagger(i) for i in self.args])
def _eval_rewrite(self, rule, args, **hints):
return TensorProduct(*args).expand(tensorproduct=True)
def _sympystr(self, printer, *args):
length = len(self.args)
s = ''
for i in range(length):
if isinstance(self.args[i], (Add, Pow, Mul)):
s = s + '('
s = s + printer._print(self.args[i])
if isinstance(self.args[i], (Add, Pow, Mul)):
s = s + ')'
if i != length - 1:
s = s + 'x'
return s
def _pretty(self, printer, *args):
if (_combined_printing and
(all(isinstance(arg, Ket) for arg in self.args) or
all(isinstance(arg, Bra) for arg in self.args))):
length = len(self.args)
pform = printer._print('', *args)
for i in range(length):
next_pform = printer._print('', *args)
length_i = len(self.args[i].args)
for j in range(length_i):
part_pform = printer._print(self.args[i].args[j], *args)
next_pform = prettyForm(*next_pform.right(part_pform))
if j != length_i - 1:
next_pform = prettyForm(*next_pform.right(', '))
if len(self.args[i].args) > 1:
next_pform = prettyForm(
*next_pform.parens(left='{', right='}'))
pform = prettyForm(*pform.right(next_pform))
if i != length - 1:
pform = prettyForm(*pform.right(',' + ' '))
pform = prettyForm(*pform.left(self.args[0].lbracket))
pform = prettyForm(*pform.right(self.args[0].rbracket))
return pform
length = len(self.args)
pform = printer._print('', *args)
for i in range(length):
next_pform = printer._print(self.args[i], *args)
if isinstance(self.args[i], (Add, Mul)):
next_pform = prettyForm(
*next_pform.parens(left='(', right=')')
)
pform = prettyForm(*pform.right(next_pform))
if i != length - 1:
if printer._use_unicode:
pform = prettyForm(*pform.right('\N{N-ARY CIRCLED TIMES OPERATOR}' + ' '))
else:
pform = prettyForm(*pform.right('x' + ' '))
return pform
def _latex(self, printer, *args):
if (_combined_printing and
(all(isinstance(arg, Ket) for arg in self.args) or
all(isinstance(arg, Bra) for arg in self.args))):
def _label_wrap(label, nlabels):
return label if nlabels == 1 else r"\left\{%s\right\}" % label
s = r", ".join([_label_wrap(arg._print_label_latex(printer, *args),
len(arg.args)) for arg in self.args])
return r"{%s%s%s}" % (self.args[0].lbracket_latex, s,
self.args[0].rbracket_latex)
length = len(self.args)
s = ''
for i in range(length):
if isinstance(self.args[i], (Add, Mul)):
s = s + '\\left('
# The extra {} brackets are needed to get matplotlib's latex
# rendered to render this properly.
s = s + '{' + printer._print(self.args[i], *args) + '}'
if isinstance(self.args[i], (Add, Mul)):
s = s + '\\right)'
if i != length - 1:
s = s + '\\otimes '
return s
def doit(self, **hints):
return TensorProduct(*[item.doit(**hints) for item in self.args])
def _eval_expand_tensorproduct(self, **hints):
"""Distribute TensorProducts across addition."""
args = self.args
add_args = []
for i in range(len(args)):
if isinstance(args[i], Add):
for aa in args[i].args:
tp = TensorProduct(*args[:i] + (aa,) + args[i + 1:])
c_part, nc_part = tp.args_cnc()
# Check for TensorProduct object: is the one object in nc_part, if any:
# (Note: any other object type to be expanded must be added here)
if len(nc_part) == 1 and isinstance(nc_part[0], TensorProduct):
nc_part = (nc_part[0]._eval_expand_tensorproduct(), )
add_args.append(Mul(*c_part)*Mul(*nc_part))
break
if add_args:
return Add(*add_args)
else:
return self
def _eval_trace(self, **kwargs):
indices = kwargs.get('indices', None)
exp = tensor_product_simp(self)
if indices is None or len(indices) == 0:
return Mul(*[Tr(arg).doit() for arg in exp.args])
else:
return Mul(*[Tr(value).doit() if idx in indices else value
for idx, value in enumerate(exp.args)])
def tensor_product_simp_Mul(e):
"""Simplify a Mul with TensorProducts.
Current the main use of this is to simplify a ``Mul`` of ``TensorProduct``s
to a ``TensorProduct`` of ``Muls``. It currently only works for relatively
simple cases where the initial ``Mul`` only has scalars and raw
``TensorProduct``s, not ``Add``, ``Pow``, ``Commutator``s of
``TensorProduct``s.
Parameters
==========
e : Expr
A ``Mul`` of ``TensorProduct``s to be simplified.
Returns
=======
e : Expr
A ``TensorProduct`` of ``Mul``s.
Examples
========
This is an example of the type of simplification that this function
performs::
>>> from sympy.physics.quantum.tensorproduct import \
tensor_product_simp_Mul, TensorProduct
>>> from sympy import Symbol
>>> A = Symbol('A',commutative=False)
>>> B = Symbol('B',commutative=False)
>>> C = Symbol('C',commutative=False)
>>> D = Symbol('D',commutative=False)
>>> e = TensorProduct(A,B)*TensorProduct(C,D)
>>> e
AxB*CxD
>>> tensor_product_simp_Mul(e)
(A*C)x(B*D)
"""
# TODO: This won't work with Muls that have other composites of
# TensorProducts, like an Add, Commutator, etc.
# TODO: This only works for the equivalent of single Qbit gates.
if not isinstance(e, Mul):
return e
c_part, nc_part = e.args_cnc()
n_nc = len(nc_part)
if n_nc == 0:
return e
elif n_nc == 1:
if isinstance(nc_part[0], Pow):
return Mul(*c_part) * tensor_product_simp_Pow(nc_part[0])
return e
elif e.has(TensorProduct):
current = nc_part[0]
if not isinstance(current, TensorProduct):
if isinstance(current, Pow):
if isinstance(current.base, TensorProduct):
current = tensor_product_simp_Pow(current)
else:
raise TypeError('TensorProduct expected, got: %r' % current)
n_terms = len(current.args)
new_args = list(current.args)
for next in nc_part[1:]:
# TODO: check the hilbert spaces of next and current here.
if isinstance(next, TensorProduct):
if n_terms != len(next.args):
raise QuantumError(
'TensorProducts of different lengths: %r and %r' %
(current, next)
)
for i in range(len(new_args)):
new_args[i] = new_args[i] * next.args[i]
else:
if isinstance(next, Pow):
if isinstance(next.base, TensorProduct):
new_tp = tensor_product_simp_Pow(next)
for i in range(len(new_args)):
new_args[i] = new_args[i] * new_tp.args[i]
else:
raise TypeError('TensorProduct expected, got: %r' % next)
else:
raise TypeError('TensorProduct expected, got: %r' % next)
current = next
return Mul(*c_part) * TensorProduct(*new_args)
elif e.has(Pow):
new_args = [ tensor_product_simp_Pow(nc) for nc in nc_part ]
return tensor_product_simp_Mul(Mul(*c_part) * TensorProduct(*new_args))
else:
return e
def tensor_product_simp_Pow(e):
"""Evaluates ``Pow`` expressions whose base is ``TensorProduct``"""
if not isinstance(e, Pow):
return e
if isinstance(e.base, TensorProduct):
return TensorProduct(*[ b**e.exp for b in e.base.args])
else:
return e
def tensor_product_simp(e, **hints):
"""Try to simplify and combine TensorProducts.
In general this will try to pull expressions inside of ``TensorProducts``.
It currently only works for relatively simple cases where the products have
only scalars, raw ``TensorProducts``, not ``Add``, ``Pow``, ``Commutators``
of ``TensorProducts``. It is best to see what it does by showing examples.
Examples
========
>>> from sympy.physics.quantum import tensor_product_simp
>>> from sympy.physics.quantum import TensorProduct
>>> from sympy import Symbol
>>> A = Symbol('A',commutative=False)
>>> B = Symbol('B',commutative=False)
>>> C = Symbol('C',commutative=False)
>>> D = Symbol('D',commutative=False)
First see what happens to products of tensor products:
>>> e = TensorProduct(A,B)*TensorProduct(C,D)
>>> e
AxB*CxD
>>> tensor_product_simp(e)
(A*C)x(B*D)
This is the core logic of this function, and it works inside, powers, sums,
commutators and anticommutators as well:
>>> tensor_product_simp(e**2)
(A*C)x(B*D)**2
"""
if isinstance(e, Add):
return Add(*[tensor_product_simp(arg) for arg in e.args])
elif isinstance(e, Pow):
if isinstance(e.base, TensorProduct):
return tensor_product_simp_Pow(e)
else:
return tensor_product_simp(e.base) ** e.exp
elif isinstance(e, Mul):
return tensor_product_simp_Mul(e)
elif isinstance(e, Commutator):
return Commutator(*[tensor_product_simp(arg) for arg in e.args])
elif isinstance(e, AntiCommutator):
return AntiCommutator(*[tensor_product_simp(arg) for arg in e.args])
else:
return e
PK ]ZZZ�?y� � sympy/physics/quantum/trace.pyfrom sympy.core.add import Add
from sympy.core.containers import Tuple
from sympy.core.expr import Expr
from sympy.core.mul import Mul
from sympy.core.power import Pow
from sympy.core.sorting import default_sort_key
from sympy.core.sympify import sympify
from sympy.matrices import Matrix
def _is_scalar(e):
""" Helper method used in Tr"""
# sympify to set proper attributes
e = sympify(e)
if isinstance(e, Expr):
if (e.is_Integer or e.is_Float or
e.is_Rational or e.is_Number or
(e.is_Symbol and e.is_commutative)
):
return True
return False
def _cycle_permute(l):
""" Cyclic permutations based on canonical ordering
Explanation
===========
This method does the sort based ascii values while
a better approach would be to used lexicographic sort.
TODO: Handle condition such as symbols have subscripts/superscripts
in case of lexicographic sort
"""
if len(l) == 1:
return l
min_item = min(l, key=default_sort_key)
indices = [i for i, x in enumerate(l) if x == min_item]
le = list(l)
le.extend(l) # duplicate and extend string for easy processing
# adding the first min_item index back for easier looping
indices.append(len(l) + indices[0])
# create sublist of items with first item as min_item and last_item
# in each of the sublist is item just before the next occurrence of
# minitem in the cycle formed.
sublist = [[le[indices[i]:indices[i + 1]]] for i in
range(len(indices) - 1)]
# we do comparison of strings by comparing elements
# in each sublist
idx = sublist.index(min(sublist))
ordered_l = le[indices[idx]:indices[idx] + len(l)]
return ordered_l
def _rearrange_args(l):
""" this just moves the last arg to first position
to enable expansion of args
A,B,A ==> A**2,B
"""
if len(l) == 1:
return l
x = list(l[-1:])
x.extend(l[0:-1])
return Mul(*x).args
class Tr(Expr):
""" Generic Trace operation than can trace over:
a) SymPy matrix
b) operators
c) outer products
Parameters
==========
o : operator, matrix, expr
i : tuple/list indices (optional)
Examples
========
# TODO: Need to handle printing
a) Trace(A+B) = Tr(A) + Tr(B)
b) Trace(scalar*Operator) = scalar*Trace(Operator)
>>> from sympy.physics.quantum.trace import Tr
>>> from sympy import symbols, Matrix
>>> a, b = symbols('a b', commutative=True)
>>> A, B = symbols('A B', commutative=False)
>>> Tr(a*A,[2])
a*Tr(A)
>>> m = Matrix([[1,2],[1,1]])
>>> Tr(m)
2
"""
def __new__(cls, *args):
""" Construct a Trace object.
Parameters
==========
args = SymPy expression
indices = tuple/list if indices, optional
"""
# expect no indices,int or a tuple/list/Tuple
if (len(args) == 2):
if not isinstance(args[1], (list, Tuple, tuple)):
indices = Tuple(args[1])
else:
indices = Tuple(*args[1])
expr = args[0]
elif (len(args) == 1):
indices = Tuple()
expr = args[0]
else:
raise ValueError("Arguments to Tr should be of form "
"(expr[, [indices]])")
if isinstance(expr, Matrix):
return expr.trace()
elif hasattr(expr, 'trace') and callable(expr.trace):
#for any objects that have trace() defined e.g numpy
return expr.trace()
elif isinstance(expr, Add):
return Add(*[Tr(arg, indices) for arg in expr.args])
elif isinstance(expr, Mul):
c_part, nc_part = expr.args_cnc()
if len(nc_part) == 0:
return Mul(*c_part)
else:
obj = Expr.__new__(cls, Mul(*nc_part), indices )
#this check is needed to prevent cached instances
#being returned even if len(c_part)==0
return Mul(*c_part)*obj if len(c_part) > 0 else obj
elif isinstance(expr, Pow):
if (_is_scalar(expr.args[0]) and
_is_scalar(expr.args[1])):
return expr
else:
return Expr.__new__(cls, expr, indices)
else:
if (_is_scalar(expr)):
return expr
return Expr.__new__(cls, expr, indices)
@property
def kind(self):
expr = self.args[0]
expr_kind = expr.kind
return expr_kind.element_kind
def doit(self, **hints):
""" Perform the trace operation.
#TODO: Current version ignores the indices set for partial trace.
>>> from sympy.physics.quantum.trace import Tr
>>> from sympy.physics.quantum.operator import OuterProduct
>>> from sympy.physics.quantum.spin import JzKet, JzBra
>>> t = Tr(OuterProduct(JzKet(1,1), JzBra(1,1)))
>>> t.doit()
1
"""
if hasattr(self.args[0], '_eval_trace'):
return self.args[0]._eval_trace(indices=self.args[1])
return self
@property
def is_number(self):
# TODO : improve this implementation
return True
#TODO: Review if the permute method is needed
# and if it needs to return a new instance
def permute(self, pos):
""" Permute the arguments cyclically.
Parameters
==========
pos : integer, if positive, shift-right, else shift-left
Examples
========
>>> from sympy.physics.quantum.trace import Tr
>>> from sympy import symbols
>>> A, B, C, D = symbols('A B C D', commutative=False)
>>> t = Tr(A*B*C*D)
>>> t.permute(2)
Tr(C*D*A*B)
>>> t.permute(-2)
Tr(C*D*A*B)
"""
if pos > 0:
pos = pos % len(self.args[0].args)
else:
pos = -(abs(pos) % len(self.args[0].args))
args = list(self.args[0].args[-pos:] + self.args[0].args[0:-pos])
return Tr(Mul(*(args)))
def _hashable_content(self):
if isinstance(self.args[0], Mul):
args = _cycle_permute(_rearrange_args(self.args[0].args))
else:
args = [self.args[0]]
return tuple(args) + (self.args[1], )
PK ]ZZZ!?�b0 b0 sympy/physics/units/__init__.py# isort:skip_file
"""
Dimensional analysis and unit systems.
This module defines dimension/unit systems and physical quantities. It is
based on a group-theoretical construction where dimensions are represented as
vectors (coefficients being the exponents), and units are defined as a dimension
to which we added a scale.
Quantities are built from a factor and a unit, and are the basic objects that
one will use when doing computations.
All objects except systems and prefixes can be used in SymPy expressions.
Note that as part of a CAS, various objects do not combine automatically
under operations.
Details about the implementation can be found in the documentation, and we
will not repeat all the explanations we gave there concerning our approach.
Ideas about future developments can be found on the `Github wiki
<https://github.com/sympy/sympy/wiki/Unit-systems>`_, and you should consult
this page if you are willing to help.
Useful functions:
- ``find_unit``: easily lookup pre-defined units.
- ``convert_to(expr, newunit)``: converts an expression into the same
expression expressed in another unit.
"""
from .dimensions import Dimension, DimensionSystem
from .unitsystem import UnitSystem
from .util import convert_to
from .quantities import Quantity
from .definitions.dimension_definitions import (
amount_of_substance, acceleration, action, area,
capacitance, charge, conductance, current, energy,
force, frequency, impedance, inductance, length,
luminous_intensity, magnetic_density,
magnetic_flux, mass, momentum, power, pressure, temperature, time,
velocity, voltage, volume
)
Unit = Quantity
speed = velocity
luminosity = luminous_intensity
magnetic_flux_density = magnetic_density
amount = amount_of_substance
from .prefixes import (
# 10-power based:
yotta,
zetta,
exa,
peta,
tera,
giga,
mega,
kilo,
hecto,
deca,
deci,
centi,
milli,
micro,
nano,
pico,
femto,
atto,
zepto,
yocto,
# 2-power based:
kibi,
mebi,
gibi,
tebi,
pebi,
exbi,
)
from .definitions import (
percent, percents,
permille,
rad, radian, radians,
deg, degree, degrees,
sr, steradian, steradians,
mil, angular_mil, angular_mils,
m, meter, meters,
kg, kilogram, kilograms,
s, second, seconds,
A, ampere, amperes,
K, kelvin, kelvins,
mol, mole, moles,
cd, candela, candelas,
g, gram, grams,
mg, milligram, milligrams,
ug, microgram, micrograms,
t, tonne, metric_ton,
newton, newtons, N,
joule, joules, J,
watt, watts, W,
pascal, pascals, Pa, pa,
hertz, hz, Hz,
coulomb, coulombs, C,
volt, volts, v, V,
ohm, ohms,
siemens, S, mho, mhos,
farad, farads, F,
henry, henrys, H,
tesla, teslas, T,
weber, webers, Wb, wb,
optical_power, dioptre, D,
lux, lx,
katal, kat,
gray, Gy,
becquerel, Bq,
km, kilometer, kilometers,
dm, decimeter, decimeters,
cm, centimeter, centimeters,
mm, millimeter, millimeters,
um, micrometer, micrometers, micron, microns,
nm, nanometer, nanometers,
pm, picometer, picometers,
ft, foot, feet,
inch, inches,
yd, yard, yards,
mi, mile, miles,
nmi, nautical_mile, nautical_miles,
angstrom, angstroms,
ha, hectare,
l, L, liter, liters,
dl, dL, deciliter, deciliters,
cl, cL, centiliter, centiliters,
ml, mL, milliliter, milliliters,
ms, millisecond, milliseconds,
us, microsecond, microseconds,
ns, nanosecond, nanoseconds,
ps, picosecond, picoseconds,
minute, minutes,
h, hour, hours,
day, days,
anomalistic_year, anomalistic_years,
sidereal_year, sidereal_years,
tropical_year, tropical_years,
common_year, common_years,
julian_year, julian_years,
draconic_year, draconic_years,
gaussian_year, gaussian_years,
full_moon_cycle, full_moon_cycles,
year, years,
G, gravitational_constant,
c, speed_of_light,
elementary_charge,
hbar,
planck,
eV, electronvolt, electronvolts,
avogadro_number,
avogadro, avogadro_constant,
boltzmann, boltzmann_constant,
stefan, stefan_boltzmann_constant,
R, molar_gas_constant,
faraday_constant,
josephson_constant,
von_klitzing_constant,
Da, dalton, amu, amus, atomic_mass_unit, atomic_mass_constant,
me, electron_rest_mass,
gee, gees, acceleration_due_to_gravity,
u0, magnetic_constant, vacuum_permeability,
e0, electric_constant, vacuum_permittivity,
Z0, vacuum_impedance,
coulomb_constant, electric_force_constant,
atmosphere, atmospheres, atm,
kPa,
bar, bars,
pound, pounds,
psi,
dHg0,
mmHg, torr,
mmu, mmus, milli_mass_unit,
quart, quarts,
ly, lightyear, lightyears,
au, astronomical_unit, astronomical_units,
planck_mass,
planck_time,
planck_temperature,
planck_length,
planck_charge,
planck_area,
planck_volume,
planck_momentum,
planck_energy,
planck_force,
planck_power,
planck_density,
planck_energy_density,
planck_intensity,
planck_angular_frequency,
planck_pressure,
planck_current,
planck_voltage,
planck_impedance,
planck_acceleration,
bit, bits,
byte,
kibibyte, kibibytes,
mebibyte, mebibytes,
gibibyte, gibibytes,
tebibyte, tebibytes,
pebibyte, pebibytes,
exbibyte, exbibytes,
)
from .systems import (
mks, mksa, si
)
def find_unit(quantity, unit_system="SI"):
"""
Return a list of matching units or dimension names.
- If ``quantity`` is a string -- units/dimensions containing the string
`quantity`.
- If ``quantity`` is a unit or dimension -- units having matching base
units or dimensions.
Examples
========
>>> from sympy.physics import units as u
>>> u.find_unit('charge')
['C', 'coulomb', 'coulombs', 'planck_charge', 'elementary_charge']
>>> u.find_unit(u.charge)
['C', 'coulomb', 'coulombs', 'planck_charge', 'elementary_charge']
>>> u.find_unit("ampere")
['ampere', 'amperes']
>>> u.find_unit('angstrom')
['angstrom', 'angstroms']
>>> u.find_unit('volt')
['volt', 'volts', 'electronvolt', 'electronvolts', 'planck_voltage']
>>> u.find_unit(u.inch**3)[:9]
['L', 'l', 'cL', 'cl', 'dL', 'dl', 'mL', 'ml', 'liter']
"""
unit_system = UnitSystem.get_unit_system(unit_system)
import sympy.physics.units as u
rv = []
if isinstance(quantity, str):
rv = [i for i in dir(u) if quantity in i and isinstance(getattr(u, i), Quantity)]
dim = getattr(u, quantity)
if isinstance(dim, Dimension):
rv.extend(find_unit(dim))
else:
for i in sorted(dir(u)):
other = getattr(u, i)
if not isinstance(other, Quantity):
continue
if isinstance(quantity, Quantity):
if quantity.dimension == other.dimension:
rv.append(str(i))
elif isinstance(quantity, Dimension):
if other.dimension == quantity:
rv.append(str(i))
elif other.dimension == Dimension(unit_system.get_dimensional_expr(quantity)):
rv.append(str(i))
return sorted(set(rv), key=lambda x: (len(x), x))
# NOTE: the old units module had additional variables:
# 'density', 'illuminance', 'resistance'.
# They were not dimensions, but units (old Unit class).
__all__ = [
'Dimension', 'DimensionSystem',
'UnitSystem',
'convert_to',
'Quantity',
'amount_of_substance', 'acceleration', 'action', 'area',
'capacitance', 'charge', 'conductance', 'current', 'energy',
'force', 'frequency', 'impedance', 'inductance', 'length',
'luminous_intensity', 'magnetic_density',
'magnetic_flux', 'mass', 'momentum', 'power', 'pressure', 'temperature', 'time',
'velocity', 'voltage', 'volume',
'Unit',
'speed',
'luminosity',
'magnetic_flux_density',
'amount',
'yotta',
'zetta',
'exa',
'peta',
'tera',
'giga',
'mega',
'kilo',
'hecto',
'deca',
'deci',
'centi',
'milli',
'micro',
'nano',
'pico',
'femto',
'atto',
'zepto',
'yocto',
'kibi',
'mebi',
'gibi',
'tebi',
'pebi',
'exbi',
'percent', 'percents',
'permille',
'rad', 'radian', 'radians',
'deg', 'degree', 'degrees',
'sr', 'steradian', 'steradians',
'mil', 'angular_mil', 'angular_mils',
'm', 'meter', 'meters',
'kg', 'kilogram', 'kilograms',
's', 'second', 'seconds',
'A', 'ampere', 'amperes',
'K', 'kelvin', 'kelvins',
'mol', 'mole', 'moles',
'cd', 'candela', 'candelas',
'g', 'gram', 'grams',
'mg', 'milligram', 'milligrams',
'ug', 'microgram', 'micrograms',
't', 'tonne', 'metric_ton',
'newton', 'newtons', 'N',
'joule', 'joules', 'J',
'watt', 'watts', 'W',
'pascal', 'pascals', 'Pa', 'pa',
'hertz', 'hz', 'Hz',
'coulomb', 'coulombs', 'C',
'volt', 'volts', 'v', 'V',
'ohm', 'ohms',
'siemens', 'S', 'mho', 'mhos',
'farad', 'farads', 'F',
'henry', 'henrys', 'H',
'tesla', 'teslas', 'T',
'weber', 'webers', 'Wb', 'wb',
'optical_power', 'dioptre', 'D',
'lux', 'lx',
'katal', 'kat',
'gray', 'Gy',
'becquerel', 'Bq',
'km', 'kilometer', 'kilometers',
'dm', 'decimeter', 'decimeters',
'cm', 'centimeter', 'centimeters',
'mm', 'millimeter', 'millimeters',
'um', 'micrometer', 'micrometers', 'micron', 'microns',
'nm', 'nanometer', 'nanometers',
'pm', 'picometer', 'picometers',
'ft', 'foot', 'feet',
'inch', 'inches',
'yd', 'yard', 'yards',
'mi', 'mile', 'miles',
'nmi', 'nautical_mile', 'nautical_miles',
'angstrom', 'angstroms',
'ha', 'hectare',
'l', 'L', 'liter', 'liters',
'dl', 'dL', 'deciliter', 'deciliters',
'cl', 'cL', 'centiliter', 'centiliters',
'ml', 'mL', 'milliliter', 'milliliters',
'ms', 'millisecond', 'milliseconds',
'us', 'microsecond', 'microseconds',
'ns', 'nanosecond', 'nanoseconds',
'ps', 'picosecond', 'picoseconds',
'minute', 'minutes',
'h', 'hour', 'hours',
'day', 'days',
'anomalistic_year', 'anomalistic_years',
'sidereal_year', 'sidereal_years',
'tropical_year', 'tropical_years',
'common_year', 'common_years',
'julian_year', 'julian_years',
'draconic_year', 'draconic_years',
'gaussian_year', 'gaussian_years',
'full_moon_cycle', 'full_moon_cycles',
'year', 'years',
'G', 'gravitational_constant',
'c', 'speed_of_light',
'elementary_charge',
'hbar',
'planck',
'eV', 'electronvolt', 'electronvolts',
'avogadro_number',
'avogadro', 'avogadro_constant',
'boltzmann', 'boltzmann_constant',
'stefan', 'stefan_boltzmann_constant',
'R', 'molar_gas_constant',
'faraday_constant',
'josephson_constant',
'von_klitzing_constant',
'Da', 'dalton', 'amu', 'amus', 'atomic_mass_unit', 'atomic_mass_constant',
'me', 'electron_rest_mass',
'gee', 'gees', 'acceleration_due_to_gravity',
'u0', 'magnetic_constant', 'vacuum_permeability',
'e0', 'electric_constant', 'vacuum_permittivity',
'Z0', 'vacuum_impedance',
'coulomb_constant', 'electric_force_constant',
'atmosphere', 'atmospheres', 'atm',
'kPa',
'bar', 'bars',
'pound', 'pounds',
'psi',
'dHg0',
'mmHg', 'torr',
'mmu', 'mmus', 'milli_mass_unit',
'quart', 'quarts',
'ly', 'lightyear', 'lightyears',
'au', 'astronomical_unit', 'astronomical_units',
'planck_mass',
'planck_time',
'planck_temperature',
'planck_length',
'planck_charge',
'planck_area',
'planck_volume',
'planck_momentum',
'planck_energy',
'planck_force',
'planck_power',
'planck_density',
'planck_energy_density',
'planck_intensity',
'planck_angular_frequency',
'planck_pressure',
'planck_current',
'planck_voltage',
'planck_impedance',
'planck_acceleration',
'bit', 'bits',
'byte',
'kibibyte', 'kibibytes',
'mebibyte', 'mebibytes',
'gibibyte', 'gibibytes',
'tebibyte', 'tebibytes',
'pebibyte', 'pebibytes',
'exbibyte', 'exbibytes',
'mks', 'mksa', 'si',
]
PK ]ZZZd<�Q �Q ! sympy/physics/units/dimensions.py"""
Definition of physical dimensions.
Unit systems will be constructed on top of these dimensions.
Most of the examples in the doc use MKS system and are presented from the
computer point of view: from a human point, adding length to time is not legal
in MKS but it is in natural system; for a computer in natural system there is
no time dimension (but a velocity dimension instead) - in the basis - so the
question of adding time to length has no meaning.
"""
from __future__ import annotations
import collections
from functools import reduce
from sympy.core.basic import Basic
from sympy.core.containers import (Dict, Tuple)
from sympy.core.singleton import S
from sympy.core.sorting import default_sort_key
from sympy.core.symbol import Symbol
from sympy.core.sympify import sympify
from sympy.matrices.dense import Matrix
from sympy.functions.elementary.trigonometric import TrigonometricFunction
from sympy.core.expr import Expr
from sympy.core.power import Pow
class _QuantityMapper:
_quantity_scale_factors_global: dict[Expr, Expr] = {}
_quantity_dimensional_equivalence_map_global: dict[Expr, Expr] = {}
_quantity_dimension_global: dict[Expr, Expr] = {}
def __init__(self, *args, **kwargs):
self._quantity_dimension_map = {}
self._quantity_scale_factors = {}
def set_quantity_dimension(self, quantity, dimension):
"""
Set the dimension for the quantity in a unit system.
If this relation is valid in every unit system, use
``quantity.set_global_dimension(dimension)`` instead.
"""
from sympy.physics.units import Quantity
dimension = sympify(dimension)
if not isinstance(dimension, Dimension):
if dimension == 1:
dimension = Dimension(1)
else:
raise ValueError("expected dimension or 1")
elif isinstance(dimension, Quantity):
dimension = self.get_quantity_dimension(dimension)
self._quantity_dimension_map[quantity] = dimension
def set_quantity_scale_factor(self, quantity, scale_factor):
"""
Set the scale factor of a quantity relative to another quantity.
It should be used only once per quantity to just one other quantity,
the algorithm will then be able to compute the scale factors to all
other quantities.
In case the scale factor is valid in every unit system, please use
``quantity.set_global_relative_scale_factor(scale_factor)`` instead.
"""
from sympy.physics.units import Quantity
from sympy.physics.units.prefixes import Prefix
scale_factor = sympify(scale_factor)
# replace all prefixes by their ratio to canonical units:
scale_factor = scale_factor.replace(
lambda x: isinstance(x, Prefix),
lambda x: x.scale_factor
)
# replace all quantities by their ratio to canonical units:
scale_factor = scale_factor.replace(
lambda x: isinstance(x, Quantity),
lambda x: self.get_quantity_scale_factor(x)
)
self._quantity_scale_factors[quantity] = scale_factor
def get_quantity_dimension(self, unit):
from sympy.physics.units import Quantity
# First look-up the local dimension map, then the global one:
if unit in self._quantity_dimension_map:
return self._quantity_dimension_map[unit]
if unit in self._quantity_dimension_global:
return self._quantity_dimension_global[unit]
if unit in self._quantity_dimensional_equivalence_map_global:
dep_unit = self._quantity_dimensional_equivalence_map_global[unit]
if isinstance(dep_unit, Quantity):
return self.get_quantity_dimension(dep_unit)
else:
return Dimension(self.get_dimensional_expr(dep_unit))
if isinstance(unit, Quantity):
return Dimension(unit.name)
else:
return Dimension(1)
def get_quantity_scale_factor(self, unit):
if unit in self._quantity_scale_factors:
return self._quantity_scale_factors[unit]
if unit in self._quantity_scale_factors_global:
mul_factor, other_unit = self._quantity_scale_factors_global[unit]
return mul_factor*self.get_quantity_scale_factor(other_unit)
return S.One
class Dimension(Expr):
"""
This class represent the dimension of a physical quantities.
The ``Dimension`` constructor takes as parameters a name and an optional
symbol.
For example, in classical mechanics we know that time is different from
temperature and dimensions make this difference (but they do not provide
any measure of these quantites.
>>> from sympy.physics.units import Dimension
>>> length = Dimension('length')
>>> length
Dimension(length)
>>> time = Dimension('time')
>>> time
Dimension(time)
Dimensions can be composed using multiplication, division and
exponentiation (by a number) to give new dimensions. Addition and
subtraction is defined only when the two objects are the same dimension.
>>> velocity = length / time
>>> velocity
Dimension(length/time)
It is possible to use a dimension system object to get the dimensionsal
dependencies of a dimension, for example the dimension system used by the
SI units convention can be used:
>>> from sympy.physics.units.systems.si import dimsys_SI
>>> dimsys_SI.get_dimensional_dependencies(velocity)
{Dimension(length, L): 1, Dimension(time, T): -1}
>>> length + length
Dimension(length)
>>> l2 = length**2
>>> l2
Dimension(length**2)
>>> dimsys_SI.get_dimensional_dependencies(l2)
{Dimension(length, L): 2}
"""
_op_priority = 13.0
# XXX: This doesn't seem to be used anywhere...
_dimensional_dependencies = {} # type: ignore
is_commutative = True
is_number = False
# make sqrt(M**2) --> M
is_positive = True
is_real = True
def __new__(cls, name, symbol=None):
if isinstance(name, str):
name = Symbol(name)
else:
name = sympify(name)
if not isinstance(name, Expr):
raise TypeError("Dimension name needs to be a valid math expression")
if isinstance(symbol, str):
symbol = Symbol(symbol)
elif symbol is not None:
assert isinstance(symbol, Symbol)
obj = Expr.__new__(cls, name)
obj._name = name
obj._symbol = symbol
return obj
@property
def name(self):
return self._name
@property
def symbol(self):
return self._symbol
def __str__(self):
"""
Display the string representation of the dimension.
"""
if self.symbol is None:
return "Dimension(%s)" % (self.name)
else:
return "Dimension(%s, %s)" % (self.name, self.symbol)
def __repr__(self):
return self.__str__()
def __neg__(self):
return self
def __add__(self, other):
from sympy.physics.units.quantities import Quantity
other = sympify(other)
if isinstance(other, Basic):
if other.has(Quantity):
raise TypeError("cannot sum dimension and quantity")
if isinstance(other, Dimension) and self == other:
return self
return super().__add__(other)
return self
def __radd__(self, other):
return self.__add__(other)
def __sub__(self, other):
# there is no notion of ordering (or magnitude) among dimension,
# subtraction is equivalent to addition when the operation is legal
return self + other
def __rsub__(self, other):
# there is no notion of ordering (or magnitude) among dimension,
# subtraction is equivalent to addition when the operation is legal
return self + other
def __pow__(self, other):
return self._eval_power(other)
def _eval_power(self, other):
other = sympify(other)
return Dimension(self.name**other)
def __mul__(self, other):
from sympy.physics.units.quantities import Quantity
if isinstance(other, Basic):
if other.has(Quantity):
raise TypeError("cannot sum dimension and quantity")
if isinstance(other, Dimension):
return Dimension(self.name*other.name)
if not other.free_symbols: # other.is_number cannot be used
return self
return super().__mul__(other)
return self
def __rmul__(self, other):
return self.__mul__(other)
def __truediv__(self, other):
return self*Pow(other, -1)
def __rtruediv__(self, other):
return other * pow(self, -1)
@classmethod
def _from_dimensional_dependencies(cls, dependencies):
return reduce(lambda x, y: x * y, (
d**e for d, e in dependencies.items()
), 1)
def has_integer_powers(self, dim_sys):
"""
Check if the dimension object has only integer powers.
All the dimension powers should be integers, but rational powers may
appear in intermediate steps. This method may be used to check that the
final result is well-defined.
"""
return all(dpow.is_Integer for dpow in dim_sys.get_dimensional_dependencies(self).values())
# Create dimensions according to the base units in MKSA.
# For other unit systems, they can be derived by transforming the base
# dimensional dependency dictionary.
class DimensionSystem(Basic, _QuantityMapper):
r"""
DimensionSystem represents a coherent set of dimensions.
The constructor takes three parameters:
- base dimensions;
- derived dimensions: these are defined in terms of the base dimensions
(for example velocity is defined from the division of length by time);
- dependency of dimensions: how the derived dimensions depend
on the base dimensions.
Optionally either the ``derived_dims`` or the ``dimensional_dependencies``
may be omitted.
"""
def __new__(cls, base_dims, derived_dims=(), dimensional_dependencies={}):
dimensional_dependencies = dict(dimensional_dependencies)
def parse_dim(dim):
if isinstance(dim, str):
dim = Dimension(Symbol(dim))
elif isinstance(dim, Dimension):
pass
elif isinstance(dim, Symbol):
dim = Dimension(dim)
else:
raise TypeError("%s wrong type" % dim)
return dim
base_dims = [parse_dim(i) for i in base_dims]
derived_dims = [parse_dim(i) for i in derived_dims]
for dim in base_dims:
if (dim in dimensional_dependencies
and (len(dimensional_dependencies[dim]) != 1 or
dimensional_dependencies[dim].get(dim, None) != 1)):
raise IndexError("Repeated value in base dimensions")
dimensional_dependencies[dim] = Dict({dim: 1})
def parse_dim_name(dim):
if isinstance(dim, Dimension):
return dim
elif isinstance(dim, str):
return Dimension(Symbol(dim))
elif isinstance(dim, Symbol):
return Dimension(dim)
else:
raise TypeError("unrecognized type %s for %s" % (type(dim), dim))
for dim in dimensional_dependencies.keys():
dim = parse_dim(dim)
if (dim not in derived_dims) and (dim not in base_dims):
derived_dims.append(dim)
def parse_dict(d):
return Dict({parse_dim_name(i): j for i, j in d.items()})
# Make sure everything is a SymPy type:
dimensional_dependencies = {parse_dim_name(i): parse_dict(j) for i, j in
dimensional_dependencies.items()}
for dim in derived_dims:
if dim in base_dims:
raise ValueError("Dimension %s both in base and derived" % dim)
if dim not in dimensional_dependencies:
# TODO: should this raise a warning?
dimensional_dependencies[dim] = Dict({dim: 1})
base_dims.sort(key=default_sort_key)
derived_dims.sort(key=default_sort_key)
base_dims = Tuple(*base_dims)
derived_dims = Tuple(*derived_dims)
dimensional_dependencies = Dict({i: Dict(j) for i, j in dimensional_dependencies.items()})
obj = Basic.__new__(cls, base_dims, derived_dims, dimensional_dependencies)
return obj
@property
def base_dims(self):
return self.args[0]
@property
def derived_dims(self):
return self.args[1]
@property
def dimensional_dependencies(self):
return self.args[2]
def _get_dimensional_dependencies_for_name(self, dimension):
if isinstance(dimension, str):
dimension = Dimension(Symbol(dimension))
elif not isinstance(dimension, Dimension):
dimension = Dimension(dimension)
if dimension.name.is_Symbol:
# Dimensions not included in the dependencies are considered
# as base dimensions:
return dict(self.dimensional_dependencies.get(dimension, {dimension: 1}))
if dimension.name.is_number or dimension.name.is_NumberSymbol:
return {}
get_for_name = self._get_dimensional_dependencies_for_name
if dimension.name.is_Mul:
ret = collections.defaultdict(int)
dicts = [get_for_name(i) for i in dimension.name.args]
for d in dicts:
for k, v in d.items():
ret[k] += v
return {k: v for (k, v) in ret.items() if v != 0}
if dimension.name.is_Add:
dicts = [get_for_name(i) for i in dimension.name.args]
if all(d == dicts[0] for d in dicts[1:]):
return dicts[0]
raise TypeError("Only equivalent dimensions can be added or subtracted.")
if dimension.name.is_Pow:
dim_base = get_for_name(dimension.name.base)
dim_exp = get_for_name(dimension.name.exp)
if dim_exp == {} or dimension.name.exp.is_Symbol:
return {k: v * dimension.name.exp for (k, v) in dim_base.items()}
else:
raise TypeError("The exponent for the power operator must be a Symbol or dimensionless.")
if dimension.name.is_Function:
args = (Dimension._from_dimensional_dependencies(
get_for_name(arg)) for arg in dimension.name.args)
result = dimension.name.func(*args)
dicts = [get_for_name(i) for i in dimension.name.args]
if isinstance(result, Dimension):
return self.get_dimensional_dependencies(result)
elif result.func == dimension.name.func:
if isinstance(dimension.name, TrigonometricFunction):
if dicts[0] in ({}, {Dimension('angle'): 1}):
return {}
else:
raise TypeError("The input argument for the function {} must be dimensionless or have dimensions of angle.".format(dimension.func))
else:
if all(item == {} for item in dicts):
return {}
else:
raise TypeError("The input arguments for the function {} must be dimensionless.".format(dimension.func))
else:
return get_for_name(result)
raise TypeError("Type {} not implemented for get_dimensional_dependencies".format(type(dimension.name)))
def get_dimensional_dependencies(self, name, mark_dimensionless=False):
dimdep = self._get_dimensional_dependencies_for_name(name)
if mark_dimensionless and dimdep == {}:
return {Dimension(1): 1}
return dict(dimdep.items())
def equivalent_dims(self, dim1, dim2):
deps1 = self.get_dimensional_dependencies(dim1)
deps2 = self.get_dimensional_dependencies(dim2)
return deps1 == deps2
def extend(self, new_base_dims, new_derived_dims=(), new_dim_deps=None):
deps = dict(self.dimensional_dependencies)
if new_dim_deps:
deps.update(new_dim_deps)
new_dim_sys = DimensionSystem(
tuple(self.base_dims) + tuple(new_base_dims),
tuple(self.derived_dims) + tuple(new_derived_dims),
deps
)
new_dim_sys._quantity_dimension_map.update(self._quantity_dimension_map)
new_dim_sys._quantity_scale_factors.update(self._quantity_scale_factors)
return new_dim_sys
def is_dimensionless(self, dimension):
"""
Check if the dimension object really has a dimension.
A dimension should have at least one component with non-zero power.
"""
if dimension.name == 1:
return True
return self.get_dimensional_dependencies(dimension) == {}
@property
def list_can_dims(self):
"""
Useless method, kept for compatibility with previous versions.
DO NOT USE.
List all canonical dimension names.
"""
dimset = set()
for i in self.base_dims:
dimset.update(set(self.get_dimensional_dependencies(i).keys()))
return tuple(sorted(dimset, key=str))
@property
def inv_can_transf_matrix(self):
"""
Useless method, kept for compatibility with previous versions.
DO NOT USE.
Compute the inverse transformation matrix from the base to the
canonical dimension basis.
It corresponds to the matrix where columns are the vector of base
dimensions in canonical basis.
This matrix will almost never be used because dimensions are always
defined with respect to the canonical basis, so no work has to be done
to get them in this basis. Nonetheless if this matrix is not square
(or not invertible) it means that we have chosen a bad basis.
"""
matrix = reduce(lambda x, y: x.row_join(y),
[self.dim_can_vector(d) for d in self.base_dims])
return matrix
@property
def can_transf_matrix(self):
"""
Useless method, kept for compatibility with previous versions.
DO NOT USE.
Return the canonical transformation matrix from the canonical to the
base dimension basis.
It is the inverse of the matrix computed with inv_can_transf_matrix().
"""
#TODO: the inversion will fail if the system is inconsistent, for
# example if the matrix is not a square
return reduce(lambda x, y: x.row_join(y),
[self.dim_can_vector(d) for d in sorted(self.base_dims, key=str)]
).inv()
def dim_can_vector(self, dim):
"""
Useless method, kept for compatibility with previous versions.
DO NOT USE.
Dimensional representation in terms of the canonical base dimensions.
"""
vec = []
for d in self.list_can_dims:
vec.append(self.get_dimensional_dependencies(dim).get(d, 0))
return Matrix(vec)
def dim_vector(self, dim):
"""
Useless method, kept for compatibility with previous versions.
DO NOT USE.
Vector representation in terms of the base dimensions.
"""
return self.can_transf_matrix * Matrix(self.dim_can_vector(dim))
def print_dim_base(self, dim):
"""
Give the string expression of a dimension in term of the basis symbols.
"""
dims = self.dim_vector(dim)
symbols = [i.symbol if i.symbol is not None else i.name for i in self.base_dims]
res = S.One
for (s, p) in zip(symbols, dims):
res *= s**p
return res
@property
def dim(self):
"""
Useless method, kept for compatibility with previous versions.
DO NOT USE.
Give the dimension of the system.
That is return the number of dimensions forming the basis.
"""
return len(self.base_dims)
@property
def is_consistent(self):
"""
Useless method, kept for compatibility with previous versions.
DO NOT USE.
Check if the system is well defined.
"""
# not enough or too many base dimensions compared to independent
# dimensions
# in vector language: the set of vectors do not form a basis
return self.inv_can_transf_matrix.is_square
PK ]ZZZ '�|t t sympy/physics/units/prefixes.py"""
Module defining unit prefixe class and some constants.
Constant dict for SI and binary prefixes are defined as PREFIXES and
BIN_PREFIXES.
"""
from sympy.core.expr import Expr
from sympy.core.sympify import sympify
from sympy.core.singleton import S
class Prefix(Expr):
"""
This class represent prefixes, with their name, symbol and factor.
Prefixes are used to create derived units from a given unit. They should
always be encapsulated into units.
The factor is constructed from a base (default is 10) to some power, and
it gives the total multiple or fraction. For example the kilometer km
is constructed from the meter (factor 1) and the kilo (10 to the power 3,
i.e. 1000). The base can be changed to allow e.g. binary prefixes.
A prefix multiplied by something will always return the product of this
other object times the factor, except if the other object:
- is a prefix and they can be combined into a new prefix;
- defines multiplication with prefixes (which is the case for the Unit
class).
"""
_op_priority = 13.0
is_commutative = True
def __new__(cls, name, abbrev, exponent, base=sympify(10), latex_repr=None):
name = sympify(name)
abbrev = sympify(abbrev)
exponent = sympify(exponent)
base = sympify(base)
obj = Expr.__new__(cls, name, abbrev, exponent, base)
obj._name = name
obj._abbrev = abbrev
obj._scale_factor = base**exponent
obj._exponent = exponent
obj._base = base
obj._latex_repr = latex_repr
return obj
@property
def name(self):
return self._name
@property
def abbrev(self):
return self._abbrev
@property
def scale_factor(self):
return self._scale_factor
def _latex(self, printer):
if self._latex_repr is None:
return r'\text{%s}' % self._abbrev
return self._latex_repr
@property
def base(self):
return self._base
def __str__(self):
return str(self._abbrev)
def __repr__(self):
if self.base == 10:
return "Prefix(%r, %r, %r)" % (
str(self.name), str(self.abbrev), self._exponent)
else:
return "Prefix(%r, %r, %r, %r)" % (
str(self.name), str(self.abbrev), self._exponent, self.base)
def __mul__(self, other):
from sympy.physics.units import Quantity
if not isinstance(other, (Quantity, Prefix)):
return super().__mul__(other)
fact = self.scale_factor * other.scale_factor
if isinstance(other, Prefix):
if fact == 1:
return S.One
# simplify prefix
for p in PREFIXES:
if PREFIXES[p].scale_factor == fact:
return PREFIXES[p]
return fact
return self.scale_factor * other
def __truediv__(self, other):
if not hasattr(other, "scale_factor"):
return super().__truediv__(other)
fact = self.scale_factor / other.scale_factor
if fact == 1:
return S.One
elif isinstance(other, Prefix):
for p in PREFIXES:
if PREFIXES[p].scale_factor == fact:
return PREFIXES[p]
return fact
return self.scale_factor / other
def __rtruediv__(self, other):
if other == 1:
for p in PREFIXES:
if PREFIXES[p].scale_factor == 1 / self.scale_factor:
return PREFIXES[p]
return other / self.scale_factor
def prefix_unit(unit, prefixes):
"""
Return a list of all units formed by unit and the given prefixes.
You can use the predefined PREFIXES or BIN_PREFIXES, but you can also
pass as argument a subdict of them if you do not want all prefixed units.
>>> from sympy.physics.units.prefixes import (PREFIXES,
... prefix_unit)
>>> from sympy.physics.units import m
>>> pref = {"m": PREFIXES["m"], "c": PREFIXES["c"], "d": PREFIXES["d"]}
>>> prefix_unit(m, pref) # doctest: +SKIP
[millimeter, centimeter, decimeter]
"""
from sympy.physics.units.quantities import Quantity
from sympy.physics.units import UnitSystem
prefixed_units = []
for prefix in prefixes.values():
quantity = Quantity(
"%s%s" % (prefix.name, unit.name),
abbrev=("%s%s" % (prefix.abbrev, unit.abbrev)),
is_prefixed=True,
)
UnitSystem._quantity_dimensional_equivalence_map_global[quantity] = unit
UnitSystem._quantity_scale_factors_global[quantity] = (prefix.scale_factor, unit)
prefixed_units.append(quantity)
return prefixed_units
yotta = Prefix('yotta', 'Y', 24)
zetta = Prefix('zetta', 'Z', 21)
exa = Prefix('exa', 'E', 18)
peta = Prefix('peta', 'P', 15)
tera = Prefix('tera', 'T', 12)
giga = Prefix('giga', 'G', 9)
mega = Prefix('mega', 'M', 6)
kilo = Prefix('kilo', 'k', 3)
hecto = Prefix('hecto', 'h', 2)
deca = Prefix('deca', 'da', 1)
deci = Prefix('deci', 'd', -1)
centi = Prefix('centi', 'c', -2)
milli = Prefix('milli', 'm', -3)
micro = Prefix('micro', 'mu', -6, latex_repr=r"\mu")
nano = Prefix('nano', 'n', -9)
pico = Prefix('pico', 'p', -12)
femto = Prefix('femto', 'f', -15)
atto = Prefix('atto', 'a', -18)
zepto = Prefix('zepto', 'z', -21)
yocto = Prefix('yocto', 'y', -24)
# https://physics.nist.gov/cuu/Units/prefixes.html
PREFIXES = {
'Y': yotta,
'Z': zetta,
'E': exa,
'P': peta,
'T': tera,
'G': giga,
'M': mega,
'k': kilo,
'h': hecto,
'da': deca,
'd': deci,
'c': centi,
'm': milli,
'mu': micro,
'n': nano,
'p': pico,
'f': femto,
'a': atto,
'z': zepto,
'y': yocto,
}
kibi = Prefix('kibi', 'Y', 10, 2)
mebi = Prefix('mebi', 'Y', 20, 2)
gibi = Prefix('gibi', 'Y', 30, 2)
tebi = Prefix('tebi', 'Y', 40, 2)
pebi = Prefix('pebi', 'Y', 50, 2)
exbi = Prefix('exbi', 'Y', 60, 2)
# https://physics.nist.gov/cuu/Units/binary.html
BIN_PREFIXES = {
'Ki': kibi,
'Mi': mebi,
'Gi': gibi,
'Ti': tebi,
'Pi': pebi,
'Ei': exbi,
}
PK ]ZZZH4h�? ? ! sympy/physics/units/quantities.py"""
Physical quantities.
"""
from sympy.core.expr import AtomicExpr
from sympy.core.symbol import Symbol
from sympy.core.sympify import sympify
from sympy.physics.units.dimensions import _QuantityMapper
from sympy.physics.units.prefixes import Prefix
class Quantity(AtomicExpr):
"""
Physical quantity: can be a unit of measure, a constant or a generic quantity.
"""
is_commutative = True
is_real = True
is_number = False
is_nonzero = True
is_physical_constant = False
_diff_wrt = True
def __new__(cls, name, abbrev=None,
latex_repr=None, pretty_unicode_repr=None,
pretty_ascii_repr=None, mathml_presentation_repr=None,
is_prefixed=False,
**assumptions):
if not isinstance(name, Symbol):
name = Symbol(name)
if abbrev is None:
abbrev = name
elif isinstance(abbrev, str):
abbrev = Symbol(abbrev)
# HACK: These are here purely for type checking. They actually get assigned below.
cls._is_prefixed = is_prefixed
obj = AtomicExpr.__new__(cls, name, abbrev)
obj._name = name
obj._abbrev = abbrev
obj._latex_repr = latex_repr
obj._unicode_repr = pretty_unicode_repr
obj._ascii_repr = pretty_ascii_repr
obj._mathml_repr = mathml_presentation_repr
obj._is_prefixed = is_prefixed
return obj
def set_global_dimension(self, dimension):
_QuantityMapper._quantity_dimension_global[self] = dimension
def set_global_relative_scale_factor(self, scale_factor, reference_quantity):
"""
Setting a scale factor that is valid across all unit system.
"""
from sympy.physics.units import UnitSystem
scale_factor = sympify(scale_factor)
if isinstance(scale_factor, Prefix):
self._is_prefixed = True
# replace all prefixes by their ratio to canonical units:
scale_factor = scale_factor.replace(
lambda x: isinstance(x, Prefix),
lambda x: x.scale_factor
)
scale_factor = sympify(scale_factor)
UnitSystem._quantity_scale_factors_global[self] = (scale_factor, reference_quantity)
UnitSystem._quantity_dimensional_equivalence_map_global[self] = reference_quantity
@property
def name(self):
return self._name
@property
def dimension(self):
from sympy.physics.units import UnitSystem
unit_system = UnitSystem.get_default_unit_system()
return unit_system.get_quantity_dimension(self)
@property
def abbrev(self):
"""
Symbol representing the unit name.
Prepend the abbreviation with the prefix symbol if it is defines.
"""
return self._abbrev
@property
def scale_factor(self):
"""
Overall magnitude of the quantity as compared to the canonical units.
"""
from sympy.physics.units import UnitSystem
unit_system = UnitSystem.get_default_unit_system()
return unit_system.get_quantity_scale_factor(self)
def _eval_is_positive(self):
return True
def _eval_is_constant(self):
return True
def _eval_Abs(self):
return self
def _eval_subs(self, old, new):
if isinstance(new, Quantity) and self != old:
return self
def _latex(self, printer):
if self._latex_repr:
return self._latex_repr
else:
return r'\text{{{}}}'.format(self.args[1] \
if len(self.args) >= 2 else self.args[0])
def convert_to(self, other, unit_system="SI"):
"""
Convert the quantity to another quantity of same dimensions.
Examples
========
>>> from sympy.physics.units import speed_of_light, meter, second
>>> speed_of_light
speed_of_light
>>> speed_of_light.convert_to(meter/second)
299792458*meter/second
>>> from sympy.physics.units import liter
>>> liter.convert_to(meter**3)
meter**3/1000
"""
from .util import convert_to
return convert_to(self, other, unit_system)
@property
def free_symbols(self):
"""Return free symbols from quantity."""
return set()
@property
def is_prefixed(self):
"""Whether or not the quantity is prefixed. Eg. `kilogram` is prefixed, but `gram` is not."""
return self._is_prefixed
class PhysicalConstant(Quantity):
"""Represents a physical constant, eg. `speed_of_light` or `avogadro_constant`."""
is_physical_constant = True
PK ]ZZZf��i� � ! sympy/physics/units/unitsystem.py"""
Unit system for physical quantities; include definition of constants.
"""
from typing import Dict as tDict, Set as tSet
from sympy.core.add import Add
from sympy.core.function import (Derivative, Function)
from sympy.core.mul import Mul
from sympy.core.power import Pow
from sympy.core.singleton import S
from sympy.physics.units.dimensions import _QuantityMapper
from sympy.physics.units.quantities import Quantity
from .dimensions import Dimension
class UnitSystem(_QuantityMapper):
"""
UnitSystem represents a coherent set of units.
A unit system is basically a dimension system with notions of scales. Many
of the methods are defined in the same way.
It is much better if all base units have a symbol.
"""
_unit_systems = {} # type: tDict[str, UnitSystem]
def __init__(self, base_units, units=(), name="", descr="", dimension_system=None, derived_units: tDict[Dimension, Quantity]={}):
UnitSystem._unit_systems[name] = self
self.name = name
self.descr = descr
self._base_units = base_units
self._dimension_system = dimension_system
self._units = tuple(set(base_units) | set(units))
self._base_units = tuple(base_units)
self._derived_units = derived_units
super().__init__()
def __str__(self):
"""
Return the name of the system.
If it does not exist, then it makes a list of symbols (or names) of
the base dimensions.
"""
if self.name != "":
return self.name
else:
return "UnitSystem((%s))" % ", ".join(
str(d) for d in self._base_units)
def __repr__(self):
return '<UnitSystem: %s>' % repr(self._base_units)
def extend(self, base, units=(), name="", description="", dimension_system=None, derived_units: tDict[Dimension, Quantity]={}):
"""Extend the current system into a new one.
Take the base and normal units of the current system to merge
them to the base and normal units given in argument.
If not provided, name and description are overridden by empty strings.
"""
base = self._base_units + tuple(base)
units = self._units + tuple(units)
return UnitSystem(base, units, name, description, dimension_system, {**self._derived_units, **derived_units})
def get_dimension_system(self):
return self._dimension_system
def get_quantity_dimension(self, unit):
qdm = self.get_dimension_system()._quantity_dimension_map
if unit in qdm:
return qdm[unit]
return super().get_quantity_dimension(unit)
def get_quantity_scale_factor(self, unit):
qsfm = self.get_dimension_system()._quantity_scale_factors
if unit in qsfm:
return qsfm[unit]
return super().get_quantity_scale_factor(unit)
@staticmethod
def get_unit_system(unit_system):
if isinstance(unit_system, UnitSystem):
return unit_system
if unit_system not in UnitSystem._unit_systems:
raise ValueError(
"Unit system is not supported. Currently"
"supported unit systems are {}".format(
", ".join(sorted(UnitSystem._unit_systems))
)
)
return UnitSystem._unit_systems[unit_system]
@staticmethod
def get_default_unit_system():
return UnitSystem._unit_systems["SI"]
@property
def dim(self):
"""
Give the dimension of the system.
That is return the number of units forming the basis.
"""
return len(self._base_units)
@property
def is_consistent(self):
"""
Check if the underlying dimension system is consistent.
"""
# test is performed in DimensionSystem
return self.get_dimension_system().is_consistent
@property
def derived_units(self) -> tDict[Dimension, Quantity]:
return self._derived_units
def get_dimensional_expr(self, expr):
from sympy.physics.units import Quantity
if isinstance(expr, Mul):
return Mul(*[self.get_dimensional_expr(i) for i in expr.args])
elif isinstance(expr, Pow):
return self.get_dimensional_expr(expr.base) ** expr.exp
elif isinstance(expr, Add):
return self.get_dimensional_expr(expr.args[0])
elif isinstance(expr, Derivative):
dim = self.get_dimensional_expr(expr.expr)
for independent, count in expr.variable_count:
dim /= self.get_dimensional_expr(independent)**count
return dim
elif isinstance(expr, Function):
args = [self.get_dimensional_expr(arg) for arg in expr.args]
if all(i == 1 for i in args):
return S.One
return expr.func(*args)
elif isinstance(expr, Quantity):
return self.get_quantity_dimension(expr).name
return S.One
def _collect_factor_and_dimension(self, expr):
"""
Return tuple with scale factor expression and dimension expression.
"""
from sympy.physics.units import Quantity
if isinstance(expr, Quantity):
return expr.scale_factor, expr.dimension
elif isinstance(expr, Mul):
factor = 1
dimension = Dimension(1)
for arg in expr.args:
arg_factor, arg_dim = self._collect_factor_and_dimension(arg)
factor *= arg_factor
dimension *= arg_dim
return factor, dimension
elif isinstance(expr, Pow):
factor, dim = self._collect_factor_and_dimension(expr.base)
exp_factor, exp_dim = self._collect_factor_and_dimension(expr.exp)
if self.get_dimension_system().is_dimensionless(exp_dim):
exp_dim = 1
return factor ** exp_factor, dim ** (exp_factor * exp_dim)
elif isinstance(expr, Add):
factor, dim = self._collect_factor_and_dimension(expr.args[0])
for addend in expr.args[1:]:
addend_factor, addend_dim = \
self._collect_factor_and_dimension(addend)
if not self.get_dimension_system().equivalent_dims(dim, addend_dim):
raise ValueError(
'Dimension of "{}" is {}, '
'but it should be {}'.format(
addend, addend_dim, dim))
factor += addend_factor
return factor, dim
elif isinstance(expr, Derivative):
factor, dim = self._collect_factor_and_dimension(expr.args[0])
for independent, count in expr.variable_count:
ifactor, idim = self._collect_factor_and_dimension(independent)
factor /= ifactor**count
dim /= idim**count
return factor, dim
elif isinstance(expr, Function):
fds = [self._collect_factor_and_dimension(arg) for arg in expr.args]
dims = [Dimension(1) if self.get_dimension_system().is_dimensionless(d[1]) else d[1] for d in fds]
return (expr.func(*(f[0] for f in fds)), *dims)
elif isinstance(expr, Dimension):
return S.One, expr
else:
return expr, Dimension(1)
def get_units_non_prefixed(self) -> tSet[Quantity]:
"""
Return the units of the system that do not have a prefix.
"""
return set(filter(lambda u: not u.is_prefixed and not u.is_physical_constant, self._units))
PK ]ZZZ+)�& �& sympy/physics/units/util.py"""
Several methods to simplify expressions involving unit objects.
"""
from functools import reduce
from collections.abc import Iterable
from typing import Optional
from sympy import default_sort_key
from sympy.core.add import Add
from sympy.core.containers import Tuple
from sympy.core.mul import Mul
from sympy.core.power import Pow
from sympy.core.sorting import ordered
from sympy.core.sympify import sympify
from sympy.core.function import Function
from sympy.matrices.exceptions import NonInvertibleMatrixError
from sympy.physics.units.dimensions import Dimension, DimensionSystem
from sympy.physics.units.prefixes import Prefix
from sympy.physics.units.quantities import Quantity
from sympy.physics.units.unitsystem import UnitSystem
from sympy.utilities.iterables import sift
def _get_conversion_matrix_for_expr(expr, target_units, unit_system):
from sympy.matrices.dense import Matrix
dimension_system = unit_system.get_dimension_system()
expr_dim = Dimension(unit_system.get_dimensional_expr(expr))
dim_dependencies = dimension_system.get_dimensional_dependencies(expr_dim, mark_dimensionless=True)
target_dims = [Dimension(unit_system.get_dimensional_expr(x)) for x in target_units]
canon_dim_units = [i for x in target_dims for i in dimension_system.get_dimensional_dependencies(x, mark_dimensionless=True)]
canon_expr_units = set(dim_dependencies)
if not canon_expr_units.issubset(set(canon_dim_units)):
return None
seen = set()
canon_dim_units = [i for i in canon_dim_units if not (i in seen or seen.add(i))]
camat = Matrix([[dimension_system.get_dimensional_dependencies(i, mark_dimensionless=True).get(j, 0) for i in target_dims] for j in canon_dim_units])
exprmat = Matrix([dim_dependencies.get(k, 0) for k in canon_dim_units])
try:
res_exponents = camat.solve(exprmat)
except NonInvertibleMatrixError:
return None
return res_exponents
def convert_to(expr, target_units, unit_system="SI"):
"""
Convert ``expr`` to the same expression with all of its units and quantities
represented as factors of ``target_units``, whenever the dimension is compatible.
``target_units`` may be a single unit/quantity, or a collection of
units/quantities.
Examples
========
>>> from sympy.physics.units import speed_of_light, meter, gram, second, day
>>> from sympy.physics.units import mile, newton, kilogram, atomic_mass_constant
>>> from sympy.physics.units import kilometer, centimeter
>>> from sympy.physics.units import gravitational_constant, hbar
>>> from sympy.physics.units import convert_to
>>> convert_to(mile, kilometer)
25146*kilometer/15625
>>> convert_to(mile, kilometer).n()
1.609344*kilometer
>>> convert_to(speed_of_light, meter/second)
299792458*meter/second
>>> convert_to(day, second)
86400*second
>>> 3*newton
3*newton
>>> convert_to(3*newton, kilogram*meter/second**2)
3*kilogram*meter/second**2
>>> convert_to(atomic_mass_constant, gram)
1.660539060e-24*gram
Conversion to multiple units:
>>> convert_to(speed_of_light, [meter, second])
299792458*meter/second
>>> convert_to(3*newton, [centimeter, gram, second])
300000*centimeter*gram/second**2
Conversion to Planck units:
>>> convert_to(atomic_mass_constant, [gravitational_constant, speed_of_light, hbar]).n()
7.62963087839509e-20*hbar**0.5*speed_of_light**0.5/gravitational_constant**0.5
"""
from sympy.physics.units import UnitSystem
unit_system = UnitSystem.get_unit_system(unit_system)
if not isinstance(target_units, (Iterable, Tuple)):
target_units = [target_units]
def handle_Adds(expr):
return Add.fromiter(convert_to(i, target_units, unit_system)
for i in expr.args)
if isinstance(expr, Add):
return handle_Adds(expr)
elif isinstance(expr, Pow) and isinstance(expr.base, Add):
return handle_Adds(expr.base) ** expr.exp
expr = sympify(expr)
target_units = sympify(target_units)
if isinstance(expr, Function):
expr = expr.together()
if not isinstance(expr, Quantity) and expr.has(Quantity):
expr = expr.replace(lambda x: isinstance(x, Quantity),
lambda x: x.convert_to(target_units, unit_system))
def get_total_scale_factor(expr):
if isinstance(expr, Mul):
return reduce(lambda x, y: x * y,
[get_total_scale_factor(i) for i in expr.args])
elif isinstance(expr, Pow):
return get_total_scale_factor(expr.base) ** expr.exp
elif isinstance(expr, Quantity):
return unit_system.get_quantity_scale_factor(expr)
return expr
depmat = _get_conversion_matrix_for_expr(expr, target_units, unit_system)
if depmat is None:
return expr
expr_scale_factor = get_total_scale_factor(expr)
return expr_scale_factor * Mul.fromiter(
(1/get_total_scale_factor(u)*u)**p for u, p in
zip(target_units, depmat))
def quantity_simplify(expr, across_dimensions: bool=False, unit_system=None):
"""Return an equivalent expression in which prefixes are replaced
with numerical values and all units of a given dimension are the
unified in a canonical manner by default. `across_dimensions` allows
for units of different dimensions to be simplified together.
`unit_system` must be specified if `across_dimensions` is True.
Examples
========
>>> from sympy.physics.units.util import quantity_simplify
>>> from sympy.physics.units.prefixes import kilo
>>> from sympy.physics.units import foot, inch, joule, coulomb
>>> quantity_simplify(kilo*foot*inch)
250*foot**2/3
>>> quantity_simplify(foot - 6*inch)
foot/2
>>> quantity_simplify(5*joule/coulomb, across_dimensions=True, unit_system="SI")
5*volt
"""
if expr.is_Atom or not expr.has(Prefix, Quantity):
return expr
# replace all prefixes with numerical values
p = expr.atoms(Prefix)
expr = expr.xreplace({p: p.scale_factor for p in p})
# replace all quantities of given dimension with a canonical
# quantity, chosen from those in the expression
d = sift(expr.atoms(Quantity), lambda i: i.dimension)
for k in d:
if len(d[k]) == 1:
continue
v = list(ordered(d[k]))
ref = v[0]/v[0].scale_factor
expr = expr.xreplace({vi: ref*vi.scale_factor for vi in v[1:]})
if across_dimensions:
# combine quantities of different dimensions into a single
# quantity that is equivalent to the original expression
if unit_system is None:
raise ValueError("unit_system must be specified if across_dimensions is True")
unit_system = UnitSystem.get_unit_system(unit_system)
dimension_system: DimensionSystem = unit_system.get_dimension_system()
dim_expr = unit_system.get_dimensional_expr(expr)
dim_deps = dimension_system.get_dimensional_dependencies(dim_expr, mark_dimensionless=True)
target_dimension: Optional[Dimension] = None
for ds_dim, ds_dim_deps in dimension_system.dimensional_dependencies.items():
if ds_dim_deps == dim_deps:
target_dimension = ds_dim
break
if target_dimension is None:
# if we can't find a target dimension, we can't do anything. unsure how to handle this case.
return expr
target_unit = unit_system.derived_units.get(target_dimension)
if target_unit:
expr = convert_to(expr, target_unit, unit_system)
return expr
def check_dimensions(expr, unit_system="SI"):
"""Return expr if units in addends have the same
base dimensions, else raise a ValueError."""
# the case of adding a number to a dimensional quantity
# is ignored for the sake of SymPy core routines, so this
# function will raise an error now if such an addend is
# found.
# Also, when doing substitutions, multiplicative constants
# might be introduced, so remove those now
from sympy.physics.units import UnitSystem
unit_system = UnitSystem.get_unit_system(unit_system)
def addDict(dict1, dict2):
"""Merge dictionaries by adding values of common keys and
removing keys with value of 0."""
dict3 = {**dict1, **dict2}
for key, value in dict3.items():
if key in dict1 and key in dict2:
dict3[key] = value + dict1[key]
return {key:val for key, val in dict3.items() if val != 0}
adds = expr.atoms(Add)
DIM_OF = unit_system.get_dimension_system().get_dimensional_dependencies
for a in adds:
deset = set()
for ai in a.args:
if ai.is_number:
deset.add(())
continue
dims = []
skip = False
dimdict = {}
for i in Mul.make_args(ai):
if i.has(Quantity):
i = Dimension(unit_system.get_dimensional_expr(i))
if i.has(Dimension):
dimdict = addDict(dimdict, DIM_OF(i))
elif i.free_symbols:
skip = True
break
dims.extend(dimdict.items())
if not skip:
deset.add(tuple(sorted(dims, key=default_sort_key)))
if len(deset) > 1:
raise ValueError(
"addends have incompatible dimensions: {}".format(deset))
# clear multiplicative constants on Dimensions which may be
# left after substitution
reps = {}
for m in expr.atoms(Mul):
if any(isinstance(i, Dimension) for i in m.args):
reps[m] = m.func(*[
i for i in m.args if not i.is_number])
return expr.xreplace(reps)
PK ]ZZZҍۗ. . + sympy/physics/units/definitions/__init__.pyfrom .unit_definitions import (
percent, percents,
permille,
rad, radian, radians,
deg, degree, degrees,
sr, steradian, steradians,
mil, angular_mil, angular_mils,
m, meter, meters,
kg, kilogram, kilograms,
s, second, seconds,
A, ampere, amperes,
K, kelvin, kelvins,
mol, mole, moles,
cd, candela, candelas,
g, gram, grams,
mg, milligram, milligrams,
ug, microgram, micrograms,
t, tonne, metric_ton,
newton, newtons, N,
joule, joules, J,
watt, watts, W,
pascal, pascals, Pa, pa,
hertz, hz, Hz,
coulomb, coulombs, C,
volt, volts, v, V,
ohm, ohms,
siemens, S, mho, mhos,
farad, farads, F,
henry, henrys, H,
tesla, teslas, T,
weber, webers, Wb, wb,
optical_power, dioptre, D,
lux, lx,
katal, kat,
gray, Gy,
becquerel, Bq,
km, kilometer, kilometers,
dm, decimeter, decimeters,
cm, centimeter, centimeters,
mm, millimeter, millimeters,
um, micrometer, micrometers, micron, microns,
nm, nanometer, nanometers,
pm, picometer, picometers,
ft, foot, feet,
inch, inches,
yd, yard, yards,
mi, mile, miles,
nmi, nautical_mile, nautical_miles,
ha, hectare,
l, L, liter, liters,
dl, dL, deciliter, deciliters,
cl, cL, centiliter, centiliters,
ml, mL, milliliter, milliliters,
ms, millisecond, milliseconds,
us, microsecond, microseconds,
ns, nanosecond, nanoseconds,
ps, picosecond, picoseconds,
minute, minutes,
h, hour, hours,
day, days,
anomalistic_year, anomalistic_years,
sidereal_year, sidereal_years,
tropical_year, tropical_years,
common_year, common_years,
julian_year, julian_years,
draconic_year, draconic_years,
gaussian_year, gaussian_years,
full_moon_cycle, full_moon_cycles,
year, years,
G, gravitational_constant,
c, speed_of_light,
elementary_charge,
hbar,
planck,
eV, electronvolt, electronvolts,
avogadro_number,
avogadro, avogadro_constant,
boltzmann, boltzmann_constant,
stefan, stefan_boltzmann_constant,
R, molar_gas_constant,
faraday_constant,
josephson_constant,
von_klitzing_constant,
Da, dalton, amu, amus, atomic_mass_unit, atomic_mass_constant,
me, electron_rest_mass,
gee, gees, acceleration_due_to_gravity,
u0, magnetic_constant, vacuum_permeability,
e0, electric_constant, vacuum_permittivity,
Z0, vacuum_impedance,
coulomb_constant, coulombs_constant, electric_force_constant,
atmosphere, atmospheres, atm,
kPa, kilopascal,
bar, bars,
pound, pounds,
psi,
dHg0,
mmHg, torr,
mmu, mmus, milli_mass_unit,
quart, quarts,
angstrom, angstroms,
ly, lightyear, lightyears,
au, astronomical_unit, astronomical_units,
planck_mass,
planck_time,
planck_temperature,
planck_length,
planck_charge,
planck_area,
planck_volume,
planck_momentum,
planck_energy,
planck_force,
planck_power,
planck_density,
planck_energy_density,
planck_intensity,
planck_angular_frequency,
planck_pressure,
planck_current,
planck_voltage,
planck_impedance,
planck_acceleration,
bit, bits,
byte,
kibibyte, kibibytes,
mebibyte, mebibytes,
gibibyte, gibibytes,
tebibyte, tebibytes,
pebibyte, pebibytes,
exbibyte, exbibytes,
curie, rutherford
)
__all__ = [
'percent', 'percents',
'permille',
'rad', 'radian', 'radians',
'deg', 'degree', 'degrees',
'sr', 'steradian', 'steradians',
'mil', 'angular_mil', 'angular_mils',
'm', 'meter', 'meters',
'kg', 'kilogram', 'kilograms',
's', 'second', 'seconds',
'A', 'ampere', 'amperes',
'K', 'kelvin', 'kelvins',
'mol', 'mole', 'moles',
'cd', 'candela', 'candelas',
'g', 'gram', 'grams',
'mg', 'milligram', 'milligrams',
'ug', 'microgram', 'micrograms',
't', 'tonne', 'metric_ton',
'newton', 'newtons', 'N',
'joule', 'joules', 'J',
'watt', 'watts', 'W',
'pascal', 'pascals', 'Pa', 'pa',
'hertz', 'hz', 'Hz',
'coulomb', 'coulombs', 'C',
'volt', 'volts', 'v', 'V',
'ohm', 'ohms',
'siemens', 'S', 'mho', 'mhos',
'farad', 'farads', 'F',
'henry', 'henrys', 'H',
'tesla', 'teslas', 'T',
'weber', 'webers', 'Wb', 'wb',
'optical_power', 'dioptre', 'D',
'lux', 'lx',
'katal', 'kat',
'gray', 'Gy',
'becquerel', 'Bq',
'km', 'kilometer', 'kilometers',
'dm', 'decimeter', 'decimeters',
'cm', 'centimeter', 'centimeters',
'mm', 'millimeter', 'millimeters',
'um', 'micrometer', 'micrometers', 'micron', 'microns',
'nm', 'nanometer', 'nanometers',
'pm', 'picometer', 'picometers',
'ft', 'foot', 'feet',
'inch', 'inches',
'yd', 'yard', 'yards',
'mi', 'mile', 'miles',
'nmi', 'nautical_mile', 'nautical_miles',
'ha', 'hectare',
'l', 'L', 'liter', 'liters',
'dl', 'dL', 'deciliter', 'deciliters',
'cl', 'cL', 'centiliter', 'centiliters',
'ml', 'mL', 'milliliter', 'milliliters',
'ms', 'millisecond', 'milliseconds',
'us', 'microsecond', 'microseconds',
'ns', 'nanosecond', 'nanoseconds',
'ps', 'picosecond', 'picoseconds',
'minute', 'minutes',
'h', 'hour', 'hours',
'day', 'days',
'anomalistic_year', 'anomalistic_years',
'sidereal_year', 'sidereal_years',
'tropical_year', 'tropical_years',
'common_year', 'common_years',
'julian_year', 'julian_years',
'draconic_year', 'draconic_years',
'gaussian_year', 'gaussian_years',
'full_moon_cycle', 'full_moon_cycles',
'year', 'years',
'G', 'gravitational_constant',
'c', 'speed_of_light',
'elementary_charge',
'hbar',
'planck',
'eV', 'electronvolt', 'electronvolts',
'avogadro_number',
'avogadro', 'avogadro_constant',
'boltzmann', 'boltzmann_constant',
'stefan', 'stefan_boltzmann_constant',
'R', 'molar_gas_constant',
'faraday_constant',
'josephson_constant',
'von_klitzing_constant',
'Da', 'dalton', 'amu', 'amus', 'atomic_mass_unit', 'atomic_mass_constant',
'me', 'electron_rest_mass',
'gee', 'gees', 'acceleration_due_to_gravity',
'u0', 'magnetic_constant', 'vacuum_permeability',
'e0', 'electric_constant', 'vacuum_permittivity',
'Z0', 'vacuum_impedance',
'coulomb_constant', 'coulombs_constant', 'electric_force_constant',
'atmosphere', 'atmospheres', 'atm',
'kPa', 'kilopascal',
'bar', 'bars',
'pound', 'pounds',
'psi',
'dHg0',
'mmHg', 'torr',
'mmu', 'mmus', 'milli_mass_unit',
'quart', 'quarts',
'angstrom', 'angstroms',
'ly', 'lightyear', 'lightyears',
'au', 'astronomical_unit', 'astronomical_units',
'planck_mass',
'planck_time',
'planck_temperature',
'planck_length',
'planck_charge',
'planck_area',
'planck_volume',
'planck_momentum',
'planck_energy',
'planck_force',
'planck_power',
'planck_density',
'planck_energy_density',
'planck_intensity',
'planck_angular_frequency',
'planck_pressure',
'planck_current',
'planck_voltage',
'planck_impedance',
'planck_acceleration',
'bit', 'bits',
'byte',
'kibibyte', 'kibibytes',
'mebibyte', 'mebibytes',
'gibibyte', 'gibibytes',
'tebibyte', 'tebibytes',
'pebibyte', 'pebibytes',
'exbibyte', 'exbibytes',
'curie', 'rutherford',
]
PK ]ZZZ�> �� � 8 sympy/physics/units/definitions/dimension_definitions.pyfrom sympy.physics.units import Dimension
angle = Dimension(name="angle") # type: Dimension
# base dimensions (MKS)
length = Dimension(name="length", symbol="L")
mass = Dimension(name="mass", symbol="M")
time = Dimension(name="time", symbol="T")
# base dimensions (MKSA not in MKS)
current = Dimension(name='current', symbol='I') # type: Dimension
# other base dimensions:
temperature = Dimension("temperature", "T") # type: Dimension
amount_of_substance = Dimension("amount_of_substance") # type: Dimension
luminous_intensity = Dimension("luminous_intensity") # type: Dimension
# derived dimensions (MKS)
velocity = Dimension(name="velocity")
acceleration = Dimension(name="acceleration")
momentum = Dimension(name="momentum")
force = Dimension(name="force", symbol="F")
energy = Dimension(name="energy", symbol="E")
power = Dimension(name="power")
pressure = Dimension(name="pressure")
frequency = Dimension(name="frequency", symbol="f")
action = Dimension(name="action", symbol="A")
area = Dimension("area")
volume = Dimension("volume")
# derived dimensions (MKSA not in MKS)
voltage = Dimension(name='voltage', symbol='U') # type: Dimension
impedance = Dimension(name='impedance', symbol='Z') # type: Dimension
conductance = Dimension(name='conductance', symbol='G') # type: Dimension
capacitance = Dimension(name='capacitance') # type: Dimension
inductance = Dimension(name='inductance') # type: Dimension
charge = Dimension(name='charge', symbol='Q') # type: Dimension
magnetic_density = Dimension(name='magnetic_density', symbol='B') # type: Dimension
magnetic_flux = Dimension(name='magnetic_flux') # type: Dimension
# Dimensions in information theory:
information = Dimension(name='information') # type: Dimension
PK ]ZZZ% 5NX9 X9 3 sympy/physics/units/definitions/unit_definitions.pyfrom sympy.physics.units.definitions.dimension_definitions import current, temperature, amount_of_substance, \
luminous_intensity, angle, charge, voltage, impedance, conductance, capacitance, inductance, magnetic_density, \
magnetic_flux, information
from sympy.core.numbers import (Rational, pi)
from sympy.core.singleton import S as S_singleton
from sympy.physics.units.prefixes import kilo, mega, milli, micro, deci, centi, nano, pico, kibi, mebi, gibi, tebi, pebi, exbi
from sympy.physics.units.quantities import PhysicalConstant, Quantity
One = S_singleton.One
#### UNITS ####
# Dimensionless:
percent = percents = Quantity("percent", latex_repr=r"\%")
percent.set_global_relative_scale_factor(Rational(1, 100), One)
permille = Quantity("permille")
permille.set_global_relative_scale_factor(Rational(1, 1000), One)
# Angular units (dimensionless)
rad = radian = radians = Quantity("radian", abbrev="rad")
radian.set_global_dimension(angle)
deg = degree = degrees = Quantity("degree", abbrev="deg", latex_repr=r"^\circ")
degree.set_global_relative_scale_factor(pi/180, radian)
sr = steradian = steradians = Quantity("steradian", abbrev="sr")
mil = angular_mil = angular_mils = Quantity("angular_mil", abbrev="mil")
# Base units:
m = meter = meters = Quantity("meter", abbrev="m")
# gram; used to define its prefixed units
g = gram = grams = Quantity("gram", abbrev="g")
# NOTE: the `kilogram` has scale factor 1000. In SI, kg is a base unit, but
# nonetheless we are trying to be compatible with the `kilo` prefix. In a
# similar manner, people using CGS or gaussian units could argue that the
# `centimeter` rather than `meter` is the fundamental unit for length, but the
# scale factor of `centimeter` will be kept as 1/100 to be compatible with the
# `centi` prefix. The current state of the code assumes SI unit dimensions, in
# the future this module will be modified in order to be unit system-neutral
# (that is, support all kinds of unit systems).
kg = kilogram = kilograms = Quantity("kilogram", abbrev="kg")
kg.set_global_relative_scale_factor(kilo, gram)
s = second = seconds = Quantity("second", abbrev="s")
A = ampere = amperes = Quantity("ampere", abbrev='A')
ampere.set_global_dimension(current)
K = kelvin = kelvins = Quantity("kelvin", abbrev='K')
kelvin.set_global_dimension(temperature)
mol = mole = moles = Quantity("mole", abbrev="mol")
mole.set_global_dimension(amount_of_substance)
cd = candela = candelas = Quantity("candela", abbrev="cd")
candela.set_global_dimension(luminous_intensity)
# derived units
newton = newtons = N = Quantity("newton", abbrev="N")
kilonewton = kilonewtons = kN = Quantity("kilonewton", abbrev="kN")
kilonewton.set_global_relative_scale_factor(kilo, newton)
meganewton = meganewtons = MN = Quantity("meganewton", abbrev="MN")
meganewton.set_global_relative_scale_factor(mega, newton)
joule = joules = J = Quantity("joule", abbrev="J")
watt = watts = W = Quantity("watt", abbrev="W")
pascal = pascals = Pa = pa = Quantity("pascal", abbrev="Pa")
hertz = hz = Hz = Quantity("hertz", abbrev="Hz")
# CGS derived units:
dyne = Quantity("dyne")
dyne.set_global_relative_scale_factor(One/10**5, newton)
erg = Quantity("erg")
erg.set_global_relative_scale_factor(One/10**7, joule)
# MKSA extension to MKS: derived units
coulomb = coulombs = C = Quantity("coulomb", abbrev='C')
coulomb.set_global_dimension(charge)
volt = volts = v = V = Quantity("volt", abbrev='V')
volt.set_global_dimension(voltage)
ohm = ohms = Quantity("ohm", abbrev='ohm', latex_repr=r"\Omega")
ohm.set_global_dimension(impedance)
siemens = S = mho = mhos = Quantity("siemens", abbrev='S')
siemens.set_global_dimension(conductance)
farad = farads = F = Quantity("farad", abbrev='F')
farad.set_global_dimension(capacitance)
henry = henrys = H = Quantity("henry", abbrev='H')
henry.set_global_dimension(inductance)
tesla = teslas = T = Quantity("tesla", abbrev='T')
tesla.set_global_dimension(magnetic_density)
weber = webers = Wb = wb = Quantity("weber", abbrev='Wb')
weber.set_global_dimension(magnetic_flux)
# CGS units for electromagnetic quantities:
statampere = Quantity("statampere")
statcoulomb = statC = franklin = Quantity("statcoulomb", abbrev="statC")
statvolt = Quantity("statvolt")
gauss = Quantity("gauss")
maxwell = Quantity("maxwell")
debye = Quantity("debye")
oersted = Quantity("oersted")
# Other derived units:
optical_power = dioptre = diopter = D = Quantity("dioptre")
lux = lx = Quantity("lux", abbrev="lx")
# katal is the SI unit of catalytic activity
katal = kat = Quantity("katal", abbrev="kat")
# gray is the SI unit of absorbed dose
gray = Gy = Quantity("gray")
# becquerel is the SI unit of radioactivity
becquerel = Bq = Quantity("becquerel", abbrev="Bq")
# Common mass units
mg = milligram = milligrams = Quantity("milligram", abbrev="mg")
mg.set_global_relative_scale_factor(milli, gram)
ug = microgram = micrograms = Quantity("microgram", abbrev="ug", latex_repr=r"\mu\text{g}")
ug.set_global_relative_scale_factor(micro, gram)
# Atomic mass constant
Da = dalton = amu = amus = atomic_mass_unit = atomic_mass_constant = PhysicalConstant("atomic_mass_constant")
t = metric_ton = tonne = Quantity("tonne", abbrev="t")
tonne.set_global_relative_scale_factor(mega, gram)
# Electron rest mass
me = electron_rest_mass = Quantity("electron_rest_mass", abbrev="me")
# Common length units
km = kilometer = kilometers = Quantity("kilometer", abbrev="km")
km.set_global_relative_scale_factor(kilo, meter)
dm = decimeter = decimeters = Quantity("decimeter", abbrev="dm")
dm.set_global_relative_scale_factor(deci, meter)
cm = centimeter = centimeters = Quantity("centimeter", abbrev="cm")
cm.set_global_relative_scale_factor(centi, meter)
mm = millimeter = millimeters = Quantity("millimeter", abbrev="mm")
mm.set_global_relative_scale_factor(milli, meter)
um = micrometer = micrometers = micron = microns = \
Quantity("micrometer", abbrev="um", latex_repr=r'\mu\text{m}')
um.set_global_relative_scale_factor(micro, meter)
nm = nanometer = nanometers = Quantity("nanometer", abbrev="nm")
nm.set_global_relative_scale_factor(nano, meter)
pm = picometer = picometers = Quantity("picometer", abbrev="pm")
pm.set_global_relative_scale_factor(pico, meter)
ft = foot = feet = Quantity("foot", abbrev="ft")
ft.set_global_relative_scale_factor(Rational(3048, 10000), meter)
inch = inches = Quantity("inch")
inch.set_global_relative_scale_factor(Rational(1, 12), foot)
yd = yard = yards = Quantity("yard", abbrev="yd")
yd.set_global_relative_scale_factor(3, feet)
mi = mile = miles = Quantity("mile")
mi.set_global_relative_scale_factor(5280, feet)
nmi = nautical_mile = nautical_miles = Quantity("nautical_mile")
nmi.set_global_relative_scale_factor(6076, feet)
angstrom = angstroms = Quantity("angstrom", latex_repr=r'\r{A}')
angstrom.set_global_relative_scale_factor(Rational(1, 10**10), meter)
# Common volume and area units
ha = hectare = Quantity("hectare", abbrev="ha")
l = L = liter = liters = Quantity("liter", abbrev="l")
dl = dL = deciliter = deciliters = Quantity("deciliter", abbrev="dl")
dl.set_global_relative_scale_factor(Rational(1, 10), liter)
cl = cL = centiliter = centiliters = Quantity("centiliter", abbrev="cl")
cl.set_global_relative_scale_factor(Rational(1, 100), liter)
ml = mL = milliliter = milliliters = Quantity("milliliter", abbrev="ml")
ml.set_global_relative_scale_factor(Rational(1, 1000), liter)
# Common time units
ms = millisecond = milliseconds = Quantity("millisecond", abbrev="ms")
millisecond.set_global_relative_scale_factor(milli, second)
us = microsecond = microseconds = Quantity("microsecond", abbrev="us", latex_repr=r'\mu\text{s}')
microsecond.set_global_relative_scale_factor(micro, second)
ns = nanosecond = nanoseconds = Quantity("nanosecond", abbrev="ns")
nanosecond.set_global_relative_scale_factor(nano, second)
ps = picosecond = picoseconds = Quantity("picosecond", abbrev="ps")
picosecond.set_global_relative_scale_factor(pico, second)
minute = minutes = Quantity("minute")
minute.set_global_relative_scale_factor(60, second)
h = hour = hours = Quantity("hour")
hour.set_global_relative_scale_factor(60, minute)
day = days = Quantity("day")
day.set_global_relative_scale_factor(24, hour)
anomalistic_year = anomalistic_years = Quantity("anomalistic_year")
anomalistic_year.set_global_relative_scale_factor(365.259636, day)
sidereal_year = sidereal_years = Quantity("sidereal_year")
sidereal_year.set_global_relative_scale_factor(31558149.540, seconds)
tropical_year = tropical_years = Quantity("tropical_year")
tropical_year.set_global_relative_scale_factor(365.24219, day)
common_year = common_years = Quantity("common_year")
common_year.set_global_relative_scale_factor(365, day)
julian_year = julian_years = Quantity("julian_year")
julian_year.set_global_relative_scale_factor((365 + One/4), day)
draconic_year = draconic_years = Quantity("draconic_year")
draconic_year.set_global_relative_scale_factor(346.62, day)
gaussian_year = gaussian_years = Quantity("gaussian_year")
gaussian_year.set_global_relative_scale_factor(365.2568983, day)
full_moon_cycle = full_moon_cycles = Quantity("full_moon_cycle")
full_moon_cycle.set_global_relative_scale_factor(411.78443029, day)
year = years = tropical_year
#### CONSTANTS ####
# Newton constant
G = gravitational_constant = PhysicalConstant("gravitational_constant", abbrev="G")
# speed of light
c = speed_of_light = PhysicalConstant("speed_of_light", abbrev="c")
# elementary charge
elementary_charge = PhysicalConstant("elementary_charge", abbrev="e")
# Planck constant
planck = PhysicalConstant("planck", abbrev="h")
# Reduced Planck constant
hbar = PhysicalConstant("hbar", abbrev="hbar")
# Electronvolt
eV = electronvolt = electronvolts = PhysicalConstant("electronvolt", abbrev="eV")
# Avogadro number
avogadro_number = PhysicalConstant("avogadro_number")
# Avogadro constant
avogadro = avogadro_constant = PhysicalConstant("avogadro_constant")
# Boltzmann constant
boltzmann = boltzmann_constant = PhysicalConstant("boltzmann_constant")
# Stefan-Boltzmann constant
stefan = stefan_boltzmann_constant = PhysicalConstant("stefan_boltzmann_constant")
# Molar gas constant
R = molar_gas_constant = PhysicalConstant("molar_gas_constant", abbrev="R")
# Faraday constant
faraday_constant = PhysicalConstant("faraday_constant")
# Josephson constant
josephson_constant = PhysicalConstant("josephson_constant", abbrev="K_j")
# Von Klitzing constant
von_klitzing_constant = PhysicalConstant("von_klitzing_constant", abbrev="R_k")
# Acceleration due to gravity (on the Earth surface)
gee = gees = acceleration_due_to_gravity = PhysicalConstant("acceleration_due_to_gravity", abbrev="g")
# magnetic constant:
u0 = magnetic_constant = vacuum_permeability = PhysicalConstant("magnetic_constant")
# electric constat:
e0 = electric_constant = vacuum_permittivity = PhysicalConstant("vacuum_permittivity")
# vacuum impedance:
Z0 = vacuum_impedance = PhysicalConstant("vacuum_impedance", abbrev='Z_0', latex_repr=r'Z_{0}')
# Coulomb's constant:
coulomb_constant = coulombs_constant = electric_force_constant = \
PhysicalConstant("coulomb_constant", abbrev="k_e")
atmosphere = atmospheres = atm = Quantity("atmosphere", abbrev="atm")
kPa = kilopascal = Quantity("kilopascal", abbrev="kPa")
kilopascal.set_global_relative_scale_factor(kilo, Pa)
bar = bars = Quantity("bar", abbrev="bar")
pound = pounds = Quantity("pound") # exact
psi = Quantity("psi")
dHg0 = 13.5951 # approx value at 0 C
mmHg = torr = Quantity("mmHg")
atmosphere.set_global_relative_scale_factor(101325, pascal)
bar.set_global_relative_scale_factor(100, kPa)
pound.set_global_relative_scale_factor(Rational(45359237, 100000000), kg)
mmu = mmus = milli_mass_unit = Quantity("milli_mass_unit")
quart = quarts = Quantity("quart")
# Other convenient units and magnitudes
ly = lightyear = lightyears = Quantity("lightyear", abbrev="ly")
au = astronomical_unit = astronomical_units = Quantity("astronomical_unit", abbrev="AU")
# Fundamental Planck units:
planck_mass = Quantity("planck_mass", abbrev="m_P", latex_repr=r'm_\text{P}')
planck_time = Quantity("planck_time", abbrev="t_P", latex_repr=r't_\text{P}')
planck_temperature = Quantity("planck_temperature", abbrev="T_P",
latex_repr=r'T_\text{P}')
planck_length = Quantity("planck_length", abbrev="l_P", latex_repr=r'l_\text{P}')
planck_charge = Quantity("planck_charge", abbrev="q_P", latex_repr=r'q_\text{P}')
# Derived Planck units:
planck_area = Quantity("planck_area")
planck_volume = Quantity("planck_volume")
planck_momentum = Quantity("planck_momentum")
planck_energy = Quantity("planck_energy", abbrev="E_P", latex_repr=r'E_\text{P}')
planck_force = Quantity("planck_force", abbrev="F_P", latex_repr=r'F_\text{P}')
planck_power = Quantity("planck_power", abbrev="P_P", latex_repr=r'P_\text{P}')
planck_density = Quantity("planck_density", abbrev="rho_P", latex_repr=r'\rho_\text{P}')
planck_energy_density = Quantity("planck_energy_density", abbrev="rho^E_P")
planck_intensity = Quantity("planck_intensity", abbrev="I_P", latex_repr=r'I_\text{P}')
planck_angular_frequency = Quantity("planck_angular_frequency", abbrev="omega_P",
latex_repr=r'\omega_\text{P}')
planck_pressure = Quantity("planck_pressure", abbrev="p_P", latex_repr=r'p_\text{P}')
planck_current = Quantity("planck_current", abbrev="I_P", latex_repr=r'I_\text{P}')
planck_voltage = Quantity("planck_voltage", abbrev="V_P", latex_repr=r'V_\text{P}')
planck_impedance = Quantity("planck_impedance", abbrev="Z_P", latex_repr=r'Z_\text{P}')
planck_acceleration = Quantity("planck_acceleration", abbrev="a_P",
latex_repr=r'a_\text{P}')
# Information theory units:
bit = bits = Quantity("bit")
bit.set_global_dimension(information)
byte = bytes = Quantity("byte")
kibibyte = kibibytes = Quantity("kibibyte")
mebibyte = mebibytes = Quantity("mebibyte")
gibibyte = gibibytes = Quantity("gibibyte")
tebibyte = tebibytes = Quantity("tebibyte")
pebibyte = pebibytes = Quantity("pebibyte")
exbibyte = exbibytes = Quantity("exbibyte")
byte.set_global_relative_scale_factor(8, bit)
kibibyte.set_global_relative_scale_factor(kibi, byte)
mebibyte.set_global_relative_scale_factor(mebi, byte)
gibibyte.set_global_relative_scale_factor(gibi, byte)
tebibyte.set_global_relative_scale_factor(tebi, byte)
pebibyte.set_global_relative_scale_factor(pebi, byte)
exbibyte.set_global_relative_scale_factor(exbi, byte)
# Older units for radioactivity
curie = Ci = Quantity("curie", abbrev="Ci")
rutherford = Rd = Quantity("rutherford", abbrev="Rd")
PK ]ZZZ+���� � ' sympy/physics/units/systems/__init__.pyfrom sympy.physics.units.systems.mks import MKS
from sympy.physics.units.systems.mksa import MKSA
from sympy.physics.units.systems.natural import natural
from sympy.physics.units.systems.si import SI
__all__ = ['MKS', 'MKSA', 'natural', 'SI']
PK ]ZZZlM�ev v " sympy/physics/units/systems/cgs.pyfrom sympy.core.singleton import S
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.physics.units import UnitSystem, centimeter, gram, second, coulomb, charge, speed_of_light, current, mass, \
length, voltage, magnetic_density, magnetic_flux
from sympy.physics.units.definitions import coulombs_constant
from sympy.physics.units.definitions.unit_definitions import statcoulomb, statampere, statvolt, volt, tesla, gauss, \
weber, maxwell, debye, oersted, ohm, farad, henry, erg, ampere, coulomb_constant
from sympy.physics.units.systems.mks import dimsys_length_weight_time
One = S.One
dimsys_cgs = dimsys_length_weight_time.extend(
[],
new_dim_deps={
# Dimensional dependencies for derived dimensions
"impedance": {"time": 1, "length": -1},
"conductance": {"time": -1, "length": 1},
"capacitance": {"length": 1},
"inductance": {"time": 2, "length": -1},
"charge": {"mass": S.Half, "length": S(3)/2, "time": -1},
"current": {"mass": One/2, "length": 3*One/2, "time": -2},
"voltage": {"length": -One/2, "mass": One/2, "time": -1},
"magnetic_density": {"length": -One/2, "mass": One/2, "time": -1},
"magnetic_flux": {"length": 3*One/2, "mass": One/2, "time": -1},
}
)
cgs_gauss = UnitSystem(
base_units=[centimeter, gram, second],
units=[],
name="cgs_gauss",
dimension_system=dimsys_cgs)
cgs_gauss.set_quantity_scale_factor(coulombs_constant, 1)
cgs_gauss.set_quantity_dimension(statcoulomb, charge)
cgs_gauss.set_quantity_scale_factor(statcoulomb, centimeter**(S(3)/2)*gram**(S.Half)/second)
cgs_gauss.set_quantity_dimension(coulomb, charge)
cgs_gauss.set_quantity_dimension(statampere, current)
cgs_gauss.set_quantity_scale_factor(statampere, statcoulomb/second)
cgs_gauss.set_quantity_dimension(statvolt, voltage)
cgs_gauss.set_quantity_scale_factor(statvolt, erg/statcoulomb)
cgs_gauss.set_quantity_dimension(volt, voltage)
cgs_gauss.set_quantity_dimension(gauss, magnetic_density)
cgs_gauss.set_quantity_scale_factor(gauss, sqrt(gram/centimeter)/second)
cgs_gauss.set_quantity_dimension(tesla, magnetic_density)
cgs_gauss.set_quantity_dimension(maxwell, magnetic_flux)
cgs_gauss.set_quantity_scale_factor(maxwell, sqrt(centimeter**3*gram)/second)
# SI units expressed in CGS-gaussian units:
cgs_gauss.set_quantity_scale_factor(coulomb, 10*speed_of_light*statcoulomb)
cgs_gauss.set_quantity_scale_factor(ampere, 10*speed_of_light*statcoulomb/second)
cgs_gauss.set_quantity_scale_factor(volt, 10**6/speed_of_light*statvolt)
cgs_gauss.set_quantity_scale_factor(weber, 10**8*maxwell)
cgs_gauss.set_quantity_scale_factor(tesla, 10**4*gauss)
cgs_gauss.set_quantity_scale_factor(debye, One/10**18*statcoulomb*centimeter)
cgs_gauss.set_quantity_scale_factor(oersted, sqrt(gram/centimeter)/second)
cgs_gauss.set_quantity_scale_factor(ohm, 10**5/speed_of_light**2*second/centimeter)
cgs_gauss.set_quantity_scale_factor(farad, One/10**5*speed_of_light**2*centimeter)
cgs_gauss.set_quantity_scale_factor(henry, 10**5/speed_of_light**2/centimeter*second**2)
# Coulomb's constant:
cgs_gauss.set_quantity_dimension(coulomb_constant, 1)
cgs_gauss.set_quantity_scale_factor(coulomb_constant, 1)
__all__ = [
'ohm', 'tesla', 'maxwell', 'speed_of_light', 'volt', 'second', 'voltage',
'debye', 'dimsys_length_weight_time', 'centimeter', 'coulomb_constant',
'farad', 'sqrt', 'UnitSystem', 'current', 'charge', 'weber', 'gram',
'statcoulomb', 'gauss', 'S', 'statvolt', 'oersted', 'statampere',
'dimsys_cgs', 'coulomb', 'magnetic_density', 'magnetic_flux', 'One',
'length', 'erg', 'mass', 'coulombs_constant', 'henry', 'ampere',
'cgs_gauss',
]
PK ]ZZZ:�iz\ \ 1 sympy/physics/units/systems/length_weight_time.pyfrom sympy.core.singleton import S
from sympy.core.numbers import pi
from sympy.physics.units import DimensionSystem, hertz, kilogram
from sympy.physics.units.definitions import (
G, Hz, J, N, Pa, W, c, g, kg, m, s, meter, gram, second, newton,
joule, watt, pascal)
from sympy.physics.units.definitions.dimension_definitions import (
acceleration, action, energy, force, frequency, momentum,
power, pressure, velocity, length, mass, time)
from sympy.physics.units.prefixes import PREFIXES, prefix_unit
from sympy.physics.units.prefixes import (
kibi, mebi, gibi, tebi, pebi, exbi
)
from sympy.physics.units.definitions import (
cd, K, coulomb, volt, ohm, siemens, farad, henry, tesla, weber, dioptre,
lux, katal, gray, becquerel, inch, hectare, liter, julian_year,
gravitational_constant, speed_of_light, elementary_charge, planck, hbar,
electronvolt, avogadro_number, avogadro_constant, boltzmann_constant,
stefan_boltzmann_constant, atomic_mass_constant, molar_gas_constant,
faraday_constant, josephson_constant, von_klitzing_constant,
acceleration_due_to_gravity, magnetic_constant, vacuum_permittivity,
vacuum_impedance, coulomb_constant, atmosphere, bar, pound, psi, mmHg,
milli_mass_unit, quart, lightyear, astronomical_unit, planck_mass,
planck_time, planck_temperature, planck_length, planck_charge,
planck_area, planck_volume, planck_momentum, planck_energy, planck_force,
planck_power, planck_density, planck_energy_density, planck_intensity,
planck_angular_frequency, planck_pressure, planck_current, planck_voltage,
planck_impedance, planck_acceleration, bit, byte, kibibyte, mebibyte,
gibibyte, tebibyte, pebibyte, exbibyte, curie, rutherford, radian, degree,
steradian, angular_mil, atomic_mass_unit, gee, kPa, ampere, u0, kelvin,
mol, mole, candela, electric_constant, boltzmann, angstrom
)
dimsys_length_weight_time = DimensionSystem([
# Dimensional dependencies for MKS base dimensions
length,
mass,
time,
], dimensional_dependencies={
# Dimensional dependencies for derived dimensions
"velocity": {"length": 1, "time": -1},
"acceleration": {"length": 1, "time": -2},
"momentum": {"mass": 1, "length": 1, "time": -1},
"force": {"mass": 1, "length": 1, "time": -2},
"energy": {"mass": 1, "length": 2, "time": -2},
"power": {"length": 2, "mass": 1, "time": -3},
"pressure": {"mass": 1, "length": -1, "time": -2},
"frequency": {"time": -1},
"action": {"length": 2, "mass": 1, "time": -1},
"area": {"length": 2},
"volume": {"length": 3},
})
One = S.One
# Base units:
dimsys_length_weight_time.set_quantity_dimension(meter, length)
dimsys_length_weight_time.set_quantity_scale_factor(meter, One)
# gram; used to define its prefixed units
dimsys_length_weight_time.set_quantity_dimension(gram, mass)
dimsys_length_weight_time.set_quantity_scale_factor(gram, One)
dimsys_length_weight_time.set_quantity_dimension(second, time)
dimsys_length_weight_time.set_quantity_scale_factor(second, One)
# derived units
dimsys_length_weight_time.set_quantity_dimension(newton, force)
dimsys_length_weight_time.set_quantity_scale_factor(newton, kilogram*meter/second**2)
dimsys_length_weight_time.set_quantity_dimension(joule, energy)
dimsys_length_weight_time.set_quantity_scale_factor(joule, newton*meter)
dimsys_length_weight_time.set_quantity_dimension(watt, power)
dimsys_length_weight_time.set_quantity_scale_factor(watt, joule/second)
dimsys_length_weight_time.set_quantity_dimension(pascal, pressure)
dimsys_length_weight_time.set_quantity_scale_factor(pascal, newton/meter**2)
dimsys_length_weight_time.set_quantity_dimension(hertz, frequency)
dimsys_length_weight_time.set_quantity_scale_factor(hertz, One)
# Other derived units:
dimsys_length_weight_time.set_quantity_dimension(dioptre, 1 / length)
dimsys_length_weight_time.set_quantity_scale_factor(dioptre, 1/meter)
# Common volume and area units
dimsys_length_weight_time.set_quantity_dimension(hectare, length**2)
dimsys_length_weight_time.set_quantity_scale_factor(hectare, (meter**2)*(10000))
dimsys_length_weight_time.set_quantity_dimension(liter, length**3)
dimsys_length_weight_time.set_quantity_scale_factor(liter, meter**3/1000)
# Newton constant
# REF: NIST SP 959 (June 2019)
dimsys_length_weight_time.set_quantity_dimension(gravitational_constant, length ** 3 * mass ** -1 * time ** -2)
dimsys_length_weight_time.set_quantity_scale_factor(gravitational_constant, 6.67430e-11*m**3/(kg*s**2))
# speed of light
dimsys_length_weight_time.set_quantity_dimension(speed_of_light, velocity)
dimsys_length_weight_time.set_quantity_scale_factor(speed_of_light, 299792458*meter/second)
# Planck constant
# REF: NIST SP 959 (June 2019)
dimsys_length_weight_time.set_quantity_dimension(planck, action)
dimsys_length_weight_time.set_quantity_scale_factor(planck, 6.62607015e-34*joule*second)
# Reduced Planck constant
# REF: NIST SP 959 (June 2019)
dimsys_length_weight_time.set_quantity_dimension(hbar, action)
dimsys_length_weight_time.set_quantity_scale_factor(hbar, planck / (2 * pi))
__all__ = [
'mmHg', 'atmosphere', 'newton', 'meter', 'vacuum_permittivity', 'pascal',
'magnetic_constant', 'angular_mil', 'julian_year', 'weber', 'exbibyte',
'liter', 'molar_gas_constant', 'faraday_constant', 'avogadro_constant',
'planck_momentum', 'planck_density', 'gee', 'mol', 'bit', 'gray', 'kibi',
'bar', 'curie', 'prefix_unit', 'PREFIXES', 'planck_time', 'gram',
'candela', 'force', 'planck_intensity', 'energy', 'becquerel',
'planck_acceleration', 'speed_of_light', 'dioptre', 'second', 'frequency',
'Hz', 'power', 'lux', 'planck_current', 'momentum', 'tebibyte',
'planck_power', 'degree', 'mebi', 'K', 'planck_volume',
'quart', 'pressure', 'W', 'joule', 'boltzmann_constant', 'c', 'g',
'planck_force', 'exbi', 's', 'watt', 'action', 'hbar', 'gibibyte',
'DimensionSystem', 'cd', 'volt', 'planck_charge', 'angstrom',
'dimsys_length_weight_time', 'pebi', 'vacuum_impedance', 'planck',
'farad', 'gravitational_constant', 'u0', 'hertz', 'tesla', 'steradian',
'josephson_constant', 'planck_area', 'stefan_boltzmann_constant',
'astronomical_unit', 'J', 'N', 'planck_voltage', 'planck_energy',
'atomic_mass_constant', 'rutherford', 'elementary_charge', 'Pa',
'planck_mass', 'henry', 'planck_angular_frequency', 'ohm', 'pound',
'planck_pressure', 'G', 'avogadro_number', 'psi', 'von_klitzing_constant',
'planck_length', 'radian', 'mole', 'acceleration',
'planck_energy_density', 'mebibyte', 'length',
'acceleration_due_to_gravity', 'planck_temperature', 'tebi', 'inch',
'electronvolt', 'coulomb_constant', 'kelvin', 'kPa', 'boltzmann',
'milli_mass_unit', 'gibi', 'planck_impedance', 'electric_constant', 'kg',
'coulomb', 'siemens', 'byte', 'atomic_mass_unit', 'm', 'kibibyte',
'kilogram', 'lightyear', 'mass', 'time', 'pebibyte', 'velocity',
'ampere', 'katal',
]
PK ]ZZZM �c
" sympy/physics/units/systems/mks.py"""
MKS unit system.
MKS stands for "meter, kilogram, second".
"""
from sympy.physics.units import UnitSystem
from sympy.physics.units.definitions import gravitational_constant, hertz, joule, newton, pascal, watt, speed_of_light, gram, kilogram, meter, second
from sympy.physics.units.definitions.dimension_definitions import (
acceleration, action, energy, force, frequency, momentum,
power, pressure, velocity, length, mass, time)
from sympy.physics.units.prefixes import PREFIXES, prefix_unit
from sympy.physics.units.systems.length_weight_time import dimsys_length_weight_time
dims = (velocity, acceleration, momentum, force, energy, power, pressure,
frequency, action)
units = [meter, gram, second, joule, newton, watt, pascal, hertz]
all_units = []
# Prefixes of units like gram, joule, newton etc get added using `prefix_unit`
# in the for loop, but the actual units have to be added manually.
all_units.extend([gram, joule, newton, watt, pascal, hertz])
for u in units:
all_units.extend(prefix_unit(u, PREFIXES))
all_units.extend([gravitational_constant, speed_of_light])
# unit system
MKS = UnitSystem(base_units=(meter, kilogram, second), units=all_units, name="MKS", dimension_system=dimsys_length_weight_time, derived_units={
power: watt,
time: second,
pressure: pascal,
length: meter,
frequency: hertz,
mass: kilogram,
force: newton,
energy: joule,
velocity: meter/second,
acceleration: meter/(second**2),
})
__all__ = [
'MKS', 'units', 'all_units', 'dims',
]
PK ]ZZZeY߷� � # sympy/physics/units/systems/mksa.py"""
MKS unit system.
MKS stands for "meter, kilogram, second, ampere".
"""
from __future__ import annotations
from sympy.physics.units.definitions import Z0, ampere, coulomb, farad, henry, siemens, tesla, volt, weber, ohm
from sympy.physics.units.definitions.dimension_definitions import (
capacitance, charge, conductance, current, impedance, inductance,
magnetic_density, magnetic_flux, voltage)
from sympy.physics.units.prefixes import PREFIXES, prefix_unit
from sympy.physics.units.systems.mks import MKS, dimsys_length_weight_time
from sympy.physics.units.quantities import Quantity
dims = (voltage, impedance, conductance, current, capacitance, inductance, charge,
magnetic_density, magnetic_flux)
units = [ampere, volt, ohm, siemens, farad, henry, coulomb, tesla, weber]
all_units: list[Quantity] = []
for u in units:
all_units.extend(prefix_unit(u, PREFIXES))
all_units.extend(units)
all_units.append(Z0)
dimsys_MKSA = dimsys_length_weight_time.extend([
# Dimensional dependencies for base dimensions (MKSA not in MKS)
current,
], new_dim_deps={
# Dimensional dependencies for derived dimensions
"voltage": {"mass": 1, "length": 2, "current": -1, "time": -3},
"impedance": {"mass": 1, "length": 2, "current": -2, "time": -3},
"conductance": {"mass": -1, "length": -2, "current": 2, "time": 3},
"capacitance": {"mass": -1, "length": -2, "current": 2, "time": 4},
"inductance": {"mass": 1, "length": 2, "current": -2, "time": -2},
"charge": {"current": 1, "time": 1},
"magnetic_density": {"mass": 1, "current": -1, "time": -2},
"magnetic_flux": {"length": 2, "mass": 1, "current": -1, "time": -2},
})
MKSA = MKS.extend(base=(ampere,), units=all_units, name='MKSA', dimension_system=dimsys_MKSA, derived_units={
magnetic_flux: weber,
impedance: ohm,
current: ampere,
voltage: volt,
inductance: henry,
conductance: siemens,
magnetic_density: tesla,
charge: coulomb,
capacitance: farad,
})
PK ]ZZZ��� � & sympy/physics/units/systems/natural.py"""
Naturalunit system.
The natural system comes from "setting c = 1, hbar = 1". From the computer
point of view it means that we use velocity and action instead of length and
time. Moreover instead of mass we use energy.
"""
from sympy.physics.units import DimensionSystem
from sympy.physics.units.definitions import c, eV, hbar
from sympy.physics.units.definitions.dimension_definitions import (
action, energy, force, frequency, length, mass, momentum,
power, time, velocity)
from sympy.physics.units.prefixes import PREFIXES, prefix_unit
from sympy.physics.units.unitsystem import UnitSystem
# dimension system
_natural_dim = DimensionSystem(
base_dims=(action, energy, velocity),
derived_dims=(length, mass, time, momentum, force, power, frequency)
)
units = prefix_unit(eV, PREFIXES)
# unit system
natural = UnitSystem(base_units=(hbar, eV, c), units=units, name="Natural system")
PK ]ZZZ�{q`�8 �8 ! sympy/physics/units/systems/si.py"""
SI unit system.
Based on MKSA, which stands for "meter, kilogram, second, ampere".
Added kelvin, candela and mole.
"""
from __future__ import annotations
from sympy.physics.units import DimensionSystem, Dimension, dHg0
from sympy.physics.units.quantities import Quantity
from sympy.core.numbers import (Rational, pi)
from sympy.core.singleton import S
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.physics.units.definitions.dimension_definitions import (
acceleration, action, current, impedance, length, mass, time, velocity,
amount_of_substance, temperature, information, frequency, force, pressure,
energy, power, charge, voltage, capacitance, conductance, magnetic_flux,
magnetic_density, inductance, luminous_intensity
)
from sympy.physics.units.definitions import (
kilogram, newton, second, meter, gram, cd, K, joule, watt, pascal, hertz,
coulomb, volt, ohm, siemens, farad, henry, tesla, weber, dioptre, lux,
katal, gray, becquerel, inch, liter, julian_year, gravitational_constant,
speed_of_light, elementary_charge, planck, hbar, electronvolt,
avogadro_number, avogadro_constant, boltzmann_constant, electron_rest_mass,
stefan_boltzmann_constant, Da, atomic_mass_constant, molar_gas_constant,
faraday_constant, josephson_constant, von_klitzing_constant,
acceleration_due_to_gravity, magnetic_constant, vacuum_permittivity,
vacuum_impedance, coulomb_constant, atmosphere, bar, pound, psi, mmHg,
milli_mass_unit, quart, lightyear, astronomical_unit, planck_mass,
planck_time, planck_temperature, planck_length, planck_charge, planck_area,
planck_volume, planck_momentum, planck_energy, planck_force, planck_power,
planck_density, planck_energy_density, planck_intensity,
planck_angular_frequency, planck_pressure, planck_current, planck_voltage,
planck_impedance, planck_acceleration, bit, byte, kibibyte, mebibyte,
gibibyte, tebibyte, pebibyte, exbibyte, curie, rutherford, radian, degree,
steradian, angular_mil, atomic_mass_unit, gee, kPa, ampere, u0, c, kelvin,
mol, mole, candela, m, kg, s, electric_constant, G, boltzmann
)
from sympy.physics.units.prefixes import PREFIXES, prefix_unit
from sympy.physics.units.systems.mksa import MKSA, dimsys_MKSA
derived_dims = (frequency, force, pressure, energy, power, charge, voltage,
capacitance, conductance, magnetic_flux,
magnetic_density, inductance, luminous_intensity)
base_dims = (amount_of_substance, luminous_intensity, temperature)
units = [mol, cd, K, lux, hertz, newton, pascal, joule, watt, coulomb, volt,
farad, ohm, siemens, weber, tesla, henry, candela, lux, becquerel,
gray, katal]
all_units: list[Quantity] = []
for u in units:
all_units.extend(prefix_unit(u, PREFIXES))
all_units.extend(units)
all_units.extend([mol, cd, K, lux])
dimsys_SI = dimsys_MKSA.extend(
[
# Dimensional dependencies for other base dimensions:
temperature,
amount_of_substance,
luminous_intensity,
])
dimsys_default = dimsys_SI.extend(
[information],
)
SI = MKSA.extend(base=(mol, cd, K), units=all_units, name='SI', dimension_system=dimsys_SI, derived_units={
power: watt,
magnetic_flux: weber,
time: second,
impedance: ohm,
pressure: pascal,
current: ampere,
voltage: volt,
length: meter,
frequency: hertz,
inductance: henry,
temperature: kelvin,
amount_of_substance: mole,
luminous_intensity: candela,
conductance: siemens,
mass: kilogram,
magnetic_density: tesla,
charge: coulomb,
force: newton,
capacitance: farad,
energy: joule,
velocity: meter/second,
})
One = S.One
SI.set_quantity_dimension(radian, One)
SI.set_quantity_scale_factor(ampere, One)
SI.set_quantity_scale_factor(kelvin, One)
SI.set_quantity_scale_factor(mole, One)
SI.set_quantity_scale_factor(candela, One)
# MKSA extension to MKS: derived units
SI.set_quantity_scale_factor(coulomb, One)
SI.set_quantity_scale_factor(volt, joule/coulomb)
SI.set_quantity_scale_factor(ohm, volt/ampere)
SI.set_quantity_scale_factor(siemens, ampere/volt)
SI.set_quantity_scale_factor(farad, coulomb/volt)
SI.set_quantity_scale_factor(henry, volt*second/ampere)
SI.set_quantity_scale_factor(tesla, volt*second/meter**2)
SI.set_quantity_scale_factor(weber, joule/ampere)
SI.set_quantity_dimension(lux, luminous_intensity / length ** 2)
SI.set_quantity_scale_factor(lux, steradian*candela/meter**2)
# katal is the SI unit of catalytic activity
SI.set_quantity_dimension(katal, amount_of_substance / time)
SI.set_quantity_scale_factor(katal, mol/second)
# gray is the SI unit of absorbed dose
SI.set_quantity_dimension(gray, energy / mass)
SI.set_quantity_scale_factor(gray, meter**2/second**2)
# becquerel is the SI unit of radioactivity
SI.set_quantity_dimension(becquerel, 1 / time)
SI.set_quantity_scale_factor(becquerel, 1/second)
#### CONSTANTS ####
# elementary charge
# REF: NIST SP 959 (June 2019)
SI.set_quantity_dimension(elementary_charge, charge)
SI.set_quantity_scale_factor(elementary_charge, 1.602176634e-19*coulomb)
# Electronvolt
# REF: NIST SP 959 (June 2019)
SI.set_quantity_dimension(electronvolt, energy)
SI.set_quantity_scale_factor(electronvolt, 1.602176634e-19*joule)
# Avogadro number
# REF: NIST SP 959 (June 2019)
SI.set_quantity_dimension(avogadro_number, One)
SI.set_quantity_scale_factor(avogadro_number, 6.02214076e23)
# Avogadro constant
SI.set_quantity_dimension(avogadro_constant, amount_of_substance ** -1)
SI.set_quantity_scale_factor(avogadro_constant, avogadro_number / mol)
# Boltzmann constant
# REF: NIST SP 959 (June 2019)
SI.set_quantity_dimension(boltzmann_constant, energy / temperature)
SI.set_quantity_scale_factor(boltzmann_constant, 1.380649e-23*joule/kelvin)
# Stefan-Boltzmann constant
# REF: NIST SP 959 (June 2019)
SI.set_quantity_dimension(stefan_boltzmann_constant, energy * time ** -1 * length ** -2 * temperature ** -4)
SI.set_quantity_scale_factor(stefan_boltzmann_constant, pi**2 * boltzmann_constant**4 / (60 * hbar**3 * speed_of_light ** 2))
# Atomic mass
# REF: NIST SP 959 (June 2019)
SI.set_quantity_dimension(atomic_mass_constant, mass)
SI.set_quantity_scale_factor(atomic_mass_constant, 1.66053906660e-24*gram)
# Molar gas constant
# REF: NIST SP 959 (June 2019)
SI.set_quantity_dimension(molar_gas_constant, energy / (temperature * amount_of_substance))
SI.set_quantity_scale_factor(molar_gas_constant, boltzmann_constant * avogadro_constant)
# Faraday constant
SI.set_quantity_dimension(faraday_constant, charge / amount_of_substance)
SI.set_quantity_scale_factor(faraday_constant, elementary_charge * avogadro_constant)
# Josephson constant
SI.set_quantity_dimension(josephson_constant, frequency / voltage)
SI.set_quantity_scale_factor(josephson_constant, 0.5 * planck / elementary_charge)
# Von Klitzing constant
SI.set_quantity_dimension(von_klitzing_constant, voltage / current)
SI.set_quantity_scale_factor(von_klitzing_constant, hbar / elementary_charge ** 2)
# Acceleration due to gravity (on the Earth surface)
SI.set_quantity_dimension(acceleration_due_to_gravity, acceleration)
SI.set_quantity_scale_factor(acceleration_due_to_gravity, 9.80665*meter/second**2)
# magnetic constant:
SI.set_quantity_dimension(magnetic_constant, force / current ** 2)
SI.set_quantity_scale_factor(magnetic_constant, 4*pi/10**7 * newton/ampere**2)
# electric constant:
SI.set_quantity_dimension(vacuum_permittivity, capacitance / length)
SI.set_quantity_scale_factor(vacuum_permittivity, 1/(u0 * c**2))
# vacuum impedance:
SI.set_quantity_dimension(vacuum_impedance, impedance)
SI.set_quantity_scale_factor(vacuum_impedance, u0 * c)
# Electron rest mass
SI.set_quantity_dimension(electron_rest_mass, mass)
SI.set_quantity_scale_factor(electron_rest_mass, 9.1093837015e-31*kilogram)
# Coulomb's constant:
SI.set_quantity_dimension(coulomb_constant, force * length ** 2 / charge ** 2)
SI.set_quantity_scale_factor(coulomb_constant, 1/(4*pi*vacuum_permittivity))
SI.set_quantity_dimension(psi, pressure)
SI.set_quantity_scale_factor(psi, pound * gee / inch ** 2)
SI.set_quantity_dimension(mmHg, pressure)
SI.set_quantity_scale_factor(mmHg, dHg0 * acceleration_due_to_gravity * kilogram / meter**2)
SI.set_quantity_dimension(milli_mass_unit, mass)
SI.set_quantity_scale_factor(milli_mass_unit, atomic_mass_unit/1000)
SI.set_quantity_dimension(quart, length ** 3)
SI.set_quantity_scale_factor(quart, Rational(231, 4) * inch**3)
# Other convenient units and magnitudes
SI.set_quantity_dimension(lightyear, length)
SI.set_quantity_scale_factor(lightyear, speed_of_light*julian_year)
SI.set_quantity_dimension(astronomical_unit, length)
SI.set_quantity_scale_factor(astronomical_unit, 149597870691*meter)
# Fundamental Planck units:
SI.set_quantity_dimension(planck_mass, mass)
SI.set_quantity_scale_factor(planck_mass, sqrt(hbar*speed_of_light/G))
SI.set_quantity_dimension(planck_time, time)
SI.set_quantity_scale_factor(planck_time, sqrt(hbar*G/speed_of_light**5))
SI.set_quantity_dimension(planck_temperature, temperature)
SI.set_quantity_scale_factor(planck_temperature, sqrt(hbar*speed_of_light**5/G/boltzmann**2))
SI.set_quantity_dimension(planck_length, length)
SI.set_quantity_scale_factor(planck_length, sqrt(hbar*G/speed_of_light**3))
SI.set_quantity_dimension(planck_charge, charge)
SI.set_quantity_scale_factor(planck_charge, sqrt(4*pi*electric_constant*hbar*speed_of_light))
# Derived Planck units:
SI.set_quantity_dimension(planck_area, length ** 2)
SI.set_quantity_scale_factor(planck_area, planck_length**2)
SI.set_quantity_dimension(planck_volume, length ** 3)
SI.set_quantity_scale_factor(planck_volume, planck_length**3)
SI.set_quantity_dimension(planck_momentum, mass * velocity)
SI.set_quantity_scale_factor(planck_momentum, planck_mass * speed_of_light)
SI.set_quantity_dimension(planck_energy, energy)
SI.set_quantity_scale_factor(planck_energy, planck_mass * speed_of_light**2)
SI.set_quantity_dimension(planck_force, force)
SI.set_quantity_scale_factor(planck_force, planck_energy / planck_length)
SI.set_quantity_dimension(planck_power, power)
SI.set_quantity_scale_factor(planck_power, planck_energy / planck_time)
SI.set_quantity_dimension(planck_density, mass / length ** 3)
SI.set_quantity_scale_factor(planck_density, planck_mass / planck_length**3)
SI.set_quantity_dimension(planck_energy_density, energy / length ** 3)
SI.set_quantity_scale_factor(planck_energy_density, planck_energy / planck_length**3)
SI.set_quantity_dimension(planck_intensity, mass * time ** (-3))
SI.set_quantity_scale_factor(planck_intensity, planck_energy_density * speed_of_light)
SI.set_quantity_dimension(planck_angular_frequency, 1 / time)
SI.set_quantity_scale_factor(planck_angular_frequency, 1 / planck_time)
SI.set_quantity_dimension(planck_pressure, pressure)
SI.set_quantity_scale_factor(planck_pressure, planck_force / planck_length**2)
SI.set_quantity_dimension(planck_current, current)
SI.set_quantity_scale_factor(planck_current, planck_charge / planck_time)
SI.set_quantity_dimension(planck_voltage, voltage)
SI.set_quantity_scale_factor(planck_voltage, planck_energy / planck_charge)
SI.set_quantity_dimension(planck_impedance, impedance)
SI.set_quantity_scale_factor(planck_impedance, planck_voltage / planck_current)
SI.set_quantity_dimension(planck_acceleration, acceleration)
SI.set_quantity_scale_factor(planck_acceleration, speed_of_light / planck_time)
# Older units for radioactivity
SI.set_quantity_dimension(curie, 1 / time)
SI.set_quantity_scale_factor(curie, 37000000000*becquerel)
SI.set_quantity_dimension(rutherford, 1 / time)
SI.set_quantity_scale_factor(rutherford, 1000000*becquerel)
# check that scale factors are the right SI dimensions:
for _scale_factor, _dimension in zip(
SI._quantity_scale_factors.values(),
SI._quantity_dimension_map.values()
):
dimex = SI.get_dimensional_expr(_scale_factor)
if dimex != 1:
# XXX: equivalent_dims is an instance method taking two arguments in
# addition to self so this can not work:
if not DimensionSystem.equivalent_dims(_dimension, Dimension(dimex)): # type: ignore
raise ValueError("quantity value and dimension mismatch")
del _scale_factor, _dimension
__all__ = [
'mmHg', 'atmosphere', 'inductance', 'newton', 'meter',
'vacuum_permittivity', 'pascal', 'magnetic_constant', 'voltage',
'angular_mil', 'luminous_intensity', 'all_units',
'julian_year', 'weber', 'exbibyte', 'liter',
'molar_gas_constant', 'faraday_constant', 'avogadro_constant',
'lightyear', 'planck_density', 'gee', 'mol', 'bit', 'gray',
'planck_momentum', 'bar', 'magnetic_density', 'prefix_unit', 'PREFIXES',
'planck_time', 'dimex', 'gram', 'candela', 'force', 'planck_intensity',
'energy', 'becquerel', 'planck_acceleration', 'speed_of_light',
'conductance', 'frequency', 'coulomb_constant', 'degree', 'lux', 'planck',
'current', 'planck_current', 'tebibyte', 'planck_power', 'MKSA', 'power',
'K', 'planck_volume', 'quart', 'pressure', 'amount_of_substance',
'joule', 'boltzmann_constant', 'Dimension', 'c', 'planck_force', 'length',
'watt', 'action', 'hbar', 'gibibyte', 'DimensionSystem', 'cd', 'volt',
'planck_charge', 'dioptre', 'vacuum_impedance', 'dimsys_default', 'farad',
'charge', 'gravitational_constant', 'temperature', 'u0', 'hertz',
'capacitance', 'tesla', 'steradian', 'planck_mass', 'josephson_constant',
'planck_area', 'stefan_boltzmann_constant', 'base_dims',
'astronomical_unit', 'radian', 'planck_voltage', 'impedance',
'planck_energy', 'Da', 'atomic_mass_constant', 'rutherford', 'second', 'inch',
'elementary_charge', 'SI', 'electronvolt', 'dimsys_SI', 'henry',
'planck_angular_frequency', 'ohm', 'pound', 'planck_pressure', 'G', 'psi',
'dHg0', 'von_klitzing_constant', 'planck_length', 'avogadro_number',
'mole', 'acceleration', 'information', 'planck_energy_density',
'mebibyte', 's', 'acceleration_due_to_gravity', 'electron_rest_mass',
'planck_temperature', 'units', 'mass', 'dimsys_MKSA', 'kelvin', 'kPa',
'boltzmann', 'milli_mass_unit', 'planck_impedance', 'electric_constant',
'derived_dims', 'kg', 'coulomb', 'siemens', 'byte', 'magnetic_flux',
'atomic_mass_unit', 'm', 'kibibyte', 'kilogram', 'One', 'curie', 'u',
'time', 'pebibyte', 'velocity', 'ampere', 'katal',
]
PK ]ZZZ�W� � sympy/physics/vector/__init__.py__all__ = [
'CoordinateSym', 'ReferenceFrame',
'Dyadic',
'Vector',
'Point',
'cross', 'dot', 'express', 'time_derivative', 'outer',
'kinematic_equations', 'get_motion_params', 'partial_velocity',
'dynamicsymbols',
'vprint', 'vsstrrepr', 'vsprint', 'vpprint', 'vlatex', 'init_vprinting',
'curl', 'divergence', 'gradient', 'is_conservative', 'is_solenoidal',
'scalar_potential', 'scalar_potential_difference',
]
from .frame import CoordinateSym, ReferenceFrame
from .dyadic import Dyadic
from .vector import Vector
from .point import Point
from .functions import (cross, dot, express, time_derivative, outer,
kinematic_equations, get_motion_params, partial_velocity,
dynamicsymbols)
from .printing import (vprint, vsstrrepr, vsprint, vpprint, vlatex,
init_vprinting)
from .fieldfunctions import (curl, divergence, gradient, is_conservative,
is_solenoidal, scalar_potential, scalar_potential_difference)
PK ]ZZZ7���.G .G sympy/physics/vector/dyadic.pyfrom sympy import sympify, Add, ImmutableMatrix as Matrix
from sympy.core.evalf import EvalfMixin
from sympy.printing.defaults import Printable
from mpmath.libmp.libmpf import prec_to_dps
__all__ = ['Dyadic']
class Dyadic(Printable, EvalfMixin):
"""A Dyadic object.
See:
https://en.wikipedia.org/wiki/Dyadic_tensor
Kane, T., Levinson, D. Dynamics Theory and Applications. 1985 McGraw-Hill
A more powerful way to represent a rigid body's inertia. While it is more
complex, by choosing Dyadic components to be in body fixed basis vectors,
the resulting matrix is equivalent to the inertia tensor.
"""
is_number = False
def __init__(self, inlist):
"""
Just like Vector's init, you should not call this unless creating a
zero dyadic.
zd = Dyadic(0)
Stores a Dyadic as a list of lists; the inner list has the measure
number and the two unit vectors; the outerlist holds each unique
unit vector pair.
"""
self.args = []
if inlist == 0:
inlist = []
while len(inlist) != 0:
added = 0
for i, v in enumerate(self.args):
if ((str(inlist[0][1]) == str(self.args[i][1])) and
(str(inlist[0][2]) == str(self.args[i][2]))):
self.args[i] = (self.args[i][0] + inlist[0][0],
inlist[0][1], inlist[0][2])
inlist.remove(inlist[0])
added = 1
break
if added != 1:
self.args.append(inlist[0])
inlist.remove(inlist[0])
i = 0
# This code is to remove empty parts from the list
while i < len(self.args):
if ((self.args[i][0] == 0) | (self.args[i][1] == 0) |
(self.args[i][2] == 0)):
self.args.remove(self.args[i])
i -= 1
i += 1
@property
def func(self):
"""Returns the class Dyadic. """
return Dyadic
def __add__(self, other):
"""The add operator for Dyadic. """
other = _check_dyadic(other)
return Dyadic(self.args + other.args)
__radd__ = __add__
def __mul__(self, other):
"""Multiplies the Dyadic by a sympifyable expression.
Parameters
==========
other : Sympafiable
The scalar to multiply this Dyadic with
Examples
========
>>> from sympy.physics.vector import ReferenceFrame, outer
>>> N = ReferenceFrame('N')
>>> d = outer(N.x, N.x)
>>> 5 * d
5*(N.x|N.x)
"""
newlist = list(self.args)
other = sympify(other)
for i, v in enumerate(newlist):
newlist[i] = (other * newlist[i][0], newlist[i][1],
newlist[i][2])
return Dyadic(newlist)
__rmul__ = __mul__
def dot(self, other):
"""The inner product operator for a Dyadic and a Dyadic or Vector.
Parameters
==========
other : Dyadic or Vector
The other Dyadic or Vector to take the inner product with
Examples
========
>>> from sympy.physics.vector import ReferenceFrame, outer
>>> N = ReferenceFrame('N')
>>> D1 = outer(N.x, N.y)
>>> D2 = outer(N.y, N.y)
>>> D1.dot(D2)
(N.x|N.y)
>>> D1.dot(N.y)
N.x
"""
from sympy.physics.vector.vector import Vector, _check_vector
if isinstance(other, Dyadic):
other = _check_dyadic(other)
ol = Dyadic(0)
for v in self.args:
for v2 in other.args:
ol += v[0] * v2[0] * (v[2].dot(v2[1])) * (v[1].outer(v2[2]))
else:
other = _check_vector(other)
ol = Vector(0)
for v in self.args:
ol += v[0] * v[1] * (v[2].dot(other))
return ol
# NOTE : supports non-advertised Dyadic & Dyadic, Dyadic & Vector notation
__and__ = dot
def __truediv__(self, other):
"""Divides the Dyadic by a sympifyable expression. """
return self.__mul__(1 / other)
def __eq__(self, other):
"""Tests for equality.
Is currently weak; needs stronger comparison testing
"""
if other == 0:
other = Dyadic(0)
other = _check_dyadic(other)
if (self.args == []) and (other.args == []):
return True
elif (self.args == []) or (other.args == []):
return False
return set(self.args) == set(other.args)
def __ne__(self, other):
return not self == other
def __neg__(self):
return self * -1
def _latex(self, printer):
ar = self.args # just to shorten things
if len(ar) == 0:
return str(0)
ol = [] # output list, to be concatenated to a string
for i, v in enumerate(ar):
# if the coef of the dyadic is 1, we skip the 1
if ar[i][0] == 1:
ol.append(' + ' + printer._print(ar[i][1]) + r"\otimes " +
printer._print(ar[i][2]))
# if the coef of the dyadic is -1, we skip the 1
elif ar[i][0] == -1:
ol.append(' - ' +
printer._print(ar[i][1]) +
r"\otimes " +
printer._print(ar[i][2]))
# If the coefficient of the dyadic is not 1 or -1,
# we might wrap it in parentheses, for readability.
elif ar[i][0] != 0:
arg_str = printer._print(ar[i][0])
if isinstance(ar[i][0], Add):
arg_str = '(%s)' % arg_str
if arg_str.startswith('-'):
arg_str = arg_str[1:]
str_start = ' - '
else:
str_start = ' + '
ol.append(str_start + arg_str + printer._print(ar[i][1]) +
r"\otimes " + printer._print(ar[i][2]))
outstr = ''.join(ol)
if outstr.startswith(' + '):
outstr = outstr[3:]
elif outstr.startswith(' '):
outstr = outstr[1:]
return outstr
def _pretty(self, printer):
e = self
class Fake:
baseline = 0
def render(self, *args, **kwargs):
ar = e.args # just to shorten things
mpp = printer
if len(ar) == 0:
return str(0)
bar = "\N{CIRCLED TIMES}" if printer._use_unicode else "|"
ol = [] # output list, to be concatenated to a string
for i, v in enumerate(ar):
# if the coef of the dyadic is 1, we skip the 1
if ar[i][0] == 1:
ol.extend([" + ",
mpp.doprint(ar[i][1]),
bar,
mpp.doprint(ar[i][2])])
# if the coef of the dyadic is -1, we skip the 1
elif ar[i][0] == -1:
ol.extend([" - ",
mpp.doprint(ar[i][1]),
bar,
mpp.doprint(ar[i][2])])
# If the coefficient of the dyadic is not 1 or -1,
# we might wrap it in parentheses, for readability.
elif ar[i][0] != 0:
if isinstance(ar[i][0], Add):
arg_str = mpp._print(
ar[i][0]).parens()[0]
else:
arg_str = mpp.doprint(ar[i][0])
if arg_str.startswith("-"):
arg_str = arg_str[1:]
str_start = " - "
else:
str_start = " + "
ol.extend([str_start, arg_str, " ",
mpp.doprint(ar[i][1]),
bar,
mpp.doprint(ar[i][2])])
outstr = "".join(ol)
if outstr.startswith(" + "):
outstr = outstr[3:]
elif outstr.startswith(" "):
outstr = outstr[1:]
return outstr
return Fake()
def __rsub__(self, other):
return (-1 * self) + other
def _sympystr(self, printer):
"""Printing method. """
ar = self.args # just to shorten things
if len(ar) == 0:
return printer._print(0)
ol = [] # output list, to be concatenated to a string
for i, v in enumerate(ar):
# if the coef of the dyadic is 1, we skip the 1
if ar[i][0] == 1:
ol.append(' + (' + printer._print(ar[i][1]) + '|' +
printer._print(ar[i][2]) + ')')
# if the coef of the dyadic is -1, we skip the 1
elif ar[i][0] == -1:
ol.append(' - (' + printer._print(ar[i][1]) + '|' +
printer._print(ar[i][2]) + ')')
# If the coefficient of the dyadic is not 1 or -1,
# we might wrap it in parentheses, for readability.
elif ar[i][0] != 0:
arg_str = printer._print(ar[i][0])
if isinstance(ar[i][0], Add):
arg_str = "(%s)" % arg_str
if arg_str[0] == '-':
arg_str = arg_str[1:]
str_start = ' - '
else:
str_start = ' + '
ol.append(str_start + arg_str + '*(' +
printer._print(ar[i][1]) +
'|' + printer._print(ar[i][2]) + ')')
outstr = ''.join(ol)
if outstr.startswith(' + '):
outstr = outstr[3:]
elif outstr.startswith(' '):
outstr = outstr[1:]
return outstr
def __sub__(self, other):
"""The subtraction operator. """
return self.__add__(other * -1)
def cross(self, other):
"""Returns the dyadic resulting from the dyadic vector cross product:
Dyadic x Vector.
Parameters
==========
other : Vector
Vector to cross with.
Examples
========
>>> from sympy.physics.vector import ReferenceFrame, outer, cross
>>> N = ReferenceFrame('N')
>>> d = outer(N.x, N.x)
>>> cross(d, N.y)
(N.x|N.z)
"""
from sympy.physics.vector.vector import _check_vector
other = _check_vector(other)
ol = Dyadic(0)
for v in self.args:
ol += v[0] * (v[1].outer((v[2].cross(other))))
return ol
# NOTE : supports non-advertised Dyadic ^ Vector notation
__xor__ = cross
def express(self, frame1, frame2=None):
"""Expresses this Dyadic in alternate frame(s)
The first frame is the list side expression, the second frame is the
right side; if Dyadic is in form A.x|B.y, you can express it in two
different frames. If no second frame is given, the Dyadic is
expressed in only one frame.
Calls the global express function
Parameters
==========
frame1 : ReferenceFrame
The frame to express the left side of the Dyadic in
frame2 : ReferenceFrame
If provided, the frame to express the right side of the Dyadic in
Examples
========
>>> from sympy.physics.vector import ReferenceFrame, outer, dynamicsymbols
>>> from sympy.physics.vector import init_vprinting
>>> init_vprinting(pretty_print=False)
>>> N = ReferenceFrame('N')
>>> q = dynamicsymbols('q')
>>> B = N.orientnew('B', 'Axis', [q, N.z])
>>> d = outer(N.x, N.x)
>>> d.express(B, N)
cos(q)*(B.x|N.x) - sin(q)*(B.y|N.x)
"""
from sympy.physics.vector.functions import express
return express(self, frame1, frame2)
def to_matrix(self, reference_frame, second_reference_frame=None):
"""Returns the matrix form of the dyadic with respect to one or two
reference frames.
Parameters
----------
reference_frame : ReferenceFrame
The reference frame that the rows and columns of the matrix
correspond to. If a second reference frame is provided, this
only corresponds to the rows of the matrix.
second_reference_frame : ReferenceFrame, optional, default=None
The reference frame that the columns of the matrix correspond
to.
Returns
-------
matrix : ImmutableMatrix, shape(3,3)
The matrix that gives the 2D tensor form.
Examples
========
>>> from sympy import symbols, trigsimp
>>> from sympy.physics.vector import ReferenceFrame
>>> from sympy.physics.mechanics import inertia
>>> Ixx, Iyy, Izz, Ixy, Iyz, Ixz = symbols('Ixx, Iyy, Izz, Ixy, Iyz, Ixz')
>>> N = ReferenceFrame('N')
>>> inertia_dyadic = inertia(N, Ixx, Iyy, Izz, Ixy, Iyz, Ixz)
>>> inertia_dyadic.to_matrix(N)
Matrix([
[Ixx, Ixy, Ixz],
[Ixy, Iyy, Iyz],
[Ixz, Iyz, Izz]])
>>> beta = symbols('beta')
>>> A = N.orientnew('A', 'Axis', (beta, N.x))
>>> trigsimp(inertia_dyadic.to_matrix(A))
Matrix([
[ Ixx, Ixy*cos(beta) + Ixz*sin(beta), -Ixy*sin(beta) + Ixz*cos(beta)],
[ Ixy*cos(beta) + Ixz*sin(beta), Iyy*cos(2*beta)/2 + Iyy/2 + Iyz*sin(2*beta) - Izz*cos(2*beta)/2 + Izz/2, -Iyy*sin(2*beta)/2 + Iyz*cos(2*beta) + Izz*sin(2*beta)/2],
[-Ixy*sin(beta) + Ixz*cos(beta), -Iyy*sin(2*beta)/2 + Iyz*cos(2*beta) + Izz*sin(2*beta)/2, -Iyy*cos(2*beta)/2 + Iyy/2 - Iyz*sin(2*beta) + Izz*cos(2*beta)/2 + Izz/2]])
"""
if second_reference_frame is None:
second_reference_frame = reference_frame
return Matrix([i.dot(self).dot(j) for i in reference_frame for j in
second_reference_frame]).reshape(3, 3)
def doit(self, **hints):
"""Calls .doit() on each term in the Dyadic"""
return sum([Dyadic([(v[0].doit(**hints), v[1], v[2])])
for v in self.args], Dyadic(0))
def dt(self, frame):
"""Take the time derivative of this Dyadic in a frame.
This function calls the global time_derivative method
Parameters
==========
frame : ReferenceFrame
The frame to take the time derivative in
Examples
========
>>> from sympy.physics.vector import ReferenceFrame, outer, dynamicsymbols
>>> from sympy.physics.vector import init_vprinting
>>> init_vprinting(pretty_print=False)
>>> N = ReferenceFrame('N')
>>> q = dynamicsymbols('q')
>>> B = N.orientnew('B', 'Axis', [q, N.z])
>>> d = outer(N.x, N.x)
>>> d.dt(B)
- q'*(N.y|N.x) - q'*(N.x|N.y)
"""
from sympy.physics.vector.functions import time_derivative
return time_derivative(self, frame)
def simplify(self):
"""Returns a simplified Dyadic."""
out = Dyadic(0)
for v in self.args:
out += Dyadic([(v[0].simplify(), v[1], v[2])])
return out
def subs(self, *args, **kwargs):
"""Substitution on the Dyadic.
Examples
========
>>> from sympy.physics.vector import ReferenceFrame
>>> from sympy import Symbol
>>> N = ReferenceFrame('N')
>>> s = Symbol('s')
>>> a = s*(N.x|N.x)
>>> a.subs({s: 2})
2*(N.x|N.x)
"""
return sum([Dyadic([(v[0].subs(*args, **kwargs), v[1], v[2])])
for v in self.args], Dyadic(0))
def applyfunc(self, f):
"""Apply a function to each component of a Dyadic."""
if not callable(f):
raise TypeError("`f` must be callable.")
out = Dyadic(0)
for a, b, c in self.args:
out += f(a) * (b.outer(c))
return out
def _eval_evalf(self, prec):
if not self.args:
return self
new_args = []
dps = prec_to_dps(prec)
for inlist in self.args:
new_inlist = list(inlist)
new_inlist[0] = inlist[0].evalf(n=dps)
new_args.append(tuple(new_inlist))
return Dyadic(new_args)
def xreplace(self, rule):
"""
Replace occurrences of objects within the measure numbers of the
Dyadic.
Parameters
==========
rule : dict-like
Expresses a replacement rule.
Returns
=======
Dyadic
Result of the replacement.
Examples
========
>>> from sympy import symbols, pi
>>> from sympy.physics.vector import ReferenceFrame, outer
>>> N = ReferenceFrame('N')
>>> D = outer(N.x, N.x)
>>> x, y, z = symbols('x y z')
>>> ((1 + x*y) * D).xreplace({x: pi})
(pi*y + 1)*(N.x|N.x)
>>> ((1 + x*y) * D).xreplace({x: pi, y: 2})
(1 + 2*pi)*(N.x|N.x)
Replacements occur only if an entire node in the expression tree is
matched:
>>> ((x*y + z) * D).xreplace({x*y: pi})
(z + pi)*(N.x|N.x)
>>> ((x*y*z) * D).xreplace({x*y: pi})
x*y*z*(N.x|N.x)
"""
new_args = []
for inlist in self.args:
new_inlist = list(inlist)
new_inlist[0] = new_inlist[0].xreplace(rule)
new_args.append(tuple(new_inlist))
return Dyadic(new_args)
def _check_dyadic(other):
if not isinstance(other, Dyadic):
raise TypeError('A Dyadic must be supplied')
return other
PK ]ZZZ�He�! �! & sympy/physics/vector/fieldfunctions.pyfrom sympy.core.function import diff
from sympy.core.singleton import S
from sympy.integrals.integrals import integrate
from sympy.physics.vector import Vector, express
from sympy.physics.vector.frame import _check_frame
from sympy.physics.vector.vector import _check_vector
__all__ = ['curl', 'divergence', 'gradient', 'is_conservative',
'is_solenoidal', 'scalar_potential',
'scalar_potential_difference']
def curl(vect, frame):
"""
Returns the curl of a vector field computed wrt the coordinate
symbols of the given frame.
Parameters
==========
vect : Vector
The vector operand
frame : ReferenceFrame
The reference frame to calculate the curl in
Examples
========
>>> from sympy.physics.vector import ReferenceFrame
>>> from sympy.physics.vector import curl
>>> R = ReferenceFrame('R')
>>> v1 = R[1]*R[2]*R.x + R[0]*R[2]*R.y + R[0]*R[1]*R.z
>>> curl(v1, R)
0
>>> v2 = R[0]*R[1]*R[2]*R.x
>>> curl(v2, R)
R_x*R_y*R.y - R_x*R_z*R.z
"""
_check_vector(vect)
if vect == 0:
return Vector(0)
vect = express(vect, frame, variables=True)
# A mechanical approach to avoid looping overheads
vectx = vect.dot(frame.x)
vecty = vect.dot(frame.y)
vectz = vect.dot(frame.z)
outvec = Vector(0)
outvec += (diff(vectz, frame[1]) - diff(vecty, frame[2])) * frame.x
outvec += (diff(vectx, frame[2]) - diff(vectz, frame[0])) * frame.y
outvec += (diff(vecty, frame[0]) - diff(vectx, frame[1])) * frame.z
return outvec
def divergence(vect, frame):
"""
Returns the divergence of a vector field computed wrt the coordinate
symbols of the given frame.
Parameters
==========
vect : Vector
The vector operand
frame : ReferenceFrame
The reference frame to calculate the divergence in
Examples
========
>>> from sympy.physics.vector import ReferenceFrame
>>> from sympy.physics.vector import divergence
>>> R = ReferenceFrame('R')
>>> v1 = R[0]*R[1]*R[2] * (R.x+R.y+R.z)
>>> divergence(v1, R)
R_x*R_y + R_x*R_z + R_y*R_z
>>> v2 = 2*R[1]*R[2]*R.y
>>> divergence(v2, R)
2*R_z
"""
_check_vector(vect)
if vect == 0:
return S.Zero
vect = express(vect, frame, variables=True)
vectx = vect.dot(frame.x)
vecty = vect.dot(frame.y)
vectz = vect.dot(frame.z)
out = S.Zero
out += diff(vectx, frame[0])
out += diff(vecty, frame[1])
out += diff(vectz, frame[2])
return out
def gradient(scalar, frame):
"""
Returns the vector gradient of a scalar field computed wrt the
coordinate symbols of the given frame.
Parameters
==========
scalar : sympifiable
The scalar field to take the gradient of
frame : ReferenceFrame
The frame to calculate the gradient in
Examples
========
>>> from sympy.physics.vector import ReferenceFrame
>>> from sympy.physics.vector import gradient
>>> R = ReferenceFrame('R')
>>> s1 = R[0]*R[1]*R[2]
>>> gradient(s1, R)
R_y*R_z*R.x + R_x*R_z*R.y + R_x*R_y*R.z
>>> s2 = 5*R[0]**2*R[2]
>>> gradient(s2, R)
10*R_x*R_z*R.x + 5*R_x**2*R.z
"""
_check_frame(frame)
outvec = Vector(0)
scalar = express(scalar, frame, variables=True)
for i, x in enumerate(frame):
outvec += diff(scalar, frame[i]) * x
return outvec
def is_conservative(field):
"""
Checks if a field is conservative.
Parameters
==========
field : Vector
The field to check for conservative property
Examples
========
>>> from sympy.physics.vector import ReferenceFrame
>>> from sympy.physics.vector import is_conservative
>>> R = ReferenceFrame('R')
>>> is_conservative(R[1]*R[2]*R.x + R[0]*R[2]*R.y + R[0]*R[1]*R.z)
True
>>> is_conservative(R[2] * R.y)
False
"""
# Field is conservative irrespective of frame
# Take the first frame in the result of the separate method of Vector
if field == Vector(0):
return True
frame = list(field.separate())[0]
return curl(field, frame).simplify() == Vector(0)
def is_solenoidal(field):
"""
Checks if a field is solenoidal.
Parameters
==========
field : Vector
The field to check for solenoidal property
Examples
========
>>> from sympy.physics.vector import ReferenceFrame
>>> from sympy.physics.vector import is_solenoidal
>>> R = ReferenceFrame('R')
>>> is_solenoidal(R[1]*R[2]*R.x + R[0]*R[2]*R.y + R[0]*R[1]*R.z)
True
>>> is_solenoidal(R[1] * R.y)
False
"""
# Field is solenoidal irrespective of frame
# Take the first frame in the result of the separate method in Vector
if field == Vector(0):
return True
frame = list(field.separate())[0]
return divergence(field, frame).simplify() is S.Zero
def scalar_potential(field, frame):
"""
Returns the scalar potential function of a field in a given frame
(without the added integration constant).
Parameters
==========
field : Vector
The vector field whose scalar potential function is to be
calculated
frame : ReferenceFrame
The frame to do the calculation in
Examples
========
>>> from sympy.physics.vector import ReferenceFrame
>>> from sympy.physics.vector import scalar_potential, gradient
>>> R = ReferenceFrame('R')
>>> scalar_potential(R.z, R) == R[2]
True
>>> scalar_field = 2*R[0]**2*R[1]*R[2]
>>> grad_field = gradient(scalar_field, R)
>>> scalar_potential(grad_field, R)
2*R_x**2*R_y*R_z
"""
# Check whether field is conservative
if not is_conservative(field):
raise ValueError("Field is not conservative")
if field == Vector(0):
return S.Zero
# Express the field exntirely in frame
# Substitute coordinate variables also
_check_frame(frame)
field = express(field, frame, variables=True)
# Make a list of dimensions of the frame
dimensions = list(frame)
# Calculate scalar potential function
temp_function = integrate(field.dot(dimensions[0]), frame[0])
for i, dim in enumerate(dimensions[1:]):
partial_diff = diff(temp_function, frame[i + 1])
partial_diff = field.dot(dim) - partial_diff
temp_function += integrate(partial_diff, frame[i + 1])
return temp_function
def scalar_potential_difference(field, frame, point1, point2, origin):
"""
Returns the scalar potential difference between two points in a
certain frame, wrt a given field.
If a scalar field is provided, its values at the two points are
considered. If a conservative vector field is provided, the values
of its scalar potential function at the two points are used.
Returns (potential at position 2) - (potential at position 1)
Parameters
==========
field : Vector/sympyfiable
The field to calculate wrt
frame : ReferenceFrame
The frame to do the calculations in
point1 : Point
The initial Point in given frame
position2 : Point
The second Point in the given frame
origin : Point
The Point to use as reference point for position vector
calculation
Examples
========
>>> from sympy.physics.vector import ReferenceFrame, Point
>>> from sympy.physics.vector import scalar_potential_difference
>>> R = ReferenceFrame('R')
>>> O = Point('O')
>>> P = O.locatenew('P', R[0]*R.x + R[1]*R.y + R[2]*R.z)
>>> vectfield = 4*R[0]*R[1]*R.x + 2*R[0]**2*R.y
>>> scalar_potential_difference(vectfield, R, O, P, O)
2*R_x**2*R_y
>>> Q = O.locatenew('O', 3*R.x + R.y + 2*R.z)
>>> scalar_potential_difference(vectfield, R, P, Q, O)
-2*R_x**2*R_y + 18
"""
_check_frame(frame)
if isinstance(field, Vector):
# Get the scalar potential function
scalar_fn = scalar_potential(field, frame)
else:
# Field is a scalar
scalar_fn = field
# Express positions in required frame
position1 = express(point1.pos_from(origin), frame, variables=True)
position2 = express(point2.pos_from(origin), frame, variables=True)
# Get the two positions as substitution dicts for coordinate variables
subs_dict1 = {}
subs_dict2 = {}
for i, x in enumerate(frame):
subs_dict1[frame[i]] = x.dot(position1)
subs_dict2[frame[i]] = x.dot(position2)
return scalar_fn.subs(subs_dict2) - scalar_fn.subs(subs_dict1)
PK ]ZZZ���k�� �� sympy/physics/vector/frame.pyfrom sympy import (diff, expand, sin, cos, sympify, eye, zeros,
ImmutableMatrix as Matrix, MatrixBase)
from sympy.core.symbol import Symbol
from sympy.simplify.trigsimp import trigsimp
from sympy.physics.vector.vector import Vector, _check_vector
from sympy.utilities.misc import translate
from warnings import warn
__all__ = ['CoordinateSym', 'ReferenceFrame']
class CoordinateSym(Symbol):
"""
A coordinate symbol/base scalar associated wrt a Reference Frame.
Ideally, users should not instantiate this class. Instances of
this class must only be accessed through the corresponding frame
as 'frame[index]'.
CoordinateSyms having the same frame and index parameters are equal
(even though they may be instantiated separately).
Parameters
==========
name : string
The display name of the CoordinateSym
frame : ReferenceFrame
The reference frame this base scalar belongs to
index : 0, 1 or 2
The index of the dimension denoted by this coordinate variable
Examples
========
>>> from sympy.physics.vector import ReferenceFrame, CoordinateSym
>>> A = ReferenceFrame('A')
>>> A[1]
A_y
>>> type(A[0])
<class 'sympy.physics.vector.frame.CoordinateSym'>
>>> a_y = CoordinateSym('a_y', A, 1)
>>> a_y == A[1]
True
"""
def __new__(cls, name, frame, index):
# We can't use the cached Symbol.__new__ because this class depends on
# frame and index, which are not passed to Symbol.__xnew__.
assumptions = {}
super()._sanitize(assumptions, cls)
obj = super().__xnew__(cls, name, **assumptions)
_check_frame(frame)
if index not in range(0, 3):
raise ValueError("Invalid index specified")
obj._id = (frame, index)
return obj
def __getnewargs_ex__(self):
return (self.name, *self._id), {}
@property
def frame(self):
return self._id[0]
def __eq__(self, other):
# Check if the other object is a CoordinateSym of the same frame and
# same index
if isinstance(other, CoordinateSym):
if other._id == self._id:
return True
return False
def __ne__(self, other):
return not self == other
def __hash__(self):
return (self._id[0].__hash__(), self._id[1]).__hash__()
class ReferenceFrame:
"""A reference frame in classical mechanics.
ReferenceFrame is a class used to represent a reference frame in classical
mechanics. It has a standard basis of three unit vectors in the frame's
x, y, and z directions.
It also can have a rotation relative to a parent frame; this rotation is
defined by a direction cosine matrix relating this frame's basis vectors to
the parent frame's basis vectors. It can also have an angular velocity
vector, defined in another frame.
"""
_count = 0
def __init__(self, name, indices=None, latexs=None, variables=None):
"""ReferenceFrame initialization method.
A ReferenceFrame has a set of orthonormal basis vectors, along with
orientations relative to other ReferenceFrames and angular velocities
relative to other ReferenceFrames.
Parameters
==========
indices : tuple of str
Enables the reference frame's basis unit vectors to be accessed by
Python's square bracket indexing notation using the provided three
indice strings and alters the printing of the unit vectors to
reflect this choice.
latexs : tuple of str
Alters the LaTeX printing of the reference frame's basis unit
vectors to the provided three valid LaTeX strings.
Examples
========
>>> from sympy.physics.vector import ReferenceFrame, vlatex
>>> N = ReferenceFrame('N')
>>> N.x
N.x
>>> O = ReferenceFrame('O', indices=('1', '2', '3'))
>>> O.x
O['1']
>>> O['1']
O['1']
>>> P = ReferenceFrame('P', latexs=('A1', 'A2', 'A3'))
>>> vlatex(P.x)
'A1'
``symbols()`` can be used to create multiple Reference Frames in one
step, for example:
>>> from sympy.physics.vector import ReferenceFrame
>>> from sympy import symbols
>>> A, B, C = symbols('A B C', cls=ReferenceFrame)
>>> D, E = symbols('D E', cls=ReferenceFrame, indices=('1', '2', '3'))
>>> A[0]
A_x
>>> D.x
D['1']
>>> E.y
E['2']
>>> type(A) == type(D)
True
Unit dyads for the ReferenceFrame can be accessed through the attributes ``xx``, ``xy``, etc. For example:
>>> from sympy.physics.vector import ReferenceFrame
>>> N = ReferenceFrame('N')
>>> N.yz
(N.y|N.z)
>>> N.zx
(N.z|N.x)
>>> P = ReferenceFrame('P', indices=['1', '2', '3'])
>>> P.xx
(P['1']|P['1'])
>>> P.zy
(P['3']|P['2'])
Unit dyadic is also accessible via the ``u`` attribute:
>>> from sympy.physics.vector import ReferenceFrame
>>> N = ReferenceFrame('N')
>>> N.u
(N.x|N.x) + (N.y|N.y) + (N.z|N.z)
>>> P = ReferenceFrame('P', indices=['1', '2', '3'])
>>> P.u
(P['1']|P['1']) + (P['2']|P['2']) + (P['3']|P['3'])
"""
if not isinstance(name, str):
raise TypeError('Need to supply a valid name')
# The if statements below are for custom printing of basis-vectors for
# each frame.
# First case, when custom indices are supplied
if indices is not None:
if not isinstance(indices, (tuple, list)):
raise TypeError('Supply the indices as a list')
if len(indices) != 3:
raise ValueError('Supply 3 indices')
for i in indices:
if not isinstance(i, str):
raise TypeError('Indices must be strings')
self.str_vecs = [(name + '[\'' + indices[0] + '\']'),
(name + '[\'' + indices[1] + '\']'),
(name + '[\'' + indices[2] + '\']')]
self.pretty_vecs = [(name.lower() + "_" + indices[0]),
(name.lower() + "_" + indices[1]),
(name.lower() + "_" + indices[2])]
self.latex_vecs = [(r"\mathbf{\hat{%s}_{%s}}" % (name.lower(),
indices[0])),
(r"\mathbf{\hat{%s}_{%s}}" % (name.lower(),
indices[1])),
(r"\mathbf{\hat{%s}_{%s}}" % (name.lower(),
indices[2]))]
self.indices = indices
# Second case, when no custom indices are supplied
else:
self.str_vecs = [(name + '.x'), (name + '.y'), (name + '.z')]
self.pretty_vecs = [name.lower() + "_x",
name.lower() + "_y",
name.lower() + "_z"]
self.latex_vecs = [(r"\mathbf{\hat{%s}_x}" % name.lower()),
(r"\mathbf{\hat{%s}_y}" % name.lower()),
(r"\mathbf{\hat{%s}_z}" % name.lower())]
self.indices = ['x', 'y', 'z']
# Different step, for custom latex basis vectors
if latexs is not None:
if not isinstance(latexs, (tuple, list)):
raise TypeError('Supply the indices as a list')
if len(latexs) != 3:
raise ValueError('Supply 3 indices')
for i in latexs:
if not isinstance(i, str):
raise TypeError('Latex entries must be strings')
self.latex_vecs = latexs
self.name = name
self._var_dict = {}
# The _dcm_dict dictionary will only store the dcms of adjacent
# parent-child relationships. The _dcm_cache dictionary will store
# calculated dcm along with all content of _dcm_dict for faster
# retrieval of dcms.
self._dcm_dict = {}
self._dcm_cache = {}
self._ang_vel_dict = {}
self._ang_acc_dict = {}
self._dlist = [self._dcm_dict, self._ang_vel_dict, self._ang_acc_dict]
self._cur = 0
self._x = Vector([(Matrix([1, 0, 0]), self)])
self._y = Vector([(Matrix([0, 1, 0]), self)])
self._z = Vector([(Matrix([0, 0, 1]), self)])
# Associate coordinate symbols wrt this frame
if variables is not None:
if not isinstance(variables, (tuple, list)):
raise TypeError('Supply the variable names as a list/tuple')
if len(variables) != 3:
raise ValueError('Supply 3 variable names')
for i in variables:
if not isinstance(i, str):
raise TypeError('Variable names must be strings')
else:
variables = [name + '_x', name + '_y', name + '_z']
self.varlist = (CoordinateSym(variables[0], self, 0),
CoordinateSym(variables[1], self, 1),
CoordinateSym(variables[2], self, 2))
ReferenceFrame._count += 1
self.index = ReferenceFrame._count
def __getitem__(self, ind):
"""
Returns basis vector for the provided index, if the index is a string.
If the index is a number, returns the coordinate variable correspon-
-ding to that index.
"""
if not isinstance(ind, str):
if ind < 3:
return self.varlist[ind]
else:
raise ValueError("Invalid index provided")
if self.indices[0] == ind:
return self.x
if self.indices[1] == ind:
return self.y
if self.indices[2] == ind:
return self.z
else:
raise ValueError('Not a defined index')
def __iter__(self):
return iter([self.x, self.y, self.z])
def __str__(self):
"""Returns the name of the frame. """
return self.name
__repr__ = __str__
def _dict_list(self, other, num):
"""Returns an inclusive list of reference frames that connect this
reference frame to the provided reference frame.
Parameters
==========
other : ReferenceFrame
The other reference frame to look for a connecting relationship to.
num : integer
``0``, ``1``, and ``2`` will look for orientation, angular
velocity, and angular acceleration relationships between the two
frames, respectively.
Returns
=======
list
Inclusive list of reference frames that connect this reference
frame to the other reference frame.
Examples
========
>>> from sympy.physics.vector import ReferenceFrame
>>> A = ReferenceFrame('A')
>>> B = ReferenceFrame('B')
>>> C = ReferenceFrame('C')
>>> D = ReferenceFrame('D')
>>> B.orient_axis(A, A.x, 1.0)
>>> C.orient_axis(B, B.x, 1.0)
>>> D.orient_axis(C, C.x, 1.0)
>>> D._dict_list(A, 0)
[D, C, B, A]
Raises
======
ValueError
When no path is found between the two reference frames or ``num``
is an incorrect value.
"""
connect_type = {0: 'orientation',
1: 'angular velocity',
2: 'angular acceleration'}
if num not in connect_type.keys():
raise ValueError('Valid values for num are 0, 1, or 2.')
possible_connecting_paths = [[self]]
oldlist = [[]]
while possible_connecting_paths != oldlist:
oldlist = possible_connecting_paths[:] # make a copy
for frame_list in possible_connecting_paths:
frames_adjacent_to_last = frame_list[-1]._dlist[num].keys()
for adjacent_frame in frames_adjacent_to_last:
if adjacent_frame not in frame_list:
connecting_path = frame_list + [adjacent_frame]
if connecting_path not in possible_connecting_paths:
possible_connecting_paths.append(connecting_path)
for connecting_path in oldlist:
if connecting_path[-1] != other:
possible_connecting_paths.remove(connecting_path)
possible_connecting_paths.sort(key=len)
if len(possible_connecting_paths) != 0:
return possible_connecting_paths[0] # selects the shortest path
msg = 'No connecting {} path found between {} and {}.'
raise ValueError(msg.format(connect_type[num], self.name, other.name))
def _w_diff_dcm(self, otherframe):
"""Angular velocity from time differentiating the DCM. """
from sympy.physics.vector.functions import dynamicsymbols
dcm2diff = otherframe.dcm(self)
diffed = dcm2diff.diff(dynamicsymbols._t)
angvelmat = diffed * dcm2diff.T
w1 = trigsimp(expand(angvelmat[7]), recursive=True)
w2 = trigsimp(expand(angvelmat[2]), recursive=True)
w3 = trigsimp(expand(angvelmat[3]), recursive=True)
return Vector([(Matrix([w1, w2, w3]), otherframe)])
def variable_map(self, otherframe):
"""
Returns a dictionary which expresses the coordinate variables
of this frame in terms of the variables of otherframe.
If Vector.simp is True, returns a simplified version of the mapped
values. Else, returns them without simplification.
Simplification of the expressions may take time.
Parameters
==========
otherframe : ReferenceFrame
The other frame to map the variables to
Examples
========
>>> from sympy.physics.vector import ReferenceFrame, dynamicsymbols
>>> A = ReferenceFrame('A')
>>> q = dynamicsymbols('q')
>>> B = A.orientnew('B', 'Axis', [q, A.z])
>>> A.variable_map(B)
{A_x: B_x*cos(q(t)) - B_y*sin(q(t)), A_y: B_x*sin(q(t)) + B_y*cos(q(t)), A_z: B_z}
"""
_check_frame(otherframe)
if (otherframe, Vector.simp) in self._var_dict:
return self._var_dict[(otherframe, Vector.simp)]
else:
vars_matrix = self.dcm(otherframe) * Matrix(otherframe.varlist)
mapping = {}
for i, x in enumerate(self):
if Vector.simp:
mapping[self.varlist[i]] = trigsimp(vars_matrix[i],
method='fu')
else:
mapping[self.varlist[i]] = vars_matrix[i]
self._var_dict[(otherframe, Vector.simp)] = mapping
return mapping
def ang_acc_in(self, otherframe):
"""Returns the angular acceleration Vector of the ReferenceFrame.
Effectively returns the Vector:
``N_alpha_B``
which represent the angular acceleration of B in N, where B is self,
and N is otherframe.
Parameters
==========
otherframe : ReferenceFrame
The ReferenceFrame which the angular acceleration is returned in.
Examples
========
>>> from sympy.physics.vector import ReferenceFrame
>>> N = ReferenceFrame('N')
>>> A = ReferenceFrame('A')
>>> V = 10 * N.x
>>> A.set_ang_acc(N, V)
>>> A.ang_acc_in(N)
10*N.x
"""
_check_frame(otherframe)
if otherframe in self._ang_acc_dict:
return self._ang_acc_dict[otherframe]
else:
return self.ang_vel_in(otherframe).dt(otherframe)
def ang_vel_in(self, otherframe):
"""Returns the angular velocity Vector of the ReferenceFrame.
Effectively returns the Vector:
^N omega ^B
which represent the angular velocity of B in N, where B is self, and
N is otherframe.
Parameters
==========
otherframe : ReferenceFrame
The ReferenceFrame which the angular velocity is returned in.
Examples
========
>>> from sympy.physics.vector import ReferenceFrame
>>> N = ReferenceFrame('N')
>>> A = ReferenceFrame('A')
>>> V = 10 * N.x
>>> A.set_ang_vel(N, V)
>>> A.ang_vel_in(N)
10*N.x
"""
_check_frame(otherframe)
flist = self._dict_list(otherframe, 1)
outvec = Vector(0)
for i in range(len(flist) - 1):
outvec += flist[i]._ang_vel_dict[flist[i + 1]]
return outvec
def dcm(self, otherframe):
r"""Returns the direction cosine matrix of this reference frame
relative to the provided reference frame.
The returned matrix can be used to express the orthogonal unit vectors
of this frame in terms of the orthogonal unit vectors of
``otherframe``.
Parameters
==========
otherframe : ReferenceFrame
The reference frame which the direction cosine matrix of this frame
is formed relative to.
Examples
========
The following example rotates the reference frame A relative to N by a
simple rotation and then calculates the direction cosine matrix of N
relative to A.
>>> from sympy import symbols, sin, cos
>>> from sympy.physics.vector import ReferenceFrame
>>> q1 = symbols('q1')
>>> N = ReferenceFrame('N')
>>> A = ReferenceFrame('A')
>>> A.orient_axis(N, q1, N.x)
>>> N.dcm(A)
Matrix([
[1, 0, 0],
[0, cos(q1), -sin(q1)],
[0, sin(q1), cos(q1)]])
The second row of the above direction cosine matrix represents the
``N.y`` unit vector in N expressed in A. Like so:
>>> Ny = 0*A.x + cos(q1)*A.y - sin(q1)*A.z
Thus, expressing ``N.y`` in A should return the same result:
>>> N.y.express(A)
cos(q1)*A.y - sin(q1)*A.z
Notes
=====
It is important to know what form of the direction cosine matrix is
returned. If ``B.dcm(A)`` is called, it means the "direction cosine
matrix of B rotated relative to A". This is the matrix
:math:`{}^B\mathbf{C}^A` shown in the following relationship:
.. math::
\begin{bmatrix}
\hat{\mathbf{b}}_1 \\
\hat{\mathbf{b}}_2 \\
\hat{\mathbf{b}}_3
\end{bmatrix}
=
{}^B\mathbf{C}^A
\begin{bmatrix}
\hat{\mathbf{a}}_1 \\
\hat{\mathbf{a}}_2 \\
\hat{\mathbf{a}}_3
\end{bmatrix}.
:math:`{}^B\mathbf{C}^A` is the matrix that expresses the B unit
vectors in terms of the A unit vectors.
"""
_check_frame(otherframe)
# Check if the dcm wrt that frame has already been calculated
if otherframe in self._dcm_cache:
return self._dcm_cache[otherframe]
flist = self._dict_list(otherframe, 0)
outdcm = eye(3)
for i in range(len(flist) - 1):
outdcm = outdcm * flist[i]._dcm_dict[flist[i + 1]]
# After calculation, store the dcm in dcm cache for faster future
# retrieval
self._dcm_cache[otherframe] = outdcm
otherframe._dcm_cache[self] = outdcm.T
return outdcm
def _dcm(self, parent, parent_orient):
# If parent.oreint(self) is already defined,then
# update the _dcm_dict of parent while over write
# all content of self._dcm_dict and self._dcm_cache
# with new dcm relation.
# Else update _dcm_cache and _dcm_dict of both
# self and parent.
frames = self._dcm_cache.keys()
dcm_dict_del = []
dcm_cache_del = []
if parent in frames:
for frame in frames:
if frame in self._dcm_dict:
dcm_dict_del += [frame]
dcm_cache_del += [frame]
# Reset the _dcm_cache of this frame, and remove it from the
# _dcm_caches of the frames it is linked to. Also remove it from
# the _dcm_dict of its parent
for frame in dcm_dict_del:
del frame._dcm_dict[self]
for frame in dcm_cache_del:
del frame._dcm_cache[self]
# Reset the _dcm_dict
self._dcm_dict = self._dlist[0] = {}
# Reset the _dcm_cache
self._dcm_cache = {}
else:
# Check for loops and raise warning accordingly.
visited = []
queue = list(frames)
cont = True # Flag to control queue loop.
while queue and cont:
node = queue.pop(0)
if node not in visited:
visited.append(node)
neighbors = node._dcm_dict.keys()
for neighbor in neighbors:
if neighbor == parent:
warn('Loops are defined among the orientation of '
'frames. This is likely not desired and may '
'cause errors in your calculations.')
cont = False
break
queue.append(neighbor)
# Add the dcm relationship to _dcm_dict
self._dcm_dict.update({parent: parent_orient.T})
parent._dcm_dict.update({self: parent_orient})
# Update the dcm cache
self._dcm_cache.update({parent: parent_orient.T})
parent._dcm_cache.update({self: parent_orient})
def orient_axis(self, parent, axis, angle):
"""Sets the orientation of this reference frame with respect to a
parent reference frame by rotating through an angle about an axis fixed
in the parent reference frame.
Parameters
==========
parent : ReferenceFrame
Reference frame that this reference frame will be rotated relative
to.
axis : Vector
Vector fixed in the parent frame about about which this frame is
rotated. It need not be a unit vector and the rotation follows the
right hand rule.
angle : sympifiable
Angle in radians by which it the frame is to be rotated.
Warns
======
UserWarning
If the orientation creates a kinematic loop.
Examples
========
Setup variables for the examples:
>>> from sympy import symbols
>>> from sympy.physics.vector import ReferenceFrame
>>> q1 = symbols('q1')
>>> N = ReferenceFrame('N')
>>> B = ReferenceFrame('B')
>>> B.orient_axis(N, N.x, q1)
The ``orient_axis()`` method generates a direction cosine matrix and
its transpose which defines the orientation of B relative to N and vice
versa. Once orient is called, ``dcm()`` outputs the appropriate
direction cosine matrix:
>>> B.dcm(N)
Matrix([
[1, 0, 0],
[0, cos(q1), sin(q1)],
[0, -sin(q1), cos(q1)]])
>>> N.dcm(B)
Matrix([
[1, 0, 0],
[0, cos(q1), -sin(q1)],
[0, sin(q1), cos(q1)]])
The following two lines show that the sense of the rotation can be
defined by negating the vector direction or the angle. Both lines
produce the same result.
>>> B.orient_axis(N, -N.x, q1)
>>> B.orient_axis(N, N.x, -q1)
"""
from sympy.physics.vector.functions import dynamicsymbols
_check_frame(parent)
if not isinstance(axis, Vector) and isinstance(angle, Vector):
axis, angle = angle, axis
axis = _check_vector(axis)
theta = sympify(angle)
if not axis.dt(parent) == 0:
raise ValueError('Axis cannot be time-varying.')
unit_axis = axis.express(parent).normalize()
unit_col = unit_axis.args[0][0]
parent_orient_axis = (
(eye(3) - unit_col * unit_col.T) * cos(theta) +
Matrix([[0, -unit_col[2], unit_col[1]],
[unit_col[2], 0, -unit_col[0]],
[-unit_col[1], unit_col[0], 0]]) *
sin(theta) + unit_col * unit_col.T)
self._dcm(parent, parent_orient_axis)
thetad = (theta).diff(dynamicsymbols._t)
wvec = thetad*axis.express(parent).normalize()
self._ang_vel_dict.update({parent: wvec})
parent._ang_vel_dict.update({self: -wvec})
self._var_dict = {}
def orient_explicit(self, parent, dcm):
"""Sets the orientation of this reference frame relative to another (parent) reference frame
using a direction cosine matrix that describes the rotation from the parent to the child.
Parameters
==========
parent : ReferenceFrame
Reference frame that this reference frame will be rotated relative
to.
dcm : Matrix, shape(3, 3)
Direction cosine matrix that specifies the relative rotation
between the two reference frames.
Warns
======
UserWarning
If the orientation creates a kinematic loop.
Examples
========
Setup variables for the examples:
>>> from sympy import symbols, Matrix, sin, cos
>>> from sympy.physics.vector import ReferenceFrame
>>> q1 = symbols('q1')
>>> A = ReferenceFrame('A')
>>> B = ReferenceFrame('B')
>>> N = ReferenceFrame('N')
A simple rotation of ``A`` relative to ``N`` about ``N.x`` is defined
by the following direction cosine matrix:
>>> dcm = Matrix([[1, 0, 0],
... [0, cos(q1), -sin(q1)],
... [0, sin(q1), cos(q1)]])
>>> A.orient_explicit(N, dcm)
>>> A.dcm(N)
Matrix([
[1, 0, 0],
[0, cos(q1), sin(q1)],
[0, -sin(q1), cos(q1)]])
This is equivalent to using ``orient_axis()``:
>>> B.orient_axis(N, N.x, q1)
>>> B.dcm(N)
Matrix([
[1, 0, 0],
[0, cos(q1), sin(q1)],
[0, -sin(q1), cos(q1)]])
**Note carefully that** ``N.dcm(B)`` **(the transpose) would be passed
into** ``orient_explicit()`` **for** ``A.dcm(N)`` **to match**
``B.dcm(N)``:
>>> A.orient_explicit(N, N.dcm(B))
>>> A.dcm(N)
Matrix([
[1, 0, 0],
[0, cos(q1), sin(q1)],
[0, -sin(q1), cos(q1)]])
"""
_check_frame(parent)
# amounts must be a Matrix type object
# (e.g. sympy.matrices.dense.MutableDenseMatrix).
if not isinstance(dcm, MatrixBase):
raise TypeError("Amounts must be a SymPy Matrix type object.")
self.orient_dcm(parent, dcm.T)
def orient_dcm(self, parent, dcm):
"""Sets the orientation of this reference frame relative to another (parent) reference frame
using a direction cosine matrix that describes the rotation from the child to the parent.
Parameters
==========
parent : ReferenceFrame
Reference frame that this reference frame will be rotated relative
to.
dcm : Matrix, shape(3, 3)
Direction cosine matrix that specifies the relative rotation
between the two reference frames.
Warns
======
UserWarning
If the orientation creates a kinematic loop.
Examples
========
Setup variables for the examples:
>>> from sympy import symbols, Matrix, sin, cos
>>> from sympy.physics.vector import ReferenceFrame
>>> q1 = symbols('q1')
>>> A = ReferenceFrame('A')
>>> B = ReferenceFrame('B')
>>> N = ReferenceFrame('N')
A simple rotation of ``A`` relative to ``N`` about ``N.x`` is defined
by the following direction cosine matrix:
>>> dcm = Matrix([[1, 0, 0],
... [0, cos(q1), sin(q1)],
... [0, -sin(q1), cos(q1)]])
>>> A.orient_dcm(N, dcm)
>>> A.dcm(N)
Matrix([
[1, 0, 0],
[0, cos(q1), sin(q1)],
[0, -sin(q1), cos(q1)]])
This is equivalent to using ``orient_axis()``:
>>> B.orient_axis(N, N.x, q1)
>>> B.dcm(N)
Matrix([
[1, 0, 0],
[0, cos(q1), sin(q1)],
[0, -sin(q1), cos(q1)]])
"""
_check_frame(parent)
# amounts must be a Matrix type object
# (e.g. sympy.matrices.dense.MutableDenseMatrix).
if not isinstance(dcm, MatrixBase):
raise TypeError("Amounts must be a SymPy Matrix type object.")
self._dcm(parent, dcm.T)
wvec = self._w_diff_dcm(parent)
self._ang_vel_dict.update({parent: wvec})
parent._ang_vel_dict.update({self: -wvec})
self._var_dict = {}
def _rot(self, axis, angle):
"""DCM for simple axis 1,2,or 3 rotations."""
if axis == 1:
return Matrix([[1, 0, 0],
[0, cos(angle), -sin(angle)],
[0, sin(angle), cos(angle)]])
elif axis == 2:
return Matrix([[cos(angle), 0, sin(angle)],
[0, 1, 0],
[-sin(angle), 0, cos(angle)]])
elif axis == 3:
return Matrix([[cos(angle), -sin(angle), 0],
[sin(angle), cos(angle), 0],
[0, 0, 1]])
def _parse_consecutive_rotations(self, angles, rotation_order):
"""Helper for orient_body_fixed and orient_space_fixed.
Parameters
==========
angles : 3-tuple of sympifiable
Three angles in radians used for the successive rotations.
rotation_order : 3 character string or 3 digit integer
Order of the rotations. The order can be specified by the strings
``'XZX'``, ``'131'``, or the integer ``131``. There are 12 unique
valid rotation orders.
Returns
=======
amounts : list
List of sympifiables corresponding to the rotation angles.
rot_order : list
List of integers corresponding to the axis of rotation.
rot_matrices : list
List of DCM around the given axis with corresponding magnitude.
"""
amounts = list(angles)
for i, v in enumerate(amounts):
if not isinstance(v, Vector):
amounts[i] = sympify(v)
approved_orders = ('123', '231', '312', '132', '213', '321', '121',
'131', '212', '232', '313', '323', '')
# make sure XYZ => 123
rot_order = translate(str(rotation_order), 'XYZxyz', '123123')
if rot_order not in approved_orders:
raise TypeError('The rotation order is not a valid order.')
rot_order = [int(r) for r in rot_order]
if not (len(amounts) == 3 & len(rot_order) == 3):
raise TypeError('Body orientation takes 3 values & 3 orders')
rot_matrices = [self._rot(order, amount)
for (order, amount) in zip(rot_order, amounts)]
return amounts, rot_order, rot_matrices
def orient_body_fixed(self, parent, angles, rotation_order):
"""Rotates this reference frame relative to the parent reference frame
by right hand rotating through three successive body fixed simple axis
rotations. Each subsequent axis of rotation is about the "body fixed"
unit vectors of a new intermediate reference frame. This type of
rotation is also referred to rotating through the `Euler and Tait-Bryan
Angles`_.
.. _Euler and Tait-Bryan Angles: https://en.wikipedia.org/wiki/Euler_angles
The computed angular velocity in this method is by default expressed in
the child's frame, so it is most preferable to use ``u1 * child.x + u2 *
child.y + u3 * child.z`` as generalized speeds.
Parameters
==========
parent : ReferenceFrame
Reference frame that this reference frame will be rotated relative
to.
angles : 3-tuple of sympifiable
Three angles in radians used for the successive rotations.
rotation_order : 3 character string or 3 digit integer
Order of the rotations about each intermediate reference frames'
unit vectors. The Euler rotation about the X, Z', X'' axes can be
specified by the strings ``'XZX'``, ``'131'``, or the integer
``131``. There are 12 unique valid rotation orders (6 Euler and 6
Tait-Bryan): zxz, xyx, yzy, zyz, xzx, yxy, xyz, yzx, zxy, xzy, zyx,
and yxz.
Warns
======
UserWarning
If the orientation creates a kinematic loop.
Examples
========
Setup variables for the examples:
>>> from sympy import symbols
>>> from sympy.physics.vector import ReferenceFrame
>>> q1, q2, q3 = symbols('q1, q2, q3')
>>> N = ReferenceFrame('N')
>>> B = ReferenceFrame('B')
>>> B1 = ReferenceFrame('B1')
>>> B2 = ReferenceFrame('B2')
>>> B3 = ReferenceFrame('B3')
For example, a classic Euler Angle rotation can be done by:
>>> B.orient_body_fixed(N, (q1, q2, q3), 'XYX')
>>> B.dcm(N)
Matrix([
[ cos(q2), sin(q1)*sin(q2), -sin(q2)*cos(q1)],
[sin(q2)*sin(q3), -sin(q1)*sin(q3)*cos(q2) + cos(q1)*cos(q3), sin(q1)*cos(q3) + sin(q3)*cos(q1)*cos(q2)],
[sin(q2)*cos(q3), -sin(q1)*cos(q2)*cos(q3) - sin(q3)*cos(q1), -sin(q1)*sin(q3) + cos(q1)*cos(q2)*cos(q3)]])
This rotates reference frame B relative to reference frame N through
``q1`` about ``N.x``, then rotates B again through ``q2`` about
``B.y``, and finally through ``q3`` about ``B.x``. It is equivalent to
three successive ``orient_axis()`` calls:
>>> B1.orient_axis(N, N.x, q1)
>>> B2.orient_axis(B1, B1.y, q2)
>>> B3.orient_axis(B2, B2.x, q3)
>>> B3.dcm(N)
Matrix([
[ cos(q2), sin(q1)*sin(q2), -sin(q2)*cos(q1)],
[sin(q2)*sin(q3), -sin(q1)*sin(q3)*cos(q2) + cos(q1)*cos(q3), sin(q1)*cos(q3) + sin(q3)*cos(q1)*cos(q2)],
[sin(q2)*cos(q3), -sin(q1)*cos(q2)*cos(q3) - sin(q3)*cos(q1), -sin(q1)*sin(q3) + cos(q1)*cos(q2)*cos(q3)]])
Acceptable rotation orders are of length 3, expressed in as a string
``'XYZ'`` or ``'123'`` or integer ``123``. Rotations about an axis
twice in a row are prohibited.
>>> B.orient_body_fixed(N, (q1, q2, 0), 'ZXZ')
>>> B.orient_body_fixed(N, (q1, q2, 0), '121')
>>> B.orient_body_fixed(N, (q1, q2, q3), 123)
"""
from sympy.physics.vector.functions import dynamicsymbols
_check_frame(parent)
amounts, rot_order, rot_matrices = self._parse_consecutive_rotations(
angles, rotation_order)
self._dcm(parent, rot_matrices[0] * rot_matrices[1] * rot_matrices[2])
rot_vecs = [zeros(3, 1) for _ in range(3)]
for i, order in enumerate(rot_order):
rot_vecs[i][order - 1] = amounts[i].diff(dynamicsymbols._t)
u1, u2, u3 = rot_vecs[2] + rot_matrices[2].T * (
rot_vecs[1] + rot_matrices[1].T * rot_vecs[0])
wvec = u1 * self.x + u2 * self.y + u3 * self.z # There is a double -
self._ang_vel_dict.update({parent: wvec})
parent._ang_vel_dict.update({self: -wvec})
self._var_dict = {}
def orient_space_fixed(self, parent, angles, rotation_order):
"""Rotates this reference frame relative to the parent reference frame
by right hand rotating through three successive space fixed simple axis
rotations. Each subsequent axis of rotation is about the "space fixed"
unit vectors of the parent reference frame.
The computed angular velocity in this method is by default expressed in
the child's frame, so it is most preferable to use ``u1 * child.x + u2 *
child.y + u3 * child.z`` as generalized speeds.
Parameters
==========
parent : ReferenceFrame
Reference frame that this reference frame will be rotated relative
to.
angles : 3-tuple of sympifiable
Three angles in radians used for the successive rotations.
rotation_order : 3 character string or 3 digit integer
Order of the rotations about the parent reference frame's unit
vectors. The order can be specified by the strings ``'XZX'``,
``'131'``, or the integer ``131``. There are 12 unique valid
rotation orders.
Warns
======
UserWarning
If the orientation creates a kinematic loop.
Examples
========
Setup variables for the examples:
>>> from sympy import symbols
>>> from sympy.physics.vector import ReferenceFrame
>>> q1, q2, q3 = symbols('q1, q2, q3')
>>> N = ReferenceFrame('N')
>>> B = ReferenceFrame('B')
>>> B1 = ReferenceFrame('B1')
>>> B2 = ReferenceFrame('B2')
>>> B3 = ReferenceFrame('B3')
>>> B.orient_space_fixed(N, (q1, q2, q3), '312')
>>> B.dcm(N)
Matrix([
[ sin(q1)*sin(q2)*sin(q3) + cos(q1)*cos(q3), sin(q1)*cos(q2), sin(q1)*sin(q2)*cos(q3) - sin(q3)*cos(q1)],
[-sin(q1)*cos(q3) + sin(q2)*sin(q3)*cos(q1), cos(q1)*cos(q2), sin(q1)*sin(q3) + sin(q2)*cos(q1)*cos(q3)],
[ sin(q3)*cos(q2), -sin(q2), cos(q2)*cos(q3)]])
is equivalent to:
>>> B1.orient_axis(N, N.z, q1)
>>> B2.orient_axis(B1, N.x, q2)
>>> B3.orient_axis(B2, N.y, q3)
>>> B3.dcm(N).simplify()
Matrix([
[ sin(q1)*sin(q2)*sin(q3) + cos(q1)*cos(q3), sin(q1)*cos(q2), sin(q1)*sin(q2)*cos(q3) - sin(q3)*cos(q1)],
[-sin(q1)*cos(q3) + sin(q2)*sin(q3)*cos(q1), cos(q1)*cos(q2), sin(q1)*sin(q3) + sin(q2)*cos(q1)*cos(q3)],
[ sin(q3)*cos(q2), -sin(q2), cos(q2)*cos(q3)]])
It is worth noting that space-fixed and body-fixed rotations are
related by the order of the rotations, i.e. the reverse order of body
fixed will give space fixed and vice versa.
>>> B.orient_space_fixed(N, (q1, q2, q3), '231')
>>> B.dcm(N)
Matrix([
[cos(q1)*cos(q2), sin(q1)*sin(q3) + sin(q2)*cos(q1)*cos(q3), -sin(q1)*cos(q3) + sin(q2)*sin(q3)*cos(q1)],
[ -sin(q2), cos(q2)*cos(q3), sin(q3)*cos(q2)],
[sin(q1)*cos(q2), sin(q1)*sin(q2)*cos(q3) - sin(q3)*cos(q1), sin(q1)*sin(q2)*sin(q3) + cos(q1)*cos(q3)]])
>>> B.orient_body_fixed(N, (q3, q2, q1), '132')
>>> B.dcm(N)
Matrix([
[cos(q1)*cos(q2), sin(q1)*sin(q3) + sin(q2)*cos(q1)*cos(q3), -sin(q1)*cos(q3) + sin(q2)*sin(q3)*cos(q1)],
[ -sin(q2), cos(q2)*cos(q3), sin(q3)*cos(q2)],
[sin(q1)*cos(q2), sin(q1)*sin(q2)*cos(q3) - sin(q3)*cos(q1), sin(q1)*sin(q2)*sin(q3) + cos(q1)*cos(q3)]])
"""
from sympy.physics.vector.functions import dynamicsymbols
_check_frame(parent)
amounts, rot_order, rot_matrices = self._parse_consecutive_rotations(
angles, rotation_order)
self._dcm(parent, rot_matrices[2] * rot_matrices[1] * rot_matrices[0])
rot_vecs = [zeros(3, 1) for _ in range(3)]
for i, order in enumerate(rot_order):
rot_vecs[i][order - 1] = amounts[i].diff(dynamicsymbols._t)
u1, u2, u3 = rot_vecs[0] + rot_matrices[0].T * (
rot_vecs[1] + rot_matrices[1].T * rot_vecs[2])
wvec = u1 * self.x + u2 * self.y + u3 * self.z # There is a double -
self._ang_vel_dict.update({parent: wvec})
parent._ang_vel_dict.update({self: -wvec})
self._var_dict = {}
def orient_quaternion(self, parent, numbers):
"""Sets the orientation of this reference frame relative to a parent
reference frame via an orientation quaternion. An orientation
quaternion is defined as a finite rotation a unit vector, ``(lambda_x,
lambda_y, lambda_z)``, by an angle ``theta``. The orientation
quaternion is described by four parameters:
- ``q0 = cos(theta/2)``
- ``q1 = lambda_x*sin(theta/2)``
- ``q2 = lambda_y*sin(theta/2)``
- ``q3 = lambda_z*sin(theta/2)``
See `Quaternions and Spatial Rotation
<https://en.wikipedia.org/wiki/Quaternions_and_spatial_rotation>`_ on
Wikipedia for more information.
Parameters
==========
parent : ReferenceFrame
Reference frame that this reference frame will be rotated relative
to.
numbers : 4-tuple of sympifiable
The four quaternion scalar numbers as defined above: ``q0``,
``q1``, ``q2``, ``q3``.
Warns
======
UserWarning
If the orientation creates a kinematic loop.
Examples
========
Setup variables for the examples:
>>> from sympy import symbols
>>> from sympy.physics.vector import ReferenceFrame
>>> q0, q1, q2, q3 = symbols('q0 q1 q2 q3')
>>> N = ReferenceFrame('N')
>>> B = ReferenceFrame('B')
Set the orientation:
>>> B.orient_quaternion(N, (q0, q1, q2, q3))
>>> B.dcm(N)
Matrix([
[q0**2 + q1**2 - q2**2 - q3**2, 2*q0*q3 + 2*q1*q2, -2*q0*q2 + 2*q1*q3],
[ -2*q0*q3 + 2*q1*q2, q0**2 - q1**2 + q2**2 - q3**2, 2*q0*q1 + 2*q2*q3],
[ 2*q0*q2 + 2*q1*q3, -2*q0*q1 + 2*q2*q3, q0**2 - q1**2 - q2**2 + q3**2]])
"""
from sympy.physics.vector.functions import dynamicsymbols
_check_frame(parent)
numbers = list(numbers)
for i, v in enumerate(numbers):
if not isinstance(v, Vector):
numbers[i] = sympify(v)
if not (isinstance(numbers, (list, tuple)) & (len(numbers) == 4)):
raise TypeError('Amounts are a list or tuple of length 4')
q0, q1, q2, q3 = numbers
parent_orient_quaternion = (
Matrix([[q0**2 + q1**2 - q2**2 - q3**2,
2 * (q1 * q2 - q0 * q3),
2 * (q0 * q2 + q1 * q3)],
[2 * (q1 * q2 + q0 * q3),
q0**2 - q1**2 + q2**2 - q3**2,
2 * (q2 * q3 - q0 * q1)],
[2 * (q1 * q3 - q0 * q2),
2 * (q0 * q1 + q2 * q3),
q0**2 - q1**2 - q2**2 + q3**2]]))
self._dcm(parent, parent_orient_quaternion)
t = dynamicsymbols._t
q0, q1, q2, q3 = numbers
q0d = diff(q0, t)
q1d = diff(q1, t)
q2d = diff(q2, t)
q3d = diff(q3, t)
w1 = 2 * (q1d * q0 + q2d * q3 - q3d * q2 - q0d * q1)
w2 = 2 * (q2d * q0 + q3d * q1 - q1d * q3 - q0d * q2)
w3 = 2 * (q3d * q0 + q1d * q2 - q2d * q1 - q0d * q3)
wvec = Vector([(Matrix([w1, w2, w3]), self)])
self._ang_vel_dict.update({parent: wvec})
parent._ang_vel_dict.update({self: -wvec})
self._var_dict = {}
def orient(self, parent, rot_type, amounts, rot_order=''):
"""Sets the orientation of this reference frame relative to another
(parent) reference frame.
.. note:: It is now recommended to use the ``.orient_axis,
.orient_body_fixed, .orient_space_fixed, .orient_quaternion``
methods for the different rotation types.
Parameters
==========
parent : ReferenceFrame
Reference frame that this reference frame will be rotated relative
to.
rot_type : str
The method used to generate the direction cosine matrix. Supported
methods are:
- ``'Axis'``: simple rotations about a single common axis
- ``'DCM'``: for setting the direction cosine matrix directly
- ``'Body'``: three successive rotations about new intermediate
axes, also called "Euler and Tait-Bryan angles"
- ``'Space'``: three successive rotations about the parent
frames' unit vectors
- ``'Quaternion'``: rotations defined by four parameters which
result in a singularity free direction cosine matrix
amounts :
Expressions defining the rotation angles or direction cosine
matrix. These must match the ``rot_type``. See examples below for
details. The input types are:
- ``'Axis'``: 2-tuple (expr/sym/func, Vector)
- ``'DCM'``: Matrix, shape(3,3)
- ``'Body'``: 3-tuple of expressions, symbols, or functions
- ``'Space'``: 3-tuple of expressions, symbols, or functions
- ``'Quaternion'``: 4-tuple of expressions, symbols, or
functions
rot_order : str or int, optional
If applicable, the order of the successive of rotations. The string
``'123'`` and integer ``123`` are equivalent, for example. Required
for ``'Body'`` and ``'Space'``.
Warns
======
UserWarning
If the orientation creates a kinematic loop.
"""
_check_frame(parent)
approved_orders = ('123', '231', '312', '132', '213', '321', '121',
'131', '212', '232', '313', '323', '')
rot_order = translate(str(rot_order), 'XYZxyz', '123123')
rot_type = rot_type.upper()
if rot_order not in approved_orders:
raise TypeError('The supplied order is not an approved type')
if rot_type == 'AXIS':
self.orient_axis(parent, amounts[1], amounts[0])
elif rot_type == 'DCM':
self.orient_explicit(parent, amounts)
elif rot_type == 'BODY':
self.orient_body_fixed(parent, amounts, rot_order)
elif rot_type == 'SPACE':
self.orient_space_fixed(parent, amounts, rot_order)
elif rot_type == 'QUATERNION':
self.orient_quaternion(parent, amounts)
else:
raise NotImplementedError('That is not an implemented rotation')
def orientnew(self, newname, rot_type, amounts, rot_order='',
variables=None, indices=None, latexs=None):
r"""Returns a new reference frame oriented with respect to this
reference frame.
See ``ReferenceFrame.orient()`` for detailed examples of how to orient
reference frames.
Parameters
==========
newname : str
Name for the new reference frame.
rot_type : str
The method used to generate the direction cosine matrix. Supported
methods are:
- ``'Axis'``: simple rotations about a single common axis
- ``'DCM'``: for setting the direction cosine matrix directly
- ``'Body'``: three successive rotations about new intermediate
axes, also called "Euler and Tait-Bryan angles"
- ``'Space'``: three successive rotations about the parent
frames' unit vectors
- ``'Quaternion'``: rotations defined by four parameters which
result in a singularity free direction cosine matrix
amounts :
Expressions defining the rotation angles or direction cosine
matrix. These must match the ``rot_type``. See examples below for
details. The input types are:
- ``'Axis'``: 2-tuple (expr/sym/func, Vector)
- ``'DCM'``: Matrix, shape(3,3)
- ``'Body'``: 3-tuple of expressions, symbols, or functions
- ``'Space'``: 3-tuple of expressions, symbols, or functions
- ``'Quaternion'``: 4-tuple of expressions, symbols, or
functions
rot_order : str or int, optional
If applicable, the order of the successive of rotations. The string
``'123'`` and integer ``123`` are equivalent, for example. Required
for ``'Body'`` and ``'Space'``.
indices : tuple of str
Enables the reference frame's basis unit vectors to be accessed by
Python's square bracket indexing notation using the provided three
indice strings and alters the printing of the unit vectors to
reflect this choice.
latexs : tuple of str
Alters the LaTeX printing of the reference frame's basis unit
vectors to the provided three valid LaTeX strings.
Examples
========
>>> from sympy import symbols
>>> from sympy.physics.vector import ReferenceFrame, vlatex
>>> q0, q1, q2, q3 = symbols('q0 q1 q2 q3')
>>> N = ReferenceFrame('N')
Create a new reference frame A rotated relative to N through a simple
rotation.
>>> A = N.orientnew('A', 'Axis', (q0, N.x))
Create a new reference frame B rotated relative to N through body-fixed
rotations.
>>> B = N.orientnew('B', 'Body', (q1, q2, q3), '123')
Create a new reference frame C rotated relative to N through a simple
rotation with unique indices and LaTeX printing.
>>> C = N.orientnew('C', 'Axis', (q0, N.x), indices=('1', '2', '3'),
... latexs=(r'\hat{\mathbf{c}}_1',r'\hat{\mathbf{c}}_2',
... r'\hat{\mathbf{c}}_3'))
>>> C['1']
C['1']
>>> print(vlatex(C['1']))
\hat{\mathbf{c}}_1
"""
newframe = self.__class__(newname, variables=variables,
indices=indices, latexs=latexs)
approved_orders = ('123', '231', '312', '132', '213', '321', '121',
'131', '212', '232', '313', '323', '')
rot_order = translate(str(rot_order), 'XYZxyz', '123123')
rot_type = rot_type.upper()
if rot_order not in approved_orders:
raise TypeError('The supplied order is not an approved type')
if rot_type == 'AXIS':
newframe.orient_axis(self, amounts[1], amounts[0])
elif rot_type == 'DCM':
newframe.orient_explicit(self, amounts)
elif rot_type == 'BODY':
newframe.orient_body_fixed(self, amounts, rot_order)
elif rot_type == 'SPACE':
newframe.orient_space_fixed(self, amounts, rot_order)
elif rot_type == 'QUATERNION':
newframe.orient_quaternion(self, amounts)
else:
raise NotImplementedError('That is not an implemented rotation')
return newframe
def set_ang_acc(self, otherframe, value):
"""Define the angular acceleration Vector in a ReferenceFrame.
Defines the angular acceleration of this ReferenceFrame, in another.
Angular acceleration can be defined with respect to multiple different
ReferenceFrames. Care must be taken to not create loops which are
inconsistent.
Parameters
==========
otherframe : ReferenceFrame
A ReferenceFrame to define the angular acceleration in
value : Vector
The Vector representing angular acceleration
Examples
========
>>> from sympy.physics.vector import ReferenceFrame
>>> N = ReferenceFrame('N')
>>> A = ReferenceFrame('A')
>>> V = 10 * N.x
>>> A.set_ang_acc(N, V)
>>> A.ang_acc_in(N)
10*N.x
"""
if value == 0:
value = Vector(0)
value = _check_vector(value)
_check_frame(otherframe)
self._ang_acc_dict.update({otherframe: value})
otherframe._ang_acc_dict.update({self: -value})
def set_ang_vel(self, otherframe, value):
"""Define the angular velocity vector in a ReferenceFrame.
Defines the angular velocity of this ReferenceFrame, in another.
Angular velocity can be defined with respect to multiple different
ReferenceFrames. Care must be taken to not create loops which are
inconsistent.
Parameters
==========
otherframe : ReferenceFrame
A ReferenceFrame to define the angular velocity in
value : Vector
The Vector representing angular velocity
Examples
========
>>> from sympy.physics.vector import ReferenceFrame
>>> N = ReferenceFrame('N')
>>> A = ReferenceFrame('A')
>>> V = 10 * N.x
>>> A.set_ang_vel(N, V)
>>> A.ang_vel_in(N)
10*N.x
"""
if value == 0:
value = Vector(0)
value = _check_vector(value)
_check_frame(otherframe)
self._ang_vel_dict.update({otherframe: value})
otherframe._ang_vel_dict.update({self: -value})
@property
def x(self):
"""The basis Vector for the ReferenceFrame, in the x direction. """
return self._x
@property
def y(self):
"""The basis Vector for the ReferenceFrame, in the y direction. """
return self._y
@property
def z(self):
"""The basis Vector for the ReferenceFrame, in the z direction. """
return self._z
@property
def xx(self):
"""Unit dyad of basis Vectors x and x for the ReferenceFrame."""
return Vector.outer(self.x, self.x)
@property
def xy(self):
"""Unit dyad of basis Vectors x and y for the ReferenceFrame."""
return Vector.outer(self.x, self.y)
@property
def xz(self):
"""Unit dyad of basis Vectors x and z for the ReferenceFrame."""
return Vector.outer(self.x, self.z)
@property
def yx(self):
"""Unit dyad of basis Vectors y and x for the ReferenceFrame."""
return Vector.outer(self.y, self.x)
@property
def yy(self):
"""Unit dyad of basis Vectors y and y for the ReferenceFrame."""
return Vector.outer(self.y, self.y)
@property
def yz(self):
"""Unit dyad of basis Vectors y and z for the ReferenceFrame."""
return Vector.outer(self.y, self.z)
@property
def zx(self):
"""Unit dyad of basis Vectors z and x for the ReferenceFrame."""
return Vector.outer(self.z, self.x)
@property
def zy(self):
"""Unit dyad of basis Vectors z and y for the ReferenceFrame."""
return Vector.outer(self.z, self.y)
@property
def zz(self):
"""Unit dyad of basis Vectors z and z for the ReferenceFrame."""
return Vector.outer(self.z, self.z)
@property
def u(self):
"""Unit dyadic for the ReferenceFrame."""
return self.xx + self.yy + self.zz
def partial_velocity(self, frame, *gen_speeds):
"""Returns the partial angular velocities of this frame in the given
frame with respect to one or more provided generalized speeds.
Parameters
==========
frame : ReferenceFrame
The frame with which the angular velocity is defined in.
gen_speeds : functions of time
The generalized speeds.
Returns
=======
partial_velocities : tuple of Vector
The partial angular velocity vectors corresponding to the provided
generalized speeds.
Examples
========
>>> from sympy.physics.vector import ReferenceFrame, dynamicsymbols
>>> N = ReferenceFrame('N')
>>> A = ReferenceFrame('A')
>>> u1, u2 = dynamicsymbols('u1, u2')
>>> A.set_ang_vel(N, u1 * A.x + u2 * N.y)
>>> A.partial_velocity(N, u1)
A.x
>>> A.partial_velocity(N, u1, u2)
(A.x, N.y)
"""
from sympy.physics.vector.functions import partial_velocity
vel = self.ang_vel_in(frame)
partials = partial_velocity([vel], gen_speeds, frame)[0]
if len(partials) == 1:
return partials[0]
else:
return tuple(partials)
def _check_frame(other):
from .vector import VectorTypeError
if not isinstance(other, ReferenceFrame):
raise VectorTypeError(other, ReferenceFrame('A'))
PK ]ZZZ�(��` �` ! sympy/physics/vector/functions.pyfrom functools import reduce
from sympy import (sympify, diff, sin, cos, Matrix, symbols,
Function, S, Symbol, linear_eq_to_matrix)
from sympy.integrals.integrals import integrate
from sympy.simplify.trigsimp import trigsimp
from .vector import Vector, _check_vector
from .frame import CoordinateSym, _check_frame
from .dyadic import Dyadic
from .printing import vprint, vsprint, vpprint, vlatex, init_vprinting
from sympy.utilities.iterables import iterable
from sympy.utilities.misc import translate
__all__ = ['cross', 'dot', 'express', 'time_derivative', 'outer',
'kinematic_equations', 'get_motion_params', 'partial_velocity',
'dynamicsymbols', 'vprint', 'vsprint', 'vpprint', 'vlatex',
'init_vprinting']
def cross(vec1, vec2):
"""Cross product convenience wrapper for Vector.cross(): \n"""
if not isinstance(vec1, (Vector, Dyadic)):
raise TypeError('Cross product is between two vectors')
return vec1 ^ vec2
cross.__doc__ += Vector.cross.__doc__ # type: ignore
def dot(vec1, vec2):
"""Dot product convenience wrapper for Vector.dot(): \n"""
if not isinstance(vec1, (Vector, Dyadic)):
raise TypeError('Dot product is between two vectors')
return vec1 & vec2
dot.__doc__ += Vector.dot.__doc__ # type: ignore
def express(expr, frame, frame2=None, variables=False):
"""
Global function for 'express' functionality.
Re-expresses a Vector, scalar(sympyfiable) or Dyadic in given frame.
Refer to the local methods of Vector and Dyadic for details.
If 'variables' is True, then the coordinate variables (CoordinateSym
instances) of other frames present in the vector/scalar field or
dyadic expression are also substituted in terms of the base scalars of
this frame.
Parameters
==========
expr : Vector/Dyadic/scalar(sympyfiable)
The expression to re-express in ReferenceFrame 'frame'
frame: ReferenceFrame
The reference frame to express expr in
frame2 : ReferenceFrame
The other frame required for re-expression(only for Dyadic expr)
variables : boolean
Specifies whether to substitute the coordinate variables present
in expr, in terms of those of frame
Examples
========
>>> from sympy.physics.vector import ReferenceFrame, outer, dynamicsymbols
>>> from sympy.physics.vector import init_vprinting
>>> init_vprinting(pretty_print=False)
>>> N = ReferenceFrame('N')
>>> q = dynamicsymbols('q')
>>> B = N.orientnew('B', 'Axis', [q, N.z])
>>> d = outer(N.x, N.x)
>>> from sympy.physics.vector import express
>>> express(d, B, N)
cos(q)*(B.x|N.x) - sin(q)*(B.y|N.x)
>>> express(B.x, N)
cos(q)*N.x + sin(q)*N.y
>>> express(N[0], B, variables=True)
B_x*cos(q) - B_y*sin(q)
"""
_check_frame(frame)
if expr == 0:
return expr
if isinstance(expr, Vector):
# Given expr is a Vector
if variables:
# If variables attribute is True, substitute the coordinate
# variables in the Vector
frame_list = [x[-1] for x in expr.args]
subs_dict = {}
for f in frame_list:
subs_dict.update(f.variable_map(frame))
expr = expr.subs(subs_dict)
# Re-express in this frame
outvec = Vector([])
for v in expr.args:
if v[1] != frame:
temp = frame.dcm(v[1]) * v[0]
if Vector.simp:
temp = temp.applyfunc(lambda x:
trigsimp(x, method='fu'))
outvec += Vector([(temp, frame)])
else:
outvec += Vector([v])
return outvec
if isinstance(expr, Dyadic):
if frame2 is None:
frame2 = frame
_check_frame(frame2)
ol = Dyadic(0)
for v in expr.args:
ol += express(v[0], frame, variables=variables) * \
(express(v[1], frame, variables=variables) |
express(v[2], frame2, variables=variables))
return ol
else:
if variables:
# Given expr is a scalar field
frame_set = set()
expr = sympify(expr)
# Substitute all the coordinate variables
for x in expr.free_symbols:
if isinstance(x, CoordinateSym) and x.frame != frame:
frame_set.add(x.frame)
subs_dict = {}
for f in frame_set:
subs_dict.update(f.variable_map(frame))
return expr.subs(subs_dict)
return expr
def time_derivative(expr, frame, order=1):
"""
Calculate the time derivative of a vector/scalar field function
or dyadic expression in given frame.
References
==========
https://en.wikipedia.org/wiki/Rotating_reference_frame#Time_derivatives_in_the_two_frames
Parameters
==========
expr : Vector/Dyadic/sympifyable
The expression whose time derivative is to be calculated
frame : ReferenceFrame
The reference frame to calculate the time derivative in
order : integer
The order of the derivative to be calculated
Examples
========
>>> from sympy.physics.vector import ReferenceFrame, dynamicsymbols
>>> from sympy.physics.vector import init_vprinting
>>> init_vprinting(pretty_print=False)
>>> from sympy import Symbol
>>> q1 = Symbol('q1')
>>> u1 = dynamicsymbols('u1')
>>> N = ReferenceFrame('N')
>>> A = N.orientnew('A', 'Axis', [q1, N.x])
>>> v = u1 * N.x
>>> A.set_ang_vel(N, 10*A.x)
>>> from sympy.physics.vector import time_derivative
>>> time_derivative(v, N)
u1'*N.x
>>> time_derivative(u1*A[0], N)
N_x*u1'
>>> B = N.orientnew('B', 'Axis', [u1, N.z])
>>> from sympy.physics.vector import outer
>>> d = outer(N.x, N.x)
>>> time_derivative(d, B)
- u1'*(N.y|N.x) - u1'*(N.x|N.y)
"""
t = dynamicsymbols._t
_check_frame(frame)
if order == 0:
return expr
if order % 1 != 0 or order < 0:
raise ValueError("Unsupported value of order entered")
if isinstance(expr, Vector):
outlist = []
for v in expr.args:
if v[1] == frame:
outlist += [(express(v[0], frame, variables=True).diff(t),
frame)]
else:
outlist += (time_derivative(Vector([v]), v[1]) +
(v[1].ang_vel_in(frame) ^ Vector([v]))).args
outvec = Vector(outlist)
return time_derivative(outvec, frame, order - 1)
if isinstance(expr, Dyadic):
ol = Dyadic(0)
for v in expr.args:
ol += (v[0].diff(t) * (v[1] | v[2]))
ol += (v[0] * (time_derivative(v[1], frame) | v[2]))
ol += (v[0] * (v[1] | time_derivative(v[2], frame)))
return time_derivative(ol, frame, order - 1)
else:
return diff(express(expr, frame, variables=True), t, order)
def outer(vec1, vec2):
"""Outer product convenience wrapper for Vector.outer():\n"""
if not isinstance(vec1, Vector):
raise TypeError('Outer product is between two Vectors')
return vec1.outer(vec2)
outer.__doc__ += Vector.outer.__doc__ # type: ignore
def kinematic_equations(speeds, coords, rot_type, rot_order=''):
"""Gives equations relating the qdot's to u's for a rotation type.
Supply rotation type and order as in orient. Speeds are assumed to be
body-fixed; if we are defining the orientation of B in A using by rot_type,
the angular velocity of B in A is assumed to be in the form: speed[0]*B.x +
speed[1]*B.y + speed[2]*B.z
Parameters
==========
speeds : list of length 3
The body fixed angular velocity measure numbers.
coords : list of length 3 or 4
The coordinates used to define the orientation of the two frames.
rot_type : str
The type of rotation used to create the equations. Body, Space, or
Quaternion only
rot_order : str or int
If applicable, the order of a series of rotations.
Examples
========
>>> from sympy.physics.vector import dynamicsymbols
>>> from sympy.physics.vector import kinematic_equations, vprint
>>> u1, u2, u3 = dynamicsymbols('u1 u2 u3')
>>> q1, q2, q3 = dynamicsymbols('q1 q2 q3')
>>> vprint(kinematic_equations([u1,u2,u3], [q1,q2,q3], 'body', '313'),
... order=None)
[-(u1*sin(q3) + u2*cos(q3))/sin(q2) + q1', -u1*cos(q3) + u2*sin(q3) + q2', (u1*sin(q3) + u2*cos(q3))*cos(q2)/sin(q2) - u3 + q3']
"""
# Code below is checking and sanitizing input
approved_orders = ('123', '231', '312', '132', '213', '321', '121', '131',
'212', '232', '313', '323', '1', '2', '3', '')
# make sure XYZ => 123 and rot_type is in lower case
rot_order = translate(str(rot_order), 'XYZxyz', '123123')
rot_type = rot_type.lower()
if not isinstance(speeds, (list, tuple)):
raise TypeError('Need to supply speeds in a list')
if len(speeds) != 3:
raise TypeError('Need to supply 3 body-fixed speeds')
if not isinstance(coords, (list, tuple)):
raise TypeError('Need to supply coordinates in a list')
if rot_type in ['body', 'space']:
if rot_order not in approved_orders:
raise ValueError('Not an acceptable rotation order')
if len(coords) != 3:
raise ValueError('Need 3 coordinates for body or space')
# Actual hard-coded kinematic differential equations
w1, w2, w3 = speeds
if w1 == w2 == w3 == 0:
return [S.Zero]*3
q1, q2, q3 = coords
q1d, q2d, q3d = [diff(i, dynamicsymbols._t) for i in coords]
s1, s2, s3 = [sin(q1), sin(q2), sin(q3)]
c1, c2, c3 = [cos(q1), cos(q2), cos(q3)]
if rot_type == 'body':
if rot_order == '123':
return [q1d - (w1 * c3 - w2 * s3) / c2, q2d - w1 * s3 - w2 *
c3, q3d - (-w1 * c3 + w2 * s3) * s2 / c2 - w3]
if rot_order == '231':
return [q1d - (w2 * c3 - w3 * s3) / c2, q2d - w2 * s3 - w3 *
c3, q3d - w1 - (- w2 * c3 + w3 * s3) * s2 / c2]
if rot_order == '312':
return [q1d - (-w1 * s3 + w3 * c3) / c2, q2d - w1 * c3 - w3 *
s3, q3d - (w1 * s3 - w3 * c3) * s2 / c2 - w2]
if rot_order == '132':
return [q1d - (w1 * c3 + w3 * s3) / c2, q2d + w1 * s3 - w3 *
c3, q3d - (w1 * c3 + w3 * s3) * s2 / c2 - w2]
if rot_order == '213':
return [q1d - (w1 * s3 + w2 * c3) / c2, q2d - w1 * c3 + w2 *
s3, q3d - (w1 * s3 + w2 * c3) * s2 / c2 - w3]
if rot_order == '321':
return [q1d - (w2 * s3 + w3 * c3) / c2, q2d - w2 * c3 + w3 *
s3, q3d - w1 - (w2 * s3 + w3 * c3) * s2 / c2]
if rot_order == '121':
return [q1d - (w2 * s3 + w3 * c3) / s2, q2d - w2 * c3 + w3 *
s3, q3d - w1 + (w2 * s3 + w3 * c3) * c2 / s2]
if rot_order == '131':
return [q1d - (-w2 * c3 + w3 * s3) / s2, q2d - w2 * s3 - w3 *
c3, q3d - w1 - (w2 * c3 - w3 * s3) * c2 / s2]
if rot_order == '212':
return [q1d - (w1 * s3 - w3 * c3) / s2, q2d - w1 * c3 - w3 *
s3, q3d - (-w1 * s3 + w3 * c3) * c2 / s2 - w2]
if rot_order == '232':
return [q1d - (w1 * c3 + w3 * s3) / s2, q2d + w1 * s3 - w3 *
c3, q3d + (w1 * c3 + w3 * s3) * c2 / s2 - w2]
if rot_order == '313':
return [q1d - (w1 * s3 + w2 * c3) / s2, q2d - w1 * c3 + w2 *
s3, q3d + (w1 * s3 + w2 * c3) * c2 / s2 - w3]
if rot_order == '323':
return [q1d - (-w1 * c3 + w2 * s3) / s2, q2d - w1 * s3 - w2 *
c3, q3d - (w1 * c3 - w2 * s3) * c2 / s2 - w3]
if rot_type == 'space':
if rot_order == '123':
return [q1d - w1 - (w2 * s1 + w3 * c1) * s2 / c2, q2d - w2 *
c1 + w3 * s1, q3d - (w2 * s1 + w3 * c1) / c2]
if rot_order == '231':
return [q1d - (w1 * c1 + w3 * s1) * s2 / c2 - w2, q2d + w1 *
s1 - w3 * c1, q3d - (w1 * c1 + w3 * s1) / c2]
if rot_order == '312':
return [q1d - (w1 * s1 + w2 * c1) * s2 / c2 - w3, q2d - w1 *
c1 + w2 * s1, q3d - (w1 * s1 + w2 * c1) / c2]
if rot_order == '132':
return [q1d - w1 - (-w2 * c1 + w3 * s1) * s2 / c2, q2d - w2 *
s1 - w3 * c1, q3d - (w2 * c1 - w3 * s1) / c2]
if rot_order == '213':
return [q1d - (w1 * s1 - w3 * c1) * s2 / c2 - w2, q2d - w1 *
c1 - w3 * s1, q3d - (-w1 * s1 + w3 * c1) / c2]
if rot_order == '321':
return [q1d - (-w1 * c1 + w2 * s1) * s2 / c2 - w3, q2d - w1 *
s1 - w2 * c1, q3d - (w1 * c1 - w2 * s1) / c2]
if rot_order == '121':
return [q1d - w1 + (w2 * s1 + w3 * c1) * c2 / s2, q2d - w2 *
c1 + w3 * s1, q3d - (w2 * s1 + w3 * c1) / s2]
if rot_order == '131':
return [q1d - w1 - (w2 * c1 - w3 * s1) * c2 / s2, q2d - w2 *
s1 - w3 * c1, q3d - (-w2 * c1 + w3 * s1) / s2]
if rot_order == '212':
return [q1d - (-w1 * s1 + w3 * c1) * c2 / s2 - w2, q2d - w1 *
c1 - w3 * s1, q3d - (w1 * s1 - w3 * c1) / s2]
if rot_order == '232':
return [q1d + (w1 * c1 + w3 * s1) * c2 / s2 - w2, q2d + w1 *
s1 - w3 * c1, q3d - (w1 * c1 + w3 * s1) / s2]
if rot_order == '313':
return [q1d + (w1 * s1 + w2 * c1) * c2 / s2 - w3, q2d - w1 *
c1 + w2 * s1, q3d - (w1 * s1 + w2 * c1) / s2]
if rot_order == '323':
return [q1d - (w1 * c1 - w2 * s1) * c2 / s2 - w3, q2d - w1 *
s1 - w2 * c1, q3d - (-w1 * c1 + w2 * s1) / s2]
elif rot_type == 'quaternion':
if rot_order != '':
raise ValueError('Cannot have rotation order for quaternion')
if len(coords) != 4:
raise ValueError('Need 4 coordinates for quaternion')
# Actual hard-coded kinematic differential equations
e0, e1, e2, e3 = coords
w = Matrix(speeds + [0])
E = Matrix([[e0, -e3, e2, e1],
[e3, e0, -e1, e2],
[-e2, e1, e0, e3],
[-e1, -e2, -e3, e0]])
edots = Matrix([diff(i, dynamicsymbols._t) for i in [e1, e2, e3, e0]])
return list(edots.T - 0.5 * w.T * E.T)
else:
raise ValueError('Not an approved rotation type for this function')
def get_motion_params(frame, **kwargs):
"""
Returns the three motion parameters - (acceleration, velocity, and
position) as vectorial functions of time in the given frame.
If a higher order differential function is provided, the lower order
functions are used as boundary conditions. For example, given the
acceleration, the velocity and position parameters are taken as
boundary conditions.
The values of time at which the boundary conditions are specified
are taken from timevalue1(for position boundary condition) and
timevalue2(for velocity boundary condition).
If any of the boundary conditions are not provided, they are taken
to be zero by default (zero vectors, in case of vectorial inputs). If
the boundary conditions are also functions of time, they are converted
to constants by substituting the time values in the dynamicsymbols._t
time Symbol.
This function can also be used for calculating rotational motion
parameters. Have a look at the Parameters and Examples for more clarity.
Parameters
==========
frame : ReferenceFrame
The frame to express the motion parameters in
acceleration : Vector
Acceleration of the object/frame as a function of time
velocity : Vector
Velocity as function of time or as boundary condition
of velocity at time = timevalue1
position : Vector
Velocity as function of time or as boundary condition
of velocity at time = timevalue1
timevalue1 : sympyfiable
Value of time for position boundary condition
timevalue2 : sympyfiable
Value of time for velocity boundary condition
Examples
========
>>> from sympy.physics.vector import ReferenceFrame, get_motion_params, dynamicsymbols
>>> from sympy.physics.vector import init_vprinting
>>> init_vprinting(pretty_print=False)
>>> from sympy import symbols
>>> R = ReferenceFrame('R')
>>> v1, v2, v3 = dynamicsymbols('v1 v2 v3')
>>> v = v1*R.x + v2*R.y + v3*R.z
>>> get_motion_params(R, position = v)
(v1''*R.x + v2''*R.y + v3''*R.z, v1'*R.x + v2'*R.y + v3'*R.z, v1*R.x + v2*R.y + v3*R.z)
>>> a, b, c = symbols('a b c')
>>> v = a*R.x + b*R.y + c*R.z
>>> get_motion_params(R, velocity = v)
(0, a*R.x + b*R.y + c*R.z, a*t*R.x + b*t*R.y + c*t*R.z)
>>> parameters = get_motion_params(R, acceleration = v)
>>> parameters[1]
a*t*R.x + b*t*R.y + c*t*R.z
>>> parameters[2]
a*t**2/2*R.x + b*t**2/2*R.y + c*t**2/2*R.z
"""
def _process_vector_differential(vectdiff, condition, variable, ordinate,
frame):
"""
Helper function for get_motion methods. Finds derivative of vectdiff
wrt variable, and its integral using the specified boundary condition
at value of variable = ordinate.
Returns a tuple of - (derivative, function and integral) wrt vectdiff
"""
# Make sure boundary condition is independent of 'variable'
if condition != 0:
condition = express(condition, frame, variables=True)
# Special case of vectdiff == 0
if vectdiff == Vector(0):
return (0, 0, condition)
# Express vectdiff completely in condition's frame to give vectdiff1
vectdiff1 = express(vectdiff, frame)
# Find derivative of vectdiff
vectdiff2 = time_derivative(vectdiff, frame)
# Integrate and use boundary condition
vectdiff0 = Vector(0)
lims = (variable, ordinate, variable)
for dim in frame:
function1 = vectdiff1.dot(dim)
abscissa = dim.dot(condition).subs({variable: ordinate})
# Indefinite integral of 'function1' wrt 'variable', using
# the given initial condition (ordinate, abscissa).
vectdiff0 += (integrate(function1, lims) + abscissa) * dim
# Return tuple
return (vectdiff2, vectdiff, vectdiff0)
_check_frame(frame)
# Decide mode of operation based on user's input
if 'acceleration' in kwargs:
mode = 2
elif 'velocity' in kwargs:
mode = 1
else:
mode = 0
# All the possible parameters in kwargs
# Not all are required for every case
# If not specified, set to default values(may or may not be used in
# calculations)
conditions = ['acceleration', 'velocity', 'position',
'timevalue', 'timevalue1', 'timevalue2']
for i, x in enumerate(conditions):
if x not in kwargs:
if i < 3:
kwargs[x] = Vector(0)
else:
kwargs[x] = S.Zero
elif i < 3:
_check_vector(kwargs[x])
else:
kwargs[x] = sympify(kwargs[x])
if mode == 2:
vel = _process_vector_differential(kwargs['acceleration'],
kwargs['velocity'],
dynamicsymbols._t,
kwargs['timevalue2'], frame)[2]
pos = _process_vector_differential(vel, kwargs['position'],
dynamicsymbols._t,
kwargs['timevalue1'], frame)[2]
return (kwargs['acceleration'], vel, pos)
elif mode == 1:
return _process_vector_differential(kwargs['velocity'],
kwargs['position'],
dynamicsymbols._t,
kwargs['timevalue1'], frame)
else:
vel = time_derivative(kwargs['position'], frame)
acc = time_derivative(vel, frame)
return (acc, vel, kwargs['position'])
def partial_velocity(vel_vecs, gen_speeds, frame):
"""Returns a list of partial velocities with respect to the provided
generalized speeds in the given reference frame for each of the supplied
velocity vectors.
The output is a list of lists. The outer list has a number of elements
equal to the number of supplied velocity vectors. The inner lists are, for
each velocity vector, the partial derivatives of that velocity vector with
respect to the generalized speeds supplied.
Parameters
==========
vel_vecs : iterable
An iterable of velocity vectors (angular or linear).
gen_speeds : iterable
An iterable of generalized speeds.
frame : ReferenceFrame
The reference frame that the partial derivatives are going to be taken
in.
Examples
========
>>> from sympy.physics.vector import Point, ReferenceFrame
>>> from sympy.physics.vector import dynamicsymbols
>>> from sympy.physics.vector import partial_velocity
>>> u = dynamicsymbols('u')
>>> N = ReferenceFrame('N')
>>> P = Point('P')
>>> P.set_vel(N, u * N.x)
>>> vel_vecs = [P.vel(N)]
>>> gen_speeds = [u]
>>> partial_velocity(vel_vecs, gen_speeds, N)
[[N.x]]
"""
if not iterable(vel_vecs):
raise TypeError('Velocity vectors must be contained in an iterable.')
if not iterable(gen_speeds):
raise TypeError('Generalized speeds must be contained in an iterable')
vec_partials = []
gen_speeds = list(gen_speeds)
for vel in vel_vecs:
partials = [Vector(0) for _ in gen_speeds]
for components, ref in vel.args:
mat, _ = linear_eq_to_matrix(components, gen_speeds)
for i in range(len(gen_speeds)):
for dim, direction in enumerate(ref):
if mat[dim, i] != 0:
partials[i] += direction * mat[dim, i]
vec_partials.append(partials)
return vec_partials
def dynamicsymbols(names, level=0, **assumptions):
"""Uses symbols and Function for functions of time.
Creates a SymPy UndefinedFunction, which is then initialized as a function
of a variable, the default being Symbol('t').
Parameters
==========
names : str
Names of the dynamic symbols you want to create; works the same way as
inputs to symbols
level : int
Level of differentiation of the returned function; d/dt once of t,
twice of t, etc.
assumptions :
- real(bool) : This is used to set the dynamicsymbol as real,
by default is False.
- positive(bool) : This is used to set the dynamicsymbol as positive,
by default is False.
- commutative(bool) : This is used to set the commutative property of
a dynamicsymbol, by default is True.
- integer(bool) : This is used to set the dynamicsymbol as integer,
by default is False.
Examples
========
>>> from sympy.physics.vector import dynamicsymbols
>>> from sympy import diff, Symbol
>>> q1 = dynamicsymbols('q1')
>>> q1
q1(t)
>>> q2 = dynamicsymbols('q2', real=True)
>>> q2.is_real
True
>>> q3 = dynamicsymbols('q3', positive=True)
>>> q3.is_positive
True
>>> q4, q5 = dynamicsymbols('q4,q5', commutative=False)
>>> bool(q4*q5 != q5*q4)
True
>>> q6 = dynamicsymbols('q6', integer=True)
>>> q6.is_integer
True
>>> diff(q1, Symbol('t'))
Derivative(q1(t), t)
"""
esses = symbols(names, cls=Function, **assumptions)
t = dynamicsymbols._t
if iterable(esses):
esses = [reduce(diff, [t] * level, e(t)) for e in esses]
return esses
else:
return reduce(diff, [t] * level, esses(t))
dynamicsymbols._t = Symbol('t') # type: ignore
dynamicsymbols._str = '\'' # type: ignore
PK ]ZZZ9 ��UP UP sympy/physics/vector/point.pyfrom .vector import Vector, _check_vector
from .frame import _check_frame
from warnings import warn
from sympy.utilities.misc import filldedent
__all__ = ['Point']
class Point:
"""This object represents a point in a dynamic system.
It stores the: position, velocity, and acceleration of a point.
The position is a vector defined as the vector distance from a parent
point to this point.
Parameters
==========
name : string
The display name of the Point
Examples
========
>>> from sympy.physics.vector import Point, ReferenceFrame, dynamicsymbols
>>> from sympy.physics.vector import init_vprinting
>>> init_vprinting(pretty_print=False)
>>> N = ReferenceFrame('N')
>>> O = Point('O')
>>> P = Point('P')
>>> u1, u2, u3 = dynamicsymbols('u1 u2 u3')
>>> O.set_vel(N, u1 * N.x + u2 * N.y + u3 * N.z)
>>> O.acc(N)
u1'*N.x + u2'*N.y + u3'*N.z
``symbols()`` can be used to create multiple Points in a single step, for
example:
>>> from sympy.physics.vector import Point, ReferenceFrame, dynamicsymbols
>>> from sympy.physics.vector import init_vprinting
>>> init_vprinting(pretty_print=False)
>>> from sympy import symbols
>>> N = ReferenceFrame('N')
>>> u1, u2 = dynamicsymbols('u1 u2')
>>> A, B = symbols('A B', cls=Point)
>>> type(A)
<class 'sympy.physics.vector.point.Point'>
>>> A.set_vel(N, u1 * N.x + u2 * N.y)
>>> B.set_vel(N, u2 * N.x + u1 * N.y)
>>> A.acc(N) - B.acc(N)
(u1' - u2')*N.x + (-u1' + u2')*N.y
"""
def __init__(self, name):
"""Initialization of a Point object. """
self.name = name
self._pos_dict = {}
self._vel_dict = {}
self._acc_dict = {}
self._pdlist = [self._pos_dict, self._vel_dict, self._acc_dict]
def __str__(self):
return self.name
__repr__ = __str__
def _check_point(self, other):
if not isinstance(other, Point):
raise TypeError('A Point must be supplied')
def _pdict_list(self, other, num):
"""Returns a list of points that gives the shortest path with respect
to position, velocity, or acceleration from this point to the provided
point.
Parameters
==========
other : Point
A point that may be related to this point by position, velocity, or
acceleration.
num : integer
0 for searching the position tree, 1 for searching the velocity
tree, and 2 for searching the acceleration tree.
Returns
=======
list of Points
A sequence of points from self to other.
Notes
=====
It is not clear if num = 1 or num = 2 actually works because the keys
to ``_vel_dict`` and ``_acc_dict`` are :class:`ReferenceFrame` objects
which do not have the ``_pdlist`` attribute.
"""
outlist = [[self]]
oldlist = [[]]
while outlist != oldlist:
oldlist = outlist[:]
for v in outlist:
templist = v[-1]._pdlist[num].keys()
for v2 in templist:
if not v.__contains__(v2):
littletemplist = v + [v2]
if not outlist.__contains__(littletemplist):
outlist.append(littletemplist)
for v in oldlist:
if v[-1] != other:
outlist.remove(v)
outlist.sort(key=len)
if len(outlist) != 0:
return outlist[0]
raise ValueError('No Connecting Path found between ' + other.name +
' and ' + self.name)
def a1pt_theory(self, otherpoint, outframe, interframe):
"""Sets the acceleration of this point with the 1-point theory.
The 1-point theory for point acceleration looks like this:
^N a^P = ^B a^P + ^N a^O + ^N alpha^B x r^OP + ^N omega^B x (^N omega^B
x r^OP) + 2 ^N omega^B x ^B v^P
where O is a point fixed in B, P is a point moving in B, and B is
rotating in frame N.
Parameters
==========
otherpoint : Point
The first point of the 1-point theory (O)
outframe : ReferenceFrame
The frame we want this point's acceleration defined in (N)
fixedframe : ReferenceFrame
The intermediate frame in this calculation (B)
Examples
========
>>> from sympy.physics.vector import Point, ReferenceFrame
>>> from sympy.physics.vector import dynamicsymbols
>>> from sympy.physics.vector import init_vprinting
>>> init_vprinting(pretty_print=False)
>>> q = dynamicsymbols('q')
>>> q2 = dynamicsymbols('q2')
>>> qd = dynamicsymbols('q', 1)
>>> q2d = dynamicsymbols('q2', 1)
>>> N = ReferenceFrame('N')
>>> B = ReferenceFrame('B')
>>> B.set_ang_vel(N, 5 * B.y)
>>> O = Point('O')
>>> P = O.locatenew('P', q * B.x + q2 * B.y)
>>> P.set_vel(B, qd * B.x + q2d * B.y)
>>> O.set_vel(N, 0)
>>> P.a1pt_theory(O, N, B)
(-25*q + q'')*B.x + q2''*B.y - 10*q'*B.z
"""
_check_frame(outframe)
_check_frame(interframe)
self._check_point(otherpoint)
dist = self.pos_from(otherpoint)
v = self.vel(interframe)
a1 = otherpoint.acc(outframe)
a2 = self.acc(interframe)
omega = interframe.ang_vel_in(outframe)
alpha = interframe.ang_acc_in(outframe)
self.set_acc(outframe, a2 + 2 * (omega.cross(v)) + a1 +
(alpha.cross(dist)) + (omega.cross(omega.cross(dist))))
return self.acc(outframe)
def a2pt_theory(self, otherpoint, outframe, fixedframe):
"""Sets the acceleration of this point with the 2-point theory.
The 2-point theory for point acceleration looks like this:
^N a^P = ^N a^O + ^N alpha^B x r^OP + ^N omega^B x (^N omega^B x r^OP)
where O and P are both points fixed in frame B, which is rotating in
frame N.
Parameters
==========
otherpoint : Point
The first point of the 2-point theory (O)
outframe : ReferenceFrame
The frame we want this point's acceleration defined in (N)
fixedframe : ReferenceFrame
The frame in which both points are fixed (B)
Examples
========
>>> from sympy.physics.vector import Point, ReferenceFrame, dynamicsymbols
>>> from sympy.physics.vector import init_vprinting
>>> init_vprinting(pretty_print=False)
>>> q = dynamicsymbols('q')
>>> qd = dynamicsymbols('q', 1)
>>> N = ReferenceFrame('N')
>>> B = N.orientnew('B', 'Axis', [q, N.z])
>>> O = Point('O')
>>> P = O.locatenew('P', 10 * B.x)
>>> O.set_vel(N, 5 * N.x)
>>> P.a2pt_theory(O, N, B)
- 10*q'**2*B.x + 10*q''*B.y
"""
_check_frame(outframe)
_check_frame(fixedframe)
self._check_point(otherpoint)
dist = self.pos_from(otherpoint)
a = otherpoint.acc(outframe)
omega = fixedframe.ang_vel_in(outframe)
alpha = fixedframe.ang_acc_in(outframe)
self.set_acc(outframe, a + (alpha.cross(dist)) +
(omega.cross(omega.cross(dist))))
return self.acc(outframe)
def acc(self, frame):
"""The acceleration Vector of this Point in a ReferenceFrame.
Parameters
==========
frame : ReferenceFrame
The frame in which the returned acceleration vector will be defined
in.
Examples
========
>>> from sympy.physics.vector import Point, ReferenceFrame
>>> N = ReferenceFrame('N')
>>> p1 = Point('p1')
>>> p1.set_acc(N, 10 * N.x)
>>> p1.acc(N)
10*N.x
"""
_check_frame(frame)
if not (frame in self._acc_dict):
if self.vel(frame) != 0:
return (self._vel_dict[frame]).dt(frame)
else:
return Vector(0)
return self._acc_dict[frame]
def locatenew(self, name, value):
"""Creates a new point with a position defined from this point.
Parameters
==========
name : str
The name for the new point
value : Vector
The position of the new point relative to this point
Examples
========
>>> from sympy.physics.vector import ReferenceFrame, Point
>>> N = ReferenceFrame('N')
>>> P1 = Point('P1')
>>> P2 = P1.locatenew('P2', 10 * N.x)
"""
if not isinstance(name, str):
raise TypeError('Must supply a valid name')
if value == 0:
value = Vector(0)
value = _check_vector(value)
p = Point(name)
p.set_pos(self, value)
self.set_pos(p, -value)
return p
def pos_from(self, otherpoint):
"""Returns a Vector distance between this Point and the other Point.
Parameters
==========
otherpoint : Point
The otherpoint we are locating this one relative to
Examples
========
>>> from sympy.physics.vector import Point, ReferenceFrame
>>> N = ReferenceFrame('N')
>>> p1 = Point('p1')
>>> p2 = Point('p2')
>>> p1.set_pos(p2, 10 * N.x)
>>> p1.pos_from(p2)
10*N.x
"""
outvec = Vector(0)
plist = self._pdict_list(otherpoint, 0)
for i in range(len(plist) - 1):
outvec += plist[i]._pos_dict[plist[i + 1]]
return outvec
def set_acc(self, frame, value):
"""Used to set the acceleration of this Point in a ReferenceFrame.
Parameters
==========
frame : ReferenceFrame
The frame in which this point's acceleration is defined
value : Vector
The vector value of this point's acceleration in the frame
Examples
========
>>> from sympy.physics.vector import Point, ReferenceFrame
>>> N = ReferenceFrame('N')
>>> p1 = Point('p1')
>>> p1.set_acc(N, 10 * N.x)
>>> p1.acc(N)
10*N.x
"""
if value == 0:
value = Vector(0)
value = _check_vector(value)
_check_frame(frame)
self._acc_dict.update({frame: value})
def set_pos(self, otherpoint, value):
"""Used to set the position of this point w.r.t. another point.
Parameters
==========
otherpoint : Point
The other point which this point's location is defined relative to
value : Vector
The vector which defines the location of this point
Examples
========
>>> from sympy.physics.vector import Point, ReferenceFrame
>>> N = ReferenceFrame('N')
>>> p1 = Point('p1')
>>> p2 = Point('p2')
>>> p1.set_pos(p2, 10 * N.x)
>>> p1.pos_from(p2)
10*N.x
"""
if value == 0:
value = Vector(0)
value = _check_vector(value)
self._check_point(otherpoint)
self._pos_dict.update({otherpoint: value})
otherpoint._pos_dict.update({self: -value})
def set_vel(self, frame, value):
"""Sets the velocity Vector of this Point in a ReferenceFrame.
Parameters
==========
frame : ReferenceFrame
The frame in which this point's velocity is defined
value : Vector
The vector value of this point's velocity in the frame
Examples
========
>>> from sympy.physics.vector import Point, ReferenceFrame
>>> N = ReferenceFrame('N')
>>> p1 = Point('p1')
>>> p1.set_vel(N, 10 * N.x)
>>> p1.vel(N)
10*N.x
"""
if value == 0:
value = Vector(0)
value = _check_vector(value)
_check_frame(frame)
self._vel_dict.update({frame: value})
def v1pt_theory(self, otherpoint, outframe, interframe):
"""Sets the velocity of this point with the 1-point theory.
The 1-point theory for point velocity looks like this:
^N v^P = ^B v^P + ^N v^O + ^N omega^B x r^OP
where O is a point fixed in B, P is a point moving in B, and B is
rotating in frame N.
Parameters
==========
otherpoint : Point
The first point of the 1-point theory (O)
outframe : ReferenceFrame
The frame we want this point's velocity defined in (N)
interframe : ReferenceFrame
The intermediate frame in this calculation (B)
Examples
========
>>> from sympy.physics.vector import Point, ReferenceFrame
>>> from sympy.physics.vector import dynamicsymbols
>>> from sympy.physics.vector import init_vprinting
>>> init_vprinting(pretty_print=False)
>>> q = dynamicsymbols('q')
>>> q2 = dynamicsymbols('q2')
>>> qd = dynamicsymbols('q', 1)
>>> q2d = dynamicsymbols('q2', 1)
>>> N = ReferenceFrame('N')
>>> B = ReferenceFrame('B')
>>> B.set_ang_vel(N, 5 * B.y)
>>> O = Point('O')
>>> P = O.locatenew('P', q * B.x + q2 * B.y)
>>> P.set_vel(B, qd * B.x + q2d * B.y)
>>> O.set_vel(N, 0)
>>> P.v1pt_theory(O, N, B)
q'*B.x + q2'*B.y - 5*q*B.z
"""
_check_frame(outframe)
_check_frame(interframe)
self._check_point(otherpoint)
dist = self.pos_from(otherpoint)
v1 = self.vel(interframe)
v2 = otherpoint.vel(outframe)
omega = interframe.ang_vel_in(outframe)
self.set_vel(outframe, v1 + v2 + (omega.cross(dist)))
return self.vel(outframe)
def v2pt_theory(self, otherpoint, outframe, fixedframe):
"""Sets the velocity of this point with the 2-point theory.
The 2-point theory for point velocity looks like this:
^N v^P = ^N v^O + ^N omega^B x r^OP
where O and P are both points fixed in frame B, which is rotating in
frame N.
Parameters
==========
otherpoint : Point
The first point of the 2-point theory (O)
outframe : ReferenceFrame
The frame we want this point's velocity defined in (N)
fixedframe : ReferenceFrame
The frame in which both points are fixed (B)
Examples
========
>>> from sympy.physics.vector import Point, ReferenceFrame, dynamicsymbols
>>> from sympy.physics.vector import init_vprinting
>>> init_vprinting(pretty_print=False)
>>> q = dynamicsymbols('q')
>>> qd = dynamicsymbols('q', 1)
>>> N = ReferenceFrame('N')
>>> B = N.orientnew('B', 'Axis', [q, N.z])
>>> O = Point('O')
>>> P = O.locatenew('P', 10 * B.x)
>>> O.set_vel(N, 5 * N.x)
>>> P.v2pt_theory(O, N, B)
5*N.x + 10*q'*B.y
"""
_check_frame(outframe)
_check_frame(fixedframe)
self._check_point(otherpoint)
dist = self.pos_from(otherpoint)
v = otherpoint.vel(outframe)
omega = fixedframe.ang_vel_in(outframe)
self.set_vel(outframe, v + (omega.cross(dist)))
return self.vel(outframe)
def vel(self, frame):
"""The velocity Vector of this Point in the ReferenceFrame.
Parameters
==========
frame : ReferenceFrame
The frame in which the returned velocity vector will be defined in
Examples
========
>>> from sympy.physics.vector import Point, ReferenceFrame, dynamicsymbols
>>> N = ReferenceFrame('N')
>>> p1 = Point('p1')
>>> p1.set_vel(N, 10 * N.x)
>>> p1.vel(N)
10*N.x
Velocities will be automatically calculated if possible, otherwise a
``ValueError`` will be returned. If it is possible to calculate
multiple different velocities from the relative points, the points
defined most directly relative to this point will be used. In the case
of inconsistent relative positions of points, incorrect velocities may
be returned. It is up to the user to define prior relative positions
and velocities of points in a self-consistent way.
>>> p = Point('p')
>>> q = dynamicsymbols('q')
>>> p.set_vel(N, 10 * N.x)
>>> p2 = Point('p2')
>>> p2.set_pos(p, q*N.x)
>>> p2.vel(N)
(Derivative(q(t), t) + 10)*N.x
"""
_check_frame(frame)
if not (frame in self._vel_dict):
valid_neighbor_found = False
is_cyclic = False
visited = []
queue = [self]
candidate_neighbor = []
while queue: # BFS to find nearest point
node = queue.pop(0)
if node not in visited:
visited.append(node)
for neighbor, neighbor_pos in node._pos_dict.items():
if neighbor in visited:
continue
try:
# Checks if pos vector is valid
neighbor_pos.express(frame)
except ValueError:
continue
if neighbor in queue:
is_cyclic = True
try:
# Checks if point has its vel defined in req frame
neighbor_velocity = neighbor._vel_dict[frame]
except KeyError:
queue.append(neighbor)
continue
candidate_neighbor.append(neighbor)
if not valid_neighbor_found:
self.set_vel(frame, self.pos_from(neighbor).dt(frame) + neighbor_velocity)
valid_neighbor_found = True
if is_cyclic:
warn(filldedent("""
Kinematic loops are defined among the positions of points. This
is likely not desired and may cause errors in your calculations.
"""))
if len(candidate_neighbor) > 1:
warn(filldedent(f"""
Velocity of {self.name} automatically calculated based on point
{candidate_neighbor[0].name} but it is also possible from
points(s): {str(candidate_neighbor[1:])}. Velocities from these
points are not necessarily the same. This may cause errors in
your calculations."""))
if valid_neighbor_found:
return self._vel_dict[frame]
else:
raise ValueError(filldedent(f"""
Velocity of point {self.name} has not been defined in
ReferenceFrame {frame.name}."""))
return self._vel_dict[frame]
def partial_velocity(self, frame, *gen_speeds):
"""Returns the partial velocities of the linear velocity vector of this
point in the given frame with respect to one or more provided
generalized speeds.
Parameters
==========
frame : ReferenceFrame
The frame with which the velocity is defined in.
gen_speeds : functions of time
The generalized speeds.
Returns
=======
partial_velocities : tuple of Vector
The partial velocity vectors corresponding to the provided
generalized speeds.
Examples
========
>>> from sympy.physics.vector import ReferenceFrame, Point
>>> from sympy.physics.vector import dynamicsymbols
>>> N = ReferenceFrame('N')
>>> A = ReferenceFrame('A')
>>> p = Point('p')
>>> u1, u2 = dynamicsymbols('u1, u2')
>>> p.set_vel(N, u1 * N.x + u2 * A.y)
>>> p.partial_velocity(N, u1)
N.x
>>> p.partial_velocity(N, u1, u2)
(N.x, A.y)
"""
from sympy.physics.vector.functions import partial_velocity
vel = self.vel(frame)
partials = partial_velocity([vel], gen_speeds, frame)[0]
if len(partials) == 1:
return partials[0]
else:
return tuple(partials)
PK ]ZZZ� �. . sympy/physics/vector/printing.pyfrom sympy.core.function import Derivative
from sympy.core.function import UndefinedFunction, AppliedUndef
from sympy.core.symbol import Symbol
from sympy.interactive.printing import init_printing
from sympy.printing.latex import LatexPrinter
from sympy.printing.pretty.pretty import PrettyPrinter
from sympy.printing.pretty.pretty_symbology import center_accent
from sympy.printing.str import StrPrinter
from sympy.printing.precedence import PRECEDENCE
__all__ = ['vprint', 'vsstrrepr', 'vsprint', 'vpprint', 'vlatex',
'init_vprinting']
class VectorStrPrinter(StrPrinter):
"""String Printer for vector expressions. """
def _print_Derivative(self, e):
from sympy.physics.vector.functions import dynamicsymbols
t = dynamicsymbols._t
if (bool(sum(i == t for i in e.variables)) &
isinstance(type(e.args[0]), UndefinedFunction)):
ol = str(e.args[0].func)
for i, v in enumerate(e.variables):
ol += dynamicsymbols._str
return ol
else:
return StrPrinter().doprint(e)
def _print_Function(self, e):
from sympy.physics.vector.functions import dynamicsymbols
t = dynamicsymbols._t
if isinstance(type(e), UndefinedFunction):
return StrPrinter().doprint(e).replace("(%s)" % t, '')
return e.func.__name__ + "(%s)" % self.stringify(e.args, ", ")
class VectorStrReprPrinter(VectorStrPrinter):
"""String repr printer for vector expressions."""
def _print_str(self, s):
return repr(s)
class VectorLatexPrinter(LatexPrinter):
"""Latex Printer for vector expressions. """
def _print_Function(self, expr, exp=None):
from sympy.physics.vector.functions import dynamicsymbols
func = expr.func.__name__
t = dynamicsymbols._t
if (hasattr(self, '_print_' + func) and not
isinstance(type(expr), UndefinedFunction)):
return getattr(self, '_print_' + func)(expr, exp)
elif isinstance(type(expr), UndefinedFunction) and (expr.args == (t,)):
# treat this function like a symbol
expr = Symbol(func)
if exp is not None:
# copied from LatexPrinter._helper_print_standard_power, which
# we can't call because we only have exp as a string.
base = self.parenthesize(expr, PRECEDENCE['Pow'])
base = self.parenthesize_super(base)
return r"%s^{%s}" % (base, exp)
else:
return super()._print(expr)
else:
return super()._print_Function(expr, exp)
def _print_Derivative(self, der_expr):
from sympy.physics.vector.functions import dynamicsymbols
# make sure it is in the right form
der_expr = der_expr.doit()
if not isinstance(der_expr, Derivative):
return r"\left(%s\right)" % self.doprint(der_expr)
# check if expr is a dynamicsymbol
t = dynamicsymbols._t
expr = der_expr.expr
red = expr.atoms(AppliedUndef)
syms = der_expr.variables
test1 = not all(True for i in red if i.free_symbols == {t})
test2 = not all(t == i for i in syms)
if test1 or test2:
return super()._print_Derivative(der_expr)
# done checking
dots = len(syms)
base = self._print_Function(expr)
base_split = base.split('_', 1)
base = base_split[0]
if dots == 1:
base = r"\dot{%s}" % base
elif dots == 2:
base = r"\ddot{%s}" % base
elif dots == 3:
base = r"\dddot{%s}" % base
elif dots == 4:
base = r"\ddddot{%s}" % base
else: # Fallback to standard printing
return super()._print_Derivative(der_expr)
if len(base_split) != 1:
base += '_' + base_split[1]
return base
class VectorPrettyPrinter(PrettyPrinter):
"""Pretty Printer for vectorialexpressions. """
def _print_Derivative(self, deriv):
from sympy.physics.vector.functions import dynamicsymbols
# XXX use U('PARTIAL DIFFERENTIAL') here ?
t = dynamicsymbols._t
dot_i = 0
syms = list(reversed(deriv.variables))
while len(syms) > 0:
if syms[-1] == t:
syms.pop()
dot_i += 1
else:
return super()._print_Derivative(deriv)
if not (isinstance(type(deriv.expr), UndefinedFunction) and
(deriv.expr.args == (t,))):
return super()._print_Derivative(deriv)
else:
pform = self._print_Function(deriv.expr)
# the following condition would happen with some sort of non-standard
# dynamic symbol I guess, so we'll just print the SymPy way
if len(pform.picture) > 1:
return super()._print_Derivative(deriv)
# There are only special symbols up to fourth-order derivatives
if dot_i >= 5:
return super()._print_Derivative(deriv)
# Deal with special symbols
dots = {0: "",
1: "\N{COMBINING DOT ABOVE}",
2: "\N{COMBINING DIAERESIS}",
3: "\N{COMBINING THREE DOTS ABOVE}",
4: "\N{COMBINING FOUR DOTS ABOVE}"}
d = pform.__dict__
# if unicode is false then calculate number of apostrophes needed and
# add to output
if not self._use_unicode:
apostrophes = ""
for i in range(0, dot_i):
apostrophes += "'"
d['picture'][0] += apostrophes + "(t)"
else:
d['picture'] = [center_accent(d['picture'][0], dots[dot_i])]
return pform
def _print_Function(self, e):
from sympy.physics.vector.functions import dynamicsymbols
t = dynamicsymbols._t
# XXX works only for applied functions
func = e.func
args = e.args
func_name = func.__name__
pform = self._print_Symbol(Symbol(func_name))
# If this function is an Undefined function of t, it is probably a
# dynamic symbol, so we'll skip the (t). The rest of the code is
# identical to the normal PrettyPrinter code
if not (isinstance(func, UndefinedFunction) and (args == (t,))):
return super()._print_Function(e)
return pform
def vprint(expr, **settings):
r"""Function for printing of expressions generated in the
sympy.physics vector package.
Extends SymPy's StrPrinter, takes the same setting accepted by SymPy's
:func:`~.sstr`, and is equivalent to ``print(sstr(foo))``.
Parameters
==========
expr : valid SymPy object
SymPy expression to print.
settings : args
Same as the settings accepted by SymPy's sstr().
Examples
========
>>> from sympy.physics.vector import vprint, dynamicsymbols
>>> u1 = dynamicsymbols('u1')
>>> print(u1)
u1(t)
>>> vprint(u1)
u1
"""
outstr = vsprint(expr, **settings)
import builtins
if (outstr != 'None'):
builtins._ = outstr
print(outstr)
def vsstrrepr(expr, **settings):
"""Function for displaying expression representation's with vector
printing enabled.
Parameters
==========
expr : valid SymPy object
SymPy expression to print.
settings : args
Same as the settings accepted by SymPy's sstrrepr().
"""
p = VectorStrReprPrinter(settings)
return p.doprint(expr)
def vsprint(expr, **settings):
r"""Function for displaying expressions generated in the
sympy.physics vector package.
Returns the output of vprint() as a string.
Parameters
==========
expr : valid SymPy object
SymPy expression to print
settings : args
Same as the settings accepted by SymPy's sstr().
Examples
========
>>> from sympy.physics.vector import vsprint, dynamicsymbols
>>> u1, u2 = dynamicsymbols('u1 u2')
>>> u2d = dynamicsymbols('u2', level=1)
>>> print("%s = %s" % (u1, u2 + u2d))
u1(t) = u2(t) + Derivative(u2(t), t)
>>> print("%s = %s" % (vsprint(u1), vsprint(u2 + u2d)))
u1 = u2 + u2'
"""
string_printer = VectorStrPrinter(settings)
return string_printer.doprint(expr)
def vpprint(expr, **settings):
r"""Function for pretty printing of expressions generated in the
sympy.physics vector package.
Mainly used for expressions not inside a vector; the output of running
scripts and generating equations of motion. Takes the same options as
SymPy's :func:`~.pretty_print`; see that function for more information.
Parameters
==========
expr : valid SymPy object
SymPy expression to pretty print
settings : args
Same as those accepted by SymPy's pretty_print.
"""
pp = VectorPrettyPrinter(settings)
# Note that this is copied from sympy.printing.pretty.pretty_print:
# XXX: this is an ugly hack, but at least it works
use_unicode = pp._settings['use_unicode']
from sympy.printing.pretty.pretty_symbology import pretty_use_unicode
uflag = pretty_use_unicode(use_unicode)
try:
return pp.doprint(expr)
finally:
pretty_use_unicode(uflag)
def vlatex(expr, **settings):
r"""Function for printing latex representation of sympy.physics.vector
objects.
For latex representation of Vectors, Dyadics, and dynamicsymbols. Takes the
same options as SymPy's :func:`~.latex`; see that function for more
information;
Parameters
==========
expr : valid SymPy object
SymPy expression to represent in LaTeX form
settings : args
Same as latex()
Examples
========
>>> from sympy.physics.vector import vlatex, ReferenceFrame, dynamicsymbols
>>> N = ReferenceFrame('N')
>>> q1, q2 = dynamicsymbols('q1 q2')
>>> q1d, q2d = dynamicsymbols('q1 q2', 1)
>>> q1dd, q2dd = dynamicsymbols('q1 q2', 2)
>>> vlatex(N.x + N.y)
'\\mathbf{\\hat{n}_x} + \\mathbf{\\hat{n}_y}'
>>> vlatex(q1 + q2)
'q_{1} + q_{2}'
>>> vlatex(q1d)
'\\dot{q}_{1}'
>>> vlatex(q1 * q2d)
'q_{1} \\dot{q}_{2}'
>>> vlatex(q1dd * q1 / q1d)
'\\frac{q_{1} \\ddot{q}_{1}}{\\dot{q}_{1}}'
"""
latex_printer = VectorLatexPrinter(settings)
return latex_printer.doprint(expr)
def init_vprinting(**kwargs):
"""Initializes time derivative printing for all SymPy objects, i.e. any
functions of time will be displayed in a more compact notation. The main
benefit of this is for printing of time derivatives; instead of
displaying as ``Derivative(f(t),t)``, it will display ``f'``. This is
only actually needed for when derivatives are present and are not in a
physics.vector.Vector or physics.vector.Dyadic object. This function is a
light wrapper to :func:`~.init_printing`. Any keyword
arguments for it are valid here.
{0}
Examples
========
>>> from sympy import Function, symbols
>>> t, x = symbols('t, x')
>>> omega = Function('omega')
>>> omega(x).diff()
Derivative(omega(x), x)
>>> omega(t).diff()
Derivative(omega(t), t)
Now use the string printer:
>>> from sympy.physics.vector import init_vprinting
>>> init_vprinting(pretty_print=False)
>>> omega(x).diff()
Derivative(omega(x), x)
>>> omega(t).diff()
omega'
"""
kwargs['str_printer'] = vsstrrepr
kwargs['pretty_printer'] = vpprint
kwargs['latex_printer'] = vlatex
init_printing(**kwargs)
params = init_printing.__doc__.split('Examples\n ========')[0] # type: ignore
init_vprinting.__doc__ = init_vprinting.__doc__.format(params) # type: ignore
PK ]ZZZ�g�#�a �a sympy/physics/vector/vector.pyfrom sympy import (S, sympify, expand, sqrt, Add, zeros, acos,
ImmutableMatrix as Matrix, simplify)
from sympy.simplify.trigsimp import trigsimp
from sympy.printing.defaults import Printable
from sympy.utilities.misc import filldedent
from sympy.core.evalf import EvalfMixin
from mpmath.libmp.libmpf import prec_to_dps
__all__ = ['Vector']
class Vector(Printable, EvalfMixin):
"""The class used to define vectors.
It along with ReferenceFrame are the building blocks of describing a
classical mechanics system in PyDy and sympy.physics.vector.
Attributes
==========
simp : Boolean
Let certain methods use trigsimp on their outputs
"""
simp = False
is_number = False
def __init__(self, inlist):
"""This is the constructor for the Vector class. You should not be
calling this, it should only be used by other functions. You should be
treating Vectors like you would with if you were doing the math by
hand, and getting the first 3 from the standard basis vectors from a
ReferenceFrame.
The only exception is to create a zero vector:
zv = Vector(0)
"""
self.args = []
if inlist == 0:
inlist = []
if isinstance(inlist, dict):
d = inlist
else:
d = {}
for inp in inlist:
if inp[1] in d:
d[inp[1]] += inp[0]
else:
d[inp[1]] = inp[0]
for k, v in d.items():
if v != Matrix([0, 0, 0]):
self.args.append((v, k))
@property
def func(self):
"""Returns the class Vector. """
return Vector
def __hash__(self):
return hash(tuple(self.args))
def __add__(self, other):
"""The add operator for Vector. """
if other == 0:
return self
other = _check_vector(other)
return Vector(self.args + other.args)
def dot(self, other):
"""Dot product of two vectors.
Returns a scalar, the dot product of the two Vectors
Parameters
==========
other : Vector
The Vector which we are dotting with
Examples
========
>>> from sympy.physics.vector import ReferenceFrame, dot
>>> from sympy import symbols
>>> q1 = symbols('q1')
>>> N = ReferenceFrame('N')
>>> dot(N.x, N.x)
1
>>> dot(N.x, N.y)
0
>>> A = N.orientnew('A', 'Axis', [q1, N.x])
>>> dot(N.y, A.y)
cos(q1)
"""
from sympy.physics.vector.dyadic import Dyadic, _check_dyadic
if isinstance(other, Dyadic):
other = _check_dyadic(other)
ol = Vector(0)
for v in other.args:
ol += v[0] * v[2] * (v[1].dot(self))
return ol
other = _check_vector(other)
out = S.Zero
for v1 in self.args:
for v2 in other.args:
out += ((v2[0].T) * (v2[1].dcm(v1[1])) * (v1[0]))[0]
if Vector.simp:
return trigsimp(out, recursive=True)
else:
return out
def __truediv__(self, other):
"""This uses mul and inputs self and 1 divided by other. """
return self.__mul__(S.One / other)
def __eq__(self, other):
"""Tests for equality.
It is very import to note that this is only as good as the SymPy
equality test; False does not always mean they are not equivalent
Vectors.
If other is 0, and self is empty, returns True.
If other is 0 and self is not empty, returns False.
If none of the above, only accepts other as a Vector.
"""
if other == 0:
other = Vector(0)
try:
other = _check_vector(other)
except TypeError:
return False
if (self.args == []) and (other.args == []):
return True
elif (self.args == []) or (other.args == []):
return False
frame = self.args[0][1]
for v in frame:
if expand((self - other).dot(v)) != 0:
return False
return True
def __mul__(self, other):
"""Multiplies the Vector by a sympifyable expression.
Parameters
==========
other : Sympifyable
The scalar to multiply this Vector with
Examples
========
>>> from sympy.physics.vector import ReferenceFrame
>>> from sympy import Symbol
>>> N = ReferenceFrame('N')
>>> b = Symbol('b')
>>> V = 10 * b * N.x
>>> print(V)
10*b*N.x
"""
newlist = list(self.args)
other = sympify(other)
for i, v in enumerate(newlist):
newlist[i] = (other * newlist[i][0], newlist[i][1])
return Vector(newlist)
def __neg__(self):
return self * -1
def outer(self, other):
"""Outer product between two Vectors.
A rank increasing operation, which returns a Dyadic from two Vectors
Parameters
==========
other : Vector
The Vector to take the outer product with
Examples
========
>>> from sympy.physics.vector import ReferenceFrame, outer
>>> N = ReferenceFrame('N')
>>> outer(N.x, N.x)
(N.x|N.x)
"""
from sympy.physics.vector.dyadic import Dyadic
other = _check_vector(other)
ol = Dyadic(0)
for v in self.args:
for v2 in other.args:
# it looks this way because if we are in the same frame and
# use the enumerate function on the same frame in a nested
# fashion, then bad things happen
ol += Dyadic([(v[0][0] * v2[0][0], v[1].x, v2[1].x)])
ol += Dyadic([(v[0][0] * v2[0][1], v[1].x, v2[1].y)])
ol += Dyadic([(v[0][0] * v2[0][2], v[1].x, v2[1].z)])
ol += Dyadic([(v[0][1] * v2[0][0], v[1].y, v2[1].x)])
ol += Dyadic([(v[0][1] * v2[0][1], v[1].y, v2[1].y)])
ol += Dyadic([(v[0][1] * v2[0][2], v[1].y, v2[1].z)])
ol += Dyadic([(v[0][2] * v2[0][0], v[1].z, v2[1].x)])
ol += Dyadic([(v[0][2] * v2[0][1], v[1].z, v2[1].y)])
ol += Dyadic([(v[0][2] * v2[0][2], v[1].z, v2[1].z)])
return ol
def _latex(self, printer):
"""Latex Printing method. """
ar = self.args # just to shorten things
if len(ar) == 0:
return str(0)
ol = [] # output list, to be concatenated to a string
for i, v in enumerate(ar):
for j in 0, 1, 2:
# if the coef of the basis vector is 1, we skip the 1
if ar[i][0][j] == 1:
ol.append(' + ' + ar[i][1].latex_vecs[j])
# if the coef of the basis vector is -1, we skip the 1
elif ar[i][0][j] == -1:
ol.append(' - ' + ar[i][1].latex_vecs[j])
elif ar[i][0][j] != 0:
# If the coefficient of the basis vector is not 1 or -1;
# also, we might wrap it in parentheses, for readability.
arg_str = printer._print(ar[i][0][j])
if isinstance(ar[i][0][j], Add):
arg_str = "(%s)" % arg_str
if arg_str[0] == '-':
arg_str = arg_str[1:]
str_start = ' - '
else:
str_start = ' + '
ol.append(str_start + arg_str + ar[i][1].latex_vecs[j])
outstr = ''.join(ol)
if outstr.startswith(' + '):
outstr = outstr[3:]
elif outstr.startswith(' '):
outstr = outstr[1:]
return outstr
def _pretty(self, printer):
"""Pretty Printing method. """
from sympy.printing.pretty.stringpict import prettyForm
terms = []
def juxtapose(a, b):
pa = printer._print(a)
pb = printer._print(b)
if a.is_Add:
pa = prettyForm(*pa.parens())
return printer._print_seq([pa, pb], delimiter=' ')
for M, N in self.args:
for i in range(3):
if M[i] == 0:
continue
elif M[i] == 1:
terms.append(prettyForm(N.pretty_vecs[i]))
elif M[i] == -1:
terms.append(prettyForm("-1") * prettyForm(N.pretty_vecs[i]))
else:
terms.append(juxtapose(M[i], N.pretty_vecs[i]))
if terms:
pretty_result = prettyForm.__add__(*terms)
else:
pretty_result = prettyForm("0")
return pretty_result
def __rsub__(self, other):
return (-1 * self) + other
def _sympystr(self, printer, order=True):
"""Printing method. """
if not order or len(self.args) == 1:
ar = list(self.args)
elif len(self.args) == 0:
return printer._print(0)
else:
d = {v[1]: v[0] for v in self.args}
keys = sorted(d.keys(), key=lambda x: x.index)
ar = []
for key in keys:
ar.append((d[key], key))
ol = [] # output list, to be concatenated to a string
for i, v in enumerate(ar):
for j in 0, 1, 2:
# if the coef of the basis vector is 1, we skip the 1
if ar[i][0][j] == 1:
ol.append(' + ' + ar[i][1].str_vecs[j])
# if the coef of the basis vector is -1, we skip the 1
elif ar[i][0][j] == -1:
ol.append(' - ' + ar[i][1].str_vecs[j])
elif ar[i][0][j] != 0:
# If the coefficient of the basis vector is not 1 or -1;
# also, we might wrap it in parentheses, for readability.
arg_str = printer._print(ar[i][0][j])
if isinstance(ar[i][0][j], Add):
arg_str = "(%s)" % arg_str
if arg_str[0] == '-':
arg_str = arg_str[1:]
str_start = ' - '
else:
str_start = ' + '
ol.append(str_start + arg_str + '*' + ar[i][1].str_vecs[j])
outstr = ''.join(ol)
if outstr.startswith(' + '):
outstr = outstr[3:]
elif outstr.startswith(' '):
outstr = outstr[1:]
return outstr
def __sub__(self, other):
"""The subtraction operator. """
return self.__add__(other * -1)
def cross(self, other):
"""The cross product operator for two Vectors.
Returns a Vector, expressed in the same ReferenceFrames as self.
Parameters
==========
other : Vector
The Vector which we are crossing with
Examples
========
>>> from sympy import symbols
>>> from sympy.physics.vector import ReferenceFrame, cross
>>> q1 = symbols('q1')
>>> N = ReferenceFrame('N')
>>> cross(N.x, N.y)
N.z
>>> A = ReferenceFrame('A')
>>> A.orient_axis(N, q1, N.x)
>>> cross(A.x, N.y)
N.z
>>> cross(N.y, A.x)
- sin(q1)*A.y - cos(q1)*A.z
"""
from sympy.physics.vector.dyadic import Dyadic, _check_dyadic
if isinstance(other, Dyadic):
other = _check_dyadic(other)
ol = Dyadic(0)
for i, v in enumerate(other.args):
ol += v[0] * ((self.cross(v[1])).outer(v[2]))
return ol
other = _check_vector(other)
if other.args == []:
return Vector(0)
def _det(mat):
"""This is needed as a little method for to find the determinant
of a list in python; needs to work for a 3x3 list.
SymPy's Matrix will not take in Vector, so need a custom function.
You should not be calling this.
"""
return (mat[0][0] * (mat[1][1] * mat[2][2] - mat[1][2] * mat[2][1])
+ mat[0][1] * (mat[1][2] * mat[2][0] - mat[1][0] *
mat[2][2]) + mat[0][2] * (mat[1][0] * mat[2][1] -
mat[1][1] * mat[2][0]))
outlist = []
ar = other.args # For brevity
for i, v in enumerate(ar):
tempx = v[1].x
tempy = v[1].y
tempz = v[1].z
tempm = ([[tempx, tempy, tempz],
[self.dot(tempx), self.dot(tempy), self.dot(tempz)],
[Vector([ar[i]]).dot(tempx), Vector([ar[i]]).dot(tempy),
Vector([ar[i]]).dot(tempz)]])
outlist += _det(tempm).args
return Vector(outlist)
__radd__ = __add__
__rmul__ = __mul__
def separate(self):
"""
The constituents of this vector in different reference frames,
as per its definition.
Returns a dict mapping each ReferenceFrame to the corresponding
constituent Vector.
Examples
========
>>> from sympy.physics.vector import ReferenceFrame
>>> R1 = ReferenceFrame('R1')
>>> R2 = ReferenceFrame('R2')
>>> v = R1.x + R2.x
>>> v.separate() == {R1: R1.x, R2: R2.x}
True
"""
components = {}
for x in self.args:
components[x[1]] = Vector([x])
return components
def __and__(self, other):
return self.dot(other)
__and__.__doc__ = dot.__doc__
__rand__ = __and__
def __xor__(self, other):
return self.cross(other)
__xor__.__doc__ = cross.__doc__
def __or__(self, other):
return self.outer(other)
__or__.__doc__ = outer.__doc__
def diff(self, var, frame, var_in_dcm=True):
"""Returns the partial derivative of the vector with respect to a
variable in the provided reference frame.
Parameters
==========
var : Symbol
What the partial derivative is taken with respect to.
frame : ReferenceFrame
The reference frame that the partial derivative is taken in.
var_in_dcm : boolean
If true, the differentiation algorithm assumes that the variable
may be present in any of the direction cosine matrices that relate
the frame to the frames of any component of the vector. But if it
is known that the variable is not present in the direction cosine
matrices, false can be set to skip full reexpression in the desired
frame.
Examples
========
>>> from sympy import Symbol
>>> from sympy.physics.vector import dynamicsymbols, ReferenceFrame
>>> from sympy.physics.vector import init_vprinting
>>> init_vprinting(pretty_print=False)
>>> t = Symbol('t')
>>> q1 = dynamicsymbols('q1')
>>> N = ReferenceFrame('N')
>>> A = N.orientnew('A', 'Axis', [q1, N.y])
>>> A.x.diff(t, N)
- sin(q1)*q1'*N.x - cos(q1)*q1'*N.z
>>> A.x.diff(t, N).express(A).simplify()
- q1'*A.z
>>> B = ReferenceFrame('B')
>>> u1, u2 = dynamicsymbols('u1, u2')
>>> v = u1 * A.x + u2 * B.y
>>> v.diff(u2, N, var_in_dcm=False)
B.y
"""
from sympy.physics.vector.frame import _check_frame
_check_frame(frame)
var = sympify(var)
inlist = []
for vector_component in self.args:
measure_number = vector_component[0]
component_frame = vector_component[1]
if component_frame == frame:
inlist += [(measure_number.diff(var), frame)]
else:
# If the direction cosine matrix relating the component frame
# with the derivative frame does not contain the variable.
if not var_in_dcm or (frame.dcm(component_frame).diff(var) ==
zeros(3, 3)):
inlist += [(measure_number.diff(var), component_frame)]
else: # else express in the frame
reexp_vec_comp = Vector([vector_component]).express(frame)
deriv = reexp_vec_comp.args[0][0].diff(var)
inlist += Vector([(deriv, frame)]).args
return Vector(inlist)
def express(self, otherframe, variables=False):
"""
Returns a Vector equivalent to this one, expressed in otherframe.
Uses the global express method.
Parameters
==========
otherframe : ReferenceFrame
The frame for this Vector to be described in
variables : boolean
If True, the coordinate symbols(if present) in this Vector
are re-expressed in terms otherframe
Examples
========
>>> from sympy.physics.vector import ReferenceFrame, dynamicsymbols
>>> from sympy.physics.vector import init_vprinting
>>> init_vprinting(pretty_print=False)
>>> q1 = dynamicsymbols('q1')
>>> N = ReferenceFrame('N')
>>> A = N.orientnew('A', 'Axis', [q1, N.y])
>>> A.x.express(N)
cos(q1)*N.x - sin(q1)*N.z
"""
from sympy.physics.vector import express
return express(self, otherframe, variables=variables)
def to_matrix(self, reference_frame):
"""Returns the matrix form of the vector with respect to the given
frame.
Parameters
----------
reference_frame : ReferenceFrame
The reference frame that the rows of the matrix correspond to.
Returns
-------
matrix : ImmutableMatrix, shape(3,1)
The matrix that gives the 1D vector.
Examples
========
>>> from sympy import symbols
>>> from sympy.physics.vector import ReferenceFrame
>>> a, b, c = symbols('a, b, c')
>>> N = ReferenceFrame('N')
>>> vector = a * N.x + b * N.y + c * N.z
>>> vector.to_matrix(N)
Matrix([
[a],
[b],
[c]])
>>> beta = symbols('beta')
>>> A = N.orientnew('A', 'Axis', (beta, N.x))
>>> vector.to_matrix(A)
Matrix([
[ a],
[ b*cos(beta) + c*sin(beta)],
[-b*sin(beta) + c*cos(beta)]])
"""
return Matrix([self.dot(unit_vec) for unit_vec in
reference_frame]).reshape(3, 1)
def doit(self, **hints):
"""Calls .doit() on each term in the Vector"""
d = {}
for v in self.args:
d[v[1]] = v[0].applyfunc(lambda x: x.doit(**hints))
return Vector(d)
def dt(self, otherframe):
"""
Returns a Vector which is the time derivative of
the self Vector, taken in frame otherframe.
Calls the global time_derivative method
Parameters
==========
otherframe : ReferenceFrame
The frame to calculate the time derivative in
"""
from sympy.physics.vector import time_derivative
return time_derivative(self, otherframe)
def simplify(self):
"""Returns a simplified Vector."""
d = {}
for v in self.args:
d[v[1]] = simplify(v[0])
return Vector(d)
def subs(self, *args, **kwargs):
"""Substitution on the Vector.
Examples
========
>>> from sympy.physics.vector import ReferenceFrame
>>> from sympy import Symbol
>>> N = ReferenceFrame('N')
>>> s = Symbol('s')
>>> a = N.x * s
>>> a.subs({s: 2})
2*N.x
"""
d = {}
for v in self.args:
d[v[1]] = v[0].subs(*args, **kwargs)
return Vector(d)
def magnitude(self):
"""Returns the magnitude (Euclidean norm) of self.
Warnings
========
Python ignores the leading negative sign so that might
give wrong results.
``-A.x.magnitude()`` would be treated as ``-(A.x.magnitude())``,
instead of ``(-A.x).magnitude()``.
"""
return sqrt(self.dot(self))
def normalize(self):
"""Returns a Vector of magnitude 1, codirectional with self."""
return Vector(self.args + []) / self.magnitude()
def applyfunc(self, f):
"""Apply a function to each component of a vector."""
if not callable(f):
raise TypeError("`f` must be callable.")
d = {}
for v in self.args:
d[v[1]] = v[0].applyfunc(f)
return Vector(d)
def angle_between(self, vec):
"""
Returns the smallest angle between Vector 'vec' and self.
Parameter
=========
vec : Vector
The Vector between which angle is needed.
Examples
========
>>> from sympy.physics.vector import ReferenceFrame
>>> A = ReferenceFrame("A")
>>> v1 = A.x
>>> v2 = A.y
>>> v1.angle_between(v2)
pi/2
>>> v3 = A.x + A.y + A.z
>>> v1.angle_between(v3)
acos(sqrt(3)/3)
Warnings
========
Python ignores the leading negative sign so that might give wrong
results. ``-A.x.angle_between()`` would be treated as
``-(A.x.angle_between())``, instead of ``(-A.x).angle_between()``.
"""
vec1 = self.normalize()
vec2 = vec.normalize()
angle = acos(vec1.dot(vec2))
return angle
def free_symbols(self, reference_frame):
"""Returns the free symbols in the measure numbers of the vector
expressed in the given reference frame.
Parameters
==========
reference_frame : ReferenceFrame
The frame with respect to which the free symbols of the given
vector is to be determined.
Returns
=======
set of Symbol
set of symbols present in the measure numbers of
``reference_frame``.
"""
return self.to_matrix(reference_frame).free_symbols
def free_dynamicsymbols(self, reference_frame):
"""Returns the free dynamic symbols (functions of time ``t``) in the
measure numbers of the vector expressed in the given reference frame.
Parameters
==========
reference_frame : ReferenceFrame
The frame with respect to which the free dynamic symbols of the
given vector is to be determined.
Returns
=======
set
Set of functions of time ``t``, e.g.
``Function('f')(me.dynamicsymbols._t)``.
"""
# TODO : Circular dependency if imported at top. Should move
# find_dynamicsymbols into physics.vector.functions.
from sympy.physics.mechanics.functions import find_dynamicsymbols
return find_dynamicsymbols(self, reference_frame=reference_frame)
def _eval_evalf(self, prec):
if not self.args:
return self
new_args = []
dps = prec_to_dps(prec)
for mat, frame in self.args:
new_args.append([mat.evalf(n=dps), frame])
return Vector(new_args)
def xreplace(self, rule):
"""Replace occurrences of objects within the measure numbers of the
vector.
Parameters
==========
rule : dict-like
Expresses a replacement rule.
Returns
=======
Vector
Result of the replacement.
Examples
========
>>> from sympy import symbols, pi
>>> from sympy.physics.vector import ReferenceFrame
>>> A = ReferenceFrame('A')
>>> x, y, z = symbols('x y z')
>>> ((1 + x*y) * A.x).xreplace({x: pi})
(pi*y + 1)*A.x
>>> ((1 + x*y) * A.x).xreplace({x: pi, y: 2})
(1 + 2*pi)*A.x
Replacements occur only if an entire node in the expression tree is
matched:
>>> ((x*y + z) * A.x).xreplace({x*y: pi})
(z + pi)*A.x
>>> ((x*y*z) * A.x).xreplace({x*y: pi})
x*y*z*A.x
"""
new_args = []
for mat, frame in self.args:
mat = mat.xreplace(rule)
new_args.append([mat, frame])
return Vector(new_args)
class VectorTypeError(TypeError):
def __init__(self, other, want):
msg = filldedent("Expected an instance of %s, but received object "
"'%s' of %s." % (type(want), other, type(other)))
super().__init__(msg)
def _check_vector(other):
if not isinstance(other, Vector):
raise TypeError('A Vector must be supplied')
return other
PK ]ZZZ�K!� sympy/plotting/__init__.pyfrom .plot import plot_backends
from .plot_implicit import plot_implicit
from .textplot import textplot
from .pygletplot import PygletPlot
from .plot import PlotGrid
from .plot import (plot, plot_parametric, plot3d, plot3d_parametric_surface,
plot3d_parametric_line, plot_contour)
__all__ = [
'plot_backends',
'plot_implicit',
'textplot',
'PygletPlot',
'PlotGrid',
'plot', 'plot_parametric', 'plot3d', 'plot3d_parametric_surface',
'plot3d_parametric_line', 'plot_contour'
]
PK ]ZZZ���,Y ,Y ' sympy/plotting/experimental_lambdify.py""" rewrite of lambdify - This stuff is not stable at all.
It is for internal use in the new plotting module.
It may (will! see the Q'n'A in the source) be rewritten.
It's completely self contained. Especially it does not use lambdarepr.
It does not aim to replace the current lambdify. Most importantly it will never
ever support anything else than SymPy expressions (no Matrices, dictionaries
and so on).
"""
import re
from sympy.core.numbers import (I, NumberSymbol, oo, zoo)
from sympy.core.symbol import Symbol
from sympy.utilities.iterables import numbered_symbols
# We parse the expression string into a tree that identifies functions. Then
# we translate the names of the functions and we translate also some strings
# that are not names of functions (all this according to translation
# dictionaries).
# If the translation goes to another module (like numpy) the
# module is imported and 'func' is translated to 'module.func'.
# If a function can not be translated, the inner nodes of that part of the
# tree are not translated. So if we have Integral(sqrt(x)), sqrt is not
# translated to np.sqrt and the Integral does not crash.
# A namespace for all this is generated by crawling the (func, args) tree of
# the expression. The creation of this namespace involves many ugly
# workarounds.
# The namespace consists of all the names needed for the SymPy expression and
# all the name of modules used for translation. Those modules are imported only
# as a name (import numpy as np) in order to keep the namespace small and
# manageable.
# Please, if there is a bug, do not try to fix it here! Rewrite this by using
# the method proposed in the last Q'n'A below. That way the new function will
# work just as well, be just as simple, but it wont need any new workarounds.
# If you insist on fixing it here, look at the workarounds in the function
# sympy_expression_namespace and in lambdify.
# Q: Why are you not using Python abstract syntax tree?
# A: Because it is more complicated and not much more powerful in this case.
# Q: What if I have Symbol('sin') or g=Function('f')?
# A: You will break the algorithm. We should use srepr to defend against this?
# The problem with Symbol('sin') is that it will be printed as 'sin'. The
# parser will distinguish it from the function 'sin' because functions are
# detected thanks to the opening parenthesis, but the lambda expression won't
# understand the difference if we have also the sin function.
# The solution (complicated) is to use srepr and maybe ast.
# The problem with the g=Function('f') is that it will be printed as 'f' but in
# the global namespace we have only 'g'. But as the same printer is used in the
# constructor of the namespace there will be no problem.
# Q: What if some of the printers are not printing as expected?
# A: The algorithm wont work. You must use srepr for those cases. But even
# srepr may not print well. All problems with printers should be considered
# bugs.
# Q: What about _imp_ functions?
# A: Those are taken care for by evalf. A special case treatment will work
# faster but it's not worth the code complexity.
# Q: Will ast fix all possible problems?
# A: No. You will always have to use some printer. Even srepr may not work in
# some cases. But if the printer does not work, that should be considered a
# bug.
# Q: Is there same way to fix all possible problems?
# A: Probably by constructing our strings ourself by traversing the (func,
# args) tree and creating the namespace at the same time. That actually sounds
# good.
from sympy.external import import_module
import warnings
#TODO debugging output
class vectorized_lambdify:
""" Return a sufficiently smart, vectorized and lambdified function.
Returns only reals.
Explanation
===========
This function uses experimental_lambdify to created a lambdified
expression ready to be used with numpy. Many of the functions in SymPy
are not implemented in numpy so in some cases we resort to Python cmath or
even to evalf.
The following translations are tried:
only numpy complex
- on errors raised by SymPy trying to work with ndarray:
only Python cmath and then vectorize complex128
When using Python cmath there is no need for evalf or float/complex
because Python cmath calls those.
This function never tries to mix numpy directly with evalf because numpy
does not understand SymPy Float. If this is needed one can use the
float_wrap_evalf/complex_wrap_evalf options of experimental_lambdify or
better one can be explicit about the dtypes that numpy works with.
Check numpy bug http://projects.scipy.org/numpy/ticket/1013 to know what
types of errors to expect.
"""
def __init__(self, args, expr):
self.args = args
self.expr = expr
self.np = import_module('numpy')
self.lambda_func_1 = experimental_lambdify(
args, expr, use_np=True)
self.vector_func_1 = self.lambda_func_1
self.lambda_func_2 = experimental_lambdify(
args, expr, use_python_cmath=True)
self.vector_func_2 = self.np.vectorize(
self.lambda_func_2, otypes=[complex])
self.vector_func = self.vector_func_1
self.failure = False
def __call__(self, *args):
np = self.np
try:
temp_args = (np.array(a, dtype=complex) for a in args)
results = self.vector_func(*temp_args)
results = np.ma.masked_where(
np.abs(results.imag) > 1e-7 * np.abs(results),
results.real, copy=False)
return results
except ValueError:
if self.failure:
raise
self.failure = True
self.vector_func = self.vector_func_2
warnings.warn(
'The evaluation of the expression is problematic. '
'We are trying a failback method that may still work. '
'Please report this as a bug.')
return self.__call__(*args)
class lambdify:
"""Returns the lambdified function.
Explanation
===========
This function uses experimental_lambdify to create a lambdified
expression. It uses cmath to lambdify the expression. If the function
is not implemented in Python cmath, Python cmath calls evalf on those
functions.
"""
def __init__(self, args, expr):
self.args = args
self.expr = expr
self.lambda_func_1 = experimental_lambdify(
args, expr, use_python_cmath=True, use_evalf=True)
self.lambda_func_2 = experimental_lambdify(
args, expr, use_python_math=True, use_evalf=True)
self.lambda_func_3 = experimental_lambdify(
args, expr, use_evalf=True, complex_wrap_evalf=True)
self.lambda_func = self.lambda_func_1
self.failure = False
def __call__(self, args):
try:
#The result can be sympy.Float. Hence wrap it with complex type.
result = complex(self.lambda_func(args))
if abs(result.imag) > 1e-7 * abs(result):
return None
return result.real
except (ZeroDivisionError, OverflowError):
return None
except TypeError as e:
if self.failure:
raise e
if self.lambda_func == self.lambda_func_1:
self.lambda_func = self.lambda_func_2
return self.__call__(args)
self.failure = True
self.lambda_func = self.lambda_func_3
warnings.warn(
'The evaluation of the expression is problematic. '
'We are trying a failback method that may still work. '
'Please report this as a bug.', stacklevel=2)
return self.__call__(args)
def experimental_lambdify(*args, **kwargs):
l = Lambdifier(*args, **kwargs)
return l
class Lambdifier:
def __init__(self, args, expr, print_lambda=False, use_evalf=False,
float_wrap_evalf=False, complex_wrap_evalf=False,
use_np=False, use_python_math=False, use_python_cmath=False,
use_interval=False):
self.print_lambda = print_lambda
self.use_evalf = use_evalf
self.float_wrap_evalf = float_wrap_evalf
self.complex_wrap_evalf = complex_wrap_evalf
self.use_np = use_np
self.use_python_math = use_python_math
self.use_python_cmath = use_python_cmath
self.use_interval = use_interval
# Constructing the argument string
# - check
if not all(isinstance(a, Symbol) for a in args):
raise ValueError('The arguments must be Symbols.')
# - use numbered symbols
syms = numbered_symbols(exclude=expr.free_symbols)
newargs = [next(syms) for _ in args]
expr = expr.xreplace(dict(zip(args, newargs)))
argstr = ', '.join([str(a) for a in newargs])
del syms, newargs, args
# Constructing the translation dictionaries and making the translation
self.dict_str = self.get_dict_str()
self.dict_fun = self.get_dict_fun()
exprstr = str(expr)
newexpr = self.tree2str_translate(self.str2tree(exprstr))
# Constructing the namespaces
namespace = {}
namespace.update(self.sympy_atoms_namespace(expr))
namespace.update(self.sympy_expression_namespace(expr))
# XXX Workaround
# Ugly workaround because Pow(a,Half) prints as sqrt(a)
# and sympy_expression_namespace can not catch it.
from sympy.functions.elementary.miscellaneous import sqrt
namespace.update({'sqrt': sqrt})
namespace.update({'Eq': lambda x, y: x == y})
namespace.update({'Ne': lambda x, y: x != y})
# End workaround.
if use_python_math:
namespace.update({'math': __import__('math')})
if use_python_cmath:
namespace.update({'cmath': __import__('cmath')})
if use_np:
try:
namespace.update({'np': __import__('numpy')})
except ImportError:
raise ImportError(
'experimental_lambdify failed to import numpy.')
if use_interval:
namespace.update({'imath': __import__(
'sympy.plotting.intervalmath', fromlist=['intervalmath'])})
namespace.update({'math': __import__('math')})
# Construct the lambda
if self.print_lambda:
print(newexpr)
eval_str = 'lambda %s : ( %s )' % (argstr, newexpr)
self.eval_str = eval_str
exec("MYNEWLAMBDA = %s" % eval_str, namespace)
self.lambda_func = namespace['MYNEWLAMBDA']
def __call__(self, *args, **kwargs):
return self.lambda_func(*args, **kwargs)
##############################################################################
# Dicts for translating from SymPy to other modules
##############################################################################
###
# builtins
###
# Functions with different names in builtins
builtin_functions_different = {
'Min': 'min',
'Max': 'max',
'Abs': 'abs',
}
# Strings that should be translated
builtin_not_functions = {
'I': '1j',
# 'oo': '1e400',
}
###
# numpy
###
# Functions that are the same in numpy
numpy_functions_same = [
'sin', 'cos', 'tan', 'sinh', 'cosh', 'tanh', 'exp', 'log',
'sqrt', 'floor', 'conjugate', 'sign',
]
# Functions with different names in numpy
numpy_functions_different = {
"acos": "arccos",
"acosh": "arccosh",
"arg": "angle",
"asin": "arcsin",
"asinh": "arcsinh",
"atan": "arctan",
"atan2": "arctan2",
"atanh": "arctanh",
"ceiling": "ceil",
"im": "imag",
"ln": "log",
"Max": "amax",
"Min": "amin",
"re": "real",
"Abs": "abs",
}
# Strings that should be translated
numpy_not_functions = {
'pi': 'np.pi',
'oo': 'np.inf',
'E': 'np.e',
}
###
# Python math
###
# Functions that are the same in math
math_functions_same = [
'sin', 'cos', 'tan', 'asin', 'acos', 'atan', 'atan2',
'sinh', 'cosh', 'tanh', 'asinh', 'acosh', 'atanh',
'exp', 'log', 'erf', 'sqrt', 'floor', 'factorial', 'gamma',
]
# Functions with different names in math
math_functions_different = {
'ceiling': 'ceil',
'ln': 'log',
'loggamma': 'lgamma'
}
# Strings that should be translated
math_not_functions = {
'pi': 'math.pi',
'E': 'math.e',
}
###
# Python cmath
###
# Functions that are the same in cmath
cmath_functions_same = [
'sin', 'cos', 'tan', 'asin', 'acos', 'atan',
'sinh', 'cosh', 'tanh', 'asinh', 'acosh', 'atanh',
'exp', 'log', 'sqrt',
]
# Functions with different names in cmath
cmath_functions_different = {
'ln': 'log',
'arg': 'phase',
}
# Strings that should be translated
cmath_not_functions = {
'pi': 'cmath.pi',
'E': 'cmath.e',
}
###
# intervalmath
###
interval_not_functions = {
'pi': 'math.pi',
'E': 'math.e'
}
interval_functions_same = [
'sin', 'cos', 'exp', 'tan', 'atan', 'log',
'sqrt', 'cosh', 'sinh', 'tanh', 'floor',
'acos', 'asin', 'acosh', 'asinh', 'atanh',
'Abs', 'And', 'Or'
]
interval_functions_different = {
'Min': 'imin',
'Max': 'imax',
'ceiling': 'ceil',
}
###
# mpmath, etc
###
#TODO
###
# Create the final ordered tuples of dictionaries
###
# For strings
def get_dict_str(self):
dict_str = dict(self.builtin_not_functions)
if self.use_np:
dict_str.update(self.numpy_not_functions)
if self.use_python_math:
dict_str.update(self.math_not_functions)
if self.use_python_cmath:
dict_str.update(self.cmath_not_functions)
if self.use_interval:
dict_str.update(self.interval_not_functions)
return dict_str
# For functions
def get_dict_fun(self):
dict_fun = dict(self.builtin_functions_different)
if self.use_np:
for s in self.numpy_functions_same:
dict_fun[s] = 'np.' + s
for k, v in self.numpy_functions_different.items():
dict_fun[k] = 'np.' + v
if self.use_python_math:
for s in self.math_functions_same:
dict_fun[s] = 'math.' + s
for k, v in self.math_functions_different.items():
dict_fun[k] = 'math.' + v
if self.use_python_cmath:
for s in self.cmath_functions_same:
dict_fun[s] = 'cmath.' + s
for k, v in self.cmath_functions_different.items():
dict_fun[k] = 'cmath.' + v
if self.use_interval:
for s in self.interval_functions_same:
dict_fun[s] = 'imath.' + s
for k, v in self.interval_functions_different.items():
dict_fun[k] = 'imath.' + v
return dict_fun
##############################################################################
# The translator functions, tree parsers, etc.
##############################################################################
def str2tree(self, exprstr):
"""Converts an expression string to a tree.
Explanation
===========
Functions are represented by ('func_name(', tree_of_arguments).
Other expressions are (head_string, mid_tree, tail_str).
Expressions that do not contain functions are directly returned.
Examples
========
>>> from sympy.abc import x, y, z
>>> from sympy import Integral, sin
>>> from sympy.plotting.experimental_lambdify import Lambdifier
>>> str2tree = Lambdifier([x], x).str2tree
>>> str2tree(str(Integral(x, (x, 1, y))))
('', ('Integral(', 'x, (x, 1, y)'), ')')
>>> str2tree(str(x+y))
'x + y'
>>> str2tree(str(x+y*sin(z)+1))
('x + y*', ('sin(', 'z'), ') + 1')
>>> str2tree('sin(y*(y + 1.1) + (sin(y)))')
('', ('sin(', ('y*(y + 1.1) + (', ('sin(', 'y'), '))')), ')')
"""
#matches the first 'function_name('
first_par = re.search(r'(\w+\()', exprstr)
if first_par is None:
return exprstr
else:
start = first_par.start()
end = first_par.end()
head = exprstr[:start]
func = exprstr[start:end]
tail = exprstr[end:]
count = 0
for i, c in enumerate(tail):
if c == '(':
count += 1
elif c == ')':
count -= 1
if count == -1:
break
func_tail = self.str2tree(tail[:i])
tail = self.str2tree(tail[i:])
return (head, (func, func_tail), tail)
@classmethod
def tree2str(cls, tree):
"""Converts a tree to string without translations.
Examples
========
>>> from sympy.abc import x, y, z
>>> from sympy import sin
>>> from sympy.plotting.experimental_lambdify import Lambdifier
>>> str2tree = Lambdifier([x], x).str2tree
>>> tree2str = Lambdifier([x], x).tree2str
>>> tree2str(str2tree(str(x+y*sin(z)+1)))
'x + y*sin(z) + 1'
"""
if isinstance(tree, str):
return tree
else:
return ''.join(map(cls.tree2str, tree))
def tree2str_translate(self, tree):
"""Converts a tree to string with translations.
Explanation
===========
Function names are translated by translate_func.
Other strings are translated by translate_str.
"""
if isinstance(tree, str):
return self.translate_str(tree)
elif isinstance(tree, tuple) and len(tree) == 2:
return self.translate_func(tree[0][:-1], tree[1])
else:
return ''.join([self.tree2str_translate(t) for t in tree])
def translate_str(self, estr):
"""Translate substrings of estr using in order the dictionaries in
dict_tuple_str."""
for pattern, repl in self.dict_str.items():
estr = re.sub(pattern, repl, estr)
return estr
def translate_func(self, func_name, argtree):
"""Translate function names and the tree of arguments.
Explanation
===========
If the function name is not in the dictionaries of dict_tuple_fun then the
function is surrounded by a float((...).evalf()).
The use of float is necessary as np.<function>(sympy.Float(..)) raises an
error."""
if func_name in self.dict_fun:
new_name = self.dict_fun[func_name]
argstr = self.tree2str_translate(argtree)
return new_name + '(' + argstr
elif func_name in ['Eq', 'Ne']:
op = {'Eq': '==', 'Ne': '!='}
return "(lambda x, y: x {} y)({}".format(op[func_name], self.tree2str_translate(argtree))
else:
template = '(%s(%s)).evalf(' if self.use_evalf else '%s(%s'
if self.float_wrap_evalf:
template = 'float(%s)' % template
elif self.complex_wrap_evalf:
template = 'complex(%s)' % template
# Wrapping should only happen on the outermost expression, which
# is the only thing we know will be a number.
float_wrap_evalf = self.float_wrap_evalf
complex_wrap_evalf = self.complex_wrap_evalf
self.float_wrap_evalf = False
self.complex_wrap_evalf = False
ret = template % (func_name, self.tree2str_translate(argtree))
self.float_wrap_evalf = float_wrap_evalf
self.complex_wrap_evalf = complex_wrap_evalf
return ret
##############################################################################
# The namespace constructors
##############################################################################
@classmethod
def sympy_expression_namespace(cls, expr):
"""Traverses the (func, args) tree of an expression and creates a SymPy
namespace. All other modules are imported only as a module name. That way
the namespace is not polluted and rests quite small. It probably causes much
more variable lookups and so it takes more time, but there are no tests on
that for the moment."""
if expr is None:
return {}
else:
funcname = str(expr.func)
# XXX Workaround
# Here we add an ugly workaround because str(func(x))
# is not always the same as str(func). Eg
# >>> str(Integral(x))
# "Integral(x)"
# >>> str(Integral)
# "<class 'sympy.integrals.integrals.Integral'>"
# >>> str(sqrt(x))
# "sqrt(x)"
# >>> str(sqrt)
# "<function sqrt at 0x3d92de8>"
# >>> str(sin(x))
# "sin(x)"
# >>> str(sin)
# "sin"
# Either one of those can be used but not all at the same time.
# The code considers the sin example as the right one.
regexlist = [
r'<class \'sympy[\w.]*?.([\w]*)\'>$',
# the example Integral
r'<function ([\w]*) at 0x[\w]*>$', # the example sqrt
]
for r in regexlist:
m = re.match(r, funcname)
if m is not None:
funcname = m.groups()[0]
# End of the workaround
# XXX debug: print funcname
args_dict = {}
for a in expr.args:
if (isinstance(a, (Symbol, NumberSymbol)) or a in [I, zoo, oo]):
continue
else:
args_dict.update(cls.sympy_expression_namespace(a))
args_dict.update({funcname: expr.func})
return args_dict
@staticmethod
def sympy_atoms_namespace(expr):
"""For no real reason this function is separated from
sympy_expression_namespace. It can be moved to it."""
atoms = expr.atoms(Symbol, NumberSymbol, I, zoo, oo)
d = {}
for a in atoms:
# XXX debug: print 'atom:' + str(a)
d[str(a)] = a
return d
PK ]ZZZ(���9� 9� sympy/plotting/plot.py"""Plotting module for SymPy.
A plot is represented by the ``Plot`` class that contains a reference to the
backend and a list of the data series to be plotted. The data series are
instances of classes meant to simplify getting points and meshes from SymPy
expressions. ``plot_backends`` is a dictionary with all the backends.
This module gives only the essential. For all the fancy stuff use directly
the backend. You can get the backend wrapper for every plot from the
``_backend`` attribute. Moreover the data series classes have various useful
methods like ``get_points``, ``get_meshes``, etc, that may
be useful if you wish to use another plotting library.
Especially if you need publication ready graphs and this module is not enough
for you - just get the ``_backend`` attribute and add whatever you want
directly to it. In the case of matplotlib (the common way to graph data in
python) just copy ``_backend.fig`` which is the figure and ``_backend.ax``
which is the axis and work on them as you would on any other matplotlib object.
Simplicity of code takes much greater importance than performance. Do not use it
if you care at all about performance. A new backend instance is initialized
every time you call ``show()`` and the old one is left to the garbage collector.
"""
from sympy.concrete.summations import Sum
from sympy.core.containers import Tuple
from sympy.core.expr import Expr
from sympy.core.function import Function, AppliedUndef
from sympy.core.symbol import (Dummy, Symbol, Wild)
from sympy.external import import_module
from sympy.functions import sign
from sympy.plotting.backends.base_backend import Plot
from sympy.plotting.backends.matplotlibbackend import MatplotlibBackend
from sympy.plotting.backends.textbackend import TextBackend
from sympy.plotting.series import (
LineOver1DRangeSeries, Parametric2DLineSeries, Parametric3DLineSeries,
ParametricSurfaceSeries, SurfaceOver2DRangeSeries, ContourSeries)
from sympy.plotting.utils import _check_arguments, _plot_sympify
from sympy.tensor.indexed import Indexed
# to maintain back-compatibility
from sympy.plotting.plotgrid import PlotGrid # noqa: F401
from sympy.plotting.series import BaseSeries # noqa: F401
from sympy.plotting.series import Line2DBaseSeries # noqa: F401
from sympy.plotting.series import Line3DBaseSeries # noqa: F401
from sympy.plotting.series import SurfaceBaseSeries # noqa: F401
from sympy.plotting.series import List2DSeries # noqa: F401
from sympy.plotting.series import GenericDataSeries # noqa: F401
from sympy.plotting.series import centers_of_faces # noqa: F401
from sympy.plotting.series import centers_of_segments # noqa: F401
from sympy.plotting.series import flat # noqa: F401
from sympy.plotting.backends.base_backend import unset_show # noqa: F401
from sympy.plotting.backends.matplotlibbackend import _matplotlib_list # noqa: F401
from sympy.plotting.textplot import textplot # noqa: F401
__doctest_requires__ = {
('plot3d',
'plot3d_parametric_line',
'plot3d_parametric_surface',
'plot_parametric'): ['matplotlib'],
# XXX: The plot doctest possibly should not require matplotlib. It fails at
# plot(x**2, (x, -5, 5)) which should be fine for text backend.
('plot',): ['matplotlib'],
}
def _process_summations(sum_bound, *args):
"""Substitute oo (infinity) in the lower/upper bounds of a summation with
some integer number.
Parameters
==========
sum_bound : int
oo will be substituted with this integer number.
*args : list/tuple
pre-processed arguments of the form (expr, range, ...)
Notes
=====
Let's consider the following summation: ``Sum(1 / x**2, (x, 1, oo))``.
The current implementation of lambdify (SymPy 1.12 at the time of
writing this) will create something of this form:
``sum(1 / x**2 for x in range(1, INF))``
The problem is that ``type(INF)`` is float, while ``range`` requires
integers: the evaluation fails.
Instead of modifying ``lambdify`` (which requires a deep knowledge), just
replace it with some integer number.
"""
def new_bound(t, bound):
if (not t.is_number) or t.is_finite:
return t
if sign(t) >= 0:
return bound
return -bound
args = list(args)
expr = args[0]
# select summations whose lower/upper bound is infinity
w = Wild("w", properties=[
lambda t: isinstance(t, Sum),
lambda t: any((not a[1].is_finite) or (not a[2].is_finite) for i, a in enumerate(t.args) if i > 0)
])
for t in list(expr.find(w)):
sums_args = list(t.args)
for i, a in enumerate(sums_args):
if i > 0:
sums_args[i] = (a[0], new_bound(a[1], sum_bound),
new_bound(a[2], sum_bound))
s = Sum(*sums_args)
expr = expr.subs(t, s)
args[0] = expr
return args
def _build_line_series(*args, **kwargs):
"""Loop over the provided arguments and create the necessary line series.
"""
series = []
sum_bound = int(kwargs.get("sum_bound", 1000))
for arg in args:
expr, r, label, rendering_kw = arg
kw = kwargs.copy()
if rendering_kw is not None:
kw["rendering_kw"] = rendering_kw
# TODO: _process_piecewise check goes here
if not callable(expr):
arg = _process_summations(sum_bound, *arg)
series.append(LineOver1DRangeSeries(*arg[:-1], **kw))
return series
def _create_series(series_type, plot_expr, **kwargs):
"""Extract the rendering_kw dictionary from the provided arguments and
create an appropriate data series.
"""
series = []
for args in plot_expr:
kw = kwargs.copy()
if args[-1] is not None:
kw["rendering_kw"] = args[-1]
series.append(series_type(*args[:-1], **kw))
return series
def _set_labels(series, labels, rendering_kw):
"""Apply the `label` and `rendering_kw` keyword arguments to the series.
"""
if not isinstance(labels, (list, tuple)):
labels = [labels]
if len(labels) > 0:
if len(labels) == 1 and len(series) > 1:
# if one label is provided and multiple series are being plotted,
# set the same label to all data series. It maintains
# back-compatibility
labels *= len(series)
if len(series) != len(labels):
raise ValueError("The number of labels must be equal to the "
"number of expressions being plotted.\nReceived "
f"{len(series)} expressions and {len(labels)} labels")
for s, l in zip(series, labels):
s.label = l
if rendering_kw:
if isinstance(rendering_kw, dict):
rendering_kw = [rendering_kw]
if len(rendering_kw) == 1:
rendering_kw *= len(series)
elif len(series) != len(rendering_kw):
raise ValueError("The number of rendering dictionaries must be "
"equal to the number of expressions being plotted.\nReceived "
f"{len(series)} expressions and {len(labels)} labels")
for s, r in zip(series, rendering_kw):
s.rendering_kw = r
def plot_factory(*args, **kwargs):
backend = kwargs.pop("backend", "default")
if isinstance(backend, str):
if backend == "default":
matplotlib = import_module('matplotlib',
min_module_version='1.1.0', catch=(RuntimeError,))
if matplotlib:
return MatplotlibBackend(*args, **kwargs)
return TextBackend(*args, **kwargs)
return plot_backends[backend](*args, **kwargs)
elif (type(backend) == type) and issubclass(backend, Plot):
return backend(*args, **kwargs)
else:
raise TypeError("backend must be either a string or a subclass of ``Plot``.")
plot_backends = {
'matplotlib': MatplotlibBackend,
'text': TextBackend,
}
####New API for plotting module ####
# TODO: Add color arrays for plots.
# TODO: Add more plotting options for 3d plots.
# TODO: Adaptive sampling for 3D plots.
def plot(*args, show=True, **kwargs):
"""Plots a function of a single variable as a curve.
Parameters
==========
args :
The first argument is the expression representing the function
of single variable to be plotted.
The last argument is a 3-tuple denoting the range of the free
variable. e.g. ``(x, 0, 5)``
Typical usage examples are in the following:
- Plotting a single expression with a single range.
``plot(expr, range, **kwargs)``
- Plotting a single expression with the default range (-10, 10).
``plot(expr, **kwargs)``
- Plotting multiple expressions with a single range.
``plot(expr1, expr2, ..., range, **kwargs)``
- Plotting multiple expressions with multiple ranges.
``plot((expr1, range1), (expr2, range2), ..., **kwargs)``
It is best practice to specify range explicitly because default
range may change in the future if a more advanced default range
detection algorithm is implemented.
show : bool, optional
The default value is set to ``True``. Set show to ``False`` and
the function will not display the plot. The returned instance of
the ``Plot`` class can then be used to save or display the plot
by calling the ``save()`` and ``show()`` methods respectively.
line_color : string, or float, or function, optional
Specifies the color for the plot.
See ``Plot`` to see how to set color for the plots.
Note that by setting ``line_color``, it would be applied simultaneously
to all the series.
title : str, optional
Title of the plot. It is set to the latex representation of
the expression, if the plot has only one expression.
label : str, optional
The label of the expression in the plot. It will be used when
called with ``legend``. Default is the name of the expression.
e.g. ``sin(x)``
xlabel : str or expression, optional
Label for the x-axis.
ylabel : str or expression, optional
Label for the y-axis.
xscale : 'linear' or 'log', optional
Sets the scaling of the x-axis.
yscale : 'linear' or 'log', optional
Sets the scaling of the y-axis.
axis_center : (float, float), optional
Tuple of two floats denoting the coordinates of the center or
{'center', 'auto'}
xlim : (float, float), optional
Denotes the x-axis limits, ``(min, max)```.
ylim : (float, float), optional
Denotes the y-axis limits, ``(min, max)```.
annotations : list, optional
A list of dictionaries specifying the type of annotation
required. The keys in the dictionary should be equivalent
to the arguments of the :external:mod:`matplotlib`'s
:external:meth:`~matplotlib.axes.Axes.annotate` method.
markers : list, optional
A list of dictionaries specifying the type the markers required.
The keys in the dictionary should be equivalent to the arguments
of the :external:mod:`matplotlib`'s :external:func:`~matplotlib.pyplot.plot()` function
along with the marker related keyworded arguments.
rectangles : list, optional
A list of dictionaries specifying the dimensions of the
rectangles to be plotted. The keys in the dictionary should be
equivalent to the arguments of the :external:mod:`matplotlib`'s
:external:class:`~matplotlib.patches.Rectangle` class.
fill : dict, optional
A dictionary specifying the type of color filling required in
the plot. The keys in the dictionary should be equivalent to the
arguments of the :external:mod:`matplotlib`'s
:external:meth:`~matplotlib.axes.Axes.fill_between` method.
adaptive : bool, optional
The default value is set to ``True``. Set adaptive to ``False``
and specify ``n`` if uniform sampling is required.
The plotting uses an adaptive algorithm which samples
recursively to accurately plot. The adaptive algorithm uses a
random point near the midpoint of two points that has to be
further sampled. Hence the same plots can appear slightly
different.
depth : int, optional
Recursion depth of the adaptive algorithm. A depth of value
`n` samples a maximum of `2^{n}` points.
If the ``adaptive`` flag is set to ``False``, this will be
ignored.
n : int, optional
Used when the ``adaptive`` is set to ``False``. The function
is uniformly sampled at ``n`` number of points. If the ``adaptive``
flag is set to ``True``, this will be ignored.
This keyword argument replaces ``nb_of_points``, which should be
considered deprecated.
size : (float, float), optional
A tuple in the form (width, height) in inches to specify the size of
the overall figure. The default value is set to ``None``, meaning
the size will be set by the default backend.
Examples
========
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy import symbols
>>> from sympy.plotting import plot
>>> x = symbols('x')
Single Plot
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> plot(x**2, (x, -5, 5))
Plot object containing:
[0]: cartesian line: x**2 for x over (-5.0, 5.0)
Multiple plots with single range.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> plot(x, x**2, x**3, (x, -5, 5))
Plot object containing:
[0]: cartesian line: x for x over (-5.0, 5.0)
[1]: cartesian line: x**2 for x over (-5.0, 5.0)
[2]: cartesian line: x**3 for x over (-5.0, 5.0)
Multiple plots with different ranges.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> plot((x**2, (x, -6, 6)), (x, (x, -5, 5)))
Plot object containing:
[0]: cartesian line: x**2 for x over (-6.0, 6.0)
[1]: cartesian line: x for x over (-5.0, 5.0)
No adaptive sampling.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> plot(x**2, adaptive=False, n=400)
Plot object containing:
[0]: cartesian line: x**2 for x over (-10.0, 10.0)
See Also
========
Plot, LineOver1DRangeSeries
"""
args = _plot_sympify(args)
plot_expr = _check_arguments(args, 1, 1, **kwargs)
params = kwargs.get("params", None)
free = set()
for p in plot_expr:
if not isinstance(p[1][0], str):
free |= {p[1][0]}
else:
free |= {Symbol(p[1][0])}
if params:
free = free.difference(params.keys())
x = free.pop() if free else Symbol("x")
kwargs.setdefault('xlabel', x)
kwargs.setdefault('ylabel', Function('f')(x))
labels = kwargs.pop("label", [])
rendering_kw = kwargs.pop("rendering_kw", None)
series = _build_line_series(*plot_expr, **kwargs)
_set_labels(series, labels, rendering_kw)
plots = plot_factory(*series, **kwargs)
if show:
plots.show()
return plots
def plot_parametric(*args, show=True, **kwargs):
"""
Plots a 2D parametric curve.
Parameters
==========
args
Common specifications are:
- Plotting a single parametric curve with a range
``plot_parametric((expr_x, expr_y), range)``
- Plotting multiple parametric curves with the same range
``plot_parametric((expr_x, expr_y), ..., range)``
- Plotting multiple parametric curves with different ranges
``plot_parametric((expr_x, expr_y, range), ...)``
``expr_x`` is the expression representing $x$ component of the
parametric function.
``expr_y`` is the expression representing $y$ component of the
parametric function.
``range`` is a 3-tuple denoting the parameter symbol, start and
stop. For example, ``(u, 0, 5)``.
If the range is not specified, then a default range of (-10, 10)
is used.
However, if the arguments are specified as
``(expr_x, expr_y, range), ...``, you must specify the ranges
for each expressions manually.
Default range may change in the future if a more advanced
algorithm is implemented.
adaptive : bool, optional
Specifies whether to use the adaptive sampling or not.
The default value is set to ``True``. Set adaptive to ``False``
and specify ``n`` if uniform sampling is required.
depth : int, optional
The recursion depth of the adaptive algorithm. A depth of
value $n$ samples a maximum of $2^n$ points.
n : int, optional
Used when the ``adaptive`` flag is set to ``False``. Specifies the
number of the points used for the uniform sampling.
This keyword argument replaces ``nb_of_points``, which should be
considered deprecated.
line_color : string, or float, or function, optional
Specifies the color for the plot.
See ``Plot`` to see how to set color for the plots.
Note that by setting ``line_color``, it would be applied simultaneously
to all the series.
label : str, optional
The label of the expression in the plot. It will be used when
called with ``legend``. Default is the name of the expression.
e.g. ``sin(x)``
xlabel : str, optional
Label for the x-axis.
ylabel : str, optional
Label for the y-axis.
xscale : 'linear' or 'log', optional
Sets the scaling of the x-axis.
yscale : 'linear' or 'log', optional
Sets the scaling of the y-axis.
axis_center : (float, float), optional
Tuple of two floats denoting the coordinates of the center or
{'center', 'auto'}
xlim : (float, float), optional
Denotes the x-axis limits, ``(min, max)```.
ylim : (float, float), optional
Denotes the y-axis limits, ``(min, max)```.
size : (float, float), optional
A tuple in the form (width, height) in inches to specify the size of
the overall figure. The default value is set to ``None``, meaning
the size will be set by the default backend.
Examples
========
.. plot::
:context: reset
:format: doctest
:include-source: True
>>> from sympy import plot_parametric, symbols, cos, sin
>>> u = symbols('u')
A parametric plot with a single expression:
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> plot_parametric((cos(u), sin(u)), (u, -5, 5))
Plot object containing:
[0]: parametric cartesian line: (cos(u), sin(u)) for u over (-5.0, 5.0)
A parametric plot with multiple expressions with the same range:
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> plot_parametric((cos(u), sin(u)), (u, cos(u)), (u, -10, 10))
Plot object containing:
[0]: parametric cartesian line: (cos(u), sin(u)) for u over (-10.0, 10.0)
[1]: parametric cartesian line: (u, cos(u)) for u over (-10.0, 10.0)
A parametric plot with multiple expressions with different ranges
for each curve:
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> plot_parametric((cos(u), sin(u), (u, -5, 5)),
... (cos(u), u, (u, -5, 5)))
Plot object containing:
[0]: parametric cartesian line: (cos(u), sin(u)) for u over (-5.0, 5.0)
[1]: parametric cartesian line: (cos(u), u) for u over (-5.0, 5.0)
Notes
=====
The plotting uses an adaptive algorithm which samples recursively to
accurately plot the curve. The adaptive algorithm uses a random point
near the midpoint of two points that has to be further sampled.
Hence, repeating the same plot command can give slightly different
results because of the random sampling.
If there are multiple plots, then the same optional arguments are
applied to all the plots drawn in the same canvas. If you want to
set these options separately, you can index the returned ``Plot``
object and set it.
For example, when you specify ``line_color`` once, it would be
applied simultaneously to both series.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy import pi
>>> expr1 = (u, cos(2*pi*u)/2 + 1/2)
>>> expr2 = (u, sin(2*pi*u)/2 + 1/2)
>>> p = plot_parametric(expr1, expr2, (u, 0, 1), line_color='blue')
If you want to specify the line color for the specific series, you
should index each item and apply the property manually.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> p[0].line_color = 'red'
>>> p.show()
See Also
========
Plot, Parametric2DLineSeries
"""
args = _plot_sympify(args)
plot_expr = _check_arguments(args, 2, 1, **kwargs)
labels = kwargs.pop("label", [])
rendering_kw = kwargs.pop("rendering_kw", None)
series = _create_series(Parametric2DLineSeries, plot_expr, **kwargs)
_set_labels(series, labels, rendering_kw)
plots = plot_factory(*series, **kwargs)
if show:
plots.show()
return plots
def plot3d_parametric_line(*args, show=True, **kwargs):
"""
Plots a 3D parametric line plot.
Usage
=====
Single plot:
``plot3d_parametric_line(expr_x, expr_y, expr_z, range, **kwargs)``
If the range is not specified, then a default range of (-10, 10) is used.
Multiple plots.
``plot3d_parametric_line((expr_x, expr_y, expr_z, range), ..., **kwargs)``
Ranges have to be specified for every expression.
Default range may change in the future if a more advanced default range
detection algorithm is implemented.
Arguments
=========
expr_x : Expression representing the function along x.
expr_y : Expression representing the function along y.
expr_z : Expression representing the function along z.
range : (:class:`~.Symbol`, float, float)
A 3-tuple denoting the range of the parameter variable, e.g., (u, 0, 5).
Keyword Arguments
=================
Arguments for ``Parametric3DLineSeries`` class.
n : int
The range is uniformly sampled at ``n`` number of points.
This keyword argument replaces ``nb_of_points``, which should be
considered deprecated.
Aesthetics:
line_color : string, or float, or function, optional
Specifies the color for the plot.
See ``Plot`` to see how to set color for the plots.
Note that by setting ``line_color``, it would be applied simultaneously
to all the series.
label : str
The label to the plot. It will be used when called with ``legend=True``
to denote the function with the given label in the plot.
If there are multiple plots, then the same series arguments are applied to
all the plots. If you want to set these options separately, you can index
the returned ``Plot`` object and set it.
Arguments for ``Plot`` class.
title : str
Title of the plot.
size : (float, float), optional
A tuple in the form (width, height) in inches to specify the size of
the overall figure. The default value is set to ``None``, meaning
the size will be set by the default backend.
Examples
========
.. plot::
:context: reset
:format: doctest
:include-source: True
>>> from sympy import symbols, cos, sin
>>> from sympy.plotting import plot3d_parametric_line
>>> u = symbols('u')
Single plot.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> plot3d_parametric_line(cos(u), sin(u), u, (u, -5, 5))
Plot object containing:
[0]: 3D parametric cartesian line: (cos(u), sin(u), u) for u over (-5.0, 5.0)
Multiple plots.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> plot3d_parametric_line((cos(u), sin(u), u, (u, -5, 5)),
... (sin(u), u**2, u, (u, -5, 5)))
Plot object containing:
[0]: 3D parametric cartesian line: (cos(u), sin(u), u) for u over (-5.0, 5.0)
[1]: 3D parametric cartesian line: (sin(u), u**2, u) for u over (-5.0, 5.0)
See Also
========
Plot, Parametric3DLineSeries
"""
args = _plot_sympify(args)
plot_expr = _check_arguments(args, 3, 1, **kwargs)
kwargs.setdefault("xlabel", "x")
kwargs.setdefault("ylabel", "y")
kwargs.setdefault("zlabel", "z")
labels = kwargs.pop("label", [])
rendering_kw = kwargs.pop("rendering_kw", None)
series = _create_series(Parametric3DLineSeries, plot_expr, **kwargs)
_set_labels(series, labels, rendering_kw)
plots = plot_factory(*series, **kwargs)
if show:
plots.show()
return plots
def _plot3d_plot_contour_helper(Series, *args, **kwargs):
"""plot3d and plot_contour are structurally identical. Let's reduce
code repetition.
"""
# NOTE: if this import would be at the top-module level, it would trigger
# SymPy's optional-dependencies tests to fail.
from sympy.vector import BaseScalar
args = _plot_sympify(args)
plot_expr = _check_arguments(args, 1, 2, **kwargs)
free_x = set()
free_y = set()
_types = (Symbol, BaseScalar, Indexed, AppliedUndef)
for p in plot_expr:
free_x |= {p[1][0]} if isinstance(p[1][0], _types) else {Symbol(p[1][0])}
free_y |= {p[2][0]} if isinstance(p[2][0], _types) else {Symbol(p[2][0])}
x = free_x.pop() if free_x else Symbol("x")
y = free_y.pop() if free_y else Symbol("y")
kwargs.setdefault("xlabel", x)
kwargs.setdefault("ylabel", y)
kwargs.setdefault("zlabel", Function('f')(x, y))
# if a polar discretization is requested and automatic labelling has ben
# applied, hide the labels on the x-y axis.
if kwargs.get("is_polar", False):
if callable(kwargs["xlabel"]):
kwargs["xlabel"] = ""
if callable(kwargs["ylabel"]):
kwargs["ylabel"] = ""
labels = kwargs.pop("label", [])
rendering_kw = kwargs.pop("rendering_kw", None)
series = _create_series(Series, plot_expr, **kwargs)
_set_labels(series, labels, rendering_kw)
plots = plot_factory(*series, **kwargs)
if kwargs.get("show", True):
plots.show()
return plots
def plot3d(*args, show=True, **kwargs):
"""
Plots a 3D surface plot.
Usage
=====
Single plot
``plot3d(expr, range_x, range_y, **kwargs)``
If the ranges are not specified, then a default range of (-10, 10) is used.
Multiple plot with the same range.
``plot3d(expr1, expr2, range_x, range_y, **kwargs)``
If the ranges are not specified, then a default range of (-10, 10) is used.
Multiple plots with different ranges.
``plot3d((expr1, range_x, range_y), (expr2, range_x, range_y), ..., **kwargs)``
Ranges have to be specified for every expression.
Default range may change in the future if a more advanced default range
detection algorithm is implemented.
Arguments
=========
expr : Expression representing the function along x.
range_x : (:class:`~.Symbol`, float, float)
A 3-tuple denoting the range of the x variable, e.g. (x, 0, 5).
range_y : (:class:`~.Symbol`, float, float)
A 3-tuple denoting the range of the y variable, e.g. (y, 0, 5).
Keyword Arguments
=================
Arguments for ``SurfaceOver2DRangeSeries`` class:
n1 : int
The x range is sampled uniformly at ``n1`` of points.
This keyword argument replaces ``nb_of_points_x``, which should be
considered deprecated.
n2 : int
The y range is sampled uniformly at ``n2`` of points.
This keyword argument replaces ``nb_of_points_y``, which should be
considered deprecated.
Aesthetics:
surface_color : Function which returns a float
Specifies the color for the surface of the plot.
See :class:`~.Plot` for more details.
If there are multiple plots, then the same series arguments are applied to
all the plots. If you want to set these options separately, you can index
the returned ``Plot`` object and set it.
Arguments for ``Plot`` class:
title : str
Title of the plot.
size : (float, float), optional
A tuple in the form (width, height) in inches to specify the size of the
overall figure. The default value is set to ``None``, meaning the size will
be set by the default backend.
Examples
========
.. plot::
:context: reset
:format: doctest
:include-source: True
>>> from sympy import symbols
>>> from sympy.plotting import plot3d
>>> x, y = symbols('x y')
Single plot
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> plot3d(x*y, (x, -5, 5), (y, -5, 5))
Plot object containing:
[0]: cartesian surface: x*y for x over (-5.0, 5.0) and y over (-5.0, 5.0)
Multiple plots with same range
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> plot3d(x*y, -x*y, (x, -5, 5), (y, -5, 5))
Plot object containing:
[0]: cartesian surface: x*y for x over (-5.0, 5.0) and y over (-5.0, 5.0)
[1]: cartesian surface: -x*y for x over (-5.0, 5.0) and y over (-5.0, 5.0)
Multiple plots with different ranges.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> plot3d((x**2 + y**2, (x, -5, 5), (y, -5, 5)),
... (x*y, (x, -3, 3), (y, -3, 3)))
Plot object containing:
[0]: cartesian surface: x**2 + y**2 for x over (-5.0, 5.0) and y over (-5.0, 5.0)
[1]: cartesian surface: x*y for x over (-3.0, 3.0) and y over (-3.0, 3.0)
See Also
========
Plot, SurfaceOver2DRangeSeries
"""
kwargs.setdefault("show", show)
return _plot3d_plot_contour_helper(
SurfaceOver2DRangeSeries, *args, **kwargs)
def plot3d_parametric_surface(*args, show=True, **kwargs):
"""
Plots a 3D parametric surface plot.
Explanation
===========
Single plot.
``plot3d_parametric_surface(expr_x, expr_y, expr_z, range_u, range_v, **kwargs)``
If the ranges is not specified, then a default range of (-10, 10) is used.
Multiple plots.
``plot3d_parametric_surface((expr_x, expr_y, expr_z, range_u, range_v), ..., **kwargs)``
Ranges have to be specified for every expression.
Default range may change in the future if a more advanced default range
detection algorithm is implemented.
Arguments
=========
expr_x : Expression representing the function along ``x``.
expr_y : Expression representing the function along ``y``.
expr_z : Expression representing the function along ``z``.
range_u : (:class:`~.Symbol`, float, float)
A 3-tuple denoting the range of the u variable, e.g. (u, 0, 5).
range_v : (:class:`~.Symbol`, float, float)
A 3-tuple denoting the range of the v variable, e.g. (v, 0, 5).
Keyword Arguments
=================
Arguments for ``ParametricSurfaceSeries`` class:
n1 : int
The ``u`` range is sampled uniformly at ``n1`` of points.
This keyword argument replaces ``nb_of_points_u``, which should be
considered deprecated.
n2 : int
The ``v`` range is sampled uniformly at ``n2`` of points.
This keyword argument replaces ``nb_of_points_v``, which should be
considered deprecated.
Aesthetics:
surface_color : Function which returns a float
Specifies the color for the surface of the plot. See
:class:`~Plot` for more details.
If there are multiple plots, then the same series arguments are applied for
all the plots. If you want to set these options separately, you can index
the returned ``Plot`` object and set it.
Arguments for ``Plot`` class:
title : str
Title of the plot.
size : (float, float), optional
A tuple in the form (width, height) in inches to specify the size of the
overall figure. The default value is set to ``None``, meaning the size will
be set by the default backend.
Examples
========
.. plot::
:context: reset
:format: doctest
:include-source: True
>>> from sympy import symbols, cos, sin
>>> from sympy.plotting import plot3d_parametric_surface
>>> u, v = symbols('u v')
Single plot.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> plot3d_parametric_surface(cos(u + v), sin(u - v), u - v,
... (u, -5, 5), (v, -5, 5))
Plot object containing:
[0]: parametric cartesian surface: (cos(u + v), sin(u - v), u - v) for u over (-5.0, 5.0) and v over (-5.0, 5.0)
See Also
========
Plot, ParametricSurfaceSeries
"""
args = _plot_sympify(args)
plot_expr = _check_arguments(args, 3, 2, **kwargs)
kwargs.setdefault("xlabel", "x")
kwargs.setdefault("ylabel", "y")
kwargs.setdefault("zlabel", "z")
labels = kwargs.pop("label", [])
rendering_kw = kwargs.pop("rendering_kw", None)
series = _create_series(ParametricSurfaceSeries, plot_expr, **kwargs)
_set_labels(series, labels, rendering_kw)
plots = plot_factory(*series, **kwargs)
if show:
plots.show()
return plots
def plot_contour(*args, show=True, **kwargs):
"""
Draws contour plot of a function
Usage
=====
Single plot
``plot_contour(expr, range_x, range_y, **kwargs)``
If the ranges are not specified, then a default range of (-10, 10) is used.
Multiple plot with the same range.
``plot_contour(expr1, expr2, range_x, range_y, **kwargs)``
If the ranges are not specified, then a default range of (-10, 10) is used.
Multiple plots with different ranges.
``plot_contour((expr1, range_x, range_y), (expr2, range_x, range_y), ..., **kwargs)``
Ranges have to be specified for every expression.
Default range may change in the future if a more advanced default range
detection algorithm is implemented.
Arguments
=========
expr : Expression representing the function along x.
range_x : (:class:`Symbol`, float, float)
A 3-tuple denoting the range of the x variable, e.g. (x, 0, 5).
range_y : (:class:`Symbol`, float, float)
A 3-tuple denoting the range of the y variable, e.g. (y, 0, 5).
Keyword Arguments
=================
Arguments for ``ContourSeries`` class:
n1 : int
The x range is sampled uniformly at ``n1`` of points.
This keyword argument replaces ``nb_of_points_x``, which should be
considered deprecated.
n2 : int
The y range is sampled uniformly at ``n2`` of points.
This keyword argument replaces ``nb_of_points_y``, which should be
considered deprecated.
Aesthetics:
surface_color : Function which returns a float
Specifies the color for the surface of the plot. See
:class:`sympy.plotting.Plot` for more details.
If there are multiple plots, then the same series arguments are applied to
all the plots. If you want to set these options separately, you can index
the returned ``Plot`` object and set it.
Arguments for ``Plot`` class:
title : str
Title of the plot.
size : (float, float), optional
A tuple in the form (width, height) in inches to specify the size of
the overall figure. The default value is set to ``None``, meaning
the size will be set by the default backend.
See Also
========
Plot, ContourSeries
"""
kwargs.setdefault("show", show)
return _plot3d_plot_contour_helper(ContourSeries, *args, **kwargs)
def check_arguments(args, expr_len, nb_of_free_symbols):
"""
Checks the arguments and converts into tuples of the
form (exprs, ranges).
Examples
========
.. plot::
:context: reset
:format: doctest
:include-source: True
>>> from sympy import cos, sin, symbols
>>> from sympy.plotting.plot import check_arguments
>>> x = symbols('x')
>>> check_arguments([cos(x), sin(x)], 2, 1)
[(cos(x), sin(x), (x, -10, 10))]
>>> check_arguments([x, x**2], 1, 1)
[(x, (x, -10, 10)), (x**2, (x, -10, 10))]
"""
if not args:
return []
if expr_len > 1 and isinstance(args[0], Expr):
# Multiple expressions same range.
# The arguments are tuples when the expression length is
# greater than 1.
if len(args) < expr_len:
raise ValueError("len(args) should not be less than expr_len")
for i in range(len(args)):
if isinstance(args[i], Tuple):
break
else:
i = len(args) + 1
exprs = Tuple(*args[:i])
free_symbols = list(set().union(*[e.free_symbols for e in exprs]))
if len(args) == expr_len + nb_of_free_symbols:
#Ranges given
plots = [exprs + Tuple(*args[expr_len:])]
else:
default_range = Tuple(-10, 10)
ranges = []
for symbol in free_symbols:
ranges.append(Tuple(symbol) + default_range)
for i in range(len(free_symbols) - nb_of_free_symbols):
ranges.append(Tuple(Dummy()) + default_range)
plots = [exprs + Tuple(*ranges)]
return plots
if isinstance(args[0], Expr) or (isinstance(args[0], Tuple) and
len(args[0]) == expr_len and
expr_len != 3):
# Cannot handle expressions with number of expression = 3. It is
# not possible to differentiate between expressions and ranges.
#Series of plots with same range
for i in range(len(args)):
if isinstance(args[i], Tuple) and len(args[i]) != expr_len:
break
if not isinstance(args[i], Tuple):
args[i] = Tuple(args[i])
else:
i = len(args) + 1
exprs = args[:i]
assert all(isinstance(e, Expr) for expr in exprs for e in expr)
free_symbols = list(set().union(*[e.free_symbols for expr in exprs
for e in expr]))
if len(free_symbols) > nb_of_free_symbols:
raise ValueError("The number of free_symbols in the expression "
"is greater than %d" % nb_of_free_symbols)
if len(args) == i + nb_of_free_symbols and isinstance(args[i], Tuple):
ranges = Tuple(*list(args[
i:i + nb_of_free_symbols]))
plots = [expr + ranges for expr in exprs]
return plots
else:
# Use default ranges.
default_range = Tuple(-10, 10)
ranges = []
for symbol in free_symbols:
ranges.append(Tuple(symbol) + default_range)
for i in range(nb_of_free_symbols - len(free_symbols)):
ranges.append(Tuple(Dummy()) + default_range)
ranges = Tuple(*ranges)
plots = [expr + ranges for expr in exprs]
return plots
elif isinstance(args[0], Tuple) and len(args[0]) == expr_len + nb_of_free_symbols:
# Multiple plots with different ranges.
for arg in args:
for i in range(expr_len):
if not isinstance(arg[i], Expr):
raise ValueError("Expected an expression, given %s" %
str(arg[i]))
for i in range(nb_of_free_symbols):
if not len(arg[i + expr_len]) == 3:
raise ValueError("The ranges should be a tuple of "
"length 3, got %s" % str(arg[i + expr_len]))
return args
PK ]ZZZ�?%� � sympy/plotting/plot_implicit.py"""Implicit plotting module for SymPy.
Explanation
===========
The module implements a data series called ImplicitSeries which is used by
``Plot`` class to plot implicit plots for different backends. The module,
by default, implements plotting using interval arithmetic. It switches to a
fall back algorithm if the expression cannot be plotted using interval arithmetic.
It is also possible to specify to use the fall back algorithm for all plots.
Boolean combinations of expressions cannot be plotted by the fall back
algorithm.
See Also
========
sympy.plotting.plot
References
==========
.. [1] Jeffrey Allen Tupper. Reliable Two-Dimensional Graphing Methods for
Mathematical Formulae with Two Free Variables.
.. [2] Jeffrey Allen Tupper. Graphing Equations with Generalized Interval
Arithmetic. Master's thesis. University of Toronto, 1996
"""
from sympy.core.containers import Tuple
from sympy.core.symbol import (Dummy, Symbol)
from sympy.polys.polyutils import _sort_gens
from sympy.plotting.series import ImplicitSeries, _set_discretization_points
from sympy.plotting.plot import plot_factory
from sympy.utilities.decorator import doctest_depends_on
from sympy.utilities.iterables import flatten
__doctest_requires__ = {'plot_implicit': ['matplotlib']}
@doctest_depends_on(modules=('matplotlib',))
def plot_implicit(expr, x_var=None, y_var=None, adaptive=True, depth=0,
n=300, line_color="blue", show=True, **kwargs):
"""A plot function to plot implicit equations / inequalities.
Arguments
=========
- expr : The equation / inequality that is to be plotted.
- x_var (optional) : symbol to plot on x-axis or tuple giving symbol
and range as ``(symbol, xmin, xmax)``
- y_var (optional) : symbol to plot on y-axis or tuple giving symbol
and range as ``(symbol, ymin, ymax)``
If neither ``x_var`` nor ``y_var`` are given then the free symbols in the
expression will be assigned in the order they are sorted.
The following keyword arguments can also be used:
- ``adaptive`` Boolean. The default value is set to True. It has to be
set to False if you want to use a mesh grid.
- ``depth`` integer. The depth of recursion for adaptive mesh grid.
Default value is 0. Takes value in the range (0, 4).
- ``n`` integer. The number of points if adaptive mesh grid is not
used. Default value is 300. This keyword argument replaces ``points``,
which should be considered deprecated.
- ``show`` Boolean. Default value is True. If set to False, the plot will
not be shown. See ``Plot`` for further information.
- ``title`` string. The title for the plot.
- ``xlabel`` string. The label for the x-axis
- ``ylabel`` string. The label for the y-axis
Aesthetics options:
- ``line_color``: float or string. Specifies the color for the plot.
See ``Plot`` to see how to set color for the plots.
Default value is "Blue"
plot_implicit, by default, uses interval arithmetic to plot functions. If
the expression cannot be plotted using interval arithmetic, it defaults to
a generating a contour using a mesh grid of fixed number of points. By
setting adaptive to False, you can force plot_implicit to use the mesh
grid. The mesh grid method can be effective when adaptive plotting using
interval arithmetic, fails to plot with small line width.
Examples
========
Plot expressions:
.. plot::
:context: reset
:format: doctest
:include-source: True
>>> from sympy import plot_implicit, symbols, Eq, And
>>> x, y = symbols('x y')
Without any ranges for the symbols in the expression:
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> p1 = plot_implicit(Eq(x**2 + y**2, 5))
With the range for the symbols:
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> p2 = plot_implicit(
... Eq(x**2 + y**2, 3), (x, -3, 3), (y, -3, 3))
With depth of recursion as argument:
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> p3 = plot_implicit(
... Eq(x**2 + y**2, 5), (x, -4, 4), (y, -4, 4), depth = 2)
Using mesh grid and not using adaptive meshing:
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> p4 = plot_implicit(
... Eq(x**2 + y**2, 5), (x, -5, 5), (y, -2, 2),
... adaptive=False)
Using mesh grid without using adaptive meshing with number of points
specified:
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> p5 = plot_implicit(
... Eq(x**2 + y**2, 5), (x, -5, 5), (y, -2, 2),
... adaptive=False, n=400)
Plotting regions:
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> p6 = plot_implicit(y > x**2)
Plotting Using boolean conjunctions:
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> p7 = plot_implicit(And(y > x, y > -x))
When plotting an expression with a single variable (y - 1, for example),
specify the x or the y variable explicitly:
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> p8 = plot_implicit(y - 1, y_var=y)
>>> p9 = plot_implicit(x - 1, x_var=x)
"""
xyvar = [i for i in (x_var, y_var) if i is not None]
free_symbols = expr.free_symbols
range_symbols = Tuple(*flatten(xyvar)).free_symbols
undeclared = free_symbols - range_symbols
if len(free_symbols & range_symbols) > 2:
raise NotImplementedError("Implicit plotting is not implemented for "
"more than 2 variables")
#Create default ranges if the range is not provided.
default_range = Tuple(-5, 5)
def _range_tuple(s):
if isinstance(s, Symbol):
return Tuple(s) + default_range
if len(s) == 3:
return Tuple(*s)
raise ValueError('symbol or `(symbol, min, max)` expected but got %s' % s)
if len(xyvar) == 0:
xyvar = list(_sort_gens(free_symbols))
var_start_end_x = _range_tuple(xyvar[0])
x = var_start_end_x[0]
if len(xyvar) != 2:
if x in undeclared or not undeclared:
xyvar.append(Dummy('f(%s)' % x.name))
else:
xyvar.append(undeclared.pop())
var_start_end_y = _range_tuple(xyvar[1])
kwargs = _set_discretization_points(kwargs, ImplicitSeries)
series_argument = ImplicitSeries(
expr, var_start_end_x, var_start_end_y,
adaptive=adaptive, depth=depth,
n=n, line_color=line_color)
#set the x and y limits
kwargs['xlim'] = tuple(float(x) for x in var_start_end_x[1:])
kwargs['ylim'] = tuple(float(y) for y in var_start_end_y[1:])
# set the x and y labels
kwargs.setdefault('xlabel', var_start_end_x[0])
kwargs.setdefault('ylabel', var_start_end_y[0])
p = plot_factory(series_argument, **kwargs)
if show:
p.show()
return p
PK ]ZZZ/��'� � sympy/plotting/plotgrid.py
from sympy.external import import_module
import sympy.plotting.backends.base_backend as base_backend
# N.B.
# When changing the minimum module version for matplotlib, please change
# the same in the `SymPyDocTestFinder`` in `sympy/testing/runtests.py`
__doctest_requires__ = {
("PlotGrid",): ["matplotlib"],
}
class PlotGrid:
"""This class helps to plot subplots from already created SymPy plots
in a single figure.
Examples
========
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy import symbols
>>> from sympy.plotting import plot, plot3d, PlotGrid
>>> x, y = symbols('x, y')
>>> p1 = plot(x, x**2, x**3, (x, -5, 5))
>>> p2 = plot((x**2, (x, -6, 6)), (x, (x, -5, 5)))
>>> p3 = plot(x**3, (x, -5, 5))
>>> p4 = plot3d(x*y, (x, -5, 5), (y, -5, 5))
Plotting vertically in a single line:
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> PlotGrid(2, 1, p1, p2)
PlotGrid object containing:
Plot[0]:Plot object containing:
[0]: cartesian line: x for x over (-5.0, 5.0)
[1]: cartesian line: x**2 for x over (-5.0, 5.0)
[2]: cartesian line: x**3 for x over (-5.0, 5.0)
Plot[1]:Plot object containing:
[0]: cartesian line: x**2 for x over (-6.0, 6.0)
[1]: cartesian line: x for x over (-5.0, 5.0)
Plotting horizontally in a single line:
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> PlotGrid(1, 3, p2, p3, p4)
PlotGrid object containing:
Plot[0]:Plot object containing:
[0]: cartesian line: x**2 for x over (-6.0, 6.0)
[1]: cartesian line: x for x over (-5.0, 5.0)
Plot[1]:Plot object containing:
[0]: cartesian line: x**3 for x over (-5.0, 5.0)
Plot[2]:Plot object containing:
[0]: cartesian surface: x*y for x over (-5.0, 5.0) and y over (-5.0, 5.0)
Plotting in a grid form:
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> PlotGrid(2, 2, p1, p2, p3, p4)
PlotGrid object containing:
Plot[0]:Plot object containing:
[0]: cartesian line: x for x over (-5.0, 5.0)
[1]: cartesian line: x**2 for x over (-5.0, 5.0)
[2]: cartesian line: x**3 for x over (-5.0, 5.0)
Plot[1]:Plot object containing:
[0]: cartesian line: x**2 for x over (-6.0, 6.0)
[1]: cartesian line: x for x over (-5.0, 5.0)
Plot[2]:Plot object containing:
[0]: cartesian line: x**3 for x over (-5.0, 5.0)
Plot[3]:Plot object containing:
[0]: cartesian surface: x*y for x over (-5.0, 5.0) and y over (-5.0, 5.0)
"""
def __init__(self, nrows, ncolumns, *args, show=True, size=None, **kwargs):
"""
Parameters
==========
nrows :
The number of rows that should be in the grid of the
required subplot.
ncolumns :
The number of columns that should be in the grid
of the required subplot.
nrows and ncolumns together define the required grid.
Arguments
=========
A list of predefined plot objects entered in a row-wise sequence
i.e. plot objects which are to be in the top row of the required
grid are written first, then the second row objects and so on
Keyword arguments
=================
show : Boolean
The default value is set to ``True``. Set show to ``False`` and
the function will not display the subplot. The returned instance
of the ``PlotGrid`` class can then be used to save or display the
plot by calling the ``save()`` and ``show()`` methods
respectively.
size : (float, float), optional
A tuple in the form (width, height) in inches to specify the size of
the overall figure. The default value is set to ``None``, meaning
the size will be set by the default backend.
"""
self.matplotlib = import_module('matplotlib',
import_kwargs={'fromlist': ['pyplot', 'cm', 'collections']},
min_module_version='1.1.0', catch=(RuntimeError,))
self.nrows = nrows
self.ncolumns = ncolumns
self._series = []
self._fig = None
self.args = args
for arg in args:
self._series.append(arg._series)
self.size = size
if show and self.matplotlib:
self.show()
def _create_figure(self):
gs = self.matplotlib.gridspec.GridSpec(self.nrows, self.ncolumns)
mapping = {}
c = 0
for i in range(self.nrows):
for j in range(self.ncolumns):
if c < len(self.args):
mapping[gs[i, j]] = self.args[c]
c += 1
kw = {} if not self.size else {"figsize": self.size}
self._fig = self.matplotlib.pyplot.figure(**kw)
for spec, p in mapping.items():
kw = ({"projection": "3d"} if (len(p._series) > 0 and
p._series[0].is_3D) else {})
cur_ax = self._fig.add_subplot(spec, **kw)
p._plotgrid_fig = self._fig
p._plotgrid_ax = cur_ax
p.process_series()
@property
def fig(self):
if not self._fig:
self._create_figure()
return self._fig
@property
def _backend(self):
return self
def close(self):
self.matplotlib.pyplot.close(self.fig)
def show(self):
if base_backend._show:
self.fig.tight_layout()
self.matplotlib.pyplot.show()
else:
self.close()
def save(self, path):
self.fig.savefig(path)
def __str__(self):
plot_strs = [('Plot[%d]:' % i) + str(plot)
for i, plot in enumerate(self.args)]
return 'PlotGrid object containing:\n' + '\n'.join(plot_strs)
PK ]ZZZ��>�3y 3y sympy/plotting/series.py### The base class for all series
from collections.abc import Callable
from sympy.calculus.util import continuous_domain
from sympy.concrete import Sum, Product
from sympy.core.containers import Tuple
from sympy.core.expr import Expr
from sympy.core.function import arity
from sympy.core.sorting import default_sort_key
from sympy.core.symbol import Symbol
from sympy.functions import atan2, zeta, frac, ceiling, floor, im
from sympy.core.relational import (Equality, GreaterThan,
LessThan, Relational, Ne)
from sympy.core.sympify import sympify
from sympy.external import import_module
from sympy.logic.boolalg import BooleanFunction
from sympy.plotting.utils import _get_free_symbols, extract_solution
from sympy.printing.latex import latex
from sympy.printing.pycode import PythonCodePrinter
from sympy.printing.precedence import precedence
from sympy.sets.sets import Set, Interval, Union
from sympy.simplify.simplify import nsimplify
from sympy.utilities.exceptions import sympy_deprecation_warning
from sympy.utilities.lambdify import lambdify
from .intervalmath import interval
import warnings
class IntervalMathPrinter(PythonCodePrinter):
"""A printer to be used inside `plot_implicit` when `adaptive=True`,
in which case the interval arithmetic module is going to be used, which
requires the following edits.
"""
def _print_And(self, expr):
PREC = precedence(expr)
return " & ".join(self.parenthesize(a, PREC)
for a in sorted(expr.args, key=default_sort_key))
def _print_Or(self, expr):
PREC = precedence(expr)
return " | ".join(self.parenthesize(a, PREC)
for a in sorted(expr.args, key=default_sort_key))
def _uniform_eval(f1, f2, *args, modules=None,
force_real_eval=False, has_sum=False):
"""
Note: this is an experimental function, as such it is prone to changes.
Please, do not use it in your code.
"""
np = import_module('numpy')
def wrapper_func(func, *args):
try:
return complex(func(*args))
except (ZeroDivisionError, OverflowError):
return complex(np.nan, np.nan)
# NOTE: np.vectorize is much slower than numpy vectorized operations.
# However, this modules must be able to evaluate functions also with
# mpmath or sympy.
wrapper_func = np.vectorize(wrapper_func, otypes=[complex])
def _eval_with_sympy(err=None):
if f2 is None:
msg = "Impossible to evaluate the provided numerical function"
if err is None:
msg += "."
else:
msg += "because the following exception was raised:\n"
"{}: {}".format(type(err).__name__, err)
raise RuntimeError(msg)
if err:
warnings.warn(
"The evaluation with %s failed.\n" % (
"NumPy/SciPy" if not modules else modules) +
"{}: {}\n".format(type(err).__name__, err) +
"Trying to evaluate the expression with Sympy, but it might "
"be a slow operation."
)
return wrapper_func(f2, *args)
if modules == "sympy":
return _eval_with_sympy()
try:
return wrapper_func(f1, *args)
except Exception as err:
return _eval_with_sympy(err)
def _adaptive_eval(f, x):
"""Evaluate f(x) with an adaptive algorithm. Post-process the result.
If a symbolic expression is evaluated with SymPy, it might returns
another symbolic expression, containing additions, ...
Force evaluation to a float.
Parameters
==========
f : callable
x : float
"""
np = import_module('numpy')
y = f(x)
if isinstance(y, Expr) and (not y.is_Number):
y = y.evalf()
y = complex(y)
if y.imag > 1e-08:
return np.nan
return y.real
def _get_wrapper_for_expr(ret):
wrapper = "%s"
if ret == "real":
wrapper = "re(%s)"
elif ret == "imag":
wrapper = "im(%s)"
elif ret == "abs":
wrapper = "abs(%s)"
elif ret == "arg":
wrapper = "arg(%s)"
return wrapper
class BaseSeries:
"""Base class for the data objects containing stuff to be plotted.
Notes
=====
The backend should check if it supports the data series that is given.
(e.g. TextBackend supports only LineOver1DRangeSeries).
It is the backend responsibility to know how to use the class of
data series that is given.
Some data series classes are grouped (using a class attribute like is_2Dline)
according to the api they present (based only on convention). The backend is
not obliged to use that api (e.g. LineOver1DRangeSeries belongs to the
is_2Dline group and presents the get_points method, but the
TextBackend does not use the get_points method).
BaseSeries
"""
# Some flags follow. The rationale for using flags instead of checking base
# classes is that setting multiple flags is simpler than multiple
# inheritance.
is_2Dline = False
# Some of the backends expect:
# - get_points returning 1D np.arrays list_x, list_y
# - get_color_array returning 1D np.array (done in Line2DBaseSeries)
# with the colors calculated at the points from get_points
is_3Dline = False
# Some of the backends expect:
# - get_points returning 1D np.arrays list_x, list_y, list_y
# - get_color_array returning 1D np.array (done in Line2DBaseSeries)
# with the colors calculated at the points from get_points
is_3Dsurface = False
# Some of the backends expect:
# - get_meshes returning mesh_x, mesh_y, mesh_z (2D np.arrays)
# - get_points an alias for get_meshes
is_contour = False
# Some of the backends expect:
# - get_meshes returning mesh_x, mesh_y, mesh_z (2D np.arrays)
# - get_points an alias for get_meshes
is_implicit = False
# Some of the backends expect:
# - get_meshes returning mesh_x (1D array), mesh_y(1D array,
# mesh_z (2D np.arrays)
# - get_points an alias for get_meshes
# Different from is_contour as the colormap in backend will be
# different
is_interactive = False
# An interactive series can update its data.
is_parametric = False
# The calculation of aesthetics expects:
# - get_parameter_points returning one or two np.arrays (1D or 2D)
# used for calculation aesthetics
is_generic = False
# Represent generic user-provided numerical data
is_vector = False
is_2Dvector = False
is_3Dvector = False
# Represents a 2D or 3D vector data series
_N = 100
# default number of discretization points for uniform sampling. Each
# subclass can set its number.
def __init__(self, *args, **kwargs):
kwargs = _set_discretization_points(kwargs.copy(), type(self))
# discretize the domain using only integer numbers
self.only_integers = kwargs.get("only_integers", False)
# represents the evaluation modules to be used by lambdify
self.modules = kwargs.get("modules", None)
# plot functions might create data series that might not be useful to
# be shown on the legend, for example wireframe lines on 3D plots.
self.show_in_legend = kwargs.get("show_in_legend", True)
# line and surface series can show data with a colormap, hence a
# colorbar is essential to understand the data. However, sometime it
# is useful to hide it on series-by-series base. The following keyword
# controls wheter the series should show a colorbar or not.
self.colorbar = kwargs.get("colorbar", True)
# Some series might use a colormap as default coloring. Setting this
# attribute to False will inform the backends to use solid color.
self.use_cm = kwargs.get("use_cm", False)
# If True, the backend will attempt to render it on a polar-projection
# axis, or using a polar discretization if a 3D plot is requested
self.is_polar = kwargs.get("is_polar", kwargs.get("polar", False))
# If True, the rendering will use points, not lines.
self.is_point = kwargs.get("is_point", kwargs.get("point", False))
# some backend is able to render latex, other needs standard text
self._label = self._latex_label = ""
self._ranges = []
self._n = [
int(kwargs.get("n1", self._N)),
int(kwargs.get("n2", self._N)),
int(kwargs.get("n3", self._N))
]
self._scales = [
kwargs.get("xscale", "linear"),
kwargs.get("yscale", "linear"),
kwargs.get("zscale", "linear")
]
# enable interactive widget plots
self._params = kwargs.get("params", {})
if not isinstance(self._params, dict):
raise TypeError("`params` must be a dictionary mapping symbols "
"to numeric values.")
if len(self._params) > 0:
self.is_interactive = True
# contains keyword arguments that will be passed to the rendering
# function of the chosen plotting library
self.rendering_kw = kwargs.get("rendering_kw", {})
# numerical transformation functions to be applied to the output data:
# x, y, z (coordinates), p (parameter on parametric plots)
self._tx = kwargs.get("tx", None)
self._ty = kwargs.get("ty", None)
self._tz = kwargs.get("tz", None)
self._tp = kwargs.get("tp", None)
if not all(callable(t) or (t is None) for t in
[self._tx, self._ty, self._tz, self._tp]):
raise TypeError("`tx`, `ty`, `tz`, `tp` must be functions.")
# list of numerical functions representing the expressions to evaluate
self._functions = []
# signature for the numerical functions
self._signature = []
# some expressions don't like to be evaluated over complex data.
# if that's the case, set this to True
self._force_real_eval = kwargs.get("force_real_eval", None)
# this attribute will eventually contain a dictionary with the
# discretized ranges
self._discretized_domain = None
# wheter the series contains any interactive range, which is a range
# where the minimum and maximum values can be changed with an
# interactive widget
self._interactive_ranges = False
# NOTE: consider a generic summation, for example:
# s = Sum(cos(pi * x), (x, 1, y))
# This gets lambdified to something:
# sum(cos(pi*x) for x in range(1, y+1))
# Hence, y needs to be an integer, otherwise it raises:
# TypeError: 'complex' object cannot be interpreted as an integer
# This list will contains symbols that are upper bound to summations
# or products
self._needs_to_be_int = []
# a color function will be responsible to set the line/surface color
# according to some logic. Each data series will et an appropriate
# default value.
self.color_func = None
# NOTE: color_func usually receives numerical functions that are going
# to be evaluated over the coordinates of the computed points (or the
# discretized meshes).
# However, if an expression is given to color_func, then it will be
# lambdified with symbols in self._signature, and it will be evaluated
# with the same data used to evaluate the plotted expression.
self._eval_color_func_with_signature = False
def _block_lambda_functions(self, *exprs):
"""Some data series can be used to plot numerical functions, others
cannot. Execute this method inside the `__init__` to prevent the
processing of numerical functions.
"""
if any(callable(e) for e in exprs):
raise TypeError(type(self).__name__ + " requires a symbolic "
"expression.")
def _check_fs(self):
""" Checks if there are enogh parameters and free symbols.
"""
exprs, ranges = self.expr, self.ranges
params, label = self.params, self.label
exprs = exprs if hasattr(exprs, "__iter__") else [exprs]
if any(callable(e) for e in exprs):
return
# from the expression's free symbols, remove the ones used in
# the parameters and the ranges
fs = _get_free_symbols(exprs)
fs = fs.difference(params.keys())
if ranges is not None:
fs = fs.difference([r[0] for r in ranges])
if len(fs) > 0:
raise ValueError(
"Incompatible expression and parameters.\n"
+ "Expression: {}\n".format(
(exprs, ranges, label) if ranges is not None else (exprs, label))
+ "params: {}\n".format(params)
+ "Specify what these symbols represent: {}\n".format(fs)
+ "Are they ranges or parameters?"
)
# verify that all symbols are known (they either represent plotting
# ranges or parameters)
range_symbols = [r[0] for r in ranges]
for r in ranges:
fs = set().union(*[e.free_symbols for e in r[1:]])
if any(t in fs for t in range_symbols):
# ranges can't depend on each other, for example this are
# not allowed:
# (x, 0, y), (y, 0, 3)
# (x, 0, y), (y, x + 2, 3)
raise ValueError("Range symbols can't be included into "
"minimum and maximum of a range. "
"Received range: %s" % str(r))
if len(fs) > 0:
self._interactive_ranges = True
remaining_fs = fs.difference(params.keys())
if len(remaining_fs) > 0:
raise ValueError(
"Unkown symbols found in plotting range: %s. " % (r,) +
"Are the following parameters? %s" % remaining_fs)
def _create_lambda_func(self):
"""Create the lambda functions to be used by the uniform meshing
strategy.
Notes
=====
The old sympy.plotting used experimental_lambdify. It created one
lambda function each time an evaluation was requested. If that failed,
it went on to create a different lambda function and evaluated it,
and so on.
This new module changes strategy: it creates right away the default
lambda function as well as the backup one. The reason is that the
series could be interactive, hence the numerical function will be
evaluated multiple times. So, let's create the functions just once.
This approach works fine for the majority of cases, in which the
symbolic expression is relatively short, hence the lambdification
is fast. If the expression is very long, this approach takes twice
the time to create the lambda functions. Be aware of that!
"""
exprs = self.expr if hasattr(self.expr, "__iter__") else [self.expr]
if not any(callable(e) for e in exprs):
fs = _get_free_symbols(exprs)
self._signature = sorted(fs, key=lambda t: t.name)
# Generate a list of lambda functions, two for each expression:
# 1. the default one.
# 2. the backup one, in case of failures with the default one.
self._functions = []
for e in exprs:
# TODO: set cse=True once this issue is solved:
# https://github.com/sympy/sympy/issues/24246
self._functions.append([
lambdify(self._signature, e, modules=self.modules),
lambdify(self._signature, e, modules="sympy", dummify=True),
])
else:
self._signature = sorted([r[0] for r in self.ranges], key=lambda t: t.name)
self._functions = [(e, None) for e in exprs]
# deal with symbolic color_func
if isinstance(self.color_func, Expr):
self.color_func = lambdify(self._signature, self.color_func)
self._eval_color_func_with_signature = True
def _update_range_value(self, t):
"""If the value of a plotting range is a symbolic expression,
substitute the parameters in order to get a numerical value.
"""
if not self._interactive_ranges:
return complex(t)
return complex(t.subs(self.params))
def _create_discretized_domain(self):
"""Discretize the ranges for uniform meshing strategy.
"""
# NOTE: the goal is to create a dictionary stored in
# self._discretized_domain, mapping symbols to a numpy array
# representing the discretization
discr_symbols = []
discretizations = []
# create a 1D discretization
for i, r in enumerate(self.ranges):
discr_symbols.append(r[0])
c_start = self._update_range_value(r[1])
c_end = self._update_range_value(r[2])
start = c_start.real if c_start.imag == c_end.imag == 0 else c_start
end = c_end.real if c_start.imag == c_end.imag == 0 else c_end
needs_integer_discr = self.only_integers or (r[0] in self._needs_to_be_int)
d = BaseSeries._discretize(start, end, self.n[i],
scale=self.scales[i],
only_integers=needs_integer_discr)
if ((not self._force_real_eval) and (not needs_integer_discr) and
(d.dtype != "complex")):
d = d + 1j * c_start.imag
if needs_integer_discr:
d = d.astype(int)
discretizations.append(d)
# create 2D or 3D
self._create_discretized_domain_helper(discr_symbols, discretizations)
def _create_discretized_domain_helper(self, discr_symbols, discretizations):
"""Create 2D or 3D discretized grids.
Subclasses should override this method in order to implement a
different behaviour.
"""
np = import_module('numpy')
# discretization suitable for 2D line plots, 3D surface plots,
# contours plots, vector plots
# NOTE: why indexing='ij'? Because it produces consistent results with
# np.mgrid. This is important as Mayavi requires this indexing
# to correctly compute 3D streamlines. While VTK is able to compute
# streamlines regardless of the indexing, with indexing='xy' it
# produces "strange" results with "voids" into the
# discretization volume. indexing='ij' solves the problem.
# Also note that matplotlib 2D streamlines requires indexing='xy'.
indexing = "xy"
if self.is_3Dvector or (self.is_3Dsurface and self.is_implicit):
indexing = "ij"
meshes = np.meshgrid(*discretizations, indexing=indexing)
self._discretized_domain = dict(zip(discr_symbols, meshes))
def _evaluate(self, cast_to_real=True):
"""Evaluation of the symbolic expression (or expressions) with the
uniform meshing strategy, based on current values of the parameters.
"""
np = import_module('numpy')
# create lambda functions
if not self._functions:
self._create_lambda_func()
# create (or update) the discretized domain
if (not self._discretized_domain) or self._interactive_ranges:
self._create_discretized_domain()
# ensure that discretized domains are returned with the proper order
discr = [self._discretized_domain[s[0]] for s in self.ranges]
args = self._aggregate_args()
results = []
for f in self._functions:
r = _uniform_eval(*f, *args)
# the evaluation might produce an int/float. Need this correction.
r = self._correct_shape(np.array(r), discr[0])
# sometime the evaluation is performed over arrays of type object.
# hence, `result` might be of type object, which don't work well
# with numpy real and imag functions.
r = r.astype(complex)
results.append(r)
if cast_to_real:
discr = [np.real(d.astype(complex)) for d in discr]
return [*discr, *results]
def _aggregate_args(self):
"""Create a list of arguments to be passed to the lambda function,
sorted accoring to self._signature.
"""
args = []
for s in self._signature:
if s in self._params.keys():
args.append(
int(self._params[s]) if s in self._needs_to_be_int else
self._params[s] if self._force_real_eval
else complex(self._params[s]))
else:
args.append(self._discretized_domain[s])
return args
@property
def expr(self):
"""Return the expression (or expressions) of the series."""
return self._expr
@expr.setter
def expr(self, e):
"""Set the expression (or expressions) of the series."""
is_iter = hasattr(e, "__iter__")
is_callable = callable(e) if not is_iter else any(callable(t) for t in e)
if is_callable:
self._expr = e
else:
self._expr = sympify(e) if not is_iter else Tuple(*e)
# look for the upper bound of summations and products
s = set()
for e in self._expr.atoms(Sum, Product):
for a in e.args[1:]:
if isinstance(a[-1], Symbol):
s.add(a[-1])
self._needs_to_be_int = list(s)
# list of sympy functions that when lambdified, the corresponding
# numpy functions don't like complex-type arguments
pf = [ceiling, floor, atan2, frac, zeta]
if self._force_real_eval is not True:
check_res = [self._expr.has(f) for f in pf]
self._force_real_eval = any(check_res)
if self._force_real_eval and ((self.modules is None) or
(isinstance(self.modules, str) and "numpy" in self.modules)):
funcs = [f for f, c in zip(pf, check_res) if c]
warnings.warn("NumPy is unable to evaluate with complex "
"numbers some of the functions included in this "
"symbolic expression: %s. " % funcs +
"Hence, the evaluation will use real numbers. "
"If you believe the resulting plot is incorrect, "
"change the evaluation module by setting the "
"`modules` keyword argument.")
if self._functions:
# update lambda functions
self._create_lambda_func()
@property
def is_3D(self):
flags3D = [self.is_3Dline, self.is_3Dsurface, self.is_3Dvector]
return any(flags3D)
@property
def is_line(self):
flagslines = [self.is_2Dline, self.is_3Dline]
return any(flagslines)
def _line_surface_color(self, prop, val):
"""This method enables back-compatibility with old sympy.plotting"""
# NOTE: color_func is set inside the init method of the series.
# If line_color/surface_color is not a callable, then color_func will
# be set to None.
setattr(self, prop, val)
if callable(val) or isinstance(val, Expr):
self.color_func = val
setattr(self, prop, None)
elif val is not None:
self.color_func = None
@property
def line_color(self):
return self._line_color
@line_color.setter
def line_color(self, val):
self._line_surface_color("_line_color", val)
@property
def n(self):
"""Returns a list [n1, n2, n3] of numbers of discratization points.
"""
return self._n
@n.setter
def n(self, v):
"""Set the numbers of discretization points. ``v`` must be an int or
a list.
Let ``s`` be a series. Then:
* to set the number of discretization points along the x direction (or
first parameter): ``s.n = 10``
* to set the number of discretization points along the x and y
directions (or first and second parameters): ``s.n = [10, 15]``
* to set the number of discretization points along the x, y and z
directions: ``s.n = [10, 15, 20]``
The following is highly unreccomended, because it prevents
the execution of necessary code in order to keep updated data:
``s.n[1] = 15``
"""
if not hasattr(v, "__iter__"):
self._n[0] = v
else:
self._n[:len(v)] = v
if self._discretized_domain:
# update the discretized domain
self._create_discretized_domain()
@property
def params(self):
"""Get or set the current parameters dictionary.
Parameters
==========
p : dict
* key: symbol associated to the parameter
* val: the numeric value
"""
return self._params
@params.setter
def params(self, p):
self._params = p
def _post_init(self):
exprs = self.expr if hasattr(self.expr, "__iter__") else [self.expr]
if any(callable(e) for e in exprs) and self.params:
raise TypeError("`params` was provided, hence an interactive plot "
"is expected. However, interactive plots do not support "
"user-provided numerical functions.")
# if the expressions is a lambda function and no label has been
# provided, then its better to do the following in order to avoid
# suprises on the backend
if any(callable(e) for e in exprs):
if self._label == str(self.expr):
self.label = ""
self._check_fs()
if hasattr(self, "adaptive") and self.adaptive and self.params:
warnings.warn("`params` was provided, hence an interactive plot "
"is expected. However, interactive plots do not support "
"adaptive evaluation. Automatically switched to "
"adaptive=False.")
self.adaptive = False
@property
def scales(self):
return self._scales
@scales.setter
def scales(self, v):
if isinstance(v, str):
self._scales[0] = v
else:
self._scales[:len(v)] = v
@property
def surface_color(self):
return self._surface_color
@surface_color.setter
def surface_color(self, val):
self._line_surface_color("_surface_color", val)
@property
def rendering_kw(self):
return self._rendering_kw
@rendering_kw.setter
def rendering_kw(self, kwargs):
if isinstance(kwargs, dict):
self._rendering_kw = kwargs
else:
self._rendering_kw = {}
if kwargs is not None:
warnings.warn(
"`rendering_kw` must be a dictionary, instead an "
"object of type %s was received. " % type(kwargs) +
"Automatically setting `rendering_kw` to an empty "
"dictionary")
@staticmethod
def _discretize(start, end, N, scale="linear", only_integers=False):
"""Discretize a 1D domain.
Returns
=======
domain : np.ndarray with dtype=float or complex
The domain's dtype will be float or complex (depending on the
type of start/end) even if only_integers=True. It is left for
the downstream code to perform further casting, if necessary.
"""
np = import_module('numpy')
if only_integers is True:
start, end = int(start), int(end)
N = end - start + 1
if scale == "linear":
return np.linspace(start, end, N)
return np.geomspace(start, end, N)
@staticmethod
def _correct_shape(a, b):
"""Convert ``a`` to a np.ndarray of the same shape of ``b``.
Parameters
==========
a : int, float, complex, np.ndarray
Usually, this is the result of a numerical evaluation of a
symbolic expression. Even if a discretized domain was used to
evaluate the function, the result can be a scalar (int, float,
complex). Think for example to ``expr = Float(2)`` and
``f = lambdify(x, expr)``. No matter the shape of the numerical
array representing x, the result of the evaluation will be
a single value.
b : np.ndarray
It represents the correct shape that ``a`` should have.
Returns
=======
new_a : np.ndarray
An array with the correct shape.
"""
np = import_module('numpy')
if not isinstance(a, np.ndarray):
a = np.array(a)
if a.shape != b.shape:
if a.shape == ():
a = a * np.ones_like(b)
else:
a = a.reshape(b.shape)
return a
def eval_color_func(self, *args):
"""Evaluate the color function.
Parameters
==========
args : tuple
Arguments to be passed to the coloring function. Can be coordinates
or parameters or both.
Notes
=====
The backend will request the data series to generate the numerical
data. Depending on the data series, either the data series itself or
the backend will eventually execute this function to generate the
appropriate coloring value.
"""
np = import_module('numpy')
if self.color_func is None:
# NOTE: with the line_color and surface_color attributes
# (back-compatibility with the old sympy.plotting module) it is
# possible to create a plot with a callable line_color (or
# surface_color). For example:
# p = plot(sin(x), line_color=lambda x, y: -y)
# This creates a ColoredLineOver1DRangeSeries with line_color=None
# and color_func=lambda x, y: -y, which efffectively is a
# parametric series. Later we could change it to a string value:
# p[0].line_color = "red"
# However, this sets ine_color="red" and color_func=None, but the
# series is still ColoredLineOver1DRangeSeries (a parametric
# series), which will render using a color_func...
warnings.warn("This is likely not the result you were "
"looking for. Please, re-execute the plot command, this time "
"with the appropriate an appropriate value to line_color "
"or surface_color.")
return np.ones_like(args[0])
if self._eval_color_func_with_signature:
args = self._aggregate_args()
color = self.color_func(*args)
_re, _im = np.real(color), np.imag(color)
_re[np.invert(np.isclose(_im, np.zeros_like(_im)))] = np.nan
return _re
nargs = arity(self.color_func)
if nargs == 1:
if self.is_2Dline and self.is_parametric:
if len(args) == 2:
# ColoredLineOver1DRangeSeries
return self._correct_shape(self.color_func(args[0]), args[0])
# Parametric2DLineSeries
return self._correct_shape(self.color_func(args[2]), args[2])
elif self.is_3Dline and self.is_parametric:
return self._correct_shape(self.color_func(args[3]), args[3])
elif self.is_3Dsurface and self.is_parametric:
return self._correct_shape(self.color_func(args[3]), args[3])
return self._correct_shape(self.color_func(args[0]), args[0])
elif nargs == 2:
if self.is_3Dsurface and self.is_parametric:
return self._correct_shape(self.color_func(*args[3:]), args[3])
return self._correct_shape(self.color_func(*args[:2]), args[0])
return self._correct_shape(self.color_func(*args[:nargs]), args[0])
def get_data(self):
"""Compute and returns the numerical data.
The number of parameters returned by this method depends on the
specific instance. If ``s`` is the series, make sure to read
``help(s.get_data)`` to understand what it returns.
"""
raise NotImplementedError
def _get_wrapped_label(self, label, wrapper):
"""Given a latex representation of an expression, wrap it inside
some characters. Matplotlib needs "$%s%$", K3D-Jupyter needs "%s".
"""
return wrapper % label
def get_label(self, use_latex=False, wrapper="$%s$"):
"""Return the label to be used to display the expression.
Parameters
==========
use_latex : bool
If False, the string representation of the expression is returned.
If True, the latex representation is returned.
wrapper : str
The backend might need the latex representation to be wrapped by
some characters. Default to ``"$%s$"``.
Returns
=======
label : str
"""
if use_latex is False:
return self._label
if self._label == str(self.expr):
# when the backend requests a latex label and user didn't provide
# any label
return self._get_wrapped_label(self._latex_label, wrapper)
return self._latex_label
@property
def label(self):
return self.get_label()
@label.setter
def label(self, val):
"""Set the labels associated to this series."""
# NOTE: the init method of any series requires a label. If the user do
# not provide it, the preprocessing function will set label=None, which
# informs the series to initialize two attributes:
# _label contains the string representation of the expression.
# _latex_label contains the latex representation of the expression.
self._label = self._latex_label = val
@property
def ranges(self):
return self._ranges
@ranges.setter
def ranges(self, val):
new_vals = []
for v in val:
if v is not None:
new_vals.append(tuple([sympify(t) for t in v]))
self._ranges = new_vals
def _apply_transform(self, *args):
"""Apply transformations to the results of numerical evaluation.
Parameters
==========
args : tuple
Results of numerical evaluation.
Returns
=======
transformed_args : tuple
Tuple containing the transformed results.
"""
t = lambda x, transform: x if transform is None else transform(x)
x, y, z = None, None, None
if len(args) == 2:
x, y = args
return t(x, self._tx), t(y, self._ty)
elif (len(args) == 3) and isinstance(self, Parametric2DLineSeries):
x, y, u = args
return (t(x, self._tx), t(y, self._ty), t(u, self._tp))
elif len(args) == 3:
x, y, z = args
return t(x, self._tx), t(y, self._ty), t(z, self._tz)
elif (len(args) == 4) and isinstance(self, Parametric3DLineSeries):
x, y, z, u = args
return (t(x, self._tx), t(y, self._ty), t(z, self._tz), t(u, self._tp))
elif len(args) == 4: # 2D vector plot
x, y, u, v = args
return (
t(x, self._tx), t(y, self._ty),
t(u, self._tx), t(v, self._ty)
)
elif (len(args) == 5) and isinstance(self, ParametricSurfaceSeries):
x, y, z, u, v = args
return (t(x, self._tx), t(y, self._ty), t(z, self._tz), u, v)
elif (len(args) == 6) and self.is_3Dvector: # 3D vector plot
x, y, z, u, v, w = args
return (
t(x, self._tx), t(y, self._ty), t(z, self._tz),
t(u, self._tx), t(v, self._ty), t(w, self._tz)
)
elif len(args) == 6: # complex plot
x, y, _abs, _arg, img, colors = args
return (
x, y, t(_abs, self._tz), _arg, img, colors)
return args
def _str_helper(self, s):
pre, post = "", ""
if self.is_interactive:
pre = "interactive "
post = " and parameters " + str(tuple(self.params.keys()))
return pre + s + post
def _detect_poles_numerical_helper(x, y, eps=0.01, expr=None, symb=None, symbolic=False):
"""Compute the steepness of each segment. If it's greater than a
threshold, set the right-point y-value non NaN and record the
corresponding x-location for further processing.
Returns
=======
x : np.ndarray
Unchanged x-data.
yy : np.ndarray
Modified y-data with NaN values.
"""
np = import_module('numpy')
yy = y.copy()
threshold = np.pi / 2 - eps
for i in range(len(x) - 1):
dx = x[i + 1] - x[i]
dy = abs(y[i + 1] - y[i])
angle = np.arctan(dy / dx)
if abs(angle) >= threshold:
yy[i + 1] = np.nan
return x, yy
def _detect_poles_symbolic_helper(expr, symb, start, end):
"""Attempts to compute symbolic discontinuities.
Returns
=======
pole : list
List of symbolic poles, possibily empty.
"""
poles = []
interval = Interval(nsimplify(start), nsimplify(end))
res = continuous_domain(expr, symb, interval)
res = res.simplify()
if res == interval:
pass
elif (isinstance(res, Union) and
all(isinstance(t, Interval) for t in res.args)):
poles = []
for s in res.args:
if s.left_open:
poles.append(s.left)
if s.right_open:
poles.append(s.right)
poles = list(set(poles))
else:
raise ValueError(
f"Could not parse the following object: {res} .\n"
"Please, submit this as a bug. Consider also to set "
"`detect_poles=True`."
)
return poles
### 2D lines
class Line2DBaseSeries(BaseSeries):
"""A base class for 2D lines.
- adding the label, steps and only_integers options
- making is_2Dline true
- defining get_segments and get_color_array
"""
is_2Dline = True
_dim = 2
_N = 1000
def __init__(self, **kwargs):
super().__init__(**kwargs)
self.steps = kwargs.get("steps", False)
self.is_point = kwargs.get("is_point", kwargs.get("point", False))
self.is_filled = kwargs.get("is_filled", kwargs.get("fill", True))
self.adaptive = kwargs.get("adaptive", False)
self.depth = kwargs.get('depth', 12)
self.use_cm = kwargs.get("use_cm", False)
self.color_func = kwargs.get("color_func", None)
self.line_color = kwargs.get("line_color", None)
self.detect_poles = kwargs.get("detect_poles", False)
self.eps = kwargs.get("eps", 0.01)
self.is_polar = kwargs.get("is_polar", kwargs.get("polar", False))
self.unwrap = kwargs.get("unwrap", False)
# when detect_poles="symbolic", stores the location of poles so that
# they can be appropriately rendered
self.poles_locations = []
exclude = kwargs.get("exclude", [])
if isinstance(exclude, Set):
exclude = list(extract_solution(exclude, n=100))
if not hasattr(exclude, "__iter__"):
exclude = [exclude]
exclude = [float(e) for e in exclude]
self.exclude = sorted(exclude)
def get_data(self):
"""Return coordinates for plotting the line.
Returns
=======
x: np.ndarray
x-coordinates
y: np.ndarray
y-coordinates
z: np.ndarray (optional)
z-coordinates in case of Parametric3DLineSeries,
Parametric3DLineInteractiveSeries
param : np.ndarray (optional)
The parameter in case of Parametric2DLineSeries,
Parametric3DLineSeries or AbsArgLineSeries (and their
corresponding interactive series).
"""
np = import_module('numpy')
points = self._get_data_helper()
if (isinstance(self, LineOver1DRangeSeries) and
(self.detect_poles == "symbolic")):
poles = _detect_poles_symbolic_helper(
self.expr.subs(self.params), *self.ranges[0])
poles = np.array([float(t) for t in poles])
t = lambda x, transform: x if transform is None else transform(x)
self.poles_locations = t(np.array(poles), self._tx)
# postprocessing
points = self._apply_transform(*points)
if self.is_2Dline and self.detect_poles:
if len(points) == 2:
x, y = points
x, y = _detect_poles_numerical_helper(
x, y, self.eps)
points = (x, y)
else:
x, y, p = points
x, y = _detect_poles_numerical_helper(x, y, self.eps)
points = (x, y, p)
if self.unwrap:
kw = {}
if self.unwrap is not True:
kw = self.unwrap
if self.is_2Dline:
if len(points) == 2:
x, y = points
y = np.unwrap(y, **kw)
points = (x, y)
else:
x, y, p = points
y = np.unwrap(y, **kw)
points = (x, y, p)
if self.steps is True:
if self.is_2Dline:
x, y = points[0], points[1]
x = np.array((x, x)).T.flatten()[1:]
y = np.array((y, y)).T.flatten()[:-1]
if self.is_parametric:
points = (x, y, points[2])
else:
points = (x, y)
elif self.is_3Dline:
x = np.repeat(points[0], 3)[2:]
y = np.repeat(points[1], 3)[:-2]
z = np.repeat(points[2], 3)[1:-1]
if len(points) > 3:
points = (x, y, z, points[3])
else:
points = (x, y, z)
if len(self.exclude) > 0:
points = self._insert_exclusions(points)
return points
def get_segments(self):
sympy_deprecation_warning(
"""
The Line2DBaseSeries.get_segments() method is deprecated.
Instead, use the MatplotlibBackend.get_segments() method, or use
The get_points() or get_data() methods.
""",
deprecated_since_version="1.9",
active_deprecations_target="deprecated-get-segments")
np = import_module('numpy')
points = type(self).get_data(self)
points = np.ma.array(points).T.reshape(-1, 1, self._dim)
return np.ma.concatenate([points[:-1], points[1:]], axis=1)
def _insert_exclusions(self, points):
"""Add NaN to each of the exclusion point. Practically, this adds a
NaN to the exlusion point, plus two other nearby points evaluated with
the numerical functions associated to this data series.
These nearby points are important when the number of discretization
points is low, or the scale is logarithm.
NOTE: it would be easier to just add exclusion points to the
discretized domain before evaluation, then after evaluation add NaN
to the exclusion points. But that's only work with adaptive=False.
The following approach work even with adaptive=True.
"""
np = import_module("numpy")
points = list(points)
n = len(points)
# index of the x-coordinate (for 2d plots) or parameter (for 2d/3d
# parametric plots)
k = n - 1
if n == 2:
k = 0
# indeces of the other coordinates
j_indeces = sorted(set(range(n)).difference([k]))
# TODO: for now, I assume that numpy functions are going to succeed
funcs = [f[0] for f in self._functions]
for e in self.exclude:
res = points[k] - e >= 0
# if res contains both True and False, ie, if e is found
if any(res) and any(~res):
idx = np.nanargmax(res)
# select the previous point with respect to e
idx -= 1
# TODO: what if points[k][idx]==e or points[k][idx+1]==e?
if idx > 0 and idx < len(points[k]) - 1:
delta_prev = abs(e - points[k][idx])
delta_post = abs(e - points[k][idx + 1])
delta = min(delta_prev, delta_post) / 100
prev = e - delta
post = e + delta
# add points to the x-coord or the parameter
points[k] = np.concatenate(
(points[k][:idx], [prev, e, post], points[k][idx+1:]))
# add points to the other coordinates
c = 0
for j in j_indeces:
values = funcs[c](np.array([prev, post]))
c += 1
points[j] = np.concatenate(
(points[j][:idx], [values[0], np.nan, values[1]], points[j][idx+1:]))
return points
@property
def var(self):
return None if not self.ranges else self.ranges[0][0]
@property
def start(self):
if not self.ranges:
return None
try:
return self._cast(self.ranges[0][1])
except TypeError:
return self.ranges[0][1]
@property
def end(self):
if not self.ranges:
return None
try:
return self._cast(self.ranges[0][2])
except TypeError:
return self.ranges[0][2]
@property
def xscale(self):
return self._scales[0]
@xscale.setter
def xscale(self, v):
self.scales = v
def get_color_array(self):
np = import_module('numpy')
c = self.line_color
if hasattr(c, '__call__'):
f = np.vectorize(c)
nargs = arity(c)
if nargs == 1 and self.is_parametric:
x = self.get_parameter_points()
return f(centers_of_segments(x))
else:
variables = list(map(centers_of_segments, self.get_points()))
if nargs == 1:
return f(variables[0])
elif nargs == 2:
return f(*variables[:2])
else: # only if the line is 3D (otherwise raises an error)
return f(*variables)
else:
return c*np.ones(self.nb_of_points)
class List2DSeries(Line2DBaseSeries):
"""Representation for a line consisting of list of points."""
def __init__(self, list_x, list_y, label="", **kwargs):
super().__init__(**kwargs)
np = import_module('numpy')
if len(list_x) != len(list_y):
raise ValueError(
"The two lists of coordinates must have the same "
"number of elements.\n"
"Received: len(list_x) = {} ".format(len(list_x)) +
"and len(list_y) = {}".format(len(list_y))
)
self._block_lambda_functions(list_x, list_y)
check = lambda l: [isinstance(t, Expr) and (not t.is_number) for t in l]
if any(check(list_x) + check(list_y)) or self.params:
if not self.params:
raise ValueError("Some or all elements of the provided lists "
"are symbolic expressions, but the ``params`` dictionary "
"was not provided: those elements can't be evaluated.")
self.list_x = Tuple(*list_x)
self.list_y = Tuple(*list_y)
else:
self.list_x = np.array(list_x, dtype=np.float64)
self.list_y = np.array(list_y, dtype=np.float64)
self._expr = (self.list_x, self.list_y)
if not any(isinstance(t, np.ndarray) for t in [self.list_x, self.list_y]):
self._check_fs()
self.is_polar = kwargs.get("is_polar", kwargs.get("polar", False))
self.label = label
self.rendering_kw = kwargs.get("rendering_kw", {})
if self.use_cm and self.color_func:
self.is_parametric = True
if isinstance(self.color_func, Expr):
raise TypeError(
"%s don't support symbolic " % self.__class__.__name__ +
"expression for `color_func`.")
def __str__(self):
return "2D list plot"
def _get_data_helper(self):
"""Returns coordinates that needs to be postprocessed."""
lx, ly = self.list_x, self.list_y
if not self.is_interactive:
return self._eval_color_func_and_return(lx, ly)
np = import_module('numpy')
lx = np.array([t.evalf(subs=self.params) for t in lx], dtype=float)
ly = np.array([t.evalf(subs=self.params) for t in ly], dtype=float)
return self._eval_color_func_and_return(lx, ly)
def _eval_color_func_and_return(self, *data):
if self.use_cm and callable(self.color_func):
return [*data, self.eval_color_func(*data)]
return data
class LineOver1DRangeSeries(Line2DBaseSeries):
"""Representation for a line consisting of a SymPy expression over a range."""
def __init__(self, expr, var_start_end, label="", **kwargs):
super().__init__(**kwargs)
self.expr = expr if callable(expr) else sympify(expr)
self._label = str(self.expr) if label is None else label
self._latex_label = latex(self.expr) if label is None else label
self.ranges = [var_start_end]
self._cast = complex
# for complex-related data series, this determines what data to return
# on the y-axis
self._return = kwargs.get("return", None)
self._post_init()
if not self._interactive_ranges:
# NOTE: the following check is only possible when the minimum and
# maximum values of a plotting range are numeric
start, end = [complex(t) for t in self.ranges[0][1:]]
if im(start) != im(end):
raise ValueError(
"%s requires the imaginary " % self.__class__.__name__ +
"part of the start and end values of the range "
"to be the same.")
if self.adaptive and self._return:
warnings.warn("The adaptive algorithm is unable to deal with "
"complex numbers. Automatically switching to uniform meshing.")
self.adaptive = False
@property
def nb_of_points(self):
return self.n[0]
@nb_of_points.setter
def nb_of_points(self, v):
self.n = v
def __str__(self):
def f(t):
if isinstance(t, complex):
if t.imag != 0:
return t
return t.real
return t
pre = "interactive " if self.is_interactive else ""
post = ""
if self.is_interactive:
post = " and parameters " + str(tuple(self.params.keys()))
wrapper = _get_wrapper_for_expr(self._return)
return pre + "cartesian line: %s for %s over %s" % (
wrapper % self.expr,
str(self.var),
str((f(self.start), f(self.end))),
) + post
def get_points(self):
"""Return lists of coordinates for plotting. Depending on the
``adaptive`` option, this function will either use an adaptive algorithm
or it will uniformly sample the expression over the provided range.
This function is available for back-compatibility purposes. Consider
using ``get_data()`` instead.
Returns
=======
x : list
List of x-coordinates
y : list
List of y-coordinates
"""
return self._get_data_helper()
def _adaptive_sampling(self):
try:
if callable(self.expr):
f = self.expr
else:
f = lambdify([self.var], self.expr, self.modules)
x, y = self._adaptive_sampling_helper(f)
except Exception as err:
warnings.warn(
"The evaluation with %s failed.\n" % (
"NumPy/SciPy" if not self.modules else self.modules) +
"{}: {}\n".format(type(err).__name__, err) +
"Trying to evaluate the expression with Sympy, but it might "
"be a slow operation."
)
f = lambdify([self.var], self.expr, "sympy")
x, y = self._adaptive_sampling_helper(f)
return x, y
def _adaptive_sampling_helper(self, f):
"""The adaptive sampling is done by recursively checking if three
points are almost collinear. If they are not collinear, then more
points are added between those points.
References
==========
.. [1] Adaptive polygonal approximation of parametric curves,
Luiz Henrique de Figueiredo.
"""
np = import_module('numpy')
x_coords = []
y_coords = []
def sample(p, q, depth):
""" Samples recursively if three points are almost collinear.
For depth < 6, points are added irrespective of whether they
satisfy the collinearity condition or not. The maximum depth
allowed is 12.
"""
# Randomly sample to avoid aliasing.
random = 0.45 + np.random.rand() * 0.1
if self.xscale == 'log':
xnew = 10**(np.log10(p[0]) + random * (np.log10(q[0]) -
np.log10(p[0])))
else:
xnew = p[0] + random * (q[0] - p[0])
ynew = _adaptive_eval(f, xnew)
new_point = np.array([xnew, ynew])
# Maximum depth
if depth > self.depth:
x_coords.append(q[0])
y_coords.append(q[1])
# Sample to depth of 6 (whether the line is flat or not)
# without using linspace (to avoid aliasing).
elif depth < 6:
sample(p, new_point, depth + 1)
sample(new_point, q, depth + 1)
# Sample ten points if complex values are encountered
# at both ends. If there is a real value in between, then
# sample those points further.
elif p[1] is None and q[1] is None:
if self.xscale == 'log':
xarray = np.logspace(p[0], q[0], 10)
else:
xarray = np.linspace(p[0], q[0], 10)
yarray = list(map(f, xarray))
if not all(y is None for y in yarray):
for i in range(len(yarray) - 1):
if not (yarray[i] is None and yarray[i + 1] is None):
sample([xarray[i], yarray[i]],
[xarray[i + 1], yarray[i + 1]], depth + 1)
# Sample further if one of the end points in None (i.e. a
# complex value) or the three points are not almost collinear.
elif (p[1] is None or q[1] is None or new_point[1] is None
or not flat(p, new_point, q)):
sample(p, new_point, depth + 1)
sample(new_point, q, depth + 1)
else:
x_coords.append(q[0])
y_coords.append(q[1])
f_start = _adaptive_eval(f, self.start.real)
f_end = _adaptive_eval(f, self.end.real)
x_coords.append(self.start.real)
y_coords.append(f_start)
sample(np.array([self.start.real, f_start]),
np.array([self.end.real, f_end]), 0)
return (x_coords, y_coords)
def _uniform_sampling(self):
np = import_module('numpy')
x, result = self._evaluate()
_re, _im = np.real(result), np.imag(result)
_re = self._correct_shape(_re, x)
_im = self._correct_shape(_im, x)
return x, _re, _im
def _get_data_helper(self):
"""Returns coordinates that needs to be postprocessed.
"""
np = import_module('numpy')
if self.adaptive and (not self.only_integers):
x, y = self._adaptive_sampling()
return [np.array(t) for t in [x, y]]
x, _re, _im = self._uniform_sampling()
if self._return is None:
# The evaluation could produce complex numbers. Set real elements
# to NaN where there are non-zero imaginary elements
_re[np.invert(np.isclose(_im, np.zeros_like(_im)))] = np.nan
elif self._return == "real":
pass
elif self._return == "imag":
_re = _im
elif self._return == "abs":
_re = np.sqrt(_re**2 + _im**2)
elif self._return == "arg":
_re = np.arctan2(_im, _re)
else:
raise ValueError("`_return` not recognized. "
"Received: %s" % self._return)
return x, _re
class ParametricLineBaseSeries(Line2DBaseSeries):
is_parametric = True
def _set_parametric_line_label(self, label):
"""Logic to set the correct label to be shown on the plot.
If `use_cm=True` there will be a colorbar, so we show the parameter.
If `use_cm=False`, there might be a legend, so we show the expressions.
Parameters
==========
label : str
label passed in by the pre-processor or the user
"""
self._label = str(self.var) if label is None else label
self._latex_label = latex(self.var) if label is None else label
if (self.use_cm is False) and (self._label == str(self.var)):
self._label = str(self.expr)
self._latex_label = latex(self.expr)
# if the expressions is a lambda function and use_cm=False and no label
# has been provided, then its better to do the following in order to
# avoid suprises on the backend
if any(callable(e) for e in self.expr) and (not self.use_cm):
if self._label == str(self.expr):
self._label = ""
def get_label(self, use_latex=False, wrapper="$%s$"):
# parametric lines returns the representation of the parameter to be
# shown on the colorbar if `use_cm=True`, otherwise it returns the
# representation of the expression to be placed on the legend.
if self.use_cm:
if str(self.var) == self._label:
if use_latex:
return self._get_wrapped_label(latex(self.var), wrapper)
return str(self.var)
# here the user has provided a custom label
return self._label
if use_latex:
if self._label != str(self.expr):
return self._latex_label
return self._get_wrapped_label(self._latex_label, wrapper)
return self._label
def _get_data_helper(self):
"""Returns coordinates that needs to be postprocessed.
Depending on the `adaptive` option, this function will either use an
adaptive algorithm or it will uniformly sample the expression over the
provided range.
"""
if self.adaptive:
np = import_module("numpy")
coords = self._adaptive_sampling()
coords = [np.array(t) for t in coords]
else:
coords = self._uniform_sampling()
if self.is_2Dline and self.is_polar:
# when plot_polar is executed with polar_axis=True
np = import_module('numpy')
x, y, _ = coords
r = np.sqrt(x**2 + y**2)
t = np.arctan2(y, x)
coords = [t, r, coords[-1]]
if callable(self.color_func):
coords = list(coords)
coords[-1] = self.eval_color_func(*coords)
return coords
def _uniform_sampling(self):
"""Returns coordinates that needs to be postprocessed."""
np = import_module('numpy')
results = self._evaluate()
for i, r in enumerate(results):
_re, _im = np.real(r), np.imag(r)
_re[np.invert(np.isclose(_im, np.zeros_like(_im)))] = np.nan
results[i] = _re
return [*results[1:], results[0]]
def get_parameter_points(self):
return self.get_data()[-1]
def get_points(self):
""" Return lists of coordinates for plotting. Depending on the
``adaptive`` option, this function will either use an adaptive algorithm
or it will uniformly sample the expression over the provided range.
This function is available for back-compatibility purposes. Consider
using ``get_data()`` instead.
Returns
=======
x : list
List of x-coordinates
y : list
List of y-coordinates
z : list
List of z-coordinates, only for 3D parametric line plot.
"""
return self._get_data_helper()[:-1]
@property
def nb_of_points(self):
return self.n[0]
@nb_of_points.setter
def nb_of_points(self, v):
self.n = v
class Parametric2DLineSeries(ParametricLineBaseSeries):
"""Representation for a line consisting of two parametric SymPy expressions
over a range."""
is_2Dline = True
def __init__(self, expr_x, expr_y, var_start_end, label="", **kwargs):
super().__init__(**kwargs)
self.expr_x = expr_x if callable(expr_x) else sympify(expr_x)
self.expr_y = expr_y if callable(expr_y) else sympify(expr_y)
self.expr = (self.expr_x, self.expr_y)
self.ranges = [var_start_end]
self._cast = float
self.use_cm = kwargs.get("use_cm", True)
self._set_parametric_line_label(label)
self._post_init()
def __str__(self):
return self._str_helper(
"parametric cartesian line: (%s, %s) for %s over %s" % (
str(self.expr_x),
str(self.expr_y),
str(self.var),
str((self.start, self.end))
))
def _adaptive_sampling(self):
try:
if callable(self.expr_x) and callable(self.expr_y):
f_x = self.expr_x
f_y = self.expr_y
else:
f_x = lambdify([self.var], self.expr_x)
f_y = lambdify([self.var], self.expr_y)
x, y, p = self._adaptive_sampling_helper(f_x, f_y)
except Exception as err:
warnings.warn(
"The evaluation with %s failed.\n" % (
"NumPy/SciPy" if not self.modules else self.modules) +
"{}: {}\n".format(type(err).__name__, err) +
"Trying to evaluate the expression with Sympy, but it might "
"be a slow operation."
)
f_x = lambdify([self.var], self.expr_x, "sympy")
f_y = lambdify([self.var], self.expr_y, "sympy")
x, y, p = self._adaptive_sampling_helper(f_x, f_y)
return x, y, p
def _adaptive_sampling_helper(self, f_x, f_y):
"""The adaptive sampling is done by recursively checking if three
points are almost collinear. If they are not collinear, then more
points are added between those points.
References
==========
.. [1] Adaptive polygonal approximation of parametric curves,
Luiz Henrique de Figueiredo.
"""
x_coords = []
y_coords = []
param = []
def sample(param_p, param_q, p, q, depth):
""" Samples recursively if three points are almost collinear.
For depth < 6, points are added irrespective of whether they
satisfy the collinearity condition or not. The maximum depth
allowed is 12.
"""
# Randomly sample to avoid aliasing.
np = import_module('numpy')
random = 0.45 + np.random.rand() * 0.1
param_new = param_p + random * (param_q - param_p)
xnew = _adaptive_eval(f_x, param_new)
ynew = _adaptive_eval(f_y, param_new)
new_point = np.array([xnew, ynew])
# Maximum depth
if depth > self.depth:
x_coords.append(q[0])
y_coords.append(q[1])
param.append(param_p)
# Sample irrespective of whether the line is flat till the
# depth of 6. We are not using linspace to avoid aliasing.
elif depth < 6:
sample(param_p, param_new, p, new_point, depth + 1)
sample(param_new, param_q, new_point, q, depth + 1)
# Sample ten points if complex values are encountered
# at both ends. If there is a real value in between, then
# sample those points further.
elif ((p[0] is None and q[1] is None) or
(p[1] is None and q[1] is None)):
param_array = np.linspace(param_p, param_q, 10)
x_array = [_adaptive_eval(f_x, t) for t in param_array]
y_array = [_adaptive_eval(f_y, t) for t in param_array]
if not all(x is None and y is None
for x, y in zip(x_array, y_array)):
for i in range(len(y_array) - 1):
if ((x_array[i] is not None and y_array[i] is not None) or
(x_array[i + 1] is not None and y_array[i + 1] is not None)):
point_a = [x_array[i], y_array[i]]
point_b = [x_array[i + 1], y_array[i + 1]]
sample(param_array[i], param_array[i], point_a,
point_b, depth + 1)
# Sample further if one of the end points in None (i.e. a complex
# value) or the three points are not almost collinear.
elif (p[0] is None or p[1] is None
or q[1] is None or q[0] is None
or not flat(p, new_point, q)):
sample(param_p, param_new, p, new_point, depth + 1)
sample(param_new, param_q, new_point, q, depth + 1)
else:
x_coords.append(q[0])
y_coords.append(q[1])
param.append(param_p)
f_start_x = _adaptive_eval(f_x, self.start)
f_start_y = _adaptive_eval(f_y, self.start)
start = [f_start_x, f_start_y]
f_end_x = _adaptive_eval(f_x, self.end)
f_end_y = _adaptive_eval(f_y, self.end)
end = [f_end_x, f_end_y]
x_coords.append(f_start_x)
y_coords.append(f_start_y)
param.append(self.start)
sample(self.start, self.end, start, end, 0)
return x_coords, y_coords, param
### 3D lines
class Line3DBaseSeries(Line2DBaseSeries):
"""A base class for 3D lines.
Most of the stuff is derived from Line2DBaseSeries."""
is_2Dline = False
is_3Dline = True
_dim = 3
def __init__(self):
super().__init__()
class Parametric3DLineSeries(ParametricLineBaseSeries):
"""Representation for a 3D line consisting of three parametric SymPy
expressions and a range."""
is_2Dline = False
is_3Dline = True
def __init__(self, expr_x, expr_y, expr_z, var_start_end, label="", **kwargs):
super().__init__(**kwargs)
self.expr_x = expr_x if callable(expr_x) else sympify(expr_x)
self.expr_y = expr_y if callable(expr_y) else sympify(expr_y)
self.expr_z = expr_z if callable(expr_z) else sympify(expr_z)
self.expr = (self.expr_x, self.expr_y, self.expr_z)
self.ranges = [var_start_end]
self._cast = float
self.adaptive = False
self.use_cm = kwargs.get("use_cm", True)
self._set_parametric_line_label(label)
self._post_init()
# TODO: remove this
self._xlim = None
self._ylim = None
self._zlim = None
def __str__(self):
return self._str_helper(
"3D parametric cartesian line: (%s, %s, %s) for %s over %s" % (
str(self.expr_x),
str(self.expr_y),
str(self.expr_z),
str(self.var),
str((self.start, self.end))
))
def get_data(self):
# TODO: remove this
np = import_module("numpy")
x, y, z, p = super().get_data()
self._xlim = (np.amin(x), np.amax(x))
self._ylim = (np.amin(y), np.amax(y))
self._zlim = (np.amin(z), np.amax(z))
return x, y, z, p
### Surfaces
class SurfaceBaseSeries(BaseSeries):
"""A base class for 3D surfaces."""
is_3Dsurface = True
def __init__(self, *args, **kwargs):
super().__init__(**kwargs)
self.use_cm = kwargs.get("use_cm", False)
# NOTE: why should SurfaceOver2DRangeSeries support is polar?
# After all, the same result can be achieve with
# ParametricSurfaceSeries. For example:
# sin(r) for (r, 0, 2 * pi) and (theta, 0, pi/2) can be parameterized
# as (r * cos(theta), r * sin(theta), sin(t)) for (r, 0, 2 * pi) and
# (theta, 0, pi/2).
# Because it is faster to evaluate (important for interactive plots).
self.is_polar = kwargs.get("is_polar", kwargs.get("polar", False))
self.surface_color = kwargs.get("surface_color", None)
self.color_func = kwargs.get("color_func", lambda x, y, z: z)
if callable(self.surface_color):
self.color_func = self.surface_color
self.surface_color = None
def _set_surface_label(self, label):
exprs = self.expr
self._label = str(exprs) if label is None else label
self._latex_label = latex(exprs) if label is None else label
# if the expressions is a lambda function and no label
# has been provided, then its better to do the following to avoid
# suprises on the backend
is_lambda = (callable(exprs) if not hasattr(exprs, "__iter__")
else any(callable(e) for e in exprs))
if is_lambda and (self._label == str(exprs)):
self._label = ""
self._latex_label = ""
def get_color_array(self):
np = import_module('numpy')
c = self.surface_color
if isinstance(c, Callable):
f = np.vectorize(c)
nargs = arity(c)
if self.is_parametric:
variables = list(map(centers_of_faces, self.get_parameter_meshes()))
if nargs == 1:
return f(variables[0])
elif nargs == 2:
return f(*variables)
variables = list(map(centers_of_faces, self.get_meshes()))
if nargs == 1:
return f(variables[0])
elif nargs == 2:
return f(*variables[:2])
else:
return f(*variables)
else:
if isinstance(self, SurfaceOver2DRangeSeries):
return c*np.ones(min(self.nb_of_points_x, self.nb_of_points_y))
else:
return c*np.ones(min(self.nb_of_points_u, self.nb_of_points_v))
class SurfaceOver2DRangeSeries(SurfaceBaseSeries):
"""Representation for a 3D surface consisting of a SymPy expression and 2D
range."""
def __init__(self, expr, var_start_end_x, var_start_end_y, label="", **kwargs):
super().__init__(**kwargs)
self.expr = expr if callable(expr) else sympify(expr)
self.ranges = [var_start_end_x, var_start_end_y]
self._set_surface_label(label)
self._post_init()
# TODO: remove this
self._xlim = (self.start_x, self.end_x)
self._ylim = (self.start_y, self.end_y)
@property
def var_x(self):
return self.ranges[0][0]
@property
def var_y(self):
return self.ranges[1][0]
@property
def start_x(self):
try:
return float(self.ranges[0][1])
except TypeError:
return self.ranges[0][1]
@property
def end_x(self):
try:
return float(self.ranges[0][2])
except TypeError:
return self.ranges[0][2]
@property
def start_y(self):
try:
return float(self.ranges[1][1])
except TypeError:
return self.ranges[1][1]
@property
def end_y(self):
try:
return float(self.ranges[1][2])
except TypeError:
return self.ranges[1][2]
@property
def nb_of_points_x(self):
return self.n[0]
@nb_of_points_x.setter
def nb_of_points_x(self, v):
n = self.n
self.n = [v, n[1:]]
@property
def nb_of_points_y(self):
return self.n[1]
@nb_of_points_y.setter
def nb_of_points_y(self, v):
n = self.n
self.n = [n[0], v, n[2]]
def __str__(self):
series_type = "cartesian surface" if self.is_3Dsurface else "contour"
return self._str_helper(
series_type + ": %s for" " %s over %s and %s over %s" % (
str(self.expr),
str(self.var_x), str((self.start_x, self.end_x)),
str(self.var_y), str((self.start_y, self.end_y)),
))
def get_meshes(self):
"""Return the x,y,z coordinates for plotting the surface.
This function is available for back-compatibility purposes. Consider
using ``get_data()`` instead.
"""
return self.get_data()
def get_data(self):
"""Return arrays of coordinates for plotting.
Returns
=======
mesh_x : np.ndarray
Discretized x-domain.
mesh_y : np.ndarray
Discretized y-domain.
mesh_z : np.ndarray
Results of the evaluation.
"""
np = import_module('numpy')
results = self._evaluate()
# mask out complex values
for i, r in enumerate(results):
_re, _im = np.real(r), np.imag(r)
_re[np.invert(np.isclose(_im, np.zeros_like(_im)))] = np.nan
results[i] = _re
x, y, z = results
if self.is_polar and self.is_3Dsurface:
r = x.copy()
x = r * np.cos(y)
y = r * np.sin(y)
# TODO: remove this
self._zlim = (np.amin(z), np.amax(z))
return self._apply_transform(x, y, z)
class ParametricSurfaceSeries(SurfaceBaseSeries):
"""Representation for a 3D surface consisting of three parametric SymPy
expressions and a range."""
is_parametric = True
def __init__(self, expr_x, expr_y, expr_z,
var_start_end_u, var_start_end_v, label="", **kwargs):
super().__init__(**kwargs)
self.expr_x = expr_x if callable(expr_x) else sympify(expr_x)
self.expr_y = expr_y if callable(expr_y) else sympify(expr_y)
self.expr_z = expr_z if callable(expr_z) else sympify(expr_z)
self.expr = (self.expr_x, self.expr_y, self.expr_z)
self.ranges = [var_start_end_u, var_start_end_v]
self.color_func = kwargs.get("color_func", lambda x, y, z, u, v: z)
self._set_surface_label(label)
self._post_init()
@property
def var_u(self):
return self.ranges[0][0]
@property
def var_v(self):
return self.ranges[1][0]
@property
def start_u(self):
try:
return float(self.ranges[0][1])
except TypeError:
return self.ranges[0][1]
@property
def end_u(self):
try:
return float(self.ranges[0][2])
except TypeError:
return self.ranges[0][2]
@property
def start_v(self):
try:
return float(self.ranges[1][1])
except TypeError:
return self.ranges[1][1]
@property
def end_v(self):
try:
return float(self.ranges[1][2])
except TypeError:
return self.ranges[1][2]
@property
def nb_of_points_u(self):
return self.n[0]
@nb_of_points_u.setter
def nb_of_points_u(self, v):
n = self.n
self.n = [v, n[1:]]
@property
def nb_of_points_v(self):
return self.n[1]
@nb_of_points_v.setter
def nb_of_points_v(self, v):
n = self.n
self.n = [n[0], v, n[2]]
def __str__(self):
return self._str_helper(
"parametric cartesian surface: (%s, %s, %s) for"
" %s over %s and %s over %s" % (
str(self.expr_x), str(self.expr_y), str(self.expr_z),
str(self.var_u), str((self.start_u, self.end_u)),
str(self.var_v), str((self.start_v, self.end_v)),
))
def get_parameter_meshes(self):
return self.get_data()[3:]
def get_meshes(self):
"""Return the x,y,z coordinates for plotting the surface.
This function is available for back-compatibility purposes. Consider
using ``get_data()`` instead.
"""
return self.get_data()[:3]
def get_data(self):
"""Return arrays of coordinates for plotting.
Returns
=======
x : np.ndarray [n2 x n1]
x-coordinates.
y : np.ndarray [n2 x n1]
y-coordinates.
z : np.ndarray [n2 x n1]
z-coordinates.
mesh_u : np.ndarray [n2 x n1]
Discretized u range.
mesh_v : np.ndarray [n2 x n1]
Discretized v range.
"""
np = import_module('numpy')
results = self._evaluate()
# mask out complex values
for i, r in enumerate(results):
_re, _im = np.real(r), np.imag(r)
_re[np.invert(np.isclose(_im, np.zeros_like(_im)))] = np.nan
results[i] = _re
# TODO: remove this
x, y, z = results[2:]
self._xlim = (np.amin(x), np.amax(x))
self._ylim = (np.amin(y), np.amax(y))
self._zlim = (np.amin(z), np.amax(z))
return self._apply_transform(*results[2:], *results[:2])
### Contours
class ContourSeries(SurfaceOver2DRangeSeries):
"""Representation for a contour plot."""
is_3Dsurface = False
is_contour = True
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.is_filled = kwargs.get("is_filled", kwargs.get("fill", True))
self.show_clabels = kwargs.get("clabels", True)
# NOTE: contour plots are used by plot_contour, plot_vector and
# plot_complex_vector. By implementing contour_kw we are able to
# quickly target the contour plot.
self.rendering_kw = kwargs.get("contour_kw",
kwargs.get("rendering_kw", {}))
class GenericDataSeries(BaseSeries):
"""Represents generic numerical data.
Notes
=====
This class serves the purpose of back-compatibility with the "markers,
annotations, fill, rectangles" keyword arguments that represent
user-provided numerical data. In particular, it solves the problem of
combining together two or more plot-objects with the ``extend`` or
``append`` methods: user-provided numerical data is also taken into
consideration because it is stored in this series class.
Also note that the current implementation is far from optimal, as each
keyword argument is stored into an attribute in the ``Plot`` class, which
requires a hard-coded if-statement in the ``MatplotlibBackend`` class.
The implementation suggests that it is ok to add attributes and
if-statements to provide more and more functionalities for user-provided
numerical data (e.g. adding horizontal lines, or vertical lines, or bar
plots, etc). However, in doing so one would reinvent the wheel: plotting
libraries (like Matplotlib) already implements the necessary API.
Instead of adding more keyword arguments and attributes, users interested
in adding custom numerical data to a plot should retrieve the figure
created by this plotting module. For example, this code:
.. plot::
:context: close-figs
:include-source: True
from sympy import Symbol, plot, cos
x = Symbol("x")
p = plot(cos(x), markers=[{"args": [[0, 1, 2], [0, 1, -1], "*"]}])
Becomes:
.. plot::
:context: close-figs
:include-source: True
p = plot(cos(x), backend="matplotlib")
fig, ax = p._backend.fig, p._backend.ax[0]
ax.plot([0, 1, 2], [0, 1, -1], "*")
fig
Which is far better in terms of readibility. Also, it gives access to the
full plotting library capabilities, without the need to reinvent the wheel.
"""
is_generic = True
def __init__(self, tp, *args, **kwargs):
self.type = tp
self.args = args
self.rendering_kw = kwargs
def get_data(self):
return self.args
class ImplicitSeries(BaseSeries):
"""Representation for 2D Implicit plot."""
is_implicit = True
use_cm = False
_N = 100
def __init__(self, expr, var_start_end_x, var_start_end_y, label="", **kwargs):
super().__init__(**kwargs)
self.adaptive = kwargs.get("adaptive", False)
self.expr = expr
self._label = str(expr) if label is None else label
self._latex_label = latex(expr) if label is None else label
self.ranges = [var_start_end_x, var_start_end_y]
self.var_x, self.start_x, self.end_x = self.ranges[0]
self.var_y, self.start_y, self.end_y = self.ranges[1]
self._color = kwargs.get("color", kwargs.get("line_color", None))
if self.is_interactive and self.adaptive:
raise NotImplementedError("Interactive plot with `adaptive=True` "
"is not supported.")
# Check whether the depth is greater than 4 or less than 0.
depth = kwargs.get("depth", 0)
if depth > 4:
depth = 4
elif depth < 0:
depth = 0
self.depth = 4 + depth
self._post_init()
@property
def expr(self):
if self.adaptive:
return self._adaptive_expr
return self._non_adaptive_expr
@expr.setter
def expr(self, expr):
self._block_lambda_functions(expr)
# these are needed for adaptive evaluation
expr, has_equality = self._has_equality(sympify(expr))
self._adaptive_expr = expr
self.has_equality = has_equality
self._label = str(expr)
self._latex_label = latex(expr)
if isinstance(expr, (BooleanFunction, Ne)) and (not self.adaptive):
self.adaptive = True
msg = "contains Boolean functions. "
if isinstance(expr, Ne):
msg = "is an unequality. "
warnings.warn(
"The provided expression " + msg
+ "In order to plot the expression, the algorithm "
+ "automatically switched to an adaptive sampling."
)
if isinstance(expr, BooleanFunction):
self._non_adaptive_expr = None
self._is_equality = False
else:
# these are needed for uniform meshing evaluation
expr, is_equality = self._preprocess_meshgrid_expression(expr, self.adaptive)
self._non_adaptive_expr = expr
self._is_equality = is_equality
@property
def line_color(self):
return self._color
@line_color.setter
def line_color(self, v):
self._color = v
color = line_color
def _has_equality(self, expr):
# Represents whether the expression contains an Equality, GreaterThan
# or LessThan
has_equality = False
def arg_expand(bool_expr):
"""Recursively expands the arguments of an Boolean Function"""
for arg in bool_expr.args:
if isinstance(arg, BooleanFunction):
arg_expand(arg)
elif isinstance(arg, Relational):
arg_list.append(arg)
arg_list = []
if isinstance(expr, BooleanFunction):
arg_expand(expr)
# Check whether there is an equality in the expression provided.
if any(isinstance(e, (Equality, GreaterThan, LessThan)) for e in arg_list):
has_equality = True
elif not isinstance(expr, Relational):
expr = Equality(expr, 0)
has_equality = True
elif isinstance(expr, (Equality, GreaterThan, LessThan)):
has_equality = True
return expr, has_equality
def __str__(self):
f = lambda t: float(t) if len(t.free_symbols) == 0 else t
return self._str_helper(
"Implicit expression: %s for %s over %s and %s over %s") % (
str(self._adaptive_expr),
str(self.var_x),
str((f(self.start_x), f(self.end_x))),
str(self.var_y),
str((f(self.start_y), f(self.end_y))),
)
def get_data(self):
"""Returns numerical data.
Returns
=======
If the series is evaluated with the `adaptive=True` it returns:
interval_list : list
List of bounding rectangular intervals to be postprocessed and
eventually used with Matplotlib's ``fill`` command.
dummy : str
A string containing ``"fill"``.
Otherwise, it returns 2D numpy arrays to be used with Matplotlib's
``contour`` or ``contourf`` commands:
x_array : np.ndarray
y_array : np.ndarray
z_array : np.ndarray
plot_type : str
A string specifying which plot command to use, ``"contour"``
or ``"contourf"``.
"""
if self.adaptive:
data = self._adaptive_eval()
if data is not None:
return data
return self._get_meshes_grid()
def _adaptive_eval(self):
"""
References
==========
.. [1] Jeffrey Allen Tupper. Reliable Two-Dimensional Graphing Methods for
Mathematical Formulae with Two Free Variables.
.. [2] Jeffrey Allen Tupper. Graphing Equations with Generalized Interval
Arithmetic. Master's thesis. University of Toronto, 1996
"""
import sympy.plotting.intervalmath.lib_interval as li
user_functions = {}
printer = IntervalMathPrinter({
'fully_qualified_modules': False, 'inline': True,
'allow_unknown_functions': True,
'user_functions': user_functions})
keys = [t for t in dir(li) if ("__" not in t) and (t not in ["import_module", "interval"])]
vals = [getattr(li, k) for k in keys]
d = dict(zip(keys, vals))
func = lambdify((self.var_x, self.var_y), self.expr, modules=[d], printer=printer)
data = None
try:
data = self._get_raster_interval(func)
except NameError as err:
warnings.warn(
"Adaptive meshing could not be applied to the"
" expression, as some functions are not yet implemented"
" in the interval math module:\n\n"
"NameError: %s\n\n" % err +
"Proceeding with uniform meshing."
)
self.adaptive = False
except TypeError:
warnings.warn(
"Adaptive meshing could not be applied to the"
" expression. Using uniform meshing.")
self.adaptive = False
return data
def _get_raster_interval(self, func):
"""Uses interval math to adaptively mesh and obtain the plot"""
np = import_module('numpy')
k = self.depth
interval_list = []
sx, sy = [float(t) for t in [self.start_x, self.start_y]]
ex, ey = [float(t) for t in [self.end_x, self.end_y]]
# Create initial 32 divisions
xsample = np.linspace(sx, ex, 33)
ysample = np.linspace(sy, ey, 33)
# Add a small jitter so that there are no false positives for equality.
# Ex: y==x becomes True for x interval(1, 2) and y interval(1, 2)
# which will draw a rectangle.
jitterx = (
(np.random.rand(len(xsample)) * 2 - 1)
* (ex - sx)
/ 2 ** 20
)
jittery = (
(np.random.rand(len(ysample)) * 2 - 1)
* (ey - sy)
/ 2 ** 20
)
xsample += jitterx
ysample += jittery
xinter = [interval(x1, x2) for x1, x2 in zip(xsample[:-1], xsample[1:])]
yinter = [interval(y1, y2) for y1, y2 in zip(ysample[:-1], ysample[1:])]
interval_list = [[x, y] for x in xinter for y in yinter]
plot_list = []
# recursive call refinepixels which subdivides the intervals which are
# neither True nor False according to the expression.
def refine_pixels(interval_list):
"""Evaluates the intervals and subdivides the interval if the
expression is partially satisfied."""
temp_interval_list = []
plot_list = []
for intervals in interval_list:
# Convert the array indices to x and y values
intervalx = intervals[0]
intervaly = intervals[1]
func_eval = func(intervalx, intervaly)
# The expression is valid in the interval. Change the contour
# array values to 1.
if func_eval[1] is False or func_eval[0] is False:
pass
elif func_eval == (True, True):
plot_list.append([intervalx, intervaly])
elif func_eval[1] is None or func_eval[0] is None:
# Subdivide
avgx = intervalx.mid
avgy = intervaly.mid
a = interval(intervalx.start, avgx)
b = interval(avgx, intervalx.end)
c = interval(intervaly.start, avgy)
d = interval(avgy, intervaly.end)
temp_interval_list.append([a, c])
temp_interval_list.append([a, d])
temp_interval_list.append([b, c])
temp_interval_list.append([b, d])
return temp_interval_list, plot_list
while k >= 0 and len(interval_list):
interval_list, plot_list_temp = refine_pixels(interval_list)
plot_list.extend(plot_list_temp)
k = k - 1
# Check whether the expression represents an equality
# If it represents an equality, then none of the intervals
# would have satisfied the expression due to floating point
# differences. Add all the undecided values to the plot.
if self.has_equality:
for intervals in interval_list:
intervalx = intervals[0]
intervaly = intervals[1]
func_eval = func(intervalx, intervaly)
if func_eval[1] and func_eval[0] is not False:
plot_list.append([intervalx, intervaly])
return plot_list, "fill"
def _get_meshes_grid(self):
"""Generates the mesh for generating a contour.
In the case of equality, ``contour`` function of matplotlib can
be used. In other cases, matplotlib's ``contourf`` is used.
"""
np = import_module('numpy')
xarray, yarray, z_grid = self._evaluate()
_re, _im = np.real(z_grid), np.imag(z_grid)
_re[np.invert(np.isclose(_im, np.zeros_like(_im)))] = np.nan
if self._is_equality:
return xarray, yarray, _re, 'contour'
return xarray, yarray, _re, 'contourf'
@staticmethod
def _preprocess_meshgrid_expression(expr, adaptive):
"""If the expression is a Relational, rewrite it as a single
expression.
Returns
=======
expr : Expr
The rewritten expression
equality : Boolean
Wheter the original expression was an Equality or not.
"""
equality = False
if isinstance(expr, Equality):
expr = expr.lhs - expr.rhs
equality = True
elif isinstance(expr, Relational):
expr = expr.gts - expr.lts
elif not adaptive:
raise NotImplementedError(
"The expression is not supported for "
"plotting in uniform meshed plot."
)
return expr, equality
def get_label(self, use_latex=False, wrapper="$%s$"):
"""Return the label to be used to display the expression.
Parameters
==========
use_latex : bool
If False, the string representation of the expression is returned.
If True, the latex representation is returned.
wrapper : str
The backend might need the latex representation to be wrapped by
some characters. Default to ``"$%s$"``.
Returns
=======
label : str
"""
if use_latex is False:
return self._label
if self._label == str(self._adaptive_expr):
return self._get_wrapped_label(self._latex_label, wrapper)
return self._latex_label
##############################################################################
# Finding the centers of line segments or mesh faces
##############################################################################
def centers_of_segments(array):
np = import_module('numpy')
return np.mean(np.vstack((array[:-1], array[1:])), 0)
def centers_of_faces(array):
np = import_module('numpy')
return np.mean(np.dstack((array[:-1, :-1],
array[1:, :-1],
array[:-1, 1:],
array[:-1, :-1],
)), 2)
def flat(x, y, z, eps=1e-3):
"""Checks whether three points are almost collinear"""
np = import_module('numpy')
# Workaround plotting piecewise (#8577)
vector_a = (x - y).astype(float)
vector_b = (z - y).astype(float)
dot_product = np.dot(vector_a, vector_b)
vector_a_norm = np.linalg.norm(vector_a)
vector_b_norm = np.linalg.norm(vector_b)
cos_theta = dot_product / (vector_a_norm * vector_b_norm)
return abs(cos_theta + 1) < eps
def _set_discretization_points(kwargs, pt):
"""Allow the use of the keyword arguments ``n, n1, n2`` to
specify the number of discretization points in one and two
directions, while keeping back-compatibility with older keyword arguments
like, ``nb_of_points, nb_of_points_*, points``.
Parameters
==========
kwargs : dict
Dictionary of keyword arguments passed into a plotting function.
pt : type
The type of the series, which indicates the kind of plot we are
trying to create.
"""
replace_old_keywords = {
"nb_of_points": "n",
"nb_of_points_x": "n1",
"nb_of_points_y": "n2",
"nb_of_points_u": "n1",
"nb_of_points_v": "n2",
"points": "n"
}
for k, v in replace_old_keywords.items():
if k in kwargs.keys():
kwargs[v] = kwargs.pop(k)
if pt in [LineOver1DRangeSeries, Parametric2DLineSeries,
Parametric3DLineSeries]:
if "n" in kwargs.keys():
kwargs["n1"] = kwargs["n"]
if hasattr(kwargs["n"], "__iter__") and (len(kwargs["n"]) > 0):
kwargs["n1"] = kwargs["n"][0]
elif pt in [SurfaceOver2DRangeSeries, ContourSeries,
ParametricSurfaceSeries, ImplicitSeries]:
if "n" in kwargs.keys():
if hasattr(kwargs["n"], "__iter__") and (len(kwargs["n"]) > 1):
kwargs["n1"] = kwargs["n"][0]
kwargs["n2"] = kwargs["n"][1]
else:
kwargs["n1"] = kwargs["n2"] = kwargs["n"]
return kwargs
PK ]ZZZ i|� � sympy/plotting/textplot.pyfrom sympy.core.numbers import Float
from sympy.core.symbol import Dummy
from sympy.utilities.lambdify import lambdify
import math
def is_valid(x):
"""Check if a floating point number is valid"""
if x is None:
return False
if isinstance(x, complex):
return False
return not math.isinf(x) and not math.isnan(x)
def rescale(y, W, H, mi, ma):
"""Rescale the given array `y` to fit into the integer values
between `0` and `H-1` for the values between ``mi`` and ``ma``.
"""
y_new = []
norm = ma - mi
offset = (ma + mi) / 2
for x in range(W):
if is_valid(y[x]):
normalized = (y[x] - offset) / norm
if not is_valid(normalized):
y_new.append(None)
else:
rescaled = Float((normalized*H + H/2) * (H-1)/H).round()
rescaled = int(rescaled)
y_new.append(rescaled)
else:
y_new.append(None)
return y_new
def linspace(start, stop, num):
return [start + (stop - start) * x / (num-1) for x in range(num)]
def textplot_str(expr, a, b, W=55, H=21):
"""Generator for the lines of the plot"""
free = expr.free_symbols
if len(free) > 1:
raise ValueError(
"The expression must have a single variable. (Got {})"
.format(free))
x = free.pop() if free else Dummy()
f = lambdify([x], expr)
if isinstance(a, complex):
if a.imag == 0:
a = a.real
if isinstance(b, complex):
if b.imag == 0:
b = b.real
a = float(a)
b = float(b)
# Calculate function values
x = linspace(a, b, W)
y = []
for val in x:
try:
y.append(f(val))
# Not sure what exceptions to catch here or why...
except (ValueError, TypeError, ZeroDivisionError):
y.append(None)
# Normalize height to screen space
y_valid = list(filter(is_valid, y))
if y_valid:
ma = max(y_valid)
mi = min(y_valid)
if ma == mi:
if ma:
mi, ma = sorted([0, 2*ma])
else:
mi, ma = -1, 1
else:
mi, ma = -1, 1
y_range = ma - mi
precision = math.floor(math.log10(y_range)) - 1
precision *= -1
mi = round(mi, precision)
ma = round(ma, precision)
y = rescale(y, W, H, mi, ma)
y_bins = linspace(mi, ma, H)
# Draw plot
margin = 7
for h in range(H - 1, -1, -1):
s = [' '] * W
for i in range(W):
if y[i] == h:
if (i == 0 or y[i - 1] == h - 1) and (i == W - 1 or y[i + 1] == h + 1):
s[i] = '/'
elif (i == 0 or y[i - 1] == h + 1) and (i == W - 1 or y[i + 1] == h - 1):
s[i] = '\\'
else:
s[i] = '.'
if h == 0:
for i in range(W):
s[i] = '_'
# Print y values
if h in (0, H//2, H - 1):
prefix = ("%g" % y_bins[h]).rjust(margin)[:margin]
else:
prefix = " "*margin
s = "".join(s)
if h == H//2:
s = s.replace(" ", "-")
yield prefix + " |" + s
# Print x values
bottom = " " * (margin + 2)
bottom += ("%g" % x[0]).ljust(W//2)
if W % 2 == 1:
bottom += ("%g" % x[W//2]).ljust(W//2)
else:
bottom += ("%g" % x[W//2]).ljust(W//2-1)
bottom += "%g" % x[-1]
yield bottom
def textplot(expr, a, b, W=55, H=21):
r"""
Print a crude ASCII art plot of the SymPy expression 'expr' (which
should contain a single symbol, e.g. x or something else) over the
interval [a, b].
Examples
========
>>> from sympy import Symbol, sin
>>> from sympy.plotting import textplot
>>> t = Symbol('t')
>>> textplot(sin(t)*t, 0, 15)
14 | ...
| .
| .
| .
| .
| ...
| / . .
| /
| / .
| . . .
1.5 |----.......--------------------------------------------
|.... \ . .
| \ / .
| .. / .
| \ / .
| ....
| .
| . .
|
| . .
-11 |_______________________________________________________
0 7.5 15
"""
for line in textplot_str(expr, a, b, W, H):
print(line)
PK ]ZZZ c��/ �/ sympy/plotting/utils.pyfrom sympy.core.containers import Tuple
from sympy.core.basic import Basic
from sympy.core.expr import Expr
from sympy.core.function import AppliedUndef
from sympy.core.relational import Relational
from sympy.core.symbol import Dummy
from sympy.core.sympify import sympify
from sympy.logic.boolalg import BooleanFunction
from sympy.sets.fancysets import ImageSet
from sympy.sets.sets import FiniteSet
from sympy.tensor.indexed import Indexed
def _get_free_symbols(exprs):
"""Returns the free symbols of a symbolic expression.
If the expression contains any of these elements, assume that they are
the "free symbols" of the expression:
* indexed objects
* applied undefined function (useful for sympy.physics.mechanics module)
"""
if not isinstance(exprs, (list, tuple, set)):
exprs = [exprs]
if all(callable(e) for e in exprs):
return set()
free = set().union(*[e.atoms(Indexed) for e in exprs])
free = free.union(*[e.atoms(AppliedUndef) for e in exprs])
return free or set().union(*[e.free_symbols for e in exprs])
def extract_solution(set_sol, n=10):
"""Extract numerical solutions from a set solution (computed by solveset,
linsolve, nonlinsolve). Often, it is not trivial do get something useful
out of them.
Parameters
==========
n : int, optional
In order to replace ImageSet with FiniteSet, an iterator is created
for each ImageSet contained in `set_sol`, starting from 0 up to `n`.
Default value: 10.
"""
images = set_sol.find(ImageSet)
for im in images:
it = iter(im)
s = FiniteSet(*[next(it) for n in range(0, n)])
set_sol = set_sol.subs(im, s)
return set_sol
def _plot_sympify(args):
"""This function recursively loop over the arguments passed to the plot
functions: the sympify function will be applied to all arguments except
those of type string/dict.
Generally, users can provide the following arguments to a plot function:
expr, range1 [tuple, opt], ..., label [str, opt], rendering_kw [dict, opt]
`expr, range1, ...` can be sympified, whereas `label, rendering_kw` can't.
In particular, whenever a special character like $, {, }, ... is used in
the `label`, sympify will raise an error.
"""
if isinstance(args, Expr):
return args
args = list(args)
for i, a in enumerate(args):
if isinstance(a, (list, tuple)):
args[i] = Tuple(*_plot_sympify(a), sympify=False)
elif not (isinstance(a, (str, dict)) or callable(a)
# NOTE: check if it is a vector from sympy.physics.vector module
# without importing the module (because it slows down SymPy's
# import process and triggers SymPy's optional-dependencies
# tests to fail).
or ((a.__class__.__name__ == "Vector") and not isinstance(a, Basic))
):
args[i] = sympify(a)
return args
def _create_ranges(exprs, ranges, npar, label="", params=None):
"""This function does two things:
1. Check if the number of free symbols is in agreement with the type of
plot chosen. For example, plot() requires 1 free symbol;
plot3d() requires 2 free symbols.
2. Sometime users create plots without providing ranges for the variables.
Here we create the necessary ranges.
Parameters
==========
exprs : iterable
The expressions from which to extract the free symbols
ranges : iterable
The limiting ranges provided by the user
npar : int
The number of free symbols required by the plot functions.
For example,
npar=1 for plot, npar=2 for plot3d, ...
params : dict
A dictionary mapping symbols to parameters for interactive plot.
"""
get_default_range = lambda symbol: Tuple(symbol, -10, 10)
free_symbols = _get_free_symbols(exprs)
if params is not None:
free_symbols = free_symbols.difference(params.keys())
if len(free_symbols) > npar:
raise ValueError(
"Too many free symbols.\n"
+ "Expected {} free symbols.\n".format(npar)
+ "Received {}: {}".format(len(free_symbols), free_symbols)
)
if len(ranges) > npar:
raise ValueError(
"Too many ranges. Received %s, expected %s" % (len(ranges), npar))
# free symbols in the ranges provided by the user
rfs = set().union([r[0] for r in ranges])
if len(rfs) != len(ranges):
raise ValueError("Multiple ranges with the same symbol")
if len(ranges) < npar:
symbols = free_symbols.difference(rfs)
if symbols != set():
# add a range for each missing free symbols
for s in symbols:
ranges.append(get_default_range(s))
# if there is still room, fill them with dummys
for i in range(npar - len(ranges)):
ranges.append(get_default_range(Dummy()))
if len(free_symbols) == npar:
# there could be times when this condition is not met, for example
# plotting the function f(x, y) = x (which is a plane); in this case,
# free_symbols = {x} whereas rfs = {x, y} (or x and Dummy)
rfs = set().union([r[0] for r in ranges])
if len(free_symbols.difference(rfs)) > 0:
raise ValueError(
"Incompatible free symbols of the expressions with "
"the ranges.\n"
+ "Free symbols in the expressions: {}\n".format(free_symbols)
+ "Free symbols in the ranges: {}".format(rfs)
)
return ranges
def _is_range(r):
"""A range is defined as (symbol, start, end). start and end should
be numbers.
"""
# TODO: prange check goes here
return (
isinstance(r, Tuple)
and (len(r) == 3)
and (not isinstance(r.args[1], str)) and r.args[1].is_number
and (not isinstance(r.args[2], str)) and r.args[2].is_number
)
def _unpack_args(*args):
"""Given a list/tuple of arguments previously processed by _plot_sympify()
and/or _check_arguments(), separates and returns its components:
expressions, ranges, label and rendering keywords.
Examples
========
>>> from sympy import cos, sin, symbols
>>> from sympy.plotting.utils import _plot_sympify, _unpack_args
>>> x, y = symbols('x, y')
>>> args = (sin(x), (x, -10, 10), "f1")
>>> args = _plot_sympify(args)
>>> _unpack_args(*args)
([sin(x)], [(x, -10, 10)], 'f1', None)
>>> args = (sin(x**2 + y**2), (x, -2, 2), (y, -3, 3), "f2")
>>> args = _plot_sympify(args)
>>> _unpack_args(*args)
([sin(x**2 + y**2)], [(x, -2, 2), (y, -3, 3)], 'f2', None)
>>> args = (sin(x + y), cos(x - y), x + y, (x, -2, 2), (y, -3, 3), "f3")
>>> args = _plot_sympify(args)
>>> _unpack_args(*args)
([sin(x + y), cos(x - y), x + y], [(x, -2, 2), (y, -3, 3)], 'f3', None)
"""
ranges = [t for t in args if _is_range(t)]
labels = [t for t in args if isinstance(t, str)]
label = None if not labels else labels[0]
rendering_kw = [t for t in args if isinstance(t, dict)]
rendering_kw = None if not rendering_kw else rendering_kw[0]
# NOTE: why None? because args might have been preprocessed by
# _check_arguments, so None might represent the rendering_kw
results = [not (_is_range(a) or isinstance(a, (str, dict)) or (a is None)) for a in args]
exprs = [a for a, b in zip(args, results) if b]
return exprs, ranges, label, rendering_kw
def _check_arguments(args, nexpr, npar, **kwargs):
"""Checks the arguments and converts into tuples of the
form (exprs, ranges, label, rendering_kw).
Parameters
==========
args
The arguments provided to the plot functions
nexpr
The number of sub-expression forming an expression to be plotted.
For example:
nexpr=1 for plot.
nexpr=2 for plot_parametric: a curve is represented by a tuple of two
elements.
nexpr=1 for plot3d.
nexpr=3 for plot3d_parametric_line: a curve is represented by a tuple
of three elements.
npar
The number of free symbols required by the plot functions. For example,
npar=1 for plot, npar=2 for plot3d, ...
**kwargs :
keyword arguments passed to the plotting function. It will be used to
verify if ``params`` has ben provided.
Examples
========
.. plot::
:context: reset
:format: doctest
:include-source: True
>>> from sympy import cos, sin, symbols
>>> from sympy.plotting.plot import _check_arguments
>>> x = symbols('x')
>>> _check_arguments([cos(x), sin(x)], 2, 1)
[(cos(x), sin(x), (x, -10, 10), None, None)]
>>> _check_arguments([cos(x), sin(x), "test"], 2, 1)
[(cos(x), sin(x), (x, -10, 10), 'test', None)]
>>> _check_arguments([cos(x), sin(x), "test", {"a": 0, "b": 1}], 2, 1)
[(cos(x), sin(x), (x, -10, 10), 'test', {'a': 0, 'b': 1})]
>>> _check_arguments([x, x**2], 1, 1)
[(x, (x, -10, 10), None, None), (x**2, (x, -10, 10), None, None)]
"""
if not args:
return []
output = []
params = kwargs.get("params", None)
if all(isinstance(a, (Expr, Relational, BooleanFunction)) for a in args[:nexpr]):
# In this case, with a single plot command, we are plotting either:
# 1. one expression
# 2. multiple expressions over the same range
exprs, ranges, label, rendering_kw = _unpack_args(*args)
free_symbols = set().union(*[e.free_symbols for e in exprs])
ranges = _create_ranges(exprs, ranges, npar, label, params)
if nexpr > 1:
# in case of plot_parametric or plot3d_parametric_line, there will
# be 2 or 3 expressions defining a curve. Group them together.
if len(exprs) == nexpr:
exprs = (tuple(exprs),)
for expr in exprs:
# need this if-else to deal with both plot/plot3d and
# plot_parametric/plot3d_parametric_line
is_expr = isinstance(expr, (Expr, Relational, BooleanFunction))
e = (expr,) if is_expr else expr
output.append((*e, *ranges, label, rendering_kw))
else:
# In this case, we are plotting multiple expressions, each one with its
# range. Each "expression" to be plotted has the following form:
# (expr, range, label) where label is optional
_, ranges, labels, rendering_kw = _unpack_args(*args)
labels = [labels] if labels else []
# number of expressions
n = (len(ranges) + len(labels) +
(len(rendering_kw) if rendering_kw is not None else 0))
new_args = args[:-n] if n > 0 else args
# at this point, new_args might just be [expr]. But I need it to be
# [[expr]] in order to be able to loop over
# [expr, range [opt], label [opt]]
if not isinstance(new_args[0], (list, tuple, Tuple)):
new_args = [new_args]
# Each arg has the form (expr1, expr2, ..., range1 [optional], ...,
# label [optional], rendering_kw [optional])
for arg in new_args:
# look for "local" range and label. If there is not, use "global".
l = [a for a in arg if isinstance(a, str)]
if not l:
l = labels
r = [a for a in arg if _is_range(a)]
if not r:
r = ranges.copy()
rend_kw = [a for a in arg if isinstance(a, dict)]
rend_kw = rendering_kw if len(rend_kw) == 0 else rend_kw[0]
# NOTE: arg = arg[:nexpr] may raise an exception if lambda
# functions are used. Execute the following instead:
arg = [arg[i] for i in range(nexpr)]
free_symbols = set()
if all(not callable(a) for a in arg):
free_symbols = free_symbols.union(*[a.free_symbols for a in arg])
if len(r) != npar:
r = _create_ranges(arg, r, npar, "", params)
label = None if not l else l[0]
output.append((*arg, *r, label, rend_kw))
return output
PK ]ZZZ # sympy/plotting/backends/__init__.pyPK ]ZZZ��e�?: ?: ' sympy/plotting/backends/base_backend.pyfrom sympy.plotting.series import BaseSeries, GenericDataSeries
from sympy.utilities.exceptions import sympy_deprecation_warning
from sympy.utilities.iterables import is_sequence
__doctest_requires__ = {
('Plot.append', 'Plot.extend'): ['matplotlib'],
}
# Global variable
# Set to False when running tests / doctests so that the plots don't show.
_show = True
def unset_show():
"""
Disable show(). For use in the tests.
"""
global _show
_show = False
def _deprecation_msg_m_a_r_f(attr):
sympy_deprecation_warning(
f"The `{attr}` property is deprecated. The `{attr}` keyword "
"argument should be passed to a plotting function, which generates "
"the appropriate data series. If needed, index the plot object to "
"retrieve a specific data series.",
deprecated_since_version="1.13",
active_deprecations_target="deprecated-markers-annotations-fill-rectangles",
stacklevel=4)
def _create_generic_data_series(**kwargs):
keywords = ["annotations", "markers", "fill", "rectangles"]
series = []
for kw in keywords:
dictionaries = kwargs.pop(kw, [])
if dictionaries is None:
dictionaries = []
if isinstance(dictionaries, dict):
dictionaries = [dictionaries]
for d in dictionaries:
args = d.pop("args", [])
series.append(GenericDataSeries(kw, *args, **d))
return series
class Plot:
"""Base class for all backends. A backend represents the plotting library,
which implements the necessary functionalities in order to use SymPy
plotting functions.
For interactive work the function :func:`plot` is better suited.
This class permits the plotting of SymPy expressions using numerous
backends (:external:mod:`matplotlib`, textplot, the old pyglet module for SymPy, Google
charts api, etc).
The figure can contain an arbitrary number of plots of SymPy expressions,
lists of coordinates of points, etc. Plot has a private attribute _series that
contains all data series to be plotted (expressions for lines or surfaces,
lists of points, etc (all subclasses of BaseSeries)). Those data series are
instances of classes not imported by ``from sympy import *``.
The customization of the figure is on two levels. Global options that
concern the figure as a whole (e.g. title, xlabel, scale, etc) and
per-data series options (e.g. name) and aesthetics (e.g. color, point shape,
line type, etc.).
The difference between options and aesthetics is that an aesthetic can be
a function of the coordinates (or parameters in a parametric plot). The
supported values for an aesthetic are:
- None (the backend uses default values)
- a constant
- a function of one variable (the first coordinate or parameter)
- a function of two variables (the first and second coordinate or parameters)
- a function of three variables (only in nonparametric 3D plots)
Their implementation depends on the backend so they may not work in some
backends.
If the plot is parametric and the arity of the aesthetic function permits
it the aesthetic is calculated over parameters and not over coordinates.
If the arity does not permit calculation over parameters the calculation is
done over coordinates.
Only cartesian coordinates are supported for the moment, but you can use
the parametric plots to plot in polar, spherical and cylindrical
coordinates.
The arguments for the constructor Plot must be subclasses of BaseSeries.
Any global option can be specified as a keyword argument.
The global options for a figure are:
- title : str
- xlabel : str or Symbol
- ylabel : str or Symbol
- zlabel : str or Symbol
- legend : bool
- xscale : {'linear', 'log'}
- yscale : {'linear', 'log'}
- axis : bool
- axis_center : tuple of two floats or {'center', 'auto'}
- xlim : tuple of two floats
- ylim : tuple of two floats
- aspect_ratio : tuple of two floats or {'auto'}
- autoscale : bool
- margin : float in [0, 1]
- backend : {'default', 'matplotlib', 'text'} or a subclass of BaseBackend
- size : optional tuple of two floats, (width, height); default: None
The per data series options and aesthetics are:
There are none in the base series. See below for options for subclasses.
Some data series support additional aesthetics or options:
:class:`~.LineOver1DRangeSeries`, :class:`~.Parametric2DLineSeries`, and
:class:`~.Parametric3DLineSeries` support the following:
Aesthetics:
- line_color : string, or float, or function, optional
Specifies the color for the plot, which depends on the backend being
used.
For example, if ``MatplotlibBackend`` is being used, then
Matplotlib string colors are acceptable (``"red"``, ``"r"``,
``"cyan"``, ``"c"``, ...).
Alternatively, we can use a float number, 0 < color < 1, wrapped in a
string (for example, ``line_color="0.5"``) to specify grayscale colors.
Alternatively, We can specify a function returning a single
float value: this will be used to apply a color-loop (for example,
``line_color=lambda x: math.cos(x)``).
Note that by setting line_color, it would be applied simultaneously
to all the series.
Options:
- label : str
- steps : bool
- integers_only : bool
:class:`~.SurfaceOver2DRangeSeries` and :class:`~.ParametricSurfaceSeries`
support the following:
Aesthetics:
- surface_color : function which returns a float.
Notes
=====
How the plotting module works:
1. Whenever a plotting function is called, the provided expressions are
processed and a list of instances of the
:class:`~sympy.plotting.series.BaseSeries` class is created, containing
the necessary information to plot the expressions
(e.g. the expression, ranges, series name, ...). Eventually, these
objects will generate the numerical data to be plotted.
2. A subclass of :class:`~.Plot` class is instantiaed (referred to as
backend, from now on), which stores the list of series and the main
attributes of the plot (e.g. axis labels, title, ...).
The backend implements the logic to generate the actual figure with
some plotting library.
3. When the ``show`` command is executed, series are processed one by one
to generate numerical data and add it to the figure. The backend is also
going to set the axis labels, title, ..., according to the values stored
in the Plot instance.
The backend should check if it supports the data series that it is given
(e.g. :class:`TextBackend` supports only
:class:`~sympy.plotting.series.LineOver1DRangeSeries`).
It is the backend responsibility to know how to use the class of data series
that it's given. Note that the current implementation of the ``*Series``
classes is "matplotlib-centric": the numerical data returned by the
``get_points`` and ``get_meshes`` methods is meant to be used directly by
Matplotlib. Therefore, the new backend will have to pre-process the
numerical data to make it compatible with the chosen plotting library.
Keep in mind that future SymPy versions may improve the ``*Series`` classes
in order to return numerical data "non-matplotlib-centric", hence if you code
a new backend you have the responsibility to check if its working on each
SymPy release.
Please explore the :class:`MatplotlibBackend` source code to understand
how a backend should be coded.
In order to be used by SymPy plotting functions, a backend must implement
the following methods:
* show(self): used to loop over the data series, generate the numerical
data, plot it and set the axis labels, title, ...
* save(self, path): used to save the current plot to the specified file
path.
* close(self): used to close the current plot backend (note: some plotting
library does not support this functionality. In that case, just raise a
warning).
"""
def __init__(self, *args,
title=None, xlabel=None, ylabel=None, zlabel=None, aspect_ratio='auto',
xlim=None, ylim=None, axis_center='auto', axis=True,
xscale='linear', yscale='linear', legend=False, autoscale=True,
margin=0, annotations=None, markers=None, rectangles=None,
fill=None, backend='default', size=None, **kwargs):
# Options for the graph as a whole.
# The possible values for each option are described in the docstring of
# Plot. They are based purely on convention, no checking is done.
self.title = title
self.xlabel = xlabel
self.ylabel = ylabel
self.zlabel = zlabel
self.aspect_ratio = aspect_ratio
self.axis_center = axis_center
self.axis = axis
self.xscale = xscale
self.yscale = yscale
self.legend = legend
self.autoscale = autoscale
self.margin = margin
self._annotations = annotations
self._markers = markers
self._rectangles = rectangles
self._fill = fill
# Contains the data objects to be plotted. The backend should be smart
# enough to iterate over this list.
self._series = []
self._series.extend(args)
self._series.extend(_create_generic_data_series(
annotations=annotations, markers=markers, rectangles=rectangles,
fill=fill))
is_real = \
lambda lim: all(getattr(i, 'is_real', True) for i in lim)
is_finite = \
lambda lim: all(getattr(i, 'is_finite', True) for i in lim)
# reduce code repetition
def check_and_set(t_name, t):
if t:
if not is_real(t):
raise ValueError(
"All numbers from {}={} must be real".format(t_name, t))
if not is_finite(t):
raise ValueError(
"All numbers from {}={} must be finite".format(t_name, t))
setattr(self, t_name, (float(t[0]), float(t[1])))
self.xlim = None
check_and_set("xlim", xlim)
self.ylim = None
check_and_set("ylim", ylim)
self.size = None
check_and_set("size", size)
@property
def _backend(self):
return self
@property
def backend(self):
return type(self)
def __str__(self):
series_strs = [('[%d]: ' % i) + str(s)
for i, s in enumerate(self._series)]
return 'Plot object containing:\n' + '\n'.join(series_strs)
def __getitem__(self, index):
return self._series[index]
def __setitem__(self, index, *args):
if len(args) == 1 and isinstance(args[0], BaseSeries):
self._series[index] = args
def __delitem__(self, index):
del self._series[index]
def append(self, arg):
"""Adds an element from a plot's series to an existing plot.
Examples
========
Consider two ``Plot`` objects, ``p1`` and ``p2``. To add the
second plot's first series object to the first, use the
``append`` method, like so:
.. plot::
:format: doctest
:include-source: True
>>> from sympy import symbols
>>> from sympy.plotting import plot
>>> x = symbols('x')
>>> p1 = plot(x*x, show=False)
>>> p2 = plot(x, show=False)
>>> p1.append(p2[0])
>>> p1
Plot object containing:
[0]: cartesian line: x**2 for x over (-10.0, 10.0)
[1]: cartesian line: x for x over (-10.0, 10.0)
>>> p1.show()
See Also
========
extend
"""
if isinstance(arg, BaseSeries):
self._series.append(arg)
else:
raise TypeError('Must specify element of plot to append.')
def extend(self, arg):
"""Adds all series from another plot.
Examples
========
Consider two ``Plot`` objects, ``p1`` and ``p2``. To add the
second plot to the first, use the ``extend`` method, like so:
.. plot::
:format: doctest
:include-source: True
>>> from sympy import symbols
>>> from sympy.plotting import plot
>>> x = symbols('x')
>>> p1 = plot(x**2, show=False)
>>> p2 = plot(x, -x, show=False)
>>> p1.extend(p2)
>>> p1
Plot object containing:
[0]: cartesian line: x**2 for x over (-10.0, 10.0)
[1]: cartesian line: x for x over (-10.0, 10.0)
[2]: cartesian line: -x for x over (-10.0, 10.0)
>>> p1.show()
"""
if isinstance(arg, Plot):
self._series.extend(arg._series)
elif is_sequence(arg):
self._series.extend(arg)
else:
raise TypeError('Expecting Plot or sequence of BaseSeries')
def show(self):
raise NotImplementedError
def save(self, path):
raise NotImplementedError
def close(self):
raise NotImplementedError
# deprecations
@property
def markers(self):
""".. deprecated:: 1.13"""
_deprecation_msg_m_a_r_f("markers")
return self._markers
@markers.setter
def markers(self, v):
""".. deprecated:: 1.13"""
_deprecation_msg_m_a_r_f("markers")
self._series.extend(_create_generic_data_series(markers=v))
self._markers = v
@property
def annotations(self):
""".. deprecated:: 1.13"""
_deprecation_msg_m_a_r_f("annotations")
return self._annotations
@annotations.setter
def annotations(self, v):
""".. deprecated:: 1.13"""
_deprecation_msg_m_a_r_f("annotations")
self._series.extend(_create_generic_data_series(annotations=v))
self._annotations = v
@property
def rectangles(self):
""".. deprecated:: 1.13"""
_deprecation_msg_m_a_r_f("rectangles")
return self._rectangles
@rectangles.setter
def rectangles(self, v):
""".. deprecated:: 1.13"""
_deprecation_msg_m_a_r_f("rectangles")
self._series.extend(_create_generic_data_series(rectangles=v))
self._rectangles = v
@property
def fill(self):
""".. deprecated:: 1.13"""
_deprecation_msg_m_a_r_f("fill")
return self._fill
@fill.setter
def fill(self, v):
""".. deprecated:: 1.13"""
_deprecation_msg_m_a_r_f("fill")
self._series.extend(_create_generic_data_series(fill=v))
self._fill = v
PK ]ZZZ�x5� � 5 sympy/plotting/backends/matplotlibbackend/__init__.pyfrom sympy.plotting.backends.matplotlibbackend.matplotlib import (
MatplotlibBackend, _matplotlib_list
)
__all__ = ["MatplotlibBackend", "_matplotlib_list"]
PK ]ZZZYd1 1 7 sympy/plotting/backends/matplotlibbackend/matplotlib.pyfrom collections.abc import Callable
from sympy.core.basic import Basic
from sympy.external import import_module
import sympy.plotting.backends.base_backend as base_backend
from sympy.printing.latex import latex
# N.B.
# When changing the minimum module version for matplotlib, please change
# the same in the `SymPyDocTestFinder`` in `sympy/testing/runtests.py`
def _str_or_latex(label):
if isinstance(label, Basic):
return latex(label, mode='inline')
return str(label)
def _matplotlib_list(interval_list):
"""
Returns lists for matplotlib ``fill`` command from a list of bounding
rectangular intervals
"""
xlist = []
ylist = []
if len(interval_list):
for intervals in interval_list:
intervalx = intervals[0]
intervaly = intervals[1]
xlist.extend([intervalx.start, intervalx.start,
intervalx.end, intervalx.end, None])
ylist.extend([intervaly.start, intervaly.end,
intervaly.end, intervaly.start, None])
else:
#XXX Ugly hack. Matplotlib does not accept empty lists for ``fill``
xlist.extend((None, None, None, None))
ylist.extend((None, None, None, None))
return xlist, ylist
# Don't have to check for the success of importing matplotlib in each case;
# we will only be using this backend if we can successfully import matploblib
class MatplotlibBackend(base_backend.Plot):
""" This class implements the functionalities to use Matplotlib with SymPy
plotting functions.
"""
def __init__(self, *series, **kwargs):
super().__init__(*series, **kwargs)
self.matplotlib = import_module('matplotlib',
import_kwargs={'fromlist': ['pyplot', 'cm', 'collections']},
min_module_version='1.1.0', catch=(RuntimeError,))
self.plt = self.matplotlib.pyplot
self.cm = self.matplotlib.cm
self.LineCollection = self.matplotlib.collections.LineCollection
self.aspect = kwargs.get('aspect_ratio', 'auto')
if self.aspect != 'auto':
self.aspect = float(self.aspect[1]) / self.aspect[0]
# PlotGrid can provide its figure and axes to be populated with
# the data from the series.
self._plotgrid_fig = kwargs.pop("fig", None)
self._plotgrid_ax = kwargs.pop("ax", None)
def _create_figure(self):
def set_spines(ax):
ax.spines['left'].set_position('zero')
ax.spines['right'].set_color('none')
ax.spines['bottom'].set_position('zero')
ax.spines['top'].set_color('none')
ax.xaxis.set_ticks_position('bottom')
ax.yaxis.set_ticks_position('left')
if self._plotgrid_fig is not None:
self.fig = self._plotgrid_fig
self.ax = self._plotgrid_ax
if not any(s.is_3D for s in self._series):
set_spines(self.ax)
else:
self.fig = self.plt.figure(figsize=self.size)
if any(s.is_3D for s in self._series):
self.ax = self.fig.add_subplot(1, 1, 1, projection="3d")
else:
self.ax = self.fig.add_subplot(1, 1, 1)
set_spines(self.ax)
@staticmethod
def get_segments(x, y, z=None):
""" Convert two list of coordinates to a list of segments to be used
with Matplotlib's :external:class:`~matplotlib.collections.LineCollection`.
Parameters
==========
x : list
List of x-coordinates
y : list
List of y-coordinates
z : list
List of z-coordinates for a 3D line.
"""
np = import_module('numpy')
if z is not None:
dim = 3
points = (x, y, z)
else:
dim = 2
points = (x, y)
points = np.ma.array(points).T.reshape(-1, 1, dim)
return np.ma.concatenate([points[:-1], points[1:]], axis=1)
def _process_series(self, series, ax):
np = import_module('numpy')
mpl_toolkits = import_module(
'mpl_toolkits', import_kwargs={'fromlist': ['mplot3d']})
# XXX Workaround for matplotlib issue
# https://github.com/matplotlib/matplotlib/issues/17130
xlims, ylims, zlims = [], [], []
for s in series:
# Create the collections
if s.is_2Dline:
if s.is_parametric:
x, y, param = s.get_data()
else:
x, y = s.get_data()
if (isinstance(s.line_color, (int, float)) or
callable(s.line_color)):
segments = self.get_segments(x, y)
collection = self.LineCollection(segments)
collection.set_array(s.get_color_array())
ax.add_collection(collection)
else:
lbl = _str_or_latex(s.label)
line, = ax.plot(x, y, label=lbl, color=s.line_color)
elif s.is_contour:
ax.contour(*s.get_data())
elif s.is_3Dline:
x, y, z, param = s.get_data()
if (isinstance(s.line_color, (int, float)) or
callable(s.line_color)):
art3d = mpl_toolkits.mplot3d.art3d
segments = self.get_segments(x, y, z)
collection = art3d.Line3DCollection(segments)
collection.set_array(s.get_color_array())
ax.add_collection(collection)
else:
lbl = _str_or_latex(s.label)
ax.plot(x, y, z, label=lbl, color=s.line_color)
xlims.append(s._xlim)
ylims.append(s._ylim)
zlims.append(s._zlim)
elif s.is_3Dsurface:
if s.is_parametric:
x, y, z, u, v = s.get_data()
else:
x, y, z = s.get_data()
collection = ax.plot_surface(x, y, z,
cmap=getattr(self.cm, 'viridis', self.cm.jet),
rstride=1, cstride=1, linewidth=0.1)
if isinstance(s.surface_color, (float, int, Callable)):
color_array = s.get_color_array()
color_array = color_array.reshape(color_array.size)
collection.set_array(color_array)
else:
collection.set_color(s.surface_color)
xlims.append(s._xlim)
ylims.append(s._ylim)
zlims.append(s._zlim)
elif s.is_implicit:
points = s.get_data()
if len(points) == 2:
# interval math plotting
x, y = _matplotlib_list(points[0])
ax.fill(x, y, facecolor=s.line_color, edgecolor='None')
else:
# use contourf or contour depending on whether it is
# an inequality or equality.
# XXX: ``contour`` plots multiple lines. Should be fixed.
ListedColormap = self.matplotlib.colors.ListedColormap
colormap = ListedColormap(["white", s.line_color])
xarray, yarray, zarray, plot_type = points
if plot_type == 'contour':
ax.contour(xarray, yarray, zarray, cmap=colormap)
else:
ax.contourf(xarray, yarray, zarray, cmap=colormap)
elif s.is_generic:
if s.type == "markers":
# s.rendering_kw["color"] = s.line_color
ax.plot(*s.args, **s.rendering_kw)
elif s.type == "annotations":
ax.annotate(*s.args, **s.rendering_kw)
elif s.type == "fill":
# s.rendering_kw["color"] = s.line_color
ax.fill_between(*s.args, **s.rendering_kw)
elif s.type == "rectangles":
# s.rendering_kw["color"] = s.line_color
ax.add_patch(
self.matplotlib.patches.Rectangle(
*s.args, **s.rendering_kw))
else:
raise NotImplementedError(
'{} is not supported in the SymPy plotting module '
'with matplotlib backend. Please report this issue.'
.format(ax))
Axes3D = mpl_toolkits.mplot3d.Axes3D
if not isinstance(ax, Axes3D):
ax.autoscale_view(
scalex=ax.get_autoscalex_on(),
scaley=ax.get_autoscaley_on())
else:
# XXX Workaround for matplotlib issue
# https://github.com/matplotlib/matplotlib/issues/17130
if xlims:
xlims = np.array(xlims)
xlim = (np.amin(xlims[:, 0]), np.amax(xlims[:, 1]))
ax.set_xlim(xlim)
else:
ax.set_xlim([0, 1])
if ylims:
ylims = np.array(ylims)
ylim = (np.amin(ylims[:, 0]), np.amax(ylims[:, 1]))
ax.set_ylim(ylim)
else:
ax.set_ylim([0, 1])
if zlims:
zlims = np.array(zlims)
zlim = (np.amin(zlims[:, 0]), np.amax(zlims[:, 1]))
ax.set_zlim(zlim)
else:
ax.set_zlim([0, 1])
# Set global options.
# TODO The 3D stuff
# XXX The order of those is important.
if self.xscale and not isinstance(ax, Axes3D):
ax.set_xscale(self.xscale)
if self.yscale and not isinstance(ax, Axes3D):
ax.set_yscale(self.yscale)
if not isinstance(ax, Axes3D) or self.matplotlib.__version__ >= '1.2.0': # XXX in the distant future remove this check
ax.set_autoscale_on(self.autoscale)
if self.axis_center:
val = self.axis_center
if isinstance(ax, Axes3D):
pass
elif val == 'center':
ax.spines['left'].set_position('center')
ax.spines['bottom'].set_position('center')
elif val == 'auto':
xl, xh = ax.get_xlim()
yl, yh = ax.get_ylim()
pos_left = ('data', 0) if xl*xh <= 0 else 'center'
pos_bottom = ('data', 0) if yl*yh <= 0 else 'center'
ax.spines['left'].set_position(pos_left)
ax.spines['bottom'].set_position(pos_bottom)
else:
ax.spines['left'].set_position(('data', val[0]))
ax.spines['bottom'].set_position(('data', val[1]))
if not self.axis:
ax.set_axis_off()
if self.legend:
if ax.legend():
ax.legend_.set_visible(self.legend)
if self.margin:
ax.set_xmargin(self.margin)
ax.set_ymargin(self.margin)
if self.title:
ax.set_title(self.title)
if self.xlabel:
xlbl = _str_or_latex(self.xlabel)
ax.set_xlabel(xlbl, position=(1, 0))
if self.ylabel:
ylbl = _str_or_latex(self.ylabel)
ax.set_ylabel(ylbl, position=(0, 1))
if isinstance(ax, Axes3D) and self.zlabel:
zlbl = _str_or_latex(self.zlabel)
ax.set_zlabel(zlbl, position=(0, 1))
# xlim and ylim should always be set at last so that plot limits
# doesn't get altered during the process.
if self.xlim:
ax.set_xlim(self.xlim)
if self.ylim:
ax.set_ylim(self.ylim)
self.ax.set_aspect(self.aspect)
def process_series(self):
"""
Iterates over every ``Plot`` object and further calls
_process_series()
"""
self._create_figure()
self._process_series(self._series, self.ax)
def show(self):
self.process_series()
#TODO after fixing https://github.com/ipython/ipython/issues/1255
# you can uncomment the next line and remove the pyplot.show() call
#self.fig.show()
if base_backend._show:
self.fig.tight_layout()
self.plt.show()
else:
self.close()
def save(self, path):
self.process_series()
self.fig.savefig(path)
def close(self):
self.plt.close(self.fig)
PK ]ZZZ��Eu\ \ / sympy/plotting/backends/textbackend/__init__.pyfrom sympy.plotting.backends.textbackend.text import TextBackend
__all__ = ["TextBackend"]
PK ]ZZZ�/# # + sympy/plotting/backends/textbackend/text.pyimport sympy.plotting.backends.base_backend as base_backend
from sympy.plotting.series import LineOver1DRangeSeries
from sympy.plotting.textplot import textplot
class TextBackend(base_backend.Plot):
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
def show(self):
if not base_backend._show:
return
if len(self._series) != 1:
raise ValueError(
'The TextBackend supports only one graph per Plot.')
elif not isinstance(self._series[0], LineOver1DRangeSeries):
raise ValueError(
'The TextBackend supports only expressions over a 1D range')
else:
ser = self._series[0]
textplot(ser.expr, ser.start, ser.end)
def close(self):
pass
PK ]ZZZF ��� � ' sympy/plotting/intervalmath/__init__.pyfrom .interval_arithmetic import interval
from .lib_interval import (Abs, exp, log, log10, sin, cos, tan, sqrt,
imin, imax, sinh, cosh, tanh, acosh, asinh, atanh,
asin, acos, atan, ceil, floor, And, Or)
__all__ = [
'interval',
'Abs', 'exp', 'log', 'log10', 'sin', 'cos', 'tan', 'sqrt', 'imin', 'imax',
'sinh', 'cosh', 'tanh', 'acosh', 'asinh', 'atanh', 'asin', 'acos', 'atan',
'ceil', 'floor', 'And', 'Or',
]
PK ]ZZZ ����< �< 2 sympy/plotting/intervalmath/interval_arithmetic.py"""
Interval Arithmetic for plotting.
This module does not implement interval arithmetic accurately and
hence cannot be used for purposes other than plotting. If you want
to use interval arithmetic, use mpmath's interval arithmetic.
The module implements interval arithmetic using numpy and
python floating points. The rounding up and down is not handled
and hence this is not an accurate implementation of interval
arithmetic.
The module uses numpy for speed which cannot be achieved with mpmath.
"""
# Q: Why use numpy? Why not simply use mpmath's interval arithmetic?
# A: mpmath's interval arithmetic simulates a floating point unit
# and hence is slow, while numpy evaluations are orders of magnitude
# faster.
# Q: Why create a separate class for intervals? Why not use SymPy's
# Interval Sets?
# A: The functionalities that will be required for plotting is quite
# different from what Interval Sets implement.
# Q: Why is rounding up and down according to IEEE754 not handled?
# A: It is not possible to do it in both numpy and python. An external
# library has to used, which defeats the whole purpose i.e., speed. Also
# rounding is handled for very few functions in those libraries.
# Q Will my plots be affected?
# A It will not affect most of the plots. The interval arithmetic
# module based suffers the same problems as that of floating point
# arithmetic.
from sympy.core.numbers import int_valued
from sympy.core.logic import fuzzy_and
from sympy.simplify.simplify import nsimplify
from .interval_membership import intervalMembership
class interval:
""" Represents an interval containing floating points as start and
end of the interval
The is_valid variable tracks whether the interval obtained as the
result of the function is in the domain and is continuous.
- True: Represents the interval result of a function is continuous and
in the domain of the function.
- False: The interval argument of the function was not in the domain of
the function, hence the is_valid of the result interval is False
- None: The function was not continuous over the interval or
the function's argument interval is partly in the domain of the
function
A comparison between an interval and a real number, or a
comparison between two intervals may return ``intervalMembership``
of two 3-valued logic values.
"""
def __init__(self, *args, is_valid=True, **kwargs):
self.is_valid = is_valid
if len(args) == 1:
if isinstance(args[0], interval):
self.start, self.end = args[0].start, args[0].end
else:
self.start = float(args[0])
self.end = float(args[0])
elif len(args) == 2:
if args[0] < args[1]:
self.start = float(args[0])
self.end = float(args[1])
else:
self.start = float(args[1])
self.end = float(args[0])
else:
raise ValueError("interval takes a maximum of two float values "
"as arguments")
@property
def mid(self):
return (self.start + self.end) / 2.0
@property
def width(self):
return self.end - self.start
def __repr__(self):
return "interval(%f, %f)" % (self.start, self.end)
def __str__(self):
return "[%f, %f]" % (self.start, self.end)
def __lt__(self, other):
if isinstance(other, (int, float)):
if self.end < other:
return intervalMembership(True, self.is_valid)
elif self.start > other:
return intervalMembership(False, self.is_valid)
else:
return intervalMembership(None, self.is_valid)
elif isinstance(other, interval):
valid = fuzzy_and([self.is_valid, other.is_valid])
if self.end < other. start:
return intervalMembership(True, valid)
if self.start > other.end:
return intervalMembership(False, valid)
return intervalMembership(None, valid)
else:
return NotImplemented
def __gt__(self, other):
if isinstance(other, (int, float)):
if self.start > other:
return intervalMembership(True, self.is_valid)
elif self.end < other:
return intervalMembership(False, self.is_valid)
else:
return intervalMembership(None, self.is_valid)
elif isinstance(other, interval):
return other.__lt__(self)
else:
return NotImplemented
def __eq__(self, other):
if isinstance(other, (int, float)):
if self.start == other and self.end == other:
return intervalMembership(True, self.is_valid)
if other in self:
return intervalMembership(None, self.is_valid)
else:
return intervalMembership(False, self.is_valid)
if isinstance(other, interval):
valid = fuzzy_and([self.is_valid, other.is_valid])
if self.start == other.start and self.end == other.end:
return intervalMembership(True, valid)
elif self.__lt__(other)[0] is not None:
return intervalMembership(False, valid)
else:
return intervalMembership(None, valid)
else:
return NotImplemented
def __ne__(self, other):
if isinstance(other, (int, float)):
if self.start == other and self.end == other:
return intervalMembership(False, self.is_valid)
if other in self:
return intervalMembership(None, self.is_valid)
else:
return intervalMembership(True, self.is_valid)
if isinstance(other, interval):
valid = fuzzy_and([self.is_valid, other.is_valid])
if self.start == other.start and self.end == other.end:
return intervalMembership(False, valid)
if not self.__lt__(other)[0] is None:
return intervalMembership(True, valid)
return intervalMembership(None, valid)
else:
return NotImplemented
def __le__(self, other):
if isinstance(other, (int, float)):
if self.end <= other:
return intervalMembership(True, self.is_valid)
if self.start > other:
return intervalMembership(False, self.is_valid)
else:
return intervalMembership(None, self.is_valid)
if isinstance(other, interval):
valid = fuzzy_and([self.is_valid, other.is_valid])
if self.end <= other.start:
return intervalMembership(True, valid)
if self.start > other.end:
return intervalMembership(False, valid)
return intervalMembership(None, valid)
else:
return NotImplemented
def __ge__(self, other):
if isinstance(other, (int, float)):
if self.start >= other:
return intervalMembership(True, self.is_valid)
elif self.end < other:
return intervalMembership(False, self.is_valid)
else:
return intervalMembership(None, self.is_valid)
elif isinstance(other, interval):
return other.__le__(self)
def __add__(self, other):
if isinstance(other, (int, float)):
if self.is_valid:
return interval(self.start + other, self.end + other)
else:
start = self.start + other
end = self.end + other
return interval(start, end, is_valid=self.is_valid)
elif isinstance(other, interval):
start = self.start + other.start
end = self.end + other.end
valid = fuzzy_and([self.is_valid, other.is_valid])
return interval(start, end, is_valid=valid)
else:
return NotImplemented
__radd__ = __add__
def __sub__(self, other):
if isinstance(other, (int, float)):
start = self.start - other
end = self.end - other
return interval(start, end, is_valid=self.is_valid)
elif isinstance(other, interval):
start = self.start - other.end
end = self.end - other.start
valid = fuzzy_and([self.is_valid, other.is_valid])
return interval(start, end, is_valid=valid)
else:
return NotImplemented
def __rsub__(self, other):
if isinstance(other, (int, float)):
start = other - self.end
end = other - self.start
return interval(start, end, is_valid=self.is_valid)
elif isinstance(other, interval):
return other.__sub__(self)
else:
return NotImplemented
def __neg__(self):
if self.is_valid:
return interval(-self.end, -self.start)
else:
return interval(-self.end, -self.start, is_valid=self.is_valid)
def __mul__(self, other):
if isinstance(other, interval):
if self.is_valid is False or other.is_valid is False:
return interval(-float('inf'), float('inf'), is_valid=False)
elif self.is_valid is None or other.is_valid is None:
return interval(-float('inf'), float('inf'), is_valid=None)
else:
inters = []
inters.append(self.start * other.start)
inters.append(self.end * other.start)
inters.append(self.start * other.end)
inters.append(self.end * other.end)
start = min(inters)
end = max(inters)
return interval(start, end)
elif isinstance(other, (int, float)):
return interval(self.start*other, self.end*other, is_valid=self.is_valid)
else:
return NotImplemented
__rmul__ = __mul__
def __contains__(self, other):
if isinstance(other, (int, float)):
return self.start <= other and self.end >= other
else:
return self.start <= other.start and other.end <= self.end
def __rtruediv__(self, other):
if isinstance(other, (int, float)):
other = interval(other)
return other.__truediv__(self)
elif isinstance(other, interval):
return other.__truediv__(self)
else:
return NotImplemented
def __truediv__(self, other):
# Both None and False are handled
if not self.is_valid:
# Don't divide as the value is not valid
return interval(-float('inf'), float('inf'), is_valid=self.is_valid)
if isinstance(other, (int, float)):
if other == 0:
# Divide by zero encountered. valid nowhere
return interval(-float('inf'), float('inf'), is_valid=False)
else:
return interval(self.start / other, self.end / other)
elif isinstance(other, interval):
if other.is_valid is False or self.is_valid is False:
return interval(-float('inf'), float('inf'), is_valid=False)
elif other.is_valid is None or self.is_valid is None:
return interval(-float('inf'), float('inf'), is_valid=None)
else:
# denominator contains both signs, i.e. being divided by zero
# return the whole real line with is_valid = None
if 0 in other:
return interval(-float('inf'), float('inf'), is_valid=None)
# denominator negative
this = self
if other.end < 0:
this = -this
other = -other
# denominator positive
inters = []
inters.append(this.start / other.start)
inters.append(this.end / other.start)
inters.append(this.start / other.end)
inters.append(this.end / other.end)
start = max(inters)
end = min(inters)
return interval(start, end)
else:
return NotImplemented
def __pow__(self, other):
# Implements only power to an integer.
from .lib_interval import exp, log
if not self.is_valid:
return self
if isinstance(other, interval):
return exp(other * log(self))
elif isinstance(other, (float, int)):
if other < 0:
return 1 / self.__pow__(abs(other))
else:
if int_valued(other):
return _pow_int(self, other)
else:
return _pow_float(self, other)
else:
return NotImplemented
def __rpow__(self, other):
if isinstance(other, (float, int)):
if not self.is_valid:
#Don't do anything
return self
elif other < 0:
if self.width > 0:
return interval(-float('inf'), float('inf'), is_valid=False)
else:
power_rational = nsimplify(self.start)
num, denom = power_rational.as_numer_denom()
if denom % 2 == 0:
return interval(-float('inf'), float('inf'),
is_valid=False)
else:
start = -abs(other)**self.start
end = start
return interval(start, end)
else:
return interval(other**self.start, other**self.end)
elif isinstance(other, interval):
return other.__pow__(self)
else:
return NotImplemented
def __hash__(self):
return hash((self.is_valid, self.start, self.end))
def _pow_float(inter, power):
"""Evaluates an interval raised to a floating point."""
power_rational = nsimplify(power)
num, denom = power_rational.as_numer_denom()
if num % 2 == 0:
start = abs(inter.start)**power
end = abs(inter.end)**power
if start < 0:
ret = interval(0, max(start, end))
else:
ret = interval(start, end)
return ret
elif denom % 2 == 0:
if inter.end < 0:
return interval(-float('inf'), float('inf'), is_valid=False)
elif inter.start < 0:
return interval(0, inter.end**power, is_valid=None)
else:
return interval(inter.start**power, inter.end**power)
else:
if inter.start < 0:
start = -abs(inter.start)**power
else:
start = inter.start**power
if inter.end < 0:
end = -abs(inter.end)**power
else:
end = inter.end**power
return interval(start, end, is_valid=inter.is_valid)
def _pow_int(inter, power):
"""Evaluates an interval raised to an integer power"""
power = int(power)
if power & 1:
return interval(inter.start**power, inter.end**power)
else:
if inter.start < 0 and inter.end > 0:
start = 0
end = max(inter.start**power, inter.end**power)
return interval(start, end)
else:
return interval(inter.start**power, inter.end**power)
PK ]ZZZ����Q Q 2 sympy/plotting/intervalmath/interval_membership.pyfrom sympy.core.logic import fuzzy_and, fuzzy_or, fuzzy_not, fuzzy_xor
class intervalMembership:
"""Represents a boolean expression returned by the comparison of
the interval object.
Parameters
==========
(a, b) : (bool, bool)
The first value determines the comparison as follows:
- True: If the comparison is True throughout the intervals.
- False: If the comparison is False throughout the intervals.
- None: If the comparison is True for some part of the intervals.
The second value is determined as follows:
- True: If both the intervals in comparison are valid.
- False: If at least one of the intervals is False, else
- None
"""
def __init__(self, a, b):
self._wrapped = (a, b)
def __getitem__(self, i):
try:
return self._wrapped[i]
except IndexError:
raise IndexError(
"{} must be a valid indexing for the 2-tuple."
.format(i))
def __len__(self):
return 2
def __iter__(self):
return iter(self._wrapped)
def __str__(self):
return "intervalMembership({}, {})".format(*self)
__repr__ = __str__
def __and__(self, other):
if not isinstance(other, intervalMembership):
raise ValueError(
"The comparison is not supported for {}.".format(other))
a1, b1 = self
a2, b2 = other
return intervalMembership(fuzzy_and([a1, a2]), fuzzy_and([b1, b2]))
def __or__(self, other):
if not isinstance(other, intervalMembership):
raise ValueError(
"The comparison is not supported for {}.".format(other))
a1, b1 = self
a2, b2 = other
return intervalMembership(fuzzy_or([a1, a2]), fuzzy_and([b1, b2]))
def __invert__(self):
a, b = self
return intervalMembership(fuzzy_not(a), b)
def __xor__(self, other):
if not isinstance(other, intervalMembership):
raise ValueError(
"The comparison is not supported for {}.".format(other))
a1, b1 = self
a2, b2 = other
return intervalMembership(fuzzy_xor([a1, a2]), fuzzy_and([b1, b2]))
def __eq__(self, other):
return self._wrapped == other
def __ne__(self, other):
return self._wrapped != other
PK ]ZZZem��9 �9 + sympy/plotting/intervalmath/lib_interval.py""" The module contains implemented functions for interval arithmetic."""
from functools import reduce
from sympy.plotting.intervalmath import interval
from sympy.external import import_module
def Abs(x):
if isinstance(x, (int, float)):
return interval(abs(x))
elif isinstance(x, interval):
if x.start < 0 and x.end > 0:
return interval(0, max(abs(x.start), abs(x.end)), is_valid=x.is_valid)
else:
return interval(abs(x.start), abs(x.end))
else:
raise NotImplementedError
#Monotonic
def exp(x):
"""evaluates the exponential of an interval"""
np = import_module('numpy')
if isinstance(x, (int, float)):
return interval(np.exp(x), np.exp(x))
elif isinstance(x, interval):
return interval(np.exp(x.start), np.exp(x.end), is_valid=x.is_valid)
else:
raise NotImplementedError
#Monotonic
def log(x):
"""evaluates the natural logarithm of an interval"""
np = import_module('numpy')
if isinstance(x, (int, float)):
if x <= 0:
return interval(-np.inf, np.inf, is_valid=False)
else:
return interval(np.log(x))
elif isinstance(x, interval):
if not x.is_valid:
return interval(-np.inf, np.inf, is_valid=x.is_valid)
elif x.end <= 0:
return interval(-np.inf, np.inf, is_valid=False)
elif x.start <= 0:
return interval(-np.inf, np.inf, is_valid=None)
return interval(np.log(x.start), np.log(x.end))
else:
raise NotImplementedError
#Monotonic
def log10(x):
"""evaluates the logarithm to the base 10 of an interval"""
np = import_module('numpy')
if isinstance(x, (int, float)):
if x <= 0:
return interval(-np.inf, np.inf, is_valid=False)
else:
return interval(np.log10(x))
elif isinstance(x, interval):
if not x.is_valid:
return interval(-np.inf, np.inf, is_valid=x.is_valid)
elif x.end <= 0:
return interval(-np.inf, np.inf, is_valid=False)
elif x.start <= 0:
return interval(-np.inf, np.inf, is_valid=None)
return interval(np.log10(x.start), np.log10(x.end))
else:
raise NotImplementedError
#Monotonic
def atan(x):
"""evaluates the tan inverse of an interval"""
np = import_module('numpy')
if isinstance(x, (int, float)):
return interval(np.arctan(x))
elif isinstance(x, interval):
start = np.arctan(x.start)
end = np.arctan(x.end)
return interval(start, end, is_valid=x.is_valid)
else:
raise NotImplementedError
#periodic
def sin(x):
"""evaluates the sine of an interval"""
np = import_module('numpy')
if isinstance(x, (int, float)):
return interval(np.sin(x))
elif isinstance(x, interval):
if not x.is_valid:
return interval(-1, 1, is_valid=x.is_valid)
na, __ = divmod(x.start, np.pi / 2.0)
nb, __ = divmod(x.end, np.pi / 2.0)
start = min(np.sin(x.start), np.sin(x.end))
end = max(np.sin(x.start), np.sin(x.end))
if nb - na > 4:
return interval(-1, 1, is_valid=x.is_valid)
elif na == nb:
return interval(start, end, is_valid=x.is_valid)
else:
if (na - 1) // 4 != (nb - 1) // 4:
#sin has max
end = 1
if (na - 3) // 4 != (nb - 3) // 4:
#sin has min
start = -1
return interval(start, end)
else:
raise NotImplementedError
#periodic
def cos(x):
"""Evaluates the cos of an interval"""
np = import_module('numpy')
if isinstance(x, (int, float)):
return interval(np.sin(x))
elif isinstance(x, interval):
if not (np.isfinite(x.start) and np.isfinite(x.end)):
return interval(-1, 1, is_valid=x.is_valid)
na, __ = divmod(x.start, np.pi / 2.0)
nb, __ = divmod(x.end, np.pi / 2.0)
start = min(np.cos(x.start), np.cos(x.end))
end = max(np.cos(x.start), np.cos(x.end))
if nb - na > 4:
#differ more than 2*pi
return interval(-1, 1, is_valid=x.is_valid)
elif na == nb:
#in the same quadarant
return interval(start, end, is_valid=x.is_valid)
else:
if (na) // 4 != (nb) // 4:
#cos has max
end = 1
if (na - 2) // 4 != (nb - 2) // 4:
#cos has min
start = -1
return interval(start, end, is_valid=x.is_valid)
else:
raise NotImplementedError
def tan(x):
"""Evaluates the tan of an interval"""
return sin(x) / cos(x)
#Monotonic
def sqrt(x):
"""Evaluates the square root of an interval"""
np = import_module('numpy')
if isinstance(x, (int, float)):
if x > 0:
return interval(np.sqrt(x))
else:
return interval(-np.inf, np.inf, is_valid=False)
elif isinstance(x, interval):
#Outside the domain
if x.end < 0:
return interval(-np.inf, np.inf, is_valid=False)
#Partially outside the domain
elif x.start < 0:
return interval(-np.inf, np.inf, is_valid=None)
else:
return interval(np.sqrt(x.start), np.sqrt(x.end),
is_valid=x.is_valid)
else:
raise NotImplementedError
def imin(*args):
"""Evaluates the minimum of a list of intervals"""
np = import_module('numpy')
if not all(isinstance(arg, (int, float, interval)) for arg in args):
return NotImplementedError
else:
new_args = [a for a in args if isinstance(a, (int, float))
or a.is_valid]
if len(new_args) == 0:
if all(a.is_valid is False for a in args):
return interval(-np.inf, np.inf, is_valid=False)
else:
return interval(-np.inf, np.inf, is_valid=None)
start_array = [a if isinstance(a, (int, float)) else a.start
for a in new_args]
end_array = [a if isinstance(a, (int, float)) else a.end
for a in new_args]
return interval(min(start_array), min(end_array))
def imax(*args):
"""Evaluates the maximum of a list of intervals"""
np = import_module('numpy')
if not all(isinstance(arg, (int, float, interval)) for arg in args):
return NotImplementedError
else:
new_args = [a for a in args if isinstance(a, (int, float))
or a.is_valid]
if len(new_args) == 0:
if all(a.is_valid is False for a in args):
return interval(-np.inf, np.inf, is_valid=False)
else:
return interval(-np.inf, np.inf, is_valid=None)
start_array = [a if isinstance(a, (int, float)) else a.start
for a in new_args]
end_array = [a if isinstance(a, (int, float)) else a.end
for a in new_args]
return interval(max(start_array), max(end_array))
#Monotonic
def sinh(x):
"""Evaluates the hyperbolic sine of an interval"""
np = import_module('numpy')
if isinstance(x, (int, float)):
return interval(np.sinh(x), np.sinh(x))
elif isinstance(x, interval):
return interval(np.sinh(x.start), np.sinh(x.end), is_valid=x.is_valid)
else:
raise NotImplementedError
def cosh(x):
"""Evaluates the hyperbolic cos of an interval"""
np = import_module('numpy')
if isinstance(x, (int, float)):
return interval(np.cosh(x), np.cosh(x))
elif isinstance(x, interval):
#both signs
if x.start < 0 and x.end > 0:
end = max(np.cosh(x.start), np.cosh(x.end))
return interval(1, end, is_valid=x.is_valid)
else:
#Monotonic
start = np.cosh(x.start)
end = np.cosh(x.end)
return interval(start, end, is_valid=x.is_valid)
else:
raise NotImplementedError
#Monotonic
def tanh(x):
"""Evaluates the hyperbolic tan of an interval"""
np = import_module('numpy')
if isinstance(x, (int, float)):
return interval(np.tanh(x), np.tanh(x))
elif isinstance(x, interval):
return interval(np.tanh(x.start), np.tanh(x.end), is_valid=x.is_valid)
else:
raise NotImplementedError
def asin(x):
"""Evaluates the inverse sine of an interval"""
np = import_module('numpy')
if isinstance(x, (int, float)):
#Outside the domain
if abs(x) > 1:
return interval(-np.inf, np.inf, is_valid=False)
else:
return interval(np.arcsin(x), np.arcsin(x))
elif isinstance(x, interval):
#Outside the domain
if x.is_valid is False or x.start > 1 or x.end < -1:
return interval(-np.inf, np.inf, is_valid=False)
#Partially outside the domain
elif x.start < -1 or x.end > 1:
return interval(-np.inf, np.inf, is_valid=None)
else:
start = np.arcsin(x.start)
end = np.arcsin(x.end)
return interval(start, end, is_valid=x.is_valid)
def acos(x):
"""Evaluates the inverse cos of an interval"""
np = import_module('numpy')
if isinstance(x, (int, float)):
if abs(x) > 1:
#Outside the domain
return interval(-np.inf, np.inf, is_valid=False)
else:
return interval(np.arccos(x), np.arccos(x))
elif isinstance(x, interval):
#Outside the domain
if x.is_valid is False or x.start > 1 or x.end < -1:
return interval(-np.inf, np.inf, is_valid=False)
#Partially outside the domain
elif x.start < -1 or x.end > 1:
return interval(-np.inf, np.inf, is_valid=None)
else:
start = np.arccos(x.start)
end = np.arccos(x.end)
return interval(start, end, is_valid=x.is_valid)
def ceil(x):
"""Evaluates the ceiling of an interval"""
np = import_module('numpy')
if isinstance(x, (int, float)):
return interval(np.ceil(x))
elif isinstance(x, interval):
if x.is_valid is False:
return interval(-np.inf, np.inf, is_valid=False)
else:
start = np.ceil(x.start)
end = np.ceil(x.end)
#Continuous over the interval
if start == end:
return interval(start, end, is_valid=x.is_valid)
else:
#Not continuous over the interval
return interval(start, end, is_valid=None)
else:
return NotImplementedError
def floor(x):
"""Evaluates the floor of an interval"""
np = import_module('numpy')
if isinstance(x, (int, float)):
return interval(np.floor(x))
elif isinstance(x, interval):
if x.is_valid is False:
return interval(-np.inf, np.inf, is_valid=False)
else:
start = np.floor(x.start)
end = np.floor(x.end)
#continuous over the argument
if start == end:
return interval(start, end, is_valid=x.is_valid)
else:
#not continuous over the interval
return interval(start, end, is_valid=None)
else:
return NotImplementedError
def acosh(x):
"""Evaluates the inverse hyperbolic cosine of an interval"""
np = import_module('numpy')
if isinstance(x, (int, float)):
#Outside the domain
if x < 1:
return interval(-np.inf, np.inf, is_valid=False)
else:
return interval(np.arccosh(x))
elif isinstance(x, interval):
#Outside the domain
if x.end < 1:
return interval(-np.inf, np.inf, is_valid=False)
#Partly outside the domain
elif x.start < 1:
return interval(-np.inf, np.inf, is_valid=None)
else:
start = np.arccosh(x.start)
end = np.arccosh(x.end)
return interval(start, end, is_valid=x.is_valid)
else:
return NotImplementedError
#Monotonic
def asinh(x):
"""Evaluates the inverse hyperbolic sine of an interval"""
np = import_module('numpy')
if isinstance(x, (int, float)):
return interval(np.arcsinh(x))
elif isinstance(x, interval):
start = np.arcsinh(x.start)
end = np.arcsinh(x.end)
return interval(start, end, is_valid=x.is_valid)
else:
return NotImplementedError
def atanh(x):
"""Evaluates the inverse hyperbolic tangent of an interval"""
np = import_module('numpy')
if isinstance(x, (int, float)):
#Outside the domain
if abs(x) >= 1:
return interval(-np.inf, np.inf, is_valid=False)
else:
return interval(np.arctanh(x))
elif isinstance(x, interval):
#outside the domain
if x.is_valid is False or x.start >= 1 or x.end <= -1:
return interval(-np.inf, np.inf, is_valid=False)
#partly outside the domain
elif x.start <= -1 or x.end >= 1:
return interval(-np.inf, np.inf, is_valid=None)
else:
start = np.arctanh(x.start)
end = np.arctanh(x.end)
return interval(start, end, is_valid=x.is_valid)
else:
return NotImplementedError
#Three valued logic for interval plotting.
def And(*args):
"""Defines the three valued ``And`` behaviour for a 2-tuple of
three valued logic values"""
def reduce_and(cmp_intervala, cmp_intervalb):
if cmp_intervala[0] is False or cmp_intervalb[0] is False:
first = False
elif cmp_intervala[0] is None or cmp_intervalb[0] is None:
first = None
else:
first = True
if cmp_intervala[1] is False or cmp_intervalb[1] is False:
second = False
elif cmp_intervala[1] is None or cmp_intervalb[1] is None:
second = None
else:
second = True
return (first, second)
return reduce(reduce_and, args)
def Or(*args):
"""Defines the three valued ``Or`` behaviour for a 2-tuple of
three valued logic values"""
def reduce_or(cmp_intervala, cmp_intervalb):
if cmp_intervala[0] is True or cmp_intervalb[0] is True:
first = True
elif cmp_intervala[0] is None or cmp_intervalb[0] is None:
first = None
else:
first = False
if cmp_intervala[1] is True or cmp_intervalb[1] is True:
second = True
elif cmp_intervala[1] is None or cmp_intervalb[1] is None:
second = None
else:
second = False
return (first, second)
return reduce(reduce_or, args)
PK ]ZZZ��&� � % sympy/plotting/pygletplot/__init__.py"""Plotting module that can plot 2D and 3D functions
"""
from sympy.utilities.decorator import doctest_depends_on
@doctest_depends_on(modules=('pyglet',))
def PygletPlot(*args, **kwargs):
"""
Plot Examples
=============
See examples/advanced/pyglet_plotting.py for many more examples.
>>> from sympy.plotting.pygletplot import PygletPlot as Plot
>>> from sympy.abc import x, y, z
>>> Plot(x*y**3-y*x**3)
[0]: -x**3*y + x*y**3, 'mode=cartesian'
>>> p = Plot()
>>> p[1] = x*y
>>> p[1].color = z, (0.4,0.4,0.9), (0.9,0.4,0.4)
>>> p = Plot()
>>> p[1] = x**2+y**2
>>> p[2] = -x**2-y**2
Variable Intervals
==================
The basic format is [var, min, max, steps], but the
syntax is flexible and arguments left out are taken
from the defaults for the current coordinate mode:
>>> Plot(x**2) # implies [x,-5,5,100]
[0]: x**2, 'mode=cartesian'
>>> Plot(x**2, [], []) # [x,-1,1,40], [y,-1,1,40]
[0]: x**2, 'mode=cartesian'
>>> Plot(x**2-y**2, [100], [100]) # [x,-1,1,100], [y,-1,1,100]
[0]: x**2 - y**2, 'mode=cartesian'
>>> Plot(x**2, [x,-13,13,100])
[0]: x**2, 'mode=cartesian'
>>> Plot(x**2, [-13,13]) # [x,-13,13,100]
[0]: x**2, 'mode=cartesian'
>>> Plot(x**2, [x,-13,13]) # [x,-13,13,100]
[0]: x**2, 'mode=cartesian'
>>> Plot(1*x, [], [x], mode='cylindrical')
... # [unbound_theta,0,2*Pi,40], [x,-1,1,20]
[0]: x, 'mode=cartesian'
Coordinate Modes
================
Plot supports several curvilinear coordinate modes, and
they independent for each plotted function. You can specify
a coordinate mode explicitly with the 'mode' named argument,
but it can be automatically determined for Cartesian or
parametric plots, and therefore must only be specified for
polar, cylindrical, and spherical modes.
Specifically, Plot(function arguments) and Plot[n] =
(function arguments) will interpret your arguments as a
Cartesian plot if you provide one function and a parametric
plot if you provide two or three functions. Similarly, the
arguments will be interpreted as a curve if one variable is
used, and a surface if two are used.
Supported mode names by number of variables:
1: parametric, cartesian, polar
2: parametric, cartesian, cylindrical = polar, spherical
>>> Plot(1, mode='spherical')
Calculator-like Interface
=========================
>>> p = Plot(visible=False)
>>> f = x**2
>>> p[1] = f
>>> p[2] = f.diff(x)
>>> p[3] = f.diff(x).diff(x)
>>> p
[1]: x**2, 'mode=cartesian'
[2]: 2*x, 'mode=cartesian'
[3]: 2, 'mode=cartesian'
>>> p.show()
>>> p.clear()
>>> p
<blank plot>
>>> p[1] = x**2+y**2
>>> p[1].style = 'solid'
>>> p[2] = -x**2-y**2
>>> p[2].style = 'wireframe'
>>> p[1].color = z, (0.4,0.4,0.9), (0.9,0.4,0.4)
>>> p[1].style = 'both'
>>> p[2].style = 'both'
>>> p.close()
Plot Window Keyboard Controls
=============================
Screen Rotation:
X,Y axis Arrow Keys, A,S,D,W, Numpad 4,6,8,2
Z axis Q,E, Numpad 7,9
Model Rotation:
Z axis Z,C, Numpad 1,3
Zoom: R,F, PgUp,PgDn, Numpad +,-
Reset Camera: X, Numpad 5
Camera Presets:
XY F1
XZ F2
YZ F3
Perspective F4
Sensitivity Modifier: SHIFT
Axes Toggle:
Visible F5
Colors F6
Close Window: ESCAPE
=============================
"""
from sympy.plotting.pygletplot.plot import PygletPlot
return PygletPlot(*args, **kwargs)
PK ]ZZZc��0 �0 ) sympy/plotting/pygletplot/color_scheme.pyfrom sympy.core.basic import Basic
from sympy.core.symbol import (Symbol, symbols)
from sympy.utilities.lambdify import lambdify
from .util import interpolate, rinterpolate, create_bounds, update_bounds
from sympy.utilities.iterables import sift
class ColorGradient:
colors = [0.4, 0.4, 0.4], [0.9, 0.9, 0.9]
intervals = 0.0, 1.0
def __init__(self, *args):
if len(args) == 2:
self.colors = list(args)
self.intervals = [0.0, 1.0]
elif len(args) > 0:
if len(args) % 2 != 0:
raise ValueError("len(args) should be even")
self.colors = [args[i] for i in range(1, len(args), 2)]
self.intervals = [args[i] for i in range(0, len(args), 2)]
assert len(self.colors) == len(self.intervals)
def copy(self):
c = ColorGradient()
c.colors = [e[::] for e in self.colors]
c.intervals = self.intervals[::]
return c
def _find_interval(self, v):
m = len(self.intervals)
i = 0
while i < m - 1 and self.intervals[i] <= v:
i += 1
return i
def _interpolate_axis(self, axis, v):
i = self._find_interval(v)
v = rinterpolate(self.intervals[i - 1], self.intervals[i], v)
return interpolate(self.colors[i - 1][axis], self.colors[i][axis], v)
def __call__(self, r, g, b):
c = self._interpolate_axis
return c(0, r), c(1, g), c(2, b)
default_color_schemes = {} # defined at the bottom of this file
class ColorScheme:
def __init__(self, *args, **kwargs):
self.args = args
self.f, self.gradient = None, ColorGradient()
if len(args) == 1 and not isinstance(args[0], Basic) and callable(args[0]):
self.f = args[0]
elif len(args) == 1 and isinstance(args[0], str):
if args[0] in default_color_schemes:
cs = default_color_schemes[args[0]]
self.f, self.gradient = cs.f, cs.gradient.copy()
else:
self.f = lambdify('x,y,z,u,v', args[0])
else:
self.f, self.gradient = self._interpret_args(args)
self._test_color_function()
if not isinstance(self.gradient, ColorGradient):
raise ValueError("Color gradient not properly initialized. "
"(Not a ColorGradient instance.)")
def _interpret_args(self, args):
f, gradient = None, self.gradient
atoms, lists = self._sort_args(args)
s = self._pop_symbol_list(lists)
s = self._fill_in_vars(s)
# prepare the error message for lambdification failure
f_str = ', '.join(str(fa) for fa in atoms)
s_str = (str(sa) for sa in s)
s_str = ', '.join(sa for sa in s_str if sa.find('unbound') < 0)
f_error = ValueError("Could not interpret arguments "
"%s as functions of %s." % (f_str, s_str))
# try to lambdify args
if len(atoms) == 1:
fv = atoms[0]
try:
f = lambdify(s, [fv, fv, fv])
except TypeError:
raise f_error
elif len(atoms) == 3:
fr, fg, fb = atoms
try:
f = lambdify(s, [fr, fg, fb])
except TypeError:
raise f_error
else:
raise ValueError("A ColorScheme must provide 1 or 3 "
"functions in x, y, z, u, and/or v.")
# try to intrepret any given color information
if len(lists) == 0:
gargs = []
elif len(lists) == 1:
gargs = lists[0]
elif len(lists) == 2:
try:
(r1, g1, b1), (r2, g2, b2) = lists
except TypeError:
raise ValueError("If two color arguments are given, "
"they must be given in the format "
"(r1, g1, b1), (r2, g2, b2).")
gargs = lists
elif len(lists) == 3:
try:
(r1, r2), (g1, g2), (b1, b2) = lists
except Exception:
raise ValueError("If three color arguments are given, "
"they must be given in the format "
"(r1, r2), (g1, g2), (b1, b2). To create "
"a multi-step gradient, use the syntax "
"[0, colorStart, step1, color1, ..., 1, "
"colorEnd].")
gargs = [[r1, g1, b1], [r2, g2, b2]]
else:
raise ValueError("Don't know what to do with collection "
"arguments %s." % (', '.join(str(l) for l in lists)))
if gargs:
try:
gradient = ColorGradient(*gargs)
except Exception as ex:
raise ValueError(("Could not initialize a gradient "
"with arguments %s. Inner "
"exception: %s") % (gargs, str(ex)))
return f, gradient
def _pop_symbol_list(self, lists):
symbol_lists = []
for l in lists:
mark = True
for s in l:
if s is not None and not isinstance(s, Symbol):
mark = False
break
if mark:
lists.remove(l)
symbol_lists.append(l)
if len(symbol_lists) == 1:
return symbol_lists[0]
elif len(symbol_lists) == 0:
return []
else:
raise ValueError("Only one list of Symbols "
"can be given for a color scheme.")
def _fill_in_vars(self, args):
defaults = symbols('x,y,z,u,v')
v_error = ValueError("Could not find what to plot.")
if len(args) == 0:
return defaults
if not isinstance(args, (tuple, list)):
raise v_error
if len(args) == 0:
return defaults
for s in args:
if s is not None and not isinstance(s, Symbol):
raise v_error
# when vars are given explicitly, any vars
# not given are marked 'unbound' as to not
# be accidentally used in an expression
vars = [Symbol('unbound%i' % (i)) for i in range(1, 6)]
# interpret as t
if len(args) == 1:
vars[3] = args[0]
# interpret as u,v
elif len(args) == 2:
if args[0] is not None:
vars[3] = args[0]
if args[1] is not None:
vars[4] = args[1]
# interpret as x,y,z
elif len(args) >= 3:
# allow some of x,y,z to be
# left unbound if not given
if args[0] is not None:
vars[0] = args[0]
if args[1] is not None:
vars[1] = args[1]
if args[2] is not None:
vars[2] = args[2]
# interpret the rest as t
if len(args) >= 4:
vars[3] = args[3]
# ...or u,v
if len(args) >= 5:
vars[4] = args[4]
return vars
def _sort_args(self, args):
lists, atoms = sift(args,
lambda a: isinstance(a, (tuple, list)), binary=True)
return atoms, lists
def _test_color_function(self):
if not callable(self.f):
raise ValueError("Color function is not callable.")
try:
result = self.f(0, 0, 0, 0, 0)
if len(result) != 3:
raise ValueError("length should be equal to 3")
except TypeError:
raise ValueError("Color function needs to accept x,y,z,u,v, "
"as arguments even if it doesn't use all of them.")
except AssertionError:
raise ValueError("Color function needs to return 3-tuple r,g,b.")
except Exception:
pass # color function probably not valid at 0,0,0,0,0
def __call__(self, x, y, z, u, v):
try:
return self.f(x, y, z, u, v)
except Exception:
return None
def apply_to_curve(self, verts, u_set, set_len=None, inc_pos=None):
"""
Apply this color scheme to a
set of vertices over a single
independent variable u.
"""
bounds = create_bounds()
cverts = []
if callable(set_len):
set_len(len(u_set)*2)
# calculate f() = r,g,b for each vert
# and find the min and max for r,g,b
for _u in range(len(u_set)):
if verts[_u] is None:
cverts.append(None)
else:
x, y, z = verts[_u]
u, v = u_set[_u], None
c = self(x, y, z, u, v)
if c is not None:
c = list(c)
update_bounds(bounds, c)
cverts.append(c)
if callable(inc_pos):
inc_pos()
# scale and apply gradient
for _u in range(len(u_set)):
if cverts[_u] is not None:
for _c in range(3):
# scale from [f_min, f_max] to [0,1]
cverts[_u][_c] = rinterpolate(bounds[_c][0], bounds[_c][1],
cverts[_u][_c])
# apply gradient
cverts[_u] = self.gradient(*cverts[_u])
if callable(inc_pos):
inc_pos()
return cverts
def apply_to_surface(self, verts, u_set, v_set, set_len=None, inc_pos=None):
"""
Apply this color scheme to a
set of vertices over two
independent variables u and v.
"""
bounds = create_bounds()
cverts = []
if callable(set_len):
set_len(len(u_set)*len(v_set)*2)
# calculate f() = r,g,b for each vert
# and find the min and max for r,g,b
for _u in range(len(u_set)):
column = []
for _v in range(len(v_set)):
if verts[_u][_v] is None:
column.append(None)
else:
x, y, z = verts[_u][_v]
u, v = u_set[_u], v_set[_v]
c = self(x, y, z, u, v)
if c is not None:
c = list(c)
update_bounds(bounds, c)
column.append(c)
if callable(inc_pos):
inc_pos()
cverts.append(column)
# scale and apply gradient
for _u in range(len(u_set)):
for _v in range(len(v_set)):
if cverts[_u][_v] is not None:
# scale from [f_min, f_max] to [0,1]
for _c in range(3):
cverts[_u][_v][_c] = rinterpolate(bounds[_c][0],
bounds[_c][1], cverts[_u][_v][_c])
# apply gradient
cverts[_u][_v] = self.gradient(*cverts[_u][_v])
if callable(inc_pos):
inc_pos()
return cverts
def str_base(self):
return ", ".join(str(a) for a in self.args)
def __repr__(self):
return "%s" % (self.str_base())
x, y, z, t, u, v = symbols('x,y,z,t,u,v')
default_color_schemes['rainbow'] = ColorScheme(z, y, x)
default_color_schemes['zfade'] = ColorScheme(z, (0.4, 0.4, 0.97),
(0.97, 0.4, 0.4), (None, None, z))
default_color_schemes['zfade3'] = ColorScheme(z, (None, None, z),
[0.00, (0.2, 0.2, 1.0),
0.35, (0.2, 0.8, 0.4),
0.50, (0.3, 0.9, 0.3),
0.65, (0.4, 0.8, 0.2),
1.00, (1.0, 0.2, 0.2)])
default_color_schemes['zfade4'] = ColorScheme(z, (None, None, z),
[0.0, (0.3, 0.3, 1.0),
0.30, (0.3, 1.0, 0.3),
0.55, (0.95, 1.0, 0.2),
0.65, (1.0, 0.95, 0.2),
0.85, (1.0, 0.7, 0.2),
1.0, (1.0, 0.3, 0.2)])
PK ]ZZZ~�.� + sympy/plotting/pygletplot/managed_window.pyfrom pyglet.window import Window
from pyglet.clock import Clock
from threading import Thread, Lock
gl_lock = Lock()
class ManagedWindow(Window):
"""
A pyglet window with an event loop which executes automatically
in a separate thread. Behavior is added by creating a subclass
which overrides setup, update, and/or draw.
"""
fps_limit = 30
default_win_args = {"width": 600,
"height": 500,
"vsync": False,
"resizable": True}
def __init__(self, **win_args):
"""
It is best not to override this function in the child
class, unless you need to take additional arguments.
Do any OpenGL initialization calls in setup().
"""
# check if this is run from the doctester
if win_args.get('runfromdoctester', False):
return
self.win_args = dict(self.default_win_args, **win_args)
self.Thread = Thread(target=self.__event_loop__)
self.Thread.start()
def __event_loop__(self, **win_args):
"""
The event loop thread function. Do not override or call
directly (it is called by __init__).
"""
gl_lock.acquire()
try:
try:
super().__init__(**self.win_args)
self.switch_to()
self.setup()
except Exception as e:
print("Window initialization failed: %s" % (str(e)))
self.has_exit = True
finally:
gl_lock.release()
clock = Clock()
clock.fps_limit = self.fps_limit
while not self.has_exit:
dt = clock.tick()
gl_lock.acquire()
try:
try:
self.switch_to()
self.dispatch_events()
self.clear()
self.update(dt)
self.draw()
self.flip()
except Exception as e:
print("Uncaught exception in event loop: %s" % str(e))
self.has_exit = True
finally:
gl_lock.release()
super().close()
def close(self):
"""
Closes the window.
"""
self.has_exit = True
def setup(self):
"""
Called once before the event loop begins.
Override this method in a child class. This
is the best place to put things like OpenGL
initialization calls.
"""
pass
def update(self, dt):
"""
Called before draw during each iteration of
the event loop. dt is the elapsed time in
seconds since the last update. OpenGL rendering
calls are best put in draw() rather than here.
"""
pass
def draw(self):
"""
Called after update during each iteration of
the event loop. Put OpenGL rendering calls
here.
"""
pass
if __name__ == '__main__':
ManagedWindow()
PK ]ZZZdD��(4 (4 ! sympy/plotting/pygletplot/plot.pyfrom threading import RLock
# it is sufficient to import "pyglet" here once
try:
import pyglet.gl as pgl
except ImportError:
raise ImportError("pyglet is required for plotting.\n "
"visit https://pyglet.org/")
from sympy.core.numbers import Integer
from sympy.external.gmpy import SYMPY_INTS
from sympy.geometry.entity import GeometryEntity
from sympy.plotting.pygletplot.plot_axes import PlotAxes
from sympy.plotting.pygletplot.plot_mode import PlotMode
from sympy.plotting.pygletplot.plot_object import PlotObject
from sympy.plotting.pygletplot.plot_window import PlotWindow
from sympy.plotting.pygletplot.util import parse_option_string
from sympy.utilities.decorator import doctest_depends_on
from sympy.utilities.iterables import is_sequence
from time import sleep
from os import getcwd, listdir
import ctypes
@doctest_depends_on(modules=('pyglet',))
class PygletPlot:
"""
Plot Examples
=============
See examples/advanced/pyglet_plotting.py for many more examples.
>>> from sympy.plotting.pygletplot import PygletPlot as Plot
>>> from sympy.abc import x, y, z
>>> Plot(x*y**3-y*x**3)
[0]: -x**3*y + x*y**3, 'mode=cartesian'
>>> p = Plot()
>>> p[1] = x*y
>>> p[1].color = z, (0.4,0.4,0.9), (0.9,0.4,0.4)
>>> p = Plot()
>>> p[1] = x**2+y**2
>>> p[2] = -x**2-y**2
Variable Intervals
==================
The basic format is [var, min, max, steps], but the
syntax is flexible and arguments left out are taken
from the defaults for the current coordinate mode:
>>> Plot(x**2) # implies [x,-5,5,100]
[0]: x**2, 'mode=cartesian'
>>> Plot(x**2, [], []) # [x,-1,1,40], [y,-1,1,40]
[0]: x**2, 'mode=cartesian'
>>> Plot(x**2-y**2, [100], [100]) # [x,-1,1,100], [y,-1,1,100]
[0]: x**2 - y**2, 'mode=cartesian'
>>> Plot(x**2, [x,-13,13,100])
[0]: x**2, 'mode=cartesian'
>>> Plot(x**2, [-13,13]) # [x,-13,13,100]
[0]: x**2, 'mode=cartesian'
>>> Plot(x**2, [x,-13,13]) # [x,-13,13,10]
[0]: x**2, 'mode=cartesian'
>>> Plot(1*x, [], [x], mode='cylindrical')
... # [unbound_theta,0,2*Pi,40], [x,-1,1,20]
[0]: x, 'mode=cartesian'
Coordinate Modes
================
Plot supports several curvilinear coordinate modes, and
they independent for each plotted function. You can specify
a coordinate mode explicitly with the 'mode' named argument,
but it can be automatically determined for Cartesian or
parametric plots, and therefore must only be specified for
polar, cylindrical, and spherical modes.
Specifically, Plot(function arguments) and Plot[n] =
(function arguments) will interpret your arguments as a
Cartesian plot if you provide one function and a parametric
plot if you provide two or three functions. Similarly, the
arguments will be interpreted as a curve if one variable is
used, and a surface if two are used.
Supported mode names by number of variables:
1: parametric, cartesian, polar
2: parametric, cartesian, cylindrical = polar, spherical
>>> Plot(1, mode='spherical')
Calculator-like Interface
=========================
>>> p = Plot(visible=False)
>>> f = x**2
>>> p[1] = f
>>> p[2] = f.diff(x)
>>> p[3] = f.diff(x).diff(x)
>>> p
[1]: x**2, 'mode=cartesian'
[2]: 2*x, 'mode=cartesian'
[3]: 2, 'mode=cartesian'
>>> p.show()
>>> p.clear()
>>> p
<blank plot>
>>> p[1] = x**2+y**2
>>> p[1].style = 'solid'
>>> p[2] = -x**2-y**2
>>> p[2].style = 'wireframe'
>>> p[1].color = z, (0.4,0.4,0.9), (0.9,0.4,0.4)
>>> p[1].style = 'both'
>>> p[2].style = 'both'
>>> p.close()
Plot Window Keyboard Controls
=============================
Screen Rotation:
X,Y axis Arrow Keys, A,S,D,W, Numpad 4,6,8,2
Z axis Q,E, Numpad 7,9
Model Rotation:
Z axis Z,C, Numpad 1,3
Zoom: R,F, PgUp,PgDn, Numpad +,-
Reset Camera: X, Numpad 5
Camera Presets:
XY F1
XZ F2
YZ F3
Perspective F4
Sensitivity Modifier: SHIFT
Axes Toggle:
Visible F5
Colors F6
Close Window: ESCAPE
=============================
"""
@doctest_depends_on(modules=('pyglet',))
def __init__(self, *fargs, **win_args):
"""
Positional Arguments
====================
Any given positional arguments are used to
initialize a plot function at index 1. In
other words...
>>> from sympy.plotting.pygletplot import PygletPlot as Plot
>>> from sympy.abc import x
>>> p = Plot(x**2, visible=False)
...is equivalent to...
>>> p = Plot(visible=False)
>>> p[1] = x**2
Note that in earlier versions of the plotting
module, you were able to specify multiple
functions in the initializer. This functionality
has been dropped in favor of better automatic
plot plot_mode detection.
Named Arguments
===============
axes
An option string of the form
"key1=value1; key2 = value2" which
can use the following options:
style = ordinate
none OR frame OR box OR ordinate
stride = 0.25
val OR (val_x, val_y, val_z)
overlay = True (draw on top of plot)
True OR False
colored = False (False uses Black,
True uses colors
R,G,B = X,Y,Z)
True OR False
label_axes = False (display axis names
at endpoints)
True OR False
visible = True (show immediately
True OR False
The following named arguments are passed as
arguments to window initialization:
antialiasing = True
True OR False
ortho = False
True OR False
invert_mouse_zoom = False
True OR False
"""
# Register the plot modes
from . import plot_modes # noqa
self._win_args = win_args
self._window = None
self._render_lock = RLock()
self._functions = {}
self._pobjects = []
self._screenshot = ScreenShot(self)
axe_options = parse_option_string(win_args.pop('axes', ''))
self.axes = PlotAxes(**axe_options)
self._pobjects.append(self.axes)
self[0] = fargs
if win_args.get('visible', True):
self.show()
## Window Interfaces
def show(self):
"""
Creates and displays a plot window, or activates it
(gives it focus) if it has already been created.
"""
if self._window and not self._window.has_exit:
self._window.activate()
else:
self._win_args['visible'] = True
self.axes.reset_resources()
#if hasattr(self, '_doctest_depends_on'):
# self._win_args['runfromdoctester'] = True
self._window = PlotWindow(self, **self._win_args)
def close(self):
"""
Closes the plot window.
"""
if self._window:
self._window.close()
def saveimage(self, outfile=None, format='', size=(600, 500)):
"""
Saves a screen capture of the plot window to an
image file.
If outfile is given, it can either be a path
or a file object. Otherwise a png image will
be saved to the current working directory.
If the format is omitted, it is determined from
the filename extension.
"""
self._screenshot.save(outfile, format, size)
## Function List Interfaces
def clear(self):
"""
Clears the function list of this plot.
"""
self._render_lock.acquire()
self._functions = {}
self.adjust_all_bounds()
self._render_lock.release()
def __getitem__(self, i):
"""
Returns the function at position i in the
function list.
"""
return self._functions[i]
def __setitem__(self, i, args):
"""
Parses and adds a PlotMode to the function
list.
"""
if not (isinstance(i, (SYMPY_INTS, Integer)) and i >= 0):
raise ValueError("Function index must "
"be an integer >= 0.")
if isinstance(args, PlotObject):
f = args
else:
if (not is_sequence(args)) or isinstance(args, GeometryEntity):
args = [args]
if len(args) == 0:
return # no arguments given
kwargs = {"bounds_callback": self.adjust_all_bounds}
f = PlotMode(*args, **kwargs)
if f:
self._render_lock.acquire()
self._functions[i] = f
self._render_lock.release()
else:
raise ValueError("Failed to parse '%s'."
% ', '.join(str(a) for a in args))
def __delitem__(self, i):
"""
Removes the function in the function list at
position i.
"""
self._render_lock.acquire()
del self._functions[i]
self.adjust_all_bounds()
self._render_lock.release()
def firstavailableindex(self):
"""
Returns the first unused index in the function list.
"""
i = 0
self._render_lock.acquire()
while i in self._functions:
i += 1
self._render_lock.release()
return i
def append(self, *args):
"""
Parses and adds a PlotMode to the function
list at the first available index.
"""
self.__setitem__(self.firstavailableindex(), args)
def __len__(self):
"""
Returns the number of functions in the function list.
"""
return len(self._functions)
def __iter__(self):
"""
Allows iteration of the function list.
"""
return self._functions.itervalues()
def __repr__(self):
return str(self)
def __str__(self):
"""
Returns a string containing a new-line separated
list of the functions in the function list.
"""
s = ""
if len(self._functions) == 0:
s += "<blank plot>"
else:
self._render_lock.acquire()
s += "\n".join(["%s[%i]: %s" % ("", i, str(self._functions[i]))
for i in self._functions])
self._render_lock.release()
return s
def adjust_all_bounds(self):
self._render_lock.acquire()
self.axes.reset_bounding_box()
for f in self._functions:
self.axes.adjust_bounds(self._functions[f].bounds)
self._render_lock.release()
def wait_for_calculations(self):
sleep(0)
self._render_lock.acquire()
for f in self._functions:
a = self._functions[f]._get_calculating_verts
b = self._functions[f]._get_calculating_cverts
while a() or b():
sleep(0)
self._render_lock.release()
class ScreenShot:
def __init__(self, plot):
self._plot = plot
self.screenshot_requested = False
self.outfile = None
self.format = ''
self.invisibleMode = False
self.flag = 0
def __bool__(self):
return self.screenshot_requested
def _execute_saving(self):
if self.flag < 3:
self.flag += 1
return
size_x, size_y = self._plot._window.get_size()
size = size_x*size_y*4*ctypes.sizeof(ctypes.c_ubyte)
image = ctypes.create_string_buffer(size)
pgl.glReadPixels(0, 0, size_x, size_y, pgl.GL_RGBA, pgl.GL_UNSIGNED_BYTE, image)
from PIL import Image
im = Image.frombuffer('RGBA', (size_x, size_y),
image.raw, 'raw', 'RGBA', 0, 1)
im.transpose(Image.FLIP_TOP_BOTTOM).save(self.outfile, self.format)
self.flag = 0
self.screenshot_requested = False
if self.invisibleMode:
self._plot._window.close()
def save(self, outfile=None, format='', size=(600, 500)):
self.outfile = outfile
self.format = format
self.size = size
self.screenshot_requested = True
if not self._plot._window or self._plot._window.has_exit:
self._plot._win_args['visible'] = False
self._plot._win_args['width'] = size[0]
self._plot._win_args['height'] = size[1]
self._plot.axes.reset_resources()
self._plot._window = PlotWindow(self._plot, **self._plot._win_args)
self.invisibleMode = True
if self.outfile is None:
self.outfile = self._create_unique_path()
print(self.outfile)
def _create_unique_path(self):
cwd = getcwd()
l = listdir(cwd)
path = ''
i = 0
while True:
if not 'plot_%s.png' % i in l:
path = cwd + '/plot_%s.png' % i
break
i += 1
return path
PK ]ZZZ`/��! �! & sympy/plotting/pygletplot/plot_axes.pyimport pyglet.gl as pgl
from pyglet import font
from sympy.core import S
from sympy.plotting.pygletplot.plot_object import PlotObject
from sympy.plotting.pygletplot.util import billboard_matrix, dot_product, \
get_direction_vectors, strided_range, vec_mag, vec_sub
from sympy.utilities.iterables import is_sequence
class PlotAxes(PlotObject):
def __init__(self, *args,
style='', none=None, frame=None, box=None, ordinate=None,
stride=0.25,
visible='', overlay='', colored='', label_axes='', label_ticks='',
tick_length=0.1,
font_face='Arial', font_size=28,
**kwargs):
# initialize style parameter
style = style.lower()
# allow alias kwargs to override style kwarg
if none is not None:
style = 'none'
if frame is not None:
style = 'frame'
if box is not None:
style = 'box'
if ordinate is not None:
style = 'ordinate'
if style in ['', 'ordinate']:
self._render_object = PlotAxesOrdinate(self)
elif style in ['frame', 'box']:
self._render_object = PlotAxesFrame(self)
elif style in ['none']:
self._render_object = None
else:
raise ValueError(("Unrecognized axes style %s.") % (style))
# initialize stride parameter
try:
stride = eval(stride)
except TypeError:
pass
if is_sequence(stride):
if len(stride) != 3:
raise ValueError("length should be equal to 3")
self._stride = stride
else:
self._stride = [stride, stride, stride]
self._tick_length = float(tick_length)
# setup bounding box and ticks
self._origin = [0, 0, 0]
self.reset_bounding_box()
def flexible_boolean(input, default):
if input in [True, False]:
return input
if input in ('f', 'F', 'false', 'False'):
return False
if input in ('t', 'T', 'true', 'True'):
return True
return default
# initialize remaining parameters
self.visible = flexible_boolean(kwargs, True)
self._overlay = flexible_boolean(overlay, True)
self._colored = flexible_boolean(colored, False)
self._label_axes = flexible_boolean(label_axes, False)
self._label_ticks = flexible_boolean(label_ticks, True)
# setup label font
self.font_face = font_face
self.font_size = font_size
# this is also used to reinit the
# font on window close/reopen
self.reset_resources()
def reset_resources(self):
self.label_font = None
def reset_bounding_box(self):
self._bounding_box = [[None, None], [None, None], [None, None]]
self._axis_ticks = [[], [], []]
def draw(self):
if self._render_object:
pgl.glPushAttrib(pgl.GL_ENABLE_BIT | pgl.GL_POLYGON_BIT | pgl.GL_DEPTH_BUFFER_BIT)
if self._overlay:
pgl.glDisable(pgl.GL_DEPTH_TEST)
self._render_object.draw()
pgl.glPopAttrib()
def adjust_bounds(self, child_bounds):
b = self._bounding_box
c = child_bounds
for i in range(3):
if abs(c[i][0]) is S.Infinity or abs(c[i][1]) is S.Infinity:
continue
b[i][0] = c[i][0] if b[i][0] is None else min([b[i][0], c[i][0]])
b[i][1] = c[i][1] if b[i][1] is None else max([b[i][1], c[i][1]])
self._bounding_box = b
self._recalculate_axis_ticks(i)
def _recalculate_axis_ticks(self, axis):
b = self._bounding_box
if b[axis][0] is None or b[axis][1] is None:
self._axis_ticks[axis] = []
else:
self._axis_ticks[axis] = strided_range(b[axis][0], b[axis][1],
self._stride[axis])
def toggle_visible(self):
self.visible = not self.visible
def toggle_colors(self):
self._colored = not self._colored
class PlotAxesBase(PlotObject):
def __init__(self, parent_axes):
self._p = parent_axes
def draw(self):
color = [([0.2, 0.1, 0.3], [0.2, 0.1, 0.3], [0.2, 0.1, 0.3]),
([0.9, 0.3, 0.5], [0.5, 1.0, 0.5], [0.3, 0.3, 0.9])][self._p._colored]
self.draw_background(color)
self.draw_axis(2, color[2])
self.draw_axis(1, color[1])
self.draw_axis(0, color[0])
def draw_background(self, color):
pass # optional
def draw_axis(self, axis, color):
raise NotImplementedError()
def draw_text(self, text, position, color, scale=1.0):
if len(color) == 3:
color = (color[0], color[1], color[2], 1.0)
if self._p.label_font is None:
self._p.label_font = font.load(self._p.font_face,
self._p.font_size,
bold=True, italic=False)
label = font.Text(self._p.label_font, text,
color=color,
valign=font.Text.BASELINE,
halign=font.Text.CENTER)
pgl.glPushMatrix()
pgl.glTranslatef(*position)
billboard_matrix()
scale_factor = 0.005 * scale
pgl.glScalef(scale_factor, scale_factor, scale_factor)
pgl.glColor4f(0, 0, 0, 0)
label.draw()
pgl.glPopMatrix()
def draw_line(self, v, color):
o = self._p._origin
pgl.glBegin(pgl.GL_LINES)
pgl.glColor3f(*color)
pgl.glVertex3f(v[0][0] + o[0], v[0][1] + o[1], v[0][2] + o[2])
pgl.glVertex3f(v[1][0] + o[0], v[1][1] + o[1], v[1][2] + o[2])
pgl.glEnd()
class PlotAxesOrdinate(PlotAxesBase):
def __init__(self, parent_axes):
super().__init__(parent_axes)
def draw_axis(self, axis, color):
ticks = self._p._axis_ticks[axis]
radius = self._p._tick_length / 2.0
if len(ticks) < 2:
return
# calculate the vector for this axis
axis_lines = [[0, 0, 0], [0, 0, 0]]
axis_lines[0][axis], axis_lines[1][axis] = ticks[0], ticks[-1]
axis_vector = vec_sub(axis_lines[1], axis_lines[0])
# calculate angle to the z direction vector
pos_z = get_direction_vectors()[2]
d = abs(dot_product(axis_vector, pos_z))
d = d / vec_mag(axis_vector)
# don't draw labels if we're looking down the axis
labels_visible = abs(d - 1.0) > 0.02
# draw the ticks and labels
for tick in ticks:
self.draw_tick_line(axis, color, radius, tick, labels_visible)
# draw the axis line and labels
self.draw_axis_line(axis, color, ticks[0], ticks[-1], labels_visible)
def draw_axis_line(self, axis, color, a_min, a_max, labels_visible):
axis_line = [[0, 0, 0], [0, 0, 0]]
axis_line[0][axis], axis_line[1][axis] = a_min, a_max
self.draw_line(axis_line, color)
if labels_visible:
self.draw_axis_line_labels(axis, color, axis_line)
def draw_axis_line_labels(self, axis, color, axis_line):
if not self._p._label_axes:
return
axis_labels = [axis_line[0][::], axis_line[1][::]]
axis_labels[0][axis] -= 0.3
axis_labels[1][axis] += 0.3
a_str = ['X', 'Y', 'Z'][axis]
self.draw_text("-" + a_str, axis_labels[0], color)
self.draw_text("+" + a_str, axis_labels[1], color)
def draw_tick_line(self, axis, color, radius, tick, labels_visible):
tick_axis = {0: 1, 1: 0, 2: 1}[axis]
tick_line = [[0, 0, 0], [0, 0, 0]]
tick_line[0][axis] = tick_line[1][axis] = tick
tick_line[0][tick_axis], tick_line[1][tick_axis] = -radius, radius
self.draw_line(tick_line, color)
if labels_visible:
self.draw_tick_line_label(axis, color, radius, tick)
def draw_tick_line_label(self, axis, color, radius, tick):
if not self._p._label_axes:
return
tick_label_vector = [0, 0, 0]
tick_label_vector[axis] = tick
tick_label_vector[{0: 1, 1: 0, 2: 1}[axis]] = [-1, 1, 1][
axis] * radius * 3.5
self.draw_text(str(tick), tick_label_vector, color, scale=0.5)
class PlotAxesFrame(PlotAxesBase):
def __init__(self, parent_axes):
super().__init__(parent_axes)
def draw_background(self, color):
pass
def draw_axis(self, axis, color):
raise NotImplementedError()
PK ]ZZZ �OX X ( sympy/plotting/pygletplot/plot_camera.pyimport pyglet.gl as pgl
from sympy.plotting.pygletplot.plot_rotation import get_spherical_rotatation
from sympy.plotting.pygletplot.util import get_model_matrix, model_to_screen, \
screen_to_model, vec_subs
class PlotCamera:
min_dist = 0.05
max_dist = 500.0
min_ortho_dist = 100.0
max_ortho_dist = 10000.0
_default_dist = 6.0
_default_ortho_dist = 600.0
rot_presets = {
'xy': (0, 0, 0),
'xz': (-90, 0, 0),
'yz': (0, 90, 0),
'perspective': (-45, 0, -45)
}
def __init__(self, window, ortho=False):
self.window = window
self.axes = self.window.plot.axes
self.ortho = ortho
self.reset()
def init_rot_matrix(self):
pgl.glPushMatrix()
pgl.glLoadIdentity()
self._rot = get_model_matrix()
pgl.glPopMatrix()
def set_rot_preset(self, preset_name):
self.init_rot_matrix()
if preset_name not in self.rot_presets:
raise ValueError(
"%s is not a valid rotation preset." % preset_name)
r = self.rot_presets[preset_name]
self.euler_rotate(r[0], 1, 0, 0)
self.euler_rotate(r[1], 0, 1, 0)
self.euler_rotate(r[2], 0, 0, 1)
def reset(self):
self._dist = 0.0
self._x, self._y = 0.0, 0.0
self._rot = None
if self.ortho:
self._dist = self._default_ortho_dist
else:
self._dist = self._default_dist
self.init_rot_matrix()
def mult_rot_matrix(self, rot):
pgl.glPushMatrix()
pgl.glLoadMatrixf(rot)
pgl.glMultMatrixf(self._rot)
self._rot = get_model_matrix()
pgl.glPopMatrix()
def setup_projection(self):
pgl.glMatrixMode(pgl.GL_PROJECTION)
pgl.glLoadIdentity()
if self.ortho:
# yep, this is pseudo ortho (don't tell anyone)
pgl.gluPerspective(
0.3, float(self.window.width)/float(self.window.height),
self.min_ortho_dist - 0.01, self.max_ortho_dist + 0.01)
else:
pgl.gluPerspective(
30.0, float(self.window.width)/float(self.window.height),
self.min_dist - 0.01, self.max_dist + 0.01)
pgl.glMatrixMode(pgl.GL_MODELVIEW)
def _get_scale(self):
return 1.0, 1.0, 1.0
def apply_transformation(self):
pgl.glLoadIdentity()
pgl.glTranslatef(self._x, self._y, -self._dist)
if self._rot is not None:
pgl.glMultMatrixf(self._rot)
pgl.glScalef(*self._get_scale())
def spherical_rotate(self, p1, p2, sensitivity=1.0):
mat = get_spherical_rotatation(p1, p2, self.window.width,
self.window.height, sensitivity)
if mat is not None:
self.mult_rot_matrix(mat)
def euler_rotate(self, angle, x, y, z):
pgl.glPushMatrix()
pgl.glLoadMatrixf(self._rot)
pgl.glRotatef(angle, x, y, z)
self._rot = get_model_matrix()
pgl.glPopMatrix()
def zoom_relative(self, clicks, sensitivity):
if self.ortho:
dist_d = clicks * sensitivity * 50.0
min_dist = self.min_ortho_dist
max_dist = self.max_ortho_dist
else:
dist_d = clicks * sensitivity
min_dist = self.min_dist
max_dist = self.max_dist
new_dist = (self._dist - dist_d)
if (clicks < 0 and new_dist < max_dist) or new_dist > min_dist:
self._dist = new_dist
def mouse_translate(self, x, y, dx, dy):
pgl.glPushMatrix()
pgl.glLoadIdentity()
pgl.glTranslatef(0, 0, -self._dist)
z = model_to_screen(0, 0, 0)[2]
d = vec_subs(screen_to_model(x, y, z), screen_to_model(x - dx, y - dy, z))
pgl.glPopMatrix()
self._x += d[0]
self._y += d[1]
PK ]ZZZ�)C , sympy/plotting/pygletplot/plot_controller.pyfrom pyglet.window import key
from pyglet.window.mouse import LEFT, RIGHT, MIDDLE
from sympy.plotting.pygletplot.util import get_direction_vectors, get_basis_vectors
class PlotController:
normal_mouse_sensitivity = 4.0
modified_mouse_sensitivity = 1.0
normal_key_sensitivity = 160.0
modified_key_sensitivity = 40.0
keymap = {
key.LEFT: 'left',
key.A: 'left',
key.NUM_4: 'left',
key.RIGHT: 'right',
key.D: 'right',
key.NUM_6: 'right',
key.UP: 'up',
key.W: 'up',
key.NUM_8: 'up',
key.DOWN: 'down',
key.S: 'down',
key.NUM_2: 'down',
key.Z: 'rotate_z_neg',
key.NUM_1: 'rotate_z_neg',
key.C: 'rotate_z_pos',
key.NUM_3: 'rotate_z_pos',
key.Q: 'spin_left',
key.NUM_7: 'spin_left',
key.E: 'spin_right',
key.NUM_9: 'spin_right',
key.X: 'reset_camera',
key.NUM_5: 'reset_camera',
key.NUM_ADD: 'zoom_in',
key.PAGEUP: 'zoom_in',
key.R: 'zoom_in',
key.NUM_SUBTRACT: 'zoom_out',
key.PAGEDOWN: 'zoom_out',
key.F: 'zoom_out',
key.RSHIFT: 'modify_sensitivity',
key.LSHIFT: 'modify_sensitivity',
key.F1: 'rot_preset_xy',
key.F2: 'rot_preset_xz',
key.F3: 'rot_preset_yz',
key.F4: 'rot_preset_perspective',
key.F5: 'toggle_axes',
key.F6: 'toggle_axe_colors',
key.F8: 'save_image'
}
def __init__(self, window, *, invert_mouse_zoom=False, **kwargs):
self.invert_mouse_zoom = invert_mouse_zoom
self.window = window
self.camera = window.camera
self.action = {
# Rotation around the view Y (up) vector
'left': False,
'right': False,
# Rotation around the view X vector
'up': False,
'down': False,
# Rotation around the view Z vector
'spin_left': False,
'spin_right': False,
# Rotation around the model Z vector
'rotate_z_neg': False,
'rotate_z_pos': False,
# Reset to the default rotation
'reset_camera': False,
# Performs camera z-translation
'zoom_in': False,
'zoom_out': False,
# Use alternative sensitivity (speed)
'modify_sensitivity': False,
# Rotation presets
'rot_preset_xy': False,
'rot_preset_xz': False,
'rot_preset_yz': False,
'rot_preset_perspective': False,
# axes
'toggle_axes': False,
'toggle_axe_colors': False,
# screenshot
'save_image': False
}
def update(self, dt):
z = 0
if self.action['zoom_out']:
z -= 1
if self.action['zoom_in']:
z += 1
if z != 0:
self.camera.zoom_relative(z/10.0, self.get_key_sensitivity()/10.0)
dx, dy, dz = 0, 0, 0
if self.action['left']:
dx -= 1
if self.action['right']:
dx += 1
if self.action['up']:
dy -= 1
if self.action['down']:
dy += 1
if self.action['spin_left']:
dz += 1
if self.action['spin_right']:
dz -= 1
if not self.is_2D():
if dx != 0:
self.camera.euler_rotate(dx*dt*self.get_key_sensitivity(),
*(get_direction_vectors()[1]))
if dy != 0:
self.camera.euler_rotate(dy*dt*self.get_key_sensitivity(),
*(get_direction_vectors()[0]))
if dz != 0:
self.camera.euler_rotate(dz*dt*self.get_key_sensitivity(),
*(get_direction_vectors()[2]))
else:
self.camera.mouse_translate(0, 0, dx*dt*self.get_key_sensitivity(),
-dy*dt*self.get_key_sensitivity())
rz = 0
if self.action['rotate_z_neg'] and not self.is_2D():
rz -= 1
if self.action['rotate_z_pos'] and not self.is_2D():
rz += 1
if rz != 0:
self.camera.euler_rotate(rz*dt*self.get_key_sensitivity(),
*(get_basis_vectors()[2]))
if self.action['reset_camera']:
self.camera.reset()
if self.action['rot_preset_xy']:
self.camera.set_rot_preset('xy')
if self.action['rot_preset_xz']:
self.camera.set_rot_preset('xz')
if self.action['rot_preset_yz']:
self.camera.set_rot_preset('yz')
if self.action['rot_preset_perspective']:
self.camera.set_rot_preset('perspective')
if self.action['toggle_axes']:
self.action['toggle_axes'] = False
self.camera.axes.toggle_visible()
if self.action['toggle_axe_colors']:
self.action['toggle_axe_colors'] = False
self.camera.axes.toggle_colors()
if self.action['save_image']:
self.action['save_image'] = False
self.window.plot.saveimage()
return True
def get_mouse_sensitivity(self):
if self.action['modify_sensitivity']:
return self.modified_mouse_sensitivity
else:
return self.normal_mouse_sensitivity
def get_key_sensitivity(self):
if self.action['modify_sensitivity']:
return self.modified_key_sensitivity
else:
return self.normal_key_sensitivity
def on_key_press(self, symbol, modifiers):
if symbol in self.keymap:
self.action[self.keymap[symbol]] = True
def on_key_release(self, symbol, modifiers):
if symbol in self.keymap:
self.action[self.keymap[symbol]] = False
def on_mouse_drag(self, x, y, dx, dy, buttons, modifiers):
if buttons & LEFT:
if self.is_2D():
self.camera.mouse_translate(x, y, dx, dy)
else:
self.camera.spherical_rotate((x - dx, y - dy), (x, y),
self.get_mouse_sensitivity())
if buttons & MIDDLE:
self.camera.zoom_relative([1, -1][self.invert_mouse_zoom]*dy,
self.get_mouse_sensitivity()/20.0)
if buttons & RIGHT:
self.camera.mouse_translate(x, y, dx, dy)
def on_mouse_scroll(self, x, y, dx, dy):
self.camera.zoom_relative([1, -1][self.invert_mouse_zoom]*dy,
self.get_mouse_sensitivity())
def is_2D(self):
functions = self.window.plot._functions
for i in functions:
if len(functions[i].i_vars) > 1 or len(functions[i].d_vars) > 2:
return False
return True
PK ]ZZZ�3Fn ' sympy/plotting/pygletplot/plot_curve.pyimport pyglet.gl as pgl
from sympy.core import S
from sympy.plotting.pygletplot.plot_mode_base import PlotModeBase
class PlotCurve(PlotModeBase):
style_override = 'wireframe'
def _on_calculate_verts(self):
self.t_interval = self.intervals[0]
self.t_set = list(self.t_interval.frange())
self.bounds = [[S.Infinity, S.NegativeInfinity, 0],
[S.Infinity, S.NegativeInfinity, 0],
[S.Infinity, S.NegativeInfinity, 0]]
evaluate = self._get_evaluator()
self._calculating_verts_pos = 0.0
self._calculating_verts_len = float(self.t_interval.v_len)
self.verts = []
b = self.bounds
for t in self.t_set:
try:
_e = evaluate(t) # calculate vertex
except (NameError, ZeroDivisionError):
_e = None
if _e is not None: # update bounding box
for axis in range(3):
b[axis][0] = min([b[axis][0], _e[axis]])
b[axis][1] = max([b[axis][1], _e[axis]])
self.verts.append(_e)
self._calculating_verts_pos += 1.0
for axis in range(3):
b[axis][2] = b[axis][1] - b[axis][0]
if b[axis][2] == 0.0:
b[axis][2] = 1.0
self.push_wireframe(self.draw_verts(False))
def _on_calculate_cverts(self):
if not self.verts or not self.color:
return
def set_work_len(n):
self._calculating_cverts_len = float(n)
def inc_work_pos():
self._calculating_cverts_pos += 1.0
set_work_len(1)
self._calculating_cverts_pos = 0
self.cverts = self.color.apply_to_curve(self.verts,
self.t_set,
set_len=set_work_len,
inc_pos=inc_work_pos)
self.push_wireframe(self.draw_verts(True))
def calculate_one_cvert(self, t):
vert = self.verts[t]
return self.color(vert[0], vert[1], vert[2],
self.t_set[t], None)
def draw_verts(self, use_cverts):
def f():
pgl.glBegin(pgl.GL_LINE_STRIP)
for t in range(len(self.t_set)):
p = self.verts[t]
if p is None:
pgl.glEnd()
pgl.glBegin(pgl.GL_LINE_STRIP)
continue
if use_cverts:
c = self.cverts[t]
if c is None:
c = (0, 0, 0)
pgl.glColor3f(*c)
else:
pgl.glColor3f(*self.default_wireframe_color)
pgl.glVertex3f(*p)
pgl.glEnd()
return f
PK ]ZZZ�a[7 7 * sympy/plotting/pygletplot/plot_interval.pyfrom sympy.core.singleton import S
from sympy.core.symbol import Symbol
from sympy.core.sympify import sympify
from sympy.core.numbers import Integer
class PlotInterval:
"""
"""
_v, _v_min, _v_max, _v_steps = None, None, None, None
def require_all_args(f):
def check(self, *args, **kwargs):
for g in [self._v, self._v_min, self._v_max, self._v_steps]:
if g is None:
raise ValueError("PlotInterval is incomplete.")
return f(self, *args, **kwargs)
return check
def __init__(self, *args):
if len(args) == 1:
if isinstance(args[0], PlotInterval):
self.fill_from(args[0])
return
elif isinstance(args[0], str):
try:
args = eval(args[0])
except TypeError:
s_eval_error = "Could not interpret string %s."
raise ValueError(s_eval_error % (args[0]))
elif isinstance(args[0], (tuple, list)):
args = args[0]
else:
raise ValueError("Not an interval.")
if not isinstance(args, (tuple, list)) or len(args) > 4:
f_error = "PlotInterval must be a tuple or list of length 4 or less."
raise ValueError(f_error)
args = list(args)
if len(args) > 0 and (args[0] is None or isinstance(args[0], Symbol)):
self.v = args.pop(0)
if len(args) in [2, 3]:
self.v_min = args.pop(0)
self.v_max = args.pop(0)
if len(args) == 1:
self.v_steps = args.pop(0)
elif len(args) == 1:
self.v_steps = args.pop(0)
def get_v(self):
return self._v
def set_v(self, v):
if v is None:
self._v = None
return
if not isinstance(v, Symbol):
raise ValueError("v must be a SymPy Symbol.")
self._v = v
def get_v_min(self):
return self._v_min
def set_v_min(self, v_min):
if v_min is None:
self._v_min = None
return
try:
self._v_min = sympify(v_min)
float(self._v_min.evalf())
except TypeError:
raise ValueError("v_min could not be interpreted as a number.")
def get_v_max(self):
return self._v_max
def set_v_max(self, v_max):
if v_max is None:
self._v_max = None
return
try:
self._v_max = sympify(v_max)
float(self._v_max.evalf())
except TypeError:
raise ValueError("v_max could not be interpreted as a number.")
def get_v_steps(self):
return self._v_steps
def set_v_steps(self, v_steps):
if v_steps is None:
self._v_steps = None
return
if isinstance(v_steps, int):
v_steps = Integer(v_steps)
elif not isinstance(v_steps, Integer):
raise ValueError("v_steps must be an int or SymPy Integer.")
if v_steps <= S.Zero:
raise ValueError("v_steps must be positive.")
self._v_steps = v_steps
@require_all_args
def get_v_len(self):
return self.v_steps + 1
v = property(get_v, set_v)
v_min = property(get_v_min, set_v_min)
v_max = property(get_v_max, set_v_max)
v_steps = property(get_v_steps, set_v_steps)
v_len = property(get_v_len)
def fill_from(self, b):
if b.v is not None:
self.v = b.v
if b.v_min is not None:
self.v_min = b.v_min
if b.v_max is not None:
self.v_max = b.v_max
if b.v_steps is not None:
self.v_steps = b.v_steps
@staticmethod
def try_parse(*args):
"""
Returns a PlotInterval if args can be interpreted
as such, otherwise None.
"""
if len(args) == 1 and isinstance(args[0], PlotInterval):
return args[0]
try:
return PlotInterval(*args)
except ValueError:
return None
def _str_base(self):
return ",".join([str(self.v), str(self.v_min),
str(self.v_max), str(self.v_steps)])
def __repr__(self):
"""
A string representing the interval in class constructor form.
"""
return "PlotInterval(%s)" % (self._str_base())
def __str__(self):
"""
A string representing the interval in list form.
"""
return "[%s]" % (self._str_base())
@require_all_args
def assert_complete(self):
pass
@require_all_args
def vrange(self):
"""
Yields v_steps+1 SymPy numbers ranging from
v_min to v_max.
"""
d = (self.v_max - self.v_min) / self.v_steps
for i in range(self.v_steps + 1):
a = self.v_min + (d * Integer(i))
yield a
@require_all_args
def vrange2(self):
"""
Yields v_steps pairs of SymPy numbers ranging from
(v_min, v_min + step) to (v_max - step, v_max).
"""
d = (self.v_max - self.v_min) / self.v_steps
a = self.v_min + (d * S.Zero)
for i in range(self.v_steps):
b = self.v_min + (d * Integer(i + 1))
yield a, b
a = b
def frange(self):
for i in self.vrange():
yield float(i.evalf())
PK ]ZZZ�2��L7 L7 & sympy/plotting/pygletplot/plot_mode.pyfrom .plot_interval import PlotInterval
from .plot_object import PlotObject
from .util import parse_option_string
from sympy.core.symbol import Symbol
from sympy.core.sympify import sympify
from sympy.geometry.entity import GeometryEntity
from sympy.utilities.iterables import is_sequence
class PlotMode(PlotObject):
"""
Grandparent class for plotting
modes. Serves as interface for
registration, lookup, and init
of modes.
To create a new plot mode,
inherit from PlotModeBase
or one of its children, such
as PlotSurface or PlotCurve.
"""
## Class-level attributes
## used to register and lookup
## plot modes. See PlotModeBase
## for descriptions and usage.
i_vars, d_vars = '', ''
intervals = []
aliases = []
is_default = False
## Draw is the only method here which
## is meant to be overridden in child
## classes, and PlotModeBase provides
## a base implementation.
def draw(self):
raise NotImplementedError()
## Everything else in this file has to
## do with registration and retrieval
## of plot modes. This is where I've
## hidden much of the ugliness of automatic
## plot mode divination...
## Plot mode registry data structures
_mode_alias_list = []
_mode_map = {
1: {1: {}, 2: {}},
2: {1: {}, 2: {}},
3: {1: {}, 2: {}},
} # [d][i][alias_str]: class
_mode_default_map = {
1: {},
2: {},
3: {},
} # [d][i]: class
_i_var_max, _d_var_max = 2, 3
def __new__(cls, *args, **kwargs):
"""
This is the function which interprets
arguments given to Plot.__init__ and
Plot.__setattr__. Returns an initialized
instance of the appropriate child class.
"""
newargs, newkwargs = PlotMode._extract_options(args, kwargs)
mode_arg = newkwargs.get('mode', '')
# Interpret the arguments
d_vars, intervals = PlotMode._interpret_args(newargs)
i_vars = PlotMode._find_i_vars(d_vars, intervals)
i, d = max([len(i_vars), len(intervals)]), len(d_vars)
# Find the appropriate mode
subcls = PlotMode._get_mode(mode_arg, i, d)
# Create the object
o = object.__new__(subcls)
# Do some setup for the mode instance
o.d_vars = d_vars
o._fill_i_vars(i_vars)
o._fill_intervals(intervals)
o.options = newkwargs
return o
@staticmethod
def _get_mode(mode_arg, i_var_count, d_var_count):
"""
Tries to return an appropriate mode class.
Intended to be called only by __new__.
mode_arg
Can be a string or a class. If it is a
PlotMode subclass, it is simply returned.
If it is a string, it can an alias for
a mode or an empty string. In the latter
case, we try to find a default mode for
the i_var_count and d_var_count.
i_var_count
The number of independent variables
needed to evaluate the d_vars.
d_var_count
The number of dependent variables;
usually the number of functions to
be evaluated in plotting.
For example, a Cartesian function y = f(x) has
one i_var (x) and one d_var (y). A parametric
form x,y,z = f(u,v), f(u,v), f(u,v) has two
two i_vars (u,v) and three d_vars (x,y,z).
"""
# if the mode_arg is simply a PlotMode class,
# check that the mode supports the numbers
# of independent and dependent vars, then
# return it
try:
m = None
if issubclass(mode_arg, PlotMode):
m = mode_arg
except TypeError:
pass
if m:
if not m._was_initialized:
raise ValueError(("To use unregistered plot mode %s "
"you must first call %s._init_mode().")
% (m.__name__, m.__name__))
if d_var_count != m.d_var_count:
raise ValueError(("%s can only plot functions "
"with %i dependent variables.")
% (m.__name__,
m.d_var_count))
if i_var_count > m.i_var_count:
raise ValueError(("%s cannot plot functions "
"with more than %i independent "
"variables.")
% (m.__name__,
m.i_var_count))
return m
# If it is a string, there are two possibilities.
if isinstance(mode_arg, str):
i, d = i_var_count, d_var_count
if i > PlotMode._i_var_max:
raise ValueError(var_count_error(True, True))
if d > PlotMode._d_var_max:
raise ValueError(var_count_error(False, True))
# If the string is '', try to find a suitable
# default mode
if not mode_arg:
return PlotMode._get_default_mode(i, d)
# Otherwise, interpret the string as a mode
# alias (e.g. 'cartesian', 'parametric', etc)
else:
return PlotMode._get_aliased_mode(mode_arg, i, d)
else:
raise ValueError("PlotMode argument must be "
"a class or a string")
@staticmethod
def _get_default_mode(i, d, i_vars=-1):
if i_vars == -1:
i_vars = i
try:
return PlotMode._mode_default_map[d][i]
except KeyError:
# Keep looking for modes in higher i var counts
# which support the given d var count until we
# reach the max i_var count.
if i < PlotMode._i_var_max:
return PlotMode._get_default_mode(i + 1, d, i_vars)
else:
raise ValueError(("Couldn't find a default mode "
"for %i independent and %i "
"dependent variables.") % (i_vars, d))
@staticmethod
def _get_aliased_mode(alias, i, d, i_vars=-1):
if i_vars == -1:
i_vars = i
if alias not in PlotMode._mode_alias_list:
raise ValueError(("Couldn't find a mode called"
" %s. Known modes: %s.")
% (alias, ", ".join(PlotMode._mode_alias_list)))
try:
return PlotMode._mode_map[d][i][alias]
except TypeError:
# Keep looking for modes in higher i var counts
# which support the given d var count and alias
# until we reach the max i_var count.
if i < PlotMode._i_var_max:
return PlotMode._get_aliased_mode(alias, i + 1, d, i_vars)
else:
raise ValueError(("Couldn't find a %s mode "
"for %i independent and %i "
"dependent variables.")
% (alias, i_vars, d))
@classmethod
def _register(cls):
"""
Called once for each user-usable plot mode.
For Cartesian2D, it is invoked after the
class definition: Cartesian2D._register()
"""
name = cls.__name__
cls._init_mode()
try:
i, d = cls.i_var_count, cls.d_var_count
# Add the mode to _mode_map under all
# given aliases
for a in cls.aliases:
if a not in PlotMode._mode_alias_list:
# Also track valid aliases, so
# we can quickly know when given
# an invalid one in _get_mode.
PlotMode._mode_alias_list.append(a)
PlotMode._mode_map[d][i][a] = cls
if cls.is_default:
# If this mode was marked as the
# default for this d,i combination,
# also set that.
PlotMode._mode_default_map[d][i] = cls
except Exception as e:
raise RuntimeError(("Failed to register "
"plot mode %s. Reason: %s")
% (name, (str(e))))
@classmethod
def _init_mode(cls):
"""
Initializes the plot mode based on
the 'mode-specific parameters' above.
Only intended to be called by
PlotMode._register(). To use a mode without
registering it, you can directly call
ModeSubclass._init_mode().
"""
def symbols_list(symbol_str):
return [Symbol(s) for s in symbol_str]
# Convert the vars strs into
# lists of symbols.
cls.i_vars = symbols_list(cls.i_vars)
cls.d_vars = symbols_list(cls.d_vars)
# Var count is used often, calculate
# it once here
cls.i_var_count = len(cls.i_vars)
cls.d_var_count = len(cls.d_vars)
if cls.i_var_count > PlotMode._i_var_max:
raise ValueError(var_count_error(True, False))
if cls.d_var_count > PlotMode._d_var_max:
raise ValueError(var_count_error(False, False))
# Try to use first alias as primary_alias
if len(cls.aliases) > 0:
cls.primary_alias = cls.aliases[0]
else:
cls.primary_alias = cls.__name__
di = cls.intervals
if len(di) != cls.i_var_count:
raise ValueError("Plot mode must provide a "
"default interval for each i_var.")
for i in range(cls.i_var_count):
# default intervals must be given [min,max,steps]
# (no var, but they must be in the same order as i_vars)
if len(di[i]) != 3:
raise ValueError("length should be equal to 3")
# Initialize an incomplete interval,
# to later be filled with a var when
# the mode is instantiated.
di[i] = PlotInterval(None, *di[i])
# To prevent people from using modes
# without these required fields set up.
cls._was_initialized = True
_was_initialized = False
## Initializer Helper Methods
@staticmethod
def _find_i_vars(functions, intervals):
i_vars = []
# First, collect i_vars in the
# order they are given in any
# intervals.
for i in intervals:
if i.v is None:
continue
elif i.v in i_vars:
raise ValueError(("Multiple intervals given "
"for %s.") % (str(i.v)))
i_vars.append(i.v)
# Then, find any remaining
# i_vars in given functions
# (aka d_vars)
for f in functions:
for a in f.free_symbols:
if a not in i_vars:
i_vars.append(a)
return i_vars
def _fill_i_vars(self, i_vars):
# copy default i_vars
self.i_vars = [Symbol(str(i)) for i in self.i_vars]
# replace with given i_vars
for i in range(len(i_vars)):
self.i_vars[i] = i_vars[i]
def _fill_intervals(self, intervals):
# copy default intervals
self.intervals = [PlotInterval(i) for i in self.intervals]
# track i_vars used so far
v_used = []
# fill copy of default
# intervals with given info
for i in range(len(intervals)):
self.intervals[i].fill_from(intervals[i])
if self.intervals[i].v is not None:
v_used.append(self.intervals[i].v)
# Find any orphan intervals and
# assign them i_vars
for i in range(len(self.intervals)):
if self.intervals[i].v is None:
u = [v for v in self.i_vars if v not in v_used]
if len(u) == 0:
raise ValueError("length should not be equal to 0")
self.intervals[i].v = u[0]
v_used.append(u[0])
@staticmethod
def _interpret_args(args):
interval_wrong_order = "PlotInterval %s was given before any function(s)."
interpret_error = "Could not interpret %s as a function or interval."
functions, intervals = [], []
if isinstance(args[0], GeometryEntity):
for coords in list(args[0].arbitrary_point()):
functions.append(coords)
intervals.append(PlotInterval.try_parse(args[0].plot_interval()))
else:
for a in args:
i = PlotInterval.try_parse(a)
if i is not None:
if len(functions) == 0:
raise ValueError(interval_wrong_order % (str(i)))
else:
intervals.append(i)
else:
if is_sequence(a, include=str):
raise ValueError(interpret_error % (str(a)))
try:
f = sympify(a)
functions.append(f)
except TypeError:
raise ValueError(interpret_error % str(a))
return functions, intervals
@staticmethod
def _extract_options(args, kwargs):
newkwargs, newargs = {}, []
for a in args:
if isinstance(a, str):
newkwargs = dict(newkwargs, **parse_option_string(a))
else:
newargs.append(a)
newkwargs = dict(newkwargs, **kwargs)
return newargs, newkwargs
def var_count_error(is_independent, is_plotting):
"""
Used to format an error message which differs
slightly in 4 places.
"""
if is_plotting:
v = "Plotting"
else:
v = "Registering plot modes"
if is_independent:
n, s = PlotMode._i_var_max, "independent"
else:
n, s = PlotMode._d_var_max, "dependent"
return ("%s with more than %i %s variables "
"is not supported.") % (v, n, s)
PK ]ZZZ�4{��, �, + sympy/plotting/pygletplot/plot_mode_base.pyimport pyglet.gl as pgl
from sympy.core import S
from sympy.plotting.pygletplot.color_scheme import ColorScheme
from sympy.plotting.pygletplot.plot_mode import PlotMode
from sympy.utilities.iterables import is_sequence
from time import sleep
from threading import Thread, Event, RLock
import warnings
class PlotModeBase(PlotMode):
"""
Intended parent class for plotting
modes. Provides base functionality
in conjunction with its parent,
PlotMode.
"""
##
## Class-Level Attributes
##
"""
The following attributes are meant
to be set at the class level, and serve
as parameters to the plot mode registry
(in PlotMode). See plot_modes.py for
concrete examples.
"""
"""
i_vars
'x' for Cartesian2D
'xy' for Cartesian3D
etc.
d_vars
'y' for Cartesian2D
'r' for Polar
etc.
"""
i_vars, d_vars = '', ''
"""
intervals
Default intervals for each i_var, and in the
same order. Specified [min, max, steps].
No variable can be given (it is bound later).
"""
intervals = []
"""
aliases
A list of strings which can be used to
access this mode.
'cartesian' for Cartesian2D and Cartesian3D
'polar' for Polar
'cylindrical', 'polar' for Cylindrical
Note that _init_mode chooses the first alias
in the list as the mode's primary_alias, which
will be displayed to the end user in certain
contexts.
"""
aliases = []
"""
is_default
Whether to set this mode as the default
for arguments passed to PlotMode() containing
the same number of d_vars as this mode and
at most the same number of i_vars.
"""
is_default = False
"""
All of the above attributes are defined in PlotMode.
The following ones are specific to PlotModeBase.
"""
"""
A list of the render styles. Do not modify.
"""
styles = {'wireframe': 1, 'solid': 2, 'both': 3}
"""
style_override
Always use this style if not blank.
"""
style_override = ''
"""
default_wireframe_color
default_solid_color
Can be used when color is None or being calculated.
Used by PlotCurve and PlotSurface, but not anywhere
in PlotModeBase.
"""
default_wireframe_color = (0.85, 0.85, 0.85)
default_solid_color = (0.6, 0.6, 0.9)
default_rot_preset = 'xy'
##
## Instance-Level Attributes
##
## 'Abstract' member functions
def _get_evaluator(self):
if self.use_lambda_eval:
try:
e = self._get_lambda_evaluator()
return e
except Exception:
warnings.warn("\nWarning: creating lambda evaluator failed. "
"Falling back on SymPy subs evaluator.")
return self._get_sympy_evaluator()
def _get_sympy_evaluator(self):
raise NotImplementedError()
def _get_lambda_evaluator(self):
raise NotImplementedError()
def _on_calculate_verts(self):
raise NotImplementedError()
def _on_calculate_cverts(self):
raise NotImplementedError()
## Base member functions
def __init__(self, *args, bounds_callback=None, **kwargs):
self.verts = []
self.cverts = []
self.bounds = [[S.Infinity, S.NegativeInfinity, 0],
[S.Infinity, S.NegativeInfinity, 0],
[S.Infinity, S.NegativeInfinity, 0]]
self.cbounds = [[S.Infinity, S.NegativeInfinity, 0],
[S.Infinity, S.NegativeInfinity, 0],
[S.Infinity, S.NegativeInfinity, 0]]
self._draw_lock = RLock()
self._calculating_verts = Event()
self._calculating_cverts = Event()
self._calculating_verts_pos = 0.0
self._calculating_verts_len = 0.0
self._calculating_cverts_pos = 0.0
self._calculating_cverts_len = 0.0
self._max_render_stack_size = 3
self._draw_wireframe = [-1]
self._draw_solid = [-1]
self._style = None
self._color = None
self.predraw = []
self.postdraw = []
self.use_lambda_eval = self.options.pop('use_sympy_eval', None) is None
self.style = self.options.pop('style', '')
self.color = self.options.pop('color', 'rainbow')
self.bounds_callback = bounds_callback
self._on_calculate()
def synchronized(f):
def w(self, *args, **kwargs):
self._draw_lock.acquire()
try:
r = f(self, *args, **kwargs)
return r
finally:
self._draw_lock.release()
return w
@synchronized
def push_wireframe(self, function):
"""
Push a function which performs gl commands
used to build a display list. (The list is
built outside of the function)
"""
assert callable(function)
self._draw_wireframe.append(function)
if len(self._draw_wireframe) > self._max_render_stack_size:
del self._draw_wireframe[1] # leave marker element
@synchronized
def push_solid(self, function):
"""
Push a function which performs gl commands
used to build a display list. (The list is
built outside of the function)
"""
assert callable(function)
self._draw_solid.append(function)
if len(self._draw_solid) > self._max_render_stack_size:
del self._draw_solid[1] # leave marker element
def _create_display_list(self, function):
dl = pgl.glGenLists(1)
pgl.glNewList(dl, pgl.GL_COMPILE)
function()
pgl.glEndList()
return dl
def _render_stack_top(self, render_stack):
top = render_stack[-1]
if top == -1:
return -1 # nothing to display
elif callable(top):
dl = self._create_display_list(top)
render_stack[-1] = (dl, top)
return dl # display newly added list
elif len(top) == 2:
if pgl.GL_TRUE == pgl.glIsList(top[0]):
return top[0] # display stored list
dl = self._create_display_list(top[1])
render_stack[-1] = (dl, top[1])
return dl # display regenerated list
def _draw_solid_display_list(self, dl):
pgl.glPushAttrib(pgl.GL_ENABLE_BIT | pgl.GL_POLYGON_BIT)
pgl.glPolygonMode(pgl.GL_FRONT_AND_BACK, pgl.GL_FILL)
pgl.glCallList(dl)
pgl.glPopAttrib()
def _draw_wireframe_display_list(self, dl):
pgl.glPushAttrib(pgl.GL_ENABLE_BIT | pgl.GL_POLYGON_BIT)
pgl.glPolygonMode(pgl.GL_FRONT_AND_BACK, pgl.GL_LINE)
pgl.glEnable(pgl.GL_POLYGON_OFFSET_LINE)
pgl.glPolygonOffset(-0.005, -50.0)
pgl.glCallList(dl)
pgl.glPopAttrib()
@synchronized
def draw(self):
for f in self.predraw:
if callable(f):
f()
if self.style_override:
style = self.styles[self.style_override]
else:
style = self.styles[self._style]
# Draw solid component if style includes solid
if style & 2:
dl = self._render_stack_top(self._draw_solid)
if dl > 0 and pgl.GL_TRUE == pgl.glIsList(dl):
self._draw_solid_display_list(dl)
# Draw wireframe component if style includes wireframe
if style & 1:
dl = self._render_stack_top(self._draw_wireframe)
if dl > 0 and pgl.GL_TRUE == pgl.glIsList(dl):
self._draw_wireframe_display_list(dl)
for f in self.postdraw:
if callable(f):
f()
def _on_change_color(self, color):
Thread(target=self._calculate_cverts).start()
def _on_calculate(self):
Thread(target=self._calculate_all).start()
def _calculate_all(self):
self._calculate_verts()
self._calculate_cverts()
def _calculate_verts(self):
if self._calculating_verts.is_set():
return
self._calculating_verts.set()
try:
self._on_calculate_verts()
finally:
self._calculating_verts.clear()
if callable(self.bounds_callback):
self.bounds_callback()
def _calculate_cverts(self):
if self._calculating_verts.is_set():
return
while self._calculating_cverts.is_set():
sleep(0) # wait for previous calculation
self._calculating_cverts.set()
try:
self._on_calculate_cverts()
finally:
self._calculating_cverts.clear()
def _get_calculating_verts(self):
return self._calculating_verts.is_set()
def _get_calculating_verts_pos(self):
return self._calculating_verts_pos
def _get_calculating_verts_len(self):
return self._calculating_verts_len
def _get_calculating_cverts(self):
return self._calculating_cverts.is_set()
def _get_calculating_cverts_pos(self):
return self._calculating_cverts_pos
def _get_calculating_cverts_len(self):
return self._calculating_cverts_len
## Property handlers
def _get_style(self):
return self._style
@synchronized
def _set_style(self, v):
if v is None:
return
if v == '':
step_max = 0
for i in self.intervals:
if i.v_steps is None:
continue
step_max = max([step_max, int(i.v_steps)])
v = ['both', 'solid'][step_max > 40]
if v not in self.styles:
raise ValueError("v should be there in self.styles")
if v == self._style:
return
self._style = v
def _get_color(self):
return self._color
@synchronized
def _set_color(self, v):
try:
if v is not None:
if is_sequence(v):
v = ColorScheme(*v)
else:
v = ColorScheme(v)
if repr(v) == repr(self._color):
return
self._on_change_color(v)
self._color = v
except Exception as e:
raise RuntimeError("Color change failed. "
"Reason: %s" % (str(e)))
style = property(_get_style, _set_style)
color = property(_get_color, _set_color)
calculating_verts = property(_get_calculating_verts)
calculating_verts_pos = property(_get_calculating_verts_pos)
calculating_verts_len = property(_get_calculating_verts_len)
calculating_cverts = property(_get_calculating_cverts)
calculating_cverts_pos = property(_get_calculating_cverts_pos)
calculating_cverts_len = property(_get_calculating_cverts_len)
## String representations
def __str__(self):
f = ", ".join(str(d) for d in self.d_vars)
o = "'mode=%s'" % (self.primary_alias)
return ", ".join([f, o])
def __repr__(self):
f = ", ".join(str(d) for d in self.d_vars)
i = ", ".join(str(i) for i in self.intervals)
d = [('mode', self.primary_alias),
('color', str(self.color)),
('style', str(self.style))]
o = "'%s'" % ("; ".join("%s=%s" % (k, v)
for k, v in d if v != 'None'))
return ", ".join([f, i, o])
PK ]ZZZ��3� � ' sympy/plotting/pygletplot/plot_modes.pyfrom sympy.utilities.lambdify import lambdify
from sympy.core.numbers import pi
from sympy.functions import sin, cos
from sympy.plotting.pygletplot.plot_curve import PlotCurve
from sympy.plotting.pygletplot.plot_surface import PlotSurface
from math import sin as p_sin
from math import cos as p_cos
def float_vec3(f):
def inner(*args):
v = f(*args)
return float(v[0]), float(v[1]), float(v[2])
return inner
class Cartesian2D(PlotCurve):
i_vars, d_vars = 'x', 'y'
intervals = [[-5, 5, 100]]
aliases = ['cartesian']
is_default = True
def _get_sympy_evaluator(self):
fy = self.d_vars[0]
x = self.t_interval.v
@float_vec3
def e(_x):
return (_x, fy.subs(x, _x), 0.0)
return e
def _get_lambda_evaluator(self):
fy = self.d_vars[0]
x = self.t_interval.v
return lambdify([x], [x, fy, 0.0])
class Cartesian3D(PlotSurface):
i_vars, d_vars = 'xy', 'z'
intervals = [[-1, 1, 40], [-1, 1, 40]]
aliases = ['cartesian', 'monge']
is_default = True
def _get_sympy_evaluator(self):
fz = self.d_vars[0]
x = self.u_interval.v
y = self.v_interval.v
@float_vec3
def e(_x, _y):
return (_x, _y, fz.subs(x, _x).subs(y, _y))
return e
def _get_lambda_evaluator(self):
fz = self.d_vars[0]
x = self.u_interval.v
y = self.v_interval.v
return lambdify([x, y], [x, y, fz])
class ParametricCurve2D(PlotCurve):
i_vars, d_vars = 't', 'xy'
intervals = [[0, 2*pi, 100]]
aliases = ['parametric']
is_default = True
def _get_sympy_evaluator(self):
fx, fy = self.d_vars
t = self.t_interval.v
@float_vec3
def e(_t):
return (fx.subs(t, _t), fy.subs(t, _t), 0.0)
return e
def _get_lambda_evaluator(self):
fx, fy = self.d_vars
t = self.t_interval.v
return lambdify([t], [fx, fy, 0.0])
class ParametricCurve3D(PlotCurve):
i_vars, d_vars = 't', 'xyz'
intervals = [[0, 2*pi, 100]]
aliases = ['parametric']
is_default = True
def _get_sympy_evaluator(self):
fx, fy, fz = self.d_vars
t = self.t_interval.v
@float_vec3
def e(_t):
return (fx.subs(t, _t), fy.subs(t, _t), fz.subs(t, _t))
return e
def _get_lambda_evaluator(self):
fx, fy, fz = self.d_vars
t = self.t_interval.v
return lambdify([t], [fx, fy, fz])
class ParametricSurface(PlotSurface):
i_vars, d_vars = 'uv', 'xyz'
intervals = [[-1, 1, 40], [-1, 1, 40]]
aliases = ['parametric']
is_default = True
def _get_sympy_evaluator(self):
fx, fy, fz = self.d_vars
u = self.u_interval.v
v = self.v_interval.v
@float_vec3
def e(_u, _v):
return (fx.subs(u, _u).subs(v, _v),
fy.subs(u, _u).subs(v, _v),
fz.subs(u, _u).subs(v, _v))
return e
def _get_lambda_evaluator(self):
fx, fy, fz = self.d_vars
u = self.u_interval.v
v = self.v_interval.v
return lambdify([u, v], [fx, fy, fz])
class Polar(PlotCurve):
i_vars, d_vars = 't', 'r'
intervals = [[0, 2*pi, 100]]
aliases = ['polar']
is_default = False
def _get_sympy_evaluator(self):
fr = self.d_vars[0]
t = self.t_interval.v
def e(_t):
_r = float(fr.subs(t, _t))
return (_r*p_cos(_t), _r*p_sin(_t), 0.0)
return e
def _get_lambda_evaluator(self):
fr = self.d_vars[0]
t = self.t_interval.v
fx, fy = fr*cos(t), fr*sin(t)
return lambdify([t], [fx, fy, 0.0])
class Cylindrical(PlotSurface):
i_vars, d_vars = 'th', 'r'
intervals = [[0, 2*pi, 40], [-1, 1, 20]]
aliases = ['cylindrical', 'polar']
is_default = False
def _get_sympy_evaluator(self):
fr = self.d_vars[0]
t = self.u_interval.v
h = self.v_interval.v
def e(_t, _h):
_r = float(fr.subs(t, _t).subs(h, _h))
return (_r*p_cos(_t), _r*p_sin(_t), _h)
return e
def _get_lambda_evaluator(self):
fr = self.d_vars[0]
t = self.u_interval.v
h = self.v_interval.v
fx, fy = fr*cos(t), fr*sin(t)
return lambdify([t, h], [fx, fy, h])
class Spherical(PlotSurface):
i_vars, d_vars = 'tp', 'r'
intervals = [[0, 2*pi, 40], [0, pi, 20]]
aliases = ['spherical']
is_default = False
def _get_sympy_evaluator(self):
fr = self.d_vars[0]
t = self.u_interval.v
p = self.v_interval.v
def e(_t, _p):
_r = float(fr.subs(t, _t).subs(p, _p))
return (_r*p_cos(_t)*p_sin(_p),
_r*p_sin(_t)*p_sin(_p),
_r*p_cos(_p))
return e
def _get_lambda_evaluator(self):
fr = self.d_vars[0]
t = self.u_interval.v
p = self.v_interval.v
fx = fr * cos(t) * sin(p)
fy = fr * sin(t) * sin(p)
fz = fr * cos(p)
return lambdify([t, p], [fx, fy, fz])
Cartesian2D._register()
Cartesian3D._register()
ParametricCurve2D._register()
ParametricCurve3D._register()
ParametricSurface._register()
Polar._register()
Cylindrical._register()
Spherical._register()
PK ]ZZZk� zJ J ( sympy/plotting/pygletplot/plot_object.pyclass PlotObject:
"""
Base class for objects which can be displayed in
a Plot.
"""
visible = True
def _draw(self):
if self.visible:
self.draw()
def draw(self):
"""
OpenGL rendering code for the plot object.
Override in base class.
"""
pass
PK ]ZZZ���ڧ � * sympy/plotting/pygletplot/plot_rotation.pytry:
from ctypes import c_float
except ImportError:
pass
import pyglet.gl as pgl
from math import sqrt as _sqrt, acos as _acos
def cross(a, b):
return (a[1] * b[2] - a[2] * b[1],
a[2] * b[0] - a[0] * b[2],
a[0] * b[1] - a[1] * b[0])
def dot(a, b):
return a[0] * b[0] + a[1] * b[1] + a[2] * b[2]
def mag(a):
return _sqrt(a[0]**2 + a[1]**2 + a[2]**2)
def norm(a):
m = mag(a)
return (a[0] / m, a[1] / m, a[2] / m)
def get_sphere_mapping(x, y, width, height):
x = min([max([x, 0]), width])
y = min([max([y, 0]), height])
sr = _sqrt((width/2)**2 + (height/2)**2)
sx = ((x - width / 2) / sr)
sy = ((y - height / 2) / sr)
sz = 1.0 - sx**2 - sy**2
if sz > 0.0:
sz = _sqrt(sz)
return (sx, sy, sz)
else:
sz = 0
return norm((sx, sy, sz))
rad2deg = 180.0 / 3.141592
def get_spherical_rotatation(p1, p2, width, height, theta_multiplier):
v1 = get_sphere_mapping(p1[0], p1[1], width, height)
v2 = get_sphere_mapping(p2[0], p2[1], width, height)
d = min(max([dot(v1, v2), -1]), 1)
if abs(d - 1.0) < 0.000001:
return None
raxis = norm( cross(v1, v2) )
rtheta = theta_multiplier * rad2deg * _acos(d)
pgl.glPushMatrix()
pgl.glLoadIdentity()
pgl.glRotatef(rtheta, *raxis)
mat = (c_float*16)()
pgl.glGetFloatv(pgl.GL_MODELVIEW_MATRIX, mat)
pgl.glPopMatrix()
return mat
PK ]ZZZ. �� � ) sympy/plotting/pygletplot/plot_surface.pyimport pyglet.gl as pgl
from sympy.core import S
from sympy.plotting.pygletplot.plot_mode_base import PlotModeBase
class PlotSurface(PlotModeBase):
default_rot_preset = 'perspective'
def _on_calculate_verts(self):
self.u_interval = self.intervals[0]
self.u_set = list(self.u_interval.frange())
self.v_interval = self.intervals[1]
self.v_set = list(self.v_interval.frange())
self.bounds = [[S.Infinity, S.NegativeInfinity, 0],
[S.Infinity, S.NegativeInfinity, 0],
[S.Infinity, S.NegativeInfinity, 0]]
evaluate = self._get_evaluator()
self._calculating_verts_pos = 0.0
self._calculating_verts_len = float(
self.u_interval.v_len*self.v_interval.v_len)
verts = []
b = self.bounds
for u in self.u_set:
column = []
for v in self.v_set:
try:
_e = evaluate(u, v) # calculate vertex
except ZeroDivisionError:
_e = None
if _e is not None: # update bounding box
for axis in range(3):
b[axis][0] = min([b[axis][0], _e[axis]])
b[axis][1] = max([b[axis][1], _e[axis]])
column.append(_e)
self._calculating_verts_pos += 1.0
verts.append(column)
for axis in range(3):
b[axis][2] = b[axis][1] - b[axis][0]
if b[axis][2] == 0.0:
b[axis][2] = 1.0
self.verts = verts
self.push_wireframe(self.draw_verts(False, False))
self.push_solid(self.draw_verts(False, True))
def _on_calculate_cverts(self):
if not self.verts or not self.color:
return
def set_work_len(n):
self._calculating_cverts_len = float(n)
def inc_work_pos():
self._calculating_cverts_pos += 1.0
set_work_len(1)
self._calculating_cverts_pos = 0
self.cverts = self.color.apply_to_surface(self.verts,
self.u_set,
self.v_set,
set_len=set_work_len,
inc_pos=inc_work_pos)
self.push_solid(self.draw_verts(True, True))
def calculate_one_cvert(self, u, v):
vert = self.verts[u][v]
return self.color(vert[0], vert[1], vert[2],
self.u_set[u], self.v_set[v])
def draw_verts(self, use_cverts, use_solid_color):
def f():
for u in range(1, len(self.u_set)):
pgl.glBegin(pgl.GL_QUAD_STRIP)
for v in range(len(self.v_set)):
pa = self.verts[u - 1][v]
pb = self.verts[u][v]
if pa is None or pb is None:
pgl.glEnd()
pgl.glBegin(pgl.GL_QUAD_STRIP)
continue
if use_cverts:
ca = self.cverts[u - 1][v]
cb = self.cverts[u][v]
if ca is None:
ca = (0, 0, 0)
if cb is None:
cb = (0, 0, 0)
else:
if use_solid_color:
ca = cb = self.default_solid_color
else:
ca = cb = self.default_wireframe_color
pgl.glColor3f(*ca)
pgl.glVertex3f(*pa)
pgl.glColor3f(*cb)
pgl.glVertex3f(*pb)
pgl.glEnd()
return f
PK ]ZZZ�2# # ( sympy/plotting/pygletplot/plot_window.pyfrom time import perf_counter
import pyglet.gl as pgl
from sympy.plotting.pygletplot.managed_window import ManagedWindow
from sympy.plotting.pygletplot.plot_camera import PlotCamera
from sympy.plotting.pygletplot.plot_controller import PlotController
class PlotWindow(ManagedWindow):
def __init__(self, plot, antialiasing=True, ortho=False,
invert_mouse_zoom=False, linewidth=1.5, caption="SymPy Plot",
**kwargs):
"""
Named Arguments
===============
antialiasing = True
True OR False
ortho = False
True OR False
invert_mouse_zoom = False
True OR False
"""
self.plot = plot
self.camera = None
self._calculating = False
self.antialiasing = antialiasing
self.ortho = ortho
self.invert_mouse_zoom = invert_mouse_zoom
self.linewidth = linewidth
self.title = caption
self.last_caption_update = 0
self.caption_update_interval = 0.2
self.drawing_first_object = True
super().__init__(**kwargs)
def setup(self):
self.camera = PlotCamera(self, ortho=self.ortho)
self.controller = PlotController(self,
invert_mouse_zoom=self.invert_mouse_zoom)
self.push_handlers(self.controller)
pgl.glClearColor(1.0, 1.0, 1.0, 0.0)
pgl.glClearDepth(1.0)
pgl.glDepthFunc(pgl.GL_LESS)
pgl.glEnable(pgl.GL_DEPTH_TEST)
pgl.glEnable(pgl.GL_LINE_SMOOTH)
pgl.glShadeModel(pgl.GL_SMOOTH)
pgl.glLineWidth(self.linewidth)
pgl.glEnable(pgl.GL_BLEND)
pgl.glBlendFunc(pgl.GL_SRC_ALPHA, pgl.GL_ONE_MINUS_SRC_ALPHA)
if self.antialiasing:
pgl.glHint(pgl.GL_LINE_SMOOTH_HINT, pgl.GL_NICEST)
pgl.glHint(pgl.GL_POLYGON_SMOOTH_HINT, pgl.GL_NICEST)
self.camera.setup_projection()
def on_resize(self, w, h):
super().on_resize(w, h)
if self.camera is not None:
self.camera.setup_projection()
def update(self, dt):
self.controller.update(dt)
def draw(self):
self.plot._render_lock.acquire()
self.camera.apply_transformation()
calc_verts_pos, calc_verts_len = 0, 0
calc_cverts_pos, calc_cverts_len = 0, 0
should_update_caption = (perf_counter() - self.last_caption_update >
self.caption_update_interval)
if len(self.plot._functions.values()) == 0:
self.drawing_first_object = True
iterfunctions = iter(self.plot._functions.values())
for r in iterfunctions:
if self.drawing_first_object:
self.camera.set_rot_preset(r.default_rot_preset)
self.drawing_first_object = False
pgl.glPushMatrix()
r._draw()
pgl.glPopMatrix()
# might as well do this while we are
# iterating and have the lock rather
# than locking and iterating twice
# per frame:
if should_update_caption:
try:
if r.calculating_verts:
calc_verts_pos += r.calculating_verts_pos
calc_verts_len += r.calculating_verts_len
if r.calculating_cverts:
calc_cverts_pos += r.calculating_cverts_pos
calc_cverts_len += r.calculating_cverts_len
except ValueError:
pass
for r in self.plot._pobjects:
pgl.glPushMatrix()
r._draw()
pgl.glPopMatrix()
if should_update_caption:
self.update_caption(calc_verts_pos, calc_verts_len,
calc_cverts_pos, calc_cverts_len)
self.last_caption_update = perf_counter()
if self.plot._screenshot:
self.plot._screenshot._execute_saving()
self.plot._render_lock.release()
def update_caption(self, calc_verts_pos, calc_verts_len,
calc_cverts_pos, calc_cverts_len):
caption = self.title
if calc_verts_len or calc_cverts_len:
caption += " (calculating"
if calc_verts_len > 0:
p = (calc_verts_pos / calc_verts_len) * 100
caption += " vertices %i%%" % (p)
if calc_cverts_len > 0:
p = (calc_cverts_pos / calc_cverts_len) * 100
caption += " colors %i%%" % (p)
caption += ")"
if self.caption != caption:
self.set_caption(caption)
PK ]ZZZ�ڇ�
! sympy/plotting/pygletplot/util.pytry:
from ctypes import c_float, c_int, c_double
except ImportError:
pass
import pyglet.gl as pgl
from sympy.core import S
def get_model_matrix(array_type=c_float, glGetMethod=pgl.glGetFloatv):
"""
Returns the current modelview matrix.
"""
m = (array_type*16)()
glGetMethod(pgl.GL_MODELVIEW_MATRIX, m)
return m
def get_projection_matrix(array_type=c_float, glGetMethod=pgl.glGetFloatv):
"""
Returns the current modelview matrix.
"""
m = (array_type*16)()
glGetMethod(pgl.GL_PROJECTION_MATRIX, m)
return m
def get_viewport():
"""
Returns the current viewport.
"""
m = (c_int*4)()
pgl.glGetIntegerv(pgl.GL_VIEWPORT, m)
return m
def get_direction_vectors():
m = get_model_matrix()
return ((m[0], m[4], m[8]),
(m[1], m[5], m[9]),
(m[2], m[6], m[10]))
def get_view_direction_vectors():
m = get_model_matrix()
return ((m[0], m[1], m[2]),
(m[4], m[5], m[6]),
(m[8], m[9], m[10]))
def get_basis_vectors():
return ((1, 0, 0), (0, 1, 0), (0, 0, 1))
def screen_to_model(x, y, z):
m = get_model_matrix(c_double, pgl.glGetDoublev)
p = get_projection_matrix(c_double, pgl.glGetDoublev)
w = get_viewport()
mx, my, mz = c_double(), c_double(), c_double()
pgl.gluUnProject(x, y, z, m, p, w, mx, my, mz)
return float(mx.value), float(my.value), float(mz.value)
def model_to_screen(x, y, z):
m = get_model_matrix(c_double, pgl.glGetDoublev)
p = get_projection_matrix(c_double, pgl.glGetDoublev)
w = get_viewport()
mx, my, mz = c_double(), c_double(), c_double()
pgl.gluProject(x, y, z, m, p, w, mx, my, mz)
return float(mx.value), float(my.value), float(mz.value)
def vec_subs(a, b):
return tuple(a[i] - b[i] for i in range(len(a)))
def billboard_matrix():
"""
Removes rotational components of
current matrix so that primitives
are always drawn facing the viewer.
|1|0|0|x|
|0|1|0|x|
|0|0|1|x| (x means left unchanged)
|x|x|x|x|
"""
m = get_model_matrix()
# XXX: for i in range(11): m[i] = i ?
m[0] = 1
m[1] = 0
m[2] = 0
m[4] = 0
m[5] = 1
m[6] = 0
m[8] = 0
m[9] = 0
m[10] = 1
pgl.glLoadMatrixf(m)
def create_bounds():
return [[S.Infinity, S.NegativeInfinity, 0],
[S.Infinity, S.NegativeInfinity, 0],
[S.Infinity, S.NegativeInfinity, 0]]
def update_bounds(b, v):
if v is None:
return
for axis in range(3):
b[axis][0] = min([b[axis][0], v[axis]])
b[axis][1] = max([b[axis][1], v[axis]])
def interpolate(a_min, a_max, a_ratio):
return a_min + a_ratio * (a_max - a_min)
def rinterpolate(a_min, a_max, a_value):
a_range = a_max - a_min
if a_max == a_min:
a_range = 1.0
return (a_value - a_min) / float(a_range)
def interpolate_color(color1, color2, ratio):
return tuple(interpolate(color1[i], color2[i], ratio) for i in range(3))
def scale_value(v, v_min, v_len):
return (v - v_min) / v_len
def scale_value_list(flist):
v_min, v_max = min(flist), max(flist)
v_len = v_max - v_min
return [scale_value(f, v_min, v_len) for f in flist]
def strided_range(r_min, r_max, stride, max_steps=50):
o_min, o_max = r_min, r_max
if abs(r_min - r_max) < 0.001:
return []
try:
range(int(r_min - r_max))
except (TypeError, OverflowError):
return []
if r_min > r_max:
raise ValueError("r_min cannot be greater than r_max")
r_min_s = (r_min % stride)
r_max_s = stride - (r_max % stride)
if abs(r_max_s - stride) < 0.001:
r_max_s = 0.0
r_min -= r_min_s
r_max += r_max_s
r_steps = int((r_max - r_min)/stride)
if max_steps and r_steps > max_steps:
return strided_range(o_min, o_max, stride*2)
return [r_min] + [r_min + e*stride for e in range(1, r_steps + 1)] + [r_max]
def parse_option_string(s):
if not isinstance(s, str):
return None
options = {}
for token in s.split(';'):
pieces = token.split('=')
if len(pieces) == 1:
option, value = pieces[0], ""
elif len(pieces) == 2:
option, value = pieces
else:
raise ValueError("Plot option string '%s' is malformed." % (s))
options[option.strip()] = value.strip()
return options
def dot_product(v1, v2):
return sum(v1[i]*v2[i] for i in range(3))
def vec_sub(v1, v2):
return tuple(v1[i] - v2[i] for i in range(3))
def vec_mag(v):
return sum(v[i]**2 for i in range(3))**(0.5)
PK ]ZZZ�ڬ�� � sympy/polys/__init__.py"""Polynomial manipulation algorithms and algebraic objects. """
__all__ = [
'Poly', 'PurePoly', 'poly_from_expr', 'parallel_poly_from_expr', 'degree',
'total_degree', 'degree_list', 'LC', 'LM', 'LT', 'pdiv', 'prem', 'pquo',
'pexquo', 'div', 'rem', 'quo', 'exquo', 'half_gcdex', 'gcdex', 'invert',
'subresultants', 'resultant', 'discriminant', 'cofactors', 'gcd_list',
'gcd', 'lcm_list', 'lcm', 'terms_gcd', 'trunc', 'monic', 'content',
'primitive', 'compose', 'decompose', 'sturm', 'gff_list', 'gff',
'sqf_norm', 'sqf_part', 'sqf_list', 'sqf', 'factor_list', 'factor',
'intervals', 'refine_root', 'count_roots', 'all_roots', 'real_roots',
'nroots', 'ground_roots', 'nth_power_roots_poly', 'cancel', 'reduced',
'groebner', 'is_zero_dimensional', 'GroebnerBasis', 'poly',
'symmetrize', 'horner', 'interpolate', 'rational_interpolate', 'viete',
'together',
'BasePolynomialError', 'ExactQuotientFailed', 'PolynomialDivisionFailed',
'OperationNotSupported', 'HeuristicGCDFailed', 'HomomorphismFailed',
'IsomorphismFailed', 'ExtraneousFactors', 'EvaluationFailed',
'RefinementFailed', 'CoercionFailed', 'NotInvertible', 'NotReversible',
'NotAlgebraic', 'DomainError', 'PolynomialError', 'UnificationFailed',
'GeneratorsError', 'GeneratorsNeeded', 'ComputationFailed',
'UnivariatePolynomialError', 'MultivariatePolynomialError',
'PolificationFailed', 'OptionError', 'FlagError',
'minpoly', 'minimal_polynomial', 'primitive_element', 'field_isomorphism',
'to_number_field', 'isolate', 'round_two', 'prime_decomp',
'prime_valuation', 'galois_group',
'itermonomials', 'Monomial',
'lex', 'grlex', 'grevlex', 'ilex', 'igrlex', 'igrevlex',
'CRootOf', 'rootof', 'RootOf', 'ComplexRootOf', 'RootSum',
'roots',
'Domain', 'FiniteField', 'IntegerRing', 'RationalField', 'RealField',
'ComplexField', 'PythonFiniteField', 'GMPYFiniteField',
'PythonIntegerRing', 'GMPYIntegerRing', 'PythonRational',
'GMPYRationalField', 'AlgebraicField', 'PolynomialRing', 'FractionField',
'ExpressionDomain', 'FF_python', 'FF_gmpy', 'ZZ_python', 'ZZ_gmpy',
'QQ_python', 'QQ_gmpy', 'GF', 'FF', 'ZZ', 'QQ', 'ZZ_I', 'QQ_I', 'RR',
'CC', 'EX', 'EXRAW',
'construct_domain',
'swinnerton_dyer_poly', 'cyclotomic_poly', 'symmetric_poly',
'random_poly', 'interpolating_poly',
'jacobi_poly', 'chebyshevt_poly', 'chebyshevu_poly', 'hermite_poly',
'hermite_prob_poly', 'legendre_poly', 'laguerre_poly',
'bernoulli_poly', 'bernoulli_c_poly', 'genocchi_poly', 'euler_poly',
'andre_poly',
'apart', 'apart_list', 'assemble_partfrac_list',
'Options',
'ring', 'xring', 'vring', 'sring',
'field', 'xfield', 'vfield', 'sfield'
]
from .polytools import (Poly, PurePoly, poly_from_expr,
parallel_poly_from_expr, degree, total_degree, degree_list, LC, LM,
LT, pdiv, prem, pquo, pexquo, div, rem, quo, exquo, half_gcdex, gcdex,
invert, subresultants, resultant, discriminant, cofactors, gcd_list,
gcd, lcm_list, lcm, terms_gcd, trunc, monic, content, primitive,
compose, decompose, sturm, gff_list, gff, sqf_norm, sqf_part,
sqf_list, sqf, factor_list, factor, intervals, refine_root,
count_roots, all_roots, real_roots, nroots, ground_roots,
nth_power_roots_poly, cancel, reduced, groebner, is_zero_dimensional,
GroebnerBasis, poly)
from .polyfuncs import (symmetrize, horner, interpolate,
rational_interpolate, viete)
from .rationaltools import together
from .polyerrors import (BasePolynomialError, ExactQuotientFailed,
PolynomialDivisionFailed, OperationNotSupported, HeuristicGCDFailed,
HomomorphismFailed, IsomorphismFailed, ExtraneousFactors,
EvaluationFailed, RefinementFailed, CoercionFailed, NotInvertible,
NotReversible, NotAlgebraic, DomainError, PolynomialError,
UnificationFailed, GeneratorsError, GeneratorsNeeded,
ComputationFailed, UnivariatePolynomialError,
MultivariatePolynomialError, PolificationFailed, OptionError,
FlagError)
from .numberfields import (minpoly, minimal_polynomial, primitive_element,
field_isomorphism, to_number_field, isolate, round_two, prime_decomp,
prime_valuation, galois_group)
from .monomials import itermonomials, Monomial
from .orderings import lex, grlex, grevlex, ilex, igrlex, igrevlex
from .rootoftools import CRootOf, rootof, RootOf, ComplexRootOf, RootSum
from .polyroots import roots
from .domains import (Domain, FiniteField, IntegerRing, RationalField,
RealField, ComplexField, PythonFiniteField, GMPYFiniteField,
PythonIntegerRing, GMPYIntegerRing, PythonRational, GMPYRationalField,
AlgebraicField, PolynomialRing, FractionField, ExpressionDomain,
FF_python, FF_gmpy, ZZ_python, ZZ_gmpy, QQ_python, QQ_gmpy, GF, FF,
ZZ, QQ, ZZ_I, QQ_I, RR, CC, EX, EXRAW)
from .constructor import construct_domain
from .specialpolys import (swinnerton_dyer_poly, cyclotomic_poly,
symmetric_poly, random_poly, interpolating_poly)
from .orthopolys import (jacobi_poly, chebyshevt_poly, chebyshevu_poly,
hermite_poly, hermite_prob_poly, legendre_poly, laguerre_poly)
from .appellseqs import (bernoulli_poly, bernoulli_c_poly, genocchi_poly,
euler_poly, andre_poly)
from .partfrac import apart, apart_list, assemble_partfrac_list
from .polyoptions import Options
from .rings import ring, xring, vring, sring
from .fields import field, xfield, vfield, sfield
PK ]ZZZB�UUq q sympy/polys/appellseqs.pyr"""
Efficient functions for generating Appell sequences.
An Appell sequence is a zero-indexed sequence of polynomials `p_i(x)`
satisfying `p_{i+1}'(x)=(i+1)p_i(x)` for all `i`. This definition leads
to the following iterative algorithm:
.. math :: p_0(x) = c_0,\ p_i(x) = i \int_0^x p_{i-1}(t)\,dt + c_i
The constant coefficients `c_i` are usually determined from the
just-evaluated integral and `i`.
Appell sequences satisfy the following identity from umbral calculus:
.. math :: p_n(x+y) = \sum_{k=0}^n \binom{n}{k} p_k(x) y^{n-k}
References
==========
.. [1] https://en.wikipedia.org/wiki/Appell_sequence
.. [2] Peter Luschny, "An introduction to the Bernoulli function",
https://arxiv.org/abs/2009.06743
"""
from sympy.polys.densearith import dup_mul_ground, dup_sub_ground, dup_quo_ground
from sympy.polys.densetools import dup_eval, dup_integrate
from sympy.polys.domains import ZZ, QQ
from sympy.polys.polytools import named_poly
from sympy.utilities import public
def dup_bernoulli(n, K):
"""Low-level implementation of Bernoulli polynomials."""
if n < 1:
return [K.one]
p = [K.one, K(-1,2)]
for i in range(2, n+1):
p = dup_integrate(dup_mul_ground(p, K(i), K), 1, K)
if i % 2 == 0:
p = dup_sub_ground(p, dup_eval(p, K(1,2), K) * K(1<<(i-1), (1<<i)-1), K)
return p
@public
def bernoulli_poly(n, x=None, polys=False):
r"""Generates the Bernoulli polynomial `\operatorname{B}_n(x)`.
`\operatorname{B}_n(x)` is the unique polynomial satisfying
.. math :: \int_{x}^{x+1} \operatorname{B}_n(t) \,dt = x^n.
Based on this, we have for nonnegative integer `s` and integer
`a` and `b`
.. math :: \sum_{k=a}^{b} k^s = \frac{\operatorname{B}_{s+1}(b+1) -
\operatorname{B}_{s+1}(a)}{s+1}
which is related to Jakob Bernoulli's original motivation for introducing
the Bernoulli numbers, the values of these polynomials at `x = 1`.
Examples
========
>>> from sympy import summation
>>> from sympy.abc import x
>>> from sympy.polys import bernoulli_poly
>>> bernoulli_poly(5, x)
x**5 - 5*x**4/2 + 5*x**3/3 - x/6
>>> def psum(p, a, b):
... return (bernoulli_poly(p+1,b+1) - bernoulli_poly(p+1,a)) / (p+1)
>>> psum(4, -6, 27)
3144337
>>> summation(x**4, (x, -6, 27))
3144337
>>> psum(1, 1, x).factor()
x*(x + 1)/2
>>> psum(2, 1, x).factor()
x*(x + 1)*(2*x + 1)/6
>>> psum(3, 1, x).factor()
x**2*(x + 1)**2/4
Parameters
==========
n : int
Degree of the polynomial.
x : optional
polys : bool, optional
If True, return a Poly, otherwise (default) return an expression.
See Also
========
sympy.functions.combinatorial.numbers.bernoulli
References
==========
.. [1] https://en.wikipedia.org/wiki/Bernoulli_polynomials
"""
return named_poly(n, dup_bernoulli, QQ, "Bernoulli polynomial", (x,), polys)
def dup_bernoulli_c(n, K):
"""Low-level implementation of central Bernoulli polynomials."""
p = [K.one]
for i in range(1, n+1):
p = dup_integrate(dup_mul_ground(p, K(i), K), 1, K)
if i % 2 == 0:
p = dup_sub_ground(p, dup_eval(p, K.one, K) * K((1<<(i-1))-1, (1<<i)-1), K)
return p
@public
def bernoulli_c_poly(n, x=None, polys=False):
r"""Generates the central Bernoulli polynomial `\operatorname{B}_n^c(x)`.
These are scaled and shifted versions of the plain Bernoulli polynomials,
done in such a way that `\operatorname{B}_n^c(x)` is an even or odd function
for even or odd `n` respectively:
.. math :: \operatorname{B}_n^c(x) = 2^n \operatorname{B}_n
\left(\frac{x+1}{2}\right)
Parameters
==========
n : int
Degree of the polynomial.
x : optional
polys : bool, optional
If True, return a Poly, otherwise (default) return an expression.
"""
return named_poly(n, dup_bernoulli_c, QQ, "central Bernoulli polynomial", (x,), polys)
def dup_genocchi(n, K):
"""Low-level implementation of Genocchi polynomials."""
if n < 1:
return [K.zero]
p = [-K.one]
for i in range(2, n+1):
p = dup_integrate(dup_mul_ground(p, K(i), K), 1, K)
if i % 2 == 0:
p = dup_sub_ground(p, dup_eval(p, K.one, K) // K(2), K)
return p
@public
def genocchi_poly(n, x=None, polys=False):
r"""Generates the Genocchi polynomial `\operatorname{G}_n(x)`.
`\operatorname{G}_n(x)` is twice the difference between the plain and
central Bernoulli polynomials, so has degree `n-1`:
.. math :: \operatorname{G}_n(x) = 2 (\operatorname{B}_n(x) -
\operatorname{B}_n^c(x))
The factor of 2 in the definition endows `\operatorname{G}_n(x)` with
integer coefficients.
Parameters
==========
n : int
Degree of the polynomial plus one.
x : optional
polys : bool, optional
If True, return a Poly, otherwise (default) return an expression.
See Also
========
sympy.functions.combinatorial.numbers.genocchi
"""
return named_poly(n, dup_genocchi, ZZ, "Genocchi polynomial", (x,), polys)
def dup_euler(n, K):
"""Low-level implementation of Euler polynomials."""
return dup_quo_ground(dup_genocchi(n+1, ZZ), K(-n-1), K)
@public
def euler_poly(n, x=None, polys=False):
r"""Generates the Euler polynomial `\operatorname{E}_n(x)`.
These are scaled and reindexed versions of the Genocchi polynomials:
.. math :: \operatorname{E}_n(x) = -\frac{\operatorname{G}_{n+1}(x)}{n+1}
Parameters
==========
n : int
Degree of the polynomial.
x : optional
polys : bool, optional
If True, return a Poly, otherwise (default) return an expression.
See Also
========
sympy.functions.combinatorial.numbers.euler
"""
return named_poly(n, dup_euler, QQ, "Euler polynomial", (x,), polys)
def dup_andre(n, K):
"""Low-level implementation of Andre polynomials."""
p = [K.one]
for i in range(1, n+1):
p = dup_integrate(dup_mul_ground(p, K(i), K), 1, K)
if i % 2 == 0:
p = dup_sub_ground(p, dup_eval(p, K.one, K), K)
return p
@public
def andre_poly(n, x=None, polys=False):
r"""Generates the Andre polynomial `\mathcal{A}_n(x)`.
This is the Appell sequence where the constant coefficients form the sequence
of Euler numbers ``euler(n)``. As such they have integer coefficients
and parities matching the parity of `n`.
Luschny calls these the *Swiss-knife polynomials* because their values
at 0 and 1 can be simply transformed into both the Bernoulli and Euler
numbers. Here they are called the Andre polynomials because
`|\mathcal{A}_n(n\bmod 2)|` for `n \ge 0` generates what Luschny calls
the *Andre numbers*, A000111 in the OEIS.
Examples
========
>>> from sympy import bernoulli, euler, genocchi
>>> from sympy.abc import x
>>> from sympy.polys import andre_poly
>>> andre_poly(9, x)
x**9 - 36*x**7 + 630*x**5 - 5124*x**3 + 12465*x
>>> [andre_poly(n, 0) for n in range(11)]
[1, 0, -1, 0, 5, 0, -61, 0, 1385, 0, -50521]
>>> [euler(n) for n in range(11)]
[1, 0, -1, 0, 5, 0, -61, 0, 1385, 0, -50521]
>>> [andre_poly(n-1, 1) * n / (4**n - 2**n) for n in range(1, 11)]
[1/2, 1/6, 0, -1/30, 0, 1/42, 0, -1/30, 0, 5/66]
>>> [bernoulli(n) for n in range(1, 11)]
[1/2, 1/6, 0, -1/30, 0, 1/42, 0, -1/30, 0, 5/66]
>>> [-andre_poly(n-1, -1) * n / (-2)**(n-1) for n in range(1, 11)]
[-1, -1, 0, 1, 0, -3, 0, 17, 0, -155]
>>> [genocchi(n) for n in range(1, 11)]
[-1, -1, 0, 1, 0, -3, 0, 17, 0, -155]
>>> [abs(andre_poly(n, n%2)) for n in range(11)]
[1, 1, 1, 2, 5, 16, 61, 272, 1385, 7936, 50521]
Parameters
==========
n : int
Degree of the polynomial.
x : optional
polys : bool, optional
If True, return a Poly, otherwise (default) return an expression.
See Also
========
sympy.functions.combinatorial.numbers.andre
References
==========
.. [1] Peter Luschny, "An introduction to the Bernoulli function",
https://arxiv.org/abs/2009.06743
"""
return named_poly(n, dup_andre, ZZ, "Andre polynomial", (x,), polys)
PK ]ZZZ`*��� �� sympy/polys/compatibility.py"""Compatibility interface between dense and sparse polys. """
from sympy.polys.densearith import dup_add_term
from sympy.polys.densearith import dmp_add_term
from sympy.polys.densearith import dup_sub_term
from sympy.polys.densearith import dmp_sub_term
from sympy.polys.densearith import dup_mul_term
from sympy.polys.densearith import dmp_mul_term
from sympy.polys.densearith import dup_add_ground
from sympy.polys.densearith import dmp_add_ground
from sympy.polys.densearith import dup_sub_ground
from sympy.polys.densearith import dmp_sub_ground
from sympy.polys.densearith import dup_mul_ground
from sympy.polys.densearith import dmp_mul_ground
from sympy.polys.densearith import dup_quo_ground
from sympy.polys.densearith import dmp_quo_ground
from sympy.polys.densearith import dup_exquo_ground
from sympy.polys.densearith import dmp_exquo_ground
from sympy.polys.densearith import dup_lshift
from sympy.polys.densearith import dup_rshift
from sympy.polys.densearith import dup_abs
from sympy.polys.densearith import dmp_abs
from sympy.polys.densearith import dup_neg
from sympy.polys.densearith import dmp_neg
from sympy.polys.densearith import dup_add
from sympy.polys.densearith import dmp_add
from sympy.polys.densearith import dup_sub
from sympy.polys.densearith import dmp_sub
from sympy.polys.densearith import dup_add_mul
from sympy.polys.densearith import dmp_add_mul
from sympy.polys.densearith import dup_sub_mul
from sympy.polys.densearith import dmp_sub_mul
from sympy.polys.densearith import dup_mul
from sympy.polys.densearith import dmp_mul
from sympy.polys.densearith import dup_sqr
from sympy.polys.densearith import dmp_sqr
from sympy.polys.densearith import dup_pow
from sympy.polys.densearith import dmp_pow
from sympy.polys.densearith import dup_pdiv
from sympy.polys.densearith import dup_prem
from sympy.polys.densearith import dup_pquo
from sympy.polys.densearith import dup_pexquo
from sympy.polys.densearith import dmp_pdiv
from sympy.polys.densearith import dmp_prem
from sympy.polys.densearith import dmp_pquo
from sympy.polys.densearith import dmp_pexquo
from sympy.polys.densearith import dup_rr_div
from sympy.polys.densearith import dmp_rr_div
from sympy.polys.densearith import dup_ff_div
from sympy.polys.densearith import dmp_ff_div
from sympy.polys.densearith import dup_div
from sympy.polys.densearith import dup_rem
from sympy.polys.densearith import dup_quo
from sympy.polys.densearith import dup_exquo
from sympy.polys.densearith import dmp_div
from sympy.polys.densearith import dmp_rem
from sympy.polys.densearith import dmp_quo
from sympy.polys.densearith import dmp_exquo
from sympy.polys.densearith import dup_max_norm
from sympy.polys.densearith import dmp_max_norm
from sympy.polys.densearith import dup_l1_norm
from sympy.polys.densearith import dmp_l1_norm
from sympy.polys.densearith import dup_l2_norm_squared
from sympy.polys.densearith import dmp_l2_norm_squared
from sympy.polys.densearith import dup_expand
from sympy.polys.densearith import dmp_expand
from sympy.polys.densebasic import dup_LC
from sympy.polys.densebasic import dmp_LC
from sympy.polys.densebasic import dup_TC
from sympy.polys.densebasic import dmp_TC
from sympy.polys.densebasic import dmp_ground_LC
from sympy.polys.densebasic import dmp_ground_TC
from sympy.polys.densebasic import dup_degree
from sympy.polys.densebasic import dmp_degree
from sympy.polys.densebasic import dmp_degree_in
from sympy.polys.densebasic import dmp_to_dict
from sympy.polys.densetools import dup_integrate
from sympy.polys.densetools import dmp_integrate
from sympy.polys.densetools import dmp_integrate_in
from sympy.polys.densetools import dup_diff
from sympy.polys.densetools import dmp_diff
from sympy.polys.densetools import dmp_diff_in
from sympy.polys.densetools import dup_eval
from sympy.polys.densetools import dmp_eval
from sympy.polys.densetools import dmp_eval_in
from sympy.polys.densetools import dmp_eval_tail
from sympy.polys.densetools import dmp_diff_eval_in
from sympy.polys.densetools import dup_trunc
from sympy.polys.densetools import dmp_trunc
from sympy.polys.densetools import dmp_ground_trunc
from sympy.polys.densetools import dup_monic
from sympy.polys.densetools import dmp_ground_monic
from sympy.polys.densetools import dup_content
from sympy.polys.densetools import dmp_ground_content
from sympy.polys.densetools import dup_primitive
from sympy.polys.densetools import dmp_ground_primitive
from sympy.polys.densetools import dup_extract
from sympy.polys.densetools import dmp_ground_extract
from sympy.polys.densetools import dup_real_imag
from sympy.polys.densetools import dup_mirror
from sympy.polys.densetools import dup_scale
from sympy.polys.densetools import dup_shift
from sympy.polys.densetools import dmp_shift
from sympy.polys.densetools import dup_transform
from sympy.polys.densetools import dup_compose
from sympy.polys.densetools import dmp_compose
from sympy.polys.densetools import dup_decompose
from sympy.polys.densetools import dmp_lift
from sympy.polys.densetools import dup_sign_variations
from sympy.polys.densetools import dup_clear_denoms
from sympy.polys.densetools import dmp_clear_denoms
from sympy.polys.densetools import dup_revert
from sympy.polys.euclidtools import dup_half_gcdex
from sympy.polys.euclidtools import dmp_half_gcdex
from sympy.polys.euclidtools import dup_gcdex
from sympy.polys.euclidtools import dmp_gcdex
from sympy.polys.euclidtools import dup_invert
from sympy.polys.euclidtools import dmp_invert
from sympy.polys.euclidtools import dup_euclidean_prs
from sympy.polys.euclidtools import dmp_euclidean_prs
from sympy.polys.euclidtools import dup_primitive_prs
from sympy.polys.euclidtools import dmp_primitive_prs
from sympy.polys.euclidtools import dup_inner_subresultants
from sympy.polys.euclidtools import dup_subresultants
from sympy.polys.euclidtools import dup_prs_resultant
from sympy.polys.euclidtools import dup_resultant
from sympy.polys.euclidtools import dmp_inner_subresultants
from sympy.polys.euclidtools import dmp_subresultants
from sympy.polys.euclidtools import dmp_prs_resultant
from sympy.polys.euclidtools import dmp_zz_modular_resultant
from sympy.polys.euclidtools import dmp_zz_collins_resultant
from sympy.polys.euclidtools import dmp_qq_collins_resultant
from sympy.polys.euclidtools import dmp_resultant
from sympy.polys.euclidtools import dup_discriminant
from sympy.polys.euclidtools import dmp_discriminant
from sympy.polys.euclidtools import dup_rr_prs_gcd
from sympy.polys.euclidtools import dup_ff_prs_gcd
from sympy.polys.euclidtools import dmp_rr_prs_gcd
from sympy.polys.euclidtools import dmp_ff_prs_gcd
from sympy.polys.euclidtools import dup_zz_heu_gcd
from sympy.polys.euclidtools import dmp_zz_heu_gcd
from sympy.polys.euclidtools import dup_qq_heu_gcd
from sympy.polys.euclidtools import dmp_qq_heu_gcd
from sympy.polys.euclidtools import dup_inner_gcd
from sympy.polys.euclidtools import dmp_inner_gcd
from sympy.polys.euclidtools import dup_gcd
from sympy.polys.euclidtools import dmp_gcd
from sympy.polys.euclidtools import dup_rr_lcm
from sympy.polys.euclidtools import dup_ff_lcm
from sympy.polys.euclidtools import dup_lcm
from sympy.polys.euclidtools import dmp_rr_lcm
from sympy.polys.euclidtools import dmp_ff_lcm
from sympy.polys.euclidtools import dmp_lcm
from sympy.polys.euclidtools import dmp_content
from sympy.polys.euclidtools import dmp_primitive
from sympy.polys.euclidtools import dup_cancel
from sympy.polys.euclidtools import dmp_cancel
from sympy.polys.factortools import dup_trial_division
from sympy.polys.factortools import dmp_trial_division
from sympy.polys.factortools import dup_zz_mignotte_bound
from sympy.polys.factortools import dmp_zz_mignotte_bound
from sympy.polys.factortools import dup_zz_hensel_step
from sympy.polys.factortools import dup_zz_hensel_lift
from sympy.polys.factortools import dup_zz_zassenhaus
from sympy.polys.factortools import dup_zz_irreducible_p
from sympy.polys.factortools import dup_cyclotomic_p
from sympy.polys.factortools import dup_zz_cyclotomic_poly
from sympy.polys.factortools import dup_zz_cyclotomic_factor
from sympy.polys.factortools import dup_zz_factor_sqf
from sympy.polys.factortools import dup_zz_factor
from sympy.polys.factortools import dmp_zz_wang_non_divisors
from sympy.polys.factortools import dmp_zz_wang_lead_coeffs
from sympy.polys.factortools import dup_zz_diophantine
from sympy.polys.factortools import dmp_zz_diophantine
from sympy.polys.factortools import dmp_zz_wang_hensel_lifting
from sympy.polys.factortools import dmp_zz_wang
from sympy.polys.factortools import dmp_zz_factor
from sympy.polys.factortools import dup_qq_i_factor
from sympy.polys.factortools import dup_zz_i_factor
from sympy.polys.factortools import dmp_qq_i_factor
from sympy.polys.factortools import dmp_zz_i_factor
from sympy.polys.factortools import dup_ext_factor
from sympy.polys.factortools import dmp_ext_factor
from sympy.polys.factortools import dup_gf_factor
from sympy.polys.factortools import dmp_gf_factor
from sympy.polys.factortools import dup_factor_list
from sympy.polys.factortools import dup_factor_list_include
from sympy.polys.factortools import dmp_factor_list
from sympy.polys.factortools import dmp_factor_list_include
from sympy.polys.factortools import dup_irreducible_p
from sympy.polys.factortools import dmp_irreducible_p
from sympy.polys.rootisolation import dup_sturm
from sympy.polys.rootisolation import dup_root_upper_bound
from sympy.polys.rootisolation import dup_root_lower_bound
from sympy.polys.rootisolation import dup_step_refine_real_root
from sympy.polys.rootisolation import dup_inner_refine_real_root
from sympy.polys.rootisolation import dup_outer_refine_real_root
from sympy.polys.rootisolation import dup_refine_real_root
from sympy.polys.rootisolation import dup_inner_isolate_real_roots
from sympy.polys.rootisolation import dup_inner_isolate_positive_roots
from sympy.polys.rootisolation import dup_inner_isolate_negative_roots
from sympy.polys.rootisolation import dup_isolate_real_roots_sqf
from sympy.polys.rootisolation import dup_isolate_real_roots
from sympy.polys.rootisolation import dup_isolate_real_roots_list
from sympy.polys.rootisolation import dup_count_real_roots
from sympy.polys.rootisolation import dup_count_complex_roots
from sympy.polys.rootisolation import dup_isolate_complex_roots_sqf
from sympy.polys.rootisolation import dup_isolate_all_roots_sqf
from sympy.polys.rootisolation import dup_isolate_all_roots
from sympy.polys.sqfreetools import (
dup_sqf_p, dmp_sqf_p, dmp_norm, dup_sqf_norm, dmp_sqf_norm,
dup_gf_sqf_part, dmp_gf_sqf_part, dup_sqf_part, dmp_sqf_part,
dup_gf_sqf_list, dmp_gf_sqf_list, dup_sqf_list, dup_sqf_list_include,
dmp_sqf_list, dmp_sqf_list_include, dup_gff_list, dmp_gff_list)
from sympy.polys.galoistools import (
gf_degree, gf_LC, gf_TC, gf_strip, gf_from_dict,
gf_to_dict, gf_from_int_poly, gf_to_int_poly, gf_neg, gf_add_ground, gf_sub_ground,
gf_mul_ground, gf_quo_ground, gf_add, gf_sub, gf_mul, gf_sqr, gf_add_mul, gf_sub_mul,
gf_expand, gf_div, gf_rem, gf_quo, gf_exquo, gf_lshift, gf_rshift, gf_pow, gf_pow_mod,
gf_gcd, gf_lcm, gf_cofactors, gf_gcdex, gf_monic, gf_diff, gf_eval, gf_multi_eval,
gf_compose, gf_compose_mod, gf_trace_map, gf_random, gf_irreducible, gf_irred_p_ben_or,
gf_irred_p_rabin, gf_irreducible_p, gf_sqf_p, gf_sqf_part, gf_Qmatrix,
gf_berlekamp, gf_ddf_zassenhaus, gf_edf_zassenhaus, gf_ddf_shoup, gf_edf_shoup,
gf_zassenhaus, gf_shoup, gf_factor_sqf, gf_factor)
from sympy.utilities import public
@public
class IPolys:
symbols = None
ngens = None
domain = None
order = None
gens = None
def drop(self, gen):
pass
def clone(self, symbols=None, domain=None, order=None):
pass
def to_ground(self):
pass
def ground_new(self, element):
pass
def domain_new(self, element):
pass
def from_dict(self, d):
pass
def wrap(self, element):
from sympy.polys.rings import PolyElement
if isinstance(element, PolyElement):
if element.ring == self:
return element
else:
raise NotImplementedError("domain conversions")
else:
return self.ground_new(element)
def to_dense(self, element):
return self.wrap(element).to_dense()
def from_dense(self, element):
return self.from_dict(dmp_to_dict(element, self.ngens-1, self.domain))
def dup_add_term(self, f, c, i):
return self.from_dense(dup_add_term(self.to_dense(f), c, i, self.domain))
def dmp_add_term(self, f, c, i):
return self.from_dense(dmp_add_term(self.to_dense(f), self.wrap(c).drop(0).to_dense(), i, self.ngens-1, self.domain))
def dup_sub_term(self, f, c, i):
return self.from_dense(dup_sub_term(self.to_dense(f), c, i, self.domain))
def dmp_sub_term(self, f, c, i):
return self.from_dense(dmp_sub_term(self.to_dense(f), self.wrap(c).drop(0).to_dense(), i, self.ngens-1, self.domain))
def dup_mul_term(self, f, c, i):
return self.from_dense(dup_mul_term(self.to_dense(f), c, i, self.domain))
def dmp_mul_term(self, f, c, i):
return self.from_dense(dmp_mul_term(self.to_dense(f), self.wrap(c).drop(0).to_dense(), i, self.ngens-1, self.domain))
def dup_add_ground(self, f, c):
return self.from_dense(dup_add_ground(self.to_dense(f), c, self.domain))
def dmp_add_ground(self, f, c):
return self.from_dense(dmp_add_ground(self.to_dense(f), c, self.ngens-1, self.domain))
def dup_sub_ground(self, f, c):
return self.from_dense(dup_sub_ground(self.to_dense(f), c, self.domain))
def dmp_sub_ground(self, f, c):
return self.from_dense(dmp_sub_ground(self.to_dense(f), c, self.ngens-1, self.domain))
def dup_mul_ground(self, f, c):
return self.from_dense(dup_mul_ground(self.to_dense(f), c, self.domain))
def dmp_mul_ground(self, f, c):
return self.from_dense(dmp_mul_ground(self.to_dense(f), c, self.ngens-1, self.domain))
def dup_quo_ground(self, f, c):
return self.from_dense(dup_quo_ground(self.to_dense(f), c, self.domain))
def dmp_quo_ground(self, f, c):
return self.from_dense(dmp_quo_ground(self.to_dense(f), c, self.ngens-1, self.domain))
def dup_exquo_ground(self, f, c):
return self.from_dense(dup_exquo_ground(self.to_dense(f), c, self.domain))
def dmp_exquo_ground(self, f, c):
return self.from_dense(dmp_exquo_ground(self.to_dense(f), c, self.ngens-1, self.domain))
def dup_lshift(self, f, n):
return self.from_dense(dup_lshift(self.to_dense(f), n, self.domain))
def dup_rshift(self, f, n):
return self.from_dense(dup_rshift(self.to_dense(f), n, self.domain))
def dup_abs(self, f):
return self.from_dense(dup_abs(self.to_dense(f), self.domain))
def dmp_abs(self, f):
return self.from_dense(dmp_abs(self.to_dense(f), self.ngens-1, self.domain))
def dup_neg(self, f):
return self.from_dense(dup_neg(self.to_dense(f), self.domain))
def dmp_neg(self, f):
return self.from_dense(dmp_neg(self.to_dense(f), self.ngens-1, self.domain))
def dup_add(self, f, g):
return self.from_dense(dup_add(self.to_dense(f), self.to_dense(g), self.domain))
def dmp_add(self, f, g):
return self.from_dense(dmp_add(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain))
def dup_sub(self, f, g):
return self.from_dense(dup_sub(self.to_dense(f), self.to_dense(g), self.domain))
def dmp_sub(self, f, g):
return self.from_dense(dmp_sub(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain))
def dup_add_mul(self, f, g, h):
return self.from_dense(dup_add_mul(self.to_dense(f), self.to_dense(g), self.to_dense(h), self.domain))
def dmp_add_mul(self, f, g, h):
return self.from_dense(dmp_add_mul(self.to_dense(f), self.to_dense(g), self.to_dense(h), self.ngens-1, self.domain))
def dup_sub_mul(self, f, g, h):
return self.from_dense(dup_sub_mul(self.to_dense(f), self.to_dense(g), self.to_dense(h), self.domain))
def dmp_sub_mul(self, f, g, h):
return self.from_dense(dmp_sub_mul(self.to_dense(f), self.to_dense(g), self.to_dense(h), self.ngens-1, self.domain))
def dup_mul(self, f, g):
return self.from_dense(dup_mul(self.to_dense(f), self.to_dense(g), self.domain))
def dmp_mul(self, f, g):
return self.from_dense(dmp_mul(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain))
def dup_sqr(self, f):
return self.from_dense(dup_sqr(self.to_dense(f), self.domain))
def dmp_sqr(self, f):
return self.from_dense(dmp_sqr(self.to_dense(f), self.ngens-1, self.domain))
def dup_pow(self, f, n):
return self.from_dense(dup_pow(self.to_dense(f), n, self.domain))
def dmp_pow(self, f, n):
return self.from_dense(dmp_pow(self.to_dense(f), n, self.ngens-1, self.domain))
def dup_pdiv(self, f, g):
q, r = dup_pdiv(self.to_dense(f), self.to_dense(g), self.domain)
return (self.from_dense(q), self.from_dense(r))
def dup_prem(self, f, g):
return self.from_dense(dup_prem(self.to_dense(f), self.to_dense(g), self.domain))
def dup_pquo(self, f, g):
return self.from_dense(dup_pquo(self.to_dense(f), self.to_dense(g), self.domain))
def dup_pexquo(self, f, g):
return self.from_dense(dup_pexquo(self.to_dense(f), self.to_dense(g), self.domain))
def dmp_pdiv(self, f, g):
q, r = dmp_pdiv(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain)
return (self.from_dense(q), self.from_dense(r))
def dmp_prem(self, f, g):
return self.from_dense(dmp_prem(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain))
def dmp_pquo(self, f, g):
return self.from_dense(dmp_pquo(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain))
def dmp_pexquo(self, f, g):
return self.from_dense(dmp_pexquo(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain))
def dup_rr_div(self, f, g):
q, r = dup_rr_div(self.to_dense(f), self.to_dense(g), self.domain)
return (self.from_dense(q), self.from_dense(r))
def dmp_rr_div(self, f, g):
q, r = dmp_rr_div(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain)
return (self.from_dense(q), self.from_dense(r))
def dup_ff_div(self, f, g):
q, r = dup_ff_div(self.to_dense(f), self.to_dense(g), self.domain)
return (self.from_dense(q), self.from_dense(r))
def dmp_ff_div(self, f, g):
q, r = dmp_ff_div(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain)
return (self.from_dense(q), self.from_dense(r))
def dup_div(self, f, g):
q, r = dup_div(self.to_dense(f), self.to_dense(g), self.domain)
return (self.from_dense(q), self.from_dense(r))
def dup_rem(self, f, g):
return self.from_dense(dup_rem(self.to_dense(f), self.to_dense(g), self.domain))
def dup_quo(self, f, g):
return self.from_dense(dup_quo(self.to_dense(f), self.to_dense(g), self.domain))
def dup_exquo(self, f, g):
return self.from_dense(dup_exquo(self.to_dense(f), self.to_dense(g), self.domain))
def dmp_div(self, f, g):
q, r = dmp_div(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain)
return (self.from_dense(q), self.from_dense(r))
def dmp_rem(self, f, g):
return self.from_dense(dmp_rem(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain))
def dmp_quo(self, f, g):
return self.from_dense(dmp_quo(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain))
def dmp_exquo(self, f, g):
return self.from_dense(dmp_exquo(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain))
def dup_max_norm(self, f):
return dup_max_norm(self.to_dense(f), self.domain)
def dmp_max_norm(self, f):
return dmp_max_norm(self.to_dense(f), self.ngens-1, self.domain)
def dup_l1_norm(self, f):
return dup_l1_norm(self.to_dense(f), self.domain)
def dmp_l1_norm(self, f):
return dmp_l1_norm(self.to_dense(f), self.ngens-1, self.domain)
def dup_l2_norm_squared(self, f):
return dup_l2_norm_squared(self.to_dense(f), self.domain)
def dmp_l2_norm_squared(self, f):
return dmp_l2_norm_squared(self.to_dense(f), self.ngens-1, self.domain)
def dup_expand(self, polys):
return self.from_dense(dup_expand(list(map(self.to_dense, polys)), self.domain))
def dmp_expand(self, polys):
return self.from_dense(dmp_expand(list(map(self.to_dense, polys)), self.ngens-1, self.domain))
def dup_LC(self, f):
return dup_LC(self.to_dense(f), self.domain)
def dmp_LC(self, f):
LC = dmp_LC(self.to_dense(f), self.domain)
if isinstance(LC, list):
return self[1:].from_dense(LC)
else:
return LC
def dup_TC(self, f):
return dup_TC(self.to_dense(f), self.domain)
def dmp_TC(self, f):
TC = dmp_TC(self.to_dense(f), self.domain)
if isinstance(TC, list):
return self[1:].from_dense(TC)
else:
return TC
def dmp_ground_LC(self, f):
return dmp_ground_LC(self.to_dense(f), self.ngens-1, self.domain)
def dmp_ground_TC(self, f):
return dmp_ground_TC(self.to_dense(f), self.ngens-1, self.domain)
def dup_degree(self, f):
return dup_degree(self.to_dense(f))
def dmp_degree(self, f):
return dmp_degree(self.to_dense(f), self.ngens-1)
def dmp_degree_in(self, f, j):
return dmp_degree_in(self.to_dense(f), j, self.ngens-1)
def dup_integrate(self, f, m):
return self.from_dense(dup_integrate(self.to_dense(f), m, self.domain))
def dmp_integrate(self, f, m):
return self.from_dense(dmp_integrate(self.to_dense(f), m, self.ngens-1, self.domain))
def dup_diff(self, f, m):
return self.from_dense(dup_diff(self.to_dense(f), m, self.domain))
def dmp_diff(self, f, m):
return self.from_dense(dmp_diff(self.to_dense(f), m, self.ngens-1, self.domain))
def dmp_diff_in(self, f, m, j):
return self.from_dense(dmp_diff_in(self.to_dense(f), m, j, self.ngens-1, self.domain))
def dmp_integrate_in(self, f, m, j):
return self.from_dense(dmp_integrate_in(self.to_dense(f), m, j, self.ngens-1, self.domain))
def dup_eval(self, f, a):
return dup_eval(self.to_dense(f), a, self.domain)
def dmp_eval(self, f, a):
result = dmp_eval(self.to_dense(f), a, self.ngens-1, self.domain)
return self[1:].from_dense(result)
def dmp_eval_in(self, f, a, j):
result = dmp_eval_in(self.to_dense(f), a, j, self.ngens-1, self.domain)
return self.drop(j).from_dense(result)
def dmp_diff_eval_in(self, f, m, a, j):
result = dmp_diff_eval_in(self.to_dense(f), m, a, j, self.ngens-1, self.domain)
return self.drop(j).from_dense(result)
def dmp_eval_tail(self, f, A):
result = dmp_eval_tail(self.to_dense(f), A, self.ngens-1, self.domain)
if isinstance(result, list):
return self[:-len(A)].from_dense(result)
else:
return result
def dup_trunc(self, f, p):
return self.from_dense(dup_trunc(self.to_dense(f), p, self.domain))
def dmp_trunc(self, f, g):
return self.from_dense(dmp_trunc(self.to_dense(f), self[1:].to_dense(g), self.ngens-1, self.domain))
def dmp_ground_trunc(self, f, p):
return self.from_dense(dmp_ground_trunc(self.to_dense(f), p, self.ngens-1, self.domain))
def dup_monic(self, f):
return self.from_dense(dup_monic(self.to_dense(f), self.domain))
def dmp_ground_monic(self, f):
return self.from_dense(dmp_ground_monic(self.to_dense(f), self.ngens-1, self.domain))
def dup_extract(self, f, g):
c, F, G = dup_extract(self.to_dense(f), self.to_dense(g), self.domain)
return (c, self.from_dense(F), self.from_dense(G))
def dmp_ground_extract(self, f, g):
c, F, G = dmp_ground_extract(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain)
return (c, self.from_dense(F), self.from_dense(G))
def dup_real_imag(self, f):
p, q = dup_real_imag(self.wrap(f).drop(1).to_dense(), self.domain)
return (self.from_dense(p), self.from_dense(q))
def dup_mirror(self, f):
return self.from_dense(dup_mirror(self.to_dense(f), self.domain))
def dup_scale(self, f, a):
return self.from_dense(dup_scale(self.to_dense(f), a, self.domain))
def dup_shift(self, f, a):
return self.from_dense(dup_shift(self.to_dense(f), a, self.domain))
def dmp_shift(self, f, a):
return self.from_dense(dmp_shift(self.to_dense(f), a, self.ngens-1, self.domain))
def dup_transform(self, f, p, q):
return self.from_dense(dup_transform(self.to_dense(f), self.to_dense(p), self.to_dense(q), self.domain))
def dup_compose(self, f, g):
return self.from_dense(dup_compose(self.to_dense(f), self.to_dense(g), self.domain))
def dmp_compose(self, f, g):
return self.from_dense(dmp_compose(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain))
def dup_decompose(self, f):
components = dup_decompose(self.to_dense(f), self.domain)
return list(map(self.from_dense, components))
def dmp_lift(self, f):
result = dmp_lift(self.to_dense(f), self.ngens-1, self.domain)
return self.to_ground().from_dense(result)
def dup_sign_variations(self, f):
return dup_sign_variations(self.to_dense(f), self.domain)
def dup_clear_denoms(self, f, convert=False):
c, F = dup_clear_denoms(self.to_dense(f), self.domain, convert=convert)
if convert:
ring = self.clone(domain=self.domain.get_ring())
else:
ring = self
return (c, ring.from_dense(F))
def dmp_clear_denoms(self, f, convert=False):
c, F = dmp_clear_denoms(self.to_dense(f), self.ngens-1, self.domain, convert=convert)
if convert:
ring = self.clone(domain=self.domain.get_ring())
else:
ring = self
return (c, ring.from_dense(F))
def dup_revert(self, f, n):
return self.from_dense(dup_revert(self.to_dense(f), n, self.domain))
def dup_half_gcdex(self, f, g):
s, h = dup_half_gcdex(self.to_dense(f), self.to_dense(g), self.domain)
return (self.from_dense(s), self.from_dense(h))
def dmp_half_gcdex(self, f, g):
s, h = dmp_half_gcdex(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain)
return (self.from_dense(s), self.from_dense(h))
def dup_gcdex(self, f, g):
s, t, h = dup_gcdex(self.to_dense(f), self.to_dense(g), self.domain)
return (self.from_dense(s), self.from_dense(t), self.from_dense(h))
def dmp_gcdex(self, f, g):
s, t, h = dmp_gcdex(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain)
return (self.from_dense(s), self.from_dense(t), self.from_dense(h))
def dup_invert(self, f, g):
return self.from_dense(dup_invert(self.to_dense(f), self.to_dense(g), self.domain))
def dmp_invert(self, f, g):
return self.from_dense(dmp_invert(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain))
def dup_euclidean_prs(self, f, g):
prs = dup_euclidean_prs(self.to_dense(f), self.to_dense(g), self.domain)
return list(map(self.from_dense, prs))
def dmp_euclidean_prs(self, f, g):
prs = dmp_euclidean_prs(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain)
return list(map(self.from_dense, prs))
def dup_primitive_prs(self, f, g):
prs = dup_primitive_prs(self.to_dense(f), self.to_dense(g), self.domain)
return list(map(self.from_dense, prs))
def dmp_primitive_prs(self, f, g):
prs = dmp_primitive_prs(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain)
return list(map(self.from_dense, prs))
def dup_inner_subresultants(self, f, g):
prs, sres = dup_inner_subresultants(self.to_dense(f), self.to_dense(g), self.domain)
return (list(map(self.from_dense, prs)), sres)
def dmp_inner_subresultants(self, f, g):
prs, sres = dmp_inner_subresultants(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain)
return (list(map(self.from_dense, prs)), sres)
def dup_subresultants(self, f, g):
prs = dup_subresultants(self.to_dense(f), self.to_dense(g), self.domain)
return list(map(self.from_dense, prs))
def dmp_subresultants(self, f, g):
prs = dmp_subresultants(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain)
return list(map(self.from_dense, prs))
def dup_prs_resultant(self, f, g):
res, prs = dup_prs_resultant(self.to_dense(f), self.to_dense(g), self.domain)
return (res, list(map(self.from_dense, prs)))
def dmp_prs_resultant(self, f, g):
res, prs = dmp_prs_resultant(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain)
return (self[1:].from_dense(res), list(map(self.from_dense, prs)))
def dmp_zz_modular_resultant(self, f, g, p):
res = dmp_zz_modular_resultant(self.to_dense(f), self.to_dense(g), self.domain_new(p), self.ngens-1, self.domain)
return self[1:].from_dense(res)
def dmp_zz_collins_resultant(self, f, g):
res = dmp_zz_collins_resultant(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain)
return self[1:].from_dense(res)
def dmp_qq_collins_resultant(self, f, g):
res = dmp_qq_collins_resultant(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain)
return self[1:].from_dense(res)
def dup_resultant(self, f, g): #, includePRS=False):
return dup_resultant(self.to_dense(f), self.to_dense(g), self.domain) #, includePRS=includePRS)
def dmp_resultant(self, f, g): #, includePRS=False):
res = dmp_resultant(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain) #, includePRS=includePRS)
if isinstance(res, list):
return self[1:].from_dense(res)
else:
return res
def dup_discriminant(self, f):
return dup_discriminant(self.to_dense(f), self.domain)
def dmp_discriminant(self, f):
disc = dmp_discriminant(self.to_dense(f), self.ngens-1, self.domain)
if isinstance(disc, list):
return self[1:].from_dense(disc)
else:
return disc
def dup_rr_prs_gcd(self, f, g):
H, F, G = dup_rr_prs_gcd(self.to_dense(f), self.to_dense(g), self.domain)
return (self.from_dense(H), self.from_dense(F), self.from_dense(G))
def dup_ff_prs_gcd(self, f, g):
H, F, G = dup_ff_prs_gcd(self.to_dense(f), self.to_dense(g), self.domain)
return (self.from_dense(H), self.from_dense(F), self.from_dense(G))
def dmp_rr_prs_gcd(self, f, g):
H, F, G = dmp_rr_prs_gcd(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain)
return (self.from_dense(H), self.from_dense(F), self.from_dense(G))
def dmp_ff_prs_gcd(self, f, g):
H, F, G = dmp_ff_prs_gcd(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain)
return (self.from_dense(H), self.from_dense(F), self.from_dense(G))
def dup_zz_heu_gcd(self, f, g):
H, F, G = dup_zz_heu_gcd(self.to_dense(f), self.to_dense(g), self.domain)
return (self.from_dense(H), self.from_dense(F), self.from_dense(G))
def dmp_zz_heu_gcd(self, f, g):
H, F, G = dmp_zz_heu_gcd(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain)
return (self.from_dense(H), self.from_dense(F), self.from_dense(G))
def dup_qq_heu_gcd(self, f, g):
H, F, G = dup_qq_heu_gcd(self.to_dense(f), self.to_dense(g), self.domain)
return (self.from_dense(H), self.from_dense(F), self.from_dense(G))
def dmp_qq_heu_gcd(self, f, g):
H, F, G = dmp_qq_heu_gcd(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain)
return (self.from_dense(H), self.from_dense(F), self.from_dense(G))
def dup_inner_gcd(self, f, g):
H, F, G = dup_inner_gcd(self.to_dense(f), self.to_dense(g), self.domain)
return (self.from_dense(H), self.from_dense(F), self.from_dense(G))
def dmp_inner_gcd(self, f, g):
H, F, G = dmp_inner_gcd(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain)
return (self.from_dense(H), self.from_dense(F), self.from_dense(G))
def dup_gcd(self, f, g):
H = dup_gcd(self.to_dense(f), self.to_dense(g), self.domain)
return self.from_dense(H)
def dmp_gcd(self, f, g):
H = dmp_gcd(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain)
return self.from_dense(H)
def dup_rr_lcm(self, f, g):
H = dup_rr_lcm(self.to_dense(f), self.to_dense(g), self.domain)
return self.from_dense(H)
def dup_ff_lcm(self, f, g):
H = dup_ff_lcm(self.to_dense(f), self.to_dense(g), self.domain)
return self.from_dense(H)
def dup_lcm(self, f, g):
H = dup_lcm(self.to_dense(f), self.to_dense(g), self.domain)
return self.from_dense(H)
def dmp_rr_lcm(self, f, g):
H = dmp_rr_lcm(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain)
return self.from_dense(H)
def dmp_ff_lcm(self, f, g):
H = dmp_ff_lcm(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain)
return self.from_dense(H)
def dmp_lcm(self, f, g):
H = dmp_lcm(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain)
return self.from_dense(H)
def dup_content(self, f):
cont = dup_content(self.to_dense(f), self.domain)
return cont
def dup_primitive(self, f):
cont, prim = dup_primitive(self.to_dense(f), self.domain)
return cont, self.from_dense(prim)
def dmp_content(self, f):
cont = dmp_content(self.to_dense(f), self.ngens-1, self.domain)
if isinstance(cont, list):
return self[1:].from_dense(cont)
else:
return cont
def dmp_primitive(self, f):
cont, prim = dmp_primitive(self.to_dense(f), self.ngens-1, self.domain)
if isinstance(cont, list):
return (self[1:].from_dense(cont), self.from_dense(prim))
else:
return (cont, self.from_dense(prim))
def dmp_ground_content(self, f):
cont = dmp_ground_content(self.to_dense(f), self.ngens-1, self.domain)
return cont
def dmp_ground_primitive(self, f):
cont, prim = dmp_ground_primitive(self.to_dense(f), self.ngens-1, self.domain)
return (cont, self.from_dense(prim))
def dup_cancel(self, f, g, include=True):
result = dup_cancel(self.to_dense(f), self.to_dense(g), self.domain, include=include)
if not include:
cf, cg, F, G = result
return (cf, cg, self.from_dense(F), self.from_dense(G))
else:
F, G = result
return (self.from_dense(F), self.from_dense(G))
def dmp_cancel(self, f, g, include=True):
result = dmp_cancel(self.to_dense(f), self.to_dense(g), self.ngens-1, self.domain, include=include)
if not include:
cf, cg, F, G = result
return (cf, cg, self.from_dense(F), self.from_dense(G))
else:
F, G = result
return (self.from_dense(F), self.from_dense(G))
def dup_trial_division(self, f, factors):
factors = dup_trial_division(self.to_dense(f), list(map(self.to_dense, factors)), self.domain)
return [ (self.from_dense(g), k) for g, k in factors ]
def dmp_trial_division(self, f, factors):
factors = dmp_trial_division(self.to_dense(f), list(map(self.to_dense, factors)), self.ngens-1, self.domain)
return [ (self.from_dense(g), k) for g, k in factors ]
def dup_zz_mignotte_bound(self, f):
return dup_zz_mignotte_bound(self.to_dense(f), self.domain)
def dmp_zz_mignotte_bound(self, f):
return dmp_zz_mignotte_bound(self.to_dense(f), self.ngens-1, self.domain)
def dup_zz_hensel_step(self, m, f, g, h, s, t):
D = self.to_dense
G, H, S, T = dup_zz_hensel_step(m, D(f), D(g), D(h), D(s), D(t), self.domain)
return (self.from_dense(G), self.from_dense(H), self.from_dense(S), self.from_dense(T))
def dup_zz_hensel_lift(self, p, f, f_list, l):
D = self.to_dense
polys = dup_zz_hensel_lift(p, D(f), list(map(D, f_list)), l, self.domain)
return list(map(self.from_dense, polys))
def dup_zz_zassenhaus(self, f):
factors = dup_zz_zassenhaus(self.to_dense(f), self.domain)
return [ (self.from_dense(g), k) for g, k in factors ]
def dup_zz_irreducible_p(self, f):
return dup_zz_irreducible_p(self.to_dense(f), self.domain)
def dup_cyclotomic_p(self, f, irreducible=False):
return dup_cyclotomic_p(self.to_dense(f), self.domain, irreducible=irreducible)
def dup_zz_cyclotomic_poly(self, n):
F = dup_zz_cyclotomic_poly(n, self.domain)
return self.from_dense(F)
def dup_zz_cyclotomic_factor(self, f):
result = dup_zz_cyclotomic_factor(self.to_dense(f), self.domain)
if result is None:
return result
else:
return list(map(self.from_dense, result))
# E: List[ZZ], cs: ZZ, ct: ZZ
def dmp_zz_wang_non_divisors(self, E, cs, ct):
return dmp_zz_wang_non_divisors(E, cs, ct, self.domain)
# f: Poly, T: List[(Poly, int)], ct: ZZ, A: List[ZZ]
#def dmp_zz_wang_test_points(f, T, ct, A):
# dmp_zz_wang_test_points(self.to_dense(f), T, ct, A, self.ngens-1, self.domain)
# f: Poly, T: List[(Poly, int)], cs: ZZ, E: List[ZZ], H: List[Poly], A: List[ZZ]
def dmp_zz_wang_lead_coeffs(self, f, T, cs, E, H, A):
mv = self[1:]
T = [ (mv.to_dense(t), k) for t, k in T ]
uv = self[:1]
H = list(map(uv.to_dense, H))
f, HH, CC = dmp_zz_wang_lead_coeffs(self.to_dense(f), T, cs, E, H, A, self.ngens-1, self.domain)
return self.from_dense(f), list(map(uv.from_dense, HH)), list(map(mv.from_dense, CC))
# f: List[Poly], m: int, p: ZZ
def dup_zz_diophantine(self, F, m, p):
result = dup_zz_diophantine(list(map(self.to_dense, F)), m, p, self.domain)
return list(map(self.from_dense, result))
# f: List[Poly], c: List[Poly], A: List[ZZ], d: int, p: ZZ
def dmp_zz_diophantine(self, F, c, A, d, p):
result = dmp_zz_diophantine(list(map(self.to_dense, F)), self.to_dense(c), A, d, p, self.ngens-1, self.domain)
return list(map(self.from_dense, result))
# f: Poly, H: List[Poly], LC: List[Poly], A: List[ZZ], p: ZZ
def dmp_zz_wang_hensel_lifting(self, f, H, LC, A, p):
uv = self[:1]
mv = self[1:]
H = list(map(uv.to_dense, H))
LC = list(map(mv.to_dense, LC))
result = dmp_zz_wang_hensel_lifting(self.to_dense(f), H, LC, A, p, self.ngens-1, self.domain)
return list(map(self.from_dense, result))
def dmp_zz_wang(self, f, mod=None, seed=None):
factors = dmp_zz_wang(self.to_dense(f), self.ngens-1, self.domain, mod=mod, seed=seed)
return [ self.from_dense(g) for g in factors ]
def dup_zz_factor_sqf(self, f):
coeff, factors = dup_zz_factor_sqf(self.to_dense(f), self.domain)
return (coeff, [ self.from_dense(g) for g in factors ])
def dup_zz_factor(self, f):
coeff, factors = dup_zz_factor(self.to_dense(f), self.domain)
return (coeff, [ (self.from_dense(g), k) for g, k in factors ])
def dmp_zz_factor(self, f):
coeff, factors = dmp_zz_factor(self.to_dense(f), self.ngens-1, self.domain)
return (coeff, [ (self.from_dense(g), k) for g, k in factors ])
def dup_qq_i_factor(self, f):
coeff, factors = dup_qq_i_factor(self.to_dense(f), self.domain)
return (coeff, [ (self.from_dense(g), k) for g, k in factors ])
def dmp_qq_i_factor(self, f):
coeff, factors = dmp_qq_i_factor(self.to_dense(f), self.ngens-1, self.domain)
return (coeff, [ (self.from_dense(g), k) for g, k in factors ])
def dup_zz_i_factor(self, f):
coeff, factors = dup_zz_i_factor(self.to_dense(f), self.domain)
return (coeff, [ (self.from_dense(g), k) for g, k in factors ])
def dmp_zz_i_factor(self, f):
coeff, factors = dmp_zz_i_factor(self.to_dense(f), self.ngens-1, self.domain)
return (coeff, [ (self.from_dense(g), k) for g, k in factors ])
def dup_ext_factor(self, f):
coeff, factors = dup_ext_factor(self.to_dense(f), self.domain)
return (coeff, [ (self.from_dense(g), k) for g, k in factors ])
def dmp_ext_factor(self, f):
coeff, factors = dmp_ext_factor(self.to_dense(f), self.ngens-1, self.domain)
return (coeff, [ (self.from_dense(g), k) for g, k in factors ])
def dup_gf_factor(self, f):
coeff, factors = dup_gf_factor(self.to_dense(f), self.domain)
return (coeff, [ (self.from_dense(g), k) for g, k in factors ])
def dmp_gf_factor(self, f):
coeff, factors = dmp_gf_factor(self.to_dense(f), self.ngens-1, self.domain)
return (coeff, [ (self.from_dense(g), k) for g, k in factors ])
def dup_factor_list(self, f):
coeff, factors = dup_factor_list(self.to_dense(f), self.domain)
return (coeff, [ (self.from_dense(g), k) for g, k in factors ])
def dup_factor_list_include(self, f):
factors = dup_factor_list_include(self.to_dense(f), self.domain)
return [ (self.from_dense(g), k) for g, k in factors ]
def dmp_factor_list(self, f):
coeff, factors = dmp_factor_list(self.to_dense(f), self.ngens-1, self.domain)
return (coeff, [ (self.from_dense(g), k) for g, k in factors ])
def dmp_factor_list_include(self, f):
factors = dmp_factor_list_include(self.to_dense(f), self.ngens-1, self.domain)
return [ (self.from_dense(g), k) for g, k in factors ]
def dup_irreducible_p(self, f):
return dup_irreducible_p(self.to_dense(f), self.domain)
def dmp_irreducible_p(self, f):
return dmp_irreducible_p(self.to_dense(f), self.ngens-1, self.domain)
def dup_sturm(self, f):
seq = dup_sturm(self.to_dense(f), self.domain)
return list(map(self.from_dense, seq))
def dup_sqf_p(self, f):
return dup_sqf_p(self.to_dense(f), self.domain)
def dmp_sqf_p(self, f):
return dmp_sqf_p(self.to_dense(f), self.ngens-1, self.domain)
def dmp_norm(self, f):
n = dmp_norm(self.to_dense(f), self.ngens-1, self.domain)
return self.to_ground().from_dense(n)
def dup_sqf_norm(self, f):
s, F, R = dup_sqf_norm(self.to_dense(f), self.domain)
return (s, self.from_dense(F), self.to_ground().from_dense(R))
def dmp_sqf_norm(self, f):
s, F, R = dmp_sqf_norm(self.to_dense(f), self.ngens-1, self.domain)
return (s, self.from_dense(F), self.to_ground().from_dense(R))
def dup_gf_sqf_part(self, f):
return self.from_dense(dup_gf_sqf_part(self.to_dense(f), self.domain))
def dmp_gf_sqf_part(self, f):
return self.from_dense(dmp_gf_sqf_part(self.to_dense(f), self.domain))
def dup_sqf_part(self, f):
return self.from_dense(dup_sqf_part(self.to_dense(f), self.domain))
def dmp_sqf_part(self, f):
return self.from_dense(dmp_sqf_part(self.to_dense(f), self.ngens-1, self.domain))
def dup_gf_sqf_list(self, f, all=False):
coeff, factors = dup_gf_sqf_list(self.to_dense(f), self.domain, all=all)
return (coeff, [ (self.from_dense(g), k) for g, k in factors ])
def dmp_gf_sqf_list(self, f, all=False):
coeff, factors = dmp_gf_sqf_list(self.to_dense(f), self.ngens-1, self.domain, all=all)
return (coeff, [ (self.from_dense(g), k) for g, k in factors ])
def dup_sqf_list(self, f, all=False):
coeff, factors = dup_sqf_list(self.to_dense(f), self.domain, all=all)
return (coeff, [ (self.from_dense(g), k) for g, k in factors ])
def dup_sqf_list_include(self, f, all=False):
factors = dup_sqf_list_include(self.to_dense(f), self.domain, all=all)
return [ (self.from_dense(g), k) for g, k in factors ]
def dmp_sqf_list(self, f, all=False):
coeff, factors = dmp_sqf_list(self.to_dense(f), self.ngens-1, self.domain, all=all)
return (coeff, [ (self.from_dense(g), k) for g, k in factors ])
def dmp_sqf_list_include(self, f, all=False):
factors = dmp_sqf_list_include(self.to_dense(f), self.ngens-1, self.domain, all=all)
return [ (self.from_dense(g), k) for g, k in factors ]
def dup_gff_list(self, f):
factors = dup_gff_list(self.to_dense(f), self.domain)
return [ (self.from_dense(g), k) for g, k in factors ]
def dmp_gff_list(self, f):
factors = dmp_gff_list(self.to_dense(f), self.ngens-1, self.domain)
return [ (self.from_dense(g), k) for g, k in factors ]
def dup_root_upper_bound(self, f):
return dup_root_upper_bound(self.to_dense(f), self.domain)
def dup_root_lower_bound(self, f):
return dup_root_lower_bound(self.to_dense(f), self.domain)
def dup_step_refine_real_root(self, f, M, fast=False):
return dup_step_refine_real_root(self.to_dense(f), M, self.domain, fast=fast)
def dup_inner_refine_real_root(self, f, M, eps=None, steps=None, disjoint=None, fast=False, mobius=False):
return dup_inner_refine_real_root(self.to_dense(f), M, self.domain, eps=eps, steps=steps, disjoint=disjoint, fast=fast, mobius=mobius)
def dup_outer_refine_real_root(self, f, s, t, eps=None, steps=None, disjoint=None, fast=False):
return dup_outer_refine_real_root(self.to_dense(f), s, t, self.domain, eps=eps, steps=steps, disjoint=disjoint, fast=fast)
def dup_refine_real_root(self, f, s, t, eps=None, steps=None, disjoint=None, fast=False):
return dup_refine_real_root(self.to_dense(f), s, t, self.domain, eps=eps, steps=steps, disjoint=disjoint, fast=fast)
def dup_inner_isolate_real_roots(self, f, eps=None, fast=False):
return dup_inner_isolate_real_roots(self.to_dense(f), self.domain, eps=eps, fast=fast)
def dup_inner_isolate_positive_roots(self, f, eps=None, inf=None, sup=None, fast=False, mobius=False):
return dup_inner_isolate_positive_roots(self.to_dense(f), self.domain, eps=eps, inf=inf, sup=sup, fast=fast, mobius=mobius)
def dup_inner_isolate_negative_roots(self, f, inf=None, sup=None, eps=None, fast=False, mobius=False):
return dup_inner_isolate_negative_roots(self.to_dense(f), self.domain, inf=inf, sup=sup, eps=eps, fast=fast, mobius=mobius)
def dup_isolate_real_roots_sqf(self, f, eps=None, inf=None, sup=None, fast=False, blackbox=False):
return dup_isolate_real_roots_sqf(self.to_dense(f), self.domain, eps=eps, inf=inf, sup=sup, fast=fast, blackbox=blackbox)
def dup_isolate_real_roots(self, f, eps=None, inf=None, sup=None, basis=False, fast=False):
return dup_isolate_real_roots(self.to_dense(f), self.domain, eps=eps, inf=inf, sup=sup, basis=basis, fast=fast)
def dup_isolate_real_roots_list(self, polys, eps=None, inf=None, sup=None, strict=False, basis=False, fast=False):
return dup_isolate_real_roots_list(list(map(self.to_dense, polys)), self.domain, eps=eps, inf=inf, sup=sup, strict=strict, basis=basis, fast=fast)
def dup_count_real_roots(self, f, inf=None, sup=None):
return dup_count_real_roots(self.to_dense(f), self.domain, inf=inf, sup=sup)
def dup_count_complex_roots(self, f, inf=None, sup=None, exclude=None):
return dup_count_complex_roots(self.to_dense(f), self.domain, inf=inf, sup=sup, exclude=exclude)
def dup_isolate_complex_roots_sqf(self, f, eps=None, inf=None, sup=None, blackbox=False):
return dup_isolate_complex_roots_sqf(self.to_dense(f), self.domain, eps=eps, inf=inf, sup=sup, blackbox=blackbox)
def dup_isolate_all_roots_sqf(self, f, eps=None, inf=None, sup=None, fast=False, blackbox=False):
return dup_isolate_all_roots_sqf(self.to_dense(f), self.domain, eps=eps, inf=inf, sup=sup, fast=fast, blackbox=blackbox)
def dup_isolate_all_roots(self, f, eps=None, inf=None, sup=None, fast=False):
return dup_isolate_all_roots(self.to_dense(f), self.domain, eps=eps, inf=inf, sup=sup, fast=fast)
def fateman_poly_F_1(self):
from sympy.polys.specialpolys import dmp_fateman_poly_F_1
return tuple(map(self.from_dense, dmp_fateman_poly_F_1(self.ngens-1, self.domain)))
def fateman_poly_F_2(self):
from sympy.polys.specialpolys import dmp_fateman_poly_F_2
return tuple(map(self.from_dense, dmp_fateman_poly_F_2(self.ngens-1, self.domain)))
def fateman_poly_F_3(self):
from sympy.polys.specialpolys import dmp_fateman_poly_F_3
return tuple(map(self.from_dense, dmp_fateman_poly_F_3(self.ngens-1, self.domain)))
def to_gf_dense(self, element):
return gf_strip([ self.domain.dom.convert(c, self.domain) for c in self.wrap(element).to_dense() ])
def from_gf_dense(self, element):
return self.from_dict(dmp_to_dict(element, self.ngens-1, self.domain.dom))
def gf_degree(self, f):
return gf_degree(self.to_gf_dense(f))
def gf_LC(self, f):
return gf_LC(self.to_gf_dense(f), self.domain.dom)
def gf_TC(self, f):
return gf_TC(self.to_gf_dense(f), self.domain.dom)
def gf_strip(self, f):
return self.from_gf_dense(gf_strip(self.to_gf_dense(f)))
def gf_trunc(self, f):
return self.from_gf_dense(gf_strip(self.to_gf_dense(f), self.domain.mod))
def gf_normal(self, f):
return self.from_gf_dense(gf_strip(self.to_gf_dense(f), self.domain.mod, self.domain.dom))
def gf_from_dict(self, f):
return self.from_gf_dense(gf_from_dict(f, self.domain.mod, self.domain.dom))
def gf_to_dict(self, f, symmetric=True):
return gf_to_dict(self.to_gf_dense(f), self.domain.mod, symmetric=symmetric)
def gf_from_int_poly(self, f):
return self.from_gf_dense(gf_from_int_poly(f, self.domain.mod))
def gf_to_int_poly(self, f, symmetric=True):
return gf_to_int_poly(self.to_gf_dense(f), self.domain.mod, symmetric=symmetric)
def gf_neg(self, f):
return self.from_gf_dense(gf_neg(self.to_gf_dense(f), self.domain.mod, self.domain.dom))
def gf_add_ground(self, f, a):
return self.from_gf_dense(gf_add_ground(self.to_gf_dense(f), a, self.domain.mod, self.domain.dom))
def gf_sub_ground(self, f, a):
return self.from_gf_dense(gf_sub_ground(self.to_gf_dense(f), a, self.domain.mod, self.domain.dom))
def gf_mul_ground(self, f, a):
return self.from_gf_dense(gf_mul_ground(self.to_gf_dense(f), a, self.domain.mod, self.domain.dom))
def gf_quo_ground(self, f, a):
return self.from_gf_dense(gf_quo_ground(self.to_gf_dense(f), a, self.domain.mod, self.domain.dom))
def gf_add(self, f, g):
return self.from_gf_dense(gf_add(self.to_gf_dense(f), self.to_gf_dense(g), self.domain.mod, self.domain.dom))
def gf_sub(self, f, g):
return self.from_gf_dense(gf_sub(self.to_gf_dense(f), self.to_gf_dense(g), self.domain.mod, self.domain.dom))
def gf_mul(self, f, g):
return self.from_gf_dense(gf_mul(self.to_gf_dense(f), self.to_gf_dense(g), self.domain.mod, self.domain.dom))
def gf_sqr(self, f):
return self.from_gf_dense(gf_sqr(self.to_gf_dense(f), self.domain.mod, self.domain.dom))
def gf_add_mul(self, f, g, h):
return self.from_gf_dense(gf_add_mul(self.to_gf_dense(f), self.to_gf_dense(g), self.to_gf_dense(h), self.domain.mod, self.domain.dom))
def gf_sub_mul(self, f, g, h):
return self.from_gf_dense(gf_sub_mul(self.to_gf_dense(f), self.to_gf_dense(g), self.to_gf_dense(h), self.domain.mod, self.domain.dom))
def gf_expand(self, F):
return self.from_gf_dense(gf_expand(list(map(self.to_gf_dense, F)), self.domain.mod, self.domain.dom))
def gf_div(self, f, g):
q, r = gf_div(self.to_gf_dense(f), self.to_gf_dense(g), self.domain.mod, self.domain.dom)
return self.from_gf_dense(q), self.from_gf_dense(r)
def gf_rem(self, f, g):
return self.from_gf_dense(gf_rem(self.to_gf_dense(f), self.to_gf_dense(g), self.domain.mod, self.domain.dom))
def gf_quo(self, f, g):
return self.from_gf_dense(gf_quo(self.to_gf_dense(f), self.to_gf_dense(g), self.domain.mod, self.domain.dom))
def gf_exquo(self, f, g):
return self.from_gf_dense(gf_exquo(self.to_gf_dense(f), self.to_gf_dense(g), self.domain.mod, self.domain.dom))
def gf_lshift(self, f, n):
return self.from_gf_dense(gf_lshift(self.to_gf_dense(f), n, self.domain.dom))
def gf_rshift(self, f, n):
return self.from_gf_dense(gf_rshift(self.to_gf_dense(f), n, self.domain.dom))
def gf_pow(self, f, n):
return self.from_gf_dense(gf_pow(self.to_gf_dense(f), n, self.domain.mod, self.domain.dom))
def gf_pow_mod(self, f, n, g):
return self.from_gf_dense(gf_pow_mod(self.to_gf_dense(f), n, self.to_gf_dense(g), self.domain.mod, self.domain.dom))
def gf_cofactors(self, f, g):
h, cff, cfg = gf_cofactors(self.to_gf_dense(f), self.to_gf_dense(g), self.domain.mod, self.domain.dom)
return self.from_gf_dense(h), self.from_gf_dense(cff), self.from_gf_dense(cfg)
def gf_gcd(self, f, g):
return self.from_gf_dense(gf_gcd(self.to_gf_dense(f), self.to_gf_dense(g), self.domain.mod, self.domain.dom))
def gf_lcm(self, f, g):
return self.from_gf_dense(gf_lcm(self.to_gf_dense(f), self.to_gf_dense(g), self.domain.mod, self.domain.dom))
def gf_gcdex(self, f, g):
return self.from_gf_dense(gf_gcdex(self.to_gf_dense(f), self.to_gf_dense(g), self.domain.mod, self.domain.dom))
def gf_monic(self, f):
return self.from_gf_dense(gf_monic(self.to_gf_dense(f), self.domain.mod, self.domain.dom))
def gf_diff(self, f):
return self.from_gf_dense(gf_diff(self.to_gf_dense(f), self.domain.mod, self.domain.dom))
def gf_eval(self, f, a):
return gf_eval(self.to_gf_dense(f), a, self.domain.mod, self.domain.dom)
def gf_multi_eval(self, f, A):
return gf_multi_eval(self.to_gf_dense(f), A, self.domain.mod, self.domain.dom)
def gf_compose(self, f, g):
return self.from_gf_dense(gf_compose(self.to_gf_dense(f), self.to_gf_dense(g), self.domain.mod, self.domain.dom))
def gf_compose_mod(self, g, h, f):
return self.from_gf_dense(gf_compose_mod(self.to_gf_dense(g), self.to_gf_dense(h), self.to_gf_dense(f), self.domain.mod, self.domain.dom))
def gf_trace_map(self, a, b, c, n, f):
a = self.to_gf_dense(a)
b = self.to_gf_dense(b)
c = self.to_gf_dense(c)
f = self.to_gf_dense(f)
U, V = gf_trace_map(a, b, c, n, f, self.domain.mod, self.domain.dom)
return self.from_gf_dense(U), self.from_gf_dense(V)
def gf_random(self, n):
return self.from_gf_dense(gf_random(n, self.domain.mod, self.domain.dom))
def gf_irreducible(self, n):
return self.from_gf_dense(gf_irreducible(n, self.domain.mod, self.domain.dom))
def gf_irred_p_ben_or(self, f):
return gf_irred_p_ben_or(self.to_gf_dense(f), self.domain.mod, self.domain.dom)
def gf_irred_p_rabin(self, f):
return gf_irred_p_rabin(self.to_gf_dense(f), self.domain.mod, self.domain.dom)
def gf_irreducible_p(self, f):
return gf_irreducible_p(self.to_gf_dense(f), self.domain.mod, self.domain.dom)
def gf_sqf_p(self, f):
return gf_sqf_p(self.to_gf_dense(f), self.domain.mod, self.domain.dom)
def gf_sqf_part(self, f):
return self.from_gf_dense(gf_sqf_part(self.to_gf_dense(f), self.domain.mod, self.domain.dom))
def gf_sqf_list(self, f, all=False):
coeff, factors = gf_sqf_part(self.to_gf_dense(f), self.domain.mod, self.domain.dom)
return coeff, [ (self.from_gf_dense(g), k) for g, k in factors ]
def gf_Qmatrix(self, f):
return gf_Qmatrix(self.to_gf_dense(f), self.domain.mod, self.domain.dom)
def gf_berlekamp(self, f):
factors = gf_berlekamp(self.to_gf_dense(f), self.domain.mod, self.domain.dom)
return [ self.from_gf_dense(g) for g in factors ]
def gf_ddf_zassenhaus(self, f):
factors = gf_ddf_zassenhaus(self.to_gf_dense(f), self.domain.mod, self.domain.dom)
return [ (self.from_gf_dense(g), k) for g, k in factors ]
def gf_edf_zassenhaus(self, f, n):
factors = gf_edf_zassenhaus(self.to_gf_dense(f), self.domain.mod, self.domain.dom)
return [ self.from_gf_dense(g) for g in factors ]
def gf_ddf_shoup(self, f):
factors = gf_ddf_shoup(self.to_gf_dense(f), self.domain.mod, self.domain.dom)
return [ (self.from_gf_dense(g), k) for g, k in factors ]
def gf_edf_shoup(self, f, n):
factors = gf_edf_shoup(self.to_gf_dense(f), self.domain.mod, self.domain.dom)
return [ self.from_gf_dense(g) for g in factors ]
def gf_zassenhaus(self, f):
factors = gf_zassenhaus(self.to_gf_dense(f), self.domain.mod, self.domain.dom)
return [ self.from_gf_dense(g) for g in factors ]
def gf_shoup(self, f):
factors = gf_shoup(self.to_gf_dense(f), self.domain.mod, self.domain.dom)
return [ self.from_gf_dense(g) for g in factors ]
def gf_factor_sqf(self, f, method=None):
coeff, factors = gf_factor_sqf(self.to_gf_dense(f), self.domain.mod, self.domain.dom, method=method)
return coeff, [ self.from_gf_dense(g) for g in factors ]
def gf_factor(self, f):
coeff, factors = gf_factor(self.to_gf_dense(f), self.domain.mod, self.domain.dom)
return coeff, [ (self.from_gf_dense(g), k) for g, k in factors ]
PK ]ZZZV�om, m, sympy/polys/constructor.py"""Tools for constructing domains for expressions. """
from math import prod
from sympy.core import sympify
from sympy.core.evalf import pure_complex
from sympy.core.sorting import ordered
from sympy.polys.domains import ZZ, QQ, ZZ_I, QQ_I, EX
from sympy.polys.domains.complexfield import ComplexField
from sympy.polys.domains.realfield import RealField
from sympy.polys.polyoptions import build_options
from sympy.polys.polyutils import parallel_dict_from_basic
from sympy.utilities import public
def _construct_simple(coeffs, opt):
"""Handle simple domains, e.g.: ZZ, QQ, RR and algebraic domains. """
rationals = floats = complexes = algebraics = False
float_numbers = []
if opt.extension is True:
is_algebraic = lambda coeff: coeff.is_number and coeff.is_algebraic
else:
is_algebraic = lambda coeff: False
for coeff in coeffs:
if coeff.is_Rational:
if not coeff.is_Integer:
rationals = True
elif coeff.is_Float:
if algebraics:
# there are both reals and algebraics -> EX
return False
else:
floats = True
float_numbers.append(coeff)
else:
is_complex = pure_complex(coeff)
if is_complex:
complexes = True
x, y = is_complex
if x.is_Rational and y.is_Rational:
if not (x.is_Integer and y.is_Integer):
rationals = True
continue
else:
floats = True
if x.is_Float:
float_numbers.append(x)
if y.is_Float:
float_numbers.append(y)
elif is_algebraic(coeff):
if floats:
# there are both algebraics and reals -> EX
return False
algebraics = True
else:
# this is a composite domain, e.g. ZZ[X], EX
return None
# Use the maximum precision of all coefficients for the RR or CC
# precision
max_prec = max(c._prec for c in float_numbers) if float_numbers else 53
if algebraics:
domain, result = _construct_algebraic(coeffs, opt)
else:
if floats and complexes:
domain = ComplexField(prec=max_prec)
elif floats:
domain = RealField(prec=max_prec)
elif rationals or opt.field:
domain = QQ_I if complexes else QQ
else:
domain = ZZ_I if complexes else ZZ
result = [domain.from_sympy(coeff) for coeff in coeffs]
return domain, result
def _construct_algebraic(coeffs, opt):
"""We know that coefficients are algebraic so construct the extension. """
from sympy.polys.numberfields import primitive_element
exts = set()
def build_trees(args):
trees = []
for a in args:
if a.is_Rational:
tree = ('Q', QQ.from_sympy(a))
elif a.is_Add:
tree = ('+', build_trees(a.args))
elif a.is_Mul:
tree = ('*', build_trees(a.args))
else:
tree = ('e', a)
exts.add(a)
trees.append(tree)
return trees
trees = build_trees(coeffs)
exts = list(ordered(exts))
g, span, H = primitive_element(exts, ex=True, polys=True)
root = sum(s*ext for s, ext in zip(span, exts))
domain, g = QQ.algebraic_field((g, root)), g.rep.to_list()
exts_dom = [domain.dtype.from_list(h, g, QQ) for h in H]
exts_map = dict(zip(exts, exts_dom))
def convert_tree(tree):
op, args = tree
if op == 'Q':
return domain.dtype.from_list([args], g, QQ)
elif op == '+':
return sum((convert_tree(a) for a in args), domain.zero)
elif op == '*':
return prod(convert_tree(a) for a in args)
elif op == 'e':
return exts_map[args]
else:
raise RuntimeError
result = [convert_tree(tree) for tree in trees]
return domain, result
def _construct_composite(coeffs, opt):
"""Handle composite domains, e.g.: ZZ[X], QQ[X], ZZ(X), QQ(X). """
numers, denoms = [], []
for coeff in coeffs:
numer, denom = coeff.as_numer_denom()
numers.append(numer)
denoms.append(denom)
polys, gens = parallel_dict_from_basic(numers + denoms) # XXX: sorting
if not gens:
return None
if opt.composite is None:
if any(gen.is_number and gen.is_algebraic for gen in gens):
return None # generators are number-like so lets better use EX
all_symbols = set()
for gen in gens:
symbols = gen.free_symbols
if all_symbols & symbols:
return None # there could be algebraic relations between generators
else:
all_symbols |= symbols
n = len(gens)
k = len(polys)//2
numers = polys[:k]
denoms = polys[k:]
if opt.field:
fractions = True
else:
fractions, zeros = False, (0,)*n
for denom in denoms:
if len(denom) > 1 or zeros not in denom:
fractions = True
break
coeffs = set()
if not fractions:
for numer, denom in zip(numers, denoms):
denom = denom[zeros]
for monom, coeff in numer.items():
coeff /= denom
coeffs.add(coeff)
numer[monom] = coeff
else:
for numer, denom in zip(numers, denoms):
coeffs.update(list(numer.values()))
coeffs.update(list(denom.values()))
rationals = floats = complexes = False
float_numbers = []
for coeff in coeffs:
if coeff.is_Rational:
if not coeff.is_Integer:
rationals = True
elif coeff.is_Float:
floats = True
float_numbers.append(coeff)
else:
is_complex = pure_complex(coeff)
if is_complex is not None:
complexes = True
x, y = is_complex
if x.is_Rational and y.is_Rational:
if not (x.is_Integer and y.is_Integer):
rationals = True
else:
floats = True
if x.is_Float:
float_numbers.append(x)
if y.is_Float:
float_numbers.append(y)
max_prec = max(c._prec for c in float_numbers) if float_numbers else 53
if floats and complexes:
ground = ComplexField(prec=max_prec)
elif floats:
ground = RealField(prec=max_prec)
elif complexes:
if rationals:
ground = QQ_I
else:
ground = ZZ_I
elif rationals:
ground = QQ
else:
ground = ZZ
result = []
if not fractions:
domain = ground.poly_ring(*gens)
for numer in numers:
for monom, coeff in numer.items():
numer[monom] = ground.from_sympy(coeff)
result.append(domain(numer))
else:
domain = ground.frac_field(*gens)
for numer, denom in zip(numers, denoms):
for monom, coeff in numer.items():
numer[monom] = ground.from_sympy(coeff)
for monom, coeff in denom.items():
denom[monom] = ground.from_sympy(coeff)
result.append(domain((numer, denom)))
return domain, result
def _construct_expression(coeffs, opt):
"""The last resort case, i.e. use the expression domain. """
domain, result = EX, []
for coeff in coeffs:
result.append(domain.from_sympy(coeff))
return domain, result
@public
def construct_domain(obj, **args):
"""Construct a minimal domain for a list of expressions.
Explanation
===========
Given a list of normal SymPy expressions (of type :py:class:`~.Expr`)
``construct_domain`` will find a minimal :py:class:`~.Domain` that can
represent those expressions. The expressions will be converted to elements
of the domain and both the domain and the domain elements are returned.
Parameters
==========
obj: list or dict
The expressions to build a domain for.
**args: keyword arguments
Options that affect the choice of domain.
Returns
=======
(K, elements): Domain and list of domain elements
The domain K that can represent the expressions and the list or dict
of domain elements representing the same expressions as elements of K.
Examples
========
Given a list of :py:class:`~.Integer` ``construct_domain`` will return the
domain :ref:`ZZ` and a list of integers as elements of :ref:`ZZ`.
>>> from sympy import construct_domain, S
>>> expressions = [S(2), S(3), S(4)]
>>> K, elements = construct_domain(expressions)
>>> K
ZZ
>>> elements
[2, 3, 4]
>>> type(elements[0]) # doctest: +SKIP
<class 'int'>
>>> type(expressions[0])
<class 'sympy.core.numbers.Integer'>
If there are any :py:class:`~.Rational` then :ref:`QQ` is returned
instead.
>>> construct_domain([S(1)/2, S(3)/4])
(QQ, [1/2, 3/4])
If there are symbols then a polynomial ring :ref:`K[x]` is returned.
>>> from sympy import symbols
>>> x, y = symbols('x, y')
>>> construct_domain([2*x + 1, S(3)/4])
(QQ[x], [2*x + 1, 3/4])
>>> construct_domain([2*x + 1, y])
(ZZ[x,y], [2*x + 1, y])
If any symbols appear with negative powers then a rational function field
:ref:`K(x)` will be returned.
>>> construct_domain([y/x, x/(1 - y)])
(ZZ(x,y), [y/x, -x/(y - 1)])
Irrational algebraic numbers will result in the :ref:`EX` domain by
default. The keyword argument ``extension=True`` leads to the construction
of an algebraic number field :ref:`QQ(a)`.
>>> from sympy import sqrt
>>> construct_domain([sqrt(2)])
(EX, [EX(sqrt(2))])
>>> construct_domain([sqrt(2)], extension=True) # doctest: +SKIP
(QQ<sqrt(2)>, [ANP([1, 0], [1, 0, -2], QQ)])
See also
========
Domain
Expr
"""
opt = build_options(args)
if hasattr(obj, '__iter__'):
if isinstance(obj, dict):
if not obj:
monoms, coeffs = [], []
else:
monoms, coeffs = list(zip(*list(obj.items())))
else:
coeffs = obj
else:
coeffs = [obj]
coeffs = list(map(sympify, coeffs))
result = _construct_simple(coeffs, opt)
if result is not None:
if result is not False:
domain, coeffs = result
else:
domain, coeffs = _construct_expression(coeffs, opt)
else:
if opt.composite is False:
result = None
else:
result = _construct_composite(coeffs, opt)
if result is not None:
domain, coeffs = result
else:
domain, coeffs = _construct_expression(coeffs, opt)
if hasattr(obj, '__iter__'):
if isinstance(obj, dict):
return domain, dict(list(zip(monoms, coeffs)))
else:
return domain, coeffs
else:
return domain, coeffs[0]
PK ]ZZZ�/�0� 0� sympy/polys/densearith.py"""Arithmetics for dense recursive polynomials in ``K[x]`` or ``K[X]``. """
from sympy.polys.densebasic import (
dup_slice,
dup_LC, dmp_LC,
dup_degree, dmp_degree,
dup_strip, dmp_strip,
dmp_zero_p, dmp_zero,
dmp_one_p, dmp_one,
dmp_ground, dmp_zeros)
from sympy.polys.polyerrors import (ExactQuotientFailed, PolynomialDivisionFailed)
def dup_add_term(f, c, i, K):
"""
Add ``c*x**i`` to ``f`` in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_add_term(x**2 - 1, ZZ(2), 4)
2*x**4 + x**2 - 1
"""
if not c:
return f
n = len(f)
m = n - i - 1
if i == n - 1:
return dup_strip([f[0] + c] + f[1:])
else:
if i >= n:
return [c] + [K.zero]*(i - n) + f
else:
return f[:m] + [f[m] + c] + f[m + 1:]
def dmp_add_term(f, c, i, u, K):
"""
Add ``c(x_2..x_u)*x_0**i`` to ``f`` in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dmp_add_term(x*y + 1, 2, 2)
2*x**2 + x*y + 1
"""
if not u:
return dup_add_term(f, c, i, K)
v = u - 1
if dmp_zero_p(c, v):
return f
n = len(f)
m = n - i - 1
if i == n - 1:
return dmp_strip([dmp_add(f[0], c, v, K)] + f[1:], u)
else:
if i >= n:
return [c] + dmp_zeros(i - n, v, K) + f
else:
return f[:m] + [dmp_add(f[m], c, v, K)] + f[m + 1:]
def dup_sub_term(f, c, i, K):
"""
Subtract ``c*x**i`` from ``f`` in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_sub_term(2*x**4 + x**2 - 1, ZZ(2), 4)
x**2 - 1
"""
if not c:
return f
n = len(f)
m = n - i - 1
if i == n - 1:
return dup_strip([f[0] - c] + f[1:])
else:
if i >= n:
return [-c] + [K.zero]*(i - n) + f
else:
return f[:m] + [f[m] - c] + f[m + 1:]
def dmp_sub_term(f, c, i, u, K):
"""
Subtract ``c(x_2..x_u)*x_0**i`` from ``f`` in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dmp_sub_term(2*x**2 + x*y + 1, 2, 2)
x*y + 1
"""
if not u:
return dup_add_term(f, -c, i, K)
v = u - 1
if dmp_zero_p(c, v):
return f
n = len(f)
m = n - i - 1
if i == n - 1:
return dmp_strip([dmp_sub(f[0], c, v, K)] + f[1:], u)
else:
if i >= n:
return [dmp_neg(c, v, K)] + dmp_zeros(i - n, v, K) + f
else:
return f[:m] + [dmp_sub(f[m], c, v, K)] + f[m + 1:]
def dup_mul_term(f, c, i, K):
"""
Multiply ``f`` by ``c*x**i`` in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_mul_term(x**2 - 1, ZZ(3), 2)
3*x**4 - 3*x**2
"""
if not c or not f:
return []
else:
return [ cf * c for cf in f ] + [K.zero]*i
def dmp_mul_term(f, c, i, u, K):
"""
Multiply ``f`` by ``c(x_2..x_u)*x_0**i`` in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dmp_mul_term(x**2*y + x, 3*y, 2)
3*x**4*y**2 + 3*x**3*y
"""
if not u:
return dup_mul_term(f, c, i, K)
v = u - 1
if dmp_zero_p(f, u):
return f
if dmp_zero_p(c, v):
return dmp_zero(u)
else:
return [ dmp_mul(cf, c, v, K) for cf in f ] + dmp_zeros(i, v, K)
def dup_add_ground(f, c, K):
"""
Add an element of the ground domain to ``f``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_add_ground(x**3 + 2*x**2 + 3*x + 4, ZZ(4))
x**3 + 2*x**2 + 3*x + 8
"""
return dup_add_term(f, c, 0, K)
def dmp_add_ground(f, c, u, K):
"""
Add an element of the ground domain to ``f``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dmp_add_ground(x**3 + 2*x**2 + 3*x + 4, ZZ(4))
x**3 + 2*x**2 + 3*x + 8
"""
return dmp_add_term(f, dmp_ground(c, u - 1), 0, u, K)
def dup_sub_ground(f, c, K):
"""
Subtract an element of the ground domain from ``f``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_sub_ground(x**3 + 2*x**2 + 3*x + 4, ZZ(4))
x**3 + 2*x**2 + 3*x
"""
return dup_sub_term(f, c, 0, K)
def dmp_sub_ground(f, c, u, K):
"""
Subtract an element of the ground domain from ``f``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dmp_sub_ground(x**3 + 2*x**2 + 3*x + 4, ZZ(4))
x**3 + 2*x**2 + 3*x
"""
return dmp_sub_term(f, dmp_ground(c, u - 1), 0, u, K)
def dup_mul_ground(f, c, K):
"""
Multiply ``f`` by a constant value in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_mul_ground(x**2 + 2*x - 1, ZZ(3))
3*x**2 + 6*x - 3
"""
if not c or not f:
return []
else:
return [ cf * c for cf in f ]
def dmp_mul_ground(f, c, u, K):
"""
Multiply ``f`` by a constant value in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dmp_mul_ground(2*x + 2*y, ZZ(3))
6*x + 6*y
"""
if not u:
return dup_mul_ground(f, c, K)
v = u - 1
return [ dmp_mul_ground(cf, c, v, K) for cf in f ]
def dup_quo_ground(f, c, K):
"""
Quotient by a constant in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ, QQ
>>> R, x = ring("x", ZZ)
>>> R.dup_quo_ground(3*x**2 + 2, ZZ(2))
x**2 + 1
>>> R, x = ring("x", QQ)
>>> R.dup_quo_ground(3*x**2 + 2, QQ(2))
3/2*x**2 + 1
"""
if not c:
raise ZeroDivisionError('polynomial division')
if not f:
return f
if K.is_Field:
return [ K.quo(cf, c) for cf in f ]
else:
return [ cf // c for cf in f ]
def dmp_quo_ground(f, c, u, K):
"""
Quotient by a constant in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ, QQ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dmp_quo_ground(2*x**2*y + 3*x, ZZ(2))
x**2*y + x
>>> R, x,y = ring("x,y", QQ)
>>> R.dmp_quo_ground(2*x**2*y + 3*x, QQ(2))
x**2*y + 3/2*x
"""
if not u:
return dup_quo_ground(f, c, K)
v = u - 1
return [ dmp_quo_ground(cf, c, v, K) for cf in f ]
def dup_exquo_ground(f, c, K):
"""
Exact quotient by a constant in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, QQ
>>> R, x = ring("x", QQ)
>>> R.dup_exquo_ground(x**2 + 2, QQ(2))
1/2*x**2 + 1
"""
if not c:
raise ZeroDivisionError('polynomial division')
if not f:
return f
return [ K.exquo(cf, c) for cf in f ]
def dmp_exquo_ground(f, c, u, K):
"""
Exact quotient by a constant in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, QQ
>>> R, x,y = ring("x,y", QQ)
>>> R.dmp_exquo_ground(x**2*y + 2*x, QQ(2))
1/2*x**2*y + x
"""
if not u:
return dup_exquo_ground(f, c, K)
v = u - 1
return [ dmp_exquo_ground(cf, c, v, K) for cf in f ]
def dup_lshift(f, n, K):
"""
Efficiently multiply ``f`` by ``x**n`` in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_lshift(x**2 + 1, 2)
x**4 + x**2
"""
if not f:
return f
else:
return f + [K.zero]*n
def dup_rshift(f, n, K):
"""
Efficiently divide ``f`` by ``x**n`` in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_rshift(x**4 + x**2, 2)
x**2 + 1
>>> R.dup_rshift(x**4 + x**2 + 2, 2)
x**2 + 1
"""
return f[:-n]
def dup_abs(f, K):
"""
Make all coefficients positive in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_abs(x**2 - 1)
x**2 + 1
"""
return [ K.abs(coeff) for coeff in f ]
def dmp_abs(f, u, K):
"""
Make all coefficients positive in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dmp_abs(x**2*y - x)
x**2*y + x
"""
if not u:
return dup_abs(f, K)
v = u - 1
return [ dmp_abs(cf, v, K) for cf in f ]
def dup_neg(f, K):
"""
Negate a polynomial in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_neg(x**2 - 1)
-x**2 + 1
"""
return [ -coeff for coeff in f ]
def dmp_neg(f, u, K):
"""
Negate a polynomial in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dmp_neg(x**2*y - x)
-x**2*y + x
"""
if not u:
return dup_neg(f, K)
v = u - 1
return [ dmp_neg(cf, v, K) for cf in f ]
def dup_add(f, g, K):
"""
Add dense polynomials in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_add(x**2 - 1, x - 2)
x**2 + x - 3
"""
if not f:
return g
if not g:
return f
df = dup_degree(f)
dg = dup_degree(g)
if df == dg:
return dup_strip([ a + b for a, b in zip(f, g) ])
else:
k = abs(df - dg)
if df > dg:
h, f = f[:k], f[k:]
else:
h, g = g[:k], g[k:]
return h + [ a + b for a, b in zip(f, g) ]
def dmp_add(f, g, u, K):
"""
Add dense polynomials in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dmp_add(x**2 + y, x**2*y + x)
x**2*y + x**2 + x + y
"""
if not u:
return dup_add(f, g, K)
df = dmp_degree(f, u)
if df < 0:
return g
dg = dmp_degree(g, u)
if dg < 0:
return f
v = u - 1
if df == dg:
return dmp_strip([ dmp_add(a, b, v, K) for a, b in zip(f, g) ], u)
else:
k = abs(df - dg)
if df > dg:
h, f = f[:k], f[k:]
else:
h, g = g[:k], g[k:]
return h + [ dmp_add(a, b, v, K) for a, b in zip(f, g) ]
def dup_sub(f, g, K):
"""
Subtract dense polynomials in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_sub(x**2 - 1, x - 2)
x**2 - x + 1
"""
if not f:
return dup_neg(g, K)
if not g:
return f
df = dup_degree(f)
dg = dup_degree(g)
if df == dg:
return dup_strip([ a - b for a, b in zip(f, g) ])
else:
k = abs(df - dg)
if df > dg:
h, f = f[:k], f[k:]
else:
h, g = dup_neg(g[:k], K), g[k:]
return h + [ a - b for a, b in zip(f, g) ]
def dmp_sub(f, g, u, K):
"""
Subtract dense polynomials in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dmp_sub(x**2 + y, x**2*y + x)
-x**2*y + x**2 - x + y
"""
if not u:
return dup_sub(f, g, K)
df = dmp_degree(f, u)
if df < 0:
return dmp_neg(g, u, K)
dg = dmp_degree(g, u)
if dg < 0:
return f
v = u - 1
if df == dg:
return dmp_strip([ dmp_sub(a, b, v, K) for a, b in zip(f, g) ], u)
else:
k = abs(df - dg)
if df > dg:
h, f = f[:k], f[k:]
else:
h, g = dmp_neg(g[:k], u, K), g[k:]
return h + [ dmp_sub(a, b, v, K) for a, b in zip(f, g) ]
def dup_add_mul(f, g, h, K):
"""
Returns ``f + g*h`` where ``f, g, h`` are in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_add_mul(x**2 - 1, x - 2, x + 2)
2*x**2 - 5
"""
return dup_add(f, dup_mul(g, h, K), K)
def dmp_add_mul(f, g, h, u, K):
"""
Returns ``f + g*h`` where ``f, g, h`` are in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dmp_add_mul(x**2 + y, x, x + 2)
2*x**2 + 2*x + y
"""
return dmp_add(f, dmp_mul(g, h, u, K), u, K)
def dup_sub_mul(f, g, h, K):
"""
Returns ``f - g*h`` where ``f, g, h`` are in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_sub_mul(x**2 - 1, x - 2, x + 2)
3
"""
return dup_sub(f, dup_mul(g, h, K), K)
def dmp_sub_mul(f, g, h, u, K):
"""
Returns ``f - g*h`` where ``f, g, h`` are in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dmp_sub_mul(x**2 + y, x, x + 2)
-2*x + y
"""
return dmp_sub(f, dmp_mul(g, h, u, K), u, K)
def dup_mul(f, g, K):
"""
Multiply dense polynomials in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_mul(x - 2, x + 2)
x**2 - 4
"""
if f == g:
return dup_sqr(f, K)
if not (f and g):
return []
df = dup_degree(f)
dg = dup_degree(g)
n = max(df, dg) + 1
if n < 100:
h = []
for i in range(0, df + dg + 1):
coeff = K.zero
for j in range(max(0, i - dg), min(df, i) + 1):
coeff += f[j]*g[i - j]
h.append(coeff)
return dup_strip(h)
else:
# Use Karatsuba's algorithm (divide and conquer), see e.g.:
# Joris van der Hoeven, Relax But Don't Be Too Lazy,
# J. Symbolic Computation, 11 (2002), section 3.1.1.
n2 = n//2
fl, gl = dup_slice(f, 0, n2, K), dup_slice(g, 0, n2, K)
fh = dup_rshift(dup_slice(f, n2, n, K), n2, K)
gh = dup_rshift(dup_slice(g, n2, n, K), n2, K)
lo, hi = dup_mul(fl, gl, K), dup_mul(fh, gh, K)
mid = dup_mul(dup_add(fl, fh, K), dup_add(gl, gh, K), K)
mid = dup_sub(mid, dup_add(lo, hi, K), K)
return dup_add(dup_add(lo, dup_lshift(mid, n2, K), K),
dup_lshift(hi, 2*n2, K), K)
def dmp_mul(f, g, u, K):
"""
Multiply dense polynomials in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dmp_mul(x*y + 1, x)
x**2*y + x
"""
if not u:
return dup_mul(f, g, K)
if f == g:
return dmp_sqr(f, u, K)
df = dmp_degree(f, u)
if df < 0:
return f
dg = dmp_degree(g, u)
if dg < 0:
return g
h, v = [], u - 1
for i in range(0, df + dg + 1):
coeff = dmp_zero(v)
for j in range(max(0, i - dg), min(df, i) + 1):
coeff = dmp_add(coeff, dmp_mul(f[j], g[i - j], v, K), v, K)
h.append(coeff)
return dmp_strip(h, u)
def dup_sqr(f, K):
"""
Square dense polynomials in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_sqr(x**2 + 1)
x**4 + 2*x**2 + 1
"""
df, h = len(f) - 1, []
for i in range(0, 2*df + 1):
c = K.zero
jmin = max(0, i - df)
jmax = min(i, df)
n = jmax - jmin + 1
jmax = jmin + n // 2 - 1
for j in range(jmin, jmax + 1):
c += f[j]*f[i - j]
c += c
if n & 1:
elem = f[jmax + 1]
c += elem**2
h.append(c)
return dup_strip(h)
def dmp_sqr(f, u, K):
"""
Square dense polynomials in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dmp_sqr(x**2 + x*y + y**2)
x**4 + 2*x**3*y + 3*x**2*y**2 + 2*x*y**3 + y**4
"""
if not u:
return dup_sqr(f, K)
df = dmp_degree(f, u)
if df < 0:
return f
h, v = [], u - 1
for i in range(0, 2*df + 1):
c = dmp_zero(v)
jmin = max(0, i - df)
jmax = min(i, df)
n = jmax - jmin + 1
jmax = jmin + n // 2 - 1
for j in range(jmin, jmax + 1):
c = dmp_add(c, dmp_mul(f[j], f[i - j], v, K), v, K)
c = dmp_mul_ground(c, K(2), v, K)
if n & 1:
elem = dmp_sqr(f[jmax + 1], v, K)
c = dmp_add(c, elem, v, K)
h.append(c)
return dmp_strip(h, u)
def dup_pow(f, n, K):
"""
Raise ``f`` to the ``n``-th power in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_pow(x - 2, 3)
x**3 - 6*x**2 + 12*x - 8
"""
if not n:
return [K.one]
if n < 0:
raise ValueError("Cannot raise polynomial to a negative power")
if n == 1 or not f or f == [K.one]:
return f
g = [K.one]
while True:
n, m = n//2, n
if m % 2:
g = dup_mul(g, f, K)
if not n:
break
f = dup_sqr(f, K)
return g
def dmp_pow(f, n, u, K):
"""
Raise ``f`` to the ``n``-th power in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dmp_pow(x*y + 1, 3)
x**3*y**3 + 3*x**2*y**2 + 3*x*y + 1
"""
if not u:
return dup_pow(f, n, K)
if not n:
return dmp_one(u, K)
if n < 0:
raise ValueError("Cannot raise polynomial to a negative power")
if n == 1 or dmp_zero_p(f, u) or dmp_one_p(f, u, K):
return f
g = dmp_one(u, K)
while True:
n, m = n//2, n
if m & 1:
g = dmp_mul(g, f, u, K)
if not n:
break
f = dmp_sqr(f, u, K)
return g
def dup_pdiv(f, g, K):
"""
Polynomial pseudo-division in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_pdiv(x**2 + 1, 2*x - 4)
(2*x + 4, 20)
"""
df = dup_degree(f)
dg = dup_degree(g)
q, r, dr = [], f, df
if not g:
raise ZeroDivisionError("polynomial division")
elif df < dg:
return q, r
N = df - dg + 1
lc_g = dup_LC(g, K)
while True:
lc_r = dup_LC(r, K)
j, N = dr - dg, N - 1
Q = dup_mul_ground(q, lc_g, K)
q = dup_add_term(Q, lc_r, j, K)
R = dup_mul_ground(r, lc_g, K)
G = dup_mul_term(g, lc_r, j, K)
r = dup_sub(R, G, K)
_dr, dr = dr, dup_degree(r)
if dr < dg:
break
elif not (dr < _dr):
raise PolynomialDivisionFailed(f, g, K)
c = lc_g**N
q = dup_mul_ground(q, c, K)
r = dup_mul_ground(r, c, K)
return q, r
def dup_prem(f, g, K):
"""
Polynomial pseudo-remainder in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_prem(x**2 + 1, 2*x - 4)
20
"""
df = dup_degree(f)
dg = dup_degree(g)
r, dr = f, df
if not g:
raise ZeroDivisionError("polynomial division")
elif df < dg:
return r
N = df - dg + 1
lc_g = dup_LC(g, K)
while True:
lc_r = dup_LC(r, K)
j, N = dr - dg, N - 1
R = dup_mul_ground(r, lc_g, K)
G = dup_mul_term(g, lc_r, j, K)
r = dup_sub(R, G, K)
_dr, dr = dr, dup_degree(r)
if dr < dg:
break
elif not (dr < _dr):
raise PolynomialDivisionFailed(f, g, K)
return dup_mul_ground(r, lc_g**N, K)
def dup_pquo(f, g, K):
"""
Polynomial exact pseudo-quotient in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_pquo(x**2 - 1, 2*x - 2)
2*x + 2
>>> R.dup_pquo(x**2 + 1, 2*x - 4)
2*x + 4
"""
return dup_pdiv(f, g, K)[0]
def dup_pexquo(f, g, K):
"""
Polynomial pseudo-quotient in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_pexquo(x**2 - 1, 2*x - 2)
2*x + 2
>>> R.dup_pexquo(x**2 + 1, 2*x - 4)
Traceback (most recent call last):
...
ExactQuotientFailed: [2, -4] does not divide [1, 0, 1]
"""
q, r = dup_pdiv(f, g, K)
if not r:
return q
else:
raise ExactQuotientFailed(f, g)
def dmp_pdiv(f, g, u, K):
"""
Polynomial pseudo-division in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dmp_pdiv(x**2 + x*y, 2*x + 2)
(2*x + 2*y - 2, -4*y + 4)
"""
if not u:
return dup_pdiv(f, g, K)
df = dmp_degree(f, u)
dg = dmp_degree(g, u)
if dg < 0:
raise ZeroDivisionError("polynomial division")
q, r, dr = dmp_zero(u), f, df
if df < dg:
return q, r
N = df - dg + 1
lc_g = dmp_LC(g, K)
while True:
lc_r = dmp_LC(r, K)
j, N = dr - dg, N - 1
Q = dmp_mul_term(q, lc_g, 0, u, K)
q = dmp_add_term(Q, lc_r, j, u, K)
R = dmp_mul_term(r, lc_g, 0, u, K)
G = dmp_mul_term(g, lc_r, j, u, K)
r = dmp_sub(R, G, u, K)
_dr, dr = dr, dmp_degree(r, u)
if dr < dg:
break
elif not (dr < _dr):
raise PolynomialDivisionFailed(f, g, K)
c = dmp_pow(lc_g, N, u - 1, K)
q = dmp_mul_term(q, c, 0, u, K)
r = dmp_mul_term(r, c, 0, u, K)
return q, r
def dmp_prem(f, g, u, K):
"""
Polynomial pseudo-remainder in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dmp_prem(x**2 + x*y, 2*x + 2)
-4*y + 4
"""
if not u:
return dup_prem(f, g, K)
df = dmp_degree(f, u)
dg = dmp_degree(g, u)
if dg < 0:
raise ZeroDivisionError("polynomial division")
r, dr = f, df
if df < dg:
return r
N = df - dg + 1
lc_g = dmp_LC(g, K)
while True:
lc_r = dmp_LC(r, K)
j, N = dr - dg, N - 1
R = dmp_mul_term(r, lc_g, 0, u, K)
G = dmp_mul_term(g, lc_r, j, u, K)
r = dmp_sub(R, G, u, K)
_dr, dr = dr, dmp_degree(r, u)
if dr < dg:
break
elif not (dr < _dr):
raise PolynomialDivisionFailed(f, g, K)
c = dmp_pow(lc_g, N, u - 1, K)
return dmp_mul_term(r, c, 0, u, K)
def dmp_pquo(f, g, u, K):
"""
Polynomial exact pseudo-quotient in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> f = x**2 + x*y
>>> g = 2*x + 2*y
>>> h = 2*x + 2
>>> R.dmp_pquo(f, g)
2*x
>>> R.dmp_pquo(f, h)
2*x + 2*y - 2
"""
return dmp_pdiv(f, g, u, K)[0]
def dmp_pexquo(f, g, u, K):
"""
Polynomial pseudo-quotient in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> f = x**2 + x*y
>>> g = 2*x + 2*y
>>> h = 2*x + 2
>>> R.dmp_pexquo(f, g)
2*x
>>> R.dmp_pexquo(f, h)
Traceback (most recent call last):
...
ExactQuotientFailed: [[2], [2]] does not divide [[1], [1, 0], []]
"""
q, r = dmp_pdiv(f, g, u, K)
if dmp_zero_p(r, u):
return q
else:
raise ExactQuotientFailed(f, g)
def dup_rr_div(f, g, K):
"""
Univariate division with remainder over a ring.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_rr_div(x**2 + 1, 2*x - 4)
(0, x**2 + 1)
"""
df = dup_degree(f)
dg = dup_degree(g)
q, r, dr = [], f, df
if not g:
raise ZeroDivisionError("polynomial division")
elif df < dg:
return q, r
lc_g = dup_LC(g, K)
while True:
lc_r = dup_LC(r, K)
if lc_r % lc_g:
break
c = K.exquo(lc_r, lc_g)
j = dr - dg
q = dup_add_term(q, c, j, K)
h = dup_mul_term(g, c, j, K)
r = dup_sub(r, h, K)
_dr, dr = dr, dup_degree(r)
if dr < dg:
break
elif not (dr < _dr):
raise PolynomialDivisionFailed(f, g, K)
return q, r
def dmp_rr_div(f, g, u, K):
"""
Multivariate division with remainder over a ring.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dmp_rr_div(x**2 + x*y, 2*x + 2)
(0, x**2 + x*y)
"""
if not u:
return dup_rr_div(f, g, K)
df = dmp_degree(f, u)
dg = dmp_degree(g, u)
if dg < 0:
raise ZeroDivisionError("polynomial division")
q, r, dr = dmp_zero(u), f, df
if df < dg:
return q, r
lc_g, v = dmp_LC(g, K), u - 1
while True:
lc_r = dmp_LC(r, K)
c, R = dmp_rr_div(lc_r, lc_g, v, K)
if not dmp_zero_p(R, v):
break
j = dr - dg
q = dmp_add_term(q, c, j, u, K)
h = dmp_mul_term(g, c, j, u, K)
r = dmp_sub(r, h, u, K)
_dr, dr = dr, dmp_degree(r, u)
if dr < dg:
break
elif not (dr < _dr):
raise PolynomialDivisionFailed(f, g, K)
return q, r
def dup_ff_div(f, g, K):
"""
Polynomial division with remainder over a field.
Examples
========
>>> from sympy.polys import ring, QQ
>>> R, x = ring("x", QQ)
>>> R.dup_ff_div(x**2 + 1, 2*x - 4)
(1/2*x + 1, 5)
"""
df = dup_degree(f)
dg = dup_degree(g)
q, r, dr = [], f, df
if not g:
raise ZeroDivisionError("polynomial division")
elif df < dg:
return q, r
lc_g = dup_LC(g, K)
while True:
lc_r = dup_LC(r, K)
c = K.exquo(lc_r, lc_g)
j = dr - dg
q = dup_add_term(q, c, j, K)
h = dup_mul_term(g, c, j, K)
r = dup_sub(r, h, K)
_dr, dr = dr, dup_degree(r)
if dr < dg:
break
elif dr == _dr and not K.is_Exact:
# remove leading term created by rounding error
r = dup_strip(r[1:])
dr = dup_degree(r)
if dr < dg:
break
elif not (dr < _dr):
raise PolynomialDivisionFailed(f, g, K)
return q, r
def dmp_ff_div(f, g, u, K):
"""
Polynomial division with remainder over a field.
Examples
========
>>> from sympy.polys import ring, QQ
>>> R, x,y = ring("x,y", QQ)
>>> R.dmp_ff_div(x**2 + x*y, 2*x + 2)
(1/2*x + 1/2*y - 1/2, -y + 1)
"""
if not u:
return dup_ff_div(f, g, K)
df = dmp_degree(f, u)
dg = dmp_degree(g, u)
if dg < 0:
raise ZeroDivisionError("polynomial division")
q, r, dr = dmp_zero(u), f, df
if df < dg:
return q, r
lc_g, v = dmp_LC(g, K), u - 1
while True:
lc_r = dmp_LC(r, K)
c, R = dmp_ff_div(lc_r, lc_g, v, K)
if not dmp_zero_p(R, v):
break
j = dr - dg
q = dmp_add_term(q, c, j, u, K)
h = dmp_mul_term(g, c, j, u, K)
r = dmp_sub(r, h, u, K)
_dr, dr = dr, dmp_degree(r, u)
if dr < dg:
break
elif not (dr < _dr):
raise PolynomialDivisionFailed(f, g, K)
return q, r
def dup_div(f, g, K):
"""
Polynomial division with remainder in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ, QQ
>>> R, x = ring("x", ZZ)
>>> R.dup_div(x**2 + 1, 2*x - 4)
(0, x**2 + 1)
>>> R, x = ring("x", QQ)
>>> R.dup_div(x**2 + 1, 2*x - 4)
(1/2*x + 1, 5)
"""
if K.is_Field:
return dup_ff_div(f, g, K)
else:
return dup_rr_div(f, g, K)
def dup_rem(f, g, K):
"""
Returns polynomial remainder in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ, QQ
>>> R, x = ring("x", ZZ)
>>> R.dup_rem(x**2 + 1, 2*x - 4)
x**2 + 1
>>> R, x = ring("x", QQ)
>>> R.dup_rem(x**2 + 1, 2*x - 4)
5
"""
return dup_div(f, g, K)[1]
def dup_quo(f, g, K):
"""
Returns exact polynomial quotient in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ, QQ
>>> R, x = ring("x", ZZ)
>>> R.dup_quo(x**2 + 1, 2*x - 4)
0
>>> R, x = ring("x", QQ)
>>> R.dup_quo(x**2 + 1, 2*x - 4)
1/2*x + 1
"""
return dup_div(f, g, K)[0]
def dup_exquo(f, g, K):
"""
Returns polynomial quotient in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_exquo(x**2 - 1, x - 1)
x + 1
>>> R.dup_exquo(x**2 + 1, 2*x - 4)
Traceback (most recent call last):
...
ExactQuotientFailed: [2, -4] does not divide [1, 0, 1]
"""
q, r = dup_div(f, g, K)
if not r:
return q
else:
raise ExactQuotientFailed(f, g)
def dmp_div(f, g, u, K):
"""
Polynomial division with remainder in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ, QQ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dmp_div(x**2 + x*y, 2*x + 2)
(0, x**2 + x*y)
>>> R, x,y = ring("x,y", QQ)
>>> R.dmp_div(x**2 + x*y, 2*x + 2)
(1/2*x + 1/2*y - 1/2, -y + 1)
"""
if K.is_Field:
return dmp_ff_div(f, g, u, K)
else:
return dmp_rr_div(f, g, u, K)
def dmp_rem(f, g, u, K):
"""
Returns polynomial remainder in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ, QQ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dmp_rem(x**2 + x*y, 2*x + 2)
x**2 + x*y
>>> R, x,y = ring("x,y", QQ)
>>> R.dmp_rem(x**2 + x*y, 2*x + 2)
-y + 1
"""
return dmp_div(f, g, u, K)[1]
def dmp_quo(f, g, u, K):
"""
Returns exact polynomial quotient in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ, QQ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dmp_quo(x**2 + x*y, 2*x + 2)
0
>>> R, x,y = ring("x,y", QQ)
>>> R.dmp_quo(x**2 + x*y, 2*x + 2)
1/2*x + 1/2*y - 1/2
"""
return dmp_div(f, g, u, K)[0]
def dmp_exquo(f, g, u, K):
"""
Returns polynomial quotient in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> f = x**2 + x*y
>>> g = x + y
>>> h = 2*x + 2
>>> R.dmp_exquo(f, g)
x
>>> R.dmp_exquo(f, h)
Traceback (most recent call last):
...
ExactQuotientFailed: [[2], [2]] does not divide [[1], [1, 0], []]
"""
q, r = dmp_div(f, g, u, K)
if dmp_zero_p(r, u):
return q
else:
raise ExactQuotientFailed(f, g)
def dup_max_norm(f, K):
"""
Returns maximum norm of a polynomial in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_max_norm(-x**2 + 2*x - 3)
3
"""
if not f:
return K.zero
else:
return max(dup_abs(f, K))
def dmp_max_norm(f, u, K):
"""
Returns maximum norm of a polynomial in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dmp_max_norm(2*x*y - x - 3)
3
"""
if not u:
return dup_max_norm(f, K)
v = u - 1
return max(dmp_max_norm(c, v, K) for c in f)
def dup_l1_norm(f, K):
"""
Returns l1 norm of a polynomial in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_l1_norm(2*x**3 - 3*x**2 + 1)
6
"""
if not f:
return K.zero
else:
return sum(dup_abs(f, K))
def dmp_l1_norm(f, u, K):
"""
Returns l1 norm of a polynomial in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dmp_l1_norm(2*x*y - x - 3)
6
"""
if not u:
return dup_l1_norm(f, K)
v = u - 1
return sum(dmp_l1_norm(c, v, K) for c in f)
def dup_l2_norm_squared(f, K):
"""
Returns squared l2 norm of a polynomial in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_l2_norm_squared(2*x**3 - 3*x**2 + 1)
14
"""
return sum([coeff**2 for coeff in f], K.zero)
def dmp_l2_norm_squared(f, u, K):
"""
Returns squared l2 norm of a polynomial in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dmp_l2_norm_squared(2*x*y - x - 3)
14
"""
if not u:
return dup_l2_norm_squared(f, K)
v = u - 1
return sum(dmp_l2_norm_squared(c, v, K) for c in f)
def dup_expand(polys, K):
"""
Multiply together several polynomials in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_expand([x**2 - 1, x, 2])
2*x**3 - 2*x
"""
if not polys:
return [K.one]
f = polys[0]
for g in polys[1:]:
f = dup_mul(f, g, K)
return f
def dmp_expand(polys, u, K):
"""
Multiply together several polynomials in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dmp_expand([x**2 + y**2, x + 1])
x**3 + x**2 + x*y**2 + y**2
"""
if not polys:
return dmp_one(u, K)
f = polys[0]
for g in polys[1:]:
f = dmp_mul(f, g, u, K)
return f
PK ]ZZZN���r� r� sympy/polys/densebasic.py"""Basic tools for dense recursive polynomials in ``K[x]`` or ``K[X]``. """
from sympy.core import igcd
from sympy.polys.monomials import monomial_min, monomial_div
from sympy.polys.orderings import monomial_key
import random
ninf = float('-inf')
def poly_LC(f, K):
"""
Return leading coefficient of ``f``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import poly_LC
>>> poly_LC([], ZZ)
0
>>> poly_LC([ZZ(1), ZZ(2), ZZ(3)], ZZ)
1
"""
if not f:
return K.zero
else:
return f[0]
def poly_TC(f, K):
"""
Return trailing coefficient of ``f``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import poly_TC
>>> poly_TC([], ZZ)
0
>>> poly_TC([ZZ(1), ZZ(2), ZZ(3)], ZZ)
3
"""
if not f:
return K.zero
else:
return f[-1]
dup_LC = dmp_LC = poly_LC
dup_TC = dmp_TC = poly_TC
def dmp_ground_LC(f, u, K):
"""
Return the ground leading coefficient.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_ground_LC
>>> f = ZZ.map([[[1], [2, 3]]])
>>> dmp_ground_LC(f, 2, ZZ)
1
"""
while u:
f = dmp_LC(f, K)
u -= 1
return dup_LC(f, K)
def dmp_ground_TC(f, u, K):
"""
Return the ground trailing coefficient.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_ground_TC
>>> f = ZZ.map([[[1], [2, 3]]])
>>> dmp_ground_TC(f, 2, ZZ)
3
"""
while u:
f = dmp_TC(f, K)
u -= 1
return dup_TC(f, K)
def dmp_true_LT(f, u, K):
"""
Return the leading term ``c * x_1**n_1 ... x_k**n_k``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_true_LT
>>> f = ZZ.map([[4], [2, 0], [3, 0, 0]])
>>> dmp_true_LT(f, 1, ZZ)
((2, 0), 4)
"""
monom = []
while u:
monom.append(len(f) - 1)
f, u = f[0], u - 1
if not f:
monom.append(0)
else:
monom.append(len(f) - 1)
return tuple(monom), dup_LC(f, K)
def dup_degree(f):
"""
Return the leading degree of ``f`` in ``K[x]``.
Note that the degree of 0 is negative infinity (``float('-inf')``).
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dup_degree
>>> f = ZZ.map([1, 2, 0, 3])
>>> dup_degree(f)
3
"""
if not f:
return ninf
return len(f) - 1
def dmp_degree(f, u):
"""
Return the leading degree of ``f`` in ``x_0`` in ``K[X]``.
Note that the degree of 0 is negative infinity (``float('-inf')``).
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_degree
>>> dmp_degree([[[]]], 2)
-inf
>>> f = ZZ.map([[2], [1, 2, 3]])
>>> dmp_degree(f, 1)
1
"""
if dmp_zero_p(f, u):
return ninf
else:
return len(f) - 1
def _rec_degree_in(g, v, i, j):
"""Recursive helper function for :func:`dmp_degree_in`."""
if i == j:
return dmp_degree(g, v)
v, i = v - 1, i + 1
return max(_rec_degree_in(c, v, i, j) for c in g)
def dmp_degree_in(f, j, u):
"""
Return the leading degree of ``f`` in ``x_j`` in ``K[X]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_degree_in
>>> f = ZZ.map([[2], [1, 2, 3]])
>>> dmp_degree_in(f, 0, 1)
1
>>> dmp_degree_in(f, 1, 1)
2
"""
if not j:
return dmp_degree(f, u)
if j < 0 or j > u:
raise IndexError("0 <= j <= %s expected, got %s" % (u, j))
return _rec_degree_in(f, u, 0, j)
def _rec_degree_list(g, v, i, degs):
"""Recursive helper for :func:`dmp_degree_list`."""
degs[i] = max(degs[i], dmp_degree(g, v))
if v > 0:
v, i = v - 1, i + 1
for c in g:
_rec_degree_list(c, v, i, degs)
def dmp_degree_list(f, u):
"""
Return a list of degrees of ``f`` in ``K[X]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_degree_list
>>> f = ZZ.map([[1], [1, 2, 3]])
>>> dmp_degree_list(f, 1)
(1, 2)
"""
degs = [ninf]*(u + 1)
_rec_degree_list(f, u, 0, degs)
return tuple(degs)
def dup_strip(f):
"""
Remove leading zeros from ``f`` in ``K[x]``.
Examples
========
>>> from sympy.polys.densebasic import dup_strip
>>> dup_strip([0, 0, 1, 2, 3, 0])
[1, 2, 3, 0]
"""
if not f or f[0]:
return f
i = 0
for cf in f:
if cf:
break
else:
i += 1
return f[i:]
def dmp_strip(f, u):
"""
Remove leading zeros from ``f`` in ``K[X]``.
Examples
========
>>> from sympy.polys.densebasic import dmp_strip
>>> dmp_strip([[], [0, 1, 2], [1]], 1)
[[0, 1, 2], [1]]
"""
if not u:
return dup_strip(f)
if dmp_zero_p(f, u):
return f
i, v = 0, u - 1
for c in f:
if not dmp_zero_p(c, v):
break
else:
i += 1
if i == len(f):
return dmp_zero(u)
else:
return f[i:]
def _rec_validate(f, g, i, K):
"""Recursive helper for :func:`dmp_validate`."""
if not isinstance(g, list):
if K is not None and not K.of_type(g):
raise TypeError("%s in %s in not of type %s" % (g, f, K.dtype))
return {i - 1}
elif not g:
return {i}
else:
levels = set()
for c in g:
levels |= _rec_validate(f, c, i + 1, K)
return levels
def _rec_strip(g, v):
"""Recursive helper for :func:`_rec_strip`."""
if not v:
return dup_strip(g)
w = v - 1
return dmp_strip([ _rec_strip(c, w) for c in g ], v)
def dmp_validate(f, K=None):
"""
Return the number of levels in ``f`` and recursively strip it.
Examples
========
>>> from sympy.polys.densebasic import dmp_validate
>>> dmp_validate([[], [0, 1, 2], [1]])
([[1, 2], [1]], 1)
>>> dmp_validate([[1], 1])
Traceback (most recent call last):
...
ValueError: invalid data structure for a multivariate polynomial
"""
levels = _rec_validate(f, f, 0, K)
u = levels.pop()
if not levels:
return _rec_strip(f, u), u
else:
raise ValueError(
"invalid data structure for a multivariate polynomial")
def dup_reverse(f):
"""
Compute ``x**n * f(1/x)``, i.e.: reverse ``f`` in ``K[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dup_reverse
>>> f = ZZ.map([1, 2, 3, 0])
>>> dup_reverse(f)
[3, 2, 1]
"""
return dup_strip(list(reversed(f)))
def dup_copy(f):
"""
Create a new copy of a polynomial ``f`` in ``K[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dup_copy
>>> f = ZZ.map([1, 2, 3, 0])
>>> dup_copy([1, 2, 3, 0])
[1, 2, 3, 0]
"""
return list(f)
def dmp_copy(f, u):
"""
Create a new copy of a polynomial ``f`` in ``K[X]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_copy
>>> f = ZZ.map([[1], [1, 2]])
>>> dmp_copy(f, 1)
[[1], [1, 2]]
"""
if not u:
return list(f)
v = u - 1
return [ dmp_copy(c, v) for c in f ]
def dup_to_tuple(f):
"""
Convert `f` into a tuple.
This is needed for hashing. This is similar to dup_copy().
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dup_copy
>>> f = ZZ.map([1, 2, 3, 0])
>>> dup_copy([1, 2, 3, 0])
[1, 2, 3, 0]
"""
return tuple(f)
def dmp_to_tuple(f, u):
"""
Convert `f` into a nested tuple of tuples.
This is needed for hashing. This is similar to dmp_copy().
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_to_tuple
>>> f = ZZ.map([[1], [1, 2]])
>>> dmp_to_tuple(f, 1)
((1,), (1, 2))
"""
if not u:
return tuple(f)
v = u - 1
return tuple(dmp_to_tuple(c, v) for c in f)
def dup_normal(f, K):
"""
Normalize univariate polynomial in the given domain.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dup_normal
>>> dup_normal([0, 1, 2, 3], ZZ)
[1, 2, 3]
"""
return dup_strip([ K.normal(c) for c in f ])
def dmp_normal(f, u, K):
"""
Normalize a multivariate polynomial in the given domain.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_normal
>>> dmp_normal([[], [0, 1, 2]], 1, ZZ)
[[1, 2]]
"""
if not u:
return dup_normal(f, K)
v = u - 1
return dmp_strip([ dmp_normal(c, v, K) for c in f ], u)
def dup_convert(f, K0, K1):
"""
Convert the ground domain of ``f`` from ``K0`` to ``K1``.
Examples
========
>>> from sympy.polys.rings import ring
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dup_convert
>>> R, x = ring("x", ZZ)
>>> dup_convert([R(1), R(2)], R.to_domain(), ZZ)
[1, 2]
>>> dup_convert([ZZ(1), ZZ(2)], ZZ, R.to_domain())
[1, 2]
"""
if K0 is not None and K0 == K1:
return f
else:
return dup_strip([ K1.convert(c, K0) for c in f ])
def dmp_convert(f, u, K0, K1):
"""
Convert the ground domain of ``f`` from ``K0`` to ``K1``.
Examples
========
>>> from sympy.polys.rings import ring
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_convert
>>> R, x = ring("x", ZZ)
>>> dmp_convert([[R(1)], [R(2)]], 1, R.to_domain(), ZZ)
[[1], [2]]
>>> dmp_convert([[ZZ(1)], [ZZ(2)]], 1, ZZ, R.to_domain())
[[1], [2]]
"""
if not u:
return dup_convert(f, K0, K1)
if K0 is not None and K0 == K1:
return f
v = u - 1
return dmp_strip([ dmp_convert(c, v, K0, K1) for c in f ], u)
def dup_from_sympy(f, K):
"""
Convert the ground domain of ``f`` from SymPy to ``K``.
Examples
========
>>> from sympy import S
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dup_from_sympy
>>> dup_from_sympy([S(1), S(2)], ZZ) == [ZZ(1), ZZ(2)]
True
"""
return dup_strip([ K.from_sympy(c) for c in f ])
def dmp_from_sympy(f, u, K):
"""
Convert the ground domain of ``f`` from SymPy to ``K``.
Examples
========
>>> from sympy import S
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_from_sympy
>>> dmp_from_sympy([[S(1)], [S(2)]], 1, ZZ) == [[ZZ(1)], [ZZ(2)]]
True
"""
if not u:
return dup_from_sympy(f, K)
v = u - 1
return dmp_strip([ dmp_from_sympy(c, v, K) for c in f ], u)
def dup_nth(f, n, K):
"""
Return the ``n``-th coefficient of ``f`` in ``K[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dup_nth
>>> f = ZZ.map([1, 2, 3])
>>> dup_nth(f, 0, ZZ)
3
>>> dup_nth(f, 4, ZZ)
0
"""
if n < 0:
raise IndexError("'n' must be non-negative, got %i" % n)
elif n >= len(f):
return K.zero
else:
return f[dup_degree(f) - n]
def dmp_nth(f, n, u, K):
"""
Return the ``n``-th coefficient of ``f`` in ``K[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_nth
>>> f = ZZ.map([[1], [2], [3]])
>>> dmp_nth(f, 0, 1, ZZ)
[3]
>>> dmp_nth(f, 4, 1, ZZ)
[]
"""
if n < 0:
raise IndexError("'n' must be non-negative, got %i" % n)
elif n >= len(f):
return dmp_zero(u - 1)
else:
return f[dmp_degree(f, u) - n]
def dmp_ground_nth(f, N, u, K):
"""
Return the ground ``n``-th coefficient of ``f`` in ``K[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_ground_nth
>>> f = ZZ.map([[1], [2, 3]])
>>> dmp_ground_nth(f, (0, 1), 1, ZZ)
2
"""
v = u
for n in N:
if n < 0:
raise IndexError("`n` must be non-negative, got %i" % n)
elif n >= len(f):
return K.zero
else:
d = dmp_degree(f, v)
if d == ninf:
d = -1
f, v = f[d - n], v - 1
return f
def dmp_zero_p(f, u):
"""
Return ``True`` if ``f`` is zero in ``K[X]``.
Examples
========
>>> from sympy.polys.densebasic import dmp_zero_p
>>> dmp_zero_p([[[[[]]]]], 4)
True
>>> dmp_zero_p([[[[[1]]]]], 4)
False
"""
while u:
if len(f) != 1:
return False
f = f[0]
u -= 1
return not f
def dmp_zero(u):
"""
Return a multivariate zero.
Examples
========
>>> from sympy.polys.densebasic import dmp_zero
>>> dmp_zero(4)
[[[[[]]]]]
"""
r = []
for i in range(u):
r = [r]
return r
def dmp_one_p(f, u, K):
"""
Return ``True`` if ``f`` is one in ``K[X]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_one_p
>>> dmp_one_p([[[ZZ(1)]]], 2, ZZ)
True
"""
return dmp_ground_p(f, K.one, u)
def dmp_one(u, K):
"""
Return a multivariate one over ``K``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_one
>>> dmp_one(2, ZZ)
[[[1]]]
"""
return dmp_ground(K.one, u)
def dmp_ground_p(f, c, u):
"""
Return True if ``f`` is constant in ``K[X]``.
Examples
========
>>> from sympy.polys.densebasic import dmp_ground_p
>>> dmp_ground_p([[[3]]], 3, 2)
True
>>> dmp_ground_p([[[4]]], None, 2)
True
"""
if c is not None and not c:
return dmp_zero_p(f, u)
while u:
if len(f) != 1:
return False
f = f[0]
u -= 1
if c is None:
return len(f) <= 1
else:
return f == [c]
def dmp_ground(c, u):
"""
Return a multivariate constant.
Examples
========
>>> from sympy.polys.densebasic import dmp_ground
>>> dmp_ground(3, 5)
[[[[[[3]]]]]]
>>> dmp_ground(1, -1)
1
"""
if not c:
return dmp_zero(u)
for i in range(u + 1):
c = [c]
return c
def dmp_zeros(n, u, K):
"""
Return a list of multivariate zeros.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_zeros
>>> dmp_zeros(3, 2, ZZ)
[[[[]]], [[[]]], [[[]]]]
>>> dmp_zeros(3, -1, ZZ)
[0, 0, 0]
"""
if not n:
return []
if u < 0:
return [K.zero]*n
else:
return [ dmp_zero(u) for i in range(n) ]
def dmp_grounds(c, n, u):
"""
Return a list of multivariate constants.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_grounds
>>> dmp_grounds(ZZ(4), 3, 2)
[[[[4]]], [[[4]]], [[[4]]]]
>>> dmp_grounds(ZZ(4), 3, -1)
[4, 4, 4]
"""
if not n:
return []
if u < 0:
return [c]*n
else:
return [ dmp_ground(c, u) for i in range(n) ]
def dmp_negative_p(f, u, K):
"""
Return ``True`` if ``LC(f)`` is negative.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_negative_p
>>> dmp_negative_p([[ZZ(1)], [-ZZ(1)]], 1, ZZ)
False
>>> dmp_negative_p([[-ZZ(1)], [ZZ(1)]], 1, ZZ)
True
"""
return K.is_negative(dmp_ground_LC(f, u, K))
def dmp_positive_p(f, u, K):
"""
Return ``True`` if ``LC(f)`` is positive.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_positive_p
>>> dmp_positive_p([[ZZ(1)], [-ZZ(1)]], 1, ZZ)
True
>>> dmp_positive_p([[-ZZ(1)], [ZZ(1)]], 1, ZZ)
False
"""
return K.is_positive(dmp_ground_LC(f, u, K))
def dup_from_dict(f, K):
"""
Create a ``K[x]`` polynomial from a ``dict``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dup_from_dict
>>> dup_from_dict({(0,): ZZ(7), (2,): ZZ(5), (4,): ZZ(1)}, ZZ)
[1, 0, 5, 0, 7]
>>> dup_from_dict({}, ZZ)
[]
"""
if not f:
return []
n, h = max(f.keys()), []
if isinstance(n, int):
for k in range(n, -1, -1):
h.append(f.get(k, K.zero))
else:
(n,) = n
for k in range(n, -1, -1):
h.append(f.get((k,), K.zero))
return dup_strip(h)
def dup_from_raw_dict(f, K):
"""
Create a ``K[x]`` polynomial from a raw ``dict``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dup_from_raw_dict
>>> dup_from_raw_dict({0: ZZ(7), 2: ZZ(5), 4: ZZ(1)}, ZZ)
[1, 0, 5, 0, 7]
"""
if not f:
return []
n, h = max(f.keys()), []
for k in range(n, -1, -1):
h.append(f.get(k, K.zero))
return dup_strip(h)
def dmp_from_dict(f, u, K):
"""
Create a ``K[X]`` polynomial from a ``dict``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_from_dict
>>> dmp_from_dict({(0, 0): ZZ(3), (0, 1): ZZ(2), (2, 1): ZZ(1)}, 1, ZZ)
[[1, 0], [], [2, 3]]
>>> dmp_from_dict({}, 0, ZZ)
[]
"""
if not u:
return dup_from_dict(f, K)
if not f:
return dmp_zero(u)
coeffs = {}
for monom, coeff in f.items():
head, tail = monom[0], monom[1:]
if head in coeffs:
coeffs[head][tail] = coeff
else:
coeffs[head] = { tail: coeff }
n, v, h = max(coeffs.keys()), u - 1, []
for k in range(n, -1, -1):
coeff = coeffs.get(k)
if coeff is not None:
h.append(dmp_from_dict(coeff, v, K))
else:
h.append(dmp_zero(v))
return dmp_strip(h, u)
def dup_to_dict(f, K=None, zero=False):
"""
Convert ``K[x]`` polynomial to a ``dict``.
Examples
========
>>> from sympy.polys.densebasic import dup_to_dict
>>> dup_to_dict([1, 0, 5, 0, 7])
{(0,): 7, (2,): 5, (4,): 1}
>>> dup_to_dict([])
{}
"""
if not f and zero:
return {(0,): K.zero}
n, result = len(f) - 1, {}
for k in range(0, n + 1):
if f[n - k]:
result[(k,)] = f[n - k]
return result
def dup_to_raw_dict(f, K=None, zero=False):
"""
Convert a ``K[x]`` polynomial to a raw ``dict``.
Examples
========
>>> from sympy.polys.densebasic import dup_to_raw_dict
>>> dup_to_raw_dict([1, 0, 5, 0, 7])
{0: 7, 2: 5, 4: 1}
"""
if not f and zero:
return {0: K.zero}
n, result = len(f) - 1, {}
for k in range(0, n + 1):
if f[n - k]:
result[k] = f[n - k]
return result
def dmp_to_dict(f, u, K=None, zero=False):
"""
Convert a ``K[X]`` polynomial to a ``dict````.
Examples
========
>>> from sympy.polys.densebasic import dmp_to_dict
>>> dmp_to_dict([[1, 0], [], [2, 3]], 1)
{(0, 0): 3, (0, 1): 2, (2, 1): 1}
>>> dmp_to_dict([], 0)
{}
"""
if not u:
return dup_to_dict(f, K, zero=zero)
if dmp_zero_p(f, u) and zero:
return {(0,)*(u + 1): K.zero}
n, v, result = dmp_degree(f, u), u - 1, {}
if n == ninf:
n = -1
for k in range(0, n + 1):
h = dmp_to_dict(f[n - k], v)
for exp, coeff in h.items():
result[(k,) + exp] = coeff
return result
def dmp_swap(f, i, j, u, K):
"""
Transform ``K[..x_i..x_j..]`` to ``K[..x_j..x_i..]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_swap
>>> f = ZZ.map([[[2], [1, 0]], []])
>>> dmp_swap(f, 0, 1, 2, ZZ)
[[[2], []], [[1, 0], []]]
>>> dmp_swap(f, 1, 2, 2, ZZ)
[[[1], [2, 0]], [[]]]
>>> dmp_swap(f, 0, 2, 2, ZZ)
[[[1, 0]], [[2, 0], []]]
"""
if i < 0 or j < 0 or i > u or j > u:
raise IndexError("0 <= i < j <= %s expected" % u)
elif i == j:
return f
F, H = dmp_to_dict(f, u), {}
for exp, coeff in F.items():
H[exp[:i] + (exp[j],) +
exp[i + 1:j] +
(exp[i],) + exp[j + 1:]] = coeff
return dmp_from_dict(H, u, K)
def dmp_permute(f, P, u, K):
"""
Return a polynomial in ``K[x_{P(1)},..,x_{P(n)}]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_permute
>>> f = ZZ.map([[[2], [1, 0]], []])
>>> dmp_permute(f, [1, 0, 2], 2, ZZ)
[[[2], []], [[1, 0], []]]
>>> dmp_permute(f, [1, 2, 0], 2, ZZ)
[[[1], []], [[2, 0], []]]
"""
F, H = dmp_to_dict(f, u), {}
for exp, coeff in F.items():
new_exp = [0]*len(exp)
for e, p in zip(exp, P):
new_exp[p] = e
H[tuple(new_exp)] = coeff
return dmp_from_dict(H, u, K)
def dmp_nest(f, l, K):
"""
Return a multivariate value nested ``l``-levels.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_nest
>>> dmp_nest([[ZZ(1)]], 2, ZZ)
[[[[1]]]]
"""
if not isinstance(f, list):
return dmp_ground(f, l)
for i in range(l):
f = [f]
return f
def dmp_raise(f, l, u, K):
"""
Return a multivariate polynomial raised ``l``-levels.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_raise
>>> f = ZZ.map([[], [1, 2]])
>>> dmp_raise(f, 2, 1, ZZ)
[[[[]]], [[[1]], [[2]]]]
"""
if not l:
return f
if not u:
if not f:
return dmp_zero(l)
k = l - 1
return [ dmp_ground(c, k) for c in f ]
v = u - 1
return [ dmp_raise(c, l, v, K) for c in f ]
def dup_deflate(f, K):
"""
Map ``x**m`` to ``y`` in a polynomial in ``K[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dup_deflate
>>> f = ZZ.map([1, 0, 0, 1, 0, 0, 1])
>>> dup_deflate(f, ZZ)
(3, [1, 1, 1])
"""
if dup_degree(f) <= 0:
return 1, f
g = 0
for i in range(len(f)):
if not f[-i - 1]:
continue
g = igcd(g, i)
if g == 1:
return 1, f
return g, f[::g]
def dmp_deflate(f, u, K):
"""
Map ``x_i**m_i`` to ``y_i`` in a polynomial in ``K[X]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_deflate
>>> f = ZZ.map([[1, 0, 0, 2], [], [3, 0, 0, 4]])
>>> dmp_deflate(f, 1, ZZ)
((2, 3), [[1, 2], [3, 4]])
"""
if dmp_zero_p(f, u):
return (1,)*(u + 1), f
F = dmp_to_dict(f, u)
B = [0]*(u + 1)
for M in F.keys():
for i, m in enumerate(M):
B[i] = igcd(B[i], m)
for i, b in enumerate(B):
if not b:
B[i] = 1
B = tuple(B)
if all(b == 1 for b in B):
return B, f
H = {}
for A, coeff in F.items():
N = [ a // b for a, b in zip(A, B) ]
H[tuple(N)] = coeff
return B, dmp_from_dict(H, u, K)
def dup_multi_deflate(polys, K):
"""
Map ``x**m`` to ``y`` in a set of polynomials in ``K[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dup_multi_deflate
>>> f = ZZ.map([1, 0, 2, 0, 3])
>>> g = ZZ.map([4, 0, 0])
>>> dup_multi_deflate((f, g), ZZ)
(2, ([1, 2, 3], [4, 0]))
"""
G = 0
for p in polys:
if dup_degree(p) <= 0:
return 1, polys
g = 0
for i in range(len(p)):
if not p[-i - 1]:
continue
g = igcd(g, i)
if g == 1:
return 1, polys
G = igcd(G, g)
return G, tuple([ p[::G] for p in polys ])
def dmp_multi_deflate(polys, u, K):
"""
Map ``x_i**m_i`` to ``y_i`` in a set of polynomials in ``K[X]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_multi_deflate
>>> f = ZZ.map([[1, 0, 0, 2], [], [3, 0, 0, 4]])
>>> g = ZZ.map([[1, 0, 2], [], [3, 0, 4]])
>>> dmp_multi_deflate((f, g), 1, ZZ)
((2, 1), ([[1, 0, 0, 2], [3, 0, 0, 4]], [[1, 0, 2], [3, 0, 4]]))
"""
if not u:
M, H = dup_multi_deflate(polys, K)
return (M,), H
F, B = [], [0]*(u + 1)
for p in polys:
f = dmp_to_dict(p, u)
if not dmp_zero_p(p, u):
for M in f.keys():
for i, m in enumerate(M):
B[i] = igcd(B[i], m)
F.append(f)
for i, b in enumerate(B):
if not b:
B[i] = 1
B = tuple(B)
if all(b == 1 for b in B):
return B, polys
H = []
for f in F:
h = {}
for A, coeff in f.items():
N = [ a // b for a, b in zip(A, B) ]
h[tuple(N)] = coeff
H.append(dmp_from_dict(h, u, K))
return B, tuple(H)
def dup_inflate(f, m, K):
"""
Map ``y`` to ``x**m`` in a polynomial in ``K[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dup_inflate
>>> f = ZZ.map([1, 1, 1])
>>> dup_inflate(f, 3, ZZ)
[1, 0, 0, 1, 0, 0, 1]
"""
if m <= 0:
raise IndexError("'m' must be positive, got %s" % m)
if m == 1 or not f:
return f
result = [f[0]]
for coeff in f[1:]:
result.extend([K.zero]*(m - 1))
result.append(coeff)
return result
def _rec_inflate(g, M, v, i, K):
"""Recursive helper for :func:`dmp_inflate`."""
if not v:
return dup_inflate(g, M[i], K)
if M[i] <= 0:
raise IndexError("all M[i] must be positive, got %s" % M[i])
w, j = v - 1, i + 1
g = [ _rec_inflate(c, M, w, j, K) for c in g ]
result = [g[0]]
for coeff in g[1:]:
for _ in range(1, M[i]):
result.append(dmp_zero(w))
result.append(coeff)
return result
def dmp_inflate(f, M, u, K):
"""
Map ``y_i`` to ``x_i**k_i`` in a polynomial in ``K[X]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_inflate
>>> f = ZZ.map([[1, 2], [3, 4]])
>>> dmp_inflate(f, (2, 3), 1, ZZ)
[[1, 0, 0, 2], [], [3, 0, 0, 4]]
"""
if not u:
return dup_inflate(f, M[0], K)
if all(m == 1 for m in M):
return f
else:
return _rec_inflate(f, M, u, 0, K)
def dmp_exclude(f, u, K):
"""
Exclude useless levels from ``f``.
Return the levels excluded, the new excluded ``f``, and the new ``u``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_exclude
>>> f = ZZ.map([[[1]], [[1], [2]]])
>>> dmp_exclude(f, 2, ZZ)
([2], [[1], [1, 2]], 1)
"""
if not u or dmp_ground_p(f, None, u):
return [], f, u
J, F = [], dmp_to_dict(f, u)
for j in range(0, u + 1):
for monom in F.keys():
if monom[j]:
break
else:
J.append(j)
if not J:
return [], f, u
f = {}
for monom, coeff in F.items():
monom = list(monom)
for j in reversed(J):
del monom[j]
f[tuple(monom)] = coeff
u -= len(J)
return J, dmp_from_dict(f, u, K), u
def dmp_include(f, J, u, K):
"""
Include useless levels in ``f``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_include
>>> f = ZZ.map([[1], [1, 2]])
>>> dmp_include(f, [2], 1, ZZ)
[[[1]], [[1], [2]]]
"""
if not J:
return f
F, f = dmp_to_dict(f, u), {}
for monom, coeff in F.items():
monom = list(monom)
for j in J:
monom.insert(j, 0)
f[tuple(monom)] = coeff
u += len(J)
return dmp_from_dict(f, u, K)
def dmp_inject(f, u, K, front=False):
"""
Convert ``f`` from ``K[X][Y]`` to ``K[X,Y]``.
Examples
========
>>> from sympy.polys.rings import ring
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_inject
>>> R, x,y = ring("x,y", ZZ)
>>> dmp_inject([R(1), x + 2], 0, R.to_domain())
([[[1]], [[1], [2]]], 2)
>>> dmp_inject([R(1), x + 2], 0, R.to_domain(), front=True)
([[[1]], [[1, 2]]], 2)
"""
f, h = dmp_to_dict(f, u), {}
v = K.ngens - 1
for f_monom, g in f.items():
g = g.to_dict()
for g_monom, c in g.items():
if front:
h[g_monom + f_monom] = c
else:
h[f_monom + g_monom] = c
w = u + v + 1
return dmp_from_dict(h, w, K.dom), w
def dmp_eject(f, u, K, front=False):
"""
Convert ``f`` from ``K[X,Y]`` to ``K[X][Y]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_eject
>>> dmp_eject([[[1]], [[1], [2]]], 2, ZZ['x', 'y'])
[1, x + 2]
"""
f, h = dmp_to_dict(f, u), {}
n = K.ngens
v = u - K.ngens + 1
for monom, c in f.items():
if front:
g_monom, f_monom = monom[:n], monom[n:]
else:
g_monom, f_monom = monom[-n:], monom[:-n]
if f_monom in h:
h[f_monom][g_monom] = c
else:
h[f_monom] = {g_monom: c}
for monom, c in h.items():
h[monom] = K(c)
return dmp_from_dict(h, v - 1, K)
def dup_terms_gcd(f, K):
"""
Remove GCD of terms from ``f`` in ``K[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dup_terms_gcd
>>> f = ZZ.map([1, 0, 1, 0, 0])
>>> dup_terms_gcd(f, ZZ)
(2, [1, 0, 1])
"""
if dup_TC(f, K) or not f:
return 0, f
i = 0
for c in reversed(f):
if not c:
i += 1
else:
break
return i, f[:-i]
def dmp_terms_gcd(f, u, K):
"""
Remove GCD of terms from ``f`` in ``K[X]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_terms_gcd
>>> f = ZZ.map([[1, 0], [1, 0, 0], [], []])
>>> dmp_terms_gcd(f, 1, ZZ)
((2, 1), [[1], [1, 0]])
"""
if dmp_ground_TC(f, u, K) or dmp_zero_p(f, u):
return (0,)*(u + 1), f
F = dmp_to_dict(f, u)
G = monomial_min(*list(F.keys()))
if all(g == 0 for g in G):
return G, f
f = {}
for monom, coeff in F.items():
f[monomial_div(monom, G)] = coeff
return G, dmp_from_dict(f, u, K)
def _rec_list_terms(g, v, monom):
"""Recursive helper for :func:`dmp_list_terms`."""
d, terms = dmp_degree(g, v), []
if not v:
for i, c in enumerate(g):
if not c:
continue
terms.append((monom + (d - i,), c))
else:
w = v - 1
for i, c in enumerate(g):
terms.extend(_rec_list_terms(c, w, monom + (d - i,)))
return terms
def dmp_list_terms(f, u, K, order=None):
"""
List all non-zero terms from ``f`` in the given order ``order``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_list_terms
>>> f = ZZ.map([[1, 1], [2, 3]])
>>> dmp_list_terms(f, 1, ZZ)
[((1, 1), 1), ((1, 0), 1), ((0, 1), 2), ((0, 0), 3)]
>>> dmp_list_terms(f, 1, ZZ, order='grevlex')
[((1, 1), 1), ((1, 0), 1), ((0, 1), 2), ((0, 0), 3)]
"""
def sort(terms, O):
return sorted(terms, key=lambda term: O(term[0]), reverse=True)
terms = _rec_list_terms(f, u, ())
if not terms:
return [((0,)*(u + 1), K.zero)]
if order is None:
return terms
else:
return sort(terms, monomial_key(order))
def dup_apply_pairs(f, g, h, args, K):
"""
Apply ``h`` to pairs of coefficients of ``f`` and ``g``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dup_apply_pairs
>>> h = lambda x, y, z: 2*x + y - z
>>> dup_apply_pairs([1, 2, 3], [3, 2, 1], h, (1,), ZZ)
[4, 5, 6]
"""
n, m = len(f), len(g)
if n != m:
if n > m:
g = [K.zero]*(n - m) + g
else:
f = [K.zero]*(m - n) + f
result = []
for a, b in zip(f, g):
result.append(h(a, b, *args))
return dup_strip(result)
def dmp_apply_pairs(f, g, h, args, u, K):
"""
Apply ``h`` to pairs of coefficients of ``f`` and ``g``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dmp_apply_pairs
>>> h = lambda x, y, z: 2*x + y - z
>>> dmp_apply_pairs([[1], [2, 3]], [[3], [2, 1]], h, (1,), 1, ZZ)
[[4], [5, 6]]
"""
if not u:
return dup_apply_pairs(f, g, h, args, K)
n, m, v = len(f), len(g), u - 1
if n != m:
if n > m:
g = dmp_zeros(n - m, v, K) + g
else:
f = dmp_zeros(m - n, v, K) + f
result = []
for a, b in zip(f, g):
result.append(dmp_apply_pairs(a, b, h, args, v, K))
return dmp_strip(result, u)
def dup_slice(f, m, n, K):
"""Take a continuous subsequence of terms of ``f`` in ``K[x]``. """
k = len(f)
if k >= m:
M = k - m
else:
M = 0
if k >= n:
N = k - n
else:
N = 0
f = f[N:M]
while f and f[0] == K.zero:
f.pop(0)
if not f:
return []
else:
return f + [K.zero]*m
def dmp_slice(f, m, n, u, K):
"""Take a continuous subsequence of terms of ``f`` in ``K[X]``. """
return dmp_slice_in(f, m, n, 0, u, K)
def dmp_slice_in(f, m, n, j, u, K):
"""Take a continuous subsequence of terms of ``f`` in ``x_j`` in ``K[X]``. """
if j < 0 or j > u:
raise IndexError("-%s <= j < %s expected, got %s" % (u, u, j))
if not u:
return dup_slice(f, m, n, K)
f, g = dmp_to_dict(f, u), {}
for monom, coeff in f.items():
k = monom[j]
if k < m or k >= n:
monom = monom[:j] + (0,) + monom[j + 1:]
if monom in g:
g[monom] += coeff
else:
g[monom] = coeff
return dmp_from_dict(g, u, K)
def dup_random(n, a, b, K):
"""
Return a polynomial of degree ``n`` with coefficients in ``[a, b]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.densebasic import dup_random
>>> dup_random(3, -10, 10, ZZ) #doctest: +SKIP
[-2, -8, 9, -4]
"""
f = [ K.convert(random.randint(a, b)) for _ in range(0, n + 1) ]
while not f[0]:
f[0] = K.convert(random.randint(a, b))
return f
PK ]ZZZ�l��j �j sympy/polys/densetools.py"""Advanced tools for dense recursive polynomials in ``K[x]`` or ``K[X]``. """
from sympy.polys.densearith import (
dup_add_term, dmp_add_term,
dup_lshift,
dup_add, dmp_add,
dup_sub, dmp_sub,
dup_mul, dmp_mul,
dup_sqr,
dup_div,
dup_rem, dmp_rem,
dmp_expand,
dup_mul_ground, dmp_mul_ground,
dup_quo_ground, dmp_quo_ground,
dup_exquo_ground, dmp_exquo_ground,
)
from sympy.polys.densebasic import (
dup_strip, dmp_strip,
dup_convert, dmp_convert,
dup_degree, dmp_degree,
dmp_to_dict,
dmp_from_dict,
dup_LC, dmp_LC, dmp_ground_LC,
dup_TC, dmp_TC,
dmp_zero, dmp_ground,
dmp_zero_p,
dup_to_raw_dict, dup_from_raw_dict,
dmp_zeros
)
from sympy.polys.polyerrors import (
MultivariatePolynomialError,
DomainError
)
from sympy.utilities import variations
from math import ceil as _ceil, log2 as _log2
def dup_integrate(f, m, K):
"""
Computes the indefinite integral of ``f`` in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, QQ
>>> R, x = ring("x", QQ)
>>> R.dup_integrate(x**2 + 2*x, 1)
1/3*x**3 + x**2
>>> R.dup_integrate(x**2 + 2*x, 2)
1/12*x**4 + 1/3*x**3
"""
if m <= 0 or not f:
return f
g = [K.zero]*m
for i, c in enumerate(reversed(f)):
n = i + 1
for j in range(1, m):
n *= i + j + 1
g.insert(0, K.exquo(c, K(n)))
return g
def dmp_integrate(f, m, u, K):
"""
Computes the indefinite integral of ``f`` in ``x_0`` in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, QQ
>>> R, x,y = ring("x,y", QQ)
>>> R.dmp_integrate(x + 2*y, 1)
1/2*x**2 + 2*x*y
>>> R.dmp_integrate(x + 2*y, 2)
1/6*x**3 + x**2*y
"""
if not u:
return dup_integrate(f, m, K)
if m <= 0 or dmp_zero_p(f, u):
return f
g, v = dmp_zeros(m, u - 1, K), u - 1
for i, c in enumerate(reversed(f)):
n = i + 1
for j in range(1, m):
n *= i + j + 1
g.insert(0, dmp_quo_ground(c, K(n), v, K))
return g
def _rec_integrate_in(g, m, v, i, j, K):
"""Recursive helper for :func:`dmp_integrate_in`."""
if i == j:
return dmp_integrate(g, m, v, K)
w, i = v - 1, i + 1
return dmp_strip([ _rec_integrate_in(c, m, w, i, j, K) for c in g ], v)
def dmp_integrate_in(f, m, j, u, K):
"""
Computes the indefinite integral of ``f`` in ``x_j`` in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, QQ
>>> R, x,y = ring("x,y", QQ)
>>> R.dmp_integrate_in(x + 2*y, 1, 0)
1/2*x**2 + 2*x*y
>>> R.dmp_integrate_in(x + 2*y, 1, 1)
x*y + y**2
"""
if j < 0 or j > u:
raise IndexError("0 <= j <= u expected, got u = %d, j = %d" % (u, j))
return _rec_integrate_in(f, m, u, 0, j, K)
def dup_diff(f, m, K):
"""
``m``-th order derivative of a polynomial in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_diff(x**3 + 2*x**2 + 3*x + 4, 1)
3*x**2 + 4*x + 3
>>> R.dup_diff(x**3 + 2*x**2 + 3*x + 4, 2)
6*x + 4
"""
if m <= 0:
return f
n = dup_degree(f)
if n < m:
return []
deriv = []
if m == 1:
for coeff in f[:-m]:
deriv.append(K(n)*coeff)
n -= 1
else:
for coeff in f[:-m]:
k = n
for i in range(n - 1, n - m, -1):
k *= i
deriv.append(K(k)*coeff)
n -= 1
return dup_strip(deriv)
def dmp_diff(f, m, u, K):
"""
``m``-th order derivative in ``x_0`` of a polynomial in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> f = x*y**2 + 2*x*y + 3*x + 2*y**2 + 3*y + 1
>>> R.dmp_diff(f, 1)
y**2 + 2*y + 3
>>> R.dmp_diff(f, 2)
0
"""
if not u:
return dup_diff(f, m, K)
if m <= 0:
return f
n = dmp_degree(f, u)
if n < m:
return dmp_zero(u)
deriv, v = [], u - 1
if m == 1:
for coeff in f[:-m]:
deriv.append(dmp_mul_ground(coeff, K(n), v, K))
n -= 1
else:
for coeff in f[:-m]:
k = n
for i in range(n - 1, n - m, -1):
k *= i
deriv.append(dmp_mul_ground(coeff, K(k), v, K))
n -= 1
return dmp_strip(deriv, u)
def _rec_diff_in(g, m, v, i, j, K):
"""Recursive helper for :func:`dmp_diff_in`."""
if i == j:
return dmp_diff(g, m, v, K)
w, i = v - 1, i + 1
return dmp_strip([ _rec_diff_in(c, m, w, i, j, K) for c in g ], v)
def dmp_diff_in(f, m, j, u, K):
"""
``m``-th order derivative in ``x_j`` of a polynomial in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> f = x*y**2 + 2*x*y + 3*x + 2*y**2 + 3*y + 1
>>> R.dmp_diff_in(f, 1, 0)
y**2 + 2*y + 3
>>> R.dmp_diff_in(f, 1, 1)
2*x*y + 2*x + 4*y + 3
"""
if j < 0 or j > u:
raise IndexError("0 <= j <= %s expected, got %s" % (u, j))
return _rec_diff_in(f, m, u, 0, j, K)
def dup_eval(f, a, K):
"""
Evaluate a polynomial at ``x = a`` in ``K[x]`` using Horner scheme.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_eval(x**2 + 2*x + 3, 2)
11
"""
if not a:
return K.convert(dup_TC(f, K))
result = K.zero
for c in f:
result *= a
result += c
return result
def dmp_eval(f, a, u, K):
"""
Evaluate a polynomial at ``x_0 = a`` in ``K[X]`` using the Horner scheme.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dmp_eval(2*x*y + 3*x + y + 2, 2)
5*y + 8
"""
if not u:
return dup_eval(f, a, K)
if not a:
return dmp_TC(f, K)
result, v = dmp_LC(f, K), u - 1
for coeff in f[1:]:
result = dmp_mul_ground(result, a, v, K)
result = dmp_add(result, coeff, v, K)
return result
def _rec_eval_in(g, a, v, i, j, K):
"""Recursive helper for :func:`dmp_eval_in`."""
if i == j:
return dmp_eval(g, a, v, K)
v, i = v - 1, i + 1
return dmp_strip([ _rec_eval_in(c, a, v, i, j, K) for c in g ], v)
def dmp_eval_in(f, a, j, u, K):
"""
Evaluate a polynomial at ``x_j = a`` in ``K[X]`` using the Horner scheme.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> f = 2*x*y + 3*x + y + 2
>>> R.dmp_eval_in(f, 2, 0)
5*y + 8
>>> R.dmp_eval_in(f, 2, 1)
7*x + 4
"""
if j < 0 or j > u:
raise IndexError("0 <= j <= %s expected, got %s" % (u, j))
return _rec_eval_in(f, a, u, 0, j, K)
def _rec_eval_tail(g, i, A, u, K):
"""Recursive helper for :func:`dmp_eval_tail`."""
if i == u:
return dup_eval(g, A[-1], K)
else:
h = [ _rec_eval_tail(c, i + 1, A, u, K) for c in g ]
if i < u - len(A) + 1:
return h
else:
return dup_eval(h, A[-u + i - 1], K)
def dmp_eval_tail(f, A, u, K):
"""
Evaluate a polynomial at ``x_j = a_j, ...`` in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> f = 2*x*y + 3*x + y + 2
>>> R.dmp_eval_tail(f, [2])
7*x + 4
>>> R.dmp_eval_tail(f, [2, 2])
18
"""
if not A:
return f
if dmp_zero_p(f, u):
return dmp_zero(u - len(A))
e = _rec_eval_tail(f, 0, A, u, K)
if u == len(A) - 1:
return e
else:
return dmp_strip(e, u - len(A))
def _rec_diff_eval(g, m, a, v, i, j, K):
"""Recursive helper for :func:`dmp_diff_eval`."""
if i == j:
return dmp_eval(dmp_diff(g, m, v, K), a, v, K)
v, i = v - 1, i + 1
return dmp_strip([ _rec_diff_eval(c, m, a, v, i, j, K) for c in g ], v)
def dmp_diff_eval_in(f, m, a, j, u, K):
"""
Differentiate and evaluate a polynomial in ``x_j`` at ``a`` in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> f = x*y**2 + 2*x*y + 3*x + 2*y**2 + 3*y + 1
>>> R.dmp_diff_eval_in(f, 1, 2, 0)
y**2 + 2*y + 3
>>> R.dmp_diff_eval_in(f, 1, 2, 1)
6*x + 11
"""
if j > u:
raise IndexError("-%s <= j < %s expected, got %s" % (u, u, j))
if not j:
return dmp_eval(dmp_diff(f, m, u, K), a, u, K)
return _rec_diff_eval(f, m, a, u, 0, j, K)
def dup_trunc(f, p, K):
"""
Reduce a ``K[x]`` polynomial modulo a constant ``p`` in ``K``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_trunc(2*x**3 + 3*x**2 + 5*x + 7, ZZ(3))
-x**3 - x + 1
"""
if K.is_ZZ:
g = []
for c in f:
c = c % p
if c > p // 2:
g.append(c - p)
else:
g.append(c)
elif K.is_FiniteField:
# XXX: python-flint's nmod does not support %
pi = int(p)
g = [ K(int(c) % pi) for c in f ]
else:
g = [ c % p for c in f ]
return dup_strip(g)
def dmp_trunc(f, p, u, K):
"""
Reduce a ``K[X]`` polynomial modulo a polynomial ``p`` in ``K[Y]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> f = 3*x**2*y + 8*x**2 + 5*x*y + 6*x + 2*y + 3
>>> g = (y - 1).drop(x)
>>> R.dmp_trunc(f, g)
11*x**2 + 11*x + 5
"""
return dmp_strip([ dmp_rem(c, p, u - 1, K) for c in f ], u)
def dmp_ground_trunc(f, p, u, K):
"""
Reduce a ``K[X]`` polynomial modulo a constant ``p`` in ``K``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> f = 3*x**2*y + 8*x**2 + 5*x*y + 6*x + 2*y + 3
>>> R.dmp_ground_trunc(f, ZZ(3))
-x**2 - x*y - y
"""
if not u:
return dup_trunc(f, p, K)
v = u - 1
return dmp_strip([ dmp_ground_trunc(c, p, v, K) for c in f ], u)
def dup_monic(f, K):
"""
Divide all coefficients by ``LC(f)`` in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ, QQ
>>> R, x = ring("x", ZZ)
>>> R.dup_monic(3*x**2 + 6*x + 9)
x**2 + 2*x + 3
>>> R, x = ring("x", QQ)
>>> R.dup_monic(3*x**2 + 4*x + 2)
x**2 + 4/3*x + 2/3
"""
if not f:
return f
lc = dup_LC(f, K)
if K.is_one(lc):
return f
else:
return dup_exquo_ground(f, lc, K)
def dmp_ground_monic(f, u, K):
"""
Divide all coefficients by ``LC(f)`` in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ, QQ
>>> R, x,y = ring("x,y", ZZ)
>>> f = 3*x**2*y + 6*x**2 + 3*x*y + 9*y + 3
>>> R.dmp_ground_monic(f)
x**2*y + 2*x**2 + x*y + 3*y + 1
>>> R, x,y = ring("x,y", QQ)
>>> f = 3*x**2*y + 8*x**2 + 5*x*y + 6*x + 2*y + 3
>>> R.dmp_ground_monic(f)
x**2*y + 8/3*x**2 + 5/3*x*y + 2*x + 2/3*y + 1
"""
if not u:
return dup_monic(f, K)
if dmp_zero_p(f, u):
return f
lc = dmp_ground_LC(f, u, K)
if K.is_one(lc):
return f
else:
return dmp_exquo_ground(f, lc, u, K)
def dup_content(f, K):
"""
Compute the GCD of coefficients of ``f`` in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ, QQ
>>> R, x = ring("x", ZZ)
>>> f = 6*x**2 + 8*x + 12
>>> R.dup_content(f)
2
>>> R, x = ring("x", QQ)
>>> f = 6*x**2 + 8*x + 12
>>> R.dup_content(f)
2
"""
from sympy.polys.domains import QQ
if not f:
return K.zero
cont = K.zero
if K == QQ:
for c in f:
cont = K.gcd(cont, c)
else:
for c in f:
cont = K.gcd(cont, c)
if K.is_one(cont):
break
return cont
def dmp_ground_content(f, u, K):
"""
Compute the GCD of coefficients of ``f`` in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ, QQ
>>> R, x,y = ring("x,y", ZZ)
>>> f = 2*x*y + 6*x + 4*y + 12
>>> R.dmp_ground_content(f)
2
>>> R, x,y = ring("x,y", QQ)
>>> f = 2*x*y + 6*x + 4*y + 12
>>> R.dmp_ground_content(f)
2
"""
from sympy.polys.domains import QQ
if not u:
return dup_content(f, K)
if dmp_zero_p(f, u):
return K.zero
cont, v = K.zero, u - 1
if K == QQ:
for c in f:
cont = K.gcd(cont, dmp_ground_content(c, v, K))
else:
for c in f:
cont = K.gcd(cont, dmp_ground_content(c, v, K))
if K.is_one(cont):
break
return cont
def dup_primitive(f, K):
"""
Compute content and the primitive form of ``f`` in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ, QQ
>>> R, x = ring("x", ZZ)
>>> f = 6*x**2 + 8*x + 12
>>> R.dup_primitive(f)
(2, 3*x**2 + 4*x + 6)
>>> R, x = ring("x", QQ)
>>> f = 6*x**2 + 8*x + 12
>>> R.dup_primitive(f)
(2, 3*x**2 + 4*x + 6)
"""
if not f:
return K.zero, f
cont = dup_content(f, K)
if K.is_one(cont):
return cont, f
else:
return cont, dup_quo_ground(f, cont, K)
def dmp_ground_primitive(f, u, K):
"""
Compute content and the primitive form of ``f`` in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ, QQ
>>> R, x,y = ring("x,y", ZZ)
>>> f = 2*x*y + 6*x + 4*y + 12
>>> R.dmp_ground_primitive(f)
(2, x*y + 3*x + 2*y + 6)
>>> R, x,y = ring("x,y", QQ)
>>> f = 2*x*y + 6*x + 4*y + 12
>>> R.dmp_ground_primitive(f)
(2, x*y + 3*x + 2*y + 6)
"""
if not u:
return dup_primitive(f, K)
if dmp_zero_p(f, u):
return K.zero, f
cont = dmp_ground_content(f, u, K)
if K.is_one(cont):
return cont, f
else:
return cont, dmp_quo_ground(f, cont, u, K)
def dup_extract(f, g, K):
"""
Extract common content from a pair of polynomials in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_extract(6*x**2 + 12*x + 18, 4*x**2 + 8*x + 12)
(2, 3*x**2 + 6*x + 9, 2*x**2 + 4*x + 6)
"""
fc = dup_content(f, K)
gc = dup_content(g, K)
gcd = K.gcd(fc, gc)
if not K.is_one(gcd):
f = dup_quo_ground(f, gcd, K)
g = dup_quo_ground(g, gcd, K)
return gcd, f, g
def dmp_ground_extract(f, g, u, K):
"""
Extract common content from a pair of polynomials in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dmp_ground_extract(6*x*y + 12*x + 18, 4*x*y + 8*x + 12)
(2, 3*x*y + 6*x + 9, 2*x*y + 4*x + 6)
"""
fc = dmp_ground_content(f, u, K)
gc = dmp_ground_content(g, u, K)
gcd = K.gcd(fc, gc)
if not K.is_one(gcd):
f = dmp_quo_ground(f, gcd, u, K)
g = dmp_quo_ground(g, gcd, u, K)
return gcd, f, g
def dup_real_imag(f, K):
"""
Find ``f1`` and ``f2``, such that ``f(x+I*y) = f1(x,y) + f2(x,y)*I``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dup_real_imag(x**3 + x**2 + x + 1)
(x**3 + x**2 - 3*x*y**2 + x - y**2 + 1, 3*x**2*y + 2*x*y - y**3 + y)
>>> from sympy.abc import x, y, z
>>> from sympy import I
>>> (z**3 + z**2 + z + 1).subs(z, x+I*y).expand().collect(I)
x**3 + x**2 - 3*x*y**2 + x - y**2 + I*(3*x**2*y + 2*x*y - y**3 + y) + 1
"""
if not K.is_ZZ and not K.is_QQ:
raise DomainError("computing real and imaginary parts is not supported over %s" % K)
f1 = dmp_zero(1)
f2 = dmp_zero(1)
if not f:
return f1, f2
g = [[[K.one, K.zero]], [[K.one], []]]
h = dmp_ground(f[0], 2)
for c in f[1:]:
h = dmp_mul(h, g, 2, K)
h = dmp_add_term(h, dmp_ground(c, 1), 0, 2, K)
H = dup_to_raw_dict(h)
for k, h in H.items():
m = k % 4
if not m:
f1 = dmp_add(f1, h, 1, K)
elif m == 1:
f2 = dmp_add(f2, h, 1, K)
elif m == 2:
f1 = dmp_sub(f1, h, 1, K)
else:
f2 = dmp_sub(f2, h, 1, K)
return f1, f2
def dup_mirror(f, K):
"""
Evaluate efficiently the composition ``f(-x)`` in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_mirror(x**3 + 2*x**2 - 4*x + 2)
-x**3 + 2*x**2 + 4*x + 2
"""
f = list(f)
for i in range(len(f) - 2, -1, -2):
f[i] = -f[i]
return f
def dup_scale(f, a, K):
"""
Evaluate efficiently composition ``f(a*x)`` in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_scale(x**2 - 2*x + 1, ZZ(2))
4*x**2 - 4*x + 1
"""
f, n, b = list(f), len(f) - 1, a
for i in range(n - 1, -1, -1):
f[i], b = b*f[i], b*a
return f
def dup_shift(f, a, K):
"""
Evaluate efficiently Taylor shift ``f(x + a)`` in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_shift(x**2 - 2*x + 1, ZZ(2))
x**2 + 2*x + 1
"""
f, n = list(f), len(f) - 1
for i in range(n, 0, -1):
for j in range(0, i):
f[j + 1] += a*f[j]
return f
def dmp_shift(f, a, u, K):
"""
Evaluate efficiently Taylor shift ``f(X + A)`` in ``K[X]``.
Examples
========
>>> from sympy import symbols, ring, ZZ
>>> x, y = symbols('x y')
>>> R, _, _ = ring([x, y], ZZ)
>>> p = x**2*y + 2*x*y + 3*x + 4*y + 5
>>> R.dmp_shift(R(p), [ZZ(1), ZZ(2)])
x**2*y + 2*x**2 + 4*x*y + 11*x + 7*y + 22
>>> p.subs({x: x + 1, y: y + 2}).expand()
x**2*y + 2*x**2 + 4*x*y + 11*x + 7*y + 22
"""
if not u:
return dup_shift(f, a[0], K)
if dmp_zero_p(f, u):
return f
a0, a1 = a[0], a[1:]
f = [ dmp_shift(c, a1, u-1, K) for c in f ]
n = len(f) - 1
for i in range(n, 0, -1):
for j in range(0, i):
afj = dmp_mul_ground(f[j], a0, u-1, K)
f[j + 1] = dmp_add(f[j + 1], afj, u-1, K)
return f
def dup_transform(f, p, q, K):
"""
Evaluate functional transformation ``q**n * f(p/q)`` in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_transform(x**2 - 2*x + 1, x**2 + 1, x - 1)
x**4 - 2*x**3 + 5*x**2 - 4*x + 4
"""
if not f:
return []
n = len(f) - 1
h, Q = [f[0]], [[K.one]]
for i in range(0, n):
Q.append(dup_mul(Q[-1], q, K))
for c, q in zip(f[1:], Q[1:]):
h = dup_mul(h, p, K)
q = dup_mul_ground(q, c, K)
h = dup_add(h, q, K)
return h
def dup_compose(f, g, K):
"""
Evaluate functional composition ``f(g)`` in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_compose(x**2 + x, x - 1)
x**2 - x
"""
if len(g) <= 1:
return dup_strip([dup_eval(f, dup_LC(g, K), K)])
if not f:
return []
h = [f[0]]
for c in f[1:]:
h = dup_mul(h, g, K)
h = dup_add_term(h, c, 0, K)
return h
def dmp_compose(f, g, u, K):
"""
Evaluate functional composition ``f(g)`` in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dmp_compose(x*y + 2*x + y, y)
y**2 + 3*y
"""
if not u:
return dup_compose(f, g, K)
if dmp_zero_p(f, u):
return f
h = [f[0]]
for c in f[1:]:
h = dmp_mul(h, g, u, K)
h = dmp_add_term(h, c, 0, u, K)
return h
def _dup_right_decompose(f, s, K):
"""Helper function for :func:`_dup_decompose`."""
n = len(f) - 1
lc = dup_LC(f, K)
f = dup_to_raw_dict(f)
g = { s: K.one }
r = n // s
for i in range(1, s):
coeff = K.zero
for j in range(0, i):
if not n + j - i in f:
continue
if not s - j in g:
continue
fc, gc = f[n + j - i], g[s - j]
coeff += (i - r*j)*fc*gc
g[s - i] = K.quo(coeff, i*r*lc)
return dup_from_raw_dict(g, K)
def _dup_left_decompose(f, h, K):
"""Helper function for :func:`_dup_decompose`."""
g, i = {}, 0
while f:
q, r = dup_div(f, h, K)
if dup_degree(r) > 0:
return None
else:
g[i] = dup_LC(r, K)
f, i = q, i + 1
return dup_from_raw_dict(g, K)
def _dup_decompose(f, K):
"""Helper function for :func:`dup_decompose`."""
df = len(f) - 1
for s in range(2, df):
if df % s != 0:
continue
h = _dup_right_decompose(f, s, K)
if h is not None:
g = _dup_left_decompose(f, h, K)
if g is not None:
return g, h
return None
def dup_decompose(f, K):
"""
Computes functional decomposition of ``f`` in ``K[x]``.
Given a univariate polynomial ``f`` with coefficients in a field of
characteristic zero, returns list ``[f_1, f_2, ..., f_n]``, where::
f = f_1 o f_2 o ... f_n = f_1(f_2(... f_n))
and ``f_2, ..., f_n`` are monic and homogeneous polynomials of at
least second degree.
Unlike factorization, complete functional decompositions of
polynomials are not unique, consider examples:
1. ``f o g = f(x + b) o (g - b)``
2. ``x**n o x**m = x**m o x**n``
3. ``T_n o T_m = T_m o T_n``
where ``T_n`` and ``T_m`` are Chebyshev polynomials.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_decompose(x**4 - 2*x**3 + x**2)
[x**2, x**2 - x]
References
==========
.. [1] [Kozen89]_
"""
F = []
while True:
result = _dup_decompose(f, K)
if result is not None:
f, h = result
F = [h] + F
else:
break
return [f] + F
def dmp_lift(f, u, K):
"""
Convert algebraic coefficients to integers in ``K[X]``.
Examples
========
>>> from sympy.polys import ring, QQ
>>> from sympy import I
>>> K = QQ.algebraic_field(I)
>>> R, x = ring("x", K)
>>> f = x**2 + K([QQ(1), QQ(0)])*x + K([QQ(2), QQ(0)])
>>> R.dmp_lift(f)
x**8 + 2*x**6 + 9*x**4 - 8*x**2 + 16
"""
if K.is_GaussianField:
K1 = K.as_AlgebraicField()
f = dmp_convert(f, u, K, K1)
K = K1
if not K.is_Algebraic:
raise DomainError(
'computation can be done only in an algebraic domain')
F, monoms, polys = dmp_to_dict(f, u), [], []
for monom, coeff in F.items():
if not coeff.is_ground:
monoms.append(monom)
perms = variations([-1, 1], len(monoms), repetition=True)
for perm in perms:
G = dict(F)
for sign, monom in zip(perm, monoms):
if sign == -1:
G[monom] = -G[monom]
polys.append(dmp_from_dict(G, u, K))
return dmp_convert(dmp_expand(polys, u, K), u, K, K.dom)
def dup_sign_variations(f, K):
"""
Compute the number of sign variations of ``f`` in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_sign_variations(x**4 - x**2 - x + 1)
2
"""
prev, k = K.zero, 0
for coeff in f:
if K.is_negative(coeff*prev):
k += 1
if coeff:
prev = coeff
return k
def dup_clear_denoms(f, K0, K1=None, convert=False):
"""
Clear denominators, i.e. transform ``K_0`` to ``K_1``.
Examples
========
>>> from sympy.polys import ring, QQ
>>> R, x = ring("x", QQ)
>>> f = QQ(1,2)*x + QQ(1,3)
>>> R.dup_clear_denoms(f, convert=False)
(6, 3*x + 2)
>>> R.dup_clear_denoms(f, convert=True)
(6, 3*x + 2)
"""
if K1 is None:
if K0.has_assoc_Ring:
K1 = K0.get_ring()
else:
K1 = K0
common = K1.one
for c in f:
common = K1.lcm(common, K0.denom(c))
if K1.is_one(common):
if not convert:
return common, f
else:
return common, dup_convert(f, K0, K1)
# Use quo rather than exquo to handle inexact domains by discarding the
# remainder.
f = [K0.numer(c)*K1.quo(common, K0.denom(c)) for c in f]
if not convert:
return common, dup_convert(f, K1, K0)
else:
return common, f
def _rec_clear_denoms(g, v, K0, K1):
"""Recursive helper for :func:`dmp_clear_denoms`."""
common = K1.one
if not v:
for c in g:
common = K1.lcm(common, K0.denom(c))
else:
w = v - 1
for c in g:
common = K1.lcm(common, _rec_clear_denoms(c, w, K0, K1))
return common
def dmp_clear_denoms(f, u, K0, K1=None, convert=False):
"""
Clear denominators, i.e. transform ``K_0`` to ``K_1``.
Examples
========
>>> from sympy.polys import ring, QQ
>>> R, x,y = ring("x,y", QQ)
>>> f = QQ(1,2)*x + QQ(1,3)*y + 1
>>> R.dmp_clear_denoms(f, convert=False)
(6, 3*x + 2*y + 6)
>>> R.dmp_clear_denoms(f, convert=True)
(6, 3*x + 2*y + 6)
"""
if not u:
return dup_clear_denoms(f, K0, K1, convert=convert)
if K1 is None:
if K0.has_assoc_Ring:
K1 = K0.get_ring()
else:
K1 = K0
common = _rec_clear_denoms(f, u, K0, K1)
if not K1.is_one(common):
f = dmp_mul_ground(f, common, u, K0)
if not convert:
return common, f
else:
return common, dmp_convert(f, u, K0, K1)
def dup_revert(f, n, K):
"""
Compute ``f**(-1)`` mod ``x**n`` using Newton iteration.
This function computes first ``2**n`` terms of a polynomial that
is a result of inversion of a polynomial modulo ``x**n``. This is
useful to efficiently compute series expansion of ``1/f``.
Examples
========
>>> from sympy.polys import ring, QQ
>>> R, x = ring("x", QQ)
>>> f = -QQ(1,720)*x**6 + QQ(1,24)*x**4 - QQ(1,2)*x**2 + 1
>>> R.dup_revert(f, 8)
61/720*x**6 + 5/24*x**4 + 1/2*x**2 + 1
"""
g = [K.revert(dup_TC(f, K))]
h = [K.one, K.zero, K.zero]
N = int(_ceil(_log2(n)))
for i in range(1, N + 1):
a = dup_mul_ground(g, K(2), K)
b = dup_mul(f, dup_sqr(g, K), K)
g = dup_rem(dup_sub(a, b, K), h, K)
h = dup_lshift(h, dup_degree(h), K)
return g
def dmp_revert(f, g, u, K):
"""
Compute ``f**(-1)`` mod ``x**n`` using Newton iteration.
Examples
========
>>> from sympy.polys import ring, QQ
>>> R, x,y = ring("x,y", QQ)
"""
if not u:
return dup_revert(f, g, K)
else:
raise MultivariatePolynomialError(f, g)
PK ]ZZZ� @�l l sympy/polys/dispersion.pyfrom sympy.core import S
from sympy.polys import Poly
def dispersionset(p, q=None, *gens, **args):
r"""Compute the *dispersion set* of two polynomials.
For two polynomials `f(x)` and `g(x)` with `\deg f > 0`
and `\deg g > 0` the dispersion set `\operatorname{J}(f, g)` is defined as:
.. math::
\operatorname{J}(f, g)
& := \{a \in \mathbb{N}_0 | \gcd(f(x), g(x+a)) \neq 1\} \\
& = \{a \in \mathbb{N}_0 | \deg \gcd(f(x), g(x+a)) \geq 1\}
For a single polynomial one defines `\operatorname{J}(f) := \operatorname{J}(f, f)`.
Examples
========
>>> from sympy import poly
>>> from sympy.polys.dispersion import dispersion, dispersionset
>>> from sympy.abc import x
Dispersion set and dispersion of a simple polynomial:
>>> fp = poly((x - 3)*(x + 3), x)
>>> sorted(dispersionset(fp))
[0, 6]
>>> dispersion(fp)
6
Note that the definition of the dispersion is not symmetric:
>>> fp = poly(x**4 - 3*x**2 + 1, x)
>>> gp = fp.shift(-3)
>>> sorted(dispersionset(fp, gp))
[2, 3, 4]
>>> dispersion(fp, gp)
4
>>> sorted(dispersionset(gp, fp))
[]
>>> dispersion(gp, fp)
-oo
Computing the dispersion also works over field extensions:
>>> from sympy import sqrt
>>> fp = poly(x**2 + sqrt(5)*x - 1, x, domain='QQ<sqrt(5)>')
>>> gp = poly(x**2 + (2 + sqrt(5))*x + sqrt(5), x, domain='QQ<sqrt(5)>')
>>> sorted(dispersionset(fp, gp))
[2]
>>> sorted(dispersionset(gp, fp))
[1, 4]
We can even perform the computations for polynomials
having symbolic coefficients:
>>> from sympy.abc import a
>>> fp = poly(4*x**4 + (4*a + 8)*x**3 + (a**2 + 6*a + 4)*x**2 + (a**2 + 2*a)*x, x)
>>> sorted(dispersionset(fp))
[0, 1]
See Also
========
dispersion
References
==========
.. [1] [ManWright94]_
.. [2] [Koepf98]_
.. [3] [Abramov71]_
.. [4] [Man93]_
"""
# Check for valid input
same = False if q is not None else True
if same:
q = p
p = Poly(p, *gens, **args)
q = Poly(q, *gens, **args)
if not p.is_univariate or not q.is_univariate:
raise ValueError("Polynomials need to be univariate")
# The generator
if not p.gen == q.gen:
raise ValueError("Polynomials must have the same generator")
gen = p.gen
# We define the dispersion of constant polynomials to be zero
if p.degree() < 1 or q.degree() < 1:
return {0}
# Factor p and q over the rationals
fp = p.factor_list()
fq = q.factor_list() if not same else fp
# Iterate over all pairs of factors
J = set()
for s, unused in fp[1]:
for t, unused in fq[1]:
m = s.degree()
n = t.degree()
if n != m:
continue
an = s.LC()
bn = t.LC()
if not (an - bn).is_zero:
continue
# Note that the roles of `s` and `t` below are switched
# w.r.t. the original paper. This is for consistency
# with the description in the book of W. Koepf.
anm1 = s.coeff_monomial(gen**(m-1))
bnm1 = t.coeff_monomial(gen**(n-1))
alpha = (anm1 - bnm1) / S(n*bn)
if not alpha.is_integer:
continue
if alpha < 0 or alpha in J:
continue
if n > 1 and not (s - t.shift(alpha)).is_zero:
continue
J.add(alpha)
return J
def dispersion(p, q=None, *gens, **args):
r"""Compute the *dispersion* of polynomials.
For two polynomials `f(x)` and `g(x)` with `\deg f > 0`
and `\deg g > 0` the dispersion `\operatorname{dis}(f, g)` is defined as:
.. math::
\operatorname{dis}(f, g)
& := \max\{ J(f,g) \cup \{0\} \} \\
& = \max\{ \{a \in \mathbb{N} | \gcd(f(x), g(x+a)) \neq 1\} \cup \{0\} \}
and for a single polynomial `\operatorname{dis}(f) := \operatorname{dis}(f, f)`.
Note that we make the definition `\max\{\} := -\infty`.
Examples
========
>>> from sympy import poly
>>> from sympy.polys.dispersion import dispersion, dispersionset
>>> from sympy.abc import x
Dispersion set and dispersion of a simple polynomial:
>>> fp = poly((x - 3)*(x + 3), x)
>>> sorted(dispersionset(fp))
[0, 6]
>>> dispersion(fp)
6
Note that the definition of the dispersion is not symmetric:
>>> fp = poly(x**4 - 3*x**2 + 1, x)
>>> gp = fp.shift(-3)
>>> sorted(dispersionset(fp, gp))
[2, 3, 4]
>>> dispersion(fp, gp)
4
>>> sorted(dispersionset(gp, fp))
[]
>>> dispersion(gp, fp)
-oo
The maximum of an empty set is defined to be `-\infty`
as seen in this example.
Computing the dispersion also works over field extensions:
>>> from sympy import sqrt
>>> fp = poly(x**2 + sqrt(5)*x - 1, x, domain='QQ<sqrt(5)>')
>>> gp = poly(x**2 + (2 + sqrt(5))*x + sqrt(5), x, domain='QQ<sqrt(5)>')
>>> sorted(dispersionset(fp, gp))
[2]
>>> sorted(dispersionset(gp, fp))
[1, 4]
We can even perform the computations for polynomials
having symbolic coefficients:
>>> from sympy.abc import a
>>> fp = poly(4*x**4 + (4*a + 8)*x**3 + (a**2 + 6*a + 4)*x**2 + (a**2 + 2*a)*x, x)
>>> sorted(dispersionset(fp))
[0, 1]
See Also
========
dispersionset
References
==========
.. [1] [ManWright94]_
.. [2] [Koepf98]_
.. [3] [Abramov71]_
.. [4] [Man93]_
"""
J = dispersionset(p, q, *gens, **args)
if not J:
# Definition for maximum of empty set
j = S.NegativeInfinity
else:
j = max(J)
return j
PK ]ZZZ��B�CU CU ! sympy/polys/distributedmodules.pyr"""
Sparse distributed elements of free modules over multivariate (generalized)
polynomial rings.
This code and its data structures are very much like the distributed
polynomials, except that the first "exponent" of the monomial is
a module generator index. That is, the multi-exponent ``(i, e_1, ..., e_n)``
represents the "monomial" `x_1^{e_1} \cdots x_n^{e_n} f_i` of the free module
`F` generated by `f_1, \ldots, f_r` over (a localization of) the ring
`K[x_1, \ldots, x_n]`. A module element is simply stored as a list of terms
ordered by the monomial order. Here a term is a pair of a multi-exponent and a
coefficient. In general, this coefficient should never be zero (since it can
then be omitted). The zero module element is stored as an empty list.
The main routines are ``sdm_nf_mora`` and ``sdm_groebner`` which can be used
to compute, respectively, weak normal forms and standard bases. They work with
arbitrary (not necessarily global) monomial orders.
In general, product orders have to be used to construct valid monomial orders
for modules. However, ``lex`` can be used as-is.
Note that the "level" (number of variables, i.e. parameter u+1 in
distributedpolys.py) is never needed in this code.
The main reference for this file is [SCA],
"A Singular Introduction to Commutative Algebra".
"""
from itertools import permutations
from sympy.polys.monomials import (
monomial_mul, monomial_lcm, monomial_div, monomial_deg
)
from sympy.polys.polytools import Poly
from sympy.polys.polyutils import parallel_dict_from_expr
from sympy.core.singleton import S
from sympy.core.sympify import sympify
# Additional monomial tools.
def sdm_monomial_mul(M, X):
"""
Multiply tuple ``X`` representing a monomial of `K[X]` into the tuple
``M`` representing a monomial of `F`.
Examples
========
Multiplying `xy^3` into `x f_1` yields `x^2 y^3 f_1`:
>>> from sympy.polys.distributedmodules import sdm_monomial_mul
>>> sdm_monomial_mul((1, 1, 0), (1, 3))
(1, 2, 3)
"""
return (M[0],) + monomial_mul(X, M[1:])
def sdm_monomial_deg(M):
"""
Return the total degree of ``M``.
Examples
========
For example, the total degree of `x^2 y f_5` is 3:
>>> from sympy.polys.distributedmodules import sdm_monomial_deg
>>> sdm_monomial_deg((5, 2, 1))
3
"""
return monomial_deg(M[1:])
def sdm_monomial_lcm(A, B):
r"""
Return the "least common multiple" of ``A`` and ``B``.
IF `A = M e_j` and `B = N e_j`, where `M` and `N` are polynomial monomials,
this returns `\lcm(M, N) e_j`. Note that ``A`` and ``B`` involve distinct
monomials.
Otherwise the result is undefined.
Examples
========
>>> from sympy.polys.distributedmodules import sdm_monomial_lcm
>>> sdm_monomial_lcm((1, 2, 3), (1, 0, 5))
(1, 2, 5)
"""
return (A[0],) + monomial_lcm(A[1:], B[1:])
def sdm_monomial_divides(A, B):
"""
Does there exist a (polynomial) monomial X such that XA = B?
Examples
========
Positive examples:
In the following examples, the monomial is given in terms of x, y and the
generator(s), f_1, f_2 etc. The tuple form of that monomial is used in
the call to sdm_monomial_divides.
Note: the generator appears last in the expression but first in the tuple
and other factors appear in the same order that they appear in the monomial
expression.
`A = f_1` divides `B = f_1`
>>> from sympy.polys.distributedmodules import sdm_monomial_divides
>>> sdm_monomial_divides((1, 0, 0), (1, 0, 0))
True
`A = f_1` divides `B = x^2 y f_1`
>>> sdm_monomial_divides((1, 0, 0), (1, 2, 1))
True
`A = xy f_5` divides `B = x^2 y f_5`
>>> sdm_monomial_divides((5, 1, 1), (5, 2, 1))
True
Negative examples:
`A = f_1` does not divide `B = f_2`
>>> sdm_monomial_divides((1, 0, 0), (2, 0, 0))
False
`A = x f_1` does not divide `B = f_1`
>>> sdm_monomial_divides((1, 1, 0), (1, 0, 0))
False
`A = xy^2 f_5` does not divide `B = y f_5`
>>> sdm_monomial_divides((5, 1, 2), (5, 0, 1))
False
"""
return A[0] == B[0] and all(a <= b for a, b in zip(A[1:], B[1:]))
# The actual distributed modules code.
def sdm_LC(f, K):
"""Returns the leading coefficient of ``f``. """
if not f:
return K.zero
else:
return f[0][1]
def sdm_to_dict(f):
"""Make a dictionary from a distributed polynomial. """
return dict(f)
def sdm_from_dict(d, O):
"""
Create an sdm from a dictionary.
Here ``O`` is the monomial order to use.
Examples
========
>>> from sympy.polys.distributedmodules import sdm_from_dict
>>> from sympy.polys import QQ, lex
>>> dic = {(1, 1, 0): QQ(1), (1, 0, 0): QQ(2), (0, 1, 0): QQ(0)}
>>> sdm_from_dict(dic, lex)
[((1, 1, 0), 1), ((1, 0, 0), 2)]
"""
return sdm_strip(sdm_sort(list(d.items()), O))
def sdm_sort(f, O):
"""Sort terms in ``f`` using the given monomial order ``O``. """
return sorted(f, key=lambda term: O(term[0]), reverse=True)
def sdm_strip(f):
"""Remove terms with zero coefficients from ``f`` in ``K[X]``. """
return [ (monom, coeff) for monom, coeff in f if coeff ]
def sdm_add(f, g, O, K):
"""
Add two module elements ``f``, ``g``.
Addition is done over the ground field ``K``, monomials are ordered
according to ``O``.
Examples
========
All examples use lexicographic order.
`(xy f_1) + (f_2) = f_2 + xy f_1`
>>> from sympy.polys.distributedmodules import sdm_add
>>> from sympy.polys import lex, QQ
>>> sdm_add([((1, 1, 1), QQ(1))], [((2, 0, 0), QQ(1))], lex, QQ)
[((2, 0, 0), 1), ((1, 1, 1), 1)]
`(xy f_1) + (-xy f_1)` = 0`
>>> sdm_add([((1, 1, 1), QQ(1))], [((1, 1, 1), QQ(-1))], lex, QQ)
[]
`(f_1) + (2f_1) = 3f_1`
>>> sdm_add([((1, 0, 0), QQ(1))], [((1, 0, 0), QQ(2))], lex, QQ)
[((1, 0, 0), 3)]
`(yf_1) + (xf_1) = xf_1 + yf_1`
>>> sdm_add([((1, 0, 1), QQ(1))], [((1, 1, 0), QQ(1))], lex, QQ)
[((1, 1, 0), 1), ((1, 0, 1), 1)]
"""
h = dict(f)
for monom, c in g:
if monom in h:
coeff = h[monom] + c
if not coeff:
del h[monom]
else:
h[monom] = coeff
else:
h[monom] = c
return sdm_from_dict(h, O)
def sdm_LM(f):
r"""
Returns the leading monomial of ``f``.
Only valid if `f \ne 0`.
Examples
========
>>> from sympy.polys.distributedmodules import sdm_LM, sdm_from_dict
>>> from sympy.polys import QQ, lex
>>> dic = {(1, 2, 3): QQ(1), (4, 0, 0): QQ(1), (4, 0, 1): QQ(1)}
>>> sdm_LM(sdm_from_dict(dic, lex))
(4, 0, 1)
"""
return f[0][0]
def sdm_LT(f):
r"""
Returns the leading term of ``f``.
Only valid if `f \ne 0`.
Examples
========
>>> from sympy.polys.distributedmodules import sdm_LT, sdm_from_dict
>>> from sympy.polys import QQ, lex
>>> dic = {(1, 2, 3): QQ(1), (4, 0, 0): QQ(2), (4, 0, 1): QQ(3)}
>>> sdm_LT(sdm_from_dict(dic, lex))
((4, 0, 1), 3)
"""
return f[0]
def sdm_mul_term(f, term, O, K):
"""
Multiply a distributed module element ``f`` by a (polynomial) term ``term``.
Multiplication of coefficients is done over the ground field ``K``, and
monomials are ordered according to ``O``.
Examples
========
`0 f_1 = 0`
>>> from sympy.polys.distributedmodules import sdm_mul_term
>>> from sympy.polys import lex, QQ
>>> sdm_mul_term([((1, 0, 0), QQ(1))], ((0, 0), QQ(0)), lex, QQ)
[]
`x 0 = 0`
>>> sdm_mul_term([], ((1, 0), QQ(1)), lex, QQ)
[]
`(x) (f_1) = xf_1`
>>> sdm_mul_term([((1, 0, 0), QQ(1))], ((1, 0), QQ(1)), lex, QQ)
[((1, 1, 0), 1)]
`(2xy) (3x f_1 + 4y f_2) = 8xy^2 f_2 + 6x^2y f_1`
>>> f = [((2, 0, 1), QQ(4)), ((1, 1, 0), QQ(3))]
>>> sdm_mul_term(f, ((1, 1), QQ(2)), lex, QQ)
[((2, 1, 2), 8), ((1, 2, 1), 6)]
"""
X, c = term
if not f or not c:
return []
else:
if K.is_one(c):
return [ (sdm_monomial_mul(f_M, X), f_c) for f_M, f_c in f ]
else:
return [ (sdm_monomial_mul(f_M, X), f_c * c) for f_M, f_c in f ]
def sdm_zero():
"""Return the zero module element."""
return []
def sdm_deg(f):
"""
Degree of ``f``.
This is the maximum of the degrees of all its monomials.
Invalid if ``f`` is zero.
Examples
========
>>> from sympy.polys.distributedmodules import sdm_deg
>>> sdm_deg([((1, 2, 3), 1), ((10, 0, 1), 1), ((2, 3, 4), 4)])
7
"""
return max(sdm_monomial_deg(M[0]) for M in f)
# Conversion
def sdm_from_vector(vec, O, K, **opts):
"""
Create an sdm from an iterable of expressions.
Coefficients are created in the ground field ``K``, and terms are ordered
according to monomial order ``O``. Named arguments are passed on to the
polys conversion code and can be used to specify for example generators.
Examples
========
>>> from sympy.polys.distributedmodules import sdm_from_vector
>>> from sympy.abc import x, y, z
>>> from sympy.polys import QQ, lex
>>> sdm_from_vector([x**2+y**2, 2*z], lex, QQ)
[((1, 0, 0, 1), 2), ((0, 2, 0, 0), 1), ((0, 0, 2, 0), 1)]
"""
dics, gens = parallel_dict_from_expr(sympify(vec), **opts)
dic = {}
for i, d in enumerate(dics):
for k, v in d.items():
dic[(i,) + k] = K.convert(v)
return sdm_from_dict(dic, O)
def sdm_to_vector(f, gens, K, n=None):
"""
Convert sdm ``f`` into a list of polynomial expressions.
The generators for the polynomial ring are specified via ``gens``. The rank
of the module is guessed, or passed via ``n``. The ground field is assumed
to be ``K``.
Examples
========
>>> from sympy.polys.distributedmodules import sdm_to_vector
>>> from sympy.abc import x, y, z
>>> from sympy.polys import QQ
>>> f = [((1, 0, 0, 1), QQ(2)), ((0, 2, 0, 0), QQ(1)), ((0, 0, 2, 0), QQ(1))]
>>> sdm_to_vector(f, [x, y, z], QQ)
[x**2 + y**2, 2*z]
"""
dic = sdm_to_dict(f)
dics = {}
for k, v in dic.items():
dics.setdefault(k[0], []).append((k[1:], v))
n = n or len(dics)
res = []
for k in range(n):
if k in dics:
res.append(Poly(dict(dics[k]), gens=gens, domain=K).as_expr())
else:
res.append(S.Zero)
return res
# Algorithms.
def sdm_spoly(f, g, O, K, phantom=None):
"""
Compute the generalized s-polynomial of ``f`` and ``g``.
The ground field is assumed to be ``K``, and monomials ordered according to
``O``.
This is invalid if either of ``f`` or ``g`` is zero.
If the leading terms of `f` and `g` involve different basis elements of
`F`, their s-poly is defined to be zero. Otherwise it is a certain linear
combination of `f` and `g` in which the leading terms cancel.
See [SCA, defn 2.3.6] for details.
If ``phantom`` is not ``None``, it should be a pair of module elements on
which to perform the same operation(s) as on ``f`` and ``g``. The in this
case both results are returned.
Examples
========
>>> from sympy.polys.distributedmodules import sdm_spoly
>>> from sympy.polys import QQ, lex
>>> f = [((2, 1, 1), QQ(1)), ((1, 0, 1), QQ(1))]
>>> g = [((2, 3, 0), QQ(1))]
>>> h = [((1, 2, 3), QQ(1))]
>>> sdm_spoly(f, h, lex, QQ)
[]
>>> sdm_spoly(f, g, lex, QQ)
[((1, 2, 1), 1)]
"""
if not f or not g:
return sdm_zero()
LM1 = sdm_LM(f)
LM2 = sdm_LM(g)
if LM1[0] != LM2[0]:
return sdm_zero()
LM1 = LM1[1:]
LM2 = LM2[1:]
lcm = monomial_lcm(LM1, LM2)
m1 = monomial_div(lcm, LM1)
m2 = monomial_div(lcm, LM2)
c = K.quo(-sdm_LC(f, K), sdm_LC(g, K))
r1 = sdm_add(sdm_mul_term(f, (m1, K.one), O, K),
sdm_mul_term(g, (m2, c), O, K), O, K)
if phantom is None:
return r1
r2 = sdm_add(sdm_mul_term(phantom[0], (m1, K.one), O, K),
sdm_mul_term(phantom[1], (m2, c), O, K), O, K)
return r1, r2
def sdm_ecart(f):
"""
Compute the ecart of ``f``.
This is defined to be the difference of the total degree of `f` and the
total degree of the leading monomial of `f` [SCA, defn 2.3.7].
Invalid if f is zero.
Examples
========
>>> from sympy.polys.distributedmodules import sdm_ecart
>>> sdm_ecart([((1, 2, 3), 1), ((1, 0, 1), 1)])
0
>>> sdm_ecart([((2, 2, 1), 1), ((1, 5, 1), 1)])
3
"""
return sdm_deg(f) - sdm_monomial_deg(sdm_LM(f))
def sdm_nf_mora(f, G, O, K, phantom=None):
r"""
Compute a weak normal form of ``f`` with respect to ``G`` and order ``O``.
The ground field is assumed to be ``K``, and monomials ordered according to
``O``.
Weak normal forms are defined in [SCA, defn 2.3.3]. They are not unique.
This function deterministically computes a weak normal form, depending on
the order of `G`.
The most important property of a weak normal form is the following: if
`R` is the ring associated with the monomial ordering (if the ordering is
global, we just have `R = K[x_1, \ldots, x_n]`, otherwise it is a certain
localization thereof), `I` any ideal of `R` and `G` a standard basis for
`I`, then for any `f \in R`, we have `f \in I` if and only if
`NF(f | G) = 0`.
This is the generalized Mora algorithm for computing weak normal forms with
respect to arbitrary monomial orders [SCA, algorithm 2.3.9].
If ``phantom`` is not ``None``, it should be a pair of "phantom" arguments
on which to perform the same computations as on ``f``, ``G``, both results
are then returned.
"""
from itertools import repeat
h = f
T = list(G)
if phantom is not None:
# "phantom" variables with suffix p
hp = phantom[0]
Tp = list(phantom[1])
phantom = True
else:
Tp = repeat([])
phantom = False
while h:
# TODO better data structure!!!
Th = [(g, sdm_ecart(g), gp) for g, gp in zip(T, Tp)
if sdm_monomial_divides(sdm_LM(g), sdm_LM(h))]
if not Th:
break
g, _, gp = min(Th, key=lambda x: x[1])
if sdm_ecart(g) > sdm_ecart(h):
T.append(h)
if phantom:
Tp.append(hp)
if phantom:
h, hp = sdm_spoly(h, g, O, K, phantom=(hp, gp))
else:
h = sdm_spoly(h, g, O, K)
if phantom:
return h, hp
return h
def sdm_nf_buchberger(f, G, O, K, phantom=None):
r"""
Compute a weak normal form of ``f`` with respect to ``G`` and order ``O``.
The ground field is assumed to be ``K``, and monomials ordered according to
``O``.
This is the standard Buchberger algorithm for computing weak normal forms with
respect to *global* monomial orders [SCA, algorithm 1.6.10].
If ``phantom`` is not ``None``, it should be a pair of "phantom" arguments
on which to perform the same computations as on ``f``, ``G``, both results
are then returned.
"""
from itertools import repeat
h = f
T = list(G)
if phantom is not None:
# "phantom" variables with suffix p
hp = phantom[0]
Tp = list(phantom[1])
phantom = True
else:
Tp = repeat([])
phantom = False
while h:
try:
g, gp = next((g, gp) for g, gp in zip(T, Tp)
if sdm_monomial_divides(sdm_LM(g), sdm_LM(h)))
except StopIteration:
break
if phantom:
h, hp = sdm_spoly(h, g, O, K, phantom=(hp, gp))
else:
h = sdm_spoly(h, g, O, K)
if phantom:
return h, hp
return h
def sdm_nf_buchberger_reduced(f, G, O, K):
r"""
Compute a reduced normal form of ``f`` with respect to ``G`` and order ``O``.
The ground field is assumed to be ``K``, and monomials ordered according to
``O``.
In contrast to weak normal forms, reduced normal forms *are* unique, but
their computation is more expensive.
This is the standard Buchberger algorithm for computing reduced normal forms
with respect to *global* monomial orders [SCA, algorithm 1.6.11].
The ``pantom`` option is not supported, so this normal form cannot be used
as a normal form for the "extended" groebner algorithm.
"""
h = sdm_zero()
g = f
while g:
g = sdm_nf_buchberger(g, G, O, K)
if g:
h = sdm_add(h, [sdm_LT(g)], O, K)
g = g[1:]
return h
def sdm_groebner(G, NF, O, K, extended=False):
"""
Compute a minimal standard basis of ``G`` with respect to order ``O``.
The algorithm uses a normal form ``NF``, for example ``sdm_nf_mora``.
The ground field is assumed to be ``K``, and monomials ordered according
to ``O``.
Let `N` denote the submodule generated by elements of `G`. A standard
basis for `N` is a subset `S` of `N`, such that `in(S) = in(N)`, where for
any subset `X` of `F`, `in(X)` denotes the submodule generated by the
initial forms of elements of `X`. [SCA, defn 2.3.2]
A standard basis is called minimal if no subset of it is a standard basis.
One may show that standard bases are always generating sets.
Minimal standard bases are not unique. This algorithm computes a
deterministic result, depending on the particular order of `G`.
If ``extended=True``, also compute the transition matrix from the initial
generators to the groebner basis. That is, return a list of coefficient
vectors, expressing the elements of the groebner basis in terms of the
elements of ``G``.
This functions implements the "sugar" strategy, see
Giovini et al: "One sugar cube, please" OR Selection strategies in
Buchberger algorithm.
"""
# The critical pair set.
# A critical pair is stored as (i, j, s, t) where (i, j) defines the pair
# (by indexing S), s is the sugar of the pair, and t is the lcm of their
# leading monomials.
P = []
# The eventual standard basis.
S = []
Sugars = []
def Ssugar(i, j):
"""Compute the sugar of the S-poly corresponding to (i, j)."""
LMi = sdm_LM(S[i])
LMj = sdm_LM(S[j])
return max(Sugars[i] - sdm_monomial_deg(LMi),
Sugars[j] - sdm_monomial_deg(LMj)) \
+ sdm_monomial_deg(sdm_monomial_lcm(LMi, LMj))
ourkey = lambda p: (p[2], O(p[3]), p[1])
def update(f, sugar, P):
"""Add f with sugar ``sugar`` to S, update P."""
if not f:
return P
k = len(S)
S.append(f)
Sugars.append(sugar)
LMf = sdm_LM(f)
def removethis(pair):
i, j, s, t = pair
if LMf[0] != t[0]:
return False
tik = sdm_monomial_lcm(LMf, sdm_LM(S[i]))
tjk = sdm_monomial_lcm(LMf, sdm_LM(S[j]))
return tik != t and tjk != t and sdm_monomial_divides(tik, t) and \
sdm_monomial_divides(tjk, t)
# apply the chain criterion
P = [p for p in P if not removethis(p)]
# new-pair set
N = [(i, k, Ssugar(i, k), sdm_monomial_lcm(LMf, sdm_LM(S[i])))
for i in range(k) if LMf[0] == sdm_LM(S[i])[0]]
# TODO apply the product criterion?
N.sort(key=ourkey)
remove = set()
for i, p in enumerate(N):
for j in range(i + 1, len(N)):
if sdm_monomial_divides(p[3], N[j][3]):
remove.add(j)
# TODO mergesort?
P.extend(reversed([p for i, p in enumerate(N) if i not in remove]))
P.sort(key=ourkey, reverse=True)
# NOTE reverse-sort, because we want to pop from the end
return P
# Figure out the number of generators in the ground ring.
try:
# NOTE: we look for the first non-zero vector, take its first monomial
# the number of generators in the ring is one less than the length
# (since the zeroth entry is for the module generators)
numgens = len(next(x[0] for x in G if x)[0]) - 1
except StopIteration:
# No non-zero elements in G ...
if extended:
return [], []
return []
# This list will store expressions of the elements of S in terms of the
# initial generators
coefficients = []
# First add all the elements of G to S
for i, f in enumerate(G):
P = update(f, sdm_deg(f), P)
if extended and f:
coefficients.append(sdm_from_dict({(i,) + (0,)*numgens: K(1)}, O))
# Now carry out the buchberger algorithm.
while P:
i, j, s, t = P.pop()
f, g = S[i], S[j]
if extended:
sp, coeff = sdm_spoly(f, g, O, K,
phantom=(coefficients[i], coefficients[j]))
h, hcoeff = NF(sp, S, O, K, phantom=(coeff, coefficients))
if h:
coefficients.append(hcoeff)
else:
h = NF(sdm_spoly(f, g, O, K), S, O, K)
P = update(h, Ssugar(i, j), P)
# Finally interreduce the standard basis.
# (TODO again, better data structures)
S = {(tuple(f), i) for i, f in enumerate(S)}
for (a, ai), (b, bi) in permutations(S, 2):
A = sdm_LM(a)
B = sdm_LM(b)
if sdm_monomial_divides(A, B) and (b, bi) in S and (a, ai) in S:
S.remove((b, bi))
L = sorted(((list(f), i) for f, i in S), key=lambda p: O(sdm_LM(p[0])),
reverse=True)
res = [x[0] for x in L]
if extended:
return res, [coefficients[i] for _, i in L]
return res
PK ]ZZZ����6 6 sympy/polys/domainmatrix.py"""
Stub module to expose DomainMatrix which has now moved to
sympy.polys.matrices package. It should now be imported as:
>>> from sympy.polys.matrices import DomainMatrix
This module might be removed in future.
"""
from sympy.polys.matrices.domainmatrix import DomainMatrix
__all__ = ['DomainMatrix']
PK ]ZZZݒ%]P� P� sympy/polys/euclidtools.py"""Euclidean algorithms, GCDs, LCMs and polynomial remainder sequences. """
from sympy.polys.densearith import (
dup_sub_mul,
dup_neg, dmp_neg,
dmp_add,
dmp_sub,
dup_mul, dmp_mul,
dmp_pow,
dup_div, dmp_div,
dup_rem,
dup_quo, dmp_quo,
dup_prem, dmp_prem,
dup_mul_ground, dmp_mul_ground,
dmp_mul_term,
dup_quo_ground, dmp_quo_ground,
dup_max_norm, dmp_max_norm)
from sympy.polys.densebasic import (
dup_strip, dmp_raise,
dmp_zero, dmp_one, dmp_ground,
dmp_one_p, dmp_zero_p,
dmp_zeros,
dup_degree, dmp_degree, dmp_degree_in,
dup_LC, dmp_LC, dmp_ground_LC,
dmp_multi_deflate, dmp_inflate,
dup_convert, dmp_convert,
dmp_apply_pairs)
from sympy.polys.densetools import (
dup_clear_denoms, dmp_clear_denoms,
dup_diff, dmp_diff,
dup_eval, dmp_eval, dmp_eval_in,
dup_trunc, dmp_ground_trunc,
dup_monic, dmp_ground_monic,
dup_primitive, dmp_ground_primitive,
dup_extract, dmp_ground_extract)
from sympy.polys.galoistools import (
gf_int, gf_crt)
from sympy.polys.polyconfig import query
from sympy.polys.polyerrors import (
MultivariatePolynomialError,
HeuristicGCDFailed,
HomomorphismFailed,
NotInvertible,
DomainError)
def dup_half_gcdex(f, g, K):
"""
Half extended Euclidean algorithm in `F[x]`.
Returns ``(s, h)`` such that ``h = gcd(f, g)`` and ``s*f = h (mod g)``.
Examples
========
>>> from sympy.polys import ring, QQ
>>> R, x = ring("x", QQ)
>>> f = x**4 - 2*x**3 - 6*x**2 + 12*x + 15
>>> g = x**3 + x**2 - 4*x - 4
>>> R.dup_half_gcdex(f, g)
(-1/5*x + 3/5, x + 1)
"""
if not K.is_Field:
raise DomainError("Cannot compute half extended GCD over %s" % K)
a, b = [K.one], []
while g:
q, r = dup_div(f, g, K)
f, g = g, r
a, b = b, dup_sub_mul(a, q, b, K)
a = dup_quo_ground(a, dup_LC(f, K), K)
f = dup_monic(f, K)
return a, f
def dmp_half_gcdex(f, g, u, K):
"""
Half extended Euclidean algorithm in `F[X]`.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
"""
if not u:
return dup_half_gcdex(f, g, K)
else:
raise MultivariatePolynomialError(f, g)
def dup_gcdex(f, g, K):
"""
Extended Euclidean algorithm in `F[x]`.
Returns ``(s, t, h)`` such that ``h = gcd(f, g)`` and ``s*f + t*g = h``.
Examples
========
>>> from sympy.polys import ring, QQ
>>> R, x = ring("x", QQ)
>>> f = x**4 - 2*x**3 - 6*x**2 + 12*x + 15
>>> g = x**3 + x**2 - 4*x - 4
>>> R.dup_gcdex(f, g)
(-1/5*x + 3/5, 1/5*x**2 - 6/5*x + 2, x + 1)
"""
s, h = dup_half_gcdex(f, g, K)
F = dup_sub_mul(h, s, f, K)
t = dup_quo(F, g, K)
return s, t, h
def dmp_gcdex(f, g, u, K):
"""
Extended Euclidean algorithm in `F[X]`.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
"""
if not u:
return dup_gcdex(f, g, K)
else:
raise MultivariatePolynomialError(f, g)
def dup_invert(f, g, K):
"""
Compute multiplicative inverse of `f` modulo `g` in `F[x]`.
Examples
========
>>> from sympy.polys import ring, QQ
>>> R, x = ring("x", QQ)
>>> f = x**2 - 1
>>> g = 2*x - 1
>>> h = x - 1
>>> R.dup_invert(f, g)
-4/3
>>> R.dup_invert(f, h)
Traceback (most recent call last):
...
NotInvertible: zero divisor
"""
s, h = dup_half_gcdex(f, g, K)
if h == [K.one]:
return dup_rem(s, g, K)
else:
raise NotInvertible("zero divisor")
def dmp_invert(f, g, u, K):
"""
Compute multiplicative inverse of `f` modulo `g` in `F[X]`.
Examples
========
>>> from sympy.polys import ring, QQ
>>> R, x = ring("x", QQ)
"""
if not u:
return dup_invert(f, g, K)
else:
raise MultivariatePolynomialError(f, g)
def dup_euclidean_prs(f, g, K):
"""
Euclidean polynomial remainder sequence (PRS) in `K[x]`.
Examples
========
>>> from sympy.polys import ring, QQ
>>> R, x = ring("x", QQ)
>>> f = x**8 + x**6 - 3*x**4 - 3*x**3 + 8*x**2 + 2*x - 5
>>> g = 3*x**6 + 5*x**4 - 4*x**2 - 9*x + 21
>>> prs = R.dup_euclidean_prs(f, g)
>>> prs[0]
x**8 + x**6 - 3*x**4 - 3*x**3 + 8*x**2 + 2*x - 5
>>> prs[1]
3*x**6 + 5*x**4 - 4*x**2 - 9*x + 21
>>> prs[2]
-5/9*x**4 + 1/9*x**2 - 1/3
>>> prs[3]
-117/25*x**2 - 9*x + 441/25
>>> prs[4]
233150/19773*x - 102500/6591
>>> prs[5]
-1288744821/543589225
"""
prs = [f, g]
h = dup_rem(f, g, K)
while h:
prs.append(h)
f, g = g, h
h = dup_rem(f, g, K)
return prs
def dmp_euclidean_prs(f, g, u, K):
"""
Euclidean polynomial remainder sequence (PRS) in `K[X]`.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
"""
if not u:
return dup_euclidean_prs(f, g, K)
else:
raise MultivariatePolynomialError(f, g)
def dup_primitive_prs(f, g, K):
"""
Primitive polynomial remainder sequence (PRS) in `K[x]`.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> f = x**8 + x**6 - 3*x**4 - 3*x**3 + 8*x**2 + 2*x - 5
>>> g = 3*x**6 + 5*x**4 - 4*x**2 - 9*x + 21
>>> prs = R.dup_primitive_prs(f, g)
>>> prs[0]
x**8 + x**6 - 3*x**4 - 3*x**3 + 8*x**2 + 2*x - 5
>>> prs[1]
3*x**6 + 5*x**4 - 4*x**2 - 9*x + 21
>>> prs[2]
-5*x**4 + x**2 - 3
>>> prs[3]
13*x**2 + 25*x - 49
>>> prs[4]
4663*x - 6150
>>> prs[5]
1
"""
prs = [f, g]
_, h = dup_primitive(dup_prem(f, g, K), K)
while h:
prs.append(h)
f, g = g, h
_, h = dup_primitive(dup_prem(f, g, K), K)
return prs
def dmp_primitive_prs(f, g, u, K):
"""
Primitive polynomial remainder sequence (PRS) in `K[X]`.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
"""
if not u:
return dup_primitive_prs(f, g, K)
else:
raise MultivariatePolynomialError(f, g)
def dup_inner_subresultants(f, g, K):
"""
Subresultant PRS algorithm in `K[x]`.
Computes the subresultant polynomial remainder sequence (PRS)
and the non-zero scalar subresultants of `f` and `g`.
By [1] Thm. 3, these are the constants '-c' (- to optimize
computation of sign).
The first subdeterminant is set to 1 by convention to match
the polynomial and the scalar subdeterminants.
If 'deg(f) < deg(g)', the subresultants of '(g,f)' are computed.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_inner_subresultants(x**2 + 1, x**2 - 1)
([x**2 + 1, x**2 - 1, -2], [1, 1, 4])
References
==========
.. [1] W.S. Brown, The Subresultant PRS Algorithm.
ACM Transaction of Mathematical Software 4 (1978) 237-249
"""
n = dup_degree(f)
m = dup_degree(g)
if n < m:
f, g = g, f
n, m = m, n
if not f:
return [], []
if not g:
return [f], [K.one]
R = [f, g]
d = n - m
b = (-K.one)**(d + 1)
h = dup_prem(f, g, K)
h = dup_mul_ground(h, b, K)
lc = dup_LC(g, K)
c = lc**d
# Conventional first scalar subdeterminant is 1
S = [K.one, c]
c = -c
while h:
k = dup_degree(h)
R.append(h)
f, g, m, d = g, h, k, m - k
b = -lc * c**d
h = dup_prem(f, g, K)
h = dup_quo_ground(h, b, K)
lc = dup_LC(g, K)
if d > 1: # abnormal case
q = c**(d - 1)
c = K.quo((-lc)**d, q)
else:
c = -lc
S.append(-c)
return R, S
def dup_subresultants(f, g, K):
"""
Computes subresultant PRS of two polynomials in `K[x]`.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_subresultants(x**2 + 1, x**2 - 1)
[x**2 + 1, x**2 - 1, -2]
"""
return dup_inner_subresultants(f, g, K)[0]
def dup_prs_resultant(f, g, K):
"""
Resultant algorithm in `K[x]` using subresultant PRS.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_prs_resultant(x**2 + 1, x**2 - 1)
(4, [x**2 + 1, x**2 - 1, -2])
"""
if not f or not g:
return (K.zero, [])
R, S = dup_inner_subresultants(f, g, K)
if dup_degree(R[-1]) > 0:
return (K.zero, R)
return S[-1], R
def dup_resultant(f, g, K, includePRS=False):
"""
Computes resultant of two polynomials in `K[x]`.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_resultant(x**2 + 1, x**2 - 1)
4
"""
if includePRS:
return dup_prs_resultant(f, g, K)
return dup_prs_resultant(f, g, K)[0]
def dmp_inner_subresultants(f, g, u, K):
"""
Subresultant PRS algorithm in `K[X]`.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> f = 3*x**2*y - y**3 - 4
>>> g = x**2 + x*y**3 - 9
>>> a = 3*x*y**4 + y**3 - 27*y + 4
>>> b = -3*y**10 - 12*y**7 + y**6 - 54*y**4 + 8*y**3 + 729*y**2 - 216*y + 16
>>> prs = [f, g, a, b]
>>> sres = [[1], [1], [3, 0, 0, 0, 0], [-3, 0, 0, -12, 1, 0, -54, 8, 729, -216, 16]]
>>> R.dmp_inner_subresultants(f, g) == (prs, sres)
True
"""
if not u:
return dup_inner_subresultants(f, g, K)
n = dmp_degree(f, u)
m = dmp_degree(g, u)
if n < m:
f, g = g, f
n, m = m, n
if dmp_zero_p(f, u):
return [], []
v = u - 1
if dmp_zero_p(g, u):
return [f], [dmp_ground(K.one, v)]
R = [f, g]
d = n - m
b = dmp_pow(dmp_ground(-K.one, v), d + 1, v, K)
h = dmp_prem(f, g, u, K)
h = dmp_mul_term(h, b, 0, u, K)
lc = dmp_LC(g, K)
c = dmp_pow(lc, d, v, K)
S = [dmp_ground(K.one, v), c]
c = dmp_neg(c, v, K)
while not dmp_zero_p(h, u):
k = dmp_degree(h, u)
R.append(h)
f, g, m, d = g, h, k, m - k
b = dmp_mul(dmp_neg(lc, v, K),
dmp_pow(c, d, v, K), v, K)
h = dmp_prem(f, g, u, K)
h = [ dmp_quo(ch, b, v, K) for ch in h ]
lc = dmp_LC(g, K)
if d > 1:
p = dmp_pow(dmp_neg(lc, v, K), d, v, K)
q = dmp_pow(c, d - 1, v, K)
c = dmp_quo(p, q, v, K)
else:
c = dmp_neg(lc, v, K)
S.append(dmp_neg(c, v, K))
return R, S
def dmp_subresultants(f, g, u, K):
"""
Computes subresultant PRS of two polynomials in `K[X]`.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> f = 3*x**2*y - y**3 - 4
>>> g = x**2 + x*y**3 - 9
>>> a = 3*x*y**4 + y**3 - 27*y + 4
>>> b = -3*y**10 - 12*y**7 + y**6 - 54*y**4 + 8*y**3 + 729*y**2 - 216*y + 16
>>> R.dmp_subresultants(f, g) == [f, g, a, b]
True
"""
return dmp_inner_subresultants(f, g, u, K)[0]
def dmp_prs_resultant(f, g, u, K):
"""
Resultant algorithm in `K[X]` using subresultant PRS.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> f = 3*x**2*y - y**3 - 4
>>> g = x**2 + x*y**3 - 9
>>> a = 3*x*y**4 + y**3 - 27*y + 4
>>> b = -3*y**10 - 12*y**7 + y**6 - 54*y**4 + 8*y**3 + 729*y**2 - 216*y + 16
>>> res, prs = R.dmp_prs_resultant(f, g)
>>> res == b # resultant has n-1 variables
False
>>> res == b.drop(x)
True
>>> prs == [f, g, a, b]
True
"""
if not u:
return dup_prs_resultant(f, g, K)
if dmp_zero_p(f, u) or dmp_zero_p(g, u):
return (dmp_zero(u - 1), [])
R, S = dmp_inner_subresultants(f, g, u, K)
if dmp_degree(R[-1], u) > 0:
return (dmp_zero(u - 1), R)
return S[-1], R
def dmp_zz_modular_resultant(f, g, p, u, K):
"""
Compute resultant of `f` and `g` modulo a prime `p`.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> f = x + y + 2
>>> g = 2*x*y + x + 3
>>> R.dmp_zz_modular_resultant(f, g, 5)
-2*y**2 + 1
"""
if not u:
return gf_int(dup_prs_resultant(f, g, K)[0] % p, p)
v = u - 1
n = dmp_degree(f, u)
m = dmp_degree(g, u)
N = dmp_degree_in(f, 1, u)
M = dmp_degree_in(g, 1, u)
B = n*M + m*N
D, a = [K.one], -K.one
r = dmp_zero(v)
while dup_degree(D) <= B:
while True:
a += K.one
if a == p:
raise HomomorphismFailed('no luck')
F = dmp_eval_in(f, gf_int(a, p), 1, u, K)
if dmp_degree(F, v) == n:
G = dmp_eval_in(g, gf_int(a, p), 1, u, K)
if dmp_degree(G, v) == m:
break
R = dmp_zz_modular_resultant(F, G, p, v, K)
e = dmp_eval(r, a, v, K)
if not v:
R = dup_strip([R])
e = dup_strip([e])
else:
R = [R]
e = [e]
d = K.invert(dup_eval(D, a, K), p)
d = dup_mul_ground(D, d, K)
d = dmp_raise(d, v, 0, K)
c = dmp_mul(d, dmp_sub(R, e, v, K), v, K)
r = dmp_add(r, c, v, K)
r = dmp_ground_trunc(r, p, v, K)
D = dup_mul(D, [K.one, -a], K)
D = dup_trunc(D, p, K)
return r
def _collins_crt(r, R, P, p, K):
"""Wrapper of CRT for Collins's resultant algorithm. """
return gf_int(gf_crt([r, R], [P, p], K), P*p)
def dmp_zz_collins_resultant(f, g, u, K):
"""
Collins's modular resultant algorithm in `Z[X]`.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> f = x + y + 2
>>> g = 2*x*y + x + 3
>>> R.dmp_zz_collins_resultant(f, g)
-2*y**2 - 5*y + 1
"""
n = dmp_degree(f, u)
m = dmp_degree(g, u)
if n < 0 or m < 0:
return dmp_zero(u - 1)
A = dmp_max_norm(f, u, K)
B = dmp_max_norm(g, u, K)
a = dmp_ground_LC(f, u, K)
b = dmp_ground_LC(g, u, K)
v = u - 1
B = K(2)*K.factorial(K(n + m))*A**m*B**n
r, p, P = dmp_zero(v), K.one, K.one
from sympy.ntheory import nextprime
while P <= B:
p = K(nextprime(p))
while not (a % p) or not (b % p):
p = K(nextprime(p))
F = dmp_ground_trunc(f, p, u, K)
G = dmp_ground_trunc(g, p, u, K)
try:
R = dmp_zz_modular_resultant(F, G, p, u, K)
except HomomorphismFailed:
continue
if K.is_one(P):
r = R
else:
r = dmp_apply_pairs(r, R, _collins_crt, (P, p, K), v, K)
P *= p
return r
def dmp_qq_collins_resultant(f, g, u, K0):
"""
Collins's modular resultant algorithm in `Q[X]`.
Examples
========
>>> from sympy.polys import ring, QQ
>>> R, x,y = ring("x,y", QQ)
>>> f = QQ(1,2)*x + y + QQ(2,3)
>>> g = 2*x*y + x + 3
>>> R.dmp_qq_collins_resultant(f, g)
-2*y**2 - 7/3*y + 5/6
"""
n = dmp_degree(f, u)
m = dmp_degree(g, u)
if n < 0 or m < 0:
return dmp_zero(u - 1)
K1 = K0.get_ring()
cf, f = dmp_clear_denoms(f, u, K0, K1)
cg, g = dmp_clear_denoms(g, u, K0, K1)
f = dmp_convert(f, u, K0, K1)
g = dmp_convert(g, u, K0, K1)
r = dmp_zz_collins_resultant(f, g, u, K1)
r = dmp_convert(r, u - 1, K1, K0)
c = K0.convert(cf**m * cg**n, K1)
return dmp_quo_ground(r, c, u - 1, K0)
def dmp_resultant(f, g, u, K, includePRS=False):
"""
Computes resultant of two polynomials in `K[X]`.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> f = 3*x**2*y - y**3 - 4
>>> g = x**2 + x*y**3 - 9
>>> R.dmp_resultant(f, g)
-3*y**10 - 12*y**7 + y**6 - 54*y**4 + 8*y**3 + 729*y**2 - 216*y + 16
"""
if not u:
return dup_resultant(f, g, K, includePRS=includePRS)
if includePRS:
return dmp_prs_resultant(f, g, u, K)
if K.is_Field:
if K.is_QQ and query('USE_COLLINS_RESULTANT'):
return dmp_qq_collins_resultant(f, g, u, K)
else:
if K.is_ZZ and query('USE_COLLINS_RESULTANT'):
return dmp_zz_collins_resultant(f, g, u, K)
return dmp_prs_resultant(f, g, u, K)[0]
def dup_discriminant(f, K):
"""
Computes discriminant of a polynomial in `K[x]`.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_discriminant(x**2 + 2*x + 3)
-8
"""
d = dup_degree(f)
if d <= 0:
return K.zero
else:
s = (-1)**((d*(d - 1)) // 2)
c = dup_LC(f, K)
r = dup_resultant(f, dup_diff(f, 1, K), K)
return K.quo(r, c*K(s))
def dmp_discriminant(f, u, K):
"""
Computes discriminant of a polynomial in `K[X]`.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y,z,t = ring("x,y,z,t", ZZ)
>>> R.dmp_discriminant(x**2*y + x*z + t)
-4*y*t + z**2
"""
if not u:
return dup_discriminant(f, K)
d, v = dmp_degree(f, u), u - 1
if d <= 0:
return dmp_zero(v)
else:
s = (-1)**((d*(d - 1)) // 2)
c = dmp_LC(f, K)
r = dmp_resultant(f, dmp_diff(f, 1, u, K), u, K)
c = dmp_mul_ground(c, K(s), v, K)
return dmp_quo(r, c, v, K)
def _dup_rr_trivial_gcd(f, g, K):
"""Handle trivial cases in GCD algorithm over a ring. """
if not (f or g):
return [], [], []
elif not f:
if K.is_nonnegative(dup_LC(g, K)):
return g, [], [K.one]
else:
return dup_neg(g, K), [], [-K.one]
elif not g:
if K.is_nonnegative(dup_LC(f, K)):
return f, [K.one], []
else:
return dup_neg(f, K), [-K.one], []
return None
def _dup_ff_trivial_gcd(f, g, K):
"""Handle trivial cases in GCD algorithm over a field. """
if not (f or g):
return [], [], []
elif not f:
return dup_monic(g, K), [], [dup_LC(g, K)]
elif not g:
return dup_monic(f, K), [dup_LC(f, K)], []
else:
return None
def _dmp_rr_trivial_gcd(f, g, u, K):
"""Handle trivial cases in GCD algorithm over a ring. """
zero_f = dmp_zero_p(f, u)
zero_g = dmp_zero_p(g, u)
if_contain_one = dmp_one_p(f, u, K) or dmp_one_p(g, u, K)
if zero_f and zero_g:
return tuple(dmp_zeros(3, u, K))
elif zero_f:
if K.is_nonnegative(dmp_ground_LC(g, u, K)):
return g, dmp_zero(u), dmp_one(u, K)
else:
return dmp_neg(g, u, K), dmp_zero(u), dmp_ground(-K.one, u)
elif zero_g:
if K.is_nonnegative(dmp_ground_LC(f, u, K)):
return f, dmp_one(u, K), dmp_zero(u)
else:
return dmp_neg(f, u, K), dmp_ground(-K.one, u), dmp_zero(u)
elif if_contain_one:
return dmp_one(u, K), f, g
elif query('USE_SIMPLIFY_GCD'):
return _dmp_simplify_gcd(f, g, u, K)
else:
return None
def _dmp_ff_trivial_gcd(f, g, u, K):
"""Handle trivial cases in GCD algorithm over a field. """
zero_f = dmp_zero_p(f, u)
zero_g = dmp_zero_p(g, u)
if zero_f and zero_g:
return tuple(dmp_zeros(3, u, K))
elif zero_f:
return (dmp_ground_monic(g, u, K),
dmp_zero(u),
dmp_ground(dmp_ground_LC(g, u, K), u))
elif zero_g:
return (dmp_ground_monic(f, u, K),
dmp_ground(dmp_ground_LC(f, u, K), u),
dmp_zero(u))
elif query('USE_SIMPLIFY_GCD'):
return _dmp_simplify_gcd(f, g, u, K)
else:
return None
def _dmp_simplify_gcd(f, g, u, K):
"""Try to eliminate `x_0` from GCD computation in `K[X]`. """
df = dmp_degree(f, u)
dg = dmp_degree(g, u)
if df > 0 and dg > 0:
return None
if not (df or dg):
F = dmp_LC(f, K)
G = dmp_LC(g, K)
else:
if not df:
F = dmp_LC(f, K)
G = dmp_content(g, u, K)
else:
F = dmp_content(f, u, K)
G = dmp_LC(g, K)
v = u - 1
h = dmp_gcd(F, G, v, K)
cff = [ dmp_quo(cf, h, v, K) for cf in f ]
cfg = [ dmp_quo(cg, h, v, K) for cg in g ]
return [h], cff, cfg
def dup_rr_prs_gcd(f, g, K):
"""
Computes polynomial GCD using subresultants over a ring.
Returns ``(h, cff, cfg)`` such that ``a = gcd(f, g)``, ``cff = quo(f, h)``,
and ``cfg = quo(g, h)``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_rr_prs_gcd(x**2 - 1, x**2 - 3*x + 2)
(x - 1, x + 1, x - 2)
"""
result = _dup_rr_trivial_gcd(f, g, K)
if result is not None:
return result
fc, F = dup_primitive(f, K)
gc, G = dup_primitive(g, K)
c = K.gcd(fc, gc)
h = dup_subresultants(F, G, K)[-1]
_, h = dup_primitive(h, K)
c *= K.canonical_unit(dup_LC(h, K))
h = dup_mul_ground(h, c, K)
cff = dup_quo(f, h, K)
cfg = dup_quo(g, h, K)
return h, cff, cfg
def dup_ff_prs_gcd(f, g, K):
"""
Computes polynomial GCD using subresultants over a field.
Returns ``(h, cff, cfg)`` such that ``a = gcd(f, g)``, ``cff = quo(f, h)``,
and ``cfg = quo(g, h)``.
Examples
========
>>> from sympy.polys import ring, QQ
>>> R, x = ring("x", QQ)
>>> R.dup_ff_prs_gcd(x**2 - 1, x**2 - 3*x + 2)
(x - 1, x + 1, x - 2)
"""
result = _dup_ff_trivial_gcd(f, g, K)
if result is not None:
return result
h = dup_subresultants(f, g, K)[-1]
h = dup_monic(h, K)
cff = dup_quo(f, h, K)
cfg = dup_quo(g, h, K)
return h, cff, cfg
def dmp_rr_prs_gcd(f, g, u, K):
"""
Computes polynomial GCD using subresultants over a ring.
Returns ``(h, cff, cfg)`` such that ``a = gcd(f, g)``, ``cff = quo(f, h)``,
and ``cfg = quo(g, h)``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y, = ring("x,y", ZZ)
>>> f = x**2 + 2*x*y + y**2
>>> g = x**2 + x*y
>>> R.dmp_rr_prs_gcd(f, g)
(x + y, x + y, x)
"""
if not u:
return dup_rr_prs_gcd(f, g, K)
result = _dmp_rr_trivial_gcd(f, g, u, K)
if result is not None:
return result
fc, F = dmp_primitive(f, u, K)
gc, G = dmp_primitive(g, u, K)
h = dmp_subresultants(F, G, u, K)[-1]
c, _, _ = dmp_rr_prs_gcd(fc, gc, u - 1, K)
_, h = dmp_primitive(h, u, K)
h = dmp_mul_term(h, c, 0, u, K)
unit = K.canonical_unit(dmp_ground_LC(h, u, K))
if unit != K.one:
h = dmp_mul_ground(h, unit, u, K)
cff = dmp_quo(f, h, u, K)
cfg = dmp_quo(g, h, u, K)
return h, cff, cfg
def dmp_ff_prs_gcd(f, g, u, K):
"""
Computes polynomial GCD using subresultants over a field.
Returns ``(h, cff, cfg)`` such that ``a = gcd(f, g)``, ``cff = quo(f, h)``,
and ``cfg = quo(g, h)``.
Examples
========
>>> from sympy.polys import ring, QQ
>>> R, x,y, = ring("x,y", QQ)
>>> f = QQ(1,2)*x**2 + x*y + QQ(1,2)*y**2
>>> g = x**2 + x*y
>>> R.dmp_ff_prs_gcd(f, g)
(x + y, 1/2*x + 1/2*y, x)
"""
if not u:
return dup_ff_prs_gcd(f, g, K)
result = _dmp_ff_trivial_gcd(f, g, u, K)
if result is not None:
return result
fc, F = dmp_primitive(f, u, K)
gc, G = dmp_primitive(g, u, K)
h = dmp_subresultants(F, G, u, K)[-1]
c, _, _ = dmp_ff_prs_gcd(fc, gc, u - 1, K)
_, h = dmp_primitive(h, u, K)
h = dmp_mul_term(h, c, 0, u, K)
h = dmp_ground_monic(h, u, K)
cff = dmp_quo(f, h, u, K)
cfg = dmp_quo(g, h, u, K)
return h, cff, cfg
HEU_GCD_MAX = 6
def _dup_zz_gcd_interpolate(h, x, K):
"""Interpolate polynomial GCD from integer GCD. """
f = []
while h:
g = h % x
if g > x // 2:
g -= x
f.insert(0, g)
h = (h - g) // x
return f
def dup_zz_heu_gcd(f, g, K):
"""
Heuristic polynomial GCD in `Z[x]`.
Given univariate polynomials `f` and `g` in `Z[x]`, returns
their GCD and cofactors, i.e. polynomials ``h``, ``cff`` and ``cfg``
such that::
h = gcd(f, g), cff = quo(f, h) and cfg = quo(g, h)
The algorithm is purely heuristic which means it may fail to compute
the GCD. This will be signaled by raising an exception. In this case
you will need to switch to another GCD method.
The algorithm computes the polynomial GCD by evaluating polynomials
f and g at certain points and computing (fast) integer GCD of those
evaluations. The polynomial GCD is recovered from the integer image
by interpolation. The final step is to verify if the result is the
correct GCD. This gives cofactors as a side effect.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_zz_heu_gcd(x**2 - 1, x**2 - 3*x + 2)
(x - 1, x + 1, x - 2)
References
==========
.. [1] [Liao95]_
"""
result = _dup_rr_trivial_gcd(f, g, K)
if result is not None:
return result
df = dup_degree(f)
dg = dup_degree(g)
gcd, f, g = dup_extract(f, g, K)
if df == 0 or dg == 0:
return [gcd], f, g
f_norm = dup_max_norm(f, K)
g_norm = dup_max_norm(g, K)
B = K(2*min(f_norm, g_norm) + 29)
x = max(min(B, 99*K.sqrt(B)),
2*min(f_norm // abs(dup_LC(f, K)),
g_norm // abs(dup_LC(g, K))) + 4)
for i in range(0, HEU_GCD_MAX):
ff = dup_eval(f, x, K)
gg = dup_eval(g, x, K)
if ff and gg:
h = K.gcd(ff, gg)
cff = ff // h
cfg = gg // h
h = _dup_zz_gcd_interpolate(h, x, K)
h = dup_primitive(h, K)[1]
cff_, r = dup_div(f, h, K)
if not r:
cfg_, r = dup_div(g, h, K)
if not r:
h = dup_mul_ground(h, gcd, K)
return h, cff_, cfg_
cff = _dup_zz_gcd_interpolate(cff, x, K)
h, r = dup_div(f, cff, K)
if not r:
cfg_, r = dup_div(g, h, K)
if not r:
h = dup_mul_ground(h, gcd, K)
return h, cff, cfg_
cfg = _dup_zz_gcd_interpolate(cfg, x, K)
h, r = dup_div(g, cfg, K)
if not r:
cff_, r = dup_div(f, h, K)
if not r:
h = dup_mul_ground(h, gcd, K)
return h, cff_, cfg
x = 73794*x * K.sqrt(K.sqrt(x)) // 27011
raise HeuristicGCDFailed('no luck')
def _dmp_zz_gcd_interpolate(h, x, v, K):
"""Interpolate polynomial GCD from integer GCD. """
f = []
while not dmp_zero_p(h, v):
g = dmp_ground_trunc(h, x, v, K)
f.insert(0, g)
h = dmp_sub(h, g, v, K)
h = dmp_quo_ground(h, x, v, K)
if K.is_negative(dmp_ground_LC(f, v + 1, K)):
return dmp_neg(f, v + 1, K)
else:
return f
def dmp_zz_heu_gcd(f, g, u, K):
"""
Heuristic polynomial GCD in `Z[X]`.
Given univariate polynomials `f` and `g` in `Z[X]`, returns
their GCD and cofactors, i.e. polynomials ``h``, ``cff`` and ``cfg``
such that::
h = gcd(f, g), cff = quo(f, h) and cfg = quo(g, h)
The algorithm is purely heuristic which means it may fail to compute
the GCD. This will be signaled by raising an exception. In this case
you will need to switch to another GCD method.
The algorithm computes the polynomial GCD by evaluating polynomials
f and g at certain points and computing (fast) integer GCD of those
evaluations. The polynomial GCD is recovered from the integer image
by interpolation. The evaluation process reduces f and g variable by
variable into a large integer. The final step is to verify if the
interpolated polynomial is the correct GCD. This gives cofactors of
the input polynomials as a side effect.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y, = ring("x,y", ZZ)
>>> f = x**2 + 2*x*y + y**2
>>> g = x**2 + x*y
>>> R.dmp_zz_heu_gcd(f, g)
(x + y, x + y, x)
References
==========
.. [1] [Liao95]_
"""
if not u:
return dup_zz_heu_gcd(f, g, K)
result = _dmp_rr_trivial_gcd(f, g, u, K)
if result is not None:
return result
gcd, f, g = dmp_ground_extract(f, g, u, K)
f_norm = dmp_max_norm(f, u, K)
g_norm = dmp_max_norm(g, u, K)
B = K(2*min(f_norm, g_norm) + 29)
x = max(min(B, 99*K.sqrt(B)),
2*min(f_norm // abs(dmp_ground_LC(f, u, K)),
g_norm // abs(dmp_ground_LC(g, u, K))) + 4)
for i in range(0, HEU_GCD_MAX):
ff = dmp_eval(f, x, u, K)
gg = dmp_eval(g, x, u, K)
v = u - 1
if not (dmp_zero_p(ff, v) or dmp_zero_p(gg, v)):
h, cff, cfg = dmp_zz_heu_gcd(ff, gg, v, K)
h = _dmp_zz_gcd_interpolate(h, x, v, K)
h = dmp_ground_primitive(h, u, K)[1]
cff_, r = dmp_div(f, h, u, K)
if dmp_zero_p(r, u):
cfg_, r = dmp_div(g, h, u, K)
if dmp_zero_p(r, u):
h = dmp_mul_ground(h, gcd, u, K)
return h, cff_, cfg_
cff = _dmp_zz_gcd_interpolate(cff, x, v, K)
h, r = dmp_div(f, cff, u, K)
if dmp_zero_p(r, u):
cfg_, r = dmp_div(g, h, u, K)
if dmp_zero_p(r, u):
h = dmp_mul_ground(h, gcd, u, K)
return h, cff, cfg_
cfg = _dmp_zz_gcd_interpolate(cfg, x, v, K)
h, r = dmp_div(g, cfg, u, K)
if dmp_zero_p(r, u):
cff_, r = dmp_div(f, h, u, K)
if dmp_zero_p(r, u):
h = dmp_mul_ground(h, gcd, u, K)
return h, cff_, cfg
x = 73794*x * K.sqrt(K.sqrt(x)) // 27011
raise HeuristicGCDFailed('no luck')
def dup_qq_heu_gcd(f, g, K0):
"""
Heuristic polynomial GCD in `Q[x]`.
Returns ``(h, cff, cfg)`` such that ``a = gcd(f, g)``,
``cff = quo(f, h)``, and ``cfg = quo(g, h)``.
Examples
========
>>> from sympy.polys import ring, QQ
>>> R, x = ring("x", QQ)
>>> f = QQ(1,2)*x**2 + QQ(7,4)*x + QQ(3,2)
>>> g = QQ(1,2)*x**2 + x
>>> R.dup_qq_heu_gcd(f, g)
(x + 2, 1/2*x + 3/4, 1/2*x)
"""
result = _dup_ff_trivial_gcd(f, g, K0)
if result is not None:
return result
K1 = K0.get_ring()
cf, f = dup_clear_denoms(f, K0, K1)
cg, g = dup_clear_denoms(g, K0, K1)
f = dup_convert(f, K0, K1)
g = dup_convert(g, K0, K1)
h, cff, cfg = dup_zz_heu_gcd(f, g, K1)
h = dup_convert(h, K1, K0)
c = dup_LC(h, K0)
h = dup_monic(h, K0)
cff = dup_convert(cff, K1, K0)
cfg = dup_convert(cfg, K1, K0)
cff = dup_mul_ground(cff, K0.quo(c, cf), K0)
cfg = dup_mul_ground(cfg, K0.quo(c, cg), K0)
return h, cff, cfg
def dmp_qq_heu_gcd(f, g, u, K0):
"""
Heuristic polynomial GCD in `Q[X]`.
Returns ``(h, cff, cfg)`` such that ``a = gcd(f, g)``,
``cff = quo(f, h)``, and ``cfg = quo(g, h)``.
Examples
========
>>> from sympy.polys import ring, QQ
>>> R, x,y, = ring("x,y", QQ)
>>> f = QQ(1,4)*x**2 + x*y + y**2
>>> g = QQ(1,2)*x**2 + x*y
>>> R.dmp_qq_heu_gcd(f, g)
(x + 2*y, 1/4*x + 1/2*y, 1/2*x)
"""
result = _dmp_ff_trivial_gcd(f, g, u, K0)
if result is not None:
return result
K1 = K0.get_ring()
cf, f = dmp_clear_denoms(f, u, K0, K1)
cg, g = dmp_clear_denoms(g, u, K0, K1)
f = dmp_convert(f, u, K0, K1)
g = dmp_convert(g, u, K0, K1)
h, cff, cfg = dmp_zz_heu_gcd(f, g, u, K1)
h = dmp_convert(h, u, K1, K0)
c = dmp_ground_LC(h, u, K0)
h = dmp_ground_monic(h, u, K0)
cff = dmp_convert(cff, u, K1, K0)
cfg = dmp_convert(cfg, u, K1, K0)
cff = dmp_mul_ground(cff, K0.quo(c, cf), u, K0)
cfg = dmp_mul_ground(cfg, K0.quo(c, cg), u, K0)
return h, cff, cfg
def dup_inner_gcd(f, g, K):
"""
Computes polynomial GCD and cofactors of `f` and `g` in `K[x]`.
Returns ``(h, cff, cfg)`` such that ``a = gcd(f, g)``,
``cff = quo(f, h)``, and ``cfg = quo(g, h)``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_inner_gcd(x**2 - 1, x**2 - 3*x + 2)
(x - 1, x + 1, x - 2)
"""
# XXX: This used to check for K.is_Exact but leads to awkward results when
# the domain is something like RR[z] e.g.:
#
# >>> g, p, q = Poly(1, x).cancel(Poly(51.05*x*y - 1.0, x))
# >>> g
# 1.0
# >>> p
# Poly(17592186044421.0, x, domain='RR[y]')
# >>> q
# Poly(898081097567692.0*y*x - 17592186044421.0, x, domain='RR[y]'))
#
# Maybe it would be better to flatten into multivariate polynomials first.
if K.is_RR or K.is_CC:
try:
exact = K.get_exact()
except DomainError:
return [K.one], f, g
f = dup_convert(f, K, exact)
g = dup_convert(g, K, exact)
h, cff, cfg = dup_inner_gcd(f, g, exact)
h = dup_convert(h, exact, K)
cff = dup_convert(cff, exact, K)
cfg = dup_convert(cfg, exact, K)
return h, cff, cfg
elif K.is_Field:
if K.is_QQ and query('USE_HEU_GCD'):
try:
return dup_qq_heu_gcd(f, g, K)
except HeuristicGCDFailed:
pass
return dup_ff_prs_gcd(f, g, K)
else:
if K.is_ZZ and query('USE_HEU_GCD'):
try:
return dup_zz_heu_gcd(f, g, K)
except HeuristicGCDFailed:
pass
return dup_rr_prs_gcd(f, g, K)
def _dmp_inner_gcd(f, g, u, K):
"""Helper function for `dmp_inner_gcd()`. """
if not K.is_Exact:
try:
exact = K.get_exact()
except DomainError:
return dmp_one(u, K), f, g
f = dmp_convert(f, u, K, exact)
g = dmp_convert(g, u, K, exact)
h, cff, cfg = _dmp_inner_gcd(f, g, u, exact)
h = dmp_convert(h, u, exact, K)
cff = dmp_convert(cff, u, exact, K)
cfg = dmp_convert(cfg, u, exact, K)
return h, cff, cfg
elif K.is_Field:
if K.is_QQ and query('USE_HEU_GCD'):
try:
return dmp_qq_heu_gcd(f, g, u, K)
except HeuristicGCDFailed:
pass
return dmp_ff_prs_gcd(f, g, u, K)
else:
if K.is_ZZ and query('USE_HEU_GCD'):
try:
return dmp_zz_heu_gcd(f, g, u, K)
except HeuristicGCDFailed:
pass
return dmp_rr_prs_gcd(f, g, u, K)
def dmp_inner_gcd(f, g, u, K):
"""
Computes polynomial GCD and cofactors of `f` and `g` in `K[X]`.
Returns ``(h, cff, cfg)`` such that ``a = gcd(f, g)``,
``cff = quo(f, h)``, and ``cfg = quo(g, h)``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y, = ring("x,y", ZZ)
>>> f = x**2 + 2*x*y + y**2
>>> g = x**2 + x*y
>>> R.dmp_inner_gcd(f, g)
(x + y, x + y, x)
"""
if not u:
return dup_inner_gcd(f, g, K)
J, (f, g) = dmp_multi_deflate((f, g), u, K)
h, cff, cfg = _dmp_inner_gcd(f, g, u, K)
return (dmp_inflate(h, J, u, K),
dmp_inflate(cff, J, u, K),
dmp_inflate(cfg, J, u, K))
def dup_gcd(f, g, K):
"""
Computes polynomial GCD of `f` and `g` in `K[x]`.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_gcd(x**2 - 1, x**2 - 3*x + 2)
x - 1
"""
return dup_inner_gcd(f, g, K)[0]
def dmp_gcd(f, g, u, K):
"""
Computes polynomial GCD of `f` and `g` in `K[X]`.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y, = ring("x,y", ZZ)
>>> f = x**2 + 2*x*y + y**2
>>> g = x**2 + x*y
>>> R.dmp_gcd(f, g)
x + y
"""
return dmp_inner_gcd(f, g, u, K)[0]
def dup_rr_lcm(f, g, K):
"""
Computes polynomial LCM over a ring in `K[x]`.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_rr_lcm(x**2 - 1, x**2 - 3*x + 2)
x**3 - 2*x**2 - x + 2
"""
if not f or not g:
return dmp_zero(0)
fc, f = dup_primitive(f, K)
gc, g = dup_primitive(g, K)
c = K.lcm(fc, gc)
h = dup_quo(dup_mul(f, g, K),
dup_gcd(f, g, K), K)
u = K.canonical_unit(dup_LC(h, K))
return dup_mul_ground(h, c*u, K)
def dup_ff_lcm(f, g, K):
"""
Computes polynomial LCM over a field in `K[x]`.
Examples
========
>>> from sympy.polys import ring, QQ
>>> R, x = ring("x", QQ)
>>> f = QQ(1,2)*x**2 + QQ(7,4)*x + QQ(3,2)
>>> g = QQ(1,2)*x**2 + x
>>> R.dup_ff_lcm(f, g)
x**3 + 7/2*x**2 + 3*x
"""
h = dup_quo(dup_mul(f, g, K),
dup_gcd(f, g, K), K)
return dup_monic(h, K)
def dup_lcm(f, g, K):
"""
Computes polynomial LCM of `f` and `g` in `K[x]`.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_lcm(x**2 - 1, x**2 - 3*x + 2)
x**3 - 2*x**2 - x + 2
"""
if K.is_Field:
return dup_ff_lcm(f, g, K)
else:
return dup_rr_lcm(f, g, K)
def dmp_rr_lcm(f, g, u, K):
"""
Computes polynomial LCM over a ring in `K[X]`.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y, = ring("x,y", ZZ)
>>> f = x**2 + 2*x*y + y**2
>>> g = x**2 + x*y
>>> R.dmp_rr_lcm(f, g)
x**3 + 2*x**2*y + x*y**2
"""
fc, f = dmp_ground_primitive(f, u, K)
gc, g = dmp_ground_primitive(g, u, K)
c = K.lcm(fc, gc)
h = dmp_quo(dmp_mul(f, g, u, K),
dmp_gcd(f, g, u, K), u, K)
return dmp_mul_ground(h, c, u, K)
def dmp_ff_lcm(f, g, u, K):
"""
Computes polynomial LCM over a field in `K[X]`.
Examples
========
>>> from sympy.polys import ring, QQ
>>> R, x,y, = ring("x,y", QQ)
>>> f = QQ(1,4)*x**2 + x*y + y**2
>>> g = QQ(1,2)*x**2 + x*y
>>> R.dmp_ff_lcm(f, g)
x**3 + 4*x**2*y + 4*x*y**2
"""
h = dmp_quo(dmp_mul(f, g, u, K),
dmp_gcd(f, g, u, K), u, K)
return dmp_ground_monic(h, u, K)
def dmp_lcm(f, g, u, K):
"""
Computes polynomial LCM of `f` and `g` in `K[X]`.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y, = ring("x,y", ZZ)
>>> f = x**2 + 2*x*y + y**2
>>> g = x**2 + x*y
>>> R.dmp_lcm(f, g)
x**3 + 2*x**2*y + x*y**2
"""
if not u:
return dup_lcm(f, g, K)
if K.is_Field:
return dmp_ff_lcm(f, g, u, K)
else:
return dmp_rr_lcm(f, g, u, K)
def dmp_content(f, u, K):
"""
Returns GCD of multivariate coefficients.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y, = ring("x,y", ZZ)
>>> R.dmp_content(2*x*y + 6*x + 4*y + 12)
2*y + 6
"""
cont, v = dmp_LC(f, K), u - 1
if dmp_zero_p(f, u):
return cont
for c in f[1:]:
cont = dmp_gcd(cont, c, v, K)
if dmp_one_p(cont, v, K):
break
if K.is_negative(dmp_ground_LC(cont, v, K)):
return dmp_neg(cont, v, K)
else:
return cont
def dmp_primitive(f, u, K):
"""
Returns multivariate content and a primitive polynomial.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y, = ring("x,y", ZZ)
>>> R.dmp_primitive(2*x*y + 6*x + 4*y + 12)
(2*y + 6, x + 2)
"""
cont, v = dmp_content(f, u, K), u - 1
if dmp_zero_p(f, u) or dmp_one_p(cont, v, K):
return cont, f
else:
return cont, [ dmp_quo(c, cont, v, K) for c in f ]
def dup_cancel(f, g, K, include=True):
"""
Cancel common factors in a rational function `f/g`.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_cancel(2*x**2 - 2, x**2 - 2*x + 1)
(2*x + 2, x - 1)
"""
return dmp_cancel(f, g, 0, K, include=include)
def dmp_cancel(f, g, u, K, include=True):
"""
Cancel common factors in a rational function `f/g`.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dmp_cancel(2*x**2 - 2, x**2 - 2*x + 1)
(2*x + 2, x - 1)
"""
K0 = None
if K.is_Field and K.has_assoc_Ring:
K0, K = K, K.get_ring()
cq, f = dmp_clear_denoms(f, u, K0, K, convert=True)
cp, g = dmp_clear_denoms(g, u, K0, K, convert=True)
else:
cp, cq = K.one, K.one
_, p, q = dmp_inner_gcd(f, g, u, K)
if K0 is not None:
_, cp, cq = K.cofactors(cp, cq)
p = dmp_convert(p, u, K, K0)
q = dmp_convert(q, u, K, K0)
K = K0
p_neg = K.is_negative(dmp_ground_LC(p, u, K))
q_neg = K.is_negative(dmp_ground_LC(q, u, K))
if p_neg and q_neg:
p, q = dmp_neg(p, u, K), dmp_neg(q, u, K)
elif p_neg:
cp, p = -cp, dmp_neg(p, u, K)
elif q_neg:
cp, q = -cp, dmp_neg(q, u, K)
if not include:
return cp, cq, p, q
p = dmp_mul_ground(p, cp, u, K)
q = dmp_mul_ground(q, cq, u, K)
return p, q
PK ]ZZZW��� � sympy/polys/factortools.py"""Polynomial factorization routines in characteristic zero. """
from sympy.external.gmpy import GROUND_TYPES
from sympy.core.random import _randint
from sympy.polys.galoistools import (
gf_from_int_poly, gf_to_int_poly,
gf_lshift, gf_add_mul, gf_mul,
gf_div, gf_rem,
gf_gcdex,
gf_sqf_p,
gf_factor_sqf, gf_factor)
from sympy.polys.densebasic import (
dup_LC, dmp_LC, dmp_ground_LC,
dup_TC,
dup_convert, dmp_convert,
dup_degree, dmp_degree,
dmp_degree_in, dmp_degree_list,
dmp_from_dict,
dmp_zero_p,
dmp_one,
dmp_nest, dmp_raise,
dup_strip,
dmp_ground,
dup_inflate,
dmp_exclude, dmp_include,
dmp_inject, dmp_eject,
dup_terms_gcd, dmp_terms_gcd)
from sympy.polys.densearith import (
dup_neg, dmp_neg,
dup_add, dmp_add,
dup_sub, dmp_sub,
dup_mul, dmp_mul,
dup_sqr,
dmp_pow,
dup_div, dmp_div,
dup_quo, dmp_quo,
dmp_expand,
dmp_add_mul,
dup_sub_mul, dmp_sub_mul,
dup_lshift,
dup_max_norm, dmp_max_norm,
dup_l1_norm,
dup_mul_ground, dmp_mul_ground,
dup_quo_ground, dmp_quo_ground)
from sympy.polys.densetools import (
dup_clear_denoms, dmp_clear_denoms,
dup_trunc, dmp_ground_trunc,
dup_content,
dup_monic, dmp_ground_monic,
dup_primitive, dmp_ground_primitive,
dmp_eval_tail,
dmp_eval_in, dmp_diff_eval_in,
dup_shift, dmp_shift, dup_mirror)
from sympy.polys.euclidtools import (
dmp_primitive,
dup_inner_gcd, dmp_inner_gcd)
from sympy.polys.sqfreetools import (
dup_sqf_p,
dup_sqf_norm, dmp_sqf_norm,
dup_sqf_part, dmp_sqf_part,
_dup_check_degrees, _dmp_check_degrees,
)
from sympy.polys.polyutils import _sort_factors
from sympy.polys.polyconfig import query
from sympy.polys.polyerrors import (
ExtraneousFactors, DomainError, CoercionFailed, EvaluationFailed)
from sympy.utilities import subsets
from math import ceil as _ceil, log as _log, log2 as _log2
if GROUND_TYPES == 'flint':
from flint import fmpz_poly
else:
fmpz_poly = None
def dup_trial_division(f, factors, K):
"""
Determine multiplicities of factors for a univariate polynomial
using trial division.
An error will be raised if any factor does not divide ``f``.
"""
result = []
for factor in factors:
k = 0
while True:
q, r = dup_div(f, factor, K)
if not r:
f, k = q, k + 1
else:
break
if k == 0:
raise RuntimeError("trial division failed")
result.append((factor, k))
return _sort_factors(result)
def dmp_trial_division(f, factors, u, K):
"""
Determine multiplicities of factors for a multivariate polynomial
using trial division.
An error will be raised if any factor does not divide ``f``.
"""
result = []
for factor in factors:
k = 0
while True:
q, r = dmp_div(f, factor, u, K)
if dmp_zero_p(r, u):
f, k = q, k + 1
else:
break
if k == 0:
raise RuntimeError("trial division failed")
result.append((factor, k))
return _sort_factors(result)
def dup_zz_mignotte_bound(f, K):
"""
The Knuth-Cohen variant of Mignotte bound for
univariate polynomials in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> f = x**3 + 14*x**2 + 56*x + 64
>>> R.dup_zz_mignotte_bound(f)
152
By checking ``factor(f)`` we can see that max coeff is 8
Also consider a case that ``f`` is irreducible for example
``f = 2*x**2 + 3*x + 4``. To avoid a bug for these cases, we return the
bound plus the max coefficient of ``f``
>>> f = 2*x**2 + 3*x + 4
>>> R.dup_zz_mignotte_bound(f)
6
Lastly, to see the difference between the new and the old Mignotte bound
consider the irreducible polynomial:
>>> f = 87*x**7 + 4*x**6 + 80*x**5 + 17*x**4 + 9*x**3 + 12*x**2 + 49*x + 26
>>> R.dup_zz_mignotte_bound(f)
744
The new Mignotte bound is 744 whereas the old one (SymPy 1.5.1) is 1937664.
References
==========
..[1] [Abbott13]_
"""
from sympy.functions.combinatorial.factorials import binomial
d = dup_degree(f)
delta = _ceil(d / 2)
delta2 = _ceil(delta / 2)
# euclidean-norm
eucl_norm = K.sqrt( sum( cf**2 for cf in f ) )
# biggest values of binomial coefficients (p. 538 of reference)
t1 = binomial(delta - 1, delta2)
t2 = binomial(delta - 1, delta2 - 1)
lc = K.abs(dup_LC(f, K)) # leading coefficient
bound = t1 * eucl_norm + t2 * lc # (p. 538 of reference)
bound += dup_max_norm(f, K) # add max coeff for irreducible polys
bound = _ceil(bound / 2) * 2 # round up to even integer
return bound
def dmp_zz_mignotte_bound(f, u, K):
"""Mignotte bound for multivariate polynomials in `K[X]`. """
a = dmp_max_norm(f, u, K)
b = abs(dmp_ground_LC(f, u, K))
n = sum(dmp_degree_list(f, u))
return K.sqrt(K(n + 1))*2**n*a*b
def dup_zz_hensel_step(m, f, g, h, s, t, K):
"""
One step in Hensel lifting in `Z[x]`.
Given positive integer `m` and `Z[x]` polynomials `f`, `g`, `h`, `s`
and `t` such that::
f = g*h (mod m)
s*g + t*h = 1 (mod m)
lc(f) is not a zero divisor (mod m)
lc(h) = 1
deg(f) = deg(g) + deg(h)
deg(s) < deg(h)
deg(t) < deg(g)
returns polynomials `G`, `H`, `S` and `T`, such that::
f = G*H (mod m**2)
S*G + T*H = 1 (mod m**2)
References
==========
.. [1] [Gathen99]_
"""
M = m**2
e = dup_sub_mul(f, g, h, K)
e = dup_trunc(e, M, K)
q, r = dup_div(dup_mul(s, e, K), h, K)
q = dup_trunc(q, M, K)
r = dup_trunc(r, M, K)
u = dup_add(dup_mul(t, e, K), dup_mul(q, g, K), K)
G = dup_trunc(dup_add(g, u, K), M, K)
H = dup_trunc(dup_add(h, r, K), M, K)
u = dup_add(dup_mul(s, G, K), dup_mul(t, H, K), K)
b = dup_trunc(dup_sub(u, [K.one], K), M, K)
c, d = dup_div(dup_mul(s, b, K), H, K)
c = dup_trunc(c, M, K)
d = dup_trunc(d, M, K)
u = dup_add(dup_mul(t, b, K), dup_mul(c, G, K), K)
S = dup_trunc(dup_sub(s, d, K), M, K)
T = dup_trunc(dup_sub(t, u, K), M, K)
return G, H, S, T
def dup_zz_hensel_lift(p, f, f_list, l, K):
r"""
Multifactor Hensel lifting in `Z[x]`.
Given a prime `p`, polynomial `f` over `Z[x]` such that `lc(f)`
is a unit modulo `p`, monic pair-wise coprime polynomials `f_i`
over `Z[x]` satisfying::
f = lc(f) f_1 ... f_r (mod p)
and a positive integer `l`, returns a list of monic polynomials
`F_1,\ F_2,\ \dots,\ F_r` satisfying::
f = lc(f) F_1 ... F_r (mod p**l)
F_i = f_i (mod p), i = 1..r
References
==========
.. [1] [Gathen99]_
"""
r = len(f_list)
lc = dup_LC(f, K)
if r == 1:
F = dup_mul_ground(f, K.gcdex(lc, p**l)[0], K)
return [ dup_trunc(F, p**l, K) ]
m = p
k = r // 2
d = int(_ceil(_log2(l)))
g = gf_from_int_poly([lc], p)
for f_i in f_list[:k]:
g = gf_mul(g, gf_from_int_poly(f_i, p), p, K)
h = gf_from_int_poly(f_list[k], p)
for f_i in f_list[k + 1:]:
h = gf_mul(h, gf_from_int_poly(f_i, p), p, K)
s, t, _ = gf_gcdex(g, h, p, K)
g = gf_to_int_poly(g, p)
h = gf_to_int_poly(h, p)
s = gf_to_int_poly(s, p)
t = gf_to_int_poly(t, p)
for _ in range(1, d + 1):
(g, h, s, t), m = dup_zz_hensel_step(m, f, g, h, s, t, K), m**2
return dup_zz_hensel_lift(p, g, f_list[:k], l, K) \
+ dup_zz_hensel_lift(p, h, f_list[k:], l, K)
def _test_pl(fc, q, pl):
if q > pl // 2:
q = q - pl
if not q:
return True
return fc % q == 0
def dup_zz_zassenhaus(f, K):
"""Factor primitive square-free polynomials in `Z[x]`. """
n = dup_degree(f)
if n == 1:
return [f]
from sympy.ntheory import isprime
fc = f[-1]
A = dup_max_norm(f, K)
b = dup_LC(f, K)
B = int(abs(K.sqrt(K(n + 1))*2**n*A*b))
C = int((n + 1)**(2*n)*A**(2*n - 1))
gamma = int(_ceil(2*_log2(C)))
bound = int(2*gamma*_log(gamma))
a = []
# choose a prime number `p` such that `f` be square free in Z_p
# if there are many factors in Z_p, choose among a few different `p`
# the one with fewer factors
for px in range(3, bound + 1):
if not isprime(px) or b % px == 0:
continue
px = K.convert(px)
F = gf_from_int_poly(f, px)
if not gf_sqf_p(F, px, K):
continue
fsqfx = gf_factor_sqf(F, px, K)[1]
a.append((px, fsqfx))
if len(fsqfx) < 15 or len(a) > 4:
break
p, fsqf = min(a, key=lambda x: len(x[1]))
l = int(_ceil(_log(2*B + 1, p)))
modular = [gf_to_int_poly(ff, p) for ff in fsqf]
g = dup_zz_hensel_lift(p, f, modular, l, K)
sorted_T = range(len(g))
T = set(sorted_T)
factors, s = [], 1
pl = p**l
while 2*s <= len(T):
for S in subsets(sorted_T, s):
# lift the constant coefficient of the product `G` of the factors
# in the subset `S`; if it is does not divide `fc`, `G` does
# not divide the input polynomial
if b == 1:
q = 1
for i in S:
q = q*g[i][-1]
q = q % pl
if not _test_pl(fc, q, pl):
continue
else:
G = [b]
for i in S:
G = dup_mul(G, g[i], K)
G = dup_trunc(G, pl, K)
G = dup_primitive(G, K)[1]
q = G[-1]
if q and fc % q != 0:
continue
H = [b]
S = set(S)
T_S = T - S
if b == 1:
G = [b]
for i in S:
G = dup_mul(G, g[i], K)
G = dup_trunc(G, pl, K)
for i in T_S:
H = dup_mul(H, g[i], K)
H = dup_trunc(H, pl, K)
G_norm = dup_l1_norm(G, K)
H_norm = dup_l1_norm(H, K)
if G_norm*H_norm <= B:
T = T_S
sorted_T = [i for i in sorted_T if i not in S]
G = dup_primitive(G, K)[1]
f = dup_primitive(H, K)[1]
factors.append(G)
b = dup_LC(f, K)
break
else:
s += 1
return factors + [f]
def dup_zz_irreducible_p(f, K):
"""Test irreducibility using Eisenstein's criterion. """
lc = dup_LC(f, K)
tc = dup_TC(f, K)
e_fc = dup_content(f[1:], K)
if e_fc:
from sympy.ntheory import factorint
e_ff = factorint(int(e_fc))
for p in e_ff.keys():
if (lc % p) and (tc % p**2):
return True
def dup_cyclotomic_p(f, K, irreducible=False):
"""
Efficiently test if ``f`` is a cyclotomic polynomial.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> f = x**16 + x**14 - x**10 + x**8 - x**6 + x**2 + 1
>>> R.dup_cyclotomic_p(f)
False
>>> g = x**16 + x**14 - x**10 - x**8 - x**6 + x**2 + 1
>>> R.dup_cyclotomic_p(g)
True
References
==========
Bradford, Russell J., and James H. Davenport. "Effective tests for
cyclotomic polynomials." In International Symposium on Symbolic and
Algebraic Computation, pp. 244-251. Springer, Berlin, Heidelberg, 1988.
"""
if K.is_QQ:
try:
K0, K = K, K.get_ring()
f = dup_convert(f, K0, K)
except CoercionFailed:
return False
elif not K.is_ZZ:
return False
lc = dup_LC(f, K)
tc = dup_TC(f, K)
if lc != 1 or (tc != -1 and tc != 1):
return False
if not irreducible:
coeff, factors = dup_factor_list(f, K)
if coeff != K.one or factors != [(f, 1)]:
return False
n = dup_degree(f)
g, h = [], []
for i in range(n, -1, -2):
g.insert(0, f[i])
for i in range(n - 1, -1, -2):
h.insert(0, f[i])
g = dup_sqr(dup_strip(g), K)
h = dup_sqr(dup_strip(h), K)
F = dup_sub(g, dup_lshift(h, 1, K), K)
if K.is_negative(dup_LC(F, K)):
F = dup_neg(F, K)
if F == f:
return True
g = dup_mirror(f, K)
if K.is_negative(dup_LC(g, K)):
g = dup_neg(g, K)
if F == g and dup_cyclotomic_p(g, K):
return True
G = dup_sqf_part(F, K)
if dup_sqr(G, K) == F and dup_cyclotomic_p(G, K):
return True
return False
def dup_zz_cyclotomic_poly(n, K):
"""Efficiently generate n-th cyclotomic polynomial. """
from sympy.ntheory import factorint
h = [K.one, -K.one]
for p, k in factorint(n).items():
h = dup_quo(dup_inflate(h, p, K), h, K)
h = dup_inflate(h, p**(k - 1), K)
return h
def _dup_cyclotomic_decompose(n, K):
from sympy.ntheory import factorint
H = [[K.one, -K.one]]
for p, k in factorint(n).items():
Q = [ dup_quo(dup_inflate(h, p, K), h, K) for h in H ]
H.extend(Q)
for i in range(1, k):
Q = [ dup_inflate(q, p, K) for q in Q ]
H.extend(Q)
return H
def dup_zz_cyclotomic_factor(f, K):
"""
Efficiently factor polynomials `x**n - 1` and `x**n + 1` in `Z[x]`.
Given a univariate polynomial `f` in `Z[x]` returns a list of factors
of `f`, provided that `f` is in the form `x**n - 1` or `x**n + 1` for
`n >= 1`. Otherwise returns None.
Factorization is performed using cyclotomic decomposition of `f`,
which makes this method much faster that any other direct factorization
approach (e.g. Zassenhaus's).
References
==========
.. [1] [Weisstein09]_
"""
lc_f, tc_f = dup_LC(f, K), dup_TC(f, K)
if dup_degree(f) <= 0:
return None
if lc_f != 1 or tc_f not in [-1, 1]:
return None
if any(bool(cf) for cf in f[1:-1]):
return None
n = dup_degree(f)
F = _dup_cyclotomic_decompose(n, K)
if not K.is_one(tc_f):
return F
else:
H = []
for h in _dup_cyclotomic_decompose(2*n, K):
if h not in F:
H.append(h)
return H
def dup_zz_factor_sqf(f, K):
"""Factor square-free (non-primitive) polynomials in `Z[x]`. """
cont, g = dup_primitive(f, K)
n = dup_degree(g)
if dup_LC(g, K) < 0:
cont, g = -cont, dup_neg(g, K)
if n <= 0:
return cont, []
elif n == 1:
return cont, [g]
if query('USE_IRREDUCIBLE_IN_FACTOR'):
if dup_zz_irreducible_p(g, K):
return cont, [g]
factors = None
if query('USE_CYCLOTOMIC_FACTOR'):
factors = dup_zz_cyclotomic_factor(g, K)
if factors is None:
factors = dup_zz_zassenhaus(g, K)
return cont, _sort_factors(factors, multiple=False)
def dup_zz_factor(f, K):
"""
Factor (non square-free) polynomials in `Z[x]`.
Given a univariate polynomial `f` in `Z[x]` computes its complete
factorization `f_1, ..., f_n` into irreducibles over integers::
f = content(f) f_1**k_1 ... f_n**k_n
The factorization is computed by reducing the input polynomial
into a primitive square-free polynomial and factoring it using
Zassenhaus algorithm. Trial division is used to recover the
multiplicities of factors.
The result is returned as a tuple consisting of::
(content(f), [(f_1, k_1), ..., (f_n, k_n))
Examples
========
Consider the polynomial `f = 2*x**4 - 2`::
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_zz_factor(2*x**4 - 2)
(2, [(x - 1, 1), (x + 1, 1), (x**2 + 1, 1)])
In result we got the following factorization::
f = 2 (x - 1) (x + 1) (x**2 + 1)
Note that this is a complete factorization over integers,
however over Gaussian integers we can factor the last term.
By default, polynomials `x**n - 1` and `x**n + 1` are factored
using cyclotomic decomposition to speedup computations. To
disable this behaviour set cyclotomic=False.
References
==========
.. [1] [Gathen99]_
"""
if GROUND_TYPES == 'flint':
f_flint = fmpz_poly(f[::-1])
cont, factors = f_flint.factor()
factors = [(fac.coeffs()[::-1], exp) for fac, exp in factors]
return cont, _sort_factors(factors)
cont, g = dup_primitive(f, K)
n = dup_degree(g)
if dup_LC(g, K) < 0:
cont, g = -cont, dup_neg(g, K)
if n <= 0:
return cont, []
elif n == 1:
return cont, [(g, 1)]
if query('USE_IRREDUCIBLE_IN_FACTOR'):
if dup_zz_irreducible_p(g, K):
return cont, [(g, 1)]
g = dup_sqf_part(g, K)
H = None
if query('USE_CYCLOTOMIC_FACTOR'):
H = dup_zz_cyclotomic_factor(g, K)
if H is None:
H = dup_zz_zassenhaus(g, K)
factors = dup_trial_division(f, H, K)
_dup_check_degrees(f, factors)
return cont, factors
def dmp_zz_wang_non_divisors(E, cs, ct, K):
"""Wang/EEZ: Compute a set of valid divisors. """
result = [ cs*ct ]
for q in E:
q = abs(q)
for r in reversed(result):
while r != 1:
r = K.gcd(r, q)
q = q // r
if K.is_one(q):
return None
result.append(q)
return result[1:]
def dmp_zz_wang_test_points(f, T, ct, A, u, K):
"""Wang/EEZ: Test evaluation points for suitability. """
if not dmp_eval_tail(dmp_LC(f, K), A, u - 1, K):
raise EvaluationFailed('no luck')
g = dmp_eval_tail(f, A, u, K)
if not dup_sqf_p(g, K):
raise EvaluationFailed('no luck')
c, h = dup_primitive(g, K)
if K.is_negative(dup_LC(h, K)):
c, h = -c, dup_neg(h, K)
v = u - 1
E = [ dmp_eval_tail(t, A, v, K) for t, _ in T ]
D = dmp_zz_wang_non_divisors(E, c, ct, K)
if D is not None:
return c, h, E
else:
raise EvaluationFailed('no luck')
def dmp_zz_wang_lead_coeffs(f, T, cs, E, H, A, u, K):
"""Wang/EEZ: Compute correct leading coefficients. """
C, J, v = [], [0]*len(E), u - 1
for h in H:
c = dmp_one(v, K)
d = dup_LC(h, K)*cs
for i in reversed(range(len(E))):
k, e, (t, _) = 0, E[i], T[i]
while not (d % e):
d, k = d//e, k + 1
if k != 0:
c, J[i] = dmp_mul(c, dmp_pow(t, k, v, K), v, K), 1
C.append(c)
if not all(J):
raise ExtraneousFactors # pragma: no cover
CC, HH = [], []
for c, h in zip(C, H):
d = dmp_eval_tail(c, A, v, K)
lc = dup_LC(h, K)
if K.is_one(cs):
cc = lc//d
else:
g = K.gcd(lc, d)
d, cc = d//g, lc//g
h, cs = dup_mul_ground(h, d, K), cs//d
c = dmp_mul_ground(c, cc, v, K)
CC.append(c)
HH.append(h)
if K.is_one(cs):
return f, HH, CC
CCC, HHH = [], []
for c, h in zip(CC, HH):
CCC.append(dmp_mul_ground(c, cs, v, K))
HHH.append(dmp_mul_ground(h, cs, 0, K))
f = dmp_mul_ground(f, cs**(len(H) - 1), u, K)
return f, HHH, CCC
def dup_zz_diophantine(F, m, p, K):
"""Wang/EEZ: Solve univariate Diophantine equations. """
if len(F) == 2:
a, b = F
f = gf_from_int_poly(a, p)
g = gf_from_int_poly(b, p)
s, t, G = gf_gcdex(g, f, p, K)
s = gf_lshift(s, m, K)
t = gf_lshift(t, m, K)
q, s = gf_div(s, f, p, K)
t = gf_add_mul(t, q, g, p, K)
s = gf_to_int_poly(s, p)
t = gf_to_int_poly(t, p)
result = [s, t]
else:
G = [F[-1]]
for f in reversed(F[1:-1]):
G.insert(0, dup_mul(f, G[0], K))
S, T = [], [[1]]
for f, g in zip(F, G):
t, s = dmp_zz_diophantine([g, f], T[-1], [], 0, p, 1, K)
T.append(t)
S.append(s)
result, S = [], S + [T[-1]]
for s, f in zip(S, F):
s = gf_from_int_poly(s, p)
f = gf_from_int_poly(f, p)
r = gf_rem(gf_lshift(s, m, K), f, p, K)
s = gf_to_int_poly(r, p)
result.append(s)
return result
def dmp_zz_diophantine(F, c, A, d, p, u, K):
"""Wang/EEZ: Solve multivariate Diophantine equations. """
if not A:
S = [ [] for _ in F ]
n = dup_degree(c)
for i, coeff in enumerate(c):
if not coeff:
continue
T = dup_zz_diophantine(F, n - i, p, K)
for j, (s, t) in enumerate(zip(S, T)):
t = dup_mul_ground(t, coeff, K)
S[j] = dup_trunc(dup_add(s, t, K), p, K)
else:
n = len(A)
e = dmp_expand(F, u, K)
a, A = A[-1], A[:-1]
B, G = [], []
for f in F:
B.append(dmp_quo(e, f, u, K))
G.append(dmp_eval_in(f, a, n, u, K))
C = dmp_eval_in(c, a, n, u, K)
v = u - 1
S = dmp_zz_diophantine(G, C, A, d, p, v, K)
S = [ dmp_raise(s, 1, v, K) for s in S ]
for s, b in zip(S, B):
c = dmp_sub_mul(c, s, b, u, K)
c = dmp_ground_trunc(c, p, u, K)
m = dmp_nest([K.one, -a], n, K)
M = dmp_one(n, K)
for k in range(0, d):
if dmp_zero_p(c, u):
break
M = dmp_mul(M, m, u, K)
C = dmp_diff_eval_in(c, k + 1, a, n, u, K)
if not dmp_zero_p(C, v):
C = dmp_quo_ground(C, K.factorial(K(k) + 1), v, K)
T = dmp_zz_diophantine(G, C, A, d, p, v, K)
for i, t in enumerate(T):
T[i] = dmp_mul(dmp_raise(t, 1, v, K), M, u, K)
for i, (s, t) in enumerate(zip(S, T)):
S[i] = dmp_add(s, t, u, K)
for t, b in zip(T, B):
c = dmp_sub_mul(c, t, b, u, K)
c = dmp_ground_trunc(c, p, u, K)
S = [ dmp_ground_trunc(s, p, u, K) for s in S ]
return S
def dmp_zz_wang_hensel_lifting(f, H, LC, A, p, u, K):
"""Wang/EEZ: Parallel Hensel lifting algorithm. """
S, n, v = [f], len(A), u - 1
H = list(H)
for i, a in enumerate(reversed(A[1:])):
s = dmp_eval_in(S[0], a, n - i, u - i, K)
S.insert(0, dmp_ground_trunc(s, p, v - i, K))
d = max(dmp_degree_list(f, u)[1:])
for j, s, a in zip(range(2, n + 2), S, A):
G, w = list(H), j - 1
I, J = A[:j - 2], A[j - 1:]
for i, (h, lc) in enumerate(zip(H, LC)):
lc = dmp_ground_trunc(dmp_eval_tail(lc, J, v, K), p, w - 1, K)
H[i] = [lc] + dmp_raise(h[1:], 1, w - 1, K)
m = dmp_nest([K.one, -a], w, K)
M = dmp_one(w, K)
c = dmp_sub(s, dmp_expand(H, w, K), w, K)
dj = dmp_degree_in(s, w, w)
for k in range(0, dj):
if dmp_zero_p(c, w):
break
M = dmp_mul(M, m, w, K)
C = dmp_diff_eval_in(c, k + 1, a, w, w, K)
if not dmp_zero_p(C, w - 1):
C = dmp_quo_ground(C, K.factorial(K(k) + 1), w - 1, K)
T = dmp_zz_diophantine(G, C, I, d, p, w - 1, K)
for i, (h, t) in enumerate(zip(H, T)):
h = dmp_add_mul(h, dmp_raise(t, 1, w - 1, K), M, w, K)
H[i] = dmp_ground_trunc(h, p, w, K)
h = dmp_sub(s, dmp_expand(H, w, K), w, K)
c = dmp_ground_trunc(h, p, w, K)
if dmp_expand(H, u, K) != f:
raise ExtraneousFactors # pragma: no cover
else:
return H
def dmp_zz_wang(f, u, K, mod=None, seed=None):
r"""
Factor primitive square-free polynomials in `Z[X]`.
Given a multivariate polynomial `f` in `Z[x_1,...,x_n]`, which is
primitive and square-free in `x_1`, computes factorization of `f` into
irreducibles over integers.
The procedure is based on Wang's Enhanced Extended Zassenhaus
algorithm. The algorithm works by viewing `f` as a univariate polynomial
in `Z[x_2,...,x_n][x_1]`, for which an evaluation mapping is computed::
x_2 -> a_2, ..., x_n -> a_n
where `a_i`, for `i = 2, \dots, n`, are carefully chosen integers. The
mapping is used to transform `f` into a univariate polynomial in `Z[x_1]`,
which can be factored efficiently using Zassenhaus algorithm. The last
step is to lift univariate factors to obtain true multivariate
factors. For this purpose a parallel Hensel lifting procedure is used.
The parameter ``seed`` is passed to _randint and can be used to seed randint
(when an integer) or (for testing purposes) can be a sequence of numbers.
References
==========
.. [1] [Wang78]_
.. [2] [Geddes92]_
"""
from sympy.ntheory import nextprime
randint = _randint(seed)
ct, T = dmp_zz_factor(dmp_LC(f, K), u - 1, K)
b = dmp_zz_mignotte_bound(f, u, K)
p = K(nextprime(b))
if mod is None:
if u == 1:
mod = 2
else:
mod = 1
history, configs, A, r = set(), [], [K.zero]*u, None
try:
cs, s, E = dmp_zz_wang_test_points(f, T, ct, A, u, K)
_, H = dup_zz_factor_sqf(s, K)
r = len(H)
if r == 1:
return [f]
configs = [(s, cs, E, H, A)]
except EvaluationFailed:
pass
eez_num_configs = query('EEZ_NUMBER_OF_CONFIGS')
eez_num_tries = query('EEZ_NUMBER_OF_TRIES')
eez_mod_step = query('EEZ_MODULUS_STEP')
while len(configs) < eez_num_configs:
for _ in range(eez_num_tries):
A = [ K(randint(-mod, mod)) for _ in range(u) ]
if tuple(A) not in history:
history.add(tuple(A))
else:
continue
try:
cs, s, E = dmp_zz_wang_test_points(f, T, ct, A, u, K)
except EvaluationFailed:
continue
_, H = dup_zz_factor_sqf(s, K)
rr = len(H)
if r is not None:
if rr != r: # pragma: no cover
if rr < r:
configs, r = [], rr
else:
continue
else:
r = rr
if r == 1:
return [f]
configs.append((s, cs, E, H, A))
if len(configs) == eez_num_configs:
break
else:
mod += eez_mod_step
s_norm, s_arg, i = None, 0, 0
for s, _, _, _, _ in configs:
_s_norm = dup_max_norm(s, K)
if s_norm is not None:
if _s_norm < s_norm:
s_norm = _s_norm
s_arg = i
else:
s_norm = _s_norm
i += 1
_, cs, E, H, A = configs[s_arg]
orig_f = f
try:
f, H, LC = dmp_zz_wang_lead_coeffs(f, T, cs, E, H, A, u, K)
factors = dmp_zz_wang_hensel_lifting(f, H, LC, A, p, u, K)
except ExtraneousFactors: # pragma: no cover
if query('EEZ_RESTART_IF_NEEDED'):
return dmp_zz_wang(orig_f, u, K, mod + 1)
else:
raise ExtraneousFactors(
"we need to restart algorithm with better parameters")
result = []
for f in factors:
_, f = dmp_ground_primitive(f, u, K)
if K.is_negative(dmp_ground_LC(f, u, K)):
f = dmp_neg(f, u, K)
result.append(f)
return result
def dmp_zz_factor(f, u, K):
r"""
Factor (non square-free) polynomials in `Z[X]`.
Given a multivariate polynomial `f` in `Z[x]` computes its complete
factorization `f_1, \dots, f_n` into irreducibles over integers::
f = content(f) f_1**k_1 ... f_n**k_n
The factorization is computed by reducing the input polynomial
into a primitive square-free polynomial and factoring it using
Enhanced Extended Zassenhaus (EEZ) algorithm. Trial division
is used to recover the multiplicities of factors.
The result is returned as a tuple consisting of::
(content(f), [(f_1, k_1), ..., (f_n, k_n))
Consider polynomial `f = 2*(x**2 - y**2)`::
>>> from sympy.polys import ring, ZZ
>>> R, x,y = ring("x,y", ZZ)
>>> R.dmp_zz_factor(2*x**2 - 2*y**2)
(2, [(x - y, 1), (x + y, 1)])
In result we got the following factorization::
f = 2 (x - y) (x + y)
References
==========
.. [1] [Gathen99]_
"""
if not u:
return dup_zz_factor(f, K)
if dmp_zero_p(f, u):
return K.zero, []
cont, g = dmp_ground_primitive(f, u, K)
if dmp_ground_LC(g, u, K) < 0:
cont, g = -cont, dmp_neg(g, u, K)
if all(d <= 0 for d in dmp_degree_list(g, u)):
return cont, []
G, g = dmp_primitive(g, u, K)
factors = []
if dmp_degree(g, u) > 0:
g = dmp_sqf_part(g, u, K)
H = dmp_zz_wang(g, u, K)
factors = dmp_trial_division(f, H, u, K)
for g, k in dmp_zz_factor(G, u - 1, K)[1]:
factors.insert(0, ([g], k))
_dmp_check_degrees(f, u, factors)
return cont, _sort_factors(factors)
def dup_qq_i_factor(f, K0):
"""Factor univariate polynomials into irreducibles in `QQ_I[x]`. """
# Factor in QQ<I>
K1 = K0.as_AlgebraicField()
f = dup_convert(f, K0, K1)
coeff, factors = dup_factor_list(f, K1)
factors = [(dup_convert(fac, K1, K0), i) for fac, i in factors]
coeff = K0.convert(coeff, K1)
return coeff, factors
def dup_zz_i_factor(f, K0):
"""Factor univariate polynomials into irreducibles in `ZZ_I[x]`. """
# First factor in QQ_I
K1 = K0.get_field()
f = dup_convert(f, K0, K1)
coeff, factors = dup_qq_i_factor(f, K1)
new_factors = []
for fac, i in factors:
# Extract content
fac_denom, fac_num = dup_clear_denoms(fac, K1)
fac_num_ZZ_I = dup_convert(fac_num, K1, K0)
content, fac_prim = dmp_ground_primitive(fac_num_ZZ_I, 0, K0)
coeff = (coeff * content ** i) // fac_denom ** i
new_factors.append((fac_prim, i))
factors = new_factors
coeff = K0.convert(coeff, K1)
return coeff, factors
def dmp_qq_i_factor(f, u, K0):
"""Factor multivariate polynomials into irreducibles in `QQ_I[X]`. """
# Factor in QQ<I>
K1 = K0.as_AlgebraicField()
f = dmp_convert(f, u, K0, K1)
coeff, factors = dmp_factor_list(f, u, K1)
factors = [(dmp_convert(fac, u, K1, K0), i) for fac, i in factors]
coeff = K0.convert(coeff, K1)
return coeff, factors
def dmp_zz_i_factor(f, u, K0):
"""Factor multivariate polynomials into irreducibles in `ZZ_I[X]`. """
# First factor in QQ_I
K1 = K0.get_field()
f = dmp_convert(f, u, K0, K1)
coeff, factors = dmp_qq_i_factor(f, u, K1)
new_factors = []
for fac, i in factors:
# Extract content
fac_denom, fac_num = dmp_clear_denoms(fac, u, K1)
fac_num_ZZ_I = dmp_convert(fac_num, u, K1, K0)
content, fac_prim = dmp_ground_primitive(fac_num_ZZ_I, u, K0)
coeff = (coeff * content ** i) // fac_denom ** i
new_factors.append((fac_prim, i))
factors = new_factors
coeff = K0.convert(coeff, K1)
return coeff, factors
def dup_ext_factor(f, K):
r"""Factor univariate polynomials over algebraic number fields.
The domain `K` must be an algebraic number field `k(a)` (see :ref:`QQ(a)`).
Examples
========
First define the algebraic number field `K = \mathbb{Q}(\sqrt{2})`:
>>> from sympy import QQ, sqrt
>>> from sympy.polys.factortools import dup_ext_factor
>>> K = QQ.algebraic_field(sqrt(2))
We can now factorise the polynomial `x^2 - 2` over `K`:
>>> p = [K(1), K(0), K(-2)] # x^2 - 2
>>> p1 = [K(1), -K.unit] # x - sqrt(2)
>>> p2 = [K(1), +K.unit] # x + sqrt(2)
>>> dup_ext_factor(p, K) == (K.one, [(p1, 1), (p2, 1)])
True
Usually this would be done at a higher level:
>>> from sympy import factor
>>> from sympy.abc import x
>>> factor(x**2 - 2, extension=sqrt(2))
(x - sqrt(2))*(x + sqrt(2))
Explanation
===========
Uses Trager's algorithm. In particular this function is algorithm
``alg_factor`` from [Trager76]_.
If `f` is a polynomial in `k(a)[x]` then its norm `g(x)` is a polynomial in
`k[x]`. If `g(x)` is square-free and has irreducible factors `g_1(x)`,
`g_2(x)`, `\cdots` then the irreducible factors of `f` in `k(a)[x]` are
given by `f_i(x) = \gcd(f(x), g_i(x))` where the GCD is computed in
`k(a)[x]`.
The first step in Trager's algorithm is to find an integer shift `s` so
that `f(x-sa)` has square-free norm. Then the norm is factorized in `k[x]`
and the GCD of (shifted) `f` with each factor gives the shifted factors of
`f`. At the end the shift is undone to recover the unshifted factors of `f`
in `k(a)[x]`.
The algorithm reduces the problem of factorization in `k(a)[x]` to
factorization in `k[x]` with the main additional steps being to compute the
norm (a resultant calculation in `k[x,y]`) and some polynomial GCDs in
`k(a)[x]`.
In practice in SymPy the base field `k` will be the rationals :ref:`QQ` and
this function factorizes a polynomial with coefficients in an algebraic
number field like `\mathbb{Q}(\sqrt{2})`.
See Also
========
dmp_ext_factor:
Analogous function for multivariate polynomials over ``k(a)``.
dup_sqf_norm:
Subroutine ``sqfr_norm`` also from [Trager76]_.
sympy.polys.polytools.factor:
The high-level function that ultimately uses this function as needed.
"""
n, lc = dup_degree(f), dup_LC(f, K)
f = dup_monic(f, K)
if n <= 0:
return lc, []
if n == 1:
return lc, [(f, 1)]
f, F = dup_sqf_part(f, K), f
s, g, r = dup_sqf_norm(f, K)
factors = dup_factor_list_include(r, K.dom)
if len(factors) == 1:
return lc, [(f, n//dup_degree(f))]
H = s*K.unit
for i, (factor, _) in enumerate(factors):
h = dup_convert(factor, K.dom, K)
h, _, g = dup_inner_gcd(h, g, K)
h = dup_shift(h, H, K)
factors[i] = h
factors = dup_trial_division(F, factors, K)
_dup_check_degrees(F, factors)
return lc, factors
def dmp_ext_factor(f, u, K):
r"""Factor multivariate polynomials over algebraic number fields.
The domain `K` must be an algebraic number field `k(a)` (see :ref:`QQ(a)`).
Examples
========
First define the algebraic number field `K = \mathbb{Q}(\sqrt{2})`:
>>> from sympy import QQ, sqrt
>>> from sympy.polys.factortools import dmp_ext_factor
>>> K = QQ.algebraic_field(sqrt(2))
We can now factorise the polynomial `x^2 y^2 - 2` over `K`:
>>> p = [[K(1),K(0),K(0)], [], [K(-2)]] # x**2*y**2 - 2
>>> p1 = [[K(1),K(0)], [-K.unit]] # x*y - sqrt(2)
>>> p2 = [[K(1),K(0)], [+K.unit]] # x*y + sqrt(2)
>>> dmp_ext_factor(p, 1, K) == (K.one, [(p1, 1), (p2, 1)])
True
Usually this would be done at a higher level:
>>> from sympy import factor
>>> from sympy.abc import x, y
>>> factor(x**2*y**2 - 2, extension=sqrt(2))
(x*y - sqrt(2))*(x*y + sqrt(2))
Explanation
===========
This is Trager's algorithm for multivariate polynomials. In particular this
function is algorithm ``alg_factor`` from [Trager76]_.
See :func:`dup_ext_factor` for explanation.
See Also
========
dup_ext_factor:
Analogous function for univariate polynomials over ``k(a)``.
dmp_sqf_norm:
Multivariate version of subroutine ``sqfr_norm`` also from [Trager76]_.
sympy.polys.polytools.factor:
The high-level function that ultimately uses this function as needed.
"""
if not u:
return dup_ext_factor(f, K)
lc = dmp_ground_LC(f, u, K)
f = dmp_ground_monic(f, u, K)
if all(d <= 0 for d in dmp_degree_list(f, u)):
return lc, []
f, F = dmp_sqf_part(f, u, K), f
s, g, r = dmp_sqf_norm(f, u, K)
factors = dmp_factor_list_include(r, u, K.dom)
if len(factors) == 1:
factors = [f]
else:
for i, (factor, _) in enumerate(factors):
h = dmp_convert(factor, u, K.dom, K)
h, _, g = dmp_inner_gcd(h, g, u, K)
a = [si*K.unit for si in s]
h = dmp_shift(h, a, u, K)
factors[i] = h
result = dmp_trial_division(F, factors, u, K)
_dmp_check_degrees(F, u, result)
return lc, result
def dup_gf_factor(f, K):
"""Factor univariate polynomials over finite fields. """
f = dup_convert(f, K, K.dom)
coeff, factors = gf_factor(f, K.mod, K.dom)
for i, (f, k) in enumerate(factors):
factors[i] = (dup_convert(f, K.dom, K), k)
return K.convert(coeff, K.dom), factors
def dmp_gf_factor(f, u, K):
"""Factor multivariate polynomials over finite fields. """
raise NotImplementedError('multivariate polynomials over finite fields')
def dup_factor_list(f, K0):
"""Factor univariate polynomials into irreducibles in `K[x]`. """
j, f = dup_terms_gcd(f, K0)
cont, f = dup_primitive(f, K0)
if K0.is_FiniteField:
coeff, factors = dup_gf_factor(f, K0)
elif K0.is_Algebraic:
coeff, factors = dup_ext_factor(f, K0)
elif K0.is_GaussianRing:
coeff, factors = dup_zz_i_factor(f, K0)
elif K0.is_GaussianField:
coeff, factors = dup_qq_i_factor(f, K0)
else:
if not K0.is_Exact:
K0_inexact, K0 = K0, K0.get_exact()
f = dup_convert(f, K0_inexact, K0)
else:
K0_inexact = None
if K0.is_Field:
K = K0.get_ring()
denom, f = dup_clear_denoms(f, K0, K)
f = dup_convert(f, K0, K)
else:
K = K0
if K.is_ZZ:
coeff, factors = dup_zz_factor(f, K)
elif K.is_Poly:
f, u = dmp_inject(f, 0, K)
coeff, factors = dmp_factor_list(f, u, K.dom)
for i, (f, k) in enumerate(factors):
factors[i] = (dmp_eject(f, u, K), k)
coeff = K.convert(coeff, K.dom)
else: # pragma: no cover
raise DomainError('factorization not supported over %s' % K0)
if K0.is_Field:
for i, (f, k) in enumerate(factors):
factors[i] = (dup_convert(f, K, K0), k)
coeff = K0.convert(coeff, K)
coeff = K0.quo(coeff, denom)
if K0_inexact:
for i, (f, k) in enumerate(factors):
max_norm = dup_max_norm(f, K0)
f = dup_quo_ground(f, max_norm, K0)
f = dup_convert(f, K0, K0_inexact)
factors[i] = (f, k)
coeff = K0.mul(coeff, K0.pow(max_norm, k))
coeff = K0_inexact.convert(coeff, K0)
K0 = K0_inexact
if j:
factors.insert(0, ([K0.one, K0.zero], j))
return coeff*cont, _sort_factors(factors)
def dup_factor_list_include(f, K):
"""Factor univariate polynomials into irreducibles in `K[x]`. """
coeff, factors = dup_factor_list(f, K)
if not factors:
return [(dup_strip([coeff]), 1)]
else:
g = dup_mul_ground(factors[0][0], coeff, K)
return [(g, factors[0][1])] + factors[1:]
def dmp_factor_list(f, u, K0):
"""Factor multivariate polynomials into irreducibles in `K[X]`. """
if not u:
return dup_factor_list(f, K0)
J, f = dmp_terms_gcd(f, u, K0)
cont, f = dmp_ground_primitive(f, u, K0)
if K0.is_FiniteField: # pragma: no cover
coeff, factors = dmp_gf_factor(f, u, K0)
elif K0.is_Algebraic:
coeff, factors = dmp_ext_factor(f, u, K0)
elif K0.is_GaussianRing:
coeff, factors = dmp_zz_i_factor(f, u, K0)
elif K0.is_GaussianField:
coeff, factors = dmp_qq_i_factor(f, u, K0)
else:
if not K0.is_Exact:
K0_inexact, K0 = K0, K0.get_exact()
f = dmp_convert(f, u, K0_inexact, K0)
else:
K0_inexact = None
if K0.is_Field:
K = K0.get_ring()
denom, f = dmp_clear_denoms(f, u, K0, K)
f = dmp_convert(f, u, K0, K)
else:
K = K0
if K.is_ZZ:
levels, f, v = dmp_exclude(f, u, K)
coeff, factors = dmp_zz_factor(f, v, K)
for i, (f, k) in enumerate(factors):
factors[i] = (dmp_include(f, levels, v, K), k)
elif K.is_Poly:
f, v = dmp_inject(f, u, K)
coeff, factors = dmp_factor_list(f, v, K.dom)
for i, (f, k) in enumerate(factors):
factors[i] = (dmp_eject(f, v, K), k)
coeff = K.convert(coeff, K.dom)
else: # pragma: no cover
raise DomainError('factorization not supported over %s' % K0)
if K0.is_Field:
for i, (f, k) in enumerate(factors):
factors[i] = (dmp_convert(f, u, K, K0), k)
coeff = K0.convert(coeff, K)
coeff = K0.quo(coeff, denom)
if K0_inexact:
for i, (f, k) in enumerate(factors):
max_norm = dmp_max_norm(f, u, K0)
f = dmp_quo_ground(f, max_norm, u, K0)
f = dmp_convert(f, u, K0, K0_inexact)
factors[i] = (f, k)
coeff = K0.mul(coeff, K0.pow(max_norm, k))
coeff = K0_inexact.convert(coeff, K0)
K0 = K0_inexact
for i, j in enumerate(reversed(J)):
if not j:
continue
term = {(0,)*(u - i) + (1,) + (0,)*i: K0.one}
factors.insert(0, (dmp_from_dict(term, u, K0), j))
return coeff*cont, _sort_factors(factors)
def dmp_factor_list_include(f, u, K):
"""Factor multivariate polynomials into irreducibles in `K[X]`. """
if not u:
return dup_factor_list_include(f, K)
coeff, factors = dmp_factor_list(f, u, K)
if not factors:
return [(dmp_ground(coeff, u), 1)]
else:
g = dmp_mul_ground(factors[0][0], coeff, u, K)
return [(g, factors[0][1])] + factors[1:]
def dup_irreducible_p(f, K):
"""
Returns ``True`` if a univariate polynomial ``f`` has no factors
over its domain.
"""
return dmp_irreducible_p(f, 0, K)
def dmp_irreducible_p(f, u, K):
"""
Returns ``True`` if a multivariate polynomial ``f`` has no factors
over its domain.
"""
_, factors = dmp_factor_list(f, u, K)
if not factors:
return True
elif len(factors) > 1:
return False
else:
_, k = factors[0]
return k == 1
PK ]ZZZ!� �� � sympy/polys/fglmtools.py"""Implementation of matrix FGLM Groebner basis conversion algorithm. """
from sympy.polys.monomials import monomial_mul, monomial_div
def matrix_fglm(F, ring, O_to):
"""
Converts the reduced Groebner basis ``F`` of a zero-dimensional
ideal w.r.t. ``O_from`` to a reduced Groebner basis
w.r.t. ``O_to``.
References
==========
.. [1] J.C. Faugere, P. Gianni, D. Lazard, T. Mora (1994). Efficient
Computation of Zero-dimensional Groebner Bases by Change of
Ordering
"""
domain = ring.domain
ngens = ring.ngens
ring_to = ring.clone(order=O_to)
old_basis = _basis(F, ring)
M = _representing_matrices(old_basis, F, ring)
# V contains the normalforms (wrt O_from) of S
S = [ring.zero_monom]
V = [[domain.one] + [domain.zero] * (len(old_basis) - 1)]
G = []
L = [(i, 0) for i in range(ngens)] # (i, j) corresponds to x_i * S[j]
L.sort(key=lambda k_l: O_to(_incr_k(S[k_l[1]], k_l[0])), reverse=True)
t = L.pop()
P = _identity_matrix(len(old_basis), domain)
while True:
s = len(S)
v = _matrix_mul(M[t[0]], V[t[1]])
_lambda = _matrix_mul(P, v)
if all(_lambda[i] == domain.zero for i in range(s, len(old_basis))):
# there is a linear combination of v by V
lt = ring.term_new(_incr_k(S[t[1]], t[0]), domain.one)
rest = ring.from_dict({S[i]: _lambda[i] for i in range(s)})
g = (lt - rest).set_ring(ring_to)
if g:
G.append(g)
else:
# v is linearly independent from V
P = _update(s, _lambda, P)
S.append(_incr_k(S[t[1]], t[0]))
V.append(v)
L.extend([(i, s) for i in range(ngens)])
L = list(set(L))
L.sort(key=lambda k_l: O_to(_incr_k(S[k_l[1]], k_l[0])), reverse=True)
L = [(k, l) for (k, l) in L if all(monomial_div(_incr_k(S[l], k), g.LM) is None for g in G)]
if not L:
G = [ g.monic() for g in G ]
return sorted(G, key=lambda g: O_to(g.LM), reverse=True)
t = L.pop()
def _incr_k(m, k):
return tuple(list(m[:k]) + [m[k] + 1] + list(m[k + 1:]))
def _identity_matrix(n, domain):
M = [[domain.zero]*n for _ in range(n)]
for i in range(n):
M[i][i] = domain.one
return M
def _matrix_mul(M, v):
return [sum(row[i] * v[i] for i in range(len(v))) for row in M]
def _update(s, _lambda, P):
"""
Update ``P`` such that for the updated `P'` `P' v = e_{s}`.
"""
k = min(j for j in range(s, len(_lambda)) if _lambda[j] != 0)
for r in range(len(_lambda)):
if r != k:
P[r] = [P[r][j] - (P[k][j] * _lambda[r]) / _lambda[k] for j in range(len(P[r]))]
P[k] = [P[k][j] / _lambda[k] for j in range(len(P[k]))]
P[k], P[s] = P[s], P[k]
return P
def _representing_matrices(basis, G, ring):
r"""
Compute the matrices corresponding to the linear maps `m \mapsto
x_i m` for all variables `x_i`.
"""
domain = ring.domain
u = ring.ngens-1
def var(i):
return tuple([0] * i + [1] + [0] * (u - i))
def representing_matrix(m):
M = [[domain.zero] * len(basis) for _ in range(len(basis))]
for i, v in enumerate(basis):
r = ring.term_new(monomial_mul(m, v), domain.one).rem(G)
for monom, coeff in r.terms():
j = basis.index(monom)
M[j][i] = coeff
return M
return [representing_matrix(var(i)) for i in range(u + 1)]
def _basis(G, ring):
r"""
Computes a list of monomials which are not divisible by the leading
monomials wrt to ``O`` of ``G``. These monomials are a basis of
`K[X_1, \ldots, X_n]/(G)`.
"""
order = ring.order
leading_monomials = [g.LM for g in G]
candidates = [ring.zero_monom]
basis = []
while candidates:
t = candidates.pop()
basis.append(t)
new_candidates = [_incr_k(t, k) for k in range(ring.ngens)
if all(monomial_div(_incr_k(t, k), lmg) is None
for lmg in leading_monomials)]
candidates.extend(new_candidates)
candidates.sort(key=order, reverse=True)
basis = list(set(basis))
return sorted(basis, key=order)
PK ]ZZZ�ڙ�R �R sympy/polys/fields.py"""Sparse rational function fields. """
from __future__ import annotations
from typing import Any
from functools import reduce
from operator import add, mul, lt, le, gt, ge
from sympy.core.expr import Expr
from sympy.core.mod import Mod
from sympy.core.numbers import Exp1
from sympy.core.singleton import S
from sympy.core.symbol import Symbol
from sympy.core.sympify import CantSympify, sympify
from sympy.functions.elementary.exponential import ExpBase
from sympy.polys.domains.domainelement import DomainElement
from sympy.polys.domains.fractionfield import FractionField
from sympy.polys.domains.polynomialring import PolynomialRing
from sympy.polys.constructor import construct_domain
from sympy.polys.orderings import lex
from sympy.polys.polyerrors import CoercionFailed
from sympy.polys.polyoptions import build_options
from sympy.polys.polyutils import _parallel_dict_from_expr
from sympy.polys.rings import PolyElement
from sympy.printing.defaults import DefaultPrinting
from sympy.utilities import public
from sympy.utilities.iterables import is_sequence
from sympy.utilities.magic import pollute
@public
def field(symbols, domain, order=lex):
"""Construct new rational function field returning (field, x1, ..., xn). """
_field = FracField(symbols, domain, order)
return (_field,) + _field.gens
@public
def xfield(symbols, domain, order=lex):
"""Construct new rational function field returning (field, (x1, ..., xn)). """
_field = FracField(symbols, domain, order)
return (_field, _field.gens)
@public
def vfield(symbols, domain, order=lex):
"""Construct new rational function field and inject generators into global namespace. """
_field = FracField(symbols, domain, order)
pollute([ sym.name for sym in _field.symbols ], _field.gens)
return _field
@public
def sfield(exprs, *symbols, **options):
"""Construct a field deriving generators and domain
from options and input expressions.
Parameters
==========
exprs : py:class:`~.Expr` or sequence of :py:class:`~.Expr` (sympifiable)
symbols : sequence of :py:class:`~.Symbol`/:py:class:`~.Expr`
options : keyword arguments understood by :py:class:`~.Options`
Examples
========
>>> from sympy import exp, log, symbols, sfield
>>> x = symbols("x")
>>> K, f = sfield((x*log(x) + 4*x**2)*exp(1/x + log(x)/3)/x**2)
>>> K
Rational function field in x, exp(1/x), log(x), x**(1/3) over ZZ with lex order
>>> f
(4*x**2*(exp(1/x)) + x*(exp(1/x))*(log(x)))/((x**(1/3))**5)
"""
single = False
if not is_sequence(exprs):
exprs, single = [exprs], True
exprs = list(map(sympify, exprs))
opt = build_options(symbols, options)
numdens = []
for expr in exprs:
numdens.extend(expr.as_numer_denom())
reps, opt = _parallel_dict_from_expr(numdens, opt)
if opt.domain is None:
# NOTE: this is inefficient because construct_domain() automatically
# performs conversion to the target domain. It shouldn't do this.
coeffs = sum([list(rep.values()) for rep in reps], [])
opt.domain, _ = construct_domain(coeffs, opt=opt)
_field = FracField(opt.gens, opt.domain, opt.order)
fracs = []
for i in range(0, len(reps), 2):
fracs.append(_field(tuple(reps[i:i+2])))
if single:
return (_field, fracs[0])
else:
return (_field, fracs)
_field_cache: dict[Any, Any] = {}
class FracField(DefaultPrinting):
"""Multivariate distributed rational function field. """
def __new__(cls, symbols, domain, order=lex):
from sympy.polys.rings import PolyRing
ring = PolyRing(symbols, domain, order)
symbols = ring.symbols
ngens = ring.ngens
domain = ring.domain
order = ring.order
_hash_tuple = (cls.__name__, symbols, ngens, domain, order)
obj = _field_cache.get(_hash_tuple)
if obj is None:
obj = object.__new__(cls)
obj._hash_tuple = _hash_tuple
obj._hash = hash(_hash_tuple)
obj.ring = ring
obj.dtype = type("FracElement", (FracElement,), {"field": obj})
obj.symbols = symbols
obj.ngens = ngens
obj.domain = domain
obj.order = order
obj.zero = obj.dtype(ring.zero)
obj.one = obj.dtype(ring.one)
obj.gens = obj._gens()
for symbol, generator in zip(obj.symbols, obj.gens):
if isinstance(symbol, Symbol):
name = symbol.name
if not hasattr(obj, name):
setattr(obj, name, generator)
_field_cache[_hash_tuple] = obj
return obj
def _gens(self):
"""Return a list of polynomial generators. """
return tuple([ self.dtype(gen) for gen in self.ring.gens ])
def __getnewargs__(self):
return (self.symbols, self.domain, self.order)
def __hash__(self):
return self._hash
def index(self, gen):
if isinstance(gen, self.dtype):
return self.ring.index(gen.to_poly())
else:
raise ValueError("expected a %s, got %s instead" % (self.dtype,gen))
def __eq__(self, other):
return isinstance(other, FracField) and \
(self.symbols, self.ngens, self.domain, self.order) == \
(other.symbols, other.ngens, other.domain, other.order)
def __ne__(self, other):
return not self == other
def raw_new(self, numer, denom=None):
return self.dtype(numer, denom)
def new(self, numer, denom=None):
if denom is None: denom = self.ring.one
numer, denom = numer.cancel(denom)
return self.raw_new(numer, denom)
def domain_new(self, element):
return self.domain.convert(element)
def ground_new(self, element):
try:
return self.new(self.ring.ground_new(element))
except CoercionFailed:
domain = self.domain
if not domain.is_Field and domain.has_assoc_Field:
ring = self.ring
ground_field = domain.get_field()
element = ground_field.convert(element)
numer = ring.ground_new(ground_field.numer(element))
denom = ring.ground_new(ground_field.denom(element))
return self.raw_new(numer, denom)
else:
raise
def field_new(self, element):
if isinstance(element, FracElement):
if self == element.field:
return element
if isinstance(self.domain, FractionField) and \
self.domain.field == element.field:
return self.ground_new(element)
elif isinstance(self.domain, PolynomialRing) and \
self.domain.ring.to_field() == element.field:
return self.ground_new(element)
else:
raise NotImplementedError("conversion")
elif isinstance(element, PolyElement):
denom, numer = element.clear_denoms()
if isinstance(self.domain, PolynomialRing) and \
numer.ring == self.domain.ring:
numer = self.ring.ground_new(numer)
elif isinstance(self.domain, FractionField) and \
numer.ring == self.domain.field.to_ring():
numer = self.ring.ground_new(numer)
else:
numer = numer.set_ring(self.ring)
denom = self.ring.ground_new(denom)
return self.raw_new(numer, denom)
elif isinstance(element, tuple) and len(element) == 2:
numer, denom = list(map(self.ring.ring_new, element))
return self.new(numer, denom)
elif isinstance(element, str):
raise NotImplementedError("parsing")
elif isinstance(element, Expr):
return self.from_expr(element)
else:
return self.ground_new(element)
__call__ = field_new
def _rebuild_expr(self, expr, mapping):
domain = self.domain
powers = tuple((gen, gen.as_base_exp()) for gen in mapping.keys()
if gen.is_Pow or isinstance(gen, ExpBase))
def _rebuild(expr):
generator = mapping.get(expr)
if generator is not None:
return generator
elif expr.is_Add:
return reduce(add, list(map(_rebuild, expr.args)))
elif expr.is_Mul:
return reduce(mul, list(map(_rebuild, expr.args)))
elif expr.is_Pow or isinstance(expr, (ExpBase, Exp1)):
b, e = expr.as_base_exp()
# look for bg**eg whose integer power may be b**e
for gen, (bg, eg) in powers:
if bg == b and Mod(e, eg) == 0:
return mapping.get(gen)**int(e/eg)
if e.is_Integer and e is not S.One:
return _rebuild(b)**int(e)
elif mapping.get(1/expr) is not None:
return 1/mapping.get(1/expr)
try:
return domain.convert(expr)
except CoercionFailed:
if not domain.is_Field and domain.has_assoc_Field:
return domain.get_field().convert(expr)
else:
raise
return _rebuild(expr)
def from_expr(self, expr):
mapping = dict(list(zip(self.symbols, self.gens)))
try:
frac = self._rebuild_expr(sympify(expr), mapping)
except CoercionFailed:
raise ValueError("expected an expression convertible to a rational function in %s, got %s" % (self, expr))
else:
return self.field_new(frac)
def to_domain(self):
return FractionField(self)
def to_ring(self):
from sympy.polys.rings import PolyRing
return PolyRing(self.symbols, self.domain, self.order)
class FracElement(DomainElement, DefaultPrinting, CantSympify):
"""Element of multivariate distributed rational function field. """
def __init__(self, numer, denom=None):
if denom is None:
denom = self.field.ring.one
elif not denom:
raise ZeroDivisionError("zero denominator")
self.numer = numer
self.denom = denom
def raw_new(f, numer, denom):
return f.__class__(numer, denom)
def new(f, numer, denom):
return f.raw_new(*numer.cancel(denom))
def to_poly(f):
if f.denom != 1:
raise ValueError("f.denom should be 1")
return f.numer
def parent(self):
return self.field.to_domain()
def __getnewargs__(self):
return (self.field, self.numer, self.denom)
_hash = None
def __hash__(self):
_hash = self._hash
if _hash is None:
self._hash = _hash = hash((self.field, self.numer, self.denom))
return _hash
def copy(self):
return self.raw_new(self.numer.copy(), self.denom.copy())
def set_field(self, new_field):
if self.field == new_field:
return self
else:
new_ring = new_field.ring
numer = self.numer.set_ring(new_ring)
denom = self.denom.set_ring(new_ring)
return new_field.new(numer, denom)
def as_expr(self, *symbols):
return self.numer.as_expr(*symbols)/self.denom.as_expr(*symbols)
def __eq__(f, g):
if isinstance(g, FracElement) and f.field == g.field:
return f.numer == g.numer and f.denom == g.denom
else:
return f.numer == g and f.denom == f.field.ring.one
def __ne__(f, g):
return not f == g
def __bool__(f):
return bool(f.numer)
def sort_key(self):
return (self.denom.sort_key(), self.numer.sort_key())
def _cmp(f1, f2, op):
if isinstance(f2, f1.field.dtype):
return op(f1.sort_key(), f2.sort_key())
else:
return NotImplemented
def __lt__(f1, f2):
return f1._cmp(f2, lt)
def __le__(f1, f2):
return f1._cmp(f2, le)
def __gt__(f1, f2):
return f1._cmp(f2, gt)
def __ge__(f1, f2):
return f1._cmp(f2, ge)
def __pos__(f):
"""Negate all coefficients in ``f``. """
return f.raw_new(f.numer, f.denom)
def __neg__(f):
"""Negate all coefficients in ``f``. """
return f.raw_new(-f.numer, f.denom)
def _extract_ground(self, element):
domain = self.field.domain
try:
element = domain.convert(element)
except CoercionFailed:
if not domain.is_Field and domain.has_assoc_Field:
ground_field = domain.get_field()
try:
element = ground_field.convert(element)
except CoercionFailed:
pass
else:
return -1, ground_field.numer(element), ground_field.denom(element)
return 0, None, None
else:
return 1, element, None
def __add__(f, g):
"""Add rational functions ``f`` and ``g``. """
field = f.field
if not g:
return f
elif not f:
return g
elif isinstance(g, field.dtype):
if f.denom == g.denom:
return f.new(f.numer + g.numer, f.denom)
else:
return f.new(f.numer*g.denom + f.denom*g.numer, f.denom*g.denom)
elif isinstance(g, field.ring.dtype):
return f.new(f.numer + f.denom*g, f.denom)
else:
if isinstance(g, FracElement):
if isinstance(field.domain, FractionField) and field.domain.field == g.field:
pass
elif isinstance(g.field.domain, FractionField) and g.field.domain.field == field:
return g.__radd__(f)
else:
return NotImplemented
elif isinstance(g, PolyElement):
if isinstance(field.domain, PolynomialRing) and field.domain.ring == g.ring:
pass
else:
return g.__radd__(f)
return f.__radd__(g)
def __radd__(f, c):
if isinstance(c, f.field.ring.dtype):
return f.new(f.numer + f.denom*c, f.denom)
op, g_numer, g_denom = f._extract_ground(c)
if op == 1:
return f.new(f.numer + f.denom*g_numer, f.denom)
elif not op:
return NotImplemented
else:
return f.new(f.numer*g_denom + f.denom*g_numer, f.denom*g_denom)
def __sub__(f, g):
"""Subtract rational functions ``f`` and ``g``. """
field = f.field
if not g:
return f
elif not f:
return -g
elif isinstance(g, field.dtype):
if f.denom == g.denom:
return f.new(f.numer - g.numer, f.denom)
else:
return f.new(f.numer*g.denom - f.denom*g.numer, f.denom*g.denom)
elif isinstance(g, field.ring.dtype):
return f.new(f.numer - f.denom*g, f.denom)
else:
if isinstance(g, FracElement):
if isinstance(field.domain, FractionField) and field.domain.field == g.field:
pass
elif isinstance(g.field.domain, FractionField) and g.field.domain.field == field:
return g.__rsub__(f)
else:
return NotImplemented
elif isinstance(g, PolyElement):
if isinstance(field.domain, PolynomialRing) and field.domain.ring == g.ring:
pass
else:
return g.__rsub__(f)
op, g_numer, g_denom = f._extract_ground(g)
if op == 1:
return f.new(f.numer - f.denom*g_numer, f.denom)
elif not op:
return NotImplemented
else:
return f.new(f.numer*g_denom - f.denom*g_numer, f.denom*g_denom)
def __rsub__(f, c):
if isinstance(c, f.field.ring.dtype):
return f.new(-f.numer + f.denom*c, f.denom)
op, g_numer, g_denom = f._extract_ground(c)
if op == 1:
return f.new(-f.numer + f.denom*g_numer, f.denom)
elif not op:
return NotImplemented
else:
return f.new(-f.numer*g_denom + f.denom*g_numer, f.denom*g_denom)
def __mul__(f, g):
"""Multiply rational functions ``f`` and ``g``. """
field = f.field
if not f or not g:
return field.zero
elif isinstance(g, field.dtype):
return f.new(f.numer*g.numer, f.denom*g.denom)
elif isinstance(g, field.ring.dtype):
return f.new(f.numer*g, f.denom)
else:
if isinstance(g, FracElement):
if isinstance(field.domain, FractionField) and field.domain.field == g.field:
pass
elif isinstance(g.field.domain, FractionField) and g.field.domain.field == field:
return g.__rmul__(f)
else:
return NotImplemented
elif isinstance(g, PolyElement):
if isinstance(field.domain, PolynomialRing) and field.domain.ring == g.ring:
pass
else:
return g.__rmul__(f)
return f.__rmul__(g)
def __rmul__(f, c):
if isinstance(c, f.field.ring.dtype):
return f.new(f.numer*c, f.denom)
op, g_numer, g_denom = f._extract_ground(c)
if op == 1:
return f.new(f.numer*g_numer, f.denom)
elif not op:
return NotImplemented
else:
return f.new(f.numer*g_numer, f.denom*g_denom)
def __truediv__(f, g):
"""Computes quotient of fractions ``f`` and ``g``. """
field = f.field
if not g:
raise ZeroDivisionError
elif isinstance(g, field.dtype):
return f.new(f.numer*g.denom, f.denom*g.numer)
elif isinstance(g, field.ring.dtype):
return f.new(f.numer, f.denom*g)
else:
if isinstance(g, FracElement):
if isinstance(field.domain, FractionField) and field.domain.field == g.field:
pass
elif isinstance(g.field.domain, FractionField) and g.field.domain.field == field:
return g.__rtruediv__(f)
else:
return NotImplemented
elif isinstance(g, PolyElement):
if isinstance(field.domain, PolynomialRing) and field.domain.ring == g.ring:
pass
else:
return g.__rtruediv__(f)
op, g_numer, g_denom = f._extract_ground(g)
if op == 1:
return f.new(f.numer, f.denom*g_numer)
elif not op:
return NotImplemented
else:
return f.new(f.numer*g_denom, f.denom*g_numer)
def __rtruediv__(f, c):
if not f:
raise ZeroDivisionError
elif isinstance(c, f.field.ring.dtype):
return f.new(f.denom*c, f.numer)
op, g_numer, g_denom = f._extract_ground(c)
if op == 1:
return f.new(f.denom*g_numer, f.numer)
elif not op:
return NotImplemented
else:
return f.new(f.denom*g_numer, f.numer*g_denom)
def __pow__(f, n):
"""Raise ``f`` to a non-negative power ``n``. """
if n >= 0:
return f.raw_new(f.numer**n, f.denom**n)
elif not f:
raise ZeroDivisionError
else:
return f.raw_new(f.denom**-n, f.numer**-n)
def diff(f, x):
"""Computes partial derivative in ``x``.
Examples
========
>>> from sympy.polys.fields import field
>>> from sympy.polys.domains import ZZ
>>> _, x, y, z = field("x,y,z", ZZ)
>>> ((x**2 + y)/(z + 1)).diff(x)
2*x/(z + 1)
"""
x = x.to_poly()
return f.new(f.numer.diff(x)*f.denom - f.numer*f.denom.diff(x), f.denom**2)
def __call__(f, *values):
if 0 < len(values) <= f.field.ngens:
return f.evaluate(list(zip(f.field.gens, values)))
else:
raise ValueError("expected at least 1 and at most %s values, got %s" % (f.field.ngens, len(values)))
def evaluate(f, x, a=None):
if isinstance(x, list) and a is None:
x = [ (X.to_poly(), a) for X, a in x ]
numer, denom = f.numer.evaluate(x), f.denom.evaluate(x)
else:
x = x.to_poly()
numer, denom = f.numer.evaluate(x, a), f.denom.evaluate(x, a)
field = numer.ring.to_field()
return field.new(numer, denom)
def subs(f, x, a=None):
if isinstance(x, list) and a is None:
x = [ (X.to_poly(), a) for X, a in x ]
numer, denom = f.numer.subs(x), f.denom.subs(x)
else:
x = x.to_poly()
numer, denom = f.numer.subs(x, a), f.denom.subs(x, a)
return f.new(numer, denom)
def compose(f, x, a=None):
raise NotImplementedError
PK ]ZZZWr�8�� �� sympy/polys/galoistools.py"""Dense univariate polynomials with coefficients in Galois fields. """
from math import ceil as _ceil, sqrt as _sqrt, prod
from sympy.core.random import uniform, _randint
from sympy.external.gmpy import SYMPY_INTS, MPZ, invert
from sympy.polys.polyconfig import query
from sympy.polys.polyerrors import ExactQuotientFailed
from sympy.polys.polyutils import _sort_factors
def gf_crt(U, M, K=None):
"""
Chinese Remainder Theorem.
Given a set of integer residues ``u_0,...,u_n`` and a set of
co-prime integer moduli ``m_0,...,m_n``, returns an integer
``u``, such that ``u = u_i mod m_i`` for ``i = ``0,...,n``.
Examples
========
Consider a set of residues ``U = [49, 76, 65]``
and a set of moduli ``M = [99, 97, 95]``. Then we have::
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_crt
>>> gf_crt([49, 76, 65], [99, 97, 95], ZZ)
639985
This is the correct result because::
>>> [639985 % m for m in [99, 97, 95]]
[49, 76, 65]
Note: this is a low-level routine with no error checking.
See Also
========
sympy.ntheory.modular.crt : a higher level crt routine
sympy.ntheory.modular.solve_congruence
"""
p = prod(M, start=K.one)
v = K.zero
for u, m in zip(U, M):
e = p // m
s, _, _ = K.gcdex(e, m)
v += e*(u*s % m)
return v % p
def gf_crt1(M, K):
"""
First part of the Chinese Remainder Theorem.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_crt, gf_crt1, gf_crt2
>>> U = [49, 76, 65]
>>> M = [99, 97, 95]
The following two codes have the same result.
>>> gf_crt(U, M, ZZ)
639985
>>> p, E, S = gf_crt1(M, ZZ)
>>> gf_crt2(U, M, p, E, S, ZZ)
639985
However, it is faster when we want to fix ``M`` and
compute for multiple U, i.e. the following cases:
>>> p, E, S = gf_crt1(M, ZZ)
>>> Us = [[49, 76, 65], [23, 42, 67]]
>>> for U in Us:
... print(gf_crt2(U, M, p, E, S, ZZ))
639985
236237
See Also
========
sympy.ntheory.modular.crt1 : a higher level crt routine
sympy.polys.galoistools.gf_crt
sympy.polys.galoistools.gf_crt2
"""
E, S = [], []
p = prod(M, start=K.one)
for m in M:
E.append(p // m)
S.append(K.gcdex(E[-1], m)[0] % m)
return p, E, S
def gf_crt2(U, M, p, E, S, K):
"""
Second part of the Chinese Remainder Theorem.
See ``gf_crt1`` for usage.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_crt2
>>> U = [49, 76, 65]
>>> M = [99, 97, 95]
>>> p = 912285
>>> E = [9215, 9405, 9603]
>>> S = [62, 24, 12]
>>> gf_crt2(U, M, p, E, S, ZZ)
639985
See Also
========
sympy.ntheory.modular.crt2 : a higher level crt routine
sympy.polys.galoistools.gf_crt
sympy.polys.galoistools.gf_crt1
"""
v = K.zero
for u, m, e, s in zip(U, M, E, S):
v += e*(u*s % m)
return v % p
def gf_int(a, p):
"""
Coerce ``a mod p`` to an integer in the range ``[-p/2, p/2]``.
Examples
========
>>> from sympy.polys.galoistools import gf_int
>>> gf_int(2, 7)
2
>>> gf_int(5, 7)
-2
"""
if a <= p // 2:
return a
else:
return a - p
def gf_degree(f):
"""
Return the leading degree of ``f``.
Examples
========
>>> from sympy.polys.galoistools import gf_degree
>>> gf_degree([1, 1, 2, 0])
3
>>> gf_degree([])
-1
"""
return len(f) - 1
def gf_LC(f, K):
"""
Return the leading coefficient of ``f``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_LC
>>> gf_LC([3, 0, 1], ZZ)
3
"""
if not f:
return K.zero
else:
return f[0]
def gf_TC(f, K):
"""
Return the trailing coefficient of ``f``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_TC
>>> gf_TC([3, 0, 1], ZZ)
1
"""
if not f:
return K.zero
else:
return f[-1]
def gf_strip(f):
"""
Remove leading zeros from ``f``.
Examples
========
>>> from sympy.polys.galoistools import gf_strip
>>> gf_strip([0, 0, 0, 3, 0, 1])
[3, 0, 1]
"""
if not f or f[0]:
return f
k = 0
for coeff in f:
if coeff:
break
else:
k += 1
return f[k:]
def gf_trunc(f, p):
"""
Reduce all coefficients modulo ``p``.
Examples
========
>>> from sympy.polys.galoistools import gf_trunc
>>> gf_trunc([7, -2, 3], 5)
[2, 3, 3]
"""
return gf_strip([ a % p for a in f ])
def gf_normal(f, p, K):
"""
Normalize all coefficients in ``K``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_normal
>>> gf_normal([5, 10, 21, -3], 5, ZZ)
[1, 2]
"""
return gf_trunc(list(map(K, f)), p)
def gf_from_dict(f, p, K):
"""
Create a ``GF(p)[x]`` polynomial from a dict.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_from_dict
>>> gf_from_dict({10: ZZ(4), 4: ZZ(33), 0: ZZ(-1)}, 5, ZZ)
[4, 0, 0, 0, 0, 0, 3, 0, 0, 0, 4]
"""
n, h = max(f.keys()), []
if isinstance(n, SYMPY_INTS):
for k in range(n, -1, -1):
h.append(f.get(k, K.zero) % p)
else:
(n,) = n
for k in range(n, -1, -1):
h.append(f.get((k,), K.zero) % p)
return gf_trunc(h, p)
def gf_to_dict(f, p, symmetric=True):
"""
Convert a ``GF(p)[x]`` polynomial to a dict.
Examples
========
>>> from sympy.polys.galoistools import gf_to_dict
>>> gf_to_dict([4, 0, 0, 0, 0, 0, 3, 0, 0, 0, 4], 5)
{0: -1, 4: -2, 10: -1}
>>> gf_to_dict([4, 0, 0, 0, 0, 0, 3, 0, 0, 0, 4], 5, symmetric=False)
{0: 4, 4: 3, 10: 4}
"""
n, result = gf_degree(f), {}
for k in range(0, n + 1):
if symmetric:
a = gf_int(f[n - k], p)
else:
a = f[n - k]
if a:
result[k] = a
return result
def gf_from_int_poly(f, p):
"""
Create a ``GF(p)[x]`` polynomial from ``Z[x]``.
Examples
========
>>> from sympy.polys.galoistools import gf_from_int_poly
>>> gf_from_int_poly([7, -2, 3], 5)
[2, 3, 3]
"""
return gf_trunc(f, p)
def gf_to_int_poly(f, p, symmetric=True):
"""
Convert a ``GF(p)[x]`` polynomial to ``Z[x]``.
Examples
========
>>> from sympy.polys.galoistools import gf_to_int_poly
>>> gf_to_int_poly([2, 3, 3], 5)
[2, -2, -2]
>>> gf_to_int_poly([2, 3, 3], 5, symmetric=False)
[2, 3, 3]
"""
if symmetric:
return [ gf_int(c, p) for c in f ]
else:
return f
def gf_neg(f, p, K):
"""
Negate a polynomial in ``GF(p)[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_neg
>>> gf_neg([3, 2, 1, 0], 5, ZZ)
[2, 3, 4, 0]
"""
return [ -coeff % p for coeff in f ]
def gf_add_ground(f, a, p, K):
"""
Compute ``f + a`` where ``f`` in ``GF(p)[x]`` and ``a`` in ``GF(p)``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_add_ground
>>> gf_add_ground([3, 2, 4], 2, 5, ZZ)
[3, 2, 1]
"""
if not f:
a = a % p
else:
a = (f[-1] + a) % p
if len(f) > 1:
return f[:-1] + [a]
if not a:
return []
else:
return [a]
def gf_sub_ground(f, a, p, K):
"""
Compute ``f - a`` where ``f`` in ``GF(p)[x]`` and ``a`` in ``GF(p)``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_sub_ground
>>> gf_sub_ground([3, 2, 4], 2, 5, ZZ)
[3, 2, 2]
"""
if not f:
a = -a % p
else:
a = (f[-1] - a) % p
if len(f) > 1:
return f[:-1] + [a]
if not a:
return []
else:
return [a]
def gf_mul_ground(f, a, p, K):
"""
Compute ``f * a`` where ``f`` in ``GF(p)[x]`` and ``a`` in ``GF(p)``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_mul_ground
>>> gf_mul_ground([3, 2, 4], 2, 5, ZZ)
[1, 4, 3]
"""
if not a:
return []
else:
return [ (a*b) % p for b in f ]
def gf_quo_ground(f, a, p, K):
"""
Compute ``f/a`` where ``f`` in ``GF(p)[x]`` and ``a`` in ``GF(p)``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_quo_ground
>>> gf_quo_ground(ZZ.map([3, 2, 4]), ZZ(2), 5, ZZ)
[4, 1, 2]
"""
return gf_mul_ground(f, K.invert(a, p), p, K)
def gf_add(f, g, p, K):
"""
Add polynomials in ``GF(p)[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_add
>>> gf_add([3, 2, 4], [2, 2, 2], 5, ZZ)
[4, 1]
"""
if not f:
return g
if not g:
return f
df = gf_degree(f)
dg = gf_degree(g)
if df == dg:
return gf_strip([ (a + b) % p for a, b in zip(f, g) ])
else:
k = abs(df - dg)
if df > dg:
h, f = f[:k], f[k:]
else:
h, g = g[:k], g[k:]
return h + [ (a + b) % p for a, b in zip(f, g) ]
def gf_sub(f, g, p, K):
"""
Subtract polynomials in ``GF(p)[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_sub
>>> gf_sub([3, 2, 4], [2, 2, 2], 5, ZZ)
[1, 0, 2]
"""
if not g:
return f
if not f:
return gf_neg(g, p, K)
df = gf_degree(f)
dg = gf_degree(g)
if df == dg:
return gf_strip([ (a - b) % p for a, b in zip(f, g) ])
else:
k = abs(df - dg)
if df > dg:
h, f = f[:k], f[k:]
else:
h, g = gf_neg(g[:k], p, K), g[k:]
return h + [ (a - b) % p for a, b in zip(f, g) ]
def gf_mul(f, g, p, K):
"""
Multiply polynomials in ``GF(p)[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_mul
>>> gf_mul([3, 2, 4], [2, 2, 2], 5, ZZ)
[1, 0, 3, 2, 3]
"""
df = gf_degree(f)
dg = gf_degree(g)
dh = df + dg
h = [0]*(dh + 1)
for i in range(0, dh + 1):
coeff = K.zero
for j in range(max(0, i - dg), min(i, df) + 1):
coeff += f[j]*g[i - j]
h[i] = coeff % p
return gf_strip(h)
def gf_sqr(f, p, K):
"""
Square polynomials in ``GF(p)[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_sqr
>>> gf_sqr([3, 2, 4], 5, ZZ)
[4, 2, 3, 1, 1]
"""
df = gf_degree(f)
dh = 2*df
h = [0]*(dh + 1)
for i in range(0, dh + 1):
coeff = K.zero
jmin = max(0, i - df)
jmax = min(i, df)
n = jmax - jmin + 1
jmax = jmin + n // 2 - 1
for j in range(jmin, jmax + 1):
coeff += f[j]*f[i - j]
coeff += coeff
if n & 1:
elem = f[jmax + 1]
coeff += elem**2
h[i] = coeff % p
return gf_strip(h)
def gf_add_mul(f, g, h, p, K):
"""
Returns ``f + g*h`` where ``f``, ``g``, ``h`` in ``GF(p)[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_add_mul
>>> gf_add_mul([3, 2, 4], [2, 2, 2], [1, 4], 5, ZZ)
[2, 3, 2, 2]
"""
return gf_add(f, gf_mul(g, h, p, K), p, K)
def gf_sub_mul(f, g, h, p, K):
"""
Compute ``f - g*h`` where ``f``, ``g``, ``h`` in ``GF(p)[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_sub_mul
>>> gf_sub_mul([3, 2, 4], [2, 2, 2], [1, 4], 5, ZZ)
[3, 3, 2, 1]
"""
return gf_sub(f, gf_mul(g, h, p, K), p, K)
def gf_expand(F, p, K):
"""
Expand results of :func:`~.factor` in ``GF(p)[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_expand
>>> gf_expand([([3, 2, 4], 1), ([2, 2], 2), ([3, 1], 3)], 5, ZZ)
[4, 3, 0, 3, 0, 1, 4, 1]
"""
if isinstance(F, tuple):
lc, F = F
else:
lc = K.one
g = [lc]
for f, k in F:
f = gf_pow(f, k, p, K)
g = gf_mul(g, f, p, K)
return g
def gf_div(f, g, p, K):
"""
Division with remainder in ``GF(p)[x]``.
Given univariate polynomials ``f`` and ``g`` with coefficients in a
finite field with ``p`` elements, returns polynomials ``q`` and ``r``
(quotient and remainder) such that ``f = q*g + r``.
Consider polynomials ``x**3 + x + 1`` and ``x**2 + x`` in GF(2)::
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_div, gf_add_mul
>>> gf_div(ZZ.map([1, 0, 1, 1]), ZZ.map([1, 1, 0]), 2, ZZ)
([1, 1], [1])
As result we obtained quotient ``x + 1`` and remainder ``1``, thus::
>>> gf_add_mul(ZZ.map([1]), ZZ.map([1, 1]), ZZ.map([1, 1, 0]), 2, ZZ)
[1, 0, 1, 1]
References
==========
.. [1] [Monagan93]_
.. [2] [Gathen99]_
"""
df = gf_degree(f)
dg = gf_degree(g)
if not g:
raise ZeroDivisionError("polynomial division")
elif df < dg:
return [], f
inv = K.invert(g[0], p)
h, dq, dr = list(f), df - dg, dg - 1
for i in range(0, df + 1):
coeff = h[i]
for j in range(max(0, dg - i), min(df - i, dr) + 1):
coeff -= h[i + j - dg] * g[dg - j]
if i <= dq:
coeff *= inv
h[i] = coeff % p
return h[:dq + 1], gf_strip(h[dq + 1:])
def gf_rem(f, g, p, K):
"""
Compute polynomial remainder in ``GF(p)[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_rem
>>> gf_rem(ZZ.map([1, 0, 1, 1]), ZZ.map([1, 1, 0]), 2, ZZ)
[1]
"""
return gf_div(f, g, p, K)[1]
def gf_quo(f, g, p, K):
"""
Compute exact quotient in ``GF(p)[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_quo
>>> gf_quo(ZZ.map([1, 0, 1, 1]), ZZ.map([1, 1, 0]), 2, ZZ)
[1, 1]
>>> gf_quo(ZZ.map([1, 0, 3, 2, 3]), ZZ.map([2, 2, 2]), 5, ZZ)
[3, 2, 4]
"""
df = gf_degree(f)
dg = gf_degree(g)
if not g:
raise ZeroDivisionError("polynomial division")
elif df < dg:
return []
inv = K.invert(g[0], p)
h, dq, dr = f[:], df - dg, dg - 1
for i in range(0, dq + 1):
coeff = h[i]
for j in range(max(0, dg - i), min(df - i, dr) + 1):
coeff -= h[i + j - dg] * g[dg - j]
h[i] = (coeff * inv) % p
return h[:dq + 1]
def gf_exquo(f, g, p, K):
"""
Compute polynomial quotient in ``GF(p)[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_exquo
>>> gf_exquo(ZZ.map([1, 0, 3, 2, 3]), ZZ.map([2, 2, 2]), 5, ZZ)
[3, 2, 4]
>>> gf_exquo(ZZ.map([1, 0, 1, 1]), ZZ.map([1, 1, 0]), 2, ZZ)
Traceback (most recent call last):
...
ExactQuotientFailed: [1, 1, 0] does not divide [1, 0, 1, 1]
"""
q, r = gf_div(f, g, p, K)
if not r:
return q
else:
raise ExactQuotientFailed(f, g)
def gf_lshift(f, n, K):
"""
Efficiently multiply ``f`` by ``x**n``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_lshift
>>> gf_lshift([3, 2, 4], 4, ZZ)
[3, 2, 4, 0, 0, 0, 0]
"""
if not f:
return f
else:
return f + [K.zero]*n
def gf_rshift(f, n, K):
"""
Efficiently divide ``f`` by ``x**n``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_rshift
>>> gf_rshift([1, 2, 3, 4, 0], 3, ZZ)
([1, 2], [3, 4, 0])
"""
if not n:
return f, []
else:
return f[:-n], f[-n:]
def gf_pow(f, n, p, K):
"""
Compute ``f**n`` in ``GF(p)[x]`` using repeated squaring.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_pow
>>> gf_pow([3, 2, 4], 3, 5, ZZ)
[2, 4, 4, 2, 2, 1, 4]
"""
if not n:
return [K.one]
elif n == 1:
return f
elif n == 2:
return gf_sqr(f, p, K)
h = [K.one]
while True:
if n & 1:
h = gf_mul(h, f, p, K)
n -= 1
n >>= 1
if not n:
break
f = gf_sqr(f, p, K)
return h
def gf_frobenius_monomial_base(g, p, K):
"""
return the list of ``x**(i*p) mod g in Z_p`` for ``i = 0, .., n - 1``
where ``n = gf_degree(g)``
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_frobenius_monomial_base
>>> g = ZZ.map([1, 0, 2, 1])
>>> gf_frobenius_monomial_base(g, 5, ZZ)
[[1], [4, 4, 2], [1, 2]]
"""
n = gf_degree(g)
if n == 0:
return []
b = [0]*n
b[0] = [1]
if p < n:
for i in range(1, n):
mon = gf_lshift(b[i - 1], p, K)
b[i] = gf_rem(mon, g, p, K)
elif n > 1:
b[1] = gf_pow_mod([K.one, K.zero], p, g, p, K)
for i in range(2, n):
b[i] = gf_mul(b[i - 1], b[1], p, K)
b[i] = gf_rem(b[i], g, p, K)
return b
def gf_frobenius_map(f, g, b, p, K):
"""
compute gf_pow_mod(f, p, g, p, K) using the Frobenius map
Parameters
==========
f, g : polynomials in ``GF(p)[x]``
b : frobenius monomial base
p : prime number
K : domain
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_frobenius_monomial_base, gf_frobenius_map
>>> f = ZZ.map([2, 1, 0, 1])
>>> g = ZZ.map([1, 0, 2, 1])
>>> p = 5
>>> b = gf_frobenius_monomial_base(g, p, ZZ)
>>> r = gf_frobenius_map(f, g, b, p, ZZ)
>>> gf_frobenius_map(f, g, b, p, ZZ)
[4, 0, 3]
"""
m = gf_degree(g)
if gf_degree(f) >= m:
f = gf_rem(f, g, p, K)
if not f:
return []
n = gf_degree(f)
sf = [f[-1]]
for i in range(1, n + 1):
v = gf_mul_ground(b[i], f[n - i], p, K)
sf = gf_add(sf, v, p, K)
return sf
def _gf_pow_pnm1d2(f, n, g, b, p, K):
"""
utility function for ``gf_edf_zassenhaus``
Compute ``f**((p**n - 1) // 2)`` in ``GF(p)[x]/(g)``
``f**((p**n - 1) // 2) = (f*f**p*...*f**(p**n - 1))**((p - 1) // 2)``
"""
f = gf_rem(f, g, p, K)
h = f
r = f
for i in range(1, n):
h = gf_frobenius_map(h, g, b, p, K)
r = gf_mul(r, h, p, K)
r = gf_rem(r, g, p, K)
res = gf_pow_mod(r, (p - 1)//2, g, p, K)
return res
def gf_pow_mod(f, n, g, p, K):
"""
Compute ``f**n`` in ``GF(p)[x]/(g)`` using repeated squaring.
Given polynomials ``f`` and ``g`` in ``GF(p)[x]`` and a non-negative
integer ``n``, efficiently computes ``f**n (mod g)`` i.e. the remainder
of ``f**n`` from division by ``g``, using the repeated squaring algorithm.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_pow_mod
>>> gf_pow_mod(ZZ.map([3, 2, 4]), 3, ZZ.map([1, 1]), 5, ZZ)
[]
References
==========
.. [1] [Gathen99]_
"""
if not n:
return [K.one]
elif n == 1:
return gf_rem(f, g, p, K)
elif n == 2:
return gf_rem(gf_sqr(f, p, K), g, p, K)
h = [K.one]
while True:
if n & 1:
h = gf_mul(h, f, p, K)
h = gf_rem(h, g, p, K)
n -= 1
n >>= 1
if not n:
break
f = gf_sqr(f, p, K)
f = gf_rem(f, g, p, K)
return h
def gf_gcd(f, g, p, K):
"""
Euclidean Algorithm in ``GF(p)[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_gcd
>>> gf_gcd(ZZ.map([3, 2, 4]), ZZ.map([2, 2, 3]), 5, ZZ)
[1, 3]
"""
while g:
f, g = g, gf_rem(f, g, p, K)
return gf_monic(f, p, K)[1]
def gf_lcm(f, g, p, K):
"""
Compute polynomial LCM in ``GF(p)[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_lcm
>>> gf_lcm(ZZ.map([3, 2, 4]), ZZ.map([2, 2, 3]), 5, ZZ)
[1, 2, 0, 4]
"""
if not f or not g:
return []
h = gf_quo(gf_mul(f, g, p, K),
gf_gcd(f, g, p, K), p, K)
return gf_monic(h, p, K)[1]
def gf_cofactors(f, g, p, K):
"""
Compute polynomial GCD and cofactors in ``GF(p)[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_cofactors
>>> gf_cofactors(ZZ.map([3, 2, 4]), ZZ.map([2, 2, 3]), 5, ZZ)
([1, 3], [3, 3], [2, 1])
"""
if not f and not g:
return ([], [], [])
h = gf_gcd(f, g, p, K)
return (h, gf_quo(f, h, p, K),
gf_quo(g, h, p, K))
def gf_gcdex(f, g, p, K):
"""
Extended Euclidean Algorithm in ``GF(p)[x]``.
Given polynomials ``f`` and ``g`` in ``GF(p)[x]``, computes polynomials
``s``, ``t`` and ``h``, such that ``h = gcd(f, g)`` and ``s*f + t*g = h``.
The typical application of EEA is solving polynomial diophantine equations.
Consider polynomials ``f = (x + 7) (x + 1)``, ``g = (x + 7) (x**2 + 1)``
in ``GF(11)[x]``. Application of Extended Euclidean Algorithm gives::
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_gcdex, gf_mul, gf_add
>>> s, t, g = gf_gcdex(ZZ.map([1, 8, 7]), ZZ.map([1, 7, 1, 7]), 11, ZZ)
>>> s, t, g
([5, 6], [6], [1, 7])
As result we obtained polynomials ``s = 5*x + 6`` and ``t = 6``, and
additionally ``gcd(f, g) = x + 7``. This is correct because::
>>> S = gf_mul(s, ZZ.map([1, 8, 7]), 11, ZZ)
>>> T = gf_mul(t, ZZ.map([1, 7, 1, 7]), 11, ZZ)
>>> gf_add(S, T, 11, ZZ) == [1, 7]
True
References
==========
.. [1] [Gathen99]_
"""
if not (f or g):
return [K.one], [], []
p0, r0 = gf_monic(f, p, K)
p1, r1 = gf_monic(g, p, K)
if not f:
return [], [K.invert(p1, p)], r1
if not g:
return [K.invert(p0, p)], [], r0
s0, s1 = [K.invert(p0, p)], []
t0, t1 = [], [K.invert(p1, p)]
while True:
Q, R = gf_div(r0, r1, p, K)
if not R:
break
(lc, r1), r0 = gf_monic(R, p, K), r1
inv = K.invert(lc, p)
s = gf_sub_mul(s0, s1, Q, p, K)
t = gf_sub_mul(t0, t1, Q, p, K)
s1, s0 = gf_mul_ground(s, inv, p, K), s1
t1, t0 = gf_mul_ground(t, inv, p, K), t1
return s1, t1, r1
def gf_monic(f, p, K):
"""
Compute LC and a monic polynomial in ``GF(p)[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_monic
>>> gf_monic(ZZ.map([3, 2, 4]), 5, ZZ)
(3, [1, 4, 3])
"""
if not f:
return K.zero, []
else:
lc = f[0]
if K.is_one(lc):
return lc, list(f)
else:
return lc, gf_quo_ground(f, lc, p, K)
def gf_diff(f, p, K):
"""
Differentiate polynomial in ``GF(p)[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_diff
>>> gf_diff([3, 2, 4], 5, ZZ)
[1, 2]
"""
df = gf_degree(f)
h, n = [K.zero]*df, df
for coeff in f[:-1]:
coeff *= K(n)
coeff %= p
if coeff:
h[df - n] = coeff
n -= 1
return gf_strip(h)
def gf_eval(f, a, p, K):
"""
Evaluate ``f(a)`` in ``GF(p)`` using Horner scheme.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_eval
>>> gf_eval([3, 2, 4], 2, 5, ZZ)
0
"""
result = K.zero
for c in f:
result *= a
result += c
result %= p
return result
def gf_multi_eval(f, A, p, K):
"""
Evaluate ``f(a)`` for ``a`` in ``[a_1, ..., a_n]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_multi_eval
>>> gf_multi_eval([3, 2, 4], [0, 1, 2, 3, 4], 5, ZZ)
[4, 4, 0, 2, 0]
"""
return [ gf_eval(f, a, p, K) for a in A ]
def gf_compose(f, g, p, K):
"""
Compute polynomial composition ``f(g)`` in ``GF(p)[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_compose
>>> gf_compose([3, 2, 4], [2, 2, 2], 5, ZZ)
[2, 4, 0, 3, 0]
"""
if len(g) <= 1:
return gf_strip([gf_eval(f, gf_LC(g, K), p, K)])
if not f:
return []
h = [f[0]]
for c in f[1:]:
h = gf_mul(h, g, p, K)
h = gf_add_ground(h, c, p, K)
return h
def gf_compose_mod(g, h, f, p, K):
"""
Compute polynomial composition ``g(h)`` in ``GF(p)[x]/(f)``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_compose_mod
>>> gf_compose_mod(ZZ.map([3, 2, 4]), ZZ.map([2, 2, 2]), ZZ.map([4, 3]), 5, ZZ)
[4]
"""
if not g:
return []
comp = [g[0]]
for a in g[1:]:
comp = gf_mul(comp, h, p, K)
comp = gf_add_ground(comp, a, p, K)
comp = gf_rem(comp, f, p, K)
return comp
def gf_trace_map(a, b, c, n, f, p, K):
"""
Compute polynomial trace map in ``GF(p)[x]/(f)``.
Given a polynomial ``f`` in ``GF(p)[x]``, polynomials ``a``, ``b``,
``c`` in the quotient ring ``GF(p)[x]/(f)`` such that ``b = c**t
(mod f)`` for some positive power ``t`` of ``p``, and a positive
integer ``n``, returns a mapping::
a -> a**t**n, a + a**t + a**t**2 + ... + a**t**n (mod f)
In factorization context, ``b = x**p mod f`` and ``c = x mod f``.
This way we can efficiently compute trace polynomials in equal
degree factorization routine, much faster than with other methods,
like iterated Frobenius algorithm, for large degrees.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_trace_map
>>> gf_trace_map([1, 2], [4, 4], [1, 1], 4, [3, 2, 4], 5, ZZ)
([1, 3], [1, 3])
References
==========
.. [1] [Gathen92]_
"""
u = gf_compose_mod(a, b, f, p, K)
v = b
if n & 1:
U = gf_add(a, u, p, K)
V = b
else:
U = a
V = c
n >>= 1
while n:
u = gf_add(u, gf_compose_mod(u, v, f, p, K), p, K)
v = gf_compose_mod(v, v, f, p, K)
if n & 1:
U = gf_add(U, gf_compose_mod(u, V, f, p, K), p, K)
V = gf_compose_mod(v, V, f, p, K)
n >>= 1
return gf_compose_mod(a, V, f, p, K), U
def _gf_trace_map(f, n, g, b, p, K):
"""
utility for ``gf_edf_shoup``
"""
f = gf_rem(f, g, p, K)
h = f
r = f
for i in range(1, n):
h = gf_frobenius_map(h, g, b, p, K)
r = gf_add(r, h, p, K)
r = gf_rem(r, g, p, K)
return r
def gf_random(n, p, K):
"""
Generate a random polynomial in ``GF(p)[x]`` of degree ``n``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_random
>>> gf_random(10, 5, ZZ) #doctest: +SKIP
[1, 2, 3, 2, 1, 1, 1, 2, 0, 4, 2]
"""
pi = int(p)
return [K.one] + [ K(int(uniform(0, pi))) for i in range(0, n) ]
def gf_irreducible(n, p, K):
"""
Generate random irreducible polynomial of degree ``n`` in ``GF(p)[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_irreducible
>>> gf_irreducible(10, 5, ZZ) #doctest: +SKIP
[1, 4, 2, 2, 3, 2, 4, 1, 4, 0, 4]
"""
while True:
f = gf_random(n, p, K)
if gf_irreducible_p(f, p, K):
return f
def gf_irred_p_ben_or(f, p, K):
"""
Ben-Or's polynomial irreducibility test over finite fields.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_irred_p_ben_or
>>> gf_irred_p_ben_or(ZZ.map([1, 4, 2, 2, 3, 2, 4, 1, 4, 0, 4]), 5, ZZ)
True
>>> gf_irred_p_ben_or(ZZ.map([3, 2, 4]), 5, ZZ)
False
"""
n = gf_degree(f)
if n <= 1:
return True
_, f = gf_monic(f, p, K)
if n < 5:
H = h = gf_pow_mod([K.one, K.zero], p, f, p, K)
for i in range(0, n//2):
g = gf_sub(h, [K.one, K.zero], p, K)
if gf_gcd(f, g, p, K) == [K.one]:
h = gf_compose_mod(h, H, f, p, K)
else:
return False
else:
b = gf_frobenius_monomial_base(f, p, K)
H = h = gf_frobenius_map([K.one, K.zero], f, b, p, K)
for i in range(0, n//2):
g = gf_sub(h, [K.one, K.zero], p, K)
if gf_gcd(f, g, p, K) == [K.one]:
h = gf_frobenius_map(h, f, b, p, K)
else:
return False
return True
def gf_irred_p_rabin(f, p, K):
"""
Rabin's polynomial irreducibility test over finite fields.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_irred_p_rabin
>>> gf_irred_p_rabin(ZZ.map([1, 4, 2, 2, 3, 2, 4, 1, 4, 0, 4]), 5, ZZ)
True
>>> gf_irred_p_rabin(ZZ.map([3, 2, 4]), 5, ZZ)
False
"""
n = gf_degree(f)
if n <= 1:
return True
_, f = gf_monic(f, p, K)
x = [K.one, K.zero]
from sympy.ntheory import factorint
indices = { n//d for d in factorint(n) }
b = gf_frobenius_monomial_base(f, p, K)
h = b[1]
for i in range(1, n):
if i in indices:
g = gf_sub(h, x, p, K)
if gf_gcd(f, g, p, K) != [K.one]:
return False
h = gf_frobenius_map(h, f, b, p, K)
return h == x
_irred_methods = {
'ben-or': gf_irred_p_ben_or,
'rabin': gf_irred_p_rabin,
}
def gf_irreducible_p(f, p, K):
"""
Test irreducibility of a polynomial ``f`` in ``GF(p)[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_irreducible_p
>>> gf_irreducible_p(ZZ.map([1, 4, 2, 2, 3, 2, 4, 1, 4, 0, 4]), 5, ZZ)
True
>>> gf_irreducible_p(ZZ.map([3, 2, 4]), 5, ZZ)
False
"""
method = query('GF_IRRED_METHOD')
if method is not None:
irred = _irred_methods[method](f, p, K)
else:
irred = gf_irred_p_rabin(f, p, K)
return irred
def gf_sqf_p(f, p, K):
"""
Return ``True`` if ``f`` is square-free in ``GF(p)[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_sqf_p
>>> gf_sqf_p(ZZ.map([3, 2, 4]), 5, ZZ)
True
>>> gf_sqf_p(ZZ.map([2, 4, 4, 2, 2, 1, 4]), 5, ZZ)
False
"""
_, f = gf_monic(f, p, K)
if not f:
return True
else:
return gf_gcd(f, gf_diff(f, p, K), p, K) == [K.one]
def gf_sqf_part(f, p, K):
"""
Return square-free part of a ``GF(p)[x]`` polynomial.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_sqf_part
>>> gf_sqf_part(ZZ.map([1, 1, 3, 0, 1, 0, 2, 2, 1]), 5, ZZ)
[1, 4, 3]
"""
_, sqf = gf_sqf_list(f, p, K)
g = [K.one]
for f, _ in sqf:
g = gf_mul(g, f, p, K)
return g
def gf_sqf_list(f, p, K, all=False):
"""
Return the square-free decomposition of a ``GF(p)[x]`` polynomial.
Given a polynomial ``f`` in ``GF(p)[x]``, returns the leading coefficient
of ``f`` and a square-free decomposition ``f_1**e_1 f_2**e_2 ... f_k**e_k``
such that all ``f_i`` are monic polynomials and ``(f_i, f_j)`` for ``i != j``
are co-prime and ``e_1 ... e_k`` are given in increasing order. All trivial
terms (i.e. ``f_i = 1``) are not included in the output.
Consider polynomial ``f = x**11 + 1`` over ``GF(11)[x]``::
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import (
... gf_from_dict, gf_diff, gf_sqf_list, gf_pow,
... )
... # doctest: +NORMALIZE_WHITESPACE
>>> f = gf_from_dict({11: ZZ(1), 0: ZZ(1)}, 11, ZZ)
Note that ``f'(x) = 0``::
>>> gf_diff(f, 11, ZZ)
[]
This phenomenon does not happen in characteristic zero. However we can
still compute square-free decomposition of ``f`` using ``gf_sqf()``::
>>> gf_sqf_list(f, 11, ZZ)
(1, [([1, 1], 11)])
We obtained factorization ``f = (x + 1)**11``. This is correct because::
>>> gf_pow([1, 1], 11, 11, ZZ) == f
True
References
==========
.. [1] [Geddes92]_
"""
n, sqf, factors, r = 1, False, [], int(p)
lc, f = gf_monic(f, p, K)
if gf_degree(f) < 1:
return lc, []
while True:
F = gf_diff(f, p, K)
if F != []:
g = gf_gcd(f, F, p, K)
h = gf_quo(f, g, p, K)
i = 1
while h != [K.one]:
G = gf_gcd(g, h, p, K)
H = gf_quo(h, G, p, K)
if gf_degree(H) > 0:
factors.append((H, i*n))
g, h, i = gf_quo(g, G, p, K), G, i + 1
if g == [K.one]:
sqf = True
else:
f = g
if not sqf:
d = gf_degree(f) // r
for i in range(0, d + 1):
f[i] = f[i*r]
f, n = f[:d + 1], n*r
else:
break
if all:
raise ValueError("'all=True' is not supported yet")
return lc, factors
def gf_Qmatrix(f, p, K):
"""
Calculate Berlekamp's ``Q`` matrix.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_Qmatrix
>>> gf_Qmatrix([3, 2, 4], 5, ZZ)
[[1, 0],
[3, 4]]
>>> gf_Qmatrix([1, 0, 0, 0, 1], 5, ZZ)
[[1, 0, 0, 0],
[0, 4, 0, 0],
[0, 0, 1, 0],
[0, 0, 0, 4]]
"""
n, r = gf_degree(f), int(p)
q = [K.one] + [K.zero]*(n - 1)
Q = [list(q)] + [[]]*(n - 1)
for i in range(1, (n - 1)*r + 1):
qq, c = [(-q[-1]*f[-1]) % p], q[-1]
for j in range(1, n):
qq.append((q[j - 1] - c*f[-j - 1]) % p)
if not (i % r):
Q[i//r] = list(qq)
q = qq
return Q
def gf_Qbasis(Q, p, K):
"""
Compute a basis of the kernel of ``Q``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_Qmatrix, gf_Qbasis
>>> gf_Qbasis(gf_Qmatrix([1, 0, 0, 0, 1], 5, ZZ), 5, ZZ)
[[1, 0, 0, 0], [0, 0, 1, 0]]
>>> gf_Qbasis(gf_Qmatrix([3, 2, 4], 5, ZZ), 5, ZZ)
[[1, 0]]
"""
Q, n = [ list(q) for q in Q ], len(Q)
for k in range(0, n):
Q[k][k] = (Q[k][k] - K.one) % p
for k in range(0, n):
for i in range(k, n):
if Q[k][i]:
break
else:
continue
inv = K.invert(Q[k][i], p)
for j in range(0, n):
Q[j][i] = (Q[j][i]*inv) % p
for j in range(0, n):
t = Q[j][k]
Q[j][k] = Q[j][i]
Q[j][i] = t
for i in range(0, n):
if i != k:
q = Q[k][i]
for j in range(0, n):
Q[j][i] = (Q[j][i] - Q[j][k]*q) % p
for i in range(0, n):
for j in range(0, n):
if i == j:
Q[i][j] = (K.one - Q[i][j]) % p
else:
Q[i][j] = (-Q[i][j]) % p
basis = []
for q in Q:
if any(q):
basis.append(q)
return basis
def gf_berlekamp(f, p, K):
"""
Factor a square-free ``f`` in ``GF(p)[x]`` for small ``p``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_berlekamp
>>> gf_berlekamp([1, 0, 0, 0, 1], 5, ZZ)
[[1, 0, 2], [1, 0, 3]]
"""
Q = gf_Qmatrix(f, p, K)
V = gf_Qbasis(Q, p, K)
for i, v in enumerate(V):
V[i] = gf_strip(list(reversed(v)))
factors = [f]
for k in range(1, len(V)):
for f in list(factors):
s = K.zero
while s < p:
g = gf_sub_ground(V[k], s, p, K)
h = gf_gcd(f, g, p, K)
if h != [K.one] and h != f:
factors.remove(f)
f = gf_quo(f, h, p, K)
factors.extend([f, h])
if len(factors) == len(V):
return _sort_factors(factors, multiple=False)
s += K.one
return _sort_factors(factors, multiple=False)
def gf_ddf_zassenhaus(f, p, K):
"""
Cantor-Zassenhaus: Deterministic Distinct Degree Factorization
Given a monic square-free polynomial ``f`` in ``GF(p)[x]``, computes
partial distinct degree factorization ``f_1 ... f_d`` of ``f`` where
``deg(f_i) != deg(f_j)`` for ``i != j``. The result is returned as a
list of pairs ``(f_i, e_i)`` where ``deg(f_i) > 0`` and ``e_i > 0``
is an argument to the equal degree factorization routine.
Consider the polynomial ``x**15 - 1`` in ``GF(11)[x]``::
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_from_dict
>>> f = gf_from_dict({15: ZZ(1), 0: ZZ(-1)}, 11, ZZ)
Distinct degree factorization gives::
>>> from sympy.polys.galoistools import gf_ddf_zassenhaus
>>> gf_ddf_zassenhaus(f, 11, ZZ)
[([1, 0, 0, 0, 0, 10], 1), ([1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1], 2)]
which means ``x**15 - 1 = (x**5 - 1) (x**10 + x**5 + 1)``. To obtain
factorization into irreducibles, use equal degree factorization
procedure (EDF) with each of the factors.
References
==========
.. [1] [Gathen99]_
.. [2] [Geddes92]_
"""
i, g, factors = 1, [K.one, K.zero], []
b = gf_frobenius_monomial_base(f, p, K)
while 2*i <= gf_degree(f):
g = gf_frobenius_map(g, f, b, p, K)
h = gf_gcd(f, gf_sub(g, [K.one, K.zero], p, K), p, K)
if h != [K.one]:
factors.append((h, i))
f = gf_quo(f, h, p, K)
g = gf_rem(g, f, p, K)
b = gf_frobenius_monomial_base(f, p, K)
i += 1
if f != [K.one]:
return factors + [(f, gf_degree(f))]
else:
return factors
def gf_edf_zassenhaus(f, n, p, K):
"""
Cantor-Zassenhaus: Probabilistic Equal Degree Factorization
Given a monic square-free polynomial ``f`` in ``GF(p)[x]`` and
an integer ``n``, such that ``n`` divides ``deg(f)``, returns all
irreducible factors ``f_1,...,f_d`` of ``f``, each of degree ``n``.
EDF procedure gives complete factorization over Galois fields.
Consider the square-free polynomial ``f = x**3 + x**2 + x + 1`` in
``GF(5)[x]``. Let's compute its irreducible factors of degree one::
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_edf_zassenhaus
>>> gf_edf_zassenhaus([1,1,1,1], 1, 5, ZZ)
[[1, 1], [1, 2], [1, 3]]
Notes
=====
The case p == 2 is handled by Cohen's Algorithm 3.4.8. The case p odd is
as in Geddes Algorithm 8.9 (or Cohen's Algorithm 3.4.6).
References
==========
.. [1] [Gathen99]_
.. [2] [Geddes92]_ Algorithm 8.9
.. [3] [Cohen93]_ Algorithm 3.4.8
"""
factors = [f]
if gf_degree(f) <= n:
return factors
N = gf_degree(f) // n
if p != 2:
b = gf_frobenius_monomial_base(f, p, K)
t = [K.one, K.zero]
while len(factors) < N:
if p == 2:
h = r = t
for i in range(n - 1):
r = gf_pow_mod(r, 2, f, p, K)
h = gf_add(h, r, p, K)
g = gf_gcd(f, h, p, K)
t += [K.zero, K.zero]
else:
r = gf_random(2 * n - 1, p, K)
h = _gf_pow_pnm1d2(r, n, f, b, p, K)
g = gf_gcd(f, gf_sub_ground(h, K.one, p, K), p, K)
if g != [K.one] and g != f:
factors = gf_edf_zassenhaus(g, n, p, K) \
+ gf_edf_zassenhaus(gf_quo(f, g, p, K), n, p, K)
return _sort_factors(factors, multiple=False)
def gf_ddf_shoup(f, p, K):
"""
Kaltofen-Shoup: Deterministic Distinct Degree Factorization
Given a monic square-free polynomial ``f`` in ``GF(p)[x]``, computes
partial distinct degree factorization ``f_1,...,f_d`` of ``f`` where
``deg(f_i) != deg(f_j)`` for ``i != j``. The result is returned as a
list of pairs ``(f_i, e_i)`` where ``deg(f_i) > 0`` and ``e_i > 0``
is an argument to the equal degree factorization routine.
This algorithm is an improved version of Zassenhaus algorithm for
large ``deg(f)`` and modulus ``p`` (especially for ``deg(f) ~ lg(p)``).
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_ddf_shoup, gf_from_dict
>>> f = gf_from_dict({6: ZZ(1), 5: ZZ(-1), 4: ZZ(1), 3: ZZ(1), 1: ZZ(-1)}, 3, ZZ)
>>> gf_ddf_shoup(f, 3, ZZ)
[([1, 1, 0], 1), ([1, 1, 0, 1, 2], 2)]
References
==========
.. [1] [Kaltofen98]_
.. [2] [Shoup95]_
.. [3] [Gathen92]_
"""
n = gf_degree(f)
k = int(_ceil(_sqrt(n//2)))
b = gf_frobenius_monomial_base(f, p, K)
h = gf_frobenius_map([K.one, K.zero], f, b, p, K)
# U[i] = x**(p**i)
U = [[K.one, K.zero], h] + [K.zero]*(k - 1)
for i in range(2, k + 1):
U[i] = gf_frobenius_map(U[i-1], f, b, p, K)
h, U = U[k], U[:k]
# V[i] = x**(p**(k*(i+1)))
V = [h] + [K.zero]*(k - 1)
for i in range(1, k):
V[i] = gf_compose_mod(V[i - 1], h, f, p, K)
factors = []
for i, v in enumerate(V):
h, j = [K.one], k - 1
for u in U:
g = gf_sub(v, u, p, K)
h = gf_mul(h, g, p, K)
h = gf_rem(h, f, p, K)
g = gf_gcd(f, h, p, K)
f = gf_quo(f, g, p, K)
for u in reversed(U):
h = gf_sub(v, u, p, K)
F = gf_gcd(g, h, p, K)
if F != [K.one]:
factors.append((F, k*(i + 1) - j))
g, j = gf_quo(g, F, p, K), j - 1
if f != [K.one]:
factors.append((f, gf_degree(f)))
return factors
def gf_edf_shoup(f, n, p, K):
"""
Gathen-Shoup: Probabilistic Equal Degree Factorization
Given a monic square-free polynomial ``f`` in ``GF(p)[x]`` and integer
``n`` such that ``n`` divides ``deg(f)``, returns all irreducible factors
``f_1,...,f_d`` of ``f``, each of degree ``n``. This is a complete
factorization over Galois fields.
This algorithm is an improved version of Zassenhaus algorithm for
large ``deg(f)`` and modulus ``p`` (especially for ``deg(f) ~ lg(p)``).
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_edf_shoup
>>> gf_edf_shoup(ZZ.map([1, 2837, 2277]), 1, 2917, ZZ)
[[1, 852], [1, 1985]]
References
==========
.. [1] [Shoup91]_
.. [2] [Gathen92]_
"""
N, q = gf_degree(f), int(p)
if not N:
return []
if N <= n:
return [f]
factors, x = [f], [K.one, K.zero]
r = gf_random(N - 1, p, K)
if p == 2:
h = gf_pow_mod(x, q, f, p, K)
H = gf_trace_map(r, h, x, n - 1, f, p, K)[1]
h1 = gf_gcd(f, H, p, K)
h2 = gf_quo(f, h1, p, K)
factors = gf_edf_shoup(h1, n, p, K) \
+ gf_edf_shoup(h2, n, p, K)
else:
b = gf_frobenius_monomial_base(f, p, K)
H = _gf_trace_map(r, n, f, b, p, K)
h = gf_pow_mod(H, (q - 1)//2, f, p, K)
h1 = gf_gcd(f, h, p, K)
h2 = gf_gcd(f, gf_sub_ground(h, K.one, p, K), p, K)
h3 = gf_quo(f, gf_mul(h1, h2, p, K), p, K)
factors = gf_edf_shoup(h1, n, p, K) \
+ gf_edf_shoup(h2, n, p, K) \
+ gf_edf_shoup(h3, n, p, K)
return _sort_factors(factors, multiple=False)
def gf_zassenhaus(f, p, K):
"""
Factor a square-free ``f`` in ``GF(p)[x]`` for medium ``p``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_zassenhaus
>>> gf_zassenhaus(ZZ.map([1, 4, 3]), 5, ZZ)
[[1, 1], [1, 3]]
"""
factors = []
for factor, n in gf_ddf_zassenhaus(f, p, K):
factors += gf_edf_zassenhaus(factor, n, p, K)
return _sort_factors(factors, multiple=False)
def gf_shoup(f, p, K):
"""
Factor a square-free ``f`` in ``GF(p)[x]`` for large ``p``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_shoup
>>> gf_shoup(ZZ.map([1, 4, 3]), 5, ZZ)
[[1, 1], [1, 3]]
"""
factors = []
for factor, n in gf_ddf_shoup(f, p, K):
factors += gf_edf_shoup(factor, n, p, K)
return _sort_factors(factors, multiple=False)
_factor_methods = {
'berlekamp': gf_berlekamp, # ``p`` : small
'zassenhaus': gf_zassenhaus, # ``p`` : medium
'shoup': gf_shoup, # ``p`` : large
}
def gf_factor_sqf(f, p, K, method=None):
"""
Factor a square-free polynomial ``f`` in ``GF(p)[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_factor_sqf
>>> gf_factor_sqf(ZZ.map([3, 2, 4]), 5, ZZ)
(3, [[1, 1], [1, 3]])
"""
lc, f = gf_monic(f, p, K)
if gf_degree(f) < 1:
return lc, []
method = method or query('GF_FACTOR_METHOD')
if method is not None:
factors = _factor_methods[method](f, p, K)
else:
factors = gf_zassenhaus(f, p, K)
return lc, factors
def gf_factor(f, p, K):
"""
Factor (non square-free) polynomials in ``GF(p)[x]``.
Given a possibly non square-free polynomial ``f`` in ``GF(p)[x]``,
returns its complete factorization into irreducibles::
f_1(x)**e_1 f_2(x)**e_2 ... f_d(x)**e_d
where each ``f_i`` is a monic polynomial and ``gcd(f_i, f_j) == 1``,
for ``i != j``. The result is given as a tuple consisting of the
leading coefficient of ``f`` and a list of factors of ``f`` with
their multiplicities.
The algorithm proceeds by first computing square-free decomposition
of ``f`` and then iteratively factoring each of square-free factors.
Consider a non square-free polynomial ``f = (7*x + 1) (x + 2)**2`` in
``GF(11)[x]``. We obtain its factorization into irreducibles as follows::
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.galoistools import gf_factor
>>> gf_factor(ZZ.map([5, 2, 7, 2]), 11, ZZ)
(5, [([1, 2], 1), ([1, 8], 2)])
We arrived with factorization ``f = 5 (x + 2) (x + 8)**2``. We did not
recover the exact form of the input polynomial because we requested to
get monic factors of ``f`` and its leading coefficient separately.
Square-free factors of ``f`` can be factored into irreducibles over
``GF(p)`` using three very different methods:
Berlekamp
efficient for very small values of ``p`` (usually ``p < 25``)
Cantor-Zassenhaus
efficient on average input and with "typical" ``p``
Shoup-Kaltofen-Gathen
efficient with very large inputs and modulus
If you want to use a specific factorization method, instead of the default
one, set ``GF_FACTOR_METHOD`` with one of ``berlekamp``, ``zassenhaus`` or
``shoup`` values.
References
==========
.. [1] [Gathen99]_
"""
lc, f = gf_monic(f, p, K)
if gf_degree(f) < 1:
return lc, []
factors = []
for g, n in gf_sqf_list(f, p, K)[1]:
for h in gf_factor_sqf(g, p, K)[1]:
factors.append((h, n))
return lc, _sort_factors(factors)
def gf_value(f, a):
"""
Value of polynomial 'f' at 'a' in field R.
Examples
========
>>> from sympy.polys.galoistools import gf_value
>>> gf_value([1, 7, 2, 4], 11)
2204
"""
result = 0
for c in f:
result *= a
result += c
return result
def linear_congruence(a, b, m):
"""
Returns the values of x satisfying a*x congruent b mod(m)
Here m is positive integer and a, b are natural numbers.
This function returns only those values of x which are distinct mod(m).
Examples
========
>>> from sympy.polys.galoistools import linear_congruence
>>> linear_congruence(3, 12, 15)
[4, 9, 14]
There are 3 solutions distinct mod(15) since gcd(a, m) = gcd(3, 15) = 3.
References
==========
.. [1] https://en.wikipedia.org/wiki/Linear_congruence_theorem
"""
from sympy.polys.polytools import gcdex
if a % m == 0:
if b % m == 0:
return list(range(m))
else:
return []
r, _, g = gcdex(a, m)
if b % g != 0:
return []
return [(r * b // g + t * m // g) % m for t in range(g)]
def _raise_mod_power(x, s, p, f):
"""
Used in gf_csolve to generate solutions of f(x) cong 0 mod(p**(s + 1))
from the solutions of f(x) cong 0 mod(p**s).
Examples
========
>>> from sympy.polys.galoistools import _raise_mod_power
>>> from sympy.polys.galoistools import csolve_prime
These is the solutions of f(x) = x**2 + x + 7 cong 0 mod(3)
>>> f = [1, 1, 7]
>>> csolve_prime(f, 3)
[1]
>>> [ i for i in range(3) if not (i**2 + i + 7) % 3]
[1]
The solutions of f(x) cong 0 mod(9) are constructed from the
values returned from _raise_mod_power:
>>> x, s, p = 1, 1, 3
>>> V = _raise_mod_power(x, s, p, f)
>>> [x + v * p**s for v in V]
[1, 4, 7]
And these are confirmed with the following:
>>> [ i for i in range(3**2) if not (i**2 + i + 7) % 3**2]
[1, 4, 7]
"""
from sympy.polys.domains import ZZ
f_f = gf_diff(f, p, ZZ)
alpha = gf_value(f_f, x)
beta = - gf_value(f, x) // p**s
return linear_congruence(alpha, beta, p)
def _csolve_prime_las_vegas(f, p, seed=None):
r""" Solutions of `f(x) \equiv 0 \pmod{p}`, `f(0) \not\equiv 0 \pmod{p}`.
Explanation
===========
This algorithm is classified as the Las Vegas method.
That is, it always returns the correct answer and solves the problem
fast in many cases, but if it is unlucky, it does not answer forever.
Suppose the polynomial f is not a zero polynomial. Assume further
that it is of degree at most p-1 and `f(0)\not\equiv 0 \pmod{p}`.
These assumptions are not an essential part of the algorithm,
only that it is more convenient for the function calling this
function to resolve them.
Note that `x^{p-1} - 1 \equiv \prod_{a=1}^{p-1}(x - a) \pmod{p}`.
Thus, the greatest common divisor with f is `\prod_{s \in S}(x - s)`,
with S being the set of solutions to f. Furthermore,
when a is randomly determined, `(x+a)^{(p-1)/2}-1` is
a polynomial with (p-1)/2 randomly chosen solutions.
The greatest common divisor of f may be a nontrivial factor of f.
When p is large and the degree of f is small,
it is faster than naive solution methods.
Parameters
==========
f : polynomial
p : prime number
Returns
=======
list[int]
a list of solutions, sorted in ascending order
by integers in the range [1, p). The same value
does not exist in the list even if there is
a multiple solution. If no solution exists, returns [].
Examples
========
>>> from sympy.polys.galoistools import _csolve_prime_las_vegas
>>> _csolve_prime_las_vegas([1, 4, 3], 7) # x^2 + 4x + 3 = 0 (mod 7)
[4, 6]
>>> _csolve_prime_las_vegas([5, 7, 1, 9], 11) # 5x^3 + 7x^2 + x + 9 = 0 (mod 11)
[1, 5, 8]
References
==========
.. [1] R. Crandall and C. Pomerance "Prime Numbers", 2nd Ed., Algorithm 2.3.10
"""
from sympy.polys.domains import ZZ
from sympy.ntheory import sqrt_mod
randint = _randint(seed)
root = set()
g = gf_pow_mod([1, 0], p - 1, f, p, ZZ)
g = gf_sub_ground(g, 1, p, ZZ)
# We want to calculate gcd(x**(p-1) - 1, f(x))
factors = [gf_gcd(f, g, p, ZZ)]
while factors:
f = factors.pop()
# If the degree is small, solve directly
if len(f) <= 1:
continue
if len(f) == 2:
root.add(-invert(f[0], p) * f[1] % p)
continue
if len(f) == 3:
inv = invert(f[0], p)
b = f[1] * inv % p
b = (b + p * (b % 2)) // 2
root.update((r - b) % p for r in
sqrt_mod(b**2 - f[2] * inv, p, all_roots=True))
continue
while True:
# Determine `a` randomly and
# compute gcd((x+a)**((p-1)//2)-1, f(x))
a = randint(0, p - 1)
g = gf_pow_mod([1, a], (p - 1) // 2, f, p, ZZ)
g = gf_sub_ground(g, 1, p, ZZ)
g = gf_gcd(f, g, p, ZZ)
if 1 < len(g) < len(f):
factors.append(g)
factors.append(gf_div(f, g, p, ZZ)[0])
break
return sorted(root)
def csolve_prime(f, p, e=1):
r""" Solutions of `f(x) \equiv 0 \pmod{p^e}`.
Parameters
==========
f : polynomial
p : prime number
e : positive integer
Returns
=======
list[int]
a list of solutions, sorted in ascending order
by integers in the range [1, p**e). The same value
does not exist in the list even if there is
a multiple solution. If no solution exists, returns [].
Examples
========
>>> from sympy.polys.galoistools import csolve_prime
>>> csolve_prime([1, 1, 7], 3, 1)
[1]
>>> csolve_prime([1, 1, 7], 3, 2)
[1, 4, 7]
Solutions [7, 4, 1] (mod 3**2) are generated by ``_raise_mod_power()``
from solution [1] (mod 3).
"""
from sympy.polys.domains import ZZ
g = [MPZ(int(c)) for c in f]
# Convert to polynomial of degree at most p-1
for i in range(len(g) - p):
g[i + p - 1] += g[i]
g[i] = 0
g = gf_trunc(g, p)
# Checks whether g(x) is divisible by x
k = 0
while k < len(g) and g[len(g) - k - 1] == 0:
k += 1
if k:
g = g[:-k]
root_zero = [0]
else:
root_zero = []
if g == []:
X1 = list(range(p))
elif len(g)**2 < p:
# The conditions under which `_csolve_prime_las_vegas` is faster than
# a naive solution are worth considering.
X1 = root_zero + _csolve_prime_las_vegas(g, p)
else:
X1 = root_zero + [i for i in range(p) if gf_eval(g, i, p, ZZ) == 0]
if e == 1:
return X1
X = []
S = list(zip(X1, [1]*len(X1)))
while S:
x, s = S.pop()
if s == e:
X.append(x)
else:
s1 = s + 1
ps = p**s
S.extend([(x + v*ps, s1) for v in _raise_mod_power(x, s, p, f)])
return sorted(X)
def gf_csolve(f, n):
"""
To solve f(x) congruent 0 mod(n).
n is divided into canonical factors and f(x) cong 0 mod(p**e) will be
solved for each factor. Applying the Chinese Remainder Theorem to the
results returns the final answers.
Examples
========
Solve [1, 1, 7] congruent 0 mod(189):
>>> from sympy.polys.galoistools import gf_csolve
>>> gf_csolve([1, 1, 7], 189)
[13, 49, 76, 112, 139, 175]
See Also
========
sympy.ntheory.residue_ntheory.polynomial_congruence : a higher level solving routine
References
==========
.. [1] 'An introduction to the Theory of Numbers' 5th Edition by Ivan Niven,
Zuckerman and Montgomery.
"""
from sympy.polys.domains import ZZ
from sympy.ntheory import factorint
P = factorint(n)
X = [csolve_prime(f, p, e) for p, e in P.items()]
pools = list(map(tuple, X))
perms = [[]]
for pool in pools:
perms = [x + [y] for x in perms for y in pool]
dist_factors = [pow(p, e) for p, e in P.items()]
return sorted([gf_crt(per, dist_factors, ZZ) for per in perms])
PK ]ZZZ��L�.[ .[ sympy/polys/groebnertools.py"""Groebner bases algorithms. """
from sympy.core.symbol import Dummy
from sympy.polys.monomials import monomial_mul, monomial_lcm, monomial_divides, term_div
from sympy.polys.orderings import lex
from sympy.polys.polyerrors import DomainError
from sympy.polys.polyconfig import query
def groebner(seq, ring, method=None):
"""
Computes Groebner basis for a set of polynomials in `K[X]`.
Wrapper around the (default) improved Buchberger and the other algorithms
for computing Groebner bases. The choice of algorithm can be changed via
``method`` argument or :func:`sympy.polys.polyconfig.setup`, where
``method`` can be either ``buchberger`` or ``f5b``.
"""
if method is None:
method = query('groebner')
_groebner_methods = {
'buchberger': _buchberger,
'f5b': _f5b,
}
try:
_groebner = _groebner_methods[method]
except KeyError:
raise ValueError("'%s' is not a valid Groebner bases algorithm (valid are 'buchberger' and 'f5b')" % method)
domain, orig = ring.domain, None
if not domain.is_Field or not domain.has_assoc_Field:
try:
orig, ring = ring, ring.clone(domain=domain.get_field())
except DomainError:
raise DomainError("Cannot compute a Groebner basis over %s" % domain)
else:
seq = [ s.set_ring(ring) for s in seq ]
G = _groebner(seq, ring)
if orig is not None:
G = [ g.clear_denoms()[1].set_ring(orig) for g in G ]
return G
def _buchberger(f, ring):
"""
Computes Groebner basis for a set of polynomials in `K[X]`.
Given a set of multivariate polynomials `F`, finds another
set `G`, such that Ideal `F = Ideal G` and `G` is a reduced
Groebner basis.
The resulting basis is unique and has monic generators if the
ground domains is a field. Otherwise the result is non-unique
but Groebner bases over e.g. integers can be computed (if the
input polynomials are monic).
Groebner bases can be used to choose specific generators for a
polynomial ideal. Because these bases are unique you can check
for ideal equality by comparing the Groebner bases. To see if
one polynomial lies in an ideal, divide by the elements in the
base and see if the remainder vanishes.
They can also be used to solve systems of polynomial equations
as, by choosing lexicographic ordering, you can eliminate one
variable at a time, provided that the ideal is zero-dimensional
(finite number of solutions).
Notes
=====
Algorithm used: an improved version of Buchberger's algorithm
as presented in T. Becker, V. Weispfenning, Groebner Bases: A
Computational Approach to Commutative Algebra, Springer, 1993,
page 232.
References
==========
.. [1] [Bose03]_
.. [2] [Giovini91]_
.. [3] [Ajwa95]_
.. [4] [Cox97]_
"""
order = ring.order
monomial_mul = ring.monomial_mul
monomial_div = ring.monomial_div
monomial_lcm = ring.monomial_lcm
def select(P):
# normal selection strategy
# select the pair with minimum LCM(LM(f), LM(g))
pr = min(P, key=lambda pair: order(monomial_lcm(f[pair[0]].LM, f[pair[1]].LM)))
return pr
def normal(g, J):
h = g.rem([ f[j] for j in J ])
if not h:
return None
else:
h = h.monic()
if h not in I:
I[h] = len(f)
f.append(h)
return h.LM, I[h]
def update(G, B, ih):
# update G using the set of critical pairs B and h
# [BW] page 230
h = f[ih]
mh = h.LM
# filter new pairs (h, g), g in G
C = G.copy()
D = set()
while C:
# select a pair (h, g) by popping an element from C
ig = C.pop()
g = f[ig]
mg = g.LM
LCMhg = monomial_lcm(mh, mg)
def lcm_divides(ip):
# LCM(LM(h), LM(p)) divides LCM(LM(h), LM(g))
m = monomial_lcm(mh, f[ip].LM)
return monomial_div(LCMhg, m)
# HT(h) and HT(g) disjoint: mh*mg == LCMhg
if monomial_mul(mh, mg) == LCMhg or (
not any(lcm_divides(ipx) for ipx in C) and
not any(lcm_divides(pr[1]) for pr in D)):
D.add((ih, ig))
E = set()
while D:
# select h, g from D (h the same as above)
ih, ig = D.pop()
mg = f[ig].LM
LCMhg = monomial_lcm(mh, mg)
if not monomial_mul(mh, mg) == LCMhg:
E.add((ih, ig))
# filter old pairs
B_new = set()
while B:
# select g1, g2 from B (-> CP)
ig1, ig2 = B.pop()
mg1 = f[ig1].LM
mg2 = f[ig2].LM
LCM12 = monomial_lcm(mg1, mg2)
# if HT(h) does not divide lcm(HT(g1), HT(g2))
if not monomial_div(LCM12, mh) or \
monomial_lcm(mg1, mh) == LCM12 or \
monomial_lcm(mg2, mh) == LCM12:
B_new.add((ig1, ig2))
B_new |= E
# filter polynomials
G_new = set()
while G:
ig = G.pop()
mg = f[ig].LM
if not monomial_div(mg, mh):
G_new.add(ig)
G_new.add(ih)
return G_new, B_new
# end of update ################################
if not f:
return []
# replace f with a reduced list of initial polynomials; see [BW] page 203
f1 = f[:]
while True:
f = f1[:]
f1 = []
for i in range(len(f)):
p = f[i]
r = p.rem(f[:i])
if r:
f1.append(r.monic())
if f == f1:
break
I = {} # ip = I[p]; p = f[ip]
F = set() # set of indices of polynomials
G = set() # set of indices of intermediate would-be Groebner basis
CP = set() # set of pairs of indices of critical pairs
for i, h in enumerate(f):
I[h] = i
F.add(i)
#####################################
# algorithm GROEBNERNEWS2 in [BW] page 232
while F:
# select p with minimum monomial according to the monomial ordering
h = min([f[x] for x in F], key=lambda f: order(f.LM))
ih = I[h]
F.remove(ih)
G, CP = update(G, CP, ih)
# count the number of critical pairs which reduce to zero
reductions_to_zero = 0
while CP:
ig1, ig2 = select(CP)
CP.remove((ig1, ig2))
h = spoly(f[ig1], f[ig2], ring)
# ordering divisors is on average more efficient [Cox] page 111
G1 = sorted(G, key=lambda g: order(f[g].LM))
ht = normal(h, G1)
if ht:
G, CP = update(G, CP, ht[1])
else:
reductions_to_zero += 1
######################################
# now G is a Groebner basis; reduce it
Gr = set()
for ig in G:
ht = normal(f[ig], G - {ig})
if ht:
Gr.add(ht[1])
Gr = [f[ig] for ig in Gr]
# order according to the monomial ordering
Gr = sorted(Gr, key=lambda f: order(f.LM), reverse=True)
return Gr
def spoly(p1, p2, ring):
"""
Compute LCM(LM(p1), LM(p2))/LM(p1)*p1 - LCM(LM(p1), LM(p2))/LM(p2)*p2
This is the S-poly provided p1 and p2 are monic
"""
LM1 = p1.LM
LM2 = p2.LM
LCM12 = ring.monomial_lcm(LM1, LM2)
m1 = ring.monomial_div(LCM12, LM1)
m2 = ring.monomial_div(LCM12, LM2)
s1 = p1.mul_monom(m1)
s2 = p2.mul_monom(m2)
s = s1 - s2
return s
# F5B
# convenience functions
def Sign(f):
return f[0]
def Polyn(f):
return f[1]
def Num(f):
return f[2]
def sig(monomial, index):
return (monomial, index)
def lbp(signature, polynomial, number):
return (signature, polynomial, number)
# signature functions
def sig_cmp(u, v, order):
"""
Compare two signatures by extending the term order to K[X]^n.
u < v iff
- the index of v is greater than the index of u
or
- the index of v is equal to the index of u and u[0] < v[0] w.r.t. order
u > v otherwise
"""
if u[1] > v[1]:
return -1
if u[1] == v[1]:
#if u[0] == v[0]:
# return 0
if order(u[0]) < order(v[0]):
return -1
return 1
def sig_key(s, order):
"""
Key for comparing two signatures.
s = (m, k), t = (n, l)
s < t iff [k > l] or [k == l and m < n]
s > t otherwise
"""
return (-s[1], order(s[0]))
def sig_mult(s, m):
"""
Multiply a signature by a monomial.
The product of a signature (m, i) and a monomial n is defined as
(m * t, i).
"""
return sig(monomial_mul(s[0], m), s[1])
# labeled polynomial functions
def lbp_sub(f, g):
"""
Subtract labeled polynomial g from f.
The signature and number of the difference of f and g are signature
and number of the maximum of f and g, w.r.t. lbp_cmp.
"""
if sig_cmp(Sign(f), Sign(g), Polyn(f).ring.order) < 0:
max_poly = g
else:
max_poly = f
ret = Polyn(f) - Polyn(g)
return lbp(Sign(max_poly), ret, Num(max_poly))
def lbp_mul_term(f, cx):
"""
Multiply a labeled polynomial with a term.
The product of a labeled polynomial (s, p, k) by a monomial is
defined as (m * s, m * p, k).
"""
return lbp(sig_mult(Sign(f), cx[0]), Polyn(f).mul_term(cx), Num(f))
def lbp_cmp(f, g):
"""
Compare two labeled polynomials.
f < g iff
- Sign(f) < Sign(g)
or
- Sign(f) == Sign(g) and Num(f) > Num(g)
f > g otherwise
"""
if sig_cmp(Sign(f), Sign(g), Polyn(f).ring.order) == -1:
return -1
if Sign(f) == Sign(g):
if Num(f) > Num(g):
return -1
#if Num(f) == Num(g):
# return 0
return 1
def lbp_key(f):
"""
Key for comparing two labeled polynomials.
"""
return (sig_key(Sign(f), Polyn(f).ring.order), -Num(f))
# algorithm and helper functions
def critical_pair(f, g, ring):
"""
Compute the critical pair corresponding to two labeled polynomials.
A critical pair is a tuple (um, f, vm, g), where um and vm are
terms such that um * f - vm * g is the S-polynomial of f and g (so,
wlog assume um * f > vm * g).
For performance sake, a critical pair is represented as a tuple
(Sign(um * f), um, f, Sign(vm * g), vm, g), since um * f creates
a new, relatively expensive object in memory, whereas Sign(um *
f) and um are lightweight and f (in the tuple) is a reference to
an already existing object in memory.
"""
domain = ring.domain
ltf = Polyn(f).LT
ltg = Polyn(g).LT
lt = (monomial_lcm(ltf[0], ltg[0]), domain.one)
um = term_div(lt, ltf, domain)
vm = term_div(lt, ltg, domain)
# The full information is not needed (now), so only the product
# with the leading term is considered:
fr = lbp_mul_term(lbp(Sign(f), Polyn(f).leading_term(), Num(f)), um)
gr = lbp_mul_term(lbp(Sign(g), Polyn(g).leading_term(), Num(g)), vm)
# return in proper order, such that the S-polynomial is just
# u_first * f_first - u_second * f_second:
if lbp_cmp(fr, gr) == -1:
return (Sign(gr), vm, g, Sign(fr), um, f)
else:
return (Sign(fr), um, f, Sign(gr), vm, g)
def cp_cmp(c, d):
"""
Compare two critical pairs c and d.
c < d iff
- lbp(c[0], _, Num(c[2]) < lbp(d[0], _, Num(d[2])) (this
corresponds to um_c * f_c and um_d * f_d)
or
- lbp(c[0], _, Num(c[2]) >< lbp(d[0], _, Num(d[2])) and
lbp(c[3], _, Num(c[5])) < lbp(d[3], _, Num(d[5])) (this
corresponds to vm_c * g_c and vm_d * g_d)
c > d otherwise
"""
zero = Polyn(c[2]).ring.zero
c0 = lbp(c[0], zero, Num(c[2]))
d0 = lbp(d[0], zero, Num(d[2]))
r = lbp_cmp(c0, d0)
if r == -1:
return -1
if r == 0:
c1 = lbp(c[3], zero, Num(c[5]))
d1 = lbp(d[3], zero, Num(d[5]))
r = lbp_cmp(c1, d1)
if r == -1:
return -1
#if r == 0:
# return 0
return 1
def cp_key(c, ring):
"""
Key for comparing critical pairs.
"""
return (lbp_key(lbp(c[0], ring.zero, Num(c[2]))), lbp_key(lbp(c[3], ring.zero, Num(c[5]))))
def s_poly(cp):
"""
Compute the S-polynomial of a critical pair.
The S-polynomial of a critical pair cp is cp[1] * cp[2] - cp[4] * cp[5].
"""
return lbp_sub(lbp_mul_term(cp[2], cp[1]), lbp_mul_term(cp[5], cp[4]))
def is_rewritable_or_comparable(sign, num, B):
"""
Check if a labeled polynomial is redundant by checking if its
signature and number imply rewritability or comparability.
(sign, num) is comparable if there exists a labeled polynomial
h in B, such that sign[1] (the index) is less than Sign(h)[1]
and sign[0] is divisible by the leading monomial of h.
(sign, num) is rewritable if there exists a labeled polynomial
h in B, such thatsign[1] is equal to Sign(h)[1], num < Num(h)
and sign[0] is divisible by Sign(h)[0].
"""
for h in B:
# comparable
if sign[1] < Sign(h)[1]:
if monomial_divides(Polyn(h).LM, sign[0]):
return True
# rewritable
if sign[1] == Sign(h)[1]:
if num < Num(h):
if monomial_divides(Sign(h)[0], sign[0]):
return True
return False
def f5_reduce(f, B):
"""
F5-reduce a labeled polynomial f by B.
Continuously searches for non-zero labeled polynomial h in B, such
that the leading term lt_h of h divides the leading term lt_f of
f and Sign(lt_h * h) < Sign(f). If such a labeled polynomial h is
found, f gets replaced by f - lt_f / lt_h * h. If no such h can be
found or f is 0, f is no further F5-reducible and f gets returned.
A polynomial that is reducible in the usual sense need not be
F5-reducible, e.g.:
>>> from sympy.polys.groebnertools import lbp, sig, f5_reduce, Polyn
>>> from sympy.polys import ring, QQ, lex
>>> R, x,y,z = ring("x,y,z", QQ, lex)
>>> f = lbp(sig((1, 1, 1), 4), x, 3)
>>> g = lbp(sig((0, 0, 0), 2), x, 2)
>>> Polyn(f).rem([Polyn(g)])
0
>>> f5_reduce(f, [g])
(((1, 1, 1), 4), x, 3)
"""
order = Polyn(f).ring.order
domain = Polyn(f).ring.domain
if not Polyn(f):
return f
while True:
g = f
for h in B:
if Polyn(h):
if monomial_divides(Polyn(h).LM, Polyn(f).LM):
t = term_div(Polyn(f).LT, Polyn(h).LT, domain)
if sig_cmp(sig_mult(Sign(h), t[0]), Sign(f), order) < 0:
# The following check need not be done and is in general slower than without.
#if not is_rewritable_or_comparable(Sign(gp), Num(gp), B):
hp = lbp_mul_term(h, t)
f = lbp_sub(f, hp)
break
if g == f or not Polyn(f):
return f
def _f5b(F, ring):
"""
Computes a reduced Groebner basis for the ideal generated by F.
f5b is an implementation of the F5B algorithm by Yao Sun and
Dingkang Wang. Similarly to Buchberger's algorithm, the algorithm
proceeds by computing critical pairs, computing the S-polynomial,
reducing it and adjoining the reduced S-polynomial if it is not 0.
Unlike Buchberger's algorithm, each polynomial contains additional
information, namely a signature and a number. The signature
specifies the path of computation (i.e. from which polynomial in
the original basis was it derived and how), the number says when
the polynomial was added to the basis. With this information it
is (often) possible to decide if an S-polynomial will reduce to
0 and can be discarded.
Optimizations include: Reducing the generators before computing
a Groebner basis, removing redundant critical pairs when a new
polynomial enters the basis and sorting the critical pairs and
the current basis.
Once a Groebner basis has been found, it gets reduced.
References
==========
.. [1] Yao Sun, Dingkang Wang: "A New Proof for the Correctness of F5
(F5-Like) Algorithm", https://arxiv.org/abs/1004.0084 (specifically
v4)
.. [2] Thomas Becker, Volker Weispfenning, Groebner bases: A computational
approach to commutative algebra, 1993, p. 203, 216
"""
order = ring.order
# reduce polynomials (like in Mario Pernici's implementation) (Becker, Weispfenning, p. 203)
B = F
while True:
F = B
B = []
for i in range(len(F)):
p = F[i]
r = p.rem(F[:i])
if r:
B.append(r)
if F == B:
break
# basis
B = [lbp(sig(ring.zero_monom, i + 1), F[i], i + 1) for i in range(len(F))]
B.sort(key=lambda f: order(Polyn(f).LM), reverse=True)
# critical pairs
CP = [critical_pair(B[i], B[j], ring) for i in range(len(B)) for j in range(i + 1, len(B))]
CP.sort(key=lambda cp: cp_key(cp, ring), reverse=True)
k = len(B)
reductions_to_zero = 0
while len(CP):
cp = CP.pop()
# discard redundant critical pairs:
if is_rewritable_or_comparable(cp[0], Num(cp[2]), B):
continue
if is_rewritable_or_comparable(cp[3], Num(cp[5]), B):
continue
s = s_poly(cp)
p = f5_reduce(s, B)
p = lbp(Sign(p), Polyn(p).monic(), k + 1)
if Polyn(p):
# remove old critical pairs, that become redundant when adding p:
indices = []
for i, cp in enumerate(CP):
if is_rewritable_or_comparable(cp[0], Num(cp[2]), [p]):
indices.append(i)
elif is_rewritable_or_comparable(cp[3], Num(cp[5]), [p]):
indices.append(i)
for i in reversed(indices):
del CP[i]
# only add new critical pairs that are not made redundant by p:
for g in B:
if Polyn(g):
cp = critical_pair(p, g, ring)
if is_rewritable_or_comparable(cp[0], Num(cp[2]), [p]):
continue
elif is_rewritable_or_comparable(cp[3], Num(cp[5]), [p]):
continue
CP.append(cp)
# sort (other sorting methods/selection strategies were not as successful)
CP.sort(key=lambda cp: cp_key(cp, ring), reverse=True)
# insert p into B:
m = Polyn(p).LM
if order(m) <= order(Polyn(B[-1]).LM):
B.append(p)
else:
for i, q in enumerate(B):
if order(m) > order(Polyn(q).LM):
B.insert(i, p)
break
k += 1
#print(len(B), len(CP), "%d critical pairs removed" % len(indices))
else:
reductions_to_zero += 1
# reduce Groebner basis:
H = [Polyn(g).monic() for g in B]
H = red_groebner(H, ring)
return sorted(H, key=lambda f: order(f.LM), reverse=True)
def red_groebner(G, ring):
"""
Compute reduced Groebner basis, from BeckerWeispfenning93, p. 216
Selects a subset of generators, that already generate the ideal
and computes a reduced Groebner basis for them.
"""
def reduction(P):
"""
The actual reduction algorithm.
"""
Q = []
for i, p in enumerate(P):
h = p.rem(P[:i] + P[i + 1:])
if h:
Q.append(h)
return [p.monic() for p in Q]
F = G
H = []
while F:
f0 = F.pop()
if not any(monomial_divides(f.LM, f0.LM) for f in F + H):
H.append(f0)
# Becker, Weispfenning, p. 217: H is Groebner basis of the ideal generated by G.
return reduction(H)
def is_groebner(G, ring):
"""
Check if G is a Groebner basis.
"""
for i in range(len(G)):
for j in range(i + 1, len(G)):
s = spoly(G[i], G[j], ring)
s = s.rem(G)
if s:
return False
return True
def is_minimal(G, ring):
"""
Checks if G is a minimal Groebner basis.
"""
order = ring.order
domain = ring.domain
G.sort(key=lambda g: order(g.LM))
for i, g in enumerate(G):
if g.LC != domain.one:
return False
for h in G[:i] + G[i + 1:]:
if monomial_divides(h.LM, g.LM):
return False
return True
def is_reduced(G, ring):
"""
Checks if G is a reduced Groebner basis.
"""
order = ring.order
domain = ring.domain
G.sort(key=lambda g: order(g.LM))
for i, g in enumerate(G):
if g.LC != domain.one:
return False
for term in g.terms():
for h in G[:i] + G[i + 1:]:
if monomial_divides(h.LM, term[0]):
return False
return True
def groebner_lcm(f, g):
"""
Computes LCM of two polynomials using Groebner bases.
The LCM is computed as the unique generator of the intersection
of the two ideals generated by `f` and `g`. The approach is to
compute a Groebner basis with respect to lexicographic ordering
of `t*f` and `(1 - t)*g`, where `t` is an unrelated variable and
then filtering out the solution that does not contain `t`.
References
==========
.. [1] [Cox97]_
"""
if f.ring != g.ring:
raise ValueError("Values should be equal")
ring = f.ring
domain = ring.domain
if not f or not g:
return ring.zero
if len(f) <= 1 and len(g) <= 1:
monom = monomial_lcm(f.LM, g.LM)
coeff = domain.lcm(f.LC, g.LC)
return ring.term_new(monom, coeff)
fc, f = f.primitive()
gc, g = g.primitive()
lcm = domain.lcm(fc, gc)
f_terms = [ ((1,) + monom, coeff) for monom, coeff in f.terms() ]
g_terms = [ ((0,) + monom, coeff) for monom, coeff in g.terms() ] \
+ [ ((1,) + monom,-coeff) for monom, coeff in g.terms() ]
t = Dummy("t")
t_ring = ring.clone(symbols=(t,) + ring.symbols, order=lex)
F = t_ring.from_terms(f_terms)
G = t_ring.from_terms(g_terms)
basis = groebner([F, G], t_ring)
def is_independent(h, j):
return not any(monom[j] for monom in h.monoms())
H = [ h for h in basis if is_independent(h, 0) ]
h_terms = [ (monom[1:], coeff*lcm) for monom, coeff in H[0].terms() ]
h = ring.from_terms(h_terms)
return h
def groebner_gcd(f, g):
"""Computes GCD of two polynomials using Groebner bases. """
if f.ring != g.ring:
raise ValueError("Values should be equal")
domain = f.ring.domain
if not domain.is_Field:
fc, f = f.primitive()
gc, g = g.primitive()
gcd = domain.gcd(fc, gc)
H = (f*g).quo([groebner_lcm(f, g)])
if len(H) != 1:
raise ValueError("Length should be 1")
h = H[0]
if not domain.is_Field:
return gcd*h
else:
return h.monic()
PK ]ZZZ��/Ӕ � sympy/polys/heuristicgcd.py"""Heuristic polynomial GCD algorithm (HEUGCD). """
from .polyerrors import HeuristicGCDFailed
HEU_GCD_MAX = 6
def heugcd(f, g):
"""
Heuristic polynomial GCD in ``Z[X]``.
Given univariate polynomials ``f`` and ``g`` in ``Z[X]``, returns
their GCD and cofactors, i.e. polynomials ``h``, ``cff`` and ``cfg``
such that::
h = gcd(f, g), cff = quo(f, h) and cfg = quo(g, h)
The algorithm is purely heuristic which means it may fail to compute
the GCD. This will be signaled by raising an exception. In this case
you will need to switch to another GCD method.
The algorithm computes the polynomial GCD by evaluating polynomials
``f`` and ``g`` at certain points and computing (fast) integer GCD
of those evaluations. The polynomial GCD is recovered from the integer
image by interpolation. The evaluation process reduces f and g variable
by variable into a large integer. The final step is to verify if the
interpolated polynomial is the correct GCD. This gives cofactors of
the input polynomials as a side effect.
Examples
========
>>> from sympy.polys.heuristicgcd import heugcd
>>> from sympy.polys import ring, ZZ
>>> R, x,y, = ring("x,y", ZZ)
>>> f = x**2 + 2*x*y + y**2
>>> g = x**2 + x*y
>>> h, cff, cfg = heugcd(f, g)
>>> h, cff, cfg
(x + y, x + y, x)
>>> cff*h == f
True
>>> cfg*h == g
True
References
==========
.. [1] [Liao95]_
"""
assert f.ring == g.ring and f.ring.domain.is_ZZ
ring = f.ring
x0 = ring.gens[0]
domain = ring.domain
gcd, f, g = f.extract_ground(g)
f_norm = f.max_norm()
g_norm = g.max_norm()
B = domain(2*min(f_norm, g_norm) + 29)
x = max(min(B, 99*domain.sqrt(B)),
2*min(f_norm // abs(f.LC),
g_norm // abs(g.LC)) + 4)
for i in range(0, HEU_GCD_MAX):
ff = f.evaluate(x0, x)
gg = g.evaluate(x0, x)
if ff and gg:
if ring.ngens == 1:
h, cff, cfg = domain.cofactors(ff, gg)
else:
h, cff, cfg = heugcd(ff, gg)
h = _gcd_interpolate(h, x, ring)
h = h.primitive()[1]
cff_, r = f.div(h)
if not r:
cfg_, r = g.div(h)
if not r:
h = h.mul_ground(gcd)
return h, cff_, cfg_
cff = _gcd_interpolate(cff, x, ring)
h, r = f.div(cff)
if not r:
cfg_, r = g.div(h)
if not r:
h = h.mul_ground(gcd)
return h, cff, cfg_
cfg = _gcd_interpolate(cfg, x, ring)
h, r = g.div(cfg)
if not r:
cff_, r = f.div(h)
if not r:
h = h.mul_ground(gcd)
return h, cff_, cfg
x = 73794*x * domain.sqrt(domain.sqrt(x)) // 27011
raise HeuristicGCDFailed('no luck')
def _gcd_interpolate(h, x, ring):
"""Interpolate polynomial GCD from integer GCD. """
f, i = ring.zero, 0
# TODO: don't expose poly repr implementation details
if ring.ngens == 1:
while h:
g = h % x
if g > x // 2: g -= x
h = (h - g) // x
# f += X**i*g
if g:
f[(i,)] = g
i += 1
else:
while h:
g = h.trunc_ground(x)
h = (h - g).quo_ground(x)
# f += X**i*g
if g:
for monom, coeff in g.iterterms():
f[(i,) + monom] = coeff
i += 1
if f.LC < 0:
return -f
else:
return f
PK ]ZZZ�ޣ L� L� sympy/polys/modulargcd.pyfrom sympy.core.symbol import Dummy
from sympy.ntheory import nextprime
from sympy.ntheory.modular import crt
from sympy.polys.domains import PolynomialRing
from sympy.polys.galoistools import (
gf_gcd, gf_from_dict, gf_gcdex, gf_div, gf_lcm)
from sympy.polys.polyerrors import ModularGCDFailed
from mpmath import sqrt
import random
def _trivial_gcd(f, g):
"""
Compute the GCD of two polynomials in trivial cases, i.e. when one
or both polynomials are zero.
"""
ring = f.ring
if not (f or g):
return ring.zero, ring.zero, ring.zero
elif not f:
if g.LC < ring.domain.zero:
return -g, ring.zero, -ring.one
else:
return g, ring.zero, ring.one
elif not g:
if f.LC < ring.domain.zero:
return -f, -ring.one, ring.zero
else:
return f, ring.one, ring.zero
return None
def _gf_gcd(fp, gp, p):
r"""
Compute the GCD of two univariate polynomials in `\mathbb{Z}_p[x]`.
"""
dom = fp.ring.domain
while gp:
rem = fp
deg = gp.degree()
lcinv = dom.invert(gp.LC, p)
while True:
degrem = rem.degree()
if degrem < deg:
break
rem = (rem - gp.mul_monom((degrem - deg,)).mul_ground(lcinv * rem.LC)).trunc_ground(p)
fp = gp
gp = rem
return fp.mul_ground(dom.invert(fp.LC, p)).trunc_ground(p)
def _degree_bound_univariate(f, g):
r"""
Compute an upper bound for the degree of the GCD of two univariate
integer polynomials `f` and `g`.
The function chooses a suitable prime `p` and computes the GCD of
`f` and `g` in `\mathbb{Z}_p[x]`. The choice of `p` guarantees that
the degree in `\mathbb{Z}_p[x]` is greater than or equal to the degree
in `\mathbb{Z}[x]`.
Parameters
==========
f : PolyElement
univariate integer polynomial
g : PolyElement
univariate integer polynomial
"""
gamma = f.ring.domain.gcd(f.LC, g.LC)
p = 1
p = nextprime(p)
while gamma % p == 0:
p = nextprime(p)
fp = f.trunc_ground(p)
gp = g.trunc_ground(p)
hp = _gf_gcd(fp, gp, p)
deghp = hp.degree()
return deghp
def _chinese_remainder_reconstruction_univariate(hp, hq, p, q):
r"""
Construct a polynomial `h_{pq}` in `\mathbb{Z}_{p q}[x]` such that
.. math ::
h_{pq} = h_p \; \mathrm{mod} \, p
h_{pq} = h_q \; \mathrm{mod} \, q
for relatively prime integers `p` and `q` and polynomials
`h_p` and `h_q` in `\mathbb{Z}_p[x]` and `\mathbb{Z}_q[x]`
respectively.
The coefficients of the polynomial `h_{pq}` are computed with the
Chinese Remainder Theorem. The symmetric representation in
`\mathbb{Z}_p[x]`, `\mathbb{Z}_q[x]` and `\mathbb{Z}_{p q}[x]` is used.
It is assumed that `h_p` and `h_q` have the same degree.
Parameters
==========
hp : PolyElement
univariate integer polynomial with coefficients in `\mathbb{Z}_p`
hq : PolyElement
univariate integer polynomial with coefficients in `\mathbb{Z}_q`
p : Integer
modulus of `h_p`, relatively prime to `q`
q : Integer
modulus of `h_q`, relatively prime to `p`
Examples
========
>>> from sympy.polys.modulargcd import _chinese_remainder_reconstruction_univariate
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> p = 3
>>> q = 5
>>> hp = -x**3 - 1
>>> hq = 2*x**3 - 2*x**2 + x
>>> hpq = _chinese_remainder_reconstruction_univariate(hp, hq, p, q)
>>> hpq
2*x**3 + 3*x**2 + 6*x + 5
>>> hpq.trunc_ground(p) == hp
True
>>> hpq.trunc_ground(q) == hq
True
"""
n = hp.degree()
x = hp.ring.gens[0]
hpq = hp.ring.zero
for i in range(n+1):
hpq[(i,)] = crt([p, q], [hp.coeff(x**i), hq.coeff(x**i)], symmetric=True)[0]
hpq.strip_zero()
return hpq
def modgcd_univariate(f, g):
r"""
Computes the GCD of two polynomials in `\mathbb{Z}[x]` using a modular
algorithm.
The algorithm computes the GCD of two univariate integer polynomials
`f` and `g` by computing the GCD in `\mathbb{Z}_p[x]` for suitable
primes `p` and then reconstructing the coefficients with the Chinese
Remainder Theorem. Trial division is only made for candidates which
are very likely the desired GCD.
Parameters
==========
f : PolyElement
univariate integer polynomial
g : PolyElement
univariate integer polynomial
Returns
=======
h : PolyElement
GCD of the polynomials `f` and `g`
cff : PolyElement
cofactor of `f`, i.e. `\frac{f}{h}`
cfg : PolyElement
cofactor of `g`, i.e. `\frac{g}{h}`
Examples
========
>>> from sympy.polys.modulargcd import modgcd_univariate
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> f = x**5 - 1
>>> g = x - 1
>>> h, cff, cfg = modgcd_univariate(f, g)
>>> h, cff, cfg
(x - 1, x**4 + x**3 + x**2 + x + 1, 1)
>>> cff * h == f
True
>>> cfg * h == g
True
>>> f = 6*x**2 - 6
>>> g = 2*x**2 + 4*x + 2
>>> h, cff, cfg = modgcd_univariate(f, g)
>>> h, cff, cfg
(2*x + 2, 3*x - 3, x + 1)
>>> cff * h == f
True
>>> cfg * h == g
True
References
==========
1. [Monagan00]_
"""
assert f.ring == g.ring and f.ring.domain.is_ZZ
result = _trivial_gcd(f, g)
if result is not None:
return result
ring = f.ring
cf, f = f.primitive()
cg, g = g.primitive()
ch = ring.domain.gcd(cf, cg)
bound = _degree_bound_univariate(f, g)
if bound == 0:
return ring(ch), f.mul_ground(cf // ch), g.mul_ground(cg // ch)
gamma = ring.domain.gcd(f.LC, g.LC)
m = 1
p = 1
while True:
p = nextprime(p)
while gamma % p == 0:
p = nextprime(p)
fp = f.trunc_ground(p)
gp = g.trunc_ground(p)
hp = _gf_gcd(fp, gp, p)
deghp = hp.degree()
if deghp > bound:
continue
elif deghp < bound:
m = 1
bound = deghp
continue
hp = hp.mul_ground(gamma).trunc_ground(p)
if m == 1:
m = p
hlastm = hp
continue
hm = _chinese_remainder_reconstruction_univariate(hp, hlastm, p, m)
m *= p
if not hm == hlastm:
hlastm = hm
continue
h = hm.quo_ground(hm.content())
fquo, frem = f.div(h)
gquo, grem = g.div(h)
if not frem and not grem:
if h.LC < 0:
ch = -ch
h = h.mul_ground(ch)
cff = fquo.mul_ground(cf // ch)
cfg = gquo.mul_ground(cg // ch)
return h, cff, cfg
def _primitive(f, p):
r"""
Compute the content and the primitive part of a polynomial in
`\mathbb{Z}_p[x_0, \ldots, x_{k-2}, y] \cong \mathbb{Z}_p[y][x_0, \ldots, x_{k-2}]`.
Parameters
==========
f : PolyElement
integer polynomial in `\mathbb{Z}_p[x0, \ldots, x{k-2}, y]`
p : Integer
modulus of `f`
Returns
=======
contf : PolyElement
integer polynomial in `\mathbb{Z}_p[y]`, content of `f`
ppf : PolyElement
primitive part of `f`, i.e. `\frac{f}{contf}`
Examples
========
>>> from sympy.polys.modulargcd import _primitive
>>> from sympy.polys import ring, ZZ
>>> R, x, y = ring("x, y", ZZ)
>>> p = 3
>>> f = x**2*y**2 + x**2*y - y**2 - y
>>> _primitive(f, p)
(y**2 + y, x**2 - 1)
>>> R, x, y, z = ring("x, y, z", ZZ)
>>> f = x*y*z - y**2*z**2
>>> _primitive(f, p)
(z, x*y - y**2*z)
"""
ring = f.ring
dom = ring.domain
k = ring.ngens
coeffs = {}
for monom, coeff in f.iterterms():
if monom[:-1] not in coeffs:
coeffs[monom[:-1]] = {}
coeffs[monom[:-1]][monom[-1]] = coeff
cont = []
for coeff in iter(coeffs.values()):
cont = gf_gcd(cont, gf_from_dict(coeff, p, dom), p, dom)
yring = ring.clone(symbols=ring.symbols[k-1])
contf = yring.from_dense(cont).trunc_ground(p)
return contf, f.quo(contf.set_ring(ring))
def _deg(f):
r"""
Compute the degree of a multivariate polynomial
`f \in K[x_0, \ldots, x_{k-2}, y] \cong K[y][x_0, \ldots, x_{k-2}]`.
Parameters
==========
f : PolyElement
polynomial in `K[x_0, \ldots, x_{k-2}, y]`
Returns
=======
degf : Integer tuple
degree of `f` in `x_0, \ldots, x_{k-2}`
Examples
========
>>> from sympy.polys.modulargcd import _deg
>>> from sympy.polys import ring, ZZ
>>> R, x, y = ring("x, y", ZZ)
>>> f = x**2*y**2 + x**2*y - 1
>>> _deg(f)
(2,)
>>> R, x, y, z = ring("x, y, z", ZZ)
>>> f = x**2*y**2 + x**2*y - 1
>>> _deg(f)
(2, 2)
>>> f = x*y*z - y**2*z**2
>>> _deg(f)
(1, 1)
"""
k = f.ring.ngens
degf = (0,) * (k-1)
for monom in f.itermonoms():
if monom[:-1] > degf:
degf = monom[:-1]
return degf
def _LC(f):
r"""
Compute the leading coefficient of a multivariate polynomial
`f \in K[x_0, \ldots, x_{k-2}, y] \cong K[y][x_0, \ldots, x_{k-2}]`.
Parameters
==========
f : PolyElement
polynomial in `K[x_0, \ldots, x_{k-2}, y]`
Returns
=======
lcf : PolyElement
polynomial in `K[y]`, leading coefficient of `f`
Examples
========
>>> from sympy.polys.modulargcd import _LC
>>> from sympy.polys import ring, ZZ
>>> R, x, y = ring("x, y", ZZ)
>>> f = x**2*y**2 + x**2*y - 1
>>> _LC(f)
y**2 + y
>>> R, x, y, z = ring("x, y, z", ZZ)
>>> f = x**2*y**2 + x**2*y - 1
>>> _LC(f)
1
>>> f = x*y*z - y**2*z**2
>>> _LC(f)
z
"""
ring = f.ring
k = ring.ngens
yring = ring.clone(symbols=ring.symbols[k-1])
y = yring.gens[0]
degf = _deg(f)
lcf = yring.zero
for monom, coeff in f.iterterms():
if monom[:-1] == degf:
lcf += coeff*y**monom[-1]
return lcf
def _swap(f, i):
"""
Make the variable `x_i` the leading one in a multivariate polynomial `f`.
"""
ring = f.ring
fswap = ring.zero
for monom, coeff in f.iterterms():
monomswap = (monom[i],) + monom[:i] + monom[i+1:]
fswap[monomswap] = coeff
return fswap
def _degree_bound_bivariate(f, g):
r"""
Compute upper degree bounds for the GCD of two bivariate
integer polynomials `f` and `g`.
The GCD is viewed as a polynomial in `\mathbb{Z}[y][x]` and the
function returns an upper bound for its degree and one for the degree
of its content. This is done by choosing a suitable prime `p` and
computing the GCD of the contents of `f \; \mathrm{mod} \, p` and
`g \; \mathrm{mod} \, p`. The choice of `p` guarantees that the degree
of the content in `\mathbb{Z}_p[y]` is greater than or equal to the
degree in `\mathbb{Z}[y]`. To obtain the degree bound in the variable
`x`, the polynomials are evaluated at `y = a` for a suitable
`a \in \mathbb{Z}_p` and then their GCD in `\mathbb{Z}_p[x]` is
computed. If no such `a` exists, i.e. the degree in `\mathbb{Z}_p[x]`
is always smaller than the one in `\mathbb{Z}[y][x]`, then the bound is
set to the minimum of the degrees of `f` and `g` in `x`.
Parameters
==========
f : PolyElement
bivariate integer polynomial
g : PolyElement
bivariate integer polynomial
Returns
=======
xbound : Integer
upper bound for the degree of the GCD of the polynomials `f` and
`g` in the variable `x`
ycontbound : Integer
upper bound for the degree of the content of the GCD of the
polynomials `f` and `g` in the variable `y`
References
==========
1. [Monagan00]_
"""
ring = f.ring
gamma1 = ring.domain.gcd(f.LC, g.LC)
gamma2 = ring.domain.gcd(_swap(f, 1).LC, _swap(g, 1).LC)
badprimes = gamma1 * gamma2
p = 1
p = nextprime(p)
while badprimes % p == 0:
p = nextprime(p)
fp = f.trunc_ground(p)
gp = g.trunc_ground(p)
contfp, fp = _primitive(fp, p)
contgp, gp = _primitive(gp, p)
conthp = _gf_gcd(contfp, contgp, p) # polynomial in Z_p[y]
ycontbound = conthp.degree()
# polynomial in Z_p[y]
delta = _gf_gcd(_LC(fp), _LC(gp), p)
for a in range(p):
if not delta.evaluate(0, a) % p:
continue
fpa = fp.evaluate(1, a).trunc_ground(p)
gpa = gp.evaluate(1, a).trunc_ground(p)
hpa = _gf_gcd(fpa, gpa, p)
xbound = hpa.degree()
return xbound, ycontbound
return min(fp.degree(), gp.degree()), ycontbound
def _chinese_remainder_reconstruction_multivariate(hp, hq, p, q):
r"""
Construct a polynomial `h_{pq}` in
`\mathbb{Z}_{p q}[x_0, \ldots, x_{k-1}]` such that
.. math ::
h_{pq} = h_p \; \mathrm{mod} \, p
h_{pq} = h_q \; \mathrm{mod} \, q
for relatively prime integers `p` and `q` and polynomials
`h_p` and `h_q` in `\mathbb{Z}_p[x_0, \ldots, x_{k-1}]` and
`\mathbb{Z}_q[x_0, \ldots, x_{k-1}]` respectively.
The coefficients of the polynomial `h_{pq}` are computed with the
Chinese Remainder Theorem. The symmetric representation in
`\mathbb{Z}_p[x_0, \ldots, x_{k-1}]`,
`\mathbb{Z}_q[x_0, \ldots, x_{k-1}]` and
`\mathbb{Z}_{p q}[x_0, \ldots, x_{k-1}]` is used.
Parameters
==========
hp : PolyElement
multivariate integer polynomial with coefficients in `\mathbb{Z}_p`
hq : PolyElement
multivariate integer polynomial with coefficients in `\mathbb{Z}_q`
p : Integer
modulus of `h_p`, relatively prime to `q`
q : Integer
modulus of `h_q`, relatively prime to `p`
Examples
========
>>> from sympy.polys.modulargcd import _chinese_remainder_reconstruction_multivariate
>>> from sympy.polys import ring, ZZ
>>> R, x, y = ring("x, y", ZZ)
>>> p = 3
>>> q = 5
>>> hp = x**3*y - x**2 - 1
>>> hq = -x**3*y - 2*x*y**2 + 2
>>> hpq = _chinese_remainder_reconstruction_multivariate(hp, hq, p, q)
>>> hpq
4*x**3*y + 5*x**2 + 3*x*y**2 + 2
>>> hpq.trunc_ground(p) == hp
True
>>> hpq.trunc_ground(q) == hq
True
>>> R, x, y, z = ring("x, y, z", ZZ)
>>> p = 6
>>> q = 5
>>> hp = 3*x**4 - y**3*z + z
>>> hq = -2*x**4 + z
>>> hpq = _chinese_remainder_reconstruction_multivariate(hp, hq, p, q)
>>> hpq
3*x**4 + 5*y**3*z + z
>>> hpq.trunc_ground(p) == hp
True
>>> hpq.trunc_ground(q) == hq
True
"""
hpmonoms = set(hp.monoms())
hqmonoms = set(hq.monoms())
monoms = hpmonoms.intersection(hqmonoms)
hpmonoms.difference_update(monoms)
hqmonoms.difference_update(monoms)
zero = hp.ring.domain.zero
hpq = hp.ring.zero
if isinstance(hp.ring.domain, PolynomialRing):
crt_ = _chinese_remainder_reconstruction_multivariate
else:
def crt_(cp, cq, p, q):
return crt([p, q], [cp, cq], symmetric=True)[0]
for monom in monoms:
hpq[monom] = crt_(hp[monom], hq[monom], p, q)
for monom in hpmonoms:
hpq[monom] = crt_(hp[monom], zero, p, q)
for monom in hqmonoms:
hpq[monom] = crt_(zero, hq[monom], p, q)
return hpq
def _interpolate_multivariate(evalpoints, hpeval, ring, i, p, ground=False):
r"""
Reconstruct a polynomial `h_p` in `\mathbb{Z}_p[x_0, \ldots, x_{k-1}]`
from a list of evaluation points in `\mathbb{Z}_p` and a list of
polynomials in
`\mathbb{Z}_p[x_0, \ldots, x_{i-1}, x_{i+1}, \ldots, x_{k-1}]`, which
are the images of `h_p` evaluated in the variable `x_i`.
It is also possible to reconstruct a parameter of the ground domain,
i.e. if `h_p` is a polynomial over `\mathbb{Z}_p[x_0, \ldots, x_{k-1}]`.
In this case, one has to set ``ground=True``.
Parameters
==========
evalpoints : list of Integer objects
list of evaluation points in `\mathbb{Z}_p`
hpeval : list of PolyElement objects
list of polynomials in (resp. over)
`\mathbb{Z}_p[x_0, \ldots, x_{i-1}, x_{i+1}, \ldots, x_{k-1}]`,
images of `h_p` evaluated in the variable `x_i`
ring : PolyRing
`h_p` will be an element of this ring
i : Integer
index of the variable which has to be reconstructed
p : Integer
prime number, modulus of `h_p`
ground : Boolean
indicates whether `x_i` is in the ground domain, default is
``False``
Returns
=======
hp : PolyElement
interpolated polynomial in (resp. over)
`\mathbb{Z}_p[x_0, \ldots, x_{k-1}]`
"""
hp = ring.zero
if ground:
domain = ring.domain.domain
y = ring.domain.gens[i]
else:
domain = ring.domain
y = ring.gens[i]
for a, hpa in zip(evalpoints, hpeval):
numer = ring.one
denom = domain.one
for b in evalpoints:
if b == a:
continue
numer *= y - b
denom *= a - b
denom = domain.invert(denom, p)
coeff = numer.mul_ground(denom)
hp += hpa.set_ring(ring) * coeff
return hp.trunc_ground(p)
def modgcd_bivariate(f, g):
r"""
Computes the GCD of two polynomials in `\mathbb{Z}[x, y]` using a
modular algorithm.
The algorithm computes the GCD of two bivariate integer polynomials
`f` and `g` by calculating the GCD in `\mathbb{Z}_p[x, y]` for
suitable primes `p` and then reconstructing the coefficients with the
Chinese Remainder Theorem. To compute the bivariate GCD over
`\mathbb{Z}_p`, the polynomials `f \; \mathrm{mod} \, p` and
`g \; \mathrm{mod} \, p` are evaluated at `y = a` for certain
`a \in \mathbb{Z}_p` and then their univariate GCD in `\mathbb{Z}_p[x]`
is computed. Interpolating those yields the bivariate GCD in
`\mathbb{Z}_p[x, y]`. To verify the result in `\mathbb{Z}[x, y]`, trial
division is done, but only for candidates which are very likely the
desired GCD.
Parameters
==========
f : PolyElement
bivariate integer polynomial
g : PolyElement
bivariate integer polynomial
Returns
=======
h : PolyElement
GCD of the polynomials `f` and `g`
cff : PolyElement
cofactor of `f`, i.e. `\frac{f}{h}`
cfg : PolyElement
cofactor of `g`, i.e. `\frac{g}{h}`
Examples
========
>>> from sympy.polys.modulargcd import modgcd_bivariate
>>> from sympy.polys import ring, ZZ
>>> R, x, y = ring("x, y", ZZ)
>>> f = x**2 - y**2
>>> g = x**2 + 2*x*y + y**2
>>> h, cff, cfg = modgcd_bivariate(f, g)
>>> h, cff, cfg
(x + y, x - y, x + y)
>>> cff * h == f
True
>>> cfg * h == g
True
>>> f = x**2*y - x**2 - 4*y + 4
>>> g = x + 2
>>> h, cff, cfg = modgcd_bivariate(f, g)
>>> h, cff, cfg
(x + 2, x*y - x - 2*y + 2, 1)
>>> cff * h == f
True
>>> cfg * h == g
True
References
==========
1. [Monagan00]_
"""
assert f.ring == g.ring and f.ring.domain.is_ZZ
result = _trivial_gcd(f, g)
if result is not None:
return result
ring = f.ring
cf, f = f.primitive()
cg, g = g.primitive()
ch = ring.domain.gcd(cf, cg)
xbound, ycontbound = _degree_bound_bivariate(f, g)
if xbound == ycontbound == 0:
return ring(ch), f.mul_ground(cf // ch), g.mul_ground(cg // ch)
fswap = _swap(f, 1)
gswap = _swap(g, 1)
degyf = fswap.degree()
degyg = gswap.degree()
ybound, xcontbound = _degree_bound_bivariate(fswap, gswap)
if ybound == xcontbound == 0:
return ring(ch), f.mul_ground(cf // ch), g.mul_ground(cg // ch)
# TODO: to improve performance, choose the main variable here
gamma1 = ring.domain.gcd(f.LC, g.LC)
gamma2 = ring.domain.gcd(fswap.LC, gswap.LC)
badprimes = gamma1 * gamma2
m = 1
p = 1
while True:
p = nextprime(p)
while badprimes % p == 0:
p = nextprime(p)
fp = f.trunc_ground(p)
gp = g.trunc_ground(p)
contfp, fp = _primitive(fp, p)
contgp, gp = _primitive(gp, p)
conthp = _gf_gcd(contfp, contgp, p) # monic polynomial in Z_p[y]
degconthp = conthp.degree()
if degconthp > ycontbound:
continue
elif degconthp < ycontbound:
m = 1
ycontbound = degconthp
continue
# polynomial in Z_p[y]
delta = _gf_gcd(_LC(fp), _LC(gp), p)
degcontfp = contfp.degree()
degcontgp = contgp.degree()
degdelta = delta.degree()
N = min(degyf - degcontfp, degyg - degcontgp,
ybound - ycontbound + degdelta) + 1
if p < N:
continue
n = 0
evalpoints = []
hpeval = []
unlucky = False
for a in range(p):
deltaa = delta.evaluate(0, a)
if not deltaa % p:
continue
fpa = fp.evaluate(1, a).trunc_ground(p)
gpa = gp.evaluate(1, a).trunc_ground(p)
hpa = _gf_gcd(fpa, gpa, p) # monic polynomial in Z_p[x]
deghpa = hpa.degree()
if deghpa > xbound:
continue
elif deghpa < xbound:
m = 1
xbound = deghpa
unlucky = True
break
hpa = hpa.mul_ground(deltaa).trunc_ground(p)
evalpoints.append(a)
hpeval.append(hpa)
n += 1
if n == N:
break
if unlucky:
continue
if n < N:
continue
hp = _interpolate_multivariate(evalpoints, hpeval, ring, 1, p)
hp = _primitive(hp, p)[1]
hp = hp * conthp.set_ring(ring)
degyhp = hp.degree(1)
if degyhp > ybound:
continue
if degyhp < ybound:
m = 1
ybound = degyhp
continue
hp = hp.mul_ground(gamma1).trunc_ground(p)
if m == 1:
m = p
hlastm = hp
continue
hm = _chinese_remainder_reconstruction_multivariate(hp, hlastm, p, m)
m *= p
if not hm == hlastm:
hlastm = hm
continue
h = hm.quo_ground(hm.content())
fquo, frem = f.div(h)
gquo, grem = g.div(h)
if not frem and not grem:
if h.LC < 0:
ch = -ch
h = h.mul_ground(ch)
cff = fquo.mul_ground(cf // ch)
cfg = gquo.mul_ground(cg // ch)
return h, cff, cfg
def _modgcd_multivariate_p(f, g, p, degbound, contbound):
r"""
Compute the GCD of two polynomials in
`\mathbb{Z}_p[x_0, \ldots, x_{k-1}]`.
The algorithm reduces the problem step by step by evaluating the
polynomials `f` and `g` at `x_{k-1} = a` for suitable
`a \in \mathbb{Z}_p` and then calls itself recursively to compute the GCD
in `\mathbb{Z}_p[x_0, \ldots, x_{k-2}]`. If these recursive calls are
successful for enough evaluation points, the GCD in `k` variables is
interpolated, otherwise the algorithm returns ``None``. Every time a GCD
or a content is computed, their degrees are compared with the bounds. If
a degree greater then the bound is encountered, then the current call
returns ``None`` and a new evaluation point has to be chosen. If at some
point the degree is smaller, the correspondent bound is updated and the
algorithm fails.
Parameters
==========
f : PolyElement
multivariate integer polynomial with coefficients in `\mathbb{Z}_p`
g : PolyElement
multivariate integer polynomial with coefficients in `\mathbb{Z}_p`
p : Integer
prime number, modulus of `f` and `g`
degbound : list of Integer objects
``degbound[i]`` is an upper bound for the degree of the GCD of `f`
and `g` in the variable `x_i`
contbound : list of Integer objects
``contbound[i]`` is an upper bound for the degree of the content of
the GCD in `\mathbb{Z}_p[x_i][x_0, \ldots, x_{i-1}]`,
``contbound[0]`` is not used can therefore be chosen
arbitrarily.
Returns
=======
h : PolyElement
GCD of the polynomials `f` and `g` or ``None``
References
==========
1. [Monagan00]_
2. [Brown71]_
"""
ring = f.ring
k = ring.ngens
if k == 1:
h = _gf_gcd(f, g, p).trunc_ground(p)
degh = h.degree()
if degh > degbound[0]:
return None
if degh < degbound[0]:
degbound[0] = degh
raise ModularGCDFailed
return h
degyf = f.degree(k-1)
degyg = g.degree(k-1)
contf, f = _primitive(f, p)
contg, g = _primitive(g, p)
conth = _gf_gcd(contf, contg, p) # polynomial in Z_p[y]
degcontf = contf.degree()
degcontg = contg.degree()
degconth = conth.degree()
if degconth > contbound[k-1]:
return None
if degconth < contbound[k-1]:
contbound[k-1] = degconth
raise ModularGCDFailed
lcf = _LC(f)
lcg = _LC(g)
delta = _gf_gcd(lcf, lcg, p) # polynomial in Z_p[y]
evaltest = delta
for i in range(k-1):
evaltest *= _gf_gcd(_LC(_swap(f, i)), _LC(_swap(g, i)), p)
degdelta = delta.degree()
N = min(degyf - degcontf, degyg - degcontg,
degbound[k-1] - contbound[k-1] + degdelta) + 1
if p < N:
return None
n = 0
d = 0
evalpoints = []
heval = []
points = list(range(p))
while points:
a = random.sample(points, 1)[0]
points.remove(a)
if not evaltest.evaluate(0, a) % p:
continue
deltaa = delta.evaluate(0, a) % p
fa = f.evaluate(k-1, a).trunc_ground(p)
ga = g.evaluate(k-1, a).trunc_ground(p)
# polynomials in Z_p[x_0, ..., x_{k-2}]
ha = _modgcd_multivariate_p(fa, ga, p, degbound, contbound)
if ha is None:
d += 1
if d > n:
return None
continue
if ha.is_ground:
h = conth.set_ring(ring).trunc_ground(p)
return h
ha = ha.mul_ground(deltaa).trunc_ground(p)
evalpoints.append(a)
heval.append(ha)
n += 1
if n == N:
h = _interpolate_multivariate(evalpoints, heval, ring, k-1, p)
h = _primitive(h, p)[1] * conth.set_ring(ring)
degyh = h.degree(k-1)
if degyh > degbound[k-1]:
return None
if degyh < degbound[k-1]:
degbound[k-1] = degyh
raise ModularGCDFailed
return h
return None
def modgcd_multivariate(f, g):
r"""
Compute the GCD of two polynomials in `\mathbb{Z}[x_0, \ldots, x_{k-1}]`
using a modular algorithm.
The algorithm computes the GCD of two multivariate integer polynomials
`f` and `g` by calculating the GCD in
`\mathbb{Z}_p[x_0, \ldots, x_{k-1}]` for suitable primes `p` and then
reconstructing the coefficients with the Chinese Remainder Theorem. To
compute the multivariate GCD over `\mathbb{Z}_p` the recursive
subroutine :func:`_modgcd_multivariate_p` is used. To verify the result in
`\mathbb{Z}[x_0, \ldots, x_{k-1}]`, trial division is done, but only for
candidates which are very likely the desired GCD.
Parameters
==========
f : PolyElement
multivariate integer polynomial
g : PolyElement
multivariate integer polynomial
Returns
=======
h : PolyElement
GCD of the polynomials `f` and `g`
cff : PolyElement
cofactor of `f`, i.e. `\frac{f}{h}`
cfg : PolyElement
cofactor of `g`, i.e. `\frac{g}{h}`
Examples
========
>>> from sympy.polys.modulargcd import modgcd_multivariate
>>> from sympy.polys import ring, ZZ
>>> R, x, y = ring("x, y", ZZ)
>>> f = x**2 - y**2
>>> g = x**2 + 2*x*y + y**2
>>> h, cff, cfg = modgcd_multivariate(f, g)
>>> h, cff, cfg
(x + y, x - y, x + y)
>>> cff * h == f
True
>>> cfg * h == g
True
>>> R, x, y, z = ring("x, y, z", ZZ)
>>> f = x*z**2 - y*z**2
>>> g = x**2*z + z
>>> h, cff, cfg = modgcd_multivariate(f, g)
>>> h, cff, cfg
(z, x*z - y*z, x**2 + 1)
>>> cff * h == f
True
>>> cfg * h == g
True
References
==========
1. [Monagan00]_
2. [Brown71]_
See also
========
_modgcd_multivariate_p
"""
assert f.ring == g.ring and f.ring.domain.is_ZZ
result = _trivial_gcd(f, g)
if result is not None:
return result
ring = f.ring
k = ring.ngens
# divide out integer content
cf, f = f.primitive()
cg, g = g.primitive()
ch = ring.domain.gcd(cf, cg)
gamma = ring.domain.gcd(f.LC, g.LC)
badprimes = ring.domain.one
for i in range(k):
badprimes *= ring.domain.gcd(_swap(f, i).LC, _swap(g, i).LC)
degbound = [min(fdeg, gdeg) for fdeg, gdeg in zip(f.degrees(), g.degrees())]
contbound = list(degbound)
m = 1
p = 1
while True:
p = nextprime(p)
while badprimes % p == 0:
p = nextprime(p)
fp = f.trunc_ground(p)
gp = g.trunc_ground(p)
try:
# monic GCD of fp, gp in Z_p[x_0, ..., x_{k-2}, y]
hp = _modgcd_multivariate_p(fp, gp, p, degbound, contbound)
except ModularGCDFailed:
m = 1
continue
if hp is None:
continue
hp = hp.mul_ground(gamma).trunc_ground(p)
if m == 1:
m = p
hlastm = hp
continue
hm = _chinese_remainder_reconstruction_multivariate(hp, hlastm, p, m)
m *= p
if not hm == hlastm:
hlastm = hm
continue
h = hm.primitive()[1]
fquo, frem = f.div(h)
gquo, grem = g.div(h)
if not frem and not grem:
if h.LC < 0:
ch = -ch
h = h.mul_ground(ch)
cff = fquo.mul_ground(cf // ch)
cfg = gquo.mul_ground(cg // ch)
return h, cff, cfg
def _gf_div(f, g, p):
r"""
Compute `\frac f g` modulo `p` for two univariate polynomials over
`\mathbb Z_p`.
"""
ring = f.ring
densequo, denserem = gf_div(f.to_dense(), g.to_dense(), p, ring.domain)
return ring.from_dense(densequo), ring.from_dense(denserem)
def _rational_function_reconstruction(c, p, m):
r"""
Reconstruct a rational function `\frac a b` in `\mathbb Z_p(t)` from
.. math::
c = \frac a b \; \mathrm{mod} \, m,
where `c` and `m` are polynomials in `\mathbb Z_p[t]` and `m` has
positive degree.
The algorithm is based on the Euclidean Algorithm. In general, `m` is
not irreducible, so it is possible that `b` is not invertible modulo
`m`. In that case ``None`` is returned.
Parameters
==========
c : PolyElement
univariate polynomial in `\mathbb Z[t]`
p : Integer
prime number
m : PolyElement
modulus, not necessarily irreducible
Returns
=======
frac : FracElement
either `\frac a b` in `\mathbb Z(t)` or ``None``
References
==========
1. [Hoeij04]_
"""
ring = c.ring
domain = ring.domain
M = m.degree()
N = M // 2
D = M - N - 1
r0, s0 = m, ring.zero
r1, s1 = c, ring.one
while r1.degree() > N:
quo = _gf_div(r0, r1, p)[0]
r0, r1 = r1, (r0 - quo*r1).trunc_ground(p)
s0, s1 = s1, (s0 - quo*s1).trunc_ground(p)
a, b = r1, s1
if b.degree() > D or _gf_gcd(b, m, p) != 1:
return None
lc = b.LC
if lc != 1:
lcinv = domain.invert(lc, p)
a = a.mul_ground(lcinv).trunc_ground(p)
b = b.mul_ground(lcinv).trunc_ground(p)
field = ring.to_field()
return field(a) / field(b)
def _rational_reconstruction_func_coeffs(hm, p, m, ring, k):
r"""
Reconstruct every coefficient `c_h` of a polynomial `h` in
`\mathbb Z_p(t_k)[t_1, \ldots, t_{k-1}][x, z]` from the corresponding
coefficient `c_{h_m}` of a polynomial `h_m` in
`\mathbb Z_p[t_1, \ldots, t_k][x, z] \cong \mathbb Z_p[t_k][t_1, \ldots, t_{k-1}][x, z]`
such that
.. math::
c_{h_m} = c_h \; \mathrm{mod} \, m,
where `m \in \mathbb Z_p[t]`.
The reconstruction is based on the Euclidean Algorithm. In general, `m`
is not irreducible, so it is possible that this fails for some
coefficient. In that case ``None`` is returned.
Parameters
==========
hm : PolyElement
polynomial in `\mathbb Z[t_1, \ldots, t_k][x, z]`
p : Integer
prime number, modulus of `\mathbb Z_p`
m : PolyElement
modulus, polynomial in `\mathbb Z[t]`, not necessarily irreducible
ring : PolyRing
`\mathbb Z(t_k)[t_1, \ldots, t_{k-1}][x, z]`, `h` will be an
element of this ring
k : Integer
index of the parameter `t_k` which will be reconstructed
Returns
=======
h : PolyElement
reconstructed polynomial in
`\mathbb Z(t_k)[t_1, \ldots, t_{k-1}][x, z]` or ``None``
See also
========
_rational_function_reconstruction
"""
h = ring.zero
for monom, coeff in hm.iterterms():
if k == 0:
coeffh = _rational_function_reconstruction(coeff, p, m)
if not coeffh:
return None
else:
coeffh = ring.domain.zero
for mon, c in coeff.drop_to_ground(k).iterterms():
ch = _rational_function_reconstruction(c, p, m)
if not ch:
return None
coeffh[mon] = ch
h[monom] = coeffh
return h
def _gf_gcdex(f, g, p):
r"""
Extended Euclidean Algorithm for two univariate polynomials over
`\mathbb Z_p`.
Returns polynomials `s, t` and `h`, such that `h` is the GCD of `f` and
`g` and `sf + tg = h \; \mathrm{mod} \, p`.
"""
ring = f.ring
s, t, h = gf_gcdex(f.to_dense(), g.to_dense(), p, ring.domain)
return ring.from_dense(s), ring.from_dense(t), ring.from_dense(h)
def _trunc(f, minpoly, p):
r"""
Compute the reduced representation of a polynomial `f` in
`\mathbb Z_p[z] / (\check m_{\alpha}(z))[x]`
Parameters
==========
f : PolyElement
polynomial in `\mathbb Z[x, z]`
minpoly : PolyElement
polynomial `\check m_{\alpha} \in \mathbb Z[z]`, not necessarily
irreducible
p : Integer
prime number, modulus of `\mathbb Z_p`
Returns
=======
ftrunc : PolyElement
polynomial in `\mathbb Z[x, z]`, reduced modulo
`\check m_{\alpha}(z)` and `p`
"""
ring = f.ring
minpoly = minpoly.set_ring(ring)
p_ = ring.ground_new(p)
return f.trunc_ground(p).rem([minpoly, p_]).trunc_ground(p)
def _euclidean_algorithm(f, g, minpoly, p):
r"""
Compute the monic GCD of two univariate polynomials in
`\mathbb{Z}_p[z]/(\check m_{\alpha}(z))[x]` with the Euclidean
Algorithm.
In general, `\check m_{\alpha}(z)` is not irreducible, so it is possible
that some leading coefficient is not invertible modulo
`\check m_{\alpha}(z)`. In that case ``None`` is returned.
Parameters
==========
f, g : PolyElement
polynomials in `\mathbb Z[x, z]`
minpoly : PolyElement
polynomial in `\mathbb Z[z]`, not necessarily irreducible
p : Integer
prime number, modulus of `\mathbb Z_p`
Returns
=======
h : PolyElement
GCD of `f` and `g` in `\mathbb Z[z, x]` or ``None``, coefficients
are in `\left[ -\frac{p-1} 2, \frac{p-1} 2 \right]`
"""
ring = f.ring
f = _trunc(f, minpoly, p)
g = _trunc(g, minpoly, p)
while g:
rem = f
deg = g.degree(0) # degree in x
lcinv, _, gcd = _gf_gcdex(ring.dmp_LC(g), minpoly, p)
if not gcd == 1:
return None
while True:
degrem = rem.degree(0) # degree in x
if degrem < deg:
break
quo = (lcinv * ring.dmp_LC(rem)).set_ring(ring)
rem = _trunc(rem - g.mul_monom((degrem - deg, 0))*quo, minpoly, p)
f = g
g = rem
lcfinv = _gf_gcdex(ring.dmp_LC(f), minpoly, p)[0].set_ring(ring)
return _trunc(f * lcfinv, minpoly, p)
def _trial_division(f, h, minpoly, p=None):
r"""
Check if `h` divides `f` in
`\mathbb K[t_1, \ldots, t_k][z]/(m_{\alpha}(z))`, where `\mathbb K` is
either `\mathbb Q` or `\mathbb Z_p`.
This algorithm is based on pseudo division and does not use any
fractions. By default `\mathbb K` is `\mathbb Q`, if a prime number `p`
is given, `\mathbb Z_p` is chosen instead.
Parameters
==========
f, h : PolyElement
polynomials in `\mathbb Z[t_1, \ldots, t_k][x, z]`
minpoly : PolyElement
polynomial `m_{\alpha}(z)` in `\mathbb Z[t_1, \ldots, t_k][z]`
p : Integer or None
if `p` is given, `\mathbb K` is set to `\mathbb Z_p` instead of
`\mathbb Q`, default is ``None``
Returns
=======
rem : PolyElement
remainder of `\frac f h`
References
==========
.. [1] [Hoeij02]_
"""
ring = f.ring
zxring = ring.clone(symbols=(ring.symbols[1], ring.symbols[0]))
minpoly = minpoly.set_ring(ring)
rem = f
degrem = rem.degree()
degh = h.degree()
degm = minpoly.degree(1)
lch = _LC(h).set_ring(ring)
lcm = minpoly.LC
while rem and degrem >= degh:
# polynomial in Z[t_1, ..., t_k][z]
lcrem = _LC(rem).set_ring(ring)
rem = rem*lch - h.mul_monom((degrem - degh, 0))*lcrem
if p:
rem = rem.trunc_ground(p)
degrem = rem.degree(1)
while rem and degrem >= degm:
# polynomial in Z[t_1, ..., t_k][x]
lcrem = _LC(rem.set_ring(zxring)).set_ring(ring)
rem = rem.mul_ground(lcm) - minpoly.mul_monom((0, degrem - degm))*lcrem
if p:
rem = rem.trunc_ground(p)
degrem = rem.degree(1)
degrem = rem.degree()
return rem
def _evaluate_ground(f, i, a):
r"""
Evaluate a polynomial `f` at `a` in the `i`-th variable of the ground
domain.
"""
ring = f.ring.clone(domain=f.ring.domain.ring.drop(i))
fa = ring.zero
for monom, coeff in f.iterterms():
fa[monom] = coeff.evaluate(i, a)
return fa
def _func_field_modgcd_p(f, g, minpoly, p):
r"""
Compute the GCD of two polynomials `f` and `g` in
`\mathbb Z_p(t_1, \ldots, t_k)[z]/(\check m_\alpha(z))[x]`.
The algorithm reduces the problem step by step by evaluating the
polynomials `f` and `g` at `t_k = a` for suitable `a \in \mathbb Z_p`
and then calls itself recursively to compute the GCD in
`\mathbb Z_p(t_1, \ldots, t_{k-1})[z]/(\check m_\alpha(z))[x]`. If these
recursive calls are successful, the GCD over `k` variables is
interpolated, otherwise the algorithm returns ``None``. After
interpolation, Rational Function Reconstruction is used to obtain the
correct coefficients. If this fails, a new evaluation point has to be
chosen, otherwise the desired polynomial is obtained by clearing
denominators. The result is verified with a fraction free trial
division.
Parameters
==========
f, g : PolyElement
polynomials in `\mathbb Z[t_1, \ldots, t_k][x, z]`
minpoly : PolyElement
polynomial in `\mathbb Z[t_1, \ldots, t_k][z]`, not necessarily
irreducible
p : Integer
prime number, modulus of `\mathbb Z_p`
Returns
=======
h : PolyElement
primitive associate in `\mathbb Z[t_1, \ldots, t_k][x, z]` of the
GCD of the polynomials `f` and `g` or ``None``, coefficients are
in `\left[ -\frac{p-1} 2, \frac{p-1} 2 \right]`
References
==========
1. [Hoeij04]_
"""
ring = f.ring
domain = ring.domain # Z[t_1, ..., t_k]
if isinstance(domain, PolynomialRing):
k = domain.ngens
else:
return _euclidean_algorithm(f, g, minpoly, p)
if k == 1:
qdomain = domain.ring.to_field()
else:
qdomain = domain.ring.drop_to_ground(k - 1)
qdomain = qdomain.clone(domain=qdomain.domain.ring.to_field())
qring = ring.clone(domain=qdomain) # = Z(t_k)[t_1, ..., t_{k-1}][x, z]
n = 1
d = 1
# polynomial in Z_p[t_1, ..., t_k][z]
gamma = ring.dmp_LC(f) * ring.dmp_LC(g)
# polynomial in Z_p[t_1, ..., t_k]
delta = minpoly.LC
evalpoints = []
heval = []
LMlist = []
points = list(range(p))
while points:
a = random.sample(points, 1)[0]
points.remove(a)
if k == 1:
test = delta.evaluate(k-1, a) % p == 0
else:
test = delta.evaluate(k-1, a).trunc_ground(p) == 0
if test:
continue
gammaa = _evaluate_ground(gamma, k-1, a)
minpolya = _evaluate_ground(minpoly, k-1, a)
if gammaa.rem([minpolya, gammaa.ring(p)]) == 0:
continue
fa = _evaluate_ground(f, k-1, a)
ga = _evaluate_ground(g, k-1, a)
# polynomial in Z_p[x, t_1, ..., t_{k-1}, z]/(minpoly)
ha = _func_field_modgcd_p(fa, ga, minpolya, p)
if ha is None:
d += 1
if d > n:
return None
continue
if ha == 1:
return ha
LM = [ha.degree()] + [0]*(k-1)
if k > 1:
for monom, coeff in ha.iterterms():
if monom[0] == LM[0] and coeff.LM > tuple(LM[1:]):
LM[1:] = coeff.LM
evalpoints_a = [a]
heval_a = [ha]
if k == 1:
m = qring.domain.get_ring().one
else:
m = qring.domain.domain.get_ring().one
t = m.ring.gens[0]
for b, hb, LMhb in zip(evalpoints, heval, LMlist):
if LMhb == LM:
evalpoints_a.append(b)
heval_a.append(hb)
m *= (t - b)
m = m.trunc_ground(p)
evalpoints.append(a)
heval.append(ha)
LMlist.append(LM)
n += 1
# polynomial in Z_p[t_1, ..., t_k][x, z]
h = _interpolate_multivariate(evalpoints_a, heval_a, ring, k-1, p, ground=True)
# polynomial in Z_p(t_k)[t_1, ..., t_{k-1}][x, z]
h = _rational_reconstruction_func_coeffs(h, p, m, qring, k-1)
if h is None:
continue
if k == 1:
dom = qring.domain.field
den = dom.ring.one
for coeff in h.itercoeffs():
den = dom.ring.from_dense(gf_lcm(den.to_dense(), coeff.denom.to_dense(),
p, dom.domain))
else:
dom = qring.domain.domain.field
den = dom.ring.one
for coeff in h.itercoeffs():
for c in coeff.itercoeffs():
den = dom.ring.from_dense(gf_lcm(den.to_dense(), c.denom.to_dense(),
p, dom.domain))
den = qring.domain_new(den.trunc_ground(p))
h = ring(h.mul_ground(den).as_expr()).trunc_ground(p)
if not _trial_division(f, h, minpoly, p) and not _trial_division(g, h, minpoly, p):
return h
return None
def _integer_rational_reconstruction(c, m, domain):
r"""
Reconstruct a rational number `\frac a b` from
.. math::
c = \frac a b \; \mathrm{mod} \, m,
where `c` and `m` are integers.
The algorithm is based on the Euclidean Algorithm. In general, `m` is
not a prime number, so it is possible that `b` is not invertible modulo
`m`. In that case ``None`` is returned.
Parameters
==========
c : Integer
`c = \frac a b \; \mathrm{mod} \, m`
m : Integer
modulus, not necessarily prime
domain : IntegerRing
`a, b, c` are elements of ``domain``
Returns
=======
frac : Rational
either `\frac a b` in `\mathbb Q` or ``None``
References
==========
1. [Wang81]_
"""
if c < 0:
c += m
r0, s0 = m, domain.zero
r1, s1 = c, domain.one
bound = sqrt(m / 2) # still correct if replaced by ZZ.sqrt(m // 2) ?
while int(r1) >= bound:
quo = r0 // r1
r0, r1 = r1, r0 - quo*r1
s0, s1 = s1, s0 - quo*s1
if abs(int(s1)) >= bound:
return None
if s1 < 0:
a, b = -r1, -s1
elif s1 > 0:
a, b = r1, s1
else:
return None
field = domain.get_field()
return field(a) / field(b)
def _rational_reconstruction_int_coeffs(hm, m, ring):
r"""
Reconstruct every rational coefficient `c_h` of a polynomial `h` in
`\mathbb Q[t_1, \ldots, t_k][x, z]` from the corresponding integer
coefficient `c_{h_m}` of a polynomial `h_m` in
`\mathbb Z[t_1, \ldots, t_k][x, z]` such that
.. math::
c_{h_m} = c_h \; \mathrm{mod} \, m,
where `m \in \mathbb Z`.
The reconstruction is based on the Euclidean Algorithm. In general,
`m` is not a prime number, so it is possible that this fails for some
coefficient. In that case ``None`` is returned.
Parameters
==========
hm : PolyElement
polynomial in `\mathbb Z[t_1, \ldots, t_k][x, z]`
m : Integer
modulus, not necessarily prime
ring : PolyRing
`\mathbb Q[t_1, \ldots, t_k][x, z]`, `h` will be an element of this
ring
Returns
=======
h : PolyElement
reconstructed polynomial in `\mathbb Q[t_1, \ldots, t_k][x, z]` or
``None``
See also
========
_integer_rational_reconstruction
"""
h = ring.zero
if isinstance(ring.domain, PolynomialRing):
reconstruction = _rational_reconstruction_int_coeffs
domain = ring.domain.ring
else:
reconstruction = _integer_rational_reconstruction
domain = hm.ring.domain
for monom, coeff in hm.iterterms():
coeffh = reconstruction(coeff, m, domain)
if not coeffh:
return None
h[monom] = coeffh
return h
def _func_field_modgcd_m(f, g, minpoly):
r"""
Compute the GCD of two polynomials in
`\mathbb Q(t_1, \ldots, t_k)[z]/(m_{\alpha}(z))[x]` using a modular
algorithm.
The algorithm computes the GCD of two polynomials `f` and `g` by
calculating the GCD in
`\mathbb Z_p(t_1, \ldots, t_k)[z] / (\check m_{\alpha}(z))[x]` for
suitable primes `p` and the primitive associate `\check m_{\alpha}(z)`
of `m_{\alpha}(z)`. Then the coefficients are reconstructed with the
Chinese Remainder Theorem and Rational Reconstruction. To compute the
GCD over `\mathbb Z_p(t_1, \ldots, t_k)[z] / (\check m_{\alpha})[x]`,
the recursive subroutine ``_func_field_modgcd_p`` is used. To verify the
result in `\mathbb Q(t_1, \ldots, t_k)[z] / (m_{\alpha}(z))[x]`, a
fraction free trial division is used.
Parameters
==========
f, g : PolyElement
polynomials in `\mathbb Z[t_1, \ldots, t_k][x, z]`
minpoly : PolyElement
irreducible polynomial in `\mathbb Z[t_1, \ldots, t_k][z]`
Returns
=======
h : PolyElement
the primitive associate in `\mathbb Z[t_1, \ldots, t_k][x, z]` of
the GCD of `f` and `g`
Examples
========
>>> from sympy.polys.modulargcd import _func_field_modgcd_m
>>> from sympy.polys import ring, ZZ
>>> R, x, z = ring('x, z', ZZ)
>>> minpoly = (z**2 - 2).drop(0)
>>> f = x**2 + 2*x*z + 2
>>> g = x + z
>>> _func_field_modgcd_m(f, g, minpoly)
x + z
>>> D, t = ring('t', ZZ)
>>> R, x, z = ring('x, z', D)
>>> minpoly = (z**2-3).drop(0)
>>> f = x**2 + (t + 1)*x*z + 3*t
>>> g = x*z + 3*t
>>> _func_field_modgcd_m(f, g, minpoly)
x + t*z
References
==========
1. [Hoeij04]_
See also
========
_func_field_modgcd_p
"""
ring = f.ring
domain = ring.domain
if isinstance(domain, PolynomialRing):
k = domain.ngens
QQdomain = domain.ring.clone(domain=domain.domain.get_field())
QQring = ring.clone(domain=QQdomain)
else:
k = 0
QQring = ring.clone(domain=ring.domain.get_field())
cf, f = f.primitive()
cg, g = g.primitive()
# polynomial in Z[t_1, ..., t_k][z]
gamma = ring.dmp_LC(f) * ring.dmp_LC(g)
# polynomial in Z[t_1, ..., t_k]
delta = minpoly.LC
p = 1
primes = []
hplist = []
LMlist = []
while True:
p = nextprime(p)
if gamma.trunc_ground(p) == 0:
continue
if k == 0:
test = (delta % p == 0)
else:
test = (delta.trunc_ground(p) == 0)
if test:
continue
fp = f.trunc_ground(p)
gp = g.trunc_ground(p)
minpolyp = minpoly.trunc_ground(p)
hp = _func_field_modgcd_p(fp, gp, minpolyp, p)
if hp is None:
continue
if hp == 1:
return ring.one
LM = [hp.degree()] + [0]*k
if k > 0:
for monom, coeff in hp.iterterms():
if monom[0] == LM[0] and coeff.LM > tuple(LM[1:]):
LM[1:] = coeff.LM
hm = hp
m = p
for q, hq, LMhq in zip(primes, hplist, LMlist):
if LMhq == LM:
hm = _chinese_remainder_reconstruction_multivariate(hq, hm, q, m)
m *= q
primes.append(p)
hplist.append(hp)
LMlist.append(LM)
hm = _rational_reconstruction_int_coeffs(hm, m, QQring)
if hm is None:
continue
if k == 0:
h = hm.clear_denoms()[1]
else:
den = domain.domain.one
for coeff in hm.itercoeffs():
den = domain.domain.lcm(den, coeff.clear_denoms()[0])
h = hm.mul_ground(den)
# convert back to Z[t_1, ..., t_k][x, z] from Q[t_1, ..., t_k][x, z]
h = h.set_ring(ring)
h = h.primitive()[1]
if not (_trial_division(f.mul_ground(cf), h, minpoly) or
_trial_division(g.mul_ground(cg), h, minpoly)):
return h
def _to_ZZ_poly(f, ring):
r"""
Compute an associate of a polynomial
`f \in \mathbb Q(\alpha)[x_0, \ldots, x_{n-1}]` in
`\mathbb Z[x_1, \ldots, x_{n-1}][z] / (\check m_{\alpha}(z))[x_0]`,
where `\check m_{\alpha}(z) \in \mathbb Z[z]` is the primitive associate
of the minimal polynomial `m_{\alpha}(z)` of `\alpha` over
`\mathbb Q`.
Parameters
==========
f : PolyElement
polynomial in `\mathbb Q(\alpha)[x_0, \ldots, x_{n-1}]`
ring : PolyRing
`\mathbb Z[x_1, \ldots, x_{n-1}][x_0, z]`
Returns
=======
f_ : PolyElement
associate of `f` in
`\mathbb Z[x_1, \ldots, x_{n-1}][x_0, z]`
"""
f_ = ring.zero
if isinstance(ring.domain, PolynomialRing):
domain = ring.domain.domain
else:
domain = ring.domain
den = domain.one
for coeff in f.itercoeffs():
for c in coeff.to_list():
if c:
den = domain.lcm(den, c.denominator)
for monom, coeff in f.iterterms():
coeff = coeff.to_list()
m = ring.domain.one
if isinstance(ring.domain, PolynomialRing):
m = m.mul_monom(monom[1:])
n = len(coeff)
for i in range(n):
if coeff[i]:
c = domain.convert(coeff[i] * den) * m
if (monom[0], n-i-1) not in f_:
f_[(monom[0], n-i-1)] = c
else:
f_[(monom[0], n-i-1)] += c
return f_
def _to_ANP_poly(f, ring):
r"""
Convert a polynomial
`f \in \mathbb Z[x_1, \ldots, x_{n-1}][z]/(\check m_{\alpha}(z))[x_0]`
to a polynomial in `\mathbb Q(\alpha)[x_0, \ldots, x_{n-1}]`,
where `\check m_{\alpha}(z) \in \mathbb Z[z]` is the primitive associate
of the minimal polynomial `m_{\alpha}(z)` of `\alpha` over
`\mathbb Q`.
Parameters
==========
f : PolyElement
polynomial in `\mathbb Z[x_1, \ldots, x_{n-1}][x_0, z]`
ring : PolyRing
`\mathbb Q(\alpha)[x_0, \ldots, x_{n-1}]`
Returns
=======
f_ : PolyElement
polynomial in `\mathbb Q(\alpha)[x_0, \ldots, x_{n-1}]`
"""
domain = ring.domain
f_ = ring.zero
if isinstance(f.ring.domain, PolynomialRing):
for monom, coeff in f.iterterms():
for mon, coef in coeff.iterterms():
m = (monom[0],) + mon
c = domain([domain.domain(coef)] + [0]*monom[1])
if m not in f_:
f_[m] = c
else:
f_[m] += c
else:
for monom, coeff in f.iterterms():
m = (monom[0],)
c = domain([domain.domain(coeff)] + [0]*monom[1])
if m not in f_:
f_[m] = c
else:
f_[m] += c
return f_
def _minpoly_from_dense(minpoly, ring):
r"""
Change representation of the minimal polynomial from ``DMP`` to
``PolyElement`` for a given ring.
"""
minpoly_ = ring.zero
for monom, coeff in minpoly.terms():
minpoly_[monom] = ring.domain(coeff)
return minpoly_
def _primitive_in_x0(f):
r"""
Compute the content in `x_0` and the primitive part of a polynomial `f`
in
`\mathbb Q(\alpha)[x_0, x_1, \ldots, x_{n-1}] \cong \mathbb Q(\alpha)[x_1, \ldots, x_{n-1}][x_0]`.
"""
fring = f.ring
ring = fring.drop_to_ground(*range(1, fring.ngens))
dom = ring.domain.ring
f_ = ring(f.as_expr())
cont = dom.zero
for coeff in f_.itercoeffs():
cont = func_field_modgcd(cont, coeff)[0]
if cont == dom.one:
return cont, f
return cont, f.quo(cont.set_ring(fring))
# TODO: add support for algebraic function fields
def func_field_modgcd(f, g):
r"""
Compute the GCD of two polynomials `f` and `g` in
`\mathbb Q(\alpha)[x_0, \ldots, x_{n-1}]` using a modular algorithm.
The algorithm first computes the primitive associate
`\check m_{\alpha}(z)` of the minimal polynomial `m_{\alpha}` in
`\mathbb{Z}[z]` and the primitive associates of `f` and `g` in
`\mathbb{Z}[x_1, \ldots, x_{n-1}][z]/(\check m_{\alpha})[x_0]`. Then it
computes the GCD in
`\mathbb Q(x_1, \ldots, x_{n-1})[z]/(m_{\alpha}(z))[x_0]`.
This is done by calculating the GCD in
`\mathbb{Z}_p(x_1, \ldots, x_{n-1})[z]/(\check m_{\alpha}(z))[x_0]` for
suitable primes `p` and then reconstructing the coefficients with the
Chinese Remainder Theorem and Rational Reconstuction. The GCD over
`\mathbb{Z}_p(x_1, \ldots, x_{n-1})[z]/(\check m_{\alpha}(z))[x_0]` is
computed with a recursive subroutine, which evaluates the polynomials at
`x_{n-1} = a` for suitable evaluation points `a \in \mathbb Z_p` and
then calls itself recursively until the ground domain does no longer
contain any parameters. For
`\mathbb{Z}_p[z]/(\check m_{\alpha}(z))[x_0]` the Euclidean Algorithm is
used. The results of those recursive calls are then interpolated and
Rational Function Reconstruction is used to obtain the correct
coefficients. The results, both in
`\mathbb Q(x_1, \ldots, x_{n-1})[z]/(m_{\alpha}(z))[x_0]` and
`\mathbb{Z}_p(x_1, \ldots, x_{n-1})[z]/(\check m_{\alpha}(z))[x_0]`, are
verified by a fraction free trial division.
Apart from the above GCD computation some GCDs in
`\mathbb Q(\alpha)[x_1, \ldots, x_{n-1}]` have to be calculated,
because treating the polynomials as univariate ones can result in
a spurious content of the GCD. For this ``func_field_modgcd`` is
called recursively.
Parameters
==========
f, g : PolyElement
polynomials in `\mathbb Q(\alpha)[x_0, \ldots, x_{n-1}]`
Returns
=======
h : PolyElement
monic GCD of the polynomials `f` and `g`
cff : PolyElement
cofactor of `f`, i.e. `\frac f h`
cfg : PolyElement
cofactor of `g`, i.e. `\frac g h`
Examples
========
>>> from sympy.polys.modulargcd import func_field_modgcd
>>> from sympy.polys import AlgebraicField, QQ, ring
>>> from sympy import sqrt
>>> A = AlgebraicField(QQ, sqrt(2))
>>> R, x = ring('x', A)
>>> f = x**2 - 2
>>> g = x + sqrt(2)
>>> h, cff, cfg = func_field_modgcd(f, g)
>>> h == x + sqrt(2)
True
>>> cff * h == f
True
>>> cfg * h == g
True
>>> R, x, y = ring('x, y', A)
>>> f = x**2 + 2*sqrt(2)*x*y + 2*y**2
>>> g = x + sqrt(2)*y
>>> h, cff, cfg = func_field_modgcd(f, g)
>>> h == x + sqrt(2)*y
True
>>> cff * h == f
True
>>> cfg * h == g
True
>>> f = x + sqrt(2)*y
>>> g = x + y
>>> h, cff, cfg = func_field_modgcd(f, g)
>>> h == R.one
True
>>> cff * h == f
True
>>> cfg * h == g
True
References
==========
1. [Hoeij04]_
"""
ring = f.ring
domain = ring.domain
n = ring.ngens
assert ring == g.ring and domain.is_Algebraic
result = _trivial_gcd(f, g)
if result is not None:
return result
z = Dummy('z')
ZZring = ring.clone(symbols=ring.symbols + (z,), domain=domain.domain.get_ring())
if n == 1:
f_ = _to_ZZ_poly(f, ZZring)
g_ = _to_ZZ_poly(g, ZZring)
minpoly = ZZring.drop(0).from_dense(domain.mod.to_list())
h = _func_field_modgcd_m(f_, g_, minpoly)
h = _to_ANP_poly(h, ring)
else:
# contx0f in Q(a)[x_1, ..., x_{n-1}], f in Q(a)[x_0, ..., x_{n-1}]
contx0f, f = _primitive_in_x0(f)
contx0g, g = _primitive_in_x0(g)
contx0h = func_field_modgcd(contx0f, contx0g)[0]
ZZring_ = ZZring.drop_to_ground(*range(1, n))
f_ = _to_ZZ_poly(f, ZZring_)
g_ = _to_ZZ_poly(g, ZZring_)
minpoly = _minpoly_from_dense(domain.mod, ZZring_.drop(0))
h = _func_field_modgcd_m(f_, g_, minpoly)
h = _to_ANP_poly(h, ring)
contx0h_, h = _primitive_in_x0(h)
h *= contx0h.set_ring(ring)
f *= contx0f.set_ring(ring)
g *= contx0g.set_ring(ring)
h = h.quo_ground(h.LC)
return h, f.quo(h), g.quo(h)
PK ]ZZZ�lr�I I sympy/polys/monomials.py"""Tools and arithmetics for monomials of distributed polynomials. """
from itertools import combinations_with_replacement, product
from textwrap import dedent
from sympy.core import Mul, S, Tuple, sympify
from sympy.polys.polyerrors import ExactQuotientFailed
from sympy.polys.polyutils import PicklableWithSlots, dict_from_expr
from sympy.utilities import public
from sympy.utilities.iterables import is_sequence, iterable
@public
def itermonomials(variables, max_degrees, min_degrees=None):
r"""
``max_degrees`` and ``min_degrees`` are either both integers or both lists.
Unless otherwise specified, ``min_degrees`` is either ``0`` or
``[0, ..., 0]``.
A generator of all monomials ``monom`` is returned, such that
either
``min_degree <= total_degree(monom) <= max_degree``,
or
``min_degrees[i] <= degree_list(monom)[i] <= max_degrees[i]``,
for all ``i``.
Case I. ``max_degrees`` and ``min_degrees`` are both integers
=============================================================
Given a set of variables $V$ and a min_degree $N$ and a max_degree $M$
generate a set of monomials of degree less than or equal to $N$ and greater
than or equal to $M$. The total number of monomials in commutative
variables is huge and is given by the following formula if $M = 0$:
.. math::
\frac{(\#V + N)!}{\#V! N!}
For example if we would like to generate a dense polynomial of
a total degree $N = 50$ and $M = 0$, which is the worst case, in 5
variables, assuming that exponents and all of coefficients are 32-bit long
and stored in an array we would need almost 80 GiB of memory! Fortunately
most polynomials, that we will encounter, are sparse.
Consider monomials in commutative variables $x$ and $y$
and non-commutative variables $a$ and $b$::
>>> from sympy import symbols
>>> from sympy.polys.monomials import itermonomials
>>> from sympy.polys.orderings import monomial_key
>>> from sympy.abc import x, y
>>> sorted(itermonomials([x, y], 2), key=monomial_key('grlex', [y, x]))
[1, x, y, x**2, x*y, y**2]
>>> sorted(itermonomials([x, y], 3), key=monomial_key('grlex', [y, x]))
[1, x, y, x**2, x*y, y**2, x**3, x**2*y, x*y**2, y**3]
>>> a, b = symbols('a, b', commutative=False)
>>> set(itermonomials([a, b, x], 2))
{1, a, a**2, b, b**2, x, x**2, a*b, b*a, x*a, x*b}
>>> sorted(itermonomials([x, y], 2, 1), key=monomial_key('grlex', [y, x]))
[x, y, x**2, x*y, y**2]
Case II. ``max_degrees`` and ``min_degrees`` are both lists
===========================================================
If ``max_degrees = [d_1, ..., d_n]`` and
``min_degrees = [e_1, ..., e_n]``, the number of monomials generated
is:
.. math::
(d_1 - e_1 + 1) (d_2 - e_2 + 1) \cdots (d_n - e_n + 1)
Let us generate all monomials ``monom`` in variables $x$ and $y$
such that ``[1, 2][i] <= degree_list(monom)[i] <= [2, 4][i]``,
``i = 0, 1`` ::
>>> from sympy import symbols
>>> from sympy.polys.monomials import itermonomials
>>> from sympy.polys.orderings import monomial_key
>>> from sympy.abc import x, y
>>> sorted(itermonomials([x, y], [2, 4], [1, 2]), reverse=True, key=monomial_key('lex', [x, y]))
[x**2*y**4, x**2*y**3, x**2*y**2, x*y**4, x*y**3, x*y**2]
"""
n = len(variables)
if is_sequence(max_degrees):
if len(max_degrees) != n:
raise ValueError('Argument sizes do not match')
if min_degrees is None:
min_degrees = [0]*n
elif not is_sequence(min_degrees):
raise ValueError('min_degrees is not a list')
else:
if len(min_degrees) != n:
raise ValueError('Argument sizes do not match')
if any(i < 0 for i in min_degrees):
raise ValueError("min_degrees cannot contain negative numbers")
total_degree = False
else:
max_degree = max_degrees
if max_degree < 0:
raise ValueError("max_degrees cannot be negative")
if min_degrees is None:
min_degree = 0
else:
if min_degrees < 0:
raise ValueError("min_degrees cannot be negative")
min_degree = min_degrees
total_degree = True
if total_degree:
if min_degree > max_degree:
return
if not variables or max_degree == 0:
yield S.One
return
# Force to list in case of passed tuple or other incompatible collection
variables = list(variables) + [S.One]
if all(variable.is_commutative for variable in variables):
monomials_list_comm = []
for item in combinations_with_replacement(variables, max_degree):
powers = dict.fromkeys(variables, 0)
for variable in item:
if variable != 1:
powers[variable] += 1
if sum(powers.values()) >= min_degree:
monomials_list_comm.append(Mul(*item))
yield from set(monomials_list_comm)
else:
monomials_list_non_comm = []
for item in product(variables, repeat=max_degree):
powers = dict.fromkeys(variables, 0)
for variable in item:
if variable != 1:
powers[variable] += 1
if sum(powers.values()) >= min_degree:
monomials_list_non_comm.append(Mul(*item))
yield from set(monomials_list_non_comm)
else:
if any(min_degrees[i] > max_degrees[i] for i in range(n)):
raise ValueError('min_degrees[i] must be <= max_degrees[i] for all i')
power_lists = []
for var, min_d, max_d in zip(variables, min_degrees, max_degrees):
power_lists.append([var**i for i in range(min_d, max_d + 1)])
for powers in product(*power_lists):
yield Mul(*powers)
def monomial_count(V, N):
r"""
Computes the number of monomials.
The number of monomials is given by the following formula:
.. math::
\frac{(\#V + N)!}{\#V! N!}
where `N` is a total degree and `V` is a set of variables.
Examples
========
>>> from sympy.polys.monomials import itermonomials, monomial_count
>>> from sympy.polys.orderings import monomial_key
>>> from sympy.abc import x, y
>>> monomial_count(2, 2)
6
>>> M = list(itermonomials([x, y], 2))
>>> sorted(M, key=monomial_key('grlex', [y, x]))
[1, x, y, x**2, x*y, y**2]
>>> len(M)
6
"""
from sympy.functions.combinatorial.factorials import factorial
return factorial(V + N) / factorial(V) / factorial(N)
def monomial_mul(A, B):
"""
Multiplication of tuples representing monomials.
Examples
========
Lets multiply `x**3*y**4*z` with `x*y**2`::
>>> from sympy.polys.monomials import monomial_mul
>>> monomial_mul((3, 4, 1), (1, 2, 0))
(4, 6, 1)
which gives `x**4*y**5*z`.
"""
return tuple([ a + b for a, b in zip(A, B) ])
def monomial_div(A, B):
"""
Division of tuples representing monomials.
Examples
========
Lets divide `x**3*y**4*z` by `x*y**2`::
>>> from sympy.polys.monomials import monomial_div
>>> monomial_div((3, 4, 1), (1, 2, 0))
(2, 2, 1)
which gives `x**2*y**2*z`. However::
>>> monomial_div((3, 4, 1), (1, 2, 2)) is None
True
`x*y**2*z**2` does not divide `x**3*y**4*z`.
"""
C = monomial_ldiv(A, B)
if all(c >= 0 for c in C):
return tuple(C)
else:
return None
def monomial_ldiv(A, B):
"""
Division of tuples representing monomials.
Examples
========
Lets divide `x**3*y**4*z` by `x*y**2`::
>>> from sympy.polys.monomials import monomial_ldiv
>>> monomial_ldiv((3, 4, 1), (1, 2, 0))
(2, 2, 1)
which gives `x**2*y**2*z`.
>>> monomial_ldiv((3, 4, 1), (1, 2, 2))
(2, 2, -1)
which gives `x**2*y**2*z**-1`.
"""
return tuple([ a - b for a, b in zip(A, B) ])
def monomial_pow(A, n):
"""Return the n-th pow of the monomial. """
return tuple([ a*n for a in A ])
def monomial_gcd(A, B):
"""
Greatest common divisor of tuples representing monomials.
Examples
========
Lets compute GCD of `x*y**4*z` and `x**3*y**2`::
>>> from sympy.polys.monomials import monomial_gcd
>>> monomial_gcd((1, 4, 1), (3, 2, 0))
(1, 2, 0)
which gives `x*y**2`.
"""
return tuple([ min(a, b) for a, b in zip(A, B) ])
def monomial_lcm(A, B):
"""
Least common multiple of tuples representing monomials.
Examples
========
Lets compute LCM of `x*y**4*z` and `x**3*y**2`::
>>> from sympy.polys.monomials import monomial_lcm
>>> monomial_lcm((1, 4, 1), (3, 2, 0))
(3, 4, 1)
which gives `x**3*y**4*z`.
"""
return tuple([ max(a, b) for a, b in zip(A, B) ])
def monomial_divides(A, B):
"""
Does there exist a monomial X such that XA == B?
Examples
========
>>> from sympy.polys.monomials import monomial_divides
>>> monomial_divides((1, 2), (3, 4))
True
>>> monomial_divides((1, 2), (0, 2))
False
"""
return all(a <= b for a, b in zip(A, B))
def monomial_max(*monoms):
"""
Returns maximal degree for each variable in a set of monomials.
Examples
========
Consider monomials `x**3*y**4*z**5`, `y**5*z` and `x**6*y**3*z**9`.
We wish to find out what is the maximal degree for each of `x`, `y`
and `z` variables::
>>> from sympy.polys.monomials import monomial_max
>>> monomial_max((3,4,5), (0,5,1), (6,3,9))
(6, 5, 9)
"""
M = list(monoms[0])
for N in monoms[1:]:
for i, n in enumerate(N):
M[i] = max(M[i], n)
return tuple(M)
def monomial_min(*monoms):
"""
Returns minimal degree for each variable in a set of monomials.
Examples
========
Consider monomials `x**3*y**4*z**5`, `y**5*z` and `x**6*y**3*z**9`.
We wish to find out what is the minimal degree for each of `x`, `y`
and `z` variables::
>>> from sympy.polys.monomials import monomial_min
>>> monomial_min((3,4,5), (0,5,1), (6,3,9))
(0, 3, 1)
"""
M = list(monoms[0])
for N in monoms[1:]:
for i, n in enumerate(N):
M[i] = min(M[i], n)
return tuple(M)
def monomial_deg(M):
"""
Returns the total degree of a monomial.
Examples
========
The total degree of `xy^2` is 3:
>>> from sympy.polys.monomials import monomial_deg
>>> monomial_deg((1, 2))
3
"""
return sum(M)
def term_div(a, b, domain):
"""Division of two terms in over a ring/field. """
a_lm, a_lc = a
b_lm, b_lc = b
monom = monomial_div(a_lm, b_lm)
if domain.is_Field:
if monom is not None:
return monom, domain.quo(a_lc, b_lc)
else:
return None
else:
if not (monom is None or a_lc % b_lc):
return monom, domain.quo(a_lc, b_lc)
else:
return None
class MonomialOps:
"""Code generator of fast monomial arithmetic functions. """
def __init__(self, ngens):
self.ngens = ngens
def _build(self, code, name):
ns = {}
exec(code, ns)
return ns[name]
def _vars(self, name):
return [ "%s%s" % (name, i) for i in range(self.ngens) ]
def mul(self):
name = "monomial_mul"
template = dedent("""\
def %(name)s(A, B):
(%(A)s,) = A
(%(B)s,) = B
return (%(AB)s,)
""")
A = self._vars("a")
B = self._vars("b")
AB = [ "%s + %s" % (a, b) for a, b in zip(A, B) ]
code = template % {"name": name, "A": ", ".join(A), "B": ", ".join(B), "AB": ", ".join(AB)}
return self._build(code, name)
def pow(self):
name = "monomial_pow"
template = dedent("""\
def %(name)s(A, k):
(%(A)s,) = A
return (%(Ak)s,)
""")
A = self._vars("a")
Ak = [ "%s*k" % a for a in A ]
code = template % {"name": name, "A": ", ".join(A), "Ak": ", ".join(Ak)}
return self._build(code, name)
def mulpow(self):
name = "monomial_mulpow"
template = dedent("""\
def %(name)s(A, B, k):
(%(A)s,) = A
(%(B)s,) = B
return (%(ABk)s,)
""")
A = self._vars("a")
B = self._vars("b")
ABk = [ "%s + %s*k" % (a, b) for a, b in zip(A, B) ]
code = template % {"name": name, "A": ", ".join(A), "B": ", ".join(B), "ABk": ", ".join(ABk)}
return self._build(code, name)
def ldiv(self):
name = "monomial_ldiv"
template = dedent("""\
def %(name)s(A, B):
(%(A)s,) = A
(%(B)s,) = B
return (%(AB)s,)
""")
A = self._vars("a")
B = self._vars("b")
AB = [ "%s - %s" % (a, b) for a, b in zip(A, B) ]
code = template % {"name": name, "A": ", ".join(A), "B": ", ".join(B), "AB": ", ".join(AB)}
return self._build(code, name)
def div(self):
name = "monomial_div"
template = dedent("""\
def %(name)s(A, B):
(%(A)s,) = A
(%(B)s,) = B
%(RAB)s
return (%(R)s,)
""")
A = self._vars("a")
B = self._vars("b")
RAB = [ "r%(i)s = a%(i)s - b%(i)s\n if r%(i)s < 0: return None" % {"i": i} for i in range(self.ngens) ]
R = self._vars("r")
code = template % {"name": name, "A": ", ".join(A), "B": ", ".join(B), "RAB": "\n ".join(RAB), "R": ", ".join(R)}
return self._build(code, name)
def lcm(self):
name = "monomial_lcm"
template = dedent("""\
def %(name)s(A, B):
(%(A)s,) = A
(%(B)s,) = B
return (%(AB)s,)
""")
A = self._vars("a")
B = self._vars("b")
AB = [ "%s if %s >= %s else %s" % (a, a, b, b) for a, b in zip(A, B) ]
code = template % {"name": name, "A": ", ".join(A), "B": ", ".join(B), "AB": ", ".join(AB)}
return self._build(code, name)
def gcd(self):
name = "monomial_gcd"
template = dedent("""\
def %(name)s(A, B):
(%(A)s,) = A
(%(B)s,) = B
return (%(AB)s,)
""")
A = self._vars("a")
B = self._vars("b")
AB = [ "%s if %s <= %s else %s" % (a, a, b, b) for a, b in zip(A, B) ]
code = template % {"name": name, "A": ", ".join(A), "B": ", ".join(B), "AB": ", ".join(AB)}
return self._build(code, name)
@public
class Monomial(PicklableWithSlots):
"""Class representing a monomial, i.e. a product of powers. """
__slots__ = ('exponents', 'gens')
def __init__(self, monom, gens=None):
if not iterable(monom):
rep, gens = dict_from_expr(sympify(monom), gens=gens)
if len(rep) == 1 and list(rep.values())[0] == 1:
monom = list(rep.keys())[0]
else:
raise ValueError("Expected a monomial got {}".format(monom))
self.exponents = tuple(map(int, monom))
self.gens = gens
def rebuild(self, exponents, gens=None):
return self.__class__(exponents, gens or self.gens)
def __len__(self):
return len(self.exponents)
def __iter__(self):
return iter(self.exponents)
def __getitem__(self, item):
return self.exponents[item]
def __hash__(self):
return hash((self.__class__.__name__, self.exponents, self.gens))
def __str__(self):
if self.gens:
return "*".join([ "%s**%s" % (gen, exp) for gen, exp in zip(self.gens, self.exponents) ])
else:
return "%s(%s)" % (self.__class__.__name__, self.exponents)
def as_expr(self, *gens):
"""Convert a monomial instance to a SymPy expression. """
gens = gens or self.gens
if not gens:
raise ValueError(
"Cannot convert %s to an expression without generators" % self)
return Mul(*[ gen**exp for gen, exp in zip(gens, self.exponents) ])
def __eq__(self, other):
if isinstance(other, Monomial):
exponents = other.exponents
elif isinstance(other, (tuple, Tuple)):
exponents = other
else:
return False
return self.exponents == exponents
def __ne__(self, other):
return not self == other
def __mul__(self, other):
if isinstance(other, Monomial):
exponents = other.exponents
elif isinstance(other, (tuple, Tuple)):
exponents = other
else:
raise NotImplementedError
return self.rebuild(monomial_mul(self.exponents, exponents))
def __truediv__(self, other):
if isinstance(other, Monomial):
exponents = other.exponents
elif isinstance(other, (tuple, Tuple)):
exponents = other
else:
raise NotImplementedError
result = monomial_div(self.exponents, exponents)
if result is not None:
return self.rebuild(result)
else:
raise ExactQuotientFailed(self, Monomial(other))
__floordiv__ = __truediv__
def __pow__(self, other):
n = int(other)
if n < 0:
raise ValueError("a non-negative integer expected, got %s" % other)
return self.rebuild(monomial_pow(self.exponents, n))
def gcd(self, other):
"""Greatest common divisor of monomials. """
if isinstance(other, Monomial):
exponents = other.exponents
elif isinstance(other, (tuple, Tuple)):
exponents = other
else:
raise TypeError(
"an instance of Monomial class expected, got %s" % other)
return self.rebuild(monomial_gcd(self.exponents, exponents))
def lcm(self, other):
"""Least common multiple of monomials. """
if isinstance(other, Monomial):
exponents = other.exponents
elif isinstance(other, (tuple, Tuple)):
exponents = other
else:
raise TypeError(
"an instance of Monomial class expected, got %s" % other)
return self.rebuild(monomial_lcm(self.exponents, exponents))
PK ]ZZZ+; �; & sympy/polys/multivariate_resultants.py"""
This module contains functions for two multivariate resultants. These
are:
- Dixon's resultant.
- Macaulay's resultant.
Multivariate resultants are used to identify whether a multivariate
system has common roots. That is when the resultant is equal to zero.
"""
from math import prod
from sympy.core.mul import Mul
from sympy.matrices.dense import (Matrix, diag)
from sympy.polys.polytools import (Poly, degree_list, rem)
from sympy.simplify.simplify import simplify
from sympy.tensor.indexed import IndexedBase
from sympy.polys.monomials import itermonomials, monomial_deg
from sympy.polys.orderings import monomial_key
from sympy.polys.polytools import poly_from_expr, total_degree
from sympy.functions.combinatorial.factorials import binomial
from itertools import combinations_with_replacement
from sympy.utilities.exceptions import sympy_deprecation_warning
class DixonResultant():
"""
A class for retrieving the Dixon's resultant of a multivariate
system.
Examples
========
>>> from sympy import symbols
>>> from sympy.polys.multivariate_resultants import DixonResultant
>>> x, y = symbols('x, y')
>>> p = x + y
>>> q = x ** 2 + y ** 3
>>> h = x ** 2 + y
>>> dixon = DixonResultant(variables=[x, y], polynomials=[p, q, h])
>>> poly = dixon.get_dixon_polynomial()
>>> matrix = dixon.get_dixon_matrix(polynomial=poly)
>>> matrix
Matrix([
[ 0, 0, -1, 0, -1],
[ 0, -1, 0, -1, 0],
[-1, 0, 1, 0, 0],
[ 0, -1, 0, 0, 1],
[-1, 0, 0, 1, 0]])
>>> matrix.det()
0
See Also
========
Notebook in examples: sympy/example/notebooks.
References
==========
.. [1] [Kapur1994]_
.. [2] [Palancz08]_
"""
def __init__(self, polynomials, variables):
"""
A class that takes two lists, a list of polynomials and list of
variables. Returns the Dixon matrix of the multivariate system.
Parameters
----------
polynomials : list of polynomials
A list of m n-degree polynomials
variables: list
A list of all n variables
"""
self.polynomials = polynomials
self.variables = variables
self.n = len(self.variables)
self.m = len(self.polynomials)
a = IndexedBase("alpha")
# A list of n alpha variables (the replacing variables)
self.dummy_variables = [a[i] for i in range(self.n)]
# A list of the d_max of each variable.
self._max_degrees = [max(degree_list(poly)[i] for poly in self.polynomials)
for i in range(self.n)]
@property
def max_degrees(self):
sympy_deprecation_warning(
"""
The max_degrees property of DixonResultant is deprecated.
""",
deprecated_since_version="1.5",
active_deprecations_target="deprecated-dixonresultant-properties",
)
return self._max_degrees
def get_dixon_polynomial(self):
r"""
Returns
=======
dixon_polynomial: polynomial
Dixon's polynomial is calculated as:
delta = Delta(A) / ((x_1 - a_1) ... (x_n - a_n)) where,
A = |p_1(x_1,... x_n), ..., p_n(x_1,... x_n)|
|p_1(a_1,... x_n), ..., p_n(a_1,... x_n)|
|... , ..., ...|
|p_1(a_1,... a_n), ..., p_n(a_1,... a_n)|
"""
if self.m != (self.n + 1):
raise ValueError('Method invalid for given combination.')
# First row
rows = [self.polynomials]
temp = list(self.variables)
for idx in range(self.n):
temp[idx] = self.dummy_variables[idx]
substitution = dict(zip(self.variables, temp))
rows.append([f.subs(substitution) for f in self.polynomials])
A = Matrix(rows)
terms = zip(self.variables, self.dummy_variables)
product_of_differences = Mul(*[a - b for a, b in terms])
dixon_polynomial = (A.det() / product_of_differences).factor()
return poly_from_expr(dixon_polynomial, self.dummy_variables)[0]
def get_upper_degree(self):
sympy_deprecation_warning(
"""
The get_upper_degree() method of DixonResultant is deprecated. Use
get_max_degrees() instead.
""",
deprecated_since_version="1.5",
active_deprecations_target="deprecated-dixonresultant-properties"
)
list_of_products = [self.variables[i] ** self._max_degrees[i]
for i in range(self.n)]
product = prod(list_of_products)
product = Poly(product).monoms()
return monomial_deg(*product)
def get_max_degrees(self, polynomial):
r"""
Returns a list of the maximum degree of each variable appearing
in the coefficients of the Dixon polynomial. The coefficients are
viewed as polys in $x_1, x_2, \dots, x_n$.
"""
deg_lists = [degree_list(Poly(poly, self.variables))
for poly in polynomial.coeffs()]
max_degrees = [max(degs) for degs in zip(*deg_lists)]
return max_degrees
def get_dixon_matrix(self, polynomial):
r"""
Construct the Dixon matrix from the coefficients of polynomial
\alpha. Each coefficient is viewed as a polynomial of x_1, ...,
x_n.
"""
max_degrees = self.get_max_degrees(polynomial)
# list of column headers of the Dixon matrix.
monomials = itermonomials(self.variables, max_degrees)
monomials = sorted(monomials, reverse=True,
key=monomial_key('lex', self.variables))
dixon_matrix = Matrix([[Poly(c, *self.variables).coeff_monomial(m)
for m in monomials]
for c in polynomial.coeffs()])
# remove columns if needed
if dixon_matrix.shape[0] != dixon_matrix.shape[1]:
keep = [column for column in range(dixon_matrix.shape[-1])
if any(element != 0 for element
in dixon_matrix[:, column])]
dixon_matrix = dixon_matrix[:, keep]
return dixon_matrix
def KSY_precondition(self, matrix):
"""
Test for the validity of the Kapur-Saxena-Yang precondition.
The precondition requires that the column corresponding to the
monomial 1 = x_1 ^ 0 * x_2 ^ 0 * ... * x_n ^ 0 is not a linear
combination of the remaining ones. In SymPy notation this is
the last column. For the precondition to hold the last non-zero
row of the rref matrix should be of the form [0, 0, ..., 1].
"""
if matrix.is_zero_matrix:
return False
m, n = matrix.shape
# simplify the matrix and keep only its non-zero rows
matrix = simplify(matrix.rref()[0])
rows = [i for i in range(m) if any(matrix[i, j] != 0 for j in range(n))]
matrix = matrix[rows,:]
condition = Matrix([[0]*(n-1) + [1]])
if matrix[-1,:] == condition:
return True
else:
return False
def delete_zero_rows_and_columns(self, matrix):
"""Remove the zero rows and columns of the matrix."""
rows = [
i for i in range(matrix.rows) if not matrix.row(i).is_zero_matrix]
cols = [
j for j in range(matrix.cols) if not matrix.col(j).is_zero_matrix]
return matrix[rows, cols]
def product_leading_entries(self, matrix):
"""Calculate the product of the leading entries of the matrix."""
res = 1
for row in range(matrix.rows):
for el in matrix.row(row):
if el != 0:
res = res * el
break
return res
def get_KSY_Dixon_resultant(self, matrix):
"""Calculate the Kapur-Saxena-Yang approach to the Dixon Resultant."""
matrix = self.delete_zero_rows_and_columns(matrix)
_, U, _ = matrix.LUdecomposition()
matrix = self.delete_zero_rows_and_columns(simplify(U))
return self.product_leading_entries(matrix)
class MacaulayResultant():
"""
A class for calculating the Macaulay resultant. Note that the
polynomials must be homogenized and their coefficients must be
given as symbols.
Examples
========
>>> from sympy import symbols
>>> from sympy.polys.multivariate_resultants import MacaulayResultant
>>> x, y, z = symbols('x, y, z')
>>> a_0, a_1, a_2 = symbols('a_0, a_1, a_2')
>>> b_0, b_1, b_2 = symbols('b_0, b_1, b_2')
>>> c_0, c_1, c_2,c_3, c_4 = symbols('c_0, c_1, c_2, c_3, c_4')
>>> f = a_0 * y - a_1 * x + a_2 * z
>>> g = b_1 * x ** 2 + b_0 * y ** 2 - b_2 * z ** 2
>>> h = c_0 * y * z ** 2 - c_1 * x ** 3 + c_2 * x ** 2 * z - c_3 * x * z ** 2 + c_4 * z ** 3
>>> mac = MacaulayResultant(polynomials=[f, g, h], variables=[x, y, z])
>>> mac.monomial_set
[x**4, x**3*y, x**3*z, x**2*y**2, x**2*y*z, x**2*z**2, x*y**3,
x*y**2*z, x*y*z**2, x*z**3, y**4, y**3*z, y**2*z**2, y*z**3, z**4]
>>> matrix = mac.get_matrix()
>>> submatrix = mac.get_submatrix(matrix)
>>> submatrix
Matrix([
[-a_1, a_0, a_2, 0],
[ 0, -a_1, 0, 0],
[ 0, 0, -a_1, 0],
[ 0, 0, 0, -a_1]])
See Also
========
Notebook in examples: sympy/example/notebooks.
References
==========
.. [1] [Bruce97]_
.. [2] [Stiller96]_
"""
def __init__(self, polynomials, variables):
"""
Parameters
==========
variables: list
A list of all n variables
polynomials : list of SymPy polynomials
A list of m n-degree polynomials
"""
self.polynomials = polynomials
self.variables = variables
self.n = len(variables)
# A list of the d_max of each polynomial.
self.degrees = [total_degree(poly, *self.variables) for poly
in self.polynomials]
self.degree_m = self._get_degree_m()
self.monomials_size = self.get_size()
# The set T of all possible monomials of degree degree_m
self.monomial_set = self.get_monomials_of_certain_degree(self.degree_m)
def _get_degree_m(self):
r"""
Returns
=======
degree_m: int
The degree_m is calculated as 1 + \sum_1 ^ n (d_i - 1),
where d_i is the degree of the i polynomial
"""
return 1 + sum(d - 1 for d in self.degrees)
def get_size(self):
r"""
Returns
=======
size: int
The size of set T. Set T is the set of all possible
monomials of the n variables for degree equal to the
degree_m
"""
return binomial(self.degree_m + self.n - 1, self.n - 1)
def get_monomials_of_certain_degree(self, degree):
"""
Returns
=======
monomials: list
A list of monomials of a certain degree.
"""
monomials = [Mul(*monomial) for monomial
in combinations_with_replacement(self.variables,
degree)]
return sorted(monomials, reverse=True,
key=monomial_key('lex', self.variables))
def get_row_coefficients(self):
"""
Returns
=======
row_coefficients: list
The row coefficients of Macaulay's matrix
"""
row_coefficients = []
divisible = []
for i in range(self.n):
if i == 0:
degree = self.degree_m - self.degrees[i]
monomial = self.get_monomials_of_certain_degree(degree)
row_coefficients.append(monomial)
else:
divisible.append(self.variables[i - 1] **
self.degrees[i - 1])
degree = self.degree_m - self.degrees[i]
poss_rows = self.get_monomials_of_certain_degree(degree)
for div in divisible:
for p in poss_rows:
if rem(p, div) == 0:
poss_rows = [item for item in poss_rows
if item != p]
row_coefficients.append(poss_rows)
return row_coefficients
def get_matrix(self):
"""
Returns
=======
macaulay_matrix: Matrix
The Macaulay numerator matrix
"""
rows = []
row_coefficients = self.get_row_coefficients()
for i in range(self.n):
for multiplier in row_coefficients[i]:
coefficients = []
poly = Poly(self.polynomials[i] * multiplier,
*self.variables)
for mono in self.monomial_set:
coefficients.append(poly.coeff_monomial(mono))
rows.append(coefficients)
macaulay_matrix = Matrix(rows)
return macaulay_matrix
def get_reduced_nonreduced(self):
r"""
Returns
=======
reduced: list
A list of the reduced monomials
non_reduced: list
A list of the monomials that are not reduced
Definition
==========
A polynomial is said to be reduced in x_i, if its degree (the
maximum degree of its monomials) in x_i is less than d_i. A
polynomial that is reduced in all variables but one is said
simply to be reduced.
"""
divisible = []
for m in self.monomial_set:
temp = []
for i, v in enumerate(self.variables):
temp.append(bool(total_degree(m, v) >= self.degrees[i]))
divisible.append(temp)
reduced = [i for i, r in enumerate(divisible)
if sum(r) < self.n - 1]
non_reduced = [i for i, r in enumerate(divisible)
if sum(r) >= self.n -1]
return reduced, non_reduced
def get_submatrix(self, matrix):
r"""
Returns
=======
macaulay_submatrix: Matrix
The Macaulay denominator matrix. Columns that are non reduced are kept.
The row which contains one of the a_{i}s is dropped. a_{i}s
are the coefficients of x_i ^ {d_i}.
"""
reduced, non_reduced = self.get_reduced_nonreduced()
# if reduced == [], then det(matrix) should be 1
if reduced == []:
return diag([1])
# reduced != []
reduction_set = [v ** self.degrees[i] for i, v
in enumerate(self.variables)]
ais = [self.polynomials[i].coeff(reduction_set[i])
for i in range(self.n)]
reduced_matrix = matrix[:, reduced]
keep = []
for row in range(reduced_matrix.rows):
check = [ai in reduced_matrix[row, :] for ai in ais]
if True not in check:
keep.append(row)
return matrix[keep, non_reduced]
PK ]ZZZ�\/4! 4! sympy/polys/orderings.py"""Definitions of monomial orderings. """
from __future__ import annotations
__all__ = ["lex", "grlex", "grevlex", "ilex", "igrlex", "igrevlex"]
from sympy.core import Symbol
from sympy.utilities.iterables import iterable
class MonomialOrder:
"""Base class for monomial orderings. """
alias: str | None = None
is_global: bool | None = None
is_default = False
def __repr__(self):
return self.__class__.__name__ + "()"
def __str__(self):
return self.alias
def __call__(self, monomial):
raise NotImplementedError
def __eq__(self, other):
return self.__class__ == other.__class__
def __hash__(self):
return hash(self.__class__)
def __ne__(self, other):
return not (self == other)
class LexOrder(MonomialOrder):
"""Lexicographic order of monomials. """
alias = 'lex'
is_global = True
is_default = True
def __call__(self, monomial):
return monomial
class GradedLexOrder(MonomialOrder):
"""Graded lexicographic order of monomials. """
alias = 'grlex'
is_global = True
def __call__(self, monomial):
return (sum(monomial), monomial)
class ReversedGradedLexOrder(MonomialOrder):
"""Reversed graded lexicographic order of monomials. """
alias = 'grevlex'
is_global = True
def __call__(self, monomial):
return (sum(monomial), tuple(reversed([-m for m in monomial])))
class ProductOrder(MonomialOrder):
"""
A product order built from other monomial orders.
Given (not necessarily total) orders O1, O2, ..., On, their product order
P is defined as M1 > M2 iff there exists i such that O1(M1) = O2(M2),
..., Oi(M1) = Oi(M2), O{i+1}(M1) > O{i+1}(M2).
Product orders are typically built from monomial orders on different sets
of variables.
ProductOrder is constructed by passing a list of pairs
[(O1, L1), (O2, L2), ...] where Oi are MonomialOrders and Li are callables.
Upon comparison, the Li are passed the total monomial, and should filter
out the part of the monomial to pass to Oi.
Examples
========
We can use a lexicographic order on x_1, x_2 and also on
y_1, y_2, y_3, and their product on {x_i, y_i} as follows:
>>> from sympy.polys.orderings import lex, grlex, ProductOrder
>>> P = ProductOrder(
... (lex, lambda m: m[:2]), # lex order on x_1 and x_2 of monomial
... (grlex, lambda m: m[2:]) # grlex on y_1, y_2, y_3
... )
>>> P((2, 1, 1, 0, 0)) > P((1, 10, 0, 2, 0))
True
Here the exponent `2` of `x_1` in the first monomial
(`x_1^2 x_2 y_1`) is bigger than the exponent `1` of `x_1` in the
second monomial (`x_1 x_2^10 y_2^2`), so the first monomial is greater
in the product ordering.
>>> P((2, 1, 1, 0, 0)) < P((2, 1, 0, 2, 0))
True
Here the exponents of `x_1` and `x_2` agree, so the grlex order on
`y_1, y_2, y_3` is used to decide the ordering. In this case the monomial
`y_2^2` is ordered larger than `y_1`, since for the grlex order the degree
of the monomial is most important.
"""
def __init__(self, *args):
self.args = args
def __call__(self, monomial):
return tuple(O(lamda(monomial)) for (O, lamda) in self.args)
def __repr__(self):
contents = [repr(x[0]) for x in self.args]
return self.__class__.__name__ + '(' + ", ".join(contents) + ')'
def __str__(self):
contents = [str(x[0]) for x in self.args]
return self.__class__.__name__ + '(' + ", ".join(contents) + ')'
def __eq__(self, other):
if not isinstance(other, ProductOrder):
return False
return self.args == other.args
def __hash__(self):
return hash((self.__class__, self.args))
@property
def is_global(self):
if all(o.is_global is True for o, _ in self.args):
return True
if all(o.is_global is False for o, _ in self.args):
return False
return None
class InverseOrder(MonomialOrder):
"""
The "inverse" of another monomial order.
If O is any monomial order, we can construct another monomial order iO
such that `A >_{iO} B` if and only if `B >_O A`. This is useful for
constructing local orders.
Note that many algorithms only work with *global* orders.
For example, in the inverse lexicographic order on a single variable `x`,
high powers of `x` count as small:
>>> from sympy.polys.orderings import lex, InverseOrder
>>> ilex = InverseOrder(lex)
>>> ilex((5,)) < ilex((0,))
True
"""
def __init__(self, O):
self.O = O
def __str__(self):
return "i" + str(self.O)
def __call__(self, monomial):
def inv(l):
if iterable(l):
return tuple(inv(x) for x in l)
return -l
return inv(self.O(monomial))
@property
def is_global(self):
if self.O.is_global is True:
return False
if self.O.is_global is False:
return True
return None
def __eq__(self, other):
return isinstance(other, InverseOrder) and other.O == self.O
def __hash__(self):
return hash((self.__class__, self.O))
lex = LexOrder()
grlex = GradedLexOrder()
grevlex = ReversedGradedLexOrder()
ilex = InverseOrder(lex)
igrlex = InverseOrder(grlex)
igrevlex = InverseOrder(grevlex)
_monomial_key = {
'lex': lex,
'grlex': grlex,
'grevlex': grevlex,
'ilex': ilex,
'igrlex': igrlex,
'igrevlex': igrevlex
}
def monomial_key(order=None, gens=None):
"""
Return a function defining admissible order on monomials.
The result of a call to :func:`monomial_key` is a function which should
be used as a key to :func:`sorted` built-in function, to provide order
in a set of monomials of the same length.
Currently supported monomial orderings are:
1. lex - lexicographic order (default)
2. grlex - graded lexicographic order
3. grevlex - reversed graded lexicographic order
4. ilex, igrlex, igrevlex - the corresponding inverse orders
If the ``order`` input argument is not a string but has ``__call__``
attribute, then it will pass through with an assumption that the
callable object defines an admissible order on monomials.
If the ``gens`` input argument contains a list of generators, the
resulting key function can be used to sort SymPy ``Expr`` objects.
"""
if order is None:
order = lex
if isinstance(order, Symbol):
order = str(order)
if isinstance(order, str):
try:
order = _monomial_key[order]
except KeyError:
raise ValueError("supported monomial orderings are 'lex', 'grlex' and 'grevlex', got %r" % order)
if hasattr(order, '__call__'):
if gens is not None:
def _order(expr):
return order(expr.as_poly(*gens).degree_list())
return _order
return order
else:
raise ValueError("monomial ordering specification must be a string or a callable, got %s" % order)
class _ItemGetter:
"""Helper class to return a subsequence of values."""
def __init__(self, seq):
self.seq = tuple(seq)
def __call__(self, m):
return tuple(m[idx] for idx in self.seq)
def __eq__(self, other):
if not isinstance(other, _ItemGetter):
return False
return self.seq == other.seq
def build_product_order(arg, gens):
"""
Build a monomial order on ``gens``.
``arg`` should be a tuple of iterables. The first element of each iterable
should be a string or monomial order (will be passed to monomial_key),
the others should be subsets of the generators. This function will build
the corresponding product order.
For example, build a product of two grlex orders:
>>> from sympy.polys.orderings import build_product_order
>>> from sympy.abc import x, y, z, t
>>> O = build_product_order((("grlex", x, y), ("grlex", z, t)), [x, y, z, t])
>>> O((1, 2, 3, 4))
((3, (1, 2)), (7, (3, 4)))
"""
gens2idx = {}
for i, g in enumerate(gens):
gens2idx[g] = i
order = []
for expr in arg:
name = expr[0]
var = expr[1:]
def makelambda(var):
return _ItemGetter(gens2idx[g] for g in var)
order.append((monomial_key(name), makelambda(var)))
return ProductOrder(*order)
PK ]ZZZ�����' �' sympy/polys/orthopolys.py"""Efficient functions for generating orthogonal polynomials."""
from sympy.core.symbol import Dummy
from sympy.polys.densearith import (dup_mul, dup_mul_ground,
dup_lshift, dup_sub, dup_add, dup_sub_term, dup_sub_ground, dup_sqr)
from sympy.polys.domains import ZZ, QQ
from sympy.polys.polytools import named_poly
from sympy.utilities import public
def dup_jacobi(n, a, b, K):
"""Low-level implementation of Jacobi polynomials."""
if n < 1:
return [K.one]
m2, m1 = [K.one], [(a+b)/K(2) + K.one, (a-b)/K(2)]
for i in range(2, n+1):
den = K(i)*(a + b + i)*(a + b + K(2)*i - K(2))
f0 = (a + b + K(2)*i - K.one) * (a*a - b*b) / (K(2)*den)
f1 = (a + b + K(2)*i - K.one) * (a + b + K(2)*i - K(2)) * (a + b + K(2)*i) / (K(2)*den)
f2 = (a + i - K.one)*(b + i - K.one)*(a + b + K(2)*i) / den
p0 = dup_mul_ground(m1, f0, K)
p1 = dup_mul_ground(dup_lshift(m1, 1, K), f1, K)
p2 = dup_mul_ground(m2, f2, K)
m2, m1 = m1, dup_sub(dup_add(p0, p1, K), p2, K)
return m1
@public
def jacobi_poly(n, a, b, x=None, polys=False):
r"""Generates the Jacobi polynomial `P_n^{(a,b)}(x)`.
Parameters
==========
n : int
Degree of the polynomial.
a
Lower limit of minimal domain for the list of coefficients.
b
Upper limit of minimal domain for the list of coefficients.
x : optional
polys : bool, optional
If True, return a Poly, otherwise (default) return an expression.
"""
return named_poly(n, dup_jacobi, None, "Jacobi polynomial", (x, a, b), polys)
def dup_gegenbauer(n, a, K):
"""Low-level implementation of Gegenbauer polynomials."""
if n < 1:
return [K.one]
m2, m1 = [K.one], [K(2)*a, K.zero]
for i in range(2, n+1):
p1 = dup_mul_ground(dup_lshift(m1, 1, K), K(2)*(a-K.one)/K(i) + K(2), K)
p2 = dup_mul_ground(m2, K(2)*(a-K.one)/K(i) + K.one, K)
m2, m1 = m1, dup_sub(p1, p2, K)
return m1
def gegenbauer_poly(n, a, x=None, polys=False):
r"""Generates the Gegenbauer polynomial `C_n^{(a)}(x)`.
Parameters
==========
n : int
Degree of the polynomial.
x : optional
a
Decides minimal domain for the list of coefficients.
polys : bool, optional
If True, return a Poly, otherwise (default) return an expression.
"""
return named_poly(n, dup_gegenbauer, None, "Gegenbauer polynomial", (x, a), polys)
def dup_chebyshevt(n, K):
"""Low-level implementation of Chebyshev polynomials of the first kind."""
if n < 1:
return [K.one]
# When n is small, it is faster to directly calculate the recurrence relation.
if n < 64: # The threshold serves as a heuristic
return _dup_chebyshevt_rec(n, K)
return _dup_chebyshevt_prod(n, K)
def _dup_chebyshevt_rec(n, K):
r""" Chebyshev polynomials of the first kind using recurrence.
Explanation
===========
Chebyshev polynomials of the first kind are defined by the recurrence
relation:
.. math::
T_0(x) &= 1\\
T_1(x) &= x\\
T_n(x) &= 2xT_{n-1}(x) - T_{n-2}(x)
This function calculates the Chebyshev polynomial of the first kind using
the above recurrence relation.
Parameters
==========
n : int
n is a nonnegative integer.
K : domain
"""
m2, m1 = [K.one], [K.one, K.zero]
for _ in range(n - 1):
m2, m1 = m1, dup_sub(dup_mul_ground(dup_lshift(m1, 1, K), K(2), K), m2, K)
return m1
def _dup_chebyshevt_prod(n, K):
r""" Chebyshev polynomials of the first kind using recursive products.
Explanation
===========
Computes Chebyshev polynomials of the first kind using
.. math::
T_{2n}(x) &= 2T_n^2(x) - 1\\
T_{2n+1}(x) &= 2T_{n+1}(x)T_n(x) - x
This is faster than ``_dup_chebyshevt_rec`` for large ``n``.
Parameters
==========
n : int
n is a nonnegative integer.
K : domain
"""
m2, m1 = [K.one, K.zero], [K(2), K.zero, -K.one]
for i in bin(n)[3:]:
c = dup_sub_term(dup_mul_ground(dup_mul(m1, m2, K), K(2), K), K.one, 1, K)
if i == '1':
m2, m1 = c, dup_sub_ground(dup_mul_ground(dup_sqr(m1, K), K(2), K), K.one, K)
else:
m2, m1 = dup_sub_ground(dup_mul_ground(dup_sqr(m2, K), K(2), K), K.one, K), c
return m2
def dup_chebyshevu(n, K):
"""Low-level implementation of Chebyshev polynomials of the second kind."""
if n < 1:
return [K.one]
m2, m1 = [K.one], [K(2), K.zero]
for i in range(2, n+1):
m2, m1 = m1, dup_sub(dup_mul_ground(dup_lshift(m1, 1, K), K(2), K), m2, K)
return m1
@public
def chebyshevt_poly(n, x=None, polys=False):
r"""Generates the Chebyshev polynomial of the first kind `T_n(x)`.
Parameters
==========
n : int
Degree of the polynomial.
x : optional
polys : bool, optional
If True, return a Poly, otherwise (default) return an expression.
"""
return named_poly(n, dup_chebyshevt, ZZ,
"Chebyshev polynomial of the first kind", (x,), polys)
@public
def chebyshevu_poly(n, x=None, polys=False):
r"""Generates the Chebyshev polynomial of the second kind `U_n(x)`.
Parameters
==========
n : int
Degree of the polynomial.
x : optional
polys : bool, optional
If True, return a Poly, otherwise (default) return an expression.
"""
return named_poly(n, dup_chebyshevu, ZZ,
"Chebyshev polynomial of the second kind", (x,), polys)
def dup_hermite(n, K):
"""Low-level implementation of Hermite polynomials."""
if n < 1:
return [K.one]
m2, m1 = [K.one], [K(2), K.zero]
for i in range(2, n+1):
a = dup_lshift(m1, 1, K)
b = dup_mul_ground(m2, K(i-1), K)
m2, m1 = m1, dup_mul_ground(dup_sub(a, b, K), K(2), K)
return m1
def dup_hermite_prob(n, K):
"""Low-level implementation of probabilist's Hermite polynomials."""
if n < 1:
return [K.one]
m2, m1 = [K.one], [K.one, K.zero]
for i in range(2, n+1):
a = dup_lshift(m1, 1, K)
b = dup_mul_ground(m2, K(i-1), K)
m2, m1 = m1, dup_sub(a, b, K)
return m1
@public
def hermite_poly(n, x=None, polys=False):
r"""Generates the Hermite polynomial `H_n(x)`.
Parameters
==========
n : int
Degree of the polynomial.
x : optional
polys : bool, optional
If True, return a Poly, otherwise (default) return an expression.
"""
return named_poly(n, dup_hermite, ZZ, "Hermite polynomial", (x,), polys)
@public
def hermite_prob_poly(n, x=None, polys=False):
r"""Generates the probabilist's Hermite polynomial `He_n(x)`.
Parameters
==========
n : int
Degree of the polynomial.
x : optional
polys : bool, optional
If True, return a Poly, otherwise (default) return an expression.
"""
return named_poly(n, dup_hermite_prob, ZZ,
"probabilist's Hermite polynomial", (x,), polys)
def dup_legendre(n, K):
"""Low-level implementation of Legendre polynomials."""
if n < 1:
return [K.one]
m2, m1 = [K.one], [K.one, K.zero]
for i in range(2, n+1):
a = dup_mul_ground(dup_lshift(m1, 1, K), K(2*i-1, i), K)
b = dup_mul_ground(m2, K(i-1, i), K)
m2, m1 = m1, dup_sub(a, b, K)
return m1
@public
def legendre_poly(n, x=None, polys=False):
r"""Generates the Legendre polynomial `P_n(x)`.
Parameters
==========
n : int
Degree of the polynomial.
x : optional
polys : bool, optional
If True, return a Poly, otherwise (default) return an expression.
"""
return named_poly(n, dup_legendre, QQ, "Legendre polynomial", (x,), polys)
def dup_laguerre(n, alpha, K):
"""Low-level implementation of Laguerre polynomials."""
m2, m1 = [K.zero], [K.one]
for i in range(1, n+1):
a = dup_mul(m1, [-K.one/K(i), (alpha-K.one)/K(i) + K(2)], K)
b = dup_mul_ground(m2, (alpha-K.one)/K(i) + K.one, K)
m2, m1 = m1, dup_sub(a, b, K)
return m1
@public
def laguerre_poly(n, x=None, alpha=0, polys=False):
r"""Generates the Laguerre polynomial `L_n^{(\alpha)}(x)`.
Parameters
==========
n : int
Degree of the polynomial.
x : optional
alpha : optional
Decides minimal domain for the list of coefficients.
polys : bool, optional
If True, return a Poly, otherwise (default) return an expression.
"""
return named_poly(n, dup_laguerre, None, "Laguerre polynomial", (x, alpha), polys)
def dup_spherical_bessel_fn(n, K):
"""Low-level implementation of fn(n, x)."""
if n < 1:
return [K.one, K.zero]
m2, m1 = [K.one], [K.one, K.zero]
for i in range(2, n+1):
m2, m1 = m1, dup_sub(dup_mul_ground(dup_lshift(m1, 1, K), K(2*i-1), K), m2, K)
return dup_lshift(m1, 1, K)
def dup_spherical_bessel_fn_minus(n, K):
"""Low-level implementation of fn(-n, x)."""
m2, m1 = [K.one, K.zero], [K.zero]
for i in range(2, n+1):
m2, m1 = m1, dup_sub(dup_mul_ground(dup_lshift(m1, 1, K), K(3-2*i), K), m2, K)
return m1
def spherical_bessel_fn(n, x=None, polys=False):
"""
Coefficients for the spherical Bessel functions.
These are only needed in the jn() function.
The coefficients are calculated from:
fn(0, z) = 1/z
fn(1, z) = 1/z**2
fn(n-1, z) + fn(n+1, z) == (2*n+1)/z * fn(n, z)
Parameters
==========
n : int
Degree of the polynomial.
x : optional
polys : bool, optional
If True, return a Poly, otherwise (default) return an expression.
Examples
========
>>> from sympy.polys.orthopolys import spherical_bessel_fn as fn
>>> from sympy import Symbol
>>> z = Symbol("z")
>>> fn(1, z)
z**(-2)
>>> fn(2, z)
-1/z + 3/z**3
>>> fn(3, z)
-6/z**2 + 15/z**4
>>> fn(4, z)
1/z - 45/z**3 + 105/z**5
"""
if x is None:
x = Dummy("x")
f = dup_spherical_bessel_fn_minus if n < 0 else dup_spherical_bessel_fn
return named_poly(abs(n), f, ZZ, "", (QQ(1)/x,), polys)
PK ]ZZZ��h9 h9 sympy/polys/partfrac.py"""Algorithms for partial fraction decomposition of rational functions. """
from sympy.core import S, Add, sympify, Function, Lambda, Dummy
from sympy.core.traversal import preorder_traversal
from sympy.polys import Poly, RootSum, cancel, factor
from sympy.polys.polyerrors import PolynomialError
from sympy.polys.polyoptions import allowed_flags, set_defaults
from sympy.polys.polytools import parallel_poly_from_expr
from sympy.utilities import numbered_symbols, take, xthreaded, public
@xthreaded
@public
def apart(f, x=None, full=False, **options):
"""
Compute partial fraction decomposition of a rational function.
Given a rational function ``f``, computes the partial fraction
decomposition of ``f``. Two algorithms are available: One is based on the
undertermined coefficients method, the other is Bronstein's full partial
fraction decomposition algorithm.
The undetermined coefficients method (selected by ``full=False``) uses
polynomial factorization (and therefore accepts the same options as
factor) for the denominator. Per default it works over the rational
numbers, therefore decomposition of denominators with non-rational roots
(e.g. irrational, complex roots) is not supported by default (see options
of factor).
Bronstein's algorithm can be selected by using ``full=True`` and allows a
decomposition of denominators with non-rational roots. A human-readable
result can be obtained via ``doit()`` (see examples below).
Examples
========
>>> from sympy.polys.partfrac import apart
>>> from sympy.abc import x, y
By default, using the undetermined coefficients method:
>>> apart(y/(x + 2)/(x + 1), x)
-y/(x + 2) + y/(x + 1)
The undetermined coefficients method does not provide a result when the
denominators roots are not rational:
>>> apart(y/(x**2 + x + 1), x)
y/(x**2 + x + 1)
You can choose Bronstein's algorithm by setting ``full=True``:
>>> apart(y/(x**2 + x + 1), x, full=True)
RootSum(_w**2 + _w + 1, Lambda(_a, (-2*_a*y/3 - y/3)/(-_a + x)))
Calling ``doit()`` yields a human-readable result:
>>> apart(y/(x**2 + x + 1), x, full=True).doit()
(-y/3 - 2*y*(-1/2 - sqrt(3)*I/2)/3)/(x + 1/2 + sqrt(3)*I/2) + (-y/3 -
2*y*(-1/2 + sqrt(3)*I/2)/3)/(x + 1/2 - sqrt(3)*I/2)
See Also
========
apart_list, assemble_partfrac_list
"""
allowed_flags(options, [])
f = sympify(f)
if f.is_Atom:
return f
else:
P, Q = f.as_numer_denom()
_options = options.copy()
options = set_defaults(options, extension=True)
try:
(P, Q), opt = parallel_poly_from_expr((P, Q), x, **options)
except PolynomialError as msg:
if f.is_commutative:
raise PolynomialError(msg)
# non-commutative
if f.is_Mul:
c, nc = f.args_cnc(split_1=False)
nc = f.func(*nc)
if c:
c = apart(f.func._from_args(c), x=x, full=full, **_options)
return c*nc
else:
return nc
elif f.is_Add:
c = []
nc = []
for i in f.args:
if i.is_commutative:
c.append(i)
else:
try:
nc.append(apart(i, x=x, full=full, **_options))
except NotImplementedError:
nc.append(i)
return apart(f.func(*c), x=x, full=full, **_options) + f.func(*nc)
else:
reps = []
pot = preorder_traversal(f)
next(pot)
for e in pot:
try:
reps.append((e, apart(e, x=x, full=full, **_options)))
pot.skip() # this was handled successfully
except NotImplementedError:
pass
return f.xreplace(dict(reps))
if P.is_multivariate:
fc = f.cancel()
if fc != f:
return apart(fc, x=x, full=full, **_options)
raise NotImplementedError(
"multivariate partial fraction decomposition")
common, P, Q = P.cancel(Q)
poly, P = P.div(Q, auto=True)
P, Q = P.rat_clear_denoms(Q)
if Q.degree() <= 1:
partial = P/Q
else:
if not full:
partial = apart_undetermined_coeffs(P, Q)
else:
partial = apart_full_decomposition(P, Q)
terms = S.Zero
for term in Add.make_args(partial):
if term.has(RootSum):
terms += term
else:
terms += factor(term)
return common*(poly.as_expr() + terms)
def apart_undetermined_coeffs(P, Q):
"""Partial fractions via method of undetermined coefficients. """
X = numbered_symbols(cls=Dummy)
partial, symbols = [], []
_, factors = Q.factor_list()
for f, k in factors:
n, q = f.degree(), Q
for i in range(1, k + 1):
coeffs, q = take(X, n), q.quo(f)
partial.append((coeffs, q, f, i))
symbols.extend(coeffs)
dom = Q.get_domain().inject(*symbols)
F = Poly(0, Q.gen, domain=dom)
for i, (coeffs, q, f, k) in enumerate(partial):
h = Poly(coeffs, Q.gen, domain=dom)
partial[i] = (h, f, k)
q = q.set_domain(dom)
F += h*q
system, result = [], S.Zero
for (k,), coeff in F.terms():
system.append(coeff - P.nth(k))
from sympy.solvers import solve
solution = solve(system, symbols)
for h, f, k in partial:
h = h.as_expr().subs(solution)
result += h/f.as_expr()**k
return result
def apart_full_decomposition(P, Q):
"""
Bronstein's full partial fraction decomposition algorithm.
Given a univariate rational function ``f``, performing only GCD
operations over the algebraic closure of the initial ground domain
of definition, compute full partial fraction decomposition with
fractions having linear denominators.
Note that no factorization of the initial denominator of ``f`` is
performed. The final decomposition is formed in terms of a sum of
:class:`RootSum` instances.
References
==========
.. [1] [Bronstein93]_
"""
return assemble_partfrac_list(apart_list(P/Q, P.gens[0]))
@public
def apart_list(f, x=None, dummies=None, **options):
"""
Compute partial fraction decomposition of a rational function
and return the result in structured form.
Given a rational function ``f`` compute the partial fraction decomposition
of ``f``. Only Bronstein's full partial fraction decomposition algorithm
is supported by this method. The return value is highly structured and
perfectly suited for further algorithmic treatment rather than being
human-readable. The function returns a tuple holding three elements:
* The first item is the common coefficient, free of the variable `x` used
for decomposition. (It is an element of the base field `K`.)
* The second item is the polynomial part of the decomposition. This can be
the zero polynomial. (It is an element of `K[x]`.)
* The third part itself is a list of quadruples. Each quadruple
has the following elements in this order:
- The (not necessarily irreducible) polynomial `D` whose roots `w_i` appear
in the linear denominator of a bunch of related fraction terms. (This item
can also be a list of explicit roots. However, at the moment ``apart_list``
never returns a result this way, but the related ``assemble_partfrac_list``
function accepts this format as input.)
- The numerator of the fraction, written as a function of the root `w`
- The linear denominator of the fraction *excluding its power exponent*,
written as a function of the root `w`.
- The power to which the denominator has to be raised.
On can always rebuild a plain expression by using the function ``assemble_partfrac_list``.
Examples
========
A first example:
>>> from sympy.polys.partfrac import apart_list, assemble_partfrac_list
>>> from sympy.abc import x, t
>>> f = (2*x**3 - 2*x) / (x**2 - 2*x + 1)
>>> pfd = apart_list(f)
>>> pfd
(1,
Poly(2*x + 4, x, domain='ZZ'),
[(Poly(_w - 1, _w, domain='ZZ'), Lambda(_a, 4), Lambda(_a, -_a + x), 1)])
>>> assemble_partfrac_list(pfd)
2*x + 4 + 4/(x - 1)
Second example:
>>> f = (-2*x - 2*x**2) / (3*x**2 - 6*x)
>>> pfd = apart_list(f)
>>> pfd
(-1,
Poly(2/3, x, domain='QQ'),
[(Poly(_w - 2, _w, domain='ZZ'), Lambda(_a, 2), Lambda(_a, -_a + x), 1)])
>>> assemble_partfrac_list(pfd)
-2/3 - 2/(x - 2)
Another example, showing symbolic parameters:
>>> pfd = apart_list(t/(x**2 + x + t), x)
>>> pfd
(1,
Poly(0, x, domain='ZZ[t]'),
[(Poly(_w**2 + _w + t, _w, domain='ZZ[t]'),
Lambda(_a, -2*_a*t/(4*t - 1) - t/(4*t - 1)),
Lambda(_a, -_a + x),
1)])
>>> assemble_partfrac_list(pfd)
RootSum(_w**2 + _w + t, Lambda(_a, (-2*_a*t/(4*t - 1) - t/(4*t - 1))/(-_a + x)))
This example is taken from Bronstein's original paper:
>>> f = 36 / (x**5 - 2*x**4 - 2*x**3 + 4*x**2 + x - 2)
>>> pfd = apart_list(f)
>>> pfd
(1,
Poly(0, x, domain='ZZ'),
[(Poly(_w - 2, _w, domain='ZZ'), Lambda(_a, 4), Lambda(_a, -_a + x), 1),
(Poly(_w**2 - 1, _w, domain='ZZ'), Lambda(_a, -3*_a - 6), Lambda(_a, -_a + x), 2),
(Poly(_w + 1, _w, domain='ZZ'), Lambda(_a, -4), Lambda(_a, -_a + x), 1)])
>>> assemble_partfrac_list(pfd)
-4/(x + 1) - 3/(x + 1)**2 - 9/(x - 1)**2 + 4/(x - 2)
See also
========
apart, assemble_partfrac_list
References
==========
.. [1] [Bronstein93]_
"""
allowed_flags(options, [])
f = sympify(f)
if f.is_Atom:
return f
else:
P, Q = f.as_numer_denom()
options = set_defaults(options, extension=True)
(P, Q), opt = parallel_poly_from_expr((P, Q), x, **options)
if P.is_multivariate:
raise NotImplementedError(
"multivariate partial fraction decomposition")
common, P, Q = P.cancel(Q)
poly, P = P.div(Q, auto=True)
P, Q = P.rat_clear_denoms(Q)
polypart = poly
if dummies is None:
def dummies(name):
d = Dummy(name)
while True:
yield d
dummies = dummies("w")
rationalpart = apart_list_full_decomposition(P, Q, dummies)
return (common, polypart, rationalpart)
def apart_list_full_decomposition(P, Q, dummygen):
"""
Bronstein's full partial fraction decomposition algorithm.
Given a univariate rational function ``f``, performing only GCD
operations over the algebraic closure of the initial ground domain
of definition, compute full partial fraction decomposition with
fractions having linear denominators.
Note that no factorization of the initial denominator of ``f`` is
performed. The final decomposition is formed in terms of a sum of
:class:`RootSum` instances.
References
==========
.. [1] [Bronstein93]_
"""
P_orig, Q_orig, x, U = P, Q, P.gen, []
u = Function('u')(x)
a = Dummy('a')
partial = []
for d, n in Q.sqf_list_include(all=True):
b = d.as_expr()
U += [ u.diff(x, n - 1) ]
h = cancel(P_orig/Q_orig.quo(d**n)) / u**n
H, subs = [h], []
for j in range(1, n):
H += [ H[-1].diff(x) / j ]
for j in range(1, n + 1):
subs += [ (U[j - 1], b.diff(x, j) / j) ]
for j in range(0, n):
P, Q = cancel(H[j]).as_numer_denom()
for i in range(0, j + 1):
P = P.subs(*subs[j - i])
Q = Q.subs(*subs[0])
P = Poly(P, x)
Q = Poly(Q, x)
G = P.gcd(d)
D = d.quo(G)
B, g = Q.half_gcdex(D)
b = (P * B.quo(g)).rem(D)
Dw = D.subs(x, next(dummygen))
numer = Lambda(a, b.as_expr().subs(x, a))
denom = Lambda(a, (x - a))
exponent = n-j
partial.append((Dw, numer, denom, exponent))
return partial
@public
def assemble_partfrac_list(partial_list):
r"""Reassemble a full partial fraction decomposition
from a structured result obtained by the function ``apart_list``.
Examples
========
This example is taken from Bronstein's original paper:
>>> from sympy.polys.partfrac import apart_list, assemble_partfrac_list
>>> from sympy.abc import x
>>> f = 36 / (x**5 - 2*x**4 - 2*x**3 + 4*x**2 + x - 2)
>>> pfd = apart_list(f)
>>> pfd
(1,
Poly(0, x, domain='ZZ'),
[(Poly(_w - 2, _w, domain='ZZ'), Lambda(_a, 4), Lambda(_a, -_a + x), 1),
(Poly(_w**2 - 1, _w, domain='ZZ'), Lambda(_a, -3*_a - 6), Lambda(_a, -_a + x), 2),
(Poly(_w + 1, _w, domain='ZZ'), Lambda(_a, -4), Lambda(_a, -_a + x), 1)])
>>> assemble_partfrac_list(pfd)
-4/(x + 1) - 3/(x + 1)**2 - 9/(x - 1)**2 + 4/(x - 2)
If we happen to know some roots we can provide them easily inside the structure:
>>> pfd = apart_list(2/(x**2-2))
>>> pfd
(1,
Poly(0, x, domain='ZZ'),
[(Poly(_w**2 - 2, _w, domain='ZZ'),
Lambda(_a, _a/2),
Lambda(_a, -_a + x),
1)])
>>> pfda = assemble_partfrac_list(pfd)
>>> pfda
RootSum(_w**2 - 2, Lambda(_a, _a/(-_a + x)))/2
>>> pfda.doit()
-sqrt(2)/(2*(x + sqrt(2))) + sqrt(2)/(2*(x - sqrt(2)))
>>> from sympy import Dummy, Poly, Lambda, sqrt
>>> a = Dummy("a")
>>> pfd = (1, Poly(0, x, domain='ZZ'), [([sqrt(2),-sqrt(2)], Lambda(a, a/2), Lambda(a, -a + x), 1)])
>>> assemble_partfrac_list(pfd)
-sqrt(2)/(2*(x + sqrt(2))) + sqrt(2)/(2*(x - sqrt(2)))
See Also
========
apart, apart_list
"""
# Common factor
common = partial_list[0]
# Polynomial part
polypart = partial_list[1]
pfd = polypart.as_expr()
# Rational parts
for r, nf, df, ex in partial_list[2]:
if isinstance(r, Poly):
# Assemble in case the roots are given implicitly by a polynomials
an, nu = nf.variables, nf.expr
ad, de = df.variables, df.expr
# Hack to make dummies equal because Lambda created new Dummies
de = de.subs(ad[0], an[0])
func = Lambda(tuple(an), nu/de**ex)
pfd += RootSum(r, func, auto=False, quadratic=False)
else:
# Assemble in case the roots are given explicitly by a list of algebraic numbers
for root in r:
pfd += nf(root)/df(root)**ex
return common*pfd
PK ]ZZZ�&p�o �o sympy/polys/polyclasses.py"""OO layer for several polynomial representations. """
from __future__ import annotations
from sympy.external.gmpy import GROUND_TYPES
from sympy.utilities.exceptions import sympy_deprecation_warning
from sympy.core.numbers import oo
from sympy.core.sympify import CantSympify
from sympy.polys.polyutils import PicklableWithSlots, _sort_factors
from sympy.polys.domains import Domain, ZZ, QQ
from sympy.polys.polyerrors import (
CoercionFailed,
ExactQuotientFailed,
DomainError,
NotInvertible,
)
from sympy.polys.densebasic import (
ninf,
dmp_validate,
dup_normal, dmp_normal,
dup_convert, dmp_convert,
dmp_from_sympy,
dup_strip,
dmp_degree_in,
dmp_degree_list,
dmp_negative_p,
dmp_ground_LC,
dmp_ground_TC,
dmp_ground_nth,
dmp_one, dmp_ground,
dmp_zero, dmp_zero_p, dmp_one_p, dmp_ground_p,
dup_from_dict, dmp_from_dict,
dmp_to_dict,
dmp_deflate,
dmp_inject, dmp_eject,
dmp_terms_gcd,
dmp_list_terms, dmp_exclude,
dup_slice, dmp_slice_in, dmp_permute,
dmp_to_tuple,)
from sympy.polys.densearith import (
dmp_add_ground,
dmp_sub_ground,
dmp_mul_ground,
dmp_quo_ground,
dmp_exquo_ground,
dmp_abs,
dmp_neg,
dmp_add,
dmp_sub,
dmp_mul,
dmp_sqr,
dmp_pow,
dmp_pdiv,
dmp_prem,
dmp_pquo,
dmp_pexquo,
dmp_div,
dmp_rem,
dmp_quo,
dmp_exquo,
dmp_add_mul, dmp_sub_mul,
dmp_max_norm,
dmp_l1_norm,
dmp_l2_norm_squared)
from sympy.polys.densetools import (
dmp_clear_denoms,
dmp_integrate_in,
dmp_diff_in,
dmp_eval_in,
dup_revert,
dmp_ground_trunc,
dmp_ground_content,
dmp_ground_primitive,
dmp_ground_monic,
dmp_compose,
dup_decompose,
dup_shift,
dmp_shift,
dup_transform,
dmp_lift)
from sympy.polys.euclidtools import (
dup_half_gcdex, dup_gcdex, dup_invert,
dmp_subresultants,
dmp_resultant,
dmp_discriminant,
dmp_inner_gcd,
dmp_gcd,
dmp_lcm,
dmp_cancel)
from sympy.polys.sqfreetools import (
dup_gff_list,
dmp_norm,
dmp_sqf_p,
dmp_sqf_norm,
dmp_sqf_part,
dmp_sqf_list, dmp_sqf_list_include)
from sympy.polys.factortools import (
dup_cyclotomic_p, dmp_irreducible_p,
dmp_factor_list, dmp_factor_list_include)
from sympy.polys.rootisolation import (
dup_isolate_real_roots_sqf,
dup_isolate_real_roots,
dup_isolate_all_roots_sqf,
dup_isolate_all_roots,
dup_refine_real_root,
dup_count_real_roots,
dup_count_complex_roots,
dup_sturm,
dup_cauchy_upper_bound,
dup_cauchy_lower_bound,
dup_mignotte_sep_bound_squared)
from sympy.polys.polyerrors import (
UnificationFailed,
PolynomialError)
_flint_domains: tuple[Domain, ...]
if GROUND_TYPES == 'flint':
import flint
_flint_domains = (ZZ, QQ)
else:
flint = None
_flint_domains = ()
class DMP(CantSympify):
"""Dense Multivariate Polynomials over `K`. """
__slots__ = ()
def __new__(cls, rep, dom, lev=None):
if lev is None:
rep, lev = dmp_validate(rep)
elif not isinstance(rep, list):
raise CoercionFailed("expected list, got %s" % type(rep))
return cls.new(rep, dom, lev)
@classmethod
def new(cls, rep, dom, lev):
# It would be too slow to call _validate_args always at runtime.
# Ideally this checking would be handled by a static type checker.
#
#cls._validate_args(rep, dom, lev)
if flint is not None:
if lev == 0 and dom in _flint_domains:
return DUP_Flint._new(rep, dom, lev)
return DMP_Python._new(rep, dom, lev)
@property
def rep(f):
"""Get the representation of ``f``. """
sympy_deprecation_warning("""
Accessing the ``DMP.rep`` attribute is deprecated. The internal
representation of ``DMP`` instances can now be ``DUP_Flint`` when the
ground types are ``flint``. In this case the ``DMP`` instance does not
have a ``rep`` attribute. Use ``DMP.to_list()`` instead. Using
``DMP.to_list()`` also works in previous versions of SymPy.
""",
deprecated_since_version="1.13",
active_deprecations_target="dmp-rep",
)
return f.to_list()
def to_best(f):
"""Convert to DUP_Flint if possible.
This method should be used when the domain or level is changed and it
potentially becomes possible to convert from DMP_Python to DUP_Flint.
"""
if flint is not None:
if isinstance(f, DMP_Python) and f.lev == 0 and f.dom in _flint_domains:
return DUP_Flint.new(f._rep, f.dom, f.lev)
return f
@classmethod
def _validate_args(cls, rep, dom, lev):
assert isinstance(dom, Domain)
assert isinstance(lev, int) and lev >= 0
def validate_rep(rep, lev):
assert isinstance(rep, list)
if lev == 0:
assert all(dom.of_type(c) for c in rep)
else:
for r in rep:
validate_rep(r, lev - 1)
validate_rep(rep, lev)
@classmethod
def from_dict(cls, rep, lev, dom):
rep = dmp_from_dict(rep, lev, dom)
return cls.new(rep, dom, lev)
@classmethod
def from_list(cls, rep, lev, dom):
"""Create an instance of ``cls`` given a list of native coefficients. """
return cls.new(dmp_convert(rep, lev, None, dom), dom, lev)
@classmethod
def from_sympy_list(cls, rep, lev, dom):
"""Create an instance of ``cls`` given a list of SymPy coefficients. """
return cls.new(dmp_from_sympy(rep, lev, dom), dom, lev)
@classmethod
def from_monoms_coeffs(cls, monoms, coeffs, lev, dom):
return cls(dict(list(zip(monoms, coeffs))), dom, lev)
def convert(f, dom):
"""Convert ``f`` to a ``DMP`` over the new domain. """
if f.dom == dom:
return f
elif f.lev or flint is None:
return f._convert(dom)
elif isinstance(f, DUP_Flint):
if dom in _flint_domains:
return f._convert(dom)
else:
return f.to_DMP_Python()._convert(dom)
elif isinstance(f, DMP_Python):
if dom in _flint_domains:
return f._convert(dom).to_DUP_Flint()
else:
return f._convert(dom)
else:
raise RuntimeError("unreachable code")
def _convert(f, dom):
raise NotImplementedError
@classmethod
def zero(cls, lev, dom):
return DMP(dmp_zero(lev), dom, lev)
@classmethod
def one(cls, lev, dom):
return DMP(dmp_one(lev, dom), dom, lev)
def _one(f):
raise NotImplementedError
def __repr__(f):
return "%s(%s, %s)" % (f.__class__.__name__, f.to_list(), f.dom)
def __hash__(f):
return hash((f.__class__.__name__, f.to_tuple(), f.lev, f.dom))
def __getnewargs__(self):
return self.to_list(), self.dom, self.lev
def ground_new(f, coeff):
"""Construct a new ground instance of ``f``. """
raise NotImplementedError
def unify_DMP(f, g):
"""Unify and return ``DMP`` instances of ``f`` and ``g``. """
if not isinstance(g, DMP) or f.lev != g.lev:
raise UnificationFailed("Cannot unify %s with %s" % (f, g))
if f.dom != g.dom:
dom = f.dom.unify(g.dom)
f = f.convert(dom)
g = g.convert(dom)
return f, g
def to_dict(f, zero=False):
"""Convert ``f`` to a dict representation with native coefficients. """
return dmp_to_dict(f.to_list(), f.lev, f.dom, zero=zero)
def to_sympy_dict(f, zero=False):
"""Convert ``f`` to a dict representation with SymPy coefficients. """
rep = f.to_dict(zero=zero)
for k, v in rep.items():
rep[k] = f.dom.to_sympy(v)
return rep
def to_sympy_list(f):
"""Convert ``f`` to a list representation with SymPy coefficients. """
def sympify_nested_list(rep):
out = []
for val in rep:
if isinstance(val, list):
out.append(sympify_nested_list(val))
else:
out.append(f.dom.to_sympy(val))
return out
return sympify_nested_list(f.to_list())
def to_list(f):
"""Convert ``f`` to a list representation with native coefficients. """
raise NotImplementedError
def to_tuple(f):
"""
Convert ``f`` to a tuple representation with native coefficients.
This is needed for hashing.
"""
raise NotImplementedError
def to_ring(f):
"""Make the ground domain a ring. """
return f.convert(f.dom.get_ring())
def to_field(f):
"""Make the ground domain a field. """
return f.convert(f.dom.get_field())
def to_exact(f):
"""Make the ground domain exact. """
return f.convert(f.dom.get_exact())
def slice(f, m, n, j=0):
"""Take a continuous subsequence of terms of ``f``. """
if not f.lev and not j:
return f._slice(m, n)
else:
return f._slice_lev(m, n, j)
def _slice(f, m, n):
raise NotImplementedError
def _slice_lev(f, m, n, j):
raise NotImplementedError
def coeffs(f, order=None):
"""Returns all non-zero coefficients from ``f`` in lex order. """
return [ c for _, c in f.terms(order=order) ]
def monoms(f, order=None):
"""Returns all non-zero monomials from ``f`` in lex order. """
return [ m for m, _ in f.terms(order=order) ]
def terms(f, order=None):
"""Returns all non-zero terms from ``f`` in lex order. """
if f.is_zero:
zero_monom = (0,)*(f.lev + 1)
return [(zero_monom, f.dom.zero)]
else:
return f._terms(order=order)
def _terms(f, order=None):
raise NotImplementedError
def all_coeffs(f):
"""Returns all coefficients from ``f``. """
if f.lev:
raise PolynomialError('multivariate polynomials not supported')
if not f:
return [f.dom.zero]
else:
return list(f.to_list())
def all_monoms(f):
"""Returns all monomials from ``f``. """
if f.lev:
raise PolynomialError('multivariate polynomials not supported')
n = f.degree()
if n < 0:
return [(0,)]
else:
return [ (n - i,) for i, c in enumerate(f.to_list()) ]
def all_terms(f):
"""Returns all terms from a ``f``. """
if f.lev:
raise PolynomialError('multivariate polynomials not supported')
n = f.degree()
if n < 0:
return [((0,), f.dom.zero)]
else:
return [ ((n - i,), c) for i, c in enumerate(f.to_list()) ]
def lift(f):
"""Convert algebraic coefficients to rationals. """
return f._lift().to_best()
def _lift(f):
raise NotImplementedError
def deflate(f):
"""Reduce degree of `f` by mapping `x_i^m` to `y_i`. """
raise NotImplementedError
def inject(f, front=False):
"""Inject ground domain generators into ``f``. """
raise NotImplementedError
def eject(f, dom, front=False):
"""Eject selected generators into the ground domain. """
raise NotImplementedError
def exclude(f):
r"""
Remove useless generators from ``f``.
Returns the removed generators and the new excluded ``f``.
Examples
========
>>> from sympy.polys.polyclasses import DMP
>>> from sympy.polys.domains import ZZ
>>> DMP([[[ZZ(1)]], [[ZZ(1)], [ZZ(2)]]], ZZ).exclude()
([2], DMP_Python([[1], [1, 2]], ZZ))
"""
J, F = f._exclude()
return J, F.to_best()
def _exclude(f):
raise NotImplementedError
def permute(f, P):
r"""
Returns a polynomial in `K[x_{P(1)}, ..., x_{P(n)}]`.
Examples
========
>>> from sympy.polys.polyclasses import DMP
>>> from sympy.polys.domains import ZZ
>>> DMP([[[ZZ(2)], [ZZ(1), ZZ(0)]], [[]]], ZZ).permute([1, 0, 2])
DMP_Python([[[2], []], [[1, 0], []]], ZZ)
>>> DMP([[[ZZ(2)], [ZZ(1), ZZ(0)]], [[]]], ZZ).permute([1, 2, 0])
DMP_Python([[[1], []], [[2, 0], []]], ZZ)
"""
return f._permute(P)
def _permute(f, P):
raise NotImplementedError
def terms_gcd(f):
"""Remove GCD of terms from the polynomial ``f``. """
raise NotImplementedError
def abs(f):
"""Make all coefficients in ``f`` positive. """
raise NotImplementedError
def neg(f):
"""Negate all coefficients in ``f``. """
raise NotImplementedError
def add_ground(f, c):
"""Add an element of the ground domain to ``f``. """
return f._add_ground(f.dom.convert(c))
def sub_ground(f, c):
"""Subtract an element of the ground domain from ``f``. """
return f._sub_ground(f.dom.convert(c))
def mul_ground(f, c):
"""Multiply ``f`` by a an element of the ground domain. """
return f._mul_ground(f.dom.convert(c))
def quo_ground(f, c):
"""Quotient of ``f`` by a an element of the ground domain. """
return f._quo_ground(f.dom.convert(c))
def exquo_ground(f, c):
"""Exact quotient of ``f`` by a an element of the ground domain. """
return f._exquo_ground(f.dom.convert(c))
def add(f, g):
"""Add two multivariate polynomials ``f`` and ``g``. """
F, G = f.unify_DMP(g)
return F._add(G)
def sub(f, g):
"""Subtract two multivariate polynomials ``f`` and ``g``. """
F, G = f.unify_DMP(g)
return F._sub(G)
def mul(f, g):
"""Multiply two multivariate polynomials ``f`` and ``g``. """
F, G = f.unify_DMP(g)
return F._mul(G)
def sqr(f):
"""Square a multivariate polynomial ``f``. """
return f._sqr()
def pow(f, n):
"""Raise ``f`` to a non-negative power ``n``. """
if not isinstance(n, int):
raise TypeError("``int`` expected, got %s" % type(n))
return f._pow(n)
def pdiv(f, g):
"""Polynomial pseudo-division of ``f`` and ``g``. """
F, G = f.unify_DMP(g)
return F._pdiv(G)
def prem(f, g):
"""Polynomial pseudo-remainder of ``f`` and ``g``. """
F, G = f.unify_DMP(g)
return F._prem(G)
def pquo(f, g):
"""Polynomial pseudo-quotient of ``f`` and ``g``. """
F, G = f.unify_DMP(g)
return F._pquo(G)
def pexquo(f, g):
"""Polynomial exact pseudo-quotient of ``f`` and ``g``. """
F, G = f.unify_DMP(g)
return F._pexquo(G)
def div(f, g):
"""Polynomial division with remainder of ``f`` and ``g``. """
F, G = f.unify_DMP(g)
return F._div(G)
def rem(f, g):
"""Computes polynomial remainder of ``f`` and ``g``. """
F, G = f.unify_DMP(g)
return F._rem(G)
def quo(f, g):
"""Computes polynomial quotient of ``f`` and ``g``. """
F, G = f.unify_DMP(g)
return F._quo(G)
def exquo(f, g):
"""Computes polynomial exact quotient of ``f`` and ``g``. """
F, G = f.unify_DMP(g)
return F._exquo(G)
def _add_ground(f, c):
raise NotImplementedError
def _sub_ground(f, c):
raise NotImplementedError
def _mul_ground(f, c):
raise NotImplementedError
def _quo_ground(f, c):
raise NotImplementedError
def _exquo_ground(f, c):
raise NotImplementedError
def _add(f, g):
raise NotImplementedError
def _sub(f, g):
raise NotImplementedError
def _mul(f, g):
raise NotImplementedError
def _sqr(f):
raise NotImplementedError
def _pow(f, n):
raise NotImplementedError
def _pdiv(f, g):
raise NotImplementedError
def _prem(f, g):
raise NotImplementedError
def _pquo(f, g):
raise NotImplementedError
def _pexquo(f, g):
raise NotImplementedError
def _div(f, g):
raise NotImplementedError
def _rem(f, g):
raise NotImplementedError
def _quo(f, g):
raise NotImplementedError
def _exquo(f, g):
raise NotImplementedError
def degree(f, j=0):
"""Returns the leading degree of ``f`` in ``x_j``. """
if not isinstance(j, int):
raise TypeError("``int`` expected, got %s" % type(j))
return f._degree(j)
def _degree(f, j):
raise NotImplementedError
def degree_list(f):
"""Returns a list of degrees of ``f``. """
raise NotImplementedError
def total_degree(f):
"""Returns the total degree of ``f``. """
raise NotImplementedError
def homogenize(f, s):
"""Return homogeneous polynomial of ``f``"""
td = f.total_degree()
result = {}
new_symbol = (s == len(f.terms()[0][0]))
for term in f.terms():
d = sum(term[0])
if d < td:
i = td - d
else:
i = 0
if new_symbol:
result[term[0] + (i,)] = term[1]
else:
l = list(term[0])
l[s] += i
result[tuple(l)] = term[1]
return DMP.from_dict(result, f.lev + int(new_symbol), f.dom)
def homogeneous_order(f):
"""Returns the homogeneous order of ``f``. """
if f.is_zero:
return -oo
monoms = f.monoms()
tdeg = sum(monoms[0])
for monom in monoms:
_tdeg = sum(monom)
if _tdeg != tdeg:
return None
return tdeg
def LC(f):
"""Returns the leading coefficient of ``f``. """
raise NotImplementedError
def TC(f):
"""Returns the trailing coefficient of ``f``. """
raise NotImplementedError
def nth(f, *N):
"""Returns the ``n``-th coefficient of ``f``. """
if all(isinstance(n, int) for n in N):
return f._nth(N)
else:
raise TypeError("a sequence of integers expected")
def _nth(f, N):
raise NotImplementedError
def max_norm(f):
"""Returns maximum norm of ``f``. """
raise NotImplementedError
def l1_norm(f):
"""Returns l1 norm of ``f``. """
raise NotImplementedError
def l2_norm_squared(f):
"""Return squared l2 norm of ``f``. """
raise NotImplementedError
def clear_denoms(f):
"""Clear denominators, but keep the ground domain. """
raise NotImplementedError
def integrate(f, m=1, j=0):
"""Computes the ``m``-th order indefinite integral of ``f`` in ``x_j``. """
if not isinstance(m, int):
raise TypeError("``int`` expected, got %s" % type(m))
if not isinstance(j, int):
raise TypeError("``int`` expected, got %s" % type(j))
return f._integrate(m, j)
def _integrate(f, m, j):
raise NotImplementedError
def diff(f, m=1, j=0):
"""Computes the ``m``-th order derivative of ``f`` in ``x_j``. """
if not isinstance(m, int):
raise TypeError("``int`` expected, got %s" % type(m))
if not isinstance(j, int):
raise TypeError("``int`` expected, got %s" % type(j))
return f._diff(m, j)
def _diff(f, m, j):
raise NotImplementedError
def eval(f, a, j=0):
"""Evaluates ``f`` at the given point ``a`` in ``x_j``. """
if not isinstance(j, int):
raise TypeError("``int`` expected, got %s" % type(j))
elif not (0 <= j <= f.lev):
raise ValueError("invalid variable index %s" % j)
if f.lev:
return f._eval_lev(a, j)
else:
return f._eval(a)
def _eval(f, a):
raise NotImplementedError
def _eval_lev(f, a, j):
raise NotImplementedError
def half_gcdex(f, g):
"""Half extended Euclidean algorithm, if univariate. """
F, G = f.unify_DMP(g)
if F.lev:
raise ValueError('univariate polynomial expected')
return F._half_gcdex(G)
def _half_gcdex(f, g):
raise NotImplementedError
def gcdex(f, g):
"""Extended Euclidean algorithm, if univariate. """
F, G = f.unify_DMP(g)
if F.lev:
raise ValueError('univariate polynomial expected')
if not F.dom.is_Field:
raise DomainError('ground domain must be a field')
return F._gcdex(G)
def _gcdex(f, g):
raise NotImplementedError
def invert(f, g):
"""Invert ``f`` modulo ``g``, if possible. """
F, G = f.unify_DMP(g)
if F.lev:
raise ValueError('univariate polynomial expected')
return F._invert(G)
def _invert(f, g):
raise NotImplementedError
def revert(f, n):
"""Compute ``f**(-1)`` mod ``x**n``. """
if f.lev:
raise ValueError('univariate polynomial expected')
return f._revert(n)
def _revert(f, n):
raise NotImplementedError
def subresultants(f, g):
"""Computes subresultant PRS sequence of ``f`` and ``g``. """
F, G = f.unify_DMP(g)
return F._subresultants(G)
def _subresultants(f, g):
raise NotImplementedError
def resultant(f, g, includePRS=False):
"""Computes resultant of ``f`` and ``g`` via PRS. """
F, G = f.unify_DMP(g)
if includePRS:
return F._resultant_includePRS(G)
else:
return F._resultant(G)
def _resultant(f, g, includePRS=False):
raise NotImplementedError
def discriminant(f):
"""Computes discriminant of ``f``. """
raise NotImplementedError
def cofactors(f, g):
"""Returns GCD of ``f`` and ``g`` and their cofactors. """
F, G = f.unify_DMP(g)
return F._cofactors(G)
def _cofactors(f, g):
raise NotImplementedError
def gcd(f, g):
"""Returns polynomial GCD of ``f`` and ``g``. """
F, G = f.unify_DMP(g)
return F._gcd(G)
def _gcd(f, g):
raise NotImplementedError
def lcm(f, g):
"""Returns polynomial LCM of ``f`` and ``g``. """
F, G = f.unify_DMP(g)
return F._lcm(G)
def _lcm(f, g):
raise NotImplementedError
def cancel(f, g, include=True):
"""Cancel common factors in a rational function ``f/g``. """
F, G = f.unify_DMP(g)
if include:
return F._cancel_include(G)
else:
return F._cancel(G)
def _cancel(f, g):
raise NotImplementedError
def _cancel_include(f, g):
raise NotImplementedError
def trunc(f, p):
"""Reduce ``f`` modulo a constant ``p``. """
return f._trunc(f.dom.convert(p))
def _trunc(f, p):
raise NotImplementedError
def monic(f):
"""Divides all coefficients by ``LC(f)``. """
raise NotImplementedError
def content(f):
"""Returns GCD of polynomial coefficients. """
raise NotImplementedError
def primitive(f):
"""Returns content and a primitive form of ``f``. """
raise NotImplementedError
def compose(f, g):
"""Computes functional composition of ``f`` and ``g``. """
F, G = f.unify_DMP(g)
return F._compose(G)
def _compose(f, g):
raise NotImplementedError
def decompose(f):
"""Computes functional decomposition of ``f``. """
if f.lev:
raise ValueError('univariate polynomial expected')
return f._decompose()
def _decompose(f):
raise NotImplementedError
def shift(f, a):
"""Efficiently compute Taylor shift ``f(x + a)``. """
if f.lev:
raise ValueError('univariate polynomial expected')
return f._shift(f.dom.convert(a))
def shift_list(f, a):
"""Efficiently compute Taylor shift ``f(X + A)``. """
a = [f.dom.convert(ai) for ai in a]
return f._shift_list(a)
def _shift(f, a):
raise NotImplementedError
def transform(f, p, q):
"""Evaluate functional transformation ``q**n * f(p/q)``."""
if f.lev:
raise ValueError('univariate polynomial expected')
P, Q = p.unify_DMP(q)
F, P = f.unify_DMP(P)
F, Q = F.unify_DMP(Q)
return F._transform(P, Q)
def _transform(f, p, q):
raise NotImplementedError
def sturm(f):
"""Computes the Sturm sequence of ``f``. """
if f.lev:
raise ValueError('univariate polynomial expected')
return f._sturm()
def _sturm(f):
raise NotImplementedError
def cauchy_upper_bound(f):
"""Computes the Cauchy upper bound on the roots of ``f``. """
if f.lev:
raise ValueError('univariate polynomial expected')
return f._cauchy_upper_bound()
def _cauchy_upper_bound(f):
raise NotImplementedError
def cauchy_lower_bound(f):
"""Computes the Cauchy lower bound on the nonzero roots of ``f``. """
if f.lev:
raise ValueError('univariate polynomial expected')
return f._cauchy_lower_bound()
def _cauchy_lower_bound(f):
raise NotImplementedError
def mignotte_sep_bound_squared(f):
"""Computes the squared Mignotte bound on root separations of ``f``. """
if f.lev:
raise ValueError('univariate polynomial expected')
return f._mignotte_sep_bound_squared()
def _mignotte_sep_bound_squared(f):
raise NotImplementedError
def gff_list(f):
"""Computes greatest factorial factorization of ``f``. """
if f.lev:
raise ValueError('univariate polynomial expected')
return f._gff_list()
def _gff_list(f):
raise NotImplementedError
def norm(f):
"""Computes ``Norm(f)``."""
raise NotImplementedError
def sqf_norm(f):
"""Computes square-free norm of ``f``. """
raise NotImplementedError
def sqf_part(f):
"""Computes square-free part of ``f``. """
raise NotImplementedError
def sqf_list(f, all=False):
"""Returns a list of square-free factors of ``f``. """
raise NotImplementedError
def sqf_list_include(f, all=False):
"""Returns a list of square-free factors of ``f``. """
raise NotImplementedError
def factor_list(f):
"""Returns a list of irreducible factors of ``f``. """
raise NotImplementedError
def factor_list_include(f):
"""Returns a list of irreducible factors of ``f``. """
raise NotImplementedError
def intervals(f, all=False, eps=None, inf=None, sup=None, fast=False, sqf=False):
"""Compute isolating intervals for roots of ``f``. """
if f.lev:
raise PolynomialError("Cannot isolate roots of a multivariate polynomial")
if all and sqf:
return f._isolate_all_roots_sqf(eps=eps, inf=inf, sup=sup, fast=fast)
elif all and not sqf:
return f._isolate_all_roots(eps=eps, inf=inf, sup=sup, fast=fast)
elif not all and sqf:
return f._isolate_real_roots_sqf(eps=eps, inf=inf, sup=sup, fast=fast)
else:
return f._isolate_real_roots(eps=eps, inf=inf, sup=sup, fast=fast)
def _isolate_all_roots(f, eps, inf, sup, fast):
raise NotImplementedError
def _isolate_all_roots_sqf(f, eps, inf, sup, fast):
raise NotImplementedError
def _isolate_real_roots(f, eps, inf, sup, fast):
raise NotImplementedError
def _isolate_real_roots_sqf(f, eps, inf, sup, fast):
raise NotImplementedError
def refine_root(f, s, t, eps=None, steps=None, fast=False):
"""
Refine an isolating interval to the given precision.
``eps`` should be a rational number.
"""
if f.lev:
raise PolynomialError(
"Cannot refine a root of a multivariate polynomial")
return f._refine_real_root(s, t, eps=eps, steps=steps, fast=fast)
def _refine_real_root(f, s, t, eps, steps, fast):
raise NotImplementedError
def count_real_roots(f, inf=None, sup=None):
"""Return the number of real roots of ``f`` in ``[inf, sup]``. """
raise NotImplementedError
def count_complex_roots(f, inf=None, sup=None):
"""Return the number of complex roots of ``f`` in ``[inf, sup]``. """
raise NotImplementedError
@property
def is_zero(f):
"""Returns ``True`` if ``f`` is a zero polynomial. """
raise NotImplementedError
@property
def is_one(f):
"""Returns ``True`` if ``f`` is a unit polynomial. """
raise NotImplementedError
@property
def is_ground(f):
"""Returns ``True`` if ``f`` is an element of the ground domain. """
raise NotImplementedError
@property
def is_sqf(f):
"""Returns ``True`` if ``f`` is a square-free polynomial. """
raise NotImplementedError
@property
def is_monic(f):
"""Returns ``True`` if the leading coefficient of ``f`` is one. """
raise NotImplementedError
@property
def is_primitive(f):
"""Returns ``True`` if the GCD of the coefficients of ``f`` is one. """
raise NotImplementedError
@property
def is_linear(f):
"""Returns ``True`` if ``f`` is linear in all its variables. """
raise NotImplementedError
@property
def is_quadratic(f):
"""Returns ``True`` if ``f`` is quadratic in all its variables. """
raise NotImplementedError
@property
def is_monomial(f):
"""Returns ``True`` if ``f`` is zero or has only one term. """
raise NotImplementedError
@property
def is_homogeneous(f):
"""Returns ``True`` if ``f`` is a homogeneous polynomial. """
raise NotImplementedError
@property
def is_irreducible(f):
"""Returns ``True`` if ``f`` has no factors over its domain. """
raise NotImplementedError
@property
def is_cyclotomic(f):
"""Returns ``True`` if ``f`` is a cyclotomic polynomial. """
raise NotImplementedError
def __abs__(f):
return f.abs()
def __neg__(f):
return f.neg()
def __add__(f, g):
if isinstance(g, DMP):
return f.add(g)
else:
try:
return f.add_ground(g)
except CoercionFailed:
return NotImplemented
def __radd__(f, g):
return f.__add__(g)
def __sub__(f, g):
if isinstance(g, DMP):
return f.sub(g)
else:
try:
return f.sub_ground(g)
except CoercionFailed:
return NotImplemented
def __rsub__(f, g):
return (-f).__add__(g)
def __mul__(f, g):
if isinstance(g, DMP):
return f.mul(g)
else:
try:
return f.mul_ground(g)
except CoercionFailed:
return NotImplemented
def __rmul__(f, g):
return f.__mul__(g)
def __truediv__(f, g):
if isinstance(g, DMP):
return f.exquo(g)
else:
try:
return f.mul_ground(g)
except CoercionFailed:
return NotImplemented
def __rtruediv__(f, g):
if isinstance(g, DMP):
return g.exquo(f)
else:
try:
return f._one().mul_ground(g).exquo(f)
except CoercionFailed:
return NotImplemented
def __pow__(f, n):
return f.pow(n)
def __divmod__(f, g):
return f.div(g)
def __mod__(f, g):
return f.rem(g)
def __floordiv__(f, g):
if isinstance(g, DMP):
return f.quo(g)
else:
try:
return f.quo_ground(g)
except TypeError:
return NotImplemented
def __eq__(f, g):
if f is g:
return True
if not isinstance(g, DMP):
return NotImplemented
try:
F, G = f.unify_DMP(g)
except UnificationFailed:
return False
else:
return F._strict_eq(G)
def _strict_eq(f, g):
raise NotImplementedError
def eq(f, g, strict=False):
if not strict:
return f == g
else:
return f._strict_eq(g)
def ne(f, g, strict=False):
return not f.eq(g, strict=strict)
def __lt__(f, g):
F, G = f.unify_DMP(g)
return F.to_list() < G.to_list()
def __le__(f, g):
F, G = f.unify_DMP(g)
return F.to_list() <= G.to_list()
def __gt__(f, g):
F, G = f.unify_DMP(g)
return F.to_list() > G.to_list()
def __ge__(f, g):
F, G = f.unify_DMP(g)
return F.to_list() >= G.to_list()
def __bool__(f):
return not f.is_zero
class DMP_Python(DMP):
"""Dense Multivariate Polynomials over `K`. """
__slots__ = ('_rep', 'dom', 'lev')
@classmethod
def _new(cls, rep, dom, lev):
obj = object.__new__(cls)
obj._rep = rep
obj.lev = lev
obj.dom = dom
return obj
def _strict_eq(f, g):
if type(f) != type(g):
return False
return f.lev == g.lev and f.dom == g.dom and f._rep == g._rep
def per(f, rep):
"""Create a DMP out of the given representation. """
return f._new(rep, f.dom, f.lev)
def ground_new(f, coeff):
"""Construct a new ground instance of ``f``. """
return f._new(dmp_ground(coeff, f.lev), f.dom, f.lev)
def _one(f):
return f.one(f.lev, f.dom)
def unify(f, g):
"""Unify representations of two multivariate polynomials. """
# XXX: This function is not really used any more since there is
# unify_DMP now.
if not isinstance(g, DMP) or f.lev != g.lev:
raise UnificationFailed("Cannot unify %s with %s" % (f, g))
if f.dom == g.dom:
return f.lev, f.dom, f.per, f._rep, g._rep
else:
lev, dom = f.lev, f.dom.unify(g.dom)
F = dmp_convert(f._rep, lev, f.dom, dom)
G = dmp_convert(g._rep, lev, g.dom, dom)
def per(rep):
return f._new(rep, dom, lev)
return lev, dom, per, F, G
def to_DUP_Flint(f):
"""Convert ``f`` to a Flint representation. """
return DUP_Flint._new(f._rep, f.dom, f.lev)
def to_list(f):
"""Convert ``f`` to a list representation with native coefficients. """
return list(f._rep)
def to_tuple(f):
"""Convert ``f`` to a tuple representation with native coefficients. """
return dmp_to_tuple(f._rep, f.lev)
def _convert(f, dom):
"""Convert the ground domain of ``f``. """
return f._new(dmp_convert(f._rep, f.lev, f.dom, dom), dom, f.lev)
def _slice(f, m, n):
"""Take a continuous subsequence of terms of ``f``. """
rep = dup_slice(f._rep, m, n, f.dom)
return f._new(rep, f.dom, f.lev)
def _slice_lev(f, m, n, j):
"""Take a continuous subsequence of terms of ``f``. """
rep = dmp_slice_in(f._rep, m, n, j, f.lev, f.dom)
return f._new(rep, f.dom, f.lev)
def _terms(f, order=None):
"""Returns all non-zero terms from ``f`` in lex order. """
return dmp_list_terms(f._rep, f.lev, f.dom, order=order)
def _lift(f):
"""Convert algebraic coefficients to rationals. """
r = dmp_lift(f._rep, f.lev, f.dom)
return f._new(r, f.dom.dom, f.lev)
def deflate(f):
"""Reduce degree of `f` by mapping `x_i^m` to `y_i`. """
J, F = dmp_deflate(f._rep, f.lev, f.dom)
return J, f.per(F)
def inject(f, front=False):
"""Inject ground domain generators into ``f``. """
F, lev = dmp_inject(f._rep, f.lev, f.dom, front=front)
# XXX: domain and level changed here
return f._new(F, f.dom.dom, lev)
def eject(f, dom, front=False):
"""Eject selected generators into the ground domain. """
F = dmp_eject(f._rep, f.lev, dom, front=front)
# XXX: domain and level changed here
return f._new(F, dom, f.lev - len(dom.symbols))
def _exclude(f):
"""Remove useless generators from ``f``. """
J, F, u = dmp_exclude(f._rep, f.lev, f.dom)
# XXX: level changed here
return J, f._new(F, f.dom, u)
def _permute(f, P):
"""Returns a polynomial in `K[x_{P(1)}, ..., x_{P(n)}]`. """
return f.per(dmp_permute(f._rep, P, f.lev, f.dom))
def terms_gcd(f):
"""Remove GCD of terms from the polynomial ``f``. """
J, F = dmp_terms_gcd(f._rep, f.lev, f.dom)
return J, f.per(F)
def _add_ground(f, c):
"""Add an element of the ground domain to ``f``. """
return f.per(dmp_add_ground(f._rep, c, f.lev, f.dom))
def _sub_ground(f, c):
"""Subtract an element of the ground domain from ``f``. """
return f.per(dmp_sub_ground(f._rep, c, f.lev, f.dom))
def _mul_ground(f, c):
"""Multiply ``f`` by a an element of the ground domain. """
return f.per(dmp_mul_ground(f._rep, c, f.lev, f.dom))
def _quo_ground(f, c):
"""Quotient of ``f`` by a an element of the ground domain. """
return f.per(dmp_quo_ground(f._rep, c, f.lev, f.dom))
def _exquo_ground(f, c):
"""Exact quotient of ``f`` by a an element of the ground domain. """
return f.per(dmp_exquo_ground(f._rep, c, f.lev, f.dom))
def abs(f):
"""Make all coefficients in ``f`` positive. """
return f.per(dmp_abs(f._rep, f.lev, f.dom))
def neg(f):
"""Negate all coefficients in ``f``. """
return f.per(dmp_neg(f._rep, f.lev, f.dom))
def _add(f, g):
"""Add two multivariate polynomials ``f`` and ``g``. """
return f.per(dmp_add(f._rep, g._rep, f.lev, f.dom))
def _sub(f, g):
"""Subtract two multivariate polynomials ``f`` and ``g``. """
return f.per(dmp_sub(f._rep, g._rep, f.lev, f.dom))
def _mul(f, g):
"""Multiply two multivariate polynomials ``f`` and ``g``. """
return f.per(dmp_mul(f._rep, g._rep, f.lev, f.dom))
def sqr(f):
"""Square a multivariate polynomial ``f``. """
return f.per(dmp_sqr(f._rep, f.lev, f.dom))
def _pow(f, n):
"""Raise ``f`` to a non-negative power ``n``. """
return f.per(dmp_pow(f._rep, n, f.lev, f.dom))
def _pdiv(f, g):
"""Polynomial pseudo-division of ``f`` and ``g``. """
q, r = dmp_pdiv(f._rep, g._rep, f.lev, f.dom)
return f.per(q), f.per(r)
def _prem(f, g):
"""Polynomial pseudo-remainder of ``f`` and ``g``. """
return f.per(dmp_prem(f._rep, g._rep, f.lev, f.dom))
def _pquo(f, g):
"""Polynomial pseudo-quotient of ``f`` and ``g``. """
return f.per(dmp_pquo(f._rep, g._rep, f.lev, f.dom))
def _pexquo(f, g):
"""Polynomial exact pseudo-quotient of ``f`` and ``g``. """
return f.per(dmp_pexquo(f._rep, g._rep, f.lev, f.dom))
def _div(f, g):
"""Polynomial division with remainder of ``f`` and ``g``. """
q, r = dmp_div(f._rep, g._rep, f.lev, f.dom)
return f.per(q), f.per(r)
def _rem(f, g):
"""Computes polynomial remainder of ``f`` and ``g``. """
return f.per(dmp_rem(f._rep, g._rep, f.lev, f.dom))
def _quo(f, g):
"""Computes polynomial quotient of ``f`` and ``g``. """
return f.per(dmp_quo(f._rep, g._rep, f.lev, f.dom))
def _exquo(f, g):
"""Computes polynomial exact quotient of ``f`` and ``g``. """
return f.per(dmp_exquo(f._rep, g._rep, f.lev, f.dom))
def _degree(f, j=0):
"""Returns the leading degree of ``f`` in ``x_j``. """
return dmp_degree_in(f._rep, j, f.lev)
def degree_list(f):
"""Returns a list of degrees of ``f``. """
return dmp_degree_list(f._rep, f.lev)
def total_degree(f):
"""Returns the total degree of ``f``. """
return max(sum(m) for m in f.monoms())
def LC(f):
"""Returns the leading coefficient of ``f``. """
return dmp_ground_LC(f._rep, f.lev, f.dom)
def TC(f):
"""Returns the trailing coefficient of ``f``. """
return dmp_ground_TC(f._rep, f.lev, f.dom)
def _nth(f, N):
"""Returns the ``n``-th coefficient of ``f``. """
return dmp_ground_nth(f._rep, N, f.lev, f.dom)
def max_norm(f):
"""Returns maximum norm of ``f``. """
return dmp_max_norm(f._rep, f.lev, f.dom)
def l1_norm(f):
"""Returns l1 norm of ``f``. """
return dmp_l1_norm(f._rep, f.lev, f.dom)
def l2_norm_squared(f):
"""Return squared l2 norm of ``f``. """
return dmp_l2_norm_squared(f._rep, f.lev, f.dom)
def clear_denoms(f):
"""Clear denominators, but keep the ground domain. """
coeff, F = dmp_clear_denoms(f._rep, f.lev, f.dom)
return coeff, f.per(F)
def _integrate(f, m=1, j=0):
"""Computes the ``m``-th order indefinite integral of ``f`` in ``x_j``. """
return f.per(dmp_integrate_in(f._rep, m, j, f.lev, f.dom))
def _diff(f, m=1, j=0):
"""Computes the ``m``-th order derivative of ``f`` in ``x_j``. """
return f.per(dmp_diff_in(f._rep, m, j, f.lev, f.dom))
def _eval(f, a):
return dmp_eval_in(f._rep, f.dom.convert(a), 0, f.lev, f.dom)
def _eval_lev(f, a, j):
rep = dmp_eval_in(f._rep, f.dom.convert(a), j, f.lev, f.dom)
return f.new(rep, f.dom, f.lev - 1)
def _half_gcdex(f, g):
"""Half extended Euclidean algorithm, if univariate. """
s, h = dup_half_gcdex(f._rep, g._rep, f.dom)
return f.per(s), f.per(h)
def _gcdex(f, g):
"""Extended Euclidean algorithm, if univariate. """
s, t, h = dup_gcdex(f._rep, g._rep, f.dom)
return f.per(s), f.per(t), f.per(h)
def _invert(f, g):
"""Invert ``f`` modulo ``g``, if possible. """
s = dup_invert(f._rep, g._rep, f.dom)
return f.per(s)
def _revert(f, n):
"""Compute ``f**(-1)`` mod ``x**n``. """
return f.per(dup_revert(f._rep, n, f.dom))
def _subresultants(f, g):
"""Computes subresultant PRS sequence of ``f`` and ``g``. """
R = dmp_subresultants(f._rep, g._rep, f.lev, f.dom)
return list(map(f.per, R))
def _resultant_includePRS(f, g):
"""Computes resultant of ``f`` and ``g`` via PRS. """
res, R = dmp_resultant(f._rep, g._rep, f.lev, f.dom, includePRS=True)
if f.lev:
res = f.new(res, f.dom, f.lev - 1)
return res, list(map(f.per, R))
def _resultant(f, g):
res = dmp_resultant(f._rep, g._rep, f.lev, f.dom)
if f.lev:
res = f.new(res, f.dom, f.lev - 1)
return res
def discriminant(f):
"""Computes discriminant of ``f``. """
res = dmp_discriminant(f._rep, f.lev, f.dom)
if f.lev:
res = f.new(res, f.dom, f.lev - 1)
return res
def _cofactors(f, g):
"""Returns GCD of ``f`` and ``g`` and their cofactors. """
h, cff, cfg = dmp_inner_gcd(f._rep, g._rep, f.lev, f.dom)
return f.per(h), f.per(cff), f.per(cfg)
def _gcd(f, g):
"""Returns polynomial GCD of ``f`` and ``g``. """
return f.per(dmp_gcd(f._rep, g._rep, f.lev, f.dom))
def _lcm(f, g):
"""Returns polynomial LCM of ``f`` and ``g``. """
return f.per(dmp_lcm(f._rep, g._rep, f.lev, f.dom))
def _cancel(f, g):
"""Cancel common factors in a rational function ``f/g``. """
cF, cG, F, G = dmp_cancel(f._rep, g._rep, f.lev, f.dom, include=False)
return cF, cG, f.per(F), f.per(G)
def _cancel_include(f, g):
"""Cancel common factors in a rational function ``f/g``. """
F, G = dmp_cancel(f._rep, g._rep, f.lev, f.dom, include=True)
return f.per(F), f.per(G)
def _trunc(f, p):
"""Reduce ``f`` modulo a constant ``p``. """
return f.per(dmp_ground_trunc(f._rep, p, f.lev, f.dom))
def monic(f):
"""Divides all coefficients by ``LC(f)``. """
return f.per(dmp_ground_monic(f._rep, f.lev, f.dom))
def content(f):
"""Returns GCD of polynomial coefficients. """
return dmp_ground_content(f._rep, f.lev, f.dom)
def primitive(f):
"""Returns content and a primitive form of ``f``. """
cont, F = dmp_ground_primitive(f._rep, f.lev, f.dom)
return cont, f.per(F)
def _compose(f, g):
"""Computes functional composition of ``f`` and ``g``. """
return f.per(dmp_compose(f._rep, g._rep, f.lev, f.dom))
def _decompose(f):
"""Computes functional decomposition of ``f``. """
return list(map(f.per, dup_decompose(f._rep, f.dom)))
def _shift(f, a):
"""Efficiently compute Taylor shift ``f(x + a)``. """
return f.per(dup_shift(f._rep, a, f.dom))
def _shift_list(f, a):
"""Efficiently compute Taylor shift ``f(X + A)``. """
return f.per(dmp_shift(f._rep, a, f.lev, f.dom))
def _transform(f, p, q):
"""Evaluate functional transformation ``q**n * f(p/q)``."""
return f.per(dup_transform(f._rep, p._rep, q._rep, f.dom))
def _sturm(f):
"""Computes the Sturm sequence of ``f``. """
return list(map(f.per, dup_sturm(f._rep, f.dom)))
def _cauchy_upper_bound(f):
"""Computes the Cauchy upper bound on the roots of ``f``. """
return dup_cauchy_upper_bound(f._rep, f.dom)
def _cauchy_lower_bound(f):
"""Computes the Cauchy lower bound on the nonzero roots of ``f``. """
return dup_cauchy_lower_bound(f._rep, f.dom)
def _mignotte_sep_bound_squared(f):
"""Computes the squared Mignotte bound on root separations of ``f``. """
return dup_mignotte_sep_bound_squared(f._rep, f.dom)
def _gff_list(f):
"""Computes greatest factorial factorization of ``f``. """
return [ (f.per(g), k) for g, k in dup_gff_list(f._rep, f.dom) ]
def norm(f):
"""Computes ``Norm(f)``."""
r = dmp_norm(f._rep, f.lev, f.dom)
return f.new(r, f.dom.dom, f.lev)
def sqf_norm(f):
"""Computes square-free norm of ``f``. """
s, g, r = dmp_sqf_norm(f._rep, f.lev, f.dom)
return s, f.per(g), f.new(r, f.dom.dom, f.lev)
def sqf_part(f):
"""Computes square-free part of ``f``. """
return f.per(dmp_sqf_part(f._rep, f.lev, f.dom))
def sqf_list(f, all=False):
"""Returns a list of square-free factors of ``f``. """
coeff, factors = dmp_sqf_list(f._rep, f.lev, f.dom, all)
return coeff, [ (f.per(g), k) for g, k in factors ]
def sqf_list_include(f, all=False):
"""Returns a list of square-free factors of ``f``. """
factors = dmp_sqf_list_include(f._rep, f.lev, f.dom, all)
return [ (f.per(g), k) for g, k in factors ]
def factor_list(f):
"""Returns a list of irreducible factors of ``f``. """
coeff, factors = dmp_factor_list(f._rep, f.lev, f.dom)
return coeff, [ (f.per(g), k) for g, k in factors ]
def factor_list_include(f):
"""Returns a list of irreducible factors of ``f``. """
factors = dmp_factor_list_include(f._rep, f.lev, f.dom)
return [ (f.per(g), k) for g, k in factors ]
def _isolate_real_roots(f, eps, inf, sup, fast):
return dup_isolate_real_roots(f._rep, f.dom, eps=eps, inf=inf, sup=sup, fast=fast)
def _isolate_real_roots_sqf(f, eps, inf, sup, fast):
return dup_isolate_real_roots_sqf(f._rep, f.dom, eps=eps, inf=inf, sup=sup, fast=fast)
def _isolate_all_roots(f, eps, inf, sup, fast):
return dup_isolate_all_roots(f._rep, f.dom, eps=eps, inf=inf, sup=sup, fast=fast)
def _isolate_all_roots_sqf(f, eps, inf, sup, fast):
return dup_isolate_all_roots_sqf(f._rep, f.dom, eps=eps, inf=inf, sup=sup, fast=fast)
def _refine_real_root(f, s, t, eps, steps, fast):
return dup_refine_real_root(f._rep, s, t, f.dom, eps=eps, steps=steps, fast=fast)
def count_real_roots(f, inf=None, sup=None):
"""Return the number of real roots of ``f`` in ``[inf, sup]``. """
return dup_count_real_roots(f._rep, f.dom, inf=inf, sup=sup)
def count_complex_roots(f, inf=None, sup=None):
"""Return the number of complex roots of ``f`` in ``[inf, sup]``. """
return dup_count_complex_roots(f._rep, f.dom, inf=inf, sup=sup)
@property
def is_zero(f):
"""Returns ``True`` if ``f`` is a zero polynomial. """
return dmp_zero_p(f._rep, f.lev)
@property
def is_one(f):
"""Returns ``True`` if ``f`` is a unit polynomial. """
return dmp_one_p(f._rep, f.lev, f.dom)
@property
def is_ground(f):
"""Returns ``True`` if ``f`` is an element of the ground domain. """
return dmp_ground_p(f._rep, None, f.lev)
@property
def is_sqf(f):
"""Returns ``True`` if ``f`` is a square-free polynomial. """
return dmp_sqf_p(f._rep, f.lev, f.dom)
@property
def is_monic(f):
"""Returns ``True`` if the leading coefficient of ``f`` is one. """
return f.dom.is_one(dmp_ground_LC(f._rep, f.lev, f.dom))
@property
def is_primitive(f):
"""Returns ``True`` if the GCD of the coefficients of ``f`` is one. """
return f.dom.is_one(dmp_ground_content(f._rep, f.lev, f.dom))
@property
def is_linear(f):
"""Returns ``True`` if ``f`` is linear in all its variables. """
return all(sum(monom) <= 1 for monom in dmp_to_dict(f._rep, f.lev, f.dom).keys())
@property
def is_quadratic(f):
"""Returns ``True`` if ``f`` is quadratic in all its variables. """
return all(sum(monom) <= 2 for monom in dmp_to_dict(f._rep, f.lev, f.dom).keys())
@property
def is_monomial(f):
"""Returns ``True`` if ``f`` is zero or has only one term. """
return len(f.to_dict()) <= 1
@property
def is_homogeneous(f):
"""Returns ``True`` if ``f`` is a homogeneous polynomial. """
return f.homogeneous_order() is not None
@property
def is_irreducible(f):
"""Returns ``True`` if ``f`` has no factors over its domain. """
return dmp_irreducible_p(f._rep, f.lev, f.dom)
@property
def is_cyclotomic(f):
"""Returns ``True`` if ``f`` is a cyclotomic polynomial. """
if not f.lev:
return dup_cyclotomic_p(f._rep, f.dom)
else:
return False
class DUP_Flint(DMP):
"""Dense Multivariate Polynomials over `K`. """
lev = 0
__slots__ = ('_rep', 'dom', '_cls')
def __reduce__(self):
return self.__class__, (self.to_list(), self.dom, self.lev)
@classmethod
def _new(cls, rep, dom, lev):
rep = cls._flint_poly(rep[::-1], dom, lev)
return cls.from_rep(rep, dom)
def to_list(f):
"""Convert ``f`` to a list representation with native coefficients. """
return f._rep.coeffs()[::-1]
@classmethod
def _flint_poly(cls, rep, dom, lev):
assert dom in _flint_domains
assert lev == 0
flint_cls = cls._get_flint_poly_cls(dom)
return flint_cls(rep)
@classmethod
def _get_flint_poly_cls(cls, dom):
if dom.is_ZZ:
return flint.fmpz_poly
elif dom.is_QQ:
return flint.fmpq_poly
else:
raise RuntimeError("Domain %s is not supported with flint" % dom)
@classmethod
def from_rep(cls, rep, dom):
"""Create a DMP from the given representation. """
if dom.is_ZZ:
assert isinstance(rep, flint.fmpz_poly)
_cls = flint.fmpz_poly
elif dom.is_QQ:
assert isinstance(rep, flint.fmpq_poly)
_cls = flint.fmpq_poly
else:
raise RuntimeError("Domain %s is not supported with flint" % dom)
obj = object.__new__(cls)
obj.dom = dom
obj._rep = rep
obj._cls = _cls
return obj
def _strict_eq(f, g):
if type(f) != type(g):
return False
return f.dom == g.dom and f._rep == g._rep
def ground_new(f, coeff):
"""Construct a new ground instance of ``f``. """
return f.from_rep(f._cls([coeff]), f.dom)
def _one(f):
return f.ground_new(f.dom.one)
def unify(f, g):
"""Unify representations of two polynomials. """
raise RuntimeError
def to_DMP_Python(f):
"""Convert ``f`` to a Python native representation. """
return DMP_Python._new(f.to_list(), f.dom, f.lev)
def to_tuple(f):
"""Convert ``f`` to a tuple representation with native coefficients. """
return tuple(f.to_list())
def _convert(f, dom):
"""Convert the ground domain of ``f``. """
if dom == QQ and f.dom == ZZ:
return f.from_rep(flint.fmpq_poly(f._rep), dom)
elif dom == ZZ and f.dom == QQ:
# XXX: python-flint should provide a faster way to do this.
return f.to_DMP_Python()._convert(dom).to_DUP_Flint()
else:
raise RuntimeError(f"DUP_Flint: Cannot convert {f.dom} to {dom}")
def _slice(f, m, n):
"""Take a continuous subsequence of terms of ``f``. """
coeffs = f._rep.coeffs()[m:n]
return f.from_rep(f._cls(coeffs), f.dom)
def _slice_lev(f, m, n, j):
"""Take a continuous subsequence of terms of ``f``. """
# Only makes sense for multivariate polynomials
raise NotImplementedError
def _terms(f, order=None):
"""Returns all non-zero terms from ``f`` in lex order. """
if order is None or order.alias == 'lex':
terms = [ ((n,), c) for n, c in enumerate(f._rep.coeffs()) if c ]
return terms[::-1]
else:
# XXX: InverseOrder (ilex) comes here. We could handle that case
# efficiently by reversing the coefficients but it is not clear
# how to test if the order is InverseOrder.
#
# Otherwise why would the order ever be different for univariate
# polynomials?
return f.to_DMP_Python()._terms(order=order)
def _lift(f):
"""Convert algebraic coefficients to rationals. """
# This is for algebraic number fields which DUP_Flint does not support
raise NotImplementedError
def deflate(f):
"""Reduce degree of `f` by mapping `x_i^m` to `y_i`. """
# XXX: Check because otherwise this segfaults with python-flint:
#
# >>> flint.fmpz_poly([]).deflation()
# Exception (fmpz_poly_deflate). Division by zero.
# Aborted (core dumped
#
if f.is_zero:
return (1,), f
g, n = f._rep.deflation()
return (n,), f.from_rep(g, f.dom)
def inject(f, front=False):
"""Inject ground domain generators into ``f``. """
# Ground domain would need to be a poly ring
raise NotImplementedError
def eject(f, dom, front=False):
"""Eject selected generators into the ground domain. """
# Only makes sense for multivariate polynomials
raise NotImplementedError
def _exclude(f):
"""Remove useless generators from ``f``. """
# Only makes sense for multivariate polynomials
raise NotImplementedError
def _permute(f, P):
"""Returns a polynomial in `K[x_{P(1)}, ..., x_{P(n)}]`. """
# Only makes sense for multivariate polynomials
raise NotImplementedError
def terms_gcd(f):
"""Remove GCD of terms from the polynomial ``f``. """
# XXX: python-flint should have primitive, content, etc methods.
J, F = f.to_DMP_Python().terms_gcd()
return J, F.to_DUP_Flint()
def _add_ground(f, c):
"""Add an element of the ground domain to ``f``. """
return f.from_rep(f._rep + c, f.dom)
def _sub_ground(f, c):
"""Subtract an element of the ground domain from ``f``. """
return f.from_rep(f._rep - c, f.dom)
def _mul_ground(f, c):
"""Multiply ``f`` by a an element of the ground domain. """
return f.from_rep(f._rep * c, f.dom)
def _quo_ground(f, c):
"""Quotient of ``f`` by a an element of the ground domain. """
return f.from_rep(f._rep // c, f.dom)
def _exquo_ground(f, c):
"""Exact quotient of ``f`` by a an element of the ground domain. """
q, r = divmod(f._rep, c)
if r:
raise ExactQuotientFailed(f, c)
return f.from_rep(q, f.dom)
def abs(f):
"""Make all coefficients in ``f`` positive. """
return f.to_DMP_Python().abs().to_DUP_Flint()
def neg(f):
"""Negate all coefficients in ``f``. """
return f.from_rep(-f._rep, f.dom)
def _add(f, g):
"""Add two multivariate polynomials ``f`` and ``g``. """
return f.from_rep(f._rep + g._rep, f.dom)
def _sub(f, g):
"""Subtract two multivariate polynomials ``f`` and ``g``. """
return f.from_rep(f._rep - g._rep, f.dom)
def _mul(f, g):
"""Multiply two multivariate polynomials ``f`` and ``g``. """
return f.from_rep(f._rep * g._rep, f.dom)
def sqr(f):
"""Square a multivariate polynomial ``f``. """
return f.from_rep(f._rep ** 2, f.dom)
def _pow(f, n):
"""Raise ``f`` to a non-negative power ``n``. """
return f.from_rep(f._rep ** n, f.dom)
def _pdiv(f, g):
"""Polynomial pseudo-division of ``f`` and ``g``. """
d = f.degree() - g.degree() + 1
q, r = divmod(g.LC()**d * f._rep, g._rep)
return f.from_rep(q, f.dom), f.from_rep(r, f.dom)
def _prem(f, g):
"""Polynomial pseudo-remainder of ``f`` and ``g``. """
d = f.degree() - g.degree() + 1
q = (g.LC()**d * f._rep) % g._rep
return f.from_rep(q, f.dom)
def _pquo(f, g):
"""Polynomial pseudo-quotient of ``f`` and ``g``. """
d = f.degree() - g.degree() + 1
r = (g.LC()**d * f._rep) // g._rep
return f.from_rep(r, f.dom)
def _pexquo(f, g):
"""Polynomial exact pseudo-quotient of ``f`` and ``g``. """
d = f.degree() - g.degree() + 1
q, r = divmod(g.LC()**d * f._rep, g._rep)
if r:
raise ExactQuotientFailed(f, g)
return f.from_rep(q, f.dom)
def _div(f, g):
"""Polynomial division with remainder of ``f`` and ``g``. """
if f.dom.is_Field:
q, r = divmod(f._rep, g._rep)
return f.from_rep(q, f.dom), f.from_rep(r, f.dom)
else:
# XXX: python-flint defines division in ZZ[x] differently
q, r = f.to_DMP_Python()._div(g.to_DMP_Python())
return q.to_DUP_Flint(), r.to_DUP_Flint()
def _rem(f, g):
"""Computes polynomial remainder of ``f`` and ``g``. """
return f.from_rep(f._rep % g._rep, f.dom)
def _quo(f, g):
"""Computes polynomial quotient of ``f`` and ``g``. """
return f.from_rep(f._rep // g._rep, f.dom)
def _exquo(f, g):
"""Computes polynomial exact quotient of ``f`` and ``g``. """
q, r = f._div(g)
if r:
raise ExactQuotientFailed(f, g)
return q
def _degree(f, j=0):
"""Returns the leading degree of ``f`` in ``x_j``. """
d = f._rep.degree()
if d == -1:
d = ninf
return d
def degree_list(f):
"""Returns a list of degrees of ``f``. """
return ( f._degree() ,)
def total_degree(f):
"""Returns the total degree of ``f``. """
return f._degree()
def LC(f):
"""Returns the leading coefficient of ``f``. """
return f._rep[f._rep.degree()]
def TC(f):
"""Returns the trailing coefficient of ``f``. """
return f._rep[0]
def _nth(f, N):
"""Returns the ``n``-th coefficient of ``f``. """
[n] = N
return f._rep[n]
def max_norm(f):
"""Returns maximum norm of ``f``. """
return f.to_DMP_Python().max_norm()
def l1_norm(f):
"""Returns l1 norm of ``f``. """
return f.to_DMP_Python().l1_norm()
def l2_norm_squared(f):
"""Return squared l2 norm of ``f``. """
return f.to_DMP_Python().l2_norm_squared()
def clear_denoms(f):
"""Clear denominators, but keep the ground domain. """
denom = f._rep.denom()
numer = f.from_rep(f._cls(f._rep.numer()), f.dom)
return denom, numer
def _integrate(f, m=1, j=0):
"""Computes the ``m``-th order indefinite integral of ``f`` in ``x_j``. """
assert j == 0
if f.dom.is_QQ:
rep = f._rep
for i in range(m):
rep = rep.integral()
return f.from_rep(rep, f.dom)
else:
return f.to_DMP_Python()._integrate(m=m, j=j).to_DUP_Flint()
def _diff(f, m=1, j=0):
"""Computes the ``m``-th order derivative of ``f``. """
assert j == 0
rep = f._rep
for i in range(m):
rep = rep.derivative()
return f.from_rep(rep, f.dom)
def _eval(f, a):
return f.to_DMP_Python()._eval(a)
def _eval_lev(f, a, j):
# Only makes sense for multivariate polynomials
raise NotImplementedError
def _half_gcdex(f, g):
"""Half extended Euclidean algorithm. """
s, h = f.to_DMP_Python()._half_gcdex(g.to_DMP_Python())
return s.to_DUP_Flint(), h.to_DUP_Flint()
def _gcdex(f, g):
"""Extended Euclidean algorithm. """
h, s, t = f._rep.xgcd(g._rep)
return f.from_rep(s, f.dom), f.from_rep(t, f.dom), f.from_rep(h, f.dom)
def _invert(f, g):
"""Invert ``f`` modulo ``g``, if possible. """
if f.dom.is_QQ:
gcd, F_inv, _ = f._rep.xgcd(g._rep)
if gcd != 1:
raise NotInvertible("zero divisor")
return f.from_rep(F_inv, f.dom)
else:
return f.to_DMP_Python()._invert(g.to_DMP_Python()).to_DUP_Flint()
def _revert(f, n):
"""Compute ``f**(-1)`` mod ``x**n``. """
return f.to_DMP_Python()._revert(n).to_DUP_Flint()
def _subresultants(f, g):
"""Computes subresultant PRS sequence of ``f`` and ``g``. """
R = f.to_DMP_Python()._subresultants(g.to_DMP_Python())
return [ g.to_DUP_Flint() for g in R ]
def _resultant_includePRS(f, g):
"""Computes resultant of ``f`` and ``g`` via PRS. """
res, R = f.to_DMP_Python()._resultant_includePRS(g.to_DMP_Python())
return res, [ g.to_DUP_Flint() for g in R ]
def _resultant(f, g):
"""Computes resultant of ``f`` and ``g``. """
return f.to_DMP_Python()._resultant(g.to_DMP_Python())
def discriminant(f):
"""Computes discriminant of ``f``. """
return f.to_DMP_Python().discriminant()
def _cofactors(f, g):
"""Returns GCD of ``f`` and ``g`` and their cofactors. """
h = f.gcd(g)
return h, f.exquo(h), g.exquo(h)
def _gcd(f, g):
"""Returns polynomial GCD of ``f`` and ``g``. """
return f.from_rep(f._rep.gcd(g._rep), f.dom)
def _lcm(f, g):
"""Returns polynomial LCM of ``f`` and ``g``. """
# XXX: python-flint should have a lcm method
if not (f and g):
return f.ground_new(f.dom.zero)
l = f._mul(g)._exquo(f._gcd(g))
if l.dom.is_Field:
l = l.monic()
elif l.LC() < 0:
l = l.neg()
return l
def _cancel(f, g):
"""Cancel common factors in a rational function ``f/g``. """
# Think carefully about how to handle denominators and coefficient
# canonicalisation if more domains are permitted...
assert f.dom == g.dom in (ZZ, QQ)
if f.dom.is_QQ:
cG, F = f.clear_denoms()
cF, G = g.clear_denoms()
else:
cG, F = f.dom.one, f
cF, G = g.dom.one, g
cH = cF.gcd(cG)
cF, cG = cF // cH, cG // cH
H = F._gcd(G)
F, G = F.exquo(H), G.exquo(H)
f_neg = F.LC() < 0
g_neg = G.LC() < 0
if f_neg and g_neg:
F, G = F.neg(), G.neg()
elif f_neg:
cF, F = -cF, F.neg()
elif g_neg:
cF, G = -cF, G.neg()
return cF, cG, F, G
def _cancel_include(f, g):
"""Cancel common factors in a rational function ``f/g``. """
cF, cG, F, G = f._cancel(g)
return F._mul_ground(cF), G._mul_ground(cG)
def _trunc(f, p):
"""Reduce ``f`` modulo a constant ``p``. """
return f.to_DMP_Python()._trunc(p).to_DUP_Flint()
def monic(f):
"""Divides all coefficients by ``LC(f)``. """
return f._exquo_ground(f.LC())
def content(f):
"""Returns GCD of polynomial coefficients. """
# XXX: python-flint should have a content method
return f.to_DMP_Python().content()
def primitive(f):
"""Returns content and a primitive form of ``f``. """
cont = f.content()
prim = f._exquo_ground(cont)
return cont, prim
def _compose(f, g):
"""Computes functional composition of ``f`` and ``g``. """
return f.from_rep(f._rep(g._rep), f.dom)
def _decompose(f):
"""Computes functional decomposition of ``f``. """
return [ g.to_DUP_Flint() for g in f.to_DMP_Python()._decompose() ]
def _shift(f, a):
"""Efficiently compute Taylor shift ``f(x + a)``. """
x_plus_a = f._cls([a, f.dom.one])
return f.from_rep(f._rep(x_plus_a), f.dom)
def _transform(f, p, q):
"""Evaluate functional transformation ``q**n * f(p/q)``."""
F, P, Q = f.to_DMP_Python(), p.to_DMP_Python(), q.to_DMP_Python()
return F.transform(P, Q).to_DUP_Flint()
def _sturm(f):
"""Computes the Sturm sequence of ``f``. """
return [ g.to_DUP_Flint() for g in f.to_DMP_Python()._sturm() ]
def _cauchy_upper_bound(f):
"""Computes the Cauchy upper bound on the roots of ``f``. """
return f.to_DMP_Python()._cauchy_upper_bound()
def _cauchy_lower_bound(f):
"""Computes the Cauchy lower bound on the nonzero roots of ``f``. """
return f.to_DMP_Python()._cauchy_lower_bound()
def _mignotte_sep_bound_squared(f):
"""Computes the squared Mignotte bound on root separations of ``f``. """
return f.to_DMP_Python()._mignotte_sep_bound_squared()
def _gff_list(f):
"""Computes greatest factorial factorization of ``f``. """
F = f.to_DMP_Python()
return [ (g.to_DUP_Flint(), k) for g, k in F.gff_list() ]
def norm(f):
"""Computes ``Norm(f)``."""
# This is for algebraic number fields which DUP_Flint does not support
raise NotImplementedError
def sqf_norm(f):
"""Computes square-free norm of ``f``. """
# This is for algebraic number fields which DUP_Flint does not support
raise NotImplementedError
def sqf_part(f):
"""Computes square-free part of ``f``. """
return f._exquo(f._gcd(f._diff()))
def sqf_list(f, all=False):
"""Returns a list of square-free factors of ``f``. """
coeff, factors = f.to_DMP_Python().sqf_list(all=all)
return coeff, [ (g.to_DUP_Flint(), k) for g, k in factors ]
def sqf_list_include(f, all=False):
"""Returns a list of square-free factors of ``f``. """
factors = f.to_DMP_Python().sqf_list_include(all=all)
return [ (g.to_DUP_Flint(), k) for g, k in factors ]
def factor_list(f):
"""Returns a list of irreducible factors of ``f``. """
if f.dom.is_ZZ:
# python-flint matches polys here
coeff, factors = f._rep.factor()
factors = [ (f.from_rep(g, f.dom), k) for g, k in factors ]
elif f.dom.is_QQ:
# python-flint returns monic factors over QQ whereas polys returns
# denominator free factors.
coeff, factors = f._rep.factor()
factors_monic = [ (f.from_rep(g, f.dom), k) for g, k in factors ]
# Absorb the denominators into coeff
factors = []
for g, k in factors_monic:
d, g = g.clear_denoms()
coeff /= d**k
factors.append((g, k))
else:
# Check carefully when adding more domains here...
raise RuntimeError("Domain %s is not supported with flint" % f.dom)
# We need to match the way that polys orders the factors
factors = f._sort_factors(factors)
return coeff, factors
def factor_list_include(f):
"""Returns a list of irreducible factors of ``f``. """
# XXX: factor_list_include seems to be broken in general:
#
# >>> Poly(2*(x - 1)**3, x).factor_list_include()
# [(Poly(2*x - 2, x, domain='ZZ'), 3)]
#
# Let's not try to implement it here.
factors = f.to_DMP_Python().factor_list_include()
return [ (g.to_DUP_Flint(), k) for g, k in factors ]
def _sort_factors(f, factors):
"""Sort a list of factors to canonical order. """
# Convert the factors to lists and use _sort_factors from polys
factors = [ (g.to_list(), k) for g, k in factors ]
factors = _sort_factors(factors, multiple=True)
to_dup_flint = lambda g: f.from_rep(f._cls(g[::-1]), f.dom)
return [ (to_dup_flint(g), k) for g, k in factors ]
def _isolate_real_roots(f, eps, inf, sup, fast):
return f.to_DMP_Python()._isolate_real_roots(eps, inf, sup, fast)
def _isolate_real_roots_sqf(f, eps, inf, sup, fast):
return f.to_DMP_Python()._isolate_real_roots_sqf(eps, inf, sup, fast)
def _isolate_all_roots(f, eps, inf, sup, fast):
return f.to_DMP_Python()._isolate_all_roots(eps, inf, sup, fast)
def _isolate_all_roots_sqf(f, eps, inf, sup, fast):
return f.to_DMP_Python()._isolate_all_roots_sqf(eps, inf, sup, fast)
def _refine_real_root(f, s, t, eps, steps, fast):
return f.to_DMP_Python()._refine_real_root(s, t, eps, steps, fast)
def count_real_roots(f, inf=None, sup=None):
"""Return the number of real roots of ``f`` in ``[inf, sup]``. """
return f.to_DMP_Python().count_real_roots(inf=inf, sup=sup)
def count_complex_roots(f, inf=None, sup=None):
"""Return the number of complex roots of ``f`` in ``[inf, sup]``. """
return f.to_DMP_Python().count_complex_roots(inf=inf, sup=sup)
@property
def is_zero(f):
"""Returns ``True`` if ``f`` is a zero polynomial. """
return not f._rep
@property
def is_one(f):
"""Returns ``True`` if ``f`` is a unit polynomial. """
return f._rep == f.dom.one
@property
def is_ground(f):
"""Returns ``True`` if ``f`` is an element of the ground domain. """
return f._rep.degree() <= 0
@property
def is_linear(f):
"""Returns ``True`` if ``f`` is linear in all its variables. """
return f._rep.degree() <= 1
@property
def is_quadratic(f):
"""Returns ``True`` if ``f`` is quadratic in all its variables. """
return f._rep.degree() <= 2
@property
def is_monomial(f):
"""Returns ``True`` if ``f`` is zero or has only one term. """
return f.to_DMP_Python().is_monomial
@property
def is_monic(f):
"""Returns ``True`` if the leading coefficient of ``f`` is one. """
return f.LC() == f.dom.one
@property
def is_primitive(f):
"""Returns ``True`` if the GCD of the coefficients of ``f`` is one. """
return f.to_DMP_Python().is_primitive
@property
def is_homogeneous(f):
"""Returns ``True`` if ``f`` is a homogeneous polynomial. """
return f.to_DMP_Python().is_homogeneous
@property
def is_sqf(f):
"""Returns ``True`` if ``f`` is a square-free polynomial. """
return f.to_DMP_Python().is_sqf
@property
def is_irreducible(f):
"""Returns ``True`` if ``f`` has no factors over its domain. """
return f.to_DMP_Python().is_irreducible
@property
def is_cyclotomic(f):
"""Returns ``True`` if ``f`` is a cyclotomic polynomial. """
if f.dom.is_ZZ:
return bool(f._rep.is_cyclotomic())
else:
return f.to_DMP_Python().is_cyclotomic
def init_normal_DMF(num, den, lev, dom):
return DMF(dmp_normal(num, lev, dom),
dmp_normal(den, lev, dom), dom, lev)
class DMF(PicklableWithSlots, CantSympify):
"""Dense Multivariate Fractions over `K`. """
__slots__ = ('num', 'den', 'lev', 'dom')
def __init__(self, rep, dom, lev=None):
num, den, lev = self._parse(rep, dom, lev)
num, den = dmp_cancel(num, den, lev, dom)
self.num = num
self.den = den
self.lev = lev
self.dom = dom
@classmethod
def new(cls, rep, dom, lev=None):
num, den, lev = cls._parse(rep, dom, lev)
obj = object.__new__(cls)
obj.num = num
obj.den = den
obj.lev = lev
obj.dom = dom
return obj
def ground_new(self, rep):
return self.new(rep, self.dom, self.lev)
@classmethod
def _parse(cls, rep, dom, lev=None):
if isinstance(rep, tuple):
num, den = rep
if lev is not None:
if isinstance(num, dict):
num = dmp_from_dict(num, lev, dom)
if isinstance(den, dict):
den = dmp_from_dict(den, lev, dom)
else:
num, num_lev = dmp_validate(num)
den, den_lev = dmp_validate(den)
if num_lev == den_lev:
lev = num_lev
else:
raise ValueError('inconsistent number of levels')
if dmp_zero_p(den, lev):
raise ZeroDivisionError('fraction denominator')
if dmp_zero_p(num, lev):
den = dmp_one(lev, dom)
else:
if dmp_negative_p(den, lev, dom):
num = dmp_neg(num, lev, dom)
den = dmp_neg(den, lev, dom)
else:
num = rep
if lev is not None:
if isinstance(num, dict):
num = dmp_from_dict(num, lev, dom)
elif not isinstance(num, list):
num = dmp_ground(dom.convert(num), lev)
else:
num, lev = dmp_validate(num)
den = dmp_one(lev, dom)
return num, den, lev
def __repr__(f):
return "%s((%s, %s), %s)" % (f.__class__.__name__, f.num, f.den, f.dom)
def __hash__(f):
return hash((f.__class__.__name__, dmp_to_tuple(f.num, f.lev),
dmp_to_tuple(f.den, f.lev), f.lev, f.dom))
def poly_unify(f, g):
"""Unify a multivariate fraction and a polynomial. """
if not isinstance(g, DMP) or f.lev != g.lev:
raise UnificationFailed("Cannot unify %s with %s" % (f, g))
if f.dom == g.dom:
return (f.lev, f.dom, f.per, (f.num, f.den), g._rep)
else:
lev, dom = f.lev, f.dom.unify(g.dom)
F = (dmp_convert(f.num, lev, f.dom, dom),
dmp_convert(f.den, lev, f.dom, dom))
G = dmp_convert(g._rep, lev, g.dom, dom)
def per(num, den, cancel=True, kill=False, lev=lev):
if kill:
if not lev:
return num/den
else:
lev = lev - 1
if cancel:
num, den = dmp_cancel(num, den, lev, dom)
return f.__class__.new((num, den), dom, lev)
return lev, dom, per, F, G
def frac_unify(f, g):
"""Unify representations of two multivariate fractions. """
if not isinstance(g, DMF) or f.lev != g.lev:
raise UnificationFailed("Cannot unify %s with %s" % (f, g))
if f.dom == g.dom:
return (f.lev, f.dom, f.per, (f.num, f.den),
(g.num, g.den))
else:
lev, dom = f.lev, f.dom.unify(g.dom)
F = (dmp_convert(f.num, lev, f.dom, dom),
dmp_convert(f.den, lev, f.dom, dom))
G = (dmp_convert(g.num, lev, g.dom, dom),
dmp_convert(g.den, lev, g.dom, dom))
def per(num, den, cancel=True, kill=False, lev=lev):
if kill:
if not lev:
return num/den
else:
lev = lev - 1
if cancel:
num, den = dmp_cancel(num, den, lev, dom)
return f.__class__.new((num, den), dom, lev)
return lev, dom, per, F, G
def per(f, num, den, cancel=True, kill=False):
"""Create a DMF out of the given representation. """
lev, dom = f.lev, f.dom
if kill:
if not lev:
return num/den
else:
lev -= 1
if cancel:
num, den = dmp_cancel(num, den, lev, dom)
return f.__class__.new((num, den), dom, lev)
def half_per(f, rep, kill=False):
"""Create a DMP out of the given representation. """
lev = f.lev
if kill:
if not lev:
return rep
else:
lev -= 1
return DMP(rep, f.dom, lev)
@classmethod
def zero(cls, lev, dom):
return cls.new(0, dom, lev)
@classmethod
def one(cls, lev, dom):
return cls.new(1, dom, lev)
def numer(f):
"""Returns the numerator of ``f``. """
return f.half_per(f.num)
def denom(f):
"""Returns the denominator of ``f``. """
return f.half_per(f.den)
def cancel(f):
"""Remove common factors from ``f.num`` and ``f.den``. """
return f.per(f.num, f.den)
def neg(f):
"""Negate all coefficients in ``f``. """
return f.per(dmp_neg(f.num, f.lev, f.dom), f.den, cancel=False)
def add_ground(f, c):
"""Add an element of the ground domain to ``f``. """
return f + f.ground_new(c)
def add(f, g):
"""Add two multivariate fractions ``f`` and ``g``. """
if isinstance(g, DMP):
lev, dom, per, (F_num, F_den), G = f.poly_unify(g)
num, den = dmp_add_mul(F_num, F_den, G, lev, dom), F_den
else:
lev, dom, per, F, G = f.frac_unify(g)
(F_num, F_den), (G_num, G_den) = F, G
num = dmp_add(dmp_mul(F_num, G_den, lev, dom),
dmp_mul(F_den, G_num, lev, dom), lev, dom)
den = dmp_mul(F_den, G_den, lev, dom)
return per(num, den)
def sub(f, g):
"""Subtract two multivariate fractions ``f`` and ``g``. """
if isinstance(g, DMP):
lev, dom, per, (F_num, F_den), G = f.poly_unify(g)
num, den = dmp_sub_mul(F_num, F_den, G, lev, dom), F_den
else:
lev, dom, per, F, G = f.frac_unify(g)
(F_num, F_den), (G_num, G_den) = F, G
num = dmp_sub(dmp_mul(F_num, G_den, lev, dom),
dmp_mul(F_den, G_num, lev, dom), lev, dom)
den = dmp_mul(F_den, G_den, lev, dom)
return per(num, den)
def mul(f, g):
"""Multiply two multivariate fractions ``f`` and ``g``. """
if isinstance(g, DMP):
lev, dom, per, (F_num, F_den), G = f.poly_unify(g)
num, den = dmp_mul(F_num, G, lev, dom), F_den
else:
lev, dom, per, F, G = f.frac_unify(g)
(F_num, F_den), (G_num, G_den) = F, G
num = dmp_mul(F_num, G_num, lev, dom)
den = dmp_mul(F_den, G_den, lev, dom)
return per(num, den)
def pow(f, n):
"""Raise ``f`` to a non-negative power ``n``. """
if isinstance(n, int):
num, den = f.num, f.den
if n < 0:
num, den, n = den, num, -n
return f.per(dmp_pow(num, n, f.lev, f.dom),
dmp_pow(den, n, f.lev, f.dom), cancel=False)
else:
raise TypeError("``int`` expected, got %s" % type(n))
def quo(f, g):
"""Computes quotient of fractions ``f`` and ``g``. """
if isinstance(g, DMP):
lev, dom, per, (F_num, F_den), G = f.poly_unify(g)
num, den = F_num, dmp_mul(F_den, G, lev, dom)
else:
lev, dom, per, F, G = f.frac_unify(g)
(F_num, F_den), (G_num, G_den) = F, G
num = dmp_mul(F_num, G_den, lev, dom)
den = dmp_mul(F_den, G_num, lev, dom)
return per(num, den)
exquo = quo
def invert(f, check=True):
"""Computes inverse of a fraction ``f``. """
return f.per(f.den, f.num, cancel=False)
@property
def is_zero(f):
"""Returns ``True`` if ``f`` is a zero fraction. """
return dmp_zero_p(f.num, f.lev)
@property
def is_one(f):
"""Returns ``True`` if ``f`` is a unit fraction. """
return dmp_one_p(f.num, f.lev, f.dom) and \
dmp_one_p(f.den, f.lev, f.dom)
def __neg__(f):
return f.neg()
def __add__(f, g):
if isinstance(g, (DMP, DMF)):
return f.add(g)
elif g in f.dom:
return f.add_ground(f.dom.convert(g))
try:
return f.add(f.half_per(g))
except (TypeError, CoercionFailed, NotImplementedError):
return NotImplemented
def __radd__(f, g):
return f.__add__(g)
def __sub__(f, g):
if isinstance(g, (DMP, DMF)):
return f.sub(g)
try:
return f.sub(f.half_per(g))
except (TypeError, CoercionFailed, NotImplementedError):
return NotImplemented
def __rsub__(f, g):
return (-f).__add__(g)
def __mul__(f, g):
if isinstance(g, (DMP, DMF)):
return f.mul(g)
try:
return f.mul(f.half_per(g))
except (TypeError, CoercionFailed, NotImplementedError):
return NotImplemented
def __rmul__(f, g):
return f.__mul__(g)
def __pow__(f, n):
return f.pow(n)
def __truediv__(f, g):
if isinstance(g, (DMP, DMF)):
return f.quo(g)
try:
return f.quo(f.half_per(g))
except (TypeError, CoercionFailed, NotImplementedError):
return NotImplemented
def __rtruediv__(self, g):
return self.invert(check=False)*g
def __eq__(f, g):
try:
if isinstance(g, DMP):
_, _, _, (F_num, F_den), G = f.poly_unify(g)
if f.lev == g.lev:
return dmp_one_p(F_den, f.lev, f.dom) and F_num == G
else:
_, _, _, F, G = f.frac_unify(g)
if f.lev == g.lev:
return F == G
except UnificationFailed:
pass
return False
def __ne__(f, g):
try:
if isinstance(g, DMP):
_, _, _, (F_num, F_den), G = f.poly_unify(g)
if f.lev == g.lev:
return not (dmp_one_p(F_den, f.lev, f.dom) and F_num == G)
else:
_, _, _, F, G = f.frac_unify(g)
if f.lev == g.lev:
return F != G
except UnificationFailed:
pass
return True
def __lt__(f, g):
_, _, _, F, G = f.frac_unify(g)
return F < G
def __le__(f, g):
_, _, _, F, G = f.frac_unify(g)
return F <= G
def __gt__(f, g):
_, _, _, F, G = f.frac_unify(g)
return F > G
def __ge__(f, g):
_, _, _, F, G = f.frac_unify(g)
return F >= G
def __bool__(f):
return not dmp_zero_p(f.num, f.lev)
def init_normal_ANP(rep, mod, dom):
return ANP(dup_normal(rep, dom),
dup_normal(mod, dom), dom)
class ANP(CantSympify):
"""Dense Algebraic Number Polynomials over a field. """
__slots__ = ('_rep', '_mod', 'dom')
def __new__(cls, rep, mod, dom):
if isinstance(rep, DMP):
pass
elif type(rep) is dict: # don't use isinstance
rep = DMP(dup_from_dict(rep, dom), dom, 0)
else:
if isinstance(rep, list):
rep = [dom.convert(a) for a in rep]
else:
rep = [dom.convert(rep)]
rep = DMP(dup_strip(rep), dom, 0)
if isinstance(mod, DMP):
pass
elif isinstance(mod, dict):
mod = DMP(dup_from_dict(mod, dom), dom, 0)
else:
mod = DMP(dup_strip(mod), dom, 0)
return cls.new(rep, mod, dom)
@classmethod
def new(cls, rep, mod, dom):
if not (rep.dom == mod.dom == dom):
raise RuntimeError("Inconsistent domain")
obj = super().__new__(cls)
obj._rep = rep
obj._mod = mod
obj.dom = dom
return obj
# XXX: It should be possible to use __getnewargs__ rather than __reduce__
# but it doesn't work for some reason. Probably this would be easier if
# python-flint supported pickling for polynomial types.
def __reduce__(self):
return ANP, (self.rep, self.mod, self.dom)
@property
def rep(self):
return self._rep.to_list()
@property
def mod(self):
return self.mod_to_list()
def to_DMP(self):
return self._rep
def mod_to_DMP(self):
return self._mod
def per(f, rep):
return f.new(rep, f._mod, f.dom)
def __repr__(f):
return "%s(%s, %s, %s)" % (f.__class__.__name__, f._rep.to_list(), f._mod.to_list(), f.dom)
def __hash__(f):
return hash((f.__class__.__name__, f.to_tuple(), f._mod.to_tuple(), f.dom))
def convert(f, dom):
"""Convert ``f`` to a ``ANP`` over a new domain. """
if f.dom == dom:
return f
else:
return f.new(f._rep.convert(dom), f._mod.convert(dom), dom)
def unify(f, g):
"""Unify representations of two algebraic numbers. """
# XXX: This unify method is not used any more because unify_ANP is used
# instead.
if not isinstance(g, ANP) or f.mod != g.mod:
raise UnificationFailed("Cannot unify %s with %s" % (f, g))
if f.dom == g.dom:
return f.dom, f.per, f.rep, g.rep, f.mod
else:
dom = f.dom.unify(g.dom)
F = dup_convert(f.rep, f.dom, dom)
G = dup_convert(g.rep, g.dom, dom)
if dom != f.dom and dom != g.dom:
mod = dup_convert(f.mod, f.dom, dom)
else:
if dom == f.dom:
mod = f.mod
else:
mod = g.mod
per = lambda rep: ANP(rep, mod, dom)
return dom, per, F, G, mod
def unify_ANP(f, g):
"""Unify and return ``DMP`` instances of ``f`` and ``g``. """
if not isinstance(g, ANP) or f._mod != g._mod:
raise UnificationFailed("Cannot unify %s with %s" % (f, g))
# The domain is almost always QQ but there are some tests involving ZZ
if f.dom != g.dom:
dom = f.dom.unify(g.dom)
f = f.convert(dom)
g = g.convert(dom)
return f._rep, g._rep, f._mod, f.dom
@classmethod
def zero(cls, mod, dom):
return ANP(0, mod, dom)
@classmethod
def one(cls, mod, dom):
return ANP(1, mod, dom)
def to_dict(f):
"""Convert ``f`` to a dict representation with native coefficients. """
return f._rep.to_dict()
def to_sympy_dict(f):
"""Convert ``f`` to a dict representation with SymPy coefficients. """
rep = dmp_to_dict(f.rep, 0, f.dom)
for k, v in rep.items():
rep[k] = f.dom.to_sympy(v)
return rep
def to_list(f):
"""Convert ``f`` to a list representation with native coefficients. """
return f._rep.to_list()
def mod_to_list(f):
"""Return ``f.mod`` as a list with native coefficients. """
return f._mod.to_list()
def to_sympy_list(f):
"""Convert ``f`` to a list representation with SymPy coefficients. """
return [ f.dom.to_sympy(c) for c in f.to_list() ]
def to_tuple(f):
"""
Convert ``f`` to a tuple representation with native coefficients.
This is needed for hashing.
"""
return f._rep.to_tuple()
@classmethod
def from_list(cls, rep, mod, dom):
return ANP(dup_strip(list(map(dom.convert, rep))), mod, dom)
def add_ground(f, c):
"""Add an element of the ground domain to ``f``. """
return f.per(f._rep.add_ground(c))
def sub_ground(f, c):
"""Subtract an element of the ground domain from ``f``. """
return f.per(f._rep.sub_ground(c))
def mul_ground(f, c):
"""Multiply ``f`` by an element of the ground domain. """
return f.per(f._rep.mul_ground(c))
def quo_ground(f, c):
"""Quotient of ``f`` by an element of the ground domain. """
return f.per(f._rep.quo_ground(c))
def neg(f):
return f.per(f._rep.neg())
def add(f, g):
F, G, mod, dom = f.unify_ANP(g)
return f.new(F.add(G), mod, dom)
def sub(f, g):
F, G, mod, dom = f.unify_ANP(g)
return f.new(F.sub(G), mod, dom)
def mul(f, g):
F, G, mod, dom = f.unify_ANP(g)
return f.new(F.mul(G).rem(mod), mod, dom)
def pow(f, n):
"""Raise ``f`` to a non-negative power ``n``. """
if not isinstance(n, int):
raise TypeError("``int`` expected, got %s" % type(n))
mod = f._mod
F = f._rep
if n < 0:
F, n = F.invert(mod), -n
# XXX: Need a pow_mod method for DMP
return f.new(F.pow(n).rem(f._mod), mod, f.dom)
def exquo(f, g):
F, G, mod, dom = f.unify_ANP(g)
return f.new(F.mul(G.invert(mod)).rem(mod), mod, dom)
def div(f, g):
return f.exquo(g), f.zero(f._mod, f.dom)
def quo(f, g):
return f.exquo(g)
def rem(f, g):
F, G, mod, dom = f.unify_ANP(g)
s, h = F.half_gcdex(G)
if h.is_one:
return f.zero(mod, dom)
else:
raise NotInvertible("zero divisor")
def LC(f):
"""Returns the leading coefficient of ``f``. """
return f._rep.LC()
def TC(f):
"""Returns the trailing coefficient of ``f``. """
return f._rep.TC()
@property
def is_zero(f):
"""Returns ``True`` if ``f`` is a zero algebraic number. """
return f._rep.is_zero
@property
def is_one(f):
"""Returns ``True`` if ``f`` is a unit algebraic number. """
return f._rep.is_one
@property
def is_ground(f):
"""Returns ``True`` if ``f`` is an element of the ground domain. """
return f._rep.is_ground
def __pos__(f):
return f
def __neg__(f):
return f.neg()
def __add__(f, g):
if isinstance(g, ANP):
return f.add(g)
try:
g = f.dom.convert(g)
except CoercionFailed:
return NotImplemented
else:
return f.add_ground(g)
def __radd__(f, g):
return f.__add__(g)
def __sub__(f, g):
if isinstance(g, ANP):
return f.sub(g)
try:
g = f.dom.convert(g)
except CoercionFailed:
return NotImplemented
else:
return f.sub_ground(g)
def __rsub__(f, g):
return (-f).__add__(g)
def __mul__(f, g):
if isinstance(g, ANP):
return f.mul(g)
try:
g = f.dom.convert(g)
except CoercionFailed:
return NotImplemented
else:
return f.mul_ground(g)
def __rmul__(f, g):
return f.__mul__(g)
def __pow__(f, n):
return f.pow(n)
def __divmod__(f, g):
return f.div(g)
def __mod__(f, g):
return f.rem(g)
def __truediv__(f, g):
if isinstance(g, ANP):
return f.quo(g)
try:
g = f.dom.convert(g)
except CoercionFailed:
return NotImplemented
else:
return f.quo_ground(g)
def __eq__(f, g):
try:
F, G, _, _ = f.unify_ANP(g)
except UnificationFailed:
return NotImplemented
return F == G
def __ne__(f, g):
try:
F, G, _, _ = f.unify_ANP(g)
except UnificationFailed:
return NotImplemented
return F != G
def __lt__(f, g):
F, G, _, _ = f.unify_ANP(g)
return F < G
def __le__(f, g):
F, G, _, _ = f.unify_ANP(g)
return F <= G
def __gt__(f, g):
F, G, _, _ = f.unify_ANP(g)
return F > G
def __ge__(f, g):
F, G, _, _ = f.unify_ANP(g)
return F >= G
def __bool__(f):
return bool(f._rep)
PK ]ZZZ
���> > sympy/polys/polyconfig.py"""Configuration utilities for polynomial manipulation algorithms. """
from contextlib import contextmanager
_default_config = {
'USE_COLLINS_RESULTANT': False,
'USE_SIMPLIFY_GCD': True,
'USE_HEU_GCD': True,
'USE_IRREDUCIBLE_IN_FACTOR': False,
'USE_CYCLOTOMIC_FACTOR': True,
'EEZ_RESTART_IF_NEEDED': True,
'EEZ_NUMBER_OF_CONFIGS': 3,
'EEZ_NUMBER_OF_TRIES': 5,
'EEZ_MODULUS_STEP': 2,
'GF_IRRED_METHOD': 'rabin',
'GF_FACTOR_METHOD': 'zassenhaus',
'GROEBNER': 'buchberger',
}
_current_config = {}
@contextmanager
def using(**kwargs):
for k, v in kwargs.items():
setup(k, v)
yield
for k in kwargs.keys():
setup(k)
def setup(key, value=None):
"""Assign a value to (or reset) a configuration item. """
key = key.upper()
if value is not None:
_current_config[key] = value
else:
_current_config[key] = _default_config[key]
def query(key):
"""Ask for a value of the given configuration item. """
return _current_config.get(key.upper(), None)
def configure():
"""Initialized configuration of polys module. """
from os import getenv
for key, default in _default_config.items():
value = getenv('SYMPY_' + key)
if value is not None:
try:
_current_config[key] = eval(value)
except NameError:
_current_config[key] = value
else:
_current_config[key] = default
configure()
PK ]ZZZ��� � sympy/polys/polyerrors.py"""Definitions of common exceptions for `polys` module. """
from sympy.utilities import public
@public
class BasePolynomialError(Exception):
"""Base class for polynomial related exceptions. """
def new(self, *args):
raise NotImplementedError("abstract base class")
@public
class ExactQuotientFailed(BasePolynomialError):
def __init__(self, f, g, dom=None):
self.f, self.g, self.dom = f, g, dom
def __str__(self): # pragma: no cover
from sympy.printing.str import sstr
if self.dom is None:
return "%s does not divide %s" % (sstr(self.g), sstr(self.f))
else:
return "%s does not divide %s in %s" % (sstr(self.g), sstr(self.f), sstr(self.dom))
def new(self, f, g):
return self.__class__(f, g, self.dom)
@public
class PolynomialDivisionFailed(BasePolynomialError):
def __init__(self, f, g, domain):
self.f = f
self.g = g
self.domain = domain
def __str__(self):
if self.domain.is_EX:
msg = "You may want to use a different simplification algorithm. Note " \
"that in general it's not possible to guarantee to detect zero " \
"in this domain."
elif not self.domain.is_Exact:
msg = "Your working precision or tolerance of computations may be set " \
"improperly. Adjust those parameters of the coefficient domain " \
"and try again."
else:
msg = "Zero detection is guaranteed in this coefficient domain. This " \
"may indicate a bug in SymPy or the domain is user defined and " \
"doesn't implement zero detection properly."
return "couldn't reduce degree in a polynomial division algorithm when " \
"dividing %s by %s. This can happen when it's not possible to " \
"detect zero in the coefficient domain. The domain of computation " \
"is %s. %s" % (self.f, self.g, self.domain, msg)
@public
class OperationNotSupported(BasePolynomialError):
def __init__(self, poly, func):
self.poly = poly
self.func = func
def __str__(self): # pragma: no cover
return "`%s` operation not supported by %s representation" % (self.func, self.poly.rep.__class__.__name__)
@public
class HeuristicGCDFailed(BasePolynomialError):
pass
class ModularGCDFailed(BasePolynomialError):
pass
@public
class HomomorphismFailed(BasePolynomialError):
pass
@public
class IsomorphismFailed(BasePolynomialError):
pass
@public
class ExtraneousFactors(BasePolynomialError):
pass
@public
class EvaluationFailed(BasePolynomialError):
pass
@public
class RefinementFailed(BasePolynomialError):
pass
@public
class CoercionFailed(BasePolynomialError):
pass
@public
class NotInvertible(BasePolynomialError):
pass
@public
class NotReversible(BasePolynomialError):
pass
@public
class NotAlgebraic(BasePolynomialError):
pass
@public
class DomainError(BasePolynomialError):
pass
@public
class PolynomialError(BasePolynomialError):
pass
@public
class UnificationFailed(BasePolynomialError):
pass
@public
class UnsolvableFactorError(BasePolynomialError):
"""Raised if ``roots`` is called with strict=True and a polynomial
having a factor whose solutions are not expressible in radicals
is encountered."""
@public
class GeneratorsError(BasePolynomialError):
pass
@public
class GeneratorsNeeded(GeneratorsError):
pass
@public
class ComputationFailed(BasePolynomialError):
def __init__(self, func, nargs, exc):
self.func = func
self.nargs = nargs
self.exc = exc
def __str__(self):
return "%s(%s) failed without generators" % (self.func, ', '.join(map(str, self.exc.exprs[:self.nargs])))
@public
class UnivariatePolynomialError(PolynomialError):
pass
@public
class MultivariatePolynomialError(PolynomialError):
pass
@public
class PolificationFailed(PolynomialError):
def __init__(self, opt, origs, exprs, seq=False):
if not seq:
self.orig = origs
self.expr = exprs
self.origs = [origs]
self.exprs = [exprs]
else:
self.origs = origs
self.exprs = exprs
self.opt = opt
self.seq = seq
def __str__(self): # pragma: no cover
if not self.seq:
return "Cannot construct a polynomial from %s" % str(self.orig)
else:
return "Cannot construct polynomials from %s" % ', '.join(map(str, self.origs))
@public
class OptionError(BasePolynomialError):
pass
@public
class FlagError(OptionError):
pass
PK ]ZZZ�ڀ�c! c! sympy/polys/polyfuncs.py"""High-level polynomials manipulation functions. """
from sympy.core import S, Basic, symbols, Dummy
from sympy.polys.polyerrors import (
PolificationFailed, ComputationFailed,
MultivariatePolynomialError, OptionError)
from sympy.polys.polyoptions import allowed_flags, build_options
from sympy.polys.polytools import poly_from_expr, Poly
from sympy.polys.specialpolys import (
symmetric_poly, interpolating_poly)
from sympy.polys.rings import sring
from sympy.utilities import numbered_symbols, take, public
@public
def symmetrize(F, *gens, **args):
r"""
Rewrite a polynomial in terms of elementary symmetric polynomials.
A symmetric polynomial is a multivariate polynomial that remains invariant
under any variable permutation, i.e., if `f = f(x_1, x_2, \dots, x_n)`,
then `f = f(x_{i_1}, x_{i_2}, \dots, x_{i_n})`, where
`(i_1, i_2, \dots, i_n)` is a permutation of `(1, 2, \dots, n)` (an
element of the group `S_n`).
Returns a tuple of symmetric polynomials ``(f1, f2, ..., fn)`` such that
``f = f1 + f2 + ... + fn``.
Examples
========
>>> from sympy.polys.polyfuncs import symmetrize
>>> from sympy.abc import x, y
>>> symmetrize(x**2 + y**2)
(-2*x*y + (x + y)**2, 0)
>>> symmetrize(x**2 + y**2, formal=True)
(s1**2 - 2*s2, 0, [(s1, x + y), (s2, x*y)])
>>> symmetrize(x**2 - y**2)
(-2*x*y + (x + y)**2, -2*y**2)
>>> symmetrize(x**2 - y**2, formal=True)
(s1**2 - 2*s2, -2*y**2, [(s1, x + y), (s2, x*y)])
"""
allowed_flags(args, ['formal', 'symbols'])
iterable = True
if not hasattr(F, '__iter__'):
iterable = False
F = [F]
R, F = sring(F, *gens, **args)
gens = R.symbols
opt = build_options(gens, args)
symbols = opt.symbols
symbols = [next(symbols) for i in range(len(gens))]
result = []
for f in F:
p, r, m = f.symmetrize()
result.append((p.as_expr(*symbols), r.as_expr(*gens)))
polys = [(s, g.as_expr()) for s, (_, g) in zip(symbols, m)]
if not opt.formal:
for i, (sym, non_sym) in enumerate(result):
result[i] = (sym.subs(polys), non_sym)
if not iterable:
result, = result
if not opt.formal:
return result
else:
if iterable:
return result, polys
else:
return result + (polys,)
@public
def horner(f, *gens, **args):
"""
Rewrite a polynomial in Horner form.
Among other applications, evaluation of a polynomial at a point is optimal
when it is applied using the Horner scheme ([1]).
Examples
========
>>> from sympy.polys.polyfuncs import horner
>>> from sympy.abc import x, y, a, b, c, d, e
>>> horner(9*x**4 + 8*x**3 + 7*x**2 + 6*x + 5)
x*(x*(x*(9*x + 8) + 7) + 6) + 5
>>> horner(a*x**4 + b*x**3 + c*x**2 + d*x + e)
e + x*(d + x*(c + x*(a*x + b)))
>>> f = 4*x**2*y**2 + 2*x**2*y + 2*x*y**2 + x*y
>>> horner(f, wrt=x)
x*(x*y*(4*y + 2) + y*(2*y + 1))
>>> horner(f, wrt=y)
y*(x*y*(4*x + 2) + x*(2*x + 1))
References
==========
[1] - https://en.wikipedia.org/wiki/Horner_scheme
"""
allowed_flags(args, [])
try:
F, opt = poly_from_expr(f, *gens, **args)
except PolificationFailed as exc:
return exc.expr
form, gen = S.Zero, F.gen
if F.is_univariate:
for coeff in F.all_coeffs():
form = form*gen + coeff
else:
F, gens = Poly(F, gen), gens[1:]
for coeff in F.all_coeffs():
form = form*gen + horner(coeff, *gens, **args)
return form
@public
def interpolate(data, x):
"""
Construct an interpolating polynomial for the data points
evaluated at point x (which can be symbolic or numeric).
Examples
========
>>> from sympy.polys.polyfuncs import interpolate
>>> from sympy.abc import a, b, x
A list is interpreted as though it were paired with a range starting
from 1:
>>> interpolate([1, 4, 9, 16], x)
x**2
This can be made explicit by giving a list of coordinates:
>>> interpolate([(1, 1), (2, 4), (3, 9)], x)
x**2
The (x, y) coordinates can also be given as keys and values of a
dictionary (and the points need not be equispaced):
>>> interpolate([(-1, 2), (1, 2), (2, 5)], x)
x**2 + 1
>>> interpolate({-1: 2, 1: 2, 2: 5}, x)
x**2 + 1
If the interpolation is going to be used only once then the
value of interest can be passed instead of passing a symbol:
>>> interpolate([1, 4, 9], 5)
25
Symbolic coordinates are also supported:
>>> [(i,interpolate((a, b), i)) for i in range(1, 4)]
[(1, a), (2, b), (3, -a + 2*b)]
"""
n = len(data)
if isinstance(data, dict):
if x in data:
return S(data[x])
X, Y = list(zip(*data.items()))
else:
if isinstance(data[0], tuple):
X, Y = list(zip(*data))
if x in X:
return S(Y[X.index(x)])
else:
if x in range(1, n + 1):
return S(data[x - 1])
Y = list(data)
X = list(range(1, n + 1))
try:
return interpolating_poly(n, x, X, Y).expand()
except ValueError:
d = Dummy()
return interpolating_poly(n, d, X, Y).expand().subs(d, x)
@public
def rational_interpolate(data, degnum, X=symbols('x')):
"""
Returns a rational interpolation, where the data points are element of
any integral domain.
The first argument contains the data (as a list of coordinates). The
``degnum`` argument is the degree in the numerator of the rational
function. Setting it too high will decrease the maximal degree in the
denominator for the same amount of data.
Examples
========
>>> from sympy.polys.polyfuncs import rational_interpolate
>>> data = [(1, -210), (2, -35), (3, 105), (4, 231), (5, 350), (6, 465)]
>>> rational_interpolate(data, 2)
(105*x**2 - 525)/(x + 1)
Values do not need to be integers:
>>> from sympy import sympify
>>> x = [1, 2, 3, 4, 5, 6]
>>> y = sympify("[-1, 0, 2, 22/5, 7, 68/7]")
>>> rational_interpolate(zip(x, y), 2)
(3*x**2 - 7*x + 2)/(x + 1)
The symbol for the variable can be changed if needed:
>>> from sympy import symbols
>>> z = symbols('z')
>>> rational_interpolate(data, 2, X=z)
(105*z**2 - 525)/(z + 1)
References
==========
.. [1] Algorithm is adapted from:
http://axiom-wiki.newsynthesis.org/RationalInterpolation
"""
from sympy.matrices.dense import ones
xdata, ydata = list(zip(*data))
k = len(xdata) - degnum - 1
if k < 0:
raise OptionError("Too few values for the required degree.")
c = ones(degnum + k + 1, degnum + k + 2)
for j in range(max(degnum, k)):
for i in range(degnum + k + 1):
c[i, j + 1] = c[i, j]*xdata[i]
for j in range(k + 1):
for i in range(degnum + k + 1):
c[i, degnum + k + 1 - j] = -c[i, k - j]*ydata[i]
r = c.nullspace()[0]
return (sum(r[i] * X**i for i in range(degnum + 1))
/ sum(r[i + degnum + 1] * X**i for i in range(k + 1)))
@public
def viete(f, roots=None, *gens, **args):
"""
Generate Viete's formulas for ``f``.
Examples
========
>>> from sympy.polys.polyfuncs import viete
>>> from sympy import symbols
>>> x, a, b, c, r1, r2 = symbols('x,a:c,r1:3')
>>> viete(a*x**2 + b*x + c, [r1, r2], x)
[(r1 + r2, -b/a), (r1*r2, c/a)]
"""
allowed_flags(args, [])
if isinstance(roots, Basic):
gens, roots = (roots,) + gens, None
try:
f, opt = poly_from_expr(f, *gens, **args)
except PolificationFailed as exc:
raise ComputationFailed('viete', 1, exc)
if f.is_multivariate:
raise MultivariatePolynomialError(
"multivariate polynomials are not allowed")
n = f.degree()
if n < 1:
raise ValueError(
"Cannot derive Viete's formulas for a constant polynomial")
if roots is None:
roots = numbered_symbols('r', start=1)
roots = take(roots, n)
if n != len(roots):
raise ValueError("required %s roots, got %s" % (n, len(roots)))
lc, coeffs = f.LC(), f.all_coeffs()
result, sign = [], -1
for i, coeff in enumerate(coeffs[1:]):
poly = symmetric_poly(i + 1, roots)
coeff = sign*(coeff/lc)
result.append((poly, coeff))
sign = -sign
return result
PK ]ZZZ����+& +& sympy/polys/polymatrix.pyfrom sympy.core.expr import Expr
from sympy.core.symbol import Dummy
from sympy.core.sympify import _sympify
from sympy.polys.polyerrors import CoercionFailed
from sympy.polys.polytools import Poly, parallel_poly_from_expr
from sympy.polys.domains import QQ
from sympy.polys.matrices import DomainMatrix
from sympy.polys.matrices.domainscalar import DomainScalar
class MutablePolyDenseMatrix:
"""
A mutable matrix of objects from poly module or to operate with them.
Examples
========
>>> from sympy.polys.polymatrix import PolyMatrix
>>> from sympy import Symbol, Poly
>>> x = Symbol('x')
>>> pm1 = PolyMatrix([[Poly(x**2, x), Poly(-x, x)], [Poly(x**3, x), Poly(-1 + x, x)]])
>>> v1 = PolyMatrix([[1, 0], [-1, 0]], x)
>>> pm1*v1
PolyMatrix([
[ x**2 + x, 0],
[x**3 - x + 1, 0]], ring=QQ[x])
>>> pm1.ring
ZZ[x]
>>> v1*pm1
PolyMatrix([
[ x**2, -x],
[-x**2, x]], ring=QQ[x])
>>> pm2 = PolyMatrix([[Poly(x**2, x, domain='QQ'), Poly(0, x, domain='QQ'), Poly(1, x, domain='QQ'), \
Poly(x**3, x, domain='QQ'), Poly(0, x, domain='QQ'), Poly(-x**3, x, domain='QQ')]])
>>> v2 = PolyMatrix([1, 0, 0, 0, 0, 0], x)
>>> v2.ring
QQ[x]
>>> pm2*v2
PolyMatrix([[x**2]], ring=QQ[x])
"""
def __new__(cls, *args, ring=None):
if not args:
# PolyMatrix(ring=QQ[x])
if ring is None:
raise TypeError("The ring needs to be specified for an empty PolyMatrix")
rows, cols, items, gens = 0, 0, [], ()
elif isinstance(args[0], list):
elements, gens = args[0], args[1:]
if not elements:
# PolyMatrix([])
rows, cols, items = 0, 0, []
elif isinstance(elements[0], (list, tuple)):
# PolyMatrix([[1, 2]], x)
rows, cols = len(elements), len(elements[0])
items = [e for row in elements for e in row]
else:
# PolyMatrix([1, 2], x)
rows, cols = len(elements), 1
items = elements
elif [type(a) for a in args[:3]] == [int, int, list]:
# PolyMatrix(2, 2, [1, 2, 3, 4], x)
rows, cols, items, gens = args[0], args[1], args[2], args[3:]
elif [type(a) for a in args[:3]] == [int, int, type(lambda: 0)]:
# PolyMatrix(2, 2, lambda i, j: i+j, x)
rows, cols, func, gens = args[0], args[1], args[2], args[3:]
items = [func(i, j) for i in range(rows) for j in range(cols)]
else:
raise TypeError("Invalid arguments")
# PolyMatrix([[1]], x, y) vs PolyMatrix([[1]], (x, y))
if len(gens) == 1 and isinstance(gens[0], tuple):
gens = gens[0]
# gens is now a tuple (x, y)
return cls.from_list(rows, cols, items, gens, ring)
@classmethod
def from_list(cls, rows, cols, items, gens, ring):
# items can be Expr, Poly, or a mix of Expr and Poly
items = [_sympify(item) for item in items]
if items and all(isinstance(item, Poly) for item in items):
polys = True
else:
polys = False
# Identify the ring for the polys
if ring is not None:
# Parse a domain string like 'QQ[x]'
if isinstance(ring, str):
ring = Poly(0, Dummy(), domain=ring).domain
elif polys:
p = items[0]
for p2 in items[1:]:
p, _ = p.unify(p2)
ring = p.domain[p.gens]
else:
items, info = parallel_poly_from_expr(items, gens, field=True)
ring = info['domain'][info['gens']]
polys = True
# Efficiently convert when all elements are Poly
if polys:
p_ring = Poly(0, ring.symbols, domain=ring.domain)
to_ring = ring.ring.from_list
convert_poly = lambda p: to_ring(p.unify(p_ring)[0].rep.to_list())
elements = [convert_poly(p) for p in items]
else:
convert_expr = ring.from_sympy
elements = [convert_expr(e.as_expr()) for e in items]
# Convert to domain elements and construct DomainMatrix
elements_lol = [[elements[i*cols + j] for j in range(cols)] for i in range(rows)]
dm = DomainMatrix(elements_lol, (rows, cols), ring)
return cls.from_dm(dm)
@classmethod
def from_dm(cls, dm):
obj = super().__new__(cls)
dm = dm.to_sparse()
R = dm.domain
obj._dm = dm
obj.ring = R
obj.domain = R.domain
obj.gens = R.symbols
return obj
def to_Matrix(self):
return self._dm.to_Matrix()
@classmethod
def from_Matrix(cls, other, *gens, ring=None):
return cls(*other.shape, other.flat(), *gens, ring=ring)
def set_gens(self, gens):
return self.from_Matrix(self.to_Matrix(), gens)
def __repr__(self):
if self.rows * self.cols:
return 'Poly' + repr(self.to_Matrix())[:-1] + f', ring={self.ring})'
else:
return f'PolyMatrix({self.rows}, {self.cols}, [], ring={self.ring})'
@property
def shape(self):
return self._dm.shape
@property
def rows(self):
return self.shape[0]
@property
def cols(self):
return self.shape[1]
def __len__(self):
return self.rows * self.cols
def __getitem__(self, key):
def to_poly(v):
ground = self._dm.domain.domain
gens = self._dm.domain.symbols
return Poly(v.to_dict(), gens, domain=ground)
dm = self._dm
if isinstance(key, slice):
items = dm.flat()[key]
return [to_poly(item) for item in items]
elif isinstance(key, int):
i, j = divmod(key, self.cols)
e = dm[i,j]
return to_poly(e.element)
i, j = key
if isinstance(i, int) and isinstance(j, int):
return to_poly(dm[i, j].element)
else:
return self.from_dm(dm[i, j])
def __eq__(self, other):
if not isinstance(self, type(other)):
return NotImplemented
return self._dm == other._dm
def __add__(self, other):
if isinstance(other, type(self)):
return self.from_dm(self._dm + other._dm)
return NotImplemented
def __sub__(self, other):
if isinstance(other, type(self)):
return self.from_dm(self._dm - other._dm)
return NotImplemented
def __mul__(self, other):
if isinstance(other, type(self)):
return self.from_dm(self._dm * other._dm)
elif isinstance(other, int):
other = _sympify(other)
if isinstance(other, Expr):
Kx = self.ring
try:
other_ds = DomainScalar(Kx.from_sympy(other), Kx)
except (CoercionFailed, ValueError):
other_ds = DomainScalar.from_sympy(other)
return self.from_dm(self._dm * other_ds)
return NotImplemented
def __rmul__(self, other):
if isinstance(other, int):
other = _sympify(other)
if isinstance(other, Expr):
other_ds = DomainScalar.from_sympy(other)
return self.from_dm(other_ds * self._dm)
return NotImplemented
def __truediv__(self, other):
if isinstance(other, Poly):
other = other.as_expr()
elif isinstance(other, int):
other = _sympify(other)
if not isinstance(other, Expr):
return NotImplemented
other = self.domain.from_sympy(other)
inverse = self.ring.convert_from(1/other, self.domain)
inverse = DomainScalar(inverse, self.ring)
dm = self._dm * inverse
return self.from_dm(dm)
def __neg__(self):
return self.from_dm(-self._dm)
def transpose(self):
return self.from_dm(self._dm.transpose())
def row_join(self, other):
dm = DomainMatrix.hstack(self._dm, other._dm)
return self.from_dm(dm)
def col_join(self, other):
dm = DomainMatrix.vstack(self._dm, other._dm)
return self.from_dm(dm)
def applyfunc(self, func):
M = self.to_Matrix().applyfunc(func)
return self.from_Matrix(M, self.gens)
@classmethod
def eye(cls, n, gens):
return cls.from_dm(DomainMatrix.eye(n, QQ[gens]))
@classmethod
def zeros(cls, m, n, gens):
return cls.from_dm(DomainMatrix.zeros((m, n), QQ[gens]))
def rref(self, simplify='ignore', normalize_last='ignore'):
# If this is K[x] then computes RREF in ground field K.
if not (self.domain.is_Field and all(p.is_ground for p in self)):
raise ValueError("PolyMatrix rref is only for ground field elements")
dm = self._dm
dm_ground = dm.convert_to(dm.domain.domain)
dm_rref, pivots = dm_ground.rref()
dm_rref = dm_rref.convert_to(dm.domain)
return self.from_dm(dm_rref), pivots
def nullspace(self):
# If this is K[x] then computes nullspace in ground field K.
if not (self.domain.is_Field and all(p.is_ground for p in self)):
raise ValueError("PolyMatrix nullspace is only for ground field elements")
dm = self._dm
K, Kx = self.domain, self.ring
dm_null_rows = dm.convert_to(K).nullspace(divide_last=True).convert_to(Kx)
dm_null = dm_null_rows.transpose()
dm_basis = [dm_null[:,i] for i in range(dm_null.shape[1])]
return [self.from_dm(dmvec) for dmvec in dm_basis]
def rank(self):
return self.cols - len(self.nullspace())
MutablePolyMatrix = PolyMatrix = MutablePolyDenseMatrix
PK ]ZZZ��>$�T �T sympy/polys/polyoptions.py"""Options manager for :class:`~.Poly` and public API functions. """
from __future__ import annotations
__all__ = ["Options"]
from sympy.core import Basic, sympify
from sympy.polys.polyerrors import GeneratorsError, OptionError, FlagError
from sympy.utilities import numbered_symbols, topological_sort, public
from sympy.utilities.iterables import has_dups, is_sequence
import sympy.polys
import re
class Option:
"""Base class for all kinds of options. """
option: str | None = None
is_Flag = False
requires: list[str] = []
excludes: list[str] = []
after: list[str] = []
before: list[str] = []
@classmethod
def default(cls):
return None
@classmethod
def preprocess(cls, option):
return None
@classmethod
def postprocess(cls, options):
pass
class Flag(Option):
"""Base class for all kinds of flags. """
is_Flag = True
class BooleanOption(Option):
"""An option that must have a boolean value or equivalent assigned. """
@classmethod
def preprocess(cls, value):
if value in [True, False]:
return bool(value)
else:
raise OptionError("'%s' must have a boolean value assigned, got %s" % (cls.option, value))
class OptionType(type):
"""Base type for all options that does registers options. """
def __init__(cls, *args, **kwargs):
@property
def getter(self):
try:
return self[cls.option]
except KeyError:
return cls.default()
setattr(Options, cls.option, getter)
Options.__options__[cls.option] = cls
@public
class Options(dict):
"""
Options manager for polynomial manipulation module.
Examples
========
>>> from sympy.polys.polyoptions import Options
>>> from sympy.polys.polyoptions import build_options
>>> from sympy.abc import x, y, z
>>> Options((x, y, z), {'domain': 'ZZ'})
{'auto': False, 'domain': ZZ, 'gens': (x, y, z)}
>>> build_options((x, y, z), {'domain': 'ZZ'})
{'auto': False, 'domain': ZZ, 'gens': (x, y, z)}
**Options**
* Expand --- boolean option
* Gens --- option
* Wrt --- option
* Sort --- option
* Order --- option
* Field --- boolean option
* Greedy --- boolean option
* Domain --- option
* Split --- boolean option
* Gaussian --- boolean option
* Extension --- option
* Modulus --- option
* Symmetric --- boolean option
* Strict --- boolean option
**Flags**
* Auto --- boolean flag
* Frac --- boolean flag
* Formal --- boolean flag
* Polys --- boolean flag
* Include --- boolean flag
* All --- boolean flag
* Gen --- flag
* Series --- boolean flag
"""
__order__ = None
__options__: dict[str, type[Option]] = {}
def __init__(self, gens, args, flags=None, strict=False):
dict.__init__(self)
if gens and args.get('gens', ()):
raise OptionError(
"both '*gens' and keyword argument 'gens' supplied")
elif gens:
args = dict(args)
args['gens'] = gens
defaults = args.pop('defaults', {})
def preprocess_options(args):
for option, value in args.items():
try:
cls = self.__options__[option]
except KeyError:
raise OptionError("'%s' is not a valid option" % option)
if issubclass(cls, Flag):
if flags is None or option not in flags:
if strict:
raise OptionError("'%s' flag is not allowed in this context" % option)
if value is not None:
self[option] = cls.preprocess(value)
preprocess_options(args)
for key in dict(defaults):
if key in self:
del defaults[key]
else:
for option in self.keys():
cls = self.__options__[option]
if key in cls.excludes:
del defaults[key]
break
preprocess_options(defaults)
for option in self.keys():
cls = self.__options__[option]
for require_option in cls.requires:
if self.get(require_option) is None:
raise OptionError("'%s' option is only allowed together with '%s'" % (option, require_option))
for exclude_option in cls.excludes:
if self.get(exclude_option) is not None:
raise OptionError("'%s' option is not allowed together with '%s'" % (option, exclude_option))
for option in self.__order__:
self.__options__[option].postprocess(self)
@classmethod
def _init_dependencies_order(cls):
"""Resolve the order of options' processing. """
if cls.__order__ is None:
vertices, edges = [], set()
for name, option in cls.__options__.items():
vertices.append(name)
edges.update((_name, name) for _name in option.after)
edges.update((name, _name) for _name in option.before)
try:
cls.__order__ = topological_sort((vertices, list(edges)))
except ValueError:
raise RuntimeError(
"cycle detected in sympy.polys options framework")
def clone(self, updates={}):
"""Clone ``self`` and update specified options. """
obj = dict.__new__(self.__class__)
for option, value in self.items():
obj[option] = value
for option, value in updates.items():
obj[option] = value
return obj
def __setattr__(self, attr, value):
if attr in self.__options__:
self[attr] = value
else:
super().__setattr__(attr, value)
@property
def args(self):
args = {}
for option, value in self.items():
if value is not None and option != 'gens':
cls = self.__options__[option]
if not issubclass(cls, Flag):
args[option] = value
return args
@property
def options(self):
options = {}
for option, cls in self.__options__.items():
if not issubclass(cls, Flag):
options[option] = getattr(self, option)
return options
@property
def flags(self):
flags = {}
for option, cls in self.__options__.items():
if issubclass(cls, Flag):
flags[option] = getattr(self, option)
return flags
class Expand(BooleanOption, metaclass=OptionType):
"""``expand`` option to polynomial manipulation functions. """
option = 'expand'
requires: list[str] = []
excludes: list[str] = []
@classmethod
def default(cls):
return True
class Gens(Option, metaclass=OptionType):
"""``gens`` option to polynomial manipulation functions. """
option = 'gens'
requires: list[str] = []
excludes: list[str] = []
@classmethod
def default(cls):
return ()
@classmethod
def preprocess(cls, gens):
if isinstance(gens, Basic):
gens = (gens,)
elif len(gens) == 1 and is_sequence(gens[0]):
gens = gens[0]
if gens == (None,):
gens = ()
elif has_dups(gens):
raise GeneratorsError("duplicated generators: %s" % str(gens))
elif any(gen.is_commutative is False for gen in gens):
raise GeneratorsError("non-commutative generators: %s" % str(gens))
return tuple(gens)
class Wrt(Option, metaclass=OptionType):
"""``wrt`` option to polynomial manipulation functions. """
option = 'wrt'
requires: list[str] = []
excludes: list[str] = []
_re_split = re.compile(r"\s*,\s*|\s+")
@classmethod
def preprocess(cls, wrt):
if isinstance(wrt, Basic):
return [str(wrt)]
elif isinstance(wrt, str):
wrt = wrt.strip()
if wrt.endswith(','):
raise OptionError('Bad input: missing parameter.')
if not wrt:
return []
return list(cls._re_split.split(wrt))
elif hasattr(wrt, '__getitem__'):
return list(map(str, wrt))
else:
raise OptionError("invalid argument for 'wrt' option")
class Sort(Option, metaclass=OptionType):
"""``sort`` option to polynomial manipulation functions. """
option = 'sort'
requires: list[str] = []
excludes: list[str] = []
@classmethod
def default(cls):
return []
@classmethod
def preprocess(cls, sort):
if isinstance(sort, str):
return [ gen.strip() for gen in sort.split('>') ]
elif hasattr(sort, '__getitem__'):
return list(map(str, sort))
else:
raise OptionError("invalid argument for 'sort' option")
class Order(Option, metaclass=OptionType):
"""``order`` option to polynomial manipulation functions. """
option = 'order'
requires: list[str] = []
excludes: list[str] = []
@classmethod
def default(cls):
return sympy.polys.orderings.lex
@classmethod
def preprocess(cls, order):
return sympy.polys.orderings.monomial_key(order)
class Field(BooleanOption, metaclass=OptionType):
"""``field`` option to polynomial manipulation functions. """
option = 'field'
requires: list[str] = []
excludes = ['domain', 'split', 'gaussian']
class Greedy(BooleanOption, metaclass=OptionType):
"""``greedy`` option to polynomial manipulation functions. """
option = 'greedy'
requires: list[str] = []
excludes = ['domain', 'split', 'gaussian', 'extension', 'modulus', 'symmetric']
class Composite(BooleanOption, metaclass=OptionType):
"""``composite`` option to polynomial manipulation functions. """
option = 'composite'
@classmethod
def default(cls):
return None
requires: list[str] = []
excludes = ['domain', 'split', 'gaussian', 'extension', 'modulus', 'symmetric']
class Domain(Option, metaclass=OptionType):
"""``domain`` option to polynomial manipulation functions. """
option = 'domain'
requires: list[str] = []
excludes = ['field', 'greedy', 'split', 'gaussian', 'extension']
after = ['gens']
_re_realfield = re.compile(r"^(R|RR)(_(\d+))?$")
_re_complexfield = re.compile(r"^(C|CC)(_(\d+))?$")
_re_finitefield = re.compile(r"^(FF|GF)\((\d+)\)$")
_re_polynomial = re.compile(r"^(Z|ZZ|Q|QQ|ZZ_I|QQ_I|R|RR|C|CC)\[(.+)\]$")
_re_fraction = re.compile(r"^(Z|ZZ|Q|QQ)\((.+)\)$")
_re_algebraic = re.compile(r"^(Q|QQ)\<(.+)\>$")
@classmethod
def preprocess(cls, domain):
if isinstance(domain, sympy.polys.domains.Domain):
return domain
elif hasattr(domain, 'to_domain'):
return domain.to_domain()
elif isinstance(domain, str):
if domain in ['Z', 'ZZ']:
return sympy.polys.domains.ZZ
if domain in ['Q', 'QQ']:
return sympy.polys.domains.QQ
if domain == 'ZZ_I':
return sympy.polys.domains.ZZ_I
if domain == 'QQ_I':
return sympy.polys.domains.QQ_I
if domain == 'EX':
return sympy.polys.domains.EX
r = cls._re_realfield.match(domain)
if r is not None:
_, _, prec = r.groups()
if prec is None:
return sympy.polys.domains.RR
else:
return sympy.polys.domains.RealField(int(prec))
r = cls._re_complexfield.match(domain)
if r is not None:
_, _, prec = r.groups()
if prec is None:
return sympy.polys.domains.CC
else:
return sympy.polys.domains.ComplexField(int(prec))
r = cls._re_finitefield.match(domain)
if r is not None:
return sympy.polys.domains.FF(int(r.groups()[1]))
r = cls._re_polynomial.match(domain)
if r is not None:
ground, gens = r.groups()
gens = list(map(sympify, gens.split(',')))
if ground in ['Z', 'ZZ']:
return sympy.polys.domains.ZZ.poly_ring(*gens)
elif ground in ['Q', 'QQ']:
return sympy.polys.domains.QQ.poly_ring(*gens)
elif ground in ['R', 'RR']:
return sympy.polys.domains.RR.poly_ring(*gens)
elif ground == 'ZZ_I':
return sympy.polys.domains.ZZ_I.poly_ring(*gens)
elif ground == 'QQ_I':
return sympy.polys.domains.QQ_I.poly_ring(*gens)
else:
return sympy.polys.domains.CC.poly_ring(*gens)
r = cls._re_fraction.match(domain)
if r is not None:
ground, gens = r.groups()
gens = list(map(sympify, gens.split(',')))
if ground in ['Z', 'ZZ']:
return sympy.polys.domains.ZZ.frac_field(*gens)
else:
return sympy.polys.domains.QQ.frac_field(*gens)
r = cls._re_algebraic.match(domain)
if r is not None:
gens = list(map(sympify, r.groups()[1].split(',')))
return sympy.polys.domains.QQ.algebraic_field(*gens)
raise OptionError('expected a valid domain specification, got %s' % domain)
@classmethod
def postprocess(cls, options):
if 'gens' in options and 'domain' in options and options['domain'].is_Composite and \
(set(options['domain'].symbols) & set(options['gens'])):
raise GeneratorsError(
"ground domain and generators interfere together")
elif ('gens' not in options or not options['gens']) and \
'domain' in options and options['domain'] == sympy.polys.domains.EX:
raise GeneratorsError("you have to provide generators because EX domain was requested")
class Split(BooleanOption, metaclass=OptionType):
"""``split`` option to polynomial manipulation functions. """
option = 'split'
requires: list[str] = []
excludes = ['field', 'greedy', 'domain', 'gaussian', 'extension',
'modulus', 'symmetric']
@classmethod
def postprocess(cls, options):
if 'split' in options:
raise NotImplementedError("'split' option is not implemented yet")
class Gaussian(BooleanOption, metaclass=OptionType):
"""``gaussian`` option to polynomial manipulation functions. """
option = 'gaussian'
requires: list[str] = []
excludes = ['field', 'greedy', 'domain', 'split', 'extension',
'modulus', 'symmetric']
@classmethod
def postprocess(cls, options):
if 'gaussian' in options and options['gaussian'] is True:
options['domain'] = sympy.polys.domains.QQ_I
Extension.postprocess(options)
class Extension(Option, metaclass=OptionType):
"""``extension`` option to polynomial manipulation functions. """
option = 'extension'
requires: list[str] = []
excludes = ['greedy', 'domain', 'split', 'gaussian', 'modulus',
'symmetric']
@classmethod
def preprocess(cls, extension):
if extension == 1:
return bool(extension)
elif extension == 0:
raise OptionError("'False' is an invalid argument for 'extension'")
else:
if not hasattr(extension, '__iter__'):
extension = {extension}
else:
if not extension:
extension = None
else:
extension = set(extension)
return extension
@classmethod
def postprocess(cls, options):
if 'extension' in options and options['extension'] is not True:
options['domain'] = sympy.polys.domains.QQ.algebraic_field(
*options['extension'])
class Modulus(Option, metaclass=OptionType):
"""``modulus`` option to polynomial manipulation functions. """
option = 'modulus'
requires: list[str] = []
excludes = ['greedy', 'split', 'domain', 'gaussian', 'extension']
@classmethod
def preprocess(cls, modulus):
modulus = sympify(modulus)
if modulus.is_Integer and modulus > 0:
return int(modulus)
else:
raise OptionError(
"'modulus' must a positive integer, got %s" % modulus)
@classmethod
def postprocess(cls, options):
if 'modulus' in options:
modulus = options['modulus']
symmetric = options.get('symmetric', True)
options['domain'] = sympy.polys.domains.FF(modulus, symmetric)
class Symmetric(BooleanOption, metaclass=OptionType):
"""``symmetric`` option to polynomial manipulation functions. """
option = 'symmetric'
requires = ['modulus']
excludes = ['greedy', 'domain', 'split', 'gaussian', 'extension']
class Strict(BooleanOption, metaclass=OptionType):
"""``strict`` option to polynomial manipulation functions. """
option = 'strict'
@classmethod
def default(cls):
return True
class Auto(BooleanOption, Flag, metaclass=OptionType):
"""``auto`` flag to polynomial manipulation functions. """
option = 'auto'
after = ['field', 'domain', 'extension', 'gaussian']
@classmethod
def default(cls):
return True
@classmethod
def postprocess(cls, options):
if ('domain' in options or 'field' in options) and 'auto' not in options:
options['auto'] = False
class Frac(BooleanOption, Flag, metaclass=OptionType):
"""``auto`` option to polynomial manipulation functions. """
option = 'frac'
@classmethod
def default(cls):
return False
class Formal(BooleanOption, Flag, metaclass=OptionType):
"""``formal`` flag to polynomial manipulation functions. """
option = 'formal'
@classmethod
def default(cls):
return False
class Polys(BooleanOption, Flag, metaclass=OptionType):
"""``polys`` flag to polynomial manipulation functions. """
option = 'polys'
class Include(BooleanOption, Flag, metaclass=OptionType):
"""``include`` flag to polynomial manipulation functions. """
option = 'include'
@classmethod
def default(cls):
return False
class All(BooleanOption, Flag, metaclass=OptionType):
"""``all`` flag to polynomial manipulation functions. """
option = 'all'
@classmethod
def default(cls):
return False
class Gen(Flag, metaclass=OptionType):
"""``gen`` flag to polynomial manipulation functions. """
option = 'gen'
@classmethod
def default(cls):
return 0
@classmethod
def preprocess(cls, gen):
if isinstance(gen, (Basic, int)):
return gen
else:
raise OptionError("invalid argument for 'gen' option")
class Series(BooleanOption, Flag, metaclass=OptionType):
"""``series`` flag to polynomial manipulation functions. """
option = 'series'
@classmethod
def default(cls):
return False
class Symbols(Flag, metaclass=OptionType):
"""``symbols`` flag to polynomial manipulation functions. """
option = 'symbols'
@classmethod
def default(cls):
return numbered_symbols('s', start=1)
@classmethod
def preprocess(cls, symbols):
if hasattr(symbols, '__iter__'):
return iter(symbols)
else:
raise OptionError("expected an iterator or iterable container, got %s" % symbols)
class Method(Flag, metaclass=OptionType):
"""``method`` flag to polynomial manipulation functions. """
option = 'method'
@classmethod
def preprocess(cls, method):
if isinstance(method, str):
return method.lower()
else:
raise OptionError("expected a string, got %s" % method)
def build_options(gens, args=None):
"""Construct options from keyword arguments or ... options. """
if args is None:
gens, args = (), gens
if len(args) != 1 or 'opt' not in args or gens:
return Options(gens, args)
else:
return args['opt']
def allowed_flags(args, flags):
"""
Allow specified flags to be used in the given context.
Examples
========
>>> from sympy.polys.polyoptions import allowed_flags
>>> from sympy.polys.domains import ZZ
>>> allowed_flags({'domain': ZZ}, [])
>>> allowed_flags({'domain': ZZ, 'frac': True}, [])
Traceback (most recent call last):
...
FlagError: 'frac' flag is not allowed in this context
>>> allowed_flags({'domain': ZZ, 'frac': True}, ['frac'])
"""
flags = set(flags)
for arg in args.keys():
try:
if Options.__options__[arg].is_Flag and arg not in flags:
raise FlagError(
"'%s' flag is not allowed in this context" % arg)
except KeyError:
raise OptionError("'%s' is not a valid option" % arg)
def set_defaults(options, **defaults):
"""Update options with default values. """
if 'defaults' not in options:
options = dict(options)
options['defaults'] = defaults
return options
Options._init_dependencies_order()
PK ]ZZZ�4�#w #w sympy/polys/polyquinticconst.py"""
Solving solvable quintics - An implementation of DS Dummit's paper
Paper :
https://www.ams.org/journals/mcom/1991-57-195/S0025-5718-1991-1079014-X/S0025-5718-1991-1079014-X.pdf
Mathematica notebook:
http://www.emba.uvm.edu/~ddummit/quintics/quintics.nb
"""
from sympy.core import Symbol
from sympy.core.evalf import N
from sympy.core.numbers import I, Rational
from sympy.functions import sqrt
from sympy.polys.polytools import Poly
from sympy.utilities import public
x = Symbol('x')
@public
class PolyQuintic:
"""Special functions for solvable quintics"""